共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
3.
Guy Vernet 《Cell and tissue research》1972,134(2):245-254
Résumé Lors de la régénération traumatique des yeux de Lineus ruber la différenciation biochimique des nouvelles cellules pigmentaires est séquentielle. On assiste à l'apparition successive des chaînes enzymatiques nécéssaires à la biosynthèse de porphyrine et de mélanine.Les études ultrastructurale et autoradiographique à haute résolution de ces phénomènes — montrent que la mélanisation s'opère au niveau d'organites cellulaires spécialisés (prémélanosomes, mélanosomes). La porphyrinogénèse se développe dans des vacuoles et organites d'origine golgienne qui participent également à la mélanogénèse.
Ultrastructure of photoreceptors in Lineus ruber (O. F. Müller)
Summary In Lineus ruber the biochemical differentiation of the new pigmentary cells is sequential during the reparative regeneration of the eyes. The enzymatic pathways for porphyrin and melanin biosynthesis appear successively.Ultrastructural and high resolution radioautography studies, show that melanization occurs in specialized organelles called premelanosomes, melanosomes and melanin granules. Prophyrogenesis occurs in Golgi vesicles which are also involved in melanogenesis.相似文献
4.
Abstract Presence of Rhodymenia delicatula P.J.L. Dangeard in the Mediterranean. - The presence of Rhodymenia delicatula P.J.L. Dangeard (Rhodophyta, Rhodymeniales) in the southern Thyrrhenian sea is reported. Both cystocarpic and tetrasporic individuals have been collected. Anatomical features of the reproductive structures, as well as the position of these on the thallus allowed the identification of this species formerly known for the Atlantic coasts of Morocco and British Isles. 相似文献
5.
Guy Vernet 《Cell and tissue research》1970,104(4):494-506
Summary The eyes of the Nemertean worm Lineus ruber are situated on the dorsal face of the animal in two lateral bands in front of the cerebral ganglia. There are 6 or 8 ocelli per animal enclosed in the cephalic parenchyme. They consist of a pigmented eyecup in which 50 photoreceptor cells are present. The photoreceptrice cells have:dendritic processes which are full of mitochondria, neurotubules, vacuoles and only one axial filament;a pericaryon with rough endoplasmic reticulum, a Golgi apparatus and few mitochondria.
Résumé Les yeux de la Némerte marine Lineus ruber sont situés sur la face dorsale de l'animal, en deux rangées parallèles à l'avant des ganglions cérébroïdes. On en dénombre 6 à 8 localisés dans le parenchyme céphalique. Ils consistent en une cupule pigmentaire entourant une cinquantaine de cellules visuelles qui rejoignent les centres nerveux supérieurs. Pour les cellules photoréceptrices on distingue:un processus dendritique riche en mitochondries, neurotubules, vacuoles et possédant un axe médian;un corps cellulaire où l'on trouve du réticulum endoplasmique rugueux, un appareil de Golgi développé mais peu de mitochondries.相似文献
6.
Alluchon-Gerard Marie Josèphe Gontcharoff Marie 《Development genes and evolution》1970,164(3):226-235
Sommaire ChezLineus ruber on observe deux types de développement dans la même ponte: un développement normal et un développement abortif. Les ufs qui donnent des embryons normaux émettent deux globules polaires, les ufs qui donnent des embryons anormaux n'émettent qu'un globule polaire. Ils ne sont pas fécondés mais commencent à se diviser et arrivent tardivement au stade 16–32 blastomères, puis la segmentation s'arrête. On suggère l'existence d'une parthénogénèse abortive. Les facteurs du déclenchement du processus du développement abortif sont discutés.
Abnormal development of some embryos of lineus ruber (O. F. Müller) (Heteronemertine)
Summary One can observe in the case ofLineus ruber, two types of development in the same egg string, a normal one and an abortive one. The eggs which give the normal embryos, give two polar bodies while the eggs which give the abnormal embryos, issue one polar body only, they are not fertilized but start to divide and belatedly reach the stade of 16–32 blastomeres.The existence of an abortive parthehogenesis is suggested and the mechanism of abnormal development is discussed.相似文献
7.
8.
9.
10.
B. Czeczuga 《Hydrobiologia》1981,78(1):45-48
The occurrence and contents of carotenoids in different body parts were investigated by column chromatography and TLC in Micropterus salmoides (Lalép).The following carotenoids were found: -carotene, -cryptoxanthin, -cryptoxanthin, echinenone, canthaxanthin, lutein, zeaxanthin, neothxanthin, tunaxanthin, -doradexanthin, -doradexanthin, idoxanthin, astaxanthin, astaxanthin ester, mutatochrome and mutatoxanthin.Their total contents varied within the range of 0.071–1.691 µg/g wet weight. 相似文献
11.
12.
Résumé On a étudié le metabolisme des Porphyrines de la Némerte marine Lineus ruber à l'aide d'acide delta aminolévulinique 4 C14 ou 2–3 H3. Chez les animaux traités, le marqueur est retrouvé au niveau des uroporphyrines séparées par chromatographie sur papier. Ce résultat nous a permis l'étude autoradiographique de la mise en place des Uroporphyrines dans les cellules pigmentaires en régénération. Ce type de travail permet de suivre la différenciation biochimique des cellules pigmentaires avant que ne soit commencée leur différenciation morphologique.
Summary The metabolism of porphyrins was studied in the marine Nemertean worm Lineus ruber with delta aminolevulinic acid 4 C14 or 2–3 H3. All the radioactivity was found in the uroporphyrins isolated by paper chromatography. This result permits us to do the autoradiographic study of the appearance of uroporphyrins in regenerating pigment cells. Such a work allows to see the biochemical differentiation of pigment cells before the starting of their morphological differentiation.相似文献
13.
14.
15.
16.
17.
《Comptes Rendus Palevol》2002,1(1):67-74
The settlement of Chalcolithic metalworkers of La Capitelle du Broum is a truly outstanding site. The first AMS 14C dating (3rd millennium BC) reveals it as the oldest site in the mining and metallurgy district of Cabrières. It is of the same age as the oldest metallurgy site discovered in continental France (Roquemengarde). It includes, near the prehistoric copper mines already discovered, double-facing dry-stone walls of the Fontbouisse type and a variety of metallurgy structures. Metalworking tools, including one of the very rare ingot crucibles known from this period in Western Europe, are found alongside ceramics typical of the Late Neolithic (Broum type?). To cite this article: P. Ambert et al., C. R. Palevol 1 (2002) 67–74. 相似文献
18.
19.
Yaacov Lensky 《Insectes Sociaux》1964,11(4):293-299
Summary The following is a study of resistance of worker honey bees (Apis mellifica L. var.ligustica) to high temperatures and of the effect of nutrition upon it.Survival of honey bees of spring generation was studied at 45, 50, 55 and 60°C during 15, 30, 45 and 60 minutes exposures. The survival rate was established at the end of their exposure, and 24 hours later. Lethal effects of heat were evident immediately after a 30 minute exposure to 50° C. These effects could be noticed in the survivers 24 hours following exposure.Effect of nutrition on heat resistance at 32° C and at 50° C was studied on one group of bees supplied with a 30 % honey solution; on another- with water only, and on a third group which served as a control (no food). Their survival at 32° C after 12 hours exposure was 100%, 81% and 48%, respectively. However, an exposure duration of 45 minutes at 50°C resulted in a survival of 22% of control bees as compared to a total survival of those fed on honey solution. 相似文献
20.