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Amphibian populations in montane habitats are often subjected to high thermal variability, which may exacerbate anthropogenic impacts such as the introduction of exotic species. Here, we present data from two experiments exploring the joint effects of rising temperatures and the presence of waterborne cues from an exotic predatory fish on the short- and long-term antipredatory responses (i.e. activity and time to metamorphosis respectively) of Rana iberica and Salamandra salamandra larvae from two montane amphibian populations. We found some evidence of a cumulative effect of an increase in temperature and the presence of predators. Although predator recognition was not precluded at rising temperatures, we observed an increase in larval activity in warmer water, which might negatively affect survival by favoring prey detectability by predators. We also observed a strong quadratic effect of temperature and a joint effect of temperature and predators on larval development: at intermediate temperatures, larvae exposed to exotic trout cues had greatly accelerated metamorphosis. These results suggest that warmer conditions might be particularly harmful for larvae in montane wetlands enduring the presence of exotic predators. [ABSTRACT FROM AUTHOR]

The article presents an investigation conducted to determine chemical communication in competitive interactions among tropical stream detritivores. The study focuses on the four most common shredder species present thereat, namely: Anisocentropus kirramus Neboiss 1980 (Trichoptera Calamoceratidae); Lectrides varians Mosely 1953; Triplectides gonetalus Morse and Neboiss 1982 (Trichoptera Leptoceridae); and Atalophlebia sp. (Ephemeroptera Leptophlebiidae). Results of the investigation are presented, analyzed, explained and discussed.

Abstract The phylogenetic relationships among primitive anurans remain controversial, even when several morphological and molecular approaches have been used in an attempt to resolve them. Nevertheless, very little effort has been made to study these relationships with behavioural data. We studied the relation between some precopulatory behaviour characters (male call characteristics and call recognition by females) and the different proposed phylogenies among the anuran genera Alytes, Discoglossus and Bombina . Different acoustic variables were analysed from male calls of different species of these genera; Alytes cisternasii females were used in recognition tests with calls from those species. A phenetic tree generated from male call characteristics grouped Bombina with Discoglossu s and separated these two genera from Alytes, although the tree generated from female response data did not show such a clear result. A. cisternasii females are mostly using some features that are absent in Alytes calls in order to recognize male calls. The two characters, mapped onto the three alternative phylogenetic proposals, did not resolve the trichotomy among the three genera, but suggested that the studied behavioural characters have a clear phylogenetic load. [ABSTRACT FROM AUTHOR]

Alders are nitrogen (N)-fixing riparian trees that promote leaf litter decomposition in streams through their high-nutrient leaf litter inputs. While alders are widespread across Europe, their populations are at risk due to infection by the oomycete Phytophthora ×alni, which causes alder dieback. Moreover, alder death opens a space for the establishment of an aggressive N-fixing invasive species, the black locust (Robinia pseudoacacia). Shifts from riparian vegetation containing healthy to infected alder and, eventually, alder loss and replacement with black locust may alter the key process of leaf litter decomposition and associated microbial decomposer assemblages. We examined this question in a microcosm experiment comparing three types of leaf litter mixtures: one representing an original riparian forest composed of healthy alder (Alnus lusitanica), ash (Fraxinus angustifolia), and poplar (Populus nigra); one with the same species composition where alder had been infected by P. ×alni; and one where alder had been replaced with black locust. The experiment lasted six weeks, and every two weeks, microbially driven decomposition, fungal biomass, reproduction, and assemblage structure were measured. Decomposition was highest in mixtures with infected alder and lowest in mixtures with black locust, reflecting differences in leaf nutrient concentrations. Mixtures with alder showed distinct fungal assemblages and higher sporulation rates than mixtures with black locust. Our results indicate that alder loss and its replacement with black locust may alter key stream ecosystem processes and assemblages, with important changes already occurring during alder infection. This highlights the importance of maintaining heathy riparian forests to preserve proper stream ecosystem functioning., (© 2024. The Author(s).)

Several human activities often result in increased nitrogen (N) and phosphorus (P) inputs to running waters through runoff. Although headwater streams are less frequently affected by these inputs than downstream reaches, the joint effects of moderate eutrophication and global warming can affect the functioning of these ecosystems, which represent two thirds of total river length and thus are of major global relevance. In a microcosm study representing streams from a temperate area (northern Spain), we assessed the combined effects of increased water temperature (10.0, 12.5, and 15.0 °C) and nutrient enrichment (control, high N, high P, and high N + P concentrations) on the key process of leaf litter decomposition (mediated by microorganisms and detritivores) and associated changes in different biological compartments (leaf litter, aquatic hyphomycetes and detritivores). While warming consistently enhanced decomposition rates and associated variables (leaf litter microbial conditioning, aquatic hyphomycete sporulation rate and taxon richness, and detritivore growth and nutrient contents), effects of eutrophication were weaker and more variable: P addition inhibited decomposition, addition of N + P promoted leaf litter conditioning, and detritivore stoichiometry was affected by the addition of both nutrients separately or together. In only a few cases (variables related to detritivore performance, but not microbial performance or leaf litter decomposition) we found interactions between warming and eutrophication, which contrasts with other experiments reporting synergistic effects. Our results suggest that both stressors can importantly alter the functioning of stream ecosystems even when occurring in isolation, although non-additive effects should not be neglected and might require exploring an array of ecosystem processes (not just leaf litter decomposition) in order to be detected., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Epigenetic mechanisms have emerged as an important contributor to tumor development through the modulation of gene expression. Our objective was to identify the methylation profile of the imprinted C19MC and MIR371-3 clusters in patients with non-small cell lung cancer (NSCLC) and to find their potential target genes, as well as to study their prognostic role. DNA methylation status was analyzed in a NSCLC patient cohort ( n = 47) and compared with a control cohort including COPD patients and non-COPD subjects ( n = 23) using the Illumina Infinium Human Methylation 450 BeadChip. Hypomethylation of miRNAs located on chromosome 19q13.42 was found to be specific for tumor tissue. We then identified the target mRNA-miRNA regulatory network for the components of the C19MC and MIR371-3 clusters using the miRTargetLink 2.0 Human tool. The correlations of miRNA-target mRNA expression from primary lung tumors were analyzed using the CancerMIRNome tool. From those negative correlations identified, we found that a lower expression of 5 of the target genes ( FOXF2 , KLF13 , MICA , TCEAL1 and TGFBR2 ) was significantly associated with poor overall survival. Taken together, this study demonstrates that the imprinted C19MC and MIR371-3 miRNA clusters undergo polycistronic epigenetic regulation leading to deregulation of important and common target genes with potential prognostic value in lung cancer.

