Stress adaptation in a pathogenic fungus.

Candida albicans is a major fungal pathogen of humans. This yeast is carried by many individuals as a harmless commensal, but when immune defences are perturbed it causes mucosal infections (thrush). Additionally, when the immune system becomes severely compromised, C.

Fungal iron availability during deep seated candidiasis is defined by a complex interplay involving systemic and local events.

Nutritional immunity--the withholding of nutrients by the host--has long been recognised as an important factor that shapes bacterial-host interactions. However, the dynamics of nutrient availability within local host niches during fungal infection are poorly defined. We have combined laser ablation-inductively coupled plasma mass spectrometry (LA-ICP MS), MALDI imaging and immunohistochemistry with microtranscriptomics to examine iron homeostasis in the host and pathogen in the murine model of systemic candidiasis.

Differential adaptation of Candida albicans in vivo modulates immune recognition by dectin-1.

The β-glucan receptor Dectin-1 is a member of the C-type lectin family and functions as an innate pattern recognition receptor in antifungal immunity. In both mouse and man, Dectin-1 has been found to play an essential role in controlling infections with Candida albicans, a normally commensal fungus in man which can cause superficial mucocutaneous infections as well as life-threatening invasive diseases. Here, using in vivo models of infection, we show that the requirement for Dectin-1 in the control of systemic Candida albicans infections is fungal strain-specific; a phenotype that only becomes apparent during infection and cannot be recapitulated in vitro.

Extreme zinc tolerance in acidophilic microorganisms from the bacterial and archaeal domains.

Zinc can occur in extremely high concentrations in acidic, heavy metal polluted environments inhabited by acidophilic prokaryotes. Although these organisms are able to thrive in such severely contaminated ecosystems their resistance mechanisms have not been well studied. Bioinformatic analysis of a range of acidophilic bacterial and archaeal genomes identified homologues of several known zinc homeostasis systems.

Oxidative stress response in the opportunistic oral pathogen Fusobacterium nucleatum.

The anaerobic, Gram-negative bacillus Fusobacterium nucleatum plays a vital role in oral biofilm formation and the development of periodontal disease. The organism plays a central bridging role between early and late colonizers within dental plaque and plays a protective role against reactive oxygen species. Using a two-dimensional gel electrophoresis and mass spectrometry approach, we have annotated 78 proteins within the proteome of F.

Iron homeostasis and responses to iron limitation in extreme acidophiles from the Ferroplasma genus.

Extremely acidophilic archaea from the genus Ferroplasma inhabit iron-rich biomining environments and are important constituents of naturally occurring microbial consortia that catalyze the production of acid mine drainage. A combined bioinformatic, transcript profiling, and proteomic approach was used to elucidate iron homeostasis mechanisms in "F. acidarmanus" Fer1 and F.

Biofilm development in the extremely acidophilic archaeon 'Ferroplasma acidarmanus' Fer1.

'Ferroplasma acidarmanus' Fer1 is an iron-oxidizing extreme acidophile isolated from the Iron Mountain mine, California, USA. This archaeon is predominantly found in biofilm-associated structures in the environment, and produces two distinct biofilm morphologies. Bioinformatic analysis of the 'F.

Substrate-driven gene expression in Roseburia inulinivorans: importance of inducible enzymes in the utilization of inulin and starch.

Roseburia inulinivorans is a recently identified motile representative of the Firmicutes that contributes to butyrate formation from a variety of dietary polysaccharide substrates in the human large intestine. Microarray analysis was used here to investigate substrate-driven gene-expression changes in R. inulinivorans A2-194.

Kinetic characterization and quaternary structure of glutamate racemase from the periodontal anaerobe Fusobacterium nucleatum.

Cofactor-independent glutamate racemases (GRs) that supply the d-glutamate required for biosynthesis of the peptidoglycan that encapsulates bacterial cells are attractive targets for the development of antibacterial drugs. Recombinant GR from Fusobacterium nucleatum (FnGR), a Gram-negative anaerobe involved in periodontal disease, was overproduced, purified, and characterized. Unlike most other GRs, FnGR is a pseudosymmetric enzyme, catalyzing the racemization of glutamate enantiomers with similar kinetic parameters (k(cat)(L-->D)=17.

