72-474: The cantaloupe ( / ˈ k æ n t ə l oʊ p / KAN -tə-lohp ) is a type of true melon ( Cucumis melo ) with sweet, aromatic, and usually orange flesh. Originally, cantaloupe refers to the true cantaloupe or European cantaloupe with non- to slightly netted and often ribbed rind. Today, it also refers to the muskmelon with strongly netted rind, which is called cantaloupe in North America (hence
144-496: A Peoria, Illinois , market in 1943 was found to contain the highest yielding strain of mold for penicillin production, after a worldwide search. Raw cantaloupe is 90% water, 8% carbohydrates , 0.8% protein and 0.2% fat (table). In a reference amount of 100 grams (3.5 oz), raw cantaloupe supplies 140 kJ (34 kcal) of food energy , and is a rich source (20% or more of the Daily Value , DV) of vitamin A (29% DV) and
216-417: A serum sickness-like reaction in some individuals. Serum sickness is a type III hypersensitivity reaction that occurs one to three weeks after exposure to drugs including penicillin. It is not a true drug allergy, because allergies are type I hypersensitivity reactions, but repeated exposure to the offending agent can result in an anaphylactic reaction. Allergy will occur in 1–10% of people, presenting as
288-623: A different manner. The bacteria have thinner cell walls but the external surface is coated with an additional cell membrane, called the outer membrane. The outer membrane is a lipid layer ( lipopolysaccharide chain) that blocks passage of water-soluble ( hydrophilic ) molecules like penicillin. It thus acts as the first line of defence against any toxic substance, which is the reason for relative resistance to antibiotics compared to Gram-positive species. But penicillin can still enter Gram-negative species by diffusing through aqueous channels called porins (outer membrane proteins), which are dispersed among
360-439: A five-membered thiazolidine ring. The fusion of these two rings causes the β-lactam ring to be more reactive than monocyclic β-lactams because the two fused rings distort the β-lactam amide bond and therefore remove the resonance stabilisation normally found in these chemical bonds. An acyl side side chain attached to the β-lactam ring. A variety of β-lactam antibiotics have been produced following chemical modification from
432-479: A group of β-lactam antibiotics originally obtained from Penicillium moulds , principally P. chrysogenum and P. rubens . Most penicillins in clinical use are synthesised by P. chrysogenum using deep tank fermentation and then purified. A number of natural penicillins have been discovered, but only two purified compounds are in clinical use: penicillin G ( intramuscular or intravenous use ) and penicillin V (given by mouth). Penicillins were among
504-448: A known unit of penicillin: each glass vial was then filled with the number of units required. In the 1940s, a vial of 5,000 Oxford units was standard, but the depending on the batch, could contain anything from 15 mg to 20 mg of penicillin. Later, a vial of 1,000,000 international units became standard, and this could contain 2.5 g to 3 g of natural penicillin (a mixture of penicillin I, II, III, and IV and natural impurities). With
576-533: A moderate source of vitamin C (13% DV). Other micronutrients are in negligible amounts (less than 10% DV) (table). True melon Cucumis melo , also known as melon , is a species of Cucumis that has been developed into many cultivated varieties. The fruit is a pepo . The flesh is either sweet or bland, with or without an aroma, and the rind can be smooth (such as honeydew ), ribbed (such as European cantaloupe ), wrinkled (such as Cassaba melon), or netted (such as American cantaloupe ). The species
648-546: A result. However, the term had been in use long before that point. The true or European cantaloupe (Cantalupensis Group sensu stricto ), which has non- to slightly netted rind and orange flesh, includes the following types: The Israeli cantaloupe (Sub-group Ha'Ogen) is similar to the European one, but it has green flesh. The muskmelon or American cantaloupe (formerly Reticulatus Group but now merged into Cantalupensis Group), which has strongly netted rind and orange flesh, includes
720-527: A rich source (defined as at least 20% of daily value, or DV) of both vitamin A (68% DV) and vitamin C (61% DV). Other nutrients are at a negligible level. Melons are 90% water and 9% carbohydrates , with less than 1% each of protein and fat . In addition to their consumption when fresh, melons are sometimes dried . Other varieties are cooked, or grown for their seeds, which are processed to produce melon oil. Still other varieties are grown only for their pleasant fragrance. The Japanese liqueur Midori
