bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Silkworm Larvae Plasma Test for Detecting Peptidoglycan in Cerebrospinal Fluid Is Useful for the Diagnosis of Bacterial Meningitis
Authors: Inada Katsuya , Takahashi Kiyomi , Ichinohe Sadato , Suda Hidetoshi , Tsuchiya Masakazu , Takahashi Junkichi , Matsuura Shuji , Kasai Takeshi , Yoshida Masao , Endo Shigeatsu , Sato Shigehiro 
Published: November 2013

AbstractThe silkworm larvae plasma (SLP) test has been established based on a cascade reaction triggered by either peptidoglycan or (1, 3)‐β‐D‐glucan to produce melanin. We applied this test to the diagnosis of bacterial meningitis. Cerebrospinal fluid (CSF) obtained from patients with bacterial meningitis due to gram‐positive bacteria, gram‐negative bacteria, or fungi, showed positive reactions to the test. In contrast, CSF from patients with viral meningitis or noninfectious illnesses gave negative reactions. Therefore, this test seems to be useful for diagnosis of bacterial and fungal meningitis. When this test was used together with two types of limulus tests, an endotoxin‐specific test, and a conventional test, meningitis was further characterized as gram‐positive, gram‐negative or fungal meningitis. The SLP test requires a computerized instrument for quantitative colorimetric measurement. A qualitative alternative of this test also can be accomplished by visually observing the darkening color. Thus, this method can be applied for simple and rapid diagnosis of meningitis.
Two Different Mechanisms Are Involved in the Extremely High‐Level Benzalkonium Chloride Resistance of a Pseudomonas fluorescens Strain
Authors: Nagai Katsuhiro , Murata Takahiro , Ohta Shin , Zenda Hiroshi , Ohnishi Makoto , Hayashi Tetsuya 
Published: November 2013

AbstractA Pseudomonas fluorescens strain, PFRB, which we previously isolated as a contaminant in a batch of benzalkonium chloride (BAC) stock solution, exhibits high‐level resistance, not only to BAC, but also to other cationic surfactants belonging to disinfectants classified as quaternary ammonium compounds (QACs). In this study, we analyzed the resistance mechanism of the strain to BAC and other disinfectants. We obtained results suggesting that two different mechanisms, reduced adsorption of BAC to the cell surface and an energy‐dependent mechanism which is most probably an efflux system, were implicated in the high‐level resistance to BAC. Reduced adsorption of BAC is likely due to the decreased negative cell surface charge of the strain. The putative efflux system seems to be unique in that it excretes only a certain range of cationic membrane‐acting disinfectants belonging to QACs.
Peptidase Activity of Dipeptidyl Aminopeptidase IV Produced by Porphyromonas gingivalis Is Important but Not Sufficient for Virulence
Authors: Kumagai Yumi , Yajima Ayako , Konishi Kiyoshi 
Published: November 2013

AbstractPorphyromonas gingivalis is a pathogen associated with adult periodontitis, which is a chronic inflammatory disease characterized by breakdown of the periodontal tissue. Dipeptidyl aminopeptidase IV (DPPIV) produced by P. gingivalis has been considered to be a potential virulence factor based on the finding that the virulence was reduced by disruption of the gene (dpp) coding for DPPIV. In the present study, we constructed a shuttle vector that is mobilized from Escherichia coli to P. gingivalis and is maintained stably in both bacteria, and we showed that the virulence was restored by introducing the cloned wild‐type dpp gene into the null mutant of P. gingivalis using our vector system. To assess the implications of the peptidase activity in the virulence, mutant DPPIV with the catalytic Ser mutagenized to Ala (DPPSA) was produced. The P. gingivalis strain expressing DPPSA exhibited an intermediate virulence between the strain expressing wild‐type DPPIV and the strain harboring a vector. From these results, it is suggested that peptidase activity is very important but not sufficient for virulence.
Rate of Helicobacter pylori Infection in Children and Clonality of Taiwan Strains
Authors: Chu Chi shih , Yu Yu‐Jen , Kong Man Shan , Ou Jonathan T. 
Published: November 2013

