Multiplexed Metagenomic Deep Sequencing To Analyze the Composition of High-Priority Pathogen Reagents.

Laboratories studying high-priority pathogens need comprehensive methods to confirm microbial species and strains while also detecting contamination. Metagenomic deep sequencing (MDS) inventories nucleic acids present in laboratory stocks, providing an unbiased assessment of pathogen identity, the extent of genomic variation, and the presence of contaminants. Double-stranded cDNA MDS libraries were constructed from RNA extracted from in vitro-passaged stocks of six viruses (La Crosse virus, Ebola virus, canine distemper virus, measles virus, human respiratory syncytial virus, and vesicular stomatitis virus). Each library was dual indexed and pooled for sequencing. A custom bioinformatics pipeline determined the organisms present in each sample in a blinded fashion. Single nucleotide variant (SNV) analysis identified viral isolates. We confirmed that (i) each sample contained the expected microbe, (ii) dual indexing of the samples minimized false assignments of individual sequences, (iii) multiple viral and bacterial contaminants were present, and (iv) SNV analysis of the viral genomes allowed precise identification of the viral isolates. MDS can be multiplexed to allow simultaneous and unbiased interrogation of mixed microbial cultures and (i) confirm pathogen identity, (ii) characterize the extent of genomic variation, (iii) confirm the cell line used for virus propagation, and (iv) assess for contaminating microbes. These assessments ensure the true composition of these high-priority reagents and generate a comprehensive database of microbial genomes studied in each facility. MDS can serve as an integral part of a pathogen-tracking program which in turn will enhance sample security and increase experimental rigor and precision. IMPORTANCE Both the integrity and reproducibility of experiments using select agents depend in large part on unbiased validation to ensure the correct identity and purity of the species in question. Metagenomic deep sequencing (MDS) provides the required level of validation by allowing for an unbiased and comprehensive assessment of all the microbes in a laboratory stock

Ebola virus, but not Marburg virus, replicates efficiently and without required adaptation in snake cells.

Ebola virus (EBOV) disease is a viral hemorrhagic fever with a high case-fatality rate in humans. This disease is caused by four members of the filoviral genus Ebolavirus, including EBOV. The natural hosts reservoirs of ebolaviruses remain to be identified. Glycoprotein 2 of reptarenaviruses, known to infect only boa constrictors and pythons, is similar in sequence and structure to ebolaviral glycoprotein 2, suggesting that EBOV may be able to infect reptilian cells. Therefore, we serially passaged EBOV and a distantly related filovirus, Marburg virus (MARV), in boa constrictor JK cells and characterized viral infection/replication and mutational frequency by confocal imaging and sequencing. We observed that EBOV efficiently infected and replicated in JK cells, but MARV did not. In contrast to most cell lines, EBOV-infected JK cells did not result in an obvious cytopathic effect. Surprisingly, genomic characterization of serial-passaged EBOV in JK cells revealed that genomic adaptation was not required for infection. Deep sequencing coverage (>10,000×) demonstrated the existence of only a single nonsynonymous variant (EBOV glycoprotein precursor pre-GP T544I) of unknown significance within the viral population that exhibited a shift in frequency of at least 10 per cent over six serial passages. In summary, we present the first reptilian cell line that replicates a filovirus at high titers, and for the first time demonstrate a filovirus genus-specific restriction to MARV in a cell line. Our data suggest the possibility that there may be differences between the natural host spectra of ebolaviruses and marburgviruses

Ebola virus, but not Marburg virus, replicates efficiently and without required adaptation in snake cells.

