Tuesday, September 30, 2008

The Telescope Shiner Article Is Submitted

I just mailed a manuscript and digital copy on CD of our article "Reproductive Timing of the Telescope Shiner, Notropis telescopus, in Alabama, USA" to a journal, The American Midland Naturalist. Hopefully they'll like it and agree to publish it.

Here's the Abstract of the article:
Gonadal condition of the cyprinid stream fish Notropis telescopus (telescope shiner) was monitored over the course of a likely breeding season to determine reproductive schedule. The study site was at the southern limit of species range in northeastern Alabama. Notropis species are multiple spawners with strong seasonality to gonadal size and condition. The number of maturing oocytes observed in ovaries peaked in April and May. Ripe and fully mature ovaries were found in fish collected in April, May and June. A pronounced peak in the gonadosomatic index (GSI) was found in June for both males and females. Females were found to be significantly larger than males. The evidence points to an Alabama spawning season from April to June, peaking at the end of this season.

Monday, September 29, 2008

Telescope Shiner Brain

Above is a dorsal view of the brain of a male telescope shiner we collected in June, 2007, at Hurricane Creek at the Walls of Jericho. This brain is 6.3 mm long. The telencephalon, or forebrain, is at the top of photo. The optic tectums are the two large lobes on the side behind that, the cerebellum is tucked in behind the optic tectums, and the dorsal medulla (an extension of the spinal cord) runs out of that into the shadow at the bottom of the photo. We have top, bottom and side photos of each brain so that we can calculate total brain volume, and the volumes of the telecephalon, optic tectums and cerebellum. We have 20 fish from June photographed, and on Wednesday Brittany, James and Alexandria will weigh these brains. And then they're on to do May, and maybe April, fish from the peak spawning time of telescope shiners. Do males have bigger brains than females, as is true of scarlet shiners? I hope to know soon.

Saturday, September 27, 2008

Scarlets & Brains

Jennifer has decided that she'd like to do a talk at the SFC meeting rather than a poster, so that's fine with me. Her thesis defense was well done so I'm sure it can be boiled down to a 15 minute talk.

We're back in gear on the telescope shiners brain project. Brittany has removed the brains of 10 males and 10 females from our June collection at Hurricane Creek. This week we'll begin to photograph them so we can make digital measurements of specific areas for volume calculations, before weighing them and going on to May fish for the same treatment. To extend the project, we're going to Hurricane Creek (below the Walls of Jericho tract) next Saturday to look for young of the year telescopes for brain measurements. It's no guarantee that we'll find them, of course, but if we even just find some adults that will be good for the purposes of running Western blots of their brains to assay for NMDA receptors. Brittany, James and Alexandria all blanched at the thought of dissecting out the brain of a 20 mm fish. As always, we'll see...

Sunday, September 21, 2008

We'll Do A Scarlet Shiner Poster At SFC In Chattanooga

I heard from Jennifer the other day. She and her co-workers on the slackwater darter project were invited by Jim Williams to present a poster on their work at the upcoming SFC (Southeastern Fisheries Council) meeting in Chattanooga in November. They will, and Jennifer also wants to present a poster on her work on scarlet shiner 11-KT levels. I told her great, let's do it! It'll be a good exercise for putting together a journal article on the work in the near future. I feel better already about this work.

Tuesday, September 16, 2008

Telescope Shiner Article Nearly Ready

I have a tight draft of the telescope shiner article near ready, nine pages of intro and text with one table and three figures. It's short but to the point. All of the evidence we collected shows that telescopes are reproductively competent from April - June, which is what has been generally observed before. But I'm sure of it now... Andrew and Brittany have copies of all of this for review, as co-authors. From here I'll have to track down Lindsay and Loren as the other two co-authors. I know that Loren is at the Sea Lab so that shouldn't be too hard. If this looks good to everyone, I have it pretty much formatted for submission to American Midland Naturalist.

Meanwhile, we're still trying to figure out how to get clean sequences from the stippled studfish DNA. We're achingly close; is it a question of using the right H primer, or keeping the reaction tubes cold during the GeneClean gel purifications? I hope to tell you soon.

Friday, September 12, 2008

We Have Telescope Shiner Brains, And Almost Have Stippled Studfish DNA Sequences

Brittany has been soldiering away dissecting out brains from fixed telescope shiners from last year. She's getting good results, and the brains look pretty similar to scarlet shiners (not surprisingly). We'll know if we're on to anything when we take digital microscope images and measure the volume of the overall brain, and specific areas such as the vision-processing optic tectum. I'd guess we'll find differences, but if I knew it wouldn't be research.

We've been sending out PCR products of fish DNA to be sequenced at Operon. Our first studfish sample is messy but salvageable. Kris' mummichog DNA samples are more problematic, 2 kinda worked and 2 didn't. We have to arrange for Operon to use new primers and re-run the reactions to see if they'll work better.

I gave a talk to an honors science class on Wednesday about the studfish project. It went well, no one fell asleep and they asked intelligent questions. It was a good time for me to organize what we've found to date and figure out what it means.

Tuesday, September 09, 2008

DNA Sequences Soon, Brain Dissection Practice

Kris has dropped off his last four mummichog DNA sequences at Operon to be sequenced, apparently we'll receive them in the next day or so. And he dropped off one of our stippled studfish sequences, a fish from Hillabee Creek, as a test sequence which should be ready tonight. Hopefully we're about to receive lots of sequence information. It seems almost routine nowadays, so bring it on.

And I showed Brittany how to dissect intact brains out of scarlet shiners this afternoon. She's game for the telescope shiner project, so we're practicing on some scarlets we collected last April. On her first solo fish she almost got the whole brain out intact, only slashing some of the telencephalon. Another one or two and she'll be ready for one of the June telescope shiners. It's yet another form of real biology!

Thursday, September 04, 2008

A New Shiner Brain Project

Jennifer (and Alexandra?) has agreed to start work on a project to characterize brain size in telescope shiners, Notropis telescopus. We have lots of telescopes left over from last year's project, each in a tube of buffered formaldehyde sexed and measured. The interesting thing about this is that we can compare them to scarlet shiners. Scarlets are sexually dimorphic, with larger, colorful males. Telescopes are not sexually dimorphic, and I have trouble telling adult males from females. We've found pronounced differences in scarlet shiner brains between males and females. So, the question is, are similar differences present in telescopes? The two species are found in the same creeks, such as Hurricane Creek at the Walls of Jericho, so both should be well adapted to living in clear, flowing waters. But they probably have different reproductive ecologies (I realize I'm not sure exactly how telescopes spawn; I'd bet it doesn't involve alpha males defending territories, unlike scarlets.)

We're going to use the telescope shiners from May and June, what we found to be the peak of the spawning season, to compare them to scarlet shiners that we examined from the peak of their spawning season. With no pronounced sexual dimorphism, are male brains not very much larger than females, or maybe even females have bigger brains? I have no idea, which of course makes for fun research.