AbstractThe infection rate of Helicobacter pylori in children from <1 to 17 years old was investigated. Three techniques, namely culture, CLO test, and PCR, were employed to check the presence or absence of the organism in the antrum of the stomach. Several PCR positives without viable cultures were observed in babies of less than one year old. On the other hand, only two viable cultures were obtained from toddlers of less than two years old. The percentage of positive cultures steadily increased from 8% (3 of 42 cases) in the 0–4 years old age group to 32% (32 of 99 cases) in the 13–17 years old age group. A steady increase also was observed in the result of the CLO test. In PCR, the percentage of positives was greatly higher than that seen with the culture or CLO test. The rate of PCR positives also showed an increase with age but of a much slower rate. The overall infection rate in 295 children was 22% (64 of 295 cases) positive with culture and 76% (225 of 295 cases) with PCR, in contrast to 85% (40 of 49 cases) and 92% (43 of 47 cases), respectively, in adults. The urease activity of the H. pylori derived from children was much lower than that derived from adults (P<0.001). Taken together, these results suggest that a child might be repeatedly infected and some infecting strains eventually might obtain a steady infection, perhaps by a strain of higher virulence such as higher urease activity. The base variations in the nucleotide sequences did not correlate to the varied urease activities or to the age of the child. The sequences, however, indicated that there were two types of strains. The strains in Taiwan appeared to be derived from the French type strain and not the English type strain. The amino acid sequences of the ureA and the phylogenetic relationship of the 29 strains indicated that the strains in Taiwan are rapidly evolving into a unique clone.
Morphological Properties of a Human Intestinal Spirochete First Isolated from a Patient with Diarrhea in Japan
Authors: Tasu Chollada , Nakamura Shin‐ichi , Tazawa Hideki , Hara Hiromichi , Adachi Yoshikazu 
Published: November 2013

AbstractA human intestinal spirochete isolated from a rectal biopsy specimen was morphologically characterized. The isolate was comma‐shaped, 3–6 μm in length, 0.2 μm in diameter and had tapered ends. The surface layer, external to the outer envelope, was amorphous. Four string‐like periplasmic flagella with a diameter of 20 nm were presented at each end of the SDS‐treated cells. Thin sections of the bacterial cell revealed a high‐density cytoplasmic membrane and flagella in the periplasmic space between the cytoplasmic membrane and the outer envelope. Three segments of equal length were observed in some of the cells, while other cells were bi‐segmented and more frequently observed.
Induction of Protective Immunity by Primed B‐1 Cells in Toxoplasma gondii‐Infected B Cell‐Deficient Mice
Authors: Chen Mei , Mun Hye‐Seong , Piao Lian‐Xun , Aosai Fumie , Norose Kazumi , Mohamed Rabie M. , Belal Usama S. , Fang Hao , Ahmed Azza K. , Kang Hyun‐Kyu , Matsuzaki Goro , Kitamura Daisuke , Yano Akihiko 
Published: November 2013

AbstractWe examined the role of B‐1 cells in protection against Toxoplasma gondii infection using B cell‐deficient mice (μMT mice). We found that primed but not naïve B‐1 cells from wild‐type C57BL/6 mice protected B cell‐deficient recipients from challenge infection. All μMT mice transferred with primed B‐1 cells survived more than 5 months after T. gondii infection, whereas 100% of μMT mice transferred with naïve B‐1 cells succumbed by 18 days after infection. Additionally, high expression of both T help (Th) 1‐ and Th2‐type cytokines and a high level of nitric oxide production were observed in T. gondii‐infected μMT mice transferred with primed B‐1 cells. Thus, it was clearly demonstrated that B‐1 cells play an important role in host protection against T. gondii infection in μMT mice.
Moenomycin‐Resistance Is Associated with Vancomycin‐Intermediate Susceptibility in Staphylococcus aureus
Authors: Nishi Hiromi , Komatsuzawa Hitoshi , Yamada Sakuo , Fujiwara Tamaki , Ohara Masaru , Ohta Kouji , Sugiyama Masaru , Ishikawa Takenori , Sugai Motoyuki 
Published: November 2013

