57 research outputs found

    Development of a 16S Reference Library for eDNA Metabarcoding the Freshwater Fishes of Western Ecuador.

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    This project examines the use of the 16S locus to amplify neotropical freshwater fishes native to Western Ecuador in a newly created 16S reference library for DNA barcoding and eDNA metabarcoding applications. Among the orders Characiformes, Siluriformes, Cichliformes, Gobiiformes, Cryprinodontiformes, Gymnotiformes, and Perciformes, a compendium of 105 specimens were sequenced, with 43 representing new 16S sequences previously unavailable on Genbank

    First record of Iotabrycon praecox Roberts 1973 (Characidae: Stevardiinae) in the Santa Rosa drainage, southwestern Ecuador

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    Iotabrycon praecox (Characidae: Stevardiinae) has been reported as endemic to the Guayas River drainage in Western Ecuador since its description in 1973. We collected one specimen of I. praecox in the Santa Rosa River, Santa Rosa drainage, El Oro Province, approximately 144 km south of the Guayas drainage, significantly expanding the known geographic distribution of the species. Given the severe anthropomorphic pressures impacting fishes in Southwestern Ecuador, there is an urgent need to evaluate the present status of I. praecox in the region

    Frequency of Ectodysplasin alleles and limited introgression between sympatric threespine stickleback populations. Environ

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    Abstract The threespine stickleback (Gasterosteus aculeatus) is primitively an anadromous or resident marine species but has repeatedly colonized fresh water, where predictable phenotypic divergence usually occurs rapidly. A conspicuous element of this divergence is change of the number and position of lateral armor plates from about 33 that cover the entire flank (complete) to <10 anterior plates (low). This difference is caused primarily by variation at the Ectodysplasin (Eda) locus. The low Eda allele appears to be rarer in two geographically adjacent anadromous populations from Cook Inlet, Alaska than in most marine or anadromous populations reported from elsewhere, and there is no evidence of elevated gene flow for Eda between anadromous and resident lake threespine stickleback populations that breed in sympatry. However, the two anadromous populations are divergent for the frequencies of two complete Eda alleles. It is not clear how monomorphic low-plated freshwater populations in Cook Inlet have almost invariably acquired ancestral low Eda alleles from anadromous ancestors in which this allele appears to be extremely rare

    Evolutionary diversification of body form and the axial skeleton in the Gasterosteoidei: the sticklebacks and their closest relatives

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    ABSTRACT Background: Many fishes have evolved long bodies. Decades of research have uncovered substantial variability in body form within the threespine stickleback (Gasterosteus aculeatus) and among its relatives in the Gasterosteoidei, including the evolution of extremely long bodies. Elongation is likely to be associated with the evolution of the axial skeleton but we need studies linking variation in length and the axial skeleton. Objectives: Examine the relationship between body form and vertebral variation in the Gasterosteoidei (the sticklebacks and their closest relatives). Methods: We examined samples of all genera of the Gasterosteidae, Aulorhynchidae, and Hypoptychidae, collected throughout their ranges. We examined body form variation using geometric morphometric methods and the fineness ratio. We obtained total vertebral number and the proportion of precaudal to caudal vertebrae from X-rays of the same specimens. Results: Mean total vertebral number varied from 26.8 in Gasterosteus wheatlandi to 54.5 in Hypoptychus dybowskii. Body shape was significantly related to total vertebral number across taxa, with longer bodied species having more vertebrae. Hypoptychus dybowskii, which has more vertebrae than predicted from its relative body length, is an outlier. The number of precaudal and caudal vertebrae covary linearly across taxa. Again, Hypoptychus dybowskii was an exception, having an excess of precaudal vertebrae for the number of caudal vertebrae that it possesses. Apeltes quadracus was a second exception, having an excess of caudal vertebrae for the number of precaudal vertebrae that it possesses. In summary, changes in the relative proportions of the body are typically accompanied by corresponding changes in vertebral number. Differences in the number of caudal vertebrae appear to be particularly important among some of the morphologically more similar genera like Gasterosteus, Culaea, and Pungitius. Consistent with the hypothesis of pleomerism, vertebral number was also associated with body size, such that larger species have more vertebrae

    Range expansion of the genus Sicydium (Teleostei: Gobiidae) to coastal mountain streams of southwestern Ecuador and possibly northwestern Peru

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    We report collections of several specimens of Sicydium in 2013 and 2014 from the Jubones and Santa Rosa Rivers in southwestern Ecuador. These collections substantially expand the known range of the genus southward. The specimens are tentatively identified as Sicydium cf. rosenbergii based on their morphology. Small differences in morphology among specimens from the two rivers are noted, as are discrepancies with the type description. A museum database search uncovered two additional records of the genus south of their previously recognized range including one record from northwestern Peru

    Persistent Organic Pollutants and Mercury in Genetically Identified Inner Estuary Bottlenose Dolphin (Tursiops truncatus) Residents of the Guayaquil Gulf, Ecuador: Ecotoxicological Science in Support of Pollutant Management and Cetacean Conservation

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    The bottlenose dolphin is one of the most common cetaceans found in the coastal waters, estuaries, and mangroves of Ecuador. However, its population size is gradually declining in the Gulf of Guayaquil, and anthropogenic factors including habitat degradation, uncontrolled dolphin watching, dredging activities, increasing maritime traffic, underwater noise, bycatch, and marine pollution have been implicated in their decline. Very little is known about contamination by persistent organic pollutants (POPs) and mercury in bottlenose dolphins from the Pacific coast of South America. To address this research gap, the first assessment of total mercury (THg) and POPs, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs), in free-ranging bottlenose dolphins in mangroves (El Morro Mangrove Wildlife Refuge) of the Gulf of Guayaquil, was conducted in Ecuador in 2018. Dolphin samples (i.e., skin and blubber; n = 9), were obtained using dart biopsy field methods for contaminant analysis. POP concentrations ranged from 0.56 to 13.0 mg/kg in lipid weight, while THg ranged from 1.92 to 3.63 mg/kg in dry weight. The predominant POPs were OCPs (50% of ÎŁPOP), followed by PCBs (46%) and PBDEs (6.0%); particularly, p,pâ€Č-DDE, the main DDT metabolite and a potent anti-androgenic, accounting for 42% of ÎŁPOP, ranging from 0.12 to ∌7.0 mg/kg lw, followed by PCB 153 (8.0%) and PCB 180 (5.0%). PBDE 47 accounted for 2.0% of ÎŁPOP. While the POP concentrations are lower than those found in dolphins from many other regions of the world, some of the THg concentrations are within the concentration range found in dolphins from the southeastern coast of the United States. The ecotoxicological risk assessment showed that some of the sampled dolphins are exposed to immunotoxic and endocrine disruption effects by POPs and mercury. The low genetic diversity of this distinctive dolphin population, likely exhibiting genetic isolation and a unique evolutionary heritage, could be lost if the population continues to decline in the face of anthropogenic threats, including chemical pollution. Our finding shows that bottlenose dolphins in coastal Ecuador are exposed to environmental contaminants and can be used as sentinel species for ecosystem health to monitor pollution in the region and to support ecotoxicological risk assessment and regional pollutant management

    Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

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    Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

    Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

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    Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

    Global urban environmental change drives adaptation in white clover

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    Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale
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