Kinins in cerebrospinal fluid: reduced concentration in spontaneously hypertensive rats

Rat cerebrospinal fluid contains peptides which displace radiolabeled bradykinin from its specific antibodies. Two peptides which showed the same retention time as kallidin and bradykinin in a reverse phase high pressure liquid chromatography system were detected in cerebrospinal fluid of rats. The concentration of radioimmunologically detected kinins in the cerebrospinal fluid of spontaneously hypertensive rats of the Okamoto strain was lower than that of the Wistar Kyoto control rats.     

A low level of extragalactic background light as revealed by gamma-rays from blazars

The diffuse extragalactic background light consists of the sum of the starlight emitted by galaxies through the history of the Universe, and it could also have an important contribution from the 'first stars', which may have formed before galaxy formation began. Direct measurements are difficult and not yet conclusive, owing to the large uncertainties caused by the bright foreground emission associated with zodiacal light. An alternative approach is to study the absorption features imprinted on the gamma-ray spectra of distant extragalactic objects by interactions of those photons with the background light photons. Here we report the discovery of gamma-ray emission from the blazars H 2356 - 309 and 1ES 1101 - 232, at redshifts z = 0.165 and z = 0.186, respectively. Their unexpectedly hard spectra provide an upper limit on the background light at optical/near-infrared wavelengths that appears to be very close to the lower limit given by the integrated light of resolved galaxies. The background flux at these wavelengths accordingly seems to be strongly dominated by the direct starlight from galaxies, thus excluding a large contribution from other sources-in particular from the first stars formed. This result also indicates that intergalactic space is more transparent to gamma-rays than previously thought.     

Expression analysis ofgdcsP promoter from C3-C4 intermediate plantFlaveria anomala in transgenic rice

ThegdcsP promoter isolated from C₃-C₄ intermediate plantFlaveria anomala was fused to the β-glucuronidase (GUS) gene. The chimeric gene was inserted into the binary vector pBin19 and introduced into the rice (Oryza sativa L.) cv. 8706 byAgrobacteriummediated gene transfer. GUS activity can be detected in leaf, leaf sheath, stem and root tissues via fluorometric GUS assay. However, no GUS activity was found in mature endosperm. Histochemical localization revealed that GUS expression was exclusively restricted to vascular tissues in transgenic plants. This promoter also showed spatial-temporal expression patterns that GUS expression declined significantly with the maturity of plants. These expression patterns make thegdcsP promoter extremely valuable in the applied biotechnology that needs target gene expression restricted to vascular tissues.     

Field-aligned current distribution and response to interplanetary conditions during a superstorm―CHAMP observation

With geomagnetic measurements on board of CHAMP satellite, the characteristics of global large-scale field-aligned currents （FACs） in the topside ionosphere are investigated along with their responses to interplanetary conditions for the superstorm of November, 2003. It is found that （1） The storm-time FAC densities enhanced greatly in comparison with quiet period and the enhancements show hemispheric asymmetry of both summer-winter and sunlit-dark. （2） For the first time, it is revealed that the lati- tude-integrated FAC density is controlled mainly by solar wind dynamic pressure rather than iMF. （3） FACs expanded equatorward dramatically, with the lowest latitude being 45° MLat or more; on the dayside this expansion was controlled directly by IMF Bz, showing an interaction time scale of about 25 min in the solar wind-magnetosphere-ionosphere coupling system, and a nonlinear saturation of the equatorward expansion when IMF Bz 〈 -30 nT; while on the nightside, the expansion and recovery lagged about 3 h behind the IMF changes but nearly in phase with changes of SYM-H index. （4） During the storm main phase, the nightside FAC latitude coverage extended to 25° or wider, appearing multi-sheet current structure with more than 10 sheets.     

