Digestive Physiology of the Ground Cuscus (Phalanger gymnotis), a New Guinean Phalangerid Marsupial

1997 ◽  
Vol 45 (6) ◽  
pp. 561 ◽  
Author(s):  
I. D. Hume ◽  
M. J. Runcie ◽  
J. M. Caton
Keyword(s):  
Small Intestine ◽  
Nitrogen Concentration ◽  
Distal Colon ◽  
Short Chain Fatty Acids ◽  
Proximal Colon ◽  
Brushtail Possum ◽  
Daily Production ◽  
Natural Diet ◽  
Digestible Energy ◽  
And Function

Digestive-tract morphology and function were studied in the ground cuscus (Phalanger gymnotis), reported to be the most frugivorous of eight species of New Guinean phalangerid marsupials. When offered a mixed diet of fruit and foliage, captive animals selected a diet of more than 90% fruit. Fibre digestibility was low and variable, but apparent digestibilities of both dry matter (90%) and energy (87%) were high, and intake of digestible energy was similar to that of the Australian phalangerid Trichosurus vulpecula (common brushtail possum) in captivity. The small intestine of P. gymnotis was the longest and heaviest region of the gastrointestinal tract, but the stomach contained more digesta. The total nitrogen content of digesta was low in the stomach and small intestine, but increased four-fold in the hindgut, because of microbial activity. No difference in nitrogen concentration or in the proportions of small or medium particles was found along the hindgut, but the caecum contained a smaller proportion of large particles than the distal colon. The transit time of a large particle marker was much longer than that of a solute marker, but mean retention times (MRTs) of the two markers did not differ. Both transit times and MRTs were long relative to those reported in T. vulpecula. Although fermentation rates in the caecum and proximal colon were similar to those in T. vulpecula on a foliage diet, fluid volumes were less than one-third those of T. vulpecula, and, consequently, daily production of short-chain fatty acids (SCFAs) was less than half that in T. vulpecula, and contributed only 5% of digestible energy intake (v. 15% in T. vulpecula). These results are consistent with reports that the natural diet of P. gymnotis is based largely on fruit rather than on foliage.

scholarly journals (Na+ + K+)-ATPase and plasma membrane polarity of intestinal epithelial cells: presence of a brush border antigen in the distal large intestine that is immunologically related to beta subunit.

1989 ◽  
Vol 109 (3) ◽  
pp. 1057-1069 ◽  
Author(s):  
A Marxer ◽  
B Stieger ◽  
A Quaroni ◽  
M Kashgarian ◽  
H P Hauri
Keyword(s):  
Monoclonal Antibody ◽  
Small Intestine ◽  
Epithelial Cells ◽  
Brush Border ◽  
Basolateral Membrane ◽  
Apical Cell ◽  
Distal Colon ◽  
Proximal Colon ◽  
Beta Subunit ◽  
Cell Pole

The previously produced monoclonal antibody IEC 1/48 against cultured rat intestinal crypt cells (Quaroni, A., and K. J. Isselbacher. 1981. J. Natl. Cancer Inst. 67:1353-1362) was extensively characterized and found to be directed against the beta subunit of (Na+ + K+)-ATPase as assessed by immunological and enzymatic criteria. Under nondenaturing conditions the antibody precipitated the alpha-beta enzyme complex (98,000 and 48,000 Mr). This probe, together with the monoclonal antibody C 62.4 against the alpha subunit (Kashgarian, M., D. Biemesderfer, M. Caplan, and B. Forbush. 1985. Kidney Int. 28:899-913), was used to localize (Na+ + K+)-ATPase in epithelial cells along the rat intestinal tract by immunofluorescence and immunoelectron microscopy. Both antibodies exclusively labeled the basolateral membrane of small intestine and proximal colon epithelial cells. However, in the distal colon, IEC 1/48, but not C 62.4, also labeled the brush border membrane. The cross-reacting beta-subunit-like antigen on the apical cell pole was tightly associated with isolated brush borders but was apparently devoid of (Na+ + K+)-ATPase activity. Subcellular fractionation of colonocytes in conjunction with limited proteolysis and surface radioiodination of intestinal segments suggested that the cross-reacting antigen in the brush border may be very similar to the beta subunit. The results support the notion that in the small intestine and proximal colon the enzyme subunits are exclusively targeted to the basolateral membrane while in the distal colon nonassembled beta subunit or a beta-subunit-like protein is also transported to the apical cell pole.

scholarly journals Macromolecular transport across the rabbit proximal and distal colon

