The DNA found in parents and offspring after binary fission or budding is exactly the same. Therefore, bacterial cells introduce variation into their genetic material by integrating additional DNA, often from their surroundings, into their genome. This is known as horizontal gene transfer; the resulting genetic variation ensures that bacteria can adapt and survive as their environment changes. [Watch Strange, Glowing Bacteria Harpoon and Swallow DNA to Evolve]Pasteurization: A process by which bacteria in food are killed by heating the food to a particular temperature for some given period of time. Bacteria (singular: bacterium) are a major group of living organisms. The term bacteria (singular: bacterium) has variously applied to all prokaryotes or to a major group of them, otherwise called the eubacteria, depending on ideas about their relationships Is Synthia the synthetic bacterium connected to spikes in recent flesh-eating bacteria?What is Synthia?Something from a mad science fiction novel
A number of factors influence the rate at which bacterial growth occurs, the most important of which are moisture, temperature, and pH. Bacteria Some bacteria also fight off harmful bacteria, helping to prevent illness. Bacteria are also used to help clean up oil spills, keep sewage systems under control, and many other applications
Oral Bacteria Bacteria in the mouth is largely as a result of what we eat (or rather, what we eat and Bad oral bacteria commonly comes in the form of Streptococcus mutans, Porphyromonas gingivalis.. Among the neurological diseases are meningitis, an inflammation of the brain’s membranes caused by Neisseria meningitidis and Hemophilus influenzae. Protein analysis compares the similarity or extent of differences between the entire set of protein products of each bacterium. Using a technique called electrophoresis, the entire set of proteins of each bacterium is separated according to size by an electrical charge applied across gel. The patterns produced when the gel is stained to show the separate bands of proteins reflects the genetic makeup, and relatedness, of the bacteria.In addition to water and the correct salt balance, bacteria also require a wide variety of elements, especially carbon, hydrogen, and nitrogen, sulfur and phosphorus, potassium, iron, magnesium, and calcium. Growth factors, such as vitamins and pyrimi-dines and purines (the building blocks of DNA), are also necessary.
. These endo-spores can survive extreme temperatures, dryness, and exposure to many toxic chemicals and to radiation. Endospores can remain dormant for long periods (hundreds of years in some cases) before being reactivated by the return of favorable conditions.Certain kinds of bacteria are also essential in the decay and decomposition of waste materials. Such bacteria are known as decomposers. Decomposers attack dead materials and break them down into simpler forms that can be used as nutrients by plants.Bacteria, singular bacterium, any of a group of microscopic single-celled organisms that live in enormous numbers in almost every environment on Earth, from deep-sea vents to deep below Earth’s surface to the digestive tracts of humans.Two other kinds of projections found on bacterial surfaces include fimbriae and pili. Fimbriae (pronounced FIM-bree-ay) are tiny bristles that allow bacteria to attach themselves to other objects or to surfaces.
Bacteria are mostly unicellular (single-celled) organisms that lack chlorophyll and are among the smallest living things on Earth—only viruses are smaller. Multiplying rapidly under favorable conditions, bacteria can aggregate into colonies of millions or even billions of organisms within a space as small as a drop of water.The identification schemes of Bergey’s Manual are based on morphology (e.g., coccus, bacillus), staining (gram-positive or negative), cell wall composition (e.g., presence or absence of peptidoglycan), oxygen requirements (e.g., aerobic, facultatively anaerobic) and biochemical tests (e.g., which sugars are aerobically metabolized or fermented).Antibiotic resistance can develop swiftly. For example, resistance to penicillin (the first antibiotic discovered) was recognized almost immediately after introduction of the drug. As of the mid-1990s, almost 80% of all strains of Staphylococcus aureus were resistant to penicillin. Meanwhile, other bacteria remain susceptible to penicillin. An example is provided by Group A Streptococcus pyogenes, another gram-positive bacteria.Stationary phase— Stage of bacterial growth in which the growth rate slows and the production of new cells equals the rate of cell death.
