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Receptors for the V4 strain of Newcastle disease virus in the digestive tract of chickens.

Enterocytes were detached from various parts of the digestive tract of chickens by treatment with DTT or with hyaluronidase. Isolated enterocytes were exposed to suspensions of the V4 strain of Newcastle disease virus (NDV). Removal of virus from the supernatant fluid was taken as evidence of binding of virus to enterocytes and residual virus was measured both by infectivity assay and by ELISA. Enterocytes from duodenum, jejunum, ileum, caecum, and rectum bound the virus; enterocytes from oesophagus, crop and proventriculus did not.

Animals↗

Chlamydia psittaci in turkeys: pathogenesis of infections in avian serovars A, B and D.

At 7 days of age, 4 groups, each of twenty specific pathogen free turkeys kept in isolation units were inoculated by aerosol with the Texas Turkey strain (avian Chlamydia psittaci serovar D), strain 92/1293 (avian Chlamydia psittaci serovar D), strain 84/55 (avian Chlamydia psittaci serovar A) or strain 89/1326 (avian Chlamydia psittaci serovar B). A fifth group of 4 specific pathogen free turkeys were sham inoculated controls. At daily intervals for 10 days and then twice weekly up to 34 days post infection, one bird in each group was killed and the target tissues and cells for replication and the sequence of events of serovar A, B and D infections was examined. In these turkeys, the primary site of replication was the respiratory tract. Chlamydial replication could be detected in the respiratory tract on day 1 post inoculation (p.i.) for group A, on day 3 p.i. for group B and on day 1 to 2 p.i. for groups D1 and D2. Subsequently, there was chlamydaemia and localisation in the digestive tract, in one or more parenchymatous organs, in the pericardium and in the conjunctivae. Specific immunoperoxidase staining revealed chamydiae in these organs in epithelial cells and in monomorphonuclear cells in all infected groups. The monomorphonuclear cells were identified as macrophages by double immunofluorescence staining. Chlamydiae were present in the same tissues for serovars A and D, but could not be demonstrated in proventriculus, duodenum, pancreas, ovaries and testes for serovar B. Furthermore, the intensity of replication was similar for all serovars. However, for serovar B in comparison with the other serovars, the bacteria appeared in most tissues 1 to 6 days later and the maximal replication in these tissues occurred 3 to 4 days later.

Aerosols↗

Receptors for the V4 strain of Newcastle disease virus in the digestive tract of chickens.

Enterocytes were detached from various parts of the digestive tract of chickens by treatment with DTT or with hyaluronidase. Isolated enterocytes were exposed to suspensions of the V4 strain of Newcastle disease virus (NDV). Removal of virus from the supernatant fluid was taken as evidence of binding of virus to enterocytes and residual virus was measured both by infectivity assay and by ELISA. Enterocytes from duodenum, jejunum, ileum, caecum, and rectum bound the virus; enterocytes from oesophagus, crop and proventriculus did not.

Animals↗

Presence and distribution of ghrelin-immunopositive cells in the chicken gastrointestinal tract.

The presence and distribution patterns of ghrelin, a gastric acylated peptide, were studied in the entire gastrointestinal tract of the chicken (Gallus domesticus) using the peroxidase-antiperoxidase immunohistochemical method, western blot analysis and a specific antibody against the C-terminal region of rat ghrelin. Ghrelin-immunopositive cells were observed in the mucosal layer of all segments examined. The largest numbers of ghrelin-positive cells were located at the base of lobuli of the proventriculus gland, along villi of the intestines and in crypts of the duodenum. Lower numbers of ghrelin-immunostained cells were located in crypts of jejunum and ileum and only few ghrelin-immunostained cells were detected at the base of crypts of the large intestine. Closed and open types of cells were observed in all segments. Western blot analysis confirmed the presence of ghrelin-like protein in the entire chicken gastrointestinal tract. The anatomical distribution patterns and the morphological characteristics of chicken ghrelin-positive cells suggest that they are endocrine cells. Furthermore, it is concluded that ghrelin shows a high degree of preservation during evolution from non-mammalian vertebrates to mammals.

Animals↗

Increased expression of unusual EP repeat-containing proteins in the midgut of the tsetse fly (Glossina) after bacterial challenge.

