西藏羊湖地区近1.4万年以来孢粉植物群及古气候研究

通过对西藏羊湖地区ZK1和卡拉苏代牙剖面(IP16)的孢粉分析和总有机碳(TOC)、元素含量分析等,建立了羊湖地区近1.4万年以来的孢粉组合带、重建当时的植被类型及古气候演变序列.结果显示:该时期经历了5次植被类型的更替,即草原型→疏林草原型→草原型→疏林草原型→草原型,与之相对应的气候经历了5次波动(2个半旋回),即11220a.B.P.左右的第一气候旋回:由干旱→半干旱半湿润转化;8970a.B.P.左右的第二气候旋回,同样由干旱→半干旱半湿润转化,然后进入半个气候旋回,即干旱气候期,推测今后有可能进入半干旱半湿润气候期.     

西藏羊湖地区近1.4万年以来孢粉植物群及古气候研究

通过对西藏羊湖地区ZK1和卡拉苏代牙剖面（IP16）的孢粉分析和总有机碳（TOC）、元素含量分析等,建立了羊湖地区近1.4万年以来的孢粉组合带、重建当时的植被类型及古气候演变序列。结果显示：该时期经历了5次植被类型的更替,即草原型→疏林草原型→草原型→疏林草原型→草原型,与之相对应的气候经历了5次波动（2个半旋回）, 即11 220 a.B.P.左右的第一气候旋回：由干旱→半干旱半湿润转化;8 970a.B.P.左右的第二气候旋回,同样由干旱→半干旱半湿润转化,然后进入半个气候旋回,即干旱气候期,推测今后有可能进入半干旱半湿润气候期。     

新疆乌伦古湖全新世以来高分辨率的孢粉记录与环境变迁

根据新疆乌伦古湖钻孔剖面高分辨率的孢粉研究,得出全新世以来研究区的气候经历了四个大的阶段：约9．99～7．72cal．kaBP期间,气候温暖干旱;7．72—3．62cal．kaBP,气候由温和偏湿逐渐转向温暖偏干;3．62—1．24cal．kaBP,气候由寒冷干旱逐渐转向寒冷偏湿到温和湿润;1．24cal．kaBP至今,气候总体上温和干旱。在这四个大阶段的气候背景下,还存在8．90cal．kaBP和8．35cal．kaBP左右、3．62—2．80cal．kaBP期间、0．82—0．45cal．kaBP期间和约0．23cal．kaBP时的突然变冷事件。本剖面的孢粉组合在约9．99—7．72cal．kaBP期间反映的是湖区的植被,早期为以芦苇为主的水生植物群落,随后演替成以黑三棱为主的水生植物群落;自7．72cal．kaBP以后,孢粉组合反映的是区域植被,与气候相应的区域植被依次经历了荒漠草原→荒漠→荒漠草原→草原或荒漠草原→草原→荒漠→荒漠草原的多次演替。     

陇中黄土高原末次冰盛期以来的植被演替及其气候响应

末次冰盛期以来,地球系统经历了一次从冷到暖完整的气候旋回,是过去全球变化研究的一个重要时段。本文基于陇中黄土高原会宁硝沟剖面河湖相-水下黄土沉积序列的高分辨率地层孢粉记录,探讨该区末次冰盛期以来的植被演替及其气候响应模式,旨在为黄土高原生态环境建设的战略部署提供科学依据,且对进一步探讨区域气候演化机制、预测未来气候环境变化趋势具有重要意义。硝沟剖面的孢粉记录揭示,末次冰盛期以来该区的植被演替过程为:荒漠草原(寒冷的盛冰期)→针叶疏林/森林草原(逐渐增温的冰消期)→针阔叶混交林为主的森林草原→针阔叶混交林(温暖的盛间冰期)→针叶疏林草原→干草原/荒漠草原;相应的气候变化模式为:冷干→较温湿→较暖湿→暖湿→温凉偏干→较冷干。总体来看,末次冰盛期以来,研究区植被对气候环境变化的响应非常敏感,随着气候的冷暖干湿变化,森林/疏林草原带自东南-西北发生多次进退;区域顶极植物群落为中全新世气候最适宜期发育的针阔叶混交林,研究区早中全新世较长时期都有较大面积的针阔叶混交林发育;晚全新世植被退化为干草原/荒漠草原,一方面可能是气候持续变干的自然响应,另一方面可能也与此时强烈的人类活动对自然森林/草原植被的破坏导致的恶性循环有关。     

