Phosphofructokinase D from the epithelial cells of rat small intestine.
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ABSTRACT:
SUBMITTER: Khoja SM
PROVIDER: S-EPMC1152401 | biostudies-other | 1983 Nov
REPOSITORIES: biostudies-other
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Project description:1. Only a single phosphofructokinase isoenzyme is present in the mucosa of rat small intestine. 2. Mucosal phosphofructokinase was purified to yield a homogeneous preparation of specific activity 175 units/mg of protein. 3. The native enzyme is a tetramer, with monomer Mr 84 500 +/- 5000. 4. The native enzyme may be degraded by the action of endogenous proteinases to give two products with the same specific activity as the native enzyme: degradation occurs in the order native enzyme leads to proteolytic product 1 leads to proteolytic product 2. 5. Proteolytic product 1 has a greater mobility in cellulose acetate electrophoresis at pH8 and binds more strongly to DEAE-cellulose than does native enzyme; the converse is true for proteolytic product 2. 6. Proteolytic product 1 is a tetramer with a monomer Mr about 74 300; proteolytic product 2 is also a tetramer. 7. Native enzyme can only be prepared in the presence of proteinase inhibitors; partial purifications based on simple fractionation of crude mucosal extracts in the absence of proteinases inhibitors contain proteolytic product 2 as the main component and proteolytic product 1 together with little native enzyme. 8. Purified native mucosal phosphofructokinase displayed little co-operativity with respect to fructose 6-phosphate at pH 7.0 and was only weakly inhibited by ATP.
| S-EPMC1154369 | biostudies-other
Project description:1. The effect of depriving rats of food for 48 h on the specific activity of phosphofructokinase in the epithelial cells of the small intestine and on the regulatory properties of the enzyme displayed in crude (particle-free) mucosal extracts was studied. 2. The specific activity of phosphofructokinase, measured under optimal conditions at pH8, in the mucosa of fed rats showed a negative aboral gradient along the intestine, decreasing from 15.2 +/- 1.2 units (mumol/min)/g wet wt. in the proximal jejunum to 4.6 +/- 1.2 units/g wet wt. in the terminal ileum. 3. After starvation, the gradient was diminished, but not abolished; the diminution in gradient was due almost exclusively to a decrease in the specific activity of phosphofructokinase in the proximal jejunum by about 30%, there being no change in the terminal ileum. 4. In fed rats, the susceptibility of phosphofructokinase to inhibition by ATP, when assayed in crude mucosal extracts under suboptimal conditions, was independent of length along the small intestine; the ratio of the activity observed at pH 7.0 in the presence of 0.5 mM-fructose 6-phosphate and 2.5 mM-ATP to the optimal activity at pH 8, v0.5/V, was 0.36 +/- 0.05 in the proximal jejunum and 0.42 +/- 0.07 in the terminal ileum. 5. After starvation, the susceptibility of phosphofructokinase to inhibition by ATP was increased and was again found to be independent of length along the small intestine: after starvation, v0.5/V was 0.19 +/- 0.04 and 0.20 +/- 0.07 for the proximal jejunum and the terminal ileum respectively. 6. Re-feeding of previously starved rats on a high-carbohydrate diet overnight for 16 h restored both the specific activities of phosphofructokinase and its susceptibility to inhibition by ATP to normal values for fed rats. 7. The data support the idea that the specific activities and the regulatory properties of phosphofructokinase in the epithelial cells of rat small intestine are mediated by distinct humoral factors. 8. The changes in glucose utilization rate of the jejunum when rats are starved can in principle be accounted for by a combination of changes in the specific activity and in the regulatory properties of mucosal phosphofructokinase.
