A new antibiotic hits germs with a two pronged attack.
- Antibiotic resistance is a big problem, but not many new drugs are currently under development.
- A recent discovery may give us a new antibiotic that is effective against a wide range of germs, including those resistant to other drugs.
- The new drug's mechanism also appears to signal the immune system, helping to amplify its response.
The delicate art of carpet bombing bacteria<p> The trick with finding any antibiotic is to identify a substance that can damage bacterial cells without also harming the cells of the animal they are making sick. This is a relatively simple concept, but a difficult problem to get around. </p><p>Researchers at the <a href="https://wistar.org/" target="_blank" rel="noopener noreferrer">Wistar Institute</a> dealt with it by selecting something unique to bacteria, which was important in their functioning to focus on, and then finding chemicals that would disrupt it. They chose a metabolic pathway, known as the non-mevalonate pathway, which is used to create molecules necessary for the bacteria cell to survive. They then selected an enzyme in this pathway, the <a href="https://en.wikipedia.org/wiki/4-Hydroxy-3-methylbut-2-enyl_diphosphate_reductase" target="_blank" rel="noopener noreferrer">IspH</a> enzyme, to target specifically.</p><p>Using computer models, the researchers screened several million existing compounds and substances to determine which ones would bind to IspH and then began experiments with the most promising candidates. A new, synthetic IspH inhibitor was created as a result of this.</p>
How it works<p>The molecules that IspH helps to make are required in bacteria for respiration and repairing the cell wall. When this new antibiotic attaches to them and keeps them from doing their job, the cell either dies because it can't breathe or keep its insides in, or it stays alive but is unable to function normally. Both of these methods are commonly seen in other antibiotics. By either killing off the germs or slowing them down, they give the immune system time to step up and keep the infection under control.</p><p>The antibiotic was also found to amplify the response of the immune system. In tests involving mice, <a href="https://en.wikipedia.org/wiki/Gamma_delta_T_cell" target="_blank">Gamma Delta T-cells</a>, an important part of the immune system, activated at higher rates, often leading to better outcomes. This effect appears to be caused by the disruption to the bacteria; their impaired function caused them to signal themselves to the immune system.</p><p>This gives the new drug a dual function, which is hypothesized to not only make it quite effective but also may help prevent bacteria from developing resistance to it. It is thought that bacteria being hit from both directions are less likely to mutate responses to both.</p><p>IspH is a common enzyme in bacteria. Unlike some antibiotics, which are effective only against a narrow range of similar germs, this one may prove effective against a wide variety of microbes includes ones that are resistant to other drugs.</p><p>The researchers are, justly, proud of their discovery. Farokh Dotiwala, the study's lead author, suggested the finding may be more than just the discovery of a new drug in a <a href="https://wistar.org/news/press-releases/wistar-reports-new-class-antibiotics-active-against-wide-range-bacteria" target="_blank" rel="noopener noreferrer">press release:</a></p><p>"We believe this innovative DAIA strategy may represent a potential landmark in the world's fight against AMR, creating a synergy between the direct killing ability of antibiotics and the natural power of the immune system."</p>
So, I presume I can get this tomorrow?<iframe width="730" height="430" src="https://www.youtube.com/embed/iKCjqII0UQU" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><p> Not quite. This was an initial study conducted in mice, various kinds of plasma, and in test tubes. </p><p>While the results were promising, it will take some time before further studies are conducted and the drug becomes widely available. Additionally, while the study suggests the new drugs may be more effective against certain kinds of bacteria than existing antibiotics, exactly how well it works in humans remains to be seen.</p><p>Beyond that, if it is used as a front line drug or as a last resort is still to be determined. Future circumstances, dictated by what diseases we'll face, will likely answer that question.</p>
The microbes that eventually produced the planet's oxygen had to breathe something, after all.
- We owe the Earth's oxygen to ancient microbes that photosynthesized and released it into the world's oceans.
- A long-standing question has been: Before oxygen, what did they breathe?
- The discovery of microbes living in a hostile early-Earth-like environment may provide the answer.
