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1.
Biochem Biophys Res Commun ; 717: 150049, 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-38714014

RESUMO

Acquired osmotolerance induced by initial exposure to mild salt stress is widespread across Arabidopsis thaliana ecotypes, but the mechanism underlying it remains poorly understood. To clarify it, we isolated acquired osmotolerance-deficient 1 (aod1), a mutant highly sensitive to osmotic stress, from ion-beam-irradiated seeds of Zu-0, an ecotype known for its remarkably high osmotolerance. Aod1 showed growth inhibition with spotted necrotic lesions on the rosette leaves under normal growth conditions on soil. However, its tolerance to salt and oxidative stresses was similar to that of the wild type (WT). Genetic and genome sequencing analyses suggested that the gene causing aod1 is identical to CONSTITUTIVELY ACTIVATED CELL DEATH 1 (CAD1). Complementation with the WT CAD1 gene restored the growth and osmotolerance of aod1, indicating that mutated CAD1 is responsible for the observed phenotypes in aod1. Although CAD1 is known to act as a negative regulator of immune response, transcript levels in the WT increased in response to osmotic stress. Aod1 displayed enhanced immune response and cell death under normal growth conditions, whereas the expression profiles of osmotic response genes were comparable to those of the WT. These findings suggest that autoimmunity in aod1 is detrimental to osmotolerance. Overall, our results suggest that CAD1 negatively regulates immune responses under osmotic stress, contributing to osmotolerance in Arabidopsis.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Pressão Osmótica , Arabidopsis/genética , Arabidopsis/imunologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Mutação , Imunidade Vegetal/genética
2.
Sci Rep ; 14(1): 9978, 2024 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-38693252

RESUMO

An extremely important oil crop in the world, Helianthus annuus L. is one of the world's most significant members of the Asteraceae family. The rate and extent of seed germination and agronomic features are consistently affecting  by temperature (T) and changes in water potential (ψ). A broad hydrothermal time model with T and ψ components could explain sunflower responses over suboptimal T and ψ. A lab experiment was performed using the HTT model to discover both T and ψ and their interactive effects on sunflower germination and also to figure  out the cardinal Ts values. The sunflower seeds were germinated at temperatures (15 °C, 20 °C, 25 °C and 30 °C); each Ts had five constant ψs of 0, 0.3, 0.6, 0.9, and 1.2 MPa via PEG 6000 as osmotic stress inducer. The results revealed that highest germination index was found in seed grown at 20 °C in distilled water (0 MPa) and the lowest at 30 °C with osmotic stress of (- 1.2 MPa). The highest value of germination rate index was found in seed grown at 20 °C in distilled water (0 MPa) and the lowest at 15 °C with an osmotic stress of (- 1.2 MPa). In conclusion, water potential, temperature, and their interactions have a considerable impact on seed germination rate, and other metrics (GI, SVI-I, GRI, GE, SVI-II, and MGT). Seeds sown  at 20 °C with zero water potential showed high germination metrics such as GE, GP, GRI, and T50%. The maximum value to TTsub noted at 30 °C in - 0.9 MPa osmotic stress and the minimum value was calculated at 15 °C in - 1.2 MPa osmotic stress. The result of TTsupra recorded highest at 15 °C in  controlled group (0 MPa). Moreover, θH was  highest at 30 °C in controlled condition (0 MPa) and minimum value was observed at  20 °C under - 1.2 MPa osmotic stress. The value of θHTT were  maximum at  30 °C in controlled group (0 MPa) and minimum value was  recorded at 15 °C under - 1.2 MPa osmotic potential. The base, optimum and ceiling temperatures for sunflower germination metrics in this experiment were noted  6.8, 20 and 30 °C respectively.


