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This paper presents a high-precision, successive-approximation-register (SAR) analog-to-digital converter (ADC) with maximum input range of ±10 V for industry applications, where the wide-range input signal is sampled directly on part of the capacitive digital-to-analog converter (CDAC) via high-voltage (HV) sampling switches. An inherent 2-b coarse ADC is designed to avoid charge leakage under large input signal, which is reused for nonlinearity compensation from the sampling switch's resistance, while the nonlinearity due to clock feedthrough is compensated by a binary capacitor array. A capacitance reduction structure is used in the CDAC with redundant bits to save the CDAC's area. Fabricated in a 180-nm CMOS process with HV option, the ADC achieves 102-dB SNDR and 120-dB SFDR under 1.5 MSPS throughput. The overall power consumption without BGR and reference buffer is 34.4 mW under ±11-V bipolar HV supplies for sampling network and 1.8-V supply for the core circuits, corresponding to a FoMs of 175.4 dB, respectively. The entire chip occupies 7.2-mm2 area. [ABSTRACT FROM AUTHOR]

The rice field eel, Monopterus albus , is a protogynous hermaphrodite fish, in which the gonads are initially female ovaries which then transform into male testes. The exact mechanisms governing sex reversal in the rice field eel are unknown. In this study, a novel alternative splicing variant of GnRH2 ( GnRH2-SV ), retaining the second intron, was discovered in the gonad of the rice field eel. Compared to GnRH2 , GnRH2-SV may give rise to a novel truncated GnRH2-associated peptide (New GAP2). The normal transcript of GnRH2 was primarily expressed in the brain, and could also be detected in the liver, spleen, ovary, and testis. However, GnRH2-SV was only expressed in the ovary and testis. During sex reversal, GnRH2 expression levels increased significantly at late stages; however, expression levels of GnRH2-SV were lower in ovary than in ovotestis and testis. We also examined the effect of three peptides (GnRHa, GAP2, and New GAP2) on gonadal sex differentiation during the third stage of ovarian development of the rice field eel. Compared to the control group, the expression of amh increased significantly following incubation with each of the three peptides. However, only New GAP2 stimulated the expression of sox9a1 mRNA in vitro . After intraperitoneal injection of GAP2, the expression of amh , foxl2, and cyp19a1a increased significantly after 12 h; the concentration of serum 11-KT was also significantly increased at the 12 h time point. Treatment with New GAP2 significantly increased the expression of amh , dmrt1a, and sox9a1 , and also increased the concentration of serum 11-KT. After treated with GnRHa, the expression of amh , dmrt1a , sox9a1 , cyp19a1a, and foxl2 increased significantly, as did the level of serum E2. These results indicated that both GAP2 and New GAP2 play a crucial role in inducing expression changes of sex-differentiation related genes, and may be involved in the gonadal development and sex reversal in the rice field eel. [ABSTRACT FROM AUTHOR]

The rice field eel (Monopterus albus) is a protogynous hermaphroditic fish reared commercially as an aquaculture species in East Asia. Artificial breeding of rice field eels requires an abundance of adult females and males; however, the eels need to undergo a long period of female and intersexual stages before they develop into males, which results in a shortage of functional males in production practice. This study developed an artificial method for producing functional males through the oral administration of an aromatase inhibitor (AI, letrozole: 300 mg/kg feed) in juvenile fish. Histological analysis of gonadal sections of treated fish revealed the transition of primary ovaries to mature testes. During the initial period of the AI treatment, 2-month-old rice field eels were exclusively female. AI administration resulted in a significant reduction in 17β-estradiol levels and increase in testosterone and 11-ketotestosterone levels in vivo. Cell proliferation occurred in the outer layer of the gonadal epithelium, and oocytes degenerated in the ovaries. After 120 days of AI treatment, the ovaries were completely converted to testes. The sexually reversed fish maintained the male sex and produced functional sperm after cessation of drug treatment. Notably, artificially sex-reversed males' fecundity did not differ significantly from wild-type males. Quantitative PCR analysis revealed that the expression of cyp19a1a decreased, whereas the mRNA levels of estrogen receptors esr1 , esr2a , and esr2b increased significantly during AI treatment. Moreover, the expression of foxl2 was downregulated, whereas dmrt1 , amh , and sox9 were upregulated in the gonads of fish administered AI. This study revealed that endogenous estrogen synthesis plays a key role in the sex change of rice field eels, with ovaries undergoing a reversal to testes in response to estrogen insufficiency. Such artificially induced sex conversion will be of considerable value in breeding rice field eels. • Estradiol plays a key role in sex change of protogynous rice field eel. • Aromatase inhibitor treatment induces female to male sex reversal in juvenile rice field eel. • The aromatase inhibitor induced males had the equivalent fecundity with the wild males. [ABSTRACT FROM AUTHOR]

