The cellular composition of the blood and haematopoietic organs of turbot Scophthalmus maximus L.

The cellular composition of the blood, anterior kidney, spleen and thymus of turbot Scophrhalmus maximus L., aged 1 + was determined. Ninety-four per cent of blood cells belonged to the erythrocyte lineage of which 82% were mature erythrocytes. The leucocytes, which represented 4.5% of the blood cells, were mainly lymphocytes (50%). The presence of crythroblasts in the anterior kidney and the spleen demonstrated an erythropoietic activity in both organs. However, this activity appeared to be prevalent in the spleen which also appeared to act as a storage zone for erythrocytes and as the centre point for thrombopoiesis. Although 96% of the anterior kidney cells were leucocytes, the number of white cells per gram of organ was higher in the spleen.     

Antioxidant enzyme activities in embryologic and early larval stages of turbot

The antioxidant enzymes superoxide dismutase (SOD; EC 1.15.1.1), catalase (EC 1.11.1.6), selenium-dependent glutathione peroxidase (SeGPX; EC 1.11.1.9), glutathione reductase (EC 1.6.4.2) and DT-diaphorase (EC 1.6.99.2), plus total GPX activity (sum of SeGPX and Se-independent GPX activities), were studied in 13 500 g supernatants of embryos and 3-day and 11-day post-hatch larvae of turbot Scophthalmus maximus L. SOD activity decreased progressively during development from embryos to 11-day-old larvae, indicative of a decreased need to detoxify superoxide anion radical (O₂⁻). In contrast, catalase, SeGPX and glutathione reductase activities increased progressively from embryos to 11-day-old larvae, indicative of an increased need to metabolize hydrogen peroxide (H₂O₂) and organic peroxides. Consistent with the latter changes, levels of lipid peroxides (i.e. thiobarbituric acid reactive substances) increased 13-fold from embryos to 3-day-old larvae, whilst total peroxidizable lipid was indicated to decrease. Increases were seen for NADPH-dependent DT-diaphorase (after hatching) and total GPX (between 3 and 11 days post-hatch) activities, whilst no change was found in NADH-dependent DT-diaphorase activity. Overall, the results demonstrate a capacity for early life-stages of S. maximus to detoxify reactive oxygen species (O₂⁻ and H₂O₂) and other pro-oxidant compounds (organic peroxides, redox cycling chemicals). Furthermore, qualitative and quantitative antioxidant changes occur during hatching and development, possibly linked to such events as altered respiration rates (SOD changes) and tissue reorganization and development (catalase, SeGPX, lipid peroxidation).     

Localization of chitinolytic enzymes in blood of turbot, Scophthalmus maximus, and their possible roles in defence

The intracellular localizations ofchitinase and β-N-acetylglucosaminidase were detected in turbot blood smears, using a novel method employing fluorogenic substrates. The two enzymes showed different distributions, with chitinase being more generally distributed and N-acetylglucosaminidase being strongly associated with distinct intracellular bodies, probably lysosomes. The fluorogenic substrates were used to analyse soluble and membrane fractions of homogenates of red and white blood cells prepared on Percoll gradients. In the leucocytes, the chitinase and N-acetylglucosaminidase activities were mostly in the soluble fraction. In the erythrocytes the activities were lower, at about one-hundredth and one-tenth specific activities, respectively, and were distributed between soluble and membrane-bound fractions at about 2 : 1 and 3 : 1, respectively. In contrast, lysozyme had a soluble distribution in leucocytes and was not detected in erythrocytes. Plasma was rich in chitinase and lysozyme activities but had no detectable N-acetylglucosaminidase. Two possible roles for the chitinolytic enzymes are discussed: defence against pathogens and processing of glycoproteins or glucosaminoglycans. Evidence for a defence role for the chitinase and lysozyme is provided by demonstrating that they had inhibitory activity against the chitinous fungus Mucor mucedo .     

Population genetic structure of turbot (Scophthalmus maximus L., 1758) in the Black Sea

Turbot, Scophthalmus maximus, is a commercially important demersal flatfish species distributed throughout the Black Sea. Several studies performed locally with a limited number of specimens using both mitochondrial DNA (mtDNA) and microsatellite markers evidenced notable genetic variation among populations. However, comprehensive population genetic studies are required to help management of the species in the Black Sea. In the present study eight microsatellite loci were used to resolve the population structure of 414 turbot samples collected from 12 sites across the Black Sea. Moreover, two mtDNA genes, COI and Cyt-b, were used for taxonomic identification. Microsatellite markers of Smax-04 and B12-I GT14 were excluded from analysis due to scoring issues. Data analysis was performed with the remaining six loci. Loci were highly polymorphic (average of 17.8 alleles per locus), indicating high genetic variability. Locus 3/20CA17, with high null allele frequency (>30%), significantly deviated from HW equilibrium. Pairwise comparison of the F_ST index showed significant differences between most of the surveyed sampling sites (P < 0.01). Cluster analysis evidenced the presence of three genetic groups among sampling sites. Significant genetic differentiation between Northern (Sea of Azov and Crimea) and Southern (Turkish Black Sea Coast) Black Sea sampling sites were detected. The Mantel test supported an isolation by distance model of population structure. These findings are vital for long-term sustainable management of the species and development of conservation programs. Moreover, generated mtDNA sequences would be useful for the establishment of a database for S. maximus.     

Highways are a threat for giant armadillos that underpasses can mitigate

We report 24 records of giant armadillo roadkill on Brazilian highways in the Cerrado, Pantanal and Amazon biomes illustrating that highways are a threat to this species. However, we also documented the species using underpasses, demonstrating that these structures could help to reduce the risk of roadkill for giant armadillos.     

