Iranian Biomedical Journal
Year:2003 | Volume:7 | Issue:1|Papers Count:8

Anopheles pulcherrimus Theobald has a wide distribution in western Asia and is a potential vector of malaria in Iran. We have examined the rDNA-ITS2 (internal transcribed spacer 2) region of An. pulcherrimus specimens collected during the two peaks of activity (May-June and October-November) from Sistan and Baluchistan province, southeastern Iran. There were no consistent differences between specimens originated from different ecological areas. Total amplified fragment is 490 bp, which is within the range of the records repeated from other anophelines. ITS2 was 350 bp long in all individuals examined with identical sequence in different populations. Sequence analysis revealed its differences with two other important malaria vectors in the region, An. culicifacies and An. fluviatilis. However, based on ITS2-derived phylogenetic tree, the nearest taxa to An. pulcherrimus is a new species related to An. Culicifacies and called species X in An. culicifacies species complex. These data may provide a better understanding on dynamics of malaria transmission in southeastern corner of Iran and neighboring countries. Moreover, the extent of the genetic variation in these mainly sympatric species could result in designing and application of species-specific diagnostic tools, which can facilitate the management of malaria control program in the region

Rotavirus, a triple-layered non-enveloped member of the Reoviridae family, obtained a transient membrane envelope when newly synthesized subviral particles bud into the endoplasmic reticulum (ER). As rotavirus particles mature, they lose their transient membrane and obtain outer layer. It is mostly believed that only double layered particles bud into the ER. The present study describes that the single layered particles can also bud into the ER and become the immediate precursors of the mature virions. Virus replication was studied within a line of African green monkey kidney (BSC-1) cells infected with simian rotavirus SA11. The virus intermediate capsid protein (VP6) was localized within the infected cells using protein A-gold. Monospecific antibody to VP6 was the primary antibody. The electron micrographs of budding sites of ER showed two different sizes of subviral particles. The gold particles were seen on the double layered particles and very little in the cytoplasm and some on ER or very close to it. These results indicate that the single layered particles are also capable of being the precursor of the triple layered and obtain the VP6 while budding into the ER.

The pLE2SCX vector was developed for the stable expression of exogenous genes in the protozoan parasite Leishmania. The pLE2SCX construct contains three independent selection markers: herpes simplex virus thymidine kinase (HSV-TK), cytosine deaminase (CD) and streptothericin acetyltransferase gene (sat) in multiple cloning site, flanking by 5’ and 3’ untranslated regions of the previously cloned Leishmania major hexa-binding protein gene. Selection was based on resistance to the nourseothericin (Ns) which corresponds to sat gene. The two negative selection; HSV-TK and CD genes, make the transformed cell sensitive to ganciclovir (GCV) and 5-fluorocytosine (5-FC). The vector was introduced into Leishmania promastigotes by electroporation and maintained as circular form. The selected transfectants were not grown on media with GCV or 5-FC. Using two drug sensitive selectable markers together on a vector is a novel strategy in gene cloning in Leishmania. This stable transfection vector has allowed the permanently expression of several different exogenous genes at the same time in Leishmania

Glycoconjugates and their programmed changes during the course of development in the cell-surface as well as in the extracellular matrix, are known to affect cell differentiation, cellular interaction and other developmental phenomena during embryogenesis. The purpose of this study was to localize N-acetylgalactosamin as well as fucose-containing glycoconjugates in situ during thymus development. Staged embryos or thoracic segments were fixed and processed for lectin histochemistry studies. Five microns paraffin-embedded sections were incubated with horseradish peroxidase conjugated lectins from Dolichos biflorus and Aleuria aurantia specific for N-acetylgalactosamine and fucose, respectively. Our results revealed unique reaction of T-cells with Dolichos biflorus and the presence of a fucosylated glycoconjugate in microenvironments of the developing thymus including extracellular matrix and developing Hassall bodies. The time and distribution of staining with these two lectins suggest that fucosylated glycoconjugates and N-acetylgalactosamin terminal sugars may play significant role in intrathymic microenvironment that might cause differentiation of T-lymphocytes.

