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2.
BMC Womens Health ; 24(1): 157, 2024 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-38443902

RESUMEN

BACKGROUND: With the growing availability of online health resources and the widespread use of social media to better understand health conditions, people are increasingly making sense of and managing their health conditions using resources beyond their health professionals and personal networks. However, where the condition is complex and poorly understood, this can involve extensive "patient work" to locate, interpret and test the information available. The overall purpose of this study was to investigate how women with polycystic ovary syndrome (PCOS) across two healthcare systems engage with online health resources and social media to better understand this complex and poorly understood lifelong endocrine disorder. METHODS: A semi-structured interview study was conducted with women from the US ( N = 8 ) and UK ( N = 7 ) who had been diagnosed with PCOS within the previous five years. Transcribed data was analysed using a reflexive thematic analysis method. RESULTS: We highlight the information needs and information-seeking strategies women use to make sense of how PCOS affects them, to gain emotional support, and to help them find an effective treatment. We also show how women with PCOS use online health and social media resources to compare themselves to women they view as "normal" and other women with PCOS, to find their sense of "normal for me" along a spectrum of this disorder. CONCLUSION: We draw on previous models of sense-making and finding normal for other complex and sensitive health conditions to capture the nuances of making sense of PCOS. We also discuss implications for the design and use of social media to support people managing PCOS.


Asunto(s)
Síndrome del Ovario Poliquístico , Medios de Comunicación Sociales , Humanos , Femenino , Síndrome del Ovario Poliquístico/diagnóstico , Investigación Cualitativa , Personal de Salud , Recursos en Salud
3.
Arch Sex Behav ; 53(4): 1575-1589, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38302851

RESUMEN

Sex-social applications used by men who have sex with men (MSM) often provide options to disclose HIV status to encourage more positive language and reduce stigma. Yet, little research has sought to understand how in-app disclosure fields impact on disclosure motivation. We interviewed MSM living with HIV and those who self-reported being HIV-negative ( N = 27 ) in the UK and applied a hierarchical model of motivation to interpret our data. We found conflicting motivations for disclosure and point to HIV status disclosure fields having shifted disclosure norms, limiting their perceived optionality. Moreover, the pairwise and location-aware nature of these apps fails to support narrative forms of disclosure, reducing motivation. We highlight an opportunity to support users in disclosing by linking apps more explicitly to the social narratives developed through public health campaigns. This could reduce the required effort to explain "the science" behind different treatment and prevention options and promote a more consistent narrative.


Asunto(s)
Infecciones por VIH , Minorías Sexuales y de Género , Masculino , Humanos , Revelación , Homosexualidad Masculina , Infecciones por VIH/prevención & control , Estigma Social
4.
bioRxiv ; 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38328145

RESUMEN

Xenografting human cancer tissues into mice to test new cures against cancers is critical for understanding and treating the disease. However, only a few inbred strains of mice are used to study cancers, and derivatives of mainly one strain, mostly NOD/ShiLtJ, are used for therapy efficacy studies. As it has been demonstrated when human cancer cell lines or patient-derived tissues (PDX) are xenografted into mice, the neoplastic cells are human but the supporting cells that comprise the tumor (the stroma) are from the mouse. Therefore, results of studies of xenografted tissues are influenced by the host strain. We previously published that when the same neoplastic cells are xenografted into different mouse strains, the pattern of tumor growth, histology of the tumor, number of immune cells infiltrating the tumor, and types of circulating cytokines differ depending on the strain. Therefore, to better comprehend the behavior of cancer in vivo, one must xenograft multiple mouse strains. Here we describe and report a series of methods that we used to reveal the genes and proteins expressed when the same cancer cell line, MDA-MB-231, is xenografted in different hosts. First, using proteomic analysis, we show how to use the same cell line in vivo to reveal the protein changes in the neoplastic cell that help it adapt to its host. Then, we show how different hosts respond molecularly to the same cell line. We also find that using multiple strains can reveal a more suitable host than those traditionally used for a "difficult to xenograft" PDX. In addition, using complex trait genetics, we illustrate a feasible method for uncovering the alleles of the host that support tumor growth. Finally, we demonstrate that Diversity Outbred mice, the epitome of a model of mouse-strain genetic diversity, can be xenografted with human cell lines or PDX using 2-deoxy-D-glucose treatment.

