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1.
Ann Bot ; 133(1): 29-40, 2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-37463436

RESUMO

BACKGROUND AND AIMS: The increased likelihood and severity of storm events has brought into focus the role of coastal ecosystems in provision of shoreline protection by attenuating wave energy. Canopy-forming kelps, including giant kelp (Macrocystis pyrifera), are thought to provide this ecosystem service, but supporting data are extremely limited. Previous in situ examinations relied mostly on comparisons between nominally similar sites with and without kelp. Given that other factors (especially seafloor bathymetry and topographic features) often differ across sites, efforts to isolate the effects of kelp on wave energy propagation confront challenges. In particular, it can be difficult to distinguish wave energy dissipation attributable to kelp from frictional processes at the seabed that often covary with the presence of kelp. Here, we use an ecological transition from no kelp to a full forest, at a single site with static bathymetry, to resolve unambiguously the capacity of giant kelp to damp waves. METHODS: We measured waves within and outside rocky reef habitat, in both the absence and the presence of giant kelp, at Marguerite Reef, Palos Verdes, CA, USA. Nested within a broader kelp restoration project, this site transitioned from a bare state to one supporting a fully formed forest (density of 8 stipes m-2). We quantified, as a function of incident wave conditions, the decline in wave energy flux attributable to the presence of kelp, as waves propagated from outside and into reef habitat. KEY RESULTS: The kelp forest damped wave energy detectably, but to a modest extent. Interactions with the seabed alone reduced wave energy flux, on average, by 12 ±â€…1.4 % over 180 m of travel. The kelp forest induced an additional 7 ±â€…1.2 % decrease. Kelp-associated declines in wave energy flux were slightly greater for waves of longer periods and smaller wave heights. CONCLUSIONS: Macrocystis pyrifera forests have a limited, albeit measurable, capacity to enhance shoreline protection from nearshore waves. Expectations that giant kelp forests, whether extant or enhanced through restoration, have substantial impacts on wave-induced coastal erosion might require re-evaluation.


Assuntos
Kelp , Macrocystis , Ecossistema , Florestas , Reprodução
2.
Science ; 380(6651): 1216-1218, 2023 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-37347865

RESUMO

A fatigue-resistant mollusk hinge could in spire the development of new materials.


Assuntos
Cerâmica , Moluscos , Teste de Materiais , Propriedades de Superfície
3.
Pharmaceutics ; 15(2)2023 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-36839835

RESUMO

The present article exemplifies the application of the concept of quality by design (QbD) for the systematic development of a nanoparticulate imiquimod (IMQ) emulsion gel formulation as an investigational medicinal product (IMP) for evaluation in an academic phase-I/II clinical trial for the treatment of actinic keratosis (AK) against the comparator Aldara (EudraCT: 2015-002203-28). The design of the QbD elements of a quality target product profile (QTPP) enables the identification of the critical quality attributes (CQAs) of the drug product as the content of IMQ, the particle-size distribution, the pH, the rheological properties, the permeation rate and the chemical, physical and microbiological stability. Critical material attributes (CMAs) and critical process parameters (CPPs) are identified by using a risk-based approach in an Ishikawa diagram and in a risk-estimation matrix. In this study, the identified CPPs of the wet media ball-milling process's milling time and milling speed are evaluated in a central composite design of experiments (DoEs) approach, revealing criticality for both factors for the resulting mean particle size, while only the milling time is significantly affecting the polydispersity. To achieve a mean particle size in the range of 300-400 nm with a minimal PdI, the optimal process conditions are found to be 650 rpm for 135 min. Validating the model reveals a good correlation between the predicted and observed values. Adequate control strategies were implemented for intermediate products as in-process controls (IPCs) and quality control (QC) tests of the identified CQAs. The IPC and QC data from 13 "IMI-Gel" batches manufactured in adherence to good manufacturing practice (GMP) reveal consistent quality with minimal batch-to-batch variability.

