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104-595: A delicacy is a rare food item that is considered highly desirable, sophisticated, or peculiarly distinctive within a given culture or region. A delicacy may have an unusual flavor or be expensive compared to everyday foods. Delicacies vary across countries, customs, and ages. Some delicacies are confined to a certain culture, such as fugu in Japan and ant larvae ( escamoles ) in Mexico , or may refer to specific local products, such as porcino , venison or anchovy . Culture plays

208-406: A nucleus and rarely harbour membrane -bound organelles . Although the term bacteria traditionally included all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotes consist of two very different groups of organisms that evolved from an ancient common ancestor . These evolutionary domains are called Bacteria and Archaea . The word bacteria

312-543: A potential difference analogous to a battery. The general lack of internal membranes in bacteria means these reactions, such as electron transport , occur across the cell membrane between the cytoplasm and the outside of the cell or periplasm . However, in many photosynthetic bacteria, the plasma membrane is highly folded and fills most of the cell with layers of light-gathering membrane. These light-gathering complexes may even form lipid-enclosed structures called chlorosomes in green sulfur bacteria . Bacteria do not have

416-409: A sodium channel blocker , paralyzes the muscles while the victim stays fully conscious; the poisoned victim is unable to breathe and eventually dies from asphyxiation . There is no known antidote for fugu poison. The standard treatment is to support the respiratory and circulatory systems until the poison is metabolized and excreted by the victim's body. Researchers have determined that

520-404: A terminal electron acceptor in a redox reaction . Chemotrophs are further divided by the types of compounds they use to transfer electrons. Bacteria that derive electrons from inorganic compounds such as hydrogen, carbon monoxide , or ammonia are called lithotrophs , while those that use organic compounds are called organotrophs . Still, more specifically, aerobic organisms use oxygen as

624-744: A bacterial strain. However, liquid growth media are used when the measurement of growth or large volumes of cells are required. Growth in stirred liquid media occurs as an even cell suspension, making the cultures easy to divide and transfer, although isolating single bacteria from liquid media is difficult. The use of selective media (media with specific nutrients added or deficient, or with antibiotics added) can help identify specific organisms. Most laboratory techniques for growing bacteria use high levels of nutrients to produce large amounts of cells cheaply and quickly. However, in natural environments, nutrients are limited, meaning that bacteria cannot continue to reproduce indefinitely. This nutrient limitation has led

728-627: A chef at two- Michelin star "Fugu Fukuji" in Tokyo was suspended from his post. The chef served fugu liver to a customer who, despite being warned of the risks, specifically asked that it be provided. The 35-year-old customer subsequently required hospital treatment for mild symptoms of tetrodotoxin paralysis, but made a full recovery. Five men were poisoned at a restaurant in Wakayama in March 2015 after specifically asking for liver. In December 2020, 3 people in

832-424: A disorganised slime layer of extracellular polymeric substances to a highly structured capsule . These structures can protect cells from engulfment by eukaryotic cells such as macrophages (part of the human immune system ). They can also act as antigens and be involved in cell recognition, as well as aiding attachment to surfaces and the formation of biofilms. The assembly of these extracellular structures

936-413: A few micrometres in thickness to up to half a metre in depth, and may contain multiple species of bacteria, protists and archaea. Bacteria living in biofilms display a complex arrangement of cells and extracellular components, forming secondary structures, such as microcolonies , through which there are networks of channels to enable better diffusion of nutrients. In natural environments, such as soil or

1040-415: A few species are visible to the unaided eye—for example, Thiomargarita namibiensis is up to half a millimetre long, Epulopiscium fishelsoni reaches 0.7 mm, and Thiomargarita magnifica can reach even 2 cm in length, which is 50 times larger than other known bacteria. Among the smallest bacteria are members of the genus Mycoplasma , which measure only 0.3 micrometres, as small as

1144-426: A fixed size and then reproduce through binary fission , a form of asexual reproduction . Under optimal conditions, bacteria can grow and divide extremely rapidly, and some bacterial populations can double as quickly as every 17 minutes. In cell division, two identical clone daughter cells are produced. Some bacteria, while still reproducing asexually, form more complex reproductive structures that help disperse

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1248-413: A fugu's tetrodotoxin comes from eating other animals infested with tetrodotoxin-laden bacteria , to which the fish develops insensitivity over time. Whether tetrodotoxin is sequestered from or produced by symbiotic bacteria is still debated. As such, efforts have been made in research and aquaculture to allow farmers to produce safe fugu. Farmers now produce poison-free fugu by keeping the fish away from

1352-490: A list that shows which species' body parts can be consumed. The list names safe genera including pufferfish of the Lagocephalus and Sphoeroides genera and the related porcupinefish ( Harisenbon ) of the family Diodontidae . Strict fishing regulations are now in place to protect fugu populations from depletion. Most fugu is now harvested in the spring during the spawning season and then farmed in floating cages in

1456-408: A membrane-bound nucleus, and their genetic material is typically a single circular bacterial chromosome of DNA located in the cytoplasm in an irregularly shaped body called the nucleoid . The nucleoid contains the chromosome with its associated proteins and RNA . Like all other organisms , bacteria contain ribosomes for the production of proteins, but the structure of the bacterial ribosome

