A protein with a molecular weight of 40,000 isolated from bacterial flagella. At appropriate pH and salt concentration, three flagellin monomers can spontaneously reaggregate to form structures which appear identical to intact flagella.
A pattern recognition receptor that binds FLAGELLIN. It mediates cellular responses to certain bacterial pathogens.
A whiplike motility appendage present on the surface cells. Prokaryote flagella are composed of a protein called FLAGELLIN. Bacteria can have a single flagellum, a tuft at one pole, or multiple flagella covering the entire surface. In eukaryotes, flagella are threadlike protoplasmic extensions used to propel flagellates and sperm. Flagella have the same basic structure as CILIA but are longer in proportion to the cell bearing them and present in much smaller numbers. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
Proteins found in any species of bacterium.
A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.
A genus of gram-negative, facultatively anaerobic, rod-shaped bacteria that utilizes citrate as a sole carbon source. It is pathogenic for humans, causing enteric fevers, gastroenteritis, and bacteremia. Food poisoning is the most common clinical manifestation. Organisms within this genus are separated on the basis of antigenic characteristics, sugar fermentation patterns, and bacteriophage susceptibility.
A species of bacteria that resemble small tightly coiled spirals. Its organisms are known to cause abortion in sheep and fever and enteritis in man and may be associated with enteric diseases of calves, lambs, and other animals.
The functional hereditary units of BACTERIA.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
An inhibitor of apoptosis protein that was initially identified during analysis of CHROMOSOME DELETIONS associated with SPINAL MUSCULAR ATROPHY. Naip contains a nucleotide binding oligomerization domain and a carboxy-terminal LEUCINE rich repeat.
A family of pattern recognition receptors characterized by an extracellular leucine-rich domain and a cytoplasmic domain that share homology with the INTERLEUKIN 1 RECEPTOR and the DROSOPHILA toll protein. Following pathogen recognition, toll-like receptors recruit and activate a variety of SIGNAL TRANSDUCING ADAPTOR PROTEINS.
Gram-negative helical bacteria, in the genus BORRELIA, that are the etiologic agents of LYME DISEASE. The group comprises many specific species including Borrelia afzelii, Borellia garinii, and BORRELIA BURGDORFERI proper. These spirochetes are generally transmitted by several species of ixodid ticks.
A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A member of the CXC chemokine family that plays a role in the regulation of the acute inflammatory response. It is secreted by variety of cell types and induces CHEMOTAXIS of NEUTROPHILS and other inflammatory cells.
The capacity of a normal organism to remain unaffected by microorganisms and their toxins. It results from the presence of naturally occurring ANTI-INFECTIVE AGENTS, constitutional factors such as BODY TEMPERATURE and immediate acting immune cells such as NATURAL KILLER CELLS.
Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.
Substances elaborated by bacteria that have antigenic activity.
Vaccines or candidate vaccines used to prevent or treat PSEUDOMONAS INFECTIONS.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.

Comparison of flagellin genes from clinical and environmental Pseudomonas aeruginosa isolates. (1/1391)

Pseudomonas aeruginosa, an important opportunistic pathogen, was isolated from environmental samples and compared to clinically derived strains. While P. aeruginosa was isolated readily from an experimental mushroom-growing unit, it was found only rarely in other environmental samples. A flagellin gene PCR-restriction fragment length polymorphism analysis of the isolates revealed that environmental and clinical P. aeruginosa strains are not readily distinguishable. The variation in the central regions of the flagellin genes of seven of the isolates was investigated further. The strains used included two strains with type a genes (998 bp), four strains with type b genes (1,258 bp), and one strain, K979, with a novel flagellin gene (2,199 bp). The route by which flagellin gene variation has occurred in P. aeruginosa is discussed.  (+info)

Transcription initiation at the flagellin promoter by RNA polymerase carrying sigma28 from Salmonella typhimurium. (2/1391)

The sigma subunit of RNA polymerase is a critical factor in positive control of transcription initiation. Primary sigma factors are essential proteins required for vegetative growth, whereas alternative sigma factors mediate transcription in response to various stimuli. Late gene expression during flagellum biosynthesis in Salmonella typhimurium is dependent upon an alternative sigma factor, sigma28, the product of the fliA gene. We have characterized the intermediate complexes formed by sigma28 holoenzyme on the pathway to open complex formation. Interactions with the promoter for the flagellin gene fliC were analyzed using DNase I and KMnO4 footprinting over a range of temperatures. We propose a model in which closed complexes are established in the upstream region of the promoter, including the -35 element, but with little significant contact in the -10 element or downstream regions of the promoter. An isomerization event extends the DNA contacts into the -10 element and the start site, with loss of the most distal upstream contacts accompanied by DNA melting to form open complexes. Melting occurs efficiently even at 16 degrees C. Once open complexes have formed, they are unstable to heparin challenge even in the presence of nucleoside triphosphates, which have been observed to stabilize open complexes at rRNA promoters.  (+info)

The Yersinia enterocolitica motility master regulatory operon, flhDC, is required for flagellin production, swimming motility, and swarming motility. (3/1391)

The ability to move over and colonize surface substrata has been linked to the formation of biofilms and to the virulence of some bacterial pathogens. Results from this study show that the gastrointestinal pathogen Yersinia enterocolitica can migrate over and colonize surfaces by swarming motility, a form of cooperative multicellular behavior. Immunoblot analysis and electron microscopy indicated that swarming motility is dependent on the same flagellum organelle that is required for swimming motility, which occurs in fluid environments. Furthermore, motility genes such as flgEF, flgMN, flhBA, and fliA, known to be required for the production of flagella, are essential for swarming motility. To begin to investigate how environmental signals are processed and integrated by Y. enterocolitica to stimulate the production of flagella and regulate these two forms of cell migration, the motility master regulatory operon, flhDC, was cloned. Mutations within flhDC completely abolished swimming motility, swarming motility, and flagellin production. DNA sequence analysis revealed that this locus is similar to motility master regulatory operons of other gram-negative bacteria. Genetic complementation and functional analysis of flhDC indicated that it is required for the production of flagella. When flhDC was expressed from an inducible ptac promoter, flagellin production was shown to be dependent on levels of flhDC expression. Phenotypically, induction of the ptac-flhDC fusion also corresponded to increased levels of both swimming and swarming motility.  (+info)

Synthesis of the sigmaD protein is not sufficient to trigger expression of motility functions in Bacillus subtilis. (4/1391)

The gene encoding sigmaD, sigD, is transcribed from two promoter regions, the fla/che promoter region in front of the fla/che operon and PsigD directly in front of sigD. If sigmaD is translated from transcripts originating from PsigD, the cell is unable to express motility functions but synthesizes autolysins. Therefore, one function of the additional promoter is to allow the cell to express autolysins without expressing motility functions as well.  (+info)

Quantitative detection of Borrelia burgdorferi by real-time PCR. (5/1391)

Currently, no easy and reliable methods allowing for the quantification of Borrelia burgdorferi in tissues of infected humans or animals are available. Due to the lack of suitable assays to detect B. burgdorferi CFU and the qualitative nature of the currently performed PCR assays, we decided to exploit the recently developed real-time PCR. This technology measures the release of fluorescent oligonucleotides during the PCR. Flagellin of B. burgdorferi was chosen as the target sequence. A linear quantitative detection range of 5 logs with a calculated detection limit of one to three spirochetes per assay reaction mixture was observed. The fact that no signals were obtained with closely related organisms such as Borrelia hermsii argues for a high specificity of this newly developed method. A similar method was developed to quantify mouse actin genomic sequences to allow for the standardization of spirochete load. The specificity and sensitivity of the B. burgdorferi and the actin real-time PCR were not altered when samples were spiked with mouse cells or spirochetes, respectively. To evaluate the applicability of the real-time PCR, we used the mouse model of Lyme disease. The fate of B. burgdorferi was monitored in different tissues from inbred mice and from mice treated with antibiotics. Susceptible C3H/HeJ mice had markedly higher burdens of bacterial DNA than resistant BALB/c mice, and penicillin G treatment significantly reduced the numbers of spirochetes. Since these results show a close correlation between clinical symptoms and bacterial burden of tissues, we are currently analyzing human biopsy specimens to evaluate the real-time PCR in a diagnostic setting.  (+info)

