The human immunodeficiency virus (HIV) is a lentivirus (a subgroup of retrovirus) that causes HIV infection and over time acquired immunodeficiency syndrome (AIDS).
The human immunodeficiency virus (HIV) is a lentivirus (a subgroup of retrovirus) that causes HIV infection and over time acquired immunodeficiency syndrome (AIDS).
The hepatitis B virion (Dane particle):
outer lipid envelope with the surface antigen (HBsAg).
an electron-dense core (nucleocapsid): ds circular DNA and polymerase surrounded by the core antigen (HBcAg).
The HBsAg is produced in excess by the infected hepatocytes and is secreted in the form of spherical
and filamentous particles.
A serious liver infection caused by the hepatitis B virus that's easily preventable by a vaccine.
This disease is most commonly spread by exposure to infected bodily fluids.
Symptoms are variable and include yellowing of the eyes, abdominal pain and dark urine. Some people, particularly children, don't experience any symptoms. In chronic cases, liver failure, cancer or scarring can occur.
The condition often clears up on its own. Chronic cases require medication and possibly a liver transplant.
An enzyme is a substance that acts as a catalyst in living organisms, regulating the rate at which chemical reactions proceed without itself being altered in the process. The biological processes that occur within all living organisms are chemical reactions, and most are regulated by enzymes
The aqueous humour is a transparent, watery fluid similar to plasma, but containing low protein concentrations. It is secreted from the ciliary epithelium, a structure supporting the lens
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. The cornea, with the anterior chamber and lens, refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power.
Lens is a transparent, biconvex, crystalline structure placed between iris and the vitreous in a saucer-shaped depression, the patellar fossa. The lens is a crystalline structure that is avascular and is devoid of nerves and connective tissue
It consists of three distinct part:
Lens capsule
Anterior lens epithelium, and
Lens substance or lens fibres
Small amounts of vitamins are required in the diet to promote growth, reproduction, and health. Vitamins A, D, E, and K are called the fat-soluble vitamins, because they are soluble in organic solvents and are absorbed and transported in a manner similar to that of fats.
Water soluble vitamins include Vitamin C and the vitamin B complex: thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), Vitamin B6, biotin (B7), folic acid (B9), Vitamin B12. Vitamin A in its Beta-Carotene form is also water-soluble.
The tear film is a complex mixture of substances secreted from multiple sources on the ocular surface, including the lacrimal gland, the accessory lacrimal glands, the meibomian glands, and the goblet cells.
A picornavirus is a virus belonging to the family Picornaviridae, a family of viruses in the order Picornavirales. Vertebrates, including humans, serve as natural hosts. Picornaviruses are nonenveloped viruses that represent a large family of small, cytoplasmic, plus-strand RNA viruses with a 30-nm icosahedral capsid.
Poxviruses are brick or oval-shaped viruses with large double-stranded DNA genomes. Poxviruses exist throughout the world and cause disease in humans and many other types of animals. Poxvirus infections typically result in the formation of lesions, skin nodules, or disseminated rash.
Leptospirosis is a bacterial disease that affects humans and animals. It is caused by bacteria of the genus Leptospira. In humans, it can cause a wide range of symptoms, some of which may be mistaken for other diseases. Some infected persons, however, may have no symptoms at all.
Treponema is a genus of spiral-shaped bacteria. The major treponeme species of human pathogens is Treponema pallidum, whose subspecies are responsible for diseases such as syphilis, bejel, and yaws.
Haemophilus is the name of a group of bacteria. There are several types of Haemophilus. They can cause different types of illnesses involving breathing, bones and joints, and the nervous system. One common type, Hib (Haemophilus influenzae type b), causes serious disease. It usually strikes children under 5 years old
Moraxella is a genus of Gram-negative bacteria in the Moraxellaceae family. It is named after the Swiss ophthalmologist Victor Morax. The organisms are short rods, coccobacilli, or as in the case of Moraxella catarrhalis, diplococci in morphology, with asaccharolytic, oxidase-positive, and catalase-positive properties
Pseudomonas is a type of bacteria that can cause infections. Pseudomonas is a common genus of bacteria, which can create infections in the body under certain circumstances. There are many different types of Pseudomonas bacteria
Neisseria gonorrhoeae is the obligate human pathogen that causes the sexually transmitted disease (STD) gonorrhea. This Gram-negative diplococci/gonococci does not infect other animals or experimental animals and does not survive freely in the environment. The gonococcal infection occurs in the upper or lower tract, pharynx, ophthalmic area, rectum, and bloodstream. During the 1980’s gonorrhea was also referred to as “the clap” when public awareness was quite minimal. This was one of the venereal diseases prostitutes hoped to contract since it resulted in infertility by pelvic inflammatory disease (PID). As documentation, diagnostic testing, and public awareness improved, there has been a decline in incidence reports, however, it is still considered a very common infectious disease.
