Cosmetic Dentistry : The Mayan Style

Mayan area   
Courtesy Simon Burchell, wikipedia 

Mayan civilization  flourished   in and around Yucatan peninsula in Central America for almost 3000 years.    It reached  glorious heights during AD 200-800. . Thereafter  it declined,  for   reasons  not clearly known.  Sudden climatic changes, earthquakes  or even epidemics could have triggered the decline.  Investigations are still ongoing and speculations are innumerable.    Archaeological excavations are being  conducted in several parts of the Yucatan and have yielded rich artefacts which are being subjected to scientific scrutiny.  The colourful collage that results from joining together the details derived from  historic artefacts and ecofacts  is simply awesome.  Thus we know that   Mayans lived in well organised city-states; they were a farming society  cultivating maize, cacoa, cotton etc.;  they wore elaborate headdresses adorned with colourful plumes; they had a pictorial  writing system and  a counting system  based on 20; they had extensive knowledge of herbal medicines. Above all they had drawn up calendars based on the movement of celestial bodies. It is often said that the  Temple of Kulkulcan   at Chichen Itza   was built taking into consideration  the sun’s location during the spring and autumn equinoxes. 

Artistic representation of the Mayan bejewelled teeth 
 in National Museum of Mexico 

Among the artefacts preserved in the Mexico city National Museum,   are skulls dating back to AD 700.  In many  of these skulls, labial teeth  are adorned with  inlays of gold or embedded with  precious stones.  These adornments could have  aesthetic/magical /religious  connotations.  That apart,  scientists  are  amazed at the exquisite craftsmanship. It is indeed astounding  how  shallow cavities are carved out on tooth surfaces  neatly and skilfully using primitive tools. Obviously the craftsmen had an excellent knowledge of dental anatomy. 

Even more surprising is the glue or cement that holds the gems in place.  What  miracle  glue did the Mayans use, that even after  centuries  some of these gems are held firmly  in place ?  An earlier

Courtesy: Reference 1

 analysis yielded information that the cement  contained large amounts of  phosphorous and calcium, with smaller amounts of iron, silicon and  magnesium.   Recently    Hernandez-Bolio and team studied  skeletal artefacts  excavated from      sites such  as  Holmul (Guatemala), Baking Pot (Belize), and the Copan Valley (Honduras).      They used  modern techniques  such as    Attenuated Total Reflectance Infrared Spectroscopy (ATR-FTIR) and Gas Chromatography coupled to Mass Spectrometry (GC–MS).  Eight dental specimens when subjected to these techniques revealed that the glue contained, pine resin and bitumen mixed with  extracts from the plants of  mint family. 

Primary biological role of these terpenoid  oleoresins,   exuded by trees like pine is to defend  against insects and pathogens. The Investigators  allude that  the  antibacterial and anti-inflammatory properties of these oleoresins  might have contributed to dental healing and  oral hygiene.  

More about oleoresins later

TAILPIECE:

The full compositional analysis of the cement/glue is yet to be completed.  Then there are other nagging  questions  seeking answers. What were the primitive tools used? Given that Mayans knew about intoxicating and hallucinating drugs, did they use any  herbal medicines as local anaesthetic  or a sedative ? 

REFERENCE

1.  Organic compositional analysis of ancient maya tooth sealants and fillings:  Hernández-Bolio  et al Journal of Archaeological Science: Reports  Volume 43, June 2022, 103435

2. 

Of Pests and Pest Management

Potato traces its origin to  the Andes, in South America.   Centuries ago, the humble crop crossed the Atlantic sea and reached Europe. Since then it  has travelled far and wide and has become ubiquitous. It is now  an indispensable   component in most of the  cuisines.  Easy to grow, this staple food  is  cultivated all over the world.  However  potato plants  have  an  alarmingly, powerful enemy:   the parasite Potato Cyst Nematode (PCN). The juvenile worms of PCN cling the potato sapling's tender roots and suck out  all the nutrients  causing the plant to wither and wilt. This has devastating effect on  the crop  yield.  Upto  80% reduction of the yield, and at times total crop loss  have been reported. 