4.
Integr Org Biol ; 4(1): obac037, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36003414

RESUMO

Accurate forecasting of organismal responses to climate change requires a deep mechanistic understanding of how physiology responds to present-day variation in the physical environment. However, the road to physiological enlightenment is fraught with complications: predictable environmental fluctuations of any single factor are often accompanied by substantial stochastic variation and rare extreme events, and several factors may interact to affect physiology. Lacking sufficient knowledge of temporal patterns of co-variation in multiple environmental stressors, biologists struggle to design and implement realistic and relevant laboratory experiments. In this study, we directly address these issues, using measurements of the thermal tolerance of freshly collected animals and long-term field records of environmental conditions to explore how the splash-pool copepod Tigriopus californicus adjusts its physiology as its environment changes. Salinity and daily maximum temperature-two dominant environmental stressors experienced by T. californicus-are extraordinarily variable and unpredictable more than 2-3 days in advance. However, they substantially co-vary such that when temperature is high salinity is also likely to be high. Copepods appear to take advantage of this correlation: median lethal temperature of field-collected copepods increases by 7.5°C over a roughly 120 parts-per-thousand range of ambient salinity. Complementary laboratory experiments show that exposure to a single sublethal thermal event or to an abrupt shift in salinity also elicits rapid augmentation of heat tolerance via physiological plasticity, although the effect of salinity dwarfs that of temperature. These results suggest that T. californicus's physiology keeps pace with the rapid, unpredictable fluctuations of its hypervariable physical environment by responding to the cues provided by recent sublethal stress and, more importantly, by leveraging the mechanistic cross-talk between responses to salinity and heat stress.

5.
J Exp Biol ; 225(9)2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-35388895

RESUMO

Thermal performance curves are commonly used to investigate the effects of heat acclimation on thermal tolerance and physiological performance. However, recent work indicates that the metrics of these curves heavily depend on experimental design and may be poor predictors of animal survival during heat events in the field. In intertidal mussels, cardiac thermal performance (CTP) tests have been widely used as indicators of animals' acclimation or acclimatization state, providing two indices of thermal responses: critical temperature (Tcrit; the temperature above which heart rate abruptly declines) and flatline temperature (Tflat; the temperature where heart rate ceases). Despite the wide use of CTP tests, it remains largely unknown how Tcrit and Tflat change within a single individual after heat acclimation, and whether changes in these indices can predict altered survival in the field. Here, we addressed these issues by evaluating changes in CTP indices in the same individuals before and after heat acclimation. For control mussels, merely reaching Tcrit was not lethal, whereas remaining at Tcrit for ≥10 min was lethal. Heat acclimation significantly increased Tcrit only in mussels with an initially low Tcrit (<35°C), but improved their survival time above Tcrit by 20 min on average. Tflat increased by ∼1.6°C with heat acclimation, but it is unlikely that increased Tflat improves survival in the field. In summary, Tcrit and Tflat per se may fall short of providing quantitative indices of thermal tolerance in mussels; instead, a combination of Tcrit and tolerance time at temperatures ≥Tcrit better defines changes in thermal tolerance with heat acclimation.


Assuntos
Mytilus , Animais , Aclimatação , Temperatura Alta , Mytilus/fisiologia , Temperatura
6.
Ecol Evol ; 12(3): e8747, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35356556

RESUMO

Collective behaviors in biological systems such as coordinated movements have important ecological and evolutionary consequences. While many studies examine within-species variation in collective behavior, explicit comparisons between functionally similar species from different taxonomic groups are rare. Therefore, a fundamental question remains: how do collective behaviors compare between taxa with morphological and physiological convergence, and how might this relate to functional ecology and niche partitioning? We examined the collective motion of two ecologically similar species from unrelated clades that have competed for pelagic predatory niches for over 500 million years-California market squid, Doryteuthis opalescens (Mollusca) and Pacific sardine, Sardinops sagax (Chordata). We (1) found similarities in how groups of individuals from each species collectively aligned, measured by angular deviation, the difference between individual orientation and average group heading. We also (2) show that conspecific attraction, which we approximated using nearest neighbor distance, was greater in sardine than squid. Finally, we (3) found that individuals of each species explicitly matched the orientation of groupmates, but that these matching responses were less rapid in squid than sardine. Based on these results, we hypothesize that information sharing is a comparably important function of social grouping for both taxa. On the other hand, some capabilities, including hydrodynamically conferred energy savings and defense against predators, could stem from taxon-specific biology.

