. Scientific Frontline: Microbiology
Showing posts with label Microbiology. Show all posts
Showing posts with label Microbiology. Show all posts

Tuesday, October 3, 2023

Gut bacteria found in wild wolves may be key to improving domestic dogs’ health

Photo Credit: Nicky Pe

Gut microbes found in wild wolves may be the key to alleviating a debilitating gastrointestinal condition common to domestic dogs, according to a study led by researchers at Oregon State University – Cascades.

In a paper published in Applied Microbiology, the authors report a novel strain of Paenibacillus bacteria with characteristics of a probiotic – an organism that conveys a health benefit to the host.

In this case, the benefit would be to head off canine inflammatory bowel disease, a chronic illness characterized by vomiting, reduced appetite, weight loss, flatulence, a rumbling stomach and/or abdominal discomfort, said Bruce Seal of OSU-Cascades’ biology program.

“At present there is no known cure for this ongoing dysbiosis of the gastrointestinal tract, and there are limited options for treatment,” Seal said. “Underlying causes of the condition include an animal’s genetics, environmental factors, the immunological state of the GI tract and, maybe most importantly, an altered gut microbiome.”

Monday, October 2, 2023

Discrimination alters brain-gut ‘crosstalk,’ prompting poor food choices and increased health risks

Illustration Credit: julientromeur

People frequently exposed to racial or ethnic discrimination may be more susceptible to obesity and related health risks in part because of a stress response that changes biological processes and how we process food cues. These are findings from UCLA researchers conducting what is believed to be the first study directly examining effects of discrimination on responses to different types of food as influenced by the brain-gut-microbiome (BGM) system.

The changes appear to increase activation in regions of the brain associated with reward and self-indulgence – like seeking “feel-good” sensations from “comfort foods” – while decreasing activity in areas involved in decision making and self-control.

“We examined complex relationships between self-reported discrimination exposure and poor food choices, and we can see these processes lead to increased cravings for unhealthy foods, especially sweet foods, but also manifested as alterations in the bidirectional communication between the brain and the gut microbiome,” said Arpana Gupta, PhD, a researcher and co-director of the UCLA Goodman-Luskin Microbiome Center and the UCLA G. Oppenheimer Center for Neurobiology of Stress and Resilience.

Heavily mutated SARS-CoV-2 variant BA.2.86 not as resistant to antibodies as first feared

Image Credit: Fusion Medical Animation

Researchers at Karolinska Institutet who studied SARS-CoV-2 variant BA.2.86, found that the new variant was not significantly more resistant to antibodies than several other variants that are circulating. The study also showed that antibody levels to BA.2.86 were significantly higher after a wave of XBB infections compared to before, suggesting that the vaccines based on XBB should provide some cross-protection to BA.2.86.

"We engineered a spike gene that matches that of the BA.2.86 variant and tested the blood of Stockholm blood donors (specifically those donations made very recently) to see how effective their antibodies are against this new variant. We found that although BA.2.86 was quite resistant to neutralizing antibodies, it wasn't significantly more resistant than a number of other variants that are also circulating", says Daniel Sheward, lead author of the study and Postdoctoral researcher in Benjamin Murrell's team at the Department of Microbiology, Tumor and Cell Biology at Karolinska Institutet.

Friday, September 29, 2023

A lethal parasite’s secret weapon: infecting non-immune cells

Photomicrograph of spleen tissue showing the presence of numerous Leishmania donovani parasites in the amastigote form they take after infecting a host.
Image Credit: Centers for Disease Control and Prevention

The organisms that cause visceral leishmaniasis, a potentially deadly version of the parasitic disease that most often affects the skin to cause disfiguring disease, appear to have a secret weapon, new research suggests: They can infect non-immune cells and persist in those uncommon environments. 

Researchers found the Leishmania donovani parasites in blood-related stem cells in the bone marrow of chronically infected mice – precursor cells that can regenerate all types of cells in the blood-forming system. The finding may help explain why some people who develop visceral leishmaniasis, which is fatal if left untreated, often also have blood disorders such as anemia. 