792-523: A short half-life and is excreted via the kidneys. This means it must be dosed at least four times a day to maintain adequate levels of penicillin in the blood. Early manuals on the use of penicillin, therefore, recommended injections of penicillin as frequently as every three hours, and dosing penicillin has been described as being similar to trying to fill a bath with the plug out. This is no longer required since much larger doses of penicillin are cheaply and easily available; however, some authorities recommend
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#1732870056706864-408: A skin rash after exposure. IgE-mediated anaphylaxis will occur in approximately 0.01% of patients. Pain and inflammation at the injection site are also common for parenterally administered benzathine benzylpenicillin, benzylpenicillin, and, to a lesser extent, procaine benzylpenicillin. The condition is known as livedoid dermatitis or Nicolau syndrome. The term " penam " is used to describe
936-426: A synergistic effect with aminoglycosides , since the inhibition of peptidoglycan synthesis allows aminoglycosides to penetrate the bacterial cell wall more easily, allowing their disruption of bacterial protein synthesis within the cell. This results in a lowered MBC for susceptible organisms. Penicillins, like other β -lactam antibiotics, block not only the division of bacteria, including cyanobacteria , but also
1008-408: A useful precursor for manufacturing other penicillins. There are many semi-synthetic penicillins derived from 6-APA and these are in three groups: antistaphylococcal penicillins, broad-spectrum penicillins, and antipseudomonal penicillins. The semi-synthetic penicillins are all referred to as penicillins because they are all derived ultimately from penicillin G. The use of units to prescribe penicillin
1080-544: Is a different strain of S. aureus named methicillin-resistant S. aureus (MRSA) which is resistant not only to penicillin and other β-lactams, but also to most antibiotics. The bacterial strain developed after introduction of methicillin in 1959. In MRSA, mutations in the genes ( mec system) for PBP produce a variant protein called PBP2a (also termed PBP2'), while making four normal PBPs. PBP2a has poor binding affinity for penicillin and also lacks glycosyltransferase activity required for complete peptidoglycan synthesis (which
1152-535: Is a historical accident and is largely obsolete outside of the US. Since the original penicillin was an ill-defined mixture of active compounds (an amorphous yellow powder), the potency of each batch of penicillin varied from batch to batch. It was therefore impossible to prescribe 1 g of penicillin because the activity of 1 g of penicillin from one batch would be different from the activity from another batch. After manufacture, each batch of penicillin had to be standardised against
1224-578: Is an aminopenicillin that has never seen widespread clinical use. The Gram-negative species, Pseudomonas aeruginosa , is naturally resistant to many antibiotic classes. There were many efforts in the 1960s and 1970s to develop antibiotics that are active against Pseudomonas species. There are two chemical classes within the group: carboxypenicillins and ureidopenicillins. All are given by injection: none can be given by mouth. The term "penicillin", when used by itself, may refer to either of two chemical compounds , penicillin G or penicillin V. Penicillin G
1296-554: Is an ill-defined mixture of active components). The principal active components of Penicillium are listed in the following table: Other minor active components of Penicillium include penicillin O , penicillin U1, and penicillin U6. Other named constituents of natural Penicillium , such as penicillin A, were subsequently found not to have antibiotic activity and are not chemically related to antibiotic penicillins. The precise constitution of
1368-452: Is called "broad-spectrum" because they are active against a wide range of Gram-negative bacteria such as Escherichia coli and Salmonella typhi , for which penicillin is not suitable. However, resistance in these organisms is now common. There are many ampicillin precursors in existence. These are inactive compounds that are broken down in the gut to release ampicillin. None of these pro-drugs of ampicillin are in current use: Epicillin
1440-507: Is defined as the natural product of Penicillium mould with antimicrobial activity. It was coined by Alexander Fleming on 7 March 1929 when he discovered the antibacterial property of Penicillium rubens . Fleming explained in his 1929 paper in the British Journal of Experimental Pathology that "to avoid the repetition of the rather cumbersome phrase 'Mould broth filtrate', the name 'penicillin' will be used." The name thus refers to
