Notes from around the World.

According to Global Forest Watch, 16 million hectares of tropical forests have  disappeared in 2017 alone.   Anthropogenic activities are the major  causes  for this green cover loss.    For example  take the case of Colombia.  Situated in  the north western corner of the South American continent, Colombia  ranks high among megadiverse countries. According to the Convention on Biological Diversity website,   Colombia  ranks first in bird and orchid species' diversity and second in plants, butterflies, freshwater fishes and amphibians. With 314 types of ecosystems, Colombia possesses a rich complexity of ecological, climatic, biological and ecosystem components.  Colombian   President recently asserted that biodiversity is to Colombia what oil is for the Arab countries. 

Cocora Valley, Colombia:
Courtesy: wikipedia

But ever since the  ultraleft guerrillas, the FARC, (Revolutionary Armed Forces of Colombia), signed the  peace treaty with the Colombian govt.  and vacated the valleys and  forests (which were their habitat for 50+ years) Colombia's  ecological wealth has been fast disappearing. Because  urban developers want to clear the forests to set up housing, industrial and commercial projects and  of course  timber is  a source of easy money. 

MS Explorer sank in Antarctica 
in 2007 after hitting an iceberg
Courtesy: wikipedia

An equally disturbing   situation is unfolding in Antarctica . The Antarctica Treaty was initiated  in 1959 with 12 nations.  Later this number grew to  53. According to the Environmental Protocol the participating countries committed themselves to protect and cherish the ecosystem and use it only for science and peace.  All the  signatories  were on the same page while signing, but no longer so. Geopolitics is threatening the pristine continent because of  speculations on  the continent's stock of fish and  minerals as every nation wants a share.   Recent reports state  that in  Ile aux Cochons, an Antarctica island,  penguin population has declined by 90% in a span of 3 decades for reasons as yet unknown.   

               Deepwater Horizon Disaster                      
Courtsey: wikipedia

Meanwhile the United States has  relaxed its Ocean Policy.  Earlier  administration had put stringent restrictions on offshore activities  after the 2010 Deepwater Horizon  Disaster  in the gulf of Mexico.   That disaster,  an explosion  in the deep sea  oil rig, caused  134 million gallons of crude oil to spew out into the Gulf of Mexico causing environmental damages to the tune of   17.2 billion dollars. This damage has not yet been contained nevertheless   US Govt. has decided to revoke the restrictions and   promote offshore drilling for gas and oil  over approximately 78 million acres offshore. The region-wide lease sale  is scheduled for Aug. 15, 2018. 

We were just 1 billion people in the year 1800 and currently  register 7.6 billion and by 2100 the number will touch 11 billion.  Population challenge is compounded  by shrinking villages and booming urban spaces. 70% of the global population will be city dwellers by 2050.   China, India and Nigeria are expected to lead in this sphere.  Sure enough  anthropogenic activities associated with urbanisation will steadily and rapidly deplete natural resources.  Who should be concerned, Man or Mother Nature?  Nature has been through 5 cataclysmic mass extinctions, it can easily survive one more. Professor Reinhard Huttl at the Helmholtz Institute for Earth and Environment  observes wryly that Earth has enough  generative power to tide over  any disaster, it is us humans who are in danger. 

REFERENCES:

1. Reform the Antarctic Treaty : Nature editorial 14 June 2018,pp161
2. Watch over Antarctic waters: Cassandra Brooks et al,   Nature 14 June 2018 pp177-180 
3. Antarctica: Nature Insight 14 June 2018 pp 199- 241(Several articles)
4. Last King Penguin colony in the world drop by 90%

Magical Realism ? (with apologies to García Márquez)

Looks frosty on the roll, invisible on the job  that is how 3M company  advertises its product, the Magic Tape.  3M  came up with  transparent cellophane sealing tapes in the thirties. If that was a huge success, then   the Magic tape introduced in the  early sixties was indeed a  roaring success.  The convenience of  writing  over the Magic Tape  with a pen or pencil  or marker  increased  its popularity immensely. Today   MT has become  an integral part of every day life for everybody  - children, adults ,artists, executives,  housewives ……… .  3M soon designed  a convenient tape  dispenser too. Besides the magic tape  3M has  a whole series of  tapes in its Scotch portfolio, to suit any need/emergency. Particularly impressive are the colored,  patterned  and glitter  tapes.  The post-it  is also currently available in tape form.  All  these  are tapes which stick onto a surface when you apply a little  pressure( thumb pressure will do) and hence are also called  Pressure SensitiveTapes(PSTs).

