Nature of excited Ξ\Xi baryons with threshold effects

Spectroscopy of excited baryons with strangeness $S=-2$ is stimulated by recent experimental developments. Here we focus on the $\Xi(1620)$ which locates close to the $\bar{K}\Lambda$ threshold. To take into account the threshold effects, we construct the coupled-channels meson-baryon scattering amplitude where the $\Xi(1620)$ appears as a resonance. We demonstrate that the $\bar{K}\Lambda$ threshold effects distort the peak of the $\Xi(1620)$ resonance from the simple Breit-Wigner distribution.Comment: 4 pages, Proceedings of the 14th International Conference on Hypernuclear and Strange Particle Physics (HYP2022), 27 June to 1 July 2022. v2: modified the right panel of the figure

Analysis of Ξ(1620)\Xi(1620) resonance with chiral unitary approach

Recently, the $\Xi(1620)$ resonance has attracted much attention, thanks to detailed experimental data by the Belle and ALICE collaborations. This experimental progress has prepared us to conduct theoretical analyses based on experimental data. In this study, we analyze the $\Xi(1620)$ resonance using the chiral unitary model and discuss the properties of the $\Xi(1620)$ resonance and the $K^-\Lambda$ scattering length.Comment: 4 pages, 2 figures, Proceedings of 17th International Workshop on Meson Physics (MESON2023), 22nd - 27th June, 202

Molecular characterization of clinical isolate of Vibrio cholera isolated from outbreaks cases in Malaysia

A total of 32 clinical strains of Vibrio cholerae, including members of the 01 and 0139 serogroup were collected from Klang, Selangor; Penang Island; Samarahan, Sarawak and Miri, Sarawak in Malaysia. In general, all the isolates except the 0139 serotype expressed low resistance to all the antibiotics tested with their Multiple Antibiotic Resistance (MAR) indices ranged from 0.10 to 0.48. The presence of ctx gene that encoded the cholera toxin was confirmed in all these clinical isolates by polymerase chain reaction. The results from the RAPD-PCR were analyzed using the RAPDistance software (Version 1.04). From the dendrogram generated, two main groups were observed which were subdivided into two clusters each. The Selangor's isolates and the 0139 Penang's isolates formed one group whereas the Samarahan, Sarawak isolates and the Miri, Sarawak isolates made up the other group, thus delineating their different sources of origin based on their geographical location

ヒストンバリアントH2A.Z-2の交換反応による損傷クロマチンの構造変換

内容の要旨 , 審査の要旨広島大学(Hiroshima University)博士(医学)Doctor of Philosophy in Medical Sciencedoctora

Human health significance of vibrios from the aquatic environment

For the enrichment and enumeration of Vibrio fluvialis, a broth medium was designed by modifying alkaline peptone (AP) medium. This new V. fluvialis enrichment medium (FEM) was shown to be more effective than AP medium in field samplings where a total of 177 samples (estuarine waters and sediment, sewage, and crabs) were processed over a 14 month period. FEM was particularly superior to AP for water and sewage with low salinities (<6%0). V. vulnificus was shown to have a species-specific antigen by analyzing sonicated whole-cell antigens with two-dimensional immunoelectrophoresis. The antigen (designated as VVA) was purified by various protein chemistry techniques, and specific antiserum to VVA was prepared. Using anti-VVA serum, a simple and rapid microimmunodiffusion method was designed which allowed the specific identification of V. vulnificus in as early as 10 hrs after preparing a bacterial cell lysate from a single colony. suckling mouse assay was utilized to examine enteropathogenicity, i.e., potential to cause diarrhea, of environmental and clinical isolates of 0-1 and non 0-1 V. cholerae, V. mimicus, and V. fluvialis. Cultures from both environmental and clinical origins induced intestinal fluid accumulation (FA) in 3-day-old mice at 4 hr postinoculation followed by diarrheal feces and high mortality. The virulence-associated factor(s) that caused FA were different from cholera toxin (CT) in terms of kinetics of FA and serological behavior, but were correlated with extracellular cytotoxic factors active against Y-1 mouse adrenal tissue cultures. Furthermore, all clinical isolates of non 0-1 V. cholerae, V. mimicus, and V. fluvialis, when grown in brain heart infusion broth supplemented with 0.5% sodium chloride, were found to produce a new extracellular heat-labile enterotoxin which induced significant FA in 3-day-old mice and was distinct from previously reported enterotoxins including CT. Most of the environmental isolates, however, did not produce the newly discovered enterotoxin

