Development of a Method Based on Surface Enhanced Laser Desorption and Ionization Time of Flight Mass Spectrometry for Rapid Identification of Klebsiella pneumoniae

Daiwen Xiao,Yongchang Yang,Hua Liu,Hua Yu,Yingjun Yan,Wenfang Huang,Wei Jiang,Weijin Liao,Qi Hu,Bo Huang 한국미생물학회 2009 The journal of microbiology Vol.47 No.5

A method based on surface enhanced laser desorption and ionization time of flight mass spectrometry (SELDI-TOF MS) was developed for the rapid identification of Klebsiella pneumoniae by directly applying bacterial colonies without further protein extraction. A total of 40 K. pneumoniae and 114 other related microorganisms isolated clinically were analyzed by SELDI-TOF MS. An identification model for K. pneumoniae was established by artificial neural networks (ANNs) with classification accuracy of 100%. The model was blindly tested with 43 K. pneumoniae and 53 control bacteria again. The results showed that the model was successful with accuracy of 96.9%, sensitivity of 100% and specificity of 94.3%. This strategy is potential for rapid identification of K. pneumoniae.

Biotechnologies for Improving Animal Metabolism and Growth - A Review

Chen, Daiwen Asian Australasian Association of Animal Productio 2001 Animal Bioscience Vol.14 No.12

Biotechnology will play critical role in improving animal productivity. Animal growth rate and muscle deposition potential can be greatly improved by the application of biotechnology and biotechnological products. Administration of recombinant somatotropin (ST) or other compounds such as IGF-1 and growth hormone-releasing peptides (GHRPs) can enhance growth rate and carcass lean percentage. Gene transfer offers a powerful approach to manipulate endocrine system and metabolic pathways toward faster growth and better feed efficiency. Biotechnology is also extensively used for improving metabolism and activity of gut microorganisms for better nutrient digestibility. Knockout of growth-inhibiting genes such as myostatin results in considerable acceleration of body weight and muscle growth. Animal growth can also be improved by the use of gene therapy. Immunomodulation is another approach for efficient growth through controlling the activity of endogenous anabolic hormones. All the above aspects will be discussed in this review.

Environmental Challenges of Animal Agriculture and the Role and Task of Animal Nutrition in Environmental Protection - Review -

Chen, Daiwen Asian Australasian Association of Animal Productio 2001 Animal Bioscience Vol.14 No.3

Animals are one of the important memberships of the food chain. The low-efficiency rule of nutrient transfer from one member to the next in the food chain determines the low efficiency of animal agriculture for human food. On the average, about 20% feed proteins and 15% feed energy can be converted into edible nutrients for humans. The rest proportion of feed nutrients is exposed to the environment. Environmental pollution, therefore, is inevitable as animal agriculture grows intensively and extensively. The over-loading of the environment by nutrients such as nitrogen, phosphorus from animal manure results in soil and water spoilage. The emission of gases like $CH_2$, $CO_2$, $SO_2$, NO, $NO_2$ by animals are one of the contributors for the acidification of the environment and global warming. The inefficient utilization of natural resources and the probable unsafety of animal products to human health are also a critical environmental issue. Improving the conversion efficiency of nutrients in the food chain is the fundamental strategy for solving environmental issues. Specifically in animal agriculture, the strategy includes the improvements of animal genotypes, nutritional and feeding management, animal health, housing systems and waste disposal programs. Animal nutrition science plays a unique and irreplaceable role in the control of nutrient input and output in either products or wastes. Several nutritional methods are proved to be effective in alleviating environmental pollution. A lot of nutritional issues, however, remain to be further researched for the science of animal nutrition to be a strong helper for sustainability of animal agriculture.