       

But try peeling off the  tape,(exclude the post-it ) and you get a tutorial on magical realism. The tape pulls off a layer of the  surface it  is attached to.   Amazingly this worked like magic and   fetched  Andrei Geim and Kostya Novoselov   Nobel Prize in Physics in 2010  for the discovery of graphene.   In fact the Nobel committee made a mention of the playfulness of the scientists and their   process:  Playfulness is one of their hallmarks, one always learns something in the process and, who knows, you may even hit the jackpot. Like now when they, with graphene, write themselves into the annals of science. The  tape dispenser used by Geim and Novoselov   is  currently an exhibit  in the Nobel Museum, Stockholm.

But  reality remains.  Such tapes are used as short term damage control agents  to hold together  heritage materials or artworks.  By the time  authorities get down to  extensive restoration work, the  band-aids are often  discolored and/ or are  irretrievably  stuck to the surface.  Confronted with this  challenge, Professor Baglioni of the department of Chemistry, University of Florence   came up with a unique solution.    He and his team  “addressed the  issue from a physicochemical perspective”.

 

Professor Baglioni and his team  found that the   most popular PSTs used for damage control of artworks are    FilmoplatP (FPP), MagicTape (MT) and ordinary tape(OT).  In all the three  the adhesive is  acrylic based,  while the backing (tape material)  was cellulose for FPP,  cellulose acetate for MT  and  polypropylene for OT.   The team  had to design a peeling process restricted to the surface area of the tape  so that surrounding areas remained unaffected.  They solubilized a mixture of assorted organic solvents  in  water  using a detergent called  sodium dodecyl sulfate . The detergent ensured that the organic solvent mixture remained as nanosized droplet in the aqueous medium. Hydrogels, which are polymeric scaffolds with high affinity for water,  when immersed  in this medium,  absorbed  the same.    The swollen hydrogel was cut into strips of  required size and    applied over  the tapes. The solvents  slowly penetrated the backing  and in less than  half an hour  the tape could be easily pealed off.  

References

1. Scotch Products for consumers
2. Nobel Prize for Physics 2010
3. Restoration of paper artworks with microemulsions confined in hydrogels for safe and efficient removal of adhesive tapes. 

When Nature does an alt+ctrl+del

Survival instinct  guides a species either to avoid if possible  or adapt to a situation.   Euphydryas editha, a species of checkered butterflies  learned the hard way that in evolution there are no shortcuts.    Here is how the  story unfolds .  

Euphydras editha
(Walter Siegmund: wikipedia)

Collinsia parviflora  
(Walter Siegmund: wikipedia)

The setting is  Sneider Meadows, Nevada, USA.  In the opening scene evolution has enabled  E. editha butterflies  to forge a symbiotic relationship with Collinsia parviflora, a local annual plant species.   There is a mismatch between the life cycles of the host and the guest but they have learned to live with it. Often the plant withers before the adult butterflies emerge from the larvae with the result that baby butterflies are forced to starve. Mama butterflies, as Singer et al point out   thus "face a trade off between maternal fecundity and offspring survival" .    

Plantago lenceolata 
(Sannse: wikipedia)

And then humans intervened in the eighties.  But let us be fair to ourselves;  E.editha and  C. parviflora   were far from our minds.  We were interested in converting the barren wilderness  into a lush green grazing ground for cattle by  planting the  nutritious herbal species  Plantago lanceolata.   The newcomer   grew  and spread quickly. It looked greener, healthier and perhaps more attractive than the Collinsia. Seduction and betrayal followed,  E.editha  shifted its allegiance completely from Collinsia to Plantago. And why not?  Plantago is a perennial plant and E.editha  need no longer  worry about infant mortality from starvation.  

