Morphologic variation and the rate of growth of bacteria, by Arthur T. Henrici ...

Abstract

reserve material and protected by a more or less resistant membrane. Gonidia and regenerative bodies participate actively in the process of multiplication, whereas the other reproductive organs are in the first place resting forms. Gonidia, regenerative bodies, and probably microcysts are produced by all bacteria, while arthrospores, exo-and endospores are less common; though there are indications that they will be discovered in many more cases, as soon as these problems are more thoroughly investigated (1921, p. 162). All bacteria live, in vivo as well as in vitro, alternately in an organized and in an amorphous stage. By the partial or complete dissolution of the vegetative and reproductive cells, a plasmatic mass, the symplasm, is formed, which, after a period of rest, according to circumstances may transform itself into new cells of the same or of a more or less modified character The formation of the bacterial symplasm proceeds always in two phases: First, the cells agglomerate to smaller or larger clumps; second, a more or less complete dissolution of the cells takes place, resulting in a crumbly or slimy mass The reconstruction of new cells from the bacterial symplasm follows various lines according to the internal as well as the external conditions (quality of the symplasm, environment, and technique). At first always regenerative units become visible, which either grow up separately to new cells, or of which several may agglomerate and surround themselves with a uniting membrane, thus forming at once full-grown cells. (1921, p. 195). He also describes another process as conjunction, where two or more cells combine without previous disintegration. Lohnis is careful to point out that "by discussing the life cycles of bacteria we do not intend to revive any of those unclear theories concerning bacterial polymorphism or pleomorphism. The development of bacteria is characterized not by the irregular occurrence of more or less abnormal forms but by the regular occurrence of many different forms and stages of growth connected with each other by constant relations" (1916, p. 677). But the diagram which he presents to show these constant relations, with its numerous arrows connecting each type with many others, and with double points indicating their reversibility, leaves one without any clear notion of regularity, but rather with the idea, in vogue in Naegeli's day, that any bacterial type may develop in a haphazard way from any other. Indeed, from neither text nor illustrations can one gain any exact impression of the sequence of events in the life cycle he postulates. Mellon, in a long series of papers extending over ten years, has described morphologic variations in diphtheroid bacteria, typhoid and colon bacilli, and fusiform organisms; many of his papers deal with 35, 36, 37, 38 Minot, C. S

Oceanicaulis alexandrii gen. nov., sp. nov., a novel stalked bacterium isolated from a culture of the dinoflagellate Alexandrium tamarense (Lebour) Balech

“…The five strains are proposed to comprise a new species of a new genus, Oceanicaulis alexandrii gen. nov., sp. nov., the type strain of which is C116-18 T (=DSM 11625Since the original description of the genus Caulobacter by Henrici & Johnson (1935), stalked bacteria from a wide range of sources, including soils, freshwater and marine environments, have been assigned to the genus, mainly on the basis of their characteristic prosthecate (Anast & Smit, 1988;Stahl et al, 1992). Originally thought to be restricted exclusively to oligotrophic habitats, in the last decade an extensive number of isolates exhibiting heterotrophic traits and relatively versatile metabolisms have been isolated from eutrophic environments, such as secondary waste water treatment facilities (Fenton, 1994;MacRae & Smit, 1991), and assigned to the genus Caulobacter.…”

Aerobic microbial transformation of pesticides in surface water

“…The biological interactions are also important, as indicated by the fact that the blooming pulse of cyanobacteria and diatoms are followed by the increase of bacterial counts, likely due to the supply of organic matters from planktons. 68) Both the temperature dependence and biological interactions in the production and abundance of bacterioplanktons have been confirmed through 8-year monitoring in a hypertrophic lake. 69) By analyzing several bacterial profiles for 80 bacteria isolated from three ponds, Hashizume et al 43) reported marked horizontal variation in the distribution of these bacteria with their seasonal changes.…”

The physics of biofilms—an introduction

“…His report in 1676 marks the discovery of biofilms [9]. However, only in the first half of the twentieth century with the work of Henrici [10] and Zobel [11] was the import of biofilms really appreciated by the scientific community, and finally the word biofilm was first used in 1981 [12], which marks the recognition of its function and organization.…”