绵羊卵泡发育过程中关键信号通路研究进展

卵泡从原始卵泡发育为成熟卵泡，直至排卵、黄体发育等过程都受到精密的调控，产生大量的优势卵泡是绵羊产多羔及实现快速扩繁的关键因素。研究发现，相关信号通路和转录因子通过影响绵羊卵泡中卵母细胞、颗粒细胞的生长，进而调控卵泡的发育成熟，对这些信号通路进行深入了解，有助于探索卵泡发育的调控机制，早日实现绵羊高效繁育。Notch是卵泡发育过程中发挥重要作用的高度保守信号通路，PI3K/AKT/mTOR信号通路各成员都是广泛存在于细胞内的信号转导分子，在卵泡发育早期发挥了主要作用，还有间隙连接（gap junction，GJ）和跨带突触（transzonal projections，TZPs）等物理连接方式，在细胞间的交流通讯起到重要作用。作者详细介绍了Notch信号通路、PI3K/AKT/mTOR信号通路、间隙连接及跨带突触的结构功能在绵羊卵泡发育中的调控作用，为进一步探明绵羊卵泡发育的调控机制提供参考。     

Interspecific cross‐hybrids of Nicotiana tabacum L. cv. (gla.) S ‘K326’ with Nicotiana alata

In order to introduce the Tomato Spotted Wilt Virus (TSWV) resistance from Nicotiana alata into Nicotiana tabacum, a cytoplasmic male sterility (CMS) line of N. tabacum (N. tabacum L. cv. (gla.) S ‘K326’), was successfully crossed with N. alata. Despite a high DNA content variability, F₁ hybrids could be classified in two subgroups, a major one encompassing fertile hybrids morphologically similar to their tobacco maternal parent but TSWV sensitive, and a minor one displaying sterile hybrids showing an intermediate phenotype and TSWV resistant. In order to elucidate the unexpected fertility recovery of the fertile F₁ plants, some N. alata fertility restoration ppr genes were cloned and were shown to be differentially expressed between parental lineages as well as between both F₁ subgroups, suggesting that N. alata contains fertility restoring allele able to overcome the CMS of N. tabacum.     

高效液相色谱法测定天女木兰叶中游离酚和结合酚

[目的]进一步了解天女木兰中酚类物质种类及含量。[方法]利用高效液相色谱仪对天女木兰叶片中游离酚、结合酚和酯化酚进行定性定量测定。[结果]在10种检测酚中,天女木兰叶片中含有香豆酸和绿原酸2种游离酚,含有咖啡酸、香豆酸、香豆素和表儿茶素4种结合酚及香豆素和香豆酸2种酯化酚;各种形式的香豆酸广泛存在于叶片中。[结论]该研究建立的高效液相色谱法测定天女木兰叶中游离酚和结合酚的方法准确、可靠。     

Influence of Soil Particle Size on the Measurement of Sodium by Near-Infrared Reflectance Spectroscopy

This study evaluates the effect of soil particle size (SPS) on the measurement of exchangeable sodium (Na) (EXC-Na) by near-infrared reflectance (NIR) spectroscopy. Three hundred thirty-two (n = 332) top soil samples (0–10 cm) were taken from different locations across Uruguay, analyzed by EXC-Na using emission spectrometry, and scanned in reflectance using a NIR spectrophotometer (1100–2500 nm). Partial least squares (PLS) and principal component regression (PCR) models between reference chemical data and NIR data were developed using cross validation (leaving one out). The coefficient of determination in calibration (R²) and the root mean square of the standard error of cross validation (RMSECV) for EXC-Na concentration were 0.44 (RMSECV: 0.12 mg kg^–1) for soil with small particle size (SPS-0.053) and 0.77 (RMSECV: 0.09 mg kg^–1) for soils with particle sizes greater than 0.212 mm (SPS-0.212), using the NIR region after second derivative as mathematical transformation. The R² and RMSECV for EXC-Na concentration using PCR were 0.54 (RMSECV: 0.07 mg kg^–1) and 0.80 (RMSECV: 0.03 mg kg^–1) for SPS-0.053 and SPS-0.212 samples, respectively.     

L'electrode potassium pour l'analyse des tissus vegetaux (The potassium electrode for plant tissue testing)

Abstract

A potassium specific‐ion electrode equiped with a “sensing module” was compared with atomic absorption for potassium determination in plant tissue. The potentiometric readings were stable and reproducible, and were of the same order of magnitude as those obtained by atomic absorption. The correletion coefficient obtained between the two analytical methods were highly significant; but it was higher for corn leaves, sugarbeet leaf‐blades and petioles respectively.     

