Jumped on to the Eurostar to Paris on the 7th October and visited the https://research.pasteur.fr/en/ on the 8th October to give a seminar (‘Decoding toxin-parasite interactions in Trypanosomatids‘). Thanks to Philippe Bastin and Gerald Späth for hosting (and for treating me to some a fine French dining the evening before!), and to all their colleagues for making me welcome on the 8th.
The 20th and 24th November saw me talk about microbes to two year 6 classes at Kingsgate Primary School in West Hampstead. They were a fantastically enthusiastic group with loads of great questions, so much so that two 30 minute presentations ended up taking almost an hour and a half each! We discussed the good things that microbes do for us, some of the unpleasant things they do (always popular!) and how we fight back.
As ever, it was a nice change from the serious business of MSc student education!
20th October was spent at University College London (just up the road!) presenting data from our various T. brucei RNAi library screens – something a bit diferent for all the virologists who work in the Division of Infection & Immunity at UCL! Dr Richard Milne and Prof Greg Towers hosted, and made sure I got to meet a lot of the PIs in the Division – it was nice to hear about some of the great virology research that’s going on there.
On 25th and 26th June, Matt Rogers and I hosted a group of seven year 12 students from Dulwich College at LSHTM for an intense two days of lab work, talks and tours – ‘from molecules to cells to insects’. The idea was to give them a taste of what scientific research is like and to show them the application of some of the techniques they’ve been studying at A-level.
The boys and their two teachers arrived at 10:00 on the first day, and after being equipped with lab coats and given the essential health & safety talk, they got straight down to learning a little bit about parasites; in particular, the kinetoplastid parasites (Trypanosoma brucei, T. cruzi and Leishmania) and the devastating diseases they cause – African sleeping sickness, Chagas disease, and the various forms of leishmaniasis.
They had an opportunity to run their own experiments, using some of the techniques that are helping us to understand how the current drugs work and how drug resistance can evolve. These included DNA analysis using PCR and agarose gel electrophoresis, and protein localisation by immunofluorescence. The latter culminated on day two with a visit to the imaging suite to use the epifluorescence microscope to see the sub-cellular localisation of two trypanosome proteins involved in drug uptake.
The rest of day two was spent working on a different scale, looking at the insects that spread many medically important parasites. After Matt described the role of the sandflies in transmitting leishmaniasis, the boys had a go at the fiddly task of dissecting a sandly, an insect that is considerably less than 1 cm long! This is an essential skill that, along with a battery of molecular approaches, has enabled Matt and his colleagues to develop our understanding of the sandfly-Leishmania relationship.
Inevitably, given the lab work that we’d planned, there were lots of gaps in the schedule to allow for all the necessary incubations. On day one, these were filled by tours of the DNA sequencing and high-throughput drug screening facilities, and a talk on malaria vaccines. Day two included an impromptu demonstration of the confocal microscope in the imaging suite, a talk on the use of animals in research, and a tour of the insectories. Day two finished with a talk (and demonstration!) explaining why mosquitoes find some of us so attractive, and another looking at cutting edge approaches to controlling mosquito-borne diseases. A big thank you to all our colleagues who volunteered (with surprisingly little arm twisting!) to share their expertise and enthusiasm with the boys. Thanks to Ozan Gundogdu, Ross Pavely, Kevin Tetteh, Annie Tremp, Patricia Aiyenuro, Hollie Burrell-Saward, Nina Stanczyk and Tom Walker for all their contributions! Thanks also to Cheryl Whitehorn, Victoria Miari and Emma Cobb for letting us use your teaching labs!
Considering this was the first time that Matt and I had run a programme like this, it was remarkably sucessful, which was underlined by the feedback that we received from the boys…
‘the experience opened my eyes to the breadth and depth of research going on, which was underlined by the variety of lectures and practicals we had‘ – Jamie
‘The lecture on [the] use of animals in parasite research gave me a deeper insight on the laws and regulation of animal research in the UK‘ – Jack
‘seeing things such as the new DNA sequencing machines along with talks on the newest malarial vaccines gave us an insight into the cutting edge of the field‘ – George
With a few tweaks here and there (and hopefully with the continuing support of at least a few of our esteemed colleagues?!), we might just repeat it next year!
I joined STEMnet back in March, becoming a STEM ambassador, which all sounds rather grand, but basically involves engaging school children and their teachers in the application of science. I did a talk to a group of year 7s back in November 2013, enjoyed the experience and thought I should make it a more regular thing.
In June I got the chance to up the ante – talking to four year 9 classes at Heartlands High School, Wood Green, about what I do: molecular parasitology. It was also an opportunity to show them that studying science at any level is useful, not only for their future careers, but also can give them a greater appreciation of the world around them.
