Monday, 22 May 2017

Mary Anning's Fossils and the Cliffs at Lyme Regis

Mary Anning was a nineteenth century fossil collector and paleontologist who made important contributions to science. The fossils came from the Jurassic period and were obtained from the cliffs and beaches of Lyme Regis in England. The cliffs were once part of the seabed. Even today they contain a rich source of fossils.

Mary developed an impressive knowledge of local life in the Jurassic. Though she eventually became respected by geologists, she didn't receive as much attention as she deserved. She lived at a time when science was predominantly the domain of males. She also came from a poor family and had little social standing, which further hindered the attention that she received from the scientific community.




Mary Anning
 Unknown artist (created before 1842)
Public domain license


Mary Anning's Life


Mary was born in 1799. Her father died when she was only eleven, leaving his family in debt. Fortunately, he was a keen fossil hunter and had passed on his skills to his family. The family was short of money but were able to survive by collecting and selling fossils. The fossils became more than just a means of survival for Mary. She studied, analyzed, and documented her discoveries, moving out of the realm of being only a collector and into the realm of paleontology.


Mary's fossils were sent to scientists, museums, and private collections, but often the fact that she had discovered a particular fossil was omitted or forgotten. In addition, scientists sometimes presented her discoveries to an audience without acknowledging that Mary had found and prepared the fossil.


Life was often financially difficult for Mary, but there were times when she was better off than others. In 1817 a wealthy fossil collector became a supporter of the Anning family. He sold his own fossil collection and gave the proceeds to the family. He was also careful to attribute their discoveries to them. This helped to publicize the family's activities as well as to aid them financially, at least for a while. As her life progressed, Mary's fortunes rose when a commercially desirable fossil had recently been found and fell when there was a prolonged gap between significant discoveries.




An ichthyosaur skeleton
Photo by Adam Dingley
CC BY-SA 3.0 License


Later Life


Mary eventually become recognized as a dedicated and careful fossil collector by scientists. In 1838 she received an annuity from the British Association for the Advancement of Science. In addition, she received a stipend from the Geological Society of London. These regular sums of money were probably very helpful for her. Unfortunately, Mary died from breast cancer in 1847 while she was still relatively young. The Quarterly Journal of the Geological Society published her obituary. The society didn't admit women until 1904.



Lyme Regis


Lyme Regis is a town on the southern coast of England. Its coastline forms part of a World Heritage Site. The cliffs and the beach beside them are a rich source of fossils. Even 170 years after Mary's death, people successfully hunt for fossils in the area. The cliffs are eroding rapidly, a process that continually adds new fossils to the beach. It also means that visitors need to be careful that they don't get hit by falling pieces of rock.


There are two versions of the painting of Mary Anning shown above. The one that I've included is reportedly the earlier one. The second version is similar but not identical and is said to be a copy of the first one. It's important to note that using a pick to hammer the unstable cliffs as Mary apparently did at Lyme Regis is dangerous. She nearly died in a landslide that killed her dog, though I don't know the immediate cause of this event.




A cast of a plesiosaur
Photo by Adrian Pingstone
Public domain license



Mary's Discoveries


The Jurassic period lasted from approximately 199.6 million years ago (mya) to 145.6 mya. Mary found many fossils from this time period. The first major discovery happened when she was only a child. When she was twelve, her brother Joseph found the skull of an ichthyosaur. A few months later Mary found the rest of the animal. This was the first complete ichthyosaur skeleton to be discovered. Ichthyosaurs were marine reptiles that had a fish-shaped body.


Mary was also the first person to discover a complete (or almost complete) plesiosaur skeleton. Plesiosaurs were marine reptiles with a long neck, a small head, and flippers. Another important discovery was a skeleton of Pterodactylus macronyx, which is now known as Dimorphodon. The animal was a type of pterosaur. Pterosaurs were flying reptiles with wings. Mary also found other interesting and often significant items, including fossilized ink sacs that resembled those of today's octopuses and squid.


The discovery of coprolites demonstrates how Mary's work helped scientists. She noticed that coprolites—or bezoar stones as they were known then—were often found in the abdominal region of ichthyosaur specimens. She also noticed that the stones contained fossilized bones of fish and other creatures. Based on these facts, a geologist named William Buckland proposed (correctly) that the stones were fossilized feces.


The interest in Mary Anning's work has been revived in recent times, and rightly so, I think. Her discoveries were important in their own right and also enabled scientists to discover more about life in the Jurassic period.



