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In the present study, we investigated the effects of chronic exposure (14 and 28 days) to a 0.5 mT 50 Hz extremely low-frequency magnetic field (ELM) on the dendritic spine density and shape in the superficial layers of the medial entorhinal cortex (MEC). We performed Golgi staining to reveal the dendritic spines of the principal neurons in rats. The results showed that ELM exposure induced a decrease in the spine density in the dendrites of stellate neurons and the basal dendrites of pyramidal neurons at both 14 days and 28 days, which was largely due to the loss of the thin and branched spines. The alteration in the density of mushroom and stubby spines post ELM exposure was cell-type specific. For the stellate neurons, ELM exposure slightly increased the density of stubby spines at 28 days, while it did not affect the density of mushroom spines at the same time. In the basal dendrites of pyramidal neurons, we observed a significant decrease in the mushroom spine density only at the later time point post ELM exposure, while the stubby spine density was reduced at 14 days and partially restored at 28 days post ELM exposure. ELM exposure-induced reduction in the spine density in the apical dendrites of pyramidal neurons was only observed at 28 days, reflecting the distinct vulnerability of spines in the apical and basal dendrites. Considering the changes in spine number and shape are involved in synaptic plasticity and the MEC is a part of neural network that is closely related to learning and memory, these findings may be helpful for explaining the ELM exposure-induced impairment in cognitive functions.

Fresh fruits and vegetables can harbor large and diverse populations of bacteria. However, most of the work on produce-associated bacteria has focused on a relatively small number of pathogenic bacteria and, as a result, we know far less about the overall diversity and composition of those bacterial communities found on produce and how the structure of these communities varies across produce types. Moreover, we lack a comprehensive view of the potential effects of differing farming practices on the bacterial communities to which consumers are exposed. We addressed these knowledge gaps by assessing bacterial community structure on conventional and organic analogs of eleven store-bought produce types using a culture-independent approach, 16 S rRNA gene pyrosequencing. Our results demonstrated that the fruits and vegetables harbored diverse bacterial communities, and the communities on each produce type were significantly distinct from one another. However, certain produce types (i.e., sprouts, spinach, lettuce, tomatoes, peppers, and strawberries) tended to share more similar communities as they all had high relative abundances of taxa belonging to the family Enterobacteriaceae when compared to the other produce types (i.e., apples, peaches, grapes, and mushrooms) which were dominated by taxa belonging to the Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria phyla. Although potentially driven by factors other than farming practice, we also observed significant differences in community composition between conventional and organic analogs within produce types. These differences were often attributable to distinctions in the relative abundances of Enterobacteriaceae taxa, which were generally less abundant in organically-grown produce. Taken together, our results suggest that humans are exposed to substantially different bacteria depending on the types of fresh produce they consume with differences between conventionally and organically farmed varieties contributing to this variation.

Psychedelic drugs have a long history of use in healing ceremonies, but despite renewed interest in their therapeutic potential, we continue to know very little about how they work in the brain. Here we used psilocybin, a classic psychedelic found in magic mushrooms, and a task-free functional MRI (fMRI) protocol designed to capture the transition from normal waking consciousness to the psychedelic state. Arterial spin labeling perfusion and blood-oxygen level-dependent (BOLD) fMRI were used to map cerebral blood flow and changes in venous oxygenation before and after intravenous infusions of placebo and psilocybin. Fifteen healthy volunteers were scanned with arterial spin labeling and a separate 15 with BOLD. As predicted, profound changes in consciousness were observed after psilocybin, but surprisingly, only decreases in cerebral blood flow and BOLD signal were seen, and these were maximal in hub regions, such as the thalamus and anterior and posterior cingulate cortex (ACC and PCC). Decreased activity in the ACC/medial prefrontal cortex (mPFC) was a consistent finding and the magnitude of this decrease predicted the intensity of the subjective effects. Based on these results, a seed-based pharmaco-physiological interaction/functional connectivity analysis was performed using a medial prefrontal seed. Psilocybin caused a significant decrease in the positive coupling between the mPFC and PCC. These results strongly imply that the subjective effects of psychedelic drugs are caused by decreased activity and connectivity in the brain's key connector hubs, enabling a state of unconstrained cognition.

Oyster mushrooms are an interesting source of biologically active glucans and other polysaccharides. This work is devoted to the isolation and structural characterization of polysaccharides from basidiocarps of the cultivated oyster mushroom, Pleurotus ostreatus. Five polysaccharidic fractions were obtained by subsequent extraction with cold water, hot water and two subsequent extractions with 1 m sodium hydroxide. Branched partially methoxylated mannogalactan and slightly branched (1→6)-β-d-glucan predominated in cold- and hot-water-soluble fractions, respectively. Alternatively, these polysaccharides were obtained by only hot water extraction and subsequent two-stage chromatographic separation. The alkali-soluble parts originating from the first alkali extraction were then fractionated by dissolution in dimethyl sulfoxide (DMSO). The polysaccharide insoluble in DMSO was identified as linear (1→3)-α-d-glucan, while branched (1→3)(1→6)-β-d-glucans were found to be soluble in DMSO. The second alkaline extract contained the mentioned branched β-d-glucan together with some proteins. Finally, the alkali insoluble part was a cell wall complex of chitin and β-d-glucans.

