Cryptic phenology in plants: Case studies,implications, and recommendations

Plant phenology—the timing of cyclic or recurrent biological events in plants—offers insight into the ecology, evolution, and seasonality of plant‐mediated ecosystem processes. Traditionally studied phenologies are readily apparent, such as flowering events, germination timing, and season‐initiating budbreak. However, a broad range of phenologies that are fundamental to the ecology and evolution of plants, and to global biogeochemical cycles and climate change predictions, have been neglected because they are “cryptic”—that is, hidden from view (e.g., root production) or difficult to distinguish and interpret based on common measurements at typical scales of examination (e.g., leaf turnover in evergreen forests). We illustrate how capturing cryptic phenology can advance scientific understanding with two case studies: wood phenology in a deciduous forest of the northeastern USA and leaf phenology in tropical evergreen forests of Amazonia. Drawing on these case studies and other literature, we argue that conceptualizing and characterizing cryptic plant phenology is needed for understanding and accurate prediction at many scales from organisms to ecosystems. We recommend avenues of empirical and modeling research to accelerate discovery of cryptic phenological patterns, to understand their causes and consequences, and to represent these processes in terrestrial biosphere models.     

九节龙皂苷诱导胶质瘤SHG-44细胞凋亡的实验观察

目的：探讨九节龙皂苷对胶质瘤SHG-44细胞潜在的治疗作用及其机制。方法：用四基偶唑蓝（MTT）法检测5、7．5、10、12．5、15、20、40、80mg／L九节龙皂苷作用6、12、24、72h对人胶质瘤SHG-44细胞活性的影响和细胞流式术检测SGH-44细胞调亡情况;Hoeehst33258荧光染色法观察细胞形态的变化;琼脂糖凝胶电泳检测SHG-44细胞DNA的完整性。结果：九节龙皂苷明显抑制SHG-44细胞生长活性呈浓度-时间依赖性,并诱导细胞发生明显的凋亡,细胞核发生浓聚边集,DNA呈凋亡特异性“梯状”分布。结论：九节龙皂苷明显抑制SHG-44细胞的生长活性,能引起胶质瘤细胞大量凋亡,具有显著的抗肿瘤作用。     

Chromosomal localization of the loci responsible for dystrophic cardiac calcinosis in DBA/2 mice.

Dystrophic cardiac calcinosis (DCC) occurs in certain inbred strains of mice, including DBA/2 and C3H/He, and is generally found as an incidental lesion in adult animals at necropsy. Preliminary genetic studies into the cause of DCC have been performed in DBA/2 mice and suggest that DCC is inherited as an autosomal recessive trait involving three or four unlinked genes. To investigate the genetics of DCC further, we produced myocardial cell death by freeze-thaw injury to induce DCC. Experiments were conducted with three F1 hybrids made using three inbred strains of mice (DBA/2J and C3H/HeJ, DCC-susceptible strains; C57BL/6J, DCC-resistant strain) to compare the genetic factors in the development of DCC. We found that DBA/2 and C3H/He mice share the same gene pattern(s) that is responsible for DCC. We determined by backcross linkage analysis in DBA/2 and C57BL/6 mice that at least one recessive locus is responsible for DCC. A haplotype analysis of the backcross data demonstrated that the recessive locus, designated dyscalc1, is located on Chromosome 7, 20.5 cM distal to the centromere. The likely candidate genes for dyscalc1 are discussed. Further understanding of the structure and function of these mutant genes will be beneficial in explaining the molecular pathogenesis of DCC.     

PTSD促进大鼠中缝背核细胞色素c表达

目的研究创伤后应激障碍(PTSD)大鼠中缝背核神经元细胞色素C(Cyt-c)的表达变化。方法应用无连续单一刺激(SPS)方法建立PTSD大鼠模型,随机分为SPS刺激后1d、4d、7d和对照组,应用酶组织化学法和RT-PCR方法观察中缝背核神经元Cyt-c的表达变化。结果光镜酶细胞化学法和RT-PCR法显示中缝背核神经元Cyt-c染色阳性细胞于SPS刺激后1d明显高于对照组,4d逐渐增高,并于7d达到高峰。电镜下显示Cyt-c阳性反应产物主要分布在中缝背核神经元线粒体膜,SPS刺激后可见Cyt-c释放到胞浆中。结论 SPS刺激引起Cyt-c在PTSD大鼠中缝背核神经元呈过表达。     

