Fossil fuel is believed to be derived from ancient lipid rich organic material such as spores and planktonic algae!
Rudolf Diesel used peanut oil as liquid fuels in internal combustion engines (1900)
Because of its low cost and easy availability, petroleum became the dominant energysource and petroleum diesel was then developed as the primary fuel for diesel engines
Petroleum and its derivatives fuels were in short supply in 1930 and hence in the 1930s and 1940s, neat vegetable oils were used in diesel engines under an emergency situation (Ma and M.A. Hanna, 1999. Biodiesel production: a review, Bioresource Technology 70 :1–15. ) During this period two approaches were used:
1- Hydrocarbons were produced in China by a Tung oil pyrolysis batch systemand used as liquid fuels
2- Fatty acids’ ethyl or methyl esters, obtained by transesterification oralcoholysis of vegetable oils
alcoholysis /al·co·hol·y·sis/ (al″kah-hol´ĭ-sis) decomposition of acompound due to the incorporation and splitting of alcohol
C- Cuticular lipids are protective agents
• Found in surface of all terrestrial plants.Crucial hydrophobic barrier to prevent H2O loss & protection
against pathogens & other environmental stresses. Contain:1- Cutin: polymer of 16 + 18 carbon hydroxyl fatty acids cross linked by esterification of their carboxyl groups to hydroxyl groups of neighboring acyl-chain.2- Wax esters: a mixture of long-chain fatty acids, and fatty alcohols and esters.
Why discuss the topic of:lipid Biosynthesis?
Lipids as:
- Biofuels- protective agents
- Signaling compounds
Fatty acids as signaling molecules
OXYLIPINSPlants Animals
LIPASE
COXs CYP450LOXs
arachidonic acid
LIPASE
arachidonic acid
CYP450
LIPASE
arachidonic acid
LOXs CYP450
LIPASE
arachidonic acid
COXs LOXs CYP450
LIPASE
arachidonic acid 20:4
Why discuss the topic of:lipid Biosynthesis?
Lipids as:
- Biofuels- protective agents
- Signaling compounds- Pharmaceutical
Fatty Acids and Health
Lorenzo’s oil ( a blend of trierucin/triolein)A cure to adrenoleukodystrophy (ADL), an X-linked disorder
Classes of Lipids
A. Major Class:The most abundant type are derived from fatty acid and glycerolipid biosynthetic pathway.
B. Minor Class:Derived from isoprenoid pathway and there are over 25000 isoprenoid compounds. Mostly are "Secondary metabolites" not found in all cells (not essential to growth).
Sterols, gibberellins, abscisic acid + phytol side chain of chlorophyll are from this pathway.
The Fatty Acid biosynthesis is a Primary Metabolic Pathway:in all cells, essential for growth. No mutation or inhibitors : lethal.
In plants plastids are the predominant site of FA biosynthesis
Fatty acids in animals and fungi are produce in the cytosol
Major fatty acids in plants
Fatty acids in plants, and most other organisms havea chain length of 16 or 18 carbons, and contain
one to three cis double bonds.Five major fatty acids:
16:016:3, make up over 90% of the acyl-chains of the
structural glycerolipids of all plant membranes18:118:218:3
** Never as Free Fatty acids in cells, instead, their carboxyl group is esterified or otherwise modified.They are esterified to glycerols “ glycerolipids”
Lipid Biosynthesis
18:1-ACP18:1 R-CoA
PLASTID
4:0-ACP
Acetyl-CoA ACP
12:0-ACP
14:0-ACP
18:0-ACP
16:0-ACP
P
P-CholineR RPMEMBRANE
LIPIDS
OILBODY
CYTOPLASM
CPT
R
RR
RR
PRR
R
ACP18:016:0
Malonyl-CoA
CO
CO
2
2
TAG
DAGAT
GPAT
LPAAT
PAP
ACCaseKASIII
THIOESTERASE
∆9-DESATURASE
6:0-ACP
8:0-ACP
10:0-ACPKASI
KASII
Lipid Biosynthesis
18:1-ACP18:1 R-CoA
PLASTID
4:0-ACP
Acetyl-CoA ACP
12:0-ACP
14:0-ACP
18:0-ACP
16:0-ACP
P
P-CholineR RPMEMBRANE
LIPIDS
OILBODY
CYTOPLASM
CPT
R
RR
RR
PRR
R
ACP18:016:0
Malonyl-CoA
CO
CO
2
2
TAG
DAGAT
GPAT
LPAAT
PAP
ACCaseKASIII
THIOESTERASE
∆9-DESATURASE
6:0-ACP
8:0-ACP
10:0-ACPKASI
KASII
MembraneEssential Constituent, of all cells:Vegetative cells of plant contain 5-10% lipid by dry weight, mostly found in membranes
Delineate the cell & its compartmentSite of essential processes such as light harvesting &
electron transport of photosynthesis
Membrane glycerolipids have fatty acids attached to both the Sn-1 and Sn-2 position of glycerol backbone. Polar headgroup attached to Sn-3 position.
