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

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.

Friday, May 12, 2023

Resistant mushroom species spreads

Candida auris infections are difficult to treat and potentially life-threatening. The picture shows yeast cells from C. auris on the left and a fluconazole-resistant C. auris strain on the right.
Image Credit: Alexander Aldejohann

In Germany, too, the number of infections with the Candida auris fungus is increasing. This is shown by a new study by research teams from Würzburg, Jena and Berlin. Despite the low numbers, those involved advise precautionary measures.

Among the yeasts from the genus Candida, that cause infections in humans is the type Candida auris still relatively new: this species was only described in 2009, and no evidence is known before the 1990s. It is unclear which ecological niche C. auris populated and why human infections have increased since the turn of the millennium.

The treatment of C. auris infections are made considerably more difficult by the potential of the pathogen to develop resistance to all available antifungals classes. In addition, C. auris unlike others Candida- Types, are efficiently transmitted from patient to patient via direct and indirect contact, thus leading to hospital outbreaks that are difficult to control.

Thursday, May 11, 2023

Brain-Belly Connection: Gut Health May Influence Likelihood of Developing Alzheimer’s

UNLV study pinpoints 10 bacterial groups associated with Alzheimer’s disease, provides new insights into the relationship between gut makeup and dementia.
Illustration Credit: Julien Tromeur

Could changing your diet play a role in slowing or even preventing the development of dementia? We’re one step closer to finding out, thanks to a new UNLV study that bolsters the long-suspected link between gut health and Alzheimer’s disease.

The analysis — led by a team of researchers with the Nevada Institute of Personalized Medicine (NIPM) at UNLV and published this spring in the Nature journal Scientific Reports — examined data from dozens of past studies into the belly-brain connection. The results? There’s a strong link between particular kinds of gut bacteria and Alzheimer’s disease.

Between 500 and 1,000 species of bacteria exist in the human gut at any one time, and the amount and diversity of these microorganisms can be influenced by genetics and diet.

The UNLV team’s analysis found a significant correlation between 10 specific types of gut bacteria and the likelihood of developing Alzheimer’s disease. Six categories of bacteria — Adlercreutzia, Eubacterium nodatum group, Eisenbergiella, Eubacterium fissicatena group, Gordonibacter, and Prevotella9 — were identified as protective, and four types of bacteria — Collinsella, Bacteroides, Lachnospira, and Veillonella — were identified as a risk factor for Alzheimer’s disease.

Like ancient mariners, ancestors of Prochlorococcus microbes rode out to sea on exoskeleton particles

New research suggests the Prochlorococcus microbe’s ancient coastal ancestors colonized the ocean by rafting out on chitin particles.
Illustration Credit: Jose-Luis Olivares/MIT
(CC BY-NC-ND 3.0)

Throughout the ocean, billions upon billions of plant-like microbes make up an invisible floating forest. As they drift, the tiny organisms use sunlight to suck up carbon dioxide from the atmosphere. Collectively, these photosynthesizing plankton, or phytoplankton, absorb almost as much CO2 as the world’s terrestrial forests. A measurable fraction of their carbon-capturing muscle comes from Prochlorococcus — an emerald-tinged free-floater that is the most abundant phytoplankton in the oceans today.

But Prochlorococcus didn’t always inhabit open waters. Ancestors of the microbe likely stuck closer to the coasts, where nutrients were plentiful and organisms survived in communal microbial mats on the seafloor. How then did descendants of these coastal dwellers end up as the photosynthesizing powerhouses of the open oceans today?

MIT scientists believe that rafting was the key. In a new study they propose that ancestors of Prochlorococcus acquired an ability to latch onto chitin — the degraded particles of ancient exoskeletons. The microbes hitched a ride on passing flakes, using the particles as rafts to venture further out to sea. These chitin rafts may have also provided essential nutrients, fueling and sustaining the microbes along their journey.

Ancestral mitoviruses discovered in mycorrhizal fungi

Arbuscular mycorrhizal (AM) fungi in the Glomeromycotina colonize plant roots (left, micrograph) and deliver water and nutrients from soil (right).
Image Credit: Tatsuhiro Ezawa

A new group of mitochondrial viruses confined to the arbuscular mycorrhizal fungi Glomeromycotina may represent an ancestral lineage of mitoviruses.

