Microbiology: Food Supply Chain (exam 2)

What stresses affect the FSC?

Abiotic factors (storms) and biotic factors (infections, spoilage)

Important of FSC

it is fragile and complex (COVID showed us), the food needs to be consumed and purchased, and agriculture is seasonal and exposed to stresses

More than ½ of the FSC can affect

How can abiotic factors affect the FSC?

a storm disrupts agriculture production, transportation of goods, and no power

What FSC processes were affected by microorganisms during COVID 19?

• Labor needs

• ecological and climate risks to crops

• livestock and poultry disease threats

• transportation bottlenecks

What FSc processes were affected by covid but not by microorganisms?

• concentration of Agri-Food production, manufacturing and distribution (relying on big companies)

• trade disruptions

How do labor needs affect the FSC?

contagious diseases can lead to labor shortages,

lead to the closure of food processing → massive disruptions of the supply chain

higher prices

transportation can be affected by illness

Where can microbes disrupt the supply chain?

Some examples are crop production, animal production, animal feed production, retail stores, consumer storage & preparation

What are some ecological climate risks to crops?

crop diseases caused by microorganisms (most caused by fungi)

• wheat rusts

Most common wheat diseases?

leaf rusts, fusarium head blight, triici blotch

How does leaf rust occur?

this is a wheat disease where the fungus has 2 hosts

the first cycle is on wheat and then transfers to meadow rue; it is dependent on the plants being in the vicinity of each other

What are some ways to stop leaf rust?

Crop rotation, breed resistant to fungus wheat plants

How does livestock and poultry affect the FSC?

animal disease (severe and can spread throughout the whole agriculture industry

lead to lower food production

What is an effective method of slowing/ stopping a virus?

create a vaccine against virus or cull any infected herds

not a good answer: treating with antibiotics

What do cells need for growth/ division?

energy, carbon, other nutrients, appropriate environmental conditions

What are examples of energy used for growth?

light, chemicals

What are examples of carbon used for growth?

CO2, CH4, organic chemicals

some source of carbon is needed to make organic carbon and all different cell components

What are examples of other nutrients cells use for growth?

NCHOPS (nitrogen, phosphorus..)

Macronutrients

NCHOPS and are needed in high quantities (depends on organism)

How do cells get carbon?

organic compounds (protein), carbon dioxide, methane

How do cells get nitrogen?

get from amino acids, N2 fixers (nitrates or ammonia), assimilated forms

Micronutrients

needed in tiny amounts (0.01-1%) but ESSENTIAL

magnesium, potassium, iron, calcium, sodium

How do cells transport their micronutrients?

cells have separate transport mechanisms for all of them

Magnesium (micronutrient) function

stabilizes ribosome, needed for ATP dependent reactions

ANYTHING that uses ATP needs magnesium to help it bind to the enzyme

Potassium (micronutrient) function

main cellular cation to balance out charge

Iron (micronutrient) function

needed for many enzymes (metabolism)

Calcium (micronutrient) function

not essential for all cells

Sodium (micronutrient) function

hot essential for all cells

What is the difference between a micronutrient and a trace element?

the concentration: micronutrients don’t need a lot of themselves but still need it or some

Trace elements

needed in small quantities (few molecules per cell) but still very important

OVERALL POINT: microbes will spend a lot of energy to get them into the cell

What are some examples of trace elements?

Boron, chromium, cobalt, copper, zinc, tungsten, nickel, selenium, molybdenum, maganese

specific requirements vary per microorganism

How do trace elements help the cell?

help the active site of enzymes carry out its reaction (in coenzymes and cofactors)

process of iron acquisition (getting into the cell) IN ECOLI

Iron is binded to a siderophore → ,makes its own specific porin to allow iron to pass through the cell membrane → ABC transporter to get inside of the cell (recognition Fep B, transporter Fep D, ATPase Fep C) → cell has iron, reduces it and used it for metabolism

Siderophores

small molecules that bind iron

Growth Factors

not elements they are organic compounds needed by some cells because they can’t make them (get through diet)

How do microbes get food?

