14 results on '"Kaiping Deng"'
Search Results
2. FTO-mediated demethylation of GADD45B promotes myogenesis through the activation of p38 MAPK pathway
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Yixuan Fan, Zhibo Wang, Guomin Zhang, Feng Wang, Yu Cai, Mingtian Deng, Jianfei Shi, Yaxu Liang, Kaiping Deng, Yanli Zhang, and Jiawei Lu
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MAPK/ERK pathway ,Gene knockdown ,mitochondrial biogenesis ,Myogenesis ,Chemistry ,goat ,Skeletal muscle ,RM1-950 ,GADD45B ,myogenic differentiation ,Cell biology ,m6A modification ,medicine.anatomical_structure ,Mitochondrial biogenesis ,Drug Discovery ,Coactivator ,medicine ,Molecular Medicine ,Myocyte ,Original Article ,Therapeutics. Pharmacology ,FTO - Abstract
N6-methyladenosine (m6A) modification plays a critical role in mammalian development. However, the role of m6A in the skeletal muscle development remains largely unknown. Here, we report a global m6A modification pattern of goat skeletal muscle at two key development stages and identified that the m6A modification regulated the expression of the growth arrest and DNA damage-inducible 45B (GADD45B) gene, which is involved in myogenic differentiation. We showed that GADD45B expression increased during myoblast differentiation, whereas the downregulation of GADD45B inhibits myogenic differentiation and mitochondrial biogenesis. Moreover, the expression of GADD45B regulates the expression of myogenic regulatory factors and peroxisome proliferator-activated receptor gamma coactivator 1 alpha by activating the p38 mitogen-activated protein kinase (MAPK) pathway. Conversely, the inactivation of p38 MAPK abolished the GADD45B-mediated myogenic differentiation. Furthermore, we found that the knockdown of fat mass and obesity-associated protein (FTO) increases GADD45B m6A modification and decreases the stability of GADD45B mRNA, which impairs myogenic differentiation. Our results indicate that the FTO-mediated m6A modification in GADD45B mRNA drives skeletal muscle differentiation by activating the p38 MAPK pathway, which provides a molecular mechanism for the regulation of myogenesis via RNA methylation., Graphical abstract, Deng et al. provide the transcriptome-wide m6A map of goat skeletal muscle and demonstrate that FTO-mediated m6A modification in GADD45B mRNA drives skeletal muscle differentiation by activating the p38 MAPK pathway, which provides a molecular mechanism for the regulation of myogenesis via RNA methylation.
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- 2021
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3. Effect of Time, Temperature, and Transport Media on the Recovery of Listeria monocytogenes from Environmental Swabs
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Geethaanjali Vijayakumar, Diana Stewart, Yadwinder Singh Rana, Kaiping Deng, Lanlan Yin, Mary Lou Tortorello, and Joelle K. Salazar
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Food Handling ,Population ,Colony Count, Microbial ,medicine.disease_cause ,01 natural sciences ,Microbiology ,Matrix (chemical analysis) ,03 medical and health sciences ,chemistry.chemical_compound ,Listeria monocytogenes ,Cheese ,Transport medium ,medicine ,Food science ,education ,0303 health sciences ,education.field_of_study ,030306 microbiology ,business.industry ,010401 analytical chemistry ,Phosphate buffered saline ,Temperature ,0104 chemical sciences ,chemistry ,Sodium hypochlorite ,Ice cream ,Food Microbiology ,Food processing ,business ,Food Science - Abstract