Identifying these cells and other unexpected locations in which these parasites live improve scientists’ understanding of the disease and may lead to new treatment options, said senior study author Abhay Satoskar, professor of pathology in The Ohio State University College of Medicine. 

Soil bacteria prevail despite drought conditions

ClimGrass, the field experiment in Styria, in which drought is simulated in combination with future climate conditions.
Photo Credit: Markus Herndl, HBLFA Raumberg-Gumpenstein

Recent research uncovers the resilience of certain soil microorganisms in the face of increasing drought conditions. While many bacteria become inactive during dry spells, specific groups persist and even thrive. This study, conducted by the Centre for Microbiology and Environmental Systems Science (CeMESS) at the University of Vienna, offers ground-breaking insights into bacterial activity during drought periods, with implications for agriculture and our understanding of climate change impacts. The study has been published in the renowned scientific journal Nature Communications.

The images of the parched Po Valley in 2022 and this year's forest fires in Greece underscore the reality of extreme droughts – not just as news headlines but as immediate threats. The repercussions for humans and plant life are evident: crop failures, withered meadows, and water rationing. However, the impact of drought on soil microorganisms remains hidden from the naked eye.

Soil microorganisms play a pivotal role in ecosystems. They contribute to soil fertility, assist plants in nutrient absorption, and determine whether soils store or release CO2, thereby influencing climate change trajectories. Until now, measuring the activity of microorganisms in dry soils and identifying which species remain active was challenging. Thanks to a novel method developed by scientists at the University of Vienna, bacterial activity during drought periods can now be observed.

Wednesday, September 27, 2023

Understanding bacterial motors may lead to more efficient nanomachine motors

The FliG protein in the "bacterial motor"
Illustration Credit: Atsushi Hijikata, Yohei Miyanoiri, Osaka University

A research group led by Professor Emeritus Michio Homma (he, him) and Professor Seiji Kojima (he, him) of the Graduate School of Science at Nagoya University, in collaboration with Osaka University and Nagahama Institute of Bio-Science and Technology, have made new insights into how locomotion occurs in bacteria. The group identified the FliG molecule in the flagellar layer, the ‘motor’ of bacteria, and revealed its role in the organism. These findings suggest ways in which future engineers could build nanomachines with full control over their movements. They published the study in iScience

As nanomachines become smaller, researchers are taking inspiration from microscopic organisms for ways to make them move and operate. In particular, the flagellar motor can rotate clockwise and counterclockwise at a speed of 20,000 rpm. If scaled up, it would be comparable to a Formula One engine with an energy conversion efficiency of almost 100% and the capacity to change its rotation direction instantly at high speeds. Should engineers be able to develop a device like a flagellar motor, it would radically increase the maneuverability and efficiency of nanomachines. 

Double Trouble: Infamous “Eagle Killer” Bacterium Produces Not One, But Two Toxins

Colony of A. hydrillicola
Photo Credit: Lenka Štenclová

The cyanobacterium Aetokthonos hydrillicola produces not just one, but two highly potent toxins. In the latest issue of the journal Proceedings of the National Academy of Sciences (PNAS), an international team led by Martin Luther University Halle-Wittenberg (MLU) and Freie Universität Berlin describes the second toxin, which had remained elusive until now. Even in low concentrations, it can destroy cells and is similar to substances currently used in cancer treatment. Two years ago, the same team established that the first toxin from the cyanobacterium is the cause of a mysterious disease among bald eagles in the USA.

