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  • 2000-2004  (29)
  • 1990-1994  (1.100)
  • 1920-1924
  • 1900-1904
  • Genetics  (1.129)
  • 1
    ISSN: 1432-198X
    Schlagwort(e): Key words Glomerulocystic kidney disease ; Oligohydramnion ; Renal failure-neonate ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Two newborns with glomerulocystic kidney disease manifesting as late onset oligohydramnion and neonatal anuria, yet without severe respiratory distress, are presented. They had a similar perinatal course and associated clinical manifestations. No associated congenital or inherited malformation syndrome could be defined. Both infants’ parents were first degree cousins and belonged to the same small Bedouin tribe, and neither they nor the infants’ siblings had polycystic kidneys or renal insufficiency, pointing to either a possible genetic etiology or a common external toxic exposure.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Intensive care medicine 26 (2000), S. S057 
    ISSN: 1432-1238
    Schlagwort(e): Key words Critical illness ; Intensive care ; Severity of illness ; Scoring systems ; Genetics ; Susceptibility ; Education
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Risk of critical illness is determined both by genetic and environmental influences, particularly those relating to infectious and cardiovascular diseases. Physiologically-based scoring systems cannot measure prior risk because they do not quantify physiological reserve independently of the acute illness. Genetic profiling could be useful for risk assessment. Early detection of critical illness involves identifying physiological ’triggers' for referral; this requires the education of nursing and medical staff in their significance. Analysis of the relationship between risk factors and interventions may need complex modelling techniques. Therapeutic strategies depend on the nature of the underlying problem: the most useful are likely to be those which enhance tissue oxygen delivery and resistance to infection.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 159 (2000), S. S35 
    ISSN: 1432-1076
    Schlagwort(e): Key words Obesity ; Genetics ; Child ; Nutrient balance ; Energy balance ; Environment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The epidemic diffusion of obesity in industrialised countries has promoted research on the aetiopathogenesis of this disorder. The purpose of this review is to focus mainly on the contribution that European research has made to this field. Available evidence suggests that obesity results from multiple interactions between genes and environment. Parents obesity is the most important risk factor for childhood obesity. Twin, adoption, and family studies indicated that inheritance is able to account for 25% to 40% of inter-individual difference in adiposity. Single gene defects leading to obesity have been discovered in animals and, in some cases, confirmed in humans as congenital leptin deficiency or congenital leptin receptor deficiency. However, in most cases, genes involved in weight gain do not directly cause obesity but they increase the susceptibility to fat gain in subjects exposed to a specific environment. Both genetic and environmental factors promote a positive energy balance which cause obesity. The relative inefficiency of self-adapting energy intake to energy requirements is responsible for fat gain in predisposed individuals. The role of the environment in the development of obesity is suggested by the rapid increase of the prevalence of obesity accompanying the rapid changes in the lifestyle of the population in the second half of this century. Early experiences with food, feeding practices and family food choices affect children's nutritional habits. In particular, the parents are responsible for food availability and accessibility in the home and they affect food preferences of their children. Diet composition, in particular fat intake, influences the development of obesity. The high energy density and palatability of fatty foods as well as their less satiating properties promotes food consumption. TV viewing, an inactivity and food intake promoter, was identified as a relevant risk factor for obesity in children. Sedentarity, i.e. a low physical activity level, is accompanied by a low fat oxidation rate in muscle and a low fat oxidation rate is a risk factor of fat gain or fat re-gain after weight loss. Conclusion Further research is needed to identify new risk factors of childhood obesity, both in the genetic and environmental areas, which may help to develop more effective strategies for the prevention and treatment of obesity.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 159 (2000), S. S183 
    ISSN: 1432-1076
    Schlagwort(e): Key words Database ; Genetics ; Information services ; Internet ; Mutation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Thanks to the World Wide Web, most results of research in genetics are made available in public databases. At the present time there are resources on genetic diseases, genes and their location, mutations of already cloned genes and on laboratories performing the mutation analysis. The main resources on phenotypes are On-line Mendelian Inheritance in Man (OMIM), Pedbase, GeneClinics, London Dysmorphology Database (LDDB) and Orphanet. The main resources on human genes are, in addition to OMIM, the Genome Database, Genatlas and Genecard. There are also two major sequence databases. All of them can be queried using the OMIM number of the disease. Central databases of mutations, as well as locus specific databases have been created. Their list is maintained at the Human Genome Organisation mutation database initiative website. Several initiative have been taken to integrate all these data and help the clinician to find out quickly what he/she needs. The website of the National Center for Biotechnology Information is the best example of such an effort with sections on diseases, a genome guide, and locus links. Several databases of genetic testing resources have been established. GeneTests is an on-line genetics resource that contains a directory of North American laboratories providing testing for heritable disorders. Orphanet is a similar database on French services which is in the process of becoming a European database. Conclusion Even if clinicians do not have as many services at their disposal as the molecular geneticists, various useful databases already exist and should no longer be ignored in practice.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 159 (2000), S. S208 
    ISSN: 1432-1076
    Schlagwort(e): Key words Cardiovascular disease ; Cystathionine β-synthase ; Genetics ; Methylenetetrahydrofolate reductase ; Mild hyperhomocysteinaemia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Over the last decade mild hyperhomocysteinaemia has widely been recognised as a new risk factor for arteriosclerosis and thrombosis. Main regulating enzymes of homocysteine (Hcy) metabolism are cystathionine β-synthase (CBS), methionine synthase and methylenetetrahydrofolate reductase (MTHFR). Early studies on patients with vascular disease described elevated Hcy concentrations after methionine loading and decreased CBS activity, resembling heterozygotes for CBS deficiency. Therefore, heterozygosity for CBS deficiency was proposed as the main cause of mild hyperhomocysteinaemia. However, more recent enzymatic and molecular genetic studies have demonstrated that heterozygosity for CBS deficiency is not or only a very minor cause of mild hyperhomocysteinaemia in vascular disease. We discovered two common genetic causes of mild hyperhomocysteinaemia, the 677C 〉 T and the 1298A 〉 C mutations in the coding region of MTHFR. The 677C 〉 T mutation causes reduced enzyme activity with thermolabile protein properties, elevated Hcy and low-normal or decreased plasma folate levels. The 1298A 〉 C mutation relates also to decreased enzyme activity, but not to thermolabile protein, and Hcy and folate levels are not influenced. However, compound heterozygosity for these two mutations, i.e. individuals with the 677CT/1298AC genotype, have elevated Hcy and decreased plasma folate levels. Gene-enviroment interactions between 677C 〉 T and folate is demonstrated in individuals with the 677TT genotype. Those with low-normal folate have elevated Hcy, whereas those with high-normal folate have normal Hcy concentrations. The elevated Hcy levels due to these mutations can be normalised by administration of folate, but whether folate reduces the risk of cardiovascular disease remains to be established. Conclusion Heterozygosity for cystathionine β-synthase deficiency is a minor cause of hyperhomocysteinaemia. The current data on mutations in the methylenetetrahydrofolate reductase gene do not tell us whether elevated plasma homocysteine plays a causal role in vascular disease. Low cellular vitamin status may be a possible cause and homocysteine may just be a marker for this situation.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1364-6753
    Schlagwort(e): Key words Parkinson's disease ; Familial Parkinson's disease ; Synuclein ; Parkin ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: ABSTRACT¶Parkinson's disease (PD) is a neurodegenerative disease with clinical features resulting from deficiency of dopamine in the nigrostriatal system. Most PD cases are sporadic and the primary cause of the disease is still unknown. Recently, familial PD and parkinsonism have received much attention because these forms of the disease might provide clues to the genetic risk factors involved in the pathogenesis of idiopathic PD. To date, two causative genes, α-synuclein and the parkin gene, have been identified. α-Synuclein is involved in the pathogenesis of an autosomal dominant form of PD and constitutes a major component of the Lewy body, which is a pathological hallmark of idiopathic PD. In addition, mutations in the parkin gene have been identified as the cause of autosomal recessive juvenile parkinsonism (AR-JP). AR-JP manifests itself as a highly selective degeneration of the substantia nigra and the locus coeruleus, but without Lewy body formation. In addition to these two genes, four chromosomal loci have been linked to other forms of familial PD. Furthermore, there are a number of other pedigrees of familial PD in which linkage to known genetic loci has been excluded. Molecular cloning of these disease genes and elucidation of the function of their gene products will greatly contribute to our understanding of the pathogenesis of idiopathic PD.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    The journal of headache and pain 1 (2000), S. S147 
    ISSN: 1129-2377
    Schlagwort(e): Key words Dopamine ; Migraine ; Genetics ; DRD2
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Molecular genetics offers a novel approach to the understanding and management of migraine since the disorder is known to have a strong genetic component. In recent studies, polymorphisms in the genes for dopamine receptors have been evaluated. Both positive and negative association studies have been reported. In particular, these data suggest that activation of the DRD2 receptor plays a modifying role in the pathophysiology of migraine. As a result, existing data provide a molecular rationale for the documented efficacy of dopamine D2 receptor antagonists in the treatment of migraine. Therefore, at the present time, molecular genetic data provide support for the hypothesis that susceptibility to migraine may be modified, in part, by variations in dopamine DRD2 receptor function.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    The journal of headache and pain 1 (2000), S. S157 
    ISSN: 1129-2377
    Schlagwort(e): Key words Migraine ; Chronic tension type headache ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Pathophysiological studies have dominated migraine research for several years. However, these studies are difficult to interpret because it is difficult to decide whether the observed phenomena are primary or secondary to the migraine attack. For that reason it is important that future migraine research focus on studies that concern migrain etiology. Migraine is a paroxysmal disorder. It is most likely and ion-channel disorder like familial hemiplegic migraine. The present paper focuses on genetic factors in migraine and chronic tension-type headache.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1129-2377
    Schlagwort(e): Key words Cluster headache ; Familial occurrence ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A Danish genetic study showed increased risk of cluster headache (CH) among relatives of CH patients. We studied the families of 191 CH patients (118 males, 73 females; mean age 45.9 years) attending the Milan Headache Center. Information on 3589 relatives was collected by direct interview of the probands (n = 118) or by mailed questionnaire (n = 73). The diagnostic criteria of the IHS were used. A positive family history was found in 19% (37 of 191) of the families. A total of 32 first-degree (32 of 1036, 3.1%) and 15 second-degree (15 of 2553, 0.6%) relatives were affected. The relative risk of CH was 26.89 (95% CI, 17.57–36.21) in the first-degree relatives and 4.35 (95% CI, 2.13–5.21) in second-degree relatives. This study shows increased familial risk of cluster headache in an Italian population and confirms that cluster headache is, in some families, and inherited disorder.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    The journal of headache and pain 1 (2000), S. S135 
    ISSN: 1129-2377
    Schlagwort(e): Key words Migraine ; Headache ; Genetics ; Serotonin ; Dopamine ; Mitochondria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Migraine carries a significant hereditary determination. Familial hemiplegic migraine (FHM) has been recently linked to mutations in the CACNA1A gene on chromosome 19. CACNA1A codes for a subunit of a neural calcium channel. Other linkage loci on chromosome 1q21-23 and 1q31 have been reported. Several linkage and association studies have been performed to determine the role of the CACNA1A gene, and of other candidate genes implicated in the metabolism of serotonin and dopamine, in the more common types of migraine. Co-morbidity of migraine with vascular events has been analysed versus genetic prothrombotic factors and mitochondrial DNA, and genes involved in the inflammatory cascade have been explored. Though no definite conclusions have emerged from these studies as yet, molecular genetics of migraine can be expected to unravel the complex aetiologies of these fascinating diseases.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    The journal of headache and pain 1 (2000), S. S153 
    ISSN: 1129-2377
    Schlagwort(e): Key words Migraine ; Genetics ; Dopamine ; Hypersensitivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Migraine is a common chronic disorder with an etiology still mostly unknown. Several neurotransmitters such as dopamine and serotonin are considered to be involved in the pathogenesis of the disease and the study of their systems is crucial in the understanding of migraine. Dopaminergic receptors are variously represented in human CNS and periphery. The hypothesis that a hypersensitivity of the dopaminergic system may have a role in migraine is based on clinical and genetic data. Genetic data are represented by association studies using dopaminergic genes as candidate genes which show that the D2 receptor gene appears to be involved in the pathogenesis of migraine.