This went on for sometime. Then disaster, human intervention of course ,  struck. The  meadow changed hands and new owners didn't want it to be a cattle ranch. Wild grass grew tall and dwarfed the Plantago making its leaves  6 degrees cooler than the ambience. E.editha larvae couldn't withstand the cold and the species was pushed to the brink of extinction.  Indeed Sanger and Parmesan who were closely monitoring the butterfly population for decades  couldn't spot any during 2008-2012.    It seems to have taken another year for Nature to effectively reset the whole  program. In 2013-14 the butterflies reappeared, but  this time solely feeding on old buddy Collinsia. 

References

1. Plantain (Plantago lanceolata) – a potential pasture species

2. Rapid human induced evolution of host-insect associations Singer et al Nature 366, 681-683 (1993)

3. Lethal trap created by adaptive evolutionary response to an exotic resource. Singer et al Nature 357, 2018, pp 238-241

4. Human influences on evolution and the ecological and societal consequences. 

Insulin Resistance: The Fishy Side

Astyanax  mexicanus also known as Mexican tetra is a small fish not more than 12cm in  length.  However the species  has attracted the attention of evolutionary biologists since  the time of Darwin. The natural habitat of  A. mexicanus are   dark caves and crevices in  the rivers of Texas  and    eastern Mexico.   This aquarium fish  is not just blind;  it has no eyes at all.  According to Darwin the species would have started out as eyed variety then over  millions of  generations  the  dark habitat could have bestowed  the evolutionary advantage of blindness.  After all what use are eyes when the surroundings is pitch dark ?  The uptown river dwelling cousins of A.mexicanus are blessed with eyes.   Darwin's wrote in Origin of Species (1859) :  

By the time that an animal had reached, after numberless generations, the deepest recesses, disuse will on this view have more or less perfectly obliterated its eyes, and natural selection will often have affected other changes, such as an increase in the length of antennae or palpi, as compensation for blindness.  

Astyanax mexicanus, Characidae, Blind Cave Tetra; Staatliches Museum für Naturkunde Karlsruhe, Germany. courtesy: wikipedia 

29th March issue of Nature, carries another  astounding piece of information about A. mexicanus  reported by  Riddle et al.  For as yet unidentified evolutionary  reason,  the cave dwellers  maintain very high blood glucose level and are  insulin resistant.   What is even more  intriguing is that  insulin is a growth hormone too and blocking its pathway   should have resulted in stunted growth and  low body fat. Also  high glucose level in blood should have led to extensive glycation of proteins  and thus irreparable   tissue damage.  But whichever way you look at   their  health report  card, A. mexicanus  populations are not in the  least  affected.  They grow to a full length of 12cm,  are  very fatty,  live upto a ripe old age of 14 years,  and show no  tissue damage whatsoever. There are enough evidences to suggest that  insulin resistance is a genetic disorder.   Using CRISPER-Cas gene editing technique, the team found out about  a mutation in  insr gene (insulin receptor gene). The   INSR gene codes for a specific protein chain  which eventually shapes itself as the   insulin receptor on the  surface of cells-  part of it inserted inside  and the other part as stub protruding  outside which  binds  insulin.  Because of the mutation in the gene,  the  protein chain  is improperly formed  thus rendering it incapable of  binding insulin.  Such a state, described in mammals as  insulin resistant Type II diabetes  is  a major health hazard for humans. Precisely for that reason A mexicanus  has now captured the attention of  biomedical researchers.   

Effect of insulin on glucose uptake and metabolism. Insulin binds to its receptor (1) which in turn starts many protein activation cascades (2). These include: translocation of Glut-4 transporter to the plasma membrane and influx of glucose (3), glycogen synthesis (4), glycolysis (5) and fatty acidsynthesis (6).Courtesy: wikipedia

Glucose enriched blood could have evolved as an instant-food-reserve trait to compensate for the food scarcity in the dark recesses. But how is  insulin resistance  decoupled from the debilitating consequences of high blood sugar? Answer to this question will be a boon to mankind.   

References:

1. The complex origin of Astyanax cavefish

2. Blind Cave fish beat back Diabetes symptoms that would kill people

3. Insulin resistance in cavefish as an adaptation to a nutrient-limited environment: Riddle et al Nature: 29th March 2018. Vol.555, pp647-651

4. Genetic basics of insulin resistance and its role in type 2 diabetes pathology

Eat Less - To stay young, to live long

Metabolic slowing and reduced oxidative damage with sustained caloric restriction support the rate of living and oxidative damage theories of Aging.  That is the  title of a recent   paper in Cell Metabolism (1).  Well it is the scientific way of saying   eat less and you may stay young and healthy for a long time.     

