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  • 2020-2023
  • 1980-1984  (21)
  • 1955-1959  (8)
  • 1925-1929
  • 1890-1899
  • gene expression
  • protoplasts
  • 1
    ISSN: 1573-4927
    Schlagwort(e): amphibian development ; allelic isozyme variants ; gene expression ; maternal effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The polymorphism of three enzymes [lactate dehydrogenase B (LDH-B), glucose-6-phosphate dehydrogenase, (G6PDH), and peptidase-1 (PEP-1)] in Pleurodeles waltl has allowed the expression of the corresponding loci to be followed during the development of spawnings arising from various crosses. A maternal effect lasting up to the late tail-bud stage (approx. stage 28) was shown for PEP-1. A similar situation was observed for LDH-B and G6PDH. The embryonic alleles present retarded expression: from about stage 28 for PEP-1 and G6PDH and from about stages 22 to 24 (the young tail-bud stage) for LDH-B.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 22 (1984), S. 901-911 
    ISSN: 1573-4927
    Schlagwort(e): cat hemoglobins ; cell-free translation ; polymorphism ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The molecular basis for the genetic control of variable proportions of the two hemoglobins in domestic cat blood was investigated. Both major hemoglobins of cat blood, HbA (α2β 2 A ) and HbB (α2β 2 B ), were synthesized in an mRNA-dependent rabbit reticulocyte system using poly(A)-RNA from cat reticulocyte polysomes as the source of the message. The relative amounts of HbA and HbB synthesized in the system were a function of the HbA/HbB phenotype of the cat from which the reticulocytes and poly(A)-RNA were obtained. Higher ratios of HbA/HbB synthesis were found when the source of poly(A)-RNA was the polysomes from a 90/10 (HbA/HbB) phenotype than when it was from a 50/50 (HbA/HbB) phenotype. These results indicate that the variable proportions of HbA and HbB found in the blood of different members of the cat population result from the genetic control of the relative amounts of functional βA and βB mRNA.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 116-117 (1984), S. 319-320 
    ISSN: 1573-5117
    Schlagwort(e): seaweed ; enzyme ; protoplasts ; decomposition ; preparation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 24 (1984), S. 271-285 
    ISSN: 0730-2312
    Schlagwort(e): photosystem development ; chloroplast structure ; chloroplast function ; photosynthetic unit ; gene expression ; regulation ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: The light environment during plant growth determines the structural and functional properties of higher plant chloroplasts, thus revealing a dynamically regulated developmental system. Pisum sativum plants growing under intermittent illumination showed chloroplasts with fully functional photosystem (PS) II and PSI reaction centers that lacked the peripheral chlorophyll (Chi) a/b and Chl a light-harvesting complexes (LHC), respectively. The results suggest a light flux differential threshold regulation in the biosynthesis of the photosystem core and peripheral antenna complexes. Sun-adapted species and plants growing under far-red-depleted illumination showed grana stacks composed of few (3-5) thylakoids connected with long intergrana (stroma) thylakoids. They had a PSII/PSI reaction center ratio in the range 1.3-1.9. Shade-adapted species and plants growing under far-red-enrichcd illumination showed large grana stacks composed of several thylakoids, often extending across the entire chloroplast body, and short intergrana stroma thylakoids. They had a higher PSII/PSI reaction center ratio, in the range of 2.2-4.0. Thus, the relative extent of grana and stroma thylakoid formation corresponds with the relative amounts of PSII and PSI in the chloroplast, respectively. The structural and functional adaptation of the photosynthetic membrane system in response to the quality of illumination involves mainly a control on the rate of PSII and PSI complex biosynthesis.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 26 (1984), S. 117-125 
    ISSN: 0730-2312