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    The journal of headache and pain 1 (2000), S. S141 
    ISSN: 1129-2377
    Schlagwort(e): Key words Migraine ; Genetics ; Human leukocyte antigens ; Heredity ; Susceptibility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Human leukocyte Antigens (HLA) are encoded by genes located on chromosome 6p21. Genes important in migraine are being recognized in two basic ways: association studies and linkage analysis. One of the strongest associations is with the HLA region. Actually, genome scan studies suggest that multiple genes are involved in both migraine without aura (MWoA) and migraine with aura (MWA). However, both MWoA and MWA are disorders in which multiple factors, including environmental and genetic factors, confer disease susceptibility. Linkage analysis is identifying new candidate genes that will help to explain the etiology of migraine. In this review previous studies regarding genetic susceptibility to migraine are analyzed, particularly those related to the HLA region. I discuss evidence that HLA shared-hyplotypes in MWoA-affected pairs in different than that expected, that HLA-DR2 antigen provides additional basis for the proposed genetic heterogeneity between MWoA and MWA, and lastly that TNFB gene studies seem to play an important role in the susceptibility to MWoA. In the past years, major advances hae been made in understanding the genetic foundation of MWoA and MWA. Our reported genome-scan studies support the concept that MWoA/MWA are coinherited with a particular HLA region. However, the examination of candidate genes (Ca2+ channel, vascular, CNS, etc.) in a large migraine population seems to be the correct direction in which we have to move. More MWoA/MWa gene studies are needed to test this developing hypothesis and to further establish the complete genetic scenario of migraine.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 100 (2000), S. 401-408 
    ISSN: 1432-2242
    Schlagwort(e): Key words Complementary genes ; Extreme virus resistance ; Genetics ; Necrotic tubers ; Restricted virus distribution ; Solanum tuberosum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  The potato cultivar ’Shepody’ is susceptible to a number of potato viruses including potato virus Y (PVY, potyvirus) but was found to possess extreme resistance to another potyvirus, potato virus A (PVA). ’Shepody’ plants were resistant to PVA infection in manual and graft inoculations. PVA replication was not detected in any of the inoculated plants by ELISA, an infectivity assay and RT-PCR. However, ’Shepody’ plants grafted with shoots containing PVA developed a novel symptomology which resembled a virus infection in appearance and in rate of translocation to the entire plant. Efforts to transmit the symptom-inducing agent manually failed. Graft-inoculation to potato virus indicator plants and PVA-susceptible potato plants showed that the symptom inducer was PVA at an extremely low concentration, detected using RT-PCR followed by Southern blot assay. Tubers from grafted but resistant ’Shepody’ plants had necrotic surfaces and internal spots. PVA was detected from necrotic areas but not from the non-necrotic ones. However, plants resulting from necrotic tubers were free from aerial leaf symptoms observed in grafted plants and produced non-necrotic normal tubers. A trace-back of the parental lineage of ’Shepody’ indicated that the resistance had been introgressed from the cultivar ’Bake King’. Analysis of progeny of a cross of resistant ’Shepody’ to the susceptible ’Goldrus’ indicated that this resistance is controlled by two independent dominant complementary genes in contrast to monogenic resistance reported for other potato viruses.
    Materialart: Digitale Medien
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  • 14
    ISSN: 1432-2242
    Schlagwort(e): Key words Avicennia marina ; Microsatellite ; Mangrove ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  An enriched microsatellite library of the mangrove species Avicennia marina was constructed, in which 85.8% of the clones contained microsatellite sequences. Of the microsatellite repeat sequences isolated, 55.0% were di-nucleotides, 34.2% were tri-nucleotides, 50.0% were perfect, 24.2% were imperfect, and 15.0% were compound. Four different di-nucleotide repeats were isolated with repeat lengths ranging from 5 to 33; ten different tri-nucleotide repeats were isolated with repeat lengths ranging from 3 to 25. The most common di-nucleotide was the AC/TG repeat; the most common tri-nucleotide was the CCG/GGC repeat. Sixteen microsatellite sequences were selected for primer design, and 6 primers were selected to investigate the polymorphism detected among 15 individuals of A. marina from three natural populations in Australia. A total of 40 alleles were detected at 6 microsatellite loci. The number of alleles per microsatellite locus ranged from 5 to 13. On average, 7 alleles were detected per locus. All microsatellite loci showed high levels of gene diversity (heterozygosity), with values ranging from 0.53 to 0.88; the mean value of gene diversity was 0.70. Microsatellite loci were also tested for conservation across Avicennia species. There was a decline in amplification success with increasing divergence between Avicennia species. The results indicate that microsatellites are abundant in the Avicennia genome and can be valuable genetic markers for assessing the effects of deforestation and forest fragmentation in mangrove communities, which is an important issue for mangrove conservation and afforestation schemes.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 101 (2000), S. 234-240 
    ISSN: 1432-2242
    Schlagwort(e): Key words Cherry ; Genetics ; Compatibility ; Incompatibility ; Isoelectric focusing ; Prunus avium ; Ribonuclease
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  The (in)compatibility genotypes of two self-compatible sweet cherry selections, JI 2420 and JI 2434, originating from the John Innes Institute were re-examined. The selections and seedlings derived from them were analysed for stylar ribonucleases, which are known to correlate with S alleles, and the outcome of test crosses was recorded. JI 2420, which had been reported previously as S 3 S 4 ", where " indicates loss of pollen activity, was deduced to have the genotype S 4 S 4 ’. For JI 2434, which had been reported previously as S 3 S 4 0 , S 3 S 3 0 or S 3 S 3 ", where 0 indicates loss of pollen and stylar activity, two different clones were identified. One, at East Malling, was deduced to be S 3 "S 4 ; the other, at Ahrensburg, appeared to be S 3 S 3 " or S 3 S 3 0 .
    Materialart: Digitale Medien
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  • 16
    ISSN: 1432-1211
    Schlagwort(e): Key words Skin ; Genetics ; TNFA ; ¶Inflammation ; PCR-RFLP
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  Mechanisms underlying susceptibility to skin irritants are not clearly understood. Cytokines play a key role in inflammation, and functional polymorphisms in cytokine genes may affect responses to irritants. We investigated the relationship between polymorphism in the tumor necrosis factor (TNF) α-chain gene and responses to irritants. Volunteers (n=221) tested with sodium dodecyl sulfate (SDS) and benzalkonium chloride (BKC) were divided into responders and nonresponders and high and low irritant-threshold groups. DNA was assayed for the TNF-308 polymorphism by a polymerase chain reaction-restriction fragment length polymorphism method. There was a significant increase in the A allele (P=0.030) and AA genotype (P=0.023) in both the SDS low irritant-threshold group and in SDS responders (A allele P=0.022, AA genotype P=0.048). In the BKC low irritant-threshold group, we found a significant increase in the A allele (P=0.002) and AA genotype (P=0.016). Individuals with a low threshold to both irritants demonstrated a significant increase (P=0.002) in the A allele. This is the first description of a nonatopic genetic marker for irritant susceptibility in normal individuals. Genotyping for theTNF-308 polymorphism may thus contribute to screening of individuals deemed at risk of developing irritant contact dermatitis.
    Materialart: Digitale Medien
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  • 17
    ISSN: 1432-1459
    Schlagwort(e): Key words Progressive ¶supranuclear palsy ; Genetics ; Clinical characteristics ; Parkinsonism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Genetic studies have detected an association between the presence of the τ gene A0 allele and patients with progressive supranuclear palsy (PSP). This study examined whether patients with this polymorphism exhibit distinct demographic or clinical characteristics. We studied 26 patients who fulfilled clinical criteria for the diagnosis of PSP, 20 who had the A0/A0 genotype and 6 who had other genotypes. A questionnaire on demographic data, past medical history, familial history, and initial symptoms was completed as part of the consultation. A complete neurological examination was performed and PSP symptoms were quantified following Golbe’s PSP disability scale. We found a significant difference in the age at onset of PSP symptoms, which was 65.9 ± 5.3 years in the A0/A0 group and 71.2 ± 5.6 in the non-A0/A0 group (P = 0.016). There were no significant differences in the years from disease onset between the two groups. Symptom severity did not differ significantly in patients with the different A0/A0 genotypes. The detection of significantly lower age at onset with the A0/A0 alleles is consistent with the known association of this genotype as a risk factor for PSP. No significant differences were detected in symptom severity between the two groups of patients.
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  • 18
    ISSN: 1432-1459
    Schlagwort(e): Key words Amyotrophic lateral sclerosis ; Genetics ; Presenilin-1 intron 8 polymorphism ; Apoptosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The mechanisms underlying motor neuron degeneration in amyotrophic lateral sclerosis are not fully understood. Recent studies suggest that apoptosis is involved in the abnormal neural death that occurs in this devastating disease. Presenilin-1, a transmembrane protein, seems to be implicated in apoptosis. To determine whether presenilin-1 intron 8 polymorphism has an influence in the course of amyotrophic lateral sclerosis, we examined this polymorphism genotypes in a large group of patients (n=72) with amyotrophic lateral sclerosis and in a random sample of 213 healthy individuals. The results showed a significant difference in genotype (P 〈 0.04) and allele (P 〈 0.03) distribution between patients and controls. These results suggest a possible intervention of presenilin-1 in the pathogenesis of amyotrophic lateral sclerosis.
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  • 19
    ISSN: 1432-1459
    Schlagwort(e): Key words Parkinson’s disease ; Monoamine oxidase B ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Monoamine oxidase B (MAOB) metabolises dopamine and activates neurotoxins known to induce parkinsonism in humans and primates. Therefore the MAOB gene (MAOB; Xp15.21–4) is a candidate gene for Parkinson’s disease (PD). Longer length dinucleotide repeat sequences in a highly polymorphic GT repeat region of intron 2 of this gene showed an association with PD in an Australian cohort. We repeated this allele-association study in a population of 176 Chinese PD patients ¶(90 men, 86 women) and 203 age-matched controls (99 men, 104 women). Genomic DNA was extracted from venous blood and the polymerase chain reaction was used to amplify the appropriate regions of the MAOB gene. The length of each (GT) repeat sequence was determined by 5% polyacrylamide denaturing gel electrophoresis. There was no significant difference in allele frequencies of the (GT) repeat allelic variation between patients and controls (χ2 = 2.48; df = 5, P 〈 0.75). Therefore the longer length GT repeat alleles are not associated with PD in this Chinese population. Possible reasons for the discrepancy between Chinese and Australian populations include a different interaction between this genetic factor and environmental factors in the two populations and the possibility that the long length GT repeat alleles may represent a marker mutation, genetically linked to another susceptibility allele in whites but not in Chinese. Methodological differences in the ascertainment of cases and controls in this cohort could also explain the observed differences. Further study is required to determine whether the longer length GT repeat alleles are true susceptibility alleles in PD.
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  • 20
    ISSN: 1432-1459
    Schlagwort(e): Key words Multiple sclerosis ; Genetics ; ICAM-1 gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract An increased amount of the intercellular adhesion molecule (ICAM) 1 molecule has been found in the blood of actively relapsing multiple sclerosis (MS) patients, but is unclear whether this enhanced expression is partially causative of the MS process, or whether it is merely an epiphenomenon of the inflammatory-immunological reaction. Using the transmission disequilibrium test (TDT), we studied exon 4 and exon 6 polymorphism of the ICAM-1 gene from 157 families with both parents, one affected and one healthy sib coming from Sardinia, an Italian island having a high incidence and prevalence of MS. TDT did not show variation in the expected 50:50 frequency in transmission in either healthy or affected sibs, using phenotypic or genotypic analysis. Moreover, independence from the predisposing HLA-DRB1-DQA1-DQB1 haplotype was confirmed by TDT analysis performed on the patients stratified according to the presence or absence of the HLA-DRB1, DQA1, DQB1 Sardinian predisposing haplotypes. Our data suggest that the increased expression of the ICAM-1 molecule observed in both blood and periplaque microvessels may be considered a consequence of the inflammatory process rather than the result of a genetic variation.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurology 247 (2000), S. 81-87 
    ISSN: 1432-1459
    Schlagwort(e): Key words Dementia ; Vascular ¶dementia ; Alzheimer’s disease ; Risk factors, stroke ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This review describes differing profiles of vascular risk factors in different types of dementia. Although vascular risk factors are related to various types of strokes, their independent effect on the occurrence of poststroke dementia appears to be small. Various risk factors have been identified for microangiopathy-related cerebral abnormalities, such as white matter changes and lacunae, which are the core lesions for the development of a vascular dementia syndrome without stroke symptoms. Most consistently, arterial hypertension and diabetes mellitus have been found to be associated with such brain abnormalities. Diastolic blood pressure seems to be of particular importance as recent investigations demonstrate that this factor is related to the course of multiple lacunar strokes and the progression of white matter disease. Epidemiological studies report that various vascular risk factors including arterial hypertension, diabetes mellitus, and atrial fibrillation may also be associated with Alzheimer’s disease. There is also evidence of a direct relationship between Alzheimer’s disease and general atherosclerosis. Further investigations are needed to determine whether these associations are due to the weakness of diagnostic criteria, or whether vascular risk factors indeed modulate the clinical expression of primary degenerative dementia. Common susceptibility genes leading to shared risk factors may be one of the reasons for a higher coincidence of Alzheimer’s disease and vascular dementia than can be expected by chance. A modulatory effect of vascular risk factors in the development of primary degenerative dementia may extend treatment options.
