SOS response was discovered by Miroslav Radman. It's a part of DNA repair system- synthesizes enzymes required for DNA repair. Cellular response to UV damage.
Arabinose Operon is a self-regulatory sequence of genes used by material to metabolize a five-carbon sugar called arabinose when there is a deficiency of glucose in the environment.
SOS response was discovered by Miroslav Radman. It's a part of DNA repair system- synthesizes enzymes required for DNA repair. Cellular response to UV damage.
Arabinose Operon is a self-regulatory sequence of genes used by material to metabolize a five-carbon sugar called arabinose when there is a deficiency of glucose in the environment.
This presentation covers a general introduction to expression vector, its components, types, and its application. Then it covers some of the expression system with examples.
Transportable elements are DNA Sequences that move from one location in a chromosome to another within the same chromosome or into another chromosome.
These are DNA Sequences that move from one location in a chromosome to another within the same chromosome or into another chromosome.
These are DNA Sequences that move from one location in a chromosome to another within the same chromosome or into another chromosome.
These are also known as “Jumping genes”.
Bacteriophage vectors
Bacteriophage
WHY BACTERIOPHAGE AS A VECTOR?
M13 phage
Genome of m13 phage
Life cycle and dna replication of m13
CONSTRUCTION M13 AS PHAGE VECTOR
M13 MP 2 vector
M13MP7 VECTOR
Selection of recombinants
Lambda replacement vectors
LAMBDA EMBL 4 VECTOR
P1 PHAGE
GENOME OF P1 PHAGE
P1 PHAGE AS VECTOR
P1 phage vector system
This presentation covers a general introduction to expression vector, its components, types, and its application. Then it covers some of the expression system with examples.
Transportable elements are DNA Sequences that move from one location in a chromosome to another within the same chromosome or into another chromosome.
These are DNA Sequences that move from one location in a chromosome to another within the same chromosome or into another chromosome.
These are DNA Sequences that move from one location in a chromosome to another within the same chromosome or into another chromosome.
These are also known as “Jumping genes”.
Bacteriophage vectors
Bacteriophage
WHY BACTERIOPHAGE AS A VECTOR?
M13 phage
Genome of m13 phage
Life cycle and dna replication of m13
CONSTRUCTION M13 AS PHAGE VECTOR
M13 MP 2 vector
M13MP7 VECTOR
Selection of recombinants
Lambda replacement vectors
LAMBDA EMBL 4 VECTOR
P1 PHAGE
GENOME OF P1 PHAGE
P1 PHAGE AS VECTOR
P1 phage vector system
The process of movement and integration of a piece of DNA into different sites in the chromosomes called transposition.
DNA segments that carry the genes required for transposition are transposable elements or transposons, or jumping genes.
It is present in procaryotes, viruses, and eucaryotic chromosomes.
It generates new gene combinations.
It does not require extensive areas of homology between the transposon and its destination/target site.
Photosystem II captures and transfers energy.
– chlorophyll absorbs
energy from sunlight
– energized electrons
enter electron
transport chain
– water molecules are
split
– oxygen is released as
waste
– hydrogen ions are
transported across
thylakoid membrane
4.1 Chemical Energy and ATP
• Photosystem I captures energy and produces energycarrying molecules.
– chlorophyll absorbs
energy from sunlight
– energized electrons
are used to make
NADPH
– NADPH is transferred
to light-independent
reactions
4.1 Chemical Energy and ATP
• The light-dependent reactions produce ATP.
– hydrogen ions flow through a channel in the thylakoid
membrane
– ATP synthase attached to the channel makes ATP
4.1 Chemical Energy and ATP
• Light-independent
reactions occur in the
stroma and use CO2
molecules.
The second stage of photosynthesis uses energy from
the first stage to make sugars.
4.1 Chemical Energy and ATP
• A molecule of glucose is formed as it stores some of the
energy captured from sunlight.
– carbon dioxide molecules enter the Calvin Photosystem II captures and transfers energy.
– chlorophyll absorbs
energy from sunlight
– energized electrons
enter electron
transport chain
– water molecules are
split
– oxygen is released as
waste
– hydrogen ions are
transported across
thylakoid membrane
4.1 Chemical Energy and ATP
• Photosystem I captures energy and produces energycarrying molecules.
– chlorophyll absorbs
energy from sunlight
– energized electrons
are used to make
NADPH
– NADPH is transferred
to light-independent
reactions
4.1 Chemical Energy and ATP
• The light-dependent reactions produce ATP.
– hydrogen ions flow through a channel in the thylakoid
membrane
– ATP synthase attached to the channel makes ATP
4.1 Chemical Energy and ATP
• Light-independent
reactions occur in the
stroma and use CO2
molecules.
The second stage of photosynthesis uses energy from
the first stage to make sugars.
4.1 Chemical Energy and ATP
• A molecule of glucose is formed as it stores some of the
energy captured from sunlight.
– carbon dioxide molecules enter the Calvin Photosystem II captures and transfers energy.
