Alterations in rat gut bacteria and intestinal epithelial cells following experimental exposure of antimicrobials

The intestinal bacteria are known to play a significant role in intestinal homoeostasis and the mucosal immune system. In vitro interactions of Ampicillin (0.5-2.0 microg mL(-1)), Amphotericin-B (25-200 microg mL(-1)) and Ciprofloxacin (50-500 ng mL(-1)) with Escherichia coli, Pseudomonas sp. (Gram-negative), Lactobacillus sp., Staphylococcus sp. (Gram-positive), total mixed population of gut bacteria and intestinal epithelial cells were studied. In vitro exposure of Ciprofloxacin showed significant dose-dependent inhibition throughout the growth phase in bacteria. Similar patterns of concentration-dependent changes in membrane transport enzymes and structural constituents, dehydrogenase activity associated with respiratory and energy-producing processes and esterase activity test linked to the general heterotrophic activity of the cell were observed in both bacteria and epithelial cells. The antibiotic effects were in the order of Amphotericin-B相似文献   

Commercial and ethnic use of lichens in India

The diversity of Indian lichen flora has undergone a considerable decline in the last five decades. Among the various anthropogenic activities, overexploitation and selective removal of economically important lichens have become major threats to the lichen flora of the country. Commercial samples of lichens collected from different states of India were studied for their source and commercial use. Among samples offered for sale, 38 different lichen species were identified. The western Himalayas proved to be the main area for lichen collection, while some lichen species also come from the central and Western Ghats. Local traders coordinate the lichen collection and then sell the material to traders in the foothills, and from there it is processed and distributed to other parts of the country and abroad. Because lichens belonging to the families Parmeliaceae and Physciaceae are the ones most exploited commercially, they are recommended for inclusion in the CITES list.     

Anaerobic biodegradation of diesel fuel-contaminated wastewater in a fluidized bed reactor

Diesel fuel spills have a major impact on the quality of groundwater. In this work, the performance of an Anaerobic Fluidized Bed Reactor (AFBR) treating synthetic wastewater is experimentally evaluated. The wastewater comprises tap water containing 100, 200 and 300 mg/L of diesel fuel and nutrients. Granular, inert, activated carbon particles are employed to provide support for biomass inside the reactor where diesel fuel is the sole source of carbon for anaerobic microorganisms. For different rates of organic loading, the AFBR performance is evaluated in terms of the removal of diesel fuel as well as chemical oxygen demand (COD) from wastewater. For the aforementioned diesel fuel concentrations and a wastewater flow rate of 1,200 L/day, the COD removal ranges between 61.9 and 84.1%. The concentration of diesel fuel in the effluent is less than 50 mg/L, and meets the Level II groundwater standards of the MUST guidelines of Alberta.     

Identification of the major phosphorylation site in Bcl-xL induced by microtubule inhibitors and analysis of its functional significance

Vinblastine and other microtubule inhibitors used as antimitotic cancer drugs characteristically promote the phosphorylation of the key anti-apoptotic protein, Bcl-xL. However, putative sites of phosphorylation have been inferred based on potential recognition by JNK, and no direct biochemical analysis has been performed. In this study we used protein purification and mass spectrometry to identify Ser-62 as a single major site in vivo. Site-directed mutagenesis confirmed Ser-62 to be the site of Bcl-xL phosphorylation induced by several microtubule inhibitors tested. Vinblastine-treated cells overexpressing a Ser-62 --> Ala mutant showed highly significantly reduced apoptosis compared with cells expressing wild-type Bcl-xL. Co-immunoprecipitation revealed that phosphorylation caused wild-type Bcl-xL to release bound Bax, whereas phospho-defective Bcl-xL retained the ability to bind Bax. In contrast, phospho-mimic (Ser-62 --> Asp) Bcl-xL exhibited a reduced capacity to bind Bax. Functional tests were performed by transiently co-transfecting Bax in the context of different Bcl-xL mutants. Co-expression of wild-type or phospho-defective Bcl-xL counteracted the adverse effects of Bax expression on cell viability, whereas phospho-mimic Bcl-xL failed to provide the same level of protection against Bax. These studies suggest that Bcl-xL phosphorylation induced by microtubule inhibitors plays a key pro-apoptotic role at least in part by disabling the ability of Bcl-xL to bind Bax.     