1560-528: A particular organism or group of organisms ( syntrophy ). Bacterial growth follows four phases. When a population of bacteria first enter a high-nutrient environment that allows growth, the cells need to adapt to their new environment. The first phase of growth is the lag phase , a period of slow growth when the cells are adapting to the high-nutrient environment and preparing for fast growth. The lag phase has high biosynthesis rates, as proteins necessary for rapid growth are produced. The second phase of growth

1664-474: A prized seafood delicacy in the Chinese culinary landscape as well. There are close to 200 species in the family Tetraodontidae (pufferfish), a family of primarily marine and estuarine fish of the order Tetraodontiformes . However, only some of them are eaten and traded as "fugu". Fugu contains lethal amounts of the poison tetrodotoxin in its organs, especially the liver , ovaries , eyes, and skin. The poison,

1768-415: A process called transformation . Many bacteria can naturally take up DNA from the environment, while others must be chemically altered in order to induce them to take up DNA. The development of competence in nature is usually associated with stressful environmental conditions and seems to be an adaptation for facilitating repair of DNA damage in recipient cells. Second, bacteriophages can integrate into

1872-534: A role in determining what is considered a delicacy. The long-standing tradition and practice of insect consumption represented in Oaxaca, Mexico has occurred for centuries. The availability of foods or particular ingredients may determine the types of delicacies associated with different cultures. Fugu Fugu possesses a potentially fatal poison known as tetrodotoxin , therefore necessitating meticulous preparation to eliminate poisonous components and prevent

1976-711: A seafood delicacy, sometimes resulting in poisoning incidents. Japanese restaurateur Nobuyoshi Kuraoka waged a five-year legal battle with the U.S. Food and Drug Administration to allow the exclusive import of the Japanese Tiger puffer into his Manhattan restaurant, with the license finally being granted to him in 1989. By 2003, only seventeen restaurants in the United States were licensed to serve fugu; fourteen in New York State , twelve of which are in New York City . In

2080-517: A service each year at the height of the fugu season, releasing hundreds of caught fugu into the Sumida River . A similar ceremony is also held at another large market in Shimonoseki. A rakugo , or humorous short story, tells of three men who prepared a fugu stew but were unsure whether it was safe to eat. To test the stew, they gave some to a beggar. When it did not seem to do him any harm, they ate

2184-425: A single continuous stretch of DNA. Although several different types of introns do exist in bacteria, these are much rarer than in eukaryotes. Bacteria, as asexual organisms, inherit an identical copy of the parent's genome and are clonal . However, all bacteria can evolve by selection on changes to their genetic material DNA caused by genetic recombination or mutations . Mutations arise from errors made during

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2288-427: A single linear chromosome, while some Vibrio species contain more than one chromosome. Some bacteria contain plasmids , small extra-chromosomal molecules of DNA that may contain genes for various useful functions such as antibiotic resistance , metabolic capabilities, or various virulence factors . Bacteria genomes usually encode a few hundred to a few thousand genes. The genes in bacterial genomes are usually

2392-424: A small domestic luxury market that has been operating under license since 2003. Bacteria See § Phyla Bacteria ( / b æ k ˈ t ɪər i ə / ; sg. : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell . They constitute a large domain of prokaryotic microorganisms . Typically a few micrometres in length, bacteria were among

2496-649: A source of electrons and a substrate for carbon anabolism . In many ways, bacterial metabolism provides traits that are useful for ecological stability and for human society. For example, diazotrophs have the ability to fix nitrogen gas using the enzyme nitrogenase . This trait, which can be found in bacteria of most metabolic types listed above, leads to the ecologically important processes of denitrification , sulfate reduction , and acetogenesis , respectively. Bacterial metabolic processes are important drivers in biological responses to pollution ; for example, sulfate-reducing bacteria are largely responsible for

2600-785: A thick peptidoglycan cell wall like a Gram-positive bacterium, but also a second outer layer of lipids. In many bacteria, an S-layer of rigidly arrayed protein molecules covers the outside of the cell. This layer provides chemical and physical protection for the cell surface and can act as a macromolecular diffusion barrier . S-layers have diverse functions and are known to act as virulence factors in Campylobacter species and contain surface enzymes in Bacillus stearothermophilus . Flagella are rigid protein structures, about 20 nanometres in diameter and up to 20 micrometres in length, that are used for motility . Flagella are driven by

2704-417: A three- dimensional random walk . Bacterial species differ in the number and arrangement of flagella on their surface; some have a single flagellum ( monotrichous ), a flagellum at each end ( amphitrichous ), clusters of flagella at the poles of the cell ( lophotrichous ), while others have flagella distributed over the entire surface of the cell ( peritrichous ). The flagella of a group of bacteria,

2808-453: A toxicity inspection, and other tests." In Korean cuisine , edible pufferfish are prepared in various ways including gui (grilling), jorim (simmering), jjim , Bulgogi , Hoe (raw fish) and guk (soup). Despite the comparatively lower consumption rate of the fish in comparison to other East Asian nations, the prevalence of fugu restaurants has experienced a significant surge across Chinese urban areas since 2016. The fish

