The nucleotide scquence of tRNAphe gene of Carp mitochondria was determined. Sequence comparisons made among Whale,Human,Xenopus laevis, Bovine, Mouse,Chicken and Carp revealed a novel conservative structure in the D....The nucleotide scquence of tRNAphe gene of Carp mitochondria was determined. Sequence comparisons made among Whale,Human,Xenopus laevis, Bovine, Mouse,Chicken and Carp revealed a novel conservative structure in the D. stem (dihydrouridine stem),which is known to vary in other vertebrate mitochondrial and eytoplasmic tRNA genes.This conservative structure contains 13 bp. When the first 7 bp of the conserviative structure were compared with the A domain recognized by RNA Pol III, we noticed partial homology between these two kinds of sequences among different species. In view of the tRNAphe gene's close position to the D loop,it is reasonable to expect extraordinary functions in this novel conservation structure.展开更多
A 605 bp section of mitochondrial 16S rRNA gene from Paralichthys olivaceus, Pseudorhombus cinnamomeus, Psetta maxima and Kareius bicoloratus, which represent 3 families of Order Pleuronectiformes was amplified by PCR...A 605 bp section of mitochondrial 16S rRNA gene from Paralichthys olivaceus, Pseudorhombus cinnamomeus, Psetta maxima and Kareius bicoloratus, which represent 3 families of Order Pleuronectiformes was amplified by PCR and sequenced to show the molecular systematics of Pleuronectiformes for comparison with related gene sequences of other 6 flatfish downloaded from GenBank. Phylogenetic analysis based on ge- netic distance from related gene sequences of 10 flatfish showed that this method was ideal to explore the rela- tionship between species, genera and families. Phylogenetic trees set-up is based on neighbor-joining, maximum parsimony and maximum likelihood methods that accords to the general rule of Pleuronectiformes evolution. But they also resulted in some confusion. Unlike data from morphological characters, P. olivaceus clustered with K. bicoloratus, but P. cinnamomeus did not cluster with P. olivaceus, which is worth further studying.展开更多
The self-incompatibility ( S) loci from the Solanaceae, Rosaceae and Scrophulariaceae encode a class of ribonucleases, known as S RNases, which have been shown to control the pistil expression of self-incompatible rea...The self-incompatibility ( S) loci from the Solanaceae, Rosaceae and Scrophulariaceae encode a class of ribonucleases, known as S RNases, which have been shown to control the pistil expression of self-incompatible reaction. In the former two families, the S loci have been shown to be located near centromere. However, the chromosomal location of the S locus in Antirrhinum, a species of the Scrophulariaceae, is not known. To determine its chromosomal location and genomic organization, an S-2 RNase gene and its corresponding 63 kb BAC clone were separately used for fluorescence in situ hybridization (FISH) of mitotic metaphase chromosomes of a self-incompatible Antirrhinum line Of S2S5. The results showed that the S-2 RNase detected a doublet signal near the centromere of the smallest chromosome (2n = 16). Two separate doublet signals of the tested BAC sequence were shown on both sides of the centromeres of all eight pairs of the chromosomes, suggesting that the Antirrhinum S locus is located in a pericentromeric region. Furthermore, a retrotransposon, named RIS1 (retrotransposon in the S locus), which has not been identified yet in. Antirrhinum, was found next to S-2 RNase. Taken together, the centromeric location of the S locus from the three S-RNase-based self-incompatible families provides a further support on a common origin of their evolution as well as suppressed recombination.展开更多
Sequence variation of partial cytochrome b genes between two Coilia species, C. ectenes and C. mystus, was in- vestigated. Of the 402 nucleotides, twenty-seven (6.72%) are polymorphic and all are synonymous substituti...Sequence variation of partial cytochrome b genes between two Coilia species, C. ectenes and C. mystus, was in- vestigated. Of the 402 nucleotides, twenty-seven (6.72%) are polymorphic and all are synonymous substitutions. At the third positions of genetic condon of cytochrome b gene, the two species show an extreme anti-G bias (<4%) and a pronounced bias towards A and C (>68%). There is no amino acid sequence divergence between the partial cytochrome b genes of the two species, indicating a close genetic relationship between them. The k-2p genetic distance of partial cytochrome b segment of the two species is 0.072, suggesting that the species were separated 3.6 Ma ago, in the middle Pliocene. Our result reveals that the cytochrome b gene is an appropriate marker for studies of population genetic structures and phylogeographic pat- terns of the two species.展开更多
