Eocene El Niño: evidence for robust tropical dynamics in the "hothouse"

Much uncertainty surrounds the interactions between the El Ni?o-Southern Oscillation (ENSO) and long-term global change. Past periods of extreme global warmth, exemplified by the Eocene (55 to 35 million years ago), provide a good testing ground for theories for this interaction. Here, we compare Eocene coupled climate model simulations with annually resolved variability records preserved in lake sediments. The simulations show Pacific deep-ocean and high-latitude surface warming of approximately 10 degrees C but little change in the tropical thermocline structure, atmosphere-ocean dynamics, and ENSO, in agreement with proxies. This result contrasts with theories linking past and future "hothouse" climates with a shift toward a permanent El Ni?o-like state.     

18O(π+,π-)18Ne双电荷交换反应分析

应用Glauber理论，对(18)O（π~＋，π~-）、(18)Ne双电荷交换反应进行分析，假定(18)O和(18)Ne由2价核子和4α核心组成，计算了共振区Tx＝164MeV的微分截面。结果表明，理论与实验符合得较好。     

Dinosaur body temperatures determined from isotopic (¹³C-¹⁸O) ordering in fossil biominerals

The nature of the physiology and thermal regulation of the nonavian dinosaurs is the subject of debate. Previously, arguments have been made for both endothermic and ectothermic metabolisms on the basis of differing methodologies. We used clumped isotope thermometry to determine body temperatures from the fossilized teeth of large Jurassic sauropods. Our data indicate body temperatures of 36° to 38°C, which are similar to those of most modern mammals. This temperature range is 4° to 7°C lower than predicted by a model that showed scaling of dinosaur body temperature with mass, which could indicate that sauropods had mechanisms to prevent excessively high body temperatures being reached because of their gigantic size.     

苏云金芽孢杆菌新分离株S_(18-4) δ-内毒素基因在Btk·BE_(20)中的克隆和表达

选用土壤新分离株Ｓ１８－４为供体菌,以ＰＨＴ３１０１穿梭质粒为载体,载体和供体ＤＮＡ用Ｐｓｔｌ酶切后进行连接,用电激法将重组质粒转入苏云金芽孢杆菌无晶体突变株Ｂｔｋ·ＢＥ２０中。经ＳＤＳ－ＰＡＧＥ蛋白电泳及扫描电镜观察,证明δ－内毒素基因得到了表达,并具有很高的表达量。生物测定结果显示,重组株对夜蛾科幼虫具有比野生株Ｓ１８－４更强的杀虫毒性。     

Foliar δ~(13)C Values and Water Use Efficiency of Semi-arid Plants in Horqin Sandy Land,China

Water was a key factor restricting the plantation in sandy areas. Foliar δ~(13)C value regarded as an indicator of longterm water use efficiency(WUE) of plants was generally used to evaluate the adaptability of plants to arid and semi-arid environment. In Horqin sandy land of China, the foliar δ~(13)C values of 114 species in 35 families naturally growing in the area, and 15 species of sand-fixing trees and shrubs were measured and analyzed in 2012. The results showed that 97 species in all 114 species were C_3 plants and only 17 species were C_4 plants. Most C_4 plants belonged to Gramineae family. The foliar δ~(13)C value of C_3 plants was between -25.000 and -31.075‰ with an average of-28.226‰, while those of C_4 plants between -12.578 and -16.334‰, with an average of -13.678‰. The δ~(13)C values of mature leaves collected in August were averagely 0.85‰ less than that of juvenile leaves collected in June. The foliar δ~(13)C values and WUE of 15 sand-fixing tree species in Horqin sandy land ranked in the order as: S.vulgaris H.rhamnoides C.ovata P.mongolica T.chinensis R.typhina S.matsudana E.angustifolia U.pumila S.gordejevii X.sorbifolia C.microphylla H.fruticosum C.korshinskii E.bungeanus.     

Participatory Guarantee Systems (PGS) in Mexico: a theoretic ideal or everyday practice?

Third-party certification (TPC), the most common organic certification system, has faced growing criticism in recent years. This has led to the development of alternative certification systems, most of which can be classed as Participatory Guarantee Systems (PGS). PGS have been promoted as a more suitable, cheaper and less bureaucratic alternative to TPC for local markets and are associated with additional benefits such as empowering smallholder farmers, facilitating farmer-to-farmer learning and enhancing food security and sovereignty. PGS have spread rapidly in the past few years, but studies suggest that they are facing numerous challenges that, if not addressed, may jeopardise these benefits. Using the example of three Mexican PGS initiatives, this paper explores the main challenges faced by PGS, specifically those predominantly found in producer-run PGS initiatives. Based on producer and consumer surveys, semi-structured and informal interviews, and participant and non-participant observation, the key challenges that emerged were continuous implementation of the certification process, time constraints, personal conflicts and conflict avoidance. The paper further argues that the requirements for PGS recognition under the Mexican Law for Organic Products may also threaten the continued existence of PGS and suggests that mechanisms for managing conflicts, incentivising PGS participation and mitigating opportunity costs are key if PGS are to continue to develop.     

