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1.
The effect of 5 tetracyclines on the barrier and transport properties of the small intestine epithelium was studied. The barrier properties were estimated by a change in the ionic selectivity and conductivity of the epithelium, as well as by enterocyte linkage. The current of the short circuit served the characteristics of the Na transport system state. Dimethylchlortetracycline, methacycline and oxytetracycline in concentrations of 10(-7) g/ml decreased the epithelium conductivity and increased the cell linkage. Tetracycline and methacycline in concentrations of 10(-9) g/ml had an analogous effect. The effect was observed 10--20 minutes after the start of incubation with the substance. No effect on the current of the short circuit was observed within the concentrations of 10(-4) to 10(-9) g/ml. It is suggested that the decreased conductivity and increased linkage are due to adsorption of the tetracycline molecules in the region of close cell contacts. 相似文献
2.
Per?GP?EricsonEmail author Ida?Envall Martin?Irestedt Janette?A?Norman 《BMC evolutionary biology》2003,3(1):16
Background
Phylogenetic hypotheses of higher-level relationships in the order Charadriiformes based on morphological data, partly disagree with those based on DNA-DNA hybridisation data. So far, these relationships have not been tested by analysis of DNA sequence data. Herein we utilize 1692 bp of aligned, nuclear DNA sequences obtained from 23 charadriiform species, representing 15 families. We also test earlier suggestions that bustards and sandgrouses may be nested with the charadriiforms. The data is analysed with methods based on the parsimony and maximum-likelihood criteria. 相似文献3.
Malinina IuA Somov AIu 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2003,43(5):552-554
The influence of electromagnetic radiation of industrial frequency on survival, efficiency, physiological parameters of Daphnia magna (Straus) was investigated. The electromagnetic field with intensity of a magnetic component 15 microTl and an electrical one 12 kV/m was generated. The researches were carried out in acute and chronic experiments. The experimental group was exposed to electromagnetic radiation for 8 hours daily for 30 days. As a result of the study it was revealed that the influence of electromagnetic radiation with the given parameters did not have the lethal effect on the test objects. It was found that electromagnetic radiation negatively affected Daphnia fertility. On the average, a real fertility of the Daphnia in the experimental unit was 26.32% compared to the control. The age of puberty in the experiment increased twice in comparison with the control. 相似文献
4.
Somova LM Buzoleva LS Isachenko AS Somov GP 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》2006,(3):36-40
After the prolonged residence (from 1 month to 2 years) in flow soil columns at 6 - 8 degrees C and 18 - 20 degrees C a complex of ultrastructural changes was detected in Y. pseudotuberculosis bacteria, depending on temperature, the duration of residence in the soil and, to a definite extent, on the strain. They were manifested in the form of cell-wall changes, the formation of the capsule and intercellular slime, changes in the ribosomal saturation of cytoplasm and the conformation state of DNA in the nucleoid zone. As the result of adaptation to nutritional deficit storage substances were accumulated in the form of electron-dense inclusions (polyphosphates) and pseudovacuoles (poly-beta-oxibutyric acid). Temperature influenced the process of mitotic division and the state of chromatin in bacteria. The described ultrastructural changes Y. pseudotuberculosis may be regarded as natural adaptive reaction to the altered conditions of their residence. 相似文献
5.
The results of the bacteriological study of material, taken from humans, rodents, hydro-bios and environmental objects (including foodstuffs) in the Primorsky Territory, for the presence of L. monocytogenes bacteria are given. 83 bacterial strains of the genus Listeria were isolated. As revealed in this study, 25 of these strains belonged to L. monocytogenes (30.12%), 8 strains--to L. innocua (9.6%), 6 strains--to L. seeligeri (7.2%) and 2 strains--to L. ivanovii (2.4%). The greatest number of L. monocytogenes was isolated from foodstuffs and environmental objects. Some biological properties of L. monocytogenes were studied, the degree of their pathogenicity and sensitivity to antimicrobial preparations were determined. 相似文献
6.
Relationships between marine diatoms and the bacterium Listeria monocytogenes have been studied by routine algological methods and high-resolution video-enhanced differential interference contrast light microscopy. The study showed that the relationship between the listeria and the benthic diatom Navicula sp. has a parasitic character, whereas the relationship between the listeria and the planktonic diatom Phaeodactylum tricornutum is protocooperative. 相似文献
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Journal of Ichthyology - Complex ecosystem analysis which includes total abundance estimation of its members as well as their quantitative trophic relationships gives an insight to ecosystem... 相似文献
10.
EA Dukhanina TI Lukyanova EA Romanova V Guerriero NV Gnuchev GP Georgiev DV Yashin LP Sashchenko 《Cell cycle (Georgetown, Tex.)》2015,14(22):3635-3643
PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4+ and CD8+ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response. 相似文献