In vivo absorption of water and electrolytes in mouse intestine. Application to villin −/− mice

2002 ◽  
Vol 282 (4) ◽  
pp. G634-G639 ◽  
Author(s):  
Rafika Athman ◽  
Annick Tsocas ◽  
Olivier Presset ◽  
Sylvie Robine ◽  
Claude Rozé ◽  
...  
Keyword(s):  
Wild Type ◽  
Single Pass ◽  
Perfusion Method ◽  
Mixed Genetic Background ◽  
Pass Perfusion ◽  
Mouse Small Intestine ◽  
In Vivo Absorption ◽  
Measured Absorption ◽  
Mouse Intestine

This study was done to establish and validate a single-pass perfusion method for measuring the absorption of water and electrolytes by the mouse small intestine. The method was then used to study intestinal absorption in mice whose villin gene had been invalidated ( v−/−). The single-pass perfusion of the jejunum measures the absorption of water, Cl−, Na+, K+, HCO[Formula: see text], and glucose in anesthetized wild-type and v−/− mice in vivo. We measured absorption under basal and stimulated conditions (carbachol, vasoactive intestinal polypeptide, intralumen PGE2). Basal absorption and stimulated secretions were similar to those previously obtained in rats. There was no difference between wild-type and v−/− mice in animals with mixed genetic background or in pure C57BL6 mice. We conclude that this in vivo perfusion method is suitable for studying the absorption/secretion of electrolytes in the mouse intestine and that a lack of villin does not significantly alter basal and secretagogue-stimulated electrolyte movements across the epithelium of the mouse jejunum in vivo.

scholarly journals MetR-Regulated Vibrio cholerae Metabolism Is Required for Virulence

mBio ◽  
2012 ◽  
Vol 3 (5) ◽  
Author(s):  
Ryan W. Bogard ◽  
Bryan W. Davies ◽  
John J. Mekalanos
Keyword(s):  
Amino Acid ◽  
Vibrio Cholerae ◽  
Virulence Factor ◽  
Current Knowledge ◽  
Intestinal Colonization ◽  
Wild Type ◽  
Pathogenic Potential ◽  
Content Type ◽  
Mouse Intestine

ABSTRACTLysR-type transcriptional regulators (LTTRs) are the largest, most diverse family of prokaryotic transcription factors, with regulatory roles spanning metabolism, cell growth and division, and pathogenesis. Using a sequence-defined transposon mutant library, we screened a panel ofV. choleraeEl Tor mutants to identify LTTRs required for host intestinal colonization. Surprisingly, out of 38 LTTRs, only one severely affected intestinal colonization in the suckling mouse model of cholera: the methionine metabolism regulator, MetR. Genetic analysis of genes influenced by MetR revealed thatglyA1andmetJwere also required for intestinal colonization. Chromatin immunoprecipitation of MetR and quantitative reverse transcription-PCR (qRT-PCR) confirmed interaction with and regulation ofglyA1, indicating that misregulation ofglyA1is likely responsible for the colonization defect observed in themetRmutant. TheglyA1mutant was auxotrophic for glycine but exhibited wild-type trimethoprim sensitivity, making folate deficiency an unlikely cause of its colonization defect. MetJ regulatory mutants are not auxotrophic but are likely altered in the regulation of amino acid-biosynthetic pathways, including those for methionine, glycine, and serine, and this misregulation likely explains its colonization defect. However, mutants defective in methionine, serine, and cysteine biosynthesis exhibited wild-type virulence, suggesting that these amino acids can be scavenged in vivo. Taken together, our results suggest that glycine biosynthesis may be required to alleviate an in vivo nutritional restriction in the mouse intestine; however, additional roles for glycine may exist. Irrespective of the precise nature of this requirement, this study illustrates the importance of pathogen metabolism, and the regulation thereof, as a virulence factor.IMPORTANCEVibrio choleraecontinues to be a severe cause of morbidity and mortality in developing countries. Identification ofV. choleraefactors critical to disease progression offers the potential to develop or improve upon therapeutics and prevention strategies. To increase the efficiency of virulence factor discovery, we employed a regulator-centric approach to multiplex our in vivo screening capabilities and allow whole regulons inV. choleraeto be interrogated for pathogenic potential. We identified MetR as a new virulence regulator and serine hydroxymethyltransferase GlyA1 as a new MetR-regulated virulence factor, both required byV. choleraeto colonize the infant mouse intestine. Bacterial metabolism is a prerequisite to virulence, and current knowledge of in vivo metabolism of pathogens is limited. Here, we expand the known role of amino acid metabolism and regulation in virulence and offer new insights into the in vivo metabolic requirements ofV. choleraewithin the mouse intestine.