Amphibians are declining worldwide due to a combination of stressors such as climate change, invasive species, habitat loss, pollution and emergent diseases. Although their losses are likely to have important ecological consequences on the structure and functioning of freshwater ecosystems, this issue has been scarcely explored. We conducted an experiment in three montane streams-where primary production is the main source of energy and carbon-to assess the effects of amphibian disappearance (i.e. presence or absence of the common midwife toad Alytes obstetricans, a common species found in pools of these streams) on several aspects of ecosystem functioning and structure: periphyton biomass and chlorophyll a concentration, algal assemblage structure, and growth of macroinvertebrate grazers. We compared four types of experimental enclosures: (i) without macroinvertebrates or amphibians; (ii) with larvae of the caddisfly Allogamus laureatus; (iii) with A. obstetricans tadpoles; and (iv) with both A. laureatus larvae and A. obstetricans tadpoles. The absence of tadpoles increased periphyton biomass, but did not cause differences on inorganic sediment accrual. The algal assemblage had a higher diversity in the absence of tadpoles, and their characteristic taxa differed from the assemblages in presence of tadpoles. A. laureatus presented higher mass in presence of tadpoles; however, tadpole length was not affected by presence of macroinvertebrates. Our results suggest that presence of tadpoles is a driver of periphyton accrual and assemblage structure, acting as top-down control and with key potential consequences on the functioning of montane stream ecosystems., (© 2022 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.)

Microplastics (MPs) have been recognized as one of the most ubiquitous environmental pollutants globally. They have been found in all ecosystems studied to date, threatening biological diversity, ecosystem functioning and human health. The present study aimed to elucidate the environmental and anthropogenic drivers of MP dynamics in the whole catchment of the Biobío river, one of the largest rivers in South America. MP concentration and characteristics were analysed in 18 sites subjected to different sources of pollution and other human-related impacts. The sampling sites were classified in relation to altitudinal zones (highland, midland and lowland) and ecosystem types (fluvial and reservoir), and different water and territorial environmental variables were further collated and considered for analysis. Seven types of microplastic polymers were identified in the samples analysed, with a catchment mean (±SE) MP concentration of 22 ± 0.4 particles m -3 , and MP presence being significantly higher in lowlands (26 ± 2 particle m -3 ) and in reservoirs (42 ± 14 particle m -3 ). The most abundant type of MP was fragments (84%), with a mean concentration of 37 ± 6 particles m -3 . Overall, MP concentrations were low compared to those found in other studies, with a strong influence of human population size., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Nivolumab (anti-PD-1 antibody) and atezolizumab (anti-PD-L1 antibody) have shown superior survival outcomes and improved adverse effects compared to standard chemotherapy in advanced non-small cell lung cancer (NSCLC) patients. However, the efficacy of both treatments has not been directly compared in clinical trials. This retrospective, single-centre study was performed from June 2015 to December 2020 and included a cohort of 158 previously treated patients with stage IV or recurrent NSCLC who received PD-1 (nivolumab) (n = 89) or PD-L1 (atezolizumab) (n = 69) inhibitors at the Virgen del Rocío Hospital in Seville. The objective response rate (ORR) was 22.5% in the nivolumab group and 14.5% in the atezolizumab group (p = 0.140). Multivariate analysis did not show significant differences between the two groups for PFS and OS (PFS hazard ratio (HR): 0.80, 95% confidence interval (CI): 0.55−1.17, p = 0.260; OS HR: 0.79, 95% CI: 0.52−1.21, p = 0.281). Adverse events of all grades occurred in 68 patients in the nivolumab group (76.4%) and in 34 patients in the atezolizumab group (49.3%) (p < 0.001). Atezolizumab and nivolumab did not show statistically significant differences in survival outcomes in patients with NSCLC, even when stratified by histological subtype (squamous versus nonsquamous). However, the safety analysis suggested a more favourable toxicity profile for atezolizumab.