| S-EPMC1154198 | biostudies-other
Project description:Phosphodiesterase II activity was determined by using a synthetic substrate, the 2,4-dinitrophenyl ester of thymidine 3'-phosphate. The enzyme activity was determined in fractions obtained by differential centrifugation of homogenates of epithelial cells from the small intestinal mucosa of guinea pigs and rats. In guinea-pig preparations phosphodiesterase II occurred with highest specific activity in those fractions rich in succinate dehydrogenase and acid phosphatase. A lysosomal location for the guinea-pig enzyme was indicated by its structure-linked latency and by its association with particles that under-went a characteristic decrease in equilibrium density when Triton WR-1339 was injected into the animals. With rat preparations a much greater proportion of the phosphodiesterase II activity was found in the soluble fraction after ultracentrifugation. The rat enzyme exhibited a lower degree of latency and administration of Triton WR-1339 had no effect. The rat enzyme further differed from that of the guinea pig in other respects; it was more labile at 60 degrees C, it exhibited a lower pH optimum and it had a higher molecular weight as determined by gel-filtration chromatography.
| S-EPMC1168318 | biostudies-other
Project description:Human noroviruses are a major cause of diarrheal illness, but pathogenesis is poorly understood. Here, we investigate the cellular tropism of norovirus in specimens from four immunocompromised patients. Abundant norovirus antigen and RNA are detected throughout the small intestinal tract in jejunal and ileal tissue from one pediatric intestinal transplant recipient with severe gastroenteritis. Negative-sense viral RNA, a marker of active viral replication, is found predominantly in intestinal epithelial cells, with chromogranin A-positive enteroendocrine cells (EECs) identified as a permissive cell type in this patient. These findings are consistent with the detection of norovirus-positive EECs in the other three immunocompromised patients. Investigation of the signaling pathways induced in EECs that mediate communication between the gut and brain may clarify mechanisms of pathogenesis and lead to the development of in vitro model systems in which to evaluate norovirus vaccines and treatment.
| S-EPMC7265440 | biostudies-literature
Project description:The functional roles of transient receptor potential (TRP) channels in the gastrointestinal tract have garnered considerable attention in recent years. We previously reported that daikenchuto (TU-100), a traditional Japanese herbal medicine, increased intestinal blood flow (IBF) via adrenomedullin (ADM) release from intestinal epithelial (IE) cells (Kono T et al. J Crohns Colitis 4: 161-170, 2010). TU-100 contains multiple TRP activators. In the present study, therefore, we examined the involvement of TRP channels in the ADM-mediated vasodilatatory effect of TU-100. Rats were treated intraduodenally with the TRP vanilloid type 1 (TRPV1) agonist capsaicin (CAP), the TRP ankyrin 1 (TRPA1) agonist allyl-isothiocyanate (AITC), or TU-100, and jejunum IBF was evaluated using laser-Doppler blood flowmetry. All three compounds resulted in vasodilatation, and the vasodilatory effect of TU-100 was abolished by a TRPA1 antagonist but not by a TRPV1 antagonist. Vasodilatation induced by AITC and TU-100 was abrogated by anti-ADM antibody treatment. RT-PCR and flow cytometry revealed that an IEC-6 cell line originated from the small intestine and purified IE cells expressed ADM and TRPA1 but not TRPV1. AITC increased ADM release in IEC cells remarkably, while CAP had no effect. TU-100 and its ingredient 6-shogaol (6SG) increased ADM release dose-dependently, and the effects were abrogated by a TRPA1 antagonist. 6SG showed similar TRPA1-dependent vasodilatation in vivo. These results indicate that TRPA1 in IE cells may play an important role in controlling bowel microcirculation via ADM release. Epithelial TRPA1 appears to be a promising target for the development of novel strategies for the treatment of various gastrointestinal disorders.
| S-EPMC3566615 | biostudies-literature
Project description:In common with other phosphofructokinase isoenzymes, phosphofructokinase in the epithelial cells of rat small-intestinal mucosa is activated by fructose 2,6-bisphosphate. However, fructose 2,6-bisphosphate was found not to be present in mucosa as judged by three criteria: (1) chromatography on Sephadex G-25 of crude mucosal extracts from fed rats did not result in a decrease, or indeed any change, in the activity of phosphofructokinase under suboptimal conditions at pH7; (2) ultrafiltrates of mucosal extracts did not possess any acid-labile activating activity when tested against chromatographed liver phosphofructokinase; (3) phosphofructokinase-2 activity was not detectable in mucosal extracts. Furthermore, the perfusion in vitro of isolated loops of jejunum or the incubation of mucosal scrapings from either fed rats or rats starved for 48 h showed that the activity of mucosal phosphofructokinase is not subject to short-term regulation by glucose. These observations are consistent with the view that phosphofructokinase is the rate-limiting enzyme of glycolysis in intestinal mucosa and account for the fact that the rate of glucose utilization by rat small intestine is not very responsive to changes in the concentration of glucose in the lumen.
