Physiological Limits Research Articles

KiNext: a portable and scalable workflow for the identification and classification of protein kinases

BackgroundProtein kinases are a diverse superfamily of proteins common to organisms across the tree of life that are typically involved in signal transduction, allowing organisms to sense and respond to biotic or abiotic environmental factors. They have important roles in organismal physiology, including development, reproduction, acclimation to environmental stress, while their dysregulation can lead to disease, including several forms of cancer. Identifying the complement of protein kinases (the kinome) of any organism is useful for understanding its physiological capabilities, limitations and adaptations to environmental stress. The increasing availability of genomes makes it now possible to examine and compare the kinomes across a broad diversity of organisms. Here we present a pipeline respecting the FAIR principles (findable, accessible, interoperable and reusable) that facilitates the search and identification of protein kinases from a predicted proteome, and classifies them according to group of serine/threonine/tyrosine protein kinases present in eukaryotes.ResultsKiNext is a Nextflow pipeline that regroups a number of existing bioinformatic tools to search for and classify the protein kinases of an organism in a reproducible manner, starting from a set of amino acid sequences. Conventional eukaryotic protein kinases (ePKs) and atypical protein kinases (aPKs) are identified by using Hidden Markov Models (HMMs) generated from the catalytic domains of kinases. Furthermore, KiNext categorizes ePKs into the eight kinase groups by employing dedicated Hidden Markov Models (HMMs) tailored for each group. The performance of the KiNext pipeline was validated against previously identified kinomes obtained with other tools that were already published for two marine species, the Pacific oyster Crassostrea gigas and the unicellular green alga Ostreoccocus tauri. KiNext outperformed previous results by finding previously unidentified kinases and by attributing a large proportion of previously unclassified kinases to a group in both species. These results demonstrate improvements in kinase identification and classification, all while providing traceability and reproducibility of results in a FAIR pipeline. The default HMM models provided with KiNext are most suitable for eukaryotes, but the pipeline can be easily modified to include HMM models for other taxa of interest.ConclusionThe KiNext pipeline enables efficient and reproducible identification of kinomes based on predicted amino acid sequences (i.e. proteomes). KiNext was designed to be easy to use, automated, portable and scalable.

Methodological aspects of correlative, multimodal, multiparametric breast cancer imaging: from data acquisition to image processing for AI-based radioproteomics in a preclinical setting

Preclinical high-field magnetic resonance imaging (MRI) systems offer a diverse array of MRI techniques, providing rich multiparametric MRI (mpMRI) platforms for studying numerous biological parameters. mpMRI platforms prove particularly indispensable when investigating tumors that exhibit profound intratumoral heterogeneity, such as breast cancer. A thoughtful comprehension of the origins of intratumoral heterogeneity is imperative for the judicious assessment of new targeted therapies and treatment interventions. Furthermore, when data from mpMRI are complemented with data from other in vivo imaging modalities, such as positron emission tomography (PET), and correlated with data from ex vivo modalities, such as matrix-assisted laser desorption imaging mass spectrometry (MALDI IMS), the in vivo parameters can be further elucidated at a molecular level and microscopic scale. Nevertheless, extracting meaningful scientific insights from such complex datasets necessitates the utilization of machine learning (ML) approaches to discern region-specific radiomic features. The development of correlative, multimodal imaging (CMI) workflows, such as one incorporating MRI, PET and MALDI IMS, is inherently challenging, given the many technological and methodological challenges related to multimodal data acquisition as well as the physiological limitations of the laboratory mice of the investigation. Standardization efforts in image acquisition and processing are required to increase the reproducibility and translatability of CMI data. To address the challenges of developing standardized CMI workflows and stimulate dialog regarding this area of need, we present a practical workflow to investigate tumor heterogeneity in breast cancer xenografts across various spatial scales. Our workflow entails simultaneous functional MRI and PET acquisitions in living mice, followed by correlation with post-imaging MALDI IMS and histologic data. Additionally, we propose data preprocessing steps for potential ML applications. We illustrate the feasibility of this workflow through two examples, showcasing its effectiveness in comparing in vivo and ex vivo images to evaluate tumor metabolism and hypoxia in mice with breast cancer xenografts.

Lower limb acute onset muscle pain: what do we have to look for? A case of isolated rupture of the rectus femoris.

