A novel aluminum-tolerant bacterial strain CA42 was isolated from the aquatic plant , which grows in a highly acidic swamp in Vietnam. Inoculation with CA42 allowed to grow in the presence of 300 μM AlCl at pH 3.5, and biofilms were observed around the roots.
View Article and Find Full Text PDFCryptococcus gattii is a capsular pathogenic fungus causing life-threatening cryptococcosis. Although the capsular polysaccharides (CPs) of C. gattii are considered as virulence factors, the physiological significance of CP biosynthesis and of CPs themselves is not fully understood, with many conflicting data reported.
View Article and Find Full Text PDFAcid sulfate soil is found throughout Southeast Asia, and its strong acidity (pH 2-4) is accompanied by various plant growth-inhibiting factors that can reduce crop production. Among these factors, aluminum elution from the soil due to soil acidity strongly inhibits crop growth and is particularly problematic for agricultural production. We previously isolated Acidocella aluminiidurans strain AL46, a highly aluminum-tolerant bacterium, from the rhizospheres of the grass Panicum repens, inhabiting the acid sulfate soil in Vietnam.
View Article and Find Full Text PDFJ Antibiot (Tokyo)
October 2020
Lascivol was identified as the bitter compound in two Tricholoma species, T. aestuans and T. virgatum, and was previously isolated from the European mushroom T.
View Article and Find Full Text PDFZymosan is a glucan that is a component of the yeast cell wall. Here, we determined the mechanisms underlying the zymosan-induced accumulation of neutrophils in mice. Loss of the receptor CD300b reduced the number of neutrophils recruited to dorsal air pouches in response to zymosan, but not in response to lipopolysaccharide (LPS), a bacterial membrane component recognized by Toll-like receptor 4 (TLR4).
View Article and Find Full Text PDFLeukocyte mono-immunoglobulin-like receptor (LMIR)/CD300 proteins comprise a family of immunoglobulin-like receptors that are widely expressed on the immune cell surface in humans and mice. In general, LMIR3/CD300f suppresses the inflammatory response, but it can occasionally promote it. However, the precise roles of LMIR3 in the function of neutrophils remain to be elucidated.
View Article and Find Full Text PDFTissue-resident memory T cells (TRMs) are a novel nonvascular memory T cell subset. Although CD8 TRMs are well-characterized, CD4 TRMs-especially lung-resident memory Th17 cells-are still being defined. In this study, we characterized lung-resident memory Th17 cells (lung TRM17) and their role in protection against the highly virulent fungus Cryptococcus gattii.
View Article and Find Full Text PDFPoor pharmacokinetic parameters are a major reason for the lack of therapeutic activity of some drug candidates. Determining the pharmacokinetic parameters of drug candidates at an early stage of development requires an inexpensive animal model with few associated ethical issues. In this study, we used the silkworm infection model to perform structure-activity relationship studies of an antimicrobial agent, GPI0039, a novel nitrofuran dichloro-benzyl ester, and successfully identified compound 5, a nitrothiophene dichloro-benzyl ester, as a potent antimicrobial agent with superior therapeutic activity in the silkworm infection model.
View Article and Find Full Text PDFWe screened innate immunostimulant-producing bacteria using a silkworm muscle contraction assay, and isolated Rhizobium sp. strain M2 from soil. We purified the innate immunostimulant from strain M2, and characterized the chemical structure by nuclear magnetic resonance spectroscopy and chemical analyses.
View Article and Find Full Text PDFVegetables are eaten as part of a healthy diet throughout the world, and some are also applied topically as a traditional medicine. We evaluated the innate immunostimulating activities of hot water extracts of various vegetables using the silkworm muscle contraction assay system, and found that broccoli, Brassica oleracea var. italica, contains a strong innate immunostimulant.
View Article and Find Full Text PDFSepsis is a serious clinical problem. Negative regulation of innate immunity is associated with sepsis progression, but the underlying mechanisms remains unclear. Here we show that the receptor CD300f promotes disease progression in sepsis.
View Article and Find Full Text PDFCryptococcosis caused by highly virulent Cryptococcus gattii (Hv-Cg) is an emerging infectious disease that affects immunocompetent individuals. The Hv-Cg outbreak began in 1999, but the mechanisms responsible for its hyper-virulence as well as protective immunity against Hv-Cg infection remain to be elucidated. To better understand the protective immunity against Hv-Cg infection, we developed a novel immunization method using antigen-pulsed dendritic cells (DCs).
View Article and Find Full Text PDFSeveral pathogenic fungi, including Cryptococcus gattii, Histoplasma capsulatum, Coccidioides immitis, and Penicillium marneffei, cause serious infectious diseases in immunocompetent humans. However, currently, prophylactic and therapeutic vaccines are not clinically used. In particular, C.