Aetokthonos hydrillicola is particularly challenging for researchers. It is notoriously difficult to cultivate and produces one of its toxins only under specific conditions. The fact that it produces two toxins with very different chemical makeups is also unusual. Cyanobacteria normally produce only one toxin - and A. hydrillicola was established as the source of aetokthonotoxin in 2021. This discovery was made by Professor Susan Wilde from the University of Georgia (USA) and Professor Timo Niedermeyer, who worked at MLU until July 2023 and has now joined the researchers at Freie Universität Berlin. This toxin solved a riddle that had kept scientists busy for decades: it triggers the disease vacuolar myelinopathy (VM) among bald eagles in the United States. VM causes holes to form in the brain and, as a result, the birds lose control of their bodies. Science ran the breakthrough as a cover story at the time, and the international team picked up several awards for its work.

Monday, June 19, 2023

“Predatory bacteria” provide hope for chlorine-free drinking water

The inside of a water pipe
Photo Credit: Krisjtan Pullerits / Lund University

In a unique study carried out in drinking water pipes in Sweden, researchers from Lund University and the local water company tested what would happen if chlorine was omitted from drinking water. The result? An increase in bacteria, of course, but after a while something surprising happened: a harmless predatory bacteria grew in numbers and ate most of the other bacteria. The study suggests that chlorine is not always needed if the filtration is efficient - and that predatory bacteria could perhaps be used to purify water in the future.

Just as human intestines contain a rich bacterial flora, many types of bacteria thrive in our drinking water and the pipes that transport them. On the inside of pipe walls is a thin, slippery coating, called a biofilm, which protects and supports bacteria. These bacteria have adapted to life in the presence of chlorine, which otherwise has the primary task to kill bacteria, particularity bacteria that can make humans sick.  

An ordinary glass of drinking water contains a lot of harmless bacteria. Chlorine, however, which in the studied piping system was added in the form of monochloramine, is not wholly unproblematic.

Simple maintenance can reduce hospital Legionella risks

Photo Credit: PublicDomainPictures

Hospital water systems are a significant source of Legionella, resulting in the potentially fatal Legionnaires’ disease – but Flinders University researchers have proven simple maintenance that involves running hot water regularly and flushing the pipes has a huge effect in reducing the risk of the disease.

One of the biggest challenges for Legionella management within large hospital systems is that under unfavorable conditions, Legionella transforms itself into a state (called viable but non culturable – VBNC) that cannot be detected using standard methods.

To understand the extent of the problem, Flinders University researchers conducted the first comprehensive study that quantified all Legionella, including those in the VBNC state, and free-living amoebae from a hospital water system under dynamic flow and temperature conditions.

“We took a different approach because we didn’t know how often the standard method was returning false negative results for Legionella and it’s really hard to determine the optimal management approach if you can’t trust your testing method,” says Flinders University’s Associate Professor Harriet Whiley.

Saturday, June 17, 2023

New insights on bacteria that causes food poisoning

The pathogenic genes of Providencia rustigianii can be transferred to Enterobacteriaceae as well.
   Illustration Credit: Shinji Yamasaki, Osaka Metropolitan University

Latest research reveals the properties of a type of food poisoning bacteria, and paves way for establishment of preventive methods.

The transfer of pathogenic genes between not only same bacterial species but also different species

Recently, Providencia spp. which have been detected in patients with gastroenteritis, and similar to enterohemorrhagic Escherichia coli. O157 and Salmonella spp., have been attracting attention as causative agents of food poisoning. For children with low immunity, food poisoning can be lethal as it causes severe symptoms such as diarrhea and dehydration, so clarifying the source of infection and pathogenic factors of Providencia spp., and establishing preventive methods are urgent issues worldwide.

Thursday, June 15, 2023

Altered gut bacteria may be early sign of Alzheimer’s disease


Alzheimer’s disease causes changes to the brain that begin two decades or more before symptoms appear. A study by researchers at Washington University School of Medicine in St. Louis reveals that the bacteria that live in the gut also change before Alzheimer’s symptoms arise, a discovery that could lead to diagnostics or treatments for Alzheimer’s disease that target the gut microbiome.
Image Credit: Gerd Altmann

People in the earliest stage of Alzheimer’s disease — after brain changes have begun but before cognitive symptoms become apparent — harbor an assortment of bacteria in their intestines that differs from the gut bacteria of healthy people, according to a study by researchers at Washington University School of Medicine in St. Louis.

