Genetic mechanism of body size variation in groupers:Insights from phylotranscriptomics

Animal body size variation is of particular interest in evolutionary biology,but the genetic basis remains largely unknown.Previous studies have shown the presence of two parallel evolutionary genetic clusters within the fish genus Epinephelus with evident divergence in body size,providing an excellent opportunity to investigate the genetic basis of body size variation in vertebrates.Herein,we performed phylotranscriptomic analysis and reconstructed the phylogeny of 13 epinephelids originating from the South China Sea.Two genetic clades with an estimated divergence time of approximately 15.4 million years ago were correlated with large and small body size,respectively.A total of 180 rapidly evolving genes and two positively selected genes were identified between the two groups.Functional enrichment analyses of these candidate genes revealed distinct enrichment categories between the two groups.These pathways and genes may play important roles in body size variation in groupers through complex regulatory networks.Based on our results,we speculate that the ancestors of the two divergent groups of groupers may have adapted to different environments through habitat selection,leading to genetic variations in metabolic patterns,organ development,and lifespan,resulting in body size divergence between the two locally adapted populations.These findings provide important insights into the genetic mechanisms underlying body size variation in groupers and species differentiation.

Single-cell RNA sequencing reveals gonadal dynamic changes during sex differentiation in hermaphroditic protogynous orange-spotted grouper(Epinephelus coioides)

DEAR EDITOR,Sex differentiation is a complex process that requires many factors to regulate gonadal proliferation, differentiation,development, and organization. In teleosts, the molecular mechanisms of sex differentiation are diverse and unclear.

Long-read genome assemblies reveal a cis-regulatory landscape associated with phenotypic divergence in two sister Siniperca fish species

Due to the difficulty in accurately identifying structural variants(SVs) across genomes,their impact on cisregulato ry diverge n ce of closely related species,especially fish,remains to be explored.Recently identified broad H3K4me3 domains are essential for the regulation of genes involved in several biological processes.However,the role of broad H3K4me3 domains in phenotypic divergence remains poorly understood.Siniperca chuatsi and S.scherzeri are closely related but divergent in several phenotypic traits,making them an ideal model to study cis-regulatory evolution in sister species.Here,we generated chromosome-level genomes of S.chuatsi and S.scherzeri,with assembled genome sizes of 716.35 and740.54 Mb,respectively.The evolutionary histories of S.chuatsi and S.scherzeri were studied by inferring dynamic changes in ancestral population sizes.To explore the genetic basis of adaptation in S.chuatsi and S.scherzeri,we performed gene family expansion and contraction analysis and identified positively selected genes(PSGs).To investigate the role of SVs in cis-regulatory divergence of closely related fish species,we identified high-quality SVs as well as divergent H3K27ac and H3K4me3 domains in the genomes of S.chuatsi and S.scherzeri.Integrated analysis revealed that cis-regulatory divergence caused by SVs played an essential role in phenotypic divergence between S.chuatsi and S.scherzeri.Additionally,divergent broad H3K4me3 domains were mostly associated with cancer-related genes in S.chuatsi and S.scherzeri and contributed to their phenotypic divergence.

Full-length transcriptome sequence and SSR marker development for genetic diversity research in yellowfin seabream Acanthopagrus latus

Yellowfin seabream Acanthopagrus latus is an important economic fish in Chinese coastal areas.Given its narrow distribution and overfishing,the genetic diversity of yellowfin seabream has been restricted for artificial breeding and reproduction.We performed full-length transcriptome sequencing and assembly of the genome of yellowfin seabream.A total of 68086 unigenes were obtained,with an N50 of 3391 bp on average length of 2933 bp.A total number of 50593 expressed sequence tags linked to simple sequence repeats(EST-SSR)were identified,among them dinucleotide repeats(40.6%)and AC/GT motifs(38.5%)were the most frequent.Of the 190 EST-SSRs for which PCR primer pairs were designed,150 primer pairs successfully amplified target loci and 15 SSRs showed high polymorphism.The alleles per locus ranged 6-50 on average of 25.3.The expected and observed heterozygosity varied from 0.632 to 0.969 and from 0.519 to 0.953,respectively.The polymorphic index content(PIC)values of each locus ranged 0.587-0.966 on average of 0.851.Among six yellowfin seabream population samples preliminarily tested for genetic diversity and differentiation,the Fangchenggang(FCG)population in Guangxi Province had the highest mean observed heterozygosity(H_(o))value(0.786),whereas the Zhangzhou(ZZ)population in Fujian Province had the lowest(0.678).The pairwise fixation index(Fst)values indicated significant population differentiation among six yellowfin seabream populations.This study provided evidence for the usefulness of the transcriptomic resource information and EST-SSR markers for natural resource conservation,population genetics,and breeding studies of yellowfin seabream in South China.

