Selection of an Effective Indicator for Rapid Detection of Microorganisms Producing γ-Polyglutamic Acid and Its Biosynthesis Under Submerged Fermentation Conditions Using Bacillus methylotrophicus.

γ-Polyglutamic acid (γ-PGA) is a biosynthetic outcome of glutamic acid polymerization by microbes. In the current study, we have isolated Bacillus methylotrophicus on solid differential media containing methylene blue. This is the first report mentioning the use of methylene blue to distinguish the monomeric and polymeric form of glutamic acid in the liquid medium using UV-Vis spectrophotometer. Our method can simplify the analytical process of γ-PGA confirmation using the aforementioned studies. This screening protocol is sensitive to the detection of γ-PGA quantities as low as 3 µg/mL; thus, the potent producers can be effectively screened. Furthermore, we have carried out process optimization of the present strain for γ-PGA production wherein we could obtain 1.4-fold improvement in the yield with respect to utilization of carbon source and 2.6-fold increase with respect to nitrogen source under submerged fermentation at a shake flask level. We have shown an increase in γ-PGA titer from 1.5 to 36 g/L using mannitol, monosodium glutamate, peptone, and tween 20.

Pharmacophore Modeling, virtual and in vitro screening for acetylcholinesterase inhibitors and their effects on amyloid-ß self- assembly.

One of the most promising methods of unveiling the pharmacology of marketed drugs is to screen them against new biological targets. In an attempt to find inhibitors for acetylcholinesterase (AChE), the Drug Bank Database and natural alkaloids with other known medicinal values were screened through a four-point pharmacophore built in this study. The development of the pharmacophore was based on a structurally diverse set of reported AChE inhibitors and was validated using a separate set of known inhibitors. The developed pharmacophore indicated that the presence of one H-acceptor motif, one H-donor motif, one positively charged group and one aromatic ring is needed for AChE inhibition. Selected hits were further investigated by molecular docking and in vitro testing. The assays revealed that the majority of these compounds showed reasonable inhibition, indicating that the developed pharmacophore can indeed reliably screen molecules for potential AChE inhibitors. It appears that several commercially available marketed drugs have further potential as AChE inhibitors. To extend our study the same compounds have been tested in the fibrillogenesis inhibition of amyloidß (Aß) peptide to explore the possibility of their dual-function therapeutic activity in Alzheimer's disease.

Heteropoly acid-catalyzed microwave-assisted three-component aza-Diels-Alder cyclizations: diastereoselective synthesis of potential drug candidates for Alzheimer's disease.

A highly diastereoselective microwave-assisted three component synthesis of azabicyclo[2.2.2]octan-5-ones by a silicotungstic acid-catalyzed aza-Diels-Alder cyclization is described. The one-pot process involves the formation of the in situ generated Schiff base and its immediate cyclization with cyclohex-2-enone. The short reaction times, good yields and excellent diastereoselectivity make this annulation a practical and environmentally attractive method for the synthesis of the target compounds. Preliminary assays were carried out to determine the activity of the products in AChE as well as in amyloid ß fibrillogenesis inhibition.

Stability and conformation of the complexes of riboflavin with aromatic hydroxy compounds in an aqueous medium.

Overall equilibrium constants K' for the formation of molecular complexes of riboflavin with the conjugate forms of different aromatic hydroxy compounds are greater in magnitude than those involving the protonated forms of the hydroxy compounds. There is good agreement between the K(B) values determined by using absorption and emission methods. Based on the magnitude of K(B), it is possible to differentiate between the donor capacities of the hydroxy compounds in the charge transfer complexes with riboflavin. Molecular modeling studies indicate stacking interactions for all the systems in an aqueous medium.

Studies on the riboflavin-resorcinol interaction in an aqueous medium and its pH dependence.

The equilibrium constants, K', for the formation of the molecular association complex between riboflavin and resorcinol in the pH range 6-8 were found to be in the range 5-25 mol(-1)dm(3) by difference absorption spectroscopy. The equilibrium constants from emission spectroscopy were estimated to be in the range 38-55 mol(-1)dm(3) over the same pH range. Both sets of K' show a remarkable dependence on pH. The equilibrium constants K(A) and K(B) describing the interaction of riboflavin with neutral and ionic forms of resorcinol, respectively, obtained by resolving K', shows that K(B) is much greater than K(A). Molecular modeling studies suggest a stacked conformation of the two components in the complexed form. The interaction energies obtained from modeling studies also suggest a stronger interaction between the ionic form of resorcinol and riboflavin.