2912-685: Is Takefuku , in the upscale Ginza district in Tokyo with Zuboraya being another popular restaurant chain in Osaka that both offer the celebrated seafood delicacy. The fugu is cleaned of its most toxic parts in Japan and freeze-flown to the United States under license in clearly customized plastic containers. Fugu chefs who cook in American restaurants are trained under the same rigorous and stringent specifications as in Japan. Pufferfish native to American waters, particularly

3016-410: Is also made into everyday objects like wallets or waterproof boxes. Scientists at Nagasaki University have succeeded in culturing non-toxic torafugu by restricting the fish's diet. The experiment included raising over 5,000 fish between the years 2001–2004, and analyzing the toxicity of muscle, skin, gonads, livers, and other organs. The team concluded that the amount of tetrodotoxin in all those parts

3120-480: Is caused by a toxin released by the bacteria that grow from the spores. Clostridioides difficile infection , a common problem in healthcare settings, is caused by spore-forming bacteria. Bacteria exhibit an extremely wide variety of metabolic types. The distribution of metabolic traits within a group of bacteria has traditionally been used to define their taxonomy , but these traits often do not correspond with modern genetic classifications. Bacterial metabolism

3224-412: Is classified into nutritional groups on the basis of three major criteria: the source of energy , the electron donors used, and the source of carbon used for growth. Phototrophic bacteria derive energy from light using photosynthesis , while chemotrophic bacteria breaking down chemical compounds through oxidation , driving metabolism by transferring electrons from a given electron donor to

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3328-536: Is dependent on bacterial secretion systems . These transfer proteins from the cytoplasm into the periplasm or into the environment around the cell. Many types of secretion systems are known and these structures are often essential for the virulence of pathogens, so are intensively studied. Some genera of Gram-positive bacteria, such as Bacillus , Clostridium , Sporohalobacter , Anaerobacter , and Heliobacterium , can form highly resistant, dormant structures called endospores . Endospores develop within

3432-534: Is determined by the bacterial cell wall and cytoskeleton and is important because it can influence the ability of bacteria to acquire nutrients, attach to surfaces, swim through liquids and escape predators . Multicellularity . Most bacterial species exist as single cells; others associate in characteristic patterns: Neisseria forms diploids (pairs), streptococci form chains, and staphylococci group together in "bunch of grapes" clusters. Bacteria can also group to form larger multicellular structures, such as

3536-441: Is different from that of eukaryotes and archaea. Some bacteria produce intracellular nutrient storage granules, such as glycogen , polyphosphate , sulfur or polyhydroxyalkanoates . Bacteria such as the photosynthetic cyanobacteria , produce internal gas vacuoles , which they use to regulate their buoyancy, allowing them to move up or down into water layers with different light intensities and nutrient levels. Around

3640-414: Is essential to the survival of many bacteria, and the antibiotic penicillin (produced by a fungus called Penicillium ) is able to kill bacteria by inhibiting a step in the synthesis of peptidoglycan. There are broadly speaking two different types of cell wall in bacteria, that classify bacteria into Gram-positive bacteria and Gram-negative bacteria . The names originate from the reaction of cells to

3744-457: Is forbidden altogether in the European Union . In Switzerland , the importation of fugu is legal, but only as long as it is purchased exclusively for private consumption. Fugu chefs who cook in American restaurants are trained under the same rigorous and stringent specifications as in Japan. Pufferfish native to American waters, particularly the genus Spheroides , have also been consumed as

3848-529: Is made of about 20 proteins, with approximately another 30 proteins required for its regulation and assembly. The flagellum is a rotating structure driven by a reversible motor at the base that uses the electrochemical gradient across the membrane for power. Bacteria can use flagella in different ways to generate different kinds of movement. Many bacteria (such as E. coli ) have two distinct modes of movement: forward movement (swimming) and tumbling. The tumbling allows them to reorient and makes their movement

3952-468: Is made primarily of phospholipids . This membrane encloses the contents of the cell and acts as a barrier to hold nutrients, proteins and other essential components of the cytoplasm within the cell. Unlike eukaryotic cells , bacteria usually lack large membrane-bound structures in their cytoplasm such as a nucleus , mitochondria , chloroplasts and the other organelles present in eukaryotic cells. However, some bacteria have protein-bound organelles in

4056-496: Is motile in liquid or solid media. Several Listeria and Shigella species move inside host cells by usurping the cytoskeleton , which is normally used to move organelles inside the cell. By promoting actin polymerisation at one pole of their cells, they can form a kind of tail that pushes them through the host cell's cytoplasm. A few bacteria have chemical systems that generate light. This bioluminescence often occurs in bacteria that live in association with fish, and

4160-617: Is no known antidote , and treatment consists of emptying the stomach, administering activated charcoal to bind the toxin, and putting the person on life support until the poison has worn off. Toxicologists have been working on developing an antidote for tetrodotoxin. Between 1996 and 2006, statistics from the Tokyo Bureau of Social Welfare and Public Health indicate 20–44 annual incidents of fugu poisoning in Japan, some affecting multiple diners. Annually, 34–64 people were hospitalized and 0–6 died, with an average fatality rate of 6.8%. Of

