Добірка наукової літератури з теми "ST285"

Probiotic bacteria have beneficial effects to the development and maintenance of a healthy microflora that subsequently has health benefits to humans. Some of the health benefits attributed to probiotics have been noted to be via their immune modulatory properties suppressing inflammatory conditions. Hence, probiotics have become prominent in recent years of investigation with regard to their health benefits. As such, in the current study, we determined the effects of Streptococcus thermophilus to agonist MBP83–99 peptide immunized mouse spleen cells. It was noted that Streptococcus thermophilus induced a significant increase in the expression of anti-inflammatory IL-4, IL-5, IL-10 cytokines, and decreased the secretion of pro-inflammatory IL-1β and IFN-γ. Regular consumption of Streptococcus thermophilus may therefore be beneficial in the management and treatment of autoimmune diseases such as multiple sclerosis.

Recently, we reported the purification and characterization of three distinct lantibiotics (named suicin 90-1330, suicin 3908, and suicin 65) produced by Streptococcus suis. In this study, we investigated the distribution of the three suicin lantibiotic gene clusters among serotype 2 S. suis strains belonging to sequence type (ST) 25 and ST28, the two dominant STs identified in North America. The genomes of 102 strains were interrogated for the presence of suicin gene clusters encoding suicins 90-1330, 3908, and 65. The gene cluster encoding suicin 65 was the most prevalent and mainly found among ST25 strains. In contrast, none of the genes related to suicin 90-1330 production were identified in 51 ST25 strains nor in 35/51 ST28 strains. However, the complete suicin 90-1330 gene cluster was found in ten ST28 strains, although some genes in the cluster were truncated in three of these isolates. The vast majority (101/102) of S. suis strains did not possess any of the genes encoding suicin 3908. In conclusion, this study indicates heterogeneous distribution of suicin genes in S. suis.

Hospital environments constitute the main reservoir of multidrug-resistant bacteria. In this study we aimed to investigate the presence of Gram-negative bacteria in one Northwestern Tunisian hospital environment, and characterize the genes involved in bacterial resistance. A total of 152 environmental isolates were collected from various surfaces and isolated using MacConkey medium supplemented with cefotaxime or imipenem, with 81 fermenter bacteria (27 Escherichia coli, and 54 Enterobacter spp., including 46 Enterobacter cloacae), and 71 non-fermenting bacteria (69 Pseudomonas spp., including 54 Pseudomonas aeruginosa, and 2 Stenotrophomonas maltophilia) being identified by the MALDI-TOF-MS method. Antibiotic susceptibility testing was performed by disk diffusion method and E-Test was used to determine MICs for imipenem. Several genes implicated in beta-lactams resistance were characterized by PCR and sequencing. Carbapenem resistance was detected among 12 isolates; nine E. coli (blaNDM-1 (n = 8); blaNDM-1 + blaVIM-2 (n = 1)) and three P. aeruginosa were carbapenem-resistant by loss of OprD porin. The whole-genome sequencing of P. aeruginosa 97H was determined using Illumina MiSeq sequencer, typed ST285, and harbored blaOXA-494. Other genes were also detected, notably blaTEM (n = 23), blaCTX-M-1 (n = 10) and blaCTX-M-9 (n = 6). These new epidemiological data imposed new surveillance strategies and strict hygiene rules to decrease the spread of multidrug-resistant bacteria in this area.

The study’s aim was to analyze the population structure of enterococci causing human invasive infections in a medium-sized Argentinian Hospital coincidental with a 5 year-period of increased recovery of antibiotic resistant enterococci (2010–2014). Species identification (biochemical testing/MALDI-TOF-MS), antimicrobial susceptibility (disk-diffusion) and clonal relatedness (PFGE/MLST/BAPS) were determined according to standard guidelines. β-lactamase production was determined by a nitrocefin test and confirmed by PCR/sequencing. The isolates were identified as Enterococcus faecalis and Enterococcus faecium at a 2:1 ratio. Most of the E. faecalis isolates, grouped in 25 PFGE-types (ST9/ST179/ST236/ST281/ST388/ST604/ST720), were resistant to high-levels (HLR) of gentamicin/streptomycin. A ST9 clone (bla+/HLR-gentamicin) was detected in patients of different wards during 2014. E. faecium isolates were grouped in 10 PFGE-types (ST25/ST18/ST19/ST52/ST792), with a low rate of ampicillin resistance. Five vancomycin-resistant E. faecium, three vanA (ST792/ST25) and two vanB (ST25) were detected. The ST25 clone carried either vanA or vanB. The recovery of a bla+-ST9-E. faecalis clone similar to that described in the late 1980s in Argentina suggests the possibility of a local hidden reservoir. These results reflect the relevance of local epidemiology in understanding the population structure of enterococci as well as the emergence and spread of antimicrobial resistance in predominant enterococcal clonal lineages.

