Molecular relationships between Australian annual wild rice,Oryza meridionalis,and two related perennial forms

Background

The perennial, Oryza rufipogon distributed from Asia to Australia and the annual O. meridionalis indigenous to Australia are AA genome species in the Oryza. However, recent research has demonstrated that the Australian AA genome perennial populations have maternal genomes more closely related to those of O. meridionalis than to those found in Asian populations of O. rufipogon suggesting that the Australian perennials may represent a new distinct gene pool for rice.

Results

Analysis of an Oryza core collection covering AA genome species from Asia to Oceania revealed that some Oceania perennials had organellar genomes closely related to that of O meridionalis (meridionalis-type). O. rufipogon accessions from New Guinea carried either the meridionalis-type or rufirpogon-type (like O. rufipogon) organellar genomes. Australian perennials carried only the meridionalis-type organellar genomes when accompanied by the rufipogon-type nuclear genome. New accessions were collected to better characterize the Australian perennials, and their life histories (annual or perennial) were confirmed by field observations. All of the material collected carried only meridionalis-type organellar genomes. However, there were two distinct perennial groups. One of them carried an rufipogon-type nuclear genome similar to the Australian O. rufipogon in the core collection and the other carried an meridionalis-type nuclear genome not represented in the existing collection. Morphologically the rufipogon-type shared similarity with Asian O. rufipogon. The meridionalis-type showed some similarities to O. meridionalis such as the short anthers usually characteristic of annual populations. However, the meridionalis-type perennial was readily distinguished from O. meridionalis by the presence of a larger lemma and higher number of spikelets.

Conclusion

Analysis of current accessions clearly indicated that there are two distinct types of Australian perennials. Both of them differed genetically from Asian O. rufipogon. One lineage is closely related to O. meridionalis and another to Asian O. rufipogon. The first was presumed to have evolved by divergence from O. meridionalis becoming differentiated as a perennial species in Australia indicating that it represents a new gene pool. The second, apparently derived from Asian O. rufipogon, possibly arrived in Australia later.     

Genetic analysis of a selection experiment on increased body weight and breast muscle weight as well as on limited abdominal fat weight

1. Genetic parameters of body weight (BW), breast meat weight or yield (BRW, BRY) and abdominal fat weight or yield (FTW, FTY) were estimated in males and females originated from an experimental line selected for improving broiler carcase quality and its control line. 2. Mean heritabilities over both sexes of BW, FTW and FTY were 0.43, 0.56 and 0.63 respectively. Those of BRW and BRY were 0.53 and 0.65 respectively. 3. BW was unfavourably correlated with FTW (rg of 0.40) and to a lesser extent with FTY (rg of 0.12). BW was, as expected, highly correlated with BRW (rg 0.77), but a poor correlation was obtained with BRY (rg of 0.15). Selection for more breast yield should not reduce the leanness of the birds, with a genetic correlation between BRY and FTY of -0.15. 4. The variance explained by the maternal effects accounted for a rather small part of the total phenotypic variance (from 3% to 8% according to the trait), but ignoring these effects led to a significant overestimation of the heritabilities (by 11% to 19%). 5. Except for BRY, the heritability estimates differed between sexes, only moderately for BW but more for BRW, FTW and FTY. However, estimated genetic correlations between sexes were high (between 0.94 and 0.99) and in turn heritabilities of sexual dimorphism of the various traits very low (between 0.02 and 0.07). 6. A significant improvement of the genetic level for growth and carcase composition had been obtained in the selected line, with a mean genetic gain per generation of 0.12 sigma g, 0.13 sigma g and -0.30 sigma g for BW, BRY and FTY respectively.     

