Endothelial deletion of PTBP1 disrupts ventricular chamber development

The growth and maturation of the ventricular chamber require spatiotemporally precise synergy between diverse cell types. Alternative splicing deeply affects the processes. However, the functional properties of alternative splicing in cardiac development are largely unknown. Our study reveals that an alternative splicing factor polypyrimidine tract-binding protein 1 (PTBP1) plays a key role in ventricular chamber morphogenesis. During heart development, PTBP1 colocalizes with endothelial cells but is almost undetectable in cardiomyocytes. The endothelial-specific knockout of Ptbp1, in either endocardial cells or pan-endothelial cells, leads to a typical phenotype of left ventricular noncompaction (LVNC). Mechanistically, the deletion of Ptbp1 reduces the migration of endothelial cells, disrupting cardiomyocyte proliferation and ultimately leading to the LVNC. Further study shows that Ptbp1 deficiency changes the alternative splicing of β-arrestin-1 (Arrb1), which affects endothelial cell migration. In conclusion, as an alternative splicing factor, PTBP1 is essential during ventricular chamber development, and its deficiency can lead to congenital heart disease.

The combined impact of xylo-oligosaccharides and gamma-irradiated astragalus polysaccharides on the immune response, antioxidant capacity and intestinal microbiota composition of broilers

The present study investigated the individual and combined effects of xylo-oligosaccharides (XOS) and gamma-irradiated astragalus polysaccharides (IAPS) on the immune response, antioxidant capacity and intestinal microbiota composition of broiler chickens. A total of 240 newly hatched Ross 308 chicks were randomly allocated into 5 dietary treatments including the basal diet (control), or the basal diet supplemented with 50 mg/kg chlortetracycline (CTC), 100 mg/kg XOS (XOS), 600 mg/kg IAPS (IAPS), and 100 mg/kg XOS + 600 mg/kg IAPS (XOS + IAPS) respectively. The results showed that birds in the control group had lower the thymus index and serum lysozyme activity than those in the other 4 groups (P < 0.05). Moreover, there was an interaction between XOS and IAPS treatments on increasing the serum lysozyme activity (P < 0.05). Birds in the CTC and XOS + IAPS groups had lower serum malondialdehyde concentration and higher serum total antioxidant capacity activity and mucosal interleukin 2 mRNA expression of jejunum than those in the control group (P < 0.05). In addition, birds in the control groups had lower duodenal and jejunal IgA-producing cells number than these in other 4 groups (P < 0.05). As compared with the CTC group, dietary individual XOS or IAPS administration increased duodenal IgA-producing cells number (P < 0.05). Meanwhile, there was an interaction between XOS and IAPS treatments on increasing duodenal and jejunal IgA-Producing cells numbers (P < 0.05). Dietary CTC administration increased the proportion of Bacteroides, and decreased the proportion of Negativibacillus (P < 0.05). However, dietary XOS + IAPS administration increased Firmicutes to Bacteroidetes ratio, the proportion of Ruminococcaceae, as well as decreased the proportion of Barnesiella and Negativibacillus (P < 0.05). In conclusion, the XOS and IAPS combination could improve intestinal mucosal immunity and barrier function of broilers by enhancing cytokine gene expression, IgA-producing cell production and modulates cecal microbiota, and the combination effect of XOS and IAPS is better than that of individual effect of CTC, XOS, or IAPS in the current study.

Creatine nitrate supplementation strengthens energy status and delays glycolysis of broiler muscle via inhibition of LKB1/AMPK pathway

This study aimed to evaluate the effects of dietary creatine nitrate (CrN) on growth performance, meat quality, energy status, glycolysis, and related gene expression of liver kinase B1/AMP-activated protein kinase (LKB1/AMPK) pathway in Pectoralis major (PM) muscle of broilers. A total of 240 male Arbor Acres broilers (28-day-old) were randomly allocated to one of 5 dietary treatments: the basal diet (control group), and the basal diets supplemented with 600 mg/kg guanidinoacetic acid (GAA), 300, 600, or 900 mg/kg CrN (identified as GAA₆₀₀, CrN₃₀₀, CrN₆₀₀, or CrN₉₀₀, respectively). We found that dietary GAA and CrN supplementation for 14 d from d 28 to 42 did not affect broiler growth performance, carcass traits, and textural characteristics of breast muscle. GAA₆₀₀, CrN₆₀₀, and CrN₉₀₀ treatments increased pH_24h and decreased drip loss of PM muscle compared with the control (P < 0.05). The PM muscles of CrN₆₀₀ and CrN₉₀₀ groups showed higher glycogen concentration and lower lactic acid concentration accompanied by lower activities of phosphofructokinase (PFK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) (P < 0.05). Simultaneously, GAA₆₀₀ and all CrN treatments increased concentration of muscle creatine, phosphocreatine (PCr) and ATP, and decreased AMP concentration and AMP/ATP ratio (P < 0.05). Meanwhile, the concentrations of muscle creatine, PCr, and ATP were increased linearly, while muscle AMP concentration and AMP/ATP ratio were decreased linearly and quadratic as the dose of CrN increased (P < 0.05). GAA₆₀₀, CrN₆₀₀, and CrN₉₀₀ treatments upregulated mRNA expression of CreaT in PM muscle, and CrN₆₀₀ and CrN₉₀₀ treatments downregulated GAMT expression in liver and PM muscle compared with the control or GAA₆₀₀ groups (P < 0.05). The mRNA expression of muscle LKB1, AMPKα1, and AMPKα2 was downregulated linearly in response to the increasing CrN level (P < 0.05). Overall, CrN showed better efficacy on strengthening muscle energy status and improve meat quality than GAA at the some dose. These results indicate that CrN may be a potential replacement for GAA as a new creatine supplement.

