565 research outputs found
Nature of excited baryons with threshold effects
Spectroscopy of excited baryons with strangeness is stimulated by
recent experimental developments. Here we focus on the which
locates close to the threshold. To take into account the
threshold effects, we construct the coupled-channels meson-baryon scattering
amplitude where the appears as a resonance. We demonstrate that the
threshold effects distort the peak of the
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 resonance with chiral unitary approach
Recently, the 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 resonance using
the chiral unitary model and discuss the properties of the
resonance and the 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
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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
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