5.
Am J Hosp Palliat Care ; 41(2): 150-157, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37117039

RESUMEN

Background: Extracorporeal membrane oxygenation (ECMO) has extended the survivability of critically ill patients beyond their unsupported prognosis and has widened the timeframe for making an informed decision about the goal of care. However, an extended time window for survival does not necessarily translate into a better outcome and the sustaining treatment is ultimately withdrawn in many patients. Emerging evidence has implicated the determining role of palliative care consult (PCC) in direction of the care that critically ill patients receive. Objective: To evaluate the impact of PCC in withdrawal of life-sustaining treatment (WOLST) among critically ill patients, who were placed on venovenous ECMO (VV-ECMO) at the intensive care unit (ICU) of a tertiary care hospital. Methods: In a retrospective observational study, electronic medical records of 750 patients admitted to the ICU of our hospital between January 1, 2015, and October 31, 2021, were reviewed. Data was collected for patients on VV-ECMO, for whom WOLST was withdrawn during the ICU stay. Clinical characteristics and the underlying reasons for WOLST were compared between those who received PCC (PCC group) and those who did not (non-PCC group). Results: A total of 95 patients were included in our analysis, 63 in the PCC group and 32 in the non-PCC group. The average age of the study population was 48.8 ± 12.6 years, and 64.2% were male. There was no statistically significant difference between the two groups in terms of demographics or clinical characteristics at the time of ICU admission. The average duration of ICU stay and VV-ECMO were 14.1 ± 19.9 days and 9.4 ± 16.6 days, respectively. The number of PCC visits was correlated with the length of ICU stay. The average duration of ICU stay (40.3 ± 33.2 days vs 27.8 ± 19.3 days, P = .05) and ECMO treatment (31.9 ± 27 days vs 18.6 ± 16.1 days, P = .01) were significantly longer in patients receiving PCC than those not receiving PCC. However, the frequency of life sustaining measures or the underlying reasons for WOLST did not significantly differ between the two groups (P > .05). Conclusion: Among ICU patients requiring ECMO support, longer duration of ICU stay and treatment with a higher number of life-sustaining measures seemed to be correlated with the number of PCC visits. The underlying reasons for WOLST seem not to be affected by PCC.


Asunto(s)
Oxigenación por Membrana Extracorpórea , Humanos , Masculino , Adulto , Persona de Mediana Edad , Femenino , Estudios Retrospectivos , Estudios de Casos y Controles , Cuidados Paliativos , Enfermedad Crítica/terapia , Unidades de Cuidados Intensivos , Derivación y Consulta
6.
Proc Biol Sci ; 290(2007): 20231403, 2023 09 27.
Artículo en Inglés | MEDLINE | ID: mdl-37727091

RESUMEN

Symbiotic mutualisms are essential to ecosystems and numerous species across the tree of life. For reef-building corals, the benefits of their association with endosymbiotic dinoflagellates differ within and across taxa, and nutrient exchange between these partners is influenced by environmental conditions. Furthermore, it is widely assumed that corals associated with symbionts in the genus Durusdinium tolerate high thermal stress at the expense of lower nutrient exchange to support coral growth. We traced both inorganic carbon (H13CO3-) and nitrate (15NO3-) uptake by divergent symbiont species and quantified nutrient transfer to the host coral under normal temperatures as well as in colonies exposed to high thermal stress. Colonies representative of diverse coral taxa associated with Durusdinium trenchii or Cladocopium spp. exhibited similar nutrient exchange under ambient conditions. By contrast, heat-exposed colonies with D. trenchii experienced less physiological stress than conspecifics with Cladocopium spp. while high carbon assimilation and nutrient transfer to the host was maintained. This discovery differs from the prevailing notion that these mutualisms inevitably suffer trade-offs in physiological performance. These findings emphasize that many host-symbiont combinations adapted to high-temperature equatorial environments are high-functioning mutualisms; and why their increased prevalence is likely to be important to the future productivity and stability of coral reef ecosystems.


