discovery occurance chemical structure of abssisic acid histroy of ABA its chemical composition its biosynthesis mutants used for ABA and its physiological role of ABA
The biosynthesis of the main auxin in plants (indole-3-acetic acid [IAA]) has been elucidated recently and is thought to involve the sequential conversion of Trp to indole-3-pyruvic acid to IAA. However, the pathway leading to a less well studied auxin, phenylacetic acid (PAA), remains unclear. Here, we present evidence from metabolism experiments that PAA is synthesized from the amino acid Phe, via phenylpyruvate. In pea (Pisum sativum), the reverse reaction, phenylpyruvate to Phe, is also demonstrated. However, despite similarities between the pathways leading to IAA and PAA, evidence from mutants in pea and maize (Zea mays) indicate that IAA biosynthetic enzymes are not the main enzymes for PAA biosynthesis. Instead, we identified a putative aromatic aminotransferase (PsArAT) from pea that may function in the PAA synthesis pathway.
The biosynthesis of the main auxin in plants (indole-3-acetic acid [IAA]) has been elucidated recently and is thought to involve the sequential conversion of Trp to indole-3-pyruvic acid to IAA. However, the pathway leading to a less well studied auxin, phenylacetic acid (PAA), remains unclear. Here, we present evidence from metabolism experiments that PAA is synthesized from the amino acid Phe, via phenylpyruvate. In pea (Pisum sativum), the reverse reaction, phenylpyruvate to Phe, is also demonstrated. However, despite similarities between the pathways leading to IAA and PAA, evidence from mutants in pea and maize (Zea mays) indicate that IAA biosynthetic enzymes are not the main enzymes for PAA biosynthesis. Instead, we identified a putative aromatic aminotransferase (PsArAT) from pea that may function in the PAA synthesis pathway.
Plant hormones are naturally occurring organic substances that affect physiological processes. There are five major groups of plant hormones, such as auxins, gibberellins, cytokinins, abscisic acid and ethylene. In this presentation deals with Cytokinins with its biosynthesis, transport, pathways and physiological effects.
the presentation encompasses auxin synthesis, conjugation, degradation, polar and lateral transport and signalling and how all of these together have a bearing on programming and design of the whole plant
ABA is a 15-C Sesquiterpene compound Composed of three isoprene residues Cyclohexane ring with keto, one hydroxyl group, a side chain with a terminal carboxylic group.
Chemical name Abscisic acid; (2-cis,4-trans)-5-(1-Hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexen-1-yl)-3-methyl-2,4-pentadienoic acid.
Plant hormones are naturally occurring organic substances that affect physiological processes. There are five major groups of plant hormones, such as auxins, gibberellins, cytokinins, abscisic acid and ethylene. In this presentation describes about abscisic acid with its biosynthesis, transport, pathways and physiological effects.
Plant hormones are naturally occurring organic substances that affect physiological processes. There are five major groups of plant hormones, such as auxins, gibberellins, cytokinins, abscisic acid and ethylene. In this presentation describes about ethylene with its biosynthesis, transport, pathways and physiological effects.
Meaning of Florigen
Characteristics of Florigen
Mechanism of action
Production of inflorescence meristem
Other functions of Florigen
Mechanism of action during other functions
thish is most helpful presantation on phosphate metabolism in plant
>importance phosphorus in plant
>phosphorus uptake in plant
>energy reaction photosynthesis
>Phosphorus Deficiency symptoms
Abscisic acid (ABA) is a plant hormone that regulates numerous aspects of plant growth, development, and stress responses. ABA-deficient mutants from various plant species display reduced seed dormancy and wilty phenotypes, highlighting that these crucial ABA functions are conserved in the plant kingdom.
Plant hormones are naturally occurring organic substances that affect physiological processes. There are five major groups of plant hormones, such as auxins, gibberellins, cytokinins, abscisic acid and ethylene. In this presentation deals with Cytokinins with its biosynthesis, transport, pathways and physiological effects.
the presentation encompasses auxin synthesis, conjugation, degradation, polar and lateral transport and signalling and how all of these together have a bearing on programming and design of the whole plant
ABA is a 15-C Sesquiterpene compound Composed of three isoprene residues Cyclohexane ring with keto, one hydroxyl group, a side chain with a terminal carboxylic group.
Chemical name Abscisic acid; (2-cis,4-trans)-5-(1-Hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexen-1-yl)-3-methyl-2,4-pentadienoic acid.
Plant hormones are naturally occurring organic substances that affect physiological processes. There are five major groups of plant hormones, such as auxins, gibberellins, cytokinins, abscisic acid and ethylene. In this presentation describes about abscisic acid with its biosynthesis, transport, pathways and physiological effects.
