Autoradiography after tritiated thymidine labeling of the abortive gametogenesis in hybrid male ducks from the cross male Pekin X female Barbary]

This autoradiographic data concludes that meiotic prophase of the abortive gametogenesis of the sterile hybride drake (from the mating Peking male = Anas platyrhynchos L. X Barbary female = Cairina moschata L.) lasts 5 days 1/4. 6 days after the injection of the marker the seminiferous tubules contain numerous labeles necrosing cells but never typical elongated spermatids.     

Mean and variance of the number of renewals of a censored Poisson process

Summary Expressions are derived for computing the mean and variance of the number of renewals in observation times of any length and for any values of the scaling parameter of the censored Poisson process. These results depend on certain identities involving the complex roots of unity. Computations show the oscillatory behavior to be expected when the average interval between renewals of the censored Poisson process is of the order of the observation time. Both ordinary and equilibrium renewal processes are considered.     

Furosemide induced release of prostaglandin E to increase renal blood flow.

Levels of PGE in renal venous blood were found to be significantly elevated at the time RBF was increased by furosemide. Following indomethacin, a second dose of furosemide failed to increase RBF and levels of PGE in renal venous blood were not elevated. Levels of PGF and PGA were not affected by furosemide. The increase of PGE in renal venous blood at the time of renal dilation supports the hypothesis that furosemide increases RBF by releasing PGE. An intrarenal action of the released PGE is implied by this mechanism.     

Method of isolating FMRF-amide-like substances in the snail, using affinity chromatography coupled with HPLC

An extraction procedure of FMRFa-like substances from brain of Helix aspersa was developed. It consists of using affinity chromatography coupled with reverse phase HPLC. Three synthetic peptides (FMRFa, pQDPFLRFa, Met-enkephalin) were used to evaluate the specificity and yield of the affinity column. Its efficiency was tested by use of snail brain extracts. The results showed that this method is efficient and reproducible.     

Red algae found on European salt-marshes. II. Catenella caespitosa (Rhabdoniaceae)

A survey is given of the taxonomy, life history and geography of Catenella caespitosa (With.) L. Irv. basedon study of living specimens, culture experiments, study of herbarium material and literature. This species is conspecific with Catenella repens (Lightf.) Batt. and Catenella opuntia (Good. & Woodw.) Grev. and several other taxa. Fragmentation is the most common mode of propagation of C. caespitosa. However, reproduction by tetraspores and by carpospores is also observed. The species is found in the tropics as well a in temperate climates.