The popular notion of bacteria is that of disease-causing and infectious organisms. Certainly there do exist bacteria that are malignant but the human body contains several types of bacteria, which are benign. Read on to know about both the helpful and harmful types of bacteria. Bacteria are an important group of living organisms. Most of them are microscopic and unicellular, with a relatively simple cell structure, lacking a cell nucleus, and organelles such as mitochondria and chloroplasts. A tough protective layer called a cell wall encloses almost all kinds of bacteria. The cell wall gives the bacterium its distinctive shape and enables it to live in a wide range of environments. A capsule, a slimy layer outside the cell wall, further encloses certain species. The capsule causes the cell to be resistant to destructive chemicals. All bacteria possess a cell membrane, an elastic, bag-like structure immediately inside the cell wall. Small molecules of food enter the cell through pores in this membrane, but large molecules cannot pass through it. Inside the membrane is the cytoplasm, a jellylike, soft substance. The cytoplasm contains chemicals called enzymes, which help build cell parts and break down food.
Bacteria can be categorized as living cells unlike viruses. Bacteria are found everywhere from the tallest mountains to the deepest parts of an ocean on earth. The air is replete with bacteria. Certain bacteria spend their whole lives in the atmosphere, reproducing and growing in the clouds. Although bacteria lack distinct nuclear structures common to the cells of higher organisms like animals and plants and are able to reproduce successfully and transfer genetic information from one generation to the next. Motile bacteria can move about, either using bacterial gliding, flagella or changes of buoyancy.
Almost 99% bacteria are helpful. Disease is caused by only a few of them. Water, food, and air carry bacteria from one person to another. Bacteria can be classified into three types on the basis of shape. The sphere shaped bacteria, rod shaped bacteria and spiral bacteria are the three types.
Helpful bacteria
Certain types of bacteria live in the intestines of human beings. They help in digestion and in destroying the harmful organisms. Intestinal bacteria also produce some vitamins required by the human body.
Certain bacteria help break down lactose in the digestive tract.
It is observed that Infants who were administered the bacteria Lactobacillus reuteri or Bifidobacterium had fewer and shorter episodes of diarrhea.
Fermented milk containing the live bacteria Lactobacillus casei helps in eradicating harmful bacteria Helicobacter pylori in children.
Saccharomyces boulardii is found to reduce the risk of antibiotic-associated diarrhea in children.
Some bacteria present on the skin protect us from the spread of certain fungus.
It was found that DNA damage was significantly reduced by all six strains of lactic acid producing helpful bacteria tested with the exception of Streptococcus thermophilus.
There are many types of bacteria that live inside the mouth, nose, throat, and intestines of humans and animals. These bacteria get a place to live and feed while keeping other harmful microbes from taking up residence.
Certain stomach bacteria may work harmoniously with our immune system. There are billions of stomach bacteria, which are friendly or beneficial bacteria.
There are some friendly bacteria such as intestinal flora or micro flora which are good for human health. These healthy stomach bacteria are helpful to release many useful vitamins such as vitamin B and vitamin K, etc. The most important task that stomach bacteria do is to maintain normal pH level or acid level of human stomach.
Harmful bacteria
Certain bacteria act as pathogens and cause tetanus, typhoid fever, pneumonia, syphilis, cholera, food-borne illness and tuberculosis.
Streptococcus bacteria may cause small infections like strep throat and some serious diseases like pneumonia. Certain streptococci may be fatal.
Bacteria that usually live harmlessly in the body may cause infections when a person's resistance to disease is reduced in conditions such as AIDS (Acquired Immune Deficiency Syndrome).
Not all stomach bacteria are beneficial, some of the stomach bacteria enter the body through the mouth, and they can survive in the acidic conditions in the stomach and can cause serious diseases and can be fatal.
Campylobacter is a group of bacteria that can create illnesses in humans and is a common cause of food poisoning.Harmful bacteria in food cause botulism, which can cause paralysis or even death if even one millionth of the bacterium is ingested.