陕西蓝田核桃低温冻害气候特征分析

采用蓝田国家气象观测站1960-2020年春节核桃萌芽—开花期历史观测资料,以及历年春季低温冻害调查资料,根据冻害气象指标,统计得出冻害主要发生时段集中在3月20日至4月30日,轻度冻害主要集中在3月下旬,而中、重度冻害在4月上旬发生频率最高。利用线性回归及相关分析法对1960-2020年蓝田核桃萌芽、开花期的气温做趋势分析,得知萌芽期和开花期的平均气温、最高气温、最低气温均呈现上升趋势,其中平均气温和平均最高气温上升趋势较为显著。利用MK、MTT和累计距平方法对核桃冻害期平均气温做突变检验,得出核桃萌芽期和开花期平均气温分别在1999年、1997年发生突变。突变后冻害发生风险有所降低。     

论日本茶道与宋代斗茶之渊源

中国的茶与茶文化,对日本的影响甚为深刻,日本茶道的发祥与中国文化的熏陶息息相关。日本茶道与宋代时期流行的茶礼有许多共同点,两国的茶文化也有诸多共通之处。     

松突圆蚧在我国潜在的适生分布区研究

为较准确地预测松突圆蚧在我国潜在的适生分布区域,笔者根据松突圆蚧的生物学、生态学特性以及寄主植物分布状况等,综合分析影响该虫生长发育的主要因子,据此应用地理信息系统分析其潜在的适生分布范围,获得了直观、明晰的松突圆蚧潜在的适生区分布图及风险等级区划图。结果表明,台湾、广东、澳门、香港、广西和福建的大部分及湖南、江西、云南南部地区为松突圆蚧潜在的1级风险区;海南、云南的中部以北地区、湖南与江西的北部、福建东北与西北部、浙江、江苏、安徽、湖北、重庆、贵州、河南、山东和河北中南部、四川东南部、陕西与山西中部以南等地区为松突圆蚧潜在的2级风险区;西藏南部、云南西北部、四川中西南部、甘肃东南部、宁夏、陕西北部、河北西部及辽宁的南部为松突圆蚧的3级风险区。据统计,其潜在分布区域的国土面积占全国国土总面积的41.5%,占我国松树分布面积的90%以上,其中1级风险、2级风险和3级风险区域的国土面积占潜在适生分布区国土总面积的比例分别为18.9%、58.7%和22.4%。     

基于树枝状嵌段共聚物的载药微球的制备及其药物释放表征

为建立一种树枝状共聚物载药微球的制备方法及其药物释放行为的体外评价机制,研究采用实验室自制的4代树枝状大分子引发剂PEG-G4-(OH)32引发己内酯开环聚合,合成了一系列树枝状三嵌段共聚物,并对其结构进行了表征;采用乳液-溶剂挥发法制备了共聚物-紫杉醇载药微球。研究结果显示,以树枝状嵌段共聚物为壁材的载药微球形貌规整,表面平滑,粒径范围为1.92～2.54μm,载药量为15.7%～20.6%;在0～3d的时间里载药微球释药明显,在随后的3～15d的时间里基本呈现线性的零级释放效果。该研究首次采用树枝化聚己内酯的嵌段共聚物制备载药微球,与以线性聚己内酯为壁材制备的载药微球进行了对比,结果表明,前者药物缓释效果更好,具有一定的临床应用前景。     

The problem of meeting dietary protein requirements in intensive aquaculture of marine fish larvae, with emphasis on Atlantic halibut (Hippoglossus hippoglossus L.)

