The Central Nervous Control of Colour Change in the Minnow (Phoxinus Phoxinus L.)

1971 ◽  
Vol 54 (1) ◽  
pp. 83-91
Author(s):  
MICHAEL J. GENTLE
Keyword(s):  
Optic Nerve ◽  
Optic Tectum ◽  
Posterior Part ◽  
Colour Change ◽  
Complete Removal ◽  
The Other ◽  
Nervous Control ◽  
Phoxinus Phoxinus ◽  
External Conditions

1. The colour of the minnow Phoxinus phoxinus L. and its ability to undergo colour change were studied after partial and complete blinding. The blinding was accomplished either by section of the optic nerve or by tectal ablation. 2. Following bilateral section of the optic nerve the blinded minnows darken. After the initial darkening, half of the fish pale and the other half remain dark. 3. The colour of the fish blinded by bilateral section of the optic nerve could not be affected by external conditions. 4. Following complete removal of the optic tectum the fish at first paled, but after 24 h they darkened to very variable tints. 5. Unilateral section of the optic nerve coupled with unilateral tectal removal on the same or opposite side did not affect the ability of the fish to change colour. 6. The bilateral removal of the anterior tectum from a blinded darkened fish did not affect its colour. 7. The bilateral removal of the posterior tectum of a darkened fish caused maximal pallor. 8. By a series of lesions an area in the dorsal posterior part of the optic tectum was found to cause darkening in the blinded fish because following its removal the fish paled. 9. It is suggested that the fibres from the tectum may act by exciting or inhibiting the neurones of the paling centre in the anterior medulla.

The Central Nervous Control of Colour Change in the Minnow (Phoxinus Phoxinus L.)

1971 ◽  
Vol 54 (1) ◽  
pp. 93-102
Author(s):  
MICHAEL J. GENTLE
Keyword(s):  
Optic Tectum ◽  
Colour Change ◽  
The Other ◽  
Dorsal Part ◽  
Nervous Control ◽  
Phoxinus Phoxinus ◽  
Normal Fish

1. A series of ablations were carried out in the optic tectum of the minnow, Phoxinus phoxinus, in order to investigate its importance in colour change. 2. The presence of the anterior or posterior tectum alone one on or both sides caused persistent pallor in normal fish. 3. The presence of the anterior tectum on one side and the posterior on the other enabled the fish to adapt chromatically to its background. 4. Small bilateral removals from the dorsal part of the optic tectum did not effect colour change. Larger removals from the dorsal tectum reduced the extent of change and still larger removals caused the fish to pale on all backgrounds.

Erratum

1971 ◽  
Vol 54 (1) ◽  
pp. 1-1
Author(s):  
GENTLE M. J.
Keyword(s):  
Colour Change ◽  
Nervous Control ◽  
Phoxinus Phoxinus

The central nervous control of colour change in the minnow (Phoxinus phoxinus L.) Discussion, line 4: Delete ‘unlike the fish used by the Dijkgraaf’

Electrical Activity in the Optic Tectum and Colour Change in the Minnow (Phoxinus Phoxinus L.)

1971 ◽  
Vol 55 (3) ◽  
pp. 641-649
Author(s):  
MICHAEL J. GENTLE
Keyword(s):  
Electrical Activity ◽  
Optic Tectum ◽  
High Frequency ◽  
Colour Change ◽  
Phoxinus Phoxinus ◽  
Black Background ◽  
High Frequency Activity

1. The electrical activity of the optic tectum was recorded from the minnow under various conditions to investigate its relationship to colour change. 2. The superficial E.E.G. was found to consist of two rhythms a 6-14 Hz (20-112 V) and a 18-24 Hz (6-18 µV). 3. When the fish were deeply anaesthetized the E.E.G. was reduced virtually to nothing. 4. Almost no activity was present in the optic tectum 30 min after bilateral blinding. There was an increase in activity after 5 h and this continued for 5 or more days but never returned to normal. 5. In darkness the activity of the superficial E.E.G. first increased and then decreased, and when the eyes were re-exposed to light the activity increased again. 6. The E.E.G. patterns were recorded and analysed from various depths and positions in the optic tectum during background reversal. In the stratum plexiformeet fibrosum externum, plexiforme internum and griseum internum no changes were observed. In the stratum fibrosum profundum and griseum periventriculare an increase in the high-frequency activity of approximately 10 Hz was observed on a black background.

