Measuring SARS-CoV-2 RNA concentrations in neighborhood wastewater.

Longitudinal wastewater sampling during the COVID-19 pandemic was an important aspect of disease surveillance, adding to a more complete understanding of infection dynamics and providing important data for community public health monitoring and intervention planning. This was largely accomplished by testing SARS-CoV-2 RNA concentrations in samples from municipal wastewater treatment plants (WWTPs). We evaluated the utility of testing for virus levels upstream from WWTP within the residential neighborhoods that feed into the WWTP. We propose that monitoring virus dynamics across residential neighborhoods could reveal important public health-relevant information about community sub-group heterogeneity in virus concentrations. PRINCIPAL RESULTS: Virus concentration patterns display heterogeneity within neighborhoods and between neighborhoods over time. Sewage SARS-CoV-2 RNA concentrations as measured by RT-qPCR also corresponded closely to verified COVID-19 infection counts within individual neighborhoods. More importantly, our data suggest the loss of disease-relevant public health information when sampling occurs only at the level of WWTP instead of upstream in neighborhoods. Spikes in SARS-CoV-2 RNA concentrations in neighborhoods are often masked by dilution from other neighborhoods in the WWTP samples. MAJOR CONCLUSIONS: Wastewater-based epidemiology (WBE) employed at WWTP reliably detects SARS-CoV-2 in a city-sized population but provides less actionable public health information about neighborhoods experiencing greater viral infection and disease. Neighborhood sewershed sampling reveals important population-based information about local virus dynamics and improves opportunities for public health intervention. Longitudinally employed, neighborhood sewershed surveillance may provide a 3-6 day early warning of SARS-CoV-2 infection spikes and, importantly, highly specific information on subpopulations in a community particularly at higher risk at different points in time. Sampling in neighborhoods may thus provide timely and cost-saving information for targeted interventions within communities.

Smartphone-based multiplex 30-minute nucleic acid test of live virus from nasal swab extract.

Rapid, sensitive and specific detection and reporting of infectious pathogens is important for patient management and epidemic surveillance. We demonstrated a point-of-care system integrated with a smartphone for detecting live virus from nasal swab media, using a panel of equine respiratory infectious diseases as a model system for corresponding human diseases such as COVID-19. Specific nucleic acid sequences of five pathogens were amplified by loop-mediated isothermal amplification on a microfluidic chip and detected at the end of reactions by the smartphone. Pathogen-spiked horse nasal swab samples were correctly diagnosed using our system, with a limit of detection comparable to that of the traditional lab-based test, polymerase chain reaction, with results achieved in ∼30 minutes.

Mobile Platform for Multiplexed Detection and Differentiation of Disease-Specific Nucleic Acid Sequences, Using Microfluidic Loop-Mediated Isothermal Amplification and Smartphone Detection.

New tools are needed to enable rapid detection, identification, and reporting of infectious viral and microbial pathogens in a wide variety of point-of-care applications that impact human and animal health. We report the design, construction, and characterization of a platform for multiplexed analysis of disease-specific DNA sequences that utilizes a smartphone camera as the sensor in conjunction with a hand-held "cradle" that interfaces the phone with a silicon-based microfluidic chip embedded within a credit-card-sized cartridge. Utilizing specific nucleic acid sequences for four equine respiratory pathogens as representative examples, we demonstrated the ability of the system to utilize a single 15 µL droplet of test sample to perform selective positive/negative determination of target sequences, including integrated experimental controls, in approximately 30 min. Our approach utilizes loop-mediated isothermal amplification (LAMP) reagents predeposited into distinct lanes of the microfluidic chip, which when exposed to target nucleic acid sequences from the test sample, generates fluorescent products that when excited by appropriately selected light emitting diodes (LEDs), are visualized and automatically analyzed by a software application running on the smartphone microprocessor. The system achieves detection limits comparable to those obtained by laboratory-based methods and instruments. Assay information is combined with the information from the cartridge and the patient to populate a cloud-based database for epidemiological reporting of test results.

