Adaptive mechanism of the marine bacterium Pseudomonas sihuiensis-BFB-6S towards pCO2 variation: Insights into synthesis of extracellular polymeric substances and physiochemical modulation

Marine bacteria can adapt to various extreme environments by the production of extracellular polymeric substances (EPS). Throughout this investigation, impact of variable pCO2 levels on the metabolic activity and physiochemical modulation in EPS matrix of marine bacterium Pseudomonas sihuiensis - BFB-6S was evaluated using a fluorescence microscope, excitation-emission matrix (EEM), 2D-Fourier transform infrared correlation spectroscopy (2D-ATR-FTIR-COS), FT-NMR and TGA-DSC. From the results at higher pCO2 levels, there was a substantial reduction in EPS production by 58-62.8 % (DW). In addition to the biochemical composition of EPS, reduction in carbohydrates (8.7-47.6 %), protein (7.1-91.5 %), and lipids (16.9-68.6 %) content were observed at higher pCO2 levels. Functional discrepancies of fluorophores (tyrosine and tryptophan-like) in EPS, speckled differently in response to variable pCO2. The 2D-ATR-FTIR-COS analysis revealed functional amides (CN, CC, CO bending, -NH bending in amines) of EPS were preferentially altered, which led to the domination of polysaccharides relevant functional groups at higher pCO2. 1H NMR analysis of EPS confirmed the absence of chemical signals from H-C-COOH of proteins, α, β anomeric protons, and acetyl group relevant region at higher pCO2 levels. These findings can contribute new insights into the influence of pCO2 on the adaptation of marine microbes in future ocean acidification scenarios.

An assessment of ozone risk for date palm suggests that phytotoxic ozone dose nonlinearly affects carbon gain

Tropospheric ozone (O3) is a significant phytotoxic air pollutant that has a negative impact on plant carbon gain. Although date palm (Phoenix dactylifera L.) is a globally important crop in arid or semi-arid regions, so far O3 risk assessment for this species has not been reported. This study estimated leaf- and plant-level photosynthetic CO2 uptake for understanding how elevated levels of O3 affects date palm biomass growth. Ozone risks to date palm plants were assessed based on exposure- (AOT40) or flux-based indices (Phytotoxic Ozone Dose, PODy, where y is a threshold of uptake). For this purpose, plants were exposed to three levels of O3 [ambient air, AA (45 ppb as daily average); 1.5 × AA; 2.0 × AA] for 92 days in an O3 Free-Air Controlled Exposure facility. According to the model simulations, the negative effects of O3 on plant-level net photosynthetic CO2 uptake were attributed to reduced gross photosynthetic carbon gain and increased respiratory carbon loss. Season-long O3 exposure and elevated temperatures promoted the negative O3 effect because of a further increase of respiratory carbon loss, which was caused by increased leaf temperature due to stomatal closure. POD1 nonlinearly affected the photosynthetic CO2 uptake, which was closely related to the variation of dry mass increment during the experiment. Although the dose-response relationship suggested that a low O3 dose (POD1 < 5.2 mmol m-2) may even positively affect photosynthetic CO2 uptake in date palms, stomatal O3 uptake at the current ambient O3 levels has potentially a negative impact on date palm growth. The results indicate 5.8 mmol m-2 POD1 or 21.1 ppm h AOT40 as critical levels corresponding to a 4% reduction of net CO2 uptake for date palm, suggesting that this species can be identified as a species moderately sensitive to O3.

Exogenous glycine betaine alleviates water-deficit stress in Indian pennywort (Centella asiatica) under greenhouse conditions

Centella asiatica (Indian pennywort) is a green leafy vegetable containing centelloside' (triterpenoid), a key phytochemical component in traditional medicine. Being a glycophytic species, they exhibit decline in growth performance and yield traits when subjected to water-deficit (WD) conditions. Glycine betaine (GB) is a low molecular-weight organic metabolite that plays a crucial role in abiotic stress conditions in higher plants. The objective of this study was to investigate the potential of GB in alleviating water-deficit stress (in terms of morphological and physiological responses) in two different genotypes of Indian pennywort, "Nakhon Pathom" (NP; high centelloside-yielding genotype) and "Pathum Thani" (PT; low centelloside-yielding genotype). The genotypes of Indian pennywort were propagated by stolon cutting and transplanted into plastic bags containing 2 kg of garden soil. At the flower-initiation stage (30 days after transplantation), uniform plant material was treated exogenously with 0 (control), 25, and 50 mM GB at 100 mL per plant (one-time foliar spray) and then divided into two groups, 1) well watered (WW; irrigated daily with 400 mL fresh water; 98% field capacity) and 2) water deficit (WD; withheld water for 14 days; 72% field capacity). Foliar application of GB (25 mM) significantly improved leaf osmotic potential in NP under WD conditions via osmotic adjustment by free proline and fructose. Differences in leaf temperature (Tleaf) between WD and WW in NP were maximized (+ 1.93 °C) and the gap of Tleaf was reduced in the case of 25-50 mM GB application. Similarly, crop water stress index (CWSI) in NP and PT plants under WD condition was significantly increased by 1.95- and 1.86-fold over the control, respectively; however, it was significantly decreased by exogenous GB application. Increasing Tleaf and CWSI in drought-stressed plants was closely related to stomatal closure, leading to reduced gas exchange parameters, i.e., stomatal conductance (gs), transpiration rate (E), net photosynthetic rate (Pn), and intercellular CO2 concentration (Ci), and consequently decreased plant biomass and total centelloside yield. Overall physiological, morphological, and secondary metabolite traits were enhanced in NP under WD conditions using 25 mM GB exogenous application compared with the control. The study highlights the significance of GB in Indian pennywort production under limited water irrigation (water deficit) with higher vegetable yield and phytochemical stabilization.

Pregnancy-related maternal physiological adaptations and fetal chemical exposure

Prenatal life represents a susceptible window of development during which chemical exposures can permanently alter fetal development, leading to an increased likelihood of disease later in life. Therefore, it is essential to assess exposure in the fetus. However, direct assessment in human fetuses is challenging, so most research measures maternal exposure. Pregnancy induces a range of significant physiological changes in women that may affect chemical metabolism and responses. Moreover, placental function, fetal sex, and pregnancy complications may further modify these exposures. The purpose of this narrative review is to give an overview of major pregnancy-related physiological changes, including placental function and impacts of pregnancy complications, to summarize existing studies assessing chemical exposure in human fetal organs, and to discuss possible interactions between physiological changes and exposures. Our review reveals major knowledge gaps in factors affecting fetal chemical exposure, highlighting the need to develop more sophisticated tools for chemical health risk assessment in fetuses.

