Showing posts with label Virology. Show all posts
Showing posts with label Virology. Show all posts

Thursday, August 18, 2022

UBC researchers discover ‘weak spot’ across major COVID-19 variants

Cryo-electron microscopy reveals how the VH Ab6 antibody fragment (red) attaches to the vulnerable site on the SARS-CoV-2 spike protein (grey) to block the virus from binding with the human ACE2 cell receptor (blue).
Credit: Dr. Sriram Subramaniam, UBC

Researchers at the University of British Columbia have discovered a key vulnerability across all major variants of the SARS-CoV-2 virus, including the recently emerged BA.1 and BA.2 Omicron subvariants.

The weakness can be targeted by neutralizing antibodies, potentially paving the way for treatments that would be universally effective across variants.

The findings, published today in Nature Communications, use cryo-electron microscopy (cryo-EM) to reveal the atomic-level structure of the vulnerable spot on the virus’ spike protein, known as an epitope. The paper further describes an antibody fragment called VH Ab6 that is able to attach to this site and neutralize each major variant.

“This is a highly adaptable virus that has evolved to evade most existing antibody treatments, as well as much of the immunity conferred by vaccines and natural infection,” says Dr. Sriram Subramaniam (he/him), a professor at UBC’s faculty of medicine and the study’s senior author. “This study reveals a weak spot that is largely unchanged across variants and can be neutralized by an antibody fragment. It sets the stage for the design of pan-variant treatments that could potentially help a lot of vulnerable people.”

Wednesday, August 17, 2022

First Structure of Key COVID Enzyme at Human Body Temperature

Scientists used x-rays to decipher the three-dimensional structure of the main protease of the virus that causes COVID-19 at different temperatures. The background image shows the full structure at 240 Kelvin (-28°F, cyan stick figure) and 100 K (-280°F, dark blue). The red and green blobs represent differences in the structure at these distinct temperatures. The study allowed the scientists to zero in on subtle shifts that occur in the structure as the temperature changes (inset), potentially pointing to areas of the enzyme that could be targeted with inhibitor drugs to impair its function.
 Source/Credit: Brookhaven National Laboratory

Daniel Keedy, City University of New York
Scientists studying a COVID-19 coronavirus enzyme at temperatures ranging from frosty to human-body warm discovered subtle structural shifts that offer clues about how the enzyme works. The findings, published in IUCrJ, the journal of the International Union of Crystallography, may inspire the design of new drugs to counteract COVID-19—and possibly help head off future coronavirus pandemics.

“No previous study has looked at this important coronavirus enzyme at physiological (or body) temperature,” said Daniel Keedy, a structural biologist at the City University of New York (CUNY), who conducted the study in collaboration with scientists at the U.S. Department of Energy’s Brookhaven National Laboratory.

Most structures to date come from frozen samples—far from the temperatures at which the molecules operate within living cells. “If you are working at physiological temperature, you should get a more realistic picture of what’s happening during an actual infection, because that’s where biology happens,” Keedy said.

In addition, he added, the team used temperature as a tool. “By turning that knob and seeing how the protein reacts, we can learn about its mechanics—how it physically works."

How hepatitis E outwits the immune system

Daniel Todt, Eike Steinmann and Toni Meister (from left) look at the image of a cell infected with the hepatitis E virus. The capsid protein can be seen in green, the cell nucleus in blue.
Credit: Department of Molecular and Medical Virology

Faulty virus particles could be a deception to distract the immune system from fighting infectious viruses.

Over three million people become infected with the hepatitis E virus every year. So far there is no specifically effective drug. An international research team has examined which factors are important for the virus in the course of its reproductive cycle and how it manages to maintain the infection. The researchers analyzed various mutations in the virus and found changes that may allow the virus to outsmart the immune system. The team from the Molecular and Medical Virology Department of the Ruhr University Bochum around Dr. Toni Meister, Dr. Daniel Todt and Prof. Dr. Eike Steinmann reports in the journal PNAS.

