Cytasters induced within unfertilized sea-urchin eggs.
نویسندگان
چکیده
Conditions that induce the formation of asters in unfertilized sea-urchin eggs have been investigated. Monasters were formed by treatment of eggs with acidic or basic sea-water, or procaine- or thymol-containing sea-water. A second treatment step, incubation with D2O-containing, ethanol-containing or hypertonic sea-water induced multiple cytasters. The number and size of cytasters varied according to the concentration of agents and duration of the first and second treatments, and also upon the species of eggs and the season in which the eggs were obtained. Generally, a longer second treatment or a higher concentration of the second medium resulted in a higher number of cytasters per egg. Asters were isolated and then examined by light and electron microscopy. Isolated monasters apparently lacked centrioles, whereas cytasters obtained from eggs undergoing the two-step treatment contained one or more centrioles. Up to eight centrioles were seen in a single aster; the centrioles appeared to have been produced during the second incubation. Centrospheres prepared from isolated asters retained the capacity to nucleate the formation of microtubules in vitro as assayed by light and electron microscopy. Many microtubules radiated from the centre of isolated asters, whether they contained centrioles or not. This observation is consistent with many other reports that microtubule-organizing centres need not contain centrioles.
منابع مشابه
Cytasters from sea urchin eggs parthenogenetically activated by procaine
A method is presented for the isolation of cytasters from unfertilized sea urchin eggs parthenogenetically activated by procaine. These cytasters do not appear to contain centrioles. The microtubules seem to grow out from the condensed chromosomes. The chromosomes have an unusual morphology.
متن کاملTubulin polymerization in unfertilized sea-urchin eggs induced by elevated temperature.
Spontaneous polymerization of tubulin was induced in unfertilized eggs of the sea urchins Lytechinus pictus and Strongylocentrotus purpuratus by warming to temperatures 10-12 deg. C above the normal environment for each species. Indirect immunofluorescence microscopy showed that over a period of several hours polymerization proceeded from a fine crystal-like precipitate to larger and fewer high...
متن کاملTaxol inhibits the nuclear movements during fertilization and induces asters in unfertilized sea urchin eggs
Taxol blocks the migrations of the sperm and egg nuclei in fertilized eggs and induces asters in unfertilized eggs of the sea urchins Lytechinus variegatus and Arbacia punctulata. Video recordings of eggs inseminated in 10 microM taxol demonstrate that sperm incorporation and sperm tail motility are unaffected, that the sperm aster formed is unusually pronounced, and that the migration of the e...
متن کامل"On the Nature of the Process of Fertilization and the Artificial Production of Normal Larvae (Plutei) From the Unfertilized Eggs of the Sea Urchin" (1899), by Jacques Loeb
Jacques Loeb [4] developed procedures to make embryos from unfertilized sea urchin [5] eggs in 1899. Loeb called the procedures ?artificial parthenogenesis," and he introduced them and his results in ?On the Nature of the Process of Fertilization and the Artificial Production of Norma Larvae (Plutei) from the Unfertilized Eggs of the Sea Urchin? in an 1899 issue of The American Journal of Physi...
متن کاملActin in triton-treated cortical preparations of unfertilized and fertilized sea urchin eggs
Triton-treated cortical fragments of unfertilized and fertilized sea urchin eggs prepared in the presence of greater than or equal to 5 mM EGTA contain 15-30% of the total egg actin. However, actin filaments are not readily apparent by electron microscopy on the cortical fragments of unfertilized eggs but are numerous on those of fertilized eggs. The majority of the actin associated with cortic...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of cell science
دوره 61 شماره
صفحات -
تاریخ انتشار 1983