Mitochondrial genome and diverse inheritance patterns in Pleurotus pulmonarius.

Pleurotus pulmonarius, a member of the Pleurotaceae family in Basidiomycota, is an edible, economically important mushroom in most Asian countries. In this study, the complete mitochondrial genomes (mtDNA) of three P. pulmonarius strains - two monokaryotic commercial (J1-13 and ZA3) and one wild (X1-15) - were sequenced and analyzed. In ZA3 and X1-15, the mtDNA molecule was found to be a single circle of 68,305 bp and 73,435 bp, respectively. Both strains contain 14 core protein-coding genes and two ribosomal RNA (rRNA) subunit genes. The ZA3 strain has 22 transfer RNA (tRNA) genes and nine introns: eight in cytochrome c oxidase subunit 1 (coxl), and one in the rRNA large subunit (rnl). Monokaryotic J1-13 and ZA3 mtDNAs were found to be similar in their structure. However, the wild strain X1-15 contains 25 tRNA genes and only seven introns in coxl. Open reading frames (ORFs) of ZA3/J1-13 and X1-15 encode LAGLIDADG, ribosomal protein S3, and DNA polymerase II. In addition, mtDNA inheritance in J1-13, ZA3, and X1-15 was also studied. Results showed that the mtDNA inheritance pattern was uniparental and closely related to dikaryotic hyphal location with respect to the parent. Results also show that mtDNA inheritance is influenced by both the parental nuclear genome and mitogenome in the zone of contact between two compatible parents. In summary, this analysis provides valuable information and a basis for further studies to improve our understanding of the inheritance of fungal mtDNA.

Comparative Transcriptomics of Flammulina filiformis Suggests a High CO2 Concentration Inhibits Early Pileus Expansion by Decreasing Cell Division Control Pathways.

Carbon dioxide is commonly used as one of the significant environmental factors to control pileus expansion during mushroom cultivation. However, the pileus expansion mechanism related to CO2 is still unknown. In this study, the young fruiting bodies of a popular commercial mushroom Flammulina filiformis were cultivated under different CO2 concentrations. In comparison to the low CO2 concentration (0.05%), the pileus expansion rates were significantly lower under a high CO2 concentration (5%). Transcriptome data showed that the up-regulated genes enriched in high CO2 concentration treatments mainly associated with metabolism processes indicated that the cell metabolism processes were active under high CO2 conditions. However, the gene ontology (GO) categories and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with cell division processes contained down-regulated genes at both 12 h and 36 h under a high concentration of CO2. Transcriptome and qRT-PCR analyses demonstrated that a high CO2 concentration had an adverse effect on gene expression of the ubiquitin-proteasome system and cell cycle-yeast pathway, which may decrease the cell division ability and exhibit an inhibitory effect on early pileus expansion. Our research reveals the molecular mechanism of inhibition effects on early pileus expansion by elevated CO2, which could provide a theoretical basis for a CO2 management strategy in mushroom cultivation.

Sequence and comparative analysis of the MIP gene in Chinese straw mushroom, Volvariella volvacea.

The mitochondrial intermediate peptidase (MIP) gene is conserved in fungi. It is linked closely with the mating-type A (mtA) gene. In this study, a fragment of the MIP gene in Volvariella volvacea (Bull. ex Fr.) Singer was first cloned by homologue-based cloning technology. Subsequently, the entire MIP DNA sequence (PYd21-MIP) was obtained after the fragment was compared with the genomic data through BLAST analysis. The PYd21-MIP sequence appeared to be homologous with the MIP gene in other fungi. Phylogenetic analysis of PYd21-MIP and other MIP sequences from diverse fungi agreed with the current organism phylogeny. Analysis of protein domains by InterProScan software and motif searching demonstrated that PYd21-MIP encodes a homologous MIP protein. These data support the hypothesis that the PYd21-MIP protein is a Hog-MIP protein homologue from V. volvacea.

Collective dipole oscillations of a spin-orbit coupled Bose-Einstein condensate.

