24 minute read
Nota Bene: The Scottish Wild Mushroom Code Scottish Natural Heritage
The Scottish Wild Mushroom Code Scottish Natural Heritage Available at: www.nature.scot/plants-animals-andfungi/fungi
The countryside is a working landscape. Please be aware of your own safety and follow the Scottish Outdoor Access Code (https://www.outdooraccess-scotland.scot/). In accordance with this code, there are some instances e.g. commercial harvest, where you must make contact with the land manager before you collect mushrooms.
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By respecting the natural environment, you can help to manage and conserve the countryside. When collecting mushrooms for any purpose, please consider the following points:
What to collect Wildlife, especially insects, need mushrooms too, so only collect what you will use. Some mushrooms are poisonous and others rare and should not be collected— only collect what you know and take a field guide with you to identify mushrooms where you find them. Some species are vulnerable, so please consider whether there is an alternative species that is more common that might suit your purpose.
How to collect Allow mushrooms to release spores. Do not pick mushrooms until the cap has opened out and leave those that are past their best. The main part of the mushroom is below the surface. Take care not to damage or trample it, and do not disturb its surroundings. Scatter trimming discreetly in the same area that the mushrooms came from. Where to collect Before you collect mushrooms at a nature reserve, please always seek advice from the manager, as special conditions may apply. Visit www.snh.gov.uk to find out more about protected areas in Scotland.
If you own or manage land Mushrooms are a critical part of the natural cycle in grassland and woodlands; if these are compromised, all elements of the ecosystem will be affected. Be aware that your management activities may affect mushrooms.
If you wish to run a foray or collect for scientific purposes, remember to: Ensure the safety of your party; make contact with the land manager in advance of your visit. Give a record of what you have found to the land manager and explain the significance of your findings.
When we’re taught about the immune system at school, it is so often compared to a battlefield. Your white blood cells are the soldiers, defending against the bacteria or virus invaders. These concepts often resonate more with people when they are turned into black and white violence. But your body is far more complicated, and far more wonderful. It starts before you’re even born, as you grow in the warmth of the womb. You’re covered in a blanket of sorts, a layer of cells called epithelia, knit together with tight junctions that close the barriers to the outside world. There’s a continuous flow of air throughout the body— your own in-built ventilator, developed millennia before the first light bulb was switched on. Mucus coats the insides of these airways like a balm; a sticky secretion where inhaled droplets become trapped. Finger-like tendrils of cilia then sweep these away to be coughed up— into a nearby tissue ideally or, perhaps more realistically, the back of your elbow. But sometimes, things slip through. Substances entering from outside the body are marked as foreign with an antigen. These are the ‘non-self’ to the ‘self’ of your body’s tissues. The main principle of your immune system is to defend against ‘non-self’ without ‘self’ being a target of destruction. Protecting your boundaries without destroying yourself. There are two layers to the immune system; the innate, and the adaptive. Your rudimental but flawed generalised reaction, and the one that watches, waits, and then learns. All body cells play a part in the innate immune system. When a harmful microorganism with an antigen— a pathogen —begins to attack them, they produce chemicals to alert neighbouring cells. Distress signals, a cry for acknowledgement, of ‘I’m hurting, please help’. You have many types of white blood cell ready to respond. Natural killer cells are as brutal as their name, destroying any substance marked with an antigen, releasing toxins to induce cell selfdestruction. Forcing death by one’s own hand. How strange that we decided to name them this way, designating instant destruction as synonymous with nature. The only protection the body’s own cells have against this blanket brutality is a specific marker of protection, a talisman. Some viruses manage to hijack this and hide it, though, and so the natural killer cells can end up attacking their own. Another reason why this innate immune system cannot be relied upon long term— the adaptive response is soon needed. Phagocytes are also involved in the first response, peppered with purple pellets ready to dissolve unfamiliar substances. They recognise the pathogen and start ingesting immediately, consuming them inside out. They then present the remains of the digested pathogen as complexes on their surfaces. Again, some might
describe this as a soldier proudly displaying their spoils of war on their banners. But really, it’s more like a justification, evidence that there is a threat to explain this violence.