大肠杆菌O157:H7 CWN11Ⅲ效应因子tccP和tccP2基因序列分析(英文)

[目的]分析大肠杆菌O157:H7CWN11效应因子tccP和tccP2基因序列。[方法]PCR扩增tccP和tccP2完整基因,以及含有tccP和tccP2侧翼序列的基因,测序分析。[结果]CWN11同时含有tccP和tccP2两个基因,前者含有一个富含脯氨酸的重复序列,而tccP2含有5.5个脯氨酸重复序列,并且第28位密码子无缺失,非假基因。参考菌株SakaitccP含有4.5个脯氨酸重复序列,而tccP2为假基因。[结论]首次报道非典型大肠杆菌O157:H7CWN11同时含有完整的tccP和tccP2,并且tccP可能编码无功能蛋白,而tccP2在细菌定植和激发信号级联中发挥替代功能。     

Genetic diversity center of cultivated soybean(Glycine max) in China——New insight and evidence for the diversity center of Chinese cultivated soybean

Information on the center of genetic diversity of soybean(Glycine max) will be helpful not only for designing efficient strategies for breeding programs, but also for understanding the domestication and origin of this species. Here, we describe an analysis of genetic diversity based on simple-sequence repeat(SSR) variations within a core collection of 2 111 accessions of Chinese soybean landraces. Prior to the diversity assessment, the geographic origin of each accession was mapped. The map was then divided into grids each 2.5° in latitude and 5° in longitude. We found two regions that had higher number of alleles(NA) and greater polymorphic information content(PIC) values than the others. These regions are adjacently located within grid position of 30°–35°N×105°–110°E, which includes the valley of the middle and lower reaches of the Wei River, and the valley of the upper reaches of the Hanjiang River. It was also observed that in many regions, genetic diversity decreased with the increase in distance from the center. Another region, in northern Hebei Province(115°–120°E×40°–42.5°N), was observed having higher diversity than any surrounding regions, indicating that this is a sub-center of soybean diversity. Based on the presented results, the domestication and origin of soybean are also discussed.     

The breeding of japonica rice in northern China: An 11-year study(2006–2016)

The world's population is facing food shortages due to climate change and the competition for arable land between food and energy crops. Many national and international projects to develop super rice cultivars were established in recent decades to attain a ‘third leap forward' in rice production. In order to evaluate the breeding process in northern China, an 11-year tracking survey of japonica rice breeding, which involved a total of 520 rice accessions and 67 test plots, was completed in this study. The results showed that the yields of these accessions had increased stably, which was similar to control check varieties(CKs). The breeding strategy reduced the panicle number and increased the grain number per panicle through an increase of spikelet density(number of grains per centimeter on the panicle). This high spikelet density benefits not only the yield but also the blast resistance and amylose content. At higher latitudes, the preferred rice accessions had slim grain shape and extended growth period. In the middle latitudes among the test plots, the breeders focused on reducing the amylose content to improve the cooking quality of the rice accessions. Yield and blast resistance were the two highest priorities during the breeding selection process. The present study evaluated the breeding process in northern China during the last decade, which may lead to new insights into the future of rice breeding.     

Gene Cloning and Tissue-Specific Expression of G Protein β Subunit in Microplitis mediator (Hymenoptera: Braconidae)

A gene encoding a novel G protein β subunit of β1 subclass, GβMmed was isolated from Microplitis mediator (Hymenoptera: Braconidae). The full-length sequence of GβMmed is 1 119 bp, the cDNA contains a 1 023 bp open reading frame that encodes a protein with 340 amino acids, and the predicted molecular weight of GβMmed is 37.23 kDa and isoelectric point is 5.86. By the quantitative real-time RT-PCR method, the tissue-specific expression and quantitative changes in the developmental expression profile of GβMmed were detected. It was found that GβMmed was abundantly expressed in M. mediator antennae, head (without antennae), thorax, abdomen, legs and the wings, and especially at high levels in abdomen. In antennae, expression varied through 1st day before emergence to 5-d-old adults, and had equal expression levels detected in females and males in total. In head, GβMmed expresses while initially high in females, and have another peaked in stage 4 and 1st day, in males showed a peak of GβMmed expression prior to emergence and relatively low levels after emergence. In female abdomen GβMmed expression levels have two peaks in stage 1 and the 5th d, but just have one peak in male abdomen in stage 1. In all other tissues expression was low and stable.     

