Daily Prelims Notes 7 May 2024
- May 7, 2024
- Posted by: OptimizeIAS Team
- Category: DPN
Daily Prelims Notes
7 May 2024
1. A mouth bacteria has starring role in colorectal cancer: study
Subject: Science and tech
Sec: Health
Context:
- Recent research by the Fred Hutchinson Cancer Center in the U.S. has discovered a specific subtype of the bacterium ‘Fusobacterium nucleatum’ that is more prevalent in colorectal cancer (CRC) tumours.
Details:
- This subtype’s genetic characteristics may enhance its association with gut cancers.
- In experiments, mice infected with this subtype developed precancerous intestinal growths known as adenomas.
- These findings, pointing to a potential role of Fusobacterium in CRC progression, could lead to new diagnostic and treatment strategies for CRC, which is increasingly prevalent globally and notably among younger populations.
- CRC is the seventh most common type of cancer in India, where the number of cases rose by 20% from 2004 to 2014. Worldwide, the overall CRC incidence has declined but the incidence of age-adjusted early-onset CRC “has risen at an alarming rate of 2-4% in many countries, with even sharper increases in individuals younger than 30 years.”
About Fusobacterium nucleatum:
- Fusobacterium nucleatum, typically found in the human mouth, has been linked to colorectal cancer (CRC) by promoting cancer cell evasion from the immune system.
- Researchers cultured Fusobacterium bacteria from 130 human colorectal cancer (CRC) tumours and conducted a full genetic analysis.
- They discovered that among the four known subspecies of Fusobacterium nucleatum, only Fusobacterium nucleatumanimalis (Fna) was significantly linked to CRC tumours.
- Pangenomic analysis, which maps all genes of a species including its accessory genome (genes not shared by all members), showed that Fna has a notably small core genome, suggesting diverse subtypes within Fna.
- Further genetic tracing revealed that Fna consists of two distinct evolutionary lineages, referred to as clades.
- These clades, named Fna C1 and Fna C2, were examined, with Fna C2 found to be significantly associated with CRC tumours and possessing additional genetic features that may enhance this association.
- This differentiation into clades highlights the complex relationship between Fusobacterium nucleatum subtypes and their role in colorectal cancer.
Colonising the gut:
- The study identified physical and genetic distinctions between two clades of Fusobacterium nucleatumanimalis (Fna) which contribute to their association with colorectal cancer (CRC) tumors.
- The Fna C2 bacteria, physically longer and thinner than Fna C1, possess unique genes enabling them to utilize ethanolamine and 1,2-propanediol for energy in the gut, traits not found in Fna C1. This enhanced metabolic capability likely aids their survival and association with CRC tumours.
- Further evidence of Fna C2’s adaptation to the gut environment was found in an analysis of over 1,200 human stool samples, where genes necessary for metabolizing these compounds were more prevalent in samples from CRC patients compared to healthy individuals.
- The study also proposed a new pathway for these bacteria to travel from the mouth to the gut, suggesting they can survive the journey through the highly acidic stomach environment, unlike other bacteria.
- Fna C2 has evolved acid-resistant genes that activate in acidic conditions, enabling their survival and colonisation in the gut, contrasting with the previously assumed route of bloodstream infection during oral injuries or procedures.
Impact of the Fusobacterium nucleatumanimalis (Fna) C2 bacteria:
- The research investigated the impact of Fusobacterium nucleatumanimalis (Fna) C2 bacteria on tumour development by introducing them into the inflamed guts of mice, which led to a higher incidence of adenomas compared to mice treated with Fna C1.
- The metabolic profiles of Fna C2-treated mice also indicated changes that support tumour progression, affirming Fna C2‘s unique ability to alter the intestinal environment in ways conducive to colorectal cancer (CRC).
- Further validation in human patients showed that Fna C2 was predominantly found in CRC tissues and stool samples of CRC patients, but not in non-cancerous samples or those from healthy individuals. This specificity suggests potential for Fna C2 as a marker for CRC detection.
- Experts see the study as a promising step towards microbial cellular therapies for cancer and targeted microbial interventions for CRC.
- The findings encourage future research into tracking microbial changes in high-risk individuals to better understand the interactions between specific bacterial strains and cancer development.
- Challenges remain, including the development of treatments that can selectively target harmful bacteria like Fna C2 without disrupting other beneficial gut bacteria.