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  • 22
    ISSN: 1432-1459
    Schlagwort(e): Key words Multiple sclerosis ; Siblings ; Genetics ; Oligoclonal bands ; Measles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We found that 19% (9/47) of healthy siblings of patients with clinically definite multiple sclerosis had an intrathecal immunological reaction with two or more 2 CSF-enriched oligoclonal bands (OCBs), in contrast to (4%) (2/50) unrelated healthy controls. Furthermore, in this group of nine healthy sibs the measles CSF IgG antibody titers were higher than that of the other sibs and that of controls. There were also differences in the serum titers for measles IgG antibody, which were higher in the group of all healthy sibs than in healthy volunteers, and (as with CSF titers) higher in the subgroup of healthy sibs with two or more 2 CSF-enriched OCBs than the other sibs. Thus a significant proportion of healthy siblings to MS patients have a partially hyperimmune condition similar to that occurring in MS, which in 19% manifested itself as an OCB reaction, in 9% as increased CSF measles IgG antibody titers, and in 21% as increased serum measles IgG antibody titers, these phenomena tending to occur in the same individuals. This condition is characterized by CSF-enriched OCBs with undefined specificity, although some increased antiviral reactivity is found both in the serum and CSF. While it needs further characterization, a genetic trait interacting with common infections is suggested. The recurrence risk of this condition is approximately five times higher than the 3–4% recurrence risk for manifest MS reported for sibs.
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  • 23
    ISSN: 1433-8491
    Schlagwort(e): Key words Dopamine receptor D4 ; Genetics ; Personality inventory ; Polymorphism ; Excitement-Seeking
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract An association between long alleles of a variable number tandem repeat (VNTR) polymorphism in the dopamine receptor D4 gene and the extraversion related personality traits Excitement and Novelty Seeking has been reported in healthy subjects. In an attempt to replicate the previous findings, 256 healthy Caucasian volunteers were analysed for a potential relationship between the dopamine receptor D4 exon III VNTR polymorphism and Extraversion as assessed by the Revised Neo Personality Inventory (NEO PI-R). The present study did not yield evidence for an association between Extraversion and the dopamine receptor D4 polymorphism.
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  • 24
    ISSN: 1433-8491
    Schlagwort(e): Key words Pharmacogenetics ; Genetics ; Risk factor ; Choreoathetotic movements
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In the search for genetic factors contributing to tardive dyskinesia, dopamine receptor genes are considered major candidates. The dopamine D3 receptor is of primary interest as dopamine D3 receptor knock-out mice show locomotor hyperactivation resembling extrapyramidal side-effects of neuroleptic treatment. Furthermore, Steen and colleagues (1997) recently reported an association between tardive dyskinesia and a dopamine D3 receptor gene variant. In the present study we tried to replicate this finding. We investigated 157 patients with schizophrenia or schizoaffective disorder receiving long-term neuroleptic medication who never or persistently displayed tardive dyskinesia. As advanced age is a main risk factor for tardive dyskinesia, we also compared older patients with a long duration of schizophrenia not displaying tardive dyskinesia to younger patients with a shorter duration of the illness displaying tardive dyskinesia. However, we found no evidence that the dopamine D3 receptor gene is likely to confer susceptibility to the development of tardive dyskinesia.
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  • 25
    ISSN: 1590-3478
    Schlagwort(e): Key words Nervous system ; Cavernous angiomas ; Genetics ; Onset symptoms
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We performed a clinical and genetic study of patients affected by cavernous angiomas (CA) of the nervous system. We examined initial signs and symptoms in sporadic and familial cases. We obtained clinical, neuroimaging and genetic data on 15 Italian patients with CA of the nervous system with positive, doubtful or apparently negative family history. Genetic markers surrounding three different gene regions (7q, 3q and 7p) were analysed. In one small family, genetic linkage was consistent with all chromosome loci. In another family with the unusual association of cerebral and spinal CA, linkage with chromosome 7q and, likely, 7p was excluded, while linkage with locus 3q was possible. Our results indicate that Italian families with CA may show genetic heterogeneity. Non-specific and subtle onset symptoms hide the presence of CA within families. Patients with multiple CA may have silent cerebral lesions confirming the low penetrance of clinical signs in spite of radiological ones.
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Neurological sciences 21 (2000), S. S89 
    ISSN: 1590-3478
    Schlagwort(e): Key words Evoked potentials ; Ceroid lipofuscinoses ; Mutation ; Classification ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The importance of visual evoked potential (VEPs) and electroencephalography for diagnosing and distinghishing the infantile (INCL), late-infantile (LINCL) and juvenile (JNCL) forms of neuronal ceroid lipofuscinoses (NCL) is well established. Variant forms with protracted clinical courses and atypical symptoms have been described recently, whose neurophysiological characteristics sometimes overlap those of LINCL and JNCL. It is unclear whether these variant forms are due to phenotypic variability of known genetic defects, or represent new mutations. Twenty-eight NCL patients have been diagnosed at our institute; a proportion of them were investigated genetically. In 17 we performed neurophysiological investigations including VEPs, brainstem auditory (BAEP) and upper limb somatosensory (SEP) evoked potentials. We found typical and diagnostic electrophysiological involvement of the visual system in 8 patients with classic forms of NCL. Furthermore, the distinctive features of the multimodal evoked potentials in most of the six patients with variant NCL suggest that these are distinct genetic entities.
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Neurological sciences 21 (2000), S. 373-377 
    ISSN: 1590-3478
    Schlagwort(e): Key words Myoclonus-dystonia ; Essential myoclonus ; Dystonia ; Alcohol ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We present the clinical profile of a group of patients with myoclonus and dystonia sensitive to alcohol and address these cases in the context of essential myoclonus. Six patients from 4 families were selected: 4 men and 2 women with myoclonus affecting predominantly the arms. Active movements of these segments elicited the dystonic and myoclonic movements. A marked improvement with alcohol intake was seen. Laboratory findings including EEG, SSEP, and cranial CT and MRI were normal. Surface EMG recording showed bursts with duration of 30–112 ms in 3 patients. One patient showed a triphasic recording pattern (agonist-antagonist-agonist) of ballistic type. Our findings suggest that the myoclonus-dystonia disorder is present in Brazilian patients.
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  • 28
    ISSN: 1437-2320
    Schlagwort(e): Key words Von Hippel-Lindau disease ; Hemangioblastoma ; Endolymphatic sac tumor ; Angiogenesis ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Von Hippel-Lindau disease (VHL) is a hereditary cancer syndrome caused by germline mutations of the VHL tumor suppressor gene. Major progress has been made in the last decade in both clinical and fundamental aspects of VHL. The VHL gene product, pVHL, has major and multiple functions: pVHL regulates not only first angiogenesis but also extracellular matrix formation and the cell cycle. A molecular diagnosis of VHL is now available, leading to a transformation in clinical management of patients and their families. Diagnosis of VHL has to be suspected in patients with a VHL-related tumor without familial history and especially in case of hemangioblastoma or endolymphatic sac tumors. Such patients should be systematically investigated for clinical and molecular evidence of VHL disease. Treatment of symptomatic hemangioblastomas remains mainly neurosurgical, often in emergency, but stereotactic radiosurgery is emerging as an alternative therapeutic procedure. In the future, antiangiogenic drugs could represent a potential medical treatment of CNS hemangioblastomas in view of their highly vascular structure. Lastly, visceral manifestations of VHL disease are also of critical importance and require early detection for effective treatment.
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Child's nervous system 16 (2000), S. 809-820 
    ISSN: 1433-0350
    Schlagwort(e): Keywords Pediatric neurosurgery ; Molecular biology ; Genetics ; Novel therapeutics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The new millennium beckons for novel advances in the diagnosis and treatment of pediatric neurosurgical conditions. Almost every aspect of pediatric neurosurgery has changed over the last decade. Undoubtedly with the application of knowledge in molecular biology to human disease many aspects of neurosurgery, especially neuro-oncology and the field of neuro-developmental anomalies, will change appreciably over the next decade. Overall, the trend in surgery in general and neurosurgery in particular is toward less invasive procedures and possibly non-surgical interventions. This review will briefly cover many of the important areas of pediatric neurosurgery. We will describe the state-of-the-art of our subspecialty and discuss possible future directions.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Sexual plant reproduction 7 (1994), S. 290-296 
    ISSN: 1432-2145
    Schlagwort(e): Secale cereale ; Polyembryony ; Chromosome mosaics ; Rye ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have obtained one plant regenerated from rye tissue culture which showed a high percentage of polyembryonic seeds in its progeny. The mutation inducing the development of extra embryos is also influencing erroneous cell division, mitosis and meiosis. The genetic analysis indicated that the aptitude for polyembryonic seed formation is a heritable trait controlled by a dominant gene. However, for expression of the phenotype the female parent should have a specific cytoplasm.
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  • 31
    ISSN: 1432-2242
    Schlagwort(e): Breeding ; Helminthosporium turcicum ; RFLP ; QTLs ; Disease-resistance ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract RFLPs were used to investigate components of host-plant response to Exserohilum turcicum in 150 unselected F2∶3 lines of a B52/Mo17 maize population. Following inoculation with spore suspensions of the pathogen (race 0), components of disease development were measured and then quantitative trait mapping was performed to identify the location and effects of quantitative trait loci (QTLs) determining host-plant response. Components of interest were the average number of lesions per leaf, the average percent leaf tissue diseased (severity) and the average size of lesions (cm2). Based on a LOD threshold of 2.31 (P〈0.05), the number of lesions appears to be associated with QTLs on chromosomes 1S, 3L, 5S. Severity was associated with analogous regions and, in addition, QTLs on chromosomes 7L and 8L. Most QTLs, for either of these two components, involve additive gene action and partial dominance or overdominance. In contrast, lesion size was associated with QTLs on chromosomes 7L and 5L; recessive gene action may be involved at 7L.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 89 (1994), S. 959-963 
    ISSN: 1432-2242
    Schlagwort(e): Sugarcane ; Polyploidy ; Genetics ; Evolution ; Breeding ; DNA markers ; Arbitrarily primed PCR ; RAPD markers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Recent work has revealed random chromosome pairing and assortment in Saccharum spontaneum L., the most widely distributed, and morphologically and cytologically variable of the species of Saccharum. This conclusion was based on the analysis of a segregating population from across between S. spontaneum ‘SES 208’ and a spontaneously-doubled haploid of itself, derived from anther culture. To determine whether polysomic inheritance is common in Saccharum and whether it is observed in a typical biparental cross, we studied chromosome pairing and assortment in 44 progeny of a cross between euploid, meiotically regular, 2n=80 forms of Saccharum officinarum ‘LA Purple’ and Saccharum robustum ‘ Mol 5829’. Papuan 2n=80 forms of S. robustum have been suggested as the immediate progenitor species for cultivated sugarcane (S. officinarum). A total of 738 loci in LA Purple and 720 loci in Mol 5829 were amplified and typed in the progeny by arbitrarily primed PCR using 45 primers. Fifty and 33 single-dose polymorphisms were identified in the S. officinarum and S. robustum genomes, respectively (χ 2 at 98%). Linkage analysis of single-dose polymorphisms in both genomes revealed linkages in repulsion and coupling phases. In the S. officinarum genome, a map hypothesis gave 7 linkage groups with 17 linked and 33 unlinked markers. Four of 13 pairwise linkages were in repulsion phase and 9 were in coupling phase. In the S. robustum genome, a map hypothesis gave 5 linkage groups, defined by 12 markers, with 21 markers unlinked, and 2 of 9 pairwise linkages were in repulsion phase. Therefore, complete polysomic inheritance was not observed in either species, suggesting that chromosomal behavior is different from that observed by linkage analysis of over 500 markers in the S. spontaneum map. Implications of this finding for evolution and breeding are discussed.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric cardiology 15 (1994), S. 198-200 
    ISSN: 1432-1971
    Schlagwort(e): Subaortic stenosis ; Congenital heart disease ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The first case of multiple family members with discrete subaortic membrane and no other congenital defects is presented. One family member presents with findings suggesting a forme fruste of this disease. Increased surveillance of family members of individuals with discrete subaortic membrane is warranted, as the clinical findings of mild subaortic obstruction may be indistinguishable from those of an innocent flow murmur.
