Physiology Archives - The Sciku Project

May 4, 2023July 10, 2024

Redundant Ergot by Sarah Das Gupta

The equine ergot
is mysterious and odd
someone blundered
by Sarah Das Gupta

Having had many horses in a long life, I can’t see the importance of the ‘ergot’ in 2023. For those unaware, the ergot is a small callosity on the underside of the fetlock of a horse. In horses, ergots can range from pea-sized to 3.8 cm in diameter and can be found on all four legs or absent on some or all of them.

The ergot has long been felt to be a vestige of the multi-toed foot of ancestral horses, and some horse owners trim them down to near skin level. However, the ergot’s redundancy may only be skin deep, as recent research suggests that the internal structure of the ergot beneath the visible external callus continues to have a function in modern horses.

Lusi and Davies (2017) studied the subcutaneous ergot tissue and found that “its overall connectivity, and the presence of nerve fibers and Ruffini endings strongly suggest that the ergot and its derived ligaments contribute to joint support, movement, and tension distribution in the distal limb.”

Further reading:

‘The Observer’s Book of Horses and Ponies’, R S Summerhays, Frederick Warne & Co. Ltd.

‘The Connectivity and Histological Structure of the Equine Ergot—A Preliminary Study’, Carla M. Lusi and Helen M.S. Davies, 2017, https://doi.org/10.1016/j.jevs.2017.01.003

Author bio:

Sarah Das Gupta is a young 81 year old. Loves writing haiku and most forms of poetry. Is learning to walk after an accident. Main outside interests include equine sports. Lives near Cambridge, UK. Read other sciku by Sarah here.

April 26, 2023June 1, 2023

Hibernation by Joy Stahl

Survival in space
Cold sleep on long missions
Arctic Ground Squirrel
by Joy Stahl

I’m a huge fan of science fiction novels and shows that use hibernation chambers to allow humans to reach distant planets in their lifetime.

I read an article about scientists who are studying arctic squirrels and how they hibernate, to create hibernation solutions for astronauts. Arctic squirrels are super-hibernators . They hibernate over winter for 7 to 9 months, reducing their core body temperature from 37 °C (99 °F) to as low as −2.9 °C (26.8 °F), and yet they manage to retain muscle and bone mass during this extended hibernation. Understanding this remarkable adaptation may help researchers looking at prolonged space travel and may also lead to improved critical and emergency health care and treatments.

Further reading:

‘Arctic squirrels may hold key to helping astronauts survive on long missions’, AccuWeather.com: https://www.accuweather.com/en/space-news/arctic-squirrels-may-help-astronauts-survive-long-missions/1481578

Author bio:

Joy Stahl is a middle school teacher in southwestern Kansas. Her poetry has appeared in Voices of Kansas. Check out Joy’s other sciku ‘1827-2023’!

June 18, 2021June 18, 2021

Indirect Inequality

Covid cares not for
the racial disparity
of heart disease

It was well-known before the pandemic that different racial/ethnic populations in the United States had different burdens of cardiovascular disease, with Black populations the worst affected.

The Covid-19 pandemic, however, has found ways of making bad things even worse, with deaths from heart disease and cerebrovascular disease rising across the whole of the USA. Yet new research by Wadhra et al. (2021) suggests that these increases aren’t evenly distributed across all racial/ethnic populations. Black, Asian and Hispanic populations have experienced a much larger relative increase in deaths (~19%) than the non-Hispanic White population (~2%).

A number of factors could be combining to result in this disproportionate impact of the pandemic on different racial/ethnic groups, including “reduced access to healthcare services, increased health system strain, and hospital avoidance due to fear of contracting the virus in high-burden areas. In addition, inequities in the social determinants of health that are associated with cardiovascular risk, such as poverty and stress, have likely worsened for these groups.”

Whilst depressingly unsurprising, these results make it clear that the United States urgently needs public health and policy strategies to “monitor and mitigate the short- and long-term adverse effects of the pandemic on the cardiovascular health of diverse populations.”

Original research: https://doi.org/10.1161/CIRCULATIONAHA.121.054378

July 17, 2018July 17, 2018

Eggy difference

The Baltic flounder:

Native to namesake region.

Eggy difference.

A new species of flounder has been identified as separate from the European flounder by Momigliano et al (2018). The Baltic flounder (Platichthys solemdali sp.) is native only to the Baltic Sea – the first fish species to be identified as endemic to the area.

Its reproductive behaviour differs from the European flounder, spawning eggs that sink in coastal areas as opposed to buoyant eggs in open water. There are also differences between the species in egg morphology, egg and sperm physiology. Unfortunately, the small morphological differences mean that it is difficult to unambiguously distinguish the species and genetic methods or egg/sperm analyses are required.

Original research: http://dx.doi.org/10.3389/fmars.2018.00225

April 17, 2018May 20, 2021

Have frog, will travel

Have frog, will travel,

yet what impact on welfare?

Best to avoid moss.

Transporting animals for research, agricultural, conservation or leisure reasons can involve a range of potential stressors. It’s therefore important to be aware of the impact of transportation on animals so as to minimise any negative effects.

African clawed frogs are a common laboratory animal, used for a range of developmental studies. Holmes et al (2018) investigated the impact of transportation between research facilities. They found that transportation and re-housing had a negative impact across a short- and longer-term, with corticosterone (a ‘stress hormone’) remaining high for 1 week and body mass remaining low for 5 weeks after transportation. Investigating further the researchers found evidence that being transported in moss might be the least preferable transport medium, with water or sponge appearing to be more suitable.

