Mobile epibenthic fauna consume organic waste from coastal fin-fish aquaculture.

Organic waste released from fin-fish aquaculture is being dispersed further as industry growth has led to the expansion of open net cages in dynamic coastal locations. Here we investigate the response of three mobile epibenthic invertebrates (brittle stars, urchins and brown crabs), whose natural habitats overlap with large scale coastal salmon farming. Using fatty acids and stable isotopes, we found these organisms displayed decreases in δ13C and δ15N and elevated levels of C18 fatty acids reflective of terrestrial components of fin-fish feeds. Furthermore, we found these three species consume aquaculture organic waste not only directly adjacent to the farm vicinity (0-20 m from cage edge) but up to 1 km away in the case of brittle stars and brown crabs. As aquaculture feeds shift to contain more terrestrial ingredients, the biochemistry of fauna feeding on organic waste is also being shifted, the result of these changes is currently unclear.

Inhibitory effects of grape seed extract on growth, quorum sensing, and virulence factors of CDC "top-six" non-O157 Shiga toxin producing E. coli.

Non-O157 Shiga toxin producing Escherichia coli (STECs) have become a growing concern to the food industry. Grape seed extract (GSE), a byproduct of wine industry, is abundant in polyphenols that are known to be beneficial to health. The objective of this study was to evaluate the effect of GSE on the growth, quorum sensing, and virulence factors of Centers for Disease Control and Prevention (CDC) "top-six" non-O157 STECs. Minimal inhibitory concentration (MIC) of GSE was 2mg/ml against E. coli O26:H11, and 4mg/ml against the other non-O157 STECs tested. Minimal bactericidal concentration (MBC) was the same as MIC for all six non-O157 STECs tested. At 5×10(5)CFU/ml inoculation level, 4mg/ml GSE effectively inhibited the growth of all tested strains, while 0.25-2mg/ml GSE delayed bacterial growth. At a higher inoculation level (1×10(7)CFU/ml), GSE had less efficacy against the growth of the selected six non-O157 STECs. Its impact on bacterial virulence was then assessed at this inoculation level. Autoinducer-2 (AI-2) is a universal signal molecule mediating quorum sensing (QS). GSE at concentration as low as 0.5mg/ml dramatically reduced AI-2 production of all non-O157 STECs tested, with the inhibitory effect proportional to GSE levels. Consistent with diminished QS, GSE at concentration of 0.125mg/ml caused marked reduction of swimming motility of all motile non-O157 STECs tested. In agreement, GSE treatment reduced the production of flagella protein FliC and its regulator FliA in E. coli O103:H2 and E. coli O111:H2. Furthermore, 4mg/ml GSE inhibited the production of Shiga toxin, a major virulence factor, in E. coli O103:H2 and E. coli O111:H2. In summary, GSE inhibits the growth of "top-six" non-O157 STECs at the population level relevant to food contamination. At higher initial population, GSE suppresses QS with concomitant decrease in motility, flagella protein expression and Shiga toxin production. Thus, GSE has the potential to be used in food industry to control non-O157 STEC.

Conductivity and voltammetry in liquid and supercritical halogenated solvents.

A previous study of the voltammetry of ferrocene in liquid and supercritical chlorodifluoromethane revealed electrochemically reversible behavior. However, shifts in the half-wave potential as a function of fluid conditions were observed which were tentatively attributed to ohmic distortion due to changes in fluid resistance. To more completely understand the voltammetry in this fluid, conductivity measurements have been made for a range of fluid conditions. Additionally, a second reference couple, cobaltocenium hexafluorophosphate, has been introduced, and the difference in half-wave potentials between the two redox couples has been examined as a function of fluid conditions. In the liquid, the difference in the half-wave potentials of the two couples corrected for ohmic distortion decreases as the fluid temperature increases (25-85 °C) at constant pressure (5.2 MPa). In the supercritical fluid at constant temperature (115 °C), the difference in the half-wave potentials corrected for ohmic distortion is constant at 1.276 ± 0.005 V over a considerable range of fluid pressure (10-30 MPa). Ion aggregation in the supercritical fluid is indicated both by the conductivity measurements and by the rather large hydrodynamic radius of cobaltocenium computed from the voltammograms. Preliminary voltammetry in supercritical trifluoromethane is also presented.

Hemispheric asymmetries and schizophrenia.

Investigators have hypothesized that schizophrenic patients have abnormal left hemisphere function or deviations from normal function asymmetry. It has also been suggested that schizophrenic patients have reversal of normal structural asymmetries. The authors measured frontal and occipital petalia and frontal and occipital width of each hemisphere on the CT scans of 43 right-handed schizophrenic patients and 40 right-handed control subjects. There were no significant differences in structural asymmetry between the groups. The 8 left-handed schizophrenic patients may have had abnormal functional asymmetries; their mean ventricular-brain ratio, a possible indirect indicator of cerebral atrophy, was higher than that of the right-handed patients.

Ventricular enlargement in schizophrenia: definition and prevalence.

Ventricular enlargement in schizophrenia as measured by ventricular-brain ratio (VBR) has been described by three different research groups. Because of the possibility that the samples might not be representative of the broad population of schizophrenic patients, questions have been raised about generalizability. The authors report on ventricular enlargement in a rigorously defined but representative sample of schizophrenic patients intermittently hospitalized but living in the community. They provide additional evidence that ventricular enlargement does occur in schizophrenic patients, although not at rates as high as those previously reported. Issues related to the definition of ventricular enlargement, as well as the effects of sampling and choice of a control group, are discussed.

Ventricular enlargement in schizophrenia: relationship to positive and negative symptoms.

The authors explored the clinical correlates of ventricular enlargement in schizophrenia by comparing 16 patients with "large" ventricles (ventricles more than I SD above the control mean) with 16 patients with the smallest ventricles from a sample of 52 schizophrenic patients. Patients with ventricular enlargement showed some impairment in the sensorium and had a preponderance of "negative" symptoms (e.g., alogia, affective flattening, avolition, anhedonia), while those with small ventricles were characterized by "positive" symptoms (e.g., delusions, hallucinations, positive formal thought disorder, bizarre behavior). These findings suggest that combining a measure of brain structure with the clinical picture may provide a useful new approach to the classification of schizophrenia.