胶东海岸的沙生植被

胶东半岛位于山东省东部,地处黄、渤海之滨,陆地海岸线全长1668.58km,占山东省陆地海岸线总长的一半以上。海岸地理位置约当北纬36°15′42″—38°24′00″,东经119°33′00″—122°42′18″之间,属暖温带生     

东北边境地带吸血蠓的区系和生态研究

我国东北吉林省和黑龙江省的边境地带共有18个县区,东起于吉林省珲春县,北止于我国最北端的黑龙江省漠河县,全长约2500km,位于东经122°4′—129°50′,北纬53°—41°25′之间,一般海拔500—1000m,年平均降水量300—700mm,昆虫地理区划属东北区大兴安岭亚区和长白山亚区。多年来,吸血蠓对边境     

大风口水库及石河生态条件与鱼类群落的研究

1987—1989年间对大风口水库及上下游石河的不同河段进行了春夏秋不同季节的生态环境和鱼类群落的调查研究。一、生态条件1.自然概貌和采样段面的选择石河是辽宁西部的一条直接入海的小河,全长67.7km,流域面积431km~2。地理座标为北纬40°10′—40°19′,东经119°50′—120°     

山东白头鹎的一些生态观察

据记载白头鹎Pycnontus sinensis的分布区,北至山东南部郯城(东经118°17′—118°40′、北纬34°251—34°57′)……。1984—1988年作者在山东省泰山(东经117°5′—117°24′、北纬36°5′—36°75′)、徂徕山(东经117°16′—117°20′、北纬36°02′—36°07′)的连续观察和冬季采到的标本,得知此鸟在上述两地为留鸟。常在海拔500米以下的低山一带活动,多停落在树的     

唐山地区的蝗虫种类及其分布

<正> 地理概貌 唐山地区位于河北省东部,东经117°31′—119°19′,北纬38°55′—40°28′。全地区包括10个县3个区和芦台、汉沽两个农场,耕地面积890万亩,境内以小麦、水稻、玉米、高梁、甘     

四川梅花鹿的分布、数量及栖息环境的调查

1992年 7月至 1 999年 8月野外调查发现 ,四川梅花鹿现残存于青藏高原东部边缘山地、岷山山系北段 3块相互完全隔离的区域。铁布分布区 (E1 0 2°46′～ 1 0 3°1 4′、 N33°58′～ 34°1 6′)属四川省若尔盖县铁布自然保护区和占哇乡、降扎乡 ,甘肃省迭部县益哇乡、电尕乡 ,面积 860 km2 ,有鹿 630～ 650只 ;巴西分布区 (E1 0 3°0 8′～ 1 0 3°35′、 N33°33′～ 33°46′)属若尔盖县巴西乡、求吉乡、阿西茸乡、包座乡和九寨沟县的大录乡 ,面积 60 3km2 ,有鹿 1 30～ 1 50只 ;白河分布区 (E1 0 3°59′～ 1 0 4°1 0′、N33°0 5′～ 33°2 0′)属四川省九寨沟县白河自然保护区和农康乡、白河乡、罗依乡、马家乡 ,面积 390 km2 ,有鹿 30～ 45只。高原与高山峡谷的过渡地貌、山地温带气候、森林与灌丛草甸相互镶合的植被 ,加之地域偏僻、人烟稀少 ,当地藏族群众视其为神鹿 ,使上述 3个区域成为四川梅花鹿最后的避难所。     

大兴安岭北部火烧迹地人工更新造林鼠害调查报告

黑龙江省大兴安岭北部的塔河、阿木尔、图强和西林吉4个林业局地处北纬52°30′—54°51′,东经121°51′—125°5′之间,属大兴安岭寒温带明亮针叶林区,寒温带大陆性气候。气候严寒干燥,动植物组成种类贫乏,乔     

中国地衣两新记录

<正>Hebei Province lies in 36°04′-42°40′N and 113°27′-119°50′ E,covering an area of 187,700km2.The hilly area and plateau represent 57% of the total area.The lichen flora of this province is still inadequately known,and only 82 species     

我国金花茶组植物的地理分布

世界产金花茶组植物22种,其中我国20种,特有18种,仅产广西。其分布区在北纬21°30′—23°40′,东经106°40′—108°35′,北界基本上与广西北热带半常绿季雨林、湿润雨林地带北界吻合。该组植物分布于石灰(岩)土的13种,红壤的7种。它们出现的地段比较固定,天然林下,沟谷或溪边处,相对高度10—15米;峰丛圆洼地底部和荫蔽的坡面下部。该组植物个体最多的地区(几何中心)一个在防城县,一个在龙州县;种类最多的地区(最大变异中心)一个也在龙州县,9种,一个在扶绥县,7种。该分布区从南到北分化成六个小分区。其垂直分布一般在海拔700米以下。水平分布种的更替表现为:北纬21°31′为小瓣金花茶等五种;北纬22°10′—22°45′为鼻岗金花茶等八种更替;北纬22°50′为顶生金花茶等三种更替;北纬23°40′为平果金花茶更替。金花茶分布幅度最宽,可由北纬21°31′到22°55′。在土山,东西以东经107°30′为界,以东为金花茶等四种,以西为小瓣金花茶等二种。     

