A practical guide to Biomedicine career planning

By Dr Sara Namvar and Aimee Pinnington

Whilst at university it is vital that you start planning your career as early as possible. The Biomedicine academic team have prepared some guidance for you! ‘How to start planning your career’ will support you in assessing where you are up to at this moment and also provide some immediate steps you can take. ‘Building a strong CV whilst at university’ is ideally suited to first and second year students who have lost of time to get career savvy!

How to start planning your career

Building a strong CV whilst at university

Your priority must always be to achieve the best possible grades. However, extracurricular activities help you build a vast range of additional skills that not only build your CV and make you more attractive to employers, but they also make you more confident and allow you to have fun! It can be difficult to select appropriate activities both (on and off campus) to suit your career of choice.

The table below is by no means exhaustive, but maps out recommended activities to support your career of choice. In addition to these, the library, SU and careers & enterprise team offer a huge range of development opportunities. You may wish to become a student rep, ambassador at open days or mentor, which will help with all careers. Ultimately there is no right or wrong and the important thing is to get involved! You must start drafting your CV from the first year and continue developing it throughout your time at university.

Biomedicine Teaching Careers

By Dr Gemma Lace

Teaching careers are rewarding and varied. They require additional qualifications such as a PGCE but will allow you to work in primary schools, secondary schools and colleges in the UK or even abroad. They allow you to share your passion for and knowledge in a subject with children and young people, and thus be a part of inspiring the next generation of scientists, healthcare workers,  health professionals and teachers.

At our best, we are all teachers.

Maya Angelou

Where it starts after graduating: You will commence postgraduate teacher training, for instance by doing a taught PGCE or enrolling onto teach first.

Where you can end up: You could work as a teacher in primary, high school or even a college. You may end up becoming a subject head, head teacher or principal. You may even join the local council and shape OFSTED or local educational policies.

Benefits of a career in the field: Working closely with students and families is very rewarding. This career offers geographical stability and there is a clear route for career advancement (e.g. to Head of Department, Headteacher). Many teachers also spend time teaching abroad!

The Biomedicine Teaching Support Group has been established to support all those interested in teaching careers. Whether you want to be a primary or secondary school teacher and need application support, or whether you have realised teaching and mentoring skills are key to most areas of graduate employment, this support network can help you develop your CV and enhance your professional skillset.  The network officially launched on the 17th of March with the ‘Teaching Careers Symposium’ which featured external speakers, CV enhancement talks and an engaging panel discussion to help network members get ahead of the game, learn about Salford public engagement and outreach opportunities and receive top advice from experienced teachers.  Join the Biomedicine Teaching Support Group for more information.

Graduate-entry Medicine, Dentistry and Physician Associate careers

By Dr Sara Namvar and Prof. Niroshini Nirmalan

Postgraduate students may access careers in Medicine or Dentistry either at undergraduate (more expensive) or graduate-entry (more competitive) level. Only postgraduate students may access Physician Associate studies.

Where it starts after graduating: Most students will start a 2-year Physician Associate Masters. Others may apply and secure a place on a 4- or 5-year Medicine or Dentistry course. Carefully considering finances and workload both during your undergraduate degree and beyond graduation is required.

Where you can end up: A Physician Associate, Doctor or Dentist. Your career can grow in any specialty you wish. You may also get involved with university teaching/research eventually.

Benefits of a career in this field: Working closely with patients and shaping healthcare. Being able to diagnose and treat your own patients.

Graduate Entry Medicine Mentoring at Salford (GEMMS) was established in 2015 by Prof Niroshini Nirmalan and a group of Biomedicine students with the objective of inspiring students to apply for careers in Medicine and Dentistry.

In 2019, the scheme was expanded to include post-graduate entry for Physician Associate studies with Dr Sara Namvar overseeing and co-leading GEMMS-PA. Each year as many as 30 students have taken part in elements of the mentoring scheme, with 4-5 students successfully transitioning onto Medicine or Dentistry. Many more successfully join Physician Associate courses. The mentoring for this working group is quite intense and involves close collaborative activity between staff and students with reliance upon the good will of our alumni.

