Interactions of the bean rust and cowpea rust fungi with species of the Phaseolus–Vigna plant complex. II. Histological responses to infection in heat-treated and untreated leaves

1989 ◽  
Vol 67 (1) ◽  
pp. 58-72 ◽  
Author(s):  
Janice F. Elmhirst ◽  
Michèle C. Heath
Keyword(s):  
Heat Treatment ◽  
Related Species ◽  
High Frequency ◽  
Colony Formation ◽  
Specific Resistance ◽  
Rust Fungus ◽  
Rust Fungi ◽  
Taxonomic Group ◽  
Bean Rust ◽  
Heat Treated

A comparison of the histological responses of species within the Phaseolus–Vigna plant complex to single isolates of the bean and cowpea rust fungi revealed that no particular response was restricted to any plant taxonomic group, although species differed in the proportion of infection sites at which a particular response was exhibited. Related species did not always show similar frequencies of responses and sometimes there were differences between different genotypes within a nonhost species. In host and nonhost species, preinoculation heat treatment commonly inhibited prehaustorial defenses and delayed the death of the invaded cell. Growing fungal colonies subsequently developed in many species, even those considered nonhosts, particularly if they exhibited a high frequency of prehaustorial defenses in untreated leaves. It is argued that a lack of heat-induced colony formation is a sign of parasite-specific resistance, which most likely evolved only in originally susceptible plants. Consequently, the data suggest that the bean rust fungus has had a long association with American species of the complex and that extant nonhost species may have evolved from susceptible ancestors. In contrast, the cowpea rust fungus appears to have had little evolutionary contact with these American species and may not be as closely related to the bean rust fungus as originally thought.

Host species specificity of the goldenrod rust fungus and the existence of rust resistance within some goldenrod species

1992 ◽  
Vol 70 (12) ◽  
pp. 2461-2466 ◽  
Author(s):  
Michèle C. Heath
Keyword(s):  
British Columbia ◽  
Rust Resistance ◽  
Selective Pressure ◽  
Specific Resistance ◽  
Rust Fungus ◽  
Single Gene ◽  
Rust Fungi ◽  
Nonhost Resistance ◽  
Low Levels ◽  
Coleosporium Asterum

Five out of six species of goldenrod at a study site in Ontario had rust pustules in the field and also developed pustules after laboratory inoculation with urediospores of a single-pustule isolate of the rust fungus (Coleosporium asterum) obtained from Solidago canadensis. This isolate also successfully infected seedlings of S. canadensis and an additional goldenrod species from British Columbia. Light microscopy revealed low levels of spore germination and high levels of failed infection attempts even on susceptible plants; in S. canadensis, infection commonly failed before the formation of the first haustorium, a phenomenon typical of nonhost resistance and indicative of a degree of nonspecific incompatibility between fungus and host. Only 2 out of over 200 S. canadensis seedlings from Ontario or British Columbia lacked pustules after repeated inoculations compared with 7 out of 36 for Solidago rugosa seedlings from the study site. Microscopically, infection sites in most of these resistant plants resembled those in crop plants with parasite-specific, single-gene resistance. The data raise the possibility that the fungus has exerted a stronger selective pressure for parasite-specific resistance on S. rugosa than on S. canadensis. Key words: Coleosporium asterum, goldenrod, rust fungi, Solidago, specificity.

scholarly journals Modeling the influence of thermal modification on the electrical conductivity of wood

Holzforschung ◽  
2014 ◽  
Vol 68 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Christian Brischke ◽  
Kathrin A. Sachse ◽  
Christian R. Welzbacher
Keyword(s):  
Experimental Data ◽  
Heat Treatment ◽  
Electrical Conductivity ◽  
Moisture Content ◽  
Electrical Resistance ◽  
Specific Resistance ◽  
Thermal Modification ◽  
Heat Treated ◽  
Wood Temperature ◽  
Color Data

