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Parag Khanna, Author, Connectography: Mapping the Global Network Revolution

geoffiths posted a photo:

Challenge #16 twist something up yourself. Or think of something that is mentally/socially twisted.

Hidden in the flash. posted a photo:

With a lockdown in place it is against the rules for me to go to places I like to shoot, so I though I would try to create a series called Isolated creativity. The series is not intended to be a diary but a way of documenting thoughts and emotions via photography.

I've felt a bit like Pink Rabbit over the passed few day. I'm not fed up and depressed by the lockdown but by the people who think that it's okay to break the rules. By the tabloid media that run stories that convince people it's okay to go out and about, when it Isn't. By the political points scoring that has started to appear in all forms of media.Lastly I fed up with second home owners that have turned up during lockdown and appear to be going out and about most days.

Just like Pink Rabbit I have the blues.

The investigation into the fatal shooting in Brunswick, Georgia, will also look at a neighbor of suspects Gregory and Travis McMichael who recorded video of the incident, authorities said.

Sean Hannity reacts on 'Watters' World' to the Obama administration being caught lying about Russia collusion.

Ousted vaccine expert Rick Bright said he is "frustrated at our inability to be heard as scientists."

Elizabeth Spiers wrote about an incident where Jared Kushner used the memorial of an employee to congratulate himself for success.

