On origin of life: Packman goes forth

The line between life and non-life is becoming increasingly blurred.  We use biological molecules as molecular machines and even as a base of computing. On the other side of the spectrum, inorganic materials are constructed to display a cell-like behaviour.

But there’s a gap between these organisation levels and the most primitive living cells capable of matter and energy exchange with the environment (metabolism) and reproduction. Experiments that bridge the gap between complex inorganic and a living cell brings us closer to understanding how life came to be.

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Two consequent of optical microscopy images showing spontaneous transfer of silica colloidosome (red object, dotted line) into a magnetic droplet through a fatty acid stabilized aperture. Scale bar = 100 µm. (Image by University of Bristol).

Magnetite + organic solvent =

The authors of a recent article in Nature materials (Rodrigues-Arco et al. (2017), DOI: 10.1038/NMAT 4916) tried to bridge the gap between inorganic and organic. They mixed magnetic particles of iron oxide (magnetite) with droplets of an organic solvent and water. The particles with diameter of 500 ± 250 µm self-assembled on the surface of the solvent and were stable for several weeks.

Applying a magnetic field to the magnetic droplets opened the spheres along the surface, but they didn’t lose structural integrity and returned to the spherical shape. 

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Magnetite droplets open and close on   magnetic field application (Image by  Fr4zer  via Wikimedia Commons)

Increasing pH of the water phase to 10.5 and oleate concentration led to the creation of Matryoshka structures: parts of droplets remained covered by magnetic nanoparticles, and the rest of the structure was bordered by a monolayer of organic molecules.  At an optimal concentration, 3/4 magnetite with 1/4 water surface droplets resembled the hero of the classic game, Packman in appearance and behaviour.

 

Adding silica 

Under the same conditions, silica particles form smaller spheres, 50 ± 20 µm in diameter.  Silica colloids mixed with magnetic spheres do not interact in the absence of oleic acid. However, applying a magnetic field to the mix opened apertures in the magnetic spheres led to their self-propelled movement and random engulfment of colloidosomes. Only spheres with apertures – Packmen –  were able to move. The authors call this the engulfment ‘phagocytic-like behavior’ after ameba-like white blood cells that eat bacteria.

Particles movement explained by Marangoni effect – a movement due to surface tension gradient because of the uneven distribution of oleate on the surface of magnetic particles.  As the oleate gradient dissipate, the droplets moved only for several seconds. 

The authors proposed a model of ‘phagocytosis’. Non-magnetite covered surface Packman aperture covered by oleic acid molecules acts as a single layer proto-membrane. The silica colloidosomes have this layer as well. Fusion of molecular layers on the surface of Packmen aquatic opening and release of colloidosomes into the inner space creates semi-double membrane particles.

See the pictures and models on Nature web-site.   If by some miracle you have access to the original paper, do look into the supplemental videos of Packmen moving, Packmen ‘eating’, it’s mesmerising.

What is it good for

The authors propose using composite droplets mixtures for development of new material and nanoscale engineering approach, for example in microfluidics and delivering reagents for spatially controlled reactions. This sounds plausible and the author’s intention to mimic predation and chemical communication even more interesting.

However,  the scientists also call droplets ‘protocells’ and talk about ‘populations’ and their ‘collective behaviour’. In my opinion, this is a bridge too far. Life is characterised by sustained metabolism and ability of self-propagation. Magnetite and silica droplets display neither.  The reports about creating synthetic life is overhyping, the chronic disease of modern science.

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Laser in a droplet

 

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      A typical laser – Terminator rules. (Image by US Air Force, via Wikimedia Commons)

When you hear about a laser, you imagine a medium-size apparatus with a light beam coming out of it. You don’t imagine bacteria in a drop of liquid. Well, Turkish and British scientists went beyond ordinary imagination and published their findings in Lab on Chip

 

If you don’t own a laser in a form of a laser pointer, you certainly use one when you scan your purchases. To construct a laser, you need three things – a source of energy to get it going, a material capable of amplifying it and a feedback mechanism allowing to amplify the initial energy even more.