Unassuming but remarkable microbial mats<p> Photosynthesis chiefly requires sunlight, water, and CO<sup>2</sup>. The CO<sup>2</sup> gets broken down into carbon and oxygen — the plant uses some of this oxygen and releases the rest. Without oxygen molecules, though, how did this work? </p><p> There are known microbial mats today that live in oxygen-free environments, but they're not thought to be sufficiently like their ancestors to explain ancient photosynthesis in an oxygen-free environment. </p><p> There have been a few oxygen stand-ins proposed. Photosynthesis can work with iron molecules, but fossil-record evidence doesn't support that idea. Hydrogen and sulphur have also been proposed, though evidence for them is also lacking. </p><p> The spotlight began to shift to arsenic in the first decade of the millennium when arsenic-breathing microbial mats were discovered in two hypersaline California lakes, <a href="https://science.sciencemag.org/content/308/5726/1305.abstract" target="_blank">Searles Lake</a> and <a href="https://www.discovermagazine.com/planet-earth/mono-lake-bacteria-build-their-dna-using-arsenic-and-no-this-isnt-about-aliens" target="_blank" rel="noopener noreferrer">Mono Lake</a>. In 2014, Visscher and colleagues <a href="https://www.nature.com/articles/ngeo2276" target="_blank">unearthed indications</a> of arsenic-based photosynthesis, or "arsenotrophic," microbial mats deep in the fossil record of the Tumbiana Formation of Western Australia. </p><p> Still, given the ever-shifting geology of the planets, the fractured ancient fossil record makes definitive study of ancient arsenotrophic photosynthesis difficult. The fossil record can't identify the role of the arsenic it reveals: was it involved in photosynthesis or just a toxic chemical that happened to be there? </p><p>Then, last year, arsenic-breathing microorganisms <a href="https://www.washington.edu/news/2019/05/01/arsenic-breathing-life-discovered-in-the-tropical-pacific-ocean/" target="_blank" rel="noopener noreferrer">were discovered</a> in the Pacific Ocean. A sulphur bacterium, <em>Ectothiorhodospira sp.</em> was also recently found to be metabolizing arsenic into <a href="https://en.wikipedia.org/wiki/Arsenite" target="_blank">arsenite</a> in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5064118/" target="_blank" rel="noopener noreferrer">Big Soda Lake</a> in Nevada. </p>
An ancient Earth environment, today<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ0NzIxMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1OTQwOTYyN30.v96ZRXpIAf4yzDwcvXzVV3Fa4qULtUMxanXguPHD2wI/img.jpg?width=980" id="9eec4" class="rm-shortcode" data-rm-shortcode-id="a23585c057ee50ed500b96125e4a6b05" data-rm-shortcode-name="rebelmouse-image" data-width="2873" data-height="1640" />
a Map of Northern Chile; b Detail of frame showing Laguna La Brava in the southern Atacama; c The channel showing the mats in purple; d Hand sample, cross-section; e Microscopic image of bacteria.
Credit: Visscher, et al./Communications Earth & Environment<p>The study reports on Visscher's discovery of a living microbial mat thriving in an arsenic environment in Laguna La Brava in the Atacama Desert in Chile. "We started working in Chile," Visscher tells <a href="https://today.uconn.edu/2020/09/without-oxygen-earths-early-microbes-relied-arsenic-sustain-life/" target="_blank"><em>UConn Today</em></a>, "where I found a blood-red river. The red sediments are made up by <a href="https://en.wikipedia.org/wiki/Anoxygenic_photosynthesis" target="_blank">anoxogenic</a> photosynthetic bacteria. The water is very high in arsenic as well. The water that flows over the mats contains hydrogen sulfide that is volcanic in origin and it flows very rapidly over these mats. There is absolutely no oxygen."</p><p>The mats had not previously been studied, and the conditions in which they live are tantalizingly similar to those of early Earth. It's a high-altitude, permanently oxygen-free state with extreme temperature swings and lots of UV exposure. </p><p>The mats that somewhat resemble Nevada's purple <em>Ectothiorhodospira sp.</em> are going about their business of making carbonate deposits, forming new stromatolites. Most excitingly, those deposits contain evidence that the mats are metabolizing arsenic. The rushing waters surrounding the mats are also rich in hydrogen sulphide and arsenic.</p><p>Says Visscher, "I have been working with microbial mats for about 35 years or so. This is the only system on Earth where I could find a microbial mat that worked absolutely in the absence of oxygen."</p><p>Not that Earth is the only place where this could happen. Visscher notes that the equipment they used for studying the Laguna La Brava mats is not unlike the system aboard the Mars Perseverance Rover. "In looking for evidence of life on Mars, they will be looking at iron, and probably they should be looking at arsenic also."</p>
An intriguing theory explains animals' magnetic sense.
- Some animals can navigate via magnetism, though scientists aren't sure how.
- Research shows that some of these animals contain magnetotactic bacteria.
- These bacteria align themselves along the magnetic field's grid lines.