Large scale events are regular and popular (e.g. Personal statement writing, mock interviews, external inspirational talks etc) attracting 100 students at a time and are usually held many times during the year. These are followed up with smaller bespoke events depending upon the needs of students at the time. Mentoring generally begins with career management support – helping students decide upon the extracurricular activities they need to engage with and providing references to hospitals for instance. There are regular personal statement workshops and personalised feedback on statements. Interview practice sessions are also a regular occurrence and often involve our valued alumni sharing their experiences. For students working towards Medicine or Dentistry, a working group of students has been established which holds regular UKCAT/GAMSAT study sessions to support preparation.

Research Careers

By Dr David Greensmith

Research careers are extremely varied, typically covering academic, industrial or clinical research but usually require the continuation of the academic pathway and  strong interest in a specific area of biomedicine.  These careers are competitive but are the literal advancement of science.

Where it starts after graduating: Most research-based careers start by securing a PhD position. You may need to undertake a Masters (preferably by research) first, but this is not an absolute prerequisite; it will depend on the level of research experience developed during your degree. For details see the recording mentioned later.

Where you can end up: There are many research-based careers in a huge range of disciplines. Broadly speaking, they fall into three areas: (1) Academic (undertaking research in a university setting), (2) clinical (for example working on clinical trials) and (3) industrial (product and process development).

Benefits of a career in this field: No two careers are the same and for most you will have a high degree of autonomy; you will heavily shape the exact course of the research you undertake and therefore your job. Successes mean a lot in research and can be incredibly rewarding. For example, you will publish your research and may become an internationally recognised expert in your field. You will likely travel the world to present at scientific conferences and in some cases pass on your knowledge to the next generation of undergraduate scientist.

Salford’s Research Careers Working Group (RCWG) seeks to facilitate undergraduate progression to research-based careers including Masters by research and PhD positions. I established the RCWG four years ago as a platform for students to engage with research and to mentor students through PhD applications. Since then, the scheme has developed, and we now have a dedicated Teams Site, student leads and a growing membership that forms a vibrant community of like-minded students.

The RCWG is suitable for all students at any level. As you progress through your degree, we’ll help you build a research-aligned CV through activities such as a regular journal club, dedicated seminars, discussion groups, learned society engagement, facilitated conference attendance, vacation scholarship and travel grant applications, research career events and scientific writing competitions. Then, when you are ready to apply for research-positions we will mentor you through the process.

On the 24th February, the RCWG hosted the inaugural “An introduction to research-based careers” symposium. Attended by around 40 students, I gave a brief overview of the PhD position then Dr Caroline Topham explained where a PhD can lead and considered the pros and cons of a research-based career. We were also joined by an international panel of scientists at various career stage who shared their experiences, advice and insight. The subsequent Q&A session was incredibly engaging. Don’t worry if you missed the symposium as it was recorded and can be accessed via the RCWG Teams site.

It’s also the first of many exciting events. Membership is free, and virtually all our activities are highly transferable; they will look good on any CV. As such, it’s well worth joining even if a research-based career is only one of many options on your radar.

Biomedical Science Careers

By Aimee Pinnington, Specialist Biomedical Scientist, and Caitlin Owen

Biomedical Scientists (BMSs) typically work in healthcare laboratory settings and carry out tests on patient samples that will usually contribute to or determine a patient diagnosis or evaluate the effectiveness of treatment. ‘Biomedical Scientist’ is a legally protected title which requires registration with the Health and Care Professions Council. To register, BMSs must obtain a Certificate of Competence from the Institute of Biomedical Science (IBMS), which is achieved by the completion of a Healthcare Science or Biomedical Science degree accredited by the IBMS, and the IBMS Registration Training Portfolio, which typically takes around 12 months to complete. It can be completed at an IBMS-accredited training laboratory (most hospital laboratories) either during an integrated or sandwich year placement, or after graduating and obtaining work in one. The Portfolio is general, therefore provides qualification to start work as a BMS in any discipline, regardless of the discipline worked in whilst completing the portfolio – although laboratory experience relevant to the discipline you wish to work in is of course desirable. Disciplines in Biomedical Science include Blood Sciences, Cell Sciences, Genetics & Molecular Pathology or Infection Sciences. Disciplines available vary with hospital size and speciality. For more detail on disciplines, registration, and BMS careers, visit the IBMS website: http://www.ibms.org

Where it starts after graduating: Highly variable depending on opportunities available at the time and whether you graduate with IBMS Registration Portfolio or not. You may enter the lab at Biomedical Scientist (BMS), trainee BMS, Associate Practitioner (AP), or Medical Laboratory Assistant (MLA) level – more guidance on this is available on the Careers Hub and BMS Mentoring Teams site. You may also choose to work in the private sector rather than NHS labs, in which case progression routes can be different.

