scholarly journals Exopolysaccharide II Is Relevant for the Survival of Sinorhizobium meliloti under Water Deficiency and Salinity Stress

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4876
Author(s):  
Emiliano Primo ◽  
Pablo Bogino ◽  
Sacha Cossovich ◽  
Emiliano Foresto ◽  
Fiorela Nievas ◽  
...  
Keyword(s):  
Sinorhizobium Meliloti ◽  
Protective Role ◽  
Environmental Stressors ◽  
Saline Stress ◽  
Symbiotic Association ◽  
Atmospheric Nitrogen ◽  
Water Deficiency ◽  
Wild Type ◽  
Induced Stress

Sinorhizobium meliloti is a soil bacterium of great agricultural importance because of its ability to fix atmospheric nitrogen in symbiotic association with alfalfa (Medicago sativa) roots. We looked into the involvement of exopolysaccharides (EPS) in its survival when exposed to different environmental stressors, as well as in bacteria–bacteria and bacteria–substrate interactions. The strains used were wild-type Rm8530 and two strains that are defective in the biosynthesis of EPS II: wild-type Rm1021, which has a non-functional expR locus, and mutant Rm8530 expA. Under stress by water deficiency, Rm8530 remained viable and increased in number, whereas Rm1021 and Rm8530 expA did not. These differences could be due to Rm8530′s ability to produce EPS II. Survival experiments under saline stress showed that viability was reduced for Rm1021 but not for Rm8530 or Rm8530 expA, which suggests the existence of some regulating mechanism dependent on a functional expR that is absent in Rm1021. The results of salinity-induced stress assays regarding biofilm-forming capacity (BFC) and autoaggregation indicated the protective role of EPS II. As a whole, our observations demonstrate that EPS play major roles in rhizobacterial survival.

scholarly journals Protective role of foliar-applied nitric oxide in Triticum aestivum under saline stress

2013 ◽  
Vol 37 ◽  
pp. 1155-1165 ◽  
Author(s):  
Farhana KAUSAR ◽  
Muhammad SHAHBAZ ◽  
Muhammad ASHRAF
Keyword(s):  
Nitric Oxide ◽  
Triticum Aestivum ◽  
Protective Role ◽  
Saline Stress

scholarly journals Susceptibility to Entamoeba histolytica intestinal infection is related to reduction in natural killer T-lymphocytes in C57BL/6 mice

2012 ◽  
Vol 4 (1) ◽  
pp. 27 ◽  
Author(s):  
Fabrício M.S. Oliveira ◽  
Bernardo C. Horta ◽  
Luana O. Prata ◽  
Andrezza F. Santiago ◽  
Andréa C. Alves ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Natural Killer ◽  
Entamoeba Histolytica ◽  
Protective Role ◽  
Amoebic Liver Abscess ◽  
Wild Type ◽  
Quantitative Analyses ◽  
Cd1 Mice ◽  
Natural Killer T

<em>Entamoeba histolytica</em> is a protozoan that causes amoebiasis. Recent studies demonstrated that natural killer T lymphocytes (NKT) are critical for preventing the development of amoebic liver abscess. In spite of that, there are only a handful of studies in the area. Herein, we explored the role of NKT cells in <em>E. histolytica </em>infection using C57BL/6 wild-type and CD1-/- mice. Animals were inoculated with <em>E. histolytica</em> and sacrificed 48 hours later to collect caecum samples that were used for quantitative analyses of lesions, trophozoites, NK1.1+ T lymphocytes and expression of the mucus protein MUC-2 by immunohistochemistry technique. Quantitative analyses confirmed that the frequency of NK1.1+ T cells was significantly lower in samples from C57BL/6 CD1-/- mice as compared to their wild type (WT) counterparts. The extension of necrotic mucosa was larger and the number of trophozoites higher in Entamoeba (Eh)-infected CD1-/- mice when compared with Eh-infected WT mice. In mice from both groups, noninfected (CTRL) and Eh-infected CD1-/-, there was a reduction in the thickness of the caecal mucosa and in the MUC-2-stained area in comparison with CTRL- and Eh-WT mice. Our results showed that NKT lymphocytes contribute to resistance against <em>Entamoeba histolytica</em> infection and to the control of inflammation in the colitis induced by infection. The presence of a normal epithelial layer containing appropriate levels of mucus had also a protective role against infection.