Advantages and disadvantages of mutations

An important defense mechanism against viral infections in our body are special proteins, the antibodies. These usually bind specifically to surface proteins of the virus in order to make it harmless. But viruses have developed strategies to avoid this identification. During infection with the hepatitis E virus, random mutations often result in virus variants that can coexist within an infected person. The antiviral agent ribavirin, which many chronically infected people receive, can even increase the formation of such viral variants.

Monday, August 15, 2022

Road signs for immune defense cells

The mechanism of MHC I assembly, epitope editing and quality control within the peptide loading complex (PLC). The fully assembled PLC machinery of antigen processing is formed by the antigen transport complex TAP1/2, the chaperones calreticulin, ERp57, and tapasin, and the heterodimeric MHC I (heavy and light chain in teal and green, respectively).
Credit: Christoph Thomas & Robert Tampé

How do killer T cells recognize cells in the body that have been infected by viruses? Matter foreign to the body is presented on the surface of these cells as antigens that act as a kind of road sign. A network of accessory proteins – the chaperones – ensure that this sign retains its stability over time. Researchers at Goethe University have now reached a comprehensive understanding of this essential cellular quality control process. Their account of the structural and mechanistic basis of chaperone networks has just appeared in the prestigious science journal Nature Communications. These new findings could be harbingers of progress in areas such as vaccine development.

Organisms are constantly invaded by pathogens such as viruses. Our immune system swings into action to combat these pathogens immediately. The innate non-specific immune response is triggered first, and the adaptive or acquired immune response follows. In this second defense reaction, specialized cytotoxic T lymphocytes known as killer T cells destroy cells in the body that have been infected and thus prevent damage from spreading. Humans possess a repertoire of some 20 million T cell clones with varying specificity to counter the multitude of infectious agents that exist. But how do the killer T cells know where danger is coming from? How do they recognize that something is wrong inside a cell in which viruses are lurking? They can't just have a quick peek inside.

Thursday, August 11, 2022

World first chronic fatigue syndrome findings could fast track response to Long COVID

Professor Sonya Marshall-Gradisnik from the National Centre for Neuroimmunology and Emerging Diseases (NCNED) at Griffith University.
Credit: Griffith University

Griffith University researchers are hoping to find a treatment for Long COVID after proving the illness shares the same biological impairment as patients with Chronic Fatigue Syndrome (known internationally as Myalgic Encephalomyelitis (ME/CFS)).

In a world first, their study suggests COVID-19 could be a potential trigger for ME/CFS and their 10 years of research on ME/CFS could help fast track understanding and treatment of Long Covid.

Griffith University’s National Centre for Neuroimmunology and Emerging Diseases Director, Professor Sonya Marshall-Gradisnik, said the breakthrough findings will assist with investigations into therapeutic strategies to help both Long COVID and ME/CFS patients.

“Patients with Long COVID report neurocognitive, immunological, gastrointestinal, and cardiovascular manifestations, which are also symptoms of ME/CFS,” Professor Marshall-Gradisnik said.

“Our researchers have pioneered a specialized technique known as electrophysiology or ‘patch-clamp’ in immune cells.”

“This technique previously led the team to report on the pathology of ME/CFS and to examine specific ion channels in cells.

Monday, August 8, 2022

New inhaled COVID-19 therapeutic blocks viral replication in the lungs

UC Berkeley postdoctoral scholar Chi Zhu is part of a team of researchers who are developing a new COVID-19 therapeutic that can be administered as a nasal spray. The experimental treatment is effective against all SARS-CoV-2 “variants of concern” and could be readily modified to target other RNA viruses.
UC Berkeley photo by Brittany Hosea-Small

Scientists at the University of California, Berkeley, have created a new COVID-19 therapeutic that could one day make treating SARS-CoV-2 infections as easy as using a nasal spray for allergies.

The therapeutic uses short snippets of synthetic DNA to gum up the genetic machinery that allows SARS-CoV-2 to replicate within the body.

In a new study published online in the journal Nature Communications, the team shows that these short snippets, called antisense oligonucleotides (ASOs), are highly effective at preventing the virus from replicating in human cells. When administered in the nose, these ASOs are also effective at preventing and treating COVID-19 infection in mice and hamsters.

