Impact of HIV-1 subtype and antiretroviral therapy on protease and reverse transcriptase genotype: results of a global collaboration

BackgroundThe genetic differences among HIV-1 subtypes may be critical to clinical management and drug resistance surveillance as antiretroviral treatment is expanded to regions of the world where diverse non-subtype-B viruses predominate.ConclusionGlobal surveillance and genotypic assessment of drug resistance should focus primarily on the known subtype B drug-resistance mutations.     

Seed to seedling transitions in successional habitats across a tropical landscape

Recognition that tree recruitment depends on the balance between seed arrival and seedling survival has led to a surge of interest in seed‐dispersal limitation and seedling‐establishment limitation in primary forests. Virtually unaddressed are comparisons of this balance in mature and early successional habitats. We assessed seed rain and seedling recruitment dynamics of tree species in primary forest, secondary forest and pasture released from grazing in a tropical agricultural landscape. Seed to seedling ratios (seed effectiveness; Φ_i) for 43 species in southern Mexico determined differences in the extent to which seeds produced seedlings by habitat, life history, and dispersal mode. Reproductive potential as estimated by the transition from seed rain to seedling recruitment, differed by habitats, and varied dramatically by life history and dispersal mode. Expected recruit densities (E_it) were higher for animal‐dispersed than wind‐dispersed species, and for non‐pioneer than pioneer species. Non‐pioneers and animal‐dispersed species had higher expected relative recruit abundance (ε_it) in primary forest (median of 4 seeds recruit^?1) whereas in secondary forest wind‐dispersed pioneers had the highest expected relative recruit abundance (median of 16 seeds per recruit). In pastures, wind‐dispersed pioneer species were most successful with many more seeds per recruit (median of 291) than both forest habitats. Seeds per recruit (Φ_i) appeared to decrease with increase in seed mass for 43 species for which data were available (r = –0.55, P < 0.001). This was associated with a negative correlation of Φ_i with seed size in primary forest (r = –0.50, P = 0.08 for 13 species); Φ_i was not correlated with seed size in secondary forest (n = 16) or pasture (n = 14). Metrics of seeds per recruit, expected recruit density and expected relative recruit abundance dramatically illustrate differences in barriers to recruitment in successional habitats.     

Diversity and diversification of Eumolpinae (Coleoptera: Chrysomelidae) in New Caledonia

Contemporary taxonomic work on New Caledonian Eumolpinae (Chrysomelidae) has revealed their high species richness in this Western Pacific biodiversity hotspot. To estimate total species richness in this community, we used rapid DNA‐based biodiversity assessment tools, exploring mtDNA diversity and phylogenetic structure in a sample of 840 specimens across the main island. Concordance of morphospecies delimitation with units delimited by phenetic and phylogenetic algorithms revealed some 98–110 species in our sample, twice as many as currently described. Sample‐based rarefaction curves and species estimators using these species counts doubled this figure (up to 210 species), a realistic estimate considering taxonomic coverage, local endemism, and characteristics of sampling design, amongst others. New Caledonia, compared with larger tropical islands, stands out as a hotspot for Eumolpinae biodiversity. Molecular dating using either chrysomelid specific rates or tree calibration using palaeogeographical data dated the root of the ingroup tree (not necessarily a monophyletic radiation) at 38.5 Mya, implying colonizations after the Cretaceous breakage of Gondwana. Our data are compatible with the slowdown in diversification rates through time and are also consistent with recent faunal origins, possibly reflecting niche occupancy after an initial rapid diversification. Environmental factors (e.g. soil characteristics) seemingly played a role in this diversification process. © 2013 The Linnean Society of London     

Neurotoxic Effect of Intranigral Injection of 1-Methyl-4-Phenylpyridinium on GABA-Containing Neurons and Its Relation to Circling Behavior

