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  • Physics  (5)
  • Choline acetyltransferase  (4)
  • Lepidoptera  (4)
  • Gene expression  (3)
  • 1
    ISSN: 1432-2048
    Schlagwort(e): Atriplex ; Gene expression ; NaCl regulation ; Halophyte ; Plasma-membrane H+-ATPase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An Atriplex nummularia L. cDNA probe encoding the partial sequence of an isoform of the plasma-membrane H+ -ATPase was isolated, and used to characterize the NaCl regulation of mRNA accumulation in cultured cells of this halophyte. The peptide (447 amino acids) translated from the open reading frame has the highest sequence homology to the Nicotiana plumbaginifolia plasma-membrane H+-ATPase isoform pma4 (greater than 80% identity) and detected a transcript of approximately 3.7 kb on Northern blots of both total and poly(A)+ RNA. The mRNA levels were comparable in unadapted cells, adapted cells (cells adapted to and growing in 342 mM NaCl) and deadapted cells (cells previously adapted to 342 mM NaCl that are now growing without salt). Increased mRNA abundance was detected in deadapted cells within 24 h after exposure to NaCl but not in unadapted cells with similar salt treatments. The NaCl up-regulation of message abundance in deadapted cells was subject to developmental control. Analogous to those reported for glycophytes, the plasma-membrane H+-ATPase are encoded by a multigene family in the halophyte.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 202 (1993), S. 159-169 
    ISSN: 1432-041X
    Schlagwort(e): Drosophila ; Choline acetyltransferase ; cis-Regulatory element ; lacZ reporter gene ; Colinergic neuron
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Choline acetyltransferase (ChAT, EC 2.3.1.6) catalyzes the production of the neurotransmitter acetylcholine, and is an essential factor for neurons to be cholinergic. We have analyzed regulation of the Drosophila ChAT gene during development by examining the β-galactosidase expression pattern in transformed lines carrying different lengths of 5′ flanking DNA fused to a lacZ reporter gene. The largest fragment tested, 7.4 kb, resulted in the most extensive expression pattern in embryonic and larval nervous system and likely reflects all the cis-regulatory elements necessary for ChAT expression. We also found that 5′ flanking DNA located between 3.3 kb and 1.2 kb is essential for the reporter gene expression in most of the segmentally arranged embryonic sensory neurons as well as other distinct cells in the CNS. The existence of negative regulatory elements was suggested by the observation that differentiating photoreceptor cells in eye imaginal discs showed the reporter gene expression in several 1.2 kb and 3.3 kb transformants but not in 7.4 kb transformants. Furthermore, we have fused the 5′ flanking DNA fragments to a wild type ChAT cDNA and used these constructs to transform Drosophila with a Cha mutant background. Surprisingly, even though different amounts of 5′ flanking DNA resulted in different spatial expression patterns, all of the positively expressing cDNA transformed lines were rescued from lethality. Our results suggest that developmental expression of the ChAT gene is regulated both positively and negatively by the combined action of several elements located in the 7.4 kb upstream region, and that the more distal 5′ flanking DNA is not necessary for embryonic survival and development to adult flies.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 149-151 
    ISSN: 1570-7458
    Schlagwort(e): Lepidoptera ; Satyridae ; wing pattern induction ; food plant quality
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 4
    ISSN: 1432-1440
    Schlagwort(e): Angiotensin I-converting enzyme ; Gene expression ; Sodium chloride ; Heart ; Inbred rats
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We have recently shown that the angiotensin I converting enzyme (ACE) gene is linked to NaCl-loaded blood pressure in the stroke-prone spontaneously hypertensive rat (SHRSP), and that high-NaCl loading selectively stimulates ACE in the aorta of SHRSP but not in normotensive Wistar-Kyoto (WKY) rats. We therefore investigated the relationship between cardiac ACE and the development of hypertension and left ventricular hypertrophy in response to normal- and high-NaCl diet in these rats. ACE mRNA and ACE activity were measured in left ventricular tissue after completion of hemodynamic characterization of the animals. While SHRSP rats increased blood pressure (P〈0.0001) and heart rate (P〈0.005) in response to high NaCl, blood pressure remained unchanged in WKY. Similarly, relative left ventricular weight increased only in SHRSP after high NaCl (P〈0.002). A significant two- to threefold increase of cardiac ACE mRNA and fourfold stimulation of ACE enzyme activity in response to high NaCl was found