Environmental monitoring for Listeria monocytogenes in food processing environments is key for ensuring the safety of ready-to-eat foods. For sampling, swabs are often hydrated with a wetting or transport medium that may contain neutralizers and other ingredients. After swabbing the environment, the swabs may then be transported or shipped cold to an off-site laboratory for testing, ideally within 48 h. Extended shipping times may subject the pathogen to increased temperatures in the presence of the wetting medium, organics, and other chemicals from the processing facility that could confound detection. This study evaluated growth and detection of L. monocytogenes on stainless steel exposed to either buffer or sodium hypochlorite before drying. Swabs were rehydrated with Butterfield's phosphate buffer, neutralizing buffer, Letheen broth, or Dey-Engley neutralizing broth before swabbing. Swabs were stored in the presence of no added food, cheese whey, or ice cream under both optimal (4°C) and suboptimal (15°C) temperatures for up to 72 h. Overall, there was no growth of L. monocytogenes at 4°C through 72 h of storage, although enrichment from these swabs was dependent on the presence and type of food matrix. Pathogen growth during storage at 15°C was more variable and depended on both the food matrix and transport media used, with Dey-Engley and Letheen broths allowing for the highest population increases. Overall, more enrichments resulting in L. monocytogenes detections were observed when using Letheen broth and neutralizing buffer than Dey-Engley broth, which resulted in fewer detections at 15°C. Logistic regression and Cochran-Mantel-Haenszel analyses determined that storage temperature, transport media, and food matrix all significantly affected detection of L. monocytogenes, whereas storage time did not have a clear effect on recovery from swabs. HIGHLIGHTS
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- 2021
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4. Evaluation of Inactivating Norovirus, Hepatitis A, and Listeria monocytogenes on Raspberries by Sanitizer Spray
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Kaiping Deng, Sara Swanson, Britt Burton Freeman, Alvin Lee, Nicole Maks, and Mu Ye
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0303 health sciences ,030306 microbiology ,business.industry ,Hepatitis A ,04 agricultural and veterinary sciences ,biochemical phenomena, metabolism, and nutrition ,Contamination ,medicine.disease_cause ,medicine.disease ,040401 food science ,Microbiology ,Blowing a raspberry ,03 medical and health sciences ,0404 agricultural biotechnology ,Hand sanitizer ,Control measure ,Listeria monocytogenes ,Norovirus ,medicine ,Food science ,business ,Food Science - Abstract
Reducing the risk of contamination with foodborne pathogens is paramount in maintaining safety of produce. The raspberry industry uses chlorine spray as a control measure before conveying ...
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- 2019
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5. The regulation of LncRNA GTL2 expression by DNA methylation during sheep skeletal muscle development
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Yixuan, Fan, Caifang, Ren, Kaiping, Deng, Zhen, Zhang, Juan, Li, Mingtian, Deng, Yanli, Zhang, and Feng, Wang
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Genomic Imprinting ,Sheep ,Genetics ,Animals ,RNA, Long Noncoding ,DNA Methylation ,Muscle Development ,Muscle, Skeletal - Abstract
DNA methylation has crucial roles in regulating the expression of genes involved in skeletal muscle development. However, the DNA methylation pattern of lncRNA during sheep skeletal muscle development remains unclear. This study investigated previous WGBS and LncRNA data in skeletal muscle of sheep (fetus and adult). We then focused on LncRNA GTL2, which is differentially expressed in skeletal muscle and has multiple DMRs. We found that the expression level of GTL2 decreased with age. GTL2 DMRs methylation levels were significantly higher in adult muscle than in fetal muscle. After 5AZA treatment, GTL2 expression was significantly increased in a dose-dependent manner.The dCas9-DNMT3A-sgRNA significantly reduced the expression level of GTL2 in cells, but increased GTL2 DMR methylation levels. The above studies indicate that dCas9-DNMT3A can effectively increase the methylation level in the DMR region of GTL2, the expression level of GTL2 is regulated by DNA methylation during muscle development.
