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1.
The neutral mononuclear vanadyl complex with the quinolone antibacterial drug enrofloxacin has been prepared and characterized with physicochemical and spectroscopic techniques and molecular mechanics calculations. The interaction of the complex with calf-thymus DNA has also been investigated and the antimicrobial activity has been evaluated against three different microorganisms.  相似文献   

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During the last 10–15 years significant progress has been achieved in all directions of studies of the glutathione system. A series of new enzymes involved into metabolism of glutathione has been discovered. Many of these enzymes are polyfunctional and their new activities have been recognized. The enzymes interact with hormones and signal transduction systems. Significant progress has been achieved in the studies of intracellular, intercellular and inter-organ transport. The important achievement is employment of not only selective compounds-analyzers but also gene engineering methods for identification of new functions.  相似文献   

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Mycopathologia - Recently, Trichosporon taxonomy has been reevaluated and new genera of the Trichosporonaceae family have been described. Here, 26 clinical isolates were submitted for...  相似文献   

6.
Keratan sulfate: structure, biosynthesis, and function   总被引:7,自引:0,他引:7  
Funderburgh JL 《Glycobiology》2000,10(10):951-958
The last 5 years have seen a marked increase in research on keratan sulfate (KS) and a concomitant increase in our understanding of the range of molecules that carry this adaptable polysaccharide. More than 15 KS-linked proteins have been identified and many of the genes encoding these have been cloned. KS-containing molecules have been identified in numerous epithelial and neural tissues in which KS expression responds to embryonic development, physiological variations, and to wound healing. A corneal cell culture system has been developed in which long-term KS biosynthesis is maintained. Progress has been made toward identification of the glycosyl- and sulfotransferases responsible for KS biosynthesis. A mouse knockout of a corneal KS-proteoglycan has provided the first experimental support for the role of KS in corneal transparency. Evidence has also been presented supporting functional roles of KS in cellular recognition of protein ligands, axonal guidance, cell motility, and in embryo implantation. These findings have served to expand the concept of what keratan sulfate is and the potential roles it may play in the cellular biology of diverse tissues.  相似文献   

7.
Hydroxynonenal,toxic carbonyls,and Alzheimer disease   总被引:5,自引:0,他引:5  
Cytoskeletal disruption is one of the distinguishing characteristics of the vulnerable neurons in Alzheimer disease (AD). It has been suggested that these cytoskeletal changes occur secondarily to covalent modifications of the protein components. Despite the abundance and probable importance of these changes, there has been very little data regarding the identity of the modified proteins or the precise chemistry of the modifications. Here we review a specific type of modification, namely carbonylation of proteins, which has been shown to be a common result of cellular oxidative stress. Hopefully, the following discussion will help elucidate the relationship between oxidative stress, protein modification and the pathogenesis of AD.  相似文献   

8.
The protease which initiates the massive protein degradation early in bacterial spore germination has been purified from Bacillus megaterium spores. The enzyme has a molecular weight of 160,000 and contains four apparently identical subunits, but only the tetramer is enzymatically active. A radioimmunoassay has been developed for this enzyme and has been used to show that the protease is absent from growing cells, but appears early in sporulation within the developing forespore. In contrast, the protease antigen disappears rapidly during spore germination, in parallel with the loss in enzyme activity.  相似文献   

9.
The data reported in the literature concerning the uses and composition of yarrow,Achillea millefolium aggr., Compositae, are compiled and discussed. Historically, this plant has been extensively used as a herbal remedy for numerous afflictions by many cultures on several continents. It has also been the subject of a considerable number of scientific investigations. It has, however, not been previously reviewed. Analysis of available information demonstrates the value of continued phytochemical investigations of folklore remedies.  相似文献   

10.
A major metabolic aberration associated with cancer is a change in glucose metabolism. Isoform selection of the glycolytic enzyme pyruvate kinase has been implicated in the metabolic phenotype of cancer cells, and specific pyruvate kinase isoforms have been suggested to support divergent energetic and biosynthetic requirements of cells in tumors and normal tissues. PKM2 isoform expression has been closely linked to embryogenesis, tissue repair, and cancer. In contrast, forced expression of the PKM1 isoform has been associated with reduced tumor cell proliferation. Here, we discuss the role that PKM2 plays in cells and provide a historical perspective for how the study of PKM2 has contributed to understanding cancer metabolism. We also review recent studies that raise important questions with regard to the role of PKM2 in both normal and cancer cell metabolism.  相似文献   

11.
《Cell biology international》2019,43(12):1523-1523
The above article, published online on 31 October 2017 in Wiley Online Library ( https://doi.org/10.1002/cbin.10907 ), has been withdrawn by agreement with the journal Editor, Sergio Schenkman, and John Wiley & Sons Ltd. The withdrawal has been agreed because the authors have not provided a signed Copyright Transfer Agreement.  相似文献   

12.

This paper provides an overview of research that has been conducted with manganese (Mn), chromium (Cr), nickel (Ni), and boron (B) in poultry, swine, and ruminants. Manganese is an essential trace mineral that functions as an enzyme component and enzyme activator. A deficiency of Mn results in a variety of bone abnormalities, and Mn deficiency signs have been observed under practical conditions in poultry and cattle. Chromium can potentiate the action of insulin, but whether Cr is an essential trace mineral is controversial. Insulin sensitivity has been enhanced by Cr in cattle, swine, and broilers. Responses to Cr supplementation have been variable. Production responses to Cr supplementation have been most consistent in animals exposed to various stressors (heat, cold, weaning, etc). The legality of supplementing Cr to animal diets varies among countries, Cr sources, and animal species. A specific biochemical function for Ni and B has not been identified in mammals. Signs of Ni deficiency have been produced experimentally in a number of animal species. Nickel may affect rumen microbial fermentation in ruminants, as Ni is a component of bacterial urease and cofactor F430 in methanogenic bacteria. There is little evidence that dietary Ni limits animal production under practical conditions. Beneficial effects of B supplementation on growth and bone strength have been seen in poultry and swine, but results have been variable.

