Application of the principles of enzyme kinetics to clonal growth rate assays: an approach for delineating interactions among growth promoting agents.

The interaction of mitogenic factors on a single cell type and the comparative activity of a given factor in diverse cell types have been studied by applying the principles of Michaelis-Menten kinetics to clonal growth data. Such comparisons are facilitated by derivation of two parameters; Km mitogen, the mitogen concentration that gives half-maximal clonal growth and a theoretical maximal growth rate, RMAX T. Both parameters are analogous to the Km and VMAX as applied to enzymatic reactions. Use of these parameters permits meaningful comparisons between cells with different growth rates. Using kinetic analysis of dose-response data, we found that normal human epithelial cells require 200 times more fetal bovine serum protein (FBSP) than a malignant line to multiply at their respective half-maximal rates. Further, the Km FBSP of normal cells was reduced to that of the malignant line by the inclusion of growth factors (EGF or FGF, and hydrocortisone) in the medium. On the other hand, even though greater levels of serum were required when growth factors and hydrocortisone were not present, their inclusion did not alter RMAX T. Interactions between mitogenic factors were shown to be unidirectional. Although EGF reduced the Km FBSP, FBSP did not change the Km EGF. The same type of analysis revealed that hydrocortisone, which potentiated the mitogenic activity of EGF did not change the Km EGF. Kinetic analysis of cell growth should prove useful in studies on the relation between growth and tumor promotion as well as in the evaluation of growth-inhibiting chemotherapeutic agents.     

不同立地条件对济南千佛山侧柏林生长影响的初步研究

侧柏(Platycladus orientalis Franco,英文名为Oriental arborvitae)为喜暖旱中生乔木。侧柏林在群落分类上属于温性针叶林植被型、侧柏林群系组、侧柏林群系。侧柏是我国主要造林树种之一,广泛分布于全国各地,作为中心分布区之一的山东省。     

The role of polypeptide growth factors in phenotypic transformation of normal rat kidney cells

A serum-free assay has been established for studying the role of polypeptide growth factors in inducing loss of density-dependent inhibition of growth of normal rat kidney (NRK) cells. The process has been characterized by measuring the time course of [3H]thymidine incorporation into confluent, quiescent NRK cultures stimulated by defined polypeptide growth factors, in combination with cell counting studies, increases in DNA content, and cell cycle analysis by means of a fluorescence-activated cell sorter. It is shown that none of the growth factors tested (epidermal growth factor, platelet-derived growth factor, transforming growth factor-beta, and retinoic acid) is able to induce loss of density-dependent inhibition of growth by itself, but strong synergism was observed when combinations of growth factors were tested. None of the above factors was found to be essential, however, since any combination of three of the above four growth factors strongly induced the process. Strong parallels were observed between the growth factor requirements for inducing loss of density-dependent inhibition of growth under serum-free conditions and the requirements for induction of anchorage-independent proliferation under growth factor-defined assay conditions. This indicates that most likely the same cellular processes underlie these two aspects of phenotypic transformation, although data indicate that anchorage-independent proliferation may be a more restricted property of phenotypic transformation than loss of density dependence of proliferation. It is concluded that phenotypic transformation of NRK cells does not require specific polypeptide growth factors, but reflects the ability of these cells to respond to multiple growth factors.     

High-affinity binding of basic fibroblast growth factor and platelet-derived growth factor-AA to the core protein of the NG2 proteoglycan.

NG2 is a transmembrane chondroitin sulfate proteoglycan that is expressed by immature progenitor cells in several developmental lineages and by some types of malignant cells. In vitro studies have suggested that NG2 participates in growth factor activation of the platelet-derived growth factor-alpha receptor. In this study the ability of recombinant NG2 core protein to interact with several different growth factors (epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF)-AA, PDGF-BB, vascular endothelial growth factor (VEGF)165 and transforming growth factor (TGF)-beta1) was investigated using two different assay systems: enzyme-linked immunosorbent assay-type solid-phase binding and an optical biosensor (BIAcore) system. High-affinity binding of bFGF and PDGF-AA to the core protein of NG2 could be demonstrated with both types of assays. Using both the BIAcore software analysis program and nonlinear regression analysis of the solid phase binding data, KD values in the low nanomolar range were obtained for binding of each of these growth factors to NG2. The results further indicate that NG2 contains at least two binding sites for each of these two growth factors. PDGF-BB, TGF-beta1, VEGF, and EGF exhibited little or no binding to NG2 in either type of assay. These data suggest that NG2 can have an important role in organizing and presenting some types of mitogenic growth factors at the cell surface.     

