L-Arginine hydrochloride/L-Lysine hydrochloride

New therapeutic agents for Candida albicans vaginitis are urgently awaiting to be developed because of the increasing antibiotic resistance of C. albicans. Antimicrobial peptides (AMPs) are one of the most promising choices for next-generation antibiotics. In this study, novel peptides were designed based on snake venom antimicrobial peptide cathelicidin-BF to promote anti-C. albicans activity and decrease side-effects. The designing strategies include substitutions of charged or hydrophobic amino acid residues for noncharged polar residues to promote antimicrobial activity and insertion of a hydrophobic residue in the hydrophilic side of the helix structure to reduce hemolysis. A designed tryptophan and lysine/arginine-rich cationic peptide 4 (ZY13) (VKRWKKWRWKWKKWV-NH2) exhibited excellent antimicrobial activity against either common strain or clinical isolates of antibiotic-resistant C. albicans with little hemolysis. Peptide 4 showed significant therapeutic effects on vaginitis in mice induced by the infection of clinical antibiotic-resistant C. albicans. The approaches herein might be useful for designing of AMPs.

The indigenous bacteria Bacillus sp. CFR1601 produced significant levels of endo-mannanase when grown on agro-wastes, namely, green gram husk and sunflower oil cake (25.6 IU/mL), used as sole carbon and nitrogen sources, respectively. Under immobilized cell system, synthetic supports (polyurethane foam, scotch brite, polyester; up to 33.2 IU/mL) were found marginally superior as compared to natural supports (cotton and silk; up to 28.2 IU/mL) for endo-mannanase production. Cooperative interactions between L-lysine HCl (0.3% w/v), Tween 60 (0.3% v/v), and sunflower oil cake (3.0% w/v) in central composite design response surface methodology ameliorated (1.61-fold) endo-mannanase titers to 48.0 IU/mL. Partially purified endo-mannanase was tested for its ability to produce oligosaccharides from guar gum. These oligosaccharides were tested in vitro for their ability to promote growth of Lactobacillus plantarum MTCC 5422 and Lactobacillus salivarius CHS 1E. Results indicated that low-molecular-weight degraded products from guar gum were (1) able to support the growth of tested strains [increased O.D600nm up to 2.3-fold and decrease in pH (<6.3) due to production of short chain fatty acid (SCFA)] when used as sole carbon source; and (2) after purification and analysis by electron spray ionization-mass spectrometry (ESI-MS) were found to be composed of mainly disaccharide and tetrasaccharide. The compatibility of endo-mannanase with various detergents together with wash performance test confirmed its potential applicability for laundry industry.