Mosquitoes of the Namibian Zambezi Region and their associated viruses

A large diversity of viruses is transmitted by hematophagous mosquitoes. Among them are several infectious agents of major concern for human health, like dengue virus, chikungunya virus, Zika virus, yellow fever virus, Japanese encephalitis virus, and West Nile virus. Apart from arboviruses that infect vertebrate hosts, mosquitoes also harbor a range of insect-specific viruses that can have an influence on the transmission of other mosquito viruses. In this work, a baseline study was conducted on the mosquitoes of the Namibian Zambezi Region and their accompanying viruses. Mosquito sampling was performed in National Parks and Conservancies across four different land-use types, including undisturbed habitats and areas used for agriculture or pasture. The mosquito community composition was investigated, and infection rates with arboviruses and insect-specific viruses were determined. Most sampling locations showed a high diversity of different mosquito species, which supported an equally high genetic diversity of RNA viruses from all the relevant families of mosquito viruses. Established arboviruses, like West Nile virus, were identified among the virus detections. Further, we could detect a high number of putatively novel viruses, most of which were mosquito-specific viruses from the viral families Flaviviridae and Phenuiviridae. No conclusive correlation could be derived between mosquito host biodiversity and RNA virus infection prevalence. Instead, mosquito community composition was found to have a significant impact on the infection prevalence of the viruses studied.Eine große Vielfalt von Viren wird durch hämatophage Stechmücken übertragen. Darunter finden sich mehrere Infektionserreger, die von großer Bedeutung für die menschliche Gesundheit sind, wie Dengue-Virus, Chikungunya-Virus, Zika-Virus, Gelbfieber-Virus, Japanisches-Enzephalitis-Virus und West-Nil-Virus. Neben Arboviren, die Wirbeltierwirte infizieren, beherbergen Stechmücken auch eine Reihe insektenspezifischer Viren, die einen Einfluss auf die Übertragung anderer Stechmückenviren haben können. In dieser Arbeit wurde eine Basisstudie zu den Stechmücken der namibischen Sambezi Region und ihren Viren durchgeführt. Hierzu wurden in Nationalparks und Naturschutzgebieten Stechmücken aus vier verschiedenen Landnutzungstypen gesammelt, darunter ungestörte Lebensräume und landwirtschaftlich oder als Weideland genutzte Gebiete. Die Zusammensetzung der Mückengemeinschaft wurde untersucht und die Infektionsraten mit Arboviren und insektenspezifischen Viren wurden bestimmt. Die meisten Probenahmestellen zeigten eine hohe Diversität verschiedener Stechmückenarten, die eine ebenso hohe genetische Diversität von RNA-Viren aus allen relevanten Familien von Stechmückenviren aufwiesen. Unter den Virenfunden wurden auch etablierte Arboviren wie das West-Nil-Virus identifiziert. Darüber hinaus konnten wir eine große Anzahl mutmaßlich neuartiger Viren nachweisen, von denen die meisten stechmückenspezifischen Viren aus den Virusfamilien Flaviviridae und Phenuiviridae sind. Es konnte keine abschließende Korrelation zwischen der Stechmückenbiodiversität und der Prävalenz von RNA-Virusinfektionen abgeleitet werden. Stattdessen wurde die Zusammensetzung der Stechmückengemeinschaft als wesentlicher Einfluss auf die Infektionsprävalenz der untersuchten Viren identifiziert

Ocean warming is the key filter for successful colonization of the migrant octocoral Melithaea erythraea (Ehrenberg, 1834) in the Eastern Mediterranean Sea

Climate, which sets broad limits for migrating species, is considered a key filter to species migration between contrasting marine environments. The Southeast Mediterranean Sea (SEMS) is one of the regions where ocean temperatures are rising the fastest under recent climate change. Also, it is the most vulnerable marine region to species introductions. Here, we explore the factors which enabled the colonization of the endemic Red Sea octocoral Melithaea erythraea (Ehrenberg, 1834) along the SEMS coast, using sclerite oxygen and carbon stable isotope composition (delta O-18(SC) and delta C-13(SC)), morphology, and crystallography. The unique conditions presented by the SEMS include a greater temperature range (similar to 15 degrees C) and ultra-oligotrophy, and these are reflected by the lower delta C-13(SC) values. This is indicative of a larger metabolic carbon intake during calcification, as well as an increase in crystal size, a decrease of octocoral wart density and thickness of the migrating octocoral sclerites compared to the Red Sea samples. This suggests increased stress conditions, affecting sclerite deposition of the SEMS migrating octocoral. The delta(OSC)-O-18 range of the migrating M. erythraea indicates a preference for warm water sclerite deposition, similar to the native depositional temperature range of 21-28 degrees C. These findings are associated with the observed increase of minimum temperatures in winter for this region, at a rate of 0.35 +/- 0.27 degrees C decade(-1) over the last 30 years, and thus the region is becoming more hospitable to the IndoPacific M. erythraea. This study shows a clear case study of "tropicalization" of the Mediterranean Sea due to recent warming

