Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 51
Filtrar
1.
Ecol Evol ; 14(4): e11275, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38654712

RESUMEN

In July 2016, East Bank of Flower Garden Banks (FGB) National Marine Sanctuary experienced a localized mortality event (LME) of multiple invertebrate species that ultimately led to reductions in coral cover. Abiotic data taken directly after the event suggested that acute deoxygenation contributed to the mortality. Despite the large impact of this event on the coral community, there was no direct evidence that this LME was driven by acute deoxygenation, and thus we explored whether gene expression responses of corals to the LME would indicate what abiotic factors may have contributed to the LME. Gene expression of affected and unaffected corals sampled during the mortality event revealed evidence of the physiological consequences of the LME on coral hosts and their algal symbionts from two congeneric species (Orbicella franksi and Orbicella faveolata). Affected colonies of both species differentially regulated genes involved in mitochondrial regulation and oxidative stress. To further test the hypothesis that deoxygenation led to the LME, we measured coral host and algal symbiont gene expression in response to ex situ experimental deoxygenation (control = 6.9 ± 0.08 mg L-1, anoxic = 0.083 ± 0.017 mg L-1) in healthy O. faveolata colonies from the FGB. However, this deoxygenation experiment revealed divergent gene expression patterns compared to the corals sampled during the LME and was more similar to a generalized coral environmental stress response. It is therefore likely that while the LME was connected to low oxygen, it was a series of interconnected stressors that elicited the unique gene expression responses observed here. These in situ and ex situ data highlight how field responses to stressors are unique from those in controlled laboratory conditions, and that the complexities of deoxygenation events in the field likely arise from interactions between multiple environmental factors simultaneously.

2.
Mol Ecol ; 33(8): e17318, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38488669

RESUMEN

Increasing ocean temperatures are causing dysbiosis between coral hosts and their symbionts. Previous work suggests that coral host gene expression responds more strongly to environmental stress compared to their intracellular symbionts; however, the causes and consequences of this phenomenon remain untested. We hypothesized that symbionts are less responsive because hosts modulate symbiont environments to buffer stress. To test this hypothesis, we leveraged the facultative symbiosis between the scleractinian coral Oculina arbuscula and its symbiont Breviolum psygmophilum to characterize gene expression responses of both symbiotic partners in and ex hospite under thermal challenges. To characterize host and in hospite symbiont responses, symbiotic and aposymbiotic O. arbuscula were exposed to three treatments: (1) control (18°C), (2) heat (32°C), and (3) cold (6°C). This experiment was replicated with B. psygmophilum cultured from O. arbuscula to characterize ex hospite symbiont responses. Both thermal challenges elicited classic environmental stress responses (ESRs) in O. arbuscula regardless of symbiotic state, with hosts responding more strongly to cold challenge. Hosts also exhibited stronger responses than in hospite symbionts. In and ex hospite B. psygmophilum both down-regulated gene ontology pathways associated with photosynthesis under thermal challenge; however, ex hospite symbionts exhibited greater gene expression plasticity and differential expression of genes associated with ESRs. Taken together, these findings suggest that O. arbuscula hosts may buffer environments of B. psygmophilum symbionts; however, we outline the future work needed to confirm this hypothesis.


Asunto(s)
Antozoos , Dinoflagelados , Animales , Antozoos/genética , Simbiosis/genética , Estrés Fisiológico/genética , Calor , Expresión Génica , Arrecifes de Coral , Dinoflagelados/genética
3.
Nat Commun ; 14(1): 4342, 2023 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-37468468

RESUMEN

Although the role of the Wnt pathway in colon carcinogenesis has been described previously, it has been recently demonstrated that Wnt signaling originates from highly dynamic nano-assemblies at the plasma membrane. However, little is known regarding the role of oncogenic APC in reshaping Wnt nanodomains. This is noteworthy, because oncogenic APC does not act autonomously and requires activation of Wnt effectors upstream of APC to drive aberrant Wnt signaling. Here, we demonstrate the role of oncogenic APC in increasing plasma membrane free cholesterol and rigidity, thereby modulating Wnt signaling hubs. This results in an overactivation of Wnt signaling in the colon. Finally, using the Drosophila sterol auxotroph model, we demonstrate the unique ability of exogenous free cholesterol to disrupt plasma membrane homeostasis and drive Wnt signaling in a wildtype APC background. Collectively, these findings provide a link between oncogenic APC, loss of plasma membrane homeostasis and CRC development.