GAZIANTEP, Turkey—After five years fighting to preserve Bashar al-Assad’s regime in Syria, Russia now appears inclined to dispose of its infamous client. Assad’s persistent brutality and corruption, and his inability to establish even the semblance of a functioning state, has grown to be a burden Moscow would prefer not to bear.And then there’s the problem of Iran. Assad, members of his family, and his Alawite clansmen enjoy close, perhaps unbreakable, bonds to the regime in Tehran and to Iranian-backed militias in Syria. All of which undermines Moscow’s primary mission there: to rehabilitate the Assad regime as a symbol of stability capable of attracting hundreds of billions of dollars of foreign investment for reconstruction, which Russian firms would then be poised to receive. As long as Assad’s relatives continue to function as a mafia and give free rein to Iranian troops using Syria as base of operations to threaten Israel and plan attacks against U.S. troops in Iraq, those countries likely to foot the bill for Syrian reconstruction—the nations of Europe and the Gulf—are unlikely to come up with the cash. Amid Escalating Syrian Carnage, Turkey Shoots Down Assad’s PlanesThis has not gone unnoticed by the United States.“Assad has done nothing to help the Russians sell this regime,”James Jeffrey, the U.S. special envoy for the Coalition to Defeat ISIS, told reporters in a State Department briefing on Thursday. “You find Assad has nothing but thugs around him, and they don't sell well either in the Arab world or in Europe. We have heard repeatedly from Russians we take as credible that they understand how bad Assad is.” The Syrian president’s “refusal to make any compromises” in order to secure diplomatic recognition and acceptance for his regime has jeopardized “hundreds of billions of dollars in reconstruction assistance” for Syria, according to Jeffrey. Yet the Trump administration is unlikely to exploit this growing rift. “Getting Russia out of Syria,” Jeffrey said, “has never been our goal. Russia has been there for 30 years. It has a long-term relationship with Syria. We don’t think it has been healthy for the region. We don’t think it really is even healthy for Russia. But that’s not our policy.”  MEDIA FRENZYJeffrey’s statements come just one week after Russian state media unleashed a slew of reports and editorials targeting Assad, portraying the beleaguered president as hopelessly corrupt and unfit to govern, and suggesting the time had come to replace him with a new leader.The first batch of articles was published by the Russia’s Federal News Agency (FNA), an outlet owned by Yevgeny Prigozhin, a Russian oligarch and chairman of several companies implicated in the 2016 U.S. elections scandal. Appearing over the course of a mere three hours on April 17, they would shake Syria to its core. The first of the three articles in question highlighted a corruption scheme carried out by the regime in summer 2019 in which the Syrian prime minister purportedly lied to citizens about oil and gas scarcities in order to justify the occurrence of long power outages while selling Syrian electricity to businessmen in Lebanon. The second piece cited an opinion poll claiming only 32 percent of Syrians would vote for Assad in the country’s upcoming 2021 presidential election. The third and final article, entitled, “Corruption is Worse than Terrorism,” chastized President Assad for personally failing to combat corruption, prevalent at all levels of the state.  That these were published by Prigozhin’s news agency was the kind of signal it would be hard for Assad to miss. Prigozhin, who first built his fortune as a caterer, is sometimes known as “Putin’s chef.” But of particular relevance to Syria is his role as chairman of the Wagner Group, whose mercenaries have fought alongside Assad regime forces since October 2015 and helped the latter take back control of key revenue generating infrastructure such as the al-Sha’ir gas field in Homs province.Deputy Assistant Secretary Christopher Robin told the same State Department briefing Thursday, “Wagner is often misleadingly referred to as a Russian private military company, but in fact it’s an instrument of the Russian government which the Kremlin uses as a low-cost and low-risk instrument to advance its goals.”The article on corruption would also point out, suggestively, that the Assads are not the only powerful family in Syria, “there are also the Makhloufs.”Rami Makhlouf, who is in fact Bashar al-Assad’s first cousin, is Syria’s wealthiest man, and also, it would seem, Russia’s man. Certainly he has strong ties to the Kremlin and for years has been one of the most vocal critics of Iran’s presence in Syria. In July 2018, the al-Watan newspaper, one Syria’s most prominent pro-regime mouthpieces and owned by Rami Makhlouf since 2006, published a then unprecedented public rebuke to Iran, accusing it of sponsoring Islamist fanaticism throughout the Middle East alongside Turkey and Qatar, the main backers of Syria’s opposition. (Rami Makhlouf’s father Muhammad and brother Hafiz meanwhile are alleged by some to be living in Russia.) The April 17 articles published by Prigozhin’s FNA preceded the release of a wave of other articles and items in the media over the next 12 days that would further drive home the point that Moscow was considering options other than Assad to rule Syria. TASS, Russia’s largest state-run news agency, wrote in one editorial that, “Russia suspects that Assad is not only unable to lead the country anymore, but also that the head of the Syrian regime is dragging Moscow towards the Afghani scenario.” This is like evoking the Vietnam War for an American audience, a reference to the Kremlin’s botched campaign through the 1980s that helped bankrupt the Soviet Union and finally break it apart.Amid this coverage, TASS would also take swipes at Iran, claiming that the Islamic Republic has “no interest in achieving stability in the region, because it considers it a battlefield with Washington”.On April 30, the Russian International Affairs Council (RIAC), a think tank established by Moscow’s Ministry of Foreign Affairs, released a scathing report saying Russia was in talks with other parties to the Syrian conflict to draw up plans for a political resolution that did not include Bashar al-Assad as president. The report highlighted purported Russian efforts to compel the Syrian regime to commit to ceasefires with both American-backed and Kurdish-led Syrian Democratic Forces (SDF), and the Turkish-backed Free Syrian Army (FSA) opposition, while beginning steps to form a new unity government that would include representatives from both. That day, Rami Makhlouf, whose assets were frozen five months earlier as part of a tax dispute, uploaded a video onto his personal Facebook page accusing the Assad regime of corruption. In a state known for carrying out the full-scale slaughter of those who test its authority, Makhlouf’s videos, coming on the heels of the unprecedented Russian attacks in the media, sent shockwaves throughout the country.  THE ROYAL FAMILYWhile the Makhlouf clan clearly has thrown its lot in with Russia, key members of Bashar al-Assad’s immediate family and others with ties to Qardaha in Syria’s largely Alawite Latakia province, are among the most prominent Iranian-backed militia leaders in Syria. It’s an alliance that traces back to his father Hafez al-Assad, who was born in Qardaha, and who forged ties with the Iranian revolution almost from its beginning more than 40 years ago. The Iranians responded by offering religious legitimacy to the Alawite sect, which is regarded as heretical by Sunnis and indeed by many Shi’a.These Qardaha militia leaders have regularly engaged in armed clashes against Russian backed units. They are among the most egregious violators and abusers of power, overseeing wide networks of corruption similar to those lamented in the Russian media. And foremost among them is Bashar’s younger brother, Maher al-Assad. Since April 2018, Maher al-Assad has commanded the Syrian Army’s 4th Armored Division, one of country’s oldest, best equipped and overwhelmingly Alawite brigades. After the 2011 outbreak of the Syrian revolution, when the loyalty of much of the army was in doubt, it became a refuge for numerous Alawite-Shi’a dominated pro-regime militias.Currently, the 4th Armored Division’s members control many smuggling operations throughout the country, in cities from Albu Kamel on Syria’s eastern border with Iraq to Latakia on the Syrian coast, where the port was leased to Iran on October 1 last year. It has since become one of the biggest export hubs for drugs headed to markets in Europe, the Middle East and North Africa. Examples abound: On July 5, 2019, Greek coast guard and drug enforcement officials announced the biggest drug bust in history, seizing 5.25 tons (33 million pills) of Captagon amphetamines worth $660m hidden in shipping containers loaded at the Latakia port in Syria. That followed a long string of such seizures made by Greek authorities. More recently, in late April, customs officials in both Saudi Arabia and Egypt also announced the seizure of similar quantities of drugs in containers traced back to Latakia. Local reports have accused a range of actors including Maher al-Assad’s 4th Division, Hizbollah, Rami Makhlouf, and others of profiting from the massive drug exports emanating from the port. In January 2019 the 4th Armored Division launched attacks on the Russian-backed Tiger Forces unit in an attempt to wrest control of smuggling routes between regime- and opposition-held territory in Idlib province. The clashes led to the death of 70 fighters. These and other skirmishes prompted Russia to back a major campaign to arrest 4th Division and other Iranian-backed units throughout the country beginning in April 2019, which succeeded in rounding up numerous mid-ranking Iranian-backed officers. Among those targeted in the campaign was Bashar Talal al-Assad, a cousin to the president (similar name, different people) who was wanted on drug and weapons trafficking charges. Unlike others who were detained in the roundup, Bashar Talal al-Assad and his ‘Areen Brigade managed to fight off Russian-backed forces that sought to arrest him in Qardaha. He then pledged to attack Russia’s Hmeimim military base, located 17 miles east of Latakia city, in the event the regime sought to arrest him again.For Russia, the threat of such attacks on its military infrastructure is a real concern. The Hmeimim base—from which Moscow has directed its entire military campaign in Syria—had already been subject to a series of attacks from January to October 2018 by other Iranian-backed militias in the area. The threat posed by both Iran’s acquisition of the Latakia port and its support for local Assad family proxies in Syria’s coastal region is exacerbated by the fact that Tehran has also begun making progress toward completing construction of its Shalamcha railroad, which, via stops in Basra, Baghdad, Albu Kamel and Damascus, will give Tehran direct access to the Syrian and Lebanese coasts. If Iran succeeds in integrating the Latakia port with the Shalamcha rail line, this will cut off Hmeimim from Russian forces in central and southern Syria and enable Tehran to quickly deliver weapons to proxy forces in Latakia that are already engaged in clashes against Russian-backed groups. WORLDWIDE CONSENSUSMoscow’s inability to control Iranian backed Syrian militiamen engaged in widespread crime, corruption, and assaults on Russian forces has infuriated the Kremlin. But Russia is not the only major player on the ground with scores to settle against Iran, and the Russian military leadership in Syria has ignored if not largely encouraged Israeli strikes on Iranian troops throughout the country.It may not be coincidental that the Israeli attacks have increased in pace and scope since April, following the flurry of Russian media articles attacking Assad and his regime. “We have moved from blocking Iran’s entrenchment in Syria to forcing it out of there, and we will not stop,” Israel’s new defense minister, Naftali Bennett, declared on April 28. Without Russia, Iran has found itself the odd man out in Syria, the single party still seeking to push for war at a time when most other international players have been struck with fatigue and simply seek to put Syria’s pieces back together. President Recep Tayyip Erdoğan of Turkey, the last patron of Syria’s battered FSA opposition, has himself made peace with Moscow, effectively agreeing last March to cede control of wide swaths of rebel held territory after a particularly bloody Russian led campaign against the last FSA holdout in Idlib province that ended in victory for regime forces. Ironically, Erdoğan’s long-held desire to overthrow Syria’s president may still come to fruition, albeit not as he expected, as Assad’s ouster may come at the hands of Russia itself, and not the revolution. Read more at The Daily Beast.Get our top stories in your inbox every day. Sign up now!Daily Beast Membership: Beast Inside goes deeper on the stories that matter to you. Learn more.

