Progress in Biological Sciences
Volume:3 Issue: 2, Summer and Autumn 2013

Microorganisms constitute more than half of the Earth''s biomass and in addition to quantity, they represent great diversity. In January 2013, the number of officially registered names for prokaryotic microorganisms at the genus and species levels were, respectively, approximately 2100 and 12000. Current authorized methods for classification and identification of new microbial taxa are polyphasic approaches which make use of a codified set of characteristics for classification of microorganisms. Here, we present a brief overview of criteria by which prokaryotes are classified and subsequently summarize some recent findings on the microbial flora of Iran. Among all microbial taxa identified to date, six taxa at the genus level and 2 taxa at the species level were first discovered in and reported from Iran. This attests to the existence of a rich microbial diversity in Iran. Among the species, four belong to the Archaea and the others belong to the Bacteria domain. The bacterial taxa consist of six Gram- negative species within Proteobacteria and Bacteroidetes phylems and 20 Gram-positive taxa that are among the Actinobacteria, Firmicutes and related organisms. It is incumbent that further focus be placed on the rich ecological diversity of Iran, and it is expected that this will result in identification of new endemic microorganisms.

Effects of excess concentrations of boron on major cell wall components of tobacco cells (Nicotiana tabacum L. cv. Burley 21) were studied. Pectin, xyloglucan, hydroxyproline-rich glycoproteins (extensin), and arabinogalactan proteins were characterized. Results showed that increased boron supply resulted in significant decrease in cell and cell wall dry weights. Also, high concentrations of boron reduced relative amounts of major wall components. Compared with the normal conditions, increase in certain sugars in pectin (e.g., xylose and its methylated derivative) and decrease in glucose, arabinose, and rhamnose in those treated cells with higher concentrations of boron was significant. The content of hydroxyprolinerich glycoproteins decreased when tobacco cells were supplied with higher concentrations of boron. In these cells, increased ratio of protein to glycan part and increase in hydroxyl lysine among other amino acids were noticeable. Amount of arabinogalactan proteins also decreased as boron supply increased. Excess boron did not alter the composition and concentration of amino acids of arabinogalactan; however, it remarkably increased xylose and glucose but decreased galactose and arabinose concentrations.

The identification of the efficiency of some mtDNA genes of Mus musculus species complex (house mouse) for biosystematics research was studied in this approach. Recent studies have made use of different mitochondrial genes including NADH dehydrogenase genes, cytochrome b gene, cytochrome oxidase genes, D-loop region and whole mtDNA genome to study the house mouse species. Usage of each of these genome regions has its own advantages and disadvantages. Identification of appropriate genomic regions is very important for molecular biosystematic research. We have shown here that NADH dehydrogenase and Cytochrome oxidase genes (particularly COX2) are especially useful in biosystematics studies and subspecies identification, whereas D-loop region is the best candidate for biogeographic and phylogeographic studies of subspecies of this species efficiency-wise as well as economically. These candidates are introduced considering that the first two gene complexes are highly conserved whereas the latter is well receptive to gaining and preserving the mutations through time.

Mitochondria1 DNA (mtDNA) control region sequences were analyzed to evaluate the population genetic structure of Persian sturgeon (Acipenser persicus) in Caspian Sea. A total of 45 specimens were collected from the different locations of the Caspian Sea. MtDNA control region was amplified using PCR. Direct sequencing was performed according standard method. The results showed that 12 haplotypes were observed between 45 samples in the method. The highest numbers of haplotypes were observed in Sefidroud River in which 3 haplotypes A, B and E among them were specific for the river and were not observed in the other locations. The average haplotype diversity (h) and nucleotide diversity (π) were 0.795±0.037 and 0.0062±0.0046, respectively. The results of FST based on kimura- 2 parameters method and analysis of molecular variance (AMOVA) demonstrated that most variations occurred between samples from Sefidroud River in the south Caspian Sea and that the samples include three distinct populations including Sefidrud, Russia and Azerbaijan (P<0.001). As mtDNA control region is hypervariable segment, this can be provide potential marker for identifying probable populations and for determining their management and conservation units, leading to the useful application of molecular genetics in investigating conservation biology of the Persian sturgeon.

This study documents the flavonoid constituents of seven Salvia species in Iran namely S. atropatana Bunge, S. limbata C. A. Mey, S. sclarea L., S. ceratophylla L., S. multicaulis Vahl., S. hydrangea Dc. ex Benth., and S. eremophila Boiss. The studied species were collected from their natural habitats in Iran and were analyzed for their flavonoid constituents using twodimensional thin layer chromatography with silica gel 60F 254 as solid phase. The purification of flavonoid compounds of each species was carried out using column chromatography with sephadex LH20. Based on the results, 53 flavonoid compounds were identified. The most frequent flavonoid subclasses among seven Salvia species were flavones (35.7%) and the least of these were dihydroflavonoles (5.3%). The most important structural variation observed in flavonoid was related to hydroxylation patterns. Among the identification of flavonoid, eight of them were reported for the first time in Salvia species of Iran. The highest numbers of flavonoid compounds were identified in S. multicaulis and S. hydrangea. It can be concluded that the flavonoid constituents seem to be a suitable indicator in chemotaxonomic studies in Salvia genus.

In this study, the cDNA Growth Hormone (cGH) of the Belugasturgeon (Husohuso) and Russian sturgeon (Acipensergueldenstaedtii) were cloned and sequenced, and phylogenetic relationships were examined using nucleic acid and amino acid sequences. The nucleotide sequence of the Beluga GH has an open reading frame of 645 nucleotides encoding a protein 214 amino acid residues. The signal peptide cleavage site was predicted to be at position 72, yeilding a signal peptide of 24aminoacid residues and a mature peptide of 190 amino acids. The cDNAsequence of the Russian sturgeon was similar to that of the Beluga cGH. The phylogenetic analysis was performed based on amino acid and DNA sequences using the neighbor oining(NJ) and Maximum parsimony (MP) method. Phylogenic trees by the two methods wereidentical in most of the clades with the high bootstrap support, and the topology of amino acid and DNA sequences showed highest similarity with mammalian sequences.

