(i) Although, as in vertebrates, the products of lipid hydrolysis are packaged into micelles, the amphipathic molecules of insect micelles are fatty acid-amino acid, lysophospholipid, and glycolipid complexes (442), and not bile acids (which insects lack). For example, metagenomic analyses have identified more than 700 candidate glucohydrolase genes of bacterial origin in the hindgut paunch of Nasutitermes termites, most of which have predicted capacity to degrade cellulose and xylans (462), and a remarkable 27,755 putative carbohydrate-active genes have been detected in the metagenome of the cow rumen contents, most of which are bacterial in origin, have less than 75% sequence identity with previously described genes, and many of which are likely active against cellulose (210). Nutritional development of feeding strategies in arctic ruminants: Digestive morphometry of reindeer. As in birds, a major ontogenetic change in fish is that the source of nutrients and energy necessary to continue larval development changes from the yolk reserves to the ingested food, which is mainly protein and fat in carnivores but higher in carbohydrates in omnivores and herbivores. Jongsma MA, Bolter C. The adaptation of insects to plant protease inhibitors. This issue has been explored particularly in relation to variation in the capacity of animal species with different diets to modulate their transporter activity. 1, with permission, from reference (243)]. Gut length and mass in herbivorous and carnivorous prickleback fishes (Teleostei: Stichaeidae): Ontogenetic, dietary, and phylogenetic effects. Moens PB, Kolodziejczyk S. Isozymes of amylase, alcohol dehydrogenase, malic enzyme, malate dehydrogenase, and superoxide dimutase in Chloealtis conspersa (Orthoptera), Mohan S, Ma PWK, Williams WP, Luthe DS. Adult rats exhibit diurnal variation in expression of sugar transporters in the intestine, with induction of GLUT2 (glucose transporter), GLUT5 (fructose transporter), and Pept-1 expression 3 to 4 h before the onset of peak feeding by the animal (100, 371, 402). But, there was more to the story because some populations (e.g., in sub-Saharan Africa and Saudi Arabia) that lacked the variant T-13910 nonetheless had a high prevalence of lactose tolerance. Single-nucleotide polymorphisms (SNPs) seem to explain differences among human populations in the capacity to digest lactose in milk. Human Anatomy and . In another example, when larvae of bean weavils (Zabrotes subfasciatus) were fed seeds of Phaseolus vulgaris they secreted inducible isoforms of alpha-amylases that were insensitive to the alpha-amylase inhibitor that is found in the plant, whereas their constitutively produced alpha-amylase was inhibited by SMs in the plant [reference (29); see also references (29, 403)]. As the name suggests, this system is responsible for circulating blood and nutrients throughout the body. But, for the most part, growth of the intestine matches the mammals increase in body mass or metabolic mass (body mass3/4) and the growing animal maintains a digestive and absorptive capacity that matches or slightly exceeds the demands set by increases in food intake. Caco-2 cells display a third pathway that allows the passage of molecules up to 0.13 nm diameter, suggesting an additional route in the mammalian gut intestine (448). Mountfort DO, Campbell J, Clements KD. The taxonomic composition of the microbiota in the animal GI tract varies with phylogenetic position and diet of the animal, and with location in the GI tract (116, 334, 372). They suggested that this is the reason why tubular guts predominate among complex, multicellular animals. In a phylogenetically informed allometric analysis, flying birds had shorter intestines and about 36% less nominal small intestine surface area (area of a smooth bore tube) as compared with nonflying mammals (279). The digestive adaptation of flying vertebrates: High intestinal paracellular absorption compensates for smaller guts. (2) that digesta retention time should decline, which it did. and void the remainder including cellulose [e.g., the locust Chortoicetes terminifera (92) and the grasshopper Aracris flavolineata (152)] in contrast to insect species that feed on wood and which exhibit a number of features that enable them to extract energy from cell-wall material [e.g., many termites, some cockroaches, silverfish, and firebrats (128)]. Finally, some GI microorganisms can apparently tolerate high concentrations of tannins, and tannin-tolerant or tannin-degrading bacterial species (189, 388) have been isolated from a variety of wild mammals worldwide, especially those that consume diets high in tannin content (314). But, microbes potentially provide their hosts more than those energy-rich fermentation products. The effect of dietary plant glycosides on larval midgut beta-glucosidases from Spodoptera frugiperda and Diatraea saccharalis. Ventral is the belly side. 10), and the resultant amino acids are exported via transporters on the basolateral membrane (Table 3). The cotransport of the K+ ions and amino acid into enterocytes is coupled to the ATPase-dependent extrusion of K+ ions from adjacent goblet cells. Beubler E, Juan H. Effect of ricinoleic acid and other laxatives on net water flux and prostaglandin E release by the rat colon. Nevertheless, ABCG5/G8 does not function exclusively in relation to cholesterol. Typically, the results match option (ii). Developmental regulation of a turkey intestinal peptide transporter (PepT1). to acquire those all. Sauter SN, Roffler B, Philipona C, Morel C, Rome V, Guilloteau P, Blum JW, Hammon HM. Once food passes though this region, it enters the cardiac region.In the cardiac portion of the stomach, mucus is secreted and mixed with the digested food. The discovery of efflux transporters over the past 2 to 3 decades across many animal phyla revealed another process by which passive absorption of lipophillic SMs might be limited. Discrimination between cholesterol and sitosterol for absorption in rats. Sather BT. Aphids may not, however, be typical of insects because their diet of plant phloem sap is sugar rich, and a concentration gradient from gut lumen to epithelial cell and hemocoel is maintained by the excess sugar in the gut lumen (127). Ingestion of large amounts of lactose post-weaning normally results in escape of undigested lactose to the distal GI tract where it is fermented, leading to production of gases (CO2, H2, and methane) and sometimes osmotic diarrhea. Kolkovski S. Digestive enzymes in fish larvae and juveniles - implications and applications to formulated diets. Many people don't realize that industry not only protects habitats during the workday through responsible practices, but that many of those same people are avid sportsmen and nature lovers. The site is secure. Another flavonoid, isoquercetrin, also significantly decreased glucose absorption in rats but not in robins. (392) used a phylogeny for New World bats (family Phyllostomidae) to analyze the correlation between diet and digestive enzymes in 14 species (Fig. There is now overwhelming physiological and molecular evidence for carrier-mediated uptake and also efflux across the apical membrane (Fig. 16 A), the effect was specific because aminopeptidase-N activity was unaltered (Fig. It is not known whether such genetic or phenotypic adaptive response to dietary glycosides occurs in a vertebrate species. Cancado FC, Valerio AA, Marana SR, Barbosa J. 8B). In subsequent studies, IAP-deficient (knockout) mice (190) and zebrafish (19) have been found to be hypersensitive to LPS toxicity compared with wild-type animals. 13B). Accelerated fat absorption in intestinal alkaline phosphatase knockout mice. Ontogeny of D-mannose transport and metabolism in rat small intestine. Insect fat body: Energy, metabolism, and regulation. 30 generations) of cecal valves, which slow down food passage and provide for fermenting chambers, among lizards (Podarcis melisellensis) that were introduced onto an island where they consumed eight times more vegetation than did individuals in their source population. Lecona E, Olmo N, Turnay J, Santiago-Gomez A, Lopez de Silanes I, Gorospe M, Lizarbe MA. Adaptive variation in digestive enzyme activity with diet composition is crucial to the lifestyle of many animals. In that tissue, lysozyme and other bactericidal proteins called defensins are secreted by Paneth cells located at the base of intestinal crypts (367). Murray HM, Gallant JW, Johnson SC, Douglas SE. Jia L, Betters JL, Yu L. Niemann-pick C1-like 1 (NPC1L1) protein in intestinal and hepatic cholesterol transport. The gastrointestinal (GI) tract of animals can serve multiple functions including digestion, osmoregulation, and protection (e.g., by detoxification or immune function). Narisawa