Asunto(s)
Antozoos , Dinoflagelados , Termotolerancia , Animales , Simbiosis , Ecosistema , Carbono , Nutrientes
7.
Proc Biol Sci ; 290(2003): 20231021, 2023 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-37465983

RESUMEN

The flexibility to associate with more than one symbiont may considerably expand a host's niche breadth. Coral animals and dinoflagellate micro-algae represent one of the most functionally integrated and widespread mutualisms between two eukaryotic partners. Symbiont identity greatly affects a coral's ability to cope with extremes in temperature and light. Over its broad distribution across the Eastern Pacific, the ecologically dominant branching coral, Pocillopora grandis, depends on mutualisms with the dinoflagellates Durusdinium glynnii and Cladocopium latusorum. Measurements of skeletal growth, calcification rates, total mass increase, calyx dimensions, reproductive output and response to thermal stress were used to assess the functional performance of these partner combinations. The results show both host-symbiont combinations displayed similar phenotypes; however, significant functional differences emerged when exposed to increased temperatures. Negligible physiological differences in colonies hosting the more thermally tolerant D. glynnii refute the prevailing view that these mutualisms have considerable growth tradeoffs. Well beyond the Eastern Pacific, pocilloporid colonies with D. glynnii are found across the Pacific in warm, environmentally variable, near shore lagoonal habitats. While rising ocean temperatures threaten the persistence of contemporary coral reefs, lessons from the Eastern Pacific indicate that co-evolved thermally tolerant host-symbiont combinations are likely to expand ecologically and spread geographically to dominate reef ecosystems in the future.


Asunto(s)
Antozoos , Dinoflagelados , Animales , Antozoos/fisiología , Ecosistema , Arrecifes de Coral , Temperatura , Dinoflagelados/fisiología , Simbiosis/fisiología
8.
J Phycol ; 59(4): 698-711, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37126002

RESUMEN

The existence of widespread species with the capacity to endure diverse, or variable, environments are of importance to ecological and genetic research, and conservation. Such "ecological generalists" are more likely to have key adaptations that allow them to better tolerate the physiological challenges of rapid climate change. Reef-building corals are dependent on endosymbiotic dinoflagellates (Family: Symbiodiniaceae) for their survival and growth. While these symbionts are biologically diverse, certain genetic types appear to have broad geographic distributions and are mutualistic with various host species from multiple genera and families in the order Scleractinia that must acquire their symbionts through horizontal transmission. Despite the considerable ecological importance of putative host-generalist symbionts, they lack formal species descriptions. In this study, we used molecular, ecological, and morphological evidence to verify the existence of five new host-generalist species in the symbiodiniacean genus Cladocopium. Their geographic distribution and prevalence among host communities corresponds to prevailing environmental conditions at both regional and local scales. The influence that each species has on host physiology may partially explain regional differences in thermal sensitivities among coral communities. The potential increased prevalence of a generalist species that endures environmental instability is a consequential ecological response to warming oceans. Large-scale shifts in symbiont dominance could ensure reef coral persistence and productivity in the near term. Ultimately, these formal designations should advance scientific communication and generate informed research questions on the physiology and ecology of coral-dinoflagellate mutualisms.


Asunto(s)
Antozoos , Dinoflagelados , Animales , Antozoos/fisiología , Arrecifes de Coral , Dinoflagelados/genética , Simbiosis , Aclimatación
9.
ACS Appl Mater Interfaces ; 15(8): 11092-11098, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36791283

RESUMEN

Liquid crystalline elastomers (LCEs) are shape-changing materials that exhibit large deformations in response to applied stimuli. Local control of the orientation of LCEs spatially directs the deformation of these materials to realize a spontaneous shape change in response to stimuli. Prior approaches to shape programming in LCEs utilize patterning techniques that involve the detailed inscription of spatially varying nematic fields to produce sheets. These patterned sheets deform into elaborate geometries with complex Gaussian curvatures. Here, we present an alternative approach to realize shape-morphing in LCEs where spatial patterning of the crosslink density locally regulates the material deformation magnitude on either side of a prescribed interface curve. We also present a simple mathematical model describing the behavior of these materials. Further experiments coupled with the mathematical model demonstrate the control of the sign of Gaussian curvature, which is used in combination with heat transfer effects to design LCEs that self-clean as a result of temperature-dependent actuation properties.

