Novel ecological niche of Cetobacterium somerae, an anaerobic bacterium in the intestinal tracts of freshwater fish.

AIMS: This study was conducted to clarify the taxonomic status of Bacteroides type A strains with high vitamin B(12)-producing ability that is widely distributed in the intestinal tracts of freshwater fish. METHODS AND RESULTS: Seventeen strains of Bacteroides type A isolated from five fish species were all rod-shaped and gram-negative. The strains were positive for esculin hydrolysis, nitrate reduction, resistance to bile, acid phosphatase, and negative for the production of catalase and urease and the susceptibility to vancomycin. The G+C content of DNA from the 17 strains was 29 x 1-31 x 9 mol%, and 16S rDNA sequence analysis revealed a close phylogenetic relationship between Bacteroides type A strains and Cetobacterium somerae sharing 99 x 7-100% sequence similarity. In addition, strains were capable of producing vitamin B(12) at a rate of 1 x 82-13 x 98 ng ml(-1) in 48 h. CONCLUSION: Phenotypic and phylogenetic characteristics indicated that all isolates previously classified as Bacteroides type A strains belong to C. someare. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provided the important finding of novel niche of vancomycin-resistant bacteria such as C. somerae in the intestinal tract of freshwater fish.

Purification and characterization of chitinases from Clostridium sp. E-16 isolated from the intestinal tract of the South American sea lion (Otaria flavescens).

AIMS: This study was undertaken to examine the properties of chitinases purified from Clostridium sp. E-16, an intestinal bacterium of the South American sea lion (Otaria flavescens). We also elucidated the taxonomic status of this bacterium to better understand the role of intestinal anaerobic bacteria in marine animals. METHODS AND RESULTS: Two chitinases were purified with ammonium sulfate precipitation, affinity chromatography and preparative electrophoresis from culture supernatant fluid from Clostridium sp. E-16. Molecular mass was estimated to be 77 kDa for chitinase 1 and 98 kDa for chitinase 2 by SDS-PAGE. Optimum pH of both purified chitinases was between 5.0 and 7.0. Chitinase 1 was inhibited with Cu(2+), Fe(2+), Hg(2+) and Zn(2+), while chitinase 2 was inhibited with Fe(2+). Phylogenetic analysis using 16S ribosomal DNA (rDNA) sequences and phenotypic characterization revealed that Clostridium sp. E-16 was closely related to Clostridium baratii. CONCLUSIONS: It is likely that chitinases from C. baratii or a C. baratii-like bacterium play an important role in degradation of chitin in the intestinal tract of the South American sea lion and in marine environments. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of chitinase purification and characterization from a marine Clostridium strain.

Selective permeation of hydrogen peroxide through polyelectrolyte multilayer films and its use for amperometric biosensors.

A platinum electrode was coated with polyelectrolyte multilayer (PEM) films to prepare an amperometric hydrogen peroxide sensor which can be used in the presence of possible interferences such as ascorbic acid, uric acid, and acetaminophen. The PEM films were prepared on the surface of a Pt disk electrode by an alternate deposition of polycation and polyanion from the aqueous solutions through electrostatic force of attraction. The Pt electrodes coated with a poly(allylamine)/poly(vinyl sulfate) or poly(allylamine)/poly(styrenesulfonate) film were used successfully for detecting H2O2 selectively in the presence of the possible interfering agents. It was suggested that H2O2 can diffuse into the PEM film smoothly while the ascorbic acid, uric acid, and acetaminophen cannot penetrate the film by a size exclusion mechanism. On the other hand, the electrodes coated with PEM films containing poly(ethyleneimine) or poly(diallyldimethylammonium chloride) were not useful for the selective determination of H2O2. The results were rationalized based on the different permeability of the films due to the different molecular density or packing in the PEM films. The PEM film-coated electrode was useful for constructing glucose biosensors by coupling with glucose oxidase.

Synthesis and Physical Properties of Sterically Congested Cycloalkenes, 1,2-Di-tert-butyl-3,3,5,5-tetramethylcyclopentene and 1,2-Di-tert-butyl-3,3,6,6-tetramethylcyclohexene.