Original research: https://doi.org/10.1016/j.ygcen.2018.03.015

Interested in African clawed frogs? Check out these other Xenopus sciku: ‘Clawed frogs indicate‘, ‘Xenopus enrichment‘, ‘Fungal culprit‘ and ‘Reservoir or predator‘.

April 3, 2018April 30, 2018

Cup handled mice

Cup handled mice show

improved glucose tolerance

and less anxiousness.

When performing scientific research with animals, it’s important to ensure that the procedures used do not themselves impact upon the results obtained. Laboratory mouse handling method has already been shown to impact upon mouse anxiety in common behavioural tests. However it seems that handling can have physiological impacts too.

Ghosal et al (2015) compared the behavioural and physiological responses of laboratory mice to either tail handling or cupped handling techniques. Cupped handled mice showed fewer anxious behaviours in a common behavioural test, reduced blood glucose levels and a lower stress-induced plasma corticosterone concentration in response to an overnight fast compared to tail handled mice. The researchers also found that obese laboratory mice handled using the cupped method demonstrated improved glucose tolerance.

Replication and repeatability are crucial components of science and this paper is a perfect demonstration of this – the researchers are from different research laboratories and in a different country to the mouse handling work that preceded it. In this way not only does it build on what came before, it also strengthens those earlier findings. Yet the mouse handling story is not finished yet, click here for the next chapter of this tale/tail!

Original research: https://doi.org/10.1016/j.physbeh.2015.06.021

January 23, 2018January 23, 2018

Beak trimming distaste

Beak trimming distaste,

yet long beaks lead to poor health.

Best of a bad bunch?

Sometimes it’s better to cause harm for the right reasons rather than allowing worse harm to occur. Egg-laying barn hens typically have their beaks trimmed to reduce pecking damage but this practice results in pain and sensory loss for the birds. As a result the practice of beak trimming is being debated worldwide and some countries have already banned it based on welfare concerns.

Riber and Hinrichsen (2017) compared the welfare of trimmed and non-trimmed flocks of hens across 10 separate farms and across 62 weeks. They found that beak trimming actually resulted in higher conditions of hen plumage, skin and keel bones, as well as decreased mortality. Whilst beak trimming seems distasteful, this evidence suggests that it may be the best option after all.

Original research: https://doi.org/10.3389/fvets.2017.00222

January 19, 2018January 19, 2018

Increase carpet tog

Cold stress avoided

in laboratory mice –

increase carpet tog.

Temperature is an important element of animal care and it’s crucial to ensure that captive animals don’t overheat or suffer cold stress. Laboratory mice are often housed with a floor substrate of wood chips which may be useful in reducing cold stress.

Freymann et al (2017) found that the depth of this floor material influenced mouse physiology. Specifically a deeper wood chip layer resulted in mice with reduced adrenal, liver, kidney and heart weights and an increased tail length. These traits have previously been observed in mice housed under warmer conditions suggesting that the deeper substrate material is acting as an insulator and could be used to reduce cold stress in this captive species.

Original research: https://doi.org/10.1177/0023677217694400

September 25, 2017September 25, 2017

The climate matters

when measuring hormones from

faeces – be careful!

Measuring changes in hormones can tell us a lot about an animal’s welfare, health and reproductive condition, and non-invasive sampling (for example using faecal matter instead of blood) can limit the amount of stress caused to the animal being monitored. But faecal samples that are collected on an opportunistic basis might not be fresh or may have been exposed to the elements prior to collection. Does this matter?

Research by Yarnell & Walker (2017) suggests that temperature does indeed have an effect on the results obtained, with exposure to room temperature and high heat showing an increase in faecal glucocorticoid metabolite levels over time. This fundamental work shows the importance of considering sample collection and storage whilst designing experiments.

September 18, 2017September 18, 2017

Alchemist goldfish

change acid to alcohol

through doubled proteins.

Many species of carp (including goldfish) can survive for months over winter in frozen lakes despite a lack of oxygen. Without oxygen they use anaerobic respiration resulting in the production of lactic acid. To avoid a deadly build up of lactic acid the fish convert it into ethanol which diffuses across their gills into the surrounding water.

Researchers have now discovered how the fish do this. During energy production in the absence of oxygen a mutated set of proteins switches the metabolic pathway within mitochondria to produce ethanol instead. The fish have two sets of these proteins, one set which is very similar to that found in other species and one set that appears to be a duplicate of the first. These sets of proteins appear to have arisen during a whole genome duplication event approximately 8 million years ago and have enabled the fish to survive in conditions other species can’t. Fagernes et al, 2017.

July 21, 2017May 20, 2021

Clawed frogs indicate

by action and reaction

a choice between shades.

Ensuring the welfare of animals used for research is vital both from an ethical stand point and for the quality of the research produced – animals in poor condition do not produce accurate or reliable results. The African clawed frog is a common research species found in laboratories around the world but little work has investigated how to optimally house it in captivity.

Holmes et al (2016) found that a black tank background produced lower levels of ‘stress’ hormone (corticosterone), lower amounts of stereotypical behaviour and a smaller loss in body mass than a white tank background.

As African clawed frogs are naturally dark green/brown in colour and use camouflage to avoid predation, a light background might be more stressful for the frogs as they may appear more exposed. Providing dark tank backgrounds could therefore be an easy method for improving the welfare of thousands of African clawed frogs housed in captivity around the world.

Interested in African clawed frogs? Check out these other Xenopus sciku: ‘Fungal culprit‘, ‘Have frog, will travel‘, ‘Xenopus enrichment‘ and ‘Reservoir or predator‘.