One-step reverse transcriptase PCR method for detection of Borrelia burgdorferi mRNA in mouse Lyme arthritis tissue samples. (6/1391)

A one-step reverse transcriptase PCR (RT-PCR) method for detection of Borrelia burgdorferi mRNA in infected C3H mice is described. This simple procedure, less prone to nucleic acid cross-contamination than the standard method, was found to be 10-fold more sensitive than a classical two-step RT-PCR assay. By using one-step RT-PCR, flagellin mRNAs were detected in synovial and heart tissues from all seven infected mice tested.  (+info)

Population genetics and phylogenetic analysis of Colorado Borrelia burgdorferi. (7/1391)

Borrelia burgdorferi is transmitted in an enzootic cycle in Colorado between the tick Ixodes spinipalpis and the woodrat Neotoma mexicana. The genetic relationship of Colorado isolates to other B. burgdorferi isolates is unknown nor have relationships among various Colorado isolates been determined. Portions of the flagellin (fla), 66-kD protein, and outer surface protein A (ospA) genes were amplified from 71 Colorado isolates, screened for genetic variability using single strand conformation polymorphism analysis, and unique alleles were sequenced. Colorado isolates were most similar to tick isolates from California and New York isolate 25015. Genetic distances among Colorado ospA sequences were the same or higher than distances among other isolates whereas distances among fla sequences tended to be the same or lower. The index of association (I(A)) was calculated among all loci as a measure of clonality. The I(A) among Colorado isolates was similar to I(A) previously estimated among other United States isolates.  (+info)

Interaction of FliI, a component of the flagellar export apparatus, with flagellin and hook protein. (8/1391)

FliI is a key component of the flagellar export apparatus in Salmonella typhimurium. It catalyzes the hydrolysis of ATP which is necessary for flagellar assembly. Affinity blotting experiments showed that purified flagellin and hook protein, two flagellar axial proteins, interact specifically with FliI. The interaction of either of the two proteins with FliI, increases the intrinsic ATPase activity. The presence of either flagellin or hook protein stimulates ATPase activity in a specific and reversible manner. A Vmax of 0.12 nmol Pi min-1 microgram-1 and a Km for MgATP of 0.35 mM was determined for the unstimulated FliI; the presence of flagellin increased the Vmax to 0.35 nmol Pi min-1 microgram-1 and the Km for MgATP to 1.1 mM. The stimulation induced by the axial proteins was fully reversible suggesting a direct link between the catalytic activity of FliI and the export process.  (+info)

Flagellin is a protein that makes up the structural filament of the flagellum, which is a whip-like structure found on many bacteria that enables them to move. It is also known as a potent stimulator of the innate immune response and can be recognized by Toll-like receptor 5 (TLR5) in the host's immune system, triggering an inflammatory response. Flagellin is highly conserved among different bacterial species, making it a potential target for broad-spectrum vaccines and immunotherapies against bacterial infections.

Toll-like receptor 5 (TLR5) is a protein that plays a crucial role in the innate immune system. It is a type of transmembrane receptor located on the surface of various cells, including immune cells such as macrophages and dendritic cells. TLR5 recognizes and binds to a specific molecular pattern called flagellin, which is a structural protein found in the bacterial flagellum, a whip-like structure that some bacteria use for motility.

Once TLR5 binds to flagellin, it triggers a signaling cascade that leads to the activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs), which in turn activate genes involved in inflammation, immune response, and cell survival. This activation results in the production of proinflammatory cytokines and chemokines that help to recruit other immune cells to the site of infection and initiate an effective immune response against the invading pathogen.

TLR5 has been implicated in various inflammatory and infectious diseases, including Crohn's disease, sepsis, and Legionnaires' disease. Understanding the role of TLR5 in the immune system can provide insights into the development of new therapies for these conditions.

Flagella are long, thin, whip-like structures that some types of cells use to move themselves around. They are made up of a protein called tubulin and are surrounded by a membrane. In bacteria, flagella rotate like a propeller to push the cell through its environment. In eukaryotic cells (cells with a true nucleus), such as sperm cells or certain types of algae, flagella move in a wave-like motion to achieve locomotion. The ability to produce flagella is called flagellation.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

"Salmonella enterica" serovar "Typhimurium" is a subspecies of the bacterial species Salmonella enterica, which is a gram-negative, facultatively anaerobic, rod-shaped bacterium. It is a common cause of foodborne illness in humans and animals worldwide. The bacteria can be found in a variety of sources, including contaminated food and water, raw meat, poultry, eggs, and dairy products.

The infection caused by Salmonella Typhimurium is typically self-limiting and results in gastroenteritis, which is characterized by symptoms such as diarrhea, abdominal cramps, fever, and vomiting. However, in some cases, the infection can spread to other parts of the body and cause more severe illness, particularly in young children, older adults, and people with weakened immune systems.

Salmonella Typhimurium is a major public health concern due to its ability to cause outbreaks of foodborne illness, as well as its potential to develop antibiotic resistance. Proper food handling, preparation, and storage practices can help prevent the spread of Salmonella Typhimurium and other foodborne pathogens.

Salmonella is a genus of rod-shaped, Gram-negative bacteria that are facultative anaerobes and are motile due to peritrichous flagella. They are non-spore forming and often have a single polar flagellum when grown in certain conditions. Salmonella species are important pathogens in humans and other animals, causing foodborne illnesses known as salmonellosis.

Salmonella can be found in the intestinal tracts of humans, birds, reptiles, and mammals. They can contaminate various foods, including meat, poultry, eggs, dairy products, and fresh produce. The bacteria can survive and multiply in a wide range of temperatures and environments, making them challenging to control completely.

Salmonella infection typically leads to gastroenteritis, characterized by symptoms such as diarrhea, abdominal cramps, fever, and vomiting. In some cases, the infection may spread beyond the intestines, leading to more severe complications like bacteremia (bacterial infection of the blood) or focal infections in various organs.

There are two main species of Salmonella: S. enterica and S. bongori. S. enterica is further divided into six subspecies and numerous serovars, with over 2,500 distinct serotypes identified to date. Some well-known Salmonella serovars include S. Typhi (causes typhoid fever), S. Paratyphi A, B, and C (cause paratyphoid fever), and S. Enteritidis and S. Typhimurium (common causes of foodborne salmonellosis).

'Campylobacter jejuni' is a gram-negative, spiral-shaped bacterium that is a common cause of foodborne illness worldwide. It is often found in the intestines of warm-blooded animals, including birds and mammals, and can be transmitted to humans through contaminated food or water.

The bacteria are capable of causing an infection known as campylobacteriosis, which is characterized by symptoms such as diarrhea, abdominal cramps, fever, and vomiting. In severe cases, the infection can spread to the bloodstream and cause serious complications, particularly in individuals with weakened immune systems.

'Campylobacter jejuni' is one of the most common causes of foodborne illness in the United States, with an estimated 1.3 million cases occurring each year. It is often found in undercooked poultry and raw or unpasteurized milk products, as well as in contaminated water supplies. Proper cooking and pasteurization can help reduce the risk of infection, as can good hygiene practices such as washing hands thoroughly after handling raw meat and vegetables.

A bacterial gene is a segment of DNA (or RNA in some viruses) that contains the genetic information necessary for the synthesis of a functional bacterial protein or RNA molecule. These genes are responsible for encoding various characteristics and functions of bacteria such as metabolism, reproduction, and resistance to antibiotics. They can be transmitted between bacteria through horizontal gene transfer mechanisms like conjugation, transformation, and transduction. Bacterial genes are often organized into operons, which are clusters of genes that are transcribed together as a single mRNA molecule.