Abstract A model has been developed aiming at the description of the effect of thermal modification on the electrical conductivity of wood. The intention was to calculate the moisture content (MC) of thermally modified timber (TMT) through the parameters electrical resistance R, wood temperature T, and CIE L*a*b* color data, which are known to correlate well with the intensity of a heat treatment. Samples of Norway spruce (Picea abies Karst.) and beech (Fagus sylvatica L.) samples were thermally modified in laboratory scale at 11 different heat treatment intensities and the resistance characteristics of the samples were determined. Within the hygroscopic range, a linear relationship between the resistance characteristics and the mass loss (ML) through the heat treatment was established. Based on this, a model was developed to calculate MC from R, T, and ML. To validate this model, color values of 15 different TMTs from industrial production were determined for estimation of their ML and fed into the model. MC of the 15 arbitrarily heat-treated TMTs was calculated with an accuracy of ±3.5% within the hygroscopic range. The material-specific resistance characteristics based on experimental data led to an accuracy of ±2.5%.

Study of the overtones and combination bands in the Raman spectra of polyparaphenylene-based carbons

1999 ◽  
Vol 14 (8) ◽  
pp. 3447-3454 ◽  
Author(s):  
A. Marucci ◽  
M. A. Pimenta ◽  
S. D. M. Brown ◽  
M. J. Matthews ◽  
M. S. Dresselhaus ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Frequency ◽  
Laser Excitation ◽  
Treatment Temperature ◽  
Visible Range ◽  
Excitation Energies ◽  
First Order ◽  
Heat Treated ◽  
Disordered Carbon ◽  
Combination Bands

A detailed study of the second-order Raman spectrum of the polymer polyparaphenylene (PPP) prepared according to the Kovacic method and heat treated at temperatures THT between 650 and 750 °C is presented. The Raman experiments have been performed with five different laser excitation energies in the visible range between 1.92 and 3.05 eV. Several Raman bands in the region between 2400 and 3400 cm−1 have been detected and assigned to the overtones and combination bands of the two conformations of the PPP polymer (benzenoid and quinoid) that co-exist in our samples. Due to the carbonization process, these bands broaden and decrease in intensity with increasing heat treatment temperature, as is also observed for the corresponding first-order Raman features. The complete absence of these high-frequency Raman bands for PPP with heat treatment temperatures in excess of 750 °C indicates complete transformation of the polymer into a disordered carbon material.

An evalution of the nitrous acid – 3-methyl-2-benzothiazolinone hydrazone hydrochloride – ferric chloride assay for chitin in rust fungi and rust-infected tissue

1982 ◽  
Vol 60 (12) ◽  
pp. 2575-2580 ◽  
Author(s):  
Susan G. W. Kaminskyj ◽  
Michèle C. Heath
Keyword(s):  
Ferric Chloride ◽  
Nitrous Acid ◽  
Rust Fungus ◽  
Infected Plant ◽  
French Bean ◽  
Rust Fungi ◽  
Bean Rust ◽  
Reactive Component ◽  
Comparison Of The Results ◽  
Fungus Growth

The growth of the bean rust and cowpea rust fungi was examined in cultivars of French bean and cowpea using light microscopy and the nitrous acid – 3-methyl-2-benzothiazolinone hydrazone hydrochloride – ferric chloride assay for chitin. Comparison of the results indicated that the chitin assay did not detect changes in vegetative growth but only detected substances present in mature and developing urediospores. Examination of urediospores indicated that the reactive component(s) was hexosamine, probably glucosamine, but not chitin. The presence of strongly reactive substances in the urediospores, and the apparent low level of chitin in vegetative mycelium compared with that in the mycelium of the commercial mushroom, suggest that this chitin assay is of little value in estimating rust fungus growth in infected plant tissue.

