Although the application of the concept of a threshold to risk assessment is widespread, there remains little experimental evidence for the existence of thresholds for genotoxic compounds, other than aneugens. The clastogenicity of topoisomerase inhibitors is believed to result from the transient stabilization of the topoisomerase enzyme with DNA during the catalytic cycle. This leads to the formation of a stabilized cleavage complex, which, in turn, may result in the formation of a DNA strand break. This indirect mechanism of clastogenicity is the basis for the concept of threshold for this class of drug. Using micronucleus induction in L5178Y mouse lymphoma cells as a genotoxic end-point, a three pronged approach was used to examine whether the concept of a threshold for clastogenicity could be demonstrated for topoisomerase type II inhibitors in vitro. This involved (i) the study of mechanism (TARDIS assay), (ii) hypothesis testing versus estimation (i.e. scoring up to 10,000 cells/treatment at concentrations immediately above and below the NOEL for micronucleus induction) and (iii) statistical modelling of the concentration-response curves for micronucleus induction. Several topoisomerase type II inhibitors were investigated with varying clastogenic potencies (etoposide = doxorubicin < genistein < ciprofloxacin). Pragmatic thresholds for clastogenicity in L5178Y cells were defined at 0.00236 microg/ml for etoposide, 0.00151 microg/ml for doxorubicin, 1 microg/ml for genistein and 50 microg/ml for ciprofloxacin. In addition, it was demonstrated that etoposide-induced clastogenicity was concentration and time dependent. These results, along with mechanistic data showing that all of the compounds induced concentration-dependent increases in the formation of topoisomerase II stabilized cleavage complexes, provide a weight of evidence to support a threshold concept for clastogenicity with topoisomerase II poisons.

1,4-alpha-D-glucan glucanohydrolase is among the most widely used commercial hydrolytic enzymes acting randomly on the glycosidic linkages of starch resulting in its saccharification and liquefaction. Its applicability in different industries can be improved by enhancing its stability and reusability. Therefore, in the present study attempts have been made to enhance the industrial applicability of 1,4-alpha-D-glucan glucanohydrolase from Bacillus subtilis KIBGE-HAR by adapting immobilization technology. The study developed mechanically stable, enzyme containing gel-frameworks using two support matrices including agar-agar, a natural polysaccharide and polyacrylamide gel, a synthetic organic polymer. These catalytic gel-scaffolds were compared with each other in terms of kinetics and stability of entrapped 1,4-α-D-glucan glucanohydrolase. In case of polyacrylamide gel, Km value for immobilized enzyme increased to 7.95 mg/mL, while immobilization in agar-agar resulted in decreased Km value i.e 0.277 mg/mL as compared to free enzyme. It was found that immobilized enzyme showed maximum activity at 70 °C in both the supports as compared to free enzyme having maximum activity at 60 °C. Immobilized 1,4-α-D-glucan glucanohydrolase exhibited no change in optimal pH 7.0 before and after entrapment in polyacrylamide gel and agar-agar. The enzyme containing gel-scaffold was found suitable for repeated batches of starch liquefaction in industrial processes. Agar-agar entrapped 1,4-α-D-glucanglucanohydrolase was capable to degrade starch up to seven repeated operational cycles whereas polyacrylamide entrapped enzyme conserved its activity up to sixth operational cycle.

Background: Nanotechnology brings a massive revolution in the domain of medical biotechnology. Plants possess thousands of antimicrobial compounds; these compounds can be extracted and utilized in the production of medicines. Objective: The aim of this research is to design an economic way for the formation of nanoparticles from plants and explore their antibacterial activity. Methods: In the present study, we used the plants, such as Aloe barbadensis, Azadirachta indica, Carica papaya, Mentha arvensis, and Catharanthus roseus. Ethanolic, methanolic, and aqueous extracts of the above-mentioned plants were used to prepare silver nanoparticles. Antimicrobial activities of the nanoparticles of extracts were determined against pathogenic strains of bacteria. Results: Results showed that silver nanoparticles are formed from the ethanolic and methanolic extracts of Azadirachta indica, Carica papaya, Mentha arvensis, and Catharanthus roseus and from the aqueous extracts of Aloe barbadensis and Mentha arvensis. It was observed that nanoparticles of ethanolic extracts of Azadirachta indica, Carica papaya, Mentha arvensis, and Catharanthus roseus exhibited the highest antibacterial activity against Pseudomonas species, E.coli, Pseudomonas specie, and S.typhi, respectively. On the other hand, the nanoparticles of methanolic extracts of Carica papaya, Mentha arvensis, and Catharanthus roseus showed the highest inhibition against E.coli, whereas, maximum zone of inhibition of Pseudomonas was observed by the action of methanolic extract of Azadirachta indica. It is also found that nanoparticles of the aqueous extracts of Aloe barbadensis and Mentha arvensis inhibited the pathogenic strains and showed maximum activity against Pseudomonas and E.coli, respectively. Conclusion: The above results indicate that the nanoparticles formed from the extracts of the tested plants have high antimicrobial potential and could be utilized in the preparation of medicines to treat various disorders.

The Corona Virus Pandemic that began in December 2019, brought a lot of changes in the World, not only in the healthcare sector, economic sector etc. but brought tremendous change in the education sector as well. Education plays a vital role in the holistic development of a person, however due to the coronavirus pandemic, a halt was put to this teaching-learning method all over the World to prevent the spread of the COVID-19. To provide education, the stakeholders in educational institutions decided to club the Internet and teaching together and e-learning thus was used at its peak during the Pandemic, thus students seated at home, through digitalization could study online. The objective of this study, was to understand the perceptions and opinion of Adolescents (14-25 years) towards online vs offline teaching-learning method. A Google Form questionnaire having both Qualitative and Quantitative Questions thus was circulated through snowball sampling and data from 150 participants was collected. The data collected was truly an eye opener. Majority of the participant's stated that they preferred Offline Teaching over Online Teaching. Majority of the participants stated that though online teaching has its own benefit and advantages but can never overpower offline learning Index terms: coronavirus, offline, online, social-media, teaching

Background and Objectives: Probiotics are nonpathogenic and beneficial viable microorganisms that exhibit potential health welfare for human beings. Probiotics are found in various food products. They also occur as natural microflora in the intestine of mammals. Main goal of this study was to isolate probiotics conferring antibacterial activity and cholesterol lowering ability from different fruits. Materials and Method: Present research reveals the usefulness of probiotics, in which twenty one bacterial cultures were isolated from different fruit samples including figs, coconut water and grapes. These strains were explored for their antibacterial and cholesterol reduction ability by conducting in vitro experiments. Results and Conclusion: Among twenty one isolates, nine probiotic cultures FgC2, FgC7, FgC14, G2C5, G1C,GrC18 and StCW showed maximum antibacterial activity against different human clinical pathogens. This suggests that these microbes produce inhibitory metabolites which are extracellular and diffusible. For cholesterol assimilation assay, six strains FgC2, FgC7,FgC12, FgC13, GrC7 and GrC18 presented remarkable cholesterol lowering efficacy (up to 98%) when grown in the presence of bile salts. Only potential probiotic cultures were identified and characterized as lactic acid bacteria (LAB), on the basis of Bergey’s Manual of Determinative Bacteriology. Thus this study is helpful to exploit the bioactive and therapeutic potential of beneficial microorganisms so that they can be utilized in the generation of functional food and other health promoting products.