Cytophilic binding of IgE to the macrophage. III. Involvement of cyclic GMP and calcium in macrophage activation by dimeric or aggregated rat myeloma IgE

Discharge of lysosomal enzymes, measured by release of β-glucuronidase, was studied in uninduced rat macrophages stimulated in vitro with rat monoclonal IgE (IR 162) in different states of aggregation. Monomeric IgE showed negligible activity, while dimeric and aggregated IgE were shown to induce a rapid and selective release of β-glucuronidase as well as new synthesis of the enzyme, without change in the cytoplasmic marker, leucine aminopeptidase. Lysosomal enzyme release is related to the dose of dimeric IgE, becoming maximal above 2.5 μg/ml. β-Glucuronidase release from macrophages by dimers is competitively inhibited by monomeric IgE but only at high ratios, approximately 100-fold greater than those needed to block mast cell release of the same enzyme. The difference in inhibitability is consistent with the difference in binding affinity of macrophages and mast cells for monomeric IgE. This observation rules out the participation of the few remaining mast cells contained in the macrophage monolayer in β-glucuronidase release. Dimeric or aggregated IgE produced a rise in cyclic GMP coincident with the peak fixation of IgE by macrophages. Elevation of cyclic GMP by pharmacological means also stimulated β-glucuronidase release and new synthesis, as well as enhancing the effect on these of aggregated IgE. Enzyme release by IgE did not occur in the absence of extracellular calcium. We conclude that IgE, which has been cross-linked to form dimers before binding to specific macrophage receptors, triggers the cell and that cyclic GMP (and perhaps calcium) modulates the early step of macrophage activation.     

Changes in calmodulin level after fertilization and during first cleavage in the egg of the urodelan amphibian Pleurodeles waltlii

We report three significant calmodulin rises related to Pleurodeles waltlii egg fertilization and following developmental events. These elevations are correlated to the major obvious Ca2+-dependent events: Na+-H+ exchange, activation of NAD kinase, triggering of cortical reaction, resumption of meiotic division II, initiation of DNA synthesis and regulation of cell division. Therefore, it is suggested that alterations in calmodulin level in fertilized egg may be part of the Ca2+-dependent regulatory mechanisms which turn on metabolisms, initiate development and govern cell cleavages.     

Mechanisms of cisplatin (cis-diamminodichloroplatinum II)-induced cytotoxicity and genotoxicity in yeast

The antitumor drug, cisplatin (cis- diamminodichloroplatinum II), dissolved in both water and phosphate-buffered saline, was studied for its genotoxic and cytotoxic effects in the yeast, Saccharomyces cerevisiae. The results showed that the drug was both recombinagenic and mutagenic in the wild-type diploid strain D7. It was observed that both cytotoxicity and genotoxicity were greatly reduced when cisplatin was dissolved in phosphate-buffered saline compared to the aqueous solution. Cell survival analyses showed that the diploid strain (D7 rad 3), deficient in excision of UV-induced pyrimidine dimers or similar adducts, was hypersensitive to cisplatin. Another diploid strain (rad 52/rad 52), blocked in the repair of DNA double-strand breaks and recombination was also hypersensitive to the drug. Mitotic gene conversion was not observed in the rad 52/rad 52 diploid after the drug treatments, while it was reduced in the excision -deficient strain. Reverse mutations occurred in the excision-deficient strain (D7 rad 3), even at low doses of cisplatin. These results are discussed in relation to the possible mechanisms of cisplatin-induced cell death and genotoxicity.     

Etude de la reponse à un stress hydrique de quelques varietés de riz pluvial et de riz irrigué

Résumé La transpiration de plants de riz cultivés sur sol en chambre de culture, est suivie en continu pendant une séquence déssèchement-irrigation. Les cycles jouraliers de transpiration sont présentés avant et pendant le stress hydrique. Quatre variétés montrent une augmentation de la transpiration nocturne qui disparait lors du stress hydrique. Il apparait que la régulation stomatique est indépendante du potentiel hydrique du sol jusqu'à une valeur seuil au-delà de laquelle la baisse de transpiration est proportionnelle à la baisse du potentiel hydrique. Cette valuer seuil est plus basse pour les variétés de type irrigué.

