Search

Fegra fig (Ficus palmata) is an important fruit-yielding crop and potential rootstock for grafting Ficus carica. The acclimatization phase is a pivotal step during the micropropagation of plants. During this study, the mycorrhization of micropropagated fegra fig plants with two arbuscular mycorrhizal fungi (AMF; Gigaspora margarita and Gigaspora albida) to enhance their growth and survival during the acclimatization stage was investigated. The AMF were mixed in equal proportions and the acclimatizing fegra fig plantlets were treated for 8 weeks. The leaf pigments, i.e., chlorophyll a [2.56 mg·g-1 fresh weight (FW)], chlorophyll b (1.08 mg·g-1 FW), total chlorophyll (3.67 mg·g-1 FW), and carotenoid (1.34 mg·g-1 FW), of AMF-treated plants were higher than those of non-AMF plants. The number of stomata per unit was higher in the AMF-treated plants (16.00), the density of stomata per unit area (88.40 mm²) of AMF-treated plants was similar to that of non-AMF treated plants, and the number of epidermal cells (79.00) was higher in the AMF-treated plants. The AMF-treated plants were taller and had more leaves, a greater leaf area, and higher shoot FW and dry weight. The AMF-treated plants also had the greatest total root length values, greatest surface areas of roots, and greatest total root volume and diameter compared to those of non-AMF plants. Additionally, the AMF-treated plants had a 100% survival rate, whereas a survival rate of 95% was recorded for non-AMF plants. These findings emphasize the importance of biological acclimatization of micropropagated fegra fig plants with AMF. [ABSTRACT FROM AUTHOR]

In this study, we conducted a literature review to deepen our understanding of the sweating response of the thermoregulatory system, focusing on the influence of individual characteristics and local body functions. Among the factors related to individual characteristics, improvement in aerobic fitness had a positive effect on the sweating response, whereas aging exerted an inhibitory effect. Short-term artificial acclimation and seasonal heat acclimatization promoted sweating, whereas long-term geographical acclimatization suppressed sweating. Male exhibited higher sweat rates than female when the metabolic heat production was high. Individuals with smaller surface area-to-mass ratios tended to have higher sweat rates than those with larger ratios. Regarding local body functions, sweat distribution in the resting state showed high regional sweat rates in the lower limbs and torso, with higher values in the lower limbs when in the supine position and higher values in the torso when in the seated position. During exercise, the regional sweat rates was high in the torso, whereas the limbs exhibited relatively low sweat rates. These differences in sweat distribution stem from the thermoregulatory potential of each body region, which aims to efficiently regulate body temperature. Local effects have only been examined in the thigh and forearm, with temperature coefficient Q10 ranging from 2 to 5. Only the forehead showed significantly high thermosensitivity among all body regions. [ABSTRACT FROM AUTHOR]

Background: The effects of heat acclimation (HA) on the hypothalamus after exertional heatstroke (EHS) and the specific mechanism have not been fully elucidated, and this study aimed to address these questions. Methods: In the present study, rats were randomly assigned to the control, EHS, HA, or HA + EHS groups (n = 9). Hematoxylin and eosin (H&E) staining was used to examine pathology. Tandem mass tag (TMT)-based proteomic analysis was utilized to explore the impact of HA on the protein expression profile of the hypothalamus after EHS. Bioinformatics analysis was used to predict the functions of the differentially expressed proteins. The differential proteins were validated by western blotting. An enzyme-linked immunosorbent assay was used to measure the expression levels of inflammatory cytokines in the serum. Results: The H&E staining (n = 5) results revealed that there were less structural changes in hypothalamus in the HA + EHS group compared with the EHS group. Proteomic analysis (n = 4) revealed that proinflammatory proteins such as argininosuccinate synthetase (ASS1), high mobility group protein B2 (HMGB2) and vimentin were evidently downregulated in the HA + EHS group. The levels of interleukin (IL)-1β, IL-1, and IL-8 were decreased in the serum samples (n = 3) from HA + EHS rats. Conclusions: HA may alleviate hypothalamic damage caused by heat attack by inhibiting inflammatory activities, and ASS1, HMGB2 and vimentin could be candidate factors involved in the exact mechanism. [ABSTRACT FROM AUTHOR]

Biological treatment processes at low or neutral pH are ineffective for gold mine wastewater treatment. The aim of this study was to develop a new cyanide-rich gold mine wastewater treatment system using alkaliphilic microbial consortia from the Ethiopian Rift Valley soda lake, Lake Chitu. The treatment setup incorporates aerobic and anoxic reactors connected in series and operated for about 200 treatment days. Simulated gold mine wastewater was formulated in the laboratory. Colorimetry was used to measure residual cyanide and reactive nitrogen molecules derived from cyanide biodegradation. Flocks and biofilms developed in the reactors during the acclimatization process. Using sodium cyanide at 200 mg/L as an initial concentration, the consortia degraded to 99.74 ± 0.08% of cyanide, with no significant variation (p > 0.05) occurring when the dose was increased to 800 mg/L. However, changes were observed (p < 0.05) at 1000 mg/L. Acetate was the preferred carbon source for the consortia. The established consortia effectively degraded cyanide to levels below the permissible discharge limit set by the International Cyanide Management Institute (ICMI). This study provides insights into the effectiveness of alkaliphilic microbial consortia derived from soda lakes for treating cyanide-polluted wastewater. [ABSTRACT FROM AUTHOR]

The temperature dependence of carbon assimilation—from leaf photosynthesis to ecosystem productivity—is hypothesised to be driven by the kinetics of Rubisco‐catalysed carboxylation and electron transport. However, photosynthetic physiology acclimates to changes in temperature, which may decouple temperature dependencies at higher levels of organisation from the acute temperature sensitivity of photosynthesis. Here, we integrate relative growth rate theory, metabolic theory and biochemical photosynthesis theory to develop a carbon budget model of plant growth that accounts for photosynthetic acclimation to temperature. We test its predictions using a novel experimental approach enabling concurrent measurement of the temperature sensitivity of acute photosynthesis, acclimated photosynthesis and growth rate. We demonstrate for the first time that photosynthetic acclimation mediates how carbon assimilation kinetics 'scale up' from leaf photosynthesis to whole‐plant growth. We also find that existing models of photosynthetic acclimation are unable to predict features of growth rate responses to temperature in our system. [ABSTRACT FROM AUTHOR]

OBJECTIVES: Ascending to altitudes >2500 m may lead to acute mountain sickness (AMS). METHODS: The demographics, height, weight, body mass index (BMI), smoking, and alcohol consumption of 104 healthy controls were collected in Chengdu (500 m). Heart rate (HR), saturation of pulse oxygen (SpO2), and AMS-related symptoms were collected in Hoh Xil (4200 m). A headache with Lake Louise score ≥3 was defined as AMS. RESULTS: The incidence of AMS was 60.58%. AMS group had a lower SpO2 and higher HR than non-AMS group. Alcohol consumption seemed a risk factor for AMS. There was no difference in the BMI, age, height, weight, and smoking between AMS and non-AMS groups. The most common AMS symptom was headache, followed by dyspnea, insomnia, dizziness, lassitude, and anorexia. Women were prone to suffer from dizziness. The value of SpO2 and HR was improved both in AMS and non-AMS groups after hypoxia acclimatization, and the value showed greater improvement in AMS group. Oxygen therapy decreased the AMS-induced tachycardia, which had no any effect on SpO2 and symptom alleviating time. CONCLUSION: Lower SpO2 and higher HR following exposure to high altitude were associated with AMS susceptibility. The anthropometric data changes were larger in AMS group than non-AMS group before and after hypoxia acclimatization. [ABSTRACT FROM AUTHOR]

This paper reports an efficient in vitro rooting and acclimatization method for Pennisetum 'Vertigo®'. For that purpose, the influence of the IAA (indole-3-acetic acid) in MS (Murashige and Skoog) media, and different types of LED light (100% blue, 100% red, a combination of red and blue (70% + 30%), a combination of red, blue with yellow, green, or far-red (35% + 15% + 50%), and white LED) were investigated. A fluorescent lamp and a medium without auxin were used as controls. Subsequently, the plants were transferred ex vitro in trays to the greenhouse and later transplanted into pots. In all tested combinations, the shoots rooted at a high rate of 70–100% (except under blue light). The best results were obtained under white LED or the fluorescent lamp, where the highest number of roots was formed; however, IAA did not increase the rooting rate, the number, or the weight of roots. Shoots rooted under LEDs and on media containing IAA generally exhibited higher soluble sugar content compared to those rooted on auxin-free media. Consistent with the rooting results, the best acclimatization was observed in plants rooted under white LED or fluorescent light on auxin-free media. [ABSTRACT FROM AUTHOR]

