哈尔滨东部城乡土地梯度带的划分及景观结构

以哈尔滨市及东部郊区为对象,重点研究城乡土地梯度带的划分以及造成这种景观分异的内在机制,特别是对镶嵌在城市到乡村之间土地类型的数量变化,研究土地景观结构的特点.研究区范围东西35km,南北16km,在GIS平台上使用TM与SPOT卫星图像划分出东西2.5km,南北16km大小的14条等面积的连续梯度带,根据等面积梯度带的建筑密度和道路密度将研究区域划分为市区、近郊区、远郊区3个梯度区.应用计算机目视判读方法对研究区内进行了土地类型的识别及区划,利用GIS空间分析,计算了各种梯度带的内的不同土地类型的长度、面积.通过这些计算与分析研究了哈尔滨市及东部城乡之间不同梯度带的绿地景观空间结构特点,以绿地建设为核心,辅以城市景观结构及空间格局的特点,分析讨论不同城乡梯度带景观分异的成因.研究表明,区域道路密度和建筑物密度可以在一定程度上反应出城市化进程,据此将哈尔滨及东部城乡划分为市区、近郊区和远郊区;不同梯度区域有其各自的人文景观结构特点和绿地景观结构特点,讨论了造成这种梯度特征的内在机制,并对研究区域未来的城乡绿地及景观建设和可持续发展提出了建议.     

衡阳紫色土丘陵坡地植被恢复对土壤活性有机碳库的影响

为了解植被恢复对土壤活性有机碳库的影响,采用空间代替时间序列方法,对衡阳紫色土丘陵坡地植被恢复对土壤活性有机碳含量和分布进行研究。结果表明,土壤有机碳(SOC)、微生物量碳(MBC)、水溶性有机碳(DOC)、轻组有机碳(LFOC)和易氧化碳(ROC)含量均以乔灌阶段最高(P0.05),随土层加深显著减小(P0.05)。随恢复进程,MBC/SOC、DOC/SOC和ROC/SOC显著增加(P0.05);0~20 cm土层,LFOC/SOC随恢复显著增加(P0.05),而20~40 cm土层,LFOC/SOC的差异不明显(P0.05)。随土层加深,LFOC/SOC显著减小(P0.05),DOC/SOC、MBC/SOC和ROC/SOC逐渐增加(P0.05)。SOC、MBC、DOC、LFOC和ROC间存在极显著正相关关系(P0.01)。各类活性有机碳库与土壤含水量(SWC)、全氮(TN)、碱解氮(AN)和速效磷(AP)呈显著或极显著正相关关系(P0.05或P0.01),与土壤容重(BD)呈极显著负相关关系。因此,植被恢复在一定程度上可提高衡阳紫色土丘陵坡地土壤活性有机碳的形成和积累,增加土壤碳储量。     

传染性软疣病毒（MCV）的电镜观察

传染性软疣病毒（ＭＣＶ）的电镜观察李德忠,肖同浩,武晓华（广州军区武汉总医院电镜室,武汉４３００７０）吴宁（广州军区武汉总医院皮肤科,武汉４３００７０）关键词传染性软疣病毒,病毒形态,电镜观察曾有研究描述ＭＣＶ的发育周期中有８种形态,也有按发育过程将...     

Monitoring vegetation recovery after China’s May 2008 Wenchuan earthquake using Landsat TM time-series data: a case study in Mao County

The Wenchuan earthquake (Richter scale 8) on 12 May 2008 in southwestern China caused widespread ecosystem damage in the Longmenshan area. It is important to evaluate natural vegetation recovery processes and provide basic information on ecological aspects of the recovering environment after the earthquake. To circumvent the weather limits of remote sensing in the Wenchuan earthquake-hit areas, and to meet the need for regional observation analyses, three Landsat TM images pre- and post-earthquake in Mao County were used for analysis. Post-earthquake normalized difference vegetation index (NDVI) values were compared to pre-earthquake values with an NDVI-based index differencing method to determine the extent to which the vegetation was damaged in relation to the pre-earthquake pattern, and the rate of recovery was evaluated. The spatial characteristics of vegetation loss and natural recovery patterns were analyzed in relation to elevation, slope and aspect. The results indicated that severely damaged sites occurred mainly in river valleys, within a range of 1,500?C2,500?m elevation and on slopes of 25?C55°. The distance from rivers, rather than the distance from active faults, controls the damage patterns. After 1?year of natural regeneration, 36?% of the destroyed areas showed a decrease in NDVI value, 28.8?% showed very little change, 19.1?% showed an increase, and 16.1?% also increased with a recovery rate greater than 100?%. Moreover, there is a good correlation between recovery rate and both slope and elevation, but recovery patterns in the damaged area are complicated. Our results indicate that natural recovery in this arid valley is a slow process.     

