- Education and Science»
- Life Sciences
Useful And Extraordinary Microbes
Not all microbes are harmful, many are very useful to us and becomes an integral part of our life.
¢ World is filled with living creatures.
¢ Microscopic & Macroscopic
¢ What are microorganisms?
¢ Organisms that are too small to be seen clearly with the naked eye.
¢ Generally single cells, but some exist as cell clusters; often work as a community.
There are five main types of microorganisms. bacteria, fungi, algae protozoans and viruses
PROKARYOTIC (bacteria) and
EUKARYOTIC (fungi, algae protozoans )
General characteristics of a microbe:
- Very small, Microscopic
- Size is 1 micrometer
- Shape: coccus, bacillus, streptococcus, staphylococcus.
- SMALL BACTERIA
¢ An archaeon is smaller than any cellular organism previously known. It is about 200 nm (0.2 μm) diameter.
¢ There are tiny bacteria involved in processes like calcification of our arteries. These bacteria have been termed as nanobacteria.
¢ Since these alleged organisms really do not fit in any modern understanding of what cells are, solid evidence is needed -- and is lacking.
- THE BIGGEST MICROBE
¢ A unicellular green alga Acetabularia, whose cells can be several centimeters long.
¢ Because of the large size, scientists are studying the relationship between their nucleus and cytoplasm.
- BIG BACTERIA
¢ Epulopiscium (1985) and
Thiomargarita (1999) --
¢ Bacteria big enough to be seen with the naked eye. These bacteria ---at least the larger specimens--- approach 1 millimeter in size.
¢ A giant bacterium, Thiomargarita "sulfur pearl of Namibia,“.
¢ The bacteria (3/4 mm wide) is about 100 times larger than the largest known, Epulopiscum fishelsoni.
- A HUGE VIRUS
¢ The most recent challenge to the simplicity of viruses is the mimivirus (2003), which grows in the protozoan Acanthamoeba polyphaga.
¢ It has about three times more genetic material (DNA) than any previously known virus -- more DNA than some bacteria.
¢ Size: 400nm diameter.
¢ Now even bigger virus than mimivirus is mamavirus (2008).
- MULTICELLULAR BACTERIA
¢ Usually Single celled.
¢ The myxobacteria probably have the most complex bacterial life cycle. They spend part of their life as free-living individual bacterial cells.
¢ Aggregate to form a fruiting body, an organized multicellular structure.
¢ Myxobacteria fruiting bodies
- 6. BACTERIA THAT EAT OTHER BACTERIA
¢ The story of predatory bacteria starts with Bdellovibrio, a type of bacterium that obligatory lives within other bacterial cells.
¢ Since they kill the bacteria that they infect, Bdellovibrios form clear regions on a lawn of dense bacterial growth, much like bacterial viruses form plaques. But they are not viruses.
¢ They are cellular, with rather ordinary bacterial cells. They burrow into a bacterial cell, and grow there.
- 7. SQUARE BACTERIA
¢ Shape of Bacteria?
¢ Round or rod shaped
¢ In 1980, Scientist found square Bacteria with sharp corners, in concentrated salt solutions.
¢ They are very thin about 200nm or 0.2mm thick.
¢ These square bacteria are Archaea.
¢ They have been named Haloquadratum walsbyi.
- 8. MAGNETIC MICROBES
¢ In nature, organisms use a variety of methods to figure out where they are and where they need to be going.
¢ Some organisms use the earth's geomagnetic field to orient themselves and navigate through their environment.
¢ Organisms that use the earth's geomagnetic field have some type of internal compass. The smallest organisms that use this navigational method are called magnetotactic bacteria.
- 9. BACTERIA THAT GIVE BIRTH
¢ Bacteria divide by binary fission: they grow bigger, and then divide in two.
¢ But there are exceptions. An interesting type of exception occurs when bacteria seem to give birth to live young. That is, they develop new cells inside, and then liberate these daughter cells.
¢ One of the first cases where this type of bacterial reproduction was seen was with Epulopiscium. Then it was found in the bacterium Metabacterium.
¢ Thus both Metabacterium and Epulopiscium "give birth to live young”.
¢ Metabacterium with four daughter spores. The figure at the right shows a single Metabacterium polyspora cell containing four spores, with the bright appearance that is typical of bacterial endospores. The individual spores are several μm long.
¢ Strange Facts and Bacterial Records!!!
¢ Microbes thrive in an amazing diversity of habitats in extremes of heat, cold, radiation, pressure, salinity, acidity, and darkness, and often where no other life forms could exist.
¢ High temperature
¢ Thermal vents and hot springs
¢ Hydrothermal Vents- Black smokers at 350 oC
¢ Obsidian Pool,
¢ Yellowstone National Park
¢ Low temperature
¢ Arctic and Antarctic1/2 of earth’s surface is oceans between 1-40C Deep sea –10C to 40C
¢ some thermal vents & hot springs
¢ pH 0-1 of waters
¢ at Iron Mountain
¢ Mono Lake- alkaline
¢ soda lake, pH 9 &
¢ salinity 8%
¢ Highly saline
¢ Natural salt lakes and manmade pools
¢ Sometimes occurs with extreme alkalinity
¢ One of the most unusual bacteria is one that is very highly resistant to what scientists had considered to be absolutely lethal radiation levels.
