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Erythromycin-resistance methyltransferases are SAM dependent Rossmann fold methyltransferases that convert A2058 of 23S rRNA to m6 2A2058. This modification sterically blocks binding of several classes of antibiotics to 23S rRNA, resulting in a multidrug-resistant phenotype in bacteria expressing the enzyme. ErmC is an erythromycin resistance methyltransferase found in many Gram-positive pathogens, whereas ErmE is found in the soil bacterium that biosynthesizes erythromycin. Whether ErmC and ErmE, which possess only 24% sequence identity, use similar structural elements for rRNA substrate recognition and positioning is not known. To investigate this question, we used structural data from related proteins to guide site-saturation mutagenesis of key residues and characterized selected variants by antibiotic susceptibility testing, single turnover kinetics, and RNA affinity–binding assays. We demonstrate that residues in α4, α5, and the α5-α6 linker are essential for methyltransferase function, including an aromatic residue on α4 that likely forms stacking interactions with the substrate adenosine and basic residues in α5 and the α5-α6 linker that likely mediate conformational rearrangements in the protein and cognate rRNA upon interaction. The functional studies led us to a new structural model for the ErmC or ErmE-rRNA complex.

Mining and the Circular Economy: Implications for the Minerals and Metals Industries 6 November 2017 — 4:00PM TO 5:30PM Anonymous (not verified) 31 October 2017 Chatham House, London

Environmental Change and Emerging Diseases 28 October 2020 — 3:00PM TO 4:00PM Anonymous (not verified) 13 October 2020 Online

Understanding how environmental changes are directly and indirectly affecting the emergence and spread of disease has assumed global importance.

There is growing awareness that deforestation and land-use conversion, urbanization, human migration, international commerce, and climate change are having significant impacts on human health, but their impact on increasing infectious disease risks has only become more evident with the coronavirus pandemic.

With climate change, and environmental change more generally, disrupting ecologies, and people interacting with wildlife in new ways, it creates the conditions for new diseases to emerge: a better understanding of the health dimensions of environmental change will be critical to managing pandemic risks in future. 

Our event will examine the relationship between environmental change and disease, how these linkages have manifested in historical outbreaks and in the coronavirus pandemic, and the role of environmental policies in minimizing the risk of future emerging diseases.  What can be done to ensure equitable action? What can we learn from our responses to previous pandemics? And will the growing recognition of the diverse risks arising from climate change motivate more climate action?

This event will launch the Energy, Environment and Resources (EER) Programme’s Environment and Society Discussion Series. This series aims to provide a platform to promote interdisciplinary knowledge sharing and policy dialogue to mitigate and adapt to the impacts that climate change, biodiversity loss and natural resource depletion are having on people and communities globally, and on geopolitics, security and international development.

Sign up to find out about more events in this series here. 

What's next for environmental peacebuilding? Lessons learned and opportunities from conflict-affected states 17 February 2021 — 3:00PM TO 4:00PM Anonymous (not verified) 8 February 2021 Online

 This event explores lessons and opportunities from conflict-affected states.

In the field of peacebuilding, scholars and policymakers increasingly recognize the importance of environmental restoration, afforestation and infrastructural renewal for creating the sustainable livelihoods necessary for successful peacebuilding efforts.

Featuring academics writing for International Affairs on environmental peacebuilding in Colombia, Yemen and the Sahel, this webinar discusses the policy implications of the turn to environmental peacebuilding.

This event is part of the Chatham House’s Environment and Society Discussion Series in which the Energy Environment and Resources Programme brings together leading academics and policymakers to discuss key issues in environmental policy.

In particular, this event focuses on the role of environmental peacebuilding in creating sustainable livelihoods. From the impact the destruction of infrastructure can have on poverty as a driver of conflict, to the role environmental peacebuilding can play in bringing communities together by creating sustainable shared spaces of employment, the importance of the environmental livelihood creation is difficult to overstate.

Panellists focus on how policymakers can best encourage inclusive and sustainable livelihood creation and on addressing the key challenges such approaches face in the context of environmental peacebuilding efforts.

Webinar: Hong Kong: Dissent in the Age of Coronavirus 17 April 2020 — 12:00PM TO 1:00PM Anonymous (not verified) 8 April 2020

Street protests demanding greater autonomy and democratization in Hong Kong upended the city for seven months last year. However, with the outbreak of the coronavirus in China in late January, the protests quickly died out. What does this mean for the city’s protest movement?

