About microscopic forms of life, including Bacteria, Archea, protozoans, algae and fungi. Topics relating to viruses, viroids and prions also belong here.
Chloroplasts in spirilla
They are bacteria! They do not have any organelles. What are you talking about?
Patrick (whoI prefers E. coli)
I have a favourite enzime. But i will not share it
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter
I will indeed be interested to see anything that proves this... Spirilla are Gamma proteobacteria, which are not photosynthetic as far as I know.
Any URL or something to prove me wrong? I was leafing through the pages about spirilla in the Bergey's yesterday and I would have noticed something as obvious as chlorophyll in this genera.
But I am always ready to learn something new.
I have my Bergey's on my lap, bacteria from the different genera of spirilla are definitely not autotrophs.
No chlorophyll. That would have been listed as one of the main characteristics of the genus if it was. Too bad for your teacher. And I feel better about my microbiology knowledge. But there are lot of uncertainities in the genus, maybe I missed something, but I really do not think so.
So good luck to challenge me
It's funny. They tell us that we're paying for an education in college, not for the diploma. I've learned more about biology at this forum (and my outside reading) than I have in my two years (so far, I have a long way to go ) of college.
E. Coli is a neat microbe to study. It reproduces very quickly, so they are easy to study. I know it lives in our intestines as symbiotes, but what does it do for us? An old professor said it was Vitamin K, but I've heard that might not be correct.
Yes E. coli is a nice bacterium, but rather that symbiotes it is often referred to as a commensal: Sharing the same meal but without negative or positive interactions.
In fact it has both, I have also heard about the vitamin K, but I don't know if it is E. coli or another of the bacteria in our gut that produces it.
Our bacteria are also essential to the correct fonctions of our intetsines. In fact, axenic mice have a lot of problems of digestion. Mainly because the mucus lining their intestine is not fluid enough, so that is one more role for the intetsinal flora. And of course the role our flora resist to the introduction of new microbes (by using the ressources) thus protecting us from pathogens.
But I am mainly working with the nasty sides of E. coli like resistance to antibiotic and pathogenesis, and how all this evolves. That is where I like to work on a fast and easy growing bacteria.
Go on on the forum, your teachers do not know everything, here you may find some knoledgeable person.
I like your signature makes me feel good: I have a lot of culture (growing in the incubator, though )
Hmm. Now that you mention it...here is what the professor said as best I remember word for word:
"E. Coli shares a mutualistic symbiosis with us as long as it remains in the gut. It produces Vitamin K, which is important in blood clotting. However, if it moves out of the digestive tract, it can cause serious infections, especially if it moves into the urniary tract."
I don't know if this is correct or not, but that's what I was taught. The professor's background was in human genetics, a discipline fairly distant from microbiology...maybe you can shed some light on this?
Not entirely correct.
In fact it is rather hard to say that E. coli in general is such thing as a pathogen or a symbiont. Beteween different strains of E. coli the genome size can vary up to 20%. And you can find strains that are responsible of pretty nasty diseases without ever leaving the digestive tract. Genomic studies seem to prove that Shigella spp. are nothing more than E. coli with a plasmid carrying some nasty virulence genes.
And a study in France up to 20% of the E. coli carried by healthy people could be defined as potentially highly pathogenic.
E. coli can cause urinary tract infections (it is relatively easy to move from the digestive tract to the urinary one, mostly with women) but can also move in the blood of immunocompomised people (cancer patients, HIV, elderly, newborn...) and kill. The famous E. coli O157:H7 can move to the blood (around 1% of infected people) then go to the kidney to cause a symptom I can not name in english in 30% of these infortunate people. Most would then die, the survivor would keep kidney malfunctions for the rest of their lives.
In fact urinary tract infections (UTI) are far from being the worse you can expect (and if you eat cranberries you reduce significantly the risk of UTI, by blocking the adhesion mechanisms of the bacteria to the epithelium.
But a diverse microbial flora is necessary for a good health, and somme studies suggest that a nearly aseptic way of life may even increase the probability of auto-immune diseases.
By the way E. coli is only a minor bacteria in our gut, it is just the major aerobic one, but aerobic bacteria represent less than 1% of our total flora.
Thanks for clearing that up. Yes, I've heard about the H7 strain. What does the alphanumeric designation mean? Where did it come from?
Also, what does 20% difference in genome mean? Is it similar to the 99.x% of DNA that we share with other primates?
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