Search

Background: Ammonia-oxidizing archaea (AOA) of the phylum Thaumarchaeota mediate the rate-limiting step of nitrification and remove the ammonia that inhibits the aerobic metabolism of methanotrophs. However, the AOA that inhabit deep-sea methane-seep surface sediments (DMS) are rarely studied. Here, we used global DMS metagenomics and metagenome-assembled genomes (MAGs) to investigate the metabolic activity, evolutionary history, and ecological contributions of AOA. Expression of AOA-specific ammonia-oxidizing gene (amoA) was examined in the sediments collected from the South China Sea (SCS) to identify their active ammonia metabolism in the DMS. Results: Our analysis indicated that AOA contribute > 75% to the composition of ammonia-utilization genes within the surface layers (above 30 cm) of global DMS. The AOA-specific ammonia-oxidizing gene was actively expressed in the DMS collected from the SCS. Phylogenomic analysis of medium-/high-quality MAGs from 18 DMS-AOA indicated that they evolved from ancestors in the barren deep-sea sediment and then expanded from the DMS to shallow water forming an amoA-NP-gamma clade-affiliated lineage. Molecular dating suggests that the DMS-AOA origination coincided with the Neoproterozoic oxidation event (NOE), which occurred ~ 800 million years ago (mya), and their expansion to shallow water coincided with the Sturtian glaciation (~ 713 mya). Comparative genomic analysis suggests that DMS-AOA exhibit higher requirement of carbon source for protein synthesis with enhanced genomic capability for osmotic regulation, motility, chemotaxis, and utilization of exogenous organic compounds, suggesting it could be more heterotrophic compared with other lineages. Conclusion: Our findings provide new insights into the evolutionary history of AOA within the Thaumarchaeota, highlighting their critical roles in nitrogen cycling in the global DMS ecosystems. EWMb7UH3jhRcWd8tHNUGyq Video Abstract [ABSTRACT FROM AUTHOR]

The fish gill serves many physiological functions, among which is the excretion of ammonia, the primary nitrogenous waste in most fishes. Although it is the end-product of nitrogen metabolism, ammonia serves many physiological functions including acting as an acid equivalent and as a counter-ion in mechanisms of ion regulation. Our current understanding of the mechanisms of ammonia excretion have been influenced by classic experimental work, clever mechanistic approaches, and modern molecular and genetic techniques. In this review, I will overview the history of the study of ammonia excretion by the gills of fishes, highlighting the important advancements that have shaped this field with a nearly 100-year history. The developmental and evolutionary implications of an ammonia and gill-dominated nitrogen regulation strategy in most fishes will also be discussed. Throughout the review, I point to areas in which more work is needed to push forward this field of research that continues to produce novel insights and discoveries that will undoubtedly shape our overall understanding of fish physiology. [ABSTRACT FROM AUTHOR]

Since 2000, a well‐established population of the invasive oriental shrimp Palaemon macrodactylus has been present in fully marine conditions in the southwestern Atlantic Ocean (~38° S). To assess the physiological performance of this atypical population restricted to fully marine conditions, we conducted a laboratory experiment in which individuals were transferred from 35 ‰S (local seawater) to 2 ‰S; 5 ‰S; 10 ‰S; 20 ‰S; 50 ‰S and 60‰ for short (6 h), medium (48 h), and long (>504 h) acclimation periods. We measured the time course response of relevant parameters in the shrimp's hemolymph; activity of Na+, K+‐ATPase (NKA), and V‐H+‐ATPase (VHA); and muscle water content. Shrimp showed great osmoregulatory plasticity, being able to survive for long periods between 5 ‰S and 50 ‰S, whereas no individual survived after transfer to either 2 ‰S or 60 ‰S. Shrimp hyper‐regulated hemolymph osmolality at 5 ‰S and 10 ‰S, hypo‐regulated at 35 ‰S and 50 ‰S, and isosmoticity was close to 20 ‰S. Compared to 35 ‰S, prolonged acclimation to 5 ‰S caused a decrease in hemolymph osmolality (~34%) along with sodium and chloride concentrations (~24%); the NKA and VHA activities decreased by ~52% and ~88%, respectively, while muscle water content was tightly regulated. Our results showed that the atypical population of P. macrodactylus studied here lives in a chronic hypo‐osmo‐ion regulatory state and suggest that fully marine conditions contribute to its poor performance at the lower limit of salinity tolerance (<5 ‰S). Research Highlights: Shrimp lives in a chronic hypo‐osmo‐ionic regulatory state.Shrimp can tolerate brackish water but not freshwater.An incipient local physiological adaptation to full‐strength seawater is suggested. [ABSTRACT FROM AUTHOR]

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

Essential mineral elements such as zinc and iron play a crucial role in maintaining crop growth and development, as well as ensuring human health. Foxtail millet is an ancient food crop rich in mineral elements and constitutes an important dietary supplement for nutrient-deficient populations. The ZIP (ZRT, IRT-like protein) transporters are primarily responsible for the absorption, transportation and accumulation of Zn, Fe and other metal ions in plants. Here, we identified 14 ZIP transporters in foxtail millet (SiZIP) and systematically characterized their phylogenetic relationships, expression characteristics, sequence variations, and responses to various abiotic stresses. As a result, SiZIPs display rich spatiotemporal expression characteristics in foxtail millet. Multiple SiZIPs demonstrated significant responses to Fe, Cd, Na, and K metal ions, as well as drought and cold stresses. Based on homologous comparisons, expression characteristics and previous studies, the functions of SiZIPs were predicted as being classified into several categories: absorption/efflux, transport/distribution and accumulation of metal ions. Simultaneously, a schematic diagram of SiZIP was drawn. In general, SiZIPs have diverse functions and extensively involve in the transport of metal ions and osmotic regulation under abiotic stresses. This work provides a fundamental framework for the transport and accumulation of mineral elements and will facilitate the quality improvement of foxtail millet. [ABSTRACT FROM AUTHOR]

Freshwater scarcity demands exploration of alternative resources like saline water and soils. Understanding the molecular mechanisms behind NaCl regulation in potential crop plants becomes increasingly important for promoting saline agriculture. This study investigated the euhalophyte Salicornia europaea, analyzing its gene expression, yield, and total phenolic compounds under hydroponic cultivation. We employed five salinity levels (0, 7.5, 15, 22.5, and 30 g/L NaCl) across five harvests at 15-day intervals, capturing plant development. Notably, this design deviated from conventional gene expression studies by recording organ-specific responses (shoots and roots) in plants adapted to long-term salinity treatments at various developmental stages. The highest freshmass of S. europaea was observed fourmonths after germination in 15 g/L NaCl. Identifying a reliable set of reference genes for normalizing gene expression data was crucial due to comparisons across shoots, roots, developmental stages, and salinity levels. A set of housekeeping genes -ubiquitin c (SeUBC), actin (SeActin) anddnaJ-like protein (SeDNAJ) - was identified for this purpose. Interestingly, plants grown without NaCl (0 g/L) displayed upregulation of certain genes associated with a NaCl deficiency related nutritional deprivation. These genes encode a tonoplast Na+/H+-antiporter (SeNHX1), a vacuolar H+-ATPase (SeVHA-A), two H+-PPases (SeVP1, SeVP2), a hkt1-like transporter (SeHKT), a vinorine synthase (SeVinS), a peroxidase (SePerox), and a plasma membrane Na+/H+-antiporter (SeSOS1). Other genes encoding an amino acid permease (SeAAP) and a proline transporter (SeProT) demonstrated marginal or dispersing salinity influence, suggesting their nuanced regulation during plants development. Notably, osmoregulatory genes (SeOsmP, SeProT) were upregulated in mature plants, highlighting their role in salinity adaptation. This study reveals distinct regulatory mechanisms in S. europaea for copingwith varying salinity levels. Identifying and understanding physiological reactions and sodium responsive key genes further elucidate the relationship between sodium tolerance and the obligate sodium requirement as a nutrient in euhalophytes. [ABSTRACT FROM AUTHOR]

This study investigated the effects of exogenous nitric oxide (NO) on growth, antioxidant enzymes, and key nitrogen metabolism enzymes in pepper seedlings under high-temperature stress. In addition, targeted metabolomics was used to study the differential accumulation of amino acid metabolites, thereby providing theoretical support for the use of exogenous substances to mitigate high-temperature stress damage in plants. The results showed that high-temperature stress increased soluble sugar, soluble protein, amino acids, proline, malondialdehyde (MDA), and hydrogen peroxide (H2O2) content, electrolyte leakage, and superoxide anion (O2·-) production rate while altering the activities of antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX)] and key nitrogen metabolism enzymes [nitrate reductase (NR), glutamine synthetase (GS), glutamate dehydrogenase (GDH), and nitric oxide synthase (NOS)]. c-PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide, an NO scavenger) exacerbates oxidative stress and further reduces NO content and enzyme activities. However, exogenous SNP (sodium nitroprusside, an NO donor) effectively alleviated these adverse effects by enhancing antioxidant defense mechanisms, increasing NO content, and normalizing amino acid metabolite levels (kynurenine, N-acetyl-L-tyrosine, L-methionine, urea, and creatine), thereby maintaining normal plant growth. These findings suggest that SNP can enhance stress tolerance in pepper seedlings by improving osmotic regulation, antioxidant capacity, and nitrogen metabolism, effectively mitigating the damage caused by high-temperature stress. [ABSTRACT FROM AUTHOR]

