Two efficient methods for isolation of high-quality genomic DNA from entomopathogenic fungi

Evidence of the Ability of Microsatellite Method to Distinguish Cannabis Strains with High Cannabinoid Content

Introduction: Cannabis is a plant with high potential for use in several sectors of the industry; however, it is also a controversial crop due to its tetrahydrocannabinol (THC) content. Moreover, the plant has a rather unclarified classification. Traditionally, two types of Cannabis have been distinguished, hemp as a source of fiber and low THC content, and marijuana with high THC levels, which is used as a drug. With the increasing use of CBD strains and wide range of commercially used THC strains, it is becoming paramount to be able to develop an easy and reliable method for Cannabis strain differentiation. The use of simple sequence repeat markers, or microsatellites, seems to be an applicable choice. Materials and Methods: In this study, 52 strains of Cannabis with variable cannabinoid content were collected from growers from different geographical regions and analyzed using 17 different microsatellite markers. For more precise differentiation, five strains were selected and a higher number of individuals of each were analyzed. Results: Fragment analysis and cluster analysis showed that when one to three individual plants per strain were analyzed, the method was able to classify these samples into distinguishable groups with similar gene structure. They also revealed that when a larger sample set was used (10 individual plants per strain), highly specific strain clusters could be fully discriminated. Conclusion: Our study involved the highest number of cannabinoid-rich strains up to now and showed that the microsatellite method can be used to reliably differentiate Cannabis strains and show their relationships.

Investigation the biological activities and the metabolite profiles of endophytic fungi isolated from Gundelia tournefortii L

Endophytic fungi are microorganisms that are considered as a potential source of natural compounds, and can be applied in various industries. The aims of this research were molecular identification of endophytic fungi isolated from the Gundelia tournefortii stems, and investigation their biological activities as well as phenolic and fatty acid profile. Surface sterilized stems of G. tournefortii were placed on potato dextrose agar (PDA) to isolate the fungal endophytes. Genomic DNA was extracted by CTAB method, and PCR amplification was performed by ITS 1 and ITS 4 as primers. The enzyme production of endophytic fungi was determined based on the formation of a clear zone that appeared around the colonies of fungus. The anti-oxidant activity was evaluated by measuring the amount of free radicals DPPH. Also, the total phenol and flavonoid contents were measured obtained by Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. Moreover, the separation and identification of phenolic acids and fatty acids were done by HPLC and GC, respectively. Phylogenetic analysis was done based on the Internal Transcribed Spacer (ITS) region, and five isolates were identified as following: Aspergillus niger, Penicillium glabrum, Alternaria alternata, A. tenuissima, and Mucor circinelloides. Evaluation of the enzymatic properties showed that P. gabrum (31 ± 1.9 mm), and A. niger (23 ± 1.7) had more ability for producing pectinase and cellulase. The anti-oxidant activity of isolates showed that A. alternata extract (IC50 = 471 ± 29 µg/mL) had the highest anti-oxidant properties, followed by A. tenuissima extract (IC50 = 512 ± 19 µg/mL). Also, the extract of A. alternata had the greatest amount of total phenols and flavonoids contents (8.2 ± 0.4 mg GAL/g and 2.3 ± 0.3 mg QE/g, respectively). The quantification analysis of phenolic acid showed that rosmarinic acid, para-coumaric acid, and meta-coumaric acid (42.02 ± 1.31, 7.53 ± 0.19, 5.41 ± 0.21 mg/g, respectively) were the main phenolic acids in the studied fungi. The analysis of fatty acids confirmed that, in all fungi, the main fatty acids were stearic acid (27.9-35.2%), oleic acid (11.3-17.3%), palmitic acid (16.9-23.2%), linoleic acid (5.8-11.6%), and caprylic acid (6.3-10.9%). Our finding showed that endophytic fungi are a source of bioactive compounds, which could be used in various industries. This is the first report of endophytic fungi associated with G. tournefortii, which provides knowledge on their future use on biotechnological processes.

