Sunil Misra

Evaluation of genotoxic effects of oral exposure to aluminum oxide nanomaterials in rat bone marrow.

Nanomaterials have novel properties and functions because of their small size. The unique nature of nanomaterials may be associated with potentially toxic effects. The aim of this study was to evaluate the in vivo genotoxicity of rats exposed with Aluminum oxide nanomaterials. Hence in the present study, the genotoxicity of Aluminum oxide nanomaterials (30 and 40 nm) and its bulk material was studied in bone marrow of female Wistar rats using chromosomal aberration and micronucleus assays. The rats were administered orally with the doses of 500, 1000 and 2000 mg/kg bw. Statistically significant genotoxicity was observed with Aluminum oxide 30 and 40 nm with micronucleus as well as chromosomal aberration assays. Significantly (p < 0.05 or p < 0.001) increased frequency of MN was observed with 1000 and 2000 mg/kg bw dose levels of Aluminum oxide 30 nm (9.4 +/- 1.87 and 15.2 +/- 2.3, respectively) and Aluminum oxide 40 nm (8.1 +/- 1.8 and 13.9 +/- 2.21, respectively) over control (2.5 +/- 0.7) at 30 h. Likewise, at 48 h sampling time a significant (p < 0.05 or p < 0.001) increase in frequency of MN was evident at 1000 and 2000 mg/kg bw dose levels of Aluminum oxide 30 nm (10.6 +/- 1.68 and 16.6 +/- 2.66, respectively) and Aluminum oxide 40 nm (9.0 +/- 1.38 and 14.7 +/- 1.68, respectively) compared to control (1.8 +/- 0.75). Significantly increased frequencies (p < 0.05 or p < 0.001) of chromosomal aberrations were observed with Aluminum oxide 30 nm (1000 and 2000 mg/kg bw) and Aluminum oxide 40 nm (2000 mg/kg bw) in comparison to control at 18 and 24 h. Further, since there is need for information on the toxicokinetics of nanomaterials, determination of these properties of the nanomaterials was carried out in different tissues, urine and feces using inductively coupled plasma mass spectrometry (ICP-MS). A significant size dependent accumulation of Aluminum oxide nanomaterials occurred in different tissues, urine and feces of rats as shown by ICP-MS data. The results of our study suggest that exposure to Aluminum oxide nanomaterials has the potential to cause genetic damage.

Biotransformation of ferulic acid to acetovanillone using Rhizopus oryzae

Microbial transformation of ferulic acid to acetovanillone was studied using growing cells of Rhizopus oryzae. Ferulic acid was added to the growing medium (0.5 g L−1) and incubated for 12 days. The progress of formation of metabolites was monitored by GC and GC-MS after extraction with ethyl acetate. The major metabolite was acetovanillone with minor metabolites formed, such as dihydroferulic acid, coniferyl alcohol and dihydroconiferyl alcohol. Traces of metabolites (≤1–3%), such as vanillin, vanillyl alcohol, vanillic acid and phenyl ethyl alcohol, were also produced. Formation of 4-vinyl guaiacol increased from day 1 (12.4%), reaching a maximum on day 4 (31.7%), and reducing to a minimum on day 12 (3.1%). The formation of acetovanillone increased only from day 2 onward, and reached a maximum (49.2%) on day 12. The optimum concentration of ferulic acid to be added into the medium was found to be only 0.5 g L−1, as any increase in concentration (0.75 and 1.0 g L−1) precipitated the precursor, resulting in no further degradation.

In vivo assessment of genotoxic effects of Annona squamosa seed extract in rats.

Widespread use of pesticides represents a potential risk to human and environmental health. Hence, biopesticides from plants are some of the future strategies for plant protection. In this regard, a seed extract of Annona squamosa was prepared and found to be a promising pesticide. In order to establish the inherent toxicity and non-target safety required for registration and marketing of pesticides, toxicological studies are conducted. The genotoxicity potential was evaluated in rats with 75, 150 and 300 mg/kg Annona squamosa by the comet assay in leucocytes, micronucleus and chromosomal aberration tests in bone marrow. We also studied the effects of 300 mg/kg of extract on lipid peroxidation, reduced glutathione level and glutathione S transferase activity in liver, lungs, brain, kidneys, heart and spleen of treated rats. The comet assay showed a statistically significant dose related increase in DNA migration. The micronucleus and chromosomal aberration tests revealed a significant induction in frequency of micronuclei and chromosomal aberrations at 150 and 300 mg/kg. Annona squamosa treatment significantly enhanced lipid peroxidation, decreased glutathione and glutathione S transferase levels revealing the oxidative stress condition. Our results warrant careful use of Annona squamosa seed extract as a biopesticide till more tests are carried out.

