Transcriptomic and metabolic analysis unveils the mechanism behind leaf color development in Disanthus cercidifolius var. longipes.

Introduction: Leaf coloration in Disanthus cercidifolius var. longipes results from the interplay of various pigments undergoing complex catalytic reactions. Methods: We aimed to elucidate the mechanisms of pigment biosynthesis affecting leaf color transition in D. cercidifolius var. longipes by analyzing variations in pigment accumulation and levels of gene expression. Results: We identified 468, 577, and 215 differential metabolites in green leaves (GL), gradual-color-changing leaves (GCCL), and red leaves (RL), respectively, with 94 metabolites shared across all comparisons. Metabolite accumulation patterns were similar among GL, GCCL, and RL, with flavonoids being the main differential metabolites. Delphinidin, malvidin, and petunidin derivatives were mostly accumulated in GCCL, whereas cyanidin, pelargonidin, and peonidin derivatives accumulated in RL. Transcriptome sequencing was used to identify differentially expressed genes. The expression of anthocyanin biosynthetic pathway genes was associated with anthocyanin accumulation patterns. Discussion: Our findings reveal that the content of delphinidin, malvidin, petunidin, and carotenoids collectively determines the gradual transition of leaf color from green in spring and summer to green, purple, and orange-yellow in early autumn, whereas the content of cyanidin, peonidin, pelargonidin, and carotenoids together causes the autumnal transition to red or orange-red colors as leaves of D. cercidifolius var. longipes age.

Cebp1 and Cebpß transcriptional axis controls eosinophilopoiesis in zebrafish.

Eosinophils are a group of granulocytes well known for their capacity to protect the host from parasites and regulate immune function. Diverse biological roles for eosinophils have been increasingly identified, but the developmental pattern and regulation of the eosinophil lineage remain largely unknown. Herein, we utilize the zebrafish model to analyze eosinophilic cell differentiation, distribution, and regulation. By identifying eslec as an eosinophil lineage-specific marker, we establish a Tg(eslec:eGFP) reporter line, which specifically labeled cells of the eosinophil lineage from early life through adulthood. Spatial-temporal analysis of eslec+ cells demonstrates their organ distribution from larval stage to adulthood. By single-cell RNA-Seq analysis, we decipher the eosinophil lineage cells from lineage-committed progenitors to mature eosinophils. Through further genetic analysis, we demonstrate the role of Cebp1 in balancing neutrophil and eosinophil lineages, and a Cebp1-Cebpß transcriptional axis that regulates the commitment and differentiation of the eosinophil lineage. Cross-species functional comparisons reveals that zebrafish Cebp1 is the functional orthologue of human C/EBPεP27 in suppressing eosinophilopoiesis. Our study characterizes eosinophil development in multiple dimensions including spatial-temporal patterns, expression profiles, and genetic regulators, providing for a better understanding of eosinophilopoiesis.

Influence of geographic origin and tissue type on the medicinal chemical compounds of Semiliquidambar cathayensis.

Semiliquidambar cathayensis is widely used in traditional Chinese medicine owing its high concentrations of polyphenol, triterpenoidic acid, and flavonoids. This study aimed to explore the impact of geographical origin and tissue type on the contents of chemical compounds of S. cathayensis, as determined by colorimetric and chromatographic methods. Therefore, we quantitively evaluated chemical compounds found in the tissues of various organs of plants collected in six different regions. Overall, we found that geographical origin affected the content of medicinal compounds in S. cathayensis leaves, with plants from Jingzhou county showing the best therapeutic potential. However, no specific correlation was observed with latitude. It is noteworthy that the amount of paeoniflorin and other compounds can be used as biomarkers of geographical origin and tissue type. Most medicinal compounds accumulated mainly in the leaves, whereas ursolic and oleanolic acids accumulated in the roots. These results show that the comprehensive medicinal value of the leaves of S. cathayensis in Jingzhou county is the highest, but the root should be selected first to collect oleanolic acid and ursolic acid.

