Biology subjects

Diggs, S.

Publications and source records attributed to Diggs, S..

3 recordsLinked to original sources

bioRxiv2026

Temporal synchrony between human odor rhythms and mosquito olfactory preference shapes host attraction

For anthropophilic mosquitoes such as Aedes aegypti, aligning host-seeking with human availability enhances foraging efficiency and reproductive success. Although time of day modulates mosquito activity and olfactory sensitivity, it remains unknown whether human hosts display rhythmic changes in odor cues and whether mosquitoes adjust their sensory responses accordingly. Here, we combine chemical, behavioral, genetic, and transcriptomic approaches to reveal that both mosquitoes and their human hosts in this interaction are temporally synchronized. Gas chromatography-mass spectrometry showed systematic daily shifts in human body odor composition between morning and evening. Correspondingly, mosquitoes prefer host odors that match their own active phase--a time-specific preference abolished in timeless mutants and under constant darkness. Silencing the timeless gene further induced an aversion for the host scent under light-dark conditions. Transcriptomic analysis of mosquito heads and antennae uncovered rhythmic expression of sensory and neuromodulatory genes, driven by both circadian and light-dark cycles and which peaks during mosquitoes active periods, with rhythmic co-expression networks collapsing in timeless knockouts. Together, these results show that mosquito attraction to humans is temporally tuned by the interplay of host odor rhythms and mosquito sensory rhythms, revealing a previously unrecognized form of interspecific temporal synchronization in vector-host interactions.

animal behavior and cognition↗

bioRxiv2025

In extracto cryo-EM reveals eEF2 as a major hibernation factor on 60S and 80S particles

Cryogenic electron microscopy (cryo-EM) made impressive progress in resolving cellular macromolecules and their detailed interactions. Single-particle cryo-EM traditionally relies on purified macromolecules and lacks the complexity of cellular environments, whereas in situ cryo-EM or cryo-ET require extensive sample preparation and data acquisition, presenting challenges in achieving high resolution. We describe cryo-EM of cellular lysates--in extracto cryo-EM--allowing the flexibility and high-resolution of cryo-EM in the context of cellular components. High-resolution 2D template matching (2DTM) yields [~]2.2 [A] maps of the mammalian translational apparatus. Elongating ribosome abundances in primate cell lines (MCF-7 and BSC-1) and rabbit reticulocyte lysates range from [~]70% to [~]10%, reflecting translational stress responses. Non-translating (hibernating) ribosomes carrying no mRNA, feature numerous proteins shielding ribosomal functional centers. Elongation factor 2 (eEF2) is the most abundant hibernation factor bound to >95% of ribosomes and, unexpectedly, to 60S subunits. eEF2*GDP is stabilized by interactions with the sarcin-ricin loop and protein uL14. Hibernating ribosomes also feature LARP1 involved in initiation and mTOR signaling; eIF5A implicated in elongation and termination; and other factors, exposing the variety of hibernation scenarios. Our work underscores the efficiency and potential of in extracto cryo-EM to discover native cellular complexes and mechanisms at near-atomic resolution.

molecular biology↗

bioRxiv2019

An amino-terminal threonine/serine motif is necessary for activity of the Crp/Fnr homolog, MrpC, and for Myxococcus xanthus developmental robustness

The Crp/Fnr family of transcriptional regulators play central roles in transcriptional control of diverse physiological responses. Activation of individual family members is controlled by a surprising diversity of mechanisms tuned to the particular physiological responses or lifestyles that they regulate. MrpC is a Crp/Fnr homolog that plays an essential role in controlling the Myxococcus xanthus developmental program. A long-standing model proposed that MrpC activity is controlled by the Pkn8/Pkn14 serine/threonine kinase cascade which phosphorylates MrpC on threonine residue(s) located in its extreme amino terminus. In this study, we demonstrate that a stretch of consecutive threonine and serine residues, T21 T22 S23 S24, is necessary for MrpC activity by promoting efficient DNA binding. Mass spectrometry analysis indicated the TTSS motif is not directly phosphorylated by Pkn14 in vitro but is necessary for efficient Pkn14-dependent phosphorylation on several residues in the remainder of the protein. Pkn8 and Pkn14 kinase activities do not play obvious roles in controlling MrpC activity in wild type M. xanthus under laboratory conditions, but likely modulate MrpC DNA binding in response to unknown environmental conditions. Interestingly, mutational analysis of the TTSS motif caused non-robust developmental phenotypes, revealing that MrpC plays a role in developmental buffering.

microbiology↗