“Vaccines are making a huge difference, but vaccines are not universal, and there is still a tremendous need for other approaches,” said Anders Näär, a professor of metabolic biology in the Department of Nutritional Sciences and Toxicology (NST) at UC Berkeley and senior author of the paper. “A nasal spray that is cheaply available everywhere and that could prevent someone from getting infected or prevent serious disease could be immensely helpful.”

Because the ASO treatment targets a portion of the viral genome that is highly conserved among different variants, it is effective against all SARS-CoV-2 “variants of concern” in human cells and in animal models. It is also chemically stable and relatively inexpensive to produce at large scale, making it ideal for treating COVID-19 infections in areas of the world that do not have access to electricity or refrigeration.

Monday, August 1, 2022

Triazavirin to Be Tested for Effectiveness Against Tick-Borne Encephalitis

Triazavirin was developed by scientists of the Ural Federal University and the Ural Branch of the Russian Academy of Sciences.
Credit: UrFU Press Service

The scientific community has provided research recommendations

The Medsintez plant, the manufacturer of the antiviral drug Triazavirin, plans to conduct studies of the drug for effectiveness against tick-borne encephalitis. Aleksandr Petrov, Chairman of the Board of Directors of the Medsintez Plant LLC, notes that the company has already received recommendations from the scientific community. This was reported by TASS.

"The effectiveness of Triazavirin against tick-borne encephalitis is a very interesting topic to study. Scientists are already saying that the drug can be effective against this virus. Currently we are guided by the opinion of scientists, that is why we are considering the possibility of conducting such studies," said Petrov.

He stressed that this year in some regions there is a high activity of ticks and increased detection of cases of encephalitis, that is why Triazavirin research in this area is relevant.

Medsintez plant is located in Novouralsk (Sverdlovsk region). It specializes in the production of pharmaceutical products. The plant produces infusion solutions, ready forms of genetically engineered human insulin, solid and liquid forms of drugs. The plant manufactures licensed products and is engaged in the creation of new drugs.

Source/Credit: Ural Federal University


Friday, July 29, 2022

COVID vaccine patch fights variants better than needles

A vaccine patch
Credit: University of Queensland

A needle-free vaccine patch could better fight COVID-19 variants, such as Omicron and Delta, than a traditional needle vaccine according to a University of Queensland study in mice.

The research, conducted in partnership with Brisbane biotechnology company Vaxxas, tested the Hexapro SARS-CoV-2 spike vaccine using the Vaxxas high-density microarray patch (HD-MAP) technology, and the results found the patch was far more effective at neutralizing COVID-19 variants.

UQ’s Dr Christopher McMillan said the vaccine patch appeared to counteract new variants more effectively than the current SARs-CoV-2 vaccine delivered by injection.

“The high-density microarray patch is a vaccine delivery platform that precisely delivers the vaccine into the layers of the skin which are rich in immune cells,” Dr McMillan said.

"We found that vaccination via a patch was approximately 11 times more effective at combatting the Omicron variant when compared with the same vaccine administered via a needle."

He said the results extended further than just the Hexapro vaccine.

Thursday, July 28, 2022

New rabies vaccine candidate demonstrates promising immune response and safety

Artist's impression of the rabies virus
Source: University of Oxford

Researchers from the University of Oxford have today reported new findings from a Phase 1 clinical trial studying the immune response and safety of their newly-developed single shot rabies vaccine, ChAdOx2 RabG - with promising results identified.

The RAB001 trial was conducted at the University and is the first time the novel rabies vaccine has been used in human volunteers. The aim of the study was to look at safety and measure immune responses from the vaccine by analyzing levels of rabies neutralizing antibodies – a powerful marker of successful rabies vaccination.

In their findings (published in The Lancet Microbe), the researchers reported that 12 volunteers were recruited into the study in total, with three receiving a low dose, three receiving a medium dose and six receiving a high dose of ChAdOx2 RabG. Strong immune responses against rabies were generated by the vaccine, with all volunteers who received a medium or high dose developing levels of rabies neutralizing antibodies above the World Health Organization protective threshold (0.5 International Units / ml) within two months.

