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21.
S.P. Pathak J.W. Bhattacherjee N. Kalra S. Chandra 《Journal of applied microbiology》1988,65(4):347-352
The seasonal distribution of Aeromonas hydrophila in water and recovery rate from live river fish was investigated. The highest isolation rates of A. hydrophila occurred in water during the late winter followed by a progressive decline in density during the summer and monsoon seasons. The organism was recovered from fish throughout the period from which it was concluded that they form a reservoir which is unrelated to their density in water. The enterotoxigenicity of some environmental strains was tested in suckling mice and rabbit ileal loop. 相似文献
22.
The mothers of experimental neonates were administered excess bilirubin for a month, and the neonates were suffering from hyperbilirubinemia. The studies were conducted on the effect of excess bilirubin and metalloporphyrins on plasma membrane and mitochondrial membrane. We have isolated, separated, and estimated phospholipids, and also assayed the activity of phospholipase A2 from whole liver and mitochondrial and microsomal fractions. Excess of bilirubin administration decreased the total phospholipid level and inhibited the phospholipase A2 activity. Cr-PP (chromium protoporphyrin) induces the phospholipase A2 activity which is inhibited by simultaneous bilirubin administration. However, Zn-PP (zinc protoporphyrin) and Mn-PP (manganese protoporphyrin) showed a reverse pattern. 相似文献
23.
A. Seetharama Acharya Rajendra Prasad Roy Bhuvaneshwari Dorai 《Journal of Protein Chemistry》1991,10(3):345-358
The relative roles of the two structural aspects of nonenzymic glycation sites of hemoglobin A, namely the ease with which the amino groups could form the aldimine adducts and the propensity of the microenvironments of the respective aldimines to facilitate the Amadori rearrangement, in dictating the site selectivity of nonenzymic glycation with aldotriose has been investigated. The chemical reactivity of the amino groups of hemoglobin A forin vitro reductive glycation with aldotriose is distinct from that in the nonreductive mode. The reactivity of amino groups of hemoglobin A toward reductive glycation (i.e., propensity for aldimine formation) decreases in the order Val-1(), Val-1(), Lys-66(), Lys-61(), and Lys-16(). The overall reactivity of hemoglobin A toward nonreductive glycation decreased in the order Lys-16(), Val-1(), Lys-66(), Lys-82(), Lys-61(), and Val-1(). Since the aldimine is the common intermediate for both the reductive and nonreductive modification, the differential selectivity of protein for the two modes of glycation is clearly a reflection of the propensity of the microenvironments of nonenzymic glycation sites to facilitate the isomerization reaction (i.e., Amadori rearrangement). A semiquantitative estimate of this propensity of the microenvironment of the nonenzymic glycation sites has been obtained by comparing the nonreductive (nonenzymic) and reductive modification at individual glycation sites. The microenvironment of Lys-16() is very efficient in facilitating the rearrangement and the relative efficiency decreases in the order Lys-16(), Lys-82(), Lys-66(), Lys-61(), Val-1(), and Val-1(). The propensity of the microenvironment of Lys-16() to facilitate the Amadori rearrangement of the aldimine is about three orders of magnitude higher than that of Val-1() and is about 50 times higher than that of Val-1(). The extent of nonenzymic glycation at the individual sites is modulated by various factors, such as thepH, concentration of aldotriose, and the concentration of the protein. The nucleophiles—such as tris, glycine ethyl ester, and amino guanidine—inhibit the glycation by trapping the aldotriose. The nonenzymic glycation inhibitory power of nucleophile is directly related to its propensity to form aldimine. Thus, the extent of inhibition of nonenzymic glycation at a given site by a nucleophile directly reflects the relative role ofpK
a
of the site in dictating the glycation at that site. The nonenzymic glycation of an amino group of a protein is an additive/synergestic consequence of the propensity of the site to form aldimine adducts on one hand, and the propensity of its microenvironment to facilitate the isomerization of the aldimines to ketoamines on the other. The isomerization potential of microenvironment plays the dominant role in dictating the site specificity of the nonenzymic glycation of proteins. 相似文献
24.
Fifty bronchial washing specimens from 36 patients with acquired immune deficiency syndrome (AIDS) were retrospectively reviewed to assess the sensitivity of the various special stains used to diagnose Pneumocystis carinii. In 76% of the cases, the Diff-Quik stain was positive; it was the easiest and most rapid of the special stains used. The sensitivity was increased to 92%, 96% and 100%, respectively, by also doing cresyl echt violet, Grocott's Gomori methenamine silver and both the cresyl violet and Grocott stains in addition to the Diff-Quik stain. We conclude that the Diff-Quik stain is a fairly reliable and rapid screening procedure for making the diagnosis of Pneumocystis infection in bronchial washings from AIDS patients. The routine Papanicolaou stain gave less sensitive results in the smears of the washing specimens, but does give a markedly improved yield in bronchoalveolar lavage specimens. 相似文献
25.
Rajendra G. Mehta Leonard J. Schiff Steven J. Moore Ann Marie Buckley Marcia I. Dawson 《In vitro cellular & developmental biology. Plant》1986,22(3):164-168
Summary The mechanism of action of retinoid in reversing keratinization in hamster trachea is yet unknown. The purpose of this study
was to determine if cellular retinoic acid binding protein (CRABP) is present in tracheal epithelium following incubation
in serum-free, vitamin A-deficient culture medium for 10 days, and if the effectiveness of a retinoid in reversing keratinization
in organ culture is correlated with its ability to compete for CRABP sites. The cytosol prepared from tracheal cultures contained
CRABP at a concentration of 2.61 pmoles per mg protein. Of the four retinoids with carboxyl end group selected for the study,
two of the biological active retinoids competed for the CRABP sites. However, no correlation was observed between the biological
activity of the inactive retinoids and their ability to associate with the CRABP sites. These results indicate that even though
the action of retinoid may be mediated by retinoid binding protein, it cannot be used as a sole predicator of retinoid response
in hamster trachea.
