STUDIES ON THE LIFE CYCLE AND TAXONOMY OF LIGNIERA VERRUCOSA

Miller , Charles E. (A. and M. College of Texas, College Station.) Studies on the life cycle and taxonomy of Ligniera verrucosa. Amer. Jour. Bot. 46(10): 725–729. Illus. 1959.—A study of the roots of Veronica persica Poir. and V. hederaefolia L. plants infected with Sorosphaera veronicae Schroeter revealed intracellular cystosori and zoosporangial sori of Ligniera verrucosa. The zoosporangial phase of this species has been heretofore unknown. The plasmodia of L. verrucosa occur in root hairs, and other epidermal and sub-epidermal cells of the roots. Zoosporangial and cystosoral plasmodia are indistinguishable until cleavage has started. It is thought that plasmodia produced during early infection develop into zoosporangia, while those produced later develop into resting spores. Zoospores discharged from zoosporangia may reinfect host cells developing there into zoosporangial or cystosoral plasmodia. No evidence for any sexual process was observed. The spherical zoosporangia making up a single zoosporangial sorus may be interconnected; a single discharge pore may serve to liberate zoospores from different zoosporangia. In the Plasmodiophorales the classical basis for generic distinction has been the arrangement of the resting spores in the sorus. Ligniera, because of the supposedly uncharacteristic nature of its cystosori, has been suggested as a host-variety of Sorosphaera. A comparative study of the cystosori and zoosporangia of Ligniera and Sorosphaera growing in a single host has led to the conclusion that these genera should be considered distinct.     

A study of the hatching process in aquatic invertebrates. XVI. Events of eclosion in Calopsectra neoflavellus Malloch (Diptera,Tendipedidae). XVII. Hatching in Argulus megalops Smith (Crustacea,Branchiura)

Summary Hatching in the tendipedid, Calopsectra neoflavellus involves first a slow uptake of water by the embryo during development, whereby it increases in size and comes to fill entirely the space within the chorion. After completion of embryonic development, the prolarva increases still more in size by swallowing and absorbing water. Internal pressure thus generated results in the bursting of the chorion. The larva then frees itself by active movements.In the branchiuran, Argulus megalops, hatching is similar to that previously described for Copepoda, in that an inner egg membrane swells osmotically and splits the outer chorion. Subsequent bursting of the inner membrane throws the larva nearly out of the egg, but final emergence is by active struggle of the larva.

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Zusammenfassung Das Ausschlüpfen von Calopsectra neoflavellus enthält erstens eine langsame Wasseraufnahme durch den Embryo, wodurch der Embryo wächst und das Wasser den ganzen Raum zwischen Embryo und Chorion füllt. Nach Vollendung der Entwicklung quillt der Embryo noch mehr auf durch den Schluckakt und Aufnahme des Wassers. Dann zerreisst das Chorion durch den intraovularen Druck. Endlich befreit sich die Larve durch Sträuben.In Argulus megalops (Branchiura) gleicht das Ausschlüpfen dem vorher dargestellten für den Copepoden. Eine innere Membran schwillt osmotisch und zerreisst; das Chorion dann zerreist auch die innere Membran selbst and wirft die Larve nahezu aus dem Ei hinaus, aber die schliessiiche Befreiung geschieht durch Sträuben.

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Supported by National Science Foundation grant GB-219, entitled A study of hatching and of the ecology of egg masses of aquatic invertebrates.     

Serological studies of types A, B, and E botulinal toxins by passive hemagglutination and bentonite flocculation

Johnson, H. M. (Robert A. Taft Sanitary Engineering Center, Cincinnati, Ohio), K. Brenner, R. Angelotti, and H. E. Hall. Serological studies of types A, B, and E botulinal toxins by passive hemagglutination and bentonite flocculation. J. Bacteriol. 91:967-974. 1966.-Formalinized sheep red blood cells (SRBC), sensitized with types A, B, and E botulinal toxoids and toxins by bis-diazotized benzidine (BDB), were tested against A, B, and E antitoxins prepared in horses and rabbits. Type B antitoxin cross-reacted with A toxoid SRBC, but the reciprocal cross-reaction was not observed. E toxin SRBC were specifically agglutinated by E antitoxin. Flocculation of antigen-sensitized bentonite particles was less sensitive in titration of antitoxin than hemagglutination. Also, reciprocal cross-reactions were observed between types A and B antitoxins. Cross-reactions in both serological tests were eliminated by titration of antitoxins in the presence of the heterologous antigens, with no inhibitory effect on the homologous antitoxins. Generally, equine antitoxins were less suitable for agglutinations, especially of antigen-sensitized bentonite particles. Types A, B, and E antitoxins were specifically inhibited by 43, 39, and 245 mouse ld(50) of their respective homologous toxins in the hemagglutination-inhibition test. A, B, and E antitoxins were specifically inhibited by 500, 950, and 1,500 mouse ld(50) of their respective homologous toxins in bentonite flocculation inhibitions. Formalinized SRBC sensitized with rabbit types A and B antitoxins by BDB were respectively clumped by as little as 0.75 to 1.3 mouse ld(50) of A toxin and 2.3 ld(50) of B toxin, whereas bentonite particles sensitized by the same antitoxins were specifically clumped by 150 ld(50) of A toxin and 630 ld(50) of B toxin. E antitoxin sensitization of SRBC or bentonite particles was not successful. Evidence is presented that indicates that the serological procedures are applicable to the detection of botulinal toxins in food.