Transcripts of antibacterial peptides in chicken erythrocytes infected with Marek's disease virus.

BACKGROUND: Chicken erythrocytes are involved in immunity through binding of toll-like receptors (TLRs) with their ligands to activate downstream signaling and lead to cytokine production in erythrocytes. Some avian ß-defensins (AvBDs) are constitutively expressed in tissues and some others can be induced by various bacteria and viruses. However, the expression of AvBDs in erythrocytes has not yet been studied extensively. RESULTS: The transcripts of eight AvBDs (AvBD1 to AvBD7, and AvBD9) and liver-expressed antimicrobial peptide-2 (LEAP-2) were found in normal chicken erythrocytes. The expression levels of AvBD2, 4 and 7 were significantly increased (P < 0.01), whereas the levels of AvBD1, 6 and 9 were significantly decreased (P < 0.01) after Marek's disease virus (MDV) infection. The mRNA expression level of LEAP-2 was not significantly changed after MDV infection. Highest viral nucleic acid (VNA) of MDV in the feather tips among the tested time points was found at 14 days post-infection (d.p.i.). In addition, 35 MD5-related gene segments were detected in the erythrocytes at 14 d.p.i. by transcriptome sequencing. CONCLUSIONS: These results suggest that the AvBDs in chicken erythrocytes may participate in MDV-induced host immune responses.

Determination of N-NO bond dissociation energies of N-methyl-N-nitrosobenzenesulfonamides in acetonitrile and application in the mechanism analyses on NO transfer.

The heterolytic and homolytic N-NO bond dissociation energies of seven substituted N-methyl-N-nitrosobenzenesulfonamides (abbreviated as G-MNBS, G = p-OCH(3), p-CH(3), p-H, p-Cl, p-Br, 2,5-2Cl, m-NO(2)) in acetonitrile solution were evaluated for the first time by using titration calorimetry and relative thermodynamic cycles according to Hess' law. The results show that the energetic scales of the heterolytic and homolytic N-NO bond dissociation energies of G-MNBS in acetonitrile solution cover the ranges from 44.3 to 49.5 and from 33.0 to 34.9 kcal/mol for the neutral G-MNBS, respectively, which indicates that N-methyl-N-nitrosobenzenesulfonamides are much easier to release a NO radical (NO(*)) than to release a NO cation (NO(+)). The estimation of the heterolytic and homolytic (N-NO)(-)(*) bond dissociation energies of the seven G-MNBS radical anions in acetonitrile solution gives the energetic ranges of -15.8 to -12.9 and -3.1 to 1.8 kcal/mol for the (N-NO)(-)(*) bond homolysis and heterolysis, respectively, which means that G-MNBS radical anions are very unstable at room temperature and able to spontaneously or easily release a NO radical or NO anion (NO(-)), but releasing a NO radical is easier than releasing NO anion. These determined N-NO bond dissociation energies of G-MNBS and their radical anions have been successfully used in the mechanism analyses of NO transfer from G-MNBS to 3,6-dibromocarbazole and the reactions of NO with the substituted N-methyl-benzenesulfonamide nitranions (G-MBSN(-)) in acetonitrile solution.

Dissociation energies and charge distribution of the Co-NO bond for nitrosyl-alpha,beta,gamma,delta-tetraphenylporphinatocobalt(II) and nitrosyl-alpha,beta,gamma,delta-tetraphenylporphinatocobalt(III) in benzonitrile solution.

The first two series of Co-NO bond dissociation enthalpies in benzonitrile solution were determined for 12 cobalt(II) nitrosyl porphyrins and for 12 cobalt(III) nitrosyl porphyrins by titration calorimetry with suitable thermodynamic cycles. The results display that the energy scales of the heterolytic Co(III)-NO bond dissociation, the homolytic Co(III)-NO bond dissociation, and the homolytic Co(II)-NO bond dissociation are 14.7-23.2, 15.1-17.5, and 20.8-24.6 kcal/mol in benzonitrile solution, respectively, which not only indicates that the thermodynamic stability of cobalt(II) nitrosyl porphyrins is larger than that of the corresponding cobalt(III) nitrosyl porphyrins for homolysis in benzonitrile solution but also suggests that both cobalt(III) nitrosyl porphyrins and cobalt(II) nitrosyl porphyrins are excellent NO donors, and in addition, cobalt(III) nitrosyl porphyrins are also excellent NO(+) contributors. Hammett-type linear free energy analyses suggest that the nitrosyl group carries negative charges of 0.49 +/- 0.06 and 0.27 +/- 0.04 in T(G)PPCo(II)NO and in T(G)PPCo(III)NO, respectively, which indicates that nitric oxide is an electron-withdrawing group both in T(G)PPCo(II)NO and in T(G)PPCo(III)NO, behaving in a manner similar to Lewis acids rather than to Lewis bases. The energetic and structural information disclosed in the present work is believed to furnish hints to the understanding of cobalt nitrosyl porphyrins' biological functions in vivo.