The document summarizes the Ames test, which is used to assess the mutagenic potential of chemical compounds. It uses Salmonella typhimurium bacteria as a test organism to detect mutations caused by exposure to test chemicals. If the test chemical causes more reversed his+ bacteria compared to unexposed controls, then it is considered mutagenic. The Ames test is widely used in pharmaceutical, cosmetic, and food industries to screen for potentially carcinogenic chemicals. Though not 100% accurate, it is a simple, inexpensive, and effective way to identify many mutagenic and carcinogenic compounds.
A knockout mouse is a mouse in which a specific gene has been inactivated or“knocked out” by replacing it or disrupting it with an artificial piece of DNA.
The loss of gene activity often causes changes in a mouse's phenotype and thus provides valuable information on the function of the gene.
A knockout mouse is a mouse in which a specific gene has been inactivated or“knocked out” by replacing it or disrupting it with an artificial piece of DNA.
The loss of gene activity often causes changes in a mouse's phenotype and thus provides valuable information on the function of the gene.
Presentation on nested pcr . contain types of pcr, protocol of nested pcr, advantages of nested pcr, disadvantages of nested pcr, application of nested pcr ,pictorial representation of pcr.
Sanger sequencing is one of the DNA sequencing methods used to identify and determine the sequence (Nucleotide) of DNA .This is an enzymatic method of sequencing developed by Fred Sanger.
In this slide contains principle, types, methods and application of Western Blotting Technique.
Presented by: T.NIRANJAN REDDY (Department of pharmacology).
RIPER, anantapur
Presentation on nested pcr . contain types of pcr, protocol of nested pcr, advantages of nested pcr, disadvantages of nested pcr, application of nested pcr ,pictorial representation of pcr.
Sanger sequencing is one of the DNA sequencing methods used to identify and determine the sequence (Nucleotide) of DNA .This is an enzymatic method of sequencing developed by Fred Sanger.
In this slide contains principle, types, methods and application of Western Blotting Technique.
Presented by: T.NIRANJAN REDDY (Department of pharmacology).
RIPER, anantapur
This presentation includes the basic knowledge of Ames Test with a lot of understandable knowledge. I hope all the finders liked it and also remember me in your precious Dua. Thank You!
Alternative to animal toxicit testing.pptxANANYAPANDEY71
Alternative to animal toxicity studies
pharmacological and toxicological studies
hetcam test
pyrogen test
3R
Refinment,Reduction &Replacement
In-Silico methods
CADD, QSAR
genotoxicity describes the property of chemical agents that damages the genetic information within a cell causing mutations, which may lead to cancer. While genotoxicity is often confused with mutagenicity, all mutagens are genotoxic, whereas not all genotoxic substances are mutagenic
Antibiotic Susceptibility Pattern of Pyogenic Bacterial Isolates in Sputum.IOSR Journals
Drugs Have Been Used For The Treatment Of Infectious Diseases Since 17th Century , However
Chemotherapy As A Science Has Began With Paul Ehrlich In The First Decade Of 20th Century . Paul Ehrlich
(1854-1915) Was One Of The Earliest Pioneers In The Field Of Antimicrobial Chemotherapy .1Ehrlich
Formulated The Principles Of “Selective Toxicity” ,I.E; Selective Inhibition Of The Growth Of Microorganisms
Without Damage To The Host.2 Resistance Has Been Documented Not Only Against Antibiotics Of
Natural And Semi- Synthetic Origin , But Also Against Purely Synthetic Compounds (Flouroquinolone) Or
Those Which Do Not Even Enter The Cells (Vancomycin) .3 However , The Euphoria Over The Potential
Conquest Of Infectious Diseases Was Short-Lived .Almost As Soon As Antibacterial Drugs Were Deployed ,
Bacteria Responded By Manifesting Various Forms Of Resistance.4 Considered As “Wonder Drugs”
Antibiotics Are Often Prescribed Inappropriately And Inadequately And Have Thus Became One Of The
Highly Abused Agents.5
Antibiotic Resistance form food of animal origint- Debatable issueAsima Zehra
Contribution to the development of antibiotic resistance is multifactorial wherein human medicine plays a major role and food of animal origin are least to bother.
mutagen is a physical or chemical agent that permanently changes genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level. As many mutations can cause cancer in animals, such mutagens can therefore be carcinogens, although not all necessarily are. All mutagens have characteristic mutational signatures with some chemicals becoming mutagenic through cellular processes.
