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Reid A, Erickson KM, Hazel JM, Lukose V, Troutman JM. Chemoenzymatic Preparation of a Campylobacter jejuni Lipid-Linked Heptasaccharide on an Azide-Linked Polyisoprenoid. ACS OMEGA 2023; 8:15790-15798. [PMID: 37151508 PMCID: PMC10157688 DOI: 10.1021/acsomega.3c01657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 04/13/2023] [Indexed: 05/09/2023]
Abstract
Complex poly- and oligosaccharides on the surface of bacteria provide a unique fingerprint to different strains of pathogenic and symbiotic microbes that could be exploited for therapeutics or sensors selective for specific glycans. To discover reagents that can selectively interact with specific bacterial glycans, a system for both the chemoenzymatic preparation and immobilization of these materials would be ideal. Bacterial glycans are typically synthesized in nature on the C55 polyisoprenoid bactoprenyl (or undecaprenyl) phosphate. However, this long-chain isoprenoid can be difficult to work with in vitro. Here, we describe the addition of a chemically functional benzylazide tag to polyisoprenoids. We have found that both the organic-soluble and water-soluble benzylazide isoprenoid can serve as a substrate for the well-characterized system responsible for Campylobacter jejuni N-linked heptasaccharide assembly. Using the organic-soluble analogue, we demonstrate the use of an N-acetyl-glucosamine epimerase that can be used to lower the cost of glycan assembly, and using the water-soluble analogue, we demonstrate the immobilization of the C. jejuni heptasaccharide on magnetic beads. These conjugated beads are then shown to interact with soybean agglutinin, a lectin known to interact with N-acetyl-galactosamine in the C. jejuni heptasaccharide. The methods provided could be used for a wide variety of applications including the discovery of new glycan-interacting partners.
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Affiliation(s)
- Amanda
J. Reid
- Nanoscale
Science Program, University of North Carolina
at Charlotte, 9201 University City Blvd., Charlotte, North Carolina 28223, United States
| | - Katelyn M. Erickson
- Nanoscale
Science Program, University of North Carolina
at Charlotte, 9201 University City Blvd., Charlotte, North Carolina 28223, United States
| | - Joseph M. Hazel
- Department
of Chemistry, University of North Carolina
at Charlotte, 9201 University
City Blvd., Charlotte, North
Carolina 28223, United States
- Department
of Chemistry, The Ohio State University, 281 W Lane Avenue, Columbus, Ohio 43210, United States
| | - Vinita Lukose
- Departments
of Chemistry and Biology, Massachusetts
Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Jerry M. Troutman
- Nanoscale
Science Program, University of North Carolina
at Charlotte, 9201 University City Blvd., Charlotte, North Carolina 28223, United States
- Department
of Chemistry, University of North Carolina
at Charlotte, 9201 University
City Blvd., Charlotte, North
Carolina 28223, United States
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2
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Chen Q, Wang M, Han M, Xu L, Zhang H. Molecular basis of Klebsiella pneumoniae colonization in host. Microb Pathog 2023; 177:106026. [PMID: 36773942 DOI: 10.1016/j.micpath.2023.106026] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 02/03/2023] [Accepted: 02/05/2023] [Indexed: 02/12/2023]
Abstract
Klebsiella pneumoniae (K. pneumoniae) is a common cause of nosocomial infection, which causing disseminated infections such as cystitis, pneumonia and sepsis. K. pneumoniae is intrinsic resistant to penicillin, and members of the population usually have acquired resistance to a variety of antibiotics, which makes it a major threat to clinical and public health. Bacteria can colonize on or within the hosts, accompanied by growth and reproduction of the organisms, but no clinical symptoms are presented. As the "first step" of bacterial infection, colonization in the hosts is of great importance. Colonization of bacteria can last from days to years, with resolution influenced by immune response to the organism, competition at the site from other organisms and, sometimes, use of antimicrobials. Colonized pathogenic bacteria cause healthcare-associated infections at times of reduced host immunity, which is an important cause of clinical occurrence of postoperative complications and increased mortality in ICU patients. Though, K. pneumoniae is one of the most common conditional pathogens of hospital-acquired infections, the mechanisms of K. pneumoniae colonization in humans are not completely clear. In this review, we made a brief summary of the molecular basis of K. pneumoniae colonization in the upper respiratory tract and intestinal niche, and provided new insights for understanding the pathogenesis of K. pneumoniae.
