β-carotene attenuates weaning-induced apoptosis via inhibition of PERK-CHOP and IRE1-JNK/p38 MAPK signalling pathways in piglet jejunum

Weaning may cause oxidative injury, immune response impairment, apoptosis and other injuries in piglets. Oxidative and endoplasmic reticulum stress (ERS) can elicit inflammatory responses, and persistent oxidative and ERS also may lead to apoptotic cascades, which is associated with the pathogenesis of multiple diseases. β-carotene, a natural carotenoid, has potential anti-inflammatory and antioxidant functions. However, the effect of β-carotene on apoptosis in weaned piglets and the detailed molecular mechanism remain unclear. In this study, we found that β-carotene decreased malondialdehyde (MDA) levels and increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in piglet serum. β-carotene could inhibit the mRNA levels of caspase-3 significantly, but had no significant inhibitory effect of the mRNA levels of caspase-9 and caspase-12 in the piglet jejunum. In addition, β-carotene decreased the activation of GRP78, CHOP, and JNK/p38 MAPK and the ratio of Bax/Bcl-2. Furthermore, β-carotene had a significant influence on the activation of ERS and apoptosis-related signals in TG-induced IPEC-J2. In the present study, β-carotene pre-treatment attenuated the ratio of Bax/Bcl-2 and prevented TG-induced increases in the level of PERK-CHOP and IRE1-JNK/p38 MAPK pathway activation in a dose-dependent manner. Overall, these findings indicate that β-carotene may protect weaning-induced apoptosis through inhibiting ERS.     

Factors affecting the virulence of Ralstonia solanacearum and its colonization on tobacco roots

Tobacco bacterial wilt caused by Ralstonia solanacearum is a serious disease affecting tobacco cultivation in southwest China. The response surface methodology was employed to evaluate the optimal conditions of tobacco bacterial wilt, and green fluorescent protein gene (gfp) labelling was applied to monitor the location and survival dynamics of R. solanacearum (Rs::gfp) on tobacco roots and in soil under these optimal conditions. The results showed that the highest wilt incidence was 91.13%, which occurred when the population reached 6.6 × 10⁶ CFU/g soil, the temperature was 30.55 °C, and the humidity was >81.42%. The Rs::gfp densely colonized the root tips and root hairs, and cells of Rs::gfp were observed intermittently in the elongation zone or at the point of the emerging lateral roots. The Rs::gfp number in the rhizosphere soil was 10.75‐, 73.13‐ and 74.86‐times higher than that in the bulk soil at 10, 15 and 20 days after transplantation, respectively. Increased colonization by Rs::gfp was related to the population of the pathogen, the environmental temperature and the humidity in the soil. These three conditions determined whether R. solanacearum would induce tobacco wilt. This is the first study to investigate factors affecting the virulence of a tobacco wilt bacterial pathogen, which is important for conducting field diagnosis and biocontrol of tobacco bacterial wilt.     

Effects of concentrate‐to‐forage ratios and 2‐methylbutyrate supplementation on ruminal fermentation,bacteria abundance and urinary excretion of purine derivatives in Chinese Simmental steers

This study evaluated the effects of dietary concentrate levels and 2‐methylbutyrate (2MB ) supplementation on performance, ruminal fermentation, bacteria abundance, microbial enzyme activity and urinary excretion of purine derivatives (PD ) in steers. Eight ruminally cannulated Simmental steers (12 months of age; 389 ± 3.7 kg of body weight) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement. Moderate‐concentrate (400 g/kg diet [MC ]) or high‐concentrate (600 g/kg diet [HC ]) diets were fed with or without 2MB (0 g/day [2MB ?] or 15.0 g/day [2MB +]). Dry matter intake and average daily gain increased, but feed conversion ratio decreased with the HC diet or 2MB supplementation. Ruminal pH decreased, but total volatile fatty acid increased with the HC diet or 2MB supplementation. Molar proportion of acetate and acetate‐to‐propionate ratio decreased with the HC diet, but increased with 2MB supplementation. Propionate molar proportion and ruminal NH ₃‐N content increased with the HC diet, but decreased with 2MB supplementation. Neutral detergent fibre degradability decreased with the HC diet, but increased with 2MB supplementation. Crude protein degradability increased with the HC diet or 2MB supplementation. Abundance of Ruminococcus albus , Ruminococcus flavefaciens , Fibrobacter succinogenes and Bufyrivibrio fibrisolvens as well as activities of carboxymethyl cellulase, cellobiase, xylanase and pectinase decreased with the HC diet, but increased with 2MB supplementation. However, abundance of Prevotella ruminicola and Ruminobacter amylophilus as well as activities of α‐amylase and protease increased with the HC diet or 2MB supplementation. Total PD excretion also increased with the HC diet or 2MB supplementation. The results suggested that growth performance, ruminal fermentation, CP degradability and total PD excretion increased with increasing dietary concentrate level from 40% to 60% or 2MB supplementation. The observed diet × 2MB interaction indicated that supplementation of 2MB was more efficacious for improving growth performance, ruminal fermentation and total PD excretion with promoted ruminal bacteria abundance and enzyme activity in the MC diet than in the HC diet.     

