aspirin and plants

Question 1

history of aspirin

Answer 1

-aspirin
-acetylsalicylic acid
-ASA

one of the first common use drugs

continues to be highly researched

Question 2

Willow (Salix species)

Answer 2

Indigenous Americans use for colds, influenza, indigestion

sumerian clay tablets describe willow bark for use in rheumatism

ancient Egyptians use leaf and bark as painkillers

chinese doctors use

hippocrates uses for women in labor, aches, and fever

willow leaf tea to ease childbirth pain

Question 3

chemical compounds in Willow

Answer 3

• astringent quality due to a glycoside called salicin
  -salicin breaks down into salicylic acid and a sugar in the intestine and liver

-other plants with salicylic acid or methyl salicylate

meadowsweet: spiraea ulmaria, salicin is also found in the meadowsweet flower

filipendula ulmaria

wintergreen: Gaultheria procumbens

Question 4

Ebers papyrus

Answer 4

an ancient egyptian medical refers to willow as an anti-inflammatory/pain reliever

Question 5

salicylic acid made from ________ by french scientists but it is found to irritate the gut

Answer 5

salicin

Question 6

what did Bayer find that adding ______ group to salicylic acid reduces its irritant properties

Answer 6

acetyl group

acetylation process

Question 7

aspirin use in modern medicine

Answer 7

• earliest use to treat hypertension with the greatest benefit seen in preventing heart attacks

then primary prevention tool to reduce the risk of stroke or risk of heart attack or death from cardiovascular causes

reduces risk of colorectal, stomach, an oesophageal cancers

Question 8

how is the name ‘ Aspirin’ broken down

Answer 8

“A” represents the added actyl-group

“spir” is derived rom Spiraea ulmaria (meadowsweet) which yields salicin

“in” was a common suffix used for drugs at the time of the first stable synthesis of acetylsalicylic acid

aspirin is the substitute for the salicylates, agreeable taste, free from unpleasant after effects

Question 9

Salicylic acid (SA)

Answer 9

-accumulates in both local and systemic tissue tissues (not the systemic signal)

removal of SA prevents induction of SAR

has a number of analogs/ conjugates

triggers a change in the cells redox potential –> this causes the translocation of NPR1 to the nucleus to activate SA-regulated genes

Question 10

NPR

Answer 10

non-expressor of PR genes

Question 11

what is systemic acquired resistance?

Answer 11

Systemic Acquired Resistance (SAR) is a type of induced defense mechanism in plants that provides long-lasting protection against a broad spectrum of pathogens, including bacteria, viruses, and fungi. Unlike direct defenses like physical barriers or pre-existing chemical toxins, SAR is a systemic response that occurs throughout the entire plant in response to a localized infection.

The process of SAR is initiated when a plant recognizes the presence of a pathogen through the detection of pathogen-associated molecular patterns (PAMPs) or other signals. This recognition triggers a signaling cascade that induces a systemic response in the plant, preparing it to defend against future attacks.

Question 12

salicylic acid

Answer 12

• has a time-of-day expression
  -peaks in the dark
  -consistent with the expression of genes affecting SA levels which also show circadian oscillations

-this occurs even when there is no pathogen attack

-under pathogen attack clock can be regulated by NPR1

Question 13

hypersensitive response (HR)

Answer 13

1. burst of oxygen-reactive species around infection site
2. synthesis of antimicrobial phytoalexins
3. accumulation of salicylic acid (SA)
4. directly kill and damage pathogens
5. strengthen cell walls, and trigger apoptosis
6. restrict pathogen from spreading
7. rapid and local

Question 14

systemic acquire resistance (SAR)

Answer 14

1. secondary response
   2.systemic
   3.broad range resistance
2. leads to pathogenesis-related (PR) gene expression
3. signals: SA-> JA, ethylene

Question 15

what are potential approaches? we could use to figure out what enzymes are responsible for producing SA

Answer 15

-radiolabelling studies
-genetic studies
-correlative studies (genomic)
-expression of genes/enzymes in a heterologous system
-gene silencing (VIGs) or genome editing (CRispr-CAS9)
-putting in new pathways which increase flux or siphon off compound into another pathway

Question 16

pathways of SA biosynthesis in plants?

Answer 16

(1) isotope feeding: experiments suggest that plants synthesize SA from cinnamate produced by PAL

(2) genetic studies: have indicated that the bulk of SA is produced from isochorismate

(3) genes PBS3 and EPS1 are identified as important for pathogen-induced SA production. encode enzymes catalyzing related, and possibly sequential, reactions in the synthesis of SA

Question 17

mutants affecting SA synthesis
-elevated SA accumulation
-mpk4 (MAP protein kinase 4): constitutive SA accumulation

reduced SA accumulation:
-eds1 (enhanced disease susceptibility 1): lipase homolog- immune receptor

pad4 (phytoalexin deficient 4): another lipase homolog

sid1 and sid2 salicylic acid induction- deficient): defects in chorismate pathway

Question 18

cross communication between hormone signalling pathways

Answer 18

provides the plant with a large regulatory capacity that may tailor its defense response to different types of attackers

the Sa, JA, and ET signalling pathways represent the backbone of the defense signaling network, with other hormonal signaling pathways feeding into it

Question 19

usage and value

Answer 19

-ASA valuable in the discovery of the mechanism cyclooxygenase (cox) 1 and 2 and the newer cox inhibitors which can be specific to one variant or the other
-COX enzymes produce prostaglandins

-the popularity of ASA declined in 1960’s as other drugs (ibuprofen, acetaminophen) came on line

Question 20

upon injury, phospholipase 2 (A2) releases different FA’s some of which are arachidonic acid