Gene Therapy for Bovine Fatty Liver : Possibilities and Problems - A Review

Chen, Daiwen,Grummer, Ric Asian Australasian Association of Animal Productio 2001 Animal Bioscience Vol.14 No.9

Dairy cows are prone to fatty liver during the time of periparturient. Despite of the extensive studies, etiology and solutions for fatty liver are still not well known.The liver synthesizes triglycerides (TG) using precursors from bloodstream and secretes TG in form of very low density lipoprotein (VLDL) into bloodstream for the utilization by peripheral tissues. When the amount of TG synthesis exceeds the amount of secretion in VLDL-TG, TG accumulation within the liver occurs. Hepatic VLDL assembly and secretion involve multi-biochemical events.The availabilities of apolipoprotein B (apoB), E (apoE), microsomal triglyceride transfer protein (MTP) and soluble low density lipoprotein (LDL) receptor are now believed to be some of the main regulators for hepatic VLDL assembly and secretion. Studies in transgenic animals show that overexpression of these proteins stimulates VLDL production and secretion, which provides a possibility for alleviating bovine fatty liver by gene therapy. However, many problems remain to be solved to attain this goal. This review focuses on the molecular mechanisms of hepatic VLDL assembly and secretion, and the possibilities and problems of applying the knowledges to solve bovine fatty liver by gene therapy.

Leucine Protects Against Skeletal Muscle Atrophy in Lipopolysaccharide-Challenged Rats

Jin Wan,Daiwen Chen,Bing Yu,Yuheng Luo,Xiangbing Mao,Ping Zheng,Jie Yu,Junqiu Luo,Jun He 한국식품영양과학회 2017 Journal of medicinal food Vol.20 No.1

Skeletal muscle atrophy is a decrease in muscle mass that occurs when protein degradation exceeds protein synthesis. Leucine (Leu), an essential branched-chain amino acid in animal nutrition, regulates skeletal muscle protein metabolism. Two experiments were conducted to evaluate whether Leu could alleviate lipopolysaccharide (LPS)-induced skeletal muscle wasting by modulating skeletal muscle protein synthesis and degradation. A total of 24 rats were randomly allocated into three groups (n = 8): (1) non-challenged control; (2) LPS-challenged control; and (3) LPS +3.0% Leu. Rats were fed with control or Leu-supplemented (part of the casein was replaced with 3.0% Leu) diets throughout the trial and were injected intraperitoneally with sterile saline or LPS at days 6, 11, 16, and 21. On the morning of day 22, serum samples were collected and rats were then sacrificed for liver and muscle analysis. In vitro protein degradation, nuclear factor-κB (NF-κB) activity, and proteolytic enzyme activities of the muscles from immune-challenged rats were also measured. Our results showed that the LPS challenge resulted in not only enhanced serum interleukin-1 and liver C-reactive protein (CRP) concentrations but also decreased the average daily body weight gain and muscle fiber diameter. However, dietary Leu inclusion attenuated the increase in CRP level and the decrease in muscle fiber diameter. Importantly, the LPS challenge caused a significant elevation in the muscle proteolysis rate, but dietary Leu supplementation significantly blocked the muscle proteolysis. The mRNA expression of NF-κB, muscle atrophy F-box (MAFbx), and muscle ring finger 1 (MuRF1) was upregulated by the LPS challenge in gastrocnemius muscles, but was downregulated by Leu supplementation. Interestingly, when muscles from the LPS-challenged rats were incubated with Leu in vitro, proteasome-, calpain-, and cathepsin-L-dependent muscle proteolysis and NF-κB activity were decreased. Collectively, the data suggest that Leu supplementation could inhibit excessive skeletal muscle degradation, as well as enhance protein synthesis and, thus, attenuate the negative effects caused by the LPS-induced immune challenge.

