A mathematical model of growth and alkaloid production in the submerged culture of Claviceps purpurea

A mathematical model of the batch cultivation of Claviceps purpurea was formulated. The main attention was devoted to the effect of exocellular and intracellular phosphate on the growth of the mycelium and production of clavine alkaloid under experimental conditions without limitation by carbon and nitrogen sources. The method of nonlinear regression was used ot predict the optional technological regime of the phosphate addition in the batch culture at different time intervals of additions.     

Decouverte de Septorella brachycera grambast et de Septorella ultima Grambast (Charophytes,Clavatoracees) dans le Maestrichtien superieur des Petites Pyrenees. Consequences stratigraphiques

The discovery of an assemblage of Clavatoraceae including Septorella brachycera and S. ultima in the “Marnes d'Auzas” (upper Maestrichtian) of the Petites Pyrénées constitutes the first element of comparison between the upper Cretaceous of the Petites Pyrénées and Provence, but creates a problem with regard to the subdivision of the provencial Rognacian, based, in part, on the superposition of these two species.     

Autoradiographic studies of a glucocorticoid agonist and antagonist: Localization of 3H-corticosterone and 3H-cortexolone in mouse brain

Summary The localization in the mouse brain of corticosterone, the natural glucocorticoid in the mouse, and cortexolone, reported to be a glucocorticoid antagonist, was studied by autoradiography 30 min after in vivo administration of the tritiated compounds.After ³H-corticosterone (³HB) injection, radioactivity was preferentially concentrated in cell nuclei of several structures within the limbic system, and in nuclei of certain neurones of the cerebral cortex and medulla oblongata. This nuclear concentration was abolished after injection of ³H-corticosterone with an excess of unlabelled corticosterone. After ³H-cortexolone (³HS) injection, a diffuse radioactivity was observed throughout the brain. However, a higher concentration of grains was present in the ventral nucleus arcuatus and in the infundibulum. When excess unlabelled cortexolone was administered with ³H-cortexolone this preferential accumulation of grains was abolished.The accumulation of ³H-cortexolone in the medial basal hypothalamic region suggests that cortexolone concentrates preferentially in dexamethasone (DM) target regions, and in addition the autoradiographic results show that the cortexolone-receptor complex does not accumulate in the cell nucleus.

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Résumé La localisation au niveau du cerveau de souris de la corticostérone, qui est le glucocorticoide naturel chez la souris, et de la cortexolone, démontrée comme étant un antagoniste des glucocorticoides, est étudiée par autoradiographie 30 min après injection in vivo des composés tritiés.Après injection de ³H-corticosterone (³HB), la radioactivité se concentre préférentiellement dans des noyaux cellulaires de plusieurs structures du système limbique et dans les noyaux de certains neurones du cortex cérébral et du bulbe rachidien. Cette concentration nucléaire est abolie après injection de ³H-corticostérone en présence d'un excès de corticostérone non radioactive. Après injection de ³H-cortexolone (³HS), une distribution diffuse de la radioactivité est observée dans tout le cerveau, cependant, une concentration plus élevée de grains d'argent est présente dans la partie ventrale du nucleus arcuatus et dans l'infundibulum. Après injection de ³H-cortexolone en présence d'un excès de cortexolone non radioactive, cette accumulation préférentielle des grains est abolie.L'accumulation de la ³H-cortexolone dans la région hypothalamique suggère que la cortexolone se concentre préférentiellement dans la région cérébrale qui contient les sites de liaison de la dexaméthasone et de plus, les résultats autoradiographiques montrent que le complexe cortexolone-récepteur ne s'accumule pas dans le noyau cellulaire.

     

Autoradiographic localization of 3H-glucocorticoids and 3H-cortexolone in mouse pituitary

Summary Autoradiograms of mouse pituitaries were prepared 30 min after injection of ³H-dexamethasone (³HDM), ³H-corticosterone (³HB) and ³H cortexolone (³HS) either alone or in the presence of competing unlabelled steroids. ³H-dexamethasone accumulated in cell nuclei of both the pars distalis and the pars nervosa but not in those of the pars intermedia. This preferential accumulation (nuclear/cytoplasmic grain density, 41) was abolished by the concurrent administration of excess dexamethasone. ³H-corticosterone, to a much less marked extent than ³H-dexamethasone, accumulated in cell nuclei of the pars distalis but not in those of the pars intermedia and the pars nervosa. Excess unlabelled corticosterone diminished nuclear grain density in the pars distalis. After ³H-cortexolone injection, preferential nuclear uptake was not observed. In a second series of experiments, excess dexamethasone (10 x, 100 x), corticosterone (100 x, 300 x) and cortexolone (100 x, 300 x) administered with ³H-dexamethasone were without effect on cytoplasmic grain density but totally abolished preferential nuclear accumulation. Parallel biochemical studies on kidney cytoplasmic preparations from the same animals showed no differences in total cytoplasmic radioactivity between treatments but marked differences in cytoplasmic bound ³H-dexamethasone. The results demonstrate: i) that dexamethasone binds specifically to cell nuclei of the pars distalis and the pars nervosa and that this nuclear concentration is abolished by competing corticosterone and cortexolone as well as dexamethasone; ii) that corticosterone localizes in cell nuclei of the pars distalis but much less markedly than dexamethasone; iii) that cortexolone fullfils the criteria of a glucocorticoid antagonist at the pituitary cell level.