黄土高原西部4万多年以来植被与环境变化的孢粉记录

采集甘肃静宁、定西、秦安等地晚更新世晚期以来几个黄土剖面的孢粉样品,分别以晚更新世每个样品分辨率200—300年,全新世20—200年,揭示了黄土高原西部4万多年以来古植被曾经历过草原、森林草原(或疏林草原)、针叶林以及荒漠草原或荒漠几种植被的多次快速变化。在44.2—11kaBP期间,静宁地区植被主要表现为森林和草原成分的相互消长,其中44—29kaBP期间(MIS3)气候以湿润为主,发育针叶林,温度低于现在;23kaBP之后,气候冷干,以稀疏草原为主,在末次盛冰期植被甚至演化为荒漠草原。全新世大部分时间内是以草原或森林草原(或疏林草原)植被为主。在全新世中期,约7.6—5.8kaBP有近1700年时间发育有森林植被,在这个时期当地自然植被覆盖度较高,而草原或疏林草原发育时期植被往往较稀疏,反映气候相对干冷。根据出现的不同类型植物的孢粉浓度及其生态环境特性,研究区早、中全新世,约8.8—5.8kaBP沉积环境较湿润;自3.8kaBP以后气候环境总的变化趋势是逐渐变干,植被开始向草原荒漠化演变。然而,研究区整个全新世气候环境存在多次干湿交替现象,据孢粉记录,其中可能存在11次气候干寒事件。     

3．2MaBP以来河北黄骅地区孢粉地层学与古气候变迁

依据河北省黄骅市八里庄村HB1孔孢粉、古地磁和光释光等资料,发现第四纪以来渤海西岸的古植被演变受气候变化的影响,也受沉积环境的制约.1.6-3.2 Ma BP期间河流发育时期孢粉不丰富;孢粉富集带多出现在湖相地层,而且持续时间短,孢粉贫乏带多出现在河流相沉积地层,持续时间较长;O.8-1.6 Ma BP期间植被以疏林草原为主,局部草原存在,古气候温和偏干.O.13 Ma BP以来,随着明显的古季风变化,孢粉丰富,气候序列分辨率高,可与海洋氧同位素分期对比;11 ka BP以来气候变暖湿润,为针阔叶混交林草原或沼泽草甸植被,3 ka BP之后为海退时期,气候变凉变干,植被由沼泽草甸演变为盐生草甸.尽管该孔是目前沿海平原深孔分析孢粉样品最密的钻孔,但是未能发现连续丰富的孢粉,可能与该孔位于相对较高部位,多与河流沉积环境有关;故而,平原区内并非每一个钻孔皆足以反映整个第四纪孢粉地层学的全貌.     

黄土高原西部地区晚更新世以来古气候环境的演变趋势

本文依据黄土高原西部地区大量的C~(14)年代测定和孢粉组合分析资料,研究了这一地区晚更新世以来古气候环境的演变趋势。指出:兰州、靖远南部至环县(含环县)一线以北地区,现代草原和荒漠草原下的半干旱气候环境可能在晚更新世以来已基本形成,目前更偏干些,但兰州黄河以南阶地距今7600年左右仍属半湿润气候环境。兰州、靖远南部至环县一线以南地区,现代森林草原和草原下的半湿润气候环境是在近7400年以来才逐渐形成的、距今7400年前这一地区的相当一部分山地的古气候可能较现代更湿润些。     

青藏高原全新世花粉记录

全新世青藏高原的花粉记录,反映高原东南部和西北部截然不同的孢粉类型。东南部主要国常绿硬叶种类及潮湿亚热带成分。而西北部几乎没有乔木树种花粉,主要为干旱灌丛和草原成分。文中根据青藏高原２０个湖沼孢粉资料,探讨了青藏高原全新世不同时段、不同地区的植被史及古气候状况。由于高原的特殊大气环流形势,夏半年受西南季风控制,由东南向西北,水份逐渐减弱;冬半年高原面受干冷西风环流影响,致使气候寒冷干燥。全新世植被     

