Tag Archives: E. coli

Australian peacock spiders, photonic nanostructures, and making money

Researcher Bor-Kai Hsiung’s work has graced this blog before but the topic was tarantulas and their structural colour. This time, it’s all about Australian peacock spiders and their structural colour according to a December 22, 2017 news item on ScienceDaily,

Even if you are arachnophobic, you probably have seen pictures or videos of Australian peacock spiders (Maratus spp.). These tiny spiders are only 1-5 mm long but are famous for their flamboyant courtship displays featuring diverse and intricate body colorations, patterns, and movements.

The spiders extremely large anterior median eyes have excellent color vision and combine with their bright colors to make peacock spiders cute enough to cure most people of their arachnophobia. But these displays aren’t just pretty to look at, they also inspire new ways for humans to produce color in technology.

One species of peacock spider — the rainbow peacock spider (Maratus robinsoni) is particularly neat, because it showcases an intense rainbow iridescent signal in males’ courtship displays to the females. This is the first known instance in nature of males using an entire rainbow of colors to entice females. Dr. Bor-Kai Hsiung led an international team of researchers from the US (UAkron, Cal Tech, UC San Diego, UNL [University of Nebraska-Lincoln]), Belgium (Ghent University), Netherlands (UGroningen), and Australia to discover how rainbow peacock spiders produce this unique multi-color iridescent signal.

A December 22, 2017 Ghent University (Belgium) press release on Alpha Galileo, which originated the news item, provides more technical detail,

Using a diverse array of research techniques, including light and electron microscopy, hyperspectral imaging, imaging scatterometry, nano 3D printing and optical modeling, the team found the origin of this intense rainbow iridescence emerged from specialized abdominal scales of the spiders. These scales have an airfoil-like microscopic 3D contour with nanoscale diffraction grating structures on the surface.

The interaction between the surface nano-diffraction grating and the microscopic curvature of the scales enables separation and isolation of light into its component wavelengths at finer angles and smaller distances than are possible with current manmade engineering technologies.

Inspiration from these super iridescent scales can be used to overcome current limitations in spectral manipulation, and to further reduce the size of optical spectrometers for applications where fine-scale spectral resolution is required in a very small package, notably instruments on space missions, or wearable chemical detection systems. And it could have a wide array of implications to fields ranging from life sciences and biotechnologies to material sciences and engineering.

Here’s a video of an Australian rainbow peacock spider,

Here’s more from the YouTube description published on April 13, 2017 by Peacockspiderman,

Scenes of Maratus robinsoni, a spider Peter Robinson discovered and David Hill and I named it after him in 2012. You can read our description on pages 36-41 in Peckhamia 103.2, which can be downloaded from the Peckhamia website http://peckhamia.com/peckhamia_number…. This is one of the two smallest species of peacock spider (2.5 mm long) and the only spider we know of in which colour changes occur every time it moves, this video was created to document this. Music: ‘Be Still’ by Johannes Bornlöf licensed through my MCN ‘Brave Bison’ from ‘Epidemic Sound’ For licensing inquiries please contact Brave Bison licensing@bravebison.io

The University of California at San Diego also published a December 22, 2017 news release about this work, which covers some of the same ground while providing a few new tidbits of information,

Brightly colored Australian peacock spiders (Maratus spp.) captivate even the most arachnophobic viewers with their flamboyant courtship displays featuring diverse and intricate body colorations, patterns, and movements – all packed into miniature bodies measuring less than five millimeters in size for many species. However, these displays are not just pretty to look at. They also inspire new ways for humans to produce color in technology.

One species of peacock spider – the rainbow peacock spider (Maratus robinsoni) – is particularly impressive, because it showcases an intense rainbow iridescent signal in males’ courtship displays to females. This is the first known instance in nature of males using an entire rainbow of colors to entice females to mate. But how do males make their rainbows? A new study published in Nature Communications looked to answer that question.

Figuring out the answers was inherently interdisciplinary so Bor-Kai Hsiung, a postdoctoral scholar at Scripps Institution of Oceanography at the University of California San Diego, assembled an international team that included biologists, physicists and engineers. Starting while he was a Ph.D. student at The University of Akron under the mentorship of Todd Blackledge and Matthew Shawkey, the team included researchers from UA, Scripps Oceanography, California Institute of Technology, and University of Nebraska-Lincoln, the University of Ghent in Belgium, University of Groningen in Netherlands, and Australia to discover how rainbow peacock spiders produce this unique iridescent signal.

The team investigated the spider’s photonic structures using techniques that included light and electron microscopy, hyperspectral imaging, imaging scatterometry and optical modeling to generate hypotheses about how the spider’s scale generate such intense rainbows. The team then used cutting-edge nano 3D printing to fabricate different prototypes to test and validate their hypotheses. In the end, they found that the intense rainbow iridescence emerged from specialized abdominal scales on the spiders. These scales combine an airfoil-like microscopic 3D contour with nanoscale diffraction grating structures on the surface. It is the interaction between the surface nano-diffraction grating and the microscopic curvature of the scales that enables separation and isolation of light into its component wavelengths at finer angles and smaller distances than are possible with current engineering technologies.

“Who knew that such a small critter would create such an intense iridescence using extremely sophisticated mechanisms that will inspire optical engineers,” said Dimitri Deheyn, Hsuing’s advisor at Scripps Oceanography and a coauthor of the study.

For Hsiung, the finding wasn’t quite so unexpected.

