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1.
Proc Natl Acad Sci U S A ; 120(42): e2305712120, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37812723

RESUMO

Despite passing routine laboratory tests for semen quality, bulls used in artificial insemination exhibit significant variation in fertility. Routine analysis of fertility data identified a dairy bull with extreme subfertility (10% pregnancy rate). To characterize the subfertility phenotype, a range of in vitro, in vivo, and molecular assays were carried out. Sperm from the subfertile bull exhibited reduced motility and severely reduced caffeine-induced hyperactivation compared to controls. Ability to penetrate the zona pellucida, cleavage rate, cleavage kinetics, and blastocyst yield after IVF or AI were significantly lower than in control bulls. Whole-genome sequencing from semen and RNA sequencing of testis tissue revealed a critical mutation in adenylate kinase 9 (AK9) that impaired splicing, leading to a premature termination codon and a severely truncated protein. Mice deficient in AK9 were generated to further investigate the function of the gene; knockout males were phenotypically indistinguishable from their wild-type littermates but produced immotile sperm that were incapable of normal fertilization. These sperm exhibited numerous abnormalities, including a low ATP concentration and reduced motility. RNA-seq analysis of their testis revealed differential gene expression of components of the axoneme and sperm flagellum as well as steroid metabolic processes. Sperm ultrastructural analysis showed a high percentage of sperm with abnormal flagella. Combined bovine and murine data indicate the essential metabolic role of AK9 in sperm motility and/or hyperactivation, which in turn affects sperm binding and penetration of the zona pellucida. Thus, AK9 has been found to be directly implicated in impaired male fertility in mammals.


Assuntos
Adenilato Quinase , Infertilidade , Sêmen , Animais , Bovinos , Feminino , Masculino , Camundongos , Gravidez , Adenilato Quinase/genética , Adenilato Quinase/metabolismo , Fertilidade , Mamíferos , Sêmen/metabolismo , Análise do Sêmen , Motilidade dos Espermatozoides , Espermatozoides/metabolismo
2.
Proc Natl Acad Sci U S A ; 119(21): e2200713119, 2022 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-35594402

RESUMO

Body size covaries with population dynamics across life's domains. Metabolism may impose fundamental constraints on the coevolution of size and demography, but experimental tests of the causal links remain elusive. We leverage a 60,000-generation experiment in which Escherichia coli populations evolved larger cells to examine intraspecific metabolic scaling and correlations with demographic parameters. Over the course of their evolution, the cells have roughly doubled in size relative to their ancestors. These larger cells have metabolic rates that are absolutely higher, but relative to their size, they are lower. Metabolic theory successfully predicted the relations between size, metabolism, and maximum population density, including support for Damuth's law of energy equivalence, such that populations of larger cells achieved lower maximum densities but higher maximum biomasses than populations of smaller cells. The scaling of metabolism with cell size thus predicted the scaling of size with maximum population density. In stark contrast to standard theory, however, populations of larger cells grew faster than those of smaller cells, contradicting the fundamental and intuitive assumption that the costs of building new individuals should scale directly with their size. The finding that the costs of production can be decoupled from size necessitates a reevaluation of the evolutionary drivers and ecological consequences of biological size more generally.


Assuntos
Ecologia , Escherichia coli , Evolução Biológica , Escherichia coli/genética , Escherichia coli/metabolismo
3.
Proc Natl Acad Sci U S A ; 119(12): e2119010119, 2022 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-35298339

RESUMO

Horizontal gene transfer (HGT) is important for microbial evolution, yet we know little about the fitness effects and dynamics of horizontally transferred genetic variants. In this study, we evolve laboratory populations of Helicobacter pylori, which take up DNA from their environment by natural transformation, and measure the fitness effects of thousands of transferred genetic variants. We find that natural transformation increases the rate of adaptation but comes at the cost of significant genetic load. We show that this cost is circumvented by recombination, which increases the efficiency of selection by decoupling deleterious and beneficial genetic variants. Our results show that adaptation with HGT, pervasive in natural microbial populations, is shaped by a combination of selection, recombination, and genetic drift not accounted for in existing models of evolution.


