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61.
A product of microbiological cleavage of the sterols side chain, androsta-1,4-diene-3,17-dione, is toxic for bacteria, in particular, actinobacteria of the genera Mycobacterium and Arthrobacter. Sterols were transformed into androsta-1,4-diene-3,17-dione by culturing the M. neoaurum VKPM An-1656 strain in a high yield, provided that a sorbent was used for elimination of contact between the bacterial cells and the product. Unlike the cholesterol side chain, the more branched chains of phytosterols were cleaved in the presence of M. neoaurum at a high rate only under turbulent stirring of the culture medium, which intensified the formation of hydrocarbonate ion from NaNI3 in situ.  相似文献   
62.
It has been shown that exposure to weak combined collinear magnetic fields (permanent component 42 mT; amplitude of alternating component 40 nT, frequency 3.7 Hz) or millimeter waves with a frequency of 36 GHz and power density of 100 mT/cm2 substantially stimulates the growth of the regeneration blastema in the tail fragment of planaria when the exposure to fields precedes the cutting of the planaria body. This effect is more clearly pronounced during the treatment of planaria with magnetic field. If the treatment with weak physical factors is carried out after the cutting of planaria, the effect of the field is two times less pronounced (exposure to magnetic waves) or is not evident at all (exposure to electromagnetic radiation).  相似文献   
63.
Embryonic cells regulate the expression of matrix metalloproteinases (MMP) providing remodulation of extracellular matrix, which in turn provides the changes in cell adhesion and migration during the cell development and differentiation. In present work we studied the changes of gelatinases (MMP-2 and MMP-9) and collagenases (MMP-1 and MMP-8) activities in the process of cultivating the primary murine embryonic fibroblasts (MEF). Cultivation was continued for 6 passages, after that the culture died in time. According to gelatin and collagen zymography results, drastic changes of all MMPs activities occurred during the third passage of cell cultivation. The MMP-1 and MMP-9 activity appears in the middle of cultivation and then disappeared at the end. The most important event MEF cultivation is appearance and subsequent reservation of collagenase MMP-8 and active form of gelatinase MMP-2.  相似文献   
64.
The region of the clock gene period (per) that encodes a repetitive tract of threonine-glycine (Thr-Gly) pairs has been compared between Dipteran species both within and outside the Drosophilidae. All the non- Drosophilidae sequences in this region are short and present a remarkably stable picture compared to the Drosophilidae, in which the region is much larger and extremely variable, both in size and composition. The accelerated evolution in the repetitive region of the Drosophilidae appears to be mainly due to an expansion of two ancestral repeats, one encoding a Thr-Gly dipeptide and the other a pentapeptide rich in serine, glycine, and asparagine or threonine. In some drosophilids the expansion involves a duplication of the pentapeptide sequence, but in Drosophila pseudoobscura both the dipeptide and the pentapeptide repeats are present in larger numbers. In the nondrosophilids, however, the pentapeptide sequence is represented by one copy and the dipeptide by two copies. These observations fulfill some of the predictions of recent theoretical models that have simulated the evolution of repetitive sequences.   相似文献   
65.
The therapeutic efficacy of enterocin S760, a broad spectrum antimicrobial peptide produced by Enterococcus faecium LWP760 was tested on mice infected with Bacillus anthracis M-71 to induce anthrax (second Tsenkovsky's vaccine). Intraperitoneal four-, two- or one-fold administration of the peptide in a dose of 25 mg/kg for 10 days for prophylactic (1 hour after the contamination) and therapeutic (24 hours after the contamination) purposes prevented or cured the infection in 90-100% of the mice versus the 100-percent lethality in the control (untreated animals). The antimicrobial activity of enterocin S760 against B. anthracis M-71 in vivo correlated with activity in vitro. Enterocin S760 is considered a novel promising antimicrobial for the treatment of grampositive and gramnegative infections.  相似文献   
66.