Preparation of representative homogenates of biological tissues: effect of salt on protein extraction.

A technique for the preparation of representative homogenates of tissues is described. For most soft tissues and biological fluids (liver, kidney, semen) more than 80% of protein was recovered after homogenization in isotonic buffer. With tissues that are harder to homogenize, such as heart, spleen, and skeletal muscle, however, only approximately 40-50% of protein was extracted in this medium. Inclusion of salt or salt plus detergent during the homogenization increased recovery of the protein to levels close to those recorded with soft tissues. The increase represented a true recovery and was not an artifact induced by salt/detergent. This situation is parallel to previously reported results for lipid-rich biological tissues.     

Structures of the novel α-glucosyl linked diterpene glycosides from Stevia rebaudiana

From the commercial extract of the leaves of Stevia rebaudiana, two new minor diterpene glycosides having α-glucosyl linkage were isolated besides the known steviol glycosides including stevioside, steviolbioside, rebaudiosides A–F, rubusoside and dulcoside A. The structures of the two compounds were identified as 13-[(2-O-(3-α-O-d-glucopyranosyl)-β-d-glucopyranosyl-3-O-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid β-d-glucopyranosyl ester (1), and 13-[(2-O-β-d-glucopyranosyl-3-O-(4-O-α-d-glucopyranosyl)-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid β-d-glucopyranosyl ester (2), on the basis of extensive NMR and MS spectral data as well as chemical studies.     

Effects of Brassmosteroids on Growth, Nodulation, Phytohormone Content and Nitrogenase Activity in French Bean Under Water Stress

Effect of pre-treatments of 1 and 5 M epibrassinolide or homobrassinolide prior to water stress induction on changes in root nodulation and contents of endogenous abscisic acid (ABA) and cytokinin trans-zeatin riboside (ZR), and nitrogenase activity was investigated in the nodulated roots of Phaseolus vulgaris L. cv. Arka Suvidha. Brassinosteroids in the unstressed plants increased root nodulation, ZR content and nitrogenase activity, and also ameliorated their stress-induced decline in the nodulated roots. The ABA contents in the nodules of control or stressed plants were not altered by brassinosteroids treatment. There was an increase in pod yield by brassinosteroids treatment (5 M) in the irrigated control as well as stressed plants without influencing pod number or pod length. Among the brassinosteroids, epibrassinolide was relatively more effective.     

The treatment of isolated genera

Problems presented by genera, or small groups of genera, which have been given family rank are reviewed, and the genera are divided into a number of categories according to the closeness of their affinity to other genera or families. Satellite genera that stand in close relation to families should be united with them. Binary families, that have been divided into two (or more) related families, should be re–united. Families connected by linking genera, should, logically, be united but practical considerations usually prevent this. Clusters of diverse but more or less distantly related genera present unusual problems, being treated either as several, often monogeneric families or as a loosely structured family. Truly isolated genera must be given family and often ordinal rank.     

Intrinsic perturbing ability of alkanols in lipid bilayers

The proportionality constant between the equipotency concentrations of a series of solutes and the fraction of a solute in the membrane phase is directly related to the solute to lipid mol ratio. Experimental measurements of partition coefficient and of several alkanol-induced effects show that the solute/lipid mol ratlos for a series of alkanols are not constant at their equipotency concentrations. The deviations in the solute/lipid ratios are similar in the various systems, and these deviations seem to depend primarily upon the chain length and branching in alkanols. It is suggested that such intrinsic differences in the perturbing ability of alcohols arise from a specificity of interaction between alkanols and lipid bilayer. We have correlated partition coefficients (in n-octanol, in egg phosphatidylcholine liposomes, and in dipalmitoyl phosphatidylcholine liposomes) for thirteen alkanols to the equipotency concentrations for their ability to modify the order-disorder thermotropic transition in dipalmitoyl phosphatidylcholine, ability to stimulate the hydrolysis of phosphatidylcholine in a bilayer by bee venom phospholipase A₂, and for the activation of the galactoside transport system in Escherichia coli. Significant correlation is found between equipotency concentrations for perturbing the order-disorder transition, the activation of phospholipase A₂-catalyzed hydrolysis and the activation of galactoside transport system.