Escherichia coli Vaccines
Bacterial Vaccines
Escherichia coli
Vaccines
Escherichia coli O157
Molecular Sequence Data
Vaccines, Inactivated
Base Sequence
Plasmids
Amino Acid Sequence
Escherichia coli K12
Cloning, Molecular
Viral Vaccines
Bioreactors
Bioengineering
Polypropylenes
Spectinomycin
Switzerland
Fermentation
Cholera
Rotavirus
Diarrhea
Rotavirus Infections
Enterotoxigenic Escherichia coli
Cholera Toxin
Intestinal immune responses in patients infected with enterotoxigenic Escherichia coli and in vaccinees. (1/100)
Immune responses against enterotoxigenic Escherichia coli (ETEC) were examined in Bangladeshi adults with naturally acquired disease and compared to responses in age-matched Bangladeshi volunteers who had been orally immunized with a vaccine consisting of inactivated ETEC bacteria expressing different colonization factor antigens (CFs) and the B subunit of cholera toxin. B-cell responses in duodenal biopsy samples, feces, intestinal washings, and blood were determined. Because most of the patients included in the study were infected with ETEC expressing CS5, immune responses to this CF were studied most extensively. Vaccinees and patients had comparable B-cell responses against this antigen in the duodenum: the median numbers of antibody-secreting cells (ASC) were 3,300 immunoglobulin A (IgA) ASC/10(7) mononuclear cells (MNC) in the patient group (n = 8) and 1,200 IgA ASC/10(7) MNC in the vaccinees (n = 13) (not a significant difference). Similarly, no statistically significant differences were seen in the levels of duodenal B cells directed against enterotoxin among vaccinees and patients. A comparison of the capacities of the various methods used to assess mucosal immune responses revealed a correlation between numbers of circulating B cells and antibody levels in saponin extracts of duodenal biopsy samples (r = 0.58; n = 13; P = 0.04) after vaccination. However, no correlation was seen between blood IgA ASC and duodenal IgA ASC after two doses of vaccine. Still, a correlation between numbers of CF-specific B cells in blood sampled from patients early during infection and numbers of duodenal B cells collected 1 week later was apparent (r = 0.70; n = 10; P = 0.03). (+info)Safety and immunogenicity of two different lots of the oral, killed enterotoxigenic escherichia coli-cholera toxin B subunit vaccine in Israeli young adults. (2/100)
Enterotoxigenic Escherichia coli (ETEC) is one of the leading causes of diarrhea among Israeli soldiers serving in field units. Two double-blind placebo-controlled, randomized trials were performed among 155 healthy volunteers to evaluate the safety and immunogenicity of different lots of the oral, killed ETEC vaccine consisting of two doses of whole cells plus recombinantly produced cholera toxin B subunit (rCTB). The two doses of vaccine lot E005 and the first dose of vaccine lot E003 were well tolerated by the volunteers. However, 5 (17%) vaccinees reported an episode of vomiting a few hours after the second dose of lot E003; none of the placebo recipients reported similar symptoms. Both lots of vaccine stimulated a rate of significant antibody-secreting cell (ASC) response to CTB and to colonization factor antigen I (CFA/I) after one or two doses, ranging from 85 to 100% and from 81 to 100%, respectively. The rate of ASC response to CS2, CS4, and CS5 was slightly lower than the rate of ASC response induced to CTB, CFA/I, and CS1. The second vaccine dose enhanced the response to CTB but did not increase the frequencies or magnitude of ASC responses to the other antigens. The two lots of the ETEC vaccine induced similar rates of serum antibody responses to CTB and CFA/I which were less frequent than the ASC responses to the same antigens. Based on these safety and immunogenicity data, an efficacy study of the ETEC vaccine is under way in the Israel Defense Force. (+info)Molecular variation among type IV pilin (bfpA) genes from diverse enteropathogenic Escherichia coli strains. (3/100)