Asunto(s)
Vía de Señalización Wnt , beta Catenina , Animales , beta Catenina/genética , beta Catenina/metabolismo , Carcinogénesis/genética , Membrana Celular/metabolismo , Colon/metabolismo , Drosophila/metabolismo , Vía de Señalización Wnt/genética
5.
Leuk Lymphoma ; 63(14): 3331-3339, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36120910

RESUMEN

There are limited data describing the impact of active surveillance on longitudinal health-related quality of life (HRQoL) in patients with indolent non-Hodgkin lymphomas (NHL). A cohort of untreated indolent NHL patients completed FACT-LYM questionnaires at 6, 12, 18, 24, and 36 months after diagnosis. Longitudinal FACT-LYM scores were analyzed by ANOVA and generalized linear mixed models. Indolent NHL scores were compared to norm general population scores. A total of 52 patients were identified, of which 46 (88%) remained on active surveillance at 36 months. There was no significant change in any of the FACT-LYM scores over 36 months. As compared to the general population, indolent NHL patients had higher, clinically meaningful scores in physical, functional, and social well-being, but not emotional well-being. Patients with indolent NHL on active surveillance have globally preserved HRQoL for up to 3 years after diagnosis. Emotional well-being continues to be an unmet need during active surveillance.


Asunto(s)
Linfoma no Hodgkin , Calidad de Vida , Humanos , Calidad de Vida/psicología , Espera Vigilante , Linfoma no Hodgkin/patología , Encuestas y Cuestionarios
6.
Tob Prev Cessat ; 8: 24, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35811784

RESUMEN

INTRODUCTION: While promising evidence from trials of social-media-based stop smoking support informs service-planning, there is a need for more prospective, observational studies of smoking cessation interventions to build 'real-world' evidence. Specifically, user experiences have been under-explored with qualitative methods to date. This mixed-method evaluation of a closed Facebook group-based behavioral stop smoking support program, which was conducted in Ireland in 2018, aimed to address these issues. METHODS: Pre- and post-program surveys measured smoking abstinence (self-reported 7-day point prevalence), changes in smoking attitudes and behavior, and participant experiences. Engagement with Facebook was measured through counting 'likes' and comments, and was used to categorize groups as 'more active' and 'less active' over a 12-week period of support. Thematic content analysis of semi-structured participant interviews explored program experience in depth. RESULTS: In total, 13 of 52 participants reported smoking abstinence post-program (25.0%, 95% CI: 14.0-39.0). Participant engagement with Facebook was variable and decreased over the program. Membership of a 'more active' group was associated with better reported participant experience (e.g. 90.9% agreeing 'Facebook group helped me to quit or reduce smoking', versus 33.3% in the 'less active' group, p<0.05). Qualitative analysis identified three over-arching themes: importance of social interactions; perception of health information; and appeal of online support. CONCLUSIONS: Facebook can be used to deliver group-based behavioral stop smoking support in the real world. In Ireland, the one-month post-program abstinence outcomes achieved by other stop smoking services is approximately 50%, and while the outcomes for this service was lower (25%), it is still better than outcomes estimated for unassisted quitting. Engagement and peer-to-peer interactivity should be maximized to support positive participant experience.

7.
BMJ Case Rep ; 15(7)2022 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-35882436

RESUMEN

Fragile X (FXS) and Turner (TS) syndromes are X-chromosome-associated disorders. Herein, we report the case of a girl in middle childhood with bicuspid aortic valve in infancy, growth failure, global developmental delay (GDD), visual problems, and coexisting attention-deficit/hyperactivity and anxiety disorders. A high-resolution karyotype in 20 cells revealed 46,X,Idic(X)(p11.21)[19]/45,X[1], suggestive of variant TS. Given her atypical phenotype, subsequent DNA testing was performed. Four FMR1 cytosine-guanine-guanine repeats (30, 410, 580 and 800) were identified, confirming the additional FXS diagnosis. This case study highlights the importance of additional genetic testing in individuals with atypical variant TS, such as unexplained GDD and distinct facial characteristics. The additional FXS diagnosis prompted new therapeutic development for the patient to advance precision healthcare.


