Current Biology最新文献

Vanhove and colleagues introduce monogenean parasitic flatworms, a species-rich group of ectoparasitic flatworms that are mostly found on the skin, gills, or fins of fish and have a life cycle involving a single host.

Rising temperature extremes during critical reproductive periods threaten the yield of major grain and fruit crops. Flowering plant reproduction depends on the ability of pollen grains to generate a pollen tube, which elongates through the pistil to deliver sperm cells to female gametes for double fertilization. We used tomato as a model fruit crop to determine how high temperature affects the pollen tube growth phase, taking advantage of cultivars noted for fruit production in exceptionally hot growing seasons. We found that exposure to high temperature solely during the pollen tube growth phase limits fruit biomass and seed set more significantly in thermosensitive cultivars than in thermotolerant cultivars. Importantly, we found that pollen tubes from the thermotolerant Tamaulipas cultivar have enhanced growth in vivo and in vitro under high temperature. Analysis of the pollen tube transcriptome's response to high temperature allowed us to define two response modes (enhanced induction of stress responses and higher basal levels of growth pathways repressed by heat stress) associated with reproductive thermotolerance. Importantly, we define key components of the pollen tube stress response, identifying enhanced reactive oxygen species (ROS) homeostasis and pollen tube callose synthesis and deposition as important components of reproductive thermotolerance in Tamaulipas. Our work identifies the pollen tube growth phase as a viable target to enhance reproductive thermotolerance and delineates key pathways that are altered in crop varieties capable of fruiting under high-temperature conditions.

The ability to anticipate tides is critical for a wide range of marine organisms, but this task is complicated by the diversity of tidal patterns on Earth. Previous findings suggest that organisms whose geographic range spans multiple types of tidal cycles can produce distinct patterns of rhythmic behavior that correspond to the tidal cycles they experience. How this behavioral plasticity is achieved, however, is unclear. Here, we show that Parhyale hawaiensis adapts its rhythmic behavior to various naturally occurring tidal regimens through the plastic contribution of its circatidal and circadian clocks. After entrainment to a tidal cycle that deviated only mildly from a regular 12.4 h tidal cycle, animals exhibited strong circatidal rhythms. By contrast, following entrainment to more irregularly spaced tides or to tides that occurred every 24.8 h, a significant fraction of animals instead synchronized to the light/dark (LD) cycle and exhibited circadian behavior, while others showed rhythmic behavior with both circatidal and circadian traits. We also show that the circatidal clock, while able to entrain to various naturally occurring tidal patterns, does not entrain to an unnatural one. We propose that Parhyale hawaiensis's ecological success around the world relies in part on the plastic interactions between the circatidal and circadian clocks, which shape its rhythmic behavior appropriately according to tidal patterns.

Maladaptive decision-making is a hallmark of substance use disorders (SUDs), though how drugs of abuse alter neural representations supporting adaptive behavior remains poorly understood. Past studies show that the orbitofrontal (OFC) and prelimbic (PL) cortices are important for decision-making, tracking both task-relevant and latent information. However, previous studies have focused on how drugs of abuse impact the firing rates of individual units. More work at the ensemble level is necessary to accurately characterize potential drug-induced changes. Using single-unit recordings in rats during a multidimensional decision-making task and then applying population- and ensemble-level analyses, we show that prior use of cocaine altered the strength and structure of task-relevant and latent representations in the OFC, changes relatable to suboptimal decision-making in this and perhaps other settings. These data expand our understanding of the neuropathological underpinnings of maladaptive decision-making in SUDs, potentially enabling enhanced future treatment strategies.

The root system of a plant is essential for plant growth and development because it absorbs nutrients and water from the soil. The root stem cells are maintained and replenished by the quiescent center and are essential for the formation of the specific root structure. In Arabidopsis, the WUSCHEL-RELATED HOMEOBOX 5 (WOX5) plays a key role in regulating root stem cell fate. However, which factor can directly modulate the stability of WOX5 protein remains totally unknown. Here, we report that the peptidase DA1 (LARGE IN CHINESE) interacts with and cleaves WOX5, resulting in the destabilization of WOX5. Genetic analyses support that DA1 acts through WOX5 to regulate root stem cell function. We further demonstrate that cytokinin (CK) signaling induces the accumulation of DA1 protein, thereby decreasing the abundance of WOX5 protein in the root. Consistent with these results, the mutation in DA1 increases the layers of columella stem cells and influences CK-induced differentiation of columella stem cells. Thus, our results reveal a previously unrecognized mechanism by which the cleavage of WOX5 by DA1 connects CK signaling and root stem cell function in Arabidopsis.

Movement is the "enemy of camouflage", but most animals must move to find resources, such as mates, food and shelter. Therefore, strategies that disrupt predator localization or speed perception of moving prey can play a crucial role in prey survival. Shiny or glossy appearances, which are characterised by having a high degree of specular (mirror-like) reflection of incident light¹, can disrupt predator hunting behaviours towards moving prey². Different mechanisms may explain this effect^3,4,5, but no study has attempted to identify the mechanisms that disrupt perception of moving glossy prey by non-human predators. Here, we present moving glossy green or grey targets to jumping spiders (Maratus griseus) and precisely document predator hunting behaviours using high speed videography. Jumping spiders were less precise at tracking glossy targets compared to control targets, suggesting glossiness may disrupt localisation of moving targets. Importantly for prey, jumping spider attack jumps were substantially less accurate towards glossy prey compared to control targets. These results were independent of underlying target colour, suggesting benefits of glossiness may be generalisable to differently coloured glossy animals. Our results indicate that glossiness, when paired with motion, creates an unpredictable target that is difficult for predators to localise, offering insights into the prevalence of dynamically coloured organisms in nature.

The molecular mechanisms underlying evolution of morphological novelties are not well understood, although co-option is often inferred. A new study demonstrates that the partial co-option of the trichome gene regulatory network underlies the evolution of novel projections on Drosophila male genitalia.

Male gametophyte development is highly sensitive to elevated temperatures. A new study identifies potential drivers of reproductive thermoresilience during pollen tube growth by comparing a set of thermotolerant and thermosensitive tomato cultivars.

For over a century, there was a major gap in our understanding of the evolution of the flying Mesozoic reptiles, the pterosaurs, with a major morphological gap between the early forms and the derived pterodactyloids.¹ Recent discoveries have found a cluster of intermediate forms that have the head and neck of the pterodactyloids but the body of the early grade,² yet this still leaves fundamental gaps between these intermediates and both earlier and more derived pterosaurs. Here, we describe a new and large Jurassic pterosaur, Skiphosoura bavarica gen. et sp. nov., preserved in three dimensions, that helps bridge the gap between current intermediate pterosaurs and the pterodactyloids. A new phylogeny shows that there is a general progression of key characteristics of increasing head size, increasing length of neck and wing metacarpal, modification to the fifth toe that supports the rear wing membrane, and gradual reduction in tail length and complexity from earlier pterosaurs into the first pterodactyloids. This also shows a clear evolution of the increasing terrestrial competence of derived pterosaurs. Furthermore, this closes gaps between the intermediates and their ancestors and descendants, and it firmly marks the rhamphorhynchines and ctenochasmatid clades as, respectively, being the closest earliest and latest groups to this succession of transitional forms.