The speaker will argue that, despite the lack of high-profile street rallies, protest in the city is continuing. It is building on and evolving from last year’s protest movement albeit in different forms. At the same time, the Hong Kong authorities, emboldened by a hard line from Beijing, have begun cracking down on activists and protesters in the city as they seek to put a lid on dissent ahead of important Legislative Council elections scheduled for this September.

In this webinar, the speaker will look at the current state of dissent in Hong Kong and prospects for Hong Kong’s future.

This event will be held on the record.

In many places, fire seasons keep getting longer with larger and ever more destructive wildfires. Teams of mathematicians, computer scientists, meteorologists, and firefighters are working to reduce the number of large fires before they happen and to contain those that do occur. Mark Finney talks about the math involved in modeling and fighting wildfires.

Karen Rios Soto explains how mathematics illuminates the link between air pollution from motor vehicle emissions and asthma. Air pollution causes the premature deaths of an estimated seven million people each year, and it makes life worse for all of us. People with asthma can experience chest tightness, coughing or wheezing, and difficulty breathing when triggered by air pollution. One major source is gas- and diesel-powered cars and trucks, which emit "ultrafine" particles less than 0.1 micrometers across. That's about the width of the virus that causes COVID-19, so tiny that these particles are not currently regulated by the US Environmental Protection Agency. Yet ultrafine particles can easily enter your lungs and be absorbed into your bloodstream, causing health issues such as an asthma attack or even neurodegenerative diseases. Mathematics can help us understand the extent of the problem and how to solve it.

Dr. Valentina Wheeler of University of Wollongong, Australia, shares how her work influences efforts to understand wildfires and red blood cells. In Australia, where bushfires are a concern year-round, researchers have long tried to model these wildfires, hoping to learn information that can help with firefighting policy. Mathematician Valentina Wheeler and colleagues began studying a particularly dangerous phenomenon: When two wildfires meet, they create a new, V-shaped fire whose pointed tip races along to catch up with the two branches of the V, moving faster than either of the fires alone. This is exactly what happens in a mathematical process known as mean curvature flow. Mean curvature flow is a process in which a shape smooths out its boundaries over time. Just as with wildfires, pointed corners and sharp bumps will change the fastest.

Otto Overkamp
Trans. Amer. Math. Soc. 377 (), 5863-5903.
Abstract, references and article information

Kazuhiro Ishige, Paolo Salani and Asuka Takatsu
Trans. Amer. Math. Soc. 377 (), 5705-5748.
Abstract, references and article information

The Moog Image Dump posted a photo:

Bandai Namco 2024

firehouse.ie posted a photo:

firehouse.ie posted a photo:

Anne-Miek Bibbe posted a photo:

JOEPIE: I'm almost there! I wish Uncle Jeroen was here, I'm a little, really just a little bit afraid of the dark.
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JOEPIE: Ik ben bijna bij Peter! Ik wou dat oom Jeroen hier was, ik ben een beetje, echt maar een héél klein beetje bang in het donker.

Lawford Hatcher
Proc. Amer. Math. Soc. 152 (), 5191-5205.
Abstract, references and article information

P. Lochak
St. Petersburg Math. J. 35 (), 477-535.
Abstract, references and article information

Yu. L. Ershov
St. Petersburg Math. J. 35 (), 461-465.
Abstract, references and article information

The Math Community Educational Outreach (Math CEO) program at the University of California, Irvine (UCI) will receive the 2025 AMS Award for an Exemplary Program or Achievement in a Mathematics Department.

Founded in 2014, UCI’s Math CEO is an after-school math enrichment program aimed at increasing the number of talented students in STEM from diverse backgrounds by fostering mathematical exploration, mentor development, and community engagement.

From the citation

The University of California, Irvine (UCI) Math CEO program is recognized for its exceptional contributions to the mathematics community and society at large. Established in 2014 by professors Alessandra Pantano and Li-Sheng Tseng, Math CEO targets students from Title I middle schools, providing them with a high-quality after-school math enrichment program. This program brings middle-school students to the UCI campus to work in small groups with undergraduate mentors, many of whom are also from historically marginalized groups, to engage in challenging mathematical tasks and encourage exploration. 

