scholarly journals Proteomic Analyses To Reveal the Protective Role of Glutathione in Resistance of Lactococcus lactis to Osmotic Stress

2010 ◽  
Vol 76 (10) ◽  
pp. 3177-3186 ◽  
Author(s):  
Yanhe Zhang ◽  
Yanping Zhang ◽  
Yan Zhu ◽  
Shaoming Mao ◽  
Yin Li
Keyword(s):  
Osmotic Stress ◽  
Lactococcus Lactis ◽  
Acid Stress ◽  
Sugar Metabolism ◽  
Protective Role ◽  
Starter Cultures ◽  
Transmission Electron ◽  
Proteomic Analyses ◽  
Dairy Starter Cultures

ABSTRACT Previously, we have shown that glutathione can protect Lactococcus lactis against oxidative stress and acid stress. In this study, we show that glutathione taken up by L. lactis SK11 can protect this organism against osmotic stress. When exposed to 5 M NaCl, L. lactis SK11 cells containing glutathione exhibited significantly improved survival compared to the control cells. Transmission electron microscopy showed that the integrity of L. lactis SK11 cells containing glutathione was maintained for at least 24 h, whereas autolysis of the control cells occurred within 2 h after exposure to this osmotic stress. Comparative proteomic analyses using SK11 cells containing or not containing glutathione that were exposed or not exposed to osmotic stress were performed. The results revealed that 21 of 29 differentially expressed proteins are involved in metabolic pathways, mainly sugar metabolism. Several glycolytic enzymes of L. lactis were significantly upregulated in the presence of glutathione, which might be the key for improving the general stress resistance of a strain. Together with the results of previous studies, the results of this study demonstrated that glutathione plays important roles in protecting L. lactis against multiple environmental stresses; thus, glutathione can be considered a general protectant for improving the robustness and stability of dairy starter cultures.

scholarly journals Hydrogen sulfide and potassium synergistically induce osmotic stress tolerance through regulation of H+-ATPase activity and sugar metabolism in tomato seedlings

2021 ◽  
Author(s):  
Manzer H. Siddiqui ◽  
Soumya Mukherjee ◽  
Saud Alamri ◽  
Yanbo Hu ◽  
Abdullah Alamri ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Osmotic Stress ◽  
Atpase Activity ◽  
Channel Blocker ◽  
Sugar Metabolism ◽  
Decisive Role ◽  
K Channel ◽  
Tomato Seedlings ◽  
Osmotic Stress Tolerance

Abstract Potassium (K) is an essential macronutrient which is known to regulate key metabolic processes, modulate enzyme activity and plays a decisive role in osmotic adjustment in plants. Present work evaluates the role of K in the regulation of endogenous hydrogen sulfide (H2S) signaling in modulating the tolerance of tomato (Solanum lycopersicum L. Mill.) seedlings to osmotic stress. The findings reveal that exposure of seedlings to 15% (w/v) polyethylene glycol 8000 (PEG) led to a substantial decrease in leaf K content which was associated with reduced H+-ATPase activity. Exogenous application of K to the stressed seedlings significantly improved endogenous K content. Treatment with sodium orthovanadate (SOV, PM H+-ATPase inhibitor) and tetraethylammonium chloride (TEA, K channel blocker) suggests that exogenous K stimulated H+-ATPase activity that further regulated endogenous K content in tomato seedlings subjected to osmotic stress. Moreover, reduction in H+-ATPase activity by hypotaurine (H2S scavenger) substantiates the role of endogenous H2S in the regulation of H+-ATPase activity. Elevation in endogenous K content enhanced the biosynthesis of hydrogen sulfide (H2S) through enhancing the synthesis of cysteine, the H2S precursor. Synergistic action of H2S and K effectively neutralized osmotic stress by regulating sugar metabolism that resulted in osmotic adjustment, as witnessed by reduced water loss and improved hydration level of the stressed seedlings. Cross talk of H2S and K also assisted the seedlings in the activation of antioxidant enzymes that controlled the generation of reactive oxygen species and led to the protection against oxidative stress. The integrative role of H2S and K signaling was validated using hypotaurine (H2S scavenger) and TEA (K channel blocker) which weakened the protection against osmotic stress induced impairments. In conclusion, exogenous K and endogenous H2S regulate H+-ATPase activity which plays a decisive role in the maintenance of endogenous K homeostasis. Thus, present work reveals that K and H2S crosstalk is essential for modulation of osmotic stress tolerance in tomato seedlings.