American Society for Microbiology. 1752 N Street NW, Washington, DC 20036. (202) 737-3600. 〈http://www.asmusa.org〉.. Exotoxins are proteins produced during bacterial growth and metabolism and released into the environment. Most of these toxin-producing bacteria are gram positive.Antibiotics— Chemicals produced by microorganisms that inhibit bacterial growth or kill bacterial cells.Bacteria take in nitrogen and release it for plant use when they die. Plants need nitrogen in the soil to live, but they cannot do this themselves. To ensure this, many plant seeds have a small container of bacteria that is used when the plant sprouts.Other proteinaceous projections, called pili, occur singly or in pairs, and join pairs of bacteria together, facilitating transfer of DNA between them.
development and use of antibiotics in the 1940s, most known bacterial diseases have developed a resistance to at least one type of antibiotic..Bacterial cells are generally surrounded by two protective coverings: an outer cell wall and an inner cell membrane. Certain bacteria, like the mycoplasmas, do not have a cell wall at all. Some bacteria may even have a third, outermost protective layer called the capsule. Whip-like extensions often cover the surfaces of bacteria — long ones called flagella or short ones called pili — that help bacteria to move around and attach to a host.“Even if new medicines are developed, without behaviour change, antibiotic resistance will remain a major threat.”
Ribosomes are the sites of protein synthesis. In addition to this DNA, they have an extra circular DNA called plasmid. These plasmids make some strains of bacteria resistant to antibiotics.The evolutionary relatedness of different species can also be determined by laboratory analysis. For example, analysis of the amino acid sequences of proteins from different bacteria disclose how similar the proteins are. In turn, this reflects the similarity of the genes coding for these proteins.
Fermenting bacteria have characteristic sugar fermentation patterns, i.e., they can metabolize some sugars but not others. For example, Neisseria meningitidis ferments glucose and maltose, but not sucrose and lactose, while Neisseria gonorrhoea ferments glucose, but not maltose, sucrose or lactose. Such fermentation patterns can be used to identify and classify bacteria. Intracellular Bacteria Chlamydia Rickettsia Borellia. Gram positive bacteria have a large peptidoglycan structure. As noted above, this accounts for the differential staining with Gram stain
The human intestinal flora, or gut microbiome, contains beneficial mesophilic bacteria, such as dietary Lactobacillus acidophilus. Biofilm bacteria are densely packed communities of microbial cells that grow on living or inert surfaces and surround themselves with secreted polymers. Many bacterial species form biofilms, and their..
The shape of bacterial cells are classified as spherical (coccus), rodlike (bacillus), spiral (spirochete), helical (spirilla) and comma-shaped (vibrio) cells. Many bacilli and vibrio bacteria have whiplike appendages (called flagella ) protruding from the cell surface. Flagella are composed of tight, helical rotors made of chains of globular protein called flagellin, and act as tiny propellers, making the bacteria very mobile.In 2001, Joshua Lederburg coined the term “gut microbiome,” and scientists worldwide are currently seeking to describe and understand more precisely the structures, types, and uses of “gut flora,” or bacteria in the human body.
If the human body is exposed to bacteria that the body does not recognize as helpful, the immune system will attack them. This reaction can lead to the symptoms of swelling and inflammation that we see, for example, in an infected wound.All living organisms on Earth are made up of one of two basic types of cells: eukaryotic cells, in which the genetic material is enclosed within a nuclear membrane, or prokaryotic cells, in which the genetic material is not separated from the rest of the cell. Traditionally, all prokaryotic cells were called bacteria and were classified in the prokaryotic kingdom Monera. However, their classification as Monera, equivalent in taxonomy to the other kingdoms—Plantae, Animalia, Fungi, and Protista—understated the remarkable genetic and metabolic diversity exhibited by prokaryotic cells relative to eukaryotic cells. In the late 1970s American microbiologist Carl Woese pioneered a major change in classification by placing all organisms into three domains—Eukarya, Bacteria (originally called Eubacteria), and Archaea (originally called Archaebacteria)—to reflect the three ancient lines of evolution. The prokaryotic organisms that were formerly known as bacteria were then divided into two of these domains, Bacteria and Archaea. Bacteria and Archaea are superficially similar; for example, they do not have intracellular organelles, and they have circular DNA. However, they are fundamentally distinct, and their separation is based on the genetic evidence for their ancient and separate evolutionary lineages, as well as fundamental differences in their chemistry and physiology. Members of these two prokaryotic domains are as different from one another as they are from eukaryotic cells.Exotoxins— Toxic proteins produced during bacterial growth and metabolism and released into the environment.