Acute muscle pain is muscle soreness that occurs during or within 24 hours of strenuous activity. Possible causes of acute muscle pain include localized muscle trauma, muscle tear, contusion with acute hemorrhage, or acute compartment syndrome. Isolated ruptures of the rectus femoris muscle are rare clinical conditions that result from excessive muscle strain following an abrupt contraction, incorrect movement, or sudden snap that exceeds the physiological limit of strain that the muscle can withstand. To date, there are few published reports evaluating the results of non-invasive treatment of such injuries. Herein, we report an unusual case of isolated distal rectus femoris tear in a 46-year-old female patient with no risk factors, who initially presented with extensor muscle weakness and pain and was treated conservatively with functional rest, physiotherapy, and cryotherapy.

Between Life and Death: Sea Urchin Embryos Undergo Peculiar DNA Fragmentation after Exposure to Vanadium, Cadmium, Gadolinium, and Selenium.

Exogenous DNA damage represents one of the most harmful outcomes produced by environmental, physical, or chemical agents. Here, a comparative analysis of DNA fragmentation was carried out on Paracentrotus lividus sea urchin embryos exposed to four common pollutants of the marine environment: vanadium, cadmium, gadolinium and selenium. Using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, fragmented DNA was quantified and localized in apoptotic cells mapping whole-mount embryos. This is the first study reporting how different chemicals are able to activate distinctive apoptotic features in sea urchin embryos, categorized as follows: (i) cell-selective apoptosis, showing DNA fragmentation restricted to a subset of extremely damaged cells, acting as an embryo survival mechanism; or (ii) total apoptosis, with fragmented DNA widespread throughout the cells of the entire embryo, leading to its death. Also, this is the first report of the effects of Se exposure on P. lividus sea urchin embryos. These data confirm the TUNEL assay as the most suitable test to study DNA fragmentation in the sea urchin embryo model system. Taken together, this research highlights embryos' ability to find alternative pathways and set physiological limits for development under stress conditions.

Directional Electron Transfer in Enzymatic Nano‐Bio Hybrids for Selective Photobiocatalytic Conversion of Nitrate

Semi‐artificial photosynthetic system (SAPS) that combines enzymes or cellular organisms with light‐absorbing semiconductors, has emerged as an attractive approach for nitrogen conversion, yet faces the challenge of reaction pathway regulation. Herein, we find that photoelectrons can transfer from the ‐C≡N groups at the edge of cyano‐rich carbon nitride (g‐C3N4‐CN) to nitrate reductase (NarGH), while the direct electron transfer to nitrite reductase (cd1NiR) is inhibited due to the physiological distance limit of active sites (> 14 Å). By means of the directional electron transfer between g‐C3N4‐CN and extracted biological enzymes, the product of the denitrification reaction was switched from inert N2 to usable nitrite with an unprecedented selectivity of up to 95.3%. The converted nitrite could be further utilized by anammox microbiota and dissimilatory nitrate reduction to ammonia (DNRA) microorganisms, doubling the efficiency of total nitrogen removal (96.5 ± 2.3 %) for biological nitrogen removal and ammonia generation (12.6 mg NH4+‐N L‐1 h‐1), respectively. Thus, our work paves an appealing way for the sustainable treatment and utilization of nitrate for ammonia fuel production by strategically regulating the electron transfer pathway across the biotic‐abiotic interface.

Directional Electron Transfer in Enzymatic Nano-Bio Hybrids for Selective Photobiocatalytic Conversion of Nitrate.

Semi-artificial photosynthetic system (SAPS) that combines enzymes or cellular organisms with light-absorbing semiconductors, has emerged as an attractive approach for nitrogen conversion, yet faces the challenge of reaction pathway regulation. Herein, we find that photoelectrons can transfer from the -C≡N groups at the edge of cyano-rich carbon nitride (g-C3N4-CN) to nitrate reductase (NarGH), while the direct electron transfer to nitrite reductase (cd1NiR) is inhibited due to the physiological distance limit of active sites (> 14 Å). By means of the directional electron transfer between g-C3N4-CN and extracted biological enzymes, the product of the denitrification reaction was switched from inert N2 to usable nitrite with an unprecedented selectivity of up to 95.3%. The converted nitrite could be further utilized by anammox microbiota and dissimilatory nitrate reduction to ammonia (DNRA) microorganisms, doubling the efficiency of total nitrogen removal (96.5 ± 2.3 %) for biological nitrogen removal and ammonia generation (12.6 mg NH4+-N L-1 h-1), respectively. Thus, our work paves an appealing way for the sustainable treatment and utilization of nitrate for ammonia fuel production by strategically regulating the electron transfer pathway across the biotic-abiotic interface.

