With 22 senior citizens from Madurai, who were on a pilgrimage to north India, stranded in Gaya in Bihar for over 40 days following the lockdown, fami

The bacterial type VI secretion system (T6SS) secretes many toxic effectors to gain advantage in interbacterial competition and for eukaryotic host infection. The cognate immunity proteins of these effectors protect bacteria from their own effectors. PldB is a T6SS trans-kingdom effector in Pseudomonas aeruginosa that can infect both prokaryotic and eukaryotic cells. Three proteins, PA5086, PA5087 and PA5088, are employed to suppress the toxicity of PldB-family proteins. The structures of PA5087 and PA5088 have previously been reported, but the identification of further distinctions between these immunity proteins is needed. Here, the crystal structure of PA5086 is reported at 1.90 Å resolution. A structural comparison of the three PldB immunity proteins showed vast divergences in their electrostatic potential surfaces. This interesting phenomenon provides an explanation of the stockpiling mechanism of T6SS immunity proteins.

The non-porous three-dimensional structure of poly[(μ5-2-amino­benzene-1,4-di­carboxyl­ato)(μ6-oxalato)(oxomium)europium(III)], [Eu(C8H5NO4)(C2O4)(H3O)]n or [EuIII(NH2–BDC)(ox)(H3O)]n (NH2–BDC2− = 2-amino­terephthalate and ox2− = oxalate) is constructed from two-dimensional layers of EuIII–carboxyl­ate–oxalate, which are connected by NH2–BDC2− pillars. The basic structural unit of the layer is an edge-sharing dimer of TPRS-{EuIIIO9}, which is assembled through the ox2− moiety. The intra­layer void is partially occupied by TPR-{EuIIIO6} motifs. Weak C—H⋯O and strong, classical intra­molecular N—H⋯O and inter­molecular O—H⋯O hydrogen-bonding inter­actions, as well as weak π–π stacking inter­actions, affix the organic pillars within the framework. The two-dimensional layer can be simplified to a uninodal 4-connected sql/Shubnikov tetra­gonal plane net with point symbol {44.62}.

Hybrid photon-counting detectors are widely established at third-generation synchrotron facilities and the specifications of the Pilatus3 X CdTe were quickly recognized as highly promising in charge-density investigations. This is mainly attributable to the detection efficiency in the high-energy X-ray regime, in combination with a dynamic range and noise level that should overcome the perpetual problem of detecting strong and weak data simultaneously. These benefits, however, come at the expense of a persistent problem for high diffracted beam flux, which is particularly problematic in single-crystal diffraction of materials with strong scattering power and sharp diffraction peaks. Here, an in-depth examination of data collected on an inorganic material, FeSb2, and an organic semiconductor, rubrene, revealed systematic differences in strong intensities for different incoming beam fluxes, and the implemented detector intensity corrections were found to be inadequate. Only significant beam attenuation for the collection of strong reflections was able to circumvent this systematic error. All data were collected on a bending-magnet beamline at a third-generation synchrotron radiation facility, so undulator and wiggler beamlines and fourth-generation synchrotrons will be even more prone to this error. On the other hand, the low background now allows for an accurate measurement of very weak intensities, and it is shown that it is possible to extract structure factors of exceptional quality using standard crystallographic software for data processing (SAINT-Plus, SADABS and SORTAV), although special attention has to be paid to the estimation of the background. This study resulted in electron-density models of substantially higher accuracy and precision compared with a previous investigation, thus for the first time fulfilling the promise of photon-counting detectors for very accurate structure factor measurements.

Enterotoxigenic Escherichia coli (ETEC) are common agents of diarrhea for travelers and a major cause of mortality in children in developing countries. To attach to intestinal cells ETEC express colonization factors, among them CFA/I, which are the most prevalent factors and are the archetypical representative of class 5 pili. The helical quaternary structure of CFA/I can be unwound under tensile force and it has been shown that this mechanical property helps bacteria to withstand shear forces from fluid motion. We report in this work the CFA/I pilus structure at 4.3 Å resolution from electron cryomicroscopy (cryo-EM) data, and report details of the donor strand complementation. The CfaB pilins modeled into the cryo-EM map allow us to identify the buried surface area between subunits, and these regions are correlated to quaternary structural stability in class 5 and chaperone–usher pili. In addition, from the model built using the EM structure we also predicted that residue 13 (proline) of the N-terminal β-strand could have a major impact on the filament's structural stability. Therefore, we used optical tweezers to measure and compare the stability of the quaternary structure of wild type CFA/I and a point-mutated CFA/I with a propensity for unwinding. We found that pili with this mutated CFA/I require a lower force to unwind, supporting our hypothesis that Pro13 is important for structural stability. The high-resolution CFA/I pilus structure presented in this work and the analysis of structural stability will be useful for the development of novel antimicrobial drugs that target adhesion pili needed for initial attachment and sustained adhesion of ETEC.