Where you can end up: Again, highly variable! You can progress through the lab ranks, going from newly qualified BMS to Specialist and then Senior BMS. Some choose to move into lab management, some into teaching like myself, some into consultancy work etc. There are lots of details available on the Careers Hub and BMS Mentoring Teams site about alternative career routes and emerging roles, for example Patient Blood Management. 

Benefits of a career in this field: Direct impact on patient care, a constantly evolving field, working with a variety of cases which helps make everyday interesting. 

Launched in January 2020, the Biomedical Scientist (BMS)  Mentoring Scheme Teams site has proven very popular, with over 80 students joining already. The aim of the site is to provide tailored support for those looking to pursue a career as a BMS after graduation, offering: 

• Job application support, including CV/cover letter feedback and mock interview support 
• Guidance on HCPC and IBMS 
• Q&A sessions on careers as a BMS 
• Meetings with BMS staff from across the country to explore different career options 
• Access to external IBMS events (for those with e-student membership) 
• A support hub to chat with your peers about careers as a BMS 

You can join the Teams site via BB or by email.   Take a look at the resources and recordings available and get involved today to help achieve your career goals.  

Biomedicine Careers Hub Update

By Dr David Greensmith

The “Biomedicine Careers Hub” I wrote of in the previous issue continues to grow from strength to strength. The hub (which can be accessed via the “communities” area of Blackboard) is now heavily populated with career-related resources. You will see several activity spaces, each associated with a particular high-level career area:

• Biomedical scientist and pathology lab
• Research-based careers and progression to PhD / Master by Research
• Taught masters
• Teaching
• Graduate entry medicine, dentistry and physician’s associate
• Biotechnology and industry
• Microbiology and public health
• Scientific communication, writing and outreach

Each space is managed by a member of staff who is an expert in the field and are packed full of useful and career-specific resources. Remember, each space represents a considerable breadth of distinct pathways and the list certainly isn’t exhaustive. Indeed, if you feel a certain career group isn’t represented, let us know. On the hub, you will also find general activity spaces which contain career-spanning resources such career events, placements and CV enhancing opportunities.

Remember, you can use the hub in two ways: (1) to research career options and (2) to make yourself more employable by engaging with the many extra-curricular activities that feature on the site. It’s a highly dynamic resource and will constantly grow and develop with new content so do access it on a regular basis to see what’s new.

The leads of certain career groups have established parallel MS Teams sites for further career-specific mentoring and support. To gain access to any of these Teams sites, go to the Careers Hub or simply contact the associated academic lead. These academics have given an overview of each career and its career hub in other articles.

Prophage-host interactions: lifting the curtain on Pseudomonas’ puppet masters

Dr Chloe James in conversation with Prathyusha Vishwanthan

Humans have been aware of bacteriophages as major players in the microbial world for over 100 years. Their most widely recognized feature is their ability to infect and kill specific bacteria, but they are also known to provide some beneficial characteristics to their bacterial host. Apart from a few famous examples, this aspect of phage biology has been largely neglected and the temperate phage-bacteria relationships are not fully understood. Dr Chloe James, a senior lecturer in Medical Microbiology at the University of Salford, has been very curious about this dynamic and has been working on this for a while.

Recently, Dr  James  started a new project funded by the BBSRC, which aims to observe how bacteriophages affect the behaviour of their bacterial host. It  will focus on a notorious opportunistic bacterium, Pseudomonas aeruginosa, a common cause of respiratory infection in cystic fibrosis patients.

Prathyusha Viswanathan interviews Dr Chloe James about her unique and interesting project:

It is quite a different yet interesting topic. How did it all start?

A few years back, I worked on a project examining cases of cystic fibrosis patients who were chronically infected with the Liverpool Epidemic Strain of Pseudomonas aeruginosa. The team had previously found this stain to cause much more severe disease than other strains and to spread from patient to patient, which seemed very unusual.

