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Wang Y, Peng Q, Liu Y, Wu N, He Y, Cui X, Dan T. Genomic and transcriptomic analysis of genes involved in exopolysaccharide biosynthesis by Streptococcus thermophilus IMAU20561 grown on different sources of nitrogen. Front Microbiol 2024; 14:1328824. [PMID: 38348305 PMCID: PMC10859522 DOI: 10.3389/fmicb.2023.1328824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/31/2023] [Indexed: 02/15/2024] Open
Abstract
Exopolysaccharides (EPSs), which are produced by lactic acid bacteria, have been found to improve the texture and functionality of fermented dairy products. In a previous study, four nitrogen sources were identified as affecting the yield, molecular weight and structure of EPSs produced by Streptococcus thermophilus IMAU20561 in M17 medium. In this genomic and transcriptomics study, a novel eps gene cluster responsible for assembly of repeating units of EPS is reported. This eps cluster (22.3 kb), consisting of 24 open reading frames, is located in the chromosomal DNA. To explore the biosynthetic mechanisms in EPS, we completed RNA-seq analysis of S. thermophilus IMAU20561 grown in four different nitrogen sources for 5 h (log phase) or 10 h (stationary phase). GO functional annotation showed that there was a significant enrichment of differentially expressed genes (DEGs) involved in: amino acid biosynthesis and metabolism; ribonucleotide biosynthesis and metabolism; IMP biosynthesis and metabolism; and phosphorus metabolism. KEGG functional annotation also indicated enrichment of DEGs involved in amino acid biosynthesis, glycolysis, phosphotransferase system, fructose, and mannose metabolism. Our findings provide a better understanding the genetic traits of S. thermophilus, the biosynthetic pathways needed for the production of EPS, and a theoretical basis for screening dairy starter cultures.
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Affiliation(s)
- Yuenan Wang
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China
- Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China
- Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Qingting Peng
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China
- Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China
- Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Yang Liu
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China
- Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China
- Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Na Wu
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China
- Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China
- Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Yanyan He
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China
- Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China
- Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Xinrui Cui
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China
- Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China
- Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
| | - Tong Dan
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China
- Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China
- Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot, China
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Techawiwattanaboon T, Phanchamnan E, Iadsee N, Makjaroen J, Pisitkun T, Patarakul K. Proteomic profile of naturally released extracellular vesicles secreted from Leptospira interrogans serovar Pomona in response to temperature and osmotic stresses. Sci Rep 2023; 13:18601. [PMID: 37903905 PMCID: PMC10616267 DOI: 10.1038/s41598-023-45863-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 10/25/2023] [Indexed: 11/01/2023] Open
Abstract
Bacterial extracellular vesicles (EVs) are generally formed by pinching off outer membrane leaflets while simultaneously releasing multiple active molecules into the external environment. In this study, we aimed to identify the protein cargo of leptospiral EVs released from intact leptospires grown under three different conditions: EMJH medium at 30 °C, temperature shifted to 37 °C, and physiologic osmolarity (EMJH medium with 120 mM NaCl). The naturally released EVs observed under transmission electron microscopy were spherical in shape with an approximate diameter of 80-100 nm. Quantitative proteomics and bioinformatic analysis indicated that the EVs were formed primarily from the outer membrane and the cytoplasm. The main functional COG categories of proteins carried in leptospiral EVs might be involved in cell growth, survival and adaptation, and pathogenicity. Relative to their abundance in EVs grown in EMJH medium at 30 °C, 39 and 69 proteins exhibited significant changes in response to the temperature shift and the osmotic change, respectively. During exposure to both stresses, Leptospira secreted several multifunctional proteins via EVs, while preserving certain virulence proteins within whole cells. Therefore, leptospiral EVs may serve as a decoy structure for host responses, whereas some virulence factors necessary for direct interaction with the host environment are reserved in leptospiral cells. This knowledge will be useful for understanding the pathogenesis of leptospirosis and developing as one of vaccine platforms against leptospirosis in the future.
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Affiliation(s)
- Teerasit Techawiwattanaboon
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
| | - Eakalak Phanchamnan
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
- Medical Microbiology, Interdisciplinary Program, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Nutta Iadsee
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand
- Medical Microbiology, Interdisciplinary Program, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Jiradej Makjaroen
- Center of Excellence in Systems Biology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Department of Transfusion Medicine and Clinical Microbiology, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Trairak Pisitkun
- Center of Excellence in Systems Biology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Kanitha Patarakul
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
- Chula Vaccine Research Center (Chula VRC), Center of Excellence in Vaccine Research and Development, Chulalongkorn University, Bangkok, Thailand.
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A Genome-Wide CRISPR Interference Screen Reveals an StkP-Mediated Connection between Cell Wall Integrity and Competence in Streptococcus salivarius. mSystems 2022; 7:e0073522. [PMID: 36342134 PMCID: PMC9765292 DOI: 10.1128/msystems.00735-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Competence is one of the most efficient bacterial evolutionary and adaptative strategies by synchronizing production of antibacterial compounds and integration of DNA released by dead cells. In most streptococci, this tactic is orchestrated by the ComRS system, a pheromone communication device providing a short time window of activation in which only part of the population is responsive. Understanding how this developmental process integrates multiple inputs to fine-tune the adequate response is a long-standing question. However, essential genes involved in the regulation of ComRS have been challenging to study. In this work, we built a conditional mutant library using CRISPR interference and performed three complementary screens to investigate competence genetic regulation in the human commensal Streptococcus salivarius. We show that initiation of competence increases upon cell wall impairment, suggesting a connection between cell envelope stress and competence activation. Notably, we report a key role for StkP, a serine-threonine kinase known to regulate cell wall homeostasis. We show that StkP controls competence by a mechanism that reacts to peptidoglycan fragments. Together, our data suggest a key cell wall sensing mechanism coupling competence to cell envelope integrity. IMPORTANCE Survival of human commensal streptococci in the digestive tract requires efficient strategies which must be tightly and collectively controlled for responding to competitive pressure and drastic environmental changes. In this context, the autocrine signaling system ComRS controlling competence for natural transformation and predation in salivarius streptococci could be seen as a multi-input device integrating a variety of environmental stimuli. In this work, we revealed novel positive and negative competence modulators by using a genome-wide CRISPR interference strategy. Notably, we highlighted an unexpected connection between bacterial envelope integrity and competence activation that involves several cell wall sensors. Together, these results showcase how commensal streptococci can fine-tune the pheromone-based competence system by responding to multiple inputs affecting their physiological status in order to calibrate an appropriate collective behavior.
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Jackson SA, Duan M, Zhang P, Ihua MW, Stengel DB, Duan D, Dobson ADW. Isolation, identification, and biochemical characterization of a novel bifunctional phosphomannomutase/phosphoglucomutase from the metagenome of the brown alga Laminaria digitata. Front Microbiol 2022; 13:1000634. [PMID: 36212884 PMCID: PMC9537760 DOI: 10.3389/fmicb.2022.1000634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 08/15/2022] [Indexed: 11/17/2022] Open
Abstract
Macroalgae host diverse epiphytic bacterial communities with potential symbiotic roles including important roles influencing morphogenesis and growth of the host, nutrient exchange, and protection of the host from pathogens. Macroalgal cell wall structures, exudates, and intra-cellular environments possess numerous complex and valuable carbohydrates such as cellulose, hemi-cellulose, mannans, alginates, fucoidans, and laminarin. Bacterial colonizers of macroalgae are important carbon cyclers, acquiring nutrition from living macroalgae and also from decaying macroalgae. Seaweed epiphytic communities are a rich source of diverse carbohydrate-active enzymes which may have useful applications in industrial bioprocessing. With this in mind, we constructed a large insert fosmid clone library from the metagenome of Laminaria digitata (Ochrophyta) in which decay was induced. Subsequent sequencing of a fosmid clone insert revealed the presence of a gene encoding a bifunctional phosphomannomutase/phosphoglucomutase (PMM/PGM) enzyme 10L6AlgC, closely related to a protein from the halophilic marine bacterium, Cobetia sp. 10L6AlgC was subsequently heterologously expressed in Escherichia coli and biochemically characterized. The enzyme was found to possess both PMM and PGM activity, which had temperature and pH optima of 45°C and 8.0, respectively; for both activities. The PMM activity had a Km of 2.229 mM and Vmax of 29.35 mM min−1 mg−1, while the PGM activity had a Km of 0.5314 mM and a Vmax of 644.7 mM min−1 mg−1. Overall characterization of the enzyme including the above parameters as well as the influence of various divalent cations on these activities revealed that 10L6AlgC has a unique biochemical profile when compared to previously characterized PMM/PGM bifunctional enzymes. Thus 10L6AlgC may find utility in enzyme-based production of biochemicals with different potential industrial applications, in which other bacterial PMM/PGMs have previously been used such as in the production of low-calorie sweeteners in the food industry.
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Affiliation(s)
- Stephen A. Jackson
- School of Microbiology, University College Cork, Cork, Ireland
- Environmental Research Institute, University College Cork, Cork, Ireland
| | - Maohang Duan
- Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Pengyan Zhang
- Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Maureen W. Ihua
- School of Microbiology, University College Cork, Cork, Ireland
| | - Dagmar B. Stengel
- Botany and Plant Science, School of Natural Sciences, Ryan Institute for Environmental, Marine and Energy Research, University of Galway, Galway, Ireland
| | - Delin Duan
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- *Correspondence: Delin Duan,
| | - Alan D. W. Dobson
- School of Microbiology, University College Cork, Cork, Ireland
- Environmental Research Institute, University College Cork, Cork, Ireland
- Alan D. W. Dobson,
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Luo M, Liu X, Su H, Li M, Li M, Wei J. Regulatory Networks of Flowering Genes in Angelica sinensis during Vernalization. PLANTS 2022; 11:plants11101355. [PMID: 35631780 PMCID: PMC9144295 DOI: 10.3390/plants11101355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 05/16/2022] [Accepted: 05/18/2022] [Indexed: 11/29/2022]
Abstract
Angelica sinensis is a low-temperature and long-day perennial herb that has been widely used for cardio-cerebrovascular diseases in recent years. In commercial cultivation, up to 40% of flowering decreases the officinal yield of roots and accumulation of bioactive compounds. Although the regulatory mechanism of flowering genes during the photoperiod has been revealed, the networks during vernalization have not been mapped. Here, transcriptomics profiles of A. sinensis with uncompleted (T1), completed (T2) and avoided vernalization (T3) were performed using RNA-seq, and genes expression was validated with qRT-PCR. A total of 61,241 isoforms were annotated on KEGG, KOG, Nr and Swiss-Prot databases; 4212 and 5301 differentially expressed genes (DEGs) were observed; and 151 and 155 genes involved in flowering were dug out at T2 vs. T1 and T3 vs. T1, respectively. According to functional annotation, 104 co-expressed genes were classified into six categories: FLC expression (22; e.g., VILs, FCA and FLK), sucrose metabolism (12; e.g., TPSs, SUS3 and SPSs), hormone response (18; e.g., GID1B, RAP2s and IAAs), circadian clock (2; i.e., ELF3 and COR27), downstream floral integrators and meristem identity (15; e.g., SOC1, AGL65 and SPLs) and cold response (35; e.g., PYLs, ERFs and CORs). The expression levels of candidate genes were almost consistent with FPKM values and changes in sugar and hormone contents. Based on their functions, four pathways that regulate flowering during vernalization were mapped, including the vernalization pathway, the autonomic pathway, the age pathway and the GA (hormone) pathway. This transcriptomic analysis provides new insights into the gene-regulatory networks of flowering in A. sinensis.