    Schlagwort(e): gene expression ; amelogenins ; cDNA ; type II cells ; pulmonary surfactant ; ameloblasts ; epithelial differentiation ; regional mesenchymal specificity ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: One of the major problems in developmental biology concerns how differential gene activity is regionally controlled. One approach to this problem is the use of mesenchyme specification of epithelial-specific gene expression, such as, during tooth morphogenesis or lung morphogenesis. In the example of tooth morphogenesis, dental papilla ectomcsenchyme induces de novo gene expression as assayed by detection of amelogenin transcripts, or immunodetection of amelogenin poly-peptidcs within ameloblast cells. This process does not require serum supplementation or exogenous factors during epithelial-mesenchymal interactions in vitro. In contrast, lung morphogenesis requires hormones to mediate mesenchyme-derived influences upon type II epithelial cell differentiation and the production of pulmonary surfactant (eg, neutral and phospholipids, surfactant proteins). Glucocorticoids are required to stimulate the release of fetal pneumonocyte factor (FPF) from fibroblasts which, in turn, enhance the production of pulmonary surfactant. Thy-roxin appears to regulate the relative responsiveness of progenitor type II cells to steroid-stimulated release of FPF. This review will highlight key concepts associated with these developing organ systems and emphasize the problem of regional controls which regulate epithelial cell-specific gene activity.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 5 (1984), S. 27-42 
    ISSN: 0192-253X
    Schlagwort(e): gonad differentiation ; gene expression ; two-dimensional micro gel electrophoresis ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Gonadal protein patterns were studied during development in the rat by two-dimensional micro-gel electrophoresis. Specific proteins were detected in both the male and the female sex at the morphologically indifferent state (two female- and one male-specific) and during differentiation. At the onset of gonadal differentiation (day 14) two additional sex-specific proteins were discovered in the male and two in the female. These proteins remained expressed during further development. One testicular protein was restricted to the cytosol of the tunica albuginea. The other one was absent from the tunica. In the female gonad, the two proteins were membrane-specific, one present in germ cells, the other in somatic cells. In the testis, one additional protein was discovered at postnatal day 1. Thus according to biochemical criteria there is no indifferent state of gonadal development. The testis and ovary express sex-specific genes both before and after the onset of gonadal differentiation.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 21 (1983), S. 819-841 
    ISSN: 1573-4927
    Schlagwort(e): evolution ; polyploidy ; ribosomal RNA ; protein synthesis ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Hidden breaks occur in the ribosomal RNA of tetraploid Cyprinid fish such that the large ribosomal RNA (28 S) yields upon denaturation two RNA fragments of 8.7×105 and 5.0×105 daltons, whereas the small rRNA (18 S) yields fragments of 3.2×105 to 5.0×104 daltons. In tetraploid Cyprinids hidden breaks occur only in the rRNA of somatic tissue and not in oocytes and sperm cells. Hidden breaks can be detected only slightly in diploid Cyprinid species. Ribosomes purified from somatic tissue of tetraploid Cyprinids show a reduced efficiency in protein synthesis in vitro. The ribosomal proteins from diploid and tetraploid Cyprinid fish show considerable electrophoretic differences. This is discussed in light of a possible functional role of hidden breaks in rRNA in the process of diploidization of gene expression in tetraploid Cyprinid species.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1573-5028
    Schlagwort(e): alfalfa mosaic virus ; protoplasts ; viral antigen detection flow cytometry ; fluorescence-activated cell sorter
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Immunofluorescence flow cytometry was used to study the distribution of viral antigen in protoplast populations. Protoplasts were isolated from healthy and alfalfa mosaic virus (AMV) infected tobacco leaves (designated in vivo infected). Furthermore isolated tobacco and cowpea protoplasts were infected in vitro with AMV. The FITC-conjugated antibodies could penetrate formaldehyde fixed protoplasts. The flow cytometric measurements were rapid and reproducible. Comparable immunofluorescence patterns were found for all infected samples (per sample 104 protoplasts were measured). Infectious virus could only be detected in in vivo infected tobacco protoplasts and in in vitro infected cowpea protoplasts.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1573-5028
