RESUMO
Antimicrobial peptides (AMPs) act directly on pathogens and maintain the anti-inflammatory effects and activation of immunocompetent cells. Therefore, the activation of the immune system in poultry via the elevation of endogenous AMPs has been attempted. In this study, we focused on the host defense mechanisms in the bursa of Fabricius (BF) of Japanese quail, cloned the cDNA of cathelicidin (CATH)-1 to -3, and analyzed their expression sites. In situ hybridization experiments revealed the mRNA expression of the CATHs in the interfollicular epithelium surrounding the lumen of the quail BF, which suggests that each CATH may exert its antimicrobial action directly in the BF. The intravenous injection of bacterial lipoteichoic acid and lipopolysaccharide endotoxins into the quail promoted the mRNA expression of CATH-1 and CATH-3 in the BF. The addition of CATH-1 or CATH-2 at the time of the antigen injection into mice resulted in antiserum with high antibody titers. Ad libitum administration of butyrate, a short-chain fatty acid, in the drinking water induced an increase in CATH-2 mRNA expression in the BF under certain conditions. These results may improve the defense mechanisms of quail by stimulating CATH expression in the BF through their diet.
RESUMO
Extracellular histones play a dual role-antimicrobial and cytotoxic-in host defense. In this study, we evaluated the antimicrobial and cytotoxic activities of histone H3 and identified the responsible molecular regions for these properties. Broth microdilution assays indicated that histone H3 exhibits growth inhibitory activity against not only Gram-negative and -positive bacteria but also fungi. Observations under scanning electron microscopy (SEM) revealed that histone H3 induced morphological abnormalities on the cell surface of a wide range of reference pathogens. MTT assays and SEM observations indicated that histone H3 has strong cytotoxic and cell lytic effects on mammalian normal, immortal, and tumor cell lines. Assays using synthetic peptides corresponding to fragments 1-34 (H3DP1), 35-68 (H3DP2), 69-102 (H3DP3), and 103-135 (H3DP4) of histone H3 molecule demonstrated that its antimicrobial activity and cytotoxicity are elicited by the H3DP2 and H3DP3 protein regions, respectively. Enzyme-linked endotoxin binding assays indicated that histones H3 and H3DP1, H3DP2, and H3DP4, but not H3DP3, exhibited high affinities toward lipopolysaccharide and lipoteichoic acid. Our findings are expected to contribute to the development of new histone H3-based peptide antibiotics that are not cytotoxic.
RESUMO
In this study, to investigate whether infants showed face-specific brain activity to a cartoon human face, we conducted a functional near-infrared spectroscopy (fNIRS) experiment and a behavioral experiment. In the fNIRS experiment, we measured the hemodynamic responses of 5- and 6-month-old infants to cartoon female and cartoon character faces using fNIRS. The results showed that the concentration of oxy-Hb increased for cartoon female faces but not for cartoon character faces. This indicates that face-specific brain activity occurred for cartoon female faces but not cartoon character faces, despite the fact that both are faces. In the behavioral experiment, we examined whether the 5- and 6-month-old infants preferred cartoon female faces to cartoon character faces in the upright and inverted conditions. The results showed a preference for cartoon female faces in the upright but not in the inverted condition. This indicates that 5- and 6-month-old infants can perceive cartoon female faces, but not cartoon character faces, as faces. The results of the two experiments indicated that face-specific brain activity occurred for cartoon female faces. This indicates that infants can perceive cartoon female faces as faces.
