In an extraordinary biological study, researchers have used chemical analysis to demonstrate that ink preserved in the remains of two cephalopod fossils that date over 160 million years ago to the Jurassic period is almost identical to that used by modern common cuttlefish (Sepia officinalis) today. The cephalopod fossils were found at sites in Christian Malford, Wiltshire (162 million years old) and Lyme Regis, Dorset (195 million years old) in the UK and included preserved three-dimensional ink sacs. Biological tissues rarely survive in fossilised material as they are almost always quickly degraded by microorganisms. But some types of organic substances found in living organisms may last for long periods of time if they are polymeric - large and made up of multiple subunits - and have a tough cross-linked structure. One such substance is melanin, of which the form eumelanin - which takes a dark black or brown colour - is known to be a key chemical component of modern common cuttlefish ink.  Cephalopods use the dark-coloured ink to reduce visibility when threatened so they can rapidly escape without being caught. Mucus is also sometimes added to the ink allowing it to hold a form for a limited period of time, giving the illusion of ‘false bodies’ that act to distract predators from the real organism. Eumelanin remains were found to be well preserved in the ancient fossilised ink sacs through a number of different chemical tests. The maintenance of ink chemical composition over this huge period of time suggests that the use of ink as an anti-predator strategy has retained its evolutionary benefit for well over 160 million years and is fully optimised for its purpose. Ref: Glass K. et al., 2012. Direct chemical evidence for eumelanin pigment from the Jurassic period. PNAS Online before print [link]

In an extraordinary biological study, researchers have used chemical analysis to demonstrate that ink preserved in the remains of two cephalopod fossils that date over 160 million years ago to the Jurassic period is almost identical to that used by modern common cuttlefish (Sepia officinalis) today. The cephalopod fossils were found at sites in Christian Malford, Wiltshire (162 million years old) and Lyme Regis, Dorset (195 million years old) in the UK and included preserved three-dimensional ink sacs. Biological tissues rarely survive in fossilised material as they are almost always quickly degraded by microorganisms. But some types of organic substances found in living organisms may last for long periods of time if they are polymeric - large and made up of multiple subunits - and have a tough cross-linked structure. One such substance is melanin, of which the form eumelanin - which takes a dark black or brown colour - is known to be a key chemical component of modern common cuttlefish ink.  Cephalopods use the dark-coloured ink to reduce visibility when threatened so they can rapidly escape without being caught. Mucus is also sometimes added to the ink allowing it to hold a form for a limited period of time, giving the illusion of ‘false bodies’ that act to distract predators from the real organism. Eumelanin remains were found to be well preserved in the ancient fossilised ink sacs through a number of different chemical tests. The maintenance of ink chemical composition over this huge period of time suggests that the use of ink as an anti-predator strategy has retained its evolutionary benefit for well over 160 million years and is fully optimised for its purpose.


Ref: Glass K. et al., 2012. Direct chemical evidence for eumelanin pigment from the Jurassic period. PNAS Online before print [link]

Research using mice has revealed a new gene that plays an essential role in mammalian fertility: the PDILT gene encodes a protein that enables sperm to navigate their way through the oviduct and bind correctly to the egg during the process of fertilisation. The PDILT protein stimulates the correct folding of another protein called ADAM3, which is then localised to the outer membrane of the sperm. Without PDILT, the ADAM3 protein is not folded correctly or transported to where it is needed to be. Its critical importance was evident following the discovery that if its expression is ‘switched off’ in sperm, fewer than 3% of eggs become fertilised, in comparison with approximately 80% when the gene is active. Sperm lacking PDILT are not only unable to bind the egg fully, but find it difficult to navigate through the oviduct to get to it in the first place. The experiments also revealed that what are known as cumulus cells, which form a protective layer around the egg, aid in effective binding of the sperm to the egg and will help to rescue the binding difficulties caused by the absence of PDILT, enabling successful fertilisation. The next step will be to examine how the gene works in humans - from there, it may be possible to produce fertility treatments that could aid in making IVF more successful for those couples that are faced with low fertility.Ref: Durham University, 2012. Gene involved in sperm-to-egg binding is key to fertility in mammals. EurekAlert! News [link]

Research using mice has revealed a new gene that plays an essential role in mammalian fertility: the PDILT gene encodes a protein that enables sperm to navigate their way through the oviduct and bind correctly to the egg during the process of fertilisation. The PDILT protein stimulates the correct folding of another protein called ADAM3, which is then localised to the outer membrane of the sperm. Without PDILT, the ADAM3 protein is not folded correctly or transported to where it is needed to be. Its critical importance was evident following the discovery that if its expression is ‘switched off’ in sperm, fewer than 3% of eggs become fertilised, in comparison with approximately 80% when the gene is active. Sperm lacking PDILT are not only unable to bind the egg fully, but find it difficult to navigate through the oviduct to get to it in the first place. The experiments also revealed that what are known as cumulus cells, which form a protective layer around the egg, aid in effective binding of the sperm to the egg and will help to rescue the binding difficulties caused by the absence of PDILT, enabling successful fertilisation. The next step will be to examine how the gene works in humans - from there, it may be possible to produce fertility treatments that could aid in making IVF more successful for those couples that are faced with low fertility.

Ref: Durham University, 2012. Gene involved in sperm-to-egg binding is key to fertility in mammals. EurekAlert! News [link]