THE B-WORD
0
THE B-WORD
Contents Editor’s Notes Visit to the Centre of Snakebite Research and Intervention The Rare Earth Hypothesis: Are We Really Alone in the Universe? The Curse of Evolution and Lineage – Cost-Benefit Analysis The Impact of pH on a Named Biological System Application of Nanotechnology to Treat Biofilm Infections Interesting Fact
2 3 6 9 14 15 19
1
THE B-WORD
Editors' Note Dear Readers, We are thrilled to present the first of three editions of the B-Word Journal this academic year. From a hugely debated topic in astrobiology to the practicalities of handling snakebites, this debut collection offers a glimpse into the diverse narratives our community brings to life. We're excited for you to explore the biological wonders captured in these pages. Thank you for joining us on this scientific journey and the beginning of an exciting triad! Warm regards, Holly and Ester Editors, B-Word Journal
2
THE B-WORD
Visit to the Centre of Snakebite Research and Intervention By Jake Abel-Brown During my work placement at the Liverpool School of Tropical Medicine, we were asked by our Lab Manager what we would like to do as a career, the other 2 students on work placement there both said that they wanted to go into Biomedical Sciences. So, when I said I wanted to study venomous animals, needless to say she was a bit surprised. However, she then presented me with a rare opportunity, a chance to tour their Centre for Snakebite Research and Intervention (which the public are not allowed to visit). As a lifelong fan of all things venomous, I jumped at the chance. I got given a disclaimer that read along the lines of ‘These animals are extremely dangerous and if you do not follow instructions it could lead to injury/death’ which oddly enough just made me more excited to go there. Upon entry to the CSRI, we were greeted with posters about venom composition and symptoms, which the Herpetologist (Herpetology is the study of reptiles and amphibians) Edouard Crittenden talked through in great detail, some of the diagrams can be seen below.
After seeing some images of real snakebites (which I have decided to leave out of this article as I fear they might be too squeamish for some readers) he showed us a snake in the genus responsible for the most human deaths in the world, Echis ocellatus. A snake that has a maximum length of only 65cm that causes a disproportionate number of human deaths in its geographical range. This is because of two main factors: 1. Their venom is far from harmless; it contains snake venom metalloproteinases (SVMP’s) and phospholipase A2 (PLA2). These components cause a combined effect of haemorrhages, localised necrosis (cell death) and anticoagulant effects (by using up all fibrinogen in the blood by creating micro clots). All of these symptoms combined make for a thoroughly unpleasant experience. However, SVMP’s and PLA2 are 2 of the most common components in venom of the snakes in the family Viperidae, so what makes this viper particularly detrimental? 2. Location. The issue with the genus Echis is down to where they reside, tending prefer rural areas in particular, farmland far away from the nearest hospital. This happens to be where farm workers are out in the fields, wearing sandals if they are lucky, working the land. Due to Echis’ highly successful camouflage, people do not spot them until they unfortunately step on or near them, causing the snake to bite. As the victim would be so far away from hospital, they can only try local remedies for snakebites and hope for the best. If they do manage to get to a hospital in time, antivenom is extortionately expensive in low-income countries, making a full recovery unlikely as most workers wouldn’t be able to afford enough antivenom. This is the exact problem that the CSRI is trying to combat by researching ways to make antivenom as cost efficiently as possible so they would be able to send it out to these less fortunate countries to try and mitigate the effect of snakebite related injuries. Being a world-
3
THE B-WORD renowned institute, they make it their mission to contribute to the global issue, specifically in SubSaharan Africa due to the amount of LIC’s that suffer from snakebites. Following the talk on Echis ocellatus, we entered one of the main snake rooms, which had 18 large vivariums in it. As we walked in, there was a forest cobra (Naja melanleuca) already hooded up and ready to strike in its vivarium pictured below.
This was the first room I had been in were every single one of the animals in said room had more than enough potency to kill me. It was exhilarating. In this room as well as the Forest Cobras, there were Snouted Cobras (Naja annulifera), Mozambique Spitting Cobras (Naja mossambica), Puff adders (Bitis arietans), Black Mambas (Dendroaspis polylepis) and their lesser-known cousin the Western Green Mamba (Dendroaspis viridi). A few of the cobra’s bluff struck at us but what I found most interesting was that the most potent of the snakes in the room, the mambas, where a lot calmer than the cobras. Edouard went on to explain that although a cobra bite could very well still be fatal if left untreated, the mamba’s venom is a lot more lethal, and because they are aware of this, they generally don’t need threat displays because most animals know to avoid them, hence their lack of aggression whilst in vivariums. Edouard pointed out that on the tank of N.mossambica had what looked like water marks on the inside of the glass. This turned out to actually be what was left of the venom when the snake had spat at Edouard and the other Herpetologist as they were doing maintenance on the other snake’s vivarium. After he had answered everyone’s questions about
these snakes, we went into the second snake room where they house their smaller/less active species, this includes but isn’t limited to Gaboon vipers (Bitis gabonica), various vipers in the genus Echis, 2 Bushmasters (genus: Lachesis) and the snake with the most potent venom in Africa; the Boomslang (Dispholidus typus) which is a rare case of a snake in the family Colubridae having medically significant venom. The in-house boomslang is pictured below.
Edouard then went on to tell us a story about Karl Patterson Schmidt who, in 1957, was bitten by a juvenile boomslang and instead of trying to remedy the bite, he documented his symptoms during the last 24 hours of his life. Edouard said that deaths caused by boomslang envenomation are so rare that whenever someone is killed by one, it is very likely that someone will write a scientific journal on it. Less than 10 people have died from boomslang venom although the venom is the most potent in Africa. This low number is down to the boomslang’s behaviour as they are a very shy snake and tend to avoid humans at all costs. People only get bitten when they try to handle them or kill them. After this, we had a look at my all-time favourite animal, the Gaboon Viper (B.gabonica). One of the heaviest bodied snakes, with 5cm long fangs and the largest venom yield of any viper.