The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids spe...The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phyloge- netic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5’-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were i- dentified at the 5’-end of the sequences. A conserved sequence block, named as CM5’d, was identified in the 5’-end of con- trol region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.展开更多
The integration pattern and adjacent host sequences of the inserted pMThGH-transgene in the F4 hGH-transgeniccommon carp were extensively studied. Here we show that each F4 transgenic fish contained about 200 copies o...The integration pattern and adjacent host sequences of the inserted pMThGH-transgene in the F4 hGH-transgeniccommon carp were extensively studied. Here we show that each F4 transgenic fish contained about 200 copies of thepMThGH-transgene and the transgenes were integrated into the host genome generally with concatemers in a head-to-tail arrangement at 4-5 insertion sites. By using a method of plasmid rescue, four hundred copies of transgenes fromtwo individuals of F4 transgenic fish, A and B, were recovered and clarified into 6 classes. All classes of recoveredtransgenes contained either complete or partial pMThGH sequences. The class I, which comprised 83% and 84.5%respectively of the recovered transgene copies from fish A and B, had maintained the original configuration, indicatingthat most transgenes were faithfully inherited during the four generations of reproduction. The other five classes weredifferent from the original configuration in both molecular weight and restriction map, indicating that a few transgeneshad undergone mutation, rearrangement or deletion during integration and germline transmission. In the five types ofaberrant transgenes, three flanking sequences of the host genome were analyzed. These sequences were common carpβ-actin gene, common carp DNA sequences homologous to mouse phosphoglycerate kinase-1 and human epidermalkeratin 14, respectively.展开更多
The present study investigated conditions for inducing mito-gynogenetic(endomitosis) diploids by hydrostatic pressure in the large yellow croaker Pseudosciaena crocea.In haploid control groups,the development of eggs ...The present study investigated conditions for inducing mito-gynogenetic(endomitosis) diploids by hydrostatic pressure in the large yellow croaker Pseudosciaena crocea.In haploid control groups,the development of eggs was activated with ultraviolet radiated semen.All fry presented typical haploid syndrome in the haploid control groups,and were verified as haploids using cytometry.After hydrostatic pressure treatment,morphologically normal fry reappeared at different frequencies according to the intensity and time of pressure shock.Fry with normal appearance in the pressure treated groups were verified as gynogenetic double haploids(GDHs),containing only one allele from the female parent at all four diagnostic microsatellite loci.For a fixed duration of 3 min,the optimal intensity of blocking the first mitosis was determined to be 40 Mpa,which was similar to that of blocking the second meiosis.There was a "window" of starting time,from 36.1 min to 38.1 min post-insemination at 25.0±1.0°C,within which the production of GDHs was not significantly different.Maximum production of morphologically normal fries,9.36%±2.97% of developed eggs,was found when the eggs were shocked with hydrostatic pressure at 40 Mpa for 3 min,starting from 38.1 min post insemination at 25.0±1.0°C.展开更多
A new method is presented with which we isolated milochondrial DNA from fresh carp liver usingdifferential centrifugation and DNase treatment that gave high yield of purified product with an easyand economical procedu...A new method is presented with which we isolated milochondrial DNA from fresh carp liver usingdifferential centrifugation and DNase treatment that gave high yield of purified product with an easyand economical procedure. Highly distinct bands were displayed in agarose gel electrophoresls ofthe product digested with restrictlon enzymes, which were successfully used in constructingrestriction map and molecular clone of mitochondrial genes. With DNAs thus obtained, we havecloned cysteine tRNA gene (tRNA^(Cys) gene) of carp mitochondria, determined the nucleotide sequenceof it and the light strand origin, and depicted the cloverleaf secondary structure of tDNA^(Cya) and thelight strand origin. Analysis of nucleotide sequences of tRNA^(Cy) genes of 5 vertebrates has revealedunusual features of carp mitochondrial tRNA^(Cy) gene as compared with their cytoplasmic counter-parts, Altogether 36 bases were found in the light strand origin of carp mitochondriaf: 11 pairs in thestem; and 14 bases in the loop. As compared with those of other 11 vertebrate species, the sequenceof the stem is very conservative while both sequence and length of the loop are quite variable. Thestructure of the stem-loop may play an important role in light strand replication.展开更多
