Immunochemical properties of D-amino-acid oxidase

Antiserum against homogeneous hog kidney D-amino-acid oxidase (D-amino-acid: oxygen oxidoreductase (deaminating), EC 1.4.3.3) was elicited in rabbits, and monospecific antibodies were prepared by affinity chromatography. The antibodies inhibited up to 90% of hog D-amino-acid oxidase activity, and 100% of the enzyme could be immunoprecipitated. The antibodies inhibited both holoenzyme and reconstituted apoprotein to a similar degree, indicating that they did not interfere with the FAD-binding site of the protein. The antibodies inhibited D-amino-acid oxidase activity from other mammalian species to a similar degree, while the enzyme activities from birds, amphibians, fishes and yeast were inhibited and immunoprecipitated to lower extents. In immunoblotting experiments, after SDS-polyacrylamide gel electrophoresis, the antibodies recognized a single band of about 40 kDa in all the species analyzed, and the entity of the signal was inversely related to the phylogenetic distance from mammals. The antibodies did not inhibit D-alanine dehydrogenase activity from Escherichia coli, but gave positive bands in immunoblotting.     

Physicochemical characterization of alpha-crystallins from bovine lenses: hydrodynamic and conformational properties

A detailed investigation of hydrodynamic and conformational behavior has been made of the HM-crystallin and -crystallins of bovine lens. Results from this study indicated that HM (high-molecular-weight -crystallin) and (low-molecular-weight -crystallin) possess considerable size and charge heterogeneities in their native structures and subunit polypeptides, respectively. Sedimentation velocity showed a heterogeneous polydisperse system of HM with an average sedimentation coefficient of about 50 S and a more homogeneous system of -crystallin of 20 S. Viscosity and circular dichroism studies pointed to a compact and globular shape of dominant -sheet conformation for -crystallin, yet a highly asymmetrical and aggregated form for HM. The conformational stability of -crystallin was investigated in the presence of various denaturants. The evidence presented shows that hydrogen bonding is the main force in maintaining the quaternary structure of compact native -crystallin. Conformational flexibility of -crystallin demonstrated in the equilibrium unfolding study indicated a multistep transition that made the extraction of thermodynamic data from the heat denaturation study difficult. Temperature perturbation on -crystallin suggested the possible involvement of hydrophobic interaction in the aggregation process, leading to the formation of HM from -crystallin. The comparison of conformational properties between HM and -crystallin strongly indicated that HM is a denatured form of -crystallin.     

Immunochemical properties ofVibrio cholerae LPS

Immunochemical analysis of LPS isolated fromVibrio cholerae O1 and non O1 showed that this macromolecular complex shares common antigenic epitopes in the sugar moiety. The epitopes can be detected after mild alkaline hydrolysis of LPSin vitro. Membrane-associating activity of both O1 and non O1 LPS did not indicate any differences of the species.     

Altered chaperone-like activity of alpha-crystallins promotes cataractogenesis

Despite the enormous number of studies demonstrating changes in the chaperone-like activity of α-crystallins in vitro, little is known about how these changes influence life-long lens transparency in vivo. Using the γB-crystallin I4F mutant protein as a target for αA-crystallins, we examined how cataract phenotypes are modulated by interactions between α-crystallins with altered chaperone-like activities and γB-I4F proteins in vivo. Double heterozygous α-crystallin knock-out αA(+/-) αB(+/-) mice with a decreased amount of α-crystallins were used to simulate reduced total α-crystallin chaperone-like activity in vivo. We found that triple heterozygous αA(+/-) αB(+/-) γB(I4F/+) mice developed more severe whole cataracts than heterozygous γB(I4F/+) mice. Thus, total chaperone-like activity of α-crystallins is important for maintaining lens transparency. We further tested whether mutant αA-crystallin Y118D proteins with increased chaperone-like activity influenced the whole cataract caused by the γB-I4F mutation. Unexpectedly, compound αA(Y118D/+) γB(I4F/+) mutant lenses displayed severe nuclear cataracts, whereas the lens cortex remained unaffected. Thus, the synergistic effect of αA-Y118D and γB-I4F mutant proteins is detrimental to the transparency only in the lens core. α-Crystallins with different chaperone-like activities are likely required in the lens cortex and nucleus for maintaining transparency.     

Electrical properties of vertebrate oocyte membranes

The electrical properties of vertebrate oocyte and egg cell membranes are reviewed. Ion channels of these oocytes generate transcellular currents and action potentials as well as responses to neurotransmitters. Electrical properties change during meiotic maturation and fertilization. Available information about the electrical properties of sperm is also discussed.     