The combined impact of xylo-oligosaccharides and gamma-irradiated Astragalus polysaccharides on growth performance and intestinal mucosal barrier function of broilers

This study was conducted to investigate the individual and combined effects of xylo-oligosaccharides (XOS) and gamma-irradiated Astragalus polysaccharides (IAPS) on the growth performance and intestinal mucosal barrier function of broiler chickens. A total of 240 1-day-old Ross-308 chicks were allocated into 5 groups for 21 d: control group (basal diet), antibiotic growth promoter (AGP) group (basal diet supplemented with 50 mg/kg chlortetracycline), XOS group (basal diet supplemented with 100 mg/kg XOS), IAPS group (basal diet supplemented with 600 mg/kg IAPS), and XOS + IAPS group (basal diet supplemented with 100 mg/kg XOS and 600 mg/kg IAPS). The results showed that birds in the XOS + IAPS group showed higher ADG and lower feed-to-gain ratio than those in the control group (P < 0.05). The XOS, IAPS, and XOS + IASP treatments significantly increased villus height (VH) of all intestine segments, jejunal goblet cell numbers, and VH–to–crypt depth ratio (VH/CD) of broilers than those of the control group (P < 0.05). Birds in the XOS + IAPS group had higher jejunal VH/CD ratio and goblet cell numbers than those from the XOS or IAPS groups (P < 0.05). In addition, there was a synergy effect between XOS and IAPS on increasing duodenal goblet cell numbers and improving ileal morphology (higher VH and VH/CD ratio) (P < 0.05). The XOS, IAPS and XOS + IAPS treatments increased the mRNA expression of zonula occludens-1 and occludin of the jejunum as compared with the control group (P < 0.05). Simultaneously, birds in the XOS + IAPS group showed lower plasma D-lactic acid concentration and higher mRNA expression of claudin-1, claudin-3, and occludin in the jejunum than those in the control or IAPS groups (P < 0.05). Moreover, there was no significant difference in growth performance, intestinal morphology, and intestinal barrier function of broilers between the AGP and XOS + IAPS groups. In conclusion, the combination of XOS and IAPS had a better potential as chlortetracycline substitute for improving the growth performance, intestinal morphology, and intestinal barrier function of broilers.

Enhanced transforming growth factor-beta signaling and fibrosis in the pectoralis major muscle of broiler chickens affected by wooden breast myopathy

Fibrosis has also been recorded as a prominent pathological feature within wooden breast (WB) myopathy of broiler chickens. This study was conducted to evaluate the accumulation of fibril collagen, deposition of the extracellular matrix (ECM) components, and the underlying mechanism mediating the pathogenic fibrotic process in the pectoralis major (PM) muscle of WB-affected birds. Broiler chickens were categorized into the control and WB groups based on the evaluation of myopathic lesions. Results indicated that the total content and area of collagen in cross-sections of the PM muscle, as well as the augmented expression of collagen-I and fibronectin in the ECM, were greatly increased in birds with WB. Wooden breast myopathy upregulated expressions of transforming growth factor-beta (TGF-β) and the phosphorylation of Smad 2 and 3, thereby activating TGF-β-mediated Smad signaling pathway, which further enhanced the transcription of profibrotic mediators. In addition, regulators involved in collagen biosynthesis and cross-linking including prolyl 4-hydroxylase, lysyl oxidase, lysyl hydroxylase, and decorin were increased in the WB muscle. Finally, the expressions of both matrix metalloproteinases (MMP) and tissue inhibitor of metalloproteinases (TIMP) were increased in the WB muscle, which might be related with reduced ECM remodeling. Overall, WB myopathy induces severe fibrosis by enhancing ECM deposition and collagen cross-linking in the PM muscle of broiler chickens, possibly via the activation of TGF-β signaling and the dysregulation of the MMP and TIMP system.

Microbiota populations and short-chain fatty acids production in cecum of immunosuppressed broilers consuming diets containing γ-irradiated Astragalus polysaccharides

This study was designed to evaluate the effects of γ-irradiated Astragalus polysaccharides (IAPS) on growth performance, cecal microbiota populations, and concentrations of cecal short-chain fatty acids of immunosuppressed broilers. A total of 144 one-day-old broiler chicks were randomly assigned into 3 groups: nontreated group (control), cyclophosphamide (CPM)-treated groups fed either a basal diet or the diets containing 900 mg/kg IAPS, respectively. On day 16, 18, and 20, broilers in the control group were intramuscularly injected with 0.5 mL sterilized saline (0.75%, wt/vol), and those in the CPM and IAPS groups were intramuscularly injected with 0.5 mL CPM (40 mg/kg of BW). The trial lasted 21 d. Compared with the control group, CPM treatment decreased the broiler average daily gain (ADG) and feed intake (P < 0.05) but did not affect the overall microbial diversity and compositions, as well as the concentrations of cecal acetate, propionate, and butyrate in cecum of broilers (P > 0.05). Dietary IAPS supplementation increased broiler ADG, Shannon index, and decreased Simpson index (P < 0.05). Specifically, broilers fed diets containing IAPS showed lower abundances of Faecalibacterium, Bacteroides, and Butyricicoccus and higher proportions of Ruminococcaceae UCG-014, Negativibacillus, Shuttleworthia, Sellimonas, and Mollicutes RF39_norank, respectively (P < 0.05). The IAPS treatment also increased butyrate concentration (P < 0.05) and tended to elevate acetate concentration (P = 0.052) in cecal digesta. The results indicated that IAPS are effective in increasing the cecal beneficial bacteria and short-chain fatty acids production, contributing to improvement in the growth performance of immunosuppressive broilers. These findings may expand our knowledge about the function of modified Astragalus polysaccharides in broiler chickens.

