Prevalence and Genetic Properties of Salmonella enterica Serovar Typhimurium Definitive Phage Type 104 Isolated from Rattus norvegicus and Rattus rattus House Rats in Yokohama City, Japan

Salmonella enterica serovar Typhimurium was isolated from the intestinal contents of Rattus rattus and Rattus norvegicus house rats captured at two buildings, designated buildings J and YS, in Yokohama City, Japan. From October 1997 to September 1998, 52 of 339 (15.3%) house rats were found to carry Salmonella serovar Typhimurium definitive phage type 104 (DT104). In building J, 26 of 161 (16.1%) house rats carried DT104 over the 1-year study period, compared to 26 of 178 (14.6%) rats in building YS. The isolation rates of DT104 from R. rattus and R. norvegicus were similar in the two buildings. Most DT104 strains from building J (24 of 26) showed resistance to ampicillin, chloramphenicol, streptomycin, sulfisoxazole, and tetracycline and contained both the 1.0- and 1.2-kbp integrons, carrying genes pse1, pasppflo-like, aadA2, sulI, and tet(G). All DT104 strains from building YS were resistant to ampicillin and sulfisoxazole, and had the 1.2-kbp integron carrying pse1 and sulI. Cluster analysis of pulsed-field gel electrophoresis patterns of BlnI-digested DT104 DNAs showed that 22 of 26 DT104 strains from building J and 24 of 26 strains from building YS could be grouped into separate clusters each specific for the building origin. These results indicated that DT104 strains were prevalent in house rat colonies in each building and suggest that house rats may play an important role in the epidemiology of DT104.     

5-aminolaevulinic acid (ALA), enhances heme oxygenase (HO)-1 expression and attenuates tubulointerstitial fibrosis and renal apoptosis in chronic cyclosporine nephropathy

Background

Cyclosporine-A (CsA) is an immunosuppressant indicated for various immunological diseases; however, it can induce chronic kidney injury. Oxidative stress and apoptosis play a crucial role in CsA-induced nephrotoxicity. The present study evaluated the protective effect of combining 5-aminolaevulinic acid with iron (5-ALA/SFC), a precursor of heme synthesis, to enhance HO-1 activity against CsA-induced chronic nephrotoxicity.

Prepubertal onset of slipped capital femoral epiphysis associated with hypothyroidism: a case report and literature review

Background

Slipped capital femoral epiphysis (SCFE) is a common hip disorder characterized by displacement of the capital femoral epiphysis from the metaphysic through the femoral epiphyseal plate. SCFE usually occurs during puberty, with obesity a common risk factor. We experienced a rare case of SCFE associated with hypothyroidism in a prepubescent patient who was not obese.

Case presentation

The patient was an 8-year-old boy suffering from bilateral SCFE with hypothyroidism. The patient’s growth had started to slow at 4 years of age, and at 8 years he was of short stature. During his evaluation for SCFE management, primary hypothyroidism was diagnosed due to the presence of anti-thyroid peroxidase and anti-thyroglobulin antibodies. After the patient was treated for hypothyroidism, which improved his thyroid function, surgery was performed for bilateral SCFE.

Conclusions

Among the 42 patients with SCFE associated with hypothyroidism in the literature, most SCFE occurred during puberty or in adults with delayed epiphyseal closure. Only two patients (4.8%), including the present patient, were ≤9 years old. Although being overweight or obese is common for patients with SCFE associated with hypothyroidism (76.0%), it was not observed in the present case. Persistent hypothyroidism, however, may be a risk factor for SCFE even before puberty and without obesity.

     

Calculation of self-diffusion coefficients of the [BMIM][TFSA]/water system by molecular dynamics simulation

We performed a molecular dynamics simulation to calculate the self-diffusion coefficients of 1-Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and water in a water–ionic liquid mixture. We then compared the simulated self-diffusion coefficients of cation, anion and water molecules with experimental data and with simulated data from the literature. Although the simulation overestimated the self-diffusion coefficients of ions, the simulated results qualitatively reproduced the enhancement of the self-diffusion coefficients of water as the water molar fraction increased. We also calculated the radial distribution functions to investigate the solution structure, i.e. the clustering of water molecules. The clustering of water in ionic liquid was found to play an important role in the enhancement of the diffusion of water molecules in the ionic liquid.     

