MICROBIAL ASSOCIATIONS WITH METCALF’S TRYONIA, TRYONIA METCALFI (GASTROPODA: COCHLIOPIDAE), AN IMPERILED CI´ENEGA ENDEMIC

The Chihuahuan Desert swamps are a hotspot for imperiled organisms including freshwater springsnails and bacteria. Many of these taxa are endemic to the desert and to the individual waterbodies where they occur. Efforts to conserve diversity in these threatened areas must account for the life history of the organisms, but also interactions between organisms including microbes. We documented the microbial assemblage associated with Tryonia metcalfi, a critically imperiled freshwater snail endemic to a ciénega system in western Texas. We identified 14 bacterial families in our snail samples and determined a core assemblage of 19 bacterial taxa (4 of which represented novel lineages) that are likely dependent on the snail. Future conservation efforts involving T. metcalfi and its environment should therefore consider the microbial diversity associated with both the snail and the ciénegas. - En las ciénegas del desierto de Chihuahua habitan muchos organismos en peligro, entre ellos caracoles de agua dulce y bacterias. Muchos de estos taxones son endémicos del desierto y de los específicos cuerpos de agua donde ocurren. Esfuerzos para conservar la diversidad en estas áreas amenazadas deben tomar en cuenta la historia de vida de los organismos junto con las interacciones entre ellos, incluyendo microbios. Documentamos el conjunto microbiano relacionado con Tryonia metcalfi, una especie de caracol de agua dulce en peligro de extinción, endémica a un sistema de ciénagas en el oeste de Texas. Identificamos 14 familias bacterianas en nuestras muestras de caracoles y determinamos un conjunto principal de 19 taxones bacterianos; cuatro representan nuevos linajes, que probablemente dependen del caracol. En el futuro, los esfuerzos para proteger a T. metcalfi y su ambiente en consecuencia deben considerarla diversidad microbiana asociada con esta especie de caracol y la ciénega

Two Complete Mitochondrial Genomes from \u3cem\u3ePraticolella mexicana\u3c/em\u3e Perez, 2011 (Polygyridae) and Gene Order Evolution in Helicoidea (Mollusca, Gastropoda)

Helicoidea is a diverse group of land snails with a global distribution. While much is known regarding the relationships of helicoid taxa, comparatively little is known about the evolution of the mitochondrial genome in the superfamily. We sequenced two complete mitochondrial genomes from Praticolella mexicana Perez, 2011 representing the first such data from the helicoid family Polygyridae, and used them in an evolutionary analysis of mitogenomic gene order. We found the mitochondrial genome of P. mexicana to be 14,008 bp in size, possessing the typical 37 metazoan genes. Multiple alternate stop codons are used, as are incomplete stop codons. Mitogenome size and nucleotide content is consistent with other helicoid species. Our analysis of gene order suggested that Helicoidea has undergone four mitochondrial rearrangements in the past. Two rearrangements were limited to tRNA genes only, and two involved protein coding genes

Two complete mitochondrial genomes from Praticolella mexicana Perez, 2011 (Polygyridae) and gene order evolution in Helicoidea (Mollusca, Gastropoda)

Helicoidea is a diverse group of land snails with a global distribution. While much is known regarding the relationships of helicoid taxa, comparatively little is known about the evolution of the mitochondrial genome in the superfamily. We sequenced two complete mitochondrial genomes from Praticolella mexicana Perez, 2011 representing the first such data from the helicoid family Polygyridae, and used them in an evolutionary analysis of mitogenomic gene order. We found the mitochondrial genome of P. mexicana to be 14,008 bp in size, possessing the typical 37 metazoan genes. Multiple alternate stop codons are used, as are incomplete stop codons. Mitogenome size and nucleotide content is consistent with other helicoid species. Our analysis of gene order suggested that Helicoidea has undergone four mitochondrial rearrangements in the past. Two rearrangements were limited to tRNA genes only, and two involved protein coding gene

Two complete mitochondrial genomes from Praticolella mexicana Perez, 2011 (Polygyridae) and gene order evolution in Helicoidea (Mollusca, Gastropoda)

Helicoidea is a diverse group of land snails with a global distribution. While much is known regarding the relationships of helicoid taxa, comparatively little is known about the evolution of the mitochondrial genome in the superfamily. We sequenced two complete mitochondrial genomes from Praticolella mexicana Perez, 2011 representing the first such data from the helicoid family Polygyridae, and used them in an evolutionary analysis of mitogenomic gene order. We found the mitochondrial genome of P. mexicana to be 14,008 bp in size, possessing the typical 37 metazoan genes. Multiple alternate stop codons are used, as are incomplete stop codons. Mitogenome size and nucleotide content is consistent with other helicoid species. Our analysis of gene order suggested that Helicoidea has undergone four mitochondrial rearrangements in the past. Two rearrangements were limited to tRNA genes only, and two involved protein coding gene

Relationship between stream velocity & depth and snail size distribution & density of the balcones elimia, elimia comalensis (pilsbry, 1890) (gastropoda: pleuroceridae) in comal springs, texas

Pleurocerid snails are important components of aquatic ecosystems and the majority of species are threatened or endangered. This study describes aspects of the life-history of Elimia comalensis, specifically population density in relationship to water velocity and depth, and seasonal change. Also examined are spatial segregation of different E. comalensis age groups and the relationship of snail size (proxy for age) to flow, depth, and seasonal change. The study was carried out in the lotic portion of spring run 3, Comal Springs, New Braunfels, Texas, by quadrat sampling at 10 m intervals from the spring head to Landa Lake in Fall, Winter, and Spring 2005-2006. The length of snails was strongly influenced by physical characteristics of the stream with stream depth, water velocity, and distance from the spring head accounting for -43% of the individual variability for shell length (

