Adaptations and plastic phenotypic responses of marine animals to the environmental challenges of the high intertidal zone

The high intertidal zone is home to an incredible variety of marine animals, as it offers an escape from low intertidal/subtidal predation and competition, among other advantages. However, this area of the shore also comes with many tide-driven and emersion-associated environmental stressors, such as desiccation, high temperatures and freezing stress, hypoxia, salinity fluctuations, nitrogenous waste accumulation, ultraviolet (UV) radiation, wave and ice disturbance, and hydrogen sulphide (H2S) toxicity. This review explores the diversity of evolutionary adaptations and plastic phenotypic responses that high intertidal animals use to cope with these challenges. Examples are provided of behavioural, morphological, physiological and biochemical adaptations/responses, along with some of the underlying molecular mechanisms that have been elucidated to date. Adaptations of many different worms, anemones, molluscs, crustaceans and fishes are highlighted. Many adaptations and mechanisms of plasticity are universal among animal phyla, and some are multifunctional (serve more than one function) or provide tolerance to multiple stressors (i.e., ‘cross-tolerance’). High intertidal animals have received considerable attention by scientists, given their accessibility and that they can provide valuable insights in the transition from a marine to a terrestrial lifestyle. Nevertheless, further research is needed to understand the adaptations/responses of these animals more thoroughly, and the future holds great promise for accomplishing this with recent advances in epigenetics, transcriptomics, protein biochemistry and other molecular tools.

Nurses’ eating habits in Lebanon during the economic and health crises: a cross-sectional study

Background Nurses face multiple stressors that can influence their lifestyle, thus affecting their health status. Scarce are the scientific data on the nutritional status of nurses, especially during health crises. The aim of this study was to assess the impact of the COVID-19 pandemic on the eating habits of hospital nurses in the context of an exceptional economic situation in Lebanon. Methods A cross-sectional study was conducted using a web-based questionnaire, targeting a non-random sampling of frontline nurses using the snowball technique. Descriptive and bivariate analyses were carried out. The population of the study included all registered nurses working in the Lebanese hospitals. A total of 533 nurses completed the questionnaire; 500 surveys were selected after excluding the ones presenting conditions that may affect their eating behavior. Results The majority of the respondents were women (78.6%) with a mean age of 33 years [18-60] [SD,7.44 years]. Most of them (57.6%) had a crowding index ≥1. The consumption of different food groups decreased during these crises. There was a significant correlation between stress and deterioration of healthy food consumption, which provides beneficial nutrients and minimizes potentially harmful elements, especially for meat (OR 2.388, CI 1.463 to 3.898, P < 0.001). The decrease in monthly income showed a real impact on the consumption of healthy food such as meat (OR 2.181, CI 1.504 to 3.161, P < 001), fruits (OR 1.930, CI 1.289 to 2.888, P = 0.001), and milk and dairy products (OR 1.544, CI 1.039 to 2.295, P = 0.031). Conclusions The pandemic and in particular the economic crisis has changed the consumption of healthy food among hospital nurses in Lebanon. Similar research and support may be extended to include other frontline health care workers.

A honey bee symbiont buffers larvae against nutritional stress through lysine supplementation

Honey bees, the worlds most significant agricultural pollinator, have suffered dramatic losses in the last few decades. These losses are largely due to the synergistic effects of multiple stressors, the most pervasive of which is limited nutrition. The effects of poor nutrition are most damaging in the developing larvae of honey bees, who mature into workers unable to meet the needs of their colony. It is therefore essential that we better understand the nutritional landscape experienced by honey bee larvae. In this study, we characterize the metabolic capabilities of a honey bee larvae-associated bacterium, Bombella apis (formerly Parasaccharibacter apium), and its effects on the nutritional resilience of larvae. We found that B. apis is the only bacterium associated with larvae that can withstand the antimicrobial larval diet. Further, we found that B. apis can synthesize all essential amino acids and significantly alters the amino acid content of synthetic larval diet, largely by increasing the essential amino acid lysine. Analyses of gene gain/loss across the phylogeny suggest that two distinct cationic amino acid transporters were gained by B. apis ancestors, and the transporter LysE is conserved across all sequenced strains of B. apis. This result suggests that amino acid export is a key feature conserved within the Bombella clade. Finally, we tested the impact of B. apis on developing honey bee larvae subjected to nutritional stress and found that larvae supplemented with B. apis are bolstered against mass reduction despite limited nutrition. Together, these data suggest an important role of B. apis as a nutritional mutualist of honey bee larvae.