7.
Am Nat ; 199(4): 523-550, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35324378

RESUMO

AbstractThe distributions of marine ectotherms are governed by physiological sensitivities to long-term trends in seawater temperature and dissolved oxygen. Short-term variability in these parameters has the potential to facilitate rapid range expansions, and the resulting ecological and socioeconomic consequences may portend those of future marine communities. Here, we combine physiological experiments with ecological and demographic surveys to assess the causes and consequences of sudden but temporary poleward range expansions of a marine ectotherm with considerable life history plasticity (California market squid, Doryteuthis opalescens). We show that sequential factors related to resource accessibility in the core range-the buildup of large populations as a result of competitive release and climate-associated temperature increase and oxygen loss that constrain aerobic activity-may drive these expansions. We also reveal that poleward range expansion alters the body size-and therefore trophic role-of invading populations, with potential negative implications for socioeconomically valuable resident species. To help forecast rapid range expansions of marine ectotherms, we advocate that research efforts focus on factors impacting resource accessibility in core ranges. Determining how environmental conditions in receiving ecosystems affect body size and how body size is related to trophic role will help refine estimates of the impacts of future marine communities.


Assuntos
Ecossistema , Oxigênio , Animais , Demografia , Feminino , Gravidez , Água do Mar , Temperatura
8.
Ann Rev Mar Sci ; 14: 25-48, 2022 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-34314598

RESUMO

To better understand life in the sea, marine scientists must first quantify how individual organisms experience their environment, and then describe how organismal performance depends on that experience. In this review, we first explore marine environmental variation from the perspective of pelagic organisms, the most abundant life forms in the ocean. Generation time, the ability to move relative to the surrounding water (even slowly), and the presence of environmental gradients at all spatial scales play dominant roles in determining the variation experienced by individuals, but this variation remains difficult to quantify. We then use this insight to critically examine current understanding of the environmental physiology of pelagic marine organisms. Physiologists have begun to grapple with the complexity presented by environmental variation, and promising frameworks exist for predicting and/or interpreting the consequences for physiological performance. However, new technology needs to be developed and much difficult empirical work remains, especially in quantifying response times to environmental variation and the interactions among multiple covarying factors. We call on the field of global-change biology to undertake these important challenges.


Assuntos
Organismos Aquáticos , Organismos Aquáticos/fisiologia , Oceanos e Mares
9.
COPD ; 18(1): 91-100, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33302718

RESUMO

Tiotropium and olodaterol are mainstay treatments for chronic obstructive pulmonary disease (COPD) and yield important clinical improvements, especially when used in fixed-dose combination. Whilst previous studies have shown consistent delivery of tiotropium to the lungs with the Respimat® inhaler, no such study has been carried out for olodaterol or the components of their fixed-dose combination (TIO/OLO). Combining in vitro and in silico models, we measured the amount of drug retained in the mouth-throat area, entering the trachea and reaching the lung periphery. We applied a hybrid deposition model that considered the experimentally determined output of an Alberta throat model (in vitro - dose to lung) combined with a computational fluid dynamic model of the lungs (in silico). Regardless of the COPD breathing pattern, ≥50% of the nominal dose of either tiotropium, olodaterol, or TIO and OLO in the fixed-dose combination reached the lung. Of the dose reaching the lungs, greater than 50% is deposited in the lung periphery (from generation 8 onwards). Our study demonstrated that aerosol delivery via the Respimat inhaler achieved high deposition deep into the lung periphery with all formulations evaluated.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Administração por Inalação , Benzoxazinas , Broncodilatadores/uso terapêutico , Simulação por Computador , Humanos , Pulmão , Nebulizadores e Vaporizadores , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Brometo de Tiotrópio/uso terapêutico
10.
Proc Biol Sci ; 287(1940): 20202561, 2020 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-33290677