Blastocystis is a common food- and water-borne intestinal protist parasite of humans and many other animals. Blastocystis comprises multiple subtypes (STs) based on variability within the small subunit ribosomal (SSU rRNA) RNA gene. Though full-length reference sequences of the SSU rRNA gene are a current requirement to name a novel Blastocystis subtype, full-length reference sequences are not currently available for all subtypes. In the present study, Oxford Nanopore MinION long-read sequencing was employed to generate full-length SSU rRNA sequences for seven new Blastocystis subtypes for which no full-length references currently exist: ST21, ST23, ST24, ST25, ST26, ST27, and ST28. Phylogenetic analyses and pairwise distance matrixes were used to compare full-length and partial sequences of the two regions that are most commonly used for subtyping. Analyses included Blastocystis nucleotide sequences obtained in this study (ST21 and ST23–ST28) and existing subtypes for which full-length reference sequences were available (ST1–ST17 and ST29). The relationships and sequence variance between new and existing subtypes observed in analyses of different portions of the SSU rRNA gene are discussed. The full-length SSU rRNA reference sequences generated in this study provide essential new data to study and understand the relationships between the genetic complexity of Blastocystis and its host specificity, pathogenicity, and epidemiology.

Leptospirosis is a zoonotic disease caused by pathogenic spirochetes of Leptospira species. It is a public health issue in the tropics, including Okinawa, the southernmost prefecture of Japan. This study reports the first isolation of L. interrogans serogroup Sejroe from two human patients in Japan, and describes its molecular characterization using multilocus sequence typing (MLST) and multiple-locus variable-number tandem repeat analysis (MLVA). MLST on the two isolates, 168036 and 178129, showed that pfkB in 178129 is a novel allele, and that both isolates constitute novel sequence types (STs); ST286 for 168036 and ST287 for 178129. A minimum spanning tree based on seven alleles of L. interrogans indicates that both isolates are genetically close, but are distinct from known L. interrogans serogroup Sejroe strains. MLVA using 11 loci demonstrated that seven of the 11 loci were identical between the two isolates, whereas the identity between the isolates and the seven reference strains of L. interrogans serogroup Sejroe was zero to three loci. These results indicate that the isolates investigated in this study have novel genotypes, and are genetically closest to each other among the known L. interrogans serogroup Sejroe strains.

Cryptococcus neoformans is an environmental fungal pathogen that causes opportunistic infections and severe disseminated meningoencephalitis, mainly in immunocompromised patients such as those with acquired immunodeficiency syndrome (AIDS). In this study, the clinical characteristics, treatment protocols, and outcomes of 70 patients with AIDS and Cryptococcus neoformans infection at Beijing Ditan Hospital were retrospectively analyzed. We performed antimicrobial sensitivity tests and multilocus sequence typing (MLST) on C. neoformans isolates from these patients. The most common symptoms were headache (58.6%), fever (54.3%), and high cerebrospinal fluid pressure (≥200 mm H2O) (71.4%). All patients were positive for C. neoformans antigen in blood or cerebrospinal fluid. The CD4 cell counts of 92.8% (65/70) of patients were <100 cells/µL. In total, 74 C. neoformans isolates were obtained from the 70 patients. The 65 isolates that could be typed fell into 12 sequence types (STs) by MLST: ST5, ST31, ST63, ST202, ST237, ST289, ST295, ST296, ST298, ST324, ST337, and ST359. ST5 was the major type, accounting for 78.5% of isolates (51/65). This study comprehensively assessed the clinical and molecular epidemiology of C. neoformans in patients with AIDS and may inform the development of targeted prevention and treatment strategies for immunocompromised patients with C. neoformans infection.