Schizophrenia Patients With Prevotella-Enterotype Have a Higher Risk of Obesity.

Recent studies have indicated the critical influence of gut microbiota on the occurrence of obesity. There is a significant risk of obesity in people with schizophrenia. This work proposed that the disorder of gut microbiota in patients with schizophrenia was based on microbial enterotypes. Ninety-seven patients with schizophrenia and 69 matched health controls were eligible. The fresh feces of all the subjects were collected and used to complete 16S rRNA sequence. Statistical analysis was performed to identify the intestinal type of gut microbiota and analyze their potential effects on metabolic function. The patients with enterotype-P had a higher BMI than that of the others. Several differences in the gut microbes of enterotype-P were found between the patients and the controls. Proteobacteria and Firmicutes had significantly higher abundance in the patients' group with enterotype-P. The Bacteroidetes had higher abundance in health controls with enterotype-P. Different metabolic pathways of the microbiota with the enterotype-P were identified in the subjects categorized in different BMI intervals. The schizophrenia patients had a significantly higher BMI than that of health controls. The patients with enterotype-P had a higher BMI. Therefore, the enterotype-P might have a critical influence on a variety of metabolic pathways to disturb the metabolism of glucose and lipid in human body.

Comparative transcriptome analysis of leaf, stem, and root tissues of Semiliquidambar cathayensis reveals candidate genes involved in terpenoid biosynthesis.

BACKGROUND: Semiliquidambar cathayensis is a traditional medicinal plant and endemic species in China. Its roots, branches, leaves, bark, and nectar are known to have therapeutic effects against rheumatoid arthritis, lumbar muscle strain, and several other diseases. However, limited knowledge regarding the molecular properties of S. cathayensis highlights the need for further research in order to elucidate the underlying pathways governing the synthesis of its active ingredients and regulation of its accumulation processes. METHODS: We conducted transcriptome sequencing of the leaf, stem and root epidermises, and stem and root xylems of S. cathayensis with three biological replicates. Moreover, candidate genes involved in terpenoid biosynthesis, such as IDI, FPPS, DXR, SQS, GPPS, and HMGR were selected for quantitative real-time PCR analysis. RESULTS: We identified 88,582 unigenes. Among which, 36,144 unigenes were annotated to the nr protein database, 21,981 to the Gene Ontology database, 11,565 to the Clusters of Orthologous Groups database, 24,209 to the Pfam database, 21,685 to the SWISS-PROT database, and 12,753 to the Kyoto Encyclopedia of Genes and Genomes (KEGG), with 5072 unigenes common to all six databases. Of those annotated using the KEGG database, 187 unigenes were related to the terpenoid metabolism pathway, and expression analysis of the related genes indicated that the mevalonate and methylerythritol 4-phosphate pathways play different roles in terpenoid biosynthesis in different tissues of S. cathayensis. CONCLUSIONS: These findings greatly expand gene resources of S. cathayensis and provide basic data for the study of the biosynthetic pathways and molecular mechanisms of terpenoids.

Loss of Ripk3 attenuated neutrophil accumulation in a lipopolysaccharide-induced zebrafish inflammatory model.

Neutrophils are important effector cells during inflammation, which play complex roles. Therefore, investigating the regulation of neutrophil accumulation during inflammation might provide targets for treating related diseases. In the present study, we generated a ripk3-deficient zebrafish line to study the roles of Ripk3 in neutrophil-related inflammation. The homeostatic hematopoiesis and cytokine expression of the ripk3-deficient larvae were unaltered. The ripk3-deficient larvae with caudal fin fold injury exhibited similar neutrophil enrichment with wild-type larvae, suggesting that Ripk3 is not essential for non-infectious inflammatory responses. When challenged with lipopolysaccharide (LPS), the ripk3-deficient larvae showed significantly less neutrophil accumulation in the injection site and differential expression of several key cytokines. Ripk3 inhibitors could also attenuate neutrophil accumulation in wild-type larvae, indicating that Ripk3 could serve as a candidate target for inflammation treatment. In summary, our study indicated that Ripk3 has an essential role in LPS-induced inflammatory responses. It was suggested that the ripk3-deficient zebrafish might be applied in developing infectious disease models, while Ripk3 also has potential as an inflammation-treatment target.