4264-411: Is only made in specific regions of Ishikawa Prefecture ( Mikawa district , Ono district, Kanaiwa district, and Wajima ), and only the traditional method is permitted. Non-professionals are warned against attempting the process. After one year of pickling, about 10% of the toxin is suggested to remain, and after the full three years the product is "only sold after having been checked for safety through

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4368-480: Is only sold in a processed form (without organs) with a test certificate from the fishery. In 2023, processed raw farmed fugu across China is sold to ordinary customers online. Most Japanese cities have one or more fugu restaurants, perhaps in clusters because of earlier restrictions, as proximity made it easier when transporting the seafood delicacy so as to preserve its long-term freshness upon being served to potential patrons. A famous restaurant specializing in fugu

4472-444: Is the stationary phase and is caused by depleted nutrients. The cells reduce their metabolic activity and consume non-essential cellular proteins. The stationary phase is a transition from rapid growth to a stress response state and there is increased expression of genes involved in DNA repair , antioxidant metabolism and nutrient transport . The final phase is the death phase where

4576-440: Is the logarithmic phase , also known as the exponential phase. The log phase is marked by rapid exponential growth . The rate at which cells grow during this phase is known as the growth rate ( k ), and the time it takes the cells to double is known as the generation time ( g ). During log phase, nutrients are metabolised at maximum speed until one of the nutrients is depleted and starts limiting growth. The third phase of growth

4680-676: Is the plural of the Neo-Latin bacterium , which is the Latinisation of the Ancient Greek βακτήριον ( baktḗrion ), the diminutive of βακτηρία ( baktēría ), meaning "staff, cane", because the first ones to be discovered were rod-shaped . The ancestors of bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, about 4 billion years ago. For about 3 billion years, most organisms were microscopic, and bacteria and archaea were

4784-468: The Gram stain , a long-standing test for the classification of bacterial species. Gram-positive bacteria possess a thick cell wall containing many layers of peptidoglycan and teichoic acids . In contrast, Gram-negative bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins . Most bacteria have

4888-542: The Jōmon period that date back more than 2,300 years. The Tokugawa shogunate (1603–1868) prohibited the consumption of fugu in Edo and its area of influence. It became common again as the power of the Shōgunate weakened. In western regions of Japan, where the government's influence was weaker and fugu was easier to obtain, various cooking methods were developed to safely eat them. During

4992-505: The Kansai region of Japan, the slang word teppō , ( 鉄砲 ) meaning musket, rifle or gun , is used for the fish. This is a play of words on the verb ataru ( 当たる ), which can mean to be poisoned or shot. In Shimonoseki region, the ancient pronunciation fuku is more common instead of the modern fugu . The former is also a homonym for good fortune whereas the latter is one for disabled. The Tsukiji fish market fugu association holds

5096-625: The Meiji Era (1867–1912), fugu was again banned in many areas. According to one fugu chef in Tokyo, the Emperor of Japan has never eaten fugu due to an unspecified "centuries old ban". In China, the use of the pufferfish for culinary purposes was already well-established by the Song dynasty as one of the "three delicacies of the Yangtze" ( Chinese : 長江三鮮 ), alongside saury and Reeve's shad , and appears in

5200-525: The Pacific Ocean . The largest wholesale fugu market in Japan is in Shimonoseki . Fugu prices rise in autumn and peak in winter, the best season, because they fatten to survive the cold. Live fish arrive at a restaurant, surviving in a large tank, usually prominently displayed. Prepared fugu is also often available in grocery stores, which must display official license documents. Whole fish may not be sold to

5304-480: The blood–brain barrier is uncertain. In the case of the pufferfish host, at least (see below), their insusceptibility to the poison is thought to result from cysteine asperagine amino acid substitutions in the sequence of their specific types of sodium channel proteins. TTX is not produced by pufferfish and the other aquatic animals from which it has been isolated. Rather, bacteria such as Alteromonas , Shewanella , and Vibrio species infect or cohabit with

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5408-479: The putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps , extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane , to energy. Bacteria also live in mutualistic , commensal and parasitic relationships with plants and animals. Most bacteria have not been characterised and there are many species that cannot be grown in

5512-444: The spirochaetes , are found between two membranes in the periplasmic space. They have a distinctive helical body that twists about as it moves. Two other types of bacterial motion are called twitching motility that relies on a structure called the type IV pilus , and gliding motility , that uses other mechanisms. In twitching motility, the rod-like pilus extends out from the cell, binds some substrate, and then retracts, pulling

5616-546: The vacuum and radiation of outer space , leading to the possibility that bacteria could be distributed throughout the Universe by space dust , meteoroids , asteroids , comets , planetoids , or directed panspermia . Endospore-forming bacteria can cause disease; for example, anthrax can be contracted by the inhalation of Bacillus anthracis endospores, and contamination of deep puncture wounds with Clostridium tetani endospores causes tetanus , which, like botulism ,

5720-452: The 23 incidents reported in Tokyo from 1993 through 2006, only one took place in a restaurant; all others involved people catching and eating the fish. Poisonings through amateur preparation can result from confusion between types of puffer, as well as improper methods. Some may also represent deliberate suicide attempts; Engelbert Kaempfer , a German physician who resided in Japan in the 1690s, reported that an unusually toxic variety of puffer