Asunto(s)
Trastornos de los Cromosomas , Síndrome del Cromosoma X Frágil , Síndrome de Turner , Niño , Aberraciones Cromosómicas , Femenino , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/genética , Síndrome del Cromosoma X Frágil/complicaciones , Síndrome del Cromosoma X Frágil/diagnóstico , Síndrome del Cromosoma X Frágil/genética , Guanina , Humanos , Síndrome de Turner/complicaciones , Síndrome de Turner/diagnóstico , Síndrome de Turner/genética , Cromosoma X
8.
Physiol Rep ; 10(13): e15363, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35778808

RESUMEN

In humans and animal models, Cesarean section (C-section) has been associated with alterations in the taxonomic structure of the gut microbiome. These changes in microbiota populations are hypothesized to impact immune, metabolic, and behavioral/neurologic systems and others. It is not clear if birth mode inherently changes the microbiome, or if C-section effects are context-specific and involve interactions with environmental and other factors. To address this and control for potential confounders, cecal microbiota from ~3 week old mice born by C-section (n = 16) versus natural birth (n = 23) were compared under matched conditions for housing, cross-fostering, diet, sex, and genetic strain. A total of 601 unique species were detected across all samples. Alpha diversity richness (i.e., how many species within sample; Chao1) and evenness/dominance (i.e., Shannon, Simpson, Inverse Simpson) metrics revealed no significant differences by birth mode. Beta diversity (i.e., differences between samples), as estimated with Bray-Curtis dissimilarities and Aitchison distances (using log[x + 1]-transformed counts), was also not significantly different (Permutational Multivariate ANOVA [PERMANOVA]). Only the abundance of Lachnoclostridium [Clostridium] scindens was found to differ using a combination of statistical methods (ALDEx2, DESeq2), being significantly higher in C-section mice. This microbe has been implicated in secondary bile acid production and regulation of glucocorticoid metabolism to androgens. From our results and the extant literature we conclude that C-section does not inherently lead to large-scale shifts in gut microbiota populations, but birth mode could modulate select bacteria in a context-specific manner: For example, involving factors associated with pre-, peri-, and postpartum environments, diet or host genetics.


Asunto(s)
Ácidos y Sales Biliares , Cesárea , Animales , Ciego , Clostridium , Femenino , Glucocorticoides , Ratones , Embarazo
9.
PeerJ ; 10: e13158, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35368334

RESUMEN

Microfragmentation is the act of cutting corals into small pieces (~1 cm2) to accelerate the growth rates of corals relative to growth rates observed when maintaining larger-sized fragments. This rapid tissue and skeletal expansion technique offers great potential for supporting reef restoration, yet the biological processes and tradeoffs involved in microfragmentation-mediated accelerated growth are not well understood. Here we compared growth rates across a range of successively smaller fragment sizes in multiple genets of reef-building corals, Orbicella faveolata and Montastraea cavernosa. Our results confirm prior findings that smaller initial sizes confer accelerated growth after four months of recovery in a raceway. O. faveolata transcript levels associated with growth rate include genes encoding carbonic anhydrase and glutamic acid-rich proteins, which have been previously implicated in coral biomineralization, as well as a number of unannotated transcripts that warrant further characterization. Innate immunity enzyme activity assays and gene expression results suggest a potential tradeoff between growth rate after microfragmentation and immune investment. Microfragmentation-based restoration practices have had great success on Caribbean reefs, despite widespread mortality among wild corals due to infectious diseases. Future studies should continue to examine potential immune tradeoffs throughout the microfragmentation recovery period that may affect growout survival and disease transmission after outplanting.


Asunto(s)
Antozoos , Animales , Antozoos/genética , Región del Caribe
11.
PLoS Biol ; 19(6): e3001282, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-34129646

RESUMEN

Success and impact metrics in science are based on a system that perpetuates sexist and racist "rewards" by prioritizing citations and impact factors. These metrics are flawed and biased against already marginalized groups and fail to accurately capture the breadth of individuals' meaningful scientific impacts. We advocate shifting this outdated value system to advance science through principles of justice, equity, diversity, and inclusion. We outline pathways for a paradigm shift in scientific values based on multidimensional mentorship and promoting mentee well-being. These actions will require collective efforts supported by academic leaders and administrators to drive essential systemic change.


