Aspergillus Welwitschiae Research Articles

Fate of Fumonisin B2 (FB2) during Vinification and Wine Storage: Fining Agents for the Removal of FB2 in Wine

Background and Aims. Fumonisins are a group of mycotoxins produced by some isolates of black aspergilli. This study examines the dynamics of fumonisins during winemaking and storage and the role of fining agents in the removal of FB2, the most prevalent fumonisin produced by black aspergilli. Methods and Results. Chardonnay grapes were inoculated with a fumonisin-producing strain of Aspergillus welwitschiae and fumonisins were quantified at different stages of vinification. The stability of fumonisins was studied at 13 and 25°C using Chardonnay wine spiked with FB2. Activated charcoal, calcium bentonite, yeast hulls, and a nonallergenic polysaccharide of nonanimal origin (NO (OX)) were evaluated as fining agents for FB2 removal from wine. Fumonisins were quantified by LC-MS/MS. During vinification most of the fumonisins were removed with the solids, with only 3% of the fumonisins found in the grapes being transferred to the wine. Fumonisin FB2 was stable in white wine for at least 4 months, but was reduced by 42% after 8 months at 25°C. Activated charcoal and bentonite were able to remove more than 80% of FB2 in white wine. Conclusions. Vinification can lead to the partial removal of fumonisins. The use of fining agents and wine storage leads to further reduction. Significance of the Study. This study demonstrates the fate of fumonisins during vinification and wine storage and the potential use of fining agents for amelioration of fumonisin contamination.

Phylogenomics and gene selection in Aspergillus welwitschiae: Possible implications in the pathogenicity in Agave sisalana

Aspergillus welwitschiae causes bole rot disease in sisal (Agave sisalana and related species) which affects the production of natural fibers in Brazil, the main worldwide producer of sisal fibers. This fungus is a saprotroph with a broad host range. Previous research established A. welwitschiae as the only causative agent of bole rot in the field, but little is known about the evolution of this species and its strains. In this work, we performed a comparative genomics analysis of 40 Aspergillus strains. We show the conflicting molecular identity of this species, with one sisal-infecting strain sharing its last common ancestor with Aspergillus niger, having diverged only 833 thousand years ago. Furthermore, our analysis of positive selection reveals sites under selection in genes coding for siderophore transporters, Sodium‑calcium exchangers, and Phosphatidylethanolamine-binding proteins (PEBPs). Herein, we discuss the possible impacts of these gene functions on the pathogenicity in sisal.

A Whole Genome Sequencing-Based Approach to Track down Genomic Variants in Itraconazole-Resistant Species of Aspergillus from Iran.

The antifungal resistance in non-fumigatus Aspergillus spp., as well as Aspergillus fumigatus, poses a major therapeutic challenge which affects the entire healthcare community. Mutation occurrence of cyp51 gene paralogs is the major cause of azole resistance in Aspergillus spp. To obtain a full map of genomic changes, an accurate scan of the entire length of the Aspergillus genome is necessary. In this study, using whole genome sequencing (WGS) technique, we evaluated the mutation in cyp51A, cyp51B, Cdr1B, AtrR, Hmg1, HapE and FfmA genes in different clinical isolates of Aspergillus fumigatus, Aspergillus niger, Aspergillus tubingensis, Aspergillus welwitschiae and Aspergillus terreus which responded to minimum inhibitory concentrations of itraconazole above 16 µg mL−1. We found different nonsynonymous mutations in the cyp51A, cyp51B, Cdr1B, AtrR, Hmg1, HapE and FfmA gene loci. According to our findings, Aspergillus species isolated from different parts of the world may represent different pattern of resistance mechanisms which may be revealed by WGS.

Aspergillus welwitschiae: A Potential amylases Producer.

