FAB CID-MS/MS characterization of tetrasaccharide tri- and tetrasulfate derived from the antigenic determinant recognized by the anti-chondroitin sulfate monoclonal antibody MO-225

The fast atom bombardment (FAB) collision induced dissociation (CID)-mass spectrometry/mass spectrometry (MS/MS) technique was successfully applied to characterize and identify the structures of the immunoreactive trisulfated and tetrasulfated tetrasaccharides that were obtained from the chondroitin sulfate in a shark fin using a treatment with chondroitinase ABC.Abbreviations FABMS fast atom bombardment mass spectrometry - CID collision induced dissociation - MS/MS mass spectrometry/mass spectrometry - UA2S-GalNAc6S 2-acetamido-2-deoxy-3-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-galactose - UA-GalNAc4S 2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-4-O-sulfo-d-galactose - UA-GalNAcDiS 2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-4,6-di-O-sulfo-d-galactose     

Ecomorphological correlates in ten species of subtropical seagrass fishes: diet and microhabitat utilization

Synopsis Ecomorphological correlates were sought among ten species of distantly related subtropical seagrass fishes. Morphometric data associated with feeding and microhabitat utilization were compared by principal components analysis, cluster analysis, and canonical correspondence analysis to dietary data. Morphology was generally a poor predictor of diet except for a group of mid-water planktotrophic filter feeders. Separation of the species along morphological axes appears to be related more to microhabitat utilization resulting in three major groups: (1) a group of planktotrophic, mid-water fishes specialized for cruising and seeking out evasive prey characterized by a compressed fusiform body, forked caudal fin, long, closely spaced gill rakers, short to intermediate! length pectoral fin, pointed pectoral fin, large lateral eye, short head, and a terminal or subterminal mouth; (2) slow swimming, less maneuverable epibenthic fishes that pick or suck their prey off the substrate. They are united by more rounded caudal and pectoral fins, and short or no gill rakers; and (3) a group of more mobile and maneuverable epibenthic foragers characterized by a more compressed, sub-gibbose body, long, pointed pectoral fins, forked caudal fins, large lateral eyes, subterminal mouth, and greater jaw protrusibility. Cases of convergence in trophic and microhabitat utilization characters were apparent in some of the groups.     

High-level 2H/13C/15N labeling of proteins for NMR studies

Summary The protein human carbonic anhydrase II (HCA II) has been isotopically labeled with ²H, ¹³C and ¹⁵N for high-resolution NMR assignment studies and pulse sequence development. To increase the sensitivity of several key ¹H/¹³C/¹⁵N triple-resonance correlation experiments, ²H has been incorporated into HCA II in order to decrease the rates of ¹³C and ¹H_N T₂ relaxation. NMR quantities of protein with essentially complete aliphatic ²H incorporation have been obtained by growth of E. coli in defined media containing D₂O, [1,2-¹³C₂, 99%] sodium acetate, and [¹⁵N, 99%] ammonium chloride. Complete aliphatic deuterium enrichment is optimal for ¹³C and ¹⁵N backbone NMR assignment studies, since the ¹³C and ¹H_N T₂ relaxation times and, therefore, sensitivity are maximized. In addition, complete aliphatic deuteration increases both resolution and sensitivity by eliminating the differential ²H isotopic shift observed for partially deuterated CH_nD_m moieties.     

Yeast hexokinase mutants.

Using yeast mutants, it is shown that growth on glucose occurs even in the absence of both hexokinase A and hexokinase B; fructose growth requires at least one of these two enzymes. Expression of hexokinase A and of glucokinase seem to be regulated.     

An Automated Technique for the Radiographic Determination of Bone Age

We have developed an automated procedure for determining bone-age in the monkey, Macaca fascicularis. The status of epiphysial junctions and sesamoids were determined from radiographs. Epiphyses were scored as either open or closed, and sesamoids were scored as either present or absent. Bone-age was calculated by a computer program that stored and used a data base of probabilities for epiphysial closure and sesamoid appearance. The simplicity of scoring, combined with the speed and accuracy of the calculations, make this technique potentially adaptable for use in a variety of primate species.     

Virus-like particles in the brown algaStreblonema

Summary Ultrastructural examination ofStreblonema sp. revealed icosahedral virus-like particles (135–150 nm) throughout the cytoplasm of vegetative cells. The densely packed particles consist of an osmiophilic coat around a fibrillar core. Most cytoplasmic organelles are excluded from the regions where the particles are extremely abundant, but no degeneration of plastids, mitochondria or dictyosomes is evident. The virogenic stroma contains many ribosomes and fibers possibly representing DNA strands remaining from the lysed nucleus. No decrease in vigor seemed to be associated with the presence of the particles.     

Surgical Management of Epilepsy

Therapy with anticonvulsant drugs reduces the frequency and severity of seizures in many but not all epileptic patients. Unfortunately, in a significant number control remains poor even when maximal doses of multiple anticonvulsant drugs are given. Some of these patients are candidates for surgical treatment of epilepsy. The operative management of convulsive disorders is a well-established technique and is available in some centers. In selected cases, such operations are both safe and effective, with good longterm improvement or complete control in 76 percent of patients. We have summarized the 24-year experience with surgical operation for epilepsy at the University of Washington Medical Center.     

Effect of intracellular potassium upon the electrogenic pump of frog retinal pigment epithelium

Summary We have studied the hyperpolarizing, electrogenic pump located on the apical membrane of the retinal pigment epithelium (RPE) in anin vitro preparation of bullfrog RPE-choroid. Changes in RPE [K⁺] _i alter the current produced by this pump. Increasing [K⁺] _o in the solution perfusing thebasal membrane increases RPE [K⁺] _i (measured with a K⁺-specific microelectrode), and also depolarizes theapical membrane. This depolarization is due to a decrease in electrogenic pump current flowing across the apical membrane resistance, since it is abolished when the pump is inhibited by apical ouabain, by cooling the tissue, or by 0mm [K⁺] _o outside the apical membrane. Removal of Cl^– from the solution perfusing the basal membrane abolishes the K⁺-evoked apical depolarization by preventing the entry of K⁺ (as KCl) into the cell. We conclude that the increase in [K⁺] _i causes the decrease in pump current. This result is consistent with the finding that [K⁺] _i is a competitive inhibitor of the Na⁺–K⁺ pump in red blood cells.It is possible that the light-evoked changes in [K⁺] _o in the distal retina could alter RPE [K⁺] _i , and thus could affect the pump from both sides of the apical membrane. Any change in pump current is likely to influence retinal function, since this pump helps to determine the composition of the photoreceptor extracellular space.