AbstractWe have previously isolated a vancomycin‐intermediate susceptibility mutant from methicillin‐resistant Staphylococcus aureus (MRSA) strain COL, and demonstrated the increased glycan‐chain length and the decreased moenomycin‐susceptibility. To further investigate the relationship between the resistance to vancomycin and to moenomycin, we isolated moenomycin‐resistant mutants (4–16 fold higher compared to the parent) from 5 MRSA and 2 methicillin‐sensitive S. aureus (MSSA) strains. The MRSA mutants showed a decreased susceptibility to vancomycin (2–4 fold), teicoplanin (2–4 fold) and an increased susceptibility to methicillin (2–8 fold). MSSA strains also showed similar results with those of MRSA strains except that there was no alteration of methicillin susceptibility. Among the mutants, three mutants including two MRSA mutants and one MSSA mutant were analyzed by electron microscopy, and they showed thickened cell walls compared to those of the parents. The glycan‐chain length of the peptidoglycan of the mutant was shown to be slightly longer than that of the parent, but the muropeptide profile was very similar. The expression levels of all PBPs were similar to those of the parent. Furthermore, the nucleotide sequences of sgtA, sgtB and pbp2 in the mutant were identical to those of the parent. These results indicate that the moenomycin‐resistance is closely associated with vancomycin‐intermediate susceptibility in S. aureus.
Serological Identification of Endothelial Antigens Predominantly Recognized in Kawasaki Disease Patients by Recombinant Expression Cloning
Authors: Kaneko Miho , Ono Toshiro , Matsubara Tomoyo , Yamamoto Yukiyo , Ikeda Hitoshi , Yoshiki Takashi , Furukawa Susumu , Nakayama Eiichi 
Published: November 2013

AbstractWe showed IgG immune response against endothelial antigens in sera obtained from convalescent Kawasaki disease (KD) patients after recovery from the disease during the follow‐up period using serological analysis of recombinant cDNA expression library (SEREX) methodology. We identified 46 antigens represented by 69 clones by immunoscreening of a cDNA expression library from tumor necrosis factor‐α (TNFα) treated human umbilical vein endothelial cells (HUVEC) with sera from 4 KD patients. They included ubiquitin pathway proteins, transcriptional factors, signal transduction molecules, metabolic enzymes, cytoskeletal proteins, an adhesion molecule, and a cell cycle protein. By serological survey using phage plaque assay, sera from 5 non‐KD patients were rarely reactive with the antigens. Among the antigens, tropomyosin was most frequently isolated (18 of 69 clones). Seventeen of the 18 clones were identified using KD3 serum. The second most frequently isolated antigen was also a cytoskeletal protein, called T‐plastin (3 of 69 clones).
On the Cyto‐Toxicity Caused by Quantum Dots
Authors: Shiohara Amane , Hoshino Akiyoshi , Hanaki Ken‐ichi , Suzuki Kazuo , Yamamoto Kenji 
Published: November 2013