Amylases, glycoside hydrolases widely used in several industrial processes, can be produced by many animals, plants, bacteria, and fungi. Fungal amylases from Aspergillus sp. hold remarkable importance in biotechnological applications for presenting a great catalysis efficiency in a wide range of pH and temperature. The production of amylases is mainly dependent on the genetic background of the species, i.e., Aspergillus strains, and abiotic factors. Among the major producers of amylases are the species of Aspergillus section Nigri, including Aspergillus welwitschiae. In this study, Aspergillus welwitschiae strains were evaluated for their ability to produce extracellular amylases. Among the 24 strains, wild Aspergillus welwitschiae UELAs 15.262 and mutant A. welwitschiae UELAs 15.262/35 strains showed greater potential for amylases production. The A. welwitschiae UELAs 15.262 produced more amylases (8645 U/mg) when compared to A. welwitschiae UELAs 15.262/35 (6666 U/mg). The amylases activity from partially purified crude enzymatic extract of A. welwitschiae UELAs 15.262 strain obtained at pH 5.5, 60°C, resulted in 1.98-fold (3837 U/mg) increase in enzymatic activity. Likewise, the amylases activity from partially purified crude extract of A. welwitschiae UELAs 15.262/35 obtained at pH 5.0, 60°C resulted in 2.2-fold (9077 U/mg) increase in amylases activity. The presence of metallic ions (Cu2+ and Fe3+) also provided an increase of amylases activity for both strains. To our knowledge, this is the first study reporting the ability of Aspergillus welwitschiae strains in order to produce amylases.

Aspergillus welwitschiae inulinase enzyme cocktails obtained on agro-material inducers for the purpose of fructooligosaccharides production

Production of fructooligosaccharides (FOS) is a trending topic due to their prebiotic effect becoming increasingly important for the modern human diet. The most suitable process for FOS production is the one using fungal inulinases. Introduction of new fungal inulinase producers and their implementation in production of inulinase enzymes is therefore gaining interest. This study provides a new approach to FOS synthesis by fungal enzyme complex without prior separation of any specific enzyme. Inulinase enzyme complexes could be used for the synthesis of FOS in two possible ways – hydrolysis of inulin (FOSh) and transfructosylation process of sucrose (FOSs), as demonstrated here. Depending on the fungal growth inducing substrate, a variety of inulinase enzyme complexes was obtained – one of which was most successful in production of FOSh and another one of FOSs. Substrates derived from crops: triticale, wheat bran, Jerusalem artichoke and Aspergillus welwitschiae isolate, previously proven as safe for use in food, were utilized for production of inulinase enzyme cocktails. The highest FOSs production was obtained by enzyme complex rich in β-fructofuranosidase, while the highest FOSh production was obtained by enzyme complex rich in endoinulinase. Both FOSh and FOSs showed antioxidant potential according to ABTS and ORAC, which classifies them as a suitable additive in functional food. Simultaneous zymographic detection of inulinase enzymes, which could contribute to expansion of the knowledge on fungal enzymes, was developed and applied here. It demonstrated the presence of different inulinase isoforms depending on fungal growth substrate. These findings, which rely on the innate ability of fungi to co-produce all inulinases from a cocktail, could be useful as a new, easy approach to FOS production by fungal enzymes without their separation and purification, contributing to cheaper and faster production processes.

Molecular identification and antifungal susceptibility of clinically relevant and cryptic species of Aspergillus sections Flavi and Nigri