Growth from Spores of NonproteolyticClostridium botulinum in Heat-Treated Vegetable Juice

1999 ◽  
Vol 65 (5) ◽  
pp. 2136-2142 ◽  
Author(s):  
Sandra C. Stringer ◽  
Nuzrul Haque ◽  
Michael W. Peck
Keyword(s):  
Heat Treatment ◽  
Colony Formation ◽  
Clostridium Botulinum ◽  
Culture Media ◽  
Water Bath ◽  
Vegetable Juice ◽  
Heat Treated ◽  
First Time

ABSTRACT Unheated spores of nonproteolytic Clostridium botulinumwere able to lead to growth in sterile deoxygenated turnip, spring green, helda bean, broccoli, or potato juice, although the probability of growth was low and the time to growth was longer than the time to growth in culture media. With all five vegetable juices tested, the probability of growth increased when spores were inoculated into the juice and then heated for 2 min in a water bath at 80°C. The probability of growth was greater in bean or broccoli juice than in culture media following 10 min of heat treatment in these media. Growth was prevented by heat treatment of spores in vegetable juices or culture media at 80°C for 100 min. We show for the first time that adding heat-treated vegetable juice to culture media can increase the number of heat-damaged spores of C. botulinum that can lead to colony formation.

Effects of Postweld Heat-Treatment on Girth Weld Tensile Property and Microstructure of High-Frequency Electric Resistance Welded Pipe for API X80 Grade Casing Pipe

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Sota Goto ◽  
Shunsuke Toyoda ◽  
Shinsuke Ide ◽  
Yukihiko Okazaki ◽  
Kota Nakashima
Keyword(s):  
Heat Treatment ◽  
Tensile Properties ◽  
Base Metal ◽  
High Frequency ◽  
Postweld Heat Treatment ◽  
Small Scale ◽  
Electric Resistance ◽  
Heat Treated ◽  
Welded Pipe ◽  
Postweld Heat

The girth weld tensile properties of API X80 grade high-frequency electric resistance welded (HFW) steel pipe for surface casing with the chemical composition of 0.05C–1.6Mn–0.06Nb (mass %) and the diameter of 558.8 mm and wall thickness of 25.4 mm were investigated by simulated postweld heat-treatment (PWHT). The tensile specimens taken from girth butt welded pipe were heat-treated under the conditions of 625 °C × 2 h and 675 °C × 2 h in an air furnace in order to simulate PWHT of casing products. The result of the girth weld tensile test of the heat-treated specimens showed that yield strength and tensile strength decreased very little and these properties sufficiently satisfied the API X80 specification. The change in strength due to heat treatment was discussed based on microscopic observation of the submicrostructures of the base metal by the electron back-scattered diffraction (EBSD) technique, transmission electron microscopy, X-ray diffraction (XRD), and the extraction residue precipitate classification method. The authors concluded that the fine NbC with a diameter of 12–18 nm, which precipitated during the heat treatment, prevented the decrease of strength due to the slight grain growth and dislocation recovery associated with PWHT. Additionally, the effect of PWHT conditions was evaluated by using small-scale laboratory specimens obtained from the base metal. Tensile properties were summarized as a function of the tempering parameter. As a result, strength remained almost constant at the tempering parameter equivalent to the PWHT conditions of 625 °C × 16 h.

Comparative analysis of proteins of Uromyces phaseoli var. typica, U. phaseoli var. vignae, and U. viciae-fabae: polypeptide mapping by two-dimensional electrophoresis

1985 ◽  
Vol 63 (12) ◽  
pp. 2144-2149 ◽  
Author(s):  
W. K. Kim ◽  
Michèle C. Heath ◽  
R. Rohringer
Keyword(s):  
Faba Bean ◽  
Rust Fungus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Rust Fungi ◽  
The Other ◽  
Two Dimensional ◽  
Bean Rust ◽  
Separate Species ◽  
Polypeptide Patterns ◽  
Uromyces Phaseoli

