Definition by CB12 monoclonal antibody of a differentiation marker specific for human monocytes and their bone marrow precursors

The CB12 monoclonal antibody, which reacts with a molecule expressed on monocytes, was characterized using human embryonic material as immunizer. Analysis of the monoclonal antibody at the phenotypic, molecular, and functional levels indicates that its reactivity is restricted to circulating monocytes and their precursors in the bone marrow, whereas it is undetectable on tissue macrophages. CB12 displays a pattern of reactivity compatible with that of a marker of monocyte differentiation. Preliminary data indicate a possible receptor role for the CB12 molecule.     

CD38 molecule: structural and biochemical analysis on human T lymphocytes, thymocytes, and plasma cells.

The structure of the CD38 molecule has been evaluated by one- and two-dimensional gel analysis and by enzymatic digestions. The source of the Ag was mainly membrane preparations obtained from MLC cells, from normal thymocytes, and from the plasmocytoma line LP-1. Membranes were solubilized in NP-40 and the extracts fractionated by immunoaffinity chromatography [using a specific anti-CD38 antibody (A10 mAb) covalently linked to Sepharose protein A]. The purified Ag migrated as a single chain of Mr = 45,000 not associated with beta 2-microglobulin. Two-dimensional IEF gel electrophoresis revealed five spots (isoelectric point (pI) range: 6.5 to 6.9). After neuraminidase treatment, the mobility of the five polypeptides shifted to a more basic pI. Endoglycosidase-H treatment reduced the Mr of CD38 by 20%, revealing a broader band centered at Mr = 36,000. Treatment of CD38 molecule with V8 Staphylococcus aureus protease yielded a single dominant band at Mr = 38,000 which was still reactive with A10 mAb. The CD38 molecular was trypsin-resistant in both denatured or native conditions. These results clearly show the glycoprotein nature of CD38 molecule, which includes 2 to 4 N-linked oligosaccharide chains containing sialic acid residues. Furthermore, the present data indicate that the CD38 molecule does not display an apparent biochemical polymorphism among the different CD38+ cells or lines.     

Prevention of murine cryoglobulinemia and associated pathology by monoclonal anti-idiotypic antibody

A murine IgG3 mAb, clone 6-19, derived from non-manipulated autoimmune MRL/MpJ-lpr/lpr mice is a rheumatoid factor specific for IgG2a and is able to generate cryoglobulins via nonspecific IgG3 Fc-Fc interaction. Intraperitoneal passive transfer of ascites containing the 6-19 mAb into BALB/c mice induces, within 18 h, remarkable pathology characterized by skin vasculitis and acute glomerulonephritis associated with cryoglobulinemia. In order to evaluate the possibility of modulating the development of tissue lesions by an anti-Id antibody, we have raised an IgG2b anti-Id mAb specific to the 6-19 mAb. The cryoprecipitation of 6-19 mAb was completely inhibited in the presence of excess amounts of anti-Id mAb in vitro. In vivo, pretreatment of BALB/c mice with anti-6-19 anti-Id mAb inhibited development of skin vasculitis and glomerulonephritis induced by the 6-19 mAb. The cryoglobulin formation was markedly diminished due to enhanced elimination of the 6-19 mAb from the circulation. In contrast, pretreatment with an IgM anti-IgG3 rheumatoid factor mAb neither protected nor aggravated the development of tissue lesions. These results suggest possible implications in the anti-Id treatment of similar vascular diseases in man.     

NMR structural characterization of the reaction product between d(GpG) and the octahedral antitumor complex trans-RuCl2(DMSO)4.

The reaction between the antitumor octahedral complex trans-RuCl2(DMSO)4 and d(GpG) leads to the formation of a stable compound characterized by a covalent bifunctional coordination of the bases to the metal center. The structure of the compound has been fully characterized by NMR and molecular modeling studies, showing the presence of two N7-coordinated guanine moieties in a head to head conformation, two dimethyl sulfoxide molecules, and one halogen atom in the coordination sphere of the ruthenium. The glycosidic chi angles are essentially in the anti range, the sugar puckering of the 5'G is 3'-endo (100% N), whereas that of the 3'G is more flexible but mainly in 2'-endo conformation (85% S), the two bases are strongly destacked. The compound shows structural features which are surprisingly similar to those exhibited by the corresponding cisplatin complex, indicating that such a way of interaction with DNA is not exclusive to Pt or to metals with square planar coordination geometries.     