Summary: Heat stress transcription factors (HSFs) are the core regulators of the heat stress (HS) response in plants. HSFs are considered as a molecular rheostat: their activities define the response intensity, incorporating information about the environmental temperature through a network of partner proteins. A prompted activation of HSFs is required for survival, for example the de novo synthesis of heat shock proteins. Furthermore, a timely attenuation of the stress response is necessary for the restoration of cellular functions and recovery from stress. In an ever‐changing environment, the balance between thermotolerance and developmental processes such as reproductive fitness highlights the importance of a tightly tuned response. In many cases, the response is described as an ON/OFF mode, while in reality, it is very dynamic. This review compiles recent findings to update existing models about the HSF‐regulated HS response and address two timely questions: How do plants adjust the intensity of cellular HS response corresponding to the temperature they experience? How does this adjustment contribute to the fine‐tuning of the HS and developmental networks? Understanding these processes is crucial not only for enhancing our basic understanding of plant biology but also for developing strategies to improve crop resilience and productivity under stressful conditions. [ABSTRACT FROM AUTHOR]

Over the past four decades, global temperatures have increased more rapidly than before, potentially reducing vegetation activity if temperatures exceed the optimum temperature (Topt). However, plants have the capacity to acclimate to rising temperatures by adjusting Topt, thereby maintaining or even enhancing photosynthesis and carbon uptake. Despite this, it remains unclear how Topt of vegetation activity changes over time and to what extent global vegetation can acclimate to current temperature changes. In this study, we evaluated the temporal trends of Topt of vegetation activity and the thermal acclimation magnitudes globally using three remote‐sensed vegetation indices and eddy‐covariance observations of gross primary productivity from 1982 to 2020. We found that the global Topt of vegetation activity has increased at an average rate of 0.63°C per decade over the past four decades. The increase in Topt closely tracked the rise in annual maximum daily mean temperature (Tmax), indicating that thermal acclimation has occurred widely across the globe. Globally, we found an average thermal acclimation magnitude of 0.38°C per 1°C increase in Tmax. Notably, polar and continental regions exhibited the highest thermal acclimation magnitudes, while arid areas showed the lowest. Additionally, the thermal acclimation magnitude was positively affected by interannual temperature variability and negatively affected by soil moisture and vapor pressure deficits. Our findings indicate that terrestrial ecosystems have acclimated to current climate warming trends with varying degrees, suggesting a greater potential for land carbon uptake. Moreover, these results highlight the necessity for earth system models to integrate the thermal acclimation of Topt to better forecast the global carbon cycle. Plain Language Summary: Global warming affects vegetation growth, and plants may acclimate to temperature changes to enhance their growth and activity. However, how effectively global vegetation can adjust to temperature changes is unclear. To examine this, we analyzed satellite and ground data from 1982 to 2020 to determine changes in the optimum temperature of vegetation activity. We found that global vegetation has acclimated to rising temperatures by increasing the optimum temperatures. Polar and continental vegetation have undergone the greatest acclimation. In addition, ecosystems with humid climates and higher temperature variability have a greater capacity to acclimate to rising temperatures. These findings have important implications for better predicting how warming will affect the global carbon cycle. Key Points: The optimum temperature (Topt) of global vegetation activity has increased rapidly, by 0.63 per decade over 1982–2020The increase in Topt closely tracked the increase in air temperature, revealing widespread thermal acclimation across global vegetationContinental and polar ecosystems showed the greatest capacity for acclimation [ABSTRACT FROM AUTHOR]

Animals frequently engage in anti-predator behaviour, but the intensity and choice of behaviour is likely dependent on the environment. We used a common-garden experiment to test whether Allenby's gerbils (Gerbillus andersoni allenbyi) from different sites in the Negev Desert show different responses to the same level of risk. We tested whether animals from less covered (more risky) environments cope with predation risk better by foraging longer and faster in open microhabitats. To do so, we captured individuals from three areas that differ in vegetation cover and then quantified food consumption and apprehension in a standard outdoor vivarium (an enclosure). This vivarium simulated a natural environment, with natural moonlight, artificial cover, and two live owls. Animals from less vegetated environments consumed more food but foraged slower and with more apprehension. We also found that some populations prefer to forage more in the first quarter of the lunar cycle than the third, and others prefer the opposite, despite these moon phases having equal luminosity. That suggests an evolutionary coordination game might be at play. Our results show anti-predator behaviour is diverse among populations and similar within, which may hint the existence of different ecotypes if further differences are found. Significance statement: In this study, we analysed whether anti-predator behaviour is consistent within populations, and different among them. We found that gerbils have different anti-predator behaviour depending on their site of origin, and that difference continues even when placed in a common environment. Animals from environments poor in cover foraged slowly and more carefully but did so for a longer time. Interestingly, we also found that when animals from different locations are placed in the same environment together, the average behaviour of this mixed group is similar to the most cautious of the mix. [ABSTRACT FROM AUTHOR]

Introduction: Upside-down jellyfish (Cassiopea sp.) are highly tolerant to multiple abiotic stressors, including fluctuating temperatures associated with shallow marine habitats. This resilience may underlie the ability of Cassiopea sp. to inhabit a wide variety of tropical habitats across the globe. Additionally, Cassiopea sp. are marked by a conspicuous array of appendage coloration; individual medusae vary in the hue and number of oral appendages, which are often strikingly blue. The function of this coloration is not understood. We aimed to understand how extrinsic (temperature, location) and intrinsic (host color) factors may shape thermal tolerance. Methods: Adult Cassiopea xamachana were collected from two sites that vary in daily temperature range within the Florida Keys and were subjected to acute lethal heat stress. To quantify a whole-organism response to heat, we measured changes in bell pulsation, which likely plays a role in feeding, oxygen exchange, and symbiont uptake. Finally, color morphs were acclimated at either ambient (26°C) or elevated (33°C) temperatures. Results: C. xamachana from two locations that vary in thermal range do not exhibit different responses to heat, suggesting that temperature fluctuations do not prime individuals for higher thermal tolerance. Additionally, C. xamachana with blue appendages survived significantly higher temperatures and exhibited less change in bell pulsation rates compared to non-blue individuals. We found that acclimation at 33°C, as well as appendage color in each treatment, led to higher survival under acute heat stress. Discussion: These findings highlight the importance of temperature and coloration in Cassiopea xamachana resilience during heat stress. [ABSTRACT FROM AUTHOR]

This article discusses the genetic basis of high-altitude adaptation in both human populations and animal species that live in high-altitude environments. Researchers have used genomic studies and molecular analyses to identify specific genes and genetic variations that are involved in the physiological responses to high-altitude environments. The study found that as altitude increases, there is an increase in genetic variability, and identified several genes, such as EPAS1 and EGLN1, that are associated with high-altitude adaptation. Understanding the genetic and epigenetic basis of high-altitude adaptation has potential implications for medicine and improving human health and resilience in challenging environments. Additionally, the document provides a list of scientific articles and studies that explore high-altitude adaptation in various populations, including Tibetans, Andeans, Peruvian Quechua, and Ethiopians. These studies examine genetic and physiological factors that contribute to the ability of these populations to adapt to high-altitude environments, covering topics such as natural selection, genetic signatures, DNA methylation changes, gene expression, and the role of specific genes in high-altitude adaptation. Overall, these articles offer valuable insights into the genetic and physiological mechanisms underlying human adaptation to extreme environments. [Extracted from the article]

Phytoplankton are a major source of primary productivity. Their photosynthetic fluorescence are unique measures of their type, physiological state, and response to environmental conditions. Changes in phytoplankton photophysiology are commonly monitored by bulk fluorescence spectroscopy, where gradual changes are reported in response to different perturbations, such as light intensity changes. What is the meaning of such trends in bulk parameters if their values report ensemble averages of multiple unsynchronized cells? To answer this, we developed an experimental scheme that enables tracking fluorescence intensities, brightnesses, and their ratios, as well as mean photon nanotimes equivalent to mean fluorescence lifetimes, one cell at a time. We monitored three different phytoplankton species during diurnal cycles and in response to an abrupt increase in light intensity. Our results show that we can define specific subpopulations of cells by their fluorescence parameters for each of the phytoplankton species, and in response to varying light conditions. Importantly, we identify the cells undergo well‐defined transitions between these subpopulations. The approach shown in this work will be useful in the exact characterization of phytoplankton cell states and parameter signatures in response to different changes these cells experience in marine environments, which will be applicable for monitoring marine‐related environmental effects. [ABSTRACT FROM AUTHOR]

