Governments around the world must rapidly mobilize and make difficult policy decisions to mitigate the coronavirus disease 2019 (COVID-19) pandemic. Because deaths have been concentrated at older ages, we highlight the important role of demography, particularly, how the age structure of a population may help explain differences in fatality rates...

Type IV filaments (T4F), which are helical assemblies of type IV pilins, constitute a superfamily of filamentous nanomachines virtually ubiquitous in prokaryotes that mediate a wide variety of functions. The competence (Com) pilus is a widespread T4F, mediating DNA uptake (the first step in natural transformation) in bacteria with one membrane (monoderms), an important mechanism of horizontal gene transfer. Here, we report the results of genomic, phylogenetic, and structural analyses of ComGC, the major pilin subunit of Com pili. By performing a global comparative analysis, we show that Com pili genes are virtually ubiquitous in Bacilli, a major monoderm class of Firmicutes. This also revealed that ComGC displays extensive sequence conservation, defining a monophyletic group among type IV pilins. We further report ComGC solution structures from two naturally competent human pathogens, Streptococcus sanguinis (ComGCSS) and Streptococcus pneumoniae (ComGCSP), revealing that this pilin displays extensive structural conservation. Strikingly, ComGCSS and ComGCSP exhibit a novel type IV pilin fold that is purely helical. Results from homology modeling analyses suggest that the unusual structure of ComGC is compatible with helical filament assembly. Because ComGC displays such a widespread distribution, these results have implications for hundreds of monoderm species.

Bacteria accumulate small, organic compounds called compatible solutes via uptake from the environment or biosynthesis from available precursors to maintain the turgor pressure of the cell in response to osmotic stress. The halophile Vibrio parahaemolyticus has biosynthesis pathways for the compatible solutes ectoine (encoded by ectABC-asp_ect) and glycine betaine (encoded by betIBA-proXWV), four betaine-carnitine-choline transporters (encoded by bccT1 to bccT4), and a second ProU transporter (encoded by proVWX). All of these systems are osmotically inducible with the exception of bccT2. Previously, it was shown that CosR, a MarR-type regulator, was a direct repressor of ectABC-asp_ect in Vibrio species. In this study, we investigated whether CosR has a broader role in the osmotic stress response. Expression analyses demonstrated that betIBA-proXWV, bccT1, bccT3, bccT4, and proVWX are repressed in low salinity. Examination of an in-frame cosR deletion mutant showed that expression of these systems is derepressed in the mutant at low salinity compared with the wild type. DNA binding assays demonstrated that purified CosR binds directly to the regulatory region of both biosynthesis systems and four transporters. In Escherichia coli green fluorescent protein (GFP) reporter assays, we demonstrated that CosR directly represses transcription of betIBA-proXWV, bccT3, and proVWX. Similar to Vibrio harveyi, we showed betIBA-proXWV was directly activated by the quorum-sensing LuxR homolog OpaR, suggesting a conserved mechanism of regulation among Vibrio species. Phylogenetic analysis demonstrated that CosR is ancestral to the Vibrionaceae family, and bioinformatics analysis showed widespread distribution among Gammaproteobacteria in general. Incidentally, in Aliivibrio fischeri, Aliivibrio finisterrensis, Aliivibrio sifiae, and Aliivibrio wodanis, an unrelated MarR-type regulator gene named ectR was clustered with ectABC-asp, which suggests the presence of another novel ectoine biosynthesis regulator. Overall, these data show that CosR is a global regulator of osmotic stress response that is widespread among bacteria.

IMPORTANCE Vibrio parahaemolyticus can accumulate compatible solutes via biosynthesis and transport, which allow the cell to survive in high salinity conditions. There is little need for compatible solutes under low salinity conditions, and biosynthesis and transporter systems need to be repressed. However, the mechanism(s) of this repression is not known. In this study, we showed that CosR played a major role in the regulation of multiple compatible solute systems. Phylogenetic analysis showed that CosR is present in all members of the Vibrionaceae family as well as numerous Gammaproteobacteria. Collectively, these data establish CosR as a global regulator of the osmotic stress response that is widespread in bacteria, controlling many more systems than previously demonstrated.

We characterized 29 bla_CTX-M-27-harboring plasmids of Escherichia coli sequence type 131 (ST131) sublineage C1/H30R isolates from healthy individuals and long-term-care facility (LTCF) residents. Most (27/29) plasmids were of the FIA, FIB, and FII multireplicon type with the same plasmid multilocus sequence typing (pMLST). Several plasmids (7/23) from LTCF residents harbored only bla_CTX-M-27 as the resistance gene; however, their fundamental structures were very similar to those of previously isolated bla_CTX-M-27/F1:A2:B20 plasmids, suggesting their prevalence as a newly arising public health concern.

Most of us will stop renting and become a homeowner one day. But how do you know when it’s a good time to buy your own home? These are four signs that you’re ready to stop renting and become a home owner.

According to American financial expert Dani Pascarella, if any of the three scenarios below apply to you, it’s very likely that home ownership will make your life a lot more stressful than happy.

QR codes, tracking apps and drones at toll booths are just some of the tech tools China is deploying to monitor the spread of the new coronavirus

On bank holiday... Friday. For NHS charities.