scholarly journals MtBZR1 Plays an Important Role in Nodule Development in Medicago truncatula

2019 ◽  
Vol 20 (12) ◽  
pp. 2941
Author(s):  
Can Cui ◽  
Hongfeng Wang ◽  
Limei Hong ◽  
Yiteng Xu ◽  
Yang Zhao ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Normal Growth ◽  
Dry Mass ◽  
Growth Conditions ◽  
Nodule Development ◽  
Functional Study ◽  
Loss Of Function ◽  
Wild Type

Brassinosteroid (BR) is an essential hormone in plant growth and development. The BR signaling pathway was extensively studied, in which BRASSINAZOLE RESISTANT 1 (BZR1) functions as a key regulator. Here, we carried out a functional study of the homolog of BZR1 in Medicago truncatula R108, whose expression was induced in nodules upon Sinorhizobium meliloti 1021 inoculation. We identified a loss-of-function mutant mtbzr1-1 and generated 35S:MtBZR1 transgenic lines for further analysis at the genetic level. Both the mutant and the overexpression lines of MtBZR1 showed no obvious phenotypic changes under normal growth conditions. After S. meliloti 1021 inoculation, however, the shoot and root dry mass was reduced in mtbzr1-1 compared with the wild type, caused by partially impaired nodule development. The transcriptomic analysis identified 1319 differentially expressed genes in mtbzr1-1 compared with wild type, many of which are involved in nodule development and secondary metabolite biosynthesis. Our results demonstrate the role of MtBZR1 in nodule development in M. truncatula, shedding light on the potential role of BR in legume–rhizobium symbiosis.

scholarly journals The RcsCB His-Asp Phosphorelay System Is Essential To Overcome Chlorpromazine-Induced Stress in Escherichia coli

2002 ◽  
Vol 184 (10) ◽  
pp. 2850-2853 ◽  
Author(s):  
Annie Conter ◽  
Rachel Sturny ◽  
Claude Gutierrez ◽  
Kaymeuang Cam
Keyword(s):  
Escherichia Coli ◽  
Type Strain ◽  
Wild Type Strain ◽  
Cell Envelope ◽  
Wild Type ◽  
E Coli ◽  
Induced Stress ◽  
Mutant Strains ◽  
Molecular Nature

ABSTRACT The RcsCB His-Asp phosphorelay system regulates the expression of several genes of Escherichia coli, but the molecular nature of the inducing signal is still unknown. We show here that treatment of an exponentially growing culture of E. coli with the cationic amphipathic compound chlorpromazine (CPZ) stimulates expression of a set of genes positively regulated by the RcsCB system. This induction is abolished in rcsB or rcsC mutant strains. In addition, treatment with CPZ inhibits growth. The wild-type strain is able to recover from this inhibition and resume growth after a period of adaptation. In contrast, strains deficient in the RcsCB His-Asp phosphorelay system are hypersensitive to CPZ. These results suggest that cells must express specific RcsCB-regulated genes in order to cope with the CPZ-induced stress. This is the first report of the essential role of the RcsCB system in a stress situation. These results also strengthen the notion that alterations of the cell envelope induce a signal recognized by the RcsC sensor.

scholarly journals An Orphan LuxR Homolog of Sinorhizobium meliloti Affects Stress Adaptation and Competition for Nodulation

2008 ◽  
Vol 75 (4) ◽  
pp. 946-955 ◽  
Author(s):  
Arati V. Patankar ◽  
Juan E. Gonz�lez
Keyword(s):  
Sinorhizobium Meliloti ◽  
Wild Type Strain ◽  
Symbiotic Association ◽  
Response Regulators ◽  
Sensing System ◽  
Luxr Homolog ◽  
Active Methyl ◽  
Quorum Sensing System ◽  
Type Response

