Lecture 25- Ecological Microbial Diversity

Ecological diversity

The difference/similarity between how microbes interact with each other and their environment

metabolic capabilities

Ecological interactions are often defined by what ____________ an organism has, ex. can you generate energy using nitrate?

phylogeny, physiological differences, combination

However, we must also consider ______ and ________ as well. Ecological diversity is a _______ of all three of these factors.

shared functions, same ecological role

Microbes that perform these ___________ often have the ___________ in their environment.

Nitrogen, oxidation states

________ has multiple different _______, ranging from -3 to +5

harness this versatility

There are many organism which can ______________ to perform the metabolic process we talked about last lecture.

Diazotrophs

Microbes that fix nitrogen gas (N2) by converting nitrogen gas to ammonia (NH3)

Nitrifiers

Microbes that oxidize ammonia or nitrite (NO2-)

De-nitrifiers

Microbes that anaerobically respire nitrate or nitrate (NO3-) into gaseous form (NO, N2O, N2)

several microbial phyla

Nitrogen fixation is spread among _______________.

Diazotrophs

microbes that fix nitrogen gas (N2) by converting nitrogen gas to ammonia (NH3)

Nitrogenase

The enzyme which catalyzes the reduction of N2 to NH3

NifH

Dinitrogenase reductase, encoded by a single gene.Almost every organisms that has NifH fixes nitrogen

does not match

NifH phylogeny (relatedness) ______________ species phylogeny. This means that more distantly related species of prokaryotes share very similar NifH proteins.

horizontal gene transfer

Because NifH phylogeny (relatedness) does not match species phylogeny it indicates that NifH, and the metabolic trait of nitrogen fixation, is spread via ___________________.

inhibited, oxygen

Nitrogenase enzyme is ________ by the presence of ________. Each microbes which performs nitrogen fixation must overcome this barrier.

obligate anaerobes, avoid oxygen

Microbes that are listed in RED are _________, meaning they cannot live in the presence of oxygen. These microbes _______ to enable nitrogenase usage.

black, symbiotic relationship, regulate exposure to oxygen

Microbes that are listed in ________ have an established ___________ with another organism. These microbes live inside a host which provide nutrients to the microbe and __________________.

Symbiosis

A long term association between organisms of different species Best characterized in the root nodules of the plants, which may contain many different microbes.

The host cell

• Provides a hospitable environment

• Controls exposure to oxygen (O2).

• Provides a carbon source.The symbiotic diazotroph

The symbiotic diazotroph

Provides fixed nitrogen in the form of ammonia which the plant can use for metabolic processes.

mutually beneficial

Because both organisms provide something to the relationship it means it is _____________.

Nitrification

is the two-step process of converting ammonia to nitrate, producing energy.Ammonia (NH3) --> Nitrite (NO2-) --> Nitrate (NO3-)

ammoniamonooxygenase (AMO)

The first step of nitrification is performed by nitrifiers which use ________________________ to convert ammonia into nitrite.

amino groups, ammonia, high protein waste

Remember: Protein contain _________ which can be converted into _________ when digested. Therefore, these organisms are often found in ___________ such as soil and sewage treatment plants.

internal membrane stacks, evolutionary development

The first step of nitrification happens in __________ of microbe, an ___________>

nitrite oxidoreductase (NXR)

The second step of nitrification is performed by nitrifiers which use ______________ to convert nitrite into nitrate.

nitrite oxidizing bacteria, Proteobacteria

Most of the diversity of ___________ comes from the phylum __________.

internal membrane stacks

Within these cells the process also happens in ____________ of the microbe. These are once again an evolutionary development.

anaerobically respire

Organisms which perform denitrification _____________ nitrite and nitrate intro the gaseous forms.

facultative aerobes

Organisms that anaerobically respire nitrite and nitrate into the gaseous forms are __________, which can respire both oxygen and other compounds.

added to soils, greenhouse gases, climate change

These facultative aerobes are ___________ in agriculture to remove excess nitrate/nitrite from the soil. However they are _____________ which contribute to _________.

Complete denitrification, multiple enzymes

______________ of nitrite into nitrogen gas requires ________, as there are multiple to process.

chemoorganotrophs

Denitrifying bacteria are generally _________ which use an organic carbon source as an electron donor.

Partial denitrification

(doing some of the steps) is a wide-spread phenotype

Two Archaeal phyla, six bacterial phyla, denitrification

______________ and ______________ contain members which can perform ___________.

horizontal gene transfer.

This wide-spread presence of denitrifying enzymes in diverse phyla indicates the spread of these genes by ______________________.

physiological characteristics

Ecological diversity also includes the _________________ of an organism

Bdellovirbiro bacterivorous, preys

is a small Gram-negative bacteria which _________ on other cells. The name comes from the prefix Bacteri-, meaning bacteria and the suffix -vorous, meaning "to eat"

penetrates a host cell wall, replicates itself

B. bacterivorous _______________________, within the host cell it ________________, "eating" the cell's resources to do so.

Gram-negative bacteria

B. bacterivorous only attacks _____________, Gram-positive bacteria are unaffected

periplasm

Penetration takes place in the host cells ___________. The B. bacterivorous cell elongates and within 4 hours progeny are released. These progeny repeat the process, feeding on more of the bacteria in the environment.

not an obligate predator, without prey bacteria

B. bacterivorous is ________________, and can grow in complex, nutrient-rich environments _____________.

survival response

Predation is a ___________.