Flume experiments and numerical simulation were conducted to characterize the hydrodynamics of a trapezoid artificial reef.Measurements in particle image velocimetry were conducted to observe the formation of upwellin...Flume experiments and numerical simulation were conducted to characterize the hydrodynamics of a trapezoid artificial reef.Measurements in particle image velocimetry were conducted to observe the formation of upwelling and vortices;and forces for the reef model were measured by load cell.The results of flume experiments agree well with the numerical data.In addition,the flow structure around a reef combining trapezoidal and cubic blocks was simulated numerically under two deployment schemes,showing a more complicated flow structure than that of a stand-alone reef.Relationship between drag coefficient and Reynolds number suggest that the degree of turbulence can be assessed from the value of drag coefficient downstream from the reef.The role of the reef in water flow is to reduce flow velocity and generate turbulence.展开更多
Lancelets (subphylum Cephalochordata) are a transitional species between invertebrates and vertebrates. They are currently listed in the Second Order of Protected Animals in China. Lancelets were first documented in t...Lancelets (subphylum Cephalochordata) are a transitional species between invertebrates and vertebrates. They are currently listed in the Second Order of Protected Animals in China. Lancelets were first documented in the waters around the city of Weihai (Shandong, China) in 2002. However, little is known about the phylogeny of this population. We analyzed the sequences of cytochrome b (Cyt b) and cytochrome oxidase c subunit I (CO I) genes from samples collected from coastal waters in the cities of Weihai and Qingdao (~150 km to the south). We analyzed 176 sequences, of which 150 were novel sequences and 26 were obtained from GenBank. Our results suggest that (1) lancelets in the two cities belong to the species Branchiostoma japonicus and have a high level of genetic diversity; (2) there is a high level of gene flow and low level of genetic differentiation between lancelets from the two cities; (3) demographic expansion occurred an estimated 1.1 million years (Ma) ago (mid Pleistocene) for lancelets in Weihai-Qingdao; and (4) the divergence between B. belcheri and B. japonicus was estimated at between 37.75 Ma (early Oligocene)-46.5 Ma (late Eocene).展开更多
Particles,including soot,aerosol and ash,usually exist as fractal aggregates.The radiative properties of the particle fractal aggregates have a great influence on studying the light or heat radiative transfer in the p...Particles,including soot,aerosol and ash,usually exist as fractal aggregates.The radiative properties of the particle fractal aggregates have a great influence on studying the light or heat radiative transfer in the particle medium.In the present work,the performance of the single-layer inversion model and the double-layer inversion model in reconstructing the geometric structure of particle fractal aggregates is studied based on the light reflectancetransmittance measurement method.An improved artificial fish-swarm algorithm(IAFSA)is proposed to solve the inverse problem.The result reveals that the accuracy of double-layer inversion model is more satisfactory as it can provide more uncorrelated information than the single-layer inversion model.Moreover,the developed IAFSA show higher accuracy and better robustness than the original artificial fish swarm algorithm(AFSA)for avoiding local optimization problems effectively.As a whole,the present work supplies a useful kind of measurement technology for predicting geometrical morphology of particle fractal aggregates.展开更多
