Ghrelin在小鼠体内早期胚胎发育中的表达

为了探讨Ghrelin是否在昆明系小白鼠(Mus musculus)体内早期胚胎发育中发挥作用。运用激素超排卵技术及动物解剖学方法获取小鼠体内不同发育阶段的早期胚胎,应用实时定量PCR技术检测了Ghrelin mRNA的相对表达量。结果表明,Ghrelin mRNA在小鼠各期胚胎中均有表达;同时,GhrelinmRNA的表达量呈现一定规律性变化,2-细胞期表达量最低,8-细胞期表达量达到最高值,总体趋势是先降低后升高之后又降低。研究结果揭示,Ghrelin可能在小鼠早期胚胎发育中发挥一定的作用。     

Use of vector control to protect people from sleeping sickness in the focus of Bonon (Côte d’Ivoire)

BackgroundGambian human African trypanosomiasis (gHAT) is a neglected tropical disease caused by Trypanosoma brucei gambiense transmitted by tsetse flies (Glossina). In Côte d’Ivoire, Bonon is the most important focus of gHAT, with 325 cases diagnosed from 2000 to 2015 and efforts against gHAT have relied largely on mass screening and treatment of human cases. We assessed whether the addition of tsetse control by deploying Tiny Targets offers benefit to sole reliance on the screen-and-treat strategy.Methodology and principal findingsIn 2015, we performed a census of the human population of the Bonon focus, followed by an exhaustive entomological survey at 278 sites. After a public sensitization campaign, ~2000 Tiny Targets were deployed across an area of 130 km² in February of 2016, deployment was repeated annually in the same month of 2017 and 2018. The intervention’s impact on tsetse was evaluated using a network of 30 traps which were operated for 48 hours at three-month intervals from March 2016 to December 2018. A second comprehensive entomological survey was performed in December 2018 with traps deployed at 274 of the sites used in 2015. Sub-samples of tsetse were dissected and examined microscopically for presence of trypanosomes. The census recorded 26,697 inhabitants residing in 331 settlements. Prior to the deployment of targets, the mean catch of tsetse from the 30 monitoring traps was 12.75 tsetse/trap (5.047–32.203, 95%CI), i.e. 6.4 tsetse/trap/day. Following the deployment of Tiny Targets, mean catches ranged between 0.06 (0.016–0.260, 95%CI) and 0.55 (0.166–1.794, 95%CI) tsetse/trap, i.e. 0.03–0.28 tsetse/trap/day. During the final extensive survey performed in December 2018, 52 tsetse were caught compared to 1,909 in 2015, with 11.6% (5/43) and 23.1% (101/437) infected with Trypanosoma respectively.ConclusionsThe annual deployment of Tiny Targets in the gHAT focus of Bonon reduced the density of Glossina palpalis palpalis by >95%. Tiny Targets offer a powerful addition to current strategies towards eliminating gHAT from Côte d’Ivoire.     

不同退化红砂荒漠草地的水分分配格局

研究了内蒙古阿拉善盟不同过牧退化红砂草地的土壤 植物 大气系统的水分分配格局、不同退化草地和主要植物种的水分利用效率 .2 0 0 1年降雨量 12 4 .3mm ,其中试验期 119.4mm .1m深土壤水分结果表明 ,10～ 4 0cm土层受蒸散影响最大 ;由于主要共存种红砂和无芒隐子草根系分布和蒸腾强度不同等 ,含水量在 10～ 2 0cm土层以中度退化区显著低于其它样区 (P <0 .0 5 ) ,而 2 0～ 4 0cm土层以轻度退化区较低 .样地年均蒸发量为 30 .6mm ,红砂种群的年均蒸腾量为 11.9mm .随着草地退化加剧 ,裸地的蒸发量和退化指示种匍根骆驼蓬种群的蒸腾量增加 ,而红砂种群的蒸腾量降低 .与较轻度退化区比 ,中度和重度退化区的水分利用率分别下降了 14 .6 %和 4 6 .1% ,红砂水分利用率分别下降了 37.8%和 73.8% .     

