Share Associated PressConservative MP Tobias Ellwood, left, stands amongst the emergency services at the scene outside the Palace of Westminster, London, Wednesday, March 22, 2017. London police say they are treating a gun and knife incident at Britain’s Parliament “as a terrorist incident until we know otherwise.” The Metropolitan Police says in a statement that the incident is ongoing. It is urging people to stay away from the area. Officials say a man with a knife attacked a police officer at Parliament and was shot by officers. Nearby, witnesses say a vehicle struck several people on the Westminster Bridge. (Stefan Rousseau/PA via AP).The Islamic State group claimed responsibility Thursday for an attack by a man who plowed an SUV into pedestrians on one of London’s famous bridges and then stabbed a police officer to death at Britain’s Parliament. In a somber but defiant statement, Britain’s prime minister declared that “we are not afraid.” The man who killed three people Wednesday and was shot to death by police was born in Britain and once came under investigation for links to religious extremism, British Prime Minister Theresa May said Thursday in a sweeping speech before the House of Commons. British officials named the attacker as Khalid Masood, a 52-year-old with criminal convictions who was living in the West Midlands, which includes the central city of Birmingham. Police raided properties in London and Birmingham, and made eight arrests. An Utah man visiting London with his wife for their 25th anniversary and a British woman who was a school administrator were killed by the SUV attack on Westminster Bridge and at least 29 others were hospitalized, seven critically. May set an unyielding tone Thursday, saluting the heroism of police as well as the ordinary actions of everyone who went about their lives in the aftermath. “As I speak millions will be boarding trains and airplanes to travel to London, and to see for themselves the greatest city on Earth,” she told the House of Commons. “It is in these actions – millions of acts of normality – that we find the best response to terrorism —a response that denies our enemies their victory, that refuses to let them win, that shows we will never give in.” Parliament began its moment of silence at 9:33 a.m., honoring the shoulder number of the slain officer, Keith Palmer, a 15-year veteran of the Metropolitan Police and a former soldier. Then Parliament, which was locked down after the attack, returned to business — a counter to those who had attacked British democracy. In 1,000-year-old Westminster Hall, the oldest part of Parliament’s buildings, politicians, journalists and parliamentary staff lined up to sign a book of condolences for the victims. Among them was a uniformed policeman, who wrote: “Keith, my friend, will miss you.” The rampage was the first deadly incident at Parliament since 1979, when Conservative lawmaker Airey Neave was killed in a car bombing by Irish militants. Some parliamentarians said they were shaken, and all were somber. But they were also determined. “There is no such thing as 100 percent security,” said Menzies Campbell, a member of the House of Lords. “We have to learn to live with that.” The London attack echoed deadly vehicle rampages in Nice, France, and Berlin last year that IS has claimed. The Islamic State group said through its Aamaq News Agency that the London attacker was a soldier of the Islamic State who “carried out the operation in response to calls for targeting citizens of the coalition” of countries fighting IS in Syria and Iraq. The IS group has been responsible for numerous bloody attacks around the globe and has specifically called for Western followers to carry out this kind of attack in their own countries, though the group has also claimed events later found to have no clear links to it. Police believe the attacker acted alone and there is no reason to believe “imminent further attacks” are planned, May said. He had been investigated before but police believed he was a peripheral figure, May said. Labour Party lawmaker Khalid Mahmood, who represents part of Birmingham, condemned the “barbaric attack” and urged his fellow Muslims to report concerns about radicalization to the police. “We have to condemn this outright,” he said. “There are no ifs or buts. This is a hugely tragic incident. These people do not belong to any faith. They certainly don’t belong to my faith of Islam.” Mahmood said the attacker and those like him “should be condemned by everybody and this shouldn’t serve as a tool for division within our community.” Many suspects in British terror attacks and plots have roots in the city, which has been described in a recent terror analysis by the Henry Jackson Society conservative think tank as a center for Islamist extremism. Several local mosques have also been linked to extremist clerics. British security forces have foiled 13 plots in the past four years. There are currently thousands of extremists in