Typical enteropathogenic Escherichia coli (EPEC) strains produce bundle-forming pili (BFP), type IVB fimbriae that have been implicated in EPEC virulence, antigenicity, autoaggregation, and localized adherence to epithelial cells (LA). BFP are polymers of bundlin, a pilin protein that is encoded by the bfpA gene found on a large EPEC plasmid. Striking sequence variation has previously been observed among type IV pilin genes of other gram-negative bacterial pathogens (e.g., Pseudomonas and Neisseria spp.). In contrast, the established sequences of bfpA genes from two distantly related prototype EPEC strains vary by only a single base pair. To determine whether bundlin sequences vary more extensively, we used PCR to amplify the bfpA genes from 19 EPEC strains chosen for their various serotypes and sites and years of isolation. Eight different bfpA alleles were identified by sequencing of the PCR products. These alleles can be classified into two major groups. The alpha group contains three alleles derived from strains carrying O55, O86, O111, O119, O127, or O128 somatic antigens. The beta group contains five alleles derived from strains carrying O55, O110, O128ab, O142, or nontypeable antigens. Sequence comparisons show that bundlin has highly conserved and variable regions, with most of the variation occurring in the C-terminal two-thirds of the protein. The results of multilocus enzyme electrophoresis support the hypothesis that bfpA sequences have spread horizontally across distantly related clonal lineages. Strains with divergent bundlin sequences express bundlin protein, produce BFP, and carry out autoaggregation and LA. However, four strains lack most or all of these phenotypes despite having an intact bfpA gene. These results have important implications for our understanding of bundlin structure, transmission of the bfp gene cluster among EPEC strains, and the role of bundlin variation in the evasion of host immune system responses. (+info)Immunoprophylactic potential of cloned Shiga toxin 2 B subunit. (4/100)
The Shiga toxins Stx1 and Stx2 contribute to the development of enterohemorrhagic O157:H7 Escherichia coli-mediated colitis and hemolytic-uremic syndrome in humans. The Stx2 B subunit, which binds to globotriaosylceramide (GB3) receptors on target cells, was cloned. This involved replacing the Stx2 B subunit leader peptide nucleotide sequences with those from the Stx1 B subunit. The construct was expressed in the TOPP3 E. coli strain. The Stx2 B subunits from this strain assembled into a pentamer and bound to a GB3 receptor analogue. The cloned Stx2 B subunit was not cytotoxic to Vero cells or apoptogenic in Burkitt's lymphoma cells. Although their immune response to the Stx2 B subunit was variable, rabbits that developed Stx2 B subunit-specific antibodies, as determined by immunoblot and in vitro cytotoxicity neutralization assays, survived a challenge with Stx2 holotoxin. This is thought to be the first demonstration of the immunoprophylactic potential of the Stx2 B subunit. (+info)Oral administration of formaldehyde-killed recombinant bacteria expressing a mimic of the Shiga toxin receptor protects mice from fatal challenge with Shiga-toxigenic Escherichia coli. (5/100)
Gastrointestinal disease caused by Shiga toxin-producing Escherichia coli (STEC) is frequently complicated by life-threatening toxin-induced systemic sequelae, including the hemolytic uremic syndrome. We previously constructed a recombinant bacterium displaying a Shiga toxin receptor mimic on its surface which neutralized Shiga toxins with very high efficiency. Moreover, oral administration of the live bacterium completely protected mice from challenge with virulent STEC. In this study, we investigated the protective capacity of formaldehyde-killed receptor mimic bacteria, as these are likely to be safer for administration to humans. The killed bacteria completely protected STEC-challenged mice when administered three times daily; incomplete protection was achieved using two doses per day. Commencement of therapy could be delayed for up to 48 h after challenge without diminishing protection, depending on the virulence of the challenge strain. Thus, administration of this agent early in the course of human STEC disease may prevent progression to life-threatening complications. (+info)Active immunization with a detoxified Escherichia coli J5 lipopolysaccharide group B meningococcal outer membrane protein complex vaccine protects animals from experimental sepsis. (6/100)
The passive infusion of antibodies elicited in rabbits with a detoxified J5 lipopolysaccharide (LPS)/group B meningococcal outer membrane protein complex vaccine protected neutropenic rats from heterologous lethal gram-negative bacterial infection. In this study, active immunization was studied in neutropenic rats infected with Pseudomonas aeruginosa, in the presence or absence of ceftazidime therapy, and with Klebsiella pneumoniae. This vaccine elicited a > 200-fold increase in anti-J5 LPS antibody, which remained elevated throughout the duration of cyclophosphamide-induced neutropenia and for < or = 3 months. There was improved survival among immunized versus control animals: 48% (13/28) versus 7% (2/29) in