Glucose and lipid metabolism of broiler chickens fed diets with graded levels of corn resistant starch

1. The aim of this study was to investigate the effects of graded levels of dietary corn resistant starch (RS) on glucose and lipid metabolism of broilers. 2. A total of 320 male broiler chicks (Arbor Acres, one-day-old) were randomly allocated to five dietary treatments, including a corn-soybean control diet, a corn-soybean based diet containing 20% corn starch, and three diets containing 4%, 8% and 12% RS by replacing corn starch with 6.67%, 13.33% and 20% Hi-Maize® 260 (identified as control, RS1, RS2, RS3 and RS4, respectively). Each treatment contained eight replicates with eight birds, and the experiment lasted 42 days. 3. Birds fed RS diets showed lower (P < 0.05) concentrations of serum low-density lipoprotein cholesterol and non-esterified fatty acid (NEFA) at d 21 and 42 of age, compared to the control. Lower (P < 0.05) hepatic apolipoprotein B concentration and citrate synthase (CS) activity, as well as a higher (P < 0.05) glycogen synthase (GS) concentration were observed in birds fed RS diets than those in the control group at d 21 of age. Consuming RS diets linearly increased (P < 0.01) serum glucose concentration, and linearly decreased (P < 0.01) NEFA concentrations in broilers at d 21 and 42 of age. Liver GS concentration and activities of hexokinase, pyruvate and CS were linearly increased (P < 0.01) in broilers at d 21 of age, but were linearly decreased (P < 0.05) in birds at d 42 of age in response to the increase of dietary RS levels. Feeding RS diets linearly decreased (P < 0.05) mRNA expressions of PC, PPARα and CPT-1 at d 21 of age and the mRNA expressions of SREBP-1 c, ChREBP, ACC and FAS at d 42 of age, and linearly increased (P < 0.05) the mRNA expressions of PEPCK, PC, LKB1, AMPKα1, PPARα, CPT-1 and L-FABP at d 42 of age. 4. Feeding broilers with diets containing higher concentration of RS promoted hepatic lipolysis and gluconeogenesis through activated AMPK signalling pathway and accelerated whole-body energy expenditures in the grower phase.

Dynamics and bifurcations in multistable 3-cell neural networks

We disclose the generality of the intrinsic mechanisms underlying multistability in reciprocally inhibitory 3-cell circuits composed of simplified, low-dimensional models of oscillatory neurons, as opposed to those of a detailed Hodgkin-Huxley type [Wojcik et al., PLoS One 9, e92918 (2014)]. The computational reduction to return maps for the phase-lags between neurons reveals a rich multiplicity of rhythmic patterns in such circuits. We perform a detailed bifurcation analysis to show how such rhythms can emerge, disappear, and gain or lose stability, as the parameters of the individual cells and the synapses are varied.

Protective effects of γ-irradiated Astragalus polysaccharides on intestinal development and mucosal immune function of immunosuppressed broilers

This study was aimed to assess the protective effects of γ-irradiated Astragalus polysaccharides (IAPS) on the development of small intestine and intestinal mucosal immunity of immunosuppressed broilers induced by cyclophosphamide (CPM). A total of 384 one-day-old broiler chicks with similar initial weight were randomly assigned into 6 groups: non-treated group (control), and CPM-treated groups fed either a basal diet or the diets containing 900 mg/kg APS, or 900, 600, 300 mg/kg IAPS, respectively. On days 16, 18, and 20, all broilers except for control group were intramuscularly injected with 0.5 mL CPM (40 mg/kg of BW). Broilers in the control group were intramuscularly injected with 0.5 mL sterilized saline (0.75%, wt/vol). This trial was lasted for 21 d. The results revealed that both APS and IAPS treatment elevated the duodenal IgA-producing cells number and the jejunal mRNA expression of interleukin-2 (IL-2), interleukin-10 (IL-10), and interferon γ of CPM-injected broilers (P < 0.05). The decreased jejunal villus height (VH), the ratio of VH to crypt depth (V/C), as well as the intestinal intraepithelial lymphocytes (IELs) and goblet cells number in CPM-injected broilers were elevated by dietary supplementation with 900 mg/kg APS or 900, 600 mg/kg IAPS (P < 0.05). The CPM-induced decrease in jejunum index, the duodenal VH and the jejunal IgA-producing cells number were only improved in the 900 mg/kg IAPS group (P < 0.05). Furthermore, the number of IELs and IgA-producing cells in duodenum, VH, V/C, the number of goblet cells, and mRNA expression of IL-2 and IL-10 in jejunum were higher in the 900 mg/kg IAPS group than those in the 900 mg/kg APS group (P < 0.05). In summary, IAPS possessed stronger immunomodulatory effect than APS at the same supplementation level. Therefore, gamma irradiation can be used as an alternative treatment to enhance the immunomodulatory activity of APS.

Characteristics and incidence of broiler chicken wooden breast meat under commercial conditions in China

Wooden breast (WB) has emerged as a dramatically increasing myopathy in the poultry industry over the past few years. The objective of this study was to investigate the incidence of WB in a Chinese commercial broiler processing plant, and the consequences on quality attributes, textural properties, and sensory traits. A total of 1,135 breast fillets were collected at the deboning line and assigned to normal, mild, moderate, and severe WB categories by tactile evaluation. The proportion affected by WB was approximately 61.9%. WB fillets appeared heavier and thicker than normal fillets. The degree of WB myopathy was highly correlated with fillet weight and thickness. The meat quality characteristics of cooking loss and purge loss increased along with increasing severity of WB myopathy. Compression tests of raw meat revealed higher cutting strength and shear values for WB. In cooked meat, only severe WB fillets exhibited elevated hardness and chewiness. Finally, moderate and severe WB fillets affected the sensory evaluation by consumers owing to their impaired general appearance, texture, and drip loss. The results suggested that a high proportion of WB broiler fillets would cause detrimental losses to the poultry meat retailing and processing industry.