Fungal pathogens causing postharvest fruit rot of wolfberry and inhibitory effect of 2,3-butanedione

Fungal pathogen contamination is one of the most important factors affecting the postharvest quality and shelf life of wolfberry fruits. Therefore, the prevention and control of fungal pathogens that cause fruit rot has become particularly important. Volatile antifungal agents of biological origin have broad application prospects. They may be safer and more efficient than traditional physical and chemical methods. Four pathogenic fungi were isolated and purified from rotting wolfberry. These pathogenic fungi were determined to be Mucor circinelloides LB1, Fusarium arcuatisporum LB5, Alternaria iridiaustralis LB7, and Colletotrichum fioriniae LB8. In vitro fumigation experiments showed that 2,3-butanedione can effectively inhibit the mycelial growth, spore germination, and sporulation ability of pathogenic fungi. The scanning electron microscope (SEM) showed morphological changes in hyphae. Propidium iodide (PI) Staining and leakage of 260 and 280 nm-absorbing increased, suggesting damage to cell membranes. Furthermore, 2,3-butanedione was found to significantly improve fruit firmness, soluble solid, total phenol, flavonoid, and soluble sugar content, as well as higher SOD enzyme activity and lower PPO and POD enzyme activity in the treated fruit, indicating that 2,3-butanedione can effectively reduce the adverse effects of pathogenic fungi in wolfberry. Based on these results, we conclude that 2,3-butanedione is effective against infection by pathogenic fungi in post-harvest wolfberry. 2,3-butanedione should be considered a viable substitute for conventional fungicides that are currently used to control rot in wolfberry.

Evaluation of Native Entomopathogenic Fungi for the Control of Fall Armyworm (Spodoptera frugiperda) in Thailand: A Sustainable Way for Eco-Friendly Agriculture

Fall armyworm, Spodoptera frugiperda, entered Thailand in late 2018 and has now spread in several regions, with devastating effects in maize and rice production, which are some of the most important cereals in the world. Since then, farmers have utilized the available chemical insecticides to try to control it, but their efforts have been futile. Instead, they have ended up using extraordinary dosages, hence threatening non-target species and other fauna and flora, as well as being costly. In this regard, research has been ongoing, aiming to come up with eco-friendly solutions for this insect. We surveyed and collected various isolates of native entomopathogenic fungi intending to test their efficacy against fall armyworm. Six isolates of entomopathogenic fungi were obtained and identified to Beauveria bassiana based on morphological characteristics and multi-gene phylogenetic analyses. Thereafter, the six isolates of B. bassiana were used to perform efficacy experiments against fall armyworm. Additionally, the glycosyl transferase-like protein 1 (GAS1) gene was analyzed. Consequently, all the isolates showed efficacy against S. frugiperda, with isolate BCMU6 causing up to 91.67% mortality. Further, molecular analysis revealed that all the isolates possess the GAS1 gene, which contributed to their virulence against the insect. This is the first report of utilizing native entomopathogenic B. bassiana to manage S. frugiperda in Thailand, with the revelation of GAS1 as a factor in inducing virulence and cuticle penetration. This study has provided valuable information on the potential development of Beauveria bassiana as an eco-friendly bioinsecticide for the management of fall armyworm in Thailand.

Diversity and chemical fingerprinting of endo-metabolomes from endophytes associated with Ampelopsis grossedentata (Hand.-Mazz.) W. T. Wang possessing antibacterial activity against multidrug resistant bacterial pathogens

BACKGROUND

Serious infections caused by bacteria and their resistance to antibiotics are one of the biggest healthcare threats to mankind. Therefore, the present study aimed to isolate endophytes from medicinal plant Ampelopsis grossedentata, an endemic species of Western Hubei, China and to investigate its antibacterial efficacy and chemical diversity of the secondary metabolites.