It's important to note that the term "bacterial gene" is used to describe genetic elements found in bacteria, but not all genetic elements in bacteria are considered genes. For example, some DNA sequences may not encode functional products and are therefore not considered genes. Additionally, some bacterial genes may be plasmid-borne or phage-borne, rather than being located on the bacterial chromosome.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

NAIP (Neuronal Apoptosis Inhibitory Protein) is a protein involved in inhibiting programmed cell death, also known as apoptosis. It is a member of the inhibitor of apoptosis (IAP) family and is primarily expressed in neurons. NAIP plays a crucial role in preventing excessive cell death during nervous system development and after nerve injury. It functions by binding to and inhibiting certain caspases, which are enzymes that play an essential role in initiating and executing apoptosis. Mutations in the gene encoding NAIP have been associated with neurodegenerative disorders such as spinal muscular atrophy and amyotrophic lateral sclerosis (ALS).

Toll-like receptors (TLRs) are a type of pattern recognition receptors (PRRs) that play a crucial role in the innate immune system. They are transmembrane proteins located on the surface of various immune cells, including macrophages, dendritic cells, and B cells. TLRs recognize specific patterns of molecules called pathogen-associated molecular patterns (PAMPs) that are found on microbes such as bacteria, viruses, fungi, and parasites.

Once TLRs bind to PAMPs, they initiate a signaling cascade that activates the immune response, leading to the production of cytokines and chemokines, which in turn recruit and activate other immune cells. TLRs also play a role in the adaptive immune response by activating antigen-presenting cells and promoting the differentiation of T cells.

There are ten known human TLRs, each with distinct ligand specificity and cellular localization. TLRs can be found on the cell surface or within endosomes, where they recognize different types of PAMPs. For example, TLR4 recognizes lipopolysaccharides (LPS) found on gram-negative bacteria, while TLR3 recognizes double-stranded RNA from viruses.

Overall, TLRs are critical components of the immune system's ability to detect and respond to infections, and dysregulation of TLR signaling has been implicated in various inflammatory diseases and cancers.

The Borrelia burgdorferi group, also known as the Borrelia burgdorferi sensu lato (s.l.) complex, refers to a genetically related group of spirochetal bacteria that cause Lyme disease and other related diseases worldwide. The group includes several species, with Borrelia burgdorferi sensu stricto (s.s.), B. afzelii, and B. garinii being the most common and best studied. These bacteria are transmitted to humans through the bite of infected black-legged ticks (Ixodes scapularis in the United States and Ixodes pacificus on the West Coast; Ixodes ricinus in Europe).

Lyme disease is a multisystem disorder that can affect the skin, joints, nervous system, and heart. Early symptoms typically include a characteristic expanding rash called erythema migrans, fever, fatigue, headache, and muscle and joint pain. If left untreated, the infection can spread to other parts of the body and cause more severe complications, such as arthritis, neurological problems, and carditis.

Diagnosis of Lyme disease is based on a combination of clinical symptoms, exposure history, and laboratory tests. Treatment usually involves antibiotics, such as doxycycline, amoxicillin, or ceftriaxone, and is generally most effective when initiated early in the course of the illness. Preventive measures, such as using insect repellent, checking for ticks after being outdoors, and promptly removing attached ticks, can help reduce the risk of Lyme disease and other tick-borne infections.

"Pseudomonas aeruginosa" is a medically important, gram-negative, rod-shaped bacterium that is widely found in the environment, such as in soil, water, and on plants. It's an opportunistic pathogen, meaning it usually doesn't cause infection in healthy individuals but can cause severe and sometimes life-threatening infections in people with weakened immune systems, burns, or chronic lung diseases like cystic fibrosis.

P. aeruginosa is known for its remarkable ability to resist many antibiotics and disinfectants due to its intrinsic resistance mechanisms and the acquisition of additional resistance determinants. It can cause various types of infections, including respiratory tract infections, urinary tract infections, gastrointestinal infections, dermatitis, and severe bloodstream infections known as sepsis.

The bacterium produces a variety of virulence factors that contribute to its pathogenicity, such as exotoxins, proteases, and pigments like pyocyanin and pyoverdine, which aid in iron acquisition and help the organism evade host immune responses. Effective infection control measures, appropriate use of antibiotics, and close monitoring of high-risk patients are crucial for managing P. aeruginosa infections.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Interleukin-8 (IL-8) is a type of cytokine, which is a small signaling protein involved in immune response and inflammation. IL-8 is also known as neutrophil chemotactic factor or NCF because it attracts neutrophils, a type of white blood cell, to the site of infection or injury.

IL-8 is produced by various cells including macrophages, epithelial cells, and endothelial cells in response to bacterial or inflammatory stimuli. It acts by binding to specific receptors called CXCR1 and CXCR2 on the surface of neutrophils, which triggers a series of intracellular signaling events leading to neutrophil activation, migration, and degranulation.

IL-8 plays an important role in the recruitment of neutrophils to the site of infection or tissue damage, where they can phagocytose and destroy invading microorganisms. However, excessive or prolonged production of IL-8 has been implicated in various inflammatory diseases such as chronic obstructive pulmonary disease (COPD), rheumatoid arthritis, and cancer.

Innate immunity, also known as non-specific immunity or natural immunity, is the inherent defense mechanism that provides immediate protection against potentially harmful pathogens (like bacteria, viruses, fungi, and parasites) without the need for prior exposure. This type of immunity is present from birth and does not adapt to specific threats over time.

Innate immune responses involve various mechanisms such as:

1. Physical barriers: Skin and mucous membranes prevent pathogens from entering the body.
2. Chemical barriers: Enzymes, stomach acid, and lysozyme in tears, saliva, and sweat help to destroy or inhibit the growth of microorganisms.
3. Cellular responses: Phagocytic cells (neutrophils, monocytes, macrophages) recognize and engulf foreign particles and pathogens, while natural killer (NK) cells target and eliminate virus-infected or cancerous cells.
4. Inflammatory response: When an infection occurs, the innate immune system triggers inflammation to increase blood flow, recruit immune cells, and remove damaged tissue.
5. Complement system: A group of proteins that work together to recognize and destroy pathogens directly or enhance phagocytosis by coating them with complement components (opsonization).

Innate immunity plays a crucial role in initiating the adaptive immune response, which is specific to particular pathogens and provides long-term protection through memory cells. Both innate and adaptive immunity work together to maintain overall immune homeostasis and protect the body from infections and diseases.

Gene expression regulation in bacteria refers to the complex cellular processes that control the production of proteins from specific genes. This regulation allows bacteria to adapt to changing environmental conditions and ensure the appropriate amount of protein is produced at the right time.

Bacteria have a variety of mechanisms for regulating gene expression, including:

1. Operon structure: Many bacterial genes are organized into operons, which are clusters of genes that are transcribed together as a single mRNA molecule. The expression of these genes can be coordinately regulated by controlling the transcription of the entire operon.
2. Promoter regulation: Transcription is initiated at promoter regions upstream of the gene or operon. Bacteria have regulatory proteins called sigma factors that bind to the promoter and recruit RNA polymerase, the enzyme responsible for transcribing DNA into RNA. The binding of sigma factors can be influenced by environmental signals, allowing for regulation of transcription.
3. Attenuation: Some operons have regulatory regions called attenuators that control transcription termination. These regions contain hairpin structures that can form in the mRNA and cause transcription to stop prematurely. The formation of these hairpins is influenced by the concentration of specific metabolites, allowing for regulation of gene expression based on the availability of those metabolites.
4. Riboswitches: Some bacterial mRNAs contain regulatory elements called riboswitches that bind small molecules directly. When a small molecule binds to the riboswitch, it changes conformation and affects transcription or translation of the associated gene.
5. CRISPR-Cas systems: Bacteria use CRISPR-Cas systems for adaptive immunity against viruses and plasmids. These systems incorporate short sequences from foreign DNA into their own genome, which can then be used to recognize and cleave similar sequences in invading genetic elements.

Overall, gene expression regulation in bacteria is a complex process that allows them to respond quickly and efficiently to changing environmental conditions. Understanding these regulatory mechanisms can provide insights into bacterial physiology and help inform strategies for controlling bacterial growth and behavior.