4
THE B-WORD the resident herpetologists regularly assist the police when seizing venomous creatures. I noticed that on the floor in the room to get some exercise as they are not deadly, don’t tend to be aggressive and are quite slow moving.
B.gabonica venom’s main component serine proteinase, metalloproteinases and PLA2. This combination of venom proteins results in huge amounts of localised necrosis and disruption the nervous system causing organ paralysis resulting in a painful death if left untreated. However due to the reclusive, lethargic nature of this snake, bites are rare and significant envenomations are rarer. Edouard then directed us to a few Variable Bush Vipers (Atheris squamigera) in the corner. He went on to tell us that these vipers in particular had been seized at customs and given to the CSRI as they are the only facility in the UK that can keep that number of venomous animals and that All in all it was a rare and thoroughly enjoyable experience that I am extremely grateful for.
However, 1 day, after lunch, Edouard came back into the room, and he could not find one of them. For 20 minutes he searched worrying that it had escaped and was freely roaming the building. This was until he heard some scratching noises from above. It turns out that the Gila monster had climbed 2 metres up the enclosure rack and was walking about on top of them. Needless to say, that was the last time they roamed the room unsupervised. The tour was finished by the Lead Herpetologist, Paul Rowley, showing us some videos of snake venom extraction where the snakes would bite down onto a thin membrane covering a collection dish. Some snakes like E.ocellatus only needed 1 person to hold but the larger heavier snakes like B.gabonica required 2 people to hold as it is a powerful and fast striking snake.
5
THE B-WORD
The Rare Earth Hypothesis: Are We Really Alone in the Universe? By Ruby Allen-Brown
Uncanny, unsettling, and unknown: the Rare Earth Hypothesis refers to the proposition that although microscopic, simple organisms may be common in the Universe, the emergence of more complex and intelligent life requires a demanding combination of astrophysical and biological conditions that are simply unconventional throughout the Universe.1 The argument is based on several foundations, including the absence of extraterrestrial signals of life, the contradiction between the vast number of nearby habitable planets but no evidence of extraterrestrial civilisations, and several additional factors. The scarcity of complex life as a result of the Rare Earth Hypothesis is a topic debated by astrobiologists worldwide, and with the continuous ongoing advancements within the field, researchers are bravely anticipating the next breakthrough.
characteristic that Earth does is so close to zero that researchers can say it is almost unfeasible. The hypothesis does not counter the existence of simpler, microscopic life forms on other planets, as they should still be able to develop without much difficulty in certain environments. However, the emergence of more complex life may require an extensive list of criteria to be met for it to evolve.
One argument in favour of the Rare Earth Hypothesis regards the unique set of conditions that makes Earth hospitable for life. These include the sun’s stable energy output; the position of Earth in the Milky Way; Earth’s magnetic field and the Moon’s role in regulating the planet’s axial tilt.2 Each factor listed plays a significant role in ensuring the survival and development of life. For example, Earth’s magnetic field not only has plate tectonics that stabilise the climate, but also shields the planet from incident cosmic radiation that is harmful to life. The main principles of this argument are based on the idea that the probability of another planet also being located within the habitable zone of its star and possessing every
Perhaps to understand the evolution of complex life on Earth, the history of the planet should firstly be examined. The dinosaur extinction is a particularly pivotal event as it eliminated almost all dinosaurs, but left mammals alive. From this event, we can draw three conclusions, the first being that large reptilian species always come before mammals and are always more dominant. One of the reasons being that egg laying species evolve and adapt rapidly as they can have magnitudes more offspring.3 Secondly, mammals naturally create civilisation if they are dominant in an ecosystem: mammalian parents are vulnerable throughout pregnancy and their offspring require care and attention when they are young. Many argue that this stage of parenting and care is what led to complex social structures and eventually intelligence. Finally, dinosaurs and other reptilian species likely cannot create civilisation given any amount of time. Dinosaurs abandoned and buried their eggs, suggesting they lacked intelligence; they were Earth’s ruling species for 165 million years4 and yet could not create civilisation. Contrarily, it only took mammals 65 million years to evolve and create the complex and intelligent society
1 Williams, M. (2020) Beyond “Fermi’s Paradox” IV:
3 Clarke, J. (2022) “Rare Earth” Solves the Fermi Paradox
What is the Rare Earth Hypothesis? Universe Today [Online], Beyond "Fermi's Paradox" IV: What is the Rare Earth Hypothesis? - Universe Today (Accessed 08/11/23). 2 The Rare Earth Hypothesis: Assessing the Scarcity of Complex Life in the Universe (2023). New Space Economy [Online], The Rare Earth Hypothesis: Assessing the Scarcity of Complex Life in the Universe | New Space Economy (Accessed 10/11/23).
+ Earth is likely the only Civilization in the Observable Universe [Online], “Rare Earth” Solves the Fermi Paradox + Earth is Likely the Only Civilization in the Observable Universe by Jobe Soffa Clarke :: SSRN (Accessed 13/11/23). 4 When did dinosaurs become extinct? (2023) USGS [Online], When did dinosaurs become extinct? | U.S. Geological Survey (usgs.gov) (Accessed 13/11/23).
