ISOLATION AND SCREENING OF NOVEL STREPTOMYCES FROM SEDIMENTS OF BAY OF BENGAL NEAR SRIKAKULAM COAST

Objective: The Objective of this research is to isolate and screen potent antibiotic producing actinomycetes from unexplored regions of Bay of Bengal Near Srikakulam Coast.Methods: The isolation and screening were done on starch casein agar media. Antimicrobial activity screening was done using cross streak method and agar diffusion method. Further, Morphological characterization of the isolate was done using Scanning electron Microscopy (SEM-JSM 6610). Further, the cultural characterization of the isolates was done using standard protocols.Results: A total of sixty-eight isolates of Actinomycetes were collected from marine sediments of coastal line of Srikakulam district of Andhra Pradesh, which is one of the longest coastal lines of Andhra Pradesh. Due to its longest coastal line and geographical distribution, there are promising chance of diversity of the microorganisms and antibiotic producing potential. Each isolate was tested against various bacteria. Among all the isolates twelve isolates were promising and showed good antimicrobial activity. Within twelve isolates the isolate A-10 was very promising and showed antibiotic potential against most of the tested bacteria. This isolate appears to produce high anti-bacterial compounds on potato dextrose agar and nutrient agar medium respectively by using the agar diffusion method. The potent Actinomycete A-10 was further characterised by morphological methods consist of macroscopic and microscopic methods. The mycelium structure, colour and arrangement of conidiophores were observed through the oil immersion (100X). The strain was grown on Starch-Casein agar medium for morphological study using Scanning Electron microscopy. Scanning Electron micrographs of the strain A-10 results that the spore chain was straight and with more than 20 spores per chain. The spores are cylindrical in shape and had a smooth surface. Whirls, sclerotic granules, sporangia and flagellate spores were not observed. Further various biochemical tests performed for the identification of potent isolates are as follows: Melanin reaction, H2S production, tyrosine reaction, starch hydrolysis, casein hydrolysis, gelatin hydrolysis, milk coagulation and peptonization, nitrate reduction, temperature range of growth, pH tolerance and cell wall type by comparing all these results with the Bergey's manual of Determinative Bacteriology and the organisms were identified. The isolate was identified as Streptomyces sp.Conclusion: Thus the result of antibacterial screening represents that the coastal area of Srikakulam is a potential source of antibiotic producing actinomycetes. Further the phylogenic tree construction and purification of the antibiotic principle from A-10 were under investigation.Keywords: Actinomycetes, Marine Sediments, Starch-Casein agar, SE

Stabilizing ultrathin Silver (Ag) films on different substrates

This paper reports an effective method of stabilizing ultrathin Silver (Ag) films on substrates using a filler metal (Zn). Ag films with a thickness < 15 nm were deposited by DC magnetron sputtering above a Zn filler metal on glass, quartz, silicon and PET (polyethylene terephthalate) substrates. Zinc is expected to partially or fully fill the roughness associated with the substrates. The Zn filler material and ultrathin Ag film form a 3-D augmented atomically chemically graded interface. 3-D interfaces have smoothly varying chemistry. The ability of Zn to partially or fully fill the substrate roughness improves the adhesion of Zn along with the Ag to the substrate. Also, Zn acts as a barrier layer against the diffusion of Ag into the substrate. This technique leads to ultrathin Ag films with low sheet resistance (~ 3 {\Omega}/Sq.), low mean absolute surface roughness (~1 nm), good optical transparency (~ 65 %), better stability and compatibility with the environment. The results indicate significant potential for applying stable ultrathin Ag film/electrode as a practical and economically feasible design solution for optoelectronic (transparent and conductive electrodes for solar cells and LEDs) and plasmonic devices. This film shows good conductivity, transparency, stability, and flexibility.Comment: 16 pages,8 figures, 3 table

Experimental Insights into the Coupling of Methane Combustion and Steam Reforming in a Catalytic Plate Reactor in Transient Mode

The microstructured reactor concept is very promising technology to develop a compact reformer for distributed hydrogen generation. In this work, a catalytic plate reactor (CPR) is developed and investigated for the coupling of methane combustion (MC) and methane steam reforming (MSR) over Pt/Al2O3-coated microchannels in cocurrent and counter-current modes in transient experiments during start-up. A three-dimensional (3D) computational fluid dynamics (CFD) simulation shows uniform velocity and pressure distribution profiles in microchannels. For a channel velocity from 5.1 to 57.3 m/s in the combustor, the oxidation of methane is complete and self-sustainable without explosion, blow-off, or extinction; nevertheless, flashbacks are observed in counter-current mode. In the reformer, the maximum methane conversion is 84.9% in cocurrent mode, slightly higher than that of 80.2% in counter-current mode at a residence time of 33 ms, but at the cost of three times higher energy input in the combustor operating at ∼1000 °C. Nitric oxide (NO) is not identified in combustion products, but nitrous oxide (N2O) is a function of coupling mode and forms significantly in cocurrent mode. This research would be helpful to establish the start-up strategy and environmental impact of compact reformers on a small scale

