Isoform, kinetic and immunochemical characterization of rodent liver alpha-L-fucosidases

alpha-L-Fucosidase from hamster and six inbred mouse strains contains two to three unique basic isoelectric forms (above pI 7.0) in addition to the usual acidic and neutral isoforms from pI 4-7. Rat liver alpha-L-fucosidase contains multiple isoforms between pI values of 4.0 and 7.3 whereas guinea pig liver alpha-L-fucosidase exhibits a single broad isoform at pI 5.3. 2. All the alpha-L-fucosidases have similar KM values (0.05-0.12 mM) for 4-methylumbelliferyl-alpha-L-fucopyranoside but pH-activity curves which are significantly different in optima and per cent of optimal activity in the acid region. 3. Double-antibody immunoprecipitation experiments indicate that rodent liver alpha-L-fucosidases crossreact to varying extents with polyclonal antibody against human liver alpha-L-fucosidase. 4. Hamster, guinea pig and mouse liver alpha-L-fucosidases exhibit significantly less binding than human and rat liver fucosidases to the agarose-epsilon-aminocaproylfucosamine affinity resin.     

A comparison between biochemical tests and the 'CAMP' reaction for identification of Aeromonas spp.

Aeromonas bacteria (110 strains) from a variety of clinical, food and environmental sources, were identified using routine biochemical tests. Concurrently they were tested aerobically and anaerobically for their ability to perform synergistic haemolysis with Staphylococcus aureus (the 'CAMP' reaction). Results did not support a reported observation that the 'CAMP' reaction can he used to facilitate speciation of Aeromonas bacteria.     

Sequence and relatedness in other bacteria of the Pseudomonas aeruginosa oprP gene coding for the phosphate-specific porin P

The oprP gene encoding the Pseudomonas aeruginosa phosphate-specific outer membrane porin protein OprP was sequenced. Comparison of the derived amino acid sequence with the known sequences of other bacterial porins demonstrated that OprP could be no better aligned to these porin sequences than it could to the periplasmic phosphate-binding protein PhoS of Escherichia coli. Southern hybridization and restriction mapping of the oprP gene in 37 clinical isolates and the 17 serotype strains of P. aeruginosa revealed that restriction sites in the vicinity of the oprP gene were highly conserved. Several species from the Pseudomonas fluorescens rRNA homology group contained DNA that hybridized to an oprP gene probe.     

Neurofilament Proteins Are Distributed in a Diminishing Proximodistal Gradient Along Rat Sciatic Nerve

Neurofilament (NF) proteins are distributed in a diminishing proximodistal gradient along rat sciatic nerve when compared with total noncollagen or other proteins in nerve. About a twofold decline of NF proteins can be detected by quantitating nerve proteins that have been separated by gel electrophoresis. A similar decrease of immunoreactivity to each NF subunit is seen in distal nerve segments when noncollagen nerve proteins are immunoblotted. Parallel decreases occur in all three NF proteins, thereby maintaining neurofilament subunit stoichiometry along the neuraxis. The same NF gradient can be detected when the NF contents in nerve branches to the gluteus and gastrocnemius muscles are compared with each other and with those in nerve segments taken from the same proximodistal levels of the parent sciatic nerve. The gradient of NF proteins increases during postnatal development and is readily detected by postnatal day 16. During the same period of development, the heavy NF subunit appears for the first time and is rapidly incorporated throughout the sciatic nerve. Hence, the NF gradient becomes manifest during the development and maturation of the adult form of the axonal cytoskeleton. The basis for the proximodistal gradient of NF proteins in peripheral nerve is presently unknown. The extent of the gradient cannot be accounted for on the basis of diminishing numbers of nerve fibers or increasing amounts of other nerve proteins, e.g., collagen, in distal nerve. An alternative interpretation is that the gradient reflects a low level of NF protein turnover during axonal transport.     

The effect of water stress on the vacuole-extravacuole compartmentation of proline in potato cell suspension cultures

Solute compartmentation in cells is an important component of metabolic regulation. There is only little information on how stress treatment of cells effects this component. Therefore, the effect of water stress [10% (w/v) PEG 6000] on the vacuolar-extravacuolar proline compartmentation was studied in a cell suspension culture of Svlanum tuberosum L, cv, HH258, In non-stressed cells 34% of the total cellular proline was located in the vacuole. After 20 h of water stress the proline pool of the cells was increased 4-6 fold and only t6% of it was found in the vacuole. A negative correlation between the total cellular proline content and its percentage in the vacuole was observed, irrespective of the culture method (stress or non-stress culture). The stress-induced changes in proline compartmentation are discussed.     

An antibody-induced enhancement of the transducin-stimulated cyclic GMP phosphodiesterase activity

In this work we have characterized the ability of a carboxyl peptide-specific antibody (AS/7), raised against the alpha subunit of transducin (alpha T), to potentiate the stimulation of the cyclic GMP phosphodiesterase (PDE) by transducin. The complexation of the purified guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S)-bound form of alpha T (alpha T.GTP gamma S) with AS/7 results in a 2-5-fold enhancement in the total levels of cyclic GMP hydrolysis measured after 1 min. This potentiation by AS/7 cannot be attributed simply to an increase in the apparent affinity of alpha T.GTP gamma S for the effector enzyme, nor to an increased affinity of the enzyme for the substrate cyclic GMP. The AS/7-induced potentiation is specific for alpha T.GTP gamma S-PDE interactions; this antibody has no effect on the activity of the trypsin-activated PDE nor on the ability of the GDP-bound form of alpha T to inhibit the trypsin-activated enzyme (Kroll, S., Phillips, W. J., and Cerione, R. A. (1989) J. Biol. Chem. 264, 4490-4497). Phosphatidylcholine vesicles also will enhance the alpha T.GTP gamma S-stimulated PDE activity (1.5-2-fold) relative to that measured in the absence of a lipid milieu. However, the potentiations of alpha T-stimulated cyclic GMP hydrolysis elicited by AS/7 and lipids represent separate events. Titration profiles describing the AS/7-induced potentiation, as a function of the amount of antibody added to the assay mixtures, indicate that maximal activity occurs when there is one molecule of AS/7 per two molecules of alpha T.GTP gamma S; the AS/7-induced potentiation is lost when AS/7 much greater than alpha T. GTP gamma S, i.e. conditions which favor the formation of monovalent AS/7-alpha T.GTP gamma S complexes. When the AS/7 is papain-treated to yield monovalent antibody molecules, complexation between these monovalent antibodies and alpha T still occurs (as reflected by the ability of these antibodies to block rhodopsin-alpha T coupling); however, the potentiation of the alpha T.GTP gamma S-stimulated PDE activity is lost. Taken together, these results suggest that the AS/7-induced potentiation of alpha T-stimulated activity is dependent on the bivalent nature of the antibody, and maximal stimulation of PDE activity is achieved by the interactions of two activated-alpha T molecules with a single molecule of PDE.