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Rotifers are natural initial bait for fish larvae in freshwater. Here, the effects of various concentrations of acidified eggshell powder solutions (0, 20, 40, 80, 160, and 320 mg/L) on the growth and reproduction of the rotifer Brachionus calyciflorus were evaluated in culture experiments (11 days). The population density, catalase (CAT) and superoxide dismutase (SOD) activity, and Na and Mg contents in rotifers were significantly higher in the 20–160 mg/L groups than in the control group. A redundancy analysis showed that the Na, Mg, Cr, K, and Ca contents were positively correlated with the rotifer population density and CAT and SOD activity. Furthermore, the generation time and lifespan of F2 rotifers were significantly higher in the 20–40 mg/L treatment groups (82.0 ± 3.7 hr and 162.0 ± 2.7 hr, respectively) than in the control group (64.0 ± 4.0 hr and 128.0 ± 4.0 hr, respectively). Average egg production in F2 rotifers was significantly higher in the 20–80 mg/L treatment groups (15.2 ± 0.7 individuals) than in the control group (11.7 ± 1.2 individuals). These results indicate that 20 mg/L eggshell powder is optimal for growth and reproduction in B. calyciflorus, providing a theoretical basis for using new mineral sources in high-quality open bait for fish larvae.

Global climate changes are affecting organisms and their interactions in terrestrial and aquatic ecosystems, such as the increase in temperature and CO2 concentration. Herbivory interaction is a very important part of nutrient cycle and energy flow in freshwater ecosystem, and climate changes may directly or indirectly affect aquatic plants, aquatic herbivores and their interactions. In this study, we explored the effects of the rising temperature, elevated CO2 concentrations and herbivory by an herbivorous snail (Radix auricularia L.) on a submerged plant (Vallisneria natans L.). Our results showed that herbivory, temperature, and CO2 had specific effects on snail and plant growth, statistically there was only one interaction-a reduction in leaf number. Under different experimental conditions, snail herbivory always has negative effects on biomass accumulation and growth of V. natans. Moreover, the increases in temperature also inhibited its growth. Snail herbivory reduced the content of total carbon and total nitrogen of V. natans in all treatments, while the total phenols content increased. Our findings indicate that the rising temperature, elevated CO2 concentrations and herbivory have interactive effects on the growth and stoichiometry of submerged macrophytes, but further research is needed between aquatic plants and aquatic herbivores to aid prediction the impact of climate change on freshwater ecosystems. [ABSTRACT FROM AUTHOR]

To efficiently remove nitrogen from the biofiltration system, the effect of different electron donors and C/N (dissolved organic carbon [DOC]/nitrate) on dissimilatory nitrate reduction to ammonium (DNRA), and denitrification was studied. Electron donor addition significantly increased the gene abundance (nirS and nrfA) and denitrification rate, resulting in higher NO3−-N removal efficiency (over 70%) in refractory organic carbon (bagasse and rice straw) groups. Easily degradable organic carbon (sucrose) caused rapid DOC accumulation, fueling the DNRA process, and NH4+-N accumulation. Inorganic electron donors (ferrous sulfate and sodium sulfide) were unsuitable due to poor denitrification gene abundance, low rate, as well as low NO3−-N removal efficiency. The decrease in C/N was beneficial to denitrification but restricted the occurrence of DNRA, finally reducing N retention capacity. Therefore, the regulation of C/N can play a significant contributory role in the switching of denitrification and DNRA process. [ABSTRACT FROM AUTHOR]

