We need to translate Russian news post into natural English, format per rules.
First line: short headline under 90 chars, no markdown, no '#'.
Then blank line, then body split into short paragraphs (2-3 sentences each), separated by blank lines.
Wrap few genuinely important facts — key numbers, percentages, drug/company/gene names, dates — in double asterisks . At most 4-5 per post, never a whole sentence.
Wrap study/journal citations and publication references in single underscores (e.g. Nature Aging, July 2026).
We need to preserve all facts, numbers, names, citations exactly.
Let's identify facts:
- Review introduced "arrhythmic zone" – temperature interval where internal clocks lose autonomous rhythm, but cell/organism still viable.
- Review published August 24 in The FEBS Journal.
- Authors compiled data from bacteria to mammals, propose separating temperature at which clocks lose autonomous rhythm from lower temperature limit of viability.
- Circadian clocks – intracellular mechanisms setting ~daily rhythm.
- In some temperature range, rhythm remains close to daily, though individual biochemical reactions go faster or slower. This property is temperature compensation.
- Review asks what happens below this boundary when rhythm no longer sustains itself, but cell/organism still viable.
- "We call 'arrhythmic zone' the interval in which viability is preserved while autonomous rhythm weakens or disappears."
- This is well seen in experiment with cyanobacterial proteins.
- In 2017 experiment, three purified proteins KaiA, KaiB, KaiC mixed in test tube: mechanism that creates daily oscillations.
- Upon cooling to 19°C, rhythmic changes in KaiC became weaker and smoothly went to zero, while cycle length almost unchanged.
- This transition is called Hopf bifurcation: amplitude of autonomous oscillations decays, period almost preserved.
- Protein system still responded to environmental temperature cycles; strongest entrainment by cycle close to its own 24‑h rhythm.
- In arrhythmic zone, external repeating signal can still drive rhythm of mechanism that lost autonomous drive.
- Review also mentions more complex systems.
- In thin slices of mouse suprachiasmatic nucleus (SCN) – brain area that sets rhythm for whole body – at 15°C rhythmic calcium changes and gene expression stopped; after rewarming they resumed.
- In culture of human U2OS cells, viability remained high at 25–37°C, while around 30°C the rhythm of luminescence of genetic reporter BMAL1-dLuc, which tracks clock work, disappeared.
- In six participants, hair follicle cells retained similar amplitude of clock gene activity after a day at 18 and 28°C; authors linked this to blood flow smoothing temperature of living tissue.
- In cell culture temperature is set by medium; in living tissue it is smoothed by blood flow.
- Now for each organism we can seek three different temperatures: lower viability limit, limit of autonomous rhythm, limit of rhythm still supported by external daily signal.
- Especially interesting are psychrophiles – organisms that grow best at 15°C and below.
- In polar cyanobacteria already found kaiABC genes linked to bacterial clocks.
- Authors propose to measure their autonomous rhythm at native temperature and compare three thresholds in cold‑adapted organisms.
We need to wrap key numbers, percentages, drug/company/gene names, dates in double asterisks. At most 4-5 per post.
Select maybe: August 24, The FEBS Journal, 19 °C, 15 °C, 25–37 °C, 30 °C, 18 °C, 28 °C, kaiABC. That's many; need limit to 4-5. Choose most important: date, journal, key temperatures (maybe 19°C, 15°C, 30°C), gene name kaiABC. That's 5.
We can wrap each in double asterisks.…
🔗 Read original →
PubMed Central (PMC)
Low temperature nullifies the circadian clock in cyanobacteria through Hopf bifurcation
Loss of circadian rhythms of poikilotherms or plants occurs widely at low temperatures. Here we chilled the simplest circadian oscillator reconstituted in a test tube and found that a reduction in amplitude abrogated rhythmicity, which transitioned ...
August 26, 2026 2
