Effect of Growth Factors Microbiology PDF

Effect of growth factors  ‫‪Table of Contents‬‬ ‫دراسة تركيز أيون‬ ‫‪1‬‬ ‫العوامل البيئية المختلفة‬ ‫‪3‬‬ ‫الهيدروجين (درجة‬ ‫الحموضة)‬ ‫‪2‬‬ ‫دراسة درجة الحرارة‬ ‫‪4‬‬...

Effect of growth factors  ‫‪Table of Contents‬‬ ‫دراسة تركيز أيون‬ ‫‪1‬‬ ‫العوامل البيئية المختلفة‬ ‫‪3‬‬ ‫الهيدروجين (درجة‬ ‫الحموضة)‬ ‫‪2‬‬ ‫دراسة درجة الحرارة‬ ‫‪4‬‬ ‫دراسة االحتيج اكأكسجي ي‬ Physical factors Physical factors affecting microbial growth: Temperature H+ ion concentration Oxygen Requirements 1 Temp.  ‫تأثير درجة الحرارة‬ Temperature strongly influences the multiplication and metabolic processes of microbes. Characteristic values as: the speed of multiplication is at the maximum rate :Optimum Temperature the speed of multiplication is at the lowest rate. If :Minimum Temperature temp. is decreased by 1 degree, Multiplication rate stops. :Maximum Temperaturethe speed of multiplication is at the highest rate. If temp. is increased by 1 degree, Multiplication rate stops.  Thermophilic Bacteria Depending on 45- 65 oC where the occur in soils optimum value is, bacteria can be in compost piles 60−65°C differentiated into Bacillus stearothermophilus three groups Mesophilic Bacteria 20 – 45 oC Bacillus subtilis Psychrophilic Bacteria 10 – 20 oC supercooled waters of the Arctic and Antarctic. Pseudomonas fluorescense  Practise Fresh nutrient agar.2 slants Inoculate with a.3 loopful of the ‫*منظر امامي‬ bacterial culture ‫*منظر جانبي‬ Unknown.1 bacterial strain ‫م‬°5 ‫م‬°25 ‫م‬°37 ‫م‬°55 slant culture Observe the intensity of.5 Incubate at 5, 25, 37.4 bacterial growth and 55 oC  Results ‫م‬°5 ‫م‬°25 ‫م‬°37 ‫م‬°55 ‫*منظر امامي‬ + ++ +++ - Weak growth Mid. growth High growth No growth Bacillus subtilis  Effect of temp. on metabolism 1. At temperatures above the maximum, enzymes will begin to denature and lose activity. 2. Below the minimum temperature, chemical activity slows down and some denaturation can also occur. 3. In addition to the effects on enzyme activity, temperature can also greatly affect cell membranes and transport. A. As temperature decreases, transport of nutrients into the cell also decreases due to fluidity changes in the membrane. B. If the temperature increases above the maximum of an organism, membrane lipids can be destroyed, resulting in serious damage to the membrane and death of the organism. 4. Last, ribosomes can be directly affected by temperature, and if extremes of temperature occur, they will cease to function adequately. 2 pH  Effect of pH on microbial growth pH, effects transport through cell membrane and limits the activity of enzymes concentration of hydrohen ions at which the bacterial :Optimum pH growth is the most intensive. The lowest pH value that an organism can tolerate. If pH is decreased by 1 :Minimum pH degree. Growth stops. Maximum pH : The highest pH value that an organism can tolerate. If pH is increased by 1 degree. Growth stops. The hydrogen ion concentration affects proteins and other charged molecules in the cell. Each organism will have an optimal pH at which it grows best. If pH values exceed the optimum for an organism, the solubility of charged molecules in the cell can be adversely affected and these molecules can precipitate out of solution. For example, the pH can directly affect the charge on amino acids in proteins and result in denaturation and loss of enzyme activity.  Acidophiles pH 3 - 5 Thiobacillus thioxidans Based on optimum pH, Neutrophils bacteria are pH 6 – 7.2 differentiated E. coli into 3 groups ‫بكتريا محبة للقلوية‬ Alkaliphiles pH 8 -11 Bacillus alcaliphilus  Practise Glucose broth with different pH values.2 Inoculate with a.3 loopful of the ‫*منظر امامي‬ bacterial culture Unknown ‫الميكروب‬ ‫ مزرعة‬.1.1 3 5 7 9 bacterial strain ‫ ساعة‬24 ‫بعمر‬ pH ‫درجة ال‬ slant culture Observe the intensity of.5 Incubate at 30 C.4 bacterial growth for 48 h.  Results pH 3 pH 5 pH 7 pH 9 ‫*منظر امامي‬ - + +++ ++ No growth Low turbidity Intensive Mid. Turbidity turbidity Bacillus subtilis  Oxygen 3 requiremen ts  Oxygen requirements Oxygen requirements of bacteria reflect the mechanism used by them, to satisfy their energy needs. On the basis of oxygen requirements, bacteria can be divided into following different categories: Strict anaerobes Strict aerobes Lack superoxide dismutase Require oxygen, Have no fermentative Generally lack catalase pathways. Generally produce superoxide Are fermenters dismutase Can not use oxygen as terminal electron acceptor Bacillus subtilis ClostridiumFacultative sp. anaerobes Will respire aerobically until oxygen is depleted and then ferment or respire anaerobically E.coli Microaerophiles Lack superoxide dismutase Generally lack catalase Are fermenters Can not use oxygen as terminal electron acceptor Aerobes: Aerobes grow in ambient air, which contains 21% oxygen and small amount of (0.03%) of carbon dioxide. Aerobes require molecular oxygen as a terminal electron acceptor so cannot grow in its absence. Anaerobes: Usually bacteria of this group can not grow in the presence of oxygen, oxygen is toxic for them. They use other substances as terminal electron acceptor. Facultative anaerobes: They are versatile organisms, capable of growth under both aerobic and anaerobic conditions. They preferentially use oxygen as terminal electron acceptor Microaerophiles: Microaerophiles are those groups of bacteria that can grow under reduced oxygen (5% to 10%) and increased carbon dioxide (8% to 10%). Higher oxygen tensions may be inhibitory to them.  Shake ‫ المزرعة المهتزة‬-1 Culture Method Inoculate with a loopful.3 ‫*منظر امامي‬ of the bacterial culture Shake well between hands Unknown ‫الميكروب‬ ‫ مزرعة‬.1.1 Nutrient deep agar melted at 100 and.2 bacterial strain ‫ ساعة‬24 ‫عمر‬ cooled at 45 C slant culture Observe the location of.5 Incubate at 30 C.4 microbial growth for 48 h.  Microaerophiles Results Strict anaerobes Facultative anaerobes Strict aerobes Clostridium sp. Lactobacillus lactis E.coli Bacillus subtilis  Stab Culture ‫ الوخز‬-2 Incubate the deep agar by.3 stabbing it with a loopful ‫*منظر امامي‬ of the bacterial culture Unknown ‫الميكروب‬ ‫ مزرعة‬.1.1 Nutrient deep agar melted at 100 and.2 bacterial strain ‫ ساعة‬24 ‫بعمر‬ cooled at 45 C slant culture Observe the location of.5 Incubate at 30 C.4 microbial growth for 48 h.  Microaerophiles results Strict anaerobes Facultative anaerobes Strict aerobes Clostridium sp. Lactobacillus lactis E.coli Bacillus subtilis