215 research outputs found

    Diversity in small mammals from eastern Lake Turkana, Kenya

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    Rodents and insectivores were surveyed, using live trapping, at seven sites on the eastern side of Lake Turkana, one of the remotest parts of Kenya, and at study areas of biological distinctiveness, such as Sibiloi National Park and the Mount Kulal Biosphere Reserve. A total of 191 individuals of 11 species were captured, but only two rodents (Acomys percivali Dollman 1911 and A. wilsoni Thomas 1982) were numerous at two sites. The presence of the lesser Egyptian gerbil Gerbillus gerbillus Olivier 1801 is a new record for Kenya. We were unable to arrive at a conclusive explanation of the differences in species richness and in habitat use that we recorded for the seven sites, because our samples were too limited. However, certain patterns suggest the influence of different factors, such as habitat diversity, ecological isolation (the forest of Mount Kulal), and geographic isolation (Central Island, in the lake). It is possible that the impact of livestock overgrazing is a major limiting factor for small mammal communities

    Challenges in the Diagnosis and Management of Bacterial Lung Infections in Solid Organ Recipients: A Narrative Review

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    Respiratory infections pose a significant threat to the success of solid organ transplantation, and the diagnosis and management of these infections are challenging. The current narrative review addressed some of these challenges, based on evidence from the literature published in the last 20 years. Specifically, we focused our attention on (i) the obstacles to an etiologic diagnosis of respiratory infections among solid organ transplant recipients, (ii) the management of bacterial respiratory infections in an era characterized by increased antimicrobial resistance, and (iii) the development of antimicrobial stewardship programs dedicated to solid organ transplant recipient

    Chromosomal mapping of ribosomal clusters and telomeric sequences (TTAGG)n in nine species of lobsters (Crustacea, Decapoda)

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    Lobsters are ubiquitous, economically important decapod crustaceans with apparently conflicting evolutionary relationships. Here, we describe the chromosomal location of the major (45S rDNA) and minor (5S rDNA) ribosomal gene families in four species of Astacidea and five of Achelata, using two-color FISH. The major ribosomal family is located in 4–16 sites per diploid chromosome set, with Nephrops norvegicus (Nephropidae) showing the highest number described so far in Decapoda. The 5S rDNA is located in two sites in eight species; only in the crayfish Procambarus clarkii the 5S FISH signals were detected in four sites together with additional weaker signals. Furthermore, in N. norvegicus the minor ribosomal genes are syntenic with one major ribosomal cluster. Moreover, we located by two-color FISH the pentanucleotide (TTAGG)n telomeric repeat in the Nephropidae studied, showing the occurrence of a colocalization with 45S ribosomal sequences in Homarus gammarus. The comparison of chromosomal locations of repetitive sequences in Mediterranean, Atlantic, and South African lobster species as well as in marine and freshwater ones provides information on chromosomal evolution and cytotaxonomy of Decapoda

    New insights on the systematics of echinoids belonging to the family Spatangidae Gray, 1825 using a combined approach based on morphology, morphometry, and genetics

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    Spatangoids are probably the least resolved group within echinoids, with known topological incongruencies between phylogenies derived from molecular (very scarce) and morphological data. The present work, based on the analysis of 270 specimens of Spatangidae (Echinoidea, Spatangoida) trawled in the Sardinian seas (Western Mediterranean), allowed us to verify the constancy of some characters that we consider to be diagnostic at the genus level —such as the path of the subanal fasciole and the relationship between labrum and adjacent ambulacral plates —and to distinguish two distinct forms within the studied material. Based on morphological characters, morphometrics, and molecular analyses (sequencing of two mitochondrial markers: cytochrome c oxidase subunit1 (COI) and 16S), most of the individuals were classified as morphotype A and attributed to the species Spatangus purpureus, the most common spatangoid in the Mediterranean Sea, while a few corresponded to a different morphotype (B), genetically close to the species Spatangus raschi. Preliminary morphological analyses seemed to indicate that morphotype B specimens from Sardinia are slightly different from S. raschi and from Spatangus subinermis individuals, the second species of the family known to occur in the Mediterranean Sea. On the basis of morpho-structural observations and molecular analyses, comparing Mediterranean living forms with species from other areas (Central Eastern Atlantic, North Sea and neighboring basins, South African Sea, Philippines and Indonesian Archipelago, New Zealand, and Hawaiian Islands), the clear distinction of S. purpureus from several other species classified as Spatangus was confirmed. Based on the morphological and genetic differences, we propose to maintain the genus Spatangus including in it only the type species S. purpureus among the living species and to establish the new genus Propespatagus nov. gen. to include several other species previously classified as Spatangus. The clear distinction among different genera was also detected in fossil forms of Spatangus, Propespatagus nov. gen., and Sardospatangus (†) from the European Oligo-Miocene sedimentary rocks of Germany; the Miocene of Ukraine, Italy, and North Africa; the Plio-Pleistocene of Italy; and the Mio-Pliocene of Florida (USA). The new data can help in addressing taxonomic ambiguities within echinoids, as well as in improving species identification, and hence biodiversity assessments in the Mediterranean region

    Organic enrichment can increase the impact of microplastics on meiofaunal assemblages in tropical beach systems