The emergence of extended-spectrum cephalosporin (ESC)-resistant Gram-negative bacteria is of great concern in both human and veterinary medicine. The aim of this study was to investigate ESC-resistant bacterial isolates from companion animals in South Korea between 2017 and 2019. Isolates with ESC resistance genes, which were identified by PCR, were assessed for genetic relatedness by multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). In total, 91 ESC-resistant Escherichia coli, Klebsiella spp., Serratia spp., and Enterobacter cloacae isolates harbored the blaTEM gene. Among other ESC resistance genes, blaCTX-M-15, blaCIT, and blaCTX-M-55 were predominantly detected in E. coli isolates, whereas blaSHV and blaDHA were more frequently detected in Klebsiella pneumoniae isolates. In addition, all blaEBC-positive isolates were classified as E. cloacae. From the MLST results, blaCTX-M-9-carrying ST131, blaCIT-carrying ST405, and blaCTX-M-1-carrying ST3285 strains were dominant among E. coli isolates. ST273 and ST275 strains harboring blaSHV were frequently detected in K. pneumoniae isolates. Various sequence types were obtained in E. cloacae and Klebsiella oxytoca isolates. All isolates demonstrated unique PFGE profiles (<57–98% similarity) and were unlikely to be derived from a single clone. The present study reveals the presence and wide genetic distribution of ESC-resistant bacterial species in South Korean companion animals.

Introduction: Klebsiella pneumoniae sequence type 258 (ST258) strains are globally distributed multi-drug resistant pathogens and can spread rapidly throughout the world, causing severe healthcare-associated invasive infections with limited antimicrobial treatment options. The aim of this study was to reveal the incidence of Klebsiella pneumoniae ST258 strains among the intensive care unit patients in a university hospital in Istanbul. Methodology: Consecutive nonreplicated 83 K. pneumoniae strains were isolated from various clinical samples of intensive care unit patients admitted to a university hospital in Istanbul, between November 2016 to December 2018. Bacterial identifications were performed via VITEK2. Antimicrobial susceptibility tests were conducted with Kirby Bauer’s disc diffusion test except for colistin which was performed with broth microdilution. Real-time PCR method was utilized in order to reveal ST258 positivity among the strains. Results: Antimicrobial susceptibility results revealed that 56 (67%) K. pneumoniae strains were carbapenem-resistant. Real-time PCR results demonstrated that 15 out of 83 (18%) K.pneumoniae strain were ST258. According to antimicrobial susceptibility test results of ST258 strains, 8 were found as carbapenem-resistant whereas 7 were found as carbapenem susceptible. 3 out of 8 (37.5%) carbapenem-resistant ST258 strains were found as resistant against all antibiotics tested. Conclusions: Our study revealed that K. pneumoniae ST258 which caused severe infections worldwide so far has also spread to Istanbul. We believe that rapid molecular methods for monitorization of these clones are useful. our results showed that ST258 is not linked to a multi-resistant strain and suggested that it does not contribute to multi-resistance formation alone.

