A study of fungal endoparasitism of the cereal cyst nematode (Heterodera avenae) by scanning electron microscopy

1988 ◽  
Vol 34 (5) ◽  
pp. 613-619 ◽  
Author(s):  
L. V. Lopez-Llorca ◽  
G. H. Duncan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Cyst Nematode ◽  
Cereal Cyst Nematode ◽  
Heterodera Avenae ◽  
Natural State ◽  
Sequential Development ◽  
Nematode Eggs ◽  
Scanning Electron

The sequential development of fungal endoparasites from eggs of the cereal cyst nematode (Heterodera avenae) was studied by scanning electron microscopy using both critical point dried and frozen, fully hydrated specimens. Fully hydrated specimens were much closer to the natural state than those that had been critical-point dried. Several stages of fungal infection were observed that are similar to those reported for entomopathogenic fungi. Cereal cyst nematode eggs from white females or from cysts were examined before plating on agar. Eggs from both sources had two distinct shapes. This was caused by differences in the developmental stage of the eggs from white females and by the presence or absence of internal fungal material in eggs from cysts.

Effects of fungal parasites on cereal cyst nematode (Heterodera avenae Woll.) from naturally infested soil—a scanning electron microscopy study

1991 ◽  
Vol 37 (3) ◽  
pp. 218-225 ◽  
Author(s):  
L. V. Lopez-Llorca ◽  
G. H. Duncan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Early Stage ◽  
Cyst Nematode ◽  
Infection Process ◽  
Cereal Cyst Nematode ◽  
Heterodera Avenae ◽  
Infested Soil ◽  
Fungal Parasites ◽  
Scanning Electron

The effects of fungal endoparasites, attacking the eggs of the cereal cyst nematode Heterodera avenae, and details of the infection process were studied by low-temperature scanning electron microscopy. Some female nematodes, even young ones containing no eggs, were colonized by fungi. Spores and hyphae similar to those of Nematophthora gynophila were found in infected specimens. Fungi colonized both roots and nematodes. In early stages of infection, fungi developed within the female nematode between the organs, presumably using the female's body as a food source. In some immature females, the fungi appeared to have destroyed the uterus. In old females, appressoria of Verticillium spp., including V. chlamydosporium, penetrated the eggs they contained and progressively destroyed their contents until the egg shell was filled with hyphae and spores. Only rarely were second-stage juveniles within eggs infected by these fungi. Fungal infection of eggs, which arrests their development at an early stage, therefore occurs predominantly in females rather than in newly formed cysts. Key words: Heterodero avenae, fungal parasites, naturally infested soil, scanning electron microscopy.

Preservation of Plant Cell Surfaces For Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 472-473
Author(s):  
Linda M. Sicko ◽  
Thomas E. Jensen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Filter Paper ◽  
Freeze Drying ◽  
Cell Surfaces ◽  
Air Drying ◽  
Popular Method ◽  
Critical Point Drying ◽  
Scanning Electron

The use of critical point drying is rapidly becoming a popular method of preparing biological samples for scanning electron microscopy. The procedure is rapid, and produces consistent results with a variety of samples. The preservation of surface details is much greater than that of air drying, and the procedure is less complicated than that of freeze drying. This paper will present results comparing conventional air-drying of plant specimens to critical point drying, both of fixed and unfixed material. The preservation of delicate structures which are easily damaged in processing and the use of filter paper as a vehicle for drying will be discussed.

Scanning Electron Microscopy of Dried and Acid Treated Shells of Difflugia

1973 ◽  
Vol 31 ◽  
pp. 448-449
Author(s):  
Barry S. Eckert ◽  
S. M. McGee-Russell
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Point Method ◽  
External Structure ◽  
Cell Locomotion ◽  
Single Opening ◽  
Scanning Electron

Difflugia lobostoma is a shelled amoeba. The shell is an external structure of considerable mass which presents the animal with special restrictions in cell locomotion which are met by the development of active pseudopodial lobopodia containing, apparently, an organized system of thick and thin microfilaments (Eckert and McGee-Russell, 1972). The shell is constructed of sand grains picked up from the environment, and cemented into place with a secretion. There is a single opening through which lobopods extend. The organization of the shell was studied by scanning electron microscopy (SEM).Intact shells or animals with shells were dried by the critical point method of Anderson (1966) or air dried, after primary fixation in glutaraldehyde.

scholarly journals A Review Of The Development Of Scanning Electron Microscopy At High Chamber Pressure

1997 ◽  
Vol 5 (1) ◽  
pp. 14-15
Author(s):  
Vivian Robinson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Chamber Pressure ◽  
Natural State ◽  
Specimen Preparation ◽  
Electron Microscopes ◽  
Reproducible Manner ◽  
Scanning Electron

Ever since electron microscopes were developed, it has been the goal of microscopists to observe specimens in their natural state, free from artefacts which can often be introduced through specimen preparation. For most biological specimens, that includes the presence of water. With a pressure of 10-4 torr or lower required to operate a scanning electron microscope (SEM), liquid water, which required a pressure of above 5 torr, was clearly a problem.Although several attempts had been made to examine hydrated specimens in a SEM, the first published results of water imaged in a stable and reproducible manner in the SEM, were presented at the Eighth International Congress on Electron Microscopy in Canberra in 1974 (Robinson, 1974).

Sign in / Sign up

Export Citation Format

Share Document