Implantation, early placentation, and the chronology of embryogenesis in Tupaia belangeri

Kuhn, Hans-Jürg; Schwaier, A

doi:10.1007/bf00519135

Cited by 34 publications

(21 citation statements)

References 10 publications

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“…It is advisable to keep the family Tupaiidae as a separate taxon beside the lipotyphlous Insectivora and the Macroscelididae and not to include it in the classification of primates, although the total organization of the family may serve as a clear model of ancestral primates. The exceptional position of the Tupaiidae is based on new findings of the early ontogenesis (Kuhn and Schwaier, 1973;Luckett, 1974) and the biology of behavior (Holst, 1969;Martin, 1972). 2.…”

Section: Discussionmentioning

confidence: 98%

The Development of the Chondrocranium in Primates

Starck

1975

Phylogeny of the Primates

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Section: Discussionmentioning

confidence: 98%

The Development of the Chondrocranium in Primates

Starck

1975

Phylogeny of the Primates

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“…Detailed descriptions of the tree shrew Tupaia belangeri (average gestation period 43.7 days; Kuhn and Schwaier, 1973), of the animals from our collection, and of the preparation procedures used in our studies have been provided by Knabe et al (2007, and references therein). Pregnant females were obtained from the former colony of the Battelle-Institute, Frankfurt/Main (Dr. Anita Schwaier), and from the German Primate Center (DPZ), Göttingen.…”

Section: Materials and Methods Animalsmentioning

confidence: 99%

Diversity in mammalian chiasmatic architecture: Ipsilateral axons are deflected at glial arches in the prechiasmatic optic nerve of the eutherian Tupaia belangeri

Knabe

Washausen

Happel

et al. 2008

J of Comparative Neurology

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Permanent ipsilaterally projecting axons approach the chiasmatic midline in rodents but are confined to lateral parts of the optic chiasm in marsupials. Hence, principally different mechanisms were thought to underlie axon pathway choice in eutherian (placental) and marsupial mammals. First evidence of diversity in eutherian chiasmatic architecture came from studies in the newborn and adult tree shrew Tupaia belangeri (Jeffery et al. [1998] J. Comp. Neurol. 390:183-193). Here, as in marsupials, ipsilaterally projecting axons do not approach the midline. The present study aims to clarify how the developing tree shrew chiasm is organized, how glial cells are arranged therein, and the extent to which the tree shrew chiasm is similar to that of marsupials or other eutherians. By using routinely stained serial sections as well as immunohistochemistry with antibodies against glial fibrillary acidic protein, vimentin, and medium-molecular-weight neurofilament protein, we investigated chiasm formation from embryonic day 18 (E18) to birth (E43). From E22 onward, ipsilaterally projecting axons diverged from contralaterally projecting axons in prechiasmatic parts of the optic nerve. They made sharp turns when arriving at glial arches found at the transition from the optic nerve to the chiasm. Thus, during the ingrowth period of axons, Tupaia belangeri and marsupials have specialized glial arrays in common, which probably help to deflect ipsilaterally projecting axons to lateral parts of the chiasm. Our observations provide new evidence of diversity in eutherian chiasmatic architecture and identify Tupaia belangeri as an appropriate animal model for studies on the mechanisms underlying axon guidance in the developing chiasm of higher primates.

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“…In Tupaia, the average gestation period is 43.7 days (Kuhn and Schwaier 1973). Young Tupaia usually open their eyes between day 14 and 16 postnatally and leave their nest around day 21.…”

Section: Methodsmentioning

confidence: 99%

The earliest invasion of macrophages into the developing brain and eye of the tree shrew Tupaia belangeri

Knabe¹,

Kuhn²

1999

Anatomy and Embryology

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The earliest occurrence of macrophages was investigated in the brain and optic anlagen of the tree shrew Tupaia belangeri. Nineteen serially sectioned embryos, belonging to five phases of programmed neuroepithelial cell death previously found during optic cup formation, were used. Macrophages were identified by structural criteria and by labelling with the lectin Griffonia simplicifolia I-B(4). Macrophages, most probably derived from the yolk sac, are present in the perineural vessels of the phase 1 embryo (V-shaped optic evagination). Within this compartment, their number increases up to phase 4 (advanced invagination) and drops during phase 5. This first wave of macrophages is followed by a second one occurring within the perineural mesenchyme and within the neuroepithelium of the brain and eyes from phase 3 onwards. In the phase 4 embryos, a considerable rise in the number of intraventricular macrophages is noted. During phase 5 (far advanced invagination), marked vascularization of the brain starts, and a peak of macrophages is noted in the neuroepithelium and in the ventricular lumen of the brain. This spatiotemporal pattern suggests that, in Tupaia, the earliest macrophages are simultaneously shifted from perineural vessels into the neuroepithelial walls of the developing brain and, at earlier stages than previously described in other vertebrate species, of the eye anlagen.

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Implantation, early placentation, and the chronology of embryogenesis in Tupaia belangeri

Cited by 34 publications

References 10 publications

The Development of the Chondrocranium in Primates

The Development of the Chondrocranium in Primates

Diversity in mammalian chiasmatic architecture: Ipsilateral axons are deflected at glial arches in the prechiasmatic optic nerve of the eutherian Tupaia belangeri

The earliest invasion of macrophages into the developing brain and eye of the tree shrew Tupaia belangeri

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