Genomic, morphological and physiological data support fast ecotypic differentiation and incipient speciation in an alpine diving beetle.

An intricate interplay between evolutionary and demographic processes has frequently resulted in complex patterns of genetic and phenotypic diversity in alpine lineages, posing serious challenges to species delimitation and biodiversity conservation planning. Here we integrate genomic data, geometric morphometric analyses and thermal tolerance experiments to explore the role of Pleistocene climatic changes and adaptation to alpine environments on patterns of genomic and phenotypic variation in diving beetles from the taxonomically complex Agabus bipustulatus species group. Genetic structure and phylogenomic analyses revealed the presence of three geographically cohesive lineages, two representing trans-Palearctic and Iberian populations of the elevation-generalist A. bipustulatus and another corresponding to the strictly-alpine A. nevadensis, a narrow-range endemic taxon from the Sierra Nevada mountain range in southeastern Iberia. The best-supported model of lineage divergence, along with the existence of pervasive genetic introgression and admixture in secondary contact zones, is consistent with a scenario of population isolation and connectivity linked to Quaternary climatic oscillations. Our results suggest that A. nevadensis is an alpine ecotype of A. bipustulatus, whose genotypic, morphological and physiological differentiation likely resulted from an interplay between population isolation and local altitudinal adaptation. Remarkably, within the Iberian Peninsula, such ecotypic differentiation is unique to Sierra Nevada populations and has not been replicated in other alpine populations of A. bipustulatus. Collectively, our study supports fast ecotypic differentiation and incipient speciation processes within the study complex and points to Pleistocene glaciations and local adaptation along elevational gradients as key drivers of biodiversity generation in alpine environments.

Evolution of cold tolerance and thermal plasticity in life history, behaviour and physiology during a poleward range expansion.

Many species that are moving polewards encounter novel thermal regimes to which they have to adapt. Therefore, rapid evolution of thermal tolerance and of thermal plasticity in fitness-related traits in edge populations can be crucial for the success and speed of range expansions. We tested for adaptation in cold tolerance and in life history, behavioural and physiological traits and their thermal plasticity during a poleward range expansion. We reconstructed the thermal performance curves of life history (survival, growth and development rates), behaviour (food intake) and cold tolerance (chill coma recovery time) in the aquatic larval stage of the damselfly Ischnura elegans that is currently showing a poleward range expansion in northern Europe. We studied larvae from three edge and three core populations using a common-garden experiment. Consistent with the colder annual temperatures, larvae at the expansion front evolved an improved cold tolerance. The edge populations showed no overall (across temperatures) evolution of a faster life history that would improve their range-shifting ability. Moreover, consistent with damselfly edge populations from colder latitudes, edge populations evolved at the highest rearing temperature (28°C) a faster development rate, likely to better exploit the rare periods with higher temperatures. This was associated with a higher food intake and a lower metabolic rate. In conclusion, our results suggest that the edge populations rapidly evolved adaptive changes in trait means and thermal plasticity to the novel thermal conditions at the edge front. Our results highlight the importance of considering besides trait plasticity and the evolution of trait means, also the evolution of trait plasticity to improve forecasts of responses to climate change.

