B and T cells
- A small study conducted on 71 individuals who received two doses of Covaxin found that the vaccine generates antibodies and easily detectable memory B cell and T cell responses in many recipients.
- The cellular immune responses in the form of memory B cells and memory T cells seen in most vaccinated people would mean that the immune system can respond swiftly and provide protection in case of a breakthrough infection.
- Cellular immunity is mediated by T lymphocytes, also called T cells. Their name refers to the organ from which they’re produced: the thymus.
- This type of immunity promotes the destruction of microbes residing in or the killing of infected cells to eliminate reservoirs of infection.
- When infected by a virus, non-specific immune response in the form of macrophages, neutrophils and other cells tend to prevent the virus from causing symptoms.
- Soon after, the body makes antibodies specific to the virus called the immunoglobulins IgG and IgM, called the adaptive response.
- In addition, the cellular immunity kicks in when the body makes T cells that destroy cells that have been infected by the virus.
- The combination of adaptive response and cellular immunity “may prevent progression to severe illness or reinfection by the same virus. This process is often measured by the presence of antibodies in blood.
- Both T cells and B cells are produced in the bone marrow. The T cells migrate to the thymus for maturation.
- The main difference between T cells and B cells is that T cells can only recognize viral antigens outside the infected cells whereas B cells can recognize the surface antigens of bacteria and viruses.
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Gene and non-communicable disease
- Evolution is a process of natural selection in which traits that improve the fitness of the organism to survive the challenges posed by its surrounding environment.
- However, genes have multiple effects: The very same genes that are responsible for improving an aspect of the fitness of the organism may have other contributions too, such as increasing the risk for a non-communicable disease.
- A paper published recently in Scientific Reports shows that this may be the case also with some severe mental illnesses, like schizophrenia and bipolar disorder.
- Sequencing the exome means sequencing this, relatively small, portion of the genome, which codes for proteins.
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Evolution through layers of food chain
- Scientists now understand how certain animals can feed on picturesque, orange monarch butterflies, which are filled from head to abdomen with milkweed plant toxins.
- Milkweed produces toxic cardiac glycosides that can kill a horse, or a human, if consumed in high-enough concentration. However, monarch butterflies have evolved a set of unusual cellular mutations to be able to eat this plant.
- Now, a study carried out by researchers at the University of California, Riverside shows that the animals that prey on monarch butterflies too have evolved these same mutations.
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Horses in ancient India
- A recent report in Nature by Ludovic Orlando and his group from the Paul Sabatier University in Toulose, France (P. Librado et al., Nature 598, 636-642; 2021) has been able to collect bones and teeth samples of over 2,000 such ancient specimens from regions from where domestic horses could have originated, namely in the Iberian Peninsula in the southwestern corner of Europe, or the western-most edge of Eurasia (Spain and its neighbours), Anatolia (which is modern Turkey), and the steppes of Western Eurasia and Central Asia.
- A similar genetic analysis has also found that horses with the modern domestic DNA profile lived in the Western Eurasian Steppes, particularly the Volga-Don River region. By around 2200–2000 BCE, these horses spread out to Bohemia (the Czech Republic of today and Ukraine), and Central Asia (Kazhakstan, Kyrgystan, Tajikistan, Turkmenistan and Uzbekistan, Iran and Afghanistan) and Mongolia.
- These horses were bred by breeders from these countries to sell them to countries that demanded them.
- Riding on horses became popular in these nations by around 3300 BCE, and armies were built using them, for example, in Mesopotamia, Iran, Kuwait.
- The “World Atlas” says that the only animals native to India are the Asian elephant, snow leopard, rhinoceros, Bengal tiger, Sloth bear, Himalayan wolf, Gaur bison, red panda, crocodile, and the birds peacock and flamingo.
- The website ThoughtCo cites, in the article ‘11 domestic animals that originated in Asia’, lists the antelope, Nilgiri tahr, elephant, langur, Macaque monkey, rhinoceros, dolphin, Gharial crocodile, leopard, bear, tiger, bustard (heaviest flying bird), squirrel, cobra, and peacock.
- Thus, it seems clear from these sources that horse is not native to India.
- Horses must have come into India through inter-regional trading between countries. Indians might have traded their elephants, tigers, monkeys, birds to their neighbours and imported horses for our use.
- Wikipedia points out that horse-related remains and artefacts have been found in Late Harappan sites (1900-1300 BCE), and that horses did not seem to have played an essential role in the Harappan civilization.
- This is in contrast to the Vedic Period, which is a little later (1500-500 BCE). (The Sanskrit word for horse is Ashwa, which is mentioned in the Vedas and Hindu Scriptures).
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Space industry and biosecurity
- Scientists have drawn attention to biosecurity risks due to the space industry.
- An article in Biosciences reveals how humans have spread organisms to remote regions of the Earth and also perhaps space, and while probability of an alien organism surviving a space journey is low, it is not zero.
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Omicron variant
- First, seroprevalence studies indicate that a large proportion of the population has already been exposed to the virus providing some level of protection to subsequent infections.
- Second, the immunization campaign has gained momentum.
- Approximately 44% of Indian adults have been fully vaccinated and 82% have received at least one dose.
- A new variant of the SARS-CoV-2 virus was recently identified in Botswana.
- Called the Omicron variant, early evidence suggests that it may be responsible for the steep rise of cases.
- When new variants can evade immunity obtained through immunization and prior infections, there is a greater chance for breakthrough cases and further transmission.
- Viruses mutate all the time and SARS-CoV-2 is no exception.
- What is unusual is the very large number of mutations that the Omicron variant has accumulated.
- A strong immune response can ultimately eliminate the virus. However, in a weakened immune system the virus will continue to multiply and mutate, changing its form to evade immune response.
- Vaccination is an especially powerful tool.
- Even a single dose of vaccine can reduce dramatically the risk of hospitalization or a worse outcome; two doses do even better.
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Earthquake in Peru
- An earthquake with a preliminary magnitude of 7.5 struck northern Peru
- Earthquakes in Peru are common occurrences as the country is located in a seismic zone.
- The interface between the Nazca and South American tectonic plates is located near the Peruvian coast. The South American Plate is moving over the Nazca Plate at a rate of 77 mm (3.0 in) per year.
- Thus, earthquakes occur as thrust faulting (A thrust fault is a break in the Earth’s crust, across which older rocks are pushed above younger rocks).on the interface between the two plates, with the South American Plate moving towards the sea over the Nazca Plate.
- The same process has caused the rise of the Andes mountain range and the creation of the Peru–Chile Trench, as well as volcanism in the Peruvian highlands.
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