Detoxification of 2,4-dichlorophenol by the marine microalga Tetraselmis marina

Xenobiotic chlorinated phenols have been found in fresh and marine waters and are toxic to many aquatic organisms. Metabolism of 2,4-dichlorophenol (2,4-DCP) in the marine microalga Tetraselmis marina was studied. The microalga removed more than 1mM of 2,4-DCP in a 2l photobioreactor over a 6 day period. Two metabolites, more polar than 2,4-DCP, were detected in the growth medium by reverse phase HPLC and their concentrations increased at the expense of 2,4-DCP. The metabolites were isolated by a C8 HPLC column and identified as 2,4-dichlorophenyl-beta-d-glucopyranoside (DCPG) and 2,4-dichlorophenyl-beta-d-(6-O-malonyl)-glucopyranoside (DCPGM) by electrospray ionization-mass spectrometric analysis in a negative ion mode. The molecular structures of 2,4-DCPG and 2,4-CPGM were further confirmed by enzymatic and alkaline hydrolyses. Thus, it was concluded that the major pathway of 2,4-DCP metabolism in T. marina involves an initial conjugation of 2,4-DCP to glucose to form 2,4-dichlorophenyl-beta-d-glucopyranoside, followed by acylation of the glucoconjugate to form 2,4-dichlorophenyl-beta-d-(6-O-malonyl)-glucopyranoside. The microalga ability to detoxify dichlorophenol congeners other than 2,4-DCP was also investigated. This work provides the first evidence that microalgae can use a combined glucosyl and malonyl transfer to detoxify xenobiotics such as dichlorophenols.     

A comparison of root architecture and shoot morphology between naturally regenerated and container-grown seedlings of Quercus ilex

We explored the different mechanisms developed by naturally regenerated seedlings of Quercus ilex L. (Holm oak) under Mediterranean conditions compared to container-seedlings commonly used in plantations. We examined the differences in root architecture (including topology and morphology) and shoot parameters. The results showed that there are many differences in the architecture of the root system as well as in the shoot morphology between the two types of seedlings. The naturally regenerated seedlings were smaller with regard to most of the shoot and root parameters, but they developed a longer taproot, only first order lateral roots, and presented a more herringbone-like root system compared to the container seedlings. Conversely, all types of container seedlings, were larger and had a more extended root system with many orders of lateral roots, while their taproot length was restricted within the container’s depth. The quotient log (α)/ log (μ) for all seedlings, showed a tendency to decrease with plant size. A strict herringbone root system with an elongated taproot may be the optimal root architecture for Quercus ilex L. seedlings in order to survive under Mediterranean conditions.     

Prediction of backbone dihedral angles and protein secondary structure using support vector machines

Background  

The prediction of the secondary structure of a protein is a critical step in the prediction of its tertiary structure and, potentially, its function. Moreover, the backbone dihedral angles, highly correlated with secondary structures, provide crucial information about the local three-dimensional structure.     

Optimization of Xylanase Production by Thermomyces Lanuginosus in Tomato Seed Meal Using Response Surface Methodology

Summary A 3² central composite experimental design was performed with the aim of optimizing xylanase production by Thermomyces lanuginosus grown on corn cobs in submerged cultures. Xylanase production was first tested on different nitrogen sources (tomato skin, tomato seed meal, corn steep liquor, meat peptone, bacto-tryptone and yeast extract). Tomato seed meal was the selected substrate to test the effect of two variables on xylanase production (corn cobs and tomato seed meal concentrations). A second-order quadratic model and a response surface method showed that the optimum condition for xylanase production was corn cobs 4.6% (w/v) and tomato seed meal 2.1% (w/v). The optimum conditions found were transferred to 7-l bioreactors, where activities as high as 1630 U/ml were obtained.     