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric cardiology 15 (1994), S. 201-203 
    ISSN: 1432-1971
    Schlagwort(e): Tricuspid atresia ; Tricuspid hypoplasia ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Occurrence of a similar cardiac malformation in multiple family members has been reported for many lesions. Neither tricuspid atresia nor tricuspid annular hypoplasia and tricuspid atresia and one case of tricuspid annular hypoplasia with an atrial septal defect in siblings. The findings in this family suggest an autosomal recessive pattern of inheritance for abnormal tricuspid valve morphogenesis.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular medicine 72 (1994), S. 409-413 
    ISSN: 1432-1440
    Schlagwort(e): Myotonic dystrophy ; Limb girdle muscular dystrophy ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A family is reported in which a 29-year-old woman showed the clinical features of myotonic dystrophy while her 26-year-old brother presented with the clinical picture of limb girdle syndrome. In the affected female, direct genetic testing for the specific myotonic dystrophy mutation on chromosome 19 revealed abnormal expansion of a repeat unit containing the three nucleotides cytosine, thymine, and guanine (CTG) — typical for myotonic dystrophy — while her diseased brother displayed two normal alleles. This supports the hypothesis of the extremely rare occurrence of two clinically and genetically different myopathies in one family. Genetic analysis of six other family members showed that the father of the diseased siblings as well as all of his three brothers and sisters had a pathological CTG repeat expansion, and that the other two family members tested had a normal allelic pattern. The number of CTG repeats in the diseased women was approximately tenfold higher than in her asymptomatic relatives who revealed an abnormal allelic pattern. The increase in CTG repeats with transmission to a subsequent generation in this family was paralleled by a dramatic increase in the severity of myotonic dystrophy.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 50 (1994), S. 429-437 
    ISSN: 1420-9071
    Schlagwort(e): Genetics ; ecology ; DNA-transfer ; conjugation ; transformation ; transduction ; transposons ; dormant cells ; epilithon ; microbial colonisation ; symbiosis ; virus resistance ; biosafety ; release of genes ; insults to humanity ; evolution ; biodiversity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Genetic ecology is the extension of our modern knowledge in molecular genetics to studies of viability, gene expression and gene movements in natural environments like soils, aquifers and digestive tracts. In such milieux, the horizontal transfer of plasmid-borne genes between phylogenetically distant species has already been found to be much more frequent than had been expected from laboratory experience. For the study of exchanges involving chromosomally-located genes, more has to be learned about the behaviour of transposons in such environments. The results expected from studies in genetic ecology are relevant for considerations of evolution, biodiversity and biosafety. The role of this new field of research in restoring popular confidence in science and in its biotechnological applications is stressed.
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  • 37
    ISSN: 1432-0533
    Schlagwort(e): Key words: Amyotrophic lateral sclerosis ; Neuropathology ; Posterior column involvement ; Genetics ; Superoxide dismutase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Several missense mutations within exons 1, 2, 4 and 5 of the gene for Cu/Zn-binding superoxide dismutase (SOD1) have been discovered to be involved in the development of chromosome 21q-linked familial amyotrophic lateral sclerosis (FALS). We describe here an autopsied patient with FALS, in whom we have recently identified a novel missense mutation in exon 1 of the SOD1 gene. The neuropathological findings were compatible with those described previously in patients with FALS with posterior column involvement. This suggests that mutations of the SOD1 gene may be responsible for this form of FALS.
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  • 38
    ISSN: 1432-0533
    Schlagwort(e): Key words     Primitive neuroepithelial tumor ; Desmoplastic small cell tumor ; Brain tumor of infancy ; Immunocytochemistry ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract      We describe a case of a desmoplastic brain tumor which was initially resected from the right fronto-temporal region in a 2 year-old boy. This nodular, calcified tumor was vascularized by the internal carotid artery and the middle meningeal artery branches. Grossly, it contained several mucoid cysts. Light microscopy showed cords or nests of small cuboidal cells surrounded by a loose connective tissue and desmoplasic areas containing fibers and spindle cells. The cuboidal cells expressed epithelial, neuronal and neuroendocrine markers. Some foci of spindle cells showed glial differentiation. The tumor recurred 16 months later and displayed some characteristics of the small cell neuroepithelial component, mitoses being conspicuous. Electron microscopy revealed undifferentiated clear cells, some containing neurosecretory granules. Karyotyping demonstrated the following formula: 〈 15 〉 46, t(8;11) (q13; q11). The chromosome 11 breakpoint was different from that described in Ewing's sarcoma. This isolated translocation has not been previously reported to our knowledge. These unusual features lead us to report this case and to discuss its pathogenesis.
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  • 39
    ISSN: 1432-0533
    Schlagwort(e): Amyotrophic lateral sclerosis ; Neuropathology ; Posterior column involvement ; Genetics ; Superoxide dismutase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Several missense mutations within exons 1, 2, 4 and 5 of the gene for Cu/Zn-binding superoxide dismutase (SOD1) have been discovered to be involved in the development of chromosome 21q-linked familial amyotrophic lateral sclerosis (FALS). We describe here an autopsied patient with FALS, in whom we have recently identified a novel missense mutation in exon 1 of the SOD1 gene. The neuropathological findings were compatible with those described previously in patients with FALS with posterior column involvement. This suggests that mutations of the SOD1 gene may be responsible for this form of FALS.
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  • 40
    ISSN: 1432-0428
    Schlagwort(e): Genetics ; diabetes mellitus ; mitochondria ; maternal ; deafness
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Non-insulin-dependent diabetes mellitus (NIDDM) has a strong genetic component and maternal factors have recently been implicated in disease inheritance. The mitochondrial myopathies are a group of diseases which often show maternal inheritance as a result of mtDNA defects; some patients have impaired glucose tolerance. Occasional families with maternally inherited diabetes and deafness associated with a deletion or point mutation of mtDNA have been reported. To assess the importance of mitochondrial gene defects in NIDDM, 150 unrelated diabetic subjects from Wales, UK and 68 unrelated patients with diabetes and at least one affected sibling from England, UK were studied. Southern blot analysis did not show any large mtDNA deletions or duplications. One patient had a mutation in the mitochondrial tRNAleu(UUR) gene at bp 3243. This mutation is commonly associated with the syndrome of mitochondrial encephalomyopathy, lactic acidosis and stroke like episodes (MELAS). Study of this patient and his siblings showed a distinct form of late-onset diabetes associated with nerve deafness but no clinical features of the MELAS syndrome. No diabetic subject was shown to have the mtDNA mutation at position 8344 (tRNAlys) which has previously been described in the syndrome of mitochondrial encephalomyopathy and red-ragged fibres (MERRF). The role of other mitochondrial gene defects in diabetes and the pathophysiological basis of glucose intolerance in patients with the MELAS mutation requires further elucidation.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Journal of biomedical science 1 (1994), S. 201-203 
    ISSN: 1423-0127
    Schlagwort(e): Hypertension ; Eicosanoid ; Rat ; Genetics ; Kidney
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The present paper reviews the evidence for a possible involvement of renal eicosanoids in the pathophysiology of high blood pressure in genetically hypertensive rats of the Lyon strain. Both in vivo and in vitro experiments suggest that an increased ability to synthesize the vasoconstrictor prostaglandin H2 and/or thromboxane A2 in renal vessels (1) acts as an autocrine amplifier of pressor agents and (2) may contribute to resetting the pressure natriuresis curve which is a prerequisite for the development and maintenance of hypertension.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 153 (1994), S. 372-377 
    ISSN: 1432-1076
    Schlagwort(e): Epilepsy ; Absences ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Clinical and EEG family data of 140 cases with early childhood epilepsy with absences are presented. The aim of the study was to evaluate, whether the occurrence of generalized tonic clonic seizures (GTCS) as a presenting symptom might correlate with family data, i.e. whether there are indications of heterogeneity. One hundred and forty cases were selected from the epilepsy family data base of the Neuropaediatric Department. The selection parameter was epilepsy with absences manifesting between the 1 st and 5th year of age. The incidence of seizures was evaluated in siblings, parents and parents' siblings. EEG records were available from 103 parents and 106 siblings. The analysis supports the assumption of heterogeneity within early childhood absence epilepsy. Parents and their sibs of cases manifesting with GTCS had seizures twice as often than parents and their sibs in the non-GTCS group. In the affected relatives of the GTCS group early onset GTCS prevailed, whereas in the relatives of the non-GTCS group absences were found more frequently. The EEG of relatives showed elevated incidences of spikes and waves and photosensitivity in both groups, indicating common genetic factors. In parents of the non-GTCS group, however, EEG pathology was significantly more frequent than in parents of the GTCS group. Comparing EEG pathology in parents with seizure risk in siblings, evidence for maternal preponderance in transmission of the seizure liability was found. Mothers' EEG seems to be the best predictor of the seizure risk in probands' siblings. Early childhood epilepsy with absences can be regarded as an intermediate type, showing overlap with early onset GTCS and myoclonic astatic epilepsy on the one side and with childhood absence epilepsy on the other.
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  • 43
    ISSN: 1432-0428
    Schlagwort(e): Genetics ; haplotype ; HLA-A ; HLA-DQ ; HLA-DR ; tumour necrosis factor ; diabetes mellitus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In Finland the haplotype A2, Cw1, B56, DR4, DQ8 is the third most common haplotype in insulin-dependent diabetic (IDDM) patients and has the highest haplotype-specific absolute risk for IDDM. Cw1, B56, DR4, DQ8 haplotypes containing HLA-A alleles other than A2 are infrequent in the population and are not associated with IDDM. Comparison of the A2 and non-A2 haplotypes at the DNA level showed that they were identical at HLA-B,-DR, and -DQ loci. Evidence that class I alleles confer susceptibility to IDDM was obtained from the two HLA-C, -B, -DR and -DQ haplotypes most frequently found in IDDM patients in Finland. A24, A3 and A2 on the Cw3, B62, DR4, DQ8 haplotype, and A28, A2 and A1 on the Cw7, B8, DR3, DQ2 were all found to be associated with IDDM. In Finland these seven haplotypes, including A2, Cw1, B56, DR4, DQ8, account for 33% of diabetic haplotypes and 10.3% of non-diabetic haplotypes (p〈0.00001). The contribution of the class I region to IDDM susceptibility was also apparent in those IDDM patients lacking the disease-predisposing class II alleles. Significantly more non-DR3/non-DR4 IDDM patients (47 of 55) possessed two of the IDDM-associated HLA-A alleles compared to non-DR3/non-DR4 control subjects (40 of 58; p=0.038). Moreover, IDDM patients confirmed by oligotyping as unable to form a ‘diabetes-susceptibility’ DQ heterodimer, tended to possess two diabetes-associated HLA-A alleles (12 of 13) compared to control subjects (12 of 20; p=0.056).
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 88 (1994), S. 754-758 
    ISSN: 1432-2242
    Schlagwort(e): Potato breeding ; Potato leaf roll virus ; Virus resistance ; Major gene resistance ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The concentration of potato leaf roll virus (PLRV), as measured by a quantitative enzyme-linked immunosorbent assay, in the foliage of potato plants (Solanum tuberosum) of cv ‘Maris Piper’ with secondary infection was 2900 ng/g leaf, whereas in clones G7445(1) and G7032(5) it was 180 ng/g leaf and 120 ng/g leaf, respectively. To examine the genetic control of resistance to PLRV multiplication, reciprocal crosses were made between the susceptible cultivar ‘Maris Piper’ and the two resistant clones, and the three parents were selfed. Seedling progenies of these families were grown to generate tubers of individual genotypes (clones). Clonally propagated plants were graft-inoculated, and their daughter tubers were collected and used to grow plants with secondary infection in which PLRV concentration was estimated. The expression of resistance to PLRV multiplication had a bimodal distribution in progenies from crosses between ‘Maris Piper’ and either resistant clone, and also in progeny from selfing the resistant parents, with genotypes segregating into high and low virus titre groups. Only the progeny obtained from selfing ‘Maris Piper’ did not segregate, all genotypes being susceptible to PLRV multiplication. The pattern of segregation obtained from these progenies fits more closely with the genetical hypothesis that resistance to PLRV multiplication is controlled by two unlinked dominant complementary genes, both of which are required for resistance, than with the simpler hypothesis that resistance is conferred by a single dominant gene, as published previously.
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  • 45
    ISSN: 1432-2242
    Schlagwort(e): Genetics ; Disease resistance ; Monocots
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An F2 oat population was produced by crossing the diploid (n=7) species Avena strigosa (CI 3815) with A. wiestii (CI 1994), resistant and susceptible, respectively, to 40 isolates of Puccinia coronata, the causal agent of crown rust. Eighty-eight F2 individuals were used to construct an RFLP linkage map representing the A genome of cultivated hexaploid oat. Two hundred and eight RFLP loci have been placed into 10 linkage groups. This map covers 2416 cM, with an average of 12 cM between RFLP loci. Eighty-eight F3 lines, derived from F2 individuals used to construct the map, were screened for resistance to 9 isolates of P. coronata. One locus, Pca, was found to confer a dominant resistance phenotype to isolates 203, 258, 263, 264B, 290, 298, 325A, and 345. Pca also conferred resistance to isolate 276; however, an unlinked second gene may also be involved.
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 89 (1994), S. 313-317 
    ISSN: 1432-2242
    Schlagwort(e): Genetics ; Rice ; Phosphorousefficiency ; Diallel analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The inheritance of phosphorous (P) — deficiency tolerance in rice was investigated by a sevenparent diallel. The parent materials involved were four P-efficient (IR20, IR54, IR28, and Mahsuri), one moderately P-efficient (TN1), and two P-inefficient (IR31406333-1 and IR34686-179-1-2-1), genotypes. Relative tilering ability (RTA) under P-deficient and P-supplemented soil conditions was the parameter used in determining the tolerance level of the different genotypes. Diallel graph analysis revealed that tolerant parents have an excess of recessive genes, while moderate and susceptible parents possess more dominant genes. Genetic-component analysis suggested that both additive and dominance gene effects are involved in the inheritance of P-deficiency tolerance in rice. The trait exhibited over doiminance as confirmed by the graphical analysis. Narrow-sense heritability of the trait was moderate (0.50) and environmental effects were low. Both the general combining ability (GCA) and the specific combining ability (SCA) were significant, but GCA was more prevalent than SCA. Tolerant parents exhibited a high GCA whereas susceptibles have a very poor GCA, suggesting that tolerant parents were mostly enriched in additive genes and susceptible parents in non-additive genes. Crosses involving two high general combiners showed low SCA effects whereas crosses between poor general combiners manifested highly-significant SCA values.