10.
Sci Rep ; 13(1): 1355, 2023 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-36693980

RESUMEN

Coral reefs are declining worldwide, yet some coral populations are better adapted to withstand reductions in pH and the rising frequency of marine heatwaves. The nearshore reef habitats of Palau, Micronesia are a proxy for a future of warmer, more acidic oceans. Coral populations in these habitats can resist, and recover from, episodes of thermal stress better than offshore conspecifics. To explore the physiological basis of this tolerance, we compared tissue biomass (ash-free dry weight cm-2), energy reserves (i.e., protein, total lipid, carbohydrate content), and several important lipid classes in six coral species living in both offshore and nearshore environments. In contrast to expectations, a trend emerged of many nearshore colonies exhibiting lower biomass and energy reserves than colonies from offshore sites, which may be explained by the increased metabolic demand of living in a warmer, acidic, environment. Despite hosting different dinoflagellate symbiont species and having access to contrasting prey abundances, total lipid and lipid class compositions were similar in colonies from each habitat. Ultimately, while the regulation of colony biomass and energy reserves may be influenced by factors, including the identity of the resident symbiont, kind of food consumed, and host genetic attributes, these independent processes converged to a similar homeostatic set point under different environmental conditions.


Asunto(s)
Antozoos , Animales , Antozoos/fisiología , Biomasa , Arrecifes de Coral , Ecosistema , Lípidos
11.
PeerJ ; 10: e14176, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36345483

RESUMEN

Coral reefs are declining worldwide primarily because of bleaching and subsequent mortality resulting from thermal stress. Currently, extensive efforts to engage in more holistic research and restoration endeavors have considerably expanded the techniques applied to examine coral samples. Despite such advances, coral bleaching and restoration studies are often conducted within a specific disciplinary focus, where specimens are collected, preserved, and archived in ways that are not always conducive to further downstream analyses by specialists in other disciplines. This approach may prevent the full utilization of unexpended specimens, leading to siloed research, duplicative efforts, unnecessary loss of additional corals to research endeavors, and overall increased costs. A recent US National Science Foundation-sponsored workshop set out to consolidate our collective knowledge across the disciplines of Omics, Physiology, and Microscopy and Imaging regarding the methods used for coral sample collection, preservation, and archiving. Here, we highlight knowledge gaps and propose some simple steps for collecting, preserving, and archiving coral-bleaching specimens that can increase the impact of individual coral bleaching and restoration studies, as well as foster additional analyses and future discoveries through collaboration. Rapid freezing of samples in liquid nitrogen or placing at -80 °C to -20 °C is optimal for most Omics and Physiology studies with a few exceptions; however, freezing samples removes the potential for many Microscopy and Imaging-based analyses due to the alteration of tissue integrity during freezing. For Microscopy and Imaging, samples are best stored in aldehydes. The use of sterile gloves and receptacles during collection supports the downstream analysis of host-associated bacterial and viral communities which are particularly germane to disease and restoration efforts. Across all disciplines, the use of aseptic techniques during collection, preservation, and archiving maximizes the research potential of coral specimens and allows for the greatest number of possible downstream analyses.


Asunto(s)
Antozoos , Blanqueamiento de los Corales , Animales , Arrecifes de Coral , Antozoos/microbiología
12.
Dis Model Mech ; 15(9)2022 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-36037073

RESUMEN

The lack of genetically diverse preclinical animal models in basic biology and efficacy testing has been cited as a potential cause of failure in clinical trials. We developed and characterized five diverse RAG1 null mouse strains as models that allow xenografts to grow. In these strains, we characterized the growth of breast cancer, leukemia and glioma cell lines. We found a wide range of growth characteristics that were far more dependent on strain than tumor type. For the breast cancer cell line, we characterized the spectrum of xenograft/tumor growth at structural, histological, cellular and molecular levels across each strain, and found that each strain captures unique structural components of the stroma. Furthermore, we showed that the increase in tumor-infiltrating myeloid CD45+ cells and the amount of circulating cytokine IL-6 and chemokine KC (also known as CXCL1) is associated with a higher tumor size in different strains. This resource is available to study established human xenografts, as well as difficult-to-xenograft tumors and growth of hematopoietic stems cells, and to decipher the role of myeloid cells in the development of spontaneous cancers.


Asunto(s)
Neoplasias de la Mama , Animales , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Línea Celular Tumoral , Modelos Animales de Enfermedad , Femenino , Xenoinjertos , Humanos , Ratones , Ratones Noqueados , Trasplante Heterólogo , Ensayos Antitumor por Modelo de Xenoinjerto
13.
Proc Math Phys Eng Sci ; 478(2262): 20220230, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35814332

