Chitosan/pullulan based films incorporated with clove essential oil loaded chitosan-ZnO hybrid nanoparticles for active food packaging.

Herein, we developed clove essential oil (CEO) loaded Chitosan-ZnO hybrid nanoparticles (CS-ZnO@CEO (CZC NPs)) integrated chitosan/pullulan (CS/PL) nanocomposite films. SEM images revealed a homogenous distribution of CZC NPs with minimum aggregation in nanocomposite films. The incorporation of CZC NPs led to enhanced tensile strength (~39.82%), film hydrophobicity (~35.36%), UV light blocking ability, water vapor barrier (~84.64%), and oxygen barrier (~57.66%) compared to the bare CS/PL film and overall migration limit of CPCZC films were found below the permitted limit of 1000 µg/dm2. Besides, incorporation of CZC NPs into the CS/PL films enhanced antioxidant activity and showed strong antibacterial activity against P. aeruginosa, S. aureus, and E. coli. Also, the CPCZC films displayed potential to extend the shelf-life of chicken meat by up to 5 days when stored at 8 ± 2 °C. These results suggest that the prepared CPCZC films acquire the ideal prerequisites for potential active packaging materials.

Preparation and physicochemical assessment of bioactive films based on chitosan and starchy powder of white turmeric rhizomes (Curcuma Zedoaria) for green packaging applications.

In the current study, the bioactive films of chitosan/white turmeric (CH/WT) were prepared by employing solvent casting technique and analyzed their physicochemical and biological properties for active packaging applications. The successful inclusion of white turmeric into the chitosan matrix is confirmed by Fourier Transform Infrared Spectroscopy. Due to the presence of hydrogen bonding interaction, the active films exhibited good tensile properties, smooth surface morphology, miscibility, water resistance and UV barrier properties. The incorporation of white turmeric reduced the water vapour transmission rate and oxygen permeability (p < 0.05) in contrast with pristine film. The prepared blend films revealed soil degradation rate more than 60% within 15 days. Furthermore, the blend films exhibited lesser water solubility, moisture content and swelling index after addition of white turmeric to chitosan (p < 0.05). The prepared films revealed extensive antimicrobial activity against gram positive and gram negative bacteria. The antioxidant activity and total phenolic content were improved upon the incorporation of white turmeric. Moreover, the oil absorption rate of the blend films was decreased by 46% in comparison with pristine film. Overall, white turmeric incorporated chitosan films were employed as a green packaging material to extend the shelf life of the foodstuff.

Smart biodegradable films based on chitosan/methylcellulose containing Phyllanthus reticulatus anthocyanin for monitoring the freshness of fish fillet.

The current work aims to prepare biologically active and pH responsive smart films based on Chitosan (CS)/Methylcellulose (MC) matrix integrated with Phyllanthus reticulatus (PR) ripen fruit anthocyanin. The prepared smart films (CMPR) were fabricated through a cost-effective solvent casting technique. The existences of secondary interactions were confirmed by the FT-IR analysis. The smooth SEM images revealed the miscibility and compatibility of the CS/MC matrix with PR anthocyanin. The incorporation of PR anthocyanin significantly blocked the UV light transmission of the CS/MC films while slight decrease in the transparency was observed. The water solubility, moisture retention capacity, and water vapor transmission rate were significantly enhanced with an increase in the PR anthocyanin content. Additionally, the prepared CMPR smart films showed pink color in acidic pH while yellowish in basic pH solution and further exhibited strong antioxidant activity as well as antibacterial activity against the common foodborne pathogens such as S. aureus, P. aeruginosa, and E. coli. The CMPR smart film also displayed potential result for monitoring the fish fillet freshness at room temperature. The results proclaim that the prepared CMPR smart films could be utilized for quality assurance as well as shelf life extension of the marine food products.

PI3K-Akt pathway mediated antiviral mechanism in silkworm Antheraea mylitta.

Bombyx mori nucleopolyhedrosis virus (BmNPV) is a highly pathogenic virus to domestic silkworm Bombyx mori, often causing severe economic losses to silk industry. Interestingly, there are no documented reports of NPV infection in the wild silkworm Antheraea mylitta. Analysis of gene expression datasets and comparative genomic analysis of sequence datasets from B. mori and A. mylitta was undertaken to unravel the potential immune-related proteins and immune pathways involved. The B. mori silkworm races Sarupat and CSR-2 which are resistant and susceptible to BmNPV respectively were selected and challenged with virus to study BmNPV resistance related genes and their expression profile. The genes were filtered to isolate membrane proteins, their sequences were retrieved from UniProt and were compared against A. mylitta using BLASTp to search for similarity. Major proteins were putative defence proteins. Further, KEGG database was used to check for the presence of differentially regulated proteins in certain metabolic pathways. The analysis of the pathways was carried out using cytoscape software based on betweeness centrality and stress. The PI3K-Akt pathway was found to be the hub of all signals triggered during the course of NPV infection. We analyzed how the NPV infection modulates PI3K-Akt signaling by gene expression studies of the key regulator of the pathway i.e. Akt using real-time PCR in A. mylitta. A significant upregulation of Akt expression from 72 h post infection reaching its peak with a 2.30 fold change at 120 h pi clearly indicates an enhanced level of immune response in host towards the viral infection.

