Inelastic neutron-scattering study of the proton transfer dynamics in polyglycine I at 20 K

Inelastic neutron-scattering (INS) spectra of three isotopic derivatives of polyglycine I (-COCH2NH-)n, (-COCD2NH-)n, and (-COCH2ND-)n at 20 K are presented from 30 to 4000 cm(-1). The band frequencies are compared to those observed in the infrared and Raman. Assignments in terms of group vibrations are proposed. These mostly resemble previous assignment schemes, except for the amide bands. The INS intensities reveal that the proton dynamics for the (N)H proton are totally different from those proposed previously. They are independent of the molecular frame and the valence bond approach is not consistent with observation. A phenomenological approach is proposed in terms of localized modes. The calculated intensities reveal that the (N)H stretching mode has two components at approximately 1377 and 1553 cm(-1). This is a dramatic change compared to all former assignments at approximately 3280 cm(-1) based on infrared and Raman data. These proton-dynamics are associated with a weakening of the NH bond due to the ionic character of the hydrogen bond (N(delta-)...H+...O(delta'-)) and proton transfer. The infrared and Raman spectra are re-examined and a new assignment scheme is proposed for the amide bands; the amide A and B bands are re-assigned to the overtones of the stretching modes. A symmetric double-minimum potential for the proton is consistent with all the observations.     

Insertional mutagenesis to isolate acetate-requiring mutants in Chlamydomonas reinhardtii

Abstract An arg 7 mutant of the green alga Chlamydomonas reinhardtii was transformed with pARG7.8, a plasmid bearing the wild-type ARG 7 gene. Out of 4100 arg⁺ transformants selected on an arginine-free medium supplemented with acetate, nine failed to grow on acetate-free medium (ac⁻ mutants). The results of the genetic and molecular analysis of several ac⁻ mutants are in agreement with the hypothesis that they originated from insertion of the incoming plasmid into the nuclear genome. These mutants should constitute valuable tools for isolating the corresponding wild-type genes after plasmid rescue into Escherichia coli .     

Detection of renal cell carcinoma-associated markers via proteome- and other 'ome'-based analyses.

Proteome analysis has rapidly developed in the post-genome era and is now widely accepted as the complementary technology for genetic profiling. It has been shown to be a powerful tool for studying human diseases and for identifying novel prognostic, diagnostic and therapeutic markers. This review focuses on the identification of new biomarkers and therapeutic targets for renal cell carcinoma using different 'ome'-based technologies.     

Auswirkungen von Hochspannungstrassen auf die Fl?chennutzung überwinternder Bl??- und Saatg?nseAnser albifrons, A. fabalis

Zusammenfassung  Während das Mortalitätsrisiko für Vögel durch Drahtanflug und Stromschlag an Hochspannungsleitungen vielfach untersucht wurde, könnte auch ein Einfluß von Hochspannungstrassen (110 kV) auf Vögel bestehen, die sich am Boden aufhalten. Dieser wurde 1994/95 am Beispiel der Flächennutzung überwinternder Bläß- und Saatgänse (Anser albifrons, A. fabalis) am Unteren Niederrhein untersucht. Da Gänse offene ungestörte Äsungsflächen beanspruchen, wurde der Arbeitshypothese nachgegangen, daß trassennahe Bereiche von Gänsen gemieden bzw. vermindert genutzt werden. Die Besuchsfrequenz von vier häufig genutzten trassenüberspannten Äsungsflächen wurde ermittelt. Im Anschluß an die einzelnen mehrtägigen Beäsungsphasen wurde die Losungsdichte (LD) als Maß der Flächennutzung senkrecht zum Trassenverlauf bestimmt. An 16–20 m hohen Trassen stieg die LD mit zunehmender Entfernung zur Trasse. Eine signifikante Abnahme der LD trat unterhalb von 40–80 m Abstand zur Trasse ein. Kleine Teilflächen, die durch die Trassen von größeren Bereichen abgetrennt sind, wurden weniger genutzt. An einer 60 m hohen, den Rhein Überquerenden Trasse, konnte kein trassenbedingter Unterschied der LD festgestellt werden. Mögliche Ursachen für die beschriebenen Effekte werden diskutiert.

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The impact of power lines on field selection and grazing intensity of wintering White-fronted- and Bean GeeseAnser albifrons, A. fabalis

In addition to studies about the mortality risk by collision and electrocution power lines may have an impact on birds during foraging behaviour on the ground. We examined this question in geese (Anser albfrons, A. fabalis) wintering in the lower Rhine area of North Rhine Westfalia (FRG) 1994/95. Because geese prefer large areas with low levels of disturbance by human activities or urbanic structures like buildings or roads, we hypothesized that they might be disturbed by the presence of power lines in their foraging sites and thus avoid areas next to the lines. To quantify the grazing intensity in relation to the distance from the power lines (110 kV), dropping densities have been repeatedly counted after independant grazing intervals in four different feeding sites. Our data show that: 1. Grazing intensity increases with the distance to power lines of low height. Significantly reduced grazing levels have been found in distances less than 80 to 40 m to the power lines. 2. No effects have been observed for a power line in an area next to the river rhine where the wires crossed the ground in a height of about 60 metres. 3. In small pasture or field areas, cut off by power lines from large ones, a generally reduced grazing amount is evident. Several conceivable reasons for the described effects are discussed.

     

A broadly active viral inhibitor in human and animal organ extracts and body fluids

To help assess the possibility that a newly described viral inhibitor from cell cultures might play a natural defensive role in vivo, its distribution and concentration in human and animal organ extracts and body fluids were investigated. The concentration of the inhibitor was high in human liver, heart muscle, splenic extracts, and human serum and milk. The inhibitor in the body was indistinguishable from a previously described inhibitor produced in cell cultures that was characterized by broad antiviral activity, lack of target cell species specificity, lack of induction of stable antiviral activity in cells, rapid reversibility of antiviral action, prevention of virus attachment, and stability at 100 degrees C. Sixteen virus plaque reduction units of the inhibitor diminished the yield of poliovirus in vitro by more than 1000-fold. Additional evidence that contact-blocking viral inhibitor (CVI) inhibits vaccinia virus attachment to cells is presented. A role for the inhibitor in natural defense against viral infections is possible.     

Protein modules

As the database of protein sequences grows it is becoming apparent that many proteins are constructed from relatively few modular units that appear many times. Determination of the three-dimensional structure of such modules by NMR has been possible due to their production in relatively large quantities by recombinant DNA techniques. The knowledge gained about the structure of individual modules can then be used to predict their properties in a variety of intact proteins.