Browsing by Subject "Small intestine"
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Item Open Access Egg storage duration and hatch window affect gene expression of nutrient transporters and intestine morphological parameters of early hatched broiler chicks(Cambridge University Press, 2016) Yalcin, S.; Gursel, I.; Bilgen, G.; Izzetoglu, G. T.; Horuluoglu, B. H.; Gucluer, G.In recent years, researchers have given emphasis on the differences in physiological parameters between early and late hatched chicks within a hatch window. Considering the importance of intestine development in newly hatched chicks, however, changes in gene expression of nutrient transporters in the jejunum of early hatched chicks within a hatch window have not been studied yet. This study was conducted to determine the effects of egg storage duration before incubation and hatch window on intestinal development and expression of PepT1 (H+-dependent peptide transporter) and SGLT1 (sodium-glucose co-transporter) genes in the jejunum of early hatched broiler chicks within a 30 h of hatch window. A total of 1218 eggs obtained from 38-week-old Ross 308 broiler breeder flocks were stored for 3 (ES3) or 14 days (ES14) and incubated at the same conditions. Eggs were checked between 475 and 480 h of incubation and 40 chicks from each egg storage duration were weighed; chick length and rectal temperature were measured. The chicks were sampled to evaluate morphological parameters and PepT1 and SGLT1 expression. The remaining chicks that hatched between 475 and 480 h were placed back in the incubator and the same measurements were conducted with those chicks at the end of hatch window at 510 h of incubation. Chick length, chick dry matter content, rectal temperature and weight of small intestine segments increased, whereas chick weight decreased during the hatch window. The increase in the jejunum length and villus width and area during the hatch window were higher for ES3 than ES14 chicks. PepT1 expression was higher for ES3 chicks compared with ES14. There was a 10.2 and 17.6-fold increase in PepT1 and SGLT1 expression of ES3 chicks at the end of hatch window, whereas it was only 2.3 and 3.3-fold, respectively, for ES14 chicks. These results suggested that egg storage duration affected development of early hatched chicks during 30 h of hatch window. It can be concluded that the ES14 chicks would be less efficiently adapted to absorption process for carbohydrates and protein than those from ES3 at the end of the hatch window.Item Open Access Molecular analysis of enginereed nanomaterials in biomedical and regenerative medicine applications(Bilkent University, 2019-04) Gündüz, NurayMolecular mechanisms are inspiration source for effective nanomaterial synthesis through minimalist bottom-up approaches. Mimicking functional biophysicochemical properties of biomacromolecules can give new insights for design and synthesis of nanomaterials used in biomedical and regenerative medicine applications. In this thesis, rationally-designed nanomaterials and their biomedical applications as oral ketone delivery and biomineralization and long-term potential toxicities were investigated. In the first chapter, basic concepts of nanomaterial design, synthesis, characterization, and nano-bio interface were explained. In the second chapter, a novel long-term nanoparticle accumulation model was developed to understand active regulation of nanoparticle uptake, nanoparticle accumulation behavior and the impact of long-term exposure on cellular machineries (e.g. ER stress). In the third chapter, the role of ketone body betahydroxybutryrate (βOHB) generated by a metabolic enzyme, hydroxymethylglutaryl CoA synthase 2 (HMGCS2), on intestinal stem cell maintenance and regeneration after radiation injury was investigated. Consequences of βOHB depletion in intestine were rectified by oral delivery of PLGA-encapsulated and oligomer forms of βOHB. The last chapter, acidic epitopes of enamel proteins (e.g. amelogenin) were integrated into self-assembling peptides to remineralize eroded enamel. Overall these studies show potential of natureinspired engineered nanomaterials in vast range of biomedical and regenerative medicine applications.Item Open Access The primary cilia of the gastrointestinal tract in homeostasis and disease at the single-cell level(Bilkent University, 2021-07) Esen, DenizThe gastrointestinal tract is regularly renewed by stem cells which divide and differentiate into functionally and morphologically distinct cell types. Several key pathways, such as Wnt, Hedgehog and Bmp, regulate the cell fate. However, it remains a mystery how the associated signaling molecules are relayed between cells to coordinate stemness and differentiation cues. Primary cilia are small antenna-like organelles that harbors many receptors for these pathways. Here public single-cell RNA sequencing data is re-analyzed to show that primary cilia expression is heterogeneous in the intestinal mesenchyme and liver. Presence of primary cilia is also validated using immunofluorescence in the stroma and muscle cells of the mouse colon, using known markers of the primary cilia. Acot7 is identified as a primary cilium associated marker and found to be expressed in myenteric ganglia. In mice challenged with DSS to model ulcerative colitis, primary cilia are observed more abundant as the area covered by crypt structures become reduced due to the loss of epithelium. Acot7 expressing ganglial cells were observed more frequently and displayed morphological differences. Additionally, mice fed a high-fat diet over 16 weeks had shortening of the colon crypts and an increase in the primary cilia. This work suggests that primary cilia exist in the gastrointestinal tract during homeostasis and participate in inflammation and diet-based adaptations.