Many biologists are now routinely seeking to determine the three-dimensional structures of their proteins of choice, illustrating the importance of this knowledge, but also of the simplification and streamlining of structure-determination processes. Despite the fact that most software packages offer simple pipelines, for the non-expert navigating the outputs and understanding the key aspects can be daunting. Here, the structure determination of the type IV pili (TFP) protein PilA1 from Clostridioides difficile is used to illustrate the different steps involved, the key decision criteria and important considerations when using the most common pipelines and software. Molecular-replacement pipelines within CCP4i2 are presented to illustrate the more commonly used processes. Previous knowledge of the biology and structure of TFP pilins, particularly the presence of a long, N-terminal α-helix required for pilus formation, allowed informed decisions to be made during the structure-determination strategy. The PilA1 structure was finally successfully determined using ARCIMBOLDO and the ab initio MR strategy used is described.

Detailed analysis of the high-flux deficiencies of pixel-array detectors leads to a protocol for the measurement of structure factors of unprecedented accuracy even for inorganic materials, and this significantly advances the prospects for experimental electron-density investigations.

The structure of the Pseudomonas aeruginosa T6SS PldB immunity protein PA5086 is reported at 1.9 Å resolution. Comparison of PA5086 with its homologs PA5087 and PA5088 showed great similarities in sequence and structure, but vast divergences in electrostatic potential surfaces.

Testing caterpillars’ taste buds is no simple task. Just like your local salad bar, plants in the wild come in different shapes, textures and flavors. Herbivores rely on each of these cues to tell them what to eat. Deciphering this code is Lind’s task. He’s examining 40 different plant species – half invasive, half native.

The post Salad science: Coaxing caterpillars to reveal the secrets of their leafy desires appeared first on Smithsonian Insider.

Thunder, lightning and strong winds greeted the National Zoo’s two female red panda cubs when they were born June 17, and that stormy night has […]

The post National Zoo’s red pandas named “Pili” and “Damini” for stormy night appeared first on Smithsonian Insider.

Scientists at the Smithsonian Tropical Research Institute (STRI) in Panama compared the diets of two caterpillar species, expecting the one that exclusively consumed plants containing […]

The post Colorful Caterpillar Chemists appeared first on Smithsonian Insider.

“Our guide celebrates the beauty of some of the most attractive inhabitants of Panama’s undersea realm and provides an indispensable, easy-to-use tool for their identification,” say the Littlers.

The post Researchers compile colorful on-line guide to marine algae of Panama appeared first on Smithsonian Insider.

By now, most of the United States has started to feel the first cool caresses of winter. Everything is pumpkin spiced, and the last crickets […]

The post Feathered diplomats unite pupils in North and Central America appeared first on Smithsonian Insider.

The numerous technical and operational breakdowns that contributed to the Deepwater Horizon oil rig explosion and spill from the Macondo well in the Gulf of Mexico suggest the lack of a suitable approach for managing the inherent risks.

The Gulf Research Program (GRP) of the National Academies of Sciences, Engineering, and Medicine today announced grant awards for seven new projects totaling $5.3 million.

The Gulf Research Program (GRP) of the National Academies of Sciences, Engineering, and Medicine is collaborating with the Sea Grant Oil Spill Science Outreach Program to convene a series of workshops aimed at improving community preparedness for future oil spills.

A new report from the National Academies of Sciences, Engineering, and Medicine examines the effects and efficacy of using dispersants in marine oil spill response.

New research has shed light on the factors needed to successfully implement pilot projects designed to reduce the dumping of unwanted fish by fishermen. The analysis of 15 European projects highlights the importance of involving the fishing industry in developing and implementing pilot projects.

