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Query: UNIPROT:P06889 (Mol)
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The lectin concanavalin A (ConA) when applied to the olfactory mucosa (OM) of frog and rat, is reported to partially inhibit electro-olfactogram (EOG) responses to fatty acid odours. Control odours like isoamyl acetate were not affected. We have now studied in the frog whether this treatment affects the corresponding olfactory bulb (OB) response. The OB surface was impregnated with a voltage-sensitive dye (RH 414). Spatial and temporal patterns of odour response were measured by changes in dye fluorescence that occur when OB neurons fire. The apparatus, consisted of an epi-fluorescent microscope coupled to a 64 x 64 pixel CCD photodetection camera. This allowed imaging over an 0.9 mm2 area of the OB glomerular layer to high resolution. When the frog OM was bathed with 5 mg ml(-1) ConA in Ringer's solution, the n-butyric acid odour response in the OB largely disappeared while the isoamyl acetate response did not change. When this experiment was repeated in the presence of 20 mM methyl alpha-D mannopyranoside (a ConA inhibitor), ConA failed to inhibit the n-butyric acid response. Moreover the ConA effect was partially reversible. A Ringer's wash of the OM after ConA treatment, partially restored the OB response to n-butyric acid. Thus the olfactory bulb results seem compatible with the EOG results and reinforce the notion that ConA selectively prevents n-butyric acid sensitive olfactory receptor neurons from firing. Chemical modification of the OM and their effect on OB response patterns may provide a useful approach to investigate olfactory quality coding.
Cell Mol Biol (Noisy-le-grand) 1999 May
PMID:Selective and reversible blockage of a fatty acid odour response in the olfactory bulb of the frog (Rana temporaria). 1038 90

We hypothesized that the requirement for Ca(2+)-dependent exocytosis in cell-membrane repair is to provide an adequate lowering of membrane tension to permit membrane resealing. We used laser tweezers to form membrane tethers and measured the force of those tethers to estimate the membrane tension of Swiss 3T3 fibroblasts after membrane disruption and during resealing. These measurements show that, for fibroblasts wounded in normal Ca(2+) Ringer's solution, the membrane tension decreased dramatically after the wounding and resealing coincided with a decrease of approximately 60% of control tether force values. However, the tension did not decrease if cells were wounded in a low Ca(2+) Ringer's solution that inhibited both membrane resealing and exocytosis. When cells were wounded twice in normal Ca(2+) Ringer's solution, decreases in tension at the second wound were 2.3 times faster than at the first wound, correlating well with twofold faster resealing rates for repeated wounds. The facilitated resealing to a second wound requires a new vesicle pool, which is generated via a protein kinase C (PKC)-dependent and brefeldin A (BFA)-sensitive process. Tension decrease at the second wound was slowed or inhibited by PKC inhibitor or BFA. Lowering membrane tension by cytochalasin D treatment could substitute for exocytosis and could restore membrane resealing in low Ca(2+) Ringer's solution.
Mol Biol Cell 2000 Dec
PMID:A decrease in membrane tension precedes successful cell-membrane repair. 1110 27

Desiccation and thermal stress are among the primary factors limiting terrestriality in crustaceans. Water loss was estimated as weight change in five sympatric species of Uca from south Texas for periods up to 7 hr in dry air. Simultaneously, corporal temperature was measured with a thermocouple placed under the carapace. To estimate integumental permeability to water, 115 mm2 portions of dorsal carapace were glued to U-shaped tubes containing a crab Ringer's solution. These were exposed to dry air and water permeability was estimated from weight change. In whole-animal studies, most rapid weight loss occurred in the first 5 min of exposure to dry air as the body temperature fell below ambient (25 degrees C) in all species. The three most terrestrial species exhibited significant survival over more aquatic congeners after prolonged desiccation. The greatest rate of water loss was observed in Uca subcylindrica which lost 22.9+/-3.0% body weight. Uca panacea and Uca spinicarpa lost 14.1+/-1.6% and 18.5+/-1.8%, respectively. Based on blood osmolarity changes, Uca longisignalis and Uca rapax were more resistant to water loss than Uca subcylindrica under these conditions. Water loss from sections of the dorsal carapace were highest in Uca spinicarpa (10.4 mg/hr/cm2) and Uca longisignalis (8.9 mg/ hr/cm2). Uca subcylindrica and Uca panacea were intermediate (4.5 and 4.2 mg/hr/cm2) while Uca rapax expressed the lowest value (2.9 mg/hr/cm2). These observations support the notion that water loss can effectively lower body temperature in fiddler crabs. However, an inverse relationship between terrestriality and integumental permeability was not evident in these sympatric congeners. Ultimately a balance between physiological and behavioral mechanisms must be achieved for adaptation to the semi-arid habitats in south Texas.
Comp Biochem Physiol A Mol Integr Physiol 1998 Jan
PMID:Evaporative water loss, corporal temperature and the distribution of sympatric fiddler crabs (Uca) from south Texas. 1125 95

