Transport of amino acids in the splanchnic bed by blood plasma and blood in the preruminant calf]

Three preruminant calves were fitted with catheters in portal and hepatic veins and in a mesenteric artery. Two electromagnetic flowmeter probes were clipped around the portal vein and the hepatic artery. The calves were fed either a diet with a low (L) or a high (R) abomasal emptying rate for dietary proteins. Blood flow and free amino acid levels in plasma (P) and blood (S) were determined before the morning meal and during the following 7 h. In the portal vein, for most amino acids P/S ratios were correlated to the net amino acid balance of the digestive tract measured in plasma. By contrast in the hepatic vein, these ratios were mainly correlated to hepatic balance measured in whole blood. Correlations between digestive tract and hepatic balance calculated using either plasma or whole blood pool were different for some amino acids. This suggests that amino acid exchange between plasma and blood cells is low and absorbed amino acids are mainly transported to the liver by plasma, whereas whole blood rather than plasma is concerned in amino acid exchanges in the liver.     

Detecting non-neutral heterogeneity across a region of DNA sequence in the ratio of polymorphism to divergence

Natural selection, in the form of balancing selection or selective sweeps, can result in a decoupling of the amounts of molecular polymorphism and divergence. Thus natural selection can cause some areas of DNA sequence to have greater silent polymorphism, relative to divergence between species, than other areas. It would be useful to have a statistical test for heterogeneity in the polymorphism to divergence ratio across a region of DNA sequence, one that could identify heterogeneity greater than that expected from the neutral processes of mutation, drift, and recombination. The only currently available test requires that a region be arbitrarily divided into sections that are compared with each other, and the subjectivity of this division could be problematic. Here a test is proposed in which runs of polymorphic and fixed sites are counted, where a "run" is a set of one or more sites of one type preceded and followed by the other type. The number of runs is smaller than otherwise expected if polymorphisms are clumped together. By simulating neutral evolution and comparing the observed number of runs to the simulations, a statistical test is possible which does not require any a priori decisions about subdivision.      

The Influence of Antimicrobial Peptides and Mucolytics on the Integrity of Biofilms Consisting of Bacteria and Yeasts as Affecting Voice Prosthetic Air Flow Resistances

The integrity of biofilms on voice prostheses used to rehabilitate speech in laryngectomized patients causes unwanted increases in airflow resistance, impeding speech. Biofilm integrity is ensured by extracellular polymeric substances (EPS). This study aimed to determine whether synthetic salivary peptides or mucolytics, including N-acetylcysteine and ascorbic acid, influence the integrity of voice prosthetic biofilms. Biofilms were grown on voice prostheses in an artificial throat model and exposed to synthetic salivary peptides, mucolytics and two different antiseptics (chlorhexidine and Triclosan). Synthetic salivary peptides did not reduce the air flow resistance of voice prostheses after biofilm formation. Although both chlorhexidine and Triclosan reduced microbial numbers on the prostheses, only the Triclosan-containing positive control reduced the air flow resistance. Unlike ascorbic acid, the mucolytic N-acetylcysteine removed most EPS from the biofilms and induced a decrease in air flow resistance.     

Does fin damage allow discrimination among wild,escaped and farmed Sparus aurata (L.) and Dicentrarchus labrax (L.)?

The present study compares fin damages in gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) according to their wild, escaped or farmed origins. In addition, the potential applicability of fin condition indices (Fin Erosion Index ‘FEI’ and Fin Splitting Index ‘FSI’) as identification tools is discussed. Farmed seabream fins evidenced more erosion and splitting (FEI ± SD: 2.1 ± 0.3; FSI ± SD: 1.9 ± 0.6) than wild seabream fins (FEI: 0.8 ± 0.6; FSI: 1.2 ± 0.9), a result of farming conditions in open‐sea cages. Escaped seabream fin erosion was between that of farmed and wild seabream (FEI: 1.6 ± 0.4), which could indicate that fins in farmed fish recover over time from farming abrasions once they are in the wild. However, the fins of escaped seabream seem to be weaker than those of the wild fish, and therefore might be more susceptible to suffer other types of erosion such as splitting or nipping (FSI: 2.3 ± 0.7). No significant differences were found in seabass FEI according to their origins, although wild seabass presented significantly more split caudal fins (FSI: 3.3 ± 2.8) than the farmed seabass (FSI: 1.2 ± 1.1) and escapees (FSI: 2.5 ± 1.6). Therefore, FEI for seabream could be used as tools not only to distinguish between wild and farmed fish, but also to identify recent escapees, improving further assessments on the contribution of seabream escapees in fishery landings. However, the healing potential of damaged fins must be considered for the proper identification of escapees. Use of fin condition indices from both species could be helpful for aquaculture management, to assess fish welfare in fish farms stocks, and improve the knowledge of handling, stock densities and open‐sea cage environment conditions.     

Automated large-volume sample stacking procedure to detect labeled peptides at picomolar concentration using capillary electrophoresis and laser-induced fluorescence detection

We have developed an automated large-volume sample stacking (LVSS) procedure to detect fluorescein isothiocyanate-labeled peptides in the picomolar range. The injection duration is 10 min at 50 mbar to fill 62% of the capillary volume to the detection cell. The calculated limit of detection (S/N=3), filling 1% of the capillary volume, is 74 pM for bradykinin and 45 pM for L-enkephalin with samples diluted in water and analyzed in a 50 mM borate buffer, pH 9.2. With the automated LVSS system, the limits of detection are 7 pM for bradykinin, 3 pM for L-enkephalin and 2 pM for substance P. LVSS is shown to be quantitative from 500 to 10 pM.