Yersinia pestis or bubonic plague, is a rod-shaped type of bacterium which is well known for its harmful nature. Bacteria-carrying fleas found on animals such as rats and mice transmit the bacteria that are believed to have caused the deaths of millions of people in human history.
Antibiotics are widely used to kill harmful bacteria. Washing hands with antiseptic soap will kill the bacteria. Don’t eat or drink from unhygienic
Sunday, September 28, 2008
DIFFERENT TYPES OF BACTERIA
Different Types of Bacteria
There are many types of bacteria which fall into different categories right from harmful to helpful bacteria and bacteria in different type of environments. Bacteria classification is mainly done based on morphology, condition required, DNA sequencing etc. Let us learn about the classification of bacteria.
Enlarge ImageWhat is bacteria?
Bacteria is a single-celled organism which can only be seen through microscope. Bacteria comes in different shapes and the size of bacteria is measured in micro-meter (which is a millionth part of a meter). Bacteria are found everywhere and in all type of environments.
There are numerous types of bacterial in the world. Before the invention of DNA sequencing technique, bacteria were mainly classified based on their shapes, which is also known as Morphology, biochemistry and staining (which is either Gram Positive or Gram Negative). Now a day along with the morphology, DNA sequencing is also used in order to classify bacteria. (DNA sequencing also helps in understanding relationship between two types of bacteria if they are related to each other despite of their shapes). Along with the shape and DNA sequence, other things such as their metabolic activities, conditions required for their growth, biochemical reactions (i.e. biochemistry as mentioned above), antigenic properties, and other characteristics are also helpful in classifying the bacteria.
There are various groups of bacteria, which belong to same family and are evolved from same bacteria (ancestor). However, each types of bacteria posses its own characteristics (those which are evolved after separation from the original specie).
Classification of Bacteria:
Bacteria are mainly classified into phylums (phylum is a scientific classification of organisms). For simplification, bacteria can be grouped into the following groups:
Bacteria classification based on shapes:
As already mentioned, before the advent of DNA sequencing, bacteria were classified based on their shapes and biochemical properties. Most of the bacteria belong to three main shapes: rod (rod shaped bacteria are called bacilli), sphere (sphere shaped bacteria are called cocci) and spiral (spiral shaped bacteria are called spirilla). Some bacteria belong to different shapes, which are more complex than the above mentioned shapes.
Aerobic and anaerobic bacteria:
Bacteria are also classified based on the requirement of oxygen for their survival. Bacteria those need oxygen for their survival are called Aerobic bacteria and bacteria those do not require oxygen for survival. Anaerobic bacteria cannot bear oxygen and may die if kept in oxygenated environment (anaerobic bacteria are found in places like under the surface of earth, deep ocean, and bacteria which live in some medium).
Gram Positive and Gram Negative bacteria:
Bacteria are grouped as ‘Gram Positive’ bacteria and ‘Gram Negative’ bacteria, which is based on the results of Gram Staining Method (in which, an agent is used to bind to the cell wall of the bacteria) on bacteria.
Autotrophic and heterotrophic bacteria:
This is one of the most important classification types as it takes into account the most important aspect of bacteria growth and reproduction. Autotrophic bacteria (also known as autotrophs) obtain the carbon it requires from carbon-dioxide. Some autotrophs directly use sun-light in order to produce sugar from carbon-dioxide whereas other depend on various chemical reactions. Heterotrophic bacteria obtain carob and/or sugar from the environment they are in (for example, the living cells or organism they are in).