“One of the main questions that I wanted to address in my Ph.D. dissertation was ‘how does nature modulate iridescence?’ From a biomimicry perspective, to fully understand and address a question, one has to take extremes from both ends into consideration. I purposefully chose to study these tiny spiders with intense iridescence after having investigated the non-iridescent blue tarantulas,” said Hsiung.

The mechanism behind these tiny rainbows may inspire new color technology, but would not have been discovered without research combining basic natural history with physics and engineering, the researchers said.

“Nanoscale 3D printing allowed us to experimentally validate our models, which was really exciting,” said Shawkey. “We hope that these techniques will become common in the future.”

“As an engineer, what I found fascinating about these spider structural colors is how these long evolved complex structures can still outperform human engineering,” said Radwanul Hasan Siddique, a postdoctoral scholar at Caltech and study coauthor. “Even with high-end fabrication techniques, we could not replicate the exact structures. I wonder how the spiders assemble these fancy structural patterns in the first place!”

Inspiration from these super iridescent spider scales can be used to overcome current limitations in spectral manipulation, and to reduce the size of optical spectrometers for applications where fine-scale spectral resolution is required in a very small package, notably instruments on space missions, or wearable chemical detection systems.

In the end, peacock spiders don’t just produce nature’s smallest rainbows.They could also have implications for a wide array of fields ranging from life sciences and biotechnologies to material sciences and engineering.

Before citing the paper and providing a link, here’s a story by Robert F. Service for Science magazine about attempts to capitalize on ‘spider technology’, in this case spider silk,

The hype over spider silk has been building since 1710. That was the year François Xavier Bon de Saint Hilaire, president of the Royal Society of Sciences in Montpellier, France, wrote to his colleagues, “You will be surpriz’d to hear, that Spiders make a Silk, as beautiful, strong and glossy, as common Silk.” Modern pitches boast that spider silk is five times stronger than steel yet more flexible than rubber. If it could be made into ropes, a macroscale web would be able to snare a jetliner.

The key word is “if.” Researchers first cloned a spider silk gene in 1990, in hopes of incorporating it into other organisms to produce the silk. (Spiders can’t be farmed like silkworms because they are territorial and cannibalistic.) Today, Escherichia coli bacteria, yeasts, plants, silkworms, and even goats have been genetically engineered to churn out spider silk proteins, though the proteins are often shorter and simpler than the spiders’ own. Companies have managed to spin those proteins into enough high-strength thread to produce a few prototype garments, including a running shoe by Adidas and a lightweight parka by The North Face. But so far, companies have struggled to mass produce these supersilks.

Some executives say that may finally be about to change. One Emeryville, California-based startup, Bolt Threads, says it has perfected growing spider silk proteins in yeast and is poised to turn out tons of spider silk thread per year. In Lansing, Michigan, Kraig Biocraft Laboratories says it needs only to finalize negotiations with silkworm farms in Vietnam to produce mass quantities of a combination spider/silkworm silk, which the U.S. Army is now testing for ballistics protection. …

I encourage you to read Service’s article in its entirety if the commercialization prospects for spider silk interest you as it includes gems such as this,

Spider silk proteins are already making their retail debut—but in cosmetics and medical devices, not high-strength fibers. AMSilk grows spider silk proteins in E. coli and dries the purified protein into powders or mixes it into gels, for use as additives for personal care products, such as moisture-retaining skin lotions. The silk proteins supposedly help the lotions form a very smooth, but breathable, layer over the skin. Römer says the company now sells tons of its purified silk protein ingredients every year.

Finally, here’s a citation for and a link to the paper about Australian peacock spiders and nanophotonics,

Rainbow peacock spiders inspire miniature super-iridescent optics by Bor-Kai Hsiung, Radwanul Hasan Siddique, Doekele G. Stavenga, Jürgen C. Otto, Michael C. Allen, Ying Liu, Yong-Feng Lu, Dimitri D. Deheyn, Matthew D. Shawkey, & Todd A. Blackledge. Nature Communications 8, Article number: 2278 (2017) doi:10.1038/s41467-017-02451-x Published online: 22 December 2017

This paper is open access.

As for Bor-Kai Hsiung’s other mentions here:

How tarantulas get blue (December 7, 2015 posting)

Noniridescent photonics inspired by tarantulas (October 19, 2016 posting)

More on the blue tarantula noniridescent photonics (December 28, 2016 posting)

Bacteria and an anti-superbug coating from Ireland’s Sligo Institute of Technology

Unlike today’s (April 28, 2016) earlier piece about dealing with bacteria, the focus for this research is on superbugs and not the bacteria which form biofilm on medical implants and such. An April 21, 2016 news item on RTE News makes the announcement about a new means of dealing with superbugs,

A discovery by a team of scientists in Ireland could stem the spread of deadly superbugs predicted to kill millions of people worldwide over the coming decades.

The research has found an agent that can be baked into everyday items like smart-phones and door handles to combat the likes of MRSA and E. coli.

The nanotechnology has a 99.9 % kill rate of potentially lethal and drug-resistant bacteria, they say.

Lead scientist Professor Suresh C. Pillai, of Sligo Institute of Technology’s Nanotechnology Research Group, says the discovery is the culmination of 12 years work.

“This is a game changer,” he said.

“This breakthrough will change the whole fight against superbugs. It can effectively control the spread of bacteria.”

