This document provides an introduction to cyanobacteria, including:
1) Cyanobacteria are prokaryotic organisms that were originally misclassified as algae. They were the first organisms to evolve oxygenic photosynthesis.
2) Cyanobacteria are found in diverse aquatic and terrestrial habitats worldwide. They can form thick mats and blooms under suitable conditions.
3) Cyanobacteria have a variety of morphologies and play important ecological roles while also having applications in industry, agriculture and biotechnology. However, some species can produce toxins harmful to animals and humans.
The plant body in algae is always a thallus. It is not differentiated in root, stem and leaves. Algae range in size from minute unicellular plants (less than 1 µ in diameter in some planktons) to very large highly differentiated multicellular forms e.g., some sea-weeds.
Their forms may be colonial (loose or integrated by inter-connections of protoplasmic strands), filamentous (branched or un-branched), septate (branched or un-branched), non-septate or branched, multinucleate siphonaceous tube where the nuclear divisions occur without usual septa formation.
Introduction,In some fungi ,true sexual cycle comprising of nuclear fusion and meiosis is absent.
These fungi derive the benefits of sexuality through a cycle know as parasexuaL cycle.
First Reported by- Gudio Pontecorvo and J.A.Roper(1952)
Parasexual cycle was reported in
Aspergillus nidulans,the imperfect stage of Emericella nidulans.
Since then parasexual cycle has been discovered not only in several members of Deutromycetes but also in fungi belonging to Ascomycetes and Basidiomycetes.
DEFINETION - Parasexuality is defined as a cycle in which Plasmogamy, Karyogamy and Meiosis [Haploidization] take place in sequence but not at a specified time or at specified points in the life cycle of an organism.
Generally parasexual cycle occurs in those fungi in which true sexual cycle does not take place.
Parasexualcycle also know as Somatic recombination. PASEXUALITY ALSO REPORTED IN SOME ORGANISMS- Aspergillus nigar, Penicillium crysogenum, STEPS OF PARASEXUAL CYCLE - 1) ESTABLISHMENT OF HETEROKARYOSIS, 2) Formation of Heterozygous DIPLOIDS, 3) occasional mitotic crossing-over during multiplication of diploid nuclei, 4)occasional haplodization through aneuploidy , COMPARISION BETWEEN SEXUAL AND PARASEXUAL CYCLE, IMPORTANCE OF PARASEXUALITY, C0NCLUSION
The algae reproduce by vegetative, asexual, and sexual methods. Vegetative reproduction is by fragmentation, where each fragment develops into a thallus. Asexual reproduction is by the production of flagellated zoospores which on germination give rise to new plants.
Algae are chlorophyll bearing autotrophic bodies with thalloid plant body. Thallus may be unicellular to multicellular, microscopic or macroscopic in structure.
A chemical substance that is produced in one portion of an organism and moves by diffusion or transport to another portion of same individual or to other individual of same species where it induce specific response is called a hormone.
About 20,000 species.
Eukaryotic cell and contain all the membrane bound organelles.
Thallus is green due to the presence of green pigment chlorophyll.
Chlorophyll is contained in chloroplast.
Pyrenoids embedded in chloroplast.
Cytoplasm contains vacuoles.
Motile cell of primitive forms contains eye spot or stigma.
Reserve carbohydrates are in the form of starch.
Cell wall invariably contains cellulose.
Produce motile reproductive bodies generally with two or four flagella.
Most are aquatic but some are subarial.
Several species of ulvales and siphonales are marine.
Some strains of chlorella are thermophilic.
Species of chlamydomonas and some chlorococcales occur in snow.
Coloechaete nitellarum is endophytic.
Cephaleuros is parasitic – cause ‘red rust of tea’.
Live epizoically on or endozoically within the bodies of lower animals – chlorella is found in hydra; chlorella beneath the scales of fish; characium on the antennae of mosquito.
Green algae in assosciation with the fungi constitute lichens.
Chlamydomonas is unicellular, motile green algae. In this presentation the systematic position, occurrence, structure and different types of reproduction is being explained. palmella stage in vegetative reproduction is one of the outstanding character found among the other algae.
Algae are a diverse group of aquatic organisms that have the ability to conduct photosynthesis. Certain algae are familiar to most people; for instance, seaweeds (such as kelp or phytoplankton), pond scum or the algal blooms in lakes.
