Viruses are ultramicroscopic, acellular parasites that can only replicate inside host cells. They are much smaller than bacteria and can only be seen with electron microscopes. Viruses infect all forms of life from animals and plants to bacteria and archaea. They contain either DNA or RNA and have protein capsids that protect their genetic material. Viruses are obligate intracellular parasites as they cannot carry out metabolism and require host cells to replicate. Examples of viral diseases include influenza, hepatitis, AIDS, and the common cold.
Major divisions in Bergey's manual of systematic bacteriology 2nd edition presented for examination purpose. Pinned important points are compiled here for students.
Major divisions in Bergey's manual of systematic bacteriology 2nd edition presented for examination purpose. Pinned important points are compiled here for students.
Obligate intracellular, unable to self-replicate.
Once inside living cells, viruses induce the host cell to synthesize virus particles.
The genome is either DNA or RNA (single or double stranded).
Viruses do not have a system to produce ATP.
Viruses range in size from 25 to 270 nm.
Viral tropism!!
The classification of viruses is based on nucleic acid type, size and shape of virion, and presence or absence of an envelope.
Viral Structure
I . Virion is the entire viral particle.
2. Capsid is the protein coat that encloses the genetic material.
3. Capsomer is the protein subunit that makes up the capsid.
4. Nucleocapsid is composed of the capsid and genetic material.
5. The envelope is the outer coating composed of a phospholipid bilayer, which is composed of viral-encoded glycoproteins and sometimes viral encoded matrix proteins. The envelope is derived from a host cell's membrane.
Some viruses use the plasma membrane, whereas others use endoplasmic reticulum, Golgi, or nuclear membranes. Naked nucleocapsids are viruses with no envelopes.
Mycorrhiza-definition, Types, VAM, Symbiotic development mechanism between AM fungi and host root, pre-, early- and mature- symbiotic phases, Myc factors, Appresorium and arbuscule development, nutrient exchange
CaMV Genome organization & their replication, Cauliflower Mosaic Virus belong to Group VII (ds-DNA-RT), Open circular double stranded DNA of 80kb and CaMV replicates by reverse transcription
Obligate intracellular, unable to self-replicate.
Once inside living cells, viruses induce the host cell to synthesize virus particles.
The genome is either DNA or RNA (single or double stranded).
Viruses do not have a system to produce ATP.
Viruses range in size from 25 to 270 nm.
Viral tropism!!
The classification of viruses is based on nucleic acid type, size and shape of virion, and presence or absence of an envelope.
Viral Structure
I . Virion is the entire viral particle.
2. Capsid is the protein coat that encloses the genetic material.
3. Capsomer is the protein subunit that makes up the capsid.
4. Nucleocapsid is composed of the capsid and genetic material.
5. The envelope is the outer coating composed of a phospholipid bilayer, which is composed of viral-encoded glycoproteins and sometimes viral encoded matrix proteins. The envelope is derived from a host cell's membrane.
Some viruses use the plasma membrane, whereas others use endoplasmic reticulum, Golgi, or nuclear membranes. Naked nucleocapsids are viruses with no envelopes.
Mycorrhiza-definition, Types, VAM, Symbiotic development mechanism between AM fungi and host root, pre-, early- and mature- symbiotic phases, Myc factors, Appresorium and arbuscule development, nutrient exchange
CaMV Genome organization & their replication, Cauliflower Mosaic Virus belong to Group VII (ds-DNA-RT), Open circular double stranded DNA of 80kb and CaMV replicates by reverse transcription
Introduction to Microbiology And Common Micro-Organisms, EpidemiologyMonika P. Maske
Introduction to Microbiology, Classification Of Micro-Organisms, Bacteria , Classification of Bacteria Depend on Shape and Characteristic Arrangement, Algae,Fungi, Moulds And Yeasts, Spores, Viruses, Protozoa, Rickettsia & Mycoplasma, Identification of Bacteria, Scope of Microbiology, Introduction to Epidemiology, Applications of Epidemiology,Definitions.
Powerpoint on viruses, bacteria, protists and Fungi. Intended for the SA Grade 11 Life Sciences syllabus. Includes information on HIV, virus reproduction, malaria, TB, thrush, characteristics of microbes etc. Hope it helps!
Characteristics of pet/virus , plant disease , pest life cycle, regarding and repeating plant disease , selecting treatment methods, Control plant pest / virus .