the U.K. who are known to officials but only a fraction of whom are under surveillance, according to a security official who spoke on condition of anonymity because he was not authorized to speak about ongoing security operations. It takes dozens of officers to watch just one terror suspect. Witnesses said the attacker went straight after the police officer after ramming into the pedestrians. “This man got out of the car with two knives in his hands and while he was running he was stabbing people. He arrived in front of the entrance to the parliament and he started to stab a policeman,” said Vincenzo Mangiacarpe, an Italian boxer who was visiting Parliament. “You can imagine if someone was playing a drum on your back with 2 knives – he gave him around 10 stabs in the back, then he left the policeman and he came toward us.” Metropolitan Police counterterrorism chief Mark Rowley revised the death toll from five to four, including the attacker. He said 29 people required hospitalization and seven of them were in critical condition. He also said that authorities were still working out the number of “walking wounded.” Police had previously given the total number of wounded in Wednesday’s attack as around 40. May said people from 11 countries were among the victims. They included 12 Britons, three French, two Romanians, four South Koreans, one German, one Pole, two Irish, one Chinese, one Italian, one American and two Greeks required hospital treatment. Kurt Cochran, a Utah man visiting London with his wife Melissa for their 25th anniversary, was named as among the dead by the Church of Jesus Christ of Latter-day Saints. She was seriously injured in the attack as is still hospitalized. President Donald Trump was among the world leaders offering their condolences. London has been a target for terrorism many times over past decades and the threat level for the British capital was already listed at severe, meaning an attack was “highly likely.” Just this weekend, hundreds of armed police took part in an exercise simulating a “marauding” terror attack on a tourist boat on the River Thames. May said the attack in London targeted “free people everywhere,” and she said she had a response for those behind it: “You will not defeat us.”
We can state this distinction more directly. eukaryotes run one very specialized version of the electron transport chain while procaryotes run a more generalized system of multiple simultaneously operating electron transport chains. In eukaryotes, it looks something like this:NADH → Complex I → Q → Complex III → cytochrome c → Complex IV → O2 NADH (dehydrogenase) is the electron donor, Complexes I, III and IV are proton pumps, Q is the membrane soluble mobile electron carriers—the quinone pool, and cytochrome c the soluble electron carrierThe prokaryotic chain (bacteria and archaea), on the other hand, includes multiple donors that can input electrons at three levels. Not only are there typically several different initial dehydrogenases used here, there are often different membrane soluble electron carriers that can contribute to the quinone pool, and multiple oxidases and reductases. Borrowing directly from Wikipedia, the generalized schematic looks like this: All schoolchildren learn that the difference between eukaryotes and prokaryotes has something to do with a nucleus. This is usually around the same time they learn that the mitochondria is the powerhouse of the cell. The real difference between these two life forms, however, has more to do with how they control the flow of electrons to make their living, i.e., their electron transport chains going from donors to acceptors via redox reactions. © 2018 Phys.org Although eukaryotes use just one instance of this chain, they have been able to borrow a few tricks from prokaryotes that they can call upon when needed. Under certain circumstances, reverse electron flow can occur at one or more of the respiratory complexes. One thing we left out in the eukaryotic chain above is complex II, which is a branch point that feeds into the Q pool. In a post here on Wednesday, we discussed in some detail how this particular enzyme system (Succinate dehydrogenase) is regulated in the brain by GABA to regulate mitochondrial access to purine nucleotides. Succinate dehydrogenase is also a major stop on the citric acid cycle. When there are local reversals in the direction of the citric acid cycle here, there must also be reverse electron transport at complex II in respiration.Quinones I have known and lovedA recent paper published in eLife describes how and when this occurs in a peculiar protist called pygsuia. The authors discovered that this organism makes a special kind of quinone using an enzyme that it acquired from bacteria by horizontal gene transfer. Pysugia is an anaerobe and it no longer retains full blown mitochondria. Instead, it uses remnant organelles similar to hydrogenosomes. Instead of using coenzyme Q10 (ubiquinone), like humans use in their quinone