119 research outputs found
Phenotypic and molecular characterization of Chaetopyrena penicillata from Iran with description of a hyphomycete synanomorph
During a survey of fungi associated with Russian olive fruit rot in Northern Iran, a coelomycete fungus with setose pycnidia was isolated from symptomatic fruits. The fungus was identified as Chaetopyrena penicillata based on morphological characteristics and sequence data of ITS and LSU rDNA. A hyphomycete synanamorph, which was observed in pure cultures of this species for the first time, is described. The morphology and phylogeny of Chaetopyrena penicillata is discussed
Rapid and Easy Modified Plate-based Screening Methods for Quantitative and Qualitative Detection of Protease Production by Fungi
Proteases constitute a significant part of cell wall-degrading enzymes (CWDEs)
produced by fungal biocontrol agents and particularly crucial in mycoparasitism
of fungal phytopathogens. Plate-based screening methods are routinely used for
screening protease-producing microorganisms including fungi. Skim milk agar
(SMA) is one of the most popular media for the detection of protease producing
bacteria. However, SMA is not efficient to test fast growing fungi, because it
does not give an estimation of the actual amount of secreted protease produced
by fungal inocula. In the current study, the efficacy of two modified
plate-screening methods, including split-SMA (SSMA) and minimal medium
supplemented with skim milk (MSMW) was assessed for detection of protease
production by three representative fungal strains including Trichoderma
longibrachiatum strain N, Beauveria bassiana
strain B and Purpureocillium lilacinum strain PL. Protease
production was revealed on the three tested media by the three strains. However,
the halo diameter of the fungal strains (a proxy for protease production) was
the smallest on SMA. Furthermore, protease production could not be detected for
T. longibrachiatum strain N on SMA due to its fast growth;
while it showed the highest protease activity on both modified media compared
with the other strains. According to the result of this study, the SSMA medium
is an easy and more accurate method compared with the two other different
methods as it displays the actual amount of protease produced by fungal strains
and therefore this method is recommended for quantitative and qualitative
detection of protease production by slow and fast growing fungi
Molecular Diagnostics in the Mycosphaerella Leaf Spot Disease Complex of Banana and for Radopholus similis
Mycosphaerella leaf spots and nematodes threaten banana cultivation worldwide. The Mycosphaerella disease complex involves three related ascomycetous fungi: Mycosphaerella fijiensis, M. musicola and M. eumusae. The exact distribution of these three species and their disease epidemiology remain unclear, since their symptoms and life cycles are rather similar. Diagnosing these diseases and the respective causal agents is based on the presence of host symptoms and fungal fruiting structures, but is time consuming and not conducive to preventive management. In the present study, we developed rapid and robust species-specific diagnostic tools to detect and quantify M. fijiensis, M. musicola and M. eumusae. Conventional species-specific PCR primers were developed based on the actin gene that detected as little as 100, 1 and 10 pg/µl DNA from, respectively, M. fijiensis, M. musicola and M. eumusae. Furthermore, TaqMan real-time quantitative PCR assays that were developed based on the ß-tubulin gene detected quantities as low as 1 pg/µl DNA of each species from pure cultures and 1.6 pg/µl DNA/mg of M. fijiensis from dry leaf tissue. The efficacy of the tests was validated using naturally infected banana leaves. Similar technology has been used to develop a quantitative PCR assay for the banana burrowing nematode, Radopholus similis, which is currently being validate
Two novel <i>Aspergillus </i>species from hypersaline soils of The National Park of Lake Urmia, Iran