The anionic surfactant sodium dodecyl sulfate (SDS) was degraded by novel strain of Pseudomonas aeruginosa KGS under accession No. JQ328193, which was isolated from car wash wastewater. The purpose of this research was to study different optimization conditions required for enhancing the biodegradation of sodium dodecyl sulfate P. aeruginosa KGS. Influence of different Physicochemical factors such as nitrogen and carbon sources, pH, temperature, inoculation percent and different concentrations of SDS on the biodegradation of SDS were investigated by measuring the degradation rate of SDS using methylene blue active substance (MBAS) method. The optimum conditions determined for the this selected bacterium strain for degradation of SDS were 1.5mM SDS, inoculation percent 7%, pH 7.5, temperature 37°C, ammonium nitrate (nitrogen source) when basal salt medium was supplemented with glucose as a co substrate. This bacterium is able to degrade about 98% of the SDS after 24h of incubation under optimized conditions of biodegradation. The results presented in this research indicate that Pseudomonas aeruginosa is a suitable candidate for SDS biodegradation.

Transverse thin cell layer sections excised from in vitro scales of Lilium ledebourii were cultured on Murashige and Skoog (MS) medium supplemented with various plant growth regulators (PGRs) at different concentrations. Although, bulblets were produced on PGRfree MS medium during organogenesis, addition of 0.25 mg l-1 6-benzyladenine or 5. mg l-1 indole-3-acetic acid to the medium increased the organogenesis response and produced 4.4 bulblets per explants. Two months later, the bulblets were transferred to MS PGRs-free medium. Bulblets were successfully transplanted to the soil after a cold treatment of 8 weeks, with a survival rate of 85%.

Microalgal growth curve, after the exponential phase, shows a stationary phase where algal biomass production is inhibited and remains constant by some factors such as nutrient depletion and intrinsic behavior. The present study is concerned with evaluating effects of the culture medium condition and intrinsic behavior on biomass production by Dunaliella tertiolecta. To this end, effect of pH, nutrient concentration, CO2 (NaHCO3) concentration, possible secreted substances, and cell density on the biomass production by D. tertiolecta were investigated. The results showed that biomass yield can be significantly affected by pH (p<0.01) and nutrient (p<0.05). In a combination of pH and nutrient, the biomass was found to be more influenced by the pH, compared with the nutrients. The results showed a significant interaction between nutrient and NaHCO3 (p<0.05), suggesting that CO2 concentration may limit biomass production only when sufficient nutrients are available. Nutrients concentration and biomass production showed a direct correlation (p<0.05). The rate of reaching the maximum biomass was showed to be increased in higher nutrients concentration; however, the maximum point could not to be affected. The existence of secreted compounds with inhibitory effect on the growth was not observed. The inhibitory effect of the cell density on biomass production can not be confirmed.

Pyricularia oryzae (Tel. Magnaporthegrisea) is currently used as a fungal model for plantmicrobe interaction studies as well as an indicative model for anticancer drug discovery. The present study introduces the optimal condition in which P. oryzae grows and sporulates best on common culture media. We have considered three fungal culture media, i.e. PDA, PCA and WA, based on which P. oryzae sporulation inducers like rice polish, rice extract or rice leaf segments could be added, and evaluated both for vegetative growth and sporulation. Three light regimens, i.e. continuous light, 16.8 hr light/darkness, and continuous darkness were applied in combination with nine synthetic culture media. Mycelial growth was measured after 11 days, but sporulation was tracked on the 10th, 20th, and 30th day after incubation at 26ºC. The findings indicate that PDA culture medium could provide the best medium for P. oryzae vegetative growth, regardless of light condition. However, P. oryzae could sporulate when light was provided either continuously or at intervals. A combination of 16.8 hr light/darkness intervals and adding rice materials to culture media could induce P. oryzae for a better sporulation. RPCA can be used as the best culture medium for P. oryzae in order to obtain a high number of conidia under light alterations. Moreover, aging increases the total number of conidia.

There is a great call for using microbial bio-decaffeination approach to remove caffeine from caffeinated products and industrial wastes. We aimed in this study to screen strains of yeasts which exhibit high caffeine tolerance and to investigate the bio-degradation of caffeine under growth conditions. Sixteen yeast strains were isolated from the cultivated tea soils collected from sites of northern Iran and evaluated for the caffeine tolerance by the agar dilution method. Based on the tolerance efficiency, strain TFS9 was selected and identified as Saccharomyces cerevisiae TFS9 (GenBank accession number KF414526) on the morphological and bioochemical characteristics as well as molecular phylogenetic studies based on amplification the ITS1–5.8S–ITS2 rDNA sequences. The time course of caffeine removal by growing cells of the strain TFS9 in the minimal salt medium containing caffeine as the sole source of carbon was estimated by a decrease in caffeine absorbance using UV-visible spectrophotometer. The concentration of caffeine in the supernatant of the yeast culture medium decreased by 84.8% (from 3.5g/l to 0.53 g/l) after 60h of incubation by using of S. cerevisiae TFS9, without additional optimization process. Results of experimental studies suggest a simple and cost-effective process for the microbial decaffeination of caffeine-containing solutions, and provide a promising approach for developing safe processes that can be used effectively for decaffeination of industrial effluents. The present study provides the first evidence on the caffeine bio-degradation using yeast species of S. cerevisiae.