No serious adverse events or safety concerns were reported during the trial. Expected levels of common short-lived vaccine side effects such as soreness at the injection area or feverishness were observed in volunteers, mainly in the medium- and higher-dose groups.

Additionally, the researchers assessed longer term immune responses. Six of the seven middle- and high-dose recipients who returned for an additional follow-up one year after vaccination maintained neutralizing antibody levels above the protective threshold, demonstrating that the immune response from the vaccine persists over time.

Wednesday, July 27, 2022

Scientists use copper nanowires to combat the spread of diseases

Left: Scanning electron microscopy image of the CuNW network on a copper-sprayed surface. Right: Up-close image of CuNW nanowire, which is about 60 nm in diameter, approximately 100x smaller than a human hair.
Resized Image using AI by SFLORG
Credit: Ames National Laboratory

An ancient metal used for its microbial properties is the basis for a materials-based solution to disinfection. A team of scientists from Ames National Laboratory, Iowa State University, and University at Buffalo developed an antimicrobial spray that deposits a layer of copper nanowires onto high-touch surfaces in public spaces. The spray contains copper nanowires (CuNWs) or copper-zinc nanowires (CuZnNWs) and can form an antimicrobial coating on a variety of surfaces. This research was initiated by the COVID-19 pandemic, but the findings have wider-reaching applications.

People have taken advantage of copper’s antimicrobial properties since 2400 B.C. to treat and prevent infections and diseases. It has been proven effective for inactivating viruses, bacteria, fungi, and yeasts when they are directly in contact with the metal. According to Jun Cui, a scientist at Ames Lab and one of the lead researchers on the project, “copper ion can penetrate the membrane of a virus and then insert itself into the RNA chain, and completely disable the virus from duplicating itself.”

Amidst the pandemic, “The DOE asked researchers, what can you do to help to mitigate this COVID situation?” Cui said. Ames Lab is known for work in materials science, not a field that often intersects with disease research. However, Cui’s team came up with the idea to apply copper’s antimicrobial properties to help reduce the spread of COVID.

Cui explained their idea came from a separate project they were working on, which is a copper ink designed for printing copper nanowires used in flexible electronic devices. “So, the thinking is, this is ink, and I can dilute it with water or even ethanol, and then just spray it. Whatever the surface, I spray it once and coat it with a very light layer of copper nanowire,” he said.

NIST Develops Genetic Material for Validating Monkeypox Tests

A vial of the positive control material from NIST that can be used to help ensure the accuracy of tests for monkeypox.   
Credit: R. Press/NIST

In an effort to help speed the expansion of monkeypox testing in the U.S., the National Institute of Standards and Technology (NIST) has produced a material that can help ensure the accuracy of tests for the disease. NIST is making the material, which contains gene fragments from the virus that causes the disease but is noninfectious and safe to handle, freely available for use by test manufacturers and testing laboratories.

Monkeypox is spread by close contact and can cause fever, flu-like symptoms and skin lesions. More than 3,500 cases of monkeypox have been confirmed in the United States since the outbreak began in late May, and the World Health Organization has declared monkeypox to be a global health emergency.

Testing is necessary to identify the extent of an outbreak and contain it, and to properly care for people who have caught the disease and those who may have been exposed. The monkeypox test, like the most sensitive test for COVID-19, uses a technique called polymerase chain reaction, or PCR, to detect genetic sequences from the virus that causes the disease.

Because the material from NIST contains those genetic sequences, laboratories can use it as a positive control — that is, a sample that should cause a positive result if their test is working properly. As the U.S. Centers for Disease Control and Prevention (CDC) works to expand the nation’s testing capacity, the material from NIST will fill a growing need.

What bats can teach us about stopping the next pandemic

Tulane researcher Hannah Frank was part of a team of scientists looking at the complex connections between bats and coronaviruses, and how they evolved together.
Credit: Rusty Costanza

Why are bats often linked to incubating coronaviruses such as those behind COVID-19, SARS and other highly contagious respiratory diseases?

A new Tulane University study suggests that the link between bats and coronaviruses is likely due to a long-shared history, and that their genetic information can help us prevent and manage future pandemics.

