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1.
4-Aminobutyrate aminotransferase (GABAT) from Pseudomonas aeruginosa was purified 64-fold to apparent electrophoretic homogeneity from cells grown with 4-aminobutyrate as the only source of carbon and nitrogen. Purified GABAT catalyzed the transamination of 4-aminobutyrate, N2-acetyl-L-ornithine, L-ornithine, putrescine, L-lysine, and cadaverine with 2-oxoglutarate (listed in order of decreasing activity). The enzyme is induced in cells grown on 4-guanidinobutyrate, 4-aminobutyrate, or putrescine as the only carbon and nitrogen source. Cells grown on arginine or on glutamate contained low levels of the enzyme. The regulation of the synthesis of GABAT as well as the properties of the mutant with an inactive N2-acetyl-L-ornithin 5-aminotransferase suggest that GABAT functions in the biosynthesis of arginine by convertine N2-acetyl-L-glutamate 5-semialdehyde to N2-acetyl-Lornithine as well as in catabolic reactions during growth on putrescine or 4-guanidinobutyrate but not during growth on arginine.  相似文献   

2.
In previous studies on the acidogenic phase of anaerobic fermentation of lactose, a pathway for the reaction and a rate equation have been proposed. The question then remained as to the effect of the protein in whole whey on the mechanism and on the overall organic substrate conversion. In this study, it was found that as much as 70% of the protein was broken down in the acidogenic reactor. Radiotracer tests showed that the inclusion of protein had no effect on the reaction pathway for lactose degradation. Thus, the whole sweet cheese whey can be fermented as efficiently as whey from which the protein has been removed.  相似文献   

3.
The paper provides a generalization of data and the results of own experiments on influence ovarian steroids on the hypothalamus and other brain areas related to reproduction. Ovarian hormones have widespread effects throughout the brain: on catecholaminergic neurons and serotonergic pathways and the basal forebrain cholinergic system, as well as the hipocampus, spinal cord, nigrostriatal and mesolimbic system, in addition to glial cells and blood-brain barrier. The widespread influences of these various neuronal systems ovarian steroids have measurable effects on mood and affect as well as on cognition, with implications for dementia. There are developmentally programmed sex differenced in hippocampal structure that may help to explain differences in the strategies which male and female rats use to solve spatial navigation problems. The multiple sites and mechanisms of estrogen action in brain underlie a variety of importants effects on cognitive and other brain functions--coordination of movement, pain, affective state, as well as possible protection in Alzheimer's disease. Estrogen withdrawal after natural or surgical menopause can lead to a host of changes in brain function and behavior.  相似文献   

4.
Production of Reference Enteroviruses   总被引:1,自引:1,他引:0       下载免费PDF全文
Forty-five human enterovirus reagents of certified purity and quality were prepared for use as seed viruses and as immunizing antigens. One of the reagents was ampouled as "untreated" seed virus, whereas 14 were ampouled as "MgCl(2)-stabilized" reagents. The remaining 30 reagents were ampouled as "untreated" seed viruses and as "MgCl(2)-stabilized" reagents. Thirty of the reagents were propagated on primary African green monkey kidney cells, 3 on primary baboon kidney cells, 3 on primary rhesus monkey kidney cells, and the remaining 9 on human amnion cells. Forty-two of the viral antigens were concentrated for use in the production of high-titered specific antisera in large animals.  相似文献   

5.
Data on influence of Francisella tularensis C-complex preparations on formation of immunity against tularemia are presented. Study of cellular immunity characteristics as well as dynamics of antibody response was carried out on white mice and guinea pigs models. Absence of toxicity, pyrogenicity, and negative effects on immunocompetent cells in combination with protective activity points to possibility of use the C-complex as a component of a subunit vaccine.  相似文献   

6.
A range of fungicides and herbicides was tested against Gaeumannomyces graminis (causal agent of take-all) on agar plates, and on wheat seedlings in pots and in liquid culture. Benomyl, the standard in all tests, was consistently most effective: like iprodione, nuarimol and KWG 0599 , it diminished infection from inoculum placed just below the seeds more effectively when applied as a drench than as a soil-mix. Benomyl as a soil-mix was most effective in soils with least organic matter. Some compounds toxic to the pathogen on agar plates and in plants grown in liquid culture were ineffective as soil treatments. The practical limitations of soil treatment with conventional fungicides and application methods are discussed.  相似文献   