Heterothallic species have sexes that reside in different individuals. . The term is applied particularly to distinguish heterothallic fungi, which require two compatible partners to produce sexual spores, from homothallic ones, which are capable of sexual reproduction from a single organism.
Cyanobacteria as a Biofertilizer (BY- Ayushi).pptxAyushiKardam
Cyanobacteria, also known as “blue-green algae”.
They are aquatic and photosynthetic, that is, they live in the water, and can manufacture their own food. Because they are bacteria, they are quite small and usually unicellular, though they often grow in colonies large enough to see.
They are the most abundant group of organisms on the earth. They are autotrophic and found in a diverse environment, especially in the marine and freshwater.
La botánica (del griego βοτάνη, 'hierba') o fitología (del griego φυτόν, 'planta' y λόγος, 'tratado') es la rama de la biología que estudia las plantas bajo todos sus aspectos, incluyendo la descripción, clasificación, distribución, identificación, estudio de la reproducción, fisiología, morfología, relaciones recíprocas, relaciones con los otros seres vivos y efectos provocados sobre el medio en el que se encuentran.
The plant body in algae is always a thallus. It is not differentiated in root, stem and leaves. Algae range in size from minute unicellular plants (less than 1 µ in diameter in some planktons) to very large highly differentiated multicellular forms e.g., some sea-weeds.
Their forms may be colonial (loose or integrated by inter-connections of protoplasmic strands), filamentous (branched or un-branched), septate (branched or un-branched), non-septate or branched, multinucleate siphonaceous tube where the nuclear divisions occur without usual septa formation.
Introduction,In some fungi ,true sexual cycle comprising of nuclear fusion and meiosis is absent.
These fungi derive the benefits of sexuality through a cycle know as parasexuaL cycle.
First Reported by- Gudio Pontecorvo and J.A.Roper(1952)
Parasexual cycle was reported in
Aspergillus nidulans,the imperfect stage of Emericella nidulans.
Since then parasexual cycle has been discovered not only in several members of Deutromycetes but also in fungi belonging to Ascomycetes and Basidiomycetes.
DEFINETION - Parasexuality is defined as a cycle in which Plasmogamy, Karyogamy and Meiosis [Haploidization] take place in sequence but not at a specified time or at specified points in the life cycle of an organism.
Generally parasexual cycle occurs in those fungi in which true sexual cycle does not take place.
Parasexualcycle also know as Somatic recombination. PASEXUALITY ALSO REPORTED IN SOME ORGANISMS- Aspergillus nigar, Penicillium crysogenum, STEPS OF PARASEXUAL CYCLE - 1) ESTABLISHMENT OF HETEROKARYOSIS, 2) Formation of Heterozygous DIPLOIDS, 3) occasional mitotic crossing-over during multiplication of diploid nuclei, 4)occasional haplodization through aneuploidy , COMPARISION BETWEEN SEXUAL AND PARASEXUAL CYCLE, IMPORTANCE OF PARASEXUALITY, C0NCLUSION
The algae reproduce by vegetative, asexual, and sexual methods. Vegetative reproduction is by fragmentation, where each fragment develops into a thallus. Asexual reproduction is by the production of flagellated zoospores which on germination give rise to new plants.
Algae are chlorophyll bearing autotrophic bodies with thalloid plant body. Thallus may be unicellular to multicellular, microscopic or macroscopic in structure.
A chemical substance that is produced in one portion of an organism and moves by diffusion or transport to another portion of same individual or to other individual of same species where it induce specific response is called a hormone.
About 20,000 species.
Eukaryotic cell and contain all the membrane bound organelles.
Thallus is green due to the presence of green pigment chlorophyll.
Chlorophyll is contained in chloroplast.
Pyrenoids embedded in chloroplast.
Cytoplasm contains vacuoles.
Motile cell of primitive forms contains eye spot or stigma.
Reserve carbohydrates are in the form of starch.
Cell wall invariably contains cellulose.
Produce motile reproductive bodies generally with two or four flagella.
Most are aquatic but some are subarial.
Several species of ulvales and siphonales are marine.
Some strains of chlorella are thermophilic.
Species of chlamydomonas and some chlorococcales occur in snow.
Coloechaete nitellarum is endophytic.
Cephaleuros is parasitic – cause ‘red rust of tea’.