Fatty Acids
Combination of polar and nonpolar -> amphipathic property of glycerolipids -> an essential property for the formation of membrane bilayer.
Membrane
glycerophospholipid has: 1- A polar region: glycerol, carbonyl oxygens of fatty acids, phosphate, and the polar head group .
2- Two nonpolarhydrocarbon tails of fatty
acids.
B: Carbon Storage:
Plant use reduced carbon derived from photosynthesis to store energy. Main forms of reserves are Carbohydrates, protein & oils. Oils most efficient form of energy storage carbons in Fatty acids are highly reduced (more than carbohydrates), and therefore oxidation of oils release twice as much energy as the oxidation of carbohydrates or proteins. Many seeds synthesize oil in developing seeds to act as energy source in germination. In some species up to 60% of seed dry weight is oil.
Lipid Biosynthesis
18:1-ACP18:1 R-CoA
PLASTID
4:0-ACP
Acetyl-CoA ACP
12:0-ACP
14:0-ACP
18:0-ACP
16:0-ACP
P
P-CholineR RPMEMBRANE
LIPIDS
OILBODY
CYTOPLASM
CPT
R
RR
RR
PRR
R
ACP18:016:0
Malonyl-CoA
CO
CO
2
2
TAG
DAGAT
GPAT
LPAAT
PAP
ACCaseKASIII
THIOESTERASE
∆9-DESATURASE
6:0-ACP
8:0-ACP
10:0-ACPKASI
KASII
Sn-1 Plants: mono and polyunsaturated 18carbons
B- Plant oil as an alternative source of biofuel:
Sn-2Sn-3 Animals: Saturated TAGS
Plant TAGs:
• Plant storage lipids are important components of human andanimal diets.
• Industrial use: detergents, paints, lubricants. Loosely definedas H2O insoluble compounds- extractable by organic
solvent such as chloroform.
Three positions of glycerol esterified with Fatty acid ->triacylglycerol (TAG) -> major form of lipids in TAG:
Fatty Acids in Common Vegetable Oilsacetyl-CoA
C4:0-ACP
C6:0-ACP
C8:00-ACP
C10:0-ACP
C12:0-ACP
C14:0-ACP
C16:0-ACP
C18:0-ACP
C18:1-ACP
C16:0
C18:0
C18:0 [C18:2, C18:3]
SoybeanCottonCanolaSafflowerSunflowerMaizeFlaxSesame
C- Cuticular lipids are protective agents
• Found in surface of all terrestrial plants.Crucial hydrophobic barrier to prevent H2O loss & protection
against pathogens & other environmental stresses. Contain:1- Cutin: polymer of 16 + 18 carbon hydroxyl fatty acids cross linked by esterification of their carboxyl groups to hydroxyl groups of neighboring acyl-chain.2- Wax esters: a mixture of long-chain fatty acids, and fatty alcohols and esters.