Assuntos
Germinação , Helianthus , Pressão Osmótica , Sementes , Temperatura , Helianthus/crescimento & desenvolvimento , Helianthus/fisiologia , Sementes/crescimento & desenvolvimento , Água , Modelos Teóricos
3.
Proc Natl Acad Sci U S A ; 121(22): e2318412121, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38781205

RESUMO

Lysosomes are central players in cellular catabolism, signaling, and metabolic regulation. Cellular and environmental stresses that damage lysosomal membranes can compromise their function and release toxic content into the cytoplasm. Here, we examine how cells respond to osmotic stress within lysosomes. Using sensitive assays of lysosomal leakage and rupture, we examine acute effects of the osmotic disruptant glycyl-L-phenylalanine 2-naphthylamide (GPN). Our findings reveal that low concentrations of GPN rupture a small fraction of lysosomes, but surprisingly trigger Ca2+ release from nearly all. Chelating cytoplasmic Ca2+ makes lysosomes more sensitive to GPN-induced rupture, suggesting a role for Ca2+ in lysosomal membrane resilience. GPN-elicited Ca2+ release causes the Ca2+-sensor Apoptosis Linked Gene-2 (ALG-2), along with Endosomal Sorting Complex Required for Transport (ESCRT) proteins it interacts with, to redistribute onto lysosomes. Functionally, ALG-2, but not its ESCRT binding-disabled ΔGF122 splice variant, increases lysosomal resilience to osmotic stress. Importantly, elevating juxta-lysosomal Ca2+ without membrane damage by activating TRPML1 also recruits ALG-2 and ESCRTs, protecting lysosomes from subsequent osmotic rupture. These findings reveal that Ca2+, through ALG-2, helps bring ESCRTs to lysosomes to enhance their resilience and maintain organelle integrity in the face of osmotic stress.


Assuntos
Cálcio , Complexos Endossomais de Distribuição Requeridos para Transporte , Lisossomos , Pressão Osmótica , Lisossomos/metabolismo , Humanos , Cálcio/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Membranas Intracelulares/metabolismo , Células HeLa , Canais de Potencial de Receptor Transitório/metabolismo , Canais de Potencial de Receptor Transitório/genética , Proteínas de Ligação ao Cálcio , Proteínas Reguladoras de Apoptose
4.
Reprod Fertil Dev ; 362024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38769680

RESUMO

Context Conventional sperm quality tests may not be sufficient to predict the fertilising ability of a given ejaculate; thus, rapid, reliable and sensitive tests are necessary to measure sperm function. Aims This study sought to address whether a cluster analysis approach based on flow cytometry variables could provide more information about sperm function. Methods Spermatozoa were exposed to either isotonic (300mOsm/kg) or hypotonic (180mOsm/kg) media for 5 and 20min, and were then stained with SYBR14 and propidium iodide (PI). Based on flow cytometry dot plots, spermatozoa were classified as either viable (SYBR14+ /PI- ) or with different degrees of plasma membrane alteration (SYBR14+ /PI+ and SYBR14- /PI+ ). Moreover, individual values of electronic volume (EV), side scattering (SS), green (FL1) and red (FL3) fluorescence were recorded and used to classify sperm cells through cluster analysis. Two strategies of this approach were run. The first one was based on EV and the FL3/FL1 quotient, and the second was based on EV, SS and the FL3/FL1 quotient. Key results The two strategies led to the identification of more than three sperm populations. In the first strategy, EV did not differ between membrane-intact and membrane-damaged sperm, but it was significantly (P P P Conclusions Cluster analysis based on flow cytometry variables provides more information about sperm function than conventional assessment does. Implications Combining flow cytometry with cluster analysis is a more robust approach for sperm evaluation.


Assuntos
Citometria de Fluxo , Pressão Osmótica , Análise do Sêmen , Espermatozoides , Citometria de Fluxo/métodos , Masculino , Espermatozoides/fisiologia , Análise do Sêmen/métodos , Análise do Sêmen/veterinária , Análise por Conglomerados , Membrana Celular/fisiologia , Motilidade dos Espermatozoides/fisiologia , Animais
5.
Arch Microbiol ; 206(6): 270, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38767668