1512-523: Is destroyed by stomach acid, so it cannot be taken by mouth, but doses as high as 2.4 g can be given (much higher than penicillin V). It is given by intravenous or intramuscular injection. It can be formulated as an insoluble salt, and there are two such formulations in current use: procaine penicillin and benzathine benzylpenicillin . When a high concentration in the blood must be maintained, penicillin G must be administered at relatively frequent intervals, because it
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#17328700567061584-709: Is due to changes in the cell wall. For example, resistance to vancomycin in S. aureus is due to additional peptidoglycan synthesis that makes the cell wall much thicker preventing effective penicillin entry. Resistance in Gram-negative bacteria is due to mutational variations in the structure and number of porins. In bacteria like Pseudomonas aeruginosa , there is reduced number of porins; whereas in bacteria like Enterobacter species, Escherichia coli and Klebsiella pneumoniae , there are modified porins such as non-specific porins (such as OmpC and OmpF groups) that cannot transport penicillin. Resistance due to PBP alterations
1656-628: Is eliminated quite rapidly from the bloodstream by the kidney. Penicillin G is licensed for use to treat septicaemia , empyema , pneumonia , pericarditis , endocarditis and meningitis caused by susceptible strains of staphylococci and streptococci. It is also licensed for the treatment of anthrax , actinomycosis , cervicofacial disease, thoracic and abdominal disease, clostridial infections , botulism , gas gangrene (with accompanying debridement and/or surgery as indicated), tetanus (as an adjunctive therapy to human tetanus immune globulin), diphtheria (as an adjunctive therapy to antitoxin and for
1728-582: Is flavored with melon. There is debate among scholars whether the abattiach in The Book of Numbers 11:5 refers to a melon or a watermelon . Both types of melon were known in Ancient Egypt and other settled areas. Some botanists consider melons native to the Levant and Egypt, while others n Persia , India or Central Asia, thus the origin is uncertain. Researchers have shown that seeds and rootstocks were among
1800-513: Is highly varied. A common case is found in Streptococcus pneumoniae where there is mutation in the gene for PBP, and the mutant PBPs have decreased binding affinity for penicillins. There are six mutant PBPs in S. pneumoniae , of which PBP1a, PBP2b, PBP2x and sometimes PBP2a are responsible for reduced binding affinity. S. aureus can activate a hidden gene that produces a different PBP, PBD2, which has low binding affinity for penicillins. There
1872-431: Is relatively resistant to stomach acid. Doses higher than 500 mg are not fully effective because of poor absorption. It is used for the same bacterial infections as those of penicillin G and is the most widely used form of penicillin. However, it is not used for diseases, such as endocarditis , where high blood levels of penicillin are required. Because penicillin resistance is now so common, other antibiotics are now
1944-565: Is rich in nutrients, but are vulnerable to downy mildew and anthracnose . Disease risk is reduced by crop rotation with non- cucurbit crops, avoiding crops susceptible to similar diseases as melons. Cross pollination has resulted in some varieties developing resistance to powdery mildew . Insects attracted to melons include the cucumber beetle , melon aphid , melonworm moth and the pickleworm . Melons are monoecious or andromonoecious plants. They do not cross with watermelon , cucumber , pumpkin , or squash , but varieties within
2016-405: Is sometimes referred to as muskmelon , but there is no consensus about the usage of this term, as it can also be used as a specific name for the musky netted-rind American cantaloupe, or as a generic name for any sweet-flesh variety such the inodorous smooth-rind honeydew melon. The origin of melons is not known. Research has revealed that seeds and rootstocks were among the goods traded along
2088-439: Is the R substituent . This side chain is connected to the 6-aminopenicillanic acid residue and results in variations in the antimicrobial spectrum, stability, and susceptibility to beta-lactamases of each type. Penicillin G (benzylpenicillin) was first produced from a penicillium fungus that occurs in nature. The strain of fungus used today for the manufacture of penicillin G was created by genetic engineering to improve
2160-547: Is the name for the form that grows in Suriname which, because of its thick skin and little flesh, is less consumed." A common etymology involves the Spanish-born Juana María de los Dolores de León Smith , who ate canteloupe for breakfast while her husband and 19th-century governor of Cape Colony , Sir Harry Smith , ate bacon and eggs; the fruit was termed Spanish bacon ( Afrikaans Spaanse spek ) by locals as
