The document summarizes regulation of gene expression through the lac operon in E. coli. It describes how Francois Jacob and Jacques Monod discovered the lac operon in the 1960s and were awarded the Nobel Prize. The lac operon is a cluster of genes whose expression is regulated by an operator and repressor protein. In the absence of lactose, the repressor binds the operator to prevent transcription. When lactose is present, it binds to the repressor and causes derepression, allowing transcription of genes encoding beta-galactosidase, lactose permease, and transacetylase which break down lactose. Positive control involves cAMP and CAP activating transcription when glucose levels are low.
INTRODUCTION
Definition
history
DIFFERENT PHASE
G0 PHASE
INTERPHASE
M PHASE
CHECKPOINT
HOW DOES IT WORK
Inhibitors
Mechanism of action
Function
CONCLUSION
references
INTRODUCTION
Definition
history
DIFFERENT PHASE
G0 PHASE
INTERPHASE
M PHASE
CHECKPOINT
HOW DOES IT WORK
Inhibitors
Mechanism of action
Function
CONCLUSION
references
The lac operon- The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria. This operon contains genes coding for proteins in charge of transporting lactose into the cytosol and digesting it into glucose.This glucose is then used to make energy.
MAPK Signaling pathway (Mitogen-activated protein kinase), how the pathway helps in regulation of mitosis, It's activation and inactivation inside the cell, roles of MAPK pathway in cancerous cell, different classes of MAP kinase in human
A cell cycle is a series of events that takes place in a cell as it grows and divides. The process has to be correct and regulated. This slide illustrated Cell cycle and its regulation. Check the slides to know more.
This is the first one of a series of lectures about the "Cell". I am here introducing some basic principles about the cell structure, types, histology and biochemistry
1.Receptors Link to other Enzymatic Activity.
2.Pathway of Intracellular Signal Transduction.
3.The Cyclic AMP pathway 4.Cyclic GMP pathway
5.Phospholipids and Ca2+
6.The PI3-Kinase /Akt and mTOR pathways.
7.MAP Kinase Pathway.
The forth lecture about the "Cell".
Here, I am discussing the several signaling pathways.....It is highly dependent on the 3rd lecture; Receptors.
Enjoy :)
The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria..............................................learn more in slides
The lac operon- The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria. This operon contains genes coding for proteins in charge of transporting lactose into the cytosol and digesting it into glucose.This glucose is then used to make energy.
MAPK Signaling pathway (Mitogen-activated protein kinase), how the pathway helps in regulation of mitosis, It's activation and inactivation inside the cell, roles of MAPK pathway in cancerous cell, different classes of MAP kinase in human
A cell cycle is a series of events that takes place in a cell as it grows and divides. The process has to be correct and regulated. This slide illustrated Cell cycle and its regulation. Check the slides to know more.
This is the first one of a series of lectures about the "Cell". I am here introducing some basic principles about the cell structure, types, histology and biochemistry
1.Receptors Link to other Enzymatic Activity.
2.Pathway of Intracellular Signal Transduction.
3.The Cyclic AMP pathway 4.Cyclic GMP pathway
5.Phospholipids and Ca2+
6.The PI3-Kinase /Akt and mTOR pathways.
7.MAP Kinase Pathway.
The forth lecture about the "Cell".
Here, I am discussing the several signaling pathways.....It is highly dependent on the 3rd lecture; Receptors.
Enjoy :)
The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria..............................................learn more in slides
Fungi have both positive ad negative roles in our daily life. So they are our friends as well as foes (enemy).
They are described as below.
Beneficial Roles or Useful Activities.
i) Fungi are used as food. e.g. Mushrooms and Morels.
ii) Fungi are used in laboratory.
a) Baking Yeast (S. cerevisae)
b) Several alcoholic beverages such as wine, whiskey, beer, rum all are prepared by fermentation activity of sugar solution by wine yeast. (S. ellipsoidens) c) Some fungi are used in production of enzymes like amylase, pectimase
iii) Some fungi are used in production of several antibiotics and antibiotics and other useful medicine like penicillin, streptomycin, ergotine and ephedrine respectively.
iv) Several fungi are used in commercial production of different organic products like citric acid, fumaric, lactic and oxalic acid.
v) Fungi in agriculture:
a) Being saprophytes they decompose the organic matter and enhance the fertility of the soil.
b) Some fungi develop symbiotic relation with roots of higher plant like Pinus and help them in absorption of nutrients. Such fungi are known as mycorrhiza.
vi) Some fungi are used to produce hormone like Gibberellin.
Harmful Activities:
i) Food spoilage (destruction) caused by fungi like mucor and yeast.
ii) Some yeasts causes huge loss in silk industry to attack silk worms and kill the same.
iii) Several types of plant diseases caused by (different types of fungi) species of Nematospra they attack tomatoes, cotton and bean plants.
