An amperometric biosensor based on laccase immobilized onto MnO2NPs/cMWCNT/PANI modified Au electrode

A method is described for construction of an amperometric biosensor for detection of phenolic compounds based on covalent immobilization of laccase (Lac) onto manganese dioxide nanoparticles (MnO(2)NPs) decorated carboxylated multiwalled carbon nanotubes (cMWCNTs)/PANI composite electrodeposited onto a gold (Au) electrode through N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxy succinimide (NHS) chemistry. The modified electrode was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The biosensor showed optimum response at pH 5.5 (0.1M sodium acetate buffer) and 35°C, when operated at 0.3 V vs. Ag/AgCl. Linear range, response time, detection limit were 0.1-10 μM (lower concentration range) and 10-500 μM (higher concentration range), 4s and 0.04 μM, respectively. Biosensor measured total phenolic content in tea leaves extract. The enzyme electrode was used 150 times over a period of 5 months.     

Assessing the performance of the photo‐acoustic infrared gas monitor for measuring CO2, N2O,and CH4 fluxes in two major cereal rotations

Rapid, precise, and globally comparable methods for monitoring greenhouse gas (GHG) fluxes are required for accurate GHG inventories from different cropping systems and management practices. Manual gas sampling followed by gas chromatography (GC) is widely used for measuring GHG fluxes in agricultural fields, but is laborious and time‐consuming. The photo‐acoustic infrared gas monitoring system (PAS) with on‐line gas sampling is an attractive option, although it has not been evaluated for measuring GHG fluxes in cereals in general and rice in particular. We compared N₂O, CO_2, and CH₄ fluxes measured by GC and PAS from agricultural fields under the rice–wheat and maize–wheat systems during the wheat (winter), and maize/rice (monsoon) seasons in Haryana, India. All the PAS readings were corrected for baseline drifts over time and PAS‐CH₄ (PCH₄) readings in flooded rice were corrected for water vapor interferences. The PCH₄ readings in ambient air increased by 2.3 ppm for every 1000 mg cm^?3 increase in water vapor. The daily CO₂, N₂O, and CH₄ fluxes measured by GC and PAS from the same chamber were not different in 93–98% of all the measurements made but the PAS exhibited greater precision for estimates of CO₂ and N₂O fluxes in wheat and maize, and lower precision for CH₄ flux in rice, than GC. The seasonal GC‐ and PAS‐N₂O (PN₂O) fluxes in wheat and maize were not different but the PAS‐CO₂ (PCO₂) flux in wheat was 14–39% higher than that of GC. In flooded rice, the seasonal PCH₄ and PN₂O fluxes across N levels were higher than those of GC‐CH₄ and GC‐N₂O fluxes by about 2‐ and 4fold, respectively. The PAS (i) proved to be a suitable alternative to GC for N₂O and CO₂ flux measurements in wheat, and (ii) showed potential for obtaining accurate measurements of CH₄ fluxes in flooded rice after making correction for changes in humidity.     

The influence of larval diet on adult feeding behaviour in the tobacco hornworm moth, Manduca sexta

Lab-reared sphingid and noctuid moths appear to feed less than wild moths, and often are starved to enhance responsiveness in feeding assays. To measure the impact of larval nutrition on adult feeding, we raised a model sphingid species, Manduca sexta, on control or modified diets (reduced sugar, protein or water, supplemented beta-carotene) or cut tobacco leaves, then conducted feeding assays with artificial flowers. Behaviour was scored and analysed in a double-blind manner. Larval diet affected adult eclosion time, size and fat content, the latter of which was inversely proportional to moth approaches to the floral array in a flight cage. In contrast, behaviours refractory to feeding (sitting, escaping) were associated with sex and barometric pressure, but not with diet or fat content. Frequency of floral approaches and probing was not associated with any variable. However, moths reared on beta-carotene-supplemented diet were 2-3 times more likely to feed, and significantly less likely to sit or show "escape" behaviour than were moths from most other treatments. Our results suggest that decreased visual sensitivity, rather than increased fat content, accounts for reduced adult feeding by lab-reared M. sexta.     