Asunto(s)
Recompensa , Ciencia , Sesgo , Diversidad Cultural , Humanos , Tutoría
12.
R Soc Open Sci ; 8(4): 210113, 2021 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-33996131

RESUMEN

Rampant coral disease, exacerbated by climate change and other anthropogenic stressors, threatens reefs worldwide, especially in the Caribbean. Physically isolated yet genetically connected reefs such as Flower Garden Banks National Marine Sanctuary (FGBNMS) may serve as potential refugia for degraded Caribbean reefs. However, little is known about the mechanisms and trade-offs of pathogen resistance in reef-building corals. Here, we measure pathogen resistance in Montastraea cavernosa from FGBNMS. We identified individual colonies that demonstrated resistance or susceptibility to Vibrio spp. in a controlled laboratory environment. Long-term growth patterns suggest no trade-off between disease resistance and calcification. Predictive (pre-exposure) gene expression highlights subtle differences between resistant and susceptible genets, encouraging future coral disease studies to investigate associations between resistance and replicative age and immune cell populations. Predictive gene expression associated with long-term growth underscores the role of transmembrane proteins involved in cell adhesion and cell-cell interactions, contributing to the growing body of knowledge surrounding genes that influence calcification in reef-building corals. Together these results demonstrate that coral genets from isolated sanctuaries such as FGBNMS can withstand pathogen challenges and potentially aid restoration efforts in degraded reefs. Furthermore, gene expression signatures associated with resistance and long-term growth help inform strategic assessment of coral health parameters.

13.
Clin Pharmacol Ther ; 109(3): 688-696, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33210302

RESUMEN

Interleukin-6 (IL-6)-mediated hyperinflammation may contribute to the mortality of coronavirus disease 2019 (COVID-19). The IL-6 receptor-blocking monoclonal antibody tocilizumab has been repurposed for COVID-19, but prospective trials and dose-finding studies in COVID-19 have not yet fully reported. We conducted a single-arm phase II trial of low-dose tocilizumab in nonintubated hospitalized adult patients with COVID-19, radiographic pulmonary infiltrate, fever, and C-reactive protein (CRP) ≥ 40 mg/L. We hypothesized that doses significantly lower than the emerging standards of 400 mg or 8 mg/kg would resolve clinical and laboratory indicators of hyperinflammation. A dose range from 40 to 200 mg was evaluated, with allowance for one repeat dose at 24 to 48 hours. The primary objective was to assess the relationship of dose to fever resolution and CRP response. Thirty-two patients received low-dose tocilizumab, with the majority experiencing fever resolution (75%) and CRP decline consistent with IL-6 pathway abrogation (86%) in the 24-48 hours following drug administration. There was no evidence of a relationship between dose and fever resolution or CRP decline over the dose range of 40-200 mg. Within the 28-day follow-up, 5 (16%) patients died. For patients who recovered, median time to clinical recovery was 3 days (interquartile range, 2-5). Clinically presumed and/or cultured bacterial superinfections were reported in 5 (16%) patients. Low-dose tocilizumab was associated with rapid improvement in clinical and laboratory measures of hyperinflammation in hospitalized patients with COVID-19. Results of this trial provide rationale for a randomized, controlled trial of low-dose tocilizumab in COVID-19.


Asunto(s)
Anticuerpos Monoclonales Humanizados , Proteína C-Reactiva/análisis , Tratamiento Farmacológico de COVID-19 , COVID-19 , Fiebre , Neumonía Viral , Anciano , Antiinflamatorios/administración & dosificación , Antiinflamatorios/efectos adversos , Antiinflamatorios/farmacología , Anticuerpos Monoclonales Humanizados/administración & dosificación , Anticuerpos Monoclonales Humanizados/efectos adversos , Anticuerpos Monoclonales Humanizados/farmacocinética , COVID-19/sangre , COVID-19/fisiopatología , Relación Dosis-Respuesta a Droga , Monitoreo de Drogas/métodos , Femenino , Fiebre/diagnóstico , Fiebre/tratamiento farmacológico , Humanos , Masculino , Neumonía Viral/diagnóstico , Neumonía Viral/tratamiento farmacológico , Neumonía Viral/etiología , Receptores de Interleucina-6/antagonistas & inhibidores , SARS-CoV-2/aislamiento & purificación , Índice de Severidad de la Enfermedad , Factores de Tiempo , Resultado del Tratamiento
14.
EMBO J ; 39(19): e104319, 2020 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-32915464