The discontinuous visual projections on the Xenopus optic tectum following regeneration after unilateral nerve section

Development ◽  
1986 ◽  
Vol 94 (1) ◽  
pp. 121-137
Author(s):  
D. J. Willshaw ◽  
R. M. Gaze
Keyword(s):  
Optic Nerve ◽  
Horseradish Peroxidase ◽  
Optic Tectum ◽  
Small Proportion ◽  
The Other ◽  
Nerve Transection ◽  
Nerve Section ◽  
Retinotectal Projections ◽  
Uniform Background ◽  
Whole Mounts

The establishment of retinotectal projections following transection of one optic nerve in developing Xenopus has been investigated. Between 3 weeks and 11 months after the operation, the nerve fibre tracer horseradish peroxidase (HRP) was applied to either the operated or the unoperated nerve, and the brains were prepared for examination as whole mounts. In most cases fibres from the operated nerve innervated both tecta, with the result that one tectum was doubly innervated and one tectum singly innervated. Two months after transection of the optic nerve in tadpole life, between stages 50 and 54, this nerve usually made a uniform projection on the contralateral tectum and a striped projection on the ipsilateral, doubly innervated, tectum. The projection made by the unoperated nerve on this tectum was a similar pattern of stripes, which ran generally rostrocaudally. Two months after transection of the optic nerve of newly metamorphosed animals, the projection formed by the operated nerve on the doubly innervated tectum was usually a pattern of spots or spots mixed together with stripes in no particular orientation superimposed on a roughly uniform background. In a small number of cases the projections made by the same nerve on the two tecta were approximately complementary; that is, the presence of label on one tectum corresponded with its absence on the other tectum. The results are examined in the context of the development of the retina and of the tectum. It is suggested that the consistently oriented stripes which result from nerve transection at a stage at which only a small proportion of the retinal fibres had reached the tectum are formed by the interaction of two equally matched sets of developing fibres, stripe orientation being determined by the mode of growth of the optic tectum. The formation of patterns of spots or spots mixed together with stripes following nerve transection after the end of the main phase of tectal histogenesis, and when 50 % of the optic fibres had already reached the tectum, is attributed to an unequal competition between the two sets of fibres.

scholarly journals The Pigmentary Effector System IV.--A Further Contribution to the Role of Pituitary Secretion in Amphibian Colour Response

1924 ◽  
Vol 1 (2) ◽  
pp. 249-270
Author(s):  
LANCELOT T. HOGBEN
Keyword(s):  
Colour Change ◽  
Complete Removal ◽  
Posterior Lobe ◽  
Pituitary Extract ◽  
Nervous Control ◽  
Normal Individuals ◽  
Effector System ◽  
Physiologically Active Substances ◽  
Normal Colour ◽  
Pituitary Secretion