The findings, published June 14 in Science Translational Medicine, open up the possibility of analyzing the gut bacterial community to identify people at higher risk of developing dementia, and of designing microbiome-altering preventive treatments to stave off cognitive decline.

“We don’t yet know whether the gut is influencing the brain or the brain is influencing the gut, but this association is valuable to know in either case,” said co-corresponding author Gautam Dantas, PhD, the Conan Professor of Laboratory and Genomic Medicine. “It could be that the changes in the gut microbiome are just a readout of pathological changes in the brain. The other alternative is that the gut microbiome is contributing to Alzheimer’s disease, in which case altering the gut microbiome with probiotics or fecal transfers might help change the course of the disease.”

Elimination of type of bacteria suggests treatment for endometriosis

Fusobacterium (white dots) is highly expressed near the uterus (endometrium) of endometriosis patients.
Image Credit: Professor Yutaka Kondo

A research group from the Graduate School of Medicine and iGCORE at Nagoya University in Japan, has discovered that using an antibiotic to target Fusobacterium reduced the formation of lesions associated with endometriosis, a gynecological disorder characterized by endometrial tissue usually found inside the uterus being found outside it. Their findings suggest an alternative treatment for this disorder. The study was published in Science Translational Medicine.

Endometriosis affects one in ten women between the ages of 15 and 49. The disorder can cause lifelong health problems, including pelvic pain and infertility. Although it can be treated using hormone therapy and surgical resection, these procedures sometimes lead to side effects, recurrence, and a significant impact on pregnancy.

The group led by Professor Kondo (he, him) and Assistant Professor Ayako Muraoka (she, her) from the Nagoya University Graduate School of Medicine, in collaboration with the National Cancer Center, found that the uterus of mice infected with Fusobacterium had more and heavier lesions. However, mice that had been given an antibiotic to eradicate Fusobacterium saw improved lesion formation.

Wednesday, June 14, 2023

A marine mystery: finding the link between climate change and sea sponge loss

The latest findings suggest that thermal stress disturbs sponge-microbes symbiosis, which likely causes the sponge to die.
Photo Credit: Heidi Luter.

Microbes could hold the key to explaining how climate change affects sea sponges, warn scientists from UNSW Sydney. 

Sea sponges are essential to marine ecosystems. They play critical roles in the ocean, as they provide shelter and food to a plethora of marine creatures, recycle nutrients by filtering thousands of liters of sea water daily, and are hosts to microbes that may be the key to some of the most pressing medical challenges we face today. 

Now, scientists from UNSW have discovered that when a tropical sea sponge is exposed to warmer temperatures, it loses an important microbe, which could explain why the sponge tissue dies.  

The latest study, published in ISME Communications, has revealed that by exposing sea sponges to a temperature increase of 3°C, one essential microbe abandons the sponge, potentially causing tissue poisoning.   

The collaboration between researchers from UNSW, Heidi Luter from the Australian Institute of Marine Science and James Bell from the Victoria University of Wellington, has added an important piece to the puzzle on the impact of climate change on sponge populations around the world. 

Tuesday, June 13, 2023

Vaccine against deadly chytrid fungus primes frog microbiome for future exposure

A new study led by researchers at Penn State found that a new vaccine against the deadly chytrid fungus in frogs can shift the composition of the microbiome, making frogs more resilient to future exposure to the fungus.
Photo Credit: Paul Bonnar

A human's or animal’s microbiome — the collection of often beneficial microorganisms, including bacteria and fungi, that live on or within a host organism — can play an important role in the host’s overall immune response, but it is unclear how vaccines against harmful pathogens impact the microbiome. A new study led by researchers at Penn State found that a new vaccine against the deadly chytrid fungus in frogs can shift the composition of the microbiome, making frogs more resilient to future exposure to the fungus. The study, published June 12 in a special issue of the journal Philosophical Transactions of the Royal Society B, suggests that the microbiome response could be an important, overlooked part of vaccine efficacy.