Purpose: Plakophilin 1 (PKP1) is well-known as an important component of the desmosome, a cell structure specialized in spot-like cell-to-cell adhesion. Although desmosomes have generally been associated with tumor suppressor functions, we recently found that PKP1 is recurrently overexpressed in squamous cell lung cancer (SqCLC) to exert an oncogenic role by enhancing the translation of MYC (c-Myc), a major oncogene. In this study, we aim to further characterize the functional relationship between PKP1 and MYC., Methods: To determine the functional relationship between PKP1 and MYC, we performed correlation analyses between PKP1 and MYC mRNA expression levels, gain/loss of function models, chromatin immunoprecipitation (ChIP) and promoter mutagenesis followed by luciferase assays., Results: We found a significant correlation between the mRNA levels of MYC and PKP1 in SqCLC primary tumor samples. In addition, we found that MYC is a direct transcription factor of PKP1 and binds to specific sequences within its promoter. In agreement with this, we found that MYC knockdown reduced PKP1 protein expression in different SqCLC models, which may explain the PKP1-MYC correlation that we found. Conversely, we found that PKP1 knockdown reduced MYC protein expression, while PKP1 overexpression enhanced MYC expression in these models., Conclusions: Based on these results, we propose a feedforward functional relationship in which PKP1 enhances MYC translation in conjunction with the translation initiation complex by binding to the 5'-UTR of MYC mRNA, whereas MYC promotes PKP1 transcription by binding to its promoter. These results suggest that PKP1 may serve as a therapeutic target for SqCLC., (© 2022. Springer Nature Switzerland AG.)

Microplastics (MPs), a new class of pollutants that pose a threat to aquatic biodiversity, are of increasing global concern. In tandem, the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) causing the disease chytridiomycosis is emerging worldwide as a major stressor to amphibians. We here assess whether synergies exist between this infectious disease and MP pollution by mimicking natural contact of a highly susceptible species (midwife toads, Alytes obstetricans) with a Bd-infected reservoir species (fire salamanders, Salamandra salamandra) in the presence and absence of MPs. We found that MP ingestion increases the burden of infection by Bd in a dose-dependent manner. However, MPs accumulated to a greater extent in amphibians that were not exposed to Bd, likely due to Bd-damaged tadpole mouthparts interfering with MP ingestion. Our experimental approach showed compelling interactions between two emergent processes, chytridiomycosis and MP pollution, necessitating further research into potential synergies between these biotic and abiotic threats to amphibians., (© 2021. The Author(s).)

Litter decomposition is an ecological process of key importance for forest headwater stream functioning, with repercussions for the global carbon cycle. The process is directly and indirectly mediated by microbial decomposers, mostly aquatic hyphomycetes, and influenced by environmental and biological factors such as water temperature and litter quality. These two factors are forecasted to change globally within the next few decades, in ways that may have contrasting effects on microbial-induced litter decomposition: while warming is expected to enhance microbial performance, the reduction in litter quality due to increased atmospheric carbon dioxide and community composition alteration may have the opposite outcome. We explored this issue through a microcosm experiment focused on early microbial-mediated litter decomposition under stream oligotrophic conditions, by simultaneously manipulating water temperature (10 °C and 15 °C) and litter quality (12 broadleaf plant species classified into 4 categories based on initial concentrations of nitrogen and tannins). We assessed potential changes in microbial-mediated litter decomposition and the performance of fungal decomposers (i.e., microbial respiration, biomass accrual, and sporulation rate) and species richness. We found stronger effects of litter quality, which enhanced the performance of microbial decomposers and decomposition rates, than temperature, which barely influenced any of the studied variables. Our results suggest that poorer litter quality associated with global change will have a major repercussion on stream ecosystem functioning., (© 2021. The Author(s).)

Understanding which factors affect the process of leaf litter decomposition is crucial if we are to predict changes in the functioning of stream ecosystems as a result of human activities. One major activity with known consequences on streams is agriculture, which is of particular concern in tropical regions, where forests are being rapidly replaced by crops. While pesticides are potential drivers of reduced decomposition rates observed in agricultural tropical streams, their specific effects on the performance of decomposers and detritivores are mostly unknown. We used a microcosm experiment to examine the individual and joint effects of an insecticide (chlorpyrifos) and a fungicide (chlorothalonil) on survival and growth of detritivores (Anchytarsus, Hyalella and Lepidostoma), aquatic hyphomycetes (AH) sporulation rate, taxon richness, assemblage structure, and leaf litter decomposition rates. Our results revealed detrimental effects on detritivore survival (which were mostly due to the insecticide and strongest for Hyalella), changes in AH assemblage structure, and reduced sporulation rate, taxon richness and microbial decomposition (mostly in response to the fungicide). Total decomposition was reduced especially when the pesticides were combined, suggesting that they operated differently and their effects were additive. Importantly, effects on decomposition were greater for single-species detritivore treatments than for the 3-species mixture, indicating that detritivore species loss may exacerbate the consequences of pesticides of stream ecosystem functioning., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The relationship between detritivore diversity and decomposition can provide information on how biogeochemical cycles are affected by ongoing rates of extinction, but such evidence has come mostly from local studies and microcosm experiments. We conducted a globally distributed experiment (38 streams across 23 countries in 6 continents) using standardised methods to test the hypothesis that detritivore diversity enhances litter decomposition in streams, to establish the role of other characteristics of detritivore assemblages (abundance, biomass and body size), and to determine how patterns vary across realms, biomes and climates. We observed a positive relationship between diversity and decomposition, strongest in tropical areas, and a key role of abundance and biomass at higher latitudes. Our results suggest that litter decomposition might be altered by detritivore extinctions, particularly in tropical areas, where detritivore diversity is already relatively low and some environmental stressors particularly prevalent.

