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PubMed1988

Pepsinogen gene transcription induced in heterologous epithelial-mesenchymal recombinations of chicken endoderms and glandular stomach mesenchyme.

Proventricular (glandular stomach) mesenchyme of chicken embryos can induce endoderms of some parts of embryonic digestive tract to produce embryonic chicken pepsinogen (ECPg), a marker protein for the differentiation of embryonic proventricular epithelium. In the present study, we investigated the production of ECPg mRNA in the course of epithelial-mesenchymal interactions between endoderms of digestive tract and proventricular mesenchyme. ECPg mRNA was detected by Northern hybridization with ECPg cDNA as a probe. In normal development of the proventriculus, ECPg mRNA was first detected at day 7 of incubation, and it ceased to be produced by day 21. Embryonic esophagus, gizzard and small intestine did not contain ECPg mRNA. When 6-day esophagus, gizzard or proventricular endoderm was associated and cultured with 6-day proventricular mesenchyme, the recombinates formed proventricular-gland-like complex glands and produced ECPg mRNA in almost equal quantity. However, 6-day small intestinal or 3.5-day allantoic endoderm did not produce pepsinogen mRNA under the same conditions, though the recombinates formed complex glands. These results indicate that the proventricular mesenchyme can induce de novo transcription of ECPg gene in esophagus, proventricular and gizzard endoderms, and that ECPg gene in small intestinal and allantoic endoderms fails to react to the inducing signal.

Animals↗
PubMed1992

Tissue-specific ecdysone responses: regulation of the Drosophila genes Eip28/29 and Eip40 during larval development.

The Drosophila genes Eip28/29 and Eip40 are expressed in Kc cells and are rapidly induced by the steroid hormone ecdysone. The molecular basis for Eip28/29's regulation in those cells has been studied in some detail. To determine how this regulation relates to normal development, we have examined the expression of both genes throughout Drosophila development, with special attention to Eip28/29 and the final larval instar. Eip28/29 expression is complex; there are tissues in which it is never expressed, others in which it is continuously expressed at a low level and tissues in which its expression is regulated without obvious relationship to endocrine events. However high-level Eip28/29 expression always correlates with the presence of ecdysone and there is good evidence that Eip28/29 is directly regulated by the hormone in some tissues and at some stages. Most striking are the induction of Eip28/29 transcripts in numerous tissues at the last larval molt, their induction in the epidermis at the time of the 'late 3rd transition', their extinction in the same tissue by the premetamorphic ecdysone peak, and their induction by that peak in the lymph gland, hemocytes and proventriculus. These contrasting regulatory behaviors provide a well-defined model for studying the developmental specificity of steroid responses. Eip40 appears to be ecdysone-inducible only in the lymph gland and there only at the premetamorphic peak. The similarities been Eip28/29 and Eip40 regulation in the lymph gland and Kc cells support the idea that Kc cells are derived from a hematopoietic ancestor.

Animals↗
PubMed1995

Control of epithelial morphogenesis by cell signaling and integrin molecules in the Drosophila foregut.

Coordinated cell movements are critical for tissue and organ morphogenesis in animal development. We show that the Drosophila genes hedgehog and wingless, which encode signaling molecules, and the gene myospheroid, which encodes a beta subunit of the integrins, are required for epithelial morphogenesis during proventriculus development. In contrast, this morphogenetic process is suppressed by the decapentaplegic gene, which encodes a member of the TGF beta family of growth factors. These results identify a novel cell signaling center in the foregut that directs the formation of a multiply folded organ from a simple epithelial tube.

Animals↗
PubMed1998

cFKBP/SMAP; a novel molecule involved in the regulation of smooth muscle differentiation.