Bacterial antigens are substances found on the surface or produced by bacteria that can stimulate an immune response in a host organism. These antigens can be proteins, polysaccharides, teichoic acids, lipopolysaccharides, or other molecules that are recognized as foreign by the host's immune system.

When a bacterial antigen is encountered by the host's immune system, it triggers a series of responses aimed at eliminating the bacteria and preventing infection. The host's immune system recognizes the antigen as foreign through the use of specialized receptors called pattern recognition receptors (PRRs), which are found on various immune cells such as macrophages, dendritic cells, and neutrophils.

Once a bacterial antigen is recognized by the host's immune system, it can stimulate both the innate and adaptive immune responses. The innate immune response involves the activation of inflammatory pathways, the recruitment of immune cells to the site of infection, and the production of antimicrobial peptides.

The adaptive immune response, on the other hand, involves the activation of T cells and B cells, which are specific to the bacterial antigen. These cells can recognize and remember the antigen, allowing for a more rapid and effective response upon subsequent exposures.

Bacterial antigens are important in the development of vaccines, as they can be used to stimulate an immune response without causing disease. By identifying specific bacterial antigens that are associated with virulence or pathogenicity, researchers can develop vaccines that target these antigens and provide protection against infection.

There is no established medical definition for "Pseudomonas vaccines" as it generally refers to vaccines that are being developed to prevent infections caused by the bacterium *Pseudomonas aeruginosa*. This bacterium can cause various types of infections, particularly in individuals with weakened immune systems or underlying health conditions.

*Pseudomonas aeruginosa* is an opportunistic pathogen, which means it mainly causes infection in people who have weakened defenses. It's known for its ability to develop resistance to multiple antibiotics, making it a significant concern in healthcare settings.

Vaccines against *Pseudomonas aeruginosa* aim to stimulate the immune system to produce an immune response (the production of antibodies and activation of immune cells) that can protect against future infection by this bacterium. Several vaccine candidates are being researched, targeting various antigens on the surface of *Pseudomonas aeruginosa*. However, none have been licensed for widespread use yet.

In summary, 'Pseudomonas vaccines' refers to vaccines under development that aim to protect against infections caused by the bacterium *Pseudomonas aeruginosa*.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

