Temporal and spatial fluctuations of heavy metals in Opa Reservoir,Ile-Ife,Nigeria

The Opa Reservoir, established for water supply to the Obafemi Awolowo University community, over the years has received direct linkage to township drains as a result of the widening and dredging of its river channels. The current study aimed at documenting monthly heavy metal loads at its riverine, transition and lacustrine zones in 2012–2013. Most of the heavy metals, analysed using an atomic absorption spectrophotometer, occurred within wide ranges, with coefficients of variation ranging from 60% to 300%, although the differences in heavy metal loads between the different zones were statistically insignificant at both the surface and bottom levels. The overall order of dominance of the metals was Ni > Cu > Fe > Zn > Cd = Cr > Pb, with nickel concentration being very high throughout. Heavy metal total mean concentration was higher during the rainy season (1.889 mg l?1) than the dry season (1.503 mg l?1) irrespective of sampling sites, having highly significant seasonal differences (p < 0.001) in Ni, Cd, Fe and Cu concentrations. The mean concentrations of Zn (0.074 mg l?1), Fe (0.176 mg l?1), Cu (0.507 mg l?1) and Pb (0.004 mg l?1) were within the WHO acceptable limit. However, the recorded levels of toxic elements Cd (0.031 mg l?1) and Ni (0.905 mg l?1) pose potential health risk to water consumers.     

Trophic ecology and persistence of invasive silver carp Hypophthalmichthys molitrix in an oligotrophic South African impoundment

The alien invasive silver carp Hypophthalmichthys molitrix established a self-sustaining feral population in an oligotrophic impoundment, Flag Boshielo Dam, in South Africa. The ability of this population to persist in a dam with low algal biomass (median annual suspended chlorophyll a = 0.08 µg l^?1), and limited access to rivers considered large enough for successful spawning, has implications for their invasive potential in other systems. Stomach content and stable isotope analysis were used to assess the trophic ecology of H. molitrix, which was then compared with indigenous Mozambique tilapia Oreochromis mossambicus, on a seasonal basis during 2011. Hypophthalmichthys molitrix are generalist filter feeders, with a diet consisting primarily of sediment, vegetative detritus, dinoflagellates and diatoms. The dominance of sediments in their stomachs suggests occasional benthic scavenging. However, H. molitrix occupied a higher trophic level (TL = 2.8) than expected, suggesting that this population subsidised their diet with an unidentified dietary constituent, characterised by enriched nitrogen values. Although the stomach contents indicated dietary overlap between H. molitrix and O. mossambicus, stable isotopes revealed fine-scale resource partitioning, despite both species occupying the same trophic level. Nonetheless, the persistence of this feral H. molitrix population in an oligotrophic impoundment highlights their phenotypic plasticity.     

基于红外相机技术分析鼬獾的活动节律

鼬獾(Melogale moschata)是食肉目鼬科鼬獾属动物,在我国分布广泛、种群数量丰富,但有关鼬獾的生态研究报导比较少.为掌握鼬獾的活动节律及其影响因素,2017年2月至2019年2月,利用红外相机技术对江西省桃红岭梅花鹿国家级自然保护区、九岭山国家级自然保护区和齐云山国家级自然保护区的鼬獾进行了监测,每个保护...     

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.     

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.     

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.     

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.     

Michael-type addition reactions for the in situ formation of poly(vinyl alcohol)-based hydrogels

Michael-type addition reactions offer the possibility to obtain in situ formation of polymeric hydrogels in the absence of a radical mechanism for the networking process. We explored such a synthetic route for obtaining a poly(vinyl alcohol) (PVA)-based hydrogel as a potential biomaterial for applications in vitro-retinal replacement surgery. The presence of radicals in the reaction medium can represent a risk for in situ surgical treatment. To circumvent this problem we have applied nucleophilic addition to ad hoc modified PVA macromers. The gel formation has been studied with respect to the timing required in this surgery and in terms of the structural characteristics of the obtained network.     

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。