Commonalities in the Features of Cancer and Chronic Fatigue Syndrome (CFS): Evidence for Stress-Induced Phenotype Instability?

Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) and Cancer-Related Fatigue (CRF) are syndromes with considerable overlap with respect to symptoms. There have been many studies that have compared the two conditions, and some of this research suggests that the etiologies of the conditions are linked in some cases. In this narrative review, CFS/ME and cancer are introduced, along with their known and putative mechanistic connections to multiple stressors including ionizing radiation. Next, we summarize findings from the literature that suggest the involvement of HPA-axis dysfunction, the serotonergic system, cytokines and inflammation, metabolic insufficiency and mitochondrial dysfunction, and genetic changes in CRF and CFS/ME. We further suspect that the manifestation of fatigue in both diseases and its causes could indicate that CRF and CFS/ME lie on a continuum of potential biological effects which occur in response to stress. The response to this stress likely varies depending on predisposing factors such as genetic background. Finally, future research ideas are suggested with a focus on determining if common biomarkers exist in CFS/ME patients and those afflicted with CRF. Both CFS/ME and CRF are relatively heterogenous syndromes, however, it is our hope that this review assists in future research attempting to elucidate the commonalities between CRF and CFS/ME.

Analyzing the relationship between distracted driving and eye movement using multimodal data collected during car driving

Human error is the leading cause of traffic accidents and originates from the distraction caused by various factors, such as the driver's physical condition and mental state. One of the significant factors causing driver distraction is the presence of stress. In a previous study, multiple stressors were used to examine distraction while driving. Multiple stressors were given to the driver and the corresponding driver biometric data were obtained, and a multimodal dataset was published thereafter. In this study, we reiterate the results of existing studies and investigated the relationship between gaze variability while driving and stressor intervention, which has not yet been examined. We also examined whether biometric and vehicle information can estimate the presence or absence of secondary tasks during driving.

Asymmetry drives the cumulative impacts of multiple stressors on freshwater ecosystems under a warming climate

Climate warming is an important stressor in freshwater ecosystems, yet its interactive effects with other environmental changes are poorly understood. We address this challenge by testing the ability of three contrasting null models to predict the joint impacts of warming and a second stressor using a new database of 296 experimental combinations. Despite concerns that stressors will interact to cause synergisms, we found that net impacts were best explained by the effect of the worst stressor (the dominance null model). When this stressor’s impact was at least 50% greater than that of the second, the dominance model was most accurate in 62% of responses. Prediction accuracy depended on the identity of the stressors and declined at higher levels of biological organisation. Together these findings suggest we can often effectively forecast impacts of multiple stressors by focusing on the degree of asymmetry that exists among their independent impacts.

Stratified microbial communities are highly sensitive towards multiple combined global change factors, revealing antagonistic and synergistic effects

Microbial communities in many ecosystems are facing a broad range of global change scenarios, resulting in microbial changes and possibly regime shifts with unknown ecological consequences. While the influence of single stressors is already described in numerous studies, the effects of multiple stressors working simultaneously are still poorly understood. In this study, we used 240 highly replicable oxic/anoxic aquatic lab micro-ecosystems to understand the influence of four stressors (fertilizer, glyphosate, metal pollution, antibiotics) in all possible combinations at three different temperatures (20 °C, 24 °C, and 28 °C) to shed light into consequences of multiple stressors on different levels of organization, ranging from species abundance to community and ecosystem parameters. Our data reveal that (i) combination of specific stressors can change the biological consequence and direction compared to single stressors in all levels of organisation (ii), effects of stressor combinations are modified by temperature, and (iii) that the number of stressors applied also lead to significant changes. In sum, our study confirmed the need of investigating multiple stressors working simultaneously across different ecological levels of organisation.