Two sterically congested cycloalkenes (9 and 10), congeners of tetra-tert-butylethylene, were synthesized and characterized. Oxidation of the bicyclic 1,3-dithietane 8 with dimethyldioxirane (DMD) gave the endo,endo-disulfoxide 13, thermal isomerization of which to the endo,exo-disulfoxide 15 followed by oxidation with DMD gave the trioxide 18. Heating 18 in refluxing 1,3-dimethyl-2-imidazolidinone furnished 1,2-di-tert-butyl-3,3,5,5-tetramethylcyclopentene (9) in 69% yield by a 2-fold extrusion process. The reaction of the 1,6-diketone dihydrazone 23 with Se(2)Cl(2) gave the selenadiazoline 34 and the 1,3-diselenetane 35. Heating 34 at 115-130 degrees C gave 1,2-di-tert-butyl-3,3,6,6-tetramethylcyclohexene (10), a "didehydro" derivative of tetra-tert-butylethylene, in 43% yield. The C=C bond in 10 is strained in degree comparable to those of most strained alkenes reported so far.

Pharmacologic management of the arthritic foot and ankle.

The arthritides discussed are presented with many drug therapies because of a not fully understood and accepted cause of the disease process. Similarly, the drug therapies offered are diverse and have mechanisms that are not always fully understood. Because of the destruction and disability the arthritides are capable of and the realization that destruction may be reversible early in the course of the disease, physicians are initiating earlier, aggressive treatment with DMARDs. Long-term outcome studies of the early institution of DMARDs, combination therapies, and newer medications need to be evaluated to produce the most efficient treatment regimens.

Detection of c-Ki-ras oncogene mutation in gastric adenomas with formalin-fixed, paraffin-embedded biopsy materials.

Point mutations at codon 12 of the c-Ki-ras gene were investigated in 103 biopsy tissues from 38 patients with gastric adenoma. DNA from minute specimens of formalin-fixed paraffin-embedded tissue was amplified by nested polymerase chain reaction (PCR) and the restriction fragment length polymorphism (RFLP) method was used to detect mutations of the c-Ki-ras gene. Mutations were detected in 4 of the 38 gastric adenomas (10.5%), but were not detected in intestinal metaplasias and gastric adenocarcinomas. Of the 4 mutation-positive gastric adenomas, the GGT sequence in codon 12 changed to GAT in 2 cases, to GTT in 1 case and to TGT in 1 case. We classified gastric adenomas into three degrees of atypia; mutations were detected only in biopsy tissues with moderate and severe atypia but were not detected in biopsy tissues with mild atypia. When different biopsy tissues from a mutation-positive gastric adenoma were examined, the mutation was not always detected in every tissue sample examined. This suggests that mutations are not homogeneously distributed, even in the same adenoma. It is possible to follow up the mutation of biopsy materials of gastric adenoma by this method.

[A case of schwannoma of intrathoracic right phrenic nerve].

A 22-year old man was admitted because of an abnormal shadow on his chest X-ray film. Radiographic findings revealed that the tumor was located in the right middle mediastinum. At operation a smooth round tumor was found arising from the right phrenic nerve. The tumor was removed with phrenic nerve. Pathohistological examination revealed this tumor was benign schwannoma. Intrathoracic schwannoma usually arise from intercostal and sympathetic nerve and that arising from phrenic nerve is very rare. We removed the tumor by means of cutting his right phrenic nerve because of complete resection. Postoperatively he did well without any respiratory distress. And his respiratory function studies recovered normal 9 months after the operation. We think that schwannoma arising from phrenic nerve should be removed completely and in such a case cutting of the one side phrenic nerve is at ease if the patient have normal respiratory function.

[Esophageal carcinoma with adenoid cystic differentiation--an immunohistochemical study of two cases with special reference to their histological origin].

Two cases of an esophageal carcinoma with an adenoid cystic differentiation are presented. The first was diagnosed histologically as typical adenoid cystic carcinoma, and the other as being a basal cell carcinoma with an adenoid cystic differentiation. We further investigated these tumors and normal esophageal specimens to determine their histological origin by immunohistochemical staining with either polyclonal or monoclonal antibodies to different classes of human keratin. It was found that both tumors were similar in their reactivities with the anti-keratin antibodies to basal cells of the surface squamous epithelia, but not to the cells composing the esophageal glands, suggesting that they were of basal cell origin.