Publications by authors named "Tsukasa Shiraishi"

Lipoteichoic acid (LTA) is a cell surface molecule with physiologically important roles in Gram-positive bacteria. Previously, we identified a novel tetrasaccharide-containing anchor glycolipid in the Lactobacillus gasseri JCM 1131T LTA. However, it is unclear whether this tetrasaccharide-containing anchor glycolipid structure is characteristic of JCM 1131T alone or is commonly found in other L.

View Article and Find Full Text PDF

Latilactobacillus curvatus, found in various fermented foods, is a promising probiotic with unique health benefits. Lipoteichoic acid (LTA) is a characteristic amphiphilic surface polymer of Gram-positive bacteria and exhibits immunomodulatory activities. Despite the structural diversity of LTA among different bacterial species and strains, no information is available on the chemical structure of LTA in L.

View Article and Find Full Text PDF

Unlabelled: Some strains of lactic acid bacteria can regulate the host's intestinal immune system. Bacterial cells and membrane vesicles (MVs) of JCM 15950 promote immunoglobulin A (IgA) production in murine Peyer's patch cells via toll-like receptor (TLR) 2. This study aimed to investigate the role of lipoteichoic acid (LTA), a ligand of TLR2, in the immunostimulatory activity of these bacterial cells and their MVs.

View Article and Find Full Text PDF

Gram-positive bacteria, including lactic acid bacteria (LAB), possess lipoteichoic acid (LTA) on the cell surface. LTA is an amphiphilic molecule typically composed of hydrophilic glycerolphosphate polymer and hydrophobic anchor glycolipid moieties. It is involved in physiological properties of the cell surface and also plays roles in interactions with the host.

View Article and Find Full Text PDF

Lipoteichoic acid (LTA) in the gram-positive bacterial cell wall acts as an immunomodulatory factor in host cells. The chemical structures vary among bacterial species and strains, and may be related to biological activities. In our previous work, much higher immunoglobulin A (IgA)-inducing activity was observed in cells of the Apilactobacillus genus (Apilactobacillus kosoi 10H, Apilactobacillus apinorum JCM 30765, and Apilactobacillus kunkeei JCM 16173) than other lactic acid bacteria, and their LTA was responsible for the activity.

View Article and Find Full Text PDF
Article Synopsis
  • The study focuses on understanding the function of the PmrAB two-component system (TCS) in resistance to colistin, a last-resort antibiotic, in extensively drug-resistant (XDR) Gram-negative bacteria.
  • Researchers conducted transcriptome analysis to identify the regulatory genes controlled by PmrAB, revealing its responsiveness to environmental factors like pH and metal ions (Fe, Zn, Al).
  • The findings highlight PmrAB's role in both environmental adaptation and the development of antibiotic resistance by modifying lipooligosaccharide (LOS) to mitigate toxicity and enhance resistance to colistin and polymyxin B.
View Article and Find Full Text PDF

Lactic acid bacterium-containing fermentates provide beneficial health effects by regulating the immune response. A naturally fermented vegetable beverage, a traditional Japanese food, reportedly provides health benefits; however, the beneficial function of its bacteria has not been clarified. Apilactobacillus kosoi is the predominant lactic acid bacterium in the beverage.

View Article and Find Full Text PDF
Article Synopsis
  • Atrogin-1 is a key marker for muscle loss and atrophy, especially in response to dexamethasone (DEX), a medication that can induce muscle degradation.
  • Research involving C2C12 myotubes showed that components from heat-killed lactic acid bacteria (LAB) significantly reduced DEX-induced levels of atrogin-1.
  • Lipoteichoic acid (LTA) from LAB was identified as a critical factor in this suppression, particularly its glycerophosphate (GroP) component, while other forms of LTA showed varying effectiveness.
View Article and Find Full Text PDF

and are human commensal lactobacilli that are candidates for probiotic application. Knowledge of their oligosaccharide metabolic properties is valuable for synbiotic application. The present study characterized oligosaccharide metabolic systems and their impact on lipoteichoic acid (LTA) production in the two organisms, i.

View Article and Find Full Text PDF

Objectives: Intensive nutritional support during allogeneic hematopoietic stem cell transplantation (allo-HSCT) yields improved clinical outcomes. However, the clinical implications of early enteral nutrition (EN) in allo-HSCT remain unclear. This retrospective study was conducted to determine the significance of early EN in individuals who underwent allo-HSCT, and the association between early nutritional intervention and clinical outcomes, including the status of the intestinal microbiome.

View Article and Find Full Text PDF

Acetic acid treatment [98% (v/v), 100 °C, 3 h] was proposed as a new method for degrading the glycerophosphate polymer moiety of Gram-positive bacterial lipoteichoic acid. We demonstrated that this method resulted in partial O-acetylation on the carbohydrate residues of the anchor glycolipid. Hence, the acetic acid treatment is not suitable for the chemical structural analysis of lipoteichoic acid.