In this Letter, we present an experimental study of the collective dipole oscillation of a spin-orbit coupled Bose-Einstein condensate in a harmonic trap. The dynamics of the center-of-mass dipole oscillation is studied in a broad parameter region as a function of spin-orbit coupling parameters as well as the oscillation amplitude. The anharmonic properties beyond the effective-mass approximation are revealed, such as the amplitude-dependent frequency and finite oscillation frequency at a place with a divergent effective mass. These anharmonic behaviors agree quantitatively with variational wave-function calculations. Moreover, we experimentally demonstrate a unique feature of the spin-orbit coupled system predicted by a sum-rule approach, stating that spin polarization susceptibility--a static physical quantity--can be measured via the dynamics of dipole oscillation. The divergence of polarization susceptibility is observed at the quantum phase transition that separates the magnetic nonzero-momentum condensate from the nonmagnetic zero-momentum phase. The good agreement between the experimental and theoretical results provides a benchmark for recently developed theoretical approaches.

Holographic storage of biphoton entanglement.

Coherent and reversible storage of multiphoton entanglement with a multimode quantum memory is essential for scalable all-optical quantum information processing. Although a single photon has been successfully stored in different quantum systems, storage of multiphoton entanglement remains challenging because of the critical requirement for coherent control of the photonic entanglement source, multimode quantum memory, and quantum interface between them. Here we demonstrate a coherent and reversible storage of biphoton Bell-type entanglement with a holographic multimode atomic-ensemble-based quantum memory. The retrieved biphoton entanglement violates the Bell inequality for 1 µs storage time and a memory-process fidelity of 98% is demonstrated by quantum state tomography.

Experimental demonstration of topological error correction.

Scalable quantum computing can be achieved only if quantum bits are manipulated in a fault-tolerant fashion. Topological error correction--a method that combines topological quantum computation with quantum error correction--has the highest known tolerable error rate for a local architecture. The technique makes use of cluster states with topological properties and requires only nearest-neighbour interactions. Here we report the experimental demonstration of topological error correction with an eight-photon cluster state. We show that a correlation can be protected against a single error on any quantum bit. Also, when all quantum bits are simultaneously subjected to errors with equal probability, the effective error rate can be significantly reduced. Our work demonstrates the viability of topological error correction for fault-tolerant quantum information processing.

[Isolation and identification of a bacterial strain JS018 capable of degrading several kinds of organophosphate pesticides].

Organophosphate pesticides are used widely all over the world and play an important role in plant pest control. However these pesticides are considered as pollutants and harmful to human health. To search for microorganisms that can degrade organophosphate pesticides with high efficiency, a bacterial strain, coded as JS018, was isolated and screened from the soil in the vicinity of Shanming Pesticides Factory, Shanming, Fujian. Laboratory tests showed that the bacterium could degrade several kinds of organophosphate pesticides, such as Parathion-methyl and phoxin. The strain's degrading rates on phoxin, Parathion-methyl, hostathion and dichlorvos in LB liquid fermentation medium for 36 h were 99%, 96%, 80.4% and 69.0% respectively. The bacterial colonies on LB plate appeared shiny and pale-pink in color. The bacteria were Gram-negative coccoids, 0.5 - 0.7 microm in diameter. They grew well at 30 - 38 degrees C and pH 7.0 - 9.0. The optimal temperature and pH for cell growth was 32 degrees C and pH 7.5 - 8.0, respectively. They did not grow in medium containing 6% or more NaCl. The antibiotic susceptibility tests showed that the strain was resistant to ampicillin, penicillin and lincomycin. It was sensitive to kanamycin, tetracycline and gentamicin. Laboratory tests also showed that the strain could ferment D-glucose, trehalose, melezitose and ethanol. It was negative in the production of indole and hydrogen sulfide. It could not liquefy gelatin, utilize citrate, nor ferment L-arabinose, sucrose, D-mannitol, D-xylose, fructose, D-galactose, maltose or lactose. The catalase, urease and nitrate reduction were positive. Based on its morphological, physiological and biochemical properties as well as the 16S rDNA sequence analysis result, the strain was tentatively identified as Roseomonas sp.