    Materialart: Digitale Medien
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  • 47
    ISSN: 1530-0358
    Schlagwort(e): Desmoids ; Genetics ; Chemotherapy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract PURPOSE: The aim of this study was to describe the natural history and management of surgically unresectable intra-abdominal desmoid tumors in two patients with Gardner's syndrome from two unrelated families, where each had failed on conventional therapy. METHODS: Two patients with Gardner's syndrome were placed on a chemotherapy regimen which included doxorubicin (90 mg/m2) and dacarbazine (900 mg/m2) in divided doses over four days of continuous infusion. Their progress on chemotherapy was assessed by abdominal computerized tomography and laparoscopy. RESULTS: The computerized abdominal tomography scans proved difficult to interpret because of adhesions and matted small bowel resulting from the patients original colectomies. These findings made it difficult to differentiate postoperative changes from residual desmoid tumor. Second-look laparotomy in such patients was contraindicated as this may predispose to further desmoid production. Laparoscopy disclosed a complete response to this chemotherapy. Nevertheless, we had an iatrogenic small bowel perforation in one of these patients. Each patient showed a complete response to chemotherapy. CONCLUSION: Surgical resection remains the first-line treatment of intra-abdominal desmoid tumors. However, doxorubicin/ dacarbazine chemotherapy on a clinical trial basis may be indicated in patients whose intra-abdominal desmoid is unresectable, or who have failed to respond to treatment with hormones (tamoxifen, Toremifene), steroids (prednisone), and nonsteroidal anti-inflammatory agents (Clinoril®; Merck & Co., Inc., West Point, PA).
    Materialart: Digitale Medien
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  • 48
    ISSN: 1437-160X
    Schlagwort(e): Systemic lupus erythematosus ; Recombinant U1-nRNP proteins ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract To investigate a possible involvement of HLA-class II alleles in the genetic predisposition for the formation of anti-U1-nRNP antibody in systemic lupus erythematosus (SLE), genomic DNA of 178 patients was typed for the DRB1, DQA1 and DQB1 alleles using a polymerase chain reaction (PCR) and non-radioactive-oligonucleotide typing. Antibodies against recombinant U1-nRNP proteins (U1-A- U1-C-and 70K-protein) were determined by ELISA. Anti-U1-C antibody was found in 26 (14.7%), anti-U1-A in 34 (19.2%) and anti-70K in 17 (9.6%) patients. A joint occurrence was observed for these antibodies against the recombinant U1-nRNP proteins: anti-U1-C and anti-U1-A antibodies occurred together more frequently than alone and than together with anti-U1-70K antibodies. The frequency of DRB1 * 04 was slightly increased in the patients with anti-U1-C as compared to the patients without anti-U1-C (P〈0.05, Pcorr=n.s., RR=2.4). The DQA1 * 0301 allele, which is in linkage disequilibrium with DRB1 * 04, is found more frequently in anti-U1-C-positive than in antibody-negative patients. The DQB1 * 0303 allele, detected in 12 of 176 SLE patients, was absent in the patients with any of the antibodies against the U1-nRNP proteins. All these deviations may be due to chance alone. We concluded that the presence of antibodies against recombinant U1-nRNP proteins was not significantly associated with any HLA DRB1, DQA1 and DQB1 allele in our group of SLE patients.
    Materialart: Digitale Medien
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  • 49
    ISSN: 1432-1459
    Schlagwort(e): Multiple sclerosis Epidemiology ; Immigrants Environment ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The incidence and prevalence of multiple sclerosis (MS) were compared, controlling for age, in native-born Israelis of different origins and in immigrants to Israel. This comparison was carried out in two populations, countrywide and in Jerusalem. In the countrywide population, ascertainment was based mainly on hospitalizations; it included 252 patients who were native-born and 150 who had immigrated from Africa-Asia (AA immigrants). The 89 MS patients of Jerusalem also included patients diagnosed in outpatient clinics. In native-born Israelis whose father was born in Europe-America (I-EA), the incidence and prevalence of MS were found to be as high as or even higher than that found previously in immigrants from Europe-America. Among native-born Israelis whose father was born in Africa or Asia (I-AA), the yearly age-adjusted incidence and prevalence rates were found to be 1.4- to 1.8-fold higher than among AA immigrants, pointing to environmental factors. The incidence and prevalence rates in the I-EA were 1.2- to 1.6-fold higher than in the I-AA, pointing to genetic factors. These results seem to point to both environmental and genetic factors in the aetiology of MS. Further research is needed, however, to disentangle the genetic factors from possible environmental differences in the two ethnic groups.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurology 241 (1994), S. 487-491 
    ISSN: 1432-1459
    Schlagwort(e): Juvenile absence epilepsy ; Valproate ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Fifteen patients aged 11–25 years (mean 15.37, SD 3.89) suffering from juvenile absence epilepsy are presented. Only 3 (20%) had absences (AS) as the only seizure type, 12 (80%) had associated generalized tonic-clinic seizures (GTCS) and in the remaining 3 with absences and GTCS there was also sporadic myoclonus. We found a higher frequency of AS in our patients by clinical history and video-EEG than has been previously reported. In our patients the mean age of onset in years was 11.4, SD 1.24 for AS, 13.12, SD 2.31 for GTCS and 12.5, SD 2.18 for myoclonus. The correct diagnosis was not made on referrals for any of the patients. It took an average of 3–5.5 years from the onset of the AS (range: 6–120 months) and 2 years from the occurrence of GTCS (average: 1–72 months) to make the correct diagnosis and institute proper treatment, which was valproic acid (VPA). The GTCS were controlled in all patients whereas AS continued in 6 (40%), but to a significantly lesser degree. The frequency and the duration of the GTCS before the start of VPA treatment seemed to have an adverse effect on AS control. We documented no circadian rhythm in either AS or the GTCS, except in 2 patients who had AS and GTCS mainly when they awoke in the morning. The sample size was too small to perform a proper genetic study, though a positive history of epilepsies of mixed types was obtained in 35.7% of the parents and the siblings of the probands.
    Materialart: Digitale Medien
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    European archives of psychiatry and clinical neuroscience 244 (1994), S. 138-140 
    ISSN: 1433-8491
    Schlagwort(e): Parity ; Genetics ; Diathesis-stress model
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract As part of a follow-up and family study of post-partum psychoses, this episode of illness being the first leading to psychiatric hospitalisation, patients with puerperal episodes (PE) and nonpuerperal episodes (NPE) of illness in the long-term course (n=79) were compared to patients with PE only (n=40). Few differences were found. Relatives of patients with PE only had a lower morbidity risk for functional psychoses than relatives of patients with PE and NPE. A favourable course of illness in the presence of a low genetic predisposition may be expected, according to the diathesis-stress model of functional psychoses.
    Materialart: Digitale Medien
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    European journal of epidemiology 10 (1994), S. 317-324 
    ISSN: 1573-7284
    Schlagwort(e): Epidemiology ; Genetics ; Oral clefts ; Registers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Epidemiological and genetic variables for oral clefts were analysed for the years 1981–1989 in a case-control study of congenital malformations in the Emilia Romagna, Veneto, and Friuli regions, and in the Trento and Bolzano hospitals. Birth prevalence for all cases of cleft lip with or without cleft palate (CL(P)) was 8.2 per 10,000 births, and that for cleft palate only (CP) was 6.1 per 10,000. Coexisting abnormalities were found in 23% of CL(P) cases and in 43% of CP. No clusters in time or space were detected. For isolated clefts, a predominance of males among CL(P) and of females among CP was found; epilepsy was the only maternal risk factor correlated with clefts, and an association between clefting and consanguinity was found. Empirical recurrence risks were calculated in both isolated CL(P) and CP.
    Materialart: Digitale Medien
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  • 53
    ISSN: 1432-2242
    Schlagwort(e): Maize ; Restriction fragment length polymorphisms (RFLPs) ; Qualitative and quantitative inheritance ; Plant breeding ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Restriction fragment length polymorphisms (RFLPs) and one morphological marker were used to investigate quantitative trait loci (QTL) for morphological and physiological traits evaluated on 150 F2∶3 maize (Zea mays L.) lines derived from the cross of elite U.S. Corn Belt inbreds Mo17 and H99. F2∶3 lines were grown in a replicated experiment and evaluated for plant and ear heights and flowering traits. QTL were identified for each trait, and genetic effects were determined. Estimated gene action for the flowering traits was predominantly overdominance. Both parents contributed toward increased values for anthesis and silk emergence. QTL for increased plant and ear heights were usually contributed by the taller parent, Mo17. Estimated gene action for these traits was mainly partial to overdominance. QTL for plant height were located in the vicinity of loci defined by alleles with qualitative effects on plant height.
    Materialart: Digitale Medien
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  • 54
    ISSN: 1617-4623
    Schlagwort(e): Gene regulation ; Ribozyme ; npt-gene ; Transgenic tobacco ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A chimeric gene encoding a ribozyme under the control of the cauliflower mosaic virus (CaMV) 35S promoter was introduced into transgenic tobacco plants. In vivo activity of this ribozyme, which was designed to cleave npt mRNA, was previously demonstrated by transient expression assays in plant protoplasts. The ribozyme gene was transferred into transgenic tobacco plants expressing an rbcS-npt chimeric gene as an indicator. Five double transformants out of sixteen exhibited a reduction in the amount of active NPT enzyme. To measure the amount of ribozyme produced, in the absence of its target, the ribozyme and target genes were separated by genetic segregation. The steady-state concentrations of ribozyme and target RNA were shown to be similar in the resulting single transformants. Direct evidence for a correlation between reduced npt gene expression and ribozyme expression was provided by crossing a plant containing only the ribozyme gene with a transgenic plant expressing the npt gene under control of the 35S promoter, i.e. the same promoter used to direct ribozyme expression. The expression of npt was reduced in all progeny containing both transgenes. Both steady-state levels of npt mRNA and amounts of active NPT enzyme are decreased. In addition, our data indicate that, at least in stable transformants, a large excess of ribozyme over target is not a prerequisite for achieving a significant reduction in target gene expression.
    Materialart: Digitale Medien
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Behavioral ecology and sociobiology 35 (1994), S. 99-107 
    ISSN: 1432-0762
    Schlagwort(e): Key words Apis mellifera ; Genetics ; Drone production ; Allozymes ; Reproductive conflict
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Previously we reported that there are subfamily differences in drone production in queenless honey bee colonies, but these biases are not always explained by subfamily differences in oviposition behavior. Here we determine whether these puzzling results are best explained by either inadequate sampling of the laying worker population or reproductive conflict among workers resulting in differential treatment of eggs and larvae. Using colonies composed of workers from electrophoretically distinct subfamilies, we collected samples of adult bees engaged in the following behavior: “true” egg laying, “false” egg laying, indeterminate egg laying, egg cannibalism, or nursing (contact with larvae). We also collected samples of drone brood at four different ages: 0 to 2.5-h-old eggs, 0 to 24-h-old eggs, 3 to 8-day-old larvae, and 9 to 14-day-old larvae and pupae. Allozyme analyses revealed significant subfamily differences in the likelihood of exhibiting egg laying, egg cannibalism, and nursing behavior, as well as significant subfamily differences in drone production. There were no subfamily differences among the different types of laying workers collected from each colony, suggesting that discrepancies between subfamily biases in egg-laying behavior and drone production are not due to inadequate sampling of the laying worker population. Subfamily biases in drone brood production within a colony changed significantly with brood age. Laying workers had significantly more developed ovaries than either egg cannibals or nurses, establishing a physiological correlate for the observed behavioral genetic differences. These results suggest there is reproductive conflict among subfamilies and individuals within queenless colonies of honey bees. The implications of these results for the evolution of reproductive conflict, in both queenright and queenless contexts, are discussed.