Perlecan is a widely distributed, modular, and multifunctional heparan sulfate proteoglycan, which facilitates cellular communication with the extracellular environment to promote tissue development, tissue homeostasis, and optimization of biomechanical tissue functions. Perlecan‐mediated osmotic mechanotransduction serves to regulate the metabolic activity of cells in tissues subjected to tension, compression, or shear. Perlecan interacts with a vast array of extracellular matrix (ECM) proteins through which it stabilizes tissues and regulates the proliferation or differentiation of resident cell populations. Here we examine the roles of the HS‐proteoglycan perlecan in the normal and destabilized intervertebral disc. The intervertebral disc cell has evolved to survive in a hostile weight bearing, acidic, low oxygen tension, and low nutrition environment, and perlecan provides cytoprotection, shields disc cells from excessive compressive forces, and sequesters a range of growth factors in the disc cell environment where they aid in cellular survival, proliferation, and differentiation. The cells in mechanically destabilized connective tissues attempt to re‐establish optimal tissue composition and tissue functional properties by changing the properties of their ECM, in the process of chondroid metaplasia. We explore the possibility that perlecan assists in these cell‐mediated tissue remodeling responses by regulating disc cell anabolism. Perlecan's mechano‐osmotic transductive property may be of potential therapeutic application. [ABSTRACT FROM AUTHOR]

Soil salinization significantly impacts the ecological environment and agricultural production, posing a threat to plant growth. Currently, there are over 400 varieties of Bougainvillea with horticultural value internationally. However, research on the differences in salt tolerance among Bougainvillea varieties is still insufficient. Therefore, this study aims to investigate the physiological responses and tolerance differences of various Bougainvillea varieties under different concentrations of salt stress, reveal the effects of salt stress on their growth and physiology, and study the adaptation mechanisms of these varieties related to salt stress. The experimental materials consisted of five varieties of Bougainvillea. Based on the actual salinity concentrations in natural saline-alkali soils, we used a pot-controlled salt method for the experiment, with four treatment concentrations set: 0.0% (w/v) (CK), 0.2% (w/v), 0.4% (w/v), and 0.6% (w/v). After the Bougainvillea plants grew stably, salt stress was applied and the growth, physiology, and salt tolerance of the one-year-old plants were systematically measured and assessed. The key findings were as follows: Salt stress inhibited the growth and biomass of the five varieties of Bougainvillea; the 'Dayezi' variety showed severe salt damage, while the 'Shuihong' variety exhibited minimal response. As the salt concentration and duration of salt stress increase, the trends of the changes in antioxidant enzyme activity and osmotic regulation systems in the leaves of the five Bougainvillea species differ. Membrane permeability and the production of membrane oxidative products showed an upward trend with stress severity. The salt tolerance of the five varieties of Bougainvillea was comprehensively evaluated through principal component analysis. It was found that the 'Shuihong' variety exhibited the highest salt tolerance, followed by the 'Lvyehuanghua', 'Xiaoyezi', 'Tazi', and 'Dayezi' varieties. Therefore, Bougainvillea 'Shuihong', 'Lvyehuanghua', and 'Xiaoyezi' are recommended for extensive cultivation in saline-alkali areas. The investigation focuses primarily on how Bougainvillea varieties respond to salt stress from the perspectives of growth and physiological levels. Future research could explore the molecular mechanisms behind the responses to and tolerance of different Bougainvillea varieties as to salt stress, providing a more comprehensive understanding and basis for practical applications. [ABSTRACT FROM AUTHOR]

With global warming, drought stress is becoming increasingly severe, causing serious impacts on crop yield and quality. In order to survive under adverse conditions such as drought stress, plants have evolved a certain mechanism to cope. The tolerance to drought stress is mainly improved through the synergistic effect of regulatory pathways, such as transcription factors, phytohormone, stomatal movement, osmotic substances, sRNA, and antioxidant systems. This study summarizes the research progress on plant drought resistance, in order to provide a reference for improving plant drought resistance and cultivating drought-resistant varieties through genetic engineering technology. [ABSTRACT FROM AUTHOR]

The original UT-1 transporter gene was initially identified in the spiny dogfish (Squalus acanthias), but localization of the UT-1 protein was not determined. Subsequent UT-1 expression was shown to localize to the collecting tubule (CT) of the shark nephron in other shark species, with expression in a closely related chimaera species also located additionally at a lower level in the intermediate-I segment (IS-I) of the nephron. In spiny dogfish, two UT-1 splice variants are known (UT-1 long and short), and there was also a second UT-1 gene described (here termed Brain UT). In this study, a second splice variant of the second Brain UT gene was discovered. Expression profiles (mRNA) of UT-1 long and short and Brain UT were determined in a number of spiny dogfish tissues. Quantitative PCR in kidney samples showed that the level of the short variant of UT-1 was around 100 times higher than the long variant, which was itself expressed around 10 times higher than Brain UT cDNA/mRNA (in kidney). For the long variant, there was a significantly higher level of mRNA abundance in fish acclimatized to 75% seawater. Ultimately, three UT-1 antibodies were made that could bind to both the UT-1 short and long variant proteins. The first two of these showed bands of appropriate sizes on Western blots of around 52.5 and 46 kDa. The second antibody had some additional lower molecular weight bands. The third antibody was mainly bound to the 46 kDa band with faint 52.5 kDa staining. Both the 52.5 and 46 kDa bands were absent when the antibodies were pre-blocked with the peptide antigens used to make them. Across the three antibodies, there were many similarities in localization but differences in subcellular localization. Predominantly, antibody staining was greatest in the intermediate segment 1 (IS-I) and proximal (PIb) segments of the first sinus zone loop of the nephron, with reasonably strong expression also found at the start and middle of the late distal tubule (LDT; second sinus zone loop). While some expression in the collecting tubule (CT) could not be ruled out, the level of staining seemed to be low or non-existent in convoluted bundle zone nephron segments such as the CT. Hence, this suggests that spiny dogfish have a fundamentally different mode of urea absorption in comparison to that found in other shark species, potentially focused more on the nephron sinus zone loops than the CT. [ABSTRACT FROM AUTHOR]

Salinity significantly affects shellfish metabolism and growth. In this study, we evaluated the characterization of metabolomic differences in the juvenile black-shelled pearl oyster, Pinctada fucata martensii, under 15‰ (LSG), 25‰ (CG), and 35‰ (HSG) salinity conditions. Non-targeted metabolomics analyses revealed that salinity stress altered the metabolism of pearl oyster. A total of 229 significant differential metabolites (SDMs) were identified between LSG and CG via an in-house MS2 database, 241 SDMs were identified between LSG and HSG, and 50 SDMs were identified between CG and HSG. The pathway analysis showed that 21 metabolic pathways were found between LSG and CG, such as arginine and proline metabolism, glycerophospholipid metabolism, and pentose and glucuronide interconversion. A total of 23 metabolic pathways were obtained between LSG and HSG, such as aspartate, alanine, and glutamate metabolism. Only aminoacyl-tRNA biosynthesis, cysteine and methionine metabolism, and biotin metabolism were enriched between CG and HSG. A further integrated analysis suggested that amino acid metabolism might participate in osmoregulation and energy metabolism to respond to salinity stress in P. f. martensii, and the metabolic pathways differed under varying salinity stress conditions. In addition, low salinity stress might promote apoptosis in pearl oysters. Altogether, these results clarify the salinity tolerance mechanism of pearl oysters. [ABSTRACT FROM AUTHOR]

Euryhaline fishes acclimate to various osmotic environments by changing the direction of water and ion transport between body fluids and environmental waters. Ionocytes in the gills are one of the most important cells for the active ion transport. This study aimed to identify the molecules responsible for apical Cl− transport in rainbow trout ionocytes. Tissue distribution and time-course changes after seawater transfer were analyzed for mRNA expression of slc26a6, cftr1, and cftr2. slc26a6 was specifically expressed in the freshwater gills and decreased after seawater transfer. Both cftr genes were expressed in the gills and higher in seawater; however, the magnitude of expression increase after seawater transfer was greater in cftr1 than in cftr2. These results suggest that Cftr1 is mainly functioned in hypo-osmoregulation and that Cftr2 may also be involved in ion transport under freshwater conditions, such as acid–base regulation. Slc26a6 was localized at the apical membrane of Nkcc1-negative ionocytes only in freshwater-acclimated trout. Apical Cftr1 localization was also identified in most of ionocytes in seawater-acclimated fish. These results indicate that Slc26a6 in freshwater and Cftr1 in seawater contribute to osmoregulatory Cl− transport across the apical membrane of ionocytes in rainbow trout. [ABSTRACT FROM AUTHOR]