From September 2019 to June 2024, Math CEO engaged a total of 1,221 youth, with 48.6% identifying as female. The ethnic background of the participants was predominantly Latinx (93.5%), with smaller representations of Asian, white, and multiethnic students. In the same five-year period, Math CEO engaged 553 undergraduate mentors, 62.2% of whom were female. The mentors’ ethnic backgrounds were diverse, with significant representation of Asian (52%) and Latinx (30%) students. The undergraduate mentors, many of whom pursue careers in education, receive training in culturally responsive teaching practices and equity in education, significantly impacting their professional development. In a post-survey, 52.3% of the undergraduate mentors expressed interest in teaching or working in education and 45.9% were likely to pursue professions working with children or families.

Recognizing the central role of families in supporting Latinx youth, Math CEO involves parents through bilingual workshops that enhance community awareness of college pathways and financial opportunities. 

Math CEO has been the foundation for numerous research projects in mathematics education, supported by NSF grants, leading to publications and program growth. The program’s success is evident in its expansion to high schools and other regions in Southern California, including a new branch at California State University, Dominguez Hills. Math CEO continues to make a substantial impact on underserved youth, demonstrating a model of systemic, reproducible change that can be implemented by others.

Response of Alessandra Pantano, UCI Math CEO

I am deeply honored to receive the AMS Award for an Exemplary Program in a Mathematics Department on behalf of the UCI Math CEO team. This wonderful award recognizes the work of many colleagues, graduate students, and undergraduate students in developing and delivering the UCI Math Community Educational Outreach (Math CEO) program. For over a decade, Math CEO has provided creative and culturally responsive math enrichment opportunities for hundreds of underprivileged middle-school students, many of which have since “graduated” to high school or even college. Leading this exceptional and dedicated team of volunteers has been the highest pride of my professional life. A special thanks to my partners-in-crime, Prof. Li-Sheng Tseng, codirector of Math CEO, and former graduate student Andres Forero Cuervo, academic coordinator for Math CEO: We could have never done this without you. I look forward to pushing this activity forward and continuing to dedicate my energy to help kids in our county find the way to express their potential – in math and in life! A big thanks to the colleagues who nominated us and to the AMS for recognizing our efforts.  

History of the program

The UC Irvine Math Community Educational Outreach (Math CEO) program was founded in 2014 by math faculty Alessandra Pantano and Li-Sheng Tseng in collaboration with Santa Ana Unified math teacher Jasmina Matasovic. The founders shared a belief that low standardized test scores in underserved communities do not reflect students’ interest and potential to succeed in STEM. Math CEO runs free, weekly, after-school math enrichment sessions, welcoming all youth regardless of math achievement. Starting with only 25 students from one middle school, the program has grown and engaged nearly two thousand students in all, from multiple school districts in Southern California.

About the award

The annual AMS Award for an Exemplary Program or Achievement in a Mathematics Department was established in 2004 and first given in 2006. This award recognizes a department which has distinguished itself by undertaking an unusual or particularly effective program of value to the mathematics community, internally or in relation to the rest of society. Departments of mathematical sciences in North America that offer at least a bachelor’s degree in mathematical sciences are eligible. The award amount is currently $5,000. The award will be presented at the 2025 Joint Mathematics Meetings in Seattle.

Learn more about the award and previous recipients.

Contact: AMS Communications.

*****

The American Mathematical Society is dedicated to advancing research and connecting the diverse global mathematical community through our publications, meetings and conferences, MathSciNet, professional services, advocacy, and awareness programs.
 

Conroy Overdose's 'Life of a Star' birthday bash sizzled recently at Cool Breeze Entertainment Complex in Church Pen, St Catherine. Glamorous ladies and dapper gents gathered for a night of high fashion and revelry. The Sharper Lane venue pulsed...

An out-of-body experience is the inspiration behind Benzly Hype's latest album Star Its The 7th Year. Released on November 7, the entertainer said the project was done to bring back joy in music and will leave its listeners in an upbeat mood....

Monkeys on the loose Forty-three monkeys escaped from a research facility in South Carolina, USA. The rhesus macaque monkeys fled last Wednesday after a keeper left their pen open at Alpha Genesis -- a company that breeds primates for medical...

As I walked into the embalming room at Jones Funeral Home and Supplies in Kingston on Sunday, I immediately felt the weight of the room. The air was thick with the scent of various chemicals used in the trade permeating the space. Tools such as...

PORT-AU-PRINCE, Haiti (AP) — Haiti's main airport remained closed on Tuesday, a day after violence erupted as the country swore in its new prime minister in a politically tumultuous transition.