    Materialart: Digitale Medien
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Metabolic brain disease 9 (1994), S. 105-131 
    ISSN: 1573-7365
    Schlagwort(e): Alcoholism ; Genetics ; Endorphins ; Enkephalins ; Dynorphins ; Opioid ; Receptors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract At the present time alcoholism is recognized as a metabolic disease exhibiting the clinical features of craving for alcohol, loss of control over drinking, tolerance and physical dependence on alcohol, while both epidemiological and experimental studies have demonstrated that genetic factors may be important in determining whether an individual has a high or low vulnerability to develop alcoholism. Evidence also indicates that alcoholism is not characterized by a single gene single allele inheritance. Instead it seems that multiple genes and environmental factors interact to increase or decrease an individual's vulnerability to become an alcoholic. Current research is aimed at investigating whether certain behavioral, physiological and biochemical markers are highly associated with the incidence of alcoholism. Among the biochemical markers currently under investigation is the endogenous opioid system and its implication in mediating the reinforcing effects of ethanol. It is the objective of this manuscript to review current research on: (a) the interactions of ethanol with the endogenous opioid system at the molecular level; (b) the existence of genetically determined differences in the response of the endogenous opioid system to ethanol between subjects at high and low risk for excessive ethanol consumption, as well as between lines of animals showing preference or aversion for ethanol solutions; (c) the decrease of alcohol consumption following pretreatment with opioid antagonists; and (d) the possible use of specific opioid receptor antagonists together with behavioral therapy to modify drinking behavior, to control craving and to prevent relapse.
    Materialart: Digitale Medien
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Behavioral ecology and sociobiology 34 (1994), S. 117-409 
    ISSN: 1432-0762
    Schlagwort(e): Social insects ; Apis mellifera ; Division of labor ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Variability exists among worker honey bees for components of division of labor. These components are of two types, those that affect foraging behavior and those that affect life-history characteristics of workers. Variable foraging behavior components are: the probability that foraging workers collect (1) pollen only; (2) nectar only; and (3) pollen and nectar on the same trip. Life history components are: (1) the age the workers initiate foraging behavior; (2) the length of the foraging life of a worker; and (3) worker length of life. We show how these components may interact to change the social organization of honey bee colonies and the lifetime foraging productivity of individual workers. Selection acting on foraging behavior components may result in changes in the proportion of workers collecting pollen and nectar. Selection acting on life-history components may affect the size of the foraging population and the distribution of workers between within nest and foraging activities. We suggest that these components define possible sociogenic “pathways” through which colony-level natural selection can change social organization. These pathways may be analogous to developmental pathways in the morphogenesis of individual organisms because small changes in behavioral or life history components of individual workers may lead to major changes in the organizational structure of colonies.
    Materialart: Digitale Medien
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Behavioral ecology and sociobiology 35 (1994), S. 99-107 
    ISSN: 1432-0762
    Schlagwort(e): Apis mellifera ; Genetics ; Drone production ; Allozymes ; Reproductive conflict
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Previously we reported that there are subfamily differences in drone production in queenless honey bee colonies, but these biases are not always explained by subfamily differences in oviposition behavior. Here we determine whether these puzzling results are best explained by either inadequate sampling of the laying worker population or reproductive conflict among workers resulting in differential treatment of eggs and larvae. Using colonies composed of workers from electrophoretically distinct subfamilies, we collected samples of adult bees engaged in the following behavior: “true” egg laying, “false” egg laying, indeterminate egg laying, egg cannibalism, or nursing (contact with larvae). We also collected samples of drone brood at four different ages: 0 to 2.5-h-old eggs, 0 to 24-h-old eggs, 3 to 8-day-old larvae, and 9 to 14-day-old larvae and pupae. Allozyme analyses revealed significant subfamily differences in the likelihood of exhibiting egg laying, egg cannibalism, and nursing behavior, as well as significant subfamily differences in drone production. There were no subfamily differences among the different types of laying workers collected from each colony, suggesting that discrepancies between subfamily biases in egg-laying behavior and drone production are not due to inadequate sampling of the laying worker population. Subfamily biases in drone brood production within a colony changed significantly with brood age. Laying workers had significantly more developed ovaries than either egg cannibals or nurses, establishing a physiological correlate for the observed behavioral genetic differences. These results suggest there is reproductive conflict among subfamilies and individuals within queenless colonies of honey bees. The implications of these results for the evolution of reproductive conflict, in both queenright and queenless contexts, are discussed.
    Materialart: Digitale Medien
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Behavioral ecology and sociobiology 34 (1994), S. 125-137 
    ISSN: 1432-0762
    Schlagwort(e): Social insects ; Apis mellifera ; Division of labor ; Genetics ; Nepotism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Three experiments were performed to determine whether brood care in honey bee colonies is influenced by colony genetic structure and by social context. In experiment 1, there were significant genotypic biases in the relative likelihood of rearing queens or workers, based on observations of individually labeled workers of known age belonging to two visually distinguishable subfamilies. In experiment 2, no genotypic biases in the relative likelihood of rearing drones or workers was detected, in the same colonies that were used in experiment 1. In experiment 3, there again were significant genotypic differences in the likelihood of rearing queens or workers, based on electrophoretic analyses of workers from a set of colonies with allozyme subfamily markers. There also was an overall significant trend for colonies to show greater subfamily differences in queen rearing when the queens were sisters (half- and super-sisters) rather than unrelated, but these differences were not consistent from trial to trial for some colonies. Results of experiments 1 and 3 demonstrate genotypic differences in queen rearing, which has been reported previously based on more limited behavioral observations. Results from all three experiments suggest that genotypic differences in brood care are influenced by social context and may be more pronounced when workers have a theoretical opportunity to practice nepotism. Finally, we failed to detect persistent interindividual differences in bees from either subfamily in the tendency to rear queen brood, using two different statistical tests. This indicates that the probability of queen rearing was influenced by genotypic differences but not by the effect of prior queen-rearing experience. These results suggest that subfamilies within a colony can specialize on a particular task, such as queen rearing, without individual workers performing that task for extended periods of time.
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  • 60
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 1-11 
    ISSN: 0749-503X
    Schlagwort(e): Schizosaccharomyces pombe ; Golgi body ; protein transport ; secretion ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Schizosaccharomyces pombe was treated with either cycloheximide or anisomycin at levels sufficient to inhibit 〉95% of protein synthesis for periods upon to 3 h, equivalent to one cell cycle. Treatment for as little as 1 h caused significant loss of the Golgi apparatus by both immunofluorescence and electron microscopy. The loss was quantitated by stereology on electron micrographs. Nearly 90% of the stacked Golgi was lost over a 3 h period. No other intracellular membrane compartment seemed to be affected. Measurement of enzyme activities confirmed these observations. The activity of a resident of the Golgi apparatus, α-1,2 galactosyltransferase, was reduced over this time, whereas the endoplasmic reticulum marker, BiP, and the cytoplasmic enzyme, hexokinase, were unaffected. The morphological changes associated with cycloheximide addition were reversed on its removal, though there was a lag before cells recommenced growth or secretion of the enzyme, acid phosphatase.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 61
    ISSN: 0749-503X
    Schlagwort(e): Genome sequencing ; Saccharomyces cerevisiae ; chromosome XI ; MBR1 ; GTPase-activating protein ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We present the DNA sequence analysis of a region covering a 3·5 kb EcoRI fragment from the left arm of chromosome XI from Saccharomyces cerevisiae. This region contains five open reading frames (ORFs) which code for proteins of greater than 100 amino acids. ORF YKL425 codes for the previously sequenced Mbr1 (Valens et al., 1991; Daignan-Fornier et al., 1993) which participates in mitochondrial biogenesis. YKL424 has identity with a GTPase-activating protein of higher eukaryotes. The three remaining ORFs have no identity to known proteins within the databases screened and are not assigned ORF numbers as they are completely contained with ORFs YKL424 and YKL425. This sequence has been entered in the EMBL Data Library under Accession Number X75561.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 62
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994) 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 63
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 29-38 
    ISSN: 0749-503X
    Schlagwort(e): Heterologous gene expression ; levansucrase precursor ; Bacillus subtilis ; yeast ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Levansucrase, a Bacillus subtilis extracellular enzyme, was not secreted in the culture medium when produced in yeast. The protein accumulated inside the cell in its precursor form which represented 0·3% of total proteins. The absence of any post-translational modifications, such as signal sequence cleavage or addition of N-linked sugars, indicated that this protein did not enter the reticulum secretion pathway.Direct observation of the cells by confocal laser scanning microscopy showed that levansucrase was associated with the cytoplasmic membrane. Subcellular fractionation experiments revealed that levansucrase precursor form is associated with membranes through weak ionic interactions. The purified precursor displayed the same catalytic properties as levansucrase secreted by B. subtilis. Thus yeast could be used as a source of levansucrase precursor allowing its isolation as a pure form on a milligram scale.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 64
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 271-274 
    ISSN: 0749-503X
    Schlagwort(e): Genome sequencing ; Saccharomyces cerevisiae ; chromosome III ; telomeres ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A comparison of the sequences of telomere regions from several yeast chromosomes revealed an apparent cloning artifact for the right end of chromosome III. An integrating vector containing G1-3T telomere sequences was used to clone the right end of chromosome III from a strain related to S288C. The sequence of this clone confirmed that the published sequence was incorrect and demonstrated that the right telomere region of chromosome III is similar to other telomeres.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 65
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; Saccharomyces douglasii ; evolution ; ARG4 ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A 3·6 kb DNA fragment from Saccharomyces douglasii, containing the ARG4 gene, has been cloned, sequenced and compared to the corresponding region from Saccharomyces cerevisiae. The organization of this region is identical in both yeasts. It contains besides the ARG4 gene, another complete open reading frame (ORF) (YSD83) and a third incomplete one (DED81). The ARG4 and the YSD83 coding regions differ from their S. cerevisiae homologs by 8.1% and 12·5%, respectively, of base substitutions. The encoded proteins have evolved differently: amino acid replacements are significantly less frequent in Arg4 (2·8%) than in Ysc83 (12·4%) and most of the changes in Arg4 are conservative, which is not the case for Ysc83. The non-coding regions are less conserved, with small AT-rich insertions/deletions and 20% base substitutions. However, the level of divergence is smaller in the aligned sequences of these regions than in silent sites of the ORFs, probably revealing a higher degree of constraints. The Gcn4 binding site and the region where meiotic double-strand breaks occur, are fully conserved. The data confirm that these two yeasts are evolutionarily closely related and that comparisons of their sequences might reveal conserved protein and DNA domains not expected to be found in sequence comparisons between more diverged organisms.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 371-376 
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; NES24 ; chromosome XIII ; neomycin ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have cloned NES24 using a temperature-sensitive nes24-1 mutant as a host and sequenced a 3162 bp XhoI-EcoRI DNA fragment containing the NES24 gene. Computer analysis revealed that this segment contains a 1806 bp open reading frame which is needed for complementation of the nes24-1 mutation. We found SUP8 in the region upstream of the NES24 gene, placing the NES24 gene on chromosome XIII. A protein homology search indicated that NES24 encodes a new protein. The disruption of the NES24 gene resulted in temperature-sensitive growth. The sequence has been deposited in DDBJ/EmBL/GenBank data bases under Accession Number D15052.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 67
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 399-402 
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; Chromosome V ; Monomeric G-protein ; Rab protein ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A Saccharomyces cerevisiae sequence cloned by serendipity was found to encode a protein that is a new member of the Ypt/Rab monomeric G-protein family. This sequence shows high homology to the yeast genes SEC4 and YPT1 and, like SEC4 and YPT1, is essential for viability. The sequence was localized to chromosome V based upon hybridization to pulse-field gel-separated yeast chromosomes. The sequence has been deposited in the GenBank data library under Accession Number L17070.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 68
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994) 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 69
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 451-461 
    ISSN: 0749-503X
    Schlagwort(e): RAS-cAMP pathway ; CDC25 family ; cell division cycle mutation ; S. cerevisiae ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have identified MS12 as a gene of Saccharomyces cerevisiae which, when on a multicopy vector, suppresses the heat shock sensitivity caused by the loss of the IRA1 product, a negative regulator of the RAS protein. The multicopy MSI2 also suppresses the heat shock sensitivity of cells with the RAS2val19 mutation but not those with the bcy1 mutation, suggesting that the MSI2 protein may interfere with the activity of the RAS protein. The sequence analysis of MSI2 reveals that it is identical to LTE1 belonging to the CDC25 family: CDC25, SCD25 and BUD5, each of which encodes a guanine nucleotide exchange factor for the ras superfamily gene products. Deletion of the entire MSI2 coding region reveals that MSI2 is not essential but the disruptant shows a cold-sensitive phenotype. Under the non-permissive conditions, more than 70% of the msi2 disruptants arrested at telophase as large budded cells with two nuclei divided completely and elongated spindles, indicating that the msi2 deletion is a cell division cycle mutation. These results suggest that MSI2 is involved in the termination of M phase and that this process is regulated by a ras superfamily gene product.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 70
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 463-474 
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; cell polarity ; cellular morphogenesis ; GTPases ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Cdc24p and Cdc42p are involved in the control of cell polarity during the Saccharomyces cerevisiae cell cycle. Cdc42p is a member of the Ras superfamily of GTPases and Cdc24p displays limited amino-acid sequence similarity with the Dbl proto-oncoprotein, which acts to stimulate guanine-nucleotide exchange on human Cdc42p. We have performed several genetic experiments to test whether Cdc24p and Cdc42p interact within the cell. First, overexpression of Cdc24p suppressed the dominant-negative cdc42D118A allele. Second, overexpression of wild-type CDC24 and CDC42 genes together was a lethal event resulting in a morphological phenotype of large, round, unbudded cells, indicating a loss of cell polarity. Third, a cdc24ts cdc42ts double mutant exhibited a synthetic-lethal phenotype at the semi-permissive temperature of 30°C. These data suggest that Cdc24p and Cdc42p interact within the cell and that Cdc24p may be involved in the regulation of Cdc42p activity.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 71