CHANGES IN SHELL MORPHOLOGY OF ELIMIA COMALENSIS (GASTROPODA: PLEUROCERIDAE) FROM THE EDWARDS PLATEAU, TEXAS

Species in the pleurocerid genus Elimia are important components of freshwater systems in the eastern United States, but little is known about their natural history. Using dual-simultaneous linear regression and principal components analyses, we show patterns of morphological change in two populations of E. comalensis from the Edwards Plateau, Texas. Both populations had similar rates of change for all shell measurements analyzed, and both showed similar decreases in growth as total length of shell increased. However, the size at which growth slowed was different between populations, and small shells tended to have a consistent shape, while larger shells were more variable. - Aunque las especies del ge´nero Elimia son componentes importantes de los sistemas de agua dulce del este de los Estados Unidos, se sabe poco de su historia natural. Usando dos ana´lisis, uno de regresio´n linear dual simulta´nea y otro de componentes principales, mostramos patrones de cambio morfolo´gico en dos poblaciones de E. comalensis del Edwards Plateau, Texas. Las dos tuvieron tazas de cambios similares para todas las medidas de conchas analizadas y las dos tuvieron disminuciones similares en el crecimiento mientras la longitud total de concha aumentaba. Sin embargo, el taman˜o al que el crecimiento disminuyo´ fue diferente entre las poblaciones y las conchas pequen˜as tendieron a tener una forma consistente y las conchas ma´s grandes fueron ma´s variables

A review of freshwater gastropod conservation: challenges and opportunities

North American freshwater gastropods remain an understudied, yet critically imperiled, fauna. As part of a larger discussion on freshwater mollusks in this special issue, we review 4 specific areas of concern regarding freshwater gastropods and discuss how best to address those concerns in the context of conservation. Areas of concern include freshwater gastropod conservation strategies, taxonomy and systematics, ecological research, and conservation challenges. We illustrate how each of these topics relates to conservation efforts and discuss opportunities to improve our baseline knowledge of freshwater gastropod taxonomy, ecology, and conservation. We emphasize throughout that effective conservation strategies require the participation of as many affected and interested groups, from local communities to governmental agencies, as possible for successful implementation and management. We offer suggestions for the direction of cooperative conservation with regard to freshwater gastropods. The freshwater gastropod fauna of the USA and Canada consists of 842 nominal taxa (NatureServe 2007). This fauna is increasingly imperiled by river regulation, habitat loss, poor water quality, reduced water quantity, and invasive species. Estimates suggest that .40% of freshwater snail species are negatively affected by anthropogenic factors (Neves et al. 1997), resulting in many extinctions in North America (Master et al. 2000). More than 60% of the total nominal freshwater snail fauna have global ranks of G1 (critically imperiled), G2 (imperiled), or GH–GX (presumed or possibly extinct; Fig. 1), and recent extinctions support these rankings (Sada and Vinyard 2002, Hershler et al. 2007). Less than ¼ of all North American taxa are thought to be secure (G5) or apparently secure (G4; NatureServe 2007). The US Fish and Wildlife Service lists 23 species of snails as endangered or threatened (Table 1). Our objectives are to summarize what is known about freshwater gastropod conservation needs in North America (Brown et al. 2008, Perez and Minton 2008), highlight critical knowledge gaps that negative-ly affect conservation efforts, and suggest a logical path for future work

Development and validation of the ISARIC 4C Deterioration model for adults hospitalised with COVID-19: a prospective cohort study.

BACKGROUND: Prognostic models to predict the risk of clinical deterioration in acute COVID-19 cases are urgently required to inform clinical management decisions. METHODS: We developed and validated a multivariable logistic regression model for in-hospital clinical deterioration (defined as any requirement of ventilatory support or critical care, or death) among consecutively hospitalised adults with highly suspected or confirmed COVID-19 who were prospectively recruited to the International Severe Acute Respiratory and Emerging Infections Consortium Coronavirus Clinical Characterisation Consortium (ISARIC4C) study across 260 hospitals in England, Scotland, and Wales. Candidate predictors that were specified a priori were considered for inclusion in the model on the basis of previous prognostic scores and emerging literature describing routinely measured biomarkers associated with COVID-19 prognosis. We used internal-external cross-validation to evaluate discrimination, calibration, and clinical utility across eight National Health Service (NHS) regions in the development cohort. We further validated the final model in held-out data from an additional NHS region (London). FINDINGS: 74 944 participants (recruited between Feb 6 and Aug 26, 2020) were included, of whom 31 924 (43·2%) of 73 948 with available outcomes met the composite clinical deterioration outcome. In internal-external cross-validation in the development cohort of 66 705 participants, the selected model (comprising 11 predictors routinely measured at the point of hospital admission) showed consistent discrimination, calibration, and clinical utility across all eight NHS regions. In held-out data from London (n=8239), the model showed a similarly consistent performance (C-statistic 0·77 [95% CI 0·76 to 0·78]; calibration-in-the-large 0·00 [-0·05 to 0·05]); calibration slope 0·96 [0·91 to 1·01]), and greater net benefit than any other reproducible prognostic model. INTERPRETATION: The 4C Deterioration model has strong potential for clinical utility and generalisability to predict clinical deterioration and inform decision making among adults hospitalised with COVID-19. FUNDING: National Institute for Health Research (NIHR), UK Medical Research Council, Wellcome Trust, Department for International Development, Bill & Melinda Gates Foundation, EU Platform for European Preparedness Against (Re-)emerging Epidemics, NIHR Health Protection Research Unit (HPRU) in Emerging and Zoonotic Infections at University of Liverpool, NIHR HPRU in Respiratory Infections at Imperial College London