Microbiology & Epidemiology

Viruses can survive in oceans, infect bacteria, and alter host cell transcription. ❌Statement I: False. Viruses can survive in ocean waters, and marine viruses are highly abundant. ❌Statement II: False. Viruses can infect bacteria; for example, bacteriophages specifically infect bacteria. ❌Statement III: False. Viruses can alter host transcription and modify host gene expression. None of the statements are correct.

Monoclonal antibodies are lab-made proteins that target specific antigens and can be used to treat viral infections like Nipah virus. * ✅ I. Man-made proteins – Created by cloning a single immune cell type. * ✅II. Bind to specific antigens – Help stimulate or guide immune response. * ✅III. Used in viral infections – Applied in treating infections like Nipah virus. All three statements are correct.

* Statement 1 is correct: Pyrolobus fumarii, an archaeon living at 113 °C in Atlantic hydrothermal vents.Pyrococcus furiosus, an archaeon which thrives at 100 °C, first discovered in Italy near a volcanic vent.  * Statement 2 is correct: Psychrophiles or cryophiles (adj. psychrophilic or cryophilic) are extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from 20 °C to 20 °C.  * Statement 3 is correct: Acidophiles are microorganisms that show optimal growth in highly acidic environments. These are of two types. The extreme acidophiles dwell in environments with a pH value < 3, and moderate acidophiles grow optimally in conditions having pH values ranging between 3 and 5.

 The Wolbachia method is a biological method that utilises the Wolbachia bacteria to control the spread of mosquito-borne diseases, particularly dengue fever. * Wolbachia naturally infects some insect species, but not Aedes aegypti mosquitoes, the primary vector for dengue fever transmission. Scientists introduce Wolbachia into Aedes aegypti populations.  Wolbachia reduces the ability of these mosquitoes to transmit dengue virus.  * As Wolbachia spreads through the mosquito population, it can significantly reduce the incidence of dengue fever.  * This method offers a natural and sustainable approach to controlling dengue fever, a major public health concern in tropical and subtropical regions.

 All four statements are correct.  * Medicinal mushrooms: Certain mushroom species have been used in traditional medicine for centuries and are still being studied for their potential health benefits. Examples include reishi mushrooms (Ganoderma lucidum) for immune system support and lion's mane mushrooms (Hericium erinaceus) for cognitive function. * Psychoactive mushrooms: Some mushrooms contain psilocybin, a naturally occurring psychoactive compound that can induce hallucinations. These are commonly referred to as "magic mushrooms" or psilocybin mushrooms. * Insecticidal mushrooms: Some mushroom species produce natural compounds that can repel or even kill insects. These compounds act as a defence mechanism for the mushrooms against insect pests. * Bioluminescent mushrooms: A less common but fascinating property, bioluminescence, is found in some mushroom species. These mushrooms can produce and emit light, creating a glowing effect.

* Statement 1 is correct: Biofilms are a major concern in healthcare. They can form on implanted devices like catheters, heart valves, and artificial joints within human tissues. These biofilms can harbour bacteria that are difficult to eradicate with antibiotics, leading to chronic infections and potential implant failure. * Statement 2 is correct: Biofilms can also form on food and food processing surfaces. This can contaminate food with bacteria and contribute to spoilage. Biofilms on these surfaces are also challenging to remove due to their protective matrix. * Statement 3 is correct: Bacteria within biofilms can exhibit increased resistance to antibiotics. The biofilm matrix acts as a barrier, making it harder for antibiotics to reach and kill the bacteria. Additionally, bacteria within biofilms can communicate and share genetic material, potentially promoting the spread of antibiotic resistance genes. All three statements are correct.

Statement 1 is correct. Probiotics can be made from both bacteria and yeast. Some common probiotic strains include bacteria like Lactobacillus and Bifidobacterium, and yeasts like Saccharomyces boulardii. Statement 2 is incorrect. The organisms in probiotics are naturally found in the human gut. We have a complex gut microbiome with trillions of bacteria and other microbes, some of which are beneficial. Probiotics are supposed to introduce specific strains of these beneficial microbes to improve gut health. Statement 3 is correct. Probiotics might help with lactose digestion, but it depends. Lactose intolerance is caused by a lack of the enzyme lactase, which breaks down lactose (milk sugar) in the gut. Some probiotic strains might produce lactase, potentially aiding digestion in lactose-intolerant individuals.

Statement 1 is correct. Genetic engineering in vaccine development works by modifying the genetic material of viruses, bacteria, or lab-grown cells to produce specific proteins that trigger an immune response. Scientists first identify a target protein from a pathogen that can help the immune system recognize and fight it. They then insert the gene coding for this protein into a harmless virus, bacterial cell, or a lab-grown system, which acts as a factory to produce large amounts of the antigen. The antigen is then purified and combined with other ingredients to create the final vaccine. When injected, the vaccine stimulates the immune system to recognize and attack the actual pathogen if encountered in the future. This approach is used in various vaccines, including mRNA vaccines like those for COVID-19 and recombinant protein vaccines like the Hepatitis B vaccine. Statement 2 is correct. Bacteria and viruses are commonly used as vectors in recombinant vector vaccines. These vectors serve as delivery vehicles to transport genetic material from the target pathogen into host cells, where the antigens are produced. The host immune system then recognizes these antigens and mounts an immune response. | Vector Type | Examples of Vectors |
|------------------|--------------------------------------------------------------------------------------------------------|
| Viral Vectors | Adenovirus, Vaccinia Virus (MVA), Vesicular Stomatitis Virus (VSV), Measles Virus, Influenza Virus |
| Bacterial Vectors| Salmonella typhimurium, Listeria monocytogenes, Mycobacterium bovis (BCG) |
| Fungal Vectors | Saccharomyces cerevisiae (Yeast) |
| Protozoan Vectors| Leishmania donovani, Trypanosoma cruzi |

* The term 'ACE2' is talked about in the context of the spread of viral diseases, particularly COVID-19. * ACE2 stands for Angiotensin-Converting Enzyme 2. It's a protein found on the surface of many cell types in the human body, including those in the lungs, heart, kidneys, and intestines. * Here's why ACE2 is significant: * Receptor for SARS-CoV-2: The spike protein on the surface of the SARS-CoV-2 virus, the virus that causes COVID-19, binds to the ACE2 receptor in human cells. This binding is a critical step in the process of how the virus infects cells. * Multiple organ infection: Since ACE2 is expressed in various organs, it provides the virus with multiple potential entry points. This can contribute to the multi-organ complications sometimes associated with COVID-19. * Focus of research: Understanding the interaction between the virus and ACE2 is a major area of research for scientists developing vaccines and treatments for COVID-19.

Statement 1 is incorrect: Adenoviruses have double-stranded DNA genomes. Retroviruses have single-stranded RNA genomes. Statement 2 is correct: Adenoviruses are one of the many viruses that can cause the common cold. AIDS (Acquired Immunodeficiency Syndrome) is caused by the Human Immunodeficiency Virus (HIV), which is a type of retrovirus.