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131.
Isopropylidenation of lactose with 2,2-dimethoxypropane in the presence ofp-toluenesulfonic acid gave two products, which were identified by1H- and13C-NMR as 2,35,63,4-tri-O-isopropylidenelactose dimethyl acetal (1) and its 6-O-(2-methoxy)-isopropyl derivative (2). These products were used for the synthesis of 2-O-methyllactose (7), 2,6-di-O-methyllactose (9) and 2-O-benzyllactose (13). 相似文献
132.
Peter J. Brown 《Human ecology: an interdisciplinary journal》1986,14(3):311-332
The concept of adaptation has been used differently in studies of biological and cultural evolution, and this divergence raises the question of whether genetic and cultural adaptations are truly comparable. This paper compares genetic and cultural traits associated with endemic malaria in Sardinia, Italy. Thalassemia and G-6-Pd deficiency, two genetic traits of the Island's population, are believed to enhance fitness against malaria, despite increased risk for the diseases of thalassemia major and favism. Two cultural traits, a pastoral pattern of inverse transhumance and rules limiting the geographical mobility of lowland women, limited exposure to the malaria vector, Anopheles labranchiae; these are used as examples of cultural adaptations. The distribution, costs, and benefits of the adaptive cultural and genetic traits are compared, and the theoretical difficulties of finding a common measure of adaptive value are discussed. 相似文献
133.
Summary The distribution and characterization of the opioid octapeptide met5-enkephalin-arg6-gly7-leu8 (met5-enk-arg6-gly7-leu8) within the gastrointestinal tract of the rat has been determined by immunohistochemistry and radioimmunoassay by use of a newly developed antibody to met5-enk-arg6-gly7-leu8. With both techniques, met5-enk-arg6-gly7-leu8-immunoreactivity (met5-enk-arg6-gly7-leu8IR) was detected in all regions of the gastrointestinal (GI) tract except the esophagus. The highest concentration of immunoreactive met5-enk-arg6-gly7-leu8 was observed in the colon, while intermediate concentrations were found in the stomach, duodenum, jejunum, and ileum. Immunostained somata were observed chiefly in the myenteric plexus; immunostained processes were present primarily in the myenteric plexus and the circular muscle layer. This distribution pattern is similar to that previously observed with antiserum to met5-enkephalin-arg6-phe7 (met5-enk-arg6phe7). Chromatographic analysis of met5-enk-arg6-gly7leu8-immunoreactive peptides extracted from the GI tract revealed the presence of an immunoreactive peptide of high molecular weight which accounted for approximately three-quarters of met5-enk-arg6-gly7-leu8-IR in both stomach and colon. These findings suggest a role for peptides related to the octapeptide met5-enk-arg6-gly7-leu8 in the regulation of GI function. 相似文献
134.
P. C. Banerjee 《Archives of microbiology》1986,144(4):405-407
Phosphoglucose isomerase negative mutant of mucoid Pseudomonas aeruginosa accumulated relatively higher concentration of fructose 1,6-bisphosphate (Fru-1,6-P2) when mannitol induced cells were incubated with this sugar alcohol. Also the toluene-treated cells of fructose 1,6-bisphosphate aldolase negative mutant of this organism produced Fru-1,6-P2 from fructose 6-phosphate in presence of ATP, but not from 6-phosphogluconate. The results together suggested the presence of an ATP-dependent fructose 6-phosphate kinase (EC 2.7.1.11) in mucoid P. aeruginosa.Abbreviations ALD
Fru-1,6-P2 aldolse
- DHAP
dihydroxyacetone phosphate
- F6P
fructose 6-phosphate
- G6P
glucose 6-phosphate
- Gly3P
glyceraldehyde 3-phosphate
- KDPG
2-keto 3-deoxy 6-phosphogluconate
- PFK
fructose 6-phosphate kinase
- PGI
phosphoglucose isomerase
- 6PG
6-phosphogluconate 相似文献
135.
Analysis of the energy metabolism after incubation of Saccharomyces cerevisiae with sulfite or nitrite 总被引:1,自引:0,他引:1
After addition of 5 mM sulfite or nitrite to glucose-metabolizing cells of Saccharomyces cerevisiae a rapid decrease of the ATP content and an inversely proportional increase in the level of inorganic phosphate was observed. The concentration of ADP shows only small and transient changes. Cells of the yeast mutant pet 936, lacking mitochondrial F1ATPase, after addition of 5 mM sulfite or nitrite exhibit changes in ATP, ADP and inorganic phosphate very similar to those observed in wild type cells. They key enzyme of glucose degradation, glyceraldehyde-3-phosphate dehydrogenase was previously shown to be the most sulfiteor nitrite-sensitive enzyme of the glycolytic pathway. This enzyme shows the same sensitivity to sulfite or nitrite in cells of the mutant pet 936 as in wild type cells. It is concluded that the effects of sulfite or nitrite on ATP, ADP and inorganic phosphate are the result of inhibition of glyceraldehyde-3-phosphate dehydrogenase and not of inhibition of phosphorylation processes in the mitochondria. Levels of GTP, UTP and CTP show parallel changes to ATP. This is explained by the presence of very active nucleoside monophosphate kinases which cause a rapid exchange between the nucleoside phosphates. The effects of the sudden inhibition of glucose degradation by sulfite or nitrite on levels of ATP, ADP and inorganic phosphate are discussed in terms of the theory of Lynen (1942) on compensating phosphorylation and dephosphorylation in steady state glucose metabolizing yeast.Abbreviations ATP
adenosine triphosphate
- ADP
adenosine diphosphate
- AMP
adenosine monophosphate
- Pi
inorganic orthophosphate
Dedicated to Prof. Dr. Hans Grisebach on the occasion of his sixtieth birthday 相似文献
136.