青海湖QH85—14C钻孔孢粉分析及其古气候古环境的初步探讨

本文主要依据青海湖具有~(14)C 年龄数据的 QH 85-14C 钻孔系统孢粉分析资料,将井深4.5m 岩芯所做的孢粉图式从下至上分为五个区域性孢粉带,进而论述了青海湖区11,000年来的植被曾经历了疏林草原(11,000—10,000年 BP)、森林草原(10,000年 BP)、森林(8,000—3,500年 BP)、森林草原(3,500—1,500竿 BP)和疏林草原(1500年前至今),反映的气候序列为凉干→温湿→温干阶段。     

根据孢粉分析论青藏高原西部和北部全新世环境变化

通过对青藏高原西部班公湖钻孔和北部中昆仑山３个湖相剖面的孢粉研究,揭示青藏高原西部和北部地区全新世１万年期间植被的演替和气候变化,西部在全新世早期９９００－７８００ｙｒ．Ｂ．Ｐ．植被由荒漠转为草原,气候好转;中期７８００－３５００ｙｒ．Ｂ．Ｐ．,草原发展,气候较适宜,以７２００－６３００ｙｒ．Ｂ．Ｐ．为高温湿期,５５００ｙｒ．Ｂ．Ｐ．和３５００ｙｒ．Ｂ．Ｐ．出现干旱,晚期从３５００ｙｒ．Ｂ．Ｐ．至今植被为荒漠,气候干旱,其中７００ｙｒ．Ｂ．Ｐ．气候恶化。北部地区全新世时期为荒漠植被,当气候温湿时,蒿和禾本科,莎草科成份增加,藜科减少,气候干旱时则相反,北部全新世的气候分期和干湿波动与西部相近,两地在晚期气候朝干旱化发展。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Comparison of BMI and percentage of body fat of Indian and German children and adolescents

Today, serious health problems as overweight and obesity are not just constricted to the developed world, but also increase in the developing countries (Prentice 2006, Ramachandram et al. 2002). Focusing on this issue, BMI and percentage of body fat were compared in 2094 schoolchildren from two cross-sectional studies from India and Germany investigated in 2008 and 2009. The German children are in all age groups significantly taller, whereas the Indian children show higher values in BMI (e.g. 12 years: Indian: around 22 kg/m2; German: around 19 kg/m2) and in the percentage of body fat (e.g. 12 years: Indian: around 27%; German: around 18-20%) in most of the investigated age groups. The Indian children have significantly higher BMI between 10 and 13 (boys) respectively 14 years (girls). Indian children showed significant higher percentage of body fat between 10 and 15 years (boys) and between 8 and 16 years (girls). The difference in overweight between Indian and German children was strongest at 11 (boys) and 12 (girls) years: 70% of the Indian but 20% of the German children were classified as overweight. In countries such as India that undergo nutritional transition, a rapid increase in obesity and overweight is observed. In contrast to the industrialized countries, the risk of overweight in developing countries is associated with high socioeconomic status. Other reasons of the rapid increase of overweight in the developing countries caused by different environmental or genetic factors are discussed.     

白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较

以白术（Atractylodes macrooephala Koidz.）二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶（POD）的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。     

Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission

The molecular characterisation of species and genotypes of Cryptosporidium and Giardia is essential for accurately identifying organisms and assessing zoonotic transmission. Results of recent molecular epidemiological studies strongly suggest that zoonotic transmission plays an important role in cryptosporidiosis epidemiology. In such cases the most prevalent zoonotic species is Cryptosporidium parvum. Genotyping and subtyping data suggest that zoonotic transmission is not as prevalent in the epidemiology of giardiasis. Molecular characterisation of Cryptosporidium and Giardia is a relatively recent application that is evolving as new genes are found that increase the accuracy of identification while discovering a greater diversity of species and yet unnamed taxa within these two important genera. As molecular data accumulate, our understanding of the role of zoonotic transmission in epidemiology and clinical manifestations is becoming clearer.     

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent.faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium -like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum , shared characteristics with Ent. columbae.
The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol.
Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.