Proteomic investigation of amino acid catabolism in the indigenous gut anaerobe Fusobacterium varium.

The butyrate-producing anaerobe Fusobacterium varium is an integral constituent of human gut microflora. Unlike many gut microorganisms, F. varium is capable of fermenting both amino acids and glucose.

Proteomic investigation of glucose metabolism in the butyrate-producing gut anaerobe Fusobacterium varium.

A proteome survey and MS analysis were conducted to investigate glucose metabolism in Fusobacterium varium, a butyrate-producing constituent of the indigenous human gut microflora. The bacterium was capable of catabolizing glucose as the main energy source via the Embden-Meyerhof-Parnas pathway. 2-DE analyses revealed that the apparent concentrations of the six identified glycolytic enzymes (pyruvate kinase, enolase, glucose-6-phosphate isomerase, phosphoglycerate kinase, triosephosphate isomerase, and glyceraldehyde-3-phosphate dehydrogenase) were specifically increased in response to the presence of glucose in the chemically defined minimal growth medium, and did not diminish when the medium was additionally supplemented with L-glutamate, an amino acid readily fermented by members of the Fusobacterium genus.

The ypdI gene codes for a putative lipoprotein involved in the synthesis of colanic acid in Escherichia coli.

In Escherichia coli, the synthesis of colanic acid, an extracellular polysaccharide imminent in biofilm development, is a complicated process involving numerous genes and not yet wholly elucidated. Using a plasmid-borne E. coli K-12 gene library, we have identified a clone whose presence conferred mucoid colony phenotype onto E.

The acrAB locus is involved in modulating intracellular acetyl coenzyme A levels in a strain of Escherichia coli CM2555 expressing the chloramphenicol acetyltransferase (cat) gene.

Recently, an Escherichia coli CM2555 strain was described as sensitive to chloramphenicol when expressing the chloramphenicol resistance gene (cat) from a multicopy plasmid. This sensitivity was linked to dysfunction of the acrA gene, which encodes a component of the AcrAB-TolC multidrug efflux pump. Preliminary data indicate that the sensitivity phenotype might be due to a decline in intracellular acetyl coenzyme A concentration accompanying the reaction catalyzed by chloramphenicol acetyltransferase, the cat-encoded resistance protein.

The combined use of chemical and biochemical markers to assess water quality in two low-stream rivers (NE Spain).

Carps (Cyprinus carpio) and red swamp crayfish (Procambarus clarkii) were sampled from two lowstream Mediterranean rivers (Anoia and Cardener) receiving extensive urban and industrial waste water discharges. Tissue residues of selected pollutants (organochlorinated compounds, polycyclic aromatic hydrocarbons (PAHs)) were determined in conjunction with different biochemical responses (cytochrome P450, phase II enzymes) with the aim of investigating whether resident organisms were responsive to changes in water quality. Biota inhabiting those rivers were highly exposed to complex mixtures of polychlorobiphenyls and dichlorodiphenyltrichloroethanes (up to 19 ng/g w.

Inactivation of the acrA gene is partially responsible for chloramphenicol sensitivity of Escherichia coli CM2555 strain expressing the chloramphenicol acetyltransferase gene.

An Escherichia coli CM2555 strain, sensitive to chloramphenicol when expressing the cat gene and producing active chloramphenicol acetyltransferase (CAT), was described recently. It was proposed that this sensitivity is due to decreased levels of acetyl coenzyme A (Acetyl CoA) in cat-expressing CM2555 cells in the presence of chloramphenicol. CAT catalyzes transfer of the acetyl moiety from Acetyl CoA to a chloramphenicol molecule.

Assessment of organotin pollution along the Polish coast (Baltic Sea) by using mussels and fish as sentinel organisms.

Levels of tributyltin (TBT) and its degradation products, mono- (MBT) and dibutyltin (DBT), as well as triphenyltin (TPT), were monitored in 10 stations along the Polish coast (Baltic Sea). Mussel-Mytilus edulis-and fish-Platichthys flesus-were used as sentinel organisms. The bioaccumulation patterns of butyltin and phenyltin compounds varied substantially.