Calcium-dependent behavioural responses to acute copper exposure in Oncorhynchus mykiss.

Using rainbow trout Oncorhynchus mykiss, the present study demonstrated that: (1) calcium (Ca) increased the range of copper (Cu) concentrations that O. mykiss avoided; (2) Ca conserved the maintenance of pre-exposure swimming activity during inescapable acute (10 min) Cu exposure. Data showed that when presented with a choice of Cu-contaminated water (ranging from 0 to 454 µg Cu l⁻¹ ) and uncontaminated water in a choice tank, O. mykiss acclimated and tested at low Ca concentration (3 mg Ca l⁻¹ avoided the 10 µg Cu l⁻¹ only. By contrast, O. mykiss acclimated and tested at high Ca concentration (158 mg Ca l⁻¹) avoided all the Cu concentrations ≥37 µg⁻¹. The Cu avoidance was connected with increased spontaneous swimming speed in the Cu-contaminated water. When subjected to inescapable Cu exposure (35 µg Cu l⁻¹), O. mykiss acclimated and tested at low Ca concentration reduced their spontaneous swimming speed, whereas no response was observed in O. mykiss acclimated and tested at high Ca concentration. Collectively, the data support the conclusion that in O. mykiss the behavioural responses to acute Cu exposure are Ca-dependent.

Behaviour of rainbow trout Oncorhynchus mykiss presented with a choice of normoxia and stepwise progressive hypoxia.

The objective of this study was to identify behavioural adjustments leading to avoidance of hypoxia. Using the oxygen-sensitive species rainbow trout Oncorhynchus mykiss as a model, individual fish were recorded while moving freely between two sides of a test arena: one with normoxia and one with stepwise progressive hypoxia [80-30% dissolved oxygen (DO) air saturation]. The results demonstrated a gradual decrease in the total time spent in hypoxia starting at 80% DO air saturation. At this DO level, the avoidance of hypoxia could not be attributed to changes in spontaneous swimming speed, neither in normoxia nor in hypoxia. Reducing the DO level to 60% air saturation resulted in decreased spontaneous swimming speed in normoxia, yet the number of trips to the hypoxic side of the test arena remained unchanged. Moreover, data revealed increased average residence time per trip in normoxia at DO levels ≤60% air saturation and decreased average residence time per trip in hypoxia at DO levels ≤50% air saturation. Finally, the spontaneous swimming speed in hypoxia increased at DO levels ≤40% air saturation and the number of trips to hypoxia decreased at the 30% DO air saturation level. Thus, avoidance of the deepest hypoxia was connected with a reduced number of trips to hypoxia as well as decreased and increased spontaneous swimming speed in normoxia and hypoxia, respectively. Collectively, the data support the conclusions that the mechanistic basis for avoidance of hypoxia may (1) not involve changes in swimming speed during mild hypoxia and (2) depend on the severity of hypoxia.

Short communication: Effects of dietary nitrogen concentration on messenger RNA expression and protein abundance of urea transporter-B and aquaporins in ruminal papillae from lactating Holstein cows.

To test the hypothesis that dietary N concentrations affect gut epithelial urea transport by modifying the expression of urea transporter B (UT-B) and aquaporins (AQP), the mRNA expression and protein abundance of UT-B and AQP3, AQP7, AQP8, and AQP10 were investigated in ruminal papillae from 9 lactating dairy cows. Ruminal papillae were harvested from cows fed low N (12.9% crude protein) and high N (17.1% crude protein) diets in a crossover design with 21-d periods. The mRNA expression was determined by real-time reverse transcription-PCR and protein abundance by immunoblotting. The mRNA expression of UT-B was not affected by dietary treatment, whereas mRNA expression of AQP3, 7, and 10 were greater in the high N compared with the low N fed cows. Using peptide-derived rabbit antibodies to cow AQP3, 7, and 8, immunoblotting revealed bands of approximately 27, 27, and 24 kDa in ruminal papillae, respectively. A peptide-derived chicken antibody to cow UT-B detected a band of approximately 30 to 32 kDa in ruminal papillae. The abundance of UT-B and AQP3 and 7 were not affected by dietary treatment. In contrast, the abundance of AQP8 was greater in high N compared with low N diets. In conclusion, AQP3, 7, and 8 were found to be expressed in bovine rumen papillae. None of the investigated transcripts or proteins correlated to the increased rumen epithelial urea permeability observed with low dietary N concentration.

Effects of food deprivation on refuge use and dispersal in juvenile North Sea houting Coregonus oxyrinchus under experimental conditions.

This study tested the influence of energetic state on refuge use and dispersal in juvenile North Sea houting Coregonus oxyrinchus in an artificial stream. Food-deprived fish spent more time outside refuges than well-fed fish; however, the well-fed fish initiated dispersal faster than the food-deprived fish. The results may indicate state-dependent refuge use and dispersal in C. oxyrinchus.

Identification of Trichoderma strains by image analysis of HPLC chromatograms.

Forty-four Trichoderma strains from water-damaged building materials or indoor dust were classified with chromatographic image analysis on full chromatographic matrices obtained by high performance liquid chromatography with UV detection of culture extracts. The classes were compared with morphological identification and rDNA sequence data, and for each class all strains were of the same identity. With all three techniques each strain--except one--was identified as the same species. These strains belonged to Trichoderma atroviride (nine strains), Trichoderma viride (three strains), Trichoderma harzianum (10 strains), Trichoderma citrinoviride (12 strains), and Trichoderma longibrachiatum (nine strains). The odd strain was identified as Trichoderma hamatum by morphology and rDNA sequencing, but not by image analysis as no reference strains of this species were included. It is concluded that the secondary metabolite profile contains sufficient information for classification and species identification.

Perceptions of house officers who use physician order entry.

OBJECTIVE: Describe the perceptions of housestaff physicians about their experience using computerized physician order entry (POE) in hospitals. METHODS: Qualitative study using data from participant observation, focus groups, and both formal and informal interviews. Data were analyzed by three researchers using a grounded approach to identify patterns and themes in the texts. RESULTS: Six themes were identified, including housestaff education, benefits of POE, problems with POE, feelings about POE, implementation strategies, and the future of POE. CONCLUSION: House officers felt that POE assists patient care but may undermine education. They found that POE works best when tailored to fit local and individual workflow. Implementation strategies should include mechanisms for engaging housestaff in the decision process.