杨属( Populus)黑杨组(Aigeiros)种(品种)间核型比较

 对杨属黑杨组(Aigeiros) 的15个种(品种) 核型进行了分析, 结果如下: 箭杆杨( Populusnigra var. thevestina) , 2n = 38 = 3M + 29m + 5 sm + 1 st; 盖杨( P. del.cv. ×Lux ×P.×canadensis cv. Shanhaiguanensis) , 2n = 38 = 2M + 27m + 4 sm + 5 st (4SAT) ; 欧美杨107 (P1 ×euram ericana cv. ‘74 /76’) , 2n = 38 = 1M + 29m (1SAT ) + 5 sm + 3 st (3SAT) ; 欧美杨13 ( P. ×euramericana CL 13) , 2n = 38 = 3M + 23m + 6 sm + 3 st (1SAT ) + 3 t (3SAT) ; 加杨( P. ×canadensis Moench) , 2n = 38 = 1M + 27m + 6 sm + 4 st ( 4SAT) ; 辽杨×美洲黑杨(P.maximowiczii Henry ×P.deltoids Bartr. ) , 2n = 38 = 1M + 24m + 9 sm (2SAT ) + 4 st; 中尚8号( P. ×Zhongshangnensis) , 2n = 38 = 4M + 27m (1SAT ) + 2 sm + 3 st (2SAT ) + 2 t; 北京杨( P. ×beijingensis) , 2n = 38 = 3M + 28m + 3 sm + 4 st (2SAT) ; 鲁山杨( P. ×Liaoningensis) , 2n = 38 = 1M + 27m + 3 sm + 6 st (1SAT ) + 1 t (1SAT) ; 廊坊1号( P. CL ‘Langfang 1’) , 2n = 38 = 3M + 28m + 3 sm + 4 st (2SAT) ; 圣山杨(盖杨类) (P. ×gaixianesis) , 2n = 38 = 2M + 27m + 4 sm (1SAT ) + 4 st (3SAT ) + 1 t; 抗- 2 〔P. deltoids CL 2 (GMO) 〕, 2n = 38 = 26m + 7 sm (2SAT ) + 4 st (1SAT ) + 1 t (1SAT) ; 群改3号( P. ×Qungainensis 3) , 2n = 38 = 1M + 27m + 8 st (2SAT ) + 2 t (2SAT) ; 中金2号( P. ×Zhongjinnensis 2) , 2n = 38 = 1M + 18m + 13 sm (1SAT ) + 5 st (2SAT) + 1 t (1SAT) ; 辽宁杨( P. ×eur. cv. San Martino ×P. ×canadensis cv. Shanhaiguanensis) , 2n = 38 = 2M + 26m + 6 sm + 4 st。黑杨各种(品种) 核型均为2B型, 种(品种) 间核型差异主要表现在中部着丝点(M、m) 染色体数目(25～32) 和端部着丝点( st、t) 染色体数目变化(1～6) 上, 核型特征为种(品种) 鉴定提供了一定参考。     

巴旦杏在甘肃河西地区引种培育问题的探讨

该文通过分析巴旦杏在甘肃河西地区引种培育过程中出现的问题,总结出用容器育苗和大田开沟点播相结合来培育接穗,以山桃为砧木嫁接巴旦杏的引种驯化技术.结果表明,容器培育接穗比直接大田点播出苗率、成活率分别提高了10%和15%;巴旦杏与山桃嫁接表现出极好的亲和性,嫁接成活率为90%.     