Gut ◽  
1999 ◽  
Vol 44 (2) ◽  
pp. 218-225 ◽  
Author(s):  
J A Hardin ◽  
M H Kimm ◽  
M Wirasinghe ◽  
D G Gall
Keyword(s):  
Nervous System ◽  
Small Intestine ◽  
Distal Colon ◽  
Distal Segment ◽  
Proximal Colon ◽  
Colonic Epithelium ◽  
Colonic Tissue ◽  
Ussing Chambers ◽  
Macromolecular Transport ◽  
Energy Dependent

BackgroundAlthough many studies have investigated macromolecular uptake in the stomach and small intestine, little is known about macromolecular uptake in the colon.AimsTo investigate the mechanisms involved in the transport of large antigenically intact macromolecules across the proximal and distal colonic epithelium in the rabbit.MethodsThe mucosal to serosal movement of bovine serum albumin (BSA) was examined in modified Ussing chambers under short circuited conditions. The mucosal surface was exposed to varying concentrations of BSA, and after a 50 minute equilibration period, the mucosal to serosal flux of immunologically intact BSA was determined by ELISA. Total BSA flux was determined by the transport of radiolabelled 125I-BSA.ResultsIntact BSA transport in proximal and distal colonic tissue showed saturable kinetics. Intact BSA transport in the proximal and distal segment was 7% and 2% of the total 125I-BSA flux respectively. Immunologically intact BSA transport in the distal segment was significantly less than that in the proximal segment. Intact BSA transport in the proximal colon was significantly reduced following treatment with sodium fluoride, colchicine, and tetrodotoxin. Cholinergic blockade had no effect on the uptake of intact BSA.ConclusionThe findings indicate that the transport of intact macromolecules across the proximal and distal large intestine is a saturable process. Further, intact BSA transport in the proximal colon is an energy dependent process that utilises microtubules and is regulated by the enteric nervous system.

K+ transport in isolated guinea pig colonocytes: evidence for Na(+)-independent ouabain-sensitive K+ pump

1994 ◽  
Vol 266 (6) ◽  
pp. G1083-G1089 ◽  
Author(s):  
J. R. Del Castillo ◽  
M. C. Sulbaran-Carrasco ◽  
L. Burguillos
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Guinea Pig ◽  
Distal Colon ◽  
Proximal Colon ◽  
Metabolic Inhibition ◽  
Transport Mechanisms ◽  
Transport Pathway ◽  
K Transport

K+ transport mechanisms in epithelial cells isolated from guinea pig distal colon have been studied using 86Rb as a tracer. A transport pathway has been identified that is proposed to be identical to the mechanism mediating transepithelial K+ absorption. Guinea pig colonocytes take up K+ through at least three separate mechanisms: 1) a Na(+)-dependent, ouabain-sensitive influx that is consistent with the Na(+)-K+ pump, 2) a Na(+)-dependent bumetanide-sensitive influx consistent with the Na(+)-K(+)-2Cl- cotransporter, and 3) a Na(+)-independent ouabain-sensitive influx, consistent with an apical colonic K+ pump. These transport mechanisms are sensitive to metabolic inhibition by rotenone and to vanadate, a blocker of type P adenosinetriphosphatase (ATPases). SCH-28080, an inhibitor of gastric K(+)-H(+)-ATPase, was without effect. Measurements of net K+ fluxes revealed that isolated colonocytes concentrated K+ by two processes: 1) a Na(+)-dependent ouabain-sensitive mechanism, which is compatible with the Na(+)-K+ pump and 2) a Na(+)-independent ouabain-sensitive mechanism consistent with the proposed absorptive K+ pump. These concentrative mechanisms were also inhibited by rotenone and vanadate, but not by SCH-28080. The Na(+)-independent ouabain-sensitive K+ pump was present in the distal colon, but absent in the proximal colon and the small intestine of guinea pig. It is proposed that this Na(+)-independent ouabain-sensitive K+ pump mediates K+ absorption and is related to the luminal K(+)-ATPase.

scholarly journals Mucosal biopsy shows immunologic changes of the colon in patients with early MS

2017 ◽  
Vol 4 (4) ◽  
pp. e362 ◽  
Author(s):  
Adrian Mathias Moser ◽  
Walter Spindelboeck ◽  
Heimo Strohmaier ◽  
Christian Enzinger ◽  
Thomas Gattringer ◽  
...  
Keyword(s):  
Immune Cells ◽  
Colonic Mucosa ◽  
Distal Colon ◽  
Short Chain Fatty Acids ◽  
Proximal Colon ◽  
Gas Chromatography Mass Spectrometry ◽  
Proof Of Concept ◽  
Cross Sectional ◽  
Treatment Naïve ◽  
Stool Samples

