Showing posts with label ICOPA. Show all posts
Showing posts with label ICOPA. Show all posts

Sunday, August 24, 2014

This Month in Blastocystis Research (AUG 2014)

Some August highlights in Blastocystis research:

1) The PRE-IOPCA Molecular Parasitology Workshop took place from the 7-10 August at CINVESTAV, Mexico City. Top-motivated students from some 10-15 countries worked hard from 7 am to 7 pm in dry+wet lab sessions, and we all had a really great time, thanks to both participants and fantastic organisers. There was a 4 h session on Blastocystis molecular epidemiology, and I was pleased to learn that some of the participants currently work with (or plan to work with) Blastocystis. I look forward to doing something similar in Ankara, Turkey on the 27th of May next year ( - did you bookmark it?).

Most of the task force of the Molecular Parasitology Workshop (ICOPA 2014).
2) At the actual ICOPA conference, I chaired a session on Blastocystis in the context of IBS, with talks delivered by Ken Boorom, Pablo Maravilla, Pauline Scanlan and myself. In the audience I was honoured to see and meet Dr Hisao Yoshikawa, who has been a main contributor to Blastocystis research over the past 25 years or so (you can look up the publications by Dr Yoshikawa here). Considering the focus of this post, I guess that Pauline's talk was of particular interest, since she presented the data that we just published in FEMS Microbiology and Ecology:

3) The microbial eukaryote Blastocystis is a prevalent and diverse member of the healthy human gut microbiota. That's the title of the paper appearing in FEMS Microbiology and Ecology. The study, led by Pauline, showed that Blastocystis was present in 56% of 105 healthy adults, which is much higher than previously reported from an industrialised county (Ireland). Moreover, a diversity of different subtypes (species) were detected and Blastocystis was present in a subset of individuals sampled over a period of time between six and ten years, indicating that it is capable of long-term host colonisation. These observations show that Blastocystis is a common and diverse member of the healthy gut microbiota, thereby extending our knowledge of the microbial ecology of the healthy human intestine. And one of the interesting things here is: Why do we see this great divide? Why does half of the population appear colonised while the other half not? What are the factors driving successful Blastocystis colonisation? Would some people be refractory to colonisation or does it really boil down to some sort of enterotype-driven phenomenon as previously indicated?

4) I would like to reiterate the paper by Klimes et al. published a study in Genome Biology and Evolution (GBE) on a striking finding in the Blastocystis nuclear genome. Stop codons created by mRNA polyadenylation have been seen so far in mitochondrial genomes only and not in nuclear genomes; however, the authors observered this feature in Blastocystis's nuclear genome. Partly due to limitations of currently available annotation software, this finding ostensibly calls for reannotation of the genome currently available in GenBank (ST7). The paper was highlighted in a separate article in GBE that can be accessed from here.

5) Speaking of Blastocystis genomes: The genome of Blastocystis ST4 (WR1 strain) is now available on-line and can be accessed here.

6) Wang and colleagues studied the location and pathogenic potential of Blastocystis in the porcine intestine. They studied a total of 28 pigs from a commercial piggery, a small animal farm, and a research facility, and all pigs were positive (for ST5, and mixed subtypes were also seen in some). Post-mortem analyses showed that all pigs were consistently found to harbour Blastocystis in the colon, and approximately 90% of the caeca and rectums examined were positive. Some of the pigs were immunosuppresed (Dexamethasone), and interestingly, Blastocystis was occasionally detected in the small intestine, notably in immunosuppressed pigs, suggesting that immunosuprression may alter host-agent relations and predispose to small intestinal colonisation. Histopathological analysis saw the presence of vacuolar and granular forms of Blastocystis, but there was no evidence of attachment or invasion of the intestinal epithelium. The lack of pathology, including inflammation, epithelial damage, mucosal sloughing, and lamina propria oedema, confirmed the trend from a previous study carried out by Ron Fayer's group (see reference below). The study adds to the string of papers finding no evidence in support for Blastocystis causing primary intestinal damage.

6) Lastly, I want to extend a cordial thank you to Shashiraja Padukone and Subhash Chandra Parija, Department of Microbiology, Jipmer, Puducherry, India, for writing up a review of my 'Thoughts on Blastocystis' available on Amazon for the price of only one US$ or so. The review was published recently in Tropical Parasitology and can be accessed here.

