鱼儿趣闻

鱼的种类可谓多矣!有看见过的,有听见过的还有没有看见过也没有听见过的. 这里辑录数种,名曰:鱼儿趣闻.

银鲳

银鲳属鲈形目、鲳亚目、鲳科、鲳属。俗称镜鱼、平鱼(河北、山东)；车片鱼、长林(江苏、浙江)，白鲳(福建、台湾、广东)。

Genetic mapping and QTL analysis for body weight in Jian carp (Cyprinus carpio var.Jian) compared with mirror carp (Cyprinus carpio L.)

We report the genetic linkage map of Jian carp(C yprinus carpio var. Jian). An F1 population comprising 94 Jian carp individuals was mapped using 254 microsatellite markers. The genetic map spanned 1 381.592 c M and comprised 44 linkage groups,with an average marker distance of 6.58 c M. We identified eight quantitative trait loci(QTLs) for body weight(BW) in seven linkage groups,explaining 12.6% to 17.3% of the phenotypic variance. Comparative mapping was performed between Jian carp and mirror carp( Cyprinus carpio L.),which both have 50 chromosomes. One hundred and ninety-eight Jian carp marker loci were found in common with the mirror carp map,with 186(93.94%) showing synteny. All 44 Jian carp linkage groups could be one-to-one aligned to the 44 mirror carp linkage groups,mostly sharing two or more common loci. Three QTLs for BW in Jian carp were conserved in mirror carp. QTL comparison suggested that the QTL confidence interval in mirror carp was more precise than the homologous interval in Jian carp,which was contained within the QTL interval in Jian carp. The syntenic relationship and consensus QTLs between the two varieties provide a foundation for genomic research and genetic breeding in common carp.

Improved Whale Optimization Algorithm Based on Mirror Selection

Since traditional whale optimization algorithms have slow convergence speed,low accuracy and are easy to fall into local optimal solutions,an improved whale optimization algorithm based on mirror selection(WOA-MS)is proposed. Specific improvements includes:(1)An adaptive nonlinear inertia weight based on Branin function was introduced to balance global search and local mining.(2) A mirror selection method is proposed to improve the individual quality and speed up the convergence. By optimizing several test functions and comparing the experimental results with other three algorithms,this study verifies that WOA-MS has an excellent optimization performance.

Moving Objects Detection Using Intersecting Cortical Model in Enhanced Fish-eye Image

A new method of the moving objects detection using the enhanced fish-eye lens and the intersecting cortical model （ICM） algorithm is proposed. The improved fish-eye lens is designed through controlling the entrance pupils of the lens. This lens has an ultra field of view about 183 degrees, and can image an ellipse picture on the 4 ： 3 rectangular CCD surface, which increases the CCD utilization and the image resolution. The ICM is a model based on pulse coupled neural network（PCNN） which is espeeially designed for image processing. It is derived from several visual cortex models and is basically the intersection of these models. The theoretical foundation of the ICM is given. An improved ICM algorithm in which some parameters are modified is used to detect moving objects specially. The experiment indicated that moving objects can be detected reliably and efficiently using ICM algorithm from the elliptical fish-eye image. It can be used in the field of traffic monitoring and other security domains.

FURTHER OBSERVATION OF THE SPERMATOZOA OF LEFT-EYE FLOUNDER PARALICHTHYS OLIVACEUS BY ELECTRONIC MICROSCOPY

The spermatozoon ultrastructure of left-eye flounder, Paralichthys olivaceus, was observed by electronic microscopy, and shown to consist of head, midpiece and tail. Some nuclear vacuoles were observed inside and along the outer part of the nucleus and double-membrane structures were observed between the nuclear membrane and plasma membrane. The sperm sleeve consisted of four independent parts and had more than four mitochondria. Along the sperm tail there were wing-like lateral fins.

