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Cytochrome c oxidase (CcO) reduces O2 to water, coupled with a proton-pumping process. The structure of the O2-reduction site of CcO contains two reducing equivalents, Fea32+ and CuB1+, and suggests that a peroxide-bound state (Fea33+–O−–O−–CuB2+) rather than an O2-bound state (Fea32+–O2) is the initial catalytic intermediate. Unexpectedly, however, resonance Raman spectroscopy results have shown that the initial intermediate is Fea32+–O2, whereas Fea33+–O−–O−–CuB2+ is undetectable. Based on X-ray structures of static noncatalytic CcO forms and mutation analyses for bovine CcO, a proton-pumping mechanism has been proposed. It involves a proton-conducting pathway (the H-pathway) comprising a tandem hydrogen-bond network and a water channel located between the N- and P-side surfaces. However, a system for unidirectional proton-transport has not been experimentally identified. Here, an essentially identical X-ray structure for the two catalytic intermediates (P and F) of bovine CcO was determined at 1.8 Å resolution. A 1.70 Å Fe–O distance of the ferryl center could best be described as Fea34+ = O2−, not as Fea34+–OH−. The distance suggests an ∼800-cm−1 Raman stretching band. We found an interstitial water molecule that could trigger a rapid proton-coupled electron transfer from tyrosine-OH to the slowly forming Fea33+–O−–O−–CuB2+ state, preventing its detection, consistent with the unexpected Raman results. The H-pathway structures of both intermediates indicated that during proton-pumping from the hydrogen-bond network to the P-side, a transmembrane helix closes the water channel connecting the N-side with the hydrogen-bond network, facilitating unidirectional proton-pumping during the P-to-F transition.

Optic atrophy 1 (OPA1) is a dynamin protein that mediates mitochondrial fusion at the inner membrane. OPA1 is also necessary for maintaining the cristae and thus essential for supporting cellular energetics. OPA1 exists as membrane-anchored long form (L-OPA1) and short form (S-OPA1) that lacks the transmembrane region and is generated by cleavage of L-OPA1. Mitochondrial dysfunction and cellular stresses activate the inner membrane–associated zinc metallopeptidase OMA1 that cleaves L-OPA1, causing S-OPA1 accumulation. The prevailing notion has been that L-OPA1 is the functional form, whereas S-OPA1 is an inactive cleavage product in mammals, and that stress-induced OPA1 cleavage causes mitochondrial fragmentation and sensitizes cells to death. However, S-OPA1 contains all functional domains of dynamin proteins, suggesting that it has a physiological role. Indeed, we recently demonstrated that S-OPA1 can maintain cristae and energetics through its GTPase activity, despite lacking fusion activity. Here, applying oxidant insult that induces OPA1 cleavage, we show that cells unable to generate S-OPA1 are more sensitive to this stress under obligatory respiratory conditions, leading to necrotic death. These findings indicate that L-OPA1 and S-OPA1 differ in maintaining mitochondrial function. Mechanistically, we found that cells that exclusively express L-OPA1 generate more superoxide and are more sensitive to Ca2+-induced mitochondrial permeability transition, suggesting that S-OPA1, and not L-OPA1, protects against cellular stress. Importantly, silencing of OMA1 expression increased oxidant-induced cell death, indicating that stress-induced OPA1 cleavage supports cell survival. Our findings suggest that S-OPA1 generation by OPA1 cleavage is a survival mechanism in stressed cells.

The arrangement of functionally-related genes in operons is a fundamental element of how genetic information is organized in prokaryotes. This organization ensures coordinated gene expression by co-transcription. Often, however, alternative genetic responses to specific stress conditions demand the discoordination of operon expression. During cold temperature stress, accumulation of the gene encoding the sole Asp–Glu–Ala–Asp (DEAD)-box RNA helicase in Synechocystis sp. PCC 6803, crhR (slr0083), increases 15-fold. Here, we show that crhR is expressed from a dicistronic operon with the methylthiotransferase rimO/miaB (slr0082) gene, followed by rapid processing of the operon transcript into two monocistronic mRNAs. This cleavage event is required for and results in destabilization of the rimO transcript. Results from secondary structure modeling and analysis of RNase E cleavage of the rimO–crhR transcript in vitro suggested that CrhR plays a role in enhancing the rate of the processing in an auto-regulatory manner. Moreover, two putative small RNAs are generated from additional processing, degradation, or both of the rimO transcript. These results suggest a role for the bacterial RNA helicase CrhR in RNase E-dependent mRNA processing in Synechocystis and expand the known range of organisms possessing small RNAs derived from processing of mRNA transcripts.

K. D. Cherednichenko, Yu. Yu. Ershova, A. V. Kiselev and S. N. Naboko
Trans. Moscow Math. Soc. 80 (2020), 251-294.
Abstract, references and article information

I. V. Astashova, D. A. Lashin and A. V. Filinovskii
Trans. Moscow Math. Soc. 80 (2020), 221-234.
Abstract, references and article information

A. A. Vladimirov
Trans. Moscow Math. Soc. 80 (2020), 211-219.
Abstract, references and article information

I. A. Sheipak and T. A. Garmanova
Trans. Moscow Math. Soc. 80 (2020), 189-210.
Abstract, references and article information

N. F. Valeev, Ya. T. Sultanaev and É. A. Nazirova
Trans. Moscow Math. Soc. 80 (2020), 153-167.
Abstract, references and article information

V. A. Sadovnichii, Ya. T. Sultanaev and A. M. Akhtyamov
Trans. Moscow Math. Soc. 80 (2020), 123-131.
Abstract, references and article information

A. G. Sergeev and Kh. A. Khachatryan
Trans. Moscow Math. Soc. 80 (2020), 95-111.
Abstract, references and article information

S. Yu. Orevkov
Trans. Moscow Math. Soc. 80 (2020), 73-81.
Abstract, references and article information

S. A. Nazarov
Trans. Moscow Math. Soc. 80 (2020), 1-51.
Abstract, references and article information

Publication Date: Apr 10 2020 The SEC will withdraw the existing approval order and the fund will become subject to the requirements of Rule 6c-11 and Nasdaq Rule 5704....

