Extinction debt and functional traits mediate community saturation over large spatiotemporal scales.

Determining if ecological communities are saturated (have a limit to the number of species they can support) has important implications for understanding community assembly, species invasions, and climate change. However, previous studies have generally been limited to short time frames that overlook extinction debt and have not explicitly considered how functional trait diversity may mediate patterns of community saturation. Here, we combine data from biodiversity surveys with functional and phylogenetic data to explore if the colonisation events after the Great American Biotic Interchange (closure of the Panamanian Isthmus) resulted in increases in species richness of communities of the snake family Dipsadidae. We determined the number and the direction of dispersal events between Central and South America by estimating ancestral areas based on a Bayesian time-calibrated phylogenetic analysis. We then evaluated whether variation in community saturation was mediated by the functional similarity of six traits for the resident and colonizing snakes and/or local environmental conditions. We found that colonised communities did not support more species than those that were not colonised. Moreover, we did not find an association between the functional diversity across sites and whether they were colonised by members from the lineages dispersing across the Isthmus or not. Instead, variation in species richness was predicted best by covariates such as time since colonisation and local environment. Taken together, our results suggest that snake communities of the Dipsadidae across the neotropics are saturated. Moreover, our research highlights two important factors to consider in studies of community saturation: extinction debt and the functional differences and similarities in species' ecological roles.

Determinar si las comunidades ecológicas están saturadas (si tienen un límite en el número de especies que pueden albergar) tiene importantes implicaciones para entender el ensamblaje de comunidades, las invasiones de especies y el cambio climático. Sin embargo, los estudios previos en esta área se han limitado generalmente a marcos temporales cortos, ignorando el concepto de deuda de extinción y no considerando explícitamente cómo la diversidad de rasgos funcionales puede mediar en los patrones de saturación de las comunidades. En este trabajo combinamos datos publicados de muestreos de campo con datos funcionales y filogenéticos para explorar si los eventos de colonización después del Gran Intercambio Biótico Americano (ocurrido con el cierre del istmo de Panamá) resultaron en aumentos en la riqueza de especies de las comunidades de la familia de serpientes Dipsadidae. Determinamos el número y la dirección de los eventos de dispersión entre América Central y América del Sur mediante la estimación de áreas ancestrales basada en un análisis filogenético Bayesiano calibrado en el tiempo. Luego evaluamos si la variación en la saturación de las comunidades estaba mediada por la similitud funcional de seis rasgos para las serpientes residentes y colonizadoras y/o por las condiciones ambientales locales. Encontramos que las comunidades colonizadas no contienen más especies que aquellas que no fueron colonizadas. Además, no encontramos ninguna relación entre la diversidad funcional de los sitios considerados y el hecho de que estuvieran colonizados o no por miembros de los linajes que se dispersaron a través del Istmo. En cambio, la variación en la riqueza de especies se predijo mejor por covariantes como el tiempo transcurrido desde la colonización y el clima local. En conjunto, nuestros resultados sugieren que las comunidades de Dipsadidae a lo largo del neotrópico están saturadas. Además, nuestra investigación destaca dos factores importantes a considerar en los estudios de saturación de comunidades: la existencia de una deuda de extinción y las diferencias y similitudes funcionales en los papeles ecológicos de las especies.

A new species of the genus Gonatodes (Squamata: Sauria: Sphaerodactylidae) from the western flank of the Cordillera Oriental in Colombia, with description of its hemipenial morphology.

We describe a new sphaerodactylid lizard of the genus Gonatodes from the western flank of the Cordillera Oriental, Santander Department, Colombia based on morphological and molecular data. The new species is distinguished from all congeners by having a medium body size, by the absence of both a supraciliary spine and of clusters of distinctly enlarged conical scales on the sides and by having a subcaudal scale pattern (1'1") and a cryptic dorsal color pattern in both sexes. Additionally, we describe for the first time the hemipenial morphology for a species of the genus. The new species increases the number of Gonatodes known from Colombia to eight and is the only known species of the country, as well as the second known mainland species of the genus not exhibiting sexual dichromatism.

Carriers of cystic fibrosis among sperm donors: complete CFTR gene analysis versus CFTR genotyping.

OBJECTIVE: To determine the frequency of cystic fibrosis (CF) carriers among sperm donors in Spain studied through a complete analysis of the CFTR gene and to compare the results with those that would have been obtained by the 4 genotyping panels of the CFTR gene most commonly used as a carrier test in the context of assisted reproduction in our country. DESIGN: Descriptive observational study. SETTING: Private center. PATIENTS: Nine hundred thirty-five sperm donors, from January 2014 to June 2019. INTERVENTION: None. MAIN OUTCOME MEASURE: Presence of pathogenic variants in the CFTR gene. RESULTS: 17% of the donors were carriers of at least 1 pathogenic variant in CFTR, with 39 different pathogenic variants detected. Only 4 of these 39 variants (10.27%) would have been detected by the 4 genotyping tests considered, and 22 variants (56.41%) would not have been detected by any of the genotyping tests. The pathogenic variants of the CFTR gene included in the different genotyping tests analyzed vary widely, and <50% are common to all of them. CONCLUSIONS: Although the was not based in the general population, these results show that the use of genotyping tests is associated with a high reproductive risk, because the rate of detection of CF carriers was lower when these panels were applied, in comparison with the complete study of the CFTR gene. We recommend that complete sequencing of the CFTR gene by next-generation sequencing be performed as a screening method for CF in sperm donors.