Growth performance, carcass traits and digestive function of broiler chickens fed diets with graded levels of corn resistant starch

1. This study was conducted to assess the effects of graded levels of dietary corn resistant starch (RS) on growth performance, carcass traits, nutrient retention, digestive organ index, intestinal morphology, digestive enzyme activities, and mRNA expression of certain nutrient transporters in broiler chickens.2. A total of 320, 1-d-old Arbor Acres broiler chickens were randomly assigned to five dietary treatments, with eight replicates of eight birds in each. These treatments included one corn-soybean control diet, a corn-soybean based diet containing 20% corn starch, and three diets supplemented with 4%, 8% and 12% RS by replacing corn starch with 6.67%, 13.33% and 20% of Hi-Maize 260® (identified as control, RS1, RS2, RS3 and RS4, respectively). The feeding period lasted 42 days.3. Performance parameters including feed consumption, feed conversion, body weight gain and percentage of abdominal fat at d 42 of age, nutrient retention (including dry matter, fat, total starch and nitrogen free extract), and apparent metabolisable energy was measured from d 18 to 20 and d 39 to 41 and showed negative linear responses to increasing dietary RS level (P < 0.05). Birds fed the RS3 and RS4 diets showed higher relative weight of duodenum, jejunum and ileum, as well as lower villus height and villus height/crypt depth compared to the control (P < 0.05). The activity of pancreatic trypsin of birds at d 21 and 42 of age decreased linearly in response to the increase of dietary RS level (P < 0.01). There were linear changes in up-regulated mRNA expression of SGLT-1 and down-regulated mRNA expression of GLUT-2 with increasing proportion of RS at d 21 and 42 of age (P < 0.05), respectively.4. It was concluded that feeding broilers with diets containing higher concentrations of RS impaired the development of small intestine, which resulted in lower apparent total tract retention of nutrients and poorer body weight gain, feed efficiency and carcass traits of broiler chickens.

Dietary taurine supplementation enhances antioxidative capacity and improves breast meat quality of broiler chickens

1. The aim of this study was to determine the effect of dietary taurine supplementation on growth performance, meat quality and antioxidant responses in breast muscle of broiler chickens.2. A total of 72 Arbor Acres broiler chickens (28-day-old) with similar body weight were randomly allocated into two groups, and fed either 0 g/kg (control; C) or 5 g/kg taurine-supplemented diets (TS) for 14 days.3. The results showed that TS had no effect on growth performance or chemical composition of breast muscle in broilers. The drip and cooking losses were significantly decreased (P < 0.05), and the pH_24h of breast muscle were increased (P < 0.05) in the TS group. Meanwhile, broilers in the TS group exhibited significantly higher (P < 0.05) scavenging activities of superoxide and 2,2-diphenyl-1-picrylhydrazyl radicals, and lower (P < 0.05) contents of carbonyl, malondialdehyde, and 4-hydroxynonenal. TS increased (P < 0.05) total antioxidant capacity and superoxide dismutase activities. Moreover, TS significantly upregulated (P < 0.05) the mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1, NAD(P)H quinone dehydrogenase 1, superoxide dismutase, catalase, and glutathione peroxidase.4. These findings suggested that TS enhanced antioxidative capacity and improved breast meat quality of broilers via activating the Nrf2 pathway.

Different oxidative status and expression of calcium channel components in stress-induced dysfunctional chicken muscle

The objective of this study was to assess the effects of transport stress at high ambient temperatures on the oxidation status and the expression of essential elements responsible for the Ca transport (sarco- (endo-) plasmic reticulum Ca-ATPase (SERCA1) and the ryanodine receptor (RyR) in (PM) muscles of broilers. Briefly, Arbor Acres broiler chickens ( = 112) were randomly categorized into 2 treatments: unstressed control (C) and 0.5 h transport (T). Each treatment consisted of 8 replicates of 7 birds each. Birds were transported according to a designed protocol. PM muscle samples in T group were collected and classified as normal (T-NOR) or pale, soft, and exudative-like (T-PSE) using meat quality parameters. The results indicated that production of corticosterone (CORT) and reactive oxygen species (ROS) increased significantly after transportation ( < 0.05). Thiobarbituric acid reactive substance values and carbonyl contents increased significantly in the T group ( < 0.05). Moreover, the extent of lipid peroxidation and protein oxidation was more severe in the T-PSE group compared to the T-NOR group ( < 0.05). The mRNA and protein expression of SERCA1 and αRyR increased in the T-NOR group but decreased significantly in the T-PSE group compared to the CON group ( < 0.05). The mRNA expression of βRyR was found to be enhanced in the T-NOR group compared to the CON group, whereas there was no difference in the T-PSE group ( < 0.05). The results indicate that short-distance transport of broilers affects their physiological responses and biochemical changes which may lead to different oxidative states and, importantly, to different expressions of SERCA and RyR. These induced changes in abnormal sarcoplasmic Ca homeostasis have significant implications for the development of PSE-like meat.

