Once again, I find myself interested in a paper about the analysis of a fossil! This time the point of interest is origin of the tetrapod limb digits. The origins of the proximal elements of the tetrapod limb are well understood, and can be seen as homologues of elements of the fins of sarcopterygian (lobe-finned fish). The origins of the digits may have been fin rays, or possibly evolutionary novelties. The latter explanation was supported by developmental genetic studies and analysis of fossils (including the subject of this paper, the transitional fish/tetrapod Panderichthys). In this paper, CT scanning was used to generate 3D images of Panderichthys limbs, demonstrating the presence of distal radials, and correcting a mistaken reconstruction.
The figure below shows the skeletal structure of the limb, coloured to show homologies to the elements of the tetrapod limb. 

I've been re-reading this book, which I bought and first read when it was published 21 years ago.  It is rather unfortunately out of print now, but is available online.  L. Ron Hubbard was a pulp fiction writer who, after a less than distinguished wartime career in the US Navy, reinvented himself though Dianetics, later used as the basis for the pretty bizarre Scientology cult. [Note: Scientologists react to criticism fairly aggressively.  Critical websites may be attacked by litigation or other means.  For example, note the warnings at the Wikipedia page, and this article at The Register and entries about Scientology at Wikileaks]

New Humanist magazine (they of the humanist trading card fame) - have an advent calendar in which every day in the run up to the annual midwinter festival of conspicuous consumption one of:

a stellar selection of comedians and scientists speaks about explains which scientist or philosopher they would like to celebrate each year as a rational substitute for Jesus, as well as what scientific Winterval gift they'd most like to receive.

Today I received this email from a moderator on the BT Broadband forums:

Your recent posts titled: "Re: Internet Radio Bandwidth usage?" and "Re: How do I delete my account?" have been removed as they contravene with the Forum Guidelines.

I have installed the AntiPhorm plugin.  This conducts two checks - firstly to identify if you are using BT-Webwise (by checking cookies), and secondly to check if you are using BT or one of the other ISPs who have publicly stated they are planning to implement the Phorm system.  If either of these two conditions are met, you will see a warning banner beneath the web page header.  You can carry on browsing the site.

If you see the warning banner, please take the time to visit the link for more information about Phorm, and its intrusive (and probably illegal) deep packet inspection by which your internet habits will be monitored in order to sendyou targeted advertising. The Phorm system is branded BT-Webwise when implemented via British Telecom.  Some points:

• BT-Webwise intercepts your internet communications - likely to be illegal under RIPA
• The system is "opt-out" rather than "opt-in", so you will be enrolledif you don't respond to the invitation to join.  This disregards legal requirements
• Even when opted out, your internet browsing will be passed through Phorm's profiling equipment
• Email read through web applications is likely to be profiled
• The system disregards website copyright

Here's a further update on the BT Total Censorship and the general BT-Webwise situation - for more background, see part 1,  part 2, part 3 and follow this thread at the nodpi.org forum. 

For much of my professional career as a Drosophila geneticist I've worked with polytene chromosomes, and it's always interesting to see papers with interesting tidbits of information about their structure and function. Polytene chromosomes are those rather strange structures formed from high levels of chromosome endoreduplication (see this blog article for a detailed description). Polytene chromosomes are widespread in flies, and in Drosophila are mostly studied in the larval salivary glands where they are easy to work with: Calvin Bridges used salivary gland polytene chromosomes to construct his polytene chromosome map. In this paper, Tom Hartl and colleagues show Condensin complexes (which have a function in chromosome condensation and anaphase chromosome segregation; and in vitro can induce and trap DNA supercoiling) can cause polytene chromosome disassembly and antagonise transvection.  Their data link processes of chromosome condensation and DNA supecoiling with higher order interphase nuclear structure that impacts on gene expression.

Unlike salivary gland polytene chromosomes, those of ovarian nurse cells break down during the development of the nurse cells, at about mid-oogenesis.  In this paper, two mutant alleles of a predicted component of the condensin II complex, Cap-H2 are studied.  In flies mutant for Cap-H2, the nurse cell polytene chromosomes don't disassemble.

This recent paper caught my eye, as as some of my recent research has related to the regulation of antimicrobial defence in Drosophila.  Insects have a two ways of coping with microbial infection.  Firstly, microbes may be dealt with by circulating blood cells (haemocytes) of which there are several classes.  Haemocytes to no play any role in respiration in insects.  A second means of controlling microbes involves several peptides that kill bacteria or fungi:  these are usually expressed in response to the presence of microbes in the haemolymph.  Interestingly, this induced system has a counterpart in vertebrates.  It's generally thought that the important system in clearing pathogenic microbes in insects is the induced antimicrobial peptides.  This paper investigates the roles of both systems.

The authors have evaluated the relative use of these two mechanisms of infection control in Tenebrio molitorI, the mealworm (picture above).  Their hypothesis is that the haemocytes represent the first line of defence, with the induced response of antimicrobial peptides mopping up microbes remaining from the first round defence.  In this model, the induced antimicrobial response largely functions to eliminate suviving pathogens that may be refractory to the first line of defence.

Here's a brief update on the BT Total Censorship and the general BT-Webwise situation - for more background, see part 1 and part 2, and follow this thread at the nodpi.org forum. 

PC World - UK Prosecutors Investigate BT Over Online Ad System PC World magazine pick up on stories that the Crown Prosecution Service is now investigating illegal interception conducted by BT in 2006 and 2007.

Section 41 blog - Two Conferences Raise Concerns over Phorm  Reports from two recent conferences on internet privacy, in which BT's activity came in for comment.

There's an interesting news article in Science, entitled Last Stand for the Body Snatcher of the Himalayas?, concerning a fungus with quite unusual habits.  The full citation can be found at the end of this article.

Cordyceps sinensis is a pretty strange fungus - it infects ghost moth caterpillars, and in doing so alters their behaviour such that when they hibernate for the winter, they orient themselves on end and near to the surface.  Over the winter, the fungus consumes the caterpillar and eventually pushes a fruiting body above ground.  In the picture below, you can see remnants of the caterpillar, from which the brown 'mushroom' protrudes (picture from wikipedia).