Ebola virus (EBOV) disease is a viral hemorrhagic fever with a high case-fatality rate in humans. This disease is caused by four members of the filoviral genus Ebolavirus, including EBOV. The natural hosts reservoirs of ebolaviruses remain to be identified. Glycoprotein 2 of reptarenaviruses, known to infect only boa constrictors and pythons, is similar in sequence and structure to ebolaviral glycoprotein 2, suggesting that EBOV may be able to infect reptilian cells. Therefore, we serially passaged EBOV and a distantly related filovirus, Marburg virus (MARV), in boa constrictor JK cells and characterized viral infection/replication and mutational frequency by confocal imaging and sequencing. We observed that EBOV efficiently infected and replicated in JK cells, but MARV did not. In contrast to most cell lines, EBOV-infected JK cells did not result in an obvious cytopathic effect. Surprisingly, genomic characterization of serial-passaged EBOV in JK cells revealed that genomic adaptation was not required for infection. Deep sequencing coverage (>10,000×) demonstrated the existence of only a single nonsynonymous variant (EBOV glycoprotein precursor pre-GP T544I) of unknown significance within the viral population that exhibited a shift in frequency of at least 10 per cent over six serial passages. In summary, we present the first reptilian cell line that replicates a filovirus at high titers, and for the first time demonstrate a filovirus genus-specific restriction to MARV in a cell line. Our data suggest the possibility that there may be differences between the natural host spectra of ebolaviruses and marburgviruses

A fixed moderate-dose combination of tiletamine+zolazepam outperforms midazolam in induction of short-term immobilization of ball pythons (Python regius).

Laboratory animals are commonly anesthetized to prevent pain and distress and to provide safe handling. Anesthesia procedures are well-developed for common laboratory mammals, but not as well established in reptiles. We assessed the performance of intramuscularly injected tiletamine (dissociative anesthetic) and zolazepam (benzodiazepine sedative) in fixed combination (2 mg/kg and 3 mg/kg) in comparison to 2 mg/kg of midazolam (benzodiazepine sedative) in ball pythons (Python regius). We measured heart and respiratory rates and quantified induction parameters (i.e., time to loss of righting reflex, time to loss of withdrawal reflex) and recovery parameters (i.e., time to regain righting reflex, withdrawal reflex, normal behavior). Mild decreases in heart and respiratory rates (median decrease of <10 beats per minute and <5 breaths per minute) were observed for most time points among all three anesthetic dose groups. No statistically significant difference between the median time to loss of righting reflex was observed among animals of any group (p = 0.783). However, the withdrawal reflex was lost in all snakes receiving 3mg/kg of tiletamine+zolazepam but not in all animals of the other two groups (p = 0.0004). In addition, the time for animals to regain the righting reflex and resume normal behavior was longer in the drug combination dose groups compared to the midazolam group (p = 0.0055). Our results indicate that midazolam is an adequate sedative for ball pythons but does not suffice to achieve reliable immobilization or anesthesia, whereas tiletamine+zolazepam achieves short-term anesthesia in a dose-dependent manner

Libraries and sequencing generated for <i>Camptotheca acuminata</i>.

1<p>Libraries used in the first, initial de novo assembly.</p>2<p>Libraries only sequenced for expression abundance estimates, reads were not included in de novo assembly.</p>3<p>Libraries used in the second, final de novo assembly.</p><p>M: Million.</p

Monoterpene indole alkaloid pathway.

<p>The key intermediate strictosidine is formed by condensation of tryptamine, which contributes the indole ring, and secologanin, which is produced from the monoterpene geraniol. In various plants, strictosidine is further metabolized to generate over 2,500 monoterpene indole alkaloids. Solid lines indicate single enzymatic steps; dashed lines indicate multiple steps.</p

Expression patterns of known genes in monoterpene indole alkaloid biosynthesis across different tissues and treatments.

<p>Expression values in log₂ FPKM (fragments per Kilobase of transcript per million fragments mapped) were calculated, negative values were set to zero and then were clustered using R <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0052506#pone.0052506-R1" target="_blank">[39]</a>. A) <i>Catharanthus roseus</i>: Expression values were sorted in three major groups: Developmental tissues, Yeast extract (YE) treatment of suspension cells (SC), and Methyl jasmonate (MJ) treatment of sterile seedlings (SS) and hairy roots (HR). B) <i>Rauvolfia serpentina</i>. Expression values shown represent the different developmental tissues.</p

Libraries and sequencing generated for <i>Rauvolfia serpentin</i>a.

<p>M: Million.</p

Summary of statistics of the transcriptome de novo assemblies of <i>Camptotheca acuminata</i>, <i>Catharanthus roseus</i>, and <i>Rauvolfia serpentina</i>.

<p>Summary of statistics of the transcriptome de novo assemblies of <i>Camptotheca acuminata</i>, <i>Catharanthus roseus</i>, and <i>Rauvolfia serpentina</i>.</p