Currently there are two accepted  hypotheses concerning mammalian aging.  In 1928 Raymond Pearl advocated the concept of Rate of Living, which essentially stated that the length of life depends  inversely on the rate of living; in other words faster the growth, shorter the duration of life.  Thirty years  later  Denham Harman proposed  Aging: A theory based on Free radical and Radiation Chemistry  which is  currently known as the Oxidative Damage  Theory of Aging.  Food is digested by an oxidative pathway and  the process naturally spews out Reactive Oxygen Species (ROS) - superoxide, hydrogen peroxide and hydroxyl ion- as byproducts. Unless removed from the system  by antioxidants,  ROS can chemically hurt proteins, lipids, and DNA. This chemical damage manifests itself as the  phenomenon of Aging.  Club the two hypotheses together and the recipe  for  extending  youth and longevity.   
  
Redman et al conducted a rigorous study spanning two years. Of the 435 healthy normal individuals  screened initially,  73  (male and female) were finally enrolled for the experiment. They were divided into two groups the CR (Calorie Restriction) group and the other AL (Ad Libitum) group. The CR group ate prescribed meals as per protocol, while members of the  Ad Libitum group true to its label were allowed to eat as they please.  For the CR group calorie intake was gradually reduced by 15% without compromising on the essential nutrients.  The CR group registered an  average  weight loss of  8.7kg, while the AL group gained 1.8kg in the same time frame.   The excretion of  Isoprostanes, found in urine  are the markers and mediators of oxidative stress  which was found considerably reduced in the CR group. 

Tailpiece:

Dr Luigi Fontana   says  what is important is  an healthy life style that includes  nutritious diet and  adequate  exercise;  nothing in the extreme.  "Don't make your life miserable by counting every single calorie" he adds.   

Also see earlier columns  " Blame it on Food" and  "Ageing Gracefully" 

References:

1. Metabolic slowing and reduced oxidative damage with sustained caloric restriction support the rate of living and oxidative damage theories of Aging.  
Redman et al Cell Metabolism 27,1-11 April 3 (2018 )

2. Calorie restriction in humans: an update 

3. The Hunger Gains: Extreme Calorie -Restriction Diet shows anti aging results : Scientific American February 2017.

In health and in disease - living together with microbes

Trillions of diverse microbes reside in our gut,  the gastrointestinal tract and as a community  collectively influence our state  of  health as well as  disease. This symbiosis  is not a recent phenomenon, says scientist Andrew Moeller who investigated the evolutionary histories of hominid gut microbiota for his doctoral thesis.  By the way microbiota  is the currently used terminology for a diverse microbial community in a given ecosystem and gut is one such ecosystem.  Acknowledging  the significant role of microbiota in human life, NIH, the National Institutes of Health, USA, initiated the ambitious Human Microbiome Project in 2008.   Microbiome is the word for the genomes of the microbial community in a given ecosystem.   Abbreviated as HMP, the project aims at, much like the earlier Human Genome Project, generating a   complete catalogue of the genomes of microbiota living in association with human body and analyse their role in human wellness and illness. 

  

Human digestive system: courtesy : wikipedia

Several very interesting pieces of information have come to light with regard to gut microbiota. Neonates beget a minimal share of maternal repertory, which gets enriched in diversity and proportion as the child grows and by  age 12 resembles the adult profile. Beyond age 70, there seems to be a decline in the  diversity and functional capabilities of the microbial community. Nature and nurture contribute to the diversity and functional capabilities  of microbiota. For example scientists suggest that the high fat high salt diet of the affluent west   and overuse of antibiotics elsewhere will leave telltale signs on the  gut microbial community Now the most important point:  the diversity and relative proportions of  microbiota is unique to each individual. In other words each of us have a unique microbial signature, a unique microbial identity.  According to experts this explains, to some extent,  individual preference / tolerance/intolerance  towards food/drug type.   

