Air is not a natural environment for microorganisms. Microorganisms present in air are liberated from various other sources. These various sources include soil, water, plant and animal surfaces and human beings.
Air Microbiology. Aerobiology is defined as the study of life present in the air. Aeromicrobiology relates to the study of environmentally relevant microorganisms. ... In dry whether the microbial load of air is high while in wet weather the rain washes the microorganisms from the air.
Air microbiology is a scientific discipline that concerns the microorganisms, including bacteria, archaea, fungi and viruses, in the atmospheric air. It is a subdiscipline of environmental microbiology.
Air microbiology study of microbes suspended in air. Microflora of air depend on the location and environmental condition at particular place. There are different types of air trapping devices like Slit Sampler, Andersons samplers, Impingers etc. Air borne diseases mainly spread by droplet infection, contact with infected things . Air borne diseases are discussed and concluded with control of air borne microbes.
Air is not a natural environment for microorganisms. Microorganisms present in air are liberated from various other sources. These various sources include soil, water, plant and animal surfaces and human beings.
Air Microbiology. Aerobiology is defined as the study of life present in the air. Aeromicrobiology relates to the study of environmentally relevant microorganisms. ... In dry whether the microbial load of air is high while in wet weather the rain washes the microorganisms from the air.
Air microbiology is a scientific discipline that concerns the microorganisms, including bacteria, archaea, fungi and viruses, in the atmospheric air. It is a subdiscipline of environmental microbiology.
Air microbiology study of microbes suspended in air. Microflora of air depend on the location and environmental condition at particular place. There are different types of air trapping devices like Slit Sampler, Andersons samplers, Impingers etc. Air borne diseases mainly spread by droplet infection, contact with infected things . Air borne diseases are discussed and concluded with control of air borne microbes.
Microbiology of Air
Aero-microbiology
Airborne diseases.
Sources of microorganisms in Air
Microbes in atmosphere
Bioaerosol
“Study of living microbes suspended in air”
Various layers present in the atmosphere at height of 1000km
Nearest to earth is troposphere
troposphere contains heavy load of microorganisms
Boundary layer responsible for transport of particles both short and long distances
Bio Aerosol
“particles release from terrestrial and marine ecosystem into the atmosphere they consist of both living and non living components
including organisms, dispersal method of organisms and excretion
Air sanitation is the system of removing the impurities present in air inside buildings to protect people from infections. Sanitation of air is essential in enclosed places like hospitals and operation rooms.
Introduction
Type of pesticides
Advantage & disadvantages of pesticides
Degradation of pesticide
Microbial degradation of pesticides
Mode of microbial metabolism of pesticides
Strategies for biodegradation
Approaches for biodegradation of pesticide
Chemical reaction leading biodegradation of pesticide
Metabolism of pesticides by MO
Metabolism of DDT
Microbiology of Air
Aero-microbiology
Airborne diseases.
Sources of microorganisms in Air
Microbes in atmosphere
Bioaerosol
“Study of living microbes suspended in air”
Various layers present in the atmosphere at height of 1000km
Nearest to earth is troposphere
troposphere contains heavy load of microorganisms
Boundary layer responsible for transport of particles both short and long distances
Bio Aerosol
“particles release from terrestrial and marine ecosystem into the atmosphere they consist of both living and non living components
including organisms, dispersal method of organisms and excretion
Air sanitation is the system of removing the impurities present in air inside buildings to protect people from infections. Sanitation of air is essential in enclosed places like hospitals and operation rooms.
Introduction
Type of pesticides
Advantage & disadvantages of pesticides
Degradation of pesticide
Microbial degradation of pesticides
Mode of microbial metabolism of pesticides
Strategies for biodegradation
Approaches for biodegradation of pesticide
Chemical reaction leading biodegradation of pesticide
Metabolism of pesticides by MO
Metabolism of DDT
introduction of environment engineering,structures of atmosphere, its type , classification of microorganisms and growth pattern, roll of microorganisms
A SEMINAR REPORT ON AIR MICROFLORA.
