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Antal Festetics 《Ethology : formerly Zeitschrift fur Tierpsychologie》1968,25(6):659-665
Für die Schleiereule (Tyto alba) wird während der Fütterungszeit eine nächtliche Zweiphasenaktivität beschrieben. An zwei verschiedenen Brüten wurde in der Nacht eine vormitternächtliche Aktivitätsphase von etwa 2 Std. Länge und eine etwas kürzere Morgenaktivitätsphase beobachtet. Ein solcher Bigeminus war von vielen Säugetierarten, nicht aber von nachtaktiven Vögeln bekannt. Bei drei etwa 1 Monat alten Jungen muß jeder Altvogel, binnen 3 bis 3,5 Stunden, also während der Hälfte der Dunkelperiode, mindestens 5 Stück mäuse- bzw. sperlingsgroße Beutetiere erspähen und erbeuten. Die Analyse von Schädelresten aus dem Gewöllmaterial der Jungeulen ergibt kein reales Bild des Speisezettels, da die Altvögel den Kopf der Beute nicht selten abreißen, wodurch diese in den Speiballen nicht aufscheinen. 相似文献
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Argyrophilic nuclear proteins, known to be functionally associated with ribosomal genes, were localized, in four-, eight-, and 16-cell bovine embryo blastomere nuclei using two different silver-staining procedures. Within the eight-cell cleavage stage by the process of embryonal nucleologenesis in the cow embryo the full-capacity ribosome-producing machinery is established. In the four-cell embryo, many patches and islands of argyrophilic (Ag+) material were detected in the nucleoplasm. The nucleolus-precursor bodies (NPBs), composed uniformly of a homogeneous compact mass, were completely devoid of any silver staining. On the other hand, clear-cut localization of argyrophilic proteins was detected during the eight-cell stage either inside the transforming NPBs or in the close vicinity, or in the already differentiated nucleolus. In compact, nonvacuolated NPB, an intensive Ag+ area was detected, in the form of a lenticle, at the periphery of the NPB. During and following vacuolation of the NPB, no Ag+ was detected inside these vacuoles. It was seen, however, in the dense fibrillar nucleolar component surrounding the smaller vacuoles formed at the time of the establishment of nucleolar structure. Ag+ areas were seen repeatedly in the vicinity of NPBs, probably a part of the nucleolus-associated chromatin or, alternatively, representing the extranucleolar bodies. In blastomere nuclei of 16-cell embryos, already possessing reticulated nucleoli known from intensively synthesizing somatic cells, the silver-staining pattern corresponded to the usual situation in differentiated cells: slight staining of fibrillar centers, heavy labelling in the dense fibrillar component, and absence of silver deposits in the granular component.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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The phylogeny of Greya Busck (Lepidoptera: Prodoxidae) was inferred from
nucleotide sequence variation across a 765-bp region in the cytochrome
oxidase I and II genes of the mitochondrial genome. Most parsimonious
relationships of 25 haplotypes from 16 Greya species and two outgroup
genera (Tetragma and Prodoxus) showed substantial congruence with the
species relationships indicated by morphological variation. Differences
between mitochondrial and morphological trees were found primarily in the
positions of two species, G. variabilis and G. pectinifera, and in the
branching order of the three major species groups in the genus. Conflicts
between the data sets were examined by comparing levels of homoplasy in
characters supporting alternative hypotheses. The phylogeny of Greya
species suggests that host-plant association at the family level and larval
feeding mode are conservative characters. Transition/transversion ratios
estimated by reconstruction of nucleotide substitutions on the phylogeny
had a range of 2.0-9.3, when different subsets of the phylogeny were used.
The decline of this ratio with the increase in maximum sequence divergence
among taxa indicates that transitions are masked by transversions along
deeper internodes or long branches of the phylogeny. Among transitions,
substitutions of A-->G and T-->C outnumbered their reciprocal
substitutions by 2-6 times, presumably because of the approximately 4:1
(77%) A+T-bias in nucleotide base composition. Of all transversions,
73%-80% were A<-->T substitutions, 85% of which occurred at third
positions of codons; these estimates did not decrease with an increase in
maximum sequence divergence of taxa included in the analysis. The high
frequency of A<-->T substitutions is either a reflection or an
explanation of the 92% A+T bias at third codon positions.
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Tamara Kubasova Sára Antal Z. Somosy G. J. Köteles 《Radiation and environmental biophysics》1984,23(4):269-277
Summary For studies on cell membranes, mice were exposed to mixed neutron + gamma reactor-radiation in the range of total doses from 0.5 to 4.5 Gy. Changes in functional activity of plasma membranes of erythrocytes, platelets, and lymphocytes were followed by a lectin-binding technique at various intervals afterwards. The amount of3H-concanavalin A bound to cells altered considerably during the 1st h after irradiation in all cell types. Lymphocytes and platelets, however, were more sensitive than erythrocytes as increased lectin-binding could already be observed after 0.5 Gy. The binding ability of these cells performed oscillatory behaviour. In addition, alterations in shapes and ultrastructure of cell surfaces and intracellular membranes were observed. 相似文献
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Antal Németh Birgitta Strandvik Hans Glaumann 《Virchows Archiv. B, Cell pathology including molecular pathology》1983,44(1):15-33
Sixteen children (aged between 1 month and 20 years) with alpha-1-antitrypsin deficiency (PiZ) were investigated by liver biopsy on one or more occasions. Eight patients had suffered from neonatal cholestasis, and two of them were investigated during the cholestatic period as well. The clinical status and liver function tests were compared with the light and electron microscopical findings. According to the light microscopical analyses at the latest investigation, the cholestatic and noncholestatic patients were classified as healthy, fibrotic or cirrhotic cases. All livers displayed periodic acid-Schiff positive, diastase-resistant globules in some but not all periportally located hepatocytes. By electron microscopy accumulation of retained secretory material was found in all PiZ patients. This accumulation was most conspicuous in the smooth endoplasmic reticulum of hepatocytes. alpha-1-antitrypsin deficiency seems to affect some, but not all hepatocytes. In the affected cells disappearance or hypotrophy of the Golgi complex could be observed. The intracellular transport of very low density lipoproteins (VLDL) was apparently not affected. The migration block in alpha-1-antitrypsin deficiency seems to occur before transportation to the Golgi complex. The extent of the involvement was not strictly age-dependent. There was no ultrastructural evidence of subclinical cholestasis as a possible triggering factor in the development of cirrhosis. 相似文献