5. Fungi are eukaryotic organisms that include microorganisms such as yeasts, moulds and mushrooms. These organisms are classified under kingdom fungi.
The organisms found in Kingdom fungi contain a cell wall and are omnipresent. They are classified as heterotrophs among the living organisms.
Kingdom Fungi
To name a few – the appearance of black spots on bread left outside for some days, the mushroomsand the yeast cells, which are commonly used for the production of
beer and bread are also fungi. They are also found in most skin infections and other fungal diseases.
If we observe carefully, all the examples that we cited involve moist conditions. Thus, we can say that fungi usually grow in places which are moist and warm enough to
support them.
Let us have a detailed overview of the structure, classification and characteristics of fungi.
StructureofFungi
The structure of fungi can be explained in the following points:
Almost all the fungi have a filamentous structure except the yeast cells.
They can be either single-celled or multicellular organisms.
Fungi consist of long thread-like structures known as hyphae. These hyphae together form a mesh-like structure called mycelium.
Fungi possess a cellwall which is made up of chitin and polysaccharides.
The cell wall comprises a protoplast, which is differentiated into other cell parts such as cell membrane, cytoplasm, cell organelles and nuclei.
The nucleus is dense, clear, with chromatin threads. The nucleus is surrounded by a nuclear membrane.
6. Following are the important characteristics of fungi:
Fungi are eukaryotic, non-vascular, non-motile and heterotrophic organisms.
They may be unicellular or filamentous.
They reproduce by means of spores.
Fungi exhibit the phenomenon of alternation of generation.
Fungi lack chlorophyll and hence cannot perform photosynthesis.
Fungi store their food in the form of starch.
Biosynthesis of chitin occurs in fungi.
The nuclei of the fungi are very small.
The fungi have no embryonic stage. They develop from the spores.
The mode of reproduction is sexual or asexual.
Some fungi are parasitic and can infect the host.
Fungi produce a chemical called pheromone which leads to sexual reproduction in fungi.
Examples include mushrooms, moulds and yeast.
7. Fungal infections, or mycosis, are diseases caused by a fungus
(yeast or mold). Fungal infections are most common on your
skin or nails, but fungi (plural of fungus) can also cause
infections in your mouth, throat, lungs, urinary tract and
many other parts of your body.
8. Fungal infections on or in your skin can look red, swollen or
bumpy. They can look like a rash or you might be able to see a
lump under your skin. Fungal infections in your nails can
make them discolored (yellow, brown or white), thick or
cracked. Fungal infections in your mouth or throat can cause
a white coating or patches.
9. Anyone can get a fungal infection, especially ones that affect your skin or nails. Fungal
infections are more common in places on your body that trap moisture or have a lot of
friction. You’re at higher risk for infection, especially severe ones, if you have poor circulation
or diabetes, or if you have a weakened immune system from:
HIV/AIDS.
Cancer or cancer treatments.
Immunosuppressant medications (for autoimmune conditions or organ, stem cell or bone
marrow transplants).
10. Fungal infections can be on the surface of your skin, nails
or mucous membranes (superficial or mucocutaneous),
underneath your skin (subcutaneous) or inside other
organs of your body — like your lungs, brain or heart
(deep infection).
11. Superficial fungal infections affect your nails, skin and mucous membranes (like your mouth, throat or vagina).
Examples of superficial fungal infections include:
Ringworm(dermatophytosis). A group of fungi that live off of skin, hair and nail cells (dermatophytes) cause
ringworm. They can infect your feet (tinea pedis/athlete’s foot), your groin and inner thighs (tinea cruris/jock
itch), your scalp (tinea capitis), your hands (tinea manuum), your facial hair and skin around it (tinea barbae)
and other parts of your body (tinea corporis).
Onychomycosis. Many types of fungi cause infections of your fingernails or toenails (onychomycosis). This can
cause discolored and cracked nails.
Candidiasis.Candida (usually Candida albicans) causes skin and mucous membrane (mucocutaneous) infections
called candidiasis. These include oral thrush, some types of diaper rash, vaginal yeast infections (vulvovaginitis),
esophageal candidiasis and candidal intertrigo.