An April 21, 2016 Sligo Institute of Technology press release provides some context for the work and a few details about the coating,

News of the discovery comes just days after UK Chancellor of the Exchequer George Osborne warned that superbugs could become deadlier than cancer and are on course to kill 10 million people globally by 2050.

Speaking at the International Monetary Fund (IMF) in Washington, Mr Osborne warned that the problem would slash global GDP by around €100 trillion if it was not tackled.

Using nanotechnology, the discovery is an effective and practical antimicrobial solution — an agent that kills microorganisms or inhibits their growth — that can be used to protect a range of everyday items.

Items include anything made from glass, metallics and ceramics including computer or tablet screens, smartphones, ATMs, door handles, TVs, handrails, lifts, urinals, toilet seats, fridges, microwaves and ceramic floor or wall tiles.

It will be of particular use in hospitals and medical facilities which are losing the battle against the spread of killer superbugs.

Other common uses would include in swimming pools and public buildings, on glass in public buses and trains, sneeze guards protecting food in delis and restaurants as well as in clean rooms in the medical sector.

“It’s absolutely wonderful to finally be at this stage. This breakthrough will change the whole fight against superbugs. It can effectvely control the spread of bacteria,” said Prof. Pillai.

He continued: “Every single person has a sea of bacteria on their hands. The mobile phone is the most contaminated personal item that we can have. Bacteria grows on the phone and can live there for up to five months. As it is contaminated with proteins from saliva and from the hand, It’s fertile land for bacteria and has been shown to carry 30 times more bacteria than a toilet seat.”

The research started at Dublin Institute of Technology (DIT)’s CREST and involves scientists now based at IT Sligo, Dublin City University (DCU) and the University of Surrey. Major researchers included Dr Joanna Carroll and Dr Nigel S. Leyland.

It has been funded for the past eight years by John Browne, founder and CEO of Kastus Technologies Ltd, who is bringing the product to a global market. He was also supported by significant investment from Enterprise Ireland.

As there is nothing that will effectively kill antibiotic-resistant superbugs completely from the surface of items, scientists have been searching for a way to prevent the spread.

This has been in the form of building or ‘baking’ antimicrobial surfaces into products during the manufacturing process.

However, until now, all these materials were toxic or needed UV light in order to make them work. This meant they were not practical for indoor use and had limited commercial application.

“The challenge was the preparation of a solution that was activated by indoor light rather than UV light and we have now done that,” said Prof Pillai.

The new water-based solution can be sprayed onto any glass, ceramic or metallic surface during the production process, rendering the surface 99.9 per cent resistant to superbugs like MRSA, E. coli and other fungi. [emphasis mine]

The solution is sprayed on the product — such as a smartphone glass surface — and then ‘baked’ into it, forming a super-hard surface. The coating is transparent, permanent and scratch resistant and actually forms a harder surface than the original glass or ceramic material.

The team first developed the revolutionary material to work on ceramics and has spent the last five years adapting the formula – which is non-toxic and has no harmful bi-products ‑- to make it work on glass and metallic surfaces.

Research is now underway by the group on how to adapt the solution for use in plastics and paint, allowing even wider use of the protective material.

Prof Pillai, Kastus and the team have obtained a US and a UK patent on the unique process with a number of global patent applications pending. It is rare for such an academic scientific discovery to have such commercial viability.

“I was sold on this from the first moment I heard about it. It’s been a long road to here but it was such a compelling story that it was hard to walk away from so I had to see it through to the end,” said John Browne, Kastus CEO.

He continued: “This is a game changer. The uniqueness of antimicrobia surface treatment means that the applications for it in the real world are endless. The multinational glass manufacturers we are in negotiations with to sell the product to have been searching for years to come up with such a solution but have failed.”

If the coating kills 99.9%, doesn’t that mean 0.1% are immune? If that’s the case, won’t they reproduce and eventually establish themselves as a new kind of superbug?

Here’s a link to and a citation for the paper,

Highly Efficient F, Cu doped TiO2 anti-bacterial visible light active photocatalytic coatings to combat hospital-acquired infections by Nigel S. Leyland, Joanna Podporska-Carroll, John Browne, Steven J. Hinder, Brid Quilty, & Suresh C. Pillai. Scientific Reports 6, Article number: 24770 (2016) doi:10.1038/srep24770 Published online: 21 April 2016

This paper is open access.

Greening silver nanoparticles with lignin

A July 13, 2015 news item on phys.org highlights a new approach to making silver nanoparticles safer in the environment,

North Carolina State University researchers have developed an effective and environmentally benign method to combat bacteria by engineering nanoscale particles that add the antimicrobial potency of silver to a core of lignin, a ubiquitous substance found in all plant cells. The findings introduce ideas for better, greener and safer nanotechnology and could lead to enhanced efficiency of antimicrobial products used in agriculture and personal care.

A July 13, 2015 North Carolina State University (NCSU) news release (also on EurekAlert), which originated the news item, adds a bit more information,

As the nanoparticles wipe out the targeted bacteria, they become depleted of silver. The remaining particles degrade easily after disposal because of their biocompatible lignin core, limiting the risk to the environment.

“People have been interested in using silver nanoparticles for antimicrobial purposes, but there are lingering concerns about their environmental impact due to the long-term effects of the used metal nanoparticles released in the environment,” said Velev, INVISTA Professor of Chemical and Biomolecular Engineering at NC State and the paper’s corresponding author. “We show here an inexpensive and environmentally responsible method to make effective antimicrobials with biomaterial cores.”