scholarly journals Protective Effects of Anti-depressant Citalopram Against Abnormal APP Processing and Amyloid Beta-induced Mitochondrial Dynamics, Biogenesis, Mitophagy and Synaptic Toxicities in Alzheimer’s Disease

2021 ◽  
Author(s):  
Arubala P Reddy ◽  
Xiangling Yin ◽  
Neha Sawant ◽  
P Hemachandra Reddy
Keyword(s):  
Electron Microscopy ◽  
Alzheimer’S Disease ◽  
Transmission Electron Microscopy ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Fission ◽  
Protective Role ◽  
Mrna Levels ◽  
Ht22 Cells ◽  
Transmission Electron

Abstract The purpose of this study is to study the neuroprotective role of selective serotonin reuptake inhibitor (SSRI), citalopram against Alzheimer’s disease (ad). Multiple SSRIs, including citalopram are reported to treat patients with depression, anxiety, and ad. However, their protective cellular mechanisms have not been studied completely. In the current study, we investigated the protective role of citalopram against impaired mitochondrial dynamics, defective mitochondrial biogenesis, defective mitophagy, and synaptic dysfunction in immortalized mouse primary hippocampal cells (HT22) expressing mutant APP (SWI/IND) mutations. Using quantitative RT-PCR, immunoblotting, biochemical methods and transmission electron microscopy methods, we assessed mutant full-length APP/C-terminal fragments and Aβ levels and mRNA and protein levels of mitochondrial dynamics, biogenesis, mitophagy, and synaptic genes in mAPP-HT22 cells and mAPP-HT22 cells treated with citalopram. Increased levels of mRNA levels of mitochondrial fission genes, decreased levels of fusion biogenesis, autophagy, mitophagy and synaptic genes were found in mAPP-HT22 cells relative to WT-HT22 cells. However, in mAPP-HT22 cells treated with citalopram compared to mAPP-HT22 cells, revealed reduced levels of the mitochondrial fission genes, increased fusion, biogenesis, autophagy, mitophagy, and synaptic genes. Our protein data agrees with mRNA levels. Transmission electron microscopy revealed significantly increased mitochondrial numbers and reduced mitochondrial length in mAPP-HT22 cells; these were reversed in citalopram treated mAPP-HT22 cells. Cell survival rates were increased in citalopram treated mAPP-HT22 relative to citalopram-untreated mAPP-HT22. Further, mAPP and C-terminal fragments were also reduced in citalopram treated cells. These findings suggest that citalopram reduces mutant APP and Aβ and mitochondrial toxicities and may have a protective role of mutant APP and Aβ-induced injuries in patients with depression, anxiety, and ad.

scholarly journals Schistosoma mansoni egg-derived extracellular vesicles: A promising vaccine candidate against murine schistosomiasis

2021 ◽  
Vol 15 (10) ◽  
pp. e0009866
Author(s):  
Shereen F. Mossallam ◽  
Iman F. Abou-El-Naga ◽  
Amany Abdel Bary ◽  
Eman A. Elmorsy ◽  
Radwa G. Diab
Keyword(s):  
Schistosoma Mansoni ◽  
Extracellular Vesicles ◽  
Vaccine Candidate ◽  
Protective Efficacy ◽  
Protective Role ◽  
Immunological Parameters ◽  
Transmission Electron ◽  
Potential Vaccine ◽  
Protein Components

