lab1.docx

**Lab- lec 1** **LAB safety & microbiology equipment** **\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--** **Lab safety Rules :** 1. Wear appropriate PPE (Personal Protective Equipment)...

**Lab- lec 1** **LAB safety & microbiology equipment** **\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--** **Lab safety Rules :** 1. Wear appropriate PPE (Personal Protective Equipment), including safety Lab coats, gloves, and closed-toe shoes, Use equipment such as face shields, respiratory masks, or hearing protection. 2. Read and understand the labels and MSDS (Material safety data sheet)of chemicals before use.Avoid storing chemicals near heat sources or in direct sunlight. 3. No Food or Drink 4. Wash hands after handling any hazardous materials, before and after eating, and before leaving the lab.  5. During normal operations one should never work alone in a laboratory setting.  6. Treat all microorganisms as potential pathogens , Sterilize equipment and materials. 7. Never pipette by mouth. Use [pipetting devices](https://www.carolina.com/lab-supplies-and-equipment/lab-glass-plasticware/lab-pipets/10266.ct) 8. All cultures, chemicals, disinfectant, and media should be clearly and securely labeled with their names and dates. **microbiology equipment :** 1. **Analytic balance :** weighing instrument used in scientific laboratories and industries where precise measurements of mass are required.  2. **Autoclave:** is a device used to sterilize equipment and materials(commonly used for the preparation of culture media ) that effect by heat , it uses high pressure steam to kill bacteria , virus & fungi in 121c for 20 min, 3. **Biological safety cabinets ( BSC ):** to reduce the risk of infection from laboratory workers. used in microbial inoculation and isolation studies  4. **Deeb freezer :** used to store substances such as cells , enzymes or tissues that must be kept at very low temperatures 5. **Incubator :** it is a device that provides the heat necessary for the growth of microorganism.  6. **Hot air ovens :** is a labrotary instrument that used dry heat to sterilize labroratry equipment such as ( petridesh, flasks , pipettes and powders such as starch ) by desroy microorganisms & bacteria spores in 160 degrees for 60 min 7. **Water bath :** used for melting the solid media  8. **Other devices such as (** shaker, ph meter, colony counter **)** **Other tools of microbiology LAB :** 1. **Pipettes** : is a laboratory tool used to measure and transfer small volumes of liquids with high precision 2. **test tuber**  3. **slide** : used to hold and support specimens for microscopic examination. 4. **cover slide**: used to cover specimens on a microscope slide.  5. **petri dishes** : also known as Petri plates, it is commonly used in laboratories for various purposes, especially in Microbial Culturing , Colony Counting 6. **punsen burner** : is a type of gas burner commonly used in laboratories for heating and sterilizing purposes.  **Compound microscopic :** used for magnifying small objects that are not visible to the naked eye. The name **"Compound microscopic"** arise from the use of multiple lenses to achieve higher magnification. **The components of compound microscope include :** 1. (oculaire) eyepiece :this is the lens closest to the viewers eye and typically has a magnification of 10x. 2. objective lenses : compound microscope have multiple objective lenses with different magnification powers. 10x ( low power ), 40x ( high power ), and 100 ( oil immersion ) 3. Tube : connects the eyepiece to the objective lenses 4. Stage : the stage is a flat platform where the specimen is placed for observation. 5. Coarse and fine focus knobs : these knobs are used to adjust the focus of the microscope. the Coarse focus knob moves the stage up or down rapidly 6. Condenser : to concentrate and focus light onto the specimen 7. Light source 8. Arm : provide support and stability for the microscope. **Culture media :** also known as growth media or nutrient media , are substances or mixtures used to support the growth and proliferation of microorganisms, cells or tissues in a laboratory setting. They provide the necessary nutrients, P H balance and physical environment needed for the organisms to grow and reproduce. **Culture media can be classified into several categories based on their composition and PURPOSE :** 1. **Agar media** : agar is a gelatinous substances derived from seaweed , are solid or semi solid media that contain agar as a solidifying agent. these media provide a soiled surface for the growth of microorganisms and are commonly used for isolating and identifying bacterial colonies 2. **Broth media** : are liquid media that do not contain agar. they are used for growing large quantities of microorganisms in liquid suspension. 3. **Selective media** : contain specific components that inhibit the growth of certain while promoting the grow , , for EX Mac Conkey Agar , selective for G -ve bacteria and also Group D in G+ve bacteria can grows on this media 4. **Differential media:** contain specific components that allow for the differentiation of different types of microorganisms based on their biochemical properties. These media typically contain indicators or substrates that produce characteristic color changes or other visible reactions when specific metabolic activities occur, for EX Blood Agar  5. **Enriched media**: are formulated to provide additional nutrients that support the growth of fastidious microorganisms, which have complex nutritional requirements, for EX Chocolate Agar **the most important types of samples and the nutritional media for medical cultivation :**  - All media are sterilized by moist heat only ( Autoclave ) - Mac Conkey Agar Selective medium and differential between lactose fermentation bacteria and non lactose fermentation bacteria , used for the isolation of gram-negative enteric bacteria **Staining of bacteria :** Bacteria staining is a technique used in microbiology to enhance the visibility of bacteria under a microscope. It involves applying dyes or stains to bacterial cells, which helps to differentiate and classify them based on their cellular properties. **Types of bacteria staining :** - Simple staining of bacteria - The gram staining of bacteria - The staining of acid fast bacteria - Staining of bacteria spores - **Simple staining of bacteria :** is a technique used to visualize bacterial cells and their morphological features, It involves a single dye or stain to the bacterial cells, which imparts color to the cells, making them more visible under a microscope. Here\'s a general procedure for simple staining of bacteria:  - **the dye might be:** methylene blue or crystal violet - **oil added on slide :** when light passes from glass to air, some of it is reflected , resulting in a loss of light , By using a special type of oil the light can pass through the glass slide and into the specimen without being reflected back. - **The gram staining of bacteria :** is a common technique used in microbiology to differentiate bacteria into two broad categories: Gram-positive and Gram-negative**,** The method is named after Hans Christian Gram  - **The staining of acid fast bacteria (ziehl -- neelsen stain )** : is a specialized staining technique used to identify bacteria belonging to the genus Mycobacterium, including the species that cause tuberculosis (Mycobacterium tuberculosis). Acid-fast staining is based on the unique cell wall composition of these bacteria, which contains a high concentration of lipids that make them resistant to conventional staining methods**.**  - **Staining of bacteria spores :** is a technique used to distinguish between the vegetative cells and endospores , as a spore forms inside of the vegetative cell, the spore wall chemically changes and thicken. This sporulation process changes the spores stainability, making it increasingly resistant to the staining dyes,