RESUMO

Climate change is not only causing steady increases in average global temperatures but also increasing the frequency with which extreme heating events occur. These extreme events may be pivotal in determining the ability of organisms to persist in their current habitats. Thus, it is important to understand how quickly an organism's heat tolerance can be gained and lost relative to the frequency with which extreme heating events occur in the field. We show that the California mussel, Mytilus californianus-a sessile intertidal species that experiences extreme temperature fluctuations and cannot behaviourally thermoregulate-can quickly (in 24-48 h) acquire improved heat tolerance after exposure to a single sublethal heat-stress bout (2 h at 30 or 35°C) and then maintain this improved tolerance for up to three weeks without further exposure to elevated temperatures. This adaptive response improved survival rates by approximately 75% under extreme heat-stress bouts (2 h at 40°C). To interpret these laboratory findings in an ecological context, we evaluated 4 years of mussel body temperatures recorded in the field. The majority (approx. 64%) of consecutive heat-stress bouts were separated by 24-48 h, but several consecutive heat bouts were separated by as much as 22 days. Thus, the ability of M. californianus to maintain improved heat tolerance for up to three weeks after a single sublethal heat-stress bout significantly improves their probability of survival, as approximately 33% of consecutive heat events are separated by 3-22 days. As a sessile animal, mussels likely evolved the capability to rapidly gain and slowly lose heat tolerance to survive the intermittent, and often unpredictable, heat events in the intertidal zone. This adaptive strategy will likely prove beneficial under the extreme heat events predicted with climate change.


Assuntos
Aclimatação , Resposta ao Choque Térmico , Temperatura Alta , Mytilus/fisiologia , Animais , Temperatura Corporal , California , Mudança Climática , Ecossistema , Estações do Ano , Temperatura , Termotolerância
11.
J Exp Biol ; 223(Pt 13)2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32457061

RESUMO

Climate change is increasing the temperature variability animals face, and thermal acclimatization allows animals to adjust adaptively to this variability. Although the rate of heat acclimatization has received some study, little is known about how long these adaptive changes remain without continuing exposure to heat stress. This study explored the rate at which field acclimatization states are lost when temperature variability is minimized during constant submersion. California mussels (Mytilus californianus) with different acclimatization states were collected from high- and low-zone sites (∼12 versus ∼5°C daily temperature ranges, respectively) and then kept submerged at 15°C for 8 weeks. Each week, the cardiac thermal performance of mussels was measured as a metric of acclimatization state: critical (Tcrit) and flatline (Tflat) temperatures were recorded. Over 8 weeks of constant submersion, the mean Tcrit of high-zone mussels decreased by 1.07°C from baseline, but low-zone mussels' mean Tcrit was unchanged. High- and low-zone mussels' mean maximum heart rate (HR) and resting HR decreased ∼12 and 35%, respectively. Tflat was unchanged in both groups. These data suggest that Tcrit and HR are more physiologically plastic in response to the narrowing of an animal's daily temperature range than Tflat is, and that an animal's prior acclimatization state (high versus low) influences the acclimatory capacity of Tcrit Approximately 2 months were required for the cardiac thermal performance of the high-zone mussels to reach that of the low-zone mussels, suggesting that acclimatization to high and variable temperatures may persist long enough to enable these animals to cope with intermittent bouts of heat stress.


Assuntos
Aclimatação , Mytilus , Animais , Mudança Climática , Temperatura Alta , Temperatura
12.
Fish Shellfish Immunol ; 100: 70-79, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32135339

