Invasive freshwater fish (Leuciscus leuciscus) acts as a sink for a parasite of native brown trout Salmo trutta (2020) Tierney et al. Biological Invasions. Read it here.
From house cats to cane toads, invasive species are one of the biggest threats to native plants and wildlife, second only to habitat destruction. An invasive species is a living organism that is a) introduced by humans from its native range to an area it doesn’t naturally occur, b) spreads and forms new populations and c) causes some kind of damage to the native ecosystem, economy or human health. Current lockdown conditions notwithstanding, introductions of invasive species have become increasingly common in our globalised world with easier travel and trade between countries. The spread of invasive species creates new ecological interactions between native and invasive species that can impact how our native ecosystems function, including disease dynamics. If the development and transmission of native parasites is different in invasive hosts compared to their usual native hosts, the parasite dynamics of the whole system can be altered.
The impact of parasites can often reach beyond their individual hosts, shaping populations and communities in their ecosystems. Parasites often control the behaviour of their hosts, leading to their role as “ecosystem engineers,” changing the ways in which the hosts physically shape their environments.
In lakes
and rivers, gammarid amphipods, small shrimp-like crustaceans, are known to act
as ecosystem engineers by digging into the sand, in a process called
bioturbation. Bioturbation is a major process in the ecosystem, as this digging
alters the concentration of oxygen in the sand, the concentration of nutrients
in the water, and the biological communities living in and on the sand. We
wanted to know whether the amphipods would dig into the sand more or less when
infected with behaviour-changing parasites, like Polymorphus minutus, and whether the temperature of the ecosystem
influenced the rate of digging.
Every year, the Trinity College Dublin Zoology, Botany, and Environmental Science moderatorship students (final year undergraduates) complete their own research projects related to their course. It has been my absolute privilege to spend time with these talented students and to watch their projects take shape. I am blown away by the dedication they show, the incredible topics they cover, and the way in which they approach their investigations. After their theses are submitted, the students hold a poster session where they present their work. From beetles to beer and back again, this year’s students have done impressive and solid work. I hope all our readers enjoy learning about these projects as much as I did! If you’d like to contact any of these students to congratulate them, offer them prizes/jobs, or learn more about their projects, most of them have included contact information. Without further ado, I’ll let them take it away! -Maureen Williams, PhD Student, Zoology
Last week, the Zoology department hosted the first Irish One Health workshop, welcoming speakers and attendees from a range of disciplines. This gathering provided an opportunity to discuss the One Health initiative, which aims to solve world health problems through transdisciplinary collaboration, through a series of short presentations discussing various aspects of global health, and ample time for discussion between attendees, including representatives from the DAFM, EPA, HSE and AFBI.
Our own Dr Peter Stuart, who organised this workshop, gave a fascinating introduction to the concept of One Health, using the example of Hookworm in the American South during the 20th century as proof that we need to work collaboratively to solve current health issues.
Professor William Campbell with Professors Celia Holland (front right) and Yvonne Buckley (front left). Back row L-R Professor Holland’s parasitology research group: Dr Peter Stuart, Gwen Deslyper, Maureen Williams, Rachael Byrne and Paula Tierney
“Parasites are not generally regarded as being loveable. When we refer to people as parasites we are not being complimentary, we are not praising them. We tend to think that a parasite is the sort of person who goes through a revolving door on somebody else’s push. This is unfair. It’s unfair to real parasites… It is time for parasites to get a little more respect!” – Professor William C. Campbell during his 2015 Nobel Prize acceptance speech.
In 2015, Prof. William C. Campbell, a Trinity Zoology graduate, won the Nobel Prize in Physiology or Medicine, for his discovery of ivermectin. The drug can be used to treat a wide range of parasites, but is most widely known for its effectiveness against river blindness. In 1987 the pharmaceutical company Merck enabled the free distribution of the drug to developing countries.
This Nobel Prize, which Prof. Campbell shared with his then colleague Prof. Satoshi Ōmura, is an important accomplishment not only for the Professors themselves as the cherry on top of their careers, but it is also important for the wider academic community.
This Nobel Prize is of importance to what Prof. Celia Holland described as ‘the international worm community’. This community has been struggling for many years to get recognition and funding. This prize therefore finally highlights the importance of parasitic worms. A lot of these parasites are often, despite their wide prevalence, classified as ‘neglected tropical diseases’. Neglected tropical diseases mainly affect the poor communities and are often forgotten in research and in the ‘public health agenda’. It remains to be seen whether some parasites will ever be able to shake their neglected status, but this Nobel Prize and associated international attention could be a great step in the right direction.
Hopefully, other pharmaceutical companies will take note of this prize. Giving away lifesaving medicine should be celebrated. We all know of the negative press pharmaceutical companies have gotten such as the recent price hikes in epi-pens. However, we tend to forget and ignore when pharmaceutical companies go to great lengths to help those in need. I see this prize also as a celebration of Merck for showing how it can be done differently. Because, really, what is the point of us producing any medical research if it doesn’t translate into affordable medicine?
During Prof. Campbell’s visit to TCD, the provost announced a new lectureship position in parasitology in honour of Prof. Campbell and the work he has done for the international worm community. Needless to say that this position would not have existed without Prof. Campbell’s Nobel Prize. Parasitology is a struggling field worldwide and every lectureship position is one to be valued and celebrated. This lectureship shows the commitment of the university to parasitology and will reinforce Trinity’s leading role in parasitological research within Ireland.
