Introduction to Bacteria ..

introduction to Bacteria,structure, classification on basis of shapes,cell wall, nutrition,reproduction and bacterial infection.

1. Bacteria

2. Introduction ALI ZAHID OD02181008

3. Bacteriology Bacteriology is the branch and specialty of biology that studies the morphology, ecology, genetics and biochemistry of bacteria as well as many other aspects related to them.

4. Bacteria A prokaryotic and single cell microorganism. Small in size. Don’t have nuclear membranes and also lack membrane bound organelles. Can be able to see by using Microscope.

5. Bacteria are found in every habitat on earth, like growing in soil, acidic hot springs and deep earth crust. Bacterial cells are 10 times smaller than the eukaryotic cells and are typically 0.5 to 5.0 micrometers in length. There are 40 million bacterial cells in one gram of soil and million in one milliliter of water.

6. History In 1683 “A nton van Leeuwenhoek” d escribes microscopic “ STREAKS a nd THREADS ” among his tiny a nimals. The Streaks and Thread r emained nameless until 1773.

7. In 1773 Danish scientist named Otto Frederick Muller named them as “ Bacilli ”. But not Bacilli were rod some were spiral and some were in Circular shapes.

8. In 1850 the French Investigator Casimir Davaine began calling this m icroscopic Creatures as Bacteria . This derivatives also mean rods .

9. Structure of Bacteria Capsule: Protective covering. Made of polysaccharides. Protect it from phagocytosis by larger Micro-organisms. Cell Envelope: The cell envelope is made up of two to three layers: the interior cytoplasmic membrane, the cell wall, and in some species of bacteria an outer capsule.

10. Cell Wall: Composed of polysaccharides. Gives the cell its shape and surrounds the cytoplasmic membrane. Protection Cytoplasm: Helps in the cell growth, metabolism, and also in replication.

11. Cytoplasmic Membrane: Layer of phospholipids and proteins . Regulate the flow of materials in and out of the cells. Flagella: Hair-like structure. Provide means of locomotion. The flagella beat in a propeller-like motion to help the bacterium move toward nutrients; away from toxic chemicals.

12. Nucleoid: Region where the chromosomal DNA is located. It is not a membrane bound nucleus. Most bacteria have a single, circular chromosome that is responsible for replication, although a few species do have two or more . Pili: Many species of bacteria have pili (singular, pilus ) small hair like projections emerging from the outside cell surface. These outgrowths assist the bacteria in attaching to other cells and surfaces, such as teeth, intestines.

13. Classification of Bacteria Bacteria can be classified on the following basis: Basis of shapes Cell wall Flagella Nutrition Temperature response

14. On the basis of SHAPES QAYOUM HUSNAIN OD 02181059

15. Classification Bacteria are classified into 4 types on the basis of shapes: Coccus Bacillus Vibrio Spirilla

16. Coccus A coccus ( cooci ) is any bacterium or archaeon that has a spherical,ovoid,or generally round shape. Arrangements: Diplococci are pairs of cocci . (e.g. streptococcus pneumoniae )

17. Staphylococci are irregular (grape-like) clusters of cocci(e.g. Staphylococcus aureus ) Tetrads are clusters of four cocci arranged within the same plain(e.g. Micrococcus sp .) Sarcina is a genus of bacteria that are found in cuboidal arrangements of Eight cocci . ( e.g. Sarcina ventriculi . ) Streptococci are chains of cocci (e.g. streptococcus pyogenes )

18. Bacillus: Bacillus is a genus of Gram positive rod shaped bacteria. Bacillus species can be either Obligate aerobe or Facultative anerobe bacilli. OBLIGATE AREOBE: Depend on Oxygen. FACULTATIVE ANEROBE: Have ability to grow in the absence of Oxygen.

19. Vibrio Vibrio is a genus of Gram negative bacteria possessing a curved rod shaped comma shape . Vibrio are found in salt water . All members are motile and have flagella .

20. Spirilla Spiral bacteria are the helical shape bacteria They have two types Spirrilum (e.g . Campylobacter jejuni ) Spirochete (e.g . Treponema pallidum )

21. On the basis of Cell Wall RABIA SAIFULLAH OD02181030

22. GRAM POSITIVE Gram positive and negative are classified on the abililty to retain the gram stain. The gram positive bacteria would retain the gram stain and observe as violet colour after the application of iodine and alcohol. Cell wall consist of many layers of PEPTIDOGLYCANS which forms a thick and rigid structure.It also contain “Techoic Acid” which is made up of alcohola and phosphate. Two types of techoic acis are formed: Lipotechoic Acid: Which spam the peptidoglycan layer linked to plasma membrane. Techoic Wall Acid:Which is connected to peptidoglycan layer.

23. GRAM NEGATIVE The gram negative bacteria would be stained by the counter stain safranin, as they are destined due to alcohol wash so they appear as pink coloue under microscope. Cell wall is made up of few layers of peptidoglycans and an outer membrane. The outer layer is made up of Lipopolyssacchrides, Lipoproteins and Phospholipids. The peptidoglycans remain bound to the lipoproteins of the membrane.It is present in periplasm, which is jel like fluid between the outer and plasma membrane.