Excess dietary cholesterol may have an adverse effect on growth performance of early post-larval Litopenaeus vannamei

One experiment was conducted to determine the nutritive value of cholesterol for post-larval shrimp, Litopenaeus vannameL Four isoenergetic and isonitrogenous diets supplemented with four levels of cholesterol （D1, D2, D3 and D4 with 0, 0.5%, 1% and 2% cholesterol, respectively） were fed to triplicate groups of L. vannamei shrimp （mean initial wet weight 0.8 mg） for 27 days. After the trial, shrimp fed the D1 diet had the best growth performance （final body weights： FBW; weight gain： WG; specific growth rate： SGR）, while there was no significant difference between diet treatments with respect to survival. The whole body crude protein level in the shrimp decreased with the increase in dietary cholesterol levels, while the whole body crude lipid level in shrimps in the D4 diet treatment was significantly higher （P 〈 0.05） than in other diet treatments. Dietary analysis indicated that the D1 diet contained 0.92% cholesterol prior to supplementation, which may have satisfied the dietary cholesterol requirement of post-larval L. vannamei; excess dietary cholesterol may thus lead to adverse effects on the growth performance of post-larval shrimp.

Carotenoids in Aquaculture:An Overview

Recent studies on the role of carotenoids in aquaculture have investigated their function in regulating pigmentation, growth, survival, and immune activity of aquatic animals. These carotenoids include astaxanthin, canthaxanthin, lutein, zeaxanthin, and tunaxanthin. Astaxanthin and canthaxanthin are the main synthetic carotenoids used world-wide in the aquaculture industry. They play an important role in protecting cells and organisms against photosensitized oxidations. Direct evidence of carotenoids functioning as antioxidants in vivo has been reported in animal models. In addition to their established biological effects as antioxidants, carotenoids appear to have a great variety of cellular actions that make them remarkable physiological modulators. Consequently, recent attention has been focused on improving our understanding of carotenoids on the physiology and metabolism in aquatic animals with a view to enhance the efficacy of astaxanthin as a carotenoid pigment. This review aims to summarize the function and research progress of carotenoids in aquaculture. We discuss the methods used to study the absorption, transport, metabolic transformation and deposition of carotenoids, and their spatial and temporal expression.

Comparative transcriptomic analysis of Macro brachium nippon ense in response to Aerom onas veronii or Staphylococcus au reus infection

Macrobrachium nipponense is an economically important freshwater prawn that is often threatened by many aquatic pathogens.In this study,comparative transcriptomic analysis was fi rstly used to explore the transcriptional response of M.nipponense to Aeromonas veronii or Staphylococcus aureus stimulation.A total of 400.19 million clean reads were obtained and assembled into 56944 unigenes with an average length of 1253 bp.A total of 1857 diff erentially expressed genes were found after A.veronii infection,including 677 genes that were up-regulated and 1180 genes that were down-regulated,while 1061 signifi cant diff erentially expressed genes were identifi ed after S.aureus infection,including 390 up-regulated and 671 down-regulated genes.Many immune-related genes including Spaetzle,prophenoloxidase activating factor,C-type lectin,anti-lipopolysaccharide factor,and inhibitor of apoptosis 2 protein were commonly up-regulated after A.veronii or S.aureus infection.This study will enrich our understanding of the immune response to gram-positive and gram-negative bacteria infection in crustaceans.

Observation of Traditional Chinese Medicine's Anti-bacterial Effect on the Main Pathogenic Bacteria of Dairy Cow Recessive Mastitis

[Objective]This paper aimed to study the anti-bacterial effect of traditional Chinese medicine on cow recessive mastitis＇ s main pathogenic bacteria and provide basis for its clinical application.[Method]Plating and test-tube methods were used to determine the anti-bacterial diameter,minimum inhibitory concentration（MIC）and minimum bactericidal concentration（MBC）of 20 kinds of traditional Chinese medicine on dairy cow recessive mastitis＇ s clinically isolated main pathogenic bacteria,Staphylococcus aureus and Streptococcus agalactiae.[Conclusion]The results indicated that 7 kinds of traditional Chinese medicine,Herba Taraxaci,Rhizoma Coptidis,Fructus Forsythiae,Herba Andrographis,Radix Scutellar iae,Flos Carthami,Flos Chrysanthemi Indici had strong anti-bacterial effect.