| S-EPMC1153360 | biostudies-other
Project description:1. The preparation of gram quantities of isolated epithelial-cell ;ghosts' from mucosal scrapings of rat small intestine is described. The method involves dispersing the tissue by gentle homogenization in 6% dextran in Krebs-Ringer phosphate, pH7.4, followed by filtration through nylon cloth and sedimentation by low-speed centrifuging. 2. The isolated epithelial-cell ;ghosts' contained all of the DNA, but only 52% of the protein and 53-57% of the RNA of the original homogenate. They contained most of the activity of the following enzymes found in the homogenate: aminopeptidase (71%); alkaline beta-glycerophosphatase (82%); invertase (92%); adenosine triphosphatase (93-116%); acid beta-glycerophosphatase (83%); nonspecific esterase (76%); succinate dehydrogenase (96%). Only small proportions of the total lactate-dehydrogenase (10%) and phosphoglucose-isomerase (2%) activities found in the homogenate were recovered in the isolated cell ;ghosts'. 3. The epithelial-cell ;ghost' preparation did not respire unless cofactors and substrates were added, and did not consume glucose or produce lactic acid from glucose. 4. The effect of varying the composition of the homogenization medium was studied. Concentrations of dextran (mol.wt. 15x10(4)) from 1 to 12%, solutions of dextrans (all at 6%) with mol.wt. varying between 3.6x10(4) and 2x10(6), and a solution of 8% polyethylene glycol (mol.wt. 4000) served equally well for the production of epithelial-cell ;ghosts'. Two of these solutions, however, 12% dextran (mol.wt.15x10(4)) and 6% dextran (mol.wt. 2x10(6)), were too viscous to allow the complete sedimentation of the cell ;ghosts' at low relative centrifugal forces. Omission of either Krebs-Ringer phosphate or dextran from the medium resulted in almost complete cell breakage during the homogenization. 5. The isolated cell ;ghosts' were used as a starting material for subcellular fractionation of rat intestinal mucosa by differential centrifugation. The distributions of protein and succinate-dehydrogenase activity among the fractions were compared with corresponding values in fractions isolated by differential centrifugation of mucosa homogenized in 0.3m-sucrose-5mm-EDTA, pH7.4. The method in which cell ;ghosts' were used as starting material gave a better separation and cleaner fractions than the method in which untreated mucosal scrapings were used.
| S-EPMC1207073 | biostudies-other
Project description:In epithelial cells isolated from rat small intestine, we have studied the influence of vasoactive intestinal peptide (VIP), a neurotransmitter which markedly increases enterocyte cyclic AMP, and of two cyclic AMP analogues (8-bromo cyclic AMP and N6,2'-O-dibutyryl cyclic AMP) on the rate of glycolysis, fructose 2,6-bisphosphate concentration and 6-phosphofructo-2-kinase activity, as well as on the rate of 3-O-methyl-D-[14C]glucose uptake. Our results show that, without affecting the rate of 3-O-methyl-D-[14C]glucose accumulation, VIP and cyclic AMP analogues were able to inhibit glucose consumption and L-lactate formation by isolated rat enterocytes. These effects occurred parallel to a significant decrease in the cellular concentration of fructose 2,6-bisphosphate and to a partial inactivation of 6-phosphofructo-2-kinase. These findings support the hypothesis that VIP inhibits glycolysis in rat enterocytes through a cyclic AMP-dependent mechanism.