Whenever Americans see videos of police brutality against black men and women, the first thing they do is assume they deserved their executionWhat skin color are the bad guys in America’s fantasies of vigilantism? When the proverbial “fellas” get together to drink beers and talk about their newest guns and who they’d take down, what race are the “criminals” in the theater of their minds?When Greg McMichael and his son, Travis, got the call from their neighbor that a “burglar” was running through their Brunswick, Georgia neighborhood that chilly February day, what color man do you think they imagined as they locked, loaded, and embarked on their “mission”?Ahmaud Arbery is dead today because when Americans dream of vigilante justice, black men are the villains of their imaginations.We as a nation are so comfortable with this baseline bigotry that our first assumption whenever we see videos of police brutality against or shootings of black men and women, the first thing we do is assume that the victims must have done something wrong to earn their own public execution.This assumption is both a function of white America having a completely different experience with police officers than black America as well as the hundreds of years of vilifying blackness in media and American culture.I will never forget the biggest and most uproarious applause during the theater debut of the lackluster 2007 vigilante film, Brave One, came when the protagonist Jodi Foster got her first vigilante kills of the movie – two threatening and scary black men. That theater filled with men the same age range as Greg and Travis McMichael erupted as if at that moment, all that they had ever imagined had been fulfilled on the big screen. Needless to say, I left that theater before the credits rolled.Across the country, our political leaders hold these same bigoted beliefs which inevitably lead to policies that directly assume criminality based on skin color.During his tenure as mayor of New York City, billionaire Michael Bloomberg made it explicitly clear why it was that he sent police officers into black and brown communities to “throw them” up against the wall. In his 2015 Aspen Institute speech he stated:“People say, ‘Oh my God, you are arresting kids for marijuana who are all minorities.’ Yes, that’s true. Why? Because we put all the cops in the minority neighborhoods. Yes, that’s true. Why’d we do it? Because that’s where all the crime is. And the way you should get the guns out of the kids’ hands is throw them against the wall and frisk them.”And it is for this reason that I do not distinguish between the violence committed by American citizens acting as vigilantes and the violence committed by so-called officers of the law when, in both cases, the working assumption and driving force behind that violence is the deeply bigoted and firmly American association between blackness and criminality.For Ahmaud, that association not only led to his brutal killing, but it also initially meant his killer not being arrested. It took more than two months for the father and son duo to be arrested. When explaining why they were not charged immediately the district attorney, George Barnhill, immediately stated that the victim, Ahmaud Arbery, was, in fact, the “criminal suspect”.“It appears that [Greg and Travis McMichael’s] intent was to stop and hold this criminal suspect until law enforcement arrived. Under Georgia Law [sic] this is perfectly legal.”Even after viewing the video and with no evidence beyond Ahmaud’s skin color, the top cop in the institution designed to bring equal justice under the law concluded that Ahmaud was a criminal suspect when he was simply a black man taking a jog.What are black Americans to do when justice is delayed or outright denied because of the assignment of innocence to vigilantes and police officers?What are black Americans to do when the assumption of guilt because of our skin color is as American as the guns they use to kill us?What are we to do when in our neighbors’ dreams and fantasies of cop-and-robber, the skin color of the bad guy matches our own?The very first thing we are going to do is defend ourselves as if our lives depend on it because when Americans fantasize about killing, those fantasies become our living nightmares. * Benjamin Dixon is the host of the Benjamin Dixon show.