Many flatfish species are partially euryhaline, such as the Pacific sanddab which spawn and feed in highly dynamic estuaries ranging from seawater to near freshwater. With the rapid increase in saltwater invasion of freshwater habitats, it is very likely that in these estuaries, flatfish will be exposed to increasing levels of dissolved organic carbon (DOC) of freshwater origin at a range of salinities. As salinity fluctuations often coincide with changes in DOC concentration, two natural freshwater DOCs [Luther Marsh (LM, allochthonous) and Lake Ontario (LO, autochthonous) were investigated at salinities of 30 and 7.5 ppt. Optical characterization of the two natural DOC sources indicate salinity-dependent differences in their physicochemistry. LO and LM DOCs, as well as three model compounds [tannic acid (TA), sodium dodecyl sulfate (SDS) and bovine serum albumin (BSA)] representing key chemical moieties of DOC, were used to evaluate physiological effects on sanddabs. In the absence of added DOC, an acute decrease in salinity resulted in an increase in diffusive water flux (a proxy for transcellular water permeability), ammonia excretion and a change in TEP from positive (inside) to negative (inside). The effects of DOC (10 mg C L-1) were salinity and source-dependent, with generally more pronounced effects at 30 than 7.5 ppt, and greater potency of LM relative to LO. Both LM DOC and SDS increased diffusive water flux at 30 ppt but only SDS had an effect at 7.5 ppt. TA decreased ammonia excretion at 7.5 ppt. LO DOC decreased urea-N excretion at both salinities whereas the stimulatory effect of BSA occurred only at 30 ppt. Likewise, the effects of LM DOC and BSA to reduce TEP were present at 30 ppt but not 7.5 ppt. None of the treatments affected oxygen consumption rates. Our results demonstrate that DOCs and salinity interact to alter key physiological processes in marine flatfish, reflecting changes in both gill function and the physicochemistry of DOCs between 30 and 7.5 ppt. [ABSTRACT FROM AUTHOR]

Stachydrine, also known as proline betaine, is a prominent constituent of traditional Chinese herb Leonurus japonicus, renowned for its significant pharmacological effects. Widely distributed in plants like Leonurus and Citrus aurantium, as well as various bacteria, stachydrine serves pivotal physiological functions across animal, plant, and bacterial kingdoms. This review aims to summarizes diverse roles and mechanisms of stachydrine in addressing cardiovascular and cerebrovascular diseases, neuroprotection, anticancer activity, uterine regulation, anti-inflammatory response, obesity management, and respiratory ailments. Notably, stachydrine exhibits cardioprotective effects via multiple pathways encompassing anti-inflammatory, antioxidant, antiapoptotic, and modulation of calcium handling functions. Furthermore, its anti-cancer properties inhibit proliferation and migration of numerous cancer cell types. With a bi-directional regulatory effect on uterine function, stachydrine holds promise for obstetrics and gynecology-related disorders. In plants, stachydrine serves as a secondary metabolite, contributing to osmotic pressure regulation, nitrogen fixation, pest resistance, and stress response. Similarly, in bacteria, it plays a crucial osmoprotective role, facilitating adaptation to high osmotic pressure environments. This review also addresses ongoing research on the anabolic metabolism of stachydrine. While the biosynthetic pathway remains incompletely understood, the metabolic pathway is well-established. A deeper understanding of stachydrine biosynthesis holds significance for elucidating its mechanism of action, advancing the study of plant secondary metabolism, enhancing drug quality control, and fostering new drug development endeavors. [ABSTRACT FROM AUTHOR]

Copyright of Feed Research is the property of Editorial Board of Feed Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cronobacter condimenti are environmental commensals that have not been associated with any clinical infections. To date, they are the least understood and described Cronobacter species within the genus. The objective of this study was to use a draft genome sequence (DGS) of the Cronobacter condimenti strain s37 to screen for genes encoding for antibiotic resistance, virulence, response to environmental stress, and biofilm formation. The strain was isolated in Poland from commercial small radish sprouts. This is the second genome of this species available in the GenBank database. The comparative genome analysis (cgMLST) of C. condimenti s37 with other Cronobacter spp. including the pathogenic species C. sakazakii and the plant-associated closely related genera Franconibacter and Siccibacter was also performed. The assembled and annotated genome of the C. condimenti s37 genome was 4,590,991 bp in length, with a total gene number of 4384, and a GC content of 55.7%. The s 37 genome encoded for genes associated with resistance to stressful environmental conditions (metal resistance genes: zinc, copper, osmotic regulation, and desiccation stress), 17 antimicrobial resistance genes encoding resistance to various classes of antibiotics and 50 genes encoding for the virulence factors. The latter were mainly genes associated with adhesion, chemotaxis, hemolysis, and biofilm formation. Cg-MLST analysis (3991 genes) revealed a greater similarity of C. condimenti s37 to S. turicensis, F. pulveris, and C. dublinensis than to other species of the genus Cronobacter. Studies on the diversity, pathogenicity, and virulence of Cronobacter species isolated from different sources are still insufficient and should certainly be continued. Especially the analysis of rare strains such as s37 is very important because it provides new information on the evolution of these bacteria. Comparative cgMLST analysis of s37 with other Cronobacter species, as well as closely related genera Franconibacter and Siccibacter, complements the knowledge on their adaptability to specific environments such as desiccation. [ABSTRACT FROM AUTHOR]

To elucidate the function of the cold-resistance regulatory gene FmNAC1 from Fraxinus mandshurica Rupr., this study identified the role that overexpression of the FmNAC1 gene plays in tobacco growth and cold-stress regulation. The cloned FmNAC1 gene from F. mandshurica is 891 bp in length and encodes 296 amino acids. Our subcellular localization analysis confirmed that FmNAC1 is primarily located in the nucleus and functions as a transcription factor. FmNAC1 is responsive to cold and NaCl stress, as well as to the induction of IAA, GA, and ABA hormone signals. To further elucidate its function in cold resistance, four transgenic tobacco lines expressing FmNAC1 (FmNAC1-OE) were generated through tissue culture after the Agrobacterium-mediated transformation of wild-type (WT) Nicotiana tabacum L. These FmNAC1-OE plants exhibited accelerated growth after transplantation. When exposed to low-temperature conditions at −5 °C for 24 h, the rates of wilting and yellowing of the FmNAC1-OE plants were significantly lower than those of the WT tobacco plants. Additionally, the membrane integrity, osmotic regulation, and reactive oxygen species (ROS)-scavenging abilities of the FmNAC1-OE tobacco lines were better than those of the WT plants, indicating the potential of the FmNAC1 gene to improve plant cold resistance. The gene expression results further revealed that the FmNAC1 transcription factor exhibits regulatory interactions with growth-related genes such as IAA and AUX1; cold-resistance-related genes such as ICE, DREB, and CBF1; and genes involved in the clearance of reactive oxygen species (ROS), such as CAT and SOD. All of this evidence shows that the FmNAC1 transcription factor from F. mandshurica plays a key role in contributing to the enhancement of growth, cold resistance, and ROS clearance in transgenic tobacco plants. [ABSTRACT FROM AUTHOR]

A factorial design consisting of four N treatments (no N fertilization, 0.70, 0.14, and 0.28 mol N·plant−1) combined with two water conditions, drought (D = 25 ± 5% soil moisture content) and well-watered (W = 65 ± 5% soil moisture content), was used. Overall, the gas exchange parameters, chlorophyll, and growth of T. sinensis seedlings were significantly inhibited under drought conditions, while all of them showed improvement with N fertilizer, particularly at 0.14~0.28 mol N·plant−1. Under drought conditions, the root length and root surface area of T. sinensis increased; N application positively influenced the above root morphological changes. The activities of antioxidant enzymes such as superoxide dismutase (SOD; EC1.15.1.1) and peroxidase (POD; EC1.11.1.7) and the contents of osmotic adjustment substances such as soluble sugar and proline increased upon drought stress, but decreased under N application conditions. Overall, T. sinensis responds to drought stress through the synergistic action of drought resistance and drought tolerance mechanisms. N application enhances photosynthesis and improves root morphology, compensating for the need for osmotic regulation and reactive oxygen species scavenging. [ABSTRACT FROM AUTHOR]

