The gut of the mite Acarus siro is characterized on the ultrastructural level. It consists of the foregut (pharynx, esophagus), midgut (ventriculus, caeca, colon, intercolon, postcolonic diverticula, postcolon), and hindgut (anal atrium). The gut wall is formed by a single-layered epithelium; only regenerative cells are located basally and these have no contact with the lumen. Eight cell types form the whole gut: (i) simple epithelial cells forming fore- and hindgut; (ii) cells that probably produce the peritrophic membrane; (iii) regenerative cells occurring in the ventriculus, caeca, colon, and intercolon; (iv) spherite cells and (v) digestive cells forming the ventriculus and caeca; (vi) colonic cells and (vii) intercolonic cells; and (viii) cells forming the walls of postcolonic diverticula and postcolon. Spherite and digestive cells change in structure during secretory cycles, which are described and discussed. The cycle of spherite, colonic, and intercolonic cells is terminated by apoptosis. Ingested food is packed into a food bolus surrounded by a single homogeneous peritrophic membrane formed by addition of lamellae that subsequently fuse together. The postcolonic diverticula serve as a shelter for filamentous bacteria, which also are abundant in the intercolon.
- MeSH
- Acari anatomie a histologie ultrastruktura MeSH
- ezofágus ultrastruktura MeSH
- farynx ultrastruktura MeSH
- gastrointestinální trakt ultrastruktura MeSH
- kolon ultrastruktura MeSH
- střeva ultrastruktura MeSH
- transmisní elektronová mikroskopie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Morphological differentiation of the intestinal epithelium in the laboratory rat occurs between the 16th and 21st day of prenatal development. The pseudostratified epithelium is rebuilt into simple epithelium of the future lining. A characteristic sign of this rebuilding is formation of primitive folds, villi and intraepithelial vacuoles corresponding in submicroscopic picture with a secondary luminization. On the tips of folds and villi groups of cells released from the epithelium are observed. In these cells expression of activated caspase-3 confirms the presence of apoptosis in the process of cell death during epithelium rebuilding.
- MeSH
- apoptóza MeSH
- epitel embryologie ultrastruktura MeSH
- kolon cytologie embryologie ultrastruktura MeSH
- krysa rodu Rattus MeSH
- střevní sliznice cytologie embryologie ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The distal colon of suckling (14-day-old) and weanling (27-day-old) rats absorbs Na+ via channel-mediated, electrogenic amiloride-sensitive Na+ transport which disappears after weaning. This transport pathway is induced by aldosterone in superficial cells of colonic epithelium. The purpose of the present study was to correlate the changes in distal colon function with changes in the apical and basolateral cell membrane surface areas of superficial enterocytes. The basolateral but not apical membrane surface density (i.e. surface areas of the basolateral and apical membranes of superficial enterocytes per unit volume of superficial enterocytes) was found to increase between postnatal day 14 and 27 (i.e. during the weaning period). The plasma concentrations of aldosterone were very high during this period and electrogenic amiloride-sensitive Na+ transport and Na, K-ATPase activity were increased significantly. High dietary salt intake during the weaning period prevented the developmental increase of basolateral membrane surface density, inhibited electrogenic amiloride-sensitive Na+ transport and significantly depressed plasma aldosterone levels and Na, K-ATPase activity. Apical cell membrane surface density did not change significantly after a sodium load. Thus, high plasma concentrations of aldosterone and/or high colonic Na+ transport during weaning exert an important and selective effect on the basolateral membrane and are responsible for the developmental changes of this cell membrane surface during weaning. Concomitant changes in the morphology of superficial colonic enterocytes and in colonic Na+ transport suggest that the structure of the immature epithelium is related to its function.
- MeSH
- kolon metabolismus ultrastruktura MeSH
- krysa rodu Rattus MeSH
- potkani Wistar MeSH
- sodík metabolismus MeSH
- sodíko-draslíková ATPasa metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- sodík MeSH
- sodíko-draslíková ATPasa MeSH
The pathogenesis of enteric changes was studied in gnotobiotic piglets which, after hysterectomy had been infected orally with Campylobacter jejuni on the first day of their life. The involvement of the entire large intestine became clinically manifest by scouring on days post infection (DPI) 4 to DPI 5, and pathomorphologically, by simultaneous inflammation and severe edema of the intestinal wall. Histology and SEM revealed inflammatory edema with abundant neutrophils, microulcerations, focal propagation and activation of goblet cells, and a presence of mucin-positive material within the intestinal lumen. TEM examination revealed disconnected interdigitating folds and wide dilated intercellular spaces between enterocytes. The endothelial cells of small blood vessels in the lamina propria showed hypertrophy with increase in the thickness of their basal lamina. Ultrastructural lesions of the large intestinal microcirculation also support the hypothesis that disturbances in the vascular system are responsible for edema in the cecum and colon. Gnotobiotic piglets may be used as a suitable animal model to study colitis induced by C. jejuni.
- MeSH
- Campylobacter fetus MeSH
- cékum mikrobiologie ultrastruktura MeSH
- gnotobiologické modely * MeSH
- hysterektomie MeSH
- kampylobakterové infekce patologie patofyziologie MeSH
- kolon patologie ultrastruktura MeSH
- mikroskopie elektronová rastrovací MeSH
- modely nemocí na zvířatech MeSH
- prasata MeSH
- referenční hodnoty MeSH
- střevní sliznice mikrobiologie ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
