Direct methods of measurement of microbial growth includes various methods of enumeration of both viable and non viable cell also includes growth curve. Helpful for UG and PG programs of microbiology
Direct methods of measurement of microbial growth includes various methods of enumeration of both viable and non viable cell also includes growth curve. Helpful for UG and PG programs of microbiology
transduction is a process which that bacteriophage is transfer the genetic material to one to another bacterial cell .the transduction is have a two types that is generalized and specialized transduction .the two types of phage will be involve in the transduction process that is virulant and temptate pahge
Microbial interactions are ubiquitous, diverse, critically important in the function of any biological community.
The most common cooperative interactions seen in microbial systems are mutually beneficial. The interactions between the two populations are classified according to whether both populations and one of them benefit from the associations, or one or both populations are negatively affected.
transduction is a process which that bacteriophage is transfer the genetic material to one to another bacterial cell .the transduction is have a two types that is generalized and specialized transduction .the two types of phage will be involve in the transduction process that is virulant and temptate pahge
Microbial interactions are ubiquitous, diverse, critically important in the function of any biological community.
The most common cooperative interactions seen in microbial systems are mutually beneficial. The interactions between the two populations are classified according to whether both populations and one of them benefit from the associations, or one or both populations are negatively affected.
A lecture note on Microbial Growth and Nutrition, and Clones, Enzymes and Inf...Akram Hossain
This was an assignment of preparing “A lecture note on Microbial Growth and Nutrition, and Clones, Enzymes and Informative Hybridizations” for the course "General Microbiology"
Hope you will find it useful.
Microbiology is the study of a variety of living things, such as bacteria, fungus, and other tiny creatures, that are not visible to the naked eye. However, these little creatures are the foundation of all life on earth.. all types of living things that are invisible to the unaided eye.
Important categories have been divided based on certain traits in the study of bacteria in food. These classifications have no taxonomic relevance.
Food technology, food safety and hygiene, food poisoning, food genomics, and, more generally,
Prokaryote cells grow by increasing in cell number (as opposed to increasing in size).
Replication is by BINARY FISSION, the splitting of one cell into two
Therefore, bacterial populations increase by a factor of two (double) every generation time
The time required to for a population to double (doubling time) in number.
Ex. Escherichia coli (E. coli) double every 20 minutes
Ex. Mycobacterium tuberculosis double every 12 to 24 hours
It contain more information about Amino acids and their structure. Then , contain both physical and chemical properties. Next Classification of amino acids based on nutritional requirements, based on metabolic fate, Position of NH2 group, etc.,
Transmission electron microscopy (TEM)- by sivasangari Shanmugam. Transmission electron microscopy (TEM) is a technique used to observe the features of very small specimens.
SEM is a type of electron microscope designed for directly studying the surfaces of solid objects, that utilizes a beam of focused electron of relatively low energy as an electron probe that is scanned in a regular manner over the specimen.
Electron microscopy by SIVASANGARI SHANMUGAM.
Electron microscopy is a technique for obtaining high-resolution images of biological and non-biological specimens.
Phase contrast microscopy by sivasangari shanmugam
Phase-contrast microscopy, first described by Dutch physicist Frits Zernike in 1934.
It can be utilized to produce high-contrast images of transparent specimens, such as living cells (usually in culture), microorganisms, thin tissue slices, fibers, latex dispersions, glass fragments, and subcellular particles (including nuclei and other organelles).
BRIGHT FIELD MICROSCOPY by SIVASANGARI SHANMUGAM
bRIGHT FIELD MICROSCOPY is also called a compound microscope. The name bright - field is derived from the fact that the specimen is dark and contrasted by the surrounding bright viewing field.
DARK FIELD MICROSCOPY by SIVASANGARI SHANMUGAM
Dark-field microscopy is ideally used to illuminate unstained samples causing them to appear brightly lit against a dark background.
This type of microscope contains a special condenser that scatters light and causes it to reflect off the specimen at an angle
LIGHT MICROSCOPY by SIVASANGARI SHANMUGAM
The optical microscope, The functions of a light microscope is based on its ability to focus a beam of light through, which is very small and transparent, to produce an image.
(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.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
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
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
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.
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.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
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.
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 .
Body fluids_tonicity_dehydration_hypovolemia_hypervolemia.pptx
Microbial growth
1. GROWTH
DEFINITION
Growth implies increase in size resulting from cell multiplication and cell expansion, as
well as maturation of tissues. However, growth, while accentuating increased cell number and
size, also necessitates programmed cell death, leading to the production of the final body form.
Thus, growth is an incredibly complex phenomenon, which involves changes in body
form, metabolism, and body processes.
GROWTH CURVE
The bacterial growth curve represents the number of live cells in a bacterial population
over a period of time.
Bacterial growth curves a curve on a graph that shows the changes in size of a bacterial
population over time in a culture. The bacteria are cultured in sterile nutrient medium and
incubated at the optimum temperature for growth. Samples are removed at intervals and the
number of viable bacteria is counted.
1. LAG PHASE: This initial phase is characterized by cellular activity but not growth. A
small group of cells are placed in a nutrient rich medium that allows them to
synthesize proteins and other molecules necessary for replication. These cells increase in
size, but no cell division occurs in the phase.
2. EXPONENTIAL (LOG) PHASE: After the lag phase, bacterial cells enter the
exponential or log phase. This is the time when the cells are dividing by binary fission and
doubling in numbers after each generation time. Metabolic activity is high
as DNA, RNA, cell wall components, and other substances necessary for growth are
generated for division. It is in this growth phase that antibiotics and disinfectants are most
effective as these substances typically target bacteria cell walls or the protein synthesis
processes of DNA transcription and RNA translation.
