Salusin-β is an endogenous bioactive peptide that was identified in a human full-length enriched cDNA library using bioinformatics analyses. In our previous study, we found that synthetic salusin-β exhibits antibacterial activity against only Gram-positive microorganisms such as Staphylococcus aureus NBRC 12732. Salusin-β has an ability to depolarize the cytoplasmic membrane of this bacterium, and this phenomenon may be linked to the antibacterial activity of this peptide. A cell-penetrating peptide (CPP), human immunodeficiency virus (HIV)-1 transactivator of transcription (Tat) (49-57) is a short cationic peptide that can traverse cell membranes. In this report, synthetic peptide conjugates of salusin-β and HIV-1 Tat(49-57) showed potent antibacterial activities against both Gram-positive Staphylococcus aureus NBRC 12732 and Gram-negative Escherichia coli NBRC 12734. The synthetic peptides also depolarized the cytoplasmic membrane of Escherichia coli NBRC 12734 as well as Staphylococcus aureus NBRC 12732. These results suggested that HIV-1 Tat(49-57) is a protein transduction domain or CPP that changes the interaction mode between salusin-β and the cell membrane of Escherichia coli NBRC 12734. By binding to HIV-1 Tat(49-57), salusin-β showed a broad antibacterial spectrum regardless of whether the target was a Gram-positive or Gram-negative bacterium.

We tried to measure accurately the lactoferrin concentration in human colostrum, and to study the morphology and function of human colostral cells. IgG and IgM concentrations were both very low, but IgA concentration was high in human colostrum. Lactoferrin concentration was 3,75-284 mg/dl during postparturition period. We detected the IgG-Fc and C3 receptor on the surface of colostral macrophage morphologically. Percentages of the Eand EA-rosette forming cells of colostral lymphocytes were mean 18.5% and 5.9% during postparturition period respectively. We recognized that human colostral cells have phagocytosis and killing functions against staphylococcus aureus 209P in vitro.

No abstract