2232-408: Is thus ineffective for Gram-negative bacteria. The size and number of porins are different in different bacteria. As a result of the two factors—size of penicillin and porin—Gram-negative bacteria can be unsusceptible or have varying degree of susceptibility to specific penicillin. Penicillin kills bacteria by inhibiting the completion of the synthesis of peptidoglycans , the structural component of
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2304-409: The bacterial cell wall . It specifically inhibits the activity of enzymes that are needed for the cross-linking of peptidoglycans during the final step in cell wall biosynthesis. It does this by binding to penicillin binding proteins with the β-lactam ring, a structure found on penicillin molecules. This causes the cell wall to weaken due to fewer cross-links and means water uncontrollably flows into
2376-485: The immunoglobulin E (IgE) cross-reactivity is only 3%. Penicillin was discovered in 1928 by Scottish scientist Alexander Fleming as a crude extract of P. rubens . Fleming's student Cecil George Paine was the first to successfully use penicillin to treat eye infection ( neonatal conjunctivitis ) in 1930. The purified compound (penicillin F) was isolated in 1940 by a research team led by Howard Florey and Ernst Boris Chain at
2448-484: The 6-APA structure during synthesis, specifically by making chemical substitutions in the acyl side chain. For example, the first chemically altered penicillin, methicillin, had substitutions by methoxy groups at positions 2’ and 6’ of the 6-APA benzene ring from penicillin G. This difference makes methicillin resistant to the activity of β-lactamase , an enzyme by which many bacteria are naturally unsusceptible to penicillins. Penicillin can easily enter bacterial cells in
2520-875: The Armenian cucumber and Serpent cucumber, is a non-sweet melon found throughout Asia from Turkey to Japan. It is similar to a cucumber in taste and appearance. Outside Asia, snake melons are grown in the United States, Italy, Sudan and parts of North Africa, including Egypt. The snake melon is more popular in Arab countries. Other varieties grown in Africa are bitter, cultivated for their edible seeds. For commercially grown varieties certain features like protective hard netting and firm flesh are preferred for purposes of shipping and other requirements of commercial markets. Per 100 gram serving, cantaloupe melons provide 34 calories and are
2592-482: The Japanese muskmelon under Inodorus Group instead of Cantalupensis or Reticulatus Group. In 2016, global production of melons, including cantaloupes, totaled 31.2 million tons , with China accounting for 51% of the world total (15.9 million tons). Other significant countries growing cantaloupe were Turkey , Iran , Egypt , and India producing 1 to 1.9 million tons, respectively. California grows 75% of
2664-532: The University of Oxford. Fleming first used the purified penicillin to treat streptococcal meningitis in 1942. The 1945 Nobel Prize in Physiology or Medicine was shared by Chain, Fleming, and Florey. Several semisynthetic penicillins are effective against a broader spectrum of bacteria: these include the antistaphylococcal penicillins , aminopenicillins , and antipseudomonal penicillins . The term "penicillin"
2736-477: The advent of pure penicillin G preparations (a white crystalline powder), there is little reason to prescribe penicillin in units. The "unit" of penicillin has had three previous definitions, and each definition was chosen as being roughly equivalent to the previous one. There is an older unit for penicillin V that is not equivalent to the current penicillin V unit. The reason is that the US FDA incorrectly assumed that
2808-404: The antibiotic. They named the enzyme penicillinase . Penicillinase is now classified as member of enzymes called β-lactamases. These β-lactamases are naturally present in many other bacteria, and many bacteria produce them upon constant exposure to antibiotics. In most bacteria, resistance can be through three different mechanisms – reduced permeability in bacteria, reduced binding affinity of
2880-426: The bacteria resistant to penicillin. Therefore, some penicillins are modified or given with other drugs for use against antibiotic-resistant bacteria or in immunocompromised patients. The use of clavulanic acid or tazobactam, β-lactamase inhibitors, alongside penicillin gives penicillin activity against β-lactamase-producing bacteria. β-Lactamase inhibitors irreversibly bind to β-lactamase preventing it from breaking down
2952-408: The basic structure of penicillins. It is made up of an enclosed dipeptide formed by the condensation of L -cysteine and D -valine . This results in the formations of β-lactam and thiazolidinic rings. The key structural feature of the penicillins is the four-membered β-lactam ring; this structural moiety is essential for penicillin's antibacterial activity. The β-lactam ring is itself fused to