| S-EPMC1133281 | biostudies-other
Project description:Experiment description 1. Experimental design 1) Authors, laboratory, and contact: Xue-Lin Cui1, Patricia Soteropoulos2, Peter Tolias2, Ronaldo P. Ferraris1: 1Dept. of Pharmacology and Physiology, UMDNJ-New Jersey Medical School, Newark, NJ 07103-2714, 2Center for Applied Genomics, PHRI, 225 Warren Street Newark, NJ 07103-3506. Contact to Dr. Ronaldo P. Ferraris. 2) Type of the experiment: treated vs. untreated comparison. 3) Experimental factors: Twenty to twenty-two old SD rats were use in the experiment. The intestines of paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 4-h or 20-min, respectively. 4) Totally 14 experiments were done. 5) A common reference was not used for all the hybridizations. 6) Quality control steps ( 14) Miller RA, Galecki A, Shmookler-Reis RJ. Interpretation, design, and analysis of gene array expression experiments. J Gerontol A Biol Sci Med Sci. 2001 Feb;56(2):B52-7. (15) Tseng GC, Oh MK, Rohlin L, Liao JC, Wong WH. Issues in cDNA microarray analysis: quality filtering, channel normalization, models of variations and assessment of gene effects. Nucleic Acids Res. 2001 Jun 15;29(12):2549-57. ( 16) Yang YH, Speed T. Design issues for cDNA microarray experiments. Nat Rev Genet. 2002 Aug;3(8):579-88. (17) Yang YH, Dudoit S, Luu P, Lin DM, Peng V, Ngai J, Speed TP. Normalization for cDNA microarray data: a robust composite method addressing single and multiple slide systematic variation. Nucleic Acids Res. 2002 Feb 15;30(4):e15.): a) In the 4 h perfusion experiment, the intestines of the paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 4-h, respectively. Totally five replicates were conducted. The RNA samples were extracted from HF- and HG-perfused intestines (n=5 pairs) then labelled with Cy 5 (HF1, HF2, HF3, HF4, and HF5) and Cy 3 (HG1, HG2, HG3, HG4, and HG5), respectively. At the same time, one dye swap experiment, in which the samples extracted from HF- and HG-perfused intestines were labelled with Cy 3 (HF1) and Cy 5 (HG1), respectively, was done and used in the data analysis. b) In the 20 min perfusion experiment, the intestines of of the paired pups were perfused with 100 mM fructose (HF) and 100 mM glucose (HG) for 20-min, respectively. Totally four replicates were conducted. In two of the four-replicate experiments, the samples extracted from HF- and HG-perfused intestines were labelled with Cy 5 (HF1a and HF3a) and Cy 3 (HG1a and HG3a), respectively. In the other two of the four-replicate experiments, the dye was swapped, that is, the samples extracted from HF- and HG-perfused intestines were labelled with Cy 3 (HF2a and HF4a) and Cy 5 (HG2a and HG4a), respectively. c) Three self-self experiments using different samples (HF1, HG1, and HF2) and one capture primer alone experiment were conducted to eliminate the false positive genes and aid to analyze the data. 7) The goal of the experiment: Fructose induced the expression of GLUT5 mRNA in the small intestinal epithelial cells. But it is not clear about the mechanisms involved in the phenomenal. In this experiment, we hypothesize: the expression of some genes must be changed after fructose perfusion for 4-h, these genes may regulate GLUT5 gene transcription; the expression of some genes must be changed even after 20-min fructose perfusion, these genes may trigger the GLUT5 gene expression as early response gene. Our goal in this study is to find out these potencial gene. 8) Links (URL), citations 2. Samples used, extract preparation, labeling and hybridization 1) Bio-source properties a) Sprague Dawley rats (NCBI taxonomy); b) The rat was anesthetized using urathene. The rat body was kept at 37 oC under light. c) Descriptors relevant to the particular sample: the jejunum of the 20-d old rat pups (unknown sex) was perused. 2) Biomaterial manipulations: the jejunum was in vivo perfused with 100 mM HF or HG for 4-h or 20-min. At the end of each experiment, the jejunum was immediately cut out and snap frozen in liqued nitrogen, and then stored the tissue in -80 oC freezer. 3) RNA isolation: A RNeasy Midi Kit (QIAGEN Inc., Valencia, CA) was used to extract total RNA from the jejunum. The brief procesure is described in the Total RNA Extraction for RT-PCR and Microarray above. 