Similar disease like causal organisms
a. Stem rust of wheat – Pucvinia graministice
b. Early blight of potato – Alternaria solani
c. Late blight of potato – Phytiphtoria infestans
d. White rust of crucifer – Albugo candida
iv) Some fungi (Cryptococcus neoformans) may cause human disease like meningitis and brain tumor.
- Torula and other yeasts produce small nodules on the skin and lesions in the viscera and bones of man.
v) Some fungi are concerned with destruction of substances like attacks textile materials, paper, leather goods, rubber even optical instruments.
vi) Some fungi are not edible mushroom like different species Amanita.
This question has also been asked frequently in HSEB Board Exam as, Explain the economic importance of fungi, Fungi are our friends as well as enemies, Explain. etc.
Regulation of gene expression in prokaryotes and virusesNOOR ARSHIA
Regulation of gene expression in prokaryotes and viruses includes gene expression mechanism of prokaryotes such as lac operon ,trp operon, feedback inhibition, types of temporal response, positive and negative gene regulation. It also includes mechanisms such as reverse transcriptase in viruses.
This is my first presentation share in this platform. Hope this is helpful for you! Here, I have tried to explain MECHANISM OF LAC OPERON in E.Coli in informative and crisp manner with simple language and few images.
Explain the “life” of a secreted protein molecule - trace the pathwa.pdfArrowdeepak
Explain the “life” of a secreted protein molecule - trace the pathway in a cell by which a secreted
protein, such as an antibody, would be produced in an animal cell, starting in the nucleus.
Solution
Cells secrete proteins for their own cytosol or for release into surrounding extracellular fluid.
These secretions may include various hormones, digestive enzymes, antibodies, mucus etc.
The transcription process (conversion of DNA to mRNA) occurs inside the nucleus. This newly
formed mRNA is translated into proteins in the cytosol at cellular structures called ribosomes.the
ribosome remains in the cytosol if the protein has to be used within the cell, whereas if it is
destined for secretion outside the cell, the signal sequence (first few amino acids) is synthesized
on the ribosome and then the ribosome docks at the rough endoplasmic reticulum (RER) for
completion of protein synthesis. Proteins enter and cross endoplasmic recticulum (ER)
membrane co-translationally (i.e., they cross ER during synthesis of polypeptide). In the lumen
of ER, proteins undergo glycosylation and molecular chaperones aid in the process of protein
folding. Misfolded proteins are retrotranslocated to the cytosol, where they are degraded by a
proteasome action.
The vesicles with correctly folded proteins then enter the golgi appratus where further
posttranslational modifications occur including cleavage and functionalization. When the protein
moves through the entire Golgi apparatus, it buds off as secretion vesicles. Now, with the help of
cell\'s cytoskeleton, it moves towards the edge of the cell and attaches itself to the membrane.
Eventually, vesicle fuses with the cell membrane releasing its contents out of the cell through
the process of exocytosis.
This secretion pathway is followed for all protein molecules including antibodies..
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
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Monitor common gases, weather parameters, particulates.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
1. Regulation of Gene ExpressionRegulation of Gene Expression
By – Ajay Kumar
M.Sc. -2
Paper- 1
2. Discovery
Francois Jacob and Jacques
Monod (Pasteur Institute,
Paris, France)
• Studied the organization and
control of the lac operon in
E. coli.
• Awarded the Nobel Prize in
Physiology and Medicine
1965.
Francois Jacob
Jacques Monod
3. What is Operon ???
Cluster of genes in which expression is regulated by operator-
repressor protein interactions. plus the operator region itself and
the promoter.
• Contents of an operon:
Promoter
Repressor
Operator (controlling site)
Coding sequences
5. Regulated genes
Control cell growth and cell division.
Expression is regulated by the needs of the cell and or
organism.
Constitutive genes
Continuously expressed.
House keeping genes such as those required for protein
synthesis and glucose metabolism.
6. -galactosidase (lacZ)
•Breaks lactose into glucose + galactose.
•Converts lactose to the allolactose, regulates lac operon.
•Lactose permease (lacY)
•Transports lactose across cytoplasmic membrane.
•Transacetylase (lacA)
•transfers an acetyl group from acetyl-CoA to -galactosides.
Structural gene
10. Positive control in the lac operon:
• When glucose and lactose are present, E. coli preferentially uses glucose due to
low levels of active CAP (low cAMP).
• Catabolite activator protein (CAP) binds cAMP, activates, and binds to a CAP
recognition site upstream of the promoter (cAMP is greatly reduced in presence
of glucose).
• CAP changes the conformation of DNA and facilitates binding of RNA
polymerase and transcription.
• Adding cAMP to cells restore transcription of the lac operon even when glucose
is still present.
11.
12. Bibliography & webliography
I-Genetics A Molecular approach third edition
By- Peter J. Russell
Genetics (from Genes to Genomes)
By- Michael Goldberg,Leory Hood
www.cat.cc.md.us/courses/bio141/lecguide/
unit4/genetics/protsyn/regulation/
