Bioconservation of iron and enhancement of antioxidant and antibacterial properties of chicken gizzard protein hydrolysate fermented by Pediococcus acidilactici ATTC 8042.

BACKGROUND: The poultry industry is one of the fastest growing sectors, and it generates considerable quantities of chicken gizzards (CG) every day. However, due to their hard texture and high microbial load, and due to cultural beliefs, they are not preferred by consumers. Chicken gizzards are a substantial source of proteins, iron, and other nutrients, which can be used effectively to produce nutraceuticals, rich in peptides (antioxidants and antibacterial), bio-iron, essential free amino acids, and fatty acids vital for human health. RESULTS: Lactic acid fermentation of CG by Pediococcus acidilactici ATTC 8042 increased the antioxidant activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH), azino-bis (3-ethylbenzothiaziline-6-sulphonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) by up to 26 times compared with unfermented CG (P < 0.05). The amount of hydrolysis and solvents (ethanol and water) used for extracting protein hydrolysates significantly affected the antioxidant properties. Moreover, fermented CG showed a negligible reduction in bio-iron (2-3%) compared with heat-processed CG (85 °C for 15 min), in which bio-iron was reduced by up to 20.3% (P < 0.05). The presence of unsaturated fatty acids such as C20:4 and C22:4 n-6 indicated a low level of lipid oxidation. CONCLUSION: Fermented CG, with its reasonably high antioxidant and antibacterial activity, together with a substantial amount of bio-iron and other nutritional components can serve as a functional food or feed additive to reduce oxidative stress and to treat iron deficiency. © 2020 Society of Chemical Industry.

Molecular characterization, mRNA gene expression, and antimicrobial activity of 2 new cathelicidin genes in goose.

Cathelicidins represent a major group of host defense peptides (HDPs) that share a highly conserved cathelin-like domain. In birds, this gene family has been identified in many species. However, no information was available in the goose until now. In this study, we present the molecular characterization of 2 goose cathelicidin genes, namely goose CATH2 and goose CATH3, for the first time. The complete cDNA of goose CATH2 and goose CATH3 were 571 bp and 573 bp in length, respectively, and the deduced amino acid sequences exhibited high similarity with other avian cathelicidins. Furthermore, evolutionary analyses indicated that all known cathelicidins form 3 distinct clusters from reptiles, while the oldest cathelicidin member, which is known as CATHB1, is very likely absent in the goose genome. Meanwhile, highly expressed goose CATH2 and goose CATH3 were also observed in primary and secondary lymphoid tissues, same as the observations in other avian species. In addition, chemically synthesized mature peptides of the 2 cathelicidins exerted optimal antimicrobial abilities to a range of gram-negative and gram-positive bacteria. The discovery and characterization of goose cathelicidins complete the knowledge for goose HDPs and might contribute to understanding the evolution of avian cathelicidins as well as for the development of antibacterial agents.

Proteome-based identification of chicken egg yolk proteins associated with antioxidant activity on the Qinghai-Tibetan Plateau.

In this study, a proteome analysis of Tibetan chicken egg yolk as well as the comparison to that of lowland chicken were performed by label-free quantitative proteomics. A total of 135 proteins were identified and abundances of 19 of these proteins were significantly different between these two groups. These differential proteins were mainly associated with oxidative stress, defense, energy metabolism and tissue development through bioinformatics analysis. To further verify the species-specific diversity of the antioxidant capacity, the antioxidative activities of egg yolk proteins were further invested in vitro and in Caco-2 cells. It was observed that both Tibetan and lowland chicken egg yolk proteins showed antioxidant activities, but the former exerted a much stronger effect. PIT54 and glutathione peroxidase 3 were considered to be antioxidant-related candidate proteins. These results provide substantial evidence for the molecular mechanisms of enhancing physical activity levels of egg yolk proteins, especially with regard to the cross-species protective mechanisms against oxidative stress.

Different incubation patterns affect selective antimicrobial properties of the egg interior: experimental evidence from eggs of precocial and altricial birds.