Phage typing, like serological testing, identifies bacteria according to their response to the test agent, in this case viruses. Phages are viruses that infect specific bacteria. Bacterial susceptibility to phages is determined by growing bacteria on an agar plate, to which solutions of phages that infect only a specific species of bacteria are added. Areas that are devoid of visible bacterial growth following incubation of the plate represent organisms susceptible to the specific phages. Bacteria are microscopic, single-celled organisms. Many don't cause disease and are even beneficial, although some are disease-causing (pathogenic). Viruses are even smaller than bacteria bacteria definition: The definition of bacteria are microorganisms that are the basis of fermentation and infectious diseases. (noun) An example of bacteria are the organisms that cause common human.. In this procedure, bacteria are first stained with crystal violet, then treated with a mordant—a solution that fixes the stain inside the cell (e.g., iodine-KI mixture). The bacteria are then washed with a decolorizing agent, such as alcohol, and counterstained with safranin, a light red dye.
Cell walls protect prokaryotes against changes in osmotic pressure over a wide range. However, sufficiently hypertonic media at concentrations greater than those inside the cell (such as 20% sucrose) cause water loss from the cell by osmosis. Fluid leaves the bacteria causing the cell to contract, which, in turn, causes the cell membrane to separate from the overlying cell wall. This process of cell shrinkage is called plasmolysis. Bacteria (singular bacterium) are minute organisms that often consist of single cells, like the Bacteria are the simplest cellular lifeforms we know of. However, although a bacterial cell is much.. Aerobic bacteria use oxygen to break down pyruvic acid, releasing much more ATP than is produced during glycolysis during the process known as aerobic respiration. In addition, aerobic bacteria have enzymes such as superoxide dismutase capable of breaking down toxic forms of oxygen, such as super-oxide free radicals, which are also formed by aerobic respiration.
All living organisms must find in their environment a source of energy to fuel cellular processes. Bacteria are no different. Phototrophs are organisms that use light as an energy source; those that require organic carbon are called heterotrophs. Autotrophs use carbon dioxide. Lithotrophs oxidize inorganic compounds such as hydrogen or ammonia for energy.Many rod, spiral, and comma-shaped bacteria have whiplike limbs, known as flagella, attached to the outside of their cells. They use these flagella for movement by waving them back and forth. Other bacteria move simply by wiggling their whole cell back and forth. Some bacteria are unable to move at all.
Prokaryotic cells (i.e., Bacteria and Archaea) are fundamentally different from the eukaryotic cells that constitute other forms of life. Prokaryotic cells are defined by a much simpler design than is found in eukaryotic cells. The most-apparent simplification is the lack of intracellular organelles, which are features characteristic of eukaryotic cells. Organelles are discrete membrane-enclosed structures that are contained in the cytoplasm and include the nucleus, where genetic information is retained, copied, and expressed; the mitochondria and chloroplasts, where chemical or light energy is converted into metabolic energy; the lysosome, where ingested proteins are digested and other nutrients are made available; and the endoplasmic reticulum and the Golgi apparatus, where the proteins that are synthesized by and released from the cell are assembled, modified, and exported. All of the activities performed by organelles also take place in bacteria, but they are not carried out by specialized structures. In addition, prokaryotic cells are usually much smaller than eukaryotic cells. The small size, simple design, and broad metabolic capabilities of bacteria allow them to grow and divide very rapidly and to inhabit and flourish in almost any environment. Bacteria ; common noun bacteria, singular bacterium) are a type of biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length.. . Geometric population growth occurs during the log, or exponential phase, when metabolic activity is most intense and cell reproduction exceeds cell death . Following the log phase, the growth rate slows and the production of new cells equals the rate of cell death. This period, known as the stationary phase, involves the establishment of an equilibrium in population numbers and a slowing of the metabolic activities of individual cells. The stationary phase reflects a change in growing condition—for example, a lack of nutrients and/or the accumulation of waste products. The bacteria listed below cover a range of diseases and levels of resistance. All of them present a Like other potentially dangerous bacteria such as E.coli, Streptococcus pyogenes can be found in 5.. Bacteria also attack organisms by releasing chemicals that are poisonous to plants and animals. Such poisons are known as toxins. A familiar toxin-producing bacterium is Clostridium tetani, responsible for the disease known as tetanus. Tetanus is a condition in which one's muscles are paralyzed, explaining its common name of lockjaw. A related bacterium, Clostridium botulinum, releases a toxin that causes the most severe form of food poisoning, botulism.