    Schlagwort(e): alfalfa mosaic virus ; mutant ; protoplasts ; supplementation ; repression ; host response ; hypersensitive reaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A mutant of alfalfa mosaic virus (AMV), which in contrast to wild type (wt) can invade cowpea plants systemically, is replicated more efficiently in cowpea protoplasts than the wt. Mutant preparations isolated from infected cowpea protoplasts contained a higher amount of middle component (M, containing RNA 2) than wt preparations. Both in cowpea plants and in cowpea protoplasts a wt phenotype is obtained upon addition of wt M to this mutant, suggesting a correlation between the type of plant reaction evoked by the virus infection and the regulation of viral RNA synthesis.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1573-5028
    Schlagwort(e): spinach chloroplast DNA ; gene expression ; initiation of transcription
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Thein vitro DNA- or RNA-directed synthesis of the large subunit (LS) of spinach chloroplast ribulose-1,5-biphosphate carboxylase (RuP2C) has been examined in a highly definedE. coli transcription-translation system. Spinach chloroplast DNA, RNA and recombinant plasmids containing the spinach chloroplast LS gene (rbcL) have been used as templates in thein vitro system and a quantitative assay has been developed to measure LS formation. Thein vitro formed product contains formylmethionine at the N-terminal position and sediments primarily as a monomer. There is no detectable enzymatic activity associated with thein vitro product. To determine where theE. coli RNA polymerase used in these systems initiates, we have examined the transcripts produced by this enzymein vitro. Measurements of run-off transcripts indicate thatE. coli RNA polymerase initiates at the same position on the gene as is seenin vivo. In addition, the complete nucleotide sequence of therbcL gene including previously unsequenced 3′ and 5′ flanking regions has been determined. The sequence agrees, except at two nucleotide positions, with previously published sequencing data for this gene (Zurawski, G, Perrot, B, Bottomley, W, Whitfeld, PR, 1981. Nucleic Acids Res. 9:3251–3270).
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 2 (1983), S. 217-226 
    ISSN: 1573-5044
    Schlagwort(e): protoplasts ; agarose ; Nicotiana tabacum ; Nicotiana plumbaginifolia ; Daucus carota ; Hyoscyamus muticus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Media solidified with agarose resulted in higher plating efficiency of protoplasts than commonly used agar media. Improved culture efficiency was observed with mesophyll protoplasts of Nicotiana tabacum and N. plumbaginifolia and with protoplasts isolated from cell lines of Daucus carota, Hyoscyamus muticus and two lines of N. tabacum. The improvement with agarose was consistent over a wide cell density range and also for different media. The positive effect was not due to the lower temperature at which the protoplasts could be plated. Culture experiments with mixtures of different agar types generally gave intermediate division frequencies. There was no obvious effect on plating efficiency in experiments where diffusion was permitted between agar and other agar types.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Basic research in cardiology 78 (1983), S. 203-209 
    ISSN: 1435-1803
    Schlagwort(e): mRNA ; rat ; heart muscle ; biopsies ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Durch Kombination konventioneller mRNS-Isolierungsverfahren mit neueren mRNS-Hybridisierungstechniken wurde eine Methode entwickelt, die die Quantifizierung myokardialer, Poly(A)-enthaltender mRNS in Myokardbiopsien ermöglicht. Dadurch wird es möglich, Veränderungen der myokardialen Genexpression direkt in Myokardbiopsien zu untersuchen. Die beschriebene Methode kann daher besonders nutzvoll sein, wenn Veränderungen der myokardialen Genexpression bei menschlichen oder tierischen Herzmuskelerkrankungen erwartet werden und wenn andererseits aber nur Herzmuskelbiopsien für die Untersuchungen zur Verfügung stehen.
    Notizen: Summary Using a combination of conventional mRNA-extraction methods and newer hybridization techniques, a method was developed which allows the quantitation of cardiac Poly(A)-containing mRNA in cardiac biopsies. This provides a new tool to directly assess changes in cardiac gene expression in cardiac biopsies. It is proposed that the method described may be valuable in investigations dealing with various human or animal heart diseases where changes in cardiac gene expression are expected and where only biopsy material is available.
