拥挤试剂PEG2000对不同拓扑结构类弹性蛋白相变的影响

类弹性蛋白（Elastin-like polypeptides,ELPs）是属于弹性蛋白中的一种且具有温控性的生物大分子,本文研究拥挤试剂对不同拓扑结构ELPs相变温度的影响,利用温控-紫外分光光度计研究其相变特性,结果发现,随着PEG2000浓度的增加,T-E-F的相变温度下降11.9~17.1℃;在固定Tadpole-like-E浓度下,随着PEG2000浓度的增加,Tadpole-like-E的相变温度降低11.5~16℃,其中,25 μmol/L的Tadpole-like-E其相变速度缓慢;ELPs浓度越大,其相变温度降低愈大,且PEG2000影响ELPs相变温度的趋势与ELPs的拓扑结构关系不大。另外,在简单的PBS缓冲溶液中加入PEG2000,可以使E-C在浓度＜0.5 mol/L的Na2CO3中发生相变,且随着PEG2000浓度的增加,E-C相变温度逐渐降低。本研究为今后ELPs在复杂体系的应用提供前期的基础研究。     

1990—2015年三江平原生态功能区水禽栖息地适宜性动态

作为国际重要湿地,三江平原生态功能区是重要的水禽栖息地.随着人类活动干扰、土地利用和全球气候变化,栖息地适宜性逐渐引起生态学家的重视.本文以Landsat TM/ETM+/OLI和HJ-1B为遥感信息源,采用面向对象分类方法提取土地覆被空间信息;采用综合熵值法和层次分析法确定水源状况(湖泊和河流密度)、干扰条件(居民地和道路密度)、遮蔽物(土地覆被类型和坡度)和食物丰富度(NDVI)等因子的权重;根据水禽栖息地适宜性评价系统获得三江平原生态功能区1990、2000、2010和2015年水禽栖息地适宜性结果,并分析其时空分布和变化特征及驱动因素.结果表明: 近25年间,三江平原生态功能区水禽栖息地适宜性最好区域面积减少3.2%,主要由于湿地开垦和退化;适宜性最好区域空间分布特征明显,主要分布于黑龙江、挠力河、乌苏里江、穆棱河以及兴凯湖等水补给充足的沿岸区域.适宜性良好的区域主要分布在饶河县,到2010和2015年,虎林县和抚远县也变为适宜性良好区域的重要分布区,主要由于该区水田面积大幅增加.适宜性一般区域分布较零散,其面积先增加后减少.适宜性差的区域面积在1990—2000年间增加6.7%,2000—2015年间减少3.1%.土地覆被变化是水禽栖息地适宜性等级变化的最重要影响因素;人口和经济增长以及气候的变干、变暖使水禽栖息地适宜性降低;保护区的建立使水禽栖息地得到有效保护.     

健康教育对心脑血管疾病终点事件发生的干预效应

通过健康教育干预探讨对心脑血管疾病发生之影响,为心脑血管疾病的防治工作提供理论依据。方法：从2000年到我院集中体检的大于50岁以上的在职和离退休干部4000人中,抽出资料完整并符合本次研究纳入标准者2000人,随机分为健康干预组和一般治疗对照组各1000人。其中干预组1000人中,高血压480人,高脂血症413人,高血压合并高脂血症107人;对照组1000人中,高血压478人,高脂血症423人．高血压合并高脂血症100人。两组均以高血压、高脂血症作为最主要的危险因素进行健康教育干预。健康教育干预组患者分别建立健康档案,制定系统的健康教育干预措施并组织实施,定期随访：一般治疗对照组患者将体检结果通知本人后,由其在门诊接受健康教育和治疗,对健康教育和治疗方法不作强制性规定。连续观察五年,比较两组五年间心脑血管疾病的发生情况（即以发生AMI／心绞痛、脑出血、脑血栓形成等心脑血管疾病的终点事件为评价标准）。结果：健康教育干预组病情控制良好,发生上述心脑血管疾病终点事件比危险因素对照组明显减少（急性心肌梗塞发生率为2．0％比3．4％,脑血栓发生率为4．3％比7．5％,TIA为2．1％比2．9％）,P〈0．01。结论：对存在心脑血管疾病危险因素者积极开展健康教育干预,可起到控制疾病进一步发展,减少心脑血管疾病终点事件的发生。     

An in vitro assessment for evaluating the efficiency of β-d-mannuronic acid (M2000) in myelodysplastic syndrome