24. Due to presence of lipoproteins in the outer membrane, cell is not easily affected by antibodies, enzymes and metals. The outer membrane is permeable due to presence of “ PORIONS ’ and is permeable to food, nutrition, water, vitamin B12 and Iron.

25. On the basis of Nutrition

26. Autotrophic Bacteria Food is syntesised from simple inorganic raw material CO2 and H2O . Green pigment is necessary . Food is prepared during daytime. EX: All GREEN plants and some bacteria Hetrotrophic Bacteria Food is obtained directly or indirectly from autotrophs. No pigment is necessary for nutrition. Food can be prepared at all the time. Ex: All animals and Fungi.

27. On the basis of Flagella Bacteria are classified on the basis of flagella: A- trichous Mono-trichous Amphitrichous Lophotrichus Peritrichous Cephalotrichous

28. Reproduction Of Bacteria ASAD HUSNAIN OD 02181055

29. Method of reproduction Sexual reproduction Asexual reproduction Asexual reproduction In asexual reproduction single organism produce genetically identical offspring . Types: Endospore formation Vegetative reproduction

30. Endospore formation Resting spores found in gram positive bacteria . During formation protoplasm constricted around the chromosomes and a hard resistant wall secreted around it. Rest of the bacterial cell degenerate.

31. Vegetative reproduction

32. B udding Small protuberance bud, develops at one end of bacteria. Genome replication occurs, and one copy of genome gets into the bud. Bud enlarges and eventually separate from the parent cell.

33. F ragmentation During unfavorable condition, bacterial protoplasm undergoes compartmentization forming minute bodies called Gonidia . During favorable condition each Gonidia Grows to new bacterium.

34. Sexual reproduction In sexual reproduction, two parents are involved and offspring are not genetically identical. Types : Conjugation Transformation Transduction

35. C onjugation In conjugation one bacterial cell transfer genetic material into other bacterial cell. Its is transferred in form of plasmid known as “ F-plasmid .” A cell that has a copy of F-plasmid is known as F positive and this cell is donor. The cell that does not have copy of F-plasmid is known as F-negative and it is recipient cell.

36. Steps of conjugation F- positive cell produce pilus. The pilus enables the direct contact between the donor and the recipient cells. An enzyme relaxasome transferasome nick one of the two DNA stands of F-plasmid and this strand is transferred to recipient cell. Both donor and recipient cell to contain single stranded DNA . Replication of this DNA occur forming double stranded F-plasmid identical two original F-plasmid.

37. T ransformation In transformation a bacteria takes in DNA from its environment often DNA that has been shed by another bacteria. If DNA is a circular DNA called a plasmid, It can be copied in receiving cell.

38. Transduction In transduction viruses that infect the bacteria ( BACTERIOPHAGE ) move short pieces of chromosomal DNA from one bacterium to an other by accident.

39. Bacterial Infection MARIA SAEED OD02181098

40. Baterial infection It an invasion of body tissues by disease causing Bacteria or the poliferation of harmful stains of bacteria that can effect any part of body. It can be caused by contact with : I nfected people. Coughing and sneezing. With infected creatures. With contaminated surfaces.

41. Carbuncle Carbuncle is the skin infection resulting in th formation of LUMP that may contain pus . It is also known as “ STAPH SKIN INFECTION ”. Caused by group of contegious follicles with “ Staphylococcus Aureus ”. CLINICAL FETURES: Fever Fatigue Irritation Pain around infected area Itching

42. Tularemia It is also called “ RABBIT FEVER ”.  It is caused by the bacterium   Francisella tularensis that can effect your SKIN, LUNGS, EYES and LYMPH NODES. CLINICAL FEATURES: Uleroglandular (most common) Oculoglandular Orophyrangeal

43. Impetigo It is caused by Staphlococcus aureus and A. Streptococcus . M ostly occur in infants and children . Lead to complications like cellulitus ,kidney problems and scarring. CLINICAL FEATURES: Ictching Swollen lymph nodes Open sores with yellow crust Painful blisters

44. Bollus : “ Staphalococcus Aureus ” Vesicles rupture easily. Honey coloured crusted plague. Non- Bollus : “ S.Aureus, A.streptococcus ”. Less rupture and become large. Persist 2-3 days.

45. Leprosy An infectious disease also known as “ Henson’s Disease ”, caused by MYCOBACTERIUM LEPRAE . CLINICAL FEATURES: Damages to SKIN and PERIPHERIAL NERVES . May involve other organs like Testes , bones and muscles, eyes, upper respiratory tract .

46. Cancrum oris Also known as “ GANGREONUS STOMATITIS ” (NOMA). Caused by oral contamination of by heavy infestation of “ FUSOBACTERIUM NECROPHORUM ”. CLINICAL FEATURES : Suffer from dibalitating diseases. Spread rapidly and become necrotic. Gingival Ulcer

47. Gonorrhoea An infection caused by sexually trasnmitted bacteria that often affects the urethra, rectum or throat . It is caused by “ Neisseria gonorrhoeae ”. CLINICAL FEATURES: Painful urination. Swelling in testicles . COMPLICATIONS: Infertility in males and females. High risk of HIV. Complications in babies.