After sequencing the genome, they found several never-seen-before co-existing prophages. This is where I came in. I regularly monitored phage and bacteria in the patient’s sputum samples for over 2 years. The most notable finding was that these phages were always active and present in abundance. But we could not find any association between the phages and patient condition or antibiotic treatment.

So, this got me extremely curious, like wow, even though the phages are actively killing their bacterial host, the bacteria are still keeping hold of them which means that they must be helping the bacteria in some manner and this point made me determined to find out what they are actually doing. So, I worked with colleagues [Dr. Ian Goodhead and Dr. Heather Allison] to design a project that would better understand how the phages and bacteria affect eachother’s biology, the hypothesis being that temperate bacteriophages do so much more than what we know and at the moment. I think that they pull all kinds of strings and regulate bacterial behavior in different ways.

The BBSRC awarded us funding for 2 postdoctoral researchers to work full time on the project, but we also have some linked projects that are being explored by research students at Salford and Liverpool University.

What achievements have you made so far?

Some key findings of our work are that for one, each of the LES phages seems to be affecting the fitness of the P. aeruginosa host differently and depending on environmental conditions; secondly, together, these temperate phages seem to facilitate rapid evolution of their bacterial host contributing to their adaptation to the CF lung environment; lastly, we think that phages may have an important role in the competitiveness of the LES in CF lungs by acting as anti-competitor weapons (killing other P. aeruginosa strains). But this new project will delve much deeper into the mechanisms of interaction between these intriguing microbial partners. We have published a lot of this work.

These are two complex creatures; you may have noticed many  interactions – have any been particularly unexpected or peculiar?

Yes, that’s true. We are uncovering all kinds of interesting nuggets to follow up on. So far, the most striking discovery is the evidence that the phages are interacting with each-other. This means that the bacteria behave differently depending on which phage they are infected with, and in cases when multiple prophages co-exist together, we observe a completely different behavior. Of course, we also suspect that the bacteria is affecting the biology of the phages. Seeing how the phage infection progresses differently in other P. aeruginosa host strains has helped me direct my thinking in more broader dimensions.

What have been the most recent outputs from the project?

Grace Plahe, a Salford MRes student, presented her work on how LES phages affect bacterial growth and virulence at three different conferences last year. One of her abstracts has been published, and some of her preliminary data helped us to secure the bigger project funding we have now. Since then, two postdoc researchers have been employed on the project, and they will present their preliminary findings on phage-phage interactions and phage genome annotation at the next Microbiology Society annual conference.

What are the upcoming stages of research?

So, our latest funding is to run for 3 years and there are plenty of upcoming tasks on our list. Firstly, our aim is to thoroughly profile the infection cycles of each phage under a range of environmental conditions, and monitor changes in the expression of genes that reports the key stages of the process. We will then conduct a huge transcriptomics experiment which will map global gene expression of bacteria with and without their phage partners. This will show which phages  are regulating which bacterial genes and vice-versa.

We will also perform experiments by exposing the bacteria to both favourable as well as challenging conditions, so that this will help us to identify why the bacteria is keeping hold of so many elements that could so easily kill it and most importantly, we will also construct a series of mutants and perform functional assays to confirm our theories about how these phage puppet masters are pulling the strings.

it seems that your findings have a wide scope in research and  could help thought processes in other fields, leading to new  technologies; yet temperate phage research is rare and has not yet been given much importance. What do you have to say about this?

Very true, I agree. This aspect of phage research has not been given much attention. Most of the research is concentrated on the destructive nature of bacteriophages towards specific bacteria for developing antibacterial treatments. There is a lot of renewed excitement in that area at the moment, with real potential to improve treatment of infections caused by antibiotic resistant bacteria. Whilst the beneficial effects of prophages on bacteria have not been ignored, the scale of this has been grossly underestimated. There is so much more left undiscovered. There are relatively few published findings on the regulatory properties of temperate phages and yet there is a huge amount of genome evidence to show us that ~60% of the sequenced bacterial strains carry prophages in their genomes, and even more  tantalisingly, over 70% of most prophage genes are of unknown function. We know they are present everywhere, and that bacteria are keeping hold of them even though they can present a considerable cost, but we don’t know what they are doing!

I am sure there are many exciting crossroads for this type of research, and you were absolutely correct, this type of research would also help other research fields to understand the pathology of disease better and could inform completely novel approaches to patient treatment and management. In fact, CRISPR systems were actually invented by bacteria, in order to protect them against bacteriophage attack! So, studying phage-bacteria interactions can indeed trigger revolutionary new fields of research and I hope that some of our findings will lead to new thinking in all kinds of areas that I haven’t even considered.

