MicrobiologyOpen

Ubiquitation is an active and dynamic process in Giardia. Different types of ubiquitin modifications are present in this ancestral unicellular eukaryote and vary in terms of temporal and spatial distribution from trophozoites to cyst maturation. Using a proteomics approach, we identified around 200 high-confidence ubiquitinated candidates that vary their ubiquitination status during differentiation.

Transcriptomic analysis of a gacA mutant identified 771 genes including many novel genes in Pseudomonas chlororaphis 30-84. The rsmZ and rsmE genes were linked to phenazine production. Our results also showed that constitutive expression of the quorum sensing transcriptional activator phzR, with the addition of N-acyl-homoserine lactones did not rescue phenazine production in the gacA mutant, indicating the direct posttranscriptional control by Gac of the phenazine biosynthetic genes. Figure shows proposed model of Gac/Rsm regulation of phenazines in 30-84

Phylogenetic analysis suggested that Erythrobacter, Rhodovulum, Stappia and Thalassospira of Alphaproteobacteria were the prevailing groups in the sea surface oil mousse collected during the Deepwater Horizon oil spill, and this pattern may relate to high temperatures and strong irradiance in surface Gulf waters. In the salt marshes mousse, Vibrio represented 57% of the total operational taxonomic units, suggesting that this indigenous genus is particularly responsive to the oil contamination in salt marshes. In contrast, bacterial community in oil-contaminated sediments near the well head was much diversified.

Both conventional plating and denaturing gradient gel electrophoresis (DGGE) were used to analyse the effect of fungicides on epiphytic yeasts associated with strawberry. The results show that the main epiphytic yeasts are not affected by the fungicides and this could lead to an integrated use of epiphytic yeasts to control fungal diseases of strawberry.

The genes encoding HilA and HilB from Pantoea ananatis AJ13355 were cloned and expressed in Escherichia coli. The culturing of E. coli cells expressing hilA (E. coli-HilA) or both hilA and hilB (E. coli-HilAB) in the presence of l-isoleucine resulted in the conversion of l-isoleucine into two novel biogenic compounds: l-4′-isoleucine and l-4,4′-dihydroxyisoleucine, respectively. In parallel, two novel enzymatic activities were detected in the crude cell lysates of the E. coli-HilA and E. coli-HilAB strains: l-isoleucine-4′-dioxygenase (HilA) and l-4′-hydroxyisoleucine-4-dioxygenase (HilB) activities, respectively.

Schematic diagram of summarizing the induction of alginate production and mucoid conversion by PilA in Pseudomonas aeruginosa strain PAO579. The sigma factor RpoN is required for transcription of pilA108 and algW. PilA108 is transported to the periplasm where it activates the periplasmic protease AlgW which proteolytically degrades the anti-sigma factor MucA releasing the sequestered sigma factor AlgU.

The understanding of CYN synthesis would be crucial in control CYN production. Amidinotransferase (AMDT) seems to be the first enzyme involved in CYN synthesis. We have cloned and overexpressed the aoaA gene, which codifies for the AMDT, the constitutive CYN producer Aphanizomenon ovalisporum UAM-MAO. Purified AoaA was characterized, confirming that it is an l-arginine:glycine AMDT.

Ability of the photosynthetic bacterium Rubrivivax gelatinosus to form biofilm. The EmbRS two-component system inhibits biofilm formation. Growth of the EmbRS mutant results in the formation of conspicuous bacterial veils around the toothpick scaffolds.

We performed a comprehensive analysis of bacterial and eukaryotic communities of river biofilms by pyrosequencing rDNA amplicons. The data indicated a large diversity among prokaryotes with a predominance of Proteobacteria, together with an elevated number of rare sequences. Altogether, this would indicate an important photosynthetic activity within the biofilm.

Here, we report that overexpression of a [PSI⁺]-inducible Q/N-rich protein, Lsm4, eliminates the three major prions [PSI⁺], [URE3], and [RNQ⁺]. In the course of the Lsm4-driven [PSI⁺] elimination, the [PSI⁺] aggregates undergo a size increase, which ultimately results in the formation of conspicuous foci in otherwise [psi⁻]-like mother cells. We also found that the antiprion activity is a general property of [PSI⁺]-inducible factors. These data provoked a novel “unified” model that explains both prion induction and elimination by a single scheme.

We found a novel Porphyromonas gingivalis pigment-less mutant by transposon mutagenesis: the gene responsible was the PGN_2005 gene of strain ATCC 33277. Based on the analysis of the LPS pattern of the PGN_2005 mutant, the location and structure of the PGN_2005 protein and complementation of an Escherichia coli wzz mutant by the PGN_2005 gene, we believe that the PGN_2005 protein is Wzz of P. gingivalis, designated WzzP. In addition, in this study, we determined that the PGN_1896 and PGN_1233 proteins and the PGN_1033 protein appear to be WbaP homolog proteins and a Wzx homolog protein, respectively.

Functional amyloids in Pseudomonas (Fap) are so far only described for a single environmental isolate, termed Pseudomonas fluorescens UK4. Here, we show that medical and technical important Pseudomonas strains, including P. aeruginosa PAO1, have the genetical capacity to produce Fap. Expression of Fap triggers cell autoaggregation and speed up biofilm formation.