Nachimuthu Ramesh

Analysis of Stress Responsive Genes in Capsicum for Salinity Responses

Aims: This study is an endeavor to gain proper understanding about salt tolerance mechanism in plants; an attempt was made to characterize the differential expression of stress responsive genes, sodium potassium content proline content in three capsicum cultivars having different salt sensitivity level. Place and Duration of Study: School of Bio Sciences and Technology, VIT University, Vellore of India between June 2013 to May 2014. Methodology: Capsicum cultivars (salt tolerant, salt moderate sensitive and salt susceptible) were treated with different concentration of NaCl such as 25mM, 50mM, 100mM, 150mM and 200mM. Gene expression studies under different salt treatment were done for the following genes: osmotic adjustment (CaPROX1), osmotin like protein (CaOSM1), aquaporin (CaPIP2), dehydrin responsive gene (CaDREBLP1), ring domain zinc finger protein gene (CaKR1), membrane protein (CaChi2), endoplasmic reticulum ubiquitine ligase (CaRMa1H1) and cell death repressor (CaBI1). Proline Original Research Article Maurya et al.; ARRB, 6(1): xxx-xxx, 2015; Article no.ARRB.2015.064 67 content and sodium and potassium ion content also measured. Results: The result indicated that genes CaDREBLP1, CaRMa1H1, CaKR1, CaOSM1 were up regulated while CaPROX1, CaPIP2 genes were down regulated under salt stress. But no significant difference was noticed in gene expression level of CaBI1 and CaChi 2 gene. Conclusion: The higher gene expression level of stress responsive genes viz. CaDREBLP1, CaRMa1H1, CaKR1, CaOSM1 may involved in different level of salt tolerance among selected cultivars. Thus differential transcript modulation of these genes in capsicum cultivars indicates their role lending the salt tolerance in salt tolerant cultivar than sensitive.

Role of biofilm-specific antibiotic resistance genes PA0756-0757, PA5033 and PA2070 in Pseudomonas aeruginosa

To evaluate the presence of biofilm-specific antibiotic-resistant genes, PA0756-0757, PA5033 and PA2070 in Pseudomonas aeruginosa isolated from clinical samples in Tamil Nadu. For this cross-sectional study, 24 clinical isolates (included pus, urine, wound, and blood) were collected from two diagnostic centers in Chennai from May 2015 to February 2016. Biofilm formation was assessed using microtiter dish biofilm formation assay and minimal inhibitory concentration (MIC) and minimal bactericidal concentrations (MBC) were determined for planktonic and biofilm cells (MBC assay). Further, PCR amplification of biofilm-specific antibiotic resistance genes PA0756-0757, PA5033 and PA2070 were performed. Biofilm formation was found to be moderate/strong in 16 strains. MBC for planktonic cells showed that 4, 7, 10 and 14 strains were susceptible to gentamicin, ciprofloxacin, meropenem and colistin respectively. In MBC assay for biofilm cells (MBC-B), all the 16 biofilm producing strains were resistant to ciprofloxacin and gentamicin whereas nine and four were resistant to meropenem, and colistin respectively. The biofilm-specific antibiotic-resistant genes PA0756-0757 was found in 10 strains, 6 strains with PA5033 and 9 strains with PA2070 that were found to be resistant phenotypically. This study highlighted the importance of biofilm-specific antibiotic resistance genes PA0756-0757, PA5033, and PA2070 in biofilm-forming P. aeruginosa.

Isolation, characterization and in vivo efficacy of Escherichia phage myPSH1131

Phage therapy is the use of lytic bacteriophages to cure infections caused by bacteria. The aim of this study is to isolate and to characterize the bacteriophages against Escherichia coli isolated from clinical samples. For isolation of bacteriophages, water samples were collected from the Ganges River, and phage enrichment method was followed for phage isolation. Microbiological, genomic and lyophilization experiments were carried out to characterize the bacteriophage. Galleria mellonella was used to study the potential of phages against E. coli infection. Escherichia phage myPSH1131 belonging to Podoviridae family and found to have broad host range infectivity (n = 31) to infect Enterohemorrhagic E. coli (n = 9), Enteropathogenic E. coli (n = 6), Enterotoxigenic E. coli (n = 3), Enteroaggregative E. coli (n = 3), Uropathogenic E. coli (n = 9) and one unknown E. coli. The genome size is 76,163 base pairs (97 coding regions) and their genes show high similarity to SU10 phage. Lyophilization studies showed that the use of 1M sucrose, 2% gelatin and the combination of both 0.5M sucrose plus 1% gelatin could restore phage viability up to 20 months at 4°C. For in vivo studies, it was observed that a single phage dose can reduce the E. coli infection but to achieve 100% survival rate the infected larvae should be treated with three phage doses (20 μL, 103 PFU/mL) at 6 hours interval. The characterized Escherichia phage myPSH1131 was found to have broad host range activity against E. coli pathogens and in vivo studies showed that multiple doses are required for effective treatment.

Nanomaterials: Classification, Biological Synthesis and Characterization

Nanomaterial research has recently gained importance due to prospective applications in human life and environment. However, scientific research on nano- and micro-sized materials has reached a saturation state. As a result, researchers planning to further develop nanomaterials, need an outlook on recent advances in synthesis, classification and characterization of nanomaterials. There is a need in particular for an overview of synthesis using biological materials namely bacteria, fungi, yeast, and plants, in order to design eco-friendly nanomaterials. Methods used to characterize these synthesized nanoparticles must also be reviewed to suggest the appropriate techniques in terms of spectroscopic and microscopic methods to study the physio-chemical properties of nanomaterials. Here we review the nature, types and synthesis of nanomaterials, with a detailed evaluation on biological synthesis. We also discuss in detail nanoparticle production by microorganisms including bacteria, fungi and yeasts. This chapter also provides updates on currently available techniques used to characterize nanoparticles.