Astrovirus-Induced Synthesis of Nitric Oxide Contributes to Virus Control during Infection

Astrovirus is one of the major causes of infant and childhood diarrhea worldwide. Our understanding of astrovirus pathogenesis trails behind our knowledge of its molecular and epidemiologic properties. Using a recently developed small-animal model, we investigated the mechanisms by which astrovirus induces diarrhea and the role of both the adaptive and innate immune responses to turkey astrovirus type-2 (TAstV-2) infection. Astrovirus-infected animals were analyzed for changes in total lymphocyte populations, alterations in CD4(+)/CD8(+) ratios, production of virus-specific antibodies (Abs), and macrophage activation. There were no changes in the numbers of circulating or splenic lymphocytes or in CD4(+)/CD8(+) ratios compared to controls. Additionally, there was only a modest production of virus-specific Abs. However, adherent spleen cells from infected animals produced more nitric oxide (NO) in response to ex vivo stimulation with lipopolysaccharide. In vitro analysis demonstrated that TAstV-2 induced macrophage production of inducible nitric oxide synthase. Studies using NO donors and inhibitors in vivo demonstrated, for the first time, that NO inhibited astrovirus replication. These studies suggest that NO is important in limiting astrovirus replication and are the first, to our knowledge, to describe the potential role of innate immunity in astrovirus infection

Genomic Analysis of Closely Related Astroviruses▿

To understand astrovirus biology, it is essential to understand factors associated with its evolution. The current study reports the genomic sequences of nine novel turkey astrovirus (TAstV) type 2-like clinical isolates. This represents, to our knowledge, the largest genomic-length data set available for any one astrovirus type. The comparison of these TAstV sequences suggests that the TAstV species contains multiple subtypes and that recombination events have occurred across the astrovirus genome. In addition, the analysis of the capsid gene demonstrated evidence for both site-specific positive selection and purifying selection

Astrovirus Induces Diarrhea in the Absence of Inflammation and Cell Death

Astroviruses are a leading cause of infantile viral gastroenteritis worldwide. Very little is known about the mechanisms of astrovirus-induced diarrhea. One reason for this is the lack of a small-animal model. Recently, we isolated a novel strain of astrovirus (TAstV-2) from turkeys with the emerging infectious disease poult enteritis mortality syndrome. In the present studies, we demonstrate that TAstV-2 causes growth depression, decreased thymus size, and enteric infection in infected turkeys. Infectious TAstV-2 can be recovered from multiple tissues, including the blood, suggesting that there is a viremic stage during infection. In spite of the severe diarrhea, histopathologic changes in the intestine were mild and there was a surprising lack of inflammation. This may be due to the increased activation of the potent immunosuppressive cytokine transforming growth factor beta during astrovirus infection. These studies suggest that the turkey will be a useful small-animal model with which to study astrovirus pathogenesis and immunity

Development of the Chick Microbiome: How Early Exposure Influences Future Microbial Diversity

The concept of improving animal health through improved gut health has existed in food animal production for decades; however, only recently have we had the tools to identify microbes in the intestine associated with improved performance. Currently, little is known about how the avian microbiome develops or the factors that affect its composition. To begin to address this knowledge gap, the present study assessed the development of the cecal microbiome in chicks from hatch to 28 days of age with and without a live Salmonella vaccine and/or probiotic supplement; both are products intended to promote gut health. The microbiome of growing chicks develops rapidly from days 1-3, and the microbiome is primarily Enterobacteriaceae, but Firmicutes increase in abundance and taxonomic diversity starting around day 7. As the microbiome continues to develop, the influence of the treatments becomes stronger. Predicted metagenomic content suggests that functionally, treatment may stimulate more differences at day 14, despite the strong taxonomic differences at day 28. These results demonstrate that these live microbial treatments do impact the development of the bacterial taxa found in the growing chicks; however, additional experiments are needed to understand the biochemical and functional consequences of these alterations

Science Communication Training Imparts Confidence and Influences Public Engagement Activity

ABSTRACT The impacts of science are felt across all socio-ecological levels, ranging from the individual to societal. In order to adapt or respond to scientific discoveries, novel technologies, or biomedical or environmental challenges, a fundamental understanding of science is necessary. However, antiscientific rhetoric, mistrust in science, and the dissemination of misinformation hinder the promotion of science as a necessary and beneficial component of our world. Scientists can promote scientific literacy by establishing dialogues with nonexperts, but they may find a lack of formal training as a barrier to public engagement. To address this, the American Society for Biochemistry and Molecular Biology (ASBMB) launched the Art of Science Communication course in 2015 in order to provide scientists at all career stages with introductory science communication training. In 2020, we conducted a retrospective survey of former participants to evaluate how the course had impacted participants’ science communication behaviors and their confidence engaging with nonexperts, as well as other benefits to their professional development. We found that scientists were significantly more likely to communicate with nonexpert audiences following the course compared to before (77% versus 51%; P < 0.0001). In addition, quantitative and qualitative data suggested that scientists were more confident in their ability to communicate science after completing the course (median of 8, standard deviation [SD] of 0.98 versus median of 5, SD of 1.57; P < 0.0001). Qualitative responses from participants supported quantitative findings. This suggested that the Art of Science Communication course is highly effective at improving the confidence of scientists to engage with the public and other nonexpert audiences regardless of career status. These data-driven perspectives provide a rationale for the implementation of broadly accessible science communication training programs that promote public engagement with science