Representative Michael McCaul, who has harshly criticized China in his position as the ranking member on the House Foreign Affairs Committee, disclosed that his family owns stock in a Chinese tech company he described as a threat to national security.An April 20 periodic transaction report showed that McCaul disclosed a February purchase of between $50,000 and $100,000 in shares of the Chinese firm Tencent Holdings, Politico reported.In November, several months before the shares were purchased, the Texas congressman said that Tencent Holdings is among the "Chinese companies that threaten America’s economic and national security."The tech conglomerate is "heavily involved" in the "social credit system, a dystopian system China has implemented to score its citizens’ behavior," McCaul said at the time, as well as an "integral part" of the Chinese Communist Party’s industrial policies and "one of four national champions for artificial intelligence."McCaul's lawyer, Elliot Berke, said that the shares are not owned personally by McCaul but by his wife, and the decision to invest in Tencent was made by a third party.“Congressman McCaul did not purchase any shares in China’s Tencent Holdings or any other Chinese company,” the attorney said. “Congressman McCaul’s wife has assets she solely owns and a third party manager made the purchase without her direction.”Rachel Walker, a spokeswoman for McCaul, emphasized that the revelation of the Tencent shares “highlights that many Americans unwittingly invest their money in Chinese owned companies."Federal employees are often unaware they own such investments because the federal government’s thrift savings plan program creates portfolios that include Tencent and other Chinese companies, Walker said. McCaul has argued that such retirement investment plans should not invest American dollars in such "shady" Chinese companies, often without the knowledge of the investor."Congressman McCaul has been a fierce critic of the brutal behavior of the Chinese Communist Party and will continue to fight to hold them accountable as the Chair of the China Task Force," Walker said. "This should be a wake-up call to us all that the CCP’s involvement in the U.S. economy is far more reaching than many Americans realize and that we need to change the way we do business with China, including our investments."Tencent owns the Chinese social media platform WeChat, which has more than one billion users and is suspected of monitoring the activities of users both inside and outside of China. Tencent is also associated with Chinese tech firm Huawei, which U.S. officials said can secretly access American cellular phone networks, giving it access to sensitive information.McCaul has taken a leading role in criticizing China's handling of the coronavirus pandemic as well, accusing Beijing of launching perhaps the "worst cover-up in human history."He was tapped on Thursday by House Minority Leader Kevin McCarthy as chairman of the China Task Force, the aim of which is to develop "legislative solutions to address the Chinese Communist Party’s malign global agenda."The task force will "develop new and enduring policy solutions that, among others, enhance our economic strength and create jobs, protect our national security, rethink our supply chains and grow our competitive edge in technology," McCaul said in a statement on his appointment.

