Headline Party

My first master's degree was in architecture, and I graduated the day the United States housing market collapsed. So my second master's was in public health, and I got my first job the day Planet Earth went into pandemic lockdown. Expertise in indoor air quality and occupant exposure during an airborne pandemic will make your life pretty busy. Hence, a list of smell-related headlines I've been collecting in the meantime:

Unparalleled inventory of the human gut ecosystem

Jul 2020, phys.org

https://phys.org/news/2020-07-unparalleled-human-gut-ecosystem.html

The Unified Human Gastrointestinal Genome (UHGG) collection, comprising 204,938 nonredundant genomes from 4,644 gut prokaryotes. These genomes encode >170 million protein sequences, which we collated in the Unified Human Gastrointestinal Protein (UHGP) catalog. 

via the European Bioinformatics Institute: Alexandre Almeida et al. A unified catalog of 204,938 reference genomes from the human gut microbiome, Nature Biotechnology (2020). DOI: 10.1038/s41587-020-0603-3

Fresh sea spray turns 'sour' after being airborne

Jan 2021, phys.org

https://phys.org/news/2021-01-fresh-sea-sour-airborne.html

"The smallest particles become 100,000 times more acidic than the ocean within two minutes," said Angle, first author of the paper.

via University of California San Diego: Kyle J. Angle et al. Acidity across the interface from the ocean surface to sea spray aerosol, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.2018397118

Researchers create a highly sensitive biohybrid olfactory sensor

Jan 2021, phys.org

https://techxplore.com/news/2021-01-highly-sensitive-biohybrid-olfactory-sensor.html

So we decided to combine existing biological sensors directly with artificial systems to create highly sensitive volatile organic compound (VOC) sensors. We call these biohybrid sensors."

Takeuchi and his team essentially grafted a set of olfactory receptors from an insect into a device that feeds certain odors to the receptors and also reads how the receptors respond to these odors. 

via the University of Tokyo: T. Yamada el al. Highly sensitive VOC detectors using insect olfactory receptors reconstituted into lipid bilayers. Science Advances (2021). DOI: 10.1126/sciadv.abd2013

Male butterflies mark their mates with repulsive smell during sex to 'turn off' other suitors

Jan 2021, phys.org

https://phys.org/news/2021-01-male-butterflies-repulsive-sex-suitors.html

Butterfly genitals secrete an odor that covers female genitals, deterring other males from mating with them. Occimene - it's the anti-aphrodisiac (for moths).

via University of Cambridge: Darragh K, Orteu A, Black D, Byers KJRP, Szczerbowski D, Warren IA, et al. (2021) A novel terpene synthase controls differences in anti-aphrodisiac pheromone production between closely related Heliconius butterflies. PLoS Biol 19(1): e3001022. 

Cosmic mouthful - Tasters savor fine wine that orbited Earth

Mar 2021, phys.org

https://phys.org/news/2021-03-cosmic-mouthful-tasters-savor-fine.html

This comes via the Institute for Wine and Vine Research in Bordeaux, and of course the International Space Station.

Researchers develop new smell test for Parkinson's, Alzheimer's and COVID-19

May 2021, phys.org

https://medicalxpress.com/news/2021-04-parkinson-alzheimer-covid-.html

A new smell test developed by Queen Mary University of London researchers has been found to be easy to use in patients with Parkinson's disease, and could also be helpful in diagnosing COVID-19 in the broader population.

via  Queen Mary, University of London: A. Said Ismail et al. A novel capsule-based smell test fabricated via coaxial dripping, Journal of The Royal Society Interface (2021). DOI: 10.1098/rsif.2021.0039

Scientists invent an artificial nose for continuous bacterial monitoring

Jun 2021, phys.org

https://phys.org/news/2021-06-scientists-artificial-nose-bacterial.html

via Americans for Ben-Gurion University: Nitzan Shauloff et al, Sniffing Bacteria with a Carbon-Dot Artificial Nose, Nano-Micro Letters (2021). DOI: 10.1007/s40820-021-00610-w

Gaia Bots and Plant Pots

It was long before artificial turf and breast implants that humans began losing their connection with nature.

There is a long history of our love affair with Mother Earth, and two variations on this theme for those interested in the subject could be the American Frontier and the English Garden (both circa 1700-1800's). In the former, the West was a force to be feared, explored, and eventually dominated. In the latter, the Garden was a symbol of the picturesque, idyllic and meandering qualities of nature, albeit designed and maintained by human intervention.

