Identification of extremely halophilic archaea associated with adult <Emphasis Type="Italic">Artemia urmiana</Emphasis>

The brine shrimp, Artemia is the dominant macrozooplankton present in many hypersaline environments. Artemia urmiana is the only macroscopic organism in Urmia Salt Lake (Iran), and the high salinity of the lake makes it a suitable environment for halophilic archaea too. Because of common environment for Artemia and extreme halophiles; this investigation is concentrated on studying the relationship between Artemia and halophilic archaea in Urmia Lake. In this study first the procedure of arhaea isolation was done. Then, isolated strains were sub-cultured and DNA was extracted and amplified by PCR using specific primers for amplifying archaeal 16S rRNA. The amplified archeal DNA fragments were purified, and sequenced. 16S rRNA sequences were compared to known sequences using the NCBI BLAST program. Sequences relating to Halorubrum, Haloarcula and Halobacterium species were identified in Urmia Salt Lake water and Artemia adults and the phylogenetic tree of different species was constructed. Only Halorubrum species were present in association with Artemia. They belong to Halobacteriaceae family of archeae which are isolated from different salt lakes in different parts of world and we could show their existence in adult Artemia, another organism living in hypersaline enviroments.     

Engineering and introduction of <Emphasis Type="Italic">de novo</Emphasis> disulphide bridges in organophosphorus hydrolase enzyme for thermostability improvement

The organophosphorus hydrolase (OPH) has been used to degrade organophosphorus chemicals, as one of the most frequently used decontamination methods. Under chemical and thermal denaturing conditions, the enzyme has been shown to unfold. To utilize this enzyme in various applications, the thermal stability is of importance. The engineering of de novo disulphide bridges has been explored as a means to increase the thermal stability of enzymes in the rational method of protein engineering. In this study, Disulphide by Design software, homology modelling and molecular dynamics simulations were used to select appropriate amino acid pairs for the introduction of disulphide bridge to improve protein thermostability. The thermostability of the wild-type and three selected mutant enzymes were evaluated by half-life, ΔG inactivation (ΔGi) and structural studies (fluorescence and far-UV CD analysis). Data analysis showed that half-life of A204C/T234C and T128C/E153C mutants were increased up to 4 and 24 min, respectively; however, for the G74C/A78C mutant, the half-life was decreased up to 9 min. For the T128C/E124C mutant, both thermal stability and Catalytic efficiency (kcat) were also increased. The half-life and ΔGi results were correlated to the obtained information from structural studies by circular dichroism (CD) spectrometry and extrinsic fluorescence experiments; as rigidity increased in A204C/T2234C and T128C/E153C mutants, half-life and ΔGi also increased. For G74C/A78C mutant, these parameters decreased due to its higher flexibility. The results were submitted a strong evidence for the possibility to improve the thermostability of OPH enzyme by introducing a disulphide bridge after bioinformatics design, even though this design would not be always successful.     

Synthesis and antioxidant properties of substituted 3-benzylidene-7-alkoxychroman-4-ones

A series of 3-benzylidene-7-alkoxychroman-4-one derivatives were synthesized and evaluated for their antioxidant activities. The antioxidant activity was assessed using three methods, namely, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), and thiobarbituric acid reactive substances (TBARS) assays. 3-Benzylidene-7-alkoxychroman-4-one derivatives bearing catecholic group on benzylidene moiety exhibited excellent antioxidant activity. Compounds having catechol moiety exhibited potent antioxidant activities in all tested methods and they were more active than the reference drug, Trolox.     

Cytochrome P-450 model reactions: efficient and highly selective oxidation of alcohols with tetrabutylammonium peroxymonosulfate catalyzed by Mn-porphyrins

A novel biomimetic method for rapid oxidation of a wide range of benzylic, allylic, aliphatic, primary and secondary alcohols to the related aldehydes and ketones using Bu(4)NHSO(5) catalyzed by Mn(TPP)OAc/pyridine system with high to excellent yields and excellent selectivity has been developed. The high turnover rates obtained in this catalytic system represent a high efficiency and also relative stability of Mn-porphyrin catalyst towards oxidative degradation. The presence of an electron-withdrawing group on the phenyl ring of both benzyl alcohol and porphyrin ligand increases the reactivity of substrate as well as catalytic activity of Mn-porphyrin catalyst in the oxidation reaction.     

Determination of clarithromycin in human serum by high-performance liquid chromatography after pre-column derivatization with 9-fluorenylmethyl chloroformate: application to a bioequivalence study

A sensitive liquid chromatographic method for the analysis of clarithromycin, a macrolide antibiotic, in human serum using pre-column derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) is described. The method involved liquid-liquid extraction of the drug and an internal standard (amantadine) followed by pre-column derivatization of the analytes with FMOC-Cl. A mixture of 0.05 M phosphate buffer containing triethylamine (2 mL L(-1); pH 3.8) and methanol (17:83, v/v) was used as mobile phase and chromatographic separation was achieved on a Shimpack CLC-ODS column. The eluate was monitored by a fluorescence detector with respective excitation and emission wavelengths of 265 and 315 nm. The analytical method was linear over the concentration range of 0.025-10 microg mL(-1) of clarithromycin in human serum with a limit of quantification of 0.025 microg mL(-1). The assay is sensitive enough to measure drug levels obtained in human single dose studies. In the present method, sensitivity and run time of analysis have been improved, and successfully applied in a bioequivalence study of three different clarithromycin preparations in 12 healthy volunteers.     