    Materialart: Digitale Medien
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  • 13
    ISSN: 1573-4927
    Schlagwort(e): esterase ; duplication ; gene expression ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract An esterase duplication is described in the sibling species pair Drosophila mojavensis and Drosophila arizonensis. We present evidence for two separate structural loci mapping at a distance of less than 0.16 recombination units from each other. Alleles at the two loci have the same substrate specificities and form small amounts of interlocus heterodimers. One locus (Est-5) is functioning throughout the insect's life cycle and appears at high concentrations in the hemolymph and the fat body. Its duplicate (Est-4) functions only during the late larval stage and is concentrated mainly in the carcass. No null alleles at either locus were observed in population surveys. An examination of 12 other species from the repleta group, to which D. mojavensis and D. arizonesis belong, suggests that Est-5 is universally present, but the activity levels of Est-4 vary among species and may be totally absent in some species. Variation in the level of Est-4 activity does not closely follow the phylogenetic relationship.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 1 (1982), S. 89-102 
    ISSN: 1573-5028
    Schlagwort(e): sorghum ; mitochondria ; cytoplasmic male sterility ; plasmids ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Variation in sorghum mitochondrial translation products has enabled fertile (Kafir) cytoplasm to be distinguished from Milo cytoplasmic male sterile cytoplasm and from three alternative sources of cytoplasmic male sterile cytoplasm. Mitochondria from Milo cytoplasm synthesised a 65 000 mol. wt. polypeptide which was not synthesised by those from Kafir cytoplasm. In the cytoplasmic male sterile combination of Kafir nucleus in Milo cytoplasm synthesis of this polypeptide was dramatically increased. Mitochondria from two cytoplasmic male sterile lines (Kafir nucleus in IS1112 cytoplasm and Yellow Feterita nucleus in M35-1 cytoplasm) did not synthesise the 65 000 mol. wt. polypeptide but synthesised additional high molecular weight polypeptides (from 54 000 to 82 000 mol. wt.), the major one being 82 000. Mitochondria from cytoplasm IS1112 were also distinguished by synthesis of an additional 12 000 mol. wt. polypeptide. Mitochondria from the cytoplasmic male sterile line Martin nucleus in 9E cytoplasm synthesised an additional 42 000 mol. wt. polypeptide but did not synthesise a 38 000 mol. wt. polypeptide detected in all other cytoplasms. Immunoprecipitation of mitochondrial translation products with antiserum raised against subunit I of yeast cytochrome oxidase tentatively identified the 38 000 mol. wt. polypeptide as subunit I of sorghum cytochrome oxidase. The 42 000 mol. wt. polypeptide was also immuno-precipitated by this antiserum and thus is probably an altered form of cytochrome oxidase subunit I. Analysis of native mitochondrial DNA by agarose gel electrophoresis revealed the presence of two ‘plasmid-like’ DNA species of molecular weight 5.3 and 5.7 kb in the cytoplasmic male sterile lines Kafir nucleus in cytoplasm IS1112 and Yellow Feterita nucleus in M35-1 cytoplasm. Thus there is a positive correlation between the synthesis of the 82 000 mol. wt. polypeptide and the presence of the additional DNA species.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    The journal of membrane biology 67 (1982), S. 13-26 
    ISSN: 1432-1424
    Schlagwort(e): cell rotation ; polarization ; protoplasts ; dielectric breakdown
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary Protoplasts ofAvena sativa rotate in an alternating electric field provided that at least two cells are located close to each other. An optimum frequency range (20 to 30 kHz) exists where rotation of all cells exposed to the field is observed. Below and above this frequency range, rotation of some cells is only occasionally observed. The angular velocity of rotation depends on the square of the electric field strength. At field strengths above the value leading to electrical breakdown of the cell membrane, rotation is no longer observed due to deterioration of the cells. The absolute value of the angular velocity of rotation at a given field strength depends on the arrangement of the cells in the electric field. A maximum value is obtained if the angle between the field direction and the line connecting the two cells is 45o. With increasing distance between the two cells the rotation