中国施用生物炭对番茄产量和品质效应的Meta分析

为定量分析生物炭施用对番茄产量和品质的时空效应和影响机制,同时为番茄生产中生物炭合理施用量的确定提供依据。该研究通过检索文献整合已发表的相关田间试验数据,采用Meta-analysis法分析了生物炭施用条件下,生物炭特性、土壤条件、田间管理措施与时空特性对番茄产量和品质的综合效应,并对各影响因素进行通径分析。结果表明：施用生物炭显著增加了番茄产量、果实Vc、可溶性糖和可溶性固形物含量（P<0.05）,增长率分别为 30.7%（95%置信区间（confidence interval,CI） 为27.6%～33.9%）、13.8%（95% CI为10.8%～16.9%）、6.7%（95% CI为3.3%～10.2%）和10.7%（95% CI为5.8%～15.8%）,而番茄果实硝酸盐含量降低了3.1%（95% CI为-6.7%～0.8%）,对番茄果实糖酸比含量增加效应不显著（95% CI为-3.0%～7.9%）;番茄产量效应的亚组分析表明,生物炭施用在不同时间和区域特征下对番茄增产效应影响显著（P＜0.01）,随着时间的推移,生物炭施用对番茄增产效应呈波动式增长趋势,华北、东北农田区的番茄增产效应不显著;土壤有机质含量与番茄增产率呈正相关关系,土壤pH值与番茄增产率呈负相关关系,番茄增产率随土壤全氮及硝酸钾含量的增加呈先增后减趋势;田间管理措施对番茄产量效应分析结果表明,生物炭施加量>40～80 t/hm²时,增产率可达37.8%（95% CI为33.5%～42.1%）,生物炭热解温度在400～600 ℃内,生物炭pH值控制在>8～9为最优;生物炭施用量、生物炭pH值和产量年份是影响生物炭增产效果的3个主要因素。研究结果可为番茄生产中科学、合理生物炭施用量的确定提供理论支撑。     

饲用酶制剂在反刍动物营养中的应用进展

一般情况下,在瘤胃中粗饲料细胞壁组分的消化利用率较低,由于其复杂紧密的结构限制了动物对粗饲料的利用。因此,在反刍动物生产中提高粗饲料利用率的应用研究是非常必要的,不仅改善饲料利用率、提高动物生产性能,还为饲料资源的开发与利用乃至为畜牧业发展提供有效途径。而饲用酶制剂以其绿色、环保、安全等特点成为了该研究领域的热点。通常采用体外和半体内法评定酶制剂处理对粗饲料体外发酵和瘤胃降解特性的影响,并采用体内法评价酶制剂在反刍动物营养中的应用效果。研究表明,外源酶制剂的应用能够有效提高饲料消化率、奶牛产量、肉牛增重和肉羊增重,但其效果不一致,其效果受很多因素的影响,包括酶种类、酶活性、饲粮组成、添加水平、添加方式、动物种类及生长性能等。另外,由于人们对所用酶产品的生化特性掌握不足,导致了对其作用机理、优化条件及影响其作用效果因子的了解不够充分。如酶活性作为酶制剂最主要的生化特性,在使用前往往被忽略检测,并且目前国内外对酶活性的检测及质量评定还没有统一的标准。然而研究结果间直接进行比较也是不科学不合理的。本研究主要从饲用酶制剂的发展历程,反刍动物营养中纤维降解酶的作用机理、应用效果和影响其作用效果的因素以及存在问题等方面进行了综述,旨在为饲用酶制剂在反刍动物营养中的应用提供系统的科学知识。     

成纤维细胞生长因子（FGF）研究进展

介绍了成纤维细胞生长因子（FGF）的种类和作用机理。同时,对国内外对FGF在胚胎发育、器官形成及毛囊发育过程中的作用等方面的研究进展进行了综述。     

Comparison of acetate tape impression with squeezing versus skin scraping for the diagnosis of canine demodicosis

This study compared the sensitivity of acetate tape impression and skin squeezing with that of deep skin scraping for the diagnosis of demodicosis in dogs. Demodex canis was detected in 100% of acetate tape impressions obtained after skin squeezing and in 90% of deep skin scrapings. There was a significant difference (P < 0.001) between the techniques in the total number of mites detected. Acetate tape impression with skin squeezing was found to be more sensitive than deep skin scraping and is an alternative diagnostic method for canine demodicosis.     