And, for those who are worried about researchers 'overselling' microbiome research, there is a small comment in Nature calling for sound scepticism to be applied to research dealing with the relationship between the microbiome and different types of diseases. There is much to be agreed upon, and what I find particularly important, is to take the reductionist approach where possible - in terms of Blastocystis there are lots of ways to study the impact of Blastocystis on bacteria in vitro, and also host microbiota, physiology and immunology in vivo; ways that can be controlled quite diligently. Also, I think that simple validation of methods applied to map e.g. intestinal microbiota is key. This is for some reason something that is generally being utterly and completely ignored. Why?


Fayer R, Elsasser T, Gould R, Solano G, Urban J Jr, & Santin M (2014). Blastocystis tropism in the pig intestine. Parasitology Research, 113 (4), 1465-72 PMID: 24535732

Hanage, W. (2014). Microbiology: Microbiome science needs a healthy dose of scepticism Nature, 512 (7514), 247-248 DOI: 10.1038/512247a

Klimeš V, Gentekaki E, Roger AJ, & Eliáš M (2014). A large number of nuclear genes in the human parasite blastocystis require mRNA polyadenylation to create functional termination codons. Genome Biology and Evolution, 6 (8), 1956-61 PMID: 25015079

Scanlan PD, Stensvold CR, Rajilić-Stojanović M, Heilig HG, De Vos WM, O'Toole PW, & Cotter PD (2014). The microbial eukaryote Blastocystis is a prevalent and diverse member of the healthy human gut microbiota. FEMS Microbiology Ecology PMID: 25077936 

Venton, D. (2014). Highlight: Not Like a Textbook--Nuclear Genes in Blastocystis Use mRNA Polyadenylation for Stop Codons Genome Biology and Evolution, 6 (8), 1962-1963 DOI: 10.1093/gbe/evu167

Wang W, Bielefeldt-Ohmann H, Traub RJ, Cuttell L, & Owen H (2014). Location and pathogenic potential of Blastocystis in the porcine intestine. PloS One, 9 (8) PMID: 25093578 

Friday, August 1, 2014

Blastocystis in ICOPA2014

The PRE-ICOPA Workshop on Molecular Parasitology that will take place at CINVESTAV, Mexico City, is only one week away! You can download the program here. There will be sessions on local databases, genomes resources, qPCR, High Resolution Melting Curve Analysis, transcriptomics, proteomics and more, using Toxoplasma, Giardia, Leishmania, Trypanosoma and Blastocystis as model organisms.

I will be heading the 4 h session on molecular epidemiology of Blastocystis, including a 2 h dry lab session allowing students to explore the database at and get familiar with sequence assembly and basic phylogenetic analysis of complete ribosomal genes.

ICOPA 2014 will take place in Mexico City, once known as Tenochtitlán (Work by Wolfgang Sauber; source)

Blastocystis is also on the agenda in one of the ICOPA symposia: On the 11th of August, there will be a late afternoon session on Blastocystis in the context of irritable bowel syndrome (IBS). Speakers will include Dr Pauline Scanlan (IRE), Dr Pablo Maravilla (MEX), Mr Ken Boorom (US), and myself. Incidentally, Dr Scanlan + colleagues just published a paper on Blastocystis in healthy individuals in FEMS Microbiology and Ecology, - you can access the paper - or at least the abstract - here.

See you in Mexico?

Sunday, June 1, 2014

This Month in Blastocystis Research (MAY 2014)

To me, this month was mostly about Blastocystis finding its way to the ASM 2014 general meeting. It was a huge honour for me to be one of the speakers in the Parasitology session 'Passion for Parasites', thanks to an invitation from Dr Lynne Garcia and ASM.

ASM2014 took place in Boston Convention and Exhibition Center.
It's pleasing that the Blastocystis research community is continuously expanding. I currently have contact to several research groups who are venturing into Blastocystis research, including epidemiology, genome sequence analysis, and Blastocystis (and other intestinal microbial eukaryotes (IMEs)) as part of the human intestinal microbiome. At the ICOPA2014 conference in Mexico in August, there will be a full session on Blastocystis from an IBS perspective with talks by Dr Pablo Maravilla, Kenneth Boorom, Dr Pauline D Scanlan and myself. There will also be a pre-congress workshop on molecular parasitology which will include Blastocystis subtyping arranged by Dr Juan David Ramirez Gonzalez and myself.

This month we also launched the website for the 1st International Blastocystis Symposium, which can be accessed at  - we hope that the meeting will receive great interest and contribute to promoting research on Blastocystis and other IMEs. Please go to the site to sign up for updates.