For the Love of Global Health: Ongoing University of Salford Microbiology Research in Uganda

By Prof. Richard Birtles 

In late 2015 I got an email from Louise Ackers, a Professor in the Health School, asking if there were any microbiologists at Salford University. I told her, yes, there were a few, including me and my colleague Dr Chloe James. Looking back, this was yet another moment of serendipity that changed my life – another “bit of luck out of the blue” that serves to remind me that just when you think life is getting predictable, there’s always a surprise just around the corner. Louise was looking for some help with a project she was planning in Uganda focused on educating hospital staff to improve antimicrobial stewardship.  

Six months later, Chloe and I were in Fort Portal, the biggest town in western Uganda, washing our hands like fury in front of groups of doctors and nurses to illustrate a good way of controlling transmission of Staphylococcus aureus infections. By this point we had learnt a lot about the appalling impact of infection (particularly sepsis) on maternal mortality in Uganda and we wanted to try and do something to help.  

We arranged for the regional hospital to collect S. aureus clinical isolates for us and, with the help of a new PhD student, we set about characterising these to see how they were related to one another and the extent of their resistance to antibiotics – hoping to get a better understanding of where mothers pick up infection from and how best to treat  infections. This work involved sequencing bacterial genomes and, with the help of my colleague Dr Ian Goodhead, we were able to do this in collaboration with microbiologists at Makerere University in Kampala as a way of transferring expertise in genomic techniques that are well-established in the UK to Uganda.  

Staff at Fort Portal Regional Referral Hospital use VR developed by Chloe and others at Salford University to learn about antimicrobial stewardship. 

We used our free time in Fort Portal to explore some other avenues – I’m interested in tick-borne infections of livestock, so we had a day-trip to nearby farms to pull ticks off cows (later tested by an MSc student) and Chloe had us collecting chicken poo as part of a project on the epidemiology of the food-borne zoonotic pathogen Campylobacter jejuni.  

Chloe’s PhD student, Paz, collecting faecal samples from Ugandan chickens to screen for Campylobacter jejuni and other zoonotic pathogens. 

Fort Portal is also the “home” of a UK/Uganda charity called Knowledge for Change (K4C). K4C has been offering placements for Salford University nursing and midwifery students for several years and we were very keen that they expand their offering to include Biomed and HBID students. It took a while to get things sorted, but the first group of BMS and HBID students went out to Fort Portal with Chloe in June 2018 and had a wonderful, life-changing month-long experience embedded in local microbiology, parasitology and haematology services. Here’s what BMS student Adrian Beck said: “This placement had a very positive impact on my personality. The most important thing I noticed is Ugandans have so little [materially] but are still so happy; I am grateful now that I have roof over my head and my good health!”. 

Our work on S. aureus as a cause of maternal sepsis and other hospital-acquired infections started to yield results (https://www.biorxiv.org/content/10.1101/2020.11.20.371203v1), and Chloe returned to Fort Portal in January 2020 to share these results with hospital and public health staff. She used virtual reality kits to help her deliver messages about antibiotic resistance and how it develops. Through continuing collaboration with Louise Ackers this work also contributed to improved antimicrobial stewardship both locally and nationally. 

An infectious control ( hand hygiene) class at Kibiito Health Centre.  

In late 2017 we were chosen to showcase the work we’d been doing in Fort Portal to a delegation of academics from the University of Gulu who were visiting Salford University. Gulu is in northern Uganda, a region devastated by civil war in the 1990s and 2000s and now accommodating hundreds of thousands of refugees from South Sudan and the Democratic Republic of Congo. The University in Gulu is new and very keen to establish collaborations with Institutions that have strong global health research, thus in January 2018 Chloe, Ian and I made a reciprocal visit to Gulu aiming to develop these collaborations. 

We had an amazing, exhausting trip, which included me addressing prisoners in a remote jail about body lice and the infections they transmit, and encounter with children suffering from the terrible “nodding disease”, the cause of which remains a mystery. Ian and one of his PhD students were able to carry out field work collecting tsetse flies, which transmit sleeping sickness. We established links with scientists working on black flies that transmit river blindness and are now working together exploring the microbiomes of black fly guts and their possible impact on Onchocerca volvulus transmission.  