Objective:To investigate immune cells of the colonic mucosa and fecal short-chain fatty acids (SCFAs) in treatment-naive patients with a clinically isolated syndrome (CIS) or early relapsing MS.Methods:In this cross-sectional proof-of-concept study, we obtained mucosal specimens during ileocolonoscopy from 15 untreated patients with CIS/MS and 10 controls. Mucosal immune cells were analyzed by FACS, and gas chromatography-mass spectrometry measurements of stool samples served to determine SCFA.Results:The number of total dendritic cells (DCs), CD103+ tolerogenic DCs, and CD4+25+127–regulatory T cells (Tregs) was significantly reduced in the distal colon of patients with CIS/MS compared with controls, whereas we found no differences in the proximal colon. The patients' fecal samples also showed a substantially lower content of SCFA and especially lower levels of butyrate and acetate.Conclusions:Our findings indicate a disturbed homeostasis of colonic DCs and Tregs in patients with MS which could be associated with colonic SCFA depletion. Although not implying causality, these findings confirm parallel abnormalities of the gut in MS and warrant further research if modulation of the colonic SCFA profile or the colonic Treg pool can serve to modify the course of MS.

scholarly journals Studies of mucus in mouse stomach, small intestine, and colon. I. Gastrointestinal mucus layers have different properties depending on location as well as over the Peyer's patches

2013 ◽  
Vol 305 (5) ◽  
pp. G341-G347 ◽  
Author(s):  
Anna Ermund ◽  
André Schütte ◽  
Malin E. V. Johansson ◽  
Jenny K. Gustafsson ◽  
Gunnar C. Hansson
Keyword(s):  
Small Intestine ◽  
Functional Organization ◽  
Distal Colon ◽  
Proximal Colon ◽  
Peyer's Patches ◽  
Peyer’S Patches ◽  
Mucus Layer ◽  
Adhesive Properties ◽  
Intestinal Mucus ◽  
Small Intestinal

Colon has been shown to have a two-layered mucus system where the inner layer is devoid of bacteria. However, a complete overview of the mouse gastrointestinal mucus system is lacking. We now characterize mucus release, thickness, growth over time, adhesive properties, and penetrability to fluorescent beads from stomach to distal colon. Colon displayed spontaneous mucus release and all regions released mucus in response to carbachol and PGE2, except the distal colon and domes of Peyer's patches. Stomach and colon had an inner mucus layer that was adherent to the epithelium. In contrast, the small intestine and Peyer's patches had a single mucus layer that was easily aspirated. The inner mucus layer of the distal colon was not penetrable to beads the size of bacteria and the inner layer of the proximal colon was only partly penetrable. In contrast, the inner mucus layer of stomach was fully penetrable, as was the small intestinal mucus. This suggests a functional organization of the intestinal mucus system, where the small intestine has loose and penetrable mucus that may allow easy penetration of nutrients, in contrast to the stomach, where the mucus provides physical protection, and the colon, where the mucus separates bacteria from the epithelium. This knowledge of the mucus system and its organization improves our understanding of the gastrointestinal tract physiology.

Intestinal distribution of human Na+/H+ exchanger isoforms NHE-1, NHE-2, and NHE-3 mRNA

1996 ◽  
Vol 271 (3) ◽  
pp. G483-G493 ◽  
Author(s):  
P. K. Dudeja ◽  
D. D. Rao ◽  
I. Syed ◽  
V. Joshi ◽  
R. Y. Dahdal ◽  
...  
Keyword(s):  
Small Intestine ◽  
Vertical Axis ◽  
Distal Colon ◽  
Proximal Colon ◽  
Hybridization Technique ◽  
Mrna Levels ◽  
Human Intestine ◽  
Relative Contribution ◽  
Specific Localization ◽  
Ribonuclease Protection

The identity of Na+/H+ exchanger (NHE) isoforms in the human small intestine and colon and their role in vectorial Na+ absorption are not known. The present studies were undertaken to examine the regional and vertical axis distribution of NHE-1, NHE-2, and NHE-3 mRNA in the human intestine. Ribonuclease protection assays were used to quantitate the levels of mRNA of these isoforms in various regions of the human intestine. In situ hybridization technique was used to localize NHE-2 and NHE-3 mRNA in the colon. The NHE-1 isoform message was present uniformly throughout the length of the human intestine. In contrast, mRNA levels for human NHE-2 and NHE-3 isoforms demonstrated significant regional differences. The NHE-3 abundance was found in decreasing order: ileum > jejunum > proximal colon = distal colon. The NHE-2 message level in the distal colon was significantly higher than in the proximal colon but was evenly distributed in the small intestine. In addition, NHE-2 mRNA was present in surface epithelial cells as well as in cells of the crypt region, suggesting the presence of NHE-2 message throughout the vertical axis of the colonic crypts. In contrast, NHE-3 mRNA was localized to surface colonocytes in the proximal colon. On the basis of this tissue-specific localization of NHE-2 and NHE-3 mRNA, it can be speculated that the relative contribution of NHE-2 and NHE-3 isoforms in Na+ absorption in the human intestine may be region specific, and these putative apical isoforms may be differentially regulated.