Avian eggs contend with omnipresent microorganisms entering the egg interior, where they affect embryo viability and hatchling phenotype. The incubation behaviour and deposition of egg white antimicrobial proteins (AMPs) vary highly across the avian altricial-precocial spectrum. Experimental evidence of how these alterations in avian reproductive strategies affect the antimicrobial properties of the precocial and altricial egg interior is lacking, however. Here, we tested the egg white antimicrobial activity in eggs of two representative model species, from each end of the avian altricial-precocial spectrum, against potentially pathogenic and beneficial probiotic microorganisms. Eggs were experimentally treated to mimic un-incubated eggs in the nest, partial incubation during the egg-laying period, the onset of full incubation and the increased deposition of two main egg white AMPs, lysozyme and ovotransferrin. We moreover assessed to what extent egg antimicrobial components, egg white pH and AMP concentrations varied as a result of different incubation patterns. Fully incubated precocial and altricial eggs decreased their antimicrobial activity against a potentially pathogenic microorganism, whereas partial incubation significantly enhanced the persistence of a beneficial probiotic microorganism in precocial eggs. These effects were most probably conditioned by temperature-dependent alterations in egg white pH and AMP concentrations. While lysozyme concentration and pH decreased in fully incubated precocial but not altricial eggs, egg white ovotransferrin increased along with the intensity of incubation in both precocial and altricial eggs. This study is the first to experimentally demonstrate that different incubation patterns may have selective antimicrobial potential mediated by species-specific effects on antimicrobial components in the egg white.

The expression of prostaglandins-related genes in erythrocytes of broiler chicken responds to thiram-induced tibial dyschondroplasia and recombinant glutathione-S-transferase A3 protein.

Tibial dyschondroplasia (TD) is a type of bone deformity found in fast-growing chickens, which induce inflammatory responses. Prostaglandins (PGs) implicate in bone formation and bone resorption, associated with inflammation in an autocrine/paracrine manner. This study used qRT-PCR and immunohistochemistry analysis to identify the expression patterns of PG-related genes in the erythrocytes of broiler chickens and explore the effects of thiram-induced TD and the recombinant glutathione-S-transferase A3 (rGSTA3) protein on the expression of PG-related genes: GSTA3, cyclooxygenase 2 (COX-2), prostaglandin D2 synthase (PTGDS), prostaglandin E synthase (PTGES), prostaglandin E2 receptor (PTGER) 3, PTGER4 and prostaglandin reductase 1 (PTGR1). Interestingly, the results showed that these seven PG-related genes expression was identified in the erythrocytes of broiler chicken, and thiram-induced TD suppressed the expression of these PG-related genes in the initial stage of TD and promoted their expression in TD recovery. These findings demonstrated that the immunoregulatory function of erythrocytes can be inhibited in the early stage of TD and promoted in the recovery stage by modulating the expression of PG-related genes. Further, the rGSTA3 protein can modulate the expression of PG-related genes in erythrocytes and participate in the recovery of TD.

Soluble expression, rapid purification, biological identification of chicken interferon-alpha using a thioredoxin fusion system in E. coli and its antiviral effects to H9N2 avian influenza virus.

In this paper, we report a soluble expression based on Escherichia coli and two-step purification of a novel thioredoxin-tagged chicken interferon-α fusion protein (Trx-rChIFN-α) by using pET32a(+) expression system. The mature ChIFN-α gene was amplified by Reverse transcriptase-polymerase chain reaction (RT-PCR) and subcloned into pET-32a (+) vector prior to transformation into Rosetta (DE3) competent cells. After IPTG induction, the recombinant fusion protein was expressed efficiently in the soluble fraction. The protein purification was performed by nickel affinity chromatography and DEAE anion exchange chromatography. The purified product has a purity of 95% with a yield of 47.3 mg/L of culture. The specific activity of the fusion protein reaches to 2.0 × 107 IU/mg as determined in the CEF/VSV titration system. After excision of the Trx tag by enterokinase, the remaining solo protein was confirmed as rChIFN-α protein by SDS-PAGE, N-terminal sequencing and mass spectrometry. The effects of this Trx-rChIFN-α fusion protein against H9N2 influenza virus infection were also evaluated in ovo. The results showed that the Trx-rChIFN-α protein could significantly reduce the hemagglutination titer of H9N2 virus, and the H9N2 viruses HA gene copy numbers. These findings will enable us to produce large amount and bio-active rChIFN-α protein for future applications.

