Saturday, September 2, 2017

Hodgepodge 308/365 - Nightshade

This evening I finally got to meet a Flickr friend, Rachel, and her husband, Bob. They're in town for a meeting, and suggested we get together for dinner. And so we did, at our favorite restaurant, Passionfish, which was a hit. We chatted up a storm and had a lovely time. Even though I've "known" Rachel for probably ten years, it was mainly through our shared enthusiasm for photography. Tonight we got to fill in some stories and background. There was a surprising number of parallels in our trajectories. It was great getting to know them.

Bob can't eat gluten, so he asked what on the menu would be off limits. The server responded with a sheet outlining all the food allergies with respect to this week's menu: among the offenders, gluten, dairy, nuts, shellfish, and nightshade.

Nightshade reminded me of our friend Tom, who went through a diet regimen to determine what foods he is allergic to. Wheat came up, and dairy, but surprisingly, nightshade is an even worse choice for him: it gives him serious, debilitating headaches.

Illustration of Solanum dulcamara,
1.- Flower, 2.- Flower in longitudinal
section, without the petals;
3.- Androecium; 4.- Ovary, in
transverse section; 5.- Seed viewed
from above; 6.- Seed in transverse
section, note the curved embryo
surrounding the endosperm; A.- Branch
with leaves and flowers; B.- Stem
with immature and mature fruit
Nightshade, or the Solanaceae family, "ranges from annual and perennial herbs to vines, lianas, epiphytes, shrubs, and trees, and includes a number of important agricultural crops, medicinal plants, spices, weeds, and ornamentals. Many members of the family contain potent alkaloids, and some are highly toxic, but many, including tomatoes, potatoes, eggplant, bell/chili peppers, and tobacco are widely used" (Wikipedia). Tobacco! I had no idea. Petunias are also in the nightshade family.

Solanaceae comprises 98 genera and some 2,700 species (1,500–2,000 in Solanum alone, the genus that contains potatoes, tomatoes, and eggplant). It is present on all the continents except Antarctica, with the greatest diversity in South and Central America.

You say tomato . . .
Many of the species in this family are used for research into fundamental biological questions. Since 2003, for example, an international project bringing together scientists from fifteen nations has been seeking to understand how the same collection of genes and proteins can give rise to a group of organisms that are so morphologically and ecologically different. The project began with the sequencing of the tomato's genome.

Georgia O'Keeffe, Jimson Weed (1937)
The reason nightshades are on the Do Not Eat list for many people is the presence of various alkaloids: solanine, tropanes, nicotine, and capsaicin (the "hot" in a chili pepper). These compounds help protect the plant from herbivores and insects. Humans have used them as poisons, but they also have important pharmacological functions: think scopolamine patches for seasickness, atropine used to dilate the pupils during an eye exam or decrease saliva production during surgery, hyoscyamine to treat peptic ulcers. My friend Tom is probably highly sensitive to solanine, which has various symptoms if ingested in great quantities—gastrointestinal and neurological disorders, including stomach upset, hallucinations, and headaches. That said, shamans use datura (jimson weed) and mandrake precisely because of these toxins: hallucinations are what they want.

Me, I'm glad I can eat nightshades. I love pasta Bolognese, baingan bharta (Indian eggplant), chiles rellenos, scalloped potatoes. Or just plain ol' chips with salsa or baba ganoush. I'm not picky. And more to the point, not allergic. Thank goodness.

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