Lifeboat Foundation

It is a commonly accepted view that light stimulation of mammalian photoreceptors causes a graded change in membrane potential instead of developing a spike. The presynaptic Ca²⁺ channels serve as a crucial link for the coding of membrane potential variations into neurotransmitter release. Ca_v1.4 L-type Ca²⁺ channels are expressed in photoreceptor terminals, but the complete pool of Ca²⁺ channels in cone photoreceptors appears to be more diverse. Here, we discovered, employing whole-cell patch-clamp recording from cone photoreceptor terminals in both sexes of mice, that their Ca²⁺ currents are composed of low-(T-type Ca²⁺ channels) and high-(L-type Ca²⁺ channels) voltage-activated components. Furthermore, Ca²⁺ channels exerted self-generated spike behavior in dark membrane potentials, and spikes were generated in response to light/dark transition. The application of fast and slow Ca²⁺ chelators revealed that T-type Ca²⁺ channels are located close to the release machinery. Furthermore, capacitance measurements indicated that they are involved in evoked vesicle release. Additionally, RT-PCR experiments showed the presence of Ca_v3.2 T-type Ca²⁺ channels in cone photoreceptors but not in rod photoreceptors. Altogether, we found several crucial functions of T-type Ca²⁺ channels, which increase the functional repertoire of cone photoreceptors. Namely, they extend cone photoreceptor light-responsive membrane potential range, amplify dark responses, generate spikes, increase intracellular Ca²⁺ levels, and boost synaptic transmission.

SIGNIFICANCE STATEMENT Photoreceptors provide the first synapse for coding light information. The key elements in synaptic transmission are the voltage-sensitive Ca²⁺ channels. Here, we provide evidence that mouse cone photoreceptors express low-voltage-activated Ca_v3.2 T-type Ca²⁺ channels in addition to high-voltage-activated L-type Ca²⁺ channels. The presence of T-type Ca²⁺ channels in cone photoreceptors appears to extend their light-responsive membrane potential range, amplify dark response, generate spikes, increase intracellular Ca²⁺ levels, and boost synaptic transmission. By these functions, Ca_v3.2 T-type Ca²⁺ channels increase the functional repertoire of cone photoreceptors.

Scientists trained a machine learning tool to capture the physics of electrons moving on a lattice using far fewer equations than would typically be required, all without sacrificing accuracy. A daunting quantum problem that until now required 100,000 equations has been compressed into a bite-size task of as few as four equations by physicists using artificial intelligence. All of this was accomplished without sacrificing accuracy. The work could revolutionize how scientists investigate systems containing many interacting electrons. Furthermore, if scalable to other problems, the approach could potentially aid in the design of materials with extremely valuable properties such as superconductivity or utility for clean energy generation.

From an AI that makes videos from text prompts to a robot running track, check out this week’s awesome tech stories from around the web.

SEOUL, South Korea — North Korea on Tuesday fired an intermediate-range ballistic missile over Japan, its neighbors said, escalating tests of weapons designed to strike key targets in regional U.S. allies.

It is the most significant missile test by North Korea since January, when it fired the Hwasong-12 intermediate-range missile capable of reaching the U.S. territory of Guam. It is also the first time that a North Korean missile has flown over Japan since 2017.

The Japanese prime minister’s office said at least one missile fired from North Korea flew over Japan and was believed to have landed in the Pacific Ocean.

Researchers at Google Deepmind and the University of Oxford have concluded that it’s now “likely” that superintelligent AI will spell the end of humanity — a grim scenario that more and more researchers are starting to predict.

In a recent paper published in the journal AI Magazine, the team — comprised of DeepMind senior scientist Marcus Hutter and Oxford researchers Michael Cohen and Michael Osborne — argues that machines will eventually become incentivized to break the rules their creators set to compete for limited resources or energy.

“Under the conditions we have identified, our conclusion is much stronger than that of any previous publication — an existential catastrophe is not just possible, but likely,” Cohen, Oxford University engineering student and co-author of the paper, tweeted earlier this month.

Clouds are made of silicate minerals.

The clouds of the distant brown dwarf contain silicate material, making it a quite unusual atmospheric composition.

Scientists have discovered a fluorescent protein that flouts trade-off relationships.

Scientific research institute RIKEN produced bright and photostable green fluorescent protein from Japanese jellyfish. Published in Nature Biotechnology.

Proteins that emit green light when illuminated are effective instruments for capturing images of intricate cell architecture. Such fluorescent proteins can be attached to target structures of interest, which light up when exposed to blue light.

Continue reading “Japanese scientists produce bright and photostable green fluorescent protein from jellyfish” »

Peering incredibly far back into time, astronomers found a group of much older stars than they expected.

Astronomers made a new discovery in the very first full-color image released from the James Webb Space Telescope.

Continue reading “Astronomers may have found some of the very earliest stars thanks to James Webb” »