speed decreases. Furthermore, if two cells of different radii are positioned close to each other the cell with the smaller radius will rotate with a higher speed than the larger one. Rotation of cells in an alternating electric field is described theoretically by interaction between induced dipoles is adjacent cells. The optimum frequency range for rotation is related to the relaxation of the polarization process in the cell. The quadratic dependence of the angular velocity of rotation on the field strength results from the fact that the torque is the product of the external field and the induced dipole moment which is itself proportional to the external field. The theoretical and experimental results may be relevant for cyclosis (rotational streaming of cytoplasm) in living cells.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 3 (1982), S. 7-23 
    ISSN: 0192-253X
    Schlagwort(e): gene expression ; superoxide dismutase ; Zea mays ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Immunoassays for the cytosolic and mitochondrial superoxide dismutases (SOD) of maize were developed and used to study the expression of these proteins in the maize seedling. The genetically distinct proteins, SOD-3 and SOD-4, are preferentially expressed in the scutellum, comprising approximately 1% of the total water-soluble protein of that tissue. SOD-2, SOD-3, and SOD-4 are synthesized in the scutellum during early sporophytic development, probably on cytosolic ribosomes. Two-dimensional gel electrophoresis of crude scutellar extracts indicates that significant changes occur in the protein composition of the maize scutellum following seed imbibition. Using the immunoassays, a maize line exhibiting a significant reduction in cyanide-sensitive SOD protein was identified.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 3 (1982), S. 275-282 
    ISSN: 0192-253X
    Schlagwort(e): Drosophila ; sex chromosomes ; gene dosage ; gene expression ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: In Drosophila, the ratio of the number of X chromosomes to sets of other chromosomes initiates a series of events which result in sexual differentiation. In addition, this ratio establishes dosage compensation, a mechanism which equalizes the products of X-linked genes in males and females. The present review discusses possible genetic entities responsible for the interpretation of chromosomal sex and subsequent sex-mediated regulation during development.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 1 (1981), S. 149-164 
    ISSN: 1573-5044
    Schlagwort(e): Saccharum ; cell culture ; protoplasts ; embryogenesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Experiments are described which improve the protocols for initiating in vitro cultures of sugarcane and allowing efficient regeneration of plants even after 30 months of callus proliferation. Procedures adopted included use of leaf base explants, CS medium with 3 mg/l 2, 4-D and 0.25 mg/l kinetin for callus initiation and growth, MS medium with 0.5 mg/l IAA and 1 mg/l BAP for shoots, MS medium with 5 mg/l NAA and 7% (wt/vol) sucrose for rooting of shoots. Casein hydrolysate (N-Z amine) significantly shortened the lag period in the growth of sugarcane suspension cultures, but did not increase the rate of growth following the lag phase. Protoplasts isolated from two types of cultures could be grown to re-establish cell cultures but no plants have yet been regenerated derived from isolated protoplasts.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 1 (1981), S. 201-209 
    ISSN: 1573-5044
    Schlagwort(e): protoplasts ; suspension cells ; callus formation ; winged bean ; Psophocarpus tetragonolobus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A system was developed for protoplast isolation and culture from suspension cultured cells of winged bean,Psophocarpus tetragonolobus. Cells from a three-day-old suspension were incubated in an enzyme mixture containing 6% cullulysin, 1% Macerase, 1% desalted Rhozyme, 0.4M sorbitol, and 0.1M CaCl2 at pH 5.5. Average yields of protoplasts were 6.5 × 106 per gram fresh weight of cells. Protoplasts were cultured in modified B5 medium containing 68.4 g/l glucose, 250 mg/l xylose, 0.1 mg/l 2,4-D, 0.5 mg/l BAP, 250 mg/l N-Z amine type AS, and 20 ml/l coconut water. After 24 h of culture, the protoplasts had synthesized a new wall, and in three days had begun division. The optimum plating density was 1–2 × 103 protoplasts/ml. The division frequency ranged between 40%–60% for most experiments with a high of 72% in one experiment. After three weeks, cell colonies could be transferred to solid MS medium containing N-Z amine and coconut water where callus developed. This protoplast system is technically comparable to soybean for experiments concerned with genetic manipulation involving legumes.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 18 (1980), S. 353-364 
