Accumulating data suggest that the eukaryotic cell originated from a merger of two prokaryotes, an archaeal host and a bacterial endosymbiont. However, since prokaryotes are unable to perform phagocytosis, the means by which the endosymbiont entered its host is an enigma. We suggest that a predatory or parasitic interaction between prokaryotes provides a reasonable explanation for this conundru...

Biologists have long thought that the internal workings of prokary­ otes—the smallest and simplest organisms, including bacteria—are well understood, and have accordingly consid­ ered eukaryotic organisms and their cells to be more fascinating objects for study. During the past decade, however, the focus of some research has begun to turn back to prokaryotes—particularly because genomic analyse...

Evolutionary selection for optimal genome preservation, replication, and expression should yield similar chromosome organizations in any type of cells. And yet, the chromosome organization is surprisingly different between eukaryotes and prokaryotes. The nuclear versus cytoplasmic accommodation of genetic material accounts for the distinct eukaryotic and prokaryotic modes of genome evolution, b...

Glycosylation is one of the most abundant protein posttranslational modifications. Protein glycosylation plays important roles not only in eukaryotes but also in prokaryotes. To further understand the roles of protein glycosylation in prokaryotes, we developed a lectin binding assay to screen glycoproteins on an Escherichia coli proteome microarray containing 4,256 affinity-purified E.coli prot...

The basis of gliding motility in prokaryotes including certain mycoplasmas and the ability of mycoplasmas to retain their characteristic cell shapes in the absence of a supporting cell wall is unexplained. This review examines the available studies describing proteins resembling contractile proteins and cytoskeletal proteins in prokaryotes. Proteins with a significant degree of amino acid seque...

Because maintenance of non-scalable cellular components--membranes and chromosomes--requires an increasing fraction of energy as cell size decreases, miniaturization comes at a considerable energetic cost for a phytoplanktonic cell. Consequently, if eukaryotes can use their superior energetic resources to acquire nutrients with more or even similar efficiency compared with prokaryotes, larger u...

Our knowledge of the extent and functional impact of lateral gene transfer (LGT) from prokaryotes to eukaryotes, outside of endosymbiosis, is still rather limited. Here we review the recent literature, focusing mainly on microbial parasites, indicating that LGT from diverse prokaryotes has played a significant role in the evolution of a number of lineages, and by extension throughout eukaryotic...

Phylogenetic studies show that horizontal gene transfer (HGT) is a significant contributor to genetic variability of prokaryotes, and was perhaps even more abundant during the early evolution. Hitherto, research of natural HGT has mainly focused on three mechanisms of DNA transfer: conjugation, natural competence, and viral transduction. This paper discusses the feasibility of a fourth such mec...

Elevated levels of genetic drift are hypothesized to be a dominant factor that influences genome size evolution across all life-forms. However, increased levels of drift appear to be correlated with genome expansion in eukaryotes but with genome contraction in bacteria, suggesting that these two groups of organisms experience vastly different mutational inputs and selective constraints. To dete...

Biocontrol agents (BCA) effectively suppress soil-borne disease symptoms using natural antagonistic prokaryotes or eukaryotes. The main issue associated with the application of BCA is that disease reduction effects are unstable under different field conditions. In order to identify potentially effective BCA among several fields, we compared prokaryotic and eukaryotic communities in soil with an...