杂交水稻及其“三系”线粒体DNA的AP—PCR指纹图谱

为了研究水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）细胞质雄性不育（ＣＭＳ）与线粒体基因组的关系,应用ＡＰ－ＰＣＲ 分析,用７ 个任意单引物对６ 种水稻品系线粒体ＤＮＡ 进行了扩增。水稻线粒体ＤＮＡ 的ＡＰ－ＰＣＲ 产物可分为三种类型：（１）所有供试品系均能扩增的片段,它们代表了线粒体ＤＮＡ 在进化上的保守性序列。有４ 个引物检测到这类片段。（２）２ 个以上水稻品系共同出现而在全部供试材料间存在差异的扩增片段,这类片段是检测水稻线粒体ＤＮＡ多态性的主要来源。（３）一种细胞质类型所特有的扩增片段,从引物Ｒ２ 和Ｖ５ 的扩增产物中发现了这类片段,它们可能与ＣＭＳ有关联。另外,ＷＡ型不育系珍汕９７Ａ 与其杂种之间在６ 个引物的扩增图谱上均存在不同程度的差异,说明两者的线粒体ＤＮＡ序列结构可能存在某种差别     

Comparative analysis of vascular endothelial cell activation by TNF-α and LPS in humans and baboons

As an Old World nonhuman primate, baboons have been extensively used for research on dyslipidemia and atherogenesis. With increasing knowledge about the endothelium's role in the initiation and progression of atherosclerosis, the value of the baboon model can be increased by developing it for research on the role of dysfunctional endothelium in atherogenesis. Toward that goal, we have established and validated methods of isolating and culturing baboon femoral artery endothelial cells (BFAECs) and compared baboon endothelial cellular characteristics with those of humans. Our results indicated that baboon and human endothelial cells share similar growth and culture behaviors. As was the case for human endothelial cells, BFAECs responded to tumor necrosis factor (TNF)-α stimulation with increased expression of adhesion molecules (maximum increase for intracellular adhesion molecule (ICAM): 1.76±0.26-fold; vascular cell adhesion molecule (VCAM): 1.65±0.25-fold; E-selectin: 2.86±0.57-fold). However, BFAECs were hyporesponsive to lipopolysaccharide (LPS) (range, 0.25–20 μg/mL) in adhesion molecule expression, whereas 1 μg/mL LPS induced 2.14- to 3.71-fold increases in human endothelial cells. The differential responses to LPS were not related to TLR-2 and toll-like receptor (TLR)-4 expression on the cell surface. And baboon microvascular endothelial cells had similar features as BFAECs. We observed constitutive expression of interleukin (IL)-6, IL-8, granulocyte macrophage colony-stimulating factor (GM-CSF), and monocyte chemoattractant protein (MCP)-1 in both human and baboon endothelial cells, and these cytokines were further induced by TNF-α and LPS. We also demonstrated that the responses to TNF-α or LPS varied among baboons maintained under the same dietary and environmental conditions, suggesting that response may be controlled by genetic factors.     

Application of fuzzy reasoning to control of glucose and ethanol concentrations in baker's yeast culture

Fuzzy reasoning was applied to control both ethanol and glucose concentrations in fed-batch cultures of baker's yeast. This fuzzy controller consisted of three membership functions (concentrations of dissolved oxygen (DO), ethanol and glucose) and 18 production rules. Fuzzy inference was carried out by IF {A is a and B is b,...#x007D;, THEN {C is c} from the on-line measured concentrations of DO, ethanol and glucose. When medium concentrations of ethanol and glucose in fed-batch culture of baker's yeast were set at 2 g/l and 0.2 g/l, both ethanol and glucose concentrations were controlled at 2.67±0.35 g/l and 0.27±0.25 g/l, respectively, ethanol production was reduced from 26 g/l to 34 g/l, cell yield increased from 0.38 to 0.53 g dry cell/g consumed glucose and ethanol yield decreased from 0.50 to 0.14 g ethanol/g consumed glucose, respectively, as compared with those of the glucose only control at 0.2 g/l.     

