Physiological and psychological response to a three-month mental strain period in students

Biochemical and immunological parameters, physical and mental performance, subjective complaints and behavioural characteristics were compared before and after 14 final examinations undertaken by 64 students during a three-month examination period. A decrease in cholesterol, triglycerides, HDL-cholesterol, physical performance and an increase in LDL/HDL cholesterol quotient, lactate level, mental performance were accompanied by a lower frequency of mental complaints and higher frequency of physical complaints. From the multidimensional variance and discriminant analysis 17 of the 44 variables discriminated between the state prior to and after the examination period. The results are interpreted in terms of the psychophysiological adaptation to adequate mental stress.     

Isolation of heparan sulfates with antithrombin III affinity and anticoagulant potency from BALB/c 3T3, B16.F10 melanoma, and cutaneous fibrosarcoma cell lines

The heparan sulfates synthesized in vitro by three cell lines were isolated by proteolysis and preparative anion exchange chromatography and purified free of other glycosaminoglycans by selective enzymatic degradation. The isolates from the medium of BALB/c 3T3 fibroblasts, B16.F10 melanoma cells, and a cutaneous fibrosarcoma line, along with that from the detergent-extracted cell layer of the fibroblasts, were affinity-fractionated on columns of matrix-immobilized human antithrombin III. Each heparan sulfate contained subfractions with high affinity for the proteinase inhibitor, ranging from 3-34% of the starting material. The high affinity species possessed measurable anticoagulant activities by a clotting assay (6 to 30 units/mg). Since none of the lines were derived from cell types having any known biological role in vascular homeostasis, we suggest that anticoagulant activity of the glycosaminoglycan is a random property of its primary structure.     

Study of plasmids isolated from saccharolytic Clostridia: Construction of hybrid plasmids and transfer toEscherichia coli andBacillus subtilis

Summary Small plasmids ofClostridium acetobutylicum and related strains were isolated and studied. Their restriction maps were established and different hybrid plasmids were constructed by ligation with plasmid pHV33.     

Variants of the anti-Müllerian hormone gene in a compound heterozygote with the persistent Müllerian duct syndrome and his family

Summary The human genome contains a large number of interspersed simple repeat sequences that are variable in length and can therefore serve as highly informative, polymorphic markers. Typing procedures include conventional multilocus and single locus probing, and polymerase chain reaction aided analysis. We have identified simple sequences in a cosmid clone stemming from the human Y chromosome and consisting of (gata)_n repeats. We have compared these with two equivalent simple repeat loci from chromosome 12. After amplifying the tandemly repeated motifs, we detected between four and eight different alleles at each of the three loci. Codominant inheritance of the alleles was established in family studies and the informativity of the simple repeat loci was determined by typing unrelated individuals. The polymorphisms are suitable for application in linkage studies, practical forensic case work, deficiency cases in paternity determination, and for studying ethnological questions. The mutational mechanisms that bring about changes in simple repeats located both on the autosomes and on the sex chromosomes, are discussed.Professor Dr. Otto Prokop (Humboldt-Universität Berlin) on the occasion of his 70th birthday     

Réactions observées chez l'Anguille maintenue dans un milieu privé d'électrolytes,en particulier au niveau du système hypothalamo-hypophysaire

Résumé 45 Anguilles sont maintenues (32 h. à 46 jours) en eau déminéralisée (désionisée ou distillée). On note un assombrissement de la pigmentation, une hypertrophie importante de la vésicule biliaire et des modifications du système hypothalamo-hypophysaire.Dans la pars distalis rostrale, les cellules à prolactine subissent une régression, ne semblant plus élaborer de granulations. Les cellules corticotropes sont faiblement stimulées, partiellement dégranulées, en accord avec la légère activation de l'interrénal. Les cellules thyréotropes apparaissent souvent peu actives après 46 jours; cependant, l'examen préliminaire des thyroïdes ne montre pas d'hypoactivité. Dans la pars distalis proximale, les cellules gonadotropes ne sont pas modifiées; les cellules somatotropes sont stimulées: hypertrophie nucléaire et nucléolaire, développement de l'ergastoplasme, sans dégranulation complète. Leur rôle dans l'osmorégulation est discuté. Dans le lobe intermédiaire, les cellules du type 1, hématoxyline au plomb positives, prédominent chez les témoins; elles subissent une stimulation avec dégranulation partielle correspondant peut-être à l'assombrissement de la pigmentation. Le type 2, PAS positif, s'hypertrophie et s'hyperplasie rapidement en eau déminéralisée. Cette hyperactivité indiquerait un rôle dans l'osmorégulation. Le neuroséorétat s'accumule, puis tend à diminuer, la neurohypophyse étant de volume réduit. Le noyau préoptique paraît peu actif. L'hypothèse d'une faible utilisation des produits élaborés par l'axe hypothalamo-neurohypophysaire est envisagée. En plus de l'interrénal et des corpuscules de Stannius, l'hypothalamus et l'hypophyse interviennent donc dans la réponse de l'Anguille à une déminéralisation du milieu ambiant.