– chlorophyll absorbs
energy from sunlight
– energized electrons
enter electron
transport chain
– water molecules are
split
– oxygen is released as
waste
– hydrogen ions are
transported across
thylakoid membrane
4.1 Chemical Energy and ATP
• Photosystem I captures energy and produces energycarrying molecules.
– chlorophyll absorbs
energy from sunlight
– energized electrons
are used to make
NADPH
– NADPH is transferred
to light-independent
reactions
4.1 Chemical Energy and ATP
• The light-dependent reactions produce ATP.
– hydrogen ions flow through a channel in the thylakoid
membrane
– ATP synthase attached to the channel makes ATP
4.1 Chemical Energy and ATP
• Light-independent
reactions occur in the
stroma and use CO2
molecules.
The second stage of photosynthesis uses energy frvf
Replication:
DNA replication is the biological process of producing two identical copies of DNA from the original/parentral DNA molecule.
This process occurs in all living organism.
Basis for biological inheritance
DNA Replication Is Semiconservative
Replication Begins at an Origin and Usually Proceeds Bidirectionally
DNA Synthesis Proceeds in a 5’-3’ Direction and Is semidiscontinuous
DNA replication is an important process which takes place in every organisms, be it prokaryotic or eukaryotic. The DNA replication process produces two identical copies of daughter DNA molecules using the existing DNA molecule as template. Each daughter DNA molecule inherits one strand from the parent cell and the other strand is newly synthesized. This is known as semiconservative mode of replication, demonstrated by Meselson and Stahl.
DNA replication, repair and recombination NotesYi Fan Chen
DNA, replication, repair and recombination Notes based on Molecular biology of the cell. Biology Elite: biologyelite.weebly.com, please use together with the presentation
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
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 .
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
2. TRANSPOSITION
• The transpositions is the movement of generic element
called transposons or transposable element between
plasmids and genomes.
• TRANSPOSONS : A DNA sequence able to insert itself (or a
copy of itself) at a new location in the genome without
having any sequence relationship with the target locus
3. MECHANISMS OF
TRANSPOSITION
• The insertion of a transposon into a
new site
• It consist of making staggered breaks in
the target DNA, joining the transposon
to the single stranded ends, and filling
in the gaps.
• The generation and filling of the
staggered ends explains the
occurrence of the direct repeats of
target DNA at the site of insertion .
The direct repeats of target
DNA flanking a transposon are
generated by the introduction
of staggered cuts whose
protruding ends are linked to
the transposon.
4. •The stagger between the cuts on the two strands
determines the length of the direct repeats; thus the
target repeat characteristic of each transposon
reflect the geometry of the enzyme involved in
cutting target DNA.
•The use of staggered ends is common to most
means of transposition, but we can distinguish two
major types of mechanisms by which a transposon
moves
Replicative transposition
Non replicative transposition
5. REPLICATIVE
TRANSPOSITION
• In replicative transposition, the
element is duplicated during the
reaction so that the transposing
entity is a copy of the original
element.
• The transposon is copied as part
of its movement.
• One copy remains at the new site,
whereas the other inserts at the
new site.
Replicative transposition creates
a copy of the transposon, which
inserts at a recipient site. The
donor site remains unchanged, so
both donor and recipient have a
copy of the transposon.
6. • Thus transposition is accompanied by an increase in the
number of copies of the transposons.
• Replicative transposition involves two types of enzymatic
activity:
• Transposase
• Resolvase
• A transposase act on the end of the original transposons
• Resolvase act on the duplicated copies
• While one group of transposons moves only by replicative
transpositions, true replicative transposition is relatively rare
among transposons in general
7. NON REPLICATIVE
TRANSPOSITION
• In non replicative transposition the
transposing element moves as a
physical entity directly from one
site to another and is conserved.
• The insertion sequences and
composite transposons (Tn) Tn10
and Tn5 use the mechanism which
involves the release of the
transposon from the flanking donor
Non replicative transposition
allows a transposon to
move as a physical entity
from a donor to a recipient
site. This leaves a break at
the donor site, which is
lethal unless it can be
repaired.
8. •This mechanism is often referred to as cut and paste,
requires only a transposase.
•Another mechanism utilizes the connection of donor and
target DNA sequence and shares some steps with
replicative transposition .
•Both the mechanism o non replicative transposition
cause the element to be insert at the target site and lost
from the donor site.
•The donor DNA requires that the host repair system
recognize the double strand break and repair it.