Introduction. Aspergillus sections Flavi and Nigri comprise clinically relevant and cryptic species that differ significantly in drug susceptibility, meaning that effective treatment depends on correct species identification.Hypothesis/Gap Statement. There are no comprehensive data for molecular identification and antifungal susceptibility testing (AFST) of clinically relevant and cryptic species of Aspergillus sections Flavi and Nigri as the main agents of invasive and non-invasive aspergillosis in Iran. We aimed to perform molecular identification and AFST of 213 clinical Aspergillus isolates belonging to sections Flavi and Nigri. Molecular identification of isolates was performed using sequencing of the β-tubulin gene and in vitro AFST was conducted according to the Clinical and Laboratory Standards Institute (CLSI) M38-A3 guidelines.Results. The most common isolates in sections Flavi and Nigri were Aspergillus flavus (110/113, 97.3 %) and Aspergillus tubingensis (49/100, 49.0 %), respectively. A total of 62/213 (29.1 %) isolates belonging to cryptic species were identified; among them, A. tubingensis was the most prevalent (49/62, 79.0%). Aspergillus flavus and A. niger isolates that responded to the minimum inhibitory concentrations (MICs) of itraconazole above the epidemiological cutoff values were the most frequently detected: 8/110 (7.3 %) and 3/41 (7.3 %), respectively. In section Flavi, Aspergillus alliaceus responded to amphotericin B at a high MIC (>16 µg mL-1) and in section Nigri, one of the three Aspergillus luchuensis/awamori isolates responded to itraconazole at an MIC >16 µg ml-1. Interestingly, for all Aspergillus welwitschiae isolates, the MIC50 and MIC90 of itraconazole were both 16 µg ml-1.Conclusion. A considerable presence of A. flavus and A. niger isolates showing non-wild-type responses to azoles in clinical cases of aspergillosis indicates the importance of classifying clinical Aspergillus isolates at the species level and performing antifungal susceptibility testing on the isolates, which would ensure appropriate treatment.

Antibacterial Effect and Mode of Action of Secondary Metabolites from Fungal Endophyte Associated with Aloe ferox Mill

The constant increase in drug resistance, occurrence of incurable diseases and high medical costs, have necessitated bio-prospecting of fungi as alternative sources of therapeutic compounds. This study aimed at assessing the antibacterial effect and mode of action of secondary metabolites from fungal endophyte associated with Aloe ferox Mill. Endophytic fungus was isolated from the gel of A. ferox and identified by internal transcribed spacer (ITS) rRNA gene sequence analysis. The targets of antibacterial activity were assessed based on minimum inhibitory concentration (MIC) and the effect of the extract on respiratory chain dehydrogenase (RCD) and membrane integrity. Fourier transform-infrared spectrophotometer (FTIR) was employed to ascertain functional groups. The fungus with the most promising antibiotic-production was identified as Aspergillus welwitschiae MK450668.1. Its extract exhibited antibacterial activity with the MIC values of 0.5 and 1 mg/mL against Staphylococcus aureus (ATCC 25925) and Escherichia coli (ATCC 25922). It demonstrated the inhibitory effect on the RCD activity and destruction of membrane integrity on the test bacteria. FTIR spectrum revealed hydroxyl, amine and alkene groups. A. welwitschiae MK450668.1 serves as a potential source of effective compounds to combat the challenge of drug resistance.

Discovery of Tolerance to Itraconazole in Japanese Isolates of Aspergillus Section Nigri, Aspergillus tubingensis and Aspergillus welwitschiae, by Microscopic Observation.

Aspergillus section Nigri, a group of black Aspergillus, has several cryptic species that were recently discovered to be intrinsically resistant to azole antifungals. In this study, susceptibility testing of 35 clinical isolates of Aspergillus tubingensis and Aspergillus welwitschiae in Japan was carried out using microdilution method. Strains tolerant to itraconazole in A. tubingensis (14/17 strains) and A. welwitschiae (6/18 strains) were discovered with hyphal growth and conidial germination above the minimal inhibitory concentration by microscopic observation, while no resistant strain was observed macroscopically. In contrast, no strain with reduced susceptibility to voriconazole, posaconazole, and amphotericin-B was found. Further examination may be required to determine the susceptibility of cryptic species in Aspergillus section Nigri to antifungals.