The process of DNA becoming modified is called mutagenesis. Not all mutations are caused by mutagens: so-called "spontaneous mutations" occur due to spontaneous hydrolysis, errors in DNA replication, repair and recombination.
Discovery
The first mutagens to be identified were carcinogens, substances that were shown to be linked to cancer. Tumors were described more than 2,000 years before the discovery of chromosomes and DNA; in 500 B.C., the Greek physician Hippocrates named tumors resembling a crab karkinos (from which the word "cancer" is derived via Latin), meaning crab.[1] In 1567, Swiss physician Paracelsus suggested that an unidentified substance in mined ore (identified as radon gas in modern times) caused a wasting disease in miners,[2] and in England, in 1761, John Hill made the first direct link of cancer to chemical substances by noting that excessive use of snuff may cause nasal cancer.[3] In 1775, Sir Percivall Pott wrote a paper on the high incidence of scrotal cancer in chimney sweeps, and suggested chimney soot as the cause of scrotal cancer.[4] In 1915, Yamagawa and Ichikawa showed that repeated application of coal tar to rabbit's ears produced malignant cancer.[5] Subsequently, in the 1930s the carcinogen component in coal tar was identified as a polyaromatic hydrocarbon (PAH), benzo[a]pyrene.
Polyaromatic hydrocarbons are also present in soot, which was suggested to be a causative agent of cancer over 150 years earlier.
Similar to Detection of mutation by ames test (20)
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 .
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
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.
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.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
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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.
(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.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
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4. WHAT IS AMES TEST ?
Ames test is performed for testing the mutagenic property
of a chemical using bacteria as a test organism.
It is a biological assay to assess the mutagenic potential of
chemical compounds.
DISCOVERY
Ames test was discovered by Bruce
Ames and his group in 1974 at
University of California , Berkeley.
5. TEST ORGANISM
OF AMESTEST
His ⁻ Salmonella
typhimurium is
used.
These mutants
are auxotrophic.
Salmonella typhimurium
6. It is a physical or
chemical agent that
changes DNA of an
organism and
increases the
frequency of
mutations.
Most mutagens are
carcinogens.
WHAT IS MUTAGEN ?
12. S.typhimurium is a prokaryote,therefore it is
not perfect model for human.
Drugs that contain the nitrate moiety,
sometimes come back +ve for AmesTest
when they are indeed safe.
It does not give 100% accuracy.
13. AmesTest is widely used by pharmaceutical
industry.
15. AmesTest is also widely used in Food
Processed Industries.
16. It is easy to understand
Less expensive
Less time taking
Easy to handle
Its is simple
17. Though Ames test is not 100% accurate but
still it helps us to get rid of 100s of mutagenic
compounds which can cause dreadful disease
like cancer.
By using many new emerging techniques
efficiency of Ames test can be improved.
18. 1. N.F. Cariello, W.W. Piegorsch,The Ames test: the two-
foldrule revisited, Mutant. Res. 369 (1996) 23–31.
2. B.N. Ames,W.E. Durston, E.Yamasaki, F.D.
Lee,Carcinogens are mutagens: a simple test system
combiningliver homogenates for activation and bacteria for
detection,Proc. Natl. Acad. Sci. U.S.A. 70 (1973) 2281–2285.
3. A. Araki,T. Noguchi, F. Kato,T. Matsushima, Improved
method for mutagenicity testing of gaseous compounds by
using a gas sampling bag, Mutat. Res. 307 (1994) 335–344.