The researchers used the nanoparticles to attack E. coli, a bacterium that causes food poisoning; Pseudomonas aeruginosa, a common disease-causing bacterium; Ralstonia, a genus of bacteria containing numerous soil-borne pathogen species; and Staphylococcus epidermis, a bacterium that can cause harmful biofilms on plastics – like catheters – in the human body. The nanoparticles were effective against all the bacteria.

The method allows researchers the flexibility to change the nanoparticle recipe in order to target specific microbes. Alexander Richter, the paper’s first author and an NC State Ph.D. candidate who won a 2015 Lemelson-MIT prize, says that the particles could be the basis for reduced risk pesticide products with reduced cost and minimized environmental impact.

“We expect this method to have a broad impact,” Richter said. “We may include less of the antimicrobial ingredient without losing effectiveness while at the same time using an inexpensive technique that has a lower environmental burden. We are now working to scale up the process to synthesize the particles under continuous flow conditions.”

I don’t quite understand how the silver nanoparticles/ions are rendered greener. I gather the lignin is harmless but where do the silver nanoparticles/ions go after they’ve been stripped of their lignin cover and have killed the bacteria? I did try reading the paper’s abstract (not much use for someone with my science level),

Silver nanoparticles have antibacterial properties, but their use has been a cause for concern because they persist in the environment. Here, we show that lignin nanoparticles infused with silver ions and coated with a cationic polyelectrolyte layer form a biodegradable and green alternative to silver nanoparticles. The polyelectrolyte layer promotes the adhesion of the particles to bacterial cell membranes and, together with silver ions, can kill a broad spectrum of bacteria, including Escherichia coli, Pseudomonas aeruginosa and quaternary-amine-resistant Ralstonia sp. Ion depletion studies have shown that the bioactivity of these nanoparticles is time-limited because of the desorption of silver ions. High-throughput bioactivity screening did not reveal increased toxicity of the particles when compared to an equivalent mass of metallic silver nanoparticles or silver nitrate solution. Our results demonstrate that the application of green chemistry principles may allow the synthesis of nanoparticles with biodegradable cores that have higher antimicrobial activity and smaller environmental impact than metallic silver nanoparticles.

If you can explain what happens to the silver nanoparticles, please let me know.

Meanwhile, here’s a link to and a citation for the paper,

An environmentally benign antimicrobial nanoparticle based on a silver-infused lignin core by Alexander P. Richter, Joseph S. Brown, Bhuvnesh Bharti, Amy Wang, Sumit Gangwal, Keith Houck, Elaine A. Cohen Hubal, Vesselin N. Paunov, Simeon D. Stoyanov, & Orlin D. Velev. Nature Nanotechnology (2015) doi:10.1038/nnano.2015.141 Published online 13 July 2015

This paper is behind a paywall.

Customizing bacteria (E. coli) into squares, circles, triangles, etc.

The academic paper for this latest research from Delft University of Technology (TU Delft, Netherlands), uses the term ‘bacterial sculptures,’ an intriguing idea that seems to have influenced the artistic illustration accompanying the research announcement.

Artistic rendering live E.coli bacteria that have been shaped into a rectangle, triangle, circle, and square (from front to back). Colors indicate the density of the Min proteins that represent a snapshot in time (based on actual data), as these proteins oscillate back and forth within the bacterium, to determine the mid plane of the cell for cellular division. Image credit:  ‘Image Cees Dekker lab TU Delft / Tremani’

Artistic rendering live E.coli bacteria that have been shaped into a rectangle, triangle, circle, and square (from front to back). Colors indicate the density of the Min proteins that represent a snapshot in time (based on actual data), as these proteins oscillate back and forth within the bacterium, to determine the mid plane of the cell for cellular division.
Image credit: ‘Image Cees Dekker lab TU Delft / Tremani’

A June 22, 2015 news item on Nanowerk provides more insight into the research (Note: A link has been removed),

The E.coli bacterium, a very common resident of people’s intestines, is shaped as a tiny rod about 3 micrometers long. For the first time, scientists from the Kavli Institute of Nanoscience at Delft University have found a way to use nanotechnology to grow living E.coli bacteria into very different shapes: squares, triangles, circles, and even as letters spelling out ‘TU Delft’. They also managed to grow supersized E.coli with a volume thirty times larger than normal. These living oddly-shaped bacteria allow studies of the internal distribution of proteins and DNA in entirely new ways.

In this week’s Nature Nanotechnology (“Symmetry and scale orient Min protein patterns in shaped bacterial sculptures”), the scientists describe how these custom-designed bacteria still manage to perfectly locate ‘the middle of themselves’ for their cell division. They are found to do so using proteins that sense the cell shape, based on a mathematical principle proposed by computer pioneer Alan Turing in 1953.

A June 22, 2015 TU Delft press release, which originated the news item, expands on the theme,

Cell division

“If cells can’t divide properly, biological life wouldn’t be possible. Cells need to distribute their cell volume and genetic materials equally into their daughter cells to proliferate.”, says prof. Cees Dekker, “It is fascinating that even a unicellular organism knows how to divide very precisely. The distribution of certain proteins in the cell is key to regulating this, but how exactly do those proteins get that done?”

