Zhonghua Minguo wei sheng wu ji mian yi xue za zhi = Chinese journal of microbiology and immunology最新文献

The simian virus 40 (SV40) small t (t) antigen is known to be able to induce cell proliferation and to enhance the transforming activity of SV40 large T antigen. Here we report that t could also enhance the transforming activity of v-src oncogene. When t was transfected into the v-src-transformed NIH3T3 cells, the t-expressing stable clones grew faster and grew to higher density than did the parental or vector-transfected cells. Furthermore, these t-expressing cells also showed better plating efficiency and grew more efficiently in soft agar than did the parental or vector-transfected cells. More importantly, the t-expressing cells displayed high tendency to aggregate and detached easily from the dishes, while the parental or vector-transfected cells never exhibited such phenotype. This last observation suggests that t may affect the expression of adhesion molecules in the v-src-transformed NIH3T3 cells. Taken together, we concluded that t could enhance the transforming activity of v-src and alter the transformed morphology of v-src-transformed NIH3T3 cells.

A monthly survey on the distribution of human-pathogenic Vibrionaceae of the seawater from five principal harbors in Taiwan was conducted by National Quarantine Service from July, 1991 to February, 1994. Of the total 1,167 Vibrionaceae isolates, strains of Vibrio alginolyticus (449 strains) were the most frequently isolated, followed by Vibrio parahaemolyticus (262) , Aeromonas hydrophila (153), Vibrio cholerae non-O1 (86), and Vibrio vulnificus (67). None of Vibrio cholerae O1 was isolated. The pH, salinity, and water temperature in this study ranged from 5.8 to 8.6, 0.1 to 4.2% , and 15 to 34 degrees C, respectively. It is concluded that the family Vibrionaceae exists autochthonously around the coastal waters in Taiwan.

The etiological relationship of human foamy virus (HFV), which is a spumaretrovirus, with human diseases is not clear. We analyzed thymus specimens from four patients with myasthenia gravis for the presence of HFV proviral genome by polymerase chain reaction (PCR). The results showed the presence of both 257 base pair (bp) and 299 bp DNA fragments representing a part of gag and bel-2 sequences, respectively, in all four thymuses. Their specificity was confirmed by Southern blot hybridization with the corresponding probes. This was also confirmed by sequence analysis, although there were some point mutations. We confirmed the presence of gag related sequence, a 1353 bp Xba I-cleaved DNA fragment in all four thymus samples, a 693 bp fragment in two (#3 and #4) and a 4300 bp Hind III-cleaved DNA fragment in another two (#1 and #4), indicating possible chromosomal integration of the HFV partial genome. To our knowledge, this is the first report on the presence of HFV genome in thymus tissues of myasthenia gravis patients. Our efforts to isolate the infectious HFV by cultivation of the tissues were not successful. Low titers of neutralizing antibody were detected in all four patients' serum samples. The possible role of the HFV in this autoimmune disease needs further investigation.

A bile medium was developed for rapid presumptive identification of beta hemolytic group B streptococci. Of 131 clinical isolates of group B streptococci, 125 (95.4%) yielded positive reaction within 6 h incubation. No false positive reaction was found in 134 clinical isolates of groups A, C, F, and G beta-hemolytic streptococci. The sensitivities of the bile medium, rapid hippurate hydrolysis and modified LAL-1 medium were 95.4, 98.5 and 93.1%, respectively. All three media showed 100% specificity. Therefore, the bile medium provides as an additional medium for rapid presumptive identification of group B streptococci.

Helicobacter pylori has been known to be associated with gastric adenocarcinoma by case control studies. However, significant portion of patients with gastric carcinoma are negative for H. pylori by serological test. To further detect the presence of H. pylori infection in serum and tissue of patients with gastric adenocarcinoma, paired tissues and serum samples from 32 patients with gastric adenocarcinoma were tested. Antibodies to H. pylori were tested by an enzyme linked immunosorbent assay (ELISA) and a Western blot analysis. H. pylori in tumor and non-tumor parts of gastric tissues were examined by histology and polymerase chain reaction (PCR). For serum antibody, eighteen (56%) of these patients were positive by ELISA while 24 (75%) were positive by Western blot. For tissue H. pylori genome, 14 were positive by histology while 28 (87%) were positive by PCR. Southern blot analysis of both tumor and non-tumor tissues revealed no evidence of integration of H. pylori DNA in the human genomes. These results suggest that H. pylori infection can be detected in most patients with gastric adenocarcinoma, and PCR and Western blot can further identify seronegative patients.

