Disturbances, elevation, topography and spatial proximity drive vegetation patterns along an altitudinal gradient of a top biodiversity hotspot

The correlation between vegetation patterns (species distribution and richness) and altitudinal variation has been widely reported for tropical forests, thereby providing theoretical basis for biodiversity conservation. However, this relationship may have been oversimplified, as many other factors may influence vegetation patterns, such as disturbances, topography and geographic distance. Considering these other factors, our primary question was: is there a vegetation pattern associated with substantial altitudinal variation (10–1,093 m a.s.l.) in the Atlantic Rainforest—a top hotspot for biodiversity conservation—and, if so, what are the main factors driving this pattern? We addressed this question by sampling 11 1-ha plots, applying multivariate methods, correlations and variance partitioning. The Restinga (forest on sandbanks along the coastal plains of Brazil) and a lowland area that was selectively logged 40 years ago were floristically isolated from the other plots. The maximum species richness (>200 spp. per hectare) occurred at approximately 350 m a.s.l. (submontane forest). Gaps, multiple stemmed trees, average elevation and the standard deviation of the slope significantly affected the vegetation pattern. Spatial proximity also influenced the vegetation pattern as a structuring environmental variable or via dispersal constraints. Our results clarify, for the first time, the key variables that drive species distribution and richness across a large altitudinal range within the Atlantic Rainforest.     

Transferability and characterization of microsatellite markers from Byrsonima cydoniifolia A. Juss. (MALPIGHIACEAE) in seven related taxa from Cerrado biome reveal genetic relationships

Byrsonima Rich. is one of the largest genera of the Malpighiaceae family with 97 species occurrence in Brazil and multiple potentialities, including pharmaceutical and food industries. In this study, 17 microsatellite markers characterized in Byrsonima cydoniifolia were tested for seven related taxa, all species are native to Brazil and four are endemic. Genomic DNA was extracted from leaves tissues and 17 microsatellite markers were used to cross-amplification of microsatellite regions. Polymorphism and genetic diversity were evaluated for B. intermedia, B. verbascifolia, B. laxiflora, B. subterranea, B. umbellata, B. linearifolia. from 16 individuals and for B. viminifolia from 14 individuals. Transferred microsatellite markers panels ranged from 11 (64.8%) in B. viminifolia to 6 (35.2%) in B. umbellata. The total number of alleles per locus ranged from 5 (B. linearifolia) to 8 (B. subterranea) alleles. B. umbellata showed lower values of observed and expected heterozygosity (H_O?=?0.312; H_E?=?0.436) and B. subterranea presented the highest values (H_O?=?0.687; H_E?=?0.778). A greater number of microsatellite markers should be developed for B. umbellata. The microsatellite marker panels transferred to the species B. intermedia, B. verbascifolia, B. laxiflora, B. subterranea, B. viminifolia and B. linearifolia are very informative, with a high combined probability of exclusion of paternity (Q?≥?0.976) and the low combined probability of identity (I?≤?9.91?×?10^–6), potentially suitable for future genetic-population studies, supporting strategies for maintaining the genetic diversity and for exploration of Byrsonima species as genetic resources.

     

Candidiasis: Predisposing Factors,Prevention, Diagnosis and Alternative Treatment

Candidiasis is the most common opportunistic yeast infection. Candida species and other microorganisms are involved in this complicated fungal infection, but Candida albicans continues to be the most prevalent. In the past two decades, it has been observed an abnormal overgrowth in the gastrointestinal, urinary and respiratory tracts, not only in immunocompromised patients, but also related to nosocomial infections and even in healthy individuals. There is a widely variety of causal factors that contribute to yeast infection which means that candidiasis is a good example of a multifactorial syndrome. Due to rapid increase in the incidence in these infections, this is the subject of numerous studies. Recently, the focus of attention is the treatment and, above all, the prevention of those complications. The diagnosis of candidiasis could become quite complicated. Prevention is the most effective “treatment,” much more than eradication of the yeast with antifungal agents. There are several aspects to consider in the daily routine that can provide a strength protection. However, a therapeutic approach is necessary when the infection is established, and therefore, other alternatives should be explored. This review provides an overview on predisposition factors, prevention and diagnosis of candidiasis, highlighting alternative approaches for candidiasis treatment.     

Candida riodocensis and Candida cellae, two new yeast species from the Starmerella clade associated with solitary bees in the Atlantic rain forest of Brazil

Two new ascomycetous yeast species belonging to the Starmerella clade were discovered in nests of two solitary bee species in the Atlantic rain forest of Brazil. Candida riodocensis was isolated from pollen-nectar provisions, larvae and fecal pellets of nests of Megachile sp., and Candida cellae was found in pollen-nectar provisions of Centris tarsata. Analysis of the sequences of the D1/D2 large-subunit ribosomal DNA showed that C. riodocensis is phylogenetically related to C. batistae, and the closest relative of C. cellae is C. etchellsii. The type strains are C. riodocensis UFMG-MG02 (=CBS 10087(T) = NRRL Y-27859(T)) and C. cellae UFMG-PC04 (=CBS 10086(T) = NRRL Y-27860(T)).     