Macroinvertebrates have been recognized as key ecological indicators of aquatic environment and are the most commonly used approaches for water quality assessment. However, species identification of macroinvertebrates (especially of aquatic insects) proves to be very difficult due to the lack of taxonomic expertise in some regions and can become time‐consuming. In this study, we evaluated the feasibility of DNA barcoding for the classification of benthic macroinvertebrates and investigated the genetic differentiation in seven orders (Insecta: Ephemeroptera, Plecoptera, Trichoptera, Diptera, Hemiptera, Coleoptera, and Odonata) from four large transboundary rivers of northwest China and further explored its potential application to biodiversity assessment. A total of 1,144 COI sequences, belonging to 176 species, 112 genera, and 53 families were obtained and analyzed. The barcoding gap analysis showed that COI gene fragment yielded significant intra‐ and interspecific divergences and obvious barcoding gaps. NJ phylogenetic trees showed that all species group into monophyletic species clusters whether from the same population or not, except two species (Polypedilum. laetum and Polypedilum. bullum). The distance‐based (ABGD) and tree‐based (PTP and MPTP) methods were utilized for grouping specimens into Operational Taxonomic Units (OTUs) and delimiting species. The ABGD, PTP, and MPTP analysis were divided into 177 (p =.0599), 197, and 195 OTUs, respectively. The BIN analysis generated 186 different BINs. Overall, our study showed that DNA barcoding offers an effective framework for macroinvertebrate species identification and sheds new light on the biodiversity assessment of local macroinvertebrates. Also, the construction of DNA barcode reference library of benthic macroinvertebrates in Eurasian transboundary rivers provides a solid backup for bioassessment studies of freshwater habitats using modern high‐throughput technologies in the near future. [ABSTRACT FROM AUTHOR]

In the present study, to assess the immunotoxicity of cypermethrin (CYP) in fish, Chinese rare minnows (Gobiocypris rarus) were exposed to environmentally relevant concentrations (0.15, 0.5, and 1.5 μg/L) of CYP for 28 d and subjected to pathogen challenge trials for 2 d. After 28 d of CYP exposure, the levels of Immunoglobulin M (IgM), Alkaline phosphatase (ALP), and C-reactive protein (CRP) were significantly decreased (p < 0.05) after treatment with 1.5 μg/L CYP. Moreover, an induction of inflammatory cytokine transcripts (tnfa , il-6 , il-8 , and il-12) was observed (p < 0.05) after treatment with 1.5 μg/L CYP. After challenge with Pseudomonas fluorescens (P. fluorescens) , plasma lysozyme (LYS) activity at 24 and 48 hours post-injection (hpi) was significantly decreased in the 0.5 and 1.5 μg/L CYP treatment groups (p < 0.05). Moreover, liver Complement component 3 (C3) and CRP contents at 24 hpi were significantly decreased in the 1.5 μg/L CYP treatment group (p < 0.05), whereas significant decreases in liver C3 and IgM contents were observed at 48 hpi (p < 0.05). Inhibition of expression of Toll-like receptor-nuclear factor kappa B (TLR-NF-kB) signaling pathway-related genes was observed in the CYP treatment groups and resulted in significant down-regulation of inflammatory cytokines (il-1β and il-12) in the 1.5 μg/L CYP treatment group at 48 hpi (p < 0.05). Interestingly, the mortality in the 0.5 and 1.5 μg/L CYP treatments was significantly increased at 48 hpi (p < 0.05). These results indicated that environmentally relevant concentrations of CYP suppressed the Chinese rare minnow immune system and reduced immune defense against bacterial infection, thereby causing subsequent mortality. Meanwhile, our results demonstrated that a subsequent host resistance challenge is an effective method for determining the immunotoxicity of chemicals (e.g., CYP). Image 1 • CYP induced immune dysfunction in rare minnows at environmentally relevant concentrations. • Reduction in immune molecules revealed an immunosuppression in fish following CYP exposure. • Disturbs in TLR-NF-kB signaling pathway was induced by CYP. • The sensitivity of fish to P. fluorescens was increased following CYP exposure. CYP induced immunotoxicity, suppressed the immunity of Chinese rare minnows, which rendered them vulnerable to pathogens and caused death. [ABSTRACT FROM AUTHOR]