Assuntos
Transferência Genética Horizontal , Helicobacter pylori , Transferência Genética Horizontal/genética , Helicobacter pylori/genética
4.
Proc Natl Acad Sci U S A ; 119(27): e2116197119, 2022 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-35767643

RESUMO

The majority of viruses within the gut are obligate bacterial viruses known as bacteriophages (phages). Their bacteriotropism underscores the study of phage ecology in the gut, where they modulate and coevolve with gut bacterial communities. Traditionally, these ecological and evolutionary questions were investigated empirically via in vitro experimental evolution and, more recently, in vivo models were adopted to account for physiologically relevant conditions of the gut. Here, we probed beyond conventional phage-bacteria coevolution to investigate potential tripartite evolutionary interactions between phages, their bacterial hosts, and the mammalian gut mucosa. To capture the role of the mammalian gut, we recapitulated a life-like gut mucosal layer using in vitro lab-on-a-chip devices (to wit, the gut-on-a-chip) and showed that the mucosal environment supports stable phage-bacteria coexistence. Next, we experimentally coevolved lytic phage populations within the gut-on-a-chip devices alongside their bacterial hosts. We found that while phages adapt to the mucosal environment via de novo mutations, genetic recombination was the key evolutionary force in driving mutational fitness. A single mutation in the phage capsid protein Hoc-known to facilitate phage adherence to mucus-caused altered phage binding to fucosylated mucin glycans. We demonstrated that the altered glycan-binding phenotype provided the evolved mutant phage a competitive fitness advantage over its ancestral wild-type phage in the gut-on-a-chip mucosal environment. Collectively, our findings revealed that phages-in addition to their evolutionary relationship with bacteria-are able to evolve in response to a mammalian-derived mucosal environment.


Assuntos
Bactérias , Bacteriófagos , Trato Gastrointestinal , Mucosa , Animais , Bactérias/virologia , Bacteriófagos/genética , Bacteriófagos/fisiologia , Proteínas do Capsídeo/genética , Trato Gastrointestinal/virologia , Mucosa/virologia , Muco , Mutação , Simbiose
5.
Mol Biol Evol ; 40(3)2023 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-36788632

RESUMO

Horizontal gene transfer (HGT) is important for microbial evolution, but how evolutionary forces shape the frequencies of horizontally transferred genetic variants in the absence of strong selection remains an open question. In this study, we evolve laboratory populations of Acinetobacter baylyi (ADP1) with HGT from two clinically relevant strains of multidrug-resistant Acinetobacter baumannii (AB5075 and A9844). We find that DNA can cross the species barrier, even without strong selection, and despite substantial DNA sequence divergence between the two species. Our results confirm previous findings that HGT can drive the spread of antibiotic resistance genes (ARGs) without selection for that antibiotic, but not for all of the resistance genes present in the donor genome. We quantify the costs and benefits of horizontally transferred variants and use whole population sequencing to track the spread of ARGs from HGT donors into antibiotic-sensitive recipients. We find that even though most ARGs are taken up by populations of A. baylyi, the long-term fate of an individual gene depends both on its fitness cost and on the type of genetic element that carries the gene. Interestingly, we also found that an integron, but not its host plasmid, is able to spread in A. baylyi populations despite its strong deleterious effect. Altogether, our results show how HGT provides an evolutionary advantage to evolving populations by facilitating the spread of non-selected genetic variation including costly ARGs.


Assuntos
Acinetobacter baumannii , Antibacterianos , Transferência Genética Horizontal , Plasmídeos , Resistência Microbiana a Medicamentos , Acinetobacter baumannii/genética
6.
Am J Transplant ; 2024 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-38499087