Nineteen taxa representing 10 genera of Sisoridae were subjected to phylogenetic analyses of sequence data for the nuclear genes Plagl2 and ADNP and the mitochondrial gene cytochrome b. The three data sets were analyz...Nineteen taxa representing 10 genera of Sisoridae were subjected to phylogenetic analyses of sequence data for the nuclear genes Plagl2 and ADNP and the mitochondrial gene cytochrome b. The three data sets were analyzed separately and combined into a single data set to reconstruct phylogenetic relationships among Chinese sisorids. Both Chinese Sisoridae as a whole and the glyptosternoid taxa formed monophyletic groups. The genus Pseudecheneis is likely to be the earliest diverging extant genus among the Chinese Sisoridae. The four Pareuchiloglanis species included in the study formed a monophyletic group. Glaridoglanis was indicated to be earliest diverging glyptosternoid, followed by Glyptosternon maculatum and Exostoma labiatum. Our data supported the conclusion that Oreoglanis and Pseudexostoma both formed a monophyletic group. On the basis of the fossil record and the results of a molecular dating analysis, we estimated that the Sisoridae diverged in the late Miocene about 12.2 Mya. The glyptosternoid clade was indicated to have diverged, also in the late Miocene, about 10.7 Mya, and the more specialized glyptosternoid genera, such as Pareuchiloglanis, originated in the Pleistocene (within 1.9 Mya). The speciation of glyptosternoid fishes is hypothesized to be closely related with the uplift of the Qinghai-Tibet Plateau.展开更多
Fishes that use undulatory locomotion occasionally change their inherent kinematics in terms of some natural behavior.This special locomotion pattern was vividly dubbed "hybrid kinematics" by biologists rece...Fishes that use undulatory locomotion occasionally change their inherent kinematics in terms of some natural behavior.This special locomotion pattern was vividly dubbed "hybrid kinematics" by biologists recently.In this paper,we employed a physical model with body shape of a Mackerel(Scomber scombrus),to use the three most typical undulatory kinematics:anguillform,carangiform and thunniform,to investigate the hydrodynamic performance of the so-called "hybrid kinematics" biological issue.Theoretical models of both kinematics and hydrodynamics of the physical model swimming were developed.Base on this model,the instantaneous force produced by fish undulatory body and flapping tail were calculated separately.We also quantitatively measured the hydrodynamic variables of the robotic model swimming with the three undulatory kinematics on an experimental apparatus.The results of both theoretical model and experiment showed that the robot with thunniform kinematics not only reaches a higher speed but also is more efficient during steady swimming mode.However,anguilliform kinematics won the speed race during the initial acceleration.Additionally,the digital particle image velocimetry(DPIV) results showed some difference of the wake flow generated by the robotic swimmer among the three undulatory kinematics.Our findings may possibly shed light on the motion control of a biomimetic robotic fish and provide certain evidence of why the "hybrid kinematics" exists within the typical undulatory locomotion patterns.展开更多
文摘The nucleotide scquence of tRNAphe gene of Carp mitochondria was determined. Sequence comparisons made among Whale,Human,Xenopus laevis, Bovine, Mouse,Chicken and Carp revealed a novel conservative structure in the D. stem (dihydrouridine stem),which is known to vary in other vertebrate mitochondrial and eytoplasmic tRNA genes.This conservative structure contains 13 bp. When the first 7 bp of the conserviative structure were compared with the A domain recognized by RNA Pol III, we noticed partial homology between these two kinds of sequences among different species. In view of the tRNAphe gene's close position to the D loop,it is reasonable to expect extraordinary functions in this novel conservation structure.
基金Supported by Natural Science Fund of China (No. 30271036) and Natural Science Fund of Shandong Province of China
文摘A 605 bp section of mitochondrial 16S rRNA gene from Paralichthys olivaceus, Pseudorhombus cinnamomeus, Psetta maxima and Kareius bicoloratus, which represent 3 families of Order Pleuronectiformes was amplified by PCR and sequenced to show the molecular systematics of Pleuronectiformes for comparison with related gene sequences of other 6 flatfish downloaded from GenBank. Phylogenetic analysis based on ge- netic distance from related gene sequences of 10 flatfish showed that this method was ideal to explore the rela- tionship between species, genera and families. Phylogenetic trees set-up is based on neighbor-joining, maximum parsimony and maximum likelihood methods that accords to the general rule of Pleuronectiformes evolution. But they also resulted in some confusion. Unlike data from morphological characters, P. olivaceus clustered with K. bicoloratus, but P. cinnamomeus did not cluster with P. olivaceus, which is worth further studying.