Live epizoically on or endozoically within the bodies of lower animals – chlorella is found in hydra; chlorella beneath the scales of fish; characium on the antennae of mosquito.
Green algae in assosciation with the fungi constitute lichens.
Chlamydomonas is unicellular, motile green algae. In this presentation the systematic position, occurrence, structure and different types of reproduction is being explained. palmella stage in vegetative reproduction is one of the outstanding character found among the other algae.
Algae are a diverse group of aquatic organisms that have the ability to conduct photosynthesis. Certain algae are familiar to most people; for instance, seaweeds (such as kelp or phytoplankton), pond scum or the algal blooms in lakes.
Heterothallic species have sexes that reside in different individuals. . The term is applied particularly to distinguish heterothallic fungi, which require two compatible partners to produce sexual spores, from homothallic ones, which are capable of sexual reproduction from a single organism.
Cyanobacteria as a Biofertilizer (BY- Ayushi).pptxAyushiKardam
Cyanobacteria, also known as “blue-green algae”.
They are aquatic and photosynthetic, that is, they live in the water, and can manufacture their own food. Because they are bacteria, they are quite small and usually unicellular, though they often grow in colonies large enough to see.
They are the most abundant group of organisms on the earth. They are autotrophic and found in a diverse environment, especially in the marine and freshwater.
La botánica (del griego βοτάνη, 'hierba') o fitología (del griego φυτόν, 'planta' y λόγος, 'tratado') es la rama de la biología que estudia las plantas bajo todos sus aspectos, incluyendo la descripción, clasificación, distribución, identificación, estudio de la reproducción, fisiología, morfología, relaciones recíprocas, relaciones con los otros seres vivos y efectos provocados sobre el medio en el que se encuentran.
Cyanophyceae or Myxophyceae is a group of prokaryotic organisms, commonly called blue-green algae. Since their cellular organization is typically prokaryotic, the current trend is to consider them not as true algae, but as monerans. Accordingly, they are now grouped under Sub-kingdom Cyanobacteria of Kingdom Monera. The name Cyanophyceae or blue-green algae denotes the presence of the blue-green pigment phycocyanin; the name Myxophyceae refers to the presence of the carotenoid pigment myxoxanthin.
(i) Most members are filamentous forms, but some are unicellular and some others are colonial. (ii) Filamentous forms consist of a linear row of cells, called trichome, enclosed by a common sheath. Trichome may have some large and thick-walled cells, called heterocysts. (iii) Cells are typically prokaryotic, without membrane-bound cell organelles and an organized nucleus.
(iv) Chief pigments are chlorophyll-a, phycocyanin, allophycocyanin, phycoerythrin, myxoxanthin, oscillaxanthin, ß-carotene and leutein. (v) Reserve food include cyanophysean starch (glycogen) and cyanophysin (a protein). (vi) Protoplast is differentiated into outer chromoplasm and inner centroplasm. (vii) Flagella are altogether absent at any stage. (viii) Reproduction is asexual
Cyanobacteria are important in the nitrogen cycle.
Cyanobacteria are very important organisms for the health and growth of many plants. They are one of very few groups of organisms that can convert inert atmospheric nitrogen into an organic form, such as nitrate or ammonia.
Cyanobacteria are photosynthetic group of bacteria that can fix atmospheric nitrogen essential for aminoacid biosynthesis. Earlier they were called as blue green algae. Now that name is not used because they are not belongs to the algae.
Cyanobacteria are photosynthetic group of bacteria that can fix atmospheric nitrogen essential for aminoacid biosynthesis. Earlier they were called as blue green algae. Now that name is not used because they are not belongs to the algae.
Algae plays a vital role in our Food system but we're not aware of the benefits of Algae, see weed, nori or any other aquatic plants that we can incorporate or take as Food in orders to nourish our body n developmental factors with numerous nutrients and minerals in it.
If you want to explore the role of Cyanobacteria in soil fertility in general & Azolla-Anabena association in particular, you can visit this PowerPoint Presentation.
The term "algae" refers to a class of mostly watery, photosynthetic, and nucleus-bearing organisms that lack the real roots, stalks, and leaves of plants as well as their specialized multicellular reproductive systems.
What are Algae?