Nepal protested India's inauguration of a new road to China that passes through territory claimed by Kathmandu on Saturday, with police arresting dozens demonstrating close to India's embassy. Indian defence minister Rajnath Singh on Friday inaugurated via video link the 80-kilometre (50 miles) long road from Ghatiabagarh in northern Uttarakhand state to the Lipu Lekh pass high in the Himalaya. The pass is claimed by Nepal based on an 1816 treaty that defines its western border with India.

The government said it's distributing the promising coronavirus drug, remdesivir, to some hard-hit states. Eventually, all 50 states should get it.

Shelling of Tripoli's Mitiga airport early on Saturday, part of an intensified barrage of artillery fire on the capital in recent days, hit fuel tanks and damaged passenger planes, the Transport Ministry said in a statement. Mitiga is the last functioning airport in the Libyan capital, though civilian flights stopped in March because of repeated shelling even before the country imposed a lockdown over the coronavirus pandemic. Brega Petroleum Marketing Company, part of the National Oil Corporation, said its jet fuel tanks at Mitiga caught fire after coming under attack and firemen were working to control the blaze.

Pakistanis crowded markets on Saturday after a nationwide coronavirus lockdown was eased, despite the country declaring its second highest daily infection toll. Prime Minister Imran Khan has allowed businesses to reopen in phases from the weekend, citing the economic havoc the virus restrictions have wreaked on the improvised nation. In the garrison city of Rawalpindi, thousands of shoppers were preparing for Eid, which follows the Muslim fasting month of Ramadan, with many flouting social distancing rules and advice to wear masks.

President Trump said Friday he had watched the video of Ahmaud Arbery being shot and found it “very disturbing” and “heartbreaking,” but said he was confident that the Georgia legal system would come down on the side of justice.

Travel blogger and photographer Andy Luten drove 4,200 miles across six states to see the grounded jets, detailing the shocking state of aviation.

Lethal infections by strains of the highly-pathogenic avian influenza virus (HPAIV) H5N1 pose serious threats to both the poultry industry and public health worldwide. A lack of confirmed HPAIV epitopes recognized by cytotoxic T lymphocytes (CTLs) has hindered the utilization of CD8+ T-cell–mediated immunity and has precluded the development of effectively diversified epitope-based vaccination approaches. In particular, an HPAIV H5N1 CTL-recognized epitope based on the peptide MHC-I–β2m (pMHC-I) complex has not yet been designed. Here, screening a collection of selected peptides of several HPAIV strains against a specific pathogen-free pMHC-I (pBF2*1501), we identified a highly-conserved HPAIV H5N1 CTL epitope, named HPAIV–PA123–130. We determined the structure of the BF2*1501–PA123–130 complex at 2.1 Å resolution to elucidate the molecular mechanisms of a preferential presentation of the highly-conserved PA123–130 epitope in the chicken B15 lineage. Conformational characteristics of the PA123–130 epitope with a protruding Tyr-7 residue indicated that this epitope has great potential to be recognized by specific TCRs. Moreover, significantly increased numbers of CD8+ T cells specific for the HPAIV–PA123–130 epitope in peptide-immunized chickens indicated that a repertoire of CD8+ T cells can specifically respond to this epitope. We anticipate that the identification and structural characterization of the PA123–130 epitope reported here could enable further studies of CTL immunity against HPAIV H5N1. Such studies may aid in the development of vaccine development strategies using well-conserved internal viral antigens in chickens.

