BIOC17H3 Lecture Notes - Lecture 4: Proteobacteria, Organelle, Micelle
5 Jul 2018
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- Problem: microbes have complex nutrients, env. Conditions, need interactions with
other microbial communities, can be intracellular parasites (get their nutrients,
habitat from a host; bacteria that need to grow inside a Eukaryotic cell, a bacteria that
needs to grow in another bacteria)
- About 0.1-10% of microbial species are cultivable
- Molecular biology helped solve this crisis used rRNA to detach from the needs of pure
culture in certain applications to identify bacteria
oWhat did they do: extract all DNA from an env. Sample/microbial community
use PCR and primers to amplify the 16s RNA, amplified all the RNA found what
types of them are viable in these env. Samples then clone in bacteria (eg. E.
Coli) then look at the DNA and compared to see if they were different
oGet samples amplify 16S rRNA w/ PCR clone in E. Coli amplify that gene
extract it compare and construct phylogeny
oThen used comparative
analysis of 16S rRNA
gene from other species
showed presence of
signature sequences:
short conserved
sequences that can be
highly diagnostic of
group related organisms
- Problem: these methodologies
only tell what microbes are
there (good for
understanding/identifying
diversity in nature)
-Metagenomics: which genome
in that community resembles
other microbe
oIs the sequencing and analysis of genes from microbial populations w/o the need
for culturing
oAsk: what is there, what genes encode for what enzymes, what are they doing,
how are they doing it, potential biotech use
- Genes and molecular structures from uncultured MO has potential in the development
of novel biocatalysts for industrial and medical applications
- Before these approaches were established in t 1994, there were 13 divisions of
microbes
oAfter the metagenomics technique, the # of divisions that were increased to 36
many were uncultured
o2005: 54 uncultured, 80 total
o2006: 100 divisions, 70 uncultured
- most of eukarya is microbial
Public Perception of MO Changed
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- originally thought to be not diverse, few in numbers, primitive, cause disease
- find: more numerous and diverse than any other kind of organisms
o1x10^7-9 estimate # of microbial species on earth
o1x10^30 is the estimated # of microbes on earth
comprise: 50%
of biological
carbon mass,
90% of
biological
nitrogen mass
on Earth
- can be found in every env.:
soil, rocks, roots, in the earth,
compost, toxic water etc.
oSoil: more microbes in
scoop of soil than
humans in the planet
(1x10^9 microbes/gram
of soil)
oOceans: 2x10^6 diff.
bacterial species, 10^9
microbes/L of
seawater
Sargasso Seas sequencing in 2005
oSee microbial life in 3000m below the ice
Proves that those microbes existed when Antarctica wasn’t covered in ice
They evolved in different ways (eg. Have enzymes that can work at low
temperatures)
oVenter: are trying to see the minimum requirement that a cell will need to
survive
- HMP
oAim to see what cells are living with us
oEg. Their metabolic activity helps us (eg. More activity than our liver), help our
immune system detect pathogens,
oThere is more bacteria genetic material on the human body, than there are
human cells
oHave 1*10^14 MO in our gut
Helps absorb nutrients, break them down, occupy space to prevent
pathogens from surviving there
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If treat our flora with antibiotics, can open place for pathogens
So function:
protection (compete w/ pathogens for nutrients and space in
body; produce antimicrobials and modify the host env. making it
less suitable for pathogens),
structural function (induces the development and function of the
host immune system),
metabolic function (synthesis of vitamins, digestion of nutrients,
nutrients absorption)
if microbiota have died, can get fecal transplants from people related to
you
Microbial survival feats
- can survive 5 megarads of gamma radiation (10kx more than humans killing dose)
-can survive 8000 atmosphere
-some can grow from pH of 0-11.4, -15*C to 121*C, 1300 atm, 5.2M NaCl
- very well accepted that microbes were the first forms of life on earth and played a role
in transforming the earth to make it more open for other forms of life
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Conditions, need interactions with other microbial communities, can be intracellular parasites (get their nutrients, habitat from a host; bacteria that need to grow inside a eukaryotic cell, a bacteria that needs to grow in another bacteria) Molecular biology helped solve this crisis used rrna to detach from the needs of pure culture in certain applications to identify bacteria: what did they do: extract all dna from an env. Sample/microbial community use pcr and primers to amplify the 16s rna, amplified all the rna found what types of them are viable in these env. Samples then clone in bacteria (eg. e. Showed presence of signature sequences: short conserved sequences that can be highly diagnostic of group related organisms. Problem: these methodologies only tell what microbes are there (good for understanding/identifying diversity in nature) Genes and molecular structures from uncultured mo has potential in the development of novel biocatalysts for industrial and medical applications.