The change of gut microbiota in MDD patients under SSRIs treatment.

The alterations in the gut microbiota have been reported to be correlated with the development of depression. The purpose of this study was to investigate the changes of intestinal microbiota in depressed patients after antidepressant treatment. We recruited 30 MDD patients (MDD group) and 30 healthy controls (control group). The MDD group received individualized treatment with escitalopram at a maximum dose of 20 mg/day. After depressive symptoms improved to a HAMD scale score > 50%, a fecal sample was collected again and used as the follow-up group. The differences of gut microbiota between patients and controls, the characteristics of gut microbiota under treatment and the potential differences in metabolic functions were thus investigated. The Firmicutes/Bacteroidetes ratio was significantly different within three groups, and the ratio of follow-up group was significantly lower than those of the other two groups. Alpha diversity was significantly higher in MDD group than those of the other groups, and the alpha diversity was not significantly different between control and follow-up groups. The beta diversity of some patients resembled participants in the control group. The metabolic function of gut microbiota after treatment was still different from that of the control group. This study suggests that the intestinal flora of depressed patients has a tendency to return to normal under escitalopram treatment.

Slc20a1b is essential for hematopoietic stem/progenitor cell expansion in zebrafish.

Hematopoietic stem and progenitor cells (HSPCs) are able to self-renew and can give rise to all blood lineages throughout their lifetime, yet the mechanisms regulating HSPC development have yet to be discovered. In this study, we characterized a hematopoiesis defective zebrafish mutant line named smu07, which was obtained from our previous forward genetic screening, and found the HSPC expansion deficiency in the mutant. Positional cloning identified that slc20a1b, which encodes a sodium phosphate cotransporter, contributed to the smu07 blood phenotype. Further analysis demonstrated that mutation of slc20a1b affects HSPC expansion through cell cycle arrest at G2/M phases in a cell-autonomous manner. Our study shows that slc20a1b is a vital regulator for HSPC proliferation in zebrafish early hematopoiesis and provides valuable insights into HSPC development.

Possible association of Firmicutes in the gut microbiota of patients with major depressive disorder.

BACKGROUND: Gut microbiota can affect human behavior and mood in many ways. Several studies have shown that patients with depression were also accompanied with gut microbiota disorder, in which Firmicutes are related to the protective function of intestinal barrier. In this study, we explore the changes and effects of Firmicutes in the patients with major depressive disorder (MDD). METHOD: We recruited 54 subjects, including 27 patients with MDD. Fecal samples were collected for identification by 16S rRNA sequencing and bioinformatics analysis. RESULTS: The study shows that the alpha diversity indices of MDD patients are lower than those of the healthy controls. Firmicutes is the most significantly decreased phylum in the MDD samples. There are totally 13 taxonomic biomarkers with P-value <0.01 from Firmicutes. There are differences in 17 KEGG pathways between the two groups. CONCLUSION: This study found that there is a significant disorder of gut microbiota in the patients with depression, in which the Firmicutes decreased significantly. Defects of the Firmicutes may lead to the depression in short-chain fatty acids, which could account for the physiological basis of low-level inflammation of depression. LIMITATIONS: This is a cross-sectional study and the sample size is comparatively small. Though several diet-related factors were controlled in the study, there is no quantified assessment of it.

Two Distinct Interferon-γ in the Orange-Spotted Grouper (Epinephelus coioides): Molecular Cloning, Functional Characterization, and Regulation in Toll-Like Receptor Pathway by Induction of miR-146a.