Topology independent protein structural alignment

Background  

Identifying structurally similar proteins with different chain topologies can aid studies in homology modeling, protein folding, protein design, and protein evolution. These include circular permuted protein structures, and the more general cases of non-cyclic permutations between similar structures, which are related by non-topological rearrangement beyond circular permutation. We present a method based on an approximation algorithm that finds sequence-order independent structural alignments that are close to optimal. We formulate the structural alignment problem as a special case of the maximum-weight independent set problem, and solve this computationally intensive problem approximately by iteratively solving relaxations of a corresponding integer programming problem. The resulting structural alignment is sequence order independent. Our method is also insensitive to insertions, deletions, and gaps.     

Feather ornaments are dynamic traits in the Great Tit Parus major

In behavioural studies it has been common to quantify plumage colours or ornaments over a range of dates and link them to fitness characteristics without accounting for seasonal changes in these traits. Such changes are likely to be widespread among birds, yet we lack assessments of this variability within individuals. We studied both within‐ and between‐individual temporal changes in Great Tit Parus major ornaments, specifically the melanin‐based black breast stripe and the pigment‐free white cheek patch. During the non‐breeding season both ornaments varied. In juveniles and adult females, the area of the breast stripe first rose and then, from near the end of December, decreased. In adult males there was a linear decrease. In the cheek patch, the irregularity of the cheek borders showed either a linear (adults) or a non‐linear (juveniles) increase as the season progressed. In individuals repeatedly sampled during the same winter, the decrease in the size of the breast stripe was larger for males than females and there was an overall decrease in the regularity of the cheek borders. There was no relationship between the size of the breast stripe and the white cheek patch irregularities or the cheek patch area. These results imply that more attention should be paid to quantification, within individuals, of the components of expression of phenotypic traits. In addition, we suggest that further research should focus on explaining the causes and functions of ornament change.     

Dysregulated cellular redox status during hyperammonemia causes mitochondrial dysfunction and senescence by inhibiting sirtuin-mediated deacetylation

Perturbed metabolism of ammonia, an endogenous cytotoxin, causes mitochondrial dysfunction, reduced NAD⁺/NADH (redox) ratio, and postmitotic senescence. Sirtuins are NAD⁺-dependent deacetylases that delay senescence. In multiomics analyses, NAD metabolism and sirtuin pathways are enriched during hyperammonemia. Consistently, NAD⁺-dependent Sirtuin3 (Sirt3) expression and deacetylase activity were decreased, and protein acetylation was increased in human and murine skeletal muscle/myotubes. Global acetylomics and subcellular fractions from myotubes showed hyperammonemia-induced hyperacetylation of cellular signaling and mitochondrial proteins. We dissected the mechanisms and consequences of hyperammonemia-induced NAD metabolism by complementary genetic and chemical approaches. Hyperammonemia inhibited electron transport chain components, specifically complex I that oxidizes NADH to NAD⁺, that resulted in lower redox ratio. Ammonia also caused mitochondrial oxidative dysfunction, lower mitochondrial NAD⁺-sensor Sirt3, protein hyperacetylation, and postmitotic senescence. Mitochondrial-targeted Lactobacillus brevis NADH oxidase (MitoLbNOX), but not NAD+ precursor nicotinamide riboside, reversed ammonia-induced oxidative dysfunction, electron transport chain supercomplex disassembly, lower ATP and NAD⁺ content, protein hyperacetylation, Sirt3 dysfunction and postmitotic senescence in myotubes. Even though Sirt3 overexpression reversed ammonia-induced hyperacetylation, lower redox status or mitochondrial oxidative dysfunction were not reversed. These data show that acetylation is a consequence of, but is not the mechanism of, lower redox status or oxidative dysfunction during hyperammonemia. Targeting NADH oxidation is a potential approach to reverse and potentially prevent ammonia-induced postmitotic senescence in skeletal muscle. Since dysregulated ammonia metabolism occurs with aging, and NAD⁺ biosynthesis is reduced in sarcopenia, our studies provide a biochemical basis for cellular senescence and have relevance in multiple tissues.     