Aqueous humor drainage from the anterior eye determines intraocular pressure (IOP) under homeostatic and pathological conditions. Swelling of the trabecular meshwork (TM) alters its flow resistance but the mechanisms that sense and transduce osmotic gradients remain poorly understood. We investigated TM osmotransduction and its role in calcium and chloride homeostasis using molecular analyses, optical imaging, and electrophysiology. Anisosmotic conditions elicited proportional changes in TM cell volume, with swelling, but not shrinking, evoking elevations in intracellular calcium concentration [Ca2+]TM. Hypotonicity-evoked calcium signals were sensitive to HC067047, a selective blocker of TRPV4 channels, whereas the agonist GSK1016790A promoted swelling under isotonic conditions. TRPV4 inhibition partially suppressed hypotonicity-induced volume increases and reduced the magnitude of the swelling-induced membrane current, with a substantial fraction of the swelling-evoked current abrogated by Cl− channel antagonists 4,4′-diisothiocyanato-2,2′-stilbenedisulfonic acid (DIDS) and niflumic acid. The transcriptome of volume-sensing chloride channel candidates in primary human was dominated by ANO6 transcripts, with moderate expression of ANO3, ANO7, and ANO10 transcripts and low expression of LTTRC genes that encode constituents of the volume-activated anion channel. Imposition of 190 mosM but not 285 mosM hypotonic gradients increased conventional outflow in mouse eyes. TRPV4-mediated cation influx thus works with Cl− efflux to sense and respond to osmotic stress, potentially contributing to pathological swelling, calcium overload, and intracellular signaling that could exacerbate functional disturbances in inflammatory disease and glaucoma. NEW & NOTEWORTHY: Intraocular pressure is dynamically regulated by the flow of aqueous humor through paracellular passages within the trabecular meshwork (TM). This study shows hypotonic gradients that expand the TM cell volume and reduce the outflow facility in mouse eyes. The swelling-induced current consists of TRPV4 and chloride components, with TRPV4 as a driver of swelling-induced calcium signaling. TRPV4 inhibition reduced swelling, suggesting a novel treatment for trabeculitis and glaucoma. [ABSTRACT FROM AUTHOR]

Aims: There are few studies on the interaction between selenium (Se) and various plant hormones in mitigating the harmful effects of cold stress on plants. Here, the effects of Se and various plant hormones on Solanum lycopersicum L. (tomato) under cold stress have been investigated to identify a combination of Se and plant hormones that enhances cold resistance. Methods: The tomato plants were treated with Se and various plant hormones including salicylic acid (SA), melatonin (MT), and abscisic acid (ABA) respectively. The chlorophyll fluorescence was measured by a Chlorophyll fluorescence IMAGING system. The photosynthetic pigments, malondialdehyde, and sugar contents were measured by an ultraviolet spectrophotometer. Results: Among several plant hormones, the co-application of Se and SA was the most effective in mitigating the cold stress of plants. The treatment of Se/SA preserved the plasma membrane integrity and regulated the osmotic substances under cold stress. The interaction between Se and SA modulated some cold-induced genes thereby conferring cold resistance of tomato plants. However, the pretreatment with AIP (SA biosynthesis inhibitor) eliminated the favorable influence of Se on the cold resistance of tomatoes, indicating that regulating the synthesis of SA was one of the mechanisms by which Se enhanced the resistance of tomato plants to cold stress. Conclusions: Our results clarified the roles of Se and its regulation mechanisms in plant cold stress tolerance, as well as the critical involvement of SA in this process, which might provide a theoretical foundation for using Se fertilizer to increase crop production under adversity conditions. Highlights: The combined treatment of Se with SA, MT, and ABA had better effects on enhancing the cold stress resistance of tomato plants than the treatment of Se or hormone alone. Among them, the combined application of Se and SA had the best effect on alleviating the cold stress of tomato plants compared with the ComCat® (a commercial compound plant growth regulator). The co-application of Se and SA also prevented the oxidative damage caused by cold stress on tomato plant chloroplasts and preserved the plasma membrane integrity, as shown by an obvious decrease in MDA, H2O2, and O2−. levels during cold stress. The Se/SA treatment could also reduce the content of reducing sugar, sucrose, total soluble sugar, and starch accumulation caused by cold stress through the regulation of osmotic substances, so as to improve the cold resistance of plants. The interaction between Se and SA modulated the expression of several cold-responsive genes, including PR1, ICE1, CYSb, LEA1, Osmotin, and CBF1, thereby conferring cold tolerance of tomato plants. The pretreatment with a SA inhibitor (AIP) eliminated the favorable influence of Se on the cold resistance of tomato plants indicating that enhancing the cold resistance of plants by regulating the synthesis pathway of SA might be one of the mechanisms by which Se enhanced tomato resistance to cold stress. [ABSTRACT FROM AUTHOR]

Excess fine sediment (particles <2 mm) delivery and deposition in freshwater systems is a significant factor in structuring aquatic communities and populations.Invertebrate gill surfaces can become covered with fine sediment, potentially compromising osmoregulatory function.Ionocytes are specialised structures for osmoregulation found on the tracheal gills of mayflies. The number of cells has been shown to change in order to maintain osmoregulatory demands under environmentally variable conditions.To investigate whether ionocytes vary in response to fine sediment pressure, individuals of Baetis rhodani were collected from two high and low fine sediment cover sites, respectively, in the UK. Tracheal gills were subsequently examined for the number of ionocytes present on the upper and lower gill surfaces, standardised by gill size.Results indicated that the number of ionocytes was significantly higher for mayflies collected from areas with high fine sediment cover. High fine sediment sites were also characterised by lower altitude and dissolved oxygen concentrations. Mayfly gills collected from high sediment cover sites were also significantly larger than those collected from low sediment sites.The results illustrate the potential for mayfly larvae to demonstrate phenotypic plasticity to the pressures associated with fine sediment but that these responses are likely dependent on the composition of fine sediment deposits (organic or mineral) and associated oxygen concentrations. [ABSTRACT FROM AUTHOR]

Hagfishes are characterized by omo- and iono-conforming nature similar to marine invertebrates. Conventionally, hagfishes had been recognized as the most primitive living vertebrate that retains plesiomorphic features. However, some of the "ancestral" features of hagfishes, such as rudimentary eyes and the lack of vertebrae, have been proven to be deceptive. Similarly, by the principle of maximum parsimony, the unique body fluid regulatory strategy of hagfishes seems to be apomorphic, since the lamprey, another cyclostome, adopts osmo- and iono-regulatory mechanisms as in jawed vertebrates. Although hagfishes are unequivocally important in discussing the origin and evolution of the vertebrate osmoregulatory system, the molecular basis for the body fluid homeostasis in hagfishes has been poorly understood. In the present study, we explored this matter in the inshore hagfish, Eptatretus burgeri, by analyzing the transcriptomes obtained from the gill, kidney, and muscle of the animals acclimated to distinct environmental salinities. Together with the measurement of parameters in the muscular fluid compartment, our data indicate that the hagfish possesses an ability to conduct free amino acid (FAA)-based osmoregulation at a cellular level, which is in coordination with the renal and branchial FAA absorption. We also revealed that the hagfish does possess the orthologs of the known osmoregulatory genes and that the transepithelial movement of inorganic ions in the hagfish gill and kidney is more complex than previously thought. These observations pose a challenge to the conventional view that the physiological features of hagfishes have been inherited from the last common ancestor of the extant vertebrates. [ABSTRACT FROM AUTHOR]

Identifying how the demands of migration are met at the level of gene expression is critical for understanding migratory physiology and can potentially reveal how migratory forms evolve from nonmigratory forms and vice versa. Among fishes, migration between freshwater and seawater (diadromy) requires considerable osmoregulatory adjustments, powered by the ion pump Na+, K+-ATPase (NKA) in the gills. Paralogs of the catalytic α-subunit of the pump (NKA α1a and α1b) are reciprocally upregulated in fresh- and seawater, a response known as paralog-switching, in gills of some diadromous species. We tested ontogenetic changes in NKA α-subunit paralog expression patterns, comparing pre-migrant and migrant alewife (Alosa pseudoharengus) sampled in their natal freshwater environment and after 24 h in seawater. In comparison to pre-migrants, juvenile out-migrants exhibited stronger paralog switching via greater downregulation of NKA α1a in seawater. We also tested microevolutionary changes in the response, exposing juvenile diadromous and landlocked alewife to freshwater (0 ppt) and seawater (30 ppt) for 2, 5, and 15 days. Diadromous and landlocked alewife exhibited salinity-dependent paralog switching, but levels of NKA α1b transcription were higher and the decrease in NKA α1a was greater after seawater exposure in diadromous alewife. Finally, we placed alewife α-subunit NKA paralogs in a macroevolutionary context. Molecular phylogenies show alewife paralogs originated independently of paralogs in salmonids and other teleosts. This study demonstrated that NKA paralog switching is tied to halohabitat profile and that duplications of the NKA gene provided the substrate for multiple, independent molecular solutions that support a diadromous life history. [ABSTRACT FROM AUTHOR]