Source: TH
Subject: Environment
Sec: Climate Change
Carbon Farming:
- Carbon farming integrates the fundamental role of carbon in life processes with agricultural practices, focusing on regenerative techniques that enhance ecosystem health, improve soil health, and boost agricultural productivity.
- This approach helps mitigate climate change by increasing carbon storage in soil and reducing greenhouse gas emissions.
- It is adaptable to various agro-climatic conditions and offers solutions to issues like soil degradation, water scarcity, and climate variability.
- The technical term for this is carbon sequestration.
Carbon farming techniques:
- Carbon farming employs various sustainable agricultural practices to enhance carbon sequestration, improve soil health, and reduce greenhouse gas emissions.
- Techniques such as rotational grazing, agroforestry, conservation agriculture, and integrated nutrient management each contribute differently.
- Agroforestry (including silvopasture and alley cropping) increases carbon storage in vegetation, while conservation agriculture reduces soil disturbance and increases organic content.
- Integrated nutrient management optimizes the use of organic fertilizers to promote soil fertility and reduce emissions.
- Additionally, strategies in livestock management help lower methane emissions and enhance carbon storage in pastures.
- Collectively, these practices not only contribute to mitigating climate change but also support diverse and resilient agricultural ecosystems.
Challenges:
- Carbon farming offers significant benefits but faces several challenges that affect its effectiveness, including geographical variations, soil types, crop selection, water availability, biodiversity, and the scale of farming operations.
- Its success is also dependent on effective land management, supportive policies, and active community involvement.
- Regions with long growing seasons, ample rainfall, and good irrigation systems are more conducive to carbon farming due to better conditions for vegetation growth and carbon sequestration.
- Techniques like agroforestry and conservation agriculture have high potential in such fertile and well-watered areas.
- Conversely, carbon farming is more challenging in arid regions with limited water availability, where water is prioritized for essential uses over agricultural expansion.
- This scarcity can limit plant growth, essential for carbon sequestration through photosynthesis.
- Additionally, the choice of plant species is critical, as not all are equally effective at trapping and storing carbon, and some may not thrive in dry conditions.
- Economic factors also play a role, particularly in developing countries where small-scale farmers may lack the resources to implement sustainable practices without financial support.
Global scenario:
- Carbon farming has gained traction worldwide with schemes such as carbon trading in the agriculture sector, particularly in countries like the U.S., Australia, New Zealand, and Canada where voluntary carbon markets are prominent.
- Examples include the Chicago Climate Exchange and Australia’s Carbon Farming Initiative, which encourage practices like no-till farming and reforestation to reduce carbon emissions and enhance carbon sequestration in agriculture.
- Internationally, projects like Kenya’s Agricultural Carbon Project, supported by the World Bank, demonstrate carbon farming’s potential to address climate change mitigation, adaptation, and food security in developing regions.
- Additionally, the ‘4 per 1000’ initiative launched during the COP21 climate talks in 2015 in Paris emphasizes the critical role of carbon sinks in mitigating greenhouse gas emissions.
Indian scenario:
- Organic and agro-ecological farming practices have demonstrated the potential to sequester carbon, with the possibility of creating an economic value of approximately $63 billion across India’s 170 million hectares of arable land.
- This includes incentives for farmers, offering them about ₹5,000-6,000 per acre annually for providing climate services through sustainable agriculture.
- Regions like the Indo-Gangetic plains and the Deccan Plateau are well positioned for carbon farming, whereas the Himalayan and coastal areas face challenges due to their terrain and salinisation, respectively.
- Additionally, implementing carbon credit systems could provide farmers with supplementary income by monetizing the environmental services of carbon sequestration.
- Research suggests that agricultural soils could absorb 3-8 billion tonnes of CO2 equivalent annually over 20-30 years, significantly aiding in climate stabilization and bridging the gap in necessary emissions reductions.
- However, scaling up carbon farming in India requires overcoming hurdles such as limited awareness, insufficient policy frameworks, technological limitations, and creating an environment conducive to adoption.
- Despite these challenges, promoting carbon farming aligns with India’s interests to combat climate change, enhance soil health, boost biodiversity, and generate economic benefits for farmers.
Source: TH
3. Understanding the science behind magnetic resonance imaging
Subject: Science and tech
Sec: Health
Context:
- Magnetic resonance imaging (MRI) is a critical non-invasive tool for examining the internal structures of the human body.
- The foundational techniques of MRI were developed in the early 1970s, with significant advancements made later that decade by Paul Lauterbur and Peter Mansfield, who refined the technology for commercial application.
