6 Aug 2011

Classification associated with Plasmids in Bacterial


Classification associated with Plasmids - Based upon the number of duplicates for each cellular, plasmids tend to be categorized into two sorts.
1. Stringent plasmids
These plasmids exist in small numbers, i.e. <100 duplicates/cellular. Stringent plasmid is under the particular control associated with bacterial genome for replication and segregation. Generally, conjunctive plasmids tend to be mostly stringent plasmids.
2. Relaxed plasmids
These plasmids exist in bigamounts, i.e., > 100 duplicates/cellular. Relaxed plasmid is actuallynot under the actual control associated with bacterial genome for replication and segregation. Generally, relaxed plasmids tend to be of low molecular weight and most associated with them are usually associated with the non conjugative type.
The most widely used method to find the particular copy number regarding the plasmid is to estimate the amount of enzyme encoded by genes present in the plasmid. For example, J3-lactamase activity can be measured if the actual plasmid specifies ampicillin resistance.
Sometimes plasmids are usually also labeled into compatible groups, based after plasmid incompatibility. Plasmid incompatibility is the particular inability associated with two different plasmids to co exist in the same cell in the particular absence regarding selection pressure. But this method is not widely used.


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