P. AMERICANA AS AN INTESTINAL CARRIER OF NOSOCOMIAL AND FOOD BORNE BACTERIAL PATHOGENS

The study was undertaken to search the carrier potential of P. americana, the predominant cockroach species in India, of various human bacterial pathogen including L. monocytogenes in their intestine. Cockroaches were collected from tertiary care hospitals, domestic environments, market places and restaurants. Identification of the bacterial isolates from the aseptically removed intestine was carried out by standard bacteriological procedures (Cowan and Steel, 1974) including morphological, cultural, biochemical and physiological studies. Listeria species were isolated following USDA method. The bacteriological examination of the intestinal content of P. americana  revealed the presence of various potential human bacterial pathogens including Listeria spp. The major bacteria with epidemiological significance in nosocomial infection isolated from the intestinal contents of P. americana were Enterococcus spp. (95.6percent), Klebsiella spp. (39.6percent) and Proteus spp. (36percent).51.2percent of cockroaches under study were found to be harboured with Listeria spp. The observations made in this study establish the possible role of the insect P. americana in carrying and transmitting human pathogens especially in nosocomial and food borne infections and goes to suggest that the pest cannot be ignored as a casual harmless inhabitant of the human environments.Keywords: P. americana, intestine, bacterial pathogen

ANTIDERMATOPHYTIC AND PROTEASE INHIBITING ACTIVITIES OF THE RHIZOME OF ZINGIBER ZERUMBET (L) ROSCOE EX J. E: SMITH FROM CENTRAL KERALA, INDIA

Objective: Determination of Antidermatophytic and protease inhibiting activities of the rhizome of Zingiber zerumbet from central Kerala, India.Methods: Dried and powdered rhizomes of Zingiber zerumbet were extracted with methanol at room temperature. Antidermatophytic activity of the extract was tested against Epidermophyton floccosum var. nigricans, Microsporum canis, Microsporum gypseum and Trichophyton rubrum by determining the percentage inhibition of mycelial growth. Minimum inhibitory concentration (MIC) and fungicidal concentration (MFC) of the extract were determined according to CLSI method–M38-A2 with slight modification. Protease inhibiting activity was analysed using trypsin as the enzyme. Results: The methanolic extract of the rhizome of Zingiber zerumbet exhibited 100 percentage inhibition of mycelial growth of tested dermatophytes at the concentration 1 mg/ml. The inhibitory effect was statistically significant with P=0.000. MIC of the extract was 0.5 mg/ml against all organisms while MFC were 0.7, 0.8, 0.9 and 0.8 mg/ml respectively for E. floccosum, M. canis, M. gypseum and T. rubrum. The percentage inhibition of trypsin activity by 100µg, 500µg and 1000µg of the extract were 33.12±0.95, 56.34±2.82 and 72.93±1.16 respectively.Conclusion: The rhizome of Zingiber zerumbet exhibited anti dermatophytic as well as trypsin inhibiting activity. The material is a traditionally used ingredient in food preparations. Hence it can be used for the development of less toxic medicaments for dermatophytoses and inflammatory diseases in traditional as well as modern medicine.Â

Identification of two strains of Paenibacillus sp. as indole 3 acetic acid-producing rhizome-associated endophytic bacteria from Curcuma longa

Curcuma longa is well known for its use as spice and medicine. The remarkable feature of the plant is the presence of rhizome, which provides an interesting habitat for association by various groups of bacteria. Some of these associated endophytic bacteria can have growth-promoting effects. In the current study, two species of endophytic Paenibacillus has been identified from the rhizome as indole 3 acetic acid producers. These isolates can thus have potential growth-regulating effect in rhizomes

Corrosion analysis and performance investigation of hybrid MXene/C-dot Nanofluid-Based direct absorption solar collector

Nanofluids having exceptional thermo-optical characteristics can enhance the performance of direct absorption solar collectors (DASC). Conventional nanofluids have either high optical properties or thermal properties. In this study, carbon quantum dot (C-dot) nanomaterial with high stability and optical absorption along the UV range, and MXene nanoparticles with high thermal conductivity and absorption along visible and near-infrared (NIR) spectral range was selected for synthesizing a hybrid nanomaterial with synergistic thermo-optical properties. Hybrid MXene/C-dot nanofluid exhibits higher stability, thermal conductivity, and complementary absorption properties of individual nanomaterials. A two-step method was used for the synthesis of nanofluids using water as the base fluid. Thermal conductivity, UV–Vis-NIR spectroscopy, and stability analysis were conducted on nanofluids, and the concentration was optimized for corrosion study and application in direct absorption parabolic trough collector (DAPTC). Optimised concentrations of C-dot, MXene, and hybrid nanofluids were 0.15 wt%, 0.1 wt% and 0.15 wt%, respectively. The corrosion study states that copper electrodes dipped in the hybrid nanofluid exhibited the least corrosion rate of 0.6 mm/year with an anticorrosion efficiency of 64.5 % over DI water. Thermal efficiency and entropy generation in the system with different HTFs were measured and compared with that of the base fluid. The study shows that C-dot and MXene/C-dot nanofluids were producing the highest efficiencies of 50.5 % and 47.5 % at a flow rate of 1.2 lpm. This study shows that hybrid MXene/C-dot nanofluid exhibited exceptional thermal stability, reduced corrosion effects, and considerable enhancement in photothermal conversion efficiency of the DASC

Trypsin inhibiting activity of methanolic extract of aerial parts of Mikania micrantha

ABSTRACT Objective: To investigate trypsin inhibiting activity of methanolic extract of aerial parts of Mikania micrantha.Methods: Powdered plant material was extracted with methanol at room temperature and trypsin inhibiting activity of the extract was studied using bovine serum albumin (BSA) as the substrate. Result: Percentage inhibition of trypsin activity by the methanolic extract of aerial parts of Mikania micrantha wer