Mitochondria are organelles in the cells of almost all eukaryotes — organisms with cells that have a nucleus. They were originally free-living bacteria capable of generating energy in the presence of oxygen; then engulfed by an ancestral eukaryotic cell where they became mitochondria, the site of cellular respiration and many important metabolic processes. In humans, dysfunctions of mitochondria are associated with aging and many diseases.

Bacteriophages are viruses that infect bacteria. As former bacteria, there are also viruses that infect mitochondria, known as mitoviruses, which evolved from bacteriophages. While mitoviruses have been found in fungi, plants, and invertebrates, they are not well studied.

Associate Professor Tatsuhiro Ezawa at Hokkaido University, Professor Luisa Lanfranco at University of Torino, and Dr. Massimo Turina at National Research Council of Italy (CNR) Torino led an international team to discover a new group of mitoviruses, called large duamitoviruses. Their findings were published in the journal mBio.

Tuesday, May 2, 2023

Essential mechanism for bacterial gut colonization discovered

Tomogram of a Bacteroides thetaiotaomicron cell.
Image Credit: Matthew Swulius / Pennsylvania State University
(CC BY-NC-ND 4.0)

New light has been shed on a key event that contributes to the successful colonization of bacteria in the gut of mice, according to a new study from Yale University and Penn State. The study, published in Science, reveals that a physical process called "liquid-liquid phase separation" is essential for the survival and colonization of the beneficial bacteria Bacteroides thetaiotaomicron in the gut.

“In our field we are trying to understand how bacteria can colonize your gut and what the molecular components are that allow these organisms to reside in your intestines, because not all bacteria can,” said Guy Townsend, assistant professor of biochemistry and molecular biology at the Penn State College of Medicine and an author on the paper. Prior to this work, researchers did not understand the mechanisms that allowed B. thetaiotaomicron to thrive in the gut of mammals.

The researchers demonstrated the crucial role played by an “intrinsically disordered domain” (IDR) within a particular protein in the bacterium, called Rho, that facilitates liquid-liquid phase separation.

Liquid-liquid phase separation is when two liquids that don't mix well separate into different parts because of their chemical differences. This process helps cells create structures that don't have a membrane and are important for many cell functions.

Wednesday, April 26, 2023

Near-universal T cell immunity towards a broad range of bacteria

Neutralizing the bacterially derived cytotoxic bomb: the pneumococci lie in the background, an array of macrophages and dendritic cells are arranged around the central image of a T cell. Rows of TCRs interacting with the identified pneumolysin epitope bound to HLA (white) cross the length and breadth of the artwork, emphasizing their centrality in the immune response.
Illustration Credit: Dr. Erica Tandori.

Typically, T cells of the immune system respond to a specific feature (antigen) of a microbe, thereby generating protective immunity. As reported in the journal Immunity, an international team of scientists have discovered an exception to this rule. Namely, a group of divergent bacterial pathogens, including pneumococci, all share a small highly conserved protein sequence, which is both presented and recognized by human T cells in a conserved population-wide manner.

The study set out to understand immune mechanisms that protect against pneumococcus, a bacterial pathobiont that can reside harmlessly in the upper respiratory mucosae but can also cause infectious disease, especially in infants and older adults, which can range from middle ear and sinus infections to pneumococcal pneumonia and invasive bloodstream infections.

Most currently used pneumococcal polysaccharide-based conjugate vaccines (PCVs) are effective against 10–13 serotypes, but growing serotype replacement becomes a problem.

Tuesday, April 25, 2023

Hunting for microbes in the global ocean

Hunting for microbes in the global ocean. Sampling of seawater is performed with Niskin Bottles, which are cylindrical container used in oceanography to collect water samples containing microbes at various depths, triggered to snap shut at the desired depth.
Photo Credit: © 2022 Federico Baltar

A team of international researchers led by Federico Baltar of the University of Vienna and José M González of the University of La Laguna has identified a previously unknown group of bacteria, called UBA868, as key players in the energy cycle of the deep ocean. They are significantly involved in the biogeochemical cycle in the marine layer between 200 and 1000 meters. The results have now been published in the journal Nature Microbiology.

The deep sea, the marine layer at depths of 200 meters and more, accounts for about 90 percent of the world's ocean volume. It forms the largest habitat on Earth and is home to the largest number of microorganisms. These microorganisms contribute significantly to the biogeochemical cycles. They extract organic material, for example from phytoplankton and zooplankton, transform it and make it available again to the ecosystem as nutrients. In this way, they play a major role in the fixation and cycling of carbon. Dissolved sulfur compounds are also converted by bacteria and returned to the material cycle. 

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