Sperm protamine deficiency correlates with sperm DNA damage in Bos indicus bulls

The primary purpose of spermatozoa is to deliver the paternal DNA to the oocyte at fertilization. During the complex events of fertilization, if the spermatozoon penetrating the oocyte contains compromised or damaged sperm chromatin, the subsequent progression of embryogenesis and foetal development may be affected. Variation in sperm DNA damage and protamine content in ejaculated spermatozoa was reported in the cattle, with potential consequences to bull fertility. Protamines are sperm-specific nuclear proteins that are essential to packaging of the condensed paternal genome in spermatozoa. Sperm DNA damage is thought to be repaired during the process of protamination. This study investigates the potential correlation between sperm protamine content, sperm DNA damage and the subsequent relationships between sperm chromatin and commonly measured reproductive phenotypes. Bos indicus sperm samples (n = 133) were assessed by two flow cytometric methods: the sperm chromatin structure assay (SCSA) and an optimized sperm protamine deficiency assay (SPDA). To verify the SPDA assay for bovine sperm protamine content, samples collected from testis, caput and cauda epididymidis were analyzed. As expected, mature spermatozoa in the cauda epididymidis had higher protamine content when compared with sperm samples from testis and caput epididymidis (p < 0.01). The DNA fragmentation index (DFI), determined by SCSA, was positively correlated (r = 0.33 ± 0.08, p < 0.05) with the percentage of spermatozoa that showed low protamine content using SPDA. Also, DFI was negatively correlated (r = -0.21 ± 0.09, p < 0.05) with the percentage of spermatozoa with high protamine content. Larger scrotal circumference contributes to higher sperm protamine content and lower content of sperm DNA damage (p < 0.05). In conclusion, sperm protamine content and sperm DNA damage are closely associated. Protamine deficiency is likely to be one of the contributing factors to DNA instability and damage, which can affect bull fertility. © 2014 American Society of Andrology and European Academy of Andrology

TNFR2 unlocks a RIPK1 kinase activity-dependent mode of proinflammatory TNFR1 signaling

TNF is not only a major effector molecule of PAMP/DAMP-activated macrophages, but also regulates macrophage function and viability. We recently demonstrated that TNFR2 triggers necroptosis in macrophages with compromised caspase activity by two cooperating mechanisms: induction of endogenous TNF with subsequent stimulation of TNFR1 and depletion of cytosolic TRAF2-cIAP complexes. Here we show that TNFR2 activation in caspase-inhibited macrophages results in the production of endogenous TNF and TNFR1 stimulation followed by upregulation of A20, TRAF1, IL-6, and IL-1 beta. Surprisingly, TNFR1-mediated induction of IL-6 and IL-1 beta was clearly evident in response to TNFR2 stimulation but occurred not or only weakly in macrophages selectively and directly stimulated via TNFR1. Moreover, TNFR2-induced TNFR1-mediated gene induction was largely inhibited by necrostatin-1, whereas upregulation of A20 and TRAF1 by direct and exclusive stimulation of TNFR1 remained unaffected by this compound. Thus, treatment with TNFR2/ZVAD enables TNFR1 in macrophages to stimulate gene induction via a pathway requiring RIPK1 kinase activity. TNFR2/ZVAD-induced production of IL-6 and IL-1 beta was largely blocked in necroptosis-resistant MLKL- and RIPK3-deficient macrophages, whereas induction of A20 and TRAF1 remained unaffected. In sum, our results show that in caspase-inhibited macrophages TNFR2 not only triggers TNF/TNFR1-mediated necroptosis but also TNF/TNFR1-mediated RIPK3/MLKL-dependent and -independent gene induction

Phenetic studies on randomly amplified polymorphic DNA-polymerase chain reaction-variability of four geographical populations of Lutzomyia whitmani (Diptera: Psychodidae) in Brazil Estudos fenéticos de variabilidade de polimorfismos de DNA amplificados ao acaso pela reação em cadeia da polimerase em quatro populações geográficas de Lutzomyia whitmani (Diptera: Psychodidade) no Brasil

Previous evaluation of the genetic variability of four biogeographical populations of Lutzomyia whitmani from known foci of cutaneous leishmaniasis in Brazil demonstrated two main spatial clusters: Corte de Pedra-BA, Ilhéus-BA and Serra de Baturité-CE in the first cluster, and Martinho Campos-MG in the second. Further analysis showed a high degree of homogeneity in Corte de Pedra population but not in the others, which presented a significant percentage of specimens displaced from their phenon of origin (discrepant individuals). In the present work we analyzed the frequencies of association coefficients in the matrixes of similarity per population of Lutzomyia whitmani from both sexes and the general phenograms obtained, in a more detailed study of those discrepant specimens. Populational stability was observed for Corte de Pedra population, whereas the three remaining populations showed varying degrees of heterogeneity and different displacements according to sex. Our results strongly suggested the existence of a genetic flow between the lineages North-South/North-East and Ilhéus/Serra do Baturité of Lutzomyia whitmani.<br>Uma avaliação prévia da variabilidade genética de quatro populações biogeográficas de Lutzomyia whitmani oriundas de focus conhecidos de leishmaniose cutânea no Brasil, evidenciou 2 agrupamentos espaciais principais: Corte de Pedra (BA), Ilhéus (BA) e Serra de Baturité (CE) no primeiro grupo, e Martinho Campos (MG) em um segundo. O aprofundamento da análise acusou um alto grau de homogeneidade na população de Corte de Pedra mas não nas outras, nas quais uma porcentagem significativa de espécimens deslocou-se do seu feno de origem (indivíduos discrepantes). Neste trabalho analisamos as freqüências dos coeficientes de associação nas matrizes de similaridade por população de Lutzomyia whitmani, de ambos os sexos, e o fenograma geral obtido, em um estudo mais detalhado daqueles espécimens discrepantes. Para Corte de Pedra foi observada estabilidade populacional, enquanto as outras três populações restantes mostraram graus de heterogeneidade variáveis e deslocamentos distintos, de acordo com o sexo dos indivíduos. Nossos resultados sugerem fortemente a existência de um fluxo genético entre as linhagens Norte-Sul/Norte-Leste e Ilhéus/Serra do Baturité de Lutzomyia whitmani