Extracellular vesicles (EVs) are protein-loaded nano-scaled particles that are extracellularly released by eukaryotes and prokaryotes. Parasite’s EVs manipulate the immune system, making them probable next-generation vaccines. Schistosomal EVs carry different proteins of promising immunizing potentials. For evaluating the immune-protective role of Schistosoma mansoni (S. mansoni) egg-derived EVs against murine schistosomiasis, EVs were isolated from cultured S. mansoni eggs by progressive sequential cooling ultra-centrifugation technique. Isolated EVs were structurally identified using transmission electron microscope and their protein was quantified by Lowry’s technique. Experimental mice were subcutaneously immunized with three doses of 20 μg EVs (with or without alum adjuvant); every two weeks, then were challenged with S. mansoni cercariae two weeks after the last immunizing dose. Six weeks post infection, mice were sacrificed for vaccine candidate assessment. EVs protective efficacy was evaluated through parasitological, histopathological, and immunological parameters. Results showed significant reduction of tegumentally deranged adult worms, hepatic and intestinal egg counts reduction by 46.58%, 93.14% and 93.17% respectively, accompanied by remarkable amelioration of sizes, numbers and histopathology of hepatic granulomata mediated by high interferon gamma (IFN γ) and antibody level. Using sera from vaccinated mice, the molecular weight of EVs’ protein components targeted by the antibody produced was recognized by western immunoblot. Results revealed two bands of ~ 14 KDa and ~ 21 KDa, proving that EVs are able to stimulate specific antibodies response. In conclusion, the present study highlighted the role of S. mansoni-egg derived EVs as a potential vaccine candidate against murine schistosomiasis mansoni.

scholarly journals Mucin-like molecules form a negatively charged coat that protects Trypanosoma cruzi trypomastigotes from killing by human anti-alpha-galactosyl antibodies

2000 ◽  
Vol 113 (7) ◽  
pp. 1299-1307 ◽  
Author(s):  
V.L. Pereira-Chioccola ◽  
A. Acosta-Serrano ◽  
I. Correia de Almeida ◽  
M.A. Ferguson ◽  
T. Souto-Padron ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Trypanosoma Cruzi ◽  
Surface Area ◽  
Protective Role ◽  
Ruthenium Red ◽  
Surface Coat ◽  
High Affinity ◽  
Transmission Electron ◽  
Major Surface

In the presence of sialic acid donors Trypanosoma cruzi acquires up to 10(7) sialic acid residues on its surface, in a reaction catalyzed by its unique trans-sialidase. Most of these sialic acid residues are incorporated into mucin-like glycoproteins. To further understand the biological role of parasite sialylation, we have measured the amount of mucin in this parasite. We found that both epimastigote and trypomastigote forms have the same number of mucin molecules per surface area, although trypomastigotes have less than 10% of the amount of glycoinositol phospholipids, the other major surface glycoconjugate of T. cruzi. Based on the estimated surface area of each mucin, we calculated that these molecules form a coat covering the entire trypomastigote cell. The presence of the surface coat is shown by transmission electron microscopy of Ruthenium Red-stained parasites. The coat was revealed by binding of antibodies isolated from Chagasic patients that react with high affinity to alpha-galactosyl epitopes present in the mucin molecule. When added to the trypomastigote, these antibodies cause an extensive structural perturbation of the parasite coat with formation of large blebs, ultimately leading to parasite lysis. Interestingly, lysis is decreased if the mucin coat is heavily sialylated. Furthermore, addition of MgCl2 reverses the protective effect of sialylation, suggesting that the sialic acid negative charges stabilize the surface coat. Inhibition of sialylation by anti-trans-sialidase antibodies, found in immunized animals, or human Chagasic sera, also increase killing by anti-alpha-galactosyl antibodies. Therefore, the large amounts of sialylated mucins, forming a surface coat on infective trypomastigote forms, have an important structural and protective role.

scholarly journals Protective Role of Ramipril and Candesartan against Myocardial Ischemic Reperfusion Injury: A Biochemical and Transmission Electron Microscopical Study

