Field comparison of disjunct and conventional eddy covariance techniques for trace gas flux measurements.

A field intercomparison experiment of the disjunct eddy covariance (DEC) and the conventional eddy covariance (EC) techniques was conducted over a grass field. The half-hourly water vapor fluxes measured by the DEC were within the estimated uncertainty from the fluxes measured by the EC. On the average there was a slight overestimation (<10%) of the fluxes measured by the DEC during the day and underestimation during the night as compared to the fluxes measured by the EC. As this bias does not appear in the simulated DEC measurements it is likely to be due to instrumental problems. The insensitivity of the quality of the fluxes measured by the DEC method to the deficiencies in the gas analysis shows the robustness of this new approach for measuring the surface-atmosphere exchange of trace gases.

Fluorescence in situ hybridization analysis of minute marker chromosomes in leukemia with monosomy 7.

Monosomy 7 was detected in bone marrow cells from three patients, one with myeloid leukemia, and two others with myelodysplastic syndrome following previous chemotherapy. Fluorescence in situ hybridization (FISH), carried out with an alphoid DNA probe specific for chromosome 7 centromere, showed that a small marker chromosome present in the tumor cells' karyotype of the three patients, was derived from the missing chromosome 7. In two cases, the marker was a ring chromosome, whereas in the third case it was a tiny dot-like chromosome, unnoticed at first examination on R-banded metaphases. In the three cases, the marker was lost in a proportion of tumor cells. FISH experiments suggested that the marker centromere had undergone structural alterations, with a fluorescence pattern distinct from a normal one. On the whole, these data suggest that: firstly, leukemia-associated monosomy 7 results, in a proportion of cases, from a structural event rather than from simple loss of a whole chromosome 7; secondly, interpretation of interphase FISH must be cautious in monosomy 7 evaluation; and thirdly structural alteration of the chromosome 7 derivative alphoid DNA could explain its propensity to segregate unequally and to be lost at mitosis.

A genetic study of angiotensin I-converting enzyme levels in human semen.

The plasma level of angiotensin I-converting enzyme (ACE) has been shown to be under genetic control. An insertion/deletion polymorphism in the ACE gene is associated with differences in the level of ACE in the plasma and inside T-lymphocytes. An ACE isoform is present in large amounts in spermatozoa and is expressed under an alternative, germ cell-specific promoter, whereas ACE present in the seminal fluid is the somatic form of ACE. We have investigated the effect associated with the I/D polymorphism on the level of ACE in seminal fluid and in spermatozoa. No differences in the level of ACE measured in the seminal fluid or in the spermatozoa were associated with the ACE I/D genotypes. We conclude that the modulation of expression associated with the I/D polymorphism is restricted to the somatic ACE promoter. These results also suggest that if one allele modulating the expression of ACE was under positive selection pressure, it was not through an effect on the semen concentration of ACE.

Simple preparation of 1,2-dipalmitoyl-sn-glycero-3-phosphoric acid and deuterated choline derivatives.

Analytically pure 1,2-dipalmitoyl-sn-glycero-3-phosphoric acid was prepared in gram amounts, using a simplified version of a previous procedure. The main step, enzymatic cleavage of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine with freshly extracted phospholipase D, was performed in the presence of chloroform and the crude phosphatidic acid was purified by silica gel column chromatography. The interest of the method was illustrated by the synthesis of two dipalmitoyl phosphatidylcholines selectively deuterated on the polar headgroup.

Influence of methoxy and nitro groups in the oxidative metabolism of naphtho[2,1-b]furan.

In the present study, we have investigated the role of methoxy and nitro groups in the oxidative metabolism of naphtho[2,1-b]furan. Hepatic microsomes were used to investigate the aerobic metabolism of naphtho[2,1-b]furan (compound A), 2-nitro-naphtho[2,1-b]furan (compound B) and 7-methoxy-naphtho [2,1-b]furan (compound C) and comparison of the metabolites formed was made using HPCL analysis and NMR, mass and UV-visible spectrometry. The different metabolic pathways investigated were compared with the previously reported metabolism of 7-methoxy-2-nitro-naphtho[2,1-b]furan (compound D). Naphtho[2,1-b]furan yield metabolites of both the furan and benzene rings, while metabolites formed from 7-methoxy-naphtho[2,1-b]furan and 2-nitro-naphtho [2,1-b]furan were derived entirely as a result of enzymic attack on the first benzene ring.