Durante su expansión hacia los polos, las especies encuentran nuevos regímenes de temperatura a los que tienen que adaptarse. Por esto, una rápida evolución de la tolerancia térmica y de la plasticidad térmica de rasgos fisiológicos clave en las poblaciones del borde del área de distribución es crucial para el éxito y la velocidad de las expansiones de rango. En este estudio testamos la adaptación de la tolerancia la frío y la plasticidad térmica de rasgos de historia de vida, comportamiento y fisiológicos durante una expansión de rango hacia el norte. Reconstruimos las curvas de rendimiento térmico de rasgos de historia de vida (supervivencia, tasa de crecimiento y tasa de desarrollo) y comportamiento (ingestión de alimento), así como la tolerancia al frío (tiempo de recuperación del coma por frío) en la larva acuática de la especie de caballito del diablo Ischnura elegans, especie que muestra un rango de expansión actual en el norte de Europa. Estudiamos larvas de tres poblaciones de la región de expansión norte y tres poblaciones de la región central usando experimentos en laboratorio. En concordancia con las temperaturas más bajas, las larvas del área de expansión mostraron mayor tolerancia al frío. Sin embargo, estas larvas no mostraron en general (a lo largo de las temperaturas estudiadas) evolución hacia una historia de vida más rápida, que aumentaría su habilidad para expandirse. Además, en consistencia con la menor temperatura de la región de expansión, las larvas presentaron mayor tasa de desarrollo a la temperatura experimental más alta (28°C), probablemente para explotar mejor los infrecuentes períodos con altas temperaturas en dicha región. Esto estuvo asociado con una mayor ingestión de alimento y una menor tasa metabólica. En conclusión, nuestros resultados sugieren que los valores medios y la plasticidad de los rasgos estudiados de las poblaciones del frente de expansión evolucionaron rápidamente para adaptarse a las nuevas condiciones térmicas en dicha región. Asimismo, nuestros resultados destacan la importancia de considerar, además de la media y plasticidad de los rasgos, la evolución de esta plasticidad, con el fin de mejorar las predicciones de las respuestas de las especies al cambio climático.

Setting individualized positive end-expiratory pressure level with a positive end-expiratory pressure decrement trial after a recruitment maneuver improves oxygenation and lung mechanics during one-lung ventilation.

BACKGROUND: We investigated whether individualized positive end-expiratory pressure (PEEP) improves oxygenation, ventilation, and lung mechanics during one-lung ventilation compared with standardized PEEP. METHODS: Thirty patients undergoing thoracic surgery were randomly allocated to the study or control group. Both groups received an alveolar recruitment maneuver at the beginning and end of one-lung ventilation. After the alveolar recruitment maneuver, the control group had their lungs ventilated with a 5 cm·H2O PEEP, while the study group had their lungs ventilated with an individualized PEEP level determined by a PEEP decrement trial. Arterial blood samples, lung mechanics, and volumetric capnography were recorded at multiple timepoints throughout the procedure. RESULTS: The individualized PEEP values in study group were higher than the standardized PEEP values (10 ± 2 vs 5 cm·H2O; P < 0.001). In both groups, arterial oxygenation decreased when bilateral-lung ventilation was switched to one-lung ventilation and increased after the alveolar recruitment maneuver. During one-lung ventilation, oxygenation was maintained in the study group but decreased in the control group. After one-lung ventilation, arterial oxygenation was significantly higher in the study group (306 vs 231 mm·Hg, P = 0.007). Static compliance decreased in both groups when bilateral-lung ventilation was switched to one-lung ventilation. Static compliance increased significantly only in the study group (P < 0.001) after the alveolar recruitment maneuver and optimal PEEP adjustment. The alveolar recruitment maneuver did not decrease cardiac index in any patient. CONCLUSIONS: During one-lung ventilation, the improvements in oxygenation and lung mechanics after an alveolar recruitment maneuver were better preserved by ventilation by using individualized PEEP with a PEEP decrement trial than with a standardized 5 cm·H2O of PEEP.

Virological and immunological features of active cytomegalovirus infection in nonimmunosuppressed patients in a surgical and trauma intensive care unit.

Cytomegalovirus (CMV) reactivation occurs frequently in critically ill patients. The natural course of CMV infection and the interaction between CMV and the adaptive immune system in this setting remain poorly defined. Fifty-three CMV-seropositive patients in a surgical and trauma intensive care unit were included in this study. The CMV DNA load in tracheal aspirates (TA) and plasma (PL) was monitored by qPCR. CMV-specific T-cell immunity was assessed by intracellular cytokine staining. Plasma TNF-alpha levels were determined by ELISA. CMV reactivation occurred in 39.7% of patients (23% had CMV DNA detected only in TA). The analysis of TA allowed an earlier diagnosis in 28% of patients. Clearance of CMV DNAemia preceded that of CMV DNA in TA in some episodes. Peak CMV DNA levels were significantly higher in TA than in PL (P = 0.02). CMV reactivation developed in the presence of CMV-specific T cells. Termination of CMV reactivation was associated with an expansion of functional CMV-specific T cells. Plasma levels of TNF-alpha did not allow for the prediction of the occurrence of CMV reactivation. CMV-specific T-cell immunity is preserved in most critically ill patients experiencing CMV reactivation. Analysis of respiratory specimens is imperative for an optimal monitoring of CMV reactivation in this setting.