Biosynthesis and characterizations of extracellular enzymes of microbial isolates from dairy industrial effluent

Diary effluents are environmental pollutant which could serve as source of substrate for microbial enzymes' synthesis. This research investigated the isolation and screening of bacteria and fungi with potential extracellular proteolytic and amylolytic properties from dairy effluents, and their characteristics for maximum enzyme production. Effluent from a dairy industry located in Ibadan, Nigeria, was collected for isolation and screening of microbial species for enzymatic activities. The Biological Oxygen Demand (BOD), Total Soluble Solid (TTS), and pH of the effluent were determined using standard procedures. The potential isolates were characterized morphologically and by molecular techniques. Proteolytic and amylolytic activities of isolates were investigated on skimmed milk starch agar respectively and optimized with varying pH (6.0 - 9.0), temperature (27 - 60 °C) and incubation period (12 - 72 h). Data were analyzed by Duncan Multiple Range Test. Biological Oxygen Demand, Total Soluble Solid and pH of the effluent were 14.67 mg/L, 13.33% and 7.58 respectively. Eleven isolates were positive for either protease or amylase synthesis, but only two showed both proteolytic and amylolytic activities and were molecularly characterized as Bacillus stratosphericus CM2HG6 and Aspergillus welwitschiae. Optimization showed that enzyme production by B. stratosphericus CM2HG6 was highest at 35 °C, pH 7.0 for 48 h, and that of A. welwitschiae achieved optimum production at 37 °C, pH 8.0 for 72 h. Under optimized conditions, Bacillus stratosphericus CM2HG6 was the highest amylase and protease producer (24.4 and 30.74 U/ml respectively), while A. welwitschiae was the lowest producer (12.58 and 18.8 U/ml respectively). The study successfully showed that these industrially-important enzymes can be produced by microbial strains isolated from dairy effluent, and production can be further optimized

Black mold of stored onion bulbs caused by Aspergillus welwitschiae

ISHS V International Symposium on Postharvest Pathology: From Consumer to Laboratory-Sustainable Approaches to Managing Postharvest Pathogens Black mold of stored onion bulbs caused by Aspergillus welwitschiae

Primary cutaneous aspergillosis caused by Aspergillus welwitschiae: A case report

Primary cutaneous aspergillosis caused by <i>Aspergillus welwitschiae</i>: A case report

Molecular characterisation of fungi associated with sewage-impacted soil

The decay of faecal matter from a septic system causes the arousal of fungi in the surrounding soil. These fungi can cause diseases if there is sewage spillage containing untreated or improperly treated wastewaters. Molecular techniques of identification of fungi have shown to be more dependable than traditional methods of identifying fungal species. This study was carried out to identify the fungal species associated with soil obtained from sewage-impacted soil near a septic tank using both traditional cultural techniques and molecular method. Fungi associated with the soil samples were isolated using serial dilution and Potato Dextrose Agar (PDA) method. Deoxyribonucleic Acid (DNA) was extracted from the pure cultures of fungal isolates using Quick DNA Fungal/Bacterial Miniprep kit. Polymerase Chain Reaction (PCR) amplification of internal transcribed spacer (ITS) region of the fungal isolates was carried out using universal primer pair; ITS4 and ITS5. The PCR products were sequenced and the sequences were blasted against National Centre for Biotechnology Information database. The result of the nucleotide sequence analysis revealed the identity of the isolates as Trichoderma harzanium with 580 base pairs and Aspergillus welwitschiae with 560 base pairs. Sequences of the isolates were aligned and compared with sequences on GenBank and a phylogenetic tree was constructed. The cultural method only aided in suggesting the suspected genera of the isolates while the molecular method was able to identify the isolates to the species level. This study will promote the knowledge of the fungal species associated with sewage-impacted soil and also aid researchers in proffering ways to enhance the prevention/control of diseases associated with sewage spill.&#x0D; Keyword: Septic tank, fungi, soil, phylogeny, sequencing

Prevalence of Non-Dermatophytic Molds Associated with Cutaneous Mycoses in Cattle in Abia and Imo States, Nigeria