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3024-482: The beta-lactam rings on the antibiotic molecule. Alternatively, flucloxacillin is a modified penicillin that has activity against β-lactamase-producing bacteria due to an acyl side chain that protects the beta-lactam ring from β-lactamase. Penicillin has low protein binding in plasma. The bioavailability of penicillin depends on the type: penicillin G has low bioavailability, below 30%, whereas penicillin V has higher bioavailability, between 60 and 70%. Penicillin has
3096-532: The cantaloupes in the US. Cantaloupe is normally eaten as a fresh fruit, as a salad, or as a dessert with ice cream or custard. Melon pieces wrapped in prosciutto are a familiar antipasto . The seeds are edible and may be dried for use as a snack. Because the surface of a cantaloupe can contain harmful bacteria—in particular, Salmonella —it is recommended that a melon be washed and scrubbed thoroughly before cutting and consumption to prevent risk of Salmonella or other bacterial pathogens. A moldy cantaloupe in
3168-608: The caravan routes of the Ancient World. Some botanists consider melons native to the Levant and Egypt, while others place their origin in Iran, India or Central Asia. Still others support an African origin, and in modern times wild melons can still be found in some African countries. The melon is an annual , trailing herb. It grows well in subtropical or warm, temperate climates. Melons prefer warm, well-fertilized soil with good drainage that
3240-470: The case of Gram-positive species . This is because Gram-positive bacteria do not have an outer cell membrane and are simply enclosed in a thick cell wall . Penicillin molecules are small enough to pass through the spaces of glycoproteins in the cell wall. For this reason Gram-positive bacteria are very susceptible to penicillin (as first evidenced by the discovery of penicillin in 1928 ). Penicillin, or any other molecule, enters Gram-negative bacteria in
3312-402: The cell because it cannot maintain the correct osmotic gradient. This results in cell lysis and death. Bacteria constantly remodel their peptidoglycan cell walls, simultaneously building and breaking down portions of the cell wall as they grow and divide. During the last stages of peptidoglycan biosynthesis, uridine diphosphate- N -acetylmuramic acid pentapeptide (UDP-MurNAc) is formed in which
3384-402: The cell wall of the bacterium, and osmotic pressure becomes increasingly uncompensated—eventually causing cell death ( cytolysis ). In addition, the build-up of peptidoglycan precursors triggers the activation of bacterial cell wall hydrolases and autolysins, which further digest the cell wall's peptidoglycans. The small size of the penicillins increases their potency, by allowing them to penetrate
3456-407: The common core skeleton of a member of the penicillins. This core has the molecular formula R-C 9 H 11 N 2 O 4 S, where R is the variable side chain that differentiates the penicillins from one another. The penam core has a molar mass of 243 g/mol, with larger penicillins having molar mass near 450—for example, cloxacillin has a molar mass of 436 g/mol. 6-APA (C 8 H 12 N 2 O 3 S) forms
3528-427: The division of cyanelles, the photosynthetic organelles of the glaucophytes , and the division of chloroplasts of bryophytes . In contrast, they have no effect on the plastids of the highly developed vascular plants . This supports the endosymbiotic theory of the evolution of plastid division in land plants. Some bacteria produce enzymes that break down the β-lactam ring, called β-lactamases , which make
3600-401: The entire depth of the cell wall. This is in contrast to the glycopeptide antibiotics vancomycin and teicoplanin , which are both much larger than the penicillins. Gram-positive bacteria are called protoplasts when they lose their cell walls. Gram-negative bacteria do not lose their cell walls completely and are called spheroplasts after treatment with penicillin. Penicillin shows
3672-439: The fatty molecules and can transport nutrients and antibiotics into the bacteria. Porins are large enough to allow diffusion of most penicillins, but the rate of diffusion through them is determined by the specific size of the drug molecules. For instance, penicillin G is large and enters through porins slowly; while smaller ampicillin and amoxicillin diffuse much faster. In contrast, large vancomycin can not pass through porins and