Annie Conter Dominique Dupouy Christine Delteil Hubert Planel 《Archives of microbiology》1986,144(3):286-290
Previous results from this laboratory have shown that very low chronic doses of gamma radiation can stimulate proliferation of the Cyanobacterium Synechococcus lividus. This modification of cell proliferation occurred during the first doubling. In this paper, we have compared the metabolism of cells cultivated in a normal environment or under chronic irradiation. Incubation of the cells in a new medium induced a high superoxide dismutase (EC 1.15.1.1, SOD) activity at the 18th hour and a degradation of phycocyanin, thus demonstrating that cells were submitted to a photooxidative stress. This increase in superoxide dismutase activity was followed by concomittant peaks of glutathione reductase (EC 1.6.4.2, GR) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49, G6P-DH) at the 24th hour. Irradiated cultures at a dose of 53.5 mGray/year show an earlier and higher peak of SOD, GR, and G6P-DH. In a second stage, cultures showed an earlier onset of photosynthesis under irradiation, as evidenced by an increase in pigment content and an enhancement of glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13, GAP-DH). These results show that the radiostimulation is related to the activation of enzymes protecting against peroxides that were induced under oxidative circumstances and to the activation of a glucose catabolism via the oxidative pentose phosphate pathway.Abbreviations mGy
milli-Gray
- SOD
superoxide dismutase
- G6P-DH
glucose-6-phosphate dehydrogenase
- GAP-DH
glycer-aldehyde-3-phosphate dehydrogenase
- GSSG
oxidized glutathione 相似文献
137.
Eight flavonoids, four 6-oxygenated flavones, two methyl ethers of luteolin, apigenin 6,8-C-diglucoside and quercetin 3-O-glucoside,
were isolated fromNama lobbii andN. rothrockii, sole members of sects.Arachnoidea andCinerascentia, respectively. Both taxa diverge markedly from other namas in morphology and chromosome number and their placement inNama has been questioned. The occurrence of 6-oxygenated flavones in these taxa adds to their already distinctive nature. Flavonoid
evidence argues that both are more closely allied toEriodictyon than either is toNama. 相似文献
138.
K. Manning 《Planta》1986,168(1):61-66
The relationship between ethylene production and the CN--assimilating enzyme -cyanoalanine synthase (CAS; EC 4.4.1.9) was examined in the carnation (Dianthus caryophyllus L.) flower. In petals from cut flowers aged naturally or treated with ethylene to accelerate senescence the several hundred-fold increase in ethylene production which occurred during irreversible wilting was accompanied by a one- to twofold increase in CAS activity. The basal parts of the petal, which produced the most ethylene, had the highest CAS activity. Studies of flower parts (styles, ovaries, receptacles, petals) showed that the styles had a high level of CAS together with the ethylene-forming enzyme (EFE) system for converting 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. The close association between CAS and EFE found in styles could also be observed in detached petals after induction by ACC or ethylene. Treatment of the cut flowers with cycloheximide reduced synthesis of CAS and EFE. The data indicate that CAS and ethylene production are associated, and are discussed in relation to the hypothesis that CN- is formed during the conversion of ACC to ethylene.Abbreviations ACC
1-aminocyclopropane-1-carboxylic acid
- AVG
aminoethoxyvinylglyoine
- CAS
-cyanoalanine synthase
- CHI
cycloheximide
- EFE
ethylene-forming enzyme 相似文献
139.
Inhibition of ornithine decarboxylase induces embryonal carcinoma cell differentiation 总被引:2,自引:0,他引:2
J Schindler M Kelly P P McCann 《Biochemical and biophysical research communications》1983,114(1):410-417
Murine embryonal carcinoma cells can be induced to differentiate in vitro by various physical and chemical means. We report here that inhibition of ornithine decarboxylase activity with a specific enzyme-activated inhibitor, alpha-difluoromethylornithine, can induce differentiation in embryonal carcinoma cells. The differentiated phenotype can be distinguished from undifferentiated embryonal carcinoma cells by altered cellular morphology, biochemical and cell surface antigenic properties. These results suggest that alterations in the levels of cellular polyamines may play a role in embryonal carcinoma cell differentiation. 相似文献
140.
Isolation and characterization of a human interleukin 2 gene 总被引:1,自引:0,他引:1
S Mita S Maeda K Obaru N Nishino K Shimada T Hirano K Onoue T Ogawa H Ogawa 《Biochemical and biophysical research communications》1983,117(1):114-121
An interleukin 2 (IL-2) gene was isolated from a Charon 4A human gene library. Electron microscopic examination of 15 heteroduplexes formed between the genomic DNAs and the IL-2 cDNAs demonstrated that the size of the IL-2 gene is about 5.1 +/- 0.5 kb and that there are at least two introns in this gene. Nucleotide sequence of the 5' flanking region of the IL-2 gene showed a homology with that of the corresponding region of the human immune interferon gene. 相似文献