scholarly journals Resolution and analysis of ‘native’ and ‘activated’ properdin

1987 ◽  
Vol 243 (2) ◽  
pp. 507-517 ◽  
Author(s):  
T C Farries ◽  
J T Finch ◽  
P J Lachmann ◽  
R A Harrison
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Alternative Pathway ◽  
Gel Filtration ◽  
Alternative Activation ◽  
Functional Heterogeneity ◽  
Native Population ◽  
Physiological Event ◽  
Effective Screening

A rapid and reproducible procedure for the resolution of ‘native’ and ‘activated’ forms of properdin (a component of the alternative activation pathway of complement), by gel filtration on the polyvinyl matrix Fractogel TSK HW-55(S), is reported. This fractionation permitted effective screening of samples for conditions that cause activation. Only ‘native’ properdin was detected in serum, even after activation of the alternative pathway by yeast cell walls. Transformation of ‘native’ into ‘activated’ properdin in vitro was produced by freeze-thawing of the protein, but not upon binding to and dissociation from the C3 convertase, C3bBb. Electron microscopy showed that only the ‘native’ population contained the discrete cyclic structures described previously by Smith, Pangburn, Vogel & Müller-Eberhard [(1984) J. Biol. Chem. 259, 4582-4588]. ‘Activated’ properdin, which was eluted from the gel-filtration column close to the breakthrough peak, was mainly composed of large amorphous aggregates. We therefore conclude that properdin ‘activation’ is not a physiological event that occurs in serum on complement activation, but is an artifact of isolation. Fractionation of properdin on Fractogel TSK HW-55(S) has, however, enabled detailed analysis of functional heterogeneity within the ‘native’ population.

scholarly journals The influence of jasmonic acid on the amount and the distribution of cysteine proteinase PLCP-2 in healthy and PVYNTN infected potato plants (Solanum tuberosum L.)

2002 ◽  
Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽  
pp. S95-S98
Author(s):  
M. Pompe-Novak ◽  
M. Tušek-Žnidarič ◽  
B. Štrukelj ◽  
M. Ravnikar
Keyword(s):  
Electron Microscopy ◽  
Solanum Tuberosum ◽  
Jasmonic Acid ◽  
Cell Walls ◽  
Cysteine Proteinase ◽  
Solanum Tuberosum L ◽  
Cell Types ◽  
Protein Bodies ◽  
Potato Plants

The localization of cysteine proteinase PLCP-2 was investigated in potato plants (Solanum tuberosum L.) cultivar Désirée by electron microscopy. Healthy and PVY<sup>NTN</sup> infected potato plants were grown in vitro on media with or without a supplement of jasmonic acid. We had already shown that PLCP-2 is present in leaves, stems, tips of shoots and tips of roots of healthy and PVY<sup>NTN</sup> infected plants. It was detected in various cell types in protein bodies in vacuoles, in cytoplasm and in cell walls. There were significantly larger amounts of PLCP-2 in plants grown on medium with a supplement of jasmonic acid in both healthy and virus infected plants. More protein bodies in vacuoles were found in plants grown on medium with addition of jasmonic acid.

Characterization of a protein-lipopolysaccharide complex released from cell walls of Pseudomonas aeruginosa by ethylenediaminetetraacetic acid

1969 ◽  
Vol 15 (7) ◽  
pp. 743-748 ◽  
Author(s):  
S. W. Rogers ◽  
H. E. Gilleland Jr. ◽  
R. G. Eagon
Keyword(s):  
Electron Microscopy ◽  
Pseudomonas Aeruginosa ◽  
Cell Walls ◽  
Ethylenediaminetetraacetic Acid ◽  
Gradient Centrifugation ◽  
Hollow Spheres ◽  
Gel Filtration ◽  
A Chain ◽  
Ultracentrifugal Analysis

Results from analytical ultracentrifugal analysis, Sephadex gel filtration, isopycnic density-gradient centrifugation, and polyacrylamide disc-gel electrophoresis revealed that ethylenediaminetetraacetic acid liberated a protein–lipopolysaccharide complex from cell walls of Pseudomonas aeruginosa with an estimated molecular weight of not less than 160 000 and probably about one million. Electron microscopy of this complex revealed spherules and rodlets. The diameter of the former was approximately 70 ± 10 Å while the dimensions of the latter were 70 ± 10 Å × 200 ± 50 Å. The rodlets appeared to be composed of three or more spherules arranged in a chain-like fashion. Electron microscopy of protein-free lipopolysaccharide revealed predominantly hollow spheres from 300 Å to 1500 Å in diameter, morphologically resembling membrane sacculi. It is proposed that the protein–lipopolysaccharide complex, but not the protein-free lipopolysaccharide, is representative of the in situ form of native endotoxin.

