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1.
Pathogen cells of Fusarium oxysporum f.sp. radicis-lycopersici infecting container-grown tomato plants were characterized ultrastructurally, using gold-complexed probes, chitinase and
wheat germ agglutinin to localize chitin, and polyclonal antibodies to a polygalacturonase to localize this enzyme. It was
isolated and purified from the pathogen growing in culture. Many fungal cells were of irregular forms (microhyphal, frondose)
with modified, thin or imperceptible lucent wall layers, in which were often included components seemingly of host origin.
Gold particles of the polygalacturonase probe were concentrated on portions of penetration hyphae and in areas of associated
altered host wall. Fine filamentous-like structures, often linked to fungal cells, reached into extracellular matter and into
host walls. Examination of 0.2–0.25 μm-thick sections at 120 kV, and tilted at various angles, indicated that fungal cells
frequently had a pronounced wavy contour. Labelling of thin walls for chitin was mostly nil, particularly in contact with
host walls, as of also thicker walls in similar situations, or it was then associated with the outside opaque layer. Cells
of diverse dimensions with thin or thicker walls and with altered or normal content, contained endocells. Walls of the encodcells
and of the enclosing cells often labelled differently for chitin with both probes. Endocells mostly did not originate from
proliferation of a living into a dead cell but often ensuing as an apparent fragmentation of the cell content or following
its retraction. The bearing of these observations on the host-pathogen relationship, particularly concerning the role of thin-walled
hyphae and irregular forms, is discussed. 相似文献
2.
The capacity of chitin (from crab shells) and of fungal cell walls from Trichoderma harzianum to accumulate zinc, cadmium and mercury was studied as well as the effects of adsorbed metals on the enzymatic hydrolysis by Novozym 234 of the two substrates. The total adsorbing capacity with respect to these metals was estimated to be at least 10 mmol kg–1 chitin (dry weight) and 50 mmol kg–1 fungal cell walls (dry weight), respectively, at pH 6.1. Enzymatic digestion of fungal cell walls preloaded with mercury and cadmium was significantly reduced, while zinc did not cause any significant inhibition. The effect of metal complexation by chitin on the enzymatic digestion was not as pronounced as for fungal cell walls. This could reflect the fact that chitin sorbed a lower total amount of metals. The inhibitory effect of metals on the enzymatic hydrolysis was caused by the association of the metals with the two substrates and not by the presence of free metals in solution. 相似文献
3.
The ability was determined of the rumen ciliate Eudiplodinium maggii to utilize chitin from fungal cell wall. Cultivation experiments shoved that the population concentration (number of ciliates
in vitro) was positively correlated with chitin doses. Cell extract prepared from the bacteria-free ciliates degraded colloidal chitin
releasing 2.0 μmol reducing sugar per mg protein per h. End products of this reaction were chitotriose and N-acetylglucosamine. Incubation of the bacteria-free ciliates with chitin resulted in an increase in the concentration of acetic,
propionic and butyric acids in the incubation medium. The production rate of total volatile fatty acids (VFA) by ciliates
incubated with and without chitin was 45.0 and 30.5 pmol VFA per protozoan, respectively, the molar proportion of particular
acids remaining unchanged. 相似文献
4.
Sedigheh Esmaeilzadeh Bahabadi Mozafar Sharifi Naser Safaie Jun Murata Tohru Yamagaki Honoo Satake 《Plant biotechnology reports》2011,5(4):367-373
Linum album accumulates anti-tumor podophyllotoxin (PTOX) and its related lignans, which were originally isolated from an endangered
species Podophyllum. In the present study, we examined the effects of five fungal extracts on the production of lignans in L. album cell cultures. Fusarium graminearum extract induced the highest increase of PTOX [143 μg g−1 dry weight (DW) of the L. album cell culture], while Rhizopus stolonifer extract enhanced the accumulation of lariciresinol up to 364 μg g−1 DW, instead of PTOX. Typical elicitors, such as chitin, chitosan, or methyl jasmonate (MeJA), were shown to be less effective
in lignan production in L. album cell cultures. These results verified the advantages of fungal extracts to increase lignan production in L. album cell culture, and suggested potential on-demand metabolic engineering of lignan biosynthesis using differential fungal extracts. 相似文献
5.