7.
In the rats fed on lactose-containing purified diet (PDL), bifidobacteria remarkably increased in number in both the jejunum and cecum as compared with those fed on control diet (PD) or conventional diet (NMF). Besides, lactobacilli, streptococci, staphylococci, and Escherichia coli increased in number in the jejuna and/or ceca of rats fed on PDL as compared with those fed on PD. The incidence and numbers of Lactobacillus species were remarkably different between the rats fed on PDL and those on any of the other diets. Indole-producing Bacteroides spp. were rarely isolated from the PDL-fed rats. The cecum was markedly enlarged in the PDL rats and reduced in the PD rats as compared with that in the NMF animals.  相似文献   

8.
In 111 skulls and in saw-cuts of 119 pairs of the temporal bones of persons belonging to various age groups, age and individual changeability of the volume, form, thickness and foramina in the wall of the jugular fossa have been studied. During the postnatal period the jugular fossa increases in its volume twice and average meaning of its volume predominates on the right in the all age groups. The deepest place of the jugular fossa in more than half cases is displaced backward and laterally. The jugular fossa wall in the area of the inferior wall of the tympanic cavity is less thick on the right than on the left side. The foramina in the inferior wall of the tympanic cavity are found in mature persons in 6%, on the right 3 times as often as on the left; in children of younger age--in 45% and on the right more than 2 times as often as on the left.  相似文献   

9.
The escape of several enzymes from “ammonia catabolite repression” in gdhA? (NADP-linked glutamate-dehydrogenase-less) mutants, as well as in gdhCR mutants of Saccharomyces cerevisiae, does not involve glutamine synthetase, either as a positive or as a negative control element. A glutamine-synthetase-less mutant (gln?) was used in this demonstration.In addition to its derepressing effect on the NAD-linked glutamate dehydrogenase, the gdhCR mutation releases “nitrogen catabolite repression” on arginase and allatoinase, as well as glutamine repression on glutamine synthetase. A gdhCS mutation was used to demonstrate that these effects are not mediated through the NAD-linked glutamate dehydrogenase.  相似文献   

10.
The effect of pH on the structure of the communities of anoxygenic-phototrophic-bacteria (APB) was studied under laboratory conditions. Samples of natural APB communities were inoculated into media that differed in pH values, which were 7, 9.5, or 10.5. The structure of the APB communities in the obtained enrichment cultures depended on the pH values and on the mineralization levels of the media, which were the same as in the lakes from which samples were taken. The same dependence of the community structure on salinity was observed as in the case of the natural communities that had been described previously. APB were most diverse in the enrichment cultures grown at pH 9.5. The shift of the pH to either neutral or extremely alkaline values affected the species diversity within the APB community, resulting in marked predominance of the most adapted forms. It was shown that the status of Ectothiorhodospira within the community could serve as an indicator of both salinity and pH in soda lakes with a water mineralization of higher than 5 g/l. The statuses of various APB groups in the community as dependent on pH and salinity are discussed, as well as possible changes in these statuses due to changes in the water level and other environmental parameters in the studied lakes.  相似文献   

11.
The effect of an additional carbon source, lactate, on Penicillium camembertii growth on glutamate as both carbon and nitrogen sources was examined. Glutamate (and lactate) was present in excess in both media. Throughout the whole culture, similar growth time-courses were recorded on both media, indicating the absence of a lactate effect on growth. During the first part of growth, corresponding to an increasing amount of viable biomass, the rate of glutamate consumption remained high, as well as the related ammonium production, indicating its use as a carbon source in addition to being nitrogen source. The low growth rates recorded during the last part of growth resulted in low glutamate consumption, while lactate consumption continued mainly by a maintenance mechanism for the energy supply. A clear differentiation appeared therefore between the carbon source and the energy source: glutamate was mainly used as C source (and N source) for biosynthesis, while lactate was mainly assimilated for energy supply. Carbon and nitrogen yield examinations confirmed this result. Indeed, the C/N ratio found for P. camembertii cellular material (8.14) was about twice that of glutamate (4.29). From this, about half of the available nitrogen was used for biomass formation during growth on glutamate-lactate based medium, as experimentally confirmed (constant yield nitrogen from biomass on nitrogen from glutamate was found (0.49), while the excess nitrogen was released as ammonium). The constant and close to unit (0.99) yield carbon from CO2 on carbon from lactate, also recorded during growth on glutamate-lactate based medium, confirmed that lactate was mainly used as an energy source.  相似文献   