The role of L-arginine as a donor of nitric oxide and the prospects for its use: the review

The article discusses recent research on the effective and safe use of the amino acid L-arginine for medicinal purposes in various pathologies. The practical significance of using L-arginine as a source of nitric oxide is considered. The physiological role of nitric oxide, the main vasodilator, was shown, and its deficiency was found to be a key link in endothelial dysfunction. An analysis of modern studies confirming the effectiveness of L-arginine as a donor of nitric oxide was carried out. Ample evidence suggests that oral administration of L-arginine, within physiological limits, can benefit human health by increasing NO synthesis and hence tissue blood flow.

Zinc Nano and Zinc Ethylenediaminetetraacetic acid (EDTA) Mediated Water Deficit Stress Alleviation in Pearl Millet (Pennisetum glaucum (L.) R. Br.): Photosystem II Electron Transport and Pigment Dynamics

Water stress adversely affects the photosynthetic apparatus and pigment composition in plants, leading to reduced yields and compromised plant health. Zinc (Zn) foliar spray in nano form presents a potential solution to ameliorate water deficit stress. We attempt here a detailed dissection of electron transport in Photosystem II (PSII) through studies on chlorophyll a fast fluorescence kinetics and non-photochemical quenching (NPQ) and pigment dynamics in response to water stress. We also investigated the possible changes in these processes and the regulation of it by Zn Nano and Zn Ethylenediaminetetraacetic acid (EDTA) foliar sprays that may lead to amelioration of stress. Our results indicated that water stress created a "traffic jam" like situation in the electron transport system of Photosystem II, leading to decreased photosynthetic efficiency. Treatments with Water deficit stress + Zn Nano (particle size < 90 nm) spray with Zn concentration at 20 mg L−1 and Water deficit stress + Zn EDTA spray (solid material size ∼ 100 mm) with Zn concentration at 240 mg L−1 effectively ameliorated water deficit stress by its action on flux ratio parameters viz., quantum yield for electron transport (φE0), probability of electron transport beyond QA (ψ0) and quantum yield of electron transport from QA⁻ to PS1 end electron acceptors (ϕR0) and also the specific fluxes and phenomenological fluxes. These treatments positively influenced chlorophyll content, and xanthophyll components, including violaxanthin, antheraxanthin, and zeaxanthin, and reduced NPQ and the de expoxidation state. Higher concentrations of Zn Nano foliar spray (water stress + Zn Nano spray Zn @ 30 mg L⁻¹) did not ameliorate water deficit stress as effectively as the lower concentrations, although this higher concentration was not in any way toxic. This lack of stress amelioration at higher concentrations of Zn Nano spray may be due to physiological limitations of elemental zinc action within the plant. Our findings suggest that Zn foliar sprays in Nano and EDTA form at optimum concentrations can significantly improve plant resilience to water stress.

Exploring the dynamics of sports records evolution through the gembris prediction model and network relevance analysis

Background Sports records hold valuable insights into human physiological limits. However, presently, there is a lack of integration and evolutionary patterns in the recorded information across various sports. Methods We selected sports records from 1992 to 2018, covering 24 events in men’s track, field, and swimming. The Gembris prediction model calculated performance randomness, and Pearson correlation analysis assessed network relevance between projects. Quantitative study of model parameters revealed the impact of various world records’ change range, predicted value, and network correlation on evolutionary patterns. Results 1) The evolution range indicates that swimming events generally have a larger annual world record variation than track and field events; 2) Gembris’s predictions show that sprint, marathon, and swimming records outperform their predicted values annually; 3) Network relevance analysis reveals highly significant correlations between all swimming events and sprints, as well as significant correlations between marathon and all swimming events. Conclusion Sports record evolution is closely linked not only to specific sports technology but also to energy expenditure. Strengthening basic physical training is recommended to enhance sports performance.

Cold Pressor Test Induces Significant Changes in Internal Jugular Vein Flow Dynamics in Healthy Young Adults.