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13.
The stability between helical conformations of homopeptides of alanine, glycine, and aminoisobutyric acid has been studied by means of quantum-mechanical methods. The influence of peptide length on the relative stability between helical conformations has also been analyzed by means of systematic studies for peptides of size up to 11 residues. Finally, the influence of the solvent has been examined by using self-consistent reaction field methods. The results provide a detailed picture of the modulation exerted by these factors on the helical preferences of these peptides. © 1997 Wiley-Liss Inc.  相似文献   

14.
The structure of Azotobacter vinelandii ferredoxin I (AvFdI) has been extensively characterized by a variety of techniques. Although its physiological function is unknown, it has long been implicated as being involved in electron donation to nitrogenase. Here we report that the AvFdI gene (fdxA) has been cloned from an EcoRI digest lambda library using a synthetic oligonucleotide probe and that its sequence has been determined. The amino acid sequence deduced from the DNA sequence is identical to the previously published protein sequence. Analysis of the promoter region indicates that AvFdI is not a nif specific gene product. A mutant of A. vinelandii has been constructed which is identical to the wild-type, at the DNA level, except that the fdxA gene has been interrupted by insertion of a kanamycin cartridge. This mutant, called LM100, does not synthesize AvFdI but does synthesize the Fe and MoFe proteins of nitrogenase and grows at wild-type rates under N2-fixing conditions. This demonstrates that AvFdI is not required for N2 fixation by A. vinelandii. There is a small acidic protein, which is present in wild-type A. vinelandii, whose level is dramatically increased in LM100. The nature of this protein is under further investigation.  相似文献   

15.
An unrecognized pentahydroxy bile alcohol has been isolated from the bile and feces of patients with cerebrotendinous xanthomatosis (CTX). Its structure, 5 β-cholestane-3 α, 7 α, 12 α, 25, 26-pentol has been deduced by spectroscopic methods and confirmed by comparison with a synthetic analog.  相似文献   

16.
Diabetes, metallothionein, and zinc interactions: a review   总被引:1,自引:0,他引:1  
Epidemiological evidence, associating diabetes with zinc (Zn) deficiencies, has resulted in numerous research studies describing the effects of Zn and associated metallothionein (MT), on reducing diabetic complications associated with oxidative stress. MT has been found to have a profound effect on the reduction of oxidative stress induced by the diabetic condition. Over expression of MT in various metabolic organs has also been shown to reduce hyperglycaemia-induced oxidative stress, organ specific diabetic complications, and DNA damage in diabetic experimental animals, which have been further substantiated by the results from MT-knockout mice. Additionally, supplementation with Zn has been shown to induce in vivo MT synthesis in experimental animals and to reduce diabetes related complications in both humans and animal models. Although the results are promising, some caution regarding this topic is however necessary, due to the fact that the majority of the studies done have been animal based. Hence more human intervention trials are needed regarding the positive effects of MT and Zn before firm conclusions can be made regarding their use in the treatment of diabetes.  相似文献   

17.
Purification, cloning, and expression of the prolactin receptor   总被引:1,自引:0,他引:1  
The rat liver prolactin receptor has been purified to homogeneity, and partial amino acid sequences have been obtained. The structure of the receptor has been deduced from a single complementary DNA clone. The mature protein of 291 amino acids has a relatively long extracellular region, a single transmembrane segment, and a short (57 amino acids) cytoplasmic domain. With the rat cDNA used as a probe, the prolactin receptor in rabbit mammary gland and human hepatoma cells has also been isolated. These tissues contain a second, longer form of the receptor (592 and 598 amino acids, respectively). Both the short and long forms of the prolactin receptor show regions of strong sequence identity with the human and rabbit growth hormone receptors, suggesting that the prolactin and growth hormone receptors originate from a common ancestor.  相似文献   

18.
Delta sleep-inducing peptide (DSIP) has been found to induce sleep as well as extra-sleep effects. Although the presence of endogenous DSIP-like material has been demonstrated, the metabolic fate of injected DSIP has not been clarified so far. A major obstacle in monitoring degradation of DSIP has been the lack of an easy method to separate DSIP from tryptophan (Trp). Cleavage of the N-terminal Trp apparently represents the first and most important step in the metabolism of the peptide. Adsorption to aluminum oxide has been found to separate the two compounds and optimal conditions for the separation are described. Quantitative determination of the degradation of DSIP in plasma or serum is now rapidly achieved. The method should help to advance metabolic studies of DSIP. Other applications such as extraction of DSIP from solutions are also possible.  相似文献   

19.
The culture concept has been central to anthropology since the formational period of the discipline. Yet for much of the discipline's history it was used without explicit definition. Recent attempts to define it have yielded a range of varied formulations in the subdisciplines of archaeology and sociocultural anthropology. Does this mean that the center of anthropology—shared belief in a unified culture concept—has been destroyed? Quite the opposite, the author concludes—the debate has yielded benefits.  相似文献   

20.
The Giemsa banding patterns of the chromosomes of 4 species of Procyonidae, 13 of Viverridae, and 6 of Felidae have been studied. The patterns have all been related to the basic felid karyotype. Each procyonid and viverrid has a distinctive karyotype, whereas some felids have indistinguishable karyotypes even when banded. Extensive interfamilial G-banding conservatism has been demonstrated, with many chromosomes being "shared" by all three families. A chromosome identification and karyotyping system for the Carnivora has been devised to facilitate comparison of data from future studies. Phylogenetic implications of the findings have been discussed.  相似文献   

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