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Affiliation(s)
- Mimi Luo
- State Key Laboratory of Aridland Crop Science, College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (M.L.); (X.L.); (H.S.); (M.L.)
| | - Xiaoxia Liu
- State Key Laboratory of Aridland Crop Science, College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (M.L.); (X.L.); (H.S.); (M.L.)
| | - Hongyan Su
- State Key Laboratory of Aridland Crop Science, College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (M.L.); (X.L.); (H.S.); (M.L.)
| | - Meiling Li
- State Key Laboratory of Aridland Crop Science, College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (M.L.); (X.L.); (H.S.); (M.L.)
| | - Mengfei Li
- State Key Laboratory of Aridland Crop Science, College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (M.L.); (X.L.); (H.S.); (M.L.)
- Correspondence: (M.L.); (J.W.)
| | - Jianhe Wei
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100193, China
- Correspondence: (M.L.); (J.W.)
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Xu L, Wang F, Zhang Z, Terry N. Optimization of Polysaccharide Production from Cordyceps militaris by Solid-State Fermentation on Rice and Its Antioxidant Activities. Foods 2019; 8:foods8110590. [PMID: 31752388 PMCID: PMC6915433 DOI: 10.3390/foods8110590] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 10/29/2019] [Accepted: 11/14/2019] [Indexed: 11/16/2022] Open
Abstract
Polysaccharides are an important class of bioactive components of medical mushroom and herbs and are now used as natural drugs or dietary supplements on a global scale. In this paper, we aimed to increase the polysaccharide production of Cordyceps militaris and the antioxidant activities of fermented rice by solid-state fermentation. The media components and culture condition were optimized by orthogonal design and mono-factor tests using rice as the raw material. The optimal media consisted of (g/L): rice (50), fructose (7), glycerin (7), peptone (1), MgCl2 (0.11), VB1 (0.05), VB2 (0.05), CaCl2 (1.5), corn bran (6), and a water-materials ratio of 100%. The fermentation condition was as follows: inoculum volume of 5.5% (v/w), rice weight of 50 g in one bowl with a diameter of 120 mm and a depth of 90 mm, incubation temperature of 26 °C, and incubation time of seven days. Under the optimized condition, the maximal C. militaris polysaccharide content and free radical scavenging ratio were 68.3 mg/g dry substrate and 98.9%, respectively. This study provides a new strategy for the production of healthy food from traditional food.
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Affiliation(s)
- Ling Xu
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; (L.X.); (Z.Z.)
- Institute of Food Physical Processing, Jiangsu University, Zhenjiang 212013, China
| | - Feng Wang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; (L.X.); (Z.Z.)
- Institute of Food Physical Processing, Jiangsu University, Zhenjiang 212013, China
- Correspondence: ; Tel.: +86-511-8878-0201
| | - Zhicai Zhang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; (L.X.); (Z.Z.)
- Institute of Agro-production Processing Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Norman Terry
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA;
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Zhang N, Tang Z, Zhang J, Li X, Yang Z, Yang C, Zhang Z, Huang Z. Comparative transcriptome analysis reveals the genetic basis underlying the biosynthesis of polysaccharides in Hericium erinaceus. BOTANICAL STUDIES 2019; 60:15. [PMID: 31363932 PMCID: PMC6667577 DOI: 10.1186/s40529-019-0263-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 07/16/2019] [Indexed: 05/05/2023]
Abstract
BACKGROUND Hericium erinaceus, also known as lion's mane mushroom, is a widely distributed edible and medicinal fungus in Asian countries. H. erinaceus harbors diverse bioactive metabolites with anticancer, immunomodulating, anti-inflammatory, antimicrobial, antihypertensive, antidiabetic and neuroprotective properties. Although the chemical synthesis processes of these bioactive metabolites are known, the biosynthetic processes remain unknown. RESULTS In this study, we obtained the transcriptomes of six H. erinaceus strains using next-generation RNA sequencing and investigated the characteristics of the transcriptomes and biosynthesis of bioactive compounds, especially polysaccharides. The transcriptomes ranged in size from 46.58 to 58.14 Mb, with the number of unigenes ranging from 20,902 to 37,259 across the six H. erinaceus strains. Approximately 60% of the unigenes were successfully annotated by comparing sequences against different databases, including the nonredundant (NR), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), clusters of orthologous groups for eukaryotic complete genomes (KOG) and Swiss-Prot databases. Most of the transcripts were putatively involved in signal transduction, carbohydrate metabolism, translation, transport and catabolism, and amino acid metabolism. Genes involved in polysaccharide biosynthesis were identified, and these genes encoded phosphoglucomutase (PGM), glucose phosphate isomerase (PGI), UDP-glucose pyrophosphorylase (UGP), glycoside hydrolase family proteins, glycosyltransferase family proteins and other proteins. Moreover, the putative pathway for the intracellular polysaccharide biosynthesis of H. erinaceus was analyzed. Additionally, the open reading frames (ORFs) and simple sequence repeats (SSRs) were predicted from the transcriptome data of the six strains. CONCLUSIONS Overall, the present study may facilitate the discovery of polysaccharide biosynthesis processes in H. erinaceus and provide useful information for exploring the secondary metabolites in other members of the Basidiomycetes genus.
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Affiliation(s)
- Nan Zhang
- College of Life Sciences, Neijiang Normal University, Neijiang, 641100 People’s Republic of China
- Key Laboratory of Regional Characteristic Agricultural Resources, Department of Education, Neijiang, 641100 People’s Republic of China
| | - Zongfu Tang
- College of Life Sciences, Neijiang Normal University, Neijiang, 641100 People’s Republic of China
| | - Jun Zhang
- College of Life Sciences, Neijiang Normal University, Neijiang, 641100 People’s Republic of China
| | - Xin Li
- College of Life Sciences, Neijiang Normal University, Neijiang, 641100 People’s Republic of China
| | - Ziqian Yang
- College of Life Sciences, Neijiang Normal University, Neijiang, 641100 People’s Republic of China
| | - Chun Yang
- College of Life Sciences, Neijiang Normal University, Neijiang, 641100 People’s Republic of China
| | - Zhaofeng Zhang
- College of Life Sciences, Neijiang Normal University, Neijiang, 641100 People’s Republic of China
| | - Zuoxi Huang
- College of Life Sciences, Neijiang Normal University, Neijiang, 641100 People’s Republic of China
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Suryaletha K, Narendrakumar L, John J, Radhakrishnan MP, George S, Thomas S. Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants. BMC Microbiol 2019; 19:146. [PMID: 31253082 PMCID: PMC6599329 DOI: 10.1186/s12866-019-1527-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 06/20/2019] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Enterococcus faecalis is a major clinically relevant nosocomial bacterial pathogen frequently isolated from polymicrobial infections. The biofilm forming ability of E. faecalis attributes a key role in its virulence and drug resistance. Biofilm cells are phenotypically and metabolically different from their planktonic counterparts and many aspects involved in E. faecalis biofilm formation are yet to be elucidated. The strain E. faecalis SK460 used in the present study is esp (Enterococcal surface protein) and fsr (two-component signal transduction system) negative non-gelatinase producing strong biofilm former isolated from a chronic diabetic foot ulcer patient. We executed a label-free quantitative proteomic approach to elucidate the differential protein expression pattern at planktonic and biofilm stages of SK460 to come up with potential determinants associated with Enterococcal biofilm formation. RESULTS The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of proteomic data revealed that biofilm cells expressed higher levels of proteins which are associated with glycolysis, amino acid biosynthesis, biosynthesis of secondary metabolites, microbial metabolism in diverse environments and stress response factors. Besides these basic survival pathways, LuxS-mediated quorum sensing, arginine metabolism, rhamnose biosynthesis, pheromone and adhesion associated proteins were found to be upregulated during the biofilm transit from planktonic stages. The selected subsets were validated by quantitative real-time PCR. In silico functional interaction analysis revealed that the genes involved in upregulated pathways pose a close molecular interaction thereby coordinating the regulatory network to thrive as a biofilm community. CONCLUSIONS The present study describes the first report of the quantitative proteome analysis of an esp and fsr negative non gelatinase producing E. faecalis. Proteome analysis evidenced enhanced expression of glycolytic pathways, stress response factors, LuxS quorum signaling system, rhamnopolysaccharide synthesis and pheromone associated proteins in biofilm phenotype. We also pointed out the relevance of LuxS quorum sensing and pheromone associated proteins in the biofilm development of E. faecalis which lacks the Fsr quorum signaling system. These validated biofilm determinants can act as potential inhibiting targets in Enterococcal infections.
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Affiliation(s)
- Karthika Suryaletha
- Cholera and Biofilm Research Laboratory, Pathogen Biology, Rajiv Gandhi Centre for Biotechnology, (National Institute under the Department of Biotechnology, Government of India), Trivandrum, Kerala, 695014, India
| | - Lekshmi Narendrakumar
- Cholera and Biofilm Research Laboratory, Pathogen Biology, Rajiv Gandhi Centre for Biotechnology, (National Institute under the Department of Biotechnology, Government of India), Trivandrum, Kerala, 695014, India
| | - Joby John
- Department of Surgery, Government Medical College Hospital, Trivandrum, Kerala, 695011, India
| | - Megha Periyappilly Radhakrishnan
- Cholera and Biofilm Research Laboratory, Pathogen Biology, Rajiv Gandhi Centre for Biotechnology, (National Institute under the Department of Biotechnology, Government of India), Trivandrum, Kerala, 695014, India
| | - Sanil George
- Interdisciplinary Biology, Rajiv Gandhi Centre for Biotechnology, Trivandrum, Kerala, 695014, India
| | - Sabu Thomas
- Cholera and Biofilm Research Laboratory, Pathogen Biology, Rajiv Gandhi Centre for Biotechnology, (National Institute under the Department of Biotechnology, Government of India), Trivandrum, Kerala, 695014, India.