Bacteria are often thought of as bad, but many are helpful. We would not exist without them. The oxygen we breathe was probably created by the activity of bacteria.Bacteria react to a sudden change in their environment by expressing or repressing the expression of a whole lost of genes. This response changes the properties of both the interior of the organism and its surface chemistry . A well-known example of this adaptation is the so-called heat shock response of Escherichia coli. The name derives from the fact that the response was first observed in bacteria suddenly shifted to a higher growth temperature.The first antibiotic was discovered in 1929. Since then, a myriad of naturally occurring and chemically synthesized antibiotics have been used to control bacteria. Introduction of an antibiotic is frequently followed by the development of resistance to the agent. Resistance is an example of the adaptation of the bacteria to the antibacterial agent.
As the drawing of the anatomy of a typical bacterium shows, the cytoplasm of all bacteria is enclosed within a cell membrane that is itself surrounded by a rigid cell wall. Bacteria also produce a thick, jelly-like material on the surface of the cell wall. When that material forms a distinct outside layer, it is known as a capsule. Bacteria (singular: bacterium) are a large domain of prokaryotic microorganisms, generally a few micrometers in length. Bacteria have many shapes, which range from rods to spirals to spheres.. Antibiotics are typically used to treat bacterial infections. However, in recent years, improper and unnecessary use of antibiotics has promoted the spread of several strains of antibiotic-resistant bacteria.In 2009, researchers published findings suggesting that women with obesity were more likely to have a particular kind of bacteria, Selenomonas noxia (S. noxia), in their mouth.
Bacteria synthesize special DNA-cutting enzymes (known as restriction enzymes) that destroy the DNA of phages that do not normally infect them. Purified restriction enzymes are used in the laboratory to slice pieces of DNA from one organism and insert them into the genetic material of another organism as mentioned above.Microbiologists have accumulated and organized the known characteristics of different bacteria in a reference book called Bergey's Manual of Systematic Bacteriology (the first edition of which was written primarily by David Hendricks Bergey of the University of Pennsylvania in 1923).Most bacteria thrive at temperatures at or around that of the human body 98.6°F (37°C), and some, such as Escherichia coli, are normal parts of the human intestinal flora. These organisms are mesophiles (moderate-temperature-loving), with an optimum growth temperature between 77°F (25°C) and 104°F (40°C). Mesophiles have adapted to thrive in temperatures close to that of their host.
Bacteria adapt to other environmental conditions as well. These include adaptations to changes in temperature, pH, concentrations of ions such as sodium, and the nature of the surrounding support. An example of the latter is the response shown by Vibrio parahaemolyticus to growth in a watery environment versus a more viscous environment. In the more viscous setting, the bacteria adapt by forming what are called swarmer cells. These cells adopt a different means of movement, which is more efficient for moving over a more solid surface. This adaptation is under tight genetic control, involving the expression of multiple genes. Bacteria are microscopic, single-cell organisms that live almost everywhere. Bacteria live in every climate and location on earth. Some are airborne while others live in water or soil Bacteria are single celled microorganisms and belong to the group of Prokaryotics. A germ is a non medical term that is used to refer to a microorganism, especially the one that can cause any disease Some bacteria breakdown chemical & oil spills. Some cause disease. Move by flagella, gliding over Developed in 1884 by Danish microbiologist, Hans Gram. Bacteria are stained purple with Crystal..
