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101.
102.
Iu N Rusakov V M Bondareva V S Karasev B N Le?bush R S Barkan M N Pertseva 《Biokhimii?a (Moscow, Russia)》1991,56(4):718-726
An insulin-like substance (ILS) was isolated from the visceral organs of the bivalve mollusc Anodonta cygnea by chromatography on a sulfocationite CU-23 and purified by reverse phase liquid chromatography. ILS was shown to be made up to several fractions with Mr ranging from 9 to 20 kDa which have identical amino acid composition but different hydrophobicity and N-terminal amino acids. It was supposed that the heterogeneity of ILS fractions is due to its genetical or posttranslational polymorphism. ILS has a low (0.02%) affinity for the mammalian insulin receptor and a low immune affinity for mammalian insulin and possesses a mitogenic activity which is commensurate with that of the epidermal growth factor. The data obtained suggest that Anodonta cygnea ILS represents a separate branch of a relatively ancient family of insulin-like hormones and growth factors responsible for metabolism and proliferation of invertebrate tissues. 相似文献
103.
A rapid and efficient bactometer method was developed for screening biocides against sulfate-reducing bacteria. The method is based on impedance microbiology principles and uses double-layer API (American Petroleum Institute) agar medium supplemented with 0.1% sodium thioglycolate as a reducing agent. Compared to the conventional API procedure, which requires 28 days, the present technique takes only 1 day to obtain test results. Excellent linear correlation (r=–0.98) was found between the impedance detection time and log initial cell concentration. The results of the bactometer test were comparable to that of the API bottle test. 相似文献
104.
The bacterial oxidation of D-glucose to D-gluconic and keto-D-gluconic acids has been studied. Different approaches to pH-control have been checked. It is demonstrated, that the microbial growth is independent on pH-control. However, the rate of keto-gluconate production is too sensitive to the strategy of pH-maintenance and particularly to the neutralizing agent. The general opinion for the essential importance of addition of calcium ions for keto-gluconate formation is confirmed. The interpretation of the obtained experimental data by means of a simple mathematical model shows that the apparent lag-phase in keto-gluconate production is probably due to the necessity of accumulation of biomass as a biocatalyst and gluconic acids as a substrate. 相似文献
105.
A patient was referred to the Charles Clifford Dental Hospital with a grey metallic pigmentation of the hard palate. Conventional histopathological examination was inconclusive, suggesting the presence of either an ephelis (freckle) of pigmentation resulting from a stainless steel upper denture. Material from the pathological specimen was dewaxed and reembedded in Spurr's resin. Examination in the TEM revealed electron dense deposits in the cytoplasm of macrophages. Energy dispersive X-ray microanalysis demonstrated that these inclusions contained iron. The results suggested that the iron was in a form similar to haemosiderin and had arisen from the steel denture. 相似文献
106.
Molecular cloning and expression of the human melanocyte stimulating hormone receptor cDNA. 总被引:19,自引:0,他引:19
Melanocytes and melanoma cells are known to possess receptors for melanocyte stimulating hormone (MSH). A cDNA clone, designated 11D, has been isolated from human melanoma cells and encodes a MSH receptor. The cloned cDNA encodes a 317 amino acid protein with transmembrane topography characteristics of a G-protein-coupled receptor, but it does not show striking similarity to already published sequences of other G-protein-coupled receptors. When 11D cDNA is expressed in COS-7 cells, it binds an 125I-labelled MSH analogue (NDP-MSH) in a specific manner. The bound ligand could be displaced by melanotropic peptides, alpha-MSH, beta-MSH, gamma-MSH and ACTH (adrenocorticotropic hormone), but not by the non-melanotropic peptide, beta-endorphin. This is the first report of the cloning of the receptor gene of the melanotropin receptor family. 相似文献
107.
The ability of native alpha- and non-coagulating gamma-thrombin to catalyze the hydrolysis of nonspecific high molecular weight substrates was studied using chymotrypsinogen and the oxidized insulin B-chain as substrates. The effect of thrombin on chymotrypsinogen was estimated by the appearance of caseinolytic activity measured by the increase in the number of terminal NH2-groups in the 2,4,6-trinitrobenzol sulfonic acid reaction. The same reaction was used to study the hydrolysis of insulin by thrombin. It was found that the destruction of the additional center necessary for fibrinogen proteolysis during the alpha-thrombin conversion to the gamma-form did not affect the enzyme ability to hydrolyze nonspecific protein substrates. It was assumed that the low efficiency of non-physiological high molecular weight substrate hydrolysis by thrombin is due to the lack of specific remote interactions in the regulatory site outside the enzyme active center. 相似文献
108.
The ability of the initiation factor eIF-2 in skeletal muscle extracts to form ternary initiation complexes ([Met-tRNA(f).eIF-2.GDP]) is decreased by either starvation or diabetes. These conditions also impair the ability of muscle extracts to dissociate [eIF-2.GDP], suggesting inhibition of the guanine nucleotide exchange reaction essential for eIF-2 recycling. We could not, however, detect any change in the phosphorylation state of the alpha subunit of eIF-2. This suggests that eIF-2 activity may be regulated in this system by a mechanism not involving its phosphorylation. 相似文献
109.
The proteins of parasporal crystals of 9 strains of entomopathogenic bacteria of the Bacillus thuringiensis group of different H-serotypes were studied by different methods. Electrophoresis showed that crystals from the bacteria of 1, 3, 4, 5, 8, and 10 serotypes contained 1-2 proteins with a molecular weight of 130-145 kD and an additional fraction with a molecular weight of 55-120 kD. Double-radial immunodiffusion revealed that the crystals of all the serotypes studied are immunologically related. The proteins contained at least 3 types of antigens that can be detected either separately or all together when being tested with different antisera. The ELISA technique showed that the crystal proteins homologous with respect of antigens gave, as a rule, similar titration results. 相似文献
110.
Miguel Angel Pujana Monica Gratacós Jordi Corral Isabel Banchs Aurora Sánchez David Genís Carlos Cervera Víctor Volpini X. Estivill 《Human genetics》1997,101(1):18-21
Genetic anticipation – increasing severity and a decrease in the age of onset with successive generations of a pedigree –
is clearly present in autosomal dominant cerebellar ataxia (ADCA). Anticipation is correlated with expansion of the CAG/CTG
repeat sequence to sizes above those in the normal range through the generations of a pedigree. Genetic heterogeneity has
been demonstrated for ADCA, with four cloned genes (SCA1, SCA2, SCA3/MJD, and SCA6) and three mapped loci (SCA4, SCA5 and
SCA7). Another related dominant ataxia, dentatorubral-pallidoluysian atrophy (DRPLA), presents anticipation with CAG/CTG repeat
expansions. We had previously analysed ADCA patients who had not shown repeat expansions in cloned genes for CAG/CTG repeat
expansions by the repeat expansion detection method (RED) and had detected expansions of between 48 and 88 units in 17 unrelated
familial cases. We present here an analysis of 13 genes and expressed sequence tags (ESTs) containing 10 or more CAG/ CTG
repeat sequences selected from public databases in the 17 unrelated ADCA patients. Of the 13 selected genes and ESTs, 9 were
found to be polymorphic with heterozygosities ranging between 0.09 and 0.80 and 2 to 17 alleles. In ADCA patients none of
the loci showed expansions above the normal range of the CAG/CTG repeat sequences, excluding them as the mutation causing
ADCA.
Received: 28 May 1997 / Accepted: 30 June 1997 相似文献