Read the passage below. Use the information in the passage and your own knowledge
to answer the questions that follow.
Alligators save lives
Many humans are frightened of being attacked and eaten by alligators.
However, alligators may have a role as potential lifesavers. Scientists have
discovered proteins in alligator blood called alligacins. They hope these
proteins may provide a source of new antibiotics to help fight infections,
5 particularly those associated with diabetic ulcers and severe skin burns.
The scientists collected blood samples from alligators. They extracted
the antibiotic proteins from the white blood cells involved in destroying
pathogens. In laboratory tests the protein extracts killed a wide range
of bacteria, including MRSA (methicillin-resistant Staphylococcus aureus).
10 These ‘superbugs’ are increasingly resistant to many antibiotics and cause
thousands of deaths each year.
The investigation by the scientists of the antibiotic properties of alligacins
discovered a range of other uses for these proteins. For example, they help
to cure infection caused by the yeast Candida albicans in AIDS patients. The
15 antibiotic proteins killed six out of eight different strains of Candida albicans.
They also discovered that the blood proteins may help destroy HIV, the virus
that causes AIDS.
Alligators have an immune system that is different from the immune system
of humans. Humans need a vaccination to be able to respond quickly to
20 infection by pathogens. However, the alligator immune system can quickly
destroy pathogens without having had prior exposure to them. Scientists
believe that natural selection has created this evolutionary adaptation as
it promotes quick wound healing. These wounds are caused by alligators
fighting to defend their territory from other alligators.
25 The scientists are hoping to identify the exact chemical structures of
the antibiotic proteins. They can then begin to develop antibacterial or
antifungal drugs.
What is meant by the term pathogens (line 8)?
(1)
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