    ISSN: 1573-4927
    Schlagwort(e): carboxylesterase ; electrophoretic variants ; fish development ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Two esterases splitting α-naphthylacetate have been found in the tissues of adult loaches and in embryos. These were identified as arylesterase (E-1) (arylester hydrolase, E.C. 3.1.1.2) and carboxylesterase (E-2) (carboxylic ester hydrolase, E.C. 3.1.1.1.). In unfertilized loach eggs E-1 and E-2 synthesized during oogenesis were found. Active E-2 synthesized under the control of E-2 genes of the embryo appeared in embryos from the stage of 40–50 h of development. Maternal E-2 molecules synthesized in oogenesis or on the stored templates in embryogenesis persisted in larvae up to days 5–6 of development. Two genes controlling the synthesis of two forms of E-2 differing in electric mobility were found in the loach population from the delta of the Danube. The genes for fast and slow E-2 were shown to segregate in meiosis and to be allelic.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Bulletin of experimental biology and medicine 89 (1980), S. 666-668 
    ISSN: 1573-8221
    Schlagwort(e): protoplasts ; fusion of protoplasts ; regeneration ; “primary prototrophs.”
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
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  • 22
    ISSN: 1573-5060
    Schlagwort(e): protoplasts ; protoclonal variation ; somatic hybridization ; top-fruit trees ; woody ornamentals
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Until recently, temperate fruit trees and woody ornamentals have been regarded as recalcitrant to biotechnological breeding approaches based on protoplasts. This however should no longer be the case, as procedures are now available, not only for the regeneration of complete plants from protoplasts of various tissues of such species, but also for the exploitation of protoplast technology for their genetic manipulation. This paper will examine the recent advances and state of the art in this domain, with particular attention to the use of protoplast technology as a novel tool in the breeding of rosaceous top-fruit tree species and woody ornamentals. Problems and their solutions within the context of regenerating plants from isolated protoplasts of stone (Prunus spp.), pome (Pyrus spp., Malus spp.) and small (Rubus spp.) fruits, and of several shrubby ornamental genotypes (Lonicera spp., Weigela spp., Forsythia spp., Cotoneaster spp.) will be addressed. Interspecific (Prunus spinosa + Prunus cerasifera) and intergeneric (Forsythia spp. + Syringa spp.) somatic hybridization within this group of species, as well as the use of protoplasts for host/pathogen interaction studies (Pyrus/Erwinia amylovora) will also be discussed.
    Materialart: Digitale Medien
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  • 23
    ISSN: 1573-5060
    Schlagwort(e): microprotoplast fusion ; partial genome transfer ; monosomic additions ; kanamycin resistance ; β-glucuronidase ; gene expression ; potato
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Various aspects of a microprotoplast fusion technique and the strategies followed for intergeneric partial genome transfer (one or a few chromosomes) and alien genes from sexually-incongruent donor species to recipient species are described. The essential requirements of the microprotoplast fusion technique are the induction of micronuclei at high frequencies, as well as the isolation and enrichment of sub-diploid microprotoplasts in donor species, efficient fusion of the donor microprotoplasts with normal recipient protoplasts and stable regeneration of plants from fusion products. The results on the production of microprotoplast hybrid plants between the transformed donor lines of Solanum tuberosum and Nicotiana Plumbaginifolia carrying various genetic markers, and a recipient line of Lycopersicon peruvianum or Nicotiana tabacum, and on the transfer and expression of alien genes (kanamycin resistance, β-glucuronidase) are presented. The data obtained on microprotoplast hybrid plants between S. tuberosum and L. peruvianum showed that many of the hybrids contained one potato chromosome carrying nptII and GUS, and 24 or 48 L. peruvianum chromosomes (monosomic additions), and that they were male-and female-fertile. Various applications of chromosome transfer by this technique, especially for economically-important traits (e.g. disease or stress resistance) from sexually-incompatible wild species, for construction of chromosome-specific DNA libraries through microdissection and microcloning of chromosomes, or by flow-sorting of chromosomes for genome analysis, are discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 24