In a run of the mill lasers, the initial electromagnetic waves are trapped by mirrors, which bounce and enhance them. One of the mirrors is semi-transparent, allowing some of the amplified energy to escape. If the escape is a narrow slit and the energy in the visible light part of the spectrum, it creates a laser beam, the weapon of choice of SF battles.

(A nice  animation of laser)

In a typical laser, you have a gas-filled cylinder or a glass rod with ions for the energy amplification. However, the internal paraphernalia can be replaced by an illuminated liquid droplet suspended in mid-air via a standing sonic wave (Whovians, rejoice!) or optical tweezers.

 

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A suspended water droplet – unlikely laser. (Image by Thomas Bresson [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)%5D, via Wikimedia Commons

A  suspended droplet is a perfect sphere, which allows the initial light to go inside and bounce from the internal edges of the sphere. A photon from an excitation laser can make tens of thousands of bounces.  The liquid inside the drop serves as the amplification medium and the droplet edge as mirrors.

 

Some of the light leak from the droplet-cavity in all directions. Because the leakage is omnidirectional, there is no beam, but the droplets size – from nano to micrometers – and variable droplet composition allow using the droplet lasers for various applications.

 

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Bacteria expressing differently coloured fluorescent proteins glow in the dark.  (Image  by Nathan Shaner [GFDL  or CC-BY-SA-3.0 ] via Wikimedia Commons)

Once you’ve done your initial setup of an external light source and supply of droplets, you can vary the droplet composition. You can put in fluorescent dyes for a signal amplification.  Or you can use a fluorescent protein, which emits light.

 

The Turkish scientists went further and instead of a purified protein, used a live E.coli cell, which synthesized a fluorescent protein. One bacterium containing lots of fluorescent molecules was enough to create a tiny laser.

 

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Bacteria E.coli seen via tunneling electron microscope – even unlikelier laser.  (Image by    NIAID [CC BY 2.0] via Wikimedia Commons)

The droplet-based lasers, containing biomolecules and even live cells can be used in biosensors, environmental analysis and lab-on-chip.

 

6+ animals that defy laws of nature

 

1. Walking fish

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Shuttles hopfish and its son (Image by Alpsdake/Wikimedia Commons)

Remember that  Guinness ad where the evolution goes back: men devolve into cavemen, birds into dinosaurs? It ends with two little fish walking to water and expressing disgust at its taste. These fish do exist. The fish from the advert is close to mudskipper – an Australian fish.

2. Living on land fish

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Nutricosmetics: snake oil now in a pill form

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Nutricosmetics: ingest before breakfast, repeat twice during the day. Pay $60+ per month.  (Image by Iryna Ilkavets, Samsung Galaxy Note 2, CC-BY)

In The Stylist beauty issue, there is a feature article about nutricosmetics, defined as “beauty products you ingest rather than apply”. The rationale – skin/hair/nail are growing things, which you can supplement from outside (the usual “beauty products” – lotions and creams) or from an inside  – in a pill form. Sort of spray on the leaves fertiliser vs. fertiliser in the soil for your plants.

Sounds good if you don’t pay attention to the caveats mentioned in the article:

A)  As the skin is outside of the body, whatever product you are eating, you need to saturate the body from within to get to the skin.

B) The air conditioner argument. Your body is like an air conditioner – when it overshoots the set temperature, it compensates by cooling, sometimes overshooting in the other direction but eventually returning to the balance. So if you try to increase the concentration of say, vitamin A by eating a lot of it in one go, after a short spike the excess is removed via urine, and there is an actual drop in its concentration. And if it accumulates, you skin turns orange and it becomes toxic.

