Polymorphisms of the porcine dopamine beta-hydroxylase gene and their relation to reproduction and piglet survivability in an Iberian x Meishan F2 intercross

The goals of this study were to sequence and physically map the porcine dopaminebeta-hydroxylase (DBH) gene, as well as to perform an association study between polymorphisms of this gene and the reproductive performance and piglet survivability of F(2) pigs from an Iberian x Meishan cross. The porcine DBH gene was positioned by RH mapping near the telomere of chromosome 1q2.13, close to markers SSC10D08 and SW1301. Sequencing of DBH cDNAs from 10 pigs revealed the existence of six nucleotide polymorphisms, two of which led to non-synonymous amino acid substitutions within exon 3 at positions 463A>G and 616A>G that corresponded to Thr155Ala and Lys206Glu respectively. Three haplotypes segregated in an Iberian x Meishan population: DBH(X) (A(436)-A(616)), DBH(Y) (A(436)-G(616)) and DBH(Z) (G(436)-G(616)). The DBH haplotypes significantly affected rectal temperatures 1 h after birth (P = 0.002) and have a suggestive effect on the time to first colostrum intake (P = 0.019) and on birth weight (P = 0.019).     

Specific hypomethylation of DNA is induced by heavy metals in white clover and industrial hemp

The present study was to assess the effect of heavy metal stress on the DNA methylation of a metal-sensitive plant, Trifolium repens L. and of a metal-tolerant plant, Cannabis sativa L. The changes in the level of 5-methylcytosine (5mC) in the root DNA of plants grown on soils contaminated with different concentrations of Ni²⁺, Cd²⁺ and Cr⁶⁺ compared with that of untreated plants, were determined by immunolabelling with a monoclonal antibody, using the Slot-Blot technique. Results showed that DNA of hemp control plants was about three times more methylated than clover DNA, for the same amount of root DNA. Heavy metal treatments induced a global dose-dependent decrease of 5mC content, both in hemp and clover, ranging from 20 to 40%. Changes in methylation pattern of 5'-CCGG-3' containing sequences were investigated by methylation-sensitive amplification polymorphism (MSAP) technique. Control plants of the same species showed a very similar pattern, suggesting that, in normal condition, methylation involves precise sites. Heavy metals induced DNA methylation changes mainly related to hypomethylation events. These variations were not randomly directed but involved specific DNA sequences, since the detected polymorphisms were the same in all the plants analysed for each treatment.     

Interspecies transmission of simian foamy virus in a natural predator-prey system

Simian foamy viruses (SFV) are ancient retroviruses of primates and have coevolved with their host species for as many as 30 million years. Although humans are not naturally infected with foamy virus, infection is occasionally acquired through interspecies transmission from nonhuman primates. We show that interspecies transmissions occur in a natural hunter-prey system, i.e., between wild chimpanzees and colobus monkeys, both of which harbor their own species-specific strains of SFV. Chimpanzees infected with chimpanzee SFV strains were shown to be coinfected with SFV from colobus monkeys, indicating that apes are susceptible to SFV superinfection, including highly divergent strains from other primate species.     

Type 1 Diabetes Prevention in NOD Mice by Targeting DPPIV/CD26 Is Associated with Changes in CD8+T Effector Memory Subset

CD26 is a T cell activation marker consisting in a type II transmembrane glycoprotein with dipeptidyl peptidase IV (DPPIV) activity in its extracellular domain. It has been described that DPPIV inhibition delays the onset of type 1 diabetes and reverses the disease in non-obese diabetic (NOD) mice. The aim of the present study was to assess the effect of MK626, a DPPIV inhibitor, in type 1 diabetes incidence and in T lymphocyte subsets at central and peripheral compartments. Pre-diabetic NOD mice were treated with MK626. Diabetes incidence, insulitis score, and phenotyping of T lymphocytes in the thymus, spleen and pancreatic lymph nodes were determined after 4 and 6 weeks of treatment, as well as alterations in the expression of genes encoding β-cell autoantigens in the islets. The effect of MK626 was also assessed in two in vitro assays to determine proliferative and immunosuppressive effects. Results show that MK626 treatment reduces type 1 diabetes incidence and after 6 weeks of treatment reduces insulitis. No differences were observed in the percentage of T lymphocyte subsets from central and peripheral compartments between treated and control mice. MK626 increased the expression of CD26 in CD8⁺ T effector memory (T_EM) from spleen and pancreatic lymph nodes and in CD8⁺ T cells from islet infiltration. CD8⁺T_EM cells showed an increased proliferation rate and cytokine secretion in the presence of MK626. Moreover, the combination of CD8⁺ T_EM cells and MK626 induces an immunosuppressive response. In conclusion, treatment with the DPPIV inhibitor MK626 prevents experimental type 1 diabetes in association to increase expression of CD26 in the CD8⁺ T_EM lymphocyte subset. In vitro assays suggest an immunoregulatory role of CD8⁺ T_EM cells that may be involved in the protection against autoimmunity to β pancreatic islets associated to DPPIV inhibitor treatment.     

