Enzymatic test for the detection of a riboflavin deficiency. NADPH-dependent glutathione reductase of red blood cells and its activation by FAD in vitro

Zusammenfassung Die NADPH-spezifische Glutathion-reduktaseaktivität hämolysierter Erythrozyten erscheint brauchbar als Parameter zur Erfassung von Riboflavin-mangelzuständen. Die Enzymaktivität wird in vitro durch einen Zusatz von FAD bei Riboflavinmangelratten wesentlich stärker erhöht als bei Kontrollratten. Untersuchungen mit menschlichen Erythrozyten deuten darauf hin, dass auch hier die Aktivierbarkeit des Enzyms durch FAD vom Riboflavinstatus abhängt.

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The following abbreviations are used: NADPH, reduced form of nicotinamide adenine dinucleotide phosphate (triphosphopyridine nucleotide); FAD, flavin adenine dinucleotide.     

Early brain growth in Homo erectus and implications for cognitive ability

Humans differ from other primates in their significantly lengthened growth period. The persistence of a fetal pattern of brain growth after birth is another important feature of human development. Here we present the results of an analysis of the 1.8-million-year-old Mojokerto child (Perning 1, Java), the only well preserved skull of a Homo erectus infant, by computed tomography. Comparison with a large series of extant humans and chimpanzees indicates that this individual was about 1 yr (0-1.5 yr) old at death and had an endocranial capacity at 72-84% of an average adult H. erectus. This pattern of relative brain growth resembles that of living apes, but differs from that seen in extant humans. It implies that major differences in the development of cognitive capabilities existed between H. erectus and anatomically modern humans.     

Serological properties of poly-L-tyrosine derivatives

Zusammenfassung Polytyrosin und Polytyrosylgelatine wurden mit diazotierter Arsanilsäure gekoppelt und in Lösung oder nach Fällung mit Alaun und Alkali Kaninchen injiziert. Die injizierten Substanzen wurden von keinem der Sera präzipitiert. Hingegen präzipitierte das Serum der mit gefällter Arsanilazo-polytyrosyl-gelatine injizierten Tiere Arsanilazo-Rinderserumglobulin. Wir schliessen daraus, dass Arsanilazopolytyrosin nicht als Antigen wirkt, dass es aber durch Bindung an Gelatine antigene Eigenschaften gewinnt.

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This work was supported by research grants of the National Science Foundation and the U.S. Public Health Service, and by contracts of Indiana University with the Office of Naval Research and the Atomic Energy Commission.

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On leave of absence from the Weizmann Institute of Science, Rehovoth (Israel).     

Fault lubrication during earthquakes

The determination of rock friction at seismic slip rates (about 1?m?s(-1)) is of paramount importance in earthquake mechanics, as fault friction controls the stress drop, the mechanical work and the frictional heat generated during slip. Given the difficulty in determining friction by seismological methods, elucidating constraints are derived from experimental studies. Here we review a large set of published and unpublished experiments (～300) performed in rotary shear apparatus at slip rates of 0.1-2.6?m?s(-1). The experiments indicate a significant decrease in friction (of up to one order of magnitude), which we term fault lubrication, both for cohesive (silicate-built, quartz-built and carbonate-built) rocks and non-cohesive rocks (clay-rich, anhydrite, gypsum and dolomite gouges) typical of crustal seismogenic sources. The available mechanical work and the associated temperature rise in the slipping zone trigger a number of physicochemical processes (gelification, decarbonation and dehydration reactions, melting and so on) whose products are responsible for fault lubrication. The similarity between (1) experimental and natural fault products and (2) mechanical work measures resulting from these laboratory experiments and seismological estimates suggests that it is reasonable to extrapolate experimental data to conditions typical of earthquake nucleation depths (7-15?km). It seems that faults are lubricated during earthquakes, irrespective of the fault rock composition and of the specific weakening mechanism involved.     

The structure of H5N1 avian influenza neuraminidase suggests new opportunities for drug design

The worldwide spread of H5N1 avian influenza has raised concerns that this virus might acquire the ability to pass readily among humans and cause a pandemic. Two anti-influenza drugs currently being used to treat infected patients are oseltamivir (Tamiflu) and zanamivir (Relenza), both of which target the neuraminidase enzyme of the virus. Reports of the emergence of drug resistance make the development of new anti-influenza molecules a priority. Neuraminidases from influenza type A viruses form two genetically distinct groups: group-1 contains the N1 neuraminidase of the H5N1 avian virus and group-2 contains the N2 and N9 enzymes used for the structure-based design of current drugs. Here we show by X-ray crystallography that these two groups are structurally distinct. Group-1 neuraminidases contain a cavity adjacent to their active sites that closes on ligand binding. Our analysis suggests that it may be possible to exploit the size and location of the group-1 cavity to develop new anti-influenza drugs.     

Activation with (±)N-n-propyl-nor-apomorphine (NPA) of the male rat copulatory behavior

Summary I.p. (±)N-n-propyl-nor-apomorphine HCl (NPA) influences copulatory behavior of vigorous adult male rats in the same ways as apomorphine, i.e., it reduces the latency to ejaculation as well as mount and intromission frequency. Furthermore, NPA administered to impotent male rats restores normal mating behavior in some of them.     

Sclerotization and coloration of the insect cuticle

Summary Evidence indicating linkage between the processes of cuticle hardening and coloration are reviewed. Data and observations for the mutants black and ebony inDrosophila melanogaster are used to construct a possible model for the relationship between these developmental events.     

The massive binary companion star to the progenitor of supernova 1993J

The massive star that underwent a collapse of its core to produce supernova (SN)1993J was subsequently identified as a non-variable red supergiant star in images of the galaxy M81 taken before explosion. It showed an excess in ultraviolet and B-band colours, suggesting either the presence of a hot, massive companion star or that it was embedded in an unresolved young stellar association. The spectra of SN1993J underwent a remarkable transformation from the signature of a hydrogen-rich type II supernova to one of a helium-rich (hydrogen-deficient) type Ib. The spectral and photometric peculiarities were best explained by models in which the 13-20 solar mass supergiant had lost almost its entire hydrogen envelope to a close binary companion, producing a 'type IIb' supernova, but the hypothetical massive companion stars for this class of supernovae have so far eluded discovery. Here we report photometric and spectroscopic observations of SN1993J ten years after the explosion. At the position of the fading supernova we detect the unambiguous signature of a massive star: the binary companion to the progenitor.