Jumat, 30 Januari 2009


Happy Friday! Here's a real treat. Two Virtual labs you can play around with this weekend! :)

But before you do we need to update your internet browser...click the link below so you can download and install the Adobe Shockwave 11 plugin: http://get.adobe.com/shockwave/thankyou/

Ok, now that you are all powered up with Shockwave, get ready for some virtual lab time!

Virtual Lab 1: Transgenic Fly Lab

This lab will familiarize you with the science and techniques used to make transgenic flies. Transgenic organisms, which contain DNA that is inserted experimentally, are used to study many biological processes. In this lab, you will create a transgenic fly to study circadian rhythms. (Click here for more on experimental design.) The fly glows only when a certain gene involved in circadian rhythms is activated. After making the glowing fly, you will use it to explore basic principles of circadian biology and genetics.

Teachers: Click here for more information on how this exercise can be used in your classes.

Basic Steps

1. Make transgenic flies.
o Prepare DNA that will be incorporated into the fly genome.
o Prepare fly embryos.
o Inject fly embryos with DNA.
o Breed flies.
o Select transgenic progeny.
o Examine light output from transgenic adults.

The period gene is a key component of the fly's molecular clock (Bargiello, et al., 1984; Darlington et al. 1998; Wager-Smith, and Kay, 2000; Young 2000). The period (or per) gene's transcription and translation oscillate in a regular pattern that has a period of 24 hours. A mutation in this gene results in a fly with an altered period; the name period was therefore given to this gene (Konopka and Benzer 1971). (Click here for more on the discovery of the period gene.) This predictable pattern is harnessed in the experiments here to provide a window into how clock molecules change. Specifically, part of the period gene is linked to the luciferase gene (per-luc) such that whenever the period gene is "on," light is produced in the cells where period gene transcription is occurring (Brandes et al. 1996). This elegant model allows us to look at changes in genes simply by looking at the glow of these transgenic flies.

2. Use transgenic flies to study circadian rhythms and genetics.
o Measure per-luc gene expression (that is, light emissions) under different light-dark conditions.
o Examine diff

Virtual BIO Lab 2: Virtual Bacterial Identification Introduction
Welcome to the Virtual Bacterial Identification Lab. The purpose of the lab is to familiarize you with the science and techniques used to identify different types of bacteria based on their DNA sequence. Not long ago, DNA sequencing was a time-consuming, tedious process. With readily available commercial equipment and kits, it is now routine. The techniques used in this lab are applicable in a wide variety of settings, including scientific research and forensic labs.

Basic Steps
* Prepare a sample from a patient and isolate whole bacterial DNA.
* Make many copies of the desired piece of DNA.
* Sequence the DNA.
* Analyze the sequence and identify the bacteria.

The piece of DNA used for identifying bacteria is the region that codes for a small subunit of the ribosomal RNA (16S rRNA). We will refer to this piece as 16S rDNA. Different bacterial species have unique 16S rDNA sequences. The identification relies on matching the sequence from your sample against a database of all known 16S rDNA sequences. (Learn more about ribosomal RNA.)

Learning Objectives
* What kind of patient samples are used for the purpose of identifying possible pathogens?
* What does PCR do, how does it work, and why is it useful?
* How do you separate the desired DNA from all others?
* How does an automatic DNA sequencer work?
* Why is it possible to use a DNA sequence to identify bacteria?

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