暗腹雪鸡的繁殖及食性

暗腹雪鸡 Tetraogallus himalayensis 属国家保护动物,郑作新等(1978)、沈孝宙等(1963)对其生态仅有零星报道。1984年4月至 1989年 5月,我们在甘肃东大山(39°00′—39°04′N;100°45′—100°51′E.)、冷龙岭(39°34′—38°14′N;101°49′—102°22′E.)和野马山(39°40′—39°50′N;95°15′—95°45′E.)对暗腹雪鸡青海亚种 T.h.koslowi 的繁殖和食性进行了研究。 一、暗腹雪鸡繁殖期的生态分布 在东大山,暗腹雪鸡繁殖期主要分布于海拔 2 400—3 200m的亚高山草甸、山地草原和荒漠草原。其中,山地草原是营巢区,余为觅食区。冷龙岭植被与东大山相似,暗腹雪鸡的生态分布也类似。野马山植被单调,暗腹雪鸡仅分布于山地草原。     

人体肠道病毒组学研究进展

人体微生物组计划开展近10年来,大量的研究显示人体微生物通过各种方式深刻地影响着人体健康。人体肠道内丰富多样的病毒构成了肠道病毒组,是人体微生物组的重要组成部分,和人体健康密切相关。本文综述了近些年国际上人体肠道病毒组研究的最新进展,分别从人体肠道病毒组的组成特征、肠道病毒组-细菌组-人体间的相互作用及其对人体健康的影响、病毒组研究的技术策略及挑战等方面进行了论述,探讨了肠道病毒组在人体疾病预防和治疗领域应用的可行性。     

裸鼠肿瘤动物模型VEGF受体表达及其意义

目的　通过免疫组织化学染色了解flt 1与flk 1 KDR(VEGF的两个高亲和受体 )在人肿瘤细胞皮下接种肿瘤动物模型的血管内皮细胞与肿瘤细胞中的表达。方法　取荷瘤裸鼠皮下接种瘤块 ,漂洗、固定、石蜡连续切片 ,进行两种受体相应免疫组化检测。结果　在 13种荷瘤裸鼠血管内皮细胞及肿瘤细胞中flt 1的阳性率大部分为强阳性或中阳性 ,而只有在荷人胃腺癌MKN 4 5裸鼠的肿瘤细胞中flt 1的阳性率为弱阳性 ,在荷人卵巢癌SKOv3裸鼠的肿瘤细胞中flt 1的表达为阴性。相比较而言 ,在 13种荷瘤裸鼠血管内皮细胞及肿瘤细胞中KDR的阳性率大部分为中阳性或弱阳性 ,并且在荷人肝癌SMMC 772 1裸鼠 ,荷人胃腺癌SPC A1裸鼠 ,荷人高转移肝癌移植瘤裸鼠 ,荷人卵巢癌SKOv3裸鼠的肿瘤细胞中 ,荷人宫颈癌移植瘤裸鼠和荷人胃腺癌MKN 4 5裸鼠的肿瘤细胞中 ,KDR表达为阴性。结论　VEGF受体共同表达于肿瘤血管内皮细胞与肿瘤细胞 ,提示了VEGF与VEGF受体结合作用在肿瘤演化中的重要性 ,为靶向于VEGF受体的基因治疗策略选择裸鼠动物模型提供了参考依据     

Understanding Human Lung Development through In Vitro Model Systems

An abundance of information about lung development in animal models exists; however, comparatively little is known about lung development in humans. Recent advances using primary human lung tissue combined with the use of human in vitro model systems, such as human pluripotent stem cell-derived tissue, have led to a growing understanding of the mechanisms governing human lung development. They have illuminated key differences between animal models and humans, underscoring the need for continued advancements in modeling human lung development and utilizing human tissue. This review discusses the use of human tissue and the use of human in vitro model systems that have been leveraged to better understand key regulators of human lung development and that have identified uniquely human features of development. This review also examines the implementation and challenges of human model systems and discusses how they can be applied to address knowledge gaps.     

Effect of IL-3 and stem cell factor on the appearance of human basophils and mast cells from CD34+ pluripotent progenitor cells.