Thermal, dynamic and structural properties of drug AT1 antagonist olmesartan in lipid bilayers

It is proposed that AT1 antagonists (ARBs) exert their biological action by inserting into the lipid membrane and then diffuse to the active site of AT1 receptor. Thus, lipid bilayers are expected to be actively involved and play a critical role in drug action. For this reason, the thermal, dynamic and structural effects of olmesartan alone and together with cholesterol were studied using differential scanning calorimetry (DSC), 13C magic-angle spinning (MAS) nuclear magnetic resonance (NMR), cross-polarization (CP) MAS NMR, and Raman spectroscopy as well as small- and wide angle X-ray scattering (SAXS and WAXS) on dipalmitoyl-phosphatidylcholine (DPPC) multilamellar vesicles. 13C CP/MAS spectra provided direct evidence for the incorporation of olmesartan and cholesterol in lipid bilayers. Raman and X-ray data revealed how both molecules modify the bilayer's properties. Olmesartan locates itself at the head-group region and upper segment of the lipid bilayers as 13C CP/MAS spectra show that its presence causes significant chemical shift changes mainly in the A ring of the steroidal part of cholesterol. The influence of olmesartan on DPPC/cholesterol bilayers is less pronounced. Although, olmesartan and cholesterol are residing at the same region of the lipid bilayers, due to their different sizes, display distinct impacts on the bilayer's properties. Cholesterol broadens significantly the main transition, abolishes the pre-transition, and decreases the membrane fluidity above the main transition. Olmesartan is the only so far studied ARB that increases the gauche:trans ratio in the liquid crystalline phase. These significant differences of olmesartan may in part explain its distinct pharmacological profile.     

Self-Administered Tuberculosis Treatment Outcomes in a Tribal Population on the Indo-Myanmar Border,Nagaland, India

Background

Multiple strategies are being adopted by national tuberculosis (TB) programmes to achieve universal coverage of tuberculosis treatment. However, populations living in ‘hard-to-reach’ areas of north-east India have poor access to health services. Our study aimed to detail treatment outcomes in TB program supported by Médecins Sans Frontières (MSF) and using an alternative model of TB treatment delivery in Mon district, Nagaland, India.

Methods

This was a retrospective cohort study of TB patients, initiated on self-administered therapy (SAT) through Mon District Hospital, Nagaland, India between April 2012 and March 2013.

Results

A total of 238 tuberculosis patients had final TB treatment outcomes during the study period, including 82 and 156 from semi-urban and rural areas respectively. The majority of patients (62%, 147/238) were suffering from pulmonary, smear-positive tuberculosis. Overall, 74% of patients (175/238) had successful outcomes, being cured or having completed their treatment. Females (81%), pulmonary TB patients (75%) and those on a Category I regimen (79%) had better treatment success rates than males (67%), extra-pulmonary TB patients (62%) and patients on a Category II regimen (61%). The univariate and bivariate analyses found age, sex and TB treatment regimen significantly associated with unsuccessful TB treatment outcomes (defined as death, loss-to-follow-up and failure). However, only older age showed significance in a multivariate binary logistic regression model.

Conclusion

Our study suggests that self-administered TB treatment is feasible for patients living in areas with limited or no access to health services. The relatively low number of patients with adverse outcomes suggests that SAT models are safe; other advantages include the need for fewer resources and less frequent movements by patients. National TB programmes should consider allowing SAT strategies for delivery of TB treatment to ‘hard-to-reach’ populations, which could in turn help to achieve universal coverage and contribute to global TB elimination by 2050.     

Integrating Linguistics,Social Structure,and Geography to Model Genetic Diversity within India

India represents an intricate tapestry of population substructure shaped by geography, language, culture, and social stratification. Although geography closely correlates with genetic structure in other parts of the world, the strict endogamy imposed by the Indian caste system and the large number of spoken languages add further levels of complexity to understand Indian population structure. To date, no study has attempted to model and evaluate how these factors have interacted to shape the patterns of genetic diversity within India. We merged all publicly available data from the Indian subcontinent into a data set of 891 individuals from 90 well-defined groups. Bringing together geography, genetics, and demographic factors, we developed Correlation Optimization of Genetics and Geodemographics to build a model that explains the observed population genetic substructure. We show that shared language along with social structure have been the most powerful forces in creating paths of gene flow in the subcontinent. Furthermore, we discover the ethnic groups that best capture the diverse genetic substructure using a ridge leverage score statistic. Integrating data from India with a data set of additional 1,323 individuals from 50 Eurasian populations, we find that Indo-European and Dravidian speakers of India show shared genetic drift with Europeans, whereas the Tibeto-Burman speaking tribal groups have maximum shared genetic drift with East Asians.