During embryogenesis, smooth muscle cells of the gut differentiate from mesenchymal cells derived from splanchnic mesoderm. We have isolated a gene involved in the differentiation of smooth muscle cells in the gut using differential display between the chicken proventriculus in which the smooth muscle layer develops poorly and the gizzard in which smooth muscles develop abundantly. The protein encoded by this gene showed highest similarity to mouse FK506 binding protein, FKBP65, and from the function of this protein it was designated chicken FKBP/smooth muscle activating protein (cFKBP/SMAP). cFKBP/SMAP was first expressed in smooth muscle precursor cells of the gut and, after smooth muscles differentiate, expression was restricted to smooth muscle cells. In organ culture of the gizzard, the differentiation of smooth muscle cells was inhibited by the addition of FK506, the inhibitor of FKBPs. Moreover, overexpression of cFKBP/SMAP in lung and gizzard mesenchymal cells induced smooth muscle differentiation. In addition, cFKBP/SMAP-induced smooth muscle differentiation was inhibited by FK506. We postulate therefore that cFKBP/SMAP plays a crucial role in smooth muscle differentiation in the gut and provides a powerful tool to study smooth muscle differentiation mechanisms, which have been poorly analyzed so far.

Amino Acid Sequence↗
PubMed2001

Specification of left-right asymmetry in the embryonic gut of Drosophila.

Most animals exhibit stable left-right asymmetries in their body. Although significant progress has been made in elucidating the mechanisms that set up these asymmetries in vertebrates, nothing is known about them in Drosophila. This is usually attributed to the fact that no reversals of stable left-right asymmetries have been observed in Drosophila, although relevant surveys have been carried out. We have focused on the asymmetry of the proventriculus in the embryonic gut of Drosophila, an aspect of left-right asymmetry that is extremely stable in wild-type flies. We show that this asymmetry can be reversed by mutations in the dicephalic and wunen genes, which also cause reversals in the antero-posterior axis of the embryo relative to its mother. This is the first observation to suggest that left-right asymmetries in Drosophila can be reversed by genetic/developmental manipulations. It also suggests that maternal signals may initiate the specification of some left-right asymmetries in the embryo.

Animals↗
PubMed2001

Haemolymph sugar levels in foraging honeybees (Apis mellifera carnica): dependence on metabolic rate and in vivo measurement of maximal rates of trehalose synthesis.

Previous investigations of haemolymph sugar levels in honeybees have reported very different results, probably because different experimental conditions affected the activity levels of the animals. The present study investigated the dependence of haemolymph sugar levels in foraging honeybees on metabolic rate and whether the haemolymph sugar level is regulated. Free-flying foraging bees were trained to collect controlled amounts of sucrose solution of different concentrations (15%, 30% or 50% sucrose w/w). Immediately after feeding, metabolic rate was measured over a given time depending on the sucrose concentration, then crop-emptying rate and haemolymph sugar levels were measured. Bees exhibiting a wide range of metabolic rates were compared to establish whether the observed differences in haemolymph sugar levels were due to limits in the supply of sugars from the crop or in the rate of trehalose synthesis in the fat bodies. Independent of the concentration of the sucrose solution supplied, haemolymph trehalose, glucose and fructose levels were constant for metabolic rates from 0 to 4.5 ml CO(2)h(-1). At higher metabolic rates, trehalose concentration decreased while that of glucose and fructose increased, with the exception of bees fed 15% sucrose solution. As the supply of sugar from the crop via the proventriculus was sufficient to support even the highest metabolic rates, the observed pattern must result from an upper limit in the capacity of the fat body to synthesise trehalose. The maximal rate of conversion of glucose to trehalose in the fat body was therefore calculated to average 92.4 microg glucosemin(-1). However, for bees fed 15% sucrose solution both the rate of conversion of glucose to trehalose and the rate of sugar transport from the crop to the ventricle were limited, together resulting in a decrease in total haemolymph sugar levels for metabolic rates higher than 5 ml CO(2)h(-1).

Animals↗
PubMed1992

Electron microscopy of the oxynticopeptic cells of the gastric glands and the intestinal glands of the caecum of the guineapig.