The influence of acclimation to seawater (SW) and growth hormone (GH) administration on immune functions was examined in the rainbow trout (Oncorhynchus mykiss). After 3 days acclimation to dilute SW (12 parts per thousand, ppt), an increase in plasma lysozyme activity was observed compared to the fish kept in fresh water (FW). No change was seen in plasma immunoglobulin M (IgM) levels. When they were transferred from dilute SW to full-strength SW (29 ppt) after a single intra-peritoneal injection of ovine or salmon GH, plasma sodium levels of GH-treated fish were significantly lower than those of the control fish injected with Ringer's solution 24 h after the transfer. The plasma level of IgM was not influenced by GH injection in the fish kept in FW nor in those transferred to SW. The administration of GH increased plasma lysozyme activity in the fish in FW, but no further increase was seen after SW transfer. The production of superoxide anions in peripheral blood leucocytes was stimulated by GH in both FW and SW. These results suggest that GH is involved in the stimulation of the non-specific immune functions in SW-acclimated salmonids.
Comp Biochem Physiol B Biochem Mol Biol 2001 Jun
PMID:Stimulation of non-specific immune functions in seawater-acclimated rainbow trout, Oncorhynchus mykiss, with reference to the role of growth hormone. 1139 7

Kidney-targeted gene transfer is expected to revolutionize the treatment of renal diseases. Recently, we demonstrated that naked plasmid deoxyribonucleic acid (DNA) can be transferred into renal interstitial fibroblasts near the peritubular capillaries (PTCs) in normal rats, by retrograde injection into the renal vein with the renal vein and artery clamped. The PTC network is a main target of kidney transplant rejection and of progressive tubulointerstitial fibrosis, which typifies all progressive renal diseases. We retrogradely injected a lacZ expression plasmid in Ringer's solution into the renal vein of rats using a 24-gage catheter. We detected lacZ expression exclusively in the interstitial fibroblasts near the PTCs of the kidney by immunoelectron microscopy. Nephrotoxicity from the gene transfer was not apparent. We then used a rat erythropoietin (Epo) expression plasmid vector pCAGGS-Epo in a reporter assay. We obtained maximal Epo expression when the DNA solution was injected within 5 s in a volume of 1.0 mL. We detected transgene-derived Epo messenger ribonucleic acid by reverse transcriptase polymerase chain reaction only in the kidneys receiving pCAGGS-Epo. In this article, protocols for naked plasmid DNA transfer into rat kidney using this hydrodynamics-based transfection method and the immunoelectron microscopic technique to determine the lacZ gene transfer site are described in detail.
Mol Biotechnol 2004 May
PMID:Rat kidney-targeted naked plasmid DNA transfer by retrograde injection into the renal vein. 1512 45