    ISSN: 1573-5060
    Schlagwort(e): Agrobacterium ; Brassica napus ; CaMV 35S promoter ; mas promoter ; gene expression ; risk assessment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Gene fusions between the β-glucuronidase (GUS) reporter gene and the promoters of the cauliflower mosaic virus 35S RNA transcript (CaMV 35S) and the mannopine synthase (mas) genes were introduced into rapeseed varieties via Agrobacterium-mediated transformation. Fluorometric assay of β-glucuronidase activity indicated different expression patterns for the two promoters. In seedlings, the CaMV 35S promoter had maximum activity in the primary roots, while the mas promoter was most active in the cotyledons. Etiolated seedlings cultured in the dark showed reduced activity of the mas promoter. Before vernalization at the rosette stage, both promoters were more active in older plant parts than in younger ones. At this stage the highest activity was recorded in cotyledons. After the plants had bolted reduced promoter function was detected in the upper parts of the transformed plants. Both promoters were found to be functional in the majority of the studied organs of transgenic rapeseed plants, but the promoter activity varied considerably between the organs at different developmental stages. The ability of pollen to transfer the introduced genes to other varieties and related species (e.g. Brassica napus and Diplotaxus muralis) by cross-pollination was studied in greenhouse experiments, and field trials were carried out to estimate the distance for biologically-relevant gene dispersal. In artificial crossing, the introduced marker gene was transferable into other varieties of Brassica napus. In field trials, at a distance of 1 metre from the source of transgenic plants, the frequency of an outcrossing event was relatively high (10-3). Resistant individuals were found at 16 and 32 metres from the transgenic pollen donors, but the frequency of an outcrossing event dropped to 10-5.
    Materialart: Digitale Medien
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  • 25
    ISSN: 1573-5060
    Schlagwort(e): barley ; electroporation ; PEG-mediated DNA uptake ; promoter analysis ; protoplasts ; transient expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary In some cereal species that are still recalcitrant to stable transformation and regeneration, transient expression in isolated protoplasts is a useful tool for the study of gene expression and regulation. We have successfully applied these techniques to barley protoplasts derived from developing endosperm, aleurone, leaves and roots in order to characterize functionally cis-acting motives in two gene promoters, corresponding to trypsin inhibitor BTI-CMe and to sucrose synthase Ss1. Gene specificity is maintained in transient expression assays with protoplasts isolated from these different barley tissues and the pattern of expression parallels the mRNA levels observed for the corresponding genes in the same tissues.
    Materialart: Digitale Medien
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  • 26
    ISSN: 1573-5060
    Schlagwort(e): Oryza sativa L. cv. Taipei 309 ; rice ; protoplasts ; direct DNA uptake ; kanamycin-resistant transgenic plants ; field trial ; glasshouse trial ; neomycin phosphotransferase II (npt II) gene ; gene expression and inheritance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The phenotypes of seed progeny (R2 generation) of Oryza sativa L. cv. Taipei 309, which carried the neomycin phosphotransferase II (npt II) gene, were compared with those of non-transformed, protoplast-derived plants of the same generation and non-transformed, seed-derived plants under field and glasshouse conditions. Under both conditions the transgenic plants were generally smaller, took longer to flower and had reduced fertility. Significant differences were observed between individuals within the group of transgenic plants. The npt II gene was present in most of the transgenic plants, but NPT II activity was only detected in a minority of individuals.