AbstractQuantum dots (QDs) such as CdSe QDs have been introduced as new fluorophores. The QDs conjugated with antibody are starting to be widely used for immunostaining. However there is still not sufficient analysis of the toxicity of QDs in the literature. Therefore we evaluated the cell damage caused by the quantum dots for biological applications. We performed cell viability assay to determine the difference in cell damage depending on the sizes and colors of mercapto‐undecanoic acid (MUA) QDs and the cell types. The results showed that the cell viability decreased with increasing concentration of MUA‐QDs. But in the case of Vero cell (African green monkey's kidney cell) with red fluorescence QD (QD640), the cell damage was less than for the others. Furthermore through the flow cytometry assay we found that this cell damage caused by MUA‐QD turned out to be cell death after 4‐6‐hr incubation. From the two assays described above, we found that there is a range of concentration of MUA‐QDs where the cell viability decreased without cell death occurring and thus we conclude that attention should be given when MUA‐QDs are applied to living organisms even in low concentrations.
Molecular Characterization of Dextranase from Streptococcus rattus
Authors: Igarashi Takeshi , Morisaki Hirobumi , Goto Nobuichi 
Published: November 2013

AbstractThe complete nucleotide sequence of the dextranase gene of Streptococcus rattus ATCC19645 was determined. An open reading frame of the dextranase gene was 2,760 bp long and encoded a dextranase protein consisting of 920 amino acids with a molecular weight of 100,163 Da and an isoelectric point of 4.67. The S. rattus dextranase purified from recombinant Escherichia coli cells showed dextran‐hydrolyzing activity with optimal pH (5.0) and temperature (40 C) similar to those of dextranases from Streptococcus mutans and Streptococcus sobrinus. The deduced amino acid sequence of the S. rattus dextranase revealed that the dextranase molecule consists of two variable regions and a conserved region. The variable regions contained an N‐terminal signal peptide and a C‐terminal cell wall sorting signal; the conserved region contained two functional domains, catalytic and dextran‐binding sites. This structural feature of the S. rattus dextranase is quite similar to that of other cariogenic species such as S. mutans, S. sobrinus, and Streptococcus downei.
Down‐Regulation of gp96 by Orientia tsutsugamushi
Authors: Cho Nam‐Hyuk , Choi Cheol‐Young , Seong Seung‐Yong 
Published: November 2013

Abstractgp96 plays a central role in innate as well as acquired immunity, maturation and chemotaxis of dendritic cells, Ab production, and cross‐priming, and is a peptide acceptor in endoplasmic reticulum and an accessory to peptide loading of MHC class I molecules. The remarkable conservation of essential immunological properties of gp96 suggests their important roles during the evolution of the immune system. Considering their importance in immunity, immune evasion mechanisms of pathogens by modulating gp96 expression have been speculated. By differential display PCR, we observed that obligate intracellular bacteria, Orientia tsutsugamushi, inhibit gp96 expression of a macrophage cell line, J774A.1. Not only gp96 transcripts but also protein was lower than for null‐infected cells. The down‐regulation was also consistent in an endothelial cell line, HMEC‐1, and in murine peritoneal cells. These data support the idea that gp96 may be one of the target molecules for the immune evasion by intracellular bacteria.
Virulence Properties of Rough and Smooth Strains of Vibrio cholerae O1
Authors: Islam Mohammad Sirajul , Ahsan Sunjukta , Khan Sirajul Islam , Ahmed Qazi Shafi , Rashid Mohammad Harunur , Islam Khan M. Nasirul , Sack Richard Bradley 
Published: November 2013

AbstractA comparative study was carried out to see the differences in pathogenicity of rough and smooth strains. A total of 10 strains including 5 each of rough and smooth strains of Vibrio cholerae O1 were tested and found positive for toxin production by enzyme‐linked immunosorbent assay (ELISA) in Richardson's and AKI media. All the smooth and rough strains, except one, showed a titre of 1:10 and 1:100 in Richardson's and AKI media, respectively. Both types of strains produced enterotoxin in rabbit ileal loop (RIL). The differences in multiplication abilities of smooth and rough strains in RIL were statistically significant (P<0.05). However, these differences in multiplying abilities did not influence the adherence potential or enterotoxin production as there was no significant difference (P>0.05) between these properties. This study demonstrated that the rough strains are equally pathogenic and as important as smooth strains.
Comparison among Fecal Secondary Bile Acid Levels, Fecal Microbiota and Clostridium scindens Cell Numbers in Japanese
Authors: Kitahara Maki , Sakata Shinji , Sakamoto Mitsuo , Benno Yoshimi 
Published: November 2013

