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91.
Hamplova B Novakova O Tvrzicka E Kolar F Novak F 《Cell biochemistry and biophysics》2005,43(1):105-117
Total protein kinase C (PKC) activity, its isoform expression, and concentration and fatty acid (FA) composition of diacylglycerol
(DAG) were determined in the left ventricular myocardium of the rat during early postnatal development (d 2, 3, 5, 7, and
10). PKC activity measured by the incorporation of 32P into histone IIIS decreased between d 2 and 10 in the homogenate as well as in cytosolic, membrane (100,000g), and nuclear-cytoskeletal-myofilament
fractions (1000g). Likewise, the expression of PKC isoforms (α, δ, and ε) determined by immunoblotting generally declined
during the period analyzed, although with a variable pattern. In the membrane and nuclear cytoskeletal myofilament fractions,
PKCδ and PKCε expression decreased markedly by d 3, returning to or close to the d 2 level immediately on d 5. PKCα expression
in the membrane fraction remained almost unchanged by d 7, declining thereafter. PKCδ and PKCε were associated predominantly
with particulate fractions, whereas PKCα was more abundant in the cytosolic fraction. DAG concentration exhibited a significant
decline by d 5, consistent with the decrease in maximal PKC activity. The unsaturation index of FA in DAG tended to decrease
on d 3 owing to the lowered proportion of all polyunsaturated FA of n−6 and n−3 series. These results demonstrate that the
developmental decrease in PKC activity and expression in the rat myocardium is not linear and that subcellular localization
of the enzyme exhibits isoform-specific day-by-day changes during the early postnatal period. These changes are compatible
with the view that PKC signaling may be involved in the control of a rapid switch of myocardial growth pattern during the
first week of life. 相似文献
92.
OVARIOLE TYPES AND THE PHYLOGENY OF HEXAPODS 总被引:5,自引:0,他引:5
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Two monospecific genera of marine benthic dinoflagellates, Adenoides and Pseudadenoides, have unusual thecal tabulation patterns (lack of cingular plates in the former; and no precingular plates and a complete posterior intercalary plate series in the latter) and are thus difficult to place within a phylogenetic framework. Although both genera share morphological similarities, they have not formed sister taxa in previous molecular phylogenetic analyses. We discovered and characterized a new species of Pseudadenoides, P. polypyrenoides sp. nov., at both the ultrastructural and molecular phylogenetic levels. Molecular phylogenetic analyses of SSU and LSU rDNA sequences demonstrated a close relationship between P. polypyrenoides sp. nov. and Pseudadenoides kofoidii, and Adenoides and Pseudadenoides formed sister taxa in phylogenetic trees inferred from LSU rDNA sequences. Comparisons of morphological traits, such as the apical pore complex (APC), demonstrated similarities between Adenoides, Pseudadenoides and several planktonic genera (e.g. Heterocapsa, Azadinium and Amphidoma). Molecular phylogenetic analyses of SSU and LSU rDNA sequences also demonstrated an undescribed species within Adenoides. 相似文献
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William G. Breed Serica Tan Chrisopher M. Leigh Ken P. Aplin Katerina Dvorakova‐Hortova Harry D.M. Moore 《Journal of morphology》2011,272(7):883-889
This study describes the morphology of the spermatozoon from the cauda epididymidis of representative members of two squirrel subfamilies, the Sciurinae and Callosciurinae, as determined by fluorescent, scanning, and transmission electron microscopy. All species examined possess a massive apical segment of the sperm acrosome. It varied markedly in the extent of its caudal flexion but was always much larger, and more complex, than that of the spermatozoon of most other rodents so far documented, although somewhat similar to that of some hystricomorph species. Because this sperm form appears to be present within at least two of the three major living clades of Rodentia, it is possible that it is the ancestral condition within this mammalian order. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc. 相似文献
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Hyperthermia is a proven teratogen, inducing malformations and embryonic death in humans as well as in laboratory animals. The aim of our study was to define temperatures that are teratogenic after short-term exposure (from 2 to 24 h) on embryonic days 1–7 and to detect critical periods for the origin of structural defects in the chick embryo. Hyperthermia of 41 °C was not embryotoxic, temperatures from 42 to 44 °C induced malformations and embryonic death, while nearly all embryos died even after the shortest exposures to 45 or 46 °C. Among the wide spectrum of observed malformations, only ventricular septal defect (VSD) and caudal regression syndrome (CRS) were present at frequencies significantly different from those seen in controls. 相似文献