Isolation and structural analysis of the phospho-beta-galactosidase gene from Streptococcus lactis Z268

A 4.4-kb XhoI fragment of Streptococcus lactis L13 (Z268) lactose plasmid pUCL13, containing the beta-D-phosphogalactoside galactohydrolase (P-beta Gal; EC 3.2.1.85)-coding gene has been cloned in Escherichia coli. Further subcloning and deletion of this fragment allowed localization of the P-beta Gal-coding gene (pbg) on a minimal 1.8-kb segment. Expression of P-beta Gal activity was constitutive and was not regulated by glucose in E. coli. The presence of P-beta Gal activity was correlated with the production of a 56.5-kDa protein in E. coli minicells. The nucleotide sequence of the cloned gene was determined and potential promoter structural elements were identified.     

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.     

Differentiation and structural decline in the leaves and bark of birch (Betula pendula) under low ozone concentrations

Summary Leaf and bark structure of a birch clone (Betula pendula Roth) continuously exposed to charcoal-filtered air or charcoal-filtered air plus ozone (0.05, 0.075, 0.1 l 1^-1) was investigated throughout one growing season. Increasing ozone dose influenced leaf differentiation by reducing leaf area and increasing inner leaf air space, density of cells developing into stomata, scales and hairs. When approximately the same ozone dose had been reached, macroscopical and microscopical symptoms appeared irrespective of the ozone concentration used during treatment. Structural decline began in mesophyll cells around stomatal cavities (droplet-like exudates on the cell walls), continued with disintegration of the cytoplasma and ended in cell collapse. Epidermal cells showed shrinkage of the mucilaginous layer (related to water loss). Their collapse marked the final stage of leaf decline. When subsidiary cells collapsed, guard cells passively opened for a transitory period before collapsing and closing. With increasing ozone dose starch remained accumulated along the small leaf veins and in guard cells. IIK-positive grains were formed in the epidermal cells. This contrasted with the senescent leaves, where starch was entirely retranslocated. Injury symptoms in stem and petiole proceeded from the epidermis to the cambium. Reduced tissue area indicated reduced cambial activity. In plants grown in filtered air and transferred into ozone on 20 August, injury symptoms developed faster than in leaves formed in the presence of ozone. Results are discussed with regard to O₃-caused acclimation and injury mechanisms.