Bacteria metabolic adaptation to oxidative stress: the case of silica

Although the presence of silica in many living organisms offers advanced properties including cell protection, the different in vitro attempts to build living materials in pure silica never favoured the cells viability. Thus, little attention has been paid to host-guest interactions to modify the expected biologic response. Here we report the physiological changes undergone by Escherichia coli K-12 in silica from colloidal solution to gel confinement. We show that the physiological alterations in growing cultures are not triggered by the initial oxidative Reactive Oxygen Species (ROS) response. Silica promotes the induction of alternative metabolic pathways along with an increase of growth suggesting the existence of rpoS polymorphisms. Since the functionality of hybrid materials depends on the specific biologic responses of their guests, such cell physiological adaptation opens perspectives in the design of bioactive devices attracting for a large field of sciences.

Modeling Long-term Spike Frequency Adaptation in SA-I Afferent Neurons Using an Izhikevich-based Biological Neuron Model

To develop a biomimetic artificial tactile sensing system capable of detecting sustained mechanical touch, we propose a novel biological neuron model (BNM) for slowly adapting type I (SA-I) afferent neurons. The proposed BNM is designed by modifying the Izhikevich model to incorporate long-term spike frequency adaptation. Adjusting the parameters renders the Izhikevich model describing various neuronal firing patterns. We also search for optimal parameter values for the proposed BNM to describe firing patterns of biological SA-I afferent neurons in response to sustained pressure longer than 1-second. We obtain the firing data of SA-I afferent neurons for six different mechanical pressure ranging from 0.1 mN to 300 mN from the ex-vivo experiment on SA-I afferent neurons in rodents. Upon finding the optimal parameters, we generate spike trains using the proposed BNM and compare the resulting spike trains to those of biological SA-I afferent neurons using the spike distance metrics. We verify that the proposed BNM can generate spike trains showing long-term adaptation, which is not achievable by other conventional models. Our new model may offer an essential function to artificial tactile sensing technology to perceive sustained mechanical touch.

Rewetting the hyper-arid Atacama Desert soil reactivates a carbon-starved microbial decomposer community and also triggers archaeal metabolism

Extreme environmental conditions make soils of the hyper-arid Atacama Desert one of the most hostile habitats for life on the planet. During the short intervals of moisture availability that occur, it remains unresolved how soil microorganisms physiologically respond to such dramatic environmental changes. Therefore, we simulated a precipitation event - without (H₂O) and with (H₂O + C) labile carbon (C) supplementation - and investigated the responses in microbial communities (using phospholipid fatty acids (PLFAs) and archaeal glycerol dialkyl glycerol tetraether (GDGTs)) and physiology (by means of respiration, bacterial and fungal growth and C-use efficiency (CUE)) during a five-day incubation. We demonstrated that bacterial and fungal growth does occur in these extreme soils following rewetting, albeit at 100-10,000-fold lower rates compared to previously studied soil systems. C supplementation increased levels of bacterial growth and respiration responses by 5- and 50-fold, respectively, demonstrating a C-limited microbial decomposer community. While the microbial CUE following rewetting was c. 14 %, the addition of labile C during rewetting resulted in a substantial reduction (c. 1.6 %). Consistent with these interpretations, the PLFA composition clearly shifted from saturated towards more unsaturated and branched PLFAs, which could arise from (i) a physiological adaptation of the cell membrane to changing osmotic conditions or (ii) a community composition shift. Significant increases in total PLFA concentrations were solely found with H₂O + C addition. Contrary to other recent studies, we found evidence for a metabolically active archaeal community in these hyper-arid soils upon rewetting. We conclude that (i) microorganisms in this extreme soil habitat can be activated and grow within days following rewetting, (ii) available C is the limiting factor for microbial growth and biomass gains, and (iii) that an optimization of tolerating the extreme conditions while maintaining a high CUE comes at the expense of very poor resource-use efficiency during high resource availability.

Blood cells and hematological parameters of Chiala Mountain Salamander, Batrachuperus karlschmidti (Urodela, Hynobiidae)

Hematological parameters are essential indices for assessing the function of blood and reflecting not only the health status of animal but also their physiological adaptation to the environment. Herein, the composition of blood cells and the hematological parameters of wild Batrachuperus karlschmidti were examined for the first time, and the effects of sex, body size, body mass, and age on the hematological parameters were explored. The morphology and morphometric data of the blood cells, as well as the hematological parameters, of B. karlschmidti were slightly differ from those of its congener. However, hematological differences between sexes were only found in erythrocyte and leukocyte count, and mean cell volume (MCV), which possibly reflecting the need for better oxygen distribution and stronger immune protection for reproduction. Hematocrit (Hct) and mean cell hemoglobin (MCH) were strongly dependent on body mass. These also might have been attributed to higher oxygen requirements with larger body masses. This is a pilot project exploring the hematology of this species that may help establish hematological parameters in future for supporting species protection and monitoring studies, as well as help understanding the physiological adaptation of this species.

Effects of weather and social factors on hormone levels in the European badger (Meles meles)

Animals in the wild continually experience changes in environmental and social conditions, which they respond to with behavioural, physiological and morphological adaptations related to individual phenotypic quality. During unfavourable environmental conditions, reproduction can be traded-off against self-maintenance, mediated through changes in reproductive hormone levels. Using the European badger (Meles meles) as a model species, we examine how testosterone in males and oestrogens in females respond to marked deviations in weather from the long-term mean (rainfall and temperature, where badger earthworm food supply is weather dependent), and to social factors (number of adult males and females per social group and total adults in the population), in relation to age, weight and head-body length. Across seasons, testosterone levels correlated postively with body weight and rainfall variability, whereas oestrone correlated positively with population density, but negatively with temperature variability. Restricting analyses to the mating season (spring), heavier males had higher testosterone levels and longer females had higher oestradiol levels. Spring oestrone levels were lower when temperatures were above normal. That we see these effects for this generally adaptive species with a broad bioclimatic niche serves to highlight that climatic effects (especially with the threat of anthropogenic climate change) on reproductive physiology warrant careful attention in a conservation context.

The factors that influence the adaptation process 6 months after a stroke: A path analysis

OBJECTIVE

The purpose of this study was to identify the determinant factors that influence the adaptation process and quality of life after a stroke.

METHODS

This study is an observational study using a cross-sectional design. Respondents were patients who were 6 months post-discharge after non-hemorrhagic strokae and their family caregivers. Information about respondents was taken from medical record data at two regional general hospitals in West Kalimantan Province, Indonesia. A total of 80 patients were selected using a consecutive sampling method. Theoretical models of patient and caregiver factors that influence adaptation responses and post-stroke quality of life were tested using path analysis.