Identifying the location of epidermal growth factor-responsive element involved in the regulation of type IIb sodium-phosphate cotransporter expression in porcine intestinal epithelial cells

Phosphate is an important mineral nutrient for both human and animals in growth and physiological functions; thus, much effort in the past has been made to clarify the mechanisms governing its absorption. Previous studies have found that epidermal growth factor (EGF) inhibits phosphate absorption in human intestinal cells via modulating the interaction of transcriptional factor c-myb with sodium-phosphate cotransporter (NaPi-IIb) gene promoter. This finding provoked our interest in determining the effect of EGF on NaPi-IIb gene expression in intestinal cells of pigs and the location of EGF-responsive element in the gene promoter. Using quantitative PCR, it was observed that EGF significantly reduced NaPi-IIb gene expression in porcine intestinal epithelial IPEC-J2 cells. Transfection with a series of constructs that contain different lengths of the 5'-flanking promoter region of the NaPi-IIb gene manifested that EGF-responsive element is located in the -1200 to -800 region. Further, c-myb was extracted from the cell nucleus of IPEC cells that were exposed to EGF or not via immunoprecipitation. The electrophoretic mobility shift assay showed a specific binding of transcription factor c-myb to labelled probes encompassing DNA sequence from -1092 to -1085 (-TCCAGTTG-). This protein-DNA complex was decreased with cells exposed to EGF and abrogated when c-myb was pre-incubated with excessive unlabelled competitive probes. Results from mutagenesis studies demonstrated that the c-myb-binding site is the EGF-responsive element involved in the regulation of NaPi-IIb expression. Identifying the location of EGF-responsive element contributes to understanding mechanisms underlying EGF down-regulated NaPi-IIb gene expression and provides a foundation for further investigating EGF-regulatory functions in phosphate absorption in pig intestine.

Effects of Water-misting Sprays with Forced Ventilation after Transport during Summer on Meat Quality, Stress Parameters, Glycolytic Potential and Microstructures of Muscle in Broilers

Effects of water-misting sprays with forced ventilation after transport during summer on meat quality, stress parameters, glycolytic potential and microstructures of muscle in broilers were investigated. A total of 105 mixed-sex Arbor Acres broilers were divided into three treatment groups: i) 45-min transport without rest (T group), ii) 45-min transport with 1-h rest (TR group), iii) 45-min transport with 15-min water-misting sprays with forced ventilation and 45-min rest (TWFR group). The results showed the TWFR group significantly increased (p<0.05) initial muscle pH (pHi) and ultimate pH (pHu) and significantly reduced L* (p<0.05), drip loss, cook loss, creatine kinase, lactate dehydrogenase activity, plasma glucose content, lactate and glycolytic potential when compared with other groups. Microstructure of the muscle from TWFR group broilers under light microscopy showed smaller intercellular spaces among muscle fibers and bundles compared with T group. In conclusion this study indicated water-misting sprays with forced ventilation after transport could relieve the stress caused by transport under high temperature, which was favorable for the broilers' welfare. Furthermore, water-misting sprays with forced ventilation after transport slowed down the postmortem glycolysis rate and inhibited the occurrence of PSE-like meat in broilers. Although rest after transport could also improve the meat quality, the effect was not as significant as water-misting sprays with forced ventilation after transport.

The effect of transportation of broilers during summer on the expression of heat shock protein 70, postmortem metabolism and meat quality

The objective of this study was to determine the effects of different transport times on broilers during summer on stress, meat quality, and early postmortem muscle metabolites. Arbor Acres broiler chickens (n = 105) were randomly categorized into 5 treatments: unstressed control, 0.5 h, 1 h, 2 h, and 4 h transport. Each treatment consisted of 3 replicates with 7 birds each. All birds (except the control group) were transported according to a designed protocol. With the extension of transport time, the activities of plasma creatine kinase (CK) and lactate dehydrogenase (LDH) gradually increased. The content of heat shock protein 70 (Hsp70) did not change significantly during 0.5 h transport compared to the control group, but was significantly higher (P < 0.05) at 1 h or more of transport time. Also, transport times of 2 h or more resulted in a death rate of 20%-33% of broilers. We found that the breast meat in the 0.5 h transport group had significantly (P < 0.05) higher L* values, drip loss, cooking loss, AMP/ATP ratio, and phosphorylation of AMP-activated protein kinase (p-AMPK). In addition, pH24h was lower compared to the control group, increasing the likelihood of pale, soft, and exudative (PSE)-like meat. However, no significant variations were found in meat color, drip loss, or cooking loss in other transport groups compared to the control group under the condition of this study. Muscle glycogen content decreased with time of transportation. There were significant correlations among p-AMPK and meat quality (P < 0.05). These results indicate that preslaughter transport during summer may cause severe physiological and biochemical changes of broilers. Further investigations studying the deeper relationship between biological indicators and meat quality according to the similar transport conditions would provide a better understanding of the effect of transport duration on meat quality.

Altered immune function of monocytes in different stages of patients with acute on chronic liver failure

The aim of this study was to investigate the characteristics of the immune function of monocytes in different stages of the patients with acute on chronic liver failure (ACLF). Human leucocyte antigen (HLA)-DR and Toll-like receptor 4 (TLR-4) expression on monocytes in early and late stages of acute on chronic liver failure were detected by flow cytometry. The secretion function of monocytes was measured by cytometric bead array. Compared with healthy controls, the levels of HLA-DR expression on monocytes in patients with chronic hepatitis B, liver cirrhosis and acute on chronic liver failure were gradually decreased, especially in the late stage of acute on chronic liver failure (P < 0.001). TLR-4 expression on monocytes in patients with liver cirrhosis and acute on chronic liver failure were higher than the healthy controls. The concentrations of interleukin (IL)-1beta, tumour necrosis factor (TNF)-alpha and IL-12p70 in early-stage ACLF were significantly higher compared with healthy controls and lower in late-stage ACLF (P < 0.01, 0.05). However, a significantly lower amount of IL-10 was found on monocytes in early-stage ACLF than that of late-stage ACLF and healthy controls (P < 0.01). Monocyte HLA-DR expression in patients who died was significantly lower compared with patients who survived in the early and late stages of ACLF (P < 0.01). The dynamic detection of HLA-DR expression or cytokines secreted from monocytes could contribute to the estimation of the status of the immune function of patients with acute on chronic liver failure.

Radiation responsiveness of human lung cancer cell lines measured with a short term semiautomatic assay

BACKGROUND

Fluorometric microculture cytotoxicity assay (FMCA) is a short-term semi-automatic method, based on dye-inclusion of surviving cells. The assay was developed for investigations of drug resistance on tumour cells from biopsy material. In the present study, this short-term assay was evaluated, regarding usefulness in determining radio-sensitivity.