Hemopoietic stem cell factor (SCF), which is the ligand for the proto-oncogene c-kit receptor (allelic with W locus) and the product of Sl locus of the mouse, has recently been cloned. The human homologue has also been cloned, and recombinant protein (human rSCF) expressed and purified to homogeneity. To determine the effect of human rSCF in the presence or absence of human rIL-3 on human bone marrow-derived mast cells and basophils, human CD34+ pluripotent progenitor cells, highly enriched (greater than 99%) from bone marrow mononuclear cells, were cultured over agarose surfaces (interphase cultures) in the presence of human rIL-3, human rIL-3 and increasing concentrations of human rSCF, or human rSCF alone. Over 3 to 4 wk, human rSCF acted synergistically with human rIL-3 at all concentrations, producing a three- to fivefold increase in total, mast cell, and basophil numbers over human rIL-3 alone when used at 100 ng/ml. The percentage of cell types in the human rIL-3 and human rIL-3 plus human rSCF cultures, however, remained the same, with basophils constituting 18 to 35% of the final cultured cells, and mast cells 3% or less of the final cell number. In the presence of human rSCF alone, the combined total percentage of mast cells and basophils was 0 to 1.0%, the majority of cells being macrophages. Mast cells cultured in human rIL-3 plus human rSCF, but not human rIL-3 alone, were berberine sulfate positive, suggesting the presence of heparin proteoglycans within granules. Electron microscopic examination of cultures supplemented with human rIL-3 and rSCF, but not human rIL-3 alone, revealed that after 3 wk in culture, mast cell granules contained tryptase and exhibited scroll, reticular, and homogeneous patterns as seen previously in CD34+/3T3 fibroblast cocultures. Thus, CD34+ cells cultured in the presence of both human rIL-3 and rSCF give rise to cultures containing increased numbers of basophils and mast cells, with the mast cells by ultrastructural studies showing evidence of maturation although the percentages of basophils and mast cells arising in these cultures remained unchanged.     

Human alpha-globin gene expression following chromosomal dependent gene transfer into mouse erythroleukemia cells.

We have used the genetic marker, adenine phosphoribosyl transferase (APRT), an enzyme known to be on human chromosome 16, to establish a method for the transfer of human α-globin genes into mouse erythroleukemia cells. Mouse erythroleukemia cells devoid of detectable levels of APRT were fused with fractions of human marrow enriched in human erythroid cells. The hybrid cells arising from this fusion were isolated in medium supplemented with aminopterin and thymidine, and used adenine as the sole purine source. This population of hybrid cells was dominated by cells (80%) in which human chromosome 16 was present. Human chromosomes 4, 5 and 6 were also found in these cells. The hybrid cells were then placed in medium supplemented with diaminopurine (DAP), which is lethal for cells containing APRT. Greater than 95% of the DAP-selected hybrid cells lacked human chromosome 16. Cytoplasmic RNA was extracted from the two hybrid cell populations and assayed by molecular hybridization for sequences coding for human α-globin. Carboxymethyl cellulose chromatography was used to study the level of synthesis of human a-globin in the hybrids. The original hybrid cell, which contained a high frequency of human chromosome 16, also contained high levels of human a-globin mRNA and human α-globin chains. Hybrid cells counter-selected in DAP and thus lacking human chromosome 16 were devoid of detectable levels of human APRT, human α-globin mRNA and human α-globin chains. This work shows that transfer of human chromosome 16 into the MEL cell is possible using a chromosomedependent, APRT-mediated method of gene transfer. Using this system in which expression of the human α-globin gene occurs, we were also able to confirm our earlier assignment of the human α-globin gene to human chromosome 16. This system may be of further use in identifying genetic elements governing expression of the human α-globin gene which can be carried with human chromosome 16 as it is donated to the mouse erythroleukemia cell by donor cells of different epigenotypes.     

Unrepaired DNA damage facilitates elimination of uniparental chromosomes in interspecific hybrid cells

Elimination of uniparental chromosomes occurs frequently in interspecific hybrid cells. For example, human chromosomes are always eliminated during clone formation when human cells are fused with mouse cells. However, the underlying mechanisms are still elusive. Here, we show that the elimination of human chromosomes in human–mouse hybrid cells is accompanied by continued cell division at the presence of DNA damage on human chromosomes. Deficiency in DNA damage repair on human chromosomes occurs after cell fusion. Furthermore, increasing the level of DNA damage on human chromosomes by irradiation accelerates human chromosome loss in hybrid cells. Our results indicate that the elimination of human chromosomes in human–mouse hybrid cells results from unrepaired DNA damage on human chromosomes. We therefore provide a novel mechanism underlying chromosome instability which may facilitate the understanding of carcinogenesis.     