Aquatic plants and associated herbivores are expected to perform better under the rising atmospheric CO2 concentration brought about by climate change. However, it is not clear how increasing CO2 affects herbivory on aquatic macrophytes. In this research, we set four treatments (A group: ambient air without snails; AS group: ambient air with snails; E group: elevated CO2 without snails; and ES group: elevated CO2 with snails) and studied the effects of low (0-0.5 mg/L) and high (4-8 mg/L) CO2 concentration on the growth, morphology, and chemical traits of the macrophyte Vallisneria spiralis (Angiosperms: Hydrocharitaceae) and the snail Radix auricularia (Pulmonata: Lymnaeidae), and the relationships between them in the laboratory. We found that herbivory decreased the total biomass of V. spiralis by 28.6% and 25.3% under low and high CO2 conditions, respectively. Compared with A group, ES group reduced the total plant biomass by 43.3%. Elevated CO2 and herbivory both affected the growth of V. spiralis and change its resource allocation patterns. Total nitrogen content in V. spiralis leaves decreased under herbivory condition, and total phenols increased under the interactions condition between elevated CO2 and herbivory. However, total C content of R. auricularia increased under elevated CO2 condition. These results could provide valuable insights into how climate change affects plant-herbivore interactions and food web structure in shallow inland waters. [ABSTRACT FROM AUTHOR]

Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) is considered a re-emerging environmental pollutant, and exposure to environmentally relevant concentrations has been shown to cause individual developmental toxicity in zebrafish and the water flea ( Daphnia magna ). However, multigenerational effects during exposure to TDCIPP and after subsequent recovery were unknown. In the present study, individuals of a model aquatic organism, the ciliated protozoan, T. thermophila were exposed to environmentally-relevant concentrations of TDCIPP (0, 300 or 3000 ng/L) for 60 days (e.g., theoretically 372 generations) followed by a 60-day period of recovery, during which T. thermophila were not exposed to TDCIPP. During exposure and after exposure, effects at the molecular, histological, individual and population levels were examined. Multigenerational exposure to 300 or 3000 ng TDCIPP/L for 60 days significantly decreased numbers of individuals, sizes of individuals, expressed as length and width of bodies, number of cilia, and depth and diameter of basal bodies of cilia, and up-regulated expressions of genes related to assembly and maintenance of cilia. Complete or partial recoveries of theoretical sizes of populations as well as sizes of individuals and expressions of genes were observed during the 60-day recovery period. Effects on number of cilia and depth and diameter of basal body of cilia were not reversible and could still be observed long after cease of TDCIPP exposure. Collectedly, and shown for the first time, multigenerational effects to T. thermophila were caused by exposure to environmentally relevant concentrations of TDCIPP. Also, there were multi-generational effects at the population level that were not caused by carry-over exposure to TDCIPP. The “permanent” alterations and their potential significance are discussed. [ABSTRACT FROM AUTHOR]

ELL associated factor 1 and ELL associated factor 2 (EAF1/2 factors) are reported to play important roles in tumor suppression and embryogenesis. Our previous studies showed that eaf factors mediated effective convergence and extension (C&E) movements and modulated mesoderm and neural patterning by regulating both non-canonical and canonical Wnt signaling in the early embryonic process. In this study, through knockdown of both eaf1 and eaf2 in embryos, we found that differentiation of primary erythroid cells was blocked, but hematopoietic precursor cells maintained in eafs morphants. Co-injection of c-myb-MO rescued the erythroid differentiation in eafs morphants, as indicated by the restored expression of the erythroid-specific gene, βe3 globin. In addition, low dosage of c-myb effectively blocked the βe3 globin expression in embryos, and did not affect the expression of markers of hematopoietic progenitor cells and other mesoderm, which was similar to the phenotypes we observed in eafs morphants. We also revealed that knockdown Wnt signaling by transiently inducing dn-Tcf in embryos at the bud stage down-regulated the increased c-myb to normal level and also restored βe3 globin expression in eafs morphants. Our evidence points to a novel role for eaf factors in controlling erythroid cell fate by regulating c-Myb expression through canonic Wnt signaling. [ABSTRACT FROM AUTHOR]

