Natural marine bacteria as model organisms for the hazard-assessment of consumer products containing silver nanoparticles.

Scarce information is available regarding the fate and toxicology of engineered silver nanoparticles (AgNPs) in the marine environment, especially when compared to other environmental compartments. Hence, the antibacterial activity of the NM-300 AgNPs (OECD programme) and a household product containing colloidal AgNPs (Mesosilver) was investigated using marine bacteria, pure cultures and natural mixed populations (microcosm approach). Bacterial susceptibility to AgNPs was species-specific, with Gram negative bacteria being more resistant than the Gram positive species (NM-300 concentration used ranged between 0.

Novel brominated metabolites from Bryozoa: a functional analysis.

Marine invertebrates are a promising source of novel natural products with biological activities. The phylum Bryozoa is relatively under-investigated in this context, although a number of compounds with medical potential has been discovered in recent years. Here, we report on the novel group of brominated metabolites from the bryozoan Terminoflustra membranaceatruncata, including analysis of biological activities of the tribrominated terminoflustrindole A (Cm-1) and the structures of the related dibrominated variants terminoflustrindoles B and C.

Shifts in the metabolic function of a benthic estuarine microbial community following a single pulse exposure to silver nanoparticles.

The increasing use of silver nanoparticles (AgNPs) as a biocidal agent and their potential accumulation in sediments may threaten non-target natural environmental bacterial communities. In this study a microcosm approach was established to investigate the effects of well characterized OECD AgNPs (NM-300) on the function of the bacterial community inhabiting marine estuarine sediments (salinity 31‰). The results showed that a single pulse of NM-300 AgNPs (1 mg L(-1)) that led to sediment concentrations below 6 mg Ag kg(-1) dry weight inhibited the bacterial utilization of environmentally relevant carbon substrates.

Bryozoan metabolites: an ecological perspective.

This Highlight covers the chemical ecology of bryozoans, primarily the ecological functions of bryozoan natural products. The Highlight is arranged taxonomically, according to the bryozoan Treatise classification (P. Bock, Bryozoa Homepage, 2006, http://bryozoa.

Single-nucleotide polymorphism detection using nanomolar nucleotides and single-molecule fluorescence.

We have exploited three methods for discriminating single-nucleotide polymorphisms (SNPs) by detecting the incorporation or otherwise of labeled dideoxy nucleotides at the end of a primer chain using single-molecule fluorescence detection methods. Good discrimination of incorporated vs free nucleotide may be obtained in a homogeneous assay (without washing steps) via confocal fluorescence correlation spectroscopy or by polarization anisotropy obtained from confocal fluorescence intensity distribution analysis. Moreover, the ratio of the fluorescence intensities on each polarization channel may be used directly to discriminate the nucleotides incorporated.

Using flow cytometry to quantify microbial heterogeneity.

Flow cytometry is a powerful technique for the study of single cells, and thus it is of particular utility in the study of heterogeneity in microbial populations. This review seeks to highlight the role of flow cytometric analyses in studies of microbial heterogeneity, drawing wherever possible on recently published research articles. Whilst microbial heterogeneity is well documented in both natural and laboratory environments, the underlying causes are less well understood.

Monitoring of complex industrial bioprocesses for metabolite concentrations using modern spectroscopies and machine learning: application to gibberellic acid production.

Two rapid vibrational spectroscopic approaches (diffuse reflectance-absorbance Fourier transform infrared [FT-IR] and dispersive Raman spectroscopy), and one mass spectrometric method based on in vacuo Curie-point pyrolysis (PyMS), were investigated in this study. A diverse range of unprocessed, industrial fed-batch fermentation broths containing the fungus Gibberella fujikuroi producing the natural product gibberellic acid, were analyzed directly without a priori chromatographic separation. Partial least squares regression (PLSR) and artificial neural networks (ANNs) were applied to all of the information-rich spectra obtained by each of the methods to obtain quantitative information on the gibberellic acid titer.

Quorum sensing and Chromobacterium violaceum: exploitation of violacein production and inhibition for the detection of N-acylhomoserine lactones.

Quorum sensing relies upon the interaction of a diffusible signal molecule with a transcriptional activator protein to couple gene expression with cell population density. In Gram-negative bacteria, such signal molecules are usually N-acylhomoserine lactones (AHLs) which differ in the structure of their N-acyl side chains. Chromobacterium violaceum, a Gram-negative bacterium commonly found in soil and water, produces the characteristic purple pigment violacein.