Molecular characterisation of Vibrio parahaemolyticus carrying tdh and trh genes using ERIC-, RAPD- and BOX-PCR on local Malaysia bloody clam and Lala

Molecular typing methods have been widely applied for many purposes. In this study, such methods were adopted as DNA fingerprinting tools to determine the origin and divergence of virulent Vibrio parahaemolyticus strains found in local seafood. Although not all strain carry virulent tdh and trh gene, increasing prevalence demands an effective fingerprinting scheme which can constantly monitor and trace the sources of such emerging food pathogens. By using ERIC-, RAPD-, and BOX-PCR methods, 33 Vibrio parahaemolyticus isolates from local Malaysia bloody clam (Anadara granosa) and Lala (Orbicularia orbiculata) with confirmed presence of tdh and trh gene were characterised, followed by determination of clonal relatedness among virulent strains using cluster analysis and discriminatory index. This study also involved application of Immunomagnetic Separation (IMS) Method which significantly improved the specificity of strain isolation. Cluster analysis using Unweighted Pair Group Mathematical Averaging (UPGMA) and Dice Coefficient shown clustering according to isolation food source, IMS level and haemolysin gene possessed. Nevertheless, different DNA fingerprinting methods generated different clustering at different similarity cut-off percentage, regardless as individual or as composite dendrograms. ERIC- and RAPD-PCR composite fingerprinting relatively shown the highest discriminatory index at following similarity cut- off percentage: 0.68 at 50%; 0.83 at 65%; and 0.93 at 75%. Discriminatory power increased with similarity cut-off percentage. However, result also suggested that BOX-PCR might be an effective fingerprinting tool, as it generated three clusters with no single-colony isolate at 70% similarity cut-off. This study not only achieved its objective to determine clonal relatedness among virulent strains from local seafood via characterisation, but also speculated the best possible combination of molecular typing methods to effectively do s

Efficiency of four Malaysian commercial disinfectants on removing Listeria monocytogenes biofilm

Listeria monocytogenes(L. monocytogenes) is a gram positive food-borne pathogen that is able to form biofilm on food factory surfaces. Formation of biofilm makes the bacteria much more resistance to environmental stresses such as disinfectant. The extracellular polymeric matrix (biofilm structure) which is mostly comprised of sticky extracellular polysaccharides (EPS) and proteins can protect bacteria in a harsh condition. The efficiency of four disinfectants on removing L. monocytogenes biofilm was investigated. Five concentration levels (100, 50,25, 12.5, and 6.25%) of disinfectants were tested. In the microtitre assay, the optical density at 595 nm CV-OD 595 value, was used to measure the amount of remained biofilm after 24 h. Results showed that disinfectants did not have significant effect on removing L. monocytogenes biofilm. Formation of L. monocytogenes biofilm significantly decreased the efficiency of disinfectants. Biofilm produced by strain number 9 showed higher resistance to disinfectant. Low concentrations (<50%) of disinfectants did not show significant effect on removing L. monocytogenes biofilm

養殖ヨーロッパウナギ(Anguilla anguilla)から分離されたVibrio anguillarum

Vibrio anguillarumはヨーロッパにおいて海水中および汽水中のウナギに鰭赤病を起こすものとして古くから知られている。1969年以来，ニホンウナギ(Anguilla japonica)の種苗不足を補うためヨーロッパウナギ(A. anguilla)のシラスが大量に輸入され，日本各地で養殖されているが，我が国においてはヨーロッパウナギでのV. anguillarum感染症の発生は現在まで報告されていない。 1975年4月末，徳島県下のやや塩分を含む養殖池において，前年から赤点病(Pseudomonas anguilliseptica感染症)が発生していた魚群について検査したところ，P. anguillisepticaとともにV. anguillarumが分離され，ヨーロッパウナギにおける本菌感染症が我が国でも確認された。 しかしながら，その感染率は比較的低く，また本病による大量斃死も認められなかった。これはヨーロッパウナギがニホンウナギと同様，V. anguillarumに対してある程度抵抗性を有しているためと考えられた