Proteins were extracted from urediospores of the bean rust fungus (Uromyces phaseoli var. typica: two isolates), of the cowpea rust fungus (U. phaseoli var. vignae; two isolates), and of the faba bean rust fungus (U. viciae-fabae; one isolate) and separated by two-dimensional isoelectric focusing – polyacrylamide gel electrophoresis under denaturing conditions. The two isolates of the cowpea rust fungus had identical polypeptide patterns; the two isolates of the bean rust fungus differed by 19 polypeptides. The polypeptide patterns of the bean rust, cowpea rust, and faba bean rust fungi differed markedly from each other. There were 277 polypeptides detected in extracts of the faba bean rust fungus, while more than 335 polypeptides were detected in extracts of each isolate of the other two fungi. While U. phaseoli var. typica and U. phaseoli var. vignae shared 183 polypeptides, U. viciae-fabae had only 149 and 146 polypeptides, respectively, in common with the other two rust fungi. This is consistent with the view that the two varieties of U. phaseoli are more closely related to each other than to U. viciae-fabae. However, when all detected polypeptides were compared, the differences between the two varieties were as extensive as those found between species. It is suggested, therefore, that the designation, by some mycologists of the cowpea rust fungus as a separate species, U. vignae, is correct.

Interactions of the bean rust and cowpea rust fungi with species of the Phaseolus – Vigna plant complex. I. Fungal growth and development

1987 ◽  
Vol 65 (6) ◽  
pp. 1096-1107 ◽  
Author(s):  
Janice F. Elmhirst ◽  
Michèle C. Heath
Keyword(s):  
Host Species ◽  
High Frequency ◽  
Growth And Development ◽  
Complex I ◽  
Fungal Growth ◽  
Rust Fungi ◽  
Uromyces Appendiculatus ◽  
Lablab Purpureus ◽  
Bean Rust ◽  
African Species

Growth and development of two closely related rust fungi, Uromyces appendiculatus and U. vignae (uredospore infections), were compared in several American and African species of the Phaseolus – Vigna plant complex and in Lablab purpureus. In plants inoculated with U. appendiculatus the frequency of formation of both primary and secondary haustoria generally decreased with evolutionary distance from the American host species. Uromyces appendiculatus formed primary haustoria at a high frequency of infection sites in most American and many African species, and also sustained a limited haustorium – plant cell metabolic relationship (as determined by the amount of secondary fungal growth) in one group of African species. Uromyces vignae generally formed very few haustoria in both American and African species not known as hosts of the fungus; however, growth of U. vignae colonies occasionally continued for some time at a few infection sites in nonhost species without sporulation. The implications of these results are discussed with respect to the coevolution of the two fungi with their hosts.

Effect of a Complex Heat Treatment on the Structure of 300M Steel

1981 ◽  
Vol 39 ◽  
pp. 312-313
Author(s):  
R. Padmanabhan ◽  
W. E. Wood
Keyword(s):  
Heat Treatment ◽  
Metal Carbides ◽  
Austenite Grain Size ◽  
300M Steel ◽  
Heat Treated ◽  
Strain Fracture ◽  
Prior Austenite Grain Size ◽  
Short Time ◽  
Final Tempering ◽  
Similar Yield

Intermediate high temperature tempering prior to subsequent reaustenitization has been shown to double the plane strain fracture toughness as compared to conventionally heat treated UHSLA steels, at similar yield strength levels. The precipitation (during tempering) of metal carbides and their subsequent partial redissolution and refinement (during reaustenitization), in addition to the reduction in the prior austenite grain size during the cycling operation have all been suggested to contribute to the observed improvement in the mechanical properties. In this investigation, 300M steel was initially austenitized at 1143°K and then subjected to intermediate tempering at 923°K for 1 hr. before reaustenitizing at 1123°K for a short time and final tempering at 583°K. The changes in the microstructure responsible for the improvement in the properties have been studied and compared with conventionally heat treated steel. Fig. 1 shows interlath films of retained austenite produced during conventionally heat treatment.

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