Preferential binding to zinc oxide nanoparticle interface inhibits lysozyme fibrillation and cytotoxicity.

The aim of present investigation is to explore the effect of zinc oxide nanoparticles (ZnONP, 30 nm) interface on conformational dynamics and stability of lysozyme, at pH 7.4 and pH 9.0. Lysozyme adopts partially disordered conformation at pH 9.0, which adopts fibril morphology in presence of sodium dodecyl sulfate (SDS), compared to the conformation adopted at pH 7.4. However, the presence of ZnONP interface renders partially disordered lysozyme relatively regular and non-amyloidogenic conformation, and enhances the functional efficacy of lysozyme at pH 9.0. Additionally, the thermograms reveal a non-cooperative unfolding of the pH 9.0 lysozyme conformation, which accompanied with intermediate conformations that increased with increase in the interface concentration. The binding thermodynamics indicate that at pH 9.0, lysozyme conformation preferentially binds to ZnONP interface than SDS interface. The preferential binding is attributed for the resulting anti-fibrillation propensity of ZnONP interface. The data, altogether, suggest that the presence of ZnONP interface resulted in conformational rearrangements in the partially disordered lysozyme at pH 9.0 causing accumulation of non-amyloidogenic and functionally active intermediates, thus shielding the lysozyme from SDS induced fibrillation and cytotoxicity.

Ecto-enzymes activities in splenic lymphocytes of mice experimentally infected by Trypanosoma cruzi and treated with specific avian immunoglobulins: an attempt to improve the immune response.

The aim of this study was to evaluate the therapeutic efficacy of specific avian polyclonal antibodies (IgY) against Trypanosoma cruzi and their interaction with ecto-enzymes of the purinergic system (NTPDase and adenosine deaminase (ADA) activities) in splenic lymphocytes. For this, mice were divided into six groups: three non-infected (A, B, and C) and three infected (D, E, and F). The groups A and D were composed by negative and positive controls, respectively; while the groups B and E were treated prophylactically with IgY (50 mg/kg), and the groups C and F were treated therapeutically with IgY (50 mg/kg). Treatment with IgY reduced parasitemia on day 6 post-infection (PI) compared to the infected control group, but it was similar on day 8 PI. Moreover, infected and treated animals (the groups E and F) did not show neither amastigotes in the cardiac tissue nor cardiac lesions when compared to the positive control group (the group D). The E-NTPDase (ATP and ADP as substrate) and ADA activities in splenic lymphocytes increased significantly in the positive control group (the group D) compared to the negative control group (the group A). The therapeutic treatment of IgY (the group F) was able to prevent the increase of E-NTPDase and E-ADA activities compared to the positive control group (the group D), but this finding was not observed in animals that received the prophylactic treatment (the group E). The therapeutic treatment of IgY may be considered an interesting approach to improve the immune response of mice experimentally infected by T. cruzi.

Expression and activity analysis of ß Gallinacin-3 in Arabidopsis.

ß Gallinacin-3 (ß Gal-3) is an antimicrobial peptide with strong antibacterial activity against Escherichia coli, Staphylococcus aureus and Salmonella typhimurium. In this study, the ß Gal-3 gene was transferred into a plant genome by genetic engineering techniques. These transgenic plants can be used as feed additives to prevent poultry diseases and them might replace the antibiotics used in poultry industry. To ensure the ß Gal-3 expresses effectively in Arabidopsis seeds, the expression was driven by promoter Ppha cloned from the ß-phaseolin storage protein gene. A total of 294 transgenic lines were obtained by Agrobacterium-mediated transformation into Arabidopsis, and five transgenic lines were selected in which the expression levels of ß Gal-3 were more than 0.10% of the total soluble proteins. The transgenic lines with single locus were identified by Southern blotting. The expression of ß Gal-3 and the highest protein accumulation level (about 4.76 mg/g fresh weight with a maximum of 0.27% of total soluble proteins) was measured by Western blotting and ELISA, respectively. After ultrafiltration by centrifugation, the purity of recombinant ß Gal-3 was up to 73%. Taken together, our data showed that expression of ß Gal-3 with antimicrobial activity is possible and effective in Arabidopsis seeds.