Summary Xylem air embolism is the primary cause of drought‐related tree mortality. Phenotypic plasticity of xylem traits is key for species acclimation to environmental variability and evolution. It is widely believed that plants increase xylem embolism resistance in response to drought. However, I argue that this hypothesis, based on extensive literature, relies on sampling methods that overlook predictable anatomical patterns, potentially biasing our understanding of acclimation and adaptation strategies. [ABSTRACT FROM AUTHOR]

Salinity is a crucial environmental factor that influences the growth, reproduction, and physiological responses of fish species. Understanding how different salinities affect Liza ramada is essential for selecting optimal conditions for aquaculture. This study aimed to assess the effects of salinity on the growth, osmoregulation, stress response, and maturation of L. ramada in captivity. In this investigation, blood levels of hormones related to growth, adaptation, and stress response were measured, along with glucose levels in L. ramada broodstock raised in the waters of varying salinities. Results indicated that prolactin and growth hormone levels were higher in freshwater and lower in saline conditions. Additionally, these hormone levels increased during gonad maturation across all salinities. In contrast, thyroxine concentrations exhibited a pattern similar to cortisol, with significantly higher levels in saline water compared to freshwater. Mature fish also displayed elevated hormone levels. Glucose concentrations in the fish raised in different salinities followed a similar trend to cortisol levels. Furthermore, triiodothyronine hormone levels varied slightly during maturation and across different salinities. The L. ramada stock in freshwater demonstrated superior growth rates in both length and weight, alongside higher condition factor and survival rates. However, broodstock grown in freshwater had a lower food conversion ratio. In saline environments, L. ramada exhibited increased sexual activity, with a higher frequency of mature gonad stages and elevated values of the gonadosomatic index (GSI) and hepatosomatic index (HSI). In light of these findings, we conclude that freshwater is conducive to the growth of L. ramada, while saline water is essential for achieving sexual maturity. [ABSTRACT FROM AUTHOR]

Background: Barometric whole‐body plethysmography (BWBP) is used as a noninvasive method to assess lung function in cats with lower airway disease (LAD). The duration of the acclimatization period in the measuring chamber varies between the studies. Objectives: To assess the influence of acclimatization time on variables indicative of lung function. Animals: Twenty‐four client‐owned cats with LAD and 8 healthy cats. Methods: In the prospective case‐control study for each cat, a 30‐minute dataset was collected. Data for the three 10‐minute periods were statistically compared. Results: The variables pause (T1 median: 0.8, range: [0.7‐1]; T3: 0.9 [0.8‐1.1]; P ≤.01), peak inspiratory flow (PIF; T1: 84.9 [71.6‐112.7]; T3: 75 [63.6‐108.3]; P ≤.001), peak expiratory flow (PEF; T1: 53.2 [41.5‐76.6]; T3: 42.5 [34.6‐57.8]; P ≤.01), and a quotient of PEF and expiratory flow at 50% expired volume (PEF/EF50; T1: 1.2 [1.1‐1.4]; T3: 1.2 [1.1‐1.5]; P ≤.01) varied significantly between first and third time period in cats with LAD. In healthy cats PIF (T1: 76.4 [66.3‐85.2]; T2: 69.5 [58.3‐85.2]; P ≤.01), PEF (T1: 40 [32.8‐58.6]; T2: 34.3, [29.8‐44.6]; P ≤.01), and PEF/EF50 (T1: 13.1 [11.6‐14.6]; T3: 13.6 [12.4‐16.3]; P ≤.01) changed significantly between first and second time period. Enhanced pause did not change significantly in either group. Conclusions and Clinical Importance: Acclimatization time has a significant influence on multiple variables in BWBP. Manual correction of the data for tidal breathing flow‐volume loop might be necessary. [ABSTRACT FROM AUTHOR]

Contemporary symbioses in extreme environments can give an insight into mechanisms that stabilize species interactions during environmental change. The intertidal sea anemone, Anthopleura elegantissima, engages in a nutritional symbiosis with microalgae similar to tropical coral, but withstands more intense environmental fluctuations during tidal inundations. In this study, we compare baseline symbiotic traits and their sensitivity to thermal stress within and among anemone aggregations across the intertidal using a laboratory‐based tank experiment to better understand how fixed genotypic and plastic environmental effects contribute to the successful maintenance of this symbiosis in extreme habitats. High intertidal anemones had lower baseline symbiont‐to‐host cell ratios under control conditions, but their symbionts had higher baseline photosynthetic efficiency compared to low intertidal anemone symbionts. Symbiont communities were identical across all samples, suggesting that shifts in symbiont density and photosynthetic performance could be an acclimatory mechanism to maintain symbiosis in different environments. Despite lower baseline symbiont‐to‐host cell ratios, high intertidal anemones maintained greater symbiont‐to‐host cell ratios under heat stress compared with low intertidal anemones, suggesting greater thermal tolerance of high intertidal holobionts. However, the thermal tolerance of clonal anemones acclimatized to different zones was not explained by tidal height alone, indicating additional environmental variables contribute to physiological differences. Host genotype significantly influenced anemone weight, but only explained a minor proportion of variation among symbiotic traits and their response to thermal stress, further implicating environmental history as the primary driver of holobiont tolerance. These results indicate that this symbiosis is highly plastic and may be able to acclimatize to climate change over ecological timescales, defying the convention that symbiotic organisms are more susceptible to environmental stress. [ABSTRACT FROM AUTHOR]

Cold acclimation before winter has been shown to enhance the cold tolerance of evergreen conifers, including Pinus massoniana Lamb., a characteristic heteroblastic foliage tree in the conifer. In the initial growing season of P. massoniana, both primary needle seedlings (PNSs) and secondary needle seedlings (SNSs) are generated. While previous research has highlighted differences in the morphological structure and photosynthetic physiological functions of primary and secondary needles, their response to cold acclimation remains poorly understood. This study aimed to investigate the changes in morpho-anatomical structure, starch grain accumulation, and lignin deposition in the roots, stems, and leaves of PNSs and SNSs during cold acclimation using solid potassium iodide and hydrochloric acid phloroglucinol double-staining techniques. The results revealed that, during cold acclimation, the leaves and stems of PNSs exhibited sensitivity to low-temperature stress, resulting in noticeable shrinkage and fracture of mesophyll and cortical parenchyma cells. Furthermore, the early stages of cold acclimation promoted the accumulation of starch grains and lignin in the seedling tissues. In contrast to PNSs, the leaves and stems of SNSs exhibited a shorter cold acclimation period, attributed to the hydrolysis of starch grains in the epidermal cell walls and the transformation of xylem lignin, which supports cell structure stability and enhances cold resistance. In conclusion, these findings suggest that SNSs displayed a superior cold resistance potential compared to PNSs following cold acclimation, providing a significant theoretical basis for the further screening of cold-tolerant germplasm resources of P. massoniana and the analysis of cold resistance traits in heteroblastic foliage. [ABSTRACT FROM AUTHOR]

The efficient doubled haploid (DH) plant production methods play a key role in accelerating the breeding of new varieties and hybrids in cultivated plants. Consequently, DH plant production methods are continuously improving for barley (Hordeum vulgare L.) breeding and research programs. Two plant regeneration (FHGR and K4NB) and three rooting media (MSr, N6I and ½N6I + Ca) were compared with four F1 barley cross-combinations to clarify the effect of medium on the regeneration of green and albino plantlets and acclimatization. The plant regeneration efficiency was higher using K4NB medium (74.53 green plantlets/100 anthers and 30.85 albino/100 anthers) compared to FHGR (55.77 green plantlets/100anthers and 21.32 albino/100 anthers). The percentage of acclimatization was highest when the K4NB regeneration medium was combined with the MSr rooting medium. Altogether, 61.83% of the anther culture-derived plantlets of 8 cross-combinations acclimatized to the greenhouse conditions, and 1403 acclimatized plantlets were produced from the F1 cross-combinations. Haploid (22.52%), diploid (69.37%) and tetraploid (8.11%) plantlets were identified among the 111 tested green plantlets by flow cytometric analyses. The tetraploid lines can be explored to offer new scopes for future barley research and breeding directions. Nearly one thousand DH plants have been integrated into our barley breeding program. [ABSTRACT FROM AUTHOR]

The innate immune system is the body's first line of defense against infection. Natural killer (NK) cells, a vital part of the innate immune system, help to control infection and eliminate cancer. Studies have identified a vast array of receptors that NK cells use to discriminate between healthy and unhealthy cells. However, at present, it is difficult to explain how NK cells will respond to novel stimuli in different environments. In addition, the expression of different receptors on individual NK cells is highly stochastic, but the reason for these variegated expression patterns is unclear. Here, we studied the recognition of unhealthy target cells as an inference problem, where NK cells must distinguish between healthy targets with normal variability in ligand expression and ones that are clear "outliers." Our mathematical model fits well with experimental data, including NK cells' adaptation to changing environments and responses to different target cells. Furthermore, we find that stochastic, "sparse" receptor expression profiles are best able to detect a variety of possible threats, in agreement with experimental studies of the NK cell repertoire. While our study was specifically motivated by NK cells, our model is general and could also apply more broadly to explain principles of target recognition for other immune cell types.

