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Supplementary Table S3 - Article: Transcriptome Analysis Provides Novel Insights into Salinity Stress Response in two Egyptian Rice Varieties with Different Tolerance Levels

Table S3. Repository data for the global analysis produced for cv Giza 178.  A, Up regulated genes observed when comparing salt stressed plants vs unstressed controls.  B, Down regulated genes in Giza 178 observed when comparing salt stressed plants vs unstressed controls. C, Gene Ontology enrichment analysis (GOEA) results for Giza 178 up regulated genes.    D, GOEA results for Giza 178 down regulated genes.

Data to: The importance of ecotype diversity on duckweed growth with and without salt stress

To test if ecotype diversity could increase resistance to stressful environments, I used seven Lemna minor populations and measured their growth rates with and without moderate salt stress across an ecotype diversity gradient. The L. minor populations were grown over five months in 92 experimental mesocosms in a glasshouse, either in ecotype monocultures or in polyculture with either one or three conspecific ecotypes (23 unique compositions). After growing the duckweed in unperturbed conditions (phase 1), the cultures were subjected to moderate salt stress (50mM NaCl) for several weeks (phase 2). The experiment was conducted in the presence of the natural epimicrobial community associated with the different ecotypes. In phase 2, a subset of these algae added an unintentional second stressor to the experiment.

opencc-zeroMar 2022View details →

The importance of facilitation on community assembly disappears under severe drought stress

Despite the recognition of positive interactions as an important driver of species coexistence and community structure, the underlying mechanism of how facilitation affects assembly processes along stress gradients is poorly explored. Understanding the responses of functional diversity to benefactor species at the extreme end of the stress gradient could provide valuable insight about facilitation-involved assembly mechanisms and contribute to the predictions of species coexistence under climate change. In the drought-stressed community in the Badain-Jaran Desert, the responses of the local community to the nurse shrub species Calligonum mongolicum Turcz. were evaluated using hierarchical Bayesian models. For the 3-year experiment, summer rainfall in each year formed a natural gradient of drought stress. To evaluate the shrub's effects on the assembly process along that gradient, individual samples were collected in pairwise under-shrub and open habitats, and four traits related to stress tolerance and resource acquisition were measured simultaneously. Under moderate drought stress, we observed shifting community-weighted means, broadening ranges and reducing overlaps of functional traits under shrubs. These effects were partly driven by a distinct microenvironment created by shrub plants, in particular the improvement and heterogeneity of soil moisture conditions. However, this influence on trait distributions was strongly dependent on the environmental context, and generally disappeared as drought stress shifted toward its driest end, almost in line with the decreased positive interaction assessed by plant density and species diversity. This study focused on water-limited community that lies at the driest end of drought gradient and confirmed that facilitation can drive the assembly process through both environmental filtering and niche differentiation. More importantly, these assembly mechanisms are proven to become less efficient under extreme drought stress, which may suggest the occasionally disappearing role of benefactor plants on community assembly and an increasing risk of biodiversity loss in the context of climate change.

opencc-zeroMar 2022View details →

Abiotic stress and biotic factors mediate range dynamics on opposing edges

Aim: In the face of global change, understanding causes of range limits is one of the most pressing needs in biogeography and ecology. A prevailing hypothesis is that abiotic stress forms cold (upper latitude/altitude) limits whereas biotic interactions create warm (lower) limits. A new framework – Interactive Range-Limit Theory (iRLT) – asserts that positive biotic factors such as food availability can ameliorate abiotic stress along cold edges, whereas abiotic stress can have a positive effect and mediate biotic interactions (e.g., competition) along warm limits. Location: Northeastern US Taxon: Carnivora Methods: We evaluated two hypotheses of iRLT using occupancy and structural equation modeling (SEM) frameworks based on data collected over a six-year period (2014–2019) of six carnivore species across a broad latitudinal (42.8–45.3°N) and altitudinal (3–1451 m) gradient. Results: We found that snow directly limits populations, but prey or habitat availability can influence range dynamics along cold edges. For example, bobcats (Lynx rufus) and coyotes (Canis latrans) were limited by deep snow and long winters, but the availability of prey had a strong positive effect. Conversely, snow had a strong positive effect on the warm limits of Canada lynx (Lynx canadensis), countering the negative effect of competition with the phylogenetically-similar bobcat and with coyotes, highlighting how climate mediates competition between species. Main conclusions: We used an integrated dataset that included competitors and prey species collected at the same spatial and temporal scale. As such, this design, along with a causal modeling framework (SEM), allowed us to evaluate community-wide hypotheses at macroecological scales and identify coarse-scale drivers of species' range limits. Our study supports iRLT and underscores the need to consider direct and indirect mechanisms for studying range dynamics and species' responses to global change.

