Transcriptomic Analysis Reveals Insights on Male Infertility in Octopus maya Under Chronic Thermal Stress

Octopus maya endemic to the Yucatan Peninsula, Mexico, is an ectotherm organism particularly temperature-sensitive. Studies in O. maya females show that temperatures above 27°C reduce the number of eggs per spawn, fertilization rate and the viability of embryos. High temperatures also reduce the male reproductive performance and success. However, the molecular mechanisms are still unknown. The transcriptomic profiles of testes from thermally stressed (30°C) and not stressed (24°C) adult male octopuses were compared, before and after mating to understand the molecular bases involved in the low reproductive performance at high temperature. The testis paired-end cDNA libraries were sequenced using the Illumina MiSeq platform. Then, the transcriptome was assembled de novo using Trinity software. A total of 53,214,611 high-quality paired reads were used to reconstruct 85,249 transcripts and 77,661 unigenes with an N50 of 889 bp length. Later, 13,154 transcripts were annotated implementing Blastx searches in the UniProt database. Differential expression analysis revealed 1,881 transcripts with significant difference among treatments. Functional annotation and pathway mapping of differential expressed transcripts revealed significant enrichment for biological processes involved in spermatogenesis, gamete generation, germ cell development, spermatid development and differentiation, response to stress, inflammatory response and apoptosis. Remarkably, the transcripts encoding genes such as ZMYND15, KLHL10, TDRD1, TSSK2 and DNAJB13, which are linked to male infertility in other species, were differentially expressed among the treatments. The expression levels of these key genes, involved in sperm motility and spermatogenesis were validated by quantitative real-time PCR. The results suggest that the reduction in male fertility at high temperature can be related to alterations in spermatozoa development and motility

Identification of the Gene sxtA (Domains sxtA1 and sxtA4) in Mexican Strains of Gymnodinium catenatum (Dinophyceae) and Their Evolution

Saxitoxin (STX) and its analogs are a broad group of natural neurotoxic alkaloids, commonly known as paralytic shellfish toxins. SxtA is the initial gene in the biosynthesis of saxitoxin. It has been proposed that the genes for STX biosynthesis had a bacterial origin and were acquired in the dinoflagellates by a horizontal gene transfer (HGT). In Gymnodinium catenatum, the origin of the STX genes is not well established. In this paper, we sequenced sxtA gene (domains sxtA1 and sxtA4) and determined the gene copy number in the genome in four Mexican strains of G. catenatum. We compare them with sequences of G. catenatum, Pyrodinium bahamense, and Alexandrium spp. from other geographic regions, and non-toxic producing dinoflagellates. Amplifications were performed for domains sxtA1 and sxtA4 from strains of G. catenatum and the phylogenetic analyses was done by maximum likelihood and Bayesian inference. The copy number determination was carried out using qPCR. The phylogenetic tree of domain sxtA4 showed the formation of two clades where G. catenatum sequences separated from the Alexandrium/Pyrodinium clade. The domain sxtA1 formed a higher number of clades than sxtA4. Sequences of G. catenatum were grouped together with sequences of Alexandrium. Dinoflagellates sequences that do not produce saxitoxin formed a separate clade. The gene copy number was 64 ± 30 and 110 ± 50 copies of sxtA1 and sxtA4 respectively. The identification of the gene sxtA of G. catenatum shows that the sequences are similar to those of Alexandrium species with low variations between species. These results may indicate that the acquisition of the gene sxtA was an early HGT event in the evolution of dinoflagellates. The possible loss of the ability to produce STX in some species suggests that the HGT from Alexandrium species toward G. catenatum is not possible

Dos biomarcadores de la plasticidad de la expresión génica en corales Pocillopora del arrecife Carrizales, Pacífico Tropical Mexicano