BACKGROUND The cold pressor test (CPT), which has long been used to test autonomic functions by causing sympathetic excitation, increases systolic and diastolic blood pressure and heart rate and causes coronary vasodilation within physiological limits in healthy individuals. This study aimed to evaluate internal jugular vein (IJV) flow parameters using the CPT with systolic and diastolic blood pressure and heart rate in 40 healthy volunteers aged 18-40 years. MATERIAL AND METHODS The volunteers' IJV diameter, blood flow peak velocity, and volumetric flow values were recorded. Then, their right hands were immersed in a bucket of cold water maintained at 1°C up to the wrist level. At the end of the first minute (CPT-1), systolic and diastolic blood pressure, heart rhythm, IJV diameter, peak velocity, and volumetric flow measurements were performed again. RESULTS Systolic and diastolic blood pressure values were significantly higher at CPT-1 compared to baseline values (P<0.001, P<0.001). Heart rate and peak velocity values also showed a significant increase at CPT-1 compared to baseline values (P<0.001, P=0.001). While diameter values showed a significant decrease compared to baseline, volumetric flow rate values showed a significant increase at CPT-1 (P=0.003, P<0.001). CONCLUSIONS Sympathetic nervous system activation triggered by CPT increases IJV volumetric flow and flow velocity in healthy young individuals, and sympathetic nervous system activation causes a venoconstrictive effect in the IJV.

Thermal and morphometric correlates of the extremely low rate of energy use in a wild frugivorous primate, the Mayotte lemur

Primates spend on average half as much energy as other placental mammals while expressing a wide range of lifestyles. However, little is known about how primates adapt their rate of energy use in the context of natural environmental variations. Using doubly labelled water, behavioral and accelerometric methods, we measured the total energy expenditure (TEE) and body composition of a population of Eulemur fulvus (N = 12) living in an agroforest in Mayotte. We show that the TEE of this medium-sized cathemeral primate is one of the lowest recorded to date in eutherians. Regression models show that individual variation in the rate of energy use is predicted by fat-free mass, body size, thigh thickness and maximum temperature. TEE is positively correlated with increasing temperature, suggesting that thermoregulation is an important component of the energy budget of this frugivorous species. Mass-specific TEE is only 10% lower than that of a closely related species previously studied in a gallery forest, consistent with the assertion that TEE varies within narrow physiological limits. As lemur communities include many species with unique thermoregulatory adaptations, circadian and/or seasonal temperature variations may have constituted a major selective pressure on the evolution of lemur metabolic strategies.

Temperature dependence of mosquitoes: Comparing mechanistic and machine learning approaches.

Mosquito vectors of pathogens (e.g., Aedes, Anopheles, and Culex spp. which transmit dengue, Zika, chikungunya, West Nile, malaria, and others) are of increasing concern for global public health. These vectors are geographically shifting under climate and other anthropogenic changes. As small-bodied ectotherms, mosquitoes are strongly affected by temperature, which causes unimodal responses in mosquito life history traits (e.g., biting rate, adult mortality rate, mosquito development rate, and probability of egg-to-adult survival) that exhibit upper and lower thermal limits and intermediate thermal optima in laboratory studies. However, it remains unknown how mosquito thermal responses measured in laboratory experiments relate to the realized thermal responses of mosquitoes in the field. To address this gap, we leverage thousands of global mosquito occurrences and geospatial satellite data at high spatial resolution to construct machine-learning based species distribution models, from which vector thermal responses are estimated. We apply methods to restrict models to the relevant mosquito activity season and to conduct ecologically plausible spatial background sampling centered around ecoregions for comparison to mosquito occurrence records. We found that thermal minima estimated from laboratory studies were highly correlated with those from the species distributions (r = 0.87). The thermal optima were less strongly correlated (r = 0.69). For most species, we did not detect thermal maxima from their observed distributions so were unable to compare to laboratory-based estimates. The results suggest that laboratory studies have the potential to be highly transportable to predicting lower thermal limits and thermal optima of mosquitoes in the field. At the same time, lab-based models likely capture physiological limits on mosquito persistence at high temperatures that are not apparent from field-based observational studies but may critically determine mosquito responses to climate warming. Our results indicate that lab-based and field-based studies are highly complementary; performing the analyses in concert can help to more comprehensively understand vector response to climate change.