Pseudomonas-challenged rats; 61% (11/18) versus 0% (0/10) in Pseudomonas- and ceftazidime-treated rats; and 64% (9/14) versus 13% (2/15) in Klebsiella-challenged rats (P < 0.01 for each comparison). Immunized animals had lower levels of bacteria in organs and lower levels of circulating endotoxin at the onset of fever. In conclusion, active immunization with an anti-endotoxin vaccine improved survival after infection with > or = 2 heterologous, clinically relevant bacterial species in immunocompromised animals. Active immunization with this vaccine merits further investigation. (+info)Dose-dependent circulating immunoglobulin A antibody-secreting cell and serum antibody responses in Swedish volunteers to an oral inactivated enterotoxigenic Escherichia coli vaccine. (7/100)
The immunogenicity of different preparations of an oral inactivated enterotoxigenic Escherichia coli (ETEC) vaccine was evaluated in Swedish volunteers previously unexposed to ETEC infection. The vaccine preparations consisted of recombinant cholera toxin B subunit (CTB) and various amounts of formalin-killed whole bacteria expressing the most prevalent colonization factor antigens (CFAs). Significant immunoglobulin A (IgA) antibody-secreting cell (ASC) responses against CTB and the various CFA components were seen in a majority of volunteers after two doses of ETEC vaccine independent of the vaccine lot given. The IgA ASC responses against CTB were significantly higher after the second than after the first immunization, whereas the CFA-specific IgA ASC responses were almost comparable after the first and second doses of ETEC vaccine. Two immunizations with one-third of a full dose of CFA-ETEC bacteria induced lower frequencies of IgA ASC responses against all the different CFAs than two full vaccine doses, i.e., 63 versus 80% for CFA/I, 56 versus 70% for CS1, 31 versus 65% for CS2, and 56 versus 75% for CS4. The proportion of vaccinees responding with rises in the titer of serum IgA antibody against the various CFA antigens was also lower after immunization with the reduced dose of CFA-ETEC bacteria. These findings suggest that measurements of circulating IgA ASCs can be used not only for qualitative but also for quantitative assessments of the immunogenicity of individual fimbrial antigens in various preparations of ETEC vaccine. (+info)Construction and characterization of genetically defined aro omp mutants of enterotoxigenic Escherichia coli and preliminary studies of safety and immunogenicity in humans. (8/100)
Enterotoxigenic Escherichia coli (ETEC) is a leading cause of diarrhea in travelers to countries where the disease is endemic and causes a major disease burden in the indigenous population, particularly children. We describe here the generation and preclinical characterization of candidate strains of ETEC which are intended to provide the basis of a live attenuated oral vaccine to prevent this disease. It has been shown previously that a spontaneously arising toxin-negative variant ETEC strain, E1392/75-2A, could confer 75% protection against challenge when administered to volunteers. Unfortunately this strain induced mild diarrhea in 15% of recipients. To eliminate the unacceptable reactogenicity of strain E1392/75-2A, it was further attenuated by introducing three different combinations of defined deletion mutations into the chromosome. A mouse intranasal model of immunization was developed and used to show that all of the strains were immunogenic. Immune responses against colonization factor antigens (CFAs) were particularly strong when the bacterial inocula were grown on "CFA agar," which induces strong expression of these antigens. Two of the strains were selected for a phase I dose escalation safety study with healthy adult volunteers. Freshly grown organisms were harvested from CFA agar plates and administered to volunteers as a suspension containing from 5 x 10(7) to 5 x 10(9) CFU. The vaccine was well tolerated at all doses and induced significant immune responses in all recipients at the highest dose of either strain. The results provide the basis for further clinical evaluation of these vaccine candidates. (+info)Escherichia coli (E. coli) vaccines are designed to protect against infections caused by various strains of the E. coli bacterium. These vaccines typically contain inactivated or attenuated (weakened) forms of the bacteria, which stimulate an immune response when introduced into the body. The immune system learns to recognize and fight off the specific strain of E. coli used in the vaccine, providing protection against future infections with that strain.