Cation permeability induced by two aromatic heptaenes, vacidin A and candicidin D on phospholipid unilamellar vesicles.

The cationic permeability induced by two aromatic heptaenes, vacidin A and candicidin D, has been studied on egg yolk L-alpha-phosphatidylcholine single walled vesicles as a function of cholesterol and ergosterol concentration. For comparison amphotericin B and nystatin were also tested. Vacidin A and candicidin D elicit cation permeability in both types of vesicles in the same concentration ranges and exhibit only quantitative differences in cholesterol and ergosterol vesicles. The active concentration range is of the same order of magnitude as the active concentration range of amphotericin B, at variance with what is obtained on biological cells. This difference is interpreted in term of mechanism of action of polyene on both biological and model membranes.

Differential distribution of glutamylated tubulin in the flagellum of mouse spermatozoa.

Using a monoclonal antibody (GT 335) we previously demonstrated that glutamylation is a predominant posttranslational modification of alpha and beta tubulin isoforms in the axoneme of mouse spermatozoa (Fouquet et al., Cell Motil. Cytoskel. 27, 49, 1994). However, we noted that the staining intensity and/or distribution of glutamylated tubulin were not identical using either indirect immunofluorescence (IIF) or immunoelectron microscopy. To test this discrepancy various permeabilization procedures were performed for IIF: methanol or acetone alone or in combination, including freezing pretreatment and with or without paraformaldehyde fixation. Each procedure gave a particular labeling of sperm axoneme. The diversity of axoneme labeling in mouse spermatids and spermatozoa appeared dependent both on the absence or presence of periaxonemal sheaths and permeabilization procedures. For comparison with IIF and to avoid problematic premeabilization treatments a quantitative postembedding immunogold approach was preferred. In these conditions the labeling predominated in the middle piece of the sperm flagellum and decreased progressively in the principal piece. However, the labeling of the terminal piece was similar to that of the middle piece. These results suggested a differential glutamylated tubulin distribution along the axoneme of the mouse sperm flagellum.

Expression of tubulin isoforms during the differentiation of mammalian spermatozoa.

Using the GT 335 mAb we have previously demonstrated a differential expression of glutamylated tubulin isoforms during spermatogenesis and in spermatooza of the mouse and human. Moreover, the proximodistal decrease of the immunolabeling and its predominance in doublets 1-5-6, corresponding to the plane of the flagellar wave, suggested that the glutamylated tubulin could be involved in a functional heterogeneity of microtubules in peripheral doublets of the sperm flagellum. In order to characterize further the importance of glutamylated tubulin in the sperm model, we analyzed tubulin isoforms by immunoblotting and quantitative immunogold, using antibodies to the C-terminal domain of both subunits including non-glutamylated and glutamylated epitopes. The unique differential immunolabeling of the glutamylated tubulin was confirmed with three mAbs 406-3, 392-2 and B3, in addition to GT 335. This differential labeling was interpreted as a differential accessibility of tubulin epitopes since it was greatly reduced in human spermatozoa lacking dynein arms and after motility inhibition of normal spermatozoa by azide pretreatment. We suggest that the glutamylated tubulin interacts with other axonemal and/or periaxonemal proteins which could be involved in flagellar beating and its regulation.

A new model for the reconstruction of biomass history from carbon dioxide emission during batch cultivation of Geotrichum candidum.

A non-structured model has been developed to describe the CO2 emission during growth of Geotrichum candidum on a lactate + peptone-based liquid medium. From the nitrogen and carbon mass balances, it was shown that about 50% of the total CO2 released was from the metabolism of the energy supply for biosynthesis, and the remaining from that for maintenance; thus, CO2 production was considered to be partially associated with growth. The model fitted the experimental data as long as a net growth was observed (0-50 h). The coefficients for growth- and non-growth-associated CO2 production were A = 0.646 (dimensionless) and B = 0.017 h(-1), respectively. From the coefficients of the model and the CO2 history data, the biomass kinetics has been reconstructed, and the calculated biomass concentrations agree fairly well with the experimental data. From this, measurement of the CO2 evolved may be used as an indirect and non-intrusive method of monitoring fungal growth during the first 50 h of cultivation.