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Affiliation(s)
- Qi Chen
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Min Wang
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Mingxiao Han
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Leyi Xu
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Haifang Zhang
- Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, China.
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3
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Ağagündüz D, Yılmaz B, Koçak T, Altıntaş Başar HB, Rocha JM, Özoğul F. Novel Candidate Microorganisms for Fermentation Technology: From Potential Benefits to Safety Issues. Foods 2022; 11:foods11193074. [PMID: 36230150 PMCID: PMC9564171 DOI: 10.3390/foods11193074] [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: 08/31/2022] [Revised: 09/22/2022] [Accepted: 09/29/2022] [Indexed: 11/16/2022] Open
Abstract
Fermentation is one of the oldest known production processes and the most technologically valuable in terms of the food industry. In recent years, increasing nutrition and health awareness has also changed what is expected from fermentation technology, and the production of healthier foods has started to come a little more forward rather than increasing the shelf life and organoleptic properties of foods. Therefore, in addition to traditional microorganisms, a new generation of (novel) microorganisms has been discovered and research has shifted to this point. Novel microorganisms are known as either newly isolated genera and species from natural sources or bacterial strains derived from existing bacteria. Although novel microorganisms are mostly studied for their use in novel food production in terms of gut-microbiota modulation, recent innovative food research highlights their fermentative effects and usability, especially in food modifications. Herein, Clostridium butyricum, Bacteroides xylanisolvens, Akkermansia muciniphila, Mycobacterium setense manresensis, and Fructophilic lactic acid bacteria (FLAB) can play key roles in future candidate microorganisms for fermentation technology in foods. However, there is also some confusion about the safety issues related to the use of these novel microorganisms. This review paper focuses on certain novel candidate microorganisms for fermentation technology with a deep view of their functions, benefits, and safety issues.
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Affiliation(s)
- Duygu Ağagündüz
- Department of Nutrition and Dietetics, Gazi University, Emek, Ankara 06490, Turkey
| | - Birsen Yılmaz
- Department of Nutrition and Dietetics, Cukurova University, Sarıcam, Adana 01380, Turkey
| | - Tevfik Koçak
- Department of Nutrition and Dietetics, Gazi University, Emek, Ankara 06490, Turkey
| | | | - João Miguel Rocha
- Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, 4050-345 Porto, Portugal
- Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, 4050-345 Porto, Portugal
- Correspondence:
| | - Fatih Özoğul
- Department of Seafood Processing Technology, Faculty of Fisheries, Cukurova University, Balcali, Adana 01330, Turkey
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4
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Erturk-Hasdemir D, Kasper DL. Finding a needle in a haystack: Bacteroides fragilis polysaccharide A as the archetypical symbiosis factor. Ann N Y Acad Sci 2018. [PMID: 29528123 DOI: 10.1111/nyas.13660] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Starting from birth, all animals develop a symbiotic relationship with their resident microorganisms that benefits both the microbe and the host. Recent advances in technology have substantially improved our ability to direct research toward the identification of important microbial species that affect host physiology. The identification of specific commensal molecules from these microbes and their mechanisms of action is still in its early stages. Polysaccharide A (PSA) of Bacteroides fragilis is the archetypical example of a commensal molecule that can modulate the host immune system in health and disease. This zwitterionic polysaccharide has a critical impact on the development of the mammalian immune system and also on the stimulation of interleukin 10-producing CD4+ T cells; consequently, PSA confers benefits to the host with regard to experimental autoimmune, inflammatory, and infectious diseases. In this review, we summarize the current understanding of the immunomodulatory effects of B. fragilis PSA and discuss these effects as a novel immunological paradigm. In particular, we discuss recent advances in our understanding of the unique functional mechanisms of this molecule and its therapeutic potential, and we review the recent literature in the field of microbiome research aimed at discovering new commensal products and their immunomodulatory potential.