4) Sample assignment to slides for labeling and hybridization: S1: HF1(Cy 5) vs HG1 (Cy 3); S2: HF2 (Cy 5) vs HG2 (Cy 3); S3: HF3 (Cy 5) vs HG3 (Cy 3); S4: HF4 (Cy 5) vs HG4 (Cy 3); S5: HF5 (Cy 5) vs HG5 (Cy 3); S6: HF2 (Cy 3) vs HG2 (Cy 5); S7: HF1a (Cy 5) vs HG1a (Cy 3); S8: HF3a (Cy 5) vs HG3a (Cy 3); S9: HF2a (Cy 3) vs HG2a (Cy 5); S10: HF4a (Cy 3) vs HG4a (Cy 5); S11: HG1 (Cy 5) vs HG1 (Cy 3); S12: HG3 (Cy 5) vs HG3 (Cy 3); S13: HF3 (Cy 5) vs HF3 (Cy 3); S14: Cy 3 vs Cy 5 capture primer. 5) Labeling and hybridization procedures and parameters: The 3DNA Submicro Oligo Expression Array Detection Kit (Genisphere Inc., Hatfield, PA) was employed to synthesize and label the complimentary DNA (cDNA) with fluorescent dye: Cy3 or Cy5. The reason why this indirect labeling method was chosen is based on a previous study which demonstrated that the method was more sensitive and consistent than direct labeling method or other indirect techniques like aminoallyl labeling method and MICROMAX tyramide signal amplification labeling method. (18)Yu J, Othman MI, Farjo R, et al: Molecular Vision 2002; 8:130-137). In the primary experiments, three, four, and five g of total RNA were tested for labeling and hybridization conditions. In the official experiments, four g of total RNA isolated from each sample were used for labeling and hybridization, because the signal to noise ratio is high at this concentration. In addition, at this concentration, all most of the low expressed genes are detectable and the highly expressed genes are not fully saturated. The procedure was conducted following the manufacturer's protocol. Briefly, the first strand cDNA was synthesized using a specific poly T Cy3 RT primer or a specific poly T Cy5 RT primer in different tubes for paired samples. Combine the Cy3 and Cy5 reactions in one tube and precipitate the sample in ethanol. After briefly drying the pellet, resuspend the pellet with 40 l of hybridization buffer. Subsequently, apply the hybridization mixture onto the array slide and hybridize overnight at 55 oC in a humidified chamber. Following the hybridization, the slides were washed by placing them into 50 ml conical tubes containing 2 x SSC, 0.2% SDS for 15 min, 2 x SSC for 10 min, 0.2 x SSC for 10 min, and 95% ethanol for 1 min all at room temperature, except for the first wash, in which the temperature was 42 oC. After drying the slides, the Cy3 and Cy5 capture (connected to dye molecues) reagents mixed in hybridization buffer was pipeted onto the slides, and then hybridize at 65 oC for 3 h following slides wash as described above. 3. Measurement data and spesifications of data processing 1) Raw data description Slides were scanned for Cy3 and Cy5 fluorescence using an Axon GenePix4000 microarray reader (GenePix 4000A, Axon instruments, Foster City, CA) and quantitated using GenePix software. Scan parameters: Scan power: Cy 3 : Cy 5 = 100:100; Laser power: Cy 3 : Cy 5 = 1.15:1.76; Spatial resolution: ???; Pixel size: 10 or 100 ???; Pixel number: F pixels: 50-100; B pixels: 400-500 ???; PMT voltage: 600-750 for Cy 5 channel, 650-850 for Cy 3 channel. 2) Image analysis and quantitation For the image analysis, the density of the spots was detected using Gene Spring (Silicon Genetics, Redwood City, CA) software (GeniPix 4.0) (19) Axon Instruments Inc. (1999) GenePix 4000A User's Guide. Axon Instruments, Union City, CA). It is commercially available. Description of the algorithm and all the parameters used: R = red channel signal = F635; G = green channel signal = B 532; M = log2(R/G); A = 1/2xlog2(RxG); User-difined parameter f = 40%. For the complete image analysis out put of each image, see the NCBI's GEO database (www.ncbi.nlm.nih.gov/geo). 