Tuesday, July 28, 2009

The Finished Telescope Shiner Gill Fluke Picture

We now have all 8 months of telescope shiner collections from the Walls of Jericho analyzed for gill fluke infection. If I remember correctly this represents 256 individual fish. I want to thank Andrew, Joey, Sabrina and Alan for their work this summer in removing gills, staining them, and examining them microscopically for the presence of Dactylogyrus gill flukes. The most obvious feature of the graph below is a spring peak of infection followed by a sharp drop off in August and September. This is very similar to the pattern of gonadal maturation in telescope shiners, which also peaks from April to July. So the fish spawn while carrying their maximum parasite load, apparently. I still have to run the monthly parasite numbers through ANOVA to ascertain the statistical significance of apparent month to month differences in average parasite infection. The error bars are one standard error.

Friday, July 24, 2009

Pictures From Last Week's Trip To Little Cypress Creek

Here are some photos from last Tuesday's trip to Little Cypress Creek in Lauderdale County, AL, at the County Road 8 bridge. We really intended to go to Cypress Creek at CR 8, but my pre-set confusion lead us astray. We still caught and kept a bunch of scarlet shiners, two bigeye chubs and a rainbow darter, the latter of which is doing well in a lab aquarium. But we found none of the target, highland shiners...

The first picture is a view of the creek, looking down from the fairly high bridge. It's a nice, clean stream flowing over mostly gravel and sand with riffles, riffle pools, flowing pools, all the habitat you'd like to sample on a hot day. I'm sure we could have caught lots of other species here, three years ago we found a few flame chubs at this site.

Here's the back of my truck after netting, with various gear spread around. I'm convinced it's a good idea to keep the spare tire in easy reach. And the hand from the lower left is truly attached to a full body.

Andrew is happy to have a freshly euthanized scarlet shiner to show the world.

Wednesday, July 22, 2009

Parasite Infection Of Telescope Shiners Varies Seasonally

Students in my lab have been working this summer on a project that might seem like a white whale. They've been pulling the gills from the preserved telescope shiners that we collected monthly from February through September in 2007 from Hurricane Creek at the Walls of Jericho, and counting the number of gill flukes (Dactylogyrus spatulus) from each fish. We have ~30 fish from each month, so it's a reasonable data set. February through July are now finished, and it's shaping up as an interesting story. There's a rise in infestation from February (1.5 flukes per fish) to May (almost 6 flukes per fish), and then a decline in June and July. The numbers are significantly different at least between May on one hand, and February and July on the other. Check out the graph below, with error bars equal to one standard error.
We've heard anecdotally that parasite numbers in shiner-type fishes seemed to have a seasonal basis, but there's next to nothing in the literature about it. So once we finish the August and September collections we'll have the basis for a short article, demonstrating that at least telescope shiners show evidence of a seasonal variation in gill fluke numbers. I still have no good idea why this is, but it certainly needs more research.

Monday, July 20, 2009

No New DNA, No Highland Shiners, But Lots Of Coal Ash

I've been away for a long weekend to visit my father on the Virginia shore, without benefit of internet. But now I'm back to catch up.

The coal ash angle is a new article in Newsweek about the coal ash spill near Kingston, TN, last December and the threat of similar spills around the country (including two sites in Alabama). The article is at http://www.newsweek.com/id/207445. The idea of mobilized lead, cadmium, arsenic, and selenium in a flowing muddy mass is less than attractive.

The stippled studfish DNA sequencing attempt failed last week. For an unknown reason our purified DNA samples had very low DNA levels. It's puzzling since I was sure we were doing it better than several years ago, when we got a good set of sequences. So it's back to the drawing board.

And the trip to the Cypress Creek system in Lauderdale County, AL, last Tuesday went great except that we didn't catch any highland shiners, the primary target. Due to my confusion we stopped at Little Cypress Creek along County Road 8 rather than Cypress Creek on the same road, where we've caught highlands years ago. We wound up with 30 scarlet shiners, of which I initially thought some juveniles were highlands. So we'll try again on Friday, now that I'm sure I know where we're going(!). We did catch and bring back a live male darter that we can't identify. At first I thought he was a redline darter, but breast coloration and the second dorsal fin are all wrong. The general arrangement is more like a rainbow darter, but there are some important differences such as a largely red second dorsal fin with a terminal white band, no color on the pectoral fins and wrong color pattern on the caudal peduncle and caudal. I have to get a decent photo of him to circulate, hopefully not just advertising my ignorance. More than anything I think he's some kind of "orangethroat" darter but they aren't found in Alabama. We'll look for more of these on Friday.

Our mummichog DNA sequences are now up on genbank. The first of them is at http://www.ncbi.nlm.nih.gov/nuccore/253796555, going to number ...583. The 28 listings in this scheme represent a 70% complete cyt-b gene sequence for each fish, along with a separate protein sequence translation entry. Kris is making a push to finish his thesis with this data, hopefully soon!

