Characterization of DNAs fromCoprinus lagopus andMucor azygospora

Resumé Les rapports G+C des ADN deCoprinus lagopus etMucor azygospora ont été étudiés. Le profil de fusion indique que l'ADN duC. lagopus est composé de deux fractions, une principale (90%) de rapport G+C 52 moles pourcent, une mineure (10%) de G+C 32 moles pourcent. Par contre l'ADN deM. azygospora contient une fraction unique de G+C 38 moles pourcent. L'étude de la cinétique de réassociation DNA:DNA montre que la dimension génomique («genome size») deC. lagopus est de 2×10¹² et qu'il y a moin de 10% de DNA à séquences répétées de nucléotides.

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This research was supported in part by the U.S. Atomic Energy Commission Contract No. AT (40-1) 4182 and the Research Corporation, New York, to S.K.D. We are grateful to ProfessorG. Turian, University of Geneva, for making possibleM. Ojha's participation in this research.     

Activation and specificity of alkaline phosphatase of a mineralizing collagen-rich system

Summary Alkaline phosphatase from tibia tendon ofMeleagris gallopavo L. was highly purified. The enzyme activation by different ions was measured. Mg²⁺ showed a high activation with a broader spectrum of phosphomonoester hydrolization. The in vivo Mg²⁺ concentration was an optimum for in vitro activation.Dedicated to Prof. Dr. G. Pfefferkorn on the occasion of his 65^th birthday.We thank Deutsche Forschungsgemeinschaft for support.     

The presence of RNA of the A–U type in citrate nuclei isolated from rabbit liver cells

Zusammenfassung Die in 5% iger Zitronensäure isolierten Kaninchenleberkerne enthalten eine minimale Fraktion von RNS, die sich durch ihren Gehalt an Basen der DNS annähert (A+U/G+C>1). Diese RNS wird während der Extraktion mit dem 6% igen Natrium-p-Amino-salicylat und dem Phenol zusammen mit der DNS und RNS vom G+C-Typ gewonnen.     

Overexpression of HAb18G/CD147 promotes invasion and metastasis via α3β1 integrin mediated FAK-paxillin and FAK-PI3K-Ca2+ pathways

Mechanism of HAb18G/CD147 underlying the metastasis process of human hepatoma cells has not been determined. In the present study, we found that integrin α3β1 colocalizes with HAb18G/CD147 in human 7721 hepatoma cells. The enhancing effect of HAb18G/CD147 on adhesion, invasion capacities and matrix metalloproteinases (MMPs) secretion was decreased by integrin α3β1 antibodies (p<0.01). The expressions of integrin downstream molecules including focal adhesion kinase (FAK), phospho-FAK (p-FAK), paxillin, and phospho-paxillin (p-paxillin) were increased in human hepatoma cells overexpressing HAb18G/CD147. Deletion of HAb18G/CD147 reduces the quantity of focal adhesions and rearranges cytoskeleton. Wortmannin and LY294002, specific phosphatidylinositol kinase (PI3K) inhibitors, reversed the effect of HAb18G/CD147 on the regulation of intracellular Ca²⁺ mobilization, significantly reducing cell adhesion, invasion and MMPs secretion potential (p<0.01). Together, these results suggest that HAb18G/CD147 enhances the invasion and metastatic potentials of human hepatoma cells via integrin α3β1-mediated FAK-paxillin and FAKPI3K-Ca²⁺ signal pathways. Received 5 June 2008; received after revision 16 July 2008; accepted 23 July 2008     

Aspects biochimiques des herbicides à base de triazines

Summary The triazine herbicides are potent inhibitors of theHill reaction, resembling the phenylureas, acylanilides and carbamates. The inhibition of the photosynthesis by the triazines is the most obvious explanation for their mode of action in plant metabolism. Besides this there are also effects on light independent reactions where the effective concentrations are higher than those inhibiting the photosynthesis. Particularly, a positive influence of the triazines on the uptake of the nutrients by the roots was noted. Changes in the nitrogen metabolism of the plants, due to increased uptake of nitrate from the medium, result in a higher content of organic nitrogen in the plants.Several enzyme systems in plants and in micro-organisms are influenced by the triazine herbicides. Until now, the mechanism of action has not been elucidated.Concerning the phenomenon of the selectivity of the triazine herbicides, several factors may be responsible. The different abilities of the plant species to metabolize the herbicide and to translocate it to the active centres in the cells are significant from the biochemical point of view.

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Une partie de ce travail a été présentée lors de la 463^e séance de la Biochemical Society, Aberystwyth, septembre 1966.P. W. Müller, Biochem. J.101, 1P. (1966).Nous tenons à exprimer nos remerciements àR. Truan qui a bien voulu se charger de la version française ainsi qu'àG. Dupuis pour sa participation à la mise au point du manuscrit.     