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 497-508 
    ISSN: 0749-503X
    Schlagwort(e): Protein secretion and processing ; gene expression ; killer toxin ; Kex2 protease ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: K1 preprotoxin is the 316 residue precursor of the K1 killer toxin secreted by the yeast Saccharomyces cerevisiae. The SPβla reporter consists of the mature, secreted form of β-lactamase (βla) fused to S and P, two fragments of preprotoxin. S is the N-terminal 34 residues, including the secretion signal. P, a 67 residue ‘processing’ segment with three sites for N-glycosylation, terminates in a Lys Arg site for cleavage by the Kex2 protease. Expression of SPβla in yeast results in efficient secretion, processing by signal peptidase and glycosylation in the endoplasmic reticulum, producing proßla. Kex2 cleavage of proßla in the lumen of a late Golgi compartment releases βla, which accumulates stably in culture media buffered at pH 5·8-7. The half-life of secretion is 11 min at 30°C; 10-12% of the total activity in exponential-phase cells is intracellular, mostly in the form of proßla, indicating that transit from the endoplasmic reticulum to the Golgi is rate limiting. We have used SPβla expression in single- and multi-copy vectors to compare the PGK, GAL1, GAL10, PHO5 and CUP1 promoters under varying nutritional conditions. In exponential-phase cells, secretion of βla over a 40-fold range and up to several μg/ml was proportional to transcript level, demonstrating that SPβla can be employed as a convenient secreted reporter of promoter function in yeast.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 72
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 415-415 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 73
    ISSN: 0749-503X
    Schlagwort(e): Yeast ; fungi ; zymocin ; promoter ; pGKL1 ; pGKL2 ; pSKL ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The toxin-encoding linear plasmid systems found in Pichia acaciae and Kluyveromyces lactis yeasts appear to be quite similar, both in function and structural organization. By Southern hybridization, a linear plasmid of P. acaciae, pPac1-2, was found to hybridize to the second open reading frame (ORF2) of K. lactis plasmid pGKL1, known to encode the α and β subunits of the K. lactis toxin. A 1·7 kbp segment of pPac1-2 DNA was cloned, sequenced and shown to contain four regions of strong homology to four similarly oriented regions of K. lactis ORF2. This 1·7 kbp fragment also contained an ORF of 1473 bp that could encode a protein of ∼ 55·8 kDa. Like the α subunit gene of K. lactis ORF2, a very hydrophobic region occurs at the N-terminus, perhaps representing a signal sequence for transport out of the cell. Unlike K. lactis ORF2, however, the encoded polypeptide is much smaller and lacks a recognizable domain common to chitinases. The structure of a toxin that includes the translation product of this P. acaciae ORF would likely be quite different from that of the K. lactis toxin. Analysis of the upstream region of the P. acaciae ORF revealed an upstream conserved sequence identical to that found before ORFs 8 and 9 of pGKL2. A possible hairpin loop structure, as has been described for each of the four K. lactis pGKL1 ORFs, was found just upstream of the presumed start codon. The similarity of the promoter-like elements found in the linear plasmid genes of these diverse yeasts reinforces the idea of the existence of a unique, but highly conserved, expression system for these novel plasmids. The sequence has been deposited in the GenBank data library under Accession Number U02596.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 74
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 491-496 
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; ARS1 ; DNA replication, mitotic ; DNA replication, premeiotic ; plasmid integration ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have investigated the significance of the chromosomal replication origin, ARS1, during the entire life cycle of yeast. This was done by substituting the chromosomal copy with a series of ars1 deletion mutants. It was shown that the ARS1 replication origin is not essential for mitotic or premeiotic DNA replication since no effect on growth, chromosomal loss rate and spore viability was observed in the ars1 mutant strains. We conclude that replication origins are abundantly, present in the yeast genome and that the removal of a single replication origin is compensated for by replication forks emanating from neighbouring origins.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 75
    ISSN: 0749-503X
    Schlagwort(e): Mitochondrial carriers ; duplication ; citrate synthase ; RNA binding ; ribosomes ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A 15·1 kb fragment of the yeast genome was allocated to the centromeric region of chromosome XIV by genetic mapping. It contained six bona fide genes, RPC34, FUN34, CIT1 (Suissa et al., 1984), RLP7, PET8 and MRP7 (Fearon and Mason, 1988) and two large open reading frames, DOM34 and TOM34, RPC34 and RLP7 define strictly essential functions, whereas CIT1, PET8 and MRP7 encode mitochondrial proteins. The PET8 product belongs to a family of mitochondrial carrier proteins. FUN34 encodes a putative transmembraneous protein that is non-essential as judged from the normal growth of the fun34-::L̈K18 (URA3) allele, even on respirable substrates. TOM34 codes for a putative RNA binding protein, and DOM34 defines a hypothetical polypeptide of 35 kDa, with no significant homology to known proteins. The region under study also contains two divergently transcribed tDNAs, separated only by a chimeric transposable element. This tight tDNA linkage pattern is commonly encountered in yeast, and a general hypothesis is proposed for its emergence on the Saccharomyces cerevisiae genome. RPC34, RLP7, PET8 and MRP7 are unique on the yeast genome, but the remaining genes belong to an extant centromeric duplication between chromosome III and XIV. The sequences have been deposited in the EMBL/GenBank data libraries under Accession Numbers L11277, L19167, M11344, M22116, V02536, X00782 and X63746.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 76
    ISSN: 0749-503X
    Schlagwort(e): Random-breakage mapping ; yeast ; APN1 ; YUH1 ; chromosome XI ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have used the previously described technique of random-breakage mapping to locate the two yeast genes APN1 and YUH1. The APN1 locus is located ∼235 kb from the left telomere of chromosome XI, and shows weak (∼53 cM) genetic linkage to ura1. The YUH1 locus is located ∼140 kb from the right telomere of chromosome X, and genetically maps 3·6 cM distal to cdc11. In addition, we show by random-breakage mapping that TRP3 is located ∼45 kb from the left telomere of chromosome XI, whereas FAS1 is ∼110 kb from the same telomere. This supports a gene order on the left distal portion of chromosome XI that agrees with other physical reports but is inverted with respect to Edition 11 of the published genetic map. This report confirms that random-breakage mapping is a rapid and convenient method of locating cloned genes.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 557-557 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 653-657 
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; basic-amino-acid permease ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A Saccharomyces cerevisiae gene (1722 bp), encoding a protein (574 aa) highly homologous to the basic-amino-acid permeases LYP1 and CAN1, was sequenced. The gene, which was named APL1 (Amino-acid Permase Like), is located 881 bp upstream from LYP1 (lysine-specific permease), and in head-to-head orientation to it. These sequence data have been deposited in the EMBL/GenBank/DDBJ nucleotide sequence data libraries under Accession Number X74069.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 79
    ISSN: 0749-503X
    Schlagwort(e): Genome sequencing ; Saccharomyces cerevisiae ; chromosome XI ; catabolic threonine dehydratase ; membrane transporter ; hydantoinase ; phospholipase A2-activating protein ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We report the entire sequence of a 26·4 kb segment of chromosome XI of Saccharomyces cerevisiae. Identification of the known loci URA1, TRP3 and SAC1 revealed a translocation compared to the genetic map. Additionally, six unknown open reading frames have been identified. One of them is similar to catabolic threonine dehydratases. Another one contains characteristic features of membrane transporters. A third one is homologous in half of its length to the prokaryotic hydantoinase HyuA and in the other half to hydatoinase HyuB. A fourth one is homologous to the mammalian phospholipase A2-activating protein. A fifth one, finally, is homologous to the hypothetical open reading frame YCR007C of chromosome III. The sequence has been deposited in the EMBL data library under Accession Number X75951.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 80
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 701-708 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 81
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. ii 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 82
    ISSN: 0749-503X
    Schlagwort(e): Yeast ; adenylate cyclase ; Ras ; Kluyveromyces marxianus ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The presence of adenylate cyclase activity was first demonstrated in membrane fractions from the budding yeast Kluyveromyces marxianus. The enzyme showed a Mn2+- and Mg2+-dependent activity, with optimal pH at around 6 as observed in other yeast species. As in Saccharomyces cerevisiae, where adenylate cyclase is regulated by RAS1 and RAS2, we detected a guanyl nucleotide-dependent activity. Interestingly Y13-259 monoclonal antibody, raised against mammalian p21Ha-ras, inhibited Mg2+ plus GTP-γ-S-dependent cAMP production, suggesting that the GTP binding proteins involved in adenylate cyclase regulation could be Ras proteins. The same antibody recognized on Western blot and immunoprecipitated a 40 kDa polypeptide from K. marxianus crude membranes. This polypeptide was not detected by an anti-RAS2 polyclonal antibody raised against S. cerevisiae RAS2 protein, suggesting that Ras proteins from the two species could be structurally different.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 83
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 709-717 
    ISSN: 0749-503X
    Schlagwort(e): Ribosomal DNA spacers ; oligonucleotide probes ; Candida albicans ; rapid yeast identification ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: In order to develop DNA probes for rapid, sensitive and specific detection of the pathogenic yeast species Candida albicans, we carried out comparative sequence analysis of the two internal transcribed spacer regions (ITS1 and ITS2) of the ribosomal DNA (rDNA) units of C. albicans and the closely related pathogenic species C. tropicalis. While overall sequence similarity between the two species was considerable (65-75%), both ITS1 and ITS2 were found to contain distinct regions with sufficient sequence divergence to make them suitable as specific target sites for the identification of C. albicans. On the basis of these results one ITS1-derived (ANAB1) and two ITS2-derived (ANAB2 and ANAB3) oligonucleotides were selected, chemically synthesized, and used as hybridization probes. Their specificity and reliability were evaluated in dot-blot hybridization experiments with total genomic DNA from 13 strains of medically important Candida species, six strains of other yeast genera associated with man and animals, and ten strains previously identified as C. albicans by phenotypic criteria. Under well-defined hybridization conditions the three probes hybridized exclusively with DNA derived from strains belonging to the species C. albicans, thus demonstrating their potential clinical usefulness. The failure of four of the (presumed) C. albicans strains to show hybridization to the ITS probes sheds doubt upon their taxonomic classification, which is reinforced by other phenotypic aspects of these strains.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 84
    ISSN: 0749-503X
    Schlagwort(e): Poly(ADP-ribose) polymerase ; fission yeast ; cell cycle ; DNA repair ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The activity of poly(ADP-ribose) polymerase (PADPRP), a chromatin-associated enzyme present in most eukaryotic cells, is stimulated by DNA strand breaks, suggesting a role for the enzyme in the cellular response to DNA damage. However, the primary function of PADPRP remains unknown. We have selected Schizosaccharomyces pombe as a simple eukaryotic system in which to study PADPRP function because this fission yeast shares with mammalian cells important cellular features possibly associated with poly-(ADP-ribos)ylation pathways. We investigated the existence of an endogenous yeast PADPRP by DNA and RNA hybridization to mammalian probes under low-stringency conditions and by PADPRP activity assays. Our data indicate that fission yeasts are naturally devoid of PADPRP. We therefore isolated S. pombe strains expressing PADPRP by transformation with a human full-length PADPRP cDNA under the control of the SV40 early promoter. The human PADPRP construct was transcribed and translated in S. pombe, generating a major transcript of the same size (3.7 kb) as that detected in mammalian cells and a 113-kDa polypeptide, identical in size to the native human PADPRP protein. Yeast recombinant PADPRP was enzymatically active and was recognized by antibodies to human PADPRP. S. pombe cells expressing PADPRP (SPT strains) showed a stable phenotype that was characterized by: (i) cell cycle retardation as a result of a specific delay at the G1 phase, (ii) decreased cell viability in stationary cultures, (iii) enhanced rates of spontaneous and radiation-induced ade6-ade7 mutations, and (iv) increased sensitivity to radiation. SPT strains may prove efficient tools with which to investigate PADPRP functions in eukaryotic cells.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 1075-1082 
    ISSN: 0749-503X
    Schlagwort(e): Schizosaccharomyces pombe ; thiamine ; transcription ; inducible promoter ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We previously described a screen for thiamine-repressible genes in Schizosaccharomyces pombe and reported on one such gene, nmt1, required for thiamine biosynthesis. Here we describe a second gene, nmt2, recovered in the same screen. Disruption of nmt2 also resulted in thiamine auxotrophy, indicating a role for the nmt2 gene product in thiamine biosynthesis. Both genes are highly transcribed in minimal medium and repressed in medium containing thiamine, and nuclear ‘run-on’ experiments confirm that expression in both cases is controlled by the rate of transcription initiation. The virtually identical kinetics of induction and repression suggest that the two genes are co-ordinately regulated. Sequence comparison of the two promoters reveals a canonical TATA box, downstream of which is a perfectly conserved 11 bp element. Transcript mapping experiments show that transcription initiation of both genes is centred on this element.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 86
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; sulphite resistance ; gene cloning and sequencing ; SUL1 ; zinc-finger protein ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: In this paper we describe the cloning and sequencing of the gene (SUL1) responsible for sulphite resistance in a Saccharomyces cerevisiae mutant (Casalone et al., 1992). The deduced amino acid sequence predicted that the gene codes for a zinc-finger protein with five fingers. Comparison of wild-type and mutant gene sequences demonstrated that the mutation event was a transversion from C to G; as a consequence of the mutation a histidine substituted an aspartic acid, affecting directly the fourth finger structure. The SUL1 gene sequence corresponds to that of FZF1 gene (Breitwieser et al., 1993) to which no function was attributed. The sequence has been entered in the EMBL data library under Accession Number 77592.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 1157-1171 
    ISSN: 0749-503X
    Schlagwort(e): rDNA ; ribosomal DNA ; rDNA clusters ; chromosomes ; pulsed-field gel electrophoresis ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Several recent investigations, employing restriction endonucleases that do not cleave within rDNA units, revealed that a number of laboratory strains of Saccharomyces cerevisiae apparently contain a single tandem array of approximately 50 to 200 rDNA units on each chromosome XII homolog. The number of these rDNA units varies from strain to strain, among subclones of the same strain, and after different conditions of growth. In contrast, the commonly-used strain S288C and its derivatives contain two clusters on each chromosome XII homolog. Although the two clusters are stably maintained, the number of rDNA units within each cluster can vary as in strains with single clusters.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 1211-1216 
    ISSN: 0749-503X
    Schlagwort(e): Actin ; cytoskeleton ; SAC2 ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A temperature-sensitive mutation (act1-1) in the essential actin gene of Saccharomyces cerevisiae can be suppressed by mutations in the SAC2 gene. A cloned genomic DNA fragment that complements the cold-sensitive growth phenotype associated with such a suppressor mutation (sac2-1) was sequenced. The fragment contained an open reading frame that encodes a 641 amino acid predicted hydrophilic protein with a molecular weight of 74 445. No sequences with significant similarity to SAC2 were found in the GenBank and EMBL databases. A SAC2 disruption mutation was constructed which had phenotypes similar to the sac2-1 point mutation. A haploid SAC2 disruption strain failed to grow at low temperature and the disruption allele suppressed the temperature-sensitive act1-1 growth defect. The suppression phenotype was dependent on the strain background. The SAC2 sequence has been submitted to the EMBL data library (Accession Number Z29988).
