Computation of the fraction of induced cells in enzyme induction systems

A theoretical model is developed for continuous multistage enzyme production systems, which consist of a growth fermentor used for growing microorganisms rapidly without enzyme production and a subsequent system of induction reactors in which enzymes induction and production occurs. The model allows the computation of the fraction of induced cells residing in the induction reactor for organisms exhibiting a lag phase in enzyme induction. For this model a general analytical solution was obtained for the cumulative internal residence time distribution of a series of n well-stirred vessels with a recycle. The theoretical results are compared in a preliminary way with experimentally measured cellulase productivities of continuous multistage cellulose fermentations with Trichoderma viride QM 9414.     

影响光合细菌类胡萝卜素形成因素的研究

对已初步确认为球形红假单胞菌属的S—1菌株进行了类胡萝卜素形成因素的研究。通过对光照强度、温度、pH、碳源、氮源、生长因子和无机盐成份等培养条件的探讨,找到了适合类胡萝卜素形成的条件,为开发光合细菌类胡萝卜素提供了依据。     

Identification and cloning of a novel heterogeneous nuclear ribonucleoprotein C-like protein that functions as a transcriptional activator of the hepatitis B virus enhancer II.

Liver specificity of hepatitis B virus (HBV) replication has been attributed to the action of its second enhancer (EII). We report here the characterization of EII and the subsequent isolation of a novel liver-specific DNA-binding protein which binds to and activates EII. The cDNA clone of the protein, designated E2BP, was isolated from a lambda gt11 expression library constructed from the hepatoma cell line HuH-6 which was screened with a binding site probe derived from EII. Sequence analysis of E2BP revealed 86.6% homology with a rat heterogeneous nuclear ribonucleoprotein C protein sequence, while conformational studies suggest a helix-loop-helix motif as a DNA-binding site. Cloned E2BP expressed in human fibroblasts by transient transfection displayed EII binding and activating characteristics similar to those of native E2BP in hepatocytes.     

Reduction mammaplasty with a circular folded pedicle technique.

A personal technique for breast reduction utilizing a circular dermal-breast pedicle is presented. After a cutaneous glandular excision in the inferior pole and glandular excision in a discoid shape under the central area, the pedicle is folded on itself to produce a direct elevation of the nipple-areola complex into its new position, to enhance projection, and to act as a central support. A rational economy of scars is obtained by a central convergence of the breast tissue that stretches the breast periphery and by sutures finishing in the inferoareolar area. There the skin excess is removed to avoid scar lengthening in both the caudal and cranial directions. Evaluation of long-term results reveals maintenance of breast projection, preservation of the inframammary fold to inferior areola distance, and minimal residual scarring.     

Quantitation of Sertoli cell-germ cell desmosome gap junctions in relation to meiotic divisions in the male rat.

Desmosome-gap (D-G) junctions were quantified in relation to germ cell meiosis in the male, specifically to test the hypothesis that the loss of these junctions is related to successful passage of cells through diplotene phase of Meiosis I and the two cytokineses that follow. Such a hypothesis has been proposed as the cause for the resumption of meiosis that occurs prior to ovulation in the female. D-G junctions were quantified in pachytene spermatocytes (stage XII), diplotene spermatocytes (stage XII), secondary spermatocytes (stage XIV) and step 1 spermatids (stage I). These were referred to as the cells of interest as compared with spermatocytes (zygotene spermatocytes, zygotene spermatocytes, pachytene spermatocytes, pachytene spermatocytes) in the same stages, respectively, that served as controls termed control cells. Since gap junctions are not easily recognized in the average sectioned profile of a desmosome-gap junction, only the desmosomal component was quantified. The data were expressed as both numbers and length of junctions per tubule, per cell profile and per unit lineal membrane length to overcome errors inherent in the methodologies utilized. There was no indication that numbers of junctions changed specifically in the cells of interest after passage through diplotene suggesting that these junctions do not have a comparable role in meiotic continuance in the male as proposed for the female. Interestingly, the control cells always showed greater numbers and length of junctions than the cells of interest suggesting that junction may relate more to the period of initiation of meiosis than to its continuance.     

Contribution to the knowledge of the savanna and forb-rich communities of Pinar del Rio Province (Cuba)

Phytosociological analysis of savanna and forb-rich communities in the Pinar del Rio Province was done in the area of Remates de Guane; one locality lies on the seashore in the western part of the province. Altogether six associations were distinguished. Five of them, viz.Sclerio curtissii-Centelletum erectae, Schultezio guianensis-Rhynchosporetum fascicularis, Cassio diphyllae-Hypericetum stypheloidis, Polygalo squamifoliae-Dichromenetum seslerioidis andPhyllantho juncei-Aristidetum, all newly described in this paper, are classified into the order ofAcoelorapho-Colpothrinacetalia Bal.-Tul. inBal.-Tul. etCapote 1985 with two alliances. One association, thePaspalo debilis-Asteretum grisebachii Bal.-Tul. etCapote 1992, was put into the order ofAsteretalia grisebachii Bal.-Tul. inBal.-Tul. etCapote 1992 with one alliance bound to inland moving dunes. The plant composition reflects soil quality, above all the water regime. Very interesting is the presence of theByrsonimo crassifoliae-Andropogonetalia teneris-species in the association ofPolygalo-Dichromeneteum seslerioidis indicating the rich presence of stones in the upper part of the soil profile.     