In addition to ponds, brackish waterways, and even snow, seaweed may be found in rivers, lakes, seas, and ponds. seaweed are often green, although they can also be found in other hues. For instance, the carotenoid pigments and chlorophyll present in the seaweed that live in snow give the surrounding snow its unique red colo The name "alga" refers to a huge and extraordinarily diversified class of eukaryotic, photosynthetic lifeforms. These species are not linked to one another (polyphyletic) since they do not have a common ancestor.
Giant kelp and brown algae are two examples of multicellular algae. Examples of unicellular organisms include dinoflagellates, euglenophytes, and diatoms.
Since most algae need a moist or wet environment to thrive, they can be found everywhere near or inside water bodies. They have anatomical similarities with the land plants, a significant group of photosynthetic creatures. The distinctions stop there since seaweed lack many of the structural elements that are generally seen in plants, such as real stems, shoots, and leaves. Additionally, they lack the vascular tissues needed to transport vital nutrients and water throughout their bodies.
Characteristics of Seaweed
Plants and animals share specific general properties of seaweed.
Eukaryotic cells make up seaweed. Algae, for example, may photosynthesize like plants and have specialized cell organelles like centrioles and flagella that are exclusively found in animals. Manna's, cellulose, and Galatians make up the algal cell walls. Some of the general characteristics of algae are listed below.
Seaweed are photosynthetic organisms
Seaweed can be either unicellular or multicellular organisms
Seaweed lack a well-defined body, so, structures like roots, stems or leaves are absent
seaweed are found where there is adequate moisture.
Reproduction in algae occurs in both asexual and sexual forms. Asexual reproduction occurs by spore formation.
Seaweed are free-living, although some can form a symbiotic relationship with other organisms.
Types of Saweed
Algae come in a variety of varieties. But these are a few of the more well-known kinds:
Red Scum
It is a peculiar species that is also known as Rhodophyta, and it may be found in both freshwater and marine settings. The distinctive red hue of the algae is caused by the pigments phycocyanin and phycoerythrin. There are other pigments that give things their green hue, such chlorophyll a. But neither beta-carotene nor chlorophyll B are present.
Green Algae
It is a large, loosely organized collection of scum that include the essential pigments for photosynthetic activity, chlorophylls A and B, as well as auxiliary pigments like xanthophyll's and beta carotene.
Green scum car
The term "algae" refers to a class of mostly watery, photosynthetic, and nucleus-bearing organisms that lack the real roots, stalks, and leaves of plants as well as their specialized multicellular reproductive systems.
What are Algae?
In addition to ponds, brackish waterways, and even snow, seaweed may be found in rivers, lakes, seas, and ponds. seaweed are often green, although they can also be found in other hues. For instance, the carotenoid pigments and chlorophyll present in the seaweed that live in snow give the surrounding snow its unique red color.
The term "algae" refers to a class of mostly watery, photosynthetic, and nucleus-bearing organisms that lack the real roots, stalks, and leaves of plants as well as their specialized multicellular reproductive systems.
What are Algae?
In addition to ponds, brackish waterways, and even snow, seaweed may be found in rivers, lakes, seas, and ponds. seaweed are often green, although they can also be found in other hues. For instance, the carotenoid pigments and chlorophyll present in the seaweed that live in snow give the surrounding snow its unique red color.
The term "algae" refers to a class of mostly watery, photosynthetic, and nucleus-bearing organisms that lack the real roots, stalks, and leaves of plants as well as their specialized multicellular reproductive systems.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
1. PRESENTED BY – SADAAT ALTAF KANTH
Msc. Microbiology ( 1st Semester)
UNIVERSITY OF KASHMIR
2. INTRODUCTION
Cyanobacteria ( cyano = blue) are prokaryotic organisms and placed in
Volume 1 of Bergey’s Manual of Systematic Bacteriology .
They were originally studied by botanists and classified as blue green algae
incorrectly. These organisms due to their prokaryotic structure were
studied separately and called cyanobacteria due to their close relationship
with bacteria ( R. Y Stanier & Cohen-Bazire ).
There are about 150 genera and 1500 species of cyanobacteria
They are considered to be 1st oxygen evolving phototrophs that paved way
for evolution of other life forms on Earth and thus responsible for
conversion of atmosphere of earth from anoxic to oxic ( Great Oxygenation
Event).
Cyanobacteria constitute a large, morphologically, ecologically and
physiologically diverse group of phototrophic bacteria.