In Situ Strategy to Encapsulate Antibiotics in a Bioinspired CaCO3 Structure Enabling pH-Sensitive Drug Release Apt for Therapeutic and Imaging Applications

Herein we demonstrate a bioinspired method involving macromolecular assembly of anionic polypeptide with cationic peptide-oligomer that allows for in situ encapsulation of antibiotics like tetracycline in CaCO3 microstructure. In a single step one-pot process, the encapsulation of the drug occurs under desirable environmentally benign conditions resulting in drug loaded CaCO3 microspheres. While this tetracycline-loaded sample exhibits pH dependent in vitro drug-release profile and excellent antibacterial activity, the encapsulated drug or the dye-conjugated peptide emits fluorescence suitable for optical imaging and detection, thereby making it a multitasking material. The efficacy of tetracycline loaded calcium carbonate microspheres as pH dependent drug delivery vehicles is further substantiated by performing cell viability experiments using normal and cancer cell lines (in vitro). Interestingly, the pH-dependent drug release enables selective cytotoxicity toward cancer cell lines as compared to the normal cells, thus having the potential for further development of therapeutic applications.

Comparative Chemical Characterization of Pigmented and Less Pigmented Cell Walls of Alternaria tenuissima

Alternaria tenuissima, the parasitic fungus, was obtained from the pruned upper-cut surfaces of mulberry stems. This fungus contains dark pigment because of the presence of melanin in the cell wall. To obtain less-pigmented cell walls, this fungus was grown under dark condition. When the pigmented and less-pigmented cell walls were chemically analyzed, no differences were observed in amino-acid composition, hexoses, or pentoses. However, in pigmented cell walls, higher contents of melanin (2.6%) were found than in less-pigmented cell walls (0.3%). Interestingly, a significant difference was observed in the relative fatty-acid compositions between these two types of cell walls. Among the major fatty acids, there were increased concentrations of tetradecanoic acid (C14:0), hexadecanoic acid (C16:0), 9-hexadecenoic acid (C16: 1,Δ9), and 9-octadecanoic acid (C18:1,Δ9) and a concomitant decrease in 9,12-octadecadienoic acid (C18:2,Δ9,12) in less-pigmented compared with pigmented cell walls. This difference in fatty-acid composition may be related to the higher percentage of melanin in the pigmented than the less-pigmented cell walls. Lesser amounts of 9,12-octadecadienoic acid in less-pigmented cell walls may have been caused by the growth of the fungus under environmental stress conditions. An interesting observation was the presence in pigmented cell walls only of methyl-substituted fatty acids with carbon numbers C14 to C17, but their occurrence could not be ascertained in the present study.

Screening Strains of the Mulberry Silkworm, Bombyx mori, for Thermotolerance

Abstract A tropical climate prevails in most of the sericultural areas in India, where temperature increases during the summer lead to adverse effects on temperate bivoltine silkworm rearing and cause crop losses. Screening for thermotolerance in the silkworm, Bombyxmori L. (Lepidoptera: Bombycidae) is an essential prerequisite for the development of thermotolerant breeds/hybrids. In the current study, the aim was to identify potential bivoltine silkworm strains specific for tolerance to high temperature. The third day of fifth stage silkworm larvae of bivoltine strains were subjected to high temperature of 36 ± 1° C with RH of 50 ± 5 % for six hours (10:00–16:00) every day until spinning for three consecutive generations. Highly significant differences were found among all genetic traits of bivoltine silkworm strains in the treated groups. Three groups of silkworm resulted including susceptible, moderately tolerant, and tolerant by utilizing pupation rate or survival rate with thermal stress as the index for thermotolerance. Furthermore, based on the overall silkworm rearing performance of nine quantitative genetic traits such as larval weight, cocoon yield by number and weight, pupation, single cocoon and shell weight, shell ratio, filament length and denier, three bivoltine silkworm strains, BD2-S, SOF-BR and BO2 were developed as having the potential for thermotolerance. The data from the present study enhance knowledge for the development of thermo tolerant silkworm breeds/ hybrids and their effective commercial utilization in the sericulture industry.

