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951.
In short-term (1 h) uptake experiments GA3(10-5M) stimulated Pi uptake into maize root cortex cells by 28.7 %, Ethrel (10-3M) inhibited it by 18.5 % and BA, IAA, and ABA were inactive. In long-term (5 h) experiments ABA remained inactive, GA3 lost its stimulatory effect, and BA (5. 10-6M), IAA (10-4 -10-5M), and Ethrel (10-3 -5. 10-4M) decreased Pi uptake. When the hormones were present only during 3 h preincubation (“augmentation”) period ABA was inactive, GA3 slightly raised and BA, IAA, and Ethrel slowed down subsequent Pi uptake.
BA(10-7 –10-5M) decreased xylem sap volume flow and Pi translocation. ABA in all tested concentrations (10-8 –10-5M) reduced exudation rate and Pi translocation, its effect declining with time. IAA effect strongly depended on concentration used and on application time
and varied from strong inhibition to moderate stimulation of both volume flow and Pi translocation. GA3 (10-7M) slightly stimulated xylem volume flow but inhibited phosphate translocation. Ethrel (10-4 and 10-5M) increased both parameters, but Pi transloeation much more than volume flow. IAA, BA, and ABA influenced volume flow and P transloeation to the same extent
leaving Pi concentration in the xylem sap unchanged. GA3 and Ethrel influence Pi concentration in the xylem sap and it is thus probable that these hormones regulate release of phosphate ions into the xylem
sap. 相似文献
952.
Michael Hecker Andreas Schroeter Kersten Träder Friedrich Mach 《Archives of microbiology》1986,143(4):400-402
Amino acid-starved cells of Escherichia coli relA
+, which contain a large number of glycogen particles, are able to survive in phosphate buffer for a longer time period than their relaxed counterparts. With regard to NH
4
+
starvation differences in the survival of both strains were not found. NH
4
+
starved cells of E. coli relA are able to synthesize glycogen but amino acid-starved cells of the relA strain are not. We suggest that the synthesis of glycogen triggered by guanosine tetraphosphate during amino acid starvation is responsible for the prolonged viability of the E. coli relA
+ strain.Abbreviations ppGpp
guanosine tetraphosphate 相似文献
953.
HLA-DR polymorphism in a Senegalese Mandenka population: DNA oligotyping and population genetics of DRB1 specificities.
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J M Tiercy A Sanchez-Mazas L Excoffier X Shi-Isaac M Jeannet B Mach A Langaney 《American journal of human genetics》1992,51(3):592-608
HLA class II loci are useful markers in human population genetics, because they are extremely variable and because new molecular techniques allow large-scale analysis of DNA allele frequencies. Direct DNA typing by hybridization with sequence-specific oligonucleotide probes (HLA oligotyping) after enzymatic in vitro PCR amplification detects HLA allelic polymorphisms for all class II loci. A detailed HLA-DR oligotyping analysis of 191 individuals from a geographically, culturally, and genetically well-defined western African population, the Mandenkalu, reveals a high degree of polymorphism, with at least 24 alleles and a heterozygosity level of .884 for the DRB1 locus. The allele DRB1*1304, defined by DNA sequencing of the DRB1 first-domain exon, is the most frequent allele (27.1%). It accounts for an unusually high DR13 frequency, which is nevertheless within the neutral frequency range. The next most frequent specificities are DR11, DR3, and DR8. Among DRB3-encoded alleles, DR52b (DRB3*02) represents as much as 80.7% of all DR52 haplotypes. A survey of HLA-DR specificities in populations from different continents shows a significant positive correlation between genetic and geographic differentiation patterns. A homozygosity test for selective neutrality of DR specificities is not significant for the Mandenka population but is rejected for 20 of 24 populations. Observed high heterozygosity levels in tested populations are compatible with an overdominant model with a small selective advantage for heterozygotes. 相似文献
954.
Göran Andersson Bertil Lindblom Leif Andersson Jack Gorski Bernard Mach Lars Rask 《Immunogenetics》1988,28(1):1-5
In most individuals two HLA-DR
genes are expressed from each chromosome. One of these genes encodes one of the classical DR specificities, while the other encodes either of the supertypic DRw52/DRw53 specificities. In addition to these genes usually one or two DR
pseudogenes are present. In contrast, the DRw8 chromosomal region only contains a single DR
gene. To determine the relationship of this single gene to the multiple DR
genes of other DR specificities, comparisons of Southern genomic blots were carried out. In this analysis genomic clones for each individual DR
chain locus were included. The DR
w8 gene was indistinguishable from the DR
III gene of DR3 cells (encoding DRw52), suggesting that it is closely related to the latter gene. The functional implications of this finding are discussed. 相似文献
955.