In addition to gases, dust particles and water vapour, air also contains microorganisms. There are vegetative cells and spores of bacteria, fungi and algae, viruses and protozoan cysts (Rintala et al., 2018).
Since air is often exposed to sunlight, it has a higher temperature and less moisture. So, if not protected from desiccation, most of these microbial forms will die. Air is mainly it transport or dispersal medium for microorganisms (Rintala et al., 2018).
They occur in relatively small numbers in air when compared with soil or water. The microflora of air can be studied under two headings outdoor and indoor microflora (Rintala et al., 2018).
The use of high efficient particulate air filters and immunization should be employed to control the spread of these airborne diseases. Obviously, the presence of a good ventilation system inside buildings eliminates to some extent the influence of indoor and outdoor sources. Proper ventilation helps to dilute the negative effects of indoor and outdoor air.
Introduction
History
Definition
Aerobiological pathway
Fundamentals of Aerobiology
New techniques for advancing aerosol science and aerobiology
Airborne Diseases
Conclusion
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.
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.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
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.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
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.
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.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
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.
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.
2. INTRODUCTION
◦ Air, mixture of gases comprising the Earth’s atmosphere. The mixture contains a
group of gases of nearly constant concentrations, variable amounts of water
vapor and dust particles.
◦ The air in our atmosphere is composed of molecules of different gases. The most
common gases are nitrogen (78%), oxygen (about 21%), and argon (almost 1%).
Other molecules are present in the atmosphere as well, but in very small
quantities.
◦ The earth's atmosphere is teeming with airborne microorganisms. These
organisms are thought to exhibit correlations with air pollution and weather.
◦ Air is an unfavorable environment for microorganisms, in which they cannot
grow or divide. It is merely a place which they temporarily occupy and use for
movement.
◦ Air lacks nutrients and water required for growth of microorganisms.
3. INTRODUCTION
✓Aeromicrobiology is that zone of biological science which describes the study of air
living microorganisms.
✓These aerial microorganisms are called bioaerosols.
✓These bioaerosols have tremendous capacity to create disease not only in human beings
but also in several other living organisms.
✓The troposphere which is the most nearest aerial layer of earth exhibit the overload of
microorganisms.
4. INTRODUCTION
✓As they travel a long route by air they can cause several diseases and which spread not only in human beings
but also in plants, livestock etc and lead to severe damage.
✓These microbial emissions of air can play a vital role in environmental hygiene.
✓Microbes become suspended in the clouds first, then they transform the chemical composition of clouds by
causing several chemical reactions.
✓Most airborne bacteria originate from natural sources such as the soil, lakes, oceans,
animals, and humans.
✓These aerial microorganisms may spread throughout a long distance after being suspended.
✓Viable airborne microorganisms are not air pollutants, but should be considered as a factor
affecting air quality.
5. DEFINITION
◦ Aerobiology is defined as the study of life present in the air.
◦ Aeromicrobiology relates to the study of environmentally relevant microorganisms.
◦ Microorganisms exist within 300-1000 feet of earth’s surface that have become attached
to fragments of dried leaves, straw or dust particles light enough to be blown by wind.
◦ In dry whether the microbial load of air is high while in wet weather the rain washes the
microorganisms from the air.
6. Air is a poor medium for microbial growth – too dry and no nutrients.
Spore forming and Gram- positive bacteria are resistant to drying.
Dust, water droplets in air carry microbial populations from one place to another
Sneezing, coughing, talking are efficient methods of transferring microbes from one
respiratory tract to another 100 m/sec, 10000 – 100000 bacteria.
Liquid and dust particles settle in the respiratory tract depending on their velocity and size.
Microorganisms colonize specific locations in the respiratory tract.