The helical N- and C-termini of flagellin form the inner core of the flagellin protein, and is responsible for flagellin's ... Flagellin at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Bacterial flagellin and plant disease ... Flagellin perception in Arabidopsis thaliana functions via the receptor-like-kinase FLS2 (FLAGELLIN SENSING 2). Upon flg22 ... The propensity of the immune response to flagellin may be explained by two facts: Flagellin is an extremely abundant protein in ...
... flagellin; K antigen: capsule), e.g. O157:H7). It is, however, common to cite only the serogroup, i.e. the O-antigen. At ...
Flagellin is glycosylated. The bacterial flagella's existence depends upon the pH. The rumen pH is about 5.5 to 7. The medium ...
Lu J, Sun PD (March 2012). "The structure of the TLR5-flagellin complex: a new mode of pathogen detection, conserved receptor ... Mueller, K. L. (2012). "Flagellin Takes Its Toll". Science Signaling. 5 (212): ec62. Bibcode:2012Sci...335T.774.. doi:10.1126/ ... "Activation of Toll-like receptor 5 on breast cancer cells by flagellin suppresses cell proliferation and tumor growth". Cancer ... "Structural basis of TLR5-flagellin recognition and signaling". Science. 335 (6070): 859-64. Bibcode:2012Sci...335..859Y. doi: ...
With Toxoplasma its ligand is the protein profilin and the ligand for E. coli is flagellin. The flagellin from the ... Flagellin, a TLR5 ligand, induces cytokine secretion on interacting with TLR5 on human T cells. TLRs are a type of pattern ... Other molecules (bacterial lipopeptides, flagellin, and unmethylated DNA) were shown in turn to provoke host responses that are ... proteins such as flagellin from bacterial flagella; double-stranded RNA of viruses; or the unmethylated CpG islands of ...
Plants perceive flagellin when it binds to the receptor FLS2. When flagellin is perceived by FLS2, this strongly promotes the ... In addition to flagellin, plants are also able to perceive other bacterial effectors. One of these, EF-Tu is perceived by the ... Chinchilla D, Zipfel C, Robatzek S, Kemmerling B, Nürnberger T, Jones JD, Felix G, Boller T (July 2007). "A flagellin-induced ... "BR-Signaling Kinase 1 physically associates with Flagellin Sensing 2 and regulates plant innate immunity in Arabidopsis". The ...
The best-characterized PRR in A. thaliana is FLS2 (Flagellin-Sensing2), which recognizes bacterial flagellin, a specialized ... FLS2 shows striking similarity to rice XA21, the first PRR isolated in 1995.[citation needed] Both flagellin and UV-C act ... Gómez-Gómez L, Felix G, Boller T (May 1999). "A single locus determines sensitivity to bacterial flagellin in Arabidopsis ... They contain two receptors, FLS2 (bacterial flagellin receptor) and EF-Tu (bacterial EF-Tu protein), which use signal ...
"Bacterial disease resistance in Arabidopsis through flagellin perception". Nature. 428 (6984): 764-767. Bibcode:2004Natur.428.. ...
The effects of ultra-low doses of flagellin". Immunology. 14 (2): 273-284. PMC 1409291. PMID 5640947. H. N. Claman; E. A. ...
Even so, further studies have shown a second FLS gene known as FLS2 that is also associated with flagellin reception. FLS2 and ... It is in this region, which is the amino-terminus, where it is said to have direct interaction with flagellin initiating the ... As discovered by the ectopic expression of FLS2 study, FLS2 is directed related to flagellin perception, so by discovery and by ... FLS genes have been discovered to be involved in flagellin reception of bacteria. FLS1 was the original gene discovered shown ...
The S. meliloti genome contains four genes coding for flagellin. These include fliC1C2-fliC3C4. The genome contains three ...
Faguy DM, Jarrell KF, Kuzio J, Kalmokoff ML (January 1994). "Molecular analysis of archael flagellins: similarity to the type ... Similarly, flagella grow by exporting flagellin through the flagellar machinery. It is hypothesised that the flagellum evolved ...
IPAF senses flagellin from Salmonella typhimurium, Pseudomonas aeruginosa, Listeria monocytogenes. Toll-like receptor ...
Like EFR, FLS2 (flagellin-sensing 2) is a plant receptor-like kinase that acts as a PRR in the plant innate immune system. ... EF-Tu FLS2 Flagellin Arabidopsis thaliana "PDB-101: Elongation Factors". pdb101.rcsb.org. Retrieved 2017-10-09. Zipfel, Cyril; ... Instead of binding to EF-Tu, it binds to flagellin, another highly conserved structure present on many pathogens. It, like EF- ... an LRR receptor-like kinase involved in the perception of the bacterial elicitor flagellin in Arabidopsis". Molecular Cell. 5 ( ...
This strain's genes express flagellin, which triggers the human immune response; so it was not a bubonic plague. Because of its ...
Wang L; Rothemund D; Reeves PR (May 2003). "Species-Wide Variation in the Escherichia coli Flagellin (H-Antigen) Gene". Journal ... flagellin For example, E. coli strain EDL933 is of the O157:H7 group. The outer membrane of an E. coli cell contains millions ...
The bacterial flagellum is made up of protein subunits of flagellin. Its shape is a 20-nanometer-thick hollow tube. It is ... Bacterial flagella grow by the addition of flagellin subunits at the tip; archaeal flagella grow by the addition of subunits to ... In vitro, flagellar filaments assemble spontaneously in a solution containing purified flagellin as the sole protein. At least ... inside that the flagellin subunits can flow up the inside of the filament and get added at the tip; the archaellum is too thin ...
There are highly conserved regions in the flagellin protein among all bacteria, facilitating the recognition of flagellin by a ... TLR5 recognizes flagellin, which is the protein monomer that makes up the filament of bacterial flagella, found on nearly all ... Flagellin, which is a TLR5-activating ligand, is present in synovial fluid from patients with rheumatoid arthritis. Activation ... TLR5 recognizes bacterial flagellin, a principal component of bacterial flagella and a virulence factor. The activation of this ...
"Anti-flagellin antibodies inhibit motility in Roseburia intestinalis and Clostridium ramosum." (2013). Mirande, C.; Kadlecikova ...
This strain's genes express flagellin, which triggers the human immune response. However, by contrast with other prehistoric ... Yersinia pestis bacteria, the strain does so weakly; later, historic plague does not express flagellin at all, accounting for ...
"Cytosolic recognition of flagellin by mouse macrophages restricts Legionella pneumophila infection". Journal of Experimental ...
For example, NLR proteins NLRC4 can recognise flagellin and type III secretion system components. NLRP3 is activated by ... September 2011). "The NLRC4 inflammasome receptors for bacterial flagellin and type III secretion apparatus". Nature. 477 (7366 ...
Zhong, Maohua; Yan, Huimin; Li, Yaoming (October 2017). "Flagellin: a unique microbe-associated molecular pattern and a multi- ... The protein structure that makes up the flagellar filament, flagellin, is conserved among all flagellated bacteria. Vertebrates ...
Studies have been conducted on TLR11 as well, and it has been shown that it recognizes flagellin and profilin-like proteins in ... Hatai H, Lepelley A, Zeng W, Hayden MS, Ghosh S (2016-02-09). "Toll-Like Receptor 11 (TLR11) Interacts with Flagellin and ... Since that time two other plants PRRs, Arabidopsis FLS2 (flagellin) and EFR (elongation factor Tu receptor)have been isolated. ... flagellin, microtubule elongation factors), peptidoglycans and lipoteichoic acids (from Gram-positive bacteria), N- ...
Zhao Y, Shao F (May 2015). "The NAIP-NLRC4 inflammasome in innate immune detection of bacterial flagellin and type III ... as well as flagellin, the molecular building block of flagella (NAIP5 and 6). In humans, there is only one NAIP, and it ... "Inflammasome activation restricts Legionella pneumophila replication in primary microglial cells through flagellin detection". ...
Hatai H, Lepelley A, Zeng W, Hayden MS, Ghosh S (2016). "Toll-Like Receptor 11 (TLR11) Interacts with Flagellin and Profilin ... In mice, TLR11 has been shown to recognise (bacterial) flagellin and (eukaryotic) profilin present on certain microbes, it ... and likely many other species due to the highly conserved nature of flagellin and profilin. Proteins in the TLR family are ...
... genetic and functional characterization of the flagellin glycosylation process in Helicobacter pylori". Molecular Microbiology ...
Chinchilla D, Zipfel C, Robatzek S, Kemmerling B, Nürnberger T, Jones JD, Felix G, Boller T (July 2007). "A flagellin-induced ... FLS2 acts as a detector of the bacterial protein flagellin and is important for plant immunity. Surprisingly (given their ... an LRR receptor-like kinase involved in the perception of the bacterial elicitor flagellin in Arabidopsis". Molecular Cell. 5 ( ...
... genetic and functional characterization of the flagellin glycosylation process in Helicobacter pylori". Molecular Microbiology ...
Once an adaptive response has been mounted against one type of flagellin, or if a previous encounter has left the adaptive ... Salmonella use this technique to switch between different types of the protein flagellin. As a result, flagella with different ... or more complicated by involving multiple genes in the expression of multiple types of flagellin by S. typhimurium. Fimbrial ... immune system ready to deal with one type of flagellin, switching types renders previously high affinity antibodies, TCRs, and ...
The helical N- and C-termini of flagellin form the inner core of the flagellin protein, and is responsible for flagellins ... Flagellin at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Bacterial flagellin and plant disease ... Flagellin perception in Arabidopsis thaliana functions via the receptor-like-kinase FLS2 (FLAGELLIN SENSING 2). Upon flg22 ... The propensity of the immune response to flagellin may be explained by two facts: Flagellin is an extremely abundant protein in ...