pool, Pysugia modifies ubiquinone to a molecule called rhodoquinone (RQ) using a specific methyltransferase to replace one methoxy group with an amine. Credit: eLife (2018). DOI: 10.7554/eLife.34292 Credit: Matthew W. Brown et al / Proc. R. Soc. B. doi: 10.1098/rspb.2013.1755 This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore further Citation: Wisdom of the protists; electron flow tricks for controlling cancer (2018, May 18) retrieved 18 August 2019 from https://phys.org/news/2018-05-wisdom-protists-electron-cancer.html Journal information: eLife The beauty of RQ is that it retains all the structural assets that make ubiquinone so useful—essentials like multiple oxidation states and adjustable length lipid soluble isoprenoid tails for membranes of different thicknesses—but has a reduction potential significantly more negative than ubiquinone (-63 mv vs +100mv). What this means for electron transport is that the reverse reaction at complex II, namely the reduction of fumarate to succinate, becomes much more favorable. When there is no oxygen around (which is normally the terminal electron acceptor used at complex IV), there is little reason for organisms like pysugia to retain any respiratory complexes beyond succinate dehydrogenase. Therefore, they reoxidize RQH2 back to its original RQ form at complex II and generate succinate. Complex I can then cycle again. RQ is not the only alternative to ubiquinone. Bacteria frequently make use of the menaquinone (aka vitamin K2), which is the molecule we utilize for carboxylation of glutamate residues in our coagulation pathway proteins. Plants use phylloquinone (vitamin K1) in photosystem I, and plastoquinone in photosystem II, which has methyl groups in place of ubiquinol’s methoxy groups. Some makers of dubious anti-aging miracle molecules have been known to peddle various plastoquinone-related derivatives. One potential supplement called SkQ1 was specifically designed to penetrate mitochondrial membranes. Another, SkQR1 is a rhodamine-containing analog that has antioxidant and protonophore activity.Many mammalian parasites have a life cycle that requires transit through tissues with widely different oxygen levels in order for them to mature. Some of them, like the ascaris nematode, have managed to get the best of both worlds. They can print off different versions of complex II subunit, along with different Q pool electron carriers, and optimally run reverse electron transport as oxygen levels require. Adult ascaris worms live in low-oxygen intestines and expel their eggs with the feces of their host. When a larva is ingested by a new host, it hatches and invades its intestinal wall, then proceeds to migrate through the host’s organs until it eventually winds up in the lungs, where oxygen alters development. By some hideous magic only a parasite could appreciate, ascaris causes the host to violently cough up the maturing larva, after which they are subsequently swallowed and directed again to the small intestine. Here, they turn off production of complex III and IV, but can continue to make ATP by pumping protons and oxidizing NADH at complex I while recycling RQ at complex II. When organisms like ascaris, or E. coli, or C. elegans maintain dedicated enzymes for running reverse electron transport at complex II, these enzymes are called fumarate reductases as opposed to succinate dehydrogenases.If you need to kill any such parasite lurking within you, this can be a special thing. Researchers have uncovered compounds, like nafuredin, that specifically inhibit the NADH dehydrogenase complex in the mitochondria of helminths. Similarly, atpenin and flutolanil inhibit complex II at its quinone binding site. To appreciate why we said ‘controlling cancer’ in the headline, we need to open one final gift from science: Many human cancers can thrive in poorly vascularized centers of tumors or other low-oxygen pockets in the body. Of particular note, fumarate respiration has been observed in many kinds of cancer.Ascaris makes different varieties of each of Complex II’s four subunits; a flavoprotein subunit (Fp), iron–sulfur subunit (Ip), cytochrome b large subunit (CybL), and cytochrome b small subunit (CybS). Humans don’t have special RQ quinones, nor do they keep any bonafide fumarate reductase enzymes on tap. However, they do have two separate versions of the Fp subunit, and produce them both in most tissues. Researchers have found that many cancers including breast, lung and lymphoma preferentially make the type II Fp subunit.Genetic sequencing has revealed that several varieties of tumors, like pheochromocytoma and paraganglioma, are associated wth certain variants of complex II genes. These tumors are also associated with specific assembly factors that help construct and position complex II. Complex II is unique in that all its subunits are encoded in the nucleus. There is still some debate about where and how many complex II units get coordinated into larger respiratory