Mosquito larvicidal and antimicrobial activity of protein of Solanum villosum leaves

<p>Abstract</p> <p>Background</p> <p>Mosquitoes are associated with the transmission of malaria, dengue, Japanese encephalitis, filariasis and other viral diseases throughout the globe, apart from being a nuisance pest. Biological control alone or as a part of integrated vector management stands to be a better alternative to the chemical controls aimed against pest mosquitoes. At the same time it is necessary to control bacteria by synthetic or natural means (plant products). Hence the present study was designed to screen the effect of mosquito larvicidal and antimicrobial activitiy of protein isolated from matured leaves of <it>Solanum villosum </it>against mosquito immatures and some pathogenic bacteria.</p> <p>Methods</p> <p>Aqueous solvent extract of fresh mature leaves of <it>S. villosum </it>was tested against 3rd instar larvae of <it>Anopheles stephensi</it>, <it>Culex quinquefasciatus </it>and <it>Stegomyia aegypti </it>mosquitoes and against four pathogenic bacteria. The protein fraction was isolated and tested for mosquitocidal and antibacterial activities. Amino acid analysis was performed on isolated protein using PICO.TAG amino acid system. SDS-PAGE was also done to detect the bands of amino acid on the basis of their molecular weights.</p> <p>Results</p> <p>Proteins isolated from mature leaves of <it>S. villosum </it>were found to have larvicidal and antimicrobial properties. Analysis of the isolated protein identified fifteen amino acids of which eight were essential amino acids. SDS-PAGE detected seven bands corresponding to different molecular weights in the range of 69–109 KDa.</p> <p>Conclusion</p> <p>Proteins of mature leaves of <it>S. villosum </it>exhibited moderate larvicidal and antimicrobial activities. The study provides considerable scope in exploiting local indigenous resources for isolation of antimicrobial and mosquito larvicidal proteins.</p

Optoelectronic characterisation of twisted germanium sulfide nanowires with experimental observation of intrinsic ferroelectricity

We report the optoelectrical characterisation of Eshelby twisted Germanium sulfide (GeS) nanowires with first experimental observation of ferroelectric order at room temperature in GeS which is an otherwise centrosymmetric molecule. The chemical composition and structure of these nanowires were confirmed by various spectroscopic, microscopic and diffractive techniques. In addition, the nanowires were found to be stable over time. From the optoelectronic measurements we found that these p-type semiconducting GeS nanowires have up to two orders higher charge carrier mobility than GeS nanosheets and have sustainable, robust photo-switching property. The existence of room temperature ferroelectricity is confirmed by piezoresponse force microscopy which showed hysteresis and butterfly loop, characteristics of a ferroelectric material. Our observations reveal that the properties of twisted GeS nanowires can be harnessed in making efficient electric sensors, photodetectors, data memories and flexible electronics

Metabolomics using Gas chromatography-mass spectrometry and antibacterial activity of nine Ocimum taxa of Dakshin Dinajpur district, West Bengal, India

Ocimum traditionally known as Holy Basil or Tulsi is an available herb plenty across the country. Traditionally, it is used against a number of human diseases. In this present study, the metabolites present in the ethanolic extracts of nine Ocimum taxa, O. tenuiflorum L. (Green and purple type) two morphotypes  of O. basilicum L., (Babu and Marua tulsi) two morphotypes  of O. gratissimum L. (Ram and Ajowan tulsi) and each one  from O. americanum L. (Bon tulsi), O. × africanum Lour. (Lebu tulsi), and O. kilimandscharicum Guerke.grown naturally in Dakshin Dinajpur district, West Bengal, India were identified using Gas chromatography–mass spectrometry  (GC-MS). Among the identified metabolites, carbohydrates, aliphatic alcohols, aliphatic acids, fused ring aromatic hydrocarbon, amino acids, phenolic compounds, quinone, steroids, terpenoids and vitamin E were the chief constituents. The occurrence of these metabolites describes the high biological activity of Ocimum species. Furthermore, in vitro antibacterial activities were also identified against four bacterial strains, Staphylococcus aureus (MTCC 96), Bacillus cereus (MTCC 1305), Proteus vulgaris (MTCC 1771) and Escherichia coli (MTCC 2939). Tested bacterial strains were taken from the Institute of Microbial Technology, Chandigarh, India The results indicated that the ethanolic extracts of all the nine Ocimum taxa have satisfactory minimum inhibitory concentration (MIC) values against the tested microorganisms. O. tenuiflorum has the highest (91.03 %) metabolic content whereas O. × africanum has the minimum. This would definitely serve as a scientific basis of the traditional use of basil against human ailments.

Turbine blade failure in a thermal power plant

The failure of a LP (low pressure) turbine blade of a 220 MW thermal power plant is presented. The blade was made of martensitic stainless steel and the structure was tempered martensite. There was no evidence of degradation of blade material. The fracture took place at the aerofoil region, 113-mm from the root. Throughout the blade surface Si rich phases were detected. Several pits/grooves were found on the edges of the blades and chloride was detected in these pits. These were responsible for the crevice type corrosion. The probable carriers of Cl− were Ca and K, which were found on the blade. The failure mode was intergranular type. Possibly the ultimate failure was due to corrosion-fatigue

