Why my mind has been obsessed with apples? Well, I don’t know if it’s because I’m not suited to the office environment and my mind is just wondering about the most peculiar of topics. I first started thinking of apples a few weeks ago, when my girlfriend was upset and confused, as every time she ate an apple, her throat would itch. I remember thinking that’s weird, but not giving it too much thought. But then quite a few people in the offices had the same complaint. I thought maybe there may be a strange batch of apples from Tesco or Aldi, that had some type of dust or chemical allergen on them which was in turn causing a minor reaction. No big deal right a few people bought some apples havent been washed properly or have been on the shelf gathering dust for a few days longer than normal. However, yesterday I saw on Dr Rae’s blog (https://phasmarhabditis.wordpress.com) that him and a friend of his had the same issue from the apples in their garden. So there goes my idea that a farmer, or store had a harvest or stock of dodgy apples.
So because I’m relatively sad, and I am literally sat at a desk waiting for the phone to ring, which granted, when it does it can have its entertaining and humorous moments, I thought I’d see if there was any valid scientific reason for these itchy apples.
Alas, it wasn’t long before I stumble across a plethora of questionable health and nutrition sites which branded apples evil and dangerous. However wading through the hysteria of these health sites I did find some valid sources of information which didn’t advice abstinence from all things Malus.
I started off looking on the NHS website, which talked about oral allergy syndrome (OAS). Basically, the site said that OAS is an unusual immune reaction to proteins found on a specific food. I know it sounds scary when the words food and allergy are in the same sentence. But in the case of OAS, it is usually a mild immune response that causes a dry itch in the throat, and on rare occasion it may cause swelling in the lips and even tongue.
Apparently it’s not just apples that are said to be ‘evil’; peaches, kiwis almonds and hazelnuts are all common causes of OAS. Basically OAS is caused by allergy antibodies mistaking certain proteins in fresh fruits, nuts or vegetables for pollen which is why it can also be referred to as pollen food syndrome (PFS).
Its thought that the immunological reaction is caused by pollen. OAS is a common allergy for people who suffer from seasonal allergies, particularly people who suffer from reactions to birch pollen and grasses. It turns out, that the protein structure of the pollen from many trees, grasses and weeds is similar to that of the essential defence and growth proteins in many fruits, nuts, veg and even spices. The protein structure is in fact so similar, that they are recognised by our immune system as pollen, which in a hay fever sufferer, can trigger an immune response. Cool right?
So now on to the science part, pathogenesis related proteins (PR) are proteins that involved in plant defences. The gene sequences which code for these proteins are highly conserved in most species. PR proteins are produced in plant species when under pathogenic attack. These proteins are induced as part of a systematic acquired resistance, when a plant gets an infection the genes are activated and PR proteins are produced. Some of the PR proteins can have antimicrobial properties, they function by attacking cell surface membranes and vital cell organelles in bacterium or fungi.
Recent studies have shown that PR proteins are a rich source of allergens, additionally PR proteins are not regarded as superfamily of proteins. They are a collection of unrelated protein families which collaboratively function as the plants defence system. To date there PR proteins have been classified into 14 families. Interestingly, the plant food allergens associated with causing the unusual immune response are homologues to proteins that are members of the PR protein family.
I know it’s not strictly zoological, but I found it interesting, well more interesting that sitting waiting between very few clearing calls.