Biology Open最新文献

Parasitoid wasps exert strong selective pressure on their hosts, driving the evolution of diverse defense strategies. Drosophila, a widely studied model organism, hosts a wide range of parasites, including parasitoid wasps, and has evolved immune and behavioral mechanisms to mitigate the risk of parasitization. These defenses range from avoidance and evasion to post-infection immune responses, such as melanotic encapsulation. In response, parasitoid wasps have developed countermeasures, contributing to an ongoing arms race between host and parasite. This article reviews the anti-parasitoid behaviors of Drosophila, focusing on their role in reducing parasitization and enhancing host survival and fitness. It also explores the molecular and neuronal circuit mechanisms that underlie these behaviors, using Drosophila as an ecologically relevant model for studying host-parasitoid interactions. Furthermore, the article discusses the potential applications of these findings in biological pest control and highlights key unresolved questions in the field.

The 20th instalment of the Progressive Palaeontology conference was held from 17th-20th of June 2024 at the University of Bristol, UK. Progressive Palaeontology gives postgraduate students experience of presenting at a conference to an audience of their peers, and the opportunity to form networks with researchers at their career stage. The conference was organised on behalf of the Palaeontological Association by Hady George, Thomas Farrell, James R. G. Rawson, Isaura Aguilar-Pedrayes, Benton Walters and Kirsten E. Flett, all of whom are postgraduate students in the Bristol Palaeobiology group. The meeting was a great success, featuring a high standard of research presentations on a wide range of topics, and inclusive and educational events hosted throughout the conference.

During neurogenesis, excessive numbers of neurons are produced in most regions of the central and peripheral nervous systems. Nonessential neurons are eliminated by apoptosis, or programmed cell death. This has been most thoroughly characterized in the peripheral nervous system (PNS) where targets of innervation play a key role in this process. As maturing neurons project axons towards their targets of innervation, they become dependent upon these targets for survival. Survival factors, also called neurotrophic factors, are produced by targets, inhibit apoptosis cascades, and promote further growth and differentiation. Because neurotrophic factors are limited, as is target size, neurons that do not correctly and efficiently innervate targets undergo apoptosis ( Levi-Montalcini, 1987; Davies, 1996). Thus, excessive neurogenesis acts to ensure that sufficient numbers of neurons are produced during development. In the superior cervical ganglion (SCG), this process of neurogenesis and subsequent apoptosis is reported to be complete by postnatal day 3-4 (P3-P4) in mice. Surprisingly, we observed significant numbers of apoptotic neurons out to P14, and neurogenesis was still present at P14 as well. In both the SCG and geniculate ganglion (GG), postnatal neurogenesis was dependent on apoptosis because little or no postnatal neurogenesis was observed in Bax-/- mice, in which apoptosis is eliminated. These results indicate that both neurogenesis and apoptosis continue to occur well after birth in peripheral ganglia, and that neurogenesis depends on apoptosis, suggesting that neurogenesis continues postnatally to replace neurons that are eliminated during synaptic refinement.

Saccharomyces cerevisiae is a powerful model for aging research due to its short lifespan and genetic malleability. Microfluidic devices offer an attractive approach enabling rapid monitoring of hundreds of cells during their entire replicative lifespan (RLS). Yet, key operational issues such as contaminations, cell loss, and cell-aggregates-dependent flow obstruction can hinder RLS experiments. We report the development of a microfluidic device configuration that effectively prevents flow blockage. We conducted comprehensive performance characterization, evaluating trapping efficiency, cell retention, budding orientation, and cell aggregate formation. The optimized device successfully supported long-term culturing and reliable RLS measurements of budding yeast strains. For accurate lifespan determination, a detailed workflow is provided that includes device fabrication, live microscopy setup, and characterization of cell age distribution. This work describes an accessible and reliable microfluidic device for yeast RLS studies, promoting further exploration in aging research.

Exosomes are small extracellular vesicles (sEVs) secreted via multivesicular bodies (MVBs)/late endosomes and mediators of cell-cell communication. We previously reported a novel post-translational modification by ubiquitin-like 3 (UBL3). UBL3 is localized in MVBs and the plasma membrane and released outside as sEVs, including exosomes. Approximately 60% of proteins sorted in sEVs are affected by UBL3 and localized in various organelles, the plasma membrane, and the cytosol, suggesting that its dynamic movement in the cell before entering the MVBs. To examine the intracellular dynamics of UBL3, we constructed a sophisticated visualization system via fusing fluorescent timers that changed from blue to red form over time with UBL3 and by its expression under Tet-on regulation. Intriguingly, we found that after synthesis, UBL3 was initially distributed within the cytosol. Subsequently, UBL3 was localized to MVBs and the plasma membrane and finally showed predominant accumulation in MVBs. Furthermore, by super-resolution microscopy analysis, UBL3 was found to be associated with one of its substrates, α-tubulin, in the cytosol, and the complex was subsequently transported to MVBs. This spatiotemporal visualization system for UBL3 will form a basis for further studies to elucidate when and where UBL3 associates with its substrates/binding proteins before localization in MVBs.