Platelet-Endothelial Cell Interactions During Ischemia/Reperfusion: The Role of P-Selectin

Blood ◽  
1998 ◽  
Vol 92 (2) ◽  
pp. 507-515 ◽  
Author(s):  
Steffen Massberg ◽  
Georg Enders ◽  
Rosmarie Leiderer ◽  
Simone Eisenmenger ◽  
Dietmar Vestweber ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Ischemia Reperfusion ◽  
Cell Interactions ◽  
Wild Type ◽  
Mouse Small Intestine ◽  
Ligand Interactions ◽  
Selectin Ligand ◽  
Subsequent Activation

Abstract Growing evidence supports a pathophysiological role for platelets during the manifestation of postischemic reperfusion injury; in the current study, we investigated the nature and the molecular determinants of platelet-endothelial cell interactions induced by ischemia/reperfusion (I/R). Platelet-endothelium and leukocyte-endothelium interactions after 1 hour of ischemia were monitored in vivo within mouse small intestine. By intravital fluorescence microscopy, we observed that platelets, like leukocytes, roll along or firmly adhere to postischemic microvascular endothelial cells. In contrast, few leukocyte-endothelial cell interactions were detected in sham-operated controls. Monoclonal antibodies against P-selectin significantly attenuated platelet rolling and adherence in response to I/R. To identify whether platelet or endothelial P-selectin plays the major role in mediating postischemic platelet-endothelial cell interactions, P-selectin-deficient or wild-type platelets were transfused into wild-type or P-selectin-deficient mice, respectively. Whereas platelets lacking P-selectin rolled along or adhered to postischemic wild-type endothelium, interactions between wild-type platelets with mutant endothelium were nearly absent, indicating that I/R-induced platelet-endothelium interactions are dependent on the expression of P-selectin by endothelial cells. Concomitantly, P-selectin expression in the intestinal microvasculature was enhanced in response to I/R, whereas no upregulation of P-selectin was observed on circulating platelets. In summary, we provide first in vivo evidence that platelets accumulate in the postischemic microvasculature early after reperfusion via P-selectin-ligand interactions. Platelet recruitment and subsequent activation might play an important role in the pathogenesis of I/R injury.

HCO3 transport in rat jejunum: relationship to NaCl and H2O transport in vivo.

1977 ◽  
Vol 232 (1) ◽  
pp. E62
Author(s):  
R B Podesta ◽  
D F Mettrick
Keyword(s):  
Cation Exchange ◽  
Rat Jejunum ◽  
Perfusion Technique ◽  
Single Pass ◽  
Physiological Importance ◽  
Pass Perfusion ◽  
Layer Effect ◽  
Disequilibrium Ph ◽  
Precise Degree

