46 lab1－细菌的革兰氏染色.ppt

第1页：实验一细菌的革兰氏染色一教学要求了解不同的细菌

实验一细菌的革兰氏染色一教学要求了解不同的细菌染色方法的原理，掌握革兰氏染色方法的操作技术。二实验原理1、染色方法Since bacteria are almost colorless and therefore show littlecontrast with the broth in which they are suspended, theyare difficult to observe when unstained. Stainingmicroorganisms enables one to:-see greater contrast between the organism and the background,differentiate various morphological types (by shape, arrangement,gram reaction, etc.),-observe certain structures (flagella, capsules, endospores, etc.)

第2页：SimplestainsSimplest

• Simple stainsSimple stains highlight the organism so basic structuresare visible in microscope.
• Differential stainsDifferential stains react differently with different kindsof bacteria.
• Special stainsUsed to color and isolate various structures, such ascapsules, endospores, and flagella.

第3页：Simplestains

Simplestains

第4页：2、革兰氏染色

• 2、革兰氏染色
• Gram Stain-developed Christian Gram in1884
• The gram stain is the most widely used stainingprocedure in bacteriology. It is called adifferential stainsince it differentiates betweengram-positive and gram-negative bacteria.Bacteria which stainpurplewith the gramstaining procedure are termedgram-positive;those which stainpinkare said to begram-negative.
• Gram-positive and gram-negative bacteria staindifferently because of fundamental differences inthe structure of their cell walls.

第5页：StructureofaGram-Neg

Structure of a Gram-Negative Cell Wall Structure of a Gram-Positive Cell Wall

第6页：三材料与器材

• 三材料与器材
• 菌种：大肠杆菌约24 h营养琼脂斜面培养物，金黄色葡萄球菌约24 h营养琼脂斜面培养物。
• 革兰氏染色液
• 载玻片、酒精灯、显微镜。

第7页：四操作步骤制片（涂片

四操作步骤制片（涂片，干燥，固定）→初染（草酸铵结晶紫染1 min，水洗）→媒染（加碘液覆盖涂面染1min，水洗，用吸水纸吸去水分）→脱色（加95%酒精数滴，并轻轻摇动进行脱色，20 s后水洗，用吸水纸吸去水分）→复染（蕃红复染约1min，水洗）→干燥→镜检

第8页：Smearpreparation

Smear preparation

第9页：

第10页：StainingHeatfixing

StainingHeat fixing

第11页：crystalvioletstainwa

crystal violet stainwash with water

第12页：Stainwithgram'siodin

Stain withgram's iodine solutionDecolorize by adding95% alcohol

第13页：CounterstainwithSafranin

Counterstain with Safranin

第14页：五注意事项

• 五注意事项
• 注意涂片不宜过。
• 火焰固定温度要适宜。
• 注意控制好脱色程度。六思考题
• 造成革兰氏染色结果不正确（假阴性或假阳性）的主要原因有哪些？