This paper presents a low-power precision bandgap reference (BGR) circuit consisting of a current-mode BGR core with piecewise exponential curvature compensation (PECC). Three differential MOS pairs operating in sub-threshold region are combined to generate the piecewise exponential current injecting into the BGR core for curvature compensation, while the voltages with different temperature dependence for three differential pairs are generated in turn from the BGR core. Together with the intrinsic first-order compensation, the proposed scheme actually realizes a 4th-order curvature compensated BGR. The current-mode structure permits the circuit's operation under sub-1V power supply. Fabricated in a 0.18-μm CMOS process, measured results for 88 samples show that the BGR achieves an average temperature coefficient of 2.69 ppm/°C (1.39 ppm/°C–8.6 ppm/°C) in the range of −40 to 125 °C after trimming. The measured line sensitivity is 0.03%/V in the supply range from 1 to 2.5 V. The current consumption is only 0.8 μA under a 1-V supply and the active area is 0.115 mm2. [ABSTRACT FROM AUTHOR]

The rice-field eel (Monopterus albus) is showing increasingly important economic value as a freshwater aquaculture fish in Asia. It is necessary to strengthen the genetic breeding research to ensure the quantity and quality of fry supply for the expanding production of rice-field eel. However, the genetic breeding research of this species is still in its infancy. In this study, a genome-wide linkage analysis was carried out to locate its growth-related genes, which may provide guidance for high-yield breeding. In addition, the linkage map was used to mount the supercontigs of the draft genome of rice-field eel. A couple of adults and their 199 six-month-old offspring were used to construct the first ultra-high density linkage map by genome-wide resequencing. The consensus map with a total length of 5161 cM includes 1,603,560 SNPs distributed in 11,522 bins, covering almost all recombination events in the population. Using this map, up to 97.91% of the supercontigs were mounted to chromosomes, which show a good collinearity with the draft genome of rice-field eel. Based on the growth-related traits of the offspring, 37 quantitative trait loci (QTLs) were identified in 18 regions of 4 linkage groups. These QTLs contained SNPs belonging to 58 candidate growth-related genes, among which anks1a , brpf3 , plch2 , creld1 , fry , slc9a1 , rragc , mst1r , pfkfb2 and dgkb are worthy of attentions. • The first ultrahigh density genetic map of rice-field eel was constructed. • The map mounted 97.91% supercontigs into chromosome level. • Thirty seven growth-related QTLs were identified in 18 regions. • Five genes (creld1, brpf3, mst1r, pfkfb2 and anks1a) worthy of attention have been discovered. [ABSTRACT FROM AUTHOR]

The rice field eel, Monopterus albus , is an important freshwater fish cultured in China. In this study, mitotic gynogenesis was induced in the rice field eel using heat shock (40.5 ± 0.5 °C for 3.5 min) on eggs activated by ultraviolet (UV) - irradiated sperm of common carp (Cyprinus carpio). Initially, the first embryonic cell cycle was identified using histological analysis. The optimal initiation time for heat shock treatment was then determined by analyzing both the diploid and normal hatching rates. Ploidy was confirmed using flow cytometry and karyotype analyses. Embryos began to enter prophase at 70 mpf (min post-fertilization) and the first cleavage was completed at 125 mpf. Both haploid and hybrid embryos died before hatching. Heat shock treatment before metaphase (75 mpf) and at telophase (100 mpf) can induce chromosome doubling and produce viable individuals. For eggs treated before metaphase, heat shock treatment at 60 mpf, corresponding to the stage of pronuclear fusion, had the highest diploid rate (33.26 ± 4.4%) and normal hatching rate (3.94 ± 0.12%). For eggs treated at telophase (100 mpf), the diploid rate was 100% and the highest normal hatching rate was 26.77%. Therefore, the optimal time to apply heat shock treatment to induce mitotic gynogenesis in the rice field eel was at telophase during the first mitosis process. This technology could potentially accelerate the development of a new breed of rice field eel. • Mitotic gynogenesis in M. albus was induced by heat shocking eggs activated by common carp sperm. • The first cell cycle in early embryogenesis stage of M. albus was identified. • Whole genome doubling by heat shock is optimum at telophase of the first cleavage. • This mitotic gynogenesis induction method is useful in the breeding of M. albus. [ABSTRACT FROM AUTHOR]