Identification of two novel antioxidant peptides from edible bird's nest (Aerodramus fuciphagus) protein hydrolysates.

Edible bird's nest (EBN) is widely consumed as a delicacy and traditional medicine amongst the Chinese. In the present study, for the first time, the antioxidant properties of an EBN pepsin-trypsin hydrolysate of the swiftlet species Aerodramus fuciphagus and its ultrafiltration fractions were investigated. Thirteen peptides with molecular weights between 514.29 and 954.52 Da were identified in the EBN fraction with the use of mass spectrometry. Two novel pentapeptides Pro-Phe-His-Pro-Tyr and Leu-Leu-Gly-Asp-Pro, corresponding to f134-138 and f164-168 of cytochrome b of A. fuciphagus, indicated the highest ORAC values of 14.95 and 14.32 µM of TE µM-1 peptide, respectively. Both purified peptides showed resistance against simulated gastrointestinal proteases. In addition, both peptides had no in vitro cytotoxicity on human lung MRC-5 cells and prevented human liver carcinoma HepG2 cellular damage caused by hydroxyl radicals. Therefore, it is suggested that EBN protein hydrolysates are a good source of natural antioxidants and could be applied as nutraceutical compounds.

Anticancer effect and immunologic response to xenogeneic embryonic proteins in mice bearing Ehrlich solid carcinoma.

AIM: To investigate anticancer and immunologic effects of chicken embryonic proteins (CEP) in mice bearing Ehrlich solid carcinoma. MATERIALS AND METHODS: The study was carried out on male Balb/c mice bearing Ehrlich solid carcinoma. The immunizations were performed after the tumor transplantation. The immune status was assessed on days 7, 14, 21 and 28 after the tumor challenge. Cytotoxic activity (CAT) of macrophages (Mph), natural killer cells (NK), cytotoxic T-lymphocytes (CTL) and blood serum, as well as the influence of the blood serum on immune cells activity was checked in MTT-assay; Mph's cytochemical activity was tested in NBT-assay; Ehrlich antigen-specific or CEP-specific antibodies were detected in ELISA-assay; medium size circulating immune complexes (CIC) were detected in reaction of 4.5% polyethylene glycol precipitation. RESULTS: The immunization resulted in tumor growth suppression and significant 25.64% prolongation of the survival time. In both control and immunized mice with transplanted tumors antibodies specific to Ehrlich carcinoma antigens and to CEP were detected, but antibody response was more balanced in the treatment group. In the treatment group both cytochemical and CAT of Mph was moderately activated and well preserved until late stages of tumor development; CAT of NK and CTL remained in the range of the intact mice until day 28 after the tumor transplantation. The immunized mice were well protected from accumulation of CIC and suppressive activity of autologous blood serum. CONCLUSION: Collectively, our data indicate that CEP can elicit immunomodulating and immunoprotecting effects sufficient to provide tumor growth inhibition. The further elaboration of a xenogeneic anticancer vaccine based on CEP is warranted.

Development of feather keratin nanoparticles and investigation of their hemostatic efficacy.

Chicken feathers are considered as the major waste in poultry industry, which are mostly constituted of keratin proteins. Development of feather keratin for biomedical application is very attractive for chicken feather recycling. Human hair keratins have been demonstrated the significant hemostatic efficacy in the previous studies, but there are few reports of feather keratin for the hemostatic application. Here, the chicken feather keratin nanoparticle was developed for use as a hemostatic agent. Keratin was extracted from chicken feather in the present study, and a modified ultrasonic dispersion method was used to prepare keratin nanoparticles. The characterizations of feather keratin extracts and nanoparticles were investigated, including electrophoretic separation, amino acid composition, particle size, zeta potential, morphology, chemical structure and crystal form. Additionally, the hemostatic efficacy in vitro and in vivo of keratin nanoparticles were also studied. The results of hemostatic tests showed that the bleeding time and blood loss in tail amputation and liver scratch rat models can be significantly decreased after application of feather keratin nanoparticles, which demonstrated the potential application of feather keratin nanoparticles for hemostasis.

