Biology

Far from being solo operators, most single-celled microbes are in complex relationships. In the ocean, the soil and your gut, they might battle and eat each other, exchange DNA, compete for nutrients, or feed on one another’s by-products. Sometimes they get even more intimate: One cell might slip inside another and make itself comfortable. If the conditions are just right, it might stay and be welcomed, sparking a relationship that could last for generations — or billions of years. This phenomenon of one cell living inside another, called endosymbiosis, has fueled the evolution of complex life.

Examples of endosymbiosis are everywhere. Mitochondria, the energy factories in your cells, were once free-living bacteria. Photosynthetic plants owe their sun-spun sugars to the chloroplast, which was also originally an independent organism. Many insects get essential nutrients from bacteria that live inside them. And last year researchers discovered the “nitroplast,”(opens a new tab) an endosymbiont that helps some algae process nitrogen.

cross-posted from: https://lemmy.ca/post/33597552

Summary from the 404 media newsletter

Heart cockles, a group of marine molluscs, contain little communities of algae in their shells as part of a symbiotic relationship; the algae get shelter and protection, and the cockles get algae-processed nutrients.

Now, scientists have discovered that cockle shells have a host of mind-boggling adaptations to keep these algae happy, including windows that offer “the first example of fiber optic cable bundles in a living creature.”

“We show that the fibrous prismatic crystals act like parallel bundles of fiber optic cables in the shell windows, not just transmitting light but projecting high-resolution images through the window,” that have “a resolution of >100 lines/mm,” said researchers led by Dakota McCoy of the University of Chicago.

From the article in the link above:

Fig. 1: Heart cockles (Corculum cardissa and Corculum spp.) are asymmetrical, photosymbiotic bivalves.

Fig. 2: Transparent windows allow heart cockle shells to transmit 11–62% of photosynthetically active radiation (mean = 31%) and significantly screen out UV radiation (mean = 14%, range = 5–28%).

Key findings

Day vs. night habitat use: Barred owls' home ranges were significantly larger at night than during the day, indicating different habitat needs between their active and resting periods. The research emphasizes that preserving green spaces in urban areas can have profound effects on nocturnal and diurnal wildlife.

Energy efficiency in preferred habitats: Owls expended less energy in their preferred nocturnal habitats, suggesting that these areas provide higher-quality resources.

Affluent neighborhoods attract barred owls: Barred owls in Baton Rouge, Louisiana, showed a marked preference for habitats in affluent neighborhoods, supporting the "luxury effect"—the tendency for wealthier areas to harbor greater biodiversity.

Implications for Urban Design: The study advocates for providing and protecting habitat for barred owls to keep this important species, other forest-associated species, and the ecosystem services they provide present and functioning in urban areas. The study also advocates for the equitable distribution of green spaces in cities, especially in less affluent areas, to promote biodiversity throughout the urban landscape.

Irene Manton was a pioneer of electron microscopy.

She produced the first diagrammatic reconstruction of the 9+2 microtubular structure of the #cilium in 1952. When she showed her beautiful micrographs at international meetings, the audience would cheer and break into applause.

And she mortgaged her house to buy an electron microscope!

https://www.embrc.eu/newsroom/news/irene-manton-algal-cell-biologist-and-her-electron-microscope

#microscopy @biology #WomenInScience #science

cross-posted from: https://rss.ponder.cat/post/53510

Nice piece on a large zooplankton survey by Leonid Moroz in the Guardian https://www.theguardian.com/environment/2024/nov/05/ocean-genome-atlas-project-scientists-plankton-dna-secrets-human-biology-sailing-boats @biology #plankton

Many microbes and cells are in deep sleep, waiting for the right moment to activate.

Harsh conditions like lack of food or cold weather can appear out of nowhere. In these dire straits, rather than keel over and die, many organisms have mastered the art of dormancy. They slow down their activity and metabolism. Then, w

Sitting around in a dormant state is actually the norm for the majority of life on Earth: By some estimates, 60% of all microbial cells are hibernating at any given time. Even in organisms whose entire bodies do not go dormant, like most mammals, some cellular populations within them rest and wait for the best time to activate.

“Life is mainly about being asleep.”

Because dormancy can be triggered by a variety of conditions, including starvation and drought, the scientists pursue this research with a practical goal in mind: “We can probably use this knowledge in order to engineer organisms that can tolerate warmer climates,” Melnikov said, “and therefore withstand climate change.”

Balon is notably absent from Escherichia coli and Staphylococcus aureus, the two most commonly studied bacteria and the most widely used models for cellular dormancy. By focusing on just a few lab organisms, scientists had missed a widespread hibernation tactic, Helena-Bueno said. “I tried to look into an under-studied corner of nature and happened to find something.”

“Most microbes are starving,” said Ashley Shade, a microbiologist at the University of Lyon who was not involved in the new study. “They’re existing in a state of want. They’re not doubling. They’re not living their best life.”

“This is not something that’s unique to bacteria or archaea,” Lennon said. “Every organism in the tree of life has a way of achieving this strategy. They can pause their metabolism.”

“Before the invention of hibernation, the only way to live was to keep growing without interruptions,” Melnikov said. “Putting life on pause is a luxury.”

It’s also a type of population-level insurance. Some cells pursue dormancy by detecting environmental changes and responding accordingly. However, many bacteria use a stochastic strategy. “In randomly fluctuating environments, if you don’t go into dormancy sometimes, there’s a chance that the whole population will go extinct” through random encounters with disaster, Lennon said. In even the healthiest, happiest, fastest-growing cultures of E. coli, between 5% and 10% of the cells will nevertheless be dormant. They are the designated survivors who will live should something happen to their more active, vulnerable cousins.

More fundamentally, Melnikov and Helena-Bueno hope that the discovery of Balon and its ubiquity will help people reframe what is important in life. We all frequently go dormant, and many of us quite enjoy it. “We spend one-third of our life asleep, but we don’t talk about it at all,” Melnikov said. Instead of complaining about what we’re missing when we’re asleep, maybe we can experience it as a process that connects us to all life on Earth, including microbes sleeping deep in the Arctic permafrost.

cross-posted from: https://rss.ponder.cat/post/30414