HIV-1 evades antibody-mediated neutralization through conformational masking of receptor-binding sites

The ability of human immunodeficiency virus (HIV-1) to persist and cause AIDS is dependent on its avoidance of antibody-mediated neutralization. The virus elicits abundant, envelope-directed antibodies that have little neutralization capacity. This lack of neutralization is paradoxical, given the functional conservation and exposure of receptor-binding sites on the gp120 envelope glycoprotein, which are larger than the typical antibody footprint and should therefore be accessible for antibody binding. Because gp120-receptor interactions involve conformational reorganization, we measured the entropies of binding for 20 gp120-reactive antibodies. Here we show that recognition by receptor-binding-site antibodies induces conformational change. Correlation with neutralization potency and analysis of receptor-antibody thermodynamic cycles suggested a receptor-binding-site 'conformational masking' mechanism of neutralization escape. To understand how such an escape mechanism would be compatible with virus-receptor interactions, we tested a soluble dodecameric receptor molecule and found that it neutralized primary HIV-1 isolates with great potency, showing that simultaneous binding of viral envelope glycoproteins by multiple receptors creates sufficient avidity to compensate for such masking. Because this solution is available for cell-surface receptors but not for most antibodies, conformational masking enables HIV-1 to maintain receptor binding and simultaneously to resist neutralization.     

Intron creation and DNA repair

The genesis of the exon–intron patterns of eukaryotic genes persists as one of the most enigmatic questions in molecular genetics. In particular, the origin and mechanisms responsible for creation of spliceosomal introns have remained controversial. Now the issue appears to have taken a turn. The formation of novel introns in eukaryotes, including some vertebrate lineages, is not as rare as commonly assumed. Moreover, introns appear to have been gained in parallel at closely spaced sites and even repeatedly at the same position. Based on these discoveries, novel hypotheses of intron creation have been developed. The new concepts posit that DNA repair processes are a major source of intron formation. Here, after summarizing the current views of intron gain mechanisms, I review findings in support of the DNA repair hypothesis that provides a global mechanistic scenario for intron creation. Some implications on our perception of the mosaic structure of eukaryotic genes are also discussed.     

Distinct functions of Crumbs regulating slit diaphragms and endocytosis in <Emphasis Type="Italic">Drosophila</Emphasis> nephrocytes

Mammalian podocytes, the key determinants of the kidney’s filtration barrier, differentiate from columnar epithelial cells and several key determinants of apical–basal polarity in the conventional epithelia have been shown to regulate podocyte morphogenesis and function. However, little is known about the role of Crumbs, a conserved polarity regulator in many epithelia, for slit-diaphragm formation and podocyte function. In this study, we used Drosophila nephrocytes as model system for mammalian podocytes and identified a conserved function of Crumbs proteins for cellular morphogenesis, nephrocyte diaphragm assembly/maintenance, and endocytosis. Nephrocyte-specific knock-down of Crumbs results in disturbed nephrocyte diaphragm assembly/maintenance and decreased endocytosis, which can be rescued by Drosophila Crumbs as well as human Crumbs2 and Crumbs3, which were both expressed in human podocytes. In contrast to the extracellular domain, which facilitates nephrocyte diaphragm assembly/maintenance, the intracellular FERM-interaction motif of Crumbs is essential for regulating endocytosis. Moreover, Moesin, which binds to the FERM-binding domain of Crumbs, is essential for efficient endocytosis. Thus, we describe here a new mechanism of nephrocyte development and function, which is likely to be conserved in mammalian podocytes.     

Cationic and secretory effects of BPDZ 44 and diazoxide in rat pancreatic islets

The present study aimed at comparing the effects of low concentrations of BPDZ 44, a new pyridothiadiazine derivative, and diazoxide on⁸⁶Rb outflow,⁴⁵Ca outflow,⁴⁵Ca uptake and insulin release from rat pancreatic islets. Both drugs caused similar modifications, but the effects of BPDZ 44 on the cationic and secretory events were much more marked than those of diazoxide. It is suggested that BPDZ 44 could be valuable tool for further studies of the K_ATP channels.     

Ein Verfahren zur kolorimetrischen Bestimmung des Thyroxins

Summary A colorimetric method for the determination of thyroxin has been worked out. Directions for practical use are given.