And what are the reasons?

Hello, Reddit!

We are members of Iverson Lab at Vanderbilt University, Dr. Tina Iverson and Prash Singh. We study the connection between metabolism and cell fate when organisms respond to their environments. One of our projects seeks to understand how bacteria use a nano-motor to move in response to environmental conditions. This is important because these nano-motors allow bacteria to move towards energy-rich environments for survival and hide from antibiotics during infections. Globally, bacterial infections account for 1 in 8 deaths each year. Currently, antibiotics are our best defense; however, due to factors such as antibiotic misuse/overuse, genetic mutations, and gene transfers, bacteria are becoming increasingly resistant to these drugs bacteria are becoming increasingly resistant to these drugs. There is an urgent need for alternative approaches to combat harmful bacteria.

How does a very small motor direct bacteria? Think of bacteria as tiny boats that have propellors but no rudders. This means that their propellers have to be able to guide the direction. These specialized propellors are called flagella, which resemble Indiana Jones-style whips. Depending on how the bacteria rotate the flagella, these features can both serve to move the bacteria forward and change the direction of swimming. At the base of each of the flagella is a very small and extremely efficient rotary motor that controls this direction of flagellar rotation and is the key to the entire process.

To visualize and understand the inner workings of the bacterial flagellar motor our recent research used a technique called cryo-electron microscopy. We captured and analyzed millions of pictures of these bacterial nano-motors at 100,000-fold magnification. We then combined them to reconstruct models of the different states of the motor which are shown here: https://youtu.be/sGiVNUN2ypg. Our results suggest that the motor uses interlaced cogwheels to change how the flagella rotate and guide the bacteria https://youtu.be/MsPPyNWhqPoh . We can also propose how this nano-motor can accept torque from multiple sources so that bacteria can swim at different speeds (https://www.youtube.com/watch?v=_TLm5aoy3PM).

We are here today on Reddit to answer your questions about our findings, experiences, future directions, and more.

We will be here to take your questions from 12-1PM ET (1600-1700 UTC). Ask us anything!

Useful links:

• Published paper: https://doi.org/10.1038/s41564-024-01674-1
• Behind the paper: https://communities.springernature.com/posts/a-leap-from-bioenergetics-to-chemotaxis
• https://pubmed.ncbi.nlm.nih.gov/36423648/
• Learn more about Iverson Lab: https://lab.vanderbilt.edu/iverson-lab/
• Follow Iverson Lab: u/iverson_lab
• Follow Prash on Twitter/X: https://twitter.com/prash_singh

Back in 2020, it seemed like every scientist on the planet was working simultaneously, full steam ahead, on the Covid-19 vaccine. Thankfully, they produced one - actually, more than one. Thank you science! At the time, there was a lot of talk that there could someday be a universal vaccine that could prevent or block infection from ALL variants of Covid-19, or, even better, from all coronaviruses.

Four years later, where do we stand now? Has any progress been made on this? Are we getting closer to a universal Covid vaccine? Do scientists even care about Covid at all anymore? We never hear about Covid or vaccine research in the news anymore. Meanwhile, millions of people are still being infected with it every year, and the most vulnerable are still dying.

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Physics, Astronomy, Earth and Planetary Science

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

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Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

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Past AskAnythingWednesday posts can be found here. Ask away!

Hearing over and over again that the bird flu "risk to the public is low" is vaguely comforting, though I can't help but feel irritated at hearing the same placid response every time it impacts a new mammal, infects another person, or is found to be more widespread than had previously been thought (as today's headlines mentioned, via the dairy herds).

Is there a way to actually measure the range of the likelihood of a mutation that would allow to easy person-to-person spread of the bird flu?

And along the same lines - are epidemiologists concerned about this? Irritated at useless and uninformed headlines that overstate the risk? Stocking up on canned goods?

Seems like a no brainer to manufacture a vaccine for the current H5N1 strain in case it acquires additional mutations for human to human spread. There’ll likely be some kind of immunity even if it’s not perfectly matching a strain that has mutated. Are flu vaccine committees looking into this? It could be rolled into this fall’s seasonal vaccine schedule. As far as I know the technology has already been developed and approved.