This phenomenon is known as MHC restriction, and it acts a safety mechanism to ensure your immune system isn’t being activated too easily. It is only when these complexes are presented that the next phase can kick in. This is because the innate immune system and inflammatory response can only hold off an infection for so long. Ultimately, a specific immune response needs to be activated: the adaptive immune system. B cells and T cells are the agents, the artists. We measure T cell count to check how well the system is ticking over. If the workers are down, it means it’s failing, and you have an autoimmune deficiency syndrome (AIDs). T helper cells bind to the complexes presented by the phagocytes, and this gesture of unity is the go-ahead for B cells to start producing antibodies. Antibodies are the tailor-made potions.
There are a potentially infinite number of antigens the immune system might encounter, and so it is crucial that the immune response is able to adapt and reflect a similar level of diversity. But it would be impossible to code every possible antibody required into our genes and still fit our DNA into such tiny spaces within cells. Instead, B cells can manipulate tiny regions of their structure in billions of ways, to mould themselves into the right fit for each antigen. This then allows them to personalise these antibodies, creating concoctions that destroy with intimate, intricate finesse. They neutralise the harmful toxins, stick to the surfaces of pathogens like flies, impairing their every action down to their ability to move. Then they poke the sleeping bear— the cytotoxic T cells. These are the most powerful cells of your immune system. When immature, T cells undergo a rigorous education in the thymus gland before they are released into the bloodstream. Many are quick to stylise this as a military camp, but it is far more akin to intense therapy, essential for cytotoxic T cells because of their destructive nature. They are tested with a variety of ‘self’ antigens, and any T cells that start trying to attack them undergo negative selection and are destroyed. This essential mechanism prevents the immune system from reacting to the body and is known as immunological self-tolerance. Your body must learn to accept itself before it is ready.
The role of cytotoxic T cells in the immune response is to form the most specific and potent method of death for the pathogens. They make contact with the microorganism cell wall, fitting so perfectly together with them that harm cannot seem possible. But it is this deadly harmony that allows them to bore holes into their walls; they are serial killers with drills. Following this
dismemberment, they release deadly toxins into the pathogen’s very insides, defragmenting their DNA, tearing apart every shred of their code. Judge, jury, executioner.
Some types of pathogens— viruses —hijack your own cellular machinery to grow and infect, and yet the cytotoxic T cell can still destroy them without harming the ‘self’ of your body’s cells. There is no chaos in this total annihilation. Meanwhile, the environment in the body has also changed. The chemicals released by the innate immune system cells trigger a series of changes that you already know like the back of your hand when it comes to illness. The flush in your face, the sweat on your brow, is a science. It’s your blood vessels widening, making easier roads for your defences to stream down to where they are needed. The fever that burns your skin is a necessary measure too, your body purging itself. You might catch yourself already reaching for metaphors to simplify this complex process. Keep the foreigners out? Doesn’t sound too unfamiliar, especially in today’s climate. But another key principle of your immune system is that it must accommodate for the presence of certain antigens. In some cases, an aggressive immune response simply serves no useful purpose— some pollen crossing into your lungs would hurt your body far more to attack than to tolerate. In other cases, the presence of foreigners is crucial. The bacterial flora in your gut outcompetes otherwise infective species from growing there. Chemicals such as lactate are produced by bacteria in the vagina, creating an acidic environment that protects against many potentially damaging organisms. Diversity is essential to survival. When your immune system goes into overdrive and starts to turn on those who are different, the whole body suffers, and becomes diseased. Really, the closest comparison between your immune system and an army is that both often attack the innocent. Sometimes this means you react when you should not. Allergies, for example, are hypersensitivity reactions. Others are born with genetical defects that mean your body has forgotten itself, the lines between ‘self’ and ‘non-self’ erased. These autoimmune conditions are the result of the code of your identity rewritten, the protective measures scribbled away at birth. All your immune system can see is that everyone is the enemy, including yourself. Defence turns into self-destruction. Most of the time though, your immune system isn’t anything like a collection of soldiers. It is a collection of memories. A memory T cell and B cell exists for every killer version. Watching, memorising the lessons learnt. The scholars in the watchtowers, keeping a record of the antigens, the antibodies, the cytotoxic cells used. This is immunity. When the same pathogen attacks again, the team reunites, faster, with less need for the theatrics, the crudity, instead reusing the tried and tested methods. It can move beyond the innate immune response to the adaptive much more quickly. Destruction, but with the refined precision of familiarity. Your body survives by believing in the inevitably of a next time.