in both WKY and SHRSP rats (P〈0.005). The induction of ACE gene expression was significantly more pronounced in SHRSP compared to WKY (P〈0.02), whereas no significant strain differences in left ventricular ACE activity were found after either normal- or high-NaCl diet. Thus, arterial blood pressure and left ventricular weight remained unchanged in the WKY rats despite the activation of left ventricular ACE activity after high-NaCl exposure. These results demonstrate that left ventricular ACE activity is equally upregulated in response to high-NaCl in the normotensive and hypertensive strain, independently from the development of hypertension. We conclude that the pretranslational induction of left ventricular ACE with high-NaCl loading may be important both for the regulation of cardiac angiotensins and kinins and for local therapeutic ACE inhibition in the heart during high-salt status.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Neurochemical research 15 (1990), S. 1089-1096 
    ISSN: 1573-6903
    Schlagwort(e): Choline acetyltransferase ; development ; mRNA ; Drosophila
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We have measured the steady state levels of choline acetyltransferase (ChAT, EC 2.3.1.6) mRNA during different developmental stages ofDrosophila melanogaster using a ChAT specific cRNA probe. ChAT mRNA was first detected approximately 6–7 h after oviposition, increased until the 1st–2nd larval instar, decreased into early pupal stages and increased again during late pupation, reaching a maximum in adults. Northern analysis showed a major RNA band with a Mr of 4.7 kilobases and Western analysis also showed a single major 75 kD protein band at all developmental stages. Our results support the hypothesis that a major point of regulation of ChAT expression may be at the transcriptional level.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 16 (1990), S. 1977-1995 
    ISSN: 1573-1561
    Schlagwort(e): Fall armyworm ; Spodoptera frugiperda ; Lepidoptera ; Noctuidae ; corn ; Zea mays ; plant-insect interaction ; amino acids ; herbivory ; feeding resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The free amino acids have been shown by isolational work and choice bioassays to be more important than all other factors evaluated in defining leaf-feeding resistance of corn (Zea mays L.) to fall armyworm (FAW) [(Spodoptera frugiperda J.E. Smith)] larvae. 6-MBOA (6-methoxybenzoxazolinone) and maysin, toxins present in corn, were shown not to be significant factors for leaf-feeding resistance to first-instar FAW larvae because of their low concentrations in the whorl. Amino acid analysis showed that while the ratios of the essential amino acids in susceptible (S) and resistant (R) lines were similar, there were differences in the nonessential amino acids, particularly aspartic acid, which was higher in R lines. Also, the ratio of essential amino acids to nonessential amino acids was important, being too low in expressed whorl leaf juice (obtained from V8–V10 growth stage plants) to support larval growth, although juice was stimulatory in choice tests. The total protein content of whorls in S lines was about 15% higher than in R lines, but the significance of this difference is uncertain, because nutritional tests showed that larval growth increased with total protein only up to 12% protein. Sugars were only slightly stimulatory. Thus, the amino acids along with higher hemicellulose content of R lines, established by us earlier, appear to explain much of the basis of resistance in corn to larval leaf-feeding of the FAW.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1573-1561
    Schlagwort(e): Southwestern corn borer ; Diatraea grandiosella Dyar ; Lepidoptera ; Pyralidae ; corn ; Zea mays L. ; plant-insect interaction ; amino acids ; sugars ; herbivory ; feeding resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The leaf-feeding resistance of corn or maizeZea mays L. to the southwestern corn borer, SWCB,Diatraea grandiosella Dyar has been attributed at least in part to decreased protein, increased crude fiber, and increased hemicellulose in the whorls of resistant genotypes. In this study, individual amino acids and sugars were evaluated as arrestants, with the objective of identifying those that gave weak or negative responses. Several structure-activity relationships were identified. Larvae responded to three-carbonn alkyl alpha amino acids more than to two-, four-, five-, and six-carbon compounds. Amino acids with terminal isopropyl functions gave decreased responses relative to theirn-alkyl counterparts. Dicarboxylic acids and their amides gave the lowest responses of all classes of amino acids. The normally occurring basic amino acids were all good arrestants. The guanido [HN:C(NH2)NH-] function was somewhat important to an arrestant response, as was