The picture-perfect English Garden isn't much different from pretty much anywhere else on Earth – it's all a hybrid. Everything on this planet has in some way been shaped by us. You want evidence? How about the serious debate by geologists trying to demarcate the beginning of the Anthropocene as a geologic epoch. We've been terraforming this place since the dawn of agriculture and have no plans on stopping (carbon dioxide be damned).

This is quite a lofty intro for a post about houseplants. But this is where we start because the myth that "houseplants filter indoor air" is tenacious. It's also a great example of what makes a meme sticky, because it's simple, easy to understand, and common to everyone. It's also wrong.

You can't blame us. We want the outside inside; we're all biophiles! We want it to be true that filling our house with plants will enhance our indoor environment in scientifically-supported, quantifiable ways.

But it's fake news. And in the manner of all news that is fake, the idea that houseplants clean our indoor air is not absolutely wrong. They do clean the air, just not enough to make a difference.

I mean, if you were on a spaceship, where ev-er-y-thing makes a difference, then sure. That's where this all started. Studies done for NASA showed that they could use plants as part of a larger air-cleaning strategy. And there you have it, memetic gold.

(You know what's not mememtically robust? The fact that it's the soil microbes doing all the dirty work, not the plants themselves!)

The bottom line is that the amount of clean, fresh air that can be delivered by a typical mechanical exhaust ventilation system is a few magnitudes more than that coming from our vegetal ancestors. Or, if you really insist on bringing the outside in, open a window.

-image source link

Post Script

We start domesticating plants 10,000 years ago as a part of the Neolithic or Agricultural revolution. The ancients of Egypt, India, China, Greece and Rome all put plants in pots, but most of these were used to decorate outdoor spaces (think Hanging Gardens of Babylon). We can trace the practice of using houseplants back to the 1600's with a book called The Garden of Eden. But Buckminster Fuller's 1967 Biosphere might have a lot more to do with their current ubiquity.

Post Post Script

Our indoor space as urban dwellers is vastly different than that of jungle huts. Obviously. But what you may not have known is that our walls and windows trap so much of our own metabolic excreta that we live in higher concentrations of our own filth than someone in a thatched hut.

You can’t really measure “filth” in this context, so the above statement is more hyperbole than fact. However, this collaboration between the Microbiology and Anthropology Departments at Rutgers University, New Jersey, painted a good comparative picture of our respective indoor environments.

They studied a remote Peruvian jungle village of thatched huts with no walls, a Peruvian rural town with wooden houses sans indoor plumbing, a Peruvian city of 400,000 residents, and the two million-strong metropolis of Manaus, Brazil.

They found that we have a higher diversity of chemicals from medications and cleaning products and of fungi associated with human skin, the mouth and the gut, whereas the rural and jungle homes had a greater variety of outdoor-associated bacteria and fungi typically found in water and soil.

This is because the walls themselves trap all this stuff as it floats in the indoor air. We also have warmer, wetter air than a jungle hut, as well as less sunlight and less fresh-air exchange. This plus the tons of dead skin cells we leave lying around all make a great incubation-chamber for fungi. So despite the fact that urban dwellers clean more frequently, their indoor environment is teeming with micro-organisms that live in and on our bodies.

The end result is that our homes, in the more urban areas, and in more modern times, are more like the human body than the body of Mother Earth.

Home chemical and microbial transitions across urbanization, Nature Microbiology (2019).

DOI: 10.1038/s41564-019-0593-4 

https://nature.com/articles/s41564-019-0593-4

Walls talk: Microbial biogeography of homes spanning urbanization, Science Advances

advances.sciencemag.org/content/2/2/e1501061

Notes

Actually, potted plants don't improve indoor air quality

Nov 2019, phys.org

Foliage plants for improving indoor air quality

1988, NASA and BC Wolverton.

The Potted-Plant Microcosm Substantially Reduces Indoor Air VOC Pollution

RL Orwell, RA Wood, MD Burchett, J Tarran, F Torpy.

Water, Air, and Soil Pollution. 177 (1–4): 59–80. 19 September 2006.

doi:10.1007/s11270-006-9092-3.

American Frontier

English Garden

Houseplants

**Buy Sir Hugh Platt's original 1675 book Garden of Eden, here for $3,500

The Acid Test

Cooking with Dice: The Acid Test

Just when you thought a role playing game fortified with immersive scent-explorations was 'out-there' as far as gaming goes, the creator of Adventure Scents have now come up with a new idea, even more multimodal than their last.

