The Impact of Magnesium on Isometric Twitch Parameters and Resting Membrane Potential of the Skeletal Muscle in Diabetic Rats

To present the relationship between oral magnesium supplementation, blood glucose, and changes in isometric twitch parameters, resting membrane potential (RMP), in the gastrocnemius muscle in diabetic rats. Sixty rats were used in this study. The rats were divided into four groups: control (drinking tap water, Group I, n = 15), control with treated with magnesium sulfate (10 g/L) (Group II, n = 15), diabetic (Group III, n = 15), and diabetic with treated with magnesium sulfate (10 g/L) (Group IV, n = 15). In Group II and IV, the level of plasma magnesium was increased comparing to those of the control group (p < 0.05). Isometric twitch tensions were decreased significantly in the Group III, but Group IV isometric twitch tensions were increased significantly. Group IV RMP values were close to the Group I. Hyperglycemia decreases gastrocnemius muscle isometric twitch tension and increases RMP in diabetic rats. Magnesium treatment can prevent these diabetic complications.     

Genomic divergence of zebu and taurine cattle identified through high-density SNP genotyping

Background

Natural selection has molded evolution across all taxa. At an arguable date of around 330,000 years ago there were already at least two different types of cattle that became ancestors of nearly all modern cattle, the Bos taurus taurus more adapted to temperate climates and the tropically adapted Bos taurus indicus. After domestication, human selection exponentially intensified these differences. To better understand the genetic differences between these subspecies and detect genomic regions potentially under divergent selection, animals from the International Bovine HapMap Experiment were genotyped for over 770,000 SNP across the genome and compared using smoothed F_ST. The taurine sample was represented by ten breeds and the contrasting zebu cohort by three breeds.

Results

Each cattle group evidenced similar numbers of polymorphic markers well distributed across the genome. Principal components analyses and unsupervised clustering confirmed the well-characterized main division of domestic cattle. The top 1% smoothed F_ST, potentially associated to positive selection, contained 48 genomic regions across 17 chromosomes. Nearly half of the top F_ST signals (n = 22) were previously detected using a lower density SNP assay. Amongst the strongest signals were the BTA7:~50 Mb and BTA14:~25 Mb; both regions harboring candidate genes and different patterns of linkage disequilibrium that potentially represent intrinsic differences between cattle types. The bottom 1% of the smoothed F_ST values, potentially associated to balancing selection, included 24 regions across 13 chromosomes. These regions often overlap with copy number variants, including the highly variable region at BTA23:~24 Mb that harbors a large number of MHC genes. Under these regions, 318 unique Ensembl genes are annotated with a significant overrepresentation of immune related pathways.

Conclusions

Genomic regions that are potentially linked to purifying or balancing selection processes in domestic cattle were identified. These regions are of particular interest to understand the natural and human selective pressures to which these subspecies were exposed to and how the genetic background of these populations evolved in response to environmental challenges and human manipulation.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-14-876) contains supplementary material, which is available to authorized users.     

Inhibition of Bovine Kidney Low Molecular Mass Phosphotyrosine Protein Phosphatase by Uric Acid

Uric acid inhibited 50% of the activity of bovine kidney low molecular mass phosphotyrosine protein phosphatase at concentrations of 1.0, 0.4, 1.3, and 0.2 mM, respectively for p -nitrophenyl phosphate (p -NPP), flavine mononucleotide, β -naphthyl phosphate and tyrosine phosphate (Tyr-P) as substrates. The mixed type inhibition of p -NPP hydrolysis was fully reversible, with K ic and K iu values of 0.4 and 1.1 mM, respectively; the inhibition by uric acid shifted the pH optimum from 5.0 to 6.5. When Tyr-P was the substrate, competitive inhibition was observed with a K i value of 0.05 mM. Inhibition studies by uric acid in the presence of thiol compounds, and preincubation studies in the presence of inorganic phosphate suggest that the interaction of uric acid with the enzyme occurred at the active site, but did not involve SH residues, and that the mechanism of inhibition depended on the structure of the substrates.     

