The development, structure, and histochemistry of sclerotia of ectomycorrhizal fungi. II. Paxillus involutus

1985 ◽  
Vol 63 (8) ◽  
pp. 1412-1417 ◽  
Author(s):  
D. J. Grenville ◽  
R. L. Peterson ◽  
Y. Piché

Sclerotia of Paxillus involutus (Batsch) Fr. were produced in association with Pinus strobus L. and Pinus resinosa Ait. in plastic growth pouches and on agar-solidified nutrient medium. They were fixed and embedded for light microscopy and scanning and transmission electron microscopy. Sclerotia consisted of an outer pigmented rind, a thin cortical layer, and a large central medulla of isodiametric cells. Large deposits of glycogen, as well as smaller deposits of protein and lipid, were present in medullary and cortical cells. Structural characteristics indicate that these sclerotia are persistent propagules which may function to reinfect tree roots following environmental stresses. Since they can be produced in pure culture, it may be possible to inoculate seedlings directly with sclerotia.


1985 ◽  
Vol 63 (8) ◽  
pp. 1402-1411 ◽  
Author(s):  
D. J. Grenville ◽  
R. L. Peterson ◽  
Y. Piché

Sclerotia were produced by growing Pisolithus tinctorius (Pers.) Coker and Couch in association with Pinus strobus L. and Pinus resinosa Ait. in plastic growth pouches. Developing and mature sclerotia were collected, fixed, and embedded for light microscopy and scanning and transmission electron microscopy. They were found to consist of an outer pigmented rind, an inner and outer cortex, and a large central medulla. Cortical and medullary areas were comprised of pseudoparenchyma which contained large deposits of glycogen, as well as protein and lipids. The structure of these sclerotia indicates that they are persistent propagules. Sclerotia may be important in nature for the recolonization of root tips after environmental stresses. They may also be useful for storing valuable strains of P. tinctorius and as a source of inoculum for experimental studies.



Author(s):  
R. Gronsky

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.





2011 ◽  
Vol 194-196 ◽  
pp. 594-597
Author(s):  
Ke Tang ◽  
Xin Hong ◽  
Jin Gang Qi

FAU-type(NaY) zeolites nanocrystals have been synthesized through crystallization of gel in mesoporous system of carbon nanotubes(CNTS) with a internal diameter of 20~30 nm. Investigation by using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscope (TEM) shows that the nanocrystals possess the typical nanosized zeolites structural characteristics which is different from those of microsized zeolites.



1988 ◽  
Vol 66 (6) ◽  
pp. 1080-1090 ◽  
Author(s):  
Mark R. Roberts ◽  
Norman L. Christensen

Vegetation composition of the shrub–tree and herb layers was sampled in 70 successional aspen (Populus tremuloides and Populus grandidentata) stands of different ages (1–90 years) on a variety of sites in northern lower Michigan. Physical and chemical characteristics of soil profiles were also measured at each site. Three stand groupings were identified based on site conditions and detrended correspondence analysis (DCA) ordination of the vegetation. Sandy dry-mesic soils support forests of Acer rubrum, Quercus rubra, Pinus resinosa, and Pinus strobus. On lowland sandy soils with a fluctuating water table, Pinus strobus, Abies balsamea, Viburnum lentago, and Viburnum cassinoides are important. Mesic soils with stratified calcareous layers or clay till substrates support Acer saccharum, Fagus grandifolia, Tilia americana, Fraxinus americana, Ostrya virginiana, and Acer pensylvanicum. Canonical correlation analysis (CCA) was used to compare DCA scores with soil variables; first-axis DCA scores were correlated with a suite of soil variables and stand age was correlated with second or third DCA axis scores. Separate DCA ordinations of the dry-mesic and mesic groups revealed successional relations on these sites. On dry-mesic sites, Pinus resinosa and Pinus strobus increase in importance with stand age, while Prunus serotina, Prunus virginiana, Prunus pensylvanica, and the aspens decrease. On mesic sites, early successional species include the aspens, Corylus cornuta, Prunus serotina, and Prunus pensylvanica. Fagus grandifolia, Acer pensylvanicum, Quercus rubra, Viburnum acerifolium, Betula papyrifera, Acer rubrum, and Tilia americana are more abundant in mature mesic-site stands. Ordinations of the herb data were remarkably similar to those for trees and shrubs except on dry-mesic sites. Much of the residual variability in vegetation not accounted for by site conditions and stand age is probably related to historical factors such as the nature of disturbance and variations in seed rain.



2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Elena Stocco ◽  
Silvia Barbon ◽  
Veronica Macchi ◽  
Cesare Tiengo ◽  
Lucia Petrelli ◽  
...  