Future Heat Stress Indicators for Johannesburg and Ekurhuleni

This dataset is part of the scientific paper: Souverijns, N., De Ridder, K., Veldeman, N., Lefebre, F., Kusambiza-Kiingi, F., Memela, W., Jones, N.K.W., 2022. Urban heat in Johannesburg and Ekurhuleni, South Africa: A meter-scale assessment and vulnerability analysis. Urban Climate, 46, 101331. <a href="https://doi.org/10.1016/j.uclim.2022.101331">https://doi.org/10.1016/j.uclim.2022.101331</a> Heat stress indicators for present and future climates for the cities of Johannesburg and Ekurhuleni (South Africa).at 30m spatial resolution calculated with UrbClim (De Ridder et al., 2015) for the following scenarios: - 2001-2020: present time (ERA5 input data) - 2021-2040 RCP4.5 (CMIP5 ensemble) - 2021-2040 RCP8.5 (CMIP5 ensemble) - 2041-2060 RCP4.5 (CMIP5 ensemble) - 2041-2060 RCP8.5 (CMIP5 ensemble) For each of the 23 indicators, an overview image is available at high resolution. Furthermore, georeferenced GeoTiffs are available to visualize & analyse the indicators on the users preferred system. The indicators are available in EPSG4326/WGS84. A description of each indicator is given: - Cooling degree hours: Annual number of hours during which the temperatures rises over 25°C, multiplied by the number of degrees the temperature rises above 25°C. This is an international standard to estimate the energy demand for air conditioning use. - CSDI: Cold spell duration index. Annual number of days with at least six consecutive days when the night temperature < 10th percentile - Heatwave days: Number of heatwave days per year calculated following the definition of the South African Weather Service. If the maximum temperature at a particular town is expected to meet or exceed 5 degrees C above the average maximum temperature of “the hottest month” for that particular place (this is 32°C for Johannesburg & Ekurhuleni), as well as persisting in that mode for 3 days or more (https://www.weathersa.co.za/home/weatherques) - T2M_daily_mean_max: Average daily maximum temperature - T2M_daily_mean_max_topography: Daytime Urban Heat Island corrected for topography - T2M_daily_mean_min: Average daily minimum temperature - T2M_daily_mean_min_topography: Nighttime Urban Heat Island corrected for topography - T2M_dayover25: Annual number of days attaining a maximum temperature > 25°C - T2M_dayover25_duetourban: Annual number of days attaining a maximum temperature > 25°C that are caused by urban canopy - T2M_dayover30: Annual number of days attaining a maximum temperature > 30°C - T2M_dayover30_duetourban: Annual number of days attaining a maximum temperature > 30°C that are caused by urban canopy - T2M_max: Absolute maximum temperature - T2M_mean: Absolute average temperature - T2M_min: Absolute minimum temperature - T2M_nightover20: Number of nights attaining a minimum temperature not dropping below 20°C - T2M_nightover25: Number of nights attaining a minimum temperature not dropping below 25°C - TN10P: Annual number of days when the night temperature < 10th percentile - TN90P: Annual number of days when the night temperature > 90th percentile - TN_max: Annual minimum nighttime warmest temperature - TX10P: Annual number of days when the day temperature < 10th percentile - TX90P: Annual number of days when the day temperature > 90th percentile - TX_min: Annual maximum daytime coolest temperature - WSDI: Warm Spell Duration Index. Annual number of days with at least six consecutive days when daytime temperatues > 90th percentile

Role of Alkylhydroperoxidase Rv2159c in the Oxidative Stress Response and Virulence of Mycobacterium tuberculosis

