Le Stigmidium lecidellae sp.nov. et remarques sur le genre Stigmidium (champignons lichénicoles non lichénisés, Ascomycètes)

1995 ◽  
Vol 73 (4) ◽  
pp. 662-672 ◽  
Author(s):  
Claude Roux ◽  
Olivier Bricaud ◽  
Didier Le Coeur ◽  
Dagmar Triebel
Keyword(s):  
Cell Wall ◽  
Key Words ◽  
Cell Walls ◽  
Species Level ◽  
Lichenicolous Fungi ◽  
Cresyl Blue ◽  
Taxonomic Key

Stigmidium lecidellae Triebel, Roux et Le Coeur sp.nov., a mild pathogenic lichenicolous fungus growing on the apothecia of Lecidella elaeochroma (Ach.) M. Choisy is described in detail and compared with other species of Stigmidium that grow on the apothecia of the host. The staining of parts of cell walls with cresyl blue is constant at species level and, therefore, is taxonomically relevant in the genus Stigmidium. The dye also allows to distinguish some ultrastructural details of the vegetative hyphal cells, asci, and ascospores. Among the fungi species growing on the apothecia of lichens, three groups are distinguished on the basis of their hamathecial structure, one of which should be excluded from the genus Stigmidium and included in the genus Sphaerellothecium. A key to the determination of the species is presented. Key words: lichenicolous fungi, Stigmidium, Sphaerellothecium, taxonomy, taxonomic key, cell wall, staining reactions, hamathecium.

Microtubular configurations during endosperm development in Phaseolus vulgaris

1994 ◽  
Vol 72 (10) ◽  
pp. 1489-1495 ◽  
Author(s):  
X. XuHan ◽  
A. A. M. Van Lammeren
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Phaseolus Vulgaris ◽  
Key Words ◽  
Cell Walls ◽  
Endosperm Development ◽  
Initial Cell ◽  
Related Cell ◽  
Cellular Endosperm ◽  
Cell Shaping

Microtubular cytoskeletons in nuclear, alveolar, and cellular endosperm of bean (Phaseolus vulgaris) were analyzed immunocytochemically and by electron microscopy to reveal their function during cellularization. Nuclear endosperm showed a fine network of microtubules between the wide-spaced nuclei observed towards the chalazal pole. Near the embryo, where nuclei were densely packed, bundles of microtubules radiated from nuclei. They were formed just before alveolus formation and functioned in spacing nuclei and in forming internuclear, phragmoplast-like structures that gave rise to nonmitosis-related cell plates. During alveolus formation cell plates extended and fused with other newly formed walls, thus forming the walls of alveoli. Growing wall edges of cell plates exhibited arrays of microtubules perpendicular to the plane of the wall, initially. When two growing walls were about to fuse, microtubules of both walls interacted, and because of the interaction of microtubules, the cell walls changed their position. When a growing wall was about to fuse with an already existing wall, such interactions between microtubules were not observed. It is therefore concluded that interactions of microtubules of fusing walls influence shape and position of walls. Thus microtubules control the dynamics of cell wall positioning and initial cell shaping. Key words: cell wall, cellularization, endosperm, microtubule, Phaseolus vulgaris.

Determination of transport constants of isolated Nitella cell walls

1968 ◽  
Vol 46 (4) ◽  
pp. 317-327 ◽  
Author(s):  
M. T. Tyree
Keyword(s):  
Activation Energy ◽  
Cell Wall ◽  
Diffusion Coefficient ◽  
Cell Walls ◽  
Transport Coefficients ◽  
Irreversible Thermodynamics ◽  
Kcal Mole ◽  
Limiting Value ◽  
Nitella Flexilis

Transport coefficients LPP, LPE, LEP, and LEE for electrokinetic equations according to irreversible thermodynamics, the Onsager coefficients, were measured for isolated Nitella flexilis cell walls in KCl solutions ranging from 10−4 to 100 normal. LPP and LPE (= LEP) were found to be independent of KCl concentration and equal to 1.4 × 10−6 cm3 sec−1 cm−2 (joule cm−3)−1 cm and 6 × 10−5 cm3 sec−1 cm−2 volt−1 cm respectively. LEE was a function of the salt concentration, reaching a limiting value of about 1.2 × 10−3 mho cm−1 in 10−4 N KCl. The activation energy for movement of KCl in cell walls was found to be 4.33 Kcal mole−1; the diffusion coefficient for KCl in cell walls was calculated by two methods to be 8 × 10−6 cm2 sec−1; and the concentration of the fixed ions in Nitella cell walls from the above data was estimated at greater than 0.04 equivalent per liter of cell wall. Electroosmosis in Nitella membranes is re-examined in the light of the measured transport coefficients and it is concluded that under proper conditions the cell wall of Nitella can contribute significantly (~20% or more) to the observed electroosmosis of living Nitella cells.

