Shyam Kumar Vootla

Extraction conditions of Antheraea mylitta sericin with high yields and minimum molecular weight degradation

Although the technique for extracting the Bombyx mori sericin has been extensively known, the extraction of sericin from wild-silkworm cocoons is not yet standardized. The aim of this study was to find the optimal conditions for the extraction of sericin from Antheraea mylitta cocoons, with high yields and minimum degradation. We attempted to apply various protocols for the extraction of the A. mylitta sericin (AmS). Among these, we found that the extraction of AmS with a sodium carbonate solution exhibited the highest yield except the conventional soap-alkali extraction. To find the optimal conditions for the AmS extraction with the sodium carbonate, we changed the concentration of sodium carbonate and the treatment time. With an increase in the sodium carbonate concentration and the extraction time, the yield of AmS increased, but the molecular weight (MW) of AmS decreased. Considering the yield, molecular weight distribution (MWD) and amino acid composition of AmS, we suggest that the optimal conditions for the AmS extraction require treatment with 0.02 M sodium carbonate and boiling for 60 min.

Fabrication and Characterization of Conductive Conjugated Polymer-Coated Antheraea mylitta Silk Fibroin Fibers for Biomedical Applications

Conductive polymers are interesting materials for a number of biological and medical applications requiring electrical stimulation of cells or tissues. Highly conductive polymers (polypyrrole and polyaniline)/Antheraea mylitta silk fibroin coated fibers are fabricated successfully by in situ polymerization without any modification of the native silk fibroin. Coated fibers characterized by scanning electron microscopy confirm the silk fiber surface is covered by conductive polymers. Thermogravimetric analysis reveals preserved thermal stability of silk fiber after coating process. X-ray diffraction of degummed fiber diffraction peaks at around 2θ = 20.4 and 16.5 confirms the preservation of the β-sheet structure typical of degummed silk II fibers. This phenomenon implies that both polypyrrole and polyaniline chains form interactions with peptide linkages in degummed fiber macromolecules, without significantly disrupting protein assembly. Fourier transform infrared spectroscopy of coated fibers indicates hydrogen bonding and electrostatic interactions exist between silk fibroin macromolecules and conductive polymers. Resulting fibers display good conductive properties compared to corresponding conjugated polymers. In vitro analysis (live/dead assay) of the behavior of human immortalized keratinocytes (HaCaTs) on coated fibers demonstrates improved cell-adhesive properties and viability after polymers coating. Hence, polypyrrole- and polyaniline-coated A. mylitta silk fibers are suitable for application in cell culture and for tissue engineering, where electrical conduction properties are required.

Green biosynthesis of CuO & Ag–CuO nanoparticles from Malus domestica leaf extract and evaluation of antibacterial, antioxidant and DNA cleavage activities

The reactivity of metallic and bimetallic nanoparticles of copper and silver towards in vitro study has been quantitatively investigated. Here, we report an easy synthesis of nanoparticles by the green method using Malus domestica leaf extract, which acts as a good stabilizing agent. The synthesized CuO and Ag–CuO nanoparticles have shown Surface Plasmon Resonance maxima (SPR) at 335 and 440 nm, respectively. The particles are spherical and crystalline in nature with average sizes between 18 and 20 nm. The Malus domestica leaf-capped nanoparticles have exhibited interesting antibacterial activity with both Gram-positive and Gram-negative bacteria at microgram concentrations. The antioxidant activity of the synthesized nanoparticles has also been measured on the basis of the free radical scavenging activity by the DPPH (1,1-diphenyl 2-picrylhydrazyl) method. Moreover, the DNA cleavage activities of the synthesized nanoparticles have been screened by agarose gel electrophoresis using the E. coli pBR322 plasmid as a target. Hence. owing to the biologically active nature of the synthesized nanoparticles, these greenly synthesized NPs act as a potent therapeutic agent.