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Affiliation(s)
- Deniz Erturk-Hasdemir
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts
| | - Dennis L Kasper
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts
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5
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Escribano BM, Medina-Fernández FJ, Aguilar-Luque M, Agüera E, Feijoo M, Garcia-Maceira FI, Lillo R, Vieyra-Reyes P, Giraldo AI, Luque E, Drucker-Colín R, Túnez I. Lipopolysaccharide Binding Protein and Oxidative Stress in a Multiple Sclerosis Model. Neurotherapeutics 2017; 14:199-211. [PMID: 27718209 PMCID: PMC5233624 DOI: 10.1007/s13311-016-0480-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Recent findings in experimental autoimmune encephalomyelitis (EAE) suggest that altering certain bacterial populations present in the gut may lead to a proinflammatory condition, that could result in the development of multiple sclerosis (MS). Also, Reactive Oxygen Species seem to be involved in the course of MS. In this study, it has been aimed to relate all these variables starting from an analysis of the lipopolysaccharide (LPS) and LPS-binding protein (LBP) with the determination of parameters related to oxidative stress in the blood, brain and spinal cord. For this purpose, samples obtained from EAE rats and relapsing-remitting (RRMS) MS patients were used. In addition, EAE rats were treated with Natalizumab, N-acetyl-cysteine and dimethyl fumarate. Natalizumab was also employed in RRMS. The results of this study revealed an improvement in the clinical symptoms of the EAE and MS with the treatments, as well as a reduction in the oxidative stress parameters and in LBP. Correlations between the clinical variables of the disease, i.e. oxidative damage and LBP, were established. Although the conclusions of this research are indeed relevant, further investigation would be necessary to establish the intrinsic mechanisms of the MS-oxidative stress-microbiota relationship.
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Affiliation(s)
- Begoña M Escribano
- Departamento de Biologia Celular, Fisiologia e Inmunologia, Facultad de Veterinaria, Universidad de Cordoba, Cordoba, Spain
- Instituto Maimonides de Investigacion Biomedica de Cordoba (IMIBIC), Cordoba, Spain
| | - Francisco J Medina-Fernández
- Instituto Maimonides de Investigacion Biomedica de Cordoba (IMIBIC), Cordoba, Spain
- Departamento de Bioquimica y Biologia Molecular, Facultad de Medicina, Universidad de Cordoba, Cordoba, Spain
| | - Macarena Aguilar-Luque
- Instituto Maimonides de Investigacion Biomedica de Cordoba (IMIBIC), Cordoba, Spain
- Departamento de Bioquimica y Biologia Molecular, Facultad de Medicina, Universidad de Cordoba, Cordoba, Spain
| | - Eduardo Agüera
- Instituto Maimonides de Investigacion Biomedica de Cordoba (IMIBIC), Cordoba, Spain
- Servicio de Neurología, Hospital Universitario Reina Sofía de Cordoba, Cordoba, Spain
| | - Montserrat Feijoo
- Instituto Maimonides de Investigacion Biomedica de Cordoba (IMIBIC), Cordoba, Spain
- Departamento de Bioquimica y Biologia Molecular, Facultad de Medicina, Universidad de Cordoba, Cordoba, Spain
| | | | - Rafael Lillo
- Instituto Maimonides de Investigacion Biomedica de Cordoba (IMIBIC), Cordoba, Spain
- Departamento de Ciencias Sociosanitarias y Radiologia y Medicina Fisica, Seccion de Psiquiatria, Facultad de Medicina, Universidad de Cordoba, Cordoba, Spain
| | - Patricia Vieyra-Reyes
- Departamento Neurofisiología de la Conducta, Facultad de Medicina, Universidad Autonoma del Estado de México, Toluca, Estado de Mexico, Mexico
| | - Ana I Giraldo
- Instituto Maimonides de Investigacion Biomedica de Cordoba (IMIBIC), Cordoba, Spain
- Departamento de Bioquimica y Biologia Molecular, Facultad de Medicina, Universidad de Cordoba, Cordoba, Spain
| | - Evelio Luque
- Instituto Maimonides de Investigacion Biomedica de Cordoba (IMIBIC), Cordoba, Spain
- Departamento de Ciencias Morfologicas, Seccion Histologia, Facultad de Medicina, Universidad de Cordoba, Cordoba, Spain
| | - René Drucker-Colín
- Departamento de Neuropatologia Molecular, Instituto de Fisiologia Celular, Universidad Nacional Autonoma de Mexico (UNAM), Ciudad de Mexico, D.F., Mexico
| | - Isaac Túnez
- Instituto Maimonides de Investigacion Biomedica de Cordoba (IMIBIC), Cordoba, Spain.