RESUMO

Candida tropicalis is a human pathogen and one of the most prevalent non-Candida albicans Candida (NCAC) species causing invasive infections. Azole antifungal resistance in C. tropicalis is also gradually increasing with the increasing incidence of infections. The pathogenic success of C. tropicalis depends on its effective response in the host microenvironment. To become a successful pathogen, cellular metabolism, and physiological status determine the ability of the pathogen to counter diverse stresses inside the host. However, to date, limited knowledge is available on the impact of carbon substrate metabolism on stress adaptation and azole resistance in C. tropicalis. In this study, we determined the impact of glucose, fructose, and sucrose as the sole carbon source on the fluconazole resistance and osmotic (NaCl), oxidative (H2O2) stress adaptation in C. tropicalis clinical isolates. We confirmed that the abundance of carbon substrates influences or increases drug resistance and osmotic and oxidative stress tolerance in C. tropicalis. Additionally, both azole-resistant and susceptible isolates showed similar stress adaptation phenotypes, confirming the equal efficiency of becoming successful pathogens irrespective of drug susceptibility profile. To the best of our knowledge, our study is the first on C. tropicalis to demonstrate the direct relation between carbon substrate metabolism and stress tolerance or drug resistance.


Assuntos
Antifúngicos , Candida tropicalis , Carbono , Farmacorresistência Fúngica , Fluconazol , Testes de Sensibilidade Microbiana , Estresse Oxidativo , Candida tropicalis/efeitos dos fármacos , Candida tropicalis/fisiologia , Antifúngicos/farmacologia , Humanos , Fluconazol/farmacologia , Carbono/metabolismo , Candidíase/microbiologia , Pressão Osmótica , Glucose/metabolismo , Sacarose/metabolismo , Sacarose/farmacologia , Peróxido de Hidrogênio/farmacologia , Peróxido de Hidrogênio/metabolismo , Frutose/metabolismo , Frutose/farmacologia , Estresse Fisiológico
6.
J Phys Chem B ; 128(20): 4911-4921, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38736363

RESUMO

To combat surging multidrug-resistant Gram-negative bacterial infections, better strategies to improve the efficacy of existing drugs are critical. Because the dual membrane cell envelope is the first line of defense for these bacteria, it is crucial to understand the permeation properties of the drugs through it. Our recent study shows that isosmotic conditions prevent drug permeation inside Gram-negative bacteria, Escherichia coli, while hypoosmotic stress enhances the process. Here, we unravel the reason behind such differential drug penetration. Specifically, we dissect the roles of electrostatic screening and low membrane permeability in the penetration failure of drugs under osmotically balanced conditions. We compare the transport of a quaternary ammonium compound malachite green in the presence of an electrolyte (NaCl) and a wide variety of commonly used organic osmolytes, e.g., sucrose, proline, glycerol, sorbitol, and urea. These osmolytes of different membrane permeability (i.e., nonpermeable sucrose and NaCl, freely permeable urea and glycerol, and partially permeable proline and sorbitol) clarify the role of osmotic stress in cell envelope permeability. The results showcase that under balanced osmotic conditions, drug molecules fail to penetrate inside E. coli cells because of low membrane permeabilities and not because of electrostatic screening imposed by the osmolytes. Contribution of the electrostatic interactions, however, cannot be completely overruled as at osmotically imbalanced conditions, drug transport across the bacterial subcellular compartments is found to be dependent on the osmolytes used.


Assuntos
Permeabilidade da Membrana Celular , Escherichia coli , Pressão Osmótica , Eletricidade Estática , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Transporte Biológico , Antibacterianos/química , Antibacterianos/farmacologia , Antibacterianos/metabolismo , Membrana Celular/metabolismo , Membrana Celular/química
7.
J Cell Mol Med ; 28(10): e18409, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38769917

RESUMO

Farnesoid X receptor (FXR), a ligand-activated transcription factor, plays an important role in maintaining water homeostasis by up-regulating aquaporin 2 (AQP2) expression in renal medullary collecting ducts; however, its role in the survival of renal medullary interstitial cells (RMICs) under hypertonic conditions remains unclear. We cultured primary mouse RMICs and found that the FXR was expressed constitutively in RMICs, and that its expression was significantly up-regulated at both mRNA and protein levels by hypertonic stress. Using luciferase and ChIP assays, we found a potential binding site of nuclear factor kappa-B (NF-κB) located in the FXR gene promoter which can be bound and activated by NF-κB. Moreover, hypertonic stress-induced cell death in RMICs was significantly attenuated by FXR activation but worsened by FXR inhibition. Furthermore, FXR increased the expression and nuclear translocation of hypertonicity-induced tonicity-responsive enhance-binding protein (TonEBP), the expressions of its downstream target gene sodium myo-inositol transporter (SMIT), and heat shock protein 70 (HSP70). The present study demonstrates that the NF-κB/FXR/TonEBP pathway protects RMICs against hypertonic stress.


