Corrected by : Shady Soghayr

Transcription

1 Done by : Renad Abu Rumman Corrected by : Shady Soghayr

2 ممكن تفقد البكتيريا هذه الطبقه عند التعرض لظروف مختبريه S layer is different from slime layer sex pili (common pili) :help in genetic transfer between (donors(male)/recipients(female).

3 The number of flagella is important in the activity of motile. Structure of flagellum : 1- Filament 2- Hook 3- Basal body: * It differ from gram positive or negative. It differs according to the basal body and the number of rings * Gram Positive : 2 rings embedded within the plasma membrane. * Gram Negative : 4 rings " 2 in Cell wall (includes 1 in peptidoglycan and 1 in outer membrane) - 2 in plasma membrane. االبواغ الداخليه Endospore formation ساكنDormant, tough, nonreproductive structure germination vegetative cells.

4 Spore forming genera: Clostridium (very dangerous bacteria). Resistance to UV and radiation, desiccation, lysozyme, temperature, starvation, and chemical disinfectants Relationship to disease Sporulation: Endospore formation Germination: Return to vegetative state N: *More pathogenic than other bacteria why? Because it is resistance to environment conditions (PH, temperature). Additional Q: Is it the spore formation of the bacteria need to reproduction? No, why? Because the spore form from vegetative cell (mother cell) under abnormal conditions (sporulation) and it may be return to vegetative state under perfect conditions (germination) that s mean there is no increasing in the number of cells. ال يمكن للخليه انتاج spores اال اذا كانت تحمل ذلك في جيناتها : Cell can product spore genetically only. Spore can stay 100,000 years so we use it as biological weapon. No water in spore so there's no metabolizing activity (dormant stage). Resting stage during lean or stressful times. Resistant protein coat! Develop in different locations of vegetative cell:

5 Free ; sub-terminal; central; terminal some of the central type form swelling in the cell e.g (c). location of spore is important in the lab for differentiations. عملية صبػ االبواغ صعبه نستخدم الحراره الدخالها واذا صبغت صعب نزيل الصبغه *The position of the spore Is important in the lab and it is used as a diagnostic criteria to differentiate between different clostridium *when we stain the spores we use temperature and other factors and once the spore are stains we cannot exert them from the spores Schaeffer Fulton Stain: Young (24 h) Old (96 h) No spore spore (blue)

6 Forespore االوليه) (االبواغ has two plasma membranes and peptidoglycan form between them. Sporulation : the vegetative cell ( mother ) disappear, spore only exist but before that the DNA replication then a copy of it move to the spore, the spore have a copy of the DNA of the mother cell so it can stay at dormant stage ( save bacteria from extinction). The spore coat Form ( outer ). Depending on the species, the endospore might be located terminally (at one end), sub terminally (near one end, or centrally inside the vegetative cell. When the endospore matures, the vegetative cell wall ruptures (lyses), killing the cell, and the endospore is freed. Most of the water present in the forespore cytoplasm is eliminated by the time sporulation is complete, and endospores do not carry out metabolic reactions.

7 The highly dehydrated endospore core contains only DNA, small amounts of RNA, ribosomes, enzymes, and a few important small molecules. The latter include a large amount of an organic acid called dipicolillic acid which is accompanied by a large number of calcium ions. Because of dipicolillic acid and calcium ions it doesn't pigment unless we increase the temperature Endospores can remain dormant for thousands of years. An endospore returns to its vegetative state by a process called Germination. Sporulation in bacteria is not a means of reproduction. This process does not increase the number of cells. Cytoplasm Composed largely of water, together with proteins, nucleic acid, lipids and small amount of sugars and salts Ribosomes: numerous, 15-20nm in diameter with 70S; distributed throughout the cytoplasm; sensitive to streptomycin and erythromycin site of protein synthesis Plasmids: extra chromosomal genetic elements Inclusions: sources of stored energy, e,g volutin

8 Plasmid Plasmids are small, circular/line, extra chromosomal, double-stranded DNA molecules. They are capable of selfreplication and contain genes that confer some properties, such as antibiotic resistance, virulence factors. Plasmids are not essential for cellular survival. granulose Inclusions are aggregates of various compounds that are normally involved in storing energy reserves or building blocks for the cell. Inclusions accumulate when a cell is grown in the presence of excess nutrients and they are often observed under laboratory conditions. End of the chapter