Interleukin-10 neutralizing antibody for detection of intestinal luminal levels and as a dietary additive in Eimeria challenged broiler chicks.

Interleukin-10 (IL-10) mRNA levels are increased within intestinal mucosa after Eimeria infection. IL-10 apical receptor presence on enterocytes suggests IL-10 is secreted into the intestinal lumen. Increased IL-10 has been shown to be central to the pathogenesis of numerous intracellular pathogens; we hypothesize luminal secretion of IL-10 enables Eimeria spp. infection in chickens. This study examines intestine luminal IL-10 levels and performance in broilers challenged with Eimeria when fed an anti-IL-10 antibody. Chicks were fed a diet (1 to 21 d) with control or anti-IL-10 antibody (0.34 g egg yolk antibody powder/Kg diet) with a saline or 10× dose of Advent coccidiosis vaccine on d 3. One chick per pen was euthanized on days 2, 4, 7, 10, 13, 16, and 19 post-challenge, bled, and intestines were collected for luminal fluid IL-10 concentrations. Body weight and feed intake were measured on d 21, and oocyst shedding was assessed on d 7 post-challenge. A significant Eimeria × antibody interaction on d 21 body weight (P < 0.05) showed chicks fed control antibody, but not anti-IL-10, had significant reductions in body weight when challenged with Eimeria spp. Oocyst shedding was increased with Eimeria challenge, but dietary antibody had no effect. Plasma carotenoid levels were reduced in Eimeria challenged chicks 4, 7, 10, and 16 days post-challenge compared to unchallenged chicks. Lack of an Eimeria × antibody interaction showed anti-IL-10 was not protective against Eimeria-induced decreases in plasma carotenoids. Eimeria challenge increased intestine luminal IL-10 on days 4 and 7 post-challenge in the cecum and jejunum, respectively, compared to unchallenged. Dietary anti-IL-10 decreased luminal IL-10 in the ileum on day 2 post-challenge when compared to control antibody fed chicks. No interaction between Eimeria challenge and antibody was observed on intestine luminal contents of IL-10, suggesting anti-IL-10 was ineffective at preventing increased Eimeria-induced luminal IL-10. In conclusion, Eimeria challenge increased intestinal luminal IL-10 and anti-IL-10 was effective at preventing Eimeria-induced decreased body weight, however the mechanism anti-IL-10 antibody protects body weight during Eimeria challenge remains unknown.

The potential molecular effects of bursal septpeptide II on immune induction and antitumor activity.

The bursa of Fabricius (BF) is the acknowledged central humoral immune organ in birds. Bursal septpeptide II (BSP-II) is an immunomodulatory bioactive peptide isolated from BF. To understand the effects of BSP-II on immune induction, gene expression profiles of hybridoma cells treated with BSP-II were evaluated. Pathway analysis showed that regulated genes were involved in cytokine-cytokine receptor interactions, T cell receptor signaling pathway, and pathway in cancer. It was observed that BSP-II reduced tumor cells proliferation and stimulated p53 expression. These results indicate potential mechanisms underlying the effects of the humoral immune system on immune induction, including antitumor activities. Our study has provided a novel insight into immunotherapeutic strategies for treating human tumors.

The potential molecular effects of bursal septpeptide II on immune induction and antitumor activity

The bursa of Fabricius (BF) is the acknowledged central humoral immune organ in birds. Bursal septpeptide II (BSP-II) is an immunomodulatory bioactive peptide isolated from BF. To understand the effects of BSP-II on immune induction, gene expression profiles of hybridoma cells treated with BSP-II were evaluated. Pathway analysis showed that regulated genes were involved in cytokine-cytokine receptor interactions, T cell receptor signaling pathway, and pathway in cancer. It was observed that BSP-II reduced tumor cells proliferation and stimulated p53 expression. These results indicate potential mechanisms underlying the effects of the humoral immune system on immune induction, including antitumor activities. Our study has provided a novel insight into immunotherapeutic strategies for treating human tumors.