Tineaversicolor/pityriasisversicolor. The fungus Malassezia causes skin discoloration called tinea versicolor or
pityriasis versicolor.
12. You can get a fungal infection under the surface of your skin (subcutaneous) if fungus gets into a cut or wound, usually through injury while
working with plants (like a scratch from a thorn). They cause rashes, ulcers and other symptoms on your skin.
Subcutaneous fungal infections are more common in tropical and subtropical areas of the world. Examples include:
Sporotrichosis(rosegardener’sdisease). Sporothrix fungus causes sporotrichosis. You can also get sporotrichosis in your lungs or other parts of
your body.
You can get a fungal infection under the surface of your skin (subcutaneous) if fungus gets into a cut or wound, usually through injury while
working with plants (like a scratch from a thorn). They cause rashes, ulcers and other symptoms on your skin.
Subcutaneous fungal infections are more common in tropical and subtropical areas of the world. Examples include:
Sporotrichosis(rosegardener’sdisease). Sporothrix fungus causes sporotrichosis. You can also get sporotrichosis in your lungs or other parts of
your body.
Chromoblastomycosis. Many different fungi can cause chromoblastomycosis. It can cause a long-lasting (chronic) skin infections. Rarely, it
spreads to other parts of your body.
Eumycetoma. Many different fungi can cause eumycetoma. It most commonly affects your feet.
13. Doctors usually scrap pieces of the affected skin area or toenails fungus to examine under a
microscope. These detections lead to the result that proves if it is caused by fungal infection or
due to any other diseases. Toenail or fingernail infections may take months to recover with
proper medications. All the infections like jock itch, yeast infections, and ringworms are easily
curable if treated correctly. Fungal ointments and creams are easily available in the drug store
that can help you cure the infection.
Fungal infections are treated with prescription creams, but serious infections need more
medications and care. Fungal infection treatments and precautions can also avoid fungal skin
infections, and listening to a doctor early can also help. Most cases are easily treated by working
directly with a doctor.
14. Many of us know fungi as disease-causing organisms or as mushrooms that grow in the lawn or forests. However, these examples
are only a few members of the huge groups of fungi, which has many thousands of members. For instance, the yeast, that
scientists call Saccharomyces cerevisiae, is a single-celled organism used to make bread and pizza dough rise, or to ferment wine
and beer, is a fungus . We can also obtain medicines, such as antibiotics, from certain fungi. These are examples of how fungi can
be useful to us. However, there are also fungi that can attack plants, causing plant diseases. Disease-causing organisms, including
fungi, are called pathogens
An agent (e.g., virus, bacteria, or fungi) that can cause a disease to a living organism.
. Pathogens of plants use their plant hosts for food, or for a place to reproduce themselves, causing damage to the plant. Fungal
pathogens are extremely dangerous and may cause the loss of crop harvests or, in the most serious cases, the death of the plants.
Fungi can also negatively affect the quality of crops, causing an accumulation of toxins within the plants. The toxins produced by
some fungi are dangerous for humans and animals.
15. When the climate conditions are right, fungal pathogens can grow exponentially and devastate crops. For instance, a
fungus called botrytis bunch rot can destroy more than 80% of strawberry flowers and fruits. The same fungus can
also attack tomatoes, affecting up to 70% of the plants and causing premature death. This fungus can infect more
than 1,400 different species of plants, including grapes, raspberries, blackberries, beans, lettuce, and flowers, such as
roses, gerbera, daisies, and orchids. It has been estimated that fungal pathogens cause the loss of hundreds of
billions of US dollars across the world every year. Humans can directly suffer the consequences of fungi attacks. For
instance, the Great Famine in Ireland (1845–1852), which caused the death of 1 million people, was triggered by a
pathogen called potato late blight fungus that destroyed potatoes, the principal source of food for poor people at the
time.
16. Symptoms are the visible effects of a disease caused by a pathogen. Different fungi can attack
different plants and plant organs, so fungal infections cause an enormous range of disease
symptoms, such as color and shape changes, rotting, wounds, and wilting (Figure 3). Color
changes can appear as leaf yellowing and can be accompanied by changes in leaf shape. Cell
death causes parts of the plant to decompose and turns plant tissues into a dark color; this can
appear as spots on leaves, or rotten spots on fruits. Mildews and molds are not disease symptoms
but are the visible parts of the fungus on the plant surface, including the mycelium and spores.