supercomplexesthat can confine the Q and cytochrome C mobile electron carriers. It is now understood that the translation and early assembly of complex III and complex IV occur at the inner membrane boundary while that of complex V takes place deep in the cristae.Today, many new therapies depend on which particular variants you and your tumor happen to have. Before antihelminthic compounds become a standard of care tumor treatments, there are several other important enzyme systems that deal in quinones that may need to be fully investigated. For example, these include quinone biosynthesis enzymes, alternative oxidase, glycerol-3-phosphate dehydrogenase, and dihydroorotate dehydrogenase (DHODH).DHODH is a critical step in de novo pyrimidine biosynthesis and requires complex III to regenerate ubiquinone in order to function. Appreciating these many subtle links between electron transport and synthesis of the fundamental building blocks of life is critical to understanding what cancer is. More information: Courtney W Stairs et al. Microbial eukaryotes have adapted to hypoxia by horizontal acquisitions of a gene involved in rhodoquinone biosynthesis, eLife (2018). DOI: 10.7554/eLife.34292 Photosynthesis involves a protein “piston”
Kolkata: The North 24-Parganas district administration will slap a fine of Rs 1,001 on those who will spit inside the recently inaugurated Dakshineswar skywalk.The decision was taken after it was found that some visitors had spoiled some pillars inside the skywalk by spitting on them. The skywalk, which is the only of its kind in the country, has been constructed at an estimated cost of Rs 60 crore and was inaugurated by Chief Minister Mamata Banerjee on November 5. Also Read – Rain batters Kolkata, cripples normal lifeThe skywalk, having a length of 340 metres and width of 10 metres, will take the devotees straight to Dakshineswar Temple from the main road intersection. During her inaugural speech, Banerjee requested the visitors and the Dakshineswar temple management to keep the skywalk clean. She had instructed the Kamarhati municipality to engage workers under 100 days work, to keep it clean. But unfortunately, within 24 hours of its inauguration, it was found that some people had spit on the pillars. The photograph was uploaded on social media. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThe officials of district administration are informing the people about the penalty through the public address system. The devotees welcomed the move taken up by the district administration and said that more stringent action should be taken against the habitual offenders. They said that those who chew tobacco, have a tendency to spit on walls. Senior officials of the district administration said workers will be posted inside the skywalk, who will request people not to spot on the walls or pillars and maintain it properly.
Kolkata: Police were heckled by BJP supporters across the state after their bike rallies in the name of ‘Sankalpa Yatra’ were stopped due to lack of permission. In multiple places, police personnel were injured after being attacked by BJP supporters.On Sunday, BJP supporters organised multiple bike rallies from various parts of Kolkata. However, as no permission had been taken for the same, police tried to stop the bike rallies. Despite repeated requests to stop, the BJP supporters tried to continue forcefully. Later, forces of Kolkata Police intervened and arrested 135 BJP supporters. 59 bikes were seized as well. Also Read – Bose & Gandhi: More similar than apart, says Sugata BoseApart from Kolkata, the incident also occurred in several districts. On Sunday morning, a bike rally led by Union minister Babul Supriyo commenced from Nuni Mor at Asansol. After the rally reached Amdiha, police stopped the rally. Immediately, the BJP supporters allegedly attacked on-duty police personnel. They resorted to hooliganism and used sticks and bamboos to beat up the police. The officer-in-charge of a local police station was injured in the scuffle. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataMeanwhile, the situation turned worse when police stopped another bike rally at Goaltor in West Midnapore on Sunday. Immediately, police and BJP supporters got involved in a tussle. Soon, some BJP leaders started pelting bricks at the police. A brick hit Uttam Mitra, Deputy Superintendent of Police (DSP), Operations. Five more police personnel including an assistant sub-inspector were also injured. They were rushed to Goaltor Hopsital. Later, several BJP supporters were arrested in connection with the incident. In Birbhum, police stopped another bike rally organised by BJP. Several supporters were detained. Due to intervention by the police, BJP supporters failed to start their ‘illegal’ bike rally at Ashoknagar in North 24-Parganas. They put up a blockade on Jirat Road, which was cleared later. The party allegedly tried to create unrest in the name of their ‘Sankalpa Yatra’ in other states as well.