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Water stress response for some cultivars of upland- and lowland riceI. Effects on transpiration

Summary The transpiration of rice seedlings grown on soil in a growth chamber was observed during a soil drying/rewetting sequence. The diurnal cycles of transpiration are shown before and during the water stress period. Four cultivars showed an increase of transpiration during the night. This increase disappeared during the water stress period. The stomatal regulation appeared not to depend on the soil water potential until a certain value. Below this soil-water threshold, the decrease of transpiration was proportion to the decrease of water potential. This threshold value is lower for the rain-fed cultivars than for the irrigated cultivars.

     

The Oldowan site of Muhkai II,layer 80 (northeastern Caucasus): Spatial structure and cultural and chronological attribution of the lithic assemblage

In 2004–2006 a group of Lower Palaeolithic sites was discovered in the northeastern Caucasus: Ainikab I–VI, Gegalashur I–III and Muhkai I–II. Since then, they have been the subject of comprehensive scientific investigations. One site which is undergoing active research is the multilayered site of Muhkai II. Multiple cultural layers at the site have been found in a 73 m thick sequence of Early Pleistocene sediments. The geological age of the layers encompasses the interval 2.1–0.8 million years ago, or the majority of the Early Pleistocene. Layer 80 of Muhkai II is located in the central part of the section at a depth of −33.6 to −34.0 m. Its significance lies in the fact that the site contains two cultural layers–the upper and the lower (main)–that are preserved in situ or have been subject to minimal fluvial processes. The finds consist of lithic artefacts and osseous faunal remains. According to field observations and microstratigraphic analyses, the cultural layers can be characterised as the ancient surfaces of an occupation area. Two stages of occupation can be defined in the lower cultural layer. Layer 80 of Muhkai II was a periodically visited location at the banks of a waterbody, where the acquisition and butchery of large mammals took place. The faunal collection contains 301 bones, deriving from four carnivorous and six herbivorous species of mammals. The total lithic collection contains 1094 finds. According to typological and technological criteria the lithic assemblage relates to the Oldowan and has analogies with Oldowan sites in Africa (particularly with sites of the Olduvai Gorge as well as others). At the same time, some specifics of the lithic assemblage reflect the uniqueness of the site and its functional type. Layer 80 of the Muhkai II site is estimated to date to within the chronological interval ∼2.1–1.7 mya.     

Potassium and veratrine-stimulated l-[3H]cysteine sulfinate and l-[3H]glutamate release from rat brain slices

The release of l-[³H]cysteine sulfinic acid, l-[³H]glutamatic acid and [³H]GABA from preloaded slices of various rat brain regions in response to either 30 mM K⁺ or veratrin was investigated. All these aminoacids were released by both depolarizing agents, which did not produce any changes in the spontaneous efflux of [³H]lysine. The K⁺ stimulated cysteine sulfinate release from superfused slices was found partly Ca²⁺-dependent in the subiculum, and mainly Ca²⁺-independent in the hippocampus whereas the K⁺-elicited glutamate release was partly Ca²⁺-dependent in both regions. The veratrine-induced release of both cysteine sulfinate and glutamate was blocked by verapamil in a dose-dependent way, although a small verapamil concentration independent release remained. The release pattern of both amino acids was heterogeneous, but roughly correlated among brain regions, except in the subiculum and hypothalamus.These findings demonstrate the releasability of both substances from various brain regions and suggest that those releases occur from different pools, being probably mainly of neuronal origin. They give further evidence that cysteine sulfinate as well as glutamate may serve a neurotransmitter role in the CNS.     

