Wilhelm Roux Archiv Fur Entwicklungsmechanik Der Organismen最新文献

The decrease of the phosphorylated state of the adenine nucleotide system (ATP)/(ADP) (HPO ₄^-2 ) during oocyte maturation of the loach (Misgurnus fossilis L.) correlated with the fall of the (NAD⁺)/(NADH) ratio. A increase of the cytoplasmic (NADP⁺)/(NADPH) ratio was also found.

1) The effect of juvenile hormone on embryonic development in the cricket,Acheta domesticus, was investigated. Application of 1 to 2.5 μg of methyl 12,14-dihomojuvenate (cecropia juvenile hormone) in 1 μl of acetone to 7-day-old cricket embryos inhibited their further growth. In such embryos, differentiation of some of the embryonic organs and tissues such as nerves, muscles and cuticular structures continued. However, embryonic growth was arrested, their morphology was abnormal and they failed to hatch. 2) Lipid extracts from adult maleHyalophora cecropia which possess juvenile hormone activity also showed similar effects on embryonic development. But lipid extracts prepared from allatectomized adult maleH. cecropia lacking juvenile hormone activity, did not inhibit embryonic development. 3) DNA synthesis in the embryonic tissues of the JH-treated and control embryos was investigated using an autoradiographic method of determination of H³ thymidine incorporation into nuclear DNA. The results showed that DNA synthesis in epidermal and mesenchymal cells of the cricket embryo decreased gradually after application of 1 μg of JH to 7-day-old embryos and ceased within 6 days after application of JH. 4) From these observations it is suggested that JH may inhibit embryonic development by suppression of DNA synthesis and cell divisions.

The whole specific activities of 5 lysosomal enzymes (acid phosphatase, N-acetylβ-glucosaminidase,β-glucuronidase, cathepsin and aryl sulphatase) were measured in the guts of Discoglossus tadpoles, before and during metamorphosis.For each hydrolase, the activities show the same variation pattern. They significantly increase at the end of prometamorphosis and the beginning of the climax, while there is histolysis of the first (primary) epithelium of the gut.The measured activities decrease at the end of the climax, while a secondary, enzyme-negative epithelium is developing.The free specific activity of the acid phosphatase was measured in these same guts. It significantly increases at the end of prometamorphosis and the beginning of the climax, during the epithelial histolysis. The total activity increases more slowly than the free one.In the same way, an increase is obtained for the specific activity of the bound (intralysosomal) acid phosphatase.The changes in whole enzymatic activities may result from accelerated synthesis of lysosomal hydrolases due to the primary epitheliocytes, and induced by the simultaneous increase in the plasmatic level of the thyroid hormones. Furthermore the free activity of the acid phosphatase may produce an increased permeability or a breaking of the lysosomal membrane, by the same hormones.

Localization of 4 dephosphorylating enzymes (alkaline phosphomonoesterase, acid phosphomonoesterase, nonspecific ATP-ase, and AMP-ase=5' nucleotidase) has been studied in both constituants of the fore- and hind limb buds inPleurodeles waltlii Michah. during the first stages of development.There is no specific enzymatic reaction in the bud epiderm; the negative or positive results concerning the four enzyme groups are observed in the whole epiderm of the larval body and not only in the limb bud epiderm: the epiderm is devoid of the alkaline phosphomonoesterases which hydrolyze sodiumβ-glycerophosphate and sodiumα-naphthyl phosphate, and of AMP-ase and acid sodiumβ-glycerophosphatase; it is rich in ATP-ase and acid naphthol AS/BI phosphatase). The enzymatic reactions studied are present in the limb bud mesoderm, with the exception of the acidβ-glycerophosphatasic one. At the level of the basement membrane, only in the fore and hind limb buds, the reaction for alkalineβ-glycerophosphatase is positive.

Ooplasmic segregation inPhallusia mammillata was completed 3 to 5 min after fertilization. Colchicine, which completely stopped nuclear divisions, did not inhibit segregation. Cytochalasin B, which prevented cleavage at a low concentration (0.2 μg/ml) inhibited segregation only at a concentration at least five times higher. The action of these drugs leads to the conclusion that ooplasmic segregation does not depend on an assembly of microtubules or on microfilaments which are involved in cell division.

Histological studies do not permit the distinction between an oocyte, ovary or oviduct malformation as the primary cause of sterility in females homozygous for the Hairywing 49c allele inDrosophila melanogaster. Reciprocal transplantations of larval ovaries between homozygous mutant larvae and normal larvae demonstrate that the sterility is due to a malfunctioning of the oviduct, presumably at the junction of the common oviduct and the uterus. This failure of the oviduct to function normally appears to represent a unique cause of female sterility in this organism.

