乳品微生物实验2（Dairy Microbiology Experiment 2）.docVIP

乳品微生物实验2（Dairy Microbiology Experiment 2） Experiment two simple staining and Gram staining of bacteria First, the purpose of the experiment Two 、 experimental principle Three. Experimental materials Four 、 experimental process Five 、 experimental method Six, matters needing attention Seven, experimental work First, the purpose of the experiment 1. learn the basic techniques of microbial smears and staining. 2. master the simple staining method of bacteria. 3., preliminary understanding of the morphological characteristics of bacteria, consolidate the use of oil mirror method and aseptic operation technology. Two 、 experimental principle 1. simple staining: staining a bacterium with a dye to show its morphology, unable to distinguish the structure of a bacterial cell, usually using an alkaline dye (such as methylene blue, crystal violet, magenta etc.) the coloring. 2. Gram staining: established in 1884 by C.Gram, a Danish pathologist. Gram staining allowed the differentiation of all bacteria into gram Gram positive bacteria (G+) and gram negative bacteria (G-) are the two most commonly used differential methods in bacteriology. This method of dyeing can therefore be fine The bacteria are divided into G+ bacteria and G- bacteria, which are determined by the differences in the cell wall structure and composition of the two species. Fixed purpose The bacteria must be fixed before staining. Its purpose is two: One is to kill bacteria and stick them to the glass; - two is to increase its affinity for dyes. Two common methods are heating and chemical fixing. When fixed, try to maintain the original shape of cells. Gram staining principle: The first step: crystal violet, so that bacteria purple Second step: iodine and crystalline violet form macromolecular complexes that are large enough to be blocked by cell walls. The third step: alcohol decolorization, cell wall composition and structure are different, there are different reactions. The fourth step: yellow sand Furan, ne