PCN  cysts ( in yellow ) clinging to potato roots:
Courtesy: wikipedia 

PCNs  belong to the Globodera genus. These are  a class of obnoxious yet  very smart plant pests. These nematodes or roundworms  infest plants in the solanaceous family such as potatoes, tomatoes and eggplant.  Interestingly Globodera also trace their origins to the Andes, in South America. Definitely a case of coevolution.

PCNs come in male and female forms.   Once fertilised, the female dies, its bodily remains forming a protective hard cover  around the eggs. A single such cyst could contain upto 500 eggs suspended  in a thick viscous sugar syrup.    The  sugar is  trehalose, which  is a dimer of glucose.   The hard outer shell and the viscous syrup inside  jointly protect the eggs  from  all kinds of mechanical stress and preserve them intact for decades. The sugar also serves as an energy source. Thus  the cysts lie in wait patiently for  a signal  to hatch.   

Courtesy: Shenk et al 

That  the signal comes from the roots of plants belonging to the  Solanaceae family,  was known as far back as in 1923.  The tender roots of potato  exude a mixture of  chemicals. One of the chemicals, later  identified as  Solanoeclepin A  is a stimulant for  hatching  the PCN eggs.   This chemical, a terpene,  with the  formula  C27H30O9  has an equally  complex structure. The structure was elucidated in 1999  by   Schenk et al.

Solanoeclepin A  initiates a series of activities  both on the  outside and  inside of the PCN  cyst. First, solanoeclepin A induces  the  cyst  wall to become a bit leaky. This causes  trehalose  syrup to ooze out and water/moisture to  rush in, thus irrigating the eggs and  facilitating their hatching.  However as a part of survival strategy, all of the eggs are not hatched in one go.   Professor Benjamin Mimee  and his team point out that  this could be   to increase population persistence throughout growing seasons and to lower competition between hatched juveniles.

Though pesticides  are effective, poorer nations find it unaffordable. This where  the  efforts  of a  global team of scientists with Professors  Danny Coyne, Charles Opperman and  Baldwyn Torto  at   the helm prove valuable.  Collectively  they have hit upon a simple strategy:  wrap the potatoes  in banana  paper  and then  plant. The banana paper  absorbs most of the  exudates,  including solanoclepin A,   thus   preventing hatching signals reaching the PCN cyst.  One  of the rare instances of  humans  vetoing Nature in very simple terms. 

REFERENCES:

1. Analysis of survival and hatching transcriptomes from potato cyst nematodes, Globodera rostochiensis and G. pallida

2. Elucidation of the Structure of Solanoeclepin A, a Natural Hatching Factor of Potato and Tomato Cyst Nematodes, by Single-crystal X-ray Diffraction*

3. Wrap-and-plant technology to manage sustainably potato cyst nematodes in East Africa

COVID Vaccine Stories III: The Inequity Factor

By now all (scientists included) are  resigned to the fact  that  COVID-19  is here to stay  and  that we must learn to live with it.  We may not be able to eradicate SARS-CoV-2 as we did smallpox and polio.   The  pandemic might eventually shrink to an endemic state which  can be easily managed with vaccines. That again is a fervent hope. As of now the focus is to get  everyone doubly vaccinated  as fast  as possible.     

That a large percentage of global population is yet to be vaccinated,  adds to the worry. This  began as  an economic issue.  The Rich  and the Powerful nations competed  with each other to procure vaccine supplies for their citizens.  They  hijacked  enough and more supplies  while the poorer nations remained helpless, mute bystanders. It took  time for the Rich to realise  that unvaccinated  populations are fertile grounds for  new variants.  In other words nobody is safe unless everybody is vaccinated.  

Courtesy:wikipedia

Vaccinating entire global population is a daunting task indeed.  Even  if adequate amounts of vaccines are  made available, as is the case  now,  logistics of  the supplies reaching every remote corner before the expiry date remains a challenge. Most of the developing nations do have very  robust healthcare  networks in place while most of the underdeveloped  nations don't.  With the result that  as of 14th February  2022, though  globally 10.4 billion doses have been administered,  80% of African  population remains unvaccinated.   

