Recording intelligenceAI-generated brief · check the source for context

Malaria Transmission Circadian Rhythms

1:05:36 recording · AUTO · 3 speakers

Listen to the original

Listen to the episode

Brief overview

Mosquito salivary glands and malaria sporozoites both run circadian clocks that make night-time transmission far more efficient.

  1. Salivary glands keep their own clockBetween 27 and 49% of salivary gland genes cycled, and cycling persisted in constant darkness, so time of day rather than light drives it.
  2. Quiescent sporozoites are still transcriptionally rhythmicA thymidine-analogue bioluminescence line found no cell division, so the 12 to 20% cycling transcripts are a real circadian rhythm, not replication.
  3. Night feeding transmits malaria betterNight-feeding mosquitoes ingested more blood with higher hemoglobin, and nighttime sporozoites into nighttime mice gave the highest liver parasite load.
Executive Summary AI
  • Vincent Racaniello records TWIP episode 260 on June 6 2025 with Daniel Griffin in New York and Christina Naula in Glasgow, marking Dixon de Pommier's birth anniversary and the 81st anniversary of D-Day.0:00
  • Christina presents an open-access Nature Microbiology paper, "Parasite and Vector Circadian Clocks Mediate Efficient Malaria Transmission", with first authors Ines Bento, Brianna Parrington and Ruchlin Pasqual, working in infected Anopheles stephensi carrying Plasmodium berghei.6:55
  • Dissecting salivary glands every four hours over three days, under 12-hour light-dark and constant-dark conditions, showed between 27 and 49% of salivary gland genes cycling, including anti-coagulation blood-feeding genes and the clock genes clock, cycle, period and Vrille.27:13
  • The quiescent, non-dividing salivary gland sporozoites turned out to be transcriptionally active too, with 12 to 20% of transcripts cycling, peaking early in the morning at a median threefold change, and over 50% of microneme-associated motility genes cycling.36:55
  • Mice infected intradermally with daytime sporozoites carried a reduced liver parasite load compared with nighttime sporozoites into nighttime mice, and the effect was abolished when the two were mismatched, while Daniel noted the missing control of uninfected mosquitoes.54:37
Key Quote
“I think they call this a double rush hour of gene expression, which I thought was quite funny.”
— Christina Naula31:49
Key Quote
“And my design of a sporozoite is not relevant.”
— Vincent Racaniello41:14
Key Quote
“Are they riding the wave or are they manipulating the wave?”
— Daniel Griffin1:03:12