Page 88 - BBC Focus - August 2017

WHAT CONNECTS…

…FROGS AND FRESH MILK?

1.

Frogs, like
all a amphibians,
have t thin, porous
sk kin that they
can breathe
through. But this
also poses a risk
because it makes it
easier for bacteria to
Do seagulls drink seawater? And if so, how do they infect them.
deal with the salt?
SIMON HARVEY, VIA TWITTER
2.
All seabirds drink seawater – yet birds These look like miniature kidneys and
have less efficient kidneys than work in a similar way, pumping salt To protect
mammals, and so excess salt is even ions out of the bloodstream against the themselves,
more toxic to them than to us. Seabirds normal flow of osmosis. The extra- frogs secreete
substancess
cope with this by using specialised salty water drips down the side of called
salt glands next to their eye sockets. their beak. LV cationic
antimicrobial bial
peptides (CAMPs). Other
animals secrete CAMPs too, but
What is the biggest a moon frogs produce much more,
including some peptides that
are effective against multi-
can be in relation to its resistant bacteria.

mother planet?
3.
EDWARD SEYMOUR, HOVE

Milk goes off
M M M M M M M M M M M M M M M M M M M M M M M
A ‘moon’ is an astronomical body But the distinction between ‘double’ because of
that orbits a planet; the definition and ‘parent-moon’ systems is not bacteria,
doesn’t involve size. So, a ‘moon’ officially defined. Some astronomers especially
could be a small rock or it could be define a ‘parent-moon’ system as one species of
as large as its ‘parent’. However, that has the point about which both Lactobacilli and
similar-sized objects orbiting each objects orbit (the barycenter) inside Pseudomonas. These
other are normally called ‘double’ the larger object, but this distinction ferment the lactose in
(for example, Pluto-Charon is often is quite arbitrary because it depends milk into lactic acid, and
considered a ‘double dwarf planet’). on both size and separation. AGu hydrolyse milk proteins
into various unpleasant
tasting by-products.
4.

According to Russian folklore, putting PHOTOS: GETTY X4, SCIENCE PHOTO LIBRARY, SHUITTERSTOCK ILLUSTRATIONS: RAJA LOCKEY
a live frog in milk would help it stay
fresh. Recent research
has found that
CAMPs from the
Russian brown
frog could kill
the bacteria in
milk and
prevent it
from turning.

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