What did I learn? Year 9 are a lot more challenging than year 7! But, just as enthusiastic when they get going. And, they love the gross stuff – after all, if we’re honest, it’s probably what drew our attention to parasites in the first place! Most importantly, while the numbers can tell a story, a few graphic images can drive home the devastating impact many parasitic diseases have on sufferers and why the work we do is so important.
28th May was spent at the University of York presenting data from our various T. brucei RNAi library screens. It was nice to get out of London and to meet up with Pegine Walrad, hear about her developing lab, and meet some of the other people doing great work on Leishmania at the Centre for Immunology & Infection.
Most African trypanosomes, including the veterinary species Trypanosoma brucei brucei and T. congolense (causative agents of the wasting disease nagana in cattle), are susceptible to lysis by two trypanolytic factors in human serum – TLF1, a component of high density lipoprotein, and TLF2, an IgM/apolipoprotein-A1 complex; both complexes contain apolipoprotein-L1, which forms pores in the parasite’s lysosomal membrane (Vanhollebeke & Pays, 2010).
In contrast, the human-infective sub-species, T. b. rhodesiense and T. b. gambiense, are able to evade lysis by human serum through a variety of mechanisms. Both express truncated variant surface glycoproteins: SRA and TgsGP, respectively (Xong et al, 1998; Uzureau et al, 2013; Capewell et al, 2013). However, whereas SRA prevents APOL1 accessing the lysosome (Stephens et al, 2011), TgsGP expression only serves to hinder the membrane-APOL1 interaction (Uzureau et al, 2013). Instead, human serum resistance in T. b. gambiense also requires reduced lytic factor uptake through the expression of a mutated version of the parasite’s haptoglobin-haemoglobin receptor (Kieft et al, 2010; DeJesus et al, 2013).
Clearly, human serum serum resistance in African trypanosomes has evolved independently on more than one occasion, requiring both gain and loss-of-function mutations. But, are there other proteins that define the sensitivity of some African trypanosomes to lysis by human serum? Are there other routes to human serum resistance? Using this information, can we identify strategies to render resistant parasites sensitive to attack by human serum TLFs? In work funded by the Medical Research Council and the Wellcome Trust, we set out to define the parasite proteins that make T. b. brucei sensitive to the trypanolytic factors in human serum. Using our bloodstream-form RNAi library, we hoped to identify the full set of TLF eficacy determinants expressed by T. b. brucei.
Given the massive size (>0.5 MDa) and complexity of the lytic factors in human serum, we identified surprisingly few loss-of-function mutants that are able to confer significant human serum resistance onto T. b. brucei. As expected, TbHpHbR was the dominant hit in the RNAi library following selection in human serum. In addition, we identified the lysosomal membrane protein, p67, which is known to be important for proper lysosomal function and has previously been shown to influence sensitivity to human serum (Peck et al, 2008). Finally, we identified two proteins not previously known to influence sensitivity to human serum, ‘inhibitor of cysteine peptidase’ (or ICP) and a putative trans-membrane protein (Tb927.8.5240). ICP was subsequently, shown to be important in this pocess by Etienne Pays’ group (Uzureau et al, 2013); however, their analysis did not identify the regulated peptidase presumably responsible for lytic factor destruction.
We focussed our efforts on characterising the role of ICP in determining the human serum sensitivity of T. b. brucei. The parasite expresses two cathepsins, which constitute likely targets for regulation by ICP. Perturbations of CATB and/or CATL by chemical or genetic means had no effect on the sensitivity of wild-type cells to human serum, suggesting that ICP is able to modulate its cathepsin-suppressive effect in response to enzyme activity levels. Loss of ICP resulted in reduced sensitivity to human serum, presumably due to increased cathepsin activity against the lytic factor. Repeating the chemical and genetic perturbations of CATB and CATL in the absence of ICP, revealed that only CATL loss has a dramatic effect on the parasite’s susceptibility to lysis by human serum. Thus, we were able to conclude that ICP’s suppression of CATL activity in T. b. brucei contributes to the sensitivity of these parasites to human serum, sugesting that CATL targets the lytic factor for destruction in the lysosome.
CATL expression is essential for growth of bloodstream-form T. b. brucei, and is now recognised as an excellent target for anti-HAT drug development (Steverding et al, 2012). The above data suggests that its inhibition may render human infective sub-species susceptible to human serum lytic factors. Therefore, drugs that target this enzyme may synergise with trypanolytic factors, rendering otherwise resistant trypanosomes, sensitive to human serum. However, it should be noted that CATL may influence the production and processing of SRA and TgsGP in the endocytic networks of T. b. rhodesiense and T. b. gambiense. So, while targeting CATL may synergise with human serum, we may yet see antagonism resulting in human infective sub-species that are more resistant to human serum. Clearly, further work needs to be done to characterise the complex interactions between these factors in T. b. gambiense and T. b. rhodesiense.