Protease-activated receptor 2 (PAR-2) is activated by secreted proteases from immune cells or fungi. PAR-2 is normally expressed basolaterally in differentiated nasal ciliated cells. We hypothesized that epithelial remodeling during diseases characterized by cilial loss and squamous metaplasia may alter PAR-2 polarization. Here, using a fluorescent arrestin assay, we confirmed that the common fungal airway pathogen Aspergillus fumigatus activates heterologously-expressed PAR-2. Endogenous PAR-2 activation in submerged airway RPMI 2650 or NCI–H520 squamous cells increased intracellular calcium levels and granulocyte macrophage–colony-stimulating factor, tumor necrosis factor α, and interleukin (IL)-6 secretion. RPMI 2650 cells cultured at an air–liquid interface (ALI) responded to apically or basolaterally applied PAR-2 agonists. However, well-differentiated primary nasal epithelial ALIs responded only to basolateral PAR-2 stimulation, indicated by calcium elevation, increased cilia beat frequency, and increased fluid and cytokine secretion. We exposed primary cells to disease-related modifiers that alter epithelial morphology, including IL-13, cigarette smoke condensate, and retinoic acid deficiency, at concentrations and times that altered epithelial morphology without causing breakdown of the epithelial barrier to model early disease states. These altered primary cultures responded to both apical and basolateral PAR-2 stimulation. Imaging nasal polyps and control middle turbinate explants, we found that nasal polyps, but not turbinates, exhibit apical calcium responses to PAR-2 stimulation. However, isolated ciliated cells from both polyps and turbinates maintained basolateral PAR-2 polarization, suggesting that the calcium responses originated from nonciliated cells. Altered PAR-2 polarization in disease-remodeled epithelia may enhance apical responses and increase sensitivity to inhaled proteases.

Extracytoplasmic sugar decoration of glycopolymer components of the bacterial cell wall contributes to their structural diversity. Typically, the molecular mechanism that underpins such a decoration process involves a three-component glycosylation system (TGS) represented by an undecaprenyl-phosphate (Und-P) sugar-activating glycosyltransferase (Und-P GT), a flippase, and a polytopic glycosyltransferase (PolM GT) dedicated to attaching sugar residues to a specific glycopolymer. Here, using bioinformatic analyses, CRISPR-assisted recombineering, structural analysis of cell wall–associated polysaccharides (CWPS) through MALDI-TOF MS and methylation analysis, we report on three such systems in the bacterium Lactococcus lactis. On the basis of sequence similarities, we first identified three gene pairs, csdAB, csdCD, and csdEF, each encoding an Und-P GT and a PolM GT, as potential TGS component candidates. Our experimental results show that csdAB and csdCD are involved in Glc side-chain addition on the CWPS components rhamnan and polysaccharide pellicle (PSP), respectively, whereas csdEF plays a role in galactosylation of lipoteichoic acid (LTA). We also identified a potential flippase encoded in the L. lactis genome (llnz_02975, cflA) and confirmed that it participates in the glycosylation of the three cell wall glycopolymers rhamnan, PSP, and LTA, thus indicating that its function is shared by the three TGSs. Finally, we observed that glucosylation of both rhamnan and PSP can increase resistance to bacteriophage predation and that LTA galactosylation alters L. lactis resistance to bacteriocin.

Prevention of aberrant cutaneous wound repair and appropriate regeneration of an intact and functional integument require the coordinated timing of fibroblast and keratinocyte migration. Here, we identified a mechanism whereby opposing cell-specific motogenic functions of a multifunctional intracellular and extracellular protein, the receptor for hyaluronan-mediated motility (RHAMM), coordinates fibroblast and keratinocyte migration speed and ensures appropriate timing of excisional wound closure. We found that, unlike in WT mice, in Rhamm-null mice, keratinocyte migration initiates prematurely in the excisional wounds, resulting in wounds that have re-surfaced before the formation of normal granulation tissue, leading to a defective epidermal architecture. We also noted aberrant keratinocyte and fibroblast migration in the Rhamm-null mice, indicating that RHAMM suppresses keratinocyte motility but increases fibroblast motility. This cell context–dependent effect resulted from cell-specific regulation of extracellular signal-regulated kinase 1/2 (ERK1/2) activation and expression of a RHAMM target gene encoding matrix metalloprotease 9 (MMP-9). In fibroblasts, RHAMM promoted ERK1/2 activation and MMP-9 expression, whereas in keratinocytes, RHAMM suppressed these activities. In keratinocytes, loss of RHAMM function or expression promoted epidermal growth factor receptor–regulated MMP-9 expression via ERK1/2, which resulted in cleavage of the ectodomain of the RHAMM partner protein CD44 and thereby increased keratinocyte motility. These results identify RHAMM as a key factor that integrates the timing of wound repair by controlling cell migration.