Oxytocin opposes effects of bacterial endotoxin on ER-stress signaling in Caco2BB gut cells.

BACKGROUND: The neuropeptide neuromodulator and hormone oxytocin (OT) activates signaling pathways involved in mRNA translation in response to endoplasmic reticulum stress and reduces inflammation associated with experimental colitis in rats. The anti-inflammatory effects of OT may serve a vital role in the development, survival and function of newborn-type enterocytes during microbial gut colonization, which coincides with the milk suckling period when OT receptor expression peaks in the gut. Furthermore, mice deficient in the OT receptor have abnormal gut structure and function, underscoring OT's developmental importance. METHODS: We tested the effect of OT upon lipopolysaccharide (LPS)-induced markers of the inflammatory response in Caco2BB gut cells in vitro using automated immunocapillary electrophoresis. RESULTS: We demonstrate that OT suppresses NF-κB signaling and presumably inflammatory transcriptional programs, which are unleashed by LPS through the modulation of IκB. We show that OT counteracts LPS-elicited silencing of the unfolded protein response, a pathway limiting endoplasmic reticulum stress by suppressing protein translation. OT selectively activates dsRNA-activated kinase (PKR), X-box binding protein 1 (XBP1), immunoglobulin binding protein (BiP), A20 (TNFα-induced protein 3) and inositol requiring enzyme 1a (IRE1a). OT inactivates eukaryotic translation initiation factor 2a (eIF2a) without significant activation of protein kinase RNA-like endoplasmic reticulum kinase (PERK). CONCLUSIONS: Mild, preemptive stimulation of endoplasmic reticulum stress sensors by OT may precondition newborn enterocytes to resist apoptosis associated with inflammation and may support their differentiation and development by modulating cellular metabolism. GENERAL SIGNIFICANCE: OT may protect enterocytes and other cell types, such as neurons, from stress-related complications during postnatal development.

Building Infectious Disease Research Programs to Promote Security and Enhance Collaborations with Countries of the Former Soviet Union.

Addressing the threat of infectious diseases, whether natural, the results of a laboratory accident, or a deliberate act of bioterrorism, requires no corner of the world be ignored. The mobility of infectious agents and their rapid adaptability, whether to climate change or socioeconomic drivers or both, demand the science employed to understand these processes be advanced and tailored to a country or a region, but with a global vision. In many parts of the world, largely because of economic struggles, scientific capacity has not kept pace with the need to accomplish this goal and has left these regions and hence the world vulnerable to infectious disease outbreaks. To build scientific capability in a developing region requires cooperation and participation of experienced international scientists who understand the issues and are committed to educate the next generations of young investigators in the region. These efforts need to be coupled with the understanding and resolve of local governments and international agencies to promote an aggressive science agenda. International collaborative scientific investigation of infectious diseases not only adds significantly to scientific knowledge, but it promotes health security, international trust, and long-term economic benefit to the region involved. This premise is based on the observation that the most powerful human inspiration is that which brings peoples together to work on and solve important global challenges. The republics of the former Soviet Union provide a valuable case study for the need to rebuild scientific capacity as they are located at the crossroads where many of the world's great epidemics began. The scientific infrastructure and disease surveillance capabilities of the region suffered significant decline after the breakup of the Soviet Union. The U.S. Cooperative Threat Reduction (CTR) Program, a part of the U.S. Department of Defense, together with partner countries, have worked diligently to improve the capabilities in this region to guard against the potential future risk from especially dangerous pathogens. The dissolution of the Soviet Union left behind many scientists still working to study pathogens using antiquated protocols in unsafe laboratories. To address this situation, the CTR program began improving laboratory infrastructure, establishing biosafety and biosecurity programs, and training scientists in modern techniques, with emphasis on biosurveillance and safe containment of especially dangerous pathogens. In the Republic of Georgia, this effort culminated in the construction of a modern containment laboratory, the Richard G. Lugar Center for Public Health Research in Tbilisi to house both isolated especially dangerous pathogens as well as the research to be conducted on these agents. The need now is to utilize and sustain the investment made by CTR by establishing strong public and animal health science programs in these facilities tailored to the needs of the region and the goals for which this investment was made. A similar effort is ongoing in other former Soviet Republics. Here, we provide the analysis and recommendations of an international panel of expert scientists appointed by the Cooperative Biological Engagement Program of the Defense Threat Reduction Agency to provide advice to the stakeholders on the scientific path for the future. The emphasis is on an implementation strategy for decision makers and scientists to consider providing a sustainable biological science program in support of the One Health initiative. Opportunities, potential barriers, and lessons learned while meeting the needs of the Republic of Georgia and the Caucasus region are discussed. It is hoped that this effort will serve as a model for similar scientific needs in not only the former Soviet Union republics but also other regions challenged by infectious diseases where the CTR program operates.