A snapshot of antimicrobial resistance in Mexico. Results from 47 centers from 20 states during a six-month period.

AIM: We aimed to assess the resistance rates of antimicrobial-resistant, in bacterial pathogens of epidemiological importance in 47 Mexican centers. MATERIAL AND METHODS: In this retrospective study, we included a stratified sample of 47 centers, covering 20 Mexican states. Selected isolates considered as potential causatives of disease collected over a 6-month period were included. Laboratories employed their usual methods to perform microbiological studies. The results were deposited into a database and analyzed with the WHONET 5.6 software. RESULTS: In this 6-month study, a total of 22,943 strains were included. Regarding Gram-negatives, carbapenem resistance was detected in ≤ 3% in Escherichia coli, 12.5% in Klebsiella sp. and Enterobacter sp., and up to 40% in Pseudomonas aeruginosa; in the latter, the resistance rate for piperacillin-tazobactam (TZP) was as high as 19.1%. In Acinetobacter sp., resistance rates for cefepime, ciprofloxacin, meropenem, and TZP were higher than 50%. Regarding Gram-positives, methicillin resistance in Staphylococcus aureus (MRSA) was as high as 21.4%, and vancomycin (VAN) resistance reached up to 21% in Enterococcus faecium. Acinetobacter sp. presented the highest multidrug resistance (53%) followed by Klebsiella sp. (22.6%) and E. coli (19.4%). CONCLUSION: The multidrug resistance of Acinetobacter sp., Klebsiella sp. and E. coli and the carbapenem resistance in specific groups of enterobacteria deserve special attention in Mexico. Vancomycin-resistant enterococci (VRE) and MRSA are common in our hospitals. Our results present valuable information for the implementation of measures to control drug resistance.

The Decline in HIV-1 Drug Resistance in Heavily Antiretroviral-Experienced Patients Is Associated with Optimized Prescriptions in a Treatment Roll-Out Program in Mexico.

A decrease in the rate of acquired antiretroviral (ARV) drug resistance (ADR) over time has been documented in high-income settings, but data on the determinants of this phenomenon are lacking. We tested the hypothesis that in heavily ARV-experienced patients in the Mexican ARV therapy (ART) roll-out program, the drop in ADR would be associated with changes in ARV drug usage. Genotypic resistance tests obtained from 974 HIV-infected patients with virological failure and at least 2 previously failed ARV regimens from throughout the country were analyzed for the presence of nucleos(t)ide reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, and protease inhibitor (PI) resistance-associated mutations (RAMs). Patients were divided into two groups according to their first ART start date: 488 patients initiated ART before mid-2003 (group 1) and 486 after mid-2003 (group 2). The rate of RAMs, median resistance score of several sentinel ARVs, and composition of ART drugs in patient's entire treatment history were compared between both groups. Patients in group 2 were less likely to have >3 thymidine analogue-associated mutations (TAMs) and >3 PI-mRAMs [adjusted odds ratio (aOR) = 0.37; 95% confidence interval (95% CI) = 0.25-0.54; p < .001 and aOR = 0.53; 95% CI = 0.36-0.77; p = .001, respectively] and had a significantly lower resistance score for zidovudine, tenofovir, ritonavir-boosted (r)-lopinavir, r-atazanavir, and r-darunavir than group 1 patients. A significantly lower proportion of patients in group 2 used monotherapy, bitherapy, thymidine analogue-containing regimens, nonboosted PI-containing regimens, and low resistance barrier PI-containing regimens. In Mexican ARV-experienced patients, the occurrence of TAM and PI-mRAM has significantly declined over time. This can be explained by treatment optimization in the national ART roll-out program in recent years.

Procedure control and acceptance sampling plans for donor sperm banks: a theoretical study.

The publication of European Directive 2004/23/EC in the European Parliament and in the European Council on 31 March 2004 concerning the setting of standards of quality and safety for the donation, procurement, testing, processing, preservation, storage and distribution of human cells and tissues made it obligatory for sperm banks to set up quality control systems to ensure, among other goals, the satisfactory control of all procedures carried out. The objective of the present study is to set out guidelines that will make it possible to ensure the quality of the donors and frozen specimens accepted and the homogeneity of the samples supplied by a sperm bank. For this purpose, we shall describe clear-cut criteria for the acceptance of donors and frozen sperm, taking into account both analytic variability and the biological variations to be expected in semen parameters. Furthermore, we shall show how the evaluation of the results of a frozen semen specimen, on the basis of analysing a single straw after such freezing, does not guarantee the homogeneity of all the straws. Therefore, we must design a sampling plan to take into consideration all the straws obtained from a donor. This kind of plan will depend on different parameters, such as acceptable levels of quality and the tolerable rate of straws with defective semen, and will involve certain risks, both for the sperm bank and for the client. The establishment of these acceptance control criteria for frozen specimens and for donors could be of practical use for the control of the procedures applied in the operation of a sperm bank.