Abstract Introduction : Myeloid differentiation primary response gene 88 (MYD88) is an adaptor protein that binds to the Toll-like/interleukin-1 receptor to form a homodimer and activates NF-kB pathway. Activating MYD88 mutations are found in 90% of lymphoplasmacytic lymphoma (Waldenström's macroglobulinemia) cases and 30% of activated B-cell type diffuse large B-cell lymphoma (DLBCL) cases. To investigate the role of MYD88 in the growth of lymphoma/leukemia cells, with or without MYD88mutations, and to examine whether MYD88 inhibitors can be used as novel molecular-targeted drugs, we studied their effects on the growth of lymphoma and leukemia cells in vitro. Methods : Seven lymphoma/leukemia cell lines (TMD8 derived from DLBCL with MYD88 mutations, Daudi from Burkitt lymphoma, NALM-6 from B-ALL, Jurkat and KOPT-K1 from T-ALL, THP-1 and TMD7 from AML without MYD88 mutations) and normal lymphocytes from healthy volunteers were obtained, following an informed consent. The effect of the MYD88 inhibitor, ST2825, on the in vitro growth of these cell lines was then examined using the WST-8 colorimetric assay. ST2825 is a synthetic peptide-mimetic compound, which inhibits MYD88 dimerization. A Bruton tyrosine kinase (BTK) inhibitor, ibrutinib, was used as the reference inhibitor. The effect of ST2825 on protein expression was examined by immunoblot analysis. Cell cycle analysis and Annexin V apoptosis assay were performed using flow cytometry. To comprehensively screen the changes in mRNA expression after ST2825 treatment, microarray analysis was performed for TMD8 and Jurkat cells. MYD88knockdown experiments using small interfering RNA were also performed. Results : The MYD88 protein was expressed in all cell lines. ST2825 (30 μM) suppressed the growth of all lymphoma/leukemia cell lines, but did not affect the viability of normal lymphocytes. The IC50 for TMD8 cells was similar to that for other cells, such as Daudi cells. Apoptosis assay revealed that ST2825 induces apoptosis in all the cell lines studied. In Daudi cells, ST2825 induced G2/M cell cycle arrest. Immunoblot analysis revealed that ST2825 suppresses the phosphorylation of certain NF-kB signaling components, such as RELA and IkB, in all cell lines. In TMD8, Daudi, and NALM-6 cells, ST2825 suppressed the phosphorylation of BTK, and MYD88 knockdown suppressed the phosphorylation of RELA and BTK. Microarray analysis revealed that ST2825 treatment downregulates the expression of various genes including MYD88, and upregulates the expression of other genes such as NGFR, FOSB, and HSP. Treatment with ibrutinib (1 nM) suppressed the growth of only TMD8 cells. Treatment with ST2825 plus ibrutinib additively suppressed the growth of TMD8 cells. Conclusions : The MYD88 inhibitor ST2825 suppresses the growth of various lymphoma and leukemia cells, suggesting that MYD88 is involved in regulating the growth of these cells; however, the off-target effects of ST2825 should be considered. Further investigation is required to assess the potential of MYD88 inhibitors as novel molecular-targeted drugs against lymphoma and leukemia. Disclosures No relevant conflicts of interest to declare.

This project provides a novel insight into the genetics of complex surface structures present in the ST25 lineage of the multi-drug resistant bacteria, Acinetobacter baumannii. The thesis employs a newly developed tool, Kaptive, to aid global tracking efforts of this pathogen and uncovers new structure variants which inform future therapeutic options.