Comparison of the pharmacokinetics and thermal antinociceptive pharmacodynamics of 20 µg kg−1 buprenorphine administered sublingually or intravenously in cats

Little is known about the analgesic action of buprenorphine (BUP) in cats. Relative to man, the cat has a more alkaline oral pH, which may make this an effective route for administering BUP in this species. This study aimed to assess and compare the pharmacokinetics and pharmacodynamics of sublingual (S‐L) and IV administration of BUP. Thermal threshold (TT) was measured and blood samples were collected following IV or S‐L administration (20 µg kg^?1) of the injectable formulation. Six cats (five spayed females, one castrated male, 4.1–6.6 kg) were used. Each cat received both treatments in a randomized cross‐over study design with 1 month between experiments. Twenty‐four hours prior to each study, the lateral thorax of each of the cats was shaved, cephalic and jugular catheters placed, and oral pH measured. On the day of the study, TT was measured using a ‘thorax‐mounted’ thermal threshold‐testing device specifically developed for cats. The cats were free to move around. Skin temperature was recorded before each test, then the heater activated. When the cat responded by flinching, turning, or jumping, the stimulus was terminated and the threshold temperature was recorded. The thermal threshold cut‐off point was 55.5 °C. Three baseline thresholds were recorded before treatment with S‐L or IV (via cephalic catheter) BUP (20 µg kg^?1). Blood was withdrawn (jugular) at 1, 2, 4, 6, 10, 15, 30, 45, 60 minutes and at 2, 4, 6, 8, 12, and 24 hours post‐administration. TT was measured every 30 minutes?6 hours, 1–12 hours, and at 24 hours post‐administration. Plasma was immediately separated, stored at ?20.5 °C, and assayed within 4 months using a commercially available ¹²⁵I radioimmunoassay. Threshold data were analyzed using anova with a repeat factor of time. No adverse effects were noted. Pupils were dilated for up to 9 hours post‐BUP. Behavioral changes were calm euphoria. Measured oral pH was 9 in each cat. Pre‐treatment mean threshold (±SD) was 41.2 ± 0.9 °C in the S‐L group and 40.8 ± 0.85 °C in the IV group. There were no significant differences between the groups with respect to thresholds over time (p = 0.72). Thresholds were significantly increased from 30 to 360 minutes in both the groups (>44.615 °C). Peak plasma BUP (C_max) was lower (11 ± 6.7 ng mL^?1vs. 92.9 ± 107.9 ng mL^?1) and occurred later (T_max) (30 minutes vs. 1 minute) after S‐L compared to IV administration, respectively. BUP (20 µg kg^?1)‐administered S‐L or IV provided antinociception between 30 and 360 minutes after administration. Plasma levels did not correspond to TT.     

2株广西鹅源基因XII型新城疫病毒的病原学分析

【目的】深入了解2株广西鹅源基因XII型新城疫病毒(NDV)的病原学特征,为NDV流行分布的系统监测和新城疫(ND)的科学防控提供参考依据。【方法】对2株广西鹅源基因XII型NDV(Goose/China/GX02/2018和Goose/China/GX17/2018)进行病毒噬斑纯化,通过致死鸡胚平均死亡时间(MDT)和脑内接种致病指数(ICPI)试验确定其致病性,分析F蛋白和HN蛋白氨基酸序列与参考毒株的差异位点,并基于F基因全长进行遗传进化分析。【结果】经过DF-1细胞4个代次噬斑纯化可获得2株分离株的纯化株,对应的MDT分别为54和48 h,ICPI均为1.65。2株分离株的基因组长度均为15192 nt,其3’端引导序列为55 nt,5’端尾随序列为114 nt;基于F基因核苷酸序列相似性构建的基因XII型NDV系统发育进化树显示,2株分离株(Goose/China/GX02/2018和Goose/China/GX17/2018)均属于基因XIIb亚型,与我国广东分离株属于同一基因亚型,且我国2010年的分离株、2011年的分离株及2017年后的分离株分别形成3个小分支。2株...     