Based upon the morphological characters, the genusTriplophysa(plateau Loach) is a highly diverse group in the family Balitoridae (or Cypriniformes, Cobitoidea) with 133 valid species. Therefore, the taxonomic relationship of this species at the genetic level remains ambiguous. In the present study, we sequenced the complete mitochondrial genome ofTriplophysa dorsalis. In order to understand its position and genetic background at the gene level, the characteristics of mitochondrial DNA sequences and phylogenetic relationship were examined. The mitochondrial genome ofT. dorsalisis similar to those of the typical vertebrates, 16 572 bp in length, including 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a non-coding control region (D-loop). All genes were encoded on the heavy strand except forND6and 8 tRNA genes. The overall base composition of the heavy strand was 28.16%, 28.41%, 25.62% and 17.82% for A, T, C and G, respectively. Phylogenetic analyses showed that the sevenTriplophysaspecies clustered together withT. dorsalisto form a sister group withTriplophysa strauchii, T. bleekeri, T. stoliczkaiandT. bombifrons. The two generaTriplophysaandBarbatulaformed a sister-group relationship, the speciesHomatula potaninilocated in the intermediate position, and the genusLeptobotia elongatawas in the basal position in the subfamily Nemacheilidae. Further investigations with moreTriplophysaspecies need to be performed for better understanding of the evolutionary history of this fascinating genus. [ABSTRACT FROM AUTHOR]

The complete nucleotide sequence of the mitochondrial genome ofLucioperca luciopercawas cloned and sequenced in this study, which contained 16,542 bp. Results showed that the sequence was made up of 13 proteins, 22 transfer RNAs and 2 ribosomal RNA genes. The control region and the origin of the light strand replication were similar to other vertebrates. All protein-coding genes began with ATG except forCOX1andCOX2, theCOX1genes started with ATC andCOX2genes started with ATT, while all of those ended with TAA, TA, T or TAG. The result could be used in related studies such as molecular ecology and evolutionary biology. [ABSTRACT FROM AUTHOR]

In the present work, the complete mitochondrial genome of theTriplophysa strauchii(Cypriniformes: Cyprinidae, Balitoridae, Cobitoidea) is sequenced and placed, the phylogenetic analysis with another individual ofTriplophysafishes was carried out. The mitogenome is 16,590 bp in length, consisting 13 protein genes, 22 tRNA genes, 2 rRNA genes, and 2 non-coding regions. The total base composition is 28.26%, 28.49%, 25.42% and 17.82% for A, T, C and G, respectively. All genes were encoded on the heavy strand except for ND6 and 8 tRNA genes. These results will provide useful data for species identification and genetic study ofTriplophysafishes. [ABSTRACT FROM AUTHOR]

In this study, the complete sequence of the 16,527 base pairsCottus sibiricus altaicusmitochondrial genome was presented. The composition of the whole mitochondrial DNA was 26.93% for A, 26.30% for T, 29.70% for C, 17.07% for G. The genes found inC. sibiricus altaicusand other vertebrate mtDNA were the same, which contained the genes for 13 proteins, 22 transfer RNAs, 2 ribosomal RNAs and 2 main non-coding genes (the control region (CR) and the origin of the light strand replication (OL). The sequence showed high economy of organization in that there were few nucleotides between individual genes except for the control region. [ABSTRACT FROM AUTHOR]

As reported, previous studies ofPhoxinus phoxinus ujmonensis(Cypriniformes: Cyprinidae) have focused primarily on morphology and ecology. In this study, we cloned and sequenced the complete nucleotide sequence of the mitochondrial genome forP. phoxinus ujmonensis. The mitogenome was 17,738 bp in length, including 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and 1 control region. All genes were encoded on the heavy strain except for ND6 and eight tRNA genes. The overall base composition of the heavy strain was 28.50% for A, 28.24% for T, 25.32% for C and 17.94% for G. The control region was revealed to contain tandem repeats. The mitogenome data ofP. phoxinus ujmonensisshould contribute to phylogenetic analysis and studies of population genetics ofPhoxinusfishes. [ABSTRACT FROM AUTHOR]