KPC (Klebsiella pneumoniae carbapenemases) são -lactamases da classe A de Ambler globalmente disseminadas, com 10 variantes, sendo predominates KPC-2 e KPC-3. O objetivo deste trabalho foi estudar a genética e epidemiologia molecular de enterobactérias resistentes aos carbapenêmicos isoladas no Brasil. Sessenta e quatro enterobactérias resistentes aos carbapenêmicos foram analisadas: 57 Klebsiella pneumoniae (Kp), 5 Enterobacter cloacae (Ecl), 1 Serratia marcescens (Sm) e 1 Citrobacter freundii (Cf), de diferentes pacientes, em seis hospitais e em duas distintas regiões do Brasil. Identificação e testes de sensibilidade antimicrobiana foram realizados por sistemas semi-automáticos e métodos padronizados. A relação clonal foi estabelecido por Pulsed-field gel electrophoresis (PFGE) e também por tipagem por sequenciamento de multilocus no caso de K. pneumoniae. A presença de genes que codificam carbapenemases e -lactamases de espectro estendido foi pesquisada. A caracterização de blaKPC-2, do ambiente genético e de plasmídeos incluiu PCR e sequenciamento, análises de RFLP, S1-PFGE e hibridação. Os isolados Kp corresponderam a 5 pulsotipos, por PFGE, ligados a 6 tipos de sequência (ST): KPA-ST258 (n = 51 com 6 subtipos), KpA6-ST11 (n = 1), KPB-ST327 (n = 1), KPC-ST44 (n = 2), KPD-ST437 (n = 1) e KPE-ST48 (n = 1). Ecl foram agrupados em clones e e, Sm e Cf representam um clone cada. Todos os isolados foram resistentes aos -lactâmicos, sensíveis à colistina e tigeciclina e mostraram fenótipos variáveis contra aminoglicosídeos, quinolonas, nitrofurantoína e sulfametoxazol-trimetoprim. Heterorresistência a carbapenêmicos foi observada para isolados de Kp e Cf, conforme relatado anteriormente com produtores de KPC-2 e VIM. Esse estudo relata a disseminação do gene blaKPC-2 nos estados de São Paulo e Rio de Janeiro facilitada por clones de K. pneumoniae pertencentes ao globalmente disseminado Complexo Clonal CC258 (ST258, ST437 e ST11) e uma diversidade de plasmídeos (IncFII-KpA, IncN-Kp e Ecl, IncL/M-Sm e Cf e, dois plasmídeos não-tipáveis carreando Tn4401a ou Tn4401b) disseminados com sucesso entre as enterobactérias. Constitui também a primeira descrição do ST258 no Brasil associada a um surto em um hospital universitário da cidade de Ribeirao Preto. Este trabalho apontou a alta diversidade de elementos genéticos disponíveis abrigando blaKPC-2. Isso poderia ampliar enormemente a disseminação desse gene no Brasil como também no continente.
KPC (Klebsiella pneumoniae carbapenemases) are globally spread -lactamases of the Ambler class A comprising 10 variants, KPC-2 and KPC-3 being predominant. The objective of this work was study the genetic and molecular epidemiology of carbapenem resistant-enterobacterial isolates in Brazil. Sixty-four carbapenem resistant isolates were analyzed: 57 Klebsiella pneumoniae (Kp), 5 Enterobacter cloacae (Ecl), 1 Serratia marcescens (Sm) and 1 Citrobacter freundii (Cf) from different patients at six hospitals in two different Brazilian regions. Identification and antimicrobial susceptibility testing were accomplished by using semiautomatic systems and standard methods. Clonal relatedness was established by Pulsed-Field Gel Electrophoresis (PFGE) and also by multilocus sequence typing in the case K. pneumoniae isolates. The presence of genes encoding carbapenemases and extended spectrum -lactamases was searched. Characterization of blaKPC-2, genetic environment and plasmids included PCR and further sequencing, RFLP analyses, S1-PFGE and hybridization. The Kp isolates corresponded to 5 PFGE types linked to 6 sequence types (ST): KpA-ST258 (n=51 comprising 6 subtypes), KpA6-ST11 (n=1), KpB-ST327 (n=1), KpC-ST44 (n=2), KpD-ST437 (n=1) and KpE-ST48 (n=1). Ecl isolates were grouped in and clones and, Sm and Cf represent one clone each. All isolates were resistant to -lactams, susceptible to colistin and tigecycline and showed variable phenotype against aminoglycosides, quinolones, nitrofurantoin and trimethoprim-sulfamethoxazole. Heteroresistance to carbapenems was observed for Kp and Cf isolates, as previously reported to KPC-2 and VIM producers. This study reports the spread of blaKPC-2 in Sao Paulo and Rio de Janeiro states facilitated by globally spread CC258-K. pneumoniae clones (ST258, ST11, ST437) and a diversity of plasmids (IncFII-KpA, IncN-Kp and Ecl, IncL/M-Sm and Cf and, two untypeable plasmids carrying Tn4401a or Tn4401b) successfully disseminated among Enterobacteriaceae species. It also constitutes the first description of ST258 in Brazil which was associated with a hospital outbreak in Ribeirao Preto city. This work pointed out the high diversity of available genetic elements harboring blaKPC-2. This might greatly amplify the dissemination of KPC genetic in Brazil and within of the South America continent.