Aims: To study the prevalence and identification of non-dermatophytic molds associated with cattle in Abia and Imo States, Nigeria.&#x0D; Study Design: The systematic random sampling method was adopted.&#x0D; Place and Duration of Study: A total of 2255 cattle was encountered, out of which 451 skin samples from both infected and asymptomatic animals were sampled from six cattle markets in Abia and Imo States, Nigeria between January and August, 2018.&#x0D; Methodology: The 451 samples were analysed for their colonial and microscopic morphology and molecular analysis. Polymerase chain reaction of the 16SrRNA internal transcriber spacer (ITS) sequence techniques were carried out on the isolates. Pathogenicity of the isolates were determined.&#x0D; Results: A total of 16 non-dermatophytic molds were obtained from 451samples analysed at different frequency of occurrences from the cattle skins in both states and these include Aspergillusfumigatus (3.6%), Aspergillus terreus (2.7%), Aspergillus wewitschiae (13.5%), Aspergillus flavus (10.0%), Aspergillus aculeatus (9.0%), Aspergillus sydowii (5.0%), Fusarium solani (3.2%), Fusarium lichenicola (17.9%), Fusarium succisae (12.0%), Fusarium oxysporum (2.0%), Penicillium citrinum (3.0%), Curvularia kusanol (0.6%), Cladosporium tenuissimum (4.9%), Pestalotiopsis microspora (0.1%), Talaromyces kendrickii (0.1%) and Absidia specie (12.9%).&#x0D; Conclusion: The study revealed that non-dermatophytic molds were highly prevalent and are possible causative agent of cutaneous mycoses in cattle. Pathogenicity evaluation carried out in this study revealed that Aspergillus welwitschiae, Cladosporium tenuissimum and Absidia sp. were highly virulent.

Endophytic bacteria isolated from both healthy and diseased Agave sisalana plants are able to control the bole rot disease

Sisal is an economically and socially significant perennial crop for the semiarid region of the world. Bole rot disease, caused by black aspergilli, mainly by Aspergillus welwitschiae, is responsible for great losses due to the ability of the pathogen to kill the plant. The health status of plants that harbor endophytic biocontrol agents (BCAs) is being investigated in this study. We conducted experiments with endophytic bacteria from different parts of healthy and diseased sisal plants to select potential BCAs to control the disease. Studies on the populational densities showed that leaves have less bacteria when compared to roots and stems, and that diseased plants tended to have higher populations of bacterial endophytes. These results were obtained with both conventional plate counting and qPCR. A total of 497 isolates were screened as potential biocontrol agents on sisal discs and nine were selected as having direct antagonistic activity. Five isolates were from healthy and four from diseased plant parts. All these nine isolates significantly decreased the bole rot disease incidence in two field experiments and were identified by sequencing of the 16S rDNA as species belonging in the genera Bacillus, Brevibacterium, Burkholderia (2 isolates), Paenibacillus, Pseudomonas and Serratia (3 isolates). Isolate 466 of Burkholderia lowered 80% of disease incidence in both field experiments, which was not significantly different from the non-inoculated, negative control. We discussed these findings under an ecological-physiological interaction standpoint, as well as the possibilities of including diseased plants in bioprospection strategies and applying the selected isolates in the development of bioproducts.

Isolation and Characterization of Fungi strains associated with Mycotoxin Production from Bambara (Vigna subterranea (L) verdc) nuts Recovered in Nigeria