Background. Gene expression (GE) plasticity is an acclimation response that allows organisms to adjust rapidly to environmental changes, providing an adaptive advantage. GE biomarkers are emerging as a valua-ble tool for linking the organism’s physiological plasticitywith the synergetic effects of large-scale climatic conditions and local impacts such as temperature and nutrients. Objectives. In this study, we investigate the GE plasticity of the 70-kDa heat shock protein (hsp70) and the carbonic anhydrase enzyme (CA) to confirm the ability of those two genes as biomarkers of the Cellular Stress Response and Cellular Homeostasis Res-ponse, respectively. Methods. Using qPCR, we evaluate the GE plasticity of coral colonies from Pocillopora capitata, Pocillopora damicornis,and Pocillopora verrucosa at the Carrizales reef (Colima coast of Mexico) naturally exposed to environmental changes in the Sea Surface Temperature (SST), productivity and nutrients using the cellular density of Symbiodiniaceae and chlorophyll content as health indices. Results. Our results clearly show GE plasticity in the hsp70 for Pocillopora verrucosa and Pocillopora damicornis related to a daily environmental change in temperature and nutrients. On the other hand, the CA gene expression shows no change in response to daily variations. However, there was a significantly high expression of CA and a lower expression of hsp70 in Pocillopora capitata. Furthermore, we found no significant differences in the health in-dices, suggesting some degree of physiological plasticity in Pocillopora corals like its extensive morphological plasticity that could reflect different adaptation capacities to low temperatures and high nutrients during the spring season in the central Mexican Pacific. Conclusions. Evaluating the phenotypic plasticity (morphology and molecular physiology) could help identify coral colonies with a more significant potential to survive en-vironmental stressors. The latter is an essential consideration for managing, conserving, and restoring coral reefs in the Mexican Pacific.Antecedentes. La plasticidad de la expresión génica (GE) es una respuesta inmediata de aclimatación al cambio ambiental que puede proporcionar una ventaja adaptativa. Los biomarcadores de GE están emer-giendo como una herramienta valiosa para vincular la plasticidad fisiológica del organismo con los efectos sinérgicos del cambio climático y el impacto local como la temperatura y nutrientes. Objetivos. Investigamos la plasticidad de la expresión de genes que codifican para la proteína de choque térmico de 70-kDa (hsp70) y la enzima anhidrasa carbónica (CA) para confirmar su utilidad como biomarcadores de la respuesta de estrés y de homeostasis celular, respectivamente. Métodos. Evaluamos la GE mediante qPCR en colonias de corales Pocilloporacapitata, Pocillopora damicornis y Pocillopora verrucosa del arrecife Carrizales (Colima, México) expuestas a un cambio natural en la temperatura de la superficie del mar (SST), productividad pri-maria y nutrientes utilizando la densidad de Symbiodiniaceae y el contenido de clorofila como indicadores de salud. Resultados. La plasticidad de la GE de hsp70 en Pocillopora damicornis y Pocillopora verrucosa se asocia con la variación diaria de temperatura y nutrientes, mientras que el gen de la CA no muestra cambios de expresión relacionada con esta variabilidad. Sin embargo, en Pocillopora capitata se encontró una expresión significativamente mayor de CA y una menor expresión de hsp70. Estos resultados reflejan un grado de plasticidad fisiológica en corales Pocillopora similar a la extensa plasticidad morfológica dentro de este género, lo que podría sugerir diferentes capacidades de adaptación a la temporada primave-ral de bajas temperaturas y alto contenido de nutrientes en la región. Conclusiones. Evaluar la plasticidad fenotípica (morfología y fisiolo-gía molecular) podría ser útil para identificar colonias de corales con un mayor potencial de sobrevivencia al estrés ambiental. Lo anterior resulta relevante para la conservación, manejo y restauración de los arrecifes de coral del Pacífico mexicano.   &nbsp

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Individual Pattern Response to CO₂-Induced Acidification Stress in <i>Haliotis rufescens</i> Suggests Stage-Specific Acclimatization during Its Early Life History

The red abalone Haliotis rufescens is a pivotal marine resource in the context of worldwide abalone aquaculture. However, the species has been listed as critically endangered partly because of the life-history massive mortalities associated with habitat climate changes, including short- and long-term ocean acidification. Because abalone survival depends on its early life history success, figuring out its vulnerability to acidification is the first step to establishing culture management strategies. In the present study, red abalone embryos were reared under long-term CO2-induced acidification (pH 7.8 and 7.6) and evaluated. The impairment prevalence was assessed during their larval stages, considering the developmental success, growth and calcification. The result in the stage-specific disturbance suggests that the body abilities evaluated are at the expense of their development stages, of which the critical threshold is found under −0.4 pH units. Finally, the settlement was short-term stressed, displaying the opposite to that observed in the long-term acidification. Thus, the early life history interacts through multiple pathways that may also depend on the acidification challenge (i.e., short or long term). Understanding the tolerance limits and pathways of the stress response provides valuable insights for exploring the vulnerability of H. rufescens to ocean acidification

Anti-oxidant defence mechanisms and oxidant damage indicators measured in adults of Octopus maya exposed at optimal (24°C) and high (30°C) temperatures