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Summary 45 male silver eels were kept from 32 hours to 46 days in demineralized (distilled or deionized) water. They show a darkening of the skin, a hypertrophy of the gall-bladder and some modifications of the hypothalamo-neuro-adenohypophysial system.In the rostral pars distalis, the prolactin cells regressed and appeared chromophobic. The corticotrophic cells are slightly stimulated and partly degranulated, in correlation with some activation of the interrenal, previously described. The thyrotrophic cells do not appear active at the end of the experiment, however the thyroid glands are not often inactive.In the proximal pars distalis, the gonadotrophic cells remain undifferentiated. The somatotrophic cells are strongly stimulated: a cellular, nuclear and nucleolar hyperactivity, without degranulation and a development of the ergastoplasm are observed. Their role in osmoregulation and metabolism of potassium is discussed.The pars intermedia is composed of two cell types: one of which is predominant, leadhematoxylin positive. It could elaborate the MSH (intermedin). In demineralized water, it is partly degranulated and progressively stimulated, perhaps in correlation with the darkening of the pigmentation. The other cell type is PAS positive, and not abundant in the control fish. In the treated fish, rapid hyperplasia and hypertrophy occur, with cytoplasmic degranulation and mitotic activity, so that it becomes predominant in this lobe after a month or more in demineralized water. Cytologic criteria indicate a great hyperactivity which seems to play a role in the processes of the osmoregulation; this hypothesis is discussed.The neurosecretory material tends to increase, as a storage, then to decrease in the neurohypophysis which is of a reduced volume. The preoptic nucleus does not appear active. In addition to the modifications of the interrenal and the corpuscles of Stannius previously described, the changes in the hypothalamus and the pituitary constitute evidence of their important role in the reaction of the eel to a demineralized environment.

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Ce travail a été réalisé avec la collaboration technique de Mademoiselle Jacqueline Olivereau, du C.N.R.S., que nous remercions bien vivement: elle nous a beaucoup aidée au cours de ces expériences, en particulier lors des changements quotidiens de l'eau distillée ou désionisée, et a réalisé toutes les préparations histologiques et les microphotographies illustrant cet article.     

Interaction between cells and elastin fibers: An ultrastructural and immunocytochemical study

Mesenchymal cells (fibroblasts, smooth muscle cells) and endothelial cells were shown to interact with elastin fibers. The strong adhesion of elastin fibers to these cells is mediated by a cell membrane complex with a major glycoprotein component of 120 kDa designated as elastonectin. This interaction was studied by transmission electron microscopy (TEM) and immunocytochemical techniques using antibodies raised against the elastin adhesive proteins. When fibroblasts and smooth muscle cells were cultured in presence of elastin fibers, TEM showed an adhesion mechanism that takes place over several sites along the plasma membrane of these cells. Endothelial cells showed a very close association with elastin, emitting “pseudopodia” that embody the fibers. TEM, indirect immunofluorescence, immunoperoxidase, and confocal microscopy showed the presence and localization of cell membrane components synthesized in large quantities when cells were incubated in presence of elastin. Cells without elastin fibers barely revealed the adhesive membrane complex. These results confirm and extend previous findings concerning the presence of an inducible cell membrane complex that mediates the adhesion of elastin fibers to these cell types. © 1994 Wiley-Liss, Inc.     

Ozone-induced microscopical changes and quantitative carbohydrate contents of hybrid poplar (Populus × euramericana)

Summary Cuttings of hybrid poplar (Populus × euramericana var. Dorskamp) were exposed to ozone (80 g/m³ from 2100 hours to 0700 hours, 180 g/m³ from 0700 hours to 2100 hours) for 3 months. Ozone reduced the starch content in leaves and stem bark, whereas starch granules accumulated in bundle sheath cells along small leaf veins. At the same time, sucrose and inositol content increased in the leaves. Mesophyll cells in the vicinity of the stomata were injured first, and droplet-like material appeared on their walls. In the sieve plates of fumigated trees, the pores showed a higher degree of narrowing than those of the control treatment. Cell collapse in the leaves was accompanied by water loss and an increase in air space. In the stems, the ozone treatment led to a reduced radial width, particularly in the xylem tissue. These results are discussed in relation to reduced or inhibited phloem loading and ozone-induced drought stress. The plants injured by ozone showed quite distinct patterns of metabolite responses as well as enzyme activities (PEP- and RubP-carboxylase) in the leaves from the top to the bottom. There were also remarkable differences in the reaction of sucrose and inositol between leaves and stem bark. Future research should therefore increasingly follow a whole-plant approach for a better understanding of complex plant reactions.     

Two genes present on a transposon-like structure in Lactococcus lactis are involved in a Clp-family proteolytic activity

The lactose-protease plasmid pUCL22 of Lactococcus lactis subsp. lactis strain CNRZ270 contained two inverted copies of IS 1076 flanking a region of 3.7 kb. This internal region was sequenced and found to contain two large open reading frames, ORF1 and ORFP in opposite orientations. ORF1 consists of 2289 bp; the deduced 763-amino-acid sequence is similar to the ATPases of the ClpA family. It contains two well-conserved consensus ATP-binding sites. It was named ClpL. ORFP consists of 930 bp encoding a protein of 310 amino acids. No similarity with any known protein was found in GenBank data for ORFP. Increased ATP-dependent proteolytic activity was detected in extracts from Escherichia coli cells expressing the clpL and ORFP genes.