Nitrogen economy of alpine plants on the north Tibetan Plateau: Nitrogen conservation by resorption rather than open sources through biological symbiotic fixation

Nitrogen (N) is one of the most important factors limiting plant productivity, and N fixation by legume species is an important source of N input into ecosystems. Meanwhile, N resorption from senescent plant tissues conserves nutrients taken up in the current season, which may alleviate ecosystem N limitation. N fixation was assessed by the ¹⁵N dilution technique in four types of alpine grasslands along the precipitation and soil nutrient gradients. The N resorption efficiency (NRE) was also measured in these alpine grasslands. The aboveground biomass in the alpine meadow was 4–6 times higher than in the alpine meadow steppe, alpine steppe, and alpine desert steppe. However, the proportion of legume species to community biomass in the alpine steppe and the alpine desert steppe was significantly higher than the proportion in the alpine meadow. N fixation by the legume plants in the alpine meadow was 0.236 g N/m², which was significantly higher than N fixation in other alpine grasslands (0.041 to 0.089 g N/m²). The NRE in the alpine meadows was lower than in the other three alpine grasslands. Both the aboveground biomass and N fixation of the legume plants showed decreasing trends with the decline of precipitation and soil N gradients from east to west, while the NRE of alpine plants showed increasing trends along the gradients, which indicates that alpine plants enhance the NRE to adapt to the increasing droughts and nutrient‐poor environments. The opposite trends of N fixation and NRE along the precipitation and soil nutrient gradients indicate that alpine plants adapt to precipitation and soil nutrient limitation by promoting NRE (conservative nutrient use by alpine plants) rather than biological N fixation (open sources by legume plants) on the north Tibetan Plateau.     

我国新分离虫媒病毒的初步鉴定

1990－1994年,从新疆地区的蚊、蜱和病人血清分离了多株病毒,为了明确这些病毒的分类地位,对其中的20株病毒进行了组织培养细胞感染实验和血清学检验,对部分毒株做了动物接种实验和理化性质鉴定。结果显示：20株病毒均可使BHK－21细胞病变（1－3天）,主要表现为细胞圆宿、聚集,融合,破碎,脱落等;致Vero细胞病变为2－4天;15株病毒致C6／36细胞病变（2－4天）,5株病毒对C6／36细胞连续观察7天未见细胞病变。11株病毒对乳鼠2－4天致死,对成年鼠2－5天致死。选取6株病毒进行理化性质鉴定,4株病毒（90260、91002、91004和91028）对5－氟脱氧尿苷耐受,对乙醚和酸敏感,提示为有膜RNA病毒;一株病毒（90265）对5－氟脱氧尿苷、乙醚和酸均敏感,提示为有膜DNA病毒;另一株病毒（9059）对5－氟脱氧尿苷耐受,对乙醚和酸也耐受,提示可能为无膜RNA肠道病毒。20株病毒中,17株病毒与甲病毒、乙型脑炎病毒和布尼亚病毒的特异性免疫腹水不反应,提示这些病毒中可能不存在甲病毒、黄病毒和布尼亚病毒;3株病毒（90260、91002和91004）只与甲病毒的特异性免疫腹水反应,与乙型脑炎病毒和布尼亚病毒的不反应,提示这三株病毒为甲病毒。     

NPM1突变基因表达抑制K562白血病细胞体外增殖和侵袭

核仁磷酸蛋白(nucleophosmin,NPM1)突变是近年发现的在急性髓系白血病中发挥重要作用的基因改变,为探讨NPM1突变对K562白血病细胞体外增殖和侵袭能力的影响,将载体pEGFPC1-NPM1-mA转染K562细胞系,构建稳定表达NPM1突变蛋白的白血病细胞株(K562-mA)。利用细胞生长曲线观察细胞体外增殖能力;流式细胞仪检测细胞周期进程改变;细胞粘附、Transwell实验分别用以观察细胞体外粘附、迁移及侵袭能力。结果发现,NPM1突变转染后K562细胞体外增殖能力明显减弱;同时G1期细胞比例明显增高,S期细胞比例显著减低。与未处理组和空载体转染组细胞相比,K562-mA细胞体外迁移能力有所增加,但细胞粘附及侵袭能力却明显减弱。提示NPM1突变基因的表达能够抑制白血病细胞体外增殖和侵袭能力,为进一步深入探讨NPM1突变在白血病发生发展中的调控机制奠定了良好的基础。