Just got back from a couple of days in Wurzburg, Germany. Nicolai Siegel invited me to talk on the Microbiology Colloquium (at the Institute for Molecular Infection Biology) – on 29th April I presented our latest data on the characterisation of trypanosome factors responsible for drug and human serum efficacy.
The Institute has a great strength in bacteriology, so it was mostly an audience of bacteriologists with only a smattering kinetoplastid researchers; I may have catered more to the latter, but the questions suggested that a few of the former also found it interesting! (Some judicious editing will be required before I present this again at the end of May at the University of York!)
Apart from the talk, it was a great opportunity to catch up with Nicolai Siegel, who invited me, and Chris Janzen and Susanne Kramer at the Biozentrum, and to hear about the great work they and their teams are doing.
Some people get very exercised by accession numbers – the unique identifiers associated with genes and proteins.
When publishing results in a paper it’s accepted, and indeed rightly mandated by scientific publishers, that all associated accession numbers should be declared, so enabling follow-up analyses by other groups.
Should the same apply to conference presentations? In this case, results are often incomplete, representing work in progress, which may not enter the published record for months or even years. In contrast, peer review and publication gives a scientific paper public recognition, and also endorses its quality and contribution to the field. Papers also tend to represent complete or near complete pieces of work. Not being peer-reviewed, and rarely being complete, conference presentations have nothing like the cachet of a scientific paper.
In spite of this, many groups declare the accession numbers of the proteins they’re working on, even in conference presentations. However, others don’t. Instead, giving their proteins catchy names, so protecting their identities, while still sharing the results that make them worthy of study.
Some people find this irritating, believing that such behaviour contradicts the collegiate and collaborative foundation of science.
They believe that if you want to present your work you should present all the details, including the full identity of the protein(s) that are its subject. The assumption being that if you’re willing to present your data in a public forum, you must be so far ahead of your competitors that it won’t be worth their while jumping on the band wagon that you’ve just wheeled out! And anyway, if they did, it would be so obvious to the rest of the community that their reputation would be hammered; though what the real world consequences of this would be are anyone’s guess.
Maybe, whether or not you’re a ‘declarer’ depends on the nature of the work, the competitiveness of your field, or the characters within it – or at least your preception of any or all of these elements. After all, some results have the potential to have a huge impact on a field, but many more are incremental; though all are worthy, the former have the potential to cement reputations and make careers. Some fields are fiercely competitive. Others are populated by individuals of whom, rightly or wrongly, the moral majority are wary. Or, maybe we’d simply rather not put temptation in others’ way, and have to spend the next months (or years) worrying about what might or might not happen.
In my view, an idealistic one-size-fits-all rule can’t apply, and, ultimately, the decision to declare (or not) should be down to the individual. As long as the data are honestly presented, I’ll happily look forward to reading the published paper, if and when it comes out. When it comes to my own research, I’ll continue to deal with this issue on a case-by-case basis, depending on just how close I think I am to a complete story of any significance.
Probably, the idealists shouldn’t rush to judge, and the rest of us should be a little less paranoid. But, perhaps, as scientists we’re all just a little conflicted – wanting to work for the wider community, and often doing so, but at the same time knowing that we have to look after ourselves. After all, it’s inherent to a system where funding is short-term and hard to get, and for the most part insecurity is the only guarantee, that we sometimes feel the need to guard our most important discoveries, in the hope that we’ll be able to keep doing the science we love for the long term.
6-9th April was spent at the University of Cambridge attending the British Society for Parasitology annual meeting, including the Tryp-Leish symposium. Thanks to Mark Field (and colleagues) for organising a great meeting – his final act in Cambridge before packing up his lab and moving to the University of Dundee!
There were many great talks, but highlights included the latest findings from Federico Rojas (Keith Matthews, University of Edinburgh) on bloodstream-form T. brucei differentiation (SIF receptor, anybody?), and Lucy Glover’s talk on VEX1, a significant player in the regulation of antigenic variation in T. brucei (David Horn, University of Dundee). Mike Barrett’s CA Wright medal talk (drug resistance and modes of action) and the plenary talks by Keith Gull (trypanosome cell biology) and David Roos (apicomplexan cell biology) were also fascinating.
Finally, the meeting provided a great opportunity to talk science and catch up with friends over a beer or two in a great setting.