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2.
Biology and Fertility of Soils - The survival and cast production of the tropical endogeic earthworm Pontoscolex corethrurus and the changes in chemical and physical characteristics induced by gut...  相似文献   
3.
Antiserum to a synthetic peptide recognizes the HTLV-III envelope glycoprotein   总被引：28，自引：0，他引：28  
In a study performed to determine which regions of the human T-cell lymphotrophic virus type III (HTLV-III) may represent vaccine candidates to prevent the acquired immune deficiency syndrome (AIDS), a synthetic peptide corresponding to amino acid sequence 735 to 752 of the precursor envelope glycoprotein of HTLV-III was used to immunize rabbits. The resulting rabbit antiserum to the synthetic peptide specifically recognized the precursor envelope glycoprotein (gp160) of HTLV-III. Human sera positive for antibody to HTLV-III reacted with this peptide. These findings indicate that synthetic peptides can be used to induce an immune response directed against a native envelope glycoprotein epitope of HTLV-III. The data are discussed in terms of using synthetic peptides to identify antigenic determinants involved in the induction of protective immunity and possibly as vaccine candidates against the etiologic agent of AIDS.  相似文献   
4.
The aims of the present study were to determine (i) the profiles of phylogroup and (ii) the antimicrobial susceptibility of pathogenic Escherichia coli strains isolated from calves, and of Salmonella spp. strains isolated from calves and pigs in Minas Gerais State, Brazil. Sixty-one pathogenic E. coli strains and Salmonella spp. (n?=?24) strains isolated from fecal samples of calves and Salmonella spp. (n?=?39) strains previously isolated from fecal samples of growing/finishing pigs were tested. The minimum inhibitory concentration (MIC) using the agar dilution method was determined for nalidixic acid, amikacin, amoxicillin, ampicillin, cefoxitin, norfloxacin, gentamicin, tetracycline, and trimethoprim-sulfamethoxazole. All E. coli isolates were susceptible to amikacin. Tetracycline was the antimicrobial that presented the higher frequency of resistance among E. coli strains, followed by ampicillin, trimethoprim-sulfamethoxazole, amoxicillin, nalidixic acid, norfloxacin, gentamicin, and cefoxitin. E. coli (n?=?61) strains isolated from calves belonged to different phylogroup namely, phylogroup A (n?=?26), phylogroup B1 (n?=?31), phylogroup E (n?=?3), and phylogroup F (n?=?1). Phylogroups B2, C, and D were not identified among the E. coli in the present study. All Salmonella spp. (n?=?24) strains isolated from fecal samples of calves were susceptible to amikacin, amoxicillin, ampicillin, norfloxacin, gentamicin, tetracycline, and trimethoprim-sulfamethoxazole. Resistance to nalidixic acid and cefoxitin was detected in 16.66 and 8.33 % of the Salmonella spp. strains, respectively. Among the Salmonella spp. (n?=?39) strains isolated from fecal samples of pigs, the higher frequency of resistance was observed to tetracycline, followed by amoxicillin, gentamicin, ampicillin, trimethoprim-sulfamethoxazole, nalidixic acid, cefoxitin, and norfloxacin. All strains were susceptible to amikacin. Forty-eight (78.68 %) of the E. coli strains were classified as multidrug-resistant, whereas among Salmonella spp. strains, the percentage of multidrug resistance was 57.14 %, being all multidrug-resistant strains isolated from pigs (92.30 %). The results from the present study indicate a high frequency of antimicrobial resistance among pathogenic E. coli strains isolated from calves and Salmonella spp. strains isolated from pigs and a high rate of susceptibility to most antimicrobials tested among Salmonella spp. strains isolated from calves. Our study highlights the presence of multidrug-resistant strains of E. coli and Salmonella spp. isolated from food-producing animals in Minas Gerais, Brazil.  相似文献   
5.
This review discusses the isolation, structural elucidation, and biological activities of halogenated indole alkaloids obtained from marine invertebrates. Meridianins and related compounds (variolins, psammopemmins, and aplicyanins), as well as aplysinopsins and leptoclinidamines, are focused on. A compilation of the 13C-NMR spectral data of these selected natural indole alkaloids is also provided.  相似文献   
6.
The essential oil composition and genetic variability of six commercial cultivars of thyme (Thymus vulgaris L.), a Mediterranean medicinal and aromatic plant, were analyzed by GC-MS and randomly amplified polymorphic DNA (RAPD), respectively. All evaluated cultivars belong to the thymol chemotype, with differences in the concentrations of thymol, gamma-terpinene, p-cymene, and other minor components. The comparison of the oil components concentration by multivariate analysis allowed separation of the cultivars into two groups. All of the cultivars exhibited characteristic RAPD patterns that allowed their identification. On the basis of the RAPD patterns, the cultivars could be divided into two clusters, which coincides with results obtained by oil GS-MS analysis, with a correlation coefficient of -0.779.  相似文献   
7.