Assuntos
Medula Renal , NF-kappa B , Transdução de Sinais , Animais , NF-kappa B/metabolismo , Camundongos , Medula Renal/metabolismo , Medula Renal/citologia , Pressão Osmótica , Aquaporina 2/metabolismo , Aquaporina 2/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Masculino , Camundongos Endogâmicos C57BL , Proteínas de Choque Térmico HSP70/metabolismo , Proteínas de Choque Térmico HSP70/genética , Regiões Promotoras Genéticas , Células Cultivadas , Regulação da Expressão Gênica , Simportadores/metabolismo , Simportadores/genética , Receptores Citoplasmáticos e Nucleares
8.
Cell Stem Cell ; 31(5): 640-656.e8, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38701758

RESUMO

Post-implantation, the pluripotent epiblast in a human embryo forms a central lumen, paving the way for gastrulation. Osmotic pressure gradients are considered the drivers of lumen expansion across development, but their role in human epiblasts is unknown. Here, we study lumenogenesis in a pluripotent-stem-cell-based epiblast model using engineered hydrogels. We find that leaky junctions prevent osmotic pressure gradients in early epiblasts and, instead, forces from apical actin polymerization drive lumen expansion. Once the lumen reaches a radius of ∼12 µm, tight junctions mature, and osmotic pressure gradients develop to drive further growth. Computational modeling indicates that apical actin polymerization into a stiff network mediates initial lumen expansion and predicts a transition to pressure-driven growth in larger epiblasts to avoid buckling. Human epiblasts show transcriptional signatures consistent with these mechanisms. Thus, actin polymerization drives lumen expansion in the human epiblast and may serve as a general mechanism of early lumenogenesis.


Assuntos
Actinas , Camadas Germinativas , Pressão Osmótica , Polimerização , Humanos , Actinas/metabolismo , Camadas Germinativas/metabolismo , Camadas Germinativas/citologia , Modelos Biológicos , Junções Íntimas/metabolismo
9.
BMC Microbiol ; 24(1): 165, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38745279

RESUMO

Globally, drought stress poses a significant threat to crop productivity. Improving the drought tolerance of crops with microbial biostimulants is a sustainable strategy to meet a growing population's demands. This research aimed to elucidate microbial biostimulants' (Plant Growth Promoting Rhizobacteria) role in alleviating drought stress in oil-seed crops. In total, 15 bacterial isolates were selected for drought tolerance and screened for plant growth-promoting (PGP) attributes like phosphate solubilization and production of indole-3-acetic acid, siderophore, hydrogen cyanide, ammonia, and exopolysaccharide. This research describes two PGPR strains: Acinetobacter calcoaceticus AC06 and Bacillus amyloliquefaciens BA01. The present study demonstrated that these strains (AC06 and BA01) produced abundant osmolytes under osmotic stress, including proline (2.21 and 1.75 µg ml- 1), salicylic acid (18.59 and 14.21 µg ml- 1), trehalose (28.35 and 22.74 µg mg- 1 FW) and glycine betaine (11.35 and 7.74 mg g- 1) respectively. AC06 and BA01 strains were further evaluated for their multifunctional performance by inoculating in Arachis hypogaea L. (Groundnut) under mild and severe drought regimes (60 and 40% Field Capacity). Inoculation with microbial biostimulants displayed distinct osmotic-adjustment abilities of the groundnut, such as growth parameters, plant biomass, photosynthetic pigments, relative water content, proline, and soluble sugar in respective to control during drought. On the other hand, plant sensitivity indexes such as electrolyte leakage and malondialdehyde (MDA) contents were decreased as well as cooperatively conferred plant drought tolerance by induced alterations in stress indicators such as catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD). Thus, Acinetobacter sp. AC06 and Bacillus sp. BA01 can be considered as osmolyte producing microbial biostimulants to simultaneously induce osmotic tolerance and metabolic changes in groundnuts under drought stress.