Insulin regulates GLUT1-mediated glucose transport in MG-63 human osteosarcoma cells

Osteosarcoma is the most common type of malignant bone cancer, accounting for 35% of primary bone malignancies. Because cancer cells utilize glucose as their primary energy substrate, the expression and regulation of glucose transporters (GLUT) may be important in tumor development and progression. GLUT expression has not been studied previously in human osteosarcoma cell lines. Furthermore, although insulin and insulin-like growth factor (IGF-I) play an important role in cell proliferation and tumor progression, the role of these hormones on GLUT expression and glucose uptake, and their possible relation to osteosarcoma, have also not been studied. We determined the effect of insulin and IGF-I on GLUT expression and glucose transport in three well-characterized human osteosarcoma cell lines (MG-63, SaOs-2, and U2-Os) using immunocytochemical, RT-PCR and functional kinetic analyses. Furthermore we also studied GLUT isoform expression in osteosarcoma primary tumors and metastases by in situ hybridization and immunohistochemical analyses. RT-PCR and immunostaining show that GLUT1 is the main isoform expressed in the cell lines and tissues studied, respectively. Immunocytochemical analysis shows that although insulin does not affect levels of GLUT1 expression it does induce a translocation of the transporter to the plasma membrane. This translocation is associated with increased transport of glucose into the cell. GLUT1 is the main glucose transporter expressed in osteosarcoma, furthermore, this transporter is regulated by insulin in human MG-63 cells. One possible mechanism through which insulin is involved in cancer progression is by increasing the amount of glucose available to the cancer cell.     

Recombinant phospholipase A1 (Ves v 1) from yellow jacket venom for improved diagnosis of hymenoptera venom hypersensitivity

Background

Eosinophils are involved in various inflammatory processes including allergic inflammation during which angiogenesis has been documented. Angiogenesis is most likely connected to the hypoxia which characterizes inflamed tissues. Eosinophils produce VEGF and are pro-angiogenic. However, to the best of our knowledge no study has been performed to verify the existence of a direct link between eosinophils, hypoxia and angiogenesis in allergic inflammation.

Objective

To characterize eosinophil function and angiogenic potential under hypoxic conditions.

Methods

Human peripheral blood eosinophils were cultured in normoxic or hypoxic conditions with or without cytokines. Viability and apoptosis were assessed by Annexin V/PI staining. Anti- or pro-apoptotic protein levels, HIF-1α levels and MAPK phosphorylation were analyzed by immunoblot analysis. Angiogenic mediator release was evaluated by ELISA.

Results

Hypoxic eosinophils were more viable than normoxic ones after up to three days. In addition in hypoxia, anti-apoptotic Bcl-XL protein levels increased more than pro-apoptotic Bax levels. Hypoxia increased VEGF and IL-8 release. In hypoxic eosinophils high levels of HIF-1α were observed, particularly in the presence of GM-CSF. MAPK, particularly ERK1/2 inhibitors, decreased hypoxia-mediated VEGF release and HIF-1α expression.

Conclusion

Eosinophils respond to hypoxia by up-regulation of survival and of some of their pro-angiogenic functions indicating a correlation between eosinophilic inflammation and angiogenesis.     

Leptospirosis in Rio Grande do Sul,Brazil: An Ecosystem Approach in the Animal-Human Interface

Background

Leptospirosis is an epidemic-prone neglected disease that affects humans and animals, mostly in vulnerable populations. The One Health approach is a recommended strategy to identify drivers of the disease and plan for its prevention and control. In that context, the aim of this study was to analyze the distribution of human cases of leptospirosis in the State of Rio Grande do Sul, Brazil, and to explore possible drivers. Additionally, it sought to provide further evidence to support interventions and to identify hypotheses for new research at the human-animal-ecosystem interface.

Methodology and findings

The risk for human infection was described in relation to environmental, socioeconomic, and livestock variables. This ecological study used aggregated data by municipality (all 496). Data were extracted from secondary, publicly available sources. Thematic maps were constructed and univariate analysis performed for all variables. Negative binomial regression was used for multivariable statistical analysis of leptospirosis cases. An annual average of 428 human cases of leptospirosis was reported in the state from 2008 to 2012. The cumulative incidence in rural populations was eight times higher than in urban populations. Variables significantly associated with leptospirosis cases in the final model were: Parana/Paraiba ecoregion (RR: 2.25; CI_95%: 2.03–2.49); Neossolo Litolítico soil (RR: 1.93; CI_95%: 1.26–2.96); and, to a lesser extent, the production of tobacco (RR: 1.10; CI_95%: 1.09–1.11) and rice (RR: 1.003; CI_95%: 1.002–1.04).

