#38 - Mar 2020 - Garden Stuff - © Sandy Lang - slang@xtra.co.nz
VIRUSES (written as COVID-19 was coming our way)
March/April: Early/mid-autumn. Still some good weather to go. Harvest late summer crops, establish winter crops while it’s still warm. We’re all thinking about viruses. What are they…?
Microbiomes: Microorganisms are among the earliest life forms. Very small, reproduce very fast, evolve very fast. Most are free-living but all plants and animals have their own microbiomes – communities of microorganisms living on them and in them.
Our own microbiomes are about ten microorganism cells for every one human cell – we’re vastly outnumbered. But microorganisms are small, so your load of alien cells is only about 1.5 kg. You couldn’t live without your microbiome. It helps you digest food and protects you from infection, plus heaps more…
Good and bad: There are six different kinds of microorganism: •bacteria, •archaea, •fungi, •algae, •protozoa and •viruses. For many 1,000s of years we’ve used bacteria and fungi to preserve our food and to improve its taste. Where would we be without yogurt, cheese, bread, salami, wine and beer?
And where would we be without diseases? Our diseases are mostly caused by bacteria (strep throat) and viruses (colds, flus) but a few by protozoans (meningitis) and fungi (thrush).
This said, less than 1% of all microorganisms are ‘bad’ and more than 99% are ‘good’. But there are no ‘good’ viruses. What is a virus…?
Viruses: A virus is a small infectious agent that multiplies only inside the cell of another living organism. Viruses infect all life forms, animals, plants and other microorganisms.
Non-living - Viruses are generally regarded as 'non-living'. But how do you define 'alive'…?
Usually three key questions. (1) Does it have its own machinery to replicate? No - to replicate, a virus must hijack the reproductive machinery a host cell.
(2) Does it grow bigger, then divide to multiply? No – a virus doesn’t grow. It forces a host cell to manufacture and assemble all its components.
(3) Does it have a metabolism? No - a virus doesn’t consume any energy. It hangs around till it contacts the right kind of cell to infect.
So, a virus is different from all other organisms.
CoVs: Most viruses infect the cells of a particular species but coronaviruses (CoVs) are ‘zoonotic’ – they jump from animals to people.
In people they cause mild illnesses (colds) but also severe ones - MERS-CoV (ex-camels), SARS-CoV (ex-civet cats)...
...and now we have SARS CoV-2 (animal source yet unknown, bats?) which causes the coronavirus disease COVID-19.___________________________________
VIRUSES (written as COVID-19 was coming our way)
March/April: Early/mid-autumn. Still some good weather to go. Harvest late summer crops, establish winter crops while it’s still warm. We’re all thinking about viruses. What are they…?
Microbiomes: Microorganisms are among the earliest life forms. Very small, reproduce very fast, evolve very fast. Most are free-living but all plants and animals have their own microbiomes – communities of microorganisms living on them and in them.
Our own microbiomes are about ten microorganism cells for every one human cell – we’re vastly outnumbered. But microorganisms are small, so your load of alien cells is only about 1.5 kg. You couldn’t live without your microbiome. It helps you digest food and protects you from infection, plus heaps more…
Good and bad: There are six different kinds of microorganism: •bacteria, •archaea, •fungi, •algae, •protozoa and •viruses. For many 1,000s of years we’ve used bacteria and fungi to preserve our food and to improve its taste. Where would we be without yogurt, cheese, bread, salami, wine and beer?
And where would we be without diseases? Our diseases are mostly caused by bacteria (strep throat) and viruses (colds, flus) but a few by protozoans (meningitis) and fungi (thrush).
This said, less than 1% of all microorganisms are ‘bad’ and more than 99% are ‘good’. But there are no ‘good’ viruses. What is a virus…?
Viruses: A virus is a small infectious agent that multiplies only inside the cell of another living organism. Viruses infect all life forms, animals, plants and other microorganisms.
Non-living - Viruses are generally regarded as 'non-living'. But how do you define 'alive'…?
Usually three key questions. (1) Does it have its own machinery to replicate? No - to replicate, a virus must hijack the reproductive machinery a host cell.
(2) Does it grow bigger, then divide to multiply? No – a virus doesn’t grow. It forces a host cell to manufacture and assemble all its components.
(3) Does it have a metabolism? No - a virus doesn’t consume any energy. It hangs around till it contacts the right kind of cell to infect.
So, a virus is different from all other organisms.
CoVs: Most viruses infect the cells of a particular species but coronaviruses (CoVs) are ‘zoonotic’ – they jump from animals to people.
In people they cause mild illnesses (colds) but also severe ones - MERS-CoV (ex-camels), SARS-CoV (ex-civet cats)...
...and now we have SARS CoV-2 (animal source yet unknown, bats?) which causes the coronavirus disease COVID-19.___________________________________