Catabolism of Naphthalenesulfonic Acids by Pseudomonas sp. A3 and Pseudomonas sp. C22

Naphthalene and two naphthalenesulfonic acids were degraded by Pseudomonas sp. A3 and Pseudomonas sp. C22 by the same enzymes. Gentisate is a major metabolite. Catabolic activities for naphthalene, 1-naphthalenesulfonic acid, and 2-naphthalenesulfonic acid are induced by growth with naphthalene, 1-naphthalenesulfonic acid, 2-naphthalenesulfonic acid, methylnaphthalene, or salicylate. Gentisate is also an inducer in strain A3. Inhibition kinetics show that naphthalene and substituted naphthalenes are hydroxylated by the same naphthalene dioxygenase. Substrates with nondissociable substituents such as CH₃, OCH₃, Cl, or NO₂ are hydroxylated in the 7,8-position, and 4-substituted salicylates are accumulated. If CO₂H, CH₂CO₂H, or SO₃H are substituents, hydroxylation occurs with high regioselectivity in the 1,2-position. Thus, 1,2-dihydroxy-1,2-dihydronaphthalene-2-carboxylic acids are formed quantitatively from the corresponding naphthalenecarboxylic acids. Utilization of naphthalenesulfonic acids proceeds by the same regioselective 1,2-dioxygenation which labilizes the C—SO₃⁻ bond and eliminates sulfite.     

Two actin variants in developing axolotl heart

Heart development in the Mexican salamander, Ambystoma mexicanum has been studied using two-dimensional gel electrophoresis and electron microscopy. At the preheart beat stage two forms of action, α and β, are present in the heart in approximately equal quantity, however, very few definitive thin filaments can be distinguished at this stage. Once the heart beat is initiated and heart development progresses α-actin increases relative to β-actin. This increase in muscle-specific actin is coincidental with the appearance of numerous thin filaments in the myocyte.     

A Substrate for Direct Measurement of L-iduronic Acid 2-sulfate sulfatase

Commercially available sodium heparinate has been sequentially treated with methanolic 0.06M hydrogen chloride and nitrous acid. The nondegraded material was separated by gel filtration from the nonsulfated and monosulfated disaccharides produced. The latter ones, obtained in 10% yield, have been used as a substrate for the direct measurement of the enzyme L-iduronic acid 2-sulfate sulfatase present in human plasma and fibroblast homogenates. Studies of the kinetics and pH optimum of the enzyme, by use of plasma of a patient with mucolipidosis II, indicated an apparent K_m of 2.5mM and a pH optimum of 4.6-4.8. The levels of activity in normal plasma and plasma of a patient with Hunter's disease were found to be 20.4 ± 1.22 units (μmol sulfate/24 h/g protein) and 3.25 ± 0.35 units, respectively. In homogenates of cultured skin fibroblasts, the levels were 137.6 ± 10.7 units for normal controls and 6.4 ± 5.1 for patients with Hunter's disease. The plasma of two obligated heterozygotes gave intermediate levels of activity, whereas the plasma of two possible heterozygotes gave either intermediate levels or entirely normal levels of activity.     

Secretion of granule enzymes from alveolar macrophages : Regulation by intracellular Ca-buffering capacity

Rabbit alveolar macrophages exposed to the ionophore A23187 in the presence of extracellular Ca²⁺ take up about 12 nmoles of Ca²⁺/1 × 10⁶ cells. This uptake induces a slight, but significant, extracellular release of granule enzymes, β-glucuronidase and lysozyme, but not of the cytoplasmic marker, lactate dehydrogenase. If either EGTA is added to the medium or Mg²⁺ replaces Ca²⁺ no stimulation of secretion is observed. If the energy supply is decreased by treating the macrophages with mitochondrial inhibitors such as oligomycin, cyanide, or rotenone and antimycin, Ca²⁺-dependent secretion is potentiated several fold. Selective release of granule enzymes from macrophages exposed to A23187 and Ca²⁺ is also stimulated by cytochalasin B (CB).     