Fungal contamination of food commodities is a global food security challenge that impacts negatively on the health of consumers. Mycotoxins are produced as secondary metabolites by some pathogenic fungi and may contaminate agricultural products while on the field or during harvesting and storage. A field survey was conducted in order to isolate and identify the mycotoxin-producing fungal strains in Bambara nut collected from major markets in eight States in Nigeria including Oyo, Ogun, Lagos, Ekiti, Kwara, Kogi, Abuja, and Nasarawa. Samples per site were pooled, processed and screened for the presence of mycotoxin-producing fungi by culture technique and intergenic spacer sequencing (ITS). Mycotoxin production was determined using thin layer chromatography (TLC) with scanning densitometer. Twenty-four mycotoxin-producing fungal species were isolated from Bambara samples, which were identified as Talaromyces pinophilus, Macrophomina phaseolina (6), Fusarium oxysporum (2), Aspergillus foetidus, Aspergillus flavipes, Rhizopus oryzae (2), Phanerochaete chrysosporium, Aspergillus flavus (2), Aspergillus terreus, Aspergillus awamori, Aspergillus welwitschiae, Rhizopus microsporus, Ceriporia lacerate and Fusarium verticillioides (accession numbers of MN42329- MN4233323) from Bambara nuts. The genera Macrophomina were the most dominant. Some of the identified fungi are noted for the production of mycotoxins and mycotoxins exert toxic effects on animals and humans. The fungi associated with Bambara nut diseases were identified and can be taken as targets in varietal improvement of Bambara nut for resistance to fungal diseases in Nigeria.

Mycotoxin-Producing Fungal Species Recovered from Melon Seed Marketed in Nigeria

Agricultural products may be contaminated by mycotoxin-producing pathogenic fungi while on the field or during harvesting and storage. A field survey was conducted in order to isolate and identify the mycotoxin-producing fungal strains in melon seeds collected from major markets in eight States in Nigeria. Samples per site were pooled, processed and screened for the presence of mycotoxin-producing fungi by culture technique and Internal transcribed spacer sequencing (ITS). Mycotoxin production was determined using thin-layer chromatography (TLC) with a scanning densitometer. Eighteen producing fungi species: Macrophomina phaseolina, Aspergillus foetidus, Aspergillus flavipes, Rhizopus oryzae, Aspergillus flavus, Aspergillus niger, Penicillium aurantiocandidum, Aspergillus awamori, Neurospora crassa, Aspergillus fischeri, Aspergillus flavus, Aspergillus tamarii, Aspergillus oryzae, Lichtheimia hyalospora, Aspergillus terreus, Rhizopus oryzae, Aspergillus welwitschiae, Aspergillus corrugatus were identified. These sequences with accession numbers between MN423295-MN423331 have been deposited at the National Center for Biotechnology Information (NCBI) database. The genera Macrophomina and were the most dominant. Some of the identified fungi are noted for the production of mycotoxins and mycotoxins exert toxic effects on animals and humans. The fungi associated to melon seeds diseases were identified and can be taken as targets in the varietal improvement of melon seeds for resistance to fungal diseases in Nigeria.

Screening of Aspergillus and Candida Species with Utmost Potential to Synthesize Citric Acid

Background: Citric acid production through fermentation is economical but meeting its increasing global demand has been challenging in recent times.&#x0D; Aim: This study aimed to screen Aspergillus and Candida sp. isolated from different sources with potentials of producing citric acid.&#x0D; Methodology: Aspergillus and Candida spp. were isolated from compost soil and fruits (cucumber and banana) and their morphological characteristics were described using standard microbiological methods. The isolates were quantitatively screened for citric acid production based on appearance of yellow zone of clearance for 3 days. All the isolates which had acid unitage (AU) values&gt; 5.0 were selected for further characterization using molecular methods.&#x0D; Results: Candida tropicalis, Aspergillus sp. A. niger and Penicillium sp. were isolated from the soil and fruit samples. The isolates screened for citric acid production displayed varying diameters of yellow zones around their colonies is indicative of varying capability of the microbial strains. A. niger from compost soil which had highest AU value of 8.5 at Day 3 demonstrated greatest potential to yield citric acid. Molecular characterization revealed high citric acid producing strains as Aspergillus niger (EU440768.1) and Aspergillus welwitschiae (MG669181.1).&#x0D; Conclusion: Although Aspergillus niger is widely utilized for industrial production of citric acid, this study has demonstrated that A. welwitschiae is a specie of Aspergillus capable of synthesizing citric acid reasonably.