RESUMO

Hemocytes are immune cells in the hemolymph of invertebrates that play multiple roles in response to stressors; hemocyte mortality can thus serve as an indicator of overall animal health. However, previous research has often analyzed hemolymph samples pooled from several individuals, which precludes tracking individual responses to stressors over time. The ability to track individuals is important, however, because large inter-individual variation in response to stressors can confound the interpretation of pooled samples. Here, we describe protocols for analysis of inter- and intra-individual variability in hemocyte mortality across repeated hemolymph samples of California mussels, Mytilus californianus, free from typical abiotic stressors. To assess individual variability in hemocyte mortality with serial sampling, we created four groups of 15 mussels each that were repeatedly sampled four times: at baseline (time zero) and three subsequent times separated by either 24, 48, 72, or 168 h. Hemocyte mortality was assessed by fluorescence-activated cell sorting (FACS) of cells stained with propidium iodide. Our study demonstrates that hemolymph can be repeatedly sampled from individual mussels without mortality; however, there is substantial inter- and intra-individual variability in hemocyte mortality through time that is partially dependent on the sampling interval. Across repeated samples, individual mussels' hemocyte mortality had, on average, a range of ~6% and a standard deviation of ~3%, which was minimized with sampling periods ≥72 h apart. Due to this intra-individual variability, obtaining ≥2 samples from a specimen will more accurately establish an individual's baseline. Pooled-sample means were similar to individual-sample means; however, pooled samples masked the individual variation in each group. Overall, these data lay the foundation for future work exploring individual mussels' temporal responses to various stressors on a cellular level.


Assuntos
Hemócitos/patologia , Mytilus/citologia , Manejo de Espécimes/métodos , Animais , Sobrevivência Celular , Citometria de Fluxo , Hemócitos/imunologia , Hemolinfa/citologia , Mytilus/imunologia , Alimentos Marinhos , Estresse Fisiológico
13.
Proc Biol Sci ; 287(1918): 20192333, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31937220

RESUMO

Accelerating shifts in global climate have focused the attention of ecologists and physiologists on extreme environmental events. However, the dynamic process of physiological acclimatization complicates study of these events' consequences. Depending on the range of plasticity and the amplitude and speed of environmental variation, physiology can be either in tune with the surroundings or dangerously out of synch. We implement a modified quantitative approach to identifying extreme events in environmental records, proposing that organisms are stressed by deviations of the environment from the current level of acclimatization, rather than by the environment's absolute state. This approach facilitates an unambiguous null model for the consequences of environmental variation, identifying a unique subset of events as 'extremes'. Specifically, it allows one to examine how both the temporal extent (the acclimatization window) and type of an environmental signal affect the magnitude and timing of extreme environmental events. For example, if physiology responds to the moving average of past conditions, a longer acclimatization window generally results in greater imposed stress. If instead physiology responds to historical maxima, longer acclimatization windows reduce imposed stress, albeit perhaps at greater constitutive cost. This approach should be further informed and tested with empirical experiments addressing the history-dependent nature of acclimatization.


Assuntos
Aclimatação , Mudança Climática , Adaptação Fisiológica , Animais , Clima , Meio Ambiente , Temperatura
14.
Conserv Physiol ; 7(1): coz053, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31528348

RESUMO

Body temperature affects plants' and animals' performance, but these effects are complicated by thermal variation through time within an individual and variation through space among individuals in a population. This review and synthesis describes how the effects of thermal variation-in both time and space-can be estimated by applying a simple, nonlinear averaging scheme. The method is first applied to the temporal variation experienced by an individual, providing an estimate of the individual's average performance. The method is then applied to the scale-dependent thermal variation among individuals, which is modelled as a 1/f-noise phenomenon. For an individual, thermal variation reduces average performance, lowers the temperature of maximum performance (Topt ) and contracts the range of viable temperatures. Thermal variation among individuals similarly reduces performance and lowers Topt , but increases the viable range of average temperatures. These results must be viewed with caution, however, because they do not take into account the time-dependent interaction between body temperature and physiological plasticity. Quantifying these interactions is perhaps the largest challenge for ecological and conservation physiologists as they attempt to predict the effects of climate change.