Knockout mouse models have been extensively used to study the antiviral activity of IFIT (interferon-induced protein with tetratricopeptide repeats). Human IFIT1 binds to cap0 (m7GpppN) RNA, which lacks methylation on the first and second cap-proximal nucleotides (cap1, m7GpppNm, and cap2, m7GpppNmNm, respectively). These modifications are signatures of “self” in higher eukaryotes, whereas unmodified cap0-RNA is recognized as foreign and, therefore, potentially harmful to the host cell. IFIT1 inhibits translation at the initiation stage by competing with the cap-binding initiation factor complex, eIF4F, restricting infection by certain viruses that possess “nonself” cap0-mRNAs. However, in mice and other rodents, the IFIT1 orthologue has been lost, and the closely related Ifit1b has been duplicated twice, yielding three paralogues: Ifit1, Ifit1b, and Ifit1c. Although murine Ifit1 is similar to human IFIT1 in its cap0-RNA–binding selectivity, the roles of Ifit1b and Ifit1c are unknown. Here, we found that Ifit1b preferentially binds to cap1-RNA, whereas binding is much weaker to cap0- and cap2-RNA. In murine cells, we show that Ifit1b can modulate host translation and restrict WT mouse coronavirus infection. We found that Ifit1c acts as a stimulatory cofactor for both Ifit1 and Ifit1b, promoting their translation inhibition. In this way, Ifit1c acts in an analogous fashion to human IFIT3, which is a cofactor to human IFIT1. This work clarifies similarities and differences between the human and murine IFIT families to facilitate better design and interpretation of mouse models of human infection and sheds light on the evolutionary plasticity of the IFIT family.

Proteins in the α-macroglobulin (αM) superfamily use thiol esters to form covalent conjugation products upon their proteolytic activation. αM protease inhibitors use theirs to conjugate proteases and preferentially react with primary amines (e.g. on lysine side chains), whereas those of αM complement components C3 and C4B have an increased hydroxyl reactivity that is conveyed by a conserved histidine residue and allows conjugation to cell surface glycans. Human α2-macroglobulin–like protein 1 (A2ML1) is a monomeric protease inhibitor but has the hydroxyl reactivity–conveying histidine residue. Here, we have investigated the role of hydroxyl reactivity in a protease inhibitor by comparing recombinant WT A2ML1 and the A2ML1 H1084N mutant in which this histidine is removed. Both of A2ML1s' thiol esters were reactive toward the amine substrate glycine, but only WT A2ML1 reacted with the hydroxyl substrate glycerol, demonstrating that His-1084 increases the hydroxyl reactivity of A2ML1's thiol ester. Although both A2ML1s conjugated and inhibited thermolysin, His-1084 was required for the conjugation and inhibition of acetylated thermolysin, which lacks primary amines. Using MS, we identified an ester bond formed between a thermolysin serine residue and the A2ML1 thiol ester. These results demonstrate that a histidine-enhanced hydroxyl reactivity can contribute to protease inhibition by an αM protein. His-1084 did not improve A2ML1's protease inhibition at pH 5, indicating that A2ML1's hydroxyl reactivity is not an adaption to its acidic epidermal environment.

CD81 plays a central role in a variety of physiological and pathological processes. Recent structural analysis of CD81 indicates that it contains an intramembrane cholesterol-binding pocket and that interaction with cholesterol may regulate a conformational switch in the large extracellular domain of CD81. Therefore, CD81 possesses a potential cholesterol-sensing mechanism; however, its relevance for protein function is thus far unknown. In this study we investigate CD81 cholesterol sensing in the context of its activity as a receptor for hepatitis C virus (HCV). Structure-led mutagenesis of the cholesterol-binding pocket reduced CD81–cholesterol association but had disparate effects on HCV entry, both reducing and enhancing CD81 receptor activity. We reasoned that this could be explained by alterations in the consequences of cholesterol binding. To investigate this further we performed molecular dynamic simulations of CD81 with and without cholesterol; this identified a potential allosteric mechanism by which cholesterol binding regulates the conformation of CD81. To test this, we designed further mutations to force CD81 into either the open (cholesterol-unbound) or closed (cholesterol-bound) conformation. The open mutant of CD81 exhibited reduced HCV receptor activity, whereas the closed mutant enhanced activity. These data are consistent with cholesterol sensing switching CD81 between a receptor active and inactive state. CD81 interactome analysis also suggests that conformational switching may modulate the assembly of CD81–partner protein networks. This work furthers our understanding of the molecular mechanism of CD81 cholesterol sensing, how this relates to HCV entry, and CD81's function as a molecular scaffold; these insights are relevant to CD81's varied roles in both health and disease.