Turing

As the work of the Delft scientist exemplifies, the key here is a process discovered by the famous Alan Turing in 1953. Although Turing is mostly known for his role in deciphering the Enigma coding machine and the Turing Test, the impact of his ‘reaction-diffusion theory’ on biology might be even more spectacular. He predicted how patterns in space and time emerge as the result of only two molecular interactions – explaining for instance how a zebra gets its stripes, or how an embryo hand develops five fingers.

MinD and MinE

Such a Turing process also acts with proteins within a single cell, to regulate cell division. An E.coli cell uses two types of proteins, known as MinD and MinE, that bind and unbind again and again at the inner surface of the bacterium, thus oscillating back and forth from pole to pole within the bacterium every minute. “This results in a low average concentration of the protein in the middle and high concentrations at the ends, which drives the division machinery to the cell center”, says PhD-student Fabai Wu, who ran the experiments. “As our experiments show, the Turing patterns allow the bacterium to determine its symmetry axes and its center. This applies to many bacterial cell shapes that we custom-designed, such as squares, triangles and rectangles of many sizes. For fun, we even made ‘TUDelft’ and ‘TURING’ letters. Using computer simulations, we uncovered that the shape-sensing abilities are caused by simple Turing-type interactions between the proteins.”

Actual data for live E.coli bacteria that have been shaped into the letters TUDELFT.
The red color shows the cytosol contents of the cell, while the green color shows the density of the Min proteins, representing a snapshot in time, as these proteins oscillate back and forth within the bacterium to determine the mid plane of the cell for cellular division. The letters are about 5 micron high.
Image credit:  ‘Fabai Wu, Cees Dekker lab at TU Delft’

Spatial control for building synthetic cells

“Discovering this process is not only vital for our understanding of bacterial cell division – which is important in developing new strategies for antibiotics. But the approach will likely also be fruitful to figuring out how cells distribute other vital systems within a cell, such as chromosomes”, says Cees Dekker. “The ultimate goal in our research is to be able to completely build a living cell from artificial components, as that is the only way to really understand how life works. Understanding cell division – both the process that actually pinches off the cell into two daughters and the part that spatially regulates that machinery – is a major part of that.”

Here’s a link to and a citation for the paper,

Symmetry and scale orient Min protein patterns in shaped bacterial sculptures by Fabai Wu, Bas G. C. van Schie, Juan E. Keymer, & Cees Dekker. Nature Nanotechnology (2015) doi:10.1038/nnano.2015.126 Published online 22 June 2015

This paper is behind a paywall but there does seem to be another link (in the excerpt below) which gives you a free preview via ReadCube Access (according to the TU Delft press release),

The DOI for this paper will be 10.1038/nnano.2015.126. Once the paper is published electronically, the DOI can be used to retrieve the abstract and full text by adding it to the following url: http://dx.doi.org/

Enjoy!

New molecular ruler could help with developing antibiotics

Researchers at the University of Utah have developed a molecular ruler which could help to determine the length at which a nanoscale needle is effective. From a March 17, 2015 news item on Azonano,

When a salmonella bacterium attacks a cell, it uses a nanoscopic needle to inject it with proteins to aid the infection. If the needle is too short, the cell won’t be infected. Too long, and the needle breaks. Now, University of Utah biologists report how a disposable molecular ruler or tape measure determines the length of the bacterial needle so it is just right.

The findings have potential long-term applications for developing new antibiotics against salmonella and certain other disease-causing bacteria, for designing bacteria that could inject cancer cells with chemotherapy drugs, and for helping people how to design machines at the nanoscopic or molecular scale.

A March 16, 2015 University of Utah news release, which originated the news item, provides some insight from the researchers,

“If you look at important pathogens – the bubonic plague bacterium, salmonella, shigella and plant pathogens like fire blight – they all use hypodermic-like needles to inject proteins that facilitate disease processes,” Hughes [University of Utah biology professor Kelly Hughes] says.

“Our work says that there is one mechanism – the molecular ruler – to explain how the lengths are controlled for needles in gram-negative bacteria and for hooks on flagella [the U-joints in propellers bacteria use to move] in all bacteria,” he adds.

In their study, Wee [University of Utah doctoral student Daniel Wee] and Hughes found that as a bacterial needle or “injectisome” grows, a molecular ruler – really, more like a gooey tape measure – is secreted from within the needle’s base. It oozes up through the tube-like needle, and when the bottom end of the ruler reaches the bottom end of the needle, the needle stops growing and begins to inject proteins into the target cell to help the infection process.

The biologists say the [US] National Institutes of Health-funded study refutes other theories for how salmonella and some other disease bacteria determine needle lengths.

The news release also explains how this finding could be made useful,

“What we understand from bacteria can help us build nanomachines and nanobots,” Hughes says, noting that bacterial flagella – the nanoscopic motor-and-propeller system they use to swim to dinner or to targets – are “the most sophisticated nanomachines in the universe.”

In one example, Swiss scientists are using the design of bacterial flagella as the basis for a nanobot that will be put inside the eye to do nanoscale surgery, he adds.

In addition to flagella, a number of disease-causing bacteria also have injectisomes, which also are built of proteins, as are most structures in living organisms.

“In the case of the needle, you have a structure that extends from the surface of the bacterium like a hypodermic,” Hughes says. “These needles are fragile. If one is too long, it will break off and be useless. If you make it too short, then it can’t get past the surface proteins on cells it needs to invade.”

By understanding how bacteria determine the length for their needles, it someday may be possible to engineer bacteria to inject chemotherapy drugs right into cancer cells.