Actinobacillus pleuropneumoniae (App) is the etiological agent of acute porcine pneumonia and responsible for severe economic losses worldwide. The capsule polymer of App serotype 1 (App1) consists of [4)-GlcNAc-β(1,6)-Gal-α-1-(PO4-] repeating units that are O-acetylated at O-6 of the GlcNAc. It is a major virulence factor and was used in previous studies in the successful generation of an experimental glycoconjugate vaccine. However, the application of glycoconjugate vaccines in the animal health sector is limited, presumably because of the high costs associated with harvesting the polymer from pathogen culture. Consequently, here we exploited the capsule polymerase Cps1B of App1 as an in vitro synthesis tool and an alternative for capsule polymer provision. Cps1B consists of two catalytic domains, as well as a domain rich in tetratricopeptide repeats (TPRs). We compared the elongation mechanism of Cps1B with that of a ΔTPR truncation (Cps1B-ΔTPR). Interestingly, the product profiles displayed by Cps1B suggested processive elongation of the nascent polymer, whereas Cps1B-ΔTPR appeared to work in a more distributive manner. The dispersity of the synthesized products could be reduced by generating single-action transferases and immobilizing them on individual columns, separating the two catalytic activities. Furthermore, we identified the O-acetyltransferase Cps1D of App1 and used it to modify the polymers produced by Cps1B. Two-dimensional NMR analyses of the products revealed O-acetylation levels identical to those of polymer harvested from App1 culture supernatants. In conclusion, we have established a protocol for the pathogen-free in vitro synthesis of tailored, nature-identical App1 capsule polymers.

Lens proteins become increasingly cross-linked through nondisulfide linkages during aging and cataract formation. One mechanism that has been implicated in this cross-linking is glycation through formation of advanced glycation end products (AGEs). Here, we found an age-associated increase in stiffness in human lenses that was directly correlated with levels of protein–cross-linking AGEs. α-Crystallin in the lens binds to other proteins and prevents their denaturation and aggregation through its chaperone-like activity. Using a FRET-based assay, we examined the stability of the αA-crystallin–γD-crystallin complex for up to 12 days and observed that this complex is stable in PBS and upon incubation with human lens–epithelial cell lysate or lens homogenate. Addition of 2 mm ATP to the lysate or homogenate did not decrease the stability of the complex. We also generated complexes of human αA-crystallin or αB-crystallin with alcohol dehydrogenase or citrate synthase by applying thermal stress. Upon glycation under physiological conditions, the chaperone–client complexes underwent greater extents of cross-linking than did uncomplexed protein mixtures. LC-MS/MS analyses revealed that the levels of cross-linking AGEs were significantly higher in the glycated chaperone–client complexes than in glycated but uncomplexed protein mixtures. Mouse lenses subjected to thermal stress followed by glycation lost resilience more extensively than lenses subjected to thermal stress or glycation alone, and this loss was accompanied by higher protein cross-linking and higher cross-linking AGE levels. These results uncover a protein cross-linking mechanism in the lens and suggest that AGE-mediated cross-linking of α-crystallin–client complexes could contribute to lens aging and presbyopia.

The dextransucrase DSR-OK from the Gram-positive bacterium Oenococcus kitaharae DSM17330 produces a dextran of the highest molar mass reported to date (∼109 g/mol). In this study, we selected a recombinant form, DSR-OKΔ1, to identify molecular determinants involved in the sugar polymerization mechanism and that confer its ability to produce a very-high-molar-mass polymer. In domain V of DSR-OK, we identified seven putative sugar-binding pockets characteristic of glycoside hydrolase 70 (GH70) glucansucrases that are known to be involved in glucan binding. We investigated their role in polymer synthesis through several approaches, including monitoring of dextran synthesis, affinity assays, sugar binding pocket deletions, site-directed mutagenesis, and construction of chimeric enzymes. Substitution of only two stacking aromatic residues in two consecutive sugar-binding pockets (variant DSR-OKΔ1-Y1162A-F1228A) induced quasi-complete loss of very-high-molar-mass dextran synthesis, resulting in production of only 10–13 kg/mol polymers. Moreover, the double mutation completely switched the semiprocessive mode of DSR-OKΔ1 toward a distributive one, highlighting the strong influence of these pockets on enzyme processivity. Finally, the position of each pocket relative to the active site also appeared to be important for polymer elongation. We propose that sugar-binding pockets spatially closer to the catalytic domain play a major role in the control of processivity. A deep structural characterization, if possible with large-molar-mass sugar ligands, would allow confirming this hypothesis.

