Cement gland as the adhesion organ in Xenopus laevis embryos

Pshennikova, E. S.; Voronina, A. S.

doi:10.1134/s1062360411040096

Cited by 2 publications

(1 citation statement)

References 99 publications

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“…The putative synapomorphic delay in the bilateral division of the adhesive gland in the ancestor of Ceratophrys pends confirmation after the remaining species of the genus are examined. The late regression of these glands is puzzling, but the concomitant late regression of hatching glands that develop from the same prospective tissue (Pshennikova & Voronina, ) suggests that the timing may reflect a developmental constraint unrelated to functional considerations.…”

Section: Discussionmentioning

confidence: 99%

Embryonic ontogeny of three species of Horned Frogs, with a review of early development in Ceratophryidae

Grosso

Baldo

Costa

et al. 2019

Journal of Morphology

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Horned Frogs of the family Ceratophryidae are conspicuous anurans represented by three endemic South American genera. Most ceratophryids inhabit semiarid environments, but three species of Ceratophrys occupy tropical or temperate humid areas. Several morphological and behavioral characters of larvae and adults are conserved across the family. Based on examination of specimens and accounts in the literature, the embryonic development of C. ornata, C. cranwelli, and the monotypic genus Chacophrys are described and compared with that of species of Lepidobatrachus. Ceratophryid embryos share a suite of morphological features and heterochronic shifts during development. Most features, such as gill structure, ciliation, early hatching, and precocious differentiation of the gut and hind limbs, are shared by all the species regardless the differences in the habitats that occupy. This is consistent with previous observations of some adult characters, and likely supports the hypothesis of an early diversification of ceratophryids in semiarid environments. Other embryonic features, such as the morphology and ontogeny of the oral disc and digestive tract, are correlated with larval feeding habits and vary within the family. The evolutionary and ecological significance of some conserved characters (e.g., gastrulation pattern, Type‐A adhesive glands) and other taxon‐specific features (e.g., nasal appendix) remain to be explored in the group.

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Section: Discussionmentioning

confidence: 99%

Embryonic ontogeny of three species of Horned Frogs, with a review of early development in Ceratophryidae

Grosso

Baldo

Costa

et al. 2019

Journal of Morphology

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Glycine blocks the regulatory volume response of mouse oocytes to hypoosmotic stress

Pogorelova

Голиченков

Pogorelova³

et al. 2012

Dokl Biochem Biophys

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In discussing the causes of the compensatory response to hypoosmotic stress (regulatory volume decrease, RVD), the induced transport of osmolytes from the cell through the volume sensitive organic osmolyte anion channel (VSOAC) is considered first [1]. A Сl -channel with similar pharmacological prop erties, coupled to nonspecific release of amino acids, was found on zygote and oocyte membranes [2,3]. The interest to the involvement of glycine in osmotic regulation is caused by the fact that a specific trans porter, GLYT1, was found on the membrane of mouse zygote and two cell embryo [4]. This active Na + (Cl -) dependent transport of glycine was later found in mature oocytes at the stage of MII development [5]. GLYT1 provides transmembrane transport of glycine in both directions [6], which suggests the possibility of its involvement in RVD. However, the role of glycine in the compensatory response of an embryonic cell to hypotonic stress remains poorly understood [7], and only single papers are devoted to RVD regulation in the mature oocytes, the immediate precursor of early embryogenesis [3].This study shows that glycine present at a physio logical concentration (10 mM) in the extracellular space blocks the development of RVD in the oocyte. The effect is similar to the non osmotic effect of ATP, an inhibitor of VSOAC. A decrease in the concentra tion of the amino acid to the submillimolar level does not recover the compensatory reaction. This fact sug gests that oocytes have mechanisms of glycine medi ated regulation of the osmotic response.Isolated mouse MII oocytes were prepared as described in [8]. The volume of a single oocyte (Fig. 1) was measured by quantitative laser scanning micros copy (QLSM). The procedure of sample preparation for QLSM and the details of measurement of spatial characteristics were published earlier [9, 10].The obtained kinetics of the change in the cell vol ume in the oocyte in the course of hypoosmotic stress is shown in Fig. 2.In the absence of glycine, RVD is triggered in response to hypoosmotic stress, when the initial swell ing is accompanied by an adaptive response, as a result of which the cell tends to recover the intact volume (Fig. 2). Earlier, the authors of [5] demonstrated the presence of GLYT1 on the membrane of mouse oocyte MII. This glycine transporter is reversible, i.e., it per forms active transmembrane transport of amino acids in both directions, which is due to the gradient of sodium ions on the cell membrane. Hypothetically, the driving force in the case of the oocyte may be a rel atively high level of Na + , which was detected, for example, in the frog egg [11]. Unfortunately, it is not yet possible to repeat such measurements in the mouse oocyte. As a result, GLYT1, which pumps glycine from the cytoplasm to the extracellular space, may be involved in RVD. In this case, the intracellular con centration of glycine does not necessarily change, because the decrease in the cell volume compensates for the on mass decrease in the content of the amino acid.Note that th...

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Cement gland as the adhesion organ in Xenopus laevis embryos

Cited by 2 publications

References 99 publications

Embryonic ontogeny of three species of Horned Frogs, with a review of early development in Ceratophryidae

Embryonic ontogeny of three species of Horned Frogs, with a review of early development in Ceratophryidae

Glycine blocks the regulatory volume response of mouse oocytes to hypoosmotic stress

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