Development of Model Systems to Screen Elms Resistant to Dutch Elm Disease

1993 ◽  
pp. 181-187
Author(s):  
Subhash C. Domir ◽  
Lawrence R. Schreiber ◽  
Paula M. Pijut
Author(s):  
H.M. Mazzone ◽  
G. Wray ◽  
R. Zerillo

The fungal pathogen of the Dutch elm disease (DED), Ceratocystis ulmi (Buisman) C. Moreau, has eluded effective control since its introduction in the United States more than sixty years ago. Our studies on DED include establishing biological control agents against C. ulmi. In this report we describe the inhibitory action of the antibiotic polymyxin B on the causal agent of DED.In screening a number of antibiotics against C. ulmi, we observed that filter paper discs containing 300 units (U) of polymyxin B (Difco Laboratories) per disc, produced zones of inhibition to the fungus grown on potato dextrose agar or Sabouraud agar plates (100mm x 15mm), Fig. 1a. Total inhibition of fungal growth on a plate occurred when agar overlays containing fungus and antibiotic (polymyxin B sulfate, ICN Pharmaceuticals, Inc.) were poured on the underlying agar growth medium. The agar overlays consisted of the following: 4.5 ml of 0.7% agar, 0.5 ml of fungus (control plate); 4.0 ml of 0.7% agar, 0.5 ml of fungus, 0.5 ml of polymyxin B sulfate (77,700 U). Fig. 1, b and c, compares a control plate and polymyxin plate after seven days.


Author(s):  
B. L. Redmond ◽  
Christopher F. Bob

The American Elm (Ulmus americana L.) has been plagued by Dutch Elm Disease (DED), a lethal disease caused by the fungus Ceratocystis ulmi (Buisman) c. Moreau. Since its initial appearance in North America around 1930, DED has wrought inexorable devastation on the American elm population, triggering both environmental and economic losses. In response to the havoc caused by the disease, many attempts have been made to hybridize U. americana with a few ornamentally less desirable, though highly DED resistant, Asian species (mainly the Siberian elm, Ulmus pumila L., and the Chinese elm Ulmus parvifolia Jacq.). The goal is to develop, through breeding efforts, hybrid progeny that display the ornamentally desirable characteristics of U. americana with the disease resistance of the Asian species. Unfortunately, however, all attempts to hybridize U. americana have been prevented by incompatibility. Only through a firm understanding of both compatibility and incompatibility will it be possible to circumvent the incompatibility and hence achieve hybridization.


Author(s):  
K. Brasch ◽  
J. Williams ◽  
D. Gallo ◽  
T. Lee ◽  
R. L. Ochs

Though first described in 1903 by Ramon-y-Cajal as silver-staining “accessory bodies” to nucleoli, nuclear bodies were subsequently rediscovered by electron microscopy about 30 years ago. Nuclear bodies are ubiquitous, but seem most abundant in hyperactive and malignant cells. The best studied type of nuclear body is the coiled body (CB), so termed due to characteristic morphology and content of a unique protein, p80-coilin (Fig.1). While no specific functions have as yet been assigned to CBs, they contain spliceosome snRNAs and proteins, and also the nucleolar protein fibrillarin. In addition, there is mounting evidence that CBs arise from or are generated near the nucleolus and then migrate into the nucleoplasm. This suggests that as yet undefined links may exist, between nucleolar pre-rRNA processing events and the spliceosome-associated Sm proteins in CBs.We are examining CB and nucleolar changes in three diverse model systems: (1) estrogen stimulated chick liver, (2) normal and neoplastic cells, and (3) polyploid mouse liver.


Author(s):  
Yih-Tai Chen ◽  
Ursula Euteneuer ◽  
Ken B. Johnson ◽  
Michael P. Koonce ◽  
Manfred Schliwa

The application of video techniques to light microscopy and the development of motility assays in reactivated or reconstituted model systems rapidly advanced our understanding of the mechanism of organelle transport and microtubule dynamics in living cells. Two microtubule-based motors have been identified that are good candidates for motors that drive organelle transport: kinesin, a plus end-directed motor, and cytoplasmic dynein, which is minus end-directed. However, the evidence that they do in fact function as organelle motors is still indirect.We are studying microtubule-dependent transport and dynamics in the giant amoeba, Reticulomyxa. This cell extends filamentous strands backed by an extensive array of microtubules along which organelles move bidirectionally at up to 20 μm/sec (Fig. 1). Following removal of the plasma membrane with a mild detergent, organelle transport can be reactivated by the addition of ATP (1). The physiological, pharmacological and biochemical characteristics show the motor to be a cytoplasmic form of dynein (2).


Author(s):  
Ian M. Anderson ◽  
Arnulf Muan ◽  
C. Barry Carter

Oxide mixtures which feature a coexistence of phases with the wüstite and spinel structures are considered model systems for the study of solid-state reaction kinetics, phase boundaries, and thin-film growth, and such systems are especially suited to TEM studies. (In this paper, the terms “wüstite” and “spinel” will refer to phases of those structure types.) The study of wüstite-spinel coexistence has been limited mostly to systems near their equilibrium condition, where the assumptions of local thermodynamic equilibrium are valid. The cation-excess spinels of the type Ni2(1+x)Ti1-xO4, which reportedly exist only above 1375°C4, provide an excellent system for the study of wüstite-spinel coexistence under highly nonequilibrium conditions. The nature of these compounds has been debated in the literature. X-ray and neutron powder diffraction patterns have been used to advocate the existence of a single-phase, non- stoichiometric spinel. TEM studies of the microstructure have been used to suggest equilibrium coexistence of a stoichiometric spinel, Ni2TiO4, and a wüstite phase; this latter study has shown a coexistence of wüstite and spinel phases in specimens thought to have been composed of a single, non- stoichiometric spinel phase. The microstructure and nature of this phase coexistence is the focus of this study. Specimens were prepared by ball-milling a mixture of NiO and TiO2 powders with 10 wt.% TiO2. The mixture was fired in air at 1483°C for 5 days, and then quenched to room temperature. The aggregate thus produced was highly porous, and needed to be infiltrated prior to TEM sample preparation, which was performed using the standard techniques of lapping, dimpling, and ion milling.


2000 ◽  
Vol 12 (3) ◽  
pp. 45-53
Author(s):  
Andrew Beaulieu ◽  
Jacques Boisseau ◽  
Carl Cerniglia ◽  
Denis Corpet ◽  
A. Haydée Fernández ◽  
...  

1976 ◽  
Vol 21 (8) ◽  
pp. 600-601
Author(s):  
RICHARD F. THOMPSON

2010 ◽  
Author(s):  
Ellen Schelly Hill ◽  
Jaqui Blatt ◽  
Jill Comins ◽  
Cynthia Jones ◽  
Anne Margrethe Melsom

2020 ◽  
Author(s):  
H Gaitantzi ◽  
C Cai ◽  
S Asawa ◽  
K Böttcher ◽  
M Ebert ◽  
...  

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