Thermal evolution of life history and heat tolerance during range expansions toward warmer and cooler regions.

Species' range edges are expanding to both warmer and cooler regions. Yet, no studies directly compared the changes in range-limiting traits within the same species during both types of range expansions. To increase our mechanistic understanding of range expansions, it is crucial to disentangle the contributions of plastic and genetic changes in these traits. The aim of this study was to test for plastic and evolutionary changes in heat tolerance, life history, and behavior, and compare these during range expansions toward warmer and cooler regions. Using laboratory experiments we reconstructed the thermal performance curves (TPCurves) of larval life history (survival, growth, and development rates) and larval heat tolerance (CTmax) across two recent range expansions from the core populations in southern France toward a warmer (southeastern Spain) and a cooler (northwestern Spain) region in Europe by the damselfly Ischnura elegans. First-generation larvae from field-collected mothers were reared across a range of temperatures (16°-28°C) in incubators. The range expansion to the warmer region was associated with the evolution of a greater ability to cope with high temperatures (increased mean and thermal plasticity of CTmax), faster development, and, in part, a faster growth, indicating a higher time constraints caused by a shorter time frame available for larval development associated with a transition to a greater voltinism. Our results thereby support the emerging pattern that plasticity in heat tolerance alone is inadequate to adapt to new thermal regimes. The range expansion to the cooler region was associated with faster growth indicating countergradient variation without a change in CTmax. The evolution of a faster growth rate during both range expansions could be explained by a greater digestive efficiency rather than an increased food intake. Our results highlight that range expansions to warmer and cooler regions can result in similar evolutionary changes in the TPCurves for life history, and no opposite changes in heat tolerance.

Validated HPLC-UV detection method for the simultaneous determination of ceftolozane and tazobactam in human plasma.

AIM: A simple, rapid, economical and sensitive HPLC-UV method was developed for the simultaneous quantification of ceftolozane and tazobactam in plasma samples. METHODOLOGY: After deproteinization followed by a liquid-liquid back-extraction, the compounds were separated on a C18 column (150 mm × 4.6 mm, 5 µm) with UV-visible detection at 220 nm. The mobile phase consisted of acetonitrile and potassium dihydrogenphosphate buffer at pH 3.0 (8:92, v/v), delivered isocratically at a flow rate of 1.0 ml/min and at a column oven temperature of 30°C. Cefepime was used as an internal standard. RESULTS: Linearity was achieved in the concentration range of 0.50-100.00 µg/ml for ceftolozane and 0.25-50.00 µg/ml for tazobactam. The intra- and interday precision showed good reproducibility with coefficients of variation of less than 9.26% for ceftolozane and 9.62% for tazobactam. CONCLUSION: The sample preparation procedure avoids expensive or time-consuming steps used by other previously published methods. The methodology was validated according to standard guidelines and was used for quantification of ceftolozane and tazobactam in plasma samples from critically ill patients.

Effects of salinity changes on aquatic organisms in a multiple stressor context.

Under global change, the ion concentration of aquatic ecosystems is changing worldwide. Many freshwater ecosystems are being salinized by anthropogenic salt inputs, whereas many naturally saline ones are being diluted by agricultural drainages. This occurs concomitantly with changes in other stressors, which can result in additive, antagonistic or synergistic effects on organisms. We reviewed experimental studies that manipulated salinity and other abiotic stressors, on inland and transitional aquatic habitats, to (i) synthesize their main effects on organisms' performance, (ii) quantify the frequency of joint effect types across studies and (iii) determine the overall individual and joint effects and their variation among salinity-stressor pairs and organism groups using meta-analyses. Additive effects were slightly more frequent (54%) than non-additive ones (46%) across all the studies (n = 105 responses). However, antagonistic effects were dominant for the stressor pair salinity and toxicants (44%, n = 43), transitional habitats (48%, n = 31) and vertebrates (71%, n = 21). Meta-analyses showed detrimental additive joint effects of salinity and other stressors on organism performance and a greater individual impact of salinity than the other stressors. These results were consistent across stressor pairs and organism types. These findings suggest that strategies to mitigate multiple stressor impacts on aquatic ecosystems should prioritize restoring natural salinity concentrations.This article is part of the theme issue 'Salt in freshwaters: causes, ecological consequences and future prospects'.