S, Huang L, Iwasaki A, Hasegawa H, Alpers DH, Millan JL. Paracellular absorption is important in many birds. Most research has focused on expression response to dietary nutrients. Karasov WH. In addition, preexisting pools of transporter proteins, probably localized in the cytosol, are likely localized to the membrane; this can achieve more rapid changes in transporter activity than changes in gene expression. Dietary modulation of intestinal enzymes of the house sparrow (, Caviedes-Vidal E, Karasov WH. Identification of a variant associated with adult-type hypolactasia. All vertebrates apparently lack the capacity to degrade cellulose and related complex polysaccharides of plant cell walls. 5D), because bats in all diet groups digest protein. 14). Following uptake by diffusion and via transporters, these products are transported to the endoplasmic reticulum, where they are used to synthesize diacylglycerols (DAGs), TAGs, phospholipids, cholesterol esters, etc. We distinguish the term absorption (transport from gut lumen to body tissues by either the paracellular or transcellular route) from uptake, which refers to the transport from the gut lumen across the apical membrane of the gut epithelial cell (one step in transcellular transport). Shafizadeh TB, Halsted CH. The pig is surrounded by a layer of skin for the same reason humans' are o support and protect bones and organs. Post-feeding induction of trypsin in the midgut of. Duan CJ, Feng JX. This trait is believed to be linked to the high K+/low Na+ conditions in the gut of these insects, which eat plants with high ratios of K+/Na+. Ontogenetic development of intestinal nutrient transporters. None of them generated significant transport currents, which seems to be good direct evidence for lack of Na+-coupled transport via SGLT1. Nisbet AJ, Billingsley PF. (1) and (2), is the response to increases in energy demand as occurs in endothermic birds and mammals when temperature is reduced, or during reproduction. SCFAs are transported by the H+/monocarboxylate transporter MCT1 in several colonic cancer cell lines, including Caco-2 cells, (282) and by a Na+-dependent SCFA transporter, SLCA8, cloned from the human intestine (324), but the relevance of these transporters to SCFA transport in the colon and cecum of healthy mammals in vivo is uncertain. Notwithstanding the diversification of digestive systems caused by diversity among foods, Jumars and Penry (1987) pointed out that most guts can be analyzed as one of three categories of ideal chemical reactors, or combinations of them: batch reactors (e.g., the gastric cavity of a hydra and the blindended cecum of a rabbit), plug-flow reactors (PFRs; e.g., the tubular intestine of many invertebrates and all vertebrates), and continuous-flow stirred tank reactors (CSTRs; e.g., the rumen of a cow or the hindgut of a termite) (Fig. There is a shunt between the wall of the right and left atrium called the foramen ovale. like humans, pigs have multilobed lungs. Neal JJ. Clissold FJ, Tedder BJ, Conigrave AD, Simpson SJ. The increased fructose transport activity coincides with increased abundance of mRNA and GLUT5 protein. Tannic acid inhibition of amino acid and sugar absorption by mouse and vole intestine - tests following acute and subchronic exposure. Lavin SR, Karasov WH, Ives AR, Middleton KM, Garland TJ. However, they also concluded that if, in addition to catalytic reactions, fermentation autocatalytic reactions are important, then fermentation production rate is maximized when a portion of the gut is a CSTR. Classification and measurement of nutritionally important starch fractions. Developmental regulation of nutrient transporter and enzyme mRNA abundance in the small intestine of broilers. Both gastric and pyloric mucosa contain parietal and chief cells. Some SMs that alter digesta transit in humans and wild animals are listed in Table 4. Postnatal ontogeny of intestinal GCPII and the RFC in pig. Chediack JG, Caviedes-Vidal E, Karasov WH. For example, in response to high dietary supply of sugars, the expression of genes encoding the transporters SGLT1 (for glucose) and GLUT5 (for fructose) is increased. Another set of phenolics, catechins, which are monomeric flavanols, are reported to inhibit cholesterol absorption, perhaps by reducing micellar solubility and precipitating cholesterol (222), and they are reported to interact with lipid