In this study, we determined the complete nucleotide sequence of the mitochondrial genome for a cold water fish,Leuciscus idus. The complete mitochondrial genome was sequenced and analyzed using the primer walking method and 30 pairs of newly designed primers were used. Direct sequencing of the PCR products demonstrated that the genome contained the same 37 mitochondrial genes (two ribosomal RNA, 22 transfer RNA and 13 protein-coding genes) and two main non-coding regions (the control region and the origin of the light strand replication) as those found in other vertebrates. Nearly all the protein-coding genes’ start codons were ATG exceptCOX 1, meanwhile, the termination codons of which varied with TAA, TA, T, or TAG. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome ofLeuciscus leuciscus baicalensiswas cloned and sequenced in the present study. The genome which had a mostly conserved structural organization in comparison with that of other teleost fish was 16,606 bp in size. It consisted of 37 genes (13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes), and 2 main non-coding regions (the control region and the origin of the light strand replication). All protein-coding genes started with ATG except forCOX 1, which began with GTG. However, the termination codons of 13 protein-coding genes varied with TAA, TA, T or TAG. The complete mitochondrial genome sequence provided useful information for phylogenetic analysis and studies of population genetics ofL. leuciscus baicalensis. [ABSTRACT FROM PUBLISHER]

In this study, we cloned and sequenced the complete mitochondrial genome ofBarbatula nuda. The genome was found to be 16,619 bp in size with a mostly conserved structural organization when compared with that of other teleost fish. It contained 37 genes (13 protein-coding genes, 22 transfer RNA genes, and 2 ribosomal RNA genes) and 2 main non-coding regions (the control region and the origin of the light-strand replication). All protein-coding genes are initiated with ATG except forCOX 1, which begin with GTG instead. However, the termination codons of 13 protein-coding genes varied with TAA, TA, T or TAG. The complete mitochondrial genome sequence is useful for phylogenetic analysis and studies of population genetics ofB. nuda. [ABSTRACT FROM PUBLISHER]

Abstract: A full sequence of TaHSP70 (heat shock protein 70 of Tanichthys albonubes) was amplified which was 2398bp, including an open reading frame (ORF) of 1392bp encoding a polypeptide of 643 amino acids with all three HSP70 family signatures and cytosolic motif of EEVD. Genomic DNA structure analysis revealed that the TaHSP70 gene contained one intron in 5′UTR. BLAST analysis revealed that the TaHSP70 gene shared high similarity with other known HSP70 genes. The alignment of inferred amino acid sequences also showed high degrees of similarity among the homologues. There was a basal mRNA expression of TaHSP70 in the different tissues from the non-exposed T. albonubes and the highest expression level in the liver. To investigated the time- and dose-dependent relationship of the expression of TaHSP70 following exposure to heavy metals, T. albonubes were exposed to 2−1 96h-LC50 (0.027mgL−1), 4−1 96h-LC50 (0.0135mgL−1) of copper and 2−1 96h-LC50 (2.31mgL−1), 4−1 96h-LC50 (1.15mgL−1) of cadmium for 96h. Hsp70 expression relative to the control was analyzed by Quantitative real-time PCR and Western blotting. The results indicated that there were a dose-dependent expression pattern and an exposure time effect in the liver responded to heavy metal stress. Interestingly, TaHSP70 gene expressions did not show consistent changes between transcription and translation levels. Taken together, the dynamics of TaHSP70 expression observed provided important insight into heavy metal stress, heat shock protein activity, and the potential ways to monitor the chronic stressors in T. albonubes culture environments. [Copyright &y& Elsevier]