They are different from algae because of their prokaryotic structure and
differ from other photosynthetic bacteria because they perform oxygenic
photosynthesis.
4. ECOLOGY ( OCCURANCE)
Cyanobacteria are widely distributed in nature especially tropical countries.
They can be found in terrestrial as well as aquatic habitats including freshwater
and marine water.
One of the most characteristic habitat is tropical paddy fields.
Other conspicuous places where they can be found includes microaerobic/
reducing habitats like mangrove marshes & hypersaline lakes
They are more tolerant to extreme environments than algae and are sole
oxygenic phototrophs in hot springs, saline lakes and other extreme
environments.
They are also found on surface of rocks/soil and occasionally within rocks.
They form extreme crusts over the surface of desert soil and remain dormant
there for years and grow during the brief winter and spring rains
Cyanobacterial mats of considerable thickness form on shallow marine bay.
Blooms are formed in freshwater lakes those rich in nutrients (formed due to
high growth rates , tolerance to dessication and production of allochemicals)
They also form symbiotic association with liverworts, ferns and cycads.
Symbiotic association of species of Anabaena with water fern Azolla is
responsible for nitrogen fixation
5.
6. GENERAL CHARACTERISTICS
They have a prokaryotic cell organization ( lack membrane bound
organelles, and a typical double membraned nucleus)
Size varies considerably between taxa. Cell size ranges from 0.5- 1
micrometre for unicellular cyanobacteria to as large as 40 micrometres in
filamentous cyanobacteria, Oscillatoria princeps.
Cyanobacterial cells can be spherical, ellipsoid, barrel shaped, cylindrical ,
conical or disc shaped.
Cyanobacteria have 5 morphological forms
1. Unicellular forms , usually dividing by binary fission like Gleotheca ,
which is around 5-6 micrometres in diameter.
7. 2.Unicellular, Colonial form dividing by multiple fission (Dermocarpa)
3. Filamentous conatining heterocysts that function in Nitrogen
fixation.(Anabaena -5 micrometres in diameter)
4.Filamentous , non heterocystous forms (Oscillatoria- 15 micrometres)
5. Filamentous,branching forms like Fischerella
8. The cell wall is similar to that of gram negative bacteria . Peptidoglycan ,
LPS and proteins are present in the cell wall.
They produce mucilagenous envelopes and sheaths that binds group of
cells in colonial forms. Mucilage is secreted in directional manner and
helps in sticking to solid surface
They do not posses flagella. Filamentous forms of cyanobacteria show
gliding motility when they are in contact with solid surface . They also show
directional movements like phototaxis and chemotaxis.
Peripheral region of cell is transversed by large number of lamellae or
thylakoids. Thylakoids act as the site for photosynthesis and respiration.
The adjacent thylakoids are seperated from each other by a space which is
occupied by phycobilisomes.
Phycobilisomes consists of Phycobiliprotien pigment and allophycocyanin
surrounded by other pigments in stacklike structures.
Photosynthetic pigments present in cyanobacteria are chlorphyll a, and
characteristic biliprotien pigments called phycobilins. Phycocyanin (blue) ,
phycoerythrin (red).
9.
10. The color of the water blooms formed by cyanobacteria depends on ratio
of these pigments to each other.
Chromatic adaptation – The phenomena where pigmentation is
determined by quality of light or capacity to change color complementary
to light. Cyanobacteria use different strategies for doing so like sensory
rhodopsins, phytochromes and membrane associated receptors that sense
UV and blue light.
There are various subcellular organelles observed in cynobacterial cells
1. RIBOSOMES (70 S) which are involved in protien synthesis.
2. POLYPHOSPHATE BODIES which are sites of phosphorus storage
3. CARBOXYSOMES also called polyhedral bodies which contain enzyme
Ribulose- 1,5 bisphosphate carboxylase that is responsible for C02
fixation
4. GAS VACOULES / AEROTPOES measuring about 15 micrometre in
diameter and 1 micrometre in length. This structure regulates cell
buoyancy such that cells can retain a position in water column
11. 5. CYANOPHYCIN is a Copolymer of arginine and aspartic acid and a nitrogen
storage product. Constitutes 10% of cell mass.