“People would like to design bacteria that can get to cancer cells and inject poisons into just those cells and kill them, and not harm the rest of us,” Hughes says.

And by understanding how certain disease-causing bacteria build their injectisomes, new antibiotics might be developed in a decade or so to target and destroy the needles and thus deter bacterial infections. The rulers that help build flagella also might be attacked by drugs to prevent bacteria from reaching target cells, “so you can kill two birds with one stone by hitting the two machines at the same time,” Hughes says.

He says that approach might work against injectisome-equipped bacteria such as salmonella species that cause typhoid fever and food poisoning; shigella species that cause dysentery; the bubonic plague bacterium Yersinia pestis; disease-causing E. coli; sexually transmitted Chlamydia trachomatis; many plant pathogens; and Pseudomonas aeruginosa, which often infects burn patients and the lungs of cystic fibrosis patients.

Not usually my kind of thing, I find this quite fascinating (from the news release),

Bacteria secrete a molecular ruler to measure needle length

Bacterial injectisomes are incredibly small, measuring only 20 to 100 nanometers long. A nanometer is one billionth of a meter, and a meter is about 39 inches long. The width of a typical human hair often is given as 100 microns, so the maximum length of a bacterial needle, 100 nanometers, is one-thousandth of the width of a human hair.

Gram-negative, disease-causing bacteria “are very closely related species, so how do they subtly control the various needle lengths to be perfect?” Hughes asks. “In one case it might be 40 nanometers versus 55 nanometers. These are small sizes. So to do this, the bacteria developed molecular rulers to differentiate needles of different lengths.”

(Gram-negative bacteria are those with membranes lining both the inside and outside of their cell wall, while gram-positive bacteria have only an inner membrane.)

Like any cell, a bacterium is encased in a cell wall. So bacteria developed all kinds of secretions to make contact with and infect other cells: flagellar propellers to swim to food or target cells, docking structures to help bacteria stick to targets, and injectisomes to inject infection-promoting proteins into targets.

When a bacterium builds a needle, it first builds a base. “A series of proteins form a doughnut, and inside the doughnut hole, the actual secretion machine gets constructed,” Hughes says. “It’s the same for the flagella as it is for these needles.”

Next, proteins start assembling to form the needle or injectisome.

The new study demonstrated that in salmonella, the ruler or tape measure is secreted slowly through the channel of the growing needle. Once amino acids at the bottom end of the ruler pass through the base of the needle, they tell the bacterium that the needle is long enough and to stop growing. They also tell the needle to injecting virulence proteins into the target cell, and the molecular ruler is ejected, Wee says.

Here’s an image of what the injectisome looks like,

On the left is an electron microscope image of an injectisome, the nanoscopic needle that salmonella and certain other bacteria use to inject proteins into target cells as part of the infection process. The illustration at center depicts the exterior of the needle and its base. The cross-section at right shows the string-like molecular ruler that determines the length of salmonella’s bacteria needle, according to a new University of Utah study by doctoral student Daniel Wee and biology professor Kelly Hughes. Credit: Daniel Wee, University of Utah

On the left is an electron microscope image of an injectisome, the nanoscopic needle that salmonella and certain other bacteria use to inject proteins into target cells as part of the infection process. The illustration at center depicts the exterior of the needle and its base. The cross-section at right shows the string-like molecular ruler that determines the length of salmonella’s bacteria needle, according to a new University of Utah study by doctoral student Daniel Wee and biology professor Kelly Hughes. Credit: Daniel Wee, University of Utah

The news release also offers some specific details about the research,

How the study was performed

The new study used the Typhimurium strain of Salmonella enterica, which causes food poisoning. The researchers proved the molecular ruler determines needle length in salmonella by inserting amino acids from the plague bacterium’s molecular ruler genes into genes for salmonella’s molecular ruler, making rulers with seven different lengths.

Genetically engineered salmonella with seven ruler lengths were grown in a flask, their needles isolated, and the needle lengths measured under an electron microscope.

Wee found the ruler lengths correlated precisely with the lengths of the resulting needles or injectisomes, with each amino acid added to the ruler gene making the resulting needle 0.2 nanometers longer.

Previous studies found the molecular ruler determines the length of the hook or U-joint that helps turn flagella or propellers in many bacteria. Research also found the molecular ruler determines the length of both the flagellar hook and the needle in plague bacteria. But some researchers argued salmonella needle’s length was determined by some other mechanism:

– One theory holds that a molecular measuring cup in the needle’s base sends a cupful of needle components to assemble the needle, and the length of the needle is determined by the size of the cup. The new study disproved that by genetically removing the cup and showing that the injectisomes or needles still grew to correct lengths.

– Another theory says that as needle components assemble outside the needle’s base, a rod-shaped structure assembles inside the base to link the base and needle, and that when the rod is complete, needle assembly stops, thus determining needle length. But the Utah study found the rod and needle components are not made simultaneously, but compete with each other, so as more rod parts are made, fewer needle parts are made, giving an illusion that rod completion controls needle length.

Here’s a link to and a citation for the paper,

Molecular ruler determines needle length for the Salmonella Spi-1 injectisome by Daniel H. Wee and Kelly T. Hughes. Published online before print March 16, 2015, doi: 10.1073/pnas.1423492112 PNAS March 16, 2015

This paper is behind a paywall.