Two novel Aspergillus species, one belonging to the section Terrei and the other to section Flavipedes, were isolated from hypersaline soils of The National Park of Lake Urmia (Iran) and are here described as Aspergillus iranicus and Aspergillus urmiensis. A polyphasic taxonomic approach comprising extrolite profiles, phenotypic characters and molecular data (beta-tubulin, calmodulin and ribosomal polymerase II second largest subunit gene sequences) was applied to determine their novel taxonomic status. Aspergillus iranicus (CBS 139561T) is phylogenetically related to A. carneus, A. niveus, A. allahabadii and A. neoindicus, and it can be differentiated from those species by a unique extrolite pattern (citrinin, gregatins, and a terrequinone) and its conidial colour. Aspergillus urmiensis (CBS 139558T) shares a most recent common ancestor with A. templicola. The former species produces globose vesicles, and those of A. templicola are predominantly elongate. The Aspergillus urmiensis isolates produce several uncharacterized extrolites. Two other strains obtained during this study reside in a clade, together with the type strain of A. movilensis (CCF 4410T), and are identified accordingly. Based on the phylogenetic data presented in this study, A. frequens is reduced to synonymy with A. micronesiensis and A. mangaliensis is considered to be a synonym of A. templicola
Allicin from garlic inhibits the biofilm formation and urease activity of Proteus mirabilis in vitro
Several virulence factors contribute to the pathogenesis of Proteus mirabilis. This study determined the inhibitory effects of allicin on urease, hemolysin and biofilm of P. mirabilis ATCC 12453 and its antimicrobial activity against 20 clinical isolates of P. mirabilis. Allicin did not inhibit hemolysin, whereas it did inhibit relative urease activity in both pre-lysed (half-maximum inhibitory concentration, IC50 = 4.15 μg) and intact cells (IC50 = 21 μg) in a concentration-dependent manner. Allicin at sub-minimum inhibitory concentrations (2-32 μg mL-1) showed no significant effects on the growth of the bacteria (P>0.05), but it reduced biofilm development in a concentration-dependent manner (P<0.001).A higher concentration of allicin was needed to inhibit the established biofilms. Using the microdilution technique, the MIC90 and MBC90 values of allicin against P. mirabilis isolates were determined to be 128 and 512 μg mL-1, respectively.The results suggest that allicin could have clinical applications in controlling P. mirabilis infections. © FEMS 2015. All rights reserved
Faecal carriage of high-level aminoglycoside-resistant and ampicillin-resistant Enterococcus species in healthy Iranian children
Objectives: High-level aminoglycoside, ampicillin and vancomycin resistance and virulence genes among enterococcal isolates collected from healthy middle-school children in Ardabil, Iran, during 2016 were investigated. Methods: Totally, 305 faecal specimens were collected. Isolates underwent antimicrobial susceptibility testing, virulence gene detection and molecular typing. Results: Totally, 409 enterococcal isolates were collected, comprising Enterococcus faecium (235; 57.5), Enterococcus faecalis (56; 13.7) and other Enterococcus spp. (118; 28.9). Overall, 71 (17.4), 11 (2.7) and 10 (2.4) isolates were identified as high-level streptomycin-resistant (HLSR), high-level gentamicin-resistant (HLGR) and ampicillin-resistant (AR), respectively. Among HLSR isolates, 40 (56.3), 5 (7.0) and 26 (36.6) were E. faecium, E. faecalis and other Enterococcus spp., respectively. Among HLGR isolates 4 (36.4) and 7 (63.6) and among AR isolates 7 (70.0) and 3 (30.0) were E. faecium and other Enterococcus spp., respectively. Accordingly, 21.6, 3.6 and 3.3 of subjects were colonised with HLSR, HLGR and AR Enterococcus spp. Carriage of HLGR, HLSR and AR isolates was associated with prior antibiotic consumption (P � 0.05). Additionally, male sex and antacid consumption were associated with AR enterococcal carriage. Moreover, 69 (97.2), 10 (90.9) and 9 (90.0) of HLSR, HLGR and AR isolates were multidrug-resistant, respectively. No vancomycin-resistant enterococci were detected. ERIC-PCR revealed high genetic diversity among isolates. gelE and asa1 were major virulence genes both in E. faecalis and E. faecium. Presence of gelE was associated with HLSR and HLGR phenotypes (P � 0.05). Conclusion: Community intestinal carriage of HLSR enterococci was high; however, carriage of HLGR and AR enterococci was low. © 2019 International Society for Antimicrobial Chemotherap
Is morphology in Cercospora a reliable reflection of generic affinity?