Background: Immune checkpoint inhibitors (ICIs) are currently the standard therapy in advanced non-small cell lung cancer (NSCLC); however, there is no well-established prognostic biomarker. We investigated the relationship between survival outcomes and three peripheral blood biomarkers, including the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and monocyte-to-lymphocyte ratio (MLR), as well as a new score termed the risk blood biomarker (RBB), calculated from the combination of the neutrophil-monocyte-to-lymphocyte ratio (NMLR) and white blood cell count (WBC)., Methods: This study included patients with stage IV or recurrent NSCLC confirmed with programmed death ligand 1 (PD-L1) expression ≥50% who received pembrolizumab monotherapy as first-line treatment at the Virgen del Rocío University Hospital in Seville, Spain. To establish the relationship between baseline peripheral blood biomarkers and survival outcomes, progression free survival (PFS) and overall survival (OS), we used the Kaplan-Meier method and multivariable Cox regression models., Results: A total of 51 patients were included in this study. In multivariate analysis, baseline NLR and PLR showed a strong association with PFS [NLR hazard ratio (HR): 0.19, 95% confidence interval (CI): 0.09-0.44, P<0.001; PLR HR: 0.46, 95% CI: 0.23-0.92, P=0.03] and OS (NLR HR: 0.07, 95% CI: 0.02-0.19, P<0.001; PLR HR: 0.29, 95% CI: 0.13-0.67, P=0.004), and the MLR was associated with OS (MLR HR: 0.34, 95% CI: 0.15-0.76, P=0.01). According to the RBB score, groups with lower scores were associated with superior PFS (group 0: HR: 0.16, 95% CI: 0.06-0.41, P<0.001 and group 1: HR: 0.29, 95% CI: 0.12-0.73, P=0.01) and OS (group 0: HR: 0.04, 95% CI: 0.01-0.17, P<0.001 and group 1: HR: 0.15, 95% CI: 0.05-0.42, P<0.001)., Conclusions: Low baseline NLR, MLR and PLR are significantly associated with better PFS, and low baseline NLR and PLR are associated with better OS. Additionally, we identified three subgroups of patients using the RBB score, and low scores were associated with improved survival outcomes and response to therapy., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/tlcr-21-156). The authors have no conflicts of interest to declare., (2021 Translational Lung Cancer Research. All rights reserved.)

Several studies have examined the transmission dynamics of the novel COVID-19 disease in different parts of the world. Some have reported relationships with various environmental variables, suggesting that spread of the disease is enhanced in colder and drier climates. However, evidence is still scarce and mostly limited to a few countries, particularly from Asia. We examined the potential role of multiple environmental variables in COVID-19 infection rate [measured as mean relative infection rate = (number of infected inhabitants per week / total population) × 100.000) from February 23 to August 16, 2020 across 360 cities of Chile. Chile has a large climatic gradient (≈ 40º of latitude, ≈ 4000 m of altitude and 5 climatic zones, from desert to tundra), but all cities share their social behaviour patterns and regulations. Our results indicated that COVID-19 transmission in Chile was mostly related to three main climatic factors (minimum temperature, atmospheric pressure and relative humidity). Transmission was greater in colder and drier cities and when atmospheric pressure was lower. The results of this study support some previous findings about the main climatic determinants of COVID-19 transmission, which may be useful for decision-making and management of the disease.

Freshwater organisms are often sensitive to pesticides, but their sensitivity varies across different taxa and with pesticide type and action mode, as shown by multiple acute toxicity tests. Such variability hampers predictions about how freshwater ecosystems may be altered by pesticide toxicity, which is especially critical for understudied areas of the world such as the tropics. Furthermore, there is little information about the sensitivity of some organisms that are key components of stream food webs; this is the case of litter-feeding detritivorous invertebrates, which contribute to the fundamental process of litter decomposition. Here, we examined the sensitivity of three common detritivores [Anchytarsus sp. (Coleoptera: Ptilodactylidae), Hyalella sp. (Amphipoda: Hyalellidae) and Lepidostoma sp. (Trichoptera: Lepidostomatidae)] to three pesticides commonly used (the insecticides bifenthrin and chlorpyrifos and the fungicide chlorothalonil) using acute (48 or 96 h) toxicity tests. Our study demonstrates that common-use pesticides provoke the mortality of half their populations at concentrations of 0.04-2.7 μg L -1 . We found that all species were sensitive to the three pesticides, with the highest sensitivity found for chlorpyrifos. Additionally, we used the approach of species sensitivity distributions (SSD) to compare our study species with Daphnia magna and other temperate and tropical invertebrates. We found that the study species were among the most sensitive species to chlorpyrifos and chlorothalonil. Our results suggest that tropical detritivores merit special attention in ecological risk assessment of pesticides and highlight the need for accurate ecotoxicological information from ecologically relevant species in the tropics., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Running waters contribute substantially to global carbon fluxes through decomposition of terrestrial plant litter by aquatic microorganisms and detritivores. Diversity of this litter may influence instream decomposition globally in ways that are not yet understood. We investigated latitudinal differences in decomposition of litter mixtures of low and high functional diversity in 40 streams on 6 continents and spanning 113° of latitude. Despite important variability in our dataset, we found latitudinal differences in the effect of litter functional diversity on decomposition, which we explained as evolutionary adaptations of litter-consuming detritivores to resource availability. Specifically, a balanced diet effect appears to operate at lower latitudes versus a resource concentration effect at higher latitudes. The latitudinal pattern indicates that loss of plant functional diversity will have different consequences on carbon fluxes across the globe, with greater repercussions likely at low latitudes., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

