The cell wall also makes Gram staining possible. Gram staining is a method of staining bacteria involving crystal violet dye, iodine, and the counterstain safranin. Many bacteria can be classified into one of two types: gram-positive, which show the stain and appear violet in colour under a microscope, and gram-negative, which only show the counterstain, and appear red.
Bacteria And It’s Characteristic
Keywords: Bacteria, Prokaryotic, Bacillus, Cocci, Spirilla, Binary fission, Spores, Genetics, Photosynthesis, Chemosynthesis, Reproduction of Bacteria, Classification of Bacteria, Habitat of Bacteria
What are bacteria?
Bacteria are single celled microbes. The cell structure is simpler than that of other organisms as there is no nucleus or membrane bound organelles. Instead their control centre containing the genetic information is contained in a single loop of DNA. Some bacteria have an extra circle of genetic material called a plasmid. The plasmid often contains genes that give the bacterium some advantage over other bacteria. For example, it may contain a gene that makes the bacterium resistant to a certain antibiotic.
Bacteria are classified into 5 groups according to their basic shapes: spherical (cocci), rod (bacilli), spiral (spirilla), comma (vibrios) or corkscrew (spirochetes). They can exist as single cells, in pairs, chains or clusters. Artwork of bacterial cells becoming resistant to antibiotics.
Bacteria are found in every habitat on Earth: soil, rock, oceans and even arctic snow. Some live in or on other organisms including plants and animals including humans. There are approximately 10 times as many bacterial cells as human cells in the human body. A lot of these bacterial cells are found lining the digestive system. Some bacteria live in the soil or on dead plant matter where they play an important role in the cycling of nutrients. Some types cause food spoilage and crop damage but others are incredibly useful in the production of fermented foods such as yoghurt and soy sauce. Relatively few bacteria are parasites or pathogens that cause disease in animals and plants.
Gram Reaction of Bacteria:
The cell wall also makes Gram staining possible. Gram staining is a method of staining bacteria involving crystal violet dye, iodine, and the counterstain safranin. Many bacteria can be classified into one of two types: gram-positive, which show the stain and appear violet in colour under a microscope, and gram-negative, which only show the counterstain, and appear red. Gram-positive bacteria appear violet because they have thick cell walls that trap the crystal violet-iodine complex. The thin cell walls of gram-negative bacteria cannot hold the violet-iodine complex, but they can hold safranin. This makes gram-negative bacteria appear red under Gram staining. Gram staining is used for general identification of bacteria or to detect the presence of certain bacteria; it cannot be used to identify bacteria in any specific way, such as at a species level. Examples of gram-positive bacteria include the genera Listeria, Streptococcus, and Bacillus, while gram-negative bacteria include Proteobacteria, green sulphur bacteria, and cyanobacteria.
Binary fission: In this process the bacterium, which is a single cell, divides into two identical daughter cells. Binary fission begins when the DNA of the bacterium divides into two (replicates). The bacterial cell then elongates and splits into two daughter cells each with identical DNA to the parent cell. Each daughter cell is a clone of the parent cell.
When conditions are favourable such as the right temperature and nutrients are available, some bacteria like Escherichia coli can divide every 20 minutes. This means that in just seven hours one bacterium can generate 2,097,152 bacteria.
Transfer of genetic material: Cells acquire new genetic material through processes known as conjugation, transformation, or transduction. These processes can make bacteria stronger and more able to resist threats, such as antibiotic medication.
Spores: When some types of bacteria are low on resources, they can form spores. Spores hold the organism’s DNA material and contain the enzymes needed for germination. They are very resistant to environmental stresses. The spores can remain inactive for centuries, until the right conditions occur. Then they can reactivate and become bacteria.
Increasing levels of antimicrobial resistance (AMR) mean that conditions such as tuberculosis, HIV and malaria are again becoming increasingly difficult to treat. Antimicrobial resistance also compromises the success of surgery, organ transplantation, childbirth and chemotherapy, making many treatments riskier.
The human activities that are making the problem worse – such as the overuse of antibiotics in medicine, the proliferation of resistant microbes in care homes and hospitals, and the use of medically vital antimicrobials as growth promoters or prophylactics in livestock and crop production.
The briefing also considers the actions needed to tackle the spread of AMR, including reducing non-essential usage of antimicrobials and investment in research to develop new antimicrobials and alternative antimicrobial therapies, and the steps that are already being taken by international bodies such as the World Health Organization WHO.
Heterotrophic bacteria, or heterotrophs, get their energy through consuming organic carbon. Most absorb dead organic material, such as decomposing flesh. Some of these parasitic bacteria kill their host, while others help them.
Autotrophic bacteria (or just autotrophs) make their own food; by either ways
Photosynthesis: using sunlight, water and carbon dioxide
Chemosynthesis: using carbon dioxide, water, and chemicals such as ammonia, nitrogen, sulphur, etc.
Lactobacillus acidophilus : Found in dairy products, it is an anaerobic bacteria that converts sugars and lactose into lactic acid. This beneficial bacterium is added in food supplements for use in therapeutic intervention.
Nitrogen-Fixing Bacteria: Another group of useful bacteria is the nitrogen-fixing bacteria, which are crucial for plant growth. They help in assimilation of nitrogen from the atmosphere and soil, and covert it into usable compounds for plants.
Helicobacter pylori: It is a type of bacteria that affects the digestive tract and causes medical symptoms. This helix-shaped bacterial strain may cause inflammation of stomach lining (stomach ulcer) and other digestive problems.
Stomach Bacteria: Can you believe that the total number of body cells is lesser than that of bacteria that inhabit the human body? Yes, it is true and they are found in the skin, stomach, and other internal organs. Most of the stomach bacteria are harmless.