RESUMEN

A flat sheet programmed with a planar pattern of spontaneous shape change will morph into a curved surface. Such metric mechanics is seen in growing biological sheets, and may be engineered in actuating soft matter sheets such as phase-changing liquid crystal elastomers (LCEs), swelling gels and inflating baromorphs. Here, we show how to combine multiple patterns in a sheet by stitching regions of different shape changes together piecewise along interfaces. This approach allows simple patterns to be used as building blocks, and enables the design of multi-material or active/passive sheets. We give a general condition for an interface to be geometrically compatible, and explore its consequences for LCE/LCE, gel/gel and active/passive interfaces. In contraction/elongation systems such as LCEs, we find an infinite set of compatible interfaces between any pair of patterns along which the metric is discontinuous, and a finite number across which the metric is continuous. As an example, we find all possible interfaces between pairs of LCE logarithmic spiral patterns. By contrast, in isotropic systems such as swelling gels, only a finite number of continuous interfaces are available, greatly limiting the potential of stitching. In both continuous and discontinuous cases, we find the stitched interfaces generically carry singular Gaussian curvature, leading to intrinsically curved folds in the actuated surface. We give a general expression for the distribution of this curvature, and a more specialized form for interfaces in LCE patterns. The interfaces thus also have rich geometric and mechanical properties in their own right.

14.
Glob Chang Biol ; 28(14): 4229-4250, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35475552

RESUMEN

The global impacts of climate change are evident in every marine ecosystem. On coral reefs, mass coral bleaching and mortality have emerged as ubiquitous responses to ocean warming, yet one of the greatest challenges of this epiphenomenon is linking information across scientific disciplines and spatial and temporal scales. Here we review some of the seminal and recent coral-bleaching discoveries from an ecological, physiological, and molecular perspective. We also evaluate which data and processes can improve predictive models and provide a conceptual framework that integrates measurements across biological scales. Taking an integrative approach across biological and spatial scales, using for example hierarchical models to estimate major coral-reef processes, will not only rapidly advance coral-reef science but will also provide necessary information to guide decision-making and conservation efforts. To conserve reefs, we encourage implementing mesoscale sanctuaries (thousands of km2 ) that transcend national boundaries. Such networks of protected reefs will provide reef connectivity, through larval dispersal that transverse thermal environments, and genotypic repositories that may become essential units of selection for environmentally diverse locations. Together, multinational networks may be the best chance corals have to persist through climate change, while humanity struggles to reduce emissions of greenhouse gases to net zero.


Asunto(s)
Antozoos , Cambio Climático , Animales , Antozoos/fisiología , Arrecifes de Coral , Ecosistema
15.
Anesth Analg ; 135(1): 6-19, 2022 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-35389378

RESUMEN

Patient safety is a core principle of anesthesia care worldwide. The specialty of anesthesiology has been a leader in medicine for the past half century in pursuing patient safety research and implementing standards of care and systematic improvements in processes of care. Together, these efforts have dramatically reduced patient harm associated with anesthesia. However, improved anesthesia patient safety has not been uniformly obtained worldwide. There are unique differences in patient safety outcomes between countries and regions in the world. These differences are often related to factors such as availability, support, and use of health care resources, trained personnel, patient safety outcome data collection efforts, standards of care, and cultures of safety and teamwork in health care facilities. This article provides insights from national anesthesia society leaders from 13 countries around the world. The countries they represent are diverse geographically and in health care resources. The authors share their countries' current and future initiatives in anesthesia patient safety. Ten major patient safety issues are common to these countries, with several of these focused on the importance of extending initiatives into the full perioperative as well as intraoperative environments. These issues may be used by anesthesia leaders around the globe to direct collaborative efforts to improve the safety of patients undergoing surgery and anesthesia in the coming decade.


Asunto(s)
Anestesia , Anestesiología , Anestesia/efectos adversos , Humanos , Seguridad del Paciente
18.
J Extra Corpor Technol ; 54(3): 235-238, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36742217

RESUMEN

COVID-19 morbidity and mortality are not equivalent to other etiologies of acute respiratory distress syndrome (ARDS) as fulminant activation of coagulation can occur, thereby resulting in widespread microvascular thrombosis and consumption of coagulation factors. A 53-year-old female presented to an emergency center on two occasions with progressive gastrointestinal and respiratory symptoms. She was diagnosed with COVID-19 pneumonia and admitted to a satellite intensive care unit with hypoxemic respiratory failure. She was intubated and mechanically ventilated, but her ARDS progressed over the next 48 hours. The patient was emergently cannulated for veno-venous extracorporeal membrane oxygenation (V-V ECMO) and transferred to our hospital. She was in profound shock requiring multiple vasopressors for hemodynamic support with worsening clinical status on arrival. On bedside echocardiography, she was found to have a massive pulmonary embolism with clot-in-transit visualized in the right atrium and right ventricular outflow tract. After a multidisciplinary discussion, systemic thrombolytic therapy was administered. The patient's hemodynamics improved and vasopressors were discontinued. This case illustrates the utility of bedside echocardiography in shock determination, the need for continued vigilance in the systematic evaluation of unstable patients in the intensive care unit, and the use of systemic thrombolytics during V-V ECMO in a novel disease process with evolving understanding.


