On the Nature of Mixed Cultures of Chlorella Pyrenoidosa TX 71105 and Various Bacteria

Abstract

SUMMARYThe growth of several selected micro-organisms in rapidly dividing cultures of Chlorella pyrenoidosa T X 71105 was studied. Bacterial proliferation was a function of algal growth and bacterial growth occurred, at least in part, as a result of the excretion of organic substances into the culture medium by rapidly dividing algae. These substances capable of supporting bacterial oxidation and growth were varied in kind and were utilized selectively by the different bacteria. Only a small fraction of the soil and air bacteria grew in the algal cultures. The majority of soil and air bacteria survived in mixed culture for several days but did not increase in numbers. On the other hand, 6 out of 8 bacteria pathogenic for man died promptly in cultures of Chlorella pyrenoidosa ; but Salmonella typhi and S . puratyphi grew well for extended periods of time. Fungi capable of producing macrocolonies on potato glucose agar at pH 3.5 did not increase in numbers during 8 days. Yeasts and actinomycetes were not detected by the methods used; bacteriophages were observed with some regularity .

Untersuchungen über die Beziehungen zwischen Algenblüten und Bakterienpopulationen in der Schlei (westliche Ostsee)

“…(1960), SIEBURTH & PRATT (1962), SI~BUr, TH (1968) and MOIKEHA & CHU (1971). Secretion of bactericide substances by freshwater green algae has been found by PRATT et al (1944), VELA &GUERRA (1966) andNIEWOLAK (1971a, b).…”

“…This is disputed, however, by GUNIft~L (1968). Experiments in vitro with various green algae (Chlorelta, Scenedesrnus) showed that the growth of certain bacteria is enhanced by these algae, whereas other bacteria strains are clearly inhibited (VELA & GUERRA, 1966;NIEWOLAi~, 1971a, b).…”

Analysis by Dansylation of Amino Acids Dissolved in Marine and Freshwaters1

“…During an investigation of compounds excreted during photoautotrophic growth of Chlore'lla sorokiniana, we had difficulties with excessive salt concentrations when the spent culture medium was concentrated sufficiently to permit standard amino acid (Vela and Guerra 1966).…”

“…To assess the effects of the components of seawater and of microbiological media on the dansylation reactions, we added 17 amino acids to 1 liter of modified Knop's medium (Vela and Guerra 1966) and to 2 liters of filtered, aged seawater; the final concentration of each amino acid was 1 X 10-Q M. After reaction and extraction, samples were chromatographed on TLC plates, and the Rb or R, values were calculated ( Table 1). The differences observed be- Pat&i (1966) pointed out that the more complex the solvent systems used and the mixtures to be separated, the mo,re variation there will be between the ideal and actual Rb values, because the components interact with each other and with the solvent systems.…”

“…The culture filtrate was a modified Knop's m.edium (Vela and Guerra 1966) in which Chlor& solrollciniana (Shihira and Krauss ) had been grown.…”