The fishery for black scabbardfish (Aphanopus carbo Lowe, 1839) in the Portuguese continental slope

The black scabbardfish is a deep-sea teleost species with high commercial interest in the NE Atlantic. While it is caught by large offshore trawlers in the North of Europe, in the south it is captured by artisanal longlines. On the Portuguese continental slope, in the south of ICES Division IXa, a longline fleet has been engaged in the capture of black scabbardfish for more than 20 years. This paper reviews and analyses the features of this fishery from a temporal perspective based on information from different data sources. The fishery is based on the port of Sesimbra, where a family type fishing community strives to keep catches profitable without altering the artisanal features that characterizes the fleet. Although the fleet has experienced some technical improvements through time, the fishing operations and strategy have changed very little. Fishing occurs at particular areas on the slope, where individual vessels have their own fishing grounds. Annual landings surpassed 4,000 tonnes in the early 1990’s, but decreased to nearly 3,000 tonnes and have remained at this level since 2000. The length structure of the landings was stable from 2000 to 2005, with a modal (total length) class of 1,090 mm. Monthly landings per unit effort estimated by a generalized linear model did not present any marked trend for the period 2000–2004. The landings reported in mainland Portugal were compared with the ones from other regions of the ICES area and the different characteristics of the fisheries operating in the north and south of Europe were analysed.     

Food restriction prevents the loss of isosafrole inducible cytochrome P-450 mRNA and enzyme levels in aging rats

The influence of food restriction (FR) on the drug-inducible capacity of liver microsomal cytochrome P-450s IA1, IA2 and IIB1 and IIB2 was studied in 20-month-old male Fischer-344 rats. ELISA and Western Blotting revealed that the induction of the cytochrome P-450-IA1/IA2 and P-450-IIB1/IIB2 enzymes was considerably higher in the liver microsomes of FR rats than in their ad libitum (AL) fed counterparts. In order to determine whether the higher P-450 enzyme levels in FR rats were a reflection of an increased synthesis rate or a stabilization of these enzymes, hybridization studies were performed with a cDNA probe for P-450-IIB1/IIB2. These studies show markedly higher levels of P-450-IIB1/IIB2 mRNAs in the livers of FR rats as compared to AL animals. These results suggest that it is possible to prevent the age-dependent loss of drug-induced cytochrome P-450s by 40% dietary restriction which suggest FR may improve the drug-metabolizing capacity during aging.     

Mechanisms of Hemolysis Induced by Copper

An excess of copper is the cause of hemolysis in a number of clinical conditions. Incubation of human erythrocyte (RBC) suspensions with copper (II) causes the formation of methemoglobin, lipid peroxidation and hemolysis.

A new variant of the thiobarbituric acid (TBA) method, which minimizes the formation of interfering chromophores, was used to detect lipid peroxidation. Lipid peroxidation precedes hemolysis and the antioxidant vitamins C and E, which inhibit lipid peroxidation, also inhibit hemolysis. Consequently lipid peroxidation appears to be the cause of RBC destruction. Lipid peroxidation arises mostly from the oxidation of oxyhemoglobin by copper as it is inhibited in RBCs with carbon monoxyhemoglobin or methemoglobin. A direct interaction of copper with the red cell membrane seems to play only a minor role. Copper effects depend on the presence of free SH groups. Lipid peroxidation is probably initiated by activated forms of oxygen as it is increased by an inhibitor of catalase and reduced by hydroxyl radical scavengers. With higher copper concentrations hemolysis is greater: its mechanism appears different as lipid peroxidation is smaller but hemoglobin alterations, namely precipitation, are more pronounced.     

Chromosome variability in Brazilian populations of Drosophila buzzatii (Diptera, Drosophilidae).

Analysis of 28 strains of Drosophila buzzatii from six different localities revealed that populations from southern Brazil apparently differ from northeastern populations in chromosome structure. Of the 16 polymorphic chromosome inversions detected in this species, only two (2j and 5c2) were present in southern populations. The Northeastern populations were the first of this species found not to have the 2j inversion. This suggests that the populations of Drosophila buzzatii may have lost chromosome polymorphism during dispersion, supporting the idea that the current geographic distribution of this species in South America is due to active dispersion.     

Three new species of oxyuroid nematodes,including two new genera,from freshwater catfishes in Brazil

Three new oxyuroid nematode species of the family Pharyngodonidae are described from the intestine of freshwater catfishes in Brazil (River Paraná), two of them being representatives of new monotypic genera: Ichthyouris brasiliensis n. sp. from Pterygoplichthys aculeatus, Brasilnema pimelodellae n. g., n. sp. from Pimelodella gracilis, and Parasynodontisia petterae n. g., n. sp. from Rhinelepis aspera. I. brasiliensis n. sp. differs from the only other congeneric species, I. ro, mainly in the absence of a pair of plate-like structures in the male caudal region, shorter caudal alae, the presence of a pair of conspicuous lateral spines at the level of the anal opening in the female and by other features. Brasilnema n. g. is characterised mainly by a hexagonal oral opening, a broad buccal capsule containing three teeth, a simple spicule and an amphidelphic uterus, whereas Parasynodontisia n. g. is characterised by a triangular oral opening and an amphidelphic uterus in the female; both genera possess six small, triangular, circumoral lamellae slightly raised above the apical surface. The paper includes a key to the pharyngodonid genera whose species are parasitic in fishes.     

A mathematical model of rabbit cortical thick ascending limb of the Henle's loop

A mathematical version of the cell model of the cortical thick ascending limb of the rabbit proposed by Greger and Schlatter ((1983) Pfügers Arch. 396, 325-334) is described. Available data are sufficient to compute the most important parameters. Simulations of experiments with perfused tubules in which the transepithelial voltage and conductance, and the intracellular electrical potential were measured in the course of ionic substitutions in the perfusing baths or treatment with ouabain or furosemide are in good agreement with the experimental results with the exception of those relating to dilution potential experiments. The model can be used in the analysis and planning of experiments and is capable of predicting the instantaneous values of ionic fluxes and intracellular concentrations and of cell volume.