Last week, former Vice President Joe Biden told the world that he “unequivocally” denied accusations by Tara Reade, a former staffer in his Senate office, that he sexually assaulted her in the early ’90s.

On Friday evening, Reade responded: Prove it.

“Joe Biden should take the polygraph,” Reade told former television anchor Megyn Kelly, in an interview that aired on Kelly’s YouTube channel. “I will take one if Joe Biden takes one, but I’m not a criminal.”

Read more at The Daily Beast.

Liverpool are looking to make Sadio Mane an offer that would tarnish Real Madrid's hopes of signing him.

New images reveal threads of ultra-hot gas woven throughout the sun's corona, in the most detailed look at previously unseen parts of the atmosphere of our closest star

Megyn Kelly's exclusive sit down with Tara Reade

Your weekly selection of awesome robot videos

Spacecraft propulsion systems are ready for China’s daring touchdown attempt on the red planet

Europe's satellite navigation system enters test phase.

It’s E3 prep week and we missed a show so that means you get a super nice beefy show going into E3. We hope you...

Chris struggles with grains. Anna Marie goes on a month long Final Fantasy journey. Pascal enjoys being called “commander.” Kelley is underwhelmed by her ‘mon....

The actor, best known for playing Gollum in the Lord of the Rings and Hobbit films, will read the entire JRR Tolkien novel

Andy Serkis is to give a continuous, live reading of The Hobbit – lasting around 12 hours – in aid of charity. The actor, best known as Gollum in the Lord of the Rings and Hobbit films, will read the entire book from start to finish with no breaks.

Money raised from the performance will be split equally between NHS Charities Together and Best Beginnings.

Bill Maher said Republicans "don't care" about Tara Reade's sexual assault allegations, saying such claims are simply used as a "unilateral weapon" against Democrats.

Our eyes are open to what Pakistan is doing, Singh said, hours after the NIA arrested a "notorious narco-terrorist" who acted as a conduit for Pakistan-based terror groups.

People with covid-19 appear to be most contagious 15 hours before their symptoms start, and many people may not even go on to develop noticeable symptoms

New York City is the epicentre of the coronavirus outbreak in the US and hospitals are already struggling to treat everyone with covid-19, though the outbreak may not peak for three weeks

The factors that cause flu to decline in spring might apply to covid-19 too. But we don’t know yet if warm weather can curb the spread of the coronavirus

Getting less sleep for five nights in a row can make you view other people’s expressions more negatively, including facial reactions seen over video calls

Dear readers, Speakeasy will no longer be updated as of July 2017. Visit our Arts section for the latest coverage and follow us on Twitter for news and analysis of the entertainment world. Additionally, you can download the WSJ app for iOS or Android to follow your favorite reporters and columnists and receive notifications when they publish new articles.

BEIJING - Grunts, groans and the sound of pulsing music and crashing weights have returned to some of Beijing's gyms after being closed for nearly three months due to the coronavirus outbreak.

More than 3.95 million people have been reported to be infected by the novel coronavirus globally and 273,805 have died, according to a Reuters tally, as of 0214 GMT on Saturday.

The Portuguese midfielder is settling into life in east London well after his loan move.

We test the most powerful, core-laden desktop CPU ever.

The Trump campaign released a new ad in Spanish targeting Democrats for their response to the allegations Tara Reade made against presumptive Democratic nominee Joe Biden.

Tara Reade has claimed in a new interview that Joe Biden used graphic language to proposition her for sex when he allegedly assaulted her in 1993.

Tara Reade addressed her past praise for Joe Biden during an interview released on Friday as well as her cryptic "tic toc" tweet skeptics have pointed to while assessing her claims. 

In her first on-camera interview since the former vice president “unequivocally” denied the sexual assault allegation, Reade says she's willing to be questioned under oath.

MINNEAPOLIS (AP) - As coronavirus hotspots erupted at major U.S. meatpacking plants, experts criticized extremely tight working conditions that made the factories natural high risk contagion locations. But some Midwestern politicians have pointed the finger at the workers' living conditions, suggesting crowded homes bear some blame.

The comments - including ...

You’ve got questions, we’ve got experts

The containment practices of outbreaks past could have lessons for modern epidemics

You've got questions. We've got experts

The fourth installment in our weekly series spotlights titles that may have been lost in the news amid the COVID-19 crisis

The sixth installment in our weekly series spotlights titles that may have been lost in the news amid the COVID-19 crisis

A new study finds that temperature and latitude do not appear to be associated with the spread of coronavirus disease 2019 (COVID-19), but school closures and other public health measures are having a positive effect.

Raise your hand if your inbox is packed. I know mine is. Here are five tips that actually work to get your email in check.

The World Health Organization (WHO) plans to launch an app this month to enable people in under-resourced countries to assess whether they may have the novel coronavirus, and is considering a Bluetooth-based contact tracing feature too, an official told Reuters on Friday.

The French leader said the strict rules "must be respected" over the next four weeks but told the public that the epidemic was "starting to slow down."

Coronavirus: the symptoms Read our LIVE updates on the coronavirus here