the number of methylenes between the alpha and omega amino functions of diaminon-alkyl amino acids. Hydroxy amino acids were generally good arrestants unless the hydroxyl was located on a ring system. The two sugars present in expressed corn whorl juice, glucose and fructose, gave poor responses. However, two other sugars, mannose and arabinose, whose C-2 hydroxyls are conformationally in the axial position, were strongly arrestant. Formulated amino acid mixtures based on their content in whorl juice were as strong arrestants as whorl juice. However, the relative contributions of amino acids and sugars that are weak arrestants to the resistance of corn to SWCB larvae is uncertain because amino acid analyses did not reveal significantly higher contents of these amino acids in the whorl juices of resistant lines.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1573-1561
    Schlagwort(e): Cardenolides ; monarch butterfly ; Danaus plexippus L. ; Lepidoptera ; Danaidae ; storage ; regulation ; metabolism ; uscharidin ; calactin ; calotropin ; uzarigenin ; digitoxigenin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Adult monarch butterflies,Danaus plexippus L. (Lepidoptera: Danaidae), store only some of the cardenolides present in the larval milkweed (Asclepiadaceae) host. Feeding known doses of individual cardenolides to 4th instar monarch larvae led to more efficient larval tissue incorporation at low doses than at high ones, and favored storage of cardenolide glycosides over genins. A qualitative regulation also occurs during larval feeding; calactin and calotropin were stored as such but uscharidin was rapidly converted to a mixture of calactin and calotropin which were the forms stored by the larvae. Two genins, uzarigenin and digitoxigenin, were stored by larvae as polar cardenolide metabolites.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Extremophiles 4 (2000), S. 321-331 
    ISSN: 1433-4909
    Schlagwort(e): Key words Cold shock ; Low-temperature adaptation ; Psychrophile ; Adaptive mechanisms ; Antarctic Archaea ; Gene expression ; Protein structure ; Review
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We live on a cold planet where more than 80% of the biosphere is permanently below 5°C, and yet comparatively little is known about the genetics and physiology of the microorganisms inhabiting these environments. Based on molecular probe and sequencing studies, it is clear that Archaea are numerically abundant in diverse low-temperature environments throughout the globe. In addition, non-low-temperature-adapted Archaea are commonly exposed to sudden decreases in temperature, as are other microorganisms, animals, and plants. Considering their ubiquity in nature, it is perhaps surprising to find that there is such a lack of knowledge regarding low-temperature adaptation mechanisms in Archaea, particularly in comparison to what is known about archaeal thermophiles and hyperthermophiles and responses to heat shock. This review covers what is presently known about adaptation to cold shock and growth at low temperature, with a particular focus on Antarctic Archaea. The review highlights the similarities and differences that exist between Archaea and Bacteria and eukaryotes, and addresses the potentially important role that protein synthesis plays in adaptation to the cold. By reviewing the present state of the field, a number of important areas for future research are identified.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Neurochemical research 24 (1999), S. 1081-1087 
    ISSN: 1573-6903
    Schlagwort(e): Choline acetyltransferase ; Drosophila ; Temperature-sensitive mutants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We used the reverse transcription-polymerase chain reaction (RT-PCR) to amplify choline acetyltransferase (ChAT) mRNA fragments from two temperature-sensitive alleles of Drosophila melanogaster, Cha ts1 and Cha ts2. Single base substitutions in the mutants (T1614A in Cha ts1 and G1596A in Cha ts2) would result in amino acid changes for ChAT protein (Met403Lys in Cha ts1 and Arg397His in Cha ts2). These base substitutions were confirmed in mRNA extracted from homozygous mutants using a Single Nucleotide Primer Extension assay (SNuPE) and are sufficient to produce thermolabile enzyme. Our results indicate that these temperature-sensitive mutants are point mutations in the structural gene for ChAT. Using a quantitative SNuPE assay we also show that similar levels of Cha ts and wild type transcripts are present in heterozygous flies (Cha ts1/+ and Cha ts2 /+) at both restrictive and permissive temperatures. This contrasts with RNase protection assays of ChAT mRNA in homozygous mutant animals where the levels of mutant mRNA decrease at restrictive temperature.
    Materialart: Digitale Medien
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