- published: 12 Sep 2012
- views: 29825
Lysis (Greek λύσις, lýsis from lýein "to separate") refers to the breaking down of a cell, often by viral, enzymic, or osmotic mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a "lysate".
Many species of bacteria are subject to lysis by the enzyme lysozyme, found in animal saliva, egg white, and other secretions. Phage lytic enzymes (lysins) produced during bacteriophage infection are responsible for the ability of these viruses to lyse bacterial cells.Penicillin and related β-lactam antibiotics cause the death of bacteria through enzyme-mediated lysis that occurs after the drug causes the bacterium to form a defective cell wall. If cell wall is completely lost, the bacterium is referred as a protoplast if penicillin was used on gram-positive bacteria, and spheroplast when used on gram-negative bacteria.
Cytolysis is the lysis of cells in a hypotonic environment (the surrounding fluid has a lower salt concentration than the cell interior). Cytolysis is caused by excessive osmosis, or movement of water, toward the inside of a cell (hyperhydration). The cell membrane cannot withstand the osmotic pressure of the water inside, and so it explodes. Osmosis occurs from a region of high water potential to a region of low water potential passing through a semipermeable membrane, so these bursting cells are located in hypotonic environments.
Memories & feelings
Happiness & dreams
You grow these flowers in my heart
(pause)
The letters dance before my eyes
The numbers seem to leave my mind
I walk above the ground, I'm feelin' special now
And even if the sun don't shine above
And even if the rain is fallin'
Down upon my soul
I wanna see you and ask for more
Memories & feelings
Happiness & dreams
You grow these flowers in my heart
I know memories & feelings
Everlasting healin'
I just keep them all inside
(pause)
Been waiting for an angel light
Been walkin' thru the darkest night
But then again I was livin' without you boy
And even if the sun don't shine above
And even if the rain is fallin'
Down upon my soul
I wanna see you and ask for more
Memories & feelings
Happiness & dreams
You grow these flowers in my heart
I know memories & feelings
Everlasting healin'
I just keep them all inside