Bioleaching of manganese (IV) oxide and application to its recovery from ores

Summary Bioleaching of manganese (IV) oxide with Thiobacillus thiooxidans has been studied in media with and without sulfur, ferrous sulfide and ferrous sulfate. The knowledge of the role played by the bacteria and the reducing substances suggest that the leaching of manganese (IV) ores through the use of thiobacteria is only justified when suitable amounts of sulfur or metal sulfides are present.     

Action of Thiobacillus thiooxidans on Sulphur in the Presence of a Surfactant Agent and its Application in the Indirect Dissolution of Phosphorus

The addition of a surfactant agent (Tween 80) to a medium containing sulphur and a culture of Thiobacillus thiooxidans increased the attachment of bacteria to sulphur, the rate of sulphur oxidation and sulphuric acid production. This acid was used to dissolve phosphorus from calcium phosphate. The yield was higher than reported for other microorganisms although dissolution was not increased significantly by Tween addition.     

X-ray structure analysis of 3,11,17-trioxoandrostane-5 alpha-carbonitrile and of 17 alpha-ethoxycarbonyloxy-3-oxoandrost-4-ene-17-carbonitrile.

The crystal and molecular structures of the title compounds were determined by x-ray diffractometric analysis. Torsion angles and puckering parameters are reported for both compounds. In 1 the 5 alpha-cyano group influences the A-ring conformation. The carbonate ester 3 crystallizes in the monoclinic P2(1) space group with two molecules (I and II) in the asymmetric unit. The D-ring conformation is to some extent different between I and II.     

Actin organization and fibrin-clot retractile activity of cultured mouse fibroblasts

Summary It is known that human and animal fibroblasts are able to induce the retraction of a fibrin clot. In the present study the correlation between (i) fibrinclot retractile (FCR) activity, (ii) the number of actin stress-lines in mouse fibroblasts during growth in culture, and (iii) the sensitivity of actin stress-lines to a powerful actin-depolymerizing factor (ADF), present in plasma and serum of humans and laboratory animals was investigated. Fibroblasts at early passages (2–4) were tested for these parameters at various intervals after seeding (24, 96, and 168 h). The number of actin stress-lines was progressively higher, while the sensitivity to ADF action was progressively lower in cells cultured from 24 to 168 h; the FCR capacity was significantly decreased at 168 h. These data suggest that cells containing weakly polymerized and/or stabilized actin are more active than those containing highly polymerized and/or stabilized actin in triggering fibroblast contraction.     

Fructose-bisphosphatase-deficient mutants of the yeast Schizosaccharomyces pombe

We showed that in the yeast Schizosaccharomyces pombe, fructose-bisphosphatase is not subject to catabolite inactivation as it was observed in Saccharomyces cerevisiae. However, this enzyme activity is sensitive to catabolite repression in both yeasts. Two mutants lacking completely fructose-bisphosphatase activity were found. They were unable to grow on glycerol medium. They were still respiratory competent and exhibited the ability to derepress partially malate dehydrogenase activity. In glucose exponential phase culture, the parental strain lacks completely the fructosebisphosphatase activity due to catabolite repression. In these conditions, the growth is slowed down only in the mutants eventhough both mutants and their parental strain lack this enzyme activity. Normal sporulation and poor spore germination were observed for one mutant whereas, only in the presence of glucose, normal sporulation and normal spore germination were observed for the second mutant. Mendelian segregation of glycerol growth was found for the well germinating mutant. It is of nuclear heredity. The two mutations appeared to be closely linked.Abbreviations FBPase Fructose-1,6-bisphosphatase - fbp ^- genetic symbol for FBPase deficiency - glr ^- symbol for inability to grow on glycerol A. M. Colson is Research Associate au Fonds National de la Recherche Scientifique