Risk of symptomatic COVID-19 due to aircraft transmission: a retrospective cohort study of contact-traced flights during England's containment phase.

BACKGROUND: Knowledge gaps remain regarding SARS-CoV-2 transmission on flights. We conducted a retrospective cohort study to estimate risk of acquiring symptomatic SARS-CoV-2 on aircraft, to inform contact tracing and infection control efforts. METHODS: We identified co-passengers of infectious passengers on 18 England-bound flights from European cities up to 12/03/2020, using manifests received for contact tracing. Infectious passengers were laboratory-confirmed cases with symptom onset from 7 days before to 2 days after the flight. Possible aircraft-acquired cases were laboratory-confirmed with onset 3-14 days post-flight with no known non-flight exposure. Manifests was merged with the national case management dataset (identifying cases, onset dates, contact tracing status) and the national COVID-19 linelist. Contact tracing notes were reviewed to identify non-flight exposures. We calculated attack rates (ARs) among all co-passengers and within subgroups, including by distance from infectious cases and number of infectious cases on-board. RESULTS: There were 55 infectious passengers and 2313 co-passengers, including 2221 flight-only contacts. Five possible aircraft-acquired cases were identified; ARs of 0.2% (95%CI 0.1-0.5) among all flight-only contacts and 3.8% (95%CI 1.3-10.6) among contact-traced flight-only contacts sat within a two-seat radius. The AR among 92 co-travellers with known non-flight exposure to infectious cases was 13.0% (95%CI 7.6%-21.4%). There were insufficient numbers to assess differences between subgroups. CONCLUSION: We conclude that risk of symptomatic COVID-19 due to transmission on short to medium-haul flights is low, and recommend prioritising contact-tracing of close contacts and co-travellers where resources are limited. Further research on risk on aircraft is encouraged

The yeast P5 type ATPase, Spf1, regulates manganese transport into the endoplasmic reticulum

The endoplasmic reticulum (ER) is a large, multifunctional and essential organelle. Despite intense research, the function of more than a third of ER proteins remains unknown even in the well-studied model organism Saccharomyces cerevisiae. One such protein is Spf1, which is a highly conserved, ER localized, putative P-type ATPase. Deletion of SPF1 causes a wide variety of phenotypes including severe ER stress suggesting that this protein is essential for the normal function of the ER. The closest homologue of Spf1 is the vacuolar P-type ATPase Ypk9 that influences Mn2+ homeostasis. However in vitro reconstitution assays with Spf1 have not yielded insight into its transport specificity. Here we took an in vivo approach to detect the direct and indirect effects of deleting SPF1. We found a specific reduction in the luminal concentration of Mn2+ in ∆spf1 cells and an increase following it’s overexpression. In agreement with the observed loss of luminal Mn2+ we could observe concurrent reduction in many Mn2+-related process in the ER lumen. Conversely, cytosolic Mn2+-dependent processes were increased. Together, these data support a role for Spf1p in Mn2+ transport in the cell. We also demonstrate that the human sequence homologue, ATP13A1, is a functionally conserved orthologue. Since ATP13A1 is highly expressed in developing neuronal tissues and in the brain, this should help in the study of Mn2+-dependent neurological disorders

Molecular and Neuroimaging Findings in Pontocerebellar Hypoplasia Type 2 (PCH2): Is Prenatal Diagnosis Possible?

The pontocerebellar hypoplasias (PCH) are a group of early-onset, autosomal recessive disorders resulting in abnormal growth and function of the brainstem and cerebellum. PCH type 2 (PCH2) is characterized by respiratory and feeding difficulties at birth, extrapyramidal dyskinesia, severe developmental impairment, progressive microcephaly and frequent death in childhood. Neuropathologic findings include diffuse cerebral gliosis with white matter changes, hypoplastic pons with depletion of neurons in the pontine nuclei, hypoplastic cerebellar hemispheres due to short cerebellar folia with poor branching, segmental loss of dentate, inferior olivary, and ventral pontine nuclei, and near absence of transverse pontine fibers with preservation of long fiber tracts and spinal anterior horn cells. On brain imaging, the cerebellar hemispheres appear very flat, and are more severely involved than the vermis. Most patients with PCH2 have mutations in TSEN54, with occasional mutations found in TSEN34 or TSEN2, genes that encode subunits of tRNA splicing endonuclease. Although this is a congenital disorder of pontocerebellar dysgenesis with fetal onset of neurodegeneration and symptoms at birth, prenatal imaging is unreliable in diagnosing this disorder in utero. We report on IVF dizygous twins with detailed prenatal imaging that failed to reveal any cerebellar abnormalities. Direct sequence analysis of TSEN54 showed homozygosity for c.919G>T, the common founder mutation in most PCH2 patients, and both parents were heterozygous for this mutation. We found no evidence of cerebellar dysgenesis on prenatal ultrasounds, but MRI tractography showed absence of pontine crossing fibers, a unique feature that might be useful for prenatal diagnosis of this condition. (C) 2010 Wiley-Liss, In

