RESUMO A combinação de antibióticos e nanoparticulas podem ser usadas para tratamento terapêutico de microoganismos multi-resistentes. Nanoparticulas (NPs) tem sido relatada com atividade antimicrobial. A atividade antimicrobial de nanopartículas de ZnO dopadas (ZnO NPs) foram estudas contra fungos, e bactérias gram-postivas e gram-negativas, usando o método de microdiluição. A interação entre as nanoparticulas e antibioticos foi estimada por cálculos de Concentração Inibitória Fracionada (FIC índice) da combinação através do ensaio do Tabuleiro de Xadrez. Os resultados demonstraram que as nanopartículas de Oxido de Zinco dopadas 10% (ZnO NPs) exibem o máximo efeito antimicrobiano em contraste com aquelas carregadas em 1% e as puras ZnO nanoparticulas. O aumento do efeito antimicrobiano foi observado quando combinadas com antibióticos. Efeitos sinérgicos e aditivos foram observados. Não foram observados efeitos de antagonismo. Maior efeito sinérgico foi observado quando combinado com ciprofloxania e ampicilina. Fungos apresentaram somente efeito aditivo. Os resultados estão de acordo com MIC mostrando claramente que agentes com alta dopagem são mais propícios para terapia combinada. 100% de interação sinergística foi observada na maior dopagem com ciprofloxacina e ampicilina. Este estudo fornece um relato preliminar da atividade sinergística de nanopartículas com antibióticos contra diferentes linhagens patogênicas. Isto fornece base para novos estudos em relação a terapia combinada de nanopartículas com antibióticos.

ABSTRACT Combination therapy of antibiotics and nanoparticles can be used against multi drug resistant microorganisms. Nanoparticles (NPs) have been reported to show antimicrobial activity. The antimicrobial activities of doped ZnO nanoparticles (ZnO NPs) were studied against fungi, gram-positive and gram-negative bacteria using the standard microdilution method. The interaction between the nanoparticle and the antibiotic was estimated by calculating the fractional inhibitory concentration (FIC index) of the combination through checkerboard assay. Experimental results demonstrated that 10% doped zinc oxide nanoparticles (ZnO NPs) exhibited the maximum antimicrobial effect in contrast with that of the 1% loading and pure ZnO nanoparticles. The enhancement in antimicrobial effect was seen when combined with antibiotic. Synergistic and additive effects were found. No antagonistic effect was found. More synergistic effect was observed when combined with ciprofloxacin than ampicillin. Fungus showed only additive effect. The results are quite in terms with MIC clearly depicting that high doping agent is most suitable for combined therapy. 100% synergistic interaction was observed in higher doping with both ciprofloxacin and ampicillin. This study provides a preliminary report of the synergistic activity of nanoparticles with antibiotics against different pathogenic strains. This provides groundwork for further studies on the combination therapy of nanoparticles with antibiotics.

Aspergillus niger F7 isolated from soil was found to be the potent producer of cellulase and xylanase. The residue of forest species Toona ciliata, Celtris australis, Cedrus deodara and Pinus roxburghii was selected as substrate for biodegradation study due to its easy availability and wide use in industry. It was subjected to alkali (sodium hydroxide) treatment for enhancing its degradation. Biodegradation of forest waste by hydrolytic enzymes (cellulase and xylanase) secreted by A. niger under solid state fermentation (SSF) was explored. SSF of pretreated forest biomass was found to be superior over untreated forest biomass. Highest extracellular enzyme activity of 2201±23.91 U/g by A. niger was shown in pretreated C. australis wood resulting in 6.72±0.20 percent hydrolysis and 6.99±0.23 biodegradation index (BI). The lowest BI of 1.40±0.08 was observed in untreated saw dust of C. deodara having the least enzyme activity of 238±1.36 U/g of dry matter. Biodegradation of forest biomass under SSF was increased many folds when moistening agent i.e. tap water had been replaced with modified basal salt media (BSM). In BSM mediated degradation of forest waste with A. niger, extracellular enzyme activity was increased up to 4089±67.11 U/g of dry matter in turn resulting in higher BI of 15.4±0.41 and percent hydrolysis of 19.38±0.81 in pretreated C. australis wood. A. niger exhibited higher enzyme activity on pretreated biomass when moistened with modified BSM in this study. Statistically a positive correlation has been drawn between these three factors i.e. enzyme activity, BI and percent hydrolysis of forest biomass thus proving their direct relationship with each other.

Synthesis of 2-amino-5-substituted-1,3,4-oxadiazoles through the electrochemical oxidation of semicarbazone was carried out at platinum anode at room temperature under controlled potential electrolysis in an undivided cell assembly. The electrolysis were carried out in the non aqueous medium acetic acid and lithium perchlorate was used as a supporting electrolyte. The antimicrobial activities of the compounds have been studied by screening the compounds against two gram negative organisms Klebsiella pneumoniae, Escherichia coli, and two gram positive organisms Bacillus subtilis and Streptococcus aureus and antifungal activity against Aspergillus niger and Crysosporium pannical and results have been compared with the standard antibacterial Streptomycin and antifungal Griseofulvin.