Introduction to Bacteriology

 Bacteria are living forms that are micro-scopical in size (1-10 µm) and relatively simple, unicellular, in structure.

1.Agriculture Bacteriology 2.Food Bacteriology 3.Industrial Bacteriology 4.Medical Bacteriology. General Bacteriology

Eukaryote vs. Prokaryote

Like a warm, dark, and moist environment They are found almost everywhere: –Water, air, soil, food –Skin –inside the body –On most objects Prokaryote Mostly single-celled Circular single chromosome Cell walls It reproduces by binary fission, not by mitotic division. General Characteristic:

Reproduce mostly asexually Anaerobic or aerobic : depending on the species, bacteria can be aerobic which means they require oxygen to live or anaerobic which means oxygen is deadly to them. Bacteria can be autotrophs or heterotrophs

Depend on the Gram staining (or Gram's method) which is an practical method of differentiating bacterial species based on the chemical and physical properties of their cell walls Bacteria can be classified into two types: Gram Positive Bacteria and Gram Negative Bacteria

The Gram stain, which divides most clinically significant bacteria into two main groups, is the first step in bacterial identification. Bacteria stained purple are Gram + (positive) their cell walls have thick petidoglycan and teichoic acid. Bacteria stained pink are Gram – (Negative) their cell walls have thin peptidoglycan and lipopolysaccharides with no teichoic acid.

Bacterial Structures:

A.Essential structures, present in all bacteria B.Structures present in some species (primary taxonomic characters) C.Structures present in some strains of some species The bacterial structures may be divided into three categories:

B. Structures present in some species : 1.Flagella 2.Spores 3.Inclusion granules. A.Essential structures, present in all bacteria 1.Protoplast (cytoplasm and nuclear body) 2.Cytoplasmic membrane 3.Cell wall

1.Fimbriae 2.Sex pili 3.Glicocalix (capsule, microcapsule, loose slime). Structures present in some strains of some species:

Bacteria have different shapes. 1.Coccus: The cocci are spherical or oval bacteria e.g. staphylococcus, diplococcus; two cells together 2.Rod-shaped bacterium or Bacillus, e.g Escherichia coli. 3.The spiral: Spirals come in one of three forms, a vibrio, a spirillum, or a spirochete. Shapes of Bacteria

Nucleoid  A ring made up of DNA  No real complete nucleus Cytoplasm  Clear jelly-like material that makes up most of the cell Capsule  keeps the cell from drying out and helps it stick to food or other cells Major Structures of a Bacteria Cell

 Cell wall Thick outer covering that maintains the overall shape of the bacterial cell  Ribosomes Ribosomes give the cytoplasm of bacteria a granular appearance and it is where proteins are made  Flagella A whip-like tail that some bacteria have for movement  Pilli Heavy hair-like structures made of protein Allows bacteria to attach to other cells.

1.Archaebacteria: extremists 2.Eubacteria: a)Heterotrophs b)Photosynthetic autotrophs c)Chemosynthetic autotrophs Classification of Bacteria

1.Archaebacteria Live in extreme locations: –Oxygen-free environments –Concentrated salt-water –Hot, acidic water

Found everywhere Parasites: depend on other organisms Saprobes: depend on dead organisms or waste (recyclers) Eubacteria - Heterotrophs

a.Eubacteria: Photosynthetic Autotrophs 1.Photosynthetic: make their own food from light 2.Cyanobacteria: blue-green, yellow, or red 3.Ponds, streams, moist areas a.Eubacteria: Chemosynthetic Autotrophs 1.Get energy by breaking down inorganic substances like sulfur and nitrogen 2.Make nitrogen in the air usable for plants

Bacteria are multiply by a simple cell division known as binary fission (splitting into two). The single piece of DNA reproduces itself exactly. When bacterial species produce several forms each with its own characteristics, these variants are called strains. Growth depends on temperature, pH, osmotic pressure, oxygen, and nutrients Reproduction of Bacteria

In the Binary Fission- the process of one organism dividing into two organisms Fission is a type of asexual reproduction It is Asexual reproduction- reproduction of a living thing from only one parent The one main (circular) chromosome makes a copy of itself

Then it divides into two The time of reproduction depends on how desirable the conditions are Bacteria can rapidly reproduce themselves in warm, dark, and moist conditions Some can reproduce every 20 minutes, one bacteria could be an ancestor to one million bacteria in six hours)

Endospore- A thick celled structure that forms inside the cell They are the major cause of food poisoning Allows the bacteria to survive for many years They are highly resistant structures, which can withstand boiling, freezing, and extremely dry conditions It encloses all the nuclear materials and some cytoplasm Bacteria survival

1.parasites – bacteria that feed on living things 2.saprophytes – use dead materials for food (exclusively) 3.decomposers : get food from breaking down dead matter into simple chemicals important- because they send minerals and other materials back into the soil so other organisms can use them Bacteria Survival – Food sources

Harmful Bacteria some bacteria cause diseases Animals can pass diseases to humans

Disease passed from one organism to another This can happen in several ways: Air Touching clothing, food, or toothbrush Drinking water that contains bacteria Communicable Disease –

Paired: diplo Grape-like clusters: staphylo Chains: strepto Bacterial Arrangement