There are several types of E. coli vaccines available or in development, including:
1. Shiga toxin-producing E. coli (STEC) vaccines: These vaccines protect against STEC strains, such as O157:H7 and non-O157 STECs, which can cause severe illness, including hemorrhagic colitis and hemolytic uremic syndrome (HUS).
2. Enterotoxigenic E. coli (ETEC) vaccines: These vaccines target ETEC strains that are a common cause of traveler's diarrhea in people visiting areas with poor sanitation.
3. Enteropathogenic E. coli (EPEC) vaccines: EPEC strains can cause persistent diarrhea, especially in young children in developing countries. Vaccines against these strains are still in the research and development stage.
4. Extraintestinal pathogenic E. coli (ExPEC) vaccines: These vaccines aim to protect against ExPEC strains that can cause urinary tract infections, sepsis, and meningitis.
It is important to note that different E. coli vaccines are designed for specific purposes and may not provide cross-protection against other strains or types of E. coli infections.
Escherichia coli (E. coli) infections refer to illnesses caused by the bacterium E. coli, which can cause a range of symptoms depending on the specific strain and site of infection. The majority of E. coli strains are harmless and live in the intestines of healthy humans and animals. However, some strains, particularly those that produce Shiga toxins, can cause severe illness.
E. coli infections can occur through various routes, including contaminated food or water, person-to-person contact, or direct contact with animals or their environments. Common symptoms of E. coli infections include diarrhea (often bloody), abdominal cramps, nausea, and vomiting. In severe cases, complications such as hemolytic uremic syndrome (HUS) can occur, which may lead to kidney failure and other long-term health problems.
Preventing E. coli infections involves practicing good hygiene, cooking meats thoroughly, avoiding cross-contamination of food during preparation, washing fruits and vegetables before eating, and avoiding unpasteurized dairy products and juices. Prompt medical attention is necessary if symptoms of an E. coli infection are suspected to prevent potential complications.
Bacterial vaccines are types of vaccines that are created using bacteria or parts of bacteria as the immunogen, which is the substance that triggers an immune response in the body. The purpose of a bacterial vaccine is to stimulate the immune system to develop protection against specific bacterial infections.
There are several types of bacterial vaccines, including:
1. Inactivated or killed whole-cell vaccines: These vaccines contain entire bacteria that have been killed or inactivated through various methods, such as heat or chemicals. The bacteria can no longer cause disease, but they still retain the ability to stimulate an immune response.
2. Subunit, protein, or polysaccharide vaccines: These vaccines use specific components of the bacterium, such as proteins or polysaccharides, that are known to trigger an immune response. By using only these components, the vaccine can avoid using the entire bacterium, which may reduce the risk of adverse reactions.
3. Live attenuated vaccines: These vaccines contain live bacteria that have been weakened or attenuated so that they cannot cause disease but still retain the ability to stimulate an immune response. This type of vaccine can provide long-lasting immunity, but it may not be suitable for people with weakened immune systems.
Bacterial vaccines are essential tools in preventing and controlling bacterial infections, reducing the burden of diseases such as tuberculosis, pneumococcal disease, meningococcal disease, and Haemophilus influenzae type b (Hib) disease. They work by exposing the immune system to a harmless form of the bacteria or its components, which triggers the production of antibodies and memory cells that can recognize and fight off future infections with that same bacterium.
It's important to note that while vaccines are generally safe and effective, they may cause mild side effects such as pain, redness, or swelling at the injection site, fever, or fatigue. Serious side effects are rare but can occur, so it's essential to consult with a healthcare provider before receiving any vaccine.
'Escherichia coli (E. coli) proteins' refer to the various types of proteins that are produced and expressed by the bacterium Escherichia coli. These proteins play a critical role in the growth, development, and survival of the organism. They are involved in various cellular processes such as metabolism, DNA replication, transcription, translation, repair, and regulation.
