Chlamydosporol,a new metabolite from Fusarium chlamydosporum

Extracts of rice on which an isolate of Fusarium chlamydosporum had been cultured were toxic to brine shrimps. The toxic fraction was purified by flash chromatography to give two compounds which were identified by UV, IR, NMR and mass spectroscopy at the 6 and 6 isomers of 5-hydroxy-4-methoxy-6, 8a-dimethyl-6,7-dihydro-2H,8aH-pyrano[2,3-b]pyran-2-one. These lactones for which the name chlamydosporol is proposed have not been reported previously. When tested in brine shrimp and HeLa cell assays, the LC₅₀ concentration for a mixture of the isomers was approximately 400 g/ml in both systems.     

Xylem Fluids of White Lupin (Lupinus albus) Cultivars Susceptible and Resistant to Fusarium oxysporum f. sp. Lupini Race 3

Xylem fluids from white lupin cv. Neuland, susceptible to wilt causes by Fusarium oxysporum f. sp. lupini , promoted germination of conidia and chlamydospores of he pathogen, and the production of micro-conidia, to a greater extent than did xylem fluids from the resistant cv. Primorskij No sugars, organic acids or phenolic compounds were detected in the xylem fluids, but a number of amino acids were found, and the concentration of some differed in xylem fluids from the two cultivars; on the whole, concentrations were greater in the susceptible cv. Neuland. Synthetic amino acids were supplied to the fungus in vitro and both stimulatory and inhibitory effects (according to the compound and its concentration) were noted upon the germination of conidia and chlamydospores and on mycelial growth and the production of conidia. The role of amino acids and other compounds in the susceptibility of white lupin to wilt is discussed.     

Activation of nylon by alkaline glutaraldehyde solution for enzyme immobilisation

Summary Nylon tube was directly activated by alkaline glutaraldehyde solution. PEI was utilised as a spacer molecule. Glucose oxidase was immobilised to the nylon tube after reactivating the spacer molecules with glutaraldehyde. On immobilising glucose oxidase there was more protein binding and higher immobilised enzyme activity when compared to immobilised enzyme tube activated by triethyloxonium salt. The optimal condition for direct glutaraldehyde activation of nylon was incubation with 18.5% (w/v) glutaraldehyde in 0.12M borate pH 9.0 for 15 min at 90 °.     

Stochastic multi-scale prediction on the apparent elastic moduli of trabecular bone considering uncertainties of biological apatite (BAp) crystallite orientation and image-based modelling

An assessment of the mechanical properties of trabecular bone is important in determining the fracture risk of human bones. Many uncertainty factors contribute to the dispersion of the estimated mechanical properties of trabecular bone. This study was undertaken in order to propose a computational scheme that will be able to predict the effective apparent elastic moduli of trabecular bone considering the uncertainties that are primarily caused by image-based modelling and trabecular stiffness orientation. The effect of image-based modelling which focused on the connectivity was also investigated. A stochastic multi-scale method using a first-order perturbation-based and asymptotic homogenisation theory was applied to formulate the stochastically apparent elastic properties of trabecular bone. The effective apparent elastic modulus was predicted with the introduction of a coefficient factor to represent the variation of bone characteristics due to inter-individual differences. The mean value of the predicted effective apparent Young's modulus in principal axis was found at approximately 460 MPa for respective 15.24% of bone volume fraction, and this is in good agreement with other experimental results. The proposed method may provide a reference for the reliable evaluation of the prediction of the apparent elastic properties of trabecular bone.     

New Insights of Microsporidial Infection among Asymptomatic Aboriginal Population in Malaysia

Background

Studies on microsporidial infection mostly focus on immunodeficiency or immunosuppressive individuals. Therefore, this cross-sectional study describes the prevalence and risk factors of microsporidiosis among asymptomatic individuals in Malaysia.

Methods/Findings

Four hundred and forty seven stool samples were collected and examined for microsporidia after staining with Gram-chromotrope Kinyoun. Demographic, socioeconomic, environmental, and behavioral information were collected by using a pre-tested questionnaire. Overall, 67 (15%) samples were positive for microsporidia. The prevalence of infection was significantly higher among individuals aged more than 15 years compared to those aged <15 years (OR = 1.97, 95% CI = 1.08, 3.62; P = 0.028). Furthermore, logistic regression analysis confirmed that the presence of other family members infected with microsporidia (OR = 8.45; 95% CI = 4.30, 16.62; P<0.001) and being a consumer of raw vegetables (OR = 2.05; 95% CI = 1.15, 3.66; P = 0.016) were the significant risk factors of this infection.