References 


Mary Anning biography from the San Diego Supercomputer Center website (which includes biographies of female scientists)


The Three Mary Annings from the University of Waterloo


Information from UCMP (University of California Museum of Paleontology)

Tuesday, 16 May 2017

A Biodegradable Sanitary Pad Based on a Seaweed Ingredient

The disposal of sanitary pads (or napkins) and related products creates a big environmental problem that needs to be solved. Women need some kind of protection during menstruation. A sanitary pad is a popular choice, but unfortunately most brands are not biodegradable and collect in the environment as waste after use. Researchers at the University of Utah have created a new pad which they say is effective, comfortable, and safe for the environment. It relies on a substance from brown algae or brown seaweed for its ability to absorb liquids.



`
Brown Algae in Norway
Photo by Ximonic, CC BY-SA 4.0

Each year, nearly 20 billion sanitary pads, tampons and applicators are dumped into North American landfills. (Quotation Source: University of Utah News Release)

Biodegradable Products


Biodegradable products would seem to be a solution for the environmental problems cause by discarded sanitary pads. There are problems with at least some of these products, however. Complaints include the fact that they don't absorb enough fluid, don't fit properly, or are uncomfortable. The researchers at the University of Utah have created what they believe is a "better sustainable sanitary pad".


                            Candida albicans growing on agar in a yeast form
                                            and in a filamentous form.
                                       Photo by Garnhami, CC BY-SA 4.0

The SHERO Pad 


The University of Utah researchers say that their product is thinner than other biodegradable pads. It's known as a SHERO pad and is composed of four layers. The outer layer is made of the same material as tea bags. Below this is a cotton layer that helps to absorb liquid. Next is a highly absorbent substance called agarose, which is obtained from brown algae. The last layer of the pad is made from corn and serves as a moisture barrier.

Agarose is a polymer and a polysaccharide that is obtained from the agar in seaweed. Polymers are long molecules made of repeating subunits. In a polysaccharide, the subunits are sugar molecules. In biology, the word "sugar" refers to a family of chemicals instead of just sucrose, or table sugar. 


Agar (sometimes known as agar-agar) is a substance obtained from certain algae that forms a gel when added to water. It's often supplied to the public in a dried form as a powder or flakes. When water is added to the dried agar, the gel is produced. Agar is used as a vegetarian substitute for gelatin. It's also a common substrate for bacteria in the petri dishes used in biology and medical labs. Agarose is one of the chemicals in agar that is responsible for its ability to form gels.


The inventors of the new pad say that once discarded it will break down within forty-five days to six months. The difference in time presumably depends on the environmental conditions. The pads are said to be completely degradable, unlike some pads that claim to be so. 
The average woman will menstruate for about four decades and use an estimated 16,800 sanitary pads or tampons in the process — that’s 250 to 300 pounds of waste. In the U.S. alone, some 12 billion pads and 7 billion tampons are disposed of annually. (Quotation Source: grist.org)

Creating and Selling the Pad


The SHERO pad was created for women in developing countries, especially those in Guatemala. In fact, its creation was stimulated by a request from a Guatemalan advocacy group for women and children. Safe drinking water and public sanitation are sometimes unavailable in the country, especially in rural areas. Discarded sanitary napkins add to the pollution burden.

The researchers have launched a startup company and hope to have the product available in Guatemala and for sale in the United States within a year. They also say that it may be possible for communities in some parts of Guatemala to produce the pads themselves from local materials, as long as they have a grinding stone and a press. It will be interesting to see how practical this process is. It will also be interesting to see if the pads are as effective and as biodegradable as the researchers believe.



Reference

University of Utah News Report 

Saturday, 6 May 2017

Maintaining and Controlling the Blood-Brain Barrier

The blood-brain barrier, or BBB, is a layer of cells that stops specific substances in the blood from entering brain tissue. This is an essential job, since the brain controls our body and keeps us alive. It must be protected from harmful materials. Sometimes, though, researchers are frustrated when a medication that could help a neurological problem is unable to enter the brain due to the presence of the BBB. Understanding how the barrier works and learning how to safely modify its actions are important endeavours.



Salmon contains DHA, which helps to keep the
blood-brain barrier strong. (Public domain photo)


The Blood-Brain Barrier


The blood-brain barrier consists of tightly packed endothelial cells that line the capillaries around and inside the brain. The membranes of adjacent cells in the barrier are joined by so-called "tight junctions", which block the passage of virtually all materials. Materials are forced to travel through the cells in the barrier in order to enter the brain tissue. This enables the cells to have some control over the passage of the materials.


The blood-brain barrier does allow some substances to enter the brain, including nutrients such as oxygen, glucose, amino acids, and water. Brain cells need these chemicals in order to survive. Lipid-soluble substances can also pass through the barrier. Bacteria, other pathogens, and substances that could act as neurotoxins are blocked, however.