Histomorphology of the gastric and intestinal glands was investigated in 19 sexually mature, adult guineapigs by light and transmission electron microscopy. Gastric glands exhibited the cytological characteristics of oxynticopeptic cells capable of both hydrochloric acid (HCl) and pepsinogen secretion. In the literature, occurrence of oxynticopeptic cells in the proventriculus of the domestic fowl (Toner, 1963; Bell & Freeman, 1971) and in the gastric glands of frogs has been reported (Sedar, 1961; Patt & Patt, 1969; Forte & Forte, 1970). It has been claimed by other investigators (Herriot et al., 1938; Long, 1967) that simultaneous secretion of HCl and pepsinogen by a single, not completely differentiated 'pure' cell type, was highly effective for rapid conversion of the zymogen to active enzyme. Under the light microscope with haematoxylin and eosin stain, the protein secreting activity of gastric glands in guineapigs was masked by the HCl secreting activity, thus morphologically resembling the oxyntic cells. Therefore, different cell types, for example protein-secreting peptic cells and the acid-secreting oxyntic cells, could not be distinguished on the basis of their morphology and staining affinity. For histochemical evaluation of the sections with stains-all method, most cells in the gastric glands responded by a positive reaction to protein. Further, protein containing cells were seen in the intestinal glands of the guineapig caecum. The function of this cell type was correlated with caecotrophic food habits of this species.

Animals↗
PubMed1979

Effects of nutritional factors on metabolism of dietary cadmium at levels similar to those of man.

Several nutrients are known to affect cadmium toxicity, but little is known about the effect of dietary nutrient levels on absorption and tissue retention of cadmium at low dietary levels, similar to those of man. Feeding gradedlevels of zinc in a casein-gelatin diet to young Japanese quail with 109Cd (as the chloride) and 0.062 ppm added cadmium decreased the cadmium concentrations in the proventriculus-ventriculus, duodenum, jejunum-ileum, and the liver, but not in the kidney. Zinc also affected some zinc, iron, manganese, and copper tissue levels. Different tissue concentration patterns of cadmium and essential minerals were obtained with two purified control diets, one based on casein-gelatin and the other on soy isolate as the principal protein sources. The data show that relatively small dietary changes can markedly affect tissue levels of cadmium and that a low intake of zinc may increase the risk to dietary cadmium exposure. The complexity of the nutrient interrelationships and their effects on cadmium require further study to define mechanisms, which may be similar to those produced by low cadmium intakes in man.

Animal Nutritional Physiological Phenomena↗
PubMed1997

First record of Eustrongylides tubifex (Dioctophymatidae) from little grebe, Tachybaptus ruficollis in Japan.

A nematode species belonging to the genus Eustrongylides (Dioctophymatidae) was obtained from the proventriculus of Tachybaptus ruficollis, found in December, 1995 in Kobe City, Hyogo Prefecture, Japan. Observation under a scanning electron microscope to investigate anterior extremity with the labial papillae in two circles showed that this species is identical to E. tubifex. This is the first record of this species in Japan.

Animals↗
PubMed2005

An outbreak of highly pathogenic avian influenza subtype H5N1 in broiler breeders, Korea.

Highly pathogenic avian influenza (HPAI) was diagnosed in broiler breeders, submitted to the National Veterinary Research and Quarantine Service in South Korea. Grossly, the dead breeders had lesions consistent with HPAI, including pancreatic mottling, splenomegaly, pulmonary edema and congestion, and hemorrhages in the mucosa of the proventriculus, gizzard and small intestine, and on the serosal surface. Microscopically, there were necrotized hepatitis and pancreatitis, lymphocytic meningoencephalitis, myocarditis, and interstitial pneumonia. Influenza viral antigen was demonstrated in areas closely associated with histopathologic lesions. The AI virus was isolated from cecal tonsils, feces, trachea, and kidney of the chickens. The isolated virus was identified as the highly pathogenic H5N1, with a hemagglutinin proteolytic cleavage site deduced amino acid sequences of QREKRKKR/GLFGAGLFGAIAG. In order to determine the pathogenicity of the isolate, eight 6-week-old specific pathogen free chickens were inoculated intravenously with the virus, and all the birds died within 24 hr after inoculation. This is the first report of an outbreak of HPAI in the chickens in South Korea.