We show, in mice, that repeated injection of flagellin elicits increases in fecal anti-flagellin IgA and alterations in ... obese subjects exhibit increased levels of fecal flagellin and reduced levels of fecal flagellin-specific IgA, relative to ... Thus, administration of flagellin, and perhaps other pathobiont antigens, may confer some protection against chronic ... Here, we set out to investigate whether elicitation of mucosal anti-flagellin antibodies by direct administration of purified ...
Almost all seropositive patients in both early and late stage LB had serum antibodies against flagellin, but antibodies to OspA ... Cellular immune reactivities to flagellin were significantly higher only in early LB compared with both control groups. ... Cellular immune reactivity to recombinant OspA and flagellin from Borrelia burgdorferi in patients with Lyme borreliosis. ... Cellular immune reactivity to recombinant OspA and flagellin from Borrelia burgdorferi in patients with Lyme borreliosis. ...
Multiple strains of colitic mice had elevated serum anti-flagellin IgG2a responses and Th1 T cell responses to flagellin. In ... Serum IgG to these flagellins, but not to the dissimilar Salmonella muenchen flagellin, was elevated in patients with Crohn ... Bacterial flagellin is a dominant antigen in Crohn disease J Clin Invest. 2004 May;113(9):1296-306. doi: 10.1172/JCI20295. ... These results identify flagellins as a class of immunodominant antigens that stimulate pathogenic intestinal immune reactions ...
... Breaking the rules: flagellin vs rotavirus. Flagellin is a bacterial protein that activates the innate immune system ... Flagellin can protect against all those things (in mice, of course)? What about bullets or heartbreak? What is flagellin? ... A versatile protective agent: flagellin. Flagellin treatment protects against chemicals, bacteria, viruses and radiation ... Flagellin is the main structural component of flagella, the miniature whips bacteria use to propel themselves. Several Emory ...
S.N Flagella S.N Pili 1. These are helical structures but are not straight. 1. These are non-helical structures but are straight. 2. These are long ...
flagellin. . This particular protein plays an important role in driving. bacterial cell movement, which can potentially trigger ... Why target the protein flagellin? For this study, Dr. Benoit Chassaing, Inserm principal investigator at the Institut Cochin, ... Using a mouse model, the researchers trained the mices mucosal immune system in the gut to target flagellin, granting it ... Chassaing explained when asked why they decided to focus on flagellin. "And we know that flagella - (a) filamentous appendix ...
Flagellin: BD. SMTL:PDB. SMTL Chain Id:. PDB Chain Id:. A. A ...
and what flagellin does once it gets there. And no one yet knows how this type of salmonella bacteria allows flagellin to break ... Since flagellin is conserved in many microorganisms, Galan adds that flagellin may act as a basic signal to alert the immune ... missing the flagellin gene. They cells didnt secrete IL-8. When they injected flagellin from other bacteria into the far-gut ... flagellin may act as a basic signal to alert the immune system to the presence of bacteria..... Report: Salmonellas dirty ...
上海恒遠生物科技有限公司所提供的人flagellin ELISA試劑盒質量可 ... 當前位置:主頁 > 產品中心 > 酶聯免疫試劑盒 > 人酶聯免疫試劑盒 >人flagellin ELISA試劑盒 ... "人flagellin
... silent flagellin, that binds to the immune receptor Toll-like receptor 5 without inducing a pro-inflammatory response. ... Researchers from the Max Planck Institute for Biology Tübingen have identified a new type of flagellin in the human gut, termed ... Therefore, the scientists termed this new flagellin variant silent flagellins. Previously, flagellin binding to TLR5 was ... These flagellins showed strong binding to TLR5, similar to flagellins from pathogens, but failed to trigger an inflammatory ...
Flagellin gene. FAM-AAC GGC ACA TAT TCA GAT GCA GAC-TAMRA. (7). ... Flagellin GAA TTA GCA GTT CAA TCA GG. (7). BorR. Flagellin TTC ...
Flagellin-Stimulated Production of Interferon-beta Promotes Anti-Flagellin IgG2c and IgA Responses. -. dc.type. Article. -. dc. ... anti-flagellin antibody. -. dc.subject.keywordAuthor. flagellin. -. dc.subject.keywordAuthor. IgA. -. dc.subject.keywordAuthor ... Flagellin can also serve as a specific antigen for the adaptive immune system and stimulate anti-flagellin antibody responses. ... Flagellin-Stimulated Production of Interferon-beta Promotes Anti-Flagellin IgG2c and IgA Responses. ...
flg22, Flagellin Fragment - 1 mg. Cat.Number : AS-62633 $215.00 Excl. Tax ...
Structural basis for specific flagellin recognition by the NLR protein NAIP5. In: Cell Research. 2018 ; Vol. 28, No. 1. pp. 35- ... Structural basis for specific flagellin recognition by the NLR protein NAIP5. / Yang, Xinru; Yang, Fan; Wang, Weiguang et al. ... Structural basis for specific flagellin recognition by the NLR protein NAIP5. Cell Research. 2018 Jan 1;28(1):35-47. doi: ... Structural basis for specific flagellin recognition by the NLR protein NAIP5. Xinru Yang, Fan Yang, Weiguang Wang, Guangzhong ...
Suppression of citrus canker disease mediated by flagellin perception. Suppression of citrus canker disease mediated by ... Citrus sinensis; FliC; Xanthomonas citri; Xanthomonas aurantifolii pathotype C; citrus canker; flagellin C; flgIII-20; flgIII- ... we herein report that the Xa flagellin C protein (XaFliC) acts as a potent defence elicitor in sweet oranges. Just as Xa ... flagellin perception. Andrade, Maxuel de Oliveira; da Silva, Jaqueline Cristina; Soprano, Adriana Santos; Shimo, Hugo ...
Creation and purification of alanine point mutant flagellins. The fliC gene, which encodes flagellin, was cloned into the NcoI ... Amino acids on flagellin previously determined to be important for TLR5 recognition are shown in red on the flagellin structure ... Amino acids on flagellin previously determined to be important for TLR5 recognition are shown in red on the flagellin structure ... Wild-type flagellin precipitated human TLR5 more efficiently than the R90A flagellin mutant, whereas wild-type and R90A ...
Flagellins lacking TLR5 or NLRC4 activation domains were used to assess their contribution to protection. RESULTS: Sublingual ... Sublingual flagellin protects against acute pneumococcal pneumonia in a TLR5-dependent and NLRC4-independent fashion.. ... Flagellin-stimulated lung epithelial cells recapitulated the lungs transcriptional profile suggesting they could be targeted ... Natalia Muñoz-Wolf, Analía Rial, Delphine Fougeron, Julien Tabareau, Jean-Claude Sirard, et al.. Sublingual flagellin protects ...
Flagellin is a P. aeruginosa virulence factor involved in host response to this pathogen. We examined the role of flagellin in ... Finally, inhibition of ERK abolished the expression of both PAK- and flagellin-induced MUC5AC. We conclude that: (i) flagellin ... A crucial role of Flagellin in the induction of airway mucus production by Pseudomonas aeruginosa. ... A purified P. aeruginosa flagellin induced MUC5AC expression in parallel to IL-8 secretion in NCI-H292 cells. Accordingly, ...
Study describes IgG antibodies in Crohns disease specific for human bacterial flagellins Last year, Charles O. Elson, M.D., ... He used a mouse model that included immune-reactive T cells from patients with Crohns disease in a flagellin peptide-specific ...
Thermus thermophilus HB8 flagellin protein (FliC) is encoded by the TTHC004 (fliC) gene, which is located in the pTT8 plasmid ... T1 - Flagellin gene (fliC) of Thermus thermophilus HB8. T2 - Characterization of its product and involvement to flagella ... Flagellin gene (fliC) of Thermus thermophilus HB8: Characterization of its product and involvement to flagella assembly and ... Flagellin gene (fliC) of Thermus thermophilus HB8: Characterization of its product and involvement to flagella assembly and ...
Table 2 Homologues of LI0570 in the amino acid sequence of flagellin associated protein searched by the BlastP program Full ... Sequence alignments of LI0570 and other flagellin-associated proteins using the CLUSTALW alignment program. An asterisk (*) ... Flagellin, a TLR5 agonist, is a potent activator of the innate immune system. To evaluate the immune stimulatory capacity of ... Bacterial flagellin, a pathogen-associated molecular pattern (PAMP), binds to TLR5 on the surface of dendritic cells (DC) or ...
Dive into the research topics of Decrease in expression of the master operon of flagellin synthesis in a dnaA46 mutant of ... Decrease in expression of the master operon of flagellin synthesis in a dnaA46 mutant of Escherichia coli. ...
... flagellin-specific chaperone (FliS); 26, flagellar hook-associated protein (FliD); 27, flagellin protein (FliC); 28, ...
Cytosolic recognition of flagellin by mouse macrophages restricts Legionella pneumophila infection. J. Exp. Med. 203, 1093-1104 ... Cytoplasmic flagellin activates caspase-1 and secretion of interleukin 1β via Ipaf. Nature Immunol. 7, 569-575 (2006) ... Cytosolic flagellin requires Ipaf for activation of caspase-1 and interleukin 1β in Salmonella-infected macrophages. Nature ... Ren, T., Zamboni, D. S., Roy, C. R., Dietrich, W. F. & Vance, R. E. Flagellin-deficient Legionella mutants evade caspase-1-and ...
A flagellin-induced complex of the receptor FLS2 and BAK1 initiates plant defence p.497 doi: 10.1038/nature05999 ...
Vaccine constructs consisting of antigen-flagellin fusions induce balanced Th1 and Th2 responses [87]. Flagellin has already ... Nguyen, C.T.; Hong, S.H.; Sin, J.I.; Vu, H.V.; Jeong, K.; Cho, K.O.; Uematsu, S.; Akira, S.; Lee, S.E.; Rhee, J.H. Flagellin ... Mizel, S.B.; Bates, J.T. Flagellin as an adjuvant: Cellular mechanisms and potential. J. Immunol. 2010, 185, 5677-5682. [Google ... TLR5 is a membrane-based receptor for bacterial flagellin. ... CD8+ T cell adjuvant effects of Salmonella FliCd flagellin in ...