RESUMO

Data regarding coronavirus disease 2019 (COVID-19) outcomes in solid organ transplant recipients (SOTr) across severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) waves, including the impact of different measures, are lacking. This cohort study, conducted from March 2020 to May 2023 in Toronto, Canada, aimed to analyze COVID-19 outcomes in 1975 SOTr across various SARS-CoV-2 waves and assess the impact of preventive and treatment measures. The primary outcome was severe COVID-19, defined as requiring supplemental oxygen, with secondary outcomes including hospitalization, length of stay, intensive care unit (ICU) admission, and 30-day and 1-year all-cause mortality. SARS-CoV-2 waves were categorized as Wildtype/Alpha/Delta (318 cases, 16.1%), Omicron BA.1 (268, 26.2%), Omicron BA.2 (268, 13.6%), Omicron BA.5 (561, 28.4%), Omicron BQ.1.1 (188, 9.5%), and Omicron XBB.1.5 (123, 6.2%). Severe COVID-19 rate was highest during the Wildtype/Alpha/Delta wave (44.6%), and lower in Omicron waves (5.7%-16.1%). Lung transplantation was associated with severe COVID-19 (OR: 4.62, 95% CI: 2.71-7.89), along with rituximab treatment (OR: 4.24, 95% CI: 1.04-17.3), long-term corticosteroid use (OR: 3.11, 95% CI: 1.46-6.62), older age (OR: 1.51, 95% CI: 1.30-1.76), chronic lung disease (OR: 2.11, 95% CI: 1.36-3.30), chronic kidney disease (OR: 2.18, 95% CI: 1.17-4.07), and diabetes (OR: 1.97, 95% CI: 1.37-2.83). Early treatment and ≥3 vaccine doses were associated with reduced severity (OR: 0.29, 95% CI: 0.19-0.46, and 0.35, 95% CI: 0.21-0.60, respectively). Tixagevimab/cilgavimab and bivalent boosters did not show a significant impact. The study concludes that COVID-19 severity decreased across different variants in SOTr. Lung transplantation was associated with worse outcomes and may benefit more from preventive and early therapeutic interventions.

7.
Clin Transplant ; 38(1): e15184, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37933602

RESUMO

INTRODUCTION: We evaluated the effect of relative changes in combined tacrolimus and sirolimus (drug) levels, following sirolimus initiation, on outcomes in ambulatory heart transplantation (HTx) recipients. METHODS: We performed a retrospective analysis of HTx recipients who received tacrolimus, followed by sirolimus initiation, any time after HTx. We calculated the relative change in combined drug levels 1-month post-sirolimus initiation, relative to tacrolimus levels pre-initiation, and categorized patients into decreased (≥15% decrease), stable (<15% decrease to <15% increase), or increased (≥15% increase) groups. We compared, across the three groups, changes in post-initiation estimated glomerular filtration rate (eGFR) and left ventricular ejection fraction (LVEF) using one-way ANOVA and Sidák's post-hoc analysis, as well as the individual and composite outcomes of new donor specific antibodies (DSA), acute cellular rejection (ACR), and all-cause mortality using Fisher's exact test. RESULTS: Amongst 99 HTx recipients included, the median age was 53 years, time to sirolimus initiation was 1.5 years post-HTx, and pre-sirolimus eGFR was 52 mL/min/1.73 m2 . Nine patients had decreased, 15 stable, and 75 increased, relative combined drug levels. Relative change in eGFR was significantly higher in patients with decreased levels compared to patients with increased levels at 6 months post-initiation (P < .05), but this was not sustained at 12 months. There were no differences in LVEF change or in individual and composite risks for developing DSA, ACR, and all-cause mortality at 12 months across the groups. CONCLUSION: Post-sirolimus initiation, a relative decrease in combined drug levels, compared to increased levels, was associated with temporarily improved renal function.


Assuntos
Transplante de Coração , Sirolimo , Humanos , Pessoa de Meia-Idade , Sirolimo/uso terapêutico , Imunossupressores/uso terapêutico , Tacrolimo , Estudos Retrospectivos , Volume Sistólico , Função Ventricular Esquerda , Rejeição de Enxerto/tratamento farmacológico , Rejeição de Enxerto/etiologia
8.
Clin Transplant ; 38(5): e15326, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38716786