Bacterial biofilms are cellular communities that produce an adherent matrix. Exopolysaccharides are key structural components of this matrix and are required for the assembly and architecture of biofilms produced by a wide variety of microorganisms. The human bacterial pathogens Escherichia coli and Salmonella enterica produce a biofilm matrix composed primarily of the exopolysaccharide phosphoethanolamine (pEtN) cellulose. Once thought to be composed of only underivatized cellulose, the pEtN modification present in these matrices has been implicated in the overall architecture and integrity of the biofilm. However, an understanding of the mechanism underlying pEtN derivatization of the cellulose exopolysaccharide remains elusive. The bacterial cellulose synthase subunit G (BcsG) is a predicted inner membrane–localized metalloenzyme that has been proposed to catalyze the transfer of the pEtN group from membrane phospholipids to cellulose. Here we present evidence that the C-terminal domain of BcsG from E. coli (EcBcsGΔN) functions as a phosphoethanolamine transferase in vitro with substrate preference for cellulosic materials. Structural characterization of EcBcsGΔN revealed that it belongs to the alkaline phosphatase superfamily, contains a Zn2+ ion at its active center, and is structurally similar to characterized enzymes that confer colistin resistance in Gram-negative bacteria. Informed by our structural studies, we present a functional complementation experiment in E. coli AR3110, indicating that the activity of the BcsG C-terminal domain is essential for integrity of the pellicular biofilm. Furthermore, our results established a similar but distinct active-site architecture and catalytic mechanism shared between BcsG and the colistin resistance enzymes.

Fucosylation of the innermost GlcNAc of N-glycans by fucosyltransferase 8 (FUT8) is an important step in the maturation of complex and hybrid N-glycans. This simple modification can dramatically affect the activities and half-lives of glycoproteins, effects that are relevant to understanding the invasiveness of some cancers, development of mAb therapeutics, and the etiology of a congenital glycosylation disorder. The acceptor substrate preferences of FUT8 are well-characterized and provide a framework for understanding N-glycan maturation in the Golgi; however, the structural basis of these substrate preferences and the mechanism through which catalysis is achieved remain unknown. Here we describe several structures of mouse and human FUT8 in the apo state and in complex with GDP, a mimic of the donor substrate, and with a glycopeptide acceptor substrate at 1.80–2.50 Å resolution. These structures provide insights into a unique conformational change associated with donor substrate binding, common strategies employed by fucosyltransferases to coordinate GDP, features that define acceptor substrate preferences, and a likely mechanism for enzyme catalysis. Together with molecular dynamics simulations, the structures also revealed how FUT8 dimerization plays an important role in defining the acceptor substrate-binding site. Collectively, this information significantly builds on our understanding of the core fucosylation process.

Multidrug resistance (MDR) in cancer arises from cross-resistance to structurally- and functionally-divergent chemotherapeutic drugs. In particular, MDR is characterized by increased expression and activity of ATP-binding cassette (ABC) superfamily transporters. Sphingolipids are substrates of ABC proteins in cell signaling, membrane biosynthesis, and inflammation, for example, and their products can favor cancer progression. Glucosylceramide (GlcCer) is a ubiquitous glycosphingolipid (GSL) generated by glucosylceramide synthase, a key regulatory enzyme encoded by the UDP-glucose ceramide glucosyltransferase (UGCG) gene. Stressed cells increase de novo biosynthesis of ceramides, which return to sub-toxic levels after UGCG mediates incorporation into GlcCer. Given that cancer cells seem to mobilize UGCG and have increased GSL content for ceramide clearance, which ultimately contributes to chemotherapy failure, here we investigated how inhibition of GSL biosynthesis affects the MDR phenotype of chronic myeloid leukemias. We found that MDR is associated with higher UGCG expression and with a complex GSL profile. UGCG inhibition with the ceramide analog d-threo-1-(3,4,-ethylenedioxy)phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (EtDO-P4) greatly reduced GSL and monosialotetrahexosylganglioside levels, and co-treatment with standard chemotherapeutics sensitized cells to mitochondrial membrane potential loss and apoptosis. ABC subfamily B member 1 (ABCB1) expression was reduced, and ABCC-mediated efflux activity was modulated by competition with nonglycosylated ceramides. Consistently, inhibition of ABCC-mediated transport reduced the efflux of exogenous C6-ceramide. Overall, UGCG inhibition impaired the malignant glycophenotype of MDR leukemias, which typically overcomes drug resistance through distinct mechanisms. This work sheds light on the involvement of GSL in chemotherapy failure, and its findings suggest that targeted GSL modulation could help manage MDR leukemias.