Subject: Biotech and Medical Sciences

Why in the News?

German researchers found that P. aeruginosa bacteria can switch a key gene (glpD) on or off, even though the bacteria are genetically identical — a survival trick called epigenetic bistability.

About Pseudomonas aeruginosa:

• Nature: Rod-shaped bacterium found in soil, water, and hospital environments.
• Pathogen Type: Opportunistic; infects mainly those with weakened immunity.
• Resistance: Forms biofilms (protective layers), making it highly resistant to antibiotics.
• Genetic Flexibility: Large genome (~6,000 genes) allows adaptation to diverse environments.

Impact on Humans:

• Hospital Infections: Leading cause of hospital-acquired infections.
• Vulnerable Groups: Burn patients, catheter users, cystic fibrosis patients.
• Diseases Caused: Keratitis (eye infection), urinary tract infections, pneumonia, bloodstream infections.
• Mortality: Strong antibiotic resistance makes treatment difficult, leading to high hospital deaths.

Recent Research Findings:

• Discovery: German researchers identified bistable expression of the glpD gene (active in some cells, inactive in others).
• Survival Advantage: This variability helps bacteria survive hostile conditions and trigger infections even from small populations.
• Experiments:
  • Cells with glpD active were more lethal in moth larvae and mouse immune models.
  • Cells without glpD showed reduced infection ability.
• Significance: On–off switching of glpD is a survival and infection strategy; targeting this mechanism may lead to new treatments for resistant infections.

Why in the News?

Kerala’s health department has issued an alert in Kozhikode district after three consecutive cases of the rare and highly fatal disease Primary Amoebic Meningoencephalitis (PAM) were reported.

About Primary Amoebic Meningoencephalitis (PAM):

• Cause: Rare and usually fatal infection caused by Naegleria fowleri, known as the “brain-eating amoeba.”
• Habitat: Thrives in warm freshwater up to 46°C (115°F).
• Entry: Enters through the nose during swimming or water activities, travels via olfactory nerve to the brain.
• Impact: Destroys brain tissue and causes severe swelling.
• Transmission: Not communicable from person to person.
• Symptoms: Headache, fever, nausea, vomiting, stiff neck, confusion, seizures, hallucinations, coma, and death.
• Progression: According to the Centers for Disease Control and Prevention (CDC), most cases result in death within 1–18 days of symptom onset.

Diagnosis and Treatment:

• Diagnosis:
  • Very difficult due to rarity.
  • Confirmed by Polymerase Chain Reaction (PCR) test of cerebrospinal fluid (CSF).
  • Frequently misdiagnosed as bacterial or viral meningitis.
• Treatment:
  • No single therapy effectively established.
  • Managed per CDC guidelines using drug combinations such as: Medical interventions typically involve a combination of drugs, including amphotericin B, azithromycin, fluconazole, rifampin, miltefosine, and dexamethasone.

Why in the News?

Researchers from UK and China have developed a bioelectronic device where genetically engineered E. Coli bacteria act as self-powered chemical bio-sensor.

About Escherichia coli (E. coli) Bacteria:

• Overview: Gram-negative, rod-shaped bacterium that inhabits the lower intestine of warm-blooded animals.
• Family: Belongs to the Enterobacteriaceae family.
• Harmless vs Pathogenic: Most strains are harmless, but some (e.g., E. coli O157:H7) cause severe foodborne illness, diarrhoea, and kidney complications.
• Gut Role: Contributes to vitamin K₂ synthesis and maintains gut microbiota balance.
• Transmission: Pathogenic strains spread via contaminated food, water, or direct contact, leading to outbreaks.
• Diagnostic Importance: Presence in water is a key indicator of faecal contamination.

Bio-Sensors Generated Using E. coli

• Innovation: Genetically engineered E. coli used as self-powered chemical biosensors.
• Mechanism: Detect compounds, process signals, and produce electrical outputs compatible with low-cost electronics.
• Modules:
  • Sensing Module: Detects target molecules.
  • Processing Module: Amplifies or modifies signals.
  • Output Module: Produces phenazines measurable via electrochemistry.
• Applications:
  • Detected arabinose (plant sugar) within 2 hours.
  • Detected mercury ions in water at trace levels (below WHO safety limits) within 3 hours.
  • Demonstrated an “AND” logic gate, producing signals only when two molecules were present together.
• Significance:
  • Cheaper, programmable, and robust alternative to enzyme-based biosensors.
  • Potential in environmental monitoring, water safety, medical diagnostics, and bioelectronics.

Why in the News?

Recently, Chinese scientists identified a key gene, Chalk9, that controls chalkiness in rice, offering a breakthrough for crop improvement.

About Chalk9 Gene in Rice:

• Overview: Chalk9 is a gene found on chromosome 9 of rice.
• Function: Encodes the enzyme E3 ubiquitin ligase, which regulates protein degradation.
• Target Protein: Acts on OsEBP89, a regulator of starch-synthesis genes Wx and SSP.
• Chalk9-L Variant: Promotes OsEBP89 degradation → prevents excess starch accumulation → results in low chalkiness and translucent grains.
• Chalk9-H Variant: Fails to degrade OsEBP89 efficiently → leads to starch buildup → high chalkiness and brittle grains.

Significance:

• Grain Quality: Chalkiness lowers milling recovery and reduces rice’s commercial value.
• Genetic Solution: Discovery of Chalk9 offers a direct genetic tool to reduce chalkiness.
• Breeding Advantage: Rice breeding programs can introduce Chalk9-L to produce premium low-chalk rice.
• Economic Impact: Improves farmer income and enhances food security.
• Consumer Preference: Meets demand for better quality, translucent rice varieties.

