Sunday, May 30, 2021

Things that “Everyone Knows”


Among the things that “everyone knows” because it is just so damned obvious is that smoking impairs your sense of smell. Yet when one tabulates the studies looking at tobacco use and odor perception, the conventional wisdom crumbles more easily than the ash on a Macanudo. 

I wrote about this in What the Nose Knows, and studies since then have confirmed my skepticism: some find a link, others don’t.

A newly published “scoping review” collated the results of over 700 studies, seeking statistical associations between “social determinants of health” and olfactory function. They found some significant links (e.g., exposure to environmental and occupational toxins), but “the associations between olfactory dysfunction and education level and lifestyle factors such as smoking and drinking seem to be much more elusive.” (Translation: “we know those factors matter, we just couldn’t find convincing evidence.”)

How much more elusive was smoking as a factor? This elusive:

Of the 28 studies that examined smoking, 12 demonstrated significant positive correlation between smoking status and [olfactory dysfunction].

In other words, the majority of studies (16/28) found no link. The conventional wisdom is still batting less than .500.

The study discussed here is “Association between social determinants of health and olfactory function: a scoping review,” by Joel James, Avraham M. Tsvik, Sei Y. Chung, John Usseglio, David A. Gudis, Jonathan B. Overdevest, published in International Forum of Allergy and Rhinology published online May 28, 2021.

Friday, May 21, 2021

Amorphophallus titanum: End of the Grift?


In Alameda, California a “local gardener” invited people to an abandoned gas station and let them smell and touch his giant misshapen penis . . . plant. Nothing sketchy about this at all.

Is it just me, or has the pace of stinky “corpse flower” blossomings slowed since the pandemic? We were usually good for several such exhibitions a year at botanical gardens around the county. All that was missing were the tour t-shirts.

Perhaps specimens of giant misshapen penis plant—the literal name according to its Latin binomial, not the consumer-friendly sanitized version—all just “happened” to cease sending up their grotesque, foul-smelling inflorescences at the same time. Or perhaps their owners adjusted lighting and feeding regimes to delay the blessed events until such time as paying throngs are once again able to attend in person. Just saying.

If this cynical conjecture is correct, we should witness an epic outbreak of penis plant erections later this year. (It’ll be the biggest interdimensional crossrip since the Tunguska blast of 1909!—Ed.)

Meanwhile, in a plot twist that sounds like it was ripped from the pages of an upcoming Nick Zollicker story, the Witte Museum in San Antonio plans to fake it till they make it. That is, the museum will present a life-size model of an A. titanum blossom and allow patrons to sample a recreation of its aroma from a “smell station.” Welcome to the Audio-Animatronics® version! It’s the Disneyfication of giant misshapen penis plants.

I expect the San Antonio folks will be getting an earful any day now from the  cartel of botanical garden directors.

Tuesday, May 11, 2021

A Gloomy Day on Social Media


It snowed a couple of inches yesterday across the Front Range of the Rockies and this morning the lilacs and the aspen saplings at FirstNerve Manor were bent under the icy weight. It’s been dark, overcast, and raining all day long. One stares out the window waiting for something better to happen. Then, just when one begins to reorganize the pencil drawer comes a flash of insight—what a perfect afternoon to weed out the LinkedIn connections!

Some calls are easy—those people you interacted with years ago but whose careers have gone off in entirely different directions from your own. It’s unlikely you will ever have a professional interest in common with them again. So—“Remove Connection.”

Then there are the connections that bring you up short—the old friend who died unexpectedly nearly a year ago. It seems callous to delete the link, but even a candle lit in his memory would eventually burn out. (“Remove Connection.”) Then the likeable guy you pitched some business with before he dropped dead after a squash game a decade ago. You went to his funeral and memorialized him here. Does a persistent online link express anything further? (“Remove Connection.”) Ditto the former client’s late husband who you liked and respected.