Fermentation bacteria are anaerobic, but use organic molecules as their final electron acceptor to produce fermentation end-products. Streptococcus, Lactobacillus, and Bacillus, for example, produce lactic acid , while Escherichia and Salmonella produce ethanol , lactic acid, succinic acid, acetic acid , CO2, and H2.The genus and species names of bacteria often reflect their shape; for example, the Bacillus family of bacteria are bacilli- or rod-shaped. Others are named for their founders (e.g. Yersinia pestis, the causative agent of bubonic plague, is named for Alexandre Yersin) or for their preferred habitat (e.g., Thermoplasma prefer temperatures up to 149°F, or 65°C).Among the gram positive toxin-producing bacteria are Clostridium tetani, which causes tetanus, an often fatal paralytic disease of muscles; Clostridium botulinum, which causes botulism, a form of potentially lethal food poisoning ; and Staphylococcus aureus, which also causes a form of food poisoning (gastroenteritis).Cell walls protect prokaryotes against changes in osmotic pressure over a wide range. However, sufficiently hypertonic media at concentrations greater than those inside the cell (such as 20% sucrose) cause water loss from the cell by osmosis . Fluid leaves the bacteria causing the cell to contract, which, in turn, causes the cell membrane to separate from the overlying cell wall. This process of cell shrinkage is called plasmolysis.
The identification schemes of Bergey's Manual are based on morphology (e.g., coccus, bacillus), staining (gram-positive or negative), cell wall composition (e.g., presence or absence of peptidoglycan), oxygen requirements (e.g., aerobic, facultatively anaerobic) and biochemical tests (e.g., which sugars are aerobically metabolized or fermented). Bacteria Divide and Multiply. Factors that affect the growth of bacteria. Reproduction by fission and endospores. Other reproductive methods of.. Before Koch, many others had put forth the germ theory of disease, arguing that certain diseases are caused and transmitted by specific microorganisms. However, until Koch, no one had been able to prove this theory. With his identification of the anthrax bacillus, Koch not only demonstrated that this theory was true, but he also established the rules for properly identifying the cause of a disease. Called "Koch's postulates," these rules guided many a researcher in the right direction, and they still hold true today. Bacteria cause many common infections such as pneumonia, wound infections, bloodstream infections (sepsis) and sexually transmitted diseases like gonorrhea, and have also been responsible for several..
Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list. On the surface of some bacteria are short, hairlike, proteinaceous projections that may arise at the ends of the cell or over the entire surface. These projections, called fimbriae, let the bacteria adhere to surfaces. For example, fimbriae on the bacterium Neisseria gonorrhoea, which causes gonorrhea, allow these organisms to attach to mucous membranes.Toxins— Proteins produced by bacteria that are toxic to host cells. Endotoxin is a component of the cell wall of gram-negative bacteria; exotoxin is secreted by both gram-negative and gram-positive bacteria.Many of the bacteria in the body play an important role in human survival. Bacteria in the digestive system break down nutrients, such as complex sugars, into forms the body can use. Bacteria, Bacteria Structure. 18,347 views. Published on Jul 12, 2017. Microorganism : Bacteria : Structure, Classification and Morphology
Finally, bacteria are involved in the production of many foods eaten humans. For example, bacteria that cause milk to become sour are used in the production of cottage cheese, buttermilk, and yogurt. Vinegar and sauerkraut are also produced by the action of bacteria on ethyl alcohol and cabbage, respectively.. Appert developed tables that instructed how long such containers should be boiled, depending upon the type of food and size of the container. Today, the food preservation industry includes not only canning, but also freezing and freeze-drying. An important benefit to food preservation is the ability to destroy potentially lethal contamination by Clostridium botulinum spores.The term bacterial growth generally refers to the growth of a group of bacteria rather than a single cell. Single cells generally do not get larger in size, so the term growth refers to the reproduction of cells.The dynamics of a population of bacteria change during binary fission. The doubling time, or time required for one parent cell to produce two daughter cells, varies by bacteria species and strain and also by the environmental conditions. All bacteria exhibit a characteristic pattern of growth when introduced to a new medium; this is known as the growth curve. There are four phases of the growth curve:Clostridium is an example of an endospore-forming bacterium. There are about 100 species of Clostridium, including Clostridium botulinim (C. botulinim) or botulism, responsible for a potentially fatal kind of food poisoning, and Clostridium difficile (C. Difficile), which causes colitis and other intestinal problems.