Biological activities of melanin pigment extracted from Bombyx mori gut-associated yeast Cryptococcus rajasthanensis KY627764.

Melanin pigment has been produced and extracted from a wide variety of living forms ranging from microorganisms to higher organisms. Owing to the therapeutic nature of the pigment, various microbial populations have been explored for its production. Hence, we isolated a melanin producing yeast from the insect Bombyx mori gut microflora and identified it as Cryptococcus rajasthanensis based on the molecular characterization. The isolated yeast produced enhanced melanin pigment when cultured in the minimal L-tyrosine broth as compared to the Saboraud medium. The pigment was extracted and characterized as melanin based on UV-Visible spectroscopy, FTIR (Fourier-transform infrared) spectroscopy and 1H NMR (Nuclear magnetic resonance). The melanin pigment was evaluated as a potent bioactive molecule with bioactivity like antimicrobial, antioxidant, anti-inflammatory, and anticancer activity that describes the therapeutic nature of the extracted melanin pigment. Distinct from the biologically active role the melanin pigment isolated from the yeast, the Cryptococcus extract also exhibited killer toxin activity against the pathogenic yeast Candida albicans.

Evaluation of multifunctional properties of gallic acid crosslinked Poly (vinyl alcohol)/Tragacanth Gum blend films for food packaging applications.

The natural polymer Tragacanth Gum is less explored as a supporting matrix, there are very less studies conducted using this polymer in literature. So the present study aims to explore the consequences of different weight percent (wt.%) of gallic acid (GA) on physicochemical properties of Poly (vinyl alcohol)/Tragacanth Gum blend films. The incorporation of GA resulted in more strengthened but less flexible films as confirmed by tensile tests. DSC studies confirmed the miscibility of composite films in the given composition range and TGA studies revealed increased thermal stability. The morphological studies revealed a homogeneous distribution of GA at lower wt.% in the blend system. X-Ray Diffraction study depicted; the added GA lost crystalline structure after incorporating it into the blend. The Water Vapor Transmission Rate (WVTR) was improved after the incorporation of GA into the blend system. Overall migration studies revealed the limited release of GA from the matrix into food simulants. Soil degradation rate increased as the wt.% of GA increased. The composite films presented strong antioxidant activity; therefore, prepared composite films could be used as an alternative to current packaging materials.

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).

In Vitro Anticancer Activity of Staphyloxanthin Pigment Extracted from Staphylococcus gallinarum KX912244, a Gut Microbe of Bombyx mori.

The present study reports the in vitro biological nature of the pigment produced by Staphylococcus gallinarum KX912244, isolated as the gut microflora bacterium of the insect Bombyx mori. The purified pigment was characterized as Staphyloxanthin based on bio-physical characterization techniques like Fourier transform infrared spectroscopy, high performance liquid chromatography, Proton nuclear magnetic resonance spectroscopy (1H NMR), Liquid chromatography-Mass spectroscopy and Gas chromatography-Mass spectroscopy. The Staphyloxanthin pigment presented considerable biological properties including in vitro antimicrobial activity against pathogens Staphylococcus aureus, Escherichia coli and Candida albicans; in vitro antioxidant activity by % DPPH free radical scavenging activity showing IC50 value of 54.22 µg/mL; DNA damage protection activity against reactive oxygen species and anticancer activity evaluated by cytotoxicity assay against 4 different cancer cell lines like the Dalton's lymphoma ascites with IC50 value 6.20 ± 0.02 µg/mL, Ehrlich ascites carcinoma having IC50 value 6.48 ± 0.15 µg/mL, Adenocarcinomic human alveolar basal epithelial cells (A549 Lung carcinoma) bearing IC50 value 7.23 ± 0.11 µg/mL and Mus mucus skin melanoma (B16F10) showing IC50 value 6.58 ± 0.38 µg/mL and less cytotoxicity towards non-cancerous human fibroblast cell lines (NIH3T3) with IC50 value of 52.24 µg/mL. The present study results suggest that Staphyloxanthin acts as a potential therapeutic agent especially due to its anticancer property.

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 ß-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.

Effective solubilization procedure for analysis of silkworm hemolymph proteins by two-dimensional gel electrophoresis.

The outstanding capability of two-dimensional gel electrophoresis in separating all types of proteins basically depends on the efficiency of sample preparation. Sample preparation is one of the most critical steps in two-dimensional gel electrophoresis. Unfortunately, due to severe solubility, resolution of protein on gel is usually hampered, and thus, analysis remains a difficult task. However, technically several problems are generally encountered during protein extraction and isoelectric focusing. In the present investigation, we emphasized on evaluation and comparison of six different protein solubilization methods intended for resolving and analyzing silkworm hemolymph proteins by two-dimensional gel electrophoresis. Our findings revealed that the buffer composition of 8 M urea, 4 % 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, 40 mM Tris base, 65 mM dithiothreitol, and 0.2 % ampholyte can effectively solubilize and yields maximum protein spots.

Rapid detection of infectious flacherie virus of the silkworm, Bombyx mori, using RT-PCR and nested PCR.

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.

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.