7. PHYSICAL HABITATS IN AIR
◦ There are two microbial habitats in air-
◦ 1. Atmosphere 2. Clouds
Atmosphere: The layers of atmosphere are differentiated according to intensity of light, variation of temperature
low amount of organic matter and a scarcity of available water making it a non-hospitable environment for
microbes. But these can be deposited by gravity that make them to contact with earth’s surface. By this way the
microbes gradually suspend in the lower part of atmosphere.
◦ There are five layers of atmosphere:
I) Troposphere –> 6-20 km
II) Stratospheres –> 50 km
III)Mesosphere –> 85 km
IV)Thermosphere –> 690 km
V) Exosphere –>10,000 km
8. Structure of the Atmosphere
• Troposphere: This layer is the most important layer of the
atmosphere. Its average height is 13 km. The air we breathe exists
here.
• Stratosphere: It lies above the troposphere which extends up to a
height of 50 km. This layer is almost free from clouds and associated
weather phenomenon. It contains a layer of ozone gas.
• Mesosphere: This is the third layer of the atmosphere. It lies above
the stratosphere. It extends up to the height of 80 km. Meteorites burn
up in this layer on entering from the space.
• Thermosphere: In thermosphere temperature rises very rapidly with
increasing height. Ionosphere is a part of this layer. It extends between
80-400 km. This layer helps in radio transmission.
• Exosphere: The upper most layer of the atmosphere is known as
exosphere. This layer has very thin air. Light gases like helium and
hydrogen float into the space from here
9. PHYSICAL HABITATS IN AIR
Clouds
❖Clouds are another kind of microbial habitat.
❖A visible mass of condensed watery vapor floating in the atmosphere, typically high above the general level of
the ground.
❖Actually clouds acidic environment favours (PH =3-7) the extremophiles growth and suspension.
❖The building blocks of clouds are water and particles—of dust, dirt.
❖They attract water vapor and as they ascend the vapor condenses to form liquid water or ice, which results in
the formation of tiny globules called cloud droplets.
❖Much smaller than raindrops, cloud droplets are extremely light and a mass while they float, mixing with air to
form the fluffy formations we see suspended in the sky.
❖Clouds are alive with tiny bacteria that grab up water vapor in the atmosphere to make cloud droplets,
especially at warmer temperatures.
10. MICROBIAL COMMUNITIES IN AIR:
Several types of microorganisms such as, bacteria, virus, fungi, yeast and
protozoans form aerosols.
Then these microorganisms have to adapt with the harsh conditions of
atmosphere just for survival. As these can survive the extreme condition some of
them can form endospore.
Bacteria:
Bacillus anthracis, gram positive in nature and it can survive in aerosol. This
bacteria is responsible for anthrax which is associated with dangerous respiratory
diseases of human.
Fungi:
Aspergillus fumigatus is most dangerous aerial fungal pathogen and it is able to
cause human lungs diseases when their conidia are inhaled. There are several
viral pathogens in aerosol in atmosphere which have the capacity to develop
severe diseases in human beings as well as in other animals. The toxins secreted
from airborne microorganisms are highly responsible for severe diseases in
human. A very common type of spores found in air is that of conidia.
11. Virus:
The air is also occupied by viruses. Among those that demonstrate the highest resistance are those with enveloped
nucleocapsids, such as influenza viruses. Among viruses without enveloped nucleocapsids, enteroviruses
demonstrate a relatively high resistance. Viruses are usually more resistant than bacteria.
Lipopolysaccharide (LPS) is one of the most affective airborne toxin that develop from the gram negative
bacteria’s outer membrane. After getting associated with dust in air the LPS may lead to acute respiratory
diseases such as- chest tightness, coughing, fever etc.
What types of dangers are connected to the presence of microorganisms in air?
•Infectious diseases (viral, bacterial, fungal and protozoan),
•Allergic diseases
•Poisoning (exotoxins, endotoxins, mycotoxins).