Ivana Vančurová Aleš Vančura Jindřich Volc Jiří Neužzil Miroslav Flieger Gabriela Basařová Vladislav Běhal 《Archives of microbiology》1988,150(5):438-440
Alanine dehydrogenase was purified to near homogeneity from cell-free extract of Streptomyces aureofaciens, which produces tetracycline. The molecular weight of the enzyme determined by size-exclusion high-performance liquid chromatography was 395 000. The molecular weight determined by sodium dodecyl sulfate gel electrophoresis was 48 000, indicating that the enzyme consists of eight subunits with similar molecular weight. The isoelectric point of alanine dehydrogenase is 6.7. The pH optimum is 10.0 for oxidative deamination of L-alanine and 8.5 for reductive amination of pyruvate. K
M values were 5.0 mM for L-alanine and 0.11 mM for NAD+. K
M values for reductive amination were 0.56 mM for pyruvate, 0.029 mM for NADH and 6.67 mM for NH4Cl.Abbreviation AlaDH
alanine dehydrogenase 相似文献
956.
957.
Paula?Fernandes?Aguiar Sílvia?Mour?o?Magalh?es Ivana?Alice?Teixeira?Fonseca Vanessa?Batista?da?Costa Santos Mariana?Aguiar?de?Matos Marco?Fabrício?Dias?Peixoto Fábio?Yuzo?Nakamura Craig?Crandall Hygor?Nunes?Araújo Leonardo?Reis?Silveira Etel?Rocha-Vieira Flávio?de?Castro Magalh?es Fabiano?Trigueiro?AmorimEmail author 《Cell stress & chaperones》2016,21(5):793-804
958.
Chemical Composition and in vitro Biological Activities of Essential Oils from Conchocarpus fontanesianus (A. St.‐Hil.) Kallunki & Pirani (Rutaceae)
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This study aimed at assessing the chemical composition of the essential oils from leaves and fruits of Conchocarpus fontanesianus, an endemic Brazilian species of Rutaceae. The plant material was harvested from two regions of the Atlantic rainforest in the State of São Paulo. The volatile compounds in the essential oils were extracted by hydrodistillation (HD), and analyzed by GC/FID and GC/MS, allowing the quantification and identification of 54 components in total, which comprise about 97% of the total oil composition. From the leaves collected in Caraguatatuba and Juréia‐Itatins, the major volatile compounds identified were as follows: spathulenol (22.32% and 16.67%) and α‐cadinol (9.7% and 14.76%). However, β‐myrcene (34.56%), (+)‐epi‐bicyclosesquiphellandrene (8.71%), and bicyclogermacrene (5.80%) were dominant in the fruits collected only in Juréia‐Itatins. The in vitro biological activities were tested to evaluate the cytotoxic, antifungal, and antioxidant potential of essential oils from leaves and fruits. 相似文献
959.
Analysis of salicylic acid‐dependent pathways in Arabidopsis thaliana following infection with Plasmodiophora brassicae and the influence of salicylic acid on disease
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960.
Jelena B. Popović-Djordjević Anita S. Klaus Željko S. Žižak Ivana Z. Matić Branko J. Drakulić 《Journal of enzyme inhibition and medicinal chemistry》2016,31(6):915-923
Antiproliferative and antibacterial activities of nine glutarimide derivatives (1–9) were reported. Cytotoxicity of compounds was tested toward three human cancer cell lines, HeLa, K562 and MDA-MB-453 by MTT assay. Compound 7 (2-benzyl-2-azaspiro[5.11]heptadecane-1,3,7-trione), containing 12-membered ketone ring, was found to be the most potent toward all tested cell lines (IC50?=?9–27?μM). Preliminary screening of antibacterial activity by a disk diffusion method showed that Gram-positive bacteria were more susceptible to the tested compounds than Gram-negative bacteria. Minimum inhibitory concentration (MIC) determined by a broth microdilution method confirmed that compounds 1, 2, 4, 6–8 and 9 inhibited the growth of all tested Gram-positive and some of the Gram-negative bacteria. The best antibacterial potential was achieved with compound 9 (ethyl 4-(1-benzyl-2,6-dioxopiperidin-3-yl)butanoate) against Bacillus cereus (MIC 0.625?mg/mL; 1.97?×?10?3?mol/L). Distinction between more and less active/inactive compounds was assessed from the pharmacophoric patterns obtained by molecular interaction fields. 相似文献