AbstractBile acid 7α‐dehydroxylation by intestinal bacteria, which converts cholic acid and chenodeoxycholic acid to deoxycholic acid (DCA) and lithocholic acid (LCA), respectively, is an important function in the human intestine. Clostridium scindens is one of the most important bacterial species for bile acid 7α‐dehydroxylation because C. scindens has high levels of bile acid 7α‐dehydroxylating activity. We quantified C. scindens and secondary bile acids, DCA and LCA, in fecal samples from 40 healthy Japanese and investigated their correlation. Moreover, we used terminal restriction fragment length polymorphism (T‐RFLP) analysis to investigate the effect of fecal microbiota on secondary bile acid levels. There was no correlation between C. scindens and secondary bile acid in fecal samples. On the other hand, T‐RFLP analysis demonstrated that fecal microbiota associated with high levels of DCA were different from those associated with low levels of DCA, and furthermore that fecal microbiota in the elderly (over 72 years) were significantly different from those in younger adults (under 55 years). These results suggest that intestinal microbiota have a stronger effect on DCA level than does the number of C. scindens cells.
Identification and Characterization of Two Contiguous Operons Required for Aerobactin Transport and Biosynthesis in Vibrio mimicus
Authors: Moon Yong‐Hwa , Tanabe Tomotaka , Funahashi Tatsuya , Shiuchi Kei‐ichi , Nakao Hiroshi , Yamamoto Shigeo 
Published: November 2013

AbstractIn response to iron deprivation, Vibrio mimicus produces aerobactin as a major siderophore. Application of the Fur titration assay to a V. mimicus genomic DNA library followed by further cloning of the surrounding regions led to the identification of two adjacent, iron‐regulated operons. One contains three genes encoding homologs of the Escherichia coli FhuCDB and the other, five genes encoding homologs of the E. coli IucABCD IutA. Construction of the V. mimicus polar disruptants in the respective operons allowed us to confirm their functions. The genetic arrangement of the aerobactin‐mediated iron acquisition system in V. mimicus is unique in that the aerobactin operon (iucABCD iutA) is contiguous to the operon (matCDB) encoding components of an ATP‐binding cassette transport system for ferric aerobactin. This is the first report demonstrating that aerobactin transport and biosynthesis genes are present in a species outside the family Enterobacteriaceae.
Association of Rabies Virus Nominal Phosphoprotein (P) with Viral Nucleocapsid (NC) Is Enhanced by Phosphorylation of the Viral Nucleoprotein (N)
Authors: Toriumi Harufusa , Kawai Akihiko 
Published: November 2013

AbstractWe investigated possible role(s) of N protein phosphorylation in the rabies virus replication process. A large amount of P proteins are associated with the viral nucleocapsid (NC) in the infected cell, the amount which was greatly decreased by phosphatase‐treatment of the isolated NC, indicating that the phosphate group of N and/or P proteins is essential for their stable association with the NC. Immunoprecipitation studies were performed on the coexpressed normal N or phosphorylation deficient N(S389A) and P proteins, demonstrating that the P protein associated with phosphorylation‐deficient NC‐like structures was much less in amount than that associated with the wild type NC. Similar results were also obtained with a mutant P protein, PΔN19, which lacked the N‐terminal 19 amino acids and was capable of binding to the NC‐like structures but incapable of forming the RNA‐free N‐P complexes. Immunoprecipitation studies with mAb #402‐13 further suggested that the NC‐specific linear 402–13 epitope was exposed even on the P proteins which were associated with the phosphorylation‐deficient NC‐like structures, but such association was very weak as demonstrated by greatly decreased amounts of coprecipitated NC‐like structures. From these results, we assume that the phosphorylation of N protein enhances the association between the 402–13 epitope‐positive P protein and the NC probably by stabilizing such P‐NC binding.
Isolation and Phylogenetic Analysis of Arcobacter Spp. in Ground Chicken Meat and Environmental Water in Japan and Thailand
Authors: Morita Yukio , Maruyama Soichi , Kabeya Hidenori , Boonmar Sumalee , Nimsuphan Burin , Nagai Akira , Kozawa Kunihisa , Nakajima Takashi , Mikami Takeshi , Kimura Hirokazu 
Published: November 2013

