Dongdong Zhang | Search PubMed

PubMed2026

Biogeographic patterns and metabolic potential of chemoautotrophic communities in cold seep sediments across subarctic to tropical regions.

Cold seeps are hotspots of chemoautotrophic primary production, yet how chemoautotrophic community structure and dark carbon fixation (DCF) vary across climatic regions remains unclear. We combined incubation experiments and metagenomics to compare chemoautotrophic communities in cold seep sediments across northwestern Pacific marginal seas, from the subarctic Okhotsk Sea to the tropical South China Sea. Incubation experiments demonstrated higher DCF rates in tropical (1.20 μg C g-1 day-1) than subarctic (0.35 μg C g-1 day-1) sediments (p = 0.002). Analyses of 133 cold seep sediment metagenomes (26 in this study and 107 from NCBI, spanning 0-240 cmbsf) revealed that subarctic chemoautotrophs were dominated by Chloroflexota, Asgardarchaeota, Campylobacterota, and Thermoproteota, whereas tropical chemoautotrophs were dominated by Pseudomonadota and Asgardarchaeota, with higher alpha diversity and integrated co-occurrence networks observed in tropical sediments. Representative genes of the Calvin-Benson-Bassham (CBB) cycle, the 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) cycle, and the 3-hydroxypropionate (3HP) bicycle were enriched in tropical sediments, whereas reductive tricarboxylic acid (rTCA) cycle and Wood-Ljungdahl (WL) pathway genes predominated in subarctic sediments. Genome-resolved analysis showed that CBB cycle potential was concentrated in Pseudomonadota in tropical sediments and in Asgardarchaeota in subarctic sediments, and was most strongly correlated with nitrogen metabolism genes, whereas rTCA cycle potential was concentrated in Campylobacterota across both sediments, coupled strongly to sulfur metabolism. Depth profiling revealed surface communities dominated by Campylobacteria using rTCA cycle in subarctic sediments, and Alphaproteobacteria and Gammaproteobacteria using CBB cycle in tropical sediments, whereas the WL pathway predominated in Dehalococcoidia and Lokiarchaeia in the deeper layers of both regions. This study provides a comparative framework for chemoautotrophic biogeography across climatically distinct seeps.

Climate zones↗

PubMed2026

Neurovascular coupling in the basolateral amygdala modulates negative emotions.

Emotion induces changes in regional cerebral blood flow, a manifestation of neurovascular coupling (NVC). However, whether NVC provides feedback to actively modulate emotion remains unexplored. Here, we demonstrate that NVC actively and bidirectionally modulates stress-induced negative emotions. We established bidirectional manipulations of NVC in freely moving mice by employing integrated pharmacological, genetic, and arteriolar optogenetic approaches. Our results showed that both systemic and region-specific NVC deficiencies in the basolateral amygdala (BLA) heightened emotional responses when mice transitioned from a safe, familiar environment to anxiogenic environments and that local restoration of NVC in the BLA normalized these responses. Mechanistically, NVC dysfunction impaired the capacity of BLA neuronal scaling during state transitions, manifesting as a characteristic biphasic pattern of c-Fos topology. NVC-deficient animals aberrantly adopted high-stress configurations under mild stress but regressed to low-stress templates during high-demand survival threats, thereby compromising defensive sustainability. Notably, the genetic NVC-enhancement model counteracted NVC impairments caused by chronic stress, thereby alleviating stress-driven emotional distress. These findings establish NVC in the BLA as an allostatic program that fine-tunes neural circuit activity during emotional responses, with implications for understanding and treating emotional disorders.

Animals↗