拉沙病毒分子流行病学特征和跨境传播风险

拉沙热主要流行于西非,经鼠传播,人群普遍易感,病死率高,暴发疫情频发,跨境传播时有发生。拉沙病毒易于传播,病毒分离、培养需在生物安全四级实验室(BSL-4)。2018年,世界卫生组织将其列为年度重点关注传染病,需加快研制防治关键技术手段。随着中非关系的日益紧密,贸易往来频繁,中国面临拉沙热的威胁显著增加。本文检索20世纪50年代首例拉沙热病例报道以来公开发表的主要文献,归纳拉沙热临床表现、病原学特征、流行病学特征、实验室检测以及跨境传播风险等,并对GenBank发布的全部287条拉沙病毒S基因编码区全长序列进行复核分析,以加强人们对拉沙热的了解,提高防控意识。     

湘西自治州不同产地火棘果实的营养成分

测定了产于湖南省湘西州吉首市、永顺县和凤凰县3个居群火棘果实的部分营养成分含量。结果表明,可溶性糖含量和蛋白质含量以吉首产火棘最高,分别为5.47%和7.13%,粗纤维含量以凤凰产火棘最高,为5.86%,维生素C含量以永顺县产火棘最高,为43.49 mg/100g。在吉首产同一居群火棘果实的不同采收期,可溶性糖和蛋白质含量随采摘期的延长而上升,粗纤维含量则下降。     

New insights into adaptation and population structure of cork oak using genotyping by sequencing

Species respond to global climatic changes in a local context. Understanding this process, including its speed and intensity, is paramount due to the pace at which such changes are currently occurring. Tree species are particularly interesting to study in this regard due to their long generation times, sedentarism, and ecological and economic importance. Quercus suber L. is an evergreen forest tree species of the Fagaceae family with an essentially Western Mediterranean distribution. Despite frequent assessments of the species’ evolutionary history, large‐scale genetic studies have mostly relied on plastidial markers, whereas nuclear markers have been used on studies with locally focused sampling strategies. In this work, “Genotyping by sequencing” is used to derive 1,996 single nucleotide polymorphism markers to assess the species’ evolutionary history from a nuclear DNA perspective, gain insights into how local adaptation is shaping the species’ genetic background, and to forecast how Q. suber may respond to global climatic changes from a genetic perspective. Results reveal (a) an essentially unstructured species, where (b) a balance between gene flow and local adaptation keeps the species’ gene pool somewhat homogeneous across its distribution, but still allowing (c) variation clines for the individuals to cope with local conditions. “Risk of Non‐Adaptedness” (RONA) analyses suggest that for the considered variables and most sampled locations, (d) the cork oak should not require large shifts in allele frequencies to survive the predicted climatic changes. Future directions include integrating these results with ecological niche modeling perspectives, improving the RONA methodology, and expanding its use to other species. With the implementation presented in this work, the RONA can now also be easily assessed for other organisms.     

First records of sea snakes (Elapidae: Hydrophiinae) diving to the mesopelagic zone (>200 m)

Viviparous sea snakes (Elapidae: Hydrophiinae) are fully marine reptiles distributed in the tropical and subtropical waters of the Indian and Pacific Oceans. Their known maximum diving depth ranges between 50 and 100 m and this is thought to limit their ecological ranges to shallow habitats. We report two observations, from industry‐owned remotely operated vehicles, of hydrophiine sea snakes swimming and foraging at depths of approximately 250 m in the Browse Basin on Australia's North West Shelf, in 2014 and 2017. These observations show that sea snakes are capable of diving to the dim‐lit, cold‐water mesopelagic zone, also known as the ‘twilight’ zone. These record‐setting dives raise new questions about the thermal tolerances, diving behaviour and ecological requirements of sea snakes. In addition to significantly extending previous diving records for sea snakes, these observations highlight the importance of university‐industry collaboration in surveying understudied deep‐sea habitats.     

Phosphonate inhibitors of West Nile virus NS2B/NS3 protease

West Nile virus (WNV) is a member of the flavivirus genus belonging to the Flaviviridae family. The viral serine protease NS2B/NS3 has been considered an attractive target for the development of anti-WNV agents. Although several NS2B/NS3 protease inhibitors have been described so far, most of them are reversible inhibitors. Herein, we present a series of α-aminoalkylphosphonate diphenyl esters and their peptidyl derivatives as potent inhibitors of the NS2B/NS3 protease. The most potent inhibitor identified was Cbz-Lys-Arg-(4-GuPhe)^P(OPh)₂ displaying K_i and k₂/K_i values of 0.4 µM and 28 265 M^?1s^?1, respectively, with no significant inhibition of trypsin, cathepsin G, and HAT protease.     