RESUMEN

The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that senses xenobiotics, diet, and gut microbial-derived metabolites, is increasingly recognized as a key regulator of intestinal biology. However, its effects on the function of colonic stem and progenitor cells remain largely unexplored. Here, we observed that inducible deletion of AhR in Lgr5+ stem cells increases the percentage of colonic stem cells and enhances organoid initiating capacity and growth of sorted stem and progenitor cells, while AhR activation has the opposite effect. Moreover, intestinal-specific AhR knockout increases basal stem cell and crypt injury-induced cell proliferation and promotes colon tumorigenesis in a preclinical colitis-associated tumor model by upregulating FoxM1 signaling. Mechanistically, AhR transcriptionally suppresses FoxM1 expression. Activation of AhR in human organoids recapitulates phenotypes observed in mice, such as reduction in the percentage of colonic stem cells, promotion of stem cell differentiation, and attenuation of FoxM1 signaling. These findings indicate that the AhR-FoxM1 axis, at least in part, mediates colonic stem/progenitor cell behavior.


Asunto(s)
Colon/metabolismo , Proteína Forkhead Box M1/metabolismo , Receptores de Hidrocarburo de Aril/deficiencia , Transducción de Señal , Células Madre/metabolismo , Animales , Femenino , Proteína Forkhead Box M1/genética , Técnicas de Inactivación de Genes , Humanos , Masculino , Ratones , Ratones Transgénicos , Receptores de Hidrocarburo de Aril/metabolismo
15.
medRxiv ; 2020 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-32743594

RESUMEN

Background Interleukin-6 (IL-6)-mediated hyperinflammation may contribute to the high mortality of coronavirus disease 2019 (Covid-19). Tocilizumab, an IL-6 receptor blocking monoclonal antibody, has been repurposed for Covid-19, but prospective trials and dose-finding studies in Covid-19 are lacking. Methods We conducted a phase 2 trial of low-dose tocilizumab in hospitalized adult patients with Covid-19, radiographic pulmonary infiltrate, fever, and C-reactive protein (CRP) >= 40 mg/L who did not require mechanical ventilation. Dose cohorts were determined by a trial Operations Committee, stratified by CRP and epidemiologic risk factors. A range of doses from 40 to 200 mg (low-dose tocilizumab) was evaluated, with allowance for one repeat dose at 24-48 hours. The primary objective was to assess the relationship of dose to fever resolution and CRP response. Outcomes were compared with retrospective controls with Covid-19. Correlative studies evaluating host antibody response were performed in parallel. Findings A total of 32 patients received low-dose tocilizumab. This cohort had improved fever resolution (75.0% vs. 34.2%, p = 0.001) and CRP decline (86.2% vs. 14.3%, p < 0.001) in the 24-48 hours following drug administration, as compared to the retrospective controls (N=41). The probabilities of fever resolution or CRP decline did not appear to be dose-related in this small study (p=0.80 and p=0.10, respectively). Within the 28-day follow-up, 5 (15.6%) patients died. For patients who recovered, median time to clinical recovery was 3 days (IQR, 2-5). Clinically presumed and/or cultured bacterial superinfections were reported in 5 (15.6%) patients. Correlative biological studies demonstrated that tocilizumab-treated patients produced anti-SARS-CoV-2 antibodies comparable to controls. Interpretation Low-dose tocilizumab was associated with rapid improvement in clinical and laboratory measures of hyperinflammation in hospitalized patients with Covid-19. Results of this trial and its correlative biological studies provide rationale for a randomized, controlled trial of low-dose tocilizumab in Covid-19.

