Concept of virology
Viruses
Types of viruses
Viral characteristics
Virion
Size and Shape
Structure
Replication
Viral Variation
Classification
Quiz
BEST OF LUCK
Viruses are microscopic organisms that exist almost everywhere on earth. They can infect animals, plants, fungi, and even bacteria.Viruses vary in complexity. They consist of genetic material, RNA or DNA, surrounded by a coat of protein, lipid (fat), or glycoprotein. Viruses cannot replicate without a host, so they are classified as parasitic.They are considered the most abundant biological entity on the planet.
Here we discuss the general properties of viruses in detail.
Replication of virus is very complicated process.
Virus never reproduce by division.
They are replicated by a process in which all components of virus are produced separately and are assembled into intact virion.
For replication of virus host is necessary.
Virus are host specific.
Host may be bacteria, plant ,animal.
Animal viruses are self replicating, intracellular parasites that completely rely on host animal cell for reproduction. They use the host's cellular components to replicate, then leaves the host cell to infect other cells.
The Paramyxoviridae is a family of single-stranded RNA viruses known to cause different types of infections in vertebrates. Examples of these infections in humans include the measles virus, mumps virus, parainfluenza virus, and respiratory syncytial virus (RSV).
VIRUSES CLASSIFICATION , LIFE CYCLE OF VIRUSES. CHARACTERISTICS OF VIRUSES Shylesh M
VIRUSES
LIFE CYCLE OF BACTERIOPHAGES
The word virus is derived from Latin word venom which means poisonous fluid that causes infection.
The branch of science that deals with the study of viruses is called Virology. It is the branch of Microbiology.
They show living characters inside the host and non living characters outside the host.
They contain either DNA or RNA as genetic material.
They have different size and shape. They cause diseases in plants, animals and micro-organisms .
Not cellular
Cannot carry on metabolic activities independently.
Contain either DNA or RNA, not both ( true cells contain both ).
Lack ribosomes and enzymes necessary for protein synthesis.
Reproduce only within cells they infect.
CLASSIFICATION OF VIRUSES
Holmes, in 1948, proposed a simple system of classifying viruses based on the type of cell (host) they infect:
Phytophagineae: They infect plants and they RNA as their genetic material. Eg: TMV,CaMV.
Zoophagineae: They infect animals and they have mostly DNA as their genetic material. Eg: Polio virus.
Pagineae: They infect bacterial cells, called bacteriophages they usually have DNA as genetic material.
Based on the viral envelope
Named after David Baltimore, a noble prize winning biologist n 1971.
1. dsDNA viruses Eg: Adenoviruses, Herpiviruses.
2. ssDNA viruses Eg: Paravoviruses.
3. dsRNA viruses Eg: Reoviruses.
4. (+)ssRNA viruses Eg: Picornaviruses.
5. (-)ssRNA viruses Eg: Orthomyxoviruses.
6. ssRNA-RT viruses Eg: Retroviruses.
7. dsDNA-RT viruses Eg: Hepadnaviruses.
Tobacco mosaic:
Causative agent: Tobacco mosaic virus (TMV)
Symptoms: The leaves of infected plants develop mosaic patches ,it is due to destruction of chlorophyll or due to production of abnormal chlorophyll .blisters appear in the region of dark green spots these may be regular or irregular in advanced stages leaves curl and get distorted.
Adsorption of the virion to the bacterial cell.
Penetration and decoating of the nucleic acid .
Protein synthesis.
Breakdown of bacterial DNA.
Arrest of host cell development.
Replication of phage DNA.
Maturation of infective progeny.
Lysis and release of newly formed phages.
Holmes, in 1948, proposed a simple system of classifying viruses based on the type of cell (host) they infect:
Phytophagineae: They infect plants and they RNA as their genetic material. Eg: TMV,CaMV.
Zoophagineae: They infect animals and they have mostly DNA as their genetic material. Eg: Polio virus.
