Oxygen Relationship of Organisms

<div class="separator" style="clear: both; text-align: center;"> <a href="https://4.bp.blogspot.com/-dS3DpowDN-U/WB88ihD0hNI/AAAAAAAAApo/HJYob1ELHf4LQQVcfsowkRg7HI2ybccuwCLcB/s1600/oxysen%2Brelation%2Bof%2Borganisms.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="300" src="https://4.bp.blogspot.com/-dS3DpowDN-U/WB88ihD0hNI/AAAAAAAAApo/HJYob1ELHf4LQQVcfsowkRg7HI2ybccuwCLcB/s400/oxysen%2Brelation%2Bof%2Borganisms.jpg" width="400" /></a></div> <div class="MsoNormal"> <span style="font-size: 14.0pt; line-height: 115%;"><br /></span></div> <div class="MsoNormal"> <span style="font-size: 14.0pt; line-height: 115%;">Although oxygen is an essential compound in life, excess oxygen becomes toxic to the organisms. Oxygen is a one of strong oxidation agent in the word. Oxidation of oxygen is able to produce highly toxic forms of oxygen like super oxide and hydroxyl. They kill the living cell oxidizing chemicals in the cell.<o:p></o:p></span></div> <div class="MsoNormal"> <span style="font-size: 14.0pt; line-height: 115%;"><br /></span></div> <div class="MsoNormal"> <span style="font-size: 14.0pt; line-height: 115%;">                       In human excess oxygen is not a serious problem because oxygen is transported into cells by the blood.  Pigments in the human blood, hemoglobin is mainly responsible for oxygen transportation. It is only have ability to transport 4 oxygen molecules once so cells do not experience high concentrations of oxygen. But single celled tiny microorganisms always exposure to the environment and oxygen go through their cell. Some organisms have enzymes those are able to destroy the toxic forms of oxygen.  The enzymes are <b>catalase, peroxidase and super oxide dismutase</b>. So they can live under even high concentration of oxygen due to the presence of those enzymes. They are unable to live under anaerobic conditions.  So they refer to as <b>aerobic organisms</b>. They can only perform aerobic respiration to produce ATP. <o:p></o:p></span></div> <div class="MsoNormal"> <span style="font-size: 14.0pt; line-height: 115%;">                       Some of microorganisms are unable to live in aerobic environment due to the absence of above enzymes. So they have to remain in anaerobic environment like deep mud layer in sea and intestine of animals. Those organisms refer to as <b>anaerobic microorganisms</b>. They perform both fermentation and aerobic respiration for their ATP production. They use inorganic substances like ferrous, nitrate and sulfate as their terminal electron acceptor in their electron transport chain instead of oxygen in anaerobic respiration.  Some microorganisms can perform both mechanisms to synthesis ATP while some only perform fermentation due to the absence of electron transport chain. Those who can perform both prefer anaerobic respiration than fermentation because efficiency and number of ATP synthesis of anaerobic respiration is higher than that of fermentation. When there is no terminal electron acceptor is available they perform fermentation. <o:p></o:p></span></div> <div class="MsoNormal"> <span style="font-size: 14.0pt; line-height: 115%;"><br /></span></div> <div class="MsoNormal"> <span style="font-size: 14.0pt; line-height: 115%;">                       Another group of microorganisms are able to live under both aerobic and anaerobic conditions. Because they have enzymes to destroy the toxic forms of oxygen so they can live in aerobic environment. They can perform fermentation and/or anaerobic respiration under anaerobic condition so they are able to live under even anaerobic conditions.  Those microorganisms refer to as facultative microorganisms. <i>Thiobacillus dentrificans</i> is a <b>facultative microorganism</b>. It performs aerobic respiration to produce ATP under aerobic conditions.  If the environment suddenly becomes anaerobic, they shift into anaerobic respiration. They use nitrate ion in the soil as their terminal electron acceptor.  So it convert nitrate into atmospheric nitrogen. It cause releasing nitrogen from the soil and decrease the soil fertility. If aeration is return, then again they start to perform aerobic respiration because efficiency and number of ATP synthesis of aerobic respiration is little bit higher than that of anaerobic respiration.  <i>Escherichia coli</i> are another example for facultative microorganisms. It lives in the human intestine where the conditions are anaerobic. So they perform anaerobic respiration for their ATP production. Somehow they enter into free environment through the human faces.  They can survive 2-3 days in the free environment and produce ATP aid in aerobic respirations. <o:p></o:p></span></div> <div class="MsoNormal"> <span style="font-size: 14.0pt; line-height: 115%;"><br /></span></div> <br /> <div class="MsoNormal"> <span style="font-size: 14.0pt; line-height: 115%;">                       Some microorganisms are able to live under little concentration of oxygen. They refer to as <b>microaerophiles</b>. They have little amount of enzymes those destroy the toxic forms of oxygen or not. So if the environment suddenly becomes highly oxygenated, they form spores in order to survive. Spores are a domal structure. Metabolic actives do not happen within it. The tick wall of spores is not allowed oxygen to penetrate through it.  If they suddenly fallen into environment with anaerobic condition like deep wound in animals or oxygen concentration become vanish, they become active again. Clostridum is an example for microaerophiles.<o:p></o:p></span></div> <script> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','https://www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-65880709-1', 'auto'); ga('send', 'pageview'); </script>

Oxygen Relationship of Organisms

Although oxygen is an essential compound in life, excess oxygen becomes toxic to the organisms. Oxygen is a one of strong oxidation age...