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- 2022
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6. Role of FGF9 in sheep testis steroidogenesis during sexual maturation
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Xiaoxiao Gao, Feng Wang, Hua Yang, Guomin Zhang, Yi-Xuan Guo, Xiaolei Yao, Ting-Ting Zhang, and Kaiping Deng
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Fibroblast Growth Factor 9 ,Male ,0301 basic medicine ,Biology ,Fibroblast growth factor ,Andrology ,03 medical and health sciences ,Endocrinology ,Food Animals ,FGF9 ,Complementary DNA ,Testis ,Gene expression ,Animals ,Sexual maturity ,Testosterone ,Sexual Maturation ,Peptide sequence ,chemistry.chemical_classification ,Sheep ,Leydig Cells ,General Medicine ,Spermatids ,Amino acid ,stomatognathic diseases ,Fertility ,030104 developmental biology ,chemistry ,Animal Science and Zoology ,Development of the gonads - Abstract
Fibroblast growth factor 9 (FGF9) is an important signaling molecule in early gonadal development. Hu sheep are noted for reproductive precociousness and fertility. The present study was conducted to investigate the gene expression and functions of FGF9 in ovine testis steroidogenesis during sexual maturity. A 874 bp cDNA fragment of FGF9 was detected that included a 627 bp coding sequence, encoding 208 amino acids. The FGF9 amino acid sequence of sheep had high homology with this molecule of other mammalian species. Additionally, the abundance of FGF9 in ovine testis was greater (P 0.05) at 9 months (M) and 24 M of age compared with those at 3 M. Immunohistochemistry further revealed that FGF9 mainly localized in the Leydig cells and that there were small amounts in elongating spermatids. The functions of FGF9 in sheep Leydig cells was investigated using a siRNA-FGF9. Secretion of T and abundance of testosterone synthesis-related enzymes in Leydig cells were inhibited (P 0.05) by siRNA-FGF9. Thus, these results demonstrated FGF9 is an important regulator of testosterone biosynthesis in rams. Results of the present research provide a new perspective for genetic and molecular research on modulation of physiological mechanisms during sexual maturity in male sheep.
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- 2018
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7. Effects of perilla frutescens seed supplemented to diet on fatty acid composition and lipogenic gene expression in muscle and liver of Hu lambs
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Tiewei Ma, Wenjing TanTai, Kaiping Deng, Haitiao Nie, Zhen Wang, Yixuan Fan, Feng Wang, and Yi-Xuan Guo
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0301 basic medicine ,Perilla frutescens ,General Veterinary ,Triglyceride ,0402 animal and dairy science ,Blood lipids ,04 agricultural and veterinary sciences ,Metabolism ,Biology ,Perilla ,biology.organism_classification ,040201 dairy & animal science ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Animal science ,chemistry ,Adipocyte ,Gene expression ,Animal Science and Zoology ,Fatty acid composition - Abstract
The objective of this study was to determine the effect of perilla (perilla frutescens L.) seed (PFS) supplementation on serum lipids metabolism, intramuscular adipocyte size, fatty acid composition and lipogenic genes expression in muscle and liver of Hu lambs. Sixty male Hu lambs (23.02 ± 1.36 kg body weight and approximately 3 months of age) were randomly assigned to four dietary treatments receiving diets containing 0%, 5%, 10% or 15% perilla seed (CD, 5%PFSD, 10%PFSD and 15%PFSD, respectively). During the 84 days experimental period, these groups were fed the assigned diets ad libitum. Compared with CD group, LDL-cholesterol, total cholesterol, and triglyceride levels in the serum significantly (P
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- 2018
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8. Effects of diet and arginine treatment during the luteal phase on ovarian NO/PGC-1α signaling in ewes
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Haitao Nie, Guomin Zhang, Feng Wang, Kaiping Deng, Yixuan Fan, Ling-Wei Sun, and Yi-Xuan Guo
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0301 basic medicine ,medicine.medical_specialty ,Arginine ,Ovary ,Luteal Phase ,Luteal phase ,Biology ,Nitric Oxide ,03 medical and health sciences ,Food Animals ,Internal medicine ,medicine ,Animals ,Small Animals ,Estrous cycle ,Sheep ,Equine ,0402 animal and dairy science ,04 agricultural and veterinary sciences ,Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ,040201 dairy & animal science ,030104 developmental biology ,Endocrinology ,medicine.anatomical_structure ,Gene Expression Regulation ,Animal Nutritional Physiological Phenomena ,Female ,Animal Science and Zoology ,Food Deprivation ,Signal Transduction - Abstract