Proteins containing a glutamic acid-proline (EP) repeat epitope were immunologically detected in midguts from eight species of Glossina (tsetse flies). The molecular masses of the tsetse EP proteins differed among species groups. The amino acid sequence of one of these proteins, from Glossina palpalis palpalis, was determined and compared to the sequence of a homologue, the tsetse midgut EP protein of Glossina m. morsitans. The extended EP repeat domains comprised between 36% (G. m. morsitans) and 46% (G. p. palpalis) of the amino acid residues, but otherwise the two polypeptide chains shared most of their sequences and predicted functional domains. The levels of expression of tsetse EP protein in adult teneral midguts were markedly higher than in midguts from larvae. The EP protein was detected by immunoblotting in the fat body, proventriculus and midgut, the known major immune tissues of tsetse and is likely secreted as it was also detected in hemolymph. The EP protein was not produced by the bacterial symbionts of tsetse midguts as determined by genome analysis of Wigglesworthia glossinidia and immunoblot analysis of Sodalis glossinidius. Bacterial challenge of G. m. morsitans, by injection of live E. coli, induced augmented expression of the tsetse EP protein. The presence of EP proteins in a wide variety of tsetse, their constitutive expression in adult fat body and midguts and their upregulation after immunogen challenge suggest they play an important role as a component of the immune system in tsetse.

Amino Acid Motifs↗

The Drm-Bowl-Lin relief-of-repression hierarchy controls fore- and hindgut patterning and morphogenesis.

The elucidation of pathways linking patterning to morphogenesis is a problem of great interest. We show here that, in addition to their roles in patterning and morphogenesis of the hindgut, the Drosophila genes drumstick (drm) and bowl are required in the foregut for spatially localized gene expression and the morphogenetic processes that form the proventriculus. drm and bowl belong to a family of genes encoding C(2)H(2) zinc finger proteins; the other two members of this family are odd-skipped (odd) and sob. In both the fore- and hindgut, drm acts upstream of lines (lin), which encodes a putative transcriptional regulator, and relieves its repressive function. In spite of its phenotypic similarities with drm, bowl was found in both foregut and hindgut to act downstream, rather than upstream, of lin. These results support a hierarchy in which Drm relieves the repressive effect of Lin on Bowl, and Bowl then acts to promote spatially localized expression of genes (particularly the JAK/STAT pathway ligand encoded by upd) that control fore- and hindgut morphogenesis. Since the odd-family and lin are conserved in mosquito, mouse, and humans, we propose that the odd-family genes and lin may also interact to control patterning and morphogenesis in other insects and in vertebrates.

Animals↗

Expression of Fgf10 and Fgf receptors during development of the embryonic chicken stomach.

Fibroblast growth factor 10 (FGF10) is involved in numerous different aspects of embryonic development and especially in active epithelial-mesenchymal interactions during morphogenesis of many organs as a mesenchymal regulator by activating its receptors (FGFR1b and FGFR2b) expressed in the epithelial tissue. FGFR2b is also activated by FGF7 although FGF7 does not bind to FGFR1b. To provide basic data to analyze function of FGFs in the developing gut, here we cloned Fgf7 and studied expression patterns of Fgf7, Fgf10 and Fgfr1-4 during the development of chicken stomach (glandular stomach; proventriculus and muscular stomach; gizzard). Fgf10 is expressed both in the proventricular and gizzard mesenchyme while Fgf7 is expressed only in gizzard mesenchyme. Fgfr1-4 are expressed both in the epithelium and mesenchyme with a different spatial expression patterns. Furthermore, RT-PCR analysis reveals that Fgfr1b and Fgfr2b are expressed only in epithelia of both organs.

Amino Acid Sequence↗

Expression of COPI components during development of Drosophila melanogaster.

In a P{lArB} enhancer detector collection, a line was found that showed upregulated expression within centrally to posteriorly located germarial cysts. It was inserted in the gammaCOP locus on chromosome 3R. GammaCOP is a component of the COPI coatomer involved in membrane traffic. Most of the other known components of the COPI coatomer also showed higher expression in the posterior half of the germarium. Not only meiotic germline cysts but also migrating follicle cells upregulate the COPI subunits. During embryonic and larval development, the COPI subunits are expressed ubiquitously as expected for genes required for cell viability. In addition, they are strongly expressed in the salivary glands and the proventriculus. Whether tissue-specific transcriptional upregulation of COPI subunits is required for the reorganization of membranous compartments that are needed for the developmental processes that confer cyst polarity and follicle maturation will have to be addressed in a genetic study.

