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1.
Sacramento Doralice Rodrigues Coelho Rosalie Reed Rodrigues Wigg Márcia Dutra Toledo Luna Linhares Luiz Fernando de Matos dos Santos Marta Gonçalves Azevedo Soares Semêdo Luzia Teixeira de Ribeiro da Silva Antonio Jorge 《World journal of microbiology & biotechnology》2004,20(3):225-229
A promising producer of bioactive compounds isolated from a Brazilian tropical soil was tested for its range of antimicrobial
activities. Strain 606, classified as Streptomyces sp., could not be identified up to species level, suggesting a possible new taxon. The supernatant and 10 extracts and fractions,
obtained by extraction and chromatographic techniques, presented antimicrobial activity using antibiograms. The methanolic
fraction was highly active against pathogenic bacteria, phytopathogenic fungi and the human pathogenic yeast Candida albicans. It also possessed high antiviral activity inhibiting the propagation of an acyclovir-resistant herpes simplex virus type
1 strain on HEp-2 cells at non-cytotoxic concentration. The strong cytotoxic effect suggests an antitumour action.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
J Rivera J M Mullins K Furuichi C Isersky 《Journal of immunology (Baltimore, Md. : 1950)》1986,136(2):623-627
Rat basophilic leukemia (RBL) cells have distinct receptors for IgE and IgG. We assessed the endocytosis of chemically and immunochemically cross-linked mouse-IgG and its influence on the simultaneous endocytosis of IgE. We found that at 37 degrees C, aggregates of IgG and IgE were endocytosed at about the same rate with one-half of the maximal endocytosis occurring in 5 to 13 min, and the efficiency of endocytosis for both ligands ranging from 40 to 70%. We also found that endocytosis of cross-linked IgE and IgG occurred simultaneously and neither ligand significantly affected the rate or extent of endocytosis of the other. The cells accumulated the cross-linked IgG, and then released it to the extracellular environment, at a rate (less than 3%/hr) slower than the released endocytosed IgE (greater than 10%/hr). Using an assay that discriminates between unbound and receptor-bound oligomeric IgG, we found that oligomeric IgG is endocytosed with its receptor, and that the bulk of the ligand remains bound to its receptor for greater than 120 min after endocytosis. The differences in the rate of release of endocytosed IgG vs IgE suggests that the intracellular fate or pathway of these two oligomeric ligands may differ. 相似文献
3.
We evaluated in a rat model the effects of a homologous fibrin glue in reversing the effects of Adriamycin on adherence and take of skin grafts. A total of 40 male Fisher rats were used in the study. During the first phase of the experiment, the animals were assigned to either group I (N = 10) receiving normal saline or group II (N = 10) receiving 6 mg/kg Adriamycin by tail vein injection 24 hours before surgery. Skin grafts with and without fibrin glue were placed over wounds in the backs of the animals and adherence was measured at 24 and 48 hours. In the second phase (N = 20), the experiment was repeated, this time evaluating the total area of skin graft take at 7 days. Fibrin glue was found to increase adherence and take of skin grafts in all Adriamycin-treated animals. 相似文献
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Nitroso-aldicarb was tested for its ability to induce sister-chromatid exchanges (SCE) and cell-cycle delay in human peripheral blood lymphocytes in vitro. This derivative of aldicarb induced a dose-dependent increase in SCE values per cell. In addition, a slight decrease in the successive mitotic progression of cells in culture was observed. 相似文献
9.
Rogelio O. Arellano Fidel Ramón Amelia Rivera Guido A. Zampighi 《The Journal of membrane biology》1988,101(1):119-131
Summary Lateral axons from the abdominal nerve cord of cray-fish were internally perfused with the calcium receptor calmodulin (CaM) in solutions with low (pCa>7.0) or high (pCa 5.5) calcium concentrations and studied electrophysiologically and morphologically. Results from these experiments show that when the internal solution contains calcium-activated calmodulin (Ca2+-CaM) the junctional resistance between the axons increases from control values of about 60 to 500–600 k in 60 min. In contrast, axons perfused with calmodulin in low calcium solutions maintain their junctional resistance at control levels during the 60-min perfusion. Similar results are obtained when only one or both coupled axons are perfused.The morphological study shows that in the perfused axons the axoplasmic organelles are replaced or grossly perturbed by the perfusion solution up to the region of the synapses. Additionally, in axons perfused with Ca2+-CaM there are regions where the synaptic gap between the membranes decreases from a control 4–6 to 2–3 nm. Both electrophysiological and morphological results can be interpreted as indicating that calcium-activated calmodulin acts directly on the junctional channels to induce their closure. 相似文献
10.
Richard B. Marchase Vincent J. Kidd Angel A. Rivera Michael G. Humphreys-Beher 《Journal of cellular biochemistry》1988,36(4):453-465
Rat parotid gland acinar cells stimulated to divide by a chronic regimen of isoproterenol demonstrate a dramatic increase in the synthesis of the glycosyltransferase 4β-galactosyltransferase. A plasma membrane localization for much of the increase in 4β-galactosyltransferase was determined by density gradient membrane fractionation. Golgi-enriched fractions showed no increase in specific activity, while plasma membrane activity increased 40-fold. This selective increase at the cell surface was confirmed by immunofluorescence of intact, nonpermeabilized cells from treated glands, using a monospecific antibody prepared against the purified bovine milk transferase. In detergent-permeabilized cells staining of nontreated cells was seen only as groups of perinuclear vesicles, presumed to be Golgi apparatus. In isoproterenol-treated and permcabilized cells both presumptive Golgi and cell surface staining was apparent. Enzyme assays performed on intact cells established that the enzyme's active site was oriented to the exterior of the cells. The transferase could be detected as early as 3 hr after the primary challenge with isoproterenol. Pretrcatment of rats with cycloheximide prevented its appearance. 相似文献