View Article and Find Full Text PDFCryptococcus neoformans causes life-threatening diseases mainly in immunosuppressed hosts such as AIDS patients; C. gattii causes disseminated infections even in healthy hosts. To identify the possible molecular mechanisms underlying this difference in virulence, we investigated the survival and histopathology of lung tissue in wild-type and CD4-depleted mice infected with C.
View Article and Find Full Text PDFA 32-year-old man on peritoneal dialysis (PD) was hospitalized for seven days due to fever. A diagnosis of yeast-like fungal peritonitis was made by Gram staining. The patient was started on intravenous micafungin and oral fluconazole therapy following removal of the PD catheter.
View Article and Find Full Text PDFWe report a patient with severe invasive pulmonary fungal infection caused by Aspergilllus lentulus, which was identified by genetic analysis, following liver transplantation. The patient was initially suspected to have Aspergilllus fumigatus infection, but worsened clinically despite antifungal therapy appropriate for that species. The patient survived after accurate diagnosis, and detailed drug susceptibility testing led to adequate therapy, demonstrating the importance of performing these investigations for severely immunocompromised patients, including organ transplant recipients.
View Article and Find Full Text PDFCryptococcosis due to a highly virulent fungus, Cryptococcus gattii, emerged as an infectious disease on Vancouver Island in Canada and surrounding areas in 1999, causing deaths among immunocompetent individuals. Previous studies indicated that C. gattii strain R265 isolated from the Canadian outbreak had immune avoidance or immune suppression capabilities.
View Article and Find Full Text PDFTo obtain therapeutically effective new antibiotics, we first searched for bacterial culture supernatants with antimicrobial activity in vitro and then performed a secondary screening using the silkworm infection model. Through further purification of the in vivo activity, we obtained a compound with a previously uncharacterized structure and named it 'lysocin E'. Lysocin E interacted with menaquinone in the bacterial membrane to achieve its potent bactericidal activity, a mode of action distinct from that of any other known antibiotic, indicating that lysocin E comprises a new class of antibiotic.
View Article and Find Full Text PDFFluconazole (FLCZ) is a first-line drug for treating Candida albicans infections, but clinical failure due to reduced sensitivity is a growing concern. Our previous study suggested that certain drug combinations pose a particular challenge in potently reducing FLCZ's anti-C. albicans activity, and cyclooxygenase inhibitors formed the major group of these attenuating drugs in combination with FLCZ.
View Article and Find Full Text PDFEffects of chlorination on the toxicity of wastewater effluents treated by activated sludge (AS) and submerged membrane bioreactor (S-MBRB) systems to HepG2 human hepatoblastoma cells were investigated. In addition to the cytotoxicity and genotoxicity assays, the DNA microarray-based transcriptome analysis was performed to evaluate the change in types of biological impacts on HepG2 cells of the effluents by chlorination. Effluent organic matter (EfOM) and disinfection by-products (DBPs) were also characterized by using Fourier transform mass spectrometry (FT-MS).
View Article and Find Full Text PDFMost antibiotics obtained by in vitro screening with antibacterial activity have inappropriate properties as medicines due to their toxicity and pharmacodynamics in animal bodies. Thus, evaluation of the therapeutic effects of these samples using animal models is essential in the crude stage. Mammals are not suitable for therapeutic evaluation of a large number of samples due to high costs and ethical issues.
View Article and Find Full Text PDFBackground: We aimed to study the effects of intra-articular injection of jellyfish mucin (qniumucin) on articular cartilage degeneration in a model of osteoarthritis (OA) created in rabbit knees by resection of the anterior cruciate ligament. Qniumucin was extracted from Aurelia aurita (moon jellyfish) and Stomolophus nomurai (Nomura's jellyfish) and purified by ion exchange chromatography. The OA model used 36 knees in 18 Japanese white rabbits.
View Article and Find Full Text PDFThe structure of O-glycan in qniumucin (Q-mucin), which is a novel mucin extracted from jellyfish, was analyzed by a combination of NMR and ESI-MS/MS. A previously unidentified monosaccharide involved in the glycan chains was determined to be N-acetylgalactosamine (GalNAc) substituted by 2-aminoethylphosphonate (AEP) at the C-6. The O-glycans in Q-mucin from Aurelia aurita were proved to be mainly composed of three monosaccharides: GalNAc, AEP-(O-->6)-GalNAc, and P-6-GalNAc.
View Article and Find Full Text PDFAn aluminium-tolerant bacterium, strain AL46(T), was isolated from a waterweed, Panicum repens, grown in a highly acidic swamp (pH 3) at an actual acid sulfate soil area of Vietnam. Cells were Gram-negative, aerobic, non-spore-forming, non-motile rods (0.3 microm wide and 1.
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