{ "experiment": { "id": 436, "name": "Transformation of E. coli with electroporation", "description": "This template will show you how to transform E.coli bacteria with electroporation. In molecular biology, transformation can be artificially induced through the creation of pores in the bacterial cell walls. \r\nElectroporation is the use of high-voltage electric shocks to introduce DNA into cells. It can be used with most cell types, yields a high frequency of both stable transformation and transient gene expression and, because it requires fewer steps, can be easier than alternate techniques.", "project_id": 223, "created_by_id": 202, "last_modified_by_id": 202, "archived": false, "archived_by_id": null, "archived_on": null, "restored_by_id": null, "restored_on": null, "created_at": "2018-11-13T09:57:55.843Z", "updated_at": "2019-02-07T14:41:26.829Z", "uuid": "59b17955-fba6-405a-a6b8-6a78a05af66f" }, "my_modules": [ { "my_module": { "id": 2166, "name": "Analysis of transformation", "due_date": null, "description": null, "x": 67, "y": 7, "my_module_group_id": 1165, "created_at": "2018-11-13T15:51:41.812Z", "updated_at": "2018-12-13T15:38:36.161Z", "archived": false, "archived_on": null, "created_by_id": 202, "last_modified_by_id": 202, "archived_by_id": null, "restored_by_id": null, "restored_on": null, "workflow_order": 3, "experiment_id": 436, "state": "uncompleted", "completed_on": null }, "outputs": [], "my_module_tags": [], "task_comments": [], "my_module_repository_rows": [], "user_my_modules": [], "protocols": [ { "protocol": { "id": 3508, "name": null, "authors": null, "description": null, "added_by_id": null, "my_module_id": 2166, "team_id": 1, "protocol_type": "unlinked", "parent_id": null, "parent_updated_at": null, "archived_by_id": null, "archived_on": null, "restored_by_id": null, "restored_on": null, "created_at": "2018-11-13T15:51:41.820Z", "updated_at": "2019-02-20T07:58:02.380Z", "published_on": null, "nr_of_linked_children": 0 }, "protocol_protocol_keywords": [], "steps": [ { "step": { "id": 5189, "name": "Obtaining single colonies", "description": "\n
\nFor each electroporation, 2.5, 25 and 250 pl of cells, each in duplicate, were spread on LB plates containing 12.5 mg/mL chloramphenicol. For transformations of ligations with the vector, plates contained 50 µg/mL X-gal and 25 µg/mL IPTG.
Growth conditions:
There are many factors that can influence transformation efficiency. Therefore after each transformation, an assessment of efficiency is needed.
For gene expression common methods used:
Culture samples are aliquoted to microfuge tubes (100-200 µL/tube) and frozen quickly in a dry ice-ethanol bath. Store at -70°C until use.
", "position": 3, "completed": false, "completed_on": null, "user_id": 202, "created_at": "2018-11-13T10:35:19.862Z", "updated_at": "2019-02-07T12:58:44.529Z", "last_modified_by_id": 202, "protocol_id": 3504 }, "checklists": [], "step_comments": [], "step_assets": [], "assets": [], "step_tables": [], "tables": [] }, { "step": { "id": 4438, "name": "Centrifugation", "description": "\nFollow the steps for centrifugation below.
", "position": 2, "completed": false, "completed_on": null, "user_id": 202, "created_at": "2018-11-13T10:55:00.370Z", "updated_at": "2018-12-24T08:25:52.273Z", "last_modified_by_id": 202, "protocol_id": 3504 }, "checklists": [ { "checklist": { "id": 954, "name": "Guidelines:", "step_id": 4438, "created_at": "2018-12-21T07:49:43.577Z", "updated_at": "2018-12-21T07:49:43.577Z", "created_by_id": null, "last_modified_by_id": null }, "checklist_items": [ { "id": 3917, "text": "Centrifuge samples for 10 min at 5000 r.p.m.", "checked": false, "checklist_id": 954, "created_at": "2018-12-21T07:49:43.580Z", "updated_at": "2018-12-21T07:49:43.580Z", "created_by_id": null, "last_modified_by_id": null, "position": 0 }, { "id": 3918, "text": "Resuspension in a volume of cold 10% sterile glycerol equal to the original culture volume.", "checked": false, "checklist_id": 954, "created_at": "2018-12-21T07:49:43.588Z", "updated_at": "2018-12-21T07:49:43.588Z", "created_by_id": null, "last_modified_by_id": null, "position": 1 }, { "id": 3919, "text": "Cells are collected by spinning for 10 min at 5000 r.p.m. at 4°C.", "checked": false, "checklist_id": 954, "created_at": "2018-12-21T07:49:43.595Z", "updated_at": "2018-12-21T07:49:43.595Z", "created_by_id": null, "last_modified_by_id": null, "position": 2 }, { "id": 3920, "text": "After decanting the supernatant, cells are resuspended in the volume of glycerol remaining in the centrifiuge bottles and spun for 10 min at 7000 r.p.m. in a centrifuge.", "checked": false, "checklist_id": 954, "created_at": "2018-12-21T07:49:43.604Z", "updated_at": "2018-12-21T07:49:43.604Z", "created_by_id": null, "last_modified_by_id": null, "position": 3 }, { "id": 3921, "text": "After decanting the supernatant, cells are resuspended in 10% glycerol, using a volume of between 2 and 2.25 m/L initial culture.", "checked": false, "checklist_id": 954, "created_at": "2018-12-21T07:49:43.611Z", "updated_at": "2018-12-21T07:49:43.611Z", "created_by_id": null, "last_modified_by_id": null, "position": 4 } ] } ], "step_comments": [], "step_assets": [], "assets": [], "step_tables": [], "tables": [] }, { "step": { "id": 4437, "name": "Incubation", "description": "\nA fresh overnight culture of Escherichia coli is diluted 1:1000 for growth in SOB medium.
Incubation until density is 108 - 2x108 .
SOB medium:
Mark the required number of microcentrifuge tubes. Place the required number of cuvettes (0.1 cm gap) on ice. Before use remove the bacteria and aliquots of DNA from the freezer, thaw briefly at room temperature, then place on ice before electroporation. A mixture of cells and DNA: 30µL of cells and 2 µL DNA is added to microfuge tubes.
Using a micropipette, pipette 20 µL of the cell-DNA mixture in cuvettes. Do not leave an air bubble in the droplet of cells; the pressure of a bubble may cause arcing and loss of the sample. Place the chamber in a slot and note its position.
Repeat the process if more than one sample is to be pulsed. Handle the cuvettes gently to avoid accidentally displacing the sample. Close the lid and secure it with the draw latch. Set the electroporation settings.
Electroporations are performed in duplicate.
Conditions:
The plasmids were resuspended in 20µL TE (10 mM tris-CI pH 8.0, 1 mM EDTA) and store in aliquots at -20°C.
DNA concentration is measured in two ways:
Plasmid DNA isolation procedure by Birnboim and Doly (1979). The method has been used principally with plasmid pBR322 and its derivatives in E.coli strains HB101, RRI and SK 15921.
All manipulations are carried out at room temperature unless otherwise indicated.