2004). Bacterial disease resistance in Arabidopsis through flagellin perception. Nature 428, 764. doi: 10.1038/nature02485 ...
  • Flagellin has also been shown to directly interact with TLR5 on T cells and TLR11. (wikipedia.org)
  • There exists a specific innate immune receptor that recognizes flagellin, Toll-like receptor 5 (TLR5). (wikipedia.org)
  • The link between elevated microbiota flagellin levels and intestinal inflammation is thought to involve flagellin's ability to activate pro-inflammatory gene expression via TLR5 and the NLRC4 inflammasome. (nature.com)
  • The dominant antigens identified were flagellins, molecules known to activate innate immunity via Toll-like receptor 5 (TLR5), and critical targets of the acquired immune system in host defense. (nih.gov)
  • One of these is Toll-like receptor 5 (TLR5): it binds flagellin, the protein that makes up the bacterial flagellum, which bacteria use to swim. (the-microbiologist.com)
  • Once bound to flagellin, TLR5 induces a pro-inflammatory immune response. (the-microbiologist.com)
  • While some bacteria avoid TLR5 by producing flagellins that no longer bind the receptor, previous research showed that so-called commensal bacteria, which are harmless to their human hosts, produce flagellins with intact binding sites. (the-microbiologist.com)
  • By screening 116 different flagellins for both TLR5 activation and binding, the researchers found that roughly half were unlike previously described flagellins. (the-microbiologist.com)
  • These flagellins showed strong binding to TLR5, similar to flagellins from pathogens, but failed to trigger an inflammatory response. (the-microbiologist.com)
  • Previously, flagellin binding to TLR5 was thought to be sufficient to activate the inflammatory response. (the-microbiologist.com)
  • The discovery that commensals produce flagellins that bind TLR5 without initiating an immune response challenges the prior understanding of how TLR5 is turned on. (the-microbiologist.com)
  • We now know that bacterial flagellin can interact with TLR5 at least three in different ways: bind and induce an immune response, bind and not induce an immune response, and evade by not binding," explains Ruth Ley, senior author of the study and director of the Department of Microbiome Science at the Max Planck Institute for Biology Tübingen. (the-microbiologist.com)
  • Subsequent metagenomic analyses showed that silent flagellins are very common in the human gut and therefore represent "a substantial, previously unappreciated, yet physiologically relevant, population of TLR5 binding proteins," says Sara Clasen, first author of the study. (the-microbiologist.com)
  • Flagellin, a major structural protein of the flagellum found in all motile bacteria, activates the TLR5- or NLRC4 inflammasome-dependent signaling pathway to induce innate immune responses. (kaist.ac.kr)
  • Failure to recognize commensal-derived flagellin in TLR5-deficient mice leads to the reduction in antiflagellin IgA antibodies at steady state and causes microbial dysbiosis and mucosal barrier breach by flagellated bacteria to promote chronic intestinal inflammation. (kaist.ac.kr)
  • In this study, we show that flagellin induces interferon-beta (IFN-beta) production and subsequently activates type I IFN receptor signaling in a TLR5- and MyD88-dependent manner in vitro and in vivo. (kaist.ac.kr)
  • Sublingual flagellin protects against acute pneumococcal pneumonia in a TLR5-dependent and NLRC4-independent fashion. (hal.science)
  • Flagellins lacking TLR5 or NLRC4 activation domains were used to assess their contribution to protection. (hal.science)
  • RESULTS: Sublingual flagellin protected mice in a TLR5-dependent, NLRC4-independent fashion. (hal.science)
  • Silencing of TLR5 and Naip, siRNA inhibited both flagellin-induced MUC5AC expression and IL-8 secretion. (pasteur.fr)
  • We demonstrate that mouse and human TLR5 discriminate between different flagellins, and we use this difference to map the flagellin recognition site on TLR5 to 228 amino acids of the extracellular domain. (silverchair.com)
  • Mutagenesis studies demonstrate that naturally occurring amino acid variation in TLR5 residue 268 is responsible for human and mouse discrimination between flagellin molecules. (silverchair.com)
  • These studies localize flagellin recognition to a conserved surface on the modeled TLR5 structure, providing detailed analysis of the interaction of a TLR with its ligand. (silverchair.com)
  • We previously demonstrated that TLR5 recognizes bacterial flagellin ( 3 ), the most abundant protein found in the whip-like structures that propel bacteria ( 4 ). (silverchair.com)
  • We defined flagellin as a prototypical pathogen-associated molecular pattern by identifying the 13 amino acids on flagellin that are involved in TLR5 recognition ( 5 ). (silverchair.com)
  • The TLR5 recognition site on flagellin is located on the convex surface of the flagellin monomer that contacts adjacent monomers when they stack in the flagellar filament. (silverchair.com)
  • It is also known that the bacterial protein flagellin effectively induces an innate immune response of the host that is mediated by its ability to bind to toll-like receptor 5 (TLR5). (biomedcentral.com)
  • The team concluded that the bacterial protein flagellin induces nausea by traveling all the way through the first layer of endothelial cells in the gut to enter the body's inner domain. (science-bbs.com)
  • Flagellin engagement induces dimerization and intracellular signaling via MyD88. (rndsystems.com)
  • Flagellin is the principal component of bacterial flagella, and is present in large amounts on nearly all flagellated bacteria. (wikipedia.org)
  • Some bacteria are able to switch between multiple flagellin genes in order to evade this response. (wikipedia.org)
  • The propensity of the immune response to flagellin may be explained by two facts: Flagellin is an extremely abundant protein in flagellated bacteria. (wikipedia.org)
  • In addition, as the structural component of flagella, elevated levels of flagellin might reflect enriched levels of motile bacteria that have high ability to penetrate the mucus layer that serves to protect the host against microbial onslaught. (nature.com)
  • Hence, we hypothesize that boosting levels of mucosal flagellin-specific IgA might help keep flagellated bacteria in check and, consequently protect against development of chronic gut inflammation. (nature.com)
  • Therefore, T cell reactivities against whole bacteria, recombinant 31-kD (outer surface protein A, [OspA]), and 41-kD proteins (flagellin) from B. burgdorferi were studied in patients with LB, non-LB patients, and healthy donors. (jci.org)
  • Flagellin is the main structural component of flagella, the miniature whips bacteria use to propel themselves. Several Emory scientists are investigating how flagellin could be used as a protective agent to strengthen the body's innate defenses and also as a vaccine component. (emoryhealthsciblog.com)
  • flagellin may act as a basic signal to alert the immune system to the presence of bacteria. (science-bbs.com)
  • Salmonella typhimurium bacteria cause diarrhea using a novel mechanism: the bacterial protein flagellin finds its way through the first layer of the intestinal cells lining the gut, where the body's response mechanisms kicks in to try and rid the foreigner. (science-bbs.com)
  • Many bacteria, including the ubiquitous Escherichia coli and many types of 'good' bacteria, produce and secrete flagellin, a protein that makes up bacterial flagella. (science-bbs.com)
  • As the gut is full of bacteria, intestinal epithelial cells are constantly exposed to flagellin to no ill effect. (science-bbs.com)
  • When they injected flagellin from other bacteria into the far-gut side, IL-8 was secreted. (science-bbs.com)
  • And no one yet knows how this type of salmonella bacteria allows flagellin to break across the barrier when flagellin secreted from other bacteria do not. (science-bbs.com)
  • Since flagellin is conserved in many microorganisms, Galan adds that flagellin may act as a basic signal to alert the immune system to the presence of bacteria. (science-bbs.com)
  • In bacteria the flagella is made of one flagellin tread and it rotates. (bspp.org.uk)
  • Alterations in bacterial species resulted in bacteria expressing more flagellin and lipopolysaccharide, which can activate pro-inflammatory gene expression by the immune system. (eurekalert.org)
  • Here, we set out to investigate whether elicitation of mucosal anti-flagellin antibodies by direct administration of purified flagellin might serve as a general vaccine against subsequent development of chronic gut inflammation. (nature.com)
  • Despite the important role of anti-flagellin antibodies in maintaining the intestinal homeostasis, regulatory mechanisms underlying the flagellin-specific antibody responses are not well understood. (kaist.ac.kr)
  • Thus, administration of flagellin, and perhaps other pathobiont antigens, may confer some protection against chronic inflammatory diseases. (nature.com)
  • However, analyses using the purified antigens OspA and flagellin revealed considerable heterogeneity in the cellular reactivities among individuals as well as variations during the course of infection. (jci.org)
  • These results identify flagellins as a class of immunodominant antigens that stimulate pathogenic intestinal immune reactions in genetically diverse hosts and suggest new avenues for the diagnosis and antigen-directed therapy of patients with IBD. (nih.gov)
