Host-specific plant signal and G-protein activator, mastoparan, trigger differentiation of zoospores of the phytopathogenic oomycete Aphanomyces cochlioides

We found that the gradient of a host-specific attractant, cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone) isolated from the roots of spinach triggered encystment followed by germination of zoospores of Aphanomyces cochlioidesat a concentration less than micromolar order. This compound did not affect the growth and reproduction of this phytopathogen up to 10^–6 M concentration in the culture medium. We also observed that mastoparan, an activator of heterotrimeric G-protein could inhibit the motility of zoospores and then strikingly effect encystment followed by 60–80% germination of cysts. Concomitant application of cochliophilin A and mastoparan showed stronger encystment followed by 100% germination of cysts. In addition, we have observed that chemicals interfering with phospholipase C activity (neomycin) and Ca²⁺ influx/release (EGTA and loperamide) suppress cochliophilin A or mastoparan induced encystment and germination. These results suggest that G-protein mediated signal transduction mechanism may be involved in the differentiation of the A. cochlioides zoospores. This is the first report on the differentiation of oomycete zoospores initiated by a host-specific plant signal or a G-protein activator.     

Kinetics of beta-glucosidase production by Saccharomyces cerevisiae recombinants harboring heterologous bgl genes

The maximum productivity of -glucosidase by Saccharomyces cerevisiaerecombinants under the control of GALI promoter was 100 IU l^–1 h^–1. The highest productivity of -glucosidase by a S. cerevisiae recombinant was 16-fold more than that supported by Cellulomonas biazotea. The recombinants also co-produced ethanol from cellobiose: maximum product yield and productivity were 0.5 and 1.1 g ethanol g^–1 cellobiose and g ethanol l^–1 h^–1, respectively.     

Improving wheat flour hydrolysis by an enzyme mixture from solid state fungal fermentation

In traditional cereal-based industrial processes, component separation is often incomplete resulting in a residue of mixed macromolecules including largely starch, protein, phytic acid and many others. The development of a viable cereal-based biorefinery would involve effective bioconversion of cereal components for the production of a nutrient-complete fermentation feedstock. Simultaneous starch and protein hydrolysis represents an effective approach to the production of platform chemicals from wheat. Solid state fermentations of wheat pieces and waste bread by Aspergillus oryzae and Aspergillus awamori have been combined in this study to enhance starch and protein hydrolysis. Kinetic studies confirmed that the proteolytic enzymes from A. oryzae introduced no negative effect on the stability of the amylolytic enzymes from A. awamori under the optimal conditions for starch hydrolysis. When applied to hydrolyse wheat flour, the enzyme solution from A. awamori converted nearly all of the starch into glucose and 23% of the total nitrogen (TN) into free amino nitrogen (FAN). Under the same reaction conditions the enzyme solution from A. oryzae hydrolysed 38% of the protein but only 18.5% of the starch. A mixture of the two enzyme solutions hydrolysed 34.1% of the protein, a 1.5-fold increase from that achieved by the enzyme solution from A. awamori, while maintaining a near completion of starch hydrolysis.     

Synthesis and biological evaluation of prodigiosene conjugates of porphyrin,estrone and 4-hydroxytamoxifen

To generate the first series of prodigiosene conjugates, the tripyrrolic skeleton was appended to estrone, tamoxifen and porphyrin frameworks by way of ester linkers and various hydrocarbon chain lengths. The ability of the conjugates to inhibit various types of cancer cells was evaluated in vitro. The porphyrin conjugates did not exhibit significant activity. The estrone conjugates exhibited modest activity, for the most part. However, significantly greater growth inhibition activity against certain breast, colon, lung, leukemia, melanoma and prostate cell lines was noted. This unusual effect for this first generation model class of compound warrants further investigation and comparison to cases where estrogens are linked to prodigiosenes via connection points that do not feature in estrogen receptor binding. The 4-hydroxytamoxifen conjugates exhibit nanomolar range activity against the MCF-7 breast cancer cell line, paving the way to expand the scope and connectivity of prodigiosene–tamoxifen conjugates.     

Identification of new benzamide inhibitor against α-subunit of tryptophan synthase from Mycobacterium tuberculosis through structure-based virtual screening,anti-tuberculosis activity and molecular dynamics simulations

Multi-drug-resistant tuberculosis and extensively drug-resistant tuberculosis has emerged as global health threat, causing millions of deaths worldwide. Identification of new drug candidates for tuberculosis (TB) by targeting novel and less explored protein targets will be invaluable for antituberculosis drug discovery. We performed structure-based virtual screening of eMolecules database against a homology model of relatively unexplored protein target: the α-subunit of tryptophan synthase (α-TRPS) from Mycobacterium tuberculosis essential for bacterial survival. Based on physiochemical properties analysis and molecular docking, the seven candidate compounds were selected and evaluated through whole cell-based activity against the H37Rv strain of M. tuberculosis. A new Benzamide inhibitor against α-subunit of tryptophan synthase (α-TRPS) from M. tuberculosis has been identified causing 100% growth inhibition at 25 μg/ml and visible bactericidal activity at 6 μg/ml. This benzamide inhibitor displayed a good predicted binding score (?48.24 kcal/mol) with the α-TRPS binding pocket and has logP value (2.95) comparable to Rifampicin. Further refinement of docking results and evaluation of inhibitor-protein complex stability were investigated through Molecular dynamic (MD) simulations studies. Following MD simulations, Root mean square deviation, Root mean square fluctuation and secondary structure analysis confirmed that protein did not unfold and ligand stayed inside the active pocket of protein during the explored time scale. This identified benzamide inhibitor against the α-subunit of TRPS from M. tuberculosis could be considered as candidate for drug discovery against TB and will be further evaluated for enzyme-based inhibition in future studies.