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J Gaillard

Publications and source records attributed to J Gaillard.

At least 19 recordsLinked to original sources
PubMed1992

Expression in Escherichia coli and characterization of a recombinant 7Fe ferredoxin of Rhodobacter capsulatus.

The 7Fe ferredoxin of Rhodobacter capsulatus (FdII) could be expressed in Escherichia coli by cloning the fdxA gene coding for FdII downstream from the lac promoter. The expressed recombinant ferredoxin appeared as a brown protein which was specifically recognized in E. coli cell-free extracts by anti-FdII serum. The purified recombinant ferredoxin was indistinguishable from R. capsulatus FdII on the basis of its molecular, redox and spectroscopic properties. These results indicate that the [3Fe-4S] and [4Fe-4S] clusters were correctly inserted into the recombinant ferredoxin.

Cloning, Molecular↗
PubMed1992

Sequence-specific assignments of the 1H nuclear magnetic resonance spectra of reduced high-potential ferredoxin (HiPIP) from Chromatium vinosum.

The 1H resonances of the high-potential [4Fe-4S]2+ ferredoxin from Chromatium vinosum have been assigned through conventional sequential methodology applied to 2D NMR spectra. Almost 80% of the residues were identified using standard 2D COSY, HOHAHA, and NOESY pulse sequences. These residues correspond to four segments of the primary structure that do not interact strongly with the iron-sulfur cluster. A minor correction to the amino acid sequence is strongly suggested by these NMR data. Additional protons more sensitive to the proximity of the cluster were assigned by a combination of NOESY experiments with fast repetition rates and short mixing times and of HOHAHA spectra recorded with reduced spin-lock duration aimed at compensating for the short relaxation rates. Hence, the contributions of 79 residues out of 85 were identified in NMR spectra, among which the assignments of 64 residues were completed. Even the fastest relaxing protons, like those of the cysteine ligands, could be correlated, partly because the strong hyperfine shifts isolate them from the crowded diamagnetic region. However, other protons, in particular those involved in NH-S hydrogen bonds with the iron-sulfur cluster, were more difficult to identify, most probably because their relatively broad signals overlapped with those of protons not or less perturbed by the active site. The availability of the major part of the 1H NMR assignments has enabled the detection and identification of many interresidue NOESY cross peaks. These data are in full agreement with the elements of secondary structure previously revealed by X-ray crystallographic analysis of the protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1991

Rapid inactivation of plant aconitase by hydrogen peroxide.

Preincubation of potato (Solanum tuberosum) tuber mitochondria with 300 microM-H2O2 for 10 min nearly stopped the State 3 rate of citrate oxidation. Addition of isocitrate resulted in resumption of O2 uptake. The State 3 rates of succinate, external NADH and 2-oxoglutarate oxidation were unaffected by H2O2 over the dose range 50-500 microM. Preincubation of mitochondria with 300 microM-H2O2 for 5 min unmasked in the matrix space a paramagnetic signal with a peak at a g value of approx. 2.03. Aconitase was purified over 135-fold to a specific activity of 32 mumol/min per mg (with isocitrate as substrate) from the matrix of potato tuber mitochondria. The native enzyme was composed of a single polypeptide chain (molecular mass 90 kDa). Incubation of purified aconitase with small amounts of H2O2 caused the build up of a paramagnetic 3Fe cluster with a low-field maximum of g = 2.03 leading to a progressive inhibition of aconitase activity. The results show that aconitase present in the matrix space was the major intramitochondrial target for inactivation by H2O2.

Aconitate Hydratase↗
PubMed1990

Purification and characterization of a 7Fe-ferredoxin from Rhodobacter capsulatus.

A ferredoxin was purified anaerobically from Rhodobacter capsulatus grown photoheterotrophically with excess ammonia. This ferredoxin, called ferredoxin II (FdII), had a molecular weight of approximatively 15,000 by gel filtration and 14,000 by SDS polyacrylamide gel electrophoresis indicating that it is monomeric. Its absorption spectrum (oxidized form) exhibited maxima at 280 nm and 400 nm; the A400/A280 ratio had a calculated value of 0.55. Chemical determination of its iron and sulfur atom content, the value of the extinction coefficient at 400 nm (epsilon 400 = 26.8 mM-1 cm-1) and EPR spectra indicated that ferredoxin II contained one [3Fe-4S] and one [4Fe-4S] cluster. Upon reduction with excess dithionite only the [3Fe-4S] cluster became reduced. The reduction of both clusters was achieved by using 5-deazaflavin as photocatalyst. Ferredoxin II was also purified from bacteria grown under nitrogen limiting (nif derepressing) conditions. In in vitro assays, ferredoxin II catalyzed electron transport between illuminated chloroplasts and nitrogenase.