RESUMO

INTRODUCTION: Induction therapy (IT) utility in heart transplantation (HT) remains contested. Commissioned by a clinical-practice guidelines panel to evaluate the effectiveness and safety of IT in adult HT patients, we conducted this systematic review and network meta-analysis (NMA). METHODS: We searched for studies from January 2000 to October 2022, reporting on the use of any IT agent in adult HT patients. Based on patient-important outcomes, we performed frequentist NMAs separately for RCTs and observational studies with adjusted analyses, and assessed the certainty of evidence using the GRADE framework. RESULTS: From 5156 publications identified, we included 7 RCTs and 12 observational studies, and report on two contemporarily-used IT agents-basiliximab and rATG. The RCTs provide only very low certainty evidence and was uninformative of the effect of the two agents versus no IT or one another. With low certainty in the evidence from observational studies, basiliximab may increase 30-day (OR 1.13; 95% CI 1.06-1.20) and 1-year (OR 1.11; 95% CI 1.02-1.22) mortality compared to no IT. With low certainty from observational studies, rATG may decrease 5-year cardiac allograft vasculopathy (OR .82; 95% CI .74-.90) compared to no IT, as well as 30-day (OR .85; 95% CI .80-.92), 1-year (OR .87; 95% CI .79-.96), and overall (HR .84; 95% CI .76-.93) mortality compared to basiliximab. CONCLUSION: With low and very low certainty in the synthetized evidence, these NMAs suggest possible superiority of rATG compared to basiliximab, but do not provide compelling evidence for the routine use of these agents in HT recipients.


Assuntos
Rejeição de Enxerto , Transplante de Coração , Imunossupressores , Humanos , Rejeição de Enxerto/etiologia , Rejeição de Enxerto/prevenção & controle , Imunossupressores/uso terapêutico , Metanálise em Rede , Prognóstico , Medicina Baseada em Evidências , Sobrevivência de Enxerto/efeitos dos fármacos , Guias de Prática Clínica como Assunto/normas , Quimioterapia de Indução
9.
Clin Transplant ; 38(3): e15270, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38445536

RESUMO

BACKGROUND: The use of induction therapy (IT) agents in the early post-heart transplant period remains controversial. The following recommendations aim to provide guidance on the use of IT agents, including Basiliximab and Thymoglobulin, as part of routine care in heart transplantation (HTx). METHODS: We recruited an international, multidisciplinary panel of 15 stakeholders, including patient partners, transplant cardiologists and surgeons, nurse practitioners, pharmacists, and methodologists. We commissioned a systematic review on benefits and harms of IT on patient-important outcomes, and another on patients' values and preferences to inform our recommendations. We used the GRADE framework to summarize our findings, rate certainty in the evidence, and develop recommendations. The panel considered the balance between benefits and harms, certainty in the evidence, and patient's values and preferences, to make recommendations for or against the routine post-operative use of Thymoglobulin or Basiliximab. RESULTS: The panel made recommendations on three major clinical problems in HTx: (1) We suggest against the routine post-operative use of Basiliximab compared to no IT, (2) we suggest against the routine use of Thymoglobulin compared to no IT, and (3) for those patients for whom IT is deemed desirable, we suggest for the use of Thymoglobulin as compared to Basiliximab. CONCLUSION: This report highlights gaps in current knowledge and provides directions for clinical research in the future to better understand the clinical utility of IT agents in the early post heart transplant period, leading to improved management and care.


Assuntos
Transplante de Coração , Quimioterapia de Indução , Humanos , Metanálise em Rede , Basiliximab , Transplante de Coração/efeitos adversos , Coração
10.
Reprod Domest Anim ; 59(1): e14498, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37902253