1. absorptive via transport proteins (all microbes)

2. endocytosis (eukaryotic microbes)

   sub categories of endocytosis

   • phagocytosis

   • pinocytosis

What is endocytosis?

cells take in substances from outside of the cell by engulfing them in a vesicle

the process where something binds the membrane → goes to a clathron coated pit → goes into cell as an endosome PH DROPS on endosome → nutrients are then digested, transported, released into the cell

What is phagocytosis?

engulfs large solid particles

mostly used when talking about the immune system

pinocytosis

a process by which the cell takes in the fluids along with dissolved small molecules.

What if food is a gas, how can it be concentrated?

Gas is membrane permeable, goes right into cell and floats out

How is oxygen transported?

hemoglobin is in our red blood cells and binds to O2 molecule

Explain how gases are captured (enzymes and cofactors)

When high concentr. of O2 in lungs → hemogl. binds to O2 molecul. → binds to red blood cell (erythrocyte) → rbc goes through body to muscles where there is less O2 and goes into cells → bound by things inside cells like (cytochromes → to mitochondria)

What if food is too large to transport?

bacteria sends enzymes (exoenzymes) to break down the polymers to monomers → brings in monomers

What are common polymers?

cellulose, proteins, lignin chitin

where do microbes get food?

1. soluble nutrients (saprobes) (take stuff from the environment and bring it in)

2. other cells (predators and parasites)

where do the macronutrients go?

they are metabolized to make more cellular components

simple elements → structures in cell

food is a…

macronutrient

Nutritional classification

source of energy to fuel cell functions

source of carbon

source of electrons - need high energy e- and energy in the form of ATP and other chemical phosphates

chemotroph

chemical energy

phototroph

light energy

autotroph

CO2 carbon dioxide

heterotroph

organic compounds

lithotroph

inorganic chemicals

organotroph

organic chemicals

four most common groups in nature

photoautotrophic lithotrophs

photoheterotrophic organotrophs

chemoautotrophic lithotrophs

chemoheterotrophic organotrophs

photoautotrophic lithotrophs

energy source: light

carbon source: CO2

e- source: inorganic (H2O or H2S)

ex: plants, cyanobacteria, some purple / green bacteria

photoheterotrophic organotrophs

energy source: light

carbon source: organic compounds

e- source: organic compounds

ex: some purple / green bacteria

chemoautotrophic lithotrophs

energy source: chemicals (Fe, Mn, H2, NH3, H2S)

carbon source: CO2

e- source: inorganic compounds

ex: bacteria, MANY archaea

chemoheterotrophic organotrophs

energy source: organic compounds

carbon source: organic compounds

e- source: organic compounds

ex: most bacteria, some archaea

what does nutritional classification ignore about bacteria?

ignores that certain bacteria has needs for other nutrients besides electron source and carbon energy

What is the difference between trace elements and growth factors?

growth factors are organic compounds (both of these are required in small amounts)

Isolation techniques

simple plating- plate everything there

enrichment culture

simple plating

selects for fastest growing, best adapted to those conditions

use a medium that you think will support a lot of stuff

enrichment culture

stacking deck in your favor

manipulating the nutrient conditions and stack in your favor

What are pros of simple plating (or tube culture)?

may be able to isolate colonies

What are cons of simple plating?

microbe must grow on medium

competition between microbes

hard to select desired microbe

What is a pro of enrichment culture?

can select for desired metabolic capacity?

What is a con of enrichment culture?

will only get certain types

What are the types of media?

differential and selective

differential media

allows us to identify microbes by a reaction in the medium

everything can grow on the plate but there is a way to detect what you are interested in

selective medium

favors the growth of some microbes (only one can grow)

every medium is selective

syntrophy

cooperation between organisms (dependent on one another)

why cant we isolate some organisms?

when trying to culture them individually they don’t survive because they don’t have partners they depend on

Other growth requirements

presence of other microbes

nutrient concentration

unique microenviornments

growth on surface

Defined media

know everything that goes into it AND you know exact amounts you put in

complex media

know what it is and how much you added but don’t know everything that’s in it