A simple and effective method to discern the true commercial Chinese cordyceps from counterfeits.

The Chinese cordyceps, a complex of the fungus Ophiocordyceps sinensis and its species-specific host insects, is also called "DongChongXiaCao" in Chinese. Habitat degradation in recent decades and excessive harvesting by humans has intensified its scarcity and increased the prices of natural populations. Some counterfeits are traded as natural Chinese cordyceps for profit, causing confusion in the marketplace. To promote the safe use of Chinese cordyceps and related products, a duplex PCR method for specifically identifying raw Chinese cordyceps and its primary products was successfully established. Chinese cordyceps could be precisely identified by detecting an internal transcribed spacer amplicon from O. sinensis and a cytochrome oxidase c subunit 1 amplicon from the host species, at a limit of detection as low as 32 pg. Eleven commercial samples were purchased and successfully tested to further verify that the developed duplex PCR method could be reliably used to identify Chinese cordyceps. It provides a new simple way to discern true commercial Chinese cordyceps from counterfeits in the marketplace. This is an important step toward achieving an authentication method for this Chinese medicine. The methodology and the developmental strategy can be used to authenticate other traditional Chinese medicinal materials.

Evaluation of the FilmArray Blood Culture Identification Panel on Detection of Pathogenic Microorganisms in Positive Blood Cultures: the First Clinical Report in Japan.

FilmArray (FA) is a multiplex PCR-based desktop microbial detection system. The blood culture identification (BCID) panel is an adaptable panel for FA, which diagnoses sepsis and/or systemic infections by detecting 14 bacterial species, 4 bacterial genera, 1 bacterial family, 5 yeast species, and 3 antimicrobial resistance genes (mecA, Klebsiella pneumoniae carbapenemase [KPC], and vanA/B) in positive blood cultures within 1 h. We retrospectively evaluated the FA-BCID panel using 54 positive blood cultures, in which 57 bacterial and 3 yeast strains were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The FA-BCID panel revealed 59 microorganisms in 53 samples; this performance was similar to that of MALDI-TOF MS analysis; however, 1 bacterium in 1 sample was not detected. In addition, mecA genes were detected in 12 Staphylococcus species, which all manifested methicillin resistance in susceptibility testing, whereas genes KPC and vanA/B were not detected, in agreement with the results of antimicrobial susceptibility testing. Although more information on antimicrobial resistance, including activity of IMP-metallo-ß-lactamases, is required in Japan, the FA-BCID panel can detect pathogenic microorganisms in positive blood cultures rapidly, and this method could be beneficial for proper treatment of sepsis and/or systemic infections, especially in small hospitals.

eFG: an electronic resource for Fusarium graminearum.

Fusarium graminearum is a plant pathogen, which causes crop diseases and further leads to huge economic damage worldwide in past decades. Recently, the accumulation of different types of molecular data provides insights into the pathogenic mechanism of F. graminearum, and might help develop efficient strategies to combat this destructive fungus. Unfortunately, most available molecular data related to F. graminearum are distributed in various media, where each single source only provides limited information on the complex biological systems of the fungus. In this work, we present a comprehensive database, namely eFG (Electronic resource for Fusarium graminearum), to the community for further understanding this destructive pathogen. In particular, a large amount of functional genomics data generated by our group is deposited in eFG, including protein subcellular localizations, protein-protein interactions and orthologous genes in other model organisms. This valuable knowledge can not only help to disclose the molecular underpinnings of pathogenesis of the destructive fungus F. graminearum but also help the community to develop efficient strategies to combat this pathogen. To our best knowledge, eFG is the most comprehensive functional genomics database for F. graminearum until now. The eFG database is freely accessible at http://csb.shu.edu.cn/efg/ with a user-friendly and interactive interface, and all data can be downloaded freely. DATABASE URL: http://csb.shu.edu.cn/efg/

Comparative assessment of fungal cellobiohydrolase I richness and composition in cDNA generated using oligo(dT) primers or random hexamers.

Understanding soil fungal distribution and activities, particularly at the level of gene expression, is important in unveiling mechanisms regulating their activities in situ. Recent identification of fungal genes involved in carbon cycling has provided the foundation for developing reverse-transcriptase PCR assays to monitor spatiotemporal gene expression patterns in soils and other complex microbial systems. The polyadenylated 3' ends of eukaryotic mRNA transcripts enables the use of oligo(dT) primers for cDNA synthesis, but this can result in the overrepresentation of the 3' end of transcripts in cDNA pools. In an effort to increase the uniformity of transcripts represented in cDNA pools, random hexamers have been used. The use of both priming methods is abundant in the literature, but we do not know how these methods perform relative to each other. We performed comparative richness and compositional analyses of the fungal glycosyl hydrolase family 7 cellobiohydrolase I gene cbhI amplified from soil cDNAs that had been generated using either oligo(dT) primers or random hexamers. Our results demonstrate that similar cbhI richness and composition were recovered using both approaches. Richness estimates and compositional profiles of cbhI sequence libraries generated from random hexamer-primed cDNA were more variable than from libraries generated from oligo(dT) primed cDNA. However, our overall results indicate that, on average, comparable richness and composition were recovered from soil cDNAs when either priming method was used.