Magnetotactic bacteria hosts<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQyMTQ2Ny9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2MDcwMTYxMn0.BZ-cpaTejm38_HCvVoSZ92k58dxnQETahNmKOmB14X4/img.jpg?width=980" id="c6097" class="rm-shortcode" data-rm-shortcode-id="a9f01b7583442ad92a05927c79754f50" data-rm-shortcode-name="rebelmouse-image" alt="whale mother and calf" data-width="1440" data-height="960" />
A right whale mother and calf
Credit: wildestanimal/Shutterstock<p>One of the paper's authors, Geneticist <a href="https://sciences.ucf.edu/biology/person/robert-fitak/" target="_blank">Robert Fitak</a>,<a href="https://sciences.ucf.edu/biology/person/robert-fitak/" target="_blank" rel="noopener noreferrer"></a> is affiliated with the biology department of the <a href="https://www.ucf.edu" target="_blank">University of Central Florida</a> in (UCF) Orlando. Prior to joining the department, he spent four years as a postdoctoral researcher at Duke University investigating the genomic mechanisms responsible for magnetic perception in fish and lobsters.</p><p>Fitak tells <a href="https://www.ucf.edu/news/animals-magnetic-sixth-sense-may-come-from-bacteria-new-paper-suggests/" target="_blank">UFC Today</a>, "The search for a mechanism has been proposed as one of the last major frontiers in sensory biology and described as if we are 'searching for a needle in a needle stack.'"</p><p>That metaphorical needle stack may well be the scientific community's largest database of microbes, the <a href="https://bmcgenomics.biomedcentral.com/articles/10.1186/1471-2164-9-75" target="_blank" rel="noopener noreferrer">Metagenomic Rapid Annotations using Subsystems Technology database</a>. It lists the animal samples in which magnetotactic bacteria have been found.</p><p>The primary use of the database, says Fitak, has been the measurement of bacterial diversity in entire phyla. An accounting of the appearance of magnetotactic bacteria in individual species is something that has previously be unexplored. "The presence of these magnetotactic bacteria had been largely overlooked, or 'lost in the mud' amongst the massive scale of these datasets," he reports.</p><p>Fitak dug into the database and discovered that magnetotactic bacteria have indeed been identified in a number of species known to navigate by magnetism, among them loggerhead sea turtles, Atlantic right whales, bats, and penguins. <em>Candidatus Magnetobacterium bavaricum</em> is regularly found in loggerheads and penguins, while <em>Magnetospirillum</em> and <em>Magnetococcus</em> are common among right whales and bats.</p><p>As for other magnetic-field-sensitive animals, he says, "I'm working with the co-authors and local UCF researchers to develop a genetic test for these bacteria, and we plan to subsequently screen various animals and specific tissues, such as in sea turtles, fish, spiny lobsters and birds."</p>
The bacteria-host relationship<p>While the presence of the bacteria in these particular species is intriguing, further study is needed to be sure they're responsible for other animals' magnetic navigation. Their presence in these species <em>could</em> be just a coincidence.</p><p>Fitak also notes that he doesn't know at this point exactly where in the host animal the magnetotactic bacteria would reside, or other details of their symbiotic relationship. He suggests that they might be found in nervous tissue associated with navigation, such as that found in the brain or eye.</p><p>If confirmed, Fitak's hypothesis could suggest that our own sensitivity to the Earth's magnetic field might one day be enhanced via magnetotactic bacteria in our own individual microbiomes, should they be benign to us as hosts.</p>
Various studies examine the impact of humidity, temperature, rain, and sunshine on COVID-19.
- Researchers around the world have been working to analyze and understand this virus since the global pandemic started earlier this year.
- While the first SARS-CoV virus (2003) did not circulate long enough for researchers to distinguish any specific seasonal pattern, daily weather did have an impact on the number of cases.
- Other studies from China, Australia, Brazil, and the UK take a look at how our weather can impact the transmission of COVID-19.
How does weather impact virus transmission?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzU5OTg4OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNTU1NjA2MX0.SvtcZz2PxVjC9AFLhC0sRpMDbcFp-RkAPJhuwTsZyWg/img.jpg?width=1245&coordinates=0%2C0%2C0%2C0&height=700" id="dae19" class="rm-shortcode" data-rm-shortcode-id="92f1bc5a03e54cc3f2f981acd09d14e2" data-rm-shortcode-name="rebelmouse-image" alt="COVID-19 virus SARS-CoV-2 under microscope weather virus" data-width="1245" data-height="700" />
How does weather impact the COVID-19 virus?