Chemical analysis of isolated cell walls of Gram-positive bacteria and determination of the cell wall to cell mass ratio

1997 ◽  
Vol 28 (2) ◽  
pp. 147-157 ◽  
Author(s):  
Albert van der Wal ◽  
Willem Norde ◽  
Bernd Bendinger ◽  
Alexander J.B Zehnder ◽  
Johannes Lyklema
Keyword(s):  
Cell Wall ◽  
Chemical Analysis ◽  
Cell Walls ◽  
Cell Mass ◽  
Mass Ratio ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Isolated Cell

scholarly journals Two Novel Techniques for Determination of Polysaccharide Cross-Links Show that Crh1p and Crh2p Attach Chitin to both β(1-6)- and β(1-3)Glucan in the Saccharomyces cerevisiae Cell Wall

2009 ◽  
Vol 8 (11) ◽  
pp. 1626-1636 ◽  
Author(s):  
Enrico Cabib
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Acetic Acid ◽  
Yeast Cell ◽  
Cell Walls ◽  
Double Mutant ◽  
The Other ◽  
Cross Links

ABSTRACT Previous work, using solubilization of yeast cell walls by carboxymethylation, before or after digestion with β(1-3)- or β(1-6)glucanase, followed by size chromatography, showed that the transglycosylases Crh1p and Crh2p/Utr2p were redundantly required for the attachment of chitin to β(1-6)glucan. With this technique, crh1Δ crh2Δ mutants still appeared to contain a substantial percentage of chitin linked to β(1-3)glucan. Two novel procedures have now been developed for the analysis of polysaccharide cross-links in the cell wall. One is based on the affinity of curdlan, a β(1-3)glucan, for β(1-3)glucan chains in carboxymethylated cell walls. The other consists of in situ deacetylation of cell wall chitin, generating chitosan, which can be extracted with acetic acid, either directly (free chitosan) or after digestion with different glucanases (bound chitosan). Both methodologies indicated that all of the chitin in crh1Δ crh2Δ strains is free. Reexamination of the previously used procedure revealed that the β(1-3)glucanase preparation used (zymolyase) is contaminated with a small amount of endochitinase, which caused erroneous results with the double mutant. After removing the chitinase from the zymolyase, all three procedures gave coincident results. Therefore, Crh1p and Crh2p catalyze the transfer of chitin to both β(1-3)- and β(1-6)glucan, and the biosynthetic mechanism for all chitin cross-links in the cell wall has been established.

scholarly journals UDP-GLYCOSYLTRANSFERASE 72E3 Plays a Role in Lignification of Secondary Cell Walls in Arabidopsis

2020 ◽  
Vol 21 (17) ◽  
pp. 6094
Author(s):  
Fabien Baldacci-Cresp ◽  
Julien Le Roy ◽  
Brigitte Huss ◽  
Cédric Lion ◽  
Anne Créach ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Lignin Content ◽  
Mutant Cell ◽  
Subsequent Investigation ◽  
Secondary Cell Walls ◽  
Chemical Determination ◽  
Safranin O

Lignin is present in plant secondary cell walls and is among the most abundant biological polymers on Earth. In this work we investigated the potential role of the UGT72E gene family in regulating lignification in Arabidopsis. Chemical determination of floral stem lignin contents in ugt72e1, ugt72e2, and ugt72e3 mutants revealed no significant differences compared to WT plants. In contrast, the use of a novel safranin O ratiometric imaging technique indicated a significant increase in the cell wall lignin content of both interfascicular fibers and xylem from young regions of ugt72e3 mutant floral stems. These results were globally confirmed in interfascicular fibers by Raman microspectroscopy. Subsequent investigation using a bioorthogonal triple labelling strategy suggested that the augmentation in lignification was associated with an increased capacity of mutant cell walls to incorporate H-, G-, and S-monolignol reporters. Expression analysis showed that this increase was associated with an up-regulation of LAC17 and PRX71, which play a key role in lignin polymerization. Altogether, these results suggest that UGT72E3 can influence the kinetics of lignin deposition by regulating monolignol flow to the cell wall as well as the potential of this compartment to incorporate monomers into the growing lignin polymer.

