Iranian Biomedical Journal
Volume:3 Issue: 3, Oct - Jul 1999

It is difficult to distinguish between clinically significant slowly-growing, non-pigmented mycobacteria, notably to separate M. avium and M. intracellulare from one another and from M. scrofulaceum strains. The purpose of this study was to evaluate the extent to which 16S rRNA sequencing could be used to highlight the taxonomic relationships of the mycobacterial strains, which are difficult to separate using conventional microbiologic methods. Almost the complete sequences of the 16S rRNA of several M. avium-intracellulare complex strains were determined following the isolation and direct sequencing of the amplified genes. The sequences were aligned with those of previously studied mycobacteria, and phylogenetic trees inferred by using the Fitch-Magoliash, neighbour-joining and maximum parsimony methods. It is evident from the result of the current study that the nucleotide signature regions of 16S rRNA provide valuable information for the differentiation of M. avium-intracellulare complex strains

The adherence property of 70 verotoxigenic E. coli (VTEC) strains, not belonging to O157: H7 serotype (non-O157) was checked on HeLa cells adherence assay. These strains were isolated from patients with diarrhea and healthy individuals. The results obtained in this study revealed that localised adherence (LA) was manifested by 3 strains of which two belonged to serogroups O111, O127 and the third one was non-enteropathogenic E. coli. The LA pattern was not found among strains isolated from healthy persons (P<0.001). Diffuse adherence (DA) was exhibited by six strains equally distributed among both groups and none of them belonged to enteropathogenic strains. However, aggregative adherence (AA) was manifested by 9 strains and was the most frequent among VTEC strains isolated from diarrheal cases (P<0.001) and was comprised of non-enteropathogenic E. coli strains. Non-specific adherence (NSA) was observed in 17 strains. Overall, the results obtained revealed that AA and LA adherence were significantly (P<0.001) associated with strains isolated from patients

Fresh semen obtained from infertile men occasionally exhibits the total absence of motile sperm (100%asthenozoospermia). Vitality tests may reveal that a proportion of the immotile sperm has functional membranes, which are considered viable. An easy test for the prior determination of sperm viability may assist in sperm selection for the microinjection of oocytes. The main objective of this study was to apply three standard vitality tests on the asthenozoospermia samples from infertile men. A total of 30 semen samples with >50% immotile sperm were obtained for this study. Each semen sample wasdivided into three equal aliquots following the preliminary evaluation of semen parameters. Threevitality tests of eosin-Y, hypoosmotic swelling (HOS) and pentoxifylline (PX) were applied on allsamples. A total of 100 spermatozoa were then evaluated for the sign of viability. The percentage of normal morphology and sperm count were within the normal range of 31.8 ± 15.9% and 55.8 ± 46.6´ 106 per ml., respectively. Following the application of eosin-Y, 45.2 ± 15.2% of spermatozoa were unstained (alive). In addition, 51.9 ± 18.6% and 52.7 ± 21.1% of sperm were observed to be viable with HOS and PX tests, respectively. Three samples with total asthenozoospermia demonstrated with 37.61%, 27%, and 33.33% viability after the application of eosin-Y, HOS, and PX tests, respectively. The results indicate that the vitality tests are very useful in differentiating live sperm from dead one, even in the samples with total asthenozoospermia. Also, PX may be a more accurate vitality test with a therapeutic application during the microinjection cycles. It not only has the ability to differentiate live sperm, but also enhances motility.

Elaboration of different toxins by enterotoxigenic E. coli has been considered as one of the main virulence factors contributing to the manifestation of disease caused by these microorganisms. Various strategies have been employed to raise antibodies against these toxins as a line of defense. In this study, the 3’ terminus of the gene that codes for the binding subunit of the heat-labile enterotoxin of E. coli (LTB) was fused to the 5’ terminus of a truncated heat-stable enterotoxin of E. coli (ST) with a region coding for 7 amino acids separating the two moieties. The fused gene was sequenced and subsequently subcloned in the pET23a (+) expression vector in the EcoRI/HindIII sites. The construct was transferred into the E. coli strain, BL21 (DE3) pLysS and isopropyl-b -D-thiogalactopyranoside (IPTG) was used for induction. The expression of the LTB and ST in the fused protein was assessed using two commercially available kits. SDS-PAGE and Western blot were also used to examine the expressed protein. The results indicated the low expression of both toxin moieties that were recognizable by the commercially available antibodies and the expressed protein was non-toxic as indicated by suckling mouse assay

Prostate-specific antigen (PSA) was purified to homogeneity from human seminal plasma by ion-exchange chromatography on a CM-Sephadex C-50 and by gel filtration on a Sephacryl S-200 column. A single 33-kDa protein band appeared in SDS-PAGE. High pressure liquid chromatography (HPLC) of the purified protein produced a single peak, while isoelectric focusing demonstrated the presence of five different isoforms of this protein. The immunoreactivity of the purified PSA was checked by Western blotting. This simple two-step method can be used for a large-scale preparation of the purified PSA for the clinical tests and also for further investigative studies on the biological properties of this protein

The Immunogenicity of g -irradiated tachyzoites of a highly virulent strain of Toxoplasma gondii (RH strain) was investigated. Immunized mice survived challenge infection and displayed increased interferon gamma (INF-g) production. On the other hand, nonimmunized controls died after 10 days and displayed a significantly decreased lymphoproliferative response to Concanavalin A (Con A). No tachyzoites were detected in peritoneal exudates of the immunized mice 10 days after challenge. These results indicate that the vaccination with g -irradiated tachyzoites not only protects the mice against challenge infection, but may circumvent the danger of the vaccine being life-threatening because of remaining tachyzoites inside macrophages posing as a latent infection

For the evaluation of autoantibodies in Pemphigus vulgaris (PV), an indirect ELISA assay was developed by using a semi-purified human epidermal skin extracted with approximately a molecular weight (M.W.) of 130-160 kDa. The evaluation of Pemphigus IgG, IgM and IgA autoantibodies in 75 patients and 50 control sera indicated that this indirect ELISA assay was a useful method for the detection of Pemphigus autoantibodies. Data of this study suggested that the mean OD (Optical Density) of specific IgG autoantibody was elevated in PV patients compared with the controls. The percentages of the total serum IgM and IgA antibodies were not statistically significant between patients and controls

Arthrobotrys amerospora (ATCC 34468) produced glucoamylase in a semi-synthetic medium containing starch as a sole carbon source. Polyacrylamide gel electrophoresis of crude glucoamylase showed three isoenzymes. They were designated as glu I, glu II and glu III according to their electrophoretic mobility. These iso-glucoamylases were purified by column chromatography using DEAE-Sephadex A-50. The major fraction, namely glu I, was subjected to various group specific reagents like NEM, idoacetamide, PALP, DEP, Rose Bengal, NBS and acarbose. N-bromosuccinimide and acarbose totally inhibited glu I. Hg2+ ion did not inhibit glu I activity at 25 m mol concentration. Glu I also showed raw starch activity