Extra precision glide docking,free energy calculation and molecular dynamics studies of 1,2-diarylethane derivatives as potent urease inhibitors

For the latter half of the twentieth century, most medical professionals considered bacterial infection to be a primary cause of gastrointestinal ulcers in human beings. In 1994, the World Health Organization (WHO) recognized Helicobacter pylori, the bacterium most closely linked to ulcer development, as a type I carcinogen. Biological research has shown that there is a positive correlation between the number of species in the Helicobacter genus and the number of medical conditions associated with Helicobacter infection, both of which are increasing rapidly. N-Benzylaniline derivatives, frequently used in industrial manufacturing, are being considered as a strong candidate for ongoing drug modeling in search of novel therapies. The basic goal behind this study was to determine the potency of experimentally proved data, and to determine favorable substituents to enhance potency, and thereafter to support this finding through theoretical modification of the existing base skeleton by addition of suitable substituents. Ligands were investigated thoroughly by paying attention to the urease-inhibitory properties present in the selected series. Initially, docking was performed on ligands with protein to produce efficient docking poses. Molecular dynamics (MD) simulations were also performed to precisely understand the interactions between ligands and proteins. Thereafter, MM-GBSA was used in order to validate the methods and results. Good interaction was observed with amino acids Arg338, Ala169, Asp223, His322, and Asn168. This study also revealed that the electron rich hydroxyl group (–OH) substituent plays an important role during bond formation. In addition, various hydrogen bonds, ionic bonds, and pi–pi stacking bonds make significant contributions towards urease inhibition. Therefore, further research utilizing electron-rich moieties may lead to novel and efficacious urease inhibitors.     

The influence of bile salts on the response of liposomes to ultrasound

Context: Triggering drug release from delivery vehicles with ultrasound has potential applications in targeted drug delivery. It was hypothesized that the addition of bile salts would increase the sensitivity of liposomes to ultrasound through creation of defects.

Objective: The aim of this study was to investigate whether incorporating bile salts into liposomes would lead to differential effects on their response to low and high frequency ultrasound.

Materials and methods: Cholate, chenodeoxycholate, ursodeoxycholate, glycocholate and taurocholate were the selected bile salts. Response to ultrasound was characterized by measuring the release of carboxyfluorescein (CF).

Results: At 30?kHz ultrasound, taurocholate containing liposomes were most responsive and released 70% (±2) CF after 30 seconds of sonication. Compared to this, liposomes that did not contain bile salts released just 7% (±2). At 1.1?MHz ultrasound, all liposome formulations were unresponsive. To increase the response of liposomes at 1.1?MHz ultrasound, a combination of membrane destabilizers were added to DSPC liposomes. DOPE, a hexagonal phase lipid was used in combination with taurocholate. Surprisingly, liposomes containing DOPE and taurocholate were more resistant to 1.1?MHz ultrasound than ones containing only DOPE.

Discussion: This suggests that the sensitivity of liposomes towards ultrasound may not simply be defined by a single membrane component but instead depends on the interaction between constituting lipid components. Furthermore, strategies other than membrane destabilization may be required to sensitize liposomes towards high frequency ultrasound.

Conclusion: Bile salts may be used to increase or decrease the sensitivity of liposomes to low frequency ultrasound.     

Or47b-neurons promote male-mating success in Drosophila

Drosophila performs elaborate well-defined rituals of courtship, which involve several types of sensory inputs. Here, we report that Or47b-neurons promote male-mating success. Males with Or47b-neurons silenced/ablated exhibit reduced copulation frequency and increased copulation latency. Copulation latency of Or47b-manipulated flies increased proportionately with size of the assay arena, whereas in controls it remained unchanged. While competing for mates, Or47b-ablated males are outperformed by intact controls. These results suggest the role of Or47b-neurons in promoting male-mating success.