Changes in physiological, immunological and gut microbiome can lead to a range of chronic conditions in humans. The ‘hygiene hypothesis’ identifies the increasing trend of immune-mediated disorders to possibly be a consequence of intestinal dysbiosis, that in turn results in a dysfunctional immune system leading to conditions such as, eczema, asthma, allergies and autoimmune diseases. Therefore, utilization of beneficial probiotic bacteria can increase their abundance within the gastrointestinal lumen, and subsequently modulate immune cells, such as, T helper (Th)-1, Th2, Th17, regulatory T (Treg) cells, B cells, macrophages, dendritic cells and monocytes. Modulation of immune cells are directly related to human health and pathogenesis of immune disorders. Chapter 1a describes the cross talk between probiotics and the gastrointestinal immune system, and their effects in relation to inflammatory bowel disease, multiple sclerosis (MS), allergies and atopic dermatitis. MS is one of the debilitating autoimmune disease of the central nervous system which has been increasing during the past decades. MS severely affects patients’ health, work and quality of life, and its treatment has changed over the last 20 years. In chapter 1b the immunopathology of MS and various available treatments have been investigated. As all the MS immunotherapeutic drugs target relapsing remitting MS (RRMS), in particular developing a treatment for progressive forms of MS is a medical challenge and medical specialists and clinicians are in constant battle with serious treatment challenges for MS. Although β- interferons 1a or 1b and glatiramer acetate are accounted as the most commonly used injectable disease modifying therapies in RRMS, however, one of the major challenge of these types of therapies has been the lack of devotion to treatment among MS patients, with approximately 50% of patients ceasing their therapy plan within the first year. This chapter revisits the basics of the immune-pathophysiology of MS to gain insights in the development of innovative improved drug treatments and presents current drug treatments and new and emerging immune modulating approaches for the immunotherapy of MS. This chapter provides groundwork for vaccine (or immune modulation) development research and the investigation of new potential vaccines (immune modulators) against MS which are used in chapters 5a and 5b. Backtracking probiotics beneficial effects to the host that occur through their contribution to the development and maintenance of a healthy immune system, tracked the steps to the use of some probiotics in the food industry as starter or secondary starter cultures to ferment dairy products. These probiotics include Streptococcus thermophilus (ST); in chapter 2, ST1275, ST285 and ST1342 bacteria were used to determine their modulatory effects on U937 human promonocytic cell line which exhibited differential cytokine induction, in particular, increased secretion of anti-inflammatory IL-4 and IL-10 cytokines were noted. ST also stimulated an increase in the production of CXCL8 and GM-CSF, as well as expression of cell surface markers, CD11c, CD86, C206, CD209, MHC-1. ST285 was determined the most potent probiotic, therefore was considered to investigate further in chapters 3, 4 and 6. The main objective of next study was to assess modulatory and anti-inflammatory properties of ST285 using human peripheral blood mononuclear cells (PBMC) from healthy donors. To fulfil this objective, modifications in the mRNA expression of genes related to innate and adaptive immunity were assessed and results showed strong immune modulatory effects of ST285 to human PBMC with an array of anti-inflammatory properties. ST285 reduced mRNA expression of IL-18, IFNγR1, CCR5, CXCL10, TLR-1, TLR-2, TLR-4, TLR-8, CD14, CD40, CD86, C3, GATA3, ITGAM, IRF7, NLP3, LYZ, TYK2 and IFNR1. ST285 upregulated IL- 1α, IL-1β, IL-6, IL-8, IL-10, IL-23, IFNγ, TNFα, CSF-2 to human PBMC; no changes to mRNA expression of IFNA1, IFNB1, IL-4, IL-5, IL-13, CCL2, CCL5, CCL8, CCR4, CCR8, CXCR3, TLR-3, TLR-5, TLR-6, TLR-9, CD4, CD80, FOXP3, STAT3, CD40LG, HLA-A, HLA-E and RORC were noted. These data demonstrated a predominant anti-inflammatory profile exhibited by ST285, hence, ST285 was validated for further investigation on human monocytes. Some of the beneficial effects attributed to probiotics may be through modulation of the immune system; the effect of ST285 to human monocytes was assessed and a range of immune modulating effects of ST285 by human monocytes was demonstrated. This included significant downregulation in the mRNA expression of IL-1R, IL-18, IFNγR1, IFNαR1, CCL2, CCR5, TLR-1, TLR-2, TLR-4, TLR-5, TLR-6, TLR-8, CD14, CD86, CD4, ITGAM, LYZ, TYK2, IFNR1, IRAK-1, NOD2, MYD88, ITGAM, SLC11A1, and significant upregulation in the mRNA expression of IL-1α, IL-1β, IL-2, IL-6, IL-8, IL-23, IFNγ, TNFα, and CSF-2. ST285 is used in the dairy industry, survives during cold storage, well tolerates upon ingestion, and their consumption may have beneficial effects with potential implications in inflammatory and autoimmune disorders, such as, multiple sclerosis. In order to determine a suitable autoimmune setting to investigate the effects of ST285 in an animal model, it was required to revisit MS treatments to determine the effects of recently developed agonist and antagonist MS vaccines. Encephalitogenic T cells are greatly implicated in the pathogenesis of MS, stimulation of these T calls is triggered by the formation of a tri- molecular complex among the human leukocyte antigen (HLA), an immunodominant myelin basic protein (MBP) epitope, and the T cell receptor (TCR). This next study (chapter 5) concentrated on the rational design and synthesis of non-peptide mimetic molecules, based on the immunodominant MBP83–96 epitope that is recognized by the TCR in complex with HLA, with a focused attention on the inhibition of the tri-molecular complex formation which can consequently lead to the inhibition of proliferation of activated T cells. In view of the interactions between the TCR and the HLA-MBP83–96 complex, a structure-based pharmacophore model was generated and the newly candidate molecules were obtained through the ZINC database, six molecules were synthesized and further evaluated in vitro as TCR antagonists. Analogues 15 and 16 were able to inhibit the stimulation of T cells by the immunodominant MBP83–99 peptide from immunized mice to some extent, and to a lesser degree by analogues 17 and 18 and then by analogue 19, presenting the lead compounds 15 and 16 may be used for immunotherapy against MS. In addition in chapter 5b, the immune modulatory effects of MBP83-99 peptide conjugated or not conjugated to carrier mannan, in either linear or cyclic forms were determined. It was shown that MBP83-99 modulated the immune responses in SJL/J immunized mice which resulted in cytokine secretion by immunized spleen cells which was protective in an experimental autoimmune encephalitis model and protection against axonal spinal damage. Molecular modelling was used to gain insights into the binding mode of the peptide to MHC class II. In the chapter 6, the effects of ST285 to agonist MBP83-99 peptide immunized mouse spleen cells was determined. Agonist peptide induced a Th1 profile, however in the presence of ST285 a significant increase in the expression of anti-inflammatory IL-4, IL-5, IL-10 cytokines,and decreased pro-inflammatory IL-1β and IFN-γ were noted. Regular consumption of probiotic bacteria such as ST285 in the form of capsules, fermented food or dairy products may therefore be beneficial in the management and treatment of autoimmune diseases such as multiple sclerosis. Consumption of probiotics contributes to a healthy microbiome of the GIT leading to many health benefits. They also contribute to the modulation of the immune system and are becoming popular for the treatment of a number of immune and inflammatory diseases.