- Departamento de Bioquimica y Biologia Molecular, Facultad de Medicina, Universidad de Cordoba, Cordoba, Spain.
- Red Tematica de Investigacion Cooperativa en Envejecimiento y Fragilidad (RETICEF), Cordoba, Spain.
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6
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Zhang W, Mu H, Dong D, Wang D, Zhang A, Duan J. Alteration in immune responses toward N-deacetylation of hyaluronic acid. Glycobiology 2014; 24:1334-42. [DOI: 10.1093/glycob/cwu079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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7
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Cress BF, Englaender JA, He W, Kasper D, Linhardt RJ, Koffas MAG. Masquerading microbial pathogens: capsular polysaccharides mimic host-tissue molecules. FEMS Microbiol Rev 2014; 38:660-97. [PMID: 24372337 PMCID: PMC4120193 DOI: 10.1111/1574-6976.12056] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 10/16/2013] [Accepted: 12/19/2013] [Indexed: 11/27/2022] Open
Abstract
The increasing prevalence of antibiotic-resistant bacteria portends an impending postantibiotic age, characterized by diminishing efficacy of common antibiotics and routine application of multifaceted, complementary therapeutic approaches to treat bacterial infections, particularly multidrug-resistant organisms. The first line of defense for most bacterial pathogens consists of a physical and immunologic barrier known as the capsule, commonly composed of a viscous layer of carbohydrates that are covalently bound to the cell wall in Gram-positive bacteria or often to lipids of the outer membrane in many Gram-negative bacteria. Bacterial capsular polysaccharides are a diverse class of high molecular weight polysaccharides contributing to virulence of many human pathogens in the gut, respiratory tree, urinary tract, and other host tissues, by hiding cell surface components that might otherwise elicit host immune response. This review highlights capsular polysaccharides that are structurally identical or similar to polysaccharides found in mammalian tissues, including polysialic acid and glycosaminoglycan capsules hyaluronan, heparosan, and chondroitin. Such nonimmunogenic coatings render pathogens insensitive to certain immune responses, effectively increasing residence time in host tissues and enabling pathologically relevant population densities to be reached. Biosynthetic pathways and capsular involvement in immune system evasion are described, providing a basis for potential therapies aimed at supplementing or replacing antibiotic treatment.
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Affiliation(s)
- Brady F Cress
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
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8
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Abstract
The mammalian intestine must manage to contain 100 trillion intestinal bacteria without inducing inappropriate immune responses to these microorganisms. The effects of the immune system on intestinal microorganisms are numerous and well-characterized, and recent research has determined that the microbiota influences the intestinal immune system as well. In this review, we first discuss the intestinal immune system and its role in containing and maintaining tolerance to commensal organisms. We next introduce a category of immune cells, the innate lymphoid cells, and describe their classification and function in intestinal immunology. Finally, we discuss the effects of the intestinal microbiota on innate lymphoid cells.
