Pathogenic Fungal Species Research Articles

Synthesis, spectral characterization, DNA interaction, antioxidant, and antimicrobial studies of new water soluble metal(II) complexes of morpholine based ligand

A new series of metal(II) complexes 1–5 of the type [M(L)(AcO)2H2O], where L is a bidentate ligand, 2-(3-morpholinopropylimino)methylphenol and M is Mn(II) (1), Co(II) (2), Ni(II) (3), Cu(II) (4), and Zn(II) (5), have been isolated and characterized by physico-chemical and spectral methods. Spectroscopic data supported the square pyramidal geometry around the central metal ion in the complexes 1–5. Absorption spectra and viscometric data indicated that the complexes 1–5 interacted with calf thymus (CT) DNA via intercalative strategy. Cleavage activities of complexes 1–5 with CT DNA were analyzed by gelelectrophoretic method. The in vitro antioxidant activity of complexes 1–5 was tested using the DPPH assay. The complexes 1–5 have been tested for antimicrobial activity against some pathogenic bacterial and fungal species by the agar well diffusion method.

Distribution of Alternaria species on blighted potato and tomato leaves in Russia

Alternaria species are the causal agents of potato and tomato early blight disease. Three species-specific PCR primer sets were designed for Alternaria alternata sensu lato, Alternaria solani and Alternaria infectoria identification. The specificity of primers was confirmed by the absence of amplified products after PCR with DNA of Alternaria spp., other potato and tomato pathogenic fungal species and plant DNA. Constructed primers were applied for the survey of early blight agents on affected potato and tomato leaves collected in different regions of Russia. All three Alternaria pathogens were present in blighted leaves alone or in complex (A. alternata + A. solani, A. infectoria + A. alternata and A. solani + A. infectoria). Alternaria alternata (sensu lato) was the most abundant species. It was detected in 50% of tested potato leaves and 41% of tested tomato leaves (alone or in complex). Alternaria solani was found in 30 and 35% leaves, respectively. Alternaria infectoria occurred in potato and tomato samples occurred at a somewhat lower frequency (13 and 8%, respectively). Using the specific primers, it was possible to exclude the Alternaria disease in some leaves with symptoms similar to early blight.

Antifungal properties of essential oils against anthracnose disease: a critical appraisal

The present reviewed work on antifungal properties of EOs against following fungal pathogens of anthracnose disease is critically appraised over the period of last 16 years (2000–2016) that encompass both etiology and epidemiology of anthracnose in tropical fruits; current status of the main EOs and their specific volatile compounds such as terpenes, aromatic compounds, nitrogenous compounds were identified for their antifungal properties, when used at specific minimum inhibition concentration against species of the Colletotrichum genera of anthracnose disease; mechanisms of action of these major EOs for their antifungal activity were discussed. The major inferences drawn from this critical appraisal reviewed are the antifungal properties and the good fumigant nature of the above-mentioned essential oils and their specific volatile compounds from various plant species that inhibits postharvest fungal growth of Colletotrichum species such as Colletotrichum gloeosporioides Penz., Colletotrichum acutatum Colletotrichum fragaria, Colletotrichum musae of anthracnose disease in different tropical fruits in in vitro conditions. Till now, the researchers of the reported work reviewed did not pay attention toward further characterization of bioactive molecules with antifungal properties either from these listed EOs or their specific bioactive compounds. No cited work reported on in vitro screening and testing for their individual and synergistic effects even on in vivo testing their efficacies as the biochemical fungicide against said pathogenic fungal species of anthracnose. This reviewed knowledge on above topic could be used as future research tools to trace out the biochemical fungicides from various medicinal and aromatic plant sources as the alternative to synthetic chemical fungicides.

Candida parapsilosis Secreted Lipase as an Important Virulence Factor.

