Goodness me, it's been a while since I've actually posted something. But not for a lack of interesting topics, science news, or ideas that have crossed my mind. In fact, I have at least a dozen draft blogs running right now. In due time I shall complete these drafts and post them - sooner rather than later - to keep up with my goal of an averaged post per week. But onwards and forwards with looking into the Immune System!
As the Autumn weather is really starting to kick in, and as I've been starting to spend more time indoors to get away from the rain, I've been hearing more sniffling, sneezing, and coughing - it's the cold season - particularly in areas with high numbers of people such as corporate offices, universities, colleges, schools, and coffee shops. For those of us in the temperate latitudes in the Northern Hemisphere, we're all familiar with the cold season and many of us will be getting the sniffles at some point.
This got me to thinking (by no surprise that I'm obsessed with primary productivity) about the immune system of plants. Surely, plants are exposed to diseases, viruses, and bacteria that deplete their immune systems, just as we are? But actually, plants don't have quite the same immune capabilities as many animals do. In fact, there are two types of immune responses: adaptive and innate. (See the Crash Course YouTube video below)
In the former, adaptive response is found in vertebrate animals and is a highly complex system that allows for an immunological memory to be stored so that after an initial exposure to a pathogen (think: viral, fungal, or bacterial illness), any subsequent attacks by the same pathogen is recognized and the immune response is enhanced. In humans, you may have heard of T-cells that stay in your body after you've been ill. These are "memory" cells and are the very reason humans bother with vaccinations - introducing a human body to a particular pathogen to prevent illness or disease - and are only valuable to vertebrate animals that have adaptive immune systems.
Now, the latter type of immune response, the innate or non-specific immune system, is evolutionarily an older system developed and utilized by plants, fungi, insects, and the more primitive multicellular organisms. The first response an organisms with an innate immune system has is physical, chemical, or biological. Once the invader is recognized by cellular mechanisms, responses differ depending on the organism that is reviewed - plants do not respond exactly the same way as an invertebrate - but there are similarities: inflammation, mucus production, chemical flooding, temperature change, or necrosis (the killing of cellular tissues). What's fascinating though, is that every class of pathogens that infect humans, can infect plants, it's just their response to it that is different.
Since I'm obsessed with primary productivity, obviously my personal interest is in looking deeper into the innate immune response of plants. However, another blog shall be created to go further in depth of plant pathology, for those that are interested. For the purposes of this blog, I shall attempt to keep it simple.
The innate immune system is distinguished by two pathways: 1) Extracellular recognition on the surface of the plant, and 2) Intracellular signaling within the cell of the plant.
Unlike adaptive systems found in animals, plants do not have mobile T-cells to engulf the pathogen. Instead, they have surveillance systems that are made up of receptors that detect the presence of a "foreign" pathogenic cell that allows for the innate immune system to respond. The plant then excretes specific physical (e.g. cuticle thickening) chemical (e.g. toxins) or biological (e.g. necrosis) responses to protect itself against the pathogen. The complexity of plant immune systems is based upon protein selection pressure, of which there are 56 potential immune elicitor proteins according to the University of Toronto. The molecular work being done to identify the genomic arena for plant pathogens is part of a whole field of work dedicated to plant pathology. Perhaps at a later date I shall blog about epigenetics and phenotypic plasticity. But for now, this is still pretty cool (or at least in my opinion) -- Just like humans, preservation in the form of survival is essential, and plants are no exception!
All organisms, regardless of the type or habitat use defense mechanisms to protect itself, and their immune systems are just one of many techniques designed to do that. How cool is that??
Human bodies, the body of a microbe, a plant, an insect, or the dog or cat in the neighborhood has a continually functional system that is designed to protect them from any harmful pathogen and it's working all the time. Perhaps overtime, as the natural cycle of time places those of us in the Northern Hemisphere at the entry of the cold season.