- Their contributions were recognized with the Nobel Prize in Medicine in 2003, underscoring the importance of MRI in contemporary medical diagnostics.
What is Magnetic resonance imaging (MRI)?
- MRI is a non-invasive diagnostic tool that uses strong magnetic fields to create detailed images of soft tissues within the body, such as the brain, cardiovascular system, spinal cord, joints, muscles, liver, and arteries.
- It is particularly useful for observing and treating certain cancers like prostate and rectal cancer, as well as monitoring neurological conditions such as Alzheimer’s, dementia, epilepsy, and stroke.
- Functional MRI (fMRI) is a variation used to study brain activity by measuring changes in blood flow.
- However, the use of strong magnetic fields means that individuals with metallic implants or embedded metallic objects, like shrapnel or pacemakers, may not be able to undergo MRI scans due to safety concerns. Additionally, these magnetic fields can demagnetize credit cards if carried close to the scanner.
Working of MRI:
- MRI works by using the natural abundance of hydrogen atoms found in fat and water throughout the body to generate detailed images.
- The procedure involves four key components within an MRI machine.
- Superconducting Magnet: This is the primary component that creates a powerful and stable magnetic field around the body part being examined. It aligns the spinning hydrogen atoms in the body, such that their spin axes point along the direction of the magnetic field.
- Radiofrequency Pulse Emitter: This device emits pulses that specifically target a small population of ‘excess’ hydrogen atoms (those whose alignment is slightly off due to natural variances among approximately a million atoms). These excess atoms absorb the radiofrequency energy and become excited.
- Detector: When the radiofrequency pulse is turned off, the excited hydrogen atoms release the absorbed energy as they return to their lower energy state. This released energy is detected as emissions.
- Computer System: The emissions collected by the detector are converted into signals that a computer processes to construct two- or three-dimensional images of the scanned body part.
- The entire process is non-invasive and particularly useful for imaging soft tissues in the human body.
- The strength of the magnetic field and the nature of the tissue influence the specific radiofrequency (known as the Larmor frequency) needed to excite the hydrogen atoms.
Pros of MRI | Cons of MRI |
Precision and Flexibility:
Comprehensive Imaging:
Tissue Differentiation:
Safety:
| High Cost:
Patient Discomfort:
Energy Intensity:
Noise:
|
Source: TH
4. Why is the launch of Boeing’s Starliner significant?
Subject: Science and tech
Sec: Space
Context:
- Boeing’s Starliner spacecraft, carrying two NASA astronauts, will be launched by an Atlas V rocket from the Kennedy Space Center in Cape Canaveral, Florida, to the International Space Station (ISS) on Tuesday.
More on news:
- This will be Starliner’s first crewed test flight.
- If the mission is successful, Boeing will become the second private firm to be able to provide NASA crew transport to and from the ISS, alongside Elon Musk’s SpaceX.
What is Boeing’s Starliner?
- Starliner is a partially reusable crew capsule, officially known as CST-100 (crew space transportation).
- The capsule, which is 5 m tall and 4.6 m wide, consists of two modules.
- It includes a crew capsule, where astronauts reside and which can withstand reentry to Earth, and a service module equipped with life support systems and engines.
- It is more than 4 m wide and can house up to seven astronauts.
- It can be fitted atop an Atlas V rocket.
- The crew module can be reused up to 10 times, with a six-month turnaround.
What is the mission?
- The main objective of the mission is to see how Starliner performs in space with a crew onboard.
- It is supposed to dock with the ISS — a day after the launch — for around 10 days before it returns to the Earth.
- The crew members will test flying it manually.
- The crew will also test seats, assess onboard life-support and navigation systems, as well as evaluate the system that moves cargo into the ISS.
- The space suits will also be tested as these blue suits are around 40% lighter than their predecessors and have touchscreen-sensitive gloves.
- During the return journey, NASA and Boeing will be keeping an eye on the spacecraft’s heat shield and parachutes.
- They will slow the descent before airbags open to soften the moment of impact with the ground — unlike other crew capsules, Starliner will land on the ground and not in the sea.
Why is the mission significant?
- The mission’s success is crucial for both NASA and Boeing.
- Currently, NASA has only one private company, SpaceX, which can take its astronauts and cargo to the ISS.
- Starliner getting approval for conducting routine flights to and from the ISS would give NASA a backup and option to not depend on one company or vehicle for space launches.
