Quantum recurrent neural networks for sequential learning.

Quantum neural network (QNN) is one of the promising directions where the near-term noisy intermediate-scale quantum (NISQ) devices could find advantageous applications against classical resources. Recurrent neural networks are the most fundamental networks for sequential learning, but up to now there is still a lack of canonical model of quantum recurrent neural network (QRNN), which certainly restricts the research in the field of quantum deep learning. In the present work, we propose a new kind of QRNN which would be a good candidate as the canonical QRNN model, where, the quantum recurrent blocks (QRBs) are constructed in the hardware-efficient way, and the QRNN is built by stacking the QRBs in a staggered way that can greatly reduce the algorithm's requirement with regard to the coherent time of quantum devices. That is, our QRNN is much more accessible on NISQ devices. Furthermore, the performance of the present QRNN model is verified concretely using three different kinds of classical sequential data, i.e., meteorological indicators, stock price, and text categorization. The numerical experiments show that our QRNN achieves much better performance in prediction (classification) accuracy against the classical RNN and state-of-the-art QNN models for sequential learning, and can predict the changing details of temporal sequence data. The practical circuit structure and superior performance indicate that the present QRNN is a promising learning model to find quantum advantageous applications in the near term.

Genome Assembly and Pathway Analysis of Edible Mushroom Agrocybe cylindracea.

Agrocybe cylindracea, an edible mushroom, is widely cultivated for its abundance of nutrients and flavor, and many of its metabolites are reported to have beneficial roles, such as medicinal effects on tumors and chronical illnesses. However, the lack of genomic information has hindered further molecular studies on this fungus. Here, we present a genome assembly of A. cylindracea together with comparative genomics and pathway analyses of Agaricales species. The draft, generated from both next-generation sequencing (NGS) and single-molecule real-time (SMRT) sequencing platforms to overcome high genetic heterozygosity, is composed of a 56.5 Mb sequence and 15,384 predicted genes. This mushroom possesses a complex reproductive system, including tetrapolar heterothallic and secondary homothallic mechanisms, and harbors several hydrolases and peptidases for gradual and effective degradation of various carbon sources. Our pathway analysis reveals complex processes involved in the biosynthesis of polysaccharides and other active substances, including B vitamins, unsaturated fatty acids, and N-acetylglucosamine. RNA-seq data show that A. cylindracea stipes tend to synthesize carbohydrate for carbon sequestration and energy storage, whereas pilei are more active in carbon utilization and unsaturated fatty acid biosynthesis. These results reflect diverse functions of the two anatomical structures of the fruiting body. Our comprehensive genomic and transcriptomic data, as well as preliminary comparative analyses, provide insights into the molecular details of the medicinal effects in terms of active compounds and nutrient components.

Neutral Lipid Content in Lipid Droplets: Potential Biomarker of Cordycepin Accumulation in Cordycepin-Producing Fungi.

To clarify the relationship between neutral lipid content and cordycepin accumulation in Cordyceps militaris, mutants were generated from mixed spores of two C. militaris strains with varying cordycepin-producing capacities. Fifteen stable mutants producing from 0.001 to 2.363 mg/mL cordycepin were finally selected. The relative fluorescence intensities of the 15 mutants, two C. militaris strains and an Aspergillus nidulans strain at different concentrations of lyophilized mycelium powder were then investigated using the Nile red method. The mutant CM1-1-1 with the highest relative fluorescence intensity among the eighteen strains was selected for optimizing the Nile red method. Relative fluorescence intensity was linearly correlated with cordycepin concentration in liquid broth (R2 = 0.9514) and in lyophilized mycelium powder (R2 = 0.9378) for the 18 cordycepin-producing strains under identical culture conditions and with cordycepin concentration in liquid broth (R2 = 0.9727) and in lyophilized mycelium powder (R2 = 0.9613) for CM1-1-1 under eight different sets of conditions. In addition, the cordycepin content in lyophilized mycelium powder measured by the Nile red method was linearly correlated with that determined by an HPLC method (R2 = 0.9627). In conclusion, neutral lipids in lipid droplets are required during cordycepin accumulation; these neutral lipids are potential biomarkers of cordycepin biosynthesis.

Characterization of rhizosphere and endophytic fungal communities from roots of Stipa purpurea in alpine steppe around Qinghai Lake.

Stipa purpurea is among constructive endemic species in the alpine steppe on the Qinghai-Xizang Plateau. To reveal the fungal community structure and diversity in the rhizosphere and roots of this important grass and to analyze the potential influence of different habitats on the structure of fungal communities, we explored the root endophyte and the directly associated rhizosphere communities of S. purpurea by using internal transcribed spacer rRNA cloning and sequencing methods. We found that the roots of S. purpurea are associated with a diverse consortium of Basidiomycota (59.8%) and Ascomycota (38.5%). Most fungi obtained from rhizosphere soil in S. purpurea have been identified as Ascomycetes, while the high proportion detected in roots were basidiomycetous endophytes. The species richness, diversity, and evenness of fungal assemblages were higher in roots than in the rhizosphere soil. Fungi inhabiting the rhizosphere and roots of S. purpurea are significantly different, and the rhizosphere and endophyte communities are largely independent with little overlap in the dominant phyla or operational taxonomic units. Taken together, these results suggested that a wide variety of fungal communities are associated with the roots and rhizosphere soil of S. purpurea and that the fungal assemblages are strongly influenced by different habitats.