Birth control pills in 1976 in New York. The birth control pill was approved by the FDA 60 years ago this week.; Credit: /Bettmann/Getty Images

Updated at 9:44 a.m. ET

As a young woman growing up in a poor farming community in Virginia in the 1940 and '50s, with little information about sex or contraception, sexuality was a frightening thing for Carole Cato and her female friends.

"We lived in constant fear, I mean all of us," she said. "It was like a tightrope. always wondering, is this going to be the time [I get pregnant]?"

Cato, 78, now lives in Columbia, S.C. She grew up in the years before the birth control pill was approved by the U.S. Food and Drug Administration, on May 9, 1960. She said teenage girls in her community were told very little about how their bodies worked.

"I was very fortunate; I did not get pregnant, but a lot of my friends did. And of course, they just got married and went into their little farmhouses," she said. "But I just felt I just had to get out."

At 23, Cato married a widower who already had seven children. They decided seven was enough.

By that time, Cato said, the pill allowed the couple to avoid having more babies — and she eventually was able to go on to college.

"It was just like going from night to day, as far as the freedom of it," Cato said. "And to know that I had control, that I had choice, that I controlled my body. It gave me a whole new lease on life."

Loretta Ross, an activist and visiting women's studies professor at Smith College, was among the first generation of young women to have access to the birth control pill throughout their reproductive years.

Ross, now 66, said by the time she came of age around 1970, the pill was giving young women more control over their fertility than previous generations had enjoyed.

"We could talk about having sex – not without consequences, because there were still STDS ... but at the same time, with more freedom than our foremothers had," Ross said. "So it changed the world."

For all it's done for women, Ross said that the pill has a complex and controversial history; it was first tested on low-income women in Puerto Rico. Ross said the pill also has limitations; she'd like to see it made available over the counter, as it is in some countries – not to mention, a pill for men.

When the pill was approved in 1960, women had few relatively few contraceptive options, and the pill offered more reliability and convenience than methods like condoms or diaphragms, said Dr. Eve Espey, chair of the Department of Ob/Gyn and Family Planning at the University of New Mexico.

"There was a huge, pent-up desire for a truly effective form of contraception, which had been lacking up to that point," Espey said.

By 1965, she said, 40% of young married women were on the pill.

For Pat Fishback, now 80 and living in Richmond, Va., the newly-available pill allowed her to delay having children in her early 20s until she'd been married for a couple of years.

"It also made having children a positive experience," Fishback said. "Because we had actually, emotionally and intellectually, gotten to the point where we really desired to have children."

It took a bit longer for unmarried women to gain widespread access to the pill and other forms of contraception: Linda Gordon, 80, a historian at New York University, remembers the stigma around single women and contraception at the time.

"When I was in college, a number of women had a wedding ring – a gold ring –that we would pass around and use when we wanted to go see a doctor to get fitted for a diaphragm," Gordon said. "In other words, there were people finding their way to do that, even then."

The pill also gave rise to a variety of other forms of hormonal contraception, many of which are popular today, Gordon said. According to the Centers for Disease Control and Prevention, nearly 13% of American women of reproductive age use the pill — making it the second most popular form of contraception, after female sterilization.

Gordon said that 60 years after the pill's approval, contraception remains a contentious political issue.

Just this week, the U.S. Supreme Court heard arguments in a case involving the birth control mandate in the Affordable Care Act. A decision on whether some institutions with religious or moral objections can deny contraceptive coverage to their employees is expected in the months to come.

This content is from Southern California Public Radio. View the original story at SCPR.org.

The risk of small or medium oil spills from ships, pipelines, storage facilities and refineries is higher than from oil exploration and production. However, the risk of severe oil spills is highest from exploration and production, according to a recent study. Furthermore, the study suggests that the Deepwater Horizon accident, the largest recorded oil spill, cannot be considered as a particularly rare event.

Sediments collected from coastal Louisiana over a year after the Deepwater Horizon oil spill in the Gulf of Mexico have been found to cause health defects in the Gulf killifish. Nearly all adult fish studied had signs of significantly altered gene function and embryos exposed to polluted sediment were less likely to hatch

A new oil-spill risk-management system has been developed by researchers, which shows the likely effects of a coastal spill on the environment and economic activities for specific locations. It provides maps of oil-spill risk through a web portal and could help decision makers and emergency-response authorities protect the local environment and businesses through targeted and efficient planning and responses.

