A Simple Method for Producing Microcultures in Hanging Drops with special reference to Organisms Utilizing Oils

Abstract

SUMMARY: An aseptic technique is described for obtaining small hanging drops on the surface of coverslips, using only apparatus that is cheap and easy to obtain. The technique has been used to demonstrate the growth of Nocardia salmonicolor on liquid paraffin droplets.Of all the methods used for studying the growth and development of microorganisms in liquid culture in undisturbed condition the hanging drop is probably the best. The ordinary hanging-drop method, as used for routine examination of gross bacterial morphology and motility, yields unavoidably large drops and is unsuited to the study of the growth and development of a few cells. Microbiologists requiring more stringent control of drop size have turned to the technique of micromanipulation, but for the average worker the apparatus required is too time-consuming and tedious to construct. The technique described below is offered for those workers who do not require the refinements of micromanipulation methods. The apparatus required is cheap and easy to obtain. METHODThe method consists of spraying a suspension of organisms, in the medium in which they are to be studied, on to the surface of coverslips. The suspension is made of such a density that the droplets formed on the coverslip surface contain a few cells each. The coverslip is then inverted over a well slide containing liquid paraffin and incubated at the required temperature.

Psychrobacillus glaciei sp. nov., a psychrotolerant species isolated from an Antarctic iceberg

“…2). Gliding motility and endospore forming ability were assessed by the hanging-drop method [21] and the endospore-staining method [22].…”

Lysobacter lacus sp. nov., isolated from from lake sediment

“…Cell morphology was examined with the scanning electron microscope (SU-3500, Hitachi), using cells grown for 2 days at 30 °C on R2A agar. Cell motility was determined using the hanging drop method [20]. Catalase and oxidase tests were performed as described previously [21].…”

Isolation of thermotolerant and high acetic acid-producing Acetobacter pasteurianus from Ivorian palm wine

“…Gram staining was performed and cells motility was observed by hanging drop method (Webley, 1953). Catalase test was performed with hydrogen peroxide and oxidase test with oxidase disks.…”