Biodegradation of saturate fraction of crude oil and production of signature carboxylic acids.

Bacteria degrading large portion of saturated hydrocarbons are important for crude oil bioremediation. This study investigates Novosphingobium sp. S1, Gordonia amicalis S2 and Gordonia terrae S5 capability of degrading wide range of saturated hydrocarbons from Congo Bilondo crude oil and discusses the degradation pathway.

Quorum sensing in biofilms: a key mechanism to target in ecotoxicological studies.

Our environment is heavily contaminated by anthropogenic compounds, and this issue constitutes a significant threat to all life forms, including biofilm-forming microorganisms. Cell-cell interactions shape microbial community structures and functions, and pollutants that affect intercellular communications impact biofilm functions and ecological roles. There is a growing interest in environmental science fields for evaluating how anthropogenic pollutants impact cell-cell interactions.

Features of the Opportunistic Behaviour of the Marine Bacterium in the Microalga Phycosphere.

Although interactions between microalgae and bacteria are observed in both natural environment and the laboratory, the modalities of coexistence of bacteria inside microalgae phycospheres in laboratory cultures are mostly unknown. Here, we focused on well-controlled cultures of the model green picoalga and the most abundant member of its phycosphere, . The prevalence of in cultures raises questions about how this bacterium maintains itself under laboratory conditions in the microalga culture.

AES and ToF-SIMS combination for single cell chemical imaging of gold nanoparticle-labeled .

A chemical fingerprint of the Escherichia coli cell surface labeled by gelatin coated gold nanoparticles was obtained by combining Auger Electron Spectroscopy (AES) for single cell level chemical images, and Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) Tandem MS for unambiguous molecular identification of co-localized species.

Description of Palleronia rufa sp. nov., a biofilm-forming and AHL-producing Rhodobacteraceae, reclassification of Hwanghaeicola aestuarii as Palleronia aestuarii comb. nov., Maribius pontilimi as Palleronia pontilimi comb. nov., Maribius salinus as Palleronia salina comb. nov., Maribius pelagius as Palleronia pelagia comb. nov. and emended description of the genus Palleronia.

Strain MOLA 401 was isolated from marine waters in the southwest lagoon of New Caledonia and was shown previously to produce an unusual diversity of quorum sensing signaling molecules. This strain was Gram-negative, formed non-motile cocci and colonies were caramel. Optimum growth conditions were 30°C, pH 8 and 3% NaCl (w/v).

Biofilm formation as a microbial strategy to assimilate particulate substrates.

In most ecosystems, a large part of the organic carbon is not solubilized in the water phase. Rather, it occurs as particles made of aggregated hydrophobic and/or polymeric natural or man-made organic compounds. These particulate substrates are degraded by extracellular digestion/solubilization implemented by heterotrophic bacteria that form biofilms on them.

Pleomorphochaeta naphthae sp. nov., a new anaerobic fermentative bacterium isolated from an oil field.

A novel anaerobic fermentative bacterium, strain SEBR 4209, was isolated from a water sample of a Congolese oil field. Strain SEBR 4209 is phylogenetically related to the genus Pleomorphochaeta, in the family Spirochaetaceae. Its closest relatives are Pleomorphochaeta caudata SEBR 4223 (94.

AupA and AupB Are Outer and Inner Membrane Proteins Involved in Alkane Uptake in Marinobacter hydrocarbonoclasticus SP17.

This study describes the functional characterization of two proteins, AupA and AupB, which are required for growth on alkanes in the marine hydrocarbonoclastic bacterium The and genes form an operon whose expression was increased upon adhesion to and biofilm formation on hexadecane. AupA and AupB are outer and inner membrane proteins, respectively, which are able to interact physically. Mutations in or/and reduced growth on solid paraffin and liquid hexadecane, while growth on nonalkane substrates was not affected.

Impact of temperature on SP17 morphology and biofilm structure during growth on alkanes.

Alkanes are widespread pollutants found in soil, freshwater and marine environments. () strain SP17 is a marine bacterium able to use many hydrophobic organic compounds, including alkanes, through the production of biofilms that allow their poor solubility to be overcome. This study pointed out that temperature is an environmental factor that strongly affects the biofilm formation and morphology of on the model alkanes, hexadecane and paraffin.

Pleomorphochaeta caudata gen. nov., sp. nov., an anaerobic bacterium isolated from an offshore oil well, reclassification of Sphaerochaeta multiformis MO-SPC2T as Pleomorphochaeta multiformis MO-SPC2T comb. nov. as the type strain of this novel genus and emended description of the genus Sphaerochaeta.