Birth of calves expressing the enhanced green fluorescent protein after transfer of fresh or vitrified/thawed blastocysts produced by somatic cell nuclear transfer

The present study examined effects of genetic manipulation and serum starvation on in vitro developmental potential of bovine somatic cell nuclear transfer (SCNT) embryos and vitrification on in vivo developmental competence of transgenic SCNT blastocysts. Fetal oviduct epithelial cells (FOECs) were isolated from the oviduct of a Day 147 bovine fetus and transfected with a plasmid (pCE-EGFP-IRES-NEO) containing the enhanced green fluorescent protein (EGFP) and neomycin-resistant (Neor) genes. There were no significant differences (P > 0.05) in cleavage rates or development rates to the blastocyst stage for SCNT embryos derived from FOECs (72.5 and 47.8%, respectively) or transfected FOECs (TFOECs, 73.8 and 47.7%, respectively); nor from serum-fed (73.6 and 47.2%, respectively) or serum-starved (72.7 and 48.3%, respectively) cells. Seventeen of Day 7 GFP-embryos (eight fresh blastocysts and nine vitrified/thawed blastocysts ) were transferred to recipients with one embryo per recipient. Two (25%) recipients were confirmed pregnant at Day 60 in fresh blastocysts group, and three recipients (33%) were confirmed pregnant at Day 60 in vitrified/thawed blastocysts group. Two healthy calves (25%) were obtained from fresh blastocysts and one (11%) from vitrified/thawed blastocysts. Microsatellite analysis confirmed that the three clones were genetically identical to the donor cells. Moreover, PCR and Southern blot demonstrated integration of transgene in genomic DNA of all three cloned calves. Expression of GFP in skin biopsies isolated from transgenic cloned calves and fibroblasts derived from the skin biopsies revealed the activity of EGFP gene, and G418 resistance in vitro of these fibroblasts confirmed the activity of Neor gene. Our results show that genetic manipulation and serum starvation of donor cells (FOECs) do not affect in vitro developmental competence of bovine SCNT embryos, and vitrified transgenic SCNT blastocysts can develop to term successfully.     

Plant-growth-promoting traits and antifungal potential of the Bacillus amyloliquefaciens YL-25

Biological control of plant soil-borne diseases has been shown as an attractive and an environment friendly alternative to chemical fungicides. Different microbial strains have been reported effective in controlling plant pathogens. Among those, Bacillus strains have their own importance. Bacillus amyloliquefaciens strain YL-25, isolated from the rhizosphere of healthy banana plant, was evaluated as bio-organic fertiliser (BIO) for its ability to promote plant growth and suppress Fusarium wilt of banana in pot experiment. The results showed that the application of the BIO containing strain YL-25 significantly promoted the growth of banana plants and decreased the incidence of Fusarium wilt compared to the organic fertiliser and chemical fertiliser (CF). In order to explore the beneficial mechanisms of strain YL-25, experiments were conducted in vitro. The phytohormones including indole-3-acetic acid and gibberellin A3 and stable antifungal compounds three homologous of iturin A were identified in the culture broth of strain YL-25. The strain YL-25 also showed the ability to degrade extracellular phytate in plate experiment. Owing to its innate multiple functional traits and biocontrol activity, the strain YL-25 may be used as plant-growth-promoting rhizobacterium and biocontrol agent against Fusarium wilt of banana.     