Reproduction requires high amounts of energy, and challenging environments during breeding can force parents to prioritize their current reproductive bout over self-maintenance or vice versa. However, little is known about how common stressors, such as food restriction, can influence these trade-offs during breeding, and the physiological mechanisms for these trade-off decisions. In this study, adult zebra finches (Taeniopygia castanotis) were subjected to a control diet (ad libitum) or a 40% food restriction while raising nestlings and fledglings, and we measured body mass, furculum fat, plasma corticosterone (CORT) and blood glucose levels of the parents at the time of pairing, when their offspring fledged, and when their offspring reached nutritional independence. We also measured body mass and growth rate in the offspring from hatching until the end of the treatment period. Food-restricted parents had lower body mass when their offspring fledged and reached nutritional independence and higher baseline CORT when their offspring fledged compared to controls. Offspring did not differ in body mass or growth rate between treatment groups. However, there was no effect of food restriction on parents' furculum fat, baseline glucose, the adrenocortical response, or the glucose response. Furthermore, path analysis results suggest that alterations in baseline glucose is the primary driver of changes in body mass in parents and offspring brood mass. Taken together, these results suggest that food restriction during chick rearing in a short-lived passerine drives parents to prioritize their current reproductive bout over self-maintenance, and glucose could potentially be a mechanism for diverting energy toward parental effort.

Routine histochemical techniques are capable of producing vast amount of information from diverse sample types, but these techniques are limited in their ability to generate 3D information. Autofluorescence imaging can be used to analyse samples in 3D but it suffers from weak/low signal intensities. Here, we describe a simple chemical treatment with glutaraldehyde to enhance autofluorescence for 3D fluorescence imaging and to generate detailed morphological images on whole-mount samples. This methodology is straightforward and cost-effective to implement, suitable for a wide range of organisms and sample types. Furthermore, it can be readily integrated with standard confocal and fluorescence microscopes for analysis. This approach has the potential to facilitate the analysis of biological 3D structures and research in developmental biology, including studies on model and non-model organisms.

Insects exhibit a remarkable ability to interact with inanimate objects to facilitate essential behaviors such as foraging, reproduction, shelter building, and defense. In this study, we assessed whether Drosophila interacted with inanimate objects when they were suspended on their wings and provided with a thermocol ball (foam ball). Drosophila indeed exhibited ball rolling behavior. We further examined the sexual dimorphism in this ball rolling-associated locomotor behavior. We carried out a ball rolling assay using 3-day-old male and female w1118 flies and measured the duration for which the flies could roll the ball without dropping it within a 10 min period. The ball was returned to the flies whenever they dropped it, and we calculated the number of times the ball was dropped within the 10 min duration. Females exhibited a longer ball holding duration than males. We also observed a decrease in ball holding duration and an increase in the number of times the ball was dropped by 15-day-old male and female flies than their younger counterparts. These results suggest sexual dimorphism and age-dependent alterations in Drosophila ball rolling-associated locomotor behavior.

Drosophila oogenesis has long been an important model for understanding myriad cellular processes controlling development, RNA biology and patterning. Flies are easily fed drugs to disrupt various molecular pathways. However, this is often done under poor nutrient conditions that adversely affect oogenesis, thus making analysis challenging. Cycloheximide is a widely used compound that binds to and stalls the ribosome, therefore reducing protein synthesis. As egg production is a highly nutrient-dependent process, we developed a method to feed female Drosophila a rich diet of yeast paste supplemented with cycloheximide to better determine the effect of cycloheximide treatment on oogenesis. We found that flies readily consumed cycloheximide-supplemented yeast paste. Males and females had reduced lifespans when maintained on cycloheximide, with males exhibiting a dose-dependent decrease. Although females did not exhibit decreased egg laying, their ovaries were smaller and the number of progeny reduced, indicating substandard egg quality. Finally, females fed cycloheximide had disrupted oogenesis, with smaller ovaries, missing ovariole stages, and an increase in apoptotic follicles. Together, these data support that reduced protein synthesis adversely affects oogenesis with a rich diet that provides optimal nutrient conditions. In addition, this method could be used more broadly to test the effect of other drugs on Drosophila oogenesis without the confounding effects caused by poor nutrition.

Benthic fish, such as the round goby (Neogobius melanostomus Pallas, 1814) tend to swim near the bottom, especially at increased water velocities. To test whether these fish have a hydraulic advantage from swimming near the bottom and how the substrate affects the forces experienced, we measured the hydraulic forces experienced by preserved fish in a flow channel. The fish were tested 5.0 mm above the bottom at smooth and rough surface, and in the water column (10.0 cm elevation) above smooth and rough surface at 0.95 m/s water velocity. No significant effect among the mean hydraulic forces was observed between both fish positions, whereas the mean hydraulic forces in the water column were significantly higher (P<0.05) above the rough surface (mean 0.077 N±0.025 s.d.) than above the smooth surface (mean 0.068 N±0.021 s.d.). A convolutional neural network (CNN) predicted the column smooth treatment was the most characteristic force data time series (mean F1=0.88±0.03 s.d.). We conclude that the body posture and body movements of the fish are more relevant for the hydraulic forces experienced by the fish than the vertical position in the water column. Further factors explaining the affinity to swimming near the bottom are discussed.