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1.
Recovery of Cell-Bound Interferon   总被引:5,自引:2,他引:3       下载免费PDF全文
Interferon could be recovered from homologous cells to which it was applied but could not be recovered from heterologous cells. The amount of interferon that could be recovered from cells corresponded to the sensitivity of the cells to the antiviral activity of the interferon: mouse embryo fibroblasts, which were 5 to 10 times as sensitive as L-929 cells to interferon, bound 5 to 10 times more interferon than the latter, whereas Lpa cells, which were only one-third as sensitive as L-929 cells to interferon, bound only one-third as much as the latter. The concentration of cell-bound interferon was as much as 150 times the extracellular concentration of interferon applied to the cells. Interferon bound to cells at 4 C with the same efficiency as it did to cells at 37 C, and actinomycin D-treated cells bound interferon as well as normal cells. Even though the total amount of interferon bound to cells was as much as 30% of the amount of interferon applied to them, no loss of antiviral activity was detectable from the medium.  相似文献   

2.
Recent results suggest that the presence of common nitrogen salts (sodium nitrite and nitrate) in the irradiation medium can markedly protect filamentous blue green algae from potentially lethal ultraviolet light irradiation. Our results as well as general biological arguments as presented by Egami (above) support and extend Egami's original view that anaerobic respiratory pathways using nitrite and nitrate as terminal electron acceptors evolved prior to oxygen requiring aerobic respiratory pathways.  相似文献   

3.
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   

4.
A set of modular binary vectors for transformation of cereals   总被引:2,自引:1,他引:1       下载免费PDF全文
Genetic transformation of crop plants offers the possibility of testing hypotheses about the function of individual genes as well as the exploitation of transgenes for targeted trait improvement. However, in most cereals, this option has long been compromised by tedious and low-efficiency transformation protocols, as well as by the lack of versatile vector systems. After having adopted and further improved the protocols for Agrobacterium-mediated stable transformation of barley (Hordeum vulgare) and wheat (Triticum aestivum), we now present a versatile set of binary vectors for transgene overexpression, as well as for gene silencing by double-stranded RNA interference. The vector set is offered with a series of functionally validated promoters and allows for rapid integration of the desired genes or gene fragments by GATEWAY-based recombination. Additional in-built flexibility lies in the choice of plant selectable markers, cassette orientation, and simple integration of further promoters to drive specific expression of genes of interest. Functionality of the cereal vector set has been demonstrated by transient as well as stable transformation experiments for transgene overexpression, as well as for targeted gene silencing in barley.  相似文献   

5.
BACKGROUND: Cathepsin X is a widespread, abundantly expressed papain-like mammalian lysosomal cysteine protease. It exhibits carboxy-monopeptidase as well as carboxy-dipeptidase activity and shares a similar activity profile with cathepsin B. The latter has been implicated in normal physiological events as well as in various pathological states such as rheumatoid arthritis, Alzheimer's disease and cancer progression. Thus the question is raised as to which of the two enzyme activities has actually been monitored. RESULTS: The crystal structure of human cathepsin X has been determined at 2.67 A resolution. The structure shares the common features of a papain-like enzyme fold, but with a unique active site. The most pronounced feature of the cathepsin X structure is the mini-loop that includes a short three-residue insertion protruding into the active site of the protease. The residue Tyr27 on one side of the loop forms the surface of the S1 substrate-binding site, and His23 on the other side modulates both carboxy-monopeptidase as well as carboxy-dipeptidase activity of the enzyme by binding the C-terminal carboxyl group of a substrate in two different sidechain conformations. CONCLUSIONS: The structure of cathepsin X exhibits a binding surface that will assist in the design of specific inhibitors of cathepsin X as well as of cathepsin B and thereby help to clarify the physiological roles of both proteases.  相似文献   

6.
This paper reports the preliminary findings on the reproductive performance of 52 Bhotia women from the Mana Valley (Uttar Pradesh; elevation 10 560 ft.), who had approached menopause. The total amount of time available for reproduction and the total time used for effective reproduction as well as the period, which has been wasted as a result of sociocultural and biological factors, have been calculated. The total time available to Bhotia women for reproduction is found to be 1584 years, out of which 1563 years (98.67%) were used for effective reproduction. The reproductive wastage as a result of socio-economic and biological circumstances is calculated as 21 years only or 0.40 years per woman. All pregnancies as well as lactation operate to reduce fecundability. The various family limiting methods also lower the reproductive performance. A comparison has been made with the results of similar studies in other populations.  相似文献   

7.
Studies of L, D and DL-forms of glutamic acid as the sole nitrogen source or as a supplement to the major nitrogen source--ammonium sulphate have demonstrated that in the first case all forms of glutamic acid are assimilated by auxotrophic mutants--lysine producers. However, the lysine synthesis was very low, when L-glutamic acid was used as the only nitrogen source. Glutamic acid at a concentration of 0.01 M applied as a supplement to the major source of nitrogen acted as a stimulator of lysine synthesis, slightly inhibiting biomass increment. That was true of every form of glutamic acid, especially of DL-glutamic acid.  相似文献   