1. The contracted melanophores of both Anura (frogs and toads) and Urodela (salamanders) react by maximal expansion to pituitary extract; the active substance in the latter does not appear to be confined invariably to the posterior lobe of the mammalian gland. A positive melanophore response was obtained from the gland of a human abortus in the fourth month. 2. The removal of the whole pituitary gland may be accomplished in Urodele larvaæ (Amblystoma tigrinum) at any age (nine months to four years) without impairing their viability. After complete removal of the pituitary in Urodele larvæ, as in adult and larval Anura, the melanophores remain contracted and a state of permanent pallor ensues. The normal colour resulting from melanophore expansion can be re-established by injection of pituitary extract; but such animals regain pallor, although exposed to conditions in which melanophore expansion invariably occurs in normal individuals. 3. It is legitimate to conclude that pituitary secretion is the main factor in regulating the chromatic function throughout the Amphibia as a class. Fluctuating pituitary secretion in correlation with those conditions that evoke colour response in the frog (cf. the third paper of this series) provides a satisfactory basis for the interpretation of all the accredited bionomic data concerning colour response in adult Amphibia. Possibly adrenal secretion or some auxiliary mechanism plays a subsidiary part; but there are no satisfactory grounds for believing that nervous agencies directly influence amphibian melanophores; and there is reason to believe that even if amphibian melanophores are directly innervated, nervous control is not significant to the normal rhythm of colour change. 4. The study of amphibian colour response provides evidence not only of the presence of physiologically active substances in the pituitary, but functional activity of the gland in the intact animal. It does not appear, however, that the interpretation of colour response here put forward for Amphibia can be extended to Reptiles and Fishes.

Suitability of forms of preparing seeds of Dalbergia miscolobium Benth for exposure to the tetrazolium test / Adequação das formas de preparação de sementes de Dalbergia miscolobium Benth para exposição ao teste de tetrazolium

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Juliana Martins de Mesquita Matos ◽  
Rosana De Carvalho Cristo Martins ◽  
Valéria Regina Bellotto ◽  
Lilian Gomes da Silva Rocha ◽  
Eloiza Aparecida Barbosa ◽  
...  
Keyword(s):  
Endangered Species ◽  
Filter Paper ◽  
Federal District ◽  
Complete Removal ◽  
Sensu Stricto ◽  
The Other ◽  
Distrito Federal ◽  
Viable Seeds ◽  
Range Test ◽  
Tetrazolium Test

Dalbergia miscolobium or Jacarandá do Cerrado is a species of legume in the Fabaceae family. It occurs in the sensu stricto Cerrado and in the dystrophic cerradão. It shows potential for landscaping and for recovering damaged areas. It is an endangered species and therefore is protected by the law that prevents cut in areas of the Federal District (Decree No. 14.783/93). The purpose of this study was to determine the best procedure to prepare seeds of Dalbergia miscolobium to assess viability in the tetrazolium test. We carried out the following treatments: i) hydration on filter paper at 25 ° C, ii) hydration on filter paper at 25 ° C followed by a cut in the tegument and iii) hydration on filter paper at 25 ° C followed bya complete removal of the tegument. The results were analyzed using analysis of variance and the Tukey range test. The analyzes showed that the best procedure to prepare seeds of Dalbergia miscolobium is the treatment in which there is a hydration followed by the complete removal of the integument. Where 78% of the seeds showed uniform staining, indicating that the seeds analyzed are of good quality. The other treatments, hydration and hydration followed by cutting, showed respectively 35% and 41% of viable seeds. RESUMO A Dalbergia miscolobium ou Jacarandá do Cerrado é uma espécie de leguminosa da família Fabaceae. Ocorre no sentido stricto Cerrado e no cerradão distrófico. Possui potencial para paisagismo e para recuperar áreas degradadas. É uma espécie ameaçada de extinção e, portanto, está protegida pela lei que previne o corte em áreas do Distrito Federal (Decreto 14.783 / 93). O objetivo deste estudo foi determinar o melhor procedimento de prepararação das sementes de Dalbergia miscolobium para serem submetidas à análise de viabilidade pelo teste de tetrazólio. Foram realizados os seguintes tratamentos: i) hidratação em papel de filtro a 25 ° C, ii) hidratação em papel de filtro a 25 ° C seguida de um corte no tegumento e iii) hidratação em papel de filtro a 25 ° C seguido de remoção completa do tegumento. Os resultados foram analisados utilizando-se a análise de variância e o teste de médias de Tukey. As análises mostraram que o melhor procedimento para preparar sementes de Dalbergia miscolobium é o tratamento em que há uma hidratação seguida pela remoção completa do tegumento, onde 78% das sementes apresentaram coloração uniforme, indicando que as sementes analisadas são de boa qualidade. Os demais tratamentos, hidratação e hidratação seguida de corte, mostraram respectivamente 35% e 41% de sementes viáveis.