Fission yeast Stn1 maintains stability of repetitive DNA at subtelomere and ribosomal DNA regions

Telomere binding protein Stn1 forms the CST (Cdc13/CTC1-STN1-TEN1) complex in budding yeast and mammals. Likewise, fission yeast Stn1 and Ten1 form a complex indispensable for telomere protection. We have previously reported that stn1-1, a high-temperature sensitive mutant, rapidly loses telomere DNA at the restrictive temperature due to frequent failure of replication fork progression at telomeres and subtelomeres, both containing repetitive sequences. It is unclear, however, whether Stn1 is required for maintaining other repetitive DNAs such as ribosomal DNA. In this study, we have demonstrated that stn1-1 cells, even when grown at the permissive temperature, exhibited dynamic rearrangements in the telomere-proximal regions of subtelomere and ribosomal DNA repeats. Furthermore, Rad52 and γH2A accumulation was observed at ribosomal DNA repeats in the stn1-1 mutant. The phenotypes exhibited by the stn1-1 allele were largely suppressed in the absence of Reb1, a replication fork barrier-forming protein, suggesting that Stn1 is involved in the maintenance of the arrested replication forks. Collectively, we propose that Stn1 maintains the stability of repetitive DNAs at subtelomeres and rDNA regions.     

Responses of Heat Shock Proteins hsp27, αB-Crystallin, and hsp70 in Rat Brain After Kainic Acid-Induced Seizure Activity

We determined the changes in the levels of the mammalian small heat shock protein of 25-28 kDa (hsp27) and the hsp alphaB-crystallin in various regions of rat brain after kainic acid-induced seizure activity by means of specific immunoassays. The levels of hsp27 in the hippocampus and entorhinal cortex were markedly increased and reached a maximum (1.5-2 microg/mg of protein) 2-4 days after the seizure. The levels of hsp27 in these regions were considerably high even 10 days after the seizure. A marked increase in levels of mRNA for hsp27 was also observed in the hippocampus of rats 1-2 days after the seizure. A severalfold increase in the levels of alphaB-crystallin was observed in the hippocampus and entorhinal cortex of rats 2 days after the seizure. However, the maximum levels were <50 ng/mg of protein. The levels of protein sulfhydryl group and glutathione were significantly reduced in the hippocampus of rats at 24 h after the seizure, which might have enhanced the expressions of hsp27 and alphaB-crystallin. The expression of inducible mammalian hsp of 70 kDa (hsp70) was also enhanced in the hippocampus of rats after the seizure, as detected by western and northern blotting analyses. Immunohistochemically, an intensive staining of hsp27 was observed in both glial cells and neurons in the hippocampus, piriform cortex, and entorhinal cortex of rats with kainic acid-induced seizure. However, in the cerebellum, where the receptors for kainic acid are also rich, hsp27 was barely induced in the same rats. This might be due to high levels of the cerebellar calcium-binding proteins parvalbumin and 28-kDa calbindin-D, which might have a protective effect against the kainic acid-inducible damage.     

Self-assembled pH-responsive hydrogels composed of the RATEA16 peptide

Peptide RATEA16 spontaneously self-assembled into higher-order nanofiber hydrogels with extremely high water content (>99.5% (wt/vol)) under physiological condition. The hydrogels could undergo pH-reversible transitions from viscous solution to elastic hydrogel and to precipitate. The supramolecular self-assembly and the three phase transitions are driven by hydrophobic interactions, intermolecular hydrogen bonds, and a combination of attractive or repulsive electrostatic interactions. These hydrogels are rich in beta-sheet nanofibers, as demonstrated by CD and FTIR data. Rheological measurements reveal that the viscoelasticity of the material can be tuned by environmental pH and peptide concentration. The storage modulus of the hydrogels increases with increasing peptide concentration, and the self-assembled hydrogels are able to recover from mechanical breakdowns. AFM images show that the elasticity is attributed to a network nanostructure consisting of fibrous self-assemblies. The hydrogels are promising for a variety of possible biomedical applications, including drug delivery.