A review of the nutrition of Australian peramelid marsupials

2012 ◽  
Vol 34 (2) ◽  
pp. 133 ◽  
Author(s):  
Patricia J. O’Hara ◽  
Peter J. Murray ◽  
Athol V. Klieve
Keyword(s):  
Small Intestine ◽  
Gastrointestinal Tract ◽  
Water Conservation ◽  
Arid Environment ◽  
Proximal Colon ◽  
Temperate Zone ◽  
Individual Species ◽  
Free Living ◽  
Natural Diet ◽  
Nutritional Studies

European settlement has had a dramatic impact on the distribution and abundance of peramelid (bandicoot and bilby) marsupials. Predation and competition from introduced species and altered habitat have been implicated in their decline or extinction. Bandicoots and bilbies inhabit a broad range of habitats in Australia. Research on the distribution, morphology, gastrointestinal histology, lactation, metabolism and nutritional physiology of extant peramelid species has increased in the last few decades. This paper provides a review that encompasses recent nutritional-based research. Peramelid research is mostly limited to only three species – Isoodon macrourus, Perameles nasuta and Macrotis lagotis – which prevents effective comparisons between species. Peramelids are broadly classified as omnivores and possess relatively uncomplicated gastrointestinal tracts. The caecum is the region of greatest diversity among species. The relatively large caecum of Chaeropus ecaudatus supports the theory that this species may have been the only herbivorous peramelid. The caecum of M. lagotis is less pronounced than other species and is continuous with the proximal colon. M. lagotis also has a longer total colon length, which aids water conservation to ensure survival in an arid environment. Temperate-zone species such as I. macrourus, I. obesulus and P. nasuta are more similar to each other with respect to gastrointestinal morphology than either C. ecaudatus or M. lagotis. Additional research on the morphometrics of the gastrointestinal tracts of P. gunnii, P. bougainville, P. eremiana, M. leucura and I. auratus would enable further comparisons to determine whether differences are a result of geographic distribution, habitat preference or variation between genera and/or individual species. Currently, histological information of the gastrointestinal tract is limited to the small intestine of P. nasuta and I. macrourus. The histology of the small intestine of the weaned juvenile I. macrourus more closely resembles that of P. nasuta pouch young than P. nasuta adults. The younger bandicoots possessed villi whereas in the adult P. nasuta and I. macrourus villi were arranged in a zig-zag formation. The reason for the zig-zag formation of the villi and the function it may serve remains unclear. Detailed nutritional research on captive M. lagotis, I. macrourus and P. nasuta indicate that the two temperate-zone species – I. macrourus and P. nasuta – are more similar to each other than to the arid-dwelling M. lagotis. Detailed nutritional studies are required on all species, both free-living and captive. Experimental diets do not always accurately reflect a natural diet, which means that results from captive studies may not reflect the situation for free-living animals. The hindgut of peramelids is the main region for retention of digesta, and presumably where microbial digestion occurs. However, no studies have been undertaken to examine the microflora of the gastrointestinal tract of bandicoots or the bilby. As captive husbandry is an important tool in conservation management, it should also improve their successful maintenance in captivity by the provision of diets that better meet their nutritional requirements.

scholarly journals Nicotine Oral Administration Attenuates DSS-Induced Colitis Through Upregulation of Indole in the Distal Colon and Rectum in Mice

2021 ◽  
Vol 8 ◽  
Author(s):  
Akihito Nakajima ◽  
Tomoyoshi Shibuya ◽  
Takashi Sasaki ◽  
Yu Jie Lu ◽  
Dai Ishikawa ◽  
...  
Keyword(s):  
Oral Administration ◽  
Potential Role ◽  
Distal Colon ◽  
Short Chain Fatty Acids ◽  
Proximal Colon ◽  
Gut Contents ◽  
Male Mice ◽  
Histological Changes ◽  
Nicotine Administration ◽  
Colon And Rectum

