Expression of platelet glycoprotein Ib alpha in HEL cells

We have previously shown that platelet glycoprotein Ib is expressed in a minority of cells of the human leukemic cell line HEL (Tabilio, A., Rosa, J. P., Testa, U., Kieffer, N., Nurden, A. T., Del Canizo, M. C., Breton-Gorius, J., and Vainchenker, W. (1984) EMBO J. 3, 453-459). In this report, we have selected a stable HEL subclone with increased expression of glycoprotein (GP) Ib as assessed by 6 different monoclonal antibodies in order to investigate the biochemical characteristics of this glycoprotein. A single polypeptide chain of apparent Mr = 60,000 was precipitated under reducing and nonreducing conditions by a specific polyclonal anti-platelet glycocalicin antibody and two anti-GPIb alpha monoclonal antibodies (AN51 and AP1), both from surface-labeled and metabolically labeled HEL cells. We were unable to demonstrate the presence of a polypeptide corresponding to the beta subunit of GPIb or GPIX which is closely associated with GPIb. Competitive immunoprecipitation performed in the presence of an excess amount of cold platelet glycocalicin completely displaced the Mr = 60,000 polypeptide. Synthesis of N-linked oligosaccharide chains on this Mr = 60,000 polypeptide was inhibited by the antibiotic tunicamycin, and a shift of the apparent Mr from 60,000 to 48,000 was observed. O-Linked oligosaccharide chains identical to platelet GPIb hexasaccharides were deficient or incomplete since no peanut agglutinin binding to the Mr = 60,000 polypeptide was observed after neuraminidase treatment of HEL cells. Thus, our results provide evidence that the Mr = 60,000 polypeptide expressed on the surface membrane of HEL cells is closely related to platelet GPIb and corresponds to an incompletely or abnormally O-glycosylated GPIb alpha subunit.     

Cladocera from the Sudan: Red Sea Hills,Jebel Marra and valley of the main Nile

Twenty species of Cladocera are reported from the Nile, where lacustrine species dominate, and from Jebel Marra and the Red Sea Hills, where chydorids dominate. The community found in the Red Sea Hills is more typically desertic than that of Jebel Marra, which appears closely related to the fauna of the West and Central African Sahel.     

Ouabain-resistant Na+, K+ transport system in mouse NIH 3T3 cells

Summary It is shown that the ouabain-resistant (OR) furosemide-sensitive K⁺(Rb⁺) transport system performs a net efflux of K⁺ in growing mouse 3T3 cells. This conclusion is based on the finding that under the same assay conditions the furosemidesensitive K⁺(Rb⁺) efflux was found to be two- to threefold higher than the ouabain-resistant furosemide-sensitive K⁺(Rb⁺) influx. The oubain-resistant furosemide-sensitive influxes of both²²Na and⁸⁶Rb appear to be Cl^– dependent, and the data are consistent with coupled unidirectional furosemide-sensitive influxes of Na⁺, K⁺ and Cl^– with a ratio of 1 1 2. However, the net efflux of K⁺ performed by this transport system cannot be coupled to a ouabain-resistant net efflux of Na⁺ since the unidirectional ouabain-resistant efflux of Na⁺ was found to be negligible under physiological conditions. This latter conclusion was based on the fact that practically all the Na⁺ efflux appears to be ouabainsensitive and sufficient to balance the Na⁺ influx under such steady-state conditions. Therefore, it is suggested that the ouabain-resistant furosemide-sensitive transport system in growing cells performs a facilitated diffusion of K⁺ and Na⁺, driven by their respective concentration gradients: a net K⁺ efflux and a net Na⁺ influx.     

A revision of the Scapholeberinae (Crustacea: Cladocera)

The group of hyponeustonic daphniid cladocera previously known under the generic name Scapholeberis is raised to the rank of a subfamily (Scapholeberinae) and contains two genera, Megafenestra n.gen. (2 species), and Scapholeberis s.s. (7 species and one subspecies). The characters upon which this revision is based are: structure of the rostrum, structure of the first antennae, structure of trunk limbs 1, 2, and 5, presence and nature of headpore(s), structure of the ventral rim of the valves, armature of the distal rim of the valves, structure of the postabdomen and its end-claws. Males were examined in all but two species, and proved to be more primitive than females and much less diagnostic than in the Chydoridae. It also appeared that the shape and armature of the postabdomen are less important taxonomical tools than heretofore supposed. In more than half of the species, it is of generalised shape and hardly usable beyond the species-group level. The same, although less drastically, holds true for the P1 of males. Of greatest diagnostic value at the species level are the shape of the rostrum and the armature of the valve margins. A phylogeny of the subfamily is proposed, with Megafenestra as the more primitive genus, closely allied to Ceriodaphnia, and within Scapholeberis, S. mucronata as the most apomorphic species. In biogeographical respect, no species is cosmopolitan, although their ranges may be of continental dimensions. Species and populations appear to concentrate in the temperate and continental climate belts of the northern hemisphere, but more research in the southern hemisphere is needed. A key for the identification of all species is given.     

Pseudophillipsia azzouzi nov. sp. Trilobite griffithididé Permien du Djebel Tebaga (Tunisie)

Pseudophillipsia azzouzi nov. sp., found by L. Memmi and J. David in the Dolomies superieures Series of the Djebel Tebaga, takes part of the Ps. sumatrensis-Group. Its stratigraphical position in the Kazanian-Pamirian boundary is in accordance with the global distribution of that Group. The tunisian species, characterized by its ornamentation (particularly of the pygidium), is also remarkable by its large size, twice that of the type-species.     

