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.

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.

In Vitro Assessment of Probiotic Potential of Saccharomyces Cerevisiae DABRP5 Isolated from Bollo Batter, a Traditional Goan Fermented Food.

Bollo is a traditional Goan fermented food in which coarse wheat/wheat and finger millet is leavened with toddy. We here isolated 42 yeast strains from Bollo batter. Initial screening of the isolates with probiotic properties yielded four yeast isolates (DABRP1, DABRP2, DABRP5 and DABRP12). These isolates exhibited tolerance to high bile salt concentration and acidic pH and resistance to various antibiotics, which indicated their probiotic nature. All these yeast isolates were identified as Saccharomyces cerevisiae through D1D2-LSU-rDNA sequencing. These yeast isolates also showed higher percent hydrophobicity towards chloroform followed by n-hexadecane and o-xylene indicating their mucosal surface-adhesive property. To evaluate the safety of the isolates for them to be called as generally recognized as safe, the pathogenic behavior of the isolates determined through the in vitro hemolysis assay and evaluation of DNase and gelatinase activities. None of the isolates exhibited hemolysis or produced DNase or gelatinase and thus were considered potentially safe. In terms of beneficial effects, the most potent isolate S. cerevisiae DABRP5 showed antibacterial activity against the test pathogens. It also showed excellent antioxidant activity with DPPH free radical scavenging activity of 68.85 ± 0.69%, anti-inflammatory activity with 60.39 ± 0.34% inhibition of protein denaturation, and antidiabetic activity with 71.75 ± 0.45% inhibition of α-amylase activity. The isolate produced α-amylase, lipase, and ß-galactosidase. The probiotic potential of the isolate S. cerevisiae DABRP5 was similar to that of the reference strain (Saccharomyces boulardii CNCM I-745) used in this study. The results thus indicate that yeast isolates from Bollo batter have probiotic potential.

Pyridine- and Thiazole-Based Hydrazides with Promising Anti-inflammatory and Antimicrobial Activities along with Their In Silico Studies.

A new class of compounds formed by the linkage of -C(O)-NH- with pyridine and thiazole moieties was designed, synthesized, and characterized by various spectral approaches. The newly characterized compounds were evaluated for their antimicrobial as well as anti-inflammatory properties. The in vitro anti-inflammatory activity of these compounds was evaluated by denaturation of the bovine serum albumin method and showed inhibition in the range of IC50 values-46.29-100.60 µg/mL. Among all the tested compounds, compound 5l has the highest IC50 value and compound 5g has the least IC50 value. On the other hand, antimicrobial results revealed that compound 5j showed the lowest MIC values and compound 5a has the highest MIC values. Furthermore, molecular docking of the active compounds demonstrated a better docking score and interacted well with the target protein. Physicochemical parameters of the titled compounds were found suitable in the reference range only. The in silico molecular docking study revealed their COX-inhibitory action. Compound 5j emerged as a significant bioactive molecule among the synthesized analogues.