Thursday, November 14, 2024

Exposure to Microgravity Seems to Seriously Disorient Human Sperm

13 Nov. 2024, By D. NIELD

(Rez-Art/iStock/Getty Images Plus)

Any future efforts humanity wants to make to populate the Universe outside our home planet may have a pretty significant hurdle to overcome: microgravity appears to confuse sperm about which direction they should be heading in.

A team led by researchers from the Technical University of Catalonia and Dexeus University Hospital in Spain collected 15 human sperm samples, splitting each sample in two: one-half of each sample stayed on Earth, whereas the other half was subjected to microgravity conditions through parabolic flights.

The sperm samples that took to the air and experienced gravity shifts showed significant decreases in motility (movement) and vitality (the number of live sperm). Microgravity didn't kill off the sperm, but it did cause some serious health issues.

Animal sperm experiments have already been carried out on the International Space Station. 
(NASA/Roscosmos)



"Even though it did not result in a total loss, heavy gravity load changes including microgravity cause a significant decrease in sperm vitality and motility, suggesting that negative consequences would be even higher if the exposure were longer," write the researchers in their published paper.

The curvilinear velocity of the sperm – how quickly they move towards their goal – was particularly affected, suggesting that the chances of a sperm fertilizing an egg are going to be noticeably lower in space compared to on Earth.

It wasn't all bad news, though: certain aspects of sperm health, including DNA fragmentation, sperm shape, oxidative stress, and apoptosis (programmed cell death) didn't seem to be impacted by the sperm's exposure to microgravity conditions.

While it's early days for this kind of research, it raises questions about reproduction in space: not just in the time-honored, traditional way, but also assisted reproduction techniques – such as in vitro fertilization (IVF) – that might be needed if we establish bases on the Moon or on Mars.

One of the questions that still needs answering is why microgravity has this effect on sperm, though the researchers think some kind of shift in the chemical processes needed to keep sperm healthy may be going on.

"More studies [are] needed before assisted reproduction techniques can be considered for the likelihood of human reproduction in space," write the researchers.

If we've got serious plans to establish long-term communities off Earth, then reproduction is going to be a big part of that. Understandably, sex hasn't so far been a top priority for astronauts leaving orbit, which leaves scientists mostly in the dark about its viability.

While animal studies have already hinted that conception might be tricky in microgravity, the team behind this work is keen to see more experiments carried out with human sperm – so we can learn more about how space life impacts our most basic biology.

"With the upcoming plans for extended space missions and growing interest in space tourism, the topic of possible likelihood of human conception under microgravity conditions has become even more relevant," write the researchers.


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Monday, November 4, 2024

Science News: UCLA chemists break 100-year-old rule, creating unstable organic molecules with distorted geometries

UCLA chemists break 100-year-old rule, creating unstable organic molecules with distorted geometries


The research team has successfully created molecules that violate Bredt's rule, opening up new possibilities in molecular design and pharmaceutical research.

By Jerusalem Post Staff, November 4, 2024


Chemistry laboratory. Image by U.S. Army Combat Capabilities Development Command is licensed under CC BY 2.0. (photo credit: FLICKR)


A new paper published on November 1, 2024, by UCLA scientists in the journal Science details a groundbreaking discovery that challenges a century-old principle in organic chemistry known as Bredt's rule. Led by Professor Neil Garg, a distinguished professor of chemistry and biochemistry at UCLA, the research team has successfully created molecules that violate Bredt's rule, opening up new possibilities in molecular design and pharmaceutical research.


Bredt's rule, established in 1924 by German chemist Julius Bredt, has been a guiding principle in organic chemistry for a hundred years. The rule states that a double bond cannot exist at the "bridgehead" position of a bridged bicyclic molecule because placing a double bond there would twist the molecule in unstable ways. This principle has been widely disseminated in academic texts and is recognized by the International Union of Pure and Applied Chemistry.


For decades, Bredt's rule has constrained chemists by preventing the placement of double bonds between carbon atoms in certain positions within complex molecular structures, particularly at the bridgehead position of bicyclic molecules. This limitation has restricted the types of synthetic molecules that scientists could imagine and create, notably impacting the exploration of olefins—hydrocarbons characterized by having one or more double bonds between two carbon atoms.


Professor Neil Garg's team set out to challenge this long-held assumption. "People aren't exploring anti-Bredt olefins because they think they can't," Garg noted. Deciding to question the rule's absolute nature, the team focused on creating anti-Bredt olefins (ABOs), the molecules that violate Bredt's rule.


The UCLA scientists developed a method to synthesize and stabilize these anti-Bredt olefins. They began with a type of molecule known as silyl (pseudo)halides and treated them with a fluoride source to produce the ABOs. Recognizing that anti-Bredt olefins are highly unstable, Garg’s lab included another chemical that can "trap" the unstable molecules. This approach allowed them to generate stable olefins that can be used in other chemical reactions, resulting in the production of several complex compounds that could be isolated and studied.


"What this study shows is that contrary to one hundred years of conventional wisdom, chemists can make and use anti-Bredt olefins to make value-added products," Garg explained. By trapping the anti-Bredt olefins, the team could capture them long enough to study them and use them to make new, valuable compounds. This breakthrough indicates that ABOs can be generated and utilized effectively, challenging the notion that they were inaccessible due to their instability.


The implications of this discovery are significant for drug development and pharmaceutical research. Since reactions using anti-Bredt olefins could lead to new types of medicines, the ability to create these previously "impossible" molecules opens up a new realm of compounds for scientists to explore. "There's a big push in the pharmaceutical industry to develop chemical reactions that give three-dimensional structures like ours because they can be used to discover new medicines," Garg emphasized.


By demonstrating that Bredt's rule is not as absolute as previously thought, the UCLA chemists suggest that their findings call for a textbook update. "It's time to rewrite the textbooks," Garg stated, raising questions about how often textbooks might be wrong in other ways. He further highlighted the importance of flexibility in scientific rules: "We shouldn't have rules like this—or if we have them, they should only exist with the constant reminder that they're guidelines, not rules. It destroys creativity when we have rules that supposedly can't be overcome."


This sentiment reflects a broader call to action within the scientific community to rethink long-held beliefs that may hinder innovation. By challenging Bredt's rule, Garg's team is advocating for a more flexible and innovative approach to chemistry, encouraging chemists to explore molecules that were previously considered impossible. "Breaking the rules can lead to groundbreaking discoveries," he noted, emphasizing that questioning established norms can lead to significant advancements in the field.


The study was authored by UCLA graduate students and postdoctoral scholars Luca McDermott, Zachary Walters, Sarah French, Allison Clark, Jiaming Ding, and Andrew Kelleghan. Distinguished research professor Ken Houk contributed to the study as a computational chemistry expert. The research was funded by the National Institutes of Health, providing new insights into how to create and use Bredt's rule-breaking olefins.


By opening the door to many new types of molecules that can be constructed and potentially prove useful, particularly in pharmaceuticals and materials science, Garg's team's discovery serves as a stepping stone to numerous possibilities in organic chemistry. It reminds us that science is always evolving, and sometimes, all it takes is a fresh perspective and a willingness to challenge the status quo to achieve breakthroughs. As Garg's work illustrates, questioning assumptions and pushing boundaries can lead to significant advancements that benefit a wide range of fields.


Sources: News18, Earth.com, Scitech Daily
This article was written in collaboration with generative AI company Alchemiq