Evidence for the mannosylation of a non-histone protein in monkey liver chromatin

Summary Mannose is incorporated in monkey liver chromatin by the means of a nuclear membrane mannosyl-transferase.¹⁴C-labelled chromatin is dissociated either by sulfuric acid or 6 M urea and 0.4 M GuCl. The fractions then enriched in non-histone¹⁴C-labelled proteins are excluded from Ultro-gel AcA 202, their analysis in SDS-polyacrylamide gel electrophoresis shows that radioactivity fits with one major protein band, confirming the presence of at least a non-histone protein labelled with mannose in monkey liver chromatin, with an apparent molecular weight of 13 000.     

A new savanna-like community of the sierra del rosario mountains,Cuba

This communication describes a new savanna-like community, theBletio purpureae-Andropogonetum gracilis Balátová-Tulá?ková etR. Capote ass. nov., found in the woodless eastern part of the Sierra del Rosario Mountains (western part of Cuba). From the phytosociological point of view, it belongs to the allianceAchlaenion piptostachyae Balátová-Tulá?ková all. nov., the orderAchlaenetalia piptostachyae Balátová-Tulá?ková ord. nov., and the classSclerio baldwinii-Andropogonetea gracilis Balátová-Tulá?ková cl. nov. In the area under study four subassociations were distinguished: theBletio-Andropogonetum typicum Balátová-Tulá?ková et.R. Capote subass. nov., theB.-A. rhynchosporetosum fascicularis Balátová-Tulá?ková etR. Capote subass. nov., theB.-A. cassietosum aeschynomenes Balátová-Tulá?ková etR. Capote subass. nov., and theB.-A. stenandrietosum droseroidis Balátová-Tulá?ková etR. Capote subass. nov.     

Differentiation between the somatostatin inhibition and the post-somatostatin rebound observed on growth hormone secretion in vitro

A rebound in growth hormone secretion following somatostatin treatment has been shown in several systems where somatostatin suppresses secretion of the hormone. We have developed an in vitro system in which isolated and cultured pituitary cells were perfused after mild trypsinization. After washing, these cells retained their sensitivity and secreted growth hormone (GH) in response to physiological activators (norepinephrine, dopamine, serotonin) or inhibitors (somatostatin) as well as pharmacological activators (PGE2). The variation in GH secretion occurred within a minute after commencement of the infusion and was as rapidly reversible and repeatable minutes later. During somatostatin infusion the GH secretion was not totally suppressed (residual secretion (mean +/- S.D.) 34 +/- 7%). After the infusion a rapid rebound in GH secretion occurred, reaching levels in excess of the pretreatment value of 138 +/- 13%. This rebound effect occurred at doses higher than (10(-10)M) but not at lower doses, even when significant inhibition was observed. The inhibitory effect is of greater magnitude than the rebound effect (rebound = inhibition X 57 +/- 7% (mean +/- S.D.)). Furthermore, rebound was not enhanced by prolongation of somatostatin infusion. These latter results indicate that the rebound in secretion cannot be explained on the sole basis of storage of intracellular GH during somatostatin infusion and in fact suggest the involvement of a process of GH degradation and/or an inhibition of GH synthesis.     

Effets du rubidium et du césium sur la croissance et la nutrition minerale des characees

Résumé Le rubidium et le césium introduits à l'état de chlorure dans le milieu de culture ont à faible dose un effet stimulant sur la croissance de Chara fragilis et de Chara vulgaris. La résistance de ces végétaux à l'action toxique des deux ions est accrue par l'addition de potassium au milieu.Les analyses chimiques confirment que le rubidium et le césium sont antagonistes vis-à-vis du potassium et du sodium alors qu'ils ne modifient pas de manière significative le taux de calcium.

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Chara fragilis and Chara vulgaris were cultivated in a natural medium containing rubidium and caesium as chloride.The growth of Characeae was increased after culture in the solutions containing Rb and Cs in small amount. The resistance to the toxic effects of these two ions is enhanced if potassium chloride is added to the medium.Quantitative analyses indicate that Rb and Cs decrease the rate of Na and K but have no significative influence on the rate of Ca.

Université de Dijon, Laboratoire de Nutrition minérale des Végétaux