DNA was found to be cleaved in neutral solutions containing arenes and copper (II) salts. The reaction is comparable in efficiency with the DNA cleavage by such systems as Cu(II)-phenanthroline and Cu(II)-ascorbic acid, but, in contrast to the latter, the system Cu(2+)-arene does not require the presence of an exogenous reducing agent or hydrogen peroxide. The system Cu(2+)-arene does not cleave DNA under anaerobic conditions. Catalase, sodium azide, and bathocuproine, which is a specific chelator of Cu(I), completely inhibit the reaction. The data obtained allow one to suppose that Cu(I) ions, superoxide radical, and singlet oxygen participate in the reaction. It has been shown by the EPR method using spin traps that the reaction proceeds with formation of alkoxyl radicals, which can insert breaks in the DNA molecule. For effective cleavage of DNA in the Cu(II)-o-bromobenzoic acid system, the radicals have to be generated by a specific copper-DNA-o-bromobenzoic acid complex, in which copper ions are most probably coordinated with oxygen atoms of the DNA phosphate groups. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2003, vol. 29, no. 6; see also http://www.maik.ru.  相似文献   
67.
In this study, the structure of egg capsules of two species of Neotropical Perlidae: Anacroneuria starki Fenoglio and Morisi (2001 a) and A. talamanca Stark (1998), were examined. Eggs were studied using a scanning electron microscope. A morphological characterization of these eggshells is presented: layers, attachment structures and other anatomical features are described. The egg capsules of the two species differ in some aspects, but both are characterized by thin-layered egg coverings (vitelline envelope, chorion and extrachorion). On the basis of these observations, the importance of eggshell structure for the biogeographical distribution of Plecoptera in the tropics is discussed. A key role for egg capsules in the adaptation process of Plecoptera to aquatic environments of the Neotropics is hypothesized.  相似文献   
68.
Increased environmental pollution and unhealthy lifestyle are blamed for escalated chronic diseases. Exposure to aflatoxins was recently suggested to have a role in the increased incidence of type 2 diabetes mellitus. Diet modification and consumption of different functional food are now gaining attention, especially in diabetes management. This study investigates the effect of a diet containing barley microgreen against diabetes induced by streptozotocin with or without aflatoxin administration in rats. Barley microgreen was rich in 3′-Benzyloxy-5,6,7,4′-tetramethoxyflavone (48.8% of total) followed by 5β,7βH,10α-Eudesm-11-en-1α-ol (18.46%). Streptozotocin injection and/or aflatoxin administration significantly elevated glucose level, decreased insulin level, decreased β-cell function, deteriorated liver and kidney function parameters, and induced oxidative stress in the liver. Histopathology revealed irregular small-sized islets and decreased area % of insulin-positive beta cells in the pancreas, hepatic degeneration, nephropathy, and neuropathy in diabetic and/or aflatoxin administered rats compared to control. Barley microgreen diet fed to diabetic rats with or without aflatoxin alleviated all evaluated parameters. Barley microgreen diet also ameliorated the toxic effect of aflatoxin. In conclusion, exposure to aflatoxin aggravated diabetes and its complication. The incorporation of barley microgreen in the diet was able to control type 2 diabetes mellitus and the improved outcomes observed with barley microgreen treatments involved or occurred in conjunction with improved biomarkers of oxidative stress.  相似文献   
69.
The results of proper investigations received under the cytogenetic examination of 225 persons (control groups, Chernobyl liquidators exposed to different radiation doses, oncogematology patients) had been summarized and analyzed. The conclusion concerning possibilities and limitations of FISH technique usage for retrospective biodosimetry of human radiation exposure has been presented.  相似文献   
70.
In the article the results of the influence of some types of biological molecules and their specific immune complexes on the volt-amperic characteristics of surface-barrier contact structures with the super thick metal film are presented. Moreover, the possibility to develop on this basis a simple instrumental method for separate registration of initial components and products of their interaction is discussed. It was shown that the volt-amperic characteristics of surface-barrier structures of Ni-Si changed at the deposition of myoglobin and its specific monoclonal antibodies. These structures more essentially reacted to the formed presence of specific immune complex and, in particular, to the direct formation of this complex on the surface at the subsequent use of the initial immune components in comparison with their separate presence. For all investigated types of biological molecules and their specific complexes we found optimal thickness of metal film when changes of volt-amperic characteristics of system achieved maximum level. It was concluded that this electrometrical method was suitable for the express and separation free registration of specific immune complex.  相似文献   
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