陕北南部侧柏生长与生态因子的关系

分别用灰色关联分析、数量化方法Ｉ及多元逐步筛选回归方法分析了陕北南部气候、地形及土壤肥力与侧柏生长的关系,并对不同林分中侧柏的生长做了讨论。结果表明,气候因子中的降水量,地形因子中的坡位对侧柏径生长的影响很大,而坡度的影响主要表现在对侧柏高度生长的影响上。土壤含水量和有机质含量在侧柏林、松柏混交林阶段与侧柏径生长呈显著正相关,栎类树对侧柏生长有显著抑制作用,而松类树对无明显影响。     

山东侧柏林生长生态特性的数值分析

应用多元分析方法研究了26个生态因子对山东侧柏林的3个生长指标的影响．结果表明影响林分生长的主要因子是：温度、土壤厚度、海拔和密度,排出了生态因子对林分生长指标的重要性序列,给出了林分生长指标的优化数学模型．     

中国串珠藻科植物地理分布及与环境因子的关系

研究以中国串珠藻科Batrachospermaceae的串珠藻属Batrachospermum、熊野藻属Kumanoa和西斯藻属Sheathia植物样本的经纬度和一些重要环境因子数据为研究材料,采用方差分析、相关分析、主成分分析和线性判别分析的方法,分析这些环境因子对3个属的地理分布影响及3个属地理分布和生长环境的差异...     

Associations between lake phytoplankton community and growth factors — a canonical correlation analysis

Canonical correlation analysis was used to study the associations between the most prevalent phytoplankton species and nine physical and chemical growth factors in a polyhumic Finnish lake. The analysis was made (a) to the ten species with the greatest mean biomass in the data over one growth season and (b) to the ten species providing the greatest canonical correlation with the growth factors. The latter species were detected using an exchange type procedure. The analysis showed strong associations within phyla. Especially the most problematic phylum with respect to the use of the lake, the cyanobacteria, had a pronounced mutual association, as they correlated negatively with the N/P ratio as positively with phosphorus.     

Radial growth response of major conifers to climate change on Haba Snow Mountain,Southwestern China

Climate change has an inevitable impact on forest ecosystems, to better understand the influence of climate change on forest growth, we analyzed the growth response of four major conifers to climate on Haba Snow Mountain in central Hengduan Mountains. Tree ring samples were taken from four species at their upper distributional limits, and residual chronologies were developed by using tree ring width data. Response function and redundancy analysis were taken to reveal the key climatic factors affecting tree growth and moving interval analysis was applied to detect the stability of growth-climate relationships. The results showed that previous November temperature, precipitation in current February, current May and current June were common factors affecting the radial growth of the studied species. Abies georgei was mainly influenced by the temperature in previous November. The photothermal condition in May and June controlled the growth of Larix potaninii. Moisture condition in previous August and current May was the key factor affecting Pinus densata growth. As for Pinus yunnanensis, the drought in current May was the limiting factor influencing its growth. The dynamic relationship between tree growth and climatic factors varied among species, and the results were consistent with response function analysis. A forecast in future forest growth on Haba Snow Mountain was complex, since future climate change had both positive and negative effects on the radial growth of four major conifers.     

Factor analysis in clusterbean (Cyamopsis tetragonoloba (L.) Taub)

Summary The pattern of diversity in forty genotypes of clusterbean (Cyamopsis tetragonoloba (L.) Taub) was analysed using the centroid method of factor analysis based on nine characters. Three factors were found to adequately account for most of the intercorrelations in the four environments. Branches, clusters, pods and seed yield/plant could be grouped as productivity factors; days to flowering, maturity and plant height as growth factors; seeds/pod and gum content as economic factor. Interestingly, the constitution of the factors were the same in all the environments. The loadings on the economic factors were relatively unstable, whereas the loadings on productivity and growth factors were stable. It is concluded that productivity and growth factors play a pivotal role towards diversity in clusterbean. The results of factor analysis provides confirmatory evidence of diversity in clusterbean, which was earlier studied by using generalized distance, and thus proves the adequacy of the centroid method in biological investigations.     