Ultrastructure and influences of temperature on the in vitro production of Coprinus psychromorbidus sclerotia

1987 ◽  
Vol 65 (1) ◽  
pp. 124-130 ◽  
Author(s):  
James A. Traquair ◽  
Denis A. Gaudet ◽  
Eric G. Kokko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Walls ◽  
Colony Growth ◽  
In Vitro Production ◽  
Intercellular Matrix ◽  
Sclerotium Production ◽  
First Time ◽  
Scanning Electron

The effects of temperature on the production of sclerotia by the snow mold basidiomycete, Coprinus psychromorbidus, are described for the first time. Numbers of sclerotia produced and the optimum temperature for sclerotium production were variable for isolates observed. In general, the influence of temperature on sclerotium production was independent of its influence on colony growth. Optimal temperatures for production of sclerotia were higher than those for radial growth of colonies. Scanning electron microscopy revealed a centripetal pattern of differentiation in developing sclerotia. Distinctive rind, cortex, and medulla were evident after 8 to 10 weeks. Rind and cortex were multilayered. Thick-walled cells were cemented together by an amorphous intercellular matrix. Melanin was located in the rind cell walls for the first time by scanning electron microscopy and backscattered electron imaging of silver-stained sections. With the transmission electron microscope, melanin granules were observed only in the intercellular matrix and outer layers of rind cell walls. Inflated medullary cells were predominantly thin walled and contained vacuolate cytoplasm.

scholarly journals Evidence of a defined spatial arrangement of hyaluronate in the central filament of cartilage proteoglycan aggregates

1995 ◽  
Vol 307 (2) ◽  
pp. 595-601 ◽  
Author(s):  
M Mörgelin ◽  
M Paulsson ◽  
D Heinegård ◽  
U Aebi ◽  
J Engel
Keyword(s):  
Electron Microscopy ◽  
Core Protein ◽  
Gel Filtration ◽  
Spatial Arrangement ◽  
Link Protein ◽  
Original Length ◽  
Central Filament ◽  
Proteoglycan Aggregates ◽  
Rotary Shadowing

Aggregates of proteoglycans from the Swarm rat chondrosarcoma reassembled in vitro have been studied by rotary-shadowing electron microscopy, and shown to be similar to native structures that have never been dissociated [Mörgelin, Engel, Heinegård and Paulsson (1992) J. Biol. Chem. 267, 14275-14284]. A hyaluronate with defined chain length (HAshort) has now been prepared by autoclaving high-Mr hyaluronate and fractionation to a narrow size distribution by gel filtration. Proteoglycan monomers, core protein, hyaluronate-binding region and link protein were combined with HAshort. Free chains of HAshort and reconstituted complexes with proteoglycan, link protein and aggrecan fragments were examined by electron microscopy after rotary shadowing. Length measurements showed that the hyaluronate was condensed to about half of its original length on binding intact aggrecan monomers, any aggrecan fragment or link protein alone. This strongly implies that hyaluronate adopts a defined spatial arrangement within the central filament of the aggregate, probably different from its secondary structure in solution. No differences in length were observed between link-free and link-stabilized aggregates.

In vitro anti-Pythium insidiosum activity of biogenic silver nanoparticles

2018 ◽  
Vol 57 (7) ◽  
pp. 858-863 ◽  
Author(s):  
Júlia de Souza Silveira Valente ◽  
Caroline Quintana Braga ◽  
Carolina Litchina Brasil ◽  
Cristiane Telles Baptista ◽  
Guilherme Fonseca Reis ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
In Vitro Assays ◽  
Pythium Insidiosum ◽  
Biogenic Silver Nanoparticles ◽  
Transmission Electron ◽  
Cellular Wall ◽  
Scanning Electron

