today’s phenomenon
TRANSCRIPT
Today’s Phenomenon:
UC Davis https://www.ucdavis.edu/news/zika-virus-and-other-ailments-take-flight-infographic
San Gabriel Valley Mosquito & Vector Control District: http://www.sgvmosquito.org/newsevents_articles_details.php?aid=68
https://www.youtube.com/watch?v=2wA9YJNxRSA
Video
Article
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3775348/pdf/nihms504082.pdf
DNA Extraction Insect Identification
Overview of the Wolbachia laboratory component
709 bp
438 bp
Gel Electrophoresis PCR
Insect Orders
Approx 30; many taxonomists disagree on the # of orders and their names
“ptera” means wing.
Wings are the most obvious
way that the orders differ
http://www.backyardnature.net/insects.htm
“Key to Insect Orders” app
Online version: http://www.discoverlife.org/mp/20q?guide=Insect_orders
tarsomeres
3 pairs of legs
compound eye
pretarsus
Main insect characteristics Chitinous exoskeleton
3-part body 3 pairs of jointed legs
2 antennae Mouthparts
Compound eyes
Insect Identification
https://www.youtube.com/watch?v=1ErcwogWbIA
After Lunch – Revisit the Phenomenon
Possibly the most common intracellular bacteria in the biosphere
Found in ~66% of arthropod species; 20% of all insects contain it
Transmitted through eggs needs host to produce females
Can alter host biology to promote their survival
.
What is Wolbachia?
Nature Reviews Microbiology 6, 741-751 (October 2008)
Maternally inherited microbial infections that manipulate the reproduction of their host species towards the production or survival of
infected female hosts
Wolbachia is a Reproductive Parasite
Employs 4 strategies to increase # of infected females
Widespread Lateral Gene Transfer from Intracellular Bacteria to Multicellular Eukaryotes Science. 2007 Sep 21;317(5845):1753-6
Host chromosomal rearrangements new protein products Acquisition of new genes (gain-of-function) Disruption of existing genes (loss-of-function) Reproductive isolation and speciation Rapid change, Reduced genetic diversity Accumulation of mutations between isolated groups
Horizontal Gene Transfer
Approximately one-third of sequenced invertebrate genomes contain Wolbachia genes
HGT is more frequent between unrelated species than scientists previously believed
This poses dramatic implications for evolution
Wolbachia can insert its genome into the host cell
https://www.youtube.com/watch?v=F3G3oPUfh60
Wolbachia Infection Reduces Blood Feeding Success in Dengue Fever Mosquito
http://wolbachiamap.herokuapp.com
Duplex PCR Results
Students can expect a positive Wolbachia diagnosis in one out of five insects.
1. 100bp Ladder
2. Fly from SJSU lab, ‘11
3. Ladybug from Mt. View, ‘09
4. Aphids from my tomato plant, ‘10
5. Ant from Sunnyvale, ‘09
6. Large mosquito from San Mateo, ‘09
7. Wol+ control, Nasonia, ‘10
1 2 3 4 5 6 7
709 bp
438 bp
Gene #1: Cytochrome C Oxidase (CCOI) This is a gene that is present in all insects. It is used to verify that you had a successful DNA extraction. This gene will be present in all samples, regardless of whether or not the insect is infected with Wolbachia. It serves as an internal cntrol, or a reference gene, to make sure that your reaction worked. The PCR product for this goene will be 709bp in length. Gene #2: Wolbachia specific ribosomal DNA (Wspec) This gene is only found in Wolbachia, and will be present only if your insect was infected. The PCR product for this gene will be 438bp in length.