The family Russulaceae is considered an iconic lineage of mostly mushroom-forming basidiomycetes due to their importance as edible mushrooms in many parts of the world, and their ubiquity as ectomycorrhizal symbionts in both temperate and tropical forested biomes. Although much research has been focused on this group, a comprehensive or cohesive synthesis by which to understand the functional diversity of the group has yet to develop. Interest in ectomycorrhizal fungi, of which Russulaceae is a key lineage, is prodigious due to the important roles they play as plant root mutualists in ecosystem functioning, global carbon sequestration, and a potential role in technology development toward environmental sustainability. As one of the most species-diverse ectomycorrhizal lineages, the Russulaceae has recently been the focus of a dense sampling and genome sequencing initiative with the Joint Genome Institute aimed at untangling their functional roles and testing whether functional niche specialization exists for independent lineages of ectomycorrhizal fungi. Here we present a review of important studies on this group to contextualize what we know about its members' evolutionary history and ecosystem functions, as well as to generate hypotheses establishing the Russulaceae as a valuable experimental system.

Macrofungus is defined as the fungus that grows an observable sporocarp. The sporocarps of many species are commonly called mushrooms and consumed by people all around the world as food and/or medicine. Most macrofungi belong to the divisions Basidiomycetes and Ascomycetes, which are estimated to contain more than 80,000 species in total. We report the draft genome assemblies of macrofungi (83 Basidiomycetes species and 7 Ascomycetes species) based on Illumina sequencing. The genome sizes of these species ranged from 27.4 Mb ( Hygrophorus russula ) to 202.2 MB ( Chroogomphus rutilus ). The numbers of protein-coding genes were predicted in the range of 9,511 ( Hygrophorus russula ) to 52,289 ( Craterellus lutescens ). This study provides the largest genomic dataset for macrofungi species. This resource will facilitate the artificial cultivation of edible mushrooms and the discovery of novel drug candidates.

The genetic manipulation of basidiomycete mushrooms is notoriously difficult and immature, and there is a lack of research reports on clustered regularly interspaced short palindromic repeat (CRISPR) based gene editing of functional genes in mushrooms. In this work, Ganoderma lucidum, a famous traditional medicinal basidiomycete mushroom, which produces a type of unique triterpenoid-anti-tumor ganoderic acids (GAs), was used, and a CRISPR/CRISPR-associated protein-9 nuclease (Cas9) editing system for functional genes of GA biosynthesis was constructed in the mushroom. As proof of concept, the effect of different gRNA constructs with endogenous u6 promoter and self-cleaving ribozyme HDV on ura3 disruption efficiency was investigated at first. The established system was applied to edit a cytochrome P450 monooxygenase (CYP450) gene cyp5150l8, which is responsible for a three-step biotransformation of lanosterol at C-26 to ganoderic acid 3-hydroxy-lanosta-8, 24-dien-26 oic acid. As a result, precisely edited cyp5150l8 disruptants were obtained after sequencing confirmation. The fermentation products of the wild type (WT) and cyp5150l8 disruptant were analyzed, and a significant decrease in the titer of four identified GAs was found in the mutant compared to WT. Another CYP gene involved in the biosynthesis of squalene-type triterpenoid 2, 3; 22, 23-squalene dioxide, cyp505d13, was also disrupted using the established CRISPR-Cas9 based gene editing platform of G. lucidum. The work will be helpful to strain molecular breeding and biotechnological applications of G. lucidum and other basidiomycete mushrooms.

Among the most important sources of β-glucans are edible and medicinal mushrooms. These molecules are components of the cellular wall of basidiomycete fungi (mushrooms) and can be extracted even from the basidiocarp as the mycelium and its cultivation extracts or biomasses. Mushroom β-glucans are recognized by their potential effects as immunostimulants and immunosuppressants. They are highlighted as anticholesterolemic, anti-inflammatory, adjuvant in diabetes mellitus, mycotherapy for cancer treatment, as well as adjuvants for COVID-19 vaccines. Due to their relevance, several techniques of β-glucans extraction, purification, and analysis have already been described. Despite the previous knowledge of β-glucans’ benefits for human nutrition and health, the main information about this topic refers to the molecular identification, properties, and benefits, as well as their synthesis and action on cells. Studies on biotechnology industry applications (product development) and the registered products of β-glucans from mushrooms are still limited and more common for feed and healthcare. In this context, this paper reviews the biotechnological production of food products containing β-glucans from basidiomycete fungi, focusing on food enrichment, and presents a new perspective on fungi β-glucans’ use as potential immunotherapy agents.Key points• Mushrooms’ β-glucans for product development in the biotechnology industry• Biotechnological production of food products containing mushrooms’ β-glucans• Basidiomycete fungi β-glucans are used as potential immunotherapy agents

Many fungi are polykaryotic, containing multiple nuclei per cell. In the case of heterokaryons, there are different nuclear types within a single cell. It is unknown what the different nuclear types contribute in terms of mRNA expression levels in fungal heterokaryons. Each cell of the mushroom Agaricus bisporus contains two to 25 nuclei of two nuclear types originating from two parental strains. Using RNA-sequencing data, we assess the differential mRNA contribution of individual nuclear types and its functional impact. We studied differential expression between genes of the two nuclear types, P1 and P2, throughout mushroom development in various tissue types. P1 and P2 produced specific mRNA profiles that changed through mushroom development. Differential regulation occurred at the gene level, rather than at the locus, chromosomal, or nuclear level. P1 dominated mRNA production throughout development, and P2 showed more differentially up-regulated genes in important functional groups. In the vegetative mycelium, P2 up-regulated almost threefold more metabolism genes and carbohydrate active enzymes (cazymes) than P1, suggesting phenotypic differences in growth. We identified widespread transcriptomic variation between the nuclear types of A. bisporus. Our method enables studying nucleus-specific expression, which likely influences the phenotype of a fungus in a polykaryotic stage. Our findings have a wider impact to better understand gene regulation in fungi in a heterokaryotic state. This work provides insight into the transcriptomic variation introduced by genomic nuclear separation.