15.
J Exp Biol ; 222(Pt 17)2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31395674

RESUMO

Intertidal communities of wave-swept rocky shores have served as a powerful model system for experiments in ecology, and mussels (the dominant competitor for space in the mid-intertidal zone) play a central role in determining community structure in this physically stressful habitat. Consequently, the ability to account for mussels' physiological responses to thermal stress affects ecologists' capacity to predict the impacts of a warming climate on this ecosystem. Here, we examined the effect of heating rate on cardiac thermal tolerance in the ribbed mussel, Mytilus californianus, comparing populations from high and low sites in the intertidal zone where emersion duration leads to different mean daily heating rates. Two temperature-related cardiac variables were examined: (1) the critical temperature (Tcrit) at which heart rate (HR) precipitously declines, and (2) flatline temperature (FLT) where HR reaches zero. Mussels were heated in air at slow, moderate and fast rates, and HR was measured via an infrared sensor affixed to the shell. Faster heating rates significantly increased Tcrit in high- but not low-zone mussels, and Tcrit was higher in high- versus low-zone mussels, especially at the fastest heating rate. By contrast, FLT did not differ between zones, and was minimally affected by heating rate. As heating rate significantly impacted high- but not low-zone mussels' cardiac thermal tolerance, realistic zone-specific heating rates must be used in laboratory tests if those tests are to provide accurate information for ecological models attempting to predict the effects of increasing temperature on intertidal communities.


Assuntos
Calefação , Mytilus/fisiologia , Termotolerância , Animais , Coração/fisiologia
16.
Eur J Immunol ; 49(11): 2083-2094, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31393597

RESUMO

Transcutaneous immunization (TCI) is a novel vaccination strategy that utilizes skin-associated lymphatic tissue to induce immune responses. Employing T-cell epitopes and the TLR7 agonist imiquimod onto intact skin mounts strong primary, but limited memory CTL responses. To overcome this limitation, we developed a novel imiquimod-containing vaccination platform (IMI-Sol) rendering superior primary CD8+ and CD4+ T-cell responses. However, it has been unclear whether IMI-Sol per se is restricted in terms of memory formation and tumor protection. In our present work, we demonstrate that the combined administration of IMI-Sol and CD40 ligation unleashes fullblown specific T-cell responses in the priming and memory phase, strongly enhancing antitumor protection in mice. Interestingly, these effects were entirely CD4+ T cell independent, bypassing the necessity of helper T cells. Moreover, blockade of CD70 in vivo abrogated the boosting effect of CD40 ligation, indicating that the adjuvant effect of CD40 in TCI is mediated via CD70 on professional APCs. Furthermore, this work highlights the so far underappreciated importance of the CD70/CD27 interaction as a promising adjuvant target in TCI. Summing up, we demonstrate that the novel formulation IMI-Sol represents a powerful vaccination platform when applied in combination with sufficient adjuvant thereby overcoming current limitations of TCI.


Assuntos
Ligante CD27/imunologia , Ligante de CD40/administração & dosagem , Imiquimode/administração & dosagem , Melanoma Experimental/terapia , Neoplasias Cutâneas/terapia , Linfócitos T Citotóxicos/efeitos dos fármacos , Administração Cutânea , Aloenxertos , Animais , Ligante CD27/genética , Citotoxicidade Imunológica/efeitos dos fármacos , Expressão Gênica , Rejeição de Enxerto , Imunização/métodos , Memória Imunológica/efeitos dos fármacos , Imunoterapia/métodos , Melanoma Experimental/genética , Melanoma Experimental/imunologia , Melanoma Experimental/patologia , Glicoproteínas de Membrana/agonistas , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Ovalbumina/administração & dosagem , Pele/efeitos dos fármacos , Pele/imunologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/patologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/patologia , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/patologia , Receptor 7 Toll-Like/agonistas , Receptor 7 Toll-Like/genética , Receptor 7 Toll-Like/imunologia
17.
Integr Zool ; 13(4): 392-410, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29316299

RESUMO

As Earth's climate warms, plants and animals are likely to encounter increased frequency and severity of extreme thermal events, and the ensuing destruction is likely to play an important role in structuring ecological communities. However, accurate prediction of the population-scale consequences of extreme thermal events requires detailed knowledge of the small-scale interaction between individual organisms and their thermal environment. In this study I propose a simple model that allows one to explore how individual-to-individual variation in body temperature and thermal physiology determines what fraction of a population will be killed by an extreme thermal event. The model takes into account the possibility that each individual plant or animal can respond to an event by adjusting its thermal tolerance in proportion to the stress it encounters. When thermal stress is relatively mild, the model shows that a graded physiological response of this sort leads to increased survivorship. However, the model predicts that in more severe events a proportional induced defense can actually reduce survivorship, a counterintuitive possibility that is not predicted by standard theory. The model can easily be tailored to different species and thermal environments to provide an estimate of when, where and how physiology can buffer the effects of climate warming.