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Giaretta S, Treu L, Vendramin V, da Silva Duarte V, Tarrah A, Campanaro S, Corich V, Giacomini A. Comparative Transcriptomic Analysis of Streptococcus thermophilus TH1436 and TH1477 Showing Different Capability in the Use of Galactose. Front Microbiol 2018; 9:1765. [PMID: 30131781 PMCID: PMC6090898 DOI: 10.3389/fmicb.2018.01765] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 07/16/2018] [Indexed: 12/03/2022] Open
Abstract
Streptococcus thermophilus is a species widely used in the dairy industry for its capability to rapidly ferment lactose and lower the pH. The capability to use galactose produced from lactose hydrolysis is strain dependent and most of commercial S. thermophilus strains are galactose-negative (Gal−), although galactose-positive (Gal+) would be more technologically advantageous because this feature could provide additional metabolic products and prevent galactose accumulation in foods. In this study, a next generation sequencing transcriptome approach was used to compare for the first time a Gal+ and a Gal− strain to characterize their whole metabolism and shed light on their different properties, metabolic performance and gene regulation. Transcriptome analysis revealed that all genes of the gal operon were expressed very differently in Gal+ and in the Gal− strains. The expression of several genes involved in mixed acid fermentation, PTS sugars transporter and stress response were found enhanced in Gal+. Conversely, genes related to amino acids, proteins metabolism and CRISPR associated proteins were under-expressed. In addition, the strains showed a diverse series of predicted genes controlled by the transcriptional factor catabolite control protein A (CcpA). Overall, transcriptomic analysis suggests that the Gal+ strain underwent a metabolic remodeling to cope with the changed environmental conditions.
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Affiliation(s)
- Sabrina Giaretta
- Department of Agronomy Food Natural Resources Animal and Environment, University of Padova, Padova, Italy
| | - Laura Treu
- Department of Agronomy Food Natural Resources Animal and Environment, University of Padova, Padova, Italy.,Department of Environmental Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Veronica Vendramin
- Department of Agronomy Food Natural Resources Animal and Environment, University of Padova, Padova, Italy
| | | | - Armin Tarrah
- Department of Agronomy Food Natural Resources Animal and Environment, University of Padova, Padova, Italy
| | | | - Viviana Corich
- Department of Agronomy Food Natural Resources Animal and Environment, University of Padova, Padova, Italy
| | - Alessio Giacomini
- Department of Agronomy Food Natural Resources Animal and Environment, University of Padova, Padova, Italy
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Technological properties assessment and two component systems distribution of Streptococcus thermophilus strains isolated from fermented milk. Arch Microbiol 2017; 200:567-580. [PMID: 29236144 DOI: 10.1007/s00203-017-1468-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 11/25/2017] [Accepted: 12/06/2017] [Indexed: 10/18/2022]
Abstract
Streptococcus thermophilus is one of the economically most representatives of lactic acid bacteria, which is widely used as a starter to produce fermented milk products. In this study, 22 S. thermophilus strains were isolated from 26 fermented milk samples. Most isolates showed the ability to ferment a broad range of carbohydrates. Interestingly, eight strains are galactose positive, which is a desirable property in various industrial dairy fermentations. Four different nucleotide sequences were found in the galR-galK intergenic regions. The 16S-23S intergenic spacer region sequences of most isolates were determined as ITS-St-II type, which are related with protease positive and fast acidification. CS18 presented excellent technological performances, and showed potential as a promising starter candidate. To gain a comprehensive view of stress response mechanisms of strains, the distribution of all the two-component systems (TCSs) in strains were investigated. TCS analysis indicated that the nucleotide sequence of TCSs have obvious differences in different strains. And the strains with the special nucleotide sequences of TCS have distinctive traits. Therefore, it was speculated that there is a certain connection between the traits' difference and the TCS difference of strains.
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11
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Ding Q, Tan KS. Himar1 Transposon for Efficient Random Mutagenesis in Aggregatibacter actinomycetemcomitans. Front Microbiol 2017; 8:1842. [PMID: 29018421 PMCID: PMC5622930 DOI: 10.3389/fmicb.2017.01842] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 09/08/2017] [Indexed: 12/14/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans is the primary etiological agent of aggressive periodontal disease. Identification of novel virulence factors at the genome-wide level is hindered by lack of efficient genetic tools to perform mutagenesis in this organism. The Himar1 mariner transposon is known to yield a random distribution of insertions in an organism’s genome with requirement for only a TA dinucleotide target and is independent of host-specific factors. However, the utility of this system in A. actinomycetemcomitans is unknown. In this study, we found that Himar1 transposon mutagenesis occurs at a high frequency (×10-4), and can be universally applied to wild-type A. actinomycetemcomitans strains of serotypes a, b, and c. The Himar1 transposon inserts were stably inherited in A. actinomycetemcomitans transconjugants in the absence of antibiotics. A library of 16,000 mutant colonies of A. actinomycetemcomitans was screened for reduced biofilm formation. Mutants with transposon inserts in genes encoding pilus, putative ion transporters, multidrug resistant proteins, transcription regulators and enzymes involved in the synthesis of extracellular polymeric substance, bacterial metabolism and stress response were discovered in this screen. Our results demonstrated the utility of the Himar1 mutagenesis system as a novel genetic tool for functional genomic analysis in A. actinomycetemcomitans.
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Affiliation(s)
- Qinfeng Ding
- Faculty of Dentistry, National University of Singapore, Singapore, Singapore
| | - Kai Soo Tan
- Faculty of Dentistry, National University of Singapore, Singapore, Singapore
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12
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Xu CG, Yang YB, Zhou YH, Hao MQ, Ren YZ, Wang XT, Chen JQ, Muhammad I, Wang S, Liu D, Li XB, Li YH. Comparative Proteomic Analysis Provides insight into the Key Proteins as Possible Targets Involved in Aspirin Inhibiting Biofilm Formation of Staphylococcus xylosus. Front Pharmacol 2017; 8:543. [PMID: 28871227 PMCID: PMC5566577 DOI: 10.3389/fphar.2017.00543] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 08/04/2017] [Indexed: 01/01/2023] Open
Abstract
Staphylococcus xylosus is an opportunistic pathogen that causes infection in humans and cow mastitis. And S. xylosus possesses a strong ability to form biofilms in vitro. As biofilm formation facilitates resistance to antimicrobial agents, the discovery of new medicinal properties for classic drugs is highly desired. Aspirin, which is the most common active component of non-steroidal anti-inflammatory compounds, affects the biofilm-forming capacity of various bacterial species. We have found that aspirin effectively inhibits biofilm formation of S. xylosus by Crystal violet (CV) staining and scanning electron microscopy analyses. The present study sought to elucidate possible targets of aspirin in suppressing S. xylosus biofilm formation. Based on an isobaric tag for relative and absolute quantitation (iTRAQ) fold-change of >1.2 or <0.8 (P-value < 0.05), 178 differentially expressed proteins, 111 down-regulated and 67 up-regulated, were identified after application of aspirin to cells at a 1/2 minimal inhibitory concentration. Gene ontology analysis indicated enrichment in metabolic processes for the majority of the differentially expressed proteins. We then used the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database to analyze a large number of differentially expressed proteins and identified genes involved in biosynthesis of amino acids pathway, carbon metabolism (pentose phosphate and glycolytic pathways, tricarboxylic acid cycle) and nitrogen metabolism (histidine metabolism). These novel proteins represent candidate targets in aspirin-mediated inhibition of S. xylosus biofilm formation at sub-MIC levels. The findings lay the foundation for further studies to identify potential aspirin targets.
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Affiliation(s)
- Chang-Geng Xu
- College of Veterinary Medicine, Northeast Agricultural UniversityHarbin, China
| | - Yan-Bei Yang
- College of Veterinary Medicine, Northeast Agricultural UniversityHarbin, China
| | - Yong-Hui Zhou
- College of Veterinary Medicine, Northeast Agricultural UniversityHarbin, China
| | - Mei-Qi Hao
- College of Veterinary Medicine, Northeast Agricultural UniversityHarbin, China
| | - Yong-Zhi Ren
- College of Veterinary Medicine, Northeast Agricultural UniversityHarbin, China
| | - Xiao-Ting Wang
- College of Veterinary Medicine, Northeast Agricultural UniversityHarbin, China
| | - Jian-Qing Chen
- College of Veterinary Medicine, Northeast Agricultural UniversityHarbin, China
| | - Ishfaq Muhammad
- College of Veterinary Medicine, Northeast Agricultural UniversityHarbin, China
| | - Shuai Wang
- College of Veterinary Medicine, Northeast Agricultural UniversityHarbin, China
| | - Di Liu
- Heilongjiang Academy of Agricultural SciencesHarbin, China
| | - Xiu-Bo Li
- Feed Research Institute, Chinese Academy of Agricultural SciencesBeijing, China
| | - Yan-Hua Li
- College of Veterinary Medicine, Northeast Agricultural UniversityHarbin, China
- Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical DevelopmentHarbin, China
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13
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Zeidan AA, Poulsen VK, Janzen T, Buldo P, Derkx PMF, Øregaard G, Neves AR. Polysaccharide production by lactic acid bacteria: from genes to industrial applications. FEMS Microbiol Rev 2017; 41:S168-S200. [DOI: 10.1093/femsre/fux017] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 03/29/2017] [Indexed: 01/14/2023] Open
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14
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New advances in exopolysaccharides production of Streptococcus thermophilus. Arch Microbiol 2017; 199:799-809. [PMID: 28357474 DOI: 10.1007/s00203-017-1366-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Revised: 03/12/2017] [Accepted: 03/15/2017] [Indexed: 10/19/2022]
Abstract
Streptococcus thermophilus is the most important thermophilic dairy starter, and is widely used in the dairy industry. Streptococcus thermophilus exopolysaccharides received wide attention over recent decades, because they can improve the properties of the dairy product and confer beneficial health effects. The understanding of the regulatory and biosynthetic mechanisms of EPS will improve the EPS biosynthesis, increase the productivity of EPSs, and develop EPSs with desirable properties. The structure of EPSs is the focus of this study. Revealing the structure-function relationship can lead to increase the knowledge base and from there to increased research of EPS. The EPS yield is a key limiting factor in the research and utilization of EPS. In the present review, biosynthetic pathways and genetics of S. thermophilus EPSs were described and reviewed. At the same time, functional properties and applications of EPS, and strategies for enhancement of EPS production are discussed.