Interferon gamma (IFNγ) is a Th1 cytokine that is critical for innate and adaptive immunity. Toll-like receptors (TLRs) signaling pathways are critical in early host defense against invading pathogens. miR-146a has been reported to participate in the regulation of host immunity. The known mechanisms of integrations between the IFNγ and TLR signaling pathways are incompletely understood, especially in teleosts. In this study, orange-spotted grouper (Epinephelus coioides) IFNγ1 and IFNγ2, their biological activities, especially their involvements in TLR pathway, were explored. We identified and cloned two IFNγ genes of E. coioides, namely EcIFNγ1 and EcIFNγ2. The produced recombinant E. coioides IFNγ1 (rEcIFNγ1) and IFNγ2 (rEcIFNγ2) proteins showed functions, which are similar to those of other bony fishes, such as enhancing nitric oxide responses and respiratory burst response. rEcIFNγ2 could regulate TLR pathway by enhancing the promoter activity of miR-146a upstream sequence and thus increasing the expression level of miR-146a, which possibly targets TNF receptor-associated factor 6 (TRAF6), a key adapter molecule in TLR signaling pathway. Taken together, these findings unravel a novel regulatory mechanism of anti-inflammatory response by IFNγ2, which could mediate TLR pathway through IFNγ2-miR-146a-TRAF6 negative regulation loop. It is suggested that IFNγ2 may provide a promising therapeutic, which may help to fine tune the immune response.

High Performance of PEDOT:PSS/n-Si Solar Cells Based on Textured Surface with AgNWs Electrodes.

Hybrid heterojunction solar cells (HHSCs) have gained extensive research and attention due to simple device structure and low-cost technological processes. Here, HHSCs are presented based on a highly transparent conductive polymer poly(3,4ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) directly spin-coated on an n-type crystalline silicon with microscale surface textures, which are prepared by traditional chemical etching. We have studied interface properties between PEDOT:PSS and textured n-Si by varying coating conditions. Final power conversion efficiency (PCE) could arrive at 8.54% by these simple solution-based fabrication processes. The high conversion efficiency is attributed to the fully conformal contact between PEDOT:PSS film and textured silicon. Furthermore, the reflectance of the PEDOT:PSS layer on textured surface is analyzed by changing film thickness. In order to improve the performance of the device, silver nanowires were employed as electrodes because of its better optical transmittance and electrical conductivity. The highest PCE of 11.07% was achieved which displayed a 29.6% enhancement compared with traditional silver electrodes. These findings imply that the combination of PEDOT:PSS film and silver nanowire transparent electrodes pave a promising way for realizing high-efficiency and low-cost solar cells.

Estrogen directly stimulates LHb expression at the pituitary level during puberty in female zebrafish.

The LHb expression is up-regulated during puberty in female zebrafish. However, the molecular mechanism underlying how LHb expression is regulated during puberty remains largely unknown. In this study, we found that the mRNA expression levels of lhb, fshb and cyp19a1b were up-regulated along with the puberty onset in zebrafish. Among the three nuclear estrogen receptors (nERs), the esr2b is the only type whose expression is significantly up-regulated during puberty onset in the pituitary. However, in situ hybridization results revealed that lhb mRNA was colocalized with esr1 and esr2a but not esr2b. Exposure to estradiol (E2) significantly stimulates LHb expression in both wild-type and kiss1-/-;kiss2-/-;gnrh3-/- triple knockout pubertal zebrafish. Moreover, exposure of cultured pituitary cells to E2 increased the LHb expression, indicating that the estrogenic effect on LHb expression could be acted at the pituitary level. Finally, we cloned and analyzed the promoter of lhb by luciferase assay. Our results indicated that the E2 responsive regions of lhb promoter for ERα and ERß2 are identical, suggesting that ERα and ERß2 could bind to the same half ERE region of the promoter of lhb, exhibiting a classical ERE-dependent pathway. In summary, we demonstrate that E2 could directly act on the pituitary level to stimulate LHb transcription during puberty in zebrafish.

Fertility impairment with defective spermatogenesis and steroidogenesis in male zebrafish lacking androgen receptor.