AbstractPrevalence of Arcobacter spp. in chicken meat samples and environmental water samples in Japan and Thailand was investigated. Arcobacter was isolated from 48% of chicken meat samples (20/41) and 23% of river water samples (4/17) from Japan, and 100% of chicken meat samples (10/10) and 100% of canal water samples (7/7) from Thailand. A. butzleri was among the species isolated from all positive samples. About 10% genetic diversity was seen in the rpoB‐rpoC in Arcobacters, and phylogenetic trees were divided into two clusters. In both countries, the results suggested that chicken and environmental water were highly contaminated with a genetically diverse population of Arcobacter.
Fluconazole‐Resistant Pathogens Candida inconspicua and C. norvegensis: DNA Sequence Diversity of the rRNA Intergenic Spacer Region, Antifungal Drug Susceptibility, and Extracellular Enzyme Production
Authors: Sugita Takashi , Takeo Kanji , Ohkusu Misako , Virtudazo Eric , Takashima Masako , Asako Emi , Ohshima Fumiko , Harada Satoshi , Yanaka Chikako , Nishikawa Akemi , Majoros Laszlo , Sipiczki Matthias 
Published: November 2013

AbstractThe opportunistic fungal pathogens Candida inconspicua and C. norvegensis are very rarely isolated from patients and are resistant to fluconazole. We collected 38 strains of the two microorganisms isolated from Europe and Japan, and compared the polymorphism of the rRNA intergenic spacer (IGS) and internal transcribed spacer (ITS) regions, antifungal drug susceptibility, and extracellular enzyme production as a potential virulence factor. While the IGS sequences of C. norvegensis were not very divergent (more than 96.7% sequence similarity among the strains), those of C. inconspicua showed remarkable diversity, and were divided into four genotypes with three subtypes. In the ITS region, no variation was found in either species. Since the sequence similarity of the two species is approximately 70% at the ITS region, they are closely related phylogenetically. Fluconazole resistance was reconfirmed for the two microorganisms but they were susceptible to micafungin and amphotericin B. No strain of either species secreted aspartyl proteinase or phospholipase B. These results provide basal information for accurate identification, which is of benefit to global molecular epidemiological studies and facilitates our understanding of the medical mycological characteristics of C. inconspicua and C. norvegensis.
Effects of Endocytosis Inhibitory Drugs on Rubella Virus Entry into VeroE6 Cells
Authors: Kee Sun‐Ho , Cho Eun‐Jin , Song Jin‐Won , Park Kwang Sook , Baek Luck Ju , Song Ki‐Joon 
Published: November 2013

AbstractIt has been suggested that infectious entry of rubella virus (RV) is conducted by receptor mediated endocytosis. To explore the cellular entry mechanism of RV, inhibitory effects of drugs affecting various endocytic pathways on RV entry into VeroE6 cells were analyzed. Results showed that RV infectious entry into VeroE6 cells is mediated by clathrin‐dependent endocytosis and not by caveolae‐mediated endocytosis. Moreover, chemical inhibition of macropinocytosis such as treatments of amiloride, actin and microtubule‐disrupting drug significantly reduced RV infection. Considering that macropinocytosis is inducible endocytosis by cellular stimulations, clathrin‐mediated endocytosis is likely to be a major route of RV infectious entry.