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15
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New Insights into Various Production Characteristics of Streptococcus thermophilus Strains. Int J Mol Sci 2016; 17:ijms17101701. [PMID: 27754312 PMCID: PMC5085733 DOI: 10.3390/ijms17101701] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/19/2016] [Accepted: 09/23/2016] [Indexed: 01/01/2023] Open
Abstract
Streptococcus thermophilus is one of the most valuable homo-fermentative lactic acid bacteria, which, for a long time, has been widely used as a starter for the production of fermented dairy products. The key production characteristics of S. thermophilus, for example the production of extracellular polysaccharide, proteolytic enzymes and flavor substances as well as acidifying capacity etc., have an important effect on the quality of dairy products. The acidification capacity of the strains determines the manufacturing time and quality of dairy products. It depends on the sugar utilization ability of strains. The production of extracellular polysaccharide is beneficial for improving the texture of dairy products. Flavor substances increase the acceptability of dairy products. The proteolytic activity of the strain influences not only the absorption of the nitrogen source, but also the formation of flavor substances. Different strains have obvious differences in production characteristics via long-time evolution and adaptation to environment. Gaining new strains with novel and desirable characteristics is an important long-term goal for researchers and the fermenting industry. The understanding of the potential molecular mechanisms behind important characteristics of different strains will promote the screening and breeding of excellent strains. In this paper, key technological and functional properties of different S. thermophilus strains are discussed, including sugar metabolism, proteolytic system and amino acid metabolism, and polysaccharide and flavor substance biosynthesis. At the same time, diversity of genomes and plasmids of S. thermophilus are presented. Advances in research on key production characteristics and molecular levels of S. thermophilus will increase understanding of molecular mechanisms of different strains with different important characteristics, and improve the industrialization control level for fermented foods.
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Delannoy CMJ, Zadoks RN, Crumlish M, Rodgers D, Lainson FA, Ferguson HW, Turnbull J, Fontaine MC. Genomic comparison of virulent and non-virulent Streptococcus agalactiae in fish. JOURNAL OF FISH DISEASES 2016; 39:13-29. [PMID: 25399660 DOI: 10.1111/jfd.12319] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 09/05/2014] [Accepted: 09/06/2014] [Indexed: 06/04/2023]
Abstract
Streptococcus agalactiae infections in fish are predominantly caused by beta-haemolytic strains of clonal complex (CC) 7, notably its namesake sequence type (ST) 7, or by non-haemolytic strains of CC552, including the globally distributed ST260. In contrast, CC23, including its namesake ST23, has been associated with a wide homeothermic and poikilothermic host range, but never with fish. The aim of this study was to determine whether ST23 is virulent in fish and to identify genomic markers of fish adaptation of S. agalactiae. Intraperitoneal challenge of Nile tilapia, Oreochromis niloticus (Linnaeus), showed that ST260 is lethal at doses down to 10(2) cfu per fish, whereas ST23 does not cause disease at 10(7) cfu per fish. Comparison of the genome sequence of ST260 and ST23 with those of strains derived from fish, cattle and humans revealed the presence of genomic elements that are unique to subpopulations of S. agalactiae that have the ability to infect fish (CC7 and CC552). These loci occurred in clusters exhibiting typical signatures of mobile genetic elements. PCR-based screening of a collection of isolates from multiple host species confirmed the association of selected genes with fish-derived strains. Several fish-associated genes encode proteins that potentially provide fitness in the aquatic environment.
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Affiliation(s)
- C M J Delannoy
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, UK
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
| | - R N Zadoks
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - M Crumlish
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, UK
| | - D Rodgers
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
| | - F A Lainson
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
| | - H W Ferguson
- School of Veterinary Medicine, St. George's University, St. George's, Grenada, West Indies
| | - J Turnbull
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, UK
| | - M C Fontaine
- Moredun Research Institute, Pentlands Science Park, Penicuik, UK
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17
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Zhu ZY, Liu XC, Dong FY, Guo MZ, Wang XT, Wang Z, Zhang YM. Influence of fermentation conditions on polysaccharide production and the activities of enzymes involved in the polysaccharide synthesis of Cordyceps militaris. Appl Microbiol Biotechnol 2015; 100:3909-21. [DOI: 10.1007/s00253-015-7235-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 12/02/2015] [Accepted: 12/05/2015] [Indexed: 10/22/2022]
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18
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Characterization and upregulation of bifunctional phosphoglucomutase/phosphomannomutase enzyme in an exobiopolymer overproducing strain of Acinetobacter haemolyticus. Microbiol Res 2015; 181:8-14. [PMID: 26640047 DOI: 10.1016/j.micres.2015.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Revised: 07/13/2015] [Accepted: 08/04/2015] [Indexed: 11/24/2022]
Abstract
Several members of the Acinetobacter spp. produce exobiopolymer (EBP) of considerable biotechnological interest. In a previous study, we reported phosphate removal capacity of EBP produced by Acinetobacter haemolyticus. Insertional mutagenesis was attempted to develop EBP-overproducing strains of A. haemolyticus and mutant MG606 was isolated. In order to understand the underlying mechanism of overproduction, the EBP overproducing mutant MG606 was analyzed and compared with the wild type counterpart for its key EBP synthetic enzymes. The EBP produced by MG606 mutant was 650 mg/L compared to 220 mg/L in its wild type counterpart. Significantly high (p<0.05) levels of phosphoglucomutase/phosphomannomutase (PGM/PMM) in MG606 mutant was noted, whereas activities of other enzymes responsible for EBP synthesis showed no significant change (p>0.05). The up-regulation of PGM/PMM expression in mutant was further confirmed by real time reverse transcriptase (RT)-PCR of PGM/PMM transcripts. The optimal conditions for PGM/PMM activity were found to be 35 °C and pH 7.5; PGM/PMM activity was inhibited by ions such as lithium, zinc, nickel. Further, incubation of cells with a PGM inhibitor (lithium) resulted in a concentration-dependent decrease in EBP production further confirming the role of PGM/PMM overexpression in enhanced EBP production by the mutant. Overall the results of our study indicate a key role of PGM/PMM in enhanced EBP production, as evident from enhanced enzyme activity, increased PGM/PMM transcripts and reduction in EBP synthesis by a PGM inhibitor. We envisage a potential exploitation of the insights so obtained to effectively engineer strains of Acinetobacter for overproducing phosphate binding EBP.
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19
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Li N, Wang Y, Zhu P, Liu Z, Guo B, Ren J. Improvement of exopolysaccharide production in Lactobacillus casei LC2W by overexpression of NADH oxidase gene. Microbiol Res 2015; 171:73-7. [DOI: 10.1016/j.micres.2014.12.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 11/22/2014] [Accepted: 12/14/2014] [Indexed: 10/24/2022]
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20
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Wu Q, Cheung CK, Shah NP. Towards galactose accumulation in dairy foods fermented by conventional starter cultures: Challenges and strategies. Trends Food Sci Technol 2015. [DOI: 10.1016/j.tifs.2014.08.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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21
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Woo SH, Park SI. Effects of phosphoglucomutase gene (PGM) in Streptococcus parauberis on innate immune response and pathogenicity of olive flounder (Paralichthys olivaceus). FISH & SHELLFISH IMMUNOLOGY 2014; 41:317-325. [PMID: 25240979 DOI: 10.1016/j.fsi.2014.09.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 08/26/2014] [Accepted: 09/10/2014] [Indexed: 06/03/2023]
Abstract
In recent years, Streptococcus parauberis infection has been an emerging problem in aquaculture in South Korea because of its more frequent isolation than other streptococcal bacteria including Streptococcus iniae. To develop effective treatment and prophylaxis methods against this emerging disease by S. parauberis, it is necessary to understand the underlying pathogenic mechanisms. To uncover the pathogenicity, the mutant strain of S. parauberis with a deleted phosphoglucomutase (PGM) gene which has been known to be an important virulence factor in bacterial pathogens was generated to investigate the relationship between virulence and gene function using an allelic exchange mutagenesis method. Allelic exchange mutagenesis of the phosphoglucomutase gene resulted in phenotype changes including decreased extracellular capsules, reduced buoyancy, increased hydrophobicity and reduced growth. Moreover, the S. parauberis mutant was more sensitive to innate immune clearance mechanisms including serum, mucus and phagocyte killing and could not induce mortality in olive flounder. These phenotype changes and the attenuated virulence of the pathogen to fish could be due to the reduction in capsule production by mutation of the PGM gene. The results provide evidences that phosphoglucomutase expression contributes to S. parauberis virulence in fish by affecting bacterial survival against the host's humoral and cellular defense mechanisms.
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Affiliation(s)
- Sung Ho Woo
- Institute of Fisheries Sciences, Pukyong National University, 474, Ilgwang-Ro, Ilgwang-myeon, Gijang-gun, Busan 619-911, South Korea; Department of Aquatic Life Medicine, Pukyong National University, 45, Yongso-ro, Namgu, Busan 608-737, South Korea.
| | - Soo Il Park
- Department of Aquatic Life Medicine, Pukyong National University, 45, Yongso-ro, Namgu, Busan 608-737, South Korea.
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Chen WY, Marcellin E, Steen JA, Nielsen LK. The role of hyaluronic acid precursor concentrations in molecular weight control in Streptococcus zooepidemicus. Mol Biotechnol 2014; 56:147-56. [PMID: 23903961 DOI: 10.1007/s12033-013-9690-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The biosynthetic pathway responsible for the production of hyaluronic acid (HA) has been thoroughly studied; however, many aspects remain elusive regarding the mechanisms that control molecular weight (MW). Previously, we demonstrated a positive correlation between MW and the concentration of the HA precursor sugar UDP-N acetylglucosamine (UDP-GlcNAc). To further investigate the role of UDP-GlcNAc in MW control, we increased the intracellular concentration of this monomer using both feeding strategies and genetic engineering approaches. Feeding cells glucosamine dramatically increased intracellular levels of UDP-GlcNAc, but unexpectedly, produced HA of a lower MW. This was subsequently attributed to an equally dramatic decrease in the level of the other HA precursor sugar UDP-glucuronic acid (UDP-GlcUA). Feeding cells a mixture of glucose and GlcNAc addressed this imbalance of precursor sugars, leading to an increase in both UDP-GlcNAc and UDP-GlcUA; however, no significant increase in MW was observed. Despite the increase in UDP-sugars, RNA sequencing identified no increase in the expression of the genes involved in production of HA. Returning to genetic engineering approaches to examine UDP-GlcNAc and MW, genes known to contribute to the production of UDP-GlcNAc were over-expressed, both individually and together. Using this approach, UDP-GlcNAc and MW increased. At lower levels of UDP-GlcNAc, the positive correlation between UDP-GlcNAc levels and MW was maintained, however this relationship stalled at higher concentrations of UDP-GlcNAc. Taken together, these results suggest that while optimising HA precursor levels using feeding or genetic engineering approaches can improve HA MW, there is a point at which excess availability of precursors is no longer advantageous. Once precursor concentrations are addressed, it would seem that other uncharacterised factor(s) (e.g. rate of HA synthesis) also contribute to HA MW control.
