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.

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.

Effect of sedimentary environment on shale lithofacies in the lower third member of the Shahejie Formation, Zhanhua Sag, eastern China

2017 ◽  
Vol 5 (4) ◽  
pp. T487-T501 ◽  
Author(s):  
Tingwei Li ◽  
Zhenxue Jiang ◽  
Chenlu Xu ◽  
Yuan Yuan ◽  
Pengfei Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Early Stage ◽  
Eastern China ◽  
Sedimentary Environment ◽  
Gas Production ◽  
Bohai Bay ◽  
Calcareous Shale ◽  
Shahejie Formation ◽  
Scanning Electron

Research on shale lithofacies is important for shale oil and gas production. This study focused on the lower third member of the Shahejie Formation ([Formula: see text]) in the Luo-69 well in the Zhanhua Sag, Jiyang Depression, Bohai Bay Basin, eastern China. Several methods, including thin section observations, total organic carbon (TOC) analysis, X-ray diffraction analysis, quantitative evaluations of minerals by scanning electron microscopy, major and trace-element analyses, and field emission-scanning electron microscopy, are used to investigate the effect of sedimentary environment on the type and distribution of shale lithofacies. Our research indicates that 36 types of shale lithofacies can be classified based on the TOC content, mineral composition, and sedimentary structure, of which five types are identified in the study area. The [Formula: see text] shale has a high calcareous mineral content (average of 49.64%), low clay and siliceous minerals contents (averages of 19.54% and 19.02%, respectively), a high TOC content (average of 3.00 wt%), and well-developed horizontal bedding. The sedimentary environment during the deposition of the [Formula: see text] shale in the Zhanhua Sag had a warm and moist climate, limited provenance, saline water, and strong reducibility. The sedimentary environment in the early stage had a drier climate, more limited provenance, higher salinity, and stronger reducibility than that in the later stage. Shale lithofacies can reflect a certain sedimentary environment and depositional process; similarly, a depositional environment controls the type and distribution of shale lithofacies. Due to the characteristics of the [Formula: see text] sedimentary environment, organic-rich massive mixed shale, organic-rich bedded mixed-calcareous shale, organic-rich laminated calcareous shale, and organic-fair laminated calcareous shale are developed in the [Formula: see text] formation from top to bottom.

scholarly journals Environmental Scanning Electron Microscopy of the Infection Process of Fusarium solani f. sp. passiflorae in Seedlings of Passionfruit (Passiflora edulis f. flavicarpa)

2017 ◽  
Vol 41 (159) ◽  
pp. 213
Author(s):  
Jacobo Robledo-Buriticá ◽  
Carolina Ángel-García ◽  
Jairo Castaño-Zapata
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fusarium Solani ◽  
Environmental Scanning Electron Microscopy ◽  
Infection Process ◽  
Environmental Scanning ◽  
Passiflora Edulis ◽  
Scanning Electron

Se realizó microscopía electrónica de barrido ambiental (ESEM) en plántulas de maracuyá (Passiflora edulis f. flavicarpa) inoculadas con Fusarium solani f. sp. passiflorae (teleomorfo: Haematonectria haematococca) agente causal de la secadera. Las inoculaciones se realizaron cada 24 h hasta el séptimo día y hasta el día quince el intervalo fue de 72 h. El aislamiento en medio de papa (PDA) se colocó sobre el cuello de la raíz mediante la metodología de cribado en tubos de ensayo modificada. La superficie del cuello, tallo, hojas y secciones longitudinales del cuello y tallo fueron observadas. Después de 24 h de la inoculación, se observaron conidios y micelio denso septado sobre la epidermis del tallo y el cuello e hipertrofia y degradación de la pared celular de los tejidos vasculares. Al quinto día se formaron macroconidios a partir de monofiálides en el micelio aéreo en el tallo. Diez días después, las células del xilema y médula del cuello fueron colonizadas por hifas, esporodoquios maduros e inclusiones. La colonización de las estomas por las hifas comenzó seis días después de la inoculación y trece días después de la inoculación se observaron monofiálides con microconidios in situ sobre la superficie foliar. Basados en la evidencia y estudios previos, la colonización interna por hifas de F. solani f. sp. passiflorae se concentra en el área del cuello y los daños de las células indican una actividad enzimática extracelular del hongo. El periodo de incubación y latencia de F. solani f. sp. passiflorae fue de 1,4 y 4 días, respectivamente. © 2017. Acad. Colomb. Cienc. Ex. Fis. Nat.

