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排序方式: 共有110条查询结果,搜索用时 31 毫秒
71.
T. N. Ivshina S. D. Artamonova V. P. Ivshin F. F. Sharnina 《Applied Biochemistry and Microbiology》2009,45(3):313-318
A four-stage procedure for the isolation of the ChGC from the biomass of natural fungi—the honey mushroom (Armillariella mellea) and the yellow morel (Morchella esculenta), belonging to the classes Basidiomycetes and Ascomycetes, respectively, has been developed. The isolation procedure included deproteinization (2% NaOH + 0.1% sodium stearate, 83–85°C, 2 h), demineralization (1% HCl, 55–60°C, 2 h), depigmentation (5% H2O2 in ammonia (30–35°C, 4 h)), and deglucanization (2% NaOH, 83–85°C, 2 h). The original raw material and the chitin-containing materials were characterized on the basis of results of Fourier transform infrared spectroscopy, X-ray analysis, and pyrolytic gas chromatography using crustacean chitin as a reference compound. The content of chitin in the final products was 70% for A. mellea and 50% for M. esculenta. The possibility of obtaining chitin-containing materials with the required properties by selecting the fungal species and treatment conditions (the succession and repetition of certain stages) is demonstrated. 相似文献
72.
We present a new in vitro system for characterizing the binding and mobility of enhanced green fluorescent protein (EGFP)-labeled nuclear proteins by fluorescence recovery after photobleaching in digitonin-permeabilized cells. This assay reveals that SRm160, a splicing coactivator and component of the exon junction complex (EJC) involved in RNA export, has an adenosine triphosphate (ATP)-dependent mobility. Endogenous SRm160, lacking the EGFP moiety, could also be released from sites at splicing speckled domains by an ATP-dependent mechanism. A second EJC protein, RNPS1, also has an ATP-dependent mobility, but SRm300, a protein that binds to SRm160 and participates with it in RNA splicing, remains immobile after ATP supplementation. This finding suggests that SRm160-containing RNA export, but not splicing, complexes have an ATP-dependent mobility. We propose that RNA export complexes have an ATP-regulated mechanism for release from binding sites at splicing speckled domains. In vitro fluorescence recovery after photobleaching is a powerful tool for identifying cofactors required for nuclear binding and mobility. 相似文献
73.
Ivshina IB Grishko VV Nogovitsina EM Kukina TP Tolstikov GA 《Prikladnaia biokhimiia i mikrobiologiia》2005,41(6):626-633
The ability of pure cultures of Rhodococcus actinobacteria from the Ural specialized collection of alkanotrophic microorganisms (World Federation for Culture Collections accession number 768; http://www.ecology.psu.ru/iegmcol) to convert beta-sitosterol (BSS) and its 3beta-acylated derivatives was studied. Rhodococcus strains with pronounced cholesterol oxidase activity, capable of converting BSS to stigmat-4-ene-3-one in the reaction of cooxidation with n-hexadecane, were selected. The dependence of the activity of cholesterol oxidase of rhodococci on the length of the acyl group in BSS esters was studied. Conditions under which Rhodococcus cells convert BSS to 17beta-hydroxyandrost-4-ene-3-one (testosterone), commonly used in pharmacology, were determined. 相似文献
74.
Crustacean and cheliceratan hemocyanins (oxygen-transport proteins) and
insect hexamerins (storage proteins) are homologous gene products, although
the latter do not bind oxygen and do not possess the copper- binding
histidines present in the hemocyanins. An alignment of 19 amino acid
sequences of hemocyanin subunits and insect hexamerins was made, based on
the conservation of elements of secondary structure observed in X-ray
structures of two hemocyanin subunits. The alignment was analyzed using
parsimony and neighbor-joining methods. Results provide strong indications
for grouping together the sequences of the 2 crustacean hemocyanin
subunits, the 5 cheliceratan hemocyanin subunits, and the 12 insect
hexamerins. Within the insect clade, four methionine- rich proteins, four
arylphorins, and two juvenile hormone-suppressible proteins from
Lepidoptera, as well as two dipteran proteins, form four separate groups.
