Chromosome-level genome assembly of largemouth bass (Micropterus salmoides) using PacBio and Hi-C technologies

The largemouth bass (Micropterus salmoides) has become a cosmopolitan species due to its widespread introduction as game or domesticated fish. Here a high-quality chromosome-level reference genome of M. salmoides was produced by combining Illumina paired-end sequencing, PacBio single molecule sequencing technique (SMRT) and High-through chromosome conformation capture (Hi-C) technologies. Ultimately, the genome was assembled into 844.88 Mb with a contig N50 of 15.68 Mb and scaffold N50 length of 35.77 Mb. About 99.9% assembly genome sequences (844.00 Mb) could be anchored to 23 chromosomes, and 98.03% assembly genome sequences could be ordered and directed. The genome contained 38.19% repeat sequences and 2693 noncoding RNAs. A total of 26,370 protein-coding genes from 3415 gene families were predicted, of which 97.69% were functionally annotated. The high-quality genome assembly will be a fundamental resource to study and understand how M. salmoides adapt to novel and changing environments around the world, and also be expected to contribute to the genetic breeding and other research.info:eu-repo/semantics/publishedVersio

T-helper type-2 contact hypersensitivity of Balb/c mice aggravated by dibutyl phthalate via long-term dermal exposure.

OBJECTIVE: During the last few decades, the prevalence of allergic skin diseases, asthma and rhinitis, has increased worldwide. Introduction of environmental chemicals with aggravation effects may play a part in this increase. The artificial chemical product dibutyl phthalate (DBP) is used in many products used in daily life. Dermal exposure to DBP is a common (but easily neglected) exposure pattern. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we examined the aggravation effect of long-term dermal exposure to DBP in a T-helper type 2 (Th2) model of contact hypersensitivity (CHS) in mice, and sought the potential molecular mechanisms. Experimental tests were conducted after 40-day dermal exposure to saline or three concentrations of DBP and subsequent three times of sensitization with 0.5% fluorescein isothiocyanate (FITC) or vehicle. The results of immunological and inflammatory biomarkers (total-immunoglobulin (Ig)E and Th cytokines) as well as histopathological examination and measurement of ear swelling supported the notion that high doses of DBP may promote and aggravate atopic dermatitis. Increased expression of thymic stromal lymphopoietin (TSLP) in this mouse model suggested that TSLP might be one of the molecular mechanisms of the aggravation effect induced by DBP. CONCLUSIONS/SIGNIFICANCE: Together, these results indicated that long-term dermal exposure to types of environmental toxins such as phthalates may endow an atopic predisposition in animals or humans. In addition, the high expression of TSLP in the mouse model demonstrated that TSLP might have an important role in the aggravation effect. This result could help to provide effective prevention strategies against atopic diseases such as atopic dermatitis (AD)

Dietary sodium acetate and sodium butyrate attenuate intestinal damage and improve lipid metabolism in juvenile largemouth bass (Micropterus salmoides) fed a high carbohydrate diet by reducing endoplasmic reticulum stress

High-carbohydrate (HC) diets decrease the intestinal levels of sodium acetate (SA) and sodium butyrate (SB) and impair the gut health of largemouth bass; however, SA and SB have been shown to enhance immunity and improve intestinal health in farmed animals. Thus, the present study was to investigate the effects of dietary SA and SB on HC diet-induced intestinal injury and the potential mechanisms in juvenile largemouth bass. The experiment set five isonitrogenous and isolipidic diets, including a low-carbohydrate diet (9% starch) (LC), a high carbohydrate diet (18% starch) (HC), and the HC diet supplemented with 2 g/kg SA (HCSA), 2 g/kg SB (HCSB) or a combination of 1 g/kg SA and 1 g/kg SB (HCSASB). The feeding experiment was conducted for 8 weeks. A total of 525 juvenile largemouth bass with an initial body weight of 7.00 ± 0.20 g were used. The results showed that dietary SA and SB improved the weight gain rate and specific growth rate (P < 0.05) and ameliorated serum parameters (alkaline phosphatase, acid phosphatase, glutamate transaminase, and glutamic oxaloacetic transaminase) (P < 0.05). And, importantly, dietary SA and SB repaired the intestinal barrier by increasing the expression levels of zonula occludens-1, occludin, and claudin-7 (P < 0.05), reduced HC-induced intestinal damage, and alleviated intestinal inflammation and cell apoptosis by attenuating HC-induced intestinal endoplasmic reticulum stress (P < 0.05). Further results revealed that dietary SA and SB reduced HC-induced intestinal fat deposition by inhibiting adipogenesis and promoting lipolysis (P < 0.05). In summary, this study demonstrated that dietary SA and SB attenuated HC-induced intestinal damage and reduced excessive intestinal fat deposition in largemouth bass

Effect of skin exposure to DBP on TSLP expression in the ear.

<p>**: <i>p</i><0.01, compared with the saline group; ##: <i>p</i><0.01, compared with the FITC group; &&: <i>p</i><0.01 compared with the FITC+DBP 4 group.</p

Effects of skin exposure to DBP on the protein expression of Th Cytokines in the ear.

<p>(A) Levels of IFN-γ. (B) Levels of IL-4. (C) Levels of IL-17A. (D) Levels of TNF-α. **: <i>p</i><0.01, compared with the saline group; ##: <i>p</i><0.01, compared with the FITC group; &&: <i>p</i><0.01 compared with the FITC+DBP 4 group.</p

Immunohistochemical analyses.

<p>Representative images of the expression of (A) IL-5 and (B) IL-13 as determined by immunohistochemical staining (brown color stain) (black arrow). Panel: (A1, B1) Saline, (A2, B2) DBP 0.4, (A3, B3) DBP 4, (A4, B4) DBP 40, (A5, B5) FITC, (A6, B6) FITC+DBP 0.4, (A7, B7) FITC+DBP 4, (A8, B8) FITC+DBP 40. Analyses of (C) IL-5 and (D) IL-13 expression levels according to average optical density. Animal groups (in all panels): n = 4 mice per group. **: <i>p</i><0.01, compared with saline group; ##: <i>p</i><0.01, compared with FITC group.</p

Serum IgE levels.

<p>**: <i>p</i><0.01, compared with the saline group; ##: <i>p</i><0.01, compared with the FITC group; &&: <i>p</i><0.01 compared with the FITC+DBP 4 group.</p

Effects of skin exposure to DBP on histological changes in the ear.

<p>(A) Stained with hematoxylin & eosin (H&E). (B) Stained with toluidine blue, degranulation mast cells were stained purple color (black arrow). (C) Number of inflammatory cells infiltrating. (D) Number of mast cells degranulating. In (A) and (B), A1–A8 or B1–B8 represent different exposure groups (saline, DBP 0.4, DBP 4, DBP 40, FITC, FITC+DBP 0.4, FITC+DBP 4, FITC+DBP 40). **: <i>p</i><0.01, compared with the saline group; ##: <i>p</i><0.01, compared with the FITC group.</p

Effects of skin exposure DBP on skin lesions induced by FITC.

<p>(A) Measurement results of ear swelling. (B) Measurement results of differences in bilateral ear weight. **: <i>p</i><0.01, compared with the saline group; ##: <i>p</i><0.01, compared with the FITC group; &&: <i>p</i><0.01 compared with the FITC+DBP 4 group.</p

Graphical summary of the study.

<p>Graphical summary of the study.</p