Meningococci are a type of bacteria that cause serious infections. The most common infection is meningitis, which is an inflammation of the thin tissue that surrounds the brain and spinal cord. Meningococci can also cause other problems, including a serious bloodstream infection called sepsis. In its early stages, you may have flu-like symptoms and a stiff neck. But the disease can progress quickly and can be fatal. Early diagnosis and treatment are extremely important. Lab tests on your blood and cerebrospinal fluid can tell if you have it. Treatment is with antibiotics. Since the infection spreads from person to person, family members may also need to be treated.
A vaccine can prevent meningococcal infections.
Diphtheria is an infection caused by the bacterium Corynebacterium diphtheriae. Diphtheria causes a thick covering in the back of the throat. It can lead to difficulty breathing, heart failure, paralysis, and even death. CDC recommends vaccines for infants, children, teens and adults to prevent diphtheria. The presentation consists of basic concepts regarding the bacteria and its infection. It has explanation in detail about signs and symptoms of Diptheria
Contraindications, Adverse reactions and ocular nutritional supplementsArun Geetha Viswanathan
utritional supplements comprise a great deal of the products available over the counter in most pharmacies. Although most vitamin supplements are relatively harmless—except for the fat soluble ones A, D, E, and K—they are not the only supplements available to patients. Some of these other, non-vitamin supplements can actually be harmful to patients and often they have been proven to be ineffective. This doesn’t mean that patients will stop taking them though, which in turn leaves the potential for contraindications of nutritional supplements with prescription-based drugs wide open.
Ageing is a gradual process that takes place over many decades. Most theories of ageing relate to impaired DNA replication and loss of cell viability and hence the viability of the body’s organs. Ageing is often accompanied by socioeconomic changes that can have a great impact on the nutritional needs and status of elderly individuals. The incidence of disability increases with ageing, with over a third of the elderly population limited by chronic conditions and unable to carry on normal daily living activity
Every component of the eye is vulnerable to damage from ROI, particularly retina. There are several reasons for the vulnerability of the retina, including high concentrations of polyunsaturated fatty acid (PUFA), constant exposure to visible light, high consumption of oxygen, an abundance of photosensitisers in the neurosensory retina and the RPE, the process of phagocytosis by the RPE which is known to generate hydrogen peroxide.
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.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Richard's aventures in two entangled wonderlandsRichard 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.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
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.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
1. Hepatitis
B virus
A double stranded DNA virus, a
species of the genus
Orthohepadnavirus, and a
member of the Hepadnaviridae
family of viruses. This virus
causes the disease hepatitis B.
Included in oncogenic viruses
Attribution-NonCommercial-ShareAlike
4.0 International (CC BY-NC-SA 4.0)
2. The oldest
virus ever
found is
an STI
An international team of
scientists led by researchers at
the Max Planck Institute for the
Science of Human History and
the University of Kiel has
successfully reconstructed
genomes from Stone Age and
Medieval European strains of
the hepatitis B virus.
This unprecedented recovery of
ancient virus DNA indicates that
hepatitis B was circulating in
Europe at least 7000 years ago.
While the ancient virus is
similar to its modern
counterparts, the strains
represent a distinct lineage that
has likely gone extinct and is
most closely related to
chimpanzee and gorilla viruses.
May 10, 2018,
Source: Max Planck Institute for the Science of Human History
4. Structure
• HBV a member of the hepadnavirus group
• double-stranded DNA viruses which replicate by
reverse transcription.
• 42-nm in size
• HBV express three main antigens:
1. HBsAg
2. HBcAg
3. HBeAg
• These antigens are recognized by antibody proteins
that bind specifically to one of these surface proteins
5. Structure/HBsAg
• Nucleocapsid is 27 nm in diameter surrounded by an
outer envelope of the surface protein (HBsAg)
embedded in membranous lipid derived from the
host cell
• also known as the Australia antigen. It indicates
current hepatitis B infection.
• Positive HBsAg tests can be due to recent vaccination
against HBV but this positivity is unlikely to persist
beyond 14 days post-vaccination
• It is present in the sera of patients with viral hepatitis
B (with or without clinical symptoms).
6. Structure/HBcAg
• HBcAg (core antigen) is a hepatitis B viral protein.
• It is an indicator of active viral replication
• This means the person infected with Hepatitis B can
likely transmit the virus on to another person.
• HBcAg is not secreted. HBcAg is considered
"particulate" and it does not circulate in the blood.
• it is readily detected in hepatocytes after biopsy
• The presence of both HBcAg and HBeAg proteins
together act as a marker of viral replication, and
antibodies to these antigens are a marker of
declining replication.
7. Structure/HBeAg
• It is an indicator of active viral replication; this means
the person infected with Hepatitis B can likely
transmit the virus on to another person.
• can be found between the icosahedral nucleocapsid
core and the lipid envelope
• HBeAg is considered "nonparticulate" or "secretory".
• HBeAg is secreted and accumulates in serum as an
immunologically distinct soluble antigen.
• The presence of HBeAg in the serum of patients can
serve as a marker of active replication in chronic
hepatitis.