[Long term depression]. / Dépression et long terme.

Our practice, in a unit of treatment of dysthymic state being confronted with problems of relapses and recurrences, we have questioned the therapeutic strategies in the long run and their possible assessments. After recalling conceptual and methodological reference about relapses, recurrences and therapeutic assessment, we propose the methods and first results of a retrospective naturalistic study over a period of three years of practice in our treatment unit including 994 cases. We bring out, as soon as the first major depressive episode occurs, a strategy that aims at setting up a therapeutic proceeding tending to treat, beyond the dysthymic episode, the obsessional pre and post-morbid "locks" which seem to "make the bed" of many relapses and recurrences. In this prospect, the interest of serotoninergic molecules with double polarity, anti-depressive and anti-compulsive, is emphasized.

[Reflections on the management of dysthymia and chronic depression]. / Réflexions sur la prise en charge des dysthymies et des dépressions chroniques.

The authors points out the more and more commonly admitted importance of mood disturbances that do not result from major dysthymic states, whether from dysthymies or depressives personalities. He notices that the treatment of such states according to an almost general consensus requires a prescription for a very long anti-depressive treatment. He underlines the problems that can be caused by a long intake of medicines, from a theoretical point of view, concerning psychopathologic reference models as well as from a practical point of view concerning the observance of medicine intake. He suggests some therapeutic axes. Concerning chemotherapy, he suggests choosing a molecule with a serotoninergic tropism that is well tolerated and favours intra-psychic elaboration as well as respects cognitive potentialities. From a therapeutic point of view, he recommends a support that avoids excessive mentalisation, blabbering and obsessive harking but that on the contrary favours the expression of the affect and the shifting of representations on the widened model of psychotherapy inspired by psychoanalysis.

[Elaboration, perlaboration, in the course of antidepressant chemotherapy]. / Elaboration, perlaboration, au cours des chimiothérapies antidépressives.

From the results of an 8 years naturalistic and pragmatical study in a Care Unit for Patients with Dysthymic Disorders at Hôtel-Dieu-Pont-L'Abbé (France), the author points out that there is during long term antidepressive therapies a facilitating action in the psychoaffective elaboration and maturation. The author stresses the importance of agonistic molecules in the serotonin which seem to favour a psychological "working-through" probably because of the lifting of compulsive-obsessive mechanisms present in chronic an residual depressions. The authors underlines the importance of naturalistic and pragmatical studies as an alternative or as a complement to protocolar and controlled studies which are often biased. These biases are increased because of complicated psychometrics and by recent legal measures which tend to lessen the clinical credibility of these "controlled" studies.

[Reflections and perspectives on institutional therapy in neurotic depressions]. / Reflexions et perspectives sur un traitement institutional des dépressions névrotiques,

We have found that an institutional psychothérapy for neurosis could benefit by using elements of the work of Winnicott as well as of the bioenergetic and existential movements. This corresponds to a more and more explicit request from depressed patients who are expecting more from their stay in the hospital than simply to recharge their energy. We thought that our department, because of its size, type of patients, staff and its own orientation would be well adapted to an experience of this kind. In our hospital we try to facilitate in the patient: --regressive experiences; --the perception of "being"; --the symbolic and emotional feeling of the reality of time and place and particularity of the body; --the capacity to repair himself; --playing in the sense of Winnicott: playing with the in and the out (of onesself), the positions of the body, verbal play, play of alternation. --Centering on desire on the interior space, with the capacity to be "alone in the presence on another"; --the discovery of "responsability" and "compassion", also in the sense of Winnicott. We must take into consideration that in order to benefit from this type of therapy, there must be a good enough integration and a pain that is authentically experienced, that is, not acted out, not sutured, and without too many defenses. The results can be appreciated only very subjectively, since improvement is of a qualitative order, in the area of development of being serious existentially. We can perhaps envisage another future for the depressed patient than the interminable repetition of relapses or of beign treated indefinitely. This consists of discovering another way of being, more global, more serious, more authentic (real-self), considering the difficulties involved in the engagement of the realself in an already structured existence.

Behaviour of the yeast Kluyveromyces marxianus var. marxianus during its autolysis.