The one person we didn’t meet in Gulu was Dr Richard Echodu, the Director of Gulu University’s new multifunctional research laboratories, who was away in Kampala. However, in early 2020 yet another moment of serendipity led to our working together on the biggest Salford-Uganda collaboration to date. Richard and I were talking about a grant application to support the black fly microbiome work mentioned above, when I mentioned COVID-19.  Richard spoke passionately about how unprepared Uganda was for the pandemic and we both agreed to look out for funding that might give us the opportunity to contribute the country’s response to the virus. A week or two later, Ian found a call for the UK Government through its Global Challenges Research Fund that seemed to fit the bill. What followed was pandemonium as Ian, Richard and I raced to submit our application (at the same time as converting all our teaching to online and teaching students as befuddled by all the changes as we were), but submit we did, and a month later we got the surprising news that we’d been funded.  

The project started last August and under the management of the magnificent Dr Judy Mwangi (who just completed her PhD at Salford University) with fantastic support from Louise Ackers and many other people, we are now six months in and still standing. Working in two countries during the pandemic has thrown up many barriers but this week our diagnostic laboratory opened for business with the approval of the Ugandan Ministry of Health. We now aim to test at least 25,000 people for SARS-Cov2 infection in the next few months and to compliment this with genome sequencing by the summer.  

Me playing a rather passive role in collecting ticks off local cattle. Doing most of the work is my ex-Phd student Jess and Philip (right), a Regional Veterinary Health Officer. 

We’re particularly interested in the impact the virus is having on refugee communities and how the epidemiology of infections might be shaped by risk factors quite different to those recognised in the UK, such as age and obesity. Most Ugandans are young and not fat, but they are far more likely to be carrying parasites or be malnourished than Salford residents. Hopefully, this time next year, we’ll have some answers and we’ll also have helped Gulu University establish itself on the national stage as a centre of molecular microbiology research excellence because the need for such expertise will not go away with COVID19.                   

So, as far as this story goes, we’re nowhere near the end, but maybe we’re at the end of the beginning. There will undoubtedly be many opportunities for oldies like me, Ian, Chloe and Louise, who have loved global health for many years, but there are also opportunities for those just starting out; those who recognise that the relevance of biomedicine and bioscience extends way beyond the boundaries of Salford, or Manchester, or the north-west, or the UK. There’s a big world out there waiting!  

K4C placements are available (again) from September 2021 and are open to all, regardless of whether you are still a student or not. For more information, check out their website, www.Knowledge4Change.org. 

Does our gut microbiome affect the way we think?

By Bruce Veloso

Trillions of microorganisms inhabit the human body at any one time, collectively known as the microbiome. The largest proportion of the microbiome (more than 100 million microorganisms) is in the human gut – up to 100 times the number of eukaryotic cells in the body¹.

Dietary content directly affects the composition of the gut microbiome. For example, it was shown that the composition of gut bacteria present in Europeans is significantly different from that of Africans, a phenomenon which may be attributed to the differences in their regular eating habits². It was observed that the gut bacteria present in Europeans was mainly composed of the Bacteroides enterotype. In contrast to this, the African gut microbiome was mainly composed of Prevotella enterotype.

Furthermore, Wu et al. observed from examination of stool samples from 98 people that Bacteroides spp. are mainly associated with a diet high in animal fat, whereas Prevotella spp. are closely associated with a diet high in carbohydrates².

Zhu et al. explain that after many years of co-existence, some gut bacteria – including six predominant phyla of Firmicutes, Bacteroidetes, Proteobacteria, Actinomycetes, Verrucomicrobia, and Fusobacteria – have developed a ‘symbiotic relationship’  with humans by forming a large portion of the gut microbiome and helping us with a multitude of tasks such as digesting food and preventing growth of pathogenic bacteria¹.

However, the influence of the gut microbiome extends far further than previously believed. The gut and the brain form the ‘gut-brain axis’, where changes in either organ directly impact the other. Experimental evidence suggests that the multiform interactions between the gut and brain likely contribute to several neurological and mental illnesses, such as depression, Alzheimer’s disease and schizophrenia¹.