METHODS

The antibacterial potential of the endophytes was evaluated by disc diffusion method against a panel of eleven type strains and some multidrug resistant pathogenic bacteria. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were estimated by broth microdilution using iodonitrotetrazolium chloride assay. Further, the chemical diversity of the metabolites was estimated using LC-Q-TOF-MS/MS and GC-MS fingerprinting.

RESULTS

Four endophytic fungi were isolated from the tender shoot of A. grossedentata; they were identified as Fusarium graminearum TC-1, Phomopsis mali TC-3, Pestalotiopsis maculans TC-5 and Alternaria alternata TC-11. Among the endophytes screened, A. alternata TC-11 exhibited significant antibacterial activity with the zones of inhibition ranging from 13.72 ± 0.30 to 21.76 ± 0.53 mm against all the tested type strains and multidrug resistant bacterial pathogens. Further, it showed significant antibacterial activity with MIC values ranging from 0.37 to 3.00 μg/mL. The combined LC-Q-TOF-MS/MS and GC-MS analyses of active extract revealed that alternarian acid, altertenuol, dimethyl sulfone, docosane, dodecane, duclauxin, ergosta-4,6,8(14),22-tetraen-3-one, ethyl 6-cyano-5-oxo-1-phenyl-7-thiophen-2-yl-[1,2,4]triazolo[4,3-a]pyrimidine-3-carboxylate, heptacosane, linoleic acid, neodecanoic acid, oxiranylmethyl ester, pentadecane, verrulactone E, 2,6,11-Trimethyldodecane and 4-[(E,4R,6R)-11-(furan-3-yl)-6-hydroxy-4,8-dimethylundec-8-enyl]-2-hydroxy-2H-furan-5-one were the most abundant compounds present which were responsible for the significant antibacterial activity.

CONCLUSIONS

To our knowledge, this is the first report of fungal endophytes isolated from the tender shoot of A. grossedentata with bacteriostatic and bactericidal activities. Our finding provides a new insight into the antibacterial potential of endophytes and envisages the possibility of using them for drug discovery.

Introduction of a bead beating step improves fungal DNA extraction from selected patient specimens

In immunocompromised patients a colonisation with fungi carries the risk to develop serious invasive fungal infection. An early detection is therefore important, but not optimal hitherto. Fortunately, molecular genetic methods have increased the sensitivity of fungal detection and limited the time, until results are available. However, their success depends on an efficient extraction of genomic DNA from the fungal cell in the given diagnostic specimen. To improve the routine DNA preparation method for yeasts and moulds, the impact of bead beating on fungal DNA release was evaluated. PBS, blood and respiratory rinse were spiked with Candida glabrata or Aspergillus fumigatus. DNA was extracted by mechanical bead beating in addition to the different steps of the DNA preparation protocol, which comprised liquid nitrogen treatment, proteinase K digestion and DNA isolation using the EZ1 DNA Tissue Kit and Workstation. In every method variant tested, treatment with liquid nitrogen did not improve the DNA release. Bead beating once followed by proteinase K digestion and EZ1-work-up led to the highest DNA release from fungus, spiked in PBS, and increased the extracted DNA amount of C. glabrata about 100-fold and of A. fumigatus about 10-fold in relation to sole EZ1-work-up. In fungus-spiked respiratory rinse and blood, highest increase in DNA release was measured after triple bead beating with simultaneous proteinase K digestion. Fungal DNA release of C. glabrata increased for >100-fold in respiratory rinse and for >1000-fold in blood and of A. fumigatus for >10-fold in respiratory rinse and about 5- to 10-fold in blood. The data of this study clearly demonstrate that preparation of fungal DNA from human specimens is optimized by introduction of a bead beating step to the conventional DNA-preparation method without the necessity of a liquid nitrogen step.

