Do Bacteria Have Bacteria?

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Drew Smith:

Do bacteria have bacteria? Yes.

We know that bacteria range in size from 0.2 micrometers to nearly one millimeter. That’s more than a thousand-fold difference, easily enough to accommodate a small bacterium inside a larger one.

Nothing forbids bacteria from invading other bacteria, and in biology, that which is not forbidden is inevitable.

We have at least one example: Like many mealybugs, Planococcus citri has a bacterial endosymbiont, in this case the β-proteobacterium Tremblaya princeps. And this endosymbiont in turn has the γ-proteobacterium Moranella endobia living inside it. See for yourself:

Fluorescent In-Situ Hybridization confirming that intrabacterial symbionts reside inside Tremblaya cells in (A) M. hirsutus and (B) P. marginatus mealybugs. Tremblaya cells are in green, and γ-proteobacterial symbionts are in red. (Scale bar: 10 μm.)

I don’t know of examples of free-living bacteria hosting other bacteria within them, but that reflects either my ignorance or the likelihood that we haven’t looked hard enough for them. I’m sure they are out there.

Most (not all) scientists studying the origin of eukaryotic cells believe that they are descended from Archaea.

All scientists accept that the mitochondria which live inside eukaryotic cells are descendants of invasive alpha-proteobacteria. What’s not clear is whether archeal cells became eukaryotic in nature—that is, acquired internal membranes and transport systems—before or after acquiring mitochondria. The two scenarios can be sketched out like this:

The two hypotheses on the origin of eukaryotes:

(A) Archaezoan hypothesis.

(B) Symbiotic hypothesis.

The shapes within the eukaryotic cell denote the nucleus, the endomembrane system, and the cytoskeleton. The irregular gray shape denotes a putative wall-less archaeon that could have been the host of the alpha-proteobacterial endosymbiont, whereas the oblong red shape denotes a typical archaeon with a cell wall. A: archaea; B: bacteria; E: eukaryote; LUCA: last universal common ancestor of cellular life forms; LECA: last eukaryotic common ancestor; E-arch: putative archaezoan (primitive amitochondrial eukaryote); E-mit: primitive mitochondrial eukaryote; alpha:alpha-proteobacterium, ancestor of the mitochondrion.

The Archaezoan hypothesis has been given a bit of a boost by the discovery of Lokiarcheota. This complex Archaean has genes for phagocytosis, intracellular membrane formation and intracellular transport and signaling—hallmark activities of eukaryotic cells. The Lokiarcheotan genes are clearly related to eukaryotic genes, indicating a common origin.

Bacteria-within-bacteria is not only not a crazy idea, it probably accounts for the origin of Eucarya, and thus our own species.

We don’t know how common this arrangement is—we mostly study bacteria these days by sequencing their DNA. This is great for detecting uncultivatable species (which are 99 percent of them), but doesn’t tell us whether they are free-living or are some kind of symbiont. For that, someone would have to spend a lot of time prepping environmental samples for close examination by microscopic methods, a tedious project indeed. But one well worth doing, as it may shed more light on the history of life—which is often a history of conflict turned to cooperation. That’s a story which never gets old or stale.

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Kodak’s New Cameras Don't Just Take Photos—They Also Print Them

Your Instagram account wishes it had this clout.
Your Instagram account wishes it had this clout.
Kodak

Snapping a photo and immediately sharing it on social media is definitely convenient, but there’s still something so satisfying about having the printed photo—like you’re actually holding the memory in your hands. Kodak’s new STEP cameras now offer the best of both worlds.

As its name implies, the Kodak STEP Instant Print Digital Camera, available for $70 on Amazon, lets you take a picture and print it out on that very same device. Not only do you get to skip the irksome process of uploading photos to your computer and printing them on your bulky, non-portable printer (or worse yet, having to wait for your local pharmacy to print them for you), but you never need to bother with ink cartridges or toner, either. The Kodak STEP comes with special 2-inch-by-3-inch printing paper inlaid with color crystals that bring your image to life. There’s also an adhesive layer on the back, so you can easily stick your photos to laptop covers, scrapbooks, or whatever else could use a little adornment.

There's a 10-second self-timer, so you don't have to ask strangers to take your group photos.Kodak

For those of you who want to give your photos some added flair, you might like the Kodak STEP Touch, available for $130 from Amazon. It’s similar to the regular Kodak STEP, but the LCD touch screen allows you to edit your photos before you print them; you can also shoot short videos and even share your content straight to social media.

If you want to print photos from your smartphone gallery, there's the Kodak STEP Instant Mobile Photo Printer. This portable $80 printer connects to any iOS or Android device with Bluetooth capabilities and can print whatever photos you send to it.

The Kodak STEP Instant Mobile Photo Printer connects to an app that allows you to add filters and other effects to your photos. Kodak

All three Kodak STEP devices come with some of that magical printer paper, but you can order additional refills, too—a 20-sheet set costs $8 on Amazon.

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What Is the Citizenship of a Baby Born on an International Flight?

Nadezhda1906/iStock via Getty Images
Nadezhda1906/iStock via Getty Images

It's pretty standard medical advice: a pregnant woman shouldn’t travel via airplane 36 weeks or later into her pregnancy. Despite that precaution, an occasional bundle of joy may still add an unexpected passenger to the flight manifest. As if giving birth at 40,000 feet wasn't already a stressful experience for a new mom, things can get even more hectic upon landing: Depending on the details surrounding the birth, her newborn’s citizenship could be up for debate.

There is no universal rule for how a country determines the citizenship of a newborn. Some countries just follow the jus sanguinis (right of blood) law, which means a baby’s nationality is determined by that of one or both parents. Others observe that rule and jus soli (right of the soil), where a country grants citizenship to a baby that’s simply born on its soil, regardless of the parents’ origin. These countries are mostly in the Americas and include the United States and Canada. And with the expansion of air travel, these laws had to extend to the heavens as well.

If a baby is born over United States airspace, the jus soli rule means the child would be granted U.S. citizenship, according to the Department of State Foreign Affairs Manual. Depending on the circumstances, the child may also be a candidate for dual citizenship if its parents are from a country that grants citizenship based on blood—though that would depend on the countries involved.

This same simplicity doesn’t extend to a jus sanguinis country, though. This means that an American mother can’t attain French citizenship for her baby just because she gave birth over French airspace. The baby would simply revert to the parent's U.S. citizenship, since the United States also generally follows jus sanguinis when a baby is born to U.S. citizens in a foreign country. Since jus sanguinis is the far more common rule around the globe, most babies born on a flight over international waters or foreign airspace will likely wind up taking the citizenship of its parents.

If there’s a case where the child could potentially be stateless—such as when a mother herself has no official citizenship and the baby is born in international airspace—the baby would likely take the citizenship of whatever country the plane itself is registered in, according to the United Nations’s Convention on the Reduction of Statelessness agreement.

Despite all these complex laws, mid-flight births are exceedingly rare—so rare, in fact, that most airlines don’t even keep track of the number of babies born in the air. An expecting mother likely wouldn't even be able to get onto a flight in the first place, since many airlines have rules that prohibit women from flying after they've reached a certain point in their pregnancy.

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