Our study aimed to investigate the effect of dietary Astragalus polysaccharide (APS) on growth performance, gut and liver health and anti-viral capability of zebrafish. Zebrafish were fed control diet and the experimental diets containing 0.01% or 0.02% APS for three weeks. Growth performance, gut health parameters such as expression of inflammatory and tight junction genes, antioxidant capability, and microbiota composition were detected after three weeks feeding. Liver health was evaluated by serum ALT and AST levels, as well as expression of genes realated to inflammation and lipid metabolism. Zebrafish were challenged by SVCV at the end of feeding. The antiviral immune response was evaluated at 4 days post SVCV infection and survival rate was calculated 14 days after challenge. The results showed that 0.01% and 0.02% APS supplementation increased weight gain and decreased the FCR of zebrafish (P < 0.05). The intestinal expression of anti-inflammatory cytokine IL-10, tight junction protein 1b, and Occludin1 was significantly up-regulated in 0.01% APS group compared with control (P < 0.05). Furthermore, 0.01% APS decreased the content of MDA and increased total antioxidant capacity in zebrafish intestine, and the relative expression of SOD, GST and Gpxa were improved. Total bacteria and the abundance of Fusobacteria and Firmicutes in the intestinal microbiota was increased in 0.01% and 0.02% APS groups compared with control (P < 0.05). Zebrafish fed 0.01% APS showed higher survival rate after SVCV challenge. Accordingly, the expression of antiviral genes in the spleen was increased at 4 days post infection. In contrast to 0.01% supplementation, 0.02% APS compromised liver health, and exerted no positive effects on antiviral immunity. In conclusion, our results indicate that dietary 0.01% APS supplementation can improve growth performance, gut health and antiviral immunity of zebrafish, while 0.02% APS compromised liver health. • 0.01% and 0.02% APS supplementation increased weight gain and decreased FCR of zebrafish. • Dietary 0.02% APS compromised liver health of zebrafish in comparison to control. • 0.01% APS enhanced the antiviral immunity of zebrafish. [ABSTRACT FROM AUTHOR]

In this study, to assess the immunotoxicity of deltamethrin on fish, adult Chinese rare minnows (Gobiocypris rarus) were exposed to 0.1, 0.3, and 1 μg/L deltamethrin for 28 d. Many immunological parameters and histopathological alterations were determined. The results showed that lymphocyte number was markedly decreased at 0.3 and 1 μg/L treatments, whereas the neutrophil number was strongly increased at 1 μg/L treatments (p < 0.05). Furthermore, lysozyme (LYS), immunoglobulin M (IgM), and complement component 3 (C3) levels at 0.3 and 1 μg/L treatments were markedly reduced, whereas alkaline phosphatase (ALP) activity were marked increased at 1 μg/L treatments (p < 0.05). The transcripts of almost all TLR (Toll-like receptor) signaling pathway-related genes were up-regulated. Histological lesions in the livers, intestines, and gills were observed at all treatments. Then, all remaining fish from controls and deltamethrin-exposed groups were injected with Pseudomonas fluorescens (P. fluorescens) for 48 h. At 24 and 48 h post-injection with P. fluorescens (hpi), the lymphocyte numbers were strongly reduced at 0.3 and 1 μg/L deltamethrin-exposed groups, whereas LYS and C3 levels were strongly reduced at 0.3 and 1 μg/L deltamethrin-exposed groups (p < 0.05). Obvious reduces in IgM levels were also detected at 0.3 and 1 μg/L deltamethrin-exposed groups at 48 hpi (p < 0.05). The transcripts of almost all TLR signaling pathway-related genes were significantly down-regulated, whereas the levels of related microRNAs (miRNAs) were markedly increased at all deltamethrin-exposed groups at 24 and 48 hpi. Moreover, the bacterial load in the liver and the mortality of fish were significantly increased at 1 μg/L deltamethrin-exposed groups at 24 and 48 hpi (p < 0.05). Furthermore, obvious histological damage in the livers, intestines, and gills were observed at all deltamethrin-exposed fish at 48 hpi. Overall, our results demonstrated that environmentally relevant concentration deltamethrin suppressed immunity and rendered the fish vulnerable to P. fluorescens infection, subsequently inducing mortality. Unlabelled Image • Deltamethrin induced immunotoxicity in Chinese rare minnow at environmentally relevant concentrations. • Deltamethrin caused histopathological damage to liver, intestine, and gill of Chinese rare minnows. • Deltamethrin exposure destroyed fish immune system and induced fish immunosuppression. • Deltamethrin exposure rendered fish vulnerable to P. fluorescens infection. [ABSTRACT FROM AUTHOR]