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9
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Dasgupta S, Kasper DL. Relevance of commensal microbiota in the treatment and prevention of inflammatory bowel disease. Inflamm Bowel Dis 2013; 19:2478-89. [PMID: 23846489 DOI: 10.1097/mib.0b013e318297d884] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Commensal microbiota that reside primarily in the gut of mammals influence the hosts' health to a great extent. Shaping of host immunity locally, a vital component of this influence, can have pro-inflammatory, anti-inflammatory, or neutral outcomes, presumably depending on the composition of the microbiota in an individual and type of molecules expressed in the individual members of the microbiota. Thus, these microbial species can be thought of as a reservoir of molecules that can be used to improve or worsen the condition of patients suffering from immunity or inflammation-driven pathologies like inflammatory bowel disease. In the current review, we elaborate, based on the literature available from murine models of disease and clinical case studies, the need to identify individual members of commensal microbiota that can precipitate or resolve inflammatory bowel disease. Therapeutic approaches could entail enrichment of members of microbiota (or molecules from these microbes), which induces expansion or enhancement of function of regulatory T cells or tolerogenic dendritic cells and reduce members that cause inflammation either directly or indirectly by influencing metabolic and other host molecules. Efficiency of bacteria-driven therapy would potentially be enhanced as we refine our approaches from the use of complete feces as done in fecal transplantation to utilization of microbiota-derived molecules as exemplified by the capsular polysaccharide A from the human gut commensal Bacteroides fragilis. We also highlight the advantages and disadvantages of each approach, defining a natural alternative to the current chemical-based immunosuppressive regimen for patients with inflammatory bowel disease.
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Affiliation(s)
- Suryasarathi Dasgupta
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts
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10
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Shapira I, Sultan K, Lee A, Taioli E. Evolving concepts: how diet and the intestinal microbiome act as modulators of breast malignancy. ISRN ONCOLOGY 2013; 2013:693920. [PMID: 24187630 PMCID: PMC3800670 DOI: 10.1155/2013/693920] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 08/25/2013] [Indexed: 02/07/2023]
Abstract
The intestinal microbiome plays an important role in human physiology. Next-generation sequencing technologies, knockout and gnotobiotic mouse models, fecal transplant data and epidemiologic studies have accelerated our understanding of microbiome abnormalities seen in immune diseases and malignancies. Dysbiosis is the disturbed microbiome ecology secondary to external pressures such as host diseases, medications, diet and genetic conditions often leading to abnormalities of the host immune system. Specifically dysbiosis has been shown to lower circulating lymphocytes, and increase neutrophil to lymphocyte ratio, a finding which has been associated with a decreased survival in women with breast cancers. Dysbiosis also plays a role in the recycling of estrogens via the entero-hepatic circulation, increasing estrogenic potency in the host, which is another leading cause of breast malignancy. Non-modifiable factors such as age and genetic mutations disrupt the microbiome, but modifiable factors such as diet may also lead to profound disruptions as well. A better understanding of dietary factors and how they disrupt the microbiome may lead to beneficial nutritional interventions for breast cancer patients.