β-d -Mannuronic acid (M2000), a novel non-steroidal anti-inflammatory drug (NSAID) with immunosuppressive properties, has been previously shown to exhibit potential therapeutic effects on autoimmune diseases. Immunosuppression therapy has been a standard approach for myelodysplastic syndrome (MDS) for many years. We evaluated the effect of M2000 on isolated peripheral blood mononuclear cells (PBMCs) from patients with MDS. The PBMCs were isolated from 13 patients with MDS and 13 normal donors. The cells were then treated with low, moderate, and high doses of M2000 and diclofenac as a control group. The level of interleukin (IL)-6, tumor necrosis factor alpha (TNF-α), IL-3, granulocyte colony-stimulating factor (G-CSF) gene expression and the serum level of IL-6 and TNF-α production were evaluated by real-time polymerase chain reaction and enzyme-linked immunosorbent assay methods, respectively. Our findings indicated a significant reduction in the production of IL-6 and TNF-α as inflammatory cytokines. Furthermore, the level of G-CSF gene expression was significantly increased. In conclusion, M2000, a newly designed NSAID, has a remarkable effect on isolated PBMC in patients with MDS, which might bring a potential hope for its oral administrations in these patients.     

Molecular analysis of deletions in human chromosome 3p21 and the role of resident cancer genes in disease.

Epithelial cancers inflict a heavy human and social burden. It was estimated [Tyczynski JE, Bray F, Parkin DM. Lung cancer in Europe in 2000: epidemiology, prevention, and early detection. Lancet Oncol 2003;4:45-55 (Review)] that in Europe, in the year 2000, 347 000 persons died of lung cancer alone, the deadliest cancer disease. Loss of heterozygosity and large homozygous deletions of the human chromosome region 3p21 are especially frequent in epithelial cancers of several organs. In fact, 3p21 is a very peculiar region of the genome harbouring, tightly clustered, several types of cancer-causing genes (CCG) (Lerman MI, Minna JD. The 630 kb lung cancer homozygous deletion region on human chromosome 3p21.3: identification and evaluation of the resident candidate tumour suppressor genes. The International Lung Cancer Chromosome 3p21.3 Tumor Suppressor Gene Consortium. Cancer Res 2000;60:6116-33). Current results show that, unlike it was thought initially, many tumour suppressor genes (TSG) are located close by even in small genomic regions. They may be involved, perhaps with varying role, in different types of tumour, and may be influenced by the genetic background of different human populations as well as by environmental pollutants (cigarette smoking, professional exposure). This review will discuss methods of molecular analysis of genomic deletions to uncover CCG at 3p21, will summarize the present knowledge regarding the TSGs located in this region, and will describe a possible model of epithelial cancer pathogenesis.     

野生扬子鳄种群及栖息地现状研究

1999年7～8月及2000年8～9月,利用GPS、激光测距仪等,采用夜间灯光照射计数方法,对 有野生扬子鳄(Alligator sinensis)存在的安徽省宣州、泾县、广德、郎溪、南陵等5 县市的26个地点进行了调查,包括扬子鳄国家级自然保护区的13个指定保护点。结果发现： 目前野生扬子鳄主要生存在第一类栖息地（1999年50.7%、2000年40.0%）,面积为17.38 hm²;其他两类栖息地的野生扬子鳄分布比率较小（各为1999年24.0%、2000年30.9%、1999 年25.3% 、2000年29.1%）,面积分别为22.04hm²、19.03hm²。两年的平均生态密度分别为1.28条/hm²和1.79条/hm²,野生扬子鳄种群数量为145条。其种群已明显分为至少18个数 量不等且相互隔离的地方种群。建议恢复足够大的栖息地,并放饲养鳄于其中以重新 建立有效野生种群。     

The effects of temperature,salinity, concentration and PEGylated lipid on the spontaneous nanostructures of bicellar mixtures