Why in the News?

Walter Kauzmann’s 1959 idea that protein folding relies on water-loving and water-avoiding parts has now been challenged by new research showing protein cores are more flexible than once believed.

Protein and Protein Folding – Overview

• Proteins: Biological macromolecules made of 20 amino acids in specific sequences.
• Folding: Sequence dictates 3D shape, essential for function.
• Water Interaction:
  • Hydrophilic (e.g., lysine) → outer surface.
  • Hydrophobic (e.g., tryptophan) → buried in core.
• Kauzmann Hypothesis (1959): Proteins have a hydrophobic core and hydrophilic surface, guiding folding.
• 1960s X-ray Evidence: Confirmed hydrophobic residues inside, hydrophilic outside.
• Earlier Belief: Core was highly sensitive—small changes could destabilize protein.

Recent Research:

• Study Design: Tested 78,125 amino acid combos at 7 sites in cores of 3 proteins:
  • Human SH3 domain (FYN tyrosine kinase)
  • Barley CI-2A protein
  • E. coli CspA protein
• Findings:
  • Many changes harmful, but thousands stable (e.g., SH3-FYN had 12,000+ stable conformations).
  • Machine learning accurately predicted stability even with <25% sequence similarity.

Implications:

• Protein Engineering: Core modifications may be possible without losing stability—beneficial for therapeutics.
• Evolutionary Insight: Protein cores may have been more adaptable during evolution than once thought.

Why in the News?

The World Health Organization (WHO) has reclassified hepatitis D virus (HDV) as carcinogenic, following the International Agency for Research on Cancer (IARC) assessment based on data from The Lancet Oncology.

About Hepatitis D:

• What is it: Hepatitis D is a serious liver infection caused by the hepatitis D virus (HDV).
• Cause: Hepatitis D virus (HDV), an incomplete virus needing hepatitis B virus (HBV) for replication.
• Infection Types:
  • Co-infection – HDV + HBV at the same time.
  • Superinfection – HDV infects someone already with HBV.
• Transmission: Parenteral exposure (injections, transfusions), mother-to-child, sexual contact.
• Diagnosis: Blood tests for HDV antibodies and HDV-RNA.
• Prevention: HBV vaccination, safe blood practices, safe sex, screening, avoid needle sharing.

Why Hepatitis D is Carcinogenic?

• Causes more severe liver damage than HBV alone.
• HBV–HDV co-infection raises liver cancer risk 2–6 times compared to HBV-only cases.
• Up to 75% develop cirrhosis within 15 years.
• Can cause cancer even without cirrhosis due to HBV DNA integration + HDV-induced damage.

Why in the News?

With haemophilia care evolving globally, the shift from reactive to preventive treatment has brought Prophylaxis Therapy to the forefront of modern clinical practice.

About Haemophilia:

• What is it: Rare genetic bleeding disorder due to deficiency of clotting factors, mainly Factor VIII (Haemophilia A).
• Effect: Causes prolonged bleeding, even from minor injuries; can lead to internal bleeds in joints, muscles, or brain.
• Key Symptoms: Excessive bleeding, painful joint swelling, risk of disability or brain hemorrhage.
• Prevalence: Estimated 1–1.5 lakh cases in India; only ~29,000 diagnosed (~20%).
• Underdiagnosis Causes: Low awareness, poor access to diagnostics, and socio-economic challenges.
• Impact if Untreated: Each untreated bleed may reduce lifespan by ~16 days; leads to pain, disability, missed school/work, and job loss.

Prophylaxis (Regular Replacement Therapy) and its Benefits:

• What It Is: Regular infusion of clotting factors or non-factor therapies to prevent bleeds.
• Global Standard: Replaces on-demand therapy; adopted as best practice in developed countries.
• Joint Protection: Prevents recurrent bleeds, avoids deformities and long-term disability.
• Quality of Life: Reduces pain and fear, enables normal schooling, work, and social life.
• Healthcare Savings: Cuts emergency visits, hospital stays, and long-term costs.
• Global Status: ~90% of haemophilia patients in developed countries are on prophylaxis.
• India’s Progress: On-demand remains common; some states offer prophylaxis for children under 10.

Why in the News?

While most medicines are small molecule drugs with simple structures, a newer class—biologics and biosimilars—is reshaping modern medicine with their complex, targeted action.

About Biologics & Biosimilars:

• Biologics-

• • Overview: Large, complex drugs made from living cells or organisms.
  • Examples: Insulin (~5,800 daltons), Remicade (~150,000 daltons).
  • Nature: Slight structural variations possible; used for cancer, autoimmune diseases, hormone therapy.

• Biosimilars-

• • Overview: Near-identical versions of biologics, made after patent expiry.
  • Not Generics: Due to complex cell-based production, they’re similar but not identical.
  • Use: Offer lower-cost alternatives to high-end biologics.

Regulation and Reform:

• Current Barriers: Biosimilars need costly trials (animal + clinical), unlike generics.
• Global Moves: UK and USA are easing animal trial norms (organ-on-chip, human models).
• India: Still follows older norms; waivers under review, but clinical trials still mandatory.

Significance for India:

• Access: Generic small molecules transformed Indian healthcare.
• Opportunity: Affordable biosimilars can do the same for chronic and rare diseases.
• Urgency: Regulatory reform is key to reduce costs, speed up access, and widen healthcare coverage.