AbstractPythium insidiosum belongs to the phylum Oomycota. It is capable of infecting mammals causing a serious condition called pythiosis, which affects mainly horses in Brazil and humans in Thailand. The objective of the present study was to verify the in vitro anti-P. insidiosum activity of a biogenic silver nanoparticle (bio-AgNP) formulation. The in vitro assays were evaluated on P. insidiosum isolates (n = 38) following the M38-A2 protocol. Damage to the P. insidiosum hyphae ultrastructure was verified by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Bio-AgNP inhibition concentrations on P. insidiosum isolates ranged from 0.06 to 0.47 μg/ml. It was observed through SEM that P. insidiosum hyphae treated showed surface roughness, as well as cell walls with multiple retraction areas, loss of continuity, and rupture in some areas. The TEM of treated hyphae did not differentiate organelle structures; also, the cellular wall was rarefied, showing wrinkled and partly ruptured borders. The bio-AgNP evaluated has excellent in vitro anti-P. insidiosum activity. However, further studies on its in vivo action are necessary as so to determine the possibility of its use in the treatment of the disease in affected hosts.

Interactions hôte–parasite lors de l'infection par Cercosporella herpotrichoides, agent du piétin-verse : morphologie du parasite et ultrastructure des parois d'hôtes sensibles et résistants

1985 ◽  
Vol 63 (5) ◽  
pp. 851-858 ◽  
Author(s):  
Marie-Christine Soulie ◽  
Brigitte Vian ◽  
Thérèse Guillot-Salomon
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ultrastructural Study ◽  
Cell Walls ◽  
Virulent Strain ◽  
Host Cells ◽  
Resistant Lines ◽  
Strong Adhesion ◽  
Scanning Electron

Segments of seedlings of susceptible and resistant lines of Triticineae were infected in vitro by a virulent strain of Cercosporella herpotrichoides Fron. Samples were taken 4 days after inoculation and examined using scanning electron microscopy. In susceptible lines, a strong adhesion and an important development of the mycelium occurred in contact with the coleoptile. Simultaneously, a massive sporulation was observed. Conversely, in resistant lines, the hyphal stroma remained loose and poorly developed and failed to sporulate. A cytochemical and ultrastructural study of the walls of host cells showed changes in texture and an important deposition of strongly reactive compounds. These components could not be extracted by the usual solvents of matrix constituents of both cellulosic and lignified cell walls. An enhanced synthesis of such substances could prevent the action of the parasite glycolytic enzymes and therefore stop the fungal invasion. The wall, or at least some of its components, seems to be implicated both in the recognition of the pathogen by the host and in the triggering of a response leading to sequestration of the latter and arrest in its development.

Ultrastructure of stromatal anamorphs in the Sclerotiniaceae

1989 ◽  
Vol 67 (2) ◽  
pp. 394-406 ◽  
Author(s):  
Linda M. Kohn ◽  
Douglas J. Grenville
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Walls ◽  
Monilinia Fructicola ◽  
Cellular Organization ◽  
Ultrastructural Studies ◽  
Sclerotium Cepivorum ◽  
Transmission Electron ◽  
Septal Pores

As part of comparative anatomical, histochemical, and ultrastructural studies of stromata in the Sclerotiniaceae, mature stromata produced in vitro by 11 species representing six genera and one form-genus were examined using transmission electron microscopy. Sclerotial-stromatal taxa were Sclerotinia sclerotiorum, S. trifoliorum, S. minor, Sclerotium cepivorum, Botrytis cinerea, B. porri, Monilinia fructicola, and Myriosclerotinia borealis. Substratal-stromatal taxa were Sclerotinia homoeo-carpa, Rutstroemia sydowiana, and Lambertella subrenispora. Three types of rind were observed: a living cellular rind, a dead cellular rind, and a stromatal rind. Sclerotial species were distinguished from stromatal species not only by the rind type, but also by the confluent extracellular matrix around cortical and medullary cell walls. Presence of lacunae in this matrix distinguished Sclerotinia spp. and M. borealis from Botrytis spp. and Monilinia fructicola. Rind, cortical, and medullary cells contained abundant storage vacuoles in most taxa. The distribution and proportion of organelles to storage vacuoles differed among taxa. Plugged septal pores with associated Woronin bodies were similar among the taxa where they were observed. Sclerotia of Sclerotium cepivorum, which has no known teleomorph, are ultrastructurally most like sclerotia of Sclerotinia or Botrytis anamorphs of Botryotinia species. Substratal stromata of S. homoeocarpa showed unusually complex cellular organization. Sclerotial stromata of M. fructicola contained unusual storage vacuoles with heterogeneous contents.