Amino Acids↗
PubMed1989

[Value of hemodynamics in the surgical indications of emphysema].

The authors present the results of a preliminary study designed to define the surgical indications in diffuse pulmonary emphysema based on the data of haemodynamic investigations. This series consists of 10 patients identified for disabling dyspnoea, diffuse emphysema and dynamic expiratory compression documented by the data of right micro-catheterisation by a DEP/DIP ratio greater than 2. The surgical operation consisted of reduction in the lung volume, the results of which were defined by pre- and postoperative examinations. In this way, it is possible to distinguish 3 groups of patients: one group was markedly improved, another was moderately improved and the third group continued to deteriorate analysis of the results suggests the determinant role of dynamic factors, in particular haemodynamic factors. The role of the diaphragm is demonstrated by modifications in its radius or curvature.

Diaphragm↗
PubMed1989

Lymphoproliferative syndrome associated with c-myc expression driven by a class I gene promoter in transgenic mice.

We have produced transgenic mice carrying an H-2K/human c-myc fusion gene. In this construct, the human c-myc proto-oncogene expression is driven by the 5' flanking sequences (including promoter) of the class I H-2Kb gene, which have previously been shown to direct the expression of a marker gene, the human growth hormone (hGH), in most tissues of H-2K/hGH transgenic mice. Comparative analysis, by S1 nuclease mapping, of the H-2K and human c-myc gene expression in different organs of the H-2K/myc mice shows that exogenous c-myc and endogenous H-2K expression is found in most organs examined. However, the liver is a notable exception, for here c-myc expression is very weak. The exogenous c-myc expression is maximal in lymphoid organs of all H-2K/myc transgenic strains. One strain, H-2K/myc 27, hereditarily develops a lymphoproliferative syndrome which eventually leads to death. The H-2K/myc 27 lymphoid tissues are profoundly abnormal: pre-B cells as well as mature B cells are underrepresented in the bone marrow but the thymus as well as lymph nodes are largely infiltrated by B cells. Moreover, in the thymus, the proportions of the different thymic cell populations are altered. However, in the other H-2K/myc transgenic strains, even in those expressing a comparable or even higher level of myc, no pathology has been observed over a period of 20 months. Our results, therefore, demonstrate that constitutive enforced c-myc expression might disturb lymphocyte development, but does not directly lead to malignancy.

Animals↗
PubMed1989

[Cervicofacial non-Hodgkin's malignant lymphoma. Classification, prognosis and treatment apropos of 65 cases].

The approach to non hodgkins malignant lymphomas (NHML) has changed in recent years, notably because of advances in pathological evaluation due to histo-immuno-labelling leading to a more accurate classification. Such pathology being relatively common in the cervical facial region, with a figure of 10 to 25%, this report concerns the personal experience of the authors based upon 65 cases treated in the department between 1975 and 1985.

Adolescent↗
PubMed1988

Hydrogen-1 nuclear magnetic resonance of the nitrogenase iron protein (Cp2) from Clostridium pasteurianum.

Proton NMR spectra (250 MHz) of the nitrogenase iron protein from Clostridium pasteurianum (Cp2) were found to display 9 or 10 paramagnetically shifted resonances in the 15-50 ppm range. The most shifted resonances belonged to two approximately equal subsets having temperature dependences of opposite sign. The latter occurrence is consistent with the interaction of the corresponding protons with an antiferromagnetically coupled metal center. The number of proton resonances of Cp2, their positions, and their temperature dependences were similar to those observed in spectra of (4Fe-4S)+ ferredoxins, particularly those of the latter that contain a single tetranuclear cluster, such as the ferredoxin from Bacillus stearothermophilus. The effects of several adenine nucleotides on the paramagnetically shifted proton resonances of Cp2 have been investigated. Whereas MgAMP had no effect at all, MgADP and MgATP were found to induce different modifications, which in both cases involved approximately half only of the shifted proton resonances. These data suggest that nucleotide binding affects mainly one part of the iron-sulfur cluster. A remarkable feature of the spectra of Cp2 in the presence of MgATP is the grouping of the shifted proton resonances in sets of two or four having identical chemical shifts and temperature dependences. A nearly perfect 2-fold symmetry is thus suggested for the arrangement of the cysteine protons around the active site. These observations lend support to the proposal that the (4Fe-4S) cluster is held symmetrically between the two identical subunits and are consistent with the existence of two MgATP binding sites on nitrogenase iron proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1988

[Long-term survival of surgically treated lympho-epithelial thymomas].