E. coli is a gram-negative, facultative anaerobe that is commonly found in the intestines of warm-blooded organisms. It is widely used as a model organism in scientific research due to its well-studied genetics, rapid growth, and ability to be easily manipulated in the laboratory. As a result, many E. coli proteins have been identified, characterized, and studied in great detail.
Some examples of E. coli proteins include enzymes involved in carbohydrate metabolism such as lactase, sucrase, and maltose; proteins involved in DNA replication such as the polymerases, single-stranded binding proteins, and helicases; proteins involved in transcription such as RNA polymerase and sigma factors; proteins involved in translation such as ribosomal proteins, tRNAs, and aminoacyl-tRNA synthetases; and regulatory proteins such as global regulators, two-component systems, and transcription factors.
Understanding the structure, function, and regulation of E. coli proteins is essential for understanding the basic biology of this important organism, as well as for developing new strategies for combating bacterial infections and improving industrial processes involving bacteria.
'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.
While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.
E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.
A vaccine is a biological preparation that provides active acquired immunity to a particular infectious disease. It typically contains an agent that resembles the disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it, and "remember" it, so that the immune system can more easily recognize and destroy any of these microorganisms that it encounters in the future.
Vaccines can be prophylactic (to prevent or ameliorate the effects of a future infection by a natural or "wild" pathogen), or therapeutic (to fight disease that is already present). The administration of vaccines is called vaccination. Vaccinations are generally administered through needle injections, but can also be administered by mouth or sprayed into the nose.
The term "vaccine" comes from Edward Jenner's 1796 use of cowpox to create immunity to smallpox. The first successful vaccine was developed in 1796 by Edward Jenner, who showed that milkmaids who had contracted cowpox did not get smallpox. He reasoned that exposure to cowpox protected against smallpox and tested his theory by injecting a boy with pus from a cowpox sore and then exposing him to smallpox, which the boy did not contract. The word "vaccine" is derived from Variolae vaccinae (smallpox of the cow), the term devised by Jenner to denote cowpox. He used it in 1798 during a conversation with a fellow physician and later in the title of his 1801 Inquiry.
Escherichia coli (E. coli) O157 is a serotype of the bacterium E. coli that is associated with foodborne illness. This strain is pathogenic and produces Shiga toxins, which can cause severe damage to the lining of the small intestine and potentially lead to hemorrhagic diarrhea and kidney failure. E. coli O157 is often transmitted through contaminated food, particularly undercooked ground beef, as well as raw or unpasteurized dairy products, fruits, and vegetables. It can also be spread through contact with infected individuals or animals, especially in settings like farms, petting zoos, and swimming pools. Proper food handling, cooking, and hygiene practices are crucial to preventing E. coli O157 infections.
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.
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.
Inactivated vaccines, also known as killed or non-live vaccines, are created by using a version of the virus or bacteria that has been grown in a laboratory and then killed or inactivated with chemicals, heat, or radiation. This process renders the organism unable to cause disease, but still capable of stimulating an immune response when introduced into the body.
Inactivated vaccines are generally considered safer than live attenuated vaccines since they cannot revert back to a virulent form and cause illness. However, they may require multiple doses or booster shots to maintain immunity because the immune response generated by inactivated vaccines is not as robust as that produced by live vaccines. Examples of inactivated vaccines include those for hepatitis A, rabies, and influenza (inactivated flu vaccine).
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.
A plasmid is a small, circular, double-stranded DNA molecule that is separate from the chromosomal DNA of a bacterium or other organism. Plasmids are typically not essential for the survival of the organism, but they can confer beneficial traits such as antibiotic resistance or the ability to degrade certain types of pollutants.
Plasmids are capable of replicating independently of the chromosomal DNA and can be transferred between bacteria through a process called conjugation. They often contain genes that provide resistance to antibiotics, heavy metals, and other environmental stressors. Plasmids have also been engineered for use in molecular biology as cloning vectors, allowing scientists to replicate and manipulate specific DNA sequences.
Plasmids are important tools in genetic engineering and biotechnology because they can be easily manipulated and transferred between organisms. They have been used to produce vaccines, diagnostic tests, and genetically modified organisms (GMOs) for various applications, including agriculture, medicine, and industry.
