Bacterial reduction of hexavalent molybdenum to molybdenum blue

A bacterium that was able to tolerate and reduce as high as 50 mM of sodium molybdate to molybdenum blue has been isolated from a metal recycling ground. The isolate was tentatively identified as Serratia sp. strain Dr.Y8 based on the carbon utilization profiles using Biolog GN plates and partial 16S rDNA molecular phylogeny. ANOVA analysis showed that isolate Dr.Y8 produced significantly higher (P < 0.05) amount of Mo-blue with 3, 5.1 and 11.3 times more molybdenum blue than previously isolated molybdenum reducers such as Serratia marcescens strain Dr.Y6, E. coli K12 and E. cloacae strain 48, respectively. Its molybdate reduction characteristics were studied in this work. Electron donor sources such as sucrose, mannitol, fructose, glucose and starch supported molybdate reduction. The optimum phosphate, pH and temperature that supported molybdate reduction were 5 mM, pH 6.0 and 37°C, respectively. The molybdenum blue produced from cellular reduction exhibited a unique absorption spectrum with a maximum peak at 865 nm and a shoulder at 700 nm. Metal ions such as chromium, silver, copper and mercury resulted in approximately 61, 57, 80, and 69% inhibition of the molybdenum-reducing activity at 1 mM, respectively. The reduction characteristics of strain Dr.Y8 suggest that it would be useful in future molybdenum bioremediation.     

Genome Sequence of Acinetobacter baumannii AC12, a Polymyxin-Resistant Strain Isolated from Terengganu,Malaysia

Acinetobacter baumannii is a major cause of nosocomial infection worldwide. We report the draft genome sequence of A. baumannii AC12, a multidrug-resistant nosocomial strain with additional resistance to carbapenems and polymyxin. The genome data will provide insights into the genetic basis of antimicrobial resistance and its adaptive mechanism.     

Effect of Vitamin D Supplementation on Cardiometabolic Risks and Health-Related Quality of Life among Urban Premenopausal Women in a Tropical Country – A Randomized Controlled Trial

Background

Many observational studies linked vitamin D to cardiometabolic risks besides its pivotal role in musculoskeletal diseases, but evidence from trials is lacking and inconsistent.

Aim

To determine whether Vitamin D supplementation in urban premenopausal women with vitamin D deficiency can improve cardiometabolic risks and health-related quality of life (HRQOL).

Design

A double-blind randomized controlled trial was conducted in Kuala Lumpur, Malaysia. A total of 192 vitamin D deficient (<50 nmol/l) premenopausal women were randomized to receive either vitamin D 50,000 IU or placebo once a week for 2 months and then monthly for 10 months. Primary outcomes were serum 25(OH)D, serum lipid profiles, blood pressure and HOMA-IR measured at baseline, 6 months and 12 months. HRQOL was assessed with SF-36 at baseline and 12 months.

Results

Ninety three and ninety-nine women were randomised into intervention and placebo groups respectively. After 12 months, there were significant differences in the serum 25(OH)D concentration (mean difference: 49.54; 95% CI: 43.94 to 55.14) nmol/l) and PTH levels (mean difference: −1.02; 95% CI: −1.67 to −0.38 pmol/l) in the intervention group compared to placebo group. There was significant difference between treatment group in both serum 25(OH)D and PTH. There was no effect of supplementation on HOMA-IR, serum lipid profiles and blood pressure (all p>0.05) between two groups. There was a small but significant improvement in HRQOL in the components of vitality (mean difference: 5.041; 95% CI: 0.709 to 9.374) and mental component score (mean difference: 2.951; 95% CI: 0.573 to 5.329) in the intervention group compared to placebo group.

Conclusion

Large and less frequent dosage vitamin D supplementation was safe and effective in the achievement of vitamin D sufficiency. However, there was no improvement in measured cardiometabolic risk factors in premenopausal women. Conversely vitamin D supplementation improves some components of HRQOL.