Assuntos
Arachis , Secas , Estresse Fisiológico , Arachis/microbiologia , Arachis/crescimento & desenvolvimento , Arachis/metabolismo , Arachis/fisiologia , Prolina/metabolismo , Bacillus amyloliquefaciens/metabolismo , Bacillus amyloliquefaciens/fisiologia , Microbiologia do Solo , Pressão Osmótica , Betaína/metabolismo , Ácidos Indolacéticos/metabolismo , Ácido Salicílico/metabolismo , Acinetobacter/metabolismo , Acinetobacter/crescimento & desenvolvimento , Acinetobacter/fisiologia , Cianeto de Hidrogênio/metabolismo , Trealose/metabolismo
10.
Arch Microbiol ; 206(6): 260, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38744718

RESUMO

Campylobacter jejuni is known to enter a viable but non-culturable (VBNC) state when exposed to environmental stresses. Microarray and quantitative real-time polymerase chain reaction (qPCR) analyses were performed to elucidate the genes related to the induction of the VBNC state. The C. jejuni NCTC11168 strain was cultured under low-temperature or high-osmotic stress conditions to induce the VBNC state. mRNA expression in the VBNC state was investigated using microarray analysis, and the gene encoding peptidoglycan-associated lipoprotein, Pal, was selected as the internal control gene using qPCR analysis and software. The three genes showing particularly large increases in mRNA expression, cj1500, cj1254, and cj1040, were involved in respiration, DNA repair, and transporters, respectively. However, formate dehydrogenase encoded by cj1500 showed decreased activity in the VBNC state. Taken together, C. jejuni actively changed its mRNA expression during induction of the VBNC state, and protein activities did not always match the mRNA expression levels.


Assuntos
Proteínas de Bactérias , Campylobacter jejuni , Regulação Bacteriana da Expressão Gênica , Campylobacter jejuni/genética , Campylobacter jejuni/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Viabilidade Microbiana , Pressão Osmótica , Estresse Fisiológico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Perfilação da Expressão Gênica
11.
Elife ; 122024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38568203

RESUMO

Natural environments of living organisms are often dynamic and multifactorial, with multiple parameters fluctuating over time. To better understand how cells respond to dynamically interacting factors, we quantified the effects of dual fluctuations of osmotic stress and glucose deprivation on yeast cells using microfluidics and time-lapse microscopy. Strikingly, we observed that cell proliferation, survival, and signaling depend on the phasing of the two periodic stresses. Cells divided faster, survived longer, and showed decreased transcriptional response when fluctuations of hyperosmotic stress and glucose deprivation occurred in phase than when the two stresses occurred alternatively. Therefore, glucose availability regulates yeast responses to dynamic osmotic stress, showcasing the key role of metabolic fluctuations in cellular responses to dynamic stress. We also found that mutants with impaired osmotic stress response were better adapted to alternating stresses than wild-type cells, showing that genetic mechanisms of adaptation to a persistent stress factor can be detrimental under dynamically interacting conditions.


Assuntos
Osmorregulação , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Pressão Osmótica , Proliferação de Células , Glucose
12.
J Phys Chem B ; 128(16): 3904-3909, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38613503

RESUMO

Recently, zwitterions have been proposed as novel cryoprotectants. However, some cells are difficult to cryopreserve using aqueous zwitterion solutions alone. We investigated here the reason for cell damage in such cells, and it was the osmotic pressure after freeze concentration. Furthermore, the addition of dimethyl sulfoxide (DMSO) has been reported to improve the cryoprotective effect in such cells: the zwitterion/DMSO aqueous solution shows a higher cryoprotective effect than the commercial cryoprotectant. This study also clarified the mechanisms underlying the improvement in a cryoprotective effect. The addition of cell-permeable DMSO alleviated the osmotic pressure after the freeze concentration. This alleviation was also found to be a key factor for cryopreserving cell spheroids, while there has been no insight into this phenomenon.