Iron is an essential micronutrient, and, in the case of bacteria, its availability is commonly a growth-limiting factor. However, correct functioning of cells requires that the labile pool of chelatable “free” iron be tightly regulated. Correct metalation of proteins requiring iron as a cofactor demands that such a readily accessible source of iron exist, but overaccumulation results in an oxidative burden that, if unchecked, would lead to cell death. The toxicity of iron stems from its potential to catalyze formation of reactive oxygen species that, in addition to causing damage to biological molecules, can also lead to the formation of reactive nitrogen species. To avoid iron-mediated oxidative stress, bacteria utilize iron-dependent global regulators to sense the iron status of the cell and regulate the expression of proteins involved in the acquisition, storage, and efflux of iron accordingly. Here, we survey the current understanding of the structure and mechanism of the important members of each of these classes of protein. Diversity in the details of iron homeostasis mechanisms reflect the differing nutritional stresses resulting from the wide variety of ecological niches that bacteria inhabit. However, in this review, we seek to highlight the similarities of iron homeostasis between different bacteria, while acknowledging important variations. In this way, we hope to illustrate how bacteria have evolved common approaches to overcome the dual problems of the insolubility and potential toxicity of iron.

Sirtuin 6, SIRT6, is critical for both glucose and lipid homeostasis and is involved in maintaining genomic stability under conditions of oxidative DNA damage such as those observed in age-related diseases. There is an intense search for modulators of SIRT6 activity, however, not many specific activators have been reported. Long acyl-chain fatty acids have been shown to increase the weak in vitro deacetylase activity of SIRT6 but this effect is modest at best. Herein we report that electrophilic nitro-fatty acids (nitro-oleic acid and nitro-conjugated linoleic acid) potently activate SIRT6. Binding of the nitro-fatty acid to the hydrophobic crevice of the SIRT6 active site exerted a moderate activation (2-fold at 20 μm), similar to that previously reported for non-nitrated fatty acids. However, covalent Michael adduct formation with Cys-18, a residue present at the N terminus of SIRT6 but absent from other isoforms, induced a conformational change that resulted in a much stronger activation (40-fold at 20 μm). Molecular modeling of the resulting Michael adduct suggested stabilization of the co-substrate and acyl-binding loops as a possible additional mechanism of SIRT6 activation by the nitro-fatty acid. Importantly, treatment of cells with nitro-oleic acid promoted H3K9 deacetylation, whereas oleic acid had no effect. Altogether, our results show that nitrated fatty acids can be considered a valuable tool for specific SIRT6 activation, and that SIRT6 should be considered as a molecular target for in vivo actions of these anti-inflammatory nitro-lipids.

Programmed ribosomal frameshifting (PRF) is a mechanism used by arteriviruses like porcine reproductive and respiratory syndrome virus (PRRSV) to generate multiple proteins from overlapping reading frames within its RNA genome. PRRSV employs −1 PRF directed by RNA secondary and tertiary structures within its viral genome (canonical PRF), as well as a noncanonical −1 and −2 PRF that are stimulated by the interactions of PRRSV nonstructural protein 1β (nsp1β) and host protein poly(C)-binding protein (PCBP) 1 or 2 with the viral genome. Together, nsp1β and one of the PCBPs act as transactivators that bind a C-rich motif near the shift site to stimulate −1 and −2 PRF, thereby enabling the ribosome to generate two frameshift products that are implicated in viral immune evasion. How nsp1β and PCBP associate with the viral RNA genome remains unclear. Here, we describe the purification of the nsp1β:PCBP2:viral RNA complex on a scale sufficient for structural analysis using small-angle X-ray scattering and stochiometric analysis by analytical ultracentrifugation. The proteins associate with the RNA C-rich motif as a 1:1:1 complex. The monomeric form of nsp1β within the complex differs from previously reported homodimer identified by X-ray crystallography. Functional analysis of the complex via mutational analysis combined with RNA-binding assays and cell-based frameshifting reporter assays reveal a number of key residues within nsp1β and PCBP2 that are involved in complex formation and function. Our results suggest that nsp1β and PCBP2 both interact directly with viral RNA during formation of the complex to coordinate this unusual PRF mechanism.

28 July 2020

20 August 2020