Trial Registration

Australian New Zealand Clinical Trial Registry ACTRN12612000452897     

Middle East and North Africa consensus on osteoporosis

With the increasing life expectancy, osteoporosis is becoming a major worldwide health problem. The magnitude of the disease may become larger in developing countries, more particularly in the Middle East region where the prevalence of low bone mass is higher than in western countries. Although several local organizations and countries have developed guidelines for osteoporosis, no previous regional guidelines have been developed encompassing all Middle-Eastern and North African countries. The present document reviews all the regional published data on bone mineral density, risk factors, fracture prevalence and vitamin D status. It also gives simple recommendations applicable to all these countries. This document was endorsed by leading members of all the different regional countries including, Iran, Egypt, Tunisia, Jordan, Palestine, Syria, Iraq, Libya, Oman, Kuwait, Saudi Arabia and Bahrain.     

A Comparison of Assays for Accurate Copy Number Measurement of the Low-Affinity Fc Gamma Receptor Genes FCGR3A and FCGR3B

The FCGR3 locus encoding the low affinity activating receptor FcγRIII, plays a vital role in immunity triggered by cellular effector and regulatory functions. Copy number of the genes FCGR3A and FCGR3B has previously been reported to affect susceptibility to several autoimmune diseases and chronic inflammatory conditions. However, such genetic association studies often yield inconsistent results; hence require assays that are robust with low error rate. We investigated the accuracy and efficiency in estimating FCGR3 CNV by comparing Sequenom MassARRAY and paralogue ratio test-restriction enzyme digest variant ratio (PRT-REDVR). In addition, since many genetic association studies of FCGR3B CNV were carried out using real-time quantitative PCR, we have also included the evaluation of that method’s performance in estimating the multi-allelic CNV of FCGR3B. The qPCR assay exhibited a considerably broader distribution of signal intensity, potentially introducing error in estimation of copy number and higher false positive rates. Both Sequenom and PRT-REDVR showed lesser systematic bias, but Sequenom skewed towards copy number normal (CN = 2). The discrepancy between Sequenom and PRT-REDVR might be attributed either to batch effects noise in individual measurements. Our study suggests that PRT-REDVR is more robust and accurate in genotyping the CNV of FCGR3, but highlights the needs of multiple independent assays for extensive validation when performing a genetic association study with multi-allelic CNVs.     

Hexavalent molybdenum reduction to Mo-blue by <Emphasis Type="Italic">Acinetobacter calcoaceticus</Emphasis>

A local molybdenum-reducing bacterium was isolated and tentatively identified as Acinetobacter calcoaceticus strain Dr.Y12 based on carbon utilization profiles using Biolog GN plates and 16S rDNA comparative analysis. Molybdate reduction was optimized under conditions of low dissolved oxygen (37 °C and pH 6.5). Of the electron donors tested, glucose, fructose, maltose and sucrose supported molybdate reduction after 1 d of incubation, glucose and fructose supporting the highest Mo-blue production. Optimum Mo-blue production was reached at 20 mmol/L molybdate and 5 mmol/L phosphate; increasing the phosphate concentrations inhibited the production. An increase in an overall absorption profiles, especially at peak maximum at 865 nm and the shoulder at 700 nm, was observed in direct correlation with the increased in Mo-blue amounts. Metal ions, such as chromium, cadmium, copper, mercury and lead (2 mmol/L final concentration) caused ≈88, 53, 80, 100, and 20 % inhibition, respectively. Respiratory inhibitors, such as antimycin A, rotenone, sodium azide and cyanide showed in this bacterium no inhibition of the Mo-blue production, suggesting that the electron transport system is not a site of molybdate reduction.     

