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Bacteria were discovered by Leeuwenhoek.

Pleuro Pneumonia Like Organism.

Bacteria not stained by crystal violet.

Bacteria stained by crystal violet.

Mycoplasm is transmitted in plants through leaf hopper insect. They are also transmitted during plantation. It is transmitted from plant to plant by Amarbel(Mistletoe).

1. Mycoplasma is without rigid cell wall. hence cancontort into broad range of shapes. from round to
   obÍong They are called as clones of animal kingdom.
2. They are unicellular, non-motile & smallest prokaryotes. They form colony which is like a fried egg.
3. They inhabit decaying material, excreta, soil, plants & animals.
4. They are parasitic / saprozoic.
5. They have both DNA & RNA but DNA is less than RNA.
6. They can easily ber cultured on non-cellular culturemedium but stero is are essential for their growth
7. Mcopiasma are Gram negative (G-)
8. The are not sensor to any enzyme, as they arc with out  wall  Hence, the remain unaffected by antibiotics
   like penicillin, vanconiycin, cephaloridine etc.

Cell wall & capsule – Every bacterium is bounded by a cell wall which is similar to the exoskeleton of in¬sects, In most of the bacteria, a jelly-like extra layer is found outside the cell wall which is called as slime layer. In some bacteria, it is very thick & called as capsule. The slime layer consists of carbohydrates, amino acids & gum.

Classification of Fungi:
Many classification have been propounded by different scientists from time to time.In this chapter, the classification given by Alexopoulus is followed. C.J. Alexopoulas (1962 and 1968) placed all the fungi under division-Mycota. The salient features of mycota are minute thallus, unicellular or filamentous, nucleus with distinct nuclear membrane, chitinous cell wall, reproduction both asexual and sexual etc. Division – mycota is divided into 2 subdivision viz – My ⇒ xomycetes & Eumycotina.

(A) Subdivision – Myxomycotina : Plant body is in the form of nacked protoplasm called plasmodium. 1 class ⇒ Myxomycetes – Vegetative phase is Plasmodium. Reproduction takes place by very small multi nucleated spores.

Example – Physarum

(B) Subdivision – Eumycotina : Vegetative phase is either unicellular or branched mycelium with distinct cell wall. Hyphae are coenocytic or septate. Each cell may be uni, bi or multinucleated.

Reproduction by spores (asexual) and gametes (sexual) It has been divided into eight natural classes and one
form-class –

1. Class – Chytridiomycetes.
Motile cells with single whiplash flagellum placed posteriorly.

Example – Synchytrium.

2. Class – Hypochytridiomycetes.
It includes aquatic fungi. Motile cells with single tinsel flagellum placed anteriorly.

Example – Rhizidiomyces.

3. Class – Oomycetes.
It includes parasitic & saprophytic fungi. Vegetative phase consists of multinucleated and well developed mycelium. Motile cell have two flagella ie. biflagelate consists of one Whiplash & the other Tinsel type.

Example – Albugo.

4. Class – Plasmodiophoromycetes.
It includes parasitic fungi. Multinucleate thallus without cell wall. Motile cells are with two whiplasm flagella of unequal length.

Example – Plasmodiophora.

5. Class – Zygomycetes.
Well developed coenocytic mycelium grows either parasitically or saprophytically. Motile cells are absent.

Example – Mucor.

6. Class – Trichomycetes.
Multinucleated simple or branched thallus. Mostly parasitic on Arthopods.

Example – Harpella.

7. Class – Ascomycetes.
Well developed mycelium with septate hyphae. Ascospores are produced endogenously inside ascus.

Example – Neurospora.

8. Class – Basidiomycetes.
Well developed mycelium with septate hyphae. Basidiospores are produced exogenously on basidium.

Example – Puccinia, Agericus.

Form – class – Deuteromycetes: Well developed mycelium with septate hyphae sexual phase unknown. Reproduces mainly by asexual means.

Example – Alternaria.

Bacteria are cosmopolitan, they are found in land, soil, air water, food, animals, plants etc. Many types of bacteria are found in human intenstine such as Eschrichia coli. They are found in temperature from -190°C to 78°C and some can survive in Ice and boiling water.
They are found in air up to height of many thousand feet and in thc Earth upto adepth of 16 feet, Bacteria are not found in rain water, distilled water, deep well water and volcano ash. They are abundantl found in faeces, milk products. fruits, vegetables etc.

Importance of Fungi increased with the developement of human culture.

(A) Beneficial Fungi:

(i) Fungi as Food – They are rich sources of proteins, carbohydrates & salts, hence many of them are used as food. Such as Morchella esculenta, Agericus bispora. Agericus campestris etc. Yeast is a supplementary food for human beings & cattles.

(ii) Industrial use – Many fungi are used to obtain enzymes, carbonic acid and alcohol. For example Citromyces pfefferianus, Penicillium oxalicum and Asperigillus oryzae are used to get citric acid, oxalic acid & lactic acid respectively. Similarly, alcohol is obtained by fermentation of sugar performed by Saccharomyces cerevisiae. Vitamin D and vitamin B complex are obtained by the action of Penicillium, Aspergillus and Yeast.