Congestion schemes can encourage people to adopt environmentally friendly behaviours more generally, a new study suggests. Researchers who surveyed car owners after the introduction of a congestion scheme in Stockholm found that after its introduction nearly half of people surveyed adopted greener behaviours such as conserving energy and water.

A pilot Marine Spatial Planning (MSP) project in the UK has found MSP to be a useful approach in managing marine waters sustainably. Sharing the knowledge and experiences gained in developing the Shetland Islands’ Marine Spatial Plan (SMSP) can help other authorities in the process of developing similar plans, says the project team.

There are more than 30,000 microwave ovens, AC and washing machines which needs repair at a time when Indians are locked indoors and doing household chores themselves due to the lockdown.

In 1989 a large oil tanker famously ran aground off the Alaskan coast, spilling 11 million gallons of crude oil into the waters of the Prince William Sound. Over 20 years later oil still contaminates some of the nearby gravel beaches. A recent study suggests it is the physical condition of the beaches that has caused the oil to persist. This research could provide guidelines for remediating susceptible beaches worldwide.

The recent oil spill in the Gulf of Mexico has highlighted the need to effectively evaluate possible response strategies. A new decision support tool can be used to consider the environmental, socio-economic and management effects of different responses to spills, translating them into monetary terms to provide a common currency for comparison.

New research compared criteria for accepting environmental risk as tools to evaluate cost-effective measures that would prevent tanker oil spills. The results suggest that the Cost of Averting one Tonne of Spilled oil (CATS) criterion is the best candidate, as it appears to be both practical and meaningful in actual risk assessments, and can lead to sensible recommendations.

The Deepwater Horizon Oil Spill saw the first ever use of chemical dispersants to reduce the impacts of an oil spill at a deepwater level. A new study has investigated the fate of these dispersants in deepwater and concluded that they do not biodegrade well.

Marine microorganisms responded to the Deepwater Horizon oil spill by boosting the abundance of species capable of breaking down crude oil, according to new research. This method of ‘bioremediation’ could help manage crises in deep sea environments, where other clean-up methods are ineffective.

A new study of clean-up workers seven years after the 2002 Prestige oil tanker spillage has found potential evidence for long-term impacts on their hormonal and immune systems as a result of exposure to the oil. The results suggest new health surveillance measures may be appropriate for workers involved in future oil clean-up operations.

Oil spills can affect seabird populations for at least a decade after a major incident, a new study suggests. The authors studied the long-term effects of the Prestige oil spill on European shags and found that the numbers of chicks raised by breeding pairs were reduced in the ten years following the disaster.

Oil spills can decimate seabird populations. Some birds can be saved, if the oil is washed from their feathers in time; however, this long process is stressful for the birds and requires numerous volunteers. Researchers have now developed a ‘bird-washing machine’ which reduces the washing time from two hours to four minutes. When trialled on oiled birds rescued from the Caspian Sea this resulted in a substantial increase in survival: 88.5% survival after seven days compared to 50% survival with current washing techniques.

Oil spills at sea can be catastrophic events, with oil and discharged toxins, including polycyclic aromatic hydrocarbons, threatening marine wildlife and coastlines, damaging healthy ecosystems and harming livelihoods. A recent study found that using dispersants moderately decreased the number of cod eggs and larvae affected by spills off the Norwegian coast.

Migrating tundra peregrine falcons (Falco peregrinus tundrius) experienced increased levels of harmful hydrocarbons in their blood following the 2010 Deepwater Horizon oil spill in the Gulf of Mexico, a new study finds. Blood from juvenile females was found to have the highest levels of contamination.

European Atlantic countries are, in general, at higher risk of being affected by oil spills than Mediterranean and Baltic countries, with the United Kingdom most affected, according to new research. The study developed a new risk index for analysing the potential vulnerability of coastal regions to oil spills at sea.

A recent analysis of indoor industrial air pollutants could be useful for implementing REACH (Registration, Evaluation and Authorisation of Chemicals). Implementation of REACH should be based on sound analytical methods and targeting of priority chemicals, according to the researchers.