The prevalence of Candida parapsilosis, an opportunistic human pathogenic fungal species, is increasing at an alarming rate in the hospital environment. Patients at risk for C. parapsilosis infection include those with immunosuppression, such as individuals with cancer, AIDS, and low birth weight premature neonates as well as patients that had undergone abdominal surgery. Neonatal candidiasis caused by C. parapsilosis has been widely reported across the globe. Various reports have shown that, compared to other Candida species, certain C. parapsilosis clinical isolates were less susceptible to antifungals such as amphotericin B, fluconazole, and caspofungin. In addition, some studies have even reported multi-echinocandin or multi-azole resistant strains of C. parapsilosis. C. parapsilosis has several virulence factors that contribute to its capacity for host invasion and among these factors extracellular lipases have a major role in pathogenesis. In this review we have collected all the recent relevant studies that confirm the involvement of secreted lipases in C. parapsilosis pathogenesis, using both in vitro and in vivo models of infection. Of particular note, an available lipase deficient C. parapsilosis strain has been utilized to demonstrate that the lack of secreted lipases decreased virulence, reduced tissue damage, and was less able to survive within phagocytes or mice compared to the wild type. Since fungal secreted lipases have different characteristics than lipolytic enzymes present in humans, C. parapsilosis extracellular lipases may be potential targets for the development of novel antifungal drugs.

Inventaire Des Champignons Pathogènes Post-Récolte De La Banane Dessert « Cavendish » Et Evaluation De Leur Sensibilité A l’Azoxystrobine En Côte d’Ivoire

This study was aimed at drawing up an inventory of the post-harvest pathogenic fungi of banana dessert and to assess their susceptibility to Azoxystrobin. A sampling was carried out in banana fruit processing factories of the main Ivorian zones of banana production (Niéky, AboissoAyamé-Akressi and Tiassalé). The identification and frequency of isolation of the fungal species associated with the affected parts of the fruit was based on their cultural aspects, reproductive structures and percentage of contamination. The susceptibility of post-harvest fungi to different doses of Azoxystrobin 3.5, 4 and 4.5 g/hl was compared to a reference product, Bitertanol at a dose of 2 g/hl and to a check where only water is applied. Of the 13 pathogenic fungal species isolated, Botryodiplodia theobromae was the most recurrent and was identified as the main causal agent of postharvest rots. It is followed by Colletotrichum musae, Aspergillus niger, Fusarium moniliforme, Geotrichum candidum, Fusarium semitectum and Aspergillus flavus, in which the isolation frequencies are significantly different. The results on the susceptibility of pathogenic fungi to Azoxystrobin show that the three doses of Azoxystrobin have significantly different effects from that of the reference product and the check. They reduce infection rates up to 91.67% and give a high proportion of marketable fruits, respectively. Surprisingly, the dose of the reference product gives a low rate of reduction of infections (49%) and a proportion of marketable fruit that is significantly identical to that of water treatment.

Taxonomic evaluation of selected Ganoderma species and database sequence validation.

Species in the genus Ganoderma include several ecologically important and pathogenic fungal species whose medicinal and economic value is substantial. Due to the highly similar morphological features within the Ganoderma, identification of species has relied heavily on DNA sequencing using BLAST searches, which are only reliable if the GenBank submissions are accurately labeled. In this study, we examined 113 specimens collected from 1969 to 2016 from various regions in Korea using morphological features and multigene analysis (internal transcribed spacer, translation elongation factor 1-α, and the second largest subunit of RNA polymerase II). These specimens were identified as four Ganoderma species: G. sichuanense, G. cf. adspersum, G. cf. applanatum, and G. cf. gibbosum. With the exception of G. sichuanense, these species were difficult to distinguish based solely on morphological features. However, phylogenetic analysis at three different loci yielded concordant phylogenetic information, and supported the four species distinctions with high bootstrap support. A survey of over 600 Ganoderma sequences available on GenBank revealed that 65% of sequences were either misidentified or ambiguously labeled. Here, we suggest corrected annotations for GenBank sequences based on our phylogenetic validation and provide updated global distribution patterns for these Ganoderma species.

Indoor airborne fungal pollution in newborn units in Turkey.

Pathogenic and/or opportunistic fungal species are major causes of nosocomial infections, especially in controlled environments where immunocompromised patients are hospitalized. Indoor fungal contamination in hospital air is associated with a wide range of adverse health effects. Regular determination of fungal spore counts in controlled hospital environments may help reduce the risk of fungal infections. Because infants have inchoate immune systems, they are given immunocompromised patient status. The aim of the present study was to evaluate culturable airborne fungi in the air of hospital newborn units in the Thrace, Marmara, Aegean, and Central Anatolia regions of Turkey. A total of 108 air samples were collected seasonally from newborn units in July 2012, October 2012, January 2013, and April 2013 by using an air sampler and dichloran 18% glycerol agar (DG18) as isolation media. We obtained 2593 fungal colonies comprising 370 fungal isolates representing 109 species of 28 genera, which were identified through multi-loci gene sequencing. Penicillium, Aspergillus, Cladosporium, Talaromyces, and Alternaria were the most abundant genera identified (35.14, 25.40, 17.57, 2.70, and 6.22% of the total, respectively).