Atlantic halibut (Hippoglossus hippoglossus) achieve a mature gastrointestinal tract approximately 2 months after first feeding (12 °C). The immature digestion may be the reason that compound diets fail to sustain growth and survival in first feeding halibut larvae and in larvae of other marine fish species. On the other hand, larvae fed with live feeds are capable of extraction of sufficient quantities of nutrients to sustain high growth rates. A lower availability of the protein in formulated diets compared with live prey is considered to be an important reason for the low performance of formulated diets. One approach to increase dietary protein availability is supplementation of pre‐digested proteins. Experiments using tube fed individual larvae show that halibut larvae are able to utilize hydrolysed protein more efficiently than intact protein. However, Atlantic halibut in culture did not respond well to dietary supplementation of hydrolysed protein, in contrast to some other species. One reason may be extensive leaching of pre‐hydrolysed proteins from the microparticulate feed. Atlantic halibut are slow feeders and may thus suffer more from nutrient leaching than species eating more rapidly. Feed formulation techniques affect dietary protein leaching, and in this paper, different techniques and their impact on feed properties are described. Microbound diets are most widely used in larval rearing, but show high rates of nutrient leaching. Lipid‐based capsules seem to have the best potential to prevent leaching, however, they are not able to deliver a complete diet. The high need for improvements in larval feed formulation techniques are clearly stated, and some suggestions are given. Among these are production of complex particles, where small lipid‐based capsules or liposomes containing the low molecular weight water‐soluble nutrients are embedded. In such feed particles the water‐soluble molecules are protected from leaching. Techniques for delivery of water‐soluble nutrients that are needed in large quantities, i.e. free amino acids or hydrolysed and water‐soluble protein, remain to be developed.     

泰森多边形与传统四株树法的天然红树林空间结构比较研究

[目的]以漳江口红树林为研究对象,利用泰森多边形和四株树法划分天然红树林林木平面空间分布结构,确定对象木的最邻近竞争木,计算林分空间结构指数,对比分析两种方法的异同,探讨泰森多边形法应用红树林林分空间结构量化的适用性.[方法]设置20 m×20 m样地,每木调查时用钢尺测量横纵坐标,在坐标纸上标记调查木的位置和编号,同...     

补铁对实验性肠炎仔猪肠道结构、功能及体内抗氧化酶活性的影响

利用右旋糖苷硫酸钠(DSS)诱导仔猪肠炎模型,探讨口服铁对患肠炎的仔猪肠道功能和氧化应激参数的影响。试验选取50头21日龄早期断奶仔猪,按体重、性别随机分为5组,每组10头。对照组饲喂基础日粮,饮用自来水,另外4组分别饲喂添加0、0.03%、0.20%和1.00%FeSO4的日粮,饮用含4%DSS的水。结果表明:随着口服铁剂量的增加,肠道微绒毛的损伤逐渐加重。与DSS单独处理组相比,高剂量的铁显著提高了尿中乳果糖/甘露醇的排泄比率,显著降低了血浆中D-木糖的浓度(P<0.05),而低剂量的铁对其没有显著影响。铁的添加显著降低了过氧化氢酶(CAT)和谷胱甘肽过氧化酶(GPx)的活性(P<0.05),而对超氧化物歧化酶(SOD)活性影响不明显。     

How fast can the European eel (Anguilla anguilla) larvae cross the Atlantic Ocean?

The migration duration of European eel ( Anguilla anguilla ) larvae (leptocephali) from the spawning areas in the Sargasso Sea to the European continental shelf remains highly controversial, with estimates varying from 6 months to more than 2 yr. We estimated the fastest migration period and the shortest distance travelled by eel larvae by simulating Lagrangian particles released in the Sargasso Sea and by simulating a range of larval behaviours (fixed-depth drift, vertical diurnal migration and active-depth selection to maximize current velocity). This enabled us to compute (i) a passive drift speed, and (ii) a hypothetic swimming speed needed for European eel larvae to cross the Atlantic in 6 months (i.e., the migration duration estimated from otolith daily growth increments). Our results show that the minimum travel time for an eel larva that is passively drifting was 10 months and 3 days. Active behaviours (vertical diurnal migration and rheotaxis) paradoxically increased the migration period. We found that for leptocephali to cross the Atlantic Ocean in 6 months, they would need to swim a minimum of 3.4 body lengths per second for 8200 km. No larvae have been observed with such swimming capabilities. These results provide evidence that leptocephali cannot cross the Atlantic in 6 months.