Bacterial DNA refers to the genetic material found in bacteria. It is composed of a double-stranded helix containing four nucleotide bases - adenine (A), thymine (T), guanine (G), and cytosine (C) - that are linked together by phosphodiester bonds. The sequence of these bases in the DNA molecule carries the genetic information necessary for the growth, development, and reproduction of bacteria.
Bacterial DNA is circular in most bacterial species, although some have linear chromosomes. In addition to the main chromosome, many bacteria also contain small circular pieces of DNA called plasmids that can carry additional genes and provide resistance to antibiotics or other environmental stressors.
Unlike eukaryotic cells, which have their DNA enclosed within a nucleus, bacterial DNA is present in the cytoplasm of the cell, where it is in direct contact with the cell's metabolic machinery. This allows for rapid gene expression and regulation in response to changing environmental conditions.
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.
Escherichia coli (E. coli) K12 is a strain of the bacterium E. coli that is commonly used in scientific research. It was originally isolated from the human intestine and has been well-studied due to its relatively harmless nature compared to other strains of E. coli that can cause serious illness.
The "K12" designation refers to a specific set of genetic characteristics that distinguish this strain from others. It is a non-pathogenic, or non-harmful, strain that is often used as a model organism in molecular biology and genetics research. Researchers have developed many tools and resources for studying E. coli K12, including a complete genome sequence and extensive collections of mutant strains.
E. coli K12 is not typically found in the environment and is not associated with disease in healthy individuals. However, it can be used as an indicator organism to detect fecal contamination in water supplies, since it is commonly present in the intestines of warm-blooded animals.
Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:
1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.
Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.
A viral vaccine is a biological preparation that introduces your body to a specific virus in a way that helps your immune system build up protection against the virus without causing the illness. Viral vaccines can be made from weakened or inactivated forms of the virus, or parts of the virus such as proteins or sugars. Once introduced to the body, the immune system recognizes the virus as foreign and produces an immune response, including the production of antibodies. These antibodies remain in the body and provide immunity against future infection with that specific virus.
Viral vaccines are important tools for preventing infectious diseases caused by viruses, such as influenza, measles, mumps, rubella, polio, hepatitis A and B, rabies, rotavirus, chickenpox, shingles, and some types of cancer. Vaccination programs have led to the control or elimination of many infectious diseases that were once common.
It's important to note that viral vaccines are not effective against bacterial infections, and separate vaccines must be developed for each type of virus. Additionally, because viruses can mutate over time, it is necessary to update some viral vaccines periodically to ensure continued protection.
A bioreactor is a device or system that supports and controls the conditions necessary for biological organisms, cells, or tissues to grow and perform their specific functions. It provides a controlled environment with appropriate temperature, pH, nutrients, and other factors required for the desired biological process to occur. Bioreactors are widely used in various fields such as biotechnology, pharmaceuticals, agriculture, and environmental science for applications like production of therapeutic proteins, vaccines, biofuels, enzymes, and wastewater treatment.
Antifoaming agents are substances that prevent or reduce the formation of foam in liquids. They are often used in industrial processes, such as manufacturing and food production, to minimize the negative effects of foam on equipment performance, product quality, and safety. In a medical context, antifoaming agents may be used in certain medications, intravenous (IV) fluids, or enteral feedings to prevent or treat foaming that can interfere with proper administration or absorption of the treatment.
These agents work by reducing surface tension, promoting bubble rupture, or absorbing excess gases. Common antifoaming agents include silicone-based compounds, such as dimethicone and simethicone, as well as other substances like polyoxyethylene sorbitan monostearate (Tween) and alcohols.
In some cases, antifoaming agents may be used during medical procedures to prevent or treat the accumulation of foam in body cavities, such as the stomach or lungs. For instance, simethicone is sometimes administered to newborns with meconium ileus (a bowel obstruction caused by thickened meconium) to help reduce the formation of gas and facilitate the passage of meconium. Similarly, antifoaming agents may be used in mechanical ventilation to prevent or treat pulmonary air leaks and improve oxygenation.
While antifoaming agents are generally considered safe when used as directed, they can have side effects, particularly if overused or misused. Potential adverse reactions include gastrointestinal symptoms like diarrhea, nausea, or bloating, as well as allergic reactions in sensitive individuals. It is essential to follow the recommended dosage and administration guidelines provided by a healthcare professional when using antifoaming agents for medical purposes.