Amino Acid Sequence↗
PubMed1990

Avian adenovirus isolated from pigeons affected with inclusion body hepatitis.

Avian adenoviruses were isolated from two pigeons affected with inclusion body hepatitis (IBH) by using chicken embryo liver cell cultures. One of the isolates, designated strain S-PL1, replicated in the cell nuclei forming intranuclear inclusion bodies, showed adenovirus-like morphology by electron microscopy, and cross-reacted serologically with strain SR-48 known as serotype 2 of fowl adenovirus. The strain S-PL1 killed day-old chicks by subcutaneous inoculation, and its 50% chicken lethal dose was 10(3.8) plaque forming units per bird. Severe lesions characterized with IBH and pancreatitis, were produced in chicks inoculated with the virus. Intranuclear inclusion bodies were also recognized in the liver, pancreas, kidney, proventriculus, small intestine, and caecum. By indirect immunofluorescence test, intranuclear viral antigens were detected in the liver, pancreas and other tissues.

Adenoviridae↗
PubMed2025

Spiroplasma endosymbiont reduction of host lipid synthesis and Stomoxyn-like peptide contribute to trypanosome resistance in the tsetse fly Glossina fuscipes.

Tsetse flies (Glossina spp.) vector African trypanosomes that cause devastating diseases in humans and domestic animals. Within the Glossina genus, species in the Palpalis subgroup exhibit greater resistance to trypanosome infections compared to those in the Morsitans subgroup. Varying microbiota composition and species-specific genetic traits can significantly influence the efficiency of parasite transmission. Notably, infections with the endosymbiotic bacterium Spiroplasma have been documented in several Palpalis subgroup species, including Glossina fuscipes fuscipes (Gff). While Spiroplasma infections in Gff are known to hinder trypanosome transmission, the underlying mechanisms remain unknown. To investigate Spiroplasma-mediated factors affecting Gff vector competence, we conducted high-throughput RNA sequencing of the gut tissue along with functional assays. Our findings reveal elevated oxidative stress in the gut environment in the presence of Spiroplasma, evidenced by increased expression of nitric oxide synthase, which catalyzes the production of trypanocidal nitric oxide. Additionally, we observed impaired lipid biosynthesis leading to a reduction of this important class of nutrients essential for parasite and host physiologies. In contrast, trypanosome infections in Gff's midgut significantly upregulated various immunity-related genes, including a small peptide, Stomoxyn-like, homologous to Stomoxyn first discovered in the stable fly, Stomoxys calcitrans. We observed that the Stomoxyn-like locus is exclusive to the genomes of Palpalis subgroup tsetse species. GffStomoxyn is constitutively expressed in the cardia (proventriculus) and synthetic GffStomoxyn exhibits potent activity against Escherichia coli and bloodstream form of Trypanosoma brucei parasites, while showing no effect against insect stage procyclic forms or tsetse's commensal endosymbiont Sodalis in vitro. Reducing GffStomoxyn levels significantly increased trypanosome infection prevalence, indicating its potential trypanocidal role in vivo. Collectively, our results suggest that the enhanced resistance to trypanosomes observed in Spiroplasma-infected Gff may be due to the reduced lipid availability necessary for parasite metabolic maintenance. Furthermore, GffStomoxyn could play a crucial role in the initial immune response(s) against mammalian parasites early in the infection process in the gut and prevent gut colonization. We discuss the molecular characteristics of GffStomoxyn, its spatial and temporal expression regulation and its microbicidal activity against Trypanosome parasites. Our findings reinforce the nutritional influences of microbiota on host physiology and host-pathogen dynamics.

Animals↗
PubMed2005

A Drosophila KCNQ channel essential for early embryonic development.