About Atlas V Rocket:
- Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family.
- Originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Martin and Boeing.
- It is used for DoD (Department. Of Defense), NASA, and Commercial payloads.
- It is America’s longest-serving active rocket.
About International Space Station (ISS):
- ISS is the largest man-made object in space launched on November 20, 1998. It serves as a habitat for astronauts in space.
- Since 2011, the ISS has been continuously inhabited.
- ISS is a collaborative project of the United States (NASA), Russia’s (Roscosmos), Europe’s (ESA), Japan’s (JAXA), and Canada’s (CSA) space agencies.
- The International Space Station is in orbit about 400 kilometers above Earth.
- It travels around Earth at a speed of about 28,000 kilometers per hour. This means that it orbits Earth about every 90 minutes.
- Objectives: To expand our knowledge about space and microgravity and promote new scientific research. It also serves as an example of international cooperation.
About SpaceX:
- Space Exploration Technologies Corporation, commonly referred to as SpaceX, is an American spacecraft manufacturer, launch service provider, defense contractor and satellite communications company headquartered in Hawthorne, California.
- The company was founded in 2002 by Elon Musk with the goal of reducing space transportation costs and ultimately developing a sustainable colony on Mars.
Dragon capsule of SpaceX:
- The Dragon spacecraft is capable of carrying up to 7 passengers to and from Earth orbit, and beyond.
- It is the only spacecraft currently flying that is capable of returning significant amounts of cargo to Earth, and is the first private spacecraft to take humans to the space station.
5. A brief history of religion-based reservations in India; the question of Muslims’ inclusion
Subject: Polity
Sec: Constitution
Context:
- In this election season, India is debating fundamental constitutional questions around reservation.
Various debates regarding reservation:
- Can a secular country like India have religion-based reservation?
- Have Muslims ever been given reservation by reducing the quota for Scheduled Castes (SCs), Scheduled Tribes (STs), or Other Backward Classes (OBCs)?
- Does reservation for SCs that is limited to only certain religious denominations amount to reservation based on religion?
What the Indian Constitution says on religion-based reservations?
- The Constitution of 1949 dropped the word ‘minorities’ from Article 296 of the draft constitution (Article 335 of the present Constitution), but included Article 16(4) that enabled the state to make any provision for reservation in favor of any backward class of citizens which is not adequately represented in the services under the state.
- The first constitutional amendment inserted Article 15(4), which empowered the state to make any special provision for the advancement of any socially and educationally backward classes of citizens or for the Scheduled Castes and the Scheduled Tribes.
- Article 15 specifically prohibits the state from discriminating against citizens on grounds only of both religion and caste (along with sex, race, and place of birth).
- The crucial word in Articles 15 and 16 is ‘only’ — which implies that if a religious, racial, or caste group constitutes a “weaker section” under Article 46, or constitutes a backward class, it would be entitled to special provisions for its advancement.
- Article 341 of the Constitution and the 1950 Presidential Order state that only Hindus are entitled to inclusion within SCs.
- However, Sikhs were included within SCs in 1956, and Buddhists in 1990.
- Muslims and Christians remain excluded.
- It could be argued that this too, is ‘religion-based’ reservation.
Judicial pronouncements:
- The Supreme Court in E P Royappa vs State Of Tamil Nadu, 1973 case, has held that equality is a dynamic concept with many aspects and dimensions, and it cannot be “cribbed, cabined and confined” within traditional and doctrinaire limits.
- In M R Balaji vs State of Mysore (1962), the court noted that Muslims or for that matter Christians and Sikhs etc., are not excluded for the purpose of conferring the benefits under Articles 15(4) or 16(4).
- In Indra Sawhney (1992), the Supreme Court held that in a particular state, Muslim community as a whole may be found socially backward.
About Kerala Muslim sub-quota:
- Religion-based reservation was first introduced in 1936 in Travancore-Cochin state.
- In 1952, this was replaced by communal reservation.
- Muslims, who constituted 22% of the population, were included within the OBCs.
- After the state of Kerala was formed in 1956, all Muslims were included in one of eight sub-quota categories, and a sub-quota of 10% (now 12%) was created within the OBC quota.
Committee Recommendations:
- The Justice Rajinder Sachar Committee (2006) found that the Muslim community as a whole was almost as backward as SCs and STs, and more backward than non-Muslim OBCs.
- The Justice Ranganath Misra Committee (2007) suggested 15% reservation for minorities, including 10% for Muslims.