Immunochemical properties of phosphatidyl cholesterol and its homologue

1,2-Dipalmitoyl-rac-glycerol-3-phosphoryl-3'-cholesterol (PCH) and 1,2-dipalmitoyl-rac-glycerol-3-phosphoryl-20'-(3-hydroxy norpregn-5-ene) (PET) were combined with poly-L-lysine to form a PCH-poly-L-lysine complex and a PET-poly-L-lysine complex, respectively. These complexes were subcutaneously injected into rabbit foot pad with Freund's complete adjuvant. PCH antiserum showed specificites against the phosphatidyl group, the cholesterol moiety and the side chain of cholesterol. PET antiserum contained the specific antibodies against the phosphatidyl group, the cholesterol moiety and the OH-group at the C3 position of the cholesterol molecule.     

Immunochemical properties of immunoglobulin G conjugated with dextran

Antigen-binding activity and effector functions of immunoglobulin G from horse and rabbit sera have been investigated, using hemagglutination, kinetic immune lysis, immune lysis in microplates and rosette-forming test with peritoneal mononuclear cells of mice, after their conjugation with dextran, MW 35-50 kD. The formation of conjugates of two types has been demonstrated: protein-dextran and protein-dextran-protein. It has been revealed that protein-dextran-protein conjugates have high specific antigen-binding activity, as compared to native IgG from rabbit sera specific for SRBC, while interactions with the complement system and Fc receptors is depressed.     

Immunochemical properties of naturally occurring antiglobulin factors-homoreactants]

The naturally-occurring antiglobulin factors to the pepsin fragments of the homologous IgG (homoreactants or agglutinins) present in the human and rabbit sera and gamma-globulin preparations, behaved in Sephadex G-200 gelchromatography as proteins with a molecular weight of approximately 250,000 daltons. It was shown that the human pepsin homoreactant failed to penetrate through the placenta. Since the pepsin homoreactant was absorbed specifically by the insolubilized antibodies against the Fc portion of the IgG molecule, the data obtained could indicate that the homoreactant activity was associated with the IgG molecules of the unusual structure.     

Kinetic properties of primitive vertebrate carbonic anhydrases

• 1.1. Carbonic anhydrases from the red cells, ocular secretory tissues, and rectal gland of species of Myxine, elasmobranchii, and Teleostii, were examined using rates of CO₂ hydration. The enzyme is absent from corneal endothelium and lens of elasmobranchs and salt water teleosts, but present in fresh water fish.
• 2.2. The red cell carbonic anhydrase of the representative elasmobranch, Squalus acanthias, is a single enzyme of relatively low activity, K_cat = 2 × 10⁴ sec⁻¹ at 1°C. The ciliary folds and rectal gland of S. acanthias contain carbonic anhydrases with turnover numbers five times higher than the red cell enzyme.
• 3.3. Both red cell and secretory enzymes of S. acanthias are susceptible to inhibition by sulfonamides within a 10-fold range of mammalian secretory carbonic anhydrases. In general, they are moderately sensitive to anion inhibition; a notable exception is enzyme from rectal gland which is insensitive to halion inhibition.
• 4.4. In teleosts, both red cell and secretory carbonic anhydrases have a high turnover number, and are susceptible to sulfonamide inhibition. In red cells there appear isozyme(s) of lower activity, in considerable concentration.
• 5.5. Taken with earlier ion transport work in S. acanthias, the basic vertebrate pattern of aqueous humor formation, both chemically and physiologically, appears to be established in this “primitive” species.
• 6.6. The finding of at least three different types of carbonic anhydrases in S. acanhias suggests that separate loci for the enzyme have existed throughout most of vertebrate evolution.

     

Neuromodulation of vertebrate motor neuron membrane properties

The short-term function of motor neurons is to integrate synaptic inputs converging onto the somato-dendritic membrane and to transform the net synaptic drive into spike trains. A set of voltage-gated ion channels determines the electro-responsiveness and thereby the motor neuron's input-output function. In addition, several of the decisive ion channels are transmitter controlled, which results in a flexible control of the input-output relationship.     

Immunochemical properties of a protective cross-reacting antigen of meningococci

The study of protective cross-reacting antigenic preparations isolated from meningococci of groups A and C in the blot immunoassay has shown the presence of a group of proteins with a molecular weight ranging from 23 to 31 KD and common for 8 tested serological groups of meningococci, gonococci and 4 nonpathogenic Neisseria species. The possible role of these structures as common Neisseria antigen in the formation of natural resistance to meningococcal infection is discussed.