5824-408: The Chinese culinary sphere, fugu is generally prepared as a soup or braised whole. The fish may also be prepared using traditional Japanese culinary techniques. In the cuisine of Hakusan, Ishikawa , ovaries are served after reducing the toxin level by salting and pickling for three years, in a dish named "blowfish ovaries pickled in rice-bran paste " ( 河豚の卵巣の糠漬け, ふぐのらんそうのぬかづけ ) . The dish

5928-537: The Food Safety Commission of Japan three times to reconsider its ban on fugu liver, stating that its farmed fugu is non-toxic. The FSCJ has rejected the proposals thrice due to "data insufficient to prove safety". NYT reported in 2008 that there is a well-known underground fugu-kimo scene in another Japanese town, Usuki, Ōita . In the case of torafugu , the most common fugu, the cost is between JP¥1000–JP¥4000 (US$ 7–29) per kilogram, depending on

6032-781: The Gram-negative cell wall, and only members of the Bacillota group and actinomycetota (previously known as the low G+C and high G+C Gram-positive bacteria, respectively) have the alternative Gram-positive arrangement. These differences in structure can produce differences in antibiotic susceptibility; for instance, vancomycin can kill only Gram-positive bacteria and is ineffective against Gram-negative pathogens , such as Haemophilus influenzae or Pseudomonas aeruginosa . Some bacteria have cell wall structures that are neither classically Gram-positive or Gram-negative. This includes clinically important bacteria such as mycobacteria which have

6136-604: The Philippines died, while 4 more were hospitalized after eating pufferfish. In March 2023, an elderly woman and her husband in Malaysia died after consuming pufferfish purchased from a fishmonger. In January 2024, a Brazilian man, 46, died after eating pufferfish gifted to him by a friend. Although not as frequently consumed as in Japan and Korea, fugu is still considered a delicacy and served across restaurants in Beijing . Within

6240-791: The animal species from which TTX is isolated, and a bacterial biosynthetic pathway for its production has been rationalized. In animal studies with mice, the median lethal dose of TTX was found to be 232 μg per kg body weight. Tetrodotoxin levels are affected by preparation (removal of most toxic materials, treatments such as curing and pickling, see below); it is, however, reportedly not significantly affected by cooking. Despite its toxicity, TTX has clinical therapeutic applications, being evaluated in phase II and III clinical trials to be effective for treating cancer-related pain without increasing serious adverse events. The inhabitants of Japan have eaten fugu for centuries. Fugu bones have been found in several shell middens , called kaizuka , from

6344-425: The archaeal/eukaryotic lineage. The most recent common ancestor (MRCA) of bacteria and archaea was probably a hyperthermophile that lived about 2.5 billion–3.2 billion years ago. The earliest life on land may have been bacteria some 3.22 billion years ago. Bacteria were also involved in the second great evolutionary divergence, that of the archaea and eukaryotes. Here, eukaryotes resulted from

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6448-455: The atmosphere and one cubic metre of air holds around one hundred million bacterial cells. The oceans and seas harbour around 3 x 10 bacteria which provide up to 50% of the oxygen humans breathe. Only around 2% of bacterial species have been fully studied. Size . Bacteria display a wide diversity of shapes and sizes. Bacterial cells are about one-tenth the size of eukaryotic cells and are typically 0.5–5.0  micrometres in length. However,

6552-448: The bacteria – see § Aquaculture below. Tetrodotoxin (TTX) is a natural product that has been isolated not only from pufferfish, but also octopuses, crabs, shellfish, frogs, newts, and other aquatic animals (see below). It is a potent neurotoxin that shuts down electrical signaling in nerves ; it acts via interaction with components of the sodium channels in the cell membranes of those cells. Its ability to cross

6656-520: The bacteria have come into contact with in the past, which allows them to block virus replication through a form of RNA interference . Third, bacteria can transfer genetic material through direct cell contact via conjugation . In ordinary circumstances, transduction, conjugation, and transformation involve transfer of DNA between individual bacteria of the same species, but occasionally transfer may occur between individuals of different bacterial species, and this may have significant consequences, such as

6760-444: The bacteria perform separate tasks; for example, about one in ten cells migrate to the top of a fruiting body and differentiate into a specialised dormant state called a myxospore, which is more resistant to drying and other adverse environmental conditions. Biofilms . Bacteria often attach to surfaces and form dense aggregations called biofilms and larger formations known as microbial mats . These biofilms and mats can range from

6864-401: The bacteria run out of nutrients and die. Most bacteria have a single circular chromosome that can range in size from only 160,000 base pairs in the endosymbiotic bacteria Carsonella ruddii , to 12,200,000 base pairs (12.2 Mbp) in the soil-dwelling bacteria Sorangium cellulosum . There are many exceptions to this; for example, some Streptomyces and Borrelia species contain

6968-412: The bacterial chromosome, introducing foreign DNA in a process known as transduction . Many types of bacteriophage exist; some infect and lyse their host bacteria, while others insert into the bacterial chromosome. Bacteria resist phage infection through restriction modification systems that degrade foreign DNA and a system that uses CRISPR sequences to retain fragments of the genomes of phage that

