Primitive or Filterable Forms of Bacteria

Sherman, James M.; Safford, Clair E.

doi:10.1126/science.74.1928.602

Cited by 7 publications

(4 citation statements)

References 9 publications

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“…The notion of bacteria that pass through membrane filters with microsize pores drew considerable attention in the 1930s (2)(3)(4)(5). All these reports referred to "filterable bacteria" as those that can pass through filters with 0.45 µm and larger pores.…”

Section: Introductionmentioning

confidence: 99%

“…Microfiltration (0.1−0.45 μm pore size) is commonly used for sterilization of heat-sensitive pharmaceutical and labora tory solutions and also for the physical removal of microbial cells during the treatment of drinking water and wastewater (). The notion of bacteria that pass through membrane filters with microsize pores drew considerable attention in the 1930s ( − ). All these reports referred to “filterable bacteria” as those that can pass through filters with 0.45 μm and larger pores.…”

Section: Introductionmentioning

confidence: 99%

“…All these reports referred to "filterable bacteria" as those that can pass through filters with 0.45 µm and larger pores. Some researchers regarded filterable bacteria as a new group of organisms (5), whereas others suggested filterable forms as a biological stage in the bacterial life cycle (2,6). Most of this work was done based on filtration experiments with suspended cultures of pathogenic bacteria (6).…”

Section: Introductionmentioning

confidence: 99%

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Quantification of the Filterability of Freshwater Bacteria through 0.45, 0.22, and 0.1 μm Pore Size Filters and Shape-Dependent Enrichment of Filterable Bacterial Communities

Wang

Hammes

Boon

et al. 2007

Environ. Sci. Technol.

137

109

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Micro-filtration is a standard process for sterilization in scientific research, medical, and industrial applications, and to remove particles in drinking water or wastewater treatment. It is generally assumed, and confirmed by quantifying filtration efficiency by plating, that filters with a 0.1-0.45 microm pore size can retain bacteria. In contrast to this assumption, we have regularly observed the passage of a significant fraction of natural freshwater bacterial communities through 0.45, 0.22, and 0.1 microm pore size filters. Flow cytometry and a regrowth assay were applied in the present study to quantify and cultivate filterable bacteria. Here we show for the first time a systematic quantification of their filterability, especially their ability to pass through 0.1 microm pore size filters. The filtered bacteria were subsequently able to grow on natural assimilable organic carbon (AOC) with specific growth rates up to 0.47 h(-1). We were able to enrich bacteria communities that pass preferentially through all three pore size filters at significantly increased percentages using successive filtration-regrowth cycles. In all instances, the dominant microbial populations comprised slender spirillum-shaped Hylemonella gracilis strains, suggesting shape-dependent selection during the filtration process. This quantification of the omnipresence of microfilterable bacterial in natural freshwater and their regrowth characteristics demand a change in the sterile filtration practice used in industrial and engineering applications as well as scientific research.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quantification of the Filterability of Freshwater Bacteria through 0.45, 0.22, and 0.1 μm Pore Size Filters and Shape-Dependent Enrichment of Filterable Bacterial Communities

Wang

Hammes

Boon

et al. 2007

Environ. Sci. Technol.

137

109

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“…The recent experimental work of , Sherman (1931), andHadley, Delves andKlimek (1931) indicates that filterability may be a much more common characteristic of bacteria under certain conditions of cultivation than had hitherto been believed. But that all or even many species of bacteria are at times both filterable and characterized by a cyclogenic mode of development seems to be an assumption unwarranted by known facts.…”

Section: Filterabilitymentioning

confidence: 99%