How far could the alien boatman Trichocorixa verticalis verticalis spread? Worldwide estimation of its current and future potential distribution.

Invasions of alien species are considered among the least reversible human impacts, with diversified effects on aquatic ecosystems. Since prevention is the most cost-effective way to avoid biodiversity loss and ecosystem problems, one challenge in ecological research is to understand the limits of the fundamental niche of the species in order to estimate how far invasive species could spread. Trichocorixa verticalis verticalis (Tvv) is a corixid (Hemiptera) originally distributed in North America, but cited as an alien species in three continents. Its impact on native communities is under study, but it is already the dominant species in several saline wetlands and represents a rare example of an aquatic alien insect. This study aims: i) to estimate areas with suitable environmental conditions for Tvv at a global scale, thus identifying potential new zones of invasion; and ii) to test possible changes in this global potential distribution under a climate change scenario. Potential distributions were estimated by applying a multidimensional envelope procedure based on both climatic data, obtained from observed occurrences, and thermal physiological data. Our results suggest Tvv may expand well beyond its current range and find inhabitable conditions in temperate areas along a wide range of latitudes, with an emphasis on coastal areas of Europe, Northern Africa, Argentina, Uruguay, Australia, New Zealand, Myanmar, India, the western boundary between USA and Canada, and areas of the Arabian Peninsula. When considering a future climatic scenario, the suitability area of Tvv showed only limited changes compared with the current potential distribution. These results allow detection of potential contact zones among currently colonized areas and potential areas of invasion. We also identified zones with a high level of suitability that overlap with areas recognized as global hotspots of biodiversity. Finally, we present hypotheses about possible means of spread, focusing on different geographical scales.

[Echinocandins in a critically ill patient during continuous venovenous renal replacement]. / Tratamiento con equinocandinas en un paciente crítico sometido a técnica continua de reemplazo renal.

BACKGROUND: Critically ill patients with invasive candidiasis (IC) often suffer renal failure, which sometimes requires continuous renal replacement techniques (CRRT). Echinocandins are the first line treatment for IC in critically ill patients with mild or severe illness. Their elimination during CRRT should be negligible due to their pharmacokinetic and pharmacodynamic (PK/PD) profile, and dose adjustment are not needed, as suggested by the few reported clinical studies. CLINICAL CASE: This is the case of a 66 year old male who underwent surgery due to peritonitis secondary to intestinal suture dehiscence. The patient was admitted to ICU with septic shock symptoms and multiple organ dysfunction syndrome (MODS), and CRRT was started. Anidulafungin was prescribed at the usual dosage due to the IC risk factors present, and the observation of yeasts in the peritoneal fluid. Anidulafungin was selected due to the hepatic failure suffered by the patient. An isolate of Candida albicans susceptible to fluconazole was cultured from peritoneal fluid and rectal exudates. However, anidulafungin was maintained due to the MODS and observing the clearance of fluconazole during CRRT. The patient's condition improved favourably, being moved to the surgical ward 20 days after the surgery. CONCLUSIONS: Echinocandins, due to their PK/PD profile, could be safely given at usual doses to critically ill patients undergoing CRRT. However, new studies are required to strengthen this recommendation. Its extrahepatic metabolism makes anidulafungin a more attractive option among echinocandins and other antifungals when used in patients with different degrees of hepatic failure.

Cryopreserved and frozen hyaline cartilage imaged by environmental scanning electron microscope. An experimental and prospective study.