Vegetal bebop Ramsey Affifi
In normal times, the genes peppered across a plant’s DNA function more or less according to the common metaphors of popular science. Here, they look very much like ‘instructions’ used to build the plant’s body and direct its behaviour. But when a plant encounters an unexpected circumstance, things get wild. The instruction metaphor breaks down, and a new insight into the interconnected nature of genes, organism and environment is revealed.
I will zoom in on one wild phenomenon here, to make the point. Forty years ago, cracks in the genes-are-instructions metaphor had already appeared with the discovery of ‘alternative splicing’ (Berget et al, 1977). Alternative splicing occurs when a gene gets transcribed differently than ‘usual’. One way to think about what this means is to imagine a gene to be a paragraph of text. Under normal circumstances, the gene is expressed by pulling specific words and sentences from the paragraph and putting them together to be read. But in certain conditions, some of those words or sentences might be omitted, or others put in. In language, this amounts to a change in meaning. In genetics, this means changed physiology and behaviour.
Gene transcripts are shuttled away to get translated into long stringy molecules called proteins. Different parts of proteins push and pull at each other, and the strings often fold into complex but very specific shapes that then specify how the protein interacts. A dizzying array of different protein shapes enable and participate in an equally dizzying array of functions. If alternatively spliced transcripts are translated, these proteins —known as protein isoforms— have a different shape than their regular counterparts, and so can interact differently. Some protein isoforms seem like well-established alternatives that can be pumped into action in the face of common disturbances, such as drought. But not all alternative proteins are evolutionarily conserved ‘Plan Bs’ waiting idly in the toolkit (Mastrangelo et al. 2012). For better or worse, it appears the number and nature of protein isoforms is not prescribed. A door is opened for the creative role that chaos plays in plant life. Some isoforms turn out to be nonfunctional. They are quickly degraded and their building blocks re-used. Others wreak havoc in the form of deformity and disease. Still others end up assisting the plant in new ways.
It turns out that alternative splicing in plant genes is especially prolific when a plant is encountering a novel stress. Why would a plant bother creating all these variants, with nonfunctional or unpredictable effects, at a time that requires urgent coordinated response? The answer turns out to be exquisitely Darwinian: in precarious times, it may be advantageous to produce a lot of new possible solutions to a danger. To do so, it adopts a randomization strategy. In risky times, it pays to take risks. Doing so, the plant increases the odds of an adaptive response. By generating variations of its gene products, the plant is increasing its repertoire, brainstorming without a brain.
This is roughly the same thing that happens in species at the population level in the process known as ‘natural selection’ (Darwin 1859): diversity in a population of organisms increases the likelihood that when given an environmental disturbance, at least some organisms of that species will survive long enough to pass on their genes. At the organism level, alternative splicing increases the chance that some behavioural response to a stress will be beneficial for the plant’s survival.
So, plant genes are more likely to produce predictable proteins when living conditions are stable, but the plant quickly generates creative chaos out of its genes when it needs to. With this insight, what happens to the ‘instruction’ metaphor? It seems to me this: the plant regulates and deregulates its genes, streamlining their effects in some contexts, relaxing those constraints in others. When genes behave in a streamlined way, it looks like they are deterministically instructing the plant cells. But alternative splicing during stressful conditions shows that if such determinism sometimes exists, it is only because the plant is determining it. The instructor is the organism, shifting how it uses its cellular resources in response to its shifting environment. In some situations it relies on routine, in others on creativity.
