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Various numerical methods were used to estimate the coordination of taxa of gram-negative aerobic and facultative anaerobic organoheterotrophic and chemolithotrophic bacteria. Stable phena were found to be formed by cultures belonging to the families Rhizobiaceae, Halobacteriaceae, Enterobacteriaceae, Nitrobacteriaceae (except the genus Nitrobacter), and Methylomonadaceae (except the genus Methylococcus). The unstable position was found in the genera Thermus, Zoogloea, Xanthomonas, Sulfolobus, Methylococcus, Alcaligenes, Brucella, and Acetobacter. The greatest scatter among the objects being analysed was detected among genera belonging to the family Pseudomonadaceae. The taxonomic position of these genera must be defined more precisely. The family Methylomonadaceae is related to such physiologically unique groups of microorganisms as nitrifying, sulfate-reducing, extreme thermophilic and halophilic forms. All in all, the data reported in this work show that numerical analysis can be used to specify the classification structure of bacteria. In a number of cases, the results are consistent with those changes which are performed in the Bergey Manual 9 using logical analysis (for instance, concerning the position of the genera Gluconobacter, Acetobacter, Beijerinckia, and Derxia). 相似文献
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Iu R Malashenko V A Romanovskaia I G Sokolov T P Kryshtab E S Liudvichenko 《Ukrainski? biokhimicheski? zhurnal》1980,52(2):159-163
The biological role of exogenous carbon dioxide during substrate assimilation with a various degree of reductivity is evaluated. The investigation of metabolic pathways of carbon dioxide incorporation into the metabolic processes of methaneoxidizing bacteria shows that the HCO3- ion assimilation is catalyzed by phosphoenolpyruvate carboxylase and in certain strains also by the key enzyme of autotrophic pathway of the carbon dioxide assimilation, ribulose-1,5-diphosphate carboxylase. The theoretical calculations and experimental studies indicate that exogenous carbon dioxide is a necessary participant of the metabolic processes of methane or methanol assimilation. It is also an acceptor of the excess electrons of these compounds. It is the degree of reductivity of the substrate metabolized that determines the activity of the exogenous carbon dioxide fixation by microorganisms. The carbon dioxide fixation by heterotrophic microorganisms must be considered, therefore, as a process which is mostly due to the elementary composition of the source of carbon under conversion. 相似文献
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The pink-pigmented facultative methylotrophic bacteria (PPFMB) of the genus Methylobacterium are indespensible inhabitants of the plant phyllosphere. Using maize Zea mays as a model, the ways of plant colonization by PPFMB and some properties of the latter that might be beneficial to plants were studied. A marked strain, Methylobacterium mesophilicum APR-8 (pULB113), was generated to facilitate the detection of the methylotrophic bacteria inoculated into the soil or applied to the maize leaves. Colonization of maize leaves by M. mesophilicum APR-8 (pULB113) occurred only after the bacteria were applied onto the leaf surface. In this case, the number of PPFMB cells on inoculated leaves increased with plant growth. During seed germination, no colonization of maize leaves with M. mesophilicum cells occurred immediately from the soil inoculated with the marked strain. Thus, under natural conditions, colonization of plant leaves with PPFMB seems to occur via soil particle transfer to the leaves by air. PPFMB monocultures were not antagonistic to phytopathogenic bacteria. However, mixed cultures of epiphytic bacteria containing Methylobacterium mesophilicum or M. extorquens did exhibit an antagonistic effect against the phytopathogenic bacteria studied (Xanthomonas camprestris, Pseudomonas syringae, Erwinia carotovora, Clavibacter michiganense, and Agrobacterium tumifaciens). Neither epiphytic and soil strains of Methylobacterium extorquens, M. organophillum, M. mesophilicum, and M. fujisawaense catalyzed ice nucleation. Hence, they cause no frost injury to plants. Thus, the results indicate that the strains of the genus Methylobacterium can protect plants against adverse environmental factors. 相似文献
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Rokitko PV Romanovskaia VA Malashenko IuR Chernaia NA Gushcha NI Mikheev AN 《Mikrobiologiia》2003,72(6):854-861
The drying of soil samples reduced the abundance (especially of predominant species) and the diversity of bacteria isolated from these samples, making easier the isolation of rare bacterial species. Some bacterial species that were minor before soil drying became dominant in dried soil samples. In general, soil drying allowed the diversity of soil bacteria to be determined more adequately. The bacteria that were isolated from dried soil samples turned out to be resistant to gamma radiation (with LD90 = 2.8-4.6 kGy) and desiccation. It is concluded that soil drying may serve as a model for the action of stress factors on natural bacterial populations. The hypothesis that periodic desiccation was the primary cause of formation of bacterial radioresistance in nature is discussed. 相似文献
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Role of Toll-like receptors and defensins in antimicrobial protection of urogenital tract in females
Gankovskaia OA Koval'chuk LV Gankovskaia LV Lavrov VF Romanovskaia VV Kartashov DD Fenzeleva VA 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》2008,(1):46-50
Levels of expression of hBD-1 gene (beta-defensin 1) and Toll-like receptors (TLR1, TLR2, TLR6) in cells of cervical mucosa in healthy nonpregnant and healthy pregnant women as well as in pregnant women with urogenital infection was measured by developed RT-PCR systems. During normal pregnancy compared with nonpregnant women, increase of TLRs genes expression which was correlated with increase of hBD-1 gene expression was observed. During urogenital infection in pregnant women compared with healthy pregnant, 10- fold and 50-fold increase of TLR1 and TLR2 genes expression respectively was associated with 2.5-fold decrease of hBD-1 gene expression in cervical mucosa. In group of women with untrauterine infection more marked increase of TLRs genes expression was observed. Thus significant changes (TLRs, antimicrobial peptides, cytokines etc.) in cells of cervical mucosa can be used as prognostic criteria for development of intrauterine infection. 相似文献
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Aruna Kasoju M Lakshmi Narasu Charuvaka Muvva Bathula VV SubbaRao 《Bioinformation》2012,8(14):684-686
Aflatoxins are polyketide-derived secondary metabolites produced by Aspergillus spp. The toxic effects of aflatoxins have adverse
consequences for human health and agricultural economics. The aflR gene, a regulatory gene for aflatoxin biosynthesis, encodes a
protein containing a zinc-finger DNA-binding motif. AFLR-Protein three-dimensional model was generated using Robetta server.
The modeled AFLR-Protein was further optimization and validation using Rampage. In the simulations, we monitored the
backbone atoms and the C-α-helix of the modeled protein. The low RMSD and the simulation time indicate that, as expected, the
3D structural model of AFLR-protein represents a stable folding conformation. This study paves the way for generating computer
molecular models for proteins whose crystal structures are not available and which would aid in detailed molecular mechanism of
inhibition of aflatoxin. 相似文献