12.
近年来,通过阿米巴共培养等方法发现了一批新的病毒,统称为巨大病毒(giant virus)。它们分布广泛,不仅有很大的病毒颗粒,基因组也非常庞大,还编码许多与蛋白质合成相关的基因,突破了人们对病毒的一般认识,引发了对病毒起源和本质的讨论。巨大病毒被认为有潜在致病性。本文综述了在人体中针对两类最早发现的巨大病毒--拟菌病毒(Mimivirus)和马赛病毒(Marseillevirus)开展的血清学、分子生物学、宏基因组检测、病毒分离及其对哺乳动物感染和致病性研究的进展  相似文献   

13.
In the clinical trials of vaccine TEOVac in lower and reglamented doses under the conditions of remote vaccination, carried out on 11 volunteers, local reactions in the form of hyperemia, gingival edema (1 vaccinee), faucial hyperemia, enlargement of submaxillary lymph nodes (2 vaccinees) were registered in some of the vaccines; in one vaccinee systemic postvaccinal reaction of medium gravity was observed. Revaccination produced no negative effect on the hematological and biochemical characteristics of the blood, as well as on the urine characteristics. The study of the sensitizing vaccine to the antigens of the accumulation substrate (chick embryo), as well as its influence on the development of autoimmune reactions, revealed the absence of the allergic action of the preparation and its influence on autoimmune processes in the vaccines. The trial of the smallpox vaccine in tablets under the conditions of the primary immunization of adults was the topical and most promising trend in the improvement of smallpox vaccination, as the preparation TEOVac proved to be safe, in contrast to the traditional smallpox vaccine introduced by the scarification method, for both vaccines and nonimmunized persons having contacts with them.  相似文献   

14.
Recent advances in generating active proteins through refolding of bacterial inclusion body proteins are summarized in conjunction with a short overview on inclusion body isolation and solubilization procedures. In particular, the pros and cons of well-established robust refolding techniques such as direct dilution as well as less common ones such as diafiltration or chromatographic processes including size exclusion chromatography, matrix- or affinity-based techniques and hydrophobic interaction chromatography are discussed. Moreover, the effect of physical variables (temperature and pressure) as well as the presence of buffer additives on the refolding process is elucidated. In particular, the impact of protein stabilizing or destabilizing low- and high-molecular weight additives as well as micellar and liposomal systems on protein refolding is illustrated. Also, techniques mimicking the principles encountered during in vivo folding such as processes based on natural and artificial chaperones and propeptide-assisted protein refolding are presented. Moreover, the special requirements for the generation of disulfide bonded proteins and the specific problems and solutions, which arise during process integration are discussed. Finally, the different strategies are examined regarding their applicability for large-scale production processes or high-throughput screening procedures.  相似文献   