RESULT

Caregiver coping, self-efficacy, and illness acceptance had a direct effect on the post-stroke psychosocial adaptation response by 58.1%, with self-efficacy contributing the most (β = 0.668, P < .0001). Self-efficacy, illness acceptance, and healthy behavior had a direct effect on the physiological adaptation response by 24.3%, where self-efficacy also contributed the most (β = 0.272, P < .014). Psychosocial adaptation and physiological adaptation had a direct effect on the quality of life by 54.6%, where psychosocial adaptation showed the largest contribution (β = 0.63, P < .0001).

CONCLUSION

Self-efficacy contributes the most to both psychosocial and physiological adaptations 6 months after stroke. Psychosocial adaptation and self-efficacy have been proven to be the determinant factors that contribute the most to the quality of life of patients 6 months after stroke.

The efficacy of Azotobacter chroococcum in altering maize plant-defense responses to armyworm at elevated CO2 concentration

Elevated atmospheric carbon dioxide (eCO₂) concentrations can alter the carbon:nitrogen ratio and palatability of host plants for herbivorous insects, but rhizobacteria likely mitigate the alteration and influence physiological adaptation of insects. In this study, we conducted transcriptomic analysis of maize (Zea mays) response to Azotobacter chroococcum (AC) inoculation under eCO₂ conditions in contrast to ambient CO₂ (aCO₂), and studied the effects of plant-defense change of maize under eCO₂ on the oriental armyworm, Mythimna separata. Results showed that there were 16, 14, 16 and 135 differentially expressed genes that were associated with plant-defense response in maize leaves between aCO₂-CK and aCO₂-AC, eCO₂-CK and eCO₂-AC, aCO₂-CK and eCO₂-CK, aCO₂-AC and eCO₂-AC, respectively. Moreover, A. chroococcum inoculation and eCO₂ influenced plant hormone signal transduction of maize. Interestingly, A. chroococcum inoculation significantly decreased the contents of JA (jasmonic acid) and JA-Ile (isoleucine conjugate of JA) in leaves, but eCO₂ markedly increased contents of JA-Ile, JA and SA (salicylic acid). Compared to aCO₂, eCO₂ significantly decreased activity of protective enzyme (catalase), and increased activities of digestive (lipase and protease), protective (peroxidase) and detoxifying enzymes (carboxylesterase, Mixed-functional oxidase and glutathione s-transferase), prolonged developmental time, and decreased survival rate and body weight of larvae (P < 0.05). A. chroococcum inoculation significantly increased the activity of protective enzyme (catalase), and decreased the activities of detoxifying enzymes (carboxylesterase, glutathione s-transferase and mixed-functional oxidase), thus increased the growth rate and body weight of larvae in comparison with no-inoculation of A. chroococcum (P < 0.05). The indices of M. separata were significantly correlated with the foliar contents of JA, JA-Ile and SA (|r| = 0.44-0.85, P < 0.05), indicating that A. chroococcum inoculation altered the physiological adaptation of M. separata under eCO₂ by disturbing defense substances in maize. Our results in understanding effects of A. chroococcum inoculation on maize resistance to herbivorous insects will be valuable for agricultural pest control in the future at eCO₂ conditions.

Adaptive resilience of roadside trees to vehicular emissions via leaf enzymatic, physiological, and anatomical trait modulations

Unplanned urbanization and heavy automobile use by the rapidly growing population contribute to a variety of environmental issues. Roadside plants can mitigate air pollution by modifying their enzymatic activity, physiological and anatomical traits. Plant enzymes, physiological and anatomical traits play an important role in adaptation and mitigation mechanisms against vehicular emissions. There is a significant gap in understanding of how plant enzymes and anatomical traits respond or how they participate in modulating the effect of vehicular emissions/air pollution. Modulation of leaf anatomical traits is also useful in regulating plant physiological behavior. Hence, the present study was conducted to evaluate the effects of vehicular pollution on the enzymatic activity, physiological, and anatomical traits of plant species that grow in forests (S1) and alongside roads (S2-1 km away from the S1 site) during different seasons. The present study examines four commonly found roadside tree species i.e. Grevillea robusta, Cassia fistula, Quercus leucotrichophora and Cornus oblonga. The study found that the activities of catalase and phenylalanine ammonium enzymes were higher in G. robusta species of roadside than control site (S1). Non-enzymatic antioxidants such as flavonoid and phenol were also found in higher concentrations in roadside tree species during the summer season. However, the measured values of physiological traits were higher in Q. leucotrichophora tree species of S1 during the summer season. When compared to the other species along the roadside, Q. leucotrichophora had the highest number of stomata and epidermal cells during the summer season. Hence, we found that tree species grown along the roadside adapted towards vehicular emissions by modulating their enzymatic, physiological, and anatomical traits to mitigate the effect of air pollution.

Contrasting nursery habitats promote variations in the bioenergetic condition of juvenile female red squat lobsters (Pleuroncodes monodon) of the Southern Pacific Ocean

The red squat lobster Pleuroncodes monodon is an important fishery resource in the Humboldt Current System (HCS). This decapod is exploited in two fishing units: (a) the northern fishing unit (NFU, from 26°S to 30°S) and (b) the southern fishing unit (SFU, from 32°S to 37°S), each of which have an adjacent nursery area that is the source of recruits to replace the exploited adult populations (in the NFU: off the coast of Coquimbo (28°S) and in the SFU: off the coast of Concepción (36°S)). Marked spatial differences in the environmental conditions of the NFU and SFU, and the biogeographic break that exists between these nursery areas (30°S) may promote changes in the bioenergetic condition of new P. monodon juveniles. To evaluate this, we analyzed the bioenergetic condition (measured as: body mass, lipids, proteins, glucose, and energy) of new juvenile females in the main nursery areas off the Chilean coast. The juvenile females from the SFU showed a higher body mass than those from the NFU. Consistently, the juvenile females from the SFU had a higher content of lipids, proteins, and glucose than those from the NFU, indicative of higher energy contents and a higher lipid/protein ratio in the south compared to the north. Considering the current overexploitation of this fishery resource in the HCS, it is essential to understand how the bioenergetic condition of juvenile females of P. monodon may vary in nursery areas at different latitudes in order to generate sustainable fishery management policies with an ecological approach, designed specifically to each fishing unit. Furthermore, identifying the latitudinal variations of these biochemical compounds in P. monodon juveniles can elucidate the geographic origin of red squat lobsters that present a "better bioenergetic condition" in the HCS, which may significantly benefit sustainable fishing certification processes.

Cardiovascular Diseases in Pregnancy - A Brief Overview

Even though, there have been many advances in maternal medical care and fertility treatments, the presence of cardiovascular disease has a significant impact on pregnancy. In pregnant women, several heart conditions, such as valvular heart disease, chronic hypertension, congenital heart defects and non-ischemic cardiomyopathies are linked to increased risk of fetal as well as maternal morbidity and mortality. To date, the management of the co-existing conditions of pregnancy and heart disease has been challenging. Therefore, in-depth information may be beneficial to tackle a difficult case scenario. Towards this end, this paper provides an overview of the recent updated knowledge of pregnancy-related cardiovascular diseases in women.