Quantitative analysis of gallstones in Libyan patients

Gallstone disease is one of the major surgical problems in the Libyan population; it is probably related to diet, especially excessive consumption of meat. The study was conducted to determine the composition of gallstones and their possible etiology in a Libyan population. The chemical composition of gallstones from 41 patients (six males and 35 females) was analyzed. The stones were classified into cholesterol, pigment, and mixed stones (MS). Cholesterol stones (CS) showed a significantly higher cholesterol content than pigment stones (PS) (p=0.0085) though not significantly higher than MS. Their phospholipid content and inorganic phosphates were higher than in the other types of stones and oxalate content was significantly elevated in comparison with MS (p=0.0471). In MS, the cholesterol, bile acids, and bilirubin were intermediate between cholesterol and PS, whereas triglycerides were significantly more than PS (p=0.0004). Bilirubin (0.0001) and bile acids (p=0.0009) were significantly higher than CS (p=0.0001). However, they contained the lowest amounts of sodium, potassium, magnesium, and oxalate. In PS, bilirubin (p=0.0001) was significantly higher than both groups. Bile acid content was significantly higher than CS (p=0.0001) but not significantly more than MS. They showed the highest values of calcium, sodium, potassium, magnesium, and chlorides compared to the other types of stones. High levels of cholesterol in stones and dyslipidemia associated with mixed as well as cholesterol gallstones suggest an etiological association and efforts to reduce dietary fat among the Libyan population may lead to decreased cholesterol and mixed gallstones

Photocrosslinkable gelatin hydrogels modulate the production of the major pro-inflammatory cytokine, TNF-α, by human mononuclear cells

Hydrogels are an attractive class of biomaterials in tissue engineering due to their inherently compatible properties for cell culture. Gelatin methacryloyl (GelMA) has shown significant promise in the fields of tissue engineering and drug delivery, as its physical properties can be precisely tuned depending on the specific application. There is a growing appreciation for the interaction between biomaterials and cells of the immune system with the increasing usage of biomaterials for in vivo applications. Here, we addressed the current lack of information regarding the immunogenicity of photocrosslinked GelMA. We investigated the ability of human mononuclear cells to mount inflammatory responses in the context of a GelMA hydrogel platform. Using lipopolysaccharide to stimulate a pro-inflammatory immune response, we found tumour necrosis factor-α (TNF-α) expression was suppressed in GelMA culture conditions. Our findings have important implications on the future use of GelMA and highlight the significance of investigating the potential immune-modulatory properties of biomaterials

Janus Nanoparticles for Dual Wavelength Surface Enhanced Raman Scattering Applications

Plasmonic nanostructures have been used to enhance Raman scattering by the virtue of surface plasmon resonances. This method of surface enhanced Raman spectroscopy (SERS) has paved the way for these plasmonic nanostructures to be used as potential SERS substrates in applications like bio-sensing, diagnostics and other applications. In order to optimize the SERS enhancement, the plasmon resonance of the nanostructures needs to be tuned. The usage of alloy nanoparticles has been an efficient method to achieve this. In this paper we study Ag-Cu alloy nanoparticles with Janus morphology and explore the possibility of tuning the plasmon resonance in order to utilize the nanostructures for dual wavelength SERS applications. © 2022 IEEE

Successful Isolation of Burkholderia pseudomallei from Soil by Extended Incubation of Ashdown’s Agar: A Cross-sectional Study

Introduction: Melioidosis is an infectious disease of humans and animals caused by an environmental saprophyte Burkholderia pseudomallei. Although the organism is associated with soil and water, environmental isolation is rarely successful which could be due to the existence of viable but non culturable forms. Aim: To isolate B. pseudomallei from the soil to detect the environmental presence of this organism in and around Puducherry, India. Materials and Methods: A descriptive cross-sectional study was carried out from July 2018 to January 2021 at Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India. A total of 473 soil samples were collected from areas surrounding the residence and workplaces of seven cultureproven melioidosis cases, from Puducherry and three districts of Tamil Nadu (Cuddalore, Nagapattinam and Villupuram) during the dry and wet seasons. Soil samples were enriched in Ashdown’s broth and cultured on Ashdown’s agar. The plates were incubated at 37°C and examined daily for seven days with a further extended period of incubation till the tenth day for samples that did not show growth. Suspected isolates were subjected to Vitek 2 system for biochemical identification. Confirmation of the isolates was carried out by antigen detection and Polymerase Chain Reaction (PCR). Results: From 473 soil samples processed, bacteria with colony morphology similar to B. pseudomallei were isolated in 56 (11.83%) samples. Only one isolate, which was detected on the tenth day of incubation was confirmed as B. pseudomallei using antigen detection and PCR. This sample was collected during the wet season (December 2020) from Endur, in the Villupuram district of Tamil Nadu, India. Conclusion: The study findings highlight the importance of extended incubation of culture plates at 37°C for up to ten days to improve the chances of isolation from the soi