The lactic yeast Kluyveromyces marxianus var.marxianus (formerly K. fragilis) autolyzates at faster rate than Saccharomyces cerevisiae. During K. marxianus autolysis, quite similar release kinetics were observed for intracellular space markers (potassium ions, nucleotides), cell-wall components (polysaccharides, N-acetyl-D-Glucosamine) and non specific products (amino nitrogen). By Scanning Electronic Microscopy examination, no cell burst was observed, but a variation in cell shape (from ellipsoîdal to cylindrical), as well as a 43% decrease in the internal volume were observed. The mechanism proposed for S. cerevisiae autolysis appeared also likely for K. marxianus.

Immunoelectron microscopic distribution of actin in the spermatids and epididymal spermatozoa of the mouse.

The distribution of actin in spermatids and epididymal spermatozoa of the mouse was examined by electron microscopy with immunogold procedures using two monoclonal antiactin antibodies. Actin was identified by immunoblotting of proteins extracted from either whole spermatozoa or tail fractions. In round spermatids, actin immunolabeling was detected in the subacrosomal space. Labeling increased during the elongation phase, and then decreased and completely disappeared before spermiation. No labeling was found in epididymal spermatozoa and residual bodies. Our results suggest actin redistribution or the absence of G-actin from the head to the flagellum in mature murine spermatids, as previously shown in other studies in various mammals.

Reconstruction of the biomass history from carbon and nitrogen substrate consumption, ammonia release and proton transfer during solid cultures of Geotrichum candidum and Penicillium camembertii.

Geotrichum candidumand Penicillium camembertii were cultivated on the surface of a gelified medium, simulating the composition of the aqueous phase of a Camembert cheese. The relation of their growth with substrate consumption (carbon or nitrogen), metabolite production (ammonia), or proton transfer (deduced from pH by means of the buffer capacity of the medium) was examined. The coefficients associated with cellular biosynthesis and resulting from cellular maintenance were determined. From these coefficients and the considered substrate utilization or metabolite production kinetics, the growth kinetics were reconstructed until the end of growth. The model allowed analysis of biosynthesis and cellular maintenance contributions to the considered kinetics. At the end of growth, almost all the peptone was used for G. candidum biosynthesis, while most of the lactic acid (62%) was used for cellular maintenance. P. camembertii metabolized fewer amino acids as carbon sources, resulting in use of peptone for maintenance (12%), and lactic acid (80%) for cell biosynthesis. For both microorganisms, ammonia production was growth-associated, since this production resulted from the deamination of carbon- and nitrogen-source amino acids, in close relation with peptone consumption.

Tricholongins BI and BII, 19-residue peptaibols from Trichoderma longibrachiatum. Solution structure from two-dimensional NMR spectroscopy.

Two nonadecapeptides, tricholongins BI and BII, which display antifungal and antibacterial activities, have been isolated from in vitro cultures of the fungus Trichoderma longibrachiatum. The peptides were separated by reversed-phase HPLC; their amino acid compositions were determined by gas chromatography and their sequences by positive-ion fast-atom-bombardment mass spectrometry and high-field NMR. These linear peptides, containing mainly hydrophobic L-amino acids, 8-9 2-aminoisobutyric acid residues and exhibiting an acetylated N-terminal residue and an amino alcohol C-terminal leucinol belong to the peptaibol class. The methanol solution structure of tricholongins BI and BII has been investigated using both one- and two-dimensional NMR techniques. The total 1H-NMR and 13C-NMR assignments are given. By a combination of the 3JNH,C alpha H coupling constant values, temperature coefficients of the NH and CO groups, amide hydrogen/deuterium-exchange rate measurements and NOE data, a secondary structure for tricholongins in solution has been proposed. Both peptides adopt a similar alpha-helical conformation with a hinge around Pro13 resulting from two 3(10) bonds. The results suggest that the N-terminus contains mixed alpha/3(10) bonds. The membrane permeability modifications induced by tricholongins have been assayed by the use of liposomes composed of egg phosphatidylcholine with 20-30% cholesterol. The peptide-induced leakage of an entrapped fluorescent probe has been followed by fluorescence spectroscopy. In a concentration range of 0.13-0.31 microM, tricholongins induce the leakage of 50% of the entrapped material in 20 min.