Plant hormones are naturally occurring organic substances that affect physiological processes. There are five major groups of plant hormones, such as auxins, gibberellins, cytokinins, abscisic acid and ethylene. In this presentation describes about ethylene with its biosynthesis, transport, pathways and physiological effects.
Meaning of Florigen
Characteristics of Florigen
Mechanism of action
Production of inflorescence meristem
Other functions of Florigen
Mechanism of action during other functions
thish is most helpful presantation on phosphate metabolism in plant
>importance phosphorus in plant
>phosphorus uptake in plant
>energy reaction photosynthesis
>Phosphorus Deficiency symptoms
Abscisic acid (ABA) is a plant hormone that regulates numerous aspects of plant growth, development, and stress responses. ABA-deficient mutants from various plant species display reduced seed dormancy and wilty phenotypes, highlighting that these crucial ABA functions are conserved in the plant kingdom.
When food containing, lignan precursors are consumed they are converted to the enterolignans, enterodiol and enterolactone, by bacteria that normally colonize the human intestine.
Enterodiol and enterolactone have weak estrogenic activity but may also exert biological effects through nonestrogenic mechanisms.
Because enterodiol and enterolactone can mimic some of the effects of estrogens, their plant-derived lignan precursors are classified as phytoestrogens.
Lignan precursors that have been identified in the human diet include pinoresinol, lariciresinol, secoisolariciresinol, matairesinol, and others
Leeuwenhoek described microorganism as Animalcules. Prokaryotes. Euk.pdfrbjain2007
Leeuwenhoek described microorganism as? Animalcules. Prokaryotes. Eukaryotes. Protozoa.
Which of the following was not mentioned as a central pathway for glucose metabolism? Entner-
Doudoroff pathway. The Pentose Phosphate way. Glycolysis. Fermentation. Answers A and B.
In a health Gram negative cell, which of these would you expect to be the most exterior to the
cell? Lipid A. O-side chain. ATP synthase. Secondary active transport proteins. Axial filaments
would be associated with: Flagella on a bacillus. Biofilm construction. Spirochete motility. Gram
negative outer membranes. N-Acetyl Glucosamine associates with which of the following? N-
acetyl numeric acid only. N-acetyl numeric acid and N-acetyl glucosamine N-acetyl glucosamine
and technical acid. N-acetyl numeric acid and lipotechoic acid. Leeuwenhoek examined rain and
pond water for microorganisms. He found some bacteria in one sample while the other did not
contain any life. The independent variable in this procedure was: The presence or absence of
bacteria. Where the water was obtained from. How long the water was allowed to be examined
on his scope. The possibility that the bacteria in a sample was introduced by the microscope
itself.
Solution
14. a (Animalcules)
Leeuwenhoek observed micro-organisms for the first time in microscope. They appeared to be
little animals to him so he called them animalcules. These descriptions were made for the first
time which made him the first microbiologist.
15. b. Pentose Phosphate pathway
Glycolysis and Fermentation are central pathways for carbohydrate metabolism for almost all
aerobes and Anaerobic organisms. ED pathway uses enzymes like 6-phospho gluconate
dehdrogenase and convert glucose to pyruvate in organisms like Pseudomonas. Pentose
Phosphate pathway is an alternate glucose oxidation pathway to produce NADPH rather than
being a central metabolic pathway,
16. b. O-specific polysaccharide chain
O-specific poly sccharide chain is the outer most part of outer membrane of Gram Negative cell
wall. Gram negative cell wall has has two membranes outer and inner separated by a periplasmic
space filled with Lipoproteins.
17. c. Spirochaete motility
Spirochetes are spiral cells contain an axial filament wrapped around them. They are similar to
flagella and are used for motility of the organism.
According to Chegg\'s policies only first 4 questions are to be answered. If you have multiple
questions please post them as groups 4 questions related to each other..
Content:
Introduction
History
Chemistry of artemisinin
Structural activity relationship of artemisinin
Mechanism of action
Drug interactions
Malaria is a very common disease. This probably originated in Africa around 30 million years ago.
In 1600s first treatment to malaria was recorded in Peru where native tribes used bitter bark of cinchona, to reduce the fever and pain.
In 1897 Sir Ronald Ross described female anopheles mosquito as the vector of the disease.
In 1950s the disease rebounded largely due to emergence of parasites resistant to drugs like chloroquine.
In 1967 a plant screening research program code named “Project 523” was set up in China by the People’s liberation army ordered by Mao Zedong at the request of North Vietnamese.
Under able leadership of Dr. Y. Tu more than 2000 herbs preparations were investigated . Out of which 640 herbs were hits.
The turning point came when Sweet wormwood extract showed a promising degree of inhibition in mouse model.
Although the progress was not smooth as the observation was not reproducible in subsequent experiments.
During cultural revolution no clinical trials were performed so Dr. Tu bravely volunteered to the first trials.
In Hainan first official trials happened on malaria patients. The patients showed much better result than chloroquine (Test samples).
