A mutation in the TRPC6 cation channel causes familial focal segmental glomerulosclerosis

Focal and segmental glomerulosclerosis (FSGS) is a kidney disorder of unknown etiology, and up to 20% of patients on dialysis have been diagnosed with it. Here we show that a large family with hereditary FSGS carries a missense mutation in the TRPC6 gene on chromosome 11q, encoding the ion-channel protein transient receptor potential cation channel 6 (TRPC6). The proline-to-glutamine substitution at position 112, which occurs in a highly conserved region of the protein, enhances TRPC6-mediated calcium signals in response to agonists such as angiotensin II and appears to alter the intracellular distribution of TRPC6 protein. Previous work has emphasized the importance of cytoskeletal and structural proteins in proteinuric kidney diseases. Our findings suggest an alternative mechanism for the pathogenesis of glomerular disease.     

Expression and function of junctional adhesion molecule-C in myelinated peripheral nerves

JAM-C is an adhesion molecule that is expressed on cells within the vascular compartment and epithelial cells and, to date, has been largely studied in the context of inflammatory events. Using immunolabeling procedures in conjunction with confocal and electron microscopy, we show here that JAM-C is also expressed in peripheral nerves and that this expression is localized to Schwann cells at junctions between adjoining myelin end loops. Sciatic nerves from JAM-C-deficient [having the JAM-C gene knocked out (KO)] mice exhibited loss of integrity of the myelin sheath and defective nerve conduction as indicated by morphological and electrophysiological studies, respectively. In addition, behavioral tests showed motor abnormalities in the KO animals. JAM-C was also expressed in human sural nerves with an expression profile similar to that seen in mice. These results demonstrate that JAM-C is a component of the autotypic junctional attachments of Schwann cells and plays an important role in maintaining the integrity and function of myelinated peripheral nerves.     

Elucidation of the effect of formaldehyde and lipids on frozen stored cod collagen by FT-Raman spectroscopy and differential scanning calorimetry

The effect of frozen storage (-10 and -30 degrees C), formaldehyde, and fish oil on collagen, isolated from cod muscle, was investigated. Salt- and acid-soluble collagen fractions as well as insoluble collagen indicated changes in solubility on frozen storage. Differential scanning calorimetry (DSC) showed a highly cooperative transition at 28.2 degrees C for isolated collagen. Changes in the thermodynamic properties of collagen were observed on frozen storage at -10 degrees C compared with the control at -30 degrees C because of changes in structure. In the presence of formaldehyde, there were no changes in the DSC collagen transition; however, in the presence of fish oil there was an increase in enthalpy and an extra peak was observed at 44.6 degrees C, indicating collagen-fish oil interaction. Structural changes resulted in a decrease in the solubility of collagen in salt and acid solution. FT-Raman spectra obtained for collagen at -10 degrees C and -30 degrees C confirmed the alteration of the conformation of collagen not only at -10 degrees C but also in the presence of formaldehyde and fish oil.     

Forage and migration habitat of loggerhead (Caretta caretta) and olive ridley (Lepidochelys olivacea) sea turtles in the central North Pacific Ocean

Satellite telemetry from 26 loggerhead (Caretta caretta) and 10 olive ridley (Lepidochelys olivacea) sea turtles captured and released from pelagic longline fishing gear provided information on the turtles’ position and movement in the central North Pacific. These data together with environmental data from satellite remote sensing are used to describe the oceanic habitat used by these turtles. The results indicate that loggerheads travel westward, move seasonally north and south primarily through the region 28–40°N, and occupy sea surface temperatures (SST) of 15–25°C. Their dive depth distribution indicated that they spend 40% of their time at the surface and 90% of their time at depths <40 m. Loggerheads are found in association with fronts, eddies, and geostrophic currents. Specifically, the Transition Zone Chlorophyll Front (TZCF) and the southern edge of the Kuroshio Extension Current (KEC) appear to be important forage and migration habitats for loggerheads. In contrast, olive ridleys were found primarily south of loggerhead habitat in the region 8–31°N latitude, occupying warmer water with SSTs of 23–28°C. They have a deeper dive pattern than loggerheads, spending only 20% of their time at the surface and 60% shallower than 40 m. However, the three olive ridleys identified from genetics to be of western Pacific origin spent some time associated with major ocean currents, specifically the southern edge of the KEC, the North Equatorial Current (NEC), and the Equatorial Counter Current (ECC). These habitats were not used by any olive ridleys of eastern Pacific origin suggesting that olive ridleys from different populations may occupy different oceanic habitats.     

Modeling organic and inorganic acidity in two Nova Scotia rivers

A watershed acidification model is modified to include organic acids and applied to the colored Moose Pit Brook and Mersey River in Nova Scotia. Comparison with 1983–1985 data confirmed the capability of the model to explain the different levels of organic and inorganic acidity exhibited in these two rivers. Based on the charge balance approach and a triprotic organic acid model, the charge density was found to be about 4 μeq organic anions per mg C of dissolved organic C for these two rivers.