Trace metal requirements in total parenteral nutrition (TPN). 5. Formation constants for the copper(II)--histidine ternary complexes with threonine, lysine, glycine, phenylalanine, valine, and cystine, and discussion of their implications regarding the copper distribution in blood plasma during TPN and the evaluation of the daily dose of copper

Specific metal deficiencies have been reported to affect patients receiving total parenteral nutrition (TPN). Our previous studies on the topic were devoted to the computer-based interpretation of the extra urinary excretion of zinc; a theoretical approach was also proposed, with a view to compensating for the extra losses of this metal. Similarly, the present work deals with the problem of TPN-induced copper deficiency and its remedy. As is the case for zinc, the TPN-induced excretion of copper clearly stems from the relative mobilization of the plasma protein-bound pool of this metal into its diffusable low-molecular-weight fraction; this phenomenon being due to the competitive complexation of copper by the amino acids of the nutritive solution. The computer simulation of this effect thus required that first the equilibrium constants be experimentally determined for the main complexes of copper that might form in the solution as well as in plasma during the infusion. Accordingly, complex formation in the copper-histidine ternary systems with threonine, lysine, glycine, phenylalanine, valine, and cystine was investigated by potentiometry at 37 degrees C in NaCIO4 0.15 mol X dm-3. The implications of the results obtained are discussed with regard to the interpretation of the copper excretion and the estimation of the desirable daily dose of this metal for the TPN mixture under consideration.     

The Vallonnet cave on the northern Mediterranean border: A record of one of the oldest human presences in Europe

Prehistoric sites testifying to human presence older than one million years in Europe are rare, and in the current state of knowledge, the oldest of them have been dated to around 1.4–1.5 Ma. The Vallonnet cave at Roquebrune-Cap-Martin in the Alpes-Maritimes, on the Mediterranean border, is one of the oldest sites in France to have yielded evidence of human activity: a lithic assemblage of about a hundred pieces and traces of butchery on bones of an Epivillafranchian fauna. The archaeological levels of this small cave were recently dated between 1.1 and 1.2 Ma by U-Pb correlated with paleomagnetic data. The site was occupied alternately by large carnivores that used it as a den or a lair, and by hominins that stayed there briefly in bivouac. The lithic remains are mainly percussion tools, shaped pebbles, flakes and cores, whose raw materials are local, or even semi-local, and on the whole not very diversified with mainly limestone, and to a lesser extent sandstone, quartzite, flint and quartz. This assemblage is attributed to a Mode 1 technology (Oldowayen), among which macro-tools (hammerstones, shaped and fractured pebbles) are found alongside rarer elements resulting from debitage operating chains aimed at producing sharp-edged flakes, very rarely retouched. The bipolar-on-anvil flaking technique could be identified from the characteristics of some artifacts. Several refitting flakes on shaped pebbles or percussion tools attest to knapping and percussion activities in the cave. Hominins consumed the remains of large herbivore carcasses, as attested by the presence of cutting and fracturing marks on some bones. The presence of a freshwater source in the immediate vicinity, and the knapping and butchering activities here therefore document the subsistence behavior of Lower Pleistocene human groups, certainly in competition with the carnivores present.     

The Late Pleistocene Orangutan from Tham Prakai Phet: New discoveries

This paper describes the collection of isolated orangutan fossil teeth identified in the newly excavated material from Tham Prakai Phet, a site located in the Chaiyaphum Province in northeast Thailand. The collection is composed of 18 isolated teeth belonging to Pongo. The morphology of the upper and lower teeth is similar to that of fossil and extant orangutans from mainland Indochina and Indonesia. Only the wrinkles on the occlusal surface are less pronounced and sometimes simpler than extant orangutans. The dimensions of the teeth fall in the range of variation of fossil and extant specimens, but the distribution of the crown areas of the Tham Prakai Phet specimens fall above the mean value observed for extant orangutans. This new collection of continental orangutans confirms the persistence of this taxa in this part of Thailand up to the late Pleistocene, and provides new data useful for understanding the evolution of this hominoid and advance in the reconstitution of the evolutionary lineage of Pongo. The size of the sample from Tham Prakai Phet is not sufficient to determine an accurate taxonomic attribution; pending the increase of the current sample, we attribute the material to Pongo sp. (Pongo aff. weidenreichi).