Bioaerosols may carry microorganisms other than those which evoke respiratory system diseases. The intestinal
microorganisms contained in aerosols may, after settling down, get into the digestive system (e.g. by hands)
causing various intestinal illnesses.
12. Bioaerosols
▪ Bioaerosols are defined as particles of microbial, plant, or animal origin and oftentimes are called “organic dust.”
▪ They can include live or dead bacteria, fungi, viruses, allergens, bacterial endotoxins (components of cell membranes
of Gram-negative bacteria), antigens (molecules that can induce an immune response), toxins (toxins produced by
microorganisms), mycotoxins (toxins produced by fungi), glucans (components of cell walls of many molds), pollen,
and plant fibers.
▪ Microorganisms in air occur in a form of colloidal system or the so-called bioaerosol.
▪ Many of these kinds of bioaerosols are known to cause a variety of human impacts such as infection and sensitivity
over even short periods of time.
▪ Bioaerosols are airborne particles, solid or liquid.
▪ They can be large molecules or volatile compounds.
▪ They contain living organisms.
▪ They will vary in size from a fraction of a micron to around 100 microns.
13. SOURCES OF MICROBES IN AIR
• Although there are lots of microorganisms in air but air is not the natural habitat of all type of
microorganisms because it does not constitute perfect moisture and nutrient for the growth of
microorganisms.
• Infectious dust, droplets, industrial aerial emissions are the major sources of microbes in air today. Actually
big sized aerial droplets get dry on air surfaces.
• The nasal and throat discharges from a patient can be the major source of infectious dust and it is seen
that after getting dried these discharges along with several microorganisms freely float in the air.
• Besides this there is also the presence of droplets in air. The vital sources of droplets are sneezing,
coughing and talking of patients.
• The oral discharges along with mucus of those patients can bear lots of severe infectious microorganisms
which readily spread in the air and play a vital role in the disease development.
• The industrial aerial emissions are full of toxic gases and these gaseous particles are also a major source of
infectious microorganisms in air.
• Atmospheric humidity, temperature are the major controllers of survival of microorganisms in air.
14. Resistance of microorganisms
Humidity:
• The content of water in air is one of the major factors determining the ability to survive.
• At a very low humidity and high temperature cells face dehydration, whereas high humidity may give cells
protection against the solar radiation.
• Microorganisms react differently to humidity variations in air, but nevertheless most of them prefer high
humidity.
• Gram-negative bacteria and enveloped viruses (e.g. influenza virus) deal better with low air humidity which
is contrary to gram-positive bacteria and non-enveloped viruses (e.g. enteroviruses) that have higher survival
rates in high air humidity.
Temperature:
• Temperature can indirectly affect cells by changing the relative-air humidity (the higher the temperature, the
lower the relative humidity) or a direct affect, causing, in some extreme situations, cell dehydration and
protein denaturation (high temperatures) or crystallization of water contained within cells (temperatures
below 0°C).
• Therefore, it can be concluded that low temperatures (but above 0°C) are optimal for the bioaerosol.
According to some researchers the optimal temperatures are above 15°C.
15. Indoor Microflora:
The air found inside the building is referred to as indoor air.
The commonest genera of fungi in indoor air are penicillium, Aspergillus, the
commonest genera of bacteria found in indoor air are Staphylococci, Bacillus and
Clostridium.
Outdoor Microflora:
The air in the atmosphere, which is found outside the buildings, is referred to as
outside air. The dominant microflora of outside air are fungi.
The two common genera of fungi are cladosporium and sporobolomyces, besides
these two the fungi found generally in air are Aspergillus, Alternaria, Phytophthora
and Erysiphe.
The outdoor air also contains besidispores, ascopres of yeast, fragments of
mycelium and canidia of molds.
Among the bacterial genera Bacillus and clostridium, sarcina, mirococcus,
Corynebacterium and Achromobacter are widely found in the outside air, the
number and kind of microorganism may vary from place to place, depending upon
the human population densities.