Activation training facilitates gluteus maximus recruitment during weight-bearing strengthening exercises

Given its tri-planar action at the hip, strengthening of gluteus maximus (GMAX) has been advocated as part of rehabilitation and injury prevention protocols for various musculoskeletal conditions. However, recruitment of GMAX during weight-bearing strengthening exercises can be challenging owing to the muscular redundancy at the hip for a given joint motion. The current study sought to determine if a 1-week activation program could result in greater GMAX recruitment during functional strengthening exercises. Pre- and post-training surface electromyography were collected from 12 healthy participants as they performed double- and single-leg squats. Between testing sessions, participants completed a GMAX activation training program consisting of isometric exercises with band resistance (twice per day for 7 days). Following the 1-week activation program, GMAX recruitment was found to increase by 57% during the double-leg squat (p = 0.005, Cohen’s r = 0.73) and 53% during the single-leg squat (p = 0.006, Cohen’s r = 0.70). Implementation of an initial GMAX activation program should be considered to facilitate neuromuscular adaptations that facilitate utilization of GMAX during hip strengthening exercises.     

Genetic population structure of turbot (Scophthalmus maximus L.) supports the presence of multiple hybrid zones for marine fishes in the transition zone between the Baltic Sea and the North Sea

Genetic population structure of turbot (Scophthalmus maximus L.) in the Northeast Atlantic was investigated using eight highly variable microsatellite loci. In total 706 individuals from eight locations with temporal replicates were assayed, covering an area from the French Bay of Biscay to the Aaland archipelago in the Baltic Sea. In contrast to previous genetic studies of turbot, we found significant genetic differentiation among samples with a maximum pairwise FST of 0.032. Limited or no genetic differentiation was found among samples within the Atlantic/North Sea area and within the Baltic Sea, suggesting high gene flow among populations in these areas. In contrast, there was a sharp cline in genetic differentiation going from the low saline Baltic Sea to the high saline North Sea. The data were explained best by two divergent populations connected by a hybrid zone; however, a mechanical mixing model could not be ruled out. A significant part of the genetic variance could be ascribed to variation among years within locality. Nevertheless, the population structure was relatively stable over time, suggesting that the observed pattern of genetic differentiation is biologically significant. This study suggests that hybrid zones are a common phenomenon for marine fishes in the transition area between the North Sea and the Baltic Sea and highlights the importance of using interspecific comparisons for inferring population structure in high gene flow species such as most marine fishes.     

The ageing phenomenon of turbot spermatozoa: effects on morphology, motility and concentration, intracellular ATP content, fertilization, and storage capacities

The deleterious effect of the ageing phenomenon of turbot spermatozoa was investigated in relation to the sampling date. Spermatozoa with a low or highly condensed chromatin and a middle piece containing numerous or a few vesicles were observed simultaneously 80 and 47 days before the beginning of the spawning period of the females. The middle piece of spermatozoa contained few vesicles, 39 days after the end of the reproductive period. At the same date, some spermatozoa appeared in which the plasma membrane was broken. Sperm motility, assessed just after collection in terms of arbitrary motility scores from 0 to 5, was significantly increased both at 10 and 60 s post-activation, for samples collected 18 days after, 25 days before and 9 days after the beginning of the spawning period of the females, respectively compared to samples collected 6 days before, 55 days after and 88 days after the end of this period. A lower short-term storage capacity was recorded at 10 and 60 s post-activation for sperm samples collected 6 days before and 88 days after the end of the reproductive period, respectively compared to 18 days and 9 days after the beginning of the spawning period. At 60 s post-activation, a higher motility of thawed spermatozoa was observed for samples collected 5 days before the beginning of the spawning period (motility recovery index: 86.4 ± 19.4%) compared to 71 days after the end of this period (55.0 ± 12.0%). The fertilizing capacity of sperm samples collected 61 days after the end of the spawning season (66.1 ± 14.6%) was significantly lower than that recorded for samples collected 34 days after the beginning of the spawning period (75.2±9.6%). On the contrary, there was no significant decrease in endogenous ATP content (31 days after the beginning of the spawning period, 14.53 ± 0.84; 48 days after the end of this period, 10.75 ± 5.26 nmol 10^{? 8} spermatozoa). Furthermore, sperm concentration significantly increased between the same dates (respectively 3.3 ± 0.8–9.4±4.8×10⁹ spermatozoa ml^?1).     

Histology,histochemistry and morphometry of the ovary of the adult plains viscacha (Lagostomus maximus) in different reproductive stages

Lagostomus maximus is a South American Hystricognathi rodent whose reproductive behaviour shows characteristics unusual for mammals, such as polyovulation (200–800 oocytes) and a high rate of embryo mortality. Thirty‐six mature females captured in the province of Buenos Aires showed different physiological reproductive stages. Most of them presented a postpartum oestrus in August–September. This characteristic is different from that reported in other geographical areas. The stages considered were: anoestrus, follicular phase, early pregnancy and late pregnancy. The ovaries were light‐pink and smooth and presented a tortuous cord‐like aspect. Many primordial follicles were found in all the females studied. Follicles in different states of maturation and primary and accessory corpora lutea were observed in the cortex. These structures were smaller than those present in other related species. Follicles did not project into the surface of the organ. Calcified follicles of diverse size were found in all the ovaries. Atretic follicles were found in all the stages analysed. Interstitial tissue surrounding the follicles and the corpora lutea was also observed. The number and proportion of different cortical structures varied in the physiological stages analysed. The ovaries of the viscacha have differential characteristics in comparison to other Hystricognathi, some of them related to polyovulation.