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991.
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Lubarski I Asher C Garty H 《American journal of physiology. Renal physiology》2011,301(6):F1270-F1280
FXYD5 (dysadherin or RIC) is a member of the FXYD family of single-span transmembrane proteins associated with the Na(+)-K(+)-ATPase. Several studies have demonstrated enhanced expression of FXYD5 during metastasis and effects on cell adhesion and motility. The current study examines effects of FXYD5 on the paracellular permeability in the mouse kidney collecting duct cell line M1. Expressing FXYD5 in these cells leads to a large decrease in amiloride-insensitive transepithelial electrical resistance as well as increased permeability to 4-kDa dextran. Impairment of cell-cell contact was also demonstrated by staining cells for the tight and adherence junction markers zonula occludens-1 and β-catenin, respectively. This is further supported by large expansions of the interstitial spaces, visualized in electron microscope images. Expressing FXYD5 in M1 cells resulted in a decrease in N-glycosylation of β1 Na(+)-K(+)-ATPase, while silencing it in H1299 cells had an opposite effect. This may provide a mechanism for the above effects, since normal glycosylation of β1 plays an important role in cell-cell contact formation (Vagin O, Tokhtaeva E, Sachs G. J Biol Chem 281: 39573-39587, 2006). 相似文献
994.
Bucking C Fitzpatrick JL Nadella SR McGaw IJ Wood CM 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(5):615-630
Recent studies focusing on the consequences of feeding for ion and water balance in freshwater fish have revealed the need for similar comparative studies in seawater fish. A detailed time course sampling of gastrointestinal (GI) tract contents following the ingestion of a single meal of a commercial diet revealed the assimilation of both water and dietary ions (Na+, Cl?, K+, Ca2+, Mg2+) along the GI tract of seawater-acclimated rainbow trout (Oncorhynchus mykiss) which had been fasted for 1 week. Consumption of the meal did not change the drinking rate. There was a large secretion of fluid into the anterior intestine and caecae (presumably bile and/or pancreatic secretions). As a result, net assimilation (63%) of the ingested water along the GI tract was lower than generally reported for fasted trout. Mg2+ was neither secreted into nor absorbed from the GI tract on a net basis. Only K+ (93% assimilated) and Ca2+ (43% assimilated) were absorbed in amounts in excess of those provided by ingested seawater, suggesting that dietary sources of K+ and Ca2+ may be important to seawater teleosts. The oesophagus–stomach served as a major site of absorption for Na+, Cl?, K+, Ca2+, and Mg2+, and the anterior intestine and caecae as a major site of net secretion for all of these ions, except Cl?. Despite large absorptive fluxes of these ions, the ionic composition of the plasma was maintained during the digestion of the meal. The results of the present study were compared with previous work on freshwater-acclimated rainbow trout, highlighting some important differences, but also several similarities on the assimilation of water and ions along the gastrointestinal tract during digestion. This study highlights the complicated array of ion and water transport that occurs in the intestine during digestion while revealing the importance of dietary K+ and Ca2+ to seawater-acclimated rainbow trout. Additionally, this study reveals that digestion in seawater-acclimated rainbow trout appears to compromise intestinal water absorption. 相似文献
995.
Glover CN Bucking C Wood CM 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2011,181(6):765-771
This study utilised an in vitro technique to characterise absorption of two amino acids across the intestinal epithelium of
Pacific hagfish, Eptatretus stoutii. Uptake of l-alanine and glycine conformed to Michaelis–Menten kinetics. An uptake affinity (K
m; substrate concentration required to attain a 50% uptake saturation) of 7.0 mM and an uptake capacity (J
max) of 83 nmol cm−2 h−1 were described for l-alanine. The K
m and J
max for glycine were 2.2 mM and 11.9 nmol cm−2 h−1, respectively. Evidence suggested that the pathways of l-alanine and glycine absorption were shared, and sodium dependent. Further analysis indicated that glycine uptake was independent
of luminal pH and proline, but a component of uptake was significantly impaired by 100-fold excesses of threonine or asparagine.
The presence of a short-term (24 h) exposure to waterborne glycine, similar in nature to that which may be expected to occur
when feeding inside an animal carcass, had no significant impact on gastrointestinal glycine uptake. This may indicate a lack
of cross talk between absorptive epithelia. These results are the first published data to describe gastrointestinal uptake
of an organic nutrient in the oldest extant vertebrate and may provide potential insight into the evolution of nutrient transport
systems. 相似文献
996.
Lin A Nguyen L Lee T Clotilde LM Kase JA Son I Carter JM Lauzon CR 《Journal of microbiological methods》2011,87(1):105-110
Identification and serotyping of Shiga toxin-producing Escherichia coli during foodborne outbreaks can aid in matching clinical, food, and environmental isolates when trying to identify the source of illness and ultimately food contamination. Herein we describe a Luminex microbead-based suspension array to identify the O serogroup of the ten most clinically relevant STECs: O26, O45, O91, O103, O111, O113, O121, O128, O145, and O157. The use of PCR followed by Luminex xMAP® technology enables the detection of multiple analytes in a single multiplex reaction with high throughput capabilities. One hundred and fourteen STEC isolates were correctly identified with no false positives among forty-six other organisms using this assay. Assay performance was tested in multiple laboratories using a panel of eleven different STEC serogroups on the Bio-Plex 200 and MAGPIX instruments. The STEC microbead-based suspension array can be performed in a 96-well plate format for high throughput screening in less than 4 h. Furthermore, it is expandable, allowing for the addition of O serogroups should the need arise. 相似文献
997.
de la Motte CA 《American journal of physiology. Gastrointestinal and liver physiology》2011,301(6):G945-G949
The causes of fibrosis, or the inappropriate wound healing, that follows chronic intestinal inflammation are not well defined and likely involve the contributions of multiple cellular mechanisms. As other articles in this series confirm, inflammatory cytokines clearly play a role in driving cell differentiation to the myofibroblast phenotype, promoting proliferation and extracellular matrix deposition that are characteristic of fibrotic tissue. However, controlling the balance of cytokines produced and process of myofibroblast differentiation appears to be more complex. This review considers ways in which hyaluronan, an extracellular matrix component that is remodeled during the progression of colitis, may provide indirect as well as direct cues that influence the balancing act of intestinal wound healing. 相似文献
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Ranjit S Khair L Linehan EK Ucher AJ Chakrabarti M Schrader CE Stavnezer J 《Journal of immunology (Baltimore, Md. : 1950)》2011,187(5):2464-2475
Activation-induced cytidine deaminase (AID) is induced in B cells during an immune response and is essential for both class-switch recombination (CSR) and somatic hypermutation of Ab genes. The C-terminal 10 aa of AID are required for CSR but not for somatic hypermutation, although their role in CSR is unknown. Using retroviral transduction into mouse splenic B cells, we show that the C terminus is not required for switch (S) region double-strand breaks (DSBs) and therefore functions downstream of DSBs. Using chromatin immunoprecipitation, we show that AID binds cooperatively with UNG and the mismatch repair proteins Msh2-Msh6 to Ig Sμ and Sγ3 regions, and this depends on the C terminus and the deaminase activity of AID. We also show that mismatch repair does not contribute to the efficiency of CSR in the absence of the AID C terminus. Although it has been demonstrated that both UNG and Msh2-Msh6 are important for introduction of S region DSBs, our data suggest that the ability of AID to recruit these proteins is important for DSB resolution, perhaps by directing the S region DSBs toward accurate and efficient CSR via nonhomologous end joining. 相似文献