Classification based on Phyla:
Based on the morphology, DNA sequencing, conditions required and biochemistry, scientists have classified bacteria into phyla:
1) Aquificae
2) Xenobacteria
3) Fibrobacter
4) Bacteroids
5) Firmicutes
6) Planctomycetes
7) Chrysogenetic
8) Cyanobacteria
9) Thermomicrobia
10) Chlorobia
11) Proteobacteria
12) Spirochaetes
13) Flavobacteria
14) Fusobacteria
15) Verrucomicrobia
Each phylum further corresponds to number of species and genera of bacteria. The bacteria classification includes bacteria which are found in various types of environments such as sweet water bacteria, ocean water bacteria, bacteria that can survive extreme temperatures (extreme hot as in sulfur water spring bacteria and extreme cold as in bacteria found in Antarctica ice), bacteria that can survive in highly acidic environment, bacteria that can survive highly alkaline environment, aerobic bacteria, anaerobic bacteria, autotrophic bacteria, heterotrophic bacteria, bacteria that can withstand high radiation etc.
There are many types of bacteria which fall into different categories right from harmful to helpful bacteria and bacteria in different type of environments. Bacteria classification is mainly done based on morphology, condition required, DNA sequencing etc. Let us learn about the classification of bacteria.
Enlarge ImageWhat is bacteria?
Bacteria is a single-celled organism which can only be seen through microscope. Bacteria comes in different shapes and the size of bacteria is measured in micro-meter (which is a millionth part of a meter). Bacteria are found everywhere and in all type of environments.
There are numerous types of bacterial in the world. Before the invention of DNA sequencing technique, bacteria were mainly classified based on their shapes, which is also known as Morphology, biochemistry and staining (which is either Gram Positive or Gram Negative). Now a day along with the morphology, DNA sequencing is also used in order to classify bacteria. (DNA sequencing also helps in understanding relationship between two types of bacteria if they are related to each other despite of their shapes). Along with the shape and DNA sequence, other things such as their metabolic activities, conditions required for their growth, biochemical reactions (i.e. biochemistry as mentioned above), antigenic properties, and other characteristics are also helpful in classifying the bacteria.
There are various groups of bacteria, which belong to same family and are evolved from same bacteria (ancestor). However, each types of bacteria posses its own characteristics (those which are evolved after separation from the original specie).
Classification of Bacteria:
Bacteria are mainly classified into phylums (phylum is a scientific classification of organisms). For simplification, bacteria can be grouped into the following groups:
Bacteria classification based on shapes:
As already mentioned, before the advent of DNA sequencing, bacteria were classified based on their shapes and biochemical properties. Most of the bacteria belong to three main shapes: rod (rod shaped bacteria are called bacilli), sphere (sphere shaped bacteria are called cocci) and spiral (spiral shaped bacteria are called spirilla). Some bacteria belong to different shapes, which are more complex than the above mentioned shapes.
Aerobic and anaerobic bacteria:
Bacteria are also classified based on the requirement of oxygen for their survival. Bacteria those need oxygen for their survival are called Aerobic bacteria and bacteria those do not require oxygen for survival. Anaerobic bacteria cannot bear oxygen and may die if kept in oxygenated environment (anaerobic bacteria are found in places like under the surface of earth, deep ocean, and bacteria which live in some medium).
Gram Positive and Gram Negative bacteria:
Bacteria are grouped as ‘Gram Positive’ bacteria and ‘Gram Negative’ bacteria, which is based on the results of Gram Staining Method (in which, an agent is used to bind to the cell wall of the bacteria) on bacteria.
Autotrophic and heterotrophic bacteria:
This is one of the most important classification types as it takes into account the most important aspect of bacteria growth and reproduction. Autotrophic bacteria (also known as autotrophs) obtain the carbon it requires from carbon-dioxide. Some autotrophs directly use sun-light in order to produce sugar from carbon-dioxide whereas other depend on various chemical reactions. Heterotrophic bacteria obtain carob and/or sugar from the environment they are in (for example, the living cells or organism they are in).