Assuntos
Aclimatação/fisiologia , Regulação da Temperatura Corporal/fisiologia , Estresse Fisiológico/fisiologia , Temperatura , Animais , Modelos Teóricos , Fenômenos Fisiológicos Vegetais , Plantas , Análise de Sobrevida
18.
J Dermatol Sci ; 87(3): 300-306, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28666747

RESUMO

BACKGROUND: The epidermal application of the Toll Like Receptor 7 agonist imiquimod and a T-cell peptide epitope (transcutaneous immunization, TCI) mediates systemic peptide-specific cytotoxic T-cell (CTL) responses and leads to tumor protection in a prophylactic tumor setting. However, it does not accomplish memory formation or permanent defiance of tumors in a therapeutic set-up. As a distinct immunologic approach, CTLA-4 blockade augments systemic immune responses and has shown long-lasting effects in preclinical experiments as well as in clinical trials. OBJECTIVE: The study investigates the vaccination capacity of TCI in combination with the checkpoint inhibitor CTLA-4 in matters of primary response, memory formation and tumor protection and characterizes the role of regulatory T cells (Tregs). METHODS: After performing TCI with IMI-Sol (containing 5% Imiquimod) and the model epitope SIINFEKL, 6-8 week old C57BL/6 mice received anti-CTLA-4 antibody either s.c or i.p. The CTL responses and frequency of peptide specific CD8+ T-cells were then evaluated on day 8. To determine anti-tumor effects, a therapeutic tumor challenge with B16 OVA melanoma was performed. RESULTS: The combination of s.c. anti-CTLA-4 antibody and TCI leads to an enhanced systemic cytotoxic response, to memory formation and allows significantly improved survival in a tumor setting with B16 OVA melanoma. Towards the mechanism, we show that in this vaccination protocol the CTLA-4 antibody acts mainly Treg-independent. CONCLUSION: We demonstrate that the combination of TCI with IMI-Sol and anti-CTLA-4 can confer potent immune responses and tumor-protection. These results might contribute to the development of advanced vaccination approaches targeting tumors or persistent infectious diseases.


Assuntos
Adjuvantes Imunológicos/farmacologia , Antineoplásicos Imunológicos/farmacologia , Antígeno CTLA-4/antagonistas & inibidores , Melanoma Experimental/terapia , Neoplasias Cutâneas/terapia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Reguladores/imunologia , Adjuvantes Imunológicos/uso terapêutico , Aminoquinolinas/farmacologia , Aminoquinolinas/uso terapêutico , Animais , Antineoplásicos Imunológicos/uso terapêutico , Antígeno CTLA-4/imunologia , Sinergismo Farmacológico , Citometria de Fluxo , Humanos , Imiquimode , Memória Imunológica/efeitos dos fármacos , Imunoterapia/métodos , Melanoma Experimental/imunologia , Melanoma Experimental/mortalidade , Glicoproteínas de Membrana/antagonistas & inibidores , Camundongos , Camundongos Endogâmicos C57BL , Ovalbumina/farmacologia , Ovalbumina/uso terapêutico , Fragmentos de Peptídeos/farmacologia , Fragmentos de Peptídeos/uso terapêutico , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/mortalidade , Linfócitos T Citotóxicos/metabolismo , Linfócitos T Reguladores/metabolismo , Receptor 7 Toll-Like/antagonistas & inibidores , Ensaios Antitumorais Modelo de Xenoenxerto
19.
J Dermatol Sci ; 87(3): 252-259, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28655469