Fathia Aouidi Eltaeif Khelifi Nedra Asses Lamia Ayed Moktar Hamdi 《Journal of industrial microbiology & biotechnology》2010,37(8):877-882
Geotrichum candidum is a yeast-like filamentous fungus that has attracted industrial interest. The present work investigated G. candidum biomass production in agro-industrial wastewaters (olive mill wastewater (OMW) and cheese whey (CW)) as the only substrate.
Different solid media (Sabouraud dextrose agar (SDA), CW, OMW, and OMW/CW mixtures in different proportions) were tested.
OMW/CW mixtures proved to be suitable for optimal mycelia growth of G. candidum with a very high hyphae density. The highest fungal and expansion rate growth of 83 ± 1 mm and 12.4 day−1, respectively, were obtained on a 20:80 mixture of OMW/CW, which was incubated for 7 days. This optimal mixture was used
to study the biomass production and the OMW decolorization ability of G. candidum in the presence of CW in liquid medium. Liquid cultures were also conducted in OMW and CW separately. After 5 days of incubation,
fungal biomass reached 9.26 g l−1 in the OMW/CW mixture and only 2.83 g l−1 in CW, while no biomass production was observed in OMW alone. OMW decolorization and dephenolization by G. candidum also improved in the presence of CW with a decolorization efficiency of 54.5% and a total phenolic reduction of 55.3%, compared
with the control which yielded values of about 10% and 15%, respectively. These results suggested that OMW/CW—as the only
substrate—could be used as a cost-effective medium to produce G. candidum biomass, without the need for water dilution or supplementation with other nutriments. 相似文献
6.
Shigeyuki Tanaka Akari Ichikawa Kaori Yamada Gento Tsuji Takumi Nishiuchi Masashi Mori Hironori Koga Yoko Nishizawa Richard O'Connell Yasuyuki Kubo 《BMC plant biology》2010,10(1):288
Background
Rice CEBiP recognizes chitin oligosaccharides on the fungal cell surface or released into the plant apoplast, leading to the expression of plant disease resistance against fungal infection. However, it has not yet been reported whether CEBiP is actually required for restricting the growth of fungal pathogens. Here we evaluated the involvement of a putative chitin receptor gene in the basal resistance of barley to the ssd1 mutant of Magnaporthe oryzae, which induces multiple host defense responses. 相似文献7.
抑制真菌细胞壁的合成常作为防治真菌感染的安全有效手段。几丁质是真菌细胞壁及隔膜的重要结构成分,几丁质合酶是催化几丁质合成的关键酶。真菌细胞中几丁质合酶家族的不同成员在调控几丁质的合成中存在着差异,因此产生不同的生物学效应。本文通过综述几丁质合酶在人体三大条件致病真菌白色念珠菌、烟曲霉、新生隐球菌中的研究进展,分析了几丁质合酶对真菌致病性影响的机制,总结了几丁质合酶调控真菌细胞增殖、形态转换、病原菌与宿主的相互作用和细胞壁损伤诱导的补偿效应,展望了抗真菌感染的新策略及关于真菌几丁质合酶的未来研究方向。 相似文献
8.
Chitosan-mediated changes in cell wall composition, morphology and ultrastructure in two wood-inhabiting fungi 总被引:2,自引:0,他引:2
Damiano Vesentini Diane Steward Adya P. Singh Roderick Ball Geoffrey Daniel Robert Franich 《Mycological Research》2007,111(8):875-890
The effect of chitosan on cell wall deposition was investigated in the two wood-inhabiting fungal species Trichoderma harzianum (CBS 597.91) and Sphaeropsis sapinea (NZFS 2725). The study used three independent analytical techniques to quantify chitin in the fungal mycelium. A colorimetric method for the detection of d-glucosamine was compared with two gas chromatography–mass spectroscopy (GC-MS) methods employing alditol acetates analysis and pyrolysis. The latter used a stable-isotope-labelled internal standard, d3-N-acetyl glucosamine. At least in the case of S. sapinea, the study provided evidence of an increase in the chitin content in the mycelium due to chitosan treatment, indicating that chitosan treatment affected cell wall deposition. Electron microscopy techniques showed alteration in surface morphology and cell wall texture due to chitosan treatment. The implications of these results are discussed with a view to analysing possible mechanisms for growth inhibitory effects of chitosan on fungal hyphae. 相似文献
9.
