Molecular characterization, expression and localization of a peroxiredoxin from the sheep scab mite, Psoroptes ovis

The sheep scab mite, Psoroptes ovis, induces an intensely pruritic exudative dermatitis which is responsible for restlessness, loss of appetite and weight loss. Within the first 24 h of infection, there is a rapid inflammatory influx of eosinophils and apoptosis of the keratinocytes at the site of infection. The former cell type is capable of a sustained respiratory burst, toxic products of which may directly damage the mite and also contribute to lesion formation. Analysis of a P. ovis expressed sequence tag (EST) database identified a number of antioxidant enzyme-encoding sequences, including peroxiredoxin (thioredoxin peroxidase EC 1.11.1.15), all of which may help the mite endure the potentially toxic skin environment. A full length sequence encoding Po-TPx, a protein of 206 amino acids which showed high homology to a peroxiredoxin from the salivary gland of the tick Ixodes scapularis, was amplified from P. ovis cDNA. Recombinant Po-TPx was expressed in bacteria and antiserum to this protein was used to localize native Po-TPx in mite sections. Peroxiredoxin was localized, amongst other sites, to a subpharyngeal region in mite sections. The recombinant protein was recognized by sera from sheep infested with the mite suggesting that it may be secreted or excreted by the mite and interact with the host immune response

The Candida albicans Histone Acetyltransferase Hat1 Regulates Stress Resistance and Virulence via Distinct Chromatin Assembly Pathways

Human fungal pathogens like Candida albicans respond to host immune surveillance by rapidly adapting their transcriptional programs. Chromatin assembly factors are involved in the regulation of stress genes by modulating the histone density at these loci. Here, we report a novel role for the chromatin assembly-associated histone acetyltransferase complex NuB4 in regulating oxidative stress resistance, antifungal drug tolerance and virulence in C. albicans. Strikingly, depletion of the NuB4 catalytic subunit, the histone acetyltransferase Hat1, markedly increases resistance to oxidative stress and tolerance to azole antifungals. Hydrogen peroxide resistance in cells lacking Hat1 results from higher induction rates of oxidative stress gene expression, accompanied by reduced histone density as well as subsequent increased RNA polymerase recruitment. Furthermore, hat1Delta/Delta cells, despite showing growth defects in vitro, display reduced susceptibility to reactive oxygen-mediated killing by innate immune cells. Thus, clearance from infected mice is delayed although cells lacking Hat1 are severely compromised in killing the host. Interestingly, increased oxidative stress resistance and azole tolerance are phenocopied by the loss of histone chaperone complexes CAF-1 and HIR, respectively, suggesting a central role for NuB4 in the delivery of histones destined for chromatin assembly via distinct pathways. Remarkably, the oxidative stress phenotype of hat1Delta/Delta cells is a species-specific trait only found in C. albicans and members of the CTG clade. The reduced azole susceptibility appears to be conserved in a wider range of fungi. Thus, our work demonstrates how highly conserved chromatin assembly pathways can acquire new functions in pathogenic fungi during coevolution with the host

Avaliação e mapeamento de pastagens com diferentes níveis de degradação a partir de classificação digital de imagens sentinel-2, por meio do algoritmo random forest: estudo de caso de Valença/RJ e arredores.

O presente trabalho objetivou desenvolver uma metodologia de avaliação e mapeamento de pastagens com diferentes níveis de degradação, com base em técnicas de Sensoriamento Remoto. Utilizou-se imagens Sentinel-2, índices de vegetação, texturas GLCM e amostras de campo (peso e altura da biomassa das pastagens). O processamento das imagens digitais foi realizado no R e no Google Earth Engine usando o algoritmo random forest. No R, obteve-se informações sobre as imagens mais importantes; e no Google Earth Engine, realizou-se o processamento da série temporal principal. O índice de vegetação NCI foi a imagem mais importante, apresentando correlação de R2 = 0,722 com o peso da biomassa. Os resultados revelaram que na área de estudo tem-se: N1 (52.72%), N2N3 (32.56%) e N4 (14.72%). As acurácias alcançadas foram as seguintes: Acurácia Global = 0,93; Kappa = 0,89; e F-score (N1 = 0,97, N2N3 = 0,93, N4 = 0,88)

Mechanistic illustration: How newly‐formed blood vessels stopped by the mineral blocks of bone substitutes can be avoided by using innovative combined therapeutics

One major limitation for the vascularization of bone substitutes used for filling is the presence of mineral blocks. The newly-formed blood vessels are stopped or have to circumvent the mineral blocks, resulting in inefficient delivery of oxygen and nutrients to the implant. This leads to necrosis within the implant and to poor engraftment of the bone substitute. The aim of the present study is to provide a bone substitute currently used in the clinic with suitably guided vascularization properties. This therapeutic hybrid bone filling, containing a mineral and a polymeric component, is fortified with pro-angiogenic smart nano-therapeutics that allow the release of angiogenic molecules. Our data showed that the improved vasculature within the implant promoted new bone formation and that the newly-formed bone swapped the mineral blocks of the bone substitutes much more efficiently than in non-functionalized bone substitutes. Therefore, we demonstrated that our therapeutic bone substitute is an advanced therapeutical medicinal product, with great potential to recuperate and guide vascularization that is stopped by mineral blocks, and can improve the regeneration of critical-sized bone defects. We have also elucidated the mechanism to understand how the newly-formed vessels can no longer encounter mineral blocks and pursue their course of vasculature, giving our advanced therapeutical bone filling great potential to be used in many applications, by combining filling and nano-regenerative medicine that currently fall short because of problems related to the lack of oxygen and nutrients

Avaliação do impacto das amostras de treinamento na acurácia da classificação random forest dos sistemas integrados de produção agropecuária.

Ao conduzir uma classificação supervisionada com algoritmos de aprendizado de máquina, como o Random Forest, a estratégia de balanceamento das amostras é fundamental, pois impacta diretamente nos resultados. Estes classificadores são sensíveis às proporções das amostras de treinamento das diferentes classes. Compreender como estes fatores influenciam na classificação de áreas de produção agropecuária, sobretudo de sistemas minoritários e complexos como o iLP (Integração Lavoura-Pecuária) são de extrema importância para contribuir com metodologias de monitoramento. Para avaliar o impacto do balanceamento, foram testados três grupos de dados de aprendizagem do Random Forest: (i) Bset01: dados balanceados entre três classes prioritárias no estado do Mato Grosso; (ii) Bset02: dados desbalanceados com as proporções refletindo a realidade de campo e (iii) Bset03: superestimando a classe rara iLP. Os melhores valores de fscore da classe iLP foram para Bset01 (0,81) e Bset02 (0,83), com um erro de comissão mais alto para Bset01, sugerindo uma melhor performance do Bset02