Pathosphere.org: pathogen detection and characterization through a web-based, open source informatics platform.

BACKGROUND: The detection of pathogens in complex sample backgrounds has been revolutionized by wide access to next-generation sequencing (NGS) platforms. However, analytical methods to support NGS platforms are not as uniformly available. Pathosphere (found at Pathosphere.org) is a cloud - based open - sourced community tool that allows for communication, collaboration and sharing of NGS analytical tools and data amongst scientists working in academia, industry and government. The architecture allows for users to upload data and run available bioinformatics pipelines without the need for onsite processing hardware or technical support. RESULTS: The pathogen detection capabilities hosted on Pathosphere were tested by analyzing pathogen-containing samples sequenced by NGS with both spiked human samples as well as human and zoonotic host backgrounds. Pathosphere analytical pipelines developed by Edgewood Chemical Biological Center (ECBC) identified spiked pathogens within a common sample analyzed by 454, Ion Torrent, and Illumina sequencing platforms. ECBC pipelines also correctly identified pathogens in human samples containing arenavirus in addition to animal samples containing flavivirus and coronavirus. These analytical methods were limited in the detection of sequences with limited homology to previous annotations within NCBI databases, such as parvovirus. Utilizing the pipeline-hosting adaptability of Pathosphere, the analytical suite was supplemented by analytical pipelines designed by the United States Army Medical Research Insititute of Infectious Diseases and Walter Reed Army Institute of Research (USAMRIID-WRAIR). These pipelines were implemented and detected parvovirus sequence in the sample that the ECBC iterative analysis previously failed to identify. CONCLUSIONS: By accurately detecting pathogens in a variety of samples, this work demonstrates the utility of Pathosphere and provides a platform for utilizing, modifying and creating pipelines for a variety of NGS technologies developed to detect pathogens in complex sample backgrounds. These results serve as an exhibition for the existing pipelines and web-based interface of Pathosphere as well as the plug-in adaptability that allows for integration of newer NGS analytical software as it becomes available.

Andes hantavirus variant in rodents, southern Amazon Basin, Peru.

We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted.

Oxytocin modulates markers of the unfolded protein response in Caco2BB gut cells.

We have shown that oxytocin receptor (OTR) expression in neonatal rat enterocytes is robust from birth to weaning, but OTR function during this period is unknown. We previously reported that oxytocin (OT) stimulation of Caco2BB cells (enterocytes in vitro) inhibits the mammalian target of rapamycin complex 1 (mTORC1) signaling. The unfolded protein response (UPR) is known to protectively reduce translation during endoplasmic reticulum (ER) stress. Because the mTORC1 pathway is linked to cellular stress, we investigated markers of UPR in OT-stimulated Caco2BB cells. We report that OT modulates several factors involved in sensing and translation of ER stress. High OT (62.5 nM) reduced translation initiation factor 4E-BP1 phosphorylation (Ser65), which is known to inhibit cap-dependent translation via its rate-limiting eukaryotic translation initiation factor 4E (eIF4E). Importantly, high OT increased phosphorylation of eukaryotic translation initiation factor 2a (eIF2a) phospho-Ser51, which inhibits eIF2a. High OT also increased protein kinase RNA-like endoplasmic reticulum kinase phosphorylation, a sensor of ER stress and a kinase of eIF2a. Both high and low OT activated inositol requiring enzyme1 (IRE1), which generates the transcription factor X-box binding protein 1 (XBP1) and induces the UPR. We also show that OT modulates XBP1 splicing and induces tribbles 3 (TRIB3; a negative regulator of Akt and protein involved in autophagy) and immunoglobulin binding protein (BiP; ER-chaperone). Taken together, these results indicate that OT modulates sensors of ER stress and autophagy. These findings support our hypothesis that transiently elevated OTR expression in neonatal gut may serve a protective function during a critical postnatal developmental period.