文摘The self-incompatibility ( S) loci from the Solanaceae, Rosaceae and Scrophulariaceae encode a class of ribonucleases, known as S RNases, which have been shown to control the pistil expression of self-incompatible reaction. In the former two families, the S loci have been shown to be located near centromere. However, the chromosomal location of the S locus in Antirrhinum, a species of the Scrophulariaceae, is not known. To determine its chromosomal location and genomic organization, an S-2 RNase gene and its corresponding 63 kb BAC clone were separately used for fluorescence in situ hybridization (FISH) of mitotic metaphase chromosomes of a self-incompatible Antirrhinum line Of S2S5. The results showed that the S-2 RNase detected a doublet signal near the centromere of the smallest chromosome (2n = 16). Two separate doublet signals of the tested BAC sequence were shown on both sides of the centromeres of all eight pairs of the chromosomes, suggesting that the Antirrhinum S locus is located in a pericentromeric region. Furthermore, a retrotransposon, named RIS1 (retrotransposon in the S locus), which has not been identified yet in. Antirrhinum, was found next to S-2 RNase. Taken together, the centromeric location of the S locus from the three S-RNase-based self-incompatible families provides a further support on a common origin of their evolution as well as suppressed recombination.
基金the Major State Basic Research Development Program(G19990437).
文摘Sequence variation of partial cytochrome b genes between two Coilia species, C. ectenes and C. mystus, was in- vestigated. Of the 402 nucleotides, twenty-seven (6.72%) are polymorphic and all are synonymous substitutions. At the third positions of genetic condon of cytochrome b gene, the two species show an extreme anti-G bias (<4%) and a pronounced bias towards A and C (>68%). There is no amino acid sequence divergence between the partial cytochrome b genes of the two species, indicating a close genetic relationship between them. The k-2p genetic distance of partial cytochrome b segment of the two species is 0.072, suggesting that the species were separated 3.6 Ma ago, in the middle Pliocene. Our result reveals that the cytochrome b gene is an appropriate marker for studies of population genetic structures and phylogeographic pat- terns of the two species.
基金the Shandong Foundation of Sciences(No.Y2000D04) the National Key Basic Research Program from the Ministry of Science and Technology of China(No.G19990437).
文摘The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phyloge- netic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5’-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were i- dentified at the 5’-end of the sequences. A conserved sequence block, named as CM5’d, was identified in the 5’-end of con- trol region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.
基金supported bythe Major State Basic Research Development Program ofChina (No. 2004CB117406 and G2000016109)the National Natural Science Foundation of China (No.90208024 and 39823003).
文摘The integration pattern and adjacent host sequences of the inserted pMThGH-transgene in the F4 hGH-transgeniccommon carp were extensively studied. Here we show that each F4 transgenic fish contained about 200 copies of thepMThGH-transgene and the transgenes were integrated into the host genome generally with concatemers in a head-to-tail arrangement at 4-5 insertion sites. By using a method of plasmid rescue, four hundred copies of transgenes fromtwo individuals of F4 transgenic fish, A and B, were recovered and clarified into 6 classes. All classes of recoveredtransgenes contained either complete or partial pMThGH sequences. The class I, which comprised 83% and 84.5%respectively of the recovered transgene copies from fish A and B, had maintained the original configuration, indicatingthat most transgenes were faithfully inherited during the four generations of reproduction. The other five classes weredifferent from the original configuration in both molecular weight and restriction map, indicating that a few transgeneshad undergone mutation, rearrangement or deletion during integration and germline transmission. In the five types ofaberrant transgenes, three flanking sequences of the host genome were analyzed. These sequences were common carpβ-actin gene, common carp DNA sequences homologous to mouse phosphoglycerate kinase-1 and human epidermalkeratin 14, respectively.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2006AA10A405)the Foundation for Innovative Research Team of Jimei University(No.2006A001),the Science Foundation of Jimei University(No.ZQ2006037)
文摘The present study investigated conditions for inducing mito-gynogenetic(endomitosis) diploids by hydrostatic pressure in the large yellow croaker Pseudosciaena crocea.In haploid control groups,the development of eggs was activated with ultraviolet radiated semen.All fry presented typical haploid syndrome in the haploid control groups,and were verified as haploids using cytometry.After hydrostatic pressure treatment,morphologically normal fry reappeared at different frequencies according to the intensity and time of pressure shock.Fry with normal appearance in the pressure treated groups were verified as gynogenetic double haploids(GDHs),containing only one allele from the female parent at all four diagnostic microsatellite loci.For a fixed duration of 3 min,the optimal intensity of blocking the first mitosis was determined to be 40 Mpa,which was similar to that of blocking the second meiosis.There was a "window" of starting time,from 36.1 min to 38.1 min post-insemination at 25.0±1.0°C,within which the production of GDHs was not significantly different.Maximum production of morphologically normal fries,9.36%±2.97% of developed eggs,was found when the eggs were shocked with hydrostatic pressure at 40 Mpa for 3 min,starting from 38.1 min post insemination at 25.0±1.0°C.