Gonadotropin-inhibitory hormone-stimulation of food intake is mediated by hypothalamic effects in chicks.

Gonadotropin-inhibitory hormone (GnIH), a 12 amino acid peptide, is expressed in the avian brain and inhibits luteinizing hormone secretion. Additionally, exogenous injection of GnIH causes increased food intake of chicks although the central mechanism mediating this response is poorly understood. Hence, the purpose of our study was to elucidate the central mechanism of the GnIH orexigenic response using 12 day post hatch layer-type chicks as models. Firstly, via mass spectrometry we deduced the chicken GnIH amino acid sequence: SIRPSAYLPLRFamide. Following this we used chicken GnIH to demonstrate that intracerebroventricular (ICV) injection of 2.6 and 7.8 nmol causes increased food intake up to 150 min following injection with no effect on water intake. The number of c-Fos immunoreactive cells was quantified in appetite-associated hypothalamic nuclei following ICV GnIH and only the lateral hypothalamic area (LHA) had an increase of c-Fos positive neurons. From whole hypothalamus samples following ICV GnIH injection abundance of several appetite-associated mRNA was quantified which demonstrated that mRNA for neuropeptide Y (NPY) was increased while mRNA for proopiomelanocortin (POMC) was decreased. This was not the case for mRNA abundance in isolated LHA where NPY and POMC were not affected but melanin-concentrating hormone (MCH) mRNA was increased. A comprehensive behavior analysis was conducted after ICV GnIH injection which demonstrated a variety of behaviors unrelated to appetite were affected. In sum, these results implicate activation of the LHA in the GnIH orexigenic response and NPY, POMC and MCH are likely also involved.

Inhibition of antiviral innate immunity by birnavirus VP3 protein via blockage of viral double-stranded RNA binding to the host cytoplasmic RNA detector MDA5.

UNLABELLED: Chicken MDA5 (chMDA5), the sole known pattern recognition receptor for cytoplasmic viral RNA in chickens, initiates type I interferon (IFN) production. Infectious bursal disease virus (IBDV) evades host innate immunity, but the mechanism is unclear. We report here that IBDV inhibited antiviral innate immunity via the chMDA5-dependent signaling pathway. IBDV infection did not induce efficient type I interferon (IFN) production but antagonized the antiviral activity of beta interferon (IFN-ß) in DF-1 cells pretreated with IFN-α/ß. Dual-luciferase assays and inducible expression systems demonstrated that IBDV protein VP3 significantly inhibited IFN-ß expression stimulated by naked IBDV genomic double-stranded RNA (dsRNA). The VP3 protein competed strongly with chMDA5 to bind IBDV genomic dsRNA in vitro and in vivo, and VP3 from other birnaviruses also bound dsRNA. Site-directed mutagenesis confirmed that deletion of the VP3 dsRNA binding domain restored IFN-ß expression. Our data demonstrate that VP3 inhibits antiviral innate immunity by blocking binding of viral genomic dsRNA to MDA5. IMPORTANCE: MDA5, a known pattern recognition receptor and cytoplasmic viral RNA sensor, plays a critical role in host antiviral innate immunity. Many pathogens escape or inhibit the host antiviral immune response, but the mechanisms involved are unclear for most pathogens. We report here that birnaviruses inhibit host antiviral innate immunity via the MDA5-dependent signaling pathway. The antiviral innate immune system involving IFN-ß did not function effectively during birnavirus infection, and the viral protein VP3 significantly inhibited IFN-ß expression stimulated by naked viral genomic dsRNA. We also show that VP3 blocks MDA5 binding to viral genomic dsRNA in vitro and in vivo. Our data reveal that birnavirus-encoded viral protein VP3 is an inhibitor of the antiviral innate immune response and inhibits the antiviral innate immune response via the MDA5-dependent signaling pathway.

A dual mechanism involved in membrane and nucleic acid disruption of AvBD103b, a new avian defensin from the king penguin, against Salmonella enteritidis CVCC3377.