The self-assembling morphologies of low-concentration (mostly 1 and 10 mg/mL) bicellar mixtures composed of zwitterionic dipalmitoyl (di-C₁₆) phosphatidylcholine (DPPC), dihexanoyl (di-C₆) phosphatidylcholine (DHPC), and negatively charged dipalmitoyl (di-C₁₆) phosphatidylglycerol (DPPG) were investigated using small angle neutron scattering, dynamic light scattering and transmission electron microscopy. A polyethylene glycol conjugated (PEGylated) lipid, distearoyl phosphoethanolamine-[methoxy (polyethyleneglycol)-2000] (PEG2000-DSPE), was incorporated in the system at 5 mol% of the total lipid composition. The effects of several parameters on the spontaneous structures were studied, including temperature, lipid concentration, salinity, and PEG2000-DSPE. In general, nanodiscs (bicelles) were observed at low temperatures (below the melting temperature, T_M of DPPC) depending on the salinity of the solutions. Nanodisc-to-vesicle transition was found upon the elevation of temperature (above T_M) in the cases of low lipid concentration in the absence of PEG2000-DSPE or high salinity. Both addition of PEG2000-DSPE and high lipid concentration stabilize the nanodiscs, preventing the formation of multilamellar vesicles, while high salinity promotes vesiculation and the formation of aggregation. This study suggests that the stability of such nanodiscs is presumably controlled by the electrostatic interactions, the steric effect induced by PEG2000-DSPE, and the amount of DHPC located at the disc rim.     

Seasonal Prevalence of Mosquitoes Collected from Light Traps in Korea (1999-2000)

ABSTRACT Adult mosquito collections were conducted from 1999 through 2000 at 29 US military installations located in six provinces in the Republic of Korea (ROK). Adult mosquitoes were collected in New Jersey light traps from 15 May to 15 October each year. Adult mosquito surveillance was conducted to determine the appropriate time for pesticide applications at each of the Army installations. A total of 68,051 and 62,526 adults were collected in 1999 and 2000 respectively, comprising 53,983 (79.3%) females and 14,068 (20.7%) males in 1999, and 50,274 (80.4%) females and 12,252 (19.6%) males in 2000. A total of 19 species from 7 genera were collected. The most common species collected were Anopheles sinensis (34.2%), Culex tritaeniorhynchus (29.4%), Aedes vexans nipponii (18.2%) and Culex pipiens (16.8%). Anopheles sinensis were collected at the same level while Culex tritaeniorhynchus decreased by 6.2% in 2000. The weekly population densities for some species were variable for each of the years, apparently as a result of changing weather conditions.     

Identification of inter simple sequence repeat (ISSR) markers associated with seed size in wheat

The feasibility of identifying inter-simple sequence repeat markers associated with seed weight in hexaploid wheat was tested using 113 recombinant inbred lines developed by the single-seed descent method, from a cross between Rye selection111, an Indian genetic stock obtained through the introgression of genes for bold seed size from rye, and Chinese Spring having small seed size. Three markers were associated with low seed size with gene effects of 14.8%, 9.5%, and 6%, while four markers with contributions of 8%, 4.66%, 2.92% and 2.61% were found to be linked to high seed size, together contributing 31% of the phenotypic variance in seed size. Nulli-tetrasomic and di-telosomic analysis revealed the presence of three low seed size QTL-associated markers on three chromosomes, 6BL, 2DL, and 1DS respectively. This study clearly demonstrates that ISSRs are highly useful for finding markers associated with major and minor genes controlling agronomically important traits in wheat. Received: 24 February 2000 / Accepted: 31 March 2000     

Changes in the structure of xyloglucan during cell elongation

Xyloglucans were isolated by sequential extraction of the cell walls of pea (Pisum sativum L. cv. Alaska) with a xyloglucan-specific endoglucanase and KOH. The xyloglucan content and xyloglucan-oligosaccharide composition were determined for fractions obtained from the elongating and non-elongating segments of pea stems grown in the light and in darkness. The results were consistent with the hypothesis that regulated growth of the cell wall depends on xyloglucan metabolism. Furthermore, the characterization of xyloglucan extracted from leaves of light-grown pea plants indicates that xyloglucan metabolism is tissue specific. Changes in xyloglucan subunit structure observed in elongating stems are consistent with the in muro realization of a metabolic pathway that was previously proposed solely on the basis of the in vitro activities of plant glycosyl hydrolases. Received: 21 May 2000 / Accepted: 7 June 2000     