T-protein serotypes and antimicrobial susceptibility of a total of 139 group A streptococci (GAS) strains isolated in Taiwan area in 1993 and during the outbreak of scarlet fever in 1994 were analyzed. All strains were T-typable, and T12 (42.46%) and T4 (38.85%) were the dominant T types. According to the results of analysis of antimicrobial susceptibility, all GAS strains were divided into 9 resistotypes, A (all susceptible), B (resistant to tetracycline), C (resistant to erythromycin and tetracycline), D (resistant to chloramphenicol and tetracycline), E (resistant to chloramphenicol and clindamycin), F (resistant to chloramphenicol, clindamycin and tetracycline), G (resistant to clindamycin, erythromycin and tetracycline), H (resistant to chloramphenicol, clindamycin, erythromycin and tetracycline), and I (resistant to chloramphenicol, clindamycin, erythromycin, tetracycline and vancomycin). Type B (37.42%) was the dominant type. Type A (25.91%), and type H (26.63%) also appered with high incidence. Most of strains isolated from Mid-Taiwan were type H. Only one strain, that was isolated in I-lan, was resistant to vancomycin, in addition to resistant to chloramphenicol, clindamycin, erythromycin, and tetracycline. All strains were susceptible to penicillin G, ampicillin, and ceftriaxone. Some strains were resistant to chloramphenicol (32.38%), clindamycin (30.22%), erythromycin (31.66%), tetracycline (73.39%), and vancomycin (0.70%). During the outbreak of scarlet fever in 1994, the dominant T types of strains isolated in North-Taiwan and Mid-Taiwan were T4 and T12, respectively, and the major resistotypes of those strains were B and H types, respectively. These clues suggested that the outbreaks occurring in North-Taiwan and Mid-Taiwan may have no epidemiological linkage between each other.

In biotechnology, animal cell culture is an important process for the production of many biologicals such as vaccines, monoclonal antibodies, or other recombinant products. Among many established continuous cell lines, Vero cells can be maintained in many passages in cultures without inducing tumorigenicity and have been recommended by World Health Organization for the production of human biologicals. Owing to its anchorage-dependent growth characteristics, Vero cells can be grown on microcarrier in a suspension vessel where microcarrier provides the culture system with a high culture surface to volume ratio. In this paper we compared the growth kinetics of Vero cells on Cytodex 1 microcarrier in a 20-liter fermentor vs. 100 ml spinner flask culture. The kinetics of Vero cell growth in the 20-liter fermentor was similar to the results obtained from small spinner flask culture, as determined by cell specific growth rate or corresponding doubling time. The approximately 150-fold increase in culture vessel volume did not compromise the growth kinetics of Vero cells, suggesting the system is applicable for large stirred-tank fermentor cultures.

To further elucidate the role of dietary frying oil in the pathogenesis of autoimmune diseases, two groups of NZB/W F1 mice were fed with diets containing 20% fresh oil and frying oil, respectively. All these mice were followed up serum anit-DNA antibody levels, proteinuria and life span regularly. Our data suggested: 1) higher IgG anti-ss, dDNA antibody levels were noted in mice fed with fresh oil compared to those of the frying oil group; 2) lipopolysaccharide (LPS)-stimulated spleen cells of mice fed with frying oil produced higher IL-10 compared to that of fresh oil group; 3) IL-6, TNF-alpha and PGE2 produced by macrophages of dietary frying oil group were higher, although not statistically significant, than those of fresh oil group. Different degree of deterioration of dietary oil has been found to affect immune response in autoimmune mice.

Nested polymerase chain reaction (PCR) was applied to identify the serotypes of Rickettsia tsutsugamushi isolated from patients. The primers used for PCR were based on the nucleotide sequences encoding a 56 kDa antigen of rickettsiae. Comparing to the conventional immunofluorescence assay (IFA), which displays a considerable degree of cross-reactivity among different species, the result obtained suggests that the polymerase chain reaction method is much more reliable than IFA.

Antigen binding activities of 25 kinds of filter papers, including nitrocellulose (NC), nylon or polyvinylidine difluoride (PVDF), in the binding of 5 viruses, 3 bacteria, 2 mycoplasmas and 1 chicken serum protein antigens in dot immunoassay were compared. Immobilon affinity membrane type D (IAM-D) was found best in binding viral antigens, followed by Ultrabind SV-450 (SV-450). SV-450 was found best in binding bacterial antigen, followed by Ultrabind US-450 (US-450), IAM-D and NC 0.45 micron. IAM-D was the best in binding mycoplasma antigen, followed by Ultrabind HP, US-450, NC 0.2 micron. Overall, IAM-D had the best capability in the binding of the antigens.