scholarly journals AN IMPROVED METHOD FOR ISOLATION OF THIELAVIOPSIS PARADOXA FROM STEM BLEEDING AFFECTED COCONUT PALMS

CORD ◽  
1991 ◽  
Vol 7 (01) ◽  
pp. 34 ◽  
Author(s):  
Anil Kumar ◽  
K.K.N. Nambiar
Keyword(s):  
Plant Pathogens ◽  
Improved Method ◽  
Isolation Method ◽  
Selective Media ◽  
Important Disease ◽  
Basic Necessity

Stem bleeding of coconut caused by Thielaviopsis paradoxa (de Seynes) Von Hohnel is an important disease affecting coconut in many countries (Menon and Pandalai, 1958; Ohler, 1966, Nambiar and Sastry, 1988). lsolation of the pathogen from diseased tissues on different agar based media has given inconsistent results (Anon., 1976; Anon., 1986), None of the selective media reported for certain related fungi viz., T. basicola (Berk and Br.) Ferr. (David, 1978;Tsao and Bricker, 1966) and Ceratocystis wagnerii Goheen and Cobb (Hicks et al., 1980) proved useful for the isolation of T. paradoxa Since, standardization of an isolation method is a basic necessity for any study on plant pathogens, an attempt was made to improve upon existing methods.

Differential isolation of Pythium species from soil by means of selective media, temperature, and pH

1975 ◽  
Vol 21 (5) ◽  
pp. 606-612 ◽  
Author(s):  
R. D. Lumsden ◽  
W. A. Ayers ◽  
R. L. Dow
Keyword(s):  
Gallic Acid ◽  
Acid Medium ◽  
Inoculum Potential ◽  
Pythium Species ◽  
Optimum Temperature ◽  
Isolation Method ◽  
Frequency Method ◽  
Plate Method ◽  
Selective Media ◽  
Mixed Populations

Pythium aphanidermatum, with an optimum temperature for growth at 35C, grew well and was readily isolated from soil on pimaricin–vancomycin medium (MPVM) when incubated for24 h at 38–40C. The pH of the medium affected recovery; maximum numbers developed above pH 6.0. Other Pythium spp. were recovered on MPVM at 20–25C, but were excluded by incubation at 38–40C. These Pythium spp. included P. ultimum, P. paroecandrum, P. irregulare, P. mamillatum, and an unidentified Pythium sp. These species grew well and were readily isolated from soil on gallic acid medium (GAM) when incubated for 24–48 h at 20C. P. aphanidermatum and P. myriotylum grew from mycelium on GAM, but their oospores did not germinate nor could they be isolated from soil on this medium. P. myriotylum grew well on MPVM, but was only rarely isolated, even from soils with known high potential for disease caused by P. myriotylum. Propagules of Pythium were enumerated by a plate-dilution frequency method or by a smear-plate method in serial dilutions of soil in 0.3% water agar. This differential isolation method is valuable for studies on the ecology, survival, and inoculum potential in soils with mixed populations of P. aphanidermatum and other Pythium spp.

scholarly journals Fluctuations of Phytophthora and Pythium spp. in Components of a Recycling Irrigation System

Plant Disease ◽  
2003 ◽  
Vol 87 (12) ◽  
pp. 1500-1506 ◽  
Author(s):  
Elizabeth A. Bush ◽  
Chuanxue Hong ◽  
Erik L. Stromberg
Keyword(s):  
Water Quality ◽  
Plant Pathogens ◽  
Management Practices ◽  
Irrigation System ◽  
Phytophthora Capsici ◽  
Selective Media ◽  
Irrigation Reservoir ◽  
Phytophthora Spp ◽  
Detection Technology ◽  
Pollutant Discharge

Stringent standards of water quality have prompted many horticultural enterprises to limit pollutant discharge associated with nutrient and pesticide applications. Collecting and recycling effluent is a method that has been implemented by many operations to contain pollutants; however, plant pathogens may be spread through recycled effluent. In this study, Phytophthora and Pythium spp. present in a water-recycling irrigation system at a perennial container nursery in southwestern Virginia were characterized using filtering and baiting techniques with two selective media. Members of Phytophthora were identified to species, whereas Pythium spp. were identified to genus only. Pythium spp. were recovered more frequently and in greater numbers than Phytophthora spp. Phytophthora capsici, P. citricola, P. citrophthora, P. cryptogea, P. drechsleri, and P. nicotianae were recovered in filtering assays. Only P. cryptogea and P. drechsleri were identified from baits placed on the surface of the irrigation reservoir, whereas P. cactorum, P. capsici, P. citricola, P. citrophthora, P. cryptogea, and P. drechsleri were recovered at depths, specifically at 1 and 1.5 m. This research provides data for development of detection technology and management practices for plant pathogens in irrigation water and may lead to improvements in conventional assay protocols.

scholarly journals Money Matters: Fueling Rapid Recent Insight Into Xylella fastidiosa—An Important and Expanding Global Pathogen

2019 ◽  
Vol 109 (2) ◽  
pp. 210-212 ◽  
Author(s):  
Steven Lindow
Keyword(s):  
Plant Pathogens ◽  
Xylella Fastidiosa ◽  
The United States ◽  
Economic Importance ◽  
Research Support ◽  
The World ◽  
Causal Pathogen ◽  
Insight Into ◽  
Important Disease ◽  
Recent Insight

Xylella fastidiosa has emerged from relative obscurity into one of the most well-studied bacterial plant pathogens. While Pierce’s disease of grape caused by this pathogen has been recognized as an important disease in warmer regions of the United States for nearly 100 years, the causal pathogen, X. fastidiosa has spread throughout much of the world and now also causes serious diseases of citrus, coffee, almond, olive, and other important crop plants. Our knowledge of this pathogen has been driven by the recent substantial research support justified by the economic importance of these diseases.

