The origin of the abnormalities of the inner ear in dreher mice

Development ◽  
1964 ◽  
Vol 12 (4) ◽  
pp. 727-733
Author(s):  
M. S. Deol
Keyword(s):  
Inner Ear ◽  
Neural Tube ◽  
Otic Vesicle ◽  
Stages Of Development ◽  
Early Stages

The anatomy and development of the inner ear in dreher (dr/dr) mice has been described in detail by Fischer (1956, 1957, 1958). The abnormalities first appear at the 10-day stage, and consist in the retarded development of Anson's folds (Anson, 1934). In the adult labyrinth the cochlear tube is shorter than normal and not so tightly coiled, the scala media opens widely into the sacculus without the intervention of a ductus reuniens, and the sacculus similarly opens into the utriculus without saccular and utricular ducts. These abnormalities may be viewed as signs of an incomplete or weak differentiation of the otic vesicle. As it is known from experiments on amphibians and birds that the differentiation of the otic vesicle into a multi-chambered labyrinth depends on the inductive influence of the neural tube (Harrison, 1945; Detwiler & van Dyke, 1950; Yntema, 1950), and as there is some evidence that this is also true of mammals (Deol, 1964), it was thought that an examination of the neural tube in dreher mice in early stages of development would be desirable.

scholarly journals The probable mode of gene action in the circling mutants of the mouse

1966 ◽  
Vol 7 (3) ◽  
pp. 363-371 ◽  
Author(s):  
M. S. Deol
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Inner Ear ◽  
Neural Tube ◽  
Gene Action ◽  
Circumstantial Evidence ◽  
Otic Vesicle ◽  
The Central Nervous System

A close examination of reports on circling mutants of the mouse suggested that the commonly held view that the abnormalities of the inner ear are responsible for the waltzing syndrome was probably without foundation. It was thought that a study of kinky (Fuki/+) mice might resolve the doubt, because this mutant has the widest range of abnormalities of the inner ear and behaviour. The results showed that correlation between the two types of abnormalities, although high, was far from complete. This is interpreted as signifying that they are related collaterally rather than lineally. It is argued that they both originate in some primary abnormality of the central nervous system, and circumstantial evidence is presented in support of this argument. It is further suggested that the mode of gene action is essentially similar in all circling mutants, that is the abnormalities of the inner ear are consequent on some early abnormality of the neural tube and the ganglia in the region of the otic vesicle.

scholarly journals The Effect of Benzimidazole on the Differentiation of Ectodermal Explants from the Gastrulae of Xenopus laevis

Development ◽  
1960 ◽  
Vol 8 (4) ◽  
pp. 396-404
Author(s):  
F. Billett ◽  
S. K. Brahma
Keyword(s):  
Xenopus Laevis ◽  
Neural Tube ◽  
Chick Embryos ◽  
Stages Of Development ◽  
Early Stages ◽  
General Kind ◽  
The Way

The treatment of amphibian and chick embryos during the early stages of development with small concentrations of benzimidazole, and some of its derivatives, results in the formation of abnormal embryos (Liedke, Engleman, & Graff, 1954; Waddington, Feldman, & Perry, 1955a; Billett & Perry, 1957 a, b). The gross effects produced by these substances are of a fairly general kind. Abnormal gastrulation, decomposition of neurulae, and microcephaly are produced in Amphibia. Rather less well-defined abnormalities, involving the head, neural tube, and somites, are seen in the chick. The way in which these abnormalities are produced is not known. The idea that benzimidazole acts simply as a purine anti-metabolite is not well founded (Slonimski, 1954). The work of Tamm and his colleagues (Tamm, Folkers, Shunk, & Horsfall, 1953; Tamm, 1958) has shown that benzimidazole and certain of its derivatives inhibit the growth of some viruses.

Comparative leaf development of aerial and aquatic growth forms of Myriophyllum aquaticum

Botany ◽  
2013 ◽  
Vol 91 (7) ◽  
pp. 421-430 ◽  
Author(s):  
M.D. Shafiullah ◽  
Christian R. Lacroix
Keyword(s):  
Apical Meristem ◽  
Epidermal Cells ◽  
The Other ◽  
Developmental Study ◽  
Growth Forms ◽  
Myriophyllum Aquaticum ◽  
Stages Of Development ◽  
Qualitative And Quantitative ◽  
Early Stages ◽  
Other Hand

Myriophyllum aquaticum (Vell.) Verdc. produces two morphologically different forms of leaves based on whether they are aerial or aquatic. The objective of this study was to determine whether there are any similarities or differences between these two growth forms during their early stages of development. A comparative developmental study of aerial and aquatic growth forms of M. aquaticum was conducted from a qualitative and quantitative perspective using a scanning electron microscope. The pattern of leaf and lobe initiation such as their origin and shape were similar in both growth forms until the fourth plastochron (stage P4). Differences between the two growth forms became evident from stage P5 onward, where a larger shoot apical meristem (SAM), elongated epidermal cells, shorter and slightly more numerous lobes, as well as the presence of appendage-like structures characterized aquatic growth forms. On the other hand, aerial growth forms had smaller SAM, bulb-like epidermal cells, and longer and slightly less numerous leaf lobes. Significant differences between growth forms were noted for parameters such as volume of SAM, length of terminal, first, and middle lobes, as well as the length from first to last lobes. The volume of the SAM of aquatic shoot tips was always greater than aerial forms. On the other hand, lobes of aerial forms were always longer than the aquatic counterpart during early stages of development. This study on the development of M. aquaticum shows that the aerial and aquatic growth forms diverge from their early stages of development.