Coronavirus will  continue  to mutate,  at times  in unpredictable ways.  Still, the  fact that there are several vaccines already in the market and many more in the pipeline  is certainly "a cause  for  hope  and optimism"  as  Nature Magazine summed up  in its  recent  Editorial:    "but with  a hefty dose of realism: the virus  will continue to circulate  and change, and governments must continue to rely on the guidance and advice  of scientists. We will not always be able to predict the virus's  path but we must be ready to adapt  with it."

REFERENCES

1. COVID-19 will continue but the end of the pandemic is near

2. No one is safe from COVID-19 until everyone is safe.

3. Tracking Coronavirus Vaccinations Around the World

4. Dear G20 leaders: Vaccine equity is a must for Africa

5. Coronavirus  is here to stay

6. COVID is here to stay: countries must decide how to adapt

7. Achieving COVID-19 vaccine equity means overcoming hesitancy

Covid-19 Vaccine Stories: II: The Inimitable Cuban Style

When Covid-19 struck, Cuba knew it will have to fight alone, because the sixty year old economic embargo by the mighty United States  prevented Cuba's access to US vaccines.  Undeterred the scientists at the Finlay Institute of Vaccines,  together with the Centre for Genetic  Engg. and Biotechnology Havana rose to the occasion.   In May 2021,  The Guardian prophesied that Cuba could become  the smallest country in the world to develop its own coronavirus vaccines. In spite of economic hardships,  the country  surged ahead. The prophesy  came  true.  Cuban Vaccines  Soberana 02 and Abdala registered +90% efficacy against Covid-19. Today more than 80% of Cuba's 11million population stands vaccinated  and    scientists  are  tweeking  Soberana-02 to meet the challenge of the Omicron variant.

In Spanish Soberana means Sovereign and Abdala is a famous Cuban patriotic poem. The Mambuses are patriotic Cuban soldiers who  have always fought for Cuba

Sobarina 02 is the first conjugate vaccine to be developed against SARS-CoV-2.   In conjugate vaccine technology, individual components elicit feeble immune response, but together they are  very powerful.  Soberana-02 contains  a fragment  of the viral spike protein of SARS-CoV-2 chemically linked to an harmless  piece of a protein snipped from tetanus toxin. These two fragments linked  in  a molar ratio of 6:1 is  adsorbed onto  alumina and suspended in an appropriate medium.  Abdla, developed by Centre for Genetic Engineering and Biotechnology,

Centre for Genetic Engg.and Biotechnology,
Havana, Cuba

Havana,   is simpler,   a different   fragment of the spike protein adsorbed onto aluminium hydroxide and suspended in suitable medium.  Such protein vaccines  do not require extreme refrigeration  and are cheap and easy to  manufacture. There are several other candidates in the Cuban pipeline including a nasal vaccine  Mambisa.

In Spanish Soberana means Sovereign and Abdala is a famous Cuban patriotic drama. The Mambises are those patriotic Cuban  soldiers who defended Cuba on several occasions.

In the meanwhile Cuba has embarked on vaccine diplomacy by exporting Soberana-02   and Abdala  to Venezuela,  Nicargua, Iran and Vietnam. It would like to extend this gesture of comraderie  to less privileged nations who are in dire need of the vaccine. For this World Health Organisation's has to give the nod.

Tailpiece

“Cubans either don’t meet the mark – or go way past it.”

(Words of General Máximo Gómez, a key figure in Cuba’s 19th-century wars of independence against Spain : Guardian  5th Jan. 2022)

REFERENCES

1. Cuba punches above its weight to develop its own Covid vaccines

2.Cuba soars to near top of COVID vaccination charts on decades-old bet

3. In world first, Cuba starts COVID-19 vaccine for toddlers

4. Cuba's bet on home-grown Covid Vaccines is paying off