Synthesis of dimeric phenol derivatives and determination of in vitro antioxidant and radical scavenging activities

In this study, di(2,6-dimethylphenol) (Di-DMP), di(2,6-diisopropylphenol) (Di-DIP, dipropofol) and di(2,6-di-t-butylphenol) (Di-DTP) were synthesized by the reaction of monomeric phenol derivatives with catalytic CuCl(OH). TMEDA and Na₂S₂O₄. Their antioxidant capacity and radical scavenging activity were examined using different in vitro methodologies such as 1,1-diphenyl-2-picryl-hydrazyl (DPPH·) free radical scavenging, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, total antioxidant activity by ferric thiocyanate, total reducing power by potassium ferricyanide reduction method, superoxide anion radical scavenging, hydrogen peroxide scavenging and ferrous ions chelating activities.     

Synthesis and preliminary evaluation of new ursolic and oleanolic acids derivatives as antileishmanial agents

A series of new ursolic and oleanolic acids derivatives was synthesized via ursolic or oleanolic acids, previously extracted from South American Ilex species. These new compounds were tested for in vitro antiparasitic activity on Leishmania amazonensis and Leishmania infantum strains. Some of these compounds showed activity against the promastigote forms of L. amazonensis or L. infantum, with IC₅₀ ranging from 5 to 12 μM. As expected, most of the compounds showed a significant level of cytotoxicity against monocytes (IC₅₀ = 2-50 μM). From a structure-activity relationships point of view, these pharmacological results enlightened mainly the importance of an acetylation at position 3 of the oleanolic acid skeleton in the activity against the L. amazonensis strain, and of a bis-(3-aminopropyl)piperazine moiety on the carboxylic function of ursolic acid against the L. infantum strain.     

New data on the Dyrosauridae (Crocodylomorpha) from the Paleocene of Togo

Following our fieldwork in Paleogene deposits of Togo, we herein report cranial as well as postcranial elements belonging to the family Dyrosauridae. This assemblage is dated to the Late Paleocene (Thanetian) from two quarries in southern Togo. The specimens include a partial skull presenting two large supratemporal fossae and a massive occipital condyle; long and slender isolated teeth; amphicoelous vertebrae including several articulated ones; and two osteoderms devoid of carina. The morphology of the partial skull reveals similarities with some African longirostrine forms such as Rhabdognathus spp., although this attribution cannot be confirmed. Longirostrine forms, known in the late Paleocene and early Eocene of the Iullemmeden basin (Nigeria, Niger, Mali, Algeria) and in the phosphates of Morocco and Tunisia, is only represented in Thanetian levels in Togo. Different palaeoenvironmental settings seem to have characterized the various African basins during the lower Eocene, with consequences for the geographic distribution of dyrosaurids. These dyrosaurid remains confirm the presence of the family in Togo during the Paleocene and underline the fossiliferous potential of the coastal sedimentary basin in Togo and in the bay of Benin.     

Trichinella spiralis infection ameliorated diet-induced obesity model in mice

Obesity is an increasingly prevalent disease worldwide, and genetic and environmental factors are known to regulate the development of obesity and associated metabolic diseases. Emerging studies indicate that innate and adaptive immune cell responses in adipose tissue play critical roles in the regulation of metabolic homeostasis. Parasitic helminths are the strongest natural inducers of type 2 inflammatory responses, and several studies have revealed that helminth infections inversely correlate with metabolic syndrome. Hence, this study investigated whether helminth infections could have preventative effects on high fat diet-induced obesity. Female C57BL/6 mice were maintained on either a low fat diet (LFD, 10% fat) or a high fat diet (HFD, 60% fat) for 6 weeks after Trichinella spiralis infection. The mice were randomly divided into four groups and were fed a normal diet, LFD, LFD after T. spiralis infection (Inf + LFD), a high fat diet (HFD), or HFD after T. spiralis infection (HFD + inf). All groups were assayed for body weight, food efficiency ratio (FER), total body weight gain (g)/total food intake amount (g) fat weight, and blood biochemical parameters. Our data indicate that the HFD + inf group significantly reduced body weight gain, fat mass, total cholesterol, and FER. Analysis of immune cell composition by flow cytometry revealed that T. spiralis promoted strong decreases in proinflammatory adipose macrophages (F4/80⁺CD11c⁺) and T cells. The alterations in microbiota from fecal samples of mice were analyzed, which showed that T. spiralis infection decreased the ratio of Firmicutes to Bacteriodetes, thereby restoring the previously increased ratio of Firmicutes to Bacteriodetes in HFD-fed mice. Moreover, elimination of T. spiralis retained the protective effects in the HFD-fed obese mice whereas flubendazole (FLBZ) treatment increased levels of the families Lachnospiraceae and Ruminococcaceae. In summary, we provided novel data suggesting that helminth infection protects against obesity and the protection was closely related to M2 macrophage proliferation, an inhibiting proinflammatory response. In addition, it alters the microbiota in the gut.     

