Fungal diversity and occurrence of mycotoxin producing fungi in tropical vineyards

Nanoencapsulation with Eudragit® and chia mucilage increases the stability and antifungal efficacy of carvacrol against Aspergillus spp

Carvacrol is a consolidated natural antimicrobial. However, its use in food is a challenge due to characteristic odour and high volatility. Nanoencapsulation has emerged to overcome these drawbacks. Aspergillus spp. represent a concern in grapes for causing rot and producing mycotoxins. This study aimed to evaluate the effect of carvacrol (unencapsulated and loaded into Eudragit® and chia nanocapsules) on the growth of Aspergillus species. Spore germination and mycelial growth of Aspergillus spp. were evaluated using the agar dilution culture method. The stability of nanocapsules during storage was monitored monthly by evaluating the particle size distribution, polydispersity index, and zeta potential. Antifungal and antitoxigenic effectiveness of nanocapsules were assessed by counting fungal colony-forming units and determining mycotoxin levels in grapes. A dose-dependent effect of carvacrol (unencapsulated and encapsulated forms) on spore germination and mycelial growth was observed. During 180 days of storage, carvacrol into Eudragit® nanocapsules preserved their nanometric dimensions, whereas chia nanocapsules maintained this characteristic for 30 days. The antifungal effectiveness of both encapsulated forms persisted for 210 days. No mycotoxin was found, even when fungal growth was not completely suppressed. Nanoencapsulated carvacrol proved to be a new promising antifungal product to ensure quality and safety in the grape production chain.

Development of an Enzyme-Linked Immunosorbent Assay Based on a Monoclonal Antibody for the Rapid Detection of Citrinin in Wine

The ingestion of food contaminated with citrinin (CIT) poses a variety of health risks to humans and animals. The immunogens (CIT-COOH-BSA, CIT-H-BSA) and detection antigen (CIT-COOH-OVA, CIT-H-OVA) were synthesised using the active ester method (-COOH) and formaldehyde addition method (-H). A hybridoma cell line (3G5) that secretes anti-CIT monoclonal antibodies (mAbs) was screened via CIT-H-BSA immunisation of mice, cell fusion, and ELISA screening technology. The cell line was injected intraperitoneally to prepare ascites. The reaction conditions for the indirect competitive ELISA (ic-ELISA) were optimised, and an ic-ELISA method for detecting CIT was preliminarily established. The results revealed that the IC50 of CIT from optimised ic-ELISA was 37 pg/mL, the linear detection range was 5.9~230 pg/mL, and the cross-reaction (CR) rate with other analogues was less than 0.01%. The intra-assay and interassay sample recovery rates of CIT were 84.7~92.0% and 83.6~91.6%, and the coefficients of variation (CVs) were less than 10%. The ic-ELISA of CIT established in this study was not significantly different from the HPLC results and is rapid, highly sensitive and strongly specific, providing technical support for the detection of CIT.

Morphological and phylogenetic analyses reveal two new Penicillium species isolated from the ancient Great Wall loess in Beijing, China

Introduction

Penicillium species exhibit a broad distribution in nature and play a crucial role in human and ecological environments.

Methods

Two Penicillium species isolated from the ancient Great Wall loess in the Mentougou District of Beijing, China, were identified and described as new species, namely, Penicillium acidogenicum and P. floccosum, based on morphological characteristics and phylogenetic analyses of multiple genes including ITS, BenA, CaM, and RPB2 genes.

Results

Phylogenetic analyses showed that both novel species formed a distinctive lineage and that they were most closely related to P. chrzaszczii and P. osmophilum, respectively.

Discussion

Penicillium acidogenicum is characterized by biverticillate conidiophores that produce globose conidia and is distinguished from similar species by its capacity to grow on CYA at 30°C. Penicillium floccosum is typically recognized by its restricted growth and floccose colony texture. The description of these two new species provided additional knowledge and new insights into the ecology and distribution of Penicillium.

Taxonomic analysis reveals host preference of rare fungi in endophytes of Vitis vinifera from the Czech Republic

This paper represents the results of screening a diversity of fungal endophytes associated with Vitis vinifera leaves and canes in the Czech Republic. The characterization of strains is based on morphological and phylogenetic analyses of ITS, EF1α and TUB2 sequence data. Our strain selection covers 16 species and seven orders belonging to Ascomycota and Basidiomycota. Together with ubiquitous fungi, we report on several poorly known plant-associated fungi, Angustimassarina quercicola (= A. coryli, a synonym proposed in this study) and Pleurophoma pleurospora. Other species, such as Didymella negriana, D. variabilis, Neosetophoma sp. (species identical or sister to N. rosae), Phragmocamarosporium qujingensis and Sporocadus rosigena, have so far been little known and rarely found, but are frequent on V. vinifera in different parts of the world and obviously belong to a microbiota with a strong preference for this plant. Detailed taxonomical identification allowed us to identify species with apparent stable associations with V. vinifera, for which further interactions with V. vinifera can be expected. Our study is the first to focus on V. vinifera endophytes in Central Europe and expands the knowledge about their taxonomy, ecology and geography.

Fungal Diversity and Composition of the Continental Solar Saltern in Añana Salt Valley (Spain)

The Añana Salt Valley in Spain is an active continental solar saltern formed 220 million years ago. To date, no fungal genomic studies of continental salterns have been published, although DNA metabarcoding has recently expanded researchers' ability to study microbial community structures. Accordingly, the aim of this present study was to evaluate fungal diversity using the internal transcribed spacer (ITS) metabarcoding at different locations along the saltern (springs, ponds, and groundwater) to describe the fungal community of this saline environment. A total of 380 fungal genera were detected. The ubiquity of Saccharomyces was observed in the saltern, although other halotolerant and halophilic fungi like Wallemia, Cladosporium, and Trimmatostroma were also detected. Most of the fungi observed in the saltern were saprotrophs. The fungal distribution appeared to be influenced by surrounding conditions, such as the plant and soil contact, cereal fields, and vineyards of this agricultural region.