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301.
Ohne Zusammenfassung 相似文献
302.
C. A. Grob T. Reichstein H. Rosenthal 《Cellular and molecular life sciences : CMLS》1945,1(8):275-276
Summary As previously reported the larvae ofTribolium confusum require two unknown factors obtainable from yeast apart from various vitamines of the B-group for normal growth. One of these possesses acidic properties. This factor could be fully replaced by a folic acid preparation of potency 4000 kindly placed at our disposal by Prof.R. J. Williams. This may be regarded as a possibility but not as a proof that folic acid is the reported factor.
C. A. Grob dankt der Haco-Gesellschaft AG., Gümligen, für die Unterstützung dieser Arbeit. 相似文献
C. A. Grob dankt der Haco-Gesellschaft AG., Gümligen, für die Unterstützung dieser Arbeit. 相似文献
303.
304.
Luiz A. Rocha Joseph D. DiBattista Tane H. Sinclair-Taylor Michael L. Berumen 《Journal of Natural History》2020,54(15-16):1019-1023
ABSTRACT Here we document three cases of mimicry in coral reef fishes not previously reported in the literature involving two groupers (Epinephelus leucogrammicus and Plectropomus marisrubri) and a soapfish (Diploprion drachi) as mimics, and two wrasses (Larabicus quadrilineatus and Cheilinus quinquecinctus) and a blenny (Meiacanthus nigrolineatus) as models. All three cases are of aggressive mimicry, with a predatory species mimicking a harmless one, and in one of the cases, the mimicry is also Müllerian, where both the predator and harmless species are unpalatable. 相似文献
305.
正Published online:14 March 2014óScience China Press and Springer-Verlag Berlin Heidelberg 2014Erratum to:Chin.Sci.Bull.(2014)59(5–6):528–532DOI 10.1007/s11434-013-0060-1In the original publication of this paper,the first name and the last name of the first author has been documented 相似文献
306.
We have taken a new approach to test the commonly accepted, but recently questioned, principle of clonal inheritance of vertebrate mitochondrial DNA (mtDNA) by relating its inheritance to a female-specific marker of nuclear DNA. Whereas this is impossible in organisms with male heterogamy (such as mammals), we show here that genealogies of mtDNA and the female-specific W chromosome of a bird species are completely concordant. Our results indicate that inheritance of mtDNA is free of detectable recombination effects over an evolutionary timescale. 相似文献
307.
Superconductivity in CaCuO2 as a result of field-effect doping. 总被引:2,自引:0,他引:2
J H Sch?n M Dorget F C Beuran X Z Zu E Arushanov C Deville Cavellin M Lagu?s 《Nature》2001,414(6862):434-436
Understanding the doping mechanisms in the simplest superconducting copper oxide-the infinite-layer compound ACuO2 (where A is an alkaline earth metal)-is an excellent way of investigating the pairing mechanism in high-transition-temperature (high-Tc) superconductors more generally. Gate-induced modulation of the carrier concentration to obtain superconductivity is a powerful means of achieving such understanding: it minimizes the effects of potential scattering by impurities, and of structural modifications arising from chemical dopants. Here we report the transport properties of thin films of the infinite-layer compound CaCuO2 using field-effect doping. At high hole- and electron-doping levels, superconductivity is induced in the nominally insulating material. Maximum values of Tc of 89 K and 34 K are observed respectively for hole- and electron-type doping of around 0.15 charge carriers per CuO2. We can explore the whole doping diagram of the CuO2 plane while changing only a single electric parameter, the gate voltage. 相似文献
308.
Novel neurotrophic factor CDNF protects and rescues midbrain dopamine neurons in vivo 总被引:1,自引:0,他引:1
Lindholm P Voutilainen MH Laurén J Peränen J Leppänen VM Andressoo JO Lindahl M Janhunen S Kalkkinen N Timmusk T Tuominen RK Saarma M 《Nature》2007,448(7149):73-77
In Parkinson's disease, brain dopamine neurons degenerate most prominently in the substantia nigra. Neurotrophic factors promote survival, differentiation and maintenance of neurons in developing and adult vertebrate nervous system. The most potent neurotrophic factor for dopamine neurons described so far is the glial-cell-line-derived neurotrophic factor (GDNF). Here we have identified a conserved dopamine neurotrophic factor (CDNF) as a trophic factor for dopamine neurons. CDNF, together with its previously described vertebrate and invertebrate homologue the mesencephalic-astrocyte-derived neurotrophic factor, is a secreted protein with eight conserved cysteine residues, predicting a unique protein fold and defining a new, evolutionarily conserved protein family. CDNF (Armetl1) is expressed in several tissues of mouse and human, including the mouse embryonic and postnatal brain. In vivo, CDNF prevented the 6-hydroxydopamine (6-OHDA)-induced degeneration of dopaminergic neurons in a rat experimental model of Parkinson's disease. A single injection of CDNF before 6-OHDA delivery into the striatum significantly reduced amphetamine-induced ipsilateral turning behaviour and almost completely rescued dopaminergic tyrosine-hydroxylase-positive cells in the substantia nigra. When administered four weeks after 6-OHDA, intrastriatal injection of CDNF was able to restore the dopaminergic function and prevent the degeneration of dopaminergic neurons in substantia nigra. Thus, CDNF was at least as efficient as GDNF in both experimental settings. Our results suggest that CDNF might be beneficial for the treatment of Parkinson's disease. 相似文献
309.
van Kasteren SI Kramer HB Jensen HH Campbell SJ Kirkpatrick J Oldham NJ Anthony DC Davis BG 《Nature》2007,446(7139):1105-1109
One of the most important current scientific paradoxes is the economy with which nature uses genes. In all higher animals studied, we have found many fewer genes than we would have previously expected. The functional outputs of the eventual products of genes seem to be far more complex than the more restricted blueprint. In higher organisms, the functions of many proteins are modulated by post-translational modifications (PTMs). These alterations of amino-acid side chains lead to higher structural and functional protein diversity and are, therefore, a leading contender for an explanation for this seeming incongruity. Natural protein production methods typically produce PTM mixtures within which function is difficult to dissect or control. Until now it has not been possible to access pure mimics of complex PTMs. Here we report a chemical tagging approach that enables the attachment of multiple modifications to bacterially expressed (bare) protein scaffolds: this approach allows reconstitution of functionally effective mimics of higher organism PTMs. By attaching appropriate modifications at suitable distances in the widely-used LacZ reporter enzyme scaffold, we created protein probes that included sensitive systems for detection of mammalian brain inflammation and disease. Through target synthesis of the desired modification, chemistry provides a structural precision and an ability to retool with a chosen PTM in a manner not available to other approaches. In this way, combining chemical control of PTM with readily available protein scaffolds provides a systematic platform for creating probes of protein-PTM interactions. We therefore anticipate that this ability to build model systems will allow some of this gene product complexity to be dissected, with the aim of eventually being able to completely duplicate the patterns of a particular protein's PTMs from an in vivo assay into an in vitro system. 相似文献
310.
Hessa T Meindl-Beinker NM Bernsel A Kim H Sato Y Lerch-Bader M Nilsson I White SH von Heijne G 《Nature》2007,450(7172):1026-1030