OGA: an ontological tool of human phenotypes with genetic associations.

BACKGROUND: The availability of genetic data has increased dramatically in recent years. The greatest value of this data is its potential for personalized medicine. Many new associations are reported every day from Genome Wide Association Studies (GWAS). However, robust, reproducible associations are elusive for some complex diseases. Ontologies present a potential way to distinguish between spurious associations and those with a potential influence on the phenotype. Such an approach would be based on finding associations of the same genetic variant with closely related, but distinct, phenotypes. This approach can be accomplished with a phenotype ontology that also holds genetic association data. RESULTS: Here, we report a structured knowledge application to navigate and to facilitate the discovery of relationships between different phenotypes and their genetic associations. CONCLUSIONS: OGA allows users to (1) find the intersecting set of genes for phenotypes of interest, (2) find empirical p values for such observations and (3) OGA outperforms similar applications in number of total concepts and genes mapped.

Oxytocin modulates mTORC1 pathway in the gut.

Our recent findings of a weaning-related pattern of oxytocin (OT) and OT receptor (OTR) expression in the rat enteric nervous system and in villus-crypt enterocytes, together with the known high level and stability of OT in breast milk support that OT may play a role in gut function and development. We previously described a biphasic dose-response of the PI3K/Akt pathway in gut cells treated with OT. Activation peaked at 62.5 nM OT (30 min) and coincided with OTR internalization. Here we use automated Western blotting to further explore OT-elicited changes in Akt and pAkt(T308), as well as in downstream substrates p70 S6 kinase-1 (S6K1) and eIF-4E binding protein 1 (4E-BP1). Relative to fresh growth medium (FGM) alone, our results showed OT in FGM reduced the abundance and phosphorylation of S6K1 and the phosphorylation of 4E-BP1, both substrates of mammalian target of rapamycin complex 1 (mTORC1). Phosphorylation of mTORC1 regulator, Raptor(S792), was increased by high and low OT concentrations, with predicted inhibitory effects on mTORC1. OT thus downregulates anabolic effects induced by FGM activity catalyzed by mTORC1. OT is a regulator of the PI3K/Akt/mTORC1 pathway in Caco2BB cells and may modulate translation in gut cells.

Genomic analysis of two novel human enterovirus C genotypes found in respiratory samples from Peru.

We report the discovery of two enteroviruses detected in nasopharyngeal samples obtained from subjects with respiratory disease in Peru. Phylogenetic analysis indicated that both viruses belong to a clade within the species Human enterovirus C, which includes the recently characterized human enteroviruses 109 and 104. Members of this clade have undergone significant genomic rearrangement, as indicated by deletions in the hypervariable region of the 5' UTR and the VP1 protein, as well as recombination within the non-structural genes. Our findings and review of published sequences suggests that several novel human enterovirus C serotypes are currently circulating worldwide.

Identification of a highly transmissible animal-independent Staphylococcus aureus ST398 clone with distinct genomic and cell adhesion properties.