Difference between bacteria and bacterium. The words both refer to the tiny microscopic organisms that The only difference between the two is that the word 'Bacterium' is singular whereas the word.. Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA). Exogenous infections result from invasion of noncommensal organisms (i.e., those not normally found on the human body). Transmission of exogenous bacteria may occur by various routes, including inhalation of aerosolized organisms, ingestion (e.g., contaminated food or utensils), or direct contact of a wound or mucous membrane with organisms.An important facet of combating antibiotic resistance is to be careful about their use. "It's so important for us to use antibiotics intelligently," Crnich told LiveScience. "You only want to use an antibiotic when you have a clear-cut bacterial infection."—A method for identifying bacteria according to their response to bacteriophages, which are viruses that infect specific bacteria.
Prokaryotic and eukaryotic cells differ in many other ways, including lipid composition, structure of key metabolic enzymes, responses to antibiotics and toxins, and the mechanism of expression of genetic information. Eukaryotic organisms contain multiple linear chromosomes with genes that are much larger than they need to be to encode the synthesis of proteins. Substantial portions of the ribonucleic acid (RNA) copy of the genetic information (deoxyribonucleic acid, or DNA) are discarded, and the remaining messenger RNA (mRNA) is substantially modified before it is translated into protein. In contrast, bacteria have one circular chromosome that contains all of their genetic information, and their mRNAs are exact copies of their genes and are not modified. There are trillions of bacteria on Earth, but all can be grouped into a relatively small number of types. This classification aids recognition and understanding of bacteria This is a new high definition (HD) dramatic video choreographed to powerful music that introduces the viewer/student to Bacteria. It is designed as a.. The skin is the body's first line of defense against infection by bacteria and other microorganisms, although it supports enormous numbers of bacteria itself, especially Staphylococcus and Streptococcus species. Sometimes these bacteria are only dangerous if they enter a break in the skin or invade a wound, for example, the potentially fatal staphylococcal toxic shock syndrome . Among other common bacterial skin ailments are acne , caused by Propionibacterium acnes and superficial infection of the outer ear canal, caused by Pseudomonas aeruginosa.
In addition to helping bacteriologists better classify bacteria, the various laboratory tests are valuable tools for identifying disease-causing organisms. This is especially important when physicians must determine which antibiotic or other medication to use to treat an infection.Anaerobic bacteria use inorganic substances other than oxygen as a final electron acceptor. For example, Pseudomonas and Bacillus reduce nitrate ion (NO3 ) to nitrite ion (NO2 ), nitrous oxide (N2O) or nitrogen gas (N2). Clostridium species, which include those that cause tetanus and botulism , are obligate anaerobes. That is, they are not only unable to use molecular oxygen to produce ATP, but are harmed by toxic forms of oxygen formed during aerobic respiration. Unlike aerobic bacteria, obligate anaerobes lack the ability synthesize enzymes to neutralize these toxic forms of oxygen.
Until Koch isolated this microorganism, science was baffled by tuberculosis, not knowing how or whether it actually spread or whether it was simply hereditary. Once he identified the bacillus, however, he was able to show that tuberculosis was caused by a germ that could be carried in the air and passed from one person to another. Until Koch had proven the germ theory of disease once and for all, the science of medicine could not really progress much beyond what it was centuries before when people believed in spontaneous generation (the idea that living things can come from nonliving matter, such as maggots from rotting meat). After Koch, the science of microbiology, which is the study of things that can only be seen with a microscope, could really begin to make progress. Meaning of bacteria. What does bacteria mean? Information and translations of bacteria in the most comprehensive dictionary definitions resource on the web Bacteria adapt to other environmental conditions as well. These include adaptations to changes in temperature, pH, concentrations of ions such as sodium , and the nature of the surrounding support. An example of the latter is the response shown by Vibrio parahaemolyticus to growth in a watery environment versus a more viscous environment. In the more viscous setting, the bacteria adapt by forming what are called swarmer cells. These cells adopt a different means of movement, which is more efficient for moving over a more solid surface. This adaptation is under tight genetic control, involving the expression of multiple genes. Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites: Treating Harmful Bacteria. Medically Reviewed by Dr. Vibhuti Rana. Half of the stool tests I examine show just harmful bacteria and no yeast infection, and many times those bacteria have infected the..