scholarly journals Determination of Subunit Composition of Clostridium cellulovorans Cellulosomes That Degrade Plant Cell Walls

2002 ◽  
Vol 68 (4) ◽  
pp. 1610-1615 ◽  
Author(s):  
Koichiro Murashima ◽  
Akihiko Kosugi ◽  
Roy H. Doi
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Scaffolding Protein ◽  
Plant Cell Walls ◽  
Higher Plant ◽  
Clostridium Cellulovorans ◽  
Plant Cell Wall Degradation

ABSTRACT Clostridium cellulovorans produces a cellulase enzyme complex (cellulosome). In this study, we isolated two plant cell wall-degrading cellulosomal fractions from culture supernatant of C. cellulovorans and determined their subunit compositions and enzymatic activities. One of the cellulosomal fractions showed fourfold-higher plant cell wall-degrading activity than the other. Both cellulosomal fractions contained the same nine subunits (the scaffolding protein CbpA, endoglucanases EngE and EngK, cellobiohydrolase ExgS, xylanase XynA, mannanase ManA, and three unknown proteins), although the relative amounts of the subunits differed. Since only cellobiose was released from plant cell walls by the cellulosomal fractions, cellobiohydrolases were considered to be key enzymes for plant cell wall degradation.

scholarly journals Cell walls as taxonomic markers in Polish species of the genus Odontoschisma (Dum.) Dum. (Hepaticae, Cephaloziaceae)

2014 ◽  
Vol 68 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Jerzy Szweykowski ◽  
Katarzyna Buczkowska
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Polarized Light ◽  
Ruthenium Red ◽  
European Species ◽  
Diagnostic Characters ◽  
Cell Lumen ◽  
Taxonomic Markers ◽  
Stem Structure

To get valuable diagnostic characters, the structure of cell walls was studied with use of two stains (Ruthenium Red -RR and Resorcine Blue - RB) and in polarized light. As far as the stem structure is concerned, European species of the genus <em>Odontoschisma</em> fall into two groups: in <em>Odontoschisma elongatum</em> and in <em>Odontoschisma macounii</em> a thick, frequently completely obscuring cell lumen, "lining layer" is present. It frequently, particularly after staining in RB, detaches from the rest of the cell wall. Such a layer is completely lacking in the two remaining species, viz. <em>O. sphagni</em> and <em>0. denudatum</em>. In polarized light only leaves of <em>O. sphagni</em> show a distinct bright border. The thin cellulose layer (bright in polarized light) embrace the angular thickenings in <em>0. sphagni</em> and <em>0. denudatum</em>, but is entering the inside of these thickenings in the two remaining species. Keys for determination of the four European species based on the staining properties of cell walls and their look in polarized light are provided.

The chemical ecology of lichen mycoparasites: a review

1995 ◽  
Vol 73 (S1) ◽  
pp. 603-608 ◽  
Author(s):  
James D. Lawrey
Keyword(s):  
Cell Wall ◽  
Secondary Metabolites ◽  
Key Words ◽  
Chemical Ecology ◽  
Laboratory Studies ◽  
Cell Wall Degrading Enzymes ◽  
Host Preferences ◽  
Defense Compounds ◽  
Lichenicolous Fungi ◽  
Unique Mode

Lichenicolous fungi colonize lichens to form a variety of biotrophic associations, and while some 300 genera and 1000 species have been recognized, almost nothing is known about their biology. The lichenicolous habit is an unusual one because lichens produce a variety of antibiotic secondary metabolites that are assumed to protect them from parasitic attack. This may explain why lichens are rarely parasitized in nature while nonlichen-forming Ascomycetes are frequently and extensively parasitized. Recent field and laboratory studies of lichen parasites from a number of fungal groups indicate that chemistry is indeed involved in these interactions. These results indicate that (i) lichenicolous taxa are better able to degrade lichens than related nonlichenicolous taxa, (ii) lichen parasites are generally tolerant of lichen secondary metabolites, (iii) this tolerance seems to be based in part on the ability of cell wall degrading enzymes of parasites to remain active in the presence of these lichen secondary metabolites, and (iv) the host preferences of some lichen parasites reflect these tolerances. Therefore, it appears likely that lichenicolous fungi, which have presumably had lengthy coevolutionary histories with lichens, have evolved a unique mode of nutrition that is based in part on an ability to tolerate lichen defense compounds. Key words: Hobsonia, lichens, lichenicolous fungi, Nectria, parasites.