Antigen-binding cells in central and peripheral lymphoid tissues of the rabbit

The rosette assay was used to study antigen-binding activity by cells in lymphoid tissues of rabbits immunized with sheep red blood cells and in unimmunized controls. Percentages of rosette-forming cells (RFC) observed were compared with those of cells which secreted antibody (plaque-forming cells, PFC) and cells which both bound antigen and secreted antibody. Rosette-forming cells and PFC were shown to be two distinct reactive cell populations. Thus, in the spleen less than 1% of RFC also formed plaques. Immediately following antigen stimulation, the number of RFC in the bone marrow decreased to below detectable limits. After an initial rise, the number of RFC in the appendix declined similarly. In contrast, RFC levels in the spleen rose steadily from the time of immunization. These patterns suggest that bone marrow and appendix may function as a reservoir of antigen-binding cells which are released to other sites following antigenic stimulation. Rosette-forming cells were rarely observed in the thymus. Rosette-inhibition studies using antisera specific for bone marrow-derived cells (anti-B) and thymus-derived cells (anti-T) revealed a markedly greater proportion of T-RFC in the appendix than in the spleen.     

Circular dichroism studies of myoglobin and leghemoglobin.

The circular dichroism spectra of leghemoglobin a from the root nodules of soybean have been compared with those for sperm whale myoglobin in the fat- and near-ultraviolet and the Soret and visible regions of the spectrum. Circular dichroism spectra in the far-ultraviolet show that the leghemoglobins all have a high alpha-helix content (soybean leghemoglobin a, 55%) regardless of the nature of bound ligands and oxidation or spin state of the heme iron. The known sequence homologies with mammalian hemoglobins may therefore be reflected in conformational homologies as suggested by the x-ray studies of Vainshtein et al. ((1975) Nature (London) 254, 163-164) on lupin leghemoglobin. Removal of the heme moiety decreases helicity by only 9% for leghemoglobins, compared with 23% for myoglobin. This, the much smaller heme contribution to the near-ultraviolet circular dichroism than in myoglobin, and the greater accessibility of the heme moiety to aqueous solvent (Nicola et al. (1974), Proc. Aust. Biochem. Soc. 7, 21) suggest that the association between heme and protein is much weaker in leghemoglobins than in myoglobin. The aromatic Soret and visible circular dichroism spectra for all derivatives of leghemoglobin are opposite in sense to those for myoglobin, showing that the patterns of protein side chain contacts with the heme are different in the two classes of heme proteins. There is strong evidence that one of the two tryptophans whose identity and structural role in myoglobin is known, is present also in plant leghemoglobins, hydrogen-bonded and in a similar nonpolar environment whether heme is present or not. The above findings help to explain the remarkably high oxygen affinity and some other ligand-binding properties of leghemoglobins which differ from those of myoglobin.     

Relationships between platelet and plasma monoamine oxidase,plasma dopamine-B-hydroxylase,and urinary 3-methoxy-4-hydroxy phenylglycol

The activity of dopamine-B-hydroxylase in blood has recently been demonstrated to be under genetic control and to correlate closely with urinary catecholamine excretion. The results of the present study did not demonstrate any relationship between a major catecholamine metabolite in urine, 3-methoxy-4-hydroxy phenylglycol, and dopamine-B-hydroxylase activity in plasma, monoamine oxidase activity in platelets, or monoamine oxidase activity in plasma. Differences in the origin of urinary catecholamines and urinary 3-methoxy-4-hydroxy phenyglycol may be responsible for these divergent results.     

Cu(II) ion interaction with teicoplanin-vancomycin’s analog

Teicoplanin, a member of the “last chance” antibiotic family has a similar structure and the same mechanism of action as parent drug vancomycin, which is proved to be an effective binder of Cu(II) ions. However, the potentiometric and spectroscopic studies (UV-visible, CD, NMR) have shown that the modification of the N-terminal structure of the peptide backbone in teicoplanin affects considerably the binding ability towards Cu(II) ions. While vancomycin forms almost instantly the stable 3 N complex species involving the N-terminal and two amide nitrogen donors, in case of teicoplanin only two nitrogen donors derived from the N-terminal amino group and adjacent peptide bond are coordinated to Cu(II) ion within the whole pH range studied. The major factor influencing the binding mode is most likely the structure of the N-terminus of the peptide unit in the antibiotic ligand.     

Immunologic reactivity to incompatible blood group substances of the ABO system in scleroderma.

The immunization with incompatible blood groups substances of the ABO system yielded distinct increases in the isohemagglutinin titers and their scores in 16 patients suffering from systemic sclerosis (scleroderma) and in 16 controls. The difference between these two groups was not statistically significant, which suggests an intact humoral immunological reactivity of these antigens. However, investigations with further antigens would be necessary to judge the immunological factors supposed to be involved in the pathogenesis of systemic sclerosis. The method may be recommended for testing the humoral immunological response in similar problems.