scholarly journals Saprotrophic and Mycoparasitic Components of Aggressiveness of Trichoderma harzianum Groups toward the Commercial Mushroom Agaricus bisporus

2003 ◽  
Vol 69 (7) ◽  
pp. 4192-4199 ◽  
Author(s):  
Josie Williams ◽  
John M. Clarkson ◽  
Peter R. Mills ◽  
Richard M. Cooper
Keyword(s):  
Electron Microscopy ◽  
Wheat Straw ◽  
Trichoderma Harzianum ◽  
Cell Walls ◽  
Agaricus Bisporus ◽  
Trichoderma Atroviride ◽  
Rapid Production ◽  
First Time ◽  
Group 1

ABSTRACT We examined the mycoparasitic and saprotrophic behavior of isolates representing groups of Trichoderma harzianum to establish a mechanism for the aggressiveness towards Agaricus bisporus in infested commercial compost. Mycoparasitic structures were infrequently observed in interaction zones on various media, including compost, with cryoscanning electron microscopy. T. harzianum grows prolifically in compost in the absence or presence of A. bisporus, and the aggressive European (Th2) and North American (Th4) isolates produced significantly higher biomasses (6.8- and 7.5-fold, respectively) in compost than did nonaggressive, group 1 isolates. All groups secreted depolymerases that could attack the cell walls of A. bisporus and of wheat straw, and some were linked to aggressiveness. Growth on mushroom cell walls in vitro resulted in rapid production of chymoelastase and trypsin-like proteases by only the Th2 and Th4 isolates. These isolates also produced a dominant protease isoform (pI 6.22) and additional chitinase isoforms. On wheat straw, Th4 produced distinct isoforms of cellulase and laminarinase, but there was no consistent association between levels or isoforms of depolymerases and aggressiveness. Th3's distinctive profiles confirmed its reclassification as Trichoderma atroviride. Proteases and glycanases were detected for the first time in sterilized compost colonized by T. harzianum. Xylanase dominated, and some isoforms were unique to compost, as were some laminarinases. We hypothesize that aggressiveness results from competition, antagonism, or parasitism but only as a component of, or following, extensive saprotrophic growth involving degradation of wheat straw cell walls.

scholarly journals The Alternative Activation Pathway and Complement Component C3 Are Critical for a Protective Immune Response against Pseudomonas aeruginosa in a Murine Model of Pneumonia

2004 ◽  
Vol 72 (5) ◽  
pp. 2899-2906 ◽  
Author(s):  
Stacey L. Mueller-Ortiz ◽  
Scott M. Drouin ◽  
Rick A. Wetsel
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Mortality Rate ◽  
Host Defense ◽  
Complement Activation ◽  
Alternative Pathway ◽  
Alternative Activation ◽  
Phagocytic Cells ◽  
Factor B ◽  
Activation Pathways

ABSTRACT Pseudomonas aeruginosa is a leading cause of hospital-acquired pneumonia, and approximately 80% of patients with cystic fibrosis are infected with this bacterium. To investigate the overall role of complement and the complement activation pathways in the host defense against P. aeruginosa pulmonary infection, we challenged C3-, C4-, and factor B-deficient mice with P. aeruginosa via intranasal inoculation. In these studies, C3−/− mice had a higher mortality rate than C3+/+ mice. Factor B−/− mice, but not C4−/− mice, infected with P. aeruginosa had a mortality rate similar to that of C3−/− mice, indicating that in this model the alternative pathway of complement activation is required for the host defense against Pseudomonas infection. C3−/− mice had 6- to 7-fold more bacteria in the lungs and 48-fold more bacteria in the blood than did C3+/+ mice at 24 h postinfection. In vitro, phagocytic cells from C3+/+ or C3−/− mice exhibited a decreased ability to bind and/or ingest P. aeruginosa in the presence of C3-deficient serum compared to phagocytic cells in the presence of serum with sufficient C3. C3−/− mice displayed a significant increase in neutrophils in the lungs and had higher levels of interleukin-1β (IL-1β), IL-6, IL-10, KC, and MIP-2 in the lungs at 24 h postinfection than did C3+/+ mice. Collectively, these results indicate that complement activation by the alternative pathway is critical for the survival of mice infected with P. aeruginosa and that the protection provided by complement is at least in part due to C3-mediated opsonization and phagocytosis of P. aeruginosa.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

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