College of Agriculture & Natural Resources

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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

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Author: search.filters.author.Liu, Jianan

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    Tributyrin, a Butyrate Pro-Drug, Primes Satellite Cells for Differentiation by Altering the Epigenetic Landscape
    (MDPI, 2021-12-09) Murray, Robert L.; Zhang, Wei; Liu, Jianan; Cooper, Jason; Mitchell, Alex; Buman, Maria; Song, Jiuzhou; Stahl, Chad H.
    Satellite cells (SC) are a population of muscle resident stem cells that are responsible for postnatal muscle growth and repair. With investigation into the genomic regulation of SC fate, the role of the epigenome in governing SC myogenesis is becoming clearer. Histone deacetylase (HDAC) inhibitors have been demonstrated to be effective at enhancing the myogenic program of SC, but their role in altering the epigenetic landscape of SC remains undetermined. Our objective was to determine how an HDAC inhibitor, butyrate, promotes myogenic differentiation. SC from tributyrin treated neonatal piglets showed a decrease relative to SC from control animals in the expression of enhance of zeste homologue-2 (EZH2), a chromatin modifier, ex vivo. Chromatin Immunoprecipitation-Sequencing (ChIP-Seq) analysis of SC isolated from tributyrin treated pigs showed a global reduction of the tri-methylation of lysine 27 of histone H3 (H3K27me3) repressive chromatin mark. To determine if reductions in EZH2 was the primary mechanism through which butyrate affects SC behavior, SC were transfected with siRNA targeting EZH2, treated with 0.5 mM butyrate, or both. Treatment with butyrate reduced paired-box-7 (Pax7) and myogenic differentiation-1 (MyoD) gene expression, while siRNA caused reductions in EZH2 had no effect on their expression. EZH2 depletion did result in an increase in differentiating SC, but not in myotube hypertrophy. These results indicate that while EZH2 reduction may force myogenic differentiation, butyrate may operate through a parallel mechanism to enhance the myogenic program.
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    DNA methylation profiles correlated to striped bass sperm fertility
    (Springer Nature, 2018-04-10) Woods, L. Curry III; Li, Yaokun; Ding, Yi; Liu, Jianan; Reading, Benjamin J.; Fuller, S. Adam; Song, Jiuzhou
    Striped bass (Morone saxatilis) spermatozoa are used to fertilize in vitro the eggs of white bass (M. chrysops) to produce the preferred hybrid for the striped bass aquaculture industry. Currently, only one source of domestic striped bass juveniles is available to growers that is not obtained from wild-caught parents and is thus devoid of any genetic improvement in phenotypic traits of importance to aquaculture. Sperm epigenetic modification has been predicted to be associated with fertility, which could switch genes on and off without changing the DNA sequence itself. DNA methylation is one of the most common epigenetic modification types and changes in sperm epigenetics can be correlated to sub-fertility or infertility in male striped bass. The objective of this study was to find the differentially methylated regions (DMRs) between high-fertility and sub-fertility male striped bass, which could potentially regulate the fertility performance. In our present study, we performed DNA methylation analysis of high-fertility and sub-fertility striped bass spermatozoa through MBD-Seq methods. A total of 171 DMRs were discovered in striped bass sperm correlated to fertility. Based on the annotation of these DMRs, we conducted a functional classification analysis and two important groups of genes including the WDR3/UTP12 and GPCR families, were discovered to be related to fertility performance of striped bass. Proteins from the WDR3/UTP12 family are involved in forming the sperm flagella apparatus in vertebrates and GPCRs are involved in hormonal signaling and regulation of tissue development, proliferation and differentiation. Our results contribute insights into understanding the mechanism of fertility in striped bass, which will provide powerful tools to maximize reproductive efficiencies and to identify those males with superior gametes for this important aquaculture species.
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    Diet-induced changes in bacterial communities in the jejunum and their associations with bile acids in Angus beef cattle
    (Springer Nature, 2020-09-16) Liu, Jianan; Liu, Fang; Cai, Wentao; Jia, Cunling; Bai, Ying; He, Yanghua; Zhu, Weiyun; Li, Robert W.; Song, Jiuzhou
    The small intestine, while serving as the main absorption organ, also possesses a unique bacterial environment and holds the critical function of conversion of primary bile acids. Bile acids are, in turn, able to regulate bacterial composition and promote the growth of bacteria that convert primary bile acids to secondary bile acids. However, in beef cattle, few studies have explored the influence of diets on jejunal bacterial communities and examined its relationships with bile acids. Here, we examined the impact of grain- and grass-based diets on jejunal and fecal bacterial communities’ composition and investigated possible association of bacterial features with bile acids. We demonstrated that the influences of diets on intestinal bacteria can be observed in young beef cattle after weaning. A significantly higher level of microbial diversity was documented in feces of grass-fed cattle comparing to grain-fed cattle. Top 20 important genera identified with random forest analysis on fecal bacterial community can be good candidates for microbial biomarkers. Moreover, the jejunal bacteria of adult Angus beef cattle exhibited significant differences in microbial composition and metabolic potential under different diets. Global balances and bacteria signatures predictive of bile acids were identified, indicative of the potential association of bacterial features with bile acids. The findings from this study provided novel insights into the relationships between jejunal bacteria and bile acids under different diets in Angus beef cattle. Our results should help us gain a better understanding of potential health benefits of grass-fed beef.
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    COMMUNITY STRUCTURES OF GUT MICROBIOME UNDER DIFFERENT DIETS IN ANGUS BEEF CATTLE
    (2019) Liu, Jianan; Song, Jiuzhou; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The microbiota of animals’ digestive tract plays important roles in health, nutrient utilization, and performance. For ruminants, the digestive tract, including rumen and other gastro-intestinal regions, hosts a unique and diverse microbiome that aids feed fermentation, digestion, and absorption. We hypothesize that compositions of diets can influence microbiomes and further affect the production of VFA and the composition of bile acids in beef cattle. We used rectum microbiota as a baseline and examined the microbiome in rumen and jejunum by16S-seq, together with quantifications of VFAs, lactate, and bile acids under grass-feeding and grain-feeding. We found that microbial communities displayed significant differences in microbiome structure and VFA production. Moreover, increased VFAs in grain-fed group may trigger lactate-associated bacteria growth. Bile acids could promote the growth of bacteria that had abilities of secondary bile acids conversion. These results provided deep insights into differences in beef quality and bovine biology under different diets.