Crystal Structure of Der f 7, a Dust Mite Allergen from Dermatophagoides farinae

10.1371/journal.pone.0044850PLoS ONE79

In vitro antibacterial activity of crude medicinal plant extracts against ampicillin+penicillin-resistant Staphylococcus aureus

Staphylococcus aureus is the leading cause for foodborne diseases. Extensive use of antibiotics has led to emergence of antibiotic-resistant S. aureus. Hence, interest on natural plant-based alternative which limits the use of synthetic chemicals is growing. The present work evaluated the antibacterial capacity of garlic, aloe vera, galangal, pineapple peel, neem, papaya leaf, lemongrass, peppermint, nutmeg and clove separately extracted with hexane, ethanol and water to a final concentration of 10% w/v against ampicillin+penicillin-resistant isolates of S. aureus in vitro. Streptomycin was used as a drug control against the resistant isolates; BRS023, BRS068 and DRS072. According to the interpretive standards for inhibition zone diameter provided by the Clinical and Laboratory Standards Institute, isolates BRS068 and DRS072 were considered resistant (≤ 12 mm), and isolate BRS023 was considered intermediate (13-14 mm). Against these isolates, all crude plant extracts exhibited varying degrees of inhibition. However, a coherent trend was observed in the inhibition between resistant and intermediate isolates regardless of plants and solvents used. It was also found that extraction solvent types impacted the resulting antibacterial activity. In terms of positive inhibition, the solvents were ranked in the order of hexane (77%) > water (73%) > ethanol (57%). 10% hexane extract of galangal gave the overall highest inhibition zones (17.8 ± 1.4 mm) closely followed by 10% ethanol extract of nutmeg (16.3 ± 1.1 mm). Further phytochemical analyses of the antibacterial compounds from galangal and nutmeg, and their minimum inhibitory concentration (MIC) are needed. Potential applications of plant-based antibacterial compounds as natural, costeffective and less-toxic food preservatives against drug-resistant foodborne pathogens should be explored

Ultrasound assisted extraction of nano calcium from waste eggshell: a preliminary study on crystal violet dye removal

Extraction of bio-based calcium carbonate (CaCO3) nanoparticles from eggshell waste materials assisted by horn-type ultrasonic generator was studied. Chicken eggshells (CS) and duck eggshells (DS) were cleaned and ground using pestle and mortar, and further treated with acetone and dichloromethane (DCM) to remove impurities. The treated eggshells were then ultrasonic irradiated for 5 to 20 min, before sending to Dynamic Light Scattering (DLS) for particle size distribution measurement. Results shown that, nano calcium with approximately 300 nm was being recovered successfully. The recovered nano calcium is later subjected to Crystal Violet (CV) dye removal testing and has recorded a high removal efficiency of up to 87.90 % and 83.06 % for DS and CS, respectively. The high removal efficiency is basically due to the large surface area on calcium nanoparticles created by ultrasonic cavitation, as confirmed by Scanning Electron Microscopy (SEM) analysis

Intention to Continue Adopting Online Problem-Based Learning After the COVID-19 Pandemic: Perception Analysis Using a Structural Equation Modelling Approach

Due to the coronavirus-19 pandemic, conventional face-to-face problem-based learning (PBL) had to be transitioned into online PBL. However, it was largely unknown how likely would medical students continue to adopt this form of hastily implemented remote learning solution after the pandemic ends. Using a two-stage partial least squares structural equation modelling approach, a study was conducted to (1) develop a set of questionnaires to measure this intention and (2) determine the influence of ‘perceived benefits’ (5 items) and ‘perceived ease of use’ (7 items) on the ‘behavioural intention to continue adopting’ online PBL. The technology acceptance model was adopted as the conceptual framework of this study. ‘Environment factors’ (11 items derived from PEST analysis where P = ‘policy’, E = ‘economic’, S = ‘social’, and T = ‘technology’ factors) were incorporated as the third independent construct in our model. A total of 149 Year 2 medical students participated in this study. Overall, the mean score for ‘behavioural intention to continue adopting’ online PBL was 3.42 out of 5 (where 1 = most unlikely and 5 = most likely). Only the construct ‘perceived ease of use’ had significant influence on the ‘behavioural intention to continue adopting’ online PBL (path coefficient standardised β = 0.312; t-statistics = 2.960; p = 0.003). ‘Perceived benefits’ and ‘environment factors’ were not shown to have significant influence. In conclusion, as no strong intention to continue adopting online PBL was demonstrated in this study, conventional face-to-face PBL should be resumed until clear benefits of a carefully designed online PBL can be demonstrated