Diversity and ochratoxin A-fumonisin profile of black Aspergilli isolated from grapes in China

Aspergillus spp. are a common contaminant of grapes and a major source of mycotoxins. China is the largest producer of grape in the world now, however, the toxigenicAspergillus population on grape in this country is still largely unknown. In this study, a total of 345 strains were isolated from grapes of 13 main grapevine producing regions in China. Based on calmodulin gene sequences, eight species withinAspergillus sectionNigri were identified. Among them,Aspergillus tubingensis (48.7%) was predominant, followed byAspergillus welwitschiae (20.6%) andAspergillus aculeatinus (11%). Average of contamination level was up to 64.19%, and we found the occurrence of sectionNigri species on the surface of fresh grapes was significantly influenced by the climate (P&lt;0.05). The subtropical monsoon climate showed the highest fungal detection rate (72.45%), followed by the temperate monsoon climate (49.82%), and the lowest frequency was found in the temperate continental climate (37.23%). Regarding mycotoxin-producing capacity, 4.4% of the total tested sectionNigri isolates (137) were positive for ochratoxin A (OTA) production and 59.6% were fumonisin B2 (FB2) producers. Of those,Aspergillus carbonarius was the main OTA producer andA. welwitschiae andAspergillus niger were the main FB2 producers with different toxigenic ability. Our results highlight the potential risk of OTA and FB2 contamination byA. carbonarius andA. welwitschiae on grape in China, respectively; management strategies should be considered for preventing and reducing the toxigenicAspergillus and its mycotoxins.

\u03b1\u03b2-Dehydrocurvularin isolated from the fungus Aspergillus welwitschiae effectively inhibited the behaviour and development of the root-knot nematode Meloidogyne graminicola in rice roots

BackgroundThe root-knot nematode Meloidogyne graminicola has become a serious threat to rice production as a result of the cultivation changes from transplanting to direct seeding. The nematicidal activity of Aspergillus welwitschiae have been investigated in vitro, and the disease control efficacy of the active compound has been evaluated under greenhouse and field conditions.ResultsThe active compound αβ-dehydrocurvularin (αβ-DC), isolated by nematicidal assay-directed fractionation, showed significant nematicidal activity against M. graminicola, with a median lethal concentration (LC50) value of 122.2 μg mL− 1. αβ-DC effectively decreased the attraction of rice roots to nematodes and the infection of nematodes and also suppressed the development of nematodes under greenhouse conditions. Moreover, αβ-DC efficiently reduced the root gall index under field conditions.ConclusionsTo our knowledge, this is the first report to describe the nematicidal activity of αβ-DC against M. graminicola. The results obtained under greenhouse and field conditions provide a basis for developing commercial formulations from αβ-DC to control M. graminicola in the future.

Polyketides from marine-derived Aspergillus welwitschiae inhibit Staphylococcus aureus virulence factors and potentiate vancomycin antibacterial activity in vivo

Staphylococcus aureus, a major cause of nosocomial and community associated infections, is becoming increasingly resistant to antibiotics. S. aureus infections are frequently biofilm-associated, and a diverse spectrum of virulence factors are determinant in the pathogenicity, which can be an interesting target resulting in less selective pressure for bacterial resistance. This study reports anti-virulence activity against S. aureus, including a MRSA clinical isolate, of naphto-γ-pyrones from Aspergillus welwitschiae mycelium, and the characterization of chemical constituents by LC-DAD and LC-MS. A remarkable decrease in biofilm formation, hemolysis and coagulation promoted by Staphylococcus aureus, important traits for bacterial pathogenicity, were observed. Furthermore, advantageous association with vancomycin resulted in significant protection against staphylococcal infection in Galleria mellonella model. These findings corroborate the importance of natural products as a source of new therapeutic possibilities, as well reveals potential alternatives for infection control using anti-virulence and drug association approaches.