An Improved Method for the Preparation and TEM Examination of Sharp Pointed Tips used in APFIM and STM

1990 ◽  
Vol 48 (2) ◽  
pp. 102-103
Author(s):  
E.A. Fischione ◽  
P.E. Fischione ◽  
J.J. Haugh ◽  
M.G. Burke
Keyword(s):  
Atom Probe ◽  
Preparation Process ◽  
Improved Method ◽  
Ion Milling ◽  
Polishing Process ◽  
Probe Field ◽  
Scanning Tunnelling ◽  
Stm Tips ◽  
Tunnelling Microscopy ◽  
Ion Microscopy

A common requirement for both Atom Probe Field-Ion Microscopy (APFIM) and Scanning Tunnelling Microscopy (STM) is a sharp pointed tip for use as either the specimen (APFIM) or the probe (STM). Traditionally, tips have been prepared by either chemical or electropolishing techniques. Recently, ion-milling has been successfully employed in the production of APFIM tips [1]. Conventional electropolishing techniques are applicable to a wide variety of metals, but generally require careful manual adjustments during the polishing process and may also be time-consuming. In order to reduce the time and effort involved in the preparation process, a compact, self-contained polishing unit has been developed. This system is based upon the conventional two-stage electropolishing technique in which the specimen/tip blank is first locally thinned or “necked”, and subsequently electropolished until separation occurs.[2,3] The result of this process is the production of two APFIM or STM tips. A mechanized polishing unit that provides these functions while automatically maintaining alignment has been designed and developed.

Freeze substitution fixation of fungal reproductive structures and spores

1989 ◽  
Vol 47 ◽  
pp. 990-991
Author(s):  
C. W. Mims ◽  
E. A. Richardson
Keyword(s):  
Plant Pathogens ◽  
Freeze Substitution ◽  
Uranyl Acetate ◽  
Chemical Fixation ◽  
Dialysis Membrane ◽  
Razor Blade ◽  
Thin Sections ◽  
Reproductive Structures ◽  
Dry Down ◽  
Diamond Knife

The advantages of freeze substitution fixation over conventional chemical fixation for preservation of ultrastructural details in fungi have been discussed by various authors. As most ascomycetes, basidiomycetes and deuteromycetes do not fix well using conventional chemical fixation protocols, freeze substitution has attracted the attention of many individuals interested in fungal ultrastructure. Thus far most workers using this technique on fungi have concentrated on thin walled somatic hyphae. However, in our laboratory we have experimented with the use of freeze substitution on a variety of fungal reproductive structures and spores with promising results.Here we present data on freeze substituted samples of sporangia of the zygomycete Umbellopsis vinacea, basidia of Exobasidium camelliae var. gracilis, developing teliospores of the smut Sporisorium sorghi, germinating teliospores of the rust Gymnosporangium clavipes, germinating conidia of the deuteromycete Cercosporidium personatum, and developing ascospores of Ascodesmis nigricans.Spores of G. clavipes and C. personatum were deposited on moist pieces of sterile dialysis membrane where they hydrated and germinated. Asci of A. nigricans developed on pieces of dialysis membrane lying on nutrient agar plates. U. vinacea was cultured on small pieces of agar-coated wire. In the plant pathogens E. camelliae var. gracilis and S. sorghi, a razor blade was used to remove smal1 pieces of infected host issue. All samples were plunged directly into liquid propane and processed for study according to Hoch.l Samples on dialysis membrane were flat embedded. Serial thin sections were cut using a diamond knife, collected on slot grids, and allowed to dry down onto Formvar coated aluminum racks. Sections were post stained with uranyl acetate and lead citrate.

Immunoelectron microscopic localization of elastic tissue in archival material using an improved method

1990 ◽  
Vol 48 (3) ◽  
pp. 794-795
Author(s):  
J. C. Fanning ◽  
J. F. White ◽  
R. Polewski ◽  
E. G. Cleary
Keyword(s):  
Normal Animal ◽  
Animal Tissue ◽  
Elastic Tissue ◽  
Human Tissues ◽  
Improved Method ◽  
Tissue Samples ◽  
Archival Material ◽  
Immuno Electron Microscopy ◽  
Arteries And Veins ◽  
Biochemical Examination

Elastic tissue is an important component of the walls of arteries and veins, of skin, of the lungs and in lesser amounts, of many other tissues. It is responsible for the rubber-like properties of the arteries and for the normal texture of young skin. It undergoes changes in a number of important diseases such as atherosclerosis and emphysema and on exposure of skin to sunlight.We have recently described methods for the localizationof elastic tissue components in normal animal and human tissues. In the study of developing and diseased tissues it is often not possible to obtain samples which have been optimally prepared for immuno-electron microscopy. Sometimes there is also a need to examine retrospectively samples collected some years previously. We have therefore developed modifications to our published methods to allow examination of human and animal tissue samples obtained at surgery or during post mortem which have subsequently been: 1. stored frozen at -35° or -70°C for biochemical examination; 2.

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