Assessment of inactivating stop codon mutations in forty Saccharomyces cerevisiae strains: implications for [PSI] prion- mediated phenotypes.

The yeast prion [PSI(+)] has been implicated in the generation of novel phenotypes by a mechanism involving a reduction in translation fidelity causing readthrough of naturally occurring stop codons. Some [PSI(+)] associated phenotypes may also be generated due to readthrough of inactivating stop codon mutations (ISCMs). Using next generation sequencing we have sequenced the genomes of two Saccharomyces cerevisiae strains that are commonly used for the study of the yeast [PSI(+)] prion. We have identified approximately 26,000 and 6,500 single nucleotide polymorphisms (SNPs) in strains 74-D694 and G600 respectively, compared to reference strain S288C. In addition to SNPs that produce non-synonymous amino acid changes we have also identified a number of SNPs that cause potential ISCMs in these strains, one of which we show is associated with a [PSI(+)]-dependent stress resistance phenotype in strain G600. We identified twenty-two potential ISCMs in strain 74-D694, present in genes involved in a variety of cellular processes including nitrogen metabolism, signal transduction and oxidative stress response. The presence of ISCMs in a subset of these genes provides possible explanations for previously identified [PSI(+)]-associated phenotypes in this strain. A comparison of ISCMs in strains G600 and 74-D694 with S. cerevisiae strains sequenced as part of the Saccharomyces Genome Resequencing Project (SGRP) shows much variation in the generation of strain-specific ISCMs and suggests this process is possible under complex genetic control. Additionally we have identified a major difference in the abilities of strains G600 and 74-D694 to grow at elevated temperatures. However, this difference appears unrelated to novel SNPs identified in strain 74-D694 present in proteins involved in the heat shock response, but may be attributed to other SNP differences in genes previously identified as playing a role in high temperature growth.

Elucidation of functional markers from Aspergillus nidulans developmental regulator FlbB and their phylogenetic distribution.

Aspergillus nidulans is a filamentous fungus widely used as a model for biotechnological and clinical research. It is also used as a platform for the study of basic eukaryotic developmental processes. Previous studies identified and partially characterized a set of proteins controlling cellular transformations in this ascomycete. Among these proteins, the bZip type transcription factor FlbB is a key regulator of reproduction, stress responses and cell-death. Our aim here was the prediction, through various bioinformatic methods, of key functional residues and motifs within FlbB in order to inform the design of future laboratory experiments and further the understanding of the molecular mechanisms that control fungal development. A dataset of FlbB orthologs and those of its key interaction partner FlbE was assembled from 40 members of the Pezizomycotina. Unique features were identified in each of the three structural domains of FlbB. The N-terminal region encoded a bZip transcription factor domain with a novel histidine-containing DNA binding motif while the dimerization determinants exhibited two distinct profiles that segregated by class. The C-terminal region of FlbB showed high similarity with the AP-1 family of stress response regulators but with variable patterns of conserved cysteines that segregated by class and order. Motif conservation analysis revealed that nine FlbB orthologs belonging to the Eurotiales order contained a motif in the central region that could mediate interaction with FlbE. The key residues and motifs identified here provide a basis for the design of follow-up experimental investigations. Additionally, the presence or absence of these residues and motifs among the FlbB orthologs could help explain the differences in the developmental programs among fungal species as well as define putative complementation groups that could serve to extend known functional characterizations to other species.

Information processing in the transcriptional regulatory network of yeast: functional robustness.

BACKGROUND: Gene networks are considered to represent various aspects of molecular biological systems meaningfully because they naturally provide a systems perspective of molecular interactions. In this respect, the functional understanding of the transcriptional regulatory network is considered as key to elucidate the functional organization of an organism. RESULTS: In this paper we study the functional robustness of the transcriptional regulatory network of S. cerevisiae. We model the information processing in the network as a first order Markov chain and study the influence of single gene perturbations on the global, asymptotic communication among genes. Modification in the communication is measured by an information theoretic measure allowing to predict genes that are 'fragile' with respect to single gene knockouts. Our results demonstrate that the predicted set of fragile genes contains a statistically significant enrichment of so called essential genes that are experimentally found to be necessary to ensure vital yeast. Further, a structural analysis of the transcriptional regulatory network reveals that there are significant differences between fragile genes, hub genes and genes with a high betweenness centrality value. CONCLUSION: Our study does not only demonstrate that a combination of graph theoretical, information theoretical and statistical methods leads to meaningful biological results but also that such methods allow to study information processing in gene networks instead of just their structural properties.

A guild of 45 CRISPR-associated (Cas) protein families and multiple CRISPR/Cas subtypes exist in prokaryotic genomes.

