Martin and Scholtz, 2012

Martin P, Scholtz G. 2012. A case of intersexuality in the parthenogenetic Marmorkrebs (Decapoda: Astacida: Cambaridae). Journal of Crustacean Biology 32(3): 345-350. http://dx.doi.org/10.1163/193724012X629031

Abstract

We describe an intersex specimen of the Marmorkrebs, the only obligate parthenogenetic freshwater crayfish with an all-female population. The individual was a fully functional female which possessed male-like first pleopods. Nevertheless, it reproduced successfully and the offspring were normally developed parthenogenetic females, lacking any trace of male traits. The general rarity of aberrant sexual traits in freshwater crayfishes, in particular in Procambarus, is discussed. We suggest that a dysfunction of the sex determining system, which controls the anlagen of the androgenic glands during development, caused the partial male-like phenotype of this Marmorkrebs specimen. The application of this organism for investigations of sex determination and differentiation is recommended.

Keywords: aberrant secondary sexual characteristics • androgenic gland • gonochorism • gynandromorphy • hermaphroditism

Soedarini and colleagues, 2012

Soedarini B, Klaver L, Roessink I, Widianarko B, van Straalen NM, van Gestel CAM. 2012. Copper kinetics and internal distribution in the marbled crayfish (Procambarus sp.). Chemosphere 87(4): 333–338. http://dx.doi.org/10.1016/j.chemosphere.2011.12.017

Abstract

Metal pollution e.g. copper, in water bodies occurs worldwide. Although copper is an essential trace metal, at certain levels it is still considered as pollutant. The aim of this study was to investigate the effect of exposure concentration on copper bioaccumulation in marbled crayfish (Procambarus sp.) by determining uptake and elimination kinetics. Crayfish were exposed to sub-lethal copper concentrations (average measured concentrations of 0.031 and 0.38 mg Cu L⁻¹) for 14 d and transferred to copper-free water for another 14 d. At different time points during the uptake and elimination phases copper concentrations were measured in five organs (exoskeleton, gills, muscle, ovaries and hepatopancreas). At 0.031 mg Cu L⁻¹, copper levels in the crayfish organs were not significantly increased compared to the control animals, suggesting effective regulation. Exposure to 0.38 mg Cu L⁻¹ did lead to not significantly increased copper levels in muscles and ovaries, while the gills and exoskeleton, which are in direct contact with the water, showed significantly higher copper concentrations. In these four organs, copper showed fast uptake kinetics with equilibrium reached within 10 d of exposure. Copper accumulation was highest in the hepatopancreas; uptake in this storage organ steadily increased with time and did not reach equilibrium within the 14-d exposure period. Copper accumulation levels in the marbled crayfish found in this study were hepatopancreas > gills > exoskeleton > muscle.

Keywords: copper • toxicokinetics • bioaccumulation • hepatopancreas • marbled crayfish

Crawling out of the swamp May 1st!

Get your donations ready!

SciFund 2: Return of the Marmorkrebs!

You may recall that last year, I had a Marmorkrebs project in the inaugural SciFund Challenge.

I’m pleased to report that Marmorkrebs and I will both be back in the next SciFund challenge, starting in May.

But not together.

Kyle MacLea will be carrying the banner for Marmorkrebs in Round 2. To learn more, you should follow Kyle’s blog, By Way of Science. He’s also on Twitter and Google Plus.

This is an opportune time to update people on the status of the project I successfully launched in round 1. I contacted some experts on Procambarus fallax in Florida, and the answer I got was consistent. The best time to collect for that species was... November. News will be slow on the first #SciFund project, then.

As for my own project in SciFund 2, you can read about it over at my other blog, NeuroDojo.

TCSERA 2011

Last year, I live-blogged the announcement that Gerhard Scholz had been award The Crustacean Society’s Excellence in Research Award. He was not at the meeting to accept his award, but the latest issue of Journal of Crustacean Biology discusses his research contributions in more detail and allows him to reply. I am pleased to see it does not leave out Marmorkrebs.

In 2003, Gerhard reported the first parthenogenetic decapod, a cambarid crayfish (Marmorkrebs) found in the aquarium trade. It was subsequently shown that these animals originated in Florida, and molecular evidence revealed that they were in fact a form of Procambarus fallax that has established itself in several European countries as well as Madagascar, thus uncovering a harmless pet primed to become a devastating invasive species.

In his comments, Dr. Scholz offers this bon mot:

Life without crustaceans is possible, yet pointless!

Reference

McLay C, Boyko CB, Schram FR. 2012. Gerhard Scholtz Recipient of the Crustacean Society Excellence in Research Award. Journal of Crustacean Biology 32(2):341-344.

Might we finally get a crayfish genome?

I just learned of a new project, Arthropods Genomes, which aims to sequence 5,000 arthropod genomes. The project wiki is here, which includes a form to suggest species to include for sequencing.

No need to rush. I suggested Marmorkrebs for sequencing before I started writing this post.

This should be no surprise, given that a crayfish genome is something I’ve been asking for for years. Indeed, every time someone mentions how bored they are with yet another genome being sequenced, or how hard it is for the poor genome researchers who are drowning in so much data, it’s become a running joke for me to say, “Yeah, yeah... So where’s my frickin’ crayfish genome‽”

As of this writing, four decapod species are in the draft list. The Lousisiana red swamp crayfish, Procambarus clarkii, is on the draft list of species. This is a good choice, as we know more about its biology than probably any other crayfish.

I hope this pans out.

Related posts

Olivia’s fantasy genomes
Genome research: Good idea, bad idea
The first crustacean genome

Hat tip to Ed Yong and Alex Wild.

Crayfish chemistry? Publishing error, or just added value?

Around March 19, I got an alert for a new Marmorkrebs article appearing in PubMed. It is a very interesting article about a Marmorkrebs with some male characteristics.

I was surprised by the journal, which was not one I recognized. “Biomaterials science”? Well, I suppose crayfish could be inspiration for biomaterials. I went to the link out...

Polymer edition? I was even more puzzled. There didn’t seem to be anything in the abstract about biomaterials, and especially not polymers.

One of the authors of the paper, Gerhard Scholz, confirmed that the article wasn’t supposed to be in Journal of Biomaterials Science, but Journal of Crustacean Biology. I kept watching all week for what would happen to the article.

By Friday, the article was appearing in the “Fast track” section on IngentaConnect for Journal of Crustacean Biology. The DOI for the article didn’t change.

The PubMed entry, however, still points to the polymer journal. How or when that will be updated, I don’t know, but I’ll keep checking.

This raises the question of how publishers should correct mistakes. Retraction Watch blog has a section devoted to retractions cause by “publisher error.”  Here, there has been no retraction, or notice, or explanation to the readers of Journal of Biomaterials Science - Polymer Edition. True, the error was short-lived, and the critical identifier – the DOI – was stable.

The case of the PubMed ID will be interesting to watch, because Journal of Crustacean Biology is not normally indexed in PubMed. As far as I can discover, there is only one other article (“Effect of microgravity and hypergravity on embryo axis alignment during postencystment embryogenesis in Artemia franciscana (Anostraca),” PMID: 11539283) from the journal’s history in PubMed. Whether the article will stay in PubMed, have the corrected citation information, and have the PubMed ID will stay the same, remains to be seen.