7072-502: The breakdown of oil spills , the production of cheese and yogurt through fermentation , the recovery of gold, palladium , copper and other metals in the mining sector ( biomining , bioleaching ), as well as in biotechnology , and the manufacture of antibiotics and other chemicals. Once regarded as plants constituting the class Schizomycetes ("fission fungi"), bacteria are now classified as prokaryotes . Unlike cells of animals and other eukaryotes , bacterial cells do not contain

7176-437: The cell forward. Motile bacteria are attracted or repelled by certain stimuli in behaviours called taxes : these include chemotaxis , phototaxis , energy taxis , and magnetotaxis . In one peculiar group, the myxobacteria, individual bacteria move together to form waves of cells that then differentiate to form fruiting bodies containing spores. The myxobacteria move only when on solid surfaces, unlike E. coli , which

7280-629: The cytoplasm of the cell; generally, a single endospore develops in each cell. Each endospore contains a core of DNA and ribosomes surrounded by a cortex layer and protected by a multilayer rigid coat composed of peptidoglycan and a variety of proteins. Endospores show no detectable metabolism and can survive extreme physical and chemical stresses, such as high levels of UV light , gamma radiation , detergents , disinfectants , heat, freezing, pressure, and desiccation . In this dormant state, these organisms may remain viable for millions of years. Endospores even allow bacteria to survive exposure to

7384-419: The cytoplasm which compartmentalise aspects of bacterial metabolism, such as the carboxysome . Additionally, bacteria have a multi-component cytoskeleton to control the localisation of proteins and nucleic acids within the cell, and to manage the process of cell division . Many important biochemical reactions, such as energy generation, occur due to concentration gradients across membranes, creating

7488-432: The deaths. In March 2008, a fisherman in the Philippines died and members of his family became ill from pufferfish. The previous year, four people in the same town died and five others had fallen ill after eating the same variety of pufferfish. In February 2009, a Malaysian fisherman died and four others were hospitalised after they consumed a meal of pufferfish when they ran out of food while at sea. In November 2011,

7592-411: The dominant forms of life. Although bacterial fossils exist, such as stromatolites , their lack of distinctive morphology prevents them from being used to examine the history of bacterial evolution, or to date the time of origin of a particular bacterial species. However, gene sequences can be used to reconstruct the bacterial phylogeny , and these studies indicate that bacteria diverged first from

7696-526: The elongated filaments of Actinomycetota species, the aggregates of Myxobacteria species, and the complex hyphae of Streptomyces species. These multicellular structures are often only seen in certain conditions. For example, when starved of amino acids, myxobacteria detect surrounding cells in a process known as quorum sensing , migrate towards each other, and aggregate to form fruiting bodies up to 500 micrometres long and containing approximately 100,000 bacterial cells. In these fruiting bodies,

7800-501: The energy released by the transfer of ions down an electrochemical gradient across the cell membrane. Fimbriae (sometimes called " attachment pili ") are fine filaments of protein, usually 2–10 nanometres in diameter and up to several micrometres in length. They are distributed over the surface of the cell, and resemble fine hairs when seen under the electron microscope . Fimbriae are believed to be involved in attachment to solid surfaces or to other cells, and are essential for

7904-597: The entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea. This involved the engulfment by proto-eukaryotic cells of alphaproteobacterial symbionts to form either mitochondria or hydrogenosomes , which are still found in all known Eukarya (sometimes in highly reduced form , e.g. in ancient "amitochondrial" protozoa). Later, some eukaryotes that already contained mitochondria also engulfed cyanobacteria -like organisms, leading to

8008-641: The evolution of different growth strategies (see r/K selection theory ). Some organisms can grow extremely rapidly when nutrients become available, such as the formation of algal and cyanobacterial blooms that often occur in lakes during the summer. Other organisms have adaptations to harsh environments, such as the production of multiple antibiotics by Streptomyces that inhibit the growth of competing microorganisms. In nature, many organisms live in communities (e.g., biofilms ) that may allow for increased supply of nutrients and protection from environmental stresses. These relationships can be essential for growth of

8112-450: The first life forms to appear on Earth , and are present in most of its habitats . Bacteria inhabit the air, soil, water, acidic hot springs , radioactive waste , and the deep biosphere of Earth's crust . Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the fixation of nitrogen from the atmosphere . The nutrient cycle includes the decomposition of dead bodies ; bacteria are responsible for

8216-653: The fish away from the bacteria that makes them poisonous. Since October 2012, restaurants in Japan have been permitted to sell fugu that has been prepared and packaged by a licensed practitioner elsewhere. China began issuing trial permits for serving fugu to restaurants in 2003. In 2016, the Chinese government abolished the permit system and allowed all restaurants to buy and serve farmed fish (without organs), now widely available. By 2019, such restaurants have become commonplace. China also allowed ordinary households to buy processed (organ-removed) whole fish online starting in 2017. The Saga Prefecture in Japan has petitioned