bilayers (336), which could lead to alterations in transport. In Drosophila, the activity of amylase in the midgut is significantly higher in larvae feeding on starch diets than sugar diets, and the 5 cis-regulatory region that regulates gene expression of the amylase genes has been identified (226). The synthesis of two trypsins, known as the late trypsins, is regulated by dietary protein content. These included an abundantly expressed gene ApSt3, a hexose uniporter with specificity for glucose and fructose in the distal midgut. This review has uncovered numerous areas for future research focused on important gaps in the comparative physiology of the GI tract. Developmental study of a-methyl-D-glucoside and L-proline uptake in the small intestine of the White Leghorn chicken. (B) Time course of absorption of [3H]L-glucose, and [14C]D-glucose and 3OMD-glucose. In at least two mammalian lineages and one avian species, the latter can be a site of lysozyme secretion. This is not necessarily the case for increased glucose-transport activity, which may occur without a coinciding large increase in SGLT1 mRNA in rats and in lamb intestine [though see reference (294)]. Peptide absorption. The efflux of unhydrolyzed peptides across the basolateral membrane is mediated by peptide transporters that have not been identified at molecular level. Intestinal lipid absorption. Skopec MM, Hagerman AE, Karasov WH. The appendix in humans is the evolutionary remains of a larger cecum in human ancestors. In: Halter F, Winton D, Wright NA, editors. Bates JM, Akerlund J, Mittge E, Guillemin K. Intestinal alkaline phosphatase detoxifies lipopolysaccharide and prevents inflammation in zebrafish in response to the gut microbiota. Gisbert E, Gimenez G, Fernandez I, Kotzamanis Y, Estevez A. Studies with colonic epithelial tissue and luminal perfusion experiments point to SCFA/HCO3 exchangers, with evidence for saturation kinetics and competitive inhibition by acetate, butyrate, and propionate, but not lactate (203, 204, 312, 378). Lavin SR, Karasov WH. Implication for the developmental regulation of the sucrase-isomaltase gene. The relationship between summated tissue respiration and metabolic rate in the mouse and dog. Cloning and characterization of an invertebrate type lysozyme from Venerupis philippinarum. Where sufficient information is available, phylogenetically informed analyses are included to provide better evidence of evolutionary trajectories and stronger inferences about the adaptive nature of certain traits. The Gut as a Model in Cell and Molecular Biology. Chediack JG, Caviedes-Vidal E, Fasulo V, Yamin LJ, Karasov WH. Physiological and Ecological Adaptations to Feeding in Vertebrates. Two have been identified in cutworms, Slctlp 1 and 2, and expression of the latter gene was analyzed in sixth instar larvae following molting from the fifth instar until pupation a week later (Fig. (B) Induced expression of Slctlp2 mRNA by starvation and refeeding in sixth instar larvae. Effect of black bean tannins on in vitro carbohydrate digestion and absorption. It is opposite the dorsal side. Fecal analyses of a range of mammals reveal diet as an important determinant of taxonomic composition (290) and genetic capacity for metabolism (334), such that the microbiota of mammals cluster according to whether the host is a carnivore, omnivore or herbivore, largely independent of the phylogenetic position of the mammal (Fig. For example, an animal derives more energy from simple sugars by gastric digestion and assimilation than by microbial fermentation; and more nitrogen from protein by gastric processing than microbial metabolism. The fate of SCFAs in the gut epithelium has been studied particularly in the rumen. Even if digestive enzymes are inhibited in vitro, the effects can, in principle, be prevented or reversed in vivo by change in pH or by surfactants (detergents) such as bile acids or other tannin-binding material in the gut such as mucus (26). Digestive physiology: A view from molecules to ecosystem. Stein ED, Diamond JM. Instead, they ascribed the difference in the inhibition by these plant SMs of glucose absorption to the rats much greater reliance on glucose transporters for intestinal glucose absorption than is the case for robins. kim kardashian workout routine and diet, motorcycle accident yesterday modesto,
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