Toxic indole alkaloids avrainvillamide and stephacidin B produced by a biocide tolerant indoor mold Aspergillus westerdijkiae.

Toxic Aspergillus westerdijkiae were present in house dust and indoor air fall-out from a residence and a kindergarten where the occupants suffered from building related ill health. The A. westerdijkiae isolates produced indole alkaloids avrainvillamide (445 Da) and its dimer stephacidin B (890 Da).

Potato crop as a source of emetic Bacillus cereus and cereulide-induced mammalian cell toxicity.

Bacillus cereus, aseptically isolated from potato tubers, were screened for cereulide production and for toxicity on human and other mammalian cells. The cereulide-producing isolates grew slowly, the colonies remained small (~1 mm), tested negative for starch hydrolysis, and varied in productivity from 1 to 100 ng of cereulide mg (wet weight)(-1) (~0.01 to 1 ng per 10(5) CFU).

20-Residue and 11-residue peptaibols from the fungus Trichoderma longibrachiatum are synergistic in forming Na+/K+ -permeable channels and adverse action towards mammalian cells.

Certain species of the filamentous fungal genus Trichoderma (e.g. Trichoderma longibrachiatum and Trichoderma citrinoviride) are among the emerging clinical pathogens and also the most common species in the indoor space of mould-damaged buildings.

The Fusarium mycotoxins enniatins and beauvericin cause mitochondrial dysfunction by affecting the mitochondrial volume regulation, oxidative phosphorylation and ion homeostasis.

The mechanisms of cell toxicity of mycotoxins of the enniatin family produced by Fusarium sp. enniatin B, a mixture of enniatin homologues (3% A, 20% A(1), 19% B, 54% B1) and beauvericin, were investigated. In isolated rat liver mitochondria, exposure to submicromolar concentrations of the enniatin mycotoxins depleted the mitochondrial transmembrane potential, uncoupled oxidative phosphorylation, induced mitochondrial swelling and decreased calcium retention capacity of the mitochondria.

Microbial toxin's effect on mitochondrial survival by increasing K+ uptake.

We studied the effects of toxins, which inhibited the motility of boar spermatozoa, on rat liver mitochondria. The toxins studied were originally from bacteria isolated from moisture-damaged buildings where inhabitants exhibited symptoms, or from food causing poisoning. Some strains of Bacillus cereus and Streptomyces griseus produced potassium ionophoric peptides cereulide and valinomycin (Mikkola, et al.

Novel mycotoxin from Acremonium exuviarum is a powerful inhibitor of the mitochondrial respiratory chain complex III.

A novel mycotoxin named acrebol, consisting of two closely similar peptaibols (1726 and 1740 Da), was isolated from an indoor strain of the mitosporic ascomycete fungus Acremonium exuviarum. This paper describes the unique mitochondrial toxicity of acrebol, not earlier described for any peptaibol. Acrebol inhibited complex III of the respiratory chain of isolated rat liver mitochondria (1 mg of protein mL(-1)) with an IC(50) of approximately 80 ng mL(-1) (50 nM) after a short preincubation, and 350 ng mL(-1) caused immediate and complete inhibition.

In vitro toxicity of cereulide on porcine pancreatic Langerhans islets.

Cereulide is a K(+) ionophore cytotoxic and mitochondriotoxic to primary cells and cell lines of human and other mammalian origins. It is a heat-stable, highly lipophilic (logK(ow) 5.96) peptide (1152 g mol(-1)) produced by certain strains of Bacillus cereus, a bacterium connected to emetic food poisonings.

Architecture of Deinococcus geothermalis biofilms on glass and steel: a lectin study.

Deinococcus geothermalis is resistant to chemical and physical stressors and forms tenuous biofilms in paper industry. The architecture of its biofilms growing on glass and on stainless acid proof steel was studied with confocal laser scanning microscopy and fluorescent lectins and nanobeads as in situ probes. Hydrophobic nanobeads adhered to the biofilms but did not penetrate to biofilm interior.

Bafilomycin A1 is a potassium ionophore that impairs mitochondrial functions.