Encouraged by this outcome, she moved on to investigate and isolated the pure compound of Artemisia.
In 1972 a colorless crystalline substance with a mol wgt. of 282 Da, having molecular formula of C15H22O5 was isolated. The molecule was named as Qinghau su (Artemisinin) from the leaves of Sweet wormwood scientifically known as Artemisia annua, family Compositae.
Dr. Y. Tu was awarded with Lasker DeBakey clinical medical research award in 2011 and finally the Nobel Prize in physiology and medicine of artemisinin in 2015.
SAR OF ARTEMISININ
Tetracyclic structure with a trioxane ring and a lactone ring.
Trioxane ring contains a peroxide bridge, the active moiety of the molecule.
MOL. FORMULA: C15H22O5; MOL .MASS: 282.332
Presence of a ‘Trioxane’ moiety which consists of the endoperoxide & doxepin oxygens that is evidently displayed by a simplified version of 3- aryltrioxanes.
Modification of 10th position ‘C’ gives a powerful derivative compared to the original compound.
Reduction of artemisinin to dihydroartemisinin gives rises to a chiral centre that may ultimately lead to the formation of prodrugs.
Artemisinin is a poorly soluble in oils and water so it is administered through oral, IM or rectal route.
Semi synthetic like artesunate, artemether arteether and hemisuccinate ester were produced because of poor bioavailability and limit of its effectiveness.
To stop the malarial activity, the target was a retroviral aspartyl protease which can be found in the plasmodium faliciparum parasite.
The metabolite dihydroartemisinin cleaves the endoperoxide ring inside the erythrocyte.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
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The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
2. UNIVERSITY OF AGRICULTURAL SCIENCES, RAICHUR
Discovery, Occurance , Chemical structure of Abssiscic acid
Gangadharayya S . Hiremath
PG17AGR9130
Dept of seed science &Technology
COA, Raichur
2
4. HISTORY
•In 1940s, scientists isolated a substance from
Sycamore leaves called Dormins. (Hemberg)
•In the early 1960s, Eagles and Philip Wareing
confirmed that application of a dormin to a bud
would induce dormancy
•F.T. Addicott (1963) discovered a substance stimulated
abscission of cotton fruit. He named this substance as
abscisin II
• In 1964, it became evident that the three groups had
discovered the same plant hormone.
• Later on the name was changed to abscisic acid(ABA). 4
5. CHEMICAL COMPOSITION
ABA is a 15-C Sesquiterpene compound
Composed of three isoprene residues
Cyclohexane ring with keto, one hydroxyl group, a side chain
with a terminal carboxylic group
5
6. Synonyms: 1) ABA 2) Dormin 3) Absicin II
Molecular Formula: C15H20O4
Molecular Weight: 264.32 g
Appearance: White crystals
Purity :98%
Chemical name Abscisic acid: (2-cis,4-trans)-5-(1-Hydroxy-2,6,6-
trimethyl-4-oxo-2-cyclohexen-1-yl)-3-methyl-2,4-pentadienoic acid
6
7. The orientation of carboxylic group at carbon 2 determine
the cis and trans isomers of ABA
Cis-Absscisic acid (biologically active)
Trans-Absscisic acid (biologically inactive)
Nearly all the naturally occurring ABA is in the cis form
7
8. OCCURRENCE AND DISTRIBUTION
•ABA is a ubiquitous plant hormone in vascular plants.
•In bryophytes it has been found in mosses but not in liverworts.
•A 15-C compound called lunularic acid has been found in algae and
liverworts.
• ABA is synthesized in all types of cells that contain chloroplasts or
other plastids.
•It occurs predominantly in mature green leaves.
•ABA has been detected in all major organs or living tissues from
root caps to apical buds Phloem sap, xylem sap and in nectar.
8
9. BIOSYNTHESIS
Initial stages occur in the plastids, where isopentenyl
diphosphate (IPP) is converted to the C40 xanthophyll
Zeaxanthin
Zeaxanthin is further modified to 9-cisneoxanthin, which is
cleaved by the enzyme NCED (9-cis epoxycarotenoid
dioxygenase) to form the C15 inhibitor, Xanthoxal
Xanthoxal is then converted to ABA in the cytosol
9
11. Mutants have been isolated that cause defects in the
conversion of ABA aldehyde into ABA
Flacca and Sitiens in Solanum lycopersicum
nar2a in Hordeum vulgare
Aba3 and aao3 in Arabidopsis
11
12. • Promotes stomatal closing.
•Induces bud dormancy and seed dormancy.
• Promotes desiccation tolerance in the embryo.
•Inhibits precocious germination and vivipary
•Promotes root growth and inhibits shoot
growth in stressed water condition
•Leaf Senescence
PHYSIOLOGICAL ROLE OF ABA
12