Amino Acid Sequence↗

Expression patterns of the chicken peroxisome proliferator-activated receptors (PPARs) during the development of the digestive organs.

Peroxisome proliferator-activated receptors (PPARs) play very important roles in various biological phenomena such as regulation of lipid metabolism, homeostasis, cell differentiation and proliferation, in a variety of organs and tissues. However, their functions in the development of the digestive organs have not been studied yet, although it has been supposed that they are involved in the tumor development and regression of digestive organs. To provide fundamental data to analyze functions of PPARs in the developing digestive organs in the chicken embryos, we performed thorough analysis of expression of PPARalpha, beta (delta) and gamma in the esophagus, proventriculus (glandular stomach), gizzard (muscular stomach), small and large intestines from early developmental stages to post hatch stages. The results showed that each PPAR is expressed in spatio-temporally regulated manner. In general, PPARbeta is widely expressed among digestive organs whereas PPARalpha and gamma showed restricted expression. In the intestine, all PPARs are expressed after hatch, indicating that they play important roles in the physiology of the adult intestine.

Animals↗

Effect of water deprivation on aquaporin 4 (AQP4) mRNA expression in chickens (Gallus domesticus).

Aquaporin (AQP) 4 is a member of the AQP gene family of water-selective transport proteins. We studied the effect of water deprivation on AQP4 gene expression in chickens. The nucleotide sequence of a chicken aquaporin 4 (AQP4) cDNA that encodes a protein of 335 amino acids showed high homology to mammalian AQP4. Using Northern blotting analysis, AQP4 mRNA in chickens was observed as a band of approximately 5.5 kb in several tissues in addition to the hypothalamus, proventriculus, kidney, and breast muscle. Quantitative analysis by real-time RT-PCR analysis showed that the mRNA expression of AQP4 in the hypothalamus significantly increased after dehydration. On the other hand, the mRNA expression of AQP4 in the kidney significantly decreased after dehydration. This suggests that AQP4 may play a pivotal role in osmoregulation in the chicken brain.

Amino Acid Sequence↗

Broad dissemination of Histomonas meleagridis determined by the detection of nucleic acid in different organs after experimental infection of turkeys and specified pathogen-free chickens using a mono-eukaryotic culture of the parasite.

Histomonas meleagridis, a flagellated protozoan parasite, is the causative agent of histomonosis (syn. histomoniasis, blackhead) in turkeys and chickens. The organs primarily affected by the parasite are the caeca and the liver. Until now, only few reports exist in which the parasite has been diagnosed in tissues other than those mentioned above. Hence, the aim of this study was to perform a systematic investigation of various organs of turkeys and specified pathogen-free chickens following an experimental infection with a mono-eukaryotic culture of Histomonas meleagridis in order to determine the dissemination of the flagellate in infected birds. Molecular methods like PCR and in situ hybridization were used for this purpose. For the first time, the DNA of the parasite could be detected in 13 different organs of infected turkeys by PCR including the proventriculus, duodenum, jejunum, caeca, pancreas, bursa of Fabricius, liver, kidney, spleen, heart, lung, thymus and the brain. Most of these findings were further confirmed by in situ hybridization. In contrast to the turkeys that all died shortly after the infection, all of the chickens survived without displaying any clinical symptoms. Even at necropsy, only mild pathological changes were observed in the caeca. Nevertheless, the parasite could also be detected in various organs of these birds, namely the caeca, bursa of Fabricius, kidney, heart and the brain.

Animals↗

In ovo DNA immunisation followed by a recombinant fowlpox boost is fully protective to challenge with virulent IBDV.

The aim of this study was to investigate the potential use of DNA vaccination delivered in ovo for protecting against challenge with infectious bursal disease virus (IBDV). Using a plasmid expressing the beta-galactosidase gene, DNA was successfully delivered to the embryo after in ovo injection and localises to the proventriculus and thymus. The coding sequence for the immunogenic IBDV protein, VP2, was cloned into pCI-neo, creating pCI-Vp2. Complete protection against IBDV was obtained by priming in ovo with pCI-Vp2, followed by boosting with the fowlpox recombinant, fpIBD1, also expressing the VP2 gene. This complete protection was not evident with either of the experimental vaccines on their own. An antibody response was not detected after the prime-boost vaccination, even after chicks had been challenged with IBDV, implying that the DNA prime delivered in ovo stimulated a protective cellular immune response.