RESUMO

Anti-Müllerian hormone (AMH) is secreted by granulosa cells of healthy, growing follicles and is positively correlated with the ovarian reserve. Maternal and environmental factors, such as nutrition, disease, parity and endocrine disruptors, are thought to have a profound impact on ovarian reserve development during early foetal life. For genetic progress, it can be advantageous to breed dairy replacements from heifers to expedite the generation interval; however, there is some evidence that nulliparous animals produce female offspring with smaller ovarian reserves compared with multiparous animals. The objective of this prospective, observational study was to determine whether maternal growth in the pre-conception and early gestational period of nulliparous dairy heifers is associated with pre-weaning AMH concentrations in their female offspring. Our hypothesis was that excessive growth in this period would negatively impact AMH concentrations. Seasonal, pasture-based dairy heifer calves (n = 156) born from nulliparous dams, from six Irish farms, were blood sampled at an average of 60 days of age in spring 2022 and tested for AMH. Mixed-effects linear regression models were constructed with Box-Cox transformed AMH concentration as the dependent variable. The independent variables tested included maternal average daily gain (ADG) from pre-breeding examination (PBE) to pregnancy diagnosis (PD) between 30 and 60 days in calf (DIC), ADG from PBE to PD over 60 DIC and ADG between the two PDs. Calf breed and age at sampling were forced into the models, and the farm was treated as a random effect in all models. We found that as ADG increased from the pre-breeding period to their first PD visit, the AMH concentration in their offspring reduced. However, ADG explained only a small amount of the variation in AMH concentrations (marginal R2 = 0.041). In conclusion, the results of our study suggest that excessive growth prior to conception and in early gestation of nulliparous heifers could impact the ovarian reserve of their female offspring, and may imply that farmers should avoid excessive growth in the immediate pre-breeding and early gestational periods.


Assuntos
Hormônio Antimülleriano , Hormônios Peptídicos , Gravidez , Bovinos , Animais , Feminino , Estudos Prospectivos , Fertilização , Paridade , Parto
11.
Emerg Infect Dis ; 29(6): 1223-1227, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37141617

RESUMO

Anthropogenic transmission of SARS-CoV-2 to pet cats highlights the importance of monitoring felids for exposure to circulating variants. We tested cats in the United Kingdom for SARS-CoV-2 antibodies; seroprevalence peaked during September 2021-February 2022. The variant-specific response in cats trailed circulating variants in humans, indicating multiple human-to-cat transmissions over a prolonged period.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Gatos , Animais , Estudos Soroepidemiológicos , COVID-19/epidemiologia , COVID-19/veterinária , Anticorpos Antivirais , Reino Unido/epidemiologia
12.
Biol Reprod ; 109(5): 749-758, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37658765

RESUMO

Harnessing information from the maternal blood to predict fetal growth is attractive yet scarcely explored in livestock. The objectives were to determine the transcriptomic modifications in maternal blood and fetal liver, gonads, and heart according to fetal weight and to model a molecular signature based on the fetal organs allowing the prediction of fetal weight from the maternal blood transcriptome in cattle. In addition to a contemporaneous maternal blood sample, organ samples were collected from 10 male fetuses at 42 days of gestation for RNA-sequencing. Fetal weight ranged from 1.25 to 1.69 g (mean = 1.44 ± 0.15 g). Clustering data analysis revealed clusters of co-expressed genes positively correlated with fetal weight and enriching ontological terms biologically relevant for the organ. For the heart, the 1346 co-expressed genes were involved in energy generation and protein synthesis. For the gonads, the 1042 co-expressed genes enriched seminiferous tubule development. The 459 co-expressed genes identified in the liver were associated with lipid synthesis and metabolism. Finally, the cluster of 571 co-expressed genes determined in maternal blood enriched oxidative phosphorylation and thermogenesis. Next, data from the fetal organs were used to train a regression model of fetal weight, which was predicted with the maternal blood data. The best prediction was achieved when the model was trained with 35 co-expressed genes overlapping between heart and maternal blood (root-mean-square error = 0.04, R2 = 0.93). In conclusion, linking transcriptomic information from maternal blood with that from the fetal heart unveiled maternal blood as a predictor of fetal development.


Assuntos
Peso Fetal , Transcriptoma , Masculino , Bovinos , Animais , Desenvolvimento Fetal/genética , Organogênese , Perfilação da Expressão Gênica/veterinária
13.
Heart Fail Rev ; 28(1): 35-45, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-35325323

RESUMO

In heart failure (HF) patients, the pathophysiological mechanisms of severe exercise intolerance and impaired exercise capacity are related to both central and peripheral abnormalities. The central abnormalities in HF patients include impaired cardiac function and chronotropic incompetence (CI). Indeed, CI, the inability to adequately increase heart rate (HR) from rest to exercise often exhibited by HF patients, is related to activation of the sympathetic nervous system (SNS) yielding a rise in circulating norepinephrine (NE). CI may result from downregulation of ß-adrenergic receptors, ß-blocker usage, high baseline HR, or due to a combination of factors. This paper discusses the role of elevated NE in altering chronotropic responses in HF patients and consequently resulting in impaired exercise capacity. We suggest that future research should focus on the potential treatment of CI with rate-adaptive pacing, using a sensor to measure physical activity, without inducing deleterious hormonal activation of the sympathetic system.