Conclusions

These findings clearly show that exposure to microsporidia is common among Aboriginal population. Further studies using molecular approach on microsporidia isolates from asymptomatic individuals is needed to determine species-specific. The risk factors associated with microsporidiosis will help in identifying more clearly the sources of the infection in the environment that pose a risk for transmission so that preventive strategies can be implemented.     

Fusarium Species Associated with Mango Malformation in Peninsular Malaysia

Mango malformation has become the most important global disease on mango. Fusarium species previously associated with this disease include F. mangiferae, F. mexicanum, F. sterilihyphosum, F. proliferatum, F. subglutinans and F. tupiense. A few strains of F. proliferatum have been reported from Malaysia, but in this study, we report the results of more extensive sampling. The recovered strains were evaluated with morphology, mating tester strain cross‐fertility, amplified fragment length polymorphisms (AFLPs), and partial DNA sequences of the genes encoding translation elongation factor 1‐α (tef‐1α) and β‐tubulin (tub‐2). Amongst the 43 strains evaluated, three species were identified – F. proliferatum, F. mangiferae and F. subglutinans – with F. proliferatum being the most frequent (69%). None of the Fusarium species that appear to originate in the Americas were recovered in Malaysia, which suggests special measures may be warranted to keep these species from entering the country.     

Thermal tolerance and climate warming sensitivity in tropical snails

Tropical ectotherms are predicted to be especially vulnerable to climate change because their thermal tolerance limits generally lie close to current maximum air temperatures. This prediction derives primarily from studies on insects and lizards and remains untested for other taxa with contrasting ecologies. We studied the HCT (heat coma temperatures) and ULT (upper lethal temperatures) of 40 species of tropical eulittoral snails (Littorinidae and Neritidae) inhabiting exposed rocky shores and shaded mangrove forests in Oceania, Africa, Asia and North America. We also estimated extremes in animal body temperature at each site using a simple heat budget model and historical (20 years) air temperature and solar radiation data. Phylogenetic analyses suggest that HCT and ULT exhibit limited adaptive variation across habitats (mangroves vs. rocky shores) or geographic locations despite their contrasting thermal regimes. Instead, the elevated heat tolerance of these species (HCT = 44.5 ± 1.8°C and ULT = 52.1 ± 2.2°C) seems to reflect the extreme temperature variability of intertidal systems. Sensitivity to climate warming, which was quantified as the difference between HCT or ULT and maximum body temperature, differed greatly between snails from sunny (rocky shore; Thermal Safety Margin, TSM = −14.8 ± 3.3°C and −6.2 ± 4.4°C for HCT and ULT, respectively) and shaded (mangrove) habitats (TSM = 5.1 ± 3.6°C and 12.5 ± 3.6°C). Negative TSMs in rocky shore animals suggest that mortality is likely ameliorated during extreme climatic events by behavioral thermoregulation. Given the low variability in heat tolerance across species, habitat and geographic location account for most of the variation in TSM and may adequately predict the vulnerability to climate change. These findings caution against generalizations on the impact of global warming across ectothermic taxa and highlight how the consideration of nonmodel animals, ecological transitions, and behavioral responses may alter predictions of studies that ignore these biological details.     

Lipase-catalyzed dimethyl adipate synthesis: Response surface modeling and kinetics

Dimethyl adipate (DMA) was synthesized by immobilized Candida antarctica lipase B-catalyzed esterification of adipic acid and methanol. To optimize the reaction conditions of ester production, response surface methodology was applied, and the effects of four factors namely, time, temperature, enzyme concentration, and molar ratio of substrates on product synthesis were determined. A statistical model predicted that the maximum conversion yield would be 97.6%, at the optimal conditions of 58.5°C, 54.0 mg enzyme, 358.0 min, and 12:1 molar ratio of methanol to adipic acid. The R² (0.9769) shows a high correlation between predicted and experimental values. The kinetics of the reaction was also investigated in this study. The reaction was found to obey the ping-pong bi-bi mechanism with methanol inhibition. The kinetic parameters were determined and used to simulate the experimental results. A good quality of fit was observed between the simulated and experimental initial rates.     

A potential tocopherol acetate loaded palm oil esters-in-water nanoemulsions for nanocosmeceuticals

Background  

Cosmeceuticals are cosmetic-pharmaceutical hybrids intended to enhance health and beauty of the skin. Nanocosmeceuticals use nano-sized system for the delivery of active ingredients to the targeted cells for better penetration. In this work, nanoemulsion from palm oil esters was developed as a delivery system to produce nanocosmeceuticals. The stability of the resulting formulation was tested using various methods. In addition, the effect of components i.e. Vitamin E and Pluronic F-68 on the formulation was also studied.