Insect chitin synthases: a review 总被引:10,自引:0,他引:10
Merzendorfer H 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2006,176(1):1-15
Chitin is the most widespread amino polysaccharide in nature. The annual global amount of chitin is believed to be only one
order of magnitude less than that of cellulose. It is a linear polymer composed of N-acetylglucosamines that are joined in a reaction catalyzed by the membrane-integral enzyme chitin synthase, a member of the
family 2 of glycosyltransferases. The polymerization requires UDP–N-acetylglucosamines as a substrate and divalent cations as co-factors. Chitin formation can be divided into three distinct
steps. In the first step, the enzymes‘ catalytic domain facing the cytoplasmic site forms the polymer. The second step involves
the translocation of the nascent polymer across the membrane and its release into the extracellular space. The third step
completes the process as single polymers spontaneously assemble to form crystalline microfibrils. In subsequent reactions
the microfibrils combine with other sugars, proteins, glycoproteins and proteoglycans to form fungal septa and cell walls
as well as arthropod cuticles and peritrophic matrices, notably in crustaceans and insects. In spite of the good effort by
a hardy few, our present knowledge of the structure, topology and catalytic mechanism of chitin synthases is rather limited.
Gaps remain in understanding chitin synthase biosynthesis, enzyme trafficking, regulation of enzyme activity, translocation
of chitin chains across cell membranes, fibrillogenesis and the interaction of microfibrils with other components of the extracellular
matrix. However, cumulating genomic data on chitin synthase genes and new experimental approaches allow increasingly clearer
views of chitin synthase function and its regulation, and consequently chitin biosynthesis. In the present review, I will
summarize recent advances in elucidating the structure, regulation and function of insect chitin synthases as they relate
to what is known about fungal chitin synthases and other glycosyltransferases. 相似文献
10.
Rapid reactions comprising efflux of K+ and Cl−, phosphorylation of a 63-kDa protein (pp63), extracellular alkalinization and synthesis of H2O2 are equally induced in cells of Picea abies (L.) Karst. by chitotetraose, colloidal chitin and cell wall elicitors from the ectomycorrhizal fungus Hebeloma crustuliniforme (Bull. ex Fries.) Quél. an ectomycorrhizal partner of spruce. Cleavage of fungal cell wall elicitors and of artificial chitin
elicitors to monomeric and dimeric fragments by apoplasmic spruce chitinases (36-kDa class I chitinase, pI 8.0, and 28-kDa
chitinase, pI 8.7; EC 3.2.1.14) equally prevented induction of these rapid reactions. Also, N-acetylglucosamine oligomers
and elicitors from the fungal cell walls showed a similar dependence of their activity on the degree of polymerisation. From
these results it is suggested that, during ectomycorrhiza formation, only some of the chitin-derived elicitors reach their
receptors at the plant plasma membrane, initiating reactions of the hypersensitive response in the host cells. The remaining
fungal elicitors will be degraded to varying extents by wall-localized chitinases of the host root, reducing the defence reactions
of the plant and allowing symbiotic interactions of both organisms.
Received: 6 January 1997 / Accepted: 14 March 1997 相似文献
11.
Xin Li Chun-Shan Quan Hui-Ying Yu Jian-Hua Wang Sheng-Di Fan 《World journal of microbiology & biotechnology》2009,25(1):151-154
A novel compound CF66I produced by Burkholeria cepacia was investigated for its antifungal effects against Fusarium solani by three different fluorescent dyes. Dual staining with propidium iodide (PI) and fluorescein diacetate (FDA) demonstrated
high doses of CF66I (120.0 μg ml−1) killed the fungi by acting primarily on the cell membrane. However, at fungistatic concentration (20.0 μg ml−1) of this compound, microscopic observations revealed swelling hyphae with abnormal chitin deposition, as determined by Calcofluor
white (CFW) staining, which was indicative of the alterations in cell wall structure. In addition, inhibition of intracellular
esterases activity was observed. These results led us to conclude that low doses of CF66I probably inhibited the fungal growth
by interfering with the cell metabolic pathways. 相似文献
12.