While the transcriptional responses of yeast cells to a variety of individual stress conditions have been extensively studied, their responses to sequential stress conditions are less well understood. In this study, we present a comparative analysis of the transcriptome of an industrial strain and a laboratory strain exposed to different sequential stresses to establish a common response profile and also to identify genes whose expression is strain-dependent. Both strains induce pathways related to oxidative stress and osmotic stress response including those involved in glycerol synthesis, glutathione metabolism, and NADPH regeneration. Other genes that may also play an important role in this response include the transcription factor ADR1, SYM1, and most of the heat shock proteins. Induction of genes related to autophagy of mitochondria occurred only in the laboratory strain while possible stress tolerance factors, such as additional genes involved in glutathione production and detoxification, were uniformly enhanced only in the industrial strain. The analysis of the stress response to sequential stresses of two different strains allowed more precise identification of the response of yeast to complex environments. Identification of genes uniquely induced in the industrial strain can also be used to develop strategies to optimize various fermentation processes. [ABSTRACT FROM AUTHOR]

Freeze tolerance is a complex agronomic trait that is difficult to evaluate in the field because of year‐to‐year variation in weather. Discovering plant characteristics closely related to freeze tolerance would enable more effective selection for this important trait. To explore possible physiological mechanisms and search for useful characteristics related to freeze tolerance in winter barley, we conducted field and growth chamber experiments with seven freeze‐tolerant and seven freeze‐susceptible genotypes that exhibited contrasting winter survival in preliminary field screenings. In a 2‐year field experiment, malondialdehyde, proline and water‐soluble carbohydrate concentrations were measured during cold acclimation and deacclimation to investigate differences in osmoregulation and membrane stability between freeze‐tolerant and freeze‐sensitive genotypes. All parameters varied by sampling year, and significant differences between freeze tolerance groups were found mainly during cold deacclimation in the spring. In growth chamber experiments, the size of xylem vessels and stomates was measured with and without cold acclimation. Freeze‐tolerant genotypes had smaller xylem vessels and stomates than freeze‐sensitive genotypes with and without cold acclimation, and small stomatal length was associated with a small xylem vessel area. Thus, it may be possible to improve freeze tolerance in winter barley by selecting smaller xylem and stomate cells. This study also validated germplasms of winter barley with differential freeze tolerance for future projects on breeding for improving winter hardiness and on plant physiology and genetics in response to freezing stress. [ABSTRACT FROM AUTHOR]

Background: Drought is the most significant factor limiting maize production, given that maize is a crop with a high water demand. Therefore, studies investigating the mechanisms underlying the drought tolerance of maize are of great importance. There are no studies comparing drought tolerance among economically important subspecies of maize. This study aimed to reveal the differences between the physio-biochemical, enzymatic, and molecular mechanisms of drought tolerance in dent (Zea mays indentata), popcorn (Zea mays everta), and sugar (Zea mays saccharata) maize under control (no-stress), moderate, and severe drought stress. Methods: Three distinct irrigation regimes were employed to assess the impact of varying levels of drought stress on maize plants at the V14 growth stage. These included normal irrigation (80% field capacity), moderate drought (50% field capacity), and severe drought (30% field capacity). All plants were grown under controlled conditions. The following parameters were analyzed: leaf relative water content (RWC), loss of turgidity (LOT), proline (PRO) and soluble protein (SPR) contents, membrane durability index (MDI), malondialdehyde (MDA), and hydrogen peroxide (H2O2) content, the antioxidant enzyme activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT). Additionally, the expression of heat shock proteins (HSPs) was examined at the transcriptional and translational levels. Results: The effects of severe drought were more pronounced in sugar maize, which had a relatively high loss of RWC and turgor, membrane damage, enzyme activities, and HSP90 gene expression. Dent maize, which is capable of maintaining its RWC and turgor in both moderate and severe droughts, and employs its defense mechanism effectively by maintaining antioxidant enzyme activities at a certain level despite less MDA and H2O2 accumulation, exhibited relatively high drought tolerance. Despite the high levels of MDA and H2O2 in popcorn maize, the up-regulation of antioxidant enzyme activities and HSP70 gene and protein expression indicated that the drought coping mechanism is activated. In particular, the positive correlation of HSP70 with PRO and HSP90 with enzyme activities is a significant result for studies examining the relationships between HSPs and other stress response systems. The discrepancies between the transcriptional and translational findings provide an opportunity for more comprehensive investigations into the role of HSPs in stress conditions. [ABSTRACT FROM AUTHOR]

(1) The development and utilization of the vast saline–alkali land worldwide is an important way to solve the worsening food crisis. Eriocheir sinensis, due to its strong osmotic regulation capability and its characteristics of being suitable for culturing in alkaline water, has become a potential aquaculture species in saline–alkali water. The brain and heart are the key tissues for signal transduction and energy supply under environmental stress. (2) This study is the first to explore the synergistic regulatory molecular mechanism by integrated analysis on cerebral ganglion proteomics and heart metabolomics of Eriocheir sinensis under alkalinity stress. (3) The results indicate that the cerebral ganglion and heart of E. sinensis were closely related in response to acute alkalinity stress. The differential regulatory pathways mainly involved regulation of energy metabolism, amino acid metabolism, and homeostasis maintenance. Importantly, alkalinity stress induced the regulation of antioxidants and further adjusted longevity and rhythm in the cerebral ganglion and heart, reflecting that the cerebral ganglion and heart may be the key tissues for the survival of Eriocheir sinensis under an alkalinity environment. (4) This study provides a theoretical reference for research on the regulation mechanism of E. sinensis under alkalinity condition and contributes to the development of aquaculture in saline–alkali water. [ABSTRACT FROM AUTHOR]

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

In the last decades, non-native pink salmon Oncorhynchus gorbuscha successfully spread and occupied the rivers of the White Sea basin. We studied twenty-two blood parameters characterizing lipid metabolism, osmoregulation, energy exchange, and steroidogenesis at the crucial time point of pink salmon spawning migration: the passage of the critical salinity barrier in the estuary, preceding the migration upstream of the Umba River. The heterogeneity of biochemical parameters of non-native pink salmon predominantly was demonstrated in sexual dimorphism. We attributed this result to two main processes: maturation features and different timings of fish running from seawater to freshwater. Maturation features were characterized by differences between females and males in concentrations of estradiol-17β, triglycerides, and alanine aminotransferase. Both sexes had increased levels of cortisol due to changes in fish osmoregulation. Females had higher levels of cortisol, total protein, and calcium in comparison with males, which indicated that pink salmon females run to the river later than males. [ABSTRACT FROM AUTHOR]

Rhizome rot is a destructive soil-borne disease of Polygonatum kingianum and adversely affects the yield and sustenance of the plant. Understanding how the causal fungus Fusarium oxysporum infects P. kingianum may suggest effective control measures against rhizome rot. In germinating conidia of infectious F. oxysporum, expression of the zinc finger transcription factor gene Zfp1, consisting of two C2H2 motifs, was up-regulated. To characterize the critical role of ZFP1, we generated independent deletion mutants (zfp1) and complemented one mutant with a transgenic copy of ZFP1 (zfp1 tZFP1). Mycelial growth and conidial production of zfp1 were slower than those of wild type (ZFP1) and zfp1 tZFP1. Additionally, a reduced inhibition of growth suggested zfp1 was less sensitive to conditions promoting cell wall and osmotic stresses than ZFP1 and zfp1 tZFP1. Furthermore pathogenicity tests suggested a critical role for growth of zfp1 in infected leaves and rhizomes of P. kingianum. Thus ZFP1 is important for mycelial growth, conidiation, osmoregulation, and pathogenicity in P. kingianum. [ABSTRACT FROM AUTHOR]

As a widely used pesticide, abamectin could be a threat to nontarget organisms. In this study, the toxic mechanism of abamectin on osmoregulation in Procambarus clarkii was explored for the first time. The results of this study showed that with increasing abamectin concentration, the membrane structures of gill filaments were damaged, with changes in ATPase activities, transporter contents, biogenic amine contents, and gene expression levels. The results of this study indicated that at 0.2 mg/L abamectin, ion diffusion could maintain osmoregulation. At 0.4 mg/L abamectin, passive transport was inhibited due to damage to the membrane structures of gill filaments, and active transport needed to be enhanced for osmoregulation. At 0.6 mg/L abamectin, the membrane structures of gill filaments were seriously damaged, and the expression level of osmoregulation-related genes decreased, but the organisms were still mobilizing various transporters, ATPases, and biogenic amines to address abamectin stress. This study provided a theoretical basis for further study of the effects of contaminations in aquatic environment on the health of crustaceans. [ABSTRACT FROM AUTHOR]