Clustered regularly interspaced short palindromic repeats (CRISPRs) are a family of DNA direct repeats found in many prokaryotic genomes. Repeats of 21-37 bp typically show weak dyad symmetry and are separated by regularly sized, nonrepetitive spacer sequences. Four CRISPR-associated (Cas) protein families, designated Cas1 to Cas4, are strictly associated with CRISPR elements and always occur near a repeat cluster. Some spacers originate from mobile genetic elements and are thought to confer "immunity" against the elements that harbor these sequences. In the present study, we have systematically investigated uncharacterized proteins encoded in the vicinity of these CRISPRs and found many additional protein families that are strictly associated with CRISPR loci across multiple prokaryotic species. Multiple sequence alignments and hidden Markov models have been built for 45 Cas protein families. These models identify family members with high sensitivity and selectivity and classify key regulators of development, DevR and DevS, in Myxococcus xanthus as Cas proteins. These identifications show that CRISPR/cas gene regions can be quite large, with up to 20 different, tandem-arranged cas genes next to a repeat cluster or filling the region between two repeat clusters. Distinctive subsets of the collection of Cas proteins recur in phylogenetically distant species and correlate with characteristic repeat periodicity. The analyses presented here support initial proposals of mobility of these units, along with the likelihood that loci of different subtypes interact with one another as well as with host cell defensive, replicative, and regulatory systems. It is evident from this analysis that CRISPR/cas loci are larger, more complex, and more heterogeneous than previously appreciated.

POSaM: a fast, flexible, open-source, inkjet oligonucleotide synthesizer and microarrayer.

DNA arrays are valuable tools in molecular biology laboratories. Their rapid acceptance was aided by the release of plans for a pin-spotting microarrayer by researchers at Stanford. Inkjet microarraying is a flexible, complementary technique that allows the synthesis of arrays of any oligonucleotide sequences de novo. We describe here an open-source inkjet arrayer capable of rapidly producing sets of unique 9,800-feature arrays.

Functional genomic hypothesis generation and experimentation by a robot scientist.

The question of whether it is possible to automate the scientific process is of both great theoretical interest and increasing practical importance because, in many scientific areas, data are being generated much faster than they can be effectively analysed. We describe a physically implemented robotic system that applies techniques from artificial intelligence to carry out cycles of scientific experimentation. The system automatically originates hypotheses to explain observations, devises experiments to test these hypotheses, physically runs the experiments using a laboratory robot, interprets the results to falsify hypotheses inconsistent with the data, and then repeats the cycle. Here we apply the system to the determination of gene function using deletion mutants of yeast (Saccharomyces cerevisiae) and auxotrophic growth experiments. We built and tested a detailed logical model (involving genes, proteins and metabolites) of the aromatic amino acid synthesis pathway. In biological experiments that automatically reconstruct parts of this model, we show that an intelligent experiment selection strategy is competitive with human performance and significantly outperforms, with a cost decrease of 3-fold and 100-fold (respectively), both cheapest and random-experiment selection.

Identification of the coding region of Saccharomyces cerevisiae chromosome VI using the computer program GenMark.

We searched the nucleotide sequence of budding yeast Saccharomyces cerevisiae chromosome VI (270 kb) for candidate coding regions, using the computer program GenMark. One hundred and twenty-nine putative genes were identified, which is almost the same as the number of ORFs on this chromosome. Nineteen new putative genes were identified through the GenMark analysis. Most large ORFs were also correctly identified (87% of the predicted putative genes identified by the GenMark (110 of 127) matched the reported ORFs). The new coding regions were mostly small but they were distinguished from the more than 2000 ORFs identified by Genetyx. GenMark did not predict 17 ORFs that were over 300 bp long. As these ORFs include known genes, their sequence context may differ somewhat from that of typical yeast genes. These analyses revealed the high potential of GenMark to identify putative genes from numerous short ORFs and will produce information on the likelihood of their being actual genes.

Specificity of the yeast rev3 delta antimutator and REV3 dependency of the mutator resulting from a defect (rad1 delta) in nucleotide excision repair.

The yeast REV3 gene has been predicted to encode a DNA polymerase specializing in translesion synthesis. This polymerase likely participates in spontaneous mutagenesis, as rev3 mutants have an antimutator phenotype. Translesion synthesis also may be necessary for the mutator caused by a RAD1 (nucleotide excision repair) deletion (rad1 delta). To further examine the role of REV3 in spontaneous mutagenesis, we characterized SUP4-o mutations that arose spontaneously in strains having combinations of normal or mutant REV3 and RAD1 alleles. The largest fraction of the rev3 delta-dependent mutation rate decrease was observed for single base-pair substitutions and deletions, although the rates of all mutational classes detected in the RAD1 background were reduced by at least 30%. Interestingly, inactivation of REV3 was associated with a doubling of the number of sites at which the retrotransposon Ty inserted. rev3 delta also greatly diminished the magnitude of the rad1 delta mutator, but not to the rev3 delta antimutator level, implicating REV3-dependent and independent processes in the rad1 delta mutator effect. However, the specificity of the rev3 delta antimutator suggested that the same REV3-dependent processes gave rise to the majority of spontaneous mutations in the RAD1 and rad1 delta strains.