Pseudomonas aeruginosa establishes itself in the lungs of cystic fibrosis patients and uses quorum sensing to coordinate biofilm formation. Quorum sensing involves the production and detection of signaling molecules called homoserine lactones, which trigger biofilm formation and virulence factor production above a threshold concentration. Detecting these signaling molecules can indicate the presence of P. aeruginosa biofilms early on. Inhibiting quorum sensing is a promising approach for novel cystic fibrosis therapies, as it may prevent biofilm formation and make bacteria more susceptible to antibiotics.
This presentation elaborates on the process through which bacteria communicate with each other using signalling molecules which they can produce and receive.
This presentation elaborates on the process through which bacteria communicate with each other using signalling molecules which they can produce and receive.
This is technique used widely for protein separation from a mixture and is very easy and less costly method. Slides cover all essential points about EMSA and it is quite interesting to know that how it detect and separate different proteins and their mobility shift assay.
Arabinose operon and their regulation and arac VijiMahesh1
arabinose operon and their detalied explanation about the operon conceptt and their regulation both positive and negative and the detailed explanation of the promoter ,operator,inducer,structural gene,arac protein
Bacterial processes such as biofilm formation, virulence factor secretion, bioluminescence, antibiotic production, sporulation, and competence for DNA uptake are often critical for survival
However, these behaviors are seemingly futile if performed by a single bacterium acting alone. Yet, we know that bacteria perform these tasks effectively. How do bacteria manage?
We now understand that, through a process called quorum sensing, bacteria synchronously control gene expression in response to changes in cell density and species complexity.
It includes the information related to a bioinformatics tool BLAST (Basic Local Alignment Search Tool), BLAST is in-silico hybridisation to find regions of similarity between biological sequences. The program compares nucleotide or protein sequences to sequence databases and calculates the statistical significance. This presentation too contains the input - output format, Blast process and its types .
A brief introduction to two techniques used to study protein interactions: Yeast two hybrid (Y2H) system and Chromatin immunoprecipitation(ChIP)
I hope it helps and please comment if I've made any mistakes.
This is technique used widely for protein separation from a mixture and is very easy and less costly method. Slides cover all essential points about EMSA and it is quite interesting to know that how it detect and separate different proteins and their mobility shift assay.
Arabinose operon and their regulation and arac VijiMahesh1
arabinose operon and their detalied explanation about the operon conceptt and their regulation both positive and negative and the detailed explanation of the promoter ,operator,inducer,structural gene,arac protein
Bacterial processes such as biofilm formation, virulence factor secretion, bioluminescence, antibiotic production, sporulation, and competence for DNA uptake are often critical for survival
However, these behaviors are seemingly futile if performed by a single bacterium acting alone. Yet, we know that bacteria perform these tasks effectively. How do bacteria manage?
We now understand that, through a process called quorum sensing, bacteria synchronously control gene expression in response to changes in cell density and species complexity.
It includes the information related to a bioinformatics tool BLAST (Basic Local Alignment Search Tool), BLAST is in-silico hybridisation to find regions of similarity between biological sequences. The program compares nucleotide or protein sequences to sequence databases and calculates the statistical significance. This presentation too contains the input - output format, Blast process and its types .
A brief introduction to two techniques used to study protein interactions: Yeast two hybrid (Y2H) system and Chromatin immunoprecipitation(ChIP)
I hope it helps and please comment if I've made any mistakes.
This presentation talks about the molecular basis of Quorum sensing in the virulence of bacterial pathogens and the potential of quorum sensing to serve as drug target.
Abdominal Tuberculosis – How Far are Our Diagnostics Illuminating?Apollo Hospitals
Tuberculosis can involve any part of the gastrointestinal tract from mouth to anus, the peritroneum, pancreas and the hepatobiliary system. Gastrointestinal tuberculosis mimics many clinical conditions and only a high degree of suspicion can help in the diagnosis otherwise there are chances of missing it leading to high morbidity and mortality. Various methods of diagnosis are available but which one is the right test for a particular patient needs to be ascertained. Culture remains the gold standard method of diagnosis. Fast track cultures like MGIT/M Bact Alert 3 D can give faster results with in few days to few weeks. Molecular tests are fastest and can be used as a supplementary test. Nested PCR can give results with in few hours.
Similar to Quorum Sensing in detection of Pseudomonas aeuroginosa biofilms in cystic fibrosis (20)
The presentation includes information about bacteria Bacillus anthracis like its structure, characters, infection, life cycle, pathogenicity and diseases caused by it which is Anthrax. It includes information about types of anthrax, symptoms, diagnosis, treatment, and prevention.
Richard's aventures in two entangled wonderlandsRichard Gill
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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 .