 

MMA (mixed martial arts) and nano silver wound dressings

I had never, ever expected to mention mixed martial arts (MMA) here but that’s one of the delightful aspects of writing about nanotechnology; you never know where it will take you. A March 9, 2015 news item on Azonano describes the wound situation for athletes and a new product,

..

As an MMA Champion athlete, Rich Franklin knows all too well about germs and how easily they spread. During training he dealt with them on a regular basis, but it wasn’t until the first time he had staph, did he realize these infections could cost him a victory. Now, working in a global setting, Franklin trains in locations around the world which leaves him exposed to a plethora of bacteria and fungi. So he teamed up with American Biotech Labs (ABL) to develop Armor Gel, nano silver-based, wound dressing gel that can stay active on the skin for up to seventy-two hours (3 days). Using patented nano silver technology, Armor Gel has been scientifically tested to reduce the levels of bacteria and other pathogens, while forming a protective barrier “armor” over the wound. By shielding the body from external bacterial, the body’s natural healing process can be expedited. Its use is recommended by doctors, trainers, coaches, and athletes alike.

A March 6, 2015 ABL news release on BusinessWire, which originated the news item, provides a little more detail about Armor Gel,

Engineered for today’s modern athletes, Armor Gel is safe, nontoxic and provides a personal first line of defense. Already proven to reduce the levels of MRSA, VRE, pseudomonas aeruginosa, E. coli, A. niger and Candida albicans, Armor Gel is formulated using a unique and patented 24 SilverSol Technology®.

American Biotech Labs (ABL) was started in 2002 as a nano silver biotech company with the goal of creating a more stable and powerful silver technology for consumer products. …

I am providing a link to the product website (neither the link nor this post are endorsements), you can find out more about Armor Gel here.

Armor Gel was announced previously in a Sept. 16, 2014 ABL news release on PR Newswire, At the time no mention was made of Rich Franklin, their MMA athlete,

American Biotech Labs, LLC, is pleased to announce the availability of three new silver hydrogel wound-dressing products.  The new products will allow American Biotech Labs (ABL) to market in the wound-care market focusing on ultimate sports and fitness, spa and health, and animal markets.

The new over-the-counter (OTC) products will have wound-dressing claims for minor cuts, lacerations, abrasions, 1st and 2nd degree burns, and skin irritations.  The products also have pathogen-inhibiting barrier claims against pathogens, such as Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, MRSA and VRE, as well as fungi, such as Candida albicans and Aspergillus niger.  These new gels can provide a barrier that will help protect wounds for 24 to 72 hours.

The new products will be found under the names of Armor Gel™ (for the ultimate sports and fitness market), ASAP OTC™ (for the spa and health markets), and ASAP Pet Shield® (for the animal market).

Along with the release of these new products, ABL has formed a strategic alliance with Stuart Evey, founder and former chairman of ESPN, and Gary Bernstein, marketing executive and professional photographer and film maker.  ABL will utilize these talented individuals to help introduce these revolutionary new products to high-profile organizations in sports, pet stores, fashion and beauty, medical, and direct-marketing areas, etc.

Said Keith Moeller, ABL Director, “We are very grateful to the numerous top scientists, labs and universities that have helped move this amazing, patented, silver technology forward.  We believe that these products have the ability to impact the future of wound management worldwide.”

Note: Any statements released by American Biotech Labs, LLC that are forward looking are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.  Editors and investors are cautioned that forward looking statements invoke risk and uncertainties that may affect the company’s business prospects and performance.

You can find out more about ABL and its entire product line here.

Protecting food with copper nanoparticles

It’s usually silver nanoparticles protecting us from bacteria (sports clothing, bandages, food, socks,, etc.)  but this time, according to a July 24, 2013 news item on ScienceDaily, it’s copper,

Microbes lurk almost everywhere, from fresh food and air filters to toilet seats and folding money. Most of the time, they are harmless to humans. But sometimes they aren’t. Every year, thousands of people sicken from E. coli infections and hundreds die in the US alone. Now Michigan Technological University scientist Jaroslaw Drelich has found a new way to get them before they get us.

His innovation relies on copper, an element valued for centuries for its antibiotic properties. Drelich, a professor of materials science and engineering, has discovered how to embed nanoparticles of the red metal into vermiculite, an inexpensive, inert compound sometimes used in potting soil. In preliminary tests on local lake water, it killed 100 percent of E. coli bacteria in the sample. Drelich also found that it was effective in killing Staphylococcus aureus, the common staph bacteria.

The news item was originated by a March 18, 2013 Michigan Technical University news release by Marcia Goodrich (Note: It’s not unusual for an institution to resend a news release which didn’t get much notice the first time). Goodrich’s news release provides more details about Drelich’s commercialization plans for his work,

Bacteria aren’t the only microorganisms that copper can kill. It is also toxic to viruses and fungi. If it were incorporated into food packaging materials, it could help prevent a variety of foodborne diseases, Drelich says.

The copper-vermiculite material mixes well with many other materials, like cardboard and plastic, so it could be used in packing beads, boxes, even cellulose-based egg cartons.

And because the cost is so low—25 cents per pound at most—it would be an inexpensive, effective way to improve the safety of the food supply, especially fruits and vegetables. Drelich is working with the Michigan Tech SmartZone to commercialize the product through his business, Micro Techno Solutions, the recipient of the 2012 Great Lakes Entrepreneur’s Quest Food Safety Innovation Award. He expects to further test the material and eventually license it to companies that pack fresh food.