Meta-Analysis and Evaluation by Insect-Mediated Baiting Reveal Different Patterns of Hypocrealean Entomopathogenic Fungi in the Soils From Two Regions of China

A survey was carried out on forest soils and grassland soils from Hebei and Sichuan provinces using Tenebrio molitor larvae as a bait, and high-throughput DNA sequencing (HTS) of the fungal internal transcribed spacer-2 ribosomal DNA was used to monitor the natural distribution of three leading hypocrealean families of insect fungal pathogens (Clavicipitaceae, Cordycipitaceae, and Ophiocordycipitaceae). The occurrence of insect fungal pathogens in soil samples from 98 different sites was compared. The use of insect bait indicated that entomopathogenic fungi of the genus Metarhizium were predominant, followed by Beauveria and Isaria. Molecular characterization using the Mz_FG543 intergenic region revealed that the Metarhizium species pool was phylogenetically composed of three closely related species as follows; Metarhizium pingshaense (n = 74), Metarhizium robertsii (n = 51), and Metarhizium brunneum (n = 26), as well as one isolate which clustered with Metarhizium flavoviride. Nine potentially new phylogenetic species were delimited within the M. flavoviride species complex by sequencing of the 5′ elongation factor-1 alpha region locus. The Beauveria (n = 64) and Isaria (n = 5) isolates were characterized via sequence analyses of the Bloc region. An intergenic spacer phylogeny of the Beauveria isolate assemblage revealed the phylogenetic species within the Beauveria bassiana clade. Interestingly, the individuals of M. pingshaense (n = 18) and M. brunneum (n = 12) exhibited the presence of both mating types in Sichuan Province. Similarly, for the Beauveria isolates, reproductive mode assays demonstrated that all four B. bassiana subclades possessed bipolar outcrossing mating systems. Of these, 19 isolates contained two mating types, and the rest were fixed for single mating types, revealing opportunities for intra-lineage heterothallic mating. The HTS results showed a significantly higher occurrence of the Clavicipitaceae family and the Metarhizium genus in the soil samples. The Venn diagram showed Metarhizium anisopliae (senso lato), Isaria farinose, and B. bassiana as frequently abundant fungal pathogen operational taxonomic units (core) across sampling sites, while the baiting method showed that the genus of Isaria was isolated locally. The Mantel test verified that community dissimilarity increased significantly with geographical distance, suggesting that geographical coordinates are possible factors that influence the insect fungal pathogen community composition in the studied sites. This study is the first to highlight the usefulness of utilizing soil baiting and deep sequencing to investigate the population dynamics of entomopathogens in soil.

Shedding Light on the Diversity of Surfactant Interactions with Luminol Electrochemiluminescence for Bioanalysis

Luminol is a major probe for chemiluminescence (CL) and electrochemiluminescence (ECL) detection technologies in (bio)analysis. Surfactants are added to ECL assay cocktails to enhance signals or are present, owing to given bioassay protocols, yet little is known regarding their effects on luminol ECL. In-depth understanding is provided here through a broad study with bioanalytically relevant surfactants (cationic, anionic, and nonionic), four common electrode materials, and two luminol derivatives. Naturally, in ECL, surface effects are dominant; however, bulk solution, diffusion, and luminescence-stabilization processes also contribute significantly to the overall reaction. It was found that in contrast to CL the effect surfactants have on luminol ECL cannot be linked to general surfactant characteristics such as ionic nature, hydrophilic lipophilic balance (HLB) value, and critical micellar concentration (CMC). Instead, surfactants act in an all-encompassing mechanism, including surface electrochemistry, their solution and interfacial phases, and the chemical luminescence pathway. This leads to dramatic differences in signals obtained, ranging from 5-fold increases to total quenching. Within this complexity, we defined six guiding principles that are extrapolated from the underlying mechanisms and selection guides for surfactant, electrode, and environmental condition combinations. Those will now assist in developing highly sensitive luminol-ECL-based bioassays, because the surfactant selection can be based not only on properties needed for the assay protocol but also on identifying the optimal electrode-surfactant pair to maximize detection efficiency.