Even more depressing is to find the connections who, once in senior positions, are now retired. One thinks, uncharitably, that they are now just taking up virtual space in your LinkedIn connections. (“Remove Connection,” “Remove Connection,” etc.)

The same goes for academics who have levitated themselves into “emeritus” status. (“Remove Connection.”) And then, a long-ignored discontent bubbles up—why link to any academics at all? Professors are easily found via their campus web pages. Basta. (Three more “Remove Connections.”)

The late afternoon sun has broken through and the birds are singing once again. The virtual thicket has been thinned out and is ready to welcome new tendrils of professional linkage. Time for a drink.

Saturday, May 8, 2021

Yeah, About That TPS Report Cover Sheet . . .


Unlike ex-Initech employee Peter Gibbons, I’m a fan of TPS reports. That is to say, studies of terpene synthases (TPS) in cannabis. These are the plant enzymes that turn precursor molecules into the various fragrant terpenes behind each strain’s aroma profile. Some TPS enzymes convert geranyl diphosphate into a slew of monoterpenes, while others convert farnesyl diphosphate to a bunch of sesquiterpenes.

Identification of cannabis terpene synthases and the genes that produce them is a relatively new field. Canadian researchers led by Judith K. Booth at UBC in Vancouver were early leaders in this effort and last fall they published another study. This one, in Plant Physiology, was the subject of a “news and views” piece in the same issue, written by Marc-Sven Roell at the Heinrich-Heine University in Düsseldorf.

Like Bill Lumbergh, I have some issues with Roell’s TPS report cover sheet. Specifically, with his claims about what is required for future cannabis breeding efforts aimed at fragrance and flavor.

To predict and design cannabis smell and taste to meet consumer demands, two milestones have to be reached. First, a comprehensive understanding of terpene composition is required, which can be achieved by using quantitative terpene profiling in existing cultivars. Second the underlying molecular and biochemical mechanisms leading to these distinct profiles need to be understood.

Roell insists that we must first know everything about terpenes in all cultivars—their complete chemical composition plus their physiological means of production—before we can get around to breeding hybrids with specific consumer appeal.

Notice anything missing? How about sensory evaluation of the smell and taste of the existing cultivars? And how about relating perceived aroma to differences in terpene composition?

Roell no doubt expects to find cultivar to cultivar differences in terpene composition, which he assumes will equate to differences in aroma and flavor. But differences in chemical composition don’t necessarily translate into perceptible differences in aroma, much less differences that are meaningful to cannabis consumers. So his strategy of starting with comprehensive knowledge of terpene composition will be enormously inefficient.

This objection also cuts in the opposite direction. As a plant physiologist, Roell ought to know that even within genetically identical clones, terpene composition can vary with growing conditions. Thus, it is possible that within-clone variation could result in perceptible aroma differences.

So either way you look at it, Roell’s insistence that baseline chemical data is an absolute prerequisite for breeding better smelling cannabis is pretty weak, especially when he totally neglects sensory measurement.

In fact, I’d argue that the best way to assist breeding efforts is begin with quantitative sensory evaluation of a range of existing cultivars. Next, cross-tabulate aroma profiles with sales and consumer preference data to obtain a ranking of most-valued sensory traits. Go back to your list of cultivars and start hybridizing for likely winners. It’s the purely phenotypic selection method that worked very well for Luther Burbank in the days before gene sequencing and gas chromatography. This approach would get the program going a lot faster than Roell’s “study the hell out of everything before making a move” strategy. I think he has it totally backwards—sensory analysis should precede chemical analysis.

“Hello Marc-Sven, what’s happening?

We have sort of a problem here. Yeah, you apparently didn’t include sensory analysis in your new cover sheet on the TPS report.

Did you see the memo about this?

Yeah, if you could just go ahead and make sure you do that from now on that would be great. 

And I’ll go ahead and make sure you get another copy of that memo.”

The study discussed here is “Terpenes in Cannabis: Solving the puzzle of how to predict taste and smell,” by Marc-Sven Roell, published in Plant Physiology 184:8-9, 2020.