MBLinhibitors.com, a Website Resource Offering Information and Expertise for the Continued Development of Metallo-β-Lactamase Inhibitors

In an effort to facilitate the discovery of new, improved inhibitors of the metallo-β-lactamases (MBLs), a new, interactive website called MBLinhibitors.com was developed. Despite considerable efforts from the science community, there are no clinical inhibitors of the MBLs, which are now produced by human pathogens. The website, MBLinhibitors.com, contains a searchable database of known MBL inhibitors, and inhibitors can be searched by chemical name, chemical formula, chemical structure, Simplified Molecular-Input Line-Entry System (SMILES) format, and by the MBL on which studies were conducted. The site will also highlight a “MBL Inhibitor of the Month”, and researchers are invited to submit compounds for this feature. Importantly, MBLinhibitors.com was designed to encourage collaboration, and researchers are invited to submit their new compounds, using the “Submit” function on the site, as well as their expertise using the “Collaboration” function. The intention is for this site to be interactive, and the site will be improved in the future as researchers use the site and suggest improvements. It is hoped that MBLinhibitors.com will serve as the one-stop site for any important information on MBL inhibitors and will aid in the discovery of a clinically useful MBL inhibitor

Spf1 affects the exit of GPI anchor proteins from the ER.

<p>WT and ∆<i>spf1</i> cells expressing tagged GPI anchored proteins (YFP-Ccw14 and RFP-Gas1) were imaged. While these proteins are normally localized to the cell periphery and the vacuole, a deletion of SPF1 enhances ER retention. Scale bar: 5µm. </p

Biosynthesis of sphingolipids is interrupted due to deletion of SPF1.

<p>(<b>A</b>) WT and Δ<i>spf1</i> cells were plated in serial dilution on YPD plates without and with Aureobasidin A, an IPC synthase inhibitor. Loss of SPF1 increases the sensitivity to this inhibitor. (<b>B</b>) The levels of different types of IPC, were measured by mass spectrometry and are mostly lower in Δ<i>spf1</i> cells compared to WT. (<b>C</b>) The levels of different types of MIPC and M(IP)2C, were measured by mass spectrometry and are mostly lower in Δ<i>spf1</i> cells compared to WT. * P value<0.05, ** P value<0.01, *** P value<0.001. </p

Δ<i>spf1</i> cells are more sensitive to the ergosterol biosynthesis inhibitor Terbinafine and display change in ergosterol distribution compared to WT.

<p>(<b>A</b>) WT and Δ<i>spf1</i> cells were plated in serial dilution on YPD plates without and with Terbinafine, an ergosterol biosynthesis inhibitor. Loss of SPF1 causes growth inhibition in the presence of this inhibitor. (<b>B</b>) WT and Δ<i>spf1</i> cells were stained for sterol distribution by fillipin staining. While most of the Δ<i>spf1</i> cells exhibit homogeneous sterol distribution, the WT shows a non-homogenous sterol staining pattern. Scale bar: 5µm.</p

ATP13A1 is the functional homologue of Spf1.

<p>(<b>A</b>) Immunostaining of HeLa cells with α-ATP13A1 and DAPI (nucleus staining) indicates perinuclear localization for ATP13A1. Scale bar: 10µm. (<b>B</b>) Amount of spliced XBP1 (a result of ER stress) was assayed by qPCR analysis. Silencing of ATP13A1 in HeLa cells causes an increase in the spliced form. (<b>C</b>) Western blot of BiP protein reveals that its amount is increased upon silencing of ATP13A1 in HeLa cells. Blot was also probed with an antibody against GAPDH as a loading control. (<b>D</b>) Mass Spectrometry analysis reveals a specific increase in GlcCer levels in cells silenced for ATP13A1 suggesting enhanced activity of GlcCer synthase. (<b>E</b>) Fluorescent cholera toxin subunit B (CT-B) was used to stain the plasma membrane ganglioside GM1. Cells treated with an siRNA against ATP13A1 display accumulation of GM1. Scale bar: 10µm.</p

Spf1 affects protein mannosylation and its ATPase activity is required for its molecular function.

<div><p>(A) Western blot of three GPI anchored proteins that undergo known mannosylation (Gas1, Ccw14 and Yps1) reveals that this modification is reduced in Δ<i>spf1</i> compared to WT. </p> <p>(B) Western blot of Gas1 in WT and Δ<i>spf1</i> cells without any plasmid, with a plasmid containing full-length SPF1 gene, or with plasmid containing the full-length gene carrying a mutation rendering the protein ATPase-dead. Lack of rescue in the ATPase dead mutant confirms that the reason for the defect in Gas1 maturation is the absence of the functional ATPase activity of Spf1. </p></div