ABSTRACT
To analyze the feeding habits and trophic level of jellyfish (Rhopilema esculentum), Chinese shrimp (Fenneropenaeus chinesis), grass shrimp (Penaeus monodon), and clam (Ruditapes philippinarum), and the food web structure in marine aquaculture pond, we measured the δ13C and δ15N values of the four species and different feed from May to September in 2017. The average proportional contribution of different feed to the four species were analyzed using the IsoSource linear mixture model. The results showed that zooplankton was the main food source to jellyfish, Engraulis japonicus was the main food source to the two shrimp species, and the phytoplankton, benthic diatoms and dejecta of the two shrimp species were the main food source to the clam. The trophic level of the clam ranged from 2.64 to 2.95, with a mean value of 2.84. The trophic level of jellyfish ranged from 2.78 to 3.27, with a mean value of 3.06. the grass shrimp ranged from 3.03 to 3.54, with a mean value of 3.25. The trophic level of Chinese shrimp ranged from 3.76 to 4.40, with a mean value of 3.95. Results of comprehensive analysis showed that the clam was the primary consumer, jellyfish was the secondary consumer, and shrimps were the predators. Jellyfish filtered the dejecta of the two kinds of prawns and improved water quality of the polyculture pond to a certain extent.
Subject(s)
Food Chain , Ponds , Animals , Nitrogen Isotopes/analysis , Shellfish , ZooplanktonABSTRACT
AFLP markers were used to construct the primary linkage map in a family of Mizuhopecten yessoensis. A total of 1 855 markers were generated in two parents and 52 progenies of the mapping family by using 56 AFLP primer combinations. Among the 1 855 markers, 598 were polymorphic and 354 were in agreement with the Mendelian segregating ratio of 1:1. Markers segregated according to Mendelian 1:1 ratio (P>0.05) and 23 distorted markers (0.01Subject(s)
Amplified Fragment Length Polymorphism Analysis
, Crosses, Genetic
, Genetic Linkage
, Pectinidae/genetics
, Animals
, DNA/analysis
, Female
, Genetics, Population
, Japan
, Male
, Polymorphism, Genetic
ABSTRACT
MYP (Major yolk protein) gene expression at transcription level in different stages of gonad of sea urchin Strongylocentrotus intermedius and hybrids (S. intermediusfemale symbolxS. nudusmale symbol) was analyzed by real-time RT-PCR. Based on normalization with 18S rRNA levels, the comparative quantities of MYP expression were determined. The expression of MYP gene in gonad showed little difference between female and male. MYP gene expression was decreased rapidly in the gonad of S. intermedius at different stages, and slowly in hybrids. The comparative quantities of MYP expression in the gonads of S. intermedius were decreased from 44.55% to 9.59% in female and from 41.17% to 1.83% in male at different stages. The comparative quantities of MYP expression in the gonads of the hybrids were decreased from 37.66% to 19.22% in female and from 36.66% to 12.55% in male at different stages. The results indicated that the difference of MYP expression was correlated with the variation caused by hybridization.
Subject(s)
Egg Proteins/genetics , Gene Expression Regulation, Developmental , Gonads/growth & development , Gonads/metabolism , Strongylocentrotus/growth & development , Strongylocentrotus/genetics , Transcription, Genetic , Animals , Female , Gonads/cytology , Hybridization, Genetic , Male , Polymerase Chain Reaction , RNA, Ribosomal, 18S/biosynthesis , Reference StandardsABSTRACT
Spotted halibut (Verasper variegatus) is the only species of Genus Verasper in China. The fish was naturally distributed in Yellow Sea and Bohai Sea in northern China and Kyushu in Japan and in Korean sea area. Using PCR product direct sequencing, mitochondrial control region sequences of 24 individuals of spotted halibut was confirmed and analyzed. 4 control region haplotypes, resulting from length heteroplamy of the tandem repeat region, was obtained from these 24 fish. Sequence analysis demonstrated that there were four similar structures in the control region, i.e., extended terminal associated sequences (ETAS), central conserved sequence block (CSB), conserved sequence block (CSB), and repeat region, in V. moseri, Limanda ferruginea, Reinhardtius hippoglossoides, Heppoglossoides platessoides, Paralichthys olivaceous, Solea solea, S. senegalensis, and S. lascari. By comparing with other vertebrates, we found that there were similar repeated sequences immediately after the CSB-3 in all of the anuran species.
Subject(s)
DNA, Mitochondrial/genetics , Flounder/genetics , Animals , Base Sequence , DNA, Mitochondrial/chemistry , Flounder/classification , Molecular Sequence Data , Phylogeny , Polymerase Chain Reaction , Sequence Analysis, DNA , Sequence Homology, Nucleic Acid , Tandem Repeat Sequences/geneticsABSTRACT
AFLP analysis of genetic diversity in the three populations of sea urchin Strongylocentrotus intermedius (IN), S. nudus (NU) and F1 progeny (INxNU) was carried out in this paper. In total, 272 loci were amplified with 4 primer pairs, of which 269 were polymorphic and the percentage of polymorphic loci was 98.89%. The Shannon diversity index for S. intermedius, S. nudus, and their hybrid populations was 0.2331+/-0.1273, 0.2005+/-0.1385, and 0.2625+/-0.1067, respectively. The genetic similarity within populations was 0.6876+/-0.0523, 0.6501+/-0.0548, and 0.6552+/-0.0553, respectively. AMOVA analysis indicated that 25.39% of variance was among populations and 74.61% of variance was within populations. This suggested the rich genetic diversity level within populations. Although the hybrids can be classified into two types by apparent characters, they were clustered each other by UPGMA method according to their genetic distances.
