Gram-negative bacteria protect themselves with an outermost layer containing lipopolysaccharide (LPS). O-antigen-specific bacteriophages use tailspike proteins (TSP) to recognize and cleave the O-polysaccharide part of LPS. However. O-antigen composition and structure can be highly variable depending on the environmental conditions. https://www.markbroyard.com/best-offer-dogijiwana-tuffer-chewer-pretzel-online-flash-choice/