RTA2 is involved in calcineurin-mediated azole resistance and sphingoid long-chain base release in Candida albicans

The calcineurin pathway has been reported to be essential for the development of azole resistance in Candida albicans. The depletion or ectopic over-expression of RTA2 increased or decreased susceptibility of C. albicans to azoles, respectively. CaCl₂- induced activation of the calcineurin pathway in wildtype C. albicans promoted resistance to azoles, while the Ca ²⁺ chelator (EGTA), calcineurin inhibitors (FK506 and cyclosporin A) and the deletion of RTA2 blocked the resistance-promoting effects of CaCl₂. Furthermore, we found that RTA2 was up-regulated in a calcineurin-dependent manner. The depletion of RTA2 also made the cell membrane of C. albicans liable to be destroyed by azoles and RTA2 over-expression attenuated the destroying effects. Finally, the disruption of RTA2 caused an increased accumulation of dihydrosphingosine (DHS), one of the two sphingolipid long-chain bases, by decreasing release of DHS. In conclusion, our findings suggest that RTA2 is involved in calcineurin-mediated azole resistance and sphingoid long-chain base release in C. albicans. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 14 July 2008; received after revision 29 August 2008; accepted 16 September 2008     

XO type of sex mechanism in earwigs (Dermaptera)

Summary The diploid chromosome complement inAllodahlia macropyga (Westwood) is 14+XO- and 14+XX- This is the first record in Dermaptera, of a XO male-determining mechanism.The authors express their sincere thanks to Prof. G. P. Sharma, Department of Zoology, Panjab University, Chandigarh, for providing research facililies.     

Inhibition of Ca2+-induced noradrenaline release from central noradrenergic neurons by morphine

Summary Morphine inhibited the noradrenaline release from slices of rat brain cortex induced by introduction of Ca²⁺ ions after superfusion with Ca²⁺-free, K⁺-rich solution. The degree of inhibition was inversely related to the Ca²⁺ concentration used for stimulation.Acknowledgment. We thank Mrs G. Thielecke and Miss G. Werthmann for technical assistance.     

Thermische Denaturierung von Kaltblüter-Enzymproteinen

Summary The temperature, which leads to 50% reduction of catalytic activity by heat denaturation, has been determined for 8 different enzymes from cod muscle, as being in the range between 30 and 52°C. Therefore, there are no indications of a generally different heat resistance of enzymes from cold-blooded animals as compared with those from warm-blooded animals. The same conclusion is derived from calculations ofQ ₁₀-values, measured between +37 and – 37°C for cathepsin and glycylglycine dipeptidase.

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Die Untersuchungen wurden dankenswerterweise durch eine Beihilfe des Bundeswirtschaftsministeriums Bonn unterstützt. HerrnDegener, i. Fa. Hanseatische Hochseefischerei A.G., Bremerhaven-F., verdanken wir das Untersuchungsmaterial.     

A schiff base of cycloserine

Zusammenfassung Vond-Cycloserin ist die erste Schiffsche Base isoliert und charakterisiert worden. Bei Erhitzen in Äthylalkohol unterbleibt die Umlagerung in einen Cycloserindimerenabkömmling und ergibt Racemisierung. Es wird gefolgert, dass Aldehyde nicht auf das Stickstoffatom des Isoxazolidons reagieren und dass Dimerisation von Cycloserinnicht für die Reaktion mit Aldehyden erforderlich ist.

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Cycloserine I.     

Heterogeneity of HeLa cell DNA as evidenced by CsCl density gradient centrifugation

Summary HeLa cell DNA was analyzed through CsCl density gradient centrifugation and thermal denaturation. Neutral centrifugation without ionic treatment allowed the resolution of a main peak with density 1.699 g/ml and of 3 satellites DNAs with densities 1.683, 1.710 and 1.720. First derivatives of melting curves showed the presence of 4 DNA families, whose G+C content calculated from T_m values corresponded almost exactly to the G+C content expected from the previously densities. The extraction method seems particularly suitable for quantitative separation of DNA classes.     

Heterochromatin characterization and distribution in the chromosomes of two populations ofIdotea baltica basteri Audouin, 1826 (Isopoda,Valvifera)

Two mediterranean populations ofIdotea baltica basteri from Messina and Naples showed a set of chromosomes composed by 58 all-biarmed chromosomes. The heterochromatin was located in the pericentromeric region of the chromosomes, and its composition appeared heterogeneous. In fact, not all the homologs showed heterochromatin resistant to digestion with three restriction enzymes (Alu I, Hae III and Sau 3A). Moreover, the two populations showed polymorphism in a band of G+C-rich telomeric heterochromatin, which was present only in the population from Messina. It is hypothesized that chromosomal polymorphism might reflect the geographical isolation of the two populations. It is also suggested that a process of diversification is taking place.     

