1.
NOSTOC
AND
SPIRULINA
PRESENTED BY,
Vivek kumar
M.SC MICROBIOLOGY
Bangalore university

2.
INTRODUCTION
 Nostoc is a filamentous cyanobacteria or Blue
green algae forms of both terrestrial and aquatic
habitats.
 It doesn’t occur in single filaments and grows in large
colonies.
 They are found in ponds ditches and damp soils.
 And few species lie in intercellular cavities of plants
like duck web.
 Nostac colony thus forms a mucilagenous lump or
thallus which occur floating or attached.
 Nostoc is capable of fixing Nitrogen.

3.
CLASSIFICATION OF NOSTOC
 DOMAIN- Bacteria
 PHYLUM- Cyanobacteria
 ORDER- Nostocales
 FAMILY- Nostacaceae
 GENUS-Nostoc

4.
ULTRA STRUCTURE
 It is blue green algae of filamentous form.
 Nostoc consists of many slender long & short inter
woven filaments which look like a chain of beads .
 Each filaments is unbranched & consists of row of
rounded or oval cells.
 There is a often a gelatinous sheath covering each
filament is known as mucligenous sheath.
 Each cell is differentiated into two regions called
chromoplasm(the outer region is blue green
poigmented) & the inner colourless region called
centroplasm.

5.
 The filament increases in length by cell division in one
plane only.
 Some enlarged vegetative cells with thickened walls &
transparent contents are seen to occur at frequent
intervals & also at the ends are called heterocysts.
 A pore is present to each pole of the heterocyst
maintaining cytoplasmic connection with adjoining cells .
 There is one pore at the terminal heterocyst
 At the later stage the pore is closed by a button like
thickening of the cell wall called polar molecules.

6.
REPRODUCTION
 Nostoc reproduces vegetatively & asexually.
 Sexual reproduction is absent.
 All the filaments of the colony reproduce
simultaneously.
 The sexual reproduction is totally absent nostoc
reproduce only vegetatively by following methods
 Framentation
 Horomogonia
 Akinetes
 Heterocysts
 Fusion

7.
FRAGMENTATION
 By mechanical , physiological or by the colony breaks
into 2 or more fragments.
 Each of fragments is capable to develop into new colony
of nostoc.

8.
HORMOGONIA
 It is one of the very common methods of
reproduction in nostoc.
 The filaments may breaks into a number of pieces
because of the decay of ordinary vegetative cells or
owing to the appearance of heterocyst.
 The detailed structure of vegetative cell of nostoc is
similar to that discused in the general account of
myxophycean cell.

9.
ASEXUALLY REPRODUCTION
AKINETES
 An akinete is thick walled dormant cell derived
enlargement of vegetative cell.
 These are also called as resting spores or
arthrospores & formed by many species of nostoc.
 Large a mount of reserve food materials along with
the cyanophcin granules is being stored by the
akinetes.
 In favourable conditions they directly or indirectly
giving rise to new filaments.
 The contents of akinetes divide into bits prior to
germination .

10.
HETEROCYST
 Rarely the heterocysts become functional and
germinates to form a new filament in a few species
like N.Commcene.
 During germination the heterocyst divide first into 2
celled and then into 4 celled which ruptures the
outer wall comes out and develops into a new
filament.
 Heterocysts are specalized Nitrogen fixing cells.
 They are formed during nitrogen starvation by
filamentous Cyanobacteria.
 They are of same shape as of vegetative cells and
are mutually independent.

11.
SIGNIFICANCE
 Nostoc colony are rich in nitrogenous substances.
 Hence they are used as food in China and Brazil.
 Nostoc colonies increases nitogen contents of the
soil and are often used as fertilizer to increase the
crop productivity.(such as paddy).
 Nostoc is capable of fixing nitogen and grows
rapidly.
 Nostoc is used,because of these properties,in
reclamation of usuar(alkaline and saline) and
barren soil.

12.
SPIRULINA
 INTRODUCTION
 ULTRASTRUCTURE
 REPRODUCTION
 SIGNIFICANCE

13.
INTRODUCTION
 Spirulina is a filamentous micro-Cyanobacteria and are
photoautotrophs.
 It is composed of cylindrical cells arranged in
unbranched,helicoidal trichomes.
 They are found in a variety environment such as Soil,
Sand, Marshes,Brackish water ,Sea,Water and Fresh
water.
 The planktonic species of spirulina occurs frequently in
Shallow,alkaline lake of high salinity in the entire
African continent and in South America.
 Spirulina a micro-Cyanobacterium posses high value
biochemical constituents that find applications in areas
like Health Foods and Therapeutics.
 Spirulina species has been produced commercially all
over the world due to its high contents of proteins
(upto 70%).

14.
ULTRASTRUCTURE
 Spirulina is a Filamentous Cyanobacteria and cell
wall is formed by 4 numbered layers.
 The layers are L1, L11, L111 and L1V and these
layers are weak except layer L11.
 Because L11 is made up of peptidoglycon.
 Hence the substance that gives the wall its rigidity.
 The L11 layer contains b-1, 2-glucan, a
polysaccaride and not very digestable by
human beings.

15.
 The protein and lipopolysaccharide nature of the L11
layer are favourite reasons for the easy human digestion
of spirulina.
 In spirulina- Chlorophylla, carotenes and phycobilisarus,
which contains phylocyanin (blue pigment) are located in
the thylakoid systems/photosynthetic lamellar.
 The inter thylakoid space is limited by the presence of
electronically transparent protein Gas vesicles, with the
cylindrical form the gives spirulina its floating capacity.

16.
REPRODUCTION
 In spirulina Reproduction takes place asexually by
Binary Fission.
 Sexual reproduction is absent.
BINARY FISSION
 It means a single cell is splitting into 2 cells.
 It is is a type of asexual reproduction where inside the
cell a division develops on the middle of the organisms.
 The division eventually completely divides the bacterium
in half and known as Cytokinesis.
 Each cell is now Gentically identical offsprings.
 In binary fission ,it results into two identical
daughter cells.

17.
SIGNIFICANCE
 Spirulina is a natural (algae)/Cyanobacteria.
 Spirulina is a ideal food and dietary supplement for
21st Century by Food and Agriculture Organization
(FAD).
 Spirulina powder is incredibily high in proteins i.e
more than 60% and good source of antioxidants,
B-Vitamin and other Nutrients.
 Spirulina is added to numerous types of pet foods.

18.
 It is largely made up of proteins and essential
Amino Acids and high Natural iron contents.
 Spirulina is also used as Antiviral because it has all
biochemicals in its constitution. That can build a
Healthy Immune System which scavengers free
radicals as well as cpds.
 Extracted from Arthrospira have inhibitory activity
against a wide range of viruses such as HIV-1, HSV-
1, HSV-2 , HCMV, Influenza Type-A ,Measles.
 Spirulina is also used as Anticancer Agent and also
used as Capsules and Tablets as Nutrients and for
Weight loss also.
 Hence spirulina has many Beneficial Facts.

19.
THANK YOU