The authors report the results of a multi-centre trial on 500 cases of lymph-epithelial thymoma (TLE) treated by 14 surgical teams. Most typically a tumour of the adult in the fifth decade, occurring most commonly in women (60%), one in every two cases of TLE occurs in auto-immune disease: usually myasthenia. Most often (3 times out of 4) the disease is latent and occupies the middle (40%) or superior mediastinum (30%). In 15% of cases the pulmonary radiograph is normal. Radical surgery is possible in 75% of cases, otherwise it is incomplete or even reduced to a simple biopsy. The 15 year prognosis obtained using actuarial survival curves is based on the surgical-anatomical classification of the study group of thymic tumours (GETT) giving: for stage I: a survival of 80% for stage II to IVA of 40% and for stages III to IVB of around 10%. Finally it should be noted that existence of a recurrence after a complete surgical excision (stage I) poses the problem of post-operative radiotherapy and the associated total thymectomy. Also, the identical prognosis after biopsy or incomplete surgery (IIIA and IIIB) with an increased morbidity for incomplete surgery. Finally the confirmation that pleural involvement (IVA) is not as adverse a factor as one would have supposed.

Adolescent↗
PubMed1987

Structural requirements for the induction of "immunological castration" by linear monomeric LHRH-lys-MDP administered in saline.

It was previously shown that "castration" could be obtained in male mice by immunizing them in saline with a conjugate referred to as LHRH-Lys-MDP and containing the decapeptide hypothalamic hormone LHRH covalently linked to the adjuvant glycopeptide MDP-Lys. Since coupling was made using carbodiimide, it could have produced oligomers or isomers as well as monomers. In the present investigation male and female mice were immunized in saline with a linear monomeric MDP linked LHRH molecule obtained by total synthesis. Histological studies showed gonadal alterations in both male and female mice. The study of analogs provided a correlation between the "castrative" activity of LHRH-Lys-MDP and its chemical and antigenic structures. However, because LHRH antibody levels were not very high, mechanisms other than antibody response are discussed. Such totally synthesized molecules including a safe adjuvant could make a clinical use of LHRH immunization possible in endocrine-dependent cancers.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1987

Immortalization of precursors of endodermal, neuroectodermal and mesodermal lineages, following the introduction of the simian virus (SV40) early region into F9 cells.

F9 embryonal carcinoma cells were transfected with a hybrid plasmid containing the early genes of the simian virus SV40 under the control of the adenovirus type 5 E1A promoter [21]. These cells were induced to differentiate in aggregates in the presence of retinoic acid (RA). Unlike the derivatives of F9 that are usually obtained in this manner, the plasmid-containing cells were both programmed and immortalized; in addition, expression of the SV40 T antigen was now triggered. These immortalized cells could be separated into three classes: (1) extraembryonic derivatives, (2) embryonic differentiated tissues, (3) immature cells surrounding the differentiated cells. When injected into mice, the mixture of these cells gave rise to multipotential tumors. From the immature cells, committed precursors of the neuroectodermal, endodermal, and mesodermal pathways could be isolated by cloning and selection according to: (a) their specific pattern of differentiation in the tumors and (b) the occurrence of specific markers in the differentiated progeny. The isolation of stable immortalized cell lines corresponding to precursors of the three primitive germ layers and capable of differentiating reproducibly along a particular restricted pathway should facilitate molecular studies on early embryonic development in mouse.

Animals↗
PubMed1987

Localization of H blood group antigen in ectoblastic derivatives of murine teratocarcinoma.

Ectoblastic derivatives (ectodermal and neuroectodermal components) constitute more than 90% of all structures in the murine teratocarcinoma derived from the PCC4-aza-1 line. This tumor was labeled immunocytochemically with fluoresceinated antibodies to A, B and H blood groups. A and B antigens were always noted to be absent from all structures of the three germ layers. With anti-H, however, embryonic and fetal endodermal components, e.g. alimentary or respiratory duct-like structures, gave positive staining. Mesodermal components, i.e. bone and cartilage structures, fibroblasts and myocytes of mature or embryonal type, were negative. Immature and mature ectodermal components, viz. epidermoid cysts or islets, were always positive. Neuroectodermal components, neuroblastic cysts and differentiated neuronal, glial and ependymal elements were always negative. Ectoblastic and/or neuroectoblastic individual cells or cell clusters, observed in the vicinity of positive differentiating ectodermal and neuroectodermal structures, were positive. Similar cells or clusters were negative when located close to negative neuroectodermal components. The undifferentiated, embryonal carcinoma cells and structures were always negative. These observations are compared to the staining patterns of H antigen in murine embryos and adult mice and in human teratocarcinomas. It is suggested that poorly differentiated, morphologically similar ectoblastic and/or neuroectoblastic structures are positive, if they concern ectodermal components, and negative, if they belong to neuroectodermal components, with the exception of some primary sensory cells that are positive. These last cells are also positive in normal fetal and adult tissues.

ABO Blood-Group System↗