Alternative splicing is common in all eukaryotes, not just plants. But because plants cannot escape threats by running, slithering or flying away, the capacity to generate novel possible solutions seems especially crucial to the way they make a living. Readers of this journal will know that the ‘secondary metabolism’ of a plant is the set of processes whereby plants generate those complex chemical orchestras that so define their unique contributions to ecology as much as to economy. Consider the deluge of alkaloids, polyphenols, and terpenes that plants bring into the world: it is these chemicals that are used to ward off pests and attract allies, but that are also concentrated into tinctures and suffuse our aromatherapies. Notably, the secondary metabolism of plants seems highly susceptible to alternative splicing. For instance, 75% of Solanum lycopersicum (tomato) genes associated with producing secondary metabolites undergo alternative splicing (Clark et al. 2019).
In humans, there are more genes getting alternatively spliced —and spliced in more different ways— in the brain than anywhere else in the body (Yeo et al 2004). Just as animals employ alternative splicing to increase the problem-solving versatility of their neurons, plants use it to improvise volatile variations on their favoured fragrant themes.
Welcome to jazz ecology. References Berget S.M., Moore C., Sharp, P.A. (1977). ‘Spliced segments at the 5' terminus of adenovirus 2 late mRNA’. Proceedings of the National Academy of Sciences of the United States of America, 74(8), pp. 3171 –5. Clark, S., Yu, F., Gu, L., Min, X.J. (2019). ‘Expanding alternative splicing identification by integrating multiple sources of transcription data in tomato’. Frontiers in Plant Science 10, pp. 1 - 12. Darwin, C. (1859). On the origin of species. London: John Murray. Mastrangelo, A.M., Marone, D., Laidò, G., De Leonardis, A.M., and De Vita, P. (2012) ‘Alternative splicing: enhancing ability to cope with stress via transcriptome plasticity.’ Plant Science 185-186, pp. 40-49. Yeo, G., Holste, D., Kreiman, G. et al. (2004). ‘Variation in alternative splicing across human tissues.’ Genome Biology 5(10), pp.1 -15
Drawing the Magic from the Mushroom Dr. Audrey Cameron
Recent research confirms that mushrooms present an unlimited source of pharmaceutical compounds with unique and potent properties. Ganoderma is a genus of medicinal mushrooms which are usually non-edible, with coarse texture and therapeutic effects (Wasser 2005). Recently, Ganoderma lucidum has been recognised as one of the important medicinal mushrooms, consisting of highly bioactive secondary metabolites with an enormous variety of chemical structures (Gong et al, 2019). Nearly 700 different chemical compounds were discovered in this humble fungus!
So, what are metabolites? They are products of metabolism; chemical processes in the cells which produce energy. A secondary metabolite is not directly involved in those processes, but usually has an important ecological function. For example, fungi produce a huge variety of antibiotic secondary metabolites and pigmentary secondary metabolites, which give fungi their beautiful colours. These bioactive chemical molecules can be extracted from Ganoderma lucidum’s fruit body, mycelium, or spores. These molecules include a wide range of chemicals, mainly polysaccharides, steroids, terpenoids, phenols, nucleotides. Here are the general chemical formulae of these chemicals: Polysaccharides
Steroids
Terpenoids
Phenols
Nucleotides
Polysaccharides and triterpenoids are usually considered important compounds with beneficial properties in the treatment of a wide range diseases, but recent research has also recognised the importance of phenolic compounds (Yuen & Gohel, 2005; Ferreira et al., 2009).
The medicinal efficacy of all of these compounds depends hugely on the extraction and purification methods used (Gong et al., 2019). The extraction conditions need to be optimised to extract each specific compound and retain its desired bioactive effects. Research is being carried out to find the optimum conditions for extracting different compounds from Ganoderma lucidum.
The type of solvent has a significant influence on the extraction process, and the chemical composition of the extract. The solubility of different chemical compounds differs in different solvents. For example, methanol, ethanol, aqueous and a mixture of ethanol-water solvents are commonly used for extraction— but methanol is toxic, so is not suitable for extracts destined for human consumption.