Pagineae: They infect bacterial cells, called bacteriophages they usually have DNA as genetic material.
Viruses are microscopic organisms that exist almost everywhere on earth. They can infect animals, plants, fungi, and even bacteria.Viruses vary in complexity. They consist of genetic material, RNA or DNA, surrounded by a coat of protein, lipid (fat), or glycoprotein. Viruses cannot replicate without a host, so they are classified as parasitic.They are considered the most abundant biological entity on the planet.
Here we discuss the general properties of viruses in detail.
Replication of virus is very complicated process.
Virus never reproduce by division.
They are replicated by a process in which all components of virus are produced separately and are assembled into intact virion.
For replication of virus host is necessary.
Virus are host specific.
Host may be bacteria, plant ,animal.
Animal viruses are self replicating, intracellular parasites that completely rely on host animal cell for reproduction. They use the host's cellular components to replicate, then leaves the host cell to infect other cells.
The Paramyxoviridae is a family of single-stranded RNA viruses known to cause different types of infections in vertebrates. Examples of these infections in humans include the measles virus, mumps virus, parainfluenza virus, and respiratory syncytial virus (RSV).
VIRUSES CLASSIFICATION , LIFE CYCLE OF VIRUSES. CHARACTERISTICS OF VIRUSES Shylesh M
VIRUSES
LIFE CYCLE OF BACTERIOPHAGES
The word virus is derived from Latin word venom which means poisonous fluid that causes infection.
The branch of science that deals with the study of viruses is called Virology. It is the branch of Microbiology.
They show living characters inside the host and non living characters outside the host.
They contain either DNA or RNA as genetic material.
They have different size and shape. They cause diseases in plants, animals and micro-organisms .
Not cellular
Cannot carry on metabolic activities independently.
Contain either DNA or RNA, not both ( true cells contain both ).
Lack ribosomes and enzymes necessary for protein synthesis.
Reproduce only within cells they infect.
CLASSIFICATION OF VIRUSES
Holmes, in 1948, proposed a simple system of classifying viruses based on the type of cell (host) they infect:
Phytophagineae: They infect plants and they RNA as their genetic material. Eg: TMV,CaMV.
Zoophagineae: They infect animals and they have mostly DNA as their genetic material. Eg: Polio virus.
Pagineae: They infect bacterial cells, called bacteriophages they usually have DNA as genetic material.
Based on the viral envelope
Named after David Baltimore, a noble prize winning biologist n 1971.
1. dsDNA viruses Eg: Adenoviruses, Herpiviruses.
2. ssDNA viruses Eg: Paravoviruses.
3. dsRNA viruses Eg: Reoviruses.
4. (+)ssRNA viruses Eg: Picornaviruses.
5. (-)ssRNA viruses Eg: Orthomyxoviruses.
6. ssRNA-RT viruses Eg: Retroviruses.
7. dsDNA-RT viruses Eg: Hepadnaviruses.
Tobacco mosaic:
Causative agent: Tobacco mosaic virus (TMV)
Symptoms: The leaves of infected plants develop mosaic patches ,it is due to destruction of chlorophyll or due to production of abnormal chlorophyll .blisters appear in the region of dark green spots these may be regular or irregular in advanced stages leaves curl and get distorted.
Adsorption of the virion to the bacterial cell.
Penetration and decoating of the nucleic acid .
Protein synthesis.
Breakdown of bacterial DNA.
Arrest of host cell development.
Replication of phage DNA.
Maturation of infective progeny.
Lysis and release of newly formed phages.
Holmes, in 1948, proposed a simple system of classifying viruses based on the type of cell (host) they infect:
Phytophagineae: They infect plants and they RNA as their genetic material. Eg: TMV,CaMV.
Zoophagineae: They infect animals and they have mostly DNA as their genetic material. Eg: Polio virus.
