Actinobacteria: Potential Candidate as Plant Growth Promoters

Plant growth enhancement using plant beneficial bacteria has been viewed in the sustainable agriculture as an alternative to chemical fertilizers. Actinobacteria, among the group of important plant-associated bacteria, have been widely studied for its plant growth promotion activities. Actinobacteria are considered as a limelight among agriculturists for their beneficial aspects toward plants. They are naturally occurring spore-forming bacteria inhabiting the soil and known for their plant growth-promoting and biocontrol properties. The mechanisms behind these activities include nitrogen fixation, phosphate solubilization, siderophore production, and other attributes such as antifungal production of metabolites, phytohormones, and volatile organic compound. All these activities not only enhance the plant growth but also provide resistance in plants to withstand unfavorable conditions of the environment. Hence, this chapter emphasizes on the plant growth traits of actinobacteria and how far it was studied for enhanced growth and bio-fortification

Antibacterial, Structural and Optical Characterization of Mechano-Chemically Prepared ZnO Nanoparticles.

Structural investigations, optical properties and antibacterial performance of the pure Zinc Oxide (ZnO) nanoparticles (NPs) synthesized by mechano-chemical method are presented. The morphology, dimensions and crystallinity of the ZnO NPs were controlled by tweaking the mechanical agitation of the mixture and subsequent thermal treatment. ZnO nanoparticles in small (< 20 nm) dimensions with spherical morphology and narrow size distribution were successfully obtained after treating the mechano-chemically prepared samples at 250°C. However, higher temperature treatments produced larger particles. TEM, XRD and UV-Vis spectroscopy results suggested crystalline and phase pure ZnO. The NPs demonstrated promising antibacterial activity against Gram negative foodborne and waterborne bacterial pathogens i.e. Enteropathogenic E. coli (EPEC), Campylobacter jejuni and Vibrio cholerae as well as Gram positive methicillin resistant Staphylococcus aureus (MRSA), thus potential for medical applications. Scanning electron microscopy and survival assay indicated that most probably ZnO nanoparticles cause changes in cellular morphology which eventually causes bacterial cell death

Comparative Analysis on the Structure and Properties of Iron-Based Amorphous Coating Sprayed with the Thermal Spraying Techniques

Iron-based amorphous coatings are getting attention owing to their attractive mechanical, chemical, and thermal properties. In this study, the comparative analysis between high-velocity oxy-fuel (HVOF) and atmospheric plasma (APS) spraying processes has been done. The detailed structural analysis of deposited coatings were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Mechanical and electrochemical properties were investigated by using micro-Vickers hardness testing, pin-on-disc tribometry and potentiodynamic analysis. The microstructure comparison revealed that HVOF-coated samples had better density than that of APS. The porosity in APS-coated samples was 2 times higher than that of HVOF-coated samples. The comparison of tribological properties showed that HVOF-coated samples had 3.9% better hardness than that of coatings obtained via APS. The wear test showed that HVOF-coated samples had better wear resistance in comparison to APS coatings. Furthermore, the potentiodynamic polarization and electrochemical impedance spectroscopy showed that the HVOF-coated samples had better corrosion resistance in comparison to APS-coated samples

Antibacterial potential (minimum inhibitory concentration) of synthesized ZNO nanoparticles

<p>Antibacterial potential (minimum inhibitory concentration) of synthesized ZNO nanoparticles</p

SEM images of E. coli and S.aureus.

<p>(a) E. coli cells untreated (b) E. coli cells treated with ZnO nanoparticles for 4 h. (c) S.aureus cells untreated (d) S.aureus cells treated with ZnO nanoparticles for 4 h.</p