不同轮作模式下小麦禾谷孢囊线虫的发生动态和种群密度

轮作是防治小麦禾谷孢囊线虫的重要农业措施,为了明确青海省春麦区不同轮作模式对小麦禾谷孢囊线虫的控制效果,采用田间大区试验法对生产中应用的6种轮作模式进行了研究。结果表明:不同轮作模式下,小麦禾谷孢囊线虫种群密度变化差异极显著,其中小麦与马铃薯、油菜、蚕豆轮作两年或以上能有效降低小麦禾谷孢囊线虫种群密度,土壤中的孢囊量减少39.31%~84.39%,单孢虫口数量减少73.21%~95.35%,虫口密度减少83.76%~97.82%;不同作物间,小麦与马铃薯或蚕豆的轮作效果(虫口密度减少74.39%~79.37%)显著优于小麦与油菜的轮作效果(虫口密度减少67.16%)。在同一地块相同条件下,种植油菜、蚕豆、马铃薯、小麦4种作物,小麦禾谷孢囊线虫均能正常孵化,4月底土壤中的2龄幼虫(J2)量增加,5月上旬达到高峰期,5月中旬开始,土壤中的J2、孢囊量、虫口密度和单孢虫口数量均急剧下降,6月至7月份下降幅度小,趋于稳定;田间空孢囊率于5月中旬至6月中旬急剧增加,7月份趋于稳定,8月份以前,4种作物田禾谷孢囊线虫的孵化动态和种群密度变化趋势一致,8月中旬,小麦田随着新孢囊脱落到土壤中,禾谷孢囊线虫种群密度开始上升,小麦收获后土壤中的孢囊量比播种前增加28.62%,虫口密度增加41.30%;而油菜、蚕豆、马铃薯田土壤中的孢囊量比播种前减少32.27%~48.36%,虫口密度减少70.91%~81.73%,8月中旬至10月份小麦田禾谷孢囊线虫种群密度极显著高于油菜、蚕豆、马铃薯田。     

应用聚合酶链式反应鉴定新疆棉花落叶型黄萎病菌

用一对棉花落叶型黄萎病菌的特异性引物D1和D2进行PCR扩增,对于落叶型黄萎病菌,该对引物可特异性地扩增产生一段550bp的产物,而非落叶型黄萎病菌则不能被扩增.供试的35个新疆黄萎菌系中,有3个菌系扩增出550bp大小的落叶型黄萎病菌特异性片段,表明目前新疆已存在落叶型黄萎病菌,用此技术可快速、准确地检疫和鉴定落叶型黄萎病菌.     

Effects of guanidinoacetic acid on growth performance,creatine metabolism and plasma amino acid profile in broilers

The objective of this study was to assess the effects of guanidinoacetic acid (GAA) on growth performance, creatine deposition and blood amino acid (AA) profile on broiler chickens. In Exp. 1, a total of 540 one‐day‐old Arbor Acres male broilers (average initial body weight, 45.23 ± 0.35 g) were divided randomly into five treatments with six replicates of 18 chicks each. Broilers were fed corn–soybean meal‐basal diets supplemented with 0, 600, 800, 1,000 or 1,200 mg/kg GAA for 42 days respectively. Results showed that dietary GAA inclusion increased average daily gain (ADG) and improved gain‐to‐feed ratio (G:F) from 1 to 42 days (p < 0.01). However, average daily feed intake was unaffected by dietary supplementation of GAA. As GAA inclusion increased, the contents of creatine in plasma and kidney were increased (linear, p < 0.01), while the contents of GAA and creatine in liver were decreased (linear, p < 0.01). Similarly, GAA supplementation was inversely related to concentrations of most essential AA in plasma. In Exp. 2, a total of 432 one‐day‐old Arbor Acres male broilers (average initial body weight, 39.78 ± 0.58 g) were divided randomly into four treatments with six replicates of 18 chicks each. Birds were fed a corn–soybean meal‐basal diet supplemented with 0, 200, 400 or 600 mg/kg GAA for 42 days respectively. Dietary inclusion of 600 mg/kg GAA significantly increased ADG and G:F of broilers (p < 0.05). In conclusion, dietary supplementation of 600–1,200 mg/kg GAA can effectively improve the growth performance in broiler chickens by affecting creatine metabolism and utilization efficiency of essential AA, and 600 mg/kg GAA is the minimum dose for improving performance.     

种衣剂中不同浓度杀虫剂成分对玉米苗期生长的安全性评价

选择克百威、丙硫克百威和丁硫克百威3种杀虫剂作为种衣剂有效杀虫成分,每种杀虫剂设置1%、2%、3%、…10%共10种浓度梯度,春天播种期进行玉米包衣播种,20 d后调查苗期植株的根长、根数、叶数和株高,验证3种杀虫剂不同浓度对玉米苗期的生长安全性。结果表明：在10%浓度以下,3种杀虫剂进行种子包衣处理,玉米苗期生长均未产生药害,植株生长正常。     

禾谷镰孢菌产玉米赤霉烯酮毒素zearalenone的PCR检测

玉米赤霉烯酮（zearalenone,ZEN）是由镰孢菌产生的真菌毒素,该毒素具有雌性激素生物活性。PKS4基因是禾谷镰孢菌中玉米赤霉烯酮生物合成途径中的必需基因。根据PKS4基因序列,设计一对PKS4基因特异性引物,通过检测PKS4基因的存在间接检测ZEN毒素的产生。特异引物在禾谷镰孢菌菌株以及被禾谷镰孢菌侵染的小麦籽粒中都能稳定地扩增出大小为1 076 bp的特异片段,扩增片段与PKS4基因（DQ019316）相同区段序列相似性达99.63%。同时,酶联免疫吸附法（ELISA）验证了PCR的检测结果,证明了该技术的可靠性。