Cercospora (Mycosphaerellaceae) is a large genus of fungi comprising many important plant pathogens. In recent years
DNA-based studies have revealed multiple genera of cercosporoid fungi being poly- and paraphyletic. Among these genera,
the genus Cercospora has always been perceived as monophyletic. In the present study, phylogenetic inferences based on
partial gene sequences of the LSU, ITS, ACT, TEF1-α and HIS loci, elucidated a cercospora-like taxon from Ammi majus to
cluster in a clade apart from Cercospora s. str. In spite of numerous Cercospora spp. presently known from their DNA sequence
data, this collection represents the first concrete evidence to the fact that the morphological characters previously attributed
to Cercospora s. str. evolved more than once in the Mycosphaerellaceae. The genus Neocercospora is subsequently
introduced to accommodate the Iranian taxon occurring on A. majus. Further collections on other hosts and from different
continents are now required to establish the prevalence and relative importance of species of Neocercospora.Laboratory of Evolutionary Phytopathology, CBS-KNAW Fungal Biodiversity Centre, the Research Deputy of the University of Tabriz and the Studienstiftung für mykologische
Systematik und Ökologie.http://www.mapress.com/phytotaxahb201
Application of the consolidated species concept to Cercospora spp. from Iran
The genus Cercospora includes many important plant pathogenic fungi associated with leaf spot diseases
on a wide range of hosts. The mainland of Iran covers various climatic regions with a great biodiversity of vascular
plants, and a correspondingly high diversity of cercosporoid fungi. However, most of the cercosporoid species found
to date have been identified on the basis of morphological characteristics and there are no cultures that support
these identifications. In this study the Consolidated Species Concept was applied to differentiate Cercospora species
collected from Iran. A total of 161 Cercospora isolates recovered from 74 host species in northern Iran were studied
by molecular phylogenetic analysis. Our results revealed a rich diversity of Cercospora species in northern Iran.
Twenty species were identified based on sequence data of five genomic loci (ITS, TEF1-α, actin, calmodulin and
histone H3), host, cultural and morphological data. Six novel species, viz. C. convolvulicola, C. conyzae-canadensis,
C. cylindracea, C. iranica, C. pseudochenopodii and C. sorghicola, are introduced. The most common taxon was
Cercospora cf. flagellaris, which remains an unresolved species complex with a wide host range. New hosts were
recorded for previously known Cercospora species, including C. apii, C. armoraciae, C. beticola, C. cf. richardiicola,
C. rumicis, Cercospora sp. G and C. zebrina.The Research Deputy of the University of Tabriz, the
Studienstiftung für mykologische Systematik und Ökologie and the CBSKNAW
Fungal Biodiversity Centre.http://www.ingentaconnect.com/content/nhn/pimjam201
Application of the consolidated species concept to Cercospora spp. from Iran
The genus Cercospora includes many important plant pathogenic fungi associated with leaf spot diseases
on a wide range of hosts. The mainland of Iran covers various climatic regions with a great biodiversity of vascular
plants, and a correspondingly high diversity of cercosporoid fungi. However, most of the cercosporoid species found
to date have been identified on the basis of morphological characteristics and there are no cultures that support
these identifications. In this study the Consolidated Species Concept was applied to differentiate Cercospora species
collected from Iran. A total of 161 Cercospora isolates recovered from 74 host species in northern Iran were studied
by molecular phylogenetic analysis. Our results revealed a rich diversity of Cercospora species in northern Iran.
Twenty species were identified based on sequence data of five genomic loci (ITS, TEF1-α, actin, calmodulin and
histone H3), host, cultural and morphological data. Six novel species, viz. C. convolvulicola, C. conyzae-canadensis,
C. cylindracea, C. iranica, C. pseudochenopodii and C. sorghicola, are introduced. The most common taxon was
Cercospora cf. flagellaris, which remains an unresolved species complex with a wide host range. New hosts were
recorded for previously known Cercospora species, including C. apii, C. armoraciae, C. beticola, C. cf. richardiicola,
C. rumicis, Cercospora sp. G and C. zebrina.The Research Deputy of the University of Tabriz, the
Studienstiftung für mykologische Systematik und Ökologie and the CBSKNAW
Fungal Biodiversity Centre.http://www.ingentaconnect.com/content/nhn/pimjam201
Pseudovirgaria, a fungicolous hyphomycete genus
The genus Pseudovirgaria, based on P. hyperparasitica, was recently introduced for a mycoparasite of rust sori of various species of Frommeëlla, Pucciniastrum and Phragmidium in Korea. In the present study, an older name introduced by Saccardo based on European material, Rhinotrichum griseum, is shown to resemble P. hyperparasitica. Morphological study and ITS barcodes from fresh collections of R. griseum from Austria on uredinia and telia of Phragmidium bulbosum on Rubus spp. reveal that it is distinct from P. hyperparasitica. The status of the genus Rhinotrichum, introduced for a fungus occurring on dry wood, remains unclear. Pseudovirgaria grisea comb. nov. is therefore proposed for the mycoparasite occurring on rust fungi in Europe, and an epitype is designated from the recent collections
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