Role of an Omega-3 Fatty Acid


Researchers at the Harvard Medical School have recently explored the role of a specific type of omega-3 fatty acid in the blood-brain barrier. Their research has shown that the chemical is important for maintaining the integrity of the BBB and enabling it to block the movement of substances. The fatty acid in question is docosahexaenoic acid, or DHA. It's found in oily fish and certain algae. The researchers have found that the endothelial cells in brain capillaries have two to five times more DHA than the ones in lung capillaries.


The blood-brain barrier protects the brain. 
(Public domain photo)


A Transporter Protein


The endothelial cells lining blood vessels around and in the brain contain a protein known as Mfsd2a. This protein transports lipids, or fatty materials, including ones containing DHA. It moves the lipids with DHA into the membrane of the endothelial cells, which keeps the BBB strong. 

The protein also inhibits transcytosis in the cells. This is a process in which a substance enters a cell via vesicle formation (endocytosis), moves to the opposite membrane of the cell, and then leaves the cell in another vesicle (exocytosis). A vesicle is a small, membranous sac. The cell has other ways to transport materials, but some substances must move through the cell by transcytosis.


The Harvard researchers have bred mice with a mutated form of the gene that codes for the Mfsd2a protein. The mutation in the gene causes an altered protein to be produced. The altered protein can no longer transport lipids containing DHA. As a result, the mice develop "leaky" blood-brain barriers which allow the passage of materials that are normally blocked. In addition, the formation of the vesicles needed in transcytosis is no longer inhibited, which also increases the passage of materials. The same results occur when mice lack the Mfsd2a protein entirely.



Human Applications


Assuming that the process discovered in mice works the same way in humans, it might be useful to us. If we could temporarily block the activity of the Mfsd2a protein, we might be able to send medications for treating Alzheimer's disease, brain cancer, strokes, and other conditions into the brain. The problem is that we need to do this without allowing harmful substances into the brain, or at least while limiting their entry. Hopefully we will discover how to do this as we learn more about how the blood-brain barrier works.


Research Reference


Role of omega-3 fatty acids in keeping the blood-brain barrier closed

Sunday, 30 April 2017

Wax Worms and Moths: Caterpillars That Digest Plastic Bags

A preserved greater wax moth
Photo by Sarefo, CC BY 3.0 License

A Caterpillar That Eats Plastic


The wax worm (or waxworm) is a caterpillar that feeds on the wax in beehives, among other things. Scientists in Spain have just made what could be a very useful discovery about the caterpillar's abilities. It can eat and digest the polyethylene that is used to make plastic bags. This means that it might be useful in reducing plastic pollution. Plastic waste normally breaks down very slowly and is harmful to many organisms, especially in the ocean where much of the waste collects.

The wax worm that's being investigated by the researchers is the larval form of an insect known as the greater wax moth, or Galleria mellonella. The discovery that the caterpillars can digest polyethylene was made by accident. The insects were being stored in plastic bags. The researchers noticed that multiple holes were appearing in the bags and realized that the caterpillars were actually eating the plastic. They later discovered that the insects change the polyethylene into ethylene glycol.



The Greater Wax Moth


The greater wax moth is native to Europe and Asia but has been introduced to other areas. It invades beehives as well as stored honeycombs from the hives. A honeycomb is made of wax produced by the bees' wax glands and contains hexagonal chambers that are used to store honey and pollen. The female wax moth lays several hundred eggs inside a chamber or in cracks in a hive. 

According to agricultural experts, wax moths are rarely successful in healthy beehives. They can be a big problem in unhealthy hives where they are able to reach the honeycomb without resistance from bees, however. They can also be a problem for honeycombs taken out of a hive.

The wax moth's eggs hatch into larvae, or caterpillars. The larvae are white, brown, or grey in colour. They form tunnels in the honeycomb by chewing through the wax. They line these tunnels with a web of silk.

Eventually a larva surrounds itself by a silken cocoon and becomes a pupa. Inside the pupa, the larva undergoes metamorphosis and becomes an adult. The moth leaves the hive and breeds, enabling the life cycle to begin again. 


Digesting and Recycling Plastic 



The plastic bags used to package store goods for consumers are usually made of polyethylene. The ability of wax worms to digest the polyethylene could be very helpful. Researchers don't yet know whether the caterpillar is digesting the plastic with enzymes that it produces or whether bacteria in its gut are doing the digesting, as happens in Plodia interpunctella. This is another moth whose larvae eat wax from honeycomb. It's classified in the same family as the greater wax worm and is commonly known as the Indian mealmoth. Other researchers have discovered that the larva of a particular beetle can digest plastic. The lesser wax worm eats beeswax, but as far as I know researchers haven't explored whether it can digest polyethylene.