9. Multiplication
• one of a few known non-retroviral viruses which use reverse
transcription
• The virus gains entry into the cell by binding to receptors on
the surface of the cell and entering it by endocytosis mediated
by either clathrin or caveolin-1.
• HBV initially binds to heparin sulfate proteoglycan
• Following endocytosis, the virus membrane fuses with the
host cell's membrane, releasing the nucleocapsid into the
cytoplasm
10. Multiplication
• the viral genomic DNA has to be transferred to the cell nucleus.
• The core proteins dissociate from the partially double stranded viral
DNA, which is then made fully double stranded (by host DNA
polymerases) and transformed into covalently closed circular DNA
(cccDNA) that serves as a template for transcription of four viral
mRNAs.
• The largest mRNA, (which is longer than the viral genome), is used
to make the new copies of the genome and to make the capsid core
protein and the viral RNA-dependant-DNA-polymerase.
11. Hepatitis B
• Hepatitis B is an infectious disease caused by HBV that
affects the liver. It can cause both acute and chronic
infections.
• The virus may be detected within 30 to 60 days after
infection and can persist and develop into chronic
hepatitis B.
• The incubation period of the hepatitis B virus is 75 days
on average but can vary from 30 to 180 days.
12. Pathogenesis
• Hepatitis B virus primarily interferes with the functions of the
liver by replicating in hepatocytes.
• virions bind to the host cell via the viral surface antigen and
are subsequently internalized by endocytosis. HBV specific
receptors are expressed primarily on hepatocytes
• During HBV infection, the host immune response causes both
hepatocellular damage and viral clearance.
• Most liver injury is caused by cytotoxic T lymphocytes
13. Pathogenesis/Cancer
• HBV causes hepatocellular carcinoma
• An HBV protein traps protons and Cl−, and induces the expression of
collagen in the liver, which forms potent hydrogen bonds with
trapped protons.
• The presence of collagen in the liver marks the progression to
fibrosis.
• Virus can cause inactivation tumor suppressor genes, or activation
of oncogenic genes like cyclin A
• Translocation and chromosomal arrangements also have been seen
14. Symptoms
Acute Infection
• Symptoms of acute HBV infection are non-specific and include fatigue,
poor appetite, nausea, vomiting, abdominal pain, low-grade fever,
jaundice, and dark urine.
• itchy skin is a possible symptom of all hepatitis virus types
• liver tenderness, hepatomegaly, and splenomegaly
• it can lead to fulminant hepatic failure and may die or require emergent
liver transplantation.
• The infection may be entirely asymptomatic and may go unrecognized
15. Symptoms
Chronic Infection
• HBV infection is considered chronic when it persists longer than six months
• asymptomatic or may be associated with a chronic inflammation of the liver – Chronic
hepatitis
• Coinfection with human immunodeficiency virus (HIV) or hepatitis C virus can occur
• It can lead to liver cirrhosis
• increases the incidence of hepatocellular carcinoma (HCC; liver cancer)
• Acute necrotizing vasculitis, glomerulonephritis, jaundice, fever, skin rash, and
polyarteritis.
• Nephropathy, anemia
16. Transmission
• exposure to infectious blood or body fluids containing blood
• Possible forms of transmission include sexual contact and blood
transfusions
• re-use of contaminated needles and syringes and vertical
transmission from mother to child during childbirth
• can be transmitted between family members within households,
possibly by contact of non-intact skin or mucous membrane with
secretions or saliva containing HBV
17. Diagnosis
• evaluation of the patient's blood for
• HBsAg
• hepatitis B surface antibody (HBsAb)
• hepatitis B core antibody (HBcAb)
• presence of HBsAg indicates that the person is infectious
• presence of HBsAb indicates recovery and immunity from HBV
infection or successful immunization against HBV.
• HBcAb appears at the onset of acute HBV infection, but may
also indicate chronic HBV infection.
18. Diagnosis
Serum transaminases
• Once an individual has been diagnosed with chronic
HBV infection, follow-up testing must be performed
for alanine aminotransferase (ALT), a marker of liver
cell inflammation
HBV-DNA
• The presence of HBV-DNA in serum or plasma
denotes active HBV infection and, depending on the
viral load, correlates with the infectivity of the
patient.
19. Prevention
Vaccines
• Most vaccines are given in three doses over a course
of months
• The first dose is recommended within 24 hours of
birth with either two or three more doses given after
that
• For newborns of HBsAg-positive mothers: the
combination of vaccine plus hepatitis B
immunoglobulin is superior to vaccine alone
• Tenofovir given in the second or third trimester can
reduce the risk of mother to child transmission
• it is now believed that the hepatitis B vaccine
provides indefinite protection.
20. Treatment
• none of the available drugs can clear the infection
but can reduce virus load
• These include antiviral drugs
• lamivudine (Epivir)
• adefovir (Hepsera)
• tenofovir (Viread)
• telbivudine (Tyzeka)
• entecavir (Baraclude)
• the two immune system modulators
• interferon alpha-2a
• PEGylated interferon alpha-2a (Pegasys).