ABSTRACT The Sin/ExpR quorum-sensing system of Sinorhizobium meliloti plays an important role in the symbiotic association with its host plant, Medicago sativa. The LuxR-type response regulators of the Sin system include the synthase (SinI)-associated SinR and the orphan regulator ExpR. Interestingly, the S. meliloti Rm1021 genome codes for four additional putative orphan LuxR homologs whose regulatory roles remain to be identified. These response regulators contain the characteristic domains of the LuxR family of proteins, which include an N-terminal autoinducer/response regulatory domain and a C-terminal helix-turn-helix domain. This study elucidates the regulatory role of one of the orphan LuxR-type response regulators, NesR. Through expression and phenotypic analyses, nesR was determined to affect the active methyl cycle of S. meliloti. Moreover, nesR was shown to influence nutritional and stress response activities in S. meliloti. Finally, the nesR mutant was deficient in competing with the wild-type strain for plant nodulation. Taken together, these results suggest that NesR potentially contributes to the adaptability of S. meliloti when it encounters challenges such as high osmolarity, nutrient starvation, and/or competition for nodulation, thus increasing its chances for survival in the stressful rhizosphere.

scholarly journals Hepatic progenitor cells promote the repair of schistosomiasis liver injury by inhibiting IL-33 secretion in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Beibei Zhang ◽  
Xiaoying Wu ◽  
Jing Li ◽  
An Ning ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Liver Injury ◽  
Progenitor Cells ◽  
Normal Liver ◽  
Protective Role ◽  
Dependent Manner ◽  
Hepatic Progenitor Cells ◽  
Wild Type ◽  
Mice Model

Abstract Background Hepatic schistosomiasis, a chronic liver injury induced by long-term Schistosoma japonicum (S. japonicum) infection, is characterized by egg granulomas and fibrotic pathology. Hepatic progenitor cells (HPCs), which are nearly absent or quiescent in normal liver, play vital roles in chronic and severe liver injury. But their role in the progression of liver injury during infection remains unknown. Methods In this study, the hepatic egg granulomas, fibrosis and proliferation of HPCs were analyzed in the mice model of S. japonicum infection at different infectious stages. For validating the role of HPCs in hepatic injury, tumor necrosis factor-like-weak inducer of apoptosis (TWEAK) and TWEAK blocking antibody were used to manipulate the proliferation of HPCs in wild-type and IL-33−/− mice infected with S. japonicum. Results We found that the proliferation of HPCs was accompanied by inflammatory granulomas and fibrosis formation. HPCs expansion promoted liver regeneration and inhibited inflammatory egg granulomas, as well as the deposition of fibrotic collagen. Interestingly, the expression of IL-33 was negatively associated with HPCs’ expansion. There were no obvious differences of liver injury caused by infection between wild-type and IL-33−/− mice with HPCs’ expansion. However, liver injury was more attenuated in IL-33−/− mice than wild-type mice when the proliferation of HPCs was inhibited by anti-TWEAK. Conclusions Our data uncovered a protective role of HPCs in hepatic schistosomiasis in an IL-33-dependent manner, which might provide a promising progenitor cell therapy for hepatic schistosomiasis.

scholarly journals The Protective Role of 28-Homobrassinolide and Glomus versiforme in Cucumber to Withstand Saline Stress

Plants ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 42 ◽  
Author(s):  
Husain Ahmad ◽  
Sikandar Hayat ◽  
Muhammad Ali ◽  
Hongjiu Liu ◽  
Xuejin Chen ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Agricultural Practices ◽  
Arbuscular Mycorrhizal ◽  
Sodium Concentration ◽  
Protective Role ◽  
Saline Stress ◽  
Glomus Versiforme ◽  
Crop Tolerance ◽  
Strategic Role