3) Normalized and summarized data-gene expression data matrix For the normalization, the following two steps were taken. a) When measuring the density of the spots using Gene Spring software, the ratio of Cy 3 and Cy 5 dyes was adjusted as 1 as a globle normalization for the whole slide. b) For the gene expression analysis, the results (midian of the density of the pixel in one spot was used) were normalized by a LOWESS (locally weighed scatter smoother) software provided by the Center for Applied Genomics, so that the results can be compared among the experiments performed at different times. (20)Yang YH, Dudoit S, Luu P, Lin DM, Peng V, Ngai J, Speed TP. Normalization for cDNA microarray data: a robust composite method addressing single and multiple slide systematic variation. Nucleic Acids Res. 2002 Feb 15;30(4):e15.). c) The following rules were made to decide the genes that were significantly changed: 1) Eliminate the genes with high density (over than 2X of background) in the 3DNA capture probe experiments; 2) Eliminate the genes with density lower than 2X of background ( 21) Lee HM, Greeley GH Jr, Englander EW. Age-associated changes in gene expression patterns in the duodenum and colon of rats. Mech Ageing Dev. 2001 Apr 15;122(4):355-71.); 3) Eliminate the genes with change over than 1.5X in dye flip-over experiment; 4) Eliminate the genes with opposite results in one experiments between dye flip-over comparisons; 5) Only the genes significantly changed over 3 in 5 comparisons in 4 h perfusion experiment and over 2 in 4 comparisons in 20 min perfusion experiment were considered as reliable and biologically important. d) The final results discribed in this paper were presented as Means + SE and the frequency of gene changed in the HF-perfused intestine. About the image, raw, and normalized data, and other detailed parameters, please see the gene expression data tables derived from the experiments in the NCBI's GEO database. The design for the dye labeling in this experiments is as the follows: 1) 5 comparisons were conducted in the 4 h-perfused HG vs HF experiment, in which in 3 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy3 and Cy5, respectively; and in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy5 and Cy3, respectively. 2) 4 comparisons were conducted in the 20 min-perfused HG vs HF experiment, in which in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy3 and Cy5, respectively; and in 2 comparisons, the cDNA samples synthesized from HG- and HF-perfused intestines were labeled with Cy5 and Cy3, respectively. 3) 3 dye flip-over experiments using 1 RNA sample extracted from HF-perfused intestine and 2 samples extracted from HG-perfused intestines were performed to eliminate the false positive results induced by the dye labeling technique or other unsolved problems. 4) 2 experiments only applying 3DNA fluorescent probe, which is connected to complementary capture sequence, were performed to eliminate the false positive genes that were low expressed in the tissue. The procedures for synthesizing the first strand cDNA, labeling the cDNA, hybridizaion, and detecting the signals were performed following the manufacturer's protocols. Keywords: other
2004-01-28 | GSE996 | GEO
Project description:Intestinal epithelial cells (IECs) overlying the villi play a prominent role in absorption of digested nutrients and establish a barrier that separates the internal milieu from potentially harmful microbial antigens. Several mechanisms by which antigens of dietary and microbial origin enter the body have been identified; however whether IECs play a role in antigen uptake is not known. Using in vivo imaging of the mouse small intestine, we investigated whether epithelial cells (enterocytes) play an active role in the uptake (sampling) of lumen antigens. We found that small molecular weight antigens such as chicken ovalbumin, dextran, and bacterial LPS enter the lamina propria, the loose connective tissue which lies beneath the epithelium via goblet cell associated passageways. However, epithelial cells overlying the villi can internalize particulate antigens such as bacterial cell debris and inert nanoparticles (NPs), which are then found co-localizing with the CD11c+ dendritic cells in the lamina propria. The extent of NP uptake by IECs depends on their size: 20-40 nm NPs are taken up readily, while NPs larger than 100 nm are taken up mainly by the epithelial cells overlying Peyer's patches. Blocking NPs with small proteins or conjugating them with ovalbumin does not inhibit their uptake. However, the uptake of 40 nm NPs can be inhibited when they are administered with an endocytosis inhibitor (chlorpromazine). Delineating the mechanisms of antigen uptake in the gut is essential for understanding how tolerance and immunity to lumen antigens are generated, and for the development of mucosal vaccines and therapies.
| S-EPMC3903549 | biostudies-literature