Basil (Ocimum basilicum L.) is one of the most widely cultivated medicinal and aromatic species and the understanding of its physiological behavior under drought is of great importance for both basil producers and plant scientists. The aim of this study was to evaluate the physiological response of basil plants to different drought levels. This study found that drought significantly increased the activities of superoxide dismutase, guaiacol peroxidase, pyrogallol peroxidase and catalase, indicating that these enzymes play a prominent role in detoxification of reactive oxygen species and thus in plant drought tolerance. Exposure of basil plants to moderate and severe drought resulted in higher accumulation of proline and total phenolics and flavonoids, suggesting that basil plants under prolonged drought conditions tend to improve their drought tolerance by inducing the production of these compounds in leaves. Interestingly, mild drought did not negatively affect the photosynthetic pigment content as well as proline and total phenolic and flavonoid content in basil leaves as compared with control plants. In light of this fact, as well as the fact that the basil plants have the ability to produce protective macromolecules and antioxidants in high amounts in severe drought conditions, it can be concluded that basil plants tolerate drought conditions well. [ABSTRACT FROM AUTHOR]

Red blood cell (RBC) storage solutions have evolved significantly over the past decades to optimize the preservation of cell viability and functionality during hypothermic storage. This comprehensive review provides an in-depth analysis of the effects of various storage solutions and conditions on critical RBC parameters during refrigerated preservation. A wide range of solutions, from basic formulations such as phosphate-buffered saline (PBS), to advanced additive solutions (ASs), like AS-7 and phosphate, adenine, glucose, guanosine, saline, and mannitol (PAGGSM), are systematically compared in terms of their ability to maintain key indicators of RBC integrity, including adenosine triphosphate (ATP) levels, morphology, and hemolysis. Optimal RBC storage requires a delicate balance of pH buffering, metabolic support, oxidative damage prevention, and osmotic regulation. While the latest alkaline solutions enable up to 8 weeks of storage, some degree of metabolic and morphological deterioration remains inevitable. The impacts of critical storage conditions, such as the holding temperature, oxygenation, anticoagulants, irradiation, and processing methods, on the accumulation of storage lesions are also thoroughly investigated. Personalized RBC storage solutions, tailored to individual donor characteristics, represent a promising avenue for minimizing storage lesions and enhancing transfusion outcomes. Further research integrating omics profiling with customized preservation media is necessary to maximize post-transfusion RBC survival and functions. The continued optimization of RBC storage practices will not only enhance transfusion efficacy but also enable blood banking to better meet evolving clinical needs. [ABSTRACT FROM AUTHOR]

Water deficit significantly affects the growth and survival of young plants following transplantation. We performed morphophysiological and biochemical analyses on young yellow passion fruit (Passiflora edulis Sims) plants under well-watered and water-deficit irrigation regimes and pre-treated with three plant growth regulators (PGRs) application—an agrochemical composed of auxins, gibberellins, and cytokinins; salicylic acid (SA); and sodium nitroprusside (SNP), a nitric oxide donor—and a control group with no PGRs. Results showed significant damage by water restriction on biometric attributes; however, the application of PGRs mitigated these effects, reducing growth inhibition processes. In terms of water stress mitigation, differences were observed between PGRs, depending on the morphophysiological or biochemical characteristic. The effectiveness of SNP was higher than the other PGRs in preventing stomatal conductance reduction and maintaining CO2 assimilation, while the agrochemical was the most effective in preventing photosynthetic pigments content decrease. All PGRs promoted osmoregulation in plants subjected to water deficit, thus helping to preserve cell turgor. Furthermore, PGRs application attenuated oxidative stress, either by increasing antioxidant enzymes activity, or by preventing or decreasing the content of thiobarbituric acid-reactive substances, thus preventing lipid peroxidation. These findings suggest that the application of PGRs can be a useful strategy to improve young passion fruit plants tolerance to water restriction following transplantation. The multiple beneficial effects do not allow us to indicate the only one most effective PGR; however, a chemical constituents-related principal component analysis suggests that the agrochemical and SA are the most effective PGRs on mitigating water deficit stress. [ABSTRACT FROM AUTHOR]

Halophilic microorganisms play a crucial role in plant health and growth in salinity affected lands. The objective of this study was to evaluate the haloarchaeal diversity from the rhizosphere of halophytes and plant growth promoting abilities of these strains. The whole genome sequences of two haloarchaeal strains, Halorubrum lacusprofundi HL1RP11 and Halobacterium noricense NRS2HaP9, were analyzed, and genes related to plant growth promoting traits were identified. Phylogenetic analysis showed that archaeal strains of Halococcus, Halorubrum, Halobacterium and Natrinema were dominant in the rhizosphere of halophytes. More than 60% of the strains were positive for phosphate solubilization and IAA production. About 33% were siderophore producers. More than 40% of haloarchaeal strains showed the heavy metal resistance for Nickel, Cadmium, Chromium and Zinc at a concentration of 5 mM. Genes involved in plant growth promotion were identified through annotation. Gene clusters related to secondary metabolites including phenazine, siderophore production and terpene were also identified in this study. Our results suggested that these haloarchaeal strains can be used as an eco-friendly biofertilizer to improve growth and productivity in hypersaline environment. [ABSTRACT FROM AUTHOR]

Background: Microbial adaptation to salinity has been a classic inquiry in the field of microbiology. It has been demonstrated that microorganisms can endure salinity stress via either the "salt-in" strategy, involving inorganic ion uptake, or the "salt-out" strategy, relying on compatible solutes. While these insights are mostly based on laboratory-cultured isolates, exploring the adaptive mechanisms of microorganisms within natural salinity gradient is crucial for gaining a deeper understanding of microbial adaptation in the estuarine ecosystem. Results: Here, we conducted metagenomic analyses on filtered surface water samples collected from a typical subtropical short residence-time estuary and categorized them by salinity into low-, intermediate-, and high-salinity metagenomes. Our findings highlighted salinity-driven variations in microbial community composition and function, as revealed through taxonomic and Clusters of Orthologous Group (COG) functional annotations. Through metagenomic binning, 127 bacterial and archaeal metagenome-assembled genomes (MAGs) were reconstructed. These MAGs were categorized as stenohaline—specific to low-, intermediate-, or high-salinity—based on the average relative abundance in one salinity category significantly exceeding those in the other two categories by an order of magnitude. Those that did not meet this criterion were classified as euryhaline, indicating a broader range of salinity tolerance. Applying the Boruta algorithm, a machine learning-based feature selection method, we discerned important genomic features from the stenohaline bacterial MAGs. Of the total 12,162 COGs obtained, 40 were identified as important features, with the "inorganic ion transport and metabolism" COG category emerging as the most prominent. Furthermore, eight COGs were implicated in microbial osmoregulation, of which four were related to the "salt-in" strategy, three to the "salt-out" strategy, and one to the regulation of water channel activity. COG0168, annotated as the Trk-type K+ transporter related to the "salt-in" strategy, was ranked as the most important feature. The relative abundance of COG0168 was observed to increase with rising salinity across metagenomes, the stenohaline strains, and the dominant Actinobacteriota and Proteobacteria phyla. Conclusions: We demonstrated that salinity exerts influences on both the taxonomic and functional profiles of the microbial communities inhabiting the estuarine ecosystem. Our findings shed light on diverse salinity adaptation strategies employed by the estuarine microbial communities, highlighting the crucial role of the "salt-in" strategy mediated by Trk-type K+ transporters for microorganisms thriving under osmotic stress in the short residence-time estuary. 22YT9hkSS5Zn-gk-qyndrE Video Abstract [ABSTRACT FROM AUTHOR]

In this study, processing tomato (Solanum lycopersicum L.) 'Ligeer 87-5' was hydroponically cultivated under 100 mM NaCl to simulate salt stress. To investigate the impacts on ion homeostasis, osmotic regulation, and redox status in tomato seedlings, different endogenous levels of ascorbic acid (AsA) were established through the foliar application of 0.5 mM AsA (NA treatment), 0.25 mM lycorine (LYC, an inhibitor of AsA synthesis; NL treatment), and a combination of LYC and AsA (NLA treatment). The results demonstrated that exogenous AsA significantly increased the activities and gene expressions of key enzymes (L-galactono-1,4-lactone dehydrogenase (GalLDH) and L-galactose dehydrogenase (GalDH)) involved in AsA synthesis in tomato seedling leaves under NaCl stress and NL treatment, thereby increasing cellular AsA content to maintain its redox status in a reduced state. Additionally, exogenous AsA regulated multiple ion transporters via the SOS pathway and increased the selective absorption of K+, Ca2+, and Mg2+ in the aerial parts, reconstructing ion homeostasis in cells, thereby alleviating ion imbalance caused by salt stress. Exogenous AsA also increased proline dehydrogenase (ProDH) activity and gene expression, while inhibiting the activity and transcription levels of Δ1-pyrroline-5-carboxylate synthetase (P5CS) and ornithine-δ-aminotransferase (OAT), thereby reducing excessive proline content in the leaves and alleviating osmotic stress. LYC exacerbated ion imbalance and osmotic stress caused by salt stress, which could be significantly reversed by AsA application. Therefore, exogenous AsA application increased endogenous AsA levels, reestablished ion homeostasis, maintained osmotic balance, effectively alleviated the inhibitory effect of salt stress on tomato seedling growth, and enhanced their salt tolerance. [ABSTRACT FROM AUTHOR]