OBJECTIVE: To obtain images of the articular surface of osteochondral grafts (fresh, frozen, and cryopreserved in RPMI) using an environmental scanning electron microscope (ESEM). To evaluate and compare the main morphological aspects of the chondral surface of the fresh, frozen, and cryopreserved grafts as visualized via ESEM. METHODS: The study was based on osteochondral fragments from the internal condyle of the knee joint of New Zealand rabbits, corresponding to the chondral surface from fresh, frozen, and cryopreserved samples. One hundred ESEM images were obtained from each group and then classified according to a validated system. The kappa index and the corresponding concordance index were calculated, and the groups were compared by Pearson's chi-squared test (p < 0.05). RESULTS: The articular surface of cryopreserved osteochondral grafts had fewer even surfaces and filled lacunae and a higher number of empty lacunae as compared to fresh samples; these differences correspond to images of cell membrane lesions that lead to destruction of the chondrocyte. Frozen grafts showed more hillocky and knobby surfaces than did fresh grafts; they also had a greater number of empty chondrocyte lacunae. CONCLUSION: ESEM is useful for obtaining images of the surface of osteochondral grafts. When compared to fresh samples, cryopreservation in RPMI medium produces changes in the surface of hyaline cartilage, but to a lesser extent than those produced by freezing.

Tratamiento con equinocandinas en un paciente crítico sometido a técnica continua de reemplazo renal / Echinocandins in a critically ill patient during continuous venovenous renal replacement

Los pacientes críticos con candidiasis invasiva (CI) suelen presentar con frecuencia insuficiencia renal, por lo que en ocasiones requieren técnicas continuas de reemplazo renal (TCRR). Las equinocandinas son la primera opción en el tratamiento de la CI en el paciente crítico con enfermedad moderada o grave. Debido a su perfil farmacocinético y farmacodinámico (FC/FD), su eliminación durante las TCRR debe ser despreciable, sin que sea necesario ajustar sus dosis, como así lo indican los escasos estudios clínicos que hay al respecto. Caso clínico. Varón de 66 años intervenido por peritonitis secundaria a dehiscencia de sutura intestinal, que ingresa en la unidad de cuidados intensivos con cuadro clínico compatible con shock séptico y síndrome de disfunción multiorgánica (SDMO), por lo que se inicia TCRR. Al presentar factores de riesgo de CI, y al haberse observado levaduras en el líquido peritoneal, se pauta anidulafungina a dosis habituales. Se opta por anidulafungina debido a la insuficiencia hepática del paciente. En los cultivos del líquido peritoneal y exudado anal, se aísla Candida albicans sensible a fluconazol. No obstante, se decide mantener la anidulafungina debido al SDMO y al aclaramiento que presenta el fluconazol durante las TCRR. La evolución del paciente es favorable, y es trasladado a sala de hospitalización a los 20 días de la cirugía. Conclusiones. Dado su perfil FC/FD, las equinocandinas podrían administrarse con seguridad a dosis habituales en el paciente crítico con CI sometido a TCRR. No obstante, se requieren nuevos estudios que aporten más información para reforzar esta recomendación. El metabolismo extrahepático de la anidulafungina la hace especialmente interesante frente al resto de equinocandinas y otros antifúngicos en pacientes con diferentes grados de insuficiencia hepática(AU)

Background. Critically ill patients with invasive candidiasis (IC) often suffer renal failure, which sometimes requires continuous renal replacement techniques (CRRT). Echinocandins are the first line treatment for IC in critically ill patients with mild or severe illness. Their elimination during CRRT should be negligible due to their pharmacokinetic and pharmacodynamic (PK/PD) profile, and dose adjustment are not needed, as suggested by the few reported clinical studies. Clinical case. This is the case of a 66 year old male who underwent surgery due to peritonitis secondary to intestinal suture dehiscence. The patient was admitted to ICU with septic shock symptoms and multiple organ dysfunction syndrome (MODS), and CRRT was started. Anidulafungin was prescribed at the usual dosage due to the IC risk factors present, and the observation of yeasts in the peritoneal fluid. Anidulafungin was selected due to the hepatic failure suffered by the patient. An isolate of Candida albicans susceptible to fluconazole was cultured from peritoneal fluid and rectal exudates. However, anidulafungin was maintained due to the MODS and observing the clearance of fluconazole during CRRT. The patient's condition improved favourably, being moved to the surgical ward 20 days after the surgery. Conclusions. Echinocandins, due to their PK/PD profile, could be safely given at usual doses to critically ill patients undergoing CRRT. However, new studies are required to strengthen this recommendation. Its extrahepatic metabolism makes anidulafungin a more attractive option among echinocandins and other antifungals when used in patients with different degrees of hepatic failure(AU)