Bioengineering, also known as biological engineering, is defined as the application of principles and methods from engineering to study, modify, and control biological systems, often with the goal of creating new technologies or improving existing ones. This field combines knowledge and expertise from various disciplines, including biology, chemistry, physics, mathematics, and computer science, to solve complex problems related to health, medicine, agriculture, and the environment.
Bioengineers may work on a wide range of projects, such as developing new medical devices or therapies, designing synthetic biological systems for industrial applications, creating biosensors for environmental monitoring, or engineering tissues and organs for transplantation. They use a variety of tools and techniques, including genetic engineering, biomaterials, computational modeling, and nanotechnology, to design and build novel biological systems that can perform specific functions or solve practical problems.
Bioengineering has the potential to transform many areas of science and technology, with significant implications for human health, sustainability, and innovation. As such, it is an exciting and rapidly growing field that offers many opportunities for interdisciplinary collaboration and discovery.
I'm sorry for any confusion, but "Polypropylenes" does not have a medical definition as it is not a medical term. Polypropylene is a type of plastic that is used in various medical and non-medical applications. It is a thermoplastic polymer resin that is produced by the polymerization of propylene.
In the medical field, polypropylene is sometimes used to make single-use surgical instruments, sutures, and medical devices due to its resistance to heat, chemicals, and electricity. It is also biocompatible, meaning it can be safely used in the body without causing adverse reactions. However, "Polypropylenes" as a medical term is not recognized or used in the medical community.
Spectinomycin is an antibiotic that belongs to the aminoglycoside family. It works by binding to the 30S subunit of the bacterial ribosome, thereby inhibiting protein synthesis and leading to bacterial cell death. Spectinomycin is primarily used to treat infections caused by susceptible strains of Gram-negative and Gram-positive bacteria, including gonorrhea, penicillin-resistant streptococci, and some anaerobes. It is administered parenterally (usually intramuscularly) and has a relatively narrow spectrum of activity compared to other aminoglycosides. Spectinomycin is not commonly used in many countries due to the availability of alternative antibiotics with broader spectra and fewer side effects.
I'm sorry for any confusion, but "Switzerland" is not a medical term or concept. Switzerland is a country in Europe, known officially as the Swiss Confederation. If you have any questions about medical terminology or concepts, I'd be happy to try and help answer those for you!
Fermentation is a metabolic process in which an organism converts carbohydrates into alcohol or organic acids using enzymes. In the absence of oxygen, certain bacteria, yeasts, and fungi convert sugars into carbon dioxide, hydrogen, and various end products, such as alcohol, lactic acid, or acetic acid. This process is commonly used in food production, such as in making bread, wine, and beer, as well as in industrial applications for the production of biofuels and chemicals.
Cholera is an infectious disease caused by the bacterium Vibrio cholerae, which is usually transmitted through contaminated food or water. The main symptoms of cholera are profuse watery diarrhea, vomiting, and dehydration, which can lead to electrolyte imbalances, shock, and even death if left untreated. Cholera remains a significant public health concern in many parts of the world, particularly in areas with poor sanitation and hygiene. The disease is preventable through proper food handling, safe water supplies, and improved sanitation, as well as vaccination for those at high risk.
Rotavirus is a genus of double-stranded RNA virus in the Reoviridae family, which is a leading cause of severe diarrhea and gastroenteritis in young children and infants worldwide. The virus infects and damages the cells lining the small intestine, resulting in symptoms such as vomiting, watery diarrhea, abdominal cramps, and fever.
Rotavirus is highly contagious and can be spread through contact with infected individuals or contaminated surfaces, food, or water. The virus is typically transmitted via the fecal-oral route, meaning that it enters the body through the mouth after coming into contact with contaminated hands, objects, or food.
Rotavirus infections are often self-limiting and resolve within a few days to a week, but severe cases can lead to dehydration, hospitalization, and even death, particularly in developing countries where access to medical care and rehydration therapy may be limited. Fortunately, there are effective vaccines available that can prevent rotavirus infection and reduce the severity of symptoms in those who do become infected.