6
THE B-WORD present in humanity today. A myriad of astrobiologists criticise the Rare Earth Hypothesis, arguing that the concept is anthropocentric* and egotistical. Given the extensive size of the Universe, the idea of Earth being completely unique could be described as unconvincing. Furthermore, recent data from Kepler has suggested there are an abundance of potentially habitable exoplanets in our galaxy alone. What’s more, researchers determined that there is a 95% chance that one of these Earth-like planets exists within just 20 light years from our solar system.5 Although it is highly unlikely that every Earth-like planet will host complex life, it is reasonable to conclude that a significant proportion of them should have the necessary conditions for the development of such life. Even exoplanets with characteristics that may oppose Earth’s could still be suitable foundations for the emergence of life; recent research regarding extremophiles* and potential biospheres* on other celestial bodies suggests that complex life may not require Earth-like conditions to develop. Furthermore, many critics argue that those in support of the Rare Earth Hypothesis have not considered the vast size of our universe: even if complex life were to develop elsewhere, we may not ever be able to confirm its existence due to the sheer distance between the two civilisations. As the universe expands, the distance between galaxies will only grow further, making detection progressively more arduous. Communication attempts with other civilisations proves more difficult the greater the distance between them. If advanced civilisations beyond the observable universe* exist, it is highly likely that we will never know of them. The Great Filter is a concept that tries to explain the Rare Earth Hypothesis by arguing that every civilisation ultimately faces a barrier or filter to its own survival.6 It is unknown whether humanity has already surpassed this filter. For example, if the filter was the formation
of water or simple microbial life, humanity would have already overcome the Great Filter. Whereas if the filter came later and was related to AI or nuclear weapons, the filter may represent an obstacle that may pose a threat to humanity in the near future. Although it offers an explanation into why humanity is yet to discover complex life on another planet, the Great Filter is still ambiguous in the fact that we do not yet know what exactly the filter may be. On reflection, the Rare Earth hypothesis, although it offers an interesting perspective, seems unlikely when the size of the universe and the inability to communicate with galaxies outside our local group are fully considered. As astrobiology is a new and growing field of research, the Rare Earth hypothesis does provide criteria that may be useful in classifying complex life if we do come across it in the future. A prescient example is the set of conditions that make Earth a habitable planet: the sun’s stable energy output; the planet’s axial tilt; and plate tectonics all contribute to Earth’s suitability for the development of life. By contemplating which conditions are absolutely necessary for life’s formation, astrobiologists may be able to better determine which exoplanets are more likely to be home to complex life. Furthermore, contemplation of the Rare Earth Hypothesis could also aid in the classification of consciousness and what exactly makes humanity complex. Overall, while the Rare Earth Hypothesis may provide useful insight into astrobiological concepts, the plausibility of it seems unlikely, with many astronomers arguing that they simply do not yet know enough about the age and structure of the universe to reach a definitive conclusion. Therefore, ruling out the possibility of extraterrestrial life so early could be seen as both illogical and unjustified.
5 Williams, M. (2020) Based on Kepler Data, There’s a
6 Whitt, K. Byrd, D. (2022) What is the Great Filter, and
95% Chance of an Earth-Like Planet Within 20 LightYears [Online], Based on Kepler Data, There's a 95% Chance of an Earth-Like Planet Within 20 Light-Years Universe Today (Accessed 15/11/23).
can we survive it? [Online], What is the Great Filter, and can we survive it? (earthsky.org) (Accessed 19/11/23).
7
THE B-WORD
Glossary Anthropocentric: considering humans and their existence as the most important and central fact in the universe. Extremophile: an organism that is able to live in extreme environments, for example in regions of extreme temperature, pH, or chemical concentration. Biospheres: a region of a planet that can sustain life. Observable universe: the region of space that it is theoretically possible for us to observe. Bibliography Clarke, J. (2022) ‘Rare Earth’ Solves the Fermi Paradox + Earth is likely the only Civilization in the Observable Universe. Available at SSRN: [https://papers.ssrn.com/sol3/papers.cfm?abstract_id=number] (Accessed 13 November 2023). Whitt, K. and Byrd, D. (2022) What is the Great Filter, and can we survive it? Available at EarthSky: [https://www.earthsky.org/what-is-the-great-filter-can-we-survive-it] (Accessed 19 November 2023). Williams, M. (2020) Based on Kepler Data, There’s a 95% Chance of an Earth-Like Planet Within 20 Light-Years. Available at Universe Today: [https://www.universetoday.com/based-on-kepler-datatheres-a-95-chance-of-an-earth-like-planet-within-20-light-years] (Accessed 15 November 2023). Williams, M. (2020) Beyond ‘Fermi’s Paradox’ IV: What is the Rare Earth Hypothesis? Available at Universe Today: [https://www.universetoday.com/beyond-fermis-paradox-iv-what-is-the-rare-earthhypothesis] (Accessed 8 November 2023). (2023) The Rare Earth Hypothesis: Assessing the Scarcity of Complex Life in the Universe. Available at New Space Economy: [https://www.newspaceeconomy.com/the-rare-earth-hypothesis-assessingthe-scarcity-of-complex-life-in-the-universe] (Accessed 10 November 2023). (2023) When did dinosaurs become extinct? Available at U.S. Geological Survey: [https://www.usgs.gov/when-did-dinosaurs-become-extinct] (Accessed 13 November 2023).
8
THE B-WORD
The Curse of Evolution and Lineage - Cost-Benefit Analysis By Bethany Megan Jones When Charles Darwin first published his theory of evolution in “On the Origin of species” in 1859, 7 it was widely regarded as bilge, yet now evolution is one of the most accepted and researched scientific theories. This is in part due to the work of scientists like Darwin but arguably the largest reason for this shift is the accumulation of irrefutable evidence that science has worked to provide over the last 150 years. Lineage has left organisms with a swathe of painful experiences and burdens to endure, some of which can be easily traced back to their source, others far more mysterious and obscure. Evolution often leads to characteristics that are of no benefit to an organism. In some cases, a species’ lineage may cause disadvantageous traits passed down from their ancestors that, whilst when first evolved were useful, now cause more harm than good to the species. Other traits seem to be as useless and painful now as they have always been since they first appeared. This is the curse of evolution. As no organism is completely new and unchanged from when it first appeared, every species has its own past of adaptations that build upon each other, evolving in and out of use. These ‘flaws’ seem to occur more in species that have evolved from a long line of ancestors and undergone many environmental changes and challenges throughout their evolution. Furthermore, they seem to appear more in newer species. For example, there are many of these characteristics found in humans and if the above conditions are to be believed, that may be due to their long lineage since the mammal class first evolved around 225 million years ago8. Humans are also
a relatively ‘young’ species, only having evolved in the last 200,000 years9 ,which when compared to ancient species such as sharks that were thought 10to first appear around 380 million years ago, makes humans practically infants. Similarly, the spotted hyena first appeared around 10 million years ago11, whilst considerably older than humans, they are by no means ancient.
