Microbiology in Agriscience and Production Agriculture 11. 01: Explain the difference between viruses and prokaryotic organisms in order to distinguish characteristics of life.
Viruses � 1. Definition- organism composed of a DNA or RNA core surrounded by a tough protein outer coat. ◦ a. NOT CLASSIFIED AS TRUE LIVING ORGANISMS ◦ b. Cannot reproduce sexually, only through division in a HOST (viruses are parasitic). ◦ c. Reproduce quickly, mutate often, and can survive harsh environmental conditions.
Side note… � Why are viruses considered “Nonliving” ◦ Viruses, like bacteria, are microscopic and cause human diseases. �But unlike bacteria, viruses are acellular particles (meaning they aren't made up of living cells like plants and animals are), consisting instead of a central core of either DNA or RNA surrounded by a coating of protein. ◦ Viruses also lack the properties of living things: They have no energy metabolism, they do not grow, they produce no waste products, and they do not respond to stimuli. �They also don't reproduce independently but must replicate by invading living cells.
Viruses � 2. Viruses are responsible for some of the most dangerous human ailments can be destroyed by altering DNA. � 3. Vectors are the agent used to carry new DNA into a cell. ◦ Viruses or plasmids are often used as vectors
Vector Examples � a. Tobacco Mosaic Virus (TMV)- ◦ often used as a vector for genetic engineering in plants- 1 long RNA molecule. � b. Bacteriophage- � c. Misc. Common Viruses- ◦ DNA packaged tightly in a protein head- often used in genetic engineering. ◦ Human Immunodeficiency Virus (HIV), Influenza, Common Cold, Measles, Norwalk, Hepatitis, & Rabies.
Vector Examples � Tobacco Mosaic Virus (TMV)- ◦ TMV was the first virus to be discovered over a century ago. Research on TMV has also led to major Nobel prize winning discoveries on general principles of life.
Prokaryotic Organisms � 1. Definition- single celled organisms that have no membrane bound organelles and no distinct nucleus. Usually have very short life spans. ◦ a. Contain free-floating DNA. ◦ b. Can be autotrophic (produce their own energy) or heterotrophic (consume other things for energy). ◦ c. Also reproduce quickly and mutate often, but are not as tough as viruses �Bacteria are the most common examples
Prokaryotic Organisms � 2. Other Examples include anything in the Kingdom Monera: ◦ a. BACTERIA ◦ b. Cyanobacteria ◦ c. Blue- Green Algae
Bacteria � Bacteria ◦ a. Can be beneficial or harmful to humans. ◦ b. Unlike viruses, bacteria are not PARASITES, and do not need a host. ◦ c. MOLDS & FUNGI INCLUDING YEAST ARE NOT BACTERIA Escherichia coli
Microbiology in Agriscience and Production Agriculture 11. 02: Outline the role of bacteria in agriculture and the importance of microorganisms in agricultural biotechnology.
Bacteria � A. Beneficial Bacteria (PROBIOTICS) ◦ 1. Provide a benefit to human activity through normal function or manipulation through biotechnology techniques. ◦ 2. Examples: �a. Nitrobactus alkalikus- bacteria occurring naturally in soil on the roots of legumes, that change nitrogen in the air to a form useful for plants (nitrogen fixing). �b. Lactobaccillius sp. - a genus of microorganisms that have been introduced to foods (often dairy products) to aid in digestion
Use of Bacteria in Agriscience � 1. Pharming- inclusion of cholesterol consuming bacteria in milk products to lower human cholesterol. � 2. Bioremediation- use of bacteria that consume contaminants in soil and water. ◦ Ex: bacteria used to “eat” oil from tanker spills, or excess organic nutrients from animal waste � 3. Biocontrol- use of beneficial bacteria in horticulture to kill harmful bacteria in soil, water, and on plant surfaces. � 4. Very few applications in renewable energy or biofuels, but LOTS OF POTENTIAL APPLICATIONS.
Harmful Bacteria � 1. Affect agriscience products or processes in a negative manner, affecting both plants and animals. � 2. Examples: ◦ ◦ a. Eescherichia coli (E. coli), B. Clostridium boutlinum (C. boutlinum), C. Salmonella enteriditus (S. enteriditus), D. Pythium spp. � 3. Methods of destruction / treatment ◦ a. Sterilization- kills all living organisms in or on a substance. ◦ b. Pasteurization- kills most harmful microorganisms, leaving some beneficial organisms surviving.
Multiform Bacteria � 1. Can be either beneficial or harmful to plants under different circumstances and conditions. � Examples: ◦ a. Agrobacterium tumefaciens- naturally occurring bacteria that penetrates plant cells transmitting its own DNA to the cells and causing the growth of a gall (tumor like mass). �i) Used in genetic engineering to transmit genes.
