ALLERGIC ASTHMA AFTER EATING FRUITS
Researchers at the UPM
suggest that the interaction between two proteins can be the responsible for
the allergic asthma episodes after eating an infected fruit.
A research group of
the Centre for Plant Biotechnology and Genomics (CBGP) of Universidad
Politécnica de Madrid (UPM) conducted infection assays of commercial kiwis with Alternaria
alternataspores which is a pathogenic fungus involved in chronic asthma in
children. Researchers studied the behavior of this fruit and they found that
the infected kiwis had the major allergen of the fungus, although symptoms of
rot were not seen. This could trigger the involuntary ingestion of the fungus
found in this fruit causing an asthmatic crisis in people allergic to
Alternaria.
Alternaria alternata is a fungus that proliferates in fruit
and vegetables crops and also when are collected and are on sale for the final
consumer. A protein known as Alt a 1 and related to the virulence is found in
the spores, this protein is described as the major allergen of this fungus.
According to this research, this protein can be a major cause of childhood
asthma in US.
When a pathogen
infects a plant, the defense response is activated producing an increase of
certain proteins related to the defense (known as protein 5). Likewise, the
fungus increases the production of the proteins involved in attacks or
virulence. However, the symptoms of rot by Alternaria alternata are
not seen in some fruits, for example, in kiwifruit. All this can cause the
involuntary ingestion of the fungus when eating the fruit.
Researchers conducted
tests by infecting commercial kiwifruit with spores ofAlternaria alternata and
they detected the presence of Alt a 1, a protein of fungal virulence. Also,
researchers studied how this protein is involved in the activation of defense
protein 5 in kiwifruit. Fourteen days after the infection, the kiwifruits
showed a regular aspect without apparent development of the fungus, but through
tests conducted in lab (microscopy of specific staining fungus and Kiwi
proteins) they detected the presence of Alt a 1 in the pulp.
What is more, they
observed that this fungal protein is found in the same areas that the defense
protein of the kiwifruit. Using computer modeling techniques, they identified a
surface area in Alt a 1 susceptible to interact with the defense protein. In
that interaction, Alt a 1 is joined to a region of the protein 5 of the
kiwifruit causing a remarkable decrease of its defense activity. These results
reveal that Alt a 1 is an inhibitor of the defense proteins of family 5 which
is particularly important in processes of fungal infection.
Researchers did not
observed development of the fungus in kiwifruit, but they indeed detected the
presence of its major allergen through specific staining. From health point of
view, the presence of Alt a 1 in apparently healthy kiwis is important since Alternariais
described as a major cause of chronic asthma in children. These results suggest
that patients allergic to Alternaria can suffer an allergy
attack after eating infected kiwifruit.
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