8320-409: The fish meat from being contaminated. The restaurant preparation of fugu is strictly controlled by law in Japan , Korea and several other countries, and only chefs who have qualified after three or more years of rigorous training are allowed to prepare the fish. Domestic preparation occasionally leads to accidental death. Throughout Japan, fugu is served as sashimi and nabemono . The liver

8424-566: The formation of chloroplasts in algae and plants. This is known as primary endosymbiosis . Bacteria are ubiquitous, living in every possible habitat on the planet including soil, underwater, deep in Earth's crust and even such extreme environments as acidic hot springs and radioactive waste. There are thought to be approximately 2×10 bacteria on Earth, forming a biomass that is only exceeded by plants. They are abundant in lakes and oceans, in arctic ice, and geothermal springs where they provide

8528-557: The general public. Since 1958, fugu chefs must earn a license to prepare and sell fugu to the public. This involves a two- or three-year apprenticeship. The licensing examination process consists of a written test, a fish-identification test, and a practical test, preparing and eating the fish. Only about 35 percent of the applicants pass. Small miscalculations result in failure or, in rare cases, death. Consumers believe that this training process makes it safer to eat fugu in restaurants or markets. Non-poisonous fugu can be produced by keeping

8632-563: The genus Spheroides , have also been consumed as a seafood delicacy, sometimes resulting in poisoning incidents. In South Korea , fugu is known as bok-eo (복어), the seafood delicacy is very popular in southern port cities such as Busan and Changwon . It is prepared in a number of ways resulting in a variety of dishes ranging from soups, raw fish and salads, all of which command a high price. Fugu Bulgogi and Jorim are popular in Daegu . Sale of fish belonging to this family (Tetraodontidae)

8736-453: The gut. However, several species of bacteria are pathogenic and cause infectious diseases , including cholera , syphilis , anthrax , leprosy , tuberculosis , tetanus and bubonic plague . The most common fatal bacterial diseases are respiratory infections . Antibiotics are used to treat bacterial infections and are also used in farming, making antibiotic resistance a growing problem. Bacteria are important in sewage treatment and

8840-409: The laboratory. The study of bacteria is known as bacteriology , a branch of microbiology . Like all animals, humans carry vast numbers (approximately 10 to 10 ) of bacteria. Most are in the gut , though there are many on the skin. Most of the bacteria in and on the body are harmless or rendered so by the protective effects of the immune system , and many are beneficial , particularly the ones in

8944-627: The largest viruses . Some bacteria may be even smaller, but these ultramicrobacteria are not well-studied. Shape . Most bacterial species are either spherical, called cocci ( singular coccus , from Greek kókkos , grain, seed), or rod-shaped, called bacilli ( sing . bacillus, from Latin baculus , stick). Some bacteria, called vibrio , are shaped like slightly curved rods or comma-shaped; others can be spiral-shaped, called spirilla , or tightly coiled, called spirochaetes . A small number of other unusual shapes have been described, such as star-shaped bacteria. This wide variety of shapes

9048-716: The light probably serves to attract fish or other large animals. Bacteria often function as multicellular aggregates known as biofilms , exchanging a variety of molecular signals for intercell communication and engaging in coordinated multicellular behaviour. The communal benefits of multicellular cooperation include a cellular division of labour , accessing resources that cannot effectively be used by single cells, collectively defending against antagonists, and optimising population survival by differentiating into distinct cell types. For example, bacteria in biofilms can have more than five hundred times increased resistance to antibacterial agents than individual "planktonic" bacteria of

9152-417: The newly formed daughter cells. Examples include fruiting body formation by myxobacteria and aerial hyphae formation by Streptomyces species, or budding. Budding involves a cell forming a protrusion that breaks away and produces a daughter cell. In the laboratory, bacteria are usually grown using solid or liquid media. Solid growth media , such as agar plates , are used to isolate pure cultures of

9256-473: The nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane , to energy. They live on and in plants and animals. Most do not cause diseases, are beneficial to their environments, and are essential for life. The soil is a rich source of bacteria and a few grams contain around a thousand million of them. They are all essential to soil ecology, breaking down toxic waste and recycling nutrients. They are even found in

9360-475: The outside of the cell membrane is the cell wall . Bacterial cell walls are made of peptidoglycan (also called murein), which is made from polysaccharide chains cross-linked by peptides containing D- amino acids . Bacterial cell walls are different from the cell walls of plants and fungi , which are made of cellulose and chitin , respectively. The cell wall of bacteria is also distinct from that of achaea, which do not contain peptidoglycan. The cell wall

9464-612: The production of the highly toxic forms of mercury ( methyl- and dimethylmercury ) in the environment. Nonrespiratory anaerobes use fermentation to generate energy and reducing power, secreting metabolic by-products (such as ethanol in brewing) as waste. Facultative anaerobes can switch between fermentation and different terminal electron acceptors depending on the environmental conditions in which they find themselves. Unlike in multicellular organisms, increases in cell size ( cell growth ) and reproduction by cell division are tightly linked in unicellular organisms. Bacteria grow to

9568-560: The replication of DNA or from exposure to mutagens . Mutation rates vary widely among different species of bacteria and even among different clones of a single species of bacteria. Genetic changes in bacterial genomes emerge from either random mutation during replication or "stress-directed mutation", where genes involved in a particular growth-limiting process have an increased mutation rate. Some bacteria transfer genetic material between cells. This can occur in three main ways. First, bacteria can take up exogenous DNA from their environment in