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#17328700567063744-614: The first medications to be effective against many bacterial infections caused by staphylococci and streptococci . They are still widely used today for various bacterial infections, though many types of bacteria have developed resistance following extensive use. Ten percent of the population claims penicillin allergies , but because the frequency of positive skin test results decreases by 10% with each year of avoidance, 90% of these patients can eventually tolerate penicillin. Additionally, those with penicillin allergies can usually tolerate cephalosporins (another group of β-lactam) because
3816-466: The following types: A melon with netted rind is not necessarily a cantaloupe. Many varieties of Chandalak Group and Ameri Group also have netted rind. The Japanese muskmelon (Sub-group Earl's) resembles the American cantaloupe in netted rind, but differs in green flesh and non-dehiscent peduncles (which means the melon does not detach from the stalk when it is ripe). Therefore, some horticulturists classify
3888-471: The four-membered β-lactam ring of penicillin instead of UDP-MurNAc. As a consequence, DD -transpeptidase is inactivated, the formation of cross-links between UDP-MurNAc and N -acetyl glucosamine is blocked so that an imbalance between cell wall production and degradation develops, causing the cell to rapidly die. The enzymes that hydrolyze the peptidoglycan cross-links continue to function, even while those that form such cross-links do not. This weakens
3960-579: The fourth and fifth amino acids are both D -alanyl- D -alanine. The transfer of D -alanine is done (catalysed) by the enzyme DD -transpeptidase ( penicillin-binding proteins are such type). The structural integrity of bacterial cell wall depends on the cross linking of UDP-MurNAc and N -acetyl glucosamine. Penicillin and other β-lactam antibiotics act as an analogue of D -alanine- D -alanine (the dipeptide) in UDP-MurNAc owing to conformational similarities. The DD -transpeptidase then binds
4032-770: The goods traded along the caravan routes of the Ancient World. Several scientists support an African origin, and in modern times wild melons can still be found in several African countries in East Africa like Ethiopia, Somalia and Tanzania. Melon was domesticated in West Asia and over time many cultivars developed with variety in shape and sweetness. Iran, India, Uzbekistan, Afghanistan and China become centers for melon production. Melons were consumed in Ancient Greece and Rome. Penicillin Penicillins ( P , PCN or PEN ) are
4104-521: The infecting strain is known to be susceptible. Common (≥ 1% of people) adverse drug reactions associated with use of the penicillins include diarrhoea , hypersensitivity , nausea , rash , neurotoxicity , urticaria , and superinfection (including candidiasis ). Infrequent adverse effects (0.1–1% of people) include fever , vomiting , erythema , dermatitis , angioedema , seizures (especially in people with epilepsy ), and pseudomembranous colitis . Penicillin can also induce serum sickness or
4176-532: The name American cantaloupe ), rockmelon in Australia and New Zealand, and spanspek in Southern Africa. Cantaloupes range in mass from 0.5 to 5 kilograms (1 to 11 lb). The name cantaloupe was derived in the 18th century via French cantaloup from The Cantus Region of Italian Cantalupo , which was formerly a papal county seat near Rome, after the fruit was introduced there from Armenia . It
4248-496: The penicillin extracted depends on the species of Penicillium mould used and on the nutrient media used to culture the mould. Fleming's original strain of Penicillium rubens produces principally penicillin F, named after Fleming. But penicillin F is unstable, difficult to isolate, and produced by the mould in small quantities. The principal commercial strain of Penicillium chrysogenum (the Peoria strain) produces penicillin G as
4320-479: The penicillin-binding proteins (PBPs) or destruction of the antibiotic through the expression of β-lactamase. Using any of these, bacteria commonly develop resistance to different antibiotics, a phenomenon called multi-drug resistance . The actual process of resistance mechanism can be very complex. In case of reduced permeability in bacteria, the mechanisms are different between Gram-positive and Gram-negative bacteria. In Gram-positive bacteria, blockage of penicillin
4392-469: The penicillins. They are synthesised by adding various side-chains to the precursor 6-APA , which is isolated from penicillin G. These are the antistaphylococcal antibiotics, broad-spectrum antibiotics, and antipseudomonal antibiotics. Antistaphylococcal antibiotics are so-called because they are resistant to being broken down by staphylococcal penicillinase . They are also, therefore, referred to as being penicillinase-resistant. This group of antibiotics
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#17328700567064464-452: The plant Digitalis . In modern usage, the term penicillin is used more broadly to refer to any β-lactam antimicrobial that contains a thiazolidine ring fused to the β-lactam core and may or may not be a natural product. Like most natural products, penicillin is present in Penicillium moulds as a mixture of active constituents ( gentamicin is another example of a natural product that