Hannah Frank, PhD, a bat expert in the Tulane University School of Science and Engineering, led the effort in collaboration with David Enard (University of Arizona) and Scott Boyd (Stanford University).

“This study gives us greater insight into how mammals, particularly bats, have evolved with coronaviruses. It also highlights broad patterns in susceptibility that may prove useful for managing this and future pandemics.”
Tulane assistant professor Hannah Frank, PhD

“We found that bats have been under unusual pressure from coronaviruses compared to other mammals, supporting the idea that bats are rich sources of coronaviruses and may yield insights for future prevention or treatment,” said Frank, an assistant professor in the Tulane Department of Ecology and Evolutionary Biology.

Scientists develop effective intranasal mumps-based COVID-19 vaccine candidate

Researchers used a modified live attenuated mumps virus, illustrated above, to develop a COVID-19 vaccine candidate.
Credit: Alissa Eckert | CDC

New research has advanced COVID-19 vaccine work in several ways: using a modified live attenuated mumps virus for delivery, showing that a more stable coronavirus spike protein stimulates a stronger immune response, and suggesting a dose up the nose has an advantage over a shot.

Based on these combined findings in rodent experiments, Ohio State University scientists envision one day incorporating a coronavirus antigen into the measles-mumps-rubella (MMR) vaccine as a way to produce COVID-19 immunity in kids.

“We were pushing to make a vaccine for infants and children with the idea that if we could incorporate the mumps COVID vaccine into the MMR vaccine, you’d have protection against four pathogens – measles, mumps, rubella and SARS-CoV-2 – in a single immunization program,” said Jianrong Li, senior author of the study and a professor of virology in Ohio State’s Department of Veterinary Biosciences and Infectious Diseases Institute.

“If infants and children could develop immunity against COVID infection with the MMR vaccine, that would be great – no extra immunization needed.”

The research is published today (July 27, 2022) in Proceedings of the National Academy of Sciences.

To create the antigen that stimulates immunity in this vaccine candidate, researchers used a prefusion version of the SARS-CoV-2 spike protein – the shape it is in on the surface of the virus before the virus infects a cell. The spike was locked into this form by changing six of its amino acids to prolines, an inflexible amino acid.

Viruses help combat antibiotic-resistant bacteria

Prof. Gil Westmeyer (l.) and his research team, in collaboration with Kilian Vogele (r.) and the start-up Invitris, have developed a new controlled production method to create bacteriophages for therapeutic use.
Credit: A. Heddergott / TUM

More and more bacteria are becoming resistant to antibiotics. Bacteriophages are one alternative in the fight against bacteria: These viruses attack very particular bacteria in a highly specific way. Now a Munich research team has developed a new way to produce bacteriophages efficiently and without risk.

The World Health Organization (WHO) regards multi-resistant germs as among the largest threats to health. In the European Union alone, 33,000 people die each year as the result of bacterial infections which cannot be treated with antibiotics. Alternative treatments or drugs are therefore urgently needed.

Bacteriophages, the natural enemies of bacteria, are one promising solution. There are millions of different types of these viruses on earth, each of which specializes in certain bacteria. In nature, the viruses use the bacteria to reproduce; they insert their DNA into the bacteria, where the viruses quickly multiply. Ultimately, they kill off the cell and move on to infect new cells. Bacteriophages work as a specific antibiotic by attacking and destroying a particular type of bacterium.

"Bacteriophages offer an enormous potential for the highly effective, personalized therapy of infectious bacterial diseases," observes Gil Westmeyer, Professor of Neurobiological Engineering at the Technical University of Munich (TUM) and Director of the Institute for Synthetic Biomedicine at Helmholtz Munich. "However, in the past, it wasn't possible to produce bacteriophages in a targeted, reproducible, safe and efficient manner – although these are exactly the decisive criteria for the successful production of pharmaceuticals."

Wednesday, July 6, 2022

How Omicron dodges the immune system

Meriem Bekliz, first author, with a plaque-reduction neutralization assay used to determine the neutralizing capacity of antibodies.
Credit: HUG-UNIGE.

By comparing the neutralization capacity induced by the different variants of SARS-CoV-2, a team from the UNIGE and the HUG reveals the exceptional capacity of Omicron to evade our immunity.