Mycobacterium tuberculosis, which causes tuberculosis, is one of the leading infectious agents worldwide with a high rate of mortality. Following aerosol inhalation, M. tuberculosis primarily infects the alveolar macrophages, which results in a host immune response that gradually activates various antimicrobial mechanisms, including the production of reactive oxygen species (ROS), within the phagocytes to neutralize the bacteria. OxyR is the master regulator of oxidative stress response in several bacterial species. However, due to the absence of a functional oxyR locus in M. tuberculosis, the peroxidase stress is controlled by alkylhydroperoxidases. M. tuberculosis expresses alkylhydroperoxide reductase to counteract the toxic effects of ROS. In the current study, we report the functional characterization of an ortholgue of alkylhydroperoxidase family member, Rv2159c, a conserved protein with putative peroxidase activity, during stress response and virulence of M. tuberculosis. We generated a gene knockout mutant of M. tuberculosis Rv2159c (MtbΔ2159) by specialized transduction. The MtbΔ2159 was sensitive to oxidative stress and exposure to toxic transition metals. In a human monocyte (THP-1) cell infection model, MtbΔ2159 showed reduced intracellular survival and increased expression of pro-inflammatory molecules, includingIL-1β, IP-10 and MIP-1α, compared to the wild type M. tuberculosis and Rv2159c-complemented MtbΔ2159 strains. Similarly, in a guinea pig model of pulmonary infection, MtbΔ2159 displayed growth attenuation in the lungs, compared to the wild type M. tuberculosis and Rv2159c-complemented MtbΔ2159 strains. Our study suggests that Rv2159c has a significant role in maintaining the cellular homeostasis during stress and virulence of M. tuberculosis.

Processed and additional data for our publication titled "Endoplasmic reticulum stress activates human IRE1α through reversible assembly of inactive dimers into small oligomers"

This is an updated version of our original data archive (which can be found under the doi 10.5281/zenodo.5513025) that reflects changes we've made to the manuscript over the course of the review process and incorporates the new data we've collected since the time of the initial bioRxiv submission. This data archive contains all raw data EXCEPT for single-particle microscopy movies (which are deposited separately due to their size) for our paper titled "Endoplasmic reticulum stress activates human IRE1a through reversible assembly of inactive dimers into small oligomers". These raw data are stored in "non_SPT_data_final_v2.zip". Additionally, full plasmid sequences for all plasmids  used in this paper are stored in GenBank format in the file "plasmid_sequences_v2.zip". Finally, this repository contains processed single-particle movies in the form of dual-color tracks from the TrackMate ImageJ plugin in XML format (file: "SPT_processed_data_and_settings_final_v2.zip"). The processed XML tracks are organized in the same way as the raw data files in the separate repository. They are sorted into subfolders by date of acquisition first, followed by experimental conditions. To recreate the figures from the paper, follow instructions in the README.md file included with the source code repository and use the JSON settings files saved here under "analysis_settings".

Astaxanthin from Haematococcus pluvialis prevents high-fat diet-induced hepatic steatosis and oxidative stress in mice by gut-liver axis modulating properties

Scope: Evidence is mounting that astaxanthin (ATX), a xanthophyll carotenoid, used as a nutritional supplement to prevent chronic metabolic diseases. The present study aims to identify the potential function of ATX supplementation in preventing steatohepatitis and hepatic oxidative stress in diet-induced obese mice. Methods and Results: In this study, ATX as dose of 0.25%, 0.5% and 0.75% have orally administered to mice along with a high-fat diet (HFD) to investigate the role of ATX in regulating liver lipid metabolism and gut microbiota. The study showed that ATX dose-dependently reduces body weight, lipid droplet formation, hepatic triglycerides and ameliorated hepatic steatosis and oxidative stress. 0.75% ATX altered the levels of 34 lipid metabolites related to hepatic cholesterol and fatty acid metabolism which might be associated with downregulation of lipogenesis-related genes and upregulation of bile acid biosynthesis-related genes. The result also revealed that ATX alleviates HFD-induced gut microbiota dysbiosis by significantly inhibiting the growth of obesity-related Parabacteroides and Desulfovibrio while promoting the growth of Allobaculum and Akkermansia. Conclusion: The study results suggested that dietary ATX may prevent the development of hepatic steatosis and oxidative stress with the risk of metabolic disease by gut-liver axis modulating properties.

opencc-by-4.0Jun 2021View details →

Pre and post- processing files and scripts for the paper 'The effect of local shear stress on glacier sliding'

The folder contains: <ul> <li>A set of .F90 to be compiled in order to run the simulations with Elmer Ice</li> <li>A python script called newmodel_2a.py for generating the complete analytical model shown in the appendix</li> <li>scripts for post-processing the results. The paths have to be edited. They read the .dat files, extract the main variables: u_b, \tau_b, N and compute C to produce the friction law plots. It also computes the ratio Af/As and produces the respective plots</li> <li>A compressed folder called results with the outputs of the main results. They include the results (.dat file) and the .sif files to run the simulations with FEM software Elmer/Ice. Their names are already included in a small subroutine in the postprocessing script</li> <li>A compressed folder called comparison with the outputs of the comparison between models. They include the results (.dat file) and the .sif files to run the simulations with FEM software Elmer/Ice, as well as the complete solution for the new models (in order to extract \tau_f for the sandpaper model we need the complete flow solution).</li> </ul>

opencc-by-4.0Nov 2021View details →

Smart Battery Management System for Electric Vehicles: Selflearning Algorithms for Simultaneous State and Parameter Estimation, and Stress Detection