9672-491: The sale of which was prohibited by local ordinances at the time. Bandō claimed to be able to resist the poison, but died several hours after returning to his hotel. On August 23, 2007, a doctor in Thailand reported that unscrupulous fish sellers sold puffer meat disguised as salmon, which caused fifteen deaths over three years. About 115 people were taken to different hospitals. Fugu had been banned in Thailand five years prior to

9776-530: The same species. One type of intercellular communication by a molecular signal is called quorum sensing , which serves the purpose of determining whether the local population density is sufficient to support investment in processes that are only successful if large numbers of similar organisms behave similarly, such as excreting digestive enzymes or emitting light. Quorum sensing enables bacteria to coordinate gene expression and to produce, release, and detect autoinducers or pheromones that accumulate with

9880-563: The season and quality, as of 2022. The expense encourages chefs to slice the fish very carefully to obtain the largest possible amount of meat. A special knife, called fugu hiki , is usually stored separately from other knives. In China, packaged farmed fugu cost CN¥330 (US$ 50) per kilogram as of February 2023 . The symptoms of tetrodotoxin poisoning include dizziness, exhaustion, headache, nausea, or difficulty breathing. The person remains conscious but cannot speak or move. In high doses, breathing stops and asphyxiation follows. There

9984-452: The stew. Later, they met the beggar again and were delighted to see that he was still in good health. After that encounter, the beggar, who had hidden the stew instead of eating it, knew that it was safe and he could eat it. The three men had been fooled by the wise beggar. Lanterns can be made from the bodies of preserved fugu. These are occasionally seen outside of fugu restaurants, as children's toys, as folk art, or as souvenirs. Fugu skin

10088-412: The surfaces of plants, the majority of bacteria are bound to surfaces in biofilms. Biofilms are also important in medicine, as these structures are often present during chronic bacterial infections or in infections of implanted medical devices , and bacteria protected within biofilms are much harder to kill than individual isolated bacteria. The bacterial cell is surrounded by a cell membrane , which

10192-457: The terminal electron acceptor, while anaerobic organisms use other compounds such as nitrate , sulfate , or carbon dioxide. Many bacteria, called heterotrophs , derive their carbon from other organic carbon . Others, such as cyanobacteria and some purple bacteria , are autotrophic , meaning they obtain cellular carbon by fixing carbon dioxide . In unusual circumstances, the gas methane can be used by methanotrophic bacteria as both

10296-447: The transfer of antibiotic resistance. In such cases, gene acquisition from other bacteria or the environment is called horizontal gene transfer and may be common under natural conditions. Many bacteria are motile (able to move themselves) and do so using a variety of mechanisms. The best studied of these are flagella , long filaments that are turned by a motor at the base to generate propeller-like movement. The bacterial flagellum

10400-495: The virulence of some bacterial pathogens. Pili ( sing . pilus) are cellular appendages, slightly larger than fimbriae, that can transfer genetic material between bacterial cells in a process called conjugation where they are called conjugation pili or sex pili (see bacterial genetics, below). They can also generate movement where they are called type IV pili . Glycocalyx is produced by many bacteria to surround their cells, and varies in structural complexity: ranging from

10504-534: The writings of the polymath Shen Kuo as well as in the encyclopedic work Taiping Guangji . The scholar-statesman Su Shi famously remarked that the taste is worthy of death ( 值那一死 ). The torafugu , or tiger pufferfish ( Takifugu rubripes ), is the most prestigious edible species and the most poisonous. Other species are also eaten; for example, Higanfugu ( T. pardalis ), Shōsaifugu ( T. vermicularis syn. snyderi ), and Mafugu ( T. porphyreus ). The Ministry of Health, Labour and Welfare of Japan provides

10608-450: Was non-toxic, and it would allow for the safe preparation of fugu-kimo (puffer liver). Usuki , a town in Ōita Prefecture , has become known for selling non-poisonous fugu by 2008. Blowfish, specifically the obscure pufferfish and the torafugu, has been farmed in China since 1993 under the state-owned Tianzheng company. As of 2012 , most such fish is exported to Japan and South Korea, with

10712-509: Was served as a traditional dish named fugu-kimo , being widely thought to be a tasty part, but it is also the most poisonous, and serving this organ in restaurants was banned in Japan in 1984. In the gastronomic domains of East Asian cuisine, fugu has emerged as a highly renowned delicacy, garnering widespread acclaim in establishing itself as one of the most celebrated dishes in Japanese and Korean cuisine. Fugu has also been gradually emerging as

10816-656: Was sometimes sought out by individuals who wished to take their own lives. Much higher figures were reported in earlier years, peaking in 1958 when 176 people died from eating fugu in a single year. According to the Fugu Research Institute , 50% of the victims were poisoned by eating the liver, 43% from eating the ovaries, and 7% from eating the skin. One of the most famous victims was the Kabuki actor and " Living National Treasure " Bandō Mitsugorō VIII , who in 1975 died after eating four servings of fugu kimo (fugu liver),

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