7 (1859) Darwin Published ‘On the Origin of Species,
10 Davis, Josh. "National History Museum" [website].
Proposing Continual Evolution of Species.’ Available at: [https://www.genome.gov/Darwin-Published-On-theOrigin-of-Species] 8 Michael J Novacek, ‘Mammalian Evolution: An Early Record Bristling with Evidence’ (1997) 7 Current Biology. 9 "Your Genome Topics" [web document]. 2021. https://www.yourgenome.org/stories/evolution-of-modernhumans/ (Accessed 7th December 2023).
https://www.nhm.ac.uk/discover/shark-evolution-a-450million-year-timeline.html (Accessed 7th December 2023). 11 "Wikipedia (spotted hyena)" [web document]. 2023. https://en.wikipedia.org/wiki/Spotted_hyena (Accessed 7th December 2023). 12 "Hawai’i Pacific health" [web document]. 2019. https://www.hawaiipacifichealth.org/healthier-hawaii/behealthy/what-does-the-appendix-do-other-questions-aboutthe-bodys-mystery-organ/ (Accessed 6th December 2023).
There are many examples of all sorts of organisms that present vestigiality (useless organs/characteristics), and the reasons for these traits can usually be explained by looking at an organism’s lineage. However, in some cases, organisms appear to present characteristics and behaviours that have no reason and cause more issues than success with no apparent evolutionary value at any point at all or one that hasn’t been relevant for millions of years. Why do organisms not evolve out of these traits and why did they evolve them in the first place? There are in some cases no current explanation for those questions, but there are some interesting examples of these various situations caused by ancestry and evolution. For humans, there are many examples of when our past has left us with vestigiality. The most renowned example of which is the appendix, a vestigial organ it is of very little use to us. Though some scientists suggest it may be a holding area for certain gut bacteria that can hide there during antibiotic use and repopulate the gut after, it is an unproven theory.12 The majority of scientists agree that the appendix was of great use to our herbivorous ancestors who used it to
9
THE B-WORD break down tough tree bark and cellulose13in their plant-based diet14. Whilst many scientists argue the function of the appendix is misunderstood and may be of importance, what they cannot argue is that those who have appendectomies due to appendicitis seem to live a perfectly healthy life and have no long-term effects.15 Appendicitis discharges constitute 11.8% of all gastrointestinal hospital discharges,16 thus proving that the appendix, as of the moment, appears to have more of a negative effect on human life than a positive one.
two main demands humans have of their pelvises conflict, the need for a larger birth canal for our large-brained offspring and the ability to walk upright on two legs with agility and relative speed. Thus, we had to evolve a compromise, a pelvis wide enough to allow for larger brains in our offspring and yet narrow enough to provide a suitable balance for our two-legged lifestyle.
An example of pain caused by our ancestry that can be easily traced and is of use to us is our pelvis. Our pelvis is different to that of our ape relatives in a few keyways: they are shorter and wider which allowed humans to evolve to walk on two legs without the support of knuckles as needed for other primates. These changes also caused a widening of the birth canal17. Despite this widening of the birth canal, childbirth in humans is far more painful and arduous than in apes. This is because we bear young with highly developed brains causing the relative size of the foetal head and birth canal to be so similar that one in one thousand mothers have a child whose head is too large to birth naturally, thus requiring a caesarean section18- an option that has not been safely available for the majority of human history. The obstetrical dilemma states that the
Another example of humans being affected by their ancestry is the number of types of cone cells in our eyes; however, unlike the aforementioned evolution of the pelvis, this characteristic is of no apparent use to us and is simply passed down from our mammalian ancestors. At some point, around 250 million years ago our ancestors became nocturnal and did not return to the daylight until the extinction of the dinosaurs 66 million years ago19. In this time, the early mammals (belonging to a group called therapsids) gave some of their cone cells up in exchange for more rod cells. This led to humans having three types of cone cells20 and most other mammals only having two. Having a wider range of cone cell types in an eye allows for a broader spectrum of colour to be observed: reptiles have four types21 and birds have five22. As evident in our lineage, having more rod cells (which are useful to see in dark conditions) allowed early mammals success as nocturnal predators. However, it has left their descendants that are
13 Rhodes, Leonaura. "What are vestigial organs? 7 body
18 Lee-Shipman, Pat. "American Scientist" [website].
parts we don’t need." University Health News [web blog]. July 2019 https://universityhealthnews.com/daily/agingindependence/vestigial-organs-7-body-parts-we-dont-need/ (Accessed 6th December 2023). 14 Cheriyedath, Susha. "News Medical Life Sciences" [website]. https://www.news-medical.net/health/Why-doHumans-have-an-Appendix.aspx (Accessed 6th December 2023). 15 "NHS Website" [website]. https://www.nhs.uk/conditions/appendicitis/treatment/ (Accessed 6th December 2023). 16 O Soreide, ‘Appendicitis--a Study of Incidence, Death Rates and Consumption of Hospital Resources.’ (1984) 60 Postgraduate Medical Journal 341. 17 Siliezar, Juan. "What makes us human? It’s all in the hips." The Harvard Gazette [web blog]. 28th September 2022.https://news.harvard.edu/gazette/story/2022/09/geneti c-study-shows-evolution-of-human-pelvis/ (Accessed 6th December 2023).