Blood flow and shear forces are considered to be important parameters possibly stimulating angiogenesis or cardiovascular remodeling. The main objective of this study was to test the hypothesis that a significant reduction in shear forces as a consequence of a significant isovolemic anemia induced by microsurgical techniques during early larval development of the zebrafish might induce a compensatory stimulation of erythropoiesis and/or induce a modification of cardiac activity or even the formation of the heart and may influence the shaping of the vascular bed. Blood from 2 day old zebrafish larvae was withdrawn and replaced by zebrafish Ringer's solution, so that the blood cell concentration was reduced by at least 75%. At 5 days post fertilization (dpf) a partial recovery in blood cell concentration was observed and reached a value of 814.55+/-85.42 cells/nL, while in control animals blood cell concentration amounted to 1856.00+/-131.59 cells/nL. At 7 dpf the value of blood cell concentration was 1023.89+/-95.75 cells/nL versus 1701.54+/-146.03 cells/nL in control animals. Compared to control animals, heart rate and cardiac output were significantly reduced in anemic animals and alterations in the formation of the vascular bed were also observed. A significant decrease in the end-diastolic volume suggested that ventricular volume was reduced. Thus, within a few days zebrafish larvae were nearly able to compensate for an isovolemic anemia by an enhanced erythropoiesis. However, several changes in cardiovascular system indicated that phenotypic plasticity is established even at an early developmental stage.
Comp Biochem Physiol A Mol Integr Physiol 2007 Mar
PMID:How does blood cell concentration modulate cardiovascular parameters in developing zebrafish (Danio rerio)? 1719 57

Transepithelial potential (V(T)), conductance (G(T)), and water flow (J(V)) were measured simultaneously with good time resolution (min) in isolated toad (Bufo bufo) skin epithelium with Ringer on both sides. Inside application of 5 microM isoproterenol resulted in the fast increase in G(T) from 1.2+/-0.3 to 2.4+/-0.4 mS x cm(-2) and slower increases in equivalent short circuit current, I(SC)(Eqv) = -G(T) x V(T), from 12.7+/-3.2 to 33.1+/-6.8 microA cm(-2), and J(V) from 0.72+/-0.17 to 3.01+/-0.49 nL cm(-2) s(-1). Amiloride in the outside solution abolished I(SC)(Eqv) (-1.6+/-0.1 microA cm(-2)) while J(V) decreased to 0.50+/-0.15 nL cm(-2) x s(-1), which is significantly different from zero. Isoproterenol decreased the osmotic concentration of the transported fluid, C(osm) approximately 2 x I(SC)(Eqv)/J(V), from 351+/-72 to 227+/-28 mOsm (Ringer's solution: 252.8 mOsm). J(V) depicted a saturating function of [Na+]out in agreement with Na+ self-inhibition of ENaC. Ouabain on the inside decreased I(SC)(Eqv) from 60+/-10 to 6.1+/-1.7 microA cm(-2), and J(V) from 3.34+/-0.47 to 1.40+/-0.24 nL cm(-2) x s(-1). Short-circuited preparations exhibited a linear relationship between short-circuit current and J(V) with a [Na+] of the transported fluid of 130+/-24 mM ([Na+]Ringer's solution = 117.4 mM). Addition of bumetanide to the inside solution reduced J(V). Water was transported uphill and J(V) reversed at an excess outside osmotic concentration, deltaC(S,rev) = 28.9+/-3.9 mOsm, amiloride decreased deltaC(S,rev) to 7.5+/-1.5 mOsm. It is concluded that water uptake is accomplished by osmotic coupling in the lateral intercellular space (lis), and hypothesized that a small fraction of the Na+ flux pumped into lis is recirculated via basolateral NKCC transporters.
Comp Biochem Physiol A Mol Integr Physiol 2007 Sep
PMID:Beta-adrenergic activation of solute coupled water uptake by toad skin epithelium results in near-isosmotic transport. 1728 36