Abstract: The ionic species 1-methyl-4-phenylpyridinium (MPP⁺) seems to be the metabolite responsible for the damage to dopaminergic neurons occurring after administration of the parkinsonian drug 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. In the present study we show that the unilateral stereotaxic microinjection of MPP⁺ into the substantia nigra pars reticulata in rats produces immediately intense and long-lasting (up to 96 h) contralateral turning behavior in a dose-dependent manner. This behavioral effect was correlated with a dose- and time-dependent decrease (up to 90%) of glutamate decarboxylase activity and with a notable loss of neurons in the injected nigra reticulata. GABA levels in the injected nigra were also decreased, whereas the dopamine concentration in the ipsilateral striatum was not affected at 24 h, when maximal behavioral effects were observed. The circling behavior was prevented by the dopamine carrier blocker nomifensine only during the first 2 h, whereas the dopamine receptor antagonist haloperidol was ineffective. The results indicate that MPP⁺ is toxic for inhibitory GABAergic neurons in the nigra pars reticulata and, furthermore, suggest that disruption of the function of these GABAergic neurons may be involved in the abnormal motor behavior produced by the injection of MPP⁺ in the substantia nigra.     

Hypolipidemic and antiatherosclerotic potential of Pleurotus ostreatus, cultived by submerged fermentation in the high-fat diet fed rats

The ability of Pleurotus ostreatus biomass, cultived by submerged fermentation, to produce beneficial effect on lipid profile and macrophages activity during a high-fat diet (HFD) for a long-term intake was investigated. Blood samples were collected through cardiac puncture to measure the plasma cholesterol, triglycerides, low-density protein (LDL), high-density protein (HDL), aspartate aminotransferase (AST) activity, urea-blood urea nitrogen (BUN)/creatinine ratio of rats fed on an HFD for 4 months. Dosage of lipid hydroperoxides was carried out on methanolic extract of liver tissue. Peritoneal macrophages activity was evaluated in relation to the superoxide anion, hydrogen peroxide and nitric oxide production, phagocytosis and lysosomal volume. The administration of P. ostreatus significantly altered the lipid profile and oxidative stress as related to the LDL and triglycerides decrease and inhibitory effects on superoxide anion and hydrogen peroxide production. All findings of this study lead us to suggest that the P. ostreatus maybe a beneficial agent in the hyperlipidemia and atherosclerosis treatments.     

Impact of unilateral spatial neglect on chronic patient's post-stroke quality of life

Abstract

Background: Unilateral spatial neglect (USN) is the prevalent feature in patients with right-sided stroke. It is diagnosed through the behavior inattention test (BIT) and has a negative impact on patients affecting both their functional capacity and quality of life.

Objective: Here, we aimed to evaluate the impact of USN on the quality of life of patients in the chronic phase of stroke.

Methods: This is a cross-sectional study with stroke patients with USN. After confirming the presence of stroke through neuroimaging examinations and of USN through the BIT, patients’ quality of life was evaluated by using the EUROQOL scale. Spearman’s correlation was used to validate the correlation between patients’ USN and quality of life, with a p?<?.05 representing significant results.

Results: Eighteen individuals were included. When correlating the value of each domain of the EUROQOL scale with the results of the BIT, we observed a negative correlation between mobility (r?=?–0.97; p?=?.000), self-care (r?=?–0.82; p?=?.013), usual activities (r?=?–0.87; p?=?.005); pain or discomfort (r?=?–0.88; p?=?.004), anxiety or depression (r?=?–0.97; p?=?.000), and EUROQOL total score (r?=?–0.97, p?=?.000).

Conclusion: After a correlation between the overall EUROQOL and BIT scores, we suggest that the higher the USN degree is in stroke patients, the worse their perceived quality of life tends to be.     

The “χ” of the Matter: Testing the Relationship between Paleoenvironments and Three Theropod Clades

The view of spinosaurs as dinosaurs of semi-aquatic habits and strongly associated with marginal and coastal habitats are deeply rooted in both scientific and popular knowledge, but it was never statistically tested. Inspired by a previous analysis of other dinosaur clades and major paleoenvironmental categories, here we present our own statistical evaluation of the association between coastal and terrestrial paleoenvironments and spinosaurids, along with other two theropod taxa: abelisaurids and carcharodontosaurids. We also included a taphonomic perspective and classified the occurrences in categories related to potential biases in order to better address our interpretations. Our main results can be summarized as follows: 1) the taxon with the largest amount of statistical evidence showing it positively associated to coastal paleoenvironments is Spinosauridae; 2) abelisaurids and carcharodontosaurids had more statistical evidence showing them positively associated with terrestrial paleoenvironments; 3) it is likely that spinosaurids also occupied spatially inland areas in a way somehow comparable at least to carcharodontosaurids; 4) abelisaurids may have been more common than the other two taxa in inland habitats.     