The pivotal role of androgen receptor (AR) in regulating male fertility has attracted much research attention in the past two decades. Previous studies have shown that total AR knockout would lead to incomplete spermatogenesis and lowered serum testosterone levels in mice, resulting in azoospermia and infertility. However, the precise physiological role of ar in controlling fertility of male fish is still poorly understood. In this study, we have established an ar knockout zebrafish line by transcription activator-like effectors nucleases. Homozygous ar mutant male fish with smaller testis size were found to be infertile when tested by natural mating. Intriguingly, a small amount of mature spermatozoa was observed in the ar mutant fish. These mature spermatozoa could fertilize healthy oocytes, albeit with a lower fertilization rate, by in vitro fertilization. Moreover, the expression levels of most steroidogenic genes in the testes were significantly elevated in the ar mutants. In contrast, the levels of estradiol and 11-ketotestosterone (11-KT) were significantly decreased in the ar mutants, indicating that steroidogenesis was defective in the mutants. Furthermore, the protein level of LHß in the serum decreased markedly in the ar mutants when compared with wild-type fish, probably due to the positive feedback from the diminished steroid hormone levels.

New Insights Into the Role of Estrogens in Male Fertility Based on Findings in Aromatase-Deficient Zebrafish.

It has been demonstrated that estrogens are indispensable for male fertility in mammals. Aromatase (encoded by CYP19) catalyzes the final step of estradiol biosynthesis. However, less is known about the role of aromatase in male fertility in nonmammalian species. Fish aromatase is encoded by two separate genes: the gonad-specific cyp19a1a and the brain-specific cyp19a1b. In a recent study, we used transcription activatorlike effector nucleases to systematically generate cyp19a1a and cyp19a1b mutant lines and a cyp19a1a;cyp19a1b double-mutant line in zebrafish and demonstrated that cyp19a1a was indispensable for sex differentiation. In this study, we focused on male fertility in these aromatase-deficient zebrafish. Our results showed that all aromatase-deficient male fish had normal fertility even at 1 year after fertilization. Interestingly, we observed more spermatozoa in the cyp19a1a and double-mutant males than in the wild-type and cyp19a1b mutant males. The whole-body androgen levels, follicle-stimulating hormone ß and luteinizing hormone ß protein levels in the pituitary, and transcript levels of genes known to be involved in spermatogenesis and steroidogenesis in the testes were significantly higher in the cyp19a1a mutant and aromatase double-mutant males than in the wild-type and cyp19a1b mutant males. These results might explain why more spermatozoa were observed in these fish. Collectively, our findings indicate that estrogens are not needed to achieve and maintain normal fertility in male zebrafish. This finding challenges the traditional view that estrogens are indispensable for male fertility.

Targeted Disruption of Aromatase Reveals Dual Functions of cyp19a1a During Sex Differentiation in Zebrafish.

Aromatase (encoded by the cyp19a1a and cyp19a1b genes) plays a central role in sex differentiation in fish, but its precise roles during sex differentiation are still largely unknown. Here, we systematically generated cyp19a1a and cyp19a1b mutant lines as well as a cyp19a1a;cyp19a1b double mutant line in zebrafish using transcription activatorlike effector nucleases. Our results showed that cyp19a1a mutants and cyp19a1a;cyp19a1b double mutants, but not cyp19a1b mutants, had impaired sex differentiation, and all cyp19a1a mutants and cyp19a1a;cyp19a1b double mutants were males. During sex differentiation, the ovary-like gonads were not observed and the male sex differentiation program was delayed in the cyp19a1a-null fish, and these phenotypes could be partially rescued by 17ß-estradiol treatment. Gene expression analysis indicated that male and female sex differentiation-related genes were significantly decreased in the cyp19a1a mutant. Collectively, our results revealed dual functions of the cyp19a1a gene during sex differentiation: cyp19a1a is not only indispensable for female sex differentiation but also required for male sex differentiation.

