Project description:The marbled flounder (Pseudopleuronectes yokohamae) is a commercial flatfish in East Asia. The aim of this study was to improve its sperm cryopreservation protocol based on the vitality assessment of 7-day and 1-year cryopreserved sperm. Four extenders (extender-1: sucrose solution; extender-2: glucose solution; extender-3: fish Ringer's solution; and extender-4: modified fish Ringer's solution) were tested with a combination of five cryoprotectants (CPAs) (dimethyl sulfoxide: Me2SO; glycerol: GLY; ethylene glycol: EG; propylene glycol: PG; and methanol: MeOH) at four different concentrations (5, 10, 12, and 15%). Fluorescent technique was applied to detect the plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), and DNA integrity of fresh and cryopreserved sperm specimens. Fresh sperm was diluted at a ratio of 1:2 (sperm:extender). Post-thaw motility of sperm cryopreserved using 15% Me2SO along with either extender-1 (86.0 ± 5.2%) or extender-2 (85.7 ± 7.1%) was similar (p > 0.05) to that of fresh sperm. Sperm cryopreserved using 12% GLY combined with extender-1 (83.67 ± 6.7%) or extender-2 (83.3 ± 4.7%) showed a similar motility to those cryopreserved with 15% Me2SO, but significantly lower from fresh sperm. The type of straw (0.25 or 0.50 mL) did not show any significant difference (p > 0.05) in post-thaw sperm motility. The highest values of PMI and MMP were observed for 7-day cryopreserved sperm using extender-1 in combination with 15% Me2SO (91.0 ± 2.9% and 90.0 ± 2.0%, respectively) or 12% GLY (90.0 ± 1.3% and 90.0 ± 4.6%, respectively). These results were similar to those of fresh sperm (95.3 ± 2.1% and 92.9 ± 2.5%, respectively). PMI and MMP of 1-year cryopreserved sperm using extender-1 in combination with 15% Me2SO (90.3 ± 2.5% and 89.3 ± 2.1%, respectively) or 12% GLY (90.0 ± 4.4% and 88.7 ± 2.2%, respectively) were significantly similar (p > 0.05) to those of fresh sperm. Sperm DNA integrity did not reveal any significant difference (p > 0.05) between fresh and cryopreserved (7-day and 1-year) sperm. Based on the assessed sperm vitality indicators, a cryopreservation protocol using extender-1 in combination with 15% Me2SO or 12% GLY has potential for hatchery as well as to create a germplasm bank.
| S-EPMC8273914 | biostudies-literature
Project description:The complete mitochondrial genome of Pseudopleuronectes herzensteini
Project description:Winter flounder (Pseudopleuronectes americanus) once supported robust commercial and recreational fisheries in the New York (USA) region, but since the 1990s populations have been in decline. Available data show that settlement of young-of-the-year winter flounder has not declined as sharply as adult abundance, suggesting that juveniles are experiencing higher mortality following settlement. The recent increase of blue crab (Callinectes sapidus) abundance in the New York region raises the possibility that new sources of predation may be contributing to juvenile winter flounder mortality. To investigate this possibility we developed and validated a method to specifically detect winter flounder mitochondrial control region DNA sequences in the gut contents of blue crabs. A survey of 55 crabs collected from Shinnecock Bay (along the south shore of Long Island, New York) in July, August, and September of 2011 showed that 12 of 42 blue crabs (28.6%) from which PCR-amplifiable DNA was recovered had consumed winter flounder in the wild, empirically supporting the trophic link between these species that has been widely speculated to exist. This technique overcomes difficulties with visual identification of the often unrecognizable gut contents of decapod crustaceans, and modifications of this approach offer valuable tools to more broadly address their feeding habits on a wide variety of species.
Project description:The authors investigated the kinetics of transfer of perfluorooctane sulfonate (PFOS) from water, suspended sediment, and bottom sediment to a marine benthic fish, the marbled flounder (Pseudopleuronectes yokohamae). Fish were exposed in 3 treatments to PFOS in combinations of these exposure media for 28 d and then depurated for 84 d. A major part (37-66%) of PFOS in the fish was in the carcass (i.e., whole body minus muscle and internal organs). Three first-order-kinetic models that differed in exposure media, that is, 1) sum of dissolved and particulate phases and sediment; 2) dissolved phase, particulate phase, and sediment; and 3) dissolved phase only, were fitted to the data assuming common rate constants among the treatments. The uptake efficiency of dissolved PFOS at the respiratory surfaces was estimated to be 3.2% that of oxygen, and the half-life of PFOS in the whole body to be 29 d to 31 d. The better fit of models 1 and 2 and the values of the estimated uptake rate constants suggested that the PFOS in suspended and bottom sediments, in addition to that dissolved in water, contributed to the observed body burden of the fish. Based on an evaluation of several possible contributing factors to the uptake of PFOS from suspended and bottom sediments, the authors propose that further investigation is necessary regarding the mechanisms responsible for the uptake.