After several decades without maintained responses or long-term survival of patients with lung cancer, novel therapies have emerged as a hopeful milestone in this research field. The appearance of immunotherapy, especially immune checkpoint inhibitors, has improved both the overall survival and quality of life of patients, many of whom are diagnosed late when classical treatments are ineffective. Despite these unprecedented results, a high percentage of patients do not respond initially to treatment or relapse after a period of response. This is due to resistance mechanisms, which require understanding in order to prevent them and develop strategies to overcome them and increase the number of patients who can benefit from immunotherapy. This review highlights the current knowledge of the mechanisms and their involvement in resistance to immunotherapy in lung cancer, such as aberrations in tumor neoantigen burden, effector T-cell infiltration in the tumor microenvironment (TME), epigenetic modulation, the transcriptional signature, signaling pathways, T-cell exhaustion, and the microbiome. Further research dissecting intratumor and host heterogeneity is necessary to provide answers regarding the immunotherapy response and develop more effective treatments for lung cancer.

The expansion of agriculture is particularly worrying in tropical regions of the world, where native forests are being replaced by crops at alarming rates, with severe consequences for biodiversity and ecosystems. However, there is little information about the potential effects of agriculture on the functioning of tropical streams, which is essential if we are to assess the condition and ecological integrity of these ecosystems. We conducted a litter decomposition experiment in streams within a tropical catchment, which were subjected to different degrees of agricultural influence: low (protected area, PA), medium (buffer area, BA) and high (agricultural area, AA). We quantified decomposition rates of litter enclosed within coarse-mesh and fine-mesh bags, which allowed the distinction of microbial and detritivore-mediated decomposition pathways. We used litter of three riparian species representing a gradient in litter quality (Alnus acuminata > Ficus insipida > Quercus bumelioides), and examined detritivore assemblages through the contents of litterbags and benthic samples. We found that the increasing agricultural influence promoted microbial decomposition, probably due to nutrient-mediated stimulation; and inhibited detritivore-mediated and total decomposition because of reduced detritivore numbers, most likely caused by pesticides and sedimentation. Effects were evident for Alnus and Ficus, but not for Quercus, which was barely decomposed across the gradient. Our study provides key evidence about the impact of agriculture on tropical stream ecosystem functioning, which is associated to changes in stream assemblages and may have far-reaching repercussions for global biochemical cycles., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Plant litter decomposition is a key ecosystem process that can be altered by global changes such as biodiversity loss. These effects can be particularly important in detritus-based ecosystems, such as headwater streams, which are mainly fuelled by allochthonous plant litter inputs. However, experiments examining effects of plant diversity on litter decomposition in streams have not reached consensus about which measures of biodiversity are more relevant. We explored the influence of two of these measures, plant species richness (SR; monocultures vs. 3-species mixtures) and phylogenetic distance (PD; species belonging to the same family vs. different families), on leaf litter decomposition and associated processes and variables (nutrient dynamics, fungal biomass and detritivore growth), in a stream microcosm experiment using litter from 9 tree species belonging to 3 families. We found a negative effect of SR on decomposition (which contradicted the results of previous experiments) but a positive effect on fungal biomass. While PD did not affect decomposition, both SR and PD altered nutrient dynamics: there was greater litter and detritivore N loss in low-PD mixtures, and greater litter P loss and detritivore P gain in monocultures. This suggested that the number of species in mixtures and the similarity of their traits both modulated nutrient availability and utilization by detritivores. Moreover, the greater fungal biomass with higher SR could imply positive effects on detritivores in the longer term. Our results provide new insights of the functional repercussions of biodiversity loss by going beyond the often-explored relationship between SR and decomposition, and reveal an influence of plant species phylogenetic relatedness on nutrient cycling that merits further investigation.

Plakophilin 1 (PKP1) is a member of the arm-repeat (armadillo) and plakophilin gene families and it is an essential component of the desmosomes. Although desmosomes have generally been associated with tumor suppressor functions, we have consistently observed that PKP1 is among the top overexpressed proteins in squamous cell lung cancer. To explore this paradox, we developed in vivo and in vitro functional models of PKP1 gain/loss in squamous cell lung cancer. CRISPR-Cas9 PKP1 knockout severely impaired cell proliferation, but it increased cell dissemination. In addition, PKP1 overexpression increased cell proliferation, cell survival, and in vivo xenograft engraftment. We further investigated the molecular mechanism of the mainly oncogenic function of PKP1 by combining transcriptomics, proteomics, and protein-nucleic acid interaction assays. Interestingly, we found that PKP1 enhances MYC translation in collaboration with the translation initiation complex by binding to the 5'-UTR of MYC mRNA. We propose PKP1 as an oncogene in SqCLC and a novel posttranscriptional regulator of MYC. PKP1 may be a valuable diagnostic biomarker and potential therapeutic target for SqCLC. Importantly, PKP1 inhibition may indirectly target MYC, a primary anticancer target.