林木生长的多维时间序列分析

利用多维时间序列分析方法,以影响杉木直径生长的五大主导气象要素作控制因子,建立杉木直径生长的ＣＡＲ模型,从而对杉木直径生长提前一年作预测,回验结果表明模型准确率很高,为林木生长预测预报提供了一种新方法．     

中国青年生长发育环境差异的研究

本文应用因子分析方法确定身高、体重、胸围三项指标的权重系数,计算出中国28个城市18岁汉族男女青年生长发育水平的“发育分”。并将发育分与有关自然环境因素进行了相关性研究。发育分与地球纬度、日照时数、气温年较差等具有高度相关性(r=0.6221～0.6715ρ<0.01),与其它气候因素也有相关性。不同水系水质地区的发育分有显著性差异(ρ<0.05—0.01)。由此提示,自然环境因素,是影响人类生长发育的一个不可忽视的因素。     

The Use of Canonical Correlation Analysis in the Investigation of Relationships Between Plant Growth and Environmental Factors

The relationship between environmental factors and growth inImpatiens parviflora was analysed by the method of canonicalcorrelation analysis. The method was able to identify the majorrelationships which had been detected by conventional methodsof analysis. The method was also able to detect relationshipsnot identified by conventional methods. The canonical correlationanalysis also clearly showed that relationships between growthand environment detected at a plant dry weight of 100 mg couldalso be detected at 300 mg despite masking due to ontogeneticdrift and confusion by different patterns of adaptation. Itis concluded that the method of canonical correlation analysisis most useful for the analysis of considerable bodies of datarelating plant growth to environmental factors. Marked effectsof spectral composition on growth and development of both leavesand stems were demonstrated. Different spectral compositioneffects on hypocotyl and internode elongation exist. Impatiens parviflora, growth analysis, canonical correlation analysis, spectral composition, stemelongation     

The genome of Shope fibroma virus, a tumorigenic poxvirus, contains a growth factor gene with sequence similarity to those encoding epidermal growth factor and transforming growth factor alpha.

Degenerate oligonucleotide probes corresponding to a highly conserved region common to epidermal growth factor, transforming growth factor alpha, and vaccinia growth factor were used to identify a novel growth factor gene in the Shope fibroma virus genome. Sequence analysis indicates that the Shope fibroma growth factor is a distinct new member of this family of growth factors.     

玉龙雪山东坡不同海拔长苞冷杉径向生长与气候因子的关系

基于树木年代学方法,利用玉龙雪山东坡长苞冷杉树轮宽度资料,分别建立了3个海拔(低、中、高)长苞冷杉差值年表(RES),并利用响应分析与冗余分析(RDA)研究其径向生长与温度和降水的相关关系,分析影响玉龙雪山长苞冷杉径向生长的主要气候因子.结果表明: 玉龙雪山不同海拔长苞冷杉径向生长受气候变化的影响具有一致性,温度和降水共同作用于径向生长,这种一致性与玉龙雪山地形陡峭以及长苞冷杉的高海拔分布与浅根特性有关.不同海拔长苞冷杉径向生长均与当年7月和上年11月平均温以及当年1月降水量呈显著正相关,而与当年6月降水量呈显著负相关.响应分析与冗余分析的综合应用能够准确揭示环境梯度上树木生长与气候因子的关系.本研究可为该地区历史气候重建以及森林经营管理提供科学依据.     

长白山东坡不同海拔长白落叶松径向生长对气候变化的响应

为了解高山林线附近树木生长对气候变化的敏感性, 选取长白山东坡火山喷发后形成的过渡性植物群落长白落叶松(又称黄花落叶松) (Larix olgensis)林为研究对象, 并建立不同海拔高度长白落叶松的3个年轮宽度年表, 研究不同生境长白落叶松径向生长对气候变化的响应, 并利用冗余分析对不同海拔的年轮指数与气候因子的关系做进一步分析。主要结果如下: (1)高海拔年轮年表的统计特征更显著, 比低海拔径向生长对气候因子的响应更加敏感; (2)高海拔径向生长主要受上年生长季前期和生长季气温的限制, 尤其是上年6月和8月气温的限制作用, 低海拔径向生长主要与降水量有关, 受当年9月降水量和当年8月帕尔默干旱指数(PDSI)的共同影响; (3)林线内树木对气候响应的敏感性强于林线外, 林线外小生境的异质性及干扰事件频发可能掩盖了树木对气候因子的敏感性, 林线下方可能是检验林线处树木生长对气候响应平均状态的最佳位置; (4)不同海拔年轮年表与气候因子的冗余分析与响应函数分析的结果基本一致, 进一步证明了冗余分析可以有效地量化树轮指数与气候因子的关系。该研究为全球变暖背景下长白山东坡长白落叶松林的管理及该区域气候重建提供了基础数据。     