XV. On the development of the parasitic isopoda

1878 ◽  
Vol 169 ◽  
pp. 505-521 ◽  
Keyword(s):  
The Body ◽  
The Other ◽  
Stages Of Development ◽  
Early Stages ◽  
Abdominal Appendages ◽  
Pair Of Antennae

The following paper contains an account of observations on the development of the species Cymothoa œstroides and C . parallela of Milne Edwards; but the forms of the young seem to show that several species are really included under these two names. In the early stages of development the only observable difference that exists between the embryos is one of size, but in the later stages they differ very markedly from each other in their external characters. From adult individuals answering the description of C . œstroides I have obtained four varieties of embryos: two with long antennae and two with short.* In the two former the first pair of antennae are but slightly longer than the head, while the second pair are longer than the body; the eyes are small. In one of the varieties thus characterised the abdominal appendages are fringed with long hairs (fig. 20), and in the other they are smooth.

The Effects of β-Mercaptoethanol on the Morphogenetic Movements of Amphibian Embryos

Development ◽  
1963 ◽  
Vol 11 (1) ◽  
pp. 155-166
Author(s):  
P. Malpoix ◽  
J. Quertier ◽  
J. Brachet
Keyword(s):  
Neural Tube ◽  
Tube Formation ◽  
Animal Pole ◽  
Morphogenetic Movements ◽  
Complete Development ◽  
Early Stages ◽  
Amphibian Embryos ◽  
Biological Specificity ◽  
Neural Tube Formation

The inhibition by β-mercaptoethanol of morphogenesis in amphibians, freshwater hydra, planarians and regenerating tadpoles, has already been reported by one of us (Brachet, 1958, 1959a, b, c). The present work provides a closer analysis of the biological specificity of j8-mercaptoethanol with regard to the different movements which produce gastrulation in amphibians: invagination, epiboly, convergent stretching and ingression. The main result, obtained with Pleurodeles, was that gastrulation is completely inhibited by M/100 β-mercaptoethanol. Lower concentrations (M/300) permit more complete development, but the resulting embryos are abnormal. β-Mercaptoethanol interferes with neural tube formation, but has less effect on the development of the notochord and the mesodermal somites. It was further noted that, when embryos are treated at very early stages (1–2 cells, young blastulae), the blastocoele seems to collapse and the ectoblast of the animal pole is deeply puckered.

Retinoid-binding protein distribution in the developing mammalian nervous system

Development ◽  
1990 ◽  
Vol 109 (1) ◽  
pp. 75-80 ◽  
Author(s):  
M. Maden ◽  
D.E. Ong ◽  
F. Chytil
Keyword(s):  
Nervous System ◽  
Retinoic Acid ◽  
Neural Crest ◽  
Motor Neurons ◽  
Neural Tube ◽  
Binding Protein ◽  
Sympathetic Ganglia ◽  
Retinol Binding Protein ◽  
Otic Vesicle ◽  
Protein Distribution

We have analysed the distribution of cellular retinol-binding protein (CRBP) and cellular retinoic acid-binding protein (CRABP) in the day 8.5-day 12 mouse and rat embryo. CRBP is localised in the heart, gut epithelium, notochord, otic vesicle, sympathetic ganglia, lamina terminalis of the brain, and, most strikingly, in a ventral stripe across the developing neural tube in the future motor neuron region. This immunoreactivity remains in motor neurons and, at later stages, motor axons are labelled in contrast to unlabelled sensory axons. CRABP is localised to the neural crest cells, which are particularly noticeable streaming into the branchial arches. At later stages, neural crest derivatives such as Schwann cells, cells in the gut wall and sympathetic ganglia are immunoreactive. An additional area of CRABP-positive cells are neuroblasts in the mantle layer of the neural tube, which subsequently appear to be the axons and cell bodies of the commissural system. Since retinol and retinoic acid are the endogenous ligands for these binding proteins, we propose that retinoids may play a role in the development and differentiation of the mammalian nervous system and may interact with certain homoeobox genes whose transcripts have also been localised within the nervous system.

The abnormalities of the inner ear in kreisler mice

Development ◽  
1964 ◽  
Vol 12 (3) ◽  
pp. 475-490
Author(s):  
M. S. Deol
Keyword(s):  
Inner Ear ◽  
Recessive Gene ◽  
Cresyl Violet ◽  
Otic Vesicle ◽  
Litter Mate ◽  
Abnormal Position ◽  
Sectioned Material

The recessive gene kreisler (symbol kr) was discovered by Hertwig (1942a), who later described its effects on behaviour (1942b) and the inner ear (1944, 1956). She found that it was possible to trace the anomalies of the ear back to 9-day embryos, when the otic vesicle can be seen to be situated in an abnormal position. The present study was aimed at discovering the cause of this abnormality, and at giving a fuller account of the later development of the ear. Material and Methods The particulars of the sectioned material are given in Table 1. Only litter-mate controls were used throughout. The embryos were fixed in Bouin's fluid, sectioned at 7½ or 10 μ, depending on their age, and stained with Ehrlich's haematoxylin and eosin. The older material was fixed in Witmaack's fluid or formalin, sectioned at 10 μ, and stained either the same way or with cresyl violet or Weil's iron haematoxylin.

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