Courses : Forest Ecology Lecturer :Frischa Adellia Semester : 4thSemester, 2022/2023 Session Definition of Resuspens Resuspension is the process of returning or hydrating a dry material or solution into a liquid or suspension form. This process is often required in various laboratory contexts, especially in molecular biology and chemistry. In the context of molecular biology, resuspension is often related to substances such as DNA, RNA, proteins, or other chemical compounds that may have been isolated or stored in dry form. Once isolated or stored in dry conditions, these substances need to be reconstituted or resuspended before being used in various analyzes or experiments. The general steps in resuspension are as follows: 1. Preparation: The dry material or concentrate solution is prepared for resuspension. This can be DNA or RNA isolated in pellet form in a centrifuge tube or a concentrated solution of a particular chemical compound. 2. Solvent addition: A suitable solvent is added to the dry material or concentrate to return it to a liquid or suspension form. The solvent used must be selected based on the chemical properties of the material to be resuspended. 3. Mixing: After addition of the solvent, the sample is gently shaken or incubated to ensure even resuspension of the dry material or concentrate into the solvent. 4. Consistency check: After mixing, the consistency and homogeneity of the solution is checked to ensure that the ingredients have been properly resuspended. This often involves visual observation or optical measurements. Resuspension is often an important step in sample preparation prior to further analysis, such as DNA analysis by PCR or sequencing, or in the preparation of working solutions from concentrated chemical compounds. By performing resuspension correctly, ensuring that the material has completely dissolved, researchers can ensure the success and accuracy of the experiment or analysis to be performed. As an example, consider the resuspension of plasmid DNA that has been isolated from bacteria after an extraction process. After extraction, the plasmid DNA often remains in dry or pelleted form at the bottom of the centrifuge tube. To use this plasmid DNA in a PCR reaction or cell transfection, it needs to be resuspended. The following are the steps for resuspending plasmid DNA: 1. Plasmid DNA preparation: After the plasmid DNA extraction process, the DNA is in pellet form at the bottom of the centrifuge tube. 2. Solvent addition: An appropriate amount of solvent (such as sterile water or buffer solution) is added to the tube containing the plasmid DNA pellet. 3. Mixing: The tube with the plasmid DNA and solvent is shaken gently to ensure that the plasmid DNA is well dissolved in the solvent. This process can involve manual stirring or incubation in a shaker or incubator. 4. Consistency check: After mixing, the consistency of the DNA solution is checked to ensure that the DNA is completely dissolved and evenly distributed in the solvent. This can be done by visual observation or optical measurement using a spectrophotometer. By properly resuspending plasmid DNA, ensuring that it is completely dissolved in the solvent, researchers can ensure the success of subsequent experiments or analyzes involving that DNA, such as cell transduction or further purification before use in a PCR reaction. In conclusion, resuspension is an important process in sample preparation in the laboratory, especially in the context of molecular biology and chemistry. Some key points that can be concluded about resuspension are: 1. Important for sample preparation: Resuspension is needed to return dry materials or concentrated solutions to a liquid or suspension form that can be used in various analyzes or experiments. 2. Important steps before analysis: Resuspension is often an important step before further analysis, such as PCR analysis, DNA sequencing, or other chemical analysis. This ensures that the ingredients are completely dissolved and ready to use. 3. Ensuring the success of the experiment: By carrying out resuspension correctly, ensuring that the material has completely dissolved in the solvent and is evenly distributed, researchers can ensure the success and accuracy of the experiment or analysis to be carried out. 4. Wide range of applications: Resuspensions are used in a variety of laboratory contexts, including in molecular biology, biotechnology, medical diagnostics, forensics, and chemistry. This includes resuspension of DNA, RNA, proteins, chemical compounds, and other materials. Thus, understanding the resuspension process is very important for researchers and practitioners in various fields of life sciences and chemistry. Properly performing resuspension ensures that samples are ready for use in a variety of analyzes and experiments, contributing to the success and accuracy of research results and laboratory applications.