Molecular mechanism of feedback regulation of 17ß-estradiol on two kiss genes in the protogynous orange-spotted grouper (Epinephelus coioides).

Kisspeptins are considered critical regulators in the hypothalamic-pituitary-gonadal axis because they can stimulate secretion of Gonadotropin-releasing hormone in mammals, and may also mediate the feedback regulation of sex steroids in the hypothalamus. Two kiss1 paralogues (kiss1 and kiss2) were identified in teleosts, hinting at their increased complexity of signaling for sex-steroid feedback regulation. In the present study, molecular pathways by which 17ß-estradiol (E2 ) exerted feedback regulation on two kiss genes, via three types of estrogen receptors, were investigated in the protogynous orange-spotted grouper (Epinephelus coioides). kiss2 expression in the brain significantly increased in ovariectomized orange-spotted groupers, while E2 replacement in ovariectomized fish reversed these changes to levels in the sham-surgery group; conversely, kiss1 expression did not change. Dual-label in situ hybridization showed that kiss1 and kiss2 neurons express erα, erß1, and erß2, indicating that E2 may directly regulate kiss1 and kiss2. Indeed, E2 treatment of transiently transfected HEK293T cells decreased the activity of both kiss promoters in the presence of erß1 and erß2 rather than erα. Further deletion and site-directed mutagenesis of the kiss promoters indicated that kiss1 is regulated by E2 via an estrogen-responsive element (ERE)-dependent, classical pathway utilized by Erß1, as well as via an Activator protein 1 (Ap1)-dependent, non-classical pathway utilized by Erß2. kiss2 was also differently regulated by E2 through the Creb transcription factor, utilized by Erß1 as well as a half-ERE-dependent, classical pathway utilized by Erß2. Taken together, multiple signaling pathways in orange-spotted grouper are clearly involved in the feedback regulation of E2 on kiss genes via different estrogen receptors.

LH signaling induced ptgs2a expression is required for ovulation in zebrafish.

It is well known that ovulation is induced by luteinizing hormone (LH) surge. However, the down-stream factors that mediating LH surge induced ovulation are less clear. The cyclooxygenases (also known as PTGS) as key enzymes for prostaglandins synthesis appear to be important for ovulation in mammals, but their functional roles and molecular mechanism in regulation of fish ovulation are largely unexplored. In this study, we have systematically investigated the expression, regulation and functional roles of cox genes during zebrafish ovulation. Three types of cox genes including ptgs1, ptgs2a and ptgs2b have been identified in zebrafish. The ptgs2a was dominantly expressed in the ovary with a maximal level at the maturation stage of the follicles. In addition, the ptgs2a expression is up-regulated by LH signaling in vitro and in vivo. Moreover, co-injection of a selective Ptgs2 inhibitor and non-selective Ptgs inhibitor with hCG could significantly block the stimulatory effect of hCG induced ovulation in vivo. Collectively, our findings indicate that LH signaling induced ptgs2a expression is required for ovulation in zebrafish.

Molecular identification of StAR and 3ßHSD1 and characterization in response to GnIH stimulation in protogynous hermaphroditic grouper (Epinephelus coioides).