Helpful bacteria. Bacteria make possible the digestion of foods in many kinds of animals. Cows, deer, sheep, and other ruminants, for example, have a large organ known as the rumen in which bacteria live and help break down cellulose fibers and other tough plant materials. In humans, bacteria known as Escherichia coli (E. coli ) occur everywhere in the digestive system, aiding in the breakdown of many kinds of foods. Bacteria are also responsible for the production of vitamin K and certain B vitamins.See also Antisepsis; Biodegradable substances; Biodiversity; Composting; Microbial genetics; Origin of life; Water microbiology; Nitrogen fixation.In October 2000, a team of biologists claimed to have revived a bacterium that existed 250 million years ago, well before the age of the dinosaurs. They found the bacterium in a drop of fluid trapped in a crystal of rock salt that had been excavated from an air duct supplying a radioactive waste dump 1,850 feet (564 meters) below Earth's surface near Carlsbad, New Mexico. When the biologists drilled into the pocket of fluid in the crystal and mixed nutrients with the fluid, bacteria soon appeared. However, other scientists quickly suggested that the bacteria that grew was simply modern bacteria that had infected the crystal sample. The questioning scientists also pointed out that it would be impossible for the bacterium's DNA (a complex molecule that stores and transmits genetic information) to have survived more than a few thousand years, at best.
Bacteria are mostly unicellular organisms that lack chlorophyll and are among the smallest living things on earth—only viruses are smaller. Multiplying rapidly under favorable conditions, bacteria can aggregate into colonies of millions or even billions of organisms within a space as small as a drop of water .Bacteria react to a sudden change in their environment by expressing or repressing the expression of a whole lost of genes. This response changes the properties of both the interior of the organism and its surface chemistry. A well-known example of this adaptation is the so-called heat shock response of Escherichia coli. The name derives from the fact that the response was first observed in bacteria suddenly shifted to a higher growth temperature.
There are bacteria that can cause a multitude of illnesses. They are responsible for many of the infectious diseases like pneumonia, tuberculosis, diphtheria, syphilis, tooth decay. Their effects can be rectified by taking antibiotics and prescribed medication.Bacteria lack a membrane-bound nucleus and other internal structures and are therefore ranked among the unicellular life-forms called prokaryotes. Prokaryotes are the dominant living creatures on Earth, having been present for perhaps three-quarters of Earth history and having adapted to almost all available ecological habitats. As a group, they display exceedingly diverse metabolic capabilities and can use almost any organic compound, and some inorganic compounds, as a food source. Some bacteria can cause diseases in humans, animals, or plants, but most are harmless and are beneficial ecological agents whose metabolic activities sustain higher life-forms. Other bacteria are symbionts of plants and invertebrates, where they carry out important functions for the host, such as nitrogen fixation and cellulose degradation. Without prokaryotes, soil would not be fertile, and dead organic material would decay much more slowly. Some bacteria are widely used in the preparation of foods, chemicals, and antibiotics. Studies of the relationships between different groups of bacteria continue to yield new insights into the origin of life on Earth and mechanisms of evolution. Bacteria are a type of biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes.. Aerobic bacteria use oxygen to break down pyruvic acid, releasing much more ATP than is produced during glycolysis during the process known as aerobic respiration . In addition, aerobic bacteria have enzymes such as superoxide dismutase capable of breaking down toxic forms of oxygen, such as superoxide free radicals, which are also formed by aerobic respiration. Bacteria do not pass the membrane filter, and can be separated and analyzed in the laboratory. Each separate cell develops to a colony forming unit (cfu), and these can be counted. Faecal streptococci
Most gram-negative bacteria (for example, Salmonella typhi, the cause of typhoid fever) produce endotoxins, toxins that are part of the bacterial cell wall.The earth is estimated to hold at least 5 nonillion bacteria, and much of the earth’s biomass is thought to be made up of bacteria.