Background: Molecular adaptation to the severe environments present during the uplift of the Qinghai-Tibet Plateau has attracted the attention of researchers. The divergence of the three specialization groups of schizothoracins (Primitive, Specialized and Highly Specialized) may correspond to the three phases of plateau uplift. Based on the transcripts of representative species of the three specialized groups and an outgroup, genes in schizothoracins that may have played important roles during the adaptation to new environments were investigated., Results: The contigs of Gymnodiptychus dybowskii and Schizothorax pseudaksaiensis were compared with those of Gymnocypris przewalskii ganzihonensis and the outgroup Sinocyclocheilus angustiporus, and 5,894 ortholog groups with an alignment length longer than 90 nt after deleting gaps were retained. Evolutionary analyses indicated that the average evolutionary rate of the branch leading to the Specialized group was faster than that of the branch leading to the Highly Specialized group. Moreover, the numbers of gene categories in which more than half of the genes evolved faster than the average values of the genome were 117 and 15 along the branches leading to the Specialized and Highly Specialized groups, respectively. A total of 40, 36, and 55 genes were likely subject to positive selection along the branches leading to the Primitive, Specialized and Highly Specialized groups, respectively, and many of these genes are likely relevant to adaptation to the cold temperatures, low oxygen concentrations, and strong ultraviolet radiation that result from elevation., Conclusions: By selecting representative species of the three groups of schizothoracins and applying next-generation sequencing technology, several candidate genes corresponding to adaptation to the three phases of plateau uplift were identified. Some of the genes identified in this report that were likely subject to positive selection are good candidates for subsequent evolutionary and functional analyses of adaptation to high altitude.

As reported, previous studies of Phoxinus phoxinus ujmonensis (Cypriniformes: Cyprinidae) have focused primarily on morphology and ecology. In this study, we cloned and sequenced the complete nucleotide sequence of the mitochondrial genome for P. phoxinus ujmonensis. The mitogenome was 17,738 bp in length, including 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and 1 control region. All genes were encoded on the heavy strain except for ND6 and eight tRNA genes. The overall base composition of the heavy strain was 28.50% for A, 28.24% for T, 25.32% for C and 17.94% for G. The control region was revealed to contain tandem repeats. The mitogenome data of P. phoxinus ujmonensis should contribute to phylogenetic analysis and studies of population genetics of Phoxinus fishes.

In this study, we determined the complete nucleotide sequence of the mitochondrial genome for a cold water fish, Leuciscus idus. The complete mitochondrial genome was sequenced and analyzed using the primer walking method and 30 pairs of newly designed primers were used. Direct sequencing of the PCR products demonstrated that the genome contained the same 37 mitochondrial genes (two ribosomal RNA, 22 transfer RNA and 13 protein-coding genes) and two main non-coding regions (the control region and the origin of the light strand replication) as those found in other vertebrates. Nearly all the protein-coding genes' start codons were ATG except COX 1, meanwhile, the termination codons of which varied with TAA, TA, T, or TAG.

In this study, the complete sequence of the 16,527 base pairs Cottus sibiricus altaicus mitochondrial genome was presented. The composition of the whole mitochondrial DNA was 26.93% for A, 26.30% for T, 29.70% for C, 17.07% for G. The genes found in C. sibiricus altaicus and other vertebrate mtDNA were the same, which contained the genes for 13 proteins, 22 transfer RNAs, 2 ribosomal RNAs and 2 main non-coding genes (the control region (CR) and the origin of the light strand replication (O(L)). The sequence showed high economy of organization in that there were few nucleotides between individual genes except for the control region.