UNLABELLED: A methicillin-resistant Staphylococcus aureus (MRSA) clone known as ST398 has emerged as a major cause of acute infections in individuals who have close contact with livestock. More recently, the emergence of an animal-independent ST398 methicillin-sensitive S. aureus (MSSA) clone has been documented in several countries. However, the limited surveillance of MSSA has precluded an accurate assessment of the global spread of ST398 and its clinical relevance. Here we provide evidence that ST398 is a frequent source of MSSA infections in northern Manhattan and is readily transmitted between individuals in households. This contrasts with the limited transmissibility of livestock-associated ST398 (LA-ST398) MRSA strains between humans. Our whole-genome sequence analysis revealed that the chromosome of the human-associated ST398 MSSA clone is smaller than that of the LA-ST398 MRSA reference strain S0385, due mainly to fewer mobile genetic elements (MGEs). In contrast, human ST398 MSSA isolates harbored the prophage ϕ3 and the human-specific immune evasion cluster (IEC) genes chp and scn. While most of the core genome was conserved between the human ST398 MSSA clone and S0385, these strains differed substantially in their repertoire and composition of intact adhesion genes. These genetic changes were associated with significantly enhanced adhesion of human ST398 MSSA isolates to human skin keratinocytes and keratin. We propose that the human ST398 MSSA clone can spread independent of animal contact using an optimized repertoire of MGEs and adhesion molecules adapted to transmission among humans. IMPORTANCE: Staphylococcus aureus strains have generally been considered to be species specific. However, cross-species transfers of S. aureus clones, such as ST398 methicillin-resistant S. aureus (MRSA), from swine to humans have been reported. Recently, we observed the emergence of ST398 methicillin-susceptible S. aureus (MSSA) as a colonizing strain of humans in northern Manhattan. Here we report that ST398 is a frequent cause of MSSA infections in this urban setting. The ST398 MSSA clone was readily transmitted within households, independent of animal contact. We discovered that human ST398 MSSA genomes were smaller than that of the LA-ST398 strain S0385 due to fewer mobile genetic elements. Human and LA-ST398 strains also differed in their composition of adhesion genes and their ability to bind to human skin keratinocytes, providing a potential mechanism of S. aureus host adaptation. Our findings illustrate the importance of implementing molecular surveillance of MSSA given the evidence for the rapid and clinically undetected spread of ST398 MSSA.

Impaired carbohydrate digestion and transport and mucosal dysbiosis in the intestines of children with autism and gastrointestinal disturbances.

Gastrointestinal disturbances are commonly reported in children with autism, complicate clinical management, and may contribute to behavioral impairment. Reports of deficiencies in disaccharidase enzymatic activity and of beneficial responses to probiotic and dietary therapies led us to survey gene expression and the mucoepithelial microbiota in intestinal biopsies from children with autism and gastrointestinal disease and children with gastrointestinal disease alone. Ileal transcripts encoding disaccharidases and hexose transporters were deficient in children with autism, indicating impairment of the primary pathway for carbohydrate digestion and transport in enterocytes. Deficient expression of these enzymes and transporters was associated with expression of the intestinal transcription factor, CDX2. Metagenomic analysis of intestinal bacteria revealed compositional dysbiosis manifest as decreases in Bacteroidetes, increases in the ratio of Firmicutes to Bacteroidetes, and increases in Betaproteobacteria. Expression levels of disaccharidases and transporters were associated with the abundance of affected bacterial phylotypes. These results indicate a relationship between human intestinal gene expression and bacterial community structure and may provide insights into the pathophysiology of gastrointestinal disturbances in children with autism.

Breast milk contains relevant neurotrophic factors and cytokines for enteric nervous system development.

Breast-feeding plays an important role for the development of the newborn. Non-breast fed premature born infants show a significantly higher risk of developing diseases like infantile diarrhoea and necrotizing enterocolitis. In this study, the content of neurotrophic factors and cytokines, which might influence the postnatal development of the enteric nervous system (ENS), was determined in human breast milk. Glial cell-line-derived neurotrophic factor (GDNF), ciliary neurotrophic factor (CNTF) as well as a panel of cytokines were analyzed using single factor or multiplex ELISA. In order to link their presence in milk with possible effects on the development of the ENS, rat myenteric neurons were cultured in protein extracts from breast milk. Neurite outgrowth, neuron survival and nestin expression in glial cells were measured. Growth factors and cytokines were found in all breast milk samples at varying concentrations. It could be demonstrated that protein extracts of breast milk increased the amount of surviving enteric neurones as well as neurite outgrowth. Additionally it was shown, that the number of nestin and S100-expressing glial cells increased significantly after incubating in breast milk protein extracts. The data suggest that milk-born proteins support the development of the enteric nervous system.