Baccharis dracunculifolia (Asteraceae), the most important plant source of the Brazilian green propolis (GPE), displayed in vitro activity against Leishmania donovani, with an IC50 value of 45 µg/mL, while GPE presented an IC50 value of 49 µg/mL. Among the isolated compounds of B. dracunculifolia, ursolic acid, and hautriwaic acid lactone showed IC50 values of 3.7 µg/mL and 7.0 µg/mL, respectively. Uvaol, acacetin, and ermanin displayed moderate antileishmanial activity. Regarding the antiplasmodial assay against Plasmodium falciparum, BdE and GPE gave similar IC50 values (about 20 µg/mL), while Hautriwaic acid lactone led to an IC50 value of 0.8 µg/mL (D6 clone).  相似文献   
8.
The objective of this study was to investigate the development of the enteric, hepatic and muscle tissues in goat kids fed with lyophilized bovine colostrum in the transition period of passive immunity to early active immunity. At 0, 7 and 14 h of life, 15 male newborns received 5% of their body weight of lyophilized bovine colostrum and 14 male newborns received goat colostrum, both with 55 mg/ml of IgG. Samples of the duodenum, jejunum, ileum, liver and muscle were collected at 18, 36 and 96 h of life to quantify total protein, DNA and RNA contents. In the jejunum and ileum, the highest levels of total protein and higher protein/RNA ratio were observed at 18 h (p < 0.05). There were no differences in DNA contents in any intestinal segment (p > 0.05). At 96 h, maximum levels of RNA were observed in the jejunum and ileum (p < 0.05) and higher RNA/DNA ratio in the three intestinal segments (p < 0.05), showing increased ability to synthesize intracellular RNA and proteins. The LBC group showed higher protein content and higher protein/DNA and protein/RNA ratios in the jejunum, a higher DNA content in the liver (p < 0.05) and a higher protein/RNA ratio in the muscle tissue (p < 0.05). In the muscle, higher protein and DNA levels were also found at 96 h (p < 0.05). Indicators of cellular activity suggest greater absorption of proteins from lyophilized bovine colostrum and increased cell maturity in the enteric and muscle tissues in the first hours of goat kids' life.  相似文献   
9.
Consumption of a second meal of colostrum with high quality could contribute to the intestinal epithelium development, especially if there is poor supply of colostrum just after birth. The effect of a second colostrum meal was evaluated on histomorphometry of the intestinal mucosa of newborn Holstein calves fed with high‐ and low‐quality first colostrum. Seventy‐two calves were fed with a first colostrum meal with high (HFM, close to 100 mg/ml) or low (LFM, close to 30 mg/ml) IgG concentration. At 12 hr of life, three treatments of second colostrum feeding were applied to the calves either fed high or low first colostrum: calves fed with low (LOW—close to 30 mg/ml) or high (HIGH—close to 100 mg/ml) IgG concentration; and colostrum enriched with lyophilized bovine colostrum with high IgG concentration (ENRICHED—higher than 120 mg/ml), resulting in six groups. Intestinal samples were collected after 24 and 72 hr of life. In the distal jejunum and ileum, LOW showed higher villus height than ENRICHED (p < .05). In the distal jejunum, greater villus perimeter was observed in the LOW compared to ENRICHED at 24 hr (p < .05). In ileum, LFM showed higher villus perimeter compared to HFM (p < .05). LOW showed the highest villus height‐to‐crypt depth ratio in the medium and distal jejunum and ileum, p < .05. ENRICHED and HFM showed decreased muscle layer thickness in the proximal and distal jejunum respectively (p < .05). The results reveal that the high concentration of total solids, crude protein, IgG and IGF‐I of colostrum with high quality worsened the absorptive area, but may have stimulated the activity of cell division in intestinal crypts. Considering the present results, bovine colostrum enriched with lyophilized bovine colostrum stimulates intestinal epithelium renewal of Holstein calves in the first days of life.  相似文献   
10.
Ascidians of the genus Aplidium are recognized as an important source of chemical diversity and bioactive natural products. Among the compounds produced by this genus are non-nitrogenous metabolites, mainly prenylated quinones and hydroquinones. This review discusses the isolation, structural elucidation, and biological activities of quinones, hydroquinones, rossinones, longithorones, longithorols, floresolides, scabellones, conicaquinones, aplidinones, thiaplidiaquinones, and conithiaquinones. A compilation of the 13C-NMR spectral data of these compounds is also presented.  相似文献   
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