Regional differences in clonal Japanese knotweed revealed by chemometrics-linked attenuated total reflection Fourier-transform infrared spectroscopy

BACKGROUND

Japanese knotweed (R. japonica var japonica) is one of the world's 100 worst invasive species, causing crop losses, damage to infrastructure, and erosion of ecosystem services. In the UK, this species is an all-female clone, which spreads by vegetative reproduction. Despite this genetic continuity, Japanese knotweed can colonise a wide variety of environmental habitats. However, little is known about the phenotypic plasticity responsible for the ability of Japanese knotweed to invade and thrive in such diverse habitats. We have used attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy, in which the spectral fingerprint generated allows subtle differences in composition to be clearly visualized, to examine regional differences in clonal Japanese knotweed.

RESULTS

We have shown distinct differences in the spectral fingerprint region (1800-900 cm^- 1) of Japanese knotweed from three different regions in the UK that were sufficient to successfully identify plants from different geographical regions with high accuracy using support vector machine (SVM) chemometrics.

CONCLUSIONS

These differences were not correlated with environmental variations between regions, raising the possibility that epigenetic modifications may contribute to the phenotypic plasticity responsible for the ability of R. japonica to invade and thrive in such diverse habitats.

Is cancer a disease set up by cellular stress responses?

For several decades, the somatic mutation theory (SMT) has been the dominant paradigm on cancer research, leading to the textbook notion that cancer is fundamentally a genetic disease. However, recent discoveries indicate that mutations, including "oncogenic" ones, are widespread in normal somatic cells, suggesting that mutations may be necessary but not sufficient for cancer to develop. Indeed, a fundamental but as yet unanswered question is whether or not the first step in oncogenesis corresponds to a mutational event. On the other hand, for some time, it has been acknowledged the important role in cancer progression of molecular processes that participate in buffering cellular stress. However, their role is considered secondary or complementary to that of putative oncogenic mutations. Here we present and discuss evidence that cancer may have its origin in epigenetic processes associated with cellular adaptation to stressful conditions, and so it could be a direct consequence of stress-buffering mechanisms that allow cells with aberrant phenotypes (not necessarily associated with genetic mutations) to survive and propagate within the organism. We put forward the hypothesis that there would be an inverse correlation between the activation threshold of the cellular stress responses (CSRs) and the risk of cancer, so that species or individuals with low-threshold CSRs will display a higher incidence or risk of cancer.

Effects of temperature fluctuation on endocrine disturbance of grass carp Ctenopharyngodon idella under mercury chloride stress

Mercury (Hg) is considered to be one of the most toxic and ubiquitously distributed metals in the aquatic system. Meanwhile, the temperature increase of water bodies due to global climatic changes, may affect ecosystems through alterations of the metal properties or by affecting the susceptibility of organisms. To study the physiological stress of mercury chloride on grass carp Ctenopharyngodon idella at different temperatures, we investigated the effects of water temperature and/or mercury chloride (HgCl₂) on growth performance (SGR-the specific growth rate, HSI-hepato-somatic index, CF-condition factor) and the thyroid hormones levels (T3-triiodothyronine; T4-thyroxine), as well as the expression levels of related genes involved growth and hypothalamus-pituitary-thyroid (HPT) axis. Fish (45.37 ± 3.58 g) were acclimated to 15, 20, 25, 30 or 35 °C and co-exposed to 0.0 or 0.039 mg/L HgCl₂ for 4 weeks in triplicates. Three-way ANOVA revealed that all variables were significantly affected by water temperature, HgCl₂ exposure, exposure time and their interactions. It was found that fish reared in Hg-free group at 25 °C showed the optimum growth. Otherwise, T4 concentrations were decreased, while T3 levels remained constant following exposure to HgCl₂, which was explained by the up-regulation of the dio2 gene. Our data provide evidences that increased temperatures can potentiate HgCl₂ toxicity, but the exact mechanism of the effects of temperature coupled HgCl₂ on fish is not full clear, which should be give more attention in future.

Autonomous climbing: An effective exercise mode with beneficial outcomes of aerobic exercise and resistance training

AIMS

To assess the effects of three specific exercise training modes, aerobic exercise (A), resistance training (R) and autonomous climbing (AC), aimed at proposing a cross-training method, on improving the physical, molecular and metabolic characteristics of mice without many side effects.

MATERIALS AND METHODS

Seven-week-old male mice were randomly divided into four groups: control (C), aerobic exercise (A), resistance training (R), and autonomous climbing (AC) groups. Physical changes in mice were tracked and analysed to explore the similarities and differences of these three exercise modes. Histochemistry, quantitative real-time PCR (RT-PCR), western blot (WB) and metabolomics analysis were performed to identify the underlying relationships among the three training modes.

KEY FINDINGS

Mice in the AC group showed better body weight control, glucose and energy homeostasis. Molecular markers of myogenesis, hypertrophy, antidegradation and mitochondrial function were highly expressed in the muscle of mice after autonomous climbing. The serum metabolomics landscape and enriched pathway comparison indicated that the aerobic oxidation pathway (pentose phosphate pathway, galactose metabolism and fatty acid degradation) and amino acid metabolism pathway (tyrosine, arginine and proline metabolism) were significantly enriched in group AC, suggesting an increased muscle mitochondrial function and protein balance ability of mice after autonomous climbing.

SIGNIFICANCE

We propose a new exercise mode, autonomous climbing, as a convenient but effective training method that combines the beneficial effects of aerobic exercise and resistance training.

Behavioural and biochemical alterations in gammarids as induced by chronic metallic exposures (Cd, Cu and Pb): Implications for freshwater biomonitoring

In freshwater species, metal toxicity is usually assessed through short-term exposures, hence limiting the practical usefulness of biomarkers for monitoring long-term impacts on wildlife populations. This study investigates the biological alterations elicited by chronic metallic exposures in Gammarus fossarum using multi-level biomarkers. In aquaria, gammarids were exposed for 10 weeks to field-realistic concentrations of Cd, Cu or Pb (0.25, 1.5 or 5.0 μg/L). At the individual level, behavioural traits (respiration, locomotion and feeding) were compared between naive and chronically-exposed gammarids. At the cellular level, enzymatic activities involved in digestion, moult and cell stress were monitored after 2, 6 and 10 weeks of exposure in males and females to consider the temporal feature of their responses. Results showed that the inhibitory effects of Cd and Pb on respiration and locomotion disappeared in chronically-exposed gammarids, reflecting acclimation to maintain these processes, unlike Cu. Chronic Cu- and Pb-elicited feeding inhibition was associated with the inhibitions of digestion enzymes. Chitobiase was inhibited by Cu in males and, by Cd and Pb in females, suggesting gender-dependent disturbances in moulting. In both genders, Cd generated cellular stress by stimulating acidic phosphatase and peroxidase activities. To conclude, such cellular impairments and alterations in individual performances are likely to disturb individual growth, population dynamics and litter decomposition in the long-term. Besides, obtaining biological responses, common to metals or specific to a metal or a gender, supports the development of biomarkers highlighting long-term impacts of metals on the health of organisms and their associated ecological functions in natural environments.

