Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 210 (2000), S. 55-63 
    ISSN: 1432-041X
    Keywords: Key words Cell lineages ; Ascidian development ; Metamorphosis ; Horseradish peroxidase injection ; Endoderm differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Cell lineages during ascidian embryogenesis are invariant. Developmental fates of larval mesodermal cells after metamorphosis are also invariant with regard to cell type of descendants. The present study traced developmental fates of larval endodermal cells after metamorphosis in Halocynthia roretzi by labeling each endodermal precursor blastomere of larval endoderm. Larval endodermal cells gave rise to various endodermal organs of juveniles: endostyle, branchial sac, peribranchial epithelium, digestive organs, peripharyngeal band, and dorsal tubercle. The boundaries between clones descended from early blastomeres did not correspond to the boundaries between adult endodermal organs. Although there is a regular projection from cleavage stage and larval stage to juvenile stage, this varies to some extent between individuals. This indicates that ascidian development is not entirely deterministic. We composed a fate map of adult endodermal organs in larval endoderm based on a statistical analysis of many individual cases. Interestingly, the topographic position of each prospective region in the fate map was similar to that of the adult organ, indicating that marked rearrangement of the positions of endodermal cells does not occur during metamorphosis. These findings suggest that fate specification in endoderm cells during metamorphosis is likely to be a position-dependent rather than a deterministic and lineage-based process.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-041X
    Keywords: Key words Ascidian embryos ; Notch homologue ; CNS ; Equivalence group ; Cell interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We describe here the primary structure of HrNotch, an ascidian homologue of the Drosophila neurogenic gene Notch. HrNotch transcripts encode a protein of 2352 amino acids and share the principal features of the Notch gene family: extracellular epidermal growth factor (EGF)-like repeats, three Notch/Lin-12 repeats and six intracellular ankyrin repeats. Yet ascidian Notch contains only 33 EGF repeats in the putative extramembrane domain and specifically lacks the three EGF-like repeats. In situ hybridization shows that maternal HrNotch mRNA is distributed uniformly in the cytoplasm of the unfertilized egg. During cleavage, maternal HrNotch transcripts are ubiquitous in the ectoderm cells of the animal hemisphere, which contain less yolk granules. During gastrulation, maternal transcripts persist in most ectoderm lineage cells. Zygotic expression of HrNotch seems to start at the neural plate stage in both a-line cells (descendants of anterior-animal blastomeres) of the dorsal neuroectoderm and b-line cells (descendants of the posterior-animal blastomeres) that comprise the neural fold. Following this stage, transcripts are most evident in the descendants of these cells, that is, the brain lineage cells, precursors of a larval adhesive organ, and dorsal part of the nerve cord (roof plate). Brain lineage cells include the precursors of sensory pigment cells that are known to comprise an equivalence group in ascidian embryos. During tail elongation, transcripts disappear. Predominant expression of HrNotch in epidermal and neural cells is a common feature of chordate Notch genes. Furthermore, the timing of HrNotch expression in sensory pigment cell precursors suggests involvement in the determinative events in the sensory pigment cell equivalence group.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 153 (1994), S. 702-702 
    ISSN: 1432-1076
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 2034-2038 
    ISSN: 0392-6737
    Keywords: Photoluminescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si sono fatte misurazioni degli spettri di fotoluminescenze e di eccitazione luminescenza di ZnSiP2 a 4.2 K e si sono ottenuti due risultati. Uno è l'osservazione di una nuova linea netta di emissione a 1.980 eV, dovuta all'eccitone legato associato col gap pseudodiretto. L'altro è l'osservazione di un'altra nuova serie di linee di assorbimento nello spettro di eccitazione di luminescenza di una linea di emissione a 1.984 eV, oltre a quelle riportate in precedenza. Questi risultati indicano che in ZnSiP2 si verificano transizioni radiative sia per gap indiretti che per gap pseudodiretti.
    Abstract: Резюме При 4.2 К проведены измерения спектров фотолюминесцендии и спектры возбуждения люминесценцией в ZnSiP2 и получено два результата. Один результат представляет наблюдение новой резкой линии излучения при 1.980 эВ. обусловленной связанным экситоном, ассоциированным с псевдопрямым интервалом. Второй результат предсталяет наблюдение новых линий поглошения в спектре возбуждения люминесценцией линии излучения при 1.984. эВ. Эти результаты указывают, что в ZnSiP2 радиационные переходы происходят при косвенных и псевдопрямых интервалах.
    Notes: Summary Measurements of photoluminescence and luminescence excitation spectra of ZnSiP2 have been performed at 4.2K and two results were obtained. One is the observation of a new sharp emission line at 1.980 eV, due to the bound exciton associated with the pseudodirect gap. The other is the observation of another new series of absorption lines in the luminescence excitation spectrum of an emission line, at 1.984 eV, in addition to those reported previously. These results indicate that in ZnSiP2 radiative transitions occur at both the indirect and the pseudodirect gaps.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cutaneous pathology 11 (1984), S. 0 
    ISSN: 1600-0560
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Nevic corpuscle in the pigmented nevus was studied under light microscopy in comparison with Meissner corpuscle of the human sole skin in order to determine its ontogenesis. No nerve fibers within nevic corpuscle but coiled fibers in Meissner corpuscle could be demonstrated by Bodian slain. Presence of S-100 protein in the pigmented nevus and Meissner corpuscle was observed under light microscopy utilizing peroxidase-antiperoxidase immunohistochemical staining. S-IOU protein was more evident in nevic corpuscles than in Types A and B intradermal nevus cells. Meissner corpuscle showed moderate stainability for S-100 protein. Ultrastructural study revealed that the nevic corpuscle was composed of the laminated cells with flattened cytoplasmic processes but lacked peripheral nerve endings such as axons, characteristically shown in Meissner corpuscle. No melanogenic activity of nevic corpuscle was observed. These morphological and histochemical findings of nevic corpuscle did not enable us lo give definite conclusion on its ontogenesis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 202 (1994), S. 1054-1059 
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Carbohydrate Research 180 (1988), S. 35-42 
    ISSN: 0008-6215
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Free Radical Biology and Medicine 15 (1993), S. 101-104 
    ISSN: 0891-5849
    Keywords: Cyclo-oxygenase ; Free radicals ; Lipoxygenase ; Rabbit platelets ; Reactive oxygen species
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physics Letters A 83 (1981), S. 446-448 
    ISSN: 0375-9601
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Analytica Chimica Acta 139 (1982), S. 219-227 
    ISSN: 0003-2670
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...