Colloid and crystal formation in parotid saliva of cystic fibrosis patients and non-cystic fibrosis subjects. II. Electron microscopy and electrophoresis.

Centrifuged pellets of turbid parotid saliva from cystic fibrosis (CF) patients and non-CF subjects, obtained from saliva kept at 2 degrees for 10 min, had the electron microscope appearance of amorphous, round particles, and were thought to be colloidal aggregates of organic material. Drops of turbid saliva, from samples incubated for 2 hr at 2 degrees or 37 degrees, additionally contained discrete, electron-dense crystals having well defined angular morphology: usually cubic, retangular, or approximately hexagonal. The inhibitors, urea, guanidine hydrochloride, and EDTA, resulted in no crystals being observed. Selected area electron diffraction from individual crystals showed predominantly hexagonal, rectangular patterns could be indexed as coming from hydroxyapitite. A transition from the hexagonal to the rectangular pattern and back to the hexagonal pattern could be obtained from individual crystals tilted in the electron microscope. The square diffraction pattern may be from octa-calcium or brushite. Polyacrylamide gel disc electrophoresis of the parotid saliva indicated that the sparingly soluble proteins in the 2 degree and 37 degree pellets comprised proline-rich proteins and a calcium-precipitable, trichloroacetic acid (TCA)-precipitable phosphoprotein, which fluoresced with amido schwarz and Coomassie brilliant blue G250

The dissociation of the fluid and particle phase in the forestomach as a physiological characteristic of large grazing ruminants: an evaluation of available, comparable ruminant passage data

Whether differences in digestive physiology exist between different ruminant feeding types has been an ongoing debate. In this regard, potential differences in ingesta retention have been understood to be of particular importance. We analyzed a data pool in which only mean retention time (MRT) data for the ruminoreticulum (RR) were collated that were obtained using comparable techniques with either chromium or cobalt EDTA as a fluid marker and/or with chromium-mordanted fiber of less than 2 mm in size as a particle marker. Data were compared using one averaged value per species. In general, the paucity of species in such a collection is striking and does not allow—in contrast to earlier statements—any final conclusions regarding the influence of body weight (BW) or feeding type on ruminant MRTs. In particular, there was no significant correlation between MRTparticlesRR or MRTfluidRR and BW, neither in the interspecific nor in the intraspecific comparisons, and no difference between the feeding types. The trend that indicates longer MRTparticlesRR in grazers is based on too few species to be conclusive. Small browsers seemed to have shorter MRTfluidRR than similar-sized grazers. In contrast, there was a trend for large grazers to have shorter MRTfluidRR than large browsers. In direct pair-wise comparisons between cattle and the browsers giraffe, moose, and okapi, the latter difference was significant. Cattle also had the highest relative RR fluid outflow rates among the species investigated. This is in accord with the observation that grazers have larger omasa, a major function of which is water-reabsorption distal to the RR. Grazers seem to have longer MRTparticlesRR per unit MRTfluidRR, and cattle are particular outliers in this respect. It is hypothesized that potentially shorter MRTfluidRR in large grazers and higher relative outflow rates are linked to a higher saliva production and a lesser viscosity of both saliva and RR fluids. A constant supply of a fluid phase of low viscosity is proposed to be the prerogative for the physical mechanisms of flotation and sedimentation that result in the stratification of RR contents and its selective particle retention typical for large grazing species

Osmoregulatory capacity of the Cladocera.

Within the order Cladocera are found almost all varieties of osmotic regulation, which make it possible for them to live in waters of a wide range of salt concentrations. Many Cladocera are very powerful osmoregulators and are comparable to the teleosts and decapod crustaceans in their abilities. The variety of osmoregulatory capacities within the cladocerans are illustrated and discussed. The function of mitochondrion-rich ion transporting cells found in nuchal glands or on epipodites are diseussed and the physiological mechanisms involved in osmoregulation are compared with similar mechanisms in other crustaceans and in teleosts. Data is provided on osinotic regulation in eggs and embryos in open and elosed brood chambers. Other topics include the occurrence of physiological races in some species, recent changes in osmoregulatory abilities following man-induced changes in salinity, the effects of temperature on osmoregulation and the effects of pH