Regression Analyses for Evaluating the Influence of Bacillus cereus on Alfalfa Yield Under Variable Disease Intensity     

Kazmar ER  Goodman RM  Grau CR  Johnson DW  Nordheim EV  Undersander DJ  Handelsman J 《Phytopathology》2000,90(6):657-665

ABSTRACT We developed and tested regression methods to exploit the variability in disease inherent in field experiments, and applied the methods to evaluate strains of Bacillus cereus for biocontrol efficacy. Four B. cereus strains were tested for their effect on alfalfa (Medicago sativa) performance in 16 field trials planted during 1993 to 1996 at multiple sites in Wisconsin. To evaluate performance of the strains, we used the ratio of (metalaxyl response)/(untreated control response) as a measure of disease intensity within the experiments. The ratio of (Bacillus response)/(untreated control response) was then regressed as a function of disease intensity. The slope of the resulting line provides a statistical test to compare performance of the Bacillus strain with that of the untreated seed (H(o): slope = 0) and metalaxyl controls (H(o): slope = 1). Under conditions in which disease occurred, forage yield of plots planted with seed treated with B. cereus strain AS4-12 exceeded yield from the untreated control plots (P = 0.002) and was similar to yield of plots planted with metalaxyl-treated seed (P = 0.14). Yield gain associated with AS4-12 and metalaxyl seed treatment averaged 6.1 +/- 2.8% (+/-standard error) and 3.0 +/- 2.8%, respectively. In contrast to the regression approach, means analysis by analysis of variance did not detect differences among treatments. Three other B. cereus strains either did not increase alfalfa yield or increased yield less than did AS4-12. Metalaxyl and three of the Bacillus strains increased seedling emergence, but the improved stands were not predictive of increased forage yield. In six additional studies conducted for one season in 1997, AS4-12 enhanced yield of two cultivars at diverse locations in Wisconsin, but there was an apparent cultivar-location interaction. A strong correlation between response to AS4-12 and metalaxyl treatment suggests that these treatments controlled similar pathogens, most likely the oomycete pathogens Phytophthora medicaginis and Pythium spp.  相似文献   

The changing bio-politics of the organic: Production, regulation, consumption     

David Goodman 《Agriculture and Human Values》2000,17(3):211-213

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转铁蛋白受体上的犬细小病毒壳体结合位点及其亲和力改变对细胞吸收和感染的影响     

Goodman L B  邱文英 《中国畜牧兽医》2010,37(4)

犬细小病毒及其相近的猫泛白细胞减少征病毒与转铁蛋白受体(TfR)1型结合后而感染宿主细胞,但研究显示犬猫TfRs的不同使病毒的宿主范围和组织嗜性也有所不同。通过点突变及增加或减少糖基化信号改变顶端及类蛋白酶区域残基,然后检测这些突变的TfR与壳体的相互作用,发现大多数的置换体对病毒的结合和摄取几乎没有影响,但在受体顶端区域的一些位点突变可以阻止壳体的结合或在不同程度上降低受体的亲和力。顶端区域的病毒结合面内的多糖同样可以控制壳体的结合。犬细小病毒可用含有犬TfRs特异性的糖基化受体从而介导有效的感染,与之相关的猫泛白细胞减少征病毒却不能。另外,添加一个N-糖基化位点到猫转铁蛋白受体顶端区域的病毒结合面会减少或消除结合和感染。最关键的是,猫转铁蛋白受体第221位残基被任何氨基酸替代都会影响结合和感染,这与被替代残基的生化特性有显著联系。亲和力降低的受体介导感染的能力会发生相应改变。对TfRs突变体在细胞内的结合和摄取形式进行测定,结果显示低亲和力TfRs结合更少的壳体,并且它们吸附于细胞表面和伪足的方式有所不同,但转移至核周包涵体的过程是相似的。  相似文献   

Microclimatic differences between mature loblolly-pine silvopasture and open-pasture     

Uma Karki  Mary S. Goodman 《Agroforestry Systems》2015,89(2):319-325

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Cell recognition during neuronal development   总被引：20，自引：0，他引：20  

C S Goodman  M J Bastiani  C Q Doe  S du Lac  S L Helfand  J Y Kuwada  J B Thomas 《Science (New York, N.Y.)》1984,225(4668):1271-1279

