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41.
Zusammenfassung Es wird mittels synthetischer Peptide (Ib, II) bewiesen, dass eine Disulphidgruppe für die « insulinähnliche » Wirkung von mit dem Oxytocin verwandten Peptiden am Fettgewebe der Rattenepididymis nicht notwendig ist. Somit wird ein von Disulphidaustausch abhängiger Wirkungsmechanismus ausgeschlossen. 相似文献
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The following species of the fly genus Lispe are redescribed: L. albitarsis (Stein, 1898), L. latana Snyder, 1949, L. levis (Stein, 1911), L. lisarba Snyder, 1949, L. nasoni (Stein, 1898), L. serotina Wulp, 1896, L. setuligera (Stein, 1911) and L. vilis (Stein, 1911). Additionally, a new diagnosis is proposed for L. rufitibialis Macquart, 1843, and in order to fix the identity of the name the lectotype is designated. To facilitate species identification, a pictorial key for the species of Lispe in the Neotropical region and distribution maps are presented, together with the first published illustrations of the male terminalia of L. latana, L. levis and L. lisarba, and the female of L. lisarba. 相似文献
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Saraux C Le Bohec C Durant JM Viblanc VA Gauthier-Clerc M Beaune D Park YH Yoccoz NG Stenseth NC Le Maho Y 《Nature》2011,469(7329):203-206
In 2007, the Intergovernmental Panel on Climate Change highlighted an urgent need to assess the responses of marine ecosystems to climate change. Because they lie in a high-latitude region, the Southern Ocean ecosystems are expected to be strongly affected by global warming. Using top predators of this highly productive ocean (such as penguins) as integrative indicators may help us assess the impacts of climate change on marine ecosystems. Yet most available information on penguin population dynamics is based on the controversial use of flipper banding. Although some reports have found the effects of flipper bands to be deleterious, some short-term (one-year) studies have concluded otherwise, resulting in the continuation of extensive banding schemes and the use of data sets thus collected to predict climate impact on natural populations. Here we show that banding of free-ranging king penguins (Aptenodytes patagonicus) impairs both survival and reproduction, ultimately affecting population growth rate. Over the course of a 10-year longitudinal study, banded birds produced 41% [corrected] fewer chicks and had a survival rate 16 percentage points [corrected] lower than non-banded birds, demonstrating a massive long-term impact of banding and thus refuting the assumption that birds will ultimately adapt to being banded. Indeed, banded birds still arrived later for breeding at the study site and had longer foraging trips even after 10?years. One of our major findings is that responses of flipper-banded penguins to climate variability (that is, changes in sea surface temperature and in the Southern Oscillation index) differ from those of non-banded birds. We show that only long-term investigations may allow an evaluation of the impact of flipper bands and that every major life-history trait can be affected, calling into question the banding schemes still going on. In addition, our understanding of the effects of climate change on marine ecosystems based on flipper-band data should be reconsidered. 相似文献
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Evidence for the presence of viable endothelial cells in cultures derived from dissociated rat brain 总被引:6,自引:0,他引:6
Summary The morphology and histochemistry of dissociated newborn rat brain was studied in tissue culture. Direct microscopy of developing cells, electron microscopy and the alkaline phosphatase activity were used to identify the capillary endothelial cells.Acknowledgments. We thank Dr J. Gripenberg for technical assistance. This research was supported by Finnish Cultural Foundation and carried out during the tenure of a fellowship provided for F. J. from the Finnish-Hungarian Cultural Exchange Program. 相似文献
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M. Lebl V. Bojanovska T. Barth K. Jošt 《Cellular and molecular life sciences : CMLS》1978,34(12):1543-1545
Summary Deamino-1-carba-oxytocin analogs with a chemically reactive group in position 4 were demonstrated to act as noncompetitive oxytocin inhibitors in the assay on isolated rat uterus. 相似文献
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Anske Van den Abbeele Sarah De Clercq Ariane De Ganck Veerle De Corte Berlinda Van Loo Sameh Hamdy Soror Vasundara Srinivasan Jan Steyaert Joël Vandekerckhove Jan Gettemans 《Cellular and molecular life sciences : CMLS》2010,67(9):1519-1535
RNA interference has tremendously advanced our understanding of gene function but recent reports have exposed undesirable
side-effects. Recombinant Camelid single-domain antibodies (VHHs) provide an attractive means for studying protein function without affecting gene expression.
We raised VHHs against gelsolin (GsnVHHs), a multifunctional actin-binding protein that controls cellular actin organization
and migration. GsnVHH-induced delocalization of gelsolin to mitochondria or the nucleus in mammalian cells reveals distinct
subpopulations including free gelsolin and actin-bound gelsolin complexes. GsnVHH 13 specifically recognizes Ca2+-activated gelsolin (K
d ~10 nM) while GsnVHH 11 binds gelsolin irrespective of Ca2+ (K
d ~5 nM) but completely blocks its interaction with G-actin. Both GsnVHHs trace gelsolin in membrane ruffles of EGF-stimulated
MCF-7 cells and delay cell migration without affecting F-actin severing/capping or actin nucleation activities by gelsolin.
We conclude that VHHs represent a potent way of blocking structural proteins and that actin nucleation by gelsolin is more
complex than previously anticipated. 相似文献