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
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Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
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Quorum Sensing in detection of Pseudomonas aeuroginosa biofilms in cystic fibrosis
1. SONAL RAWAT
A0989216038Sonal Rawat
BSc(H) Microbiology
Sem-6 Section- B
A0989216038
Quorum Sensing an approach in
detection of Pseudomonas aeruginosa
biofilms in cystic fibrosis
2. Cystic fibrosis and Pseudomonas
aeruginosa
• Cystic fibrosis is a hereditary disorder that affects the exocrine glands
like sweat glands and mucosal glands of patients.
• The CF gene encodes a protein known as cystic fibrosis trans
membrane conductance regulator (CFTR). Mutation of this gene
makes the CFTR protein dysfunctional which acts as channel for large
mucus production.
• These mucoid secretions clog airways and reduces mucocilliary
clearance of inhaled microbes and leads to the formation of bacterial
biofilms with mucoid layers as their habitat. Pseudomonas
aeruginosa an opportunistic pathogen establishes itself inside the
airways of the patients and colonizes there permanently.
3. Quorum sensing mechanism
• Quorum sensing is a term that describes an environmental sensing system
that allows bacteria to monitor their own population density which
contributes significantly to the size and development of bio film.
• Pseudomonas aeruginosa produce and release the signaling molecules
which are known homoserine lactones (HSLs).
• After attainment of a threshold concentration these become detectable to
bacteria populations, which interact with cognate receptors to induce the
transcriptional expression of various target genes including those
encoding production of virulence factors, horizontal gene transfer, biofilm
formation etc.
• The HSLs can be detected via spectroscopy in the sputum sample which
indicates the presence of bacterial colonies of Pseudomonas aeruginosa
and early formation of biofilms.
4. Pseudomonas
aeruginosa comprises of
two AHL‐based QS
systems; Las and Rhl.
• The Las system has the
transcriptional regulator
LasR and its cognate AHL
signal, N‐(3‐oxododecano
yl)‐L‐homoserine lactone
(3‐0X0‐C12‐ HSL),
synthesized by the AHL
synthase LasI
• Similarly, the Rhl system
is comprised of RhlR
together with its cognate
AHL, N‐butyryl‐L‐homose
rine lactone (C4‐HSL),
synthesized by the RhlI
AHL synthase .
5. QS and biofilm formation
• Biofilms are communities of microorganisms that gets
attached to an inert or living surface by a self produced
polymeric substance (EPS)
• Biofilm formation is an important feature of
Pseudomonas aeruginosa pathogenicity and
contributes significantly to the resistance of bacteria to
aggressive antimicrobial therapy.
• Three independent studies have shown that
the P.aeruginosa genome is subject to AHL‐dependent
regulation .In reports the Las QS system was found to
be essential for creation of mature, differentiated
biofilms
6. • In a flow‐chamber set‐up, stalk‐like structures with
intervening water channels composed the PA01 biofilm.
In sharp contrast, the las1‐ biofilm was flat and
undifferentiated.
• Upon exposure to the detergent sodium dodecyl sulfate
(SDS), the las1‐ biofilm quickly dispersed from the
substratum, whereas the wild‐type biofilm remained
intact. So in addition to being structurally altered, the
mutant biofilm was functionally impaired in its ability to
resist biocidal agents.
• Since this inaugural report, several groups have
published findings supporting a role for QS, system,
in P.aeruginosa biofilm formation.
7. QS System in novel drugs and
therapeutics
• Signal molecules aid in biofilm formation which in turn confer various
properties of pathogenicity to the clinical isolates including drug
resistance. The use of quorum sensing signal blockers to attenuate
bacterial pathogenicty is therefore highly attractive, particularly with
respect to the emergence of multi antibiotic resistant bacteria.
AGENT COMMENTS
Macrolides Inhibition of QS regulated factors: inhibition
of alginate production
Garlic QS is inhibited by garlic and renders P
aeruginosa more sensitive to tobramycin
and host defences
Synthetic analogues Synthetic autoinducer analogues/ ligands;
inhibition of QS regulated factors and
biofilm formation.
Plant extracts Inhibition of LaA protease, LasB elastase,
and biofilm formation by several different
plant extracts.
QS Vaccine Specific antibody to 3-oxo-C-12-HSL plays a
protective role in infection
8. Conclusion
• QS plays an important role in maintaining the cell density
of population of bacteria.
• It allows signalling molecules to produce virulence
factors which help in biofilm formation.
• These signaling molecules and their metabolites can be
identified via spectroscopy.
• Early detection of Pseudomonas aeruginosa via quorum
sensing can help in prevention of bio film by inhibiting the
signaling AHL molecules.
• Due to inhibition of biofilm formation aggressive
antibiotic therapies can be applied to eliminate the
infection.