The project proposes to develop parameter-varying SOH-coupled models for lithium-ion battery and self-learning algorithms to learn the model for simultaneous state and parameter estimation and fault detection. The traditional battery models use constant parameters, limiting their accuracy for predicting the state of the charge and health over the complete life-cycle. In practice, the battery parameters vary with the change in the state of charge and state of health. SOH-coupled models can be used to estimate the state of charge and health accurately. Further, obtaining the model parameters is also a challenging task for designing filters or observers for state estimation. A self-learning algorithm can eliminate the requirement of the model parameters. In this project, three SOH-coupled models are proposed and validated experimentally. The models are also used to design extended Kalman filters (EKF) for the state of charge, state of health, core and surface temperature, and internal resistance estimation. The results showed that the SOHcoupled models are more effective when compared to the uncoupled models in the literature. Further, it was found that EKFs based state estimation errors were within 1%. The self-learning algorithm using a two-layer neural network showed the ability to learn the models in real-time. However, the state estimation errors are higher for the self-learning scheme compared to the EKF based approaches. This is due to the limited measurement and online training schemes utilized to train neural networks. This requires further investigation in hyper-parameter tuning for implementation. Finally, a model-based fault detection scheme was proposed to detect internal thermal fault at its onset. The SOHcoupled model is reformulated to incorporate the internal resistance as a state. The EKF is used as a fault detection observer. The proposed fault detection scheme is validated using numerical simulation. It was observed that the fault detection scheme with SOH coupled electro-thermal-aging model could effectively detect a thermal fault at its incipient state.

Advance social information allows red crossbills (Loxia curvirostra) to better conserve body mass and intestinal mass during food stress

Animals prepare for fluctuations in resources through advance storage of energy, planned reduction in energy costs or by moving elsewhere. Unpredictable fluctuations in food, however, may be particularly challenging if animals cannot avoid negative impacts on body condition. Social information may help animals to cope with unpredictable resources if cues from individuals with low foraging success give advance warning about deteriorating conditions. This study investigates the impact of social information on behavior and physiology of food-restricted captive red crossbills (Loxia curvirostra). Birds were restricted to two short feeding periods per day to simulate a decline in resources and were given social information from food-restricted neighbors either before (i.e., predictive) or during (i.e., parallel) the food restriction period. Focal birds better conserved body mass during food restriction if social information was predictive of the decline in resources. Crossbills with predictive information ate more food, had larger intestinal mass and better conserved pectoral muscle size at the end of the restriction period compared to those with parallel social information. These data suggest that birds can use social information to alter behavioral and physiological responses during food shortage in ways that may confer an adaptive advantage for survival.

Data from: Breeding heat tolerant orchardgrass germplasm for summer persistence in high temperature stress environments of the southeastern United States

This is digital research data corresponding to a published manuscript, Breeding heat tolerant orchardgrass germplasm for summer persistence in high temperature stress environments of the southeastern United States, in Crop Science, Volume 61, p. 1915 - 1925. Orchardgrass (Dactylis glomerata L.) could serve as a cool-season perennial in southeastern production systems, but often does not behave as a true perennial under high temperature stress conditions of the region. This work sought to develop heat-tolerant orchardgrass germplasm through recurrent phenotypic selection (RPS) that would both reduce secondary seed dormancy caused by high soil temperatures and improve stand persistence over summer months. Selection was conducted in a growth chamber 40/30 °C (12/12 h, light/darkness), with germinated seedlings subjected to an additional 2–3 weeks of 40/30 °C conditions. The base germplasm (Cycle 0) and selected individuals (Cycles 1–3) were transplanted into the field, then harvested for seed. Forty-degree germination tests compared mean cumulative germination, velocity of germination within 8 days (VOG8), and realized heritability. Stand persistencewas assessed 1 year after transplanting.

opencc-by-4.0Apr 2022View details →

Data accompanying "Saildrone direct covariance wind stress in various wind and current regimes of the tropical Pacific"