Lecture 1 - Introduction To Virology.pptxJonesChipinga
This lecture outlines why we study viruses, the virosphere,bacteriophage plaque assay, the nature of viruses, properties of viruese, viral genomics and comparison of viruses to other cells.
Ascent of sap- Transpiration pull theory, Transpiration-Types of transpiration, mechanism of transpiration-Starch sugar interconversion theory and Potassium pump theory
(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.
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/
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
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.
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.
1. Viruses: Introduction and general
characters
Dr. Dhole N. A.
Department of Botany,
Digambarrao Bindu ACS College, Bhokar
2. Introduction:
• The branch of science that deals with the study of viruses is called
virology.
• The scientists who work in this branch are called virologists.
• Viruses are ultramicroscopic, acellular, infectious, nucleoproteinous,
obligate parasites that can only replicate inside a host cell.
• Viruses are much smaller than bacteria, their size is variable and
which can cross the bacterial filter.
• The extracellular forms of viruses are inert particles and are known as
virions.
• From a biological perspective, viruses cannot be classified either as
living organism or non-living.
3. On the basis of the host cell they infect,
• viruses infect to animals are called as zoophages (animal viruses),
• phytophages (plant viruses),
• phycophages (algal viruses),
• mycophages (fungal viruses),
• zymophages (yeast viruses),
• bacteriophages (bacterial viruses),
• cyanophages (infecting cyanobacteria),
• coliphages (infecting E. coli bacteria).
4. • Viruses are visible only under the electron microscope .
• The discovery of virus cannot be credited to any one scientist but it
was the contribution of many scientists.
• Louis Pastuer (1884): He coined the term ‘viruses’ (virus = poison)
which are smaller than bacteria. He first demonstrated that viral
diseases like rabies can be transmitted for one host to another.
• Adolf Mayer (1886): He first discovered the mosaic disease of
tobacco.
• D.J. Iwanowsky (1892)- He first discovered the Tobacco Mosaic Virus
causing mosaic disease of tobacco.
• W.M. Stanley (1935): He first isolated and crystallized TMV. For this
Stanley shared the 1946 Nobel Prize with Northrop and Sumner who
had earlier crystallized the enzyme urease for the first time. Stanley is
known as the ‘father of virology’.
5. General Characters of Viruses:
• Viruses are non-living, non-cellular structure.
• They do not have a cytoplasm or any kind of cellular organelles to
carry out any kind of metabolism.
• Viruses are able to infect all living forms including plants, animals,
human beings and even micro-organism.
• Viruses are obligate intracellular parasites they require a living cell or
organism for its multiplication.
• Viruses can be observed only under the electron microscope.
• They are 10 to 100 times smaller than bacteria and its size ranges
from 20 to 300 nm so these viruses can pass easily through
bacteriological filters. They are filterable.
6. • Size of viruses is measure with the help Ultrafiltration,
ultracentrifugation and electron microscopy.
• Viruses do not have any kind of cellular organization.
• Viruses have spikes which help the virus to attach on the host cell.
• It contains either DNA or RNA as a nuclear material.
• As we know viruses are an obligate intracellular parasite and lack the
essential enzyme for protein and nucleic acid synthesis. These viruses
depend on the host cell for its replication and multiplication.
• Viruses are unaffected by antibiotics, there are many differences
between micro-organism and viruses
7. • Viruses are of great concern in the field of medical microbiology
because they are responsible for various human diseases.
• Examples of diseases caused by viruses are Rabies, AIDS, Mumps,
Hepatitis, Influenza, Dengue, common cold and many more diseases
are caused due to viruses.
• Viron is an extracellular infectious particle of the virus.
• Viron contains essential nucleic acid which is protected by the protein
coat called as the capsid.
• The function of the capsid is to protect nucleic acid from nucleases
and other environmental factors.
• The capsid is made up of polypeptide molecules.
8. • Capsid shows two types of symmetry that are cubical or icosahedral
symmetry and helical symmetry.
• Icosahedral symmetry shows 12 vertices and 20 sides.
• The icosahedral contains two types of capsomers Pentons at the
vertices and hexons at the Facets or sides.
• Different viruses have different shapes, most of the animal viruses are
roughly spherical in shape, pox virus is brick shape, TMV is rod shape
etc.
• Viruses may be enveloped or non-enveloped.
• Envelop is made up of lipoproteins and is derived from host cell
membrane.
9. • Viruses require a living media like the embryonic egg, cell culture or
bacterial cells.
• Viruses are classified on the basis of morphology, chemical
composition, and mode of replication.