A Critical Review to Identify the Domains Used to Measure the Effect and Outcome of Adaptogenic Herbal Medicines

Background: Phytoadaptogens are considered to be herbal medicines with a multi-target effect that strengthen organ systems compromised by stress. Although animal and laboratory studies have identified numerous molecular targets associated with adaptogenic activity, the non-specific characteristic of these herbal medicines has meant there is no known methods to accurately determine efficacy of adaptogens in humans. This critical review of the evidence aims to identify domains which have been used to measure the effect of adaptogens in humans, in order to create pathways for translating laboratory, animal, and clinical studies on adaptogens into practical applications in the future. Methods: EMBASE, AMED, PubMed, Cochrane Library, and WHO ICTRP databases were searched for randomized trials which examined known physiological actions of adaptogens. Results: Twenty-four studies were identified and critically appraised using the Jadad scale. The findings identified three broad categories of outcome measures, including cognitive, mood and biological measures. Conclusions: There was a great heterogeneity in data making it difficult to draw conclusions as to the most effective measurement tools to capture the holistic activity in humans. Cognitive measures hold promise as a reliable measurement tool when used in conjunction with other relevant tools. Further investigation is necessary to determine the most appropriate and diverse tools to measure the complex multi-target action of adaptogens.

Adaptations to the mudflat: Insights from physiological and transcriptional responses to thermal stress in a burrowing bivalve Sinonovacula constricta

Understanding physiological adaptations of organisms to temperature changes that characterize their habitat is the first step in predicting the putative effects of global climate change on population dynamics. Mudflats are an important part of the intertidal zone and experience extreme and fluctuating temperatures. Therein, species would be potentially susceptible to global warming. The present study explored physiological adaptations of burrowing species to life in an intertidal mudflat by analyzing the potential operative temperatures in the mudflat, and assessing cardiac performance and the transcriptional response to thermal stress by a typical burrowing bivalve, the razor clam Sinonovacula constricta in different thermal environments, mimicking conditions during low tides. Clams showed higher thermal sublethal limits in mud with overlying air than in mud with overlying water, indicating an adaptation to rapidly changing ambient temperatures and thermal environments during emersion. This sublethal limit was far above the maximum operative temperature in the actual habitat site and suggests a potential buffer zone to ensure survival under unexpected high temperatures, that could occur with global warming. In response to high temperature, S. constricta exhibited the common heat stress response by up-regulating expression of the Bcl2-associated athanogene 3 (BAG3) and heat shock proteins to cope with the adverse effects of high temperature on protein homeostasis. Increased expression of key genes, including molybdenum cofactor synthesis 3 (MOCS3), oligoribonuclease (REX2), and NFκappaB inhibitor alpha (NFIA) may further remit the effect of thermal stress during the emersion period and delay a situation where clams reach their thermal sublethal limit, thereby helping to endure high temperature during low tide. These results clearly illustrate significant adaptations of a burrowing bivalve to life in intertidal mudflats at both physiological and molecular levels and can provide insights into potential physiological or evolutionary responses that could aid survival of mudflat species in a changing global climate.

Temperature-related heart rate in water and air and a comparison to other temperature-related measures of performance in the fiddler crab Leptuca pugilator (Bosc 1802)

Performance in poikilotherms is known to be sensitive to temperature, often with a low-sloping increase with temperature to a peak, and a steep decline with increasing temperature past the peak. We complemented past measures of performance by measuring heartbeat rates of the fiddler crab Leptuca pugilator in water and in air as a function of a range of temperatures previously shown to affect other measures of performance. In water over a range of 20-50 °C, heartbeat increased steadily to a peak at 40 °C and then steeply declined to near zero at 50 °C. In air, heartbeat also increased, but to a peak at 35 °C and then with a gentler decline than was found in water. Part of this different response may be due to evaporative water loss, which reduced body temperature in air, and therefore thermal stress, relative to body temperature when crabs were immersed in water. Increased availability of oxygen from air, according to the oxygen and capacity-limited thermal tolerance hypothesis, likely increased aerobic scope past the thermal peak, relative to within water, where oxygen delivery at higher temperatures may have been curtailed. We compared the heart rate performance relations to two previous measures of performance - endurance on a treadmill and sprint speed, both done in air. The peak performance temperature increased in the order: treadmill endurance time, sprint speed, heart rate in air, and heart rate in water, which demonstrates that different performance measures give different perspectives on the relation of thermal tolerance and fitness to temperature. Endurance may therefore be the limiting upper thermal stress factor in male fiddler crabs, when on hot sand flats. Temperature preference, found to be for temperatures <30 °C in air, could be a bet-hedging evolutionary strategy to avoid aerobic scope affecting endurance.

A quantitative method for estimating the adaptedness in a physiological study

Background

Existed mathematical models of individual adaptation are mostly reductionist by nature. Researchers usually a priori consider the subject adapted basing only on the fact of continued or prolonged influence of the harmful factor. This paper describes a method that allows assessing the physiological adaptedness to experimental challenges on the basis of holistic approach and quantitative criteria.

Methods

The suggested method comprises simple equations and incorporates into the model an indicator that differentiates functions in regard to their significance for determining physiological adaptedness considered as an outcome of the adaptive process.

Results

The proposed empirical model affords the possibility of comparing subjects in respect to their resistance to several loads. Physiological parameters were differentiated with regard to their significance for assessing adaptedness. Two examples of animal adaptation to exercise after physical training and plant adaptogen administration are considered.

Conclusion

The calculated index of adaptedness is useful in that it replaces wordy descriptions of large tables that reveal alterations in numerous parameters of many subjects under study.