Is it theoretically possible that a potato chips driven motor with 86kg of potato chips would have the same range as an electric powered motor with a battery of 55kWh?

I was watching a documentary about Phlegraean Fields in Italy and they said that when it erupted 39 thousands years ago, the eruption column reached about 30km high (18 miles).

So I was wondering, how do they know how tall it was? What do they do to determine its height?

Happy Earth Week to all who celebrate — although every day is Earth Day here at EPA! I’m new to Reddit, but I’m ready to dive in. We all know those icebreakers when you first meet people can be a little awkward, but in this case, I think it’s important to give you rundown:

• I'm the first Black man and second person of color to ever lead the EPA. It's fun when things come full circle, because I started my career at the agency as an intern (don't ask me how long it's been).
• I'm originally from Goldsboro, North Carolina and a proud graduate of NC A&T. Aggie pride!
• Like many people, my passion for the environment developed while exploring the outdoors as a kid. I would hunt and fish with my father and grandfather in rural North Carolina, and I love seeing that same spark of

curiosity in my own 10-year-old son now.

• As a member of President Biden's cabinet, I've had the honor of traveling to 30+ states and 13 countries meeting with folks who care deeply about protecting public health and the environment.
• Just like anyone starting a new job, I had a big list of goals in mind - tackling climate change, advancing environmental justice - but my philosophy comes down to this... I want to make sure all people have clean

air to breathe, clean water to drink, and the opportunity to lead a healthy life. It's really that simple!

We’ve had a busy few weeks at the agency – just yesterday we announced the selectees for our $7 billion dollar Solar for All program, which follows our $20 billion dollar Greenhouse Gas Reduction Fund announcement from two weeks ago! We’ve also finalized stronger pollution standards for cars and trucks, banned ongoing uses of asbestos, protected 100 million people from PFAS in drinking water, and made good on a promise to folks in Cancer Alley and overburdened communities across the nation by slashing cancer-causing pollution from chemical plants. There’s lots to talk about, and that’s why I’m so excited to be here today... so ask me anything!

Proof

PS. If anyone has tips for a good baseball pitch, I’ll also take that – I'm throwing the first pitch at the National-Dodgers game tonight and want to throw a pitch as strong as our plan to fight climate change.

Administrator Regan will begin answering questions at 2pm EST (18 UT)

Username: /u/EPAMichaelRegan

My impression might be affected by (understandable) media hype, but it seems prion diseases are very infectious. However the digestive system is quite harsh and is supposed to not let through foreign bodies larger than relatively small molecules. How come prion diseases are able to be transmitted effectively through food?

By now most people will have noticed or at least heard that, along with the overall decline in wildlife populations, pollinators are vanishing at alarming rates. Can we already observe plants adapting to this or not, and if so, what do we see?

Hi everyone. Learning about electromagnetism in physics. Not sure if I’m crazy, but do we really gloss over why a magnetic field points north to be clockwise around a current carrying wire? Do we know anything more about how or why it points clockwise other than “that’s just how it goes.”

For background, this came up when doing Oersted’s “compass experiment.” The compass sat idle pointing to earth’s north. Then current is suddenly run through the above wire and the north of the compass snaps from the earth’s north into a position always pointing north as clockwise relative to the direction of current (right hand rule direction).

So we know by experiment that this true. But do we know how it’s true, or is it more of a ‘brute force’ fact? It’s this always that gets me.

And the fact it’s so clear through such a simple experiment - compass points to the earth’s north, current is run through wire, compass snaps into north as clockwise, always clockwise, to the direction of convention current in wire.

Thanks all!

Tldr: Why does a magnetic field around a current-carrying wire always point clockwise, as observed in Oersted's compass experiment?

Ultimately why are we perceiving the world as right-side up? What evolutionary benefit does this have and how would it affect us if down was up and up was down. Since we created these orientations to begin with wouldn't we function just as well?