人B细胞永生化研究进展

人源单克隆抗体具有免疫原性低、半衰期长等优势,成为了体内应用中不可或缺的生物制剂。人类抗体库为人源单克隆抗体的制备提供了丰富的来源,人B细胞永生化是获得人类抗体库的潜在有效方法,可应用于人源单克隆抗体的制备。由于各平台均有亟待解决的问题,基于人B细胞永生化的抗体制备尚局限在实验室研究阶段,且目前尚缺乏一篇系统综述以明确现有的人B细胞永生化抗体制备平台的优劣及其可行性分析。因此文中就基于人B细胞永生化方法制备人源单克隆抗体的研究展开综述,以期为人源单克隆抗体制备技术的进一步发展提供参考。     

Human heme oxygenase: cell cycle-dependent expression and DNA microarray identification of multiple gene responses after transduction of endothelial cells

The purpose of the present study was to examine the role of human heme oxygenase (human HO-1) in cell cycle progression following exposure to heme or human HO-1 gene transfer and to identify target genes associated with human HO-1-meditated increases in cell cycle progression using cDNA microarray technology. Heme-induced robust human HO-1 expression in quiescent human microvessel endothelial cells cultured in 1% FBS and the levels of human HO-1 expression progressively declined without a change in the cell cyclin. To identify genes regulated by human HO-1 in the cell cycle, human endothelial cells were transduced with a retroviral vector encoded with human HO-1 gene or an empty vector. Transgene expression and functionality of the recombinant protein were assessed by Western blotting, enzyme activity, carbon monoxide, cGMP production, and cell cycle analysis. Human cDNA gene array and quantitative real-time RT-PCR were used to identify both known and novel differentially expressed genes in cells overexpressing human HO-1. Major findings were upregulation of several genes associated with cell cycle progression, including cyclin E and D; downregulation of cyclin-dependent kinase inhibitors p21 and p27, cyclin-dependent kinases 2, 5, and 6, and monocyte chemoattractant protein-1; and upregulation of growth factors, including vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor I (VEGFRI), endothelial growth factor (EGF) and hepatic-derived growth factor (HDGF). These findings identify an array of gene responses to overexpression of human HO-1 and elucidate new aspects of human HO-1 signaling involved in cell growth.     

Effect of recombinant human interleukin 3, granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor on human BFU-e in serum-free cultures

The effects of recombinant human hemopoietic growth factors on early and late human erythroid progenitors (BFU-e and CFU-e) were investigated in serum-free cultures. Recombinant human erythropoietin (rhEpo) induced the formation of not only human CFU-e-derived colonies but also human BFU-e-derived bursts. Recombinant human interleukin 3 (rhIL-3) alone did not induce the formation of human BFU-e-derived bursts and human CFU-e-derived colonies. In the presence of rhEpo, rhIL-3 dose dependently increased the number of bursts stimulated by rhEpo, although rhIL-3 did not have the augmentative effect on human CFU-e growth. On the other hand, rhIL-3 did not stimulate the formation of murine BFU-e-derived bursts, and murine IL-3 did not stimulate the formation of human BFU-e-derived bursts. The results indicated that the burst-promoting activity of IL-3 was species-specific between human and murine cells. Recombinant human GM-CSF (rhGM-CSF) or recombinant human G-CSF (rhG-CSF) failed to induce human burst formation and did not augment the effect of rhEpo on human burst formation. The results of the present study suggest that in vitro, IL-3 can stimulate BFU-e in collaboration with Epo, but GM-CSF and G-CSF do not stimulate BFU-e growth in the presence or absence of Epo.     

Expression of human apolipoprotein A-II and its effect on high density lipoproteins in transgenic mice.

Apolipoproteins A-I and A-II comprise approximately 70 and 20%, respectively, of the total protein content of HDL. Evidence suggests that apoA-I plays a central role in determining the structure and plasma concentration of HDL, while the role of apoA-II is uncertain. To help define the function of apoA-II and determine what effect increasing its plasma concentration has on HDL, transgenic mice expressing human apoA-II and both human apoA-I and human apoA-II were produced. Human apoA-II mRNA is expressed exclusively in the livers of transgenic animals, and the protein exists as a dimer as it does in humans. High level expression of human apoA-II did not increase HDL concentrations or decrease plasma concentrations of murine apoA-I and apoA-II in contrast to what was observed in mice overexpressing human apoA-I. The primary effect of overexpressing human apoA-II was the appearance of small HDL particles composed exclusively of human apoA-II. HDL from mice transgenic for both human apoA-I and human apoA-II displayed a unique size distribution when compared with either apoA-I or apoA-II transgenic mice and contain particles with both these human apolipoproteins. These results in mice, indicating that human apoA-II participates in determining HDL size, parallel results from human studies.