Shelf-Life of Spanish Mackerel (Scomberomorus commerson) from Northern Australian Waters

Abstract

The shelf-life of Spanish mackerel caught by line fishing in Northern Australian waters was evaluated. Spiked fish were stored in ice either headed and gutted or left uncut and subjected to sensory, nucleotide, pH, histamine and microbial analysts and the rigor pattern recorded. There was little difference between the two product forms. Rigor in uncut fish lasted for 14 ± 9.8 hours and in headed and gutted fish for 19.6 ± 16.3 hours. Spanish mackerel retained good sensory quality for up to 14 days. The bacterial load reached 105 cfu/g by 18 days. K values were low for most of the storage time, < 40%. Histamine levels did not develop more than 10 mg/kg during storage. The pH of Spanish mackerel did not change much even though bacterial levels become high.     

紫云英与双季稻秸秆协同利用影响稻田土壤钾循环与平衡

稻草还田和冬种绿肥是维持稻田地力和化肥替代的重要方式之一.本研究以在湖南酸性红黄泥和碱性紫潮泥两种典型稻田土壤上进行了2年的紫云英-双季稻定位试验为对象,分析紫云英和双季稻秸秆协同利用对稻田土壤K循环的影响.两土壤试验处理一致,包括稻田冬闲(FRR)、冬种紫云英(MvRR)及冬种紫云英与水稻秸秆协同利用(MvRR+St)3个处理.结果表明:与冬闲和冬种紫云英相比,紫云英与水稻秸秆协同利用未影响红黄泥土壤各形态钾的含量,但显著提高紫潮泥土壤速效钾和非交换性钾的含量,其中紫潮泥土壤水溶性钾、非特殊吸附钾及特殊吸附钾的含量较冬种紫云英处理分别提高了134.0％、93.0％、73.4％;两种典型稻田土壤上紫云英与水稻秸秆协同利用显著提高下茬作物紫云英的全K含量及吸K量,且紫云英的吸K量为紫潮泥>红黄泥;两种典型稻田土壤上冬种紫云英与水稻秸秆协同利用均未影响早、晚稻产量及籽粒K积累;在稻田各种植季和周年目前的K投入水平下,两种典型稻田土壤上冬种紫云英与水稻秸秆协同利用处理均存在K盈余(红黄泥K盈余量为401.15 kg·hm-2、紫潮泥K盈余量为403.42 kg·hm-2),说明冬种紫云英与水稻秸秆协同利用能减少双季稻生产中的化学钾肥投入量.综上所述,紫云英和双季稻秸秆协同利用有益于稻田土壤的K循环与平衡.     

MAP3K5基因在畜禽剩余采食量表型调控中的研究进展

随着分子遗传学的发展,已经鉴定出了影响剩余采食量(RFI)的大量数量性状位点和候选基因。有丝分裂原活化蛋白3激酶5(MAP3K5),也称凋亡信号调节激酶1(ASK1),属于MAPK超家族基因之一。目前,已有细胞外信号调节蛋白激酶(ERK)、c-Jun N-末端激酶(JNK)和p38丝裂原激活蛋白激酶(p38-MAPK)这3个MAPK家族成员在哺乳动物细胞中被克隆和鉴定,其主要作用机制是介导3条MAPKs信号通路,从而影响家畜的生长、体型及产奶性状等。课题组在前期对RFI的研究中筛选出与牛剩余采食量相关的MAP3K5基因,但其功能作用尚不明确,笔者在此基础上回顾了该基因的结构、生物学功能,概述了该基因在主要畜禽采食量变异及人类肥胖表型中的功能及作用,并从遗传学的角度重点分析了MAP3K5基因在畜禽RFI表型调控中的可能机制。通过对MAP3K5基因在畜禽RFI表型调控中的研究进展进行综述,期望为后期深入开展MAP3K5基因在畜禽采食量性状调控中的分子机制研究提供思路;对于其他可能通过MAP3K5基因影响畜禽表型的因素(如肠道菌群)有待进一步探讨。     

噬菌体Bp7尾丝蛋白gp37的原核表达与鉴定

为了研究噬菌体尾丝蛋白gp37在识别宿主菌大肠埃希菌K12过程中的作用,PCR扩增获得gp37基因C端1 161bp序列,以EGFP为荧光标签,构建重组表达质粒pET-28a-EGFP-gp37,在大肠埃希菌BL21(DE3)中IPTG诱导表达重组蛋白EGFP-gp37,亲和层析纯化蛋白。SDS-PAGE及Western blot检测结果表明,重组蛋白EGFP-gp37在大肠埃希菌BL21(DE3)为可溶性表达,表达量占菌体总蛋白量的23%。EGFP-gp37融合蛋白与大肠埃希菌K12相互作用,激光共聚焦显微镜检测结果显示,尾丝蛋白gp37能够吸附到宿主菌K12表面,表明尾丝蛋白gp37参与宿主菌受体的识别和吸附过程。