Microbiology in Agriscience and Production Agriculture 11. 03: Discuss the structure and function of eukaryotic cells and the role of these cells in the formation of life.
Eukaryotic Cells � 1. Definition- advanced cells characterized by the presence of membrane bound organelles, and a distinct nucleus. ◦ a. Usually occur in multicellular animals, but also include a few single celled Protists.
Eukaryotic Cell Structures � Structures ◦ ◦ ◦ of ALL cells Cell membrane Golgi apparatus Mitochondria Nucleus Ribosomes Vacuoles
Eukaryotic Cell Structures � a. Cell membrane- ◦ selectively permeable membrane surrounding all eukaryotic cells. ◦ Protects the cell and controls the movement of substances into and out of the cell.
Eukaryotic Cell Structures � b. Golgi apparatus- ◦ center for the distribution of proteins, enzymes, and other materials through the cell. (like the post office)
Eukaryotic Cell Structures � c. Mitochondria- ◦ structures inside the cell that convert simple sugars to a useful form of cellular energy through the process of respiration.
Eukaryotic Cell Structures � d. Nucleus- ◦ a large central segment of eukaryotic cells that contains the cell’s genetic information (DNA).
Eukaryotic Cell Structures � e. Ribosomes- ◦ small structures in the cytoplasm of the cell that utilize RNA to produce proteins for cell functions.
Eukaryotic Cell Structures � f. Vacuoles- ◦ specialized “bubbles” in cells used for storage, digestion, and excretion. Much larger in plant cells.
Structures Specific to Plant Cells � a. Chloroplasts- � b. Cell wall- ◦ specialized structures in plant cells that utilize chlorophyll to capture light energy for conversion to chemical energy. ◦ structure outside the cell membrane that helps support and protect cells. Not semi-permeable.
Specialized Eukaryotic Cells � Diploid cells � Haploid cells � Stem cells
Specialized Eukaryotic Cells � 1. Diploid cells- ◦ includes all single celled eukaryotes and every nonreproductive cell in multicellular eukaryotes. (plants and animals) �a. Ex: skin cells, muscle cells, nerve cells, etc.
Specialized Eukaryotic Cells � 2. Haploid cells- specialized reproductive cells in Eukaryotes that contain ½ the amount of genetic material of normal (diploid) cells. ◦ a. Also called Gametes or sex cells. ◦ b. Haploid cells combine during sexual reproduction to create a fertilized egg. ◦ c. 4 distinct types: �i) male- sperm or pollen �ii) female- egg or ovum
Specialized Eukaryotic Cells � 3. Stem cells- ◦ produced from the union of haploid cells, special cells that differentiate into all diploid cells in the body. ◦ These cells can differentiate into any diploid cell or remain the same (undifferentiated)
Microbiology in Agriscience and Production Agriculture 11. 04: Apply laboratory skills in the culturing of microorganisms and cells.
Ideal Bacteria � 1. Most bacteria prefer warm moist environment, though different species require different culturing conditions. ◦ a. Bacteria thrive in the harshest environments on earth- ex: deep sea ocean vents with no sunlight and little useable oxygen.
Techniques for Culturing Bacteria � 1. Bacteria Testing Methods ◦ a. Swabbing- method used to test surfaces for bacteria. �i) A sterile cotton swab is dipped in a dilution solution and rubbed across the surface to be tested. �ii) The end of the swab is cut and dropped into the solution. �iii) The infested solution is swirled and. 1 ml extracted for plating. ◦ b. Simple Dilution- used to test food and liquids for the presence of bacteria. Sample should be liquefied and diluted to various concentrations before being plated.
Techniques for Culturing Bacteria
Techniques for Culturing Bacteria � 2. Plating- the process of physically spreading bacteria on an agar based culture media. ◦ a. To produce agar plates, heat a clear solution in a water bath. Next, proceed to pour the solution into Petri dishes and immediately seal. (Agar must be heated to be liquefied so that it can be poured. ) ◦ b. Bacteria can be spread using an inoculating loop or glass “hockey stick”. �i) The slow movement of a cotton swab or inoculating loop is done to introduce bacteria to a culture plate. ◦ c. Plates should be sealed and incubated at 30°C to avoid the growth of most bacteria harmful to humans. (35°C – 37°C for Salmonella, etc. )
Identifying-Counting Bacteria � 1. Different agar mixes can be used to culture specific types of bacteria. � 2. Gram staining is used to broadly identify certain types of bacteria. � 3. Identifying individual strains is much more difficult.
Cleanup after Culture Labs � 1. Cultures should be placed in a biohazard bag for sterilization in an autoclave set at 121° C and 15 psi for 15 minutes. � 2. Agar should be disposed of according to lab protocol- not poured down sinks, as liquid agar can quickly solidify and clog drains � 3. Individuals should always wear latex gloves and immediately dispose of them after use. This is due to the hands being the most common point of contact.