Insect embryos, with their relatively simple nervous systems, provide a model system with which to study the cellular and molecular mechanisms underlying cell recognition during neuronal development. Such an approach can take advantage of the accessible cells of the grasshopper embryo and the accessible genes of Drosophila. The growth cones of identified neurons express selective affinities for specific axonal surfaces; such specificities give rise to the stereotyped patterns of selective fasciculation common to both species. These and other results suggest that early in development cell lineage and cell interactions lead to the differential expression of cell recognition molecules on the surfaces of small subsets of embryonic neurons whose axons selectively fasciculate with one another. Monoclonal antibodies reveal surface molecules in the Drosophila embryo whose expression correlates with this prediction. It should now be possible to isolate the genes encoding these potential cell recognition molecules and to test their function through the use of molecular genetic approaches in Drosophila.  相似文献   

Volcanic activity and climatic changes   总被引：1，自引：0，他引：1  

Bryson RA  Goodman BM 《Science (New York, N.Y.)》1980,207(4435):1041-1044

Radiocarbon dates of volcanic activity suggest variations that appear to be related to climatic changes. Historical eruption records also show variations on the scale of years to centuries. These records can be combined with simple climatic models to estimate the impact of various volcanic activity levels. From this analysis it appears that climatic prediction in the range of 2 years to many decades requires broad-scale volcanic activity prediction. Statistical analysis of the volcanic record suggests that some predictability is possible.  相似文献   

Plant cuticular lipid export requires an ABC transporter   总被引：1，自引：0，他引：1  

Pighin JA  Zheng H  Balakshin LJ  Goodman IP  Western TL  Jetter R  Kunst L  Samuels AL 《Science (New York, N.Y.)》2004,306(5696):702-704

A waxy protective cuticle coats all primary aerial plant tissues. Its synthesis requires extensive export of lipids from epidermal cells to the plant surface. Arabidopsis cer5 mutants had reduced stem cuticular wax loads and accumulated sheetlike inclusions in the cytoplasm of wax-secreting cells. These inclusions represented abnormal deposits of cuticular wax and resembled inclusions found in a human disorder caused by a defective peroxisomal adenosine triphosphate binding cassette (ABC) transporter. We found that the CER5 gene encodes an ABC transporter localized in the plasma membrane of epidermal cells and conclude that it is required for wax export to the cuticle.  相似文献   

High-Power Infrared (8-Micrometer Wavelength) Superlattice Lasers     

G Scamarcio  F Capasso  C Sirtori  J Faist  AL Hutchinson  DL Sivco  AY Cho 《Science (New York, N.Y.)》1997,276(5313):773-776

A quantum-cascade long-wavelength infrared laser based on superlattice active regions has been demonstrated. In this source, electrons injected by tunneling emit photons corresponding to the energy gap (minigap) between two superlattice conduction bands (minibands). A distinctive design feature is the high oscillator strength of the optical transition. Pulsed operation at a wavelength of about 8 micrometers with peak powers ranging from approximately 0.80 watt at 80 kelvin to 0.2 watt at 200 kelvin has been demonstrated in a superlattice with 1-nanometer-thick AlInAs barriers and 4.3-nanometer-thick GaInAs quantum wells grown by molecular beam epitaxy. These results demonstrate the potential of strongly coupled superlattices as infrared laser materials for high-power sources in which the wavelength can be tailored by design.  相似文献   

In vivo modulation of cytolytic activity and Thy-1 expression in TCR-gamma delta+ intraepithelial lymphocytes   总被引：21，自引：0，他引：21  

L Lefrancois  T Goodman 《Science (New York, N.Y.)》1989,243(4899):1716-1718

Although the functional aspects of the alpha beta T cell antigen receptor (TCR) found on most peripheral T cells are well described, the function of the gamma delta TCR remains unclear. Murine intraepithelial lymphocytes (IEL) of the small intestine are CD8+, express the gamma delta TCR, and are constitutively lytic. Fresh IEL from germ-free mice had no lytic activity. Moreover, whereas IEL from normal mice are 30 to 50 percent Thy-1+, IEL from germ-free did not express Thy-1. Acclimation of germ-free mice to nonsterile conditions resulted in the generation of Thy-1+ IEL and induction of lytic activity. Thus CD8+ TCR-gamma delta IEL were regulated by externally derived stimuli via a specific functional interaction between IEL and gut-associated antigens.  相似文献   

Infrared Reflection-Absorption Spectroscopy and STM Studies of Model Silica-Supported Copper Catalysts     

Xu X  Vesecky SM  Goodman DW 《Science (New York, N.Y.)》1992,258(5083):788-790

The structure of model silica-supported copper catalysts has been investigated with scanning tunneling microscopy (STM) and infrared reflection-absorption spectroscopy (IRAS). The IRAS studies of CO on the model silica-supported copper catalysts indicate that there are several types of copper clusters with surface structures similar to (111), (110), and other high-index planes of single-crystal copper. The STM studies show several types of copper clusters on silica and reveal images of metal clusters on an amorphous oxide support with atomic resolution.  相似文献