Sources of Canopy Chemical and Spectral Diversity in Lowland Bornean Forest

Sources of variation among the chemical and spectral properties of tropical forest canopies are poorly understood, yet chemical traits reveal potential ecosystem and phylogenetic controls, and spectral linkages to chemical traits are needed for remote sensing of functional and biological diversity. We analyzed 21 leaf traits in 395 fully sunlit canopies, representing 232 species and multiple growth forms, in a lowland mixed dipterocarp forest of Sarawak, Malaysia. Leaf traits related to light capture and growth (for example, photosynthetic pigments, nutrients) were up to 55% lower, and defense traits (for example, phenols, lignin) were 15–40% higher, in the dominant family Dipterocarpaceae and in its genus Shorea, as compared to all other canopy species. The chemical variation within Dipterocarpaceae and Shorea was equivalent to that of all other canopy species combined, highlighting the role that a single phylogenetic branch can play in creating canopy chemical diversity. Seventeen of 21 traits had more than 50% of their variation explained by taxonomic grouping, and at least 16 traits show a connection to remotely sensed spectroscopic signatures (RMSE < 15%). It is through these chemical-to-spectral linkages that studies of functional and biological diversity interactions become possible at larger spatial scales, thereby improving our understanding of the role of species in tropical forest ecosystem dynamics.     

Modulation of the innate immune system in white shrimp Litopenaeus vannamei following long-term low salinity exposure

Immune parameters, haemocyte lifespan, and gene expressions of lipopolysaccharide and β-glucan-binding protein (LGBP), peroxinectin (PX), integrin β, and α2-macroglobulin (α2-M) were examined in white shrimp Litopenaeus vannamei juveniles (0.48 ± 0.05 g) which had been reared at different salinity levels of 2.5‰, 5‰, 15‰, 25‰, and 35‰ for 24 weeks. All shrimp survived during the first 6 weeks. The survival rate of shrimp reared at 2.5‰ and 5‰ was much lower (30%) than that of shrimp reared at 15‰, 25‰, and 35‰ (76%~86%) after 24 weeks. Shrimp reared at 25% grew faster. Shrimp reared at 2.5‰ and 5‰ showed lower hyaline cells (HCs), granular cells (GCs), phenoloxidase activity (PO) activity, respiratory bursts (RBs), superoxide dismutase (SOD) activity, and lysozyme activity, but showed a longer haemocyte lifespan, and higher expressions of LGBP, PX, integrin β, and α2-M. In another experiment, shrimp which had been reared at different salinity levels for 24 weeks were challenged with Vibrio alginolyticus (6 × 10(6) cfu shrimp(-1)), and WSSV (10(3) copies shrimp(-1)) and then released to their respective seawater. At 96-144 h, cumulative mortalities of shrimp reared at 2.5‰ and 5‰ were significantly higher than those of shrimp reared at 15‰, 25‰, and 35‰. It was concluded that following long-term exposure to 2.5‰ and 5‰ seawater, white shrimp juveniles exhibited decreased resistance against a pathogen due to reductions in immune parameters. Increases in the haemocyte lifespan and gene expressions of LGBP, integrin β, PX, and α2-M indicated that shrimp had the ability to expend extra energy to modulate the innate immune system to prevent further perturbations at low salinity levels.     

Detection of Methicillin-Resistant Staphylococcus aureus Using mecA/nuc Genes and Antibiotic Susceptibility Profile of Malaysian Clinical Isolates

The aim of this study is to compare methicillin-resistant Staphylococcus aureus (MRSA) detection methods and to generate antibiogram profile of S. aureus clinical isolates from two teaching hospitals in Malaysia including three reference isolates from American Type Culture Collection (ATCC). The mecA/nuc gene PCR amplification, spot inoculation test and oxacillin disc diffusion test were applied to compare its MRSA detection abilities. No disagreement between the three methods was observed. From 29 bacterial isolates (including the ATCC strains) tested, 19 isolates were confirmed as S. aureus with 14 isolates exhibiting multidrug-resistance. All isolates are still susceptible to vancomycin as indicated by the E-test result. Current biochemical tests are comparable with the molecular detection method for MRSA used in this study while multidrug-resistance traits are present in both MRSA and MSSA clinical isolates. Presently, mupirocin seems to be the best alternative for vancomycin against multidrug-resistant S. aureus infections in Malaysia. Susceptibility profile of 19 S. aureus isolates acquired from two teaching hospitals and ATCC towards 16 selected antibiotics was analyzed and an antibiogram was generated. Findings also indicated resistance against many of the available antibiotics and thus an urgent need to search for alternative antibiotics.