Additionally, this is an inspirational story for a lot of people. The story of ivermectin is a great motivation for parasitologists like myself. I work on a parasitic nematode called Ascaris, which infects 800 million people worldwide every year. Much like river blindness, it is also a neglected tropical disease, and as is often the case for these types of diseases, there isn’t much interest or funding going around. So it’s great at the start of my PhD to see that this type of research can also be honoured and valued.
I’ve read interviews of Prof. Campbell where he said that this prize meant the end of his retirement. I’m sorry to hear that his well-deserved retirement has been shaken up, but Prof. Campbell took one for the team and is promoting parasitic worm research to whoever wants to listen, just as he did before, only now he has a broader audience.
Author: Gwen Deslyper (seen charming Bill at 1:49 )
On the 15th and 16th April we had one of my favourite events at Trinity College Dublin: the annual School of Natural Sciences Postgraduate Symposium. Over the course of two days many of our PhD students presented their work to the School. We also had two amazing plenary talks from Dr Nick Isaac (CEH) and Professor Jennifer McElwain (UCD). For those of you who are interested in exactly what we work on here at EcoEvo@TCD, here are the abstracts from the PhD student presentations. Check out the TCD website for more details!
Karen Loxton [@LoxtonKaren]: Parasite lost: Helminth parasites in the invasive bank vole in Ireland.
Invasive species are a major cause of biodiversity decline throughout the world. Determining why some species become invasive when introduced to a new environment is therefore of great importance. One hypotheses is that invasives escape their native parasites and are ‘released’ from the effects of parasitism. This project looked at the intestinal helminth parasites of the invasive bank vole to determine if it is less parasitised than in its native ranges.
Kevin Healy [@healyke]: Digging how you wing it! Extrinsic mortality and longevity in volant and fossorial endotherms. *Highly commended*
Longevity is a fundamental life history trait that exhibits considerable variation among species. While longevity strongly correlates with body size many species live either far longer, or indeed shorter, than expected. Classical life history theory predicts that species that experience high extrinsic mortality will, on average, evolve shorter lifespans. We tested using phylogenetic comparative methods in birds and mammals whether species that either possess abilities or live in environments that reduce predation display longer lifespans. Our results showed that as predicted traits such as volancy, fossoriality and foraging in arboreal environments are associated with long-lived species.
Louise Esmonde: Plant selection for use in a submerged macrophyte vegetation (SAV) wetland under temperate conditions.
Constructed wetlands are seen as a sustainable and low carbon alternative to conventional wastewater treatment solutions. Submerged Aquatic Vegetation (SAV) wetlands utilize the ability of submerged macrophytes to remove nutrients and metals from the water phase to treat wastewater. This study uses the relative growth rates (RGR) of a number of submerged macrophyte species as an aid in selecting the best species for use in a SAV wetland. So far the RGR of the submerged macrophyte species Myriophyllum spicatum, Elodea canadensis and Ceratophyllum demersum have been measured. RGR was found to be in the order: E. canadensis > M. spicatum for planted specimens and M. spicatum > E. canadensis > C. demersum for unplanted specimens. Research is on-going into the treatment potential of these species in terms of nutrient and metal removal from wastewaters.
Melinda Lyons: Petrified plants – the ecology of lime-rich springs
Petrifying springs are intriguing ecological and hydrogeological features with extreme chemical conditions in which specialised plant species thrive. They deposit ‘tufa’, a porous rock, on the ground surface and on plants where lime-rich spring water emerges. Recent measurements of tufa accumulation show surprisingly rapid growth rates. This distinctive habitat (a priority habitat in Annex I of the Habitats Directive) is being investigated in Ireland for the first time. Analysis of relevé data indicates that different subtypes occur depending on topographical settings. Some examples are of particularly high conservation value, most notably those on the Benbulbin Range of Counties Sligo and Leitrim. The habitat is vulnerable to changes in water flow and quality, land use practices and visitor pressures.
Hanan Elshelmani: MicroRNA profiling in serum of Age-Related Macular Degeneration patients
Age-related macular degeneration (AMD) is a common condition causing a progressive visual impairment, leading to irreversible blindness. This condition is characterised by loss of central vision attributed to degenerative and neovascular changes that occur in the neural retina and the underlying choroid. In what we believe to be the first study of its kind, here we aimed to establish if circulating miRNAs may exist which are associated with AMD and so may have relevance as novel test for rapid screening, early diagnosis; disease sub-typing; and/or treatment selection for AMD. Results: Unsupervised hierarchical clustering (performed using dChip software) indicated that AMD specimens have a different miRNA profile compared to that of healthy controls. Overall 157, 207, 190 miRNAs were detected in control, neovascular and atrophic respectively. 56 and 11 miRNAs, respectively, were found to be detectable at significantly higher levels in serum specimens from neovascular and atrophic patients compared to control sera. Interestingly, only 5 differentially-expressed miRNAs overlapped between atrophic and neovascular patient groups; suggesting biomarker specificity for different types of this condition.
Patricia Coughlan: The phylogenetics of paclitaxel biosynthesis genes in Taxus baccata, Taxus hybrids and allies
Taxus baccata, more commonly known as the Irish Yew, is a natural producer of Paclitaxel. Bristol Myers Squibb developed an effective anti-cancer drug from Paclitaxel and gave it the trade name Taxol. Taxol is used to treat ovarian, breast and lung cancer. This project will develop molecular primers to amplify and study the genes involved in the Taxol biosynthetic pathway, and take a phylogenetic approach to discover which genes are more important for paclitaxel production. More specifically, it will discover variation in these genes between Taxus baccata and Taxus hybrids such as Taxus xmedia.