It is only during the first days after hatching that similarities are found in the titer variations of haemolymph proteins in imagines of all castes of the honeybee. Later on caste-specific features occur.The ontogenesis of titer variations of all protein fractions is described for queens, workers, and drones. In the case of adult queens and egg-laying workers as well vitellogenin is predominant. In normal workers vitellogenic material is only present during the nurse phase. Generally the haemolymph protein pattern of worker bees shows the largest titer changes.Defined periods in the development of haemolymph protein patterns coincide with known age-dependent successions of behavioral activities. Their social regulation is discussed.

Xenoplastic recombinates of animal ectodermal caps with the ventral vegetative yolk mass of blastulae of stage 81/2-83/4 ofA. mexicanum, T. alpestris, T. cristatus carnifex andP. waltlii have demonstrated unambiguously that in the urodeles the primordial germ cells-together with other ventro-caudal mesodermal structures-develop from the animal ectodermal moiety of the blastula under an inductive influence emanating from the ventral vegetative yolk mass. Similar recombinates of³H-labeled and unlabeled ectodermal and endodermal components fully support this conclusion.Recombinates of the ventral vegetative yolk mass with different regions of the animal ectodermal hemisphere show that primordial germ cells can be formed by any region of the animal ectodermal hemisphere, including those regions which in normal development will never form them. The number of primordial germ cells formed differs significantly among the various regions, that of the ventral peripheral region being the highest and that of the central, animal region the lowest. The capacity for primordial germ cell formation shows two increasing gradients, one animal-vegetative and the other dorse-ventral (in the peripheral zone). Although accurate measurements could not be made, there seems to be a relation between the number of primordial germ cells formed and the amount of ventro-caudal mesoderm induced.The experiments, moreover, show that notochord differentiation largely or entirely suppresses primordial germ cell formation. Notochord differentiation shows a similar animalvegetative, but an opposite ventro-dorsal increase in frequency (in the peripheral zone) as compared with the capacity for primordial germ cell formation. The notochord-forming gradient in the peripheral regions is mainly due to the inductive action already exerted by the dorsal vegetative yolk mass in the intact blastula prior to isolation and recombination (see control explants). The ventro-dorsal decline in primordial germ cell formation in the peripheral regions is very probably due only to the inhibition of primordial germ cell formation by notochord differentiation (as an expression of dorsal mesoderm induction). Therefore, in the animal ectodermal moiety of the blastula there exists only an animal-vegetative gradient in mesodermal competence.These results make it very likely that in urodeles the primordial germ cells do not arise from predetermined elements such as those demonstrated in anurans, but develop from common, totipotent animal ectodermal cells. The discrepancy in the mode of origin of the primordial germ cells between anurans and urodeles could be due only to pronounced differences in the time of appearance of the germinal cytoplasm (in anurans during oogenesis, in urodeles possibly during determination of the primordial germ cells within the ventro-caudal mesoderm).The differences in site and mode of origin of the primordial germ cells between urodeles and anurans favor a dual phyl

Sterility in the Hairy-wing 49c mutant ofDrosophila melanogaster is due to the failure of mature oocytes to pass from the oviduct into the uterus.Patterns of oocyte accumulation in the ovaries, oviducts and uterus of mutant and wild-type flies indicate that ovulation is initiated first by mating and thereafter by the absence of an oocyte in the uterus. While oocyte production is also stimulated by mating, it is maintained by a low number of oocytes in the ovary.Mating also appears to initiate events which cause mature oocytes to deteriorate if they are not soon oviposited.

Ripe eggs of the Ichneumonid waspPimpla turionellae are activated by the deformation of the egg during oviposition or experimental treatment. The structure of eggs prior to oviposition differs from that of eggs after natural or imitated oviposition. Histologieal sections of preoviposition eggs show a conspicuous cytoplasmic reticulum, which is torn up in eggs after oviposition. The structure of total, living eggs which are treated mechanically, some of which subsequently develop, varies considerably. It is not possible to predict the developmental fate of an egg by its structural features. The observation of a variability in structure, also among normally developing eggs, supports our assumption that the function of the alteration of egg architecture lies in the triggering of processes rather than in the specific arrangement of an organization pattern. It is argued that at least 2 dynamic systems, one causing completion of meiosis and the other ooplasmic flows, must be activated in the egg by oviposition. We postulate, furthermore, that in the Hymenoptera egg, activation by deformation of the egg at oviposition is a common phenomenon.