Data used for creating figures in the draft article "Saildrone direct covariance wind stress in various wind and current regimes of the tropical Pacific". This includes: <ul> <li>1-minute average fields as broadcast in real time by Saildrone;</li> <li>10-minute average direct covariance fluxes (calculated by Jack Reeves Eyre);</li> <li>10-minute average bulk fluxes (calculated by Dongxiao Zhang using the COARE 3.5 algorithm).</li> </ul> Code used to calculate the direct covariance fluxes, and to create the plots, is in a Github repository (https://github.com/NOAA-PMEL/SaildroneCovarianceFlux). The repository is also archived on Zenodo (https://doi.org/10.5281/zenodo.6484795). The data are archived in a directory structure that should work with the code - only a simple edit of "src/config.py" should be required.    Version history: <ul> <li>v0.1.0 -- submission to PMEL internal review (goes with code v0.1.0, https://doi.org/10.5281/zenodo.6484796).</li> </ul>

Network analysis reveals that acute stress exacerbates gene regulatory responses of the gill to seawater in Atlantic salmon

The transition from freshwater to seawater represents a physiological challenge for Atlantic salmon smolts preparing for downstream migration. Stressors occurring during downstream migration to the ocean impair the ability of smolts to maintain osmotic/ionic homeostasis in seawater. The molecular mechanisms underlying this interaction are not fully understood, especially at the organ level. We combined RNA-Seq with measures of whole-animal homeostasis to examine gene expression dynamics in the gills of smolts associated with impaired seawater tolerance after an aquaculture-related stressor. Smolts were given a 24 h seawater tolerance test before and after exposure to an acute handling/confinement stress. RNA-Seq followed by differential expression and weighted gene correlation network analysis (WGCNA) was used to quantify the transcriptional response of the gill to handling/confinement stress, seawater and their interaction. Exposure to acute stress was associated with a general stress response and impaired osmotic/ionic homeostasis in seawater. We identified gene networks in the gill exhibiting response to acute stress alone, seawater alone, and others exhibiting combined effects of both stress and seawater. Our findings indicate that acute handling/ confinement stress increases the intensity of seawater-related gene expression and suggest that increased investment in mechanisms related to ion transport may be part of a compensatory response to impaired seawater tolerance in smolts.

Supplementary tables for Honey Bee symbiont buffers larvae against nutritional stress and supplements lysine

Honey bees have suffered dramatic losses in recent years, largely due to multiple stressors underpinned by poor nutrition. Nutritional stress especially harms larvae, who mature into workers unable to meet the needs of their colony. 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 supplying the essential amino acid lysine. Analyses of gene gain/loss across the phylogeny suggest that four amino acid transporters were gained in recent B. apis ancestors. In addition, the transporter LysE is conserved across all sequenced strains of B. apis. 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 a novel role of B. apis as a nutritional mutualist of honey bee larvae.

opencc-zeroMay 2022View details →

Stress axis programming generates long-term effects on cognitive abilities in a cooperative breeder

The ability to flexibly adjust behaviour to social and non-social challenges is important for successfully navigating variable environments. Social competence, i.e., adaptive behavioural flexibility in the social domain, allows individuals to optimize their expression of social behaviour. Behavioural flexibility outside the social domain aids in coping with ecological challenges. However, it is unknown if social and non-social behavioural flexibility share common underlying cognitive mechanisms. Support for such shared mechanism would be provided if the same neural mechanisms in the brain affected social and non-social behavioural flexibility similarly. We used individuals of the cooperatively-breeding fish Neolamprologus pulcher that had undergone early-life programming of the hypothalamic-pituitary-interrenal (HPI) axis by exposure to (i) cortisol, (ii) the glucocorticoid-receptor antagonist mifepristone or (iii) control treatments, and where effects of stress-axis programming on social flexibility occurred. One year after the treatments, adults learned a colour-discrimination task, and subsequently, a reversal-learning task testing for behavioural flexibility. Early-life mifepristone treatment only marginally affected learning performance, whereas cortisol treatment significantly reduced behavioural flexibility. Thus, early-life cortisol treatment reduced both social and non-social behavioural flexibility, suggesting a shared cognitive basis of behavioural flexibility. Further our findings imply that early-life stress programming affects the ability of organisms to flexibly cope with environmental stressors.

opencc-zeroMay 2022View details →

Image dataset: Applicability of hyperspectral imaging during salinity stress in rice for tracking Na+ and K+ levels in planta