Genomic imprinting is a process that involves one gene copy turned-off in a parent-of-origin-dependent manner. The regulation of imprinted genes is broadly dependent on promoter methylation marks, which are frequently associated with both oncogenes and tumor suppressors. The purpose of this study was to assess the DNA methylation patterns of the imprinted solute-carrier family 22 member 18 ( SLC22A18) and SLC22A18 antisense (SLC22A18AS) genes in non-small cell lung cancer (NSCLC) patients to study their relevance to the disease. We found that both genes were hypomethylated in adenocarcinoma and squamous cell carcinoma patients. Due to this imprinting loss, SLC22A18 and SLC22A18AS were found to be overexpressed in NSCLC tissues, which is significantly more evident in lung adenocarcinoma patients. These results were validated through analyses of public databases of NSCLC patients. The reversed gene profile of both genes was achieved in vitro by treatment with ademetionine. We then showed that high SLC22A18 and SLC22A18AS expression levels were significantly associated with worsening disease progression. In addition, low levels of SLC22A18AS were also correlated with better overall survival for lung adenocarcinoma patients. We found that SLC22A18 and SLC22A18AS knockdown inhibits cell proliferation in vitro. All these results suggest that both genes may be useful as diagnostic and prognostic biomarkers in NSCLC, revealing novel therapeutic opportunities.

Fungicides can reach streams through runoff or adhered to leaf litter, and have the potential to adversely affect processes such as litter decomposition and associated communities. This study investigated the effects of chlorothalonil, a widely used fungicide, on litter decomposition, detritivorous invertebrates (larvae of the insect Sericostoma pyrenaicum) and aquatic hyphomycetes (AHs), using stream microcosms. We considered the single and combined effects of two exposure modes: waterborne fungicide (at two concentrations: 0.125 μg L -1 and 1.25 μg L -1 ) and litter previously sprayed with the fungicide (i.e., pre-treated litter, using the application dose concentration of 1250 μg L -1 ). We also assessed whether fungicide effects on invertebrates, AHs and decomposition varied among litter types (i.e., different plant species), and whether plant diversity mitigated any of those effects. Invertebrate survival and AH sporulation rate and taxon richness were strongly reduced by most combinations of fungicide exposure modes; however, invertebrates were not affected by the low waterborne concentration, whereas AHs suffered the highest reduction at this concentration. Total decomposition was slowed down by both exposure modes, and microbial decomposition was reduced by litter pre-treatment, while the waterborne fungicide had different effects depending on plant species. In general, with the exception of microbial decomposition, responses varied little among litter types. Moreover, and contrary to our expectation, plant diversity did not modulate the fungicide effects. Our results highlight the severity of fungicide inputs to streams through effects on invertebrate and microbial communities and ecosystem functioning, even in streams with well-preserved, diverse riparian vegetation., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The marine ecosystem of the Chilean Patagonia is considered structurally and functionally unique, because it is the transition area between the Antarctic climate and the more temperate Pacific region. However, due to its remoteness, there is little information about Patagonian marine biodiversity, which is a problem in the face of the increasing anthropogenic activity in the area. The aim of this study was to analyze community patterns and environmental characteristics of scavenging crustaceans in the Chilean Patagonian Sea, as a basis for comparison with future situations where these organisms may be affected by anthropogenic activities. These organisms play a key ecological role in marine ecosystems and constitute a main food for fish and dolphins, which are recognized as one of the main tourist attractions in the study area. We sampled two sites (Puerto Cisnes bay and Magdalena sound) at four different bathymetric strata, recording a total of 14 taxa that included 7 Decapoda, 5 Amphipoda, 1 Isopoda and 1 Leptostraca. Taxon richness was low, compared to other areas, but similar to other records in the Patagonian region. The crustacean community presented an evident differentiation between the first stratum (0-50 m) and the deepest area in Magdalena sound, mostly influenced by Pseudorchomene sp. and a marked environmental stratification. This species and Isaeopsis sp. are two new records for science. The discovery of undescribed species evidences that this region needs further studies exploring its biodiversity, which is most likely being already impacted by anthropogenic pressure.