Gonadal steroids are critical factors in reproduction and sex reverse process. StAR (steroidogenic acute regulatory protein), transferring the cholesterol from the outer mitochondrial membrane to the inner membrane, is the rate-limiting factor of steroidogenesis. 3ßHSD (3ß-hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase), converting Δ5-steroids into Δ4-steroids, is an important oxidoreductase in steroidogenesis. In the present study, StAR and 3ßHSD1 were cloned and characterized from protogynous orange-spotted grouper. StAR cDNA contains an 861bp open reading frame (ORF), encoding a predicted protein of 286 amino acids, and the ORF of 3ßHSD1 was 1125bp, encoding a predicted protein of 374 amino acids. The transcript of StAR was mainly expressed in gonad, while 3ßHSD1 mRNA was predominantly detected in brain and gonad. In the previous study, we found the expression of GnIH mRNA level in male, as well as in 17 alpha-methyltestosterone (MT)-induced male fish was significantly higher than in female fish, this indicating that GnIH/GnIHR signaling might be involved in the regulation of sex reversal and male maintenance. In order to figure out the function of GnIH in steroidogenesis, the expression of StAR and 3ßHSD1 regulated by GnIH was examined. In vitro study showed that treatment of cultured ovary fragments with gGnIH peptides significantly stimulated the expression of StAR and 3ßHSD1. In addition, the mRNA levels of StAR and 3ßHSD1 were significantly increased after intraperitoneal injection (i.p.) with gGnIH peptides. Moreover, during MT-induced sex change from female to male, the levels of StAR mRNA significantly increased by 5.2, 24.8 and 353.5 folds, and that of 3ßHSD1 mRNA by 3.5, 32.5 and 55.4 folds at the 2nd, 4th and 6th week after MT implantation, respectively. Collectively, our results indicate that GnIH may be involved in the regulation of sex reversal or male maintenance by stimulating the expression of StAR and 3ßHSD1 in protogynous grouper.

Tetraodon nigroviridis: A model of Vibrio parahaemolyticus infection.

Vibriosis is the most common bacterial diseases and brings great economic loss on aquaculture. Vibrio parahaemolyticus (V. parahaemolyticus), a gram-negative bacterium, has been identified as one main pathogens of Vibriosis. The pathogenic mechanism of V. parahaemolyticus is not entirely clear now. In our study, a model of V. parahaemolyticus infection of green-spotted puffer fish (Tetraodon nigroviridis) was established. T. nigroviridis were injected intraperitoneally (i.p.) with 200 µL of V. parahaemolyticus (8 × 10(10) CFU/mL). V. parahaemolyticus infection caused 64% mortality and infected some organs of T. nigroviridis. Histopathology studies revealed V. parahaemolyticus infection induced tissue structural changes, including adipose hollow space in the liver. Immunohistochemistry showed V. parahaemolyticus were present in infected tissue such as liver, head kidney and spleen. In livers of T. nigroviridis infected by V. parahaemolyticus, the alkaline phosphatases (ALP) activity first gradually increased and then backed to normal level, a trend that was on the contrary to the expression profile of the miR-29b. Quantitative real-time PCR analysis showed that the expression level of TLR1, TLR2, TLR5, TLR9, TLR21, NOD1, NOD2 and IL-6 in response to V. parahaemolyticus infection decreased compared to that of non-infected fish. The establishment of the T. nigroviridis model of V. parahaemolyticus infection further confirmed V. parahaemolyticus spreads through the blood circulation system primary as an extracellular pathogen. Meanwhile, liver is an important target organ when infected by V. parahaemolyticus. miR-29b in liver was involved in the progress of liver steatosis during V. parahaemolyticus infection. Moreover, V. parahaemolyticus infection in vivo may have an effect of immunosuppression on host.

Gene knockout of nuclear progesterone receptor provides insights into the regulation of ovulation by LH signaling in zebrafish.

It is well established that the luteinizing hormone surge triggers ovulation, a dynamic process leading to the release of the mature oocyte from the ovarian follicle. But how this process controlled by LH signaling remains largely unknown in non-mammalian species. In this study, we investigated the roles of nuclear progesterone receptor (npr) in LH-induced ovulation. Our results indicate that the nuclear progesterone receptor serves as an important mediator of LH action on ovulation. This conclusion is based on the following results: (1) the expression level of npr peaks at the full-grown stage of the follicles; (2) the expression of npr is stimulated by LH signaling in vitro and in vivo; and (3) the npr null females are infertile due to ovulation defects. Moreover, we further show that LH signaling could induce ptger4b expression in an npr-dependent manner, and blockage of Ptger4b could also block hCG-induced ovulation. Collectively, our results not only demonstrate that npr serves an indispensable role in mediating the action of LH on ovulation in zebrafish, but also provide insights into the molecular mechanisms of the regulation of ovulation in fish.