Diarrhea is a condition in which an individual experiences loose, watery stools frequently, often exceeding three times a day. It can be acute, lasting for several days, or chronic, persisting for weeks or even months. Diarrhea can result from various factors, including viral, bacterial, or parasitic infections, food intolerances, medications, and underlying medical conditions such as inflammatory bowel disease or irritable bowel syndrome. Dehydration is a potential complication of diarrhea, particularly in severe cases or in vulnerable populations like young children and the elderly.
According to the World Health Organization (WHO), Rotavirus is the most common cause of severe diarrhea among children under 5 years of age. It is responsible for around 215,000 deaths among children in this age group each year.
Rotavirus infection causes inflammation of the stomach and intestines, resulting in symptoms such as vomiting, watery diarrhea, and fever. The virus is transmitted through the fecal-oral route, often through contaminated hands, food, or water. It can also be spread through respiratory droplets when an infected person coughs or sneezes.
Rotavirus infections are highly contagious and can spread rapidly in communities, particularly in settings where children are in close contact with each other, such as child care centers and schools. The infection is usually self-limiting and resolves within a few days, but severe cases can lead to dehydration and require hospitalization.
Prevention measures include good hygiene practices, such as handwashing with soap and water, safe disposal of feces, and rotavirus vaccination. The WHO recommends the inclusion of rotavirus vaccines in national immunization programs to reduce the burden of severe diarrhea caused by rotavirus infection.
Rotavirus vaccines are preventive measures used to protect against rotavirus infections, which are the leading cause of severe diarrhea and dehydration among infants and young children worldwide. These vaccines contain weakened or inactivated forms of the rotavirus, a pathogen that infects and causes symptoms by multiplying inside cells lining the small intestine.
The weakened or inactivated virus in the vaccine stimulates an immune response in the body, enabling it to recognize and fight off future rotavirus infections more effectively. The vaccines are usually administered orally, as a liquid droplet or on a sugar cube, to mimic natural infection through the gastrointestinal tract.
There are currently two licensed rotavirus vaccines available globally:
1. Rotarix (GlaxoSmithKline): This vaccine contains an attenuated (weakened) strain of human rotavirus and is given in a two-dose series, typically at 2 and 4 months of age.
2. RotaTeq (Merck): This vaccine contains five reassortant viruses, combining human and animal strains to provide broader protection. It is administered in a three-dose series, usually at 2, 4, and 6 months of age.
Rotavirus vaccines have been shown to significantly reduce the incidence of severe rotavirus gastroenteritis and related hospitalizations among infants and young children. The World Health Organization (WHO) recommends the inclusion of rotavirus vaccination in national immunization programs, particularly in countries with high child mortality rates due to diarrheal diseases.
Enterotoxigenic Escherichia coli (ETEC) is a type of diarrheagenic E. coli that causes traveler's diarrhea and diarrheal diseases in infants in developing countries. It produces one or two enterotoxins, known as heat-labile toxin (LT) and heat-stable toxin (ST), which cause the intestinal lining to secrete large amounts of water and electrolytes, resulting in watery diarrhea. ETEC is often transmitted through contaminated food or water and is a common cause of traveler's diarrhea in people traveling to areas with poor sanitation. It can also cause outbreaks in refugee camps, nursing homes, and other institutional settings. Prevention measures include avoiding consumption of untreated water and raw or undercooked foods, as well as practicing good personal hygiene.
Cholera toxin is a protein toxin produced by the bacterium Vibrio cholerae, which causes the infectious disease cholera. The toxin is composed of two subunits, A and B, and its primary mechanism of action is to alter the normal function of cells in the small intestine.
The B subunit of the toxin binds to ganglioside receptors on the surface of intestinal epithelial cells, allowing the A subunit to enter the cell. Once inside, the A subunit activates a signaling pathway that results in the excessive secretion of chloride ions and water into the intestinal lumen, leading to profuse, watery diarrhea, dehydration, and other symptoms associated with cholera.
Cholera toxin is also used as a research tool in molecular biology and immunology due to its ability to modulate cell signaling pathways. It has been used to study the mechanisms of signal transduction, protein trafficking, and immune responses.