Bacteria can use most organic and some inorganic compounds as food, and some can survive extreme conditions.Not only is fermentation useful for preserving foods, but some of these foods may offer health benefits. Bacteria and viruses differ in their structure and their response to medications. Less than 1% of bacteria cause disease. Most are beneficial for our good health and the health of Earth's ecosystems Bacteria are prokaryotic, single-celled microscopic organisms present almost everywhere. Explore the structure of bacteria, classification of bacteria and its reproduction Other bacteria can cause infections. Several bacteria — ranging from so-called group A Streptococcus, Clostridium perfringens (C. perfringens), E. coli and S. aureus can cause a rare but severe soft tissue infection called necrotizing fasciitis (sometimes called flesh-eating bacteria). According to the Centers for Disease Control and Prevention (CDC), this infection affects the tissues surrounding muscles, nerves, fat and blood vessels; it can be treated, especially when caught early.
Bacteria are microscopic, single-celled organisms that thrive in diverse environments. These organisms can live in soil, the ocean and inside the human gut.The most fundamental technique for classifying bacteria is the gram stain, developed in 1884 by Danish scientist Christian Gram (1853–1938). It is called a differential stain because it differentiates among bacteria and can be used to distinguish among them, based on differences in their cell wall.
Bacteria are thought to have been the first organisms to appear on earth, about 4 billion years ago. The oldest known fossils are of bacteria-like organisms. bacteria meaning, definition, what is bacteria: very small living things, some of which: Learn more
Pasteur described the spoilage by bacteria of alcohol during fermentation as being a “disease” of wine and beer. His work was thus vital to the later idea that human diseases could also be caused by microorganisms, and that heating can destroy them.Among the gram positive toxin-producing bacteria are Clostridium tetani, which causes tetanus, an often fatal paralytic disease of muscles; Clostridium botulinum, which causes botulism, a form of potentially lethal food poisoning; and Staphylococcus aureus, which also causes a form of food poisoning (gastroenteritis).
Hawkey, P. M. "The Origins and Molecular Basis of Antibiotic Resistance." British Medical Journal (September 5, 1998): 657-660.The second category of adaptive resistance is called acquired resistance. This resistance is almost always due to a change in the genetic make-up of the bacterial genome. Acquired resistance can occur because of mutation or as a response by the bacteria to the selective pressure imposed by the antibacterial agent. Once the genetic alteration that confers resistance is present, it can be passed on to subsequent generations. Acquired adaptation and resistance of bacteria to some clinically important antibiotics has become a great problem in the last decade of the twentieth century.Bacteria may be classified by their biochemical composition, and analysis of the protein and lipid content of an organism is often a means of identification. Growth requirements are often used as a means of classification: Mycobacterium tuberculosis, for example, is an obligate aerobe and therefore requires oxygen for growth, while the presence of oxygen is toxic to the anaerobe Clostridium tetani.
Beginning in the 1930s, the development of synthetic anti-bacterial compounds called sulfa drugs further stimulated the field of anti-bacterial drug research. The many different anti-bacterial drugs available today work in a variety of ways, such as the inhibition of synthesis of cell walls, of proteins, or of DNA or RNA.A few different criteria are used to classify bacteria. The organisms can be distinguished by the nature of their cell walls, by their shape, or by differences in their genetic makeup. Bacteria can be classified according to many features, such as morphology (their shape), their staining with dyes (e.g Gram staining), their biochemical properties, or their DNA sequences Bacteria were first discovered in 1683 by the Dutch microscopist, Anton van Leeuwenhoek (1632–1723), who called them "little animalcules." However, it was not until the middle of the nineteenth century that biologists began to understand bacteria better. Although they were considered to be animals and then plants, bacteria eventually came to be placed in the Monera kingdom since they do not have a distinct nucleus (a cell's control center). Members of the four other kingdoms (Protista, Fungi, Plantae, and Animalia) all are eukaryotic, meaning their cells have nuclei kept within a membrane. Most bacteria are single-celled and can be grouped according to three definite shapes. Rod-shaped bacteria are called "bacilli." One species of bacillus causes the cattle disease anthrax. Spherical or round bacteria are known as "cocci." Certain "cocci" can cause staph or strep infections. Bacteria that have a helical or coiled shape resembling corkscrews are known as "spirilla." Spirilla are often carried by rats and can cause a form of rat-bite fever. Bacteria can also sometimes be in the shape of a fat comma, and these are called "vibroids." A particularly nasty form of this bacteria causes cholera.