It is also an energy reserve in cyanobacteria
Aginine + ADP+ Pi +H20 Ornithine+ 2NH3+ CO2+ATP
(Arg dihydrolase)
6. HETEROCYSTS are specialized, enlarged and rounded cells distributed
regularly along filament or located at one end of filamnent.
They arise from differentiation of vegatative cells.
Allow fixation of atmospheric Nitrogen ( diazotrophy)
They have intercellular connections with adjacent vegetative cells.
Surrounded by thickened cell wall containing large amounts of glycolopids.
12. NUTRITION
They require nitrate or ammonia as nitrogen source
They are mostly obligate phototrophs that are unable to grow in dark
Few grow in dark on glucose using sugar as both cabon and energy source
Media used for growing them is BG 11 medium ( liquid broth) optimized
for their growth and maintainence
REPRODUCTION
Asexual reproudction is seen in cyanobacteria
1. Binary fission where parent cell divides into 2 daughter cells.
2. Baeocytes , small spherical cells arise from multiple fission and are
released after rupture of fibrous outer wall layer of parental cell.
3. Fragemtation – in filamentous cyanobacteria filaments fragment to small
pieces called hormogonia.
4. Spore formation – endospores as well as exospores can be formed
5. Akinites – thick walled specialized cells meant for perennation and
protect organism during unfavourable conditions.
16. ECONOMIC IMPORTANCE
Cyanobacteria have a wide number of industrial,biotechnological,medical and
agricultural applications.
They are one of the earliest colonizers of extreme environments and provide
conditions for growth of organisms even in most hostile environment.
They fulfill vital ecological functions being global contributors of carbon and
nitrogen
Function as food for aquatic animals.
Spirulina also called single cell protein,high in proteins is used as supplement
for humans and animals.
In Rajasthan Anabaena and Spirulina are collected from Sambar lake and used
as fodder and manure.
They can be used as natural food coloring agents.
Several cyanobacteria have ability of nitrogen fixation. Some of the fixed
nitrogen comes out as excretion and the substratum becomes rich in N. Such
cyanobacteria are inoculated in rice fields, thus saving consumption of nitrogen
fertilizers.
Nitrogen fixing cyanobacteria are also used for reclaming usar soil like
Anabaena , Nostoc
Efficiently used as biofertilizers and plant growth promoters
17. Improve tolerance of plants to abiotic stresses and reduce biotic stresses.
Recently used in heavy metal bioremediation.
Antibiotics can be manufactured from extract of Lyngbia.
Fischerella muscicola synthesizes some antibiotic that kills related algae
(fischerellin)
Synechocystic sp was 1st prokaryotic genome whose whole genome
sequence was completely sequenced. It continues to be an model
organism for study.
They can be used to generate renewable energy by directly converting
sunlight into electricity.
Sulfate polysaccharides secreted by them exhibit antitumor,
antimutagenic,antifungal and even antiviral action against HIV , herpes
and hepatitis.
Some secondary metabolites produced by them are algicidal as well.
Cyanovin secretes this secondary metabolite having anti HIV activity
Edible cyanobacteria are also known to reduce risk of cataracts and age
related macular degeneration.
18. Some Cyanobacteria can also show negative effects
They can grow on walls and roofs of buildings during rainy seasons and
cause discoloration and leakage.
Water blooms growing on nutrient rich water bodies can be toxic to the
aquatic fauna and can also make the water unfit for drinking.
Apart from this they cause aesthetic problems by altering the color and
odour of the water bodies.
Water blooms and their accumulation in water bodies can cause poisoning
of aquatic fauna like shellfish
Few cyanobacteria also produce geosmins which have a earthy musty
odour
Cyanobacteria produce toxins which are called as cyanotoxins which can be
of 3 types
1. Hepatotoxins
2. Neurotoxins
3. Endotoxins (LPS)
19. Acute illness can be caused by consumption of drinking water
contaminated by these cyanotoxins.
BMAA ( beta-methylamino-L-alanine) is a type of neurotoxin and has a
potential role in various neurodegenerative disorders like Parkinson’s
disease, Dementia and Amyotrophic lateral sclerosis.
Several species of Anabaena and Aulosira are used to prevent growth of
mosquito larva.
The oldest known fossils are also of Cyanobacteria
In addition to photosynthetic pigments , they produce pigments that
protect cells from intense irradiation (UV rays) eg the Scytonemin ,a black
pigment produced by Scytonema species.