https://www.americanscientist.org/article/why-is-humanchildbirth-so-painful (Accessed 6th December 2023). 19 University of Chicago Press Journals. "Did early mammals turn to night life to protect their sperm?" ScienceDaily. 15 October 2019. www.sciencedaily.com/releases/2019/10/191015131505.ht m (Accessed 7th December 2023). 20 Hicklin, Tianna. "National Institutes of Health" [website]. 2016. https://www.nih.gov/news-events/nihresearch-matters/new-color-vision-pathway-unveiled (Accessed 6th December 2023). 21 Healey, Mariah. "Reptile vision: what you need to know and how it pertains to your husbandry". For the Bio Dude blog [web blog]. 5th October 2020. https://www.thebiodude.com/blogs/helpful-husbandryfaqs/reptile-vision-what-you-need-to-know-and-how-itpertains-to-your-husbandry (Accessed 6th December). 22Yoseph A Kram, Stephanie Mantey and Joseph C Corbo, ‘Avian Cone Photoreceptors Tile the Retina as Five Independent, Self-Organizing Mosaics’ (2010) 5 PLoS ONE.
10
THE B-WORD now diurnal as being able to see less colours than other classes of animal. This is a good example of when evolution by its very nature has left an organism with a trait that is not necessarily actively damaging but does leave us with a less vibrant world than other animals. If early humans had had similar vision to a bird, it may have been easier to spot prey and hunt. Kestrels UV cone cells allow them to track voles from the sky as the UV reflecting off the urine trail allows for precise tracking of the animal from great distances.23 Thus, whilst there is no evidence or research to suggest that we are at a disadvantage due to our reduced number of cone cells it is a plausible speculation that having more would do us no harm and if not improve our vision may certainly allow us to see nature in a more vibrant way. An example of a mammal with a characteristic that has evolved with no apparent function and causes a great deal of pain is the Spotted hyenas’ pseudo-penis. The spotted hyena has one of the most traumatic and disturbing births in the animal kingdom: females give birth through a tube only an inch in diameter that is found in their clitoris. Their clitoris is shaped like a penis and referred to as a pseudo-penis and is caused by high levels of testosterone to allow for sexual mimicry. It is of great advantage to look like a male if you are a hyena, particularly if you are of low rank in the pack. Hyenas live in matriarchal packs where the dominate females feed first and will often kill or exile other low-ranking females. Additionally, the higher levels of testosterone compared to the male of their species allows for female dominance, increased aggression and muscle mass24. Despite this myriad of rewards received for the high levels of testosterone
present, they do not explain why the pseudopenis is used to give birth, only why it is present. Oddly, other hyena species also display sexual mimicry and yet none except the spotted hyena give birth through their male-like genitalia.25There does not seem to be an advantage to this gruesome birth. In fact it is such a poor way to give birth due to the small diameter of the clitoris that 2/3 of cubs suffocate during birth and 9-18% of mothers die giving birth for the first time.26 With all of this evidence to suggest why having a pseudo-penis, let alone giving birth through one is not particularly useful and in the case of the latter actually detrimental27, we don’t actually know why evolution allocated female spotted hyenas with such an odd and painful trait. There seems to be no links to their heritage or previous uses unlike human’s pelvises and the benefits of high levels of testosterone could all be achieved without the enlarged clitoris being used as a birth canal. Overall, evolution is cause of life’s rise and subsequent success on Earth. That does not however mean it is perfect, as examples show, the nature of evolution and all animals being descended from common ancestors leads to the possibility of useless or detrimental traits being passed down. Furthermore, sometimes evolution leads to characteristics in an organism that cannot be traced and seem to have no advantage. There is a lot about evolution that is still unknown or possibly misunderstood, and perhaps in the future, mysteries such as the spotted hyenas’ pseudo-penis will be explained. However, as of the moment, these mysteries are still the be explored and continue to marvel and confuse scientists all around the world. Much of evolution is a cost-benefit analysis between pain
23 Birkhead, Tim. "Audubon" [website]. 2013. Audubon
25 Head of Primates, George. "The wonders of animal
Society. https://www.audubon.org/magazine/may-june2013/what-makes-bird-vision-so-cool (Accessed 6th December). 24 Roberts, Stephen A., et al. "Effects of Testosterone on Muscle Strength, Physical Function, Body Composition, and Quality of Life in Intermediate-Frail and Frail Elderly Men: A Randomized, Double-Blind, Placebo-Controlled Study." The Journal of Endocrinology and Metabolism Volume 95, Issue 2, 1 February 2010, Pages 639–650.
birth" Wingham Wildlife Park [web blog]. 2nd June 2022. https://winghamwildlifepark.co.uk/the-wonders-of-animalbirth/ (Accessed 6th December 2023). 26Genomia. [web document]. https://www.genomia.cz/en/test/hyena/ (Accessed 6th December 2023). 27 Fawcett, Kirstin. "Mental Floss" [website]. 2017. https://www.mentalfloss.com/article/506378/why-dofemale-spotted-hyenas-give-birth-through-their-pseudopenises (Accessed 6th December 2023).
11
THE B-WORD and furthering the success of a species as evident in humans. Without these adaptations species would be stagnant, stunted, never changing. It is unlikely an organism will ever be perfect, and evolution is the only way for imperfect beings to adapt to their ever-changing worlds and continue to reproduce and survive. This sometimes works out well, other times it leaves their descendants left with odd and useless traits, but evolution in itself is an imperfect system. Charles Darwin
would most likely be very proud of how much closer his theory has taken science to understanding the miracle of life’s emergence, but we are nowhere near the finish line of fully understanding how living organisms came to be how they are today or why they are how they are. Evolution will most likely continue to both curse and bless all organisms until life on our planet ends.