Let’s have a look at the products mentioned in the article about nutricosmetics:

Lumity – £90 ($135) per month for a cocktail of lysine, arginine, and glutamine. These are aminoacids,  building blocks of protein. I don’t have a problem with this, except that you should be getting enough aminoacids from you food. And if you want to top up just in case, you can buy aminoacids in any health shop for 1/10 of the Lumity  price. Continue reading

Why do we bury our dead: transmissible Alzheimer’s revisited

A protein molecule is like an origami: it folds and folds in mysterious ways until you have a 3D structure. But beware of incorrect folding, it gives your aggregation and diseases . Image by OpenStax College [CC BY 3.0 ], via Wikimedia Commons

In my earlier post, I wrote about a finding that transfusion of a contaminated protein, growth hormone, led to the patients developing “mad cow disease” (CJD) but – more unexpectedly – Alzheimer’s disease.

The good news is that the finding, as it often happens with much-publicized results, is not a fluke. It’s been confirmed by an independent study. The bad news  – there’s a new way of Alzheimer’s disease transmission in town.

The Swiss scientists studied people who were transplanted tissue that covers the brain and spinal cord, called dura. Seven of dura recipients died from CJD. Their brains were studied postmortem – the only way to diagnose CJD – and five of them had signs of Alzheimer’s. The patients were too young to acquire this disease of old age.

This finding can be confirmed by a third independent group in Japan, although it’s as  yet unpublished.

There’s need to panic. Just as HIV is not transmitted by touch and cuddle and kiss, short of injecting or transplanting the diseased matter, there is no way you will be infected by interaction with an Alzheimer’s patient. The doctors do not use hormones or dura purified from cadavers anymore. They were replaced by synthetic replacements, which don’t have diseases seeds.

On the other hand, surgical procedures are not designed with CJD and Alzheimer’s ‘seeds’ in mind. The seeds are very resistant to the usual sterilisation treatments, which kill bacteria and viruses. They are just incorrectly folded protein and don’t need DNA for reproduction. With the number of old patients who have more chance of having Alzheimer’s rising the chances of seeds, transmission raises as well, unless the doctors do something about it.

Men’s Skincare: The Unusual Suspects

A stinging nettle plant. Image By Júlio Reis (Own work) [CC BY-SA 3.0], via Wikimedia Commons

Men have it easy if you consider the volume and degree of bullcrap associated with products targeted to women. Maybe the marketers think that men are less inclined to believe bull or they are more critical or more scientifically minded. Or afraid to scare off men, who for centuries survived without skin products beyond hair grooming. But as the number of men’s grooming products increases to include eye creams and moisturisers the bullshitters are moving into the new territory.

Take the Autumn/Winter Style Issue of  British  ShortList magazine. One its features were about men’s grooming products, which contain unusual ingredients.  Some of the ingredients don’t raise my eyebrow – I know about the vast spectrum of biologically active compounds, which plants accumulate. I would never argue that, for example,  Camomile extract does not soothe skin irritation, or that tea tree oil inhibits blemishes.

But let’s have a look at the list, assuming that the title ingredients are not present in “homoeopathic”  e.g. “name only, no substance” quantities.

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Dissecting skincare, Part II – the strangest of the rest

Following my previous post about  one of the winners of Stylist’s best skincare products awards.

Best body lotion

Dove purely Pampering Nourishing Lotion

..this is packed with nourishing shea butter and collagen amino acids to improve skin elasticity.

 

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A model of a collagen molecule. Good looking but too big to get into your skin cells.  Image  By Nevit Dilmen CC-BY_SA 3.0 via Wikimedia Commons 

As I’ve written my previous post, collagen is the protein that provides skin elasticity. The previous generation of potions contained collagen with exactly the same claim as applied now to its amino acids.

So why the shift from the collagen to its amino acids? Maybe the common/scientific sense that collagen’s molecule is too big to filter down through the skin and – even if it gets inside the skin cells – they’ll break protein  down to its building blocks, amino acids, won.

But more likely,  a never ending cycle of producing, whipping up the interest and selling new (= better) products required  new entities. Amino acids from collagen sounded like a valid idea. Amino acids are small molecules and can be taken up by skin cells. Except that there no guarantee that they will be used to make specifically collagen and not randomly incorporated into whatever proteins cells synthesizing right now.

Slathering skin with amino acids from collagen is like giving an average adult some money and expecting that he’ll spend it on fruits and vegetables and not on burgers and alcohol.

Best exfoliator

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