  • Serum IgG to these flagellins, but not to the dissimilar Salmonella muenchen flagellin, was elevated in patients with Crohn disease, but not in patients with ulcerative colitis or in controls. (nih.gov)
  • Relationship between genotype and phenotype of flagellin C in Salmonella. (wjgnet.com)
  • Reciprocally, several control subjects demonstrated marked cellular responses to OspA and flagellin, suggesting that reactions to these proteins may not always be related to LB. T cell reactivity did not correlate well with the presence of specific antibodies. (jci.org)
  • Almost all seropositive patients in both early and late stage LB had serum antibodies against flagellin, but antibodies to OspA were detectable only in a subset of late LB sera. (jci.org)
  • Glycan staining of purified flagella and treatment with N-glycosidase F suggested that flagellin of T. thermophilus is a glycosylated protein. (unic.ac.cy)
  • For me, what was most surprising about this paper was that treatment with flagellin, or immune signaling proteins activated by flagellin, can get mice with severely impaired immune systems â€" no T cells or B cells at all - to evict rotavirus. (emoryhealthsciblog.com)
  • Here we report the structure of a bacterial flagellin derivative in complex with the NLR proteins NAIP5 and NLRC4 determined by cryo-electron microscopy at 4.28 Å resolution. (elsevierpure.com)
  • Next, the team tested how their culture system responded to S. typhimurium missing the flagellin gene. (science-bbs.com)
  • Thermus thermophilus HB8 flagellin protein (FliC) is encoded by the TTHC004 (fliC) gene, which is located in the pTT8 plasmid of the bacterium. (unic.ac.cy)
  • Western blot immunodetection with anti-FliC revealed a stable complex (FliC) 1 (FliS) 2 of flagellin (FliC, 27.7 kDa) with a homodimer of FliS (FliS, 18.2 kDa) that are encoded by TTHC004 and TTHC003 genes, respectively. (unic.ac.cy)
  • Additionally three adjuvant combinations were tested: (i) Emulsigen®, (ii) bacterial flagellin (FliC) and (iii) Emulsigen® + bacterial flagellin. (nottingham.ac.uk)
  • It is expressed on mucosal epithelia in the gastrointestinal tract, airways, and other areas of potential bacterial contact and recognizes bacterial flagellin. (rndsystems.com)
  • Yet, like many disease-associated immune responses, adaptive immunity to flagellin likely plays an important role in keeping microbes in check. (nature.com)
  • We show, in mice, that repeated injection of flagellin elicits increases in fecal anti-flagellin IgA and alterations in microbiota composition, reduces fecal flagellin concentration, prevents microbiota encroachment, protects against IL-10 deficiency-induced colitis, and ameliorates diet-induced obesity. (nature.com)
  • Multiple strains of colitic mice had elevated serum anti-flagellin IgG2a responses and Th1 T cell responses to flagellin. (nih.gov)
  • In addition, flagellin-specific CD4(+) T cells induced severe colitis when adoptively transferred into naive SCID mice. (nih.gov)
  • Flagellin can protect against all those things (in mice, of course)? (emoryhealthsciblog.com)
  • The scientists found the flagellin-immunized mice did not experience an invasion of microbes into their gut mucosal lining after consuming the emulsifiers. (medicalnewstoday.com)
  • Additionally, researchers discovered that flagellin immunization appeared to help protect the mice from chronic intestinal inflammation and metabolic dysregulations typically seen after ingesting dietary emulsifiers. (medicalnewstoday.com)
  • In addition, we found that antiflagellin IgG2c and IgA responses were severely impaired in interferon-alpha receptor 1 (IFNAR1)-deficient mice, suggesting that IFN-beta produced by the flagellin stimulation regulates anti-flagellin antibody class switching. (kaist.ac.kr)
  • MATERIALS & METHODS: Mice were treated sublingually with flagellin and challenged intranasally with a lethal dose of pneumococcus. (hal.science)
  • In addition, a 22-amino acid sequence (flg22) of the conserved N-terminal part of flagellin is known to activate plant defence mechanisms. (wikipedia.org)
  • Flagellin can also serve as a specific antigen for the adaptive immune system and stimulate anti-flagellin antibody responses. (kaist.ac.kr)
  • Incubation of NCI-H292 cells with exogenous IL-8 induced MUC5AC expression and pre-incubation of these cells with an anti-IL-8 antibody abrogated flagellin-mediated MUC5AC expression. (pasteur.fr)
  • In accord with the notion that a microbiota expressing high levels of flagellin pose danger to the host, flagellin is also a dominant target of adaptive mucosal immunity, particularly in Crohn's disease 11 . (nature.com)
  • For this study, Dr. Benoit Chassaing , Inserm principal investigator at the Institut Cochin, INSERM &Université Paris Cité, France, and his team decided to train the mucosal immune system against a specific protein called flagellin . (medicalnewstoday.com)
  • Using a mouse model, the researchers trained the mice's mucosal immune system in the gut to target flagellin, granting it immunity from the protein. (medicalnewstoday.com)
  • Our findings shed a new light on the regulation of flagellin-mediated immune activation and may help find new strategies to promote the intestinal health and develop mucosal vaccines. (kaist.ac.kr)
  • Flagellin-stimulated lung epithelial cells recapitulated the lung's transcriptional profile suggesting they could be targeted by flagellin in vivo. (hal.science)
  • Herein, we describe that repeated systemic administration of purified flagellin elicits a robust anti-flagellin fecal IgA response that serves to reshape microbiota composition, reduces flagellin expression, and protects against experimental colitis and metabolic syndrome. (nature.com)
  • Researchers from the Max Planck Institute for Biology Tübingen have identified a new type of flagellin in the human gut, termed 'silent flagellin', that binds to the immune receptor Toll-like receptor 5 without inducing a pro-inflammatory response. (the-microbiologist.com)
  • We complement our study on flagellar abundance with research to understanding how a filament is assembled from multiple flagellins, a trait maintained by many bacterial species. (ncl.ac.uk)
  • The helical N- and C-termini of flagellin form the inner core of the flagellin protein, and is responsible for flagellin's ability to polymerize into a filament. (wikipedia.org)
  • Mutations within one conserved surface identify residues D295 and D367 as important for flagellin recognition. (silverchair.com)
  • While the termini of the protein are quite similar among all bacterial flagellins, the middle portion is wildly variable and can be absent in some species. (wikipedia.org)
  • A significant number of bacterial species encode multiple copies of the filament building block - flagellin. (ncl.ac.uk)
  • Using a mouse model of pulmonary infection we showed that PAK, a wild type strain of P. aeruginosa, induced airway mucus secretion and mucin muc5ac expression at higher levels than its flagellin-deficient mutant (ΔFliC). (pasteur.fr)
  • A purified P. aeruginosa flagellin induced MUC5AC expression in parallel to IL-8 secretion in NCI-H292 cells. (pasteur.fr)
  • Finally, inhibition of ERK abolished the expression of both PAK- and flagellin-induced MUC5AC. (pasteur.fr)
  • Their work addresses the long-standing question of how benign gut microbes evade the immune system and reshapes our understanding of how immune receptors interact with the bacterial motility protein flagellin. (the-microbiologist.com)
  • Flagellin is a globular protein that arranges itself in a hollow cylinder to form the filament in a bacterial flagellum. (wikipedia.org)
  • The structure of flagellin is responsible for the helical shape of the flagellar filament, which is important for its proper function. (wikipedia.org)
  • The filament is made up of eleven smaller "protofilaments", nine of which contains flagellin in the L-type shape and the other two in the R-type shape. (wikipedia.org)
  • Using a Xa pathotype C strain that infects Mexican lime only and sweet oranges as a pathosystem to study the immune response triggered by this bacterium in these hosts, we herein report that the Xa flagellin C protein (XaFliC) acts as a potent defence elicitor in sweet oranges . (bvsalud.org)
  • Flagellin perception in Arabidopsis thaliana functions via the receptor-like-kinase FLS2 (FLAGELLIN SENSING 2). (wikipedia.org)
  • Suppression of citrus canker disease mediated by flagellin perception. (bvsalud.org)
  • Flagellin's impact on the microbiota is B-lymphocyte dependent and, in humans, obese subjects exhibit increased levels of fecal flagellin and reduced levels of fecal flagellin-specific IgA, relative to normal weight subjects. (nature.com)
  • 2021) A complex immune response to flagellin epitope variation in commensal communities. (oeaw.ac.at)
  • Flagellin is a P. aeruginosa virulence factor involved in host response to this pathogen. (pasteur.fr)
  • The middle part of E. coli (and related) flagellin, D3, displays a beta-folium fold and appears to maintain flagellar stability. (wikipedia.org)
  • The extreme C-terminal side of the flagellin is anchored to a sterically constrained binding pocket of NAIP5, which likely acts as a structural determinant for discrimination of different bacterial flagellins by NAIP5, a notion further supported by biochemical data. (elsevierpure.com)
  • The structure revealed that the flagellin derivative forms two parallel helices interacting with multiple domains including BIR1 and LRR of NAIP5. (elsevierpure.com)
  • On Thursday, a team of researchers led by immunologist Andrew Gewirtz reported in Science  that treatment with flagellin can prevent or cure rotavirus infection in animals. (emoryhealthsciblog.com)