Genetic, epigenetic, and developmental toxicity of Chironomus riparius raised in metal-contaminated field sediments: A multi-generational study with arsenic as a second challenge

Ecotoxicity tests conducted under well-controlled lab conditions often do not reflect the real environmental conditions. To this end, we designed an ecotoxicity test using an aquatic midge, Chironomus riparius, raised in metal-contaminated field sediments (MCFS), which reflect the real environmental conditions, for five consecutive generations (F0-F4) followed by a toxic response to arsenic exposure (as a second challenge). The toxic responses (i.e. DNA damage, DNA methylation, stress response gene expression, and mortality) were compared to those organisms reared in lab sediments (LS). Under the MCFS condition, increased adult emergence was observed for the second and third generations (F1 and F2), while a decreased tendency was evident thereafter (F3 and F4) compared to that of F0. When comparing C. riparius raised in MCFS or LS exposed to arsenic, increased sensitivity (declined survival) was observed in the larvae from F2. However, that tendency was not present in F4 of the MCFS midges, indicating a possible physiological adaptation. Increased DNA damage was observed in the MCFS-exposed organisms (F0, F2, and F4) compared to the those exposed to LS, particularly at F0. Arsenic exposure induced hypermethylation at F0 and, in contrast, hypomethylation at the later generations (F2, F4) in the MCFS-exposed organisms. Global DNA methylation results were supported by the expression of genes involved in enzymatic methylation. Moreover, alterations in oxidative stress related to gene expression showed that significant oxidative stress and perturbation of glutathione reserves occurred under the MCFS and the subsequent arsenic exposure conditions. Overall, our results suggest that multigenerational rearing under MCFS conditions resulted in physiological adaptation of C. riparius to metal exposure, specifically at later generations, which in turn modulated its response to arsenic stress through possible genetic and epigenetic mechanisms.

The Breast Feeding Adaptation Scale-Short Form: Development and Testing of Its Psychometric Properties and Measurement Invariance

PURPOSE

This study sought to develop the Breastfeeding Adaptation Scale-Short Form(BFAS-SF) for use at 4 weeks postpartum, to test its validity and reliability, and to examine its measurement invariance. The latent mean score of the BFAS-SF across multiple groups was also compared.

METHODS

This methodological research study was conducted to develop a short form of the BFAS and to test its psychometric properties and measurement invariance. Data were collected twice for measurement invariance testing. The sample included 431 and 272 breastfeeding mothers at 2 weeks and 4 weeks postpartum, respectively.

RESULTS

Confirmatory factor analysis supported six dimensions of the BFAS-SF at 4 weeks postpartum. Multi-group confirmatory factor analysis revealed evidence for invariance of the BFAS-SF according to employment status, parity, delivery mode, and the postpartum period. There were statistically significant latent mean differences. Mothers who were unemployed and who had a vaginal delivery showed significantly higher scores for breastfeeding confidence, sufficient breast milk, and baby's satisfaction with breastfeeding.

CONCLUSION

The BFAS-SF is valid, reliable, and an appropriate instrument for assessing mothers' breastfeeding adaptation. It can be used to compare mean scores according to employment status and delivery mode.

Multi-generational impacts of organic contaminated stream water on Daphnia magna: A combined proteomics, epigenetics and ecotoxicity approach

The present study aimed to elucidate the mechanisms of organismal sensitivity and/or physiological adaptation in the contaminated water environment. Multigenerational cultures (F0, F1, F2) of Daphnia magna in collected stream water (OCSW), contaminated with high fecal coliform, altered the reproductive scenario (changes in first brood size timing, clutch numbers, clutch size etc.), compromised fitness (increase hemoglobin, alteration in behavior), and affected global DNA methylation (hypermethylation) without affecting survival. Using proteomics approach, we found 288 proteins in F0 and 139 proteins in F2 that were significantly differentially upregulated after OCSW exposure. The individual protein expressions, biological processes and molecular functions were mainly related to metabolic processes, development and reproduction, transport (protein/lipid/oxygen), antioxidant activity, increased globin and S-adenosylmethionine synthase protein level etc., which was further found to be connected to phenotype-dependent endpoints. The proteomics pathway analysis evoked proteasome, chaperone family proteins, neuronal disease pathways (such as, Parkinson's disease) and apoptosis signaling pathways in OCSW-F0, which might be the cause of behavioral and developmental alterations in OCSW-F0. Finally, chronic multigenerational exposure to OCSW exhibited slow physiological adaptation in most of the measured effects, including proteomics analysis, from the F0 to F2 generations. The common upregulated proteins in both generations (F0 & F2), such as, globin, vitellinogen, lipid transport proteins etc., were possibly play the pivotal role in the organism's physiological adaptation. Taken together, our results, obtained with a multilevel approach, provide new insight of the molecular mechanism in fecal coliform-induced phenotypic plasticity in Daphnia magna.

A data-driven model to study utero-ovarian blood flow physiology during pregnancy

In this paper, we describe a mathematical model of the cardiovascular system in human pregnancy. An automated, closed-loop 1D-0D modelling framework was developed, and we demonstrate its efficacy in (1) reproducing measured multi-variate cardiovascular variables (pulse pressure, total peripheral resistance and cardiac output) and (2) providing automated estimates of variables that have not been measured (uterine arterial and venous blood flow, pulse wave velocity, pulsatility index). This is the first model capable of estimating volumetric blood flow to the uterus via the utero-ovarian communicating arteries. It is also the first model capable of capturing wave propagation phenomena in the utero-ovarian circulation, which are important for the accurate estimation of arterial stiffness in contemporary obstetric practice. The model will provide a basis for future studies aiming to elucidate the physiological mechanisms underlying the dynamic properties (changing shapes) of vascular flow waveforms that are observed with advancing gestation. This in turn will facilitate the development of methods for the earlier detection of pathologies that have an influence on vascular structure and behaviour.

Mouse incising central pattern generator: Characteristics and modulation by pain

INTRODUCTION

Vertebrate incising and chewing are controlled by a set of neurons comprising the central pattern generator (CPG) for mastication. Mandibular positioning and force generation to perform these tasks is complex and requires coordination of multiple jaw opening and closing muscle compartments located in muscles on both sides of the jaw. The purpose of this study was to determine the characteristics of the CPG by recording mouse incising forces in the home cage environment to evaluate changes in force characteristics with incising frequency and force direction. A second purpose was to evaluate the effects of jaw closing muscle pain on CPG output parameters.

METHODS

Digitized incising forces were recorded for approximately 24 h using a 3-dimensional force transducer attached to solid food chow. Male and female CD-1 mice were evaluated during their last (fourth) baseline assessment and seven days after a second acidic saline injection into the left masseter muscle when maximum pain was experienced. Incising force resultants were calculated from the three axes data and force parameters were assessed including inter-peak intervals (IPI), peak amplitude, load time and unload time. Multiple regression analyses were conducted to identify incising episodes that had parameters of force that were significantly correlated (p < 0.001). These incising episodes were considered to represent the output of the CPG with a steady state of incoming sensory afferent inputs. Incising parameters were evaluated for each of the discrete incising frequencies (4.6, 5.3, 6.2, 7.6 Hz) and the predominant force directions: jaw closing (-Z), jaw retrusion (+X) and jaw protrusion (-X).