Hemoglobin (Hb)-based oxygen carriers (HBOCs) are being developed as a potential therapy for increasing tissue oxygenation, yet they have not reached their full potential because of unwanted hemodynamic side effects (vasoconstriction, low cardiac output, and oxygen delivery) due in part to nitric oxide (NO) scavenging by cell-free Hb. It may be possible to overcome the NO scavenging effect by coinfusing S-nitrosylated (SNO) HBOC along with unmodified HBOC. SNO-HBOC, like free Hb, may act as an NO donor in low-oxygen conditions. We hypothesized that an unaltered HBOC, polymerized bovine Hb (PBvHb), coinfused with an SNO-PBvHb, would improve hemodynamics and oxygen delivery during hypoxia. Vascular oxygen content and hemodynamics were determined after euvolemic rats were infused (3 ml) with lactated Ringer's solution, PBvHb, SNO-PBvHb, or PBvHb plus SNO-PBvHb (1:10) during normoxia or acute hypoxia (fraction of inspired oxygen = 10%, 120 min). Hemodynamic side effects resulting from PBvHb infusion (vasoconstriction, elevated pulmonary blood pressure, and reduced cardiac output) were offset by SNO-PBvHb in acute hypoxic, but not normoxic, conditions. These data support the potential use of HBOC mixed with SNO-HBOC for the treatment of conditions in which acute hypoxia is present, such as tumor oxygenation, wound healing, hemorrhagic trauma, and sickle cell and hemolytic anemia.
Am J Respir Cell Mol Biol 2010 Feb
PMID:Mixed S-nitrosylated polymerized bovine hemoglobin species moderate hemodynamic effects in acutely hypoxic rats. 1939 80

The in vitro biocompatibility of decellularized bone marrow extracellular matrix was evaluated. Following a freeze-thaw cycle, sectioned discs of fresh frozen rat metaphyseal bone were sequentially incubated in solutions of hypertonic, then hypotonic Ringer's solution, followed by deoxycholic acid, then DNAase I. The adequacy of decellularization of marrow stroma was examined by light microscopy. Marrow stromal fibroblastic cells were harvested by dispersion of rat long bone marrow, followed by concentration by discontinuous Ficoll-Paque gradient centrifugation. The fibroblastic cells were expanded by in vitro cultivation, and second passage cells were cryopreserved until needed. Cryopreserved marrow stromal cells were applied dropwise to sections of decellularized bone marrow extracellular matrix, and cultured in BJGb medium with 20% fetal bovine serum for ten days. Mature cultures were formalin fixed, decalcified, and embedded in paraffin. Light microscopy of hematoxylin and eosin stained sections showed individual spindle cells invading the upper portion of the decellularized extracellular matrix, and also a monolayer of spindle cells on the upper surfaces of exposed trabecular and cortical bone. This experiment showed that decellularized marrow extracellular matrix is a biocompatible three dimensional in vitro substrate for marrow stromal fibroblastic cells.
Exp Mol Pathol 2010 Feb
PMID:Marrow stromal fibroblastic cell cultivation in vitro on decellularized bone marrow extracellular matrix. 1977 36

Many studies have implicated cell-surface lectins in heterologous cell-cell adhesion, but little is known about the participation of lectins in cellular adhesion in homologous cells. Here, we show the development of a cell model for investigating the direct role of a cell-surface lectin in homologous cell-cell adhesion. Parenchymal cells were isolated from caprine liver using a perfusion buffer, and dispersed in a chemically defined modified Ringer's solution. These cells undergo autoagglutination in the presence of Ca(2+). The autoagglutinated cells can be dissociated specifically with D-galactose (50 mM), which also inhibits the liver cell autoagglutination event. The blood serum protein fetuin has no effect on liver cell autoagglutination, whereas desialylated fetuin (100 microM), with its terminal D-galactose residue, showed a high affinity for blocking the autoagglutination event. The data demonstrates the occurrence of a Ca(2+)-dependent D-galactose-specific lectin and a lectin receptor on the parenchymal cells. Furthermore, it shows that the observed autoagglutination event is caused by the interaction of the cell-surface lectin with its receptor on the neighbouring homologous cells. The data supports the view that homologous cell-cell contact in mammalian tissues is triggered by such lectin-receptor interaction and that the previously reported cell-surface adhesive proteins serve as a secondary force to strengthen cell adhesion. This cell model could be extremely useful for investigating the direct role of cell-surface lectin and its receptor in homologous cell adhesion in a variety of tissues under normal and pathological conditions.
Cell Mol Biol Lett 2010 Jun
PMID:Homologous liver parenchymal cell-cell adhesion mediated by an endogenous lectin and its receptor. 2033 7


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