Microplastics (MPs) are contaminants of increasing concern due to their abundance, ubiquity and persistence over time. However, knowledge about MP distribution in fresh waters and their effects on freshwater organisms is still scarce, and there is virtually no information about their potential influence on ecosystem functioning. We used a microcosm experiment to examine the effects of MPs (fluorescent, 10-μm polystyrene microspheres) at different concentrations (from 0 to 10 3 particles mL -1 ) on leaf litter decomposition (a key process in stream ecosystems) and associated organisms (the caddisfly detritivore Sericostoma pyrenaicum), and the extent to which MPs were attached to leaf litter and ingested and egested by detritivores, thus assessing mechanisms of MP trophic transfer. We found that MPs caused detritivore mortality (which increased 9-fold at the highest concentration) but did not affect their growth. Analysis of fluorescence in samples suggested that MPs were rapidly ingested (most likely through ingestion of particles attached to leaf litter) and egested. Leaf litter decomposition was reduced as a result of increasing MP concentrations; the relationship was significant only in the presence of detritivores, but microbially-mediated decomposition showed a similar trend. Our findings provide novel evidence of harmful effects of MPs on aquatic insects and stream ecosystem functioning, and highlight the need for the standardization of methods in future experiments with MPs in order to allow comparisons and generalizations., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Microplastics (MPs) are contaminants of increasing concern; they are abundant, ubiquitous and persistent over time, representing potential risks for organisms and ecosystems. However, such risks are still virtually unknown for amphibians, despite the particular attention that these organisms often receive because of their global decline. We examined the effects of MPs (fluorescent, 10-μm polystyrene microspheres) at different concentrations (from 0 to 10 3 particles mL -1 ) on tadpoles of the common midwife toad, Alytes obstetricans, using a microcosm experiment. We assessed MP effects on tadpole feeding, growth and body condition, as well as their ingestion and egestion of MPs (estimated through fluorescence). Additionally, we explored whether MPs became attached to periphyton (the main food source for these tadpoles, thus potentially representing a major way of MP ingestion), and the effect of MPs on periphyton growth (which may translate into altered freshwater ecosystem functioning). Our results showed significant effects on all the examined variables, and caused tadpole mortality at the highest concentration; also, fluorescence indicated the presence of MPs in tadpoles, tadpole faeces and periphyton. This suggests that MPs can be an important source of stress for amphibians in addition to other pollutants, climate change, habitat loss or chytrid infections, and that amphibians can be a major transfer path for MPs from freshwater to terrestrial ecosystems., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Biodiversity loss is occurring globally at unprecedented rates, altering the functioning of the Earth's ecosystems. Multiple processes are often key components of ecosystem functioning, but it is unclear how biodiversity loss affects ecosystem multifunctionality (i.e., the ability of ecosystems to maintain multiple processes simultaneously). This is particularly true for some ecosystem types such as streams, which have been understudied, despite their key role in global biogeochemical cycles and their serious impairment by the widespread loss of riparian vegetation as a result of global change. Using a microcosm experiment, we tested whether losing riparian plant diversity affected stream multifunctionality, taking into account nine key processes related to litter decomposition, animal biomass production, and nutrient cycling, and simulating plant species loss from four to one in the presence or absence of litter-feeding detritivores. Multifunctionality increased with plant diversity in the presence of detritivores and decreased in their absence, evidencing a key role of detritivores in biodiversity-ecosystem-functioning (BEF) relationships. Moreover, by exploring effects of plant diversity on each process individually we were able to reveal potential mechanisms underlying BEF relationships; for example, effects of plant diversity on nutrient cycling occurred at least partly via indirect nutrient transfer, and were possibly accompanied by changes in microbial stoichiometry. Such mechanisms were unnoticeable when examining multifunctionality metrics, suggesting that individual processes provide crucial information to understand how stream ecosystem functioning is impaired by biodiversity loss., (© 2019 by the Ecological Society of America.)

Tropical forests are declining at unprecedented rates in favour of agriculture, and streams can be severely impacted due to effects of multiple stressors that have rarely been considered together in tropical studies. We studied the effects of multiple stressors associated with agricultural practices (pesticide toxicity, nutrient enrichment and habitat alteration-quantified as TUmax, soluble reactive phosphorus concentration and sedimentation, respectively) on macroinvertebrate communities in a tropical catchment in Panama (13 stream sites sampled in 20 occasions from 2015 to 2017, with 260 samples in total). We examined how macroinvertebrate abundance, taxonomic richness, community composition and biotic indices (SPEAR and BMWP/PAN, which were specifically designed to detect pesticide toxicity and nutrient enrichment, respectively) varied depending on the studied stressors, considering their single and combined effects. Our analyses revealed significant effects of the studied stressors on macroinvertebrate communities, with two particular results that merit further attention: (1) the fact that pesticide toxicity affected BMWP/PAN, but not SPEAR, possibly because the former had been adapted for local fauna; and (2) that most stressors showed antagonistic interactions (i.e., lower combined effects than expected from their individual effects). These results highlight the need for toxicity bioassays with tropical species that allow adaptations of biotic indices, and of observational and manipulative studies exploring the combined effects of multiple stressors on tropical macroinvertebrate communities and ecosystems, in order to predict and manage future anthropogenic impacts on tropical streams., Competing Interests: The authors have declared that no competing interests exist.

Antarctic and Subantarctic lakes are unique ecosystems with relatively simple food webs, which are likely to be strongly affected by climate warming. While Antarctic freshwater invertebrates are adapted to extreme environmental conditions, little is known about the factors determining their current distribution and to what extent this is explained by biogeography or climate. We explored the distribution of freshwater crustaceans (one of the most abundant and diverse group of organisms in Antarctic and Subantarctic lakes) across four biogeographic provinces (Continental Antarctic, CA; Maritime Antarctic, MA; Subantarctic islands, SA; and Southern Cool Temperate, SCT) based on the literature, predicting that species distribution would be determined by biogeography, spatial autocorrelation among regions (in relation to dispersal) and climate. We found that variation in species composition was largely explained by the joint effect of spatial autocorrelation and climate, with little effect of biogeography - only regions within the SA province had a clearly distinct species composition. This highlights a plausible main influence of crustacean dispersal - mainly through migratory seabirds - and suggests that some regions will be more affected by climate warming than others, possibly in relation to the existence of nearby sources of colonists.

