instance_of thioglycolate broth
Fermentation is a metabolic process that converts sugar to acids , gases , or alcohol . It occurs in yeast and ___MASK69___ , and also in oxygen - starved muscle cells , as in the case of lactic acid fermentation . Fermentation is also used more broadly to refer to the bulk growth of microorganisms on a ___MASK35___ , often with the goal of producing a specific chemical product . French microbiologist Louis Pasteur is often remembered for his insights into fermentation and its microbial causes . The science of fermentation is known as zymology . A ___MASK99___ ( genera ) is a taxonomic rank used in the ___MASK92___ of living and fossil organisms in biology . In the ___MASK55___ of ___MASK92___ , ___MASK99___ comes above species and below family . In binomial nomenclature , the ___MASK99___ name forms the first part of the binomial species name for each species within the ___MASK99___ . An endospore is a dormant , tough , and non - reproductive ___MASK59___ produced by certain bacteria from the Firmicute phylum . The name " endospore " is suggestive of a spore or seed - like form (" endo " means within ), but it is not a true spore ( i . e ., not an ___MASK32___ ). It is a stripped - down , dormant form to which the bacterium can reduce itself . Endospore ___MASK30___ is usually triggered by a lack of nutrients , and usually occurs in gram - positive bacteria . In endospore ___MASK30___ , the bacterium divides within its cell ___MASK4___ . One side then engulfs the other . Endospores enable bacteria to lie dormant for extended periods , even centuries . Revival of spores millions of years old has been claimed . When the environment becomes more favorable , the endospore can reactivate itself to the vegetative state . Most types of bacteria cannot change to the endospore form . Examples of bacteria that can form endospores include " Bacillus " and " Clostridium ". Clostridium is a ___MASK99___ of Gram - positive bacteria , which includes several significant human pathogens , including the causative agent of botulism and an important cause of diarrhea , " Clostridium difficile ". They are obligate anaerobes capable of producing endospores . The normal , reproducing cells of " Clostridium ", called the vegetative form , are rod - shaped , which gives them their name , from the Greek  or spindle . " Clostridium " endospores have a distinct bowling pin or bottle shape , distinguishing them from other bacterial endospores , which are usually ovoid in shape . " Clostridium " species inhabit soils and the intestinal tract of animals , including humans . " Clostridium " is a normal inhabitant of the healthy lower reproductive tract of women . Botulism is a rare and potentially fatal ___MASK15___ caused by a toxin , produced by the bacterium " Clostridium botulinum ". The disease begins with weakness , trouble seeing , feeling tired , and trouble speaking . This ___MASK61___ then be followed by weakness of the arms , chest muscles , and legs . The disease does not usually affect consciousness or cause a fever . Botulism can be spread several different ways . The bacterial spores which cause it are common in both ___MASK8___ and ___MASK16___ . They produce the botulinum toxin when exposed to low oxygen levels and certain temperatures . Foodborne botulism happens when food containing the toxin is eaten . Infant botulism happens when the bacteria develops in the intestines and releases the toxin . This typically only occurs in children less than six months old , as protective mechanisms develop after that ___MASK42___ . Wound botulism is found most often among those who inject street drugs . In this situation , spores enter a wound , and in the absence of oxygen , release the toxin . It is not passed directly between people . The diagnosis is confirmed by finding the toxin or bacteria in the person in question . Prevention is primarily by proper food preparation . The toxin , though not the ___MASK23___ , is destroyed by heating it to more than for longer than 5 minutes . Honey can contain the ___MASK23___ , and for this reason , honey should not be fed to children under 12 months . Treatment is with an antitoxin . In those who lose their ability to breathe on their own , mechanical ventilation ___MASK61___ be necessary for months . Antibiotics ___MASK61___ be used for wound botulism . Death occurs in 5 to 10 % of people . Botulism can affect many other animals . The word is from Latin , " botulus ", meaning sausage . Early descriptions of botulism date from at least as far back as 1793 in Germany . An obligate aerobe is an ___MASK23___ that requires oxygen to grow . Through cellular respiration , these organisms use oxygen to metabolise substances , like sugars or fats , to obtain energy . In this type of respiration , oxygen serves as the terminal electron acceptor for the electron transport chain . Aerobic respiration has the advantage of yielding more energy ( adenosine triphosphate or ATP ) than fermentation or anaerobic respiration , but obligate aerobes are subject to high levels of oxidative stress . Thioglycolate broth is a multi - purpose , enriched differential medium used primarily to determine the oxygen requirements of microorganisms . Sodium thioglycolate in the medium consumes oxygen and permits the growth of obligate anaerobes . This , combined with the diffusion of oxygen from the top of the broth produces a range of oxygen concentrations in the media along its depth . The oxygen concentration at a given level is indicated by a redox sensitive dye like resazurine that turns pink in the presence of oxygen . This allows the differentiation of obligate aerobes , obligate anaerobes , facultative anaerobes , microaerophiles , and aerotolerant organisms . For example , obligately anaerobic Clostridium ___MASK44___ will be seen growing only in the bottom of the test tube . Thioglycolate broth is also used to recruit macrophages to the peritoneal cavity of mice when injected intraperitoneally . It recruits numerous macrophages , but does not activate them . Obligate anaerobes are microorganisms killed by normal atmospheric concentrations of oxygen ( 20 . 95 % O ). Oxygen tolerance varies between ___MASK44___ , some capable of surviving in up to 8 % oxygen , others losing viability unless the oxygen concentration is less than 0 . 5 %. An important distinction needs to be made here between the obligate anaerobes and the microaerophiles . Microaerophiles , like the obligate anaerobes , are damaged by normal atmospheric concentrations of oxygen . However , microaerophiles metabolise ___MASK34___ aerobically , and obligate anaerobes metabolise ___MASK34___ anaerobically . Microaerophiles therefore require oxygen ( typically 2  10 % O ) for growth . Obligate anaerobes do not . Gram - positive ___MASK69___ are ___MASK69___ that give a positive ___MASK85___ in the Gram ___MASK83___ test . Gram - positive ___MASK69___ take up the crystal violet ___MASK83___ used in the test , and then appear to be purple - coloured when seen through a microscope . This is because the thick peptidoglycan layer in the bacterial cell ___MASK4___ retains the ___MASK83___ after it is washed away from the rest of the sample , in the decolorization stage of the test .