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Affiliation(s)
- Wendy Yiting Chen
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, 4072, Australia
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Kim HR, Park SY, Kim SB, Jeong H, Choi SK, Park SH. Inactivation of the phosphoglucomutase gene pgm in Paenibacillus polymyxa leads to overproduction of fusaricidin. ACTA ACUST UNITED AC 2014; 41:1405-14. [DOI: 10.1007/s10295-014-1470-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 05/28/2014] [Indexed: 11/29/2022]
Abstract
Abstract
Fusaricidin, a lipodepsipeptide isolated from Paenibacillus polymyxa, has high antimicrobial activity against fungi and Gram-positive bacteria. Through mutagenesis, we obtained two mutant strains, N1U7 and N17U7, which produce 6.2- to 7.9-fold more fusaricidin than their parent strain. Causal mutations were identified by whole-genome sequencing, and the two strains each contained at least eleven point mutations, including four common mutations. A mutation in the PPE04441 gene (pgm), encoding an α-phosphoglucomutase, was found to be an important factor in fusaricidin overproduction by complementation experiments. Null mutation of pgm in the parental strain increased fusaricidin production by 5.2-fold. Increased growth and cell viability in stationary phase, reduced exopolysaccharide production, and increased fusA expression were observed in the pgm mutant strains, which might be related to fusaricidin overproduction. This is the first report revealing that PGM deficiency leads to an overproduction of fusaricidin.
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Affiliation(s)
- Ha-Rim Kim
- grid.249967.7 0000000406363099 Super-Bacteria Research Center Korea Research Institute of Bioscience and Biotechnology (KRIBB) 125 Gwahak-ro 305-806 Daejeon Yuseong-gu Republic of Korea
- grid.412786.e 0000000417918264 Biosystems and Bioengineering Program Korea University of Science and Technology (UST) 217 Gajung-ro 305-350 Daejeon Yuseong-gu Republic of Korea
| | - Soo-Young Park
- grid.249967.7 0000000406363099 Super-Bacteria Research Center Korea Research Institute of Bioscience and Biotechnology (KRIBB) 125 Gwahak-ro 305-806 Daejeon Yuseong-gu Republic of Korea
| | - Seong-Bin Kim
- grid.249967.7 0000000406363099 Super-Bacteria Research Center Korea Research Institute of Bioscience and Biotechnology (KRIBB) 125 Gwahak-ro 305-806 Daejeon Yuseong-gu Republic of Korea
| | - Haeyoung Jeong
- grid.249967.7 0000000406363099 Korean Bioinformation Center, KRIBB 125 Gwahak-ro 305-806 Daejeon Yuseong-gu Republic of Korea
- grid.412786.e 0000000417918264 Biosystems and Bioengineering Program Korea University of Science and Technology (UST) 217 Gajung-ro 305-350 Daejeon Yuseong-gu Republic of Korea
| | - Soo-Keun Choi
- grid.249967.7 0000000406363099 Super-Bacteria Research Center Korea Research Institute of Bioscience and Biotechnology (KRIBB) 125 Gwahak-ro 305-806 Daejeon Yuseong-gu Republic of Korea
- grid.412786.e 0000000417918264 Biosystems and Bioengineering Program Korea University of Science and Technology (UST) 217 Gajung-ro 305-350 Daejeon Yuseong-gu Republic of Korea
| | - Seung-Hwan Park
- grid.249967.7 0000000406363099 Super-Bacteria Research Center Korea Research Institute of Bioscience and Biotechnology (KRIBB) 125 Gwahak-ro 305-806 Daejeon Yuseong-gu Republic of Korea
- grid.412786.e 0000000417918264 Biosystems and Bioengineering Program Korea University of Science and Technology (UST) 217 Gajung-ro 305-350 Daejeon Yuseong-gu Republic of Korea
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Buckley AA, Faustoferri RC, Quivey RG. β-Phosphoglucomutase contributes to aciduricity in Streptococcus mutans. MICROBIOLOGY-SGM 2014; 160:818-827. [PMID: 24509501 DOI: 10.1099/mic.0.075754-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Streptococcus mutans encounters an array of sugar moieties within the oral cavity due to a varied human diet. One such sugar is β-d-glucose 1-phosphate (βDG1P), which must be converted to glucose 6-phosphate (G6P) before further metabolism to lactic acid. The conversion of βDG1P to G6P is mediated by β-phosphoglucomutase, which has not been previously observed in any oral streptococci, but has been extensively characterized and the gene designated pgmB in Lactococcus lactis. An orthologue was identified in S. mutans, SMU.1747c, and deletion of the gene resulted in the inability of the deletion strain to convert βDG1P to G6P, indicating that SMU.1747c is a β-phosphoglucomutase and should be designated pgmB. In this study, we sought to characterize how deletion of pgmB affected known virulence factors of S. mutans, specifically acid tolerance. The ΔpgmB strain showed a decreased ability to survive acid challenge. Additionally, the strain lacking β-phosphoglucomutase had a diminished glycolytic profile compared with the parental strain. Deletion of pgmB had a negative impact on the virulence of S. mutans in the Galleria mellonella (greater wax worm) animal model. Our results indicate that pgmB plays a role at the juncture of carbohydrate metabolism and virulence.
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Affiliation(s)
- Andrew A Buckley
- Department of Microbiology & Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Roberta C Faustoferri
- Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Robert G Quivey
- Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.,Department of Microbiology & Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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25
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Kanmani P, Satish Kumar R, Yuvaraj N, Paari KA, Pattukumar V, Arul V. Probiotics and its functionally valuable products-a review. Crit Rev Food Sci Nutr 2013; 53:641-58. [PMID: 23627505 DOI: 10.1080/10408398.2011.553752] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
During the past two decades probiotic bacteria have been increasingly proposed as health promoting bacteria in variety of food system, because of its safety, functional, and technological characteristics. Commonly, Lactobacillus spp., Bifidobacterium spp., Saccharomyces boulardii, and some other microorganisms have been considered as probiotic strains. Possibly these bacterial strains exerted several beneficial effects into gastrointestinal tract of host while administered with variety of food system. Lactic acid bacteria (LAB) usually produce antimicrobial substances like bacteriocin which have broad spectrum of antagonist effect against closely related Gram positive and Gram negative pathogens. LAB strains often produce polymeric substances such as exopolysaccharides (EPS) which increase the colonization of probiotic bacteria by cell-cell interactions in gastrointestinal tract. LAB also produces biosurfactant which showed that the wide range of antimicrobial activity against bacterial pathogen as well as its antiadhesive properties reduces the adhesion of pathogens into gastric wall membrane. Furthermore, LAB strains have also been reported for production of antioxidants which are ability to scavenge the free radicals such as superoxide anions and hydroxyl radicals. For this sense, this review article is mainly focused on the ecology, biosynthesis, genetics, target sites, and applications of bacteriocins and EPS from LAB strains. Moreover, this review discusses about the production and functions of nutritive essential element folate and iron chelating agent such as siderophores from LAB.
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Affiliation(s)
- Paulraj Kanmani
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Pondicherry, 605014, India
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Xue X, Li J, Wang W, Sztajer H, Wagner-Döbler I. The global impact of the delta subunit RpoE of the RNA polymerase on the proteome of Streptococcus mutans. Microbiology (Reading) 2012; 158:191-206. [DOI: 10.1099/mic.0.047936-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Xiaoli Xue
- Research Group Microbial Communication, Division of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, D-38124 Braunschweig, Germany
| | - Jinshan Li
- Institute of Microbiology, Chinese Academy of Sciences, No. 1 West Beichen Road, Chaoyang District, 100101 Beijing, PR China
- Institute of Bioprocess and Biosystems Engineering, Technical University Hamburg-Harburg, Denickestr. 15, D-21071 Hamburg, Germany
| | - Wei Wang
- Institute of Bioprocess and Biosystems Engineering, Technical University Hamburg-Harburg, Denickestr. 15, D-21071 Hamburg, Germany
| | - Helena Sztajer
- Research Group Microbial Communication, Division of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, D-38124 Braunschweig, Germany
| | - Irene Wagner-Döbler
- Research Group Microbial Communication, Division of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, D-38124 Braunschweig, Germany
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Dimopoulou M, Hazo L, Dols-Lafargue M. Exploration of phenomena contributing to the diversity of Oenococcus oeni exopolysaccharides. Int J Food Microbiol 2011; 153:114-22. [PMID: 22119266 DOI: 10.1016/j.ijfoodmicro.2011.10.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 10/13/2011] [Accepted: 10/29/2011] [Indexed: 11/19/2022]
Abstract
Many food-grade bacteria produce exopolysaccharides (EPS) that may modify the food texture or affect their survival rate during food processing. This is the case of O. oeni, a bacterial species who drives malolactic fermentation in wine. The five strains analyzed in the present study all display both isolated genes dedicated to homopolysaccharide synthesis and gene clusters potentially associated with heteropolysaccharide synthesis. The number of isolated glycosyltransferase gene present and the gene composition of one of the operons change from one strain to the other. The soluble EPS yields and the EPS monomer composition vary depending on the strain and or the medium composition. O. oeni appears as a bacterium able to synthesize both homo and heteropolysaccharides. This unique property has rarely been described. Moreover, the abundance of the genetic determinants associated with EPS metabolism suggests that it is very important for the adaptation of the bacteria to wine.