Bioconcentrations of tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) in brain, gonad, and liver as well as effects on fecundity and development of zebrafish (Danio rerio) were determined. Zebrafish (1-month old) were exposed to environmentally relevant concentrations of 29 ± 2.1, 600 ± 21, or 6300 ± 130 ng TDCIPP/L. After 120 days of exposure, TDCIPP accumulated in the brain, gonad, and liver with bioconcentration factors of 460, 38, and 87 in females and 26, 55, and 110 in males, respectively. TDCIPP accumulated to a greater extent in brains of females than those of males. Exposure to 6300 ± 130 ng TDCIPP/L resulted in significantly (P < 0.05) fewer eggs being produced, but the histology of the gonad, plasma concentrations of estradiol and 11-ketotestosterone, and expression of genes involved in hypothalamic-pituitary-gonadal-liver axis were not significantly (P > 0.05) different between individuals exposed to TDCIPP and the unexposed control fish. Exposure to TDCIPP resulted in shorter body length, lighter body mass, and lower gonadal-somatic index in females. These effects were possibly due to down-regulation of expression of genes along the growth hormone/insulin-like growth factor (GH/IGF) axis. Correlations between the production of eggs and developmental parameters or expression of genes along the GH/IGF axis further suggested that environmentally relevant concentrations of TDCIPP could have adverse effects on reproduction, possibly due to the inhibition of the growth of females.

The identification of genes that may be responsible for the divergence of closely related species is one of the central goals of evolutionary biology. The species of endemic East Asian Cyprinidae diverged less than 8millionyears ago, and the morphological differences among these species are great. However, the genetic basis of their divergence remains unknown. In this report, we investigated the transcriptome of one endemic East Asian cyprinid - the yellow-cheek carp Elopichthys bambusa. A comparison with the publicly available transcriptomes of other endemic East Asian cyprinids, including the silver carp (Hypophthalmichthys molitrix) and blunt-nose black bream (Megalobrama amblycephala), revealed a number of candidate adaptive genes in each species, such as zona pellucida glycoprotein 2 in E. bambusa and zebrafish vitelline envelope protein in M. amblycephala. An enrichment test showed the enrichment of some specific gene ontology (GO) terms for these putatively adaptive genes. Taken together, our work is the first step toward elucidating the genes that may be related to the divergence of endemic East Asian Cyprinidae, and these genes identified as being probably under positive selection should be good candidates for subsequent evolutionary and functional studies., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: Sturgeon cultivation is important for both industry and aquaculture in China. To date, more than 17 species or strains have been farmed for fillets and caviar production. Crossbreeding among different sturgeon species is frequent and the F2 hybrids are fertile. However, large-scale farming can have negative impacts on wild populations i.e. escape of exotic sturgeons and must be taken into consideration. Escape of exotic sturgeons can cause severe ecological problems, including threatening native sturgeon species once the exotic varieties become established or hybridize with native individuals. However, little is known about their genetic resources and variation., Methods: Genetic diversity and introgression of seven sturgeon species were analyzed using mitochondrial DNA cytochrome oxidase subunit I (COI) and nine microsatellite markers. This study included 189 individuals from seven sturgeon species and 277 individuals from ten lineages of F2 hybrid strains., Results: MtDNA COI sequences (632 bp long) were generated from 91 individuals across the 17 sturgeon strains and produced 23 different haplotypes. Haplotype diversity was high (h = 0.915 ± 0.015) and nucleotide diversity was low (π = 0.03680 ± 0.00153) in the seven sturgeon species and ten interspecific hybrids. Phylogenetic analyses resulted in almost identical tree topologies, and different haplotype structures were mainly related with sturgeons of different female parents. Analysis of molecular variance revealed that 81.73% of the genetic variance was due to matrilineal differences, while 9.40% resulted from strain variation. Pairwise Fst values obtained with POLYSAT software, were high among strains and ranged from 0.031 to 0.164. Admixture analysis assigned seven distinct groups and ten genotypes of admixed clusters composed of hybrid strains using STRUCTURE when assuming K = 7., Conclusions: The interspecific mtDNA gene tree corresponded to the expected taxonomic divisions. These relationships were also supported by the results from the microsatellite analysis and contributed to unambiguously identify seven sturgeon species and ten F2 hybrid strains from sturgeon farms in China. Moreover, we found that introgressive hybridization is pervasive, exists in both purebred and hybrid sturgeons, and may reflect widespread mismanagement in sturgeon breeding in China.