The major Alternaria alternata allergen, Alt a 1: A reliable and specific marker of fungal contamination in citrus fruits

The ubiquitously present spores of Alternaria alternata can spoil a wide variety of foodstuffs, including a variety of fruits belonging to the Citrus genus. The major allergenic protein of A. alternata, Alt a 1, is a species-specific molecular marker that has been strongly associated with allergenicity and phytopathogenicity of this fungal species. This study aimed to evaluate the potential of the detection of Alt a 1 as a reliable indicator of A. alternata contamination in citrus fruits. To accomplish this aim, sixty oranges were artificially infected with a spore suspension of A. alternata. Internal fruit material was collected at different incubation times (one, two and three weeks after the fungal inoculation) and used for both total RNA extraction and protein extraction. Alt a 1 detection was then performed by polymerase chain reaction (PCR) amplification using Alt a 1 specific primers and by enzyme-linked immunosorbent assay (ELISA). The experimental model presented in this work was effective to simulate the typical Alternaria black rot phenotype and its progression. Although both PCR and ELISA techniques have been successfully carried out for detecting Alt a 1 allergen in A. alternata infected oranges, the PCR method was found to be more sensitive than ELISA. Nevertheless, ELISA results were highly valuable to demonstrate that considerable amounts of Alt a 1 are produced during A. alternata fruit infection process, corroborating the recently proposed hypothesis that this protein plays a role in the pathogenicity and virulence of Alternaria species. Such evidence suggests that the detection of Alt a 1 by PCR-based assay may be used as a specific indicator of the presence of pathogenic and allergenic fungal species, A. alternata, in fruits. This knowledge can be employed to control the fungal infection and mitigate agricultural losses as well as human exposure to A. alternata allergens and toxins.

Shifts in rhizosphere fungal community during secondary succession following abandonment from agriculture.

Activities of rhizosphere microbes are key to the functioning of terrestrial ecosystems. It is commonly believed that bacteria are the major consumers of root exudates and that the role of fungi in the rhizosphere is mostly limited to plant-associated taxa, such as mycorrhizal fungi, pathogens and endophytes, whereas less is known about the role of saprotrophs. In order to test the hypothesis that the role of saprotrophic fungi in rhizosphere processes increases with increased time after abandonment from agriculture, we determined the composition of fungi that are active in the rhizosphere along a chronosequence of ex-arable fields in the Netherlands. Intact soil cores were collected from nine fields that represent three stages of land abandonment and pulse labeled with 13CO2. The fungal contribution to metabolization of plant-derived carbon was evaluated using phospholipid analysis combined with stable isotope probing (SIP), whereas fungal diversity was analyzed using DNA-SIP combined with 454-sequencing. We show that in recently abandoned fields most of the root-derived 13C was taken up by bacteria but that in long-term abandoned fields most of the root-derived 13C was found in fungal biomass. Furthermore, the composition of the active functional fungal community changed from one composed of fast-growing and pathogenic fungal species to one consisting of beneficial and slower-growing fungal species, which may have essential consequences for the carbon flow through the soil food web and consequently nutrient cycling and plant succession.

Identification and Characterization of Pathogenic and Endophytic Fungal Species Associated with Pokkah Boeng Disease of Sugarcane.

Pokkah Boeng is a serious disease of sugarcane, which can lead to devastating yield losses in crop-producing regions, including southern China. However, there is still uncertainty about the causal agent of the disease. Our aim was to isolate and characterize the pathogen through morphological, physiological, and molecular analyses. We isolated sugarcane-colonizing fungi in Fujian, China. Isolated fungi were first assessed for their cell wall degrading enzyme capabilities, and five isolates were identified for further analysis. Internal transcribed spacer sequencing revealed that these five strains are Fusarium, Alternaria, Phoma, Phomopsis, and Epicoccum. The Fusarium isolate was further identified as F. verticillioides after Calmodulin and EF-1α gene sequencing and microscopic morphology study. Pathogenicity assay confirmed that F. verticillioides was directly responsible for disease on sugarcane. Co-inoculation of F. verticillioides with other isolated fungi did not lead to a significant difference in disease severity, refuting the idea that other cellulolytic fungi can increase disease severity as an endophyte. This is the first report characterizing pathogenic F. verticillioides on sugarcane in southern China.