Assuntos
Insuficiência Cardíaca , Norepinefrina , Humanos , Tolerância ao Exercício , Antagonistas Adrenérgicos beta , Exercício Físico/fisiologia , Frequência Cardíaca/fisiologia , Teste de Esforço
14.
Nature ; 551(7678): 45-50, 2017 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-29045390

RESUMO

The outcomes of evolution are determined by a stochastic dynamical process that governs how mutations arise and spread through a population. However, it is difficult to observe these dynamics directly over long periods and across entire genomes. Here we analyse the dynamics of molecular evolution in twelve experimental populations of Escherichia coli, using whole-genome metagenomic sequencing at five hundred-generation intervals through sixty thousand generations. Although the rate of fitness gain declines over time, molecular evolution is characterized by signatures of rapid adaptation throughout the duration of the experiment, with multiple beneficial variants simultaneously competing for dominance in each population. Interactions between ecological and evolutionary processes play an important role, as long-term quasi-stable coexistence arises spontaneously in most populations, and evolution continues within each clade. We also present evidence that the targets of natural selection change over time, as epistasis and historical contingency alter the strength of selection on different genes. Together, these results show that long-term adaptation to a constant environment can be a more complex and dynamic process than is often assumed.


Assuntos
Escherichia coli/crescimento & desenvolvimento , Escherichia coli/genética , Evolução Molecular , Análise Mutacional de DNA , Epistasia Genética , Fósseis , Frequência do Gene , Aptidão Genética , Genoma Bacteriano/genética , Metagenômica , Taxa de Mutação , Seleção Genética
15.
Proc Natl Acad Sci U S A ; 117(43): 26868-26875, 2020 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-33055207

RESUMO

Horizontal gene transfer (HGT) confers the rapid acquisition of novel traits and is pervasive throughout microbial evolution. Despite the central role of HGT, the evolutionary forces that drive the dynamics of HGT alleles in evolving populations are poorly understood. Here, we show that HGT alters the evolutionary dynamics of genetic variation, so that deleterious genetic variants, including antibiotic resistance genes, can establish in populations without selection. We evolve antibiotic-sensitive populations of the human pathogen Helicobacter pylori in an environment without antibiotic but with HGT from an antibiotic-resistant isolate of H. pylori We find that HGT increases the rate of adaptation, with most horizontally transferred genetic variants establishing at a low frequency in the population. When challenged with antibiotic, this low-level variation potentiates adaptation, with HGT populations flourishing in conditions where nonpotentiated populations go extinct. By extending previous models of evolution under HGT, we evaluated the conditions for the establishment and spread of HGT-acquired alleles into recipient populations. We then used our model to estimate parameters of HGT and selection from our experimental evolution data. Together, our findings show how HGT can act as an evolutionary force that facilitates the spread of nonselected genetic variation and expands the adaptive potential of microbial populations.


Assuntos
Adaptação Fisiológica/genética , Evolução Biológica , Farmacorresistência Bacteriana/genética , Transferência Genética Horizontal , Helicobacter pylori/genética , Antibacterianos , Fluxo Gênico , Aptidão Genética , Variação Genética , Metronidazol , Seleção Genética
16.
Proc Natl Acad Sci U S A ; 117(50): 31954-31962, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33229566

RESUMO

Canine distemper virus (CDV) has recently emerged as an extinction threat for the endangered Amur tiger (Panthera tigris altaica). CDV is vaccine-preventable, and control strategies could require vaccination of domestic dogs and/or wildlife populations. However, vaccination of endangered wildlife remains controversial, which has led to a focus on interventions in domestic dogs, often assumed to be the source of infection. Effective decision making requires an understanding of the true reservoir dynamics, which poses substantial challenges in remote areas with diverse host communities. We carried out serological, demographic, and phylogenetic studies of dog and wildlife populations in the Russian Far East to show that a number of wildlife species are more important than dogs, both in maintaining CDV and as sources of infection for tigers. Critically, therefore, because CDV circulates among multiple wildlife sources, dog vaccination alone would not be effective at protecting tigers. We show, however, that low-coverage vaccination of tigers themselves is feasible and would produce substantive reductions in extinction risks. Vaccination of endangered wildlife provides a valuable component of conservation strategies for endangered species.