Gill Epithelium Ultrastructure of Oreochromis niloticus Exposed to Gradual Raised Salinity

Fish gill is a multifunctional organ with role in acid-base balance, elimination of nitrogen waste and mainly gas exchange and ion regulation. There is a high energetic coast for ionregulation in freshwater fish maintained in salt water but a raise in growing taxes was observed for some species. The freshwater Nile tilapia, Oreochromis niloticus, is widely used in aquaculture farmers and the aim of this study was to investigate the changes on the gill filaments nltrastructure in fish kept under different salinities. Alevins were obtained and transported to laboratory of studies in animal stress Federal University of Paran~. Established groups in 0%0, 16%0 and 32%0 salt water with 12 animals in each one. After 30 days of exposition, the animals were anesthetized and the second gill arches were dissected and processed for scanning and transmission electron microscopy. The mitochondrial rich cells fractional area and density in the gill epithelia were determinated. The under scanning electron microscopy （SEM） in 0%0 salinity group reveal changes in the apical ridge of mitochondrial rich cells （MRCs）. In all other groups, the observations revealed numerous crypts disposed mainly in the filament epithelia. In transmission electron microscopy （TEM） two distinct types of MRCs were observed. The data of MRCFA and density revealed in 0%0 and 16%0 values significantly elevated in comparison to 32%0. Despite these lower values, the density in the gill epithelia was higher. The main differences found between the groups revealed that fish exposed to 16%o salinity have less MRCs aperture to the environment and are less related to ion regulation process.

Optimization of Protectant, Salinity and Freezing Condition for Freeze-Drying Preservation of Edwardsiella tarda

Novel preservation condition without ultra-low temperature is needed for the study of pathogen in marine fishes. Freeze-drying is such a method usually used for preservation of terrigenous bacteria. However, studies using freeze-drying method to preserving marine microorganisms remain very limited. In this study, we optimized the composition of protectants during the freeze-drying of Edwardsiella tarda, a fish pathogen that causes systemic infection in marine fishes. We found that the optimal composition of protectant mixture contained trehalose(8.0%), skim milk(12.0%), sodium citrate(2.0%), serum(12.0%) and PVP(2.0%). Orthogonal and interaction analyses demonstrated the interaction between serum and skim milk or sodium citrate. The highest survival rate of E. tarda was observed when the concentration of Na Cl was 10.0, 30.0 and between 5.0 and 10.0 g L^(-1) for preparing TSB medium, E. tarda suspension and protectant mixture, respectively. When E. tarda was frozen at-80℃ or-40℃ for 6 h, its survival rate was higher than that under other tested conditions. Under the optimized conditions, when the protectant mixture was used during freeze-drying process, the survival rate(79.63%–82.30%) of E. tarda was significantly higher than that obtained using single protectant. Scanning electron microscopy(SEM) image indicated that E. tarda was embedded in thick matrix with detectable aggregation. In sum, the protectant mixture may be used as a novel cryoprotective additive for E. tarda.

Water-trapping and drag-reduction effects of fish Ctenopharyngodon idellus scales and their simulations

In the last decades, surface drag reduction has been re-emphasized because of its practical values in engineering applications,including vehicles, aircrafts, ships, and fuel pipelines. The bionic study of drag reduction has been attracting scholars' attentions. Here, it was determined that the delicate microstructures on the scales of the fish Ctenopharyngodon idellus exhibit remarkable drag-reduction effect. In addition, the underlying drag-reduction mechanism was carefully investigated. First,exceptional morphologies and structures of the scales were observed and measured using a scanning electron microscope and3-dimensional(3D) microscope. Then, based on the acquired data, optimized 3D models were created. Next, the mechanism of the water-trapping effect of these structures was analyzed through numerical simulations and theoretical calculations. It was determined that there are many microcrescent units with certain distributions on its surface. In fact, these crescents are effective in generating the "water-trapping" effect and forming a fluid-lubrication film, thus reducing the skin friction drag effectively.Contrasting to a smooth surface, the dynamics finite-element analysis indicated that the maximum drag-reduction rate of a bionic surface is 3.014% at 0.66 m/s flow rate. This study can be used as a reference for an in-depth analysis on the bionic drag reduction of boats, underwater vehicles, and so forth.

Superresolution imaging of telomeres with continuous wave stimulated emission depletion (STED) microscope

The significant role of telomeres in cells has attracted much attention since they were discovered.Fluorescence imaging is an effective method to study subcellular structures like telomeres.However,the diffraction limit of traditional optical microscope hampers further investigation on them.Recent progress on superresolution fluorescence microscopy has broken this limit.In this work,we used stimulated emission depletion(STED) microscope to observe fluorescence-labeled telomeres in interphase cell nuclei.The results showed that the size of fluorescent puncta representing telomeres under the STED microscope was much smaller than that under the confocal microscope.Two adjacent telomeres were clearly separated via STED imaging,which could hardly be discriminated by confocal microscopy due to the diffraction limit.We conclude that STED microscope is a more powerful tool that enable us to obtain detailed information about telomeres.