Classification based on Phyla:
Based on the morphology, DNA sequencing, conditions required and biochemistry, scientists have classified bacteria into phyla:
1) Aquificae
2) Xenobacteria
3) Fibrobacter
4) Bacteroids
5) Firmicutes
6) Planctomycetes
7) Chrysogenetic
8) Cyanobacteria
9) Thermomicrobia
10) Chlorobia
11) Proteobacteria
12) Spirochaetes
13) Flavobacteria
14) Fusobacteria
15) Verrucomicrobia
Each phylum further corresponds to number of species and genera of bacteria. The bacteria classification includes bacteria which are found in various types of environments such as sweet water bacteria, ocean water bacteria, bacteria that can survive extreme temperatures (extreme hot as in sulfur water spring bacteria and extreme cold as in bacteria found in Antarctica ice), bacteria that can survive in highly acidic environment, bacteria that can survive highly alkaline environment, aerobic bacteria, anaerobic bacteria, autotrophic bacteria, heterotrophic bacteria, bacteria that can withstand high radiation etc.
IMPORTANCE of fungi
IMPORTANCE of fungi
Act as decomposers.
cause disease in animals and plants.
essential for many industrial processes involving fermentation.
commercial production of many organic acids and certain drugs.
in manufacture of many antibiotics
acts as important research tools in the study of fundamental biological processes
Act as decomposers.
cause disease in animals and plants.
essential for many industrial processes involving fermentation.
commercial production of many organic acids and certain drugs.
in manufacture of many antibiotics
acts as important research tools in the study of fundamental biological processes
NUTRITION & METABOLISM
NUTRITION & METABOLISM
They grow best in dark moist habitats, but they are found wherever organic material is found. Most fungi are saprophytes. They release hydrolytic exoenzymes that digest external substrates, they then absorb the soluble products. They are chemo organoheterotrophs and derive carbon, oxygen and electrons from organic source.
They grow best in dark moist habitats, but they are found wherever organic material is found. Most fungi are saprophytes. They release hydrolytic exoenzymes that digest external substrates, they then absorb the soluble products. They are chemo organoheterotrophs and derive carbon, oxygen and electrons from organic source.
FUNGI STRUCTURE
Structure of Fungi
The main body of most fungi is made up of fine, branching, usually colourless threads called hyphae. Each fungus will have vast numbers of these hyphae, all intertwining to make up a tangled web called the mycelium.
The mycelium is generally too fine to be seen by the naked eye, except where the hyphae are very closely packed together. The picture on the left was taken through a microscope. The hyphae are magnified 100 times life size.
.
Some fungi, such as Honey Fungus, which is a parasite of woodland trees, have hyphae collected together into long cables, called rhizomorphs. Because there are so many hyphae packed together, they are easily seen, forming black 'bootlaces'. These can spread through a woodland infecting neighboring trees.
Fungal mycelium is mostly hidden from human view, not only because of its small size, but also as a result of its location. The tangled mycelial mass is usually hidden deep within its food sources, such as rotting matter in the soil, leaf litter, rotting wood, or dead animals. The mycelium remains undetected until it develops one or more fruiting bodies, containing the reproductive spores.
Fruiting bodies (such as mushrooms) are made up of thick collections of hyphae. They vary in size from small and insignificant, to large eye-catching structures.
They are usually produced at the surface of the food source, rather than hidden within it, to allow the spores to be shed and carried away by the wind, or by water, or animals. The fruiting bodies are usually the only indication we have that a fungus is present. Like icebergs, they represent a tiny fraction of the whole fungus, with most of it being hidden from view.
If you are looking for fungi in Britain, the best time to look is in the autumn. The fungal mycelia have then had a long, relatively warm period to grow extensively over the summer. With the coming of wetter weather in the autumn, damp warm conditions are created which are ideal for fungi to fruit. Many fungi have fruiting seasons in late summer to autumn. However, don't ignore the Spring. This is a good time to look for fungi such as Morels and other cup fungi. Little will be found in cold winter months with frosts, although Oyster mushrooms will continue to grow through most of the winter, as will Jew's Ear.
Fairy Rings
Fungal mycelia tend to grow in more or less circular shapes. This is because they grow by spreading out in all directions from a central point. This central point represents the location of the original spore which germinated to start the fungal mycelium. The mycelium will usually produce fruiting bodies on its outer edge. As a result, the fruiting bodies of fungi living hidden in the soil can sometimes be found in rings - the 'fairy rings' of children's stories.