Different extraction methods have been developed to improve the efficacy of extraction of different chemical compounds without affecting bioactivity. Here are some of the most common:
Organic solvent extraction: This is a common and traditional extraction method, but is quite timeconsuming and requires large amounts of organic solvents, such as methanol and ethanol. Nor is it the most efficient method, yielding quite low levels of the chemical compounds.
Ultrasound-assisted extraction: An alternative to organic solvent extraction, with lower extraction times, lower solvent consumption and higher yields of chemical compounds.
Microwave-assisted extraction: This is a very quick extraction method, taking less than 5 minutes. Supercritical fluid extraction: A new method, using the latest ‘green’ extraction solvent Supercritical carbon dioxide facilitates extraction at lower temperatures, which means the chemical compounds are less easily affected by the process. Thus, the bioactivity of the chemicals is preserved.
Fractional precipitation: Ion-exchange chromatography and ultrafiltration are commonly used for extracting polysaccharides.
There is an excellent chapter— ‘Chemistry of Components in Ganoderma’, by Gong, Yan, Jie Kang & Chen, 2019 —which lists the structural classifications and characteristics of each chemical compound found in Ganoderma, as well as the optimal separation methods for each chemical compound.
It has been fascinating to write this short article; learning about Ganoderma and its vast number of chemical components. Next time I see it in the woods, I will treat it with respect.
References Ferreira, I.C.F.R.; Barros, L. & Abreu, R.M.V. (2009) ‘Antioxidant in Wild Mushrooms’, in Current Medicinal Chemistry,16:1543–1560 Gong, T.; Yan, R.; Kang, J. & Chen, R. (2019) ‘Chemical Components of Ganoderma’, in Advances in Experimental Medicine and Biology, 1181:59-106 Wasser S. P. et al (2005) ‘Ganoderma lucidum’. In Coates P.M; Betz J.M; Blackman M.R; Grass G.M; Levine M; Moss J & White, J. (eds) Encyclopedia of Dietary Supplements. New York: Marcel Dekker: 603–622 Yuen, J.W. & Gohel, M.D. (2005) ‘Anticancer effects of Ganoderma lucidum: a review of scientific evidence’, in Nutrition and Cancer, 53:11 –17
In October…. Ruth Crighton-Ward
One of the main differences between Horticulture and Herbology is the classification of ‘weeds’. Prior to studying Herbology, I would never have entertained the notion of deliberately cultivating Chickweed (Stellaria media) or Dandelions (Taraxacum officinalis). Herbology does not consider plants as weeds and tends not to be interested in cultivars (cultivated varieties). Instead, Herbology favours plants in their original, most natural form. Many plants which have medicinal value carry a species name of officinalis or vulgaris, like Pot Marigold (Calendula officinalis) or Thyme (Thymus vulgaris).
The definition of a weed is just a plant growing where it is not wanted, so a stinging nettle (Urtica dioica) is often regarded as a nuisance. Its strong yellow roots can spread far, creating more nettles. In attempting to pull up one nettle, more nettles will be dislodged and pulled towards you. This usually results in any exposed area of skin coming into contact with their stinging hairs. Yet there is so much more to this plant than that familiar, painful sting. Medicinally, nettles have been used since ancient times. Tea made from the leaves is a gentle diuretic, helping to flush out kidneys and bladder, soothing urinary infections. As an edible plant it has a greater content of iron and other minerals than spinach does. Urtica dioica is also an effective soil indicator; its presence shows loam-based soil, rich in humus and the flowers are a good source of pollen and nectar for butterflies. A few handfuls of nettle leaves covered with water then left for a few weeks will create a plant feed rich in nitrogen, albeit somewhat smelly. A cupful of this liquid diluted in a watering can provides a great foliar feed for the development of healthy leaves.
Another ‘weed’ which serves a purpose, other than just to irritate gardeners, is Plantain. There are two types common to our gardens; Greater Plantain (Plantago major), and Ribwort (Plantago lanceolata). Both are used medicinally, although as a remedy for bites and stings the Greater Plantain is second to none and a valuable tool for the gardener. In one garden, I accidentally annoyed a bumblebee and, as a result, received an extremely painful sting. Whilst hopping around cursing, I recalled the Greater Plantain in the garden, grabbed a few leaves, chewed them for about ten seconds then applied the mush to the affected area. The relief was instantaneous, and the pain completely disappeared within seconds.