This time we're looking at Cooking with Dice: The Acid Test, a ‘classic RPG with a delicious twist,’ and in other words, a Gamified Cookbook.

What the hell is a gamified cookbook? It’s half cookbook, half role playing game. The Cooking with Dice system uses elements of traditional tabletop role-playing games to turn your kitchen into an adventure zone

Your character tries to level up to the esteemed Chef de Cuisine by executing recipes concocted by a roll of the dice. What's interesting here is that the recipes don't use heat, but acid (like the chemical-reaction-acid, not the kind of acid that melts your face off). You make things like pickles, jam, ceviche, .... No fire-breathing dragons necessary.

If this is anything like the last offer from Jennifer Howlett, Adventure Scents creator and game guru extraordinaire, Cooking with Dice is guaranteed to be an adventure of multisensory complexities.

POST SCRIPT

I can’t help but zero-in on the way this game is ultimately played, which is by fostering chemical reactions that turn raw ingredients into edible adventures. First of all, it’s genius for a kids’ cookbook – they get to “cook” and yet they don’t even have to play with fire.

Next of all, it totally reminds me of The Art of Fermentation by Sandor Katz, which won the 2013 James Beard Foundation Book Award for Reference and Scholarship, which pretty much blew my mind when I read it. If you think you know what it means to be human and yet you haven’t read it, maybe you should. The idea of offloading the work of digestion to bacteria that exist outside our bodies, so that our bodies can do more important things – like thinking – is nuts. (It also helps to put in perspective the development of cooking and human digestion – where fermentation is the accelerating of a metabolic process via bacteria, cooking is the same but by fire. One is a kind of biological heat, and the other a more basic, chemical heat.) Anyway, fermentation is cool, and I think Jennifer Howlett is one smart cookie for coming up with this workaround for a kids’ (gamified) cookbook.

Finally, the ‘acid test,’ as she calls it, is essential to understanding the world of smell, because smell is a bacterial thing, a microbial thing. You cannot smell chlorine, or ammonia, or sulfur (these are single chemicals and we can’t smell that kind of thing). What you smell are biological reactions involving these chemicals, and which have created through their reactions more complex organic molecules that we can smell. Metal does not smell; “the smell of metal” is bacteria that live on our hands and in our sweat, reacting with metal to create new compounds that smell “like metal.” Understanding acids and how they work is the foundation for chemistry, and this gamified cookbook is a synaesthetically satisfying way of getting to know chemistry and the smells that come from it.

Check it out!

And while you’re at it, if you’re ever looking for that perfect ‘moldy dungeon’ smell or the smell of the breath of a fire-breathing dragon, check out Adventure Scents.

Bacteria, Molecules, and Other Small Things That Sense and Remember

 

Image Source

Here I’ve compiled some articles from my notebook that look at how our senses work when it comes to simpler forms of life, like bacteria. There’s even something about how molecules – very far from what we consider ‘living things’ – uses a form of memory. All this has been put together to reinforce an idea presented in Hidden Scents which suggests that our awe-inspiring brain is similar to things less inspiring, like the lowly eukaryote.

Some of these things are really old, and most of the text here is copied from the links provided. Overall I hope it’s interesting enough to keep your attention:

***

Bacteria can 'smell' their environment, research shows
BBC, Aug 2010

“…there is a distinction between an organism reacting to a chemical that it encounters directly (in analogy to the sense of taste) and a reaction to a chemical that is floating around in the air, says Reindert Nijland, lead author of the study.

"The compounds detected by olfactory organs are generally much more volatile than things you can taste like 'sweet' or 'salt', and therefore can provide information about things that can be much further away; you can smell a barbecue from a few blocks away whereas you have to physically touch and eat the steak to be able to actually taste it."

***

Urbanization leads to change in type of bacteria in the home

phys.org, Feb 2016

“ "Very little is known about the microbes of the built environment," microbiologist Maria Gloria Dominguez-Bello of New York University, who led the pilot study, said at a meeting of the American Association for the Advancement of Science.

…

“Her team found that as people living in the Amazon rainforest become more urbanized, the kinds of bacteria in their homes change from the bugs mostly found in nature to those that typically live on people, she reported Friday.

In fact, in city dwellings, the researchers could tell just by the microbial fingerprints of the walls that "this is a kitchen or this is a bathroom or this is a living room. That's amazing," Dominguez-Bello said.

