Species Delimitation and Description of Mesocriconema nebraskense n. sp. (Nematoda: Criconematidae), a Morphologically Cryptic, Parthenogenetic Species from North American Grasslands.

Nematode surveys of North American grasslands conducted from 2010 to 2015 frequently recovered a species of criconematid nematode morphologically resembling Mesocriconema curvatum. These specimens were recovered from remnant native prairies in the central tallgrass ecoregion of North America, and not from surrounding agroecosystems. Historical records indicate that M. curvatum is a cosmopolitan species feeding on a wide range of agronomic and native plants. DNA barcoding indicates North American grasslands contain at least 10 phylogenetically distinct lineages of Mesocriconema that resemble, but are not, M. curvatum. Analysis of the two most common lineages reveals two distinctly different population structures. The variation in population structure suggests unique evolutionary histories associated with their diversification. These two major lineages share a sympatric distribution and their slight morphological differences contrast with a high level of genetic separation. Based on their genetic divergence, fixed diagnostic nucleotides, population structure, species delimitation metrics, and a sympatric distribution, we believe that one of these distinct lineages warrants formal nomenclatural recognition. Herein, we provide formal recognition for Mesocriconema nebraskense n. sp. and discuss its relationship to other Mesocriconema lineages discovered in native North American grasslands.

A Review of the Impact of the COVID-19 Pandemic on Colorectal Cancer Screening: Implications and Solutions.

The COVID-19 pandemic has impacted all aspects of medical care, including cancer screening and preventative measures. Colorectal cancer screening declined significantly at the onset of the pandemic as the result of an intentional effort to conserve resources, prioritize emergencies and reduce risk of transmission. There has already been an increase in diagnosis at more advanced stages and symptomatic emergencies due to suspended screenings. As endoscopy units find their way back to pre-pandemic practices, a backlog of cases remains. The missed CRC diagnoses amongst the missed screenings carry a risk of increased morbidity and mortality which will only increase as time-to-diagnosis grows. This review discusses the impact of COVID-19 on colonoscopy screening rates, trends in stages/symptoms/circumstances at diagnosis, and economic and social impact of delayed diagnosis. Triaging and use of FITs are proposed solutions to the challenge of catching up with the large number of pandemic-driven missed CRC screenings.

Coordinated regulation of transcription by CcpA and the Staphylococcus aureus two-component system HptRS.

The success of Staphylococcus aureus as a pathogen is due in part to its ability to adapt to changing environmental conditions using signal transduction pathways, such as metabolite- responsive regulators and two-component systems. S. aureus has a two-component system encoded by the gene pair sav0224 (hptS) and sav0223 (hptR) that regulate the hexose phosphate transport (uhpT) system in response to extracellular glucose-6-phosphate. Glycolytic intermediates such as glucose-6-phosphate are important carbon sources that also modulate the activity of the global metabolite-responsive transcriptional regulator CcpA. Because uhpT has a putative CcpA binding site in its promoter and it is regulated by HptR, it was hypothesized the regulons of CcpA and HptR might intersect. To determine if the regulatory domains of CcpA and HptRS overlap, ccpA was deleted in strains SA564 and SA564-ΔhptRS and growth, metabolic, proteomic, and transcriptional differences were assessed. As expected, CcpA represses hptS and hptR in a glucose dependent manner; however, upon CcpA derepression, the HptRS system functions as a transcriptional activator of metabolic genes within the CcpA regulon. Importantly, inactivation of ccpA and hptRS altered sensitivity to fosfomycin and ampicillin in the absence of exogenous glucose-6-phosphate, indicating that both CcpA and HptRS modulate antibiotic susceptibility.

The design of wrinkled microcapsules for enhancement of release rate.

Thermally expandable microcapsules (TEMs) with wrinkled shells are prepared by one-step suspension polymerization, allowing for encapsulation and controlled release of cargos. Wrinkling results from concurrent crosslinking of shell copolymers and vaporization of volatile reagents along with density increase upon polymerization. Through control of the vapor pressure of the reagents and systematic variation of the suspension composition, microcapsules with different degrees of wrinkling are prepared, ranging from locally dimpled to highly crumpled morphologies. The corresponding increase of the surface-to-volume ratio results in increasing release rate of encapsulated oil red dye as a model cargo. As such, in addition to shell thickness and radius, the wrinkleness provides an effective control parameter for adjusting the release rate. The wrinkled microcapsules with a large surface-to-volume ratio may find applications in drug delivery, chemicals scavenging, and self-healing materials.