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Résumé La localisation au niveau de l'hypophyse de souris de la ³H-dexaméthasone (³HDM), de la ³H-corticostérone (³HB) et de la ³H-cortexolone (³HS) est étudiée par autoradiographie 30 min après l'injection des composés tritiés seuls ou en présence de stéroides compétiteurs non radioactifs. La ³H-dexaméthasone s'accumule dans des noyaux cellulaires de la pars distalis et de la pars nervosa mais pas dans des noyaux de la pars intermédia. Cette accumulation préférentielle (densité des grains d'argent nucléaire/cytoplasmique: 4/1) est abolie par l'injection de ³H-dexaméthasone en présence de dexaméthasone non radioactive. La ³H-corticostérone se concentre avec une intensité beaucoup plus faible que la ³H-dexaméthasone uniquement dans certains noyaux de la pars distalis. Un excès de corticostérone non radioactive diminue la densité nucléaire des grains d'argent des cellules de la pars distalis. Après injection de ³H-cortexolone, aucune accumulation préférentielle de grains d'argent n'est observée dans les noyaux cellulaires. Dans une seconde série d'expériences, la ³H-dexaméthasone est injectée soit en présence d'excès de dexaméthasone (10x, 100x) ou de corticostérone (100x, 300x) ou de cortexolone (100 x, 300 x). Dans ces conditions, la densité cytoplasmique des grains d'argent n'est pas différente de celle observée après injection de ³H-dexaméthasone seule mais l'accumulation préférentielle de la radioactivité dans les noyaux cellulaires est abolie. Des études biochimiques parallèles effectuées sur des préparations cytoplasmiques de rein des mêmes animaux montrent que la radioactivité cytoplasmique totale ne varie pas tandis que la liaison cytoplasmique de la ³H-dexaméthasone diffère suivant les traitements. Ces résultats montrent i) que la dexaméthasone se fixe spécifiquement dans des noyaux cellulaires de la pars distalis et de la pars nervosa et que cette fixation nucléaire est abolie aussi bien par des excés de corticostérone ou de cortexolone que par des excès de dexaméthasone, ii) que la corticostérone se localise dans des noyaux cellulaires de la pars distalis mais beaucoup moins intensément que la dexaméthasone, iii) que la cortexolone se comporte comme un antagoniste des glucocorticoides au niveau de la cellule hypophysaire.

     

Discriminant analysis on cells from developing squamous cancer of the respiratory tract

Cytologic preparations made from the tracheobronchial tree taken by the Schreiber catheter have been scanned by three color microphotometry. The digitized cell images were processed by the analytical cytodiagnostic programs of the TICAS system. Cells were sorted into two control groups and five groups of increasing atypia ranging from normal epithelium to invasive squamous cell carcinoma. Standard statistical tests, including Wilk's Lambda, Rao's V, and the Kruskal-Wallis tests are performed on these subsets of cell image features. This study demonstrates that discriminant analyses permit differentiation between normal cells and those from marked atypia or carcinoma and that the classification achieves a high degree of agreement with visual assignment.     

Synthesis and chemical behaviour of D-glucosyl esters of glutamic acid having the side-chain carboxyl group involved in the glycosidic linkage.

Simultaneous and stepwise deprotection of the fully benzylated D-glucosyl esters of 1-benzyl N-benzyloxycarbonyl- and N-tert-butyloxycarbonyl-L-glutamic acid (1 and 5, respectively) have been examined. Catalytic hydrogenation of 1 led to intramolecular aminolysis to give pyroglutamic acid and D-glucose, but similar treatment in the presence of trifluoroacetic acid afforded both anomers of 1-O-(L-gamma-glutamyl)-D-glucopyranose, which were characterized as trifluoroacetates (2alpha and 2beta) and converted into 2,3,4,6-tetra-O-acetyl-1-O-[1-methyl N-(acetyl)-L-glutam-5-oyl]-D-glucopyranose (4) which was also prepared by a definitive method. Hydrogenolysis of 5 gave both anomers of 1-O-[N-(tert-butyloxycarbonyl)-L-gamma-glutamyl]-D-glucopyranose (6), which, upon treatment with trifluoroacetic acid at - 10 degrees, afforded 2alpha and 2beta, respectively. The structure of 6beta was established by its conversion into 2,3,4,6-tetra-O-acetyl-1-O-[1-methyl N-(tert-butyloxycarbonyl)-L-glutam-5-oyl]-beta-D-glucopyranose (7beta), whereas similar treatment of 6alpha gave a mixture of 1,3,4,6-tetra-O-acetyl-2-O-[1-methyl N-(tert-butyloxycarbonyl)-L-glutam-5-oyl]-alpha-D-glucopyranose (9) and 7alpha. A 1 leads to 2 acyl migration occurred during esterification of the aglycon carboxyl group of 6alpha with diazomethane to give 2-O-[1-methyl N-(tert-butyloxycarbonyl)-L-glutam-5-oyl]-alpha-D-glucopyranose (8).     

Reciprocal allopolyploid grasses (Festuca × Lolium) display stable patterns of genome dominance

Allopolyploidization entailing the merger of two distinct genomes in a single hybrid organism, is an important process in plant evolution and a valuable tool in breeding programs. Newly established hybrids often experience massive genomic perturbations, including karyotype reshuffling and gene expression modifications. These phenomena may be asymmetric with respect to the two progenitors, with one of the parental genomes being “dominant.” Such “genome dominance” can manifest in several ways, including biased homoeolog gene expression and expression level dominance. Here we employed a k-mer–based approach to study gene expression in reciprocal Festuca pratensis Huds. × Lolium multiflorum Lam. allopolyploid grasses. Our study revealed significantly more genes where expression mimicked that of the Lolium parent compared with the Festuca parent. This genome dominance was heritable to successive generation and its direction was only slightly modified by environmental conditions and plant age. Our results suggest that Lolium genome dominance was at least partially caused by its more efficient trans-acting gene expression regulatory factors. Unraveling the mechanisms responsible for propagation of parent-specific traits in hybrid crops contributes to our understanding of allopolyploid genome evolution and opens a way to targeted breeding strategies.