Pagineae: They infect bacterial cells, called bacteriophages they usually have DNA as genetic material.
Viruses are infectious intracellular obligate parasites with subcellular level of organisation and without protoplasm, cell, cell organells and the molecular machineries for energy metabolism and protein synthesis,Grouped on the basis of size and shape, chemical composition and structure of the genome and mode of replication
most viruses have a specific shape that is determined by the capsomeres or the envelope.
Capsid symmetry - Three types
(1) HELICAL CAPSID
(2) ICOSAHEDRALCAPSID
(3) COMPLEX CAPSID
Capsid - large macromolecular structures.
Made up of proteins called capsomers.
Chemical unit of capsomers are polypeptide chain.
Capsid - surrounded by lipoprotein layer called envelop
Envelop is made up of proteins and glycoproteins
Presence of lipid -envelope seems flexible and loose.
Envelope is composed of both the host viral components.
projections on the envelope known as spikes/peplomers which are arranged into distinct units.
General Characters and Classification of Viruses. Includes ICTV classification and Baltimore classification of viruses. A brief explanation of the Viral structure and Lifecycle.
Viruses are infectious intracellular obligate parasites with subcellular level of organisation and without protoplasm, cell, cell organells and the molecular machineries for energy metabolism and protein synthesis,Grouped on the basis of size and shape, chemical composition and structure of the genome and mode of replication
most viruses have a specific shape that is determined by the capsomeres or the envelope.
Capsid symmetry - Three types
(1) HELICAL CAPSID
(2) ICOSAHEDRALCAPSID
(3) COMPLEX CAPSID
Capsid - large macromolecular structures.
Made up of proteins called capsomers.
Chemical unit of capsomers are polypeptide chain.
Capsid - surrounded by lipoprotein layer called envelop
Envelop is made up of proteins and glycoproteins
Presence of lipid -envelope seems flexible and loose.
Envelope is composed of both the host viral components.
projections on the envelope known as spikes/peplomers which are arranged into distinct units.
General Characters and Classification of Viruses. Includes ICTV classification and Baltimore classification of viruses. A brief explanation of the Viral structure and Lifecycle.
This presentation gives a detail overview on Viruses - Morphology and Classification. The presentation is helpful for students of B. Pharm Second Year and those who wants to gain basic knowledge about Viruses.
Subject - Microbiology
Morphology, Classification, Cultivation and Replication of VirusKrutika Pardeshi
This presentation is Useful for B. Pharmacy SEM III Students to study the Topic Fungi According to PCI Syllabus.
It Consist of Morpholoy of Fungi, Cultivation , Replication and Classification of Virud
Virus, infectious agent of small size and simple composition that can multiply only in living cells of animals, plants, or bacteria. The name is from a Latin word meaning “slimy liquid” or “poison.”
History of arthropods.
Relation with annelids.
Characteristic features.
Circulatory system.
Classification upto subphylum
Phylum Upto Classes
Metamrization
Tegmatization
Why Tegmatization is better?
Exoskeleton
Metamorphoses
Habitat and Adaptations
Economic Gains
Economic Losses
Presentation
Best of Luck
The Science of Zoology
Zoology As Part of Biology
Branches of Zoology
Branches of Zoology related to the medical science
Importance in daily life
The Importance of Animals in Biomedical Research
Nematode .......parasites of human and further phylogenetic considerationAnzaDar3
Phylum Nematoda
Some important Nematode Parasites of Human
The giant intestinal roundworm of humans
The Human Pinworm
The new World Hookworm
The Porkworm
The Filarial Worm
Further Phylogenetic Considerations
References
Introduction to phylum Kinorhyncha
Introduction to phylum Nematoda
Characteristics of phylum Nematoda
Locomotion in Nematodes
External and Internal features
Feeding and Digestive systems
Reproduction and development in Nematodes
Some other organ systems
Presentation
Best of Luck
Class Bivalvia
Shell and associated structures
Gas exchange ,filter feeding and digestion
Reproduction and development
Other maintenance functions of Class Bivalves
Diversity in Bivalves
Presentation
Best of luck
Phylum Platyhelminthes
Class Turbellaria
Class Monogenea
Class Trematoda
Class Cestoidea
Characteristics
Reproduction and Development
Presentation
Best of Luck
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
2. General Virology
Concept of virology
Viruses
Types of viruses
Viral characteristics
Virion
Size and Shape
Structure
Replication
Viral Variation
Classification
3. Concept of Virology
• Virology is the bioscience for study of
viral nature, and the relationship
between virus and host.