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Affiliation(s)
- Maria Dimopoulou
- Université de Bordeaux, IPB, ISVV, EA 4602, Unité de recherche OENOLOGIE, INRA USC 1219, 210 chemin de leysotte, 33882 Villenave d'Ornon cedex, France
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28
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Audy J, Labrie S, Roy D, LaPointe G. Sugar source modulates exopolysaccharide biosynthesis in Bifidobacterium longum subsp. longum CRC 002. Microbiology (Reading) 2010; 156:653-664. [DOI: 10.1099/mic.0.033720-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The effect of four sugars (glucose, galactose, lactose and fructose) on exopolysaccharide (EPS) production by Bifidobacterium longum subsp. longum CRC 002 was evaluated. More EPS was produced when CRC 002 was grown on lactose in the absence of pH control, with a production of 1080±120 mg EPS l−1 (P<0.01) after 24 h of incubation. For fructose, galactose and glucose, EPS production was similar, at 512±63, 564±165 and 616±93 mg EPS l−1, respectively. The proposed repeating unit composition of the EPS is 2 galactose to 3 glucose. The effect of sugar and fermentation time on expression of genes involved in sugar nucleotide production (galK, galE1, galE2, galT1, galT2, galU, rmlA, rmlB1 and rmlCD) and the priming glycosyltransferase (wblE) was quantified using real-time reverse transcription PCR. A significantly higher transcription level of wblE (9.29-fold) and the genes involved in the Leloir pathway (galK, 4.10-fold; galT1, 2.78-fold; and galE2, 4.95-fold) during exponential growth was associated with enhanced EPS production on lactose compared to glucose. However, galU expression, linking glucose metabolism with the Leloir pathway, was not correlated with EPS production on different sugars. Genes coding for dTDP-rhamnose biosynthesis were also differentially expressed depending on sugar source and growth phase, although rhamnose was not present in the composition of the EPS. This precursor may be used in cell wall polysaccharide biosynthesis. These results contribute to understanding the changes in gene expression when different sugar substrates are catabolized by B. longum subsp. longum CRC 002.
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Affiliation(s)
- Julie Audy
- Institute for Nutraceuticals and Functional Foods, Université Laval, 2440 Boul. Hochelaga, Québec, QC G1V 0A6, Canada
| | - Steve Labrie
- Institute for Nutraceuticals and Functional Foods, Université Laval, 2440 Boul. Hochelaga, Québec, QC G1V 0A6, Canada
| | - Denis Roy
- Institute for Nutraceuticals and Functional Foods, Université Laval, 2440 Boul. Hochelaga, Québec, QC G1V 0A6, Canada
| | - Gisèle LaPointe
- Institute for Nutraceuticals and Functional Foods, Université Laval, 2440 Boul. Hochelaga, Québec, QC G1V 0A6, Canada
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29
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Production of polysaccharides by submerged mycelial culture of entomopathogenic fungus Cordyceps takaomontana and their apoptotic effects on human neuroblastoma cells. KOREAN J CHEM ENG 2010. [DOI: 10.1007/s11814-009-0179-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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30
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Yang YH, Song E, Park SH, Kim JN, Lee K, Kim E, Kim YG, Kim BG. Loss of phosphomannomutase activity enhances actinorhodin production in Streptomyces coelicolor. Appl Microbiol Biotechnol 2009; 86:1485-92. [PMID: 20024545 DOI: 10.1007/s00253-009-2368-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Revised: 11/11/2009] [Accepted: 11/13/2009] [Indexed: 11/30/2022]
Abstract
Phosphomannomutase (ManB), whose main function is the conversion of mannose-6-phosphate to mannose-1-phosphate, is involved in biosynthesis of GDP-mannose for numerous processes such as synthesis of structural carbohydrates, production of alginates and ascorbic acid, and post-translational modification of proteins in prokaryotes and eukaryotes. ManB isolated from Streptomyces coelicolor was shown to have both phosphomannomutase and phosphoglucomutase activities. Deletion of manB in S. coelicolor caused a dramatic increase in actinorhodin (ACT) production in the low-glucose Difco nutrient (DN) medium, whereas the wild-type strain did not produce ACT on this medium. Experiments involving complementation of the manB deletion showed that increased ACT production in DN media was due to blockage of phosphomannomutase activity rather than phosphoglucomutase activity. This result therefore provides useful information for the design of strategies that enhance antibiotic production through the control of carbon flux.
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Affiliation(s)
- Yung-Hun Yang
- School of Chemical and Biological Engineering, Seoul National University, Seoul, Korea
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31
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Planchon S, Desvaux M, Chafsey I, Chambon C, Leroy S, Hébraud M, Talon R. Comparative subproteome analyses of planktonic and sessile Staphylococcus xylosus C2a: new insight in cell physiology of a coagulase-negative Staphylococcus in biofilm. J Proteome Res 2009; 8:1797-809. [PMID: 19253936 DOI: 10.1021/pr8004056] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Staphylococcus xylosus is a Gram-positive bacterium found on the skin of mammals and frequently isolated from food plants and fermented cheese or meat. To gain further insight in protein determinants involved in biofilm formation by this coagulase-negative Staphylococcus, a comparative proteomic analysis between planktonic and sessile cells was performed. With the use of a protocol previously developed, protein patterns of the cytoplasmic and cell envelope fractions were compared by 2-DE. Following protein identification by MALDI-TOF mass spectrometry and bioinformatic analyses, this study revealed differences in expression levels of 89 distinct proteins with 55 up-expressed and 34 down-expressed proteins in biofilm compared to planktonic cells. Most proteins differentially expressed were related to nitrogen and carbon metabolisms. Besides amino acid biosynthesis and protein translation, protein determinants related to protein secretion were up-expressed in biofilm, suggesting a more active protein trafficking in sessile cells. While up-expression of several enzymes involved in pentose phosphate and glycolytic pathways was observed in biofilm, connections with unexpected metabolic routes were further unravelled. Indeed, this proteomic analysis allowed identifying novel proteins that could be involved in a previously uncovered exopolysaccharide biosynthetic pathway in S. xylosus as well as several enzymes related to polyketide biosynthesis. This findings are particularly relevant considering exopolysaccharide production in S. xylosus is ica-independent contrary to coagulase-negative model strain Staphylococcus epidermidis RP62A.
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Affiliation(s)
- Stella Planchon
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France
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32
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Bauer R, Bekker JP, Wyk NV, du Toit C, Dicks LMT, Kossmann J. Exopolysaccharide production by lactose-hydrolyzing bacteria isolated from traditionally fermented milk. Int J Food Microbiol 2009; 131:260-4. [PMID: 19282044 DOI: 10.1016/j.ijfoodmicro.2009.02.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 02/13/2009] [Accepted: 02/21/2009] [Indexed: 10/21/2022]
Abstract
With increasing consumer demands for safer, healthier and more natural products, bacterially produced exopolysaccharides (EPSs) are becoming a viable option as an additive in designer-type foods. Fresh milk samples from cattle and sheep were collected from informal settlements in South Africa. After a three day incubation period at 25 degrees C, 550 bacterial strains were isolated and evaluated for EPS production from lactose as sole carbon source. Strains producing EPS on lactose were identified to species level with 16S rRNA gene sequencing and encompass 11 Gram-positive and 6 Gram-negative bacteria. EPS production was assigned for the first time to members of the species Staphylococcus hominis and Enterococcus lactis, and also to apparently novel species of the genera Sphingomonas and Acinetobacter. The polymers consisted mainly out of galactose and glucose, while a few isolates also incorporated rhamnose. Isolates produced diverse biopolymers as seen by significant differences in monomer ratios.
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Affiliation(s)
- Rolene Bauer
- Institute for Plant Biotechnology, Genetics Department, Stellenbosch University, Matieland 7602, Stellenbosh, South Africa.
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33
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Robitaille G, Tremblay A, Moineau S, St-Gelais D, Vadeboncoeur C, Britten M. Fat-free yogurt made using a galactose-positive exopolysaccharide-producing recombinant strain of Streptococcus thermophilus. J Dairy Sci 2009; 92:477-82. [DOI: 10.3168/jds.2008-1312] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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34
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Improvement of exo-polysaccharides production and modeling kinetics by Armillaria luteo-virens Sacc. in submerged cultivation. Lebensm Wiss Technol 2008. [DOI: 10.1016/j.lwt.2007.10.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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35
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Characterization of exopolysaccharide (EPS) produced by Weissella hellenica SKkimchi3 isolated from kimchi. J Microbiol 2008; 46:535-41. [DOI: 10.1007/s12275-008-0134-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 07/28/2008] [Indexed: 10/21/2022]
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36
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Hassan A. ADSA Foundation Scholar Award: Possibilities and Challenges of Exopolysaccharide-Producing Lactic Cultures in Dairy Foods. J Dairy Sci 2008; 91:1282-98. [DOI: 10.3168/jds.2007-0558] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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37
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Robitaille G, Moineau S, St-Gelais D, Vadeboncoeur C, Britten M. Galactose metabolism and capsule formation in a recombinant strain of Streptococcus thermophilus with a galactose-fermenting phenotype. J Dairy Sci 2007; 90:4051-7. [PMID: 17699021 DOI: 10.3168/jds.2007-0140] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The capsule-producing, galactose-negative Streptococcus thermophilus MR-1C strain was first transformed with a low-copy plasmid containing a functional galK gene from Streptococcus salivarius to generate a recombinant galactose-fermenting Strep. thermophilus strain named MR-AAC. Then, we compared the functional properties of Strep. thermophilus MR-AAC with those of the parent MR-1C strain when used as starter for fermented products and cheese. In lactose-supplemented laboratory medium, MR-AAC metabolized galactose, but only when the amount of lactose was less than 0.1% (wt/vol). After 7 h of fermentation, the medium was almost depleted of galactose. The parent strain, MR-1C, showed the same pattern, except that the concentration of galactose decreased by only 25% during the same period. It was found that, during milk fermentation and Mozzarella cheese production, the galactose-fermenting phenotype was not expressed by MR-AAC and this strain expelled galactose into the medium at a level similar to the parent MR-1C strain. In milk and in lactose-supplemented medium, capsular exopolysaccharide production occurred mainly during the late exponential phase and the stationary growth phase with similar kinetics between MR-1C and MR-AAC.
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Affiliation(s)
- G Robitaille
- Food Research and Development Centre, Agriculture and Agri-Food Canada, St-Hyacinthe, Quebec, Canada, J2S 8E3.