3. STATIONARY PHASE: Eventually, the population growth experienced in the log phase
begins to decline as the available nutrients become depleted and waste products start to
2. accumulate. Bacterial cell growth reaches a plateau, or stationary phase, where the number of
dividing cells equals the number of dying cells. This results in no overall population growth.
Under the less favorable conditions, competition for nutrients increases and the cells become
less metabolically active. Spore forming bacteria produce endospores in this phase
and pathogenic bacteria begin to generate substances (virulence factors) that help them
survive harsh conditions and consequently cause disease.
4. DEATH PHASE: In the death phase, the number of living cells decreases exponentially
and population growth experiences a sharp decline. As dying cells lyse or break open, they
spill their contents into the environment making these nutrients available to other bacteria.
This helps spore producing bacteria to survive long enough for spore production. Spores are
able to survive the harsh conditions of the death phase and become growing bacteria when
placed in an environment that supports life.
GENERATION TIME
Generation time, the time that is required for a cell to complete one full growth cycle. If
every cell in the population is capable of forming two daughter cells, has the same average
generation time, and is not lost through lyses, the doubling time of the cell number in a
population will equal the generation time.
SYNCHRONOUS GROWTH
Synchronous growth is the growth of bacteria such that all the bacteria are at the same
stage in their growth cycle (e.g., exponential phase, stationary phase). Because the same cellular
reactions occur simultaneously throughout the bacterial population, synchronous growth permits
the detection of events not normally detectable in a single cell or in a population consisting of
bacteria in various stages of growth.
3. CONTINUOUS CULTIVATION
Continuous culture is a set of techniques used to reproducibly cultivate microorganisms
at submaximal growth rates at different growth limitations in such a way that
the culture conditions remain virtually constant (in 'steady state') over extended periods of time.
FACTORS INFLUENCING MICROBIAL GROWTH
TEMPERATURE
Psychrophiles are cold-loving bacteria. Their optimum growth temperature is between -
5C and 15C. They are usually found in the Arctic and Antarctic regions and in streams
fed by glaciers.
Mesophiles are bacteria that grow best at moderate temperatures. Their optimum growth
temperature is between 25C and 45C. Most bacteria are mesophilic and include common
soil bacteria and bacteria that live in and on the body.
Thermophiles are heat-loving bacteria. Their optimum growth temperature is between
45C and 70C and are commonly found in hot springs and in compost heaps.
Hyperthermophiles are bacteria that grow at very high temperatures. Their optimum
growth temperature is between 70C and 110C. They are usually members of the Archaea
and are found growing near hydrothermal vents at great depths in the ocean.
OXYGEN REQUIREMENTS
Obligate aerobes are organisms that grow only in the presence of oxygen. They obtain
their energy through aerobic respiration.
Microaerophils are organisms that require a low concentration of oxygen (2% to 10%) for
growth, but higher concentrations are inhibitory. They obtain their energy through
aerobic respiration.
4. Obligate anaerobes are organisms that grow only in the absence of oxygen and, in fact,
are often inhibited or killed by its presence. They obtain their energy through anaerobic
respiration or fermentation.
Aerotolerant anaerobes, like obligate anaerobes, cannot use oxygen to transform energy
but can grow in its presence. They obtain energy only by fermentation and are known as
obligate fomenters.
Facultative anaerobes are organisms that grow with or without oxygen, but generally
better with oxygen. They obtain their energy through aerobic respiration if oxygen is
present, but use fermentation or anaerobic respiration if it is absent. Most bacteria are
facultative anaerobes.
pH
Neutrophiles grow best at a pH range of 5 to 8.
Acidophiles grow best at a pH below 5.5.
Alkaliphiles grow best at a pH above 8.5.
OSMOSIS
Osmosis is the diffusion of water across a membrane from an area of higher water
concentration (lower solute concentration) to lower water concentration (higher solute
concentration). Osmosis is powered by the potential energy of a concentration gradient and does
not require the expenditure of metabolic energy. While water molecules are small enough to pass
between the phospholipids in the cytoplasmic membrane, their transport can be enhanced by
water transporting transport proteins known as aquaporins. The aquaporins form channels that
span the cytoplasmic membrane and transport water in and out of the cytoplasm.
To understand osmosis, one must understand what is meant by a solution. A solution
consists of a solute dissolved in a solvent . In terms of osmosis, solute refers to all the molecules
or ions dissolved in the water (the solvent). When a solute such as sugar dissolves in water, it
forms weak hydrogen bonds with water molecules. While free, unbound water molecules are
5. small enough to pass through membrane pores, water molecules bound to solute are not
concentration, the lower the concentration of free water molecules capable of passing through the
membrane.
Most bacteria require an isotonic environment or a hypotonic environment for optimum
growth. Organisms that can grow at relatively high salt concentration (up to 10%) are said to be
osmotolerant. Those that require relatively high salt concentrations for growth, like some of the
Archaea that require sodium chloride concentrations of 20 % or higher halophiles.
MINERALS
1. Sulfur
Sulfur is needed to synthesizes sulfur-containing amino acids and certain vitamins.
Depending on the organism, sulfates, hydrogen sulfide, or sulfur-containing amino acids may be
used as a sulfur source.
2. Phosphorus
Phosphorus is needed to synthesize phospholipids , DNA, RNA, and ATP . Phosphate ions
are the primary source of phosphorus.
3. Potassium, magnesium, and calcium
These are required for certain enzymes to function as well as additional functions.
4. Iron
Iron is a part of certain enzymes.
5. Trace elements
Trace elements are elements required in very minute amounts, and like potassium,
magnesium, calcium, and iron, they usually function as cofactors in enzyme reactions. They
include sodium, zinc, copper, molybdenum, manganese, and cobalt ions. Cofactors usually
function as electron donors or electron acceptors during enzyme reactions.