Some fungal diseases cause small wounds on plant organs that look like scabs. The disease
symptoms help us to figure out which fungal disease is affecting the plant, so that we can apply
the right defensive tools to treat the infection.
17.
18. Plants cannot communicate with us, so sometimes it is difficult to understand when they are sick. Furthermore, once
we see disease symptoms on plant tissues, it is impossible to heal the plants. We can only reduce the damage by
decreasing the spread of the disease to neighboring, healthy organs and plants. This means that prevention is the
most effective way to manage plant diseases. To prevent fungal diseases, several methods can be used: the cultivation
of fungus-resistant crop varieties
A specific group of a plant selected by humans for its characteristics (e.g., fruit quality or resistance to diseases).
, the use of appropriate farming practices, and the use of fungicides, which are chemical substances able to kill fungi.
A resistant crop could have various strategies to overcome fungal attack and development, like stronger physical
barriers or the production of anti-fungal compounds [5]. Unfortunately, a resistant crop is only resistant to a limited
range of fungal pathogens, and sometimes the fungus can overcome the plant’s resistance. However, the proper use of
fungus-resistant crops can reduce the issues caused by plant pathogens.
19. Fungi can affect animals in several ways. A mycosis is a fungal disease that results from infection and direct damage.
Fungi attack animals directly by colonizing and destroying tissues. Mycotoxicosis is the poisoning of humans (and
other animals) by foods contaminated by fungal toxins (mycotoxins). Mycetismus describes the ingestion of
preformed toxins in poisonous mushrooms. In addition, individuals who display hypersensitivity to molds and
spores develop strong and dangerous allergic reactions. Fungal infections are generally very difficult to treat because,
unlike bacteria, fungi are eukaryotes. Antibiotics only target prokaryotic cells, whereas compounds that kill fungi
also harm the eukaryotic animal host.
Many fungal infections are superficial; that is, they occur on the animal’s skin. Termed cutaneous (“skin”) mycoses,
they can have devastating effects. For example, the decline of the world’s frog population in recent years may be
caused by the fungus Batrachochytrium dendrobatidis, which infects the skin of frogs and presumably interferes
with gaseous exchange.
20. This is a chronic disease of horses caused by a fungus Histoplasma (Crypto- coccus)
farciminosus and characterised by inflammation and suppuration of the cutaneous
and subcutaneous lymphatic vessels and glands. It gains entry through a wound or
abrasion either on the skin or of a mucous surface. The disease is spread by
harness, grooming tools etc. which have come in contact with diseased animals. The
parasite shows considerable vitality outside the animal body.
21. This is a parasitic skin disease of man and animals of a contagious nature and
is caused by the fungi belonging to the genera Microsporon and
Trichophyton. The organisms belong to the two genera of fungi Imperfecti, a
large group of fungi whose life history is not completely known. It must be
rememberedthat two important contributory causes of ringwormare:
(1) Over-crowding of animals into unhygienic, badly ventilated buildings and
(2) General debility due to under-nourishment. There is of course seasonal
variation.
22. This is a disease of mammals and birds produced by the growth of the fungus
Aspergillus in the tissues of the body. The most commonly affected is the
respiratory tract but it has also been seen in ears, mouth, throat and liver. It runs a
slow course and often mistaken for tuberculosis. The disease is produced by fungus
Aspergillis where it causes a necrosis or death of cells and formation of small
abscesses. Within the body, they grow out hyphae and produce more spores and
these spread the infection further.
23. Benign cases may heal spontaneously but malignant cases resist all forms of treatment. In general,
exposure to direct sunlight, dry air, good feeding with much nitrogenous food and rest have a
favourable influence on the disease and this explains why in tropical and subtropical regions,
recovery is’ more frequent than in other countries. Treatment consists in surgical excision of all
affected nodes, cords and ulcers with antiseptic dressing. Ulcers treated locally with a.2% methylene
blue solution hastens their healing.
Injectionof thefollowingis reportedto haveexcellentresults:
This is given intravenously once a day for 8 days and after a gap of one week for another 8 days.