scholarly journals Superoxide Generation in Extracts from Isolated Plant Cell Walls Is Regulated by Fungal Signal Molecules

1997 ◽  
Vol 87 (8) ◽  
pp. 846-852 ◽  
Author(s):  
Akinori Kiba ◽  
Chizu Miyake ◽  
Kazuhiro Toyoda ◽  
Yuki Ichinose ◽  
Tetsuji Yamada ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Cell Walls ◽  
Mycosphaerella Pinodes ◽  
Signal Molecules ◽  
Plant Cell Walls ◽  
Manganese Ion ◽  
Species Specific ◽  
Plant Fungal Pathogen

Fractions solubilized with NaCl from cell walls of pea and cowpea plants catalyzed the formation of blue formazan from nitroblue tetrazolium. Because superoxide dismutase decreased formazan production by over 90%, superoxide anion (O2¯) may participate in the formation of formazan in the solubilized cell wall fractions. The formazan formation in the fractions solubilized from pea and cowpea cell walls was markedly reduced by exclusion of NAD(P)H, manganese ion, or p-coumaric acid from the reaction mixture. The formazan formation was severely inhibited by salicylhydroxamic acid and catalase, but not by imidazole, pyridine, quinacrine, and diphenyleneiodonium. An elicitor preparation from the pea pathogen Mycosphaerella pinodes enhanced the activities of formazan formation nonspecifically in both pea and cowpea fractions. The suppressor preparation from M. pinodes inhibited the activity in the pea fraction in the presence or absence of the elicitor. In the cowpea fraction, however, the suppressor did not inhibit the elicitor-enhanced activity, and the suppressor alone stimulated formazan formation. These results indicated that O2¯ generation in the fractions solubilized from pea and cowpea cell walls seems to be catalyzed by cell wall-bound peroxidase(s) and that the plant cell walls alone are able to respond to the elicitor non-specifically and to the suppressor in a species-specific manner, suggesting the plant cell walls may play an important role in determination of plant-fungal pathogen specificity.

HIGH-ROUGHAGE RATIONS WITH OR WITHOUT MONENSIN FOR VEAL PRODUCTION. II. RATION DIGESTIBILITY

1989 ◽  
Vol 69 (2) ◽  
pp. 403-410 ◽  
Author(s):  
C. POMAR ◽  
J. F. BERNIER ◽  
J. R. SEOANE ◽  
L. LATRILLE
Keyword(s):  
Cell Wall ◽  
Key Words ◽  
Cell Walls ◽  
Crude Protein ◽  
Dry Matter ◽  
Animal Species ◽  
Acid Detergent Fiber ◽  
Ad Libitum

Thirty-six calves 19–20 wk old (149 ± 17 kg) and forty-eight rams (46 ± 4 kg) were used in two experiments to study the effects of two ground roughages (alfalfa and timothy), their proportion in pelleted rations (20, 40 and 60%) and addition of monensin (0 and 33 ppm) on ration digestibility. Calves and rams were fed the test rations ad libitum for a period of 8 and 5 wk, respectively, before the digestibility trial. Dry matter (DM) digestibility in both species and energy digestibility in calves were significantly higher for the rations containing alfalfa than for those containing timothy; however, digestibility of crude protein (CP) in both animal species and of cell walls (NDF) in calves was lower in alfalfa rations. The two trials revealed an increase in digestibility of acid detergent fiber (ADF) and of cell wall (NDF) fractions but a reduction in DM digestibility when the roughage content in the rations increased; the reduction in DM digestibility was larger with timothy than with alfalfa. Addition of monensin did not affect digestion coefficients of DM, ADF and NDF in calves and rams on average. However, a monensin × roughage level interaction indicated a decrease of ADF and NDF digestibility in calves fed 20% roughage and an increase of ADF and NDF digestibility in calves fed 60% roughage. Key words: Alfalfa, timothy roughage level, monensin, calf, sheep

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