A five-year retrospective review of snakebite patients admitted to a tertiary university hospital in Malaysia

BACKGROUND Although the majority of the snakebite cases in Malaysia are due to non-venomous snakes, venomous bites cause significant morbidity and mortality if treatment measures, especially ant-venom therapy, are delayed. METHODS To determine the demographic characteristics, we conducted a retrospective study on all snakebite patients admitted to the Emergency Department of Hospital Universiti Sains Malaysia (HUSM) from January 2006 to December 2010. RESULTS In the majority of the 260 cases that we found (138 cases or 52.9%), the snake species was unidentified. The most common venomous snakebites among the identified species were caused by cobras (52 cases or 20%). Cobra bites are significantly more likely to result in severe envenomation compared to non-cobra bites. Post hoc analysis also showed that cobra bite patients are significantly less likely to have complete recovery than non-cobra bite patients (48 cases, 75.0% vs. 53 cases, 94.6%; p = 0.003) and more likely to result in local gangrene (11 cases, 17.2% vs. 3 cases, 5.4%; p = 0.044). CONCLUSION Cobra bites are significantly more likely to result in severe envenomation needing anti-venom administration and more likely to result in local gangrene, and the patients are significantly less likely to have complete recovery than those with non-cobra bites

Identifying SARS-CoV-2 antiviral compounds by screening for small molecule inhibitors of Nsp3 papain-like protease

The COVID-19 pandemic has emerged as the biggest life-threatening disease of this century. Whilst vaccination should provide a long-term solution, this is pitted against the constant threat of mutations in the virus rendering the current vaccines less effective. Consequently, small molecule antiviral agents would be extremely useful to complement the vaccination program. The causative agent of COVID-19 is a novel coronavirus, SARS-CoV-2, which encodes at least nine enzymatic activities that all have drug targeting potential. The papain-like protease (PLpro) contained in the nsp3 protein generates viral non-structural proteins from a polyprotein precursor, and cleaves ubiquitin and ISG protein conjugates. Here we describe the expression and purification of PLpro. We developed a protease assay that was used to screen a custom compound library from which we identified dihydrotanshinone I and Ro 08-2750 as compounds that inhibit PLpro in protease and isopeptidase assays and also inhibit viral replication in cell culture-based assays

A clinical diagnostic model for predicting influenza among young adult military personnel with febrile respiratory illness in Singapore

10.1371/journal.pone.0017468PLoS ONE63

Impact of COVID-19 on liver transplantation in Hong Kong and Singapore: A modelling study

Liver transplantation (LT) activities during the COVID-19 pandemic have been curtailed in many countries. The impact of various policies restricting LT on outcomes of potential LT candidates is unclear. We studied all patients on the nationwide LT waitlists in Hong Kong and Singapore between January 2016 and May 2020. We used continuous time Markov chains to model the effects of different scenarios and varying durations of disruption on LT candidates

Destabilization of β Cell FIT2 by saturated fatty acids alter lipid droplet numbers and contribute to ER stress and diabetes

Western-type diets are linked to obesity and diabetes partly because of their high–saturated fatty acid (SFA) content. We found that SFAs, but not unsaturated fatty acids (USFAs), reduced lipid droplets (LDs) within pancreatic β cells. Mechanistically, SFAs, but not USFAs, reduced LD formation by inducing S-acylation and proteasomal, mediated degradation of fat storage–inducing transmembrane protein 2 (FIT2), an endoplasmic reticulum (ER) resident protein important for LD formation. Targeted ablation of FIT2 reduced β cell LD numbers, lowered β cell ATP levels, reduced Ca(2+) signaling, dampened vesicle exocytosis, down-regulated β cell transcription factors, up-regulated unfolded protein response genes, and finally, exacerbated diet-induced diabetes in mice. Subsequent mass spectrometry studies revealed increased C16:0 ceramide accumulation in islets of diet-induced diabetes mice lacking β cell FIT2. Inhibition of ceramide synthases ameliorated the enhanced ER stress and improved insulin secretion. FIT2 was reduced in mouse diabetic islets, and separately, overexpression of FIT2 increased the number of intracellular LDs and rescued SFA-induced ER stress and apoptosis, thereby highlighting the protective role of FIT2 and LDs against β cell lipotoxicity