不同海拔温度和降水对新疆阿尔泰山西伯利亚落叶松径向生长的影响

为定量并分离关键气候因子对新疆阿尔泰山不同海拔树木径向生长的影响,通过对高、中和低海拔的西伯利亚落叶松(Larixsibirica)树轮宽度标准年表与气候因子分别进行相关、多元线性回归等统计分析,并进一步计算了线性模型中不同气候因素的绝对和相对贡献率。结果表明,高海拔地区,当年6月温度和上年7月降水分别与径向生长呈显著正相关和负相关,两者共同解释西伯利亚落叶松径向生长变异的33.1%,相对贡献率分别为66.2%和33.8%;中海拔地区,当年6月温度和上年6月降水分别与径向生长呈显著正相关和负相关,两者共同解释径向生长变异的26.8%,相对贡献率分别为40.1%和59.9%;低海拔地区,上年6月温度和7月降水分别与径向生长呈显著负相关和正相关,两者共同解释径向生长变异的29.4%,相对贡献率分别为31.9%和68.1%。这表明限制树木径向生长的主要影响因子随海拔的不同而异,在高海拔地区,温度是主要限制因子;而在低海拔地区,降雨是主要限制因子。     

Regulation of rat proximal tubule epithelial cell growth by fibroblast growth factors, insulin-like growth factor-1 and transforming growth factor-beta, and analysis of fibroblast growth factors in rat kidney.

Growth factors may play an important role in regulating the growth of the proximal tubule epithelium. To determine which growth factors could be involved, we have investigated the mitogenicity of various purified factors in rat kidney proximal tubule epithelial (RPTE) cells cultured in defined medium. Fibroblast growth factors, aFGF (acidic FGF) and bFGF (basic FGF), stimulate DNA synthesis in a dose-dependent manner, with ED50 values of 4.5 and 3.2 ng/ml, respectively; their effects are not additive. With cholera toxin in the medium, both aFGF and bFGF can replace insulin or epidermal growth factor (EGF) to attain the maximum level of cell growth, but they cannot replace cholera toxin. Cholera toxin specifically potentiates the effects of FGFs on DNA synthesis. At high cell density, both insulin and insulin-like growth factor 1 (IGF-1) induce DNA synthesis more effectively than EGF, FGFs and cholera toxin. The high concentration (0.2-1.0 microgram/ml) of insulin required for cell growth can be replaced by a low concentration of IGF-1 (10-20 ng/ml), indicating that insulin probably acts through a low affinity interaction with the IGF-1 receptor. Transforming growth factor-beta 1 (TGF-beta 1) inhibits DNA synthesis induced by individual factors and combinations of factors in a concentration-dependent manner. Northern blot analysis shows that mRNA for TGF-beta 1, IGF-1, and aFGF, but not bFGF are present in rat kidney. Western blot analysis and bioassay data confirmed that the majority of FGF-like protein in rat kidney is aFGF. The data suggest that in addition to EGF, IGFs, and TGF-beta, FGFs may also be important kidney-derived regulators of proximal tubule epithelial cell growth in vivo and in vitro.     

Effects of growth stimulatory factors on mitogenicity and c-myc expression in poorly differentiated and well differentiated human colon carcinoma cells

We demonstrate the differential sensitivity of poorly differentiated and well differentiated human colon carcinoma cells to nutrients alone or to nutrients and polypeptide growth factors under completely serum-free conditions. 3H-Thymidine incorporation into trichloroacetic acid precipitable material and autoradiographic analysis indicated that nutrient replenishment alone was sufficient to initiate DNA synthesis in quiescent poorly differentiated cells, whereas defined polypeptide growth factors produced no additional effect. In contrast, well differentiated cells were mitogenically stimulated to a much greater extent by growth factors (epidermal growth factor + insulin + transferrin), than by nutrient replenishment alone. Expression of the c-myc protooncogene was increased approximately 5-fold after growth factor addition to the well differentiated cells. Maximal expression of c-myc occurred at 4 h post stimulation. In contrast, nutrients resulted in only a slight up-regulation of c-myc (1.8-fold) at approximately 90 min after addition. Addition of nutrients and/or growth factors to the poorly differentiated colon carcinoma cells resulted in an initial decline in c-myc expression (90 min), presumably due to removal of endogenous growth stimulators. Expression of c-myc returned to baseline levels by 24 h after additions. The results indicate that differential sensitivity to polypeptide growth factors is related to differentiation status in this model system and suggest that the insensitivity of poorly differentiated cells to exogenous growth factors may be due to a greater production of autocrine growth stimulators.