基金This work was supported by grant from National Foundation of Natural Sciences of China.
文摘A new method is presented with which we isolated milochondrial DNA from fresh carp liver usingdifferential centrifugation and DNase treatment that gave high yield of purified product with an easyand economical procedure. Highly distinct bands were displayed in agarose gel electrophoresls ofthe product digested with restrictlon enzymes, which were successfully used in constructingrestriction map and molecular clone of mitochondrial genes. With DNAs thus obtained, we havecloned cysteine tRNA gene (tRNA^(Cys) gene) of carp mitochondria, determined the nucleotide sequenceof it and the light strand origin, and depicted the cloverleaf secondary structure of tDNA^(Cya) and thelight strand origin. Analysis of nucleotide sequences of tRNA^(Cy) genes of 5 vertebrates has revealedunusual features of carp mitochondrial tRNA^(Cy) gene as compared with their cytoplasmic counter-parts, Altogether 36 bases were found in the light strand origin of carp mitochondriaf: 11 pairs in thestem; and 14 bases in the loop. As compared with those of other 11 vertebrate species, the sequenceof the stem is very conservative while both sequence and length of the loop are quite variable. Thestructure of the stem-loop may play an important role in light strand replication.
基金Supported by the National Natural Science Foundation of China(Nos.31072246,31272703)
文摘Flume experiments and numerical simulation were conducted to characterize the hydrodynamics of a trapezoid artificial reef.Measurements in particle image velocimetry were conducted to observe the formation of upwelling and vortices;and forces for the reef model were measured by load cell.The results of flume experiments agree well with the numerical data.In addition,the flow structure around a reef combining trapezoidal and cubic blocks was simulated numerically under two deployment schemes,showing a more complicated flow structure than that of a stand-alone reef.Relationship between drag coefficient and Reynolds number suggest that the degree of turbulence can be assessed from the value of drag coefficient downstream from the reef.The role of the reef in water flow is to reduce flow velocity and generate turbulence.
基金Supported by the Specialized Research Fund of Third Institute of Oceanography, State Oceanic Administration, China (No. HE09701 (1) and HE09702 (1))the Research Fund of State Oceanic Administration, China (No. HC10301-10, HD10301-10)
文摘Lancelets (subphylum Cephalochordata) are a transitional species between invertebrates and vertebrates. They are currently listed in the Second Order of Protected Animals in China. Lancelets were first documented in the waters around the city of Weihai (Shandong, China) in 2002. However, little is known about the phylogeny of this population. We analyzed the sequences of cytochrome b (Cyt b) and cytochrome oxidase c subunit I (CO I) genes from samples collected from coastal waters in the cities of Weihai and Qingdao (~150 km to the south). We analyzed 176 sequences, of which 150 were novel sequences and 26 were obtained from GenBank. Our results suggest that (1) lancelets in the two cities belong to the species Branchiostoma japonicus and have a high level of genetic diversity; (2) there is a high level of gene flow and low level of genetic differentiation between lancelets from the two cities; (3) demographic expansion occurred an estimated 1.1 million years (Ma) ago (mid Pleistocene) for lancelets in Weihai-Qingdao; and (4) the divergence between B. belcheri and B. japonicus was estimated at between 37.75 Ma (early Oligocene)-46.5 Ma (late Eocene).