Thus by age 12 we achieve a unique balanced  microbial population in our gut.   Dysbiosis, that is  perturbations of this  balance   has been implicated in several intestinal and extra-intestinal disorders. For example in  a recent research paper Imhann et al reiterated  the role of dysbiosis  of  the gut microbiota  in inflammatory bowel disease (IBD). Others have found possible evidences to link allergy, asthma, metabolic syndrome, and even obesity. But the good news is that beneficial  microbial communities can be generated, cultivated and maintained  by consuming appropriate food. Probiotics which are fermented food items such as yoghurt, cheese, pickle etc. and prebiotics  fibre rich vegetables, fruits, cereals which ferment in the gut seem to aid this process greatly. 

TAILPIECE:
Does that mean gut feeling is just microbial biochemistry?

  

References:
1. Human intestinal Microbiome in health and disease:The New England Journal of Medicine:2016; 375:24
3. Diversity of the human intestinal microbial flora Science:2005; 10:1002-14
4. Gut microbiota composition correlates with diet and health in the elderly: Nature 2012, 488: 178-84 Claesson et al.
5.Diet rapidly and reproducibly alters the human gut microbiome: Nature 2014;505:559-63 David LA et al
6. The Gut microbiota in host health: a new clinical frontier: Gut 2016;65:330-9 Marchesi,JR et al.
7. Incorporation of therapeutically modified bacteria into gut microbiota inhibits obesity:J.Clinical Invest. :2014:124:3391-406. Chen Z et al
8. Interplay of host genetics and gut microbiota underlying the onset and clinical presentation of inflammatory bowel disease. Gut: 2018; 67: Imhan et al

When pushed to the extreme

Freezing, arid  terrain with sweeping winds: that is Antarctica, the southernmost continent on Earth.   Since the sighting of the ice mass in the first half of the nineteenth century by marine explorers,  Antarctica has attracted umpteen   expeditions. During the second half of twentieth century  extensive aerial surveys of the continent  were conducted mostly by the United States. Airplanes    carrying scientists and radar equipments criss-crossed over the icy continent. From the radar data   thickness of the ice cover  and presence of liquid water below the sheet could be estimated.   While those  old maps provide information on what the terrain was like "Then",    modern satellite imaging techniques yield detailed   "Now" images.

Antarctica with ice shelves marked-Courtesy Wikipedia

   

United States' National Science Foundation funds several projects on various aspects of Antarctica. Project Midas undertaken by UK    focuses on stability of Larson C ice shelf in West Antarctican coast. In addition to these two countries several others have  permanent research stations  there.  

Limacina Helicina Courtesy: Wikipedia

Not only penguins, blue whales and krill, Antarctica accommodates life in many other forms.  The terrain as such  is hostile; with  global warming and consequential increase in the acidity of the ocean   would it become even more inhospitable?   Tiny marine snails, Limacina Helicina (also called sea butterflies because evolution equipped them with wings rather than feet) have already devised a counter measure. Acidic ocean can leach out the protective coating on their outer shell. They have learnt to repair this damage not by regenerating the coating but by thickening the innerside of the shell by appropriate secretions. In the picture alongside, the white rectangle marks  the area where the effect of ocean acidification was studied. The antarctic fish Emerald rockcod too has braced itself against warming and acidity of the ocean, although it can take on only one at a time. 

  

Prof. Belinda Ferrari from the Australian Centre for Astrobiology recently recorded the ability of certain microbial communities to "live  on air alone".  These microbes  belonging to phyla Actinobacteria, can survive by oxidising trace amounts of atmospheric hydrogen and carbon monoxide, present in the atmosphere. Detailed genetic and biochemical studies showed that the microbes possess three very important enzymes: high-affinity hydrogenases, to  catalyse the reversible oxidation of hydrogen, carbon monoxide dehydrogenases to  facilitate the conversion of carbon monoxide to carbon dioxide and  CO2 fixation enzymes of the  RuBisCO family to   "fix" inorganic carbon into organic carbon. 

 Tailpiece:
Antarctic tourist season is from November to March, the summertime in southern hemisphere. 2016-17 clocked more than 44,000 visitors!

Blood Falls: Iron oxide stains the water flow
blood red in Taylor glacier
Courtesy:Wikipedia

References:
1. Flying lab to investigate Southern Ocean's appetite for carbon
2. Coping with climate stress in Antractica
3. Sea butterflies patch up shell damage from ocean acidification
4. Pteropods counter mechanical damage and dissolution through extensive shell repair
5. Scientists find antarctic microbes that live on air alone