Assuntos
Cinomose/prevenção & controle , Espécies em Perigo de Extinção/economia , Tigres/virologia , Vacinação/economia , Vacinas Virais/administração & dosagem , Animais , Animais Selvagens/virologia , Tomada de Decisões Gerenciais , Reservatórios de Doenças/veterinária , Reservatórios de Doenças/virologia , Cinomose/epidemiologia , Cinomose/transmissão , Cinomose/virologia , Vírus da Cinomose Canina/genética , Vírus da Cinomose Canina/imunologia , Cães/sangue , Cães/virologia , Estudos de Viabilidade , Feminino , Masculino , Modelos Econômicos , Filogenia , Estudos Soroepidemiológicos , Sibéria , Tigres/sangue , Vacinação/métodos , Cobertura Vacinal/economia , Cobertura Vacinal/métodos , Cobertura Vacinal/organização & administração , Vacinas Virais/economia
17.
J Environ Manage ; 348: 119307, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37862886

RESUMO

Flue gas desulfurization (FGD) gypsum, a by-product of carbon-based energy sources, has typically been incorporated as a component of concrete mixes and wallboard and beneficially used as an agricultural amendment to enhance terrestrial crop production and improve the quality of runoff. These various uses for the by-product aid in reducing the amount that is ultimately landfilled. Limited studies have investigated its benefits when used directly in aquatic settings, such as ponds and lakes, to increase hardness and potentially mitigate eutrophication. A 36-day field mesocosm experiment tested a larger range of FGD gypsum concentrations (500-2000 mg/L) than those previously tested in the literature to investigate its desired and potentially undesired impacts on water quality, including the algal community. High FGD gypsum concentrations, 1000 and 2000 mg/L, were found to have more undesired impacts than the 500 mg/L treatment, including an initial spike in cyanobacteria, a decrease in total zooplankton abundance, and an increase in certain trace metals in the highest treatment. Ultimately, the 500 mg/L FGD gypsum treatment was found to have fewer undesired impacts while still resulting in significant desired effects, including those on hardness and pH, as well as moderate reductions in algal abundance. This experiment provides a better understanding of the effects of FGD gypsum when directly used in an aquatic setting, determines an optimal dose for future field experiments, and helps provide the groundwork for developing an upper threshold on FGD gypsum so as to not have the negative effects outweigh the positive.


Assuntos
Oligoelementos , Qualidade da Água , Sulfato de Cálcio , Agricultura , Plantas
18.
Nature ; 531(7593): 233-6, 2016 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-26909573

RESUMO

Sex and recombination are pervasive throughout nature despite their substantial costs. Understanding the evolutionary forces that maintain these phenomena is a central challenge in biology. One longstanding hypothesis argues that sex is beneficial because recombination speeds adaptation. Theory has proposed several distinct population genetic mechanisms that could underlie this advantage. For example, sex can promote the fixation of beneficial mutations either by alleviating interference competition (the Fisher-Muller effect) or by separating them from deleterious load (the ruby in the rubbish effect). Previous experiments confirm that sex can increase the rate of adaptation, but these studies did not observe the evolutionary dynamics that drive this effect at the genomic level. Here we present the first, to our knowledge, comparison between the sequence-level dynamics of adaptation in experimental sexual and asexual Saccharomyces cerevisiae populations, which allows us to identify the specific mechanisms by which sex speeds adaptation. We find that sex alters the molecular signatures of evolution by changing the spectrum of mutations that fix, and confirm theoretical predictions that it does so by alleviating clonal interference. We also show that substantially deleterious mutations hitchhike to fixation in adapting asexual populations. In contrast, recombination prevents such mutations from fixing. Our results demonstrate that sex both speeds adaptation and alters its molecular signature by allowing natural selection to more efficiently sort beneficial from deleterious mutations.