Specification of retinotectal connexions during development of the toad Xenopus laevis

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 77-92
Author(s):  
S. C. Sharma ◽  
J. G. Hollyfield
Keyword(s):  
Xenopus Laevis ◽  
Ganglion Cell ◽  
Retinal Ganglion Cells ◽  
Optic Tectum ◽  
Ganglion Cells ◽  
The Other ◽  
Retinal Ganglion ◽  
Visual Projection ◽  
Series Of Experiments ◽  
The Right

The specification of central connexions of retinal ganglion cells was studied in Xenopus laevis. In one series of experiments, the right eye primordium was rotated 180° at embryonic stages 24–32. In the other series, the left eye was transplanted into the right orbit, and vice versa, with either 0° or 180° rotation. After metamorphosis the visual projections from the operated eye to the contralateral optic tectum were mapped electrophysiologically and compared with the normal retinotectal map. In all cases the visual projection map was rotated through the same angle as was indicated by the position of the choroidal fissure. The left eye exchanged into the right orbit retained its original axes and projected to the contralateral tectum. These results suggest that retinal ganglion cell connexions are specified before stage 24.

scholarly journals The lantern shark's light switch: turning shallow water crypsis into midwater camouflage

2010 ◽  
Vol 6 (5) ◽  
pp. 685-687 ◽  
Author(s):  
Julien M. Claes ◽  
Jérôme Mallefet
Keyword(s):  
Shallow Water ◽  
Deep Sea ◽  
Light Emission ◽  
Colour Change ◽  
Hormonal Control ◽  
Nervous Control ◽  
Luminous Bacteria ◽  
Physiological Colour Change ◽  
Physiological Suppression

Bioluminescence is a common feature in the permanent darkness of the deep-sea. In fishes, light is emitted by organs containing either photogenic cells (intrinsic photophores), which are under direct nervous control, or symbiotic luminous bacteria (symbiotic photophores), whose light is controlled by secondary means such as mechanical occlusion or physiological suppression. The intrinsic photophores of the lantern shark Etmopterus spinax were recently shown as an exception to this rule since they appear to be under hormonal control. Here, we show that hormones operate what amounts to a unique light switch, by acting on a chromatophore iris, which regulates light emission by pigment translocation. This result strongly suggests that this shark's luminescence control originates from the mechanism for physiological colour change found in shallow water sharks that also involves hormonally controlled chromatophores: the lantern shark would have turned the initial shallow water crypsis mechanism into a midwater luminous camouflage, more efficient in the deep-sea environment.

scholarly journals A Conservative Approach to a Peripheral Ameloblastoma

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Rocco Borrello ◽  
Elia Bettio ◽  
Christian Bacci ◽  
Marialuisa Valente ◽  
Stefano Sivolella ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Soft Tissues ◽  
Complete Removal ◽  
The Other ◽  
Conservative Approach ◽  
Choice Of Treatment ◽  
Long Term Follow Up ◽  
One Year

Peripheral Ameloblastoma (PA) is the rarest variant of ameloblastoma. It differs from the other subtypes of ameloblastoma in its localization: it arises in the soft tissues of the oral cavity coating the tooth bearing bones. Generally, it manifests nonaggressive behavior and it can be treated with complete removal by local conservative excision. In this study we report a case of PA of the maxilla in a 78-year-old female patient and we describe the four different histopathological patterns revealed by histological examination. After local excision and diagnosis, we planned a long term follow-up: in one year no recurrence had been reported. The choice of treatment is illustrated in Discussion.

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