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The Journal of Experimental Biology Jun 2024Black soldier fly (Hermetia illucens) larvae are used to upcycle biowaste into insect biomass for animal feed. Previous research on black soldier fly has explored the...
Black soldier fly (Hermetia illucens) larvae are used to upcycle biowaste into insect biomass for animal feed. Previous research on black soldier fly has explored the assimilation of dietary fatty acids (FAs), but endogenous FA synthesis and modification remain comparatively unexplored. This study presents a 1H/2H-NMR methodology for measuring lipid synthesis in black soldier fly larvae using diluted deuterated water (2H2O) as a stable isotopic tracer delivered through the feeding media. This approach was validated by measuring 2H incorporation into the larvae's body water and consequent labelling of FA esterified into triacylglycerols. A 5% 2H enrichment in the body water, adequate to label the FA, is achieved after 24 h in a substrate with 10% 2H2O. A standard feeding trial using an invasive macroalgae was designed to test this method, revealing de novo lipogenesis was lower in larvae fed with macroalgae, probably related to the poor nutritional value of the diet.
Topics: Animals; Larva; Seaweed; Deuterium Oxide; Magnetic Resonance Spectroscopy; Animal Feed; Fatty Acids; Lipids; Diptera; Simuliidae; Diet
PubMed: 38916067
DOI: 10.1242/jeb.247941 -
The Journal of Experimental Biology Oct 2024Amphibians are a classical object for physiological studies, and they are of great value for developmental studies owing to their transition from an aquatic larval form...
Amphibians are a classical object for physiological studies, and they are of great value for developmental studies owing to their transition from an aquatic larval form to an adult form with a terrestrial lifestyle. Axolotls (Ambystoma mexicanum) are of special interest for such studies because of their neoteny and facultative pedomorphosis, as in these animals, metamorphosis can be induced and fully controlled in laboratory conditions. It has been suggested that their metamorphosis, associated with gross anatomical changes in the heart, also involves physiological and electrical remodeling of the myocardium. We used whole-cell patch clamp to investigate possible changes caused by metamorphosis in electrical activity and major ionic currents in cardiomyocytes isolated from paedomorphic and metamorphic axolotls. T4-induced metamorphosis caused shortening of atrial and ventricular action potentials (APs), with no changes in resting membrane potential or maximum velocity of AP upstroke, favoring higher heart rate possible in metamorphic animals. Potential-dependent potassium currents in axolotl myocardium were represented by delayed rectifier currents IKr and IKs, and upregulation of IKs caused by metamorphosis probably underlies AP shortening. Metamorphosis was associated with downregulation of inward rectifier current IK1, probably serving to increase the excitability of myocardium in metamorphic animals. Metamorphosis also led to a slight increase in fast sodium current INa with no changes in its steady-state kinetics and to a significant upregulation of ICa in both atrial and ventricular cells, indicating stronger Ca2+ influx for higher cardiac contractility in metamorphic salamanders. Taken together, these changes serve to increase cardiac reserve in metamorphic animals.
Topics: Animals; Metamorphosis, Biological; Ambystoma mexicanum; Myocytes, Cardiac; Action Potentials; Patch-Clamp Techniques; Heart; Myocardium
PubMed: 38916053
DOI: 10.1242/jeb.247712 -
PloS One 2024Clanis bilineata Walker (Lepidoptera: Sphingidae), a burgeoning edible insect, is experiencing rising demand in China and other regions. Despite this interest, larval...
Clanis bilineata Walker (Lepidoptera: Sphingidae), a burgeoning edible insect, is experiencing rising demand in China and other regions. Despite this interest, larval production is currently constrained by the limitations of artificial production technologies, particularly the selection of optimal host plants. This study rigorously evaluated the performance of C. bilineatha larvae on four main host plants: round-leaf soybean, pointed-leaf soybean, black locust, and kudzu. Preference tests demonstrated that the larvae were most attracted to black locust (34.76 ± 4.65%), with subsequent preferences for kudzu (25.00 ± 6.12%), round-leaf soybean (23.17 ± 2.79%), and pointed-leaf soybean (14.02 ± 4.74%). No significant preference differences were noted between round-leaf soybean and either black locust or kudzu. In feeding assays, the larvae exhibited a marked preference for round-leaf soybean (37.36 ± 0.81 g, total feeding amount for larvae), followed by kudzu (37.26 ± 0.82 g), pointed-leaf soybean (35.38 ± 1.31 g), and black locust (28.53 ± 0.81 g). When the larvae were fed on round-leaf soybean, they exhibited significantly higher survival rate (39.33 ± 0.90%), body weight (9.75 ± 0.07 g), total biomass (383.43 ± 7.35 g), pupation rate (87.78 ± 1.73%), and egg production (189.80 ± 1.06 eggs/female) compared to other hosts. These findings uncovered that round-leaf soybean significantly enhances larval performance, suggesting its potential for improving C. bilineata larval production and sustainability in cultivation systems.
Topics: Animals; Larva; Glycine max; Lepidoptera; Female
PubMed: 38913673
DOI: 10.1371/journal.pone.0303017 -
PloS One 2024In Drosophila coordinated proliferation of two neural stem cells, neuroblasts (NB) and neuroepithelial (NE) cells, is pivotal for proper larval brain growth that...