Compression wood (CW) contains higher quantities of β-1-4-galactan than does normal wood (NW). However, the physiological
roles and ultrastructural distribution of β-1-4-galactan during CW formation are still not well understood. The present work
investigated deposition of β-1-4-galactan in differentiating tracheids of Cryptomeria japonica during CW formation using an immunological probe (LM5) combined with immunomicroscopy. Our immunolabeling studies clearly
showed that differences in the distribution of β-1-4-galactan between NW (and opposite wood, OW) and CW are initiated during
the formation of the S1 layer. At this stage, CW was strongly labeled in the S1 layer, whereas no label was observed in the S1 layer of NW and OW. Immunogold labeling showed that β-1-4-galactan in the S1 layer of CW tracheids significantly decreased during the formation of the S2 layer. Most β-1-4-galactan labeling was present in the outer S2 region in mature CW tracheids, and was absent in the inner S2 layer that contained helical cavities in the cell wall. In addition, delignified CW tracheids showed significantly more labeling
of β-1-4-galactan in the secondary cell wall, suggesting that lignin is likely to mask β-1-4-galactan epitopes. The study
clearly showed that β-1-4-galactan in CW was mainly deposited in the outer portion of the secondary cell wall, indicating
that its distribution may be spatially consistent with lignin distribution in CW tracheids of Cryptomeria japonica. 相似文献
13.
Background
Chitinases (EC.3.2.1.14) hydrolyze the β-1,4-linkages in chitin, an abundant N-acetyl-β-D-glucosamine polysaccharide that is a structural component of protective biological matrices such as insect exoskeletons and fungal cell walls. The glycoside hydrolase 18 (GH18) family of chitinases is an ancient gene family widely expressed in archea, prokaryotes and eukaryotes. Mammals are not known to synthesize chitin or metabolize it as a nutrient, yet the human genome encodes eight GH18 family members. Some GH18 proteins lack an essential catalytic glutamic acid and are likely to act as lectins rather than as enzymes. This study used comparative genomic analysis to address the evolutionary history of the GH18 multiprotein family, from early eukaryotes to mammals, in an effort to understand the forces that shaped the human genome content of chitinase related proteins. 相似文献14.
Nicole Benhamou Alain Asselin 《Biology of the cell / under the auspices of the European Cell Biology Organization》1989,67(3):341-350
Ultrathin sections of healthy and fungus-infected plant tissue were treated with either wheat-germ agglutinin (WGA) ovomucoid-gold complex or microbial chitinase-gold complexes for localizing putative chitin-like macromolecules. Fungal cell walls, known to contain chitin, were labeled with both probes and were considered as positive controls. Plant secondary cell walls of both healthy and infected tissues were also intensely labeled whereas compound middle lamella-primary walls and cell cytoplasm were free of labeling. Enzymatic digestion of plant tissues with chitinase from Streptomyces griseus abolished the fungal cell wall labeling but did not interfere with that of plant secondary cell walls. This suggests that polymers analogous to fungal chitin are absent in plant cell walls. Tissue digestions with either proteinase K or lipase led to surprising results as far as the possible nature of N-acetylglucosamine-containing molecules is concerned. The loss of labeling over plant secondary walls following lipase digestion suggests that N-acetylglucosamine residues may be linked to lipids to form glycolipids. However, these results have to be viewed with caution since the possibility that peptides may be present but inacessible to proteinase K should be considered. The role of the detected N-acetylglucosamine containing molecules as possible substrates for plant chitinases is discussed. 相似文献
15.
