Recombinant DNA technology involves cutting and joining DNA from different sources to produce novel DNA molecules. Some key developments included Watson and Crick discovering the DNA structure in 1953, and Cohen and Boyer producing the first plasmid vector capable of replication in bacteria in 1973. The goals of rDNA technology are to isolate, characterize, alter, and return genes to living cells to understand diseases and improve organisms. Common techniques used include PCR, gel electrophoresis, cloning libraries, and restriction enzyme mapping. Vectors like plasmids, lambda phage, cosmids, and BACs are used to clone and replicate recombinant DNA. Applications include producing medicines like insulin, developing pest-resistant crops, and gene therapy.
Recombinant DNA (rDNA) molecules are DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome.
Recombinant DNA (rDNA) molecules are DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome.
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.
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 .
(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.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
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.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
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.
Comparative structure of adrenal gland in vertebrates
biotechnology
1. Recombinant DNA technology
DNA molecules that are extracted from different
sources and chemically joined together; for example
DNA comprising ananimal gene may be recombined
with DNA from a bacterium
2. Discovery of recombinant DNA
technology
Discovery of DNA structure Watson & Crick in 1953
Isolation of DNA ligase in 1967
Isolation of REase in 1970
Paul Berg generated rDNA technology in 1972
Cohen & Boyer in 1973 produced first plasmid vector
capable of being replicated within a bacterial host
3. Goals of recombinant DNA technology
• To isolate and characterize a gene
• To make desired alterations in one or more isolated genes
• To return altered genes to living cells
• Artificially synthesize new gene
• Alternating the genome of an organism
• Understanding the hereditary diseases and their cure
• Improving human genome
4. Procedure of making rDNA
Isolating of DNA
Cutting of DNA
Joining of DNA
Amplifying of DNA
6. Cutting of DNA
• DNA can be cut into large fragments by mechanical
shearing.
• Restriction enzymes are the scissors of molecular
genetics.
7. Restriction enzyme
• A special class of sequence-specific enzyme
• Found in bacteria
• Site-specific-cleave DNA molecules only at
specific nucleotide sequence
• REases recognize DNA base sequence that
are palindrome
• REase make staggered cuts with
complementary base sequences for easy
circulization
9. Amplifying the recombinant DNA
• Transforming the recombinant DNA into a bacterial host strain.
• The cells are treated with CaCl2
• DNA is added
• Cells are heat shocked at 42 C
• DNA goes into cell by a somewhat unknown mechanism.
• Once in a cell, the recombinant DNA will be replicated.
• When the cell divides, the replicated recombinant molecules go to both
daughter cells which themselves will divide later. Thus, the DNA is
amplified
11. Enzymes usedin recombinant DNA technology
• Bind to DNA molecules
DNA ligase
• Cleaves DNA at specific sites
Type II restriction endonuclease
• Make a DNA copy of RNA molecule
Reverse transcriptase
• Fill single stranded gapes of DNA duplex
DNA polymerase I
• Adds a phosephate to the 5'-OH end of a polynucleotide
Polynycleotide Kinase
• Adds homopolymer tails to the 3'-OH ends
Terminal transferase
• Removes nucleotide residues from the 3' ends
Exonuclease III
• removes nucleotides from the 5' ends
Bacteriophage {lamda} exonuclease
• Removes terminal phosphates
Alkaline phosphatase
12. Vectors used in rDNA technology
• A vector is an area of DNA that can join another DNA
part without losing the limit for self-replication
• Should be capable of replicating in host cell
• Should have convenient RE sites for inserting DNA of
interest
• Should have a selectable marker to indicate which
host cells received recombinant DNA molecule
• Should be small and easy to isolate
13. Vectors used in rDNA technology
vectors
BACS
YACS
express
ion
cosmid
Lamda
phage
plasmid
14. Plasmid vector
• Plasmids are small, circular DNA molecules
that are separate from the rest of the
chromosome.
• They replicate independently of the
bacterial chromosome.
• Useful for cloning DNA inserts less that 20
kb (kilobase pairs).
• Inserts larger than 20 kb are lost easily in
the bacterial cell.
15. Lamda phage vector
• Lamda phage vectors are recombinant
infections, containing the phage chromosome
in addition to embedded "outside" DNA.
• All in all, phage vectors can convey bigger DNA
groupings than plasmid vectors.
16. Cosmid vector
• Cosmids are hybrids of
phages and plasmids that
can carry DNA fragments
up to 45 kb.
• They can replicate like
plasmids but can be
packaged like phage
lambda
17. Expression vectors
• Expression vectors are
vectors that carry host
signals that facilitate the
transcription and
translation of an inserted
gene.
• They are very useful for
expressing eukaryotic
genes in bacteria.
18. Yeast artificial chromosomes (YACS)
• Yeast artificial chromosomes (YACS) are yeast
vectors that have been engineered to contain a
centromere, telomere, origin of replication,
and a selectable marker.
• They can carry up to 1,000 kb of DNA.
• they are useful for cloning eukaryotic genes
that contain introns.
19. Bacterial artificial chromosomes (BACS
• Bacterial artificial
chromosomes (BACS) are
bacterial plasmids derived
from the F plasmid. They
are capable of carrying up
to 300 kb of DNA.
20. Techniques used in rDNA technology
• Gel electrophoresis
• Cloning libraries
• Restriction enzyme mapping
• PCR
• Nucleic Acid Hybridization
• DNA Microarrays
21. Gel electrophoresis
Gel electrophoresis – DNA fragments of different
sizes can be separated by an electrical field applied
to a “gel”.
The negatively charged DNA migrates away from the
negative electrode and to the positive electrode.
The smaller the fragment the faster it migrates.
22. Cloning libraries
• Libraries are collection of DNA clones in a certain
vector.
• The goal is to have each gene represented in the
library at least once.
• Genomic - made from RE DNA fragments of total
genomic DNA
• cDNA (complementary DNA) – made from DNA
synthesized from mRNA
23. PCR
• Allows the isolation of a specific segment of DNA
from a small DNA (or cell sample) using DNA
primers at the ends of the segment of interest.
24. Restriction enzyme mapping
• Frequently it is important to have a restriction enzyme site
map of a cloned gene for further manipulations of the gene.
• This is accomplished by digestion of the gene singly with
several enzymes and then in combinations.
• The fragments are subjected to gel electrophoresis to
separate the fragments by size and the sites are deduced
based on the sizes of the fragments.
25. Nucleic Acid Hybridization
• A Southern allows the detection of a gene of interest
by probing DNA fragments that have been separated
by electrophoresis with a “labeled” probe.
• Northern Blot (probe RNA on a gel with a DNA
probe)
• Western Blot (probe proteins on a gel with an
antibody)
26. DNA Microarrays
• vast majority of the protein-
encoding qualities onto a
microarray chip, utilizing
innovation in light of the DNA
silicon chip industry.
• The chip can be utilized to
hybridize to cell RNA, and
measure the statement rates of a
substantial number of qualities
in a cell.
27. Applications of rDNA technology
• Agriculture: growing crops of your choice (GM food),
pesticide resistant crops, fruits with attractive colors, all
being grown in artificial conditions
• Pharmacology: artificial insulin production, drug delivery to
target sites
• Medicine: gene therapy, antiviral therapy, vaccination,
synthesizing clotting factors
• Other uses:fluorescent fishes, glowing plants etc