Spectral Diversity and Regulation of Coral Fluorescence in a Mesophotic Reef Habitat in the Red Sea

The phenomenon of coral fluorescence in mesophotic reefs, although well described for shallow waters, remains largely unstudied. We found that representatives of many scleractinian species are brightly fluorescent at depths of 50–60 m at the Interuniversity Institute for Marine Sciences (IUI) reef in Eilat, Israel. Some of these fluorescent species have distribution maxima at mesophotic depths (40–100 m). Several individuals from these depths displayed yellow or orange-red fluorescence, the latter being essentially absent in corals from the shallowest parts of this reef. We demonstrate experimentally that in some cases the production of fluorescent pigments is independent of the exposure to light; while in others, the fluorescence signature is altered or lost when the animals are kept in darkness. Furthermore, we show that green-to-red photoconversion of fluorescent pigments mediated by short-wavelength light can occur also at depths where ultraviolet wavelengths are absent from the underwater light field. Intraspecific colour polymorphisms regarding the colour of the tissue fluorescence, common among shallow water corals, were also observed for mesophotic species. Our results suggest that fluorescent pigments in mesophotic reefs fulfil a distinct biological function and offer promising application potential for coral-reef monitoring and biomedical imaging

Global biogeography of coral recruitment: tropical decline and subtropical increase

Despite widespread climate-driven reductions of coral cover on tropical reefs, little attention has been paid to the possibility that changes in the geographic distribution of coral recruitment could facilitate beneficial responses to the changing climate through latitudinal range shifts. To address this possibility, we compiled a global database of normalized densities of coral recruits on settlement tiles (corals m(-2)) deployed from 1974 to 2012, and used the data therein to test for latitudinal range shifts in the distribution of coral recruits. In total, 92 studies provided 1253 records of coral recruitment, with 77 % originating from settlement tiles immersed for 3-24 mo, herein defined as long-immersion tiles (LITs); the limited temporal and geographic coverage of data from short-immersion tiles (SITs; deployed for 20 degrees latitude). These trends indicate that a global decline in coral recruitment has occurred since 1974, and the persistent reduction in the densities of recruits in equatorial latitudes, coupled with increased densities in sub-tropical latitudes, suggests that coral recruitment may be shifting poleward

Focal Spot, Spring 2005

https://digitalcommons.wustl.edu/focal_spot_archives/1099/thumbnail.jp

Myostatin-2 gene structure and polymorphism of the promoter and first intron in the marine fish Sparus aurata: evidence for DNA duplications and/or translocations

<p>Abstract</p> <p>Background</p> <p>Myostatin (MSTN) is a member of the transforming growth factor-ß superfamily that functions as a negative regulator of skeletal muscle development and growth in mammals. Fish express at least two genes for <it>MSTN</it>: <it>MSTN-1 </it>and <it>MSTN-2</it>. To date, <it>MSTN-2 </it>promoters have been cloned only from salmonids and zebrafish.</p> <p>Results</p> <p>Here we described the cloning and sequence analysis of <it>MSTN-2 </it>gene and its 5' flanking region in the marine fish <it>Sparus aurata </it>(sa<it>MSTN-2</it>). We demonstrate the existence of three alleles of the promoter and three alleles of the first intron. Sequence comparison of the promoter region in the three alleles revealed that although the sequences of the first 1050 bp upstream of the translation start site are almost identical in the three alleles, a substantial sequence divergence is seen further upstream. Careful sequence analysis of the region upstream of the first 1050 bp in the three alleles identified several elements that appear to be repeated in some or all sequences, at different positions. This suggests that the promoter region of sa<it>MSTN-2 </it>has been subjected to various chromosomal rearrangements during the course of evolution, reflecting either insertion or deletion events. Screening of several genomic DNA collections indicated differences in allele frequency, with allele 'b' being the most abundant, followed by allele 'c', whereas allele 'a' is relatively rare. Sequence analysis of sa<it>MSTN-2 </it>gene also revealed polymorphism in the first intron, identifying three alleles. The length difference in alleles '1R' and '2R' of the first intron is due to the presence of one or two copies of a repeated block of approximately 150 bp, located at the 5' end of the first intron. The third allele, '4R', has an additional insertion of 323 bp located 116 bp upstream of the 3' end of the first intron. Analysis of several DNA collections showed that the '2R' allele is the most common, followed by the '4R' allele, whereas the '1R' allele is relatively rare. Progeny analysis of a full-sib family showed a Mendelian mode of inheritance of the two genetic loci. No clear association was found between the two genetic markers and growth rate.</p> <p>Conclusion</p> <p>These results show for the first time a substantial degree of polymorphism in both the promoter and first intron of <it>MSTN-2 </it>gene in a perciform fish species which points to chromosomal rearrangements that took place during evolution.</p