“Despite fewer occupants, the more urbanized a dwelling, the more human bacteria lived on its walls and floors, the researchers reported in the journal Science Advances. In Manaus, a collection of microbes normally found in the mouth, including various species of strep bacteria, and in the gut were the most important in telling rooms apart. The more crowded jungle and rural homes nonetheless were filled with more bacteria commonly found in soil and water than with human microbes.”

The microbiome has become a big deal lately. As much as it is invisible, it’s not unrecognizable.

Its kind of funny how, first, we didn’t know what microorganisms were one hundred years ago, and are only now beginning to understand the role of microbes (in their totality, as the microbiome) in human health, and yet, I would conjecture that the smell of the microbiome, its dynamic states of existence and effects, have been well known to us for quite some time. I cannot see your body odor, even if I look really close. But I know it’s there.

 

Intelligent Flagellum

***

'Molecular memory' of light exposure helps plants to remember daylight during winter nights

phys.org, Feb 2016

This isn’t about smelling, but sensing nonetheless…

“Dmitri A. Nusinow, Ph.D., assistant member at the Danforth Plant Science Center and researchers in his lab studying plants' circadian clock have discovered a gene that allows plants to remember daylight during the long nights of winter, helping them tailor their growth appropriately to the seasons.”

***

Bacteria 'see' like tiny eyeballs

BBC, Feb 2016

“After more than three centuries of scientists eyeballing bugs under microscopes, Prof Mullineaux said it was remarkable that nobody had picked up on this before.”

“the entire organism acts like an eyeball”

“Cyanobacteria, including the Synechocystis species used in the study, are an ancient and abundant lifeform. They live in water and get their energy from photosynthesis - which explains their enthusiasm for bright light.”

Can’t resist mentioning that cyanobacteria are what make the ‘smell of the seashore;’ it emanates from their little bacteria bodies as they metabolize, and we can also call it seaweed sweat or seaweed pheromones or seaweed seeking sex.

***

Let them see you sweat: What new wearable sensors can reveal from perspiration

phys.org, Jan 2016

“This device, reported in the Jan. 28 issue of the journal Nature, is the first fully integrated electronic system that can provide continuous, non-invasive monitoring of multiple biochemicals in sweat.

“The advance opens doors to wearable devices that alert users to health problems such as fatigue, dehydration and dangerously high body temperatures.

"Human sweat contains physiologically rich information, thus making it an attractive body fluid for non-invasive wearable sensors."

***

[and on that note...]

Antiperspirant alters the microbial ecosystem on your skin

phys.org, Feb 2016

"Thousands of bacteria species have the potential to live on human skin, and in particular in the armpit," says Rob Dunn, a professor of applied ecology at NC State and co-author of the paper. "Just which of these species live in any particular armpit has been hard to predict until now, but we've discovered that one of the biggest determinants of the bacteria in your armpits is your use of deodorant and/or antiperspirant."

…

"We found that, on the first day, people using antiperspirant had fewer microbes in their samples than people who didn't use product at all - but there was a lot of variability, making it hard to draw firm conclusions," Horvath says. "In addition, people who used deodorant actually often had more microbes - on average - than those who didn't use product."

“By the third day, participants who had used antiperspirant were beginning to see more microbial growth. And by day six, the amount of bacteria for all study participants was fairly comparable.

"However, once all participants began using antiperspirant on days seven and eight, we found very few microbes on any of the participants, verifying that these products dramatically reduce microbial growth," Horvath notes.

“The participants who had been regular antiperspirant users coming into the study had wildly different results. Sixty percent of their microbes were Staphylococcaceae, only 14 percent were Corynebacteria, and more than 20 percent were filed under "other" - meaning they were a grab-bag of opportunistic bacteria.

***

[aaaandddd]

Computer scientists achieve breakthrough in pheromone-based swarm communications in robots

phys.org, Nov 2015

“Swarm robotics is an emerging approach to the coordination of multi-robot systems, which takes inspiration from the natural world to examine the possibilities for improved interaction between robots and their surrounding environment.

“Until now, researchers specialising in swarm robotic applications have been unable to replicate all the aspects of pheromone communication that occur in the natural world.

…

“Specialists from the University of Lincoln's School of Computer Science have now produced a novel artificial pheromone system that is reliable, accurate and only uses 'off-the-shelf' components …[which] allows users to simulate several pheromones and to change their strength.

“Led by Farshad Arvin, PhD researcher in the School of Computer Science, the Lincoln team developed the system using their own Colias platform. They created Colias - an open-platform system that can be used to investigate collective behaviours and be applied to swarm applications - in 2014 in collaboration with experts from Tsinghua University in China.”