Multiple isoforms of the Activin-like receptor baboon differentially regulate proliferation and conversion behaviors of neuroblasts and neuroepithelial cells in the Drosophila larval brain.
In Drosophila coordinated proliferation of two neural stem cells, neuroblasts (NB) and neuroepithelial (NE) cells, is pivotal for proper larval brain growth that ultimately determines the final size and performance of an adult brain. The larval brain growth displays two phases based on behaviors of NB and NEs: the first one in early larval stages, influenced by nutritional status and the second one in the last larval stage, promoted by ecdysone signaling after critical weight checkpoint. Mutations of the baboon (babo) gene that produces three isoforms (BaboA-C), all acting as type-I receptors of Activin-type transforming growth factor β (TGF-β) signaling, cause a small brain phenotype due to severely reduced proliferation of the neural stem cells. In this study we show that loss of babo function severely affects proliferation of NBs and NEs as well as conversion of NEs from both phases. By analyzing babo-null and newly generated isoform-specific mutants by CRISPR mutagenesis as well as isoform-specific RNAi knockdowns in a cell- and stage-specific manner, our data support differential contributions of the isoforms for these cellular events with BaboA playing the major role. Stage-specific expression of EcR-B1 in the brain is also regulated primarily by BaboA along with function of the other isoforms. Blocking EcR function in both neural stem cells results in a small brain phenotype that is more severe than baboA-knockdown alone. In summary, our study proposes that the Babo-mediated signaling promotes proper behaviors of the neural stem cells in both phases and achieves this by acting upstream of EcR-B1 expression in the second phase.
Topics: Animals; Drosophila Proteins; Larva; Protein Isoforms; Neural Stem Cells; Cell Proliferation; Brain; Neuroepithelial Cells; Drosophila melanogaster; Signal Transduction; Activin Receptors
PubMed: 38913612
DOI: 10.1371/journal.pone.0305696 -
Virulence Dec 2024β-N-acetylglucosaminidase (NagZ), a cytosolic glucosaminidase, plays a pivotal role in peptidoglycan recycling. Previous research demonstrated that NagZ knockout...
β-N-acetylglucosaminidase (NagZ), a cytosolic glucosaminidase, plays a pivotal role in peptidoglycan recycling. Previous research demonstrated that NagZ knockout significantly eradicated AmpC-dependent β-lactam resistance in . However, NagZ's role in the virulence of remains unclear. Our study, incorporating data on mouse and larval mortality rates, inflammation markers, and histopathological examinations, revealed a substantial reduction in the virulence of following NagZ knockout. Transcriptome sequencing uncovered differential gene expression between NagZ knockout and wild-type strains, particularly in nucleotide metabolism pathways. Further investigation demonstrated that NagZ deletion led to a significant increase in cyclic diguanosine monophosphate (c-di-GMP) levels. Additionally, transcriptome sequencing and RT-qPCR confirmed significant differences in the expression of ECL_03795, a gene with an unknown function but speculated to be involved in c-di-GMP metabolism due to its EAL domain known for phosphodiesterase activity. Interestingly, in ECL_03795 knockout strains, a notable reduction in the virulence was observed, and virulence was rescued upon complementation with ECL_03795. Consequently, our study suggests that NagZ's function on virulence is partially mediated through the ECL_03795→c-di-GMP pathway, providing insight into the development of novel therapies and strongly supporting the interest in creating highly efficient NagZ inhibitors.
Topics: Animals; Virulence; Mice; Enterobacter cloacae; Larva; Moths; Acetylglucosaminidase; Cyclic GMP; Enterobacteriaceae Infections; Virulence Factors; Bacterial Proteins; Female; Gene Expression Regulation, Bacterial; Gene Knockout Techniques
PubMed: 38912723
DOI: 10.1080/21505594.2024.2367652 -
Invertebrate Systematics Jun 2024The antlion genera Gatzara and Nepsalus (Myrmeleontidae: Dendroleontinae) inhabit mountain forests and are characterised by camouflaging larvae. Both genera remain...
The antlion genera Gatzara and Nepsalus (Myrmeleontidae: Dendroleontinae) inhabit mountain forests and are characterised by camouflaging larvae. Both genera remain poorly known despite recent findings on systematics and distribution. We report the discovery of new specimens and the previously unknown larvae of the rare species Gatzara jubilaea Navás, 1915, Nepsalus insolitus (Walker, 1860) and N. decorosus (Yang, 1988). These provide new evidence regarding the affinities of these species, and updated knowledge of the distribution, larval morphology and biology. Moreover, a new species of Nepsalus , N. maclachlani Badano, Zheng & Liu, sp. nov. is described from Sri Lanka based on historical museum collections. The discovery of the immature stages of Gatzara shows that the larvae of this genus share the same specialised ecological characteristics and habits as those of Nepsalus but are less morphologically derived. We also reconstruct a molecular phylogeny of this lineage, estimating the divergence time and biogeographical history by adding the new samples. The evolution of the Gatzara + Nepsalus lineage is associated with two major mountain ranges on the southern Tibetan Plateau, i.e. the Himalayas and the Hengduan Mountains. ZooBank: urn:lsid:zoobank.org:pub:68E68211-DFC1-4D98-997B-8A23BA8F9B69.