Up-flow sand filtration is an excellent alternative to point-of-use treatment for rural water supply. However, the sites and interval of microorganism growth in filter beds and the effect on bio-clogging remain unknown. This study aimed to assess microorganism growth based on biological activity levels using Dissolved Oxygen (DO) consumption and Field Emission Scanning Electron Microscopy (FE-SEM) imaging in various zones of the filter bed. Additionally, pressure drop was monitored to evaluate bio-clogging. The results showed that microorganism activities differed within the 0.50 m up-flow sand filter bed during 8 weeks of acclimatization. Exponential growth started after day 35, and DO levels declined to a minimum of 2 mg/L at 0.10 m bed height (measured from the bottom) after day 46. At 0.30 m and 0.50 m height, the DO decreased to 0.8 mg/L and 0.3 mg/L after days 35 and 46, respectively. FE-SEM images confirmed microorganism growth on samples from 0.1 m after 4 weeks of acclimatization. Substantial growth was seen on samples of 0.10 and 0.30 m height at 8 weeks, while lesser growth was observed on samples of 0.50 m. The pressure drop showed no significant increase, signifying that clogging did not occur during the 135-day operational period. In conclusion, the up-flow configuration prevented bio-clogging in sand filters, reducing maintenance requirements.

Abstract High altitude (HA) ascent imposes systemic hypoxia and associated risk of acute mountain sickness. Acute hypoxia elicits a hypoxic ventilatory response (HVR), which is augmented with chronic HA exposure (i.e., ventilatory acclimatization; VA). However, laboratory‐based HVR tests lack portability and feasibility in field studies. As an alternative, we aimed to characterize area under the curve (AUC) calculations on Fenn diagrams, modified by plotting portable measurements of end‐tidal carbon dioxide (PETCO2) against peripheral oxygen saturation (SpO2) to characterize and quantify VA during incremental ascent to HA (n = 46). Secondarily, these participants were compared with a separate group following the identical ascent profile whilst self‐administering a prophylactic oral dose of acetazolamide (Az; 125 mg BID; n = 20) during ascent. First, morning PETCO2 and SpO2 measurements were collected on 46 acetazolamide‐free (NAz) lowland participants during an incremental ascent over 10 days to 5160 m in the Nepal Himalaya. AUC was calculated from individually constructed Fenn diagrams, with a trichotomized split on ranked values characterizing the smallest, medium, and largest magnitudes of AUC, representing high (n = 15), moderate (n = 16), and low (n = 15) degrees of acclimatization. After characterizing the range of response magnitudes, we further demonstrated that AUC magnitudes were significantly smaller in the Az group compared to the NAz group (P = 0.0021), suggesting improved VA. These results suggest that calculating AUC on modified Fenn diagrams has utility in assessing VA in large groups of trekkers during incremental ascent to HA, due to the associated portability and congruency with known physiology, although this novel analytical method requires further validation in controlled experiments. Highlights What is the central question of this study? What are the characteristics of a novel methodological approach to assess ventilatory acclimatization (VA) with incremental ascent to high altitude (HA)? What is the main finding and its importance? Area under the curve (AUC) magnitudes calculated from modified Fenn diagrams were significantly smaller in trekkers taking an oral prophylactic dose of acetazolamide compared to an acetazolamide‐free group, suggesting improved VA. During incremental HA ascent, quantifying AUC using modified Fenn diagrams is feasible to assess VA in large groups of trekkers with ascent, although this novel analytical method requires further validation in controlled experiments.

Objective To investigate the effect of lifestyle on high-altitude de-adaptation (HADA) through questionnaire during the whole process of entering and existing the plateau in order to provide scientific basis for prevention and treatment of the disease. Methods A case-control trial was conducted on 1 751 participants from a certain unit who entered and existed the plateau together during 2021 and 2022. In 1 to 2 weeks after they returning from the plateau, they were surveyed, and finally, 1 544 valid questionnaires were obtained. According to the score of the plateau deacclimation scale ≥6 or not, the subjects were divided into plateau deacclimation group (n=192) and control group (n=1 352). They were further surveyed for their lifestyles and general conditions. Rank sum test was used to analyze the differences of lifestyles between the 2 groups, and unconditional logistic regression analysis was employed to identify the independent risk factors of HADA. Results Hair loss (19.95%), drowsiness (16.58%) and tiredness (12.31%) were the most common symptoms of HADA. High salt diet before entering the plateau, smoking at the plateau, altitude sickness (OR=1.893, 95%CI: 1.142~3.137, P=0.013), leaving the plateau by plane (OR=1.688, 95%CI: 1.082~2.634, P=0.021), and drinking much tea, excessive exercise intensity and insufficient sleep after leaving the plateau were independent risk factors for HADA. Conclusion Low salt diet before entering the plateau, active prevention for altitude sickness, smoking cessation at the plateau, taking a slower means of transportation to enter and leave the plateau, drinking less tea, moderate exercise intensity and keeping enough sleep after leaving the plateau can effectively reduce the risk of HADA.

Phytoplankton is a diverse group of photosynthetic organisms and accounts for almost half of global primary production. However, most existing marine ecosystem models incorporate limited phytoplankton diversity, overlook phytoplankton evolution, and treat phytoplankton as concentrations instead of particles. Here we present an individual-based phytoplankton model that captures three dimensions of phytoplankton traits (size, temperature, and light affinities) and allows phytoplankton cells to mutate in a one-dimensional (1D) water column. Other components of this ecosystem include dissolved inorganic nitrogen, twenty size classes of zooplankton, and detritus, all modelled as Eulerian fields. This hybrid plankton model can reproduce the general seasonal patterns of nutrients, chlorophyll, and primary production in the subtropical ocean. We expect that this model will be a useful tool for studying phytoplankton physiology, diversity and evolution in the ocean. [ABSTRACT FROM AUTHOR]

Species of springtails (Collembola) have a stratified distribution along the soil/air profile and present an opportunity to study adaptive traits relating to a gradient of fluctuating humidity. The habitat of eu-edaphic species (found in deeper litter and soil layers) secures a relatively stable humidity, whereas hemi-edaphic (found in upper litter layers) and epigeic springtails (found on soil surface or vegetation) can experience an increased range of moisture fluctuation with much more rapid shifts between extremes. We hypothesized that the capacity for acclimation to drought conditions is better developed in species associated with the soil surface than in soil-dwelling species. To test this hypothesis, we measured the osmotic response of two epigeic, two hemi-edaphic and three eu-edaphic species to mild drought acclimation (3 d at -1.5 MPa; the average wilting point of plants) and compared the drought tolerance of drought acclimated animals with controls. Epigeic species had no or very little osmotic regulation during mild drought acclimation and unexpectedly became less tolerant to subsequent acute drought stress than controls. The hemi-edaphic and eu-edaphic species significantly increased body fluid osmolality in response to mild drought acclimation. However, none of these species became more drought-tolerant after exposure to mild drought. In conclusion, we found that the osmotic response to drought acclimation was indeed related to the vertical position of a species in the soil/air profile, however, the relationship was opposite to our hypothesis. [ABSTRACT FROM AUTHOR]

The article discusses the need for standardized definitions in the field of applied physiology to improve understanding of adaptive mechanisms. The authors highlight the inconsistent use of terminology and propose a set of definitions for key terms related to adaptation. They argue that these definitions will enhance clarity and consensus in the field. The article also briefly mentions the relevance of evolutionary biology to the study of adaptation. Another article titled "The Biology of the Colonizing Ape" explores the biological factors contributing to the success of ape colonization, such as diet, locomotion, and reproductive strategies. It provides valuable insights into the evolutionary history and behavior of apes, making it a useful resource for researchers in this field. [Extracted from the article]