The Investigation of Main Pathogens Causing Dairy Cattle Recessive Mastitis in Eastern Hebei

[Objective]This paper aimed to determine the main pathogens causing dairy cattle recessive mastitis in eastern Hebei and provide certain reference for local veterinarians and cow farmers to prevent and cure the disease.[Method]512 cows from 5 different farms in eastern Hebei were selected,and LMT,milk ph test and somatic cell direct counting methods were combined and used to conduct recessive mastitis＇ s epidemiological investigation,as well as isolate and identify the pethogens.[Result]The results indicated that the incidence of recessive mastitis is 60.7%（311 / 512）,bacteria isolation rate reached 87.8%（273 /311）.Total 81 isolates,belonging to 3 classes and 5 types were identified in milk samples of positive milk area from 273 cows with recessive mastitis.Among which,19 isolates were Streptococcus,accounting for 23.45%.Staphylococcus had 31 isolates,accounting for 38.27%.Enterobacter had 3,accounting for 3.7%.Other unshaped had 28 isolates,accounting for 34.6%.[Conclusion] The main pathogens caused dairy cattle recessive mastitis in eastern Hebei were Streptococcus agalactiae and Staphylococcus aureus.

Canine Cutaneous Mast Cell Tumor: Biologic Behavior and Its Correlation with Prognostic Indicators

Cutaneous mast cell tumor (MCT) shows a variable biological behavior in dogs and may present either as solitary masse that can be treated and cured with surgical removal or as a systemic metastatic and fatal disease. Histological grade, KIT pattern and proliferative index are typically prognostic factors in MCTs. In the present study, we have investigated correlation between clinical data (breed, age, gender, tumour location, tumor size, time before surgery, number of tumours, occurrence of metastasis and recurrence), cellular proliferation (Ki-67, mitotic index), intratumoural microvessel density (IMVD) and apoptotic index with the histological grade and KIT pattern. 28 tumors, from 20 dogs with cutaneous MCT were evaluated. There was association between histological grade, IMVD, tumor ulceration and number of tumors. A significant increase of Ki-67 expression and mitotic index was observed in MCTs with cytoplasmic KIT staining pattern. Patnaik histological grade system was related to mitotic index. Histological grade in canine cutaneous MCT should not be assessed as the only prognostic factor, but associated with KIT pattern, IMDV, cellular proliferation, presence of tumour ulceration, number of tumours, recurrences and metastases.

Application of ICT in Art Education： A Case Study of HIFA

This paper intends to expound the application of information and communication technology （ICT） in art education, making a case of study of Hubei Institute of Fine Arts （HIFA）. Despite financial pressure, HIFA has invested heavily in the infi＇aslructure. The classrooms at HIFA can be roughly divided into three kinds： studios, multimedia classrooms and computer labs with reference to ICT. There are three general approaches to the instructional use of the technology at HIFA, namely： learning about computers and the Intemet; learning with computers and the Intemet and learning through computers and the Internet. The utilization oflCT has shaped the art education model of HIFA considerably and has brought about a lot of changes and benefits to the faculty and students. However, its disadvantage may overweigh the advantage unless it is properly harnessed.

Research on the Performance Assessment Mechanism of Accurate Poverty Alleviation in Vocational Education

Vocational education is an effective way to achieve accurate poverty alleviation and get rid of intergenerational poverty.Vocational education is mainly to train skilled talents,not only to provide academic education for the children of poor families,but also to use a skill to achieve employment.It is of great necessity to implement accurate poverty alleviation in vocational education,and performance assessment is a very important part of the accurate poverty alleviation work of vocational education.This paper mainly analyzes the predicament of accurate poverty alleviation in vocational education and the problems in the construction of performance assessment system for accurate poverty alleviation in vocational education,and puts forward measures to improve the accurate poverty alleviation assessment system for vocational education and strengthen the accurate of vocational education.