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Mohamed Saleem Thattakudian Sheik Uduman ◽  
Rajitha Bodd Reddy ◽  
Priyanka Punuru ◽  
Gopinath Chakka ◽  
Gauthaman Karunakaran
Keyword(s):  
Nitric Oxide ◽  
Reperfusion Injury ◽  
Protective Role ◽  
Global Ischemia ◽  
Protective Mechanism ◽  
Myocardial Tissue ◽  
Ischemic Reperfusion Injury ◽  
Ischemic Reperfusion ◽  
Transmission Electron

The present study was designed to investigate the role of combined administration of Ramipril and Candesartan againstin vitromyocardial ischemic reperfusion injury in rat. Male Wistar albino rats were divided into five groups (n=6) and treated with saline (10 mL/kg), Ramipril (2 mg/kg), Candesartan (1 mg/kg), and the combination of both drugs, respectively 24 h before induction of global ischemia (5 min of stabilization, 9 min of global ischemia, and 12 min of reflow). Combination of Ramipril and Candesartan when compared to the monotherapy significantly increased the levels of superoxide dismutase, reduced glutathione, catalase, and nitric oxide and decreased the levels of thiobarbituric acid reactive substances. In addition, the superior protective role of combination of Ramipril and Candesartan on ischemia induced myocardial damage was further confirmed by well preserved myocardial tissue architecture in light microscopy and transmission electron microscopy analysis studies. The combination was proved to be effective in salvaging the myocardial tissue against ischemic reperfusion injury when compared to the monotherapy of individual drugs and further investigations on protective mechanism of drugs by increasing the nitric oxide level at molecular levels are needed.

scholarly journals Lactococcus lactisDiversity in Undefined Mixed Dairy Starter Cultures as Revealed by Comparative Genome Analyses and Targeted Amplicon Sequencing ofepsD

2017 ◽  
Vol 84 (3) ◽  
Author(s):  
Cyril A. Frantzen ◽  
Hans Petter Kleppen ◽  
Helge Holo
Keyword(s):  
Lactococcus Lactis ◽  
Starter Culture ◽  
Amplicon Sequencing ◽  
Core Gene ◽  
Starter Cultures ◽  
Content Type ◽  
Genome Analyses ◽  
Dairy Starter Cultures ◽  
Rotation Strategy ◽  
Cheese Production

ABSTRACTUndefined mesophilic mixed (DL) starter cultures are used in the production of continental cheeses and contain unknown strain mixtures ofLactococcus lactisand leuconostocs. The choice of starter culture affects the taste, aroma, and quality of the final product. To gain insight into the diversity ofLactococcus lactisstrains in starter cultures, we whole-genome sequenced 95 isolates from three different starter cultures. Pan-genomic analyses, which included 30 publically available complete genomes, grouped the strains into 21L. lactissubsp. lactisand 28L. lactissubsp.cremorislineages. Only one of the 95 isolates grouped with previously sequenced strains, and the three starter cultures showed no overlap in lineage distributions. The culture diversity was assessed by targeted amplicon sequencing usingpurR, a core gene, andepsD, present in 93 of the 95 starter culture isolates but absent in most of the reference strains. This enabled an unprecedented discrimination of starter cultureLactococcus lactisand revealed substantial differences between the three starter cultures and compositional shifts during the cultivation of cultures in milk.IMPORTANCEIn contemporary cheese production, standardized frozen seed stock starter cultures are used to ensure production stability, reproducibility, and quality control of the product. The dairy industry experiences significant disruptions of cheese production due to phage attacks, and one commonly used countermeasure to phage attack is to employ a starter rotation strategy, in which two or more starters with minimal overlap in phage sensitivity are used alternately. A culture-independent analysis of the lactococcal diversity in complex undefined starter cultures revealed large differences between the three starter cultures and temporal shifts in lactococcal composition during the production of bulk starters. A better understanding of the lactococcal diversity in starter cultures will enable the development of more robust starter cultures and assist in maintaining the efficiency and stability of the production process by ensuring the presence of key bacteria that are important to the characteristics of the product.

scholarly journals Involvement of the LlaKR2I Methylase in Expression of the AbiR Bacteriophage Defense System in Lactococcus lactis subsp. lactis biovar diacetylactis KR2