    Materialart: Digitale Medien
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  • 27
    ISSN: 1573-5060
    Schlagwort(e): bleomycin ; direct gene transfer ; expression ; irradiation ; petunia ; protoplasts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The production of transgenic plants by means of direct gene transfer to protoplasts is now a widely-used technique. The biological mechanisms underlying the transformation are still poorly understood, but many investigations have attempted to shed light on some components of this process. Varying the experimental conditions has in some cases led to better transformation rates, but further improvements of the protocols are possible. Such improvements will require a better understanding of how the alien DNA enters the cells, becomes integrated into the chromosomes and is treated as a part of the plant genome. Irradiation with sublethal doses of X-rays or UV-light has been shown to increase the transformation frequency, while certain drugs have been shown to act in a similar manner. The effects of these and other factors are discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 28
    ISSN: 1573-5060
    Schlagwort(e): carotenoids ; ethylene ; gene expression ; Lycopersicon esculentum Mill. ; polygalacturonase ; pectinesterase ; phytoene synthase ; ACC oxidase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The common cultivated tomato (Lycopersicon esculentum Mill.) provides a major focus for improvement of crop quality through genetic engineering. Identification of ripening-related cDNAs has enabled the modification of specific aspects of ripening by manipulating gene expression in transgenic plants. By utilizing ‘antisense RNA’ to modify expression of ripening genes, we have inhibited the production of the cell wall-metabolising enzymes polygalacturonase and pectinesterase and created transgenic plants that contain, effectively, single, targeted mutations affecting these genes. Furthermore, this approach has been used with previously unidentified cDNA clones to enable both functional identification and manipulation of genes involved in ethylene production (ACC oxidase) and carotenoid biosynthesis (phytoene synthase). The use of antisense RNA targeted to specific genes to alter ripening phenotypes and improve commercial utility of fruit by affecting shelf-life, processing characteristics and nutritional content is discussed. We have used the extreme ripening-impaired mutant, ripening inhibitor (rin) to identify additional genes implicated in the ripening process. This approach has resulted in the cloning of several novel ripening-related mRNAs which are now being studied by antisense experiments. This may enable identification and manipulation of additional genes involved in processes such as softening, flavour and aroma generation and susceptibility to pathogens.
    Materialart: Digitale Medien
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  • 29
    ISSN: 1573-5060
    Schlagwort(e): Vicia narbonensis ; gene transfer ; gene expression ; seeds ; 2S albumin ; methionine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Epicotyl explants were co-cultivated with Agrobacterium tumefaciens EHA101 to transfer a chimeric 2S albumin gene construct carried in the binary Ti plasmid vectors pGSGLUC1 or pGA472 into the grain legume Vicia narbonensis. This gene encoding the sulphur-rich Brazil nut albumin was under the control of either the CaMV 35S promoter which permits gene expression in all organs, or the Vicia faba legumin B4 promoter which elicits seed-specific gene expression. After callus formation and selection for kanamycin resistance, somatic embryos were induced which, in the case of transformation with the vector pGSGLUC1, were screened for GUS activity. Embryos that produced GUS were in addition analysed for 2S albumin formation. Selected transgenic embryos were cloned by multiple shoot regeneration. Rooted and fertile plants were obtained by grafting transgenic shoots on the appropriate seedlings. R1 and R2 generations were raised and analysed for GUS as well as 2S albumin gene expression. Expression of the 35S promoter/2S albumin gene fusion took place in all organs of the transgenic plants including the cotyledons of seeds, whereas seed-specific gene expression was found in transformants with the legumin promoter/2S albumin gene fusion. The 2S albumin accumulated in the 2S protein fraction of transgenic seeds and its primary translation product was processed into the 9 and 3 kDa polypeptide chains. The foreign protein was localised in the protein bodies of the grain legume. Analysis of the R2 plants indicated Mendelian inheritance of the 2S albumin gene. In homozygous V. narbonensis plants the amounts of 2S albumin were twice that present in the corresponding heterozygous plants. Whereas only low level formation of the foreign protein was achieved if the gene was under the control of the 35S promoter, approximately 3.0% of the soluble seed protein was 2S albumin if seed-specific gene expression was directed by the legumin B4 promoter. Some of these transformants exhibited a three-fold increase in the methionine content of the salt-soluble protein fraction extracted from seeds.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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