So, it’s sometimes good to leave a small patch of the garden uncultivated and see what ‘weeds’ appear and what they can be used for. You may be pleasantly surprised. The wildlife will also thank you for this. By October, summer has departed for another year. However, this month can bring some gentle weather. The leaves are changing colour, but
haven’t yet all fallen and this is the best time for foraging. As Keats observed two hundred years ago, this is the “Season of mists and mellow fruitfulness”. Autumn fruiting berries such as Bramble (Rubus fruticosa), Sloe (Prunus spinosa) and Hawthorn (Crataegus monogyna) are in plentiful supply, and there is an abundance of fungi.
Edible plants to be harvested in October include chives (Allium schoenprasum), apples (Malus domestica), carrots (Daucus carota), beetroot (Beta vulgaris), spinach (Spinacea oleracea), tomatoes (Solanum lycopersicum) and autumn raspberries (Rubus idaeus). The bulbs of wild garlic (Alium ursinum) can be harvested at this time of year. Although not widely regarded as a plant for domestic gardens, it can make a great addition to a woodland or more shady section in a garden.
Now is also a good time to scatter seeds for germination in the spring. Plants such as Lady’s Mantle (Alchemilla mollis) and Foxglove (Digitalis purpurea) will happily be grown this way.
October is a good time of year to divide plants. Growth has slowed or stopped in many herbaceous plants, yet the soil still retains a certain amount of heat and the frosts have not yet settled in. This moderate temperature minimises the shock plants will go through when divided. Division is a great method of propagation, creating a completely new plant. If a plant has grown too big, this is a good way of reducing its size for the following year. Divide using a sharp spade, swiftly slicing through the crown of the plant. Some plants are better divided by prising apart using two garden forks. The divided plants should be put back in the ground as soon as possible and given a good watering. The series of photos demonstrate the division of an Iris (Iris sibirica), from its initial to its finishing position. The plant is removed from the ground, divided by using two garden forks, then each plant is put into position and watered. Now we have two healthy plants. Buying an Iris of that size in a garden centre would probably set you back around £15, so division is a great way of saving money. Finally, if plants are needing to be dug up and moved elsewhere in the garden (transplanted) then this month is a good time to do that. There are really two good times of year for transplanting, spring and autumn. Spring just before the new growth kicks in and autumn just as the growing season comes to an end. Plants shouldn’t be divided or moved in the middle of summer or winter when the temperatures are more extreme.
You might also want to make a little time to order / purchase garlic bulbs ready for planting. Next month we’ll look at the planting process for this wonder bulb and catch up on the gardening jobs that can be done later in the autumn and throughout November.
In the meantime, enjoy whatever time you get in the garden.
Photos: Ruth Crighton-Ward
Anarchy in the Stock Beds Marianne Hughes, GPG volunteer
Since mid-March 2020, the Globe Physic Garden (GPG) volunteers have been unable to work in the Royal Botanic Gardens, Edinburgh. Since the RBGE opened to visitors in early July, we have watched with some interest— and increasing frustration— as a variety of herbs make their takeover bids. We knew the St John’s Wort (Hypericum perforatum) would self-seed everywhere, as we are always finding it in the Stock Beds and GPG in the best of times. Now the Mugwort (Artemisia vulgaris), Fennel (Foeniculum vulgare), Evening Primrose (Oenothera biennis), Chicory (Cichorium intybus) and Red Orach (Atriplex rosea) have joined the party. In the Stock Beds there is a similar free-forall, augmented by the Horseradish (Armoracia rusticana) and Sheep’s Sorrel (Rumex acetosella).
While the winter will see some dying down of many plants, come Spring 2021 the seeds of all these plants will germinate and make a spectacular come-back. Let’s hope we can return before they do! However, the glory of the Echinacea (E. purpurea)— surviving the frosts earlier this year— has been wonderful to behold.
