A carbon source-dependent antimetabolite sensitivity test in Bacillus megaterium B71 for isolation of ethionine resistant mutants

Alteration of carbon sources significantly altered the analogue sensitivity of Bacillus megaterium B71. DL-Ethionine (ETN) was highly inhibitory with glucose, mannitol, sucrose, citrate, glycerol and arabinose. DL-Norleucine, L-homoserine and S(2'-aminoethyl)-L-cysteine were either highly inhibitory, slightly inhibitory or non-inhibitory depending on the carbon sources used. Maltose markedly overcame the inhibitory effect of ETN in liquid culture. Uninhibited growth was poor on citrate and arabinose when compared with other carbon sources. Six carbon sources showing comparable growth were used to determine minimum inhibitory concentrations (MIC) of the analogues. The MIC of ETN was highest (450 μg/ml) with maltose and lowest (4 μg/ml) with mannitol. ETN sensitivity was inversely related to the endogenous L-methionine pool size, and was relatively low with mannitol which was used to isolate ETN resistant mutants of B. megaterium B71. The best mutant BUE-118 produced 435 μg/ml of L-methionine.     

New Strategies of LIBS-Based Validation of Glycemic Elements for Diabetes Management

Antidiabetic efficacy of medicinal plant cannot be ignored in order to develop drugs without toxicity and side effects. Trace elements present in plant material is responsible for their medicinal nature and hence it is necessary to know the major and minor constituents of the plant material. Laser-induced breakdown spectroscopy (LIBS) is a very efficient and powerful analytical tool to monitor the elements present in sample. The present study deals with the LIBS-based validation of glycemic elements present in Withania coagulans and Cajanus cajan medicinal herbs. The decreasing blood glucose level and improving glucose tolerance test significantly showed that the higher content of Mg and Ca in W. coagulans in comparison to C. cajan is responsible for its significant role in diabetes management, whereas the concentration of other elements are nearly the same in both extracts.     

Validation of an Optimized ELISA for Quantitative Assessment of Epstein-Barr Virus Antibodies from Dried Blood Spots

Our objective was to validate a commercially available ELISA to measure antibody titers against Epstein-Barr virus (EBV) in dried blood spots (DBS) to replace a previously validated assay for DBS that is no longer available. We evaluated the precision, reliability, and stability of the assay for the measurement of EBV antibodies in matched plasma, fingerprick DBS, and venous blood DBS samples from 208 individuals. Effects of hematocrit and DBS sample matrix on EBV antibody determination were also investigated, and the cutoff for seropositivity in DBS was determined. A conversion equation was derived to enable comparison of results generated using this method with the former DBS method. There was a high correlation between plasma and DBS EBV antibody titers (R² = 0.93) with very little bias (?0.07 based on Bland-Altman analysis). The assay showed good linearity and did not appear to be affected by the DBS matrix, and physiological hematocrit levels had no effect on assay performance. There was reasonable agreement between DBS EBV titer estimates obtained using this assay and the previously validated assay (R² = 0.72). The commercially available ELISA assay for EBV antibody titers that we validated for use with DBS will facilitate continued investigation of EBV antibody titers in DBS.     

Modifying effect of iron on lead-induced clastogenicity in mouse bone marrow cells

Essential trace elements such as iron (Fe) are known to interact with nonessential metals like lead (Pb), influencing its metabolism. Ferric chloride and lead nitrate were administered intraperitoneally to Swiss albino miceMus musculus singly and successively, with or without a time gap of 1 h, to study the degree of protection, if any, afforded by iron against the clastogenic effects induced by Pb in bone marrow cells. A decrease in the frequency of lead-induced chromosomal aberrations was observed when Fe was given together with or prior to Pb administration.     

High activity xylanase from Aspergillus sydowii MG49 during growth on jute stalk lignocellulose

Aspergillus sydowil MG49 produced 33.0 U mg^-1 of extracellular xylanase activity when grown in liquid state fermeniation (LSF) with 1% ground jute stalk as the sole carbon source compared to 56.0 U mg^-1 when pure xylan was used. Optimum time-course and pH for maximum enzyme production were 144 h and 4.0 respectively. The culture filtrate was devoid of any cellulase and β-xylosidase activity. The xylanase exhibited optimum activity at 60°C and pH 5.5. Partially-fermented jute stalk could be recycled at least twice for xylanase production, exhibiting 25.8 and 17.4 U mg^-1 activity in two later consecutive cycles respectively.     

Lichens as a potential natural source of bioactive compounds: a review

Biological activity of material whether known in folk medicine or observed in planned screening program has been the starting point in the drug research. The general pattern is the isolation of active principles, elucidation their structures, followed by attempts for modulation of its activity potential by chemical modification. Lichens are valuable plant resources and are used as medicine, food, fodder, perfume, spice, dyes and for miscellaneous purposes throughout the world. Lichens are well known for the diversity of secondary metabolites that they produce. Compounds isolated from various lichen species have been reported to display diverse biological activities. Here we review the medicinal efficacy of lichen substances, which intends to explore the pharmaceutical potential of lichen substances.