Introduction of alien fish is a major problem for the conservation of amphibians inhabiting originally fishless mountain streams. While fish eradication programs in lakes and ponds have proven successful for the recovery of amphibian populations, there is no such information for stream-dwelling amphibians, possibly because fish removal from streams is difficult and costly. Here, we show the first case of successful recovery of a stream-dwelling amphibian (Rana iberica) in a mountain area of central Spain, following eradication of introduced brook trout (Salvelinus fontinalis) and native brown trout (Salmo trutta) translocated from downstream reaches by local anglers. Electrofishing for 12 consecutive years eradicated both fish species in the introduced area, and allowed the recovery of the R. iberica population as a result of natural recolonization from nearby streams and reintroduction of captive-reared individuals. Our results demonstrate how electrofishing can be a costly but effective method for the eradication of introduced fish and the conservation of stream-dwelling amphibians., Competing Interests: The authors have declared that no competing interests exist.

Climate change and infectious disease by the chytrid fungus Batrachochytrium dendrobatidis (Bd) are major drivers of amphibian extinctions, but the potential interactions of these two factors are not fully understood. Temperature is known to influence (1) the infectivity, pathogenicity and virulence of Bd; (2) host-parasite dynamics, especially when both hosts and parasites are ectothermic organisms exhibiting thermal sensitivities that may or may not differ; and (3) amphibian vulnerability to extinction depending on their heat tolerance, which may decrease with infection. Thus, in a global warming scenario, with rising temperatures and more frequent and extreme weather events, amphibians infected by Bd could be expected to be more vulnerable if temperatures approach their critical thermal maximum (CTmax). However, it is also possible that predicted high temperatures could clear the Bd infection, thus enhancing amphibian survival. We tested these hypotheses by measuring CTmax values of Bd-infected and Bd-free aquatic tadpoles and terrestrial toadlets/juveniles of the common midwife toad (Alytes obstetricans) and examining whether exposure of A. obstetricans individuals to peak temperatures reaching their CTmax clears them from Bd infection. We show that (1) Bd has a wide thermal tolerance range; (2) Bd is capable of altering the thermal physiology of A. obstetricans, which is stage-dependent, lowering CTmax in tadpoles but not in toadlets; and (3) Bd infection is not cleared after exposure of tadpoles or toadlets to CTmax. Living under climatic change with rising temperatures, the effect of Bd infection might tip the balance and lead some already threatened amphibian communities towards extinction., Competing Interests: This study was supported by Banco Santander. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Global patterns of biodiversity have emerged for soil microorganisms, plants and animals, and the extraordinary significance of microbial functions in ecosystems is also well established. Virtually unknown, however, are large-scale patterns of microbial diversity in freshwaters, although these aquatic ecosystems are hotspots of biodiversity and biogeochemical processes. Here we report on the first large-scale study of biodiversity of leaf-litter fungi in streams along a latitudinal gradient unravelled by Illumina sequencing. The study is based on fungal communities colonizing standardized plant litter in 19 globally distributed stream locations between 69°N and 44°S. Fungal richness suggests a hump-shaped distribution along the latitudinal gradient. Strikingly, community composition of fungi was more clearly related to thermal preferences than to biogeography. Our results suggest that identifying differences in key environmental drivers, such as temperature, among taxa and ecosystem types is critical to unravel the global patterns of aquatic fungal diversity., (Copyright © 2019 Elsevier B.V. All rights reserved.)

River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth's biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented "next-generation biomonitoring" by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale.

Understanding how biodiversity loss influences plant litter decomposition-that is, the biologically mediated conversion of coarse to fine particulate organic matter-is crucial to predict changes in the functioning of many stream ecosystems, where detrital food webs are dominant. Rates of litter decomposition are influenced by detritivore diversity, but the mechanisms behind this relationship are uncertain. As differences in detritivore body size are a major determinant of interspecific interactions, they should be key for predicting effects of detritivore diversity on decomposition. To explore this question, we manipulated detritivore diversity and body size simultaneously in a microcosm experiment using two small (Leuctra geniculata and Lepidostoma hirtum) and two large detritivore species (Sericostoma pyrenaicum and Echinogammarus berilloni) in all possible 1-, 2- and 4-species combinations, and litter discs of Alnus glutinosa. We expected that larger species would facilitate smaller species through the production of smaller litter fragments, resulting in faster decomposition and greater growth of smaller species in polycultures containing species of different body size. To examine this hypothesis, we used a set of "diversity-interaction" models that explored how decomposition was affected by different interspecific interactions and the role of body size, and quantified the magnitude of such effect through ratios of decomposition rates and detritivore growth between polycultures and monocultures. We found a clear positive effect of detritivore diversity on decomposition, which was mainly explained by facilitation and niche partitioning. Facilitation of small animals by larger ones was evidenced by a 12% increase in decomposition rates in polycultures compared to monocultures and the higher growth (20%) of small species, which partly fed on fine particulate organic matter produced by larger animals. When the large species were together in polycultures, decomposition was enhanced by 19%, but there were no changes in growth; niche partitioning was a plausible mechanism behind the increase in decomposition rates, as both species fed on different parts of litter discs, only one species being able to eat less palatable parts. Our study demonstrates that interspecific differences in body size should be taken into account in diversity-decomposition studies. Future studies should also consider differences in species' vulnerability to extinction depending on body size and how this might affect ecosystem functioning in different scenarios of detritivore diversity and more complex food webs., (© 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society.)