Skyrmions and magnetic bubbles in spin-orbit coupled metallic magnets

Motivated by the observation of Skyrmion-like magnetic textures in 2D itinerant ferromagnets Fe$_n$GeTe$_2$ ($n \geq3$), we develop a microscopic model combining itinerant magnetism and spin-orbit coupling on a triangular lattice. The ground state of the model in the absence of magnetic field consists of filamentary magnetic domain walls revealing a striking similarity with our magnetic force microscopy experiments on Fe$_3$GeTe$_2$. In the presence of magnetic field, these filaments were found to break into large size magnetic bubbles in our experiments. We identify uniaxial magnetic anisotropy as an important parameter in the model that interpolates between magnetic Skyrmions and ferromagnetic bubbles. Consequently, our work uncovers new topological magnetic textures that merge properties of Skyrmions and ferromagnetic bubbles

Sub-clinical mastitis prevalent in dairy cows in Chittagong district of Bangladesh: detection by different screening tests

Aim: Mastitis is recognized as one of the most costly health disorder affecting dairy cows. An epidemiological study was carried out at some selected farms in Chittagong district of Bangladesh to determine the prevalence and risk factors of sub-clinical mastitis (SCM) in dairy cows. Materials and Methods: For conducting the study, some dairy farms of Chittagong were selected from urban and periurban areas by stratified random sampling. A total of 444 quarter samples of 111 (56 from commercial dairy farms and 55 from backyards) lactating dairy cows were considered. Sub-clinical mastitis (SCM) was determined using three different indirect screening tests: California Mastitis Test (CMT), White Slide Test (WST) and Surf Field Mastitis Test (SFMT). Sensitivity and specificity were also determined to measure the accuracy of those tests. Results: The prevalence of SCM by CMT, WST and SFMT were 32.43% (n=144), 33.56% (n=149) and 31.53% (n=140), respectively. Distribution of SCM in relation to different variables at quarter level and animal level was also recorded. The prevalence of SCM was significantly (P<0.05) higher in aged, high yielding cows in addition with history of periparturient diseases, without dry cow therapy both at quarter and animal level. A significantly (p<0.01) higher prevalence (48.98%) of SCM was observed in higher parity number (>4) than others at quarter level. No significant difference (P>0.05) was found in relation to breed. Using CMT as a gold standard, sensitivity and specificity of WST and SFMT were also calculated at 95% confidence interval. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, negative predictive value and disease prevalence by WST and SFMT were comparable. Conclusion: This study recommends that regular screening of sub-clinical mastitis will reduce the prevalence of sub-clinical mastitis. The most effective way to control sub-clinical mastitis is to take preventive measures such as regular cleaning of the floor, keeping the udder clean, milkman's cleanliness, dry cow therapy specially in high yielding dairy cows

BERBERINE HYDROCHLORIDE COULD PROVE TO BE A PROMISING BULLET AGAINST CLOSTRIDIUM DIFFICILE INFECTION: A PRELIMINARY STUDY FROM SOUTH INDIA

Objective: Recurrent Clostridium difficile infection (CDI) and the emergence of strains with reduced susceptibility to metronidazole and vancomycinwarrants alternative therapy. Hence, we tested the potential efficacy of the natural compound berberine hydrochloride (BBRHCl) against toxigenicC. difficile.Methods: Three representative polymerase chain reaction confirmed, toxin-positive strains were included in the study. Pulsed-field gel electrophoresis(PFGE) profile and antibiogram of the strains were analyzed along with 10 other toxin positive isolates. Efficacy of BBRHCl against toxigenic C. difficilewas determined using agar diffusion by punch well method.Results: PFGE grouped the test strains into three clusters with unique susceptibility pattern toward standard antibiotics. BBRHCl was efficaciousagainst the test strains at a concentration ranging between 6.25 μg/ml and 10 mg/ml. BBRHCl's breakpoint point inhibitory zone diameter wasequivalent (p&lt;0.001) to the epidemiological cutoff values for teicoplanin, vancomycin and 2% black seed oil. Although the predicted concentration ofBBRHCl for breakpoint zone diameter equivalent to European Committee on Antimicrobial Susceptibility Testing's epidemiological cutoff value formetronidazole was observed to fall outside the tested concentration range; it was still within the safe dosage for humans.Conclusion: The present study is promising in considering BBRHCl as a potent substitute or adjunct not only for metronidazole, vancomycin andteicoplanin but also for natural compounds like 2% black seed oil for managing resistant cases of CDI. Owing to BBRHCl's direct antibacterial and antiinflammatoryaction, further investigations will aid in the proper characterization of the therapeutic effects of similar plant compounds, to developsafe and effective drugs against the epidemiological outbreak of CDI

Influence of Austempering Temperature on Microstructure and Mechanical Properties of Cast Fe-Si-Mn-VSteel

The present investigation was carried out to examine the influence of austempering temperature on the micro-structure and mechanical properties of a low carbon, high silicon (C-0.13%, Si-1.2%, Mn-1%, V-0.08%) cast steels. The Induction melted casting block was homogenized at 1000°C for 6 hrs. The samples for microstructure and the tens-ile specimens were prepared from the cast steel block according to ASTM standards and were imparted three diff-erent austempering heat treatments to produce different microstructure. The samples are austenitisation at 900°C for 30 minute and then rapidly quenched to a salt bath maintained at temperature 350/400/450°C for 10 minute and then finally air cooled. The microstructure were observed under optical and TEM microscopy. show that UTS decreases but % El increases with increasing apstempering tempe-rature. The 400°C austempering temperature exhibited the best combination of UTS and %EI at room temperature (UTS-663 MPa, EL-26%) with revealing microstructure of bainite and retained austenite