8.
Derivatives of lactose with the galactose ring substituents replaced by deoxy or acylamino functions were prepared. The 2'-, 3'-, 4'- and 6'-deoxy, 3'-acetamido and 3'-benzamido derivatives of phenyl 4-O-(beta-D-galactopyranosyl)-beta-D-glucopyranoside (phenyl beta-lactoside) were synthesized from disaccharide or monosaccharide precursors. The derivatives were tested as substrates for the N-acetylglucosaminyltransferase from Neisseria meningitidis, which uses lactosyl derivatives as acceptors and UDP-GlcNAc as the donor in a beta-(1-->3) glycosylation reaction. The 6'-deoxy derivative was nearly threefold as active as phenyl beta-lactoside, whereas the 2'- and 4'-deoxy derivatives were less active. The other derivatives were inactive, as expected.  相似文献   

9.
The eye is a unique place for the development of an immune response. Beyond the usual mechanisms of immune restraint, the eye evolved with its exclusive mechanisms such as anterior chamber associated immune deviation. Therefore, immune-mediated inflammation in the eye does not develop at the same pace as in other sites of the body. Here we will address such peculiarities as they regard to ocular autoimmunity, using the experimental autoimmune uveitis as a model to understand the participation of cytokines in the process of aggression against the eye, as well as their immunoregulatory role.  相似文献   

10.
A Segaloff  R B Gabbard 《Steroids》1984,43(1):111-123
Fourteen esters (formate, acetate, propionate, butyrate, hexanoate, heptanoate, and benzoate) located at C-11 of 11 beta-hydroxyesterone and 11 beta-hydroxyestradiol-17 beta were synthesized and evaluated for uterotropic and gonadotropin release inhibition in rats, as well as their ability to displace (3H) estradiol-17 beta from the rat uterine cytosolic estrogen receptor. The most potent uterotropic agent was 11 beta-formoxyestrone which was 1,625 or 2,500 times as active as 11 beta-hydroxyesterone in the uterotropic or gonadotropin release inhibition assay, respectively. 11 beta-Formoxyestrone was 7.5 times as uterotropic as estradiol-17 beta and equal to estradiol-17 beta in inhibiting gonadotropin release. However, the most potent inhibitor of gonadotropin release was 11 beta-acetoxy-estradiol-17 beta which had 133% of the activity of estradiol-17 beta, although it had only 38% of the activity of estradiol-17 beta in the uterotropic assay. Esters larger than the acetoxy group showed sharply decreased activities in either assay. Despite the high estrogenic potency of the 11-formates or 11-acetates, they were rather weak (6% to 35% as active as estradiol-17 beta) in displacing (3H) estradiol-17 beta from the rat uterine cytosolic estrogen receptor.  相似文献   

11.
The use of Kdo thioglycosides as glycosyl donors using DMTST, IBr/AgOTf and NIS/AgOTf as promoters has been evaluated. Activation at low temperature allowed to escape the formation of 2,3-glycal byproducts to give glycosides in high yield and with good beta-anomeric selectivity. The use of diethyl ether as solvent and (especially) isopropylidene acetals as protecting groups improved the alpha-anomeric selectivity. NIS/AgOTf as promoter surprisingly yielded the 3-iodo-product via the glycal intermediate.  相似文献   

12.
The degree of deacetylation (DDA) of chitosan determines the biopolymer's physico-chemical properties and technological applications. pH-Potentiometric titration seems to offer a simple and convenient means of determining DDA. However, to obtain accurate pH-potentiometric DDA values, several factors have to be taken into consideration. We found that the moisture content of the air-dry chitosan samples can be as high as 15%, and a reasonable fraction of this humidity cannot be removed by ordinary drying. Corrections have to be made for the ash content, as in some samples it can be as high as 1% by weight. The method of equivalence point determination was also found to cause systematic variations in the results and in some samples extra acid as high as 1 mol% of the free amino content was also identified. To compensate for the latter effect, the second equivalence point of the titration has to be determined separately and the analytical concentration of the acid be corrected for it. All the corrections listed here are necessary to obtain DDA values that are in reasonable agreement with those obtained from (1)H NMR and IR spectroscopic measurements. The need for these corrections severely limits the usefulness of pH-metry for determining accurate DDA values and thus potentiometry is hardly able to compete with other standard spectroscopic procedures, that is, (1)H NMR spectroscopy.  相似文献   