The toxic effect of fluoride on MG-63 osteoblast cells is also dependent on the production of nitric oxide

Some soda-lime-phospho-silicate glasses, such as Hench's Bioglass(?) 45S5, form bone-like apatite on their surface when bound to living bone. To improve their osteointegration for clinical purposes, the fluoride insertion in their structure has been proposed, but we recently showed that fluoride causes oxidative damage in human MG-63 osteoblasts, via inhibition of pentose phosphate oxidative pathway (PPP) and its key enzyme glucose 6-phosphate dehydrogenase (G6PD). In the same cells we have now investigated the role of nitric oxide (NO) in these effects. Fluoride-containing bioactive glasses and NaF caused, as expected, release of lactate dehydrogenase in the extracellular medium, accumulation of intracellular malonyldialdehyde, inhibition of PPP and G6PD: we have now observed that these effects were significantly reverted not only by superoxide dismutase (SOD) plus catalase (scavengers of reactive oxygen species), but also by N-monomethyl l-arginine (l-NMMA, a NOS inhibitor) and 2-phenyl-4,4,5,5,-tetramethylimidazoline-1oxyl 3-oxide (PTIO, a NO scavenger). Moreover the two highest concentrations of both fluoride-containing bioglasses and NaF caused increase of nitrite (a stable derivative of NO) levels in the culture supernatant, which was inhibited by l-NMMA, erythrocytes, PTIO and SOD/catalase, and increase of intracellular NO synthase (NOS) activity. The incubation with bioglasses or NaF increased also the phosphorylation of Ser(1177) in the endothelial NOS isoform. Furthermore, the NO donor spermine NONOate was able to inhibit G6PD activity in vitro, and this effect was partly reverted by PTIO. Therefore our results suggest that most cytotoxic effects of fluoride are mediated by the production of NO: reactive oxygen species are important, causing NOS phosphorylation. We also observed, for the first time, that Tempol, but not SOD/catalase, besides inhibiting the oxidative stress induced by fluoride, also scavenges fluoride ions. For this reason it is not a selective inhibitor of the oxidative effects of fluoride.     

Efficacy of a combination therapy targeting CDK4/6 and autophagy in a mouse xenograft model of t(8;21) acute myeloid leukemia

One of the most frequent cytogenetic abnormalities in acute myeloid leukemia (AML) is t(8;21). Although patients with t(8;21) AML have a more favorable prognosis than other cytogenetic subgroups, relapse is still common and novel therapeutic approaches are needed. A recent study showed that t(8;21) AML is characterized by CCND2 deregulation and that co-inhibition of CDK4/6 and autophagy induces apoptosis in t(8;21) AML cells. In this study, we examined the in vivo effects of co-inhibiting CDK4/6 and autophagy. We used a mouse model in which t(8;21)-positive Kasumi-1 cells were subcutaneously inoculated into NOD/Shi-scid IL2Rg^null mice. The mice were treated with the autophagy inhibitor chloroquine (CQ), a CDK4/6 inhibitor (either abemaciclib or palbociclib), or a CDK4/6 inhibitor plus CQ. After 20 days of treatment, tumor volume was measured, and immunostaining and transmission electron microscopy observations were performed. There was no change in tumor growth in CQ-treated mice. However, mice treated with a CDK4/6 inhibitor plus CQ had significantly less tumor growth than mice treated with a CDK4/6 inhibitor alone. CDK4/6 inhibitor treatment increased the formation of autophagosomes. The number of single-strand DNA-positive (apoptotic) cells was significantly higher in the tumors of mice treated with a CDK4/6 inhibitor plus CQ than in mice treated with either CQ or a CDK4/6 inhibitor. These results show that CDK4/6 inhibition induces autophagy, and that co-inhibition of CDK4/6 and autophagy induces apoptosis in t(8;21) AML cells in vivo. The results suggest that inhibiting CDK4/6 and autophagy could be a novel and promising therapeutic strategy in t(8;21) AML.     