scholarly journals Experimental Study On Antibacterial Properties of Iodine-Coated Implant in Acute Osteomyelitis Model

2021 ◽  
Author(s):  
Xiqi Zhuang ◽  
Weibing Yang ◽  
Yongquan Zhang ◽  
Wanming Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Early Stage ◽  
Antibacterial Properties ◽  
Bacterial Suspension ◽  
Acute Osteomyelitis ◽  
Marrow Cavity ◽  
Coated Implant ◽  
K Wires ◽  
Scanning Electron

Abstract Purpose We have developed a iodine-coated implant and evaluated its antibacterial properties against Gram-negative bacteria by constructing an experimental osteomyelitis model.Methods In this study, 16 titanium Kirschner-wires were selected, of which 8 titanium K-wires were treated with iodine on the surface by electrophoretic deposition with PVP-I solution. In our study, the standard strain of Escherichia coli (ATCC 25922) was selected, and 16 New Zealand rabbits were selected. There were 8 rabbits in the iodine-coated group and 8 rabbits in the non-iodine-coated group. All animals were drilled in the left proximal tibia after successful anesthesia.After that,the iodine-coated group was implanted with iodine-coated titanium K-wires.Then, 25ul of 2×108CFU/ml bacterial suspension was injected into the bone marrow cavity with pipette gun, and the bone hole was sealed with bone wax.They were reared in cages for 1 week after operation, and evaluated and analyzed by microbiology, histopathology, scanning electron microscopy, etc.Results The results of gross wound score and microbiology showed that the wound infection of the iodine-coated group was less severe than that of the non-iodine-coated group, which was confirmed by the histopathological results. Scanning electron microscopy and confocal microscopy showed that the amount of bacteria on the surface of iodine-coated K-wires was significantly lower than that non-iodine-coated K-wires. Conclusions In this study, we have verified that the iodine-coated titanium implant could effectively inhibit E. coli infection in the early stage of infection by constructing an acute osteomyelitis model.

scholarly journals Characterization of the infection process by Peronospora belbahrii on basil by scanning electron microscopy

Heliyon ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. e01117 ◽  
Author(s):  
Guirong Zhang ◽  
Arthur Thompson ◽  
David Schisler ◽  
Eric T. Johnson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Infection Process ◽  
Scanning Electron

Processibility and Thermo-Mechanical Properties of Epoxy as Reactive Plasticizer of Polyetherimide

2017 ◽  
Vol 264 ◽  
pp. 228-231
Author(s):  
Nasuha Marzuki ◽  
Muhamad Amirul Ashraf Mohd Alias ◽  
Arjulizan Rusli ◽  
Zulkifli Ahmad
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Early Stage ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Dispersed Particles ◽  
Epoxy Blends ◽  
Scanning Electron

A relatively new way to improve processibility thermoplastics is via the use of crosslinkable monomers which can act as reactive plasticizers and reduce the viscosity in the early stage of processing. The monomers can polymerize and phase separate during final stage of processing thus recovering the original thermoplastics properties. In this work, the applicability of epoxy as reactive plasticizer for polyetherimide (PEI) was investigated. The properties of PEI/epoxy blends without and with curative were studied in order to determine the effect of the monomer on the processibility of the PEI and the thermo-mechanical properties of cured blends. Differential Scanning Calorimetry on blends without curative indicated single glass transition temperature (Tg) at high PEI content suggesting miscibility of the system and plasticization of PEI in the presence of epoxy while cured blends indicated two Tg due to phase separation. Scanning electron microscopy of the cured blends indicated two phase morphology with PEI dispersed particles size increased in continuous epoxy matrix with increasing PEI (up to 30wt% PEI). In blends with 40wt% PEI and more, phase inverted morphology was observed where increasing PEI content caused reduction of epoxy particle size in continuous PEI matrix.

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