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 89
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; genomic sequencing ; chromosome II ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A 3·2 kb EcoRI fragment of yeast Saccharomyces cerevisiae was entirely sequenced. Two new open reading frames were identified. The first is extremely hydrophobic, and would likely be an integral membrane protein. It has significant similarity to only one reported gene, a gene of unknown function from Drosophila melanogaster. The second ORF is asparagine-rich and very serine-rich, with a remarkable stretch of nearly 26 consecutive asparagine residues comprised of the same codon. It has no significant similarity to any reported gene. The fragment maps to chromosome II on the left arm between the CDC27 and ILS1 loci. The nucleotide sequence reported in this paper has been deposited in the GenBank database with the Accession Number M89908.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 90
    ISSN: 0749-503X
    Schlagwort(e): Yeast ; chromosome XIV ; citrate synthase ; FUN34 ; PRP2 ; RPC34 ; SIS1 ; URK1 ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The nucleotide sequence of 23·6 kb of the right arm of chromosome XIV is described, starting from the centromeric region. Both strands were sequenced with an average redundancy of 4·87 per base pair. The overall G+C content is 38·8% (42·5% for putative coding regions versus 29·4% for non-coding regions). Twelve open reading frames (ORFs) greater than 100 amino acids were detected. Codon frequencies of the twelve ORFs agree with codon usage in Saccharomyces cerevisiae and all show the characteristics of low level expressed genes. Five ORFs (N2019, N2029, N2031, N2048 and N2050) are encoded by previously sequenced genes (the mitochondrial citrate synthase gene, FUN34, RPC34, PRP2 and URK1, respectively). ORF N2052 shows the characteristics of a transmembrane protein. Other elements in this region are a tRNAPro gene, a tRNAAsn gene, a τ34 and a truncated δ34 element. Nucleotide sequence comparison results in relocation of the SIS1 gene to the left arm of the chromosome as confirmed by colinearity analysis. The nucleotide sequence data reported in this paper will appear in the EMBL, GenBank and DDBJ Nucleotide Sequence Databases under the accession number X77395.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 91
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 1389-1394 
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; yeast ; AAA-protein family ; putative ATPase ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A nuclear gene from Saccharomyces cerevisiae was cloned by genetic complementation of a temperature-sensitive respiratory-deficient mutant. DNA sequence analysis reveals that it encodes a protein with homology to Yme1, FtsH and Tma, proteins which belong to the AAA-protein family (ÃPases associated with diverse cellular activities). The members of this family are involved in very different biological processes. Yme1p, a yeast mitochondrial protein, affects the rate of DNA escape from mitochondria to the nucleus and the Escherichia coli FtsH protein is apparently involved in the post-translational processing of PBP3, a protein necessary for septation during cell division. This newly sequenced gene, which we have designated AFG3 for ÃPase family gene 3, encodes a putative mitochondrial protein of 760 amino acid residues that is closely related to FtsH, Tma (protein from Lactococcus lactis) and Yme1p with 58, 55 and 46% identity respectively. The sequence has been deposited in the EMBL data library under Accession Number X76643.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 92
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 1321-1327 
    ISSN: 0749-503X
    Schlagwort(e): Firefly luciferase ; yeast expression ; gene reporter ; Saccharomyces cerevisiae ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The LUC gene coding for Photinus pyralis firefly luciferase was cloned in different yeast episomal plasmids in order to assess its possibilities as an in vivo reporter gene. Activity of the enzyme in transformed cells in vivo was measured by following light emission and assay conditions optimized in intact cells, with regard to oxygen concentration, temperature, cell concentration in assay mixtures and external ATP concentration. Among the factors tested, light emission was drastically influenced by the external pH in the assay (which resulted in a ten-fold amplification signal) and by substrate permeability. The growth phase of the cells was also important for the level of activity detected. Cloning of firefly luciferase gene under the control of different yeast-regulated promoters (ADH1, GAL1-10) enabled us to measure their strength which correlated well with previously described data. We conclude that firefly luciferase is an adequate gene reporter for the in vivo sensitive determination of gene expression and promoter strength in yeast.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 93
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 1395-1402 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 94
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 1403-1413 
    ISSN: 0749-503X
    Schlagwort(e): Chromosome XI of Saccharomyces cerevisiae ; transcript map ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A detailed and systematic transcript map is a first and necessary step to characterize new genes revealed by systematic sequencing. Chromosome XI of Saccharomyces cerevisiae contains 331 open reading frames (ORFs) of which 44% are of unknown function (Dujon et al., 1994). As a first study towards complete transcript analysis of chromosome XI, we have extracted RNA from three isogenic strains (a, α and 2 n) grown in three standard laboratory media, and have analysed them using contiguous probes covering two regions of 17 and 19 kilobases, respectively. All 20 predicted ORFs in the sequences correspond to expressed genes, six of which have no predicted function. Four short ORFs which were suspected as not being real genes on the basis of their sequence are not expressed in our growth conditions. An additional transcript which does not correspond to a large ORF was found. Steady-state RNA level of most ORFs is 10 to 100 times than that of the actin gene, only three are transcribed in comparable amounts. Three ORFs show variable levels of transcripts in the different growth conditions, all patterns being different from one another. Extrapolation of these results to systematic transcript analysis of chromosome XI and other yeast chromosomes is presented.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 95
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994), S. 1459-1466 
    ISSN: 0749-503X
    Schlagwort(e): Pichia pinus ; glucose catabolite repression ; glucose transport ; isolation of mutants ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A new method for the isolation of glucose repression-insensitive mutants in the methylotrophic yeast Pichia pinus was developed. The method is based on screening of small suspension samples derived from 2-deoxyglucose-resistant colonies for alcohol oxidase activity. Alcohol oxidase activity was evaluated by determination of formaldehyde excreted by cells. Mutants with glucose non-repressible alcohol oxidase and catalase synthesis were obtained. All mutants grew poorly on D-xylose compared to the wild type, whereas growth on L-arabinose was similar to the wild type. Changes in the glucose transport system were suggested to be responsible for altered growth characteristics and defective glucose repression.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 96
    ISSN: 0749-503X
    Schlagwort(e): Candida tropicalis ; peroxisomes ; nonspecific lipid-transfer protein ; sterol carrier protein-2 ; stress protein ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: A 14-kDa peroxisomal-matrix protein, named PXP-18, of the yeast Candida tropicalis is a structural and functional homologue of the mammalian nonspecific lipid-transfer protein (identical to sterol carrier protein-2). PXP-18 protected acyl-coenzyme A oxidase (ACO), the rate limiting enzyme of the peroxisomal β-oxidation of fatty acids, from thermal inactivation at 48°C or 70°C. This effect was dose-dependent and not replaceable either by chicken egg white lysozyme, which is similar to PXP-18 (insofar as it is basic, small, and monomeric), or by bovine serum albumin, a carrier of lipids in the blood. ACO was irreversibly denatured by heat treatment at 70°C for 15 min. However, when ACO and PXP-18 were similarly heat-treated, they formed a large complex at a molar ratio of PXP-18 to ACO subunit that was about one, independent of their initial ratio. This near-stoichiometric complex had ACO activity after a 500-fold dilution and was accompanied by ACO that was free of PXP-18 and indistinguishable from native ACO in size and activity. PXP-18 also protected urate oxidase, another peroxisomal enzyme, from inactivation at 66°C for 15 min and facilitated the renaturation of ACO denatured by 2 M urea. These results indicated that PXP-18 is active in modulating the structure of peroxisomal enzymes in vitro. It is possible that PXP-18 functions as a stress protein or as a part of the system that keeps peroxisomal proteins intact.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 97
    ISSN: 0749-503X
    Schlagwort(e): Yeast ; genome ; ribosomal protein S13 ; SUP46 ; URP1 ; rat ribosomal protein L21 ; AAA-family proteins ; MADS-domain ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The nucleotide sequence of a 12·5 kb fragment localized to the right arm of chromosome II of Saccharomyces cerevisiae has been determined. The sequence contains eight putative genes. Two of them are contiguous and represent two ribosomal protein genes: SUP46 and URP1. SUP46 is implicated in translation fidelity and encodes the ribosomal protein S13. URP1 is homologous to the rat ribosomal protein gene L21. The open reading frame (ORF) YBR1245 is similar in its N-terminal part to transcription factors like SRF and MCM1. The ORF YBR1308 shows homology with proteins of the AAA-family (ATPases Associated with diverse cellular Activities). Two genes are predicted to encode putative membrane proteins. The sequence has been deposited in the EMBL data library under Accession Number U02073.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 98
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 10 (1994) 
    ISSN: 0749-503X
    Schlagwort(e): Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 99
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; chromosome IV ; POL3 (CDC2) ; KIN28 ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The nucleotide sequence of a 5 kb EcoRI-NcoI fragment of chromosome IV, contiguous to gene POL3 (CDC2), has been determined. It contains three open reading frames: QRI1, QRI2 and QRI7. Two of them are essential genes. QRI7 is homologous to the Escherichia coli orfx gene. Accession number to EMBL/Genbank Data Library is X79380.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 100
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; chromosome X ; hexose transporter ; α-glucosidase ; left telomere ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have sequenced on both strands a 40,257 bp fragment located near the left telomere of chromosome X of Saccharomyces cerevisiae.The sequenced segment contains 21 open reading frames (ORFs) at least 100 amino acids long. Five of the ORFs correspond to known amino acid sequences: two hypothetical proteins in the subtelomeric Y′ repeat region of 65·4 and 12·8 KDa, the cytochrome B pre-mRNA processing CBP1 protein, the mitochondrial nuclease NUC1 and the CRT1 protein. Of the 16 remaining ORFs, eight show highest homologies with the S. cerevisiae hexose transporters family (two ORFs), the yeast α-glucosidase (two ORFs), the yeast PEP1 precursor, the Escherichia coli galactoside O-acetyltransferase, the S. cerevisiae 137·7 KDa protein located in the Y′ region and a protein of unknown function of Schizosaccharomyces pombe. Finally, eight of the ORFs exhibit no significant similarity with any amino acid sequences described in data banks.DNA sequence comparison has revealed the presence of different repeated elements characteristic of yeast chromosome ends.Disruption studies have been performed on two ORFs encoding putative proteins of unknown function.The sequence has been entered in the EMBL Data Library under Accession Number Z34098.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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