Jacqueline Capataz-Tafur Gabriela Trejo-Tapia Mario Rodríguez-Monroy Gabriela Sepúlveda-Jiménez 《Plant Cell, Tissue and Organ Culture》2011,106(1):169-177
Arabinogalactan proteins (AGPs) are glycoproteins present at cell surfaces. Although exact functions of AGPs remain elusive,
they are implicated in plant growth and development. The aim of this study was to evaluate the role of AGPs in the process
of cell aggregation of Beta vulgaris L. suspension cultures. It was observed that B. vulgaris suspension cultures accumulated AGPs in parallel form to its cell growth. The AGPs maximum content in the stationary phase
was 0.330 mg g−1 dry weight (DW) in the cell wall (CW) and 1.534 mg g−1 DW in the culture medium (CM), generating cell aggregates >500 μm (93.21% DW). The addition of tunicamycin (TM) caused a
reduction of AGPs content in CW and CM of 46 and 64%, respectively. These changes were associated with inhibition of growth
and the reduction of the cell aggregates >500 μm (50.0% DW). When TM was removed from the CM, cell growth, aggregation, and
AGPs content on CW and CM were recovered. Precipitation of AGPs with Yariv reagent generated a reduction of 61.14% of AGPs
content in CW and a total inhibition of AGPs secretion in CM. This Yariv treatment generated a reduction in the cell aggregates
>500 μm of 51.31% of DW. When the Yariv reagent was removed from the culture, cells did not recover their AGPs accumulation.
In addition, cell cultures did not recover their ability to grow and aggregate. These results indicate that AGPs are molecules
required in the cellular aggregation process of B. vulgaris L. suspension cultures. 相似文献
16.
Masaru Sakurada Diego P. Morgavi Kenji Komatani Yoshifumi Tomita Ryoji Onodera 《Current microbiology》1997,35(1):48-51
An autolysis chitinase was purified from the cultural medium of the anaerobic fungus Piromyces communis OTS1 by ammonium sulfate precipitation, affinity chromatography with regenerated chitin, chromato-focusing, gel filtration,
and chromato-focusing again. The optimal pH and temperature were 6.0 and 50°C, respectively, for a 20-min assay. The chitinase
was stable from pH 6.0 to 8.0, but was unstable at 70°C for 20 min. The molecular mass of chitinase was estimated by SDS-PAGE
to be 44.9 kDa, and its pI was 4.4. The enzyme activity, which was of the ‘endo’ type, was inhibited by Hg2+ and allosamidin. The chitinase hydrolyzes chitin powder and fungal cell walls at a higher rate than an artificial chitin
substrate. It can be concluded that extracellular chitinase is similar to cytosolic chitinase, but they are not the same protein.
Received: 3 December 1996 / Accepted: 28 January 1997 相似文献
17.
Kalebina TS Farkas V Laurinavichiute DK Gorlovoy PM Fominov GV Bartek P Kulaev IS 《Antonie van Leeuwenhoek》2003,84(3):179-184
It is shown that the deletion of BGL2 gene leads to increase in chitin content in the cell wall of Saccharomyces cerevisiae. A part of the additional chitin can be removed from the bgl2Δ cell wall by alkali or trypsin treatment. Chitin synthase 1 (Chs1) activity was increased by 60 % in bgl2Δ mutant. No increase in chitin synthase 3 (Chs3) activity in bgl2Δ cells was observed, while they became more sensitive to Nikkomycin Z. The chitin level in the cell walls of a strain lacking
both BGL2 and CHS3 genes was higher than that in chs3Δ and lower than that in bgl2Δ strains. Together these data indicate that the deletion of BGL2 results in the accumulation and abnormal incorporation of chitin into the cell wall of S. cerevisiae, and both Chs1 and Chs3 take part in a response to BGL2 deletion in S. cerevisiae cells.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
18.