Effective nitrogen removal from anaerobic co-digestion is a major challenge to achieving dual-carbon goals. This study explored the acclimatization process of a lab-scale two-stage partial nitritation and anammox process of a stepwise increase in the percentage of raw anaerobic co-digestion liquor from kitchen waste, human feces, and municipal sludge in a venous industrial park in China, which has not been reported yet. Under limited dissolved oxygen (below 0.5 mg/L) and high ammonia levels (200–1500 mg/L), based on adjusting aeration rates, partial nitritation rapidly started up in 50 days. After acclimatization, partial nitritation still performed efficiently and stably, with the final total nitrogen loading rate (TNLR) of 1.24 ± 0.09 gN/L/d, nitrite accumulation rate of 99 ± 4%, and ratio of eff. nitrite/ammonia of 1.32 ± 0.13. In the anammox process, the final total nitrogen removal efficiency, total nitrogen removal rate, and TNLR reached 94 ± 5%, 1.27 ± 0.03 gN/L/d, and 1.36 ± 0.05 gN/L/d, respectively. Chemical oxygen demand (COD) was also reduced in both reactors, with COD removal rates of 0.7 gCOD/L/d in the partial nitritation and 0.4 gCOD/L/d in the anammox process. Overall, the PNA system demonstrated its feasibility in adapting to high ammonia, salinity, and iron levels, when treating anaerobic co-digestion liquor, particularly regarding resource recovery in venous industrial parks. [ABSTRACT FROM AUTHOR]

The Characterizing Arabidopsis Root Attractions (CARA) spaceflight experiment provides comparative transcriptome analyses of plants grown in both light and dark conditions within the same spaceflight. CARA compared three genotypes of Arabidopsis grown in ambient light and in the dark on board the International Space Station (ISS); Col-0, Ws, and phyD, a phytochrome D mutant in the Col-0 background. In all genotypes, leaves responded to spaceflight with a higher number of differentially expressed genes (DEGs) than root tips, and each genotype displayed distinct light / dark transcriptomic patterns that were unique to the spaceflight environment. The Col-0 leaves exhibited a substantial dichotomy, with ten-times as many spaceflight DEGs exhibited in light-grown plants versus dark-grown plants. Although the total number of DEGs in phyD leaves is not very different from Col-0, phyD altered the manner in which light-grown leaves respond to spaceflight, and many genes associated with the physiological adaptation of Col-0 to spaceflight were not represented. This result is in contrast to root tips, where a previous CARA study showed that phyD substantially reduced the number of DEGs. There were few DEGs, but a series of space-altered gene categories, common to genotypes and lighting conditions. This commonality indicates that key spaceflight genes are associated with signal transduction for light, defense, and oxidative stress responses. However, these key signaling pathways enriched from DEGs showed opposite regulatory direction in response to spaceflight under light and dark conditions, suggesting a complex interaction between light as a signal, and light-signaling genes in acclimation to spaceflight. [ABSTRACT FROM AUTHOR]

'Jayanti Agrihorti' is a superior chrysanthemum therefore rooted cuttings quality is required. In vitro propagation increases the rate of propagation and produces true-to-type plants. The research to obtain the best explants and culture medium composition that is capable of producing high-quality plants. The research was arranged in a randomized complete block design consisting of two factors. The first factor was the explant, including the apical shoot of 0.5 cm, 1.0 cm, and the nodal segment. The second factor was in vitro culture medium composition (CP), consisting of CP1 (Murashige and Skoog (MS) medium for initiation, followed by MS + 2.5 mg.L-1 gibberellic acid (GA3) for subculture), CP2 (MS + 0.25 mg.L-1 benzyl amino purine (BAP) for initiation, followed by MS for subculture), CP3 (MS + 0.25 mg.L-1 BAP for initiation, followed by MS + 2.5 mg.L-1 GA3 for subculture), and CP4 (MS + 0.5 mg.L-1 BAP for initiation, followed by MS + 0.25 mg.L-1 BAP for subculture). Acclimatization was performed after third subculture. The apical shoot size of 0.5-1.0 cm is optimum for producing chrysanthemum-rooted cuttings. Meanwhile, MS medium for initiation stage, followed by MS + 2.5 mg.L-1 GA3 for subculture is the best culture medium composition for in vitro propagation. This explant and culture medium composition produced higher chlorophyll a, b, and a+b content, thereby resulting in higher plant, more leaves, larger stem diameter, and longer root length. This are recommended for chrysanthemum propagation, particularly in 'Jayanti Agrihorti'. [ABSTRACT FROM AUTHOR]

Temperature and resource availability are pivotal factors influencing phytoplankton community structures. Numerous prior studies demonstrated their significant influence on phytoplankton stoichiometry, cell size, and growth rates. The growth rate, serving as a reflection of an organism's success within its environment, is linked to stoichiometry and cell size. Consequently, alterations in abiotic conditions affecting cell size or stoichiometry also exert indirect effects on growth. However, such results have their limitations, as most studies used a limited number of factors and factor levels which gives us limited insights into how phytoplankton respond to environmental conditions, directly and indirectly. Here, we tested for the generality of patterns found in other studies, using a combined multiple‐factor gradient design and two single species with different size characteristics. We used a structural equation model (SEM) that allowed us to investigate the direct cumulative effects of temperature and resource availability (i.e., light, N and P) on phytoplankton growth, as well as their indirect effects on growth through changes in cell size and cell stoichiometry. Our results mostly support the results reported in previous research thus some effects can be identified as dominant effects. We identified rising temperature as the dominant driver for cell size reduction and increase in growth, and nutrient availability (i.e., N and P) as dominant factor for changes in cellular stoichiometry. However, indirect effects of temperature and resources (i.e., light and nutrients) on species' growth rates through cell size and cell stoichiometry differed across the two species suggesting different strategies to acclimate to its environment. [ABSTRACT FROM AUTHOR]

How species thrive in a wide range of environments is a major focus of evolutionary biology. For many species, limited genetic diversity or gene flow among habitats means that phenotypic plasticity must play an important role in their capacity to tolerate environmental heterogeneity and to colonize new habitats. However, we have a limited understanding of the molecular components that govern plasticity in ecologically relevant phenotypes. We examined this hypothesis in a spider species (Stegodyphus dumicola) with extremely low species-wide genetic diversity that nevertheless occupies a broad range of thermal environments. We determined phenotypic responses to temperature stress in individuals from four climatic zones using common garden acclimation experiments to disentangle phenotypic plasticity from genetic adaptations. Simultaneously, we created data sets on multiple molecular modalities: the genome, the transcriptome, the methylome, the metabolome, and the bacterial microbiome to determine associations with phenotypic responses. Analyses of phenotypic and molecular associations reveal that acclimation responses in the transcriptome and metabolome correlate with patterns of phenotypic plasticity in temperature tolerance. Surprisingly, genes whose expression seemed to be involved in plasticity in temperature tolerance were generally highly methylated contradicting the idea that DNA methylation stabilizes gene expression. This suggests that the function of DNA methylation in invertebrates varies not only among species but also among genes. The bacterial microbiome was stable across the acclimation period; combined with our previous demonstrations that the microbiome is temporally stable in wild populations, this is convincing evidence that the microbiome does not facilitate plasticity in temperature tolerance. Our results suggest that population-specific variation in temperature tolerance among acclimation temperatures appears to result from the evolution of plasticity in mainly gene expression. [ABSTRACT FROM AUTHOR]

The present study was conducted to understand transcriptional response of skin fibroblast of yak (Bos grunniens) and cows of Bos indicus origin to hypoxia stress. Six primary fibroblast cell lines derived from three individuals each of Ladakhi yak (Bos grunniens) and Sahiwal cows (Bos indicus) were exposed to low oxygen concentration for a period of 24 h, 48 h and 72 h. The expression of 10 important genes known to regulate hypoxia response such as HIF1A, VEGFA, EPAS1, ATP1A1, GLUT1, HMOX1, ECE1, TNF-A, GPx and SOD were evaluated in fibroblast cells of Ladakhi yak (LAY-Fb) and Sahiwal cows (SAC-Fb) during pre- and post-hypoxia stress. A panel of 10 reference genes (GAPDH, RPL4, EEF1A1, RPS9, HPRT1, UXT, RPS23, B2M, RPS15, ACTB) were also evaluated for their expression stability to perform accurate normalization. The expression of HIF1A was significantly (p < 0.05) induced in both LAY-Fb (2.29-fold) and SAC-Fb (2.07-fold) after 24 h of hypoxia stress. The angiogenic (VEGFA), metabolic (GLUT1) and antioxidant genes (SOD and GPx) were also induced after 24 h of hypoxia stress. However, EPAS1 and ATP1A1 induced significantly (p < 0.05) after 48 h whereas, ECE1 expression induced significantly (p < 0.05) at 72 h after exposure to hypoxia. The TNF-alpha which is a pro-inflammatory gene induced significantly (p < 0.05) at 24 h in SAC-Fb and at 72 h in LAY-Fb. The induction of hypoxia associated genes indicated the utility of skin derived fibroblast as cellular model to evaluate transcriptome signatures post hypoxia stress in populations adapted to diverse altitudes. [ABSTRACT FROM AUTHOR]