The Clouded Agaric toadstool (right) is a good example of this. The fruiting bodies can often be found in rings, because they are produced on the outer growing edge of the circular, underground mycelium. The Clouded Agaric can be found in the leaf litter of both coniferous and deciduous woodland.
(image courtesy of Jeff Benn)
Another example is the 'Fairy Ring Toadstool' (Its scientific name is Marasmius oreades). This, in contrast to the Clouded Agaric, grows on grassy expanses such as lawns and golf courses. The fungus can be traced by the rings of dark green grass, with the mushrooms fruiting on the outer edge of the ring. The growth of the ring can be traced year on year. If there are no barriers, rings may grow outwards at up to 20 cm per year. This is a fungus which fruits early in the year, in the spring.
Giants of the natural world
Most people, if asked to name the largest organism on earth, come up with examples such as elephants, blue whales or giant trees, such as Redwoods. In fact, the largest living organism on this planet may well be a fungus!
In America, a single individual fungus, similar to the Honey Fungus already mentioned, was found to cover a staggering 2,200 acres of land. (This is 45 times bigger than the Woodland Education Centre in Offwell, for those of you who have visited the Centre before.)
Some of the oldest living organisms?
We tend to think of fungi as being short-lived, because the visible fruiting bodies which we see don't usually last very long. However, for the fungus to have reached this size, it must have been at least 2,400 years old. It would have been a mere youngster of 400 years old, at the time of Christ's birth.
The rings of Fairy Ring Toadstools found closer to home in Britain, possibly on your back lawn, can also grow to hundreds of meters in diameter, when they are likely to be at least a thousand years old.
Some lichens, which are a partnership between a fungus and an alga, have been estimated to be around 9000 years old!
Next time you find several fruiting bodies of one type of fungus growing on the ground, see if you can follow around in a circle and locate any more. The size of the circle will give you some indication of the size of the mycelium hidden beneath your feet. Bear in mind when you do this, that the fungus which is fruiting, will not be the only fungus hidden down there in the soil. In fact the ground beneath your feet will be absolutely seething with the mycelia of different fungi. We remain totally unaware of their presence simply because we can't see them.
The main body of most fungi is made up of fine, branching, usually colourless threads called hyphae. Each fungus will have vast numbers of these hyphae, all intertwining to make up a tangled web called the mycelium.
The mycelium is generally too fine to be seen by the naked eye, except where the hyphae are very closely packed together. The picture on the left was taken through a microscope. The hyphae are magnified 100 times life size.
.
Some fungi, such as Honey Fungus, which is a parasite of woodland trees, have hyphae collected together into long cables, called rhizomorphs. Because there are so many hyphae packed together, they are easily seen, forming black 'bootlaces'. These can spread through a woodland infecting neighboring trees.
Fungal mycelium is mostly hidden from human view, not only because of its small size, but also as a result of its location. The tangled mycelial mass is usually hidden deep within its food sources, such as rotting matter in the soil, leaf litter, rotting wood, or dead animals. The mycelium remains undetected until it develops one or more fruiting bodies, containing the reproductive spores.
Fruiting bodies (such as mushrooms) are made up of thick collections of hyphae. They vary in size from small and insignificant, to large eye-catching structures.
They are usually produced at the surface of the food source, rather than hidden within it, to allow the spores to be shed and carried away by the wind, or by water, or animals. The fruiting bodies are usually the only indication we have that a fungus is present. Like icebergs, they represent a tiny fraction of the whole fungus, with most of it being hidden from view.
If you are looking for fungi in Britain, the best time to look is in the autumn. The fungal mycelia have then had a long, relatively warm period to grow extensively over the summer. With the coming of wetter weather in the autumn, damp warm conditions are created which are ideal for fungi to fruit. Many fungi have fruiting seasons in late summer to autumn. However, don't ignore the Spring. This is a good time to look for fungi such as Morels and other cup fungi. Little will be found in cold winter months with frosts, although Oyster mushrooms will continue to grow through most of the winter, as will Jew's Ear.