中亚热带喀斯特常绿落叶阔叶混交林典型树种的木质部解剖与功能特征分析

树木木质部主要由导管、纤维和薄壁组织组成, 分别具有运输、支撑和贮存的生理功能。由于木质部空间限制, 一种组织比例的增加会导致其他组织比例的降低, 因而可能表现出权衡关系。分析木质部组织比例和权衡关系有助于了解植物的生理生态适应性。该研究选择中亚热带喀斯特常绿落叶阔叶混交林21种典型树种(10种落叶树种, 11种常绿树种), 测定枝条木质部各组织比例, 计算水力相关指标并分析性状之间的相关性。结果表明: (1)与全球木质部解剖数据对比分析, 喀斯特树种木质部趋向具有较高比例的薄壁组织; (2)喀斯特树种导管组织比例与薄壁和纤维组织比例之间没有显著的相关性, 但是薄壁和纤维组织比例之间有显著的权衡关系; (3)常绿和落叶树种的木质部水力运输安全性(导管壁加固系数)和效率性(理论导水率)均具有显著的权衡关系, 但是这两个类群线性回归的截距存在显著差异, 即在相同的理论导水率条件下, 落叶树种比常绿树种具有较高的导管壁加固系数(安全性), 可能与常绿树种具有更多的轴向薄壁组织有关。喀斯特树种木质部解剖特征表明薄壁组织的贮存功能对喀斯特树种(尤其是常绿树种)的干旱适应具有重要作用。     

Genetic determinism for within-litter birth weight variation and its relationship with litter weight and litter size in the Ripollesa ewe breed

Birth weight plays a central role in lamb survival and growth, and the knowledge of its genetic determinism has become essential in worldwide selection programmes. Within this context, within-litter birth weight variation (BWV) has been suggested as an attractive trait to homogenise litters in prolific species, although it has not been analysed in sheep. The objective of this study was to ascertain whether maternal additive genetic variance exists for BWV in Ripollesa ewes, and to study its genetic, permanent environmental and residual relationships with litter weight (LW) and litter size (LS) at birth. Data were recorded in the Ripollesa experimental flock of the Universitat Autònoma of Barcelona, between 1986 and 2005, and included 1 662 litters from 380 ewes, with 712 records of BWV and 1 530 records of LW. Traits were analysed with a multivariate animal model solved through Bayesian methodologies, and with a threshold characterisation of LS. Additionally, the effect of BWV on lamb survival was studied. Additive genetic variance was observed for BWV (h² = 0.061), as well as for LW (h² = 0.200) and LS (h² = 0.141). Nevertheless, genetic correlations among those traits were not substantial (BWV and LW = 0.151; BWV and LS = − 0.219; LW and LS = − 0.320) and suffered from a high degree of uncertainly, with the null correlation included within the highest posterior interval at 95%. Within-litter birth weight variation and LS showed a negative and large permanent environmental correlation ( − 0.872), and LW and LS were negatively correlated due to residual ( − 0.762) and permanent environmental ( − 0.449) random sources of variation. Within-litter birth weight variation influenced lamb mortality during the first 7 days of life (P < 0.05), increasing and decreasing survivability in heavier and lighter littermates, respectively. Nevertheless, stillbirths and lambs died after the 1st week of life were not affected by BWV (P>0.05). The low heritability found indicates that slow genetic progress may be expected from selecting for BWV. Close to zero genetic correlations suggest that this selection will probably not affect LS and LW, although some significant permanent and residual correlations must be taken into account. Further studies are needed to understand better the genetic architecture among these three reproductive traits.