Green synthesized multifunctional Ag@Fe2O3 nanocomposites for effective antibacterial, antifungal and anticancer properties

Multifunctional Ag@Fe2O3 nanoparticles were synthesized by employing a green Adathoda vasica leaf extract assisted process. The synthesized nanoparticles were subjected to FTIR, UV-Vis, PXRD and HRTEM measurements for chemical, structural and morphological studies. It is found that vasicine/quinazoline alkaloids present in the extract are responsible for the stability of the nanoparticles. The green synthesized Ag@Fe2O3 nanoparticles showed excellent antibacterial, antifungal and anticancer activity. The green synthesized Ag@Fe2O3 nanoparticles showed better antibacterial activity against Gram positive as well as Gram negative bacteria as compared to previous communications. They have less hazardous effects because of the involvement of the leaf extract in the synthesis of the nanoparticles rather than hazardous chemicals. The present investigation points out that the synthesized nanoparticles are promising in targeted drug delivery systems, bactericides and fungicides, and may be used for magnetic hyperthermia cancer therapy.

Rapid Detection of Infectious Flacherie Virus of the Silkworm, Bombyx mori, using RT-PCR and Nested PCR

Abstract In this study, a method for detection of an ssRNA viral pathogen that causes viral flacherie in the silkworm, Bombyx mori (L.) (Lepidoptera: Bombycidae), was used for the detection of B. mori infectious flacherie virus (BmIFV). A combination of nested and reverse transcriptase polymerase chain reaction was used for detection. Although BmIFV has been reported in almost all the sericultural regions of the world, there had been no reports of BmIFV incidence in India. Therefore, the confirmation of the presence of BmIFV in Karnataka, India, is of great significance. The present method is advantageous because it can be used to detect the virus by using samples from infected midgut tissues, thus simplifying and avoiding laborious genome isolation procedures. This method could help in early detection of BmIFV disease pathogens and help reduce crop losses.

Pathogen-Driven Proteomic Changes in Hemolymph of Nuclear Polyhedrosis Virus-Infected Silkworm Bombyx mori L.

Viral infections are distinct in the capacity of the viruses to overtake the host’s protein synthesis machinery and regulate it for the viral replication. Interaction and infection process of BmNPV in its host Bombyx mori is an important step to understand host-pathogen interaction studies. In present research work, we have screened the BmNPV isolate from the grasserie-infected silkworms from rearing fields of Central Karnataka, India. Isolation, purification, and characterization of the BmNPV virus were done by sucrose density gradient centrifugation, scanning electron microscopy, and SDS-PAGE of the occlusion bodies (OBs). Comparative proteomic analysis revealed drastic up- and downregulation of several proteins in control and infected silkworms. The role of various proteins in comparison with reported proteins responsible for disease infection was elucidated.

Blastobotrys bombycis sp. nov., a d-xylose-fermenting yeast isolated from the gut of the silkworm larva Bombyx mori

The gut of insects harbors a yeast community that is still poorly understood. Here, a novel species of the ascomycetous genus Blastobotrys is proposed based on a yeast strain isolated from the larval gut of the silkworm Bombyx mori (Order Lepidoptera). The novel species is closely related to Blastobotrys aristata and Blastobotrys elegans on the basis of the results of molecular phylogenetic analyses. A preliminary screening revealed that it produces 1.5 g l-1 ethanol by fermenting 5 % d-xylose. The novel species, that represents the first report, to our knowledge, of yeast isolation from silkworms, is described as Blastobotrys bombycis sp. nov. (type strain RAAB001T=CBS 15274T=PYCC 8105T=MCC 1427T; MycoBank accession number MB 825095).

Self-assembled Nanoparticles Prepared from Tasar Antherea mylitta Silk Sericin

Silk sericin is the gum-like protein surrounding the fibroin in silk fibers, and generally it is removed during the fiber processing to produce fabrics. Like other silk proteins, the silk of tasar silkworms is also composed of sericin and fibroin. In this study tasar silk sericin was extracted and was confirmed to be a 70 KDa protein by SDS PAGE. The use of sericin in the field of biomedical applications has increased their use for various purposes, the extracted silk sericin was pegylated with activated PEG (MW 5000) and the conjugated product was characterized by FT-IR, 1H NMR, CD, DSC, XRD, and AF TEM and self-assembled nanoparticles were prepared.