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Winogradsky Column

<div class="separator" style="clear: both; text-align: center;"> <a href="https://4.bp.blogspot.com/--GvjxOUnBLQ/WB7IG03IjOI/AAAAAAAAApQ/WuQT9uN90rIsrXgMkyFNNvx-J27Y-CLagCLcB/s1600/winogradsky%2Bcoumn.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="293" src="https://4.bp.blogspot.com/--GvjxOUnBLQ/WB7IG03IjOI/AAAAAAAAApQ/WuQT9uN90rIsrXgMkyFNNvx-J27Y-CLagCLcB/s400/winogradsky%2Bcoumn.png" width="400" /></a></div> <div class="MsoNormal"> <br /></div> <div class="MsoNormal"> <br /></div> <div class="MsoNormal"> Freshwater sample extracted from a pond is taken into a glass cylinder. As it is made of glass, light is able to penetrate through it. It is kept for few weeks further observations. After few weeks, a mud layer deposit at the bottom of the cylinder. As a result of microbial activities, separation of layers in the water column can be seen.<o:p></o:p></div> <div class="MsoNormal">                                                               At the beginning, aerobic respiratory organisms are taken place. They consume the large amount of organic matter present in the bottom mud layer. As they use oxygen as their terminal electron acceptor in their electro transport chains, oxygen in the mud layer is depleted. Then fermentative microorganisms become active. <i>Clostridium</i> is the one of fermentative bacteria that is active in the mud under anaerobic conditions. They use as cellulose as their substrate and produce alcohols, acids and aldehydes as their byproducts. After that anaerobic microorganisms are active. They use fermentative byproducts as their substrate in the anaerobic respirations. They use sulfate as their terminal electron acceptor in their electro transport chains. So they convert sulfate ions into hydrogen sulfide. Hydrogen sulfide reacts with iron (II) in the mud. As a result of this reaction ferrous sulfide is produced. It gives a black to the mud. Since Hydrogen sulfide is gas, it moves upward of the water column. <o:p></o:p></div> <div class="MsoNormal">                                                               Green sulfur bacteria live in the layer just above the mud. They are shown in green color due to the color of photosynthetic pigments.  The method of ATP synthase of them is photosynthesis. As the light penetrates through the water column, they are able to do photosynthesis. They use hydrogen sulfide as their electro donor to fulfill the electro deficiency in the chlorophyll. So oxidation of hydrogen sulfide give an electron the chlorophyll and convert into sulfur.  Sulfur is deposited in their cells. Reaming hydrogen sulfide moves further upward.<o:p></o:p></div> <div class="MsoNormal">                                                               Purple sulfur bacteria live in the layer just above the green sulfur bacteria. They are unable to live in bottom area where the concentration of hydrogen sulfide is high. because high concentration of hydrogen sulfide are toxic and able to kill them. They are shown in purple color due the color of their photosynthetic pigments. Their method of ATP synthase is photosynthesis and use hydrogen sulfide as their electron donor in chlorophyll. Oxidation of hydrogen sulfide fills the electron deficiency in chlorophyll and converts into sulfur. Sulfur deposit in their cells.  Reaming hydrogen sulfide reaches to the surface layer.<o:p></o:p></div> <div class="MsoNormal">                                                      In the surface layer of the water column, oxygen is highly available. Therefore Aerobic respiratory microorganisms are abundant there. So sulfur oxidizing bacteria like <i>Thiobacillus thioxidans</i> live there. They are also called as Chemolithropic organism those who use oxidation of inorganic substrate to synthesis ATP. They use hydrogen sulfide as their substrate and produce ATP.  The oxidation of hydrogen sulfide gives electrons to run an electron chain so hydrogen sulfide is converted into sulfate ions.  Sulfate ions are highly soluble in the water.  Dissolved sulfate ions come to the bottom mud layer. Again   Sulfate is used as terminal electron acceptor by anaerobic respiratory microorganisms and release hydrogen sulfide.<o:p></o:p></div> <br /> <div class="MsoNormal">                                                      Therefore all the activities taken place in the water column are interrelated.  Product or byproducts of a reaction become substrate of electron donor or terminal electron acceptor of other reactions. <o:p></o:p></div> <script> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','https://www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-65880709-1', 'auto'); ga('send', 'pageview'); </script>

Winogradsky Column

Freshwater sample extracted from a pond is taken into a glass cylinder. As it is made of glass, light is able to penetrate through it...

Read more »