The food-borne bacterial gastrointestinal infection is a serious public health threat. Defensins are evolutionarily conserved innate immune components with broad-spectrum antibacterial activity that do not easily induce resistance. AvBD103b, an avian defensin with potent activity against Salmonella enteritidis, was isolated from the stomach contents of the king penguin (Aptenodytes patagonicus). To elucidate further the antibacterial mechanism of AvBD103b, its effect on the S. enteritidis CVCC3377 cell membrane and intracellular DNA was researched. The cell surface hydrophobicity and a N-phenyl-1-naphthylamine uptake assay demonstrated that AvBD103b treatment increased the cell surface hydrophobicity and outer membrane permeability. Atomic absorption spectrometry, ultraviolet spectrophotometry, flow cytometry, and transmission electron microscopy (TEM) indicated that AvBD103b treatment can lead to the release of the cellular contents and cell death through damage of the membrane. DNA gel retardation and circular dichroism analysis demonstrated that AvBD103b interacted with DNA and intercalated into the DNA base pairs. A cell cycle assay demonstrated that AvBD103b affected cellular functions, such as DNA synthesis. Our results confirmed that AvBD103b exerts its antibacterial activity by damaging the cell membrane and interfering with intracellular DNA, ultimately causing cell death, and suggested that AvBD103b may be a promising candidate as an alternative to antibiotics against S. enteritidis.

A new pathway mediating social effects on the endocrine system: female presence acting via norepinephrine release stimulates gonadotropin-inhibitory hormone in the paraventricular nucleus and suppresses luteinizing hormone in quail.

Rapid effects of social interactions on transient changes in hormonal levels are known in a wide variety of vertebrate taxa, ranging from fish to humans. Although these responses are mediated by the brain, neurochemical pathways that translate social signals into reproductive physiological changes are unclear. In this study, we analyzed how a female presence modifies synthesis and/or release of various neurochemicals, such as monoamines and neuropeptides, in the brain and downstream reproductive hormones in sexually active male Japanese quail. By viewing a female bird, sexually active males rapidly increased norepinephrine (NE) release in the paraventricular nucleus (PVN) of the hypothalamus, in which gonadotropin-inhibitory hormone (GnIH) neuronal cell bodies exist, increased GnIH precursor mRNA expression in the PVN, and decreased luteinizing hormone (LH) concentration in the plasma. GnIH is a hypothalamic neuropeptide that inhibits gonadotropin secretion from the pituitary. It was further shown that GnIH can rapidly suppress LH release after intravenous administration in this study. Centrally administered NE decreased plasma LH concentration in vivo. It was also shown that NE stimulated the release of GnIH from diencephalic tissue blocks in vitro. Fluorescence double-label immunohistochemistry indicated that GnIH neurons received noradrenergic innervations, and immunohistochemistry combined with in situ hybridization have further shown that GnIH neurons expressed α2A-adrenergic receptor mRNA. These results indicate that a female presence increases NE release in the PVN and stimulates GnIH release, resulting in the suppression of LH release in sexually active male quail.

Biochemical and functional characterization of transiently expressed in neural precursor (TENP) protein in emu egg white.

A protein transiently expressed in the neural precursors of developing tissues (TENP) was found to be present in emu (Dromaius novaehollandiae) egg white as one of the major proteins. Nucleotide analysis of its encoding cDNA revealed a sequence of 452 amino acids including a 19 amino acid peptide signal. Phylogenetic analysis determined that emu TENP was clustered within the bactericidal/permeability-increasing protein (BPI) superfamily together with other avian TENPs. RT-PCR analysis revealed that the emu TENP gene was highly expressed in the magnum of the oviduct, indicating that TENP is a major egg white component. Emu TENP was purified by anion exchange chromatography and ammonium sulfate fractionation. Unlike BPI, emu TENP exhibited antibacterial activity against Gram-positive bacteria, including Micrococcus luteus and Bacillus subtilis, but not against Gram-negative bacteria such as Escherichia coli and Salmonella Typhimurium. The results suggest that emu TENP is a potent novel antibacterial protein with a spectrum distinct from that of BPI.