AbstractNerve wrapping improves neurorrhaphy outcomes in case of peripheral nerve injuries (PNIs). The aim of this preclinical study was to assess the efficacy of two novel biodegradable wraps made of a synthetic 1% oxidized polyvinyl alcohol (OxPVA) and a natural leukocyte-fibrin-platelet membrane (LFPm) versus the commercial product NeuraWrap. After rats sciatic nerve transection and neurorrhaphy, the wraps were implanted and compared for functional outcome, by sciatic function index assessment; structural characteristics, by histological/immunohistochemical analysis; ultrastructural features, by transmission electron microscopy. Moreover, a morphometric study was also performed and collagen distribution was observed by Second Harmonic Generation microscopy. After 12 weeks from implantation, all wraps assured nerve function recovery; no scar tissue/neuromas were visible at dissection. LFPm wraps were completely resorbed, while residues of OxPVA and NeuraWrap were observed. In all groups, biocompatibility was confirmed by the absence of significant inflammatory infiltrate. According to histological/immunohistochemical analysis and morphometric findings, OxPVA and LFPm wraps were both effective in preserving nerve integrity. These results assess that bioengineered OxPVA and LFPm wraps successfully guarantee favorable lesion recovery after PNI/neurorrhaphy and, in future, may be considered an interesting alternative to the commercial NeuraWrap.



Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1117 ◽  
Author(s):  
Lung-Chien Chen ◽  
Ching-Ho Tien ◽  
Sin-Liang Ou ◽  
Kun-Yi Lee ◽  
Jianjun Tian ◽  
...  

Perovskite CsPbBr3 quantum dot (CsPbBr3-QD) recovery was performed using lead scrap from lead storage batteries. The perovskite CsPbBr3-QD characteristics were analyzed using different PbO/recycled PbO2 ratios. Scanning electron microscopy (SEM) was used to observe the film surface morphology and cross-section. High-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) were used to observe the perovskite CsPbBr3-QDs’ structural characteristics. A photoluminescence (PL) measurement system was used to analyze the optical properties. The results show that lead scrap from lead–acid batteries as a material for perovskite CsPbBr3-QD production can be successfully synthesized. This saves material and also proves that recycling is valuable. The proposed approach is helpful for future material shortages and materials not easily accessible. Although the efficiency is not very high, this process will be purified using recycled lead in the future to achieve higher quantum yield.



1941 ◽  
Vol 28 (2) ◽  
pp. 175-177 ◽  
Author(s):  
John W. Duffield ◽  
Albert G. Snow


1980 ◽  
Vol 58 (23) ◽  
pp. 2421-2433 ◽  
Author(s):  
T. A. Peterson ◽  
W. C. Mueller ◽  
L. Englander

Light and electron microscopic investigations of the roots of Rhododendron and other ericaceous plants growing in the vicinity of Clavaria fruiting structures showed a fungal infection consistently associated with the epidermal and cortical cells of the "hair roots." Uninfected hair roots consisted of an epidermis and a one cell thick cortical layer surrounding the stele. Secondary growth in the stele and formation of a cork layer by division of the pericycle caused the cortex and epidermis to slough as the root matured. The structure of the infected hair roots was similar except for the presence of fungus in epidermal and cortical cells. As judged by the appearance of septa, at least two fungi were involved, one with dolipore septa that formed hyphal coils in the infected cells, and one with septa associated with Woronin bodies that occurred as single hyphal strands. Hyphae were found penetrating the cells from the exterior of the root and also passing from cell to cell. No correlation between fungal infection and the phenolic content of the cells could be made. Dissolution of both the fungal and host cytoplasm appeared to occur as the cells were sloughed. It appears that the fungus–root relationship is complex and is limited in duration to a short period of time during the development of the hair roots.



2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Xuemeng Dong ◽  
Chenguang Liu

Novel amphiphilic biopolymers were synthesized using hyaluronic acid (HA) as a hydrophilic segment and deoxycholic acid (DOCA) as a hydrophobic segment by a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide mediated coupling reaction. The structural characteristics of the HA-DOCA conjugates were investigated usingH1NMR. Self-assembled nanoparticles were prepared based on HA-DOCA conjugates, and its characteristics were investigated using dynamic laser light scattering, transmission electron microscopy (TEM), and fluorescence spectroscopy. The mean diameter was about 293.5 nm with unimodal size distribution in distilled water. The TEM images revealed that the shape of HA-DOCA self-aggregates was spherical. The critical aggregation concentration (CAC) was in the range of 0.025–0.056 mg/mL. The partition equilibrium constant (Kv) of pyrene in self-aggregates solution was from1.45×104to3.64×104. The aggregation number of DOCA groups per hydrophobic microdomain, estimated by the fluorescence quenching method using cetylpyridinium chloride, increased with increasing degree of substitution.



Sign in / Sign up

Export Citation Format

Share Document