Novel activities of bafilomycin A1, a macrolide antibiotic known as an inhibitor of V-ATPases, were discovered. Bafilomycin A1 induced uptake of potassium ions by energized mitochondria and caused mitochondrial swelling, loss of membrane potential, uncoupling of oxidative phosphorylation, inhibition of the maximal respiration rates, and induced pyridine nucleotide oxidation. The mitochondrial effects provoked by nanomolar concentrations of bafilomycin A1 were connected to its activity as a potent, K(+)-specific ionophore.

Amylosin from Bacillus amyloliquefaciens, a K+ and Na+ channel-forming toxic peptide containing a polyene structure.

Bacillus amyloliquefaciens strains isolated from the indoor environment of moisture-damaged buildings produce a 1197 Da toxin, named amylosin. Nuclear magnetic resonance (NMR) data showed that amylosin contains a chromophoric polyene structure and the amino acids leucine/isoleucine, proline, aspartic acid/asparagine, glutamic acid/glutamine and tyrosine. A quantitation method for amylosin was developed using commercially available amphotericin B as a reference compound and a known concentration of amylosin determined by NMR with the electronic reference to access in vivo concentration (ERETIC) method.

Isolation and automated ribotyping of Mycobacterium lentiflavum from drinking water distribution system and clinical specimens.

Automated ribotyping as a tool for identifying of nontuberculous mycobacteria was evaluated. We created a database comprising of riboprints of 60 strains, representing 32 species of nontuberculous mycobacteria. It was shown that combined ribopatterns generated after digestion with EcoRI and PvuII were distinguishable between species of both slow-growing and rapid-growing mycobacteria.

Potential of selected infant food formulas for production of Bacillus cereus emetic toxin, cereulide.

Cereulide producing Bacillus cereus was isolated from randomly chosen commercial infant foods. The cereulide production in infant food formulas was investigated. When the reconstituted foods were inoculated with >10(5) cfu ml(-1) of cereulide producing B.

Intranasal exposure to Stachybotrys chartarum enhances airway inflammation in allergic mice.

Rationale: Exposure to building dampness, often associated with growth of microbes such as Stachybotrys chartarum, has been linked to respiratory symptoms. We have shown previously in a murine model that exposure to S. chartarum can induce lung inflammation characterized by infiltration of neutrophils and lymphocytes; this process is regulated by proinflammatory cytokines and leucocyte-attracting chemokines.

Cereulide-producing strains of Bacillus cereus show diversity.

Producers of cereulide, the emetic toxin of Bacillus cereus, are known to constitute a specific subset within this species. We investigated physiological and genetic properties of 24 strains of B. cereus including two high cereulide producers (600-1,800 ng cereulide mg(-1) wet weight biomass), seven average producers (180-600 ng cereulide mg(-1) wet weight biomass), four low cereulide producers (20-160 ng cereulide mg(-1) wet weight biomass) and 11 non-producers representing isolates from food, food poisoning, human gut and environment.

The higher toxicity of cereulide relative to valinomycin is due to its higher affinity for potassium at physiological plasma concentration.

Valinomycin and cereulide are bacterial toxins with closely similar chemical structure and properties but different toxic effects. Emetic poisoning is induced by cereulide but not by valinomycin. Both are specific potassium ionophores.

Valinomycin-induced apoptosis of human NK cells is predominantly caspase independent.

Human NK cells are sensitive to the exogenous toxic compound valinomycin. This toxin, produced by Streptomyces griseus in moisture damaged buildings, induces apoptosis by dissipating the membrane potential in mitochondria. In this paper, we show that valinomycin-induced apoptosis involves two different pathways in human NK cells: the predominant one is caspase-3 independent and the other caspase-3 dependent.

Mitochondrial toxicity detected in a health product with a boar spermatozoan bioassay.

Seaweed and organic alfalfa capsules sold as "health promoting" products had repeatedly caused emesis in a consumer. Using the boar spermatozoan bioassay, the capsule contents were found to contain a toxic substance that inhibited boar sperm motility and depolarised mitochondria at low exposure concentrations of 10 microg/ml. The capsule also contained high amounts (10(5)-10(7) cfu/g), of endospore-forming bacteria and Streptomyces-like bacteria.