Fatty acids as signaling molecules
OXYLIPINSPlants Animals
LIPASE
COXs CYP450LOXs
arachidonic acid
LIPASE
arachidonic acid
CYP450
LIPASE
arachidonic acid
LOXs CYP450
LIPASE
arachidonic acid
COXs LOXs CYP450
LIPASE
arachidonic acid 20:4
Fatty acids as signaling molecules
Minor amount of fatty acid are precursors to hormone &Jasmonic acid (a component of signal transduction pathway)
Fatty acids as signaling molecules
Jasmonic acid (a component of signal transduction pathway)JA is a plant growth regulator derived form 18:3, and is capable of induction of plant defense genes, at low concentrations.
Biosynthesis and structure of jasmonate is very similar to that of eicosanoids that are central to inflammatory responses in mammals.
JA protects plants from insects
Fatty acids as signaling molecules
OXYLIPINSPlants Animals
LIPASE
COXs CYP450LOXs
arachidonic acid
LIPASE
arachidonic acid
CYP450
LIPASE
arachidonic acid
LOXs CYP450
LIPASE
arachidonic acid
COXs LOXs CYP450
LIPASE
arachidonic acid 20:4
AA treatment enhances resistance to Botrytis
0
0.4
0.8
1.2
1.6P = <0.001
∗
Mock AA
Lesi
on d
iam
eter
(cm
)
Mock AA
AA enhanced resistance to Botrytis is mediated via JA pathway
1000
JA (n
g/g
FW) 800
600
400
200
Mock AA 0
Mock AA
Lesi
on a
rea
(cm
2 )
P = 0.004
0
0.2
0.4
0.6
0.8
1 ∗
MockAA
Mock AA
0
1
2
3
4
AA
JA (n
g/g
f.w.)
Mock
Multimerized RSREs are sufficient to confer rapid responses to bothbiotic and abiotic stresses in vivo
RSRE = ATAACGCGTTTTTA4X RSRE LUCIFERASE
THUSRSRE is a functional motif involved
in primary stress responses
Rapid Stress Response Element (RSRE)
RSRE = ATAACGCGTTTTTA
4X RSRE LUCIFERASE
Time (min)
Bio
lum
inesc
en
ce
400
600
800
1000
1200
1400
1600
-45 5 55 105 155 205 255 305
W
4xRSRE Wounded Leaf
4xRSRE Systemic Leaf
Vector Control Wounded LeafBackground
Walley et al., PLoS Gent 07
AA elicits expression of4XRSRE:LUC
350
Bio
lum
inesc
en
ce
AAMock
100
150
200
50 100 150 200 250 300Time (min)
500
Fatty acids and disease
Lorenzo’s oil ( a blend of trierucin/triolein)A cure to adrenoleukodystrophy (ADL), an X-linked disorder
Fatty acids and diseaseScience 1998 Jun 5;280(5369):1607-10
Inhibition of a Mycobacterium tuberculosis beta-ketoacyl ACP synthase by Isoniazid
Fatty-acid synthase and human cancer:new perspectives on its role in tumor biology
Nutrition 2000 Mar;16(3):202-8
Science 2000 Apr 7;288(5463):140-3
Specialized fatty acid synthesis in African trypanosomes: myristate for GPI anchors.
Medium Chain Fatty Acidsacetyl-CoA
C4:0-ACP
C6:0-ACP
C8:00-ACP
C10:0-ACP
C12:0-ACP
C14:0-ACP
C16:0-ACP
C18:0-ACP
C18:1-ACPchloroplast/proplastid
C8:0C10:0
Free fatty acids
acyl-CoAs
Structurallipids
Storagelipids
{further desaturation}
endoplasmic reticilum
MCTs and their applicationComprised primarily of caprylic (8:0) and capric (10:0)Application:A: FoodFull and Pre-term infant formulaAthletic supplementsB: Nutrition/PharmaceuticalOral, enteral and IV nutrition:
Digested, and absorbed and transported rapidlyDietetic/low calorie food:
Oxidized rapidly in the organism and hence low tendency todeposit as body fat
Ketogenic, a diet traditionally given to drug resistance children with epilepsy to improve seizure controlControlling diarrhea and fat malabsorption in HIV-positive patientsPotentially, as part of ketogenic diet in slowing tumor growthC: IndustrialBiogradable lubricants and Biodiesel