143 Short- and long-term effects of heat stress in cow-calf pairs adapted to tropical and subtropical regions

Abstract Chronic exposure to high temperatures and humidity can limit beef cattle performance in tropical/subtropical environments, regardless of breed. Despite better heat adaptability compared with Bos taurus cattle, heat-stressed Bos indicus cattle also experience an increase in body temperature above the physiological limit. As body temperature increases, cascades of behavioral and physiological events are triggered to lessen heat load but often at the expense of productive outcomes. Contrary to other species and feedlot beef cattle, the effects of heat stress on physiology and performance of grazing cow-calf pairs have not been evaluated in detail, particularly for Bos indicus cattle. Preliminary data showed opposite outcomes to heat stress in Bos indicus vs. Bos taurus cattle, limiting the implications of the existing data generated from studies using beef and dairy Bos taurus cattle. This presentation will share some nutritional and management practices to mitigate heat stress in grazing beef cattle. Practices mentioned herein include altering the timing of body weight (BW) growth pattern (stair-step, SST) and immunomodulatory feed ingredient (IFI) supplementation for replacement beef heifers, and maternal access to shade to reduce heat load. For 100 d before the breeding season, Bos indicus-influenced beef heifers grazing warm-season grasses received a constant supplementation amount or SST strategy (50 d of low then 50 d of high supplementation), with or without IFI. Under severe heat stress conditions, IFI supplementation reduced heifer vaginal temperature but did not increase their growth and reproduction, whereas the SST strategy lowered internal body temperature, enhanced growth performance and pregnancy success compared with a conventional constant supplementation practice. Our group is also focused on the critical need to determine the specific effects of heat stress mitigation during pre- and postnatal phases on physiology and performance of Bos indicus-influenced cow-calf pairs. Study 1 evaluated the impacts of maternal access to artificial shade from 83 d prepartum until 50 d postpartum on body thermoregulation, performance, and physiology of beef heifers and their first offspring. Removing maternal access to shade led to greater maternal respiration rate, vaginal and body surface temperatures and reduced maternal body condition score and calf BW at birth. Nonetheless, offspring born from cows with no access to shade were remarkably heavier during a 60-d post-weaning period and had decreased plasma indicators of inflammation and positive effects to humoral immune response. Study 2 is a multi-year, USDA/NIFA-funded study designed to capitalize on the ability of cattle to reprogram physiological/immunological systems following exposure to stress during gestation. Study 2 combined gestational and postnatal heat abatement to enhance the overall growth/immune/reproductive performance of grazing Bos indicus-influenced cow-calf pairs. Partial data on long-term growth and reproductive performance, physiology, metabolome, and microbiome of both cows and their female offspring will be shared in this presentation.

Reproductive intentions of Russians in 2022—2023: Тhe role of subjective factors

This study examines how the reproductive intentions of Russians changed during the socio-economic shocks in 2022—2023 basing on the data from a representative survey of respondents of reproductive age conducted in May 2023. We used multiple-choice models to identify the factors that influenced changes in fertility decisions. Most individuals who had planned to have children before the crisis did not change their plans (60.2%), 9.5% of respondents decided not to have children, while, on the contrary, 9.2% decided to have children earlier. The rest of the respondents postponed having children. The econometric model included both objective and subjective characteristics of respondents. Objective factors included income, housing availability, health, family status, and the presence of children. Subjective factors comprised emotions such as anxiety, fear, appeasement, happiness, and attitude to the political course of the country. The study found that psychological factors played a more significant role in decision-making. Anxiety and fear as well as disagreement with the country’s political course led respondents to postpone having children for an indefinite period. Conversely, a positive emotional background and the presence of a partner encouraged respondents to have children earlier. The decision not to have children was mainly explained by physiological limitations and attitudes to political course, while the income and emotional indicators had a more minor but significant influence. The results of model estimates are consistent with the cluster analysis of answers to the openended question about changes in reproductive intentions. We also discovered significant differences in decision-making for respondents before and after the age of 30 as well as for those with and without children. A series of demographic and social policy recommendations are suggested.

Encapsulation of 4-oxo-N-(4-hydroxyphenyl) retinamide in human serum albumin nanoparticles promotes EZH2 degradation in preclinical neuroblastoma models.