Flavivirus NS1 Triggers Tissue-Specific Vascular Endothelial Dysfunction Reflecting Disease Tropism

1. Download high-res image (205KB)
2. Download full-size image

     

Effects of aqueous smoke solutions and heat on seed germination of herbaceous species of the Sudanian savanna-woodland in Burkina Faso

Smoke generated by burning of plant materials has widely been recognized as a germination cue for some species from both fire prone and fire-free ecosystems. It is an important factor for the understanding of vegetation dynamics and could have potential use for ecological management and rehabilitation of disturbed areas. Individual species, however, seem to have a specific requirement for the type and dosage of smoke treatments. In the present study, six different concentrations of smoke solution were tested on 13 herbaceous species by soaking the seeds for 24 h. The germination of a forb species, Borreria scabra, was significantly stimulated (p<0.05) by the smoke treatment while that of the annual grass species, Euclasta condylotricha, was significantly inhibited (p<0.05) by 100% smoke solution treatment. Contrary to our expectation that another fire-related cue, heat shock, would break the physical dormancy of the species tested, it was not promotive. For non-dormant seeds of B. scabra and Borreria radiata, high temperatures were lethal while low temperature induced physiological dormancy that was overcome in the former species within 30 days of the germination trial. For some species, responses to smoke did not corroborate with the field-observed response to fire, making ecological interpretation challenging. For responsive species, the smoke treatment could be a simple approach for promoting their re-establishment in areas where it is needed. More investigations are needed to assess the spread of response to smoke.     

Phylogeography of the frog Leptodactylus validus (Amphibia: Anura): Patterns and timing of colonization events in the Lesser Antilles

The frog Leptodactylus validus occurs in northern South America, Trinidad and Tobago, and the southern Lesser Antilles (Grenada and St. Vincent). Mitochondrial DNA sequences were used to perform a nested clade phylogeographic analysis (NCPA), to date colonization events, and to analyze colonization patterns using on a relaxed molecular clock and coalescent simulations. L. validus originated on the mainland and first colonized Trinidad with subsequent independent colonizations of Tobago and the Lesser Antilles from Trinidad. The NCPA suggests a historical vicariant event between populations in Trinidad and Tobago from those in the Lesser Antilles. The colonization of Trinidad occurred 1 million years ago (mya) and the colonization of the Lesser Antillean islands occurred 0.4 mya. The coalescent approach supported the scenario where L. validus dispersed from Trinidad to St. Vincent and from there to Grenada, a dispersal event that could have been mediated by human introduction as recent as 1600 years ago.     

Bionomics of Anopheles spp. (Diptera: Culicidae) in a malaria endemic region of Sukabumi,West Java,Indonesia

A 15‐month bionomic study of Anopheles species was conducted in two ecologically distinct villages (coastal and upland) of Sukabumi District, West Java, Indonesia from June 2006 to September 2007. Mosquitoes were captured using human‐landing collections at both sites. During the study, a total of 17,100 Anopheles mosquitoes comprising 13 Anopheles species were caught: 9,151 at the coastal site and 7,949 at the upland site. Anopheles barbirostris, Anopheles maculatus, and Anopheles vagus were the predominant species caught at the coastal site, and Anopheles aconitus, Anopheles barbirostris, and An. maculatus predominated in the upland site. Overall, species were exophagic at both sites, but there was variation between species. Anopheles aconitus was endophagic at the coastal site, exophagic at the upland site, collected most often in April 2007 and had a peak landing time between 22:00 and 23:00. Anopheles sundaicus was only collected at the coastal site, exophagic, collected most often in October 2006, and had a peak landing time between 19:00 and 20:00. Potential malaria vector species such An. aconitus, An. maculatus, and An. sundaicus were present throughout the year. None of the 7,770 Anopheles tested using CSP‐ELISA were positive for malaria, although the risk for malaria outbreaks in Sukabumi district remains high.     

Vegetational and environmental history during the Holocene in the Esbjerg area, west Jutland, Denmark

A pollen diagram from a site in the Esbjerg area, western Denmark, is used for reconstruction of the Holocene vegetational and environmental history there. During the Atlantic there was a parallel development of the landscape to that of other areas in Jylland (Jutland). From the late Neolithic onwards the development took its own course related to the approaching North Sea, which periodically inundated parts of the Esbjerg area. The record reflects landscape development in a formerly marine valley where sediments seem to be missing from parts of the Bronze Age and the early Iron Age. Consequently the landscape development during these times is only reflected in glimpses in the vegetation record, which shows gradually more open woodland and increasing human impact. During the late part of the Iron Age, Viking period and Middle Ages, the woodland was diverse in taxa but became increasingly open, finally reaching a stage during which there may have been too little wood even for daily use. At the same time the use of the land intensified. During the Sub-Atlantic, the Esbjerg area offered good natural resources with extensive grazing areas in the marine marshes in addition to good possibilities for farming and use of the woodland on higher ground, but devastating floods occurred.