Screening of the antigen epitopes of basic fibroblast growth factor by phage display

In order to investigate the epitope of basic fibroblast growth factor (bFGF) and its immunogenicity, the epitopes of bFGF were screened from the phage display library with monoclonal antibody GF22, which can neutralize the bio-activity of bFGF. By three rounds of screening, the positive phage clones with bFGF epitopes were selected, which can effectively block the bFGF to bind with GF22. Sequence analysis showed that the epitopes shared a highly conservative sequence (Leu-Pro-Pro/Leu-Gly-His-Phe/Ile-Lys). The sequence of PPGHFK was located at 22-27 of the bFGF. The specific immuno-response of mouse could be highly induced by phage clones with the epitopes. And the anti-bFGF activity induced by LPGHFK was 3 times higher than the original sequence, which showed that the mimetic peptide LPLGHIK might be used as a tumor vaccine in the prevention and treatment of tumor.     

小型猪急性心肌梗死后心力衰竭模型的构建

目的应用选择性冠状动脉前降支(LAD)球囊闭塞结合微血栓微球混悬液灌注方法造成心肌缺血坏死,探索建立稳定存活的小型猪急性心肌梗死(AMI)后心力衰竭(HF)动物模型。方法选择中国五指山小型猪18头,行冠脉造影后沿血管送球囊至LAD中段,依次扩张球囊阻断前向血流1、2、5 min,每次间隔60 s,然后扩张球囊堵闭血流120 min。再以4F导管超选LAD,行微血栓微球混悬液分次注入,间隔10 min重复注射,TIMI心肌灌注分级(TMPG)2级和左室舒张末压(LVEDP)15 mm Hg时停止注射,同时监测心电图及应用漂浮导管监测有创血流动力学参数。并行pigtail导管测量(LVEDP)的变化,待LVEDP稳定在15~18 mm Hg之间后结扎血管,并加压包扎。监测心肌坏死标志物(cTnI和CK-MB)变化。分别于制模前,制模后第1天、7天、14天行心脏超声检查,制模第14天复查有创血流动力学检查,并行心脏病理检查,认定和评价模型的成功率、稳定性和可重复性。结果制模14 d后共有15头小型猪成活,心电图、心肌坏死标记物、病理检查均符合AMI病理生理过程。其中14头小型猪达到动物模型标准【肺毛细血管楔压(PCWP)18 mmHg和心输出量(CO)下降30%以上】,模型成功率为77.78%。制模后第14天PCWP明显升高(P0.01),CO平均下降50.76%;左室射血分数(LVEF)明显降低(P0.01)。病理检查显示心肌梗死面积占左心室面积的25.4%~34.9%。结论球囊闭塞结合微血栓微球混悬液灌注构建小型猪急性心肌梗死后心力衰竭模型具有闭胸、高成功率、稳定和重复性好等优点,较药物、冠状动脉结扎和起搏诱导的心力衰竭模型更接近临床病理生理学特点。     

Imaging and measuring the rituximab-induced changes of mechanical properties in B-lymphoma cells using atomic force microscopy

The topography and mechanical properties of single B-lymphoma cells have been investigated by atomic force microscopy (AFM). With the assistance of microfabricated patterned pillars, the surface topography and ultrastructure of single living B-lymphoma cell were visualized by AFM. The apoptosis of B-lymphoma cells induced by rituximab alone was observed by acridine orange/ethidium bromide (AO/EB) double fluorescent staining. The rituximab-induced changes of mechanical properties in B-lymphoma cells were measured dynamically and the results showed that B-lymphoma cells became dramatically softer after incubation with rituximab. These results can improve our understanding of rituximab’effect and will facilitate the further investigation of the underlying mechanisms.     

基于i-Tree模型的城市森林经济效益评估

城市森林的生态服务功能对改善城市环境质量具有重要作用,如何量化这些生态服务功能是使城市森林发挥最大效益的一个重要前提.随着科学的发展,对城市森林经济效益评估的量化方法已由传统的CTLA法、Burnley法、碳税法、造林成本法等发展到模型测算法.本文介绍的i-Tree模型是由美国林务局(USDA Forest Service)于2006年开发的城市森林效益评估软件,具有许多其他模型如CITY green模型等不可替代的优势,在国际城市森林研究中已得到了广泛的应用,但国内尚未推广.本文主要阐述和评价了模型中UFORE和STRATUM两个主要模块的研究及应用进展,通过作者在国内的应用实践,讨论了该模型在中国的应用前景及存在的主要问题,为城市森林管理提供科学依据.