Biology subjects

Nguyen, T.-Q.

Publications and source records attributed to Nguyen, T.-Q..

4 recordsLinked to original sources

bioRxiv2024

Experimental reproduction of viral replication and disease in dairy calves and lactating cows inoculated with highly pathogenic avian influenza H5N1 clade 2.3.4.4b

Highly pathogenic avian influenza (HPAI) H5N1 of the hemagglutinin clade 2.3.4.4b was detected in the United States in late 2021 and continues to circulate in all four North American flyways to date. In addition to impacting poultry, these HPAI viruses caused mortality events in wild bird species and wild mammals. Transmission in multiple host species raises the concern for mammalian adaptation. On March 25, 2024, HPAI H5N1 clade 2.3.4.4b was confirmed in a dairy cow in Texas in response to a multi-state investigation into milk production losses. Over one hundred positive herds were rapidly identified in Texas and eleven other U.S. states. The case description included reduced feed intake and rumen motility in lactating cows, decreased milk production, and thick yellow milk. The diagnostic investigation revealed detections of viral RNA in milk and mammary tissue with alveolar epithelial degeneration and necrosis, and positive immunoreactivity of glandular epithelium by immunohistochemistry. A single transmission event, likely from avian species to dairy cattle, followed by limited local transmission preceded the onward lateral transmission of H5N1 clade 2.3.4.4b genotype B3.13. We sought to experimentally reproduce infection with genotype B3.13 in Holstein yearling heifers and lactating cows. The heifers were inoculated by an aerosol respiratory route and the cows by an intramammary route. Clinical disease was mild in the heifers, but infection was confirmed by virus detection, lesions, and seroconversion. Clinical disease in lactating cows included decreased rumen motility, changes to milk appearance, and production losses consistent with field reports of viral mastitis. Infection was confirmed by high levels of viral RNA detected in milk, virus isolation, lesions in mammary tissue, and seroconversion. This study provides the foundation to investigate additional routes of infection, transmission, and intervention strategies.

microbiology↗

bioRxiv2024

Emergence and interstate spread of highly pathogenic avian influenza A(H5N1) in dairy cattle

Highly pathogenic avian influenza (HPAI) viruses cross species barriers and have the potential to cause pandemics. In North America, HPAI A(H5N1) viruses related to the goose/Guangdong 2.3.4.4b hemagglutinin phylogenetic clade have infected wild birds, poultry, and mammals. Our genomic analysis and epidemiological investigation showed that a reassortment event in wild bird populations preceded a single wild bird-to-cattle transmission episode. The movement of asymptomatic cattle has likely played a role in the spread of HPAI within the United States dairy herd. Some molecular markers in virus populations were detected at low frequency that may lead to changes in transmission efficiency and phenotype after evolution in dairy cattle. Continued transmission of H5N1 HPAI within dairy cattle increases the risk for infection and subsequent spread of the virus to human populations.

microbiology↗

bioRxiv2020

Nanoscale Chromatin Imaging and Analysis (nano-ChIA) platform bridges 4-D chromatin organization with molecular function

In eukaryotic cells, chromatin structure is linked to transcription processes through the regulation of genome organization. Extending across multiple length-scales - from the nucleosome to higher-order three-dimensional structures - chromatin is a dynamic system which evolves throughout the lifetime of a cell. However, no individual technique can fully elucidate the behavior of chromatin organization and its relation to molecular function at all length- and timescales at both a single-cell and a cell population level. Herein, we present a multi-technique nanoscale Chromatin Imaging and Analysis (nano-ChIA) platform that bridges electron tomography and optical superresolution imaging of chromatin conformation and transcriptional processes, with resolution down to the level of individual nucleosomes, with high-throughput, label-free analysis of chromatin packing and its dynamics in live cells. Utilizing nano-ChIA, we observed that chromatin is localized into spatially separable packing domains, with an average diameter of around 200 nm, sub-Mb genomic size, and an internal fractal structure. The chromatin packing behavior of these domains is directly influenced by active gene transcription. Furthermore, we demonstrated that the chromatin packing domain structure is correlated among progenitor cells and all their progeny, indicating that the organization of chromatin into fractal packing domains is heritable across cell division. Further studies employing the nano-ChIA platform have the potential to provide a more coherent picture of chromatin structure and its relation to molecular function.

genomics↗

bioRxiv2018

Spectral Contrast Optical Coherence Tomography Angiography Enables Single-Scan Vessel Imaging

Optical coherence tomography angiography relies on motion for contrast and requires at least two data acquisitions per pointwise scanning location. We present a method termed spectral contrast optical coherence tomography angiography using visible light that relies on the spectral signatures of blood for angiography from a single scan using endogenous contrast. We demonstrate the molecular sensitivity of this method, which enables lymphatic vessel, blood, and tissue discrimination.

biophysics↗