Since the early 1900s, repeated heat exposure has been used as a method to induce physiological adaptations that enhance our ability to tolerate heat stress during athletic and occupational pursuits. Much of this work has been dedicated to quantifying the time course of adaptation and identifying the minimum duration of acclimation required to optimise performance or enhance safety. To achieve this, investigators have typically applied classical (constant load) heat acclimation, whereby 60–90 min exercise is performed at the same absolute or relative intensity in a hot environment for 3–24 days, with adaptations evaluated using an identical forcing function test before and after. This approach has provided a foundation from which to develop our understanding of changes in thermoregulatory function, but it has several, frequently overlooked shortcomings, which have resulted in misconceptions concerning the time course of adaptation. It is frequently suggested that most of the thermoregulatory adaptations during heat acclimation occur within a week, but this is an oversimplification and a predictable artefact of the experimental designs used. Consequently, the time course of complete human adaptation to heat remains poorly understood and appears to vary considerably due to numerous individual factors. The purpose of this communication is to highlight the key methodological considerations required when interpreting the existing literature documenting adaptation over time. We also propose potential means by which to improve the way we induce and quantify the magnitude of adaptation to expedite discovery. [ABSTRACT FROM AUTHOR]

High-altitude acclimatization refers to the physiological adjustments and adaptation processes by which the human body gradually adapts to the hypoxic conditions of high altitudes after entering such environments. This study analyzed three mRNA expression profile datasets from the GEO database, focusing on 93 healthy residents from low altitudes (≤1400 m). Peripheral blood samples were collected for analysis on the third day after these individuals rapidly ascended to higher altitudes (3000–5300 m). The analysis identified significant differential expression in 382 genes, with 361 genes upregulated and 21 downregulated. Further, gene ontology (GO) annotation analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis indicated that the top-ranked enriched pathways are upregulated, involving blood gas transport, erythrocyte development and differentiation, and heme biosynthetic process. Network analysis highlighted ten key genes, namely, SLC4A1, FECH, EPB42, SNCA, GATA1, KLF1, GYPB, ALAS2, DMTN, and GYPA. Analysis revealed that two of these key genes, FECH and ALAS2, play a critical role in the heme biosynthetic process, which is pivotal in the development and maturation of red blood cells. These findings provide new insights into the key gene mechanisms of high-altitude acclimatization and identify potential biomarkers and targets for personalized acclimatization strategies. [ABSTRACT FROM AUTHOR]

Temporary immersion system (TIS) cultures are reported to be superior when compared to semi-solid (SS) and liquid (LQ) cultures for the in vitro plant regeneration of many plant species. In the present study, we used a TIS for plant regeneration of Gerbera jemesonii "Shy Pink" and compared the results with that of SS and LQ cultures. The number of shoots regenerated in the SS, LQ, and TIS cultures was 6.93, 3.13, and 3.03, respectively. The shoots regenerated with the SS and LQ cultures demonstrated 3.33 and 4.22% hyperhydricity, whereas the shoots regenerated with the TIS were healthy even though the number of shoots regenerated was less. The plantlets regenerated with the TIS demonstrated higher values for the number of roots, root length, biomass of the plantlets, leaf length/width, and area compared to the SS and LQ cultures. When the G. jemesonii "Shy Pink" plants were regenerated using the TIS, their levels of photosynthetic pigments were highest. The number of stomata on the abaxial surface of their leaves was 11.40, and the frequency of closed stomata was 59% for the plants regenerated with the TIS. The number of stomata was 21.4 and 14.5 for the plants regenerated with the SS and LQ cultures, respectively. Meanwhile, the frequency of closed stomata was 13% and 15% for the plants regenerated with SS and LQ cultures. Furthermore, G. jemesonii "Shy Pink" showed the highest survival of plants when regenerated in the TIS compared to SS and LQ cultures. The TIS was found to be the most suitable culture system for plant regeneration of G. jemesonii "Shy Pink" compared to SS and LQ cultures. [ABSTRACT FROM AUTHOR]

Climate change is transforming coral reefs by increasing the frequency and intensity of marine heatwaves, often leading to coral bleaching and mortality. Coral communities have demonstrated modest increases in thermal tolerance following repeated exposure to moderate heat stress, but it is unclear whether these shifts represent acclimatization of individual colonies or mortality of thermally susceptible individuals. For corals that survive repeated bleaching events, it is important to understand how past bleaching responses impact future growth potential. Here, we track the bleaching responses of 1,832 corals in leeward Maui through multiple marine heatwaves and document patterns of coral growth and survivorship over a seven-year period. While we find limited evidence of acclimatization at population scales, we document reduced bleaching over time in specific individuals that is indicative of acclimatization, primarily in the stress-tolerant taxa Porites lobata. For corals that survived both bleaching events, we find no relationship between bleaching response and coral growth in three of four taxa studied. This decoupling suggests that coral survivorship is a better indicator of future growth than is a coral's bleaching history. Based on these results, we recommend restoration practitioners in Hawaiʻi focus on colonies of Porites and Montipora with a proven track-record of growth and survivorship, rather than devote resources toward identifying and cultivating bleaching-resistant phenotypes in the lab. Survivorship followed a latitudinal thermal stress gradient, but because this gradient was small, it is likely that local environmental factors also drove differences in coral performance between sites. Efforts to reduce human impacts at low performing sites would likely improve coral survivorship in the future. [ABSTRACT FROM AUTHOR]

Climate change is swiftly altering environmental winter conditions, leading to significant ecological impacts such as phenological shifts in many species. As a result, animals might face physiological mismatches due to longer or earlier activity periods and are at risk of being exposed to late spring freezes. Our study points for the first time to the complex physiological challenges that amphibians face as a result of changing thermal conditions due to winter climate change. We investigated the physiological responses to a period of warmer winter days and sudden spring freeze in the common toad (Bufo bufo) by acclimating them to 4°C or 8°C for 48 h or exposing them to 4°C or −2°C for 6 h, respectively. We assessed the daily energy demands, determined body condition and cold tolerance, explored the molecular responses to freezing through hepatic tissue transcriptome analysis, and measured blood glucose levels. Toads acclimated to higher temperatures showed a higher daily energy expenditure and a reduced cold tolerance suggesting faster depletion of energy stores and the loss of winter acclimation during warmer winters. Blood sugar levels were higher in frozen toads indicating the mobilization of cryoprotective glucose with freezing which was further supported by changed patterns in proteins related to glucose metabolism. Overall, our results emphasize that increased thermal variability incurs physiological costs that may reduce energy reserves and thus affect amphibian health and survival. This might pose a serious threat to breeding adults and may have subsequent effects at the population level. [ABSTRACT FROM AUTHOR]

Phenotypic plasticity can buffer organisms against short‐term environmental fluctuations. For example, previous exposure to increased temperatures can increase thermal tolerance in many species. Prior studies have found that acclimation to higher temperature can influence the magnitude of transcriptional response to subsequent acute thermal stress (hereafter, "transcriptional response modulation"). However, mechanisms mediating this gene expression response and, ultimately, phenotypic plasticity remain largely unknown. Epigenetic modifications are good candidates for modulating transcriptional response, as they broadly correlate with gene expression. Here, we investigate changes in DNA methylation as a possible mechanism controlling shifts in gene expression plasticity and thermal acclimation in the reef‐building coral Acropora nana. We find that gene expression response to acute stress is altered in corals acclimated to different temperatures, with many genes exhibiting a dampened response to heat stress in corals pre‐conditioned to higher temperatures. At the same time, we observe shifts in methylation during both acclimation (11 days) and acute heat stress (24 h). We observed that the acute heat stress results in shifts in gene‐level methylation and elicits an acute transcriptional response in distinct gene sets. Further, acclimation‐induced shifts in gene expression plasticity and differential methylation also largely occur in separate sets of genes. Counter to our initial hypothesis no overall correlation between the magnitude of differential methylation and the change in gene expression plasticity. We do find a small but statistically significant overlap in genes exhibiting both dampened expression response and shifts in methylation (14 genes), which could be candidates for further inquiry. Overall, our results suggest transcriptional response modulation occurs independently from methylation changes induced by thermal acclimation. [ABSTRACT FROM AUTHOR]