Moving on to 'paper of the month', I would just briefly highlight a study by Wu, Mirza and Tan, who used Caco-2 human colonic cells and different strains of Blastocystis sp. ST4 and ST7 to compare and demonstrate the strains' relative ability to adhere to enterocytes and to disturb cell barrier function. The paper is very interesting for a variety of reasons. For instance it appears that metronidazole resistance may be linked to a fitness cost as indicated by reduced adhesion ability.

But it would be nice to know how the results reflect the in vivo situation: What actually happens in the colon? It may be so that Blastocystis can adhere to enterocytes and even inflict damage as indicated in the paper, but what if Blastocystis is not able to make it anywhere near the enterocytes?

Now, some parasites are intracellular - e.g. Cryptosporidium and microsporidia -, Giardia has a ventral disc by which it can latch on to the intestinal lining; Entamoebas are motile, etc. Blastocystis is neither intracellular, nor is it motile, but can it attach to enterocytes or is it simply being 'kneeded' and passed along with the remaining luminal content by peristalsis? Or is it lodged in the mucus layer perhaps - trapped by chance, or actively making its way to/through it?

In the colon, two mucus layers exist; an inner layer void of bacteria, and an outer layer that serves as a home for some bacteria but that also prevents these bacteria from reaching the inner layer. Hence, the colon inner mucus layer separates the intestinal lining from the trillions of bacteria inhabiting our large intestine and as such has a tremendously important role in limiting bacterial contact with the epithelium and moving bacteria distally. Mucus is produced by our goblet cells and is made up by mucins, highly glycosylated proteins that we cannot degrade. Moreover, these mucins serve as food for commensal bacteria and are highly resistant to protease activity unless destabilised. The mucus layer traps antimicrobial peptides and other immune effectors and hence creates an effective barrier between the mucosal lining and the microbiota.

Some pathogenic bacteria, and also Giardia for instance, have flagella that allow them to move against the flow caused by secreted mucins, towards the intestinal epithelium, - one way of getting past the iron doors of the mucus layer.

Entamoeba histolytica possesses a lectin-like adhesin that enables it to anchor to the inner mucus layer. After actively destabilising the mucus layer, E. histolytica can disrupt the mucus layer by cysteine protease activity and get into contact with enterocytes. By enzyme activity the parasite can cleave MUC2, the major intestinal mucin, and this may be an initial step in a series of events resulting in invasive disease; however, in many cases enzymatic cleavage of MUC2 may be blocked by glycosylation of the cleavage site; this may be one of the explanations why E. histolytica infection may only sometimes proceed to invasive disease.

Recently, Fayer and colleagues observed that in histology sections Blastocystis was seen to adhere to the intestinal epithelium. However, since about 98% of the mucus is water, the mucus layer may vanish completely during histological procedures with important consequences for the interpretation of observations.

I believe that the use of the mucosal simulator of the human intestinal microbial ecosystem (M-SHIME) would be nearly ideal for studying Blastocystis. M-SHIME is an in vitro dynamic gut model that takes advantage of five double-jacketed vessels, respectively simulating the stomach, small intestine and the three colon regions. The model is supplemented with human gut microbiota and mucin-covered microcosms. My colleagues and I have applied for funding in order to use this model to study Blastocystis ecology, but so far, we have not had any luck with the funding agencies.

Genome and transcriptome studies of Blastocystis should also enable us to identify whether this organism has and expresses proteins that facilitate invasion of the mucus layer and adherence to enterocytes and in which way these potential mechanisms may be influenced.

Note to iOS users: You have the option of making a 'Blastocystis Parasite Blog' app! When you're browsing the site on your iPad for instance, simply add the site to your home screen (use the arrow/box icon in the top of the browser), and there you go - you've created an app icon on your desktop!


Hansson GC (2012). Role of mucus layers in gut infection and inflammation. Current Opinion in Microbiology, 15 (1), 57-62 PMID: 22177113

Fayer R, Elsasser T, Gould R, Solano G, Urban J Jr, & Santin M (2014). Blastocystis tropism in the pig intestine. Parasitology Research, 113 (4), 1465-72 PMID: 24535732 

Johansson ME, Sjövall H, & Hansson GC (2013). The gastrointestinal mucus system in health and disease. Nature Reviews  Gastroenterology & Hepatology, 10 (6), 352-61 PMID: 23478383 

Van den Abbeele, P., Roos, S., Eeckhaut, V., MacKenzie, D., Derde, M., Verstraete, W., Marzorati, M., Possemiers, S., Vanhoecke, B., Van Immerseel, F., & Van de Wiele, T. (2012). Incorporating a mucosal environment in a dynamic gut model results in a more representative colonization by lactobacilli Microbial Biotechnology, 5 (1), 106-115 DOI: 10.1111/j.1751-7915.2011.00308.x