RESUMO

BACKGROUND: Transcutaneous immunization (TCI) is a novel vaccination strategy utilizing the skin associated lymphatic tissue to induce immune responses. TCI using a cytotoxic T lymphocyte (CTL) epitope and the Toll-like receptor 7 (TLR7) agonist imiquimod mounts strong CTL responses by activation and maturation of skin-derived dendritic cells (DCs) and their migration to lymph nodes. However, TCI based on the commercial formulation Aldara only induces transient CTL responses that needs further improvement for the induction of durable therapeutic immune responses. OBJECTIVE: Therefore we aimed to develop a novel imiquimod solid nanoemulsion (IMI-Sol) for TCI with superior vaccination properties suited to induce high quality T cell responses for enhanced protection against infections. METHODS: TCI was performed by applying a MHC class I or II restricted epitope along with IMI-Sol or Aldara (each containing 5% Imiquimod) on the shaved dorsum of C57BL/6, IL-1R, Myd88, Tlr7 or Ccr7 deficient mice. T cell responses as well as DC migration upon TCI were subsequently analyzed by flow cytometry. To determine in vivo efficacy of TCI induced immune responses, CTL responses and frequency of peptide specific T cells were evaluated on day 8 or 35 post vaccination and protection in a lymphocytic choriomeningitis virus (LCMV) infection model was assessed. RESULTS: TCI with the imiquimod formulation IMI-Sol displayed equal skin penetration of imiquimod compared to Aldara, but elicited superior CD8+ as well as CD4+ T cell responses. The induction of T-cell responses induced by IMI-Sol TCI was dependent on the TLR7/MyD88 pathway and independent of IL-1R. IMI-Sol TCI activated skin-derived DCs in skin-draining lymph nodes more efficiently compared to Aldara leading to enhanced protection in a LCMV infection model. CONCLUSION: Our data demonstrate that IMI-Sol TCI can overcome current limitations of previous imiquimod based TCI approaches opening new perspectives for transcutaneous vaccination strategies and allowing the use of this enhanced cutaneous drug-delivery system to be tailored for the improved prevention and treatment of infectious diseases and cancers.


Assuntos
Aminoquinolinas/uso terapêutico , Células de Langerhans/efeitos dos fármacos , Coriomeningite Linfocítica/prevenção & controle , Neoplasias Cutâneas/prevenção & controle , Linfócitos T Citotóxicos/efeitos dos fármacos , Administração Cutânea , Animais , Movimento Celular , Modelos Animais de Doenças , Emulsões , Epitopos/imunologia , Citometria de Fluxo , Humanos , Imiquimode , Células de Langerhans/imunologia , Coriomeningite Linfocítica/imunologia , Coriomeningite Linfocítica/virologia , Vírus da Coriomeningite Linfocítica/imunologia , Complexo Principal de Histocompatibilidade/imunologia , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/metabolismo , Transdução de Sinais/imunologia , Pele/citologia , Pele/efeitos dos fármacos , Pele/imunologia , Neoplasias Cutâneas/imunologia , Linfócitos T Citotóxicos/imunologia , Receptor 7 Toll-Like/genética , Receptor 7 Toll-Like/metabolismo , Vacinação/métodos
20.
Sci Rep ; 7(1): 2249, 2017 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-28533550

RESUMO

Reef coral assemblages are highly dynamic and subject to repeated disturbances, which are predicted to increase in response to climate change. Consequently there is an urgent need to improve our understanding of the mechanisms underlying different recovery scenarios. Recent work has demonstrated that reef structural complexity can facilitate coral recovery, but the mechanism remains unclear. Similarly, experiments suggest that coral larvae can distinguish between the water from healthy and degraded reefs, however, whether or not they can use these cues to navigate to healthy reefs is an open question. Here, we use a meta-analytic approach to document that coral larval swimming speeds are orders of magnitude lower than measurements of water flow both on and off reefs. Therefore, the ability of coral larvae to navigate to reefs while in the open-ocean, or to settlement sites while on reefs is extremely limited. We then show experimentally that turbulence generated by fine scale structure is required to deliver larvae to the substratum even in conditions mimicking calm back-reef flow environments. We conclude that structural complexity at a number of scales assists coral recovery by facilitating both the delivery of coral larvae to the substratum and settlement.


Assuntos
Antozoários/fisiologia , Recifes de Corais , Larva , Animais , Comportamento Animal , Ecossistema , Natação , Movimentos da Água
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