High altitude (HA) ascent imposes systemic hypoxia and associated risk of acute mountain sickness. Acute hypoxia elicits a hypoxic ventilatory response (HVR), which is augmented with chronic HA exposure (i.e., ventilatory acclimatization; VA). However, laboratory‐based HVR tests lack portability and feasibility in field studies. As an alternative, we aimed to characterize area under the curve (AUC) calculations on Fenn diagrams, modified by plotting portable measurements of end‐tidal carbon dioxide (PETCO2${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$) against peripheral oxygen saturation (SpO2${S_{{\mathrm{p}}{{\mathrm{O}}_{\mathrm{2}}}}}$) to characterize and quantify VA during incremental ascent to HA (n = 46). Secondarily, these participants were compared with a separate group following the identical ascent profile whilst self‐administering a prophylactic oral dose of acetazolamide (Az; 125 mg BID; n = 20) during ascent. First, morning PETCO2${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ and SpO2${S_{{\mathrm{p}}{{\mathrm{O}}_{\mathrm{2}}}}}$ measurements were collected on 46 acetazolamide‐free (NAz) lowland participants during an incremental ascent over 10 days to 5160 m in the Nepal Himalaya. AUC was calculated from individually constructed Fenn diagrams, with a trichotomized split on ranked values characterizing the smallest, medium, and largest magnitudes of AUC, representing high (n = 15), moderate (n = 16), and low (n = 15) degrees of acclimatization. After characterizing the range of response magnitudes, we further demonstrated that AUC magnitudes were significantly smaller in the Az group compared to the NAz group (P = 0.0021), suggesting improved VA. These results suggest that calculating AUC on modified Fenn diagrams has utility in assessing VA in large groups of trekkers during incremental ascent to HA, due to the associated portability and congruency with known physiology, although this novel analytical method requires further validation in controlled experiments. Highlights: What is the central question of this study?What are the characteristics of a novel methodological approach to assess ventilatory acclimatization (VA) with incremental ascent to high altitude (HA)?What is the main finding and its importance?Area under the curve (AUC) magnitudes calculated from modified Fenn diagrams were significantly smaller in trekkers taking an oral prophylactic dose of acetazolamide compared to an acetazolamide‐free group, suggesting improved VA. During incremental HA ascent, quantifying AUC using modified Fenn diagrams is feasible to assess VA in large groups of trekkers with ascent, although this novel analytical method requires further validation in controlled experiments. [ABSTRACT FROM AUTHOR]

The Arctic is impacted by some of the fastest temperature changes observed on Earth, but the impact on the terrestrial arthropod fauna is unclear. Acute physiological thermal limits of terrestrial ectotherms from high latitudes often exceed the local air temperatures, suggesting that they may be able to cope with increasing temperatures. However, knowledge on how Arctic terrestrial arthropods cope with elevated temperatures for longer periods is lacking.Here we investigate how acclimation temperature and exposure time affect the acute physiological heat tolerance of five terrestrial arthropod species (Neomolgus littoralis, Megaphorura arctica, Nysius groenlandicus, Psammotettix lividellus and Nabis flavomarginatus) immediately after collection in Arctic and sub‐Arctic habitats.We show that although acute heat tolerances are relatively high, even exposure to moderate (temperature span assessed ca. 3–29°C) acclimation temperatures for a 24 h period have strong negative effects on heat tolerance for four of the five species. Similarly, exposure time negatively affected heat tolerance, but depending on species and temperature.Together our results suggest that exposure to even moderately elevated temperatures for periods of 24 h or even shorter can lead to lower acute heat tolerance for cold adapted terrestrial arthropod species from sub‐Arctic and Arctic regions. Consequently, climate change leading to extended periods of mildly elevated temperatures may have strong negative effects on these species. We argue that this aspect is currently overlooked when assessing the ability of arthropods from Arctic and sub‐Artic regions to cope with climate changes as such predictions are typically based on acute heat tolerance estimates and with the assumption of beneficial acclimation responses. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Under climate change, ectotherms will likely face pressure to adapt to novel thermal environments by increasing their upper thermal tolerance and its plasticity, a measure of thermal acclimation. Ectotherm populations with high thermal tolerance are often less thermally plastic, a trade‐off hypothesized to result from (i) a phenotypic limit on thermal tolerance above which plasticity cannot further increase the trait, (ii) negative genetic correlation or (iii) fitness trade‐offs between the two traits. Whether each hypothesis causes negative associations between thermal tolerance and plasticity has implications for the evolution of each trait.We empirically tested the limit and trade‐off hypotheses by leveraging the experimental tractability and thermal biology of the intertidal copepod Tigriopus californicus. Using populations from four latitudinally distributed sites in coastal California, six lines per population were reared under a laboratory common garden for two generations. Ninety‐six full sibling replicates (n = 4–5 per line) from a third generation were developmentally conditioned to 21.5 and 16.5°C until adulthood. We then measured the upper thermal tolerance and fecundity of sibships at each temperature.We detected a significant trade‐off in fecundity, a fitness corollary, between baseline thermal tolerance and its plasticity. Tigriopus californicus populations and genotypes with higher thermal tolerance were less thermally plastic. We detected negative directional selection on thermal plasticity under ambient temperature evidenced by reduced fecundity. These fitness costs of plasticity were significantly higher among thermally tolerant genotypes, consistent with the trade‐off hypothesis. This trade‐off was evident under ambient conditions, but not high temperature.Observed thermal plasticity and fecundity were best explained by a model incorporating both the limit and trade‐off hypotheses rather than models with parameters associated with one hypothesis. Effects of population and family on tolerance and plasticity negatively covaried, suggesting that a negative genetic correlation could not be ruled as contributing to negative associations between the traits. Our study provides a novel empirical test of the fitness trade‐off hypothesis that leverages a strong inference approach. We discuss our results' insights into how thermal adaptation may be constrained by physiological limits, genetic correlations, and fitness trade‐offs between thermal tolerance and its plasticity. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Diatoms often outnumber other eukaryotic algae in the oceans, especially in coastal environments characterized by frequent fluctuations in light intensity. The identities and operational mechanisms of regulatory factors governing diatom acclimation to high light stress remain largely elusive. Here, we identified the AUREO1c protein from the coastal diatom Phaeodactylum tricornutum as a crucial regulator of non-photochemical quenching (NPQ), a photoprotective mechanism that dissipates excess energy as heat. AUREO1c detects light stress using a light-oxygen-voltage (LOV) domain and directly activates the expression of target genes, including LI818 genes that encode NPQ effector proteins, via its bZIP DNA-binding domain. In comparison to a kinase-mediated pathway reported in the freshwater green alga Chlamydomonas reinhardtii, the AUREO1c pathway exhibits a faster response and enables accumulation of LI818 transcript and protein levels to comparable degrees between continuous high-light and fluctuating-light treatments. We propose that the AUREO1c-LI818 pathway contributes to the resilience of diatoms under dynamic light conditions. Diatoms thrive in dynamic environments that frequently confer high light stress. In this study, the authors report a diatom photoreceptor that triggers immediate transcription of photoprotective genes upon high light signals. The fast response kinetics of this pathway confer advantages in environments with rapid light fluctuations. [ABSTRACT FROM AUTHOR]