MATERIALS AND METHODS

Eight human lung cancer cell lines were used. There were five small cell lung cancer (SCLC and three non-small cell lung cancer (NSCLC cell lines. Results were compared with the corresponding data derived from the clonogenic assay and/or the extrapolation method.

RESULTS

The surviving fraction (SF) after 2, 5 and 10 Gy compared with data from the clonogenic assay were not in accordance for 5 of the 8 cell lines. The FMCA assay overestimated SF- values for the SCLC cell lines.

CONCLUSION

The FMCA assay is not useful as a quick screening method for the radioresponsiveness in vitro of human tumour cell lines.

Ectopic expression of an Arabidopsis calmodulin-like domain protein kinase-enhanced NADPH oxidase activity and oxidative burst in tomato protoplasts

Among plant defense responses to pathogen attack, the release of active oxygen species (AOS), termed the oxidative burst, may affect the attacking pathogen and the host plant cells at the infection site, thereby limiting the spread of the pathogen. Plasma membrane-associated NADPH oxidase represents a key enzyme in mediating the oxidative burst. The mechanisms of NADPH oxidase activation, however, remains unclear. Ectopic expression of AK1-6H, an Arabidopsis calmodulin-like domain protein kinase (CDPK) in tomato protoplasts enhanced plasma membrane-associated NADPH oxidase activity. Arabidopsis protein phosphatase 2A abolished this enhancement, whereas Arabidopsis dual-specificity protein tyrosine phosphatase 1 or maize protein phosphatase 1 had no effect tMEK2MUT, a constitutively activated, mitogen-activated protein kinase kinase from tomato, did not enhance NADPH oxidase activity when overexpressed. In a cell-free system, AK1-6H moderately stimulated the NADPH oxidase activity on plasma membrane. AK1-6H, but not tMEK2MUT, also enhanced production of AOS in intact protoplasts. Our results show that ectopic expression of a heterologous CDPK can enhance NADPH oxidase activity and stimulate an oxidative burst in tomato protoplasts.

Th1/Th2 type cytokines in hepatitis B patients treated with interferon-alpha

OBJECTIVE

To investigate the relationship between the expression of Th1/Th2 type cytokines and the effect of interferon-alpha therapy.

METHODS

Th1/Th2 type cytokines were assayed by enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR) on 23 patients with chronic hepatitis B who were treated with interferon-alpha.

RESULTS

Levels of IFN-gamma in the supernatant of peripheral blood mononuclear cells (PBMC) cultures from the patients with hepatitis B were slightly lower than those of controls (P = 0.07). However, the levels of IL-4 were higher than those of controls (P = 0.01). Cytokines measurements during IFN-alpha treatment showed a trend to decreasing levels of IL-4 at 4, 12, and 24 weeks. Levels of IFN-gamma were slightly increased following IFN-alpha treatment (P = 0.09). In patients with a complete response to IFN-alpha, the levels of IFN-gamma were higher at 24 weeks following IFN-alpha treatment than that of pre-treatment (P = 0.04), and the levels of IL-4 decreased markedly at 12 and 24 weeks (P = 0.02, 0.03, respectively). mRNA expression positively correlated with the level of Th1/Th2 type cytokines in the supernatant.

CONCLUSION

The expression of Th2 type cytokines is predominant in patients with chronic hepatitis B. Interferon-alpha therapy can modulate the balance of Th1/Th2 type cytokines, and this is related to its clinical effect. Levels of Th1/Th2 type cytokines could be a predictor of clinical response during Interferon-alpha treatment.

Activation of tomato PR and wound-related genes by a mutagenized tomato MAP kinase kinase through divergent pathways

A mitogen-activated protein kinase kinase (MAPKK) gene, tMEK2, was isolated from tomato cv. Bonny Best. By mutagenesis, a permanently active variant, tMEK2MUT, was created. Both wild-type tMEK2 and mutant tMEK2MUT were driven by a newly described strong plant constitutive promoter, tCUP, in a tomato protoplast transient gene expression system. Pathogenesis-related genes, PRlb1, PR3 and Twi1, and a wound-inducible gene, ER5, were activated by tMEK2MUT. Specific inhibitors of p38 class MAPK inhibited tMEK2MUT-induced activation of PR3 and ER5 genes but not that of the PRlb1 or Twi1 gene. Arabidopsis dual-specificity protein tyrosine phosphatase 1 (DsPTP1) and maize protein phosphatase 1 (PP1) inhibited tMEK2MUT-induced activation of the ER5 gene and the Twi1 gene, respectively, whereas PRlb1 and PR3 were not affected by either AtDsPTP1, or maize PP1, or Arabidopsis protein phosphatase 2A (PP2A). We have demonstrated for the first time that a single MAPKK activates an array of PR and wound-related genes. Our observation indicates that the activation of the genes downstream of tMEK2 occurs through divergent pathways and that tMEK2 may play an important role in the interaction of signal transduction pathways that mediate responses to both biotic (e.g. disease) and abiotic stresses (e.g. wound responsiveness).

In vitro PET evaluations in lung cancer cell lines

One purpose of the study was to explore the PET tracer 11C-L-DOPA for the discrimination between small-cell lung cancer (SCLC) and non small-cell lung cancer (NSCLC). A further aim was to explore the potential antitumoral effects of 6-diazo-5-oxy-L-norleucine (DON) and the use of a PET proliferation marker for the evaluation.

MATERIALS AND METHODS

Four lung cancer and one endocrine tumour cell line (BON) were cultured as monolayer. The uptake of 5-[76Br]-bromo-2-fluoro-deoxyuridine (76Br-BFU), [11C]-L-DOPA (11C-DOPA) and [18F]-fluorodeoxyglucose (18FDG) were evaluated. The effects of specific enzyme inhibitors affecting the DOPA metabolism were explored. The effect of DON on proliferation and uptake of 76Br-BFU were assessed.