Prioritization of malaria endemic zones using self-organizing maps in the Manipur state of India

Due to the availability of a huge amount of epidemiological and public health data that require analysis and interpretation by using appropriate mathematical tools to support the existing method to control the mosquito and mosquito-borne diseases in a more effective way, data-mining tools are used to make sense from the chaos. Using data-mining tools, one can develop predictive models, patterns, association rules, and clusters of diseases, which can help the decision-makers in controlling the diseases. This paper mainly focuses on the applications of data-mining tools that have been used for the first time to prioritize the malaria endemic regions in Manipur state by using Self Organizing Maps (SOM). The SOM results (in two-dimensional images called Kohonen maps) clearly show the visual classification of malaria endemic zones into high, medium and low in the different districts of Manipur, and will be discussed in the paper.

Antimicrobial efficacy of secondary metabolites from Glomerella cingulata

Fungi are known to produce a vast array of secondary metabolites that are gaining importance for their biotechnological applications. Early reports suggest that G. cingulata has the capability to transform many compounds by various enzymatic actions. Therefore, the focus of this study was to determine the antibacterial and antifungal activity of crude ethyl acetate extract of G. cingulata using agar cup bioassay method. Crude extract of G. cingulata exhibited remarkable antifungal activity against Rhizopus oryzae, Chrysoporium tropicum and Beauveria bassiana but no antifungal activity was found against Alternaria tenuissima and Aspergillus niger at any concentrations. The crude extract presented no antibacterial activity against Gram positive and Gram negative bacteria at any concentration.

Synthesis and biological evaluation of 5-fatty-acylamido-1, 3, 4-thiadiazole-2-thioglycosides

In the present study, the synthesis of 1, 3, 4-thiadiazole-based thioglycosides were accomplished in good yields with employing a convergent synthetic route. The starting material 5-amino-1, 3, 4-thiadiazole-2-thiol and followed by a series of 5-fatty-acylamido-1, 3, 4-thiadiazole-2-thiols (4a-4j) were synthesized with different fatty acid chlorides. The glycosylation of compounds 4a-4j were achieved with trichloroacetimidate methodology. Antimicrobial and cytotoxicity activities of title compounds were evaluated. Among the entire compounds lauric acid and myristic acid derivatives showed good and moderate antimicrobial activity. In case of cytotoxicity results of compounds 8a-8j and 9a-9j, the acetate protected short chain (C6:0, C8:0, C10:0) compounds and the free hydroxyl long chain saturated (C16:0, C18:0) and unsaturated (C18:1, C22:1) compounds exhibited good activity against different cancer cell lines. Further, the free hydroxyl compounds 9a, 9c-9j did not show any toxicity towards normal CHO-K1 cell line whereas acylated compounds 8a-8j exhibited toxicity.

Dehydrocostus lactone induces prominent apoptosis in kidney distal tubular epithelial cells and interstitial fibroblasts along with cell cycle arrest in ovarian epithelial cells

Dehydrocostus lactone (DHCL), a sesquiterpene lactone is well-known for its antiulcer, anti-hepatotoxic and anticancer activity. However, the studies concerning the safety/toxicity potential of DHCL toward the cells of normal origin remain unclear. The present study is aimed at investigating the toxicity potential of DHCL in renal distal tubular and interstitial fibroblast cell lines (MDCK and NRK-49F cells, respectively), and also in ovarian epithelial cell line (CHO cells). The MTT assay has predicted potential cytotoxic activity of DHCL against the cell line types with IC50 values of 0.99, 2.1 and 5.15??M, respectively. The prominent dose-dependent (IC30,50 & 70) increase in the percentage of cells at subG1 phase in all the cell lines revealed apoptosis induction, further establishing the cytotoxic effect of DHCL. The DHCL exposure (4?h) revealed the induction of ROS in both renal cell lines, which is responsible for apoptosis induction. The NRK-49F cells displayed dose-wise (IC30-70) increase in chromatin condensation and membranous phosphatidylserine translocation further confirming apoptotic cell death. Also, their increase in BAX/Bcl-2 ratio, mitochondrial membrane permeability and caspase-3/7 activity establishes mitochondrial mediated apoptosis. In case of CHO cells, the higher percentage of cells at G2/M phase and expression of Cyclin B1 at lower concentration of DHCL (?IC30), indicate mitotic arrest. The incidence of chromatid gaps and negligible micronuclei formation in treated cells (IC10-30) suggest that sub-lethal concentrations of DHCL exposure causes mitotic arrest in response to the damages by steady expression of Cyclin B1. Under in vitro condition, the study of DHCLs potential cytotoxic effect on both kidney cells and ovarian epithelial cells indicated the possibility of adverse effects on normal healthy cells as well. Hence, the study recommends in-depth investigations on DHCL usage concerning its safety in therapeutic applications.