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38
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Van der Meulen R, Grosu-Tudor S, Mozzi F, Vaningelgem F, Zamfir M, de Valdez GF, De Vuyst L. Screening of lactic acid bacteria isolates from dairy and cereal products for exopolysaccharide production and genes involved. Int J Food Microbiol 2007; 118:250-8. [PMID: 17716765 DOI: 10.1016/j.ijfoodmicro.2007.07.014] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Revised: 05/04/2007] [Accepted: 07/22/2007] [Indexed: 11/16/2022]
Abstract
A total of 174 lactic acid bacteria (LAB) strains isolated from dairy and cereal products were screened for the production of exopolysaccharides (EPS). Therefore, a rapid screening method was developed based on ultrafiltration and gel permeation chromatography. Furthermore, a screening through the polymerase chain reaction (PCR) was performed with primer pairs targeting different genes involved in EPS production. Nine isolates produced a homopolysaccharide of the glucan type, whereas only one strain produced a heteropolysaccharide. The production of a glucan by a strain of Lactococcus lactis and the production of a heteropolysaccharide by a strain of Lactobacillus curvatus are reported for the first time. The PCR screening revealed many positive strains. For three of the ten EPS-producing strains, no corresponding genes could be detected. Furthermore, a lot of strains possessed one or more eps genes but did not produce an EPS. Therefore, a screening on the molecular level should always be accompanied by another screening method that is able to distinguish true EPS producer strains from non-producing ones. Statistical analysis did not reveal any relationship between the type and origin of the strains, the presence or absence of a capsular polysaccharide or EPS, and the presence or absence of eps genes.
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Affiliation(s)
- Roel Van der Meulen
- Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Department of Applied Biological Sciences and Engineering, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
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39
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Morán-Zorzano MT, Viale AM, Muñoz FJ, Alonso-Casajús N, Eydallín GG, Zugasti B, Baroja-Fernández E, Pozueta-Romero J. Escherichia coli AspP activity is enhanced by macromolecular crowding and by both glucose-1,6-bisphosphate and nucleotide-sugars. FEBS Lett 2007; 581:1035-40. [PMID: 17306798 DOI: 10.1016/j.febslet.2007.02.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 01/24/2007] [Accepted: 02/01/2007] [Indexed: 11/25/2022]
Abstract
Escherichia coli ADP-sugar pyrophosphatase (AspP) is a "Nudix" hydrolase that catalyzes the hydrolytic breakdown of ADP-glucose linked to glycogen biosynthesis. Moderate increases of AspP activity in the cell are accompanied by significant reductions of the glycogen content. In vitro analyses showed that AspP activity is strongly enhanced by macromolecular crowding and by both glucose-1,6-bisphosphate and nucleotide-sugars, providing a first set of indicative evidences that AspP is a highly regulated enzyme. To our knowledge, AspP is the sole bacterial enzyme described to date which is activated by both G1,6P(2) and nucleotide-sugars.
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Affiliation(s)
- María Teresa Morán-Zorzano
- Instituto de Agrobiotecnología, Universidad Pública de Navarra/Gobierno de Navarra/Consejo Superior de Investigaciones Científicas, Carretera de Mutilva s/n, 31192 Mutilva Baja, Navarra, Spain
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40
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Svensson M, Lohmeier-Vogel E, Waak E, Svensson U, Rådström P. Altered nucleotide sugar metabolism in Streptococcus thermophilus interferes with nitrogen metabolism. Int J Food Microbiol 2007; 113:195-200. [PMID: 16996629 DOI: 10.1016/j.ijfoodmicro.2006.06.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2005] [Revised: 02/24/2006] [Accepted: 06/13/2006] [Indexed: 11/24/2022]
Abstract
Exopolysaccharide (EPS)-producing Streptococcus thermophilus strains have attracted interest recently, since the EPSs act as natural viscosifiers and texture enhancers of fermented foods. We have previously reported that the low level of EPS production by S. thermophilus LY03 could be improved by altering the activities of enzymes in the central carbon metabolism involved in the nucleotide sugar metabolism. In this study, we observed a reduced growth in milk for the strains with increased UDP-glucose pyrophosphorylase (GalU) activity together with either enhanced phosphoglucomutase activity, and/or enhanced activity of the Leloir enzymes. Rapid growth of these mutants in milk could be restored by the addition of four specific amino acids, i.e. Glu, His, Met, and Val. This amino acid requirement was confirmed in a defined medium. Furthermore, the 31P NMR spectra showed higher levels of the GalU reactants pyrophosphate (PPi) and UDP-glucose in the engineered strain, TMB 6013, compared to the parent strain, LY03. These products plus Glu and the GalU reactant UTP are known to be involved in the nitrogen regulatory system in many bacteria. Thus, these results suggest that the reaction catalyzed by GalU is connected to the nitrogen demand of these engineered strains.
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Affiliation(s)
- M Svensson
- Applied Microbiology, Lund Institute of Technology, Lund University, SE-221 00 Lund, Sweden
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41
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Neves AR, Pool WA, Castro R, Mingote A, Santos F, Kok J, Kuipers OP, Santos H. The α-Phosphoglucomutase of Lactococcus lactis Is Unrelated to the α-d-Phosphohexomutase Superfamily and Is Encoded by the Essential Gene pgmH. J Biol Chem 2006; 281:36864-73. [PMID: 16980299 DOI: 10.1074/jbc.m607044200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha-Phosphoglucomutase (alpha-PGM) plays an important role in carbohydrate metabolism by catalyzing the reversible conversion of alpha-glucose 1-phosphate to glucose 6-phosphate. Isolation of alpha-PGM activity from cell extracts of Lactococcus lactis strain MG1363 led to the conclusion that this activity is encoded by yfgH, herein renamed pgmH. Its gene product has no sequence homology to proteins in the alpha-d-phosphohexomutase superfamily and is instead related to the eukaryotic phosphomannomutases within the haloacid dehalogenase superfamily. In contrast to known bacterial alpha-PGMs, this 28-kDa enzyme is highly specific for alpha-glucose 1-phosphate and glucose 6-phosphate and showed no activity for mannose phosphate. To elucidate the function of pgmH, the metabolism of glucose and galactose was characterized in mutants overproducing or with a deficiency of alpha-PGM activity. Overproduction of alpha-PGM led to increased glycolytic flux and growth rate on galactose. Despite several attempts, we failed to obtain a deletion mutant of pgmH. The essentiality of this gene was proven by using a conditional knock-out strain in which a native copy of the gene was provided in trans under the control of the nisin promoter. Growth of this strain was severely impaired when alpha-PGM activity was below the control level. We show that the novel L. lactis alpha-PGM is the only enzyme that mediates the interconversion of alpha-glucose 1-phosphate to glucose 6-phosphate and is essential for growth.
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Affiliation(s)
- Ana R Neves
- Instituto de Tecnologia Química e Biológica and Instituto de Biologia Experimental e Tecnológica, Universidade Nova de Lisboa, Rua da Quinta Grande, 6, Apartado 127, 2780-156 Oeiras, Portugal
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42
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Cho EJ, Oh JY, Chang HY, Yun JW. Production of exopolysaccharides by submerged mycelial culture of a mushroom Tremella fuciformis. J Biotechnol 2006; 127:129-40. [PMID: 16872706 DOI: 10.1016/j.jbiotec.2006.06.013] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Revised: 05/19/2006] [Accepted: 06/22/2006] [Indexed: 11/30/2022]
Abstract
The optimization of submerged culture conditions for mycelial growth and exopolysaccharide (EPS) production in an edible mushroom Tremella fuciformis was studied in shake flasks and bioreactors. The temperature of 28 degrees C and pH 8 in the beginning of fermentation in agitated flasks was the most efficient condition to obtain maximum mycelial biomass and EPS. The optimal medium constituents were as follows (gL(-1)): glucose 20, tryptone 2, KH(2)PO(4) 0.46, K(2)HPO(4) 1 and MgSO(4).7H(2)O 0.5. The fungus was cultivated under various agitation and aeration conditions in a 5L stirred-tank bioreactor. The maximum cell mass and EPS production were obtained at a relatively high agitation speed of 200 rpm and at an aeration rate of 2 vvm. The flow behavior of the fermentation broth was Newtonian and the maximum apparent viscosity (35 cP) was observed at a highly aerated condition (2 vvm). The EPS productivity in an airlift reactor was higher than that in the stirred-tank reactor. The morphological study revealed that the fungus grows in mainly three different yeast-like forms: ovoid, elongated, and double yeast forms. The high population of the elongated yeast has a very close relationship to high EPS production. The EPS were protein-bound polysaccharides consisted of mainly mannose, xylose, and fucose. The molecular weights of EPS were determined to be (1.3-1.5)x10(6).
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Affiliation(s)
- Eun Jae Cho
- Department of Biotechnology, Daegu University, Kyungsan, Kyungbuk 712-714, Republic of Korea
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43
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Blanch M, Legaz ME, Vicente C. Purification and properties of an unusual UDP-glucose dehydrogenase, NADPH-dependent, from Xanthomonas albilineans. Microbiol Res 2006; 163:362-71. [PMID: 17010583 DOI: 10.1016/j.micres.2006.07.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2006] [Revised: 07/12/2006] [Accepted: 07/18/2006] [Indexed: 11/28/2022]
Abstract
Xanthomonas albilineans produces a UDP-glucose dehydrogenase growing on sucrose. The enzyme oxidizes UDP-glucose to UDP-glucuronic acid by using molecular oxygen and NADPH. Kinetics of enzymatic oxydation of NADPH is linearly dependent on the amount of oxygen supplied. The enzyme has been purified at homogeneity. The value of pI of the purified enzyme is 8.98 and its molecular mass has been estimated as about 14 kDa. The enzyme shows a michaelian kinetics for UDP-glucose concentrations. The value of K(m) for UDP-glucose is 0.87 mM and 0.26 mM for NADPH, although the enzyme has three different sites to interact with NADPH. The enzyme is inhibited by UDP-glucose concentrations higher than 1.3 mM. N-Terminal sequence has been determined as IQPYNH.
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Affiliation(s)
- María Blanch
- Laboratory of Plant Physiology, Faculty of Biology, Complutense University, Madrid, Spain
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44
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Arena S, D'Ambrosio C, Renzone G, Rullo R, Ledda L, Vitale F, Maglione G, Varcamonti M, Ferrara L, Scaloni A. A study ofStreptococcus thermophilus proteome by integrated analytical procedures and differential expression investigations. Proteomics 2006; 6:181-92. [PMID: 16281183 DOI: 10.1002/pmic.200402109] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Streptococcus thermophilus is a Gram-positive bacterium belonging to the group of lactic acid bacteria, among which several genera play an essential role in manufacture of food products. Recently, a genomic consortium sequenced and annotated its entire genome, which has been demonstrated to contain 1900 coding sequences. In this study, we have revealed the expression products of almost 200 different genes using a proteomic strategy combining 2-DE plus MALDI-TOF PMF and differential 1-DE plus muLC-ESI-IT-MS/MS. Thus, a number of cellular pathways related to important physiological processes were described at the proteomic level. Almost 50 genes were related to multiple electrophoretic species, whose heterogeneity was mainly due to variability in pI values. A 2-DE reference map obtained for lactose-grown cells was compared with those obtained after heat, cold, acid, oxidative and starvation stresses. Protein up/down-regulation measurements demonstrated that adaptation to different environmental challenges may involve the contribution of unique as well as combined physiological mechanisms. Common regulatory sites in the promoter region of genes whose expression was induced after stress were identified. These results provide a better comprehension of biochemical processes related to stress resistance in S. thermophilus, allowing defining the molecular bases of adaptative responses or markers for the identification of strains with potential industrial applications.