Assuntos
Criopreservação , Crioprotetores , Dimetil Sulfóxido , Pressão Osmótica , Dimetil Sulfóxido/química , Dimetil Sulfóxido/farmacologia , Crioprotetores/química , Crioprotetores/farmacologia , Pressão Osmótica/efeitos dos fármacos , Humanos , Soluções , Sobrevivência Celular/efeitos dos fármacos
13.
Cells ; 13(7)2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38607028

RESUMO

Absorption spectra of red blood cell (RBC) suspensions are investigated in an osmolarity range in the medium from 200 mOsm to 900 mOsm. Three spectral parameters are used to characterize the process of swelling or shrinkage of RBC-the absorbance at 700 nm, the Soret peak height relative to the spectrum background, and the Soret peak wavelength. We show that with an increase in the osmolarity, the absorbance at 700 nm increases and the Soret peak relative height decreases. These changes are related to the changes in the RBC volume and the resulting increase in the hemoglobin intracellular concentration and index of refraction. Confocal microscopy and flow cytometry measurements supported these conclusions. The maximum wavelength of the Soret peak increases with increasing osmolarity due to changes in the oxygenation state of hemoglobin. Using these spectrum parameters, the process of osmosis in RBCs can be followed in real time, but it can also be applied to various processes, leading to changes in the volume and shape of RBCs. Therefore, we conclude that UV-Vis absorption spectrophotometry offers a convenient, easily accessible, and cost-effective method to monitor changes in RBC, which can find applications in the field of drug discovery and diagnostics of RBC and hemoglobin disorders.


Assuntos
Eritrócitos , Hemoglobinas , Pressão Osmótica , Espectrofotometria , Concentração Osmolar
14.
J Physiol ; 602(8): 1623-1636, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38598430

RESUMO

Two-pore channels and TRP mucolipins are ubiquitous endo-lysosomal cation channels of pathophysiological relevance. Both are Ca2+-permeable and regulated by phosphoinositides, principally PI(3,5)P2. Accumulating evidence has uncovered synergistic channel activation by PI(3,5)P2 and endogenous metabolites such as the Ca2+ mobilizing messenger NAADP, synthetic agonists including approved drugs and physical cues such as voltage and osmotic pressure. Here, we provide an overview of this coordination.


Assuntos
Canais de Cálcio , Canais de Potencial de Receptor Transitório , Canais de Cálcio/metabolismo , Canais de Dois Poros , Cálcio/metabolismo , Lisossomos/metabolismo , NADP/metabolismo , Pressão Osmótica , Canais de Potencial de Receptor Transitório/metabolismo
15.
Biochem Biophys Res Commun ; 714: 149956, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38663095

RESUMO

BACKGROUND: Maize is a major cereal crop world widely, however, the yield of maize is frequently limited by dehydration and even death of plants, which resulted from osmotic stress such as drought and salinity. Dissection of molecular mechanisms controlling stress tolerance will enable plant scientists and breeders to increase crops yield by manipulating key regulatory components. METHODS: The candidate OSR1 gene was identified by map-based cloning. The expression level of OSR1 was verified by qRT-PCR and digital PCR in WT and osr1 mutant. Electrophoretic mobility shift assay, transactivation activity assay, subcellular localization, transcriptome analysis and physiological characters measurements were conducted to analyze the function of OSR1 in osmotic stress resistance in maize. RESULTS: The osr1 mutant was significantly less sensitive to osmotic stress than the WT plants and displayed stronger water-holding capacity, and the OSR1 homologous mutant in Arabidopsis showed a phenotype similar with maize osr1 mutant. Differentially expressed genes (DEGs) were identified between WT and osr1 under osmotic stress by transcriptome analysis, the expression levels of many genes, such as LEA, auxin-related factors, PPR family members, and TPR family members, changed notably, which may primarily involve in osmotic stress or promote root development. CONCLUSIONS: OSR1 may serve as a negative regulatory factor in response to osmotic stress in maize. The present study sheds new light on the molecular mechanisms of osmotic stress in maize.