Amniotic Fluid↗

FGF10 is required for cell proliferation and gland formation in the stomach epithelium of the chicken embryo.

The development of digestive organs in vertebrates involves active epithelial-mesenchymal interactions. In the chicken proventriculus (glandular stomach), the morphogenesis and cytodifferentiation of the epithelium are controlled by the inductive signaling factors that are secreted from the underlying mesenchyme. Previous studies have shown that Fgf10 is expressed in the developing chicken proventricular mesenchyme, whereas its receptors are present in the epithelium. In our present study, we show that FGF10 is an early mesenchymal signal that is critically associated with the developmental processes in the proventricular epithelium. Furthermore, virus-mediated Fgf10 overexpression in ovo results in a hypermorphic epithelial structure and an increase in epithelial cell number. In contrast, the overexpression of a secreted FGFR2b (sFGFR2b), an FGF10 antagonist, blocks cell proliferation and gland formation in the proventricular epithelium in ovo. This downregulation of proliferative activity was subsequently found to retard gland formation and also to delay differentiation of the epithelium. These results demonstrate that FGF10 signaling, mediated by FGFR1b and/or FGFR2b, is required for proliferation and gland formation in the epithelium in the developing chick embryo.

Animals↗

Flexible remodeling of organ size during spring migration of the garden warbler (Sylvia borin).

The energetic demands of long-distance migratory birds change drastically, depending on the stage of their life cycle. Changing demands are reflected in the up and down regulation of adipose tissue and organ mass. This paper presents new data on organ size changes during different stages of spring migration of garden warblers (Sylvia borin). Phenotypic mass changes were quantified in 13 organs of birds caught in Tanzania, Ethiopia and Egypt. We also sampled birds after a simulated stopover in Egypt. Some organs increased in mass up to about 1.5-fold during migration from Tanzania to Ethiopia, while some remained unchanged or even decreased in mass. During flight across the Sahara, nearly all organ masses including heart and flight muscles were reduced. Exceptionally large reductions (approximately 50%) were observed for liver, bile, spleen, kidney and digestive tract organs. The only exceptions were the testes, which increased 4-fold in mass. During the simulated stopover in Egypt, a significant recovery was observed for kidney, liver, heart, proventriculus, and small intestine. The testes continued to increase in mass. Flexible remodeling of organ size in the course of spring migration thus comprises significant changes for all quantified organs, with a variety of organ-specific patterns. Individual organ patterns are differentially shaped by functional aspects according to the different organ requirements in the alternation of flight and stopover phases, energetics, future demands, and protein requirements. Anticipatory mechanisms account for the size change of the testes, and we suggest the same for the kidney and the gall bladder.

Analysis of Variance↗

Distribution and regulation of chicken growth hormone secretagogue receptor isoforms.

Chicken ghrelin has recently been isolated as a hormone which stimulates growth hormone and corticosterone secretion in chicken. Ghrelin mediates these actions in mammals by binding to the growth hormone secretagogue receptor (GHS-R). In this study, we describe the partial cloning of two chicken GHS-R (cGHS-R) isoforms: cGHS-R1a and cGHS-R1c. cGHS-R1a and cGHS-R1c cDNA show, respectively, 81 and 78% homology with the corresponding parts of the human GHS-R1a cDNA. In contrast to the human GHS-R1b isoform, which is truncated after transmembrane domain 5 (TM-5), the chicken GHS-R1c isoform lacks 16 amino acids in TM-6 suggesting that this isoform is not active in ghrelin signal transduction. The cystein residues, N-linked glycosylation sites and potential phosphorylation sites, found in the human GHS-R1a, were also conserved in both chicken isoforms. RT-PCR analysis demonstrated cGHS-R1a and cGHS-R1c mRNA expression in all tissues tested, except liver and pancreas, with highest levels in the pituitary and the hypothalamus. Intermediate levels of expression were detected, in descending order, in the ovary, telencephalon, heart, adrenal gland, cerebellum, and optic lobes whereas low expression was detected in the brainstem, lung, kidney, proventriculus, duodenum, and colon. Very low expression was found in skin, stomach, and muscle. cGHS-R1c was expressed in lower amounts than cGHS-R1a in all analysed tissues. Administration of 1 microM chicken ghrelin to pituitaries in vitro resulted in a down-regulation of both cGHS-R isoforms within 15 min, whereas after 1h levels returned to control values. Growth hormone and corticosterone down-regulated cGHS-R1a and cGHS-R1c mRNA expression within 60 min of exposure, whereas growth hormone-releasing factor 1-29 (1 microM) only reduced cGHS-R1a mRNA expression after 60min. Thyrotropin-releasing hormone (1 microM) did not alter cGHS-R expression.