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Affiliation(s)
- Iuliana Shapira
- Monter Cancer Center, Don Monti Division of Oncology and Division of Hematology, Hofstra North Shore Long Island Jewish School of Medicine, 450 Lakeville Road, Lake Success, NY 11042, USA
| | - Keith Sultan
- Hofstra North Shore Long Island Jewish School of Medicine, Division of Gastroenterology, Hepatology and Nutrition, North Shore University Hospital, 300 Community Drive, Manhasset, NY 11030, USA
| | - Annette Lee
- Feinstein Institute for Medical Research, Robert S. Boas Center for Genomics and Human Genetics and Elmezzi Graduate School of Molecular Medicine, Hofstra North Shore Long Island Jewish School of Medicine, 350 Community Drive, Manhasset, NY 11030, USA
| | - Emanuela Taioli
- Population Health-Hofstra North Shore-LIJ School of Medicine and North Shore/LIJ Health System, 175 Community Drive, Room 203, Great Neck, NY 11021, USA
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11
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Preliminary safety evaluation of a new Bacteroides xylanisolvens isolate. Appl Environ Microbiol 2011; 78:528-35. [PMID: 22101046 DOI: 10.1128/aem.06641-11] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Besides conferring some health benefit to the host, a bacterial strain must present an unambiguous safety status to be considered a probiotic. We here present the preliminary safety evaluation of a new Bacteroides xylanisolvens strain (DSM 23964) isolated from human feces. First results suggest that it may be able to provide probiotic health benefits. Its identity was confirmed by biochemical analysis, by sequencing of its 16S rRNA genes, and by DNA-DNA hybridization. Virulence determinants known to occur in the genus Bacteroides, such the bft enterotoxin and other enzymatic activities involved in the degradation of the extracellular matrix and the capsular polysaccharide PS A, were absent in this strain. The investigation of the antibiotic susceptibility indicated that strain DSM 23964 was sensitive to metronidazole, meropenem agents, and clindamycin. Resistance to penicillin and ampicillin was identified to be conferred by the β-lactamase cepA gene and could therefore be restored by adding β-lactamase inhibitors. The localization of the cepA gene in the genome of strain DSM 23964 and the absence of detectable plasmids further suggest that a transfer of β-lactamase activity or the acquisition of other antibiotic resistances are highly improbable. Taken together, the presented data indicate that the strain B. xylanisolvens DSM 23964 has no virulence potential. Since it also resists the action of gastric enzymes and low-pH conditions, this strain is an interesting candidate for further investigation of its safety and potential health-promoting properties.
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12
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Ulsemer P, Toutounian K, Schmidt J, Leuschner J, Karsten U, Goletz S. Safety assessment of the commensal strain Bacteroides xylanisolvens DSM 23964. Regul Toxicol Pharmacol 2011; 62:336-46. [PMID: 22085591 DOI: 10.1016/j.yrtph.2011.10.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 10/27/2011] [Accepted: 10/29/2011] [Indexed: 11/17/2022]
Abstract
We recently isolated and characterized the new strain Bacteroides xylanisolvens DSM 23964 and presented it as potential candidate for the first natural probiotic strain of the genus Bacteroides. In order to evaluate the safety of this strain for use in food, the following standard toxicity assays were conducted with this strain in both viable and pasteurized form: in vitro bacterial reverse mutation assay, in vitro chromosomal aberration assay, and 90day subchronic repeated oral toxicity studies in mice. No mutagenic, clastogenic, or toxic effects were detected even at extremely high doses. In addition, no clinical, hematological, ophthalmological, or histopathological abnormality could be observed after necropsy at any of the doses tested. Hence, the NOAEL could be estimated to be greater than 2.3×10(11) CFUs, and 2.3×10(14) for pasteurized bacteria calculated as equivalent for an average 70kg human being. In addition, the absence of any in vivo pathogenic properties of viable B. xylanisolvens DSM 23964 cells was confirmed by means of an intraperitoneal abscess formation model in mice which also demonstrated that the bacteria are easily eradicated by the host's immune system. The obtained results support the assumed safety of B. xylanisolvens DSM 23964 for use in food.
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13
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Ochoa-Repáraz J, Mielcarz DW, Begum-Haque S, Kasper LH. Gut, bugs, and brain: role of commensal bacteria in the control of central nervous system disease. Ann Neurol 2011; 69:240-7. [PMID: 21387369 DOI: 10.1002/ana.22344] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The mammalian gastrointestinal track harbors a highly heterogeneous population of microbial organisms that are essential for the complete development of the immune system. The gut microbes or "microbiota," coupled with host genetics, determine the development of both local microbial populations and the immune system to create a complex balance recently termed the "microbiome." Alterations of the gut microbiome may lead to dysregulation of immune responses both in the gut and in distal effector immune sites such as the central nervous system (CNS). Recent findings in experimental autoimmune encephalomyelitis, an animal model of human multiple sclerosis, suggest that altering certain bacterial populations present in the gut can lead to a proinflammatory condition that may result in the development of autoimmune diseases, in particular human multiple sclerosis. In contrast, other commensal bacteria and their antigenic products, when presented in the correct context, can protect against inflammation within the CNS.
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