Assuntos
Adaptação Fisiológica/genética , Evolução Molecular , Mutação/genética , Reprodução Assexuada/fisiologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/fisiologia , Seleção Genética/genética , Sexo , Células Clonais/citologia , Células Clonais/metabolismo , Aptidão Genética/genética , Genética Populacional , Modelos Genéticos , Recombinação Genética/genética , Reprodução Assexuada/genética , Saccharomyces cerevisiae/citologia , Fatores de Tempo
19.
Nature ; 534(7606): 218-21, 2016 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-27279215

RESUMO

Supermassive black holes in galaxy centres can grow by the accretion of gas, liberating energy that might regulate star formation on galaxy-wide scales. The nature of the gaseous fuel reservoirs that power black hole growth is nevertheless largely unconstrained by observations, and is instead routinely simplified as a smooth, spherical inflow of very hot gas. Recent theory and simulations instead predict that accretion can be dominated by a stochastic, clumpy distribution of very cold molecular clouds--a departure from the 'hot mode' accretion model--although unambiguous observational support for this prediction remains elusive. Here we report observations that reveal a cold, clumpy accretion flow towards a supermassive black hole fuel reservoir in the nucleus of the Abell 2597 Brightest Cluster Galaxy (BCG), a nearby (redshift z = 0.0821) giant elliptical galaxy surrounded by a dense halo of hot plasma. Under the right conditions, thermal instabilities produce a rain of cold clouds that fall towards the galaxy's centre, sustaining star formation amid a kiloparsec-scale molecular nebula that is found at its core. The observations show that these cold clouds also fuel black hole accretion, revealing 'shadows' cast by the molecular clouds as they move inward at about 300 kilometres per second towards the active supermassive black hole, which serves as a bright backlight. Corroborating evidence from prior observations of warmer atomic gas at extremely high spatial resolution, along with simple arguments based on geometry and probability, indicate that these clouds are within the innermost hundred parsecs of the black hole, and falling closer towards it.

20.
Neurobiol Dis ; 156: 105399, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34029695

RESUMO

Immune system hypersensitivity is believed to contribute to mental frailty in the elderly. Solid evidence indicates NOD-like receptor pyrin domain containing-3 (NLRP3)-inflammasome activation intimately connects aging-associated chronic inflammation (inflammaging) to senile cognitive decline. Thioredoxin interacting protein (TXNIP), an inducible protein involved in oxidative stress, is essential for NLRP3 inflammasome activity. This study aims to find whether TXNIP/NLRP3 inflammasome pathway is involved in senile dementia. According to our studies on sex-matched mice, TXNIP was significantly upregulated in aged animals, paralleled by the NLRP3-inflammasome over-activity leading to enhanced caspase-1 cleavage and IL-1ß maturation, in both sexes. This was closely associated with depletion of the anti-aging and cognition enhancing protein klotho, in aged males. Txnip knockout reversed age-related NLRP3-hyperactivity and enhanced thioredoxin (TRX) levels. Further, TXNIP inhibition along with verapamil replicated TXNIP/NLRP3-inflammasome downregulation in aged animals, with FOXO-1 and mTOR upregulation. These alterations concurred with substantial improvements in both cognitive and sensorimotor abilities. Together, these findings substantiate the pivotal role of TXNIP to drive inflammaging in parallel with klotho depletion and functional decline, and delineate thioredoxin system as a potential target to decelerate senile dementia.


Assuntos
Envelhecimento/metabolismo , Encéfalo/metabolismo , Proteínas de Transporte/biossíntese , Mediadores da Inflamação/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/biossíntese , Tiorredoxinas/biossíntese , Envelhecimento/genética , Envelhecimento/patologia , Animais , Encéfalo/patologia , Proteínas de Transporte/antagonistas & inibidores , Proteínas de Transporte/genética , Feminino , Mediadores da Inflamação/antagonistas & inibidores , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína 3 que Contém Domínio de Pirina da Família NLR/antagonistas & inibidores , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Estresse Oxidativo/fisiologia , Tiorredoxinas/antagonistas & inibidores , Tiorredoxinas/genética
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