The escalating global temperatures associated with climate change are detrimental to plant growth and development, leading to significant reductions in crop yields worldwide. Our research demonstrates that salicylic acid (SA), a phytohormone known for its growth-promoting properties, is crucial in enhancing heat tolerance in cotton (Gossypium hirsutum). This enhancement is achieved through modifications in various biochemical, physiological, and growth parameters. Under heat stress, cotton plants typically show significant growth disturbances, including leaf wilting, stunted growth, and reduced biomass. However, priming cotton plants with 1 mM SA significantly mitigated these adverse effects, evidenced by increases in shoot dry mass, leaf-water content, and chlorophyll concentrations in the heat-stressed plants. Heat stress also prompted an increase in hydrogen peroxide levels—a key reactive oxygen species—resulting in heightened electrolyte leakage and elevated malondialdehyde concentrations, which indicate severe impacts on cellular membrane integrity and oxidative stress. Remarkably, SA treatment significantly reduced these oxidative stresses by enhancing the activities of critical antioxidant enzymes, such as catalase, glutathione S-transferase, and ascorbate peroxidase. Additionally, the elevated levels of total soluble sugars in SA-treated plants enhanced osmotic regulation under heat stress. Overall, our findings reveal that SA-triggered protective mechanisms not only preserve photosynthetic pigments but also ameliorate oxidative stress and boost plant resilience in the face of elevated temperatures. In conclusion, the application of 1 mM SA is highly effective in enhancing heat tolerance in cotton and is recommended for field trials before being commercially used to improve crop resilience under increasing global temperatures. [ABSTRACT FROM AUTHOR]

The holly Ilex dabieshanensis K. Yao & M. B. Deng, a tree endemic to the Dabieshan Mountains region in China, is a commonly used landscaping plant. Like other crops, its growth is affected by salt stress. The molecular mechanism underlying salt tolerance in holly is still unclear. In this study, we used NaCl treatment and RNA sequencing (RNA-seq) at different times to identify the salt stress response genes of holly. A total of 4775 differentially expressed genes (DEGs) were identified. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of the DEGs obtained at different salt treatment times (3, 6, 9, 12, and 24 h), as compared to control (ck, 0 h), showed that plant hormone signal transduction and carotenoid biosynthesis were highly enriched. The mechanism by which holly responds to salt stress involves many plant hormones, among which the accumulation of abscisic acid (ABA) and its signal transduction may play an important role. In addition, ion homeostasis, osmotic metabolism, accumulation of antioxidant enzymes and nonenzymatic antioxidant compounds, and transcription factors jointly regulate the physiological balance in holly, providing important guarantees for its growth and development under conditions of salt stress. These results lay the foundation for studying the molecular mechanisms of salt tolerance in holly and for the selection of salt-tolerant varieties. [ABSTRACT FROM AUTHOR]

Background: The climatic changes crossing the world menace the green life through limitation of water availability. The goal of this study was to determine whether Moringa oleifera Lam. trees cultivated under Tunisian arid climate, retain their tolerance ability to tolerate accentuated environmental stress factors such as drought and salinity. For this reason, the seeds of M. oleifera tree planted in Bouhedma Park (Tunisian arid area), were collected, germinated, and grown in the research area at the National Institute of Research in Rural Engineering, Waters and Forests (INRGREF) of Tunis (Tunisia). The three years aged trees were exposed to four water-holding capacities (25, 50, 75, and 100%) for 60 days to realise this work. Results: Growth change was traduced by the reduction of several biometric parameters and fluorescence (Fv/Fm) under severe water restriction (25 and 50%). Whereas roots presented miraculous development in length face to the decrease of water availability (25 and 50%) in their rhizospheres. The sensitivity to drought-induced membrane damage (Malondialdehyde (MDA) content) and reactive oxygen species (ROS) liberation (hydrogen peroxide (H2O2) content) was highly correlated with ROS antiradical scavenging (ferric reducing antioxidant power (FRAP) and (2, 2'-diphenyl-1-picrylhydrazyle (DPPH)), phenolic components and osmolytes accumulation. The drought stress tolerance of M. oleifera trees was associated with a dramatic stimulation of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX), and glutathione peroxidase (GPX) activities. Conclusion: Based on the several strategies adopted, integrated M. oleifera can grow under drought stress as accentuated adverse environmental condition imposed by climate change. [ABSTRACT FROM AUTHOR]

Introduction: Soil salinization poses a significant environmental challenge affecting plant growth and agricultural sustainability. This study explores the potential of salt-tolerant endophytes to mitigate the adverse effects of soil salinization, emphasizing their impact on the development and resistance of Arachis hypogaea L. (peanuts). Methods: The diversity of culturable plant endophytic bacteria associated with Miscanthus lutarioriparius was investigated. The study focused on the effects of Bacillus tequilensis, Staphylococcus epidermidis, and Bacillus siamensis on the development and germination of A. hypogaea seeds in pots subjected to high NaCl concentrations (200 mM L-1). Results: Under elevated NaCl concentrations, the inoculation of endophytes significantly (p < 0.05) enhanced seedling germination and increased the activities of enzymes such as Superoxide dismutase, catalase, and polyphenol oxidase, while reducing malondialdehyde and peroxidase levels. Additionally, endophyte inoculation resulted in increased root surface area, plant height, biomass contents, and leaf surface area of peanuts under NaCl stress. Transcriptome data revealed an augmented defense and resistance response induced by the applied endophyte (B. tequilensis, S. epidermidis, and B. siamensis) strain, including upregulation of abiotic stress related mechanisms such as fat metabolism, hormones, and glycosyl inositol phosphorylceramide (Na+ receptor). Na+ receptor under salt stress gate Ca2+ influx channels in plants. Notably, the synthesis of secondary metabolites, especially genes related to terpene and phenylpropanoid pathways, was highly regulated. Conclusion: The inoculated endophytes played a possible role in enhancing salt tolerance in peanuts. Future investigations should explore protein--protein interactions between plants and endophytes to unravel the mechanisms underlying endophyte-mediated salt resistance in plants. [ABSTRACT FROM AUTHOR]

Physiological and morphological acclimation capacities of black‐chinned tilapia, Sarotherodon melanotheron were studied from fish to gill cell level when fish are maintained in freshwater, seawater, and hypersaline conditions. Fish osmoregulatory capacity, gill ionocyte morphology, osmo‐respiratory compromise, O2 consumption rate, branchial antioxidative defense, and cell apoptosis were considered. Captive juvenile tilapias were maintained in controlled freshwater conditions (FW: 0.4 ppt; 12 mOsm kg−1) or gradually transferred to seawater (SW: 32 ppt; 958 mOsm kg−1) and concentrated SW (cSW: 65 ppt; 1920 mOsm kg−1). After 15 days in these conditions, blood osmolality and chloride ion concentration were determined. Gill ionocyte density and morphology were measured using immunolabelled histological sections to specifically detect the sodium pump (NKA). Gill osmo‐respiratory compromise was also calculated along with oxygen consumption rates from normoxic to hypoxic conditions from excised gills (indirect respirometry). Finally, catalase and caspase 3/7activities were recorded from gill extracts. Results indicate that elevated salinity induces an osmotic imbalance and a profound morphological change with proliferating and hypertrophied ionocytes. This thickening of the gill interlamellar cell mass and the shortening of the lamellae induce a reduced osmo‐respiratory ratio and reduced respiratory capacity under both normoxic and hypoxic conditions. Although salinity changes do not affect one of the major antioxidative defense mechanism, it strongly affects apoptosis that appears the most elevated in SW. However, in freshwater condition, fish can maintain their osmotic balance with a low ionocyte density, a low apoptotic level and a drastically reduced O2 consumption in normoxic condition that is maintained in hypoxia. Therefore, S. melanotheron presents the typical functional remodeling due to environmental salinity changes ranging from FW to SW. However, elevated seawater induces major cellular stress inducing a profound gill morphofunctional dysfunctioning. While cell apoptosis is reduced, ionocyte proliferation is massively increased with impaired osmotic regulation and reduced O2 consumption both in normoxic and hypoxic conditions. [ABSTRACT FROM AUTHOR]

