Ulteriori osservazioni su Blastocystis della rana e conferma della natura e posizione sistematica dell'Alga

Summary

From our second contribution to the study of Blastocystis on the frog, the following conclusions are deduced:

• 1) on frogs mantained in captivity, the infestion of Blastocystis is easily generalized to all the individuals. This Protists is, apparently, diffused from one to another individual, and demonstrated by the alteration of normal content of the Amphibian rectal ampulla. However, the presence of Blastocystis on the life substrata of the frogs has non been demonstrated.

• 2) the negative results formerly obteined (1936) as to the pure culture of Blastocystis were confirmed, in spite of the tentative use of stains (against bacterial contaminations), micromanipulation, of filtering trough candle (according Newiadomski), and so on. The main difficulty on the study if Blastocystis life cycle and biological activities is related to the impure cultures up to now obtained.

• 3) The observations of Schilling and Santoni on the reproductive modalities of Blastocystis were fully confirmed, both “in vitro” and “in vivo”, particularly in regard to the direct fission and the sporulation. The last phenomen, in our opinion, is clearly an “endosporulations”, as the so called “ectosporulation” is without signification. On the contrary, the reproduction by budding (according Reyer) has not been observed. Apparently, this bud formation is one of the aspects of degraded or imperfect endosporulation, as observed on Blastocystis from man and mice in opposition to the better life cycle developed on Blastocystis from cold-blood animals.

• 4) The opposition of Schilling and Santoni against our view on Blastocystis as related to achloric Algae instead of Fungi (or Protozoa) is insustainable. As appearing from the actual results, a) the “internal body” of the Protist (homologous to the chromatophore of achloric Chlorophyceae); b) compsition of mucilaginous capsula; c) development of chondriome; d) variability in number and size of endospores; e) amytothic nuclear reproduction of cystoids (as in lower Algae); f) similarity with achloric Algae previously found in human intestine; g) reproduction by fission together the reproduction by endosporulation (as in the Protococcaceae); h) the tendency of fissing cells to heap up in small lumps on visions media, are favouring our hypothese.