Effect of Alkali Stress on Soluble Sugar, Antioxidant Enzymes and Yield of Oat

Alkali stress can cause severe crop damage and reduce production. However, physiological processes involved in alkali stress in oat seedlings are not well understood. In this study, physiological responses and yield of oat to alkali stress were studied using the alkali-tolerant oat genotype Vao-9 and the alkali-sensitive oat genotype Baiyan 5. The results were: (i) low concentrations of alkali stress (25 and 50 mmol L-1) significantly reduced the yield and grain weight while increased the oat grain number per spike. A negative correlation between yield and malondialdehyde (MDA) content at the jointing and grain filling stages and positive correlations between yield on one hand and superoxide dismutase (SOD), and peroxidase (POD) activities on the other at the jointing stage were observed. There was a positive correlation between MDA and soluble sugar at the grain filling stage; (ii) soluble sugar content was increased at the jointing and grain filling stages and decreased at the heading stage by alkali stress; (iii) alkali stress increased the SOD activity during the heading and grain filling stages, and increased the POD activity at the heading stage. As compared to the control, the increase of MDA contents in alkali-treated oat was observed, during the jointing, heading and grain filling stages; (iv) under alkali stress, the oat genotype Vao-9 showed higher antioxidant enzyme activity and lower soluble sugar contents during the heading stage, and lower MDA contents than those in the oat genotype Baiyan 5 under alkali stress. The result suggested that the high ROS scavenging capacity and soluble sugar levels might play roles in oat response to alkali stress.     

pGRF基因质粒对猪生长性能及血液指标的影响

研究猪生长激素释放因子(pGRF)基因质粒对猪生长性能和血液指标的影响,选用24头大白×长白二元杂交去势公猪(平均体质量17.25±0.62 kg),随机分为4个处理,每处理6个重复,分别经臀部注射0、4、6和8 mg的pGRF基因质粒.结果表明:pGRF基因质粒对猪不同生长阶段的影响不同,注射pGRF基因质粒后1～8周效果好于9～15周且促生长效果与剂量有关.整个试验期以6 mg效果最佳,日增体质量(ADG)和耗料增重比(F/G)较对照组分别提高8.02%(P<0.05)和降低7.64%(P<0.05).注射4和6 mg pGRF基因质粒能显著提高猪血液中生长激素的浓度(P<0.05).在注射pGRF基因质粒105 d后,血液中血糖、血清尿素氮和甘油三酯与对照组无显著差异.     

高压水蒸气蒸馏法提取和厚朴树枝有效精油成分

为了有效利用和厚朴的树枝,在1.5、1.7、2.1 MPa等不同压力条件下,对和厚朴树枝进行高压水蒸气蒸馏以提取有效成分厚朴酚与和厚朴酚。对蒸馏液和废液进行气相色谱-质谱(GCMS)分析,并以有机溶剂提取出的厚朴酚与和厚朴酚作为全部提取量,计算厚朴酚与和厚朴酚的转移率。结果表明,1.5 MPa高压水蒸气蒸馏的精油收率为4.53%,厚朴酚与和厚朴酚的转移率分别为33.61%和30.59%。2.1 MPa高压水蒸气蒸馏的精油收率最高(9.05%),但是厚朴酚与和厚朴酚的转移率比1.5 MPa条件下的转移率降低。在高温高压条件下,短时间内从和厚朴树枝中得到了高提取率的厚朴酚与和厚朴酚。和厚朴的蒸馏压力越高,各成分的提取率越高,但随着压力的增加,提取成分有可能发生化学变化。     

Hydrogen radicals, nitrogen radicals, and the production of O3 in the upper troposphere

The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O3 than expected.