Biology subjects

Rhodes, S.

Publications and source records attributed to Rhodes, S..

4 recordsLinked to original sources

bioRxiv2022

Antimicrobial copper as an effective and practical deterrent to surface transmission of SARS-CoV-2

The aerosols are critical for SARS-CoV-2 transmission, however in areas with high confluence of people the contaminated surfaces take an important role that we could attack using antimicrobial surfaces including copper. In this study, we wanted to challenge infectious SARS-CoV-2 with two samples of copper surfaces and one plastic surface as control at different direct times contact. To evaluate and quantify virucidal activity of copper against SARS-CoV-2, two methods of experimental infection were performed, TCID50 and plaque assays on VeroE6 cells, showing significant inactivation of high titer of SARS-CoV-2 within minutes reaching 99.9 % of inactivation of infectivity on both copper surfaces. Daily high demand surfaces contamination is an issue that we have to worry about not only during the actual pandemic time but also for future, where copper or its alloys will have a pivotal role. ImportanceQuantitative data obtained of TCID50 and plaque assay with infectious SARS-CoV-2 virus showed that after direct contact with copper or copper alloys, viruses were inactivated within minutes. Notably, the SARS-CoV-2 virus used in these assays was in high titer (106 PFU/mL) showing strong copper inactivation of the infectious SARS-CoV-2.

microbiology↗

bioRxiv2022

Ancient DNA reveals interstadials as a driver of the common vole population dynamics during the last glacial period

1AimThe common vole is a temperate rodent widespread across Europe. It was also one of the most abundant small mammal species throughout the Late Pleistocene. Phylogeographic studies of its extant populations suggested the Last Glacial Maximum (LGM, 26.5-19 ka ago) as one of the main drivers of the species population dynamics. However, analyses based solely on extant genetic diversity may not recover the full complexity of past population history. The main aim of this study was to investigate the evolutionary history and identify the main drivers of the common vole population dynamics during the Late Pleistocene. LocationEurope TaxonCommon vole (Microtus arvalis) MethodsWe generated a dataset comprising 4.2 kb-long fragment of mitochondrial DNA from 148 ancient and 51 modern specimens sampled from multiple localities across Europe and covering the last 60 thousand years (ka). We used Bayesian inference to reconstruct their phylogenetic relationships and to estimate the age of specimens that were not directly dated. ResultsWe estimate the time to the most recent common ancestor of all Last Glacial and extant common vole lineages to 90 ka ago and the divergence of the main mtDNA lineages present in extant populations to between 55 and 40 ka ago, earlier than previous estimates. We find multiple lineage turnovers in Europe in the period of high climate variability at the end of Marine Isotope Stage 3 (MIS 3; 57-29 ka ago) in addition to those found previously around the Pleistocene/Holocene transition. Conversely, data from the Western Carpathians suggest continuity throughout the LGM even at high latitudes. Main conclusionsOur results suggest that the main factor affecting the common vole populations during the last glacial period was the reduction of open habitats during the interstadial periods while the climate deterioration during the LGM had little impact on species population dynamics.

evolutionary biology↗

bioRxiv2022

Interphotoreceptor matrix proteoglycans IMPG1 and IMPG2 proteolyze in the SEA domain and reveal localization mutual dependency

The interphotoreceptor matrix (IPM) is a specialized extracellular mesh of molecules surrounding the inner and outer segments of photoreceptor neurons. Interphotoreceptor matrix proteoglycan 1 and 2 (IMPG1 and IMPG2) are major components of the IPM. Both proteoglycans possess SEA (sperm protein, enterokinase and agrin) domains, which may support proteolysis. Interestingly mutations in the SEA domains of IMPG1 and IMPG2 are associated with vision disease in humans. However, if SEA domains in IMPG molecules undergo proteolysis, and how this contributes to vision pathology is unknown. Therefore, we investigated SEA-mediated proteolysis of IMPG1 and IMPG2 and its significance to IPM physiology. Immunoblot analysis confirmed proteolysis of IMPG1 and IMPG2 in the retinas of wildtype mice. Point mutations mimicking human mutations in the SEA domain of IMPG1 that are associated with vision disease inhibited proteolysis. These findings demonstrate that proteolysis is part of the maturation of IMPG1 and IMPG2, in which deficits are associated with vision diseases. Further, immunohistochemical assays showed that proteolysis of IMPG2 generated two subunits, a membrane-attached peptide and an extracellular peptide. Notably, the extracellular portion of IMPG2 trafficked from the IPM around the inner segment toward the outer segment IPM by an IMPG1-dependent mechanism. This result provides the first evidence of a trafficking system that shuttles IMPG1 and IMPG2 from the inner to outer IPM in a co-dependent manner. In addition, these results suggest an interaction between IMPG1-IMPG2, and propose that mutations affecting one IMPG could affect the localization of the normal IMPG partner contributing to the disease mechanism of vision diseases associated with defective IMPG molecules.

molecular biology↗

bioRxiv2022

The 13A4 monoclonal antibody to the mouse PROM1 protein recognizes a structural epitope

PurposeWe endeavored to map the epitope of the rat monoclonal antibody mAB 13A4 to the mouse PROM1 (CD133, AC133) protein. mAB 13A4 is the main reagent used to detect the mouse PROM1 protein. PROM1 is required for the maintenance of primary cilia and mutations in the Prom1 gene are associated with retinal degeneration. MethodsEpitope tagged clones of splice variants and tiled deletion mutants were used to map the mAB 13A4 epitope and test the predicted tertiary structure of PROM1. The proteins were expressed in Neuro 2a cells and analyzed by Western blot with antibodies to PROM1 and the epitope tag. ResultsDeletions in the second and third extracellular domains of the PROM1 protein disrupted the mAB 13A4 epitope. Furthermore, the affinity of mAB 13A4 to the major PROM1 isoform in photoreceptor cells is significantly reduced due to the inclusion of a photoreceptor-specific alternative exon in the third extracellular domain. Interestingly, a deletion in the photoreceptor specific isoform of six amino acids adjacent to the alternative exon restored the affinity of mAB 13A4 to PROM1. ConclusionmAB 13A4 recognizes a structural epitope that is stabilized by two of the extracellular domains of PROM1. The results of our mutagenesis are consistent with the computationally predicted helical bundle structure of PROM1 and point to the utility of mAB 13A4 for evaluating the effect of mutations on the PROM1 structure. We show that the PROM1 isoform composition needs to be considered when interpreting tissue and developmental expression data produced by mAB 13A4.

immunology↗