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    The cumulative impact of microplastic and organic enrichment is still largely unknown. Here, we investigated the microplastic contamination, the organic enrichment and their effects on meiofaunal distribution and diversity in two islands of the Maldivian archipelago: one more pristine, and another strongly anthropized. Field studies were coupled with manipulative experiments in which microplastic polymers were added to sediments from the non-anthropized island (i.e., without organic enrichment) to assess the relative effect of microplastic pollution on meiofauna assemblages. Our results reveal that the impact of microplastic contamination on meiofaunal abundance and taxa richness was more significant in the anthropized island, which was also characterized by a significant organic enrichment. Meiofauna exposed experimentally to microplastic contamination showed: i) the increased abundance of opportunistic nematodes and copepods and ii) a shift in the trophic structure, increasing relevance in epistrate-feeder nematodes. Based on all these results, we argue that the coexistence of chronic organic enrichment and microplastics can significantly increase the ecological impacts on meiofaunal assemblages. Since microplastic pollution in the oceans is predicted to increase in the next decades, its negative effects on benthic biodiversity and functioning of tropical ecosystems are expected to worsen especially when coupled with human-induced eutrophication. Urgent actions and management plans are needed to avoid the cumulative impact of microplastic and organic enrichment

    Incidence of human brucellosis in the Kilimanjaro Region of Tanzania in the periods 2007-2008 and 2012-2014

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    Background: Brucellosis causes substantial morbidity among humans and their livestock. There are few robust estimates of the incidence of brucellosis in sub-Saharan Africa. Using cases identified through sentinel hospital surveillance and health care utilization data, we estimated the incidence of brucellosis in Moshi Urban and Moshi Rural Districts, Kilimanjaro Region, Tanzania, for the periods 2007–2008 and 2012–2014. Methods: Cases were identified among febrile patients at two sentinel hospitals and were defined as having either a 4-fold increase in Brucella microscopic agglutination test titres between acute and convalescent serum or a blood culture positive for Brucella spp. Findings from a health care utilization survey were used to estimate multipliers to account for cases not seen at sentinel hospitals. Results: Of 585 patients enrolled in the period 2007–2008, 13 (2.2%) had brucellosis. Among 1095 patients enrolled in the period 2012–2014, 32 (2.9%) had brucellosis. We estimated an incidence (range based on sensitivity analysis) of brucellosis of 35 (range 32–93) cases per 100 000 persons annually in the period 2007–2008 and 33 (range 30–89) cases per 100 000 persons annually in the period 2012–2014. Conclusions: We found a moderate incidence of brucellosis in northern Tanzania, suggesting that the disease is endemic and an important human health problem in this area

    Mycobacterial Interspersed Repetitive-Unit–Variable-Number Tandem-Repeat Analysis and Beijing/W Family of Mycobacterium tuberculosis

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    Comment on: M. Hanekom, G.D. van der Spuy, N. C. Gey van Pittius, C. R. E. McEvoy, S. L. Ndabambi, T.C. Victor, E.G. Hoal, P.D. van Helden, R.M. Warren, Evidence that the spread of Mycobacterium tuberculosis strains with the Beijing genotype is human population dependent, J Clin Microbiol. 2007 Jul;45(7):2263-6

    Primate rhythmic categories analyzed on an individual basis

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    Rhythm is a fundamental feature characterizing communicative displays, and recent studies showed that primate songs encompass categorical rhythms falling on small integer ratios observed in humans. We individually assessed the presence and sexual dimorphism of rhythmic categories, analyzing songs emitted by 39 wild indris. Considering the intervals between the units given during each song, we extracted 13556 interval ratios and found three peaks (at around 0.33, 0.47, and 0.70). Two peaks indicated rhythmic categories corresponding to small integer ratios (1:1, 2:1). All individuals showed a peak at 0.70, and most showed those at 0.47 and 0.33. In addition, we found sex differences in the peak at 0.47 only, with males showing lower values than females. This work investigates the presence of individual rhythmic categories in a non-human species; further research may highlight the significance of rhythmicity and untie selective pressures that guided its evolution across species, including humans

    Combined COI barcode-based methods to avoid mislabelling of threatened species of deep-sea skates

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    Skates are characterised by conservative body morphology which hampers identification and leads to frequent taxonomic confusion and market mislabelling. Accurate specimen classification is crucial for reliable stock assessments and effective conservation plans, otherwise the risk of extinction could be unnoticed. The misclassification issue is evident for the genus Dipturus, distributed worldwide, from the continental shelf and slope to the deep sea. In this study, barcode cytochrome oxidase I gene (COI) sequences were used along with species delimitation and specimen assignment methods to improve taxonomy and zoogeography of species of conservation interest inhabiting the Atlantic Ocean and Mediterranean Sea. In this study, we provided new evidence of the occurence of D. nidarosiensis in the Central-Western Mediterranean Sea and the lack of Atlantic-Mediterranean genetic divergence. The Atlantic endangered species D. laevis and D. batis clustered together under the same molecular operational taxonomic unit (MOTU) with any delimitation methods used, while the assignment approach correctly discriminated specimens into the two species. These results provided evidence that the presence of the barcode gap is not an essential predictor of identification success, but the use of different approaches is crucially needed for specimen classification, especially when threshold- or tree-based methods result less powerful. The analyses also showed how different putative, vulnerable, species dwelling across South-Western Atlantic and South-Eastern Pacific are frequently misidentified in public sequence repositories. Our study emphasised the limits associated to public databases, highlighting the urgency to verify and implement the information deposited therein in order to guarantee accurate species identification and thus effective conservation measures for deep-sea skates
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