HCO3- absorption and its association with Na+ absorption has been studied in the rat jejunum in vivo, using a single-pass perfusion technique. The method of disequilibrium pH, the only valid way of demonstrating jejunal H+ secretion, was used to distinguish between an HCO3- pump and H+ secretion as the mechanism of HCO3- absorption. HCO3- stimulated Na+ absorption; Na+ deletion inhibited HCO3 absorption, decreased luminal acidification, and decreased the level of luminal PCO2. These results confirmed an Na+:H+ cation exchange, the possible mechanism of which is discussed in terms of results using other tissues. Na+-dependent HCO3-absorption made up a larger part of total HCO3-absorption as the luminal HCO3-concentrations diminished, although the precise degree of Na+-dependency could not be determined because of the unstirred layer effect. The mechanism of Na+-independent HCO3-absorption was not established, but it was not affected by PD, Cl-, or H2O movements. Glucose-stimulated and HCO3-stimulated Na+ absorption were less than additive. The physiological importance of HCO3-stimulated Na+ absorption in the acidic postprandial jejunum is probably due entirely to the effect of free CO2 in the lumen.

scholarly journals l-Fucose Stimulates Utilization of d-Ribose by Escherichia coli MG1655 ΔfucAO and E. coli Nissle 1917 ΔfucAO Mutants in the Mouse Intestine and in M9 Minimal Medium

2007 ◽  
Vol 75 (11) ◽  
pp. 5465-5475 ◽  
Author(s):  
Steven M. Autieri ◽  
Jeremy J. Lins ◽  
Mary P. Leatham ◽  
David C. Laux ◽  
Tyrrell Conway ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Minimal Medium ◽  
Wild Type ◽  
E Coli ◽  
Commensal Strain ◽  
Mouse Intestine ◽  
Level 2 ◽  
Growth Experiments

ABSTRACT Escherichia coli MG1655 uses several sugars for growth in the mouse intestine. To determine the roles of l-fucose and d-ribose, an E. coli MG1655 ΔfucAO mutant and an E. coli MG1655 ΔrbsK mutant were fed separately to mice along with wild-type E. coli MG1655. The E. coli MG1655 ΔfucAO mutant colonized the intestine at a level 2 orders of magnitude lower than that of the wild type, but the E. coli MG1655 ΔrbsK mutant and the wild type colonized at nearly identical levels. Surprisingly, an E. coli MG1655 ΔfucAO ΔrbsK mutant was eliminated from the intestine by either wild-type E. coli MG1655 or E. coli MG1655 ΔfucAO, suggesting that the ΔfucAO mutant switches to ribose in vivo. Indeed, in vitro growth experiments showed that l-fucose stimulated utilization of d-ribose by the E. coli MG1655 ΔfucAO mutant but not by an E. coli MG1655 ΔfucK mutant. Since the ΔfucK mutant cannot convert l-fuculose to l-fuculose-1-phosphate, whereas the ΔfucAO mutant accumulates l-fuculose-1-phosphate, the data suggest that l-fuculose-1-phosphate stimulates growth on ribose both in the intestine and in vitro. An E. coli Nissle 1917 ΔfucAO mutant, derived from a human probiotic commensal strain, acted in a manner identical to that of E. coli MG1655 ΔfucAO in vivo and in vitro. Furthermore, l-fucose at a concentration too low to support growth stimulated the utilization of ribose by the wild-type E. coli strains in vitro. Collectively, the data suggest that l-fuculose-1-phosphate plays a role in the regulation of ribose usage as a carbon source by E. coli MG1655 and E. coli Nissle 1917 in the mouse intestine.

scholarly journals Solvent drag in jejunal absorption of salicylic acid and antipyrine obtained by in situ single-pass perfusion method in rat.

1984 ◽  
Vol 7 (4) ◽  
pp. 246-253 ◽  
Author(s):  
TOYOTO HIRASAWA ◽  
TOSHIKO MURAOKA ◽  
AKIRA KARINO ◽  
MASAHIRO HAYASHI ◽  
SHOJI AWAZU
Keyword(s):  
Salicylic Acid ◽  
Solvent Drag ◽  
Jejunal Absorption ◽  
Single Pass ◽  
Perfusion Method ◽  
Pass Perfusion
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