A strictly anaerobic Gram-stain-negative bacterium, designated strain SEBR 4223T, was isolated from the production water of an offshore Congolese oil field. Cells were non-motile, pleomorphic and had spherical, annular or budding shapes, often exhibiting long stalks. Strain SEBR 4223T grew on a range of carbohydrates, optimally at 37 °C and pH 7, in a medium containing 40 g l-1 NaCl.

The extracellular matrix of the oleolytic biofilms of Marinobacter hydrocarbonoclasticus comprises cytoplasmic proteins and T2SS effectors that promote growth on hydrocarbons and lipids.

The assimilation of the nearly water insoluble substrates hydrocarbons and lipids by bacteria entails specific adaptations such as the formation of oleolytic biofilms. The present article reports that the extracellular matrix of an oleolytic biofilm formed by Marinobacter hydrocarbonoclasticus at n-hexadecane-water interfaces is largely composed of proteins typically cytoplasmic such as translation factors and chaperones, and a lesser amount of proteins of unknown function that are predicted extra-cytoplasmic. Matrix proteins appear to form a structured film on hydrophobic interfaces and were found mandatory for the development of biofilms on lipids, alkanes and polystyrene.

Substrates specialization in lipid compounds and hydrocarbons of Marinobacter genus.

The impact of petroleum contamination and of burrowing macrofauna on abundances of Marinobacter and denitrifiers was tested in marine sediment mesocoms after 3 months incubation. Quantification of this genus by qPCR with a new primer set showed that the main factor favoring Marinobacter abundance was hydrocarbon amendment followed by macrofauna presence. In parallel, proportion of nosZ-harboring bacteria increased in the presence of marcrofauna.

The marine bacterium Marinobacter hydrocarbonoclasticus SP17 degrades a wide range of lipids and hydrocarbons through the formation of oleolytic biofilms with distinct gene expression profiles.

Hydrophobic organic compounds (mainly lipids and hydrocarbons) represent a significant part of the organic matter in marine waters, and their degradation has an important impact in the carbon fluxes within oceans. However, because they are nearly insoluble in the water phase, their degradation by microorganisms occurs at the interface with water and thus requires specific adaptations such as biofilm formation. We show that Marinobacter hydrocarbonoclasticus SP17 develops biofilms, referred to as oleolytic biofilms, on a large variety of hydrophobic substrates, including hydrocarbons, fatty alcohols, fatty acids, triglycerides, and wax esters.

Genome sequence of the marine bacterium Marinobacter hydrocarbonoclasticus SP17, which forms biofilms on hydrophobic organic compounds.

Marinobacter hydrocarbonoclasticus SP17 forms biofilms specifically at the interface between water and hydrophobic organic compounds (HOCs) that are used as carbon and energy sources. Biofilm formation at the HOC-water interface has been recognized as a strategy to overcome the low availability of these nearly water-insoluble substrates. Here, we present the genome sequence of SP17, which could provide further insights into the mechanisms of enhancement of HOCs assimilation through biofilm formation.

Physiological adaptation of Desulfitobacterium hafniense strain TCE1 to tetrachloroethene respiration.

Desulfitobacterium spp. are ubiquitous organisms with a broad metabolic versatility, and some isolates have the ability to use tetrachloroethene (PCE) as terminal electron acceptor. In order to identify proteins involved in this organohalide respiration process, a comparative proteomic analysis was performed.

Cells dispersed from Marinobacter hydrocarbonoclasticus SP17 biofilm exhibit a specific protein profile associated with a higher ability to reinitiate biofilm development at the hexadecane-water interface.

Biofilm formation by marine hydrocarbonoclastic bacteria is commonly observed and has been recognized as an important mechanism for the biodegradation of hydrocarbons. In order to colonize new oil-water interfaces, surface-attached communities of hydrocarbonoclastic bacteria must release cells into the environment. Here we explored the physiology of cells freshly dispersed from a biofilm of Marinobacter hydrocarbonoclasticus developing at the hexadecane-water interface, by combining proteomic and physiological approaches.

Behavior of Marinobacter hydrocarbonoclasticus SP17 cells during initiation of biofilm formation at the alkane-water interface.