Neuroblastoma is the most prevalent and aggressive solid tumor that develops extracranially in children between the ages of 0-14 years, which accounts for 8-10% of all childhood malignancies and ∼15% of pediatric cancer-related mortality. The polycomb repressive complex 2 (PRC2) protein, EZH2, is overexpressed in neuroblastoma and mediates histone H3 methylation at lysine 27 (K27) positions through its methyl transferase activity and is a potential epigenetic silencer of many tumor suppressor genes in cancer. Phosphorylation of EZH2 decreases its stability and leads to proteasomal degradation. The 4-oxo-N-(4-hydroxyphenyl) retinamide (4O4HPR) promotes EZH2 degradation via activation of PKC-δ, but its limited solubility and physiological instability limit its application. In the current study, the encapsulation of 4O4HPR in Human Serum Albumin Nanoparticles (HSANPs) enhanced the solubility and physiological stability of the nanoformulation, leading to improved therapeutic efficacy through G2-M cell cycle arrest, depolarization of mitochondrial membrane potential, generation of reactive oxygen species and caspase 3 mediated apoptosis activation. The molecular mechanistic approach of 4O4HPR loaded HSANPs has activated caspase 3, which further cleaves PKC-δ into two fragments wherein the cleaved fragment of PKC-δ possesses the kinase activity that phosphorylates EZH2 and decreases the protein stability leading to its further ubiquitination in SH-SY5Y cells. Co-immunoprecipitation experiments revealed the direct interaction between PKC-δ and EZH2 phosphorylation, followed by ubiquitination. Moreover, 4O4HPR loaded HSANPs demonstrated improved in vivo biodistribution, greater dispersibility, and biocompatibility and exhibited enhanced protein instability and degradation of EZH2 in the neuroblastoma xenograft mouse model.

Ecotones as Windows into Organismal-to-Biome Scale Responses across Neotropical Forests.

Tropical forests are incredibly diverse in structure and function. Despite, or perhaps because of, this diversity, tropical biologists often conduct research exclusively in one or perhaps a few forest types. Rarely do we study the ecotone-the interstitial region between forest types. Ecotones are hyper-diverse, dynamic systems that control the flow of energy and organisms between adjacent ecosystems, with their locations determined by species' physiological limits. In this review, we describe how studying ecotones can provide key indicators for monitoring the state of Neotropical forests from organisms to ecosystems. We first describe how ecotones have been studied in the past and summarize our current understanding of tropical ecotones. Next, we provide three example lines of research focusing on the ecological and evolutionary dynamics of the ecotone between tropical dry forests and desert; between tropical dry and rainforests; and between Cerrado and Atlantic rainforests, with the latter being a particularly well-studied ecotone. Lastly, we outline methods and tools for studying ecotones that combine remote sensing, new statistical techniques, and field-based forest dynamics plot data, among others, for understanding these important systems.

Beyond Nyquist: A Comparative Analysis of 3D Deep Learning Models Enhancing MRI Resolution.

High-spatial resolution MRI produces abundant structural information, enabling highly accurate clinical diagnosis and image-guided therapeutics. However, the acquisition of high-spatial resolution MRI data typically can come at the expense of less spatial coverage, lower signal-to-noise ratio (SNR), and longer scan time due to physical, physiological and hardware limitations. In order to overcome these limitations, super-resolution MRI deep-learning-based techniques can be utilised. In this work, different state-of-the-art 3D convolution neural network models for super resolution (RRDB, SPSR, UNet, UNet-MSS and ShuffleUNet) were compared for the super-resolution task with the goal of finding the best model in terms of performance and robustness. The public IXI dataset (only structural images) was used. Data were artificially downsampled to obtain lower-resolution spatial MRIs (downsampling factor varying from 8 to 64). When assessing performance using the SSIM metric in the test set, all models performed well. In particular, regardless of the downsampling factor, the UNet consistently obtained the top results. On the other hand, the SPSR model consistently performed worse. In conclusion, UNet and UNet-MSS achieved overall top performances while RRDB performed relatively poorly compared to the other models.