Characterization of a canine homolog of hepatitis C virus.

An estimated 3% of the world's population is chronically infected with hepatitis C virus (HCV). Although HCV was discovered more than 20 y ago, its origin remains obscure largely because no closely related animal virus homolog has been identified; furthermore, efforts to understand HCV pathogenesis have been hampered by the absence of animal models other than chimpanzees for human disease. Here we report the identification in domestic dogs of a nonprimate hepacivirus. Comparative phylogenetic analysis of the canine hepacivirus (CHV) confirmed it to be the most genetically similar animal virus homolog of HCV. Bayesian Markov chains Monte Carlo and associated time to most recent common ancestor analyses suggest a mean recent divergence time of CHV and HCV clades within the past 500-1,000 y, well after the domestication of canines. The discovery of CHV may provide new insights into the origin and evolution of HCV and a tractable model system with which to probe the pathogenesis, prevention, and treatment of diseases caused by hepacivirus infection.

Novel picornavirus in Turkey poults with hepatitis, California, USA.

To identify a candidate etiologic agent for turkey viral hepatitis, we analyzed samples from diseased turkey poults from 8 commercial flocks in California, USA, that were collected during 2008-2010. High-throughput pyrosequencing of RNA from livers of poults with turkey viral hepatitis (TVH) revealed picornavirus sequences. Subsequent cloning of the ≈9-kb genome showed an organization similar to that of picornaviruses with conservation of motifs within the P1, P2, and P3 genome regions, but also unique features, including a 1.2-kb sequence of unknown function at the junction of P1 and P2 regions. Real-time PCR confirmed viral RNA in liver, bile, intestine, serum, and cloacal swab specimens from diseased poults. Analysis of liver by in situ hybridization with viral probes and immunohistochemical testing of serum demonstrated viral nucleic acid and protein in livers of diseased poults. Molecular, anatomic, and immunologic evidence suggests that TVH is caused by a novel picornavirus, tentatively named turkey hepatitis virus.

Molecular characterization of severe and mild cases of influenza A (H1N1) 2009 strain from Argentina.

While worldwide pandemic influenza A(H1N1) pdm case fatality rate (CFR) was 0.4%, Argentina's was 4.5%. A total of 34 strains from mild and severe cases were analyzed. A full genome sequencing was carried out on 26 of these, and a partial sequencing on the remaining eight. We observed no evidence that the high CFR can be attributed to direct virus changes. No evidence of re-assortment, mutations associated with resistance to antiviral drugs, or genetic drift that might contribute to virulence was observed. Although the mutation D225G associated with severity in the latest reports from the Ukraine and Norway is not observed among the Argentine strains, an amino acid change in the area (S206T) surrounding the HA receptor binding domain was observed, the same previously established worldwide.

Molecular characterization of severe and mild cases of influenza A (H1N1) 2009 strain from Argentina / Caracterización molecular de cepas de influenza A (H1N1) 2009 de casos leves y graves de la Argentina

While worldwide pandemic influenza A(H1N1) pdm case fatality rate (CFR) was 0.4%, Argentina's was 4.5%. A total of 34 strains from mild and severe cases were analyzed. A full genome sequencing was carried out on 26 of these, and a partial sequencing on the remaining eight. We observed no evidence that the high CFR can be attributed to direct virus changes. No evidence of re-assortment, mutations associated with resistance to antiviral drugs, or genetic drift that might contribute to virulence was observed. Although the mutation D225G associated with severity in the latest reports from the Ukraine and Norway is not observed among the Argentine strains, an amino acid change in the area (S206T) surrounding the HA receptor binding domain was observed, the same previously established worldwide.