View Article and Find Full Text PDF

β-Lactam-resistant is a clinical concern. A high prevalence (>40%) of β-lactamase-negative high-level ampicillin-resistant (high-BLNAR) isolates in Japan has been reported. However, the reasons for the expansion are unknown.

View Article and Find Full Text PDF

Colistin is a last-line drug for multidrug-resistant Gram-negative bacteria. We previously reported four plasmid-mediated colistin resistance () gene-negative colistin-resistant clinical isolates, including the major pathogenic and fluoroquinolone-resistant strains O25b:H4-ST131-30Rx (isolates SRE34 and SRE44; MIC for colistin = 16 mg/liter), non-x (SME296; MIC = 8 mg/liter), and O18-ST416 (SME222; MIC = 4 mg/liter). In this study, we investigated the colistin resistance mechanism and identified novel amino acid substitutions or deletions in the PmrAB two-component system that activates (encoding a phosphoethanolamine transferase) and (encoding an undecaprenyl phosphate-alpha-4-amino-4-deoxy-l-arabinose arabinosyl transferase) in all colistin-resistant isolates.

View Article and Find Full Text PDF
Article Synopsis
  • Multidrug-resistant strains of Streptococcus pneumoniae were isolated from a patient in Sapporo, Japan, showing resistance to many antibiotics and only sensitivity to a few.
  • The isolates shared the same serotype (19F) and genetic sequence (ST10017), indicating they likely come from a common source, with a previously identified strain showing different resistance patterns.
  • Whole genome sequencing revealed several resistance mutations and genes, suggesting that the strain MDRSPN001 is evolving rapidly through genetic changes and acquiring resistance traits from other bacteria, including oral streptococci.
View Article and Find Full Text PDF

Pseudomonas aeruginosa is an important etiological agent of opportunistic infections. Injectable colistin is available as a last-line treatment option for multidrug-resistant P. aeruginosa infections.

View Article and Find Full Text PDF

The plaque-forming assay is the standard technique for determining viral titer, and a critical measurement for investigating viral replication. However, this assay is highly dependent on experimental technique and conditions. In the case of human respiratory syncytial virus (RSV) in particular, it can be difficult to objectively confirm the accuracy of plaque-forming assay because the plaques made by RSV are often small and unclear.

View Article and Find Full Text PDF

Transmission of tigecycline-nonsusceptible pathogenic Enterobacteriaceae from companion animals to human should be a concern because tigecycline is a last-line drug for treating multidrug-resistant Enterobacteriaceae in human medicine. However, tigecycline susceptibility of Enterobacteriaceae isolated from companion animals has not been investigated. In this study, we investigated the tigecycline susceptibility of Klebsiella pneumoniae complex and Escherichia coli isolates from dogs and cats, and evaluated their human pathogenicity potential.

View Article and Find Full Text PDF
Article Synopsis
  • The study focuses on a serious issue: infections caused by multidrug-resistant bacteria.
  • Researchers present the full genome sequence of a specific strain called serotype 19F.
  • This strain was taken from a patient in Sapporo, Japan, highlighting the ongoing health threat posed by drug-resistant infections.
View Article and Find Full Text PDF

We recently isolated a tumoricidal peptide from Natto, a Japanese traditional fermented food. In the present study, antimicrobial activity of the Natto peptide was examined. The peptide consisted of 45 amino acid residues, and its structure was predicted to be rich in α-helix.

View Article and Find Full Text PDF

In recent years, multidrug resistance of has become a serious problem. However, resistance to fosfomycin (FOM) has been low. We screened clinical isolates with reduced susceptibility to FOM and characterized molecular mechanisms of resistance and reduced susceptibility of these strains.

View Article and Find Full Text PDF

NIP-SNAP-1 and -2 are ubiquitous proteins thought to be associated with maintenance of mitochondrial function, neuronal transmission, and autophagy. However, their physiological functions remain largely unknown. To elucidate their functional importance, we screened for proteins that interact with NIP-SNAP-1 and -2, resulting in identification of HSP60 and P62/SQSTM1 as binding proteins.

View Article and Find Full Text PDF
Article Synopsis
  • - Macrolide antibiotics, such as clarithromycin (CAM), can help reduce inflammation in respiratory diseases by affecting immune responses, although the exact molecular mechanisms are still unclear.
  • - Research identified specific mitochondrial proteins (NIP-SNAP-1, NIP-SNAP-2, and VLCAD) that are bound by CAM and play a role in regulating inflammation.
  • - Knocking down NIP-SNAP-1 or -2 reduced the production of pro-inflammatory cytokines (IL-8 and IL-6) and dampened NF-κB activity, indicating that CAM modulates inflammation by targeting these mitochondrial proteins.
View Article and Find Full Text PDF

Bacterial cell surface molecules are at the forefront of host-bacterium interactions. Teichoic acids are observed only in Gram-positive bacteria, and they are one of the main cell surface components. Teichoic acids play important physiological roles and contribute to the bacterial interaction with their host.

View Article and Find Full Text PDF