Reducing the use of plastic bags or at least recycling them is an important process right now. Some stores are charging for plastic bags to reduce their use. Although curbside recycling programs generally don't accept the bags, some places do. A supermarket near my home has a collection bin for recycling plastic bags, for example.

In the near future, we might be recruiting specific insects and bacteria to break up our plastic. This almost certainly won't reduce the need to reduce the creation of plastic pollution, but it could be a great aid in removing the waste that has been or is created.



References


A new solution for plastic waste?
The greater wax moth

Saturday, 14 March 2015

Mallard Ducks - Interesting, Attractive and Entertaining Birds

The mallard duck is an old friend of mine. It was the first duck that I learned to identify as a child and has been part of my life ever since. The bird's confidence around humans and its relative abundance compared to other ducks attracted me both in Britain, where I grew up, and in Canada, where I live now.

Today I always stop to say hello when I find mallards on my walks. Like the pair in my photo below, they don't seem to be too impressed with my greeting, although they tolerate my presence. I never feed them, which I'm sure is the reason for their lack of enthusiasm.


Identifying a Mallard

A male and female mallard that I met on a walk
Photo by Linda Crampton
The male mallard is a handsome fellow when he's wearing his breeding plumage. His head is a rich and iridescent green and his bill is yellow. The white neck ring above a beautiful chestnut brown chest and the silver sides add to his attractiveness. He also has a black curl on his "tail".

The female mallard is attractive too, although her mottled brown coloration and orange and brown bill are less impressive than the male's. Both birds have a blue patch on their wings called a speculum. The speculum is sometimes visible when the wings are folded.

Mallards hydridize readily with other ducks, so some birds are hard to identify. In addition, after the breeding season has finished, mallards lose their bright colour and the ability to fly for a few weeks as they molt. The effect is most noticeable in the males. At this stage the ducks are said to be in their eclipse phase. This is a dangerous time for the ducks, since it's harder for them to escape from predators. They tend to stay hidden from view during this phase and are seen less often.


Mallard Habitat and Diet


It's not hard to find mallards, at least where I live. Ponds and lakes in nature reserves, wild areas, parks and golf courses are good places to look for the ducks. They can also be found in marshes, streams, temporary wetlands on farms, roadside ditches, reservoirs and estuaries. 


An upended male mallard feeding
Photo by David Wagner via publicdomainpictures.net
Mallards are dabbling ducks, which means that they feed by upending their body and dipping their head into the water to find food. They rarely dive but do so occasionally. They also feed on land. Mallards are omnivores and eat aquatic and land vegetation, seeds, grain, insect larvae, shrimp, snails and even earthworms.They are often more than willing to accept handouts from humans.

There are many potential problems caused by humans feeding waterfowl. It's best not to feed the birds, but it's an enjoyable activity, expecially for children. Please give a healthy handout if you decide to feed ducks or any other birds. Grain intended for wild birds is good; bread isn't. Both supermarkets and pet stores sell grain for wild birds. Try to buy the freshest grain possible.


Courtship Displays



A female mallard with her speculum visible
Photo by Antranias via pixabay.com
I always enjoy watching mallards. Their behaviour is very interesting, particularly when they start performing their mating displays in the spring. Recording and analyzing this behaviour is a good project for beginning naturalists because it's easily observed. It's also entertaining for everyone.

Mallard courtship is easiest to observe in open areas that have a group of ducks. Luckily, the birds aren't shy about performing in public. When many birds are present, the ducks can get very excited and often put on a great show.


Some More Mallard Facts

  • Only the female mallard quacks. The male makes rasping sounds instead. He also emits a whistle during the mating display.
  • All domestic ducks - except for the Muscovy duck - evolved from mallards.
  • The mallard"s natural range is the northern hemisphere, but it's been introduced to the southern hemisphere as well.
  • According to the Cornell Lab of Ornithology, mallards can fly up to an estimated 55 mph.
  • The longest known lifespan of a mallard duck is 27 years. Most wild ducks live for a much shorter time, however.

Sunday, 18 January 2015

Angelica - An Interesting and Useful Culinary Herb

Angelica is an aromatic culinary herb that is also used in folk medicine. The herb has the intriguing scientific name of Angelica archangelica, which reflects one of two traditions. One is that the herb blooms on the feast day of Archangel Michael, or Michaelmas, which falls on September 29th in the modern calendar. Another is that the Archangel first informed humanity about the plant's medicinal uses.

