Effect of tetracycline family of antibiotics on actin aggregation, resulting in the formation of Hirano bodies responsible for neuropathological disorders.

Actin, an ATPase superfamily protein, regulates some vital biological functions like cell locomotion, cytokinesis, synaptic plasticity and cell signaling in higher eukaryotes, and is dependent on the dynamics of actin polymerization process. Impaired regulation of actin polymerization has been implicated in the formation and deposition of rod-like paracrystalline structures called as Hirano bodies in neuronal cells of patients suffering from Alzheimer's disease, Pick's disease, Guam amyotrophic lateral sclerosis and parkinsonism-dementia complex. Aggregation of actin forming amorphous deposition in the brain cells is also associated with chronic alcoholism and aging of the neurons. In the current article, we propose the breaking of the highly amorphous and dysregulated actin aggregates using generic compounds like tetracycline, oxytetracycline, doxycycline and minocycline which are used as antibiotics against tuberculosis and infection caused due to various Gram-negative bacteria. We have investigated the effect and affinity of binding of these four compounds to that of actin aggregates using 90° light scattering, size exclusion chromatography, dynamic light scattering, circular dichroism, scanning electron microscopy, transmission electron microscopy imaging and kinetic analysis. The isothermal calorimetric measurements showed that the binding constant for the cycline family molecules used in this study range from 9.8 E4 M-1 to 1.3 E4 M-1. To understand the in vivo effect, we also studied the effect of these drugs on Saccharomyces cerevisiae Δend3 mutant cells. Our data suggest that these generic compounds can plausibly be used for the treatment of various neurodegenerative diseases occurring due to Hirano body formation in brain cells.Communicated by Ramaswamy H. Sarma.

Proteomic and metabolomic approach to rationalize the differential mosquito larvicidal toxicity in Bacillus sp. isolated from the mid-gut of Culex quinquefasciatus mosquito larvae.

From the distinct wild locations of the Mumbai (India), dead Culex mosquito larvae were collected. The mid-gut micro-flora of these dead mosquito larvae was isolated on three different media that were selective for only the Gram-positive bacteria. These bacteria were tested against the third instar stage of Culex quinquefasciatus larvae, cultured in the laboratory, for their larvicidal activity. After performing the toxicity assay four times in duplicates, the average statistical values showed four bacteria exhibiting differential toxicities. Identification of these strains was done by 16S rRNA sequencing and their respective surface morphologies were studied by scanning electron microscopy (SEM). The differential toxicities of the four identified Bacillus strains were rationalized by performing differential proteomics and metabolomics approach using LC-MS and these results were analyzed against customized mosquito larvicidal toxin database which was further compared with the in silico p-BLAST data of that respective Bacillus sp. from the NCBI database. The presence and significance of the various mosquitocidal toxins in the identified Bacillus sp. are elucidated. The present study also attempted to identify new bacterial species exhibiting mosquitocidal toxicities that have not been reported earlier.

Enterococcus durans with mosquito larvicidal toxicity against Culex quinquefasciatus, elucidated using a Proteomic and Metabolomic approach.

Various bacteria from the Bacillus species have been used as pesticides against mosquito larvae for more than a decade. The prolonged use of these bacterial species by little alteration within their genome, using various permutations and combinations of mosquito-cidal toxins, has proven unsuccessful in controlling the mosquito population. In our current study we report Enterococcus sp. to be exhibiting similar kind of mosquito-cidal toxins alike those which are present in the mainly used Bacillus strains. Three Enterococcus species were isolated on a rich media selective for gram- positive bacteria from the mid-gut of dead mosquito larvae which were collected from the wild locations within and around the city of Mumbai, India. Their surface morphologies were studied by Scanning Electron Microscopy (SEM) and their identity was confirmed using the standard 16S rRNA sequencing method. Upon performing several repetitive toxicity assays of these three strains on the laboratory cultured third instar stage of Culex quinquefasciatus larvae, showed differential toxicities from a minimum of 20% (LC50: 59.6 CFU/ml), intermediate 35% (LC50: 48.4 CFU/ml) and a maximum of 60% (LC50: 35.7 CFU/ml). To justify the data in all the three similar strains of Enterococcus durans, we followed the differential proteomics using LCMS 6540 UHD Accurate Mass QTOF and differential metabolomics approach using both LCMS 6540 UHD Accurate Mass QTOF and 1H-NMR. The presence and significance of the obtained toxins were studied to elucidate the plausible reason for showing differential toxicities. This work helped in identifying Enterococcus durans as a new, potential and alternative strain to the Bacillus species in terms of mosquito larvicidal toxicity against Culex quinquefasciatus.

In Silico Design, Synthesis and Bioactivity of N-(2, 4-Dinitrophenyl)-3-oxo- 3-phenyl-N-(aryl) Phenyl Propanamide Derivatives as Breast Cancer Inhibitors.

BACKGROUND: Breast cancer is a systemic disease which has challenged physicians worldwide as it is the most predominant cancer in women often leading to fatality. One of the types of treatment is chemotherapy which includes targeted oral or intravenous cancer-killing drugs. Treatment options are often limited to surgery and/or chemotherapy. OBJECTIVE: The discovery and design of new small molecule estrogen inhibitors is necessitated in order to circumvent the problem of drug-induced resistance in chemotherapy resulting in disease relapse. Chemoinformatics facilitates the design, selection and synthesis of new drug candidates for breast cancer by providing efficient in silico techniques for prediction of favourable ADMET properties, and structural descriptors to profile druggability of a compound. METHOD: Several molecules selected from docking studies were synthesized and evaluated for their biological activities on the MCF-7 (human breast cancer) cell line. RESULTS: These estrogen inhibitors displayed good inhibitory activity with high selectivity and hence can be further progressed as drug candidates effective against breast cancer. CONCLUSION: It is for the first time that N-(2, 4-dinitrophenyl)-3-oxo-3-phenyl-N-(aryl) phenylpropanamide derivatives were reported to be biological active as potential breast cancer inhibitors.