¢ Deinococcus radiodurans is very remarkable for its ability to withstand radiation levels over 1000 times higher than that which would completely debilitate any human on earth.
¢ This organism was first found in food in the 1950's, food supposedly sterilized by radiation treatments.
¢ The Deep Sea: Bacteria ‘known as Extreme Barophiles’ live at depths of >10000 m and are able to survive pressures in excess of 1000 times the air pressure at sea level; and they cannot function properly at pressures less than 400 atmospheres and may die in a couple of hours if brought to the surface.
¢ Life On Mars??? No one knows for sure yet!
¢ But in August 1996, scientists announced that they had extracted what they believed to be fossils of an unknown bacillus shaped microorganism from inside a meteorite from Mars found in Antarctica..
¢ The meteorite left Mars 16 million years ago and landed in Antarctica 13 thousand years ago.
¢ This may support the theory that life did or does still exist on Mars!
¢ The Sky: Some bacteria spend their whole lives in the atmosphere, growing and reproducing in the clouds above our heads.
¢ Underground: Chemolithotrophs found in Basalt deposits 1500m (4700 ft) underground in solid rock.
¢ On Ice: Some bacterial species live in the ice of glaciers and others have often found in the snows of the North and South poles at -17 and -85°C.
¢ Not So Cool: Some bacteria have learned to live in hot springs. Some species are happy at 75°C while others think even this is cool. Species of Aquifex can live in water as hot as 95°C. Archaea are happy to grow deep sea hydrothermal vents at 106°C
¢ Fast Movers:
¢ Some bacteria can move by flagella that enable them to obtain speeds as high as 0.00017 km/ hr. This may not seem very fast, but remember that we are talking about very small organisms.
¢ They are travelling at about 50-60 body lengths/ sec which is equivalent to a 6 ft tall man running at 100 m/ sec, 9 times faster than the world record. Cheetahs, are the fastest animals on land but even they only move at about 25 body lengths/ sec.
- Some microorganisms cause diseases in plants and animals. Such disease causing microorganisms are called pathogens.
- Some microorganisms grow in food substances and produce toxic substances and makes the food poisonous. Food poisoning causes illness and even death.
- Some microorganisms spoil materials like clothing, leather, wood etc.
- pollution control
Making bread :-
The unicellular fungus called yeast reproduces in flour dough and produces carbon dioxide during respiration which makes the dough soft and helps in making bread, cakes, biscuits, pastries etc.
Making curd from milk :-
The bacterium called Lactobacillus reproduces in milk and helps to convert milk into curd.
Making alcohol :-
The fungus called yeast reproduces in sugar solution and converts it into alcohol.
Some bacteria and fungi are used to make medicines which kill or stops the growth of disease causing microorganisms.
Such medicines are called antibiotics.
Streptomycin, Tetracycline, Erythromycin etc.
Escherichia coli, or E. coli, is being used by University of Washington chemical engineer James Carothers to produce a chemical precursor of pristinamycin, an antibiotic used to treat staph infections.
Saccharomyces cerevisiae Biologist Jay Keasling of the University of California in Berkeley has shown how this species of yeast can be engineered to produce artemisinic acid, a key chemical compound in anti-malaria drugs, normally extracted from the wormwood tree.
Bacteriophages – “bacteria-eaters”, viruses that use bacteria to multiply
In the 1990s, bacteriophage research became an alternative for scientists worried about antibiotic resistance.
Researchers in America followed the example of scientists in Western Europe who were treating patients with bacteriophages and obtaining great results.
When antibiotics don't work for a bacterial infection, doctors can use bacteriophages to kill the bacteria. Although ironic, a virus can make us feel better!
Metal ores are present in various forms in nature. Rocks are rich source of metals.
Microbes like algae and bacteria (Pseudomonas, Corynebacterium etc) are involved in the leaching and migration of elements as well as in the formation of minerals under suitable conditions.
Metal removal by microbes in water:
The microorganisms growing in marine water, fresh water and wastewater like bacillus and zooglea sps produces extracellular polymer which accumulates metals such as iron, copper, cadmium and uranium. These metals are released from the biomass upon treatment with HCl.
Fungal mycelia also removes metals from wastewater and detoxify the efflutents.
Biodegradation of petroleum and xenobiotics : fungi and bacteria are main agents that decompose oil and oil products.
Xenobiotics (man made compounds like pesticides) can be metabolised by certain microbes like Aspergillus niger, Pseudomonas putida etc.
Microbial plastics: Certain bacterial species naturally synthesize polymers such as poly beta hydroxy butyrate.
Alcaligenes eutrophus, is a useful bacterium having the capability of making plastics.