Wu Z, Mirza H, & Tan KS (2014). Intra-subtype variation in enteroadhesion accounts for differences in epithelial barrier disruption and is associated with metronidazole resistance in Blastocystis subtype-7. PLoS Neglected Tropical Diseases, 8 (5) PMID: 24851944

Saturday, February 22, 2014

'Save the Date's + Resources

Some 'Save the Date's:

1. ASM Meeting, Boston, MAY 2014:
Speaker: Christen Rune Stensvold 
Session Title: Passion for Parasites! Current Topics in Medical Parasitology 
Session Date/Time:  5/18/2014 8:00:00 AM 
Presentation Title: Blastocystis Clinical Relevance: More Common and Important than You Think

2. ICOPA, Mexico City, AUGUST 2014:
3. 1st International Blastocystis Symposium, Ankara, 28-29 MAY 2015:

Please go here for more information.

Just found out that out of 1065 Blastocystis papers in PubMed, 269 are can be downloaded for free! If you enter 'Blastocystis' in the search box, you'll see the 1065 or so hits, but if you go to the right side bar, you have the option of having the Free Full Text (269) display.

I have disabled Google+ comments for now due to repetitive abuse. However, it is still possible to comment on blog posts, only now comments will be reviewed and potentially moderated by me prior to publishing.

In case there should be readers who think that I'm trying to propagate the view that Blastocystis is pathogenic, I hope that after going through my blog posts they will realise that I'm not; in fact, I'm much more trying to be the devil's advocate: Blastocystis is 'innocent' unless proven otherwise. In my opinion we have very little clinical evidence of pathogenicity. And at our lab, we generally do not recommend treating patients with Blastocystis. In fact, we really don't know HOW to treat Blastocystis, - and maybe that's one of the most fundamental issues in Blastocystis research. I know that many treatment regimens are currently in use for Blastocystis despite the absence of clinical guidelines, and some of them are used systematically at various clinics it seems, but off the top of my head I cannot think of one single randomised controlled treatment study that have explored the microbiological and clinical effect of treatment. Such studies are critical to our understanding of  the role of the parasite in health and disease, although even this type of studies have limitations such as non-specific drug actions that will blur our ability to point out Blastocystis as the culprit, and also some drugs may have adverse effects that mimic symptoms potentially caused by Blastocystis, including symptoms related to intestinal dysbiosis. I hope that those who have extensive experience with Blastocystis treatment will soon take to sharing their knowledge.

But I guess that what we are currently trying in various fields is to get a differentiated view of Blastocystis - for instance: can colonisation turn into infection, and is there any such thing as a Blastocystis infection at all? Can, and if so, when does Blastocystis carriage lead to pathology/disease? Which are the interactions between Blastocystis and the remaining microbiota? What host factors may be responsible for potential differences in Blastocystis-mediated disease susceptibility?

Don't miss the February issue of 'This Month In Blastocystis Research' which will be available in a week or so.

Tuesday, October 8, 2013

Blastocystis Parasite Blog Hits Pageview #100,000!

I want to thank all the readers of this blog who all contribute to an increasing traffic across the site. I reckon I have between 200-400 pageviews daily, and the blog has now reached more than 100,000 pageviews! While I know that quite a few pageviews are fake (i.e. due to bots), it's still great to see visitors from all over the world stopping by, - something that makes my Blasto musings so much more worthwhile.

So, how to celebrate? Well, I've got some pretty cool announcements:

For instance, I can tell you that there is a brand new review out by Dr Pauline D. Scanlan (University of Cork) and myself in Trends in Parasitology (November issue) with some suggestions for shifts in paradigms, and it should be free for download throughout all of November! I hope that you'll enjoy it.

There's also a review out by Wawrzyniak and colleagues (members of the French group who published the first Blastocystis genome) in Therapeutic Advances in Infectious Disease available free for download here.

Congress-wise, I'm happy to announce that I've been invited to the ASM conference in Boston in May 2014 (there goes my Copenhagen Marathon dream for next year!) to give a talk at the special Parasitology Symposium with the title 'Blastocystis - clinical relevance: more common and important than you think'. Moreover, the ICOPA conference in August 2014 in Mexico City will host a symposium and a workshop on 'Blastocystis Barcoding'; more on this and the speakers included in the symposium later. Maybe I'll see you there?