Topics: Animals; Sri Lanka; Larva; Phylogeny; Species Specificity; Animal Distribution; Life History Traits
PubMed: 38909607
DOI: 10.1071/IS24010 -
Journal of Insect Physiology Jun 2024The dopaminergic system is involved in caste-specific behaviors in eusocial bumble bees. However, little is known about how the caste differences in dopaminergic system...
The dopaminergic system is involved in caste-specific behaviors in eusocial bumble bees. However, little is known about how the caste differences in dopaminergic system are formed during pupal stages in the brains of bumble bees. Thus, we investigated the levels of dopamine-related substances and expression of genes encoding enzymes involved in dopamine synthesis and metabolism, dopamine receptors, and a dopamine transporter in the brain of female Bombus ignitus. The levels of dopamine and dopamine-related substances in the brain were significantly higher in gynes than in workers from the late pupal stage to emergence, but the dynamics were similar between the castes. The relative expression levels of genes encoding enzymes involved in dopamine synthesis (BigTh and BigDdc) and dopamine metabolism (BigNat) increased significantly from pupal stage to emergence, but there were no differences in the relative expression levels of these genes between castes. A similar pattern was seen in the relative expression levels of four dopamine receptor genes (BigDop1, BigDop2, BigDop3, and BigDopEcR) and a dopamine transporter gene (BigDat). Compared with the honey bee Apis mellifera, the caste-specific dopaminergic system in the bumble bee is less differentiated, which might reflect the degree of behavioral specialization in these two species.
PubMed: 38906458
DOI: 10.1016/j.jinsphys.2024.104665 -
Developmental Biology Jun 2024In animals undergoing metamorphosis, the appearance of the nervous system is coincidently transformed by the morphogenesis of neurons. Such morphogenic alterations are...
In animals undergoing metamorphosis, the appearance of the nervous system is coincidently transformed by the morphogenesis of neurons. Such morphogenic alterations are exemplified in three types of intrinsic neurons in the Drosophila memory center. In contrast to the well-characterized remodeling of γ neurons, the morphogenesis of α/β and α'/β' neurons has not been adequately explored. Here, we show that mamo, a BTB-zinc finger transcription factor that acts as a terminal selector for α'/β' neurons, controls the formation of the correct axonal pattern of α'/β' neurons. Intriguingly, specific Mamo isoforms are preferentially expressed in α'/β' neurons to regulate the expression of axon guidance molecule Semaphorin-1a. This action directs proper axon guidance in α'/β' neurons, which is also crucial for wiring of α'/β' neurons with downstream neurons. Taken together, our results provide molecular insights into how neurons establish correct axonal patterns in circuitry assembly during adult memory center construction.
PubMed: 38906235
DOI: 10.1016/j.ydbio.2024.06.010 -
PloS One 2024Anthropogenic pressures threaten biodiversity, necessitating conservation actions founded on robust ecological models. However, prevailing models inadequately capture...
Anthropogenic pressures threaten biodiversity, necessitating conservation actions founded on robust ecological models. However, prevailing models inadequately capture the spatiotemporal variation in environmental pressures faced by species with high mobility or complex life histories, as data are often aggregated across species' life histories or spatial distributions. We highlight the limitations of static models for dynamic species and incorporate life history variation and spatial distributions for species and stressors into a trait-based vulnerability and impact model. We use green sea turtles in the Greater Caribbean Region to demonstrate how vulnerability and anthropogenic impact for a dynamic species change across four life stages. By incorporating life stages into a trait-based vulnerability model, we observed life stage-specific vulnerabilities that were otherwise unnoticed when using an aggregated trait value set. Early life stages were more vulnerable to some stressors, such as inorganic pollution or marine heat waves, and less vulnerable to others, such as bycatch. Incorporating spatial distributions of stressors and life stages revealed impacts differ for each life stage across spatial areas, emphasizing the importance of stage-specific conservation measures. Our approach showcases the importance of incorporating dynamic processes into ecological models and will enable better and more targeted conservation actions for species with complex life histories and high mobility.
Topics: Animals; Turtles; Biodiversity; Conservation of Natural Resources; Caribbean Region; Models, Biological; Life History Traits; Life Cycle Stages; Ecosystem
PubMed: 38905300
DOI: 10.1371/journal.pone.0305950 -
PloS One 2024The dung beetle primarily feeds on the feces of herbivorous animals and play a crucial role in ecological processes like material cycles and soil improvement. This study...
The dung beetle primarily feeds on the feces of herbivorous animals and play a crucial role in ecological processes like material cycles and soil improvement. This study aims to explore the diversity and composition of the gut microbiota of Catharsius molossus (a renowned dung beetle originating from China and introduced to multiple countries for its ecological value) and exploring whether these gut microbes are transmitted vertically across generations. Using 16S rRNA and ITS rRNA gene sequencing techniques, we described the