Association between miR-34b/c rs4938723 polymorphism and risk of cancer: An updated meta-analysis of 27 case-control studies

Several studies investigated the association between miR-34b/c rs4938723 polymorphism and the risk of several human cancers, but the findings remain inconclusive. To evaluate the impact of miR-34b/c rs4938723 on cancer risk, we performed a meta-analysis on all available studies including 12 361 cancer cases and 14 270 controls. Eligible studies were identified by searching PubMed, Web of Science, Scopus, and Google scholar databases. Pooled odds ratios with 95% confidence intervals were calculated in codominant, dominant, recessive, overdominant, and allele models to quantitatively estimate the association. The overall findings showed no significant association between miR-34b/c rs4938723 polymorphism and cancer risk in codominant, dominant, recessive, overdominant, and allele inheritance model. However, in stratified analysis by cancer types, the rs4938723 polymorphism significantly increased the risk of gastrointestinal cancer, hepatocellular carcinoma. In addition, the rs4938723 polymorphism was associated with decreased risk of esophageal squamous cell carcinoma, colorectal cancer, and acute lymphoblastic leukemia. The findings did not support an association between rs4938723 variant and digestive tract as well as gastric cancer. In summary, the findings of this meta-analysis indicated that the miR-34b/c rs4938723 polymorphism might be associated with some cancer development. Larger and well-designed studies are necessary to estimate this association in detail.     

Identification of the amino acids in the Major Histocompatibility Complex class II region of Scottish Blackface sheep that are associated with resistance to nematode infection

Lambs with the Major Histocompatibility Complex DRB1*1101 allele have been shown to produce fewer nematode eggs following natural and deliberate infection. These sheep also possess fewer adult Teladorsagia circumcincta than sheep with alternative alleles at the DRB1 locus. However, it is unclear if this allele is responsible for the reduced egg counts or merely acts as a marker for a linked gene. This study defined the MHC haplotypes in a population of naturally infected Scottish Blackface sheep by PCR amplification and sequencing, and examined the associations between MHC haplotypes and faecal egg counts by generalised linear mixed modelling. The DRB1*1101 allele occurred predominately on one haplotype and a comparison of haplotypes indicated that the causal mutation or mutations occurred in or around this locus. Additional comparisons with another resistant haplotype indicated that mutations in or around the DQB2*GU191460 allele were also responsible for resistance to nematode infections. Further analyses identified six amino acid substitutions in the antigen binding site of DRB1*1101 that were significantly associated with reductions in the numbers of adult T. circumcincta.     

Otomycosis in the South of Iran with a High Prevalence of Tympanic Membrane Perforation: A Hospital-Based Study

Mycopathologia - Otomycosis is a superficial infection of the external ear caused by fungal pathogens. The genera Aspergillus and Candida are considered the main fungal causative agents, with the...     

Influence of meteorological parameters and PM2.5 on the level of culturable airborne bacteria and fungi in Abadan,Iran

In recent years, monitoring of airborne bacteria and fungi concentrations has obtained increasing universal attraction not only for influences on ecological balance but also for evaluating their public health consequences. In this study, we aimed to investigate culturable airborne bacteria and fungi levels in different sites of Abadan, and their association with meteorological parameters and PM_2.5 levels. Abadan is one of the most industrialized cities in the southwest of Iran where over the current decade has experienced lots of dust storm episodes. In total, 400 air samples were collected in 6 months (autumn and winter) using a single-stage viable Andersen cascade impactor for sampling airborne bacteria and fungi and portable DustTrak Aerosol Monitor 8520 for measuring PM_2.5 concentrations and meteorological parameters. Microbial concentrations showed a significant difference between various sites over the study period with averages of 569.57?±?312.64 and 482.73?±?242.86 CFU/M³ for bacteria and fungi, respectively. The air temperature had a significant effect on the concentration of both airborne bacteria and fungi. A significant positive correlation between relative humidity and fungi but no correlation between relative humidity and bacteria concentrations were observed. The average airborne PM_2.5 concentrations of all sites among the study period was 93.24?±?116.72 μg/m³. The atmospheric bacterial and fungal communities were strongly positively correlated with the ambient PM_2.5 level. The levels of airborne bacteria and fungi along with PM_2.5 in the air of the city were relatively higher than the recommended levels. Therefore, the best course of action is needed to control emission sources. Further studies are also needed to evaluate the clinical analysis of the health effects of exposure to these pollutants.

     

In silico analysis and modeling of ACP-MIP–PilQ chimeric antigen from Neisseria meningitidis serogroup B

Background:

Neisseria meningitidis, a life-threatening human pathogen with the potential to cause large epidemics, can be isolated from the nasopharynx of 5–15% of adults. The aim of the current study was to evaluate biophysical and biochemical properties and immunological aspects of chimeric acyl-carrier protein-macrophage infectivity potentiator protein-type IV pilus biogenesis protein antigen (ACP-MIP-PilQ) from N. meningitidis serogroup B strain.

Methods:

Biochemical properties and multiple alignments were predicted by appropriate web servers. Secondary molecular structures were predicted based on Chou and Fasman, Garnier-Osguthorpe-Robson, and Neural Network methods. Tertiary modeling elucidated conformational properties of the chimeric protein. Proteasome cleavage and transporter associated with antigen processing (TAP) binding sites, and T- and B-cell antigenic epitopes, were predicted using bioinformatic web servers.

Results:

Based on our in silico and immunoinformatics analyses, the ACP-MIP-PilQ protein (AMP) can induce high-level cross-strain bactericidal activity. In addition, several immune proteasomal cleavage sites were detected. The 22 epitopes associated with MHC class I and class II (DR) alleles were confirmed in the AMP. Thirty linear B-cell epitopes as antigenic regions were predicted from the full-length protein.

Conclusion:

All predicted properties of the AMP indicate it could be a good candidate for further immunological in vitro and in vivo studies.Key Words: Chimeric protein, In silico, Neisseria meningitides, serogroup B, Vaccine