Assuntos
Regulação da Expressão Gênica de Plantas , Pressão Osmótica , Proteínas de Plantas , Fatores de Transcrição , Zea mays , Zea mays/genética , Zea mays/metabolismo , Zea mays/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Mutação , Estresse Fisiológico/genética , Perfilação da Expressão Gênica
16.
Bioresour Technol ; 400: 130648, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38561153

RESUMO

Open unsterile fermentation of the low-cost non-food crop, sweet sorghum, is an economically feasible lactic acid biosynthesis process. However, hyperosmotic stress inhibits microbial metabolism and lactic acid biosynthesis, and engineering strains with high osmotic tolerance is challenging. Herein, heavy ion mutagenesis combined with osmotic pressure enrichment was used to engineer a hyperosmotic-tolerant Bacillus coagulans for L-lactic acid production. The engineered strain had higher osmotic pressure tolerance, when compared with the parental strain, primarily owing to its improved properties such as cell viability, cellular antioxidant capacity, and NADH supply. In a pilot-scale open unsterile fermentation using sweet sorghum juice as a feedstock, the engineered strain produced 94 g/L L-lactic acid with a yield of 91 % and productivity of 6.7 g/L/h, and optical purity of L-lactic acid at the end of fermentation was 99.8 %. In short, this study provided effective and low-cost approach to produce polymer-grade L-lactic acid.


Assuntos
Bacillus coagulans , Fermentação , Ácido Láctico , Pressão Osmótica , Sorghum , Ácido Láctico/biossíntese , Ácido Láctico/metabolismo , Sorghum/metabolismo
17.
Am J Sports Med ; 52(6): 1596-1607, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38581200

RESUMO

BACKGROUND: Physiological 0.9% saline is commonly used as an irrigation fluid in modern arthroscopy. There is a growing body of evidence that a hyperosmolar saline solution has chondroprotective effects, especially if iatrogenic injury occurs. PURPOSE: To (1) corroborate the superiority of a hyperosmolar saline solution regarding chondrocyte survival after mechanical injury and (2) observe the modulatory response of articular cartilage to osmotic stress and injury. STUDY DESIGN: Controlled laboratory study. METHODS: Osteochondral explants were isolated from bovine stifle joints and exposed to either 0.9% saline (308 mOsm) or hyperosmolar saline (600 mOsm) and then damaged with a sharp dermatome blade to attain a confined full-thickness cartilage injury site, incubated in the same fluids for another 3 hours, and transferred to chondropermissive medium for further culture for 1 week. Chondrocyte survival was assessed by confocal imaging, while the cellular response was evaluated over 1 week by relative gene expression for apoptotic and inflammatory markers and mediator release into the medium. RESULTS: The full-thickness cartilage cut resulted in a confined zone of cell death that mainly affected superficial zone chondrocytes. Injured samples that were exposed to hyperosmolar saline showed less expansion of cell death in both the axial (P < .007) and the coronal (P < .004) plane. There was no progression of cell death during the following week of culture. Histological assessment revealed an intact cartilage matrix and normal chondrocyte morphology. Inflammatory and proapoptotic genes were upregulated on the first days postexposure with a notable downregulation toward day 7. Mediator release into the medium was concentrated on day 3. CONCLUSION: This in vitro cartilage injury model provides further evidence for the chondroprotective effect of a hyperosmolar saline irrigation fluid, as well as novel data on the capability of articular cartilage to quickly regain joint homeostasis after osmotic stress and injury. CLINICAL RELEVANCE: Raising the osmolarity of an irrigating solution may be a simple and safe strategy to protect articular cartilage during arthroscopic surgery.


Assuntos
Cartilagem Articular , Condrócitos , Animais , Cartilagem Articular/efeitos dos fármacos , Cartilagem Articular/lesões , Bovinos , Condrócitos/efeitos dos fármacos , Pressão Osmótica , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Irrigação Terapêutica , Solução Salina
18.
Gene ; 913: 148371, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38485034