Amino Acid Sequence↗

Comparison of organochlorine concentrations and patterns between free-ranging zooplankton and zooplankton sampled from seabirds' stomachs.

To investigate the use of predators' stomach contents to measure the organochlorine load in free-ranging prey, the two zooplankton species Thysanoessa inermis (euphausiids) and Themisto libellula (amphipods) were collected simultaneously from the water column and from the seabird Brünnich's guillemot (Uria lomvia)'s stomach (from crop to proventriculus). The organochlorine compounds' concentrations and relative proportion of PCB-153 generally did not differ between the two sampling methods (least square mean of Sigma organochlorines=5.9 and 6.8 ng g(-1) wet weight for water column and stomach-sampled prey, respectively), indicating that the organochlorines in stomach-sampled prey were not yet affected by mechanical, chemical and bacterial degradation. Although the sample size is restricted, similar organochlorine concentrations and pattern in free-ranging and stomach-sampled prey may suggest that Brünnich's guillemots feed randomly on the zooplankton population rather than at more (or less) contaminated individuals. Alternatively or in addition, the similar concentrations and pattern suggest that the contaminant levels in Barents Sea zooplankton do not influence their behaviour to change the vulnerability to predation. In conclusion, the organochlorine concentrations and pattern in zooplankton collected from seabirds' stomach correspond with levels in free-ranging prey.

Animals↗

Characterization and cloning of a major high molecular weight house dust mite allergen (Der f 15) for dogs.

Although house dust mites (HDM(s)) are important elicitors of canine allergy, the low molecular weight molecules defined as major allergens for humans do not appear to be major allergens for dogs. Western blotting of Dermatophagoides farinae (D. farinae) extracts with sera from sensitized dogs showed that the majority of animals had IgE antibodies specific for two proteins of apparent molecular weights of 98 and 109kDa (98/109kDa). The N-terminal sequences of these two proteins were identical, suggesting they were very closely related, and sequencing of internal peptides showed the protein(s) to have homology with insect chitinases. A purified preparation of 98/109kDa proteins elicited positive intradermal skin tests (IDST(s)) in a group of well-characterized atopic dogs sensitized to D. farinae, but not in normal dogs. A rabbit polyclonal antiserum raised against the purified proteins was used to immunoscreen a D. farinae cDNA library. The mature coding region of the isolated chitinase cDNA predicts a protein of 63.2kDa; sequence analysis and glycan detection blotting suggest that the molecule is extensively O-glycosylated. Monoclonal antibodies made against the purified native protein were used to localize the chitinase in sections of whole D. farinae mites. The protein displayed an intracellular distribution in the proventriculus and intestine of the mite, suggesting that it has a digestive, rather than a moulting-related, function. The high prevalence of IgE antibodies to this antigen in canine atopic dermatitis makes it a major HDM allergen for dogs, and the protein has been formally designated Der f 15.

Amino Acid Sequence↗

Distribution of progesterone receptor in chicken: novel target organs for progesterone and estrogen action.

Expression of progesterone receptor (PR) in various organs of sexually immature chickens and after estrogen treatment was studied by immunohistochemical and Western blotting analyses. Constitutive PR expression was observed in the mesothelium and stroma of the esophagus, proventriculus, liver, spleen, pancreas, heart and lung. In the urogenital tract, PR was expressed in the mesothelial and stromal cells and smooth muscle of blood vessels. Estrogen treatment induced PR expression in the stroma and smooth muscle of the gall bladder and in the epithelium and stroma of the trachea. In the ovary of immature chickens PR was localized in the epithelium, stroma and smooth muscle and was induced in the granulosal cells by estrogen. In most tissues there was more PR-B than PR-A expression and this PR-B dominance remained after estrogen treatment. These results suggest that progesterone and estrogen may have physiological effects on many organs outside the genital tract not previously known as steroid-target tissues.

Animals↗