The mammalian voltage-dependent KCNQ channels are responsible for distinct types of native potassium currents and are associated with several human diseases. We cloned a novel Drosophila KCNQ channel (dKCNQ) based on its sequence homology to the mammalian genes. When expressed in Chinese hamster ovary cells, dKCNQ gives rise to a slowly activating and slowly deactivating current that activates in the subthreshold voltage range. Like the M-current produced by mammalian KCNQ channels, dKCNQ current is sensitive to the KCNQ-specific blocker linopirdine and is suppressed by activation of a muscarinic receptor. dKCNQ is also similar to the mammalian channels in that it binds calmodulin (CaM), and CaM binding is necessary to produce functional currents. In situ hybridization analysis demonstrates that dKCNQ mRNA is present in brain cortical neurons, the cardia (proventriculus), and the nurse cells and oocytes of the ovary. We generated mutant flies with deletions in the genomic sequence of dKCNQ. Embryos produced by homozygous deletion females exhibit disorganized nuclei and fail to hatch, suggesting strongly that a maternal contribution of dKCNQ protein and/or mRNA is essential for early embryonic development.

Animals↗
PubMed2005

Drosophila signal peptide peptidase is an essential protease for larval development.

We identified the Drosophila melanogaster Signal peptide peptidase gene (Spp) that encodes a multipass transmembrane aspartyl protease. Drosophila SPP is homologous to the human signal peptide peptidase (SPP) and is distantly related to the presenilins. We show that, like human SPP, Drosophila SPP can proteolyze a model signal peptide and is sensitive to an SPP protease inhibitor and that it localizes to the endoplasmic reticulum. Expression of Drosophila SPP was first apparent at germ band extension, and in late embryos it was robust in the salivary glands, proventriculus, and tracheae. Flies bearing mutations in conserved residues or carrying deficiencies for the Spp gene had defective tracheae and died as larvae.

Amino Acid Sequence↗
PubMed2005

Oesophageal tonsil of the chicken.

The oesophageal tonsil of the chicken is a novel member of the mucosal-associated lymphoid tissue (MALT), which is located around the entrance of the proventriculus. It consists of 6 to 8 single units, which are surrounded by a thin fibrous capsule. Each one is organised around the bottom of the longitudinal folds of the oesophagus, and serves as a 'tonsillar crypt'. Stratified squamous epithelium is infiltrated by lymphoid cells, i.e. T cells, plasma cells, macrophages, and dendritic cells, but not B cells, to form lymphoepithelium (LE). In the LE vimentin-, MHC II- and ATPase-positive cells possibly represent Langerhans' cells, but the appearance of 74.3 positive cells in the LE is unusual, because the 74.3 monoclonal antibody (mAb) recognises chicken follicular dendritic cells in the germinal centre and medulla of the bursal follicles. The subepithelial lymphoid tissue is organised into T- and B-dependent regions, which are the interfollicular areas and the germinal centres, respectively. Existence of high-endothelial venules in the interfollicular region suggests an extensive cellular connection between the oesophageal tonsil and the other lymphoid organs. In the resting oesophagus the lumen is closed, but during swallowing a bolus the crypt opens and the lymphoepithelium can be exposed to undigested food, antigens, infectious agents and vaccines. The location of the oesophageal tonsil, cranial to the stomach, may provide this organ with a unique role as compared to the other parts of the MALT; namely, it may contribute to the replication of infectious bursal disease virus (IBDV) and/or the pathogenesis of infectious bursal disease.

Animals↗
PubMed2005

Trichurid nematodes in ring-necked pheasants from backyard flocks of the State of Rio de Janeiro, Brazil: frequency and pathology.