RESUMO

The intestinal microbiota is increasingly recognized as playing an important role in aquatic animals. To investigate the functional roles and mechanisms of the intestinal microbial genes/enzymes responding to salinity stress or osmotic pressure in fish, metagenomic analysis was carried out to evaluate the response of intestinal microbiota and especially their functional genes/enzymes from freshwater (the control group) to acute high salinity stress (the treatment group) in Nile tilapia. Our results showed that at the microbial community level, the intestinal microbiota in Nile tilapia generally underwent significant changes in diversity after acute high salinity stress. Among them, the shift in the bacterial community (mainly from Actinobacteria to Proteobacteria) dominated and had a large impact, the fungal community showed a very limited response, and other microbiota, such as phages, likely had a negligible response. At the functional level, the intestinal bacteriadecreased the normal physiological demand and processes, such as those of the digestive system and nervous system, but enhanced energy metabolism. Furthermore, at the gene level, some gene biomarkers, such as glutathione S-transferase, myo-inositol-1(or 4)-monophosphatase, glycine betaine/proline transport system permease protein, and some families of carbohydrate-active enzymes (GT4, GT2), were significantly enriched. However, GH15, GH23 and so on were significantly reduced. Exploring the functional details of the intestinal microbial genes/enzymes that respond to salinity stress in Nile tilapia sheds light on the mechanism of action of the intestinal microbiota with respect to the salinity adaptation of fish.


Assuntos
Ciclídeos , Animais , Ciclídeos/genética , Salinidade , Intestinos , Pressão Osmótica , Estresse Salino
19.
Mol Plant Pathol ; 25(3): e13436, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38460112

RESUMO

While the response of Arabidopsis thaliana to drought, herbivory or fungal infection has been well-examined, the consequences of exposure to a series of such (a)biotic stresses are not well studied. This work reports on the genetic mechanisms underlying the Arabidopsis response to single osmotic stress, and to combinatorial stress, either fungal infection using Botrytis cinerea or herbivory using Pieris rapae caterpillars followed by an osmotic stress treatment. Several small-effect genetic loci associated with rosette dry weight (DW), rosette water content (WC), and the projected rosette leaf area in response to combinatorial stress were mapped using univariate and multi-environment genome-wide association approaches. A single-nucleotide polymorphism (SNP) associated with DROUGHT-INDUCED 19 (DI19) was identified by both approaches, supporting its potential involvement in the response to combinatorial stress. Several SNPs were found to be in linkage disequilibrium with known stress-responsive genes such as PEROXIDASE 34 (PRX34), BASIC LEUCINE ZIPPER 25 (bZIP25), RESISTANCE METHYLATED GENE 1 (RMG1) and WHITE RUST RESISTANCE 4 (WRR4). An antagonistic effect between biotic and osmotic stress was found for prx34 and arf4 mutants, which suggests PRX34 and ARF4 play an important role in the response to the combinatorial stress.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Micoses , Estudo de Associação Genômica Ampla , Arabidopsis/microbiologia , Pressão Osmótica , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Proteínas de Arabidopsis/genética
20.
PeerJ ; 12: e16994, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38426134

RESUMO

Background: Monitoring cellular processes across different levels of complexity, from the cellular to the tissue scale, is important for understanding tissue structure and function. However, it is challenging to monitor and estimate these structural and dynamic interactions within three-dimensional (3D) tissue models. Objective: The aim of this study was to design a method for imaging, tracking, and quantifying 3D changes in cell morphology (shape and size) within liver tissue, specifically a precision-cut liver slice (PCLS). A PCLS is a 3D model of the liver that allows the study of the structure and function of liver cells in their native microenvironment. Methods: Here, we present a method for imaging liver tissue during anisosmotic exposure in a multispectral four-dimensional manner. Three metrics of tissue morphology were measured to quantify the effects of osmotic stress on liver tissue. We estimated the changes in the volume of whole precision cut liver slices, quantified the changes in nuclei position, and calculated the changes in volumetric responses of tissue-embedded cells. Results: During equilibration with cell-membrane-permeating and non-permeating solutes, the whole tissue experiences shrinkage and expansion. As nuclei showed a change in position and directional displacement under osmotic stress, we demonstrate that nuclei could be used as a probe to measure local osmotic and mechanical stress. Moreover, we demonstrate that cells change their volume within tissue slices as a result of osmotic perturbation and that this change in volume is dependent on the position of the cell within the tissue and the duration of the exposure. Conclusion: The results of this study have implications for a better understanding of multiscale transport, mechanobiology, and triggered biological responses within complex biological structures.


Assuntos
Fígado , Ratos , Animais , Ratos Wistar , Imagem com Lapso de Tempo , Fígado/diagnóstico por imagem , Osmose , Pressão Osmótica
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