Polyploid fish have valuable applications in aquaculture, and artificial breeding of polyploids is an important field of aquatic research. In this study, fertilized eggs (65–100 min post-fertilization (mpf)) were treated with 650–750 kg/cm2 hydrostatic pressure for 3–6 min to induce tetraploidy. The optimal rates for hatching and tetraploidization of embryos were achieved at 4.70% and 23.33%, correspondingly. Flow cytometry analysis revealed that the DNA content of tetraploidized embryo cells was approximately twice that of the wild-type. The chromosome number of the tetraploidized rice field eels was 48. In this study, artificially induced tetraploid rice field eels were able to survive, with four of them reaching 20 months of age. Measurement of erythrocyte nuclei revealed that the nuclear area of erythrocytes from tetraploids increased and was approximately twice that of the diploids. Histological analysis showed that the gonads of tetraploids developed into testes, and spermatogenetic germ cells were observed. In conclusion, a technique to induce tetraploidization has been developed for rice field eels by applying 700 or 750 kg/cm2 hydrostatic pressure on 85 mpf embryos for 5 min. The viable tetraploidized rice field eels were produced using this approach. • A method for hydrostatic pressure shock-induced tetraploid rice field eel was established. • Artificially induced tetraploid rice field eels survived and grow up to adult. • The gonad of tetraploid rice field eel developed into testis and may be fertile. [ABSTRACT FROM AUTHOR]

Homozygous mutant populations are typically obtained when studying gene function using gene editing. However, because of asynchronous testicular and ovarian development, it is difficult to obtain homozygous mutant offspring of hermaphrodite fish by mating males and females. The rice field eel (Monopterus albus) was the first hermaphrodite teleost to be identified. Natural sex change characteristics render M. albus a good model for studying vertebrate sex differentiation. Rice field eels are also an economically important aquaculture species in East and Southeast Asia. In this study, we established a highly efficient multi-locus gene editing method for rice field eels. We selected cyp19a1a and foxl2 for editing and targeted seven and 11 sites in the coding regions of these genes, respectively. Fertilized eggs were co-injected with the Cas9 protein and the guide RNAs of each gene. The efficiency of gene editing–induced mutations in cyp19a1a and foxl2 was approximately 100% in the microinjected embryos and adult fish tissues. In cyp19a1a mutants, serum E 2 levels were decreased, and ovarian development was blocked. Only germ stem cells or oogonia were present in the gonads of the 12-month-old cyp19a1a mutant fish. These results suggest that cyp19a1a plays a key role in regulating primary gonadal development in the ovaries of rice field eels. In foxl2 mutants, cyp19a1a transcription and serum E 2 levels were minimally decreased, whereas the transcription of foxl2-l , foxl3 , and dmrt1 was increased. Nevertheless, the gonads of foxl2 mutant fish differentiated into ovaries, thereby indicating that foxl2 does not directly affect ovarian development in rice field eels. The multi-locus gene editing method established in this study provides an effective approach for studying gene function study and improving the genetic traits in rice field eels. • Multi-locus gene editing was performed in a hermaphroditic fish. • cyp19a1a and foxl2 was effectively knock out in Monopterus albus. • cyp19a1a plays a key role in regulating ovarian development in Monopterus albus. [ABSTRACT FROM AUTHOR]

The freshwater pearl mussel Hyriopsis cumingii is the most important mussel species for freshwater pearl production in China. Mussel shell color is an important indicator of pearl quality. The objective of this study was to assess whether total carotenoid content (TCC) in H. cumingii is related to shell color. TCC of different tissues (gonad, gill, hepatopancreas, kidney, axe foot, mantle, and adductor muscle) of purple and white inner-shell H. cumingii was determined by UV-Vis spectrophotometry. The results revealed that TCC ranged from 12.91 ± 0.78 to 56.30 ± 0.74 μg/g. In general, TCC was higher in the hepatopancreas, followed by the mantle, gonad, gill, kidney, axe foot, and adductor muscle. TCC in gonad, gill, hepatopancreas, kidney, and mantle of purple mussels was significantly higher than that of white mussels. TCC in mussel tissues of H. cumingii was significantly different ( P < 0.001) with respect to shell color. There were significant positive correlations between TCC in mussel mantle and shell color intensity. Future studies will assess the biological roles of carotenoids in shell color formation. [ABSTRACT FROM AUTHOR]