(iii) Medicinal uses – Many fungi are used to obtain antibiotics, such as penicillin is obtain from Penicillium notatum, anti amoebin from Emericellopsis punensis and SQ30, 957 from Penicillium funiculosium. Alkaloids used in various diseases such as argotamin, Argotoxin etc are obtained from fungus Claviceps purpurea. The steroids obtained from Mucor griseo- cyanus & Rhizopus stolonifer are used to treat arthritis, allergy etc.

(iv) Plant hormones – Popular gibberellin growth hormone is obtained from Gibberella Jujikuroi and Fusarium Moniliforme fungi.

(B) Harmful Fungi:

Many species of fungi are harmful and caure diseases in man and plants.

1. Plant diseases – Plant diseases caused by fungi are very common. Such is White Rust disease of mustard is caused by Albugo Candida; Green ear disease of millet caused by Sclerospora graminicola; Rust diseases of wheat by various species of Puccinia; Tikka disease of groundnut caused by Cercospora per sonata etc.

2. Fungal diseases of man & cattles – The fungal diseases caused in man & cattle are called as mycosis. Such as Aspergillus funigatus infects lungs; Trichophyton causes ring worm disease etc.Candiasis is infection of skin, mouth, respiratory tract is caused by Candida albicans.

3. Spoilage of food products – Many fungi such as Mucor, Neurospora spoil food products like milk, curd, cheese, meat, fish, bread, fruits, vegetables, pulses etc.

4. Some fungi are highly poisnous and their intake is lethal. Some poisnous mushrooms are Amanita, Russula, Boletus etc.

Lichens are composite organism (symbionts) of algae & fungi. Their alga & fungus components are respectively called as Phycobiont and Mycobiont. The phycobionts belong to cyanophyceae & chlorophyceae and mycobionts belong to Ascomycetes and Basidiomycetes. Lichens in India are found in Himalaya regions, moist shady regions, on the bark of trees and on the rocks with bryophyte plants.The vegetative part of Lichen is thallus.

The thallus is flat, leaf like and lobed. It resembles the dried liverworts of bryophate. The thallus has distinct dorsal and ventral surfaces. The dorsal surface is dark brown or light green whereas the ventral side is black in colour. The thallus is attached to the substratum! with the help of ventral rootlets called rhizines. The rhizines are single, branched or unbranched hyphae.The internal structure of the thallus is complex.

Internally, it has apper cortex, algae layer, medulla and lower cortex.Nutrition to lichen is provided by alga. The alga synthesize sugar by photosynthesis. This sugar is used by fungus. Hence, there is symbiotic nutrition. Vegetative reproduction in lichen takes place by fission & special structures called soredia & insidia.Sexual reproduction in lichen depends on fungus. If the associated fungus is member of Ascomycetes, the sexual reproduction is by ascospores.

The ascospores are formed in asci (singular – ascus) which are confined in funnel body called Apothecium Male reproductive organs are called sporogonium and female reproductive organs are called as carpogonium.

Types of Lichens:

They are of three types on the basis of shape & structure viz.

1.Crustose Linchens – Their thallus is flat and they grow lightly appressed to a substrate forming a biological layer of the adhering organism. They adhere very closely to the substratum at all points with the help of rhizines. The shape of the thallus may be round or oval or branched. The colour of the thallus is brown or red or yellow or black etc.

2.Foliose Lichens – These lichens are flat & lobed like leaf. The thallus is attached to the substratum with the help of rhizines which may be branched or unbranched. Some leafy lichens are attached with the help of hapteron. In some lichens, the rhizines have disc- like ends which secrete mucilase that help in attachement.
Example – Gyrophare, Parmelia, Collema etc

3.Fructose Lichens –  The Thallus of these lichens is highly branched & they are bush-like. They are Cylendrical or ribbon-like and branched.

The branches are hairy or leafy. Upper & lower surface are not distinct in the Thallus. The Thallus is attached to the substratum with the help of Flate disc. The Thallus is brownish green, yellowish green, Bluish-green or black.

Example – Usnea, Cladonia etc.

A. Useful Lichens:

•  Lichens develop as pioneer vegetation & begin the process of succession.
• Lichens are highly sensitive to pollution & have zero tolerance to SO₂ pollution. Hence, they are indicator of pollution.
• Some Liches are used as food for insects & catterpilar larvae.
• Liches are also used for treatment of various diseases. Such as Peltigera canina Lichen is used to treat hydrophobia. Parmelia saxatilis is also called as skull lichen and it is used to treat epilepsy.
• Thallus of lichen release special aroma (fragrance), hence is used in dhup batti (incense) & havan (Ritual).
• Some dried lichens are also used as spice.
• Lichen rock is popular as “Pathar ke bhool”.

B. Harmful Lichens:

• During summer the dried lichens become inflammable.
• They catch fire & result in forest fire.
• Some lichens are highly toxic & may be lethal.
• In humid & moist places, the lichens grow on the doors, windows, walls, floor etc & damage the building.

Cell wall of fungi are made up of Chitin.

Alexopoulas.

Little leaf of brinjal disease is caused by mycoplasma.

Com stunt disease & Cotton stenosus disease.

Essential for growth of mycoplasma is Sterol.

Robert Koch.

Rhizobium bacteria inhabit in root nodules of leguminous.