In the absence of an outgroup sequence, it is not possible to present
information about the ancestral state from which these proteins are
derived. Although this family of proteins clearly consists of homologous
gene products, there remain striking differences in gene organization and
site of biosynthesis of the proteins within the cell. Because studies on
18S and 12S rRNA sequences indicate a rather close relationship between
insects and crustaceans, we propose that hemocyanin is the ancestral
arthropod protein and that insect hexamerins lost their copper-binding
capability after divergence of the insects from the crustaceans.
相似文献
75.
76.
Oil desorption from mineral and organic materials using biosurfactant complexes produced by Rhodococcus species 总被引:2,自引:0,他引:2
I.B. Ivshina M.S. Kuyukina J.C. Philp N. Christofi 《World journal of microbiology & biotechnology》1998,14(5):711-717
Rhodococcus strains from the culture collection at the Institute of Ecology and Genetics of Microorganisms, Perm, Russia were examined for biosurfactant production during growth on n-alkanes and the ability to remove oil associated with contaminated sands and oil shale cuttings. Members of the genus, particularly R. ruber, were shown to produce low toxicity surfactants effective in removing oil from surfaces. The extent of desorption was inversely related to the concentration of high molecular weight hydrocarbons, namely asphaltenes and resins. In addition, crude surfactant complexes enhanced the degradation of crude oil, in the short term, when added to contaminated agricultural soil during bioremediation studies utilizing biopiling technology. 相似文献
77.
Multiple haplotypes from each of three nuclear loci were isolated and
sequenced from geographic populations of the American oyster, Crassostrea
virginica. In tests of alternative phylogeographic hypotheses for this
species, nuclear gene genealogies constructed for these haplotypes were
compared to one another, to a mitochondrial gene tree, and to patterns of
allele frequency variation in nuclear restriction site polymorphisms
(RFLPs) and allozymes. Oyster populations from the Atlantic versus the Gulf
of Mexico are not reciprocally monophyletic in any of the nuclear gene
trees, despite considerable genetic variation and despite large allele
frequency differences previously reported in several other genetic assays.
If these populations were separated vicariantly in the past, either
insufficient time has elapsed for neutral lineage sorting to have achieved
monophyly at most nuclear loci, or balancing selection may have inhibited
lineage extinction, or secondary gene flow may have moved haplotypes
between regions. These and other possibilities are examined in light of
available genetic evidence, and it is concluded that no simple explanation
can account for the great variety of population genetic patterns across
loci displayed by American oysters. Regardless of the source of this
heterogeneity, this study provides an empirical demonstration that
different sequences of DNA within the same organismal pedigree can have
quite different phylogeographic histories.
相似文献
78.
The aim of this experiment was to evaluate the effects of an intracerebroventricular (icv) injection of prostaglandin E1 (PGE1) on the sympathetic activation and the thermogenic changes in rats with acute lesions of the ventromedial hypothalamus (VMH). Four groups of six Sprague-Dawley male rats were anesthetized with ethyl-urethane. The firing rate of the sympathetic nerves innervating the interscapular brown adipose tissue (IBAT) and the colonic and IBAT temperatures were monitored both before and after one of the following treatments: 1) VMH lesion plus icv injection of PGE1 (500 ng); 2) VMH lesion plus icv injection of saline; 3) sham lesion plus icv injection of PGE1; and 4) sham lesion plus icv injection of saline. PGE1 induced an increase in the firing rate of IBAT nerves and the colonic and IBAT temperatures. These effects were reduced by VMH lesion. The findings indicate that acute lesions of the VMH reduce the effects of PGE1 and seem to suggest a possible role played by the VMH in the control of the sympathetic activation and the thermogenic changes during PGE1 hyperthermia. 相似文献
79.
TD Smith KP Bhatnagar CJ Bonar KL Shimp MP Mooney MI Siegel 《American journal of physical anthropology》2003,122(3):301-301
80.
This paper looked at the leaf architecture characteristics of Vachellia tortilis to determine if either there is or not an effect of the tropic line on plants. Vachellia tortilis leaves were sampled along a national road (N1) in Limpopo province. Sampling points were set 10 km apart away from the Tropic of Capricon in opposite directions. Leaf morphology revealed that leaves of V. tortilis are bipinnately compound with alternate arrangement. The venation pattern of the pinnules was eucamptodromus and brochidodromous with imperfect reticulation. Areoles were imperfect and pentagonal or irregular in shape. 相似文献