Life cycle analysis of the model organism Rhodopirellula baltica SH 1^T by transcriptome studies

Abstract

SummaryThe marine organism Rhodopirellula baltica is a representative of the globally distributed phylum Planctomycetes whose members exhibit an intriguing lifestyle and cell morphology. The analysis of R. baltica's genome has revealed many biotechnologically promising features including a set of unique sulfatases and C1‐metabolism genes. Salt resistance and the potential for adhesion in the adult phase of the cell cycle were observed during cultivation. To promote the understanding of this model organism and to specify the functions of potentially useful genes, gene expression throughout a growth curve was monitored using a whole genome microarray approach. Transcriptional profiling suggests that a large number of hypothetical proteins are active within the cell cycle and in the formation of the different cell morphologies. Numerous genes with potential biotechnological applications were found to be differentially regulated, revealing further characteristics of their functions and regulation mechanisms. More specifically, the experiments shed light on the expression patterns of genes belonging to the organism's general stress response, those involved in the reorganization of its genome and those effecting morphological changes. These transcriptomic results contribute to a better understanding of thus far unknown molecular elements of cell biology. Further, they pave the way for the biotechnological exploitation of R. baltica's distinctive metabolic features as a step towards sourcing the phylum Planctomycetes at large.

Bioinformatic analyses of integral membrane transport proteins encoded within the genome of the planctomycetes species, Rhodopirellula baltica

“…Perhaps some of the protein secretion systems identified in this report will prove to reflect protein translocation between compartments as well as to the extracellular environment. Alternatively, is there reason to believe that these systems will serve the same functions during the different lifecycle stages of this organism [6]? These open questions indicate that R. baltica provides fertile waters for further investigation.…”

“…Rhodopirellula baltica is an aerobic marine halotolerant Planctomycete, a member of a diverse genus of ecological importance with an unusual cell structure, including an intracellular membrane-enclosed nucleoid, the pirellulosome [1-6]. It and other Planctomycetes exhibit resistance to a number of traditionally used antibiotics and heavy metals, and they have the capacity to degrade and utilize a wide range of organic materials in their environments [7-9].…”

“…R. baltica is a model Planctomycete with biotechnologically promising features [6, 28]. It forms complex mixed biofilm communities with biodegradative and bioremediative capabilities [29], degrades sulfated polymeric carbohydrates produced by kelp [26] and can oxidize anthropogenic and algae-produced haloalkanes [30, 31].…”

Beyond the bacterium: planctomycetes challenge our concepts of microbial structure and function

“…These sulphatases could be useful as industrial catalysts 99,100 . Transcriptomic studies indicated that these sulphatases may also be involved in the formation of disulphide bridges in cell wall proteins 101 .…”

Cell surface proteome of the marine planctomycete Rhodopirellula baltica

“…In native habitats, adult R. baltica cells attach firmly onto snow particles by a unique hold stalk structure []. Furthermore, transcriptomic analysis of the life cycle of R. baltica indicated that the cell wall is modified when the physiological state of the cells changes []. Genes involved in reorganization of the cell envelope were found to be regulated during life cycle.…”