Mosquito Larvicidal Activity of Chitinase of Pseudomonas putida Mb 12 against the Human Vector Aedes aegypti

The main dengue and Zika vector, Aedes aegypti, is a cosmotropic species. Since dengue fever cases have significantly increased in recent years, these organisms seem to be extremely detrimental. Synthetic pesticides are not biodegradable, are non-selective, and have adverse effects on beneficial organisms being handled in the vector management system. In the present study, the mosquitocidal potential of chitinase from P. putida Mb 12 was evaluated in an effort to identify risk-free options for the control of mosquitoes. Larvicidal toxicity of Pseudomonas putida Mb 12 chitinase were evaluated on IVth-instar larva of Ae. aegypti and their effect on acetylcholinesterase activity and glutathione S-transferase activity were studied. The early 4th instar larvae of Ae. aegypti were exposed to chitinase enzyme concentrations of 50U/mL, 100U/mL, 200U/mL, and 500U/mL for a period of 4 hours to assess their effectiveness. The results showed that as chitinase concentration increased, mosquito larvae mortality increased; after 4 hours, chitinase at 500 U/mL caused 100% mortality. After 4 hours of incubation, 200 U/mL was administered to achieve LC50 (which kills 50% of the exposed organisms), and after 3 hours, 500 U/mL was used to obtain LC90 values. During the study, it was discovered that different quantities of chitinase (100 U/mL, 200 U/mL, and 500 U/mL) inhibited 80% of the activity of the acetylcholinesterase enzyme. This study found that chitinase significantly increased glutathione S-transferase activity. Additionally, it was discovered that the chitinase treatment was non-hazardous to guppy fish. It was assumed that the P. putida Mb 12 chitinase tested was safe to employ in the aquatic habitat because no mortality was observed in the non-target organisms

ANTIBIOTIC RESISTANCE PROFILE OF BACTERIAL PATHOGENS IN THE GUT OF P. AMERICANA

The study was conducted to determine the antibiotic sensitivity of various bacterial isolates including L. monocytogenes obtained from the intestinal content of P. americana captured from hospitals, domestic environments, restaurants and market places. The antimicrobial susceptibility of the bacterial isolates was determined by Kirby-Bauer disk diffusion method. Among the different groups of antibiotics, cephalosporins resistance was obvious in all the bacterial isolates under study. E. faecium, the most predominant isolate in the study, showed noticeable resistance to penicillin (39percent), erythromycin (35percent) and cloxacillin (32percent) apart from its cephalosporin resistance. Among the Gram negative isolates, though resistance to quinolones was not as apparent as cephalosprins, tendency to resist nalidixic acid was evident particularly in P. aeruginosa (79percent). Resistance to penicillin, nalidixic acid was noticed in all the Listeria species under study. The multidrug resistant bacteria carried by the omnipresent insect cockroach in their intestine as noticed in this study urges the necessity of further epidemiological studies for revealing the role of this insect in nosocomial infection and food spoilage.Key wordsP. americana, bacterial pathogens, antibiotic sensitivit

Plant growth and diosgenin enhancement effect of silver nanoparticles in Fenugreek (Trigonella foenum-graecum L.)

Various methods have been used to enhance production of chemically diverse phytochemicals especially medicinal natural products. With the advancement in nanotechnology, nanoparticles have been reported to have varying impact in plant growth and inducibility of phytochemical composition. Major objective of the study was to study the secondary metabolite modulatory effect of silver nanoparticles. In the current study, treatment of fenugreek seedlings with biosynthesized silver nanoparticles (Ag-NPs) was found to have significant impact on its growth parameters such as leaf number, root length, shoot length and wet weight. On HPLC based analysis, Ag-NPs treated seedlings showed an enhancement in the production of major phytochemical diosgenin to a level of 214.06 ± 17.07 μg/mL. An untreated control gave an yield of only 164.44 ± 7.67 μg/mL of diosgenin, and the observed phytochemical enhancement effect induced by Ag-NP was very significant. Most remarkably, the Ag-NP used in the study was found to play dual role of enhancement of both plant growth and diosgenin synthesis. Hence the study is of immense application as it opens up development of new methods based on nanoelicitors to enhance the biosynthesis of medicinal natural products in plants

A Review on the Prospective Applications of Fungal Keratinases

Keratin is the most abundant insoluble protein in the epithelial cells of vertebrates and represents the major constituents of skin, hair, feathers, wool, and nails. It is among the hardest-to-degrade animal protein, the major component in poultry feathers. Keratinases are exciting proteolytic enzymes that display the capability to degrade the insoluble protein keratin, recalcitrance to common proteolytic enzymes like pepsin, trypsin, and papain. Keratinases are versatile enzymes gaining momentum in the field of Biotechnology with potential applications. As the keratin is too hard to degrade, substrates like hair, hoof, horn, feather nail etc. can be treated effectively with keratinases, which is considered as the remarkable application of the enzyme. The poultry feather degradation using keratinase improve the nutritional value of feather meal and can be applied for the production of rare amino acids like proline, cysteine, serine, and methionine. The potential use of these enzymes have been associated with cosmetic industry and acne treatment. The other applications of keratinase include the production of biofuel, detergent, films, coatings, glues and pesticidal toxins, degumming of silk, scale removal from wool fibre, degradation of prions etc. Keratinases are mainly produced by different microorganisms like fungi and bacteria which are considered as biodegradable, eco-friendly enzymes without any harmful effects like that of the chemical counterparts. As the separation of bacterial keratinase is a cost intensive process compared to fungal keratinase, the review is focussed on isolation, purification and prospective applications of fungal keratinase