Image by MIA Studio on Shutterstock<p><strong>Studies of the first SARS-CoV (in 2003) might help us understand.</strong><br></p><p>While this virus did not circulate long enough for researchers to distinguish any specific seasonal pattern, daily weather did have an impact on the number of cases. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2870397/" target="_blank" rel="noopener noreferrer">According to this study</a>, new cases of SARS-CoV were 18x higher in lower temperatures (under 24.6°C). </p><p><strong>Cold weather impacts your likelihood of getting sick in different ways. </strong></p><p>One factor, according to <a href="https://sciencing.com/cold-weather-affect-immunity-22739.html" target="_blank" rel="noopener noreferrer">Sciencing</a>, that may increase your susceptibility in cold weather is how your sinuses respond to the humidity and temperature changes. Your nose is a natural air filter for your body. When you spend time in cold temperatures, your nasal passages dry out due to the constriction of blood vessels. When you return to warmer temperatures (like coming inside after time spent out in the cold), the sudden influx of moisture can cause your nose to run.</p><p>This usually forces you to breathe through your mouth, robbing you of the filter and making you susceptible to viruses or bacteria in the air. </p><p><strong>Cold weather = more time spent indoors, which can increase the likelihood of transmission.</strong></p><p>Regardless of the weather, it takes exposure to a virus to get a virus. One common reason why virus infections may become more common during cold months is that more people are spending time indoors (and together). </p><p><a href="https://bigthink.com/politics-current-affairs/social-distancing-math" target="_self">As research has determined</a>, social distancing can heavily impact the spread of the COVID-19 virus. Being clustered closer together indoors can increase the likelihood of transmission, giving the effect of the virus spreading faster in the colder months. </p>
The weather and COVID-19 studies from around the globe<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzU5OTg5MC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNTcwNzgxNH0.t5SY7q3HULHvoWIz5SpPA-DnPHjcgZqa0fANRn8ksxI/img.jpg?width=1245&coordinates=0%2C52%2C0%2C52&height=700" id="fb167" class="rm-shortcode" data-rm-shortcode-id="f3c84c531fb1b51decdb63e5f4a7c516" data-rm-shortcode-name="rebelmouse-image" alt="concept of condensation humidity impact COVID-19 condensation on window" data-width="1245" data-height="700" />
How do things like humidity, rainfall and sunshine impact the spread of COVID-19?
Photo by matuska on Shutterstock<p>Laboratory and observational studies of COVID-19 patients have shown there is an impact of humidity on SARS-COV-2.</p><p><strong>Humidity and its impact on COVID-19:</strong></p><p><a href="https://wwwnc.cdc.gov/eid/article/26/9/20-1806_article#r7" target="_blank" rel="noopener noreferrer">A lab-generated aerosol of SARS-CoV-2</a> was stable at a humidity of 53 percent at room temperature (23°C). The virus had not degenerated much, even after 16 hours, and was more robust than SARS-CoV. </p><p>Although laboratory studies cannot be used to explicitly explain how the virus will act in the real world, these findings are very important in deepening our understanding of the virus and its transmission. </p><p><a href="https://www.sciencedirect.com/science/article/pii/S004896972032026X?via%3Dihub" target="_blank" rel="noopener noreferrer">Another study in China</a> (with more than 50 cases of COVID-19) found a link between humidity and reductions in COVID-19 cases. In this simulation, the team measured humidity as absolute humidity (the total amount of water in the air) and found that for every gram per cubic meter in absolute humidity, there was a 67 percent reduction in COVID-19 cases after a lag of 14 days. </p><p>Similar studies (with similar results) have been conducted in <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/tbed.13631" target="_blank" rel="noopener noreferrer">Australia</a>.</p><p><strong>Rainfall and its impact on COVID-19:</strong></p><p>Rainfall may also impact the spread of the virus. <a href="https://www.sciencedirect.com/science/article/pii/S0048969720325146?via%3Dihub" target="_blank" rel="noopener noreferrer">Research out of Brazil</a> looked at rainfall worldwide and confirmed a pattern: for each average inch per day of rain, there was an increase of 56 COVID-19 cases per day. There was no link found between the COVID-19 deaths and rainfall. </p><p><strong>Sunshine and its impact on COVID-19: </strong></p><p>A Spain study found (after 5 days of lockdown) the longer the hours of sunshine, the more cases there were of the virus. This positive association held true with a lag (between sunshine hours and cases) of both 8 and 11 days. </p><p>However, it's important to note that this actually contradicts findings from Influenza research, which suggests a lower transmission with longer hours of sunshine. While influenza and COVID-19 are obviously different, it's interesting to note this contrast, as they are both viral infections.</p><p><strong>While all of these studies are interesting, does it really prove COVID-19 is impacted by weather? </strong></p><p><a href="https://www.medrxiv.org/content/10.1101/2020.05.21.20108803v1" target="_blank" rel="noopener noreferrer">Research out of Oxford</a> actually lists reasons why people should not use these observational studies on the weather and COVID-19 cases to establish if the virus is more or less transmittable based on the season. </p><p>While it's important to note that there are still things we don't know about COVID-19 and that each country has different testing and studying methods, the more we know about how this virus behaves in different climates the more we can work to prevent further infection. </p>
A new study shows bacteria could survive travel from Earth to Mars.