Post-weaning protein malnutrition induces myocardial dysfunction associated with oxidative stress and altered calcium handling proteins in adult rats

Journal of Physiology and Biochemistry - Hypercaloric low-protein diet may lead to a state of malnutrition found in the low-income population of Northeastern Brazil. Although malnutrition during...     

青藏高原植被生长季NDVI时空变化与影响因素

青藏高原是中国乃至亚洲的生态屏障,研究其植被对气候变化的响应对区域生态保护具有重要的现实意义。基于MOD09A1数据反演的生长季归一化植被指数(NDVI),分析2001—2018年青藏高原植被生长季NDVI时空特征和变化趋势,结合气象站点数据阐释NDVI与气候因子的关系。结果表明: 研究期间,青藏高原植被生长季NDVI呈缓慢上升趋势,不同气候区生长季NDVI年际变化差异明显,NDVI值波动幅度表现为高原湿润气候区>半湿润气候区>半干旱气候区>干旱气候区。青藏高原湿润气候区、半湿润气候区、干旱气候区、半干旱气候区NDVI显著升高和降低面积占比分别为1.4%和1.9%、4.9%和1.5%、16.4%和0.8%、7.0%和2.0%,干旱和半干旱气候区NDVI升高面积占比明显大于湿润和半湿润气候区。气温是影响湿润气候区和半湿润气候区NDVI变化的主导因子,而在干旱气候区,降水对NDVI的影响明显强于其他气候因子。气温对整个青藏高原植被生长季NDVI的驱动作用强于降水和相对湿度。     

慢性阻塞性肺疾病急性加重期患者咽部菌群与免疫指标的相关性

目的探讨慢性阻塞性肺疾病(COPD)急性加重期患者咽部菌群与免疫指标的相关性,为该类患者的治疗提供参考。方法选取2016年6月至2019年8月期间于我院就诊的125例COPD患者作为研究对象,其中急性加重期60例(急性加重组),缓解期65例(缓解组)。选取同期于我院进行健康体检者60例作为对照组。比较3组对象咽部菌群检出情况和CD3~+细胞、CD4~+细胞及CD4~+/CD8~+水平,并进行Spearman相关性分析。结果急性加重组患者咽部草绿色链球菌(33.3%)、干燥奈瑟菌(25.0%)比例及菌群多样性(4.713±0.786)显著低于缓解组和对照组(均P0.05),致病菌铜绿假单胞菌、金黄色葡萄球菌、肺炎链球菌等比例及菌群总密集度均显著高于缓解组和对照组(均P0.05)。急性加重组患者CD3~+细胞、CD4~+细胞及CD4~+/CD8~+水平均显著低于缓解组和对照组(均P0.05)。Spearman相关性分析显示,COPD急性加重期患CD3~+细胞、CD4~+细胞及CD4~+/CD8~+水平与菌群总密集度均呈负相关,与菌群多样性均呈正相关(均P0.05)。结论 COPD急性加重期患者存在明显咽部菌群失衡,可引起机体免疫状态的紊乱。