16.
Biol Blood Marrow Transplant ; 26(8): 1527-1533, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32422252

RESUMEN

This study of patients with acute myelogenous leukemia (AML) age ≥60 years analyzed the association between patients' performance indices-Hematopoietic Stem Cell Transplantation Comorbidity Index (HCT-CI), Karnofsky Performance Score (KPS), and European Society for Blood and Marrow Transplantation (EBMT) risk score-before undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) and quality of life (QoL), quantified using the Functional Assessment of Cancer Therapy-Bone Marrow Transplant Scale (FACT-BMT), in the first year after allo-HSCT. Over a period of 7 years, 48 evaluable patients underwent reduced-intensity conditioning allo-HSCT. The median patient age was 65 years (range, 60 to 74 years), with 2-year and 5-year overall survival (OS) of 65.8% and 52.3%, respectively. A significant improvement across all QoL scores was observed over the 12 months post-HSCT. An HCT-CI of 0 was associated with improved general QoL (FACT-G) score at 6 months compared with patients with an HCT-CI of 1 to 2 (P= .032). At 12 months post-HSCT, a pretransplantation HCT-CI ≥3 was correlated with lower QoL scores across the domains (symptom-related QoL [FACT-TOI], P= .036; FACT-G, P= .05; BMT-related QoL [FACT-BMT], P= .036). A pretransplantation KPS score of 100 versus 80 to 90 was predictive of improved QoL at 6 months post-HSCT (FACT-TOI, P = .009; FACT-G, P= .001; FACT-BMT, P= .002) but not at 1 year post-HSCT. We demonstrate that KPS and HCT-CI can predict QoL in the early post-transplantation period, with a favorable overall survival in a selected cohort of AML patients age ≥60 years.


Asunto(s)
Trasplante de Células Madre Hematopoyéticas , Leucemia Mieloide Aguda , Anciano , Humanos , Leucemia Mieloide Aguda/terapia , Persona de Mediana Edad , Calidad de Vida , Estudios Retrospectivos , Acondicionamiento Pretrasplante , Trasplante Homólogo
17.
Glob Chang Biol ; 26(4): 2220-2234, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32048447

RESUMEN

Coral reefs are declining globally as climate change and local water quality press environmental conditions beyond the physiological tolerances of holobionts-the collective of the host and its microbial symbionts. To assess the relationship between symbiont composition and holobiont stress tolerance, community diversity metrics were quantified for dinoflagellate endosymbionts (Family: Symbiodiniaceae) from eight Acropora millepora genets that thrived under or responded poorly to various stressors. These eight selected genets represent the upper and lower tails of the response distribution of 40 coral genets that were exposed to four stress treatments (and control conditions) in a 10-day experiment. Specifically, four 'best performer' coral genets were analyzed at the end of the experiment because they survived high temperature, high pCO2 , bacterial exposure, or combined stressors, whereas four 'worst performer' genets were characterized because they experienced substantial mortality under these stressors. At the end of the experiment, seven of eight coral genets mainly hosted Cladocopium symbionts, whereas the eighth genet was dominated by both Cladocopium and Durusdinium symbionts. Symbiodiniaceae alpha and beta diversity were higher in worst performing genets than in best performing genets. Symbiont communities in worst performers also differed more after stress exposure relative to their controls (based on normalized proportional differences in beta diversity), than did best performers. A generalized joint attribute model estimated the influence of host genet and treatment on Symbiodiniaceae community composition and identified strong associations among particular symbionts and host genet performance, as well as weaker associations with treatment. Although dominant symbiont physiology and function contribute to host performance, these findings emphasize the importance of symbiont community diversity and stochasticity as components of host performance. Our findings also suggest that symbiont community diversity metrics may function as indicators of resilience and have potential applications in diverse disciplines from climate change adaptation to agriculture and medicine.

18.
Biophys J ; 118(4): 885-897, 2020 02 25.
Artículo en Inglés | MEDLINE | ID: mdl-31630812

RESUMEN

The increasing prevalence of adult and adolescent obesity and its associated risk of colorectal cancer reinforces the urgent need to elucidate the underlying mechanisms contributing to the promotion of colon cancer in obese individuals. Adiponectin is an adipose tissue-derived adipokine, whose levels are reduced during obesity. Both epidemiological and preclinical data indicate that adiponectin suppresses colon tumorigenesis. We have previously demonstrated that both adiponectin and AdipoRon, a small-molecule adiponectin receptor agonist, suppress colon cancer risk in part by reducing the number of Lgr5+ stem cells in mouse colonic organoids. However, the mechanism by which the adiponectin signaling pathway attenuates colon cancer risk remains to be addressed. Here, we have hypothesized that adiponectin signaling supports colonic stem cell maintenance through modulation of the biophysical properties of the plasma membrane (PM). Specifically, we investigated the effects of adiponectin receptor activation by AdipoRon on the biophysical perturbations linked to the attenuation of Wnt-driven signaling and cell proliferation as determined by LEF luciferase reporter assay and colonic organoid proliferation, respectively. Using physicochemical sensitive dyes, Di-4-ANEPPDHQ and C-laurdan, we demonstrated that AdipoRon decreased the rigidity of the colonic cell PM. The decrease in membrane rigidity was associated with a reduction in PM free cholesterol levels and the intracellular accumulation of free cholesterol in lysosomes. These results suggest that adiponectin signaling plays a role in modulating cellular cholesterol homeostasis, PM biophysical properties, and Wnt-driven signaling. These findings are noteworthy because they may in part explain how obesity drives colon cancer progression.


