Multi-epitope DnaK peptide vaccine accords protection against lethal S. typhimurium challenge: Elicits both cell mediated immunity and long-lasting serum-neutralizing antibody titers.

Typhoid vaccine development has been impeded by inability of currently available vaccines to induce cellular immunity along with neutralizing antibodies against all serovars of S. Typhi and S. Paratyphi. Unfortunately, antibiotic treatment has shown to be an ineffective therapy due to development of resistance against multiple antibiotics. In the present study, we have explored the immunogenicity and protective efficacy of in-silico designed multi-epitope DnaK peptides as candidate vaccine molecules against Salmonella. Immunization studies in mouse typhoid model revealed three of these peptides (DP1, DP5 and DP7) are highly efficacious, stimulating both humoral and cell mediated immunity along with long lasting antibody memory response. There was significant increase in antibody titers (IgG, IgG1, IgG2a, IgA and IgM), lymphocyte proliferative responses and cytokine levels. Immunized groups showed marked reduction in organ bacterial load, fecal shedding and pronounced protection (upto 80%) as compared to unimmunized controls after challenge with S. typhimurium. Our results demonstrate the huge potential of DnaK peptide vaccine candidates (DP1, DP5 and DP7) to accord protective immunity with significant increase in survivability against Salmonella infection in mice, thus commending these molecules as promising agents to tackle typhoid.

Bioactive Fractions from the Chinese Caterpillar Mushroom, Ophiocordyceps sinensis (Ascomycetes), Elucidate Adaptogenic Role against Hypoxia Stress.

Ophiocordyceps sinensis, a high-altitude medicinal mushroom, is widely revered in traditional medicine for its antiproliferative, antihypercholesterolemic, energy enhancement, etc. properties. These properties are attributed to the presence of steroids, terpenoids, polyphenolics, glycosides, and glycoproteins in it. The current study presents characterization of three phenolic rich fractions (PRFs) separated from aqueous extract of O. sinensis using diethyl ether and ethyl acetate. These fractions possessed considerable antioxidant potential in terms of total phenolic content, total flavonoid content, ferric ion reducing power, and free radical scavenging efficiency. Chemical characterization of the PRFs was carried out using HPTLC and GC-MS. The diethyl ether and ethyl acetate fractions elucidated appreciable antibacterial activity against Salmonella typhi. The aqueous extract and residual phenolic fraction displayed protective effect on HEK 293 cell lines against hypoxia stress and also bestowed appreciative adaptogenic role against cold, hypoxia, and restraint stress in vivo, by decreasing levels of malondialdehyde and superoxide dismutase and incrementing reduced glutathione concentrations.

Antioxidant-Rich Peptide Fractions Derived from High-Altitude Chinese Caterpillar Medicinal Mushroom Ophiocordyceps sinensis (Ascomycetes) Inhibit Bacterial Pathogens.

Ophiocordyceps sinensis (=Cordyceps sinensis), a medicinal mushroom native to the Orient, has been extensively used for the past few centuries in traditional Chinese medicine because of its immunomodulatory, antiinflammatory, and nutraceutical properties. In the present study, three antioxidant and antibacterial Ophiocordyceps peptide fractions (COPs) were separated from the Indian variety of O. sinensis on a Sephadex G-25 resin. Amide bonds in the COPs were confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance. Cationic and hydrophobic amino acids, which are reported to be the major constituent amino acids of antimicrobial peptides, were identified in the COPs by matrix-assisted laser desorption/ionization-mass spectrometry and high-performance liquid chromatography. Putative secondary structures were predicted by circular dichroism to be ß-sheets and random coils. The COPs demonstrated substantial antioxidant potential by scavenging 2,2-diphenyl-l-picryl-hydrazyl-hydrate (median inhibitory concentration [IC50] values, 4.79-18.7 mg/mL) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sul-phonic acid (IC50 values, 4.51-14.05 mg/mL) free radicals and also by chelating heavy metal ions. Additionally, the peptide fractions were capable of significantly inhibiting bacterial pathogens viz. Escherichia coli and Salmonella typhi. The potential antibacterial mechanisms of action were established to be generation of reactive oxygen species and intracellular protein leakage within the bacterial cells.

Phenolic Rich Fractions from Mycelium and Fruiting Body of Ganoderma lucidum Inhibit Bacterial Pathogens Mediated by Generation of Reactive Oxygen Species and Protein Leakage and Modulate Hypoxic Stress in HEK 293 Cell Line.

Ganoderma lucidum (G. lucidum) fungus (Family Ganodermataceae) is widely used as a traditional medicine in China, Japan, and many Asian countries on account of its numerous medicinal properties such as antioxidant, anticancer, antimicrobial, energy enhancing, and immunostimulatory. This broad spectrum of therapeutic effects exhibited by G. lucidum is ascribed to its abundance in several classes of chemical constituents, namely, carbohydrates, flavonoids, minerals, phenolics, proteins, and steroids which possess substantial bioactivities. The aim of the current study was to prepare phenolic rich fractions (PRFs) from aqueous extract of the Indian variety of G. lucidum mycelium and fruiting body. These fractions were assessed for their antioxidant capacity by TPC (total phenolic content), TFC (total flavonoid content), FRAP (ferric reducing antioxidant power), and ABTS [2,2-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid] assays. Quantification of flavonoids and nucleobases present in the fractions was carried out by high-performance thin layer chromatography (HPTLC). The antibacterial activity of the fractions was evaluated against Escherichia coli, Salmonella typhi, and Staphylococcus aureus. The antibacterial mechanism of action of the PRFs was established to be generation of reactive oxygen species and leakage of proteins within bacterial cells. Additionally, the protective effect of the PRFs in counteracting hypoxia was observed in HEK 293 cell lines.