Heat stroke (HS) is a critical condition with extremely high mortality. Heat acclimation (HA) is widely recognized as the best measure to prevent and protect against HS. Preventive administration of oral rehydration salts III (ORSIII) and probiotics have been reported to sustain intestinal function in cases of HS. This study established a rat model of HA that was treated with probiotics-based ORS (ORSP) during consecutive 21-day HA training. The results showed that HA with ORSP could attenuate HS-induced hyperthermia by regulating thermoregulatory response. We also found that HA with ORSP could significantly alleviate HSinduced multiple organ injuries. The expression levels of a series of heat-shock proteins (HSPs), including HSP90, HSP70, HSP60, and HSP40, were significantly up-regulated from the HA training. The increases in intestinal fatty acid binding protein (I-FABP) and D-Lactate typically seen during HS were decreased through HA. The representative TJ proteins including ZO-1, E-cadherin, and JAM-1 were found to be significantly down-regulated by HS, but sustained following HA. The ultrastructure of TJ was examined by TEM, which confirmed its protective effect on the intestinal barrier protection following HA. We also demonstrated that HA raised the intestinal levels of beneficial bacteria Lactobacillus and lowered those of the harmful bacteria Streptococcus through 16S rRNA gene sequencing. These findings suggest that HA with ORSP was proven to improve intestinal thermotolerance and the levels of protective gut microbiota against HS. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Investigación e Innovación Agropecuaria y de Recursos Naturales is the property of Revista de Investigacion e Innovacion Agropecuaria y de Recursos Naturales RIIARn and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Repeated exposure to iron oxide nanoparticles can lead to structural disorders in the testicles and have negative effects on the individual's reproductive function. On the other hand, spirulina algae can reduce these effects by having antioxidant properties and abundant vitamin source. The purpose of this study was to investigate the effects of spirulina algae on tissue changes in the testes of rats induced using iron oxide nanoparticles. After acclimatization, 36 Wistar male rats were randomly divided into the following 6 groups. The first group: control, the second group: 15 mg/kg body weight of iron oxide nanoparticles, the third group: 300 mg/kg body weight of spirulina algae, the fourth group: 15 mg/kg body weight of iron oxide nanoparticles and 300 mg/kg algae body weight. spirulina at the same time, fifth group: 15 mg/kg of body weight of iron oxide nanoparticles for 14 days, then 300 mg/kg of spirulina algae, sixth group: 300 mg/kg of body weight of spirulina algae for 14 days, then 15 mg/kg of body weight of iron oxide nanoparticles. Sampling was done after 60 days and testicular bud sections were stained by hematoxylin-eosin (H & E) after preparation for histological and histometric studies. The study of tissue sections of the testis in rats exposed to iron oxide nanoparticles showed a decrease in the diameter of the spermatogenic tubules and the thickness of the epithelium of the spermatogenic tubules, a decrease in the number of Sertoli cells and the number of Leydig cells in comparison with the control group, while exposure to spirulina algae increased the diameter of the spermatogenic tubules and the thickness of the epithelium of the spermatogenic tubules. Algae treatment in the groups exposed to iron oxide nanoparticles improved the tissue changes in the testis and prevented the decrease in the diameter of the spermatogenic tubes, the thickness of the germinal epithelium, and the number of Leydig and Sertoli cells. The results showed that the oral administration of spirulina in male rats improves the structural disorders in the testis and tissue changes caused by induction by iron oxide nanoparticles. [ABSTRACT FROM AUTHOR]

Background: Light deficit in shaded environment critically impacts the growth and development of turf plants. Despite this fact, past research has predominantly concentrated on shade avoidance rather than shade tolerance. To address this, our study examined the photosynthetic adjustments of Bermudagrass when exposed to varying intensities of shade to gain an integrative understanding of the shade response of C4 turfgrass. Results: We observed alterations in photosynthetic pigment-proteins, electron transport and its associated carbon and nitrogen assimilation, along with ROS-scavenging enzyme activity in shaded conditions. Mild shade enriched Chl b and LHC transcripts, while severe shade promoted Chl a, carotenoids and photosynthetic electron transfer beyond QA− (ET0/RC, φE0, Ψ0). The study also highlighted differential effects of shade on leaf and root components. For example, Soluble sugar content varied between leaves and roots as shade diminished SPS, SUT1 but upregulated BAM. Furthermore, we observed that shading decreased the transcriptional level of genes involving in nitrogen assimilation (e.g. NR) and SOD, POD, CAT enzyme activities in leaves, even though it increased in roots. Conclusions: As shade intensity increased, considerable changes were noted in light energy conversion and photosynthetic metabolism processes along the electron transport chain axis. Our study thus provides valuable theoretical groundwork for understanding how C4 grass acclimates to shade tolerance. [ABSTRACT FROM AUTHOR]

Certain cyanobacteria alter their photosynthetic light absorption between green and red, a phenomenon called complementary chromatic acclimation. The acclimation is regulated by a cyanobacteriochrome-class photosensor that reversibly photoconverts between green-absorbing (Pg) and red-absorbing (Pr) states. Here, we elucidated the structural basis of the green/red photocycle. In the Pg state, the bilin chromophore adopted the extended C15-Z,anti structure within a hydrophobic pocket. Upon photoconversion to the Pr state, the bilin is isomerized to the cyclic C15-E,syn structure, forming a water channel in the pocket. The solvation/desolvation of the bilin causes changes in the protonation state and the stability of π-conjugation at the B ring, leading to a large absorption shift. These results advance our understanding of the enormous spectral diversity of the phytochrome superfamily. [ABSTRACT FROM AUTHOR]

Summary: Multivariate leaf trait correlations are hypothesized to originate from natural selection on carbon economics traits that control lifetime leaf carbon gain, and energy balance traits governing leaf temperatures, physiological rates, and heat injury. However, it is unclear whether macroevolution of leaf traits primarily reflects selection for lifetime carbon gain or energy balance, and whether photosynthetic heat tolerance is coordinated along these axes.To evaluate these hypotheses, we measured carbon economics, energy balance, and photosynthetic heat tolerance traits for 177 species (157 families) in a common garden that minimizes co‐variation of taxa and climate.We observed wide variation in carbon economics, energy balance, and heat tolerance traits. Carbon economics and energy balance (but not heat tolerance) traits were phylogenetically structured, suggesting macroevolution of leaf mass per area and leaf dry matter content reflects selection on carbon gain rather than energy balance. Carbon economics and energy balance traits varied along a common axis orthogonal to heat tolerance traits.Our results highlight a fundamental mismatch in the timescales over which morphological and heat tolerance traits respond to environmental variation. Whereas carbon economics and energy balance traits are constrained by species' evolutionary histories, photosynthetic heat tolerance traits are not and can acclimate readily to leaf microclimates. [ABSTRACT FROM AUTHOR]

Here we address the combined impact of multiple stressors that are becoming more common with climate change. To study the combined effects of a lower water table (WT) and increased frequency of drought periods on the resistance and resilience of peatlands, we conducted a mesocosm experiment. This study evaluated how the photosynthesis of lawn Sphagnum mosses responds to and recovers from an experimental periodic drought after exposure to the stresses of a deep or deepened WT (naturally dry and 17‐year‐long water level drawdown [WLD] in fen and bog environments).We aimed to quantify if deep WTs (1) support acclimation to drought, or (2) increase the base‐level physiological stress of mosses or (3) exacerbate the impact of periodic drought.There was no evidence of acclimation in mosses from drier environments; periodic drought decreased the photosynthesis of all Sphagnum species studied. WLDdecreased the photosynthesis of bog‐originating mosses prior to periodic drought, indicating that these mosses were stressed by the hydrological change. Deep WTs exacerbated Sphagnum vulnerability to periodic drought, indicating that the combination of drying habitats and increasing frequency of periodic drought could lead to a rapid transition in lawn vegetation. Water‐retaining traits may increase Sphagnum resilience to periodic drought. Large capitula size was associated with a higher resistance; the bog originating species studied here lacked large capitula or dense carpet structure and were more vulnerable to drought than the larger fen originating species. Consequently, lawns in bogs may become threatened.Recovery after rewetting was significant for all mosses, but none completely recovered within 3 weeks. The most drought‐resilient species had fen origin, indicating that fens are less likely to undergo a sudden transition due to periodic drought.Synthesis: Water level drawdown associated with climate change increases the sensitivity of Sphagnum mosses to periods of drought and moves them closer to their tipping point as species on the edge of their ecological envelope rapidly shut down photosynthesis and recover poorly. [ABSTRACT FROM AUTHOR]

Ideas, knowledge, people, and animals were in rapid transit in the nineteenth century, occasionally at the same time. This essay analyzes the unsuccessful government-sponsored experiment to introduce and naturalize dromedaries (Camelus dromedarius) in the northeastern Brazilian province of Ceará between 1857 and 1867. While the scheme is not unknown, it has not yet received a dedicated and thorough examination. Using the lenses of the global exchange of knowledge, transnational scientific enterprises, the history of camelids, and the worldwide phenomenon of acclimatization, the essay seeks to argue that the naturalization plan was tailored following the principles of animal acclimatization while aimed at wider efforts by the Brazilian government to modernize national agriculture. In practice, it meant employment of the dromedaries as livestock and pack animals, moves that sought to address logistics problems in the region. Finally, by reviewing primary sources and scholarship, the essay provides a comprehensive narrative of the events relating to the scheme. [ABSTRACT FROM AUTHOR]