Lumbar muscle electromyographic dynamic topography during flexion-extension

The objective of this study is to introduce dynamic topography of surface electromyography (SEMG) to visualize lumbar muscle myoelectric activity and provides a new view to analyze muscle activity in vivo. A total of 20 healthy male subjects and 15 males LBP were enrolled. An electrode-array was applied to the lumbar region to collect SEMG. The root mean square (RMS) value was calculated for each channel, and then a 160×120 matrix was constructed using a linear cubic spline interpolation of each scan to create a 2-D color topographic image. Along a definite interval of action, a series of RMS topography matrices was concatenated as a function of position and time, to form a dynamic topographical video of lumbar muscle activity. Relative area (RA), relative width (RW), relative height (RH) and Width-to-Height Ratio (W/H) were chosen as the four quantitative parameters in measuring topographic features. Normal RMS dynamic topography was found to have a consistent, symmetric pattern with a high intensity area in the paraspinal area. LBP patients had a different RMS dynamic topography, with an asymmetric, broad, or disorganized distribution. Quantitative SEMG features were found significantly different between normal control and LBP. After physiotherapy rehabilitation, the dynamic topography images of LBP tended towards the normal pattern.There are obvious differences in lumbar muscle coordination between healthy subjects and LBP patients. The dynamic topography allows the continuous visualization of the distribution of surface EMG signals and the coordination of muscular contractions.     

基于卫星追踪探讨黄河流域自然保护区对3种水鸟栖息地的保护现状

自然保护区是生物多样性保护的重要形式, 对于迁徙水鸟而言, 它的规划尤为重要。本研究于2016-2018年间在中国、蒙古国和俄罗斯捕捉6只斑头雁(Anser indicus)、5只白琵鹭(Platalea leucorodia)和10只东方白鹳(Ciconia boyciana)进行卫星追踪, 探讨了黄河流域自然保护区对它们栖息地的保护现状。基于4年累积获取的844,592条高频数据, 分析了这21只水鸟在黄河流域活动的时间和利用的土地类型, 并使用核密度法拟合了3种鸟类的家域。结果表明: 3种鸟类均利用黄河流域湿地作为迁徙途中的停歇地, 其中一部分白琵鹭幼鸟利用黄河流域湿地作为度夏地, 一部分东方白鹳利用黄河三角洲湿地作为越冬地; 3种水鸟在黄河流域内的土地利用情况存在差异, 斑头雁对草地(49.0%)、裸地(26.2%)与水体(22.5%)的利用率较高, 白琵鹭对农田(42.1%)、草地(19.8%)和湿地(19.6%)的利用率较高, 东方白鹳对湿地(49.8%)、农田(34.5%)和水体(4.6%)的利用率较高; 斑头雁核心的50%家域被现有保护区完全覆盖, 而白琵鹭和东方白鹳核心的50%家域被现有保护区的覆盖度分别为1.6%和0, 表明后2种水鸟的栖息地极大可能存在保护空缺; 同时对覆盖范围内土地类型自身占比进行分析, 发现3种鸟类对于裸地、草地和农田的利用偏向于被动选择, 而对于湿地和水体的利用表现为主动选择。基于卫星追踪获得的高频数据可以准确反映3种水鸟在黄河流域的停歇情况、土地利用情况及潜在栖息位点。在黄河流域自然保护区的进一步规划中, 应关注白琵鹭和东方白鹳适宜生境的保护状况, 并建立覆盖全面的保护区。     

Cytokinins in pathogenesis and disease resistance of Pyrenophora teres-barley and Dreschslera maydis-maize interactions during early stages of infection

Infection of Hordeum vulgare L. by Pyrenophora teresand of Zea mays by Dreschslera maydis were characterized by green island formation, higher cytokinin levels and accumulation of metabolites in the infected areas. Higher cytokinin concentrations of the order 6-Y,Y-dimethylallylaminopurine > zeatinriboside > zeatin >dihydrozeatinriboside were detected at infection sites of susceptible hosts. By virtue of these cytokinins, infection sites may be acting as metabolic sinks helping proliferation of the pathogen. Existence of translocatory sinks at infection zones was confirmed from autoradiographic studies,where, accumulation of labeled metabolites was prominent at infection sites of susceptible hosts. Upon infection the lower cytokinin levels of resistant hosts decreased further with progress of infection. In the infected resistant hosts the concentrations of zeatin/zeatinriboside were the maximum among the four identified cytokinins. The pathogen is also capable of secreting cytokinins as evident from quantification of cytokinins in culture filtrate extracts using HPLC. Since detached leaves were used in the experiments the increase/decrease of various cytokinin levels may be attributed to pathogen influence. The increase in cytokinin levels in the susceptible host may be aiding the growth of the pathogen on one hand, while the decrease in the infected resistant host may signal the host to activate defenses against a potential pathogen at the early stage of infection.This revised version was published online in October 2005 with corrections to the Cover Date.     

Asymmetric synthesis of the stereoisomers of 11,12,15(S)-trihydroxyeicosa-5(Z),8(Z),13(E)-trienoic acid, a potent endothelium-derived vasodilator

The four stereoisomers of the endothelial-derived vasorelaxant 11,12,15(S)-trihydroxyeicosatrienoic acid [1, 11,12,15(S)-THETA] were prepared by a triply convergent, asymmetric route that exploited the stereospecific, copper mediated cross-coupling of alpha,beta-dialkoxystannanes with organic electrophiles and the utility of dialkylthionocarbamates as orthogonal alcohol protective groups. Only 11(R),12(S),15(S)-THETA was comparable to natural material by HPLC, GC/MS, and in vitro bioassay.     

A comparative study of the effect of morphactin and Niagara on the leaf epidermis

Treatment of two-week-oldBrassica campestris andTrigonella foenum-graecum plants with morphactin andVicia faba, Antirrhinum orontium, andPapaver somniferum with Niagara, induced marked variations in the orientation and ontogeny of stomata and the epiderma cells. Morphactin—chlorflurenol at 12.5, 62.5, 125, 250, and 500 ppm, caused marked damage of the shoot apices and changes in the epidermal tissue, such as divisions of the guard cells, reduction in the size of the stomata, and epidermal cells. Niagara—ethyl-hydrogen-1-propylphosphonate at 100, 500, 1 000 5 000, and 10 000 ppm caused thickenings of the epidermal cell walls and differentiation of new meristemoids from the epidermal cells, contiguous stomata, and incomplete development of the guard cells.     

iRFP is a sensitive marker for cell number and tumor growth in high-throughput systems

GFP and luciferase are used extensively as markers both in vitro and in vivo although both have limitations. The utility of GFP fluorescence is restricted by high background signal and poor tissue penetrance. Luciferase throughput is limited in vitro by the requirement for cell lysis, while in vivo, luciferase readout is complicated by the need for substrate injection and the dependence on endogenous ATP. Here we show that near-infrared fluorescent protein in combination with widely available near-infrared scanners overcomes these obstacles and allows for the accurate determination of cell number in vitro and tumor growth in vivo in a high-throughput manner and at negligible per-well costs. This system represents a significant advance in tracking cell proliferation in tissue culture as well as in animals, with widespread applications in cell biology.     

Inhibition of telomerase by BIBR 1532 and related analogues

BIBR 1532 has been reported to be a potent, small molecule inhibitor of human telomerase, suggesting it as a lead for the development of anti-telomerase therapy. We confirm the ability of BIBR 1532 to inhibit telomerase and report the discovery of an equally potent analogue. Importantly, IC(50) values in cell extract are considerably higher than those previously reported using assays for purified enzyme, indicating that substantial improvement may be necessary.