Lichens , types of lichens based on growth and habitat, importance of lichens, fungal habits and colonization strategies, Air borne fungi and micotoxins.

3. What is Lichen?
 A lichen is not a single organism but a symbiosis among
different organisms like fungus and a cyanobacterium
or algae.
 Cyanobacteria are also referred to as blue-green algae
despite the fact of being distinct from algae.
 The non-fungal part is known as photobiont that contains
chlorophyll.
 Many lichen partners include one photobiont and one
mycobiont which is not universal and there are lichens with
more than one photobiont partner.

4.  Mostly, lichens grow slowly.
 The one in which the phycobiont is a blue-green
bacterium has the ability to convert nitrogen gas into
ammonia.
 Some can reach the age of many centuries, mainly
the one living in stressful environments such as arctic
tundra or alpine.

7. There are various other types of
lichens. Based on their certain special
features, they are classified into
different types.
Based on their growth
1. Crustose Lichens
• Crustose lichens are flat, thin and
without any distinct lobes.
• They are usually found closely
attached to stones, rocks, barks and
the trunk of trees.
• Haematomma puniceum and
Graphic scripta are the best
examples of crustose lichens

8. 2. Foliose Lichens
The foliose lichens are more attractive
compared to other types of lichens. They
are flat shaped, broad, smooth and leaf-like
structures, which often resemble crinkled
and twisted leaves. It holds a distinct upper
and a lower surface. This type of lichens is
generally found attached to rocks and twigs
with the help of the rhizoid. Cetraria,
Cluiudhuria, Parmelia and Xanthoria are a
few examples of foliose lichens.

9. 3. Fruticose Lichens
These are the most important types of
lichens, which are thin and freely
branched. The fruticose lichens
constitute larger and attractive growths
standing out from the branches of
trees, foliage and rocks. Cladonia,
Ramalina and Usnea are the common
examples of fruticose lichens.

10. Based on their habitat:
1.Lignicolous. These types of lichens live in the woods.
2.Corticolous- These types of lichens live on the bark of trees.
3.Saxicolous- These types of lichens live on stones or rocks.
4.Marine. These types of lichens are found growing on the siliceous
rocks, near the shores of the sea.
5.Freshwater. These types of lichens are found growing on the hard
siliceous rocks, especially around the freshwater.
6.Terricolous- These types of lichens are found growing on the soil,
therefore also called the terrestrial lichens.

11. • Importance Of Lichens
• Lichens hold a great economic importance and are essential
for the environment in several ways.
• Some species of lichens are regarded with the conversion of
rocks into the soil, helps in the formation of soil, improving the
quality of the soil and also by enriching the soil required for the
plants’ growth.
• Lichens also plays an important role in the nitrogen cycle by
fixing nitrogen from the atmosphere.

12. • Lichens serve as an important source of food for humans across the
world. The Iceland moss is an important source of food in certain
parts of both Northern Europe and American continents.
• Based on the size of these lichens, Petrologists and Geologists are
able to study and find the age and other features of rocks and their
surfaces.
• Since ancient times, these species are well known for their various
colouring agents and dyes. They are a good source of natural dyes.
The litmus test, pH indicator and other dyes used in laboratories are
extracted from different species of lichens.
• Lichens also serve as a Biodegradation, by the degradation of
polyester, lead, copper, radionuclides and other pollutants, polluting
the planet earth.

13. They are also a great source of food for many aquatic
organisms and are widely used as anti-infective agents in
pharmaceutical industries to produce antibiotics, anti-
mycobacterial, antiviral, anti-inflammatory products.

16. • Fungus
• A fungus is any member of
the group of eukaryotic
organisms that includes
microorganisms such as
yeasts and molds, as well as
the more familiar
mushrooms.
• These organisms are
classified as a kingdom,
which is separate from the
other eukaryotic life
kingdoms of plants and
animals.

18. • Fungi are found all around the world and
grow in a wide range of habitats,
including deserts.
• Most grow on land (terrestrial)
environments, but several species live
only in aquatic habitats.
• Most fungi live in either soil or dead
matter, and many are symbionts of
plants, animals, or other fungi.

21. Colonization, or being colonized with C. auris, means that a person
has the fungus somewhere on their body but does not have an
infection or symptoms of infection.
What is fungal colonization-
o The fungal colonization is identified by the presence
of vegetative growth represented by ramifying hyphae.
o The colonization may be temporal and microscopic or
more extensive and obvious by sight and smell in
buildings with moisture problems.

22.  AM fungi release glomalins that
are certain metal sorble
glycoproteins which increase the
immobilization of toxic metals.
 Another protein is
metallothionine released by
certain AM fungi, which also
reduces the heavy metal toxicity
in soil.

23. There are two types of fungal colonization in fully myco-
heterotrophic orchids.
o In the majority of species, hyphal pelotons reminiscent of those seen
in green orchids are produced.
o These coils develop extensively in the outer cortical cells of the roots
but are only rarely found in the epidermal layer.
o In the second type of colonization, described by Burgeff (1932) as
ptyophagy, hyphal penetration of cells is restricted in the mid-cortex by
the formation of encapsulating ingrowths of the plant cell wall.

26. o What is airborne fungal spores?
o Airborne Fungal Spores In the
Outdoor Environment.
o Spores are released into the
environment from fungi growing as
saprophytes or parasites.
o Saprophytes are fungi that grow on
dead or decaying organic matter in
the soil or elsewhere in the
environment.

27. o Are airborne fungi harmful to humans?
o As mentioned earlier, airborne fungal spores can pose
major health and economic risks to humans, animal
populations and even plants.
o Therefore, there is need to be aware of the
composition and concentration of airborne fungal
spores to better control them.

28. Health Effects Associated with
Fungal Spores
Many fungi, if not all, are capable of causing allergic
responses in susceptible individuals. This happens
when one inhales excessive airborne spores.
Mycotoxins are toxic compounds but are only
produced under certain environmental conditions.
Some mycotoxins are carcinogenic and others can
damage the immune system. Though there has
been a great deal of interest in the past few years on
mycotoxins in indoor air little is known about their
negative health effects.

29. o While it is generally known that indoor fungi are potentially a
health hazard, there is no agreed upon level of airborne fungal
spores that signifies contamination and no health-based
guidelines exist.
o In absence of guidelines it is recommended that any indoor
fungal growth be removed and the moisture problem be fixed so
as to control fungal growth.