2006 ◽  
Vol 188 (5) ◽  
pp. 1920-1928 ◽  
Author(s):  
Julie M. Yang ◽  
Patricio J. DeUrraza ◽  
Nadya Matvienko ◽  
Daniel J. O'Sullivan
Keyword(s):  
Cell Cycle ◽  
Lactococcus Lactis ◽  
Protective Role ◽  
Gene Organization ◽  
The Novel ◽  
Genetic Determinants ◽  
Abortive Infection ◽  
Methylase Gene

ABSTRACT The native lactococcal plasmid, pKR223, from Lactococcus lactis subsp. lactis biovar diacetylactis KR2 encodes two distinct bacteriophage-resistant mechanisms, the LlaKR2I restriction and modification (R/M) system and the abortive infection (Abi) mechanism, AbiR, that impedes bacteriophage DNA replication. This study completed the characterization of AbiR, revealing that it is the first Abi system to be encoded by three genes, abiRa, abiRb, and abiRc, arranged in an operon and that it requires the methylase gene from the LlaKR2I R/M system. An analysis of deletion and insertion clones demonstrated that the AbiR operon was toxic in L. lactis without the presence of the LlaKR2I methylase, which is required to protect L. lactis from AbiR toxicity. The novelty of the AbiR system resides in its original gene organization and the unusual protective role of the LlaKR2I methylase. Interestingly, the AbiR genetic determinants are flanked by two IS982 elements generating a likely transposable AbiR composite. This observation not only substantiated the novel function of the LlaKR2I methylase in the AbiR system but also illustrated the evolution of the LlaKR2I methylase toward a new and separate cellular function. This unique structure of both the LlaKR2I R/M system and the AbiR system may have contributed to the evolution of the LlaKR2I methylase toward a novel role comparable to that of the cell cycle-regulated methylases that include Dam and CcrM methylases. This new role for the LlaKR2I methylase offers a unique snapshot into the evolution of the cell cycle-regulated methylases from an existing R/M system.

scholarly journals The relevance of carbon dioxide metabolism in Streptococcus thermophilus

Microbiology ◽  
2009 ◽  
Vol 155 (6) ◽  
pp. 1953-1965 ◽  
Author(s):  
Stefania Arioli ◽  
Paola Roncada ◽  
Anna Maria Salzano ◽  
Francesca Deriu ◽  
Silvia Corona ◽  
...  
Keyword(s):  
Streptococcus Thermophilus ◽  
Defined Medium ◽  
Starter Cultures ◽  
Energy Status ◽  
Carbamoyl Phosphate ◽  
Proteomic Data ◽  
Potential Applications ◽  
High Reduction ◽  
Dairy Starter Cultures

Streptococcus thermophilus is a major component of dairy starter cultures used for the manufacture of yoghurt and cheese. In this study, the CO2 metabolism of S. thermophilus DSM 20617T, grown in either a N2 atmosphere or an enriched CO2 atmosphere, was analysed using both genetic and proteomic approaches. Growth experiments performed in a chemically defined medium revealed that CO2 depletion resulted in bacterial arginine, aspartate and uracil auxotrophy. Moreover, CO2 depletion governed a significant change in cell morphology, and a high reduction in biomass production. A comparative proteomic analysis revealed that cells of S. thermophilus showed a different degree of energy status depending on the CO2 availability. In agreement with proteomic data, cells grown under N2 showed a significantly higher milk acidification rate compared with those grown in an enriched CO2 atmosphere. Experiments carried out on S. thermophilus wild-type and its derivative mutant, which was inactivated in the phosphoenolpyruvate carboxylase and carbamoyl-phosphate synthase activities responsible for fixing CO2 to organic molecules, suggested that the anaplerotic reactions governed by these enzymes have a central role in bacterial metabolism. Our results reveal the capnophilic nature of this micro-organism, underlining the essential role of CO2 in S. thermophilus physiology, and suggesting potential applications in dairy fermentation processes.

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