Bacillus-based nano-bioformulations for phytopathogens and insect–pest management

Abstract Background Recent concerns linked with the application of chemical pesticides and the increasing necessity of low inputs sustainable agriculture have put the use of microbial biocontrol agents and bio-pesticides to the forefront for their application against plant pathogens and insect–pest management. Results This review tended to scrutinize the prospects of microbial biocontrol agents and microbes-based nano-formulations against plant diseases and for pest management with emphasis on bacteria-based nanoparticles, especially derived from Bacillus species. It also tended to discuss the probable mechanism of action and effect on plant growth along with its prospects in a brief manner. Conclusion The use of microbial biocontrol agents offers effective, eco-friendly, and long-lasting management of plant diseases. The employment of nanotechnology in the field of biopesticides has emerged as a promising solution. Nano-biopesticides in the form of biologically derived active pesticides or compounds integrated as nanoparticles and integrated into a suitable polymer have application in insect–pest management. </jats:sec

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Not AvailableAn efficient somatic embryogenesis protocol for plantlet regeneration of the commercially valuable, and nutritionally important, crop guava (Psidium guajava L.) has been established. The immature zygotic embryos were targeted as an explant source for inducing somatic embryogenesis and plant regeneration, using four commercial cultivars (Allahabad Safeda, Lalit, Sardar and Shweta). The plantlets regenerated were assessed for genetic fidelity using random amplified polymorphic DNA (RAPD), inter simple sequence repeats (ISSR) and simple sequence repeat (SSR) molecular markers. A total of 2171 scorable bands were obtained using RAPD, ISSR or SSR, ranging from 300–3500, 250–3000 and 150–280 bp, respectively. No polymorphism was observed among the somatic embryogenesis regenerated plants, compared with respective donor mother plants. The profiles generated based on the three marker systems were found to be highly uniform and approximately 99% bands were monomorphic. This high degree of genetic uniformity (as assessed using the markers) in the somatic embryogenesis regenerated plants indicates genomic stability was maintained through the regeneration protocol. The somatic embryogenesis regenerated plants were hardened and transferred to the field for acclimatization, of which 80% plantlets survived, with all being phenotypically similar to the donor mother plants. We conclude that the RAPD, ISSR and SSR markers were informative and potentially useful in confirming the uniformity assessment of somatic embryogenesis regenerated plants.Not Availabl

Development and Application of PP-CNT Composite for Hummingbird Inspired MAV Flapping Wings

Micro Air Vehicles (MAVs) are small unmanned aircrafts which have a maximum size limit of 150 mm in any direction. They can be used for surveillance, reconnaissance, targeting, etc. To perform such missions, MAVs are required to hover. Hummingbirds, having excellent flight characteristics (such as hovering, ability to fly in any direction, ability to produce a reverse camber during upstroke for generating lift in both up-down strokes), have been chosen as the bio-inspiration for wing development. Wings are required to be light, strong and fatigue resistant, to be able to properly flap during flight. Therefore, wing-material becomes a crucial component. An optimization analysis, on the basis of density and fundamental frequency values obtained through Ansys, was done for selecting the wing material. Polypropylene (PP) was observed to have desired properties such as light weight, flexibility, strength, fatigue resistance, good heat and chemical resistance etc. Mixing Carbon Nano Tubes (CNTs) with PP can further increase the strength significantly, making it more suitable for large amplitude flapping. The PP-CNT composites were developed using solution casting method. The films were characterized mechanically (using UTM). The wings were characterized by their structural dynamic properties. The modal analysis of wings was done to obtain natural frequencies and mode shapes. The analysis was aimed to get the fundamental mode in the flapping range (8-15 Hz) of hummingbirds, as resonance increases efficiency. It was also done inside vacuum chamber to observe the effect of air on the natural frequency and modes. The Ansys results were compared with the experiments in vacuum for validation of experimental results. Damping coefficient of wings was also determined. In the end, bio-mimicking of hummingbird wing was also tried by doing some material and structural advancements in the wings

Deformation Analysis of a Hummingbird Inspired MAV Flapping Wing using Digital Image Correlation

Flapping wing micro air vehicles (MAVs) have the advantage of being able to fly at slow speeds and have high maneuverability. The design of a flapping wing MAV inspired by birds presents many technical challenges because birds as natural fliers exhibit higher efficiency than any man made flapping wing structure. Thus, the structure and motion of bird wings provide a starting point for the study of flapping wing MAV. In order to compare the deflections of the fabricated wings with the complex mechanism of the bird wings, it is required to quantify these deflections. Both the bird wings and the fabricated wings are very light weight and, therefore extremely light weight sensors or non-contact methods are required for the measurements of the deflections. Digital image correlation (DIC) provides one such option. DIC is an optical noncontact method used to acquire displacements. A simple two dimensional DIC code has been developed and validated in this work. Design and fabrication of wings is based on the hummingbirds. A 3D tapered wing design was developed and used for development of mold. This mold was used for fabrication of flexible polypropylene wings. For flapping motion measurements of wings, a simple slider-crank mechanism was designed to generate an oscillatory motion using brushless DC motors and Arduino Board. For modal analysis, an electrodynamic shaker was used to vibrate the wing with patterns stuck over its surface at its natural frequencies and captured the motion using a high speed camera. The captured images were analyzed using the developed DIC code and mode shapes for 1st and 2nd modes were obtained. For capturing the motion of a wing, a high speed camera mounted on a suitably designed stand was used. The validation of modal analysis was done using commercial finite element analysis software Ansys