Biofiltration : It is a new technology used to purify contaminated air evolved from organic and inorganic matter by involving microorganisms. It is a low cost technology.
First biofilters were built in USA in 1960s.
Most of the microbial biofilters are made from bacteria (endospore formers), some are actinomycetes (steptomyces spp.) and few are Fungi (Rhizopus, Penicillium etc).
Microbes are used to decompose organic matter into manure by involving earthworms which increases the fertility of soil.
Biogas plant- The fermentative methanogenic, facultative anaerobic and acidogenic bacteria are used to convert organic matter into gases like methane, CO2, acetate, water and other products.
Used for cooking, lighting and in internal combustion engines to power pumps and electric generators.
Sewage treatment- The bacteria, fungi and viruses present in the wastewater from household, agriculture and industries, decompose the organic matter into gases to be used in biogas plant.
Biofertilizers are formulations of microorganisms which are able to fix atmospheric nitrogen in the available form for plants either by living freely in the soil or by associated symbiotically with plants.
The first major products of agricultural biotechnology was Bacillus thuringiensis, producing proteins that are toxic to many insects.
Now, scientists have spliced genes of it into crops, that produces toxins fatal to crop damaging pests, but harmless to "good" bugs.
Carbon, the main component of most diamonds, usually contains an isotope of light carbon (12C), which is utilized by some living organisms. Therefore, diamonds with large amounts of the isotope 12C, are believed to have an organic origin.
These were formed from carbon near hydrothermal vents which was also utilized by the bacterial communities near the vents.
Thus through time, heat and pressure were able to turn the carbon along with the bacterial colonies into diamonds.
"So, those sparklers of yours may just be clumps
of billion-year-old bacterial corpses"
Chocolate comes from the seeds of the Cacao tree.
The seeds come in pods and the only way to retrieve the seeds are to ferment them with yeasts and Lactobacilli and Acetobacter.
The Lactobacillus secretes an acid to help break apart the pod.
Alkalothermophilic thermomonospora produces enzyme cellulase, which when mixed with a coarse denim cloth reduces its hairiness and makes it softer and lighter.
It gives same appearance as a stone wash, causes no damage to drums of washing machines by preventing wear and tear of the material.
Finish can be controlled to desired level by controlling the amount of enzyme.
Electric currents running through sea beds. Bacteria that functions as living cables. An unknown type of long, multi-cellular bacteria were always present when electric currents were around. Contains a bundle of insulated wires that leads an electric current from one end to the other.
Moreover, they could disrupt the currents when they pulled a thin wire through the seabed -- a possible indication of broken connections.
Apply electric current to this microbe,
and you produce pure methane,
according to microbiologist
Bruce Logan of Pennsylvania State University.
Increasingly, methane is being mined through controversial methods like fracking, but with Logan’s technique, we could achieve production of methane gas to power our appliances and heat our homes.
Halobacterium, may hold the key to protect astronauts from one of the greatest threats they would face during a mission to Mars: space radiation.
The harsh radiation of interplanetary space can penetrate astronauts' bodies, damaging the DNA in their cells, which can cause cancer and other illnesses.
Halobacterium appears to be a master of the complex art of DNA repair. This mastery is what scientists want to learn from.
Lightning bugs make light, but interestingly enough, bacteria produce light in basically the same process called bioluminescence.
Luciferin emits visible light! The color of light (orange, yellow, yellow-green, or blue-green ) depends on the kind of luciferase and amount of oxidation of the vitamin attached to the luciferin.
Christmas tree could grow its own lights.
the luciferin would be mixed into a special fertilizer sold with the tree.
Bacteria Cupriavidus metallidurans,can extract pure gold from the toxic solution gold chloride (a totally artificial salt).
Kashefi and Brown set to work designing a half-experiment, half-art-exhibit that exposes C. metallidurans to gold chloride in a hydrogen-gas-rich atmosphere that serves as a source of food. Over the course of a week, the bacteria gradually strip-mined the toxic liquid, leaving flecks of pure 24-karat gold behind.
Trinitrotoluene, TNT, is a problematic explosive that contaminates the soil in areas where ammunition is kept.
Bacteria named Clostridium bifermentans is able to break down this contaminant.
When provided with starch as energy source, the bacteria can break down the TNT through co-metabolism by broken-down TNT as a source of carbon.
What Microbiologists Do ???
Work in almost every industry - from food, agriculture and pollution control to biotechnology, pharmaceuticals and health, government agencies and labs, in education as teachers and researchers.
No one microbiologist can study everything! That's why people who become microbiologists usually focus on a particular microbe or research area.
1. Bacteriologists focus on bacteria.
2. Virologists specialize in viruses.
3. Mycologists study fungi.
4. Epidemiologists track down outbreaks of disease
5. Immunologists study how the body defends itself against microbial invaders?
The conclusion herein is-
Humans can’t survive without a biodiversity of microbes functioning in a manner that makes our life form possible.
Regardless of human actions, microbes will survive some geological time after mankind no longer inhabits the earth