碩士
實踐大學
食品營養與保健生技學系碩士班
103
Soybean derived products are oriental traditional foods and a lot of people are used to taking them as convenient and instant protein supplements especially in the form of soymilk. In order to cut the production cost, most packaged soymilk producers may add artificial thickeners in their products to enhance texture qualities. This study is thus conducted to investigate the feasibility of using natural exoplysaccharides (EPS) produced by lactobacilli strains as texturing agents to substitute artificial thickeners. Lactic acid bacterial strains having the high yield of EPS production were screened and the effects of different carbon sources on their EPS production were also explored. The domestic soybean harvested from a Kaohsiung 10 soybean strain was used to make soymilk for fermentation. Several screened lactobacilli strains were then used to ferment soymilk additionally spiked with 0%, 2%, and 4% of glucose respectively for 8 hours at 37℃, followed by storage at 4% for 7 days. The bacterial counts, pH, EPS concentration, viscosity, and titratable acidity were analyzed. The results showed that 22 trains screened from more than 100 strains of lactic acid bacteria gave high yields of EPS with concentrations more than 200 mg/L. Among them, 4 potential probiotic strains, ST74, ST85, ST88, and ST94, were selected for further studies based on their acceptable resistance of acids, tolerance of bile salts, and meeting of gastrointestinal tract simulation test. Strain identification of three strains by API 50 kits indicated that they are Lactobacillus fermentum ST74, Lactobacillus fermentum ST85, and Lactobacillus buchneri ST88 respectively. Glucose was a better carbon source in exopolysaccharide production, showing a positively direct correlation of increasing EPS yields with increasing glucose addition, compared to fructose with a negative correlation. At a concentration of 4% glucose, strain ST85 exhibited the highest production of EPS, resulting in a concentration of 350 mg/L. The increasing viscosity of fermented soymilk by L. fermentum ST85 was correlated with increasing EPS production, suggesting that this strain may have the potential as a fermentative probiotics in soymilk fermentation, but still requiring a further study on the feasibility of its