Hexadecane assimilation by Marinobacter hydrocarbonoclasticus SP17 occurs through the formation of a biofilm at the alkane-water interface. In this study we focused on the interactions of cells with the alkane-water interface occurring during initiation of biofilm development. The behavior of cells at the interface was apprehended by investigating alterations of the mechanical properties of the interface during cell adsorption, using dynamic drop tensiometry measurements.

Proteomic analysis of Marinobacter hydrocarbonoclasticus SP17 biofilm formation at the alkane-water interface reveals novel proteins and cellular processes involved in hexadecane assimilation.

Many hydrocarbon-degrading bacteria form biofilms at the hydrocarbon-water interface to overcome the weak accessibility of these poorly water-soluble substrates. In order to gain insight into the cellular functions involved, we undertook a proteomic analysis of Marinobacter hydrocarbonoclasticus SP17 biofilm developing at the hexadecane-water interface. Biofilm formation on hexadecane led to a global change in cell physiology involving modulation of the expression of 576 out of 1144 detected proteins when compared with planktonic cells growing on acetate.

Cytoplasmic wax ester accumulation during biofilm-driven substrate assimilation at the alkane--water interface by Marinobacter hydrocarbonoclasticus SP17.

During growth on n-alkanes, the marine bacterium Marinobacter hydrocarbonoclasticus SP17 formed a biofilm at the alkane-water interface. We showed that hexadecane degradation was correlated with biofilm development and that alkane uptake is localized in the biofilm but not in the bulk medium. Biofilms were observed in cultures on metabolizable n-alkanes (C8-C28) and n-alcohols (C12 and C16), but were formed neither on non-metabolizable alkanes (pristane, heptamethylnonane and n-C32) nor on inert substrata (glass, polystyrene and Permanox).

Sensitive detection of selenoproteins in gel electrophoresis by high repetition rate femtosecond laser ablation-inductively coupled plasma mass spectrometry.

A laser ablation-ICPMS method using an infrared (1030 nm), low-energy (39 microJ/pulse), high repetition rate (10 kHz), femtosecond laser was developed to improve the sensitivity of detection of heteroatom-containing proteins in 1D polyacrylamide gels. A 2-mm-wide lane was ablated by ultrafast (10 cm s(-1)) back-and-forth movement of a 20-microm laser beam parallel to the protein bands while the gel advanced perpendicularly. This procedure resulted in a considerable increase in detection sensitivity (>40-fold) compared to the nanosecond 266-nm laser ablation-ICPMS, mainly because of the much larger amount of ablated material introduced into the plasma on the time scale of the dwell time of the mass spectrometer.

Methionine sulfoxide reductases protect Ffh from oxidative damages in Escherichia coli.

In proteins, methionine residues are primary targets for oxidation. Methionine oxidation is reversed by methionine sulfoxide reductases A and B, a class of highly conserved enzymes. Ffh protein, a component of the ubiquitous signal recognition particle, contains a methionine-rich domain, interacting with a small 4.

Repair of oxidized proteins. Identification of a new methionine sulfoxide reductase.

Oxidation of methionine residues to methionine sulfoxide can lead to inactivation of proteins. Methionine sulfoxide reductase (MsrA) has been known for a long time, and its repairing function well characterized. Here we identify a new methionine sulfoxide reductase, which we referred to as MsrB, the gene of which is present in genomes of eubacteria, archaebacteria, and eucaryotes.

Unfolding and internalization of proteins by the ATP-dependent proteases ClpXP and ClpAP.

ClpX and ClpA are molecular chaperones that interact with specific proteins and, together with ClpP, activate their ATP-dependent degradation. The chaperone activity is thought to convert proteins into an extended conformation that can access the sequestered active sites of ClpP. We now show that ClpX can catalyze unfolding of a green fluorescent protein fused to a ClpX recognition motif (GFP-SsrA).

Enzymatic and structural similarities between the Escherichia coli ATP-dependent proteases, ClpXP and ClpAP.

Escherichia coli ClpX, a member of the Clp family of ATPases, has ATP-dependent chaperone activity and is required for specific ATP-dependent proteolytic activities expressed by ClpP. Gel filtration and electron microscopy showed that ClpX subunits (Mr 46, 000) associate to form a six-membered ring (Mr approximately 280, 000) that is stabilized by binding of ATP or nonhydrolyzable analogs of ATP. ClpP, which is composed of two seven-membered rings stacked face-to-face, interacts with the nucleotide-stabilized hexamer of ClpX to form a complex that could be isolated by gel filtration.