RESULTS

A significant correlation between incising frequency (IPI) and the load time was observed. A significant decrease in peak amplitude was observed with higher incising frequency while the load rate significantly increased. The force peak amplitude and load rates were found to be statistically different when the force direction was considered, with smaller peak amplitudes and smaller load rates found in the jaw closing direction. The effect of pain on incising was to reduce the peak amplitude and load rate of incising compared to the baseline condition at lower incising frequencies.

CONCLUSIONS

Like the central pattern generator for locomotion, the CPG for incising controls rhythmicity, peak amplitude and force load duration/rate. However, unlike the CPG for locomotion, the amplitude of incising force decreases as the frequency increases. During incising, load rate increases with faster rhythm and is consistent with the recruitment of larger motor units. Muscle pain reduced the excitatory drive of the CPG on motoneurons and provides further support of the Pain Adaptation Model.

Growth, physiological adaptation, and NHX gene expression analysis of Iris halophila under salt stress

This study investigated the growth, physiological changes, and the transcript levels of NHX1 gene of Iris halophila in response to low NaCl concentration (50 mM) and high NaCl concentration (150 mM). Our results showed that both 50 and 150 mM NaCl had no obvious negative effects on plant growth; what is more, low NaCl concentration (50 mM) increased root length, root fresh weight, and the ratio of root length to leaf length compared with the control group. The malondialdehyde (MDA) contents in leaves and roots of I. halophila had no obvious difference as compared with control. Proline levels of I. halophila exhibited basically an enhancement under salt stress conditions. Particularly at 4 days, the proline contents in leaves reached 1.85 to 2.31-fold higher and the contents in roots reached 1.27 to 1.62-fold higher than that of control at 50 and 150 mM NaCl, respectively. The contents of the soluble sugar in leaves and roots of I. halophila under 150 mM NaCl at 7 days were 32.4 and 98.7% higher than that of control, respectively. The increase rate of K⁺ contents with the increasing concentration of salt was less than that of Na⁺ contents, but K⁺ contents in the seedlings under NaCl stress was still higher than Na⁺ contents and the ratio of K⁺ to Na⁺ was also greater than 1. The transcript levels of IhNHX1 in leaves of I. halophila at 4 and 7 days under 150 mM NaCl were higher than that of control; however, the transcript levels of IhNHX1 in roots had no significant difference compared with the control under low and high salt stress at 1, 4, and 7 days. Therefore, salt tolerance in I. halophila could be partially due to higher proline, soluble sugar, and K⁺ accumulation.

Androgenic-anabolic steroids inhibited post-exercise hypotension: a case control study

BACKGROUND

There is evidence of hypertensive effects caused by anabolic androgenic steroids (AAS). A single exercise session promotes the acute reduction of blood pressure, but the effects of AAS on this phenomenon are unknown.

OBJECTIVES

To investigate the post-exercise blood pressure response in androgenic-anabolic steroid users.

METHODS

Thirteen AAS users (23.9±4.3 years old) and sixteen controls (22.1±4.5 years old) performed a session of aerobic exercise. Heart rate and blood pressure were assessed before exercise and during a 60min post-exercise resting period. Repeated ANOVA measures were used to determine differences between the groups.

RESULTS

While the control group had a significant reduction in post-exercise systolic blood pressure of up to 13.9±11.6mmHg at 40min, this phenomenon was limited among AAS users who reached a maximum of 6.2±11.5mmHg at 60min. The between groups comparison revealed significant higher post-exercise hypotension (PEH) for the control group at 30min (-12.9±14.1mmHg versus -2.9±7.6mmHg), 40min (-13.9±11.6mmHg versus -2.5±8.3mmHg), 50min (-13.9±13.9mmHg versus -5.0±7.9mmHg) and 60min (-12.5±12.8mmHg versus -6.2±11.5mmHg). There was no significant diastolic PEH in any of the groups.

CONCLUSIONS

This study demonstrated impaired systolic post-exercise hypotension as a new adverse effect of AAS usage.

The Humboldt Penguin (Spheniscus humboldti) Rete Tibiotarsale - A supreme biological heat exchanger

Humans are unable to survive low temperature environments without custom designed clothing and support systems. In contrast, certain penguin species inhabit extremely cold climates without losing substantial energy to self-heating (emperor penguins ambient temperature plummets to as low as -45°C). Penguins accomplish this task by relying on distinct anatomical, physiological and behavioral adaptations. One such adaptation is a blood vessel heat exchanger called the 'Rete Tibiotarsale' - an intermingled network of arteries and veins found in penguins' legs. The Rete existence results in blood occupying the foot expressing a lower average temperature and thus the penguin loosing less heat to the ground. This study examines the Rete significance for the species thermal endurance. The penguin anatomy (leg and main blood vessels) is reconstructed using data chiefly based on the Humboldt species. The resulting model is thermally analyzed using finite element (COMSOL) with the species environment used as boundary conditions. A human-like blood vessel configuration, scaled to the penguin's dimensions, is used as a control for the study. Results indicate that the Rete existence facilitates upkeep of 25-65% of the species total metabolic energy production as compared with the human-like configuration; thus making the Rete probably crucial for penguin thermal endurance. Here, we quantitatively link for the first time the function and structure of this remarkable physiological phenotype.

The human physiological impact of global deoxygenation

There has been a clear decline in the volume of oxygen in Earth’s atmosphere over the past 20 years. Although the magnitude of this decrease appears small compared to the amount of oxygen in the atmosphere, it is difficult to predict how this process may evolve, due to the brevity of the collected records. A recently proposed model predicts a non-linear decay, which would result in an increasingly rapid fall-off in atmospheric oxygen concentration, with potentially devastating consequences for human health. We discuss the impact that global deoxygenation, over hundreds of generations, might have on human physiology. Exploring the changes between different native high-altitude populations provides a paradigm of how humans might tolerate worsening hypoxia over time. Using this model of atmospheric change, we predict that humans may continue to survive in an unprotected atmosphere for ~3600 years. Accordingly, without dramatic changes to the way in which we interact with our planet, humans may lose their dominance on Earth during the next few millennia.

Hemoglobin-oxygen affinity in high-altitude vertebrates: is there evidence for an adaptive trend?