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Affiliation(s)
- Simona Arena
- Proteomics & Mass Spectrometry Laboratory, I.S.P.A.A.M., National Research Council, via Argine 1085, 80147 Naples, Italy
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Buchanan JT, Stannard JA, Lauth X, Ostland VE, Powell HC, Westerman ME, Nizet V. Streptococcus iniae phosphoglucomutase is a virulence factor and a target for vaccine development. Infect Immun 2005; 73:6935-44. [PMID: 16177373 PMCID: PMC1230984 DOI: 10.1128/iai.73.10.6935-6944.2005] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus iniae represents a major health and economic problem in fish species worldwide. Random Tn917 mutagenesis and high-throughput screening in a hybrid striped bass (HSB) model of meningoencephalitis identified attenuated S. iniae mutants. The Tn917 insertion in one mutant disrupted an S. iniae homologue of a phosphoglucomutase (pgm) gene. Electron microscopy revealed a decrease in capsule thickness and cell wall rigidity, with DeltaPGM mutant cells reaching sizes approximately 3-fold larger than those of the wild type (WT). The DeltaPGM mutant was cleared more rapidly in HSB blood and was more sensitive to killing by cationic antimicrobial peptides including moronecidin from HSB. In vivo, the DeltaPGM mutant was severely attenuated in HSB, as intraperitoneal challenge with 1,000 times the WT lethal dose produced only 2.5% mortality. Reintroduction of an intact copy of the S. iniae pgm gene on a plasmid vector restored antimicrobial peptide resistance and virulence to the DeltaPGM mutant. In analysis of the aborted infectious process, we found that DeltaPGM mutant organisms initially disseminated to the blood, brain, and spleen but were eliminated by 24 h without end organ damage. Ninety to 100% of fish injected with the DeltaPGM mutant and later challenged with a lethal dose of WT S. iniae survived. We conclude that the pgm gene is required for virulence in S. iniae, playing a role in normal cell wall morphology, surface capsule expression, and resistance to innate immune clearance mechanisms. An S. iniae DeltaPGM mutant is able to stimulate a protective immune response and may have value as a live attenuated vaccine for aquaculture.
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Affiliation(s)
- John T Buchanan
- Department of Pediatrics, University of California, San Diego, School of Medicine, La Jolla, 92093, USA.
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Hols P, Hancy F, Fontaine L, Grossiord B, Prozzi D, Leblond-Bourget N, Decaris B, Bolotin A, Delorme C, Dusko Ehrlich S, Guédon E, Monnet V, Renault P, Kleerebezem M. New insights in the molecular biology and physiology ofStreptococcus thermophilusrevealed by comparative genomics. FEMS Microbiol Rev 2005. [DOI: 10.1016/j.fmrre.2005.04.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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de Vin F, Rådström P, Herman L, De Vuyst L. Molecular and biochemical analysis of the galactose phenotype of dairy Streptococcus thermophilus strains reveals four different fermentation profiles. Appl Environ Microbiol 2005; 71:3659-67. [PMID: 16000774 PMCID: PMC1168995 DOI: 10.1128/aem.71.7.3659-3667.2005] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2004] [Accepted: 02/03/2005] [Indexed: 11/20/2022] Open
Abstract
Lactose-limited fermentations of 49 dairy Streptococcus thermophilus strains revealed four distinct fermentation profiles with respect to galactose consumption after lactose depletion. All the strains excreted galactose into the medium during growth on lactose, except for strain IMDOST40, which also displayed extremely high galactokinase (GalK) activity. Among this strain collection eight galactose-positive phenotypes sensu stricto were found and their fermentation characteristics and Leloir enzyme activities were measured. As the gal promoter seems to play an important role in the galactose phenotype, the galR-galK intergenic region was sequenced for all strains yielding eight different nucleotide sequences (NS1 to NS8). The gal promoter played an important role in the Gal-positive phenotype but did not determine it exclusively. Although GalT and GalE activities were detected for all Gal-positive strains, GalK activity could only be detected for two out of eight Gal-positive strains. This finding suggests that the other six S. thermophilus strains metabolize galactose via an alternative route. For each type of fermentation profile obtained, a representative strain was chosen and four complete Leloir gene clusters were sequenced. It turned out that Gal-positive strains contained more amino acid differences within their gal genes than Gal-negative strains. Finally, the biodiversity regarding lactose-galactose utilization among the different S. thermophilus strains used in this study was shown by RAPD-PCR. Five Gal-positive strains that contain nucleotide sequence NS2 in their galR-galK intergenic region were closely related.
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Affiliation(s)
- Filip de Vin
- Research Group of Industrial Microbiology, Fermentation Technology and Downstream Processing (IMDO), Department of Applied Biological Sciences, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussels, Belgium
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Vaningelgem F, Zamfir M, Adriany T, De Vuyst L. Fermentation conditions affecting the bacterial growth and exopolysaccharide production by Streptococcus thermophilus ST 111 in milk-based medium. J Appl Microbiol 2005; 97:1257-73. [PMID: 15546417 DOI: 10.1111/j.1365-2672.2004.02418.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To study the effect of different fermentation conditions and to model the effect of temperature and pH on different biokinetic parameters of bacterial growth and exopolysaccharides (EPS) production of Streptococcus thermophilus ST 111 in milk-based medium. METHODS AND RESULTS The influence of temperature and pH was studied through fermentation and modelling. Fermentations under non-pH controlled conditions with S. thermophilus ST 111 indicated that the EPS production was low in milk medium, even if additional nitrogen sources were supplemented. Under pH-controlled conditions, addition of whey protein hydrolysate to the milk medium resulted in a fivefold increase of the EPS production. This medium did not contain polysaccharides interfering with EPS isolation. Primary and secondary modelling of different fermentations revealed an optimum temperature and pH of 40 degrees C and constant pH 6.2, respectively, for growth in milk medium supplemented with whey protein hydrolysate. Maximum EPS production was observed in the range of 32-42 degrees C and constant pH 5.5-6.6. Whereas growth and maximum EPS production were clearly influenced by temperature and pH, the specific EPS production was only affected by stress conditions (T = 49 degrees C). CONCLUSIONS Addition of whey protein hydrolysate to milk medium resulted in an increased growth and EPS production of S. thermophilus ST 111 under pH-controlled conditions. A modelling approach allowed studying the influence of temperature and pH on the kinetics of both growth and EPS production. SIGNIFICANCE AND IMPACT OF THE STUDY The use of an appropriate milk-based medium and a combined model of temperature and pH can be of practical importance for the production of yoghurt or other fermented milks as well as for process optimization of the large-scale production of starter strains to be used for their EPS production.
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Affiliation(s)
- F Vaningelgem
- Department of Applied Biological Sciences, Research Group of Industrial Microbiology, Fermentation Technology and Downstream Processing, Vrije Universiteit Brussel, Brussels, Belgium
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Lazarevic V, Soldo B, Médico N, Pooley H, Bron S, Karamata D. Bacillus subtilis alpha-phosphoglucomutase is required for normal cell morphology and biofilm formation. Appl Environ Microbiol 2005; 71:39-45. [PMID: 15640167 PMCID: PMC544238 DOI: 10.1128/aem.71.1.39-45.2005] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mutations designated gtaC and gtaE that affect alpha-phosphoglucomutase activity required for interconversion of glucose 6-phosphate and alpha-glucose 1-phosphate were mapped to the Bacillus subtilis pgcA (yhxB) gene. Backcrossing of the two mutations into the 168 reference strain was accompanied by impaired alpha-phosphoglucomutase activity in the soluble cell extract fraction, altered colony and cell morphology, and resistance to phages phi29 and rho11. Altered cell morphology, reversible by additional magnesium ions, may be correlated with a deficiency in the membrane glycolipid. The deficiency in biofilm formation in gtaC and gtaE mutants may be attributed to an inability to synthesize UDP-glucose, an important intermediate in a number of cell envelope biosynthetic processes.
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Affiliation(s)
- Vladimir Lazarevic
- Département de Microbiologie Fondamentale, Batiment de Biologie, Faculté de Biologie et de Médecine, Université de Lausanne, CH-1015 Lausanne, Switzerland.
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Torino MI, Mozzi F, Font de Valdez G. Exopolysaccharide biosynthesis by Lactobacillus helveticus ATCC 15807. Appl Microbiol Biotechnol 2005; 68:259-65. [PMID: 15660218 DOI: 10.1007/s00253-004-1865-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Revised: 11/11/2004] [Accepted: 12/03/2004] [Indexed: 10/25/2022]
Abstract
Exopolysaccharide (EPS) production and the activities of the enzymes involved in sugar nucleotide biosynthesis in Lactobacillus helveticus ATCC 15807 under controlled pH conditions were investigated. Batch fermentations using lactose as energy source showed higher EPS synthesis by L. helveticus ATCC 15807 at pH 4.5 with respect to pH 6.2, the enzyme alpha-phosphoglucomutase (alpha-PGM) being correlated with both total and specific EPS production. When glucose was used as carbon source instead of lactose, the lower EPS synthesis obtained was linked to a decrease in alpha-PGM and galactose 1-phosphate-uridyltransferase (GalT) activities, the reduction of the latter being more pronounced. Higher EPS production by L. helveticus ATCC 15807 at the acidic constant pH of 4.5 requires that both alpha-PGM and GalT activities are high. These enzymes are needed to synthesize UDP-glucose and UDP-galactose for supplying the corresponding monomers for EPS biosynthesis. Although differences are observed in EPS production by this strain regarding the energy source (lactose or glucose), the monomeric composition of the polymers produced is independent of the carbohydrate used. The obtained results contribute to a better understanding of the physiological factors that affect EPS biosynthesis by lactobacilli, which could help in the correct handling of the fermentation parameters within the fermented dairy industry.
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Affiliation(s)
- M I Torino
- Centro de Referencia para Lactobacilos (CERELA-CONICET), Chacabuco 145, San Miguel de Tucumán, 4000 Tucumán, Argentina
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