Nicotine affects the gastrointestinal environment and modulates ulcerative colitis (UC). However, the associations among nicotine, gut metabolites, and UC are still largely unknown. We investigated whether orally administered nicotine affected gut metabolites and dextran sodium sulfate (DSS)-induced colitis. C57BL/6 male mice were orally administered nicotine solution in drinking water prior to inducing DSS-induced colitis. Short-chain fatty acids (SCFAs) and indole in gut contents and fecal samples were measured by GC-MS and hydroxylamine-based indole assays, respectively. Oral administration of nicotine increased indole concentration in feces, but, in contrast, SCFA values did not differ with nicotine administration. Indole levels were increased in the distal colon and rectum but not in the cecum and proximal colon. DSS-induced colitis was less severe clinically and histological changes were minimal in the rectum of orally nicotine-administered mice compared to mice drinking only water. 16S rRNA microbiome on the feces revealed an increasing in Clostridium and Porphyromonas in nicotine-administered mice. In conclusion, nicotine administration was associated with increased indole levels in the distal colon and rectum and attenuated DSS-induced colitis. Oral administration of nicotine may play a potential role in indole upregulation and prevention of UC.

scholarly journals Acute murine colitis reduces colonic 5-aminosalicylic acid metabolism by regulation of N-acetyltransferase-2

2014 ◽  
Vol 306 (11) ◽  
pp. G1002-G1010 ◽  
Author(s):  
Verónica Ramírez-Alcántara ◽  
Marshall H. Montrose
Keyword(s):  
Distal Colon ◽  
Proximal Colon ◽  
Myeloperoxidase Activity ◽  
Aminosalicylic Acid ◽  
Patient Response ◽  
Dss Colitis ◽  
Therapeutic Outcomes ◽  
Mrna Ratio ◽  
Enzyme Isoforms ◽  
And Function

Pharmacotherapy based on 5-aminosalicylic acid (5-ASA) is a preferred treatment for ulcerative colitis, but variable patient response to this therapy is observed. Inflammation can affect therapeutic outcomes by regulating the expression and activity of drug-metabolizing enzymes; its effect on 5-ASA metabolism by the colonic arylamine N-acetyltransferase (NAT) enzyme isoforms is not firmly established. We examined if inflammation affects the capacity for colonic 5-ASA metabolism and NAT enzyme expression. 5-ASA metabolism by colonic mucosal homogenates was directly measured with a novel fluorimetric rate assay. 5-ASA metabolism reported by the assay was dependent on Ac-CoA, inhibited by alternative NAT substrates (isoniazid, p-aminobenzoylglutamate), and saturable with Km (5-ASA) = 5.8 μM. A mouse model of acute dextran sulfate sodium (DSS) colitis caused pronounced inflammation in central and distal colon, and modest inflammation of proximal colon, defined by myeloperoxidase activity and histology. DSS colitis reduced capacity for 5-ASA metabolism in central and distal colon segments by 52 and 51%, respectively. Use of selective substrates of NAT isoforms to inhibit 5-ASA metabolism suggested that mNAT2 mediated 5-ASA metabolism in normal and colitis conditions. Western blot and real-time RT-PCR identified that proximal and distal mucosa had a decreased mNAT2 protein-to-mRNA ratio after DSS. In conclusion, an acute colonic inflammation impairs the expression and function of mNAT2 enzyme, thereby diminishing the capacity for 5-ASA metabolism by colonic mucosa.

scholarly journals Proximal colon–derived O-glycosylated mucus encapsulates and modulates the microbiota

Science ◽  
2020 ◽  
Vol 370 (6515) ◽  
pp. 467-472 ◽  
Author(s):  
Kirk Bergstrom ◽  
Xindi Shan ◽  
David Casero ◽  
Albert Batushansky ◽  
Venu Lagishetty ◽  
...  
Keyword(s):  
Distal Colon ◽  
Goblet Cells ◽  
Proximal Colon ◽  
Fecal Material ◽  
Mucin Production ◽  
Major Form ◽  
Minor Form ◽  
A Minor ◽  
And Function ◽  
Host Tissues

Colon mucus segregates the intestinal microbiota from host tissues, but how it organizes to function throughout the colon is unclear. In mice, we found that colon mucus consists of two distinct O-glycosylated entities of Muc2: a major form produced by the proximal colon, which encapsulates the fecal material including the microbiota, and a minor form derived from the distal colon, which adheres to the major form. The microbiota directs its own encapsulation by inducing Muc2 production from proximal colon goblet cells. In turn, O-glycans on proximal colon–derived Muc2 modulate the structure and function of the microbiota as well as transcription in the colon mucosa. Our work shows how proximal colon control of mucin production is an important element in the regulation of host-microbiota symbiosis.

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