In air-breathing vertebrates at high altitude, fine-tuned adjustments in hemoglobin (Hb)-O2 affinity provide an energetically efficient means of mitigating the effects of arterial hypoxemia. However, it is not always clear whether an increased or decreased Hb-O2 affinity should be expected to improve tissue O2 delivery under different degrees of hypoxia, due to the inherent trade-off between arterial O2 loading and peripheral O2 unloading. Theoretical results indicate that the optimal Hb-O2 affinity varies as a non-linear function of environmental O2 availability, and the threshold elevation at which an increased Hb-O2 affinity becomes advantageous depends on the magnitude of diffusion limitation (the extent to which O2 equilibration at the blood-gas interface is limited by the kinetics of O2 exchange). This body of theory provides a framework for interpreting the possible adaptive significance of evolved changes in Hb-O2 affinity in vertebrates that have colonized high-altitude environments. To evaluate the evidence for an empirical generalization and to test theoretical predictions, I synthesized comparative data in a phylogenetic framework to assess the strength of the relationship between Hb-O2 affinity and native elevation in mammals and birds. Evidence for a general trend in mammals is equivocal, but there is a remarkably strong positive relationship between Hb-O2 affinity and native elevation in birds. Evolved changes in Hb function in high-altitude birds provide one of the most compelling examples of convergent biochemical adaptation in vertebrates.

Does physiological response to disease incur cost to reproductive ecology in a sexually dichromatic amphibian species?

It is well known that the disease chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) has contributed to amphibian declines worldwide. The impact of Bd varies, with some species being more susceptible to infection than others. Recent evidence has shown that Bd can have sub-lethal effects, whereby increases in stress hormones have been associated with infection. Could this increased stress response, which is a physiological adaptation that provides an increased resilience against Bd infection, potentially be a trade-off with important life-history traits such as reproduction? We studied this question in adult male frogs of a non-declining species (Litoria wilcoxii). Frogs were sampled for (1) seasonal hormone (testosterone and corticosterone), color and disease profiles, (2) the relationship between disease infection status and hormone levels or dorsal color, (3) subclinical effects of Bd by investigating disease load and hormone level, and (4) reproductive and stress hormone relationships independent of disease. Testosterone levels and color score varied seasonally (throughout the spring/summer months) while corticosterone levels remained stable. Frogs with high Bd prevalence had significantly higher corticosterone levels and lower testosterone levels compared to uninfected frogs, and no differences in color were observed. There was a significant positive correlation between disease load and corticosterone levels, and a significant negative relationship between disease load and testosterone. Our field data provides novel evidence that increased physiological stress response associated with Bd infection in wild frogs, could suppress reproduction by down-regulating gonadal hormones in amphibians, however the impacts on reproductive output is yet to be established.

Brown adipose tissue thermogenesis does not explain the intra-administration hyperthermic sign-reversal induced by serial administrations of 60% nitrous oxide to rats

Initial administration of ≥60% nitrous oxide (N2O) to rats promotes hypothermia primarily by increasing whole-body heat loss. We hypothesized that the drug promotes heat loss via the tail and might initially inhibit thermogenesis via brown adipose tissue (BAT), major organs of thermoregulation in rodents. Following repeated administrations, N2O inhalation evokes hyperthermia underlain by increased whole-body heat production. We hypothesized that elevated BAT thermogenesis plays a role in this thermoregulatory sign reversal. Using dual probe telemetric temperature implants and infrared (IR) thermography, we assessed the effects of nine repeated 60% N2O administrations compared to control (con) administrations on core temperature, BAT temperature, lumbar back temperature and tail temperature. Telemetric core temperature, telemetric BAT temperature, and IR BAT temperature were reduced significantly during initial 60% N2O inhalation (p≤0.001 compared to con). IR thermography revealed that acute N2O administration unexpectedly reduced tail temperature (p=0.0001) and also inhibited IR lumbar temperature (p<0.0001). In the 9th session, N2O inhalation significantly increased telemetric core temperature (p=0.007) indicative of a hyperthermic sign reversal, yet compared to control administrations, telemetric BAT temperature (p=0.86), IR BAT temperature (p=0.85) and tail temperature (p=0.47) did not differ significantly. Thus, an initial administration of 60% N2O at 21°C may promote hypothermia via reduced BAT thermogenesis accompanied by tail vasoconstriction as a compensatory mechanism to limit body heat loss. Following repeated N2O administrations rats exhibit a hyperthermic core temperature but a normalized BAT temperature, suggesting induction of a hyperthermia-promoting thermogenic adaptation of unknown origin.

Physiological adaptation of growth kinetics in activated sludge

Physiological adaptation as it occurs in bacterial cells at variable environmental conditions influences characteristic properties of growth kinetics significantly. However, physiological adaptation to growth related parameters in activated sludge modelling is not yet recognised. Consequently these parameters are regarded to be constant. To investigate physiological adaptation in activated sludge the endogenous respiration in an aerobic degradation batch experiment and simultaneous to that the maximum possible respiration in an aerobic growth batch experiment was measured. The activated sludge samples were taken from full scale wastewater treatment plants with different sludge retention times (SRTs). It could be shown that the low SRT sludge adapts by growth optimisation (high maximum growth rate and high decay rate) to its particular environment where a high SRT sludge adapts by survival optimization (low maximum growth rate and low decay rate). Thereby, both the maximum specific growth rate and the decay rate vary in the same pattern and are strongly correlated to each other. To describe the physiological state of mixed cultures like activated sludge quantitatively a physiological state factor (PSF) is proposed as the ratio of the maximum specific growth rate and the decay rate. The PSF can be expressed as an exponential function with respect to the SRT.

Assessing adaptability and reactive scope: Introducing a new measure and illustrating its use through a case study of environmental stress in forest-living baboons

In order to maintain regulatory processes, animals are expected to be adapted to the range of environmental stressors usually encountered in their environmental niche. The available capacity of their stress responses is termed their reactive scope, which is utilised to a greater or lesser extent to deal with different stressors. Typically, non-invasive hormone assessment is used to measure the physiological stress responses of wild animals, but, for methodological reasons, such measurements are not directly comparable across studies, limiting interpretation. To overcome this constraint, we propose a new measure of the relative strength of stress responses, 'demonstrated reactive scope', and illustrate its use in a study of ecological correlates (climate, food availability) of faecal glucocorticoid (fGC) levels in two forest-living troops of baboons. Results suggest the wild-feeding troop experiences both thermoregulatory and nutritional stress, while the crop-raiding troop experiences only thermoregulatory stress. This difference, together with the crop-raiding troop's lower overall physiological stress levels and lower demonstrated fGC reactive scope, may reflect nutritional stress-buffering in this troop. The relatively high demonstrated fGC reactive scope levels of both troops compared with other baboons and primate species, may reflect their extreme habitat, on the edge of the geographic range for baboons. Demonstrated reactive scope provides a means of gauging the relative strengths of stress responses of individuals, populations, or species under different conditions, enhancing the interpretive capacity of non-invasive studies of stress hormone levels in wild populations, e.g. in terms of animals' adaptive flexibility, the magnitude of their response to anthropogenic change, or the severity of impact of environmental conditions.