The aim of this study was to determine whether arginine (Arg) supplementation of malnourished ewes affects the expression of key NO/PGC-1α signaling pathway genes in the ovary. On Day 6-15 of the estrous cycle, 24 multiparous Hu sheep (BW = 43.56 ± 1.53 kg) were randomly assigned to three groups: control group (CG; n = 6), restriction group (RG; n = 9) and l-arginine group (AG; n = 9), and administered Arg treatment (or vehicle) three times per day. The ewes were slaughtered at the end of treatment, and blood samples and ovaries were collected for analysis. The results of our analyses showed that both short-term feed-restriction and/or supplementation with L-Arg-HCl affected the number of different size follicles observed in the ovary, and the relative day of estrus behavior initiation of ewes. Specifically, the relative day of estrus behavior initiation was significantly advanced in AG compared with that in RG ewes (P 0.05). Both the number of ≤2 mm-ovarian follicles (P 0.05) and the total number of ovarian follicles (P 0.05) were significantly increased in the RG and AG compared with that in the CG ewes. RG ewes exhibited a higher proportion of ≤2 mm (P 0.05), but a lower proportion of5 mm follicles than did CG ewes (P 0.05). The mean number of corpus lutea ≥5 mm was significantly increased in AG as compared to that in either CG or RG ewes. Furthermore, the expression of eNOS, nNOS, iNOS, PDE5A, PDE9A, PRKG2, and PPARGC1A varied significantly among the treatment groups (P 0.05). GUCY1A3 mRNA levels were significantly increased in RG and AG as compared to those in CG ewes (P 0.05), whereas conversely, GUCY1B3 mRNA levels were significantly decreased in CG and RG as compared to those in AG ewes (P 0.05). P53 mRNA levels were found to vary significantly among the three experimental treatment groups (P 0.05), and similarly, the relative expression levels of P53 were greater in AG and RG than in CG ewes (P 0.05). The levels of eNOS protein were significantly higher in RG than in either CG or AG ewes (P 0.05). The relative expression levels of PGC-1α were significantly higher in RG (P 0.05) and significantly lower in AG ewes (P 0.05) than in CG ewes. In conclusion, the results of the present study indicate that feed-restriction negatively affects follicular development, and that Arg-supplementation may modulate the expression of key NO/PGC-1α signaling pathway genes in the ovary and thereby accelerate ovulatory processes and the estrous rate. Elucidation of mechanisms underlying these effects of Arg on gene expression in the ewe ovary requires further investigation.
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- 2017
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9. Guidelines To Validate Control of Cross-Contamination during Washing of Fresh-Cut Leafy Vegetables
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Ruth L. Petran, Yaguang Luo, Joan C. Rosen, G. Shergill, Kaiping Deng, R. Varley, R. Walsh, J. Brennan, B. Zomorodi, K. Khurana, D. Gombas, and H. Hau
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0301 basic medicine ,Food Handling ,business.industry ,Preventive control ,030106 microbiology ,Colony Count, Microbial ,Food Contamination ,04 agricultural and veterinary sciences ,Microbial contamination ,Contamination ,040401 food science ,Microbiology ,Hazard ,Biotechnology ,Food and drug administration ,03 medical and health sciences ,0404 agricultural biotechnology ,Wash water ,Vegetables ,Food Microbiology ,Food processing ,Environmental science ,Leafy vegetables ,business ,Food Science - Abstract
The U.S. Food and Drug Administration requires food processors to implement and validate processes that will result in significantly minimizing or preventing the occurrence of hazards that are reasonably foreseeable in food production. During production of fresh-cut leafy vegetables, microbial contamination that may be present on the product can spread throughout the production batch when the product is washed, thus increasing the risk of illnesses. The use of antimicrobials in the wash water is a critical step in preventing such water-mediated cross-contamination; however, many factors can affect antimicrobial efficacy in the production of fresh-cut leafy vegetables, and the procedures for validating this key preventive control have not been articulated. Producers may consider three options for validating antimicrobial washing as a preventive control for cross-contamination. Option 1 involves the use of a surrogate for the microbial hazard and the demonstration that cross-contamination is prevented by the antimicrobial wash. Option 2 involves the use of antimicrobial sensors and the demonstration that a critical antimicrobial level is maintained during worst-case operating conditions. Option 3 validates the placement of the sensors in the processing equipment with the demonstration that a critical antimicrobial level is maintained at all locations, regardless of operating conditions. These validation options developed for fresh-cut leafy vegetables may serve as examples for validating processes that prevent cross-contamination during washing of other fresh produce commodities.