Asunto(s)
Receptores de Adiponectina , Vía de Señalización Wnt , Animales , Membrana Celular , Colesterol , Ratones , Piperidinas
19.
Glob Chang Biol ; 25(10): 3294-3304, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31301206

RESUMEN

Climate change threatens organisms in a variety of interactive ways that requires simultaneous adaptation of multiple traits. Predicting evolutionary responses requires an understanding of the potential for interactions among stressors and the genetic variance and covariance among fitness-related traits that may reinforce or constrain an adaptive response. Here we investigate the capacity of Acropora millepora, a reef-building coral, to adapt to multiple environmental stressors: rising sea surface temperature, ocean acidification, and increased prevalence of infectious diseases. We measured growth rates (weight gain), coral color (a proxy for Symbiodiniaceae density), and survival, in addition to nine physiological indicators of coral and algal health in 40 coral genets exposed to each of these three stressors singly and combined. Individual stressors resulted in predicted responses (e.g., corals developed lesions after bacterial challenge and bleached under thermal stress). However, corals did not suffer substantially more when all three stressors were combined. Nor were trade-offs observed between tolerances to different stressors; instead, individuals performing well under one stressor also tended to perform well under every other stressor. An analysis of genetic correlations between traits revealed positive covariances, suggesting that selection to multiple stressors will reinforce rather than constrain the simultaneous evolution of traits related to holobiont health (e.g., weight gain and algal density). These findings support the potential for rapid coral adaptation under climate change and emphasize the importance of accounting for corals' adaptive capacity when predicting the future of coral reefs.


Asunto(s)
Antozoos , Aclimatación , Animales , Arrecifes de Coral , Concentración de Iones de Hidrógeno , Agua de Mar
20.
J Basic Microbiol ; 59(8): 834-845, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31210376

RESUMEN

A bacterium's ability to thrive in the presence of multiple environmental stressors simultaneously determines its resilience. We showed that activation of the SigB-controlled general stress response by mild environmental or energy stress provided significant cross-protection to subsequent lethal oxidative, disulfide and nitrosative stress in Bacillus subtilis. SigB activation is mediated via the stressosome and RsbP, the main conduits of environmental and energy stress, respectively. Cells exposed to mild environmental stress while lacking the major stressosome components RsbT or RsbRA were highly sensitive to subsequent oxidative stress, whereas rsbRB, rsbRC, rsbRD, and ytvA null mutants showed a spectrum of sensitivity, confirming their redundant roles and suggesting they could modulate the signals generated by environmental or oxidative stress. By contrast, cells encountering stationary phase stress required RsbP but not RsbT to survive subsequent oxidative stress. Interestingly, optimum cross-protection against nitrosative stress caused by sodium nitropruside required SigB but not the known regulators, RsbT and RsbP, suggesting an additional and as yet uncharacterized route of SigB activation independent of the known regulators. Together, these results provide mechanistic information on how B. subtilis promotes enhanced resistance against lethal oxidative stress during mild environmental and energy stress conditions.


Asunto(s)
Bacillus subtilis/fisiología , Proteínas Bacterianas/metabolismo , Estrés Oxidativo/fisiología , Fosfoproteínas Fosfatasas/metabolismo , Factor sigma/metabolismo , Transducción de Señal , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Proteínas Bacterianas/genética , Eliminación de Gen , Viabilidad Microbiana , Estrés Nitrosativo/fisiología , Fosfoproteínas Fosfatasas/genética , Fosfoproteínas/genética , Fosforilación , Proteínas Serina-Treonina Quinasas/genética , Factor sigma/genética , Transducción de Señal/genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...