13.
Studies were carried out on heat treatment of bamboo species Gigantochloa scortechinii Gamble using palm oil. The samples were laminated and glued. The adhesion results showed that the delamination of glue line increased as the temperature and duration of oil heat treatment increased. Maximum load and shear strength of the glue line reduced as the heat treatment become more severe. It was found that the palm oil used as the heating medium penetrated in some parts of the cell wall as well as in the cell lumen of the bamboo.  相似文献   

14.
Cyanobacteria (blue-green algae) are 02-evolving photosynthesizing prokaryotes that have an extensive history of use as a human food source and as a fertilizer in rice fields. They have also been recognized as an excellent source of vitamins and proteins and as such are found in health food stores in North America and elsewhere. Cyanobacteria have a great deal of potential as a source of fine chemicals, as a biofertilizer and as a source of renewable fuel. This potential is being realized as data from research in the areas of the physiology and chemistry of these organisms are gathered and as the knowledge of cyanobacterial genetics and genetic engineering increases. We review, here, the present (and possible future) uses of cyanobacteria and assess the state of the art with respect to the genetic manipulation of cyanobacteria.  相似文献   

15.
In this essay, based on qualitative research with Latino and Irish-American caregivers of demented elders, we argue that spatially and culturally constituted definitions of personhood, the moral life, and justice shape perceptions of normative aging, the agency of the demented persons and their place in the community, the appropriate care of the aged and demented, as well as partially determine the concrete resources which will be available to elders and their families. We review how ties to homelands and neighborhood institutions act as mediators and shapers of anticipatory grief, caregiver burdens, and caregiver resources, serving as a buffer against exhaustion and despair for some families (primarily the Irish-American sample), and as an additional site of loss or stress for others (primarily the Latino sample).  相似文献   

16.
The article presents some data on teaching Biochemistry at the Nature Department of Kharkiv Imperial University Physico-Mathematical Faculty, as well as restoration of biochemical education and scientific researches as a result of the University reorganization in the Soviet period and foundation of the Biochemistry Chair at the Biological Faculty in the renovated Kharkiv State University. The analysis of scientific biochemical investigations conducted in the Kharkiv University till now is revealed. The special attention is paid to development of such a scientific trend as age physiology and biochemistry. The article deals with the comprehensive information on scientific and pedagogical activity of the outstanding scientists such as O. V. Nagorny and I. M. Bulankin as founders of the Kharkiv school of age physiology and biochemistry. The work has utilized some archive data.  相似文献   

17.
张晓蓉 《微生物学报》2011,51(3):297-304
基于发展纳米材料"绿色合成技术"重要性,生物合成纳米材料已成为纳米合成技术研究热点。微生物具有廉价、易培养、繁殖快等优点被应用于多种纳米材料的生物合成研究,成为生物合成纳米材料的重要生物类群。本文综述了细菌、放线菌、酵母菌以及真菌等微生物应用于纳米生物合成技术的发展;着重评述了纳米材料微生物合成生物方法、纳米材料微生物合成相关机制、纳米材料形貌和尺寸微生物调控合成方法以及应用研究进展;并对纳米材料微生物合成技术未来发展趋势进行了展望。  相似文献   

18.
The proteins belonging to different organisms as well as the natural amino acids as incorporated into proteins occurring free in tissues and lymphatic fluids are, as a rule, levorotatory. This article contains a simple explanation of this structural discrimination and of the extremely slow racemization of natural organic substances. Chirality 28:153–157, 2016. © 2015 Wiley Periodicals, Inc.  相似文献   

19.
DNA has been found between bands, in puffs, and in RNA-rich lamellae of bands as dispersed DNA double helices coiled to form secondary helices with a diameter and period of about 400Å. In the bands and heterochromatic regions the secondary helix is further coiled or folded into compact masses. RNA-containing granules are present in interbands and RNA-rich lamellae as well as in puffs. The dispersed DNA of puffs, interbands and the RNA-rich lamellae of bands may all represent the part of the genome that is active in the salivary gland nucleus, while the compact DNA of bands as well as heterochromatic parts may comprise inactive genes.  相似文献   

20.
A possible involvement of glutathione in the detoxication of sulfite   总被引:1,自引:0,他引:1  
Inorganic sulfite may be detoxified by conversion to S-sulfocysteine. We demonstrate this conversion by a series of enzyme-catalyzed steps as follows. Inorganic sulfite reacts with glutathione disulfide by a thiol transferase catalyzed reaction as previously demonstrated. The S-sulfoglutathione formed is then converted by gamma-glutamyltranspeptidase to S-sulfocysteinylglycine and the latter finally hydrolyzed to S-sulfocysteine by a renal dipeptidase. S-Sulfoglutathione is a substrate for gamma-glutamyl-transpeptidase as effective as glutathione itself. Furthermore, S-sulfocysteinylglycine is cleaved as efficiently as cysteinylglycine by a renal dipeptidase at high substrate concentrations but somewhat less efficiently at low substrate concentrations.  相似文献   

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