A comparison between the photoreactivity of some furocoumarins with native DNA and their skin-photosensitizing activity

Riassunto È stata determinata la fotoreattività con DNA nativo di un gruppo di furocumarine per irradiazione a 365 nm. I valori ottenuti sono risultati in accordo con quelli di attività fotosensibilizzatrice cutanea posseduti dalle stesse sostanze.     

Blood histamine and response of spleen cells to phytohemagglutinins during moderate magnesium deficiency in the rat]

Blood histamine and spleen cell stimulation index by PHA were determined in either magnesium deficient or control Rats. Between the 10th and 17th days of diet (hyperemia and dermatosis period), histaminemia was significantly higher in deficient animals (485 ng/ml) than in control ones (112 ng/ml), but at the 32nd day it came back to normal values. The mean spleen cell stimulation index by PHA was depressed in deficient animals mainly between the 10th and 17th day of the deficiency; 33% of control mean value. A negative correlation is found between histamine level and stimulation index.     

Radicals and types: A critical comparison of the methodologies of Popper and Lakatos and their use in the reconstruction of some 19th century chemistry

Research programmes associated with two nineteenth-century chemical theories, Radical Theory and the Theory of Types are discussed. The purpose is to examine in a very general way how well the methodologies of Popper and Lakatos can account for the development of these programmes. The chemical discussion is prefaced by a critical comparison of certain aspects of the two above-mentioned philosophies.     

Studies on some enzymes of the toad (Bufo melanostictus) testis and their probable role at the time of fertilization

Summary Glycosidases like sialidase,-galactosidase, -L-fucosidase, N-acetyl hexosaminidase and proteases were detected in toad testis. Neuraminic acid aldolase activity was also detected. The enzyme activities were found to vary as production of spermatozoa varied. All enzymes, except N-acetyl glucosaminidase, were shown to decrease after injection of toad pituitary extract and they were also found to be absent from testis containing no spermatozoa. The glycosidases were found to act on toad oviduct jelly and they may therefore be involved in the degradation of the jelly after fertilization, into smaller bits, which may be utilized as nutrients by the fertilized zygote.Acknowledgment. We thank Prof. T.R. Ramaiah, Head of the Department of Biochemistry, University of Mysore, for his help. We also acknowledge the financial assistance of University Grants Commission to one of us (MS) and CSIR through a grant No. 9 (165)83/EMR-II to HSS. Please address all correspondence to H.S. Seshadri.     

Involvement of a surface concanavalin A-binding glycoprotein in the adhesion ofTrichomonas vaginalis to substrates

Summary Treatment ofTrichomonas vaginalis with EDTA removes their ability to adhere to glass surfaces and changes their affinity to Concanavalin A (ConA) by a different distribution of their surface structures. Filtrates of the EDTA-treatedTrichomonas passed through affinity chromatography columns (ConA bound to Sepharose 4B0 separate into 2 fractions, one fraction was bound to the ConA-Sepharose beads, the other was not. The Con A-bound fraction appears to be a glycoprotein which restores in a specific way the ability of the EDTA-treated protozoa to adhere to glass. We want to thank Dr.P. M. Comoglio for the donation of the FITC-labelled immunoglobulin fraction of anti-ConA rabbit antiserum. This work was supported by a grant from the Italian National Research Council (C.N.R.)     

The influence of perathiepine and chlorpromazine on some enzyme reactions in rat brain preparations

Zusammenfassung Die Wirkung des Thymolepticums Prothiaden [10-(4-Methylpiperazino)-10, 11-dihydrobenzo(b, f)thiepin] auf die Oxydation des Pyruvats, Oxoglutarats und Succinats sowie auf die Aktivität der Hexokinase, Glucoso-6-phosphatase und Mg⁺⁺-aktivierten, DNP-aktivierten und Mg⁺⁺Na⁺-aktivierten, K⁺-stimulierten Adenosintriphosphatase (NaKA) wurde untersucht und mit der Wirkung von Chlorpromazin verglichen. Im allgemeinen weisen beide Substanzen ähnliche Eigenschaften auf, welche in einer relativen Unwirksamkeit gegenüber glykolytischen Enzymen, Hemmung der Pyruvatoxydation und starker NaKA-Hemmung bestehen.     

Genomic revelations of a mutualism: the pea aphid and its obligate bacterial symbiont

The symbiosis of the pea aphid Acyrthosphion pisum with the bacterium Buchnera aphidicola APS represents the best-studied insect obligate symbiosis. Here we present a refined picture of this symbiosis by linking pre-genomic observations to new genomic data that includes the complete genomes of the eukaryotic and prokaryotic symbiotic partners. In doing so, we address four issues central to understanding the patterns and processes operating at the A. pisum/Buchnera APS interface. These four issues include: (1) lateral gene transfer, (2) host immunity, (3) symbiotic metabolism, and (4) regulation.     

Studies on the action of X-rays on aqueous solutions of nucleic acids and some nucleotides

Zusammenfassung Die Wirkung von Röntgenstrahlen (200 kV) auf wässerige Lösungen von Nukleinsäuren und Nukleotiden wurde unter besonderer Berücksichtigung des Einflusses von molekularem Sauerstoff und Wasserstoffsuperoxyd untersucht. Der so gefundene, nach der Bestrahlung einsetzende Abfall der Viskosität von D.N.A.-Lösungen (after-effect) kann als Hydrolyse der durch die Bestrahlung labilisierten Kohlenstoff-Phosphat-Bindungen angesehen werden. Untersuchungen über die Hydrolyse von bestrahlten Nukleotiden, -P.N.A.- und D.N.A.-Lösungen stehen in vollem Einklang mit obiger Annahme.     

Effects of chronic lithium administration on concanavalin A binding to plasma membranes from the corpus striatum of rat brain.

The effects of chronic in vivo lithium administration on mannose-containing components of plasma membranes from rat corpus striatum were examined by a 3H-concanavalin A binding displacement method. No difference on Con A binding was observed between sodium or lithium-treated rats during a 1-month period.