降水-滴水的δ~(18)O/δD年季变化及与大气环流的关系——以重庆芙蓉洞地区为例

通过对2011年4月至2012年12月期间重庆市芙蓉洞外大气降水氢氧稳定同位素、降水量、温度和洞穴滴水、池水中δD,δ18 O的连续监测,分析了芙蓉洞地区降水中δD,δ18 O的变化特征及其与ENSO事件和季风指数的关系.当地大气降水线方程的截距和斜率均大于全球大气降水线,大气降水中δD和δ18 O值与大气温度成负相关关系,δ18 O与温度的相关系数为r=-0.693(n=20);与降水量的相关系数为r=-0.121(n=20);过量氘(d)也体现出夏季低冬季高的特点.不同季节的水汽源地差异是导致该地区大气降水中δD和δ18 O值出现季节差异的主要原因.芙蓉洞所在的中国南方季风区大气降水中氢氧稳定同位素组成与ENSO有密切联系.当厄尔尼诺发生时,西太平洋副热带高压势力强盛,西北太平洋季风指数高,导致中国南方地区大气降水中氢氧稳定同位素值偏重;拉尼娜发生时,东南信风强,印度洋季风指数高,降水稳定同位素偏轻.     

Deciphering the morpho–physiological traits for high yield potential in nitrogen efficient varieties(NEVs):A japonica rice case study

The use of nitrogen(N)-efficient rice(Oryza sativa L.) varieties could reduce excessive N input without sacrificing yields. However, the plant traits associated with N-efficient rice varieties have not been fully defined or comprehensively explored. Here, three japonica N-efficient varieties(NEVs) and three japonica N-inefficient varieties(NIVs) of rice were grown in a paddy field under N omission(0 N, 0 kg N ha-1) and normal N(NN, 180 or 200 kg N ha-1) treatments. Results showed that NEVs exhib...     

Genetic Differentiation Analyses Based on mtDNA COⅡ Gene Sequences Among Different Geographic Populations of Aphis glycines(Hemiptera: Aphididae) in Northeast China

Aphis glycines(Hemiptera: Aphididae) is considered as a cosmopolitan pest of cultivated soybean, major diffi culties in its control measures may be due to its higher genetic diversity; however, the knowledge about population genetic diversity of this species is limited. This study aimed to represent the genetic differentiation among different geographic populations of soybean aphid in Northeast China. In order to investigate and assess the genetic diversity, genetic differentiation, molecular variance, population structure, ecological importance and evolutionary history of A. glycines, we sequenced a fragment of one protein-coding gene, the cytochrome c oxidaseⅡof mitochondrial DNA gene. The results showed that four haplotypes were defi ned among COⅡ gene of 180 sequences of soybean aphid in Northeast China including H1 shared by all the populations. Lower haplotype diversity(Hd=0.3590±0.0420) and nucleotide diversity(Pi=0.0012±0.0002) were observed and high gene flow was detected in every two populations, while most of the variation(80.81%) arose from variability within A. glycines from individuals. Low genetic differentiation and high gene fl ow(Nm=2.106) indicated a high migration rate between the populations, which might reveal that gene flow in different geographic populations did not affect by geographical distance. The phylogenetic tree and the haplotype network of A. glycines were obtained based on sequences of COⅡ gene, there were no signifi cant genealogical branches or clusters recognized in NJ tree, and no clear distribution, delineation of haplotypes were demonstrated in the haplotype network according to geographical location. This study rejected the vicariance hypothesis: geographic isolation could be a barrier and it restricted A. glycines gene fl ow among 10 populations.     

Halloween genes AhCYP307A2 and AhCYP314A1 modulate last instar larva–pupa–adult transition,ovarian development and oogenesis in Agasicles hygrophila(Coleoptera: Chrysomelidae)

Ininsects,ecdysteroidsaresynthesizedbygenesoftheHalloweenfamilyandplayimportantrolesinseveralkey developmentalevents,includingmoltingandmetamorphosis.However,therolesofthesegenesinAgasicles hygrophila are still largely unknown.In this study, the expression patterns of the two Halloween genesAhCYP307A2andAhCYP314A1weredeterminedbyquantitativePCR(qPCR)atdifferentdevelopmentalstages.Moreover,the functions of these two genes were explored using RNA interference (RNAi), and ovarian development was ob...