“The microorganisms that make up an animal’s microbiome can often help defend against pathogens, for example by producing beneficial metabolites or by competing against the pathogens for space or nutrients,” said Gui Becker, associate professor of biology at Penn State and leader of the research team. “But what happens to your microbiome when you get a vaccine, like a COVID vaccine, flu shot, or a live-attenuated vaccine like the yellow fever vaccine? In this study, we used frogs as a model system to start exploring this question.”

Frogs and other amphibians are threatened by the chytrid fungus, which has led to extinctions of some species and severe population declines in hundreds of others across several continents. In susceptible species, the fungus causes a sometimes-lethal skin disease.

Monday, June 12, 2023

Cholera bacteria form aggressive biofilm to kill immune cells

The cholera-pathogen Vibrio cholerae (blue) forms an aggressive biofilm on the surface of immune cells (red).
Video Credit: University of Basel, Biozentrum

Bacteria harness the power of communities. A research group at the University of Basel has now discovered that the bacterial pathogen that causes cholera forms a novel type of bacterial community on immune cells: an aggressive biofilm that is lethal for the cells. The study, recently published in the journal Cell, provides new insights into the infection strategies of pathogens.

Many bacteria adopt a fascinating defense strategy by forming communities on surfaces, known as biofilms. We encounter such biofilms in our daily lives, for example, as dental plaque in the mouth, slimy films on stones in water or even as part of our intestinal flora. Bacterial biofilms are intrinsically tolerant to antibiotics and can pose a significant threat in clinical settings when they colonize implants, catheters, or surgical instruments. This colonization enables pathogens to infiltrate our body and trigger infections that are difficult to combat by the immune system and with antibiotics.

Previously, it was assumed that bacteria form biofilms to defend and protect themselves. The research team led by Professor Knut Drescher at the Biozentrum, University of Basel, has now demonstrated, in their recently published “Cell” study, that bacteria form biofilms on the surface of immune cells. This previously unknown type of community differs from already known bacterial biofilms not only in its structure, but also in its function: instead of serving a protective purpose, this biofilm is an aggressive trait.

Sunday, June 11, 2023

Modified lactic acid bacteria provide faster wound healing

The lactic acid bacteria, or Limosilactobacillus reuteri, is genetically modified to produce the chemokine CXCL12 (ILP100-Topical). 
Photo Credit: Martina Sjaunja

Complicated, hard-to-heal wounds are a growing medical problem and there are currently only two drugs approved with proven efficacy. In a new study on humans, researchers at Uppsala University show that treatment with a specific type of modified lactic acid bacteria works well and has a positive effect on the healing of wounds.

In several controlled preclinical models, the research team behind the new study has previously demonstrated accelerated wound healing after topical treatment (treatment on the skin) using lactic acid bacteria, or Limosilactobacillus reuteri, genetically modified to produce the chemokine CXCL12 (ILP100-Topical).

The researchers can now show data from the first clinical study on humans, in which the main objective was to establish safety and tolerability. Other objectives were to see clinical and biological effects on wound healing using traditionally accepted methods, as well as more exploratory and traceable measurements.

36 healthy volunteers were included in the study with a total of 240 induced wounds studied. The study’s design and methodology are described in more detail below.

Friday, June 9, 2023

Bacteria with a taste for inflammation could help protect against heart disease

Nacho Vivas, lab manager at the Rey Lab in the Bacteriology Department at the University of Wisconsin–Madison, checks on a group of germ-free mice inside a sterile lab environment on June 22, 2015. Research led by Federico Rey has found some microbes in the guts of humans and mice may help control the buildup of plaque in arteries, the leading cause of cardiovascular disease, by gobbling up a group of inflammatory chemicals before they can circulate in the body.
Photo Credit: Bryce Richter

Some microbes in the guts of humans and mice may help control the buildup of plaque in arteries, the leading cause of cardiovascular disease, by gobbling up a group of inflammatory chemicals before they can circulate in the body.