Model Construction and Analysis of Respiration in Halobacterium salinarum

The archaeon Halobacterium salinarum can produce energy using three different processes, namely photosynthesis, oxidative phosphorylation and fermentation of arginine, and is thus a model organism in bioenergetics. Compared to its bacteriorhodopsin-driven photosynthesis, less attention has been devoted to modeling its respiratory pathway. We created a system of ordinary differential equations that models its oxidative phosphorylation. The model consists of the electron transport chain, the ATP synthase, the potassium uniport and the sodium-proton antiport. By fitting the model parameters to experimental data, we show that the model can explain data on proton motive force generation, ATP production, and the charge balancing of ions between the sodium-proton antiporter and the potassium uniport. We performed sensitivity analysis of the model parameters to determine how the model will respond to perturbations in parameter values. The model and the parameters we derived provide a resource that can be used for analytical studies of the bioenergetics of H. salinarum.     

Hydrology Affects Environmental and Spatial Structuring of Microalgal Metacommunities in Tropical Pacific Coast Wetlands

The alternating climate between wet and dry periods has important effects on the hydrology and therefore on niche-based processes of water bodies in tropical areas. Additionally, assemblages of microorganism can show spatial patterns, in the form of a distance decay relationship due to their size or life form. We aimed to test spatial and environmental effects, modulated by a seasonal flooding climatic pattern, on the distribution of microalgae in 30 wetlands of a tropical dry forest region: the Pacific coast of Costa Rica and Nicaragua. Three surveys were conducted corresponding to the beginning, the highest peak, and the end of the hydrological year during the wet season, and species abundance and composition of planktonic and benthic microalgae was determined. Variation partitioning analysis (as explained by spatial distance or environmental factors) was applied to each seasonal dataset by means of partial redundancy analysis. Our results show that microalgal assemblages were structured by spatial and environmental factors depending on the hydrological period of the year. At the onset of hydroperiod and during flooding, neutral effects dominated community dynamics, but niche-based local effects resulted in more structured algal communities at the final periods of desiccating water bodies. Results suggest that climate-mediated effects on hydrology can influence the relative role of spatial and environmental factors on metacommunities of microalgae. Such variability needs to be accounted in order to describe accurately community dynamics in tropical coastal wetlands.     

Antifeedant Activity of <i>Caesalpinia coriaria</i> Essential Oil Against <i>Incisitermes marginipennis</i> (Latreille)

This study scrutinized the possibility of finding toxicant or deterrent plant metabolites against the dry wood termite Incisitermes marginipennis (Latreille). Plant deterrent agents act as repellents or antifeedants to prevent wood decay and increase its useful life. The potential of the tree Caesalpinia coriaria (Fabaceae) as a biological source of molecules with deterrent effects against the dry wood termite was assessed by a phytochemical fractionation guided by repellence and antifeedant activities. The gas chromatography-mass spectrometry analysis of the leaf essential oil showed geraniol to be one of the major components and its repellent and antifeedant effects were determined. Geraniol had only an antifeedant effect without affecting the body weight or survival of the dry wood termite. Unlike the leaf essential oil, geraniol did not exhibit a repellency effect. An in-silico approach of the activity of acetylcholinesterase in interaction with geraniol resulted in an affinity energy of −7.5 Kcal/mol. Geraniol interacted with the amino acid tyrosine 324 located in the enzyme’s active site while citronellol (negative control) interacted with tryptophan 83 located adjacent to the active site. These deterring terpenes have not been implemented for the preservation and restoration of wood products exposed to the attack of the dry wood termite. However, they are an important natural control alternative.