The ratio of Na+ and K+ is an important determinant of the magnitude of Na+ toxicity and osmotic stress in plant cells. Traditional analytical approaches involve destructive tissue sampling and chemical analysis, where real-time observation of spatio-temporal experiments across genetic or breeding populations is unrealistic. Such an approach can also be very inaccurate and prone to erroneous biological interpretation. Analysis by Hyperspectral Imaging (HSI) is an emerging non-destructive alternative for tracking plant nutrient status in a time-course with higher accuracy and reduced cost for chemical analysis. In this study, the feasibility and predictive power of HSI-based approach for spatio-temporal tracking of Na+ and K+ levels in tissue samples was explored using a panel recombinant inbred line (RIL) of rice (Oryza sativa L.; salt-sensitive IR29 x salt-tolerant Pokkali) with differential activities of the Na+ exclusion mechanism conferred by the SalTol QTL. In this panel of RILs the spectrum of salinity tolerance was represented by FL499 (super-sensitive), FL454 (sensitive), FL478 (tolerant), and FL510 (super-tolerant). Whole-plant image processing pipeline was optimized to generate HSI spectra during salinity stress at EC = 9 dS m-1. Spectral data was used to create models for Na+ and K+ prediction by partial least squares regression (PLSR). Three datasets, i.e., mean image pixel spectra, smoothened version of mean image pixel spectra, and wavelength bands, with wide differences in intensity between control and salinity facilitated the prediction models with high R2. The smoothened and filtered datasets showed significant improvements over the mean image pixel dataset. However, model prediction was not fully consistent with the empirical data. While the outcome of modeling-based prediction showed a great potential for improving the throughput capacity for salinity stress phenotyping, additional technical refinements including tissue-specific measurements is necessary to maximize the accuracy of prediction models.

opencc-by-4.0May 2022View details →

Data of transgenerational effects of thermal stress in embryos of O. maya

To evaluate the transgenerational effect of thermal stress on the cephalopod Octopus maya, this study experimentally tests the morphology, respiratory metabolism, antioxidant mechanisms, and oxidative stress indicators of the embryos incubated at two temperatures (24 and 30°C) produced by females acclimated at 24 (non-stressed) and 30°C (stressed). The data set is organized in such a form that researchers will have embryo morphometric data (eye diameter, arm length, mantle length, yolk length, egg length egg wide, and wet weight of O. maya. Also, there is the oxygen consumption and antioxidant defense enzymes, oxidant damage, and esterase activity of embryos from stressed and nonstressed females. The results demonstrate that, regardless of their incubation temperature, embryos from females acclimated at 30°C are smaller, show more accelerated development, and have higher respiratory rates than those from females acclimated at 24°C. These embryos confirmed a greater oxidative stress degree, as well as an increased amount of soluble carbonylated proteins and catalase activity as the main enzyme during the activation development stage (even the highest in the embryos incubated at 30°C). Finally, a collapse of the antioxidant defense system was observed, measured as lower both CAT activity and GSH concentrations. Additionally, soluble carbonylated proteins reduced and GST activity increased in embryos incubated at 30°C from females maintained at high temperatures in a clear deleterious and transgenerational effect of thermal stress on this octopus species.

opencc-zeroMay 2022View details →

Is negative density-dependent reproduction regulated by density-induced stress in root voles? Two field experiments

Density dependence in reproduction plays an important role in stabilising population dynamics via immediate negative feedback from population density to reproductive output. Although previous studies have shown that negative density-dependent reproduction is associated with strong spacing behaviour and social interaction between individuals, the proximal mechanism for generating negative density-dependent reproduction remains unclear. In this study, we investigated the effects of density-induced stress on reproduction in root voles. Enclosed Founder populations were established by introducing six (low density) and 30 (high density) adults per sex into per enclosure (four enclosures per density in total) during the breeding season from April to July 2012 and from May to August 2015. Faecal corticosterone metabolite (FCM) levels, reproductive traits (recruitment rate and the proportion of reproductively active indivuduals), and founder population numbers were measured following repeated live-trapping in both years. The number of founders was negatively associated with recruitment rates and the proportion of reproductively active indivuduals, displaying a negative density-dependent reproduction. FCM level was positively associated with the number of founders. The number of founder females directly affected the proportion of reproductive females , and directly and indirectly through their FCM levels affected the recruitment rate; the effect of the number of male founders on the proportion of reproductive males was mediated by their FCM level. Our results showed that density-induced stress negatively affected reproductive traits and that density-induced stress is one ecological factor generating negative density-dependent reproduction.