Development of a bead-based multiplexed PCR assay for the simultaneous detection of multiple Mycoplasma species

We describe the development and analytical validation of a specific and sensitive 7-plex polymerase chain reaction assay coupled to a bead-based liquid suspension array for high throughput detection of multiple Mycoplasma spp. of ruminants. The assay employs a combination of newly designed and previously validated primer-probe sets that target genetic loci specific for Mycoplasma bovis, Mycoplasma mycoides cluster, Mycoplasma mycoides subsp. mycoides SC (MmmSC) and Mycoplasma capricolum subspecies capripneumoniae (Mccp). PCR products were hybridized to specific oligonucleotide probes bound to spectrally unique, 5.6 µm diameter, carboxylated beads, and subsequently analyzed by flow cytometry. Analytical sensitivity for the targeted Mycoplasma species ranged from 10 fg to 1 pg of purified gDNA extracted from broth cultures (approximately 8-800 MmmSC genome equivalents). In silico comparison of primers and probes, and analytical assessment with a range of near-neighbor Mycoplasma species and multiple bacterial respiratory pathogens of ruminants demonstrated 100% analytical specificity of the assay. To assess assay performance and diagnostic specificity, 192 bovine respiratory samples were analyzed by incorporating a high throughput DNA extraction platform. The assay correctly classified all 192 field samples as negative for MmmSC or Mccp with an apparent 100% diagnostic specificity for these pathogens. 33/192 field samples were positive for M. bovis and all were confirmed by PCR or sequence verification of the uvrC gene. The results from this study indicate that the bead-based liquid suspension array will provide a reliable, analytically sensitive and specific platform to simultaneously interrogate ruminant respiratory samples for multiple Mycoplasma species, including Mycoplasma mycoides cluster organisms exotic to the United States. Sequential addition of primer-probe sets to the assay did not significantly impact analytical sensitivity of individual primer-probe combinations, suggesting that expanding the array to include more Mycoplasma species will not compromise overall performance

Disseminated Bovine viral diarrhea virus in a persistently infected alpaca (Vicugna pacos) cria

Bovine viral diarrhea virus (BVDV) is an emerging infectious pathogen of concern to the alpaca industry. A 4-month-old, intact, male alpaca cria was diagnosed as persistently infected with BVDV on the basis of repeated positive antemortem polymerase chain reaction (PCR) and virus isolation (VI) assays and negative serologic titers to BVDV. Immunohistochemistry, real-time reverse transcription PCR, and VI performed on tissues collected at necropsy demonstrated disseminated BVDV-1b infection. Virus was detected in multiple tissues, including parotid salivary gland, testes, prostate, kidneys, skin, and gastrointestinal tract. Demonstration of BVDV in previously unreported tissues suggests additional potential routes of BVDV transmission in alpacas

Disseminated Bovine Viral Diarrhea Virus

Bovine viral diarrhea virus (BVDV) is an emerging infectious pathogen of concern to the alpaca industry. A 4-month-old, intact, male alpaca cria was diagnosed as persistently infected with BVDV on the basis of repeated positive antemortem polymerase chain reaction (PCR) and virus isolation (VI) assays and negative serologic titers to BVDV. Immunohistochemistry, real-time reverse transcription PCR, and VI performed on tissues collected at necropsy demonstrated disseminated BVDV-1b infection. Virus was detected in multiple tissues, including parotid salivary gland, testes, prostate, kidneys, skin, and gastrointestinal tract. Demonstration of BVDV in previously unreported tissues suggests additional potential routes of BVDV transmission in alpacas

Melting phase relations in the Fe-S and Fe-S-O systems at core conditions in small terrestrial bodies

We report an experimental investigation of phase equilibria in the Fe-S and Fe-S-O systems. Experiments were performed at high temperatures (1400–1850°C) and high pressures (14 and 20 GPa) using a multi-anvil apparatus. The results of this study are used to understand the effect of sulfur and oxygen on core dynamics in small terrestrial bodies. We observe that the formation of solid FeO grains occurs at the Fe-S liquid – Fe solid interface at high temperature ( > 1400°C at 20 GPa). Oxygen fugacities calculated for each O-bearing sample show that redox conditions vary from ΔIW = −0.65 to 0. Considering the relative density of each phase and existing evolutionary models of terrestrial cores, we apply our experimental results to the cores of Mars and Ganymede. We suggest that the presence of FeO in small terrestrial bodies tends to contribute to outer-core compositional stratification. Depending on the redox and thermal history of the planet, FeO may also help form a transitional redox zone at the core-mantle boundary

Asteroid (101955) Bennu in the laboratory: Properties of the sample collected by OSIRIS ‐ REx

On September 24, 2023, NASA's OSIRIS‐REx mission dropped a capsule to Earth containing ~120 g of pristine carbonaceous regolith from Bennu. We describe the delivery and initial allocation of this asteroid sample and introduce its bulk physical, chemical, and mineralogical properties from early analyses. The regolith is very dark overall, with higher‐reflectance inclusions and particles interspersed. Particle sizes range from submicron dust to a stone ~3.5 cm long. Millimeter‐scale and larger stones typically have hummocky or angular morphologies. Some stones appear mottled by brighter material that occurs as veins and crusts. Hummocky stones have the lowest densities and mottled stones have the highest. Remote sensing of Bennu's surface detected hydrated phyllosilicates, magnetite, organic compounds, carbonates, and scarce anhydrous silicates, all of which the sample confirms. We also find sulfides, presolar grains, and, less expectedly, Mg,Na‐rich phosphates, as well as other trace phases. The sample's composition and mineralogy indicate substantial aqueous alteration and resemble those of Ryugu and the most chemically primitive, low‐petrologic‐type carbonaceous chondrites. Nevertheless, we find distinct hydrogen, nitrogen, and oxygen isotopic compositions, and some of the material we analyzed is enriched in fluid‐mobile elements. Our findings underscore the value of sample return—especially for low‐density material that may not readily survive atmospheric entry—and lay the groundwork for more comprehensive analyses