This investigation was supported by Contract N01-CP-31012 and U. S. P. H. Grants CA30512 and CA32428, which were awarded by
the Division of Cancer Etiology, National Cancer Institute, DHHS.
Editor's Statement Tracheal organ cultures provide a useful model for the study of epithelial differentiation and carcinogenesis.
Much attention has been given to the action of retinoids in this process. Mehta et al. demonstrate a lack of correlation between
biological activity and specific cytosolic binding of members of this class of compounds, pointing out the need for a more
complete biochemical understanding of the mechanism of action and active forms of retinoids in this and other systems in vivo
and in vitro. David W. Barnes 相似文献
26.
Incidence of actinomycetes infection in women using intrauterine contraceptive devices 总被引:1,自引:0,他引:1
Pancervicovaginal smears taken from 350 women using an intrauterine contraceptive device (IUD) were screened for the presence of actinomycetes organisms. Of the 12 cases in which actinomycetes-like organisms were seen in Papanicolaou-stained smears, the presence of actinomycetes organisms was confirmed by immunofluorescence in 10 cases. The prevalence of actinomycetes infection was thus 2.8% (10 of 350 cases) in the IUD users. Eight (4.3%) of 173 symptomatic subjects had actinomycetes infections. Two of the positive cases were asymptomatic. Eight of the ten patients with confirmed actinomycetes infection were using the Cu T device while two were wearing the Lippes Loop IUD. Seven of the ten patients had been using an IUD for more than two years. The time of insertion of the IUD (postpuerperal, postmenstrual or after medical termination of pregnancy) did not show any correlation with the presence of actinomycetes infection. Actinomyces israelii was responsible for the infection in eight cases while Arachnia propionica was seen in two cases. The organisms could not be grown in culture. 相似文献
27.
John J. Langone Chandra Das Robin Mainwaring William T. Shearer 《Molecular and cellular biochemistry》1985,65(2):159-170
Summary Protein A of Staphylococcus aureus is an Fc receptor for IgG that has been used as a therapeutic reagent to treat cancer in humans and experimental animals. We used ultracentrifugation combined with analysis of isolated fractions by radioimmunoprecipitation and competitive radioimmunoassay with chicken antibodies that bind free protein A or protein A in complexes but do bind free immunoglobulin reagents to localize and characterize the types of complexes formed with different molar ratios of 125I-protein A and human 131I-IgG alone or in serum, and 1311-Fc fragments. This approach offers a distinct advantage over direct counting of radioactivity in the fractions because resolution of complexes and free reagents is much improved. With excess 131I-IgG or 1311-Fc, all the 125I-protein A is present only in complexes that contained 4 molecules of immunoglobulin reagent and 2 molecules of protein A (4:2 complexes), whereas with excess 125I-protein A the stoichiometry of the complexes was 1:1. We have also shown the preformed 4:2 and 1:1 complexes will interconvert in the presence of added excess protein A or IgG, respectively, and that fresh IgG will exchange with IgG or Fc in preformed complexes. Because protein A has been found to elute from an immobilized reagent used in serotherapy of human cancer and is present in a large excess of IgG, the 4:2 complexes may play an active role in the tumoricidal or toxic reactions observed.Abbreviations SpA
protein A of Staphyloccus aureus
- VBS
EDTA gel, 0.0055 M veronal buffered saline containing 0.01 M EDTA and 0.1% gelatin, pH 7.4
- PBS
0.01 M phosphate buffered saline, pH 7.4 相似文献
28.
S Chandra W C Harris G H Morrison 《The journal of histochemistry and cytochemistry》1984,32(11):1224-1230
The ion microscope, based on secondary ion mass spectrometry, has been used to demonstrate the distribution of calcium in the root tip cells of two plant species, Allium cepa and Vicia faba. Interphase nuclei showed higher intensities of calcium than cytoplasm, while nucleoli exhibited higher calcium intensities than the rest of the nucleoplasm. The chromosomes showed high intensities of calcium at all stages of mitosis. Calcium was also detected in the cell plate and phragmoplast region of dividing cells. It appears that during prophase calcium concentrates in the condensing chromosomes, and during telophase it is transferred to nucleoli. These observations suggest that chromosomes may serve as a reservoir of calcium during mitosis. 相似文献
29.
30.
Sequence homology between human alpha 1-antichymotrypsin, alpha 1-antitrypsin, and antithrombin III 总被引:15,自引:0,他引:15
alpha 1-Antichymotrypsin mRNA was isolated by specific polysome immunoprecipitation from turpentine-treated baboon liver. The highly enriched mRNA was used for synthesis and cloning of the corresponding cDNA. Baboon alpha 1-antichymotrypsin cDNA clones were identified by hybrid-selected translation, and the insert DNA fragment from one of the putative clones was used as a probe to screen a human liver cDNA library comprised of 40 000 independent transformants. One of the human cDNA clones was unambiguously identified to contain alpha 1-antichymotrypsin DNA sequences by comparison of its 5'-terminal nucleotide sequence with the N-terminal amino acid sequence of the protein. This cDNA clone, designated phACT235, contains 1524 base pairs of human DNA, which was sequenced in its entirety. The inserted DNA codes for a 25 amino acid signal peptide sequence and the entire mature alpha 1-antichymotrypsin of 408 amino acid residues. Comparison of the amino acid sequence of alpha 1-antichymotrypsin with that of the human alpha 1-antitrypsin has revealed a homology level similar to that between chymotrypsin and trypsin. 相似文献