Chemical Composition and Antifungal Activity of Hedera Helix Leaf Ethanolic Extract

The 50% ethanol extract obtained from Hedera helix leaves was investigated regarding the presence and quantity of polyphenols, sterols and in vitro antifungal activity against phytopathogenic fungi. The chemical analysis revealed the presence of rutin, quercetin and kaempferol in the non-hydrolysed sample and quercetin and kaempferol in the hydrolysed sample and stigmasterol in the ivy leaf extract (nonhydrolysed sample). The antifungal activity against phytopathogenic fungi (Aspergillus niger, Botrytis cinerea, B. tulipae, Fusarium oxysporum f. sp. tulipae, Penicillium gladioli, and Sclerotinia sclerotiorum) was assessed using an agar dilution assay. The results are expressed as the minimum inhibitory concentration (MIC = 10–14%) and were compared to a synthetic antifungal drug–fluconazole (MIC = 8–30%). This report presents the first screening of the antifungal activity of the ivy leaf extract on these plant pathogenic fungi species, aiming to use the ivy leaf extract for controlling different diseases of vegetables and ornamental plants, in addition to human disorders.

Investigation of antioxidant, antimicrobial and toxicity activities of lichens from high altitude regions of Nepal

BackgroundSeveral lichen species are reported to be used tradiationally in many theraupatic practices. Many lichen species are reported as sources of several bioactive natural compounds. Several lichen species of Nepal are so far chemically unexplored.MethodsThe morphological, anatomical and phytochemical characteristics of lichens were compared for the taxonomic identification of the species. Methanol- water extract of lichens were sub fractionated into hexane, dichloromethane and methanol fractions for bioactivity assays. Antimicrobial activities of extracts were evaluated agaisnt pathogenic bacteria and fungal species. DPPH test was used for antioxidant potential evaluation. Brineshrimp test was perfermed to evaluate toxicity of the extracts.ResultsA total of 84 lichen specimens were collected and identified from Annapurna Conservation Area (ACA) Nepal. The specimens were identified as belonging to 19 genera and 47 species. Methanol fractions of 16 specimens and dichloromethane (DCM) fractions of 21 lichens specimens showed antioxidant activities comparable with commercial standards (BHA, Butylated hydroxyanisole, IC50=4.9±0.9 μg/mL) even at crude extract level. Similarly, the DCM fraction of 17 lichens showed potential antimicrobial activity against a Gram-positive bacterium (Staphylococcus aureus KCTC3881) and DCM fractions of 45 lichens showed antimicrobial activity against a Gram-negative bacterium (Klebsiella pneumoniae KCTC2242). DCM fractions of three lichens showed antifungal activity against the yeast, Candida albicans KCTC 7965. Likewise, methanol fractions of 39 lichens and DCM fractions of 74 lichens showed strong toxicity against brine shrimp nauplii with more than 80% mortality.ConclusionSuch biological activity-rich lichen specimens warrant further research on exploration of natural products with antioxidant, antimicrobial and anti cancer (toxic) potential.

Development of Real-Time Isothermal Amplification Assays for On-Site Detection of Phytophthora infestans in Potato Leaves.

Real-time loop-mediated isothermal amplification (LAMP) and recombinase polymerase amplification (RPA) assays were developed targeting the internal transcribed spacer 2 region of the ribosomal DNA of Phytophthora infestans, the potato late blight causal agent. A rapid crude plant extract (CPE) preparation method from infected potato leaves was developed for on-site testing. The assay's specificity was tested using several species of Phytophthora and other potato fungal and oomycete pathogens. Both LAMP and RPA assays showed specificity to P. infestans but also to the closely related species P. andina, P. mirabilis, P. phaseoli, and P. ipomoeae, although the latter are not reported as potato pathogen species. No cross-reaction occurred with P. capsici or with the potato pathogens tested, including P. nicotianae and P. erythroseptica. The sensitivity was determined using P. infestans pure genomic DNA added into healthy CPE samples. Both LAMP and RPA assays detected DNA at 50 fg/μl and were insensitive to CPE inhibition. The isothermal assays were tested with artificially inoculated and naturally infected potato plants using a Smart-DART platform. The LAMP assay effectively detected P. infestans in symptomless potato leaves as soon as 24 h postinoculation. A rapid and accurate on-site detection of P. infestans in plant material using the LAMP assay will contribute to improved late blight diagnosis and early detection of infections and facilitate prompt management decisions.