Bioactive Compounds / Food Microbiology : Expression of a Tandemly Arrayed Plectasin Gene from Pseudoplectania nigrella in Pichia pastoris and its Antimicrobial Activity

( Jin Wan ),( Yan Li ),( Daiwen Chen ),( Bing Yu ),( Ping Zheng ),( Xiangbing Mao ),( Jie Yu ),( Jun He ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.3

In recent years, various naturally occurring defence peptides such as plectasin have attracted considerable research interest because they could serve as alternatives to antibiotics. However, the production of plectasin from natural microorganisms is still not commercially feasible because of its low expression levels and weak stability. A tandemly arrayed plectasin gene (1,002 bp) from Pseudoplectania nigrella was generated using the isoschizomer construction method, and was inserted into the pPICZαA vector and expressed in Pichia pastoris. The selected P. pastoris strain yielded 143 μg/ml recombinant plectasin (Ple) under the control of the methanol-inducible alcohol oxidase 1 (AOX1) promoter. Ple was estimated by SDS-PAGE to be 41 kDa. In vitro studies have shown that Ple efficiently inhibited the growth of several gram-positive bacteria such as Streptococcus suis and Staphylococcus aureus. S. suis is the most sensitive bacterial species to Ple, with a minimum inhibitory concentration (MIC) of 4 μg/ml. Importantly, Ple exhibited resistance to pepsin but it was quite sensitive to trypsin and maintained antimicrobial activity over a wide pH range (pH 2.0 to 10.0). P. pastoris offers an attractive system for the cost-effective production of Ple. The antimicrobial activity of Ple suggested that it could be a potential alternative to antibiotics against S. suis and S. aureus infections.

Effects of Oxidative Stress Induced by Diquat on Arginine Metabolism of Postweaning Pigs

Zheng, Ping,Yu, Bing,Lv, Mei,Chen, Daiwen Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.1

A total of 16 crossbred post-weaning pigs (10.64${\pm}$0.27 kg BW) were individually penned and assigned to one of two treatments to investigate the influences of diquat-induced oxidative stress on performance and arginine metabolism. Pigs in the oxidative stress group were injected intra-peritoneally with 10 mg/kg BW of diquat, while the control group were injected with isotonic saline. All pigs were fed ad libitum. The experiment lasted for 7 days. The results indicated that compared with control treatment, oxidative stress induced by diquat significantly decreased average daily gain, intake and feed conversion. The treatment decreased activities of antioxidant enzymes, increased concentration of malondialdehyde in plasma, increased cationic amino acid transporter-1 mRNA level and activity of ornithine aminotransferase and concentrations of arginine and citrulline in the jejunum, decreased the concentrations of arginine in plasma and kidney, and decreased induced nitric oxide synthase mRNA level. It is concluded that oxidative stress induced by diquat can influence absorption and metabolism of arginine and consequently modify the requirement of arginine for post-weaning pigs.

Effects of Benzoic Acid and Thymol on Growth Performance and Gut Characteristics of Weaned Piglets

Hui Diao,Ping Zheng,Bing Yu,Jun He,Xiangbing Mao,Jie Yu,Daiwen Chen 아세아·태평양축산학회 2015 Animal Bioscience Vol.28 No.6

A total of 144 weaned crossed pigs were used in a 42-d trial to explore the effects of different concentrations/ combinations of benzoic acid and thymol on growth performance and gut characteristics in weaned pigs. Pigs were randomly allotted to 4 dietary treatments: i) control (C), basal diet, ii) C+1,000 mg/kg benzoic acid+100 mg/kg thymol (BT1), iii) C+1,000 mg/kg benzoic acid+200 mg/kg thymol (BT2) and, iv) C+2,000 mg/kg benzoic acid+100 mg/kg thymol (BT3). Relative to the control, pigs fed diet BT3 had lower diarrhoea score during the overall period (p<0.10) and improved feed to gain ratio between days 1 to 14 (p<0.05), which was accompanied by improved apparent total tract digestibility of ether extract, Ca and crude ash (p<0.05), and larger lipase, lactase and sucrose activities in the jejunum (p<0.05) at d 14 and d 42. Similarly, relative to the control, pigs fed diet BT3 had higher counts for Lactobacillus spp in digesta of ileum at d 14 (p<0.05), and pigs fed diets BT1, BT2, or BT3 also had higher counts of Bacillus spp in digesta of caecum at d 14 (p<0.05), and lower concentration of ammonia nitrogen in digesta of caecum at d 14 and d 42 (p<0.05). Finally, pigs fed diet BT3 had higher concentration of butyric acid in digesta of caecum at d 42 (p<0.05), and a larger villus height:crypt depth ratio in jejunum and ileum at d 14 (p<0.05) than pigs fed the control diet. In conclusion, piglets fed diet supplementation with different concentrations/combinations of benzoic acid and thymol could improve feed efficiency and diarrhoea, and improve gut microfloral composition. The combination of 2,000 mg/kg benzoic acid+100 mg/kg thymol produced better effects than other treatments in most measurements.