Lipopolysaccharides of anaerobic beer spoilage bacteria of the genus Pectinatus--lipopolysaccharides of a Gram-positive genus.

Bacteria of the genus Pectinatus emerged during the seventies as contaminants and spoilage organisms in packaged beer. This genus comprises two species, Pectinatus cerevisiiphilus and Pectinatus frisingensis; both are strict anaerobes. On the basis of genomic properties the genus is placed among low GC Gram-positive bacteria (phylum Firmicutes, class Clostridia, order Clostridiales, family Acidaminococcaceae).

Methylobacillus pratensis sp. nov., a novel non-pigmented, aerobic, obligately methylotrophic bacterium isolated from meadow grass.

Strain F31T was isolated from meadow grass (Poa trivialis L.) sampled from the city park in Helsinki. Analysis of phenotypic and genotypic properties showed the strain to be related to the group of obligately methylotrophic non-methane utilizing bacteria (methylobacteria) with the ribulose monophosphate pathway of formaldehyde assimilation.

Biological effects of Trichoderma harzianum peptaibols on mammalian cells.

Trichoderma species isolated from water-damaged buildings were screened for toxicity by using boar sperm cells as indicator cells. The crude methanolic cell extract from Trichoderma harzianum strain ES39 inhibited the boar sperm cell motility at a low exposure concentration (50% effective concentration, 1 to 5 microg [dry weight] ml of extended boar semen(-1)). The same exposure concentration depleted the boar sperm cells of NADH(2).

Sperm bioassay for rapid detection of cereulide-producing Bacillus cereus in food and related environments.

A novel in vitro method, sperm micro assay for rapidly distinguishing cereulide, the emetic toxin producing Bacillus cereus from non-producers is described and its use for quantitating cereulide and screening large numbers of B. cereus strains/colonies evaluated. The assay is non-laborious and can be executed with equipment present in most laboratories.

Bacillus amyloliquefaciens strains isolated from moisture-damaged buildings produced surfactin and a substance toxic to mammalian cells.

Fungicidic Bacillus amyloliquefaciens strains isolated from the indoor environment of moisture-damaged buildings contained heat-stable, methanol-soluble substances that inhibited motility of boar spermatozoa within 15 min of exposure and killed feline lung cells in high dilution in 1 day. Boar sperm cells lost motility, cellular ATP, and NADH upon contact to the bacterial extract (0.2 microg dry wt/ml).

Potential of Bacillus cereus for producing an emetic toxin, cereulide, in bakery products: quantitative analysis by chemical and biological methods.

A method for the direct quantitative analysis of cereulide, the emetic toxin of Bacillus cereus, in bakery products was developed. The analysis was based on robotized extraction followed by quantitation of cereulide by liquid chromatography-mass spectrometry and an assay of toxicity by the boar sperm motility inhibition test. The bioassay and the chemical assay gave comparable results, demonstrating that the extracted cereulide was in a biologically active form.

Chelatobacter heintzii (Auling et al. 1993) is a later subjective synonym of Aminobacter aminovorans (Urakami et al. 1992).

Chelatobacter heintzii, which was described as a nitrilotriacetate-utilizing organism, was re-investigated in order to clarify its taxonomic position. On the basis of 16S rDNA sequence comparisons, it is obvious that this species clusters phylogenetically with species of the genus Aminobacter. The results of investigations of the fatty acid patterns, polar lipid profiles, polyamine patterns and quinone system supported this placement.

Methylobacterium suomiense sp. nov. and Methylobacterium lusitanum sp. nov., aerobic, pink-pigmented, facultatively methylotrophic bacteria.

Two aerobic, pink-pigmented, facultatively methylotrophic bacteria, strains F20T and RXM(T), are described taxonomically. On the basis of their phenotypic and genotypic properties, the isolates are proposed as novel species of the genus Methylobacterium, Methylobacterium suomiense sp. nov.