New research from the University of Wisconsin–Madison and collaborators around the world identified bacteria able to break down uric acid in the low-oxygen environment of the intestines and the specific genes that enable the process. They describe a new way in which gut microbes may influence our health and a potential avenue to treat gout or prevent heart disease.

Uric acid is a product of the breakdown in the human body of purines, a class of molecules that include those necessary for life, like adenine and guanine (two of the basic building blocks of DNA), and some that are life indulgences, like caffeine and theobromine (found in chocolate and tea leaves). Most uric acid is cleaned out by healthy kidneys, but about 30 percent of it spills into the gut. Too much uric acid leads to a painful condition called gout.

Thursday, June 8, 2023

Some Gut Bacteria Linked to Precancerous Colon Polyps

Scientific Frontline stock graphic

A new study by Harvard Medical School investigators at Massachusetts General Hospital has linked certain types of gut bacteria to the development of precancerous colon polyps. Their results are published in Cell Host & Microbe.

“Researchers have done a lot of work to understand the relationship between the gut microbiome and cancer. But this new study is about understanding the microbiome’s influence on precancerous polyps,” said co-corresponding author Daniel C. Chung, HMS professor of medicine, medical co-director of the Center for Cancer Risk Assessment at Mass General Cancer Center, and a faculty member of the gastroenterology division at Mass General.

“Through the microbiome, we potentially have an opportunity to intervene and prevent colorectal cancer from forming,” he said.

Colorectal cancer is the second-leading cause of cancer-related deaths in the U.S., and rates of colorectal cancer are rising among young adults.

Nearly all colorectal cancers arise from a precancerous polyp. One of the best ways to reduce the incidence of colorectal cancer is to stop the growth at the polyp stage.

Monday, June 5, 2023

How Studying Poop May Help Us Boost White Rhino Populations

White Rhinoceros with baby, being protected from poachers. Shot in the Kruger National Park, South Africa.
Photo Credit: Nadine Venter

Researchers at North Carolina State University have identified significant differences in the gut microbiome of female southern white rhinos who are reproducing successfully in captivity, as compared to females who have not reproduced successfully in captivity. The work raises questions about the role that a particular genus of gut microbes may be playing in limiting captive breeding of this rhinoceros species.

“Our work focuses on the southern white rhinoceros (Ceratotherium simum simum), because while it is not yet endangered, species numbers are declining in the wild due to poaching,” says Christina Burnham, first author of a paper on the work and a former graduate student at NC State.

“There is a significant population of southern white rhinos under human care in the United States, but there have been challenges in getting many of these animals to reproduce successfully. It is critical we understand why, as the managed rhinos serve as important assurance populations in case wild rhino numbers continue to fall. We wanted to know how the gut microbiome may influence the reproductive ability of these rhinos.”

Monday, May 15, 2023

Phage structure captured for the first time, to benefit biotech applications

Phage image
Image Credit: Dr Vicki Gold et al, Nature Communications

New insights into the structure of phages will enable researchers to develop new uses for viruses in biotechnology.

Phages are viruses that infect bacteria, which enables them to be exploited as tools in biotechnology and medicine. Now, for the first time, researchers at the University of Exeter, in collaboration with Massey University and Nanophage Technologies, New Zealand, have mapped out what a commonly-used form of phage looks like, which will help researchers design better uses in future.

One common use for phage is phage display, which is a useful tool in drug discovery. Phage display works by linking a gene fragment of interest to a phage gene that makes one of the phage coat proteins. The new coat protein with the linked protein of interest appears on the surface of the phage, where it can be assayed and tested for biological activity.

Billions of types of phages exist. Phage display often uses a type of phage known as filamentous, so called because they are long and thin, making the display of many proteins across its surface possible. Although phage display and other applications have proved successful, until now, scientists have not known what this type of phage looks like.

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