Some vending machines offer vacuum/airtight packaged meals that stay good for a week or longer. Other vending machines offer freshly made meals in non-airtight containers claiming it's good for a week or so. But is that possible? If so, what's the difference between me making a meal and storing it versus the way they make and store it that makes it safe to store it for more than 2 days?

As I understand the protons formed into a Nuclei like hydrogen and helium, but were there protons that just exist out there?

I understand escape velocity is the velocity at which an object needs to be travelling to 'escape' another object's gravity, given no other forces are acting on it.

But, the range of gravity is infinite, it just falls off at the square of distance. So no matter how far away the escaping object is, it will always feel some small pull back towards the object it's escaping, even if it's infinitessimal. Therefore given enough time and obviously no other object to capture it, it will fall back even if its initial velocity was above escape velocity.

Is escape velocity an approximation given the realities of the universe (at some point the gravitational pull is so small it will be captured by another object) or have I missed something?

EDIT: Thank you for all the great answers, I understand this now. I should learn calculus.

I've long read that the inner core was solid due to pressure, but this quote got me thinking: "since this layer is able to transmit shear waves (transverse seismic waves), it must be solid". But since the outer core is liquid, how could seismic waves be able to travel through the core anyway?

As I am about to donate stem cells for a person with a disease of the hematopoietic system, I am currently very interested in the topic and would like to understand more, but I am not completely familiar with the subject. When selecting a donor, attention is paid to various HLA characteristics in order to have a 10/10 match in the best case scenario.

Is it a coincidence that unrelated donors and recipients have the same HLA characteristics?

And the second question is probably clarified by the answer to the first question and the fact that even siblings only have a 25% chance of being suitable donors: is there a possibility of a distant relationship if some (or all?) HLA characteristics match?

Perhaps someone has an explanation for me, in detail if possible, or any websites, papers or anything else that explains this in more detail.

https://qz.com/drug-resistant-bacteria-international-space-station-1851421829

A group of researchers took a closer look at bacterial strains on board the ISS and found that they had mutated to a different form that’s genetically and functionally distinct from their Earthly counterparts. In a new study published on PubMed, scientists suggest that bacteria in space becomes more resistant to treatment or drugs, and are able to openly persist in the microgravity environment in abundance.

Will this change procedures of quarantine after being in space?

Why do some mountains have soil on top, while others are made of rocks? Does the elevation have do with it? It seems than the taller the mountain, the more likely that its peak is made of rocks?

Can anything perfectly smooth exist or be made? A single plane of atoms that remain level and stable along the entirety of that axis? has it been observed on some level?

I was listening to a podcast - which admittedly isn't the most informative or "correct" - when the hosts started talking about climate change and potential solutions. They joked they could "take the heat and move it somewhere else" when one of them realized that, with the carbon better capturing the heat, we really can't get rid of it?

The problem of climate change, from what I understand, is that the atmosphere is trapping CO2 at a higher rate. There's excess energy in an enclosed environment. If it was localized weather, I guess we could just "move it away." However, this energy is everywhere which kinda' screws us, I assume.

Clearly, my understanding of climate change is lacking.

I recently heard a clip of a professor saying that matter is frozen light. If this is the case, what force is strong enough to “freeze” light? Gravity? Dark matter? I’m intrigued. Thanks!

Follow up question: Why was there an Ancestral Rocky Mountains (again in the middle of the continent) unless there was some other previous oceanic plate subduction?

My limited knowledge is that NASA no longer paints the external tank to save paint, money, and weight. But that begs the question, why paint them white at all? Sorry if this is a stupid question, I'm not too knowledgeable on rocket stuff but this has been on my mind for a bit.

Most things in the body have some symmetry or something but the small intestines just seem like a jumbled mass. Are they are more logically laid out in the body then they appear in medical drawings or is there some other method behind the madness.

Why does arm and leg hair stop growing at a certain length, whereas head hair seems to have no limit to its growth?