12
THE B-WORD Bibliography 7. Birkhead, Tim. "Audubon" [website]. 2013. Audubon Society. https://www.audubon.org/magazine/may-june-2013/what-makes-bird-vision-so-cool (Accessed 6th December). 8. Cheriyedath, Susha. "News Medical Life Sciences" [website]. https://www.newsmedical.net/health/Why-do-Humans-have-an-Appendix.aspx (Accessed 6th December 2023). 9. Davis, Josh. "National History Museum" [website]. https://www.nhm.ac.uk/discover/sharkevolution-a-450-million-year-timeline.html (Accessed 7th December 2023). 10. Fawcett, Kirstin. "Mental Floss" [website]. 2017. https://www.mentalfloss.com/article/506378/whydo-female-spotted-hyenas-give-birth-through-their-pseudo-penises (Accessed 6th December 2023). 11. Genomia. [web document]. https://www.genomia.cz/en/test/hyena/ (Accessed 6th December 2023). 12. "Hawai’i Pacific health" [web document]. 2019. https://www.hawaiipacifichealth.org/healthierhawaii/be-healthy/what-does-the-appendix-do-other-questions-about-the-bodys-mystery-organ/ (Accessed 6th December 2023). 13. Head of Primates, George. "The wonders of animal birth" Wingham Wildlife Park [web blog]. 2nd June 2022. https://winghamwildlifepark.co.uk/the-wonders-of-animal-birth/ (Accessed 6th December 2023). 14. Healey, Mariah. "Reptile vision: what you need to know and how it pertains to your husbandry". For the Bio Dude blog [web blog]. 5th October 2020. https://www.thebiodude.com/blogs/helpfulhusbandry-faqs/reptile-vision-what-you-need-to-know-and-how-it-pertains-to-your-husbandry (Accessed 6th December). 15. Hicklin, Tianna. "National Institutes of Health" [website]. 2016. https://www.nih.gov/newsevents/nih-research-matters/new-color-vision-pathway-unveiled (Accessed 6th December 2023). 16. Lee-Shipman, Pat. "American Scientist" [website]. https://www.americanscientist.org/article/why-ishuman-childbirth-so-painful (Accessed 6th December 2023). 17. "National Human Genome Research Institute" [web document]. 2013. https://www.genome.gov/25520157/online-education-kit-1859-darwin-published-on-the-origin-ofspecies-proposing-continual-evolution-of-species (Accessed 6th December 2023). 18. "National Library of Medicine" [website]. 1984. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2417863/ (Accessed 6th December 2023). 19. "National Library of Medicine" [website]. 2010. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2813877/. 20. "NHS Website" [website]. https://www.nhs.uk/conditions/appendicitis/treatment/ (Accessed 6th December 2023). 21. Novacek, Michael. "Mammalian evolution: an early record bristling with evidence." Current Biology section of Science Direct, Volume 7, Issue 8, 1 August 1997, Pages R489-R491. https://www.sciencedirect.com/science/article/abs/pii/S0960982205800482 (Accessed 7th December 2023). 22. Rhodes, Leonaura. "What are vestigial organs? 7 body parts we don’t need." University Health News [web blog]. 9th July 2019. https://universityhealthnews.com/daily/agingindependence/vestigial-organs-7-body-parts-we-dont-need/ (Accessed 6th December 2023). 23. Roberts, Stephen A., et al. "Effects of Testosterone on Muscle Strength, Physical Function, Body Composition, and Quality of Life in Intermediate-Frail and Frail Elderly Men: A Randomized, Double-Blind, Placebo-Controlled Study." The Journal of Endocrinology and Metabolism Volume 95, Issue 2, 1 February 2010, Pages 639–650. 24. Siliezar, Juan. "What makes us human? It’s all in the hips." The Harvard Gazette [web blog]. 28th September 2022. https://news.harvard.edu/gazette/story/2022/09/genetic-study-shows-evolution-ofhuman-pelvis/ (Accessed 6th December 2023). 25. University of Chicago Press Journals. "Did early mammals turn to night life to protect their sperm?" ScienceDaily. 15 October 2019. www.sciencedaily.com/releases/2019/10/191015131505.htm (Accessed 7th December 2023). 26. "Wikipedia (spotted hyena)" [web document]. 2023. https://en.wikipedia.org/wiki/Spotted_hyena (Accessed 7th December 2023). 27. "Your Genome Topics" [web document]. 2021. https://www.yourgenome.org/stories/evolution-ofmodern-humans/ (Accessed 7th December 2023).
13
THE B-WORD
The impact of pH on a named biological system Allan Christopher Austin The measure of pH is formally known as a quantitative measure of the acidity or basicity of aqueous and liquid solutions – in simple terms, a concentration of Hydrogen (H⁺) ranging from 0 (acidic) - 14 (alkaline). It is a term widely used within the insightful fields of chemistry and biology given its intrinsic role within biological systems and chemical reactions. An example of the aforementioned importance is the regulation of blood pH between 7.35 - 7.45 to maintain proper bodily functions such as those associated with enzyme-substrate complex-based reactions. Deviation from optimal ranges may result in denaturation of the tertiary structure within protein active sites. This denaturation can occur due to the disruption and breakage of crucial bonds, such as hydrogen bonds, disulphide bonds and hydrophobic interactions within the protein structure. These bonds are essential for maintaining the specific shape and stability of the tertiary structure. As a result, the denaturation of the tertiary structure can impair the protein's ability to function properly in its active site. This is evident in Figure 1:
pH plays an incredibly intricate role with respect to cancer and its development within the body. This is especially evident when one takes a deeper look into the microenvironment of cancer cells. The typical pH of a cancer cell was found to range from 6.0 - 7.0, a noticeable difference given the narrow bounds governing optimal functioning of cells. This boost in acidity can be
28 Angela M Duffy, David J Bouchier-Hayes and Judith H
Harmey, ‘Vascular Endothelial Growth Factor (VEGF) and Its Role in Non-Endothelial Cells: Autocrine
mostly attributed to the increased production of lactic acid by cancerous cells via a metabolic process known as glycolysis. An acidic pH promotes the proliferation of cancer cells by facilitating the release of growth factors such as vascular endothelial growth factor (VEGF)- an extracellular signalling molecule. This factor stimulates the formation of new blood vessels by increasing migration and mitosis of endothelial cells upon activation by VEGF. Ultimately, constructing a network of blood vessels able to provide nutrients such as glucose or amino acids such as glutamine and oxygen towards tumour cells to sustain rapid growth28. This can be seen in Figure 2:
Additionally, another growth factor introduced by an acidic pH is transforming growth factor beta (TGF-β). TGF-β is a multifunctional cytokine that regulates cell growth, differentiation and apoptosis. It holds a complex role within cancer progression as it can act as both significant promoter and regulator. TGF-β can stimulate endothelial cell migration towards the tumour site, resulting in the formation of new blood vessels which further ensures continued growth and expansion of tumour cells by proliferation. 29
Signalling by VEGF’ (Nih.gov2013) <https://www.ncbi.nlm.nih.gov/books/NBK6482/>. 29 Joan Massagué, ‘TGFbeta in Cancer’ (2008) 134 Cell 215.
