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321.
322.
ULRIK KVIST BJ
RN A. AFZELIUS LENNART NILSSON 《Development, growth & differentiation》1980,22(3):543-554
In vitro decondensation of human sperm chromatin induced by the activation of an intrinsic mechanism was studied by light microscopy, scanning and transmission electron microscopy. Morphological evidence was provided to support the concept that this mechanism is essential for the chromatin decondensation occurring in vivo. Prostatic zinc is hypothesized to preserve this potential decondensation ability from oxidative destruction, by reversibly binding to free thiol-groups. The unique occurrence of disulphide-stabilized structures in eutherian spermatozoa may serve to protect the spermatozoon from structural degradation by its own proteolytic activity during the relatively slow passage through the eutherian egg investments. 相似文献
323.
Hellekant G.; Hladik C.M.; Dennys V.; Simmen B.; Roberts T.W.; Glaser D.; DuBois G.; Walters D.E. 《Chemical senses》1993,18(3):307-320
The relationship between phylogeny and taste is of growing interest.In this study we present recordings from the chorda tympaniproper (CT) nerve of two lemuriforme primates, the lesser mouselemur (Microcebus murinus) and the mongoose lemur (Eulemur mongoz),to an array of taste stimuli which included the sweeteners acesulfame-K,alitame, aspartame, D-glucose, dulcin, monellin, neohesperidindihydrochalcone (NHDHC), saccharin, sodium superaspartame, stevioside,sucralose (TGS), sucrose, suosan, thaumatin and xylitol, aswell as the nonsweet stimuli NaC1, citric acid, tanninand quinine hydrochloride. In M.murinus the effects of the tastemodifiers gymnemic acid and miraculin on the CT response wererecorded. Conditioned taste aversion (CTA) experiments in M.murinusand two-bottle preference (TBP) tests in E.mongoz were alsoconducted. We found that all of the above tastants except thaumatinelicited a CT response in both species. The CTA technique showedthat M.murinus generalized from sucrose to monellin but notto thaumatin. The intake of aspartame, ranging in concentrationfrom 0.1 to 30 mM was measured in E.mongoz with TBP tests. Atno concentration did we see a preference, but there was a significantrejection of 10 and 30 mM aspartame (P 相似文献
324.
GUNNAR LARSEN JÖRN THIEDE 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1971,4(1):63-69
The paper deals with radiographic studies of Middle Cambrian 'fragment limestone', and Upper Cambrian anthraconite concretions from Bornholm (Denmark). A very simple method provides good insight into the sedimentary structures of the rocks and hence a good foundation for interpretation of the lithogenesis. 相似文献
325.
Brit Mollenhauer Frederick DuBois Bowman Daniel Drake Jimmy Duong Kaj Blennow Omar El‐Agnaf Leslie M. Shaw Jennifer Masucci Peggy Taylor Robert M. Umek Jill M. Dunty Chris L. Smith Erik Stoops Hugo Vanderstichele Adrian W. Schmid Marc Moniatte Jing Zhang Niels Kruse Hilal A. Lashuel Charlotte Teunissen Tanja Schubert Kuldip D. Dave Samantha J. Hutten Henrik Zetterberg 《Journal of neurochemistry》2019,149(1):126-138
326.
Various organs of Leucaena leucocephala (Lam.) de Wit were analyzed for their levels of total nitrogen and free amino acids as well as for changes in free amino acid pools from the time of germination through nodulation. Also an assessment was made of the sink of fixed N2 (transport product) in the nodules using 15N methodology. L. leucocephala organs showed total nitrogen levels similar to those of other legumes. Asparagine was the most prevalent amino acid in the nodules and roots followed by glutamate and mimosine. Asparagine was the second most common amino acid in the leaves and stems, with mimosine being the most abundant. Strong correlations were found between the total plant levels of aspartate and glutamate, asparagine and NH4+, acetylene reduction and glutamate, and asparagine and plant age. Asparagine amino- and amide-N accounted for over 75% of the fixed 15N2 in nodules. It was concluded that L. leucocephala is an asparagine transporter of fixed N2 in the nodule. 相似文献
327.