Here are a few examples:

Microorganisms in the gut can affect the brain of the host organism by regulating the brain-derived neurotrophic factor (BDNF, a nerve growth agent which supports and differentiates neurons) and N-methyl-D-aspartate (NMDA, an amino acid that acts as an agonist, copying the action of glutamate, a neurotransmitter) receptors¹. Changes in BDNF expression are associated with cognitive dysfunction of patients suffering from schizophrenia¹. Interestingly, when the expression of NMDA receptors in a host is enhanced, symptoms are relieved and cognitive ability improves¹.

Additionally, studies have shown that the microbiota can influence the central nervous system by altering hippocampal neurogenesis (process in which new nerve growth takes place in the hippocampus)¹. According to Zhu et al, the hippocampus and lateral ventricle areas of the brain have an important function in learning and memory and therefore can influence the pathogenesis of neurological disorders and symptoms in conditions such as epilepsy, depression, Alzheimer’s disease and Parkinson’s disease¹.

Intriguingly, 95% of serotonin, a neurotransmitter mainly associated with mood and emotion, is produced in the gut, and microorganisms present in the gut may be essential for its production: in sterile mice, serotonin production was reduced to 60%¹. Certain compositions of the gut microbiota may promote the development of depressive disorders. It is fascinating to speculate that we may be able to treat depression and related health conditions using specific food types or even by faecal replacement therapy.

References

1.  Zhu X, Han Y, Du J, Liu R, Jin K, Yi W. Microbiota-gut-brain axis and the central nervous system. Oncotarget. 2017;8(32):53829-53838. doi:10.18632/oncotarget.17754
2.  Wu GD, Chen J, Hoffmann C, et al. Linking Long-Term Dietary Patterns with Gut Microbial Enterotypes. Science. 2011;334(6052):105-108. doi:10.1126/science.1208344

Parasites: Friend or Foe?

By Muhammed Amla

Accounting for nearly 40% of all species on Earth¹, parasites are organisms which survive and reproduce by forming symbiotic relationships with other organisms (known as hosts in this relationship) which benefit the parasite and generally harm the host. Many parasites cause death and disease, but they also have helpful roles in health, industry, crime, and agriculture.

While they are not holidaying in your guts or using their host as live cocoons², parasites can actually be greatly beneficial, from improving agriculture to triggering major evolutionary changes.

Farming

With an estimated 20-40% of global agriculture lost to insects, parasites may offer a far more effective solution than damaging farmlands with costly pesticides. Parasitoids are insects behaving like parasites that kill their hosts in the process³, with many naturally preying on crop pests. One example is the Aphidius ervi, a parasitic wasp that lays its eggs in aphids, turning the aphids into a parasitised mummy⁴. Within 2 weeks, the offspring eat their way out of the aphid, searching for more aphids and perpetuating the cycle.

UK rapeseed oil production is hindered by midges. Several wasp parotoids, such as the Platygaster subuliformis attack these midges, killing up to 75% of their larvae⁵. This non-chemical control of pests not only reduces damage to farmland, but also to health of the farmers. Indeed, it is widely accepted that long-term pesticide exposure is linked to Parkinson’s disease, asthma, depression, ADHD, anxiety, and cancers⁶.

Boosting the Immune System

Being infected is not always a terrible thing. In some cases, it can supply more benefits, such as increased protection in hosts from infection by pathogens. Enterococcus faecali, a mildly pathogenic bacteria living in worms, can evolve rapidly to protect their hosts from more lethal infections⁷. This blurs the line between parasitic relationships, where the parasite feeds from the host while causing harm, and mutualistic relationships, where the parasite and host both provide benefits to each other.

There are two forms of protection a parasite can provide to its hosts: resistance, and tolerance⁸. Parasites that provide resistance reduce the likelihood of other species infecting. For example, bacteria in the gut resist the invasion of non-native species. This specific example is also known as colonisation resistance⁹. Meanwhile, parasites providing tolerance reduce the harm of another invading species. For example, when Monarch Butterfly Larvae are inoculated with Ophryocystis elektroscirrha, a virulent protozoan parasite, they have a higher chance of survival when attacked by the lethal parasitoid fly, Lespesia archippivora, than if exposed to the parasitoid alone (fig. 1)¹⁰.