RESULTS

All cell types showed a measurable uptake of 11C-DORA, with slightly lower values in lung cancer. There were no clear differences between SCLC and NSCLC. The addition of COMT inhibitor induced a significantly increased uptake of the tracer in BON cells, but not in lung cancer cells. DON significantly reduced the proliferation in all cell lines. The 76Br-BFU uptake was reduced markedly in all cell lines during DOn treatment.

CONCLUSION

11C-DOPA failed to distinguish between SCLC and NSCLC. DON showed strong antiproliferative effects which might motivate renewed interest in this drug for clinical cancer treatment. PET with 76Br-BFU might be used for treatment evaluation.

[Predictor of effect of interferon-alpha on patients with hepatitis B: Th1/Th2 type cytokines]

OBJECTIVE

To investigate the relationship between the expression of Th1/Th2 type cytokines and the effect of interferon-alpha therapy.

METHODS

Th1/Th2 type cytokines were detected by ELISA and RT-PCR in 23 patients with chronic hepatitis B who were treated with interferon-alpha for 24 weeks.

RESULTS

The levels of IFN-gamma in the supernatant of PBMC cultures of the patients with hepatitis B were slightly lower than those of the controls. However, the levels of IL-4 were higher in the patients than in the controls. Cytokines measurements during IFN-alpha treatment showed a trend toward decreased levels of IL-4 at 4, 12 and 24 weeks. However, the levels of IFN-gamma were slightly increased following IFN-alpha treatment. In patients with complete response to IFN-alpha, the levels of IFN-gamma were higher than that of pre-treatment at 24 weeks following IFN-alpha treatment, and the levels of IL-4 decreased obviously at 12 and 24 weeks. The mRNA levels of Th1/Th2 type cytokines were positively correlated with the levels of supernatant.

CONCLUSION

(1) The expression of Th2 type cytokines is predominant in patients with chronic hepatitis B. (2) The effect of interferon-alpha therapy may play a role in modulating the balance of Th1/Th2 type cytokines. (3) Variations of the levels of Th1/Th2 type cytokines could be used as a predictor of clinical response during interferon-alpha treatment.

[Expression of C-erbB-2 protein in breast cancer and its clinical significance]

In order to understand the expression of C-erbB-2 protein in breast cancer and its clinical significance, we examined the expression of C-erbB-2 protein in 106 breast carcinomas by using the immunohistochemical techniques LSAB. The results showed that the positive rate of C-erbB-2 expression was 63.21% (67/106). The overexpression of C-erbB-2 protein related negatively with survival. 81.63% of the cases with overexpression of C-erbB-2 protein survived < or = 5 years and 34.29% survived > 10 years. There were significant associations of C-erbB-2 overexpression with advanced clinical stage, high histological grade, and positive axillary node status in breast cancers. All of these findings suggested that overexpression of C-erbB-2 protein might be an important prognostic factor and the detection of C-erbB-2 protein might be arranged as a regular pathological examination in the cases of breast cancer.

[Expression of P62c-myc protein in breast cancer and its clinical significance]

The objective of this study was to determine the clinical significance of P62c-myc protein expression in breast cancer. P62c-myc protein was detected in 107 patients with breast cancer by immunohistochemical techniques (LSAB). The results showed that the positive rate of P62c-myc protein expression was 63.55% (68/107). The overexpression of P62c-myc protein related negatively with survival. 94.00% of the cases with overexpression of P62c-myc protein survived < or = 5 years, 65.00% survived > 5 years-< 10 years, and 21.62% survived > or = 10 years. There were significant associations of P62c-myc expression with advance clinical stage, high histological grade, and positive axillary node status in breast cancers. All of these findings suggested that overexpression of P62c-myc might be an important prognostic factor, and the detection of P62c-myc protein might be arranged as a regular pathological examination in the cases of breast cancer.

[Relationship of C-erbB-2 oncogene overexpression to estrogen progesterone receptors in brease cancer and its prognostic significance]

In order to understand the relationship of C-erbB-2 oncogene overexpression to ER and PR in breast cancer and its prognostic significance, we examined overexpression of C-erbB-2 oncogene in 106 breast carcinomas by using immunohistochemical techniques (LSAB). The results showed that the positive rate of C-erbB-2 overexpression was 63.21% (67/106). The overexpression of C-erbB-2 oncogene related negatively with survival. 81.63% of the cases with overexpression of C-erbB-2 oncogene survived < or = 5 years and 34.29% survived > 10 years. There were significant associations of C-erbB-2 overexpression with advance clinical stage, high histological grade, and positive axillary node status in breast cancers. Negative relationship between hormone receptors and C-erbB-2 oncogene. All of these findings suggested that overexpression of C-erbB-2 oncogene might be an important prognostic factor and the detection of C-erbB-2 oncogene might be arranged as a regular pathological examination in the cases of breast cancer.

[Clinical and pathological analysis of liver injury resulting from rifampin and isoniazid]

OBJECTIVE

To explore the relationship between clinical manifestations and pathological changes of liver injury resulting from rifampin and isoniazid.

METHOD

194 cases treated with rifampin and isoniazid, among them liver biopsies were done once in 28 cases, twice in 17 cases, were observed.

RESULTS

21 of 59 cases with positive HBVM and 13 out of 135 cases with negative HBVM showed abnormal liver function after treatment, and the elevation of ALT was in accordance with the degree of liver pathological injury. Elevated ALT and liver pathological injury returned to normal within 6 weeks after rifampin and isoniazid were stopped or reduced in doses. No significant difference was found between chronic hepatis B and rifampin, isoniazid in causing liver pathological injury, but two different points were noted in their manifestations: 1. The cells mainly caused portal inflammation were lymphocytes in the former, while eosinophils in the latter. 2. The incidence of intrahepatic cholestasis was higher in the latter.