Interactive effects of water deficit and nitrogen deficiency on photosynthesis, its underlying component processes, and carbon loss processes in cotton

AbstractDrought stress and nitrogen (N) deficiency are important abiotic stresses that severely limit net photosynthetic rate (AN). A number of studies have investigated the underlying physiological limitations to AN in response to water deficit or N deficiency; however, the relative sensitivities of photosynthetic component processes and carbon loss processes to combined drought and N deficiency in field‐grown cotton (Gossypium hirsutum L.) have not been explored. Therefore, the objective of the present study was to determine the effects of combined water deficit and nitrogen deficiency on the underlying physiological processes driving AN in field‐grown cotton. Water‐deficit stress caused substantial reductions in AN, but reductions in AN were greater under optimum N conditions (74%) than under N deficiency (22%). Decreased CO2 diffusion, RuBP regeneration, and Rubisco carboxylation were major contributors to a decline in AN due to water‐deficit stress. Reductions in Rubisco carboxylation and RuBP regeneration were the greatest drivers of N deficiency‐induced decline in AN. Lower CO2 diffusion and Rubisco carboxylation were main constraints to AN due to combined water deficit and N deficiency. Regarding carbon loss processes, both dark respiration and photorespiration under water‐deficit stress or N deficiency, and only photorespiration under combined water deficit and N deficiency, contributed to declines in AN. Increased non‐photochemical quenching and/or photorespiration prevented photoinhibition of photosystem II under stress conditions. Overall, response of photosynthesis to water‐deficit stress was dependent on N availability, and rate‐limiting physiological processes contributing to declines in AN were dependent on the type of prevailing stress.

Zinc-doped phosphate coatings for enhanced corrosion resistance, antibacterial properties, and biocompatibility of AZ91D Mg alloy

Magnesium and its alloys have been foreseen as promising bone-implant owing to good biocompatibility, high strength, mechanical properties, and biodegradability to replace the conventional bio-metals (Titanium, stainless-steel, Co-Cr alloys) in orthopedic applications. However, high corrosion rate and high degradation rates adversely effects like abrupt evolution of H2 gas and localized alkalization in a physiological environment limit its medical applications. To overcome these issues, phosphate-based surface coating is developed on Mg-alloy to resist the high biodegradation and corrosion rate utilizing magnesium substrate as source of magnesium ion through a single-step hydrothermal process. Controlling the fast corrosion rate and localized alkalization would reduce the antibacterial character of magnesium-based implants therefore, the simple phosphate-based coatings has been induced by doping it with zinc ions due to its physiological tolerance and excellent antibacterial efficacy. The doping of zinc ions may provide a sustained drug-free antibacterial characteristic for potential application in orthopedics. The synthesized phosphate-based coating was characterized using advanced techniques like Scanning Electron Microscopy, X-ray Diffraction, and wettability test, followed by comprehensive electrochemical testing to assess its corrosion behavior. The in vitro immersion test in simulated body fluid (SBF) indicates that deposition of phosphate and zinc doped phosphate coatings reduces the degradation rate consequently minimized the fast dissolution of Mg2+ ions and OH- in physiological environment. Additionally, cytotoxicity and biocompatibility were evaluated using Alamar Blue and live/dead assays on the MC3T3-E1 mouse osteoblast cell line. These assays demonstrated good cell viability, indicating the coatings possess favorable cytocompatibility and support cellular metabolic activity.

Effect of heat exposure on histology, transcriptomics and co-expression network: A synthetic study in Japanese flounder (Paralichthys olivaceus)

Water temperature has continued to increase as part of global warming. The heart of fish is the center that participates in the physiological limitations of thermal performance. However, only a few studies have focused on the response mechanisms of fish hearts to heat stress. Therefore, the economically important cold-water aquaculture fish, Japanese flounder (Paralichthys olivaceus) was chosen to explore the mechanisms of the heart in response to heat stress. Histological observations indicated that heat stress could widen the sarcoplasmic distance and deepen chromatin staining. Further transcriptome analysis identified 958 differentially expressed genes (DEGs), and significantly enriched “Protein processing in endoplasmic reticulum” pathway and related terms in functional enrichment analysis. Weighted gene co-expression network analysis (WGCNA) showed that different tissues had different response modules and hub genes, and calcium ions (Ca2+) related genes and pathways were noteworthy in the heart specific module. Functional identification of key Ca2+ regulatory hub genes illuminated that caveolin-3 (cav3) was an important gene that participates in controlling the Ca2+ into and out of cells. Meanwhile, overexpression of cav3 could reduce heat stress induced apoptosis. This study could not only be a crucial resource for the response mechanisms underlying heat stress in Japanese flounder, but also provide valuable insights into genetic improvement for heat-resistance.