Prohexadione calcium (EA) and gibberellin (GA) are two different types of plant growth regulators that have different effects on the regulation of plant development. The objective of this study was to evaluate the impacts of EA and GA on rice plant growth, development and morph-physiological traits in two rice varieties: 'Huang Huazhan' and 'Guang Hong 3'. At the three-leaf seedling stage, the plants were treated with 50 mM NaCl 24 h after foliar application of EA (100 mg·L−1) and GA (1 mg·L−1). Data on morphological indexes, osmotic regulators and antioxidant activities were compared with the treatment of EA and GA on the 4th, 7th, 10th and 13th days after NaCl stress. Our data analysis showed that NaCl stress inhibited the leaf area growth of rice seedlings, altered the microstructure and disrupted the antioxidant system, ion uptake and transport balance. The significant increase in malondialdehyde (MDA) content and superoxide anion production rate (O2 · ¯) indicated that NaCl stress caused a severe oxidative stress response to rice seedlings. Treatment with EA and GA activated the antioxidant system under NaCl stress, significantly elevated superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities and suppressed the increase in MDA content and the O2 · ¯ production rate. Under NaCl stress, EA and GA treatments improved the osmoregulatory balance, significantly increased soluble protein and proline contents and maintained lower Na+/K+ levels. EA and GA treatments significantly increased the K+ and Ca2+ contents, thereby maintaining ionic balance, which was favorable for maintaining the growth of rice seedlings. In this study, moth plant growth regulators maintained the growth and development of rice seedlings under NaCl stress by inducing an increase in osmoregulation and antioxidant levels, reducing the degree of membrane damage and regulating the selective uptake of ions by rice seedlings. Current findings also clarified that foliar application of EA was more effective than GA in three-leaf seedlings by enhancing the morph-physiological and antioxidant parameters under NaCl stress. [ABSTRACT FROM AUTHOR]

The freshwater‐seawater mixing zone ("interface") is affected by tides, seawater intrusion, submarine groundwater discharge and aquifer heterogeneities. Our current understanding is based primarily on theoretical studies involving numerical simulation and sand‐tank experimentation, with limited field analyses of interface characteristics in coastal aquifers that serve as important freshwater reservoirs. The most common field evidence for interface characteristics is derived from electrical conductivity (EC) profiles, often obtained from long‐screen wells. However, the EC profiles from long‐screen wells have been assessed previously using only simple statistics like the depth to 50% of seawater concentration. This study introduces a methodology for characterizing EC profiles using curve fitting and objective assessment of multiple interface attributes, with application to 170 EC profiles from the Lower Burdekin Delta, Australia. The adopted fitting function showed an excellent match (mean R2 = 0.99). Fitting parameters were linked to the curvatures of transitions from fresh to brackish water and from brackish water to seawater, the elevation and gradient of the mid‐salinity value, and the thickness of the mixing zone. Field EC profiles showed approximately linear relationships between head changes averaged over the previous 5 months and the elevation of 5 mS/cm isochlor for some wells. The slope of this relationship was approximately one, which is approximately 1/40th of the value arising from the Ghyben‐Herzberg relation. The framework for characterizing salinity profiles presented in this article offers a new, objective approach for investigating the interface, providing future studies with a technique for examining relationships between interface behavior and key controlling forces. Key Points: Framework for characterizing coastal aquifer salinity profiles and mixing zone characteristics is presentedOne hundred and seventy salinity profiles well matched to fitting function, with fitting parameters linked to five key interface attributesMixing zone rise time‐lagged head drop in some wells, with smaller mixing zone changes relative to the Ghyben‐Herzberg ratio [ABSTRACT FROM AUTHOR]

To explore the role of penconazole (PEN) and potassium (K) in controlling reactive oxygen species (ROS) production, accumulation of osmotically active substances and antioxidant defense system in wheat plants under drought conditions, an experiment was conducted. Two cultivars of wheat plant (Moghan and Sirvan) were treated by different PEG concentrations (0, 5, 10 and 15%) without or with PEN (15 mg L−1) and K (1 M). Drought caused damaging effects on growth attributes in both cultivar and Sirvan cultivar was more sensitive to drought stress. Enhanced levels of the hydrogen peroxide (H2O2) and malondialdehyde (MDA) were evident that drought stress induced oxidative stress in both cultivars. The activities of antioxidant enzymes were significantly declined under drought conditions. Drought stress enhanced accumulation of proline and soluble sugar as osmotic substance in both cultivars. In contracts to Sirvan cultivar, the content of antioxidant metabolites (total phenol, flavonol and anthocyanin) augmented under drought conditions. PEN and K application improved growth and regulated acclimation responses in wheat plants. Reduction in H2O2 and lipid peroxidation (MDA content) by PEN and K showed that PEN and K aided to alleviate drought-trigged oxidative stress in wheat plants. Noteworthily, soluble sugar dominated than proline in the osmotic regulation in stressed plants treated with PEN and K. PEN and K strengthened the enzymatic and non-enzymatic antioxidant systems in wheat plants. In summary, PEN and K provided a better defense to wheat plants against drought stress and positive impacts of PEN and K were related to improved physiological and metabolic processes under drought conditions. [ABSTRACT FROM AUTHOR]

Due to high-density farming methods and poor farming environments, freshwater fish often have poor muscle texture and a fishy odor before marketing, which impacts consumer acceptance. Short-term low-salinity seawater treatment of freshwater fish before marketing has been found to improve the quality of the fish, but the mechanisms underlying this phenomenon have not yet been revealed. In this study, metabolomics technique was used based on gas chromatography-mass spectrometry (GC–MS) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) to screen different metabolites and predict potential metabolic pathways after treatment with low-salinity seawater. The results showed that 3838 metabolites were presented in all of the carp samples, while 62 and 64 differential metabolites were found in the comparative groups (FW, SW, and CK represented freshwater, seawater and non-transient group, respectively). Additionally, 25 and 26 metabolic pathways were enriched from these groups. Glutaric acid, PC, and creatinine might be potential biomarkers. Seawater aquaculture significantly altered the lipid metabolism, nucleotide metabolism, and amino acid metabolism of carp, enhancing its freshness and having a significant impact on its quality. This study provided insights into the metabolic changes in carp under different rearing conditions and also served as a theoretical basis for salinity treatment before freshwater fish are brought to the market. [ABSTRACT FROM AUTHOR]

Enterocytozoon hepatopenaei (EHP) is a fungal pathogen that causes hepatopancreatic microsporidiosis (HPM) in shrimp, resulting in significant economic losses for the shrimp culture industry. Although the impact of EHP on hormonal regulation in shrimp has been seldom examined, it remains a crucial area of study. In this paper, we analyzed the transcriptomic data of the hepatopancreas of EHP-infected and uninfected shrimp to explore the effect of EHP on hormonal regulation. Our results identified 157 differentially expressed genes (DEGs), of which 32 genes were upregulated and 125 were downregulated. Through gene ontology (GO) and KEGG analyses of hormone regulation-related DEGs, we identified eight genes, six of which were associated with the regulation of molting and growth, one with immunity, and one with osmotic pressure regulation. The up- and downregulated pathways were mostly related to molting and growth regulation, including EGFR tyrosine kinase inhibitor resistance, thyroid hormone signaling pathway, and steroid hormone biosynthesis. Ten genes were selected randomly for qRT-PCR, and results confirmed the findings of transcriptome sequencing. This study provides essential insights into the molecular mechanisms through which EHP affects hormonal regulation in shrimp and serves as a basis for further research to control HPM. [ABSTRACT FROM AUTHOR]

Aspergillus cristatus is a crucial edible fungus used in tea fermentation. In the industrial fermentation process, the fungus experiences a low to high osmotic pressure environment. To explore the law of material metabolism changes during osmotic pressure changes, NaCl was used here to construct different osmotic pressure environments. Liquid chromatography–mass spectrometry (LC–MS) combined with multivariate analysis was performed to analyze the distribution and composition of A. cristatus under different salt concentrations. At the same time, the in vitro antioxidant activity was evaluated. The LC–MS metabolomics analysis revealed significant differences between three A. cristatus mycelium samples grown on media with and without NaCl concentrations of 8% and 18%. The contents of gibberellin A3, A124, and prostaglandin A2 related to mycelial growth and those of arabitol and fructose-1,6-diphosphate related to osmotic pressure regulation were significantly reduced at high NaCl concentrations. The biosynthesis of energy-related pantothenol and pantothenic acid and antagonism-related fluvastatin, aflatoxin, and alternariol significantly increased at high NaCl concentrations. Several antioxidant capacities of A. cristatus mycelia were directly related to osmotic pressure and exhibited a significant downward trend with an increase in environmental osmotic pressure. The aforementioned results indicate that A. cristatus adapts to changes in salt concentration by adjusting their metabolite synthesis. At the same time, a unique set of strategies was developed to cope with high salt stress, including growth restriction, osmotic pressure balance, oxidative stress response, antioxidant defense, and survival competition. [ABSTRACT FROM AUTHOR]