The current wave of COVID-19 highlights a particularly high risk of reinfection by the Omicron variant of SARS-CoV-2. Why is this? A team from the Centre for Emerging Viral Diseases of the University of Geneva (UNIGE) and of the Geneva University Hospital (HUG) analyzed the antibody neutralization capacity of 120 people infected with the original SARS-CoV-2 strain, or with one of its Alpha, Beta, Gamma, Delta, Zeta or Omicron (sub-variant BA.1) variants. And unlike its predecessors, Omicron appears to be able to evade the antibodies generated by all other variants. In vaccinated individuals, while the neutralization capacity is also reduced, it remains far superior to natural immunity alone. This could explain why Omicron is responsible for a net increase in vaccine break-through infections, but not in hospitalizations. These results can be read in the journal Nature Communications.

Tuesday, July 5, 2022

COVID-19 virus spike protein flexibility improved by human cell's own modifications

University of Illinois researchers created atomic-level models of the spike protein that plays a key role in COVID-19 infection and immunity, revealing how the protein bends and moves as it seeks to engage receptors. 
Credit: Tianle Chen

When the coronavirus causing COVID-19 infects human cells, the cell’s protein-processing machinery makes modifications to the spike protein that render it more flexible and mobile, which could increase its ability to infect other cells and to evade antibodies, a new study from the University of Illinois Urbana-Champaign found.

The researchers created an atomic-level computational model of the spike protein and ran multiple simulations to examine the protein’s dynamics and how the cell’s modifications affected those dynamics. This is the first study to present such a detailed picture of the protein that plays a key role in COVID-19 infection and immunity, the researchers said.

Biochemistry professor Emad Tajkhorshid, postdoctoral researcher Karan Kapoor and graduate student Tianle Chen published their findings in the journal PNAS.

“The dynamics of a spike are very important – how much it moves and how flexible it is to search for and bind to receptors on the host cell,” said Tajkhorshid, who also is a member of the Beckman Institute for Advanced Science and Technology. “In order to have a realistic representation, you have to look at the protein at the atomic level. We hope that the results of our simulations can be used for developing new treatments. Instead of using one static structure of the protein to search for drug-binding pockets, we want to reproduce its movements and use all of the relevant shapes it adopts to provide a more complete platform for screening drug candidates instead of just one structure.”

Thursday, June 30, 2022

Some Viruses Make You Smell Tastier to Mosquitoes

Certain smells can attract mosquitoes to human beings, including smells caused by the dengue and Zika viruses. 
Photo credit: by Pixabay

Zika and dengue fever viruses alter the scent of mice and humans they infect, researchers report in the June 30 issue of Journal Cell. The altered scent attracts mosquitoes, which bite the host, drink their infected blood, and then carry the virus to its next victim.

Dengue is spread by mosquitoes in tropical areas around the world, and occasionally in subtropical areas such as the southeastern US. It causes fever, rash, and painful aches, and sometimes hemorrhage and death. More than 50 million dengue cases occur every year, and about 20,000 deaths, most of them in children, according to the National Institutes of Health (NIH) National Institute for Allergy and Infectious Disease.

Zika is another mosquito-spread viral disease in the same family as dengue. Although it is uncommon for Zika to cause serious disease in adults, a recent outbreak in South America caused serious birth defects in the unborn children of infected pregnant women. Yellow fever, Japanese encephalitis, and West Nile are also members of this virus family.

These viruses require ongoing infections in animal hosts as well as mosquitoes in order to spread. If either of these are missing—if all the susceptible hosts clear the virus, or all the mosquitoes die—the virus disappears. For example, during the yellow fever outbreak in Philadelphia in 1793, the coming of the fall frosts killed the local mosquitoes, and the outbreak ended.

Wednesday, June 29, 2022

COVID-19 Fattens Up Our Body’s Cells to Fuel Its Viral Takeover

Illustration of a SARS-CoV-2 viral particle entering a cell. The particle pierces through a cell’s membrane, made of two layers of lipids.  A PNNL-OHSU team has shown how lipids are key to the ability of the virus to replicate.
Credit: Illustration by Michael Perkins | Pacific Northwest National Laboratory

The virus that causes COVID-19 undertakes a massive takeover of the body’s fat-processing system, creating cellular storehouses of fat that empower the virus to hijack the body’s molecular machinery and cause disease.