Monday, July 13, 2009

OK, We'll Resubmit To NeuroReport

The editor of NeuroReport is open to us resubmitting our NMDA receptor paper (with no snarky comments this time, I hope). We'll include our recent western blots of scarlet, telescope and silverstripe shiner brains, all of which reinforces our original observation of variation in male and female brain size and function related to reproductive strategy. So we have to come up with a figure showing these NMDA concentration differences. We think we know what need to do on that... Andrew's on it, so away we go.

Also, as a follow-up to my previous post on my lab -- I'm happy to let people play music in the lab as they work as long as no one feels too offended. My basic house rules are simple: no Lynyrd Skynyrd, and no Dave Matthews Band. Anything else is fine: death metal, punk rock, acid damage, etc.

Friday, July 10, 2009

My Lab, 19 Months In

I took a series of 4 photographs of my lab this morning, starting at the door and ending photographing the door. When I moved in I posted a few shots of a fairly barren looking lab. Now it looks more lived in, especially this summer with more intense work going on with the gill fluke and neuroecology projects. I even try to keep the counters cleaned off, wiping off the dirt, salt, scales, etc.

Here's the view walking in the door and looking down one aisle.

Moving to the left and looking down the other aisle, from the aquariums to the window:

Going down to the end of this second aisle and looking back towards the aquariums:

And finally, moving again to the left and looking down the first aisle towards the door (the wine bottles are for Travis if he comes in for bottling his home brew wine):

No one else was around, so all of the microscopes are covered up in this series. In closing, here's a photo of one of the orangespot sunfish in my 55 gallon aquarium. He's still not full grown but he looks good, and the photo is almost good:

Wednesday, July 08, 2009

Silverstripe Shiners Are Like Telescope Shiners

This is not a big surprise, since silverstripe shiners (Notropis stilbius) are close relatives of the telescopes (N. telescopus). In particular, the results of our western blots last week with NMDA subunit 1 from 7 silverstripes' brains showed the same pattern as with telescopes: no sexual structuring of NMDA concentration, unlike with the scarlet shiners (Lythrurus fasciolaris). From high to low, the pattern with silverstripes was: M, F, M, M, F, F, M. At the suggestion of Ernie in the Bishop lab I calculated the male average vs. female average, along with standard error, and found that males have a slightly higher average amount of NMDA than females, but not statistically signficantly so. The same is true with telescope shiners. On the other hand, doing the math for scarlet shiners showed that males have a statistically significant higher concentration of NMDA than do females. As a funny thought, I didn't think to do that at first because we have low sample sizes with the western blots, from 7 to 10, and because of my background in ecology I unconsciously thought of these as very small samples (which they are, of course). But in neuroscience these are perfectly robust sample sizes, since running western blots is such a tedious process.

So now I'm convinced that we've demonstrated that there is a phylogenetic basis for NMDA in fish brains, in turn related to breeding strategy: strong sexual dimorphism with high-NMDA males (scarlet shiners), or low sexual dimorphism with no significant NMDA differences between males and females (telescope and silverstripe shiners). The bigger question is what drives this difference -- is it the influence of different levels of steroids like 11-KT, or something further upstream like AVT release by the hypothalamus? This is a much more challenging question to address, but I think we've got to head in that direction.

A silverstripe shiner, from my files (thanks to the Biology Dept. at Samford University):

Monday, July 06, 2009

The Telescope Shiner Manuscript Is Accepted

I just heard from the administrative assistant at the journal American Midland Naturalist that they've accepted our manuscript, "Reproductive Timing of the Telescope Shiner, Notropis telescopus, in Alabama, USA". Andrew and I still have to rework some of the figures but I hope we can do that this week. I'm amazed at their fast decision, I know they received the revised manuscript only last Wednesday. But I'm happy for that!

Andrew is now working on the densitometry of our western blots from last week. We should know soon if the silverstripe shiners show an NMDAR pattern more like their also mildly sexually dimorphic telescope shiner relatives, or more like their much more distant relatives the very sexually dimorphic scarlet shiners. And the winner is: ________.

Friday, July 03, 2009

A Western Blot From Today

I'm not even sure which fish are on this blot, but it's one of three that Andrew, Alan and Selina worked on over the past two days. The bands of interest are the first major row down from the top, which is subunit 1 of the NMDA receptors in the various fish brains. The first lane on the left is mostly empty because what they used as a positive control doesn't really work; lane 10 on the right is the size ladder, itself a positive control of sorts. Andrew will scan the three blots on Monday and get our densitometry numbers. The blots contain a mix of silverstripe shiners from Tuesday, telescope and scarlet shiners from Estill Fork last November, and three of our most recent telescope and scarlet individuals from the last blot for comparison. The basic hypothesis is that fish from last fall should show relatively low NMDA since it's after breeding season, and we expect silverstripe shiners to be very similar to telescopes since they're closely related. But, we'll see...