A contribution to the functional morphology of the midgut gland in phalangiid harvestmen Gyas annulatus and Gyas titanus during their life cycle.

The structure of the midgut gland and its changes in different seasons have been examined in the harvestmen Gyas annulatus and Gyas titanus (Arachnida: Opiliones: Phalangiidae). In both species, in the epithelium of the midgut gland two different types of cells are present: secretory and digestive ones. The secretory cells are characterized by plentiful rER and secretory granula. The digestive cells are characterized by an apical system of tubules. Both cells are connected by prominent specialized junctions. If a secretory cell is in contact with a digestive cell, rER cisterna are in close vicinity and parallel to these junctions. As found light- and electron microscopically and also histochemically, glycogen and lipids are stored in both cells. In both species, glycogen was seen to be used as energy compound during overwintering. At the end of their life, the digestive cells develop into excretory ones, containing metabolic wastes.

New method for isolation of venom from the sea anemone Actinia cari. Purification and characterization of cytolytic toxins.

1. Venom from the sea anemone Actinia cari was obtained by the "milking" method. Two lethal and hemolytic polypeptide toxins, caritoxins I (CTX I) and II (CTX II), were isolated with gel and ion exchange chromatography. 2. The mol. wt of the pure toxin was 19,800. The isoelectric points of CTX I and II were 9.45 and 10.0, respectively. The toxins had similar amino acid compositions lacking cysteine. 3. The intravenous CTX I and CTX II lethal dose (LD50) in mice was found to be 54 +/- 25 and 90 +/- 1 micrograms/kg, respectively. Their hemolytic activity was inhibited by sphingomyelin.

Isolation and partial characterization of three lethal and hemolytic toxins from the sea anemone Actinia cari.

Three lethal and hemolytic toxins, caritoxin I, II and III were isolated from the sea anemone Actinia cari. Following controlled autolysis, tentacles were strained through a nylon sieve and thus a crude extract was obtained. The toxins were further purified by Sephadex G-75 gel chromatography. All three toxins which were eluted at the same peak, were separated by ion-exchange chromatography on CM-cellulose. Disc-PAGE revealed electrophoretic homogeneity of caritoxin II. Caritoxin I was obtained in pure form following rechromatography on CM-cellulose. Purified toxins were stable in the pH range 3 - 8. The preliminary determined molecular weight of the toxins was 20 - 25000 daltons. All three toxins are basic proteins. Isoelectric point of caritoxin I was determined as 10.7. The isolated toxins are lethal (LD 5o of caritoxin I is 22 microgram/kg mice, i.v.) and indicate high hemolytic activity with a pH optimum between 8 and 9. Sphingomyelin specifically and irreversibly inhibits the hemolytic activity of caritoxins as well as some other sea anemone cytolytic toxins.