15.
苹果蠹蛾Cydia pomonella(L.)是全球温带地区果园主要害虫之一,是中国的重要检疫性有害生物,对我国苹果、梨等水果的安全生产造成极大危害及威胁。为详细了解苹果蠹蛾的产卵特性,从而为进行有效的监测与防控提供基础信息,作者于2006年在甘肃省山丹县梨果园中对树冠不同高度与朝向的蛀果率进行了调查,并于2010在内蒙古阿拉善左旗对梨树果枝上不同部位的产卵量进行了详细调查。主要研究结果如下:1)树冠2.5m以上的蛀果率显著高于2.5m以下的蛀果率,树冠东面的蛀果率最高,南面的蛀果率最低;2)在整个果园中,靠近北侧的果树上果实受害程度要高于南侧果树上的果实受害程度,整个果园中蛀果率由北向南逐渐降低;3)叶片上的卵数最多,占总卵数的73.1%,果实上的卵数次之,占总卵数的14.6%,枝条上的卵数最少,占总卵数的12.2%;4)在产卵的叶片上,卵主要产在叶背面,叶片背面卵量是叶正面的6.65倍。鉴于以上研究结果,在开展化学防治或颗粒体病毒防治时,应注意充分喷施果树上层树冠,且在对果实进行处理的同时,叶片和枝条也需要充分喷药。  相似文献   

16.
The review analyzes data on activities and characteristics of proteinases of digestive system and of cathepsins of various tissues in potential preys of fish differing by the character of feeding. There are presented data on multiple forms and molecular mass of proteinases, species-related differences, dependence of proteinase activities on the life cycle stages, type of nutrition, and biochemical food composition as well as on temperature and pH optima. Role of cathepsin in evolution of enzymatic systems providing degradation of food protein components in fish is discussed.  相似文献   

17.
Seminal plasma is a mixture of secretions produced in the testes, epididymides and accessory sex glands, and ejaculated as several consecutive fluid fractions. The composition of seminal plasma and the effects on sperm longevity vary between fractions and individual stallions. This review focuses on the sequence of ejaculation, constituents of seminal plasma and their potential use as fertility markers as well as the influence of seminal plasma on spermatozoa during storage.  相似文献   

18.
The results of the comparative analysis of the cytokine inducing activity of Yersinia pestis EV antigens are presented. Y. pestis fraction 1A (F1A) and lipopolysaccharide (LPS) were shown to induce mono- and neutrophilokines, regulating cooperative interaction of phagocytes in the process of immunity formation to plague. Neutrophilokines and monokines exceed in their capacity for inducing F1A such acknowledged inductor as Escherichia coli LPS. As revealed by the comparative evaluation of Y. pestis EV LPS and E. coli LPS, neutrophilokines synthesized under the action of the former preparation, have greater influence on the inhibition of the macrophage migration from the infection focus as well as on digestive activity of these cells (in secondary immune response) and on the labilization of the lysosome membranes of macrophages than neutrophilokines induced by E. coli LPS. At the same time they produce a lesser modulating effect on the killer and chemotactic activity of neutrophils, as well as on the expression of FC receptors (FcR) on their surface in comparison with monokines, synthesized under the influence of E. coli LPS.  相似文献   

19.
Although traditionally associated with reproductive processes, relaxin is emerging as an important player in renal and cardiovascular function. Much of our recently acquired understanding of relaxin in this new context has arisen from studies of maternal renal and cardiovascular adaptations to pregnancy in rats where the hormone is turning out to be an important mediator. First, we highlight the influence of relaxin on renal hemodynamics and glomerular filtration rate, as well as on other peripheral circulations. Second, we discuss the effect of relaxin on both the steady and pulsatile systemic arterial load, as well as on the heart, in particular, coronary blood flow. Third, we consider the impact of the hormone on cultured endothelial and vascular smooth muscle cells. Fourth, we address the interaction of relaxin with renal and cardiac disease, as well as its role in angiogenesis. Finally, in Perspectives, we point out several key research questions in need of investigation that relate to a potential autocrine/paracrine role of relaxin in renal and cardiovascular tissues. Furthermore, on the basis of its potent vasodilatory and matrix-degrading attributes, we speculate about the therapeutic potential of relaxin in renal and cardiovascular diseases.  相似文献   

20.
The review analyzes data on activities and characteristics of proteinases of digestive system and of cathepsins of various tissues in potential preys of fish differing by the character of nutrition. There are presented data on multiple forms and molecular mass of proteinases, species-related differences, dependence of proteinase activities on the life cycle stages, type of nutrition, and biochemical food composition as well as on temperature and pH optima. Role of cathepsin in evolution of enzymatic systems providing degradation of food protein components in fish is discussed.  相似文献   

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