The present investigation is related to the frequency of infection and to the gross and microscopic lesions associated to the presence of trichurid worms in 50 ring-necked pheasants (Phasianus colchicus) from backyard flocks in the state of Rio de Janeiro, Brazil. In the investigated birds, the overall infection rate was of 74%, with the presence of Eucoleus perforans with 72% of prevalence and 21.2 of mean intensity, in the esophageal and crop mucosa and rarely in the junction of the proventriculus and esophagus, E. annulatus with 2% and 3 in the crop mucosa, Capillaria phasianina, with 12% and 4.3 in the cecum and small intestine and Baruscapillaria obsignata, for the first time referred in this host, with 2% and 1 in the small intestine. Clinical signs were absent. The gross lesions observed in the crop and esophagus of 14 (38.9%) pheasants parasitized with E. perforans were thickening, small nodules, congestion, and petechial haemorrhages in the mucosa. These birds presented a mean infection of 37.5 and a range of infection of 10-82. The microscopic lesions revealed chronic esophagitis with diffuse inflammatory process in the lamina propria characterized mostly by a mononuclear cell infiltrate and also with the presence of granulocytes. In the case of the parasitism of pheasants with C. phasianina, the gross lesions were absent; microscopic lesions were characterized by chronic typhlitis with mononuclear infiltrate. Gross and microscopic lesions were absent in the pheasants parasitized with E. annulatus and B. obsignata.

Animals↗
PubMedDate not supplied

Chronic effects of moniliformin in broiler and turkeys fed dietary treatments to market age.

Floor pen studies were conducted, with broilers from 1 to 7 wk of age and with turkeys from 1 to 14 wk of age, to evaluate the chronic effects of moniliformin (M). Fusarium fujikuroi (M-1214) culture material was added to typical corn-soybean basal diets to supply 0, 25, or 50 mg M/kg diet (broilers) or 0, 12.5, 25, 37.5, or 50 mg M/kg diet (turkeys). Compared with controls, chicks fed diets containing 50 mg M/kg consumed more feed, had lower body weight gain, were less efficient in converting feed to body weight gain, and had increased relative heart and proventriculus weights. Chicks fed the diet containing 50 mg M/kg also had significantly higher mortality and decreased mean corpuscular volumes compared with controls. Broilers fed 25 and 50 mg M/kg also had increased serum gamma glutamyltransferase activities. Feed intake, body weight gain, and feed conversion of turkeys fed dietary M were not affected. At 6 and 14 wk, turkeys fed 25, 37.5, or 50 mg M/kg diet had increased (P < 0.05) relative heart weights when compared with controls. At week 14, turkeys fed diets containing 37.5 or 50 mg M/kg also had increased (P < 0.05) relative liver weights compared with turkeys fed 0, 12.5, or 25 mg M/kg diet. Lesions, observed only in the hearts of broilers and turkeys fed 50 mg M/kg, were loss of cardiomyocyte cross striations, increased cardiomyocyte nuclear size, and an increased number of cardiomyocyte mitotic figures (turkeys only). Results indicate that > or = 37.5 mg M/kg is hepatoxic and > or = 25 mg M/kg is cardiotoxic to turkeys and 50 mg M/kg diet is toxic to broilers fed to market age.

Animals↗
PubMedDate not supplied

Internal papillomatosis with intrahepatic cholangiocarcinoma and gastrointestinal adenocarcinoma in a peach-fronted conure (Aratinga aurea).

A 17-yr-old pet female peach-fronted conure (Aratinga aurea) was presented with the chief complaints of mild lethargy and weight loss with increased appetite. Antemortem diagnostics included complete blood count, plasma biochemistry, and radiography. Abnormal findings included elevated inflammatory parameters (hyperfibrinogenemia) and a space-occupying mass in the region of the liver. Histologic examination of a liver biopsy sample indicated bile duct hyperplasia leading to a presumptive diagnosis of hepatoxicosis. The bird initially showed moderate improvement with supportive care, but its condition declined 9 days after the liver biopsy. Supportive care was attempted a second time, but the bird did not improve and euthanasia was elected. Abnormal gross necropsy findings were confined to the liver, which contained multiple tan nodules that exuded yellowish fluid on cut section. Histopathologic examination revealed multicentric bile duct hyperplasia and cholangiocarcinoma as well as segmental papillary hyperplasia and adenocarcinoma in the proventriculus, ventriculus, and throughout the intestinal tract. This is the first report of concurrent internal papillomatosis, gastrointestinal adenocarcinoma, and cholangiocarcinoma in a peach-fronted conure.

Adenocarcinoma↗