• Viruses often cause serious diseases,
relate to some cancers and congenital
deformities, also can be used as tool for
genetic engineering.
4. Definition of Virus
Viruses may be defined as acellular organisms
whose genomes consist of nucleic acid protected
by the protein coat, and which obligately
replicate inside host cells and too small to be seen
by electron microscopy.
5. History
L. Pasteur in 1884 and A. Mayer in 1886
• Studied on mosaic disease of Tobacco plant/ transformation of disease
D. Iwanowsky in 1892
• Studied on extract from tobacco plant suffering from mosaic disease.
Filtration mechanism
M. Beijernick in 1898
• Disease causing filterable viruses multiply in host
F. Twort and F.d herelle
• Some viruses infect bacteria called bacteriophage
W. Stanley in 1935
• Demonstrate the structure of plant virus that was Tobacco Mosaic Virus
(TMV)
6. Viral Properties/ Characteristics
• Viruses are inert (nucleoprotein ) filterable
agents
• Viruses are obligate intracellular parasites
• Viruses cannot make energy or proteins
independent of a host cell
• Viral genome are RNA or DNA but not both.
• Viruses have a naked capsid or envelope with
attached lipoproteins
• Viruses do not have the genetic capability to
multiply by division.
• Viruses are non-living entities
7. Consequences of Viral Properties
• Viruses are non living out side the cell
• Viruses are disease causing agent
• Viruses must be able to use host cell processes to
produce their components (viral messenger RNA,
protein, and identical copies of the genome)
• Viral components must self-assemble
• The fully assembled infective particle is called
Virion.
8. Challenges the way we define life
• viruses do not respire,
• they do not move
• they do not grow
• they do most certainly reproduce, and may adapt
to new hosts.
9. Types Of Viruses
Animal viruses:
• cause disease in man and animals.
• Contain DNA core covered by capsid.
Plant viruses:
•cause disease in plants.
•Contain RNA core covered by
protective protein.
10. TypesOf Viruses
Retroviruses:
• cause disease in humans
• containing RNA as genetic material.
Gemini viruses:
• cause disease in plants.
• Contain ss-DNA as genetic material
28. Viral core
• Viral core
The viral nucleic acid genome, In the
center of the virus.
Control the viral heredity and variation,
responsible for the infectivity.
29. Genome
• The genome of a virus can be either DNA or RNA
• DNA-double stranded (ds): linear or circular
Single stranded (ss) : linear or circular
• RNA- ss: segmented or non-segmented
ds: linear (only reovirus family)-not circular
32. Viral Capsid
• The protein shell, or coat, that encloses
the nucleic acid genome.
• Functions:
• a. Protect the viral nucleic acid.
• b. Participate in the viral infection.
• c. Share the antigenicity
33. Nucleocapsid
•The core of a virus particle
consisting of the genome plus
a complex of proteins.