CONCLUSION

The incidence of liver injury in HBVM positive group is higher than that in HBVM negative group because liver injury exists in the former before treatment, and the mechanisms causing liver injury may be different.

Race-specific elicitors of Cladosporium fulvum promote translocation of cytosolic components of NADPH oxidase to the plasma membrane of tomato cells

The effect of race-specific elicitors on NADPH oxidase was examined in vivo by treating tomato cells with elicitor-containing intercellular fluids prepared from infected tomato leaves inoculated with specific Cladosporium fulvum races. Treatment of Cf-4 or Cf-5 cells with intercellular fluids from incompatible but not from compatible races of C. fulvum increased oxidase activity and the amount of p67-phox, p47-phox, and rac2 in the plasma membrane. Comparison of these three components in the cytosol and plasma membrane indicated that elicitors promoted the translocation of cytosolic components of NADPH oxidase to the plasma membrane of tomato cells carrying the appropriate resistance gene. Protein kinase C activators and inhibitors did not affect enzyme activity or the binding of these three components to the plasma membrane. In contrast, staurosporine, calmodulin antagonists, and EGTA inhibited elicitor-induced oxidase activity and the translocation of the cytosolic components. The assembly process involves a Ca(2+)-dependent protein kinase that catalyzes the phosphorylation of p67-phox and p47-phox, facilitating their translocation to the plasma membrane. Our data suggest that although both plants and animals share common elements in eukaryotic signal transduction, the involvement of different protein kinases mediating the activation of phosphorylation of p67-phox and p47-phox may reflect the unique spatial and temporal distribution of signal transduction pathways in plants.

Regulation of Plant Defense Response to Fungal Pathogens: Two Types of Protein Kinases in the Reversible Phosphorylation of the Host Plasma Membrane H+-ATPase

The role of reversible phosphorylation of the host plasma membrane H+-ATPase in signal transduction during the incompatible interaction between tomato cells and the fungal pathogen Cladosporium fulvum was investigated. Tomato cells (with the Cf-5 resistance gene) or isolated plasma membranes from Cf-5 cells treated with elicitor preparations from race 2.3 or 4 of C. fulvum (containing the avr5 gene product) showed a marked dephosphorylation of plasma membrane H+-ATPase. Similar treatment with elicitor preparations from races 5 and 2.4.5.9.11 (lacking the avr5 gene product) showed no change in dephosphorylation. Elicitor (race 4) treatment of cells, but not of isolated plasma membranes, for 2 hr resulted in rephosphorylation of the ATPase via Ca2+-dependent protein kinases. The initial (first hour) rephosphorylation was enhanced by protein kinase C (PKC) activators and was prevented by PKC inhibitors. Activity of a second kinase appeared after 1 hr and was responsible for the continuing phosphorylation of the H+-ATPase. This latter Ca2+-dependent kinase was inhibited by a calmodulin (CaM) antagonist and by an inhibitor of Ca2+/CaM-dependent protein kinase II. The activation of the Ca2+/CaM-dependent protein kinase depended on the prior activation of the PKC-like kinase.

Investigation of the Calcium-Transporting ATPases at the Endoplasmic Reticulum and Plasma Membrane of Red Beet (Beta vulgaris)

Calcium-transporting ATPases were compared in endoplasmic reticulum (ER)- and plasma membrane-enriched fractions of red beet (Beta vulgaris L.) storage tissue by measuring 45Ca uptake and calcium-dependent phosphoenzyme formation. The plasma membrane fraction was prepared by aqueous two-phase partitioning of a microsomal fraction and collecting the upper phase. The ER-enriched fraction was obtained by submitting a sucrose-gradient ER-enriched fraction to aqueous two-phase partitioning and collecting the lower phase; this reduced contaminating plasma membrane, which partitioned into the upper phase. The ATP-dependent calcium uptake observed in both fractions was released by the calcium ionophore A23187. Calcium uptake showed saturation kinetics for calcium with Km values of 0.92 mmol m-3 for the ER fraction and 1.24 mmol m-3 for the plasma membrane fraction. Uptake into both fractions was inhibited by vanadate and erythrosin B, although the plasma membrane system was slightly more sensitive to both inhibitors. Cyclopiazonic acid and thapsigargin, at low concentrations, had no marked effect on uptake. The plasma membrane system was less substrate-specific for ATP than the ER system, since it was able to use GTP and ITP to drive calcium transport at up to 50% of the level obtained with ATP. Following phosphorylation with [[gamma]-32P]ATP, two high molecular mass, calcium-dependent phosphoproteins (119 and 124 kD) and a low molecular mass, calcium-independent phosphoprotein (17 kD) were observed in the plasma membrane fraction. The ER fraction showed one high molecular mass phosphoprotein (119 kD) in the presence of calcium and two low molecular mass phosphoproteins (17 and 20 kD) that showed no calcium dependence. The low molecular mass phosphoproteins were insensitive to hydroxyl-amine, but they did show turnover. The identity of these proteins is unknown, but they do not have the properties of phosphorylated intermediates of calcium-ATPases. In contrast, the high molecular mass phosphoproteins displayed properties consistent with their representing phosphorylated intermediates of E1E2-type ATPases; they were hydroxylamine-sensitive, showed rapid turnover, and were inhibited by vanadate. Because they showed calcium-dependent phosphorylation and were sensitive to erythrosin B, the 119- and 124-kD phosphoproteins may be phosphorylated intermediates of the ER and plasma membrane calcium ATPases. These phosphoproteins were characterized further with respect to inhibitor sensitivity, responses to ions, and substrate specificity.