14
THE B-WORD
Application of nanotechnology to treat biofilm infections By Ester Hattingh This article is going to be focusing on 3 main applications of nanomaterials in the treatment of biofilms: nanomaterials with an intrinsic biofilm eradicating effect; nanomaterials as delivery vehicles for eradicating agents and environmentally responsive nanomaterials causing biofilm dispersion1. 1. What are bacterial biofilms? Biofilms are accumulations of microbe populations that are held together and adhere to surfaces by an extracellular polymeric substance (EPS). In human biofilm infections, bacteria are the most abundant in the microbe population. The bacterial arrangement in a biofilm is the most common lifestyle due to increased resistance to environmental stresses so improved chance of survival when compared to a planktonic existence, meaning bacteria exist as independent, single-celled organisms. Biofilm infections commonly form on medical implantation devices. This poster is going to focus on the treatment of established bacterial biofilms, to retain implant condition and reduce the need for device replacement (avoiding high risk of reinfection). The main examples of medical devices that are at risk of a bacterial biofilm infection are joint prosthesis, central venous catheters, endotracheal tubes, and mechanical heart valves where implant retention is crucial2. Figure 1 Scanning electron image of a Staphylococcus biofilm on the inner surface of a needleless connector. Photograph by Janice Carr, Centers for Disease Control and Prevention, Atlanta, GA USA.3 1H.M. Tran et al., "Nanomaterials for Treating Bacterial
Biofilms on Implantable Medical Devices," Nanomaterials 10, no. 11 (2020): 2253. 2 T.J. Webster et al., "Short communication: carboxylate functionalized superparamagnetic iron oxide nanoparticles (SPION) for the reduction of S. aureus growth post biofilm
2. Why is nanotechnology necessary? The main obstacle when treating biofilm infections is the EPS that surrounds the bacteria in a complex matrix. The EPS is made up mostly of polysaccharides as well as proteins, extracellular DNA and water4. This creates a barrier to the outside environment preventing conventional courses of antibiotics from working. Nanoparticles attempt to either diffuse through the EPS or cause catabolic reactions due to electrostatic surface interactions and nanoparticles’ multivalent properties. 3. Is there evidence for nanoparticles with intrinsic biofilm eradicating properties? Metallic nanoparticles are especially effective at targeting the EPS as some release soluble ions which experience a charge interaction with surface functional group of EPS and bacteria 1. An example of a nanomaterial with intrinsic biofilm destabilising properties is silver nanoparticles (AgNP) which when studied can be biosynthesised from P. zeylanica (plant extract). In this case the AgNP were tested on E.coli using the disk diffusion test; showing 96% to 99% bacteria death and up to 88% biofilm disruption 1. formation," International Journal of Nanomedicine (2013): 731. 3 R. Donlan, "Biofilms and Device-Associated Infections," Emerging Infectious Diseases 7, no. 2 (2001): 277–81, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2631701/. 4 H.C. Flemming, "EPS—Then and Now," Microorganisms 4, no. 4 (2016): 41.
15
THE B-WORD
4. How can nanoparticles act as vessels for antibiotic compounds? Nanocarriers (NC) can provide a solution to the challenges of reduced diffusion through EPS, drug degradation and poor interaction between drug and biofilm components1. Nanocarriers can closely control therapeutic dose as well as improve stability and release of stored pharmaceutical agent. These NC’s can be constructed with organic (lipid, polymer) or inorganic structures and can contain either antibiotics or non-drug agents1. An example of where the use of nanocarriers increased efficacy is shown is when a 2-day old S. paratyphi A biofilm was exposed to chitosan, as shown in
Non-drug agents carried by nanoparticles could include enzymes. For example, the enzyme deoxyribonuclease I (DNase I) destabilise the biofilm by targeting the eDNA of the ESP along with oxacillin (antibiotic from penicillin class)1. Both agents are stored in a positively charged chitosan nanoparticle which were shown to eradicate 70% and 100% of a mature S. aureus biofilm at an oxacillin concentration of 0.0625 and 2 µg/mL, after 24 h of treatment8. 5. How can environmentally responsive nanoparticles disrupt the biofilm?
Nanoparticles containing ciprofloxacin (antibiotic) and coated with Fucoidan5 (sulfated polysaccharide) there was a 1.6x increase in biofilm destruction. This is due to the NP dispersing the biofilm encouraging increased endocytosis (engulfing) of bacteria by phagocytes and releasing fucoidan which interacts with apoptosis molecules inducing cell death 6.