Fairy Rings
Fungal mycelia tend to grow in more or less circular shapes. This is because they grow by spreading out in all directions from a central point. This central point represents the location of the original spore which germinated to start the fungal mycelium. The mycelium will usually produce fruiting bodies on its outer edge. As a result, the fruiting bodies of fungi living hidden in the soil can sometimes be found in rings - the 'fairy rings' of children's stories.
The Clouded Agaric toadstool (right) is a good example of this. The fruiting bodies can often be found in rings, because they are produced on the outer growing edge of the circular, underground mycelium. The Clouded Agaric can be found in the leaf litter of both coniferous and deciduous woodland.
(image courtesy of Jeff Benn)
Another example is the 'Fairy Ring Toadstool' (Its scientific name is Marasmius oreades). This, in contrast to the Clouded Agaric, grows on grassy expanses such as lawns and golf courses. The fungus can be traced by the rings of dark green grass, with the mushrooms fruiting on the outer edge of the ring. The growth of the ring can be traced year on year. If there are no barriers, rings may grow outwards at up to 20 cm per year. This is a fungus which fruits early in the year, in the spring.
Giants of the natural world
Most people, if asked to name the largest organism on earth, come up with examples such as elephants, blue whales or giant trees, such as Redwoods. In fact, the largest living organism on this planet may well be a fungus!
In America, a single individual fungus, similar to the Honey Fungus already mentioned, was found to cover a staggering 2,200 acres of land. (This is 45 times bigger than the Woodland Education Centre in Offwell, for those of you who have visited the Centre before.)
Some of the oldest living organisms?
We tend to think of fungi as being short-lived, because the visible fruiting bodies which we see don't usually last very long. However, for the fungus to have reached this size, it must have been at least 2,400 years old. It would have been a mere youngster of 400 years old, at the time of Christ's birth.
The rings of Fairy Ring Toadstools found closer to home in Britain, possibly on your back lawn, can also grow to hundreds of meters in diameter, when they are likely to be at least a thousand years old.
Some lichens, which are a partnership between a fungus and an alga, have been estimated to be around 9000 years old!
Next time you find several fruiting bodies of one type of fungus growing on the ground, see if you can follow around in a circle and locate any more. The size of the circle will give you some indication of the size of the mycelium hidden beneath your feet. Bear in mind when you do this, that the fungus which is fruiting, will not be the only fungus hidden down there in the soil. In fact the ground beneath your feet will be absolutely seething with the mycelia of different fungi. We remain totally unaware of their presence simply because we can't see them.
NEW FORM OF FUNGI
It's that time of year! Everything is coming up green, which means it's time to start planning your outdoor growing projects. Growing mushrooms on logs and stumps with our Mushroom Plug Spawn can be a great standalone project, or as a complement to any garden or landscape!
Our Outdoor Mushroom Patches™ are another great option for mushroom cultivation at home. We offer a wide variety of mushroom species (such as our Garden Giant Mushroom Patch™, pictured at right) for cultivation in beds of wood chips, soil or other material in your yard or garden.
2009 Seminar Dates Announced! We've put together our schedule of 2009 Cultivation and Mycorestorationsm Seminars and have made them available for signup. These classes will fill up fast—2008 is alread booked solid—so don't delay!
Our Outdoor Mushroom Patches™ are another great option for mushroom cultivation at home. We offer a wide variety of mushroom species (such as our Garden Giant Mushroom Patch™, pictured at right) for cultivation in beds of wood chips, soil or other material in your yard or garden.
2009 Seminar Dates Announced! We've put together our schedule of 2009 Cultivation and Mycorestorationsm Seminars and have made them available for signup. These classes will fill up fast—2008 is alread booked solid—so don't delay!
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