Flore levuriforme intestinale du babouin,Papio papio (Desm.)

Résumé Chez 44 Babouins,Papio papio (Desm.), appartenant à la collection du Parc zoologique de Paris, distingués en trois groupes, en fonction de l'âge, nous avons pratiqué 101 prélèvements aux niveaux suivants du tube digestif: intestin grêle gros intestin et rectum.C'est chez les animaux les plus âgés que nous avons obtenu les valeurs les plus élevées pour les deux critères étudiés, le pourcentage de positivité et la richesse spécifique des prélèvements et ce, aussi bien en ce qui concerne l'ensemble des levures identifiées que pour les seuls constituants de la flore probable. La fréquence de ces champignons aux divers étages du tube digestif, ainsi que l'incidence saisonnière sur les isolements ont été abordés.

---

In 44 Baboons,Papio papio (Desm.), of the Zoological Park of Paris, 101 samples have been taken at three levels of the alimentary tract: small intestine, large intestine and rectum. Three groups of subjects have been recognized according to age. The yeasts or the yeast-like flora, have been found with maximum of frequency and diversity in the oldest animals. The variations of the isolation in the three levels of this Mammal's gut and the seasonal influence have been discussed.

     

Calorimetric measurement of free energy utilization by Nitrosomonas and Nitrobacter

Summary Calorimetric estimates of the utilization efficiency of the free-energy derived from substrate oxidation by cell suspensions of two nitrifying bacteria, Nitrosomonas and Nitrobacter, provided two ranges of values: 11 to 27% and 15 to 51%, respectively. About 15 to 30% of the utilized free-energy is used for driving endergonic reactions other than CO₂ fixation, probably the synthesis of polyphosphates.The molar heat of substrate oxidation does not seem to be influenced by the age of cells harvested during growth or by the length of the incubation period during which cells have been kept in a buffer suspension in a starved condition. The loss of respiratory activity measured either by oxygen uptake or heat evolution in the presence of the specific substrate, nitrite or ammonium, decreases according to kinetics which are influenced by the aerobiosis of the suspension. The viability of the starved cells decreases in a way which is similar to that of the respiratory activity. It seemed impossible to obtain cells which had lost their viability but kept the ability to oxidize their substrate.Two inhibitors of the respiratory chain, quinacrine and cyanide, are without effect on the molar heat of substrate oxidation and consequently on the free-energy utilization efficiency. 2.4 dinitrophenol did decrease the rate of heat evolution during substrate oxidation at concentrations at which the rate of oxygen uptake was not depressed, with the consequences that free-energy efficiency was apparently increased.     

Developmental changes in high-affinity uptake of GABA by cultured neurons

High-affinity uptake of [³H]-aminobutyric acid (GABA) was studied in cultures of neonatal rat cortical neurons grown on pre-formed monolayers of non-neuronal (glial) cells. Both the maximum rate (V _max) and, to a smaller extent, theK _m of [³H]GABA uptake increased with time. In addition, in parallel with these changes, 2,4-diaminobutyric acid and cis-3-aminocyclohexane-1-carboxylic acid (ACHC), compounds which are considered typical substrate/inhibitors of GABA uptake in neurons, became progressively stronger inhibitors of [³H]GABA uptake. Consequently, the present results may mean that the studies using uptake, of [³H]GABA, [³H]ACHC, or [³H]DABA as a specific marker for GABAergic neurons differentiating during the ontogenetic development of the central nervous system may have to be interpreted with caution.     

Seasonal incidence of Ixodes ricinus ticks (Acari: ixodidae) on rodents in western France

Data collected from a longitudinal survey carried out over 2 years on four farms in western France were used to assess the incidence and infestation of Ixodes ricinus on rodents. Once a month, on each farm, 25 Sherman live traps were set in hedges bordering selected pastures. A total of 799 micromammals were examined, including Apodemus sylvaticus, Clethrionomys glareolus, Microtus agrestis, Microtus arvalis, and Crocidura spp. Larvae and nymphs of I. ricinus were found. Small numbers of Ixodes (Exopalpiger) trianguliceps were also recovered from each farm. The mean infestation rate of the I. ricinus larvae (1.6–5.9) among all animals examined varied between farms Most animals were infested by only a single tick, but one M. agrestis harboured 43 I. ricinus larvae. Larvae or nymphs were found throughout the year, with peaks from March to October.     

<Emphasis Type="Italic">Alona alsafadii</Emphasis> n. sp. from Yemen,a primitive,groundwater-dwelling member of the <Emphasis Type="Italic">A. karua</Emphasis>-group

The effect of algae on the production of musty-smelling compounds by actinomycetes was studied. Streptomyces spp., causing intensive musty odor, were isolated from hypertrophic Lake Kasumigaura and cultured in association with algae from the same lake. Isolate E and I effectively utilized the cyanobacteria, Microcystis aeruginosa and Anabaena spiroides, and the diatom, Synedra acus, as a carbon source and produced a musty-smelling 2-methylisoborneol in the shaken sediment cultures. High populations of algae and actinomycetes, and aerobic condition in the sediment seem responsible for the occurrence of musty odor in Lake Kasumigaura.