Paradigm of Time-sequence Development of the Intestine of Suckling Piglets with Microarray

Sun, Yunzi,Yu, Bing,Zhang, Keying,Chen, Xijian,Chen, Daiwen Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.10

The interaction of the genes involved in intestinal development is the molecular basis of the regulatory mechanisms of intestinal development. The objective of this study was to identify the significant pathways and key genes that regulate intestinal development in Landrace piglets, and elucidate their rules of operation. The differential expression of genes related to intestinal development during suckling time was investigated using a porcine genome array. Time sequence profiles were analyzed for the differentially expressed genes to obtain significant expression profiles. Subsequently, the most significant profiles were assayed using Gene Ontology categories, pathway analysis, network analysis, and analysis of gene co-expression to unveil the main biological processes, the significant pathways, and the effective genes, respectively. In addition, quantitative real-time PCR was carried out to verify the reliability of the results of the analysis of the array. The results showed that more than 8000 differential expression transcripts were identified using microarray technology. Among the 30 significant obtained model profiles, profiles 66 and 13 were the most significant. Analysis of profiles 66 and 13 indicated that they were mainly involved in immunity, metabolism, and cell division or proliferation. Among the most effective genes in these two profiles, CN161469, which is similar to methylcrotonoyl-Coenzyme A carboxylase 2 (beta), and U89949.1, which encodes a folate binding protein, had a crucial influence on the co-expression network.

Effects of Benzoic Acid and Thymol on Growth Performance and Gut Characteristics of Weaned Piglets

Diao, Hui,Zheng, Ping,Yu, Bing,He, Jun,Mao, Xiangbing,Yu, Jie,Chen, Daiwen Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.6

A total of 144 weaned crossed pigs were used in a 42-d trial to explore the effects of different concentrations/combinations of benzoic acid and thymol on growth performance and gut characteristics in weaned pigs. Pigs were randomly allotted to 4 dietary treatments: i) control (C), basal diet, ii) C+1,000 mg/kg benzoic acid+100 mg/kg thymol (BT1), iii) C+1,000 mg/kg benzoic acid+200 mg/kg thymol (BT2) and, iv) C+2,000 mg/kg benzoic acid+100 mg/kg thymol (BT3). Relative to the control, pigs fed diet BT3 had lower diarrhoea score during the overall period (p<0.10) and improved feed to gain ratio between days 1 to 14 (p<0.05), which was accompanied by improved apparent total tract digestibility of ether extract, Ca and crude ash (p<0.05), and larger lipase, lactase and sucrose activities in the jejunum (p<0.05) at d 14 and d 42. Similarly, relative to the control, pigs fed diet BT3 had higher counts for Lactobacillus spp in digesta of ileum at d 14 (p<0.05), and pigs fed diets BT1, BT2, or BT3 also had higher counts of Bacillus spp in digesta of caecum at d 14 (p<0.05), and lower concentration of ammonia nitrogen in digesta of caecum at d 14 and d 42 (p<0.05). Finally, pigs fed diet BT3 had higher concentration of butyric acid in digesta of caecum at d 42 (p<0.05), and a larger villus height:crypt depth ratio in jejunum and ileum at d 14 (p<0.05) than pigs fed the control diet. In conclusion, piglets fed diet supplementation with different concentrations/combinations of benzoic acid and thymol could improve feed efficiency and diarrhoea, and improve gut microfloral composition. The combination of 2,000 mg/kg benzoic acid+100 mg/kg thymol produced better effects than other treatments in most measurements.