Even though some nanomaterials have intrinsically destructive properties, there is scope for external environmental changes to increase the extent of biofilm disruption. For example, magnetic field, light and pH influence the microenvironment of the biofilm causing the nanomaterial to transform or activate an agent within to become a more reactive species1. The activation of an infiltrated nanoparticle can be specific due to the specific engineered surface chemistry or non-specific due to mechanical heat or force.
Figure 2 Chitosan is a linear polysaccharide composed of randomly distributed β--linked D-glucosamine and N-acetyl-D-glucosamine extracted from shells of shrimp7. This molecule is used as both a transported agent and a structural component of the nanoparticle.
Firstly, magnetically responsive nanomaterials, a magnetic field is used to exert a force on the nanoparticles to facilitate penetration into biofilm2. For example, carboxylate functionalised superparamagnetic iron oxide nanoparticles (SPION) can be used in the treatment of antibiotic resistant (S. aureus). SPIONS are a type of metallic nanoparticle either in the form of maghemite, γ-Fe2O3 or magnetite, Fe3O4,2 which show magnetic properties in the presence of a magnetic field9. In this study the SPIONS were functionalised by amine, carboxylate, and isocyanate functional groups to
5 S. E et al., "Fucoidan coated ciprofloxacin loaded
7 Wikipedia, "Chitosan," 2019,
chitosan nanoparticles for the treatment of intracellular and biofilm infections of Salmonella," Colloids and Surfaces B: Biointerfaces 160 (2017): 40–7. 6 F. Atashrazm et al., "Fucoidan and Cancer: A Multifunctional Molecule with Anti-Tumor Potential," Marine Drugs 13, no. 4 (2015): 2327–46.
https://en.wikipedia.org/wiki/Chitosan 8 Y. Tan et al., "Enhancing antibiofilm activity with functional chitosan nanoparticles targeting biofilm cells and biofilm matrix," Carbohydrate Polymers 200 (2018): 35–42. 9 "Superparamagnetic Iron Oxide Nanoparticle - an overview," ScienceDirect Topics, accessed June 15, 2023.
16
THE B-WORD improve biofilm surface disruption as well as diffusion. They are described as superparamagnetic because of their ability to randomly flip direction of magnetism under the influence of temperature. The NPs are in a superparamagnetic state, meaning time between flips is so long that net magnetism is zero, when no magnetic field is present10 this property is partially responsible for the protection of healthy tissues around the biofilm. Amine, carboxylate, and isocyanate functionalised iron oxide nanoparticles disrupted 28.1%, 33.5%, and 31.1% of 24 h old S. aureus biofilm after 24 h of treatment, respectively, higher than 1 superparamagnetic IONs alone . Secondly, the introduction of exogenous H2O2 and changing local pH can induce the nanomaterial to catalyse oxidative species. The NP catalyses H2O2 into free radicals by the Fenton reaction, which is the enhanced oxidative potential of H2O2, when iron (Fe) is used as a catalyst under acidic conditions11. In the presence of the peroxide-like ion formed, 98% of E. coli biofilm was shown to be destroyed1. Another example of pH activated nanomaterials is when formed from diblock copolymers they assemble into cationic nanoparticles which show high affinities to negatively charged biofilm parts due to strong electrostatic interactions via multivalent tertiary amines on the nanomaterial polymer12. Thirdly, the use of photosensitisers in photodynamic therapy where heat and light induce a transformation and degradation of nanoparticle to release its contents. One technique, as shown in Figure 2, is vapour nanobubbles, induced by a laser, causing rapid water evaporation so that gaps can form between bacteria in the biofilm allowing antibiotic penetration.
10
"Superparamagnetism," 2020, https://en.wikipedia.org/wiki/Superparamagnetism, accessed June 15, 2023. 11 "Fenton Reaction - an overview," ScienceDirect Topics, accessed June 15, 2023.
Figure 3 Compare the difference between normal diffusion which is slow due to large aggregates of bacteria and laser induced nanobubble diffusion1.
Metal-organic-framework nanodots can use pH differences in the biofilm vs healthy tissue, when containing manganese dioxide and porphyrin, to induce oxygen singlet formation. Porphyrin in the nanodot acts as a photosensitiser as it absorbs light so that when the nanodot is exposed to near infrared light, MnO2 will cause increase the O2 production via H2O2 catalysation leading to biofilm surface parts decomposition. The metalorganic-framework containing porphyrin will continue to oxidise the O2 to from reactive oxygen species such as singlet oxygen, OHradicals, O2- radicals will eradicate the exposed biofilm.
6. Is there potential for other areas of research in treatment of bacterial biofilms? Yes, one example involving the use of quorum sensing as a chemical signalling and
12
B. Horev et al., "pH-Activated Nanoparticles for Controlled Topical Delivery of Farnesol to Disrupt Oral Biofilm Virulence," ACS Nano 9, no. 3 (2015): 2390–404.
17
THE B-WORD communication method in order to maintain the biofilm cycle: attachment, colonisation, development, maturity, and active dispersion; where dispersion occurs when conditions are no longer optimal for the specific adaptations of a
biofilm13. There is opportunity to interrupt this mechanism and induce dispersion of biofilm, additional antibiotics will address the problem of reattachment.
13 P. Cai et al., "Soil biofilms: microbial interactions,
characterization," Soil Ecology Letters 1, no. 3-4 (2019): 85–93.
challenges, and advanced techniques for ex-situ
18
THE B-WORD
Interesting Fact Beth Molyneux, former B-Word Journal Editor
A bacterium called Thiomargarita magnifica has been named the world's largest bacterium. It's an interesting organism due to how it stores it's DNA and it's immense size. 43
43 Natali Anderson, ‘Newly-Discovered Species of Bacterium Is Visible to Naked Eye | Sci.News’ (Sci.News: Breaking
Science News24 June 2022) <https://www.sci.news/biology/thiomargarita-magnifica-10936.html> accessed 17 December 2023.
19