0000000000347320
AUTHOR
Reinhard Rachel
Proteinaceous Surface Layers ofArchaea: Ultrastructure and Biochemistry
The cell walls of the Archaea are composed of different polymers such as glutaminylglycan, heterosaccharide, methanochondroitin, pseudomurein, protein, glycoprotein, or glycocalyx. The S-layer glycoprotein of Halobacterium salinarum was the first glycoprotein discovered in bacteria and archaea. Initially, the novel cell wall structures were viewed as curiosities, and their taxonomic significance was not realized until the concept of the Archaea was published. At this time, the results of cell wall studies supported the new view of the phylogeny of the Bacteria and Archaea. Many archaea possess proteinaceous surface layers (S layers), which form two-dimensional regular arrays. The chemical s…
Regulation of type 1 fimbriae synthesis and biofilm formation by the transcriptional regulator LrhA of Escherichia coli
Type 1 fimbriae ofEscherichia colifacilitate attachment to the host mucosa and promote biofilm formation on abiotic surfaces. The transcriptional regulator LrhA, which is known as a repressor of flagellar, motility and chemotaxis genes, regulates biofilm formation and expression of type 1 fimbriae. Whole-genome expression profiling revealed that inactivation oflrhAresults in an increased expression of structural components of type 1 fimbriae.In vitro, LrhA bound to the promoter regions of the twofimrecombinases (FimB and FimE) that catalyse the inversion of thefimApromoter, and to the invertible element itself. TranslationallacZfusions with these genes and quantification offimEtranscript le…
Treponema isoptericolens sp. nov., a novel spirochaete from the hindgut of the termite Incisitermes tabogae.
A novel spirochaete, Treponema sp. strain SPIT5T, was isolated from hindgut contents of the drywood termite Incisitermes tabogae (Snyder). The cells of strain SPIT5T were motile, helical in shape, 0.4-0.5 microm in diameter and generally 12-20 microm long. The strain is obligately anaerobic and ferments different mono-, di- and oligosaccharides by forming ethanol as the main liquid fermentation end product. Furthermore, strain SPIT5T was able to grow anaerobically with yeast extract as sole carbon and energy source. Fastest growth was obtained at 30 degrees C, the temperature at which the termites were also grown. The optimum pH for growth was 7.2, with a range of pH 6.5-8.0. The cells poss…
Isolation of methanotrophic bacteria from termite gut.
The guts of termites feature suitable conditions for methane oxidizing bacteria (MOB) with their permanent production of CH4 and constant supply of O2 via tracheae. In this study, we have isolated MOB from the gut contents of the termites Incisitermes marginipennis, Mastotermes darwiniensis, and Neotermes castaneus for the first time. The existence of MOB was indicated by detecting pmoA, the gene for the particulate methane monooxygenase, in the DNA of gut contents. Fluorescence in situ hybridization and quantitative real-time polymerase chain reaction supported those findings. The MOB cell titer was determined to be 10(2)-10(3) per gut. Analyses of the 16S rDNA from isolates indicated clos…