After scientists discovered the important role of fat for SARS-CoV-2, they used weight-loss drugs and other fat-targeting compounds to try to stop the virus in cell culture. Cut off from its fatty fuel, the virus stopped replicating within 48 hours.

The authors of the recent paper in Nature Communications caution that the results are in cell culture, not in people; much more research remains to see if such compounds hold promise for people diagnosed with COVID. But the scientists, from Oregon Health & Science University and the Department of Energy’s Pacific Northwest National Laboratory, call the work a significant step toward understanding the virus.

“This is exciting work, but it’s the start of a very long journey,” said Fikadu Tafesse, the corresponding author of the study and assistant professor of molecular microbiology and immunology at OHSU. “We have an interesting observation, but we have a lot more to learn about the mechanisms of this disease.”

Monday, June 27, 2022

Virus Discovery Offers Clues About Origins of Complex Life

Comparison of all known virus genomes. Those viruses with similar genomes are grouped together including those that infect bacteria (on the left), eukaryotes (on the right and bottom center). The viruses that infect Asgard archaea are unique from those that have been described before.
Credit: University of Texas at Austin.

The first discovery of viruses infecting a group of microbes that may include the ancestors of all complex life has been found, researchers at The University of Texas at Austin report in Nature Microbiology. The discovery offers tantalizing clues about the origins of complex life and suggests new directions for exploring the hypothesis that viruses were essential to the evolution of humans and other complex life forms.

There is a well-supported hypothesis that all complex life forms such as humans, starfish and trees — which feature cells with a nucleus and are called eukaryotes — originated when archaea and bacteria merged to form a hybrid organism. Recent research suggests the first eukaryotes are direct descendants of the so-called Asgard archaea. The latest research, by Ian Rambo (a former doctoral student at UT Austin) and other members of Brett Baker’s lab, sheds light on how viruses, too, might have played a role in this billions-year-old history.

“This study is opening a door to better resolving the origin of eukaryotes and understanding the role of viruses in the ecology and evolution of Asgard archaea,” Rambo said. “There is a hypothesis that viruses may have contributed to the emergence of complex cellular life.”

Researchers find deadly fungus can multiply by having sex, which could produce more drug-resistant, virulent strains

 Jianping Xu, professor in McMaster University’s
Department of Biology and researcher with Canada’s
Global Nexus for Pandemics and Biological Threats
Credit: McMaster University
Researchers at McMaster University have unlocked an evolutionary mystery of a deadly pathogen responsible for fueling the superbug crisis: it can reproduce by having sex.

And while such fraternizing is infrequent, scientists report it could be producing more drug-resistant and more virulent strains of Candida auris, capable of spreading faster.

C. auris is a fungus that can cause severe infections and sometimes death, often striking immunocompromised hospital patients.

Unlike animals and plants, microorganisms of this nature usually divide and reproduce asexually, so one produces two, two produce four and so on, all genetically identical to each other, through a process of very simple division and without the exchange of genetic material.

“One of the really complex and puzzling questions about this fungal pathogen is its origin and how it reproduces in nature,” says Jianping Xu, a professor in McMaster’s Department of Biology and researcher with Canada’s Global Nexus for Pandemics and Biological Threats.

For the study, recently published online in Computation and Structural Biotechnology Journal, researchers analyzed nearly 1,300 strains available on a public database of C. auris genome sequences. They searched for and confirmed recombination events, or sexual activity.

The findings will help to further research because scientists can now replicate those sexual behaviors in the lab.

“The research tells us that this fungus has been recombined in the past and can recombine in nature, which enables it to generate new genetic variants rather quickly,” explains Xu. “That may sound frightening, but it’s a double-edged sword. Because we learned they could recombine in nature, we could possibly replicate the process in the lab, which could allow us to understand the genetic controls of virulence and drug resistance and potentially other traits that make it such a dangerous pathogen, much faster.”

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