Electromagnetic Processing as a Way of Increasing Microbiological Safety of Animal Waste

The article shows the possibility of using the electromagnetic field of ultrahigh frequency (EMF UHF) for drying and disinfecting of such animal waste as pig manure and poultry droppings. The studied modes included the following options: processing exposure of 60, 90, 120 sec, the capacity of 60 kW, the frequency of 915 MHz. The method of UHF processing of manure and poultry droppings is environmentally safe and effective in neutralizing the pathogenic microflora, as well as larvae and eggs of worms. The following processing mode of animal waste in the electromagnetic field of ultrahigh frequency was recognized as optimal: exposure of 90 seconds, the capacity of 60 kW, the frequency of 915 MHz. This option leads to the complete destruction of pathogenic and conditionally pathogenic microorganisms, as well as the eggs and larvae of worms. As a result of this processing, a high level of microbiological safety of pig manure and poultry droppings is achieved that allows using them as organic fertilizers. The peculiarities of some species of pathogenic fungi developing on the surface of the wheat grain are shown. Pre-processed animal waste (pig manure and and poultry droppings) were applied in experimental variants. Used organic fertilizers underwent electromagnetic processing of ultra-high frequency. The qualitative composition of the microflora on the surface of the grain depends on the type of animal waste (manure or droppings) and used dose. The safest part of the microflora of grain was marked with the application of the UHF-processed pig manure and poultry droppings in doses of 10 t/ha.

Chromoblastomycosis caused by Rhinocladiella similis: Case report

We report a case of chromoblastomycosis in lesions on the chest and foot. Itraconazole was chosen as the initial treatment for this patient, who was followed up for 8 months before becoming noncompliant. The pathogenic fungal species was identified as Rhinocladiella similis by ITS region sequencing. In vitro analyses indicate that the fungus was sensitive to posaconazole and itraconazole. This report presents R. similis as a new agent of chromoblastomycosis and raises the hypothesis that this species could be more resistant to some antifungals than R. aquaspersa.

Stabilization of nano-structured ZnO particles onto the surface of cotton fibers using different surfactants and their antimicrobial activity

ZnO NPs were prepared and deposited onto cotton fibers via ultrasound irradiation successfully. Different surfactants (SDS, HY, CTAB, TX-100) have been used to stabilize, homogenize the coated ZnO NPs and control their shape and size as encapsulated species. The use of surfactants has improved the durability of ZnO NPs and decreased its leaching in particular SDS. The small mean crystallite size for ZnO particles due to the use of surfactants is the main reason for decreasing the leached of ZnO particles from cotton substrate. SEM and XRD analysis revealed information about the shape and size of the coated ZnO nanoparticles. The use of SDS and HY surfactants in the synthesis of ZnO NPs coated fabrics showed the highest antibacterial and antifungal activities against different pathogenic bacterial and fungal species with high reduction reached over 90%.

Chemical Composition and Antifungal Activity of Essential Oils from Flowers, Leaves, Rhizomes, and Bulbs of the Wild Iraqi Kurdish Plant Iris Persica

Essential oils-obtained by hydrodistillation of different parts of Iris persica L. were investigated for the first time by GC-FID and GC-MS; moreover, their antifungal activities were determined: 34,. 32, 27, and 17 compounds were identified in the oils from air-dried flowers, leaves, rhizomes and fresh. bulbs, respectively, representing ≥ 98% each oil. The major constituents of the flower essential oil were phenylethanol (24.8%) and furfural (13.8%), which, as the main component, constituted also 39.0% and 22.2% of the leaf and rhizome volatile fractions, respectively. Phenylacetaldehyde (37.1%) was the main constituent of the bulb volatile fraction. In in vitro tests, moderate antifungal activity was detected for the oils against strains of the human pathogenic fungal species Gandida albicans, Microsporum canis, and Trichophyton mentagrophytes, the plant-fungal pathogen Pyricularia oryzae, and the fungal food contaminant Aspergillus carbonarius,. The highest activity was exhibited by the essential oils from leaves and flowers, suggesting that they could be considered natural antimicrobial agents.