Conclusion

Urban cases were concentrated in the capital and rural cases in a specific ecoregion. The major drivers identified in this study were related to environmental and production processes that are permanent features of the state. This study contributes to the basic knowledge on leptospirosis distribution and drivers in the state and encourages a comprehensive approach to address the disease in the animal-human-ecosystem interface.     

Modulation of nitrate reductase activity by photosynthetic electron transport chain and nitric oxide balance in the red macroalga Gracilaria chilensis (Gracilariales, Rhodophyta)

Nitrate reductase (NR), a key enzyme in nitrogen metabolism, has been implicated in the production of nitric oxide (NO) in plants. The effect of photosynthetic electron transport chain inhibitors and NO scavengers or donors on NR activity of Gracilaria chilensis was studied under experimental laboratory conditions. Effective quantum yield (Φ _PSII) and NR activity were significantly diminished by 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, two photosynthetic electron flux inhibitors of photosystem (PS) II and PSI, respectively, but not by diphenyleneiodonium, a NADPH oxidase inhibitor, indicating a direct dependence of NR activity on the PSII and PSI electron flux. Nitrate reductase activity was sensitive to a decrease or increase of NO levels when NO scavenger (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) and NO donor (sodium nitroprusside) were added. Moreover, the addition of 8Br-cGMP, a secondary signal molecule, stimulated NR activity. These results evidence a modulation of the photosynthetic electron transport chain and NO balance on G. chilensis NR activity. This association could be linked to the crucial tight modulation of nitrogen assimilation and carbon metabolism to guarantee nitrite incorporation into organic compounds and to avoid toxicity by nitrite, reactive oxygen species, or nitric oxide in the cells. Nitric oxide showed to be an important signaling molecule regulating NR activity and cGMP could participate as secondary messenger on this regulation by phosphorylation and desphosphorylation processes.     

Complete characterization of wheat–alien metaphase I pairing in interspecific hybrids between durum wheat (Triticum turgidum L.) and jointed goatgrass (Aegilops cylindrica Host)

The pattern of homoeologous metaphase I (MI) pairing has been fully characterized in durum wheat × Aegilops cylindrica hybrids (2n = 4x = 28, ABC^cD^c) by an in situ hybridization procedure that has permitted individual discrimination of every wheat and wild constituent genome. One of the three hybrid genotypes examined carried the ph1c mutation. In all cases, MI associations between chromosomes of both species represented around two-third of total. Main results from the analysis are as follows (a) the A genome chromosomes are involved in wheat–wild MI pairing more frequently than the B genome partners, irrespective of the alien genome considered; (b) both durum wheat genomes pair preferentially with the D^c genome of jointed goatgrass. These findings are discussed in relation to the potential of genetic transference between wheat crops and this weedy relative. It can also be highlighted that inactivation of Ph1 provoked a relatively higher promotion of MI associations involving B genome.     

Immature and mature human astrovirus: structure, conformational changes, and similarities to hepatitis e virus

Human astroviruses (HAstVs) are a major cause of gastroenteritis. HAstV assembles from the structural protein VP90 and undergoes a cascade of proteolytic cleavages. Cleavage to VP70 is required for release of immature particles from cells, and subsequent cleavage by trypsin confers infectivity. We used electron cryomicroscopy and icosahedral image analysis to determine the first experimentally derived, three-dimensional structures of an immature VP70 virion and a fully proteolyzed, infectious virion. Both particles display T = 3 icosahedral symmetry and nearly identical solid capsid shells with diameters of ~ 350 Å. Globular spikes emanate from the capsid surface, yielding an overall diameter of ~ 440 Å. While the immature particles display 90 dimeric spikes, the mature capsid only displays 30 spikes, located on the icosahedral 2-fold axes. Loss of the 60 peripentonal spikes likely plays an important role in viral infectivity. In addition, immature HAstV bears a striking resemblance to the structure of hepatitis E virus (HEV)-like particles, as previously predicted from structural similarity of the crystal structure of the astrovirus spike domain with the HEV P-domain [Dong, J., Dong, L., Méndez, E. &; Tao, Y. (2011). Crystal structure of the human astrovirus capsid spike. Proc. Natl. Acad. Sci. USA 108, 12681–12686]. Similarities between their capsid shells and dimeric spikes and between the sequences of their capsid proteins suggest that these viral families are phylogenetically related and may share common assembly and activation mechanisms.