4536-430: The potency of penicillin V is the same mole-for-mole as penicillin G. In fact, penicillin V is less potent than penicillin G, and the current penicillin V unit reflects that fact. A similar standard was also established for penicillin K. Penicillins consist of a distinct 4-membered beta-lactam ring, in addition to a thiazolide ring and an R side chain. The main distinguishing feature between variants within this family
4608-468: The preferred choice for treatments. For example, penicillin used to be the first-line treatment for infections with Neisseria gonorrhoeae and Neisseria meningitidis , but it is no longer recommended for treatment of these infections. Penicillin resistance is now very common in Staphylococcus aureus , which means penicillin should not be used to treat infections caused by S. aureus infection unless
4680-515: The prevention of the carrier state), erysipelothrix endocarditis, fusospirochetosis (severe infections of the oropharynx, lower respiratory tract and genital area), Listeria infections, meningitis, endocarditis, Pasteurella infections including bacteraemia and meningitis, Haverhill fever ; rat-bite fever and disseminated gonococcal infections , meningococcal meningitis and/or septicaemia caused by penicillin-susceptible organisms and syphilis. Penicillin V can be taken by mouth because it
4752-401: The principal component when corn steep liquor is used as the culture medium. When phenoxyethanol or phenoxyacetic acid are added to the culture medium, the mould produces penicillin V as the main penicillin instead. 6-Aminopenicillanic acid (6-APA) is a compound derived from penicillin G. 6-APA contains the beta-lactam core of penicillin G, but with the side chains stripped off; 6-APA is
4824-401: The scientific name of the mould, as described by Fleming in his Nobel lecture in 1945: I have been frequently asked why I invented the name "Penicillin". I simply followed perfectly orthodox lines and coined a word which explained that the substance penicillin was derived from a plant of the genus Penicillium just as many years ago the word " Digitalin " was invented for a substance derived from
4896-449: The species intercross frequently. The genome of Cucumis melo was first sequenced in 2012. Some authors treat C. melo as having two subspecies, C. melo agrestis and C. melo melo . Variants within these subspecies fall into groups whose genetics largely agree with their phenotypic traits, such as disease resistance, rind texture, flesh color, and fruit shape. Variants or landraces (some of which were originally classified as species; see
4968-506: The synonyms list to the right) include C. melo var. acidulus (Mangalore melon), adana , agrestis (wild melon), ameri (summer melon), cantalupensis ( cantaloupe ), reticulatus ( muskmelon ), chandalak , chate , chito , conomon ( Oriental pickling melon ), dudaim (pocket melon), flexuosus ( snake melon ), inodorus (winter melon), momordica (snap melon), tibish , chinensis and makuwa ( Oriental melon ). Not all varieties are sweet melons. The snake melon , also called
5040-511: The use of continuous penicillin infusions for this reason. When Alexander Fleming discovered the crude penicillin in 1928, one important observation he made was that many bacteria were not affected by penicillin. This phenomenon was realised by Ernst Chain and Edward Abraham while trying to identify the exact of penicillin. In 1940, they discovered that unsusceptible bacteria like Escherichia coli produced specific enzymes that can break down penicillin molecules, thus making them resistant to
5112-415: The yield in the manufacturing process. None of the other natural penicillins (F, K, N, X, O, U1 or U6) are currently in clinical use. Penicillin V (phenoxymethylpenicillin) is produced by adding the precursor phenoxyacetic acid to the medium in which a genetically modified strain of the penicillium fungus is being cultured. There are three major groups of other semi-synthetic antibiotics related to
5184-701: Was first mentioned in English literature in 1739. The cantaloupe most likely originated in a region from South Asia to Africa. It was later introduced to Europe, and around 1890, became a commercial crop in the United States. Melon derived from use in Old French as meloun during the 13th century, and from Medieval Latin melonem , a kind of pumpkin. It was among the first plants to be domesticated and cultivated . The South African English name spanspek dates back at least as far as 18th-century Dutch Suriname : J. van Donselaar wrote in 1770, " Spaansch-spek
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