Plant Pathogenic Fungi.

Fungi are among the dominant causal agents of plant diseases. To colonize plants and cause disease, pathogenic fungi use diverse strategies. Some fungi kill their hosts and feed on dead material (necrotrophs), while others colonize the living tissue (biotrophs). For successful invasion of plant organs, pathogenic development is tightly regulated and specialized infection structures are formed. To further colonize hosts and establish disease, fungal pathogens deploy a plethora of virulence factors. Depending on the infection strategy, virulence factors perform different functions. While basically all pathogens interfere with primary plant defense, necrotrophs secrete toxins to kill plant tissue. In contrast, biotrophs utilize effector molecules to suppress plant cell death and manipulate plant metabolism in favor of the pathogen. This article provides an overview of plant pathogenic fungal species and the strategies they use to cause disease.

A plant pathology perspective of fungal genome sequencing

The majority of plant pathogens are fungi and many of these adversely affect food security. This minireview aims to provide an analysis of the plant pathogenic fungi for which genome sequences are publicaNy available, to assess their general genome characteristics, and to consider how genomics has impacted plant pathology. A list of sequenced fungal species was assembled, the taxonomy of all species verified, and the potential reason for sequencing each of the species considered. The genomes of 1090 fungal species are currently (October 2016) in the public domain and this number is rapidly rising. Pathogenic species comprised the largest category (35.5 %) and, amongst these, plant pathogens are predominant. Of the 191 plant pathogenic fungal species with available genomes, 61.3 % cause diseases on food crops, more than half of which are staple crops. The genomes of plant pathogens are slightly larger than those of other fungal species sequenced to date and they contain fewer coding sequences in relation to their genome size. Both of these factors can be attributed to the expansion of repeat elements. Sequenced genomes of plant pathogens provide blueprints from which potential virulence factors were identified and from which genes associated with different pathogenic strategies could be predicted. Genome sequences have also made it possible to evaluate adaptability of pathogen genomes and genomic regions that experience selection pressures. Some genomic patterns, however, remain poorly understood and plant pathogen genomes alone are not sufficient to unravel complex pathogen-host interactions. Genomes, therefore, cannot replace experimental studies that can be complex and tedious. Ultimately, the most promising application lies in using fungal plant pathogen genomics to inform disease management and risk assessment strategies. This will ultimately minimize the risks of future disease outbreaks and assist in preparation for emerging pathogen outbreaks.

Identification of small molecules that disrupt vacuolar function in the pathogen Candida albicans.

The fungal vacuole is a large acidified organelle that performs a variety of cellular functions. At least a sub-set of these functions are crucial for pathogenic species of fungi, such as Candida albicans, to survive within and invade mammalian tissue as mutants with severe defects in vacuolar biogenesis are avirulent. We therefore sought to identify chemical probes that disrupt the normal function and/or integrity of the fungal vacuole to provide tools for the functional analysis of this organelle as well as potential experimental therapeutics. A convenient indicator of vacuolar integrity based upon the intracellular accumulation of an endogenously produced pigment was adapted to identify Vacuole Disrupting chemical Agents (VDAs). Several chemical libraries were screened and a set of 29 compounds demonstrated to reproducibly cause loss of pigmentation, including 9 azole antifungals, a statin and 3 NSAIDs. Quantitative analysis of vacuolar morphology revealed that (excluding the azoles) a sub-set of 14 VDAs significantly alter vacuolar number, size and/or shape. Many C. albicans mutants with impaired vacuolar function are deficient in the formation of hyphal elements, a process essential for its pathogenicity. Accordingly, all 14 VDAs negatively impact C. albicans hyphal morphogenesis. Fungal selectivity was observed for approximately half of the VDA compounds identified, since they did not alter the morphology of the equivalent mammalian organelle, the lysosome. Collectively, these compounds comprise of a new collection of chemical probes that directly or indirectly perturb normal vacuolar function in C. albicans.