The synthesis of short- and medium-chain-length poly(hydroxyalkanoate) mixtures from glucose- or alkanoic acid-grown <Emphasis Type="Italic">Pseudomonas oleovorans</Emphasis>

Pseudomonas oleovorans NRRL B-778 accumulated mixtures of poly-3-hydroxybutyrate (PHB) and medium-chain-length poly(hydroxyalkanoates) (mcl-PHAs) when grown on glucose, octanoic acid or oleic acid, whereas growth on nonanoic acid or undecanoic acid resulted in copolymers of poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHB-co-HV). Acetone fractionation verified the presence of PHB/mcl-PHA mixtures. The acetone-insoluble (AIS) fractions of the polymers derived from glucose (PHA-glucose), octanoic acid (PHA-octanoic) and oleic acid (PHA-oleic) were exclusively PHB while the acetone-soluble (AS) fractions contained mcl-PHA composed of differing ratios of 3-hydroxy-acid monomer units, which ranged in chain length from 6 to 14 carbon atoms. In contrast, both the AIS and AS fractions from the polymers derived from nonanoic acid (PHA-nonanoic) and undecanoic acid (PHA-undecanoic) were composed of comparable ratios of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV). The unfractionated PHA-glucose, PHA-octanoic and PHA-oleic polymers had melting temperatures (T _m) between 177 and 179°C, enthalpies of fusion (ΔH _f) of 20 cal/g and glass transition temperatures (T _g) of 3–4°C. This was due to the large PHB content in the polymer mixtures. On the other hand, the PHA-nonanoic and PHA-undecanoic polymers had thermal properties that supported their copolymer nature. In both cases, the T _m values were 161°C, ΔH _f values were 7cal/g and T _g values were −3°C. Journal of Industrial Microbiology & Biotechnology (2002) 28, 147–153 DOI: 10.1038/sj/jim/7000231 Received 30 July 2001/ Accepted in revised form 04 November 2001     

Analysis of Amblyomma sculptum haplotypes in an area endemic for Brazilian spotted fever

Amblyomma sculptum (Ixodida: Ixodidae) Berlese, 1888, a member of the Amblyomma cajennense complex, is the major vector of Brazilian spotted fever (BSF) in southeastern Brazil. In this study, the genetic diversity of A. sculptum populations in the state of Rio de Janeiro (RJ), Brazil, was investigated because genetic variability in tick populations may be related to vector competence. Samples of A. sculptum from 19 municipalities in 7 regions of RJ were subjected to DNA extraction, amplification and sequencing of D‐loop, cytochrome oxidase II and 12S rDNA mitochondrial genes. These sequences were used to map the genetic diversity of this tick. Amblyomma sculptum populations are genetically diverse in RJ, especially in the South Centre and Highland regions. Few unique haplotypes were observed in all populations, and the majority of genetic variation found was among ticks within each population. Phylogenetic reconstruction reinforced the assumption that all the haplotypes identified in RJ belong to A. sculptum. However, some RJ haplotypes are closer to A. sculptum from Argentina than to A. sculptum from elsewhere in Brazil. In RJ, A. sculptum has high genetic diversity, although little genetic differentiation. Observations also indicated a high level of gene flow among the studied populations and no evidence of population structure according to region in RJ.     

我国巴拉巴按蚊形态描述

白踝按蚊种团是由很多形态近似的蚊种组成,其中巴拉巴按蚊和白踝按蚊均为东南亚一带的重要传疟媒介。我国过去资料均记载为白踝按蚊,但未从形态上详细鉴定。为了确定该种的分类地位,1963年作者等在海南岛万宁县兴隆附近山林区采集“白踝按蚊”全套标本10批共150多套,1971年后从云南省采集少数标本进行形态鉴定,发现其与Colless(1956,1957)所描述的白踝按蚊Anopheles leucosphyrus leucosphyrus Donitz(1901)有很明显的差别,而与巴拉巴按蚊A.balabacensis balabacensis Balsas(1936)除某些特征略有差异外,余均完全一致。按Colless的分类法,过去我国记载的“白踝按蚊”,应鉴定为巴拉巴按蚊A.balabacensis balabacensis Baisas。     

Evolutionary origins of Brassicaceae specific genes in Arabidopsis thaliana

Background  

All sequenced genomes contain a proportion of lineage-specific genes, which exhibit no sequence similarity to any genes outside the lineage. Despite their prevalence, the origins and functions of most lineage-specific genes remain largely unknown. As more genomes are sequenced opportunities for understanding evolutionary origins and functions of lineage-specific genes are increasing.