Studies on Planktonic Bacteria by Means of a Direct Membrane Filter Method
- 1 June 1958
- journal article
- research article
- Published by Microbiology Society in Journal of General Microbiology
- Vol. 18 (3) , 609-620
- https://doi.org/10.1099/00221287-18-3-609
Abstract
Direct observations on the occurrence and spatial distribution of planktonic bacteria were made by using a membrane filter technique. The membrane filters were treated to allow direct microscopic examination of bacteria on their surfaces. Deviations between direct counts on the membranes and plate (colony) counts of bacteria depended upon availability of organic matter in the natural waters studied, and can be accounted for by clumping effects and the occurrence of very small forms not visible on the membrane filter surfaces. Indirect evidence for these "dwarf" forms was provided by later development of colonies with cells of normal size, after the membrane filter was placed on a nutrient medium. This response suggests that the organisms are zymogenous forms. Pure cultures of Bacillus subtilis and Pseudomonas fluorescens were used in some experiments to demonstrate the relationship between the clumping effect and concentration of dissolved nutrients in water. A concentration of 0.5 mg peptone/1 in a tap-water medium caused accumulations of bacteria around clean chitin particles; accumulations of bacteria did not develop at the higher concentrations tested. This behavior is explained by the local differences in concentrations of nutrients in the medium. It correlates with the observations on natural populations.Keywords
This publication has 8 references indexed in Scilit:
- Botanical limnological methods with special reference to the algaeThe Botanical Review, 1957
- TECHNIQUE FOR MICROSCOPIC COUNT OF MICROORGANISMS DIRECTLY ON MEMBRANE FILTERSJournal of Bacteriology, 1955
- Studies on Nonfruiting MyxobacteriaJournal of Bacteriology, 1947
- The Effect of Solid Surfaces upon Bacterial ActivityJournal of Bacteriology, 1943
- Bacteriology of fresh water: III. The types of bacteria present in lakes and streams and their relationship to the bacterial flora of soilEpidemiology and Infection, 1942
- Relation between Food Concentration and Surface for Bacterial GrowthJournal of Bacteriology, 1940
- OBSERVATIONS ON THE MULTIPLICATION OF BACTERIA IN DIFFERENT VOLUMES OF STORED SEA WATER AND THE INFLUENCE OF OXYGEN TENSION AND SOLID SURFACESThe Biological Bulletin, 1936
- Studies of Freshwater BacteriaJournal of Bacteriology, 1933