Phosphorus forms of the surface sediment in the Iranian coast of the southern Caspian Sea

Sediments from the southern Caspian Sea, located in Iranian coast were examined on the basis of P-fractionation (five forms of phosphorus) by a sequential extraction scheme. Ninety-six surface sediment samples (for each season with triplicate) were collected from eight sampling transects in 10 and 100 m depths during summer and winter in 2010-2011. The result indicated that the most abundant forms of phosphorus were calcium bound phosphorus. Relative abundance of other forms of phosphorus follow the order: organic-P>Fe-P>Al-P>Absorbed-P. The loosely absorbed phosphorus represented <1% of the sedimentary inorganic phosphorus, while the Fe/Al phosphorus ranged 5–6%.The calcium bound phosphorus showed considerable contribution (88%) to the sedimentary inorganic P-loads

A gene expression study on strains of Nostoc (Cyanobacteria) revealing antimicrobial activity under mixotrophic conditions

Cyanobacteria are well known for their production of a multitude of highly allelopathic compounds. These products have features such as incorporation of non-proteinogenic amino acids which are characteristics of peptides biosynthesized by non-ribosomal peptide synthetases (NRPSs). Some of these peptides have acetate-derived moieties, suggesting that their biosynthesis also involves polyketide synthases (PKSs). Among the photosynthetic microorganisms, cyanobacteria belonging to the genus Nostoc are regarded as good candidates for producing biologically active secondary metabolites. Aiming at the maximization in the production of natural product, we compared autotrophic, and mixotrophic growth at high light intensity of two Nostoc species in relation to the production of bioactive compounds with the antimicrobial activity at different source of sugar. Glucose was shown to be the best substrate for the production of high natural product when compared with sucrose. Also, the rate of biomass production and antimicrobial activity was reaching ~2.0 to 2.5 and ~1.5 times greater than that of the autotrophic and sucrose grown cultures, respectively. Also, we conduct a combined NRPSs and PKSs polymerase chain reaction (PCR). The sequences presented in this study was deposited in GenBank and had accession numbers JF795278 and JF795279 (NRPS A domains) and JF795280 and JF795281 (PKS KS domains). Computer modeling and phylogenetic analysis was conducted to predict the putative amino acid recognized by the unknown adenylation domain in the NRPS sequences. This study highlights the importance of environmental and nutrimental factors in maximization of antibiotic production of two Nostoc species.Keywords: Peptide synthetase gene, polyketide synthase gene, Nostoc, secondary metabolites, mixotrophic condition

Molecular characterization of polymorphisms among Pseudomonas aeruginosa strains isolated from burn patients' wounds

Pseudomonas aeruginosa is one of the most common reasons for nosocomial infections. Given the high morbidity and mortality, as well as the cost of management, particularly in developing countries, burn injuries are considered important health concerns. Owing to the increased rate of resistance against antibiotics, this study aimed to isolate Pseudomonas aeruginosa strains from burn patient's wounds by analyzing antibiotic susceptibility and genetic profiling. In this regard, we explored the relationship between the nucleotide sequence and antibiotic susceptibility. In this cross-sectional study, 107 isolates of P. aeruginosa were collected from a major burn center in Tehran, Iran. The isolates were characterized with standard biochemical tests and examined by applying the Disk Diffusion method to find the patterns of sensitivity, and their genetic relationship was revealed by RAPD-PCR method. According to the antibiogram results, most of the isolates were resistant to 3 or more antibiotics tested and the most sensitivity was related to the Colistin antibiotic. RAPD-PCR method revealed a high polymorphism among P. aeruginosa isolates in Tehran. There was no significant association between the genotype groups and antibiotic susceptibility profiles. We evaluated the pattern of resistance to pathogenic organisms and identified multi-drug resistant organisms. Currently, Colistin antibiotic is the most suitable treatment option for burned patients. RAPD-PCR is a genotyping method with high efficiency for typing and categorizing different isolates of MDR-P. aeruginosa. © 2020 Biotechnology; Genetics; Microbiology; Molecular Biology; Infectious disease; Pseudomonas aeruginosa; RAPD-PCR; Nosocomial infections; Burn patients. © 202

Optimization of growth media components for polyhydroxyalkanoate (PHA) production from organic acids by Ralstonia eutropha

We employed systematic mixture analysis to determine optimal levels of acetate, propionate, and butyrate for cell growth and polyhydroxyalkanoate (PHA) production by Ralstonia eutropha H16. Butyrate was the preferred acid for robust cell growth and high PHA production. The 3-hydroxyvalerate content in the resulting PHA depended on the proportion of propionate initially present in the growth medium. The proportion of acetate dramatically affected the final pH of the growth medium. A model was constructed using our data that predicts the effects of these acids, individually and in combination, on cell dry weight (CDW), PHA content (%CDW), PHA production, 3HV in the polymer, and final culture pH. Cell growth and PHA production improved approximately 1.5-fold over initial conditions when the proportion of butyrate was increased. Optimization of the phosphate buffer content in medium containing higher amounts of butyrate improved cell growth and PHA production more than 4-fold. The validated organic acid mixture analysis model can be used to optimize R. eutropha culture conditions, in order to meet targets for PHA production and/or polymer HV content. By modifying the growth medium made from treated industrial waste, such as palm oil mill effluent, more PHA can be produced.Malaysia. Ministry of Science, Technology and Innovation (MOSTI

Evaluation of antioxidant activity of natural product compounds from Platycladus orientalis leaves

Background and objectives: Natural product compounds of plants have been used since ancient times and in folklore medicine for the treatment of many diseases and illnesses. Oxygen-centered free radicals and other reactive oxygen species, which are continuously, produced in vivo, result in cell death and tissue damage. Oxidative damage caused by free radicals may be related to aging and diseases, such as arteriosclerosis, diabetes, cancer, and cirrhosis. Although almost all organisms possess antioxidant defense and repair systems that have evolved to protect them against oxidative damage, these systems are insufficient to prevent the damage entirely. However, antioxidant supplements from plants may be used to help the human body reduce oxidative damage. Platycladus orientalisis an ornamental conifer of the cypress family. The leaves of Platycladus orientalis have been used in medicine for treatment of gout, rheumatism, diarrhea and chronic tracheitis. This study has aimed at evaluating the in vitro antioxidant activity of extracts of Platycladus orientalisleaves, in comparison with commercially available antioxidants. Methods:The antioxidant activity was assessed by reducing power, total phenolics content, DPPH radical scavenging activity and RBC hemolysis. Results: The results showed that both the water and the ethanol extracts exhibited strong total antioxidant activity. More statistical data analysis is in process. Conclusion: This result may be a major reason for introducing Platycladus orientalisas a good scavenger of hydrogen peroxide, superoxide, and free radicals. However, the components responsible for the antioxidative activity of Platycladus orientalisleaves are currently unclear. Therefore, it is suggested that further work could be performed on the isolation and structural identification of the antioxidant compounds from Platycladus orientalisleaves and to evaluate its in vivo effects