Lysosomes and Microbodies

Done By :Zeophuen Sahoo

CELL

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Lysosomes

History of Lysosomes

The history of most cell organelles has been early description by microscopists followed many years later by isolation and biochemical characterization. Some found it in the mitochondrial fraction (Palade, 1951; Schneider and Hogeboom, 1952), while others, using somewhat lower centrifugal force, found it in their microsome fraction (Novikoff et al., 1953). This problem was resolved by DeDuve and his associates, who were able to separate the classical mitochondrial fraction into two subfractions.

•Membranous sacs filled with enzymes.

• Found - eukaryotic cells•Act as 'garbage disposal' of the cell

•Size ranges between 0.1 to 1.2μm.•Varing in size from organism to organism.

•Manufactured by the Golgi apparatus, by budding, in the cell and the various digestive enzymes, that are present in the lysosomes reproduced in the endoplasmic reticulum.

Structure of Lysosomes

Electron Microscopic pictures of lysosomes.

www.biology.unm.edu

•A lysosome is a small spherical organelle found near the golgi apparatus in a cell.

• It is found in both plant and animal cells, but is more common in animal cells.

•An easy way to remember it is to imagine a ‘can of Lysol’.

•Lysosomes are not visible under a light microscope.

Location of Lysosomes

Another example of lysosomes clustered in the Golgi region. On these the limiting membrane, which is one of their defining characteristics, is clearly visible. It is often very closely applied to contents of similar density and is therefore difficult to resolve.(The Cell Book)

Types of Lysosomes

Peroxisome

•Vesicle containing oxidases and catalase.•Smooth ER of the animal cell•Oxidizing amino acids and fatty acids; also detoxifing alcohol.

Proteosomes

•Tiny barrel-shaped structure that contain proteases.• Degrading unneeded, damaged, or faulty proteins by cutting them into small peptides.

•disposal system of the cell.

•To breakdown complex into simpler compounds(proteins, carbohydrates, lipids ).

•phagocytosis process.

•Another interesting function repair the damages to the plasma membrane. They serve as membrane patch and help in sealing the wound in the plasma membrane.

Functions of Lysosomes

Lysosomes are also involved in programmed cell death, or autolysis, which is a catabolic process involving degradation of the cell's own components.

This is the reason why lysosomes are often known as 'suicide sacs'.

Functions of Lysosomes (cont.)

•A membrane-bounded cytoplasmic organelle that contains oxidative enzymes.• Microbodies possess a single membrane, are frequently spherical, and typically measure from 20 to 60 nanometers in diameter.•They occur in many types of eukaryotic cells, including those of animals, higher plants, and protozoa.

•Microbodies are believed to originate in the endoplasmic reticulum. Two principal types are peroxisomes, found in vertebrates, and glyoxysomes, found in plants and microorganisms.

History of Microbodies

Ultra structure of Microbodies

www.biology.unm.edu

Glyoxysomes are found in germinating seeds of plants as well as in filamentous fungi.

Woronin bodies are special organelles found only in filamentous fungi.

One established function of Woronin bodies is the plugging of the septal pores after hyphal wounding, which restricts the loss of cytoplasm to the sites of injury.

Functions of Microbodies

Microbodies are found in cells of plants, protozoa, and animals. There are many types of microbodies found in eukaryotic cells. In vertebrates, microbodies are especially prevalent in the liver and kidney organs.

Location of Microbodies

Types include peroxisomes, glyoxysomes, glycosomes and Woronin bodies.

Types of Microbodies

References :

•Cell Biology by Pawar•The Cell by Robert Brown•The Cell by Fawcett•http://en.wikipedia.org/wiki/Lysosome•http://www.authorstream.com•http://www.slideshare.net

Questions

1. What are lysosomes? Explain its types.2. SN on lysosomes.3. Give ultra structure of lysosomes.4. Describe in detail peroxisomes and proteosomes.5. What is microbodies? Who discovered it?6. Types of microbodies?7. Ultra structure of microbodies?8. Which organelle is known as the suicidal bag of

the cell?9. How many types of lysosomes occur? List them

out.

10. Lysosomes are formed by the ________. (a) Mitochomdria (b) golgi apparatus (c)ribosomes (d) nucleus11. Malfunctioning of lysosomes can cause _________

disease. (a) arthritis (b) malaria (c) both a and b (d) none of the above12. Malformed peroxisomes caused_______. (a) zellweger’s syndrome (b) jaundice (c)AIDS (d) none of the above13. Peroxisomes metabolizes _______________. (a) hydrogen peroxide (b) hydrogen oxide (c) both a and b (d) none of the above14. Microbodies are of which types?15. What is the size of the lysosomes?16. Which organelle is responsible for programed cell death?

Research article

Lysosome-related organelles

ESTEBAN C. DELL’ANGELICA, CHRIS MULLINS, STEVE CAPLAN and JUAN S. BONIFACINO1

+ Author AffiliationsCell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-5430, USA ↵Correspondence: 1Correspondence: CBMB, NICHD, National Institutes of Health, Bldg. 18T Room 101, 18 Library Dr. MSC 5430, Bethesda, MD 20892-5430. USA. E-mail: juan@helix.nih.govAbstractLysosomes are membrane-bound cytoplasmic organelles involved in intracellular protein degradation. They contain an assortment of soluble acid-dependent hydrolases and a set of highly glycosylated integral membrane proteins.

Most of the properties of lysosomes are shared with a group of cell type-specific compartments referred to as ‘lysosome-related organelles’, which include melanosomes, lytic granules, MHC class II compartments, platelet-dense granules, basophil granules, azurophil granules, and Drosophila pigment granules. In addition to lysosomal proteins, these organelles contain cell type-specific components that are responsible for their specialized functions. Abnormalities in both lysosomes and lysosome-related organelles have been observed in human genetic diseases such as the Chediak-Higashi and Hermansky-Pudlak syndromes, further demonstrating the close relationship between these organelles. Identification of genes mutated in these human diseases, as well as in mouse and Drosophila pigmentation mutants, is beginning to shed light on the molecular machinery involved inthe biogenesis of lysosomes and lysosome-related organelles.—Dell’Angelica, E. C., Mullins, C., Caplan, S., Bonifacino, J. S. Lysosome-related organelles.

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