基金supported by the National Natural Science Foundation of China(No.51806103)the Natural Science Foundation of Jiangsu Province(No.BK20170800)Aeronautical Science Foundation of China(No.201928052002)。
文摘Particles,including soot,aerosol and ash,usually exist as fractal aggregates.The radiative properties of the particle fractal aggregates have a great influence on studying the light or heat radiative transfer in the particle medium.In the present work,the performance of the single-layer inversion model and the double-layer inversion model in reconstructing the geometric structure of particle fractal aggregates is studied based on the light reflectancetransmittance measurement method.An improved artificial fish-swarm algorithm(IAFSA)is proposed to solve the inverse problem.The result reveals that the accuracy of double-layer inversion model is more satisfactory as it can provide more uncorrelated information than the single-layer inversion model.Moreover,the developed IAFSA show higher accuracy and better robustness than the original artificial fish swarm algorithm(AFSA)for avoiding local optimization problems effectively.As a whole,the present work supplies a useful kind of measurement technology for predicting geometrical morphology of particle fractal aggregates.
基金supported by the National Natural Science Foundation of China (Grant No. 31090254)
文摘Nineteen taxa representing 10 genera of Sisoridae were subjected to phylogenetic analyses of sequence data for the nuclear genes Plagl2 and ADNP and the mitochondrial gene cytochrome b. The three data sets were analyzed separately and combined into a single data set to reconstruct phylogenetic relationships among Chinese sisorids. Both Chinese Sisoridae as a whole and the glyptosternoid taxa formed monophyletic groups. The genus Pseudecheneis is likely to be the earliest diverging extant genus among the Chinese Sisoridae. The four Pareuchiloglanis species included in the study formed a monophyletic group. Glaridoglanis was indicated to be earliest diverging glyptosternoid, followed by Glyptosternon maculatum and Exostoma labiatum. Our data supported the conclusion that Oreoglanis and Pseudexostoma both formed a monophyletic group. On the basis of the fossil record and the results of a molecular dating analysis, we estimated that the Sisoridae diverged in the late Miocene about 12.2 Mya. The glyptosternoid clade was indicated to have diverged, also in the late Miocene, about 10.7 Mya, and the more specialized glyptosternoid genera, such as Pareuchiloglanis, originated in the Pleistocene (within 1.9 Mya). The speciation of glyptosternoid fishes is hypothesized to be closely related with the uplift of the Qinghai-Tibet Plateau.
基金supported by the National Natural Science Foundation of China (Grant No. 61075100)
文摘Fishes that use undulatory locomotion occasionally change their inherent kinematics in terms of some natural behavior.This special locomotion pattern was vividly dubbed "hybrid kinematics" by biologists recently.In this paper,we employed a physical model with body shape of a Mackerel(Scomber scombrus),to use the three most typical undulatory kinematics:anguillform,carangiform and thunniform,to investigate the hydrodynamic performance of the so-called "hybrid kinematics" biological issue.Theoretical models of both kinematics and hydrodynamics of the physical model swimming were developed.Base on this model,the instantaneous force produced by fish undulatory body and flapping tail were calculated separately.We also quantitatively measured the hydrodynamic variables of the robotic model swimming with the three undulatory kinematics on an experimental apparatus.The results of both theoretical model and experiment showed that the robot with thunniform kinematics not only reaches a higher speed but also is more efficient during steady swimming mode.However,anguilliform kinematics won the speed race during the initial acceleration.Additionally,the digital particle image velocimetry(DPIV) results showed some difference of the wake flow generated by the robotic swimmer among the three undulatory kinematics.Our findings may possibly shed light on the motion control of a biomimetic robotic fish and provide certain evidence of why the "hybrid kinematics" exists within the typical undulatory locomotion patterns.