Mientras que la tasa de letalidad (CFR) para (H1N1)pdm en todo el mundo era del 0.4%, en la Argentina la mortalidad observada fue de 4.5%. La secuenciación del genoma completo de 26 cepas de virus argentinos de influenza A (H1N1)pdm de casos leves y graves y de 8 cepas secuenciadas parcialmente no mostró evidencia de que la elevada tasa de letalidad se pueda atribuir directamente a cambios en el virus. No se encontraron hallazgos de recombinación, de mutaciones asociadas con la resistencia a los medicamentos antivirales ni de variaciones genéticas que puedan contribuir a la virulencia observada. Si bien la mutación D225G asociada con la gravedad, comunicada en informes procedentes de Ucrania y Noruega, no se ha encontrado en las cepas argentinas estudiadas, se ha observado un cambio aminoacídico en la región (S206T) en torno al dominio del sitio de unión al receptor en la HA, el mismo hallado en cepas distribuidas alrededor del mundo.

Heart and skeletal muscle inflammation of farmed salmon is associated with infection with a novel reovirus.

Atlantic salmon (Salmo salar L.) mariculture has been associated with epidemics of infectious diseases that threaten not only local production, but also wild fish coming into close proximity to marine pens and fish escaping from them. Heart and skeletal muscle inflammation (HSMI) is a frequently fatal disease of farmed Atlantic salmon. First recognized in one farm in Norway in 1999, HSMI was subsequently implicated in outbreaks in other farms in Norway and the United Kingdom. Although pathology and disease transmission studies indicated an infectious basis, efforts to identify an agent were unsuccessful. Here we provide evidence that HSMI is associated with infection with piscine reovirus (PRV). PRV is a novel reovirus identified by unbiased high throughput DNA sequencing and a bioinformatics program focused on nucleotide frequency as well as sequence alignment and motif analyses. Formal implication of PRV in HSMI will require isolation in cell culture and fulfillment of Koch's postulates, or prevention or modification of disease through use of specific drugs or vaccines. Nonetheless, as our data indicate that a causal relationship is plausible, measures must be taken to control PRV not only because it threatens domestic salmon production but also due to the potential for transmission to wild salmon populations.

Arabidopsis deadenylases AtCAF1a and AtCAF1b play overlapping and distinct roles in mediating environmental stress responses.

To maintain homeostasis in an ever-changing environment organisms have evolved mechanisms to reprogram gene expression. One central mechanism regulating gene expression is messenger RNA (mRNA) degradation, which is initiated by poly(A) tail shortening (deadenylation). The carbon catabolite repressor 4-CCR4 associated factor1 (CCR4-CAF1) complex is the major enzyme complex that catalyzes mRNA deadenylation and is conserved among eukaryotes. However, the components and functions of this global regulatory complex have not been well characterized in plants. Here we investigate the CAF1 family in Arabidopsis (Arabidopsis thaliana). We identify 11 AtCAF1 homologs and show that a subset of these genes are responsive to mechanical wounding, among them are AtCAF1a and AtCAF1b whose expression levels are rapidly and transiently induced by wounding. The differential expression profiles of the various AtCAF1s suggest that not all AtCAF1 genes are involved in stress-responsive regulation of transcript levels. Comparison of misexpressed genes identified via transcript profiling of Atcaf1a and Atcaf1b mutants at different time points before and after wounding suggests that AtCAF1a and AtCAF1b target shared and unique transcripts for deadenylation with temporal specificity. Consistent with the AtPI4Kgamma3 transcript exhibiting the largest increase in abundance in Atcaf1b, AtCAF1b targets AtPI4Kgamma3 mRNA for deadenylation. Stress-tolerance assays demonstrate that AtCAF1a and AtCAF1b are involved in mediating abiotic stress responses. However, AtCAF1a and AtCAF1b are not functionally redundant in all cases, nor are they essential for all environmental stresses. These findings demonstrate that these closely related proteins exhibit overlapping and distinct roles with respect to mRNA deadenylation and mediation of stress responses.