Anti-bovineβ-lactoglobulin antibodies react with a human lactoferrin fragment and bovineβ-lactoglobulin present in human milk

Human milk samples react against anti-bovine-lactoglobulin rabbit antibodies, as measured by a competitive radioimmunoassay. Immunoreactivity was positive even in milk from mothers consuming a diet free of cow's milk. An increase with a diet rich in cow's milk proteins was detected by immunoelectrophoresis. The human milk fraction cross-reacting with anti-bovine-lactoglobulin antibodies corresponds to the 20 kDa fragment from the N-terminal end of human lactoferrin. Three regions of this fragment exhibit sequence homology with a sequence contained in cow's-lactoglobulin (between residues 124 and 141).     

Cytopathological effects of aristolochic acid on male houseflies causing sterility

Summary Feeding male houseflies with 0.075% aristolochic acid obtained from the plants of the genusAristolochia induced sterility. High condensation of chromosomes, and breakages, have been shown to be responsible for sterility. When onion roots were exposed to aristolochic acid similar chromosomal aberrations were noticed in cells at the tip.Authors are thankful to Prof. Dr G. Rücker (Universität Bonn) for a generous gift of aristolochic acid.     

Spontaneous occurrence of aneuploidy in somatic cells ofRana tigrina (Ranidae: Anura)

Zusammenfassung Es wurde Aneuploidie bis zu drei Chromosomen in den männlichen Körperzellen vonRana tigrina (Ranidae: Anura: Amphibia) beobachtet. Die Variationen betreffen:2n–3, 2n–2, 2n–1, 2n, 2n+1, 2n+2 und2n+3.

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Acknowledgments. My sincere thanks are due to Dr.S. P. Sharma, Zoology Department, for facilities; to Mr.R. K. Pillai and MissMadhu for technical assistance with preparations and Drs.K. K. Rishi andL. K. Vats for helpful suggestions.     

Chromosomes of the squirrelFunambulus palmarum bellaricus Wroughton

Summary The chromosome complement ofFunambulus palmarum bellaricus Wroughton (Mammalia-Rodentia-Sciuridae) has been studied for the first time, and the diploid number established to be 54, in contrast to the subspeciesF. p. palmarum which has 2n=46 chromosomes. The known karyotypes within the genusFunambulus are compared. We thank Prof. G. T. Tonapi for providing the laboratory facilities and the Zoological Survey of India, Western Regional Station, Pune for identifying the specimens.     

Interaction of polyamines or their precursors with the calcium-controlled secretion of peroxidase by sugarbeet cells

Summary Three polyamines tested (cadaverine, spermidine and spermine) and their 2 precursors (the amino acids arginine and ornithine) inhibit the Ca²⁺-mediated secretion of peroxidases by sugarbeet cells in suspension culture at concentrations ranging from 10^–15 to 10^–5M. In the absence of exogenous Ca²⁺, spermine added at higher concentrations mimics the activatory effect of Ca²⁺, the other polyamines being without effect.Supported by the Belgian FRFC (grant No. 2.9009.75 to T.G.) and the Swiss National Foundation for Scientific Research (grant No. 3.140-0.81 to C.P. and H.G.).     

Chromosome-breaking activity of extracts of the mushroomPaxillus involutus Fries ex Batsch

Summary Dry and presoaked seeds ofNigella damascena were treated with aqueous extracts of the mushroomPaxillus involutus. At the first mitosis after the onset of germination, metaphase chromosomes showed damage independent of the origin of the mushrooms. The damaging substance(s) is (are) thermostable. Except a few achromatic gaps, all the lesions observed are of the chromosome type, i.e. are induced at the pre-synthetic G1 stage.     

Effects of weak electromagnetic fields onPhysarum polycephalum: Mitotic delay in heterokaryons and decreased respiration

Summary Continuous exposure ofPhysarum polycephalum to a 75 Hz, 2.0 G, and 0.7 V/m electromagnetic field results in a depressed respiration rate and a lengthening of the mitotic cell cycle. If unexposedPhysarum are mixed with exposedPhysarum the onset of synchronous mitosis in the mixed culture is delayed, occurring at a time between those of the 2 parent cultures.Acknowledgment. This work was supported by the Naval Electronics Systems Command through an Office of Naval Research Contract and a grant from Parkside's Center for the Application of Computers.     

Quinone tanning in Agnatha

Summary The buccal teeth and notochordal sheath of the marine hagfish,Petromyzon marinus (L.) are phenolically tanned like the cuticle of insects and other arthropods.Acknowledgments. We are grateful to Dr Bill Lovejoy for generously supplyingP. marinus L. A.R.V. is thankful to Prof. R.G. Michael for encouragement.Previously called A. Sannasi.