Genetic analysis of kernel hardness in bread wheat using PCR-based markers

In wheat, kernel hardness is a complex genetic trait involving various directly and indirectly contributing components such as kernel hardness per se, protein content, hectolitre weight and 1,000-kernel weight. In an attempt to identify DNA markers associated with this trait, 100 recombinant inbred lines (RILs) derived from a cross between a hard grain land-race, NP4, and a soft grain variety, HB 208, were screened with 100 ISSR and 360 RAPD primers. Eighteen markers were assigned to seven linkage groups covering 223.6 cM whereas 11 markers remained unlinked. A multiple-marker model explained the percentage of phenotypic variation for kernel hardness as 20.6%, whereas that for protein content, hectolitre weight and 1,000-kernel weight was 18.8%, 13.5% and 12.1%, respectively. Our results indicate that phenotypic expression of kernel hardness is controlled by many QTLs and is interdependent on various related traits. Received: 25 July 2000 / Accepted: 24 November 2000     

Physiological basis of reduced Al tolerance in ditelosomic lines of Chinese Spring wheat

Aluminum tolerance was assessed in the moderately Al-tolerant wheat (Triticum aestivum L.) cultivar Chinese Spring and a set of ditelosomic lines derived from Chinese Spring. Three ditelosomic lines lacking chromosome arms 4DL, 5AS and 7AS, respectively, exhibited decreased Al tolerance relative to the euploid parent Chinese Spring based on reduced root growth in Al-containing solutions. The physiological basis of the reduced Al tolerance was investigated. Measurements by inductively coupled argon plasma mass spectroscopy of root apical Al accumulation demonstrated that two of these three lines had a decreased ability to exclude Al from the root apex, the site of Al phytotoxicity. As Al-induced malate exudation has been suggested to be an important physiological mechanism of Al tolerance in wheat, this parameter was quantified and malate exudation was shown to be smaller in all three deletion lines compared with Chinese Spring. These results suggest that the decreased Al tolerance in at least two of the three ditelosomic lines is due to the loss of different genes independently influencing a single Al-tolerance mechanism, rather than to the loss of genes encoding alternative Al-tolerance mechanisms. Received: 3 July 2000 / Accepted: 9 August 2000     

Fracture mechanics of the cell wall of Chara corallina

Previous mechanical studies using algae have concentrated on cell extension and growth using creep-type experiments, but there appears to be no published study of their failure properties. The mechanical strength of single large internode cell walls (up to 2 mm diameter and 100 mm in length) of the charophyte (giant alga) Chara corallina was determined by dissecting cells to give sheets of cell wall, which were then notched and fractured under tension. Tensile tests, using a range of notch sizes, were conducted on cell walls of varying age and maturity to establish their notch sensitivity and to investigate the propagation of cracks in plant cell walls. The thickness and stiffness of the walls increased with age whereas their strength was little affected. The strength of unnotched walls was estimated as 47 ± 13 MPa, comparable to that of some grasses but an order of magnitude higher than that published for model bacterial cellulose composite walls. The strength was notch-sensitive and the critical stress intensity factor K _1c was estimated to be 0.63 ± 0.19 MNm^−3/2, comparable to published values for grasses. Received: 4 April 2000 / Accepted: 21 July 2000     

脊胸露尾甲生物学特性的观察

通过室内饲养观察及实地调查,明确了脊胸露尾甲年发生规律等基本生物学特性。该虫世代重叠现象明显,每代历期约33～38d,其中产卵前期平均68d,卵历期平均32d,幼虫期平均179d,蛹期平均75d。成虫产卵明显受性比的影响,雌雄性比小时,雌虫产卵量增多。     

雄性小熊猫粪便中睾酮水平的变化与繁殖周期的关系

1999 年12 月至2000 年9 月, 使用放射免疫分析法, 测定了成都动物园和成都大熊猫繁育研究基地的4 只雄性小熊猫粪样中睾酮水平变化情况, 同时对其行为进行了观察。研究结果表明, 雄性粪样中睾酮水平在繁殖期(12 月～3 月) 显著高于非繁殖期(4 月～9 月) (P < 0.01) , 且睾酮水平变化与繁殖行为密切相关。在非繁殖期,雄性小熊猫的睾酮水平处于基础的较低水平时, 其繁殖行为如蹭阴、舔阴、舔标记物和咩叫等几乎没有发生或很少发生; 而在繁殖期, 雄性小熊猫的睾酮水平明显升高, 这些繁殖行为频繁发生。以上结果说明, 睾酮是调节雄性小熊猫繁殖行为季节性变化的生理因子。     