There is the raw data of the evaluations of effects of temperature on males and females of Octopus maya acclimated for 30 d at 24 and 30°C. Data here are: 1. Routine metabolic rates measured in open respirometers during 24h, (RMR24h), without values, used to LMR data 2. The low oxygen consumption data (LMR) obtained from 20% lower quartile data distribution of the RMR 24h 3. High metabolic rate (HMR) measured in animals exposed to 35°C for 5 min in an intermittent respirometer. 4. Values of Q10 calculated with LMR, RMR 24h and HMR data 5. Data of activities of Catalase (CAT), superoxide dismutase (SOD), total glutathione (GSH), lipoperoxidation (LPO), Carbonylation (PO), total protein, acetyl-cholinesterase (AChE), and carboxylesterase (CbE) of hearts and muscle of males and females of O. maya. Abstract Since thermal stress enhances the energy demands, it is possible to hypothesize that the harmful effects of high temperatures observed in cephalopods are the result of the limited capacity of adults to channel more energy than those that the reproductive activity demands. In this sense, the present study was designed to know how thermal stress modulates the energy physiology of Octopus maya adults, evaluated through the relationship between temperature, respiratory metabolism (measured as thermal metabolic scope: TMS), antioxidant defence mechanisms (ANTIOX) and oxidant damage indicators (ODI). Sixty-seven males and females of O. maya were individually distributed in two different temperatures of 24, and 30°C. TMS resulted lower in females and males acclimated to 30°C than in animals maintained at 24°C. At the same time, higher values of ANTIOX and ODI were registered in the branchial hearts than in muscle arms and both octopus males and females acclimated at 30 than 24°C. Octopus Carboxyl-esterase (CbE) and acetylcholinesterase (AChE) were not affected by the acclimation temperature and by sex; however higher values in the branchial hearts than the muscle of those enzymes were observed. Results obtained in the present study demonstrated in adults of O. maya that 30°C is a temperature where animals are in a limit of energy production, probably as a result of the incapacity of animals to transport oxygen to mitochondria. Although the animals are adapted to satisfy their basic energy requirements at 30 °C, it is not enough to cover all the demands energy needed of reproduction. At 30°C, oxidative stress is present explaining the reduction in the production of eggs, viable sperm and therefore in the quality of the progeny

Thermal metabolic scope measured in adults of Octopus maya exposed at optimal (24°C) and high (30°C) temperatures

There is the raw data of the evaluations of effects of temperature on males and females of Octopus maya acclimated for 30 d at 24 and 30°C. Data here are: 1. Routine metabolic rates measured in open respirometers during 24h, (RMR24h), without values, used to LMR data 2. The low oxygen consumption data (LMR) obtained from 20% lower quartile data distribution of the RMR 24h 3. High metabolic rate (HMR) measured in animals exposed to 35°C for 5 min in an intermittent respirometer. 4. Values of Q10 calculated with LMR, RMR 24h and HMR data 5. Data of activities of Catalase (CAT), superoxide dismutase (SOD), total glutathione (GSH), lipoperoxidation (LPO), Carbonylation (PO), total protein, acetyl-cholinesterase (AChE), and carboxylesterase (CbE) of hearts and muscle of males and females of O. maya. Abstract Since thermal stress enhances the energy demands, it is possible to hypothesize that the harmful effects of high temperatures observed in cephalopods are the result of the limited capacity of adults to channel more energy than those that the reproductive activity demands. In this sense, the present study was designed to know how thermal stress modulates the energy physiology of Octopus maya adults, evaluated through the relationship between temperature, respiratory metabolism (measured as thermal metabolic scope: TMS), antioxidant defence mechanisms (ANTIOX) and oxidant damage indicators (ODI). Sixty-seven males and females of O. maya were individually distributed in two different temperatures of 24, and 30°C. TMS resulted lower in females and males acclimated to 30°C than in animals maintained at 24°C. At the same time, higher values of ANTIOX and ODI were registered in the branchial hearts than in muscle arms and both octopus males and females acclimated at 30 than 24°C. Octopus Carboxyl-esterase (CbE) and acetylcholinesterase (AChE) were not affected by the acclimation temperature and by sex; however higher values in the branchial hearts than the muscle of those enzymes were observed. Results obtained in the present study demonstrated in adults of O. maya that 30°C is a temperature where animals are in a limit of energy production, probably as a result of the incapacity of animals to transport oxygen to mitochondria. Although the animals are adapted to satisfy their basic energy requirements at 30 °C, it is not enough to cover all the demands energy needed of reproduction. At 30°C, oxidative stress is present explaining the reduction in the production of eggs, viable sperm and therefore in the quality of the progeny

Gene expression plasticity in Pocillopora corals from 2 locations on the Carrizales Reef, Pacific coast of Mexico

The greatest threat scleractinian corals face today is accelerated climate change. Assuming that most scleractinians are incapable of genetic adaptation to rapid global changes, the alternative response would be phenotypic plasticity, which is classically described as acclimatization. With the purpose of establishing a baseline for the study of acclimatization in corals of the Pacific coast of Mexico, we assessed the molecular and physiological response of 36 colonies of 3 Pocillopora morphospecies (Pocillopora cf. capitata, Pocillopora cf. damicornis, and Pocillopora cf. verrucosa) located at 2 sites (east and west) on Carrizales Reef. Our results show higher incidence of light and chlorophyll concentrations in seawater samples from the west side, suggesting the presence of at least 2 microenvironments with more and less light in the reef. In response, coral morphospecies from the west side showed higher gene expression and significant differences in pigment concentrations, endosymbiont densities, and metabolic markers (RNA, DNA, and proteins). Given the present concern about the future of coral reefs, we consider that the present study could be used as a baseline for the study of the physiological and molecular plasticity of Pocillopora corals in Mexican waters, so conservation strategies could be developed for key morphospecies in coral reefs on the Pacific coast of Mexico