Figure 1: Monarch survival to adulthood when exposed to the protozoan parasite, fly alone, and the protozoan and fly combined¹⁰

Research has shown that when infected with an intestinal worm, the number of lymphoid follicles (microscopic compartments storing B cells, which produce antibodies against pathogens) in mice increased.

The body naturally produces more B cells to increase antibody production in response to an infection, but it does not typically increase the number of lymphoid follicles. However, upon infection with intestinal worms, a cytokine molecule (IL-4) is produced which stimulates B cells to produce lymphotoxin. This then interacts with stromal cells, which produce another cytokine (CXCL13) stimulating follicle production in the lymph nodes¹¹.

B cell follicle formation was previously thought to only occur during the post-natal period (immediately after birth), but this research showed that this process can also occur in adult mammals in the event of a worm infection¹². While it is not recommended to use intestinal worms directly to boost the immune system, it is important to note that they do strengthen the immune system uniquely and this may shape novel research and ultimately treatment strategies in the future.

Another study involving amphibian hosts and trematode parasites displayed how parasite richness not only dampens pathogen transmission, but also inhibits the spread of Ribeiroia ondatrae, a deadly parasite which causes limb malformations in amphibians¹³.

Driving Evolutionary Change

While there are a wide variety of other factors that influence evolutionary change and diversity, it can be said that parasitic organisms could also have played a key role. It is important to note that the following are mainly theories, with many other factors contributing towards evolutionary change, as opposed to exclusively or mainly parasites.

It is hypothesised that parasites drive organisms to become more diverse and complex. The constant evolutionary arms race between the two promote increased defences by the host against the parasite, meanwhile the parasite increases its effectiveness to infect its host. Using computer programs and parasitic programs in a simulation, it demonstrated how diverse lineages arise from the coevolution of hosts and parasites, encouraging then to form complex traits¹⁴. Similar demonstrations with bacteria¹⁵ also indicate the importance of parasites, showing a noticeable effect on population dynamics and evolution.

Parasites and Sex

Another hypothesis is parasites could have influenced the existence of sexual reproduction. One advantage gained, from shuffling genes and producing genetically diverse offspring, is surviving parasites more effectively. The presence of parasites can encourage the constant genetic turnover and force hosts to keep evolving¹⁶.

An experiment conducted with worms and parasites displayed how selfing populations were wiped out within 20 generations, as opposed to outcrossing populations which persisted throughout the experiment¹⁷. Male snails also start to disappear from the population in areas where parasites are rare, favouring asexual reproduction over sexual, due to the substantial costs of sexual reproduction¹⁸.

Parasites and the Brain

Certain parasites have been known to manipulate host behaviour, for example Toxoplasma gondii, which diminishes a rodent’s predator evasion around cats, turning it into an easy meal. Other examples include rabies, and some sexually transmitted pathogens have been known to influence sexual behaviour. It can be suggested that the human central nervous system has evolved to be incredibly complex as a protective countermeasure against parasites that influence behaviour.

The blood brain barrier is a first line defence from pathogens and toxins present within the bloodstream¹⁹. In the constant arms race, there are other parasites that have evolved to pass the barrier using white blood cells and monocytes as a mode of transport²⁰. Some parasites can cleverly manipulate behaviour externally, for example Toxoplasma gondii increases dopamine, a behaviour altering substance²¹. Others can secrete different hormones and activate specific immune responses to manipulate their host to complete their life cycle or leach resources.

Another countermeasure to protect the brain against behavioural changes by parasites is an increase in the amount of neurochemicals required to induce responses. Some parasites release neurochemicals to alter behaviour, the more required to create a response, the greater metabolic cost on the parasite. Due to the generally large size difference between host and parasite, it renders the attack ineffective. The relentless pressure from the increasing brain size through the course of human evolution could have led to parasites adopting alternative strategies²².

Rather than the parasites directly attaching and physically affecting the brain, some parasites like Ophiocordyceps unilateralis almost never touch the brain, yet precisely control insect behaviour²³.

Another advantage of increasing brain size is developing higher levels of protective complexity, meaning they can take more damage while maintaining normal functionality and behaviour. For this reason, mind controlling parasites are more commonly seen in insects. Increasing neuro-signalling complexity, with the use of a range of receptors, neurochemicals, and timed pulses, closes off a parasite’s attacking options. While more complex signals have an increased metabolic cost, it is disproportionately more expensive for parasites, forcing other means of manipulation²².

References

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