9. • Some bacterial transposons use only one type of pathway for
transposition, whereas other may e to use multiple pathways
• The element IS1 and IS903 use both replicative and non replicative
pathways, and the ability of phage Mu to turn to either type of
pathway from a common intermediate have been well characterized
• The same basic type of reaction are involved in all classes of
transposition events
• The end of the transposon are disconnected from the donor DNA y
cleavage reaction that generate 3’-OH ends
• The exposed ends are then joined to the target DNA by transfer
reaction, involving transesterification in which the 3’-OH end directly
attacks the target DNA
10. • These reaction takes place within a nucleoprotein complex that
consist the necessary enzymes and both ends of the transposition
• Transposon differ as to whether the target DNA recognized before or
after the cleavage of the transposons itself, and whether one or both
stands at the end of the transposon are cleaved prior to integrate
• The choice of target site is in effect made by the transposase,
sometimes in conjunction with accessory protein
• In some case, the target is chosen virtually for a consensus of
sequenceor for some other feature in the target
• The feature can take the form of a structure in DNA, such as bent
DNA, or a protein-DNA complex
• In later case, the transposons to insert promoters (such as Ty1 or
Ty3,which select pol III promoters in yeast), inactive region of the
chromosome, or replicative DNA
11. REPLICATION TRANSPOSITION PROCEEDS
THROUGH A COINTEGRATE
• The 3’ end of the strand transfer complex are used as primer for
replication.
• This generates the structure called a cointegrate, which represents
the fusion of two original molecules.
• The cointegrate has two copies of transposons.
• The crossover is formed by the transposase, it conversion into the
cointegrate requires host replication function.
12. • The recombination between the two copies of the transposon
release two individual replicons, each of which has a copy of the
transposon.
• One replicon is original donor replicon and other is the target
replicon that has gained a transposon flanked by short direct
repeats of the host target sequence.
• This recombination reaction is called as resolution; the enzyme
activity responsible is called the resolvase.
• This generation is involved in phage Mu. The process starts with
the formation of the strand transfer complex.
• The donor and target strand are ligated so that each end of the
transposon sequence is joined to one of the protruding single
strand generated at the target site.
13. • The strand transfer complex generates a crossover-shaped structure
held together at the duplex transposon. The fate of the crossover
structure determines the mode of transposition.
PRINCIPLE:
The principle of replicative transposition is that replication
through the transposon duplicates it, which create copies at both the
target and donor sites. The product is a cointegrates
The crossover structure contains a single stranded region at each end
of the staggered ends . These regions are pseudoreplicative fork that
provide a templet for DNA synthesis.
14. •If replication continues from both the
pseudoreplicative fork, it will proceeds through
the transposon, separating it strand and
terminating at its end.
•Replication is accomplished by host-coded
function. At this juncture, the structure has
become a cointegrate, possessing the direct
repeats of the transposon at the junction
between the replicon.
15.
16. NON REPLICATIVE PROCEEDS BY
BREAKAGE AND REUNION
• The crossover structure also used in non replicative transposition.
PRINCIPLE:
The principle of non replicative transposition by this mechanism is that
the breakage and the reunion reaction allows the target to be
reconstructed with the insertion of the transposon; the donor remain
broken. No cointegrate is formed
17.
18. • Once the unbroken donor strand have been nicked, the target strand
on either side of the transposon can be ligated. The single- stranded
region generated by staggered cut must be filled in by repair
synthesis.
• The product of the reaction is the target replicon in which the
transposon has been inserted between repeats of the sequence
created by the original single-strand nick.
• The donor replicon has the double-strand break across the site where
the transposon was originally located.
• Non replicative transposition can also occurs in the alternative
pathway in which nick are made in target DNA, but a double strand
break is made on either side of the transposon.
• This “cut and paste” pathway is used by Tn10 and many eukaryotes
19. • A simple experiment to prove that Tn10 transposes non replicative
made use of an artificially constructed heteroduplex of Tn10 that
contain single-base mismatches.
• If transposition involves replication, the transposon at the new site will
contain information from only one of the parent Tn stand .
• If ,however, transposition takes place by physical movement of the
existing transposon ,the mismatch will be conserved at the new site.
EXPERIMENT ON TN10
20.
21. TN 5 TRANSPOSON:
• Tn 5 also is a non-replicative transposition.
• It have a interesting cleavage reaction that separate the transposons
from the flanking sequence .
• Frist one DNA strand is nicked. The OH end that is released then
attacks the other strand DNA
• This release the flanking sequence and joins the two strand of the
transposonin a hairpin.
• An activated water molecule that attack the hairpin to generate free
end for each strand of the transposon
22.
23. • In next step, the cleaved donor DNA is released, and the transposon is
joined to the nicked end at the target site.
• The transposon and the target site constrained in the proteinaceous
structure created by the transposase.
• The double-strand cleavage at each end of the transposon precludes any
replicative-type transposition and forced the reaction to proceed by non-
replicate transposition, thus gives same out comes.
• But with the individual cleavage and joining steps acquiring in a different
order.
• The Tn 5 and Tn 10 transposases both function as dimer.
• Each subunit in the dimer has an active site that successively catalyze the
double strand breakage of the two strand at one end transposon, and they
catalase staggered cleavage of the target site.
• Each end of the transposon is located in the active site of one subunit.
24. •One end of the subunit also contacts the other
end of the transposon. This controls the
geometry of the transposition reaction.
•Each of the active site will cleave one strand of
the target strand. It is the geometry of the
complex that determines the distance between
these site on the two target strands.