DDAH1 promotes neurogenesis and neural repair in cerebral ischemia

Choline acetyltransferase(ChAT)-positive neurons in neural stem cell(NSC)niches can evoke adult neurogenesis(AN)and restore impaired brain function after injury,such as acute ischemic stroke(AIS).However,the relevant mechanism by which ChAT+neurons develop in NSC niches is poorly understood.Our RNA-seq analysis revealed that dimethylarginine dimethylaminohydrolase 1(DDAH1),a hydrolase for asymmetric NG,NG-dimethylarginine(ADMA),regulated genes responsible for the synthesis and transportation of acetylcholine(ACh)(Chat,Slc5a7 and Slc18a3)after stroke insult.The dual-luciferase reporter assay further suggested that DDAH1 controlled the activity of ChAT,possibly through hypoxia-inducible factor 1α(HIF-1α).KC7F2,an inhibitor of HIF-1α,abolished DDAH1-induced ChAT expression and suppressed neurogenesis.As expected,DDAH1 was clinically elevated in the blood of AIS patients and was positively correlated with AIS severity.By comparing the results among Ddah1 general knockout(KO)mice,transgenic(TG)mice and wild-type(WT)mice,we discovered that DDAH1 upregulated the proliferation and neural differentiation of NSCs in the subgranular zone(SGZ)under ischemic insult.As a result,DDAH1 may promote cognitive and motor function recovery against stroke impairment,while these neuroprotective effects are dramatically suppressed by NSC conditional knockout of Ddah1 in mice.

Bacterial and eukaryotic community interactions might contribute to shrimp culture pond soil ecosystem at different culture stages

Sedimentary bacterial and eukaryotic communities are major components of the aquatic ecosystem.Revealing the linkages between their community structure and interactions is crucial to understand the diversity and functions of aquatic and soil ecosystems.However,how their diversity and assembly contribute to their interactions on time scale is unclear.This study examined sedimentary bacterial and eukaryotic communities in shrimp culture ponds at different culture stages.The most abundant bacteria were Proteobacteria(38.27%),whereas the most abundant eukaryotes were Chytridiomycota(27.48%).Bacterial and eukaryotic diversities were correlated(P<0.05),implying the strong interactions between bacteria and eukaryotes.Results showed that the bacterial and eukaryotic communities became increasingly similar on a local scale along with the shrimp culture.Only the eukaryotic community significantly increased in similarity along with the shrimp culture(P<0.05),suggesting that the sedimentary eukaryotic community structure is sensitive under shrimp culture.Co-occurrence network modeling indicated that positive microbial interactions were dominant.The homogeneous selection was the major driver of community assembly.Bacterial diversity negatively correlated with operational taxonomic units and positive links in networks(P<0.05),whereas eukaryotic diversities positively correlated with positive links in networks(P<0.05).This study broadens our knowledge about sedimentary microbial diversity,community assembly,and interaction patterns on time scale,providing a reference for the sustainable management in aquaculture production.

Genetic analysis of the reproductive axis in fish using genome-editing nucleases

Reproduction in fish is controlled by the brain-pituitary-gonad reproductive axis. Although genes of the reproductive axis are conserved from fish to humans, their in vivo functions are less clear in fish. Mutant lines of the reproductive axis have been systematically investigated in zebrafish and medaka using recently developed genome-editing nucleases. Here, we review recent progress in the genetic analysis of the reproductive axis in fish as well as the opportunities and challenges of applying genome-editing nucleases in fisheries.

Smooth muscle AKG/OXGR1 signaling regulates epididymal fluid acid–base balance and sperm maturation

Infertility is a global concern attributed to genetic defects,lifestyle,nutrition,and any other factors that affect the local metabolism and niche microenvironment of the reproductive system.2-Oxoglutarate receptor 1(OXGR1)is abundantly expressed in the testis;however,its cellular distribution and biological function of OXGR1 in the male reproductive system remain unclear.In the current study,we demonstrated that OXGR1 is primarily expressed in epididymal smooth muscle cells(SMCs).Aging and heat stress significantly reduced OXGR1 expression in the epididymis.Using OXGR1 global knockout and epididymal-specific OXGR1 knockdown models,we revealed that OXGR1 is essential for epididymal sperm maturation and fluid acid–base balance.Supplementation ofα-ketoglutaric acid(AKG),the endogenous ligand of OXGR1,effectively reversed epididymal sperm maturation disorders caused by aging and heat stress.Furthermore,in vitro studies showed that AKG markedly stimulated the release of instantaneous intracellular calcium from epididymal SMCs and substantially reduced the pH_(i) value in the epididymal SMCs via OXGR1.Mechanistically,we discovered that AKG/OXGR1 considerably increased the expression of Na^(+)/HCO_(3)^(−)cotransporter(NBCe1)mRNA in the epididymal SMCs,mediated by intracellular calcium signaling.The local AKG/OXGR1 system changed the epididymal fluid pH value and HCO_(3)^(−)concentration,thereby regulating sperm maturation via intracellular calcium signaling and NBCe1 mRNA expression.This study for the first time reveals the crucial role of OXGR1 in male fertility and sheds light on the applicability of metabolic intermediates in the nutritional intervention of reproduction.