The material could have many other applications as well. It could be used to treat drinking water, industrial effluent, even sewage.  “I’ve had inquiries from companies interested in purifying water,” Drelich says.

And it could be embedded in products used in public places where disease transmission is a concern: toilet seats, showerheads, even paper toweling.

“When you make a discovery like this, it’s hard to envision all the potential applications,” he says. It could even be mixed into that wad of dollar bills in your wallet. “Money is the most contaminated product on the market.”

The research Drelich performed was discussed in a 2011 paper,

Vermiculite decorated with copper nanoparticles: Novel antibacterial hybrid material by Jaroslaw Drelich, Bowen Li, Patrick Bowen, Jiann-Yang Hwang, Owen Mills, Daniel Hoffman.  Applied Surface Science, Volume 257, Issue 22, 1 September 2011, Pages 9435–9443. http://dx.doi.org/10.1016/j.apsusc.2011.06.027

This paper is behind a paywall.

Sponging up the toxins in your blood

It doesn’t sound like these nanosponges are going to help you with your hangover but should you have a snakebite, an E. coli infection or other such pore-forming toxin in your blood, engineers at the University of California at San Diego are working on a solution. From the University of California at San Diego Apr. 14, 2103 news release,

Engineers at the University of California, San Diego have invented a “nanosponge” capable of safely removing a broad class of dangerous toxins from the bloodstream – including toxins produced by MRSA, E. coli, poisonous snakes and bees. These nanosponges, which thus far have been studied in mice, can neutralize “pore-forming toxins,” which destroy cells by poking holes in their cell membranes. Unlike other anti-toxin platforms that need to be custom synthesized for individual toxin type, the nanosponges can absorb different pore-forming toxins regardless of their molecular structures. In a study against alpha-haemolysin toxin from MRSA, pre-innoculation with nanosponges enabled 89 percent of mice to survive lethal doses. Administering nanosponges after the lethal dose led to 44 percent survival.

They’ve produced a video about their work,

I like the fact that this therapy isn’t specific but can be used for different toxins (from the news release),

“This is a new way to remove toxins from the bloodstream,” said Liangfang Zhang, a nanoengineering professor at the UC San Diego Jacobs School of Engineering and the senior author on the study. “Instead of creating specific treatments for individual toxins, we are developing a platform that can neutralize toxins caused by a wide range of pathogens, including MRSA and other antibiotic resistant bacteria,” said Zhang. The work could also lead to non-species-specific therapies for venomous snake bites and bee stings, which would make it more likely that health care providers or at-risk individuals will have life-saving treatments available when they need them most.

Here’s how the nanosponges work (from the news release),

In order to evade the immune system and remain in circulation in the bloodstream, the nanosponges are wrapped in red blood cell membranes. This red blood cell cloaking technology was developed in Liangfang Zhang’s lab at UC San Diego. The researchers previously demonstrated that nanoparticles disguised as red blood cells could be used to deliver cancer-fighting drugs directly to a tumor. …

Red blood cells are one of the primary targets of pore-forming toxins. When a group of toxins all puncture the same cell, forming a pore, uncontrolled ions rush in and the cell dies.

The nanosponges look like red blood cells, and therefore serve as red blood cell decoys that collect the toxins. The nanosponges absorb damaging toxins and divert them away from their cellular targets. The nanosponges had a half-life of 40 hours in the researchers’ experiments in mice. Eventually the liver safely metabolized both the nanosponges and the sequestered toxins, with the liver incurring no discernible damage. [emphasis mine]

It’s reassuring to see that this therapy doesn’t damage as it heals.

For those interested, here’s some technical information about how the nanosponges are created in the laboratory (from the news release),

Each nanosponge has a diameter of approximately 85 nanometers and is made of a biocompatible polymer core wrapped in segments of red blood cells membranes.

Zhang’s team separates the red blood cells from a small sample of blood using a centrifuge and then puts the cells into a solution that causes them to swell and burst, releasing hemoglobin and leaving RBC [red blood cell] skins behind. The skins are then mixed with the ball-shaped nanoparticles until they are coated with a red blood cell membrane.

Just one red blood cell membrane can make thousands of nanosponges, which are 3,000 times smaller than a red blood cell. With a single dose, this army of nanosponges floods the bloodstream, outnumbering red blood cells and intercepting toxins. Based on test-tube experiments, the number of toxins each nanosponge could absorb depended on the toxin. For example, approximately 85 alpha-haemolysin toxin produced by MRSA, 30 stretpolysin-O toxins and 850 melittin monomoers, which are part of bee venom.

In mice, administering nanosponges and alpha-haemolysin toxin simultaneously at a toxin-to-nanosponge ratio of 70:1 neutralized the toxins and caused no discernible damage.

This seems like promising work and, hopefully, they will be testing these nanosponges in human clinical trials soon.

Here’s a link to and a citation for the researchers’ paper,

A biomimetic nanosponge that absorbs pore-forming toxins by Che-Ming J. Hu, Ronnie H. Fang, Jonathan Copp, Brian T. Luk,& Liangfang Zhang. Nature Nanotechnology (2013) doi:10.1038/nnano.2013.54 Published online 14 April 2013

This paper is behind a paywall. (H/T to EurekAlert [Apr. 14, 2013 news release].)

The last time I wrote about nanosponges it was in the context of oil spills in my Apr. 17, 2012 posting.