Abstract: As a molecular carrier and storage protein, apolipoprotein (Apo) mediates the intracellular uptake of lipids, proteins, vitamins and carotenoids. In this study, we identified a novel Apo gene, designated hcApo, from the freshwater pearl mussel Hyriopsis cumingii. The complete hcApo cDNA consists of 4104 nucleotides with an open reading frame encoding 1155 amino acid residues. The hcApo protein contains a conserved lipoprotein N-terminal domain (LPD-N) that is a characteristic of the large lipid transfer protein (LLTP) superfamily. The hcApo mRNA is constitutively expressed in a wide range of tissues with the highest expression level in the liver. Moreover, differential expression analysis revealed that the hcApo gene is more highly expressed in the liver, kidney, mantle and gill of purple line mussels compared to white line mussels. In situ hybridization investigations of the precise expression site of hcApo mRNA in the mantle showed that hcApo mRNA is specifically expressed in the outer epithelial cells of the middle fold and the inner epithelial cells of the outer fold of the mantle, as well as throughout the outer epithelium of the outer fold and ventral mantle. Another very important finding is that significantly positive correlation existed between the hcApo gene expression level and the total carotenoid content in purple line mussels. These findings may provide a better understanding of the roles of hcApo in the molecular mechanisms of shell formation and coloring of H. cumingii. [Copyright &y& Elsevier]

Hematology can provide valuable information for the evaluation of fish health. Rice field eel (Monopterus albus), a typical protogynous hermaphrodite fish, is famous for a fairly high nutritive value as a popular farmed fish in some Asian country, especially in China. Basic characteristics and reference values of hematology is poorly understood in M. albus , which hinder disease prevention and breeding in aquaculture. In this study, cell types, changes and typical parameters of peripheral blood were identified and systematically analyzed in M. albus during natural sex reversal. Erythrocytes, leukocytes and thrombocytes were distinguished, meanwhile, their cellular and ultrastructural features were analyzed among female, intersex and male individuals. The number and area of erythrocyte in males was significantly higher than that in both females and intersex. After detecting the serum estradiol and 11-keto testosterone level, changes of erythrocyte are the same as the trends among female, intersex and male in 11-keto testosterone level. Interestingly, dividing erythrocyte was found in the peripheral blood among the three types individuals, more dividing erythrocytes were found in intersex. The differential leukocyte count (DLC) revealed predominance of lymphocytes, followed by neutrophils and monocytes, and showed significant differences among female, intersex and male. Our findings revealed the types, cellular and ultrastructural features, and dynamic changes of blood cell during sex reversal in M. albus. It provides hematological reference for breeding, disease prevention and control in protogynous hermaphrodite fish, especially M. albus. • Reference values of growth performance, sex hormones level and hematological parameters were established in M. albus. • Dynamic changes of erythrocytes, leukocytes and thrombocytes were described during nature sex reversal. • Dividing erythrocyte was found in M. albus , it was frequently observed in intersex individuals. [ABSTRACT FROM AUTHOR]

The common carp, a gonochoristic teleost fish with an XX/XY sex-determining system, provides an excellent model for studying cyprinidae gonadal sex differentiation. The present study aims at investigating the detailed process of early gonadal sex differentiation of common carp by combining the expression patterns of sex related genes (cyp19a1a , foxl2 , amh , dmrt1 , sox9b , sycp3 , dmc1) with gonadal histological changes using mono-sex female and male Yellow River carp. H&E staining, immunohistochemistry and immunofluorescence of gonads indicated that the ovaries and testis of common carp were both directly differentiated from undifferentiated gonads. Oogonia and spermatogonia were first observed at 40 dph (days post hatching) and 70 dph in female and male gonads, respectively. Female related genes cyp19a1a and foxl2 and male related genes amh , dmrt1 and sox9b increased significantly in 30–40 dph female, and male gonads, respectively. These suggest that the critical timing of sex determination of common carp takes place between 30 and 40 dph or possibly earlier. Meiotic marker gene dmc1 and sycp3 increased expression significantly in 55 dph female gonads while sycp3 increased expression significantly in 100 dph male gonads. Oocytes in meiosis and spermatocytes were first observed in 55 dph female and 100 dph male gonads, respectively. These indicate that the initiation time of gonadal sex differentiation is 50–55 dph in female common carp and 90–100 dph in male common carp. To our knowledge, this is the first study investigating the detailed process of early gonadal sex differentiation of common carp by combining the expression patterns of sex related genes with gonadal histological changes. We have identified the critical window of sex determination and the initiation times of oogenesis and spermatogenesis in the Yellow River carp. These results provide researchers with valuable information to possibly reveal the mechanisms of sex determination and differentiation of common carp. • We successfully produced mono-sex female and male Yellow River carp. • The critical window time of sex determination of common carp is at 30-40 dph or even earlier. • Gonadal sex differentiation initiation is at 50-55 dph and 90-100 dph in females and males, respectively. • cyp19a1a and amh may be used as molecular markers for sex identification in common carp, even before sex differentiation. [ABSTRACT FROM AUTHOR]