Most people that have heard of angelica probably think of it in the form of candied stems, which are used as cake and pudding decorations. The plant can also be used as a vegetable and as a flavouring agent. Its pleasant scent and flavour are very nice additions to food.

The Angelica Plant
Angelica archangelica
Photo by Christian Fischer,
CC BY-SA 3.0

Angelica belongs to the Apiaceae family, which also contains parsley, dill, fennel, carrot and celery. Chinese angelica or dong quai belongs to the same family. 

Angelica is a tall plant that can reach a height of six feet or more - sometimes much more. Its stem is hollow and ridged. The plant has compound leaves with toothed leaflets. The leaves are bright green and shiny.

The small yellow, white or pale green flowers of angelica are born in a structure called an umbel. In an umbel, the flowers are located on the ends of short stalks (or pedicels) that all branch from the same point on the flower stem. The pedicels look rather like the ribs of an umbrella that has been turned upside down. The fruits of angelica are small, yellow-green and oblong.

Angelica is native to Northern and Central Europe and to Asia but has been introduced to other areas. It grows in both a wild and a cultivated form and requires moist soil. The plant is a biennial and flowers in its second year.

Culinary Uses of Angelica 

The roots, stems, leaves, flowers and seeds of angelica are all edible. Of course, it's vital to be absolutely certain of a plant's identity when foraging for wild plants. This is very important when a person is searching for wild angelica. The Apiaceae family contains poisonous plants as well as edible ones. 

Angelica leaves
Photo by Doronenko,
CC CY 2.5
Fresh angelica is used as a raw salad green or as a cooked vegetable. The leaves are added to fish, poultry, savoury stews and soups. They are also added to stewed fruit dishes, such as those containing plums, rhubarb or gooseberries, where they reduce tartness and the need for sugar. The oil in the roots and seeds is used to flavour liqueurs, jams and jellies. The stem is boiled with sugar to make a candied cake decoration or a sweet treat.

Health Effects of Angelica

Angelica was once used as a protection against harmful spells and as a cure-all for disease. Today a tea made from the plant's leaves is said to relieve digestive upset. This claim hasn't been scientifically proven, although there are suggestions that it may be correct. It's important that anyone who wants to eat an edible herb in more than food quantities checks with their doctor first, however. Some plants contain chemicals that interfere with certain medications or aren't suitable for people with certain medical conditions.

Another thing to watch out for with plants belonging to the genus Angelica is that they contain chemicals called furocoumarins. These chemicals increase the sensitivity of the skin to sun damage when they come into contact with the skin and may cause dermatitis at the same time.

Even when it's not being used medicinally, angelica is a very nice herb for a garden or a kitchen. Herbs can add interest and flavour to foods and may have health benefits, too. I love adding them to my food.

Tuesday, 4 November 2014

Deadly Salamander Fungus Could Spread to North America

A deadly fungal disease has spread from Asia to Europe, killing large numbers of salamanders. The disease could easily spread to North America via the pet trade. Amphibians already have to contend with the fungus Batrachochytrium dendrobatidis, also known as Bd, which is having a devastating effect on amphibians around the world. This fungus has caused some species of amphibians to become extinct. Now salamanders are being attacked by a related fungus, which researchers have named Batrachochytrium salamandrivorans.

A fire salamander; photo by Didier Descouens,
CC BY-SA 3.0 License
The newly discovered fungus gained attention when it devastated the population of wild fire salamanders (Salamandra salamandra) in the Netherlands. Facts about the fungal infection known so far include the following:
  • Salamanders in Asia that are infected by the fungus don't appear to be suffering any ill effects and have likely developed some degree of resistance to the fungus.
  • Lab tests have shown that the fungus affects salamanders and newts but not frogs or toads.
  • No North American animals have been shown to be infected by the fungus at the moment. 
  • Given the large number of pet salamanders and newts transported into North America, some researchers think that the fungus is likely already present on the continent. 
  • In lab tests, all specimens of a newt commonly kept as a pet in North America died when exposed to the fungus.
  • The same observation was made in relation to a wild newt with a widespread distribution in North America.
B. salamadrivorans grows in a salamander's skin. It's not known how it kills the salamander, but it may work by a similar mechanism to B. dendrobatidis. Many (but not all) amphibians have lungs, but these aren't very efficient. Much of an amphibian's oxygen is obtained through its skin. B. dendrobatidis interferes with respiration and the uptake of water and minerals. The presence of the new fungus in North America could be very bad news indeed.