Be safe, stay healthy, and enjoy the shift in season, as the immune system continues to work its magic!
 |
| Source: http://www.eiu.edu/herc/coldfluprevention.php |
As the Autumn weather is really starting to kick in, and as I've been starting to spend more time indoors to get away from the rain, I've been hearing more sniffling, sneezing, and coughing - it's the cold season - particularly in areas with high numbers of people such as corporate offices, universities, colleges, schools, and coffee shops. For those of us in the temperate latitudes in the Northern Hemisphere, we're all familiar with the cold season and many of us will be getting the sniffles at some point.
This got me to thinking (by no surprise that I'm obsessed with primary productivity) about the immune system of plants. Surely, plants are exposed to diseases, viruses, and bacteria that deplete their immune systems, just as we are? But actually, plants don't have quite the same immune capabilities as many animals do. In fact, there are two types of immune responses: adaptive and innate. (See the Crash Course YouTube video below)
In the former, adaptive response is found in vertebrate animals and is a highly complex system that allows for an immunological memory to be stored so that after an initial exposure to a pathogen (think: viral, fungal, or bacterial illness), any subsequent attacks by the same pathogen is recognized and the immune response is enhanced. In humans, you may have heard of T-cells that stay in your body after you've been ill. These are "memory" cells and are the very reason humans bother with vaccinations - introducing a human body to a particular pathogen to prevent illness or disease - and are only valuable to vertebrate animals that have adaptive immune systems.
Now, the latter type of immune response, the innate or non-specific immune system, is evolutionarily an older system developed and utilized by plants, fungi, insects, and the more primitive multicellular organisms. The first response an organisms with an innate immune system has is physical, chemical, or biological. Once the invader is recognized by cellular mechanisms, responses differ depending on the organism that is reviewed - plants do not respond exactly the same way as an invertebrate - but there are similarities: inflammation, mucus production, chemical flooding, temperature change, or necrosis (the killing of cellular tissues). What's fascinating though, is that every class of pathogens that infect humans, can infect plants, it's just their response to it that is different.
Since I'm obsessed with primary productivity, obviously my personal interest is in looking deeper into the innate immune response of plants. However, another blog shall be created to go further in depth of plant pathology, for those that are interested. For the purposes of this blog, I shall attempt to keep it simple.
The innate immune system is distinguished by two pathways: 1) Extracellular recognition on the surface of the plant, and 2) Intracellular signaling within the cell of the plant.
 |
| Source: http://germzoo.blogspot.co.uk/2012/02/running-away-is-not-option-or-how.html |
All organisms, regardless of the type or habitat use defense mechanisms to protect itself, and their immune systems are just one of many techniques designed to do that. How cool is that??
Human bodies, the body of a microbe, a plant, an insect, or the dog or cat in the neighborhood has a continually functional system that is designed to protect them from any harmful pathogen and it's working all the time. Perhaps overtime, as the natural cycle of time places those of us in the Northern Hemisphere at the entry of the cold season.
Be safe, stay healthy, and enjoy the shift in season, as the immune system continues to work its magic!
Other Sources:
Gaffney, T., Friedrich, L., Vernooij, B., Negrotto, D., Nye,
G., Uknes, S., … Ryals, J. (2014). Requirement of Salicylic Acid for the
Induction of Systemic Acquired Resistance, 261(5122), 754–756.
Jones, J. D.
G., & Dangl, J. L. (2006). The plant immune system. Nature, 444(7117),
323–9. doi:10.1038/nature05286
Kwon, C.,
Bednarek, P., & Schulze-Lefert, P. (2008). Secretory pathways in plant
immune responses. Plant Physiology, 147(4), 1575–83.
doi:10.1104/pp.108.121566
McCann, H. C.,
Nahal, H., Thakur, S., & Guttman, D. S. (2012). Identification of innate
immunity elicitors using molecular signatures of natural selection. Proceedings
of the National Academy of Sciences of the United States of America, 109(11),
4215–20. doi:10.1073/pnas.1113893109
Ton, J. (n.d.).
The plant immune system: a multitasking regulator of parasitic and mutualistic
interactions. Publicationsarchive.hgca.com. Retrieved from
http://publicationsarchive.hgca.com/publications/documents/Jurriaan_Ton.pdf
Looking forward to more on this subject :)
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