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- 2017
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10. FTO regulates myoblast proliferation by controlling CCND1 expression in an m6A-YTHDF2-dependent manner
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Yixuan Fan, Xiaoxiao Gao, Yaxu Liang, Caifang Ren, Kaiping Deng, Zhen Zhang, and Feng Wang
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0301 basic medicine ,Gene knockdown ,Myoblast proliferation ,biology ,Cell growth ,Cellular differentiation ,nutritional and metabolic diseases ,Cell Biology ,Cell cycle ,Cell biology ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Cyclin D1 ,030220 oncology & carcinogenesis ,biology.protein ,Gene silencing ,Demethylase - Abstract
N6-Methyladenosine (m6A) modification is the most abundant chemical modification in mRNA, and it participates in various biological processes, such as cell differentiation and proliferation. However, little is known about the function of m6A demethylase fat mass and obesity-associated (FTO) in myoblast proliferation. Here, we demonstrated that knockdown of FTO can significantly inhibit myoblast proliferation and promote apoptosis. RNA sequencing analysis revealed that a lot of downregulated genes in FTO knockdown cells are associated with cell cycle and apoptosis. Furthermore, silencing FTO drastically decreased cyclin D1 (CCND1) expression through YTHDF2-mediated mRNA degradation, thereby delaying the progression of G1 phase, and leading to impaired myoblast proliferation. These findings unraveled that FTO regulates myoblast proliferation by controlling CCND1 expression in an m6A-YTHDF2-dependent manner, which highlights the critical roles of m6A modification in myoblast proliferation.
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- 2021
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11. Effects of spirulina supplementation on lipid metabolism disorder, oxidative stress caused by high-energy dietary in Hu sheep
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Yaxu Liang, Yongjin Bao, Kaiping Deng, Yixuan Fan, Feng Wang, Dong Liu, Xinai Huang, Xiaoxiao Gao, Shiyu An, Zhibo Wang, and Zhinan Liu
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Antioxidant ,Lipid Metabolism Disorder ,medicine.medical_treatment ,Lipid Metabolism Disorders ,Oxidative phosphorylation ,medicine.disease_cause ,Random Allocation ,0404 agricultural biotechnology ,Animal science ,White blood cell ,Spirulina ,Animals ,Medicine ,Muscle, Skeletal ,Sheep, Domestic ,Triglycerides ,Spirulina (genus) ,biology ,business.industry ,Metabolic disorder ,0402 animal and dairy science ,Lipid metabolism ,04 agricultural and veterinary sciences ,medicine.disease ,biology.organism_classification ,Animal Feed ,040401 food science ,040201 dairy & animal science ,Blood Cell Count ,Diet ,Oxidative Stress ,Cholesterol ,medicine.anatomical_structure ,Immunoglobulin G ,business ,Oxidative stress ,Food Science - Abstract
The aim of this study was to investigate the effect of spirulina supplementation in a high-energy (HE) diet on lipid metabolism, oxidative status and immunity in Hu lambs. The lambs were assigned to two groups receiving either a standard diet (ST) or a HE diet. Each group was divided into three subgroups: no spirulina supplementation (control), 1% spirulina supplementation, or 3% spirulina supplementation. The body fat, serum cholesterol, triacylglycerol and oxidative stress increased in lambs fed the HE diet. However, 3% spirulina supplementation in the HE diet reduced above parameters and enhanced antioxidant capacity, including increased SOD activity and T-AOC content in serum and Longissimus thoracis et lumborum (LTL). Additionally, lambs receiving 3% spirulina supplementation showed an improvement in immunity-related parameters, including increased IgG concentration in serum and red and white blood cell counts. In conclusion, 3% spirulina supplementation in HE diet ameliorated lipid metabolic disorder and oxidative stress caused by a HE diet.