Publication Date: May 4 2020 On May 1, 2020, Nasdaq adopted Rule 5636T, operative through, and including, June 30, 2020, to provide listed companies with a temporary exception from certain shareholder approval requirements. A Company must submit an application to Nasdaq’s Listing Qualifications Department demonstrating that the transaction satisfies the requirements in Rule 5636T and must provide the Notification Form: Listing of Additional Shares (“LAS Form”) required by...

1 November 2019

The 'Security and Prosperity in Asia' conference looked at the impact of international law in the Asia-Pacific with a focus on regional economic and security issues such as the South China Sea disputes.

8 January 2020 , Volume 96, Number 1

17 January 2020

Research Event

Event participants

K. Anis Ahmed, Publisher, Dhaka Tribune and Bangla Tribune; Author of Good Night, Mr. Kissinger, Co-director, Dhaka Literary Festival
Meenakshi Ganguly, South Asia Director, Human Rights Watch
Chair: Ed Cumming, Writer, The Independent

Stents are expandable tubes that are inserted into blocked or damaged blood vessels. They offer a practical way to treat coronary artery disease, repairing vessels and keeping them open so that blood can flow freely. When stents work, they are a great alternative to radical surgery, but they can deteriorate or become dislodged. Mathematical models of blood vessels and stents are helping to determine better shapes and materials for the tubes. These models are so accurate that the FDA is considering requiring mathematical modeling in the design of stents before any further testing is done, to reduce the need for expensive experimentation. Precise modeling of the entire human vascular system is far beyond the reach of current computational power, so researchers focus their detailed models on small subsections, which are coupled with simpler models of the rest of the system. The Navier-Stokes equations are used to represent the flow of blood and its interaction with vessel walls. A mathematical proof was the central part of recent research that led to the abandonment of one type of stent and the design of better ones. The goal now is to create better computational fluid-vessel models and stent models to improve the treatment and prediction of coronary artery disease the major cause of heart attacks. For More Information: Design of Optimal Endoprostheses Using Mathematical Modeling, Canic, Krajcer, and Lapin, Endovascular Today, May 2006.

Stents are expandable tubes that are inserted into blocked or damaged blood vessels. They offer a practical way to treat coronary artery disease, repairing vessels and keeping them open so that blood can flow freely. When stents work, they are a great alternative to radical surgery, but they can deteriorate or become dislodged. Mathematical models of blood vessels and stents are helping to determine better shapes and materials for the tubes. These models are so accurate that the FDA is considering requiring mathematical modeling in the design of stents before any further testing is done, to reduce the need for expensive experimentation. Precise modeling of the entire human vascular system is far beyond the reach of current computational power, so researchers focus their detailed models on small subsections, which are coupled with simpler models of the rest of the system. The Navier-Stokes equations are used to represent the flow of blood and its interaction with vessel walls. A mathematical proof was the central part of recent research that led to the abandonment of one type of stent and the design of better ones. The goal now is to create better computational fluid-vessel models and stent models to improve the treatment and prediction of coronary artery disease the major cause of heart attacks. For More Information: Design of Optimal Endoprostheses Using Mathematical Modeling, Canic, Krajcer, and Lapin, Endovascular Today, May 2006.

Researcher: Michael C. Ferris, University of Wisconsin-Madison. Moment Title: Providing Power Description: Michael C. Ferris talks about power grids

Consolidated sales of EUR 146.7 million EBITDA (before IFRS 16) increased strongly by EUR 3.8 million to EUR 2.1 million Forecast for 2019 as a whole confirmed Working capital ratio declines by 2 percentage points to 10.6% euromicron AG, a medium-sized technology group and specialist for the digital networking of business and production processes, published its preliminary figures for the first half of 2019 today.

A new study from University of Michigan climate researchers concludes that some of the latest-generation climate models may be overly sensitive to carbon dioxide increases and therefore project future warming that is unrealistically high.

Researchers at Western and Suncor are teaming up to use algae as a way to produce serological test kits for COVID-19 - a new process that overcomes shortfalls of existing processes while saving money.

In these unprecedented times, we are all spending much more time at home and in our gardens. And, now that spring has well and truly arrived, it's the perfect time to get reacquainted with one of our country's busiest workers - the bee.

Sovereign nations typically measure economic success in terms of GDP (income) but this approach is risky as it fails to track and measure the impact of this on nature. Inclusive wealth, on the other hand captures financial and produced capital, but also the skills in our workforce (human capital), the cohesion in our society (social capital) and the value of our environment (natural capital).

The good thing about BirdLife is that, as a truly global organisation, we're already great at staying connected, even when we're thousands of miles apart. Here are just a few of the ways our work will carry on over the coming months, even if it's from our living rooms.

The surprise player in affecting workplace safety overseas? Multinational buyers.

New Publication: Rules, Procedures and Mechanisms Applicable to Processes under the Cartagena Protocol on Biosafety.

Report of the Fourth Meeting of the Conference of the Parties to the Convention on Biological Diversity Serving as the Meeting of the Parties to the Cartagena Protocol on Biosafety (Advance text)