Ali Dehestani Kamal Kazemitabar Gholamreza Ahmadian Nadali Babaeian Jelodar Ali Hatef Salmanian Mehdi Seyedi Heshmat Rahimian Seyedhadi Ghasemi 《Biotechnology letters》2010,32(4):539-546
The Bacillus pumilus SG2 chitinase gene (ChiS) and its truncated form lacking chitin binding (ChBD) and fibronectin type III (FnIII) domains were transformed to Arabidopsis plants and the expression, functionality and antifungal activity of the recombinant proteins were investigated. Results showed
that while the two enzyme forms showed almost equal hydrolytic activity toward colloidal chitin, they exhibited a significant
difference in antifungal activity. Recombinant ChiS in plant protein extracts displayed a high inhibitory effect on spore
germination and radial growth of hyphae in Alternaria brassicicola, Fusarium graminearum and Botrytis cinerea, while the activity of the truncated enzyme was strongly abolished. These findings demonstrate that ChBD and FnIII domains
are not necessary for hydrolysis of colloidal chitin but play an important role in hydrolysis of chitin–glucan complex of
fungal cell walls. Twenty microgram aliquots of protein extracts from ChiS transgenic lines displayed strong antifungal activity
causing up to 80% decrease in fungal spore germination. This is the first report of a Bacillus pumilus chitinase expressed in plant system. 相似文献
19.
Laetitia Muszkieta Vishukumar Aimanianda Emilia Mellado Simonetta Gribaldo Laura Alcàzar‐Fuoli Edyta Szewczyk Marie‐Christine Prevost Jean‐Paul Latgé 《Cellular microbiology》2014,16(12):1784-1805
Although chitin is an essential component of the fungal cell wall (CW), its biosynthesis and role in virulence is poorly understood. In Aspergillus fumigatus, there are eight chitin synthase (CHS) genes belonging to two families CHSA‐C, CHSG in family 1 and CHSF, CHSD, CSMA, CSMB in family 2). To understand the function of these CHS genes, their single and multiple deletions were performed using β‐rec/six system to be able to delete all genes within each family (up to a quadruple ΔchsA/C/B/G mutant in family 1 and a quadruple ΔcsmA/csmB/F/D mutant in family 2). Radial growth, conidiation, mycelial/conidial morphology, CW polysaccharide content, Chs‐activity, susceptibility to antifungal molecules and pathogenicity in experimental animal aspergillosis were analysed for all the mutants. Among the family 1 CHS, ΔchsA, ΔchsB and ΔchsC mutants showed limited impact on chitin synthesis. In contrast, there was reduced conidiation, altered mycelial morphotype and reduced growth and Chs‐activity in the ΔchsG and ΔchsA/C/B/G mutants. In spite of this altered phenotype, these two mutants were as virulent as the parental strain in the experimental aspergillosis models. Among family 2 CHS, phenotypic defects mainly resulted from the CSMA deletion. Despite significant morphological mycelial and conidial growth phenotypes in the quadruple ΔcsmA/csmB/F/D mutant, the chitin content was poorly affected by gene deletions in this family. However, the entire mycelial cell wall structure was disorganized in the family 2 mutants that may be related to the reduced pathogenicity of the quadruple ΔcsmA/csmB/F/D mutant strain compared to the parental strain, in vivo. Deletion of the genes encompassing the two families (ΔcsmA/csmB/F/G) showed that in spite of being originated from an ancient divergence of fungi, these two families work cooperatively to synthesize chitin in A. fumigatus and demonstrate the essentiality of chitin biosynthesis for vegetative growth, resistance to antifungal drugs, and virulence of this filamentous fungus. 相似文献
20.
Siddhartha G. V. A. O. Costa François Lépine Sylvain Milot Eric Déziel Marcia Nitschke Jonas Contiero 《Journal of industrial microbiology & biotechnology》2009,36(8):1063-1072
Glycerol, cassava wastewater (CW), waste cooking oil and CW with waste frying oils were evaluated as alternative low-cost
carbon substrates for the production of rhamnolipids and polyhydroxyalkanoates (PHAs) by various Pseudomonas aeruginosa strains. The polymers and surfactants produced were characterized by gas chromatography–mass spectrophotometry (MS) and by
high-performance liquid chromatography–MS, and their composition was found to vary with the carbon source and the strain used
in the fermentation. The best overall production of rhamnolipids and PHAs was obtained with CW with frying oil as the carbon
source, with PHA production corresponding to 39% of the cell dry weight and rhamnolipid production being 660 mg l−1. Under these conditions, the surface tension of the culture decreased to 30 mN m−1, and the critical micelle concentration was 26.5 mg l−1. It would appear that CW with frying oil has the highest potential as an alternative substrate, and its use may contribute
to a reduction in the overall environmental impact generated by discarding such residues. 相似文献