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- 2020
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12. miR-27a is an important adipogenesis regulator associated with differential lipid accumulation between intramuscular and subcutaneous adipose tissues of sheep
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Zifei Liu, P. You, Caifang Ren, Yanwen Zhang, Kaiping Deng, Feng Wang, Yixuan Fan, and Guomin Zhang
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medicine.medical_specialty ,Peroxisome proliferator-activated receptor gamma ,Adipose tissue ,Alpha (ethology) ,Retinoid X receptor ,03 medical and health sciences ,0302 clinical medicine ,Endocrinology ,Food Animals ,Lipid droplet ,Internal medicine ,microRNA ,Adipocytes ,medicine ,Animals ,Adipogenesis ,Retinoid X Receptor alpha ,Sheep ,030219 obstetrics & reproductive medicine ,Retinoid X receptor alpha ,Chemistry ,0402 animal and dairy science ,04 agricultural and veterinary sciences ,Lipid Metabolism ,040201 dairy & animal science ,PPAR gamma ,MicroRNAs ,Adipose Tissue ,Gene Expression Regulation ,Body Composition ,Animal Science and Zoology - Abstract
Micro ribonucleic acids (miRNAs) are crucial regulators for various biological processes. Despite important function in the proliferation and differentiation of preadipocytes, miRNA studies are limited in regional differences in adipogenesis. Here, we show that miR-27a plays an important role in regulating differential lipid accumulation between intramuscular (IM) and subcutaneous (SC) adipose tissues in sheep. Invivo, we observed that miR-27a expression in IM adipose tissue is more abundant than in SC adipose tissue. However, the expression of Peroxisome Proliferator-Activated Receptor Gamma (PPARG) and retinoid X receptor alpha (RXR alpha) in IM adipose tissue was significantly lower than that in SC adipose tissue. In the ovine preadipocyte differentiation model, we found that the expression of miR-27a was significantly decreased in differentiated ovine adipocytes. Overexpression of miR-27a significantly downregulated the expression of PPARG and RXR alpha and suppressed the accumulation of triglyceride but promoted the proliferation of ovine preadipocytes. Whereas, inhibition of miR-27a suppressed preadipocyte proliferation but enhanced PPARG and RXR alpha expression and lipid droplet formation. In addition, dual-luciferase activity assays showed that RXR alpha was a direct target of miR-27a. Thus, miR-27a enhances ovine preadipocytes proliferation and inhibits ovine preadipocytes differentiation through regulating the expression of target RXR alpha. Collectively, our study demonstrates the functional importance of miR-27a in ovine adipogenesis and provides novel insights into exploring regional differences in adipogenesis.