The strategic role of phytohormones and arbuscular mycorrhizal fungi (AMF) to overcome various stress conditions is gaining popularity in sustainable agricultural practices. This current study aims to investigate and identify the protective roles of 28-homobrassinolide (HBL) and Glomus versiforme on two cucumber cultivars (salt sensitive Jinyou 1# and tolerant Chanchun mici (CCMC)) grown under saline conditions (100 mM NaCl). HBL and AMF were applied as individual and combined treatments on two cucumber cultivars and their effects were observed on the morphological growth and physiology under control and saline conditions. Findings revealed that the treated plants showed better performance under saline conditions through improved photosynthesis, leaf relative water content, and decreased electrolyte leakage in tolerant cultivar (CCMC) and to a lesser extent in sensitive (Jinyou 1#) cultivar. Comparable differences were noticed in the antioxidant enzymes activity such as superoxide dismutase, catalase, and peroxidase after every 10 days in both cultivars. Treating the plants with HBL and AMF also improved the mineral uptake regulation and lowered sodium concentration in roots compared to that in the non-treated plants. Current findings suggest that the protective role of HBL and AMF involves the regulation of antioxidants and lowers the risk of ion toxicity in the cucumber and hence enhance tolerance to salinity. These results are promising, but further studies are needed to verify the crop tolerance to stress and help in sustainable agricultural production, particularly vegetables that are prone to salinity.

FGF21 prevents low protein diet-induced renal inflammation in aged mice

2021 ◽  
Author(s):  
Han Fang ◽  
Sujoy Ghosh ◽  
Landon Sims ◽  
Kirsten P. Stone ◽  
Cristal M Hill ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Renal Damage ◽  
Protective Role ◽  
Wild Type ◽  
Kidney Weight ◽  
Albumin Creatinine Ratio ◽  
Low Protein ◽  
The Impact ◽  
Protein Diets

Low protein diets extend lifespan through a comprehensive improvement in metabolic health across multiple tissues and organs. Many of these metabolic responses to protein restriction are secondary to transcriptional activation and release of FGF21 from the liver. However, the effects of a low protein (LP) diet on the kidney in the context of aging has not been examined. Therefore, the goal of the current study was to investigate the impact of chronic consumption of a LP diet on the kidney in aging mice lacking FGF21. Wild type (WT, C57BL/6J) and FGF21 KO mice were fed a normal protein (NP, 20% casein) or a LP (5% casein) diet ad libitum from 3 to19 months of age. The LP diet led to a decrease in kidney weight and urinary albumin/creatinine ratio in both WT and FGF21 KO mice. Although the LP diet produced only mild fibrosis and infiltration of leukocytes in WT kidneys, the effects were significantly exacerbated by the absence of FGF21. Accordingly, transcriptomic analysis showed that inflammation-related pathways were significantly enriched and upregulated in response to LP diet in FGF21 KO but not WT mice. Collectively, these data demonstrate that the LP diet negatively affected the kidney during aging, but in the absence of FGF21, the LP diet-induced renal damage and inflammation were significantly worse, indicating a protective role of FGF21 in the kidney.

scholarly journals Stress-induced Cdk5 activity enhances cytoprotective basal autophagy in Drosophila melanogaster by phosphorylating acinus at serine437

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Nilay Nandi ◽  
Lauren K Tyra ◽  
Drew Stenesen ◽  
Helmut Krämer
Keyword(s):  
Drosophila Melanogaster ◽  
Nuclear Protein ◽  
Protective Role ◽  
Alpha Synuclein ◽  
Wild Type ◽  
Gain Of Function ◽  
Mitotic Kinase

Cdk5 is a post-mitotic kinase with complex roles in maintaining neuronal health. The various mechanisms by which Cdk5 inhibits and promotes neurodegeneration are still poorly understood. Here, we show that in Drosophila melanogaster Cdk5 regulates basal autophagy, a key mechanism suppressing neurodegeneration. In a targeted screen, Cdk5 genetically interacted with Acinus (Acn), a primarily nuclear protein, which promotes starvation-independent, basal autophagy. Loss of Cdk5, or its required cofactor p35, reduces S437-Acn phosphorylation, whereas Cdk5 gain-of-function increases pS437-Acn levels. The phospho-mimetic S437D mutation stabilizes Acn and promotes basal autophagy. In p35 mutants, basal autophagy and lifespan are reduced, but restored to near wild-type levels in the presence of stabilized AcnS437D. Expression of aggregation-prone polyQ-containing proteins or the Amyloid-β42 peptide, but not alpha-Synuclein, enhances Cdk5-dependent phosphorylation of S437-Acn. Our data indicate that Cdk5 is required to maintain the protective role of basal autophagy in the initial responses to a subset of neurodegenerative challenges.

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