• complex of proteins = Structural proteins
+Non- Structural proteins (Enzymes &
Nucleic acid binding proteins)
38. Cubicor icosahedral symmetry
• Cubic or icosahedral symmetry
• Identical 20 triangularunits arranged in cluster of five or
six, 12 corner and 30 edges
• covered with capsomeres
• Mostly spherical shaped
• Including animal virus
42. Example of Icosahedral
1. Adenovirus
2. Hepatitis Virus
Hepatitis A Virus (HAV)
Hepatitis B Virus (HBV)
Hepatitis C Virus (HCV)
Hepatitis Delta Virus (HDV)
Hepatitis E Virus (HEV)
3. Herpes Virus
Herpes Simplex Virus 1 (HHV1)
Herpes Simplex Virus 2 (HHV2)
4. Human Immunodeficiency
Virus (HIV)
5. Human T-lymphotrophic
Virus (HTLV)
6. Polio virus
7. Rhinovirus
8. Rubella Virus
43. Complex Virus Structures
• Uncertain symmetry
• Proteins and lipoproteins
• A well known example is the tailed
bacteriophages.
• The head of these viruses is cubic with
a triangulation number of 7. This is
attached by a collar to a contractile tail
with base plate and tail fibril
48. Properties of naked viruses
• Stable in hostile environment
• Not damaged by drying, acid, detergent, and heat
• Released by lysis of host cells
• Can sustain in dry environment
• Can infect the GI (gastrointestinal tract) and
survive in the acid condition
• Can spread easily via hands, dust, fomites, etc
• Can stay dry and still retain infectivity
• Neutralizing mucosal and systemic antibodies are
needed to control the establishment of infection
49. Naked viruses( Non Enveloped )
Example
Hepatitis A Virus (HAV)
Hepatitis E Virus (HEV)
52. Envelope
•A lipid-containing membrane that
surrounds some viral particles.
• It is acquired during viral maturation by a
budding process through a cellular
membrane, Viruses-encoded glycoproteins
are exposed on the surface of the envelope.
• Not all viruses have the envelope, and
viruses can be divided into 2 kinds:
enveloped virus and naked virus.
53. Functions of envelope
• Antigenicity
some viruses possess
neuraminidase (The enzyme helps
viruses to be released from a host
cell).
• Infectivity
• Resistance
54.
55. Properties of enveloped viruses
• Labile in dry , arid environment
• Damaged by drying, acid, detergent,
and heat
• Pick up new cell membrane during
multiplication
• Insert new virus-specific proteins after
assembly
• Virus is released by budding
56. Consequences of Properties for
enveloped viruses
• Must stay moist
• Must not infect the GI tract for survival
• Must be transmitted by droplets, secretions,
blood and body fluids
• Must re-infect another host cell to sustain
• Humoral and cell-mediated immunity are
needed to control the infection
59. Spike or Peplomer
A peplomer is a glycoprotein spike on a viral capsid or
viral envelope. These protrusions will only bind to certain
receptors on the host cell, they are essential for viral
infectivity.
62. Viroids
•Viroids are small (200-400nt), circular
RNA molecules with a rod-like
secondary structure which possess no
capsid or envelope which are associated
with certain plant diseases. Their
replication strategy like that of viruses -
they are obligate intracellular parasites.
63. Viroids
• Viroids are small (200-400nt), circular RNA
molecules with a rod-like secondary structure
which possess no capsid or envelope which are
associated with certain plant diseases. Their
replication strategy like that of viruses - they are
obligate intracellular parasites.
64. (Prions)
• Prions are rather ill-defined infectious agents
believed to consist of a single type of protein
molecule with no nucleic acid component.
Confusion arises from the fact that the prion
protein & the gene which encodes it are also found
in normal 'uninfected' cells. These agents are
associated with diseases such as Creutzfeldt-Jakob
disease in humans, scrapie in sheep & bovine
spongiform encephalopathy (BSE) in cattle.
Editor's Notes
Humoral Immunity - this involves the use of antibodies produced by the b cells to attack any invading foreign bodies like bacteria, viruses etc. Production of memory cells also takes place for a faster response in case of a second infection.Cell mediated immunity- this involves the destruction of self cells damaged by mutations or infected by viruses. this form of immunity includes cells like cytotoxic t cells nk cells.