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- 2020
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13. Behavior Of Shiga Toxigenic Escherichia coli Relevant to Lettuce Washing Processes and Consideration Of Factors for Evaluating Washing Process Surrogates
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Kaiping Deng, Hongliu Ding, Li Han Yen, Mary Lou Tortorello, and Xue Wang
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Microbial Viability ,Shiga-Toxigenic Escherichia coli ,Food Handling ,Colony Count, Microbial ,chemistry.chemical_element ,Food Contamination ,Lettuce ,Contamination ,Biology ,Antimicrobial ,Microbiology ,PEDIOCOCCUS PENTOSACEUS ,Lactic acid ,chemistry.chemical_compound ,chemistry ,Consumer Product Safety ,polycyclic compounds ,Colony count ,Chlorine ,Postharvest ,Disinfectants ,Food Science - Abstract
Postharvest processes for fresh produce commonly include washing in water containing antimicrobial chemicals, such as chlorine; however, if the antimicrobials are not present in sufficient levels, washing can promote the spread of contamination that might be present. To understand cross-contamination risk during washing, we tested a collection of Shiga toxigenic Escherichia coli (STEC), including O157:H7 and other non-O157 strains, for certain traits during washing of fresh-cut lettuce, i.e., sensitivity to sublethal chlorine levels and ability to cross-contaminate (detach from and attach to) lettuce in the presence of sublethal chlorine levels. Nonpathogenic E. coli Nissle 1917 (EcN) and Pediococcus pentosaceus lactic acid bacterial species (LAB) were included as potential washing process validation surrogates. As measured by extension of the lag phase of growth in media containing 0.15 ppm of chlorine, chlorine sensitivity varied among the STECs. Cross-contamination was assessed by evaluating transfer of bacteria from inoculated to uninoculated leaves during washing. Without chlorine, similar transfer to wash water and uninoculated leaves was shown. In 1 ppm of chlorine, cross-contamination was not detected with most strains, except for the substantial transfer by a STEC O111 strain and EcN in some replicates. Strain O111 and EcN showed less inactivation in 0.25 ppm of chlorine water compared with O157 (P0.05). LAB showed similar transfer and similar chlorine inactivation to O157. Considering together the sublethal chlorine sensitivity and detachment/attachment traits, neither EcN nor LAB displayed optimal characteristics as washing process surrogates for the STEC strains, although further evaluation is needed. This work demonstrated a range of behaviors of STEC strains during lettuce washing and may be helpful in hazard characterization, identifying factors to consider for evaluating washing process efficacy, and identifying phenotypic traits to select surrogates to validate washing processes.
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- 2014
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14. Investigation of the Interaction among the Components of the Cytolethal Distending Toxin of Haemophilus ducreyi
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Eric J. Hansen, David A. Lewis, Kaiping Deng, and Jo L. Latimer
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Cytolethal distending toxin ,Macromolecular Substances ,Bacterial Toxins ,Blotting, Western ,Biophysics ,Biochemistry ,Chromatography, Affinity ,Bacterial cell structure ,Microbiology ,Protein–protein interaction ,law.invention ,Haemophilus ducreyi ,Structure-Activity Relationship ,Affinity chromatography ,law ,Escherichia coli ,Humans ,Molecular Biology ,Gene ,Immunosorbent Techniques ,biology ,Cell Biology ,biology.organism_classification ,Recombinant Proteins ,In vitro ,Protein Subunits ,Recombinant DNA ,Biological Assay ,Electrophoresis, Polyacrylamide Gel ,HeLa Cells ,Protein Binding - Abstract
The cytolethal distending toxin (CDT) of Haemophilus ducreyi is encoded by the cdtABC genes, but the composition of active CDT is not known. Both immunoaffinity and metal affinity chromatographic methods were used to purify H. ducreyi CDT from recombinant Escherichia coli strains bearing wild-type or mutated H. ducreyi cdtABC genes. Both affinity-purified preparations contained CdtA, CdtB, and CdtC proteins. These purification efforts also revealed that the formation of a noncovalent CdtB-CdtC complex and production of a fully active CDT complex required the presence of a functional CdtA protein. When purified recombinant CdtB and CdtC proteins were mixed, only very slight CDT activity was detected. In contrast, when a bacterial cell extract containing CdtA was mixed with purified preparations of both CdtB and CdtC, full CDT activity was reconstituted in vitro. These results indicate that CdtA is essential for normal H. ducreyi CDT activity and that CdtA likely modifies or alters either CdtB or CdtC or both to form the active CDT complex.
- Published
- 2001
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