The hypotensive effect of garlic has been well-documented in human subjects and animals. Since endothelial activity regulates vascular reactivity in physiological and pathophysiological conditions, the aim of the present study was to investigate the effect of garlic on endothelium-dependent and independent relaxation of rat aorta for elucidation of mechanism of the garlic anti-hypertensive effect. Four and eight weeks after treatment with garlic extract, aortic rings were studied for relaxation response to acetylcholine and isosorbide dinitrate. The obtained results showed that endothelium-dependent relaxation response of aortic rings to acetylcholine, from rats treated with garlic for 4 and 8 weeks, increases about 5-24% and 3-27%, respectively compared to controls. But, endothelium-independent relaxation response to isosorbide showed no difference in all groups. Moreover, the relaxant effect of garlic extract was time-dependent. The obtained findings strongly suggest that garlic exerts its relaxant effect through endothelium by production and/or releasing of endothelium-derived relaxing factor.

In the present study, 110 fungal strains of Persian Type Culture Collection (PTCC) including some selected strains isolated in various screening projects were tested for their potentiality to produce lovastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reduc-tase), the rate-limiting enzyme of cholesterol biosynthesis. The fungal strains were cultivated in a two-stage submerged fermentation followed by screening by TLC. All positive results were evaluated by confirmatory HPLC. Nine species of four genera were found to be lovastatin producers. Aspergillus terreus was the best lovastatin producing strain with a level of 55 mg lovastatin per liter of screening production medium

Cockroaches were collected from hospitals, houses and poultry sheds in various parts of Isfahan (Iran) and identified to species. In total, seven species of cockroaches in seven genera were identified: Blatta lateralis, Polyphaga aegyptiaca, Arenivaga roseni and Parcoblatta spp. Three species Periplaneta americana, Blattella germanica and Supella longipalpa (Blattidae and Blattellidae) were more abundant than the others. In another study, forty cockroaches were collected from hospitals in two experiments and were studied for the presence of Salmonella spp. Salmonella (Black colonies on SS agar with urease negative) were isolated from about 70 percent of the cockroaches collected from hospitals. Some of the isolated Salmonella were resistant to antibacterial drugs in a susceptibility test. Isolation of Salmonella from cockroaches collected from hospitals suggests that cockroaches act as natural reservoirs of Salmonella. A second study was conducted to determine if individual B. germanica could transfer Salmonella from an infected food source and then infects uncontaminated colony members. The results showed that the inoculation of 106 CFU of Salmonella into cockroaches via their food could infect the uncontaminated cockroaches. These contaminated cockroaches transfer infection to other colony members. Salmonella is stable in cockroaches for more than 10 months.

Enoxolone is a major component of a traditional plant called Licorice. This substance has been found to contain some pharmaceutical properties including of both antiviral and antifungal activities. Microbiological studies have identified more than seven periodontopathogens in the periodontal pockets, which less than 4 species were capnophile. The purpose of this study was to investigate the in vitro antibacterial effects of enoxolone against isolated periodontopathogenic and capnophilic bacteria. Total specimens were collected with sterile paper points from the deepest periodontal pockets of 400 patients, and cultured under capnophilic condition using selective media. The isolates were characterized to species level by conventional biochemical tests. Antibacterial activities of enoxolone against those microorganisms were investigated by determining minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. In this study, 186 species of Actinobacillus actinomycetemcomitans (46.5%), 120 species of Eikenella corrodens (30%) and 136 Capnocytophaga species (34%) were isolated from specimens of periodontitis patients. The rate of periodontitis specimens associated with monobacteria and polybacteria were 105 (26.3%) and 158 (39.5%), respectively. The MIC of enoxolone was 8, 16 and 8 mg/ml for A. actinomycetemcomitans, E. corrodens and Capnocytophaga species, respectively and the MBC was 16 mg/ml for all species. It is concluded that enoxolone with above mentioned concentration is effective against isolated periodontopathogenic and capnophilic bacteria.