Are Aquatic Phycomycetes Present in the Air?

Abstract

IN the course of a study of the seasonal variation of micro-organisms in the air of Montreal, in connexion with departmental studies on airborne fungi¹, nutrient agar plates were exposed at regular intervals by the G—E Duplex electrostatic bacterial air sampler² on the roof of the Biological Building of McGill University. The number of micro-organisms per cubic foot air was readily calculated from the countings of colonies versus times of exposure, the sampler having a uniform flow of 1 cu. ft. per ruin. The length of the sample was ten minutes. Among many common species of bacteria, actinomycetes, yeasts and moulds, an interesting aquatic phycomycete later identified as Hyphochytrium catenoides Karling was encountered. This organism was found on an agar plate 223 exposed on the positive electrode of the sampler in the morning of April 29, 1949, on the roof of the Biological Building of McGill University. The weather that morning was clear, with the air temperature 48–50° F. and light winds. In the past week, it had been mainly overcast or cloudy, with occasional light rains and showers. There were altogether eighty-two colonies on the plate, including seventy-two bacteria, one actinomycete, one yeast and seven other fungi. The colony of this fungus was well isolated, slightly raised, pale yellow, slimy, yeast-like, and had attained a diameter of 5 mm. The medium used in this investigation was Czapek's solution agar modified by substitution of 5 gm. glucose instead of sucrose and the addition of 1 gm. yeast extract per litre. All plates were incubated at 24° C. for 10–14 days before examination.