大白×梅山杂交组合肉质性状的数量性状位点定位分析

为寻找影响猪肉质数量性状基因位点的染色体区域 ,以 3头英系大白公猪和 7头梅山母猪建立F2 资源家系。随机选留 14 7头F2 代个体 (1998年 81头 ,2 0 0 0年 66头 ) ,经检测均获得肉质性状表型数据。对资源家系内的所有个体位于染色体 1、2、3、4、6和 7上的 48个微卫星位点进行扩增。利用线性模型最小二乘法分别对各年度及两年综合后的肉质性状进行数量性状位点 (QTL)区间定位 ,利用置换法确定显著性阈值。研究结果表明 :在 2 0 0 0年群体中 ,猪 4号染色体 (SSC4)上定位了肌内脂肪QTL ,达到染色体极显著水平 (P <0 0 1)和基因组显著水平 (P <0 0 5) ,解释表型变异为 5 2 4% ,梅山猪具有增加肌内脂肪QTL ;两年度群体综合后 ,在上述 4号染色体同一区间 ,肌内脂肪QTL接近染色体显著水平 ;股二头肌pH值和半棘肌pH值QTL分别定位在SSC1和 3上 ;在 1998年和 2 0 0 0年群体中分别发现 1个和 3个达染色体显著水平 (P <0 0 5)的系水力QTL ;在 1998年群体中 ,肌肉含水量QTL位于SSC6;两年综合群体中 ,SSC2、6和 7上定位了肌肉含水量QTL ,达到染色体显著水平 ,含水量QTL均有印迹效应 ,梅山和大白猪各有增效基因     

Fatty acid composition of brown adipose tissue in genetically heat-tolerant FOK rats

The phospholipid fatty acid composition of brown adipose tissue (BAT) was examined in inbred heat-tolerant FOK rats and compared with that in conventional Wistar rats not previously exposed to heat. The FOK rats showed higher unsaturation states, as indicated by higher levels of polyunsaturated fatty acids and a higher unsaturation index and polyunsaturated fatty acids/saturated fatty acids ratio. This higher level of unsaturation was characterized by the higher amount of polyunsaturated fatty acids such as linoleic acid, arachidonic acid and docosahexaenoic acid. It may be concluded that the increased docosahexaenoic acid level in BAT phospholipids brings about the hyperplasia of BAT, causing an enhancement of its in vivo thermogernic activity as well as the systemic non-shivering thermogenesis observed in heat-tolerant FOK rats. Received: 17 May 2000 / Revised: 21 August 2000 / Accepted: 21 September 2000     

Genetic mapping of expressed sequence tag polymorphism (ESTP) markers in loblolly pine (Pinus taeda L.)

The development and mapping of genetic markers based upon expressed sequence tag polymorphisms (ESTPs) in loblolly pine (Pinus taeda L.) are reported. The new markers were generated by PCR-amplification of loblolly pine genomic DNAs with primers designed from sequenced cDNAs. The cDNA libraries were constructed from RNAs expressed in the needles of loblolly pine seedlings or in the xylem from young trees. DNA polymorphisms were identified by analyzing the amplified products for differences in fragment size or restriction sites, or by examining mobility differences using denaturing gradient gel electrophoresis (DGGE). DGGE revealed more DNA polymorphisms than the other two methods. Fifty six ESTPs were mapped using either of two mapping populations and positioned onto a loblolly pine consensus genetic map. Unlike many other markers commonly used in forestry, ESTPs can be used as orthologous markers for comparative mapping, to map genes of known function, or to identify candidate genes affecting important traits in loblolly pine. Received: 10 April 2000 / Accepted: 13 July 2000     

呼中林区森林景观的历史变域模拟及评价

在大兴安岭地区呼中区,将物种的年龄和分布信息进行随机化处理后,应用空间直观景观模型LANDIS对森林景观进行长时间(2500a)模拟,取物种演替稳定时间段作为模拟历史变域的数据来源.分别在景观水平和年龄类型水平上利用景观指数空间分析、主成分分析和核密度估计方法分析景观格局历史变域的模拟结果,并在二维空间坐标内,将研究区1990年、2000年森林景观特征与之比较.结果表明,各树种面积比例在模拟900a后都达到稳定状态,可作为无干扰条件下森林景观特征的历史变域;由于长期采伐,研究区1990年景观的斑块面积和破碎化程度都偏离了该历史变域,其中,过熟林偏离最明显,其斑块面积远小于历史变域,破碎化程度非常严重;虽然1990年后的采伐管理方案比之前的更为合理,但2000年的森林景观仍旧继续偏离历史变域.