Asunto(s)
COVID-19 , Oxigenación por Membrana Extracorpórea , Embolia Pulmonar , Síndrome de Dificultad Respiratoria , Trombosis , Humanos , Femenino , Persona de Mediana Edad , Oxigenación por Membrana Extracorpórea/métodos , COVID-19/complicaciones , COVID-19/terapia , Embolia Pulmonar/etiología , Embolia Pulmonar/terapia , Síndrome de Dificultad Respiratoria/etiología , Síndrome de Dificultad Respiratoria/terapia , Terapia Trombolítica
19.
Anesthesiology ; 135(6): 963-974, 2021 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-34666350

RESUMEN

Ellison C. Pierce, Jr., M.D., and a small number of specialty leaders and scientists formed a remarkable, diverse team in the mid-1980s to address a dual crisis: a safety crisis for anesthetized patients and a medical malpractice insurance crisis for anesthesiologists. This cohesive team's efforts led to the formation of the Anesthesia Patient Safety Foundation, the American Society of Anesthesiologists's Committees on Standards of Care and on Patient Safety and Risk Management, and the society's Closed Claims Project. The commonality of leaders and members of the Anesthesia Patient Safety Foundation and American Society of Anesthesiologists initiatives provided the strong coordination needed for their efforts to effect change, introduce standards of care and practice parameters, obtain financial support needed to grow patient safety-oriented new knowledge, integrate industry and other relevant leaders outside of anesthesiology, and involve all anesthesia professions. By implementing successful patient safety initiatives, they promoted the recognition that anesthesiology and patient safety are inextricably linked.


Asunto(s)
Anestesia/normas , Anestesiología/normas , Seguridad del Paciente/normas , Sociedades Médicas/normas , Anestesia/tendencias , Anestesiología/tendencias , Humanos , Liderazgo , Sociedades Médicas/tendencias , Estados Unidos
20.
PLoS One ; 16(10): e0259161, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34705875

RESUMEN

There is little information on the impacts of climate change on resource partitioning for mixotrophic phytoplankton. Here, we investigated the hypothesis that light interacts with temperature and CO2 to affect changes in growth and cellular carbon and nitrogen content of the mixotrophic dinoflagellate, Karlodinium veneficum, with increasing cellular carbon and nitrogen content under low light conditions and increased growth under high light conditions. Using a multifactorial design, the interactive effects of light, temperature and CO2 were investigated on K. veneficum at ambient temperature and CO2 levels (25°C, 375 ppm), high temperature (30°C, 375 ppm CO2), high CO2 (30°C, 750 ppm CO2), or a combination of both high temperature and CO2 (30°C, 750 ppm CO2) at low light intensities (LL: 70 µmol photons m-2 s-2) and light-saturated conditions (HL: 140 µmol photons m-2 s-2). Results revealed significant interactions between light and temperature for all parameters. Growth rates were not significantly different among LL treatments, but increased significantly with temperature or a combination of elevated temperature and CO2 under HL compared to ambient conditions. Particulate carbon and nitrogen content increased in response to temperature or a combination of elevated temperature and CO2 under LL conditions, but significantly decreased in HL cultures exposed to elevated temperature and/or CO2 compared to ambient conditions at HL. Significant increases in C:N ratios were observed only in the combined treatment under LL, suggesting a synergistic effect of temperature and CO2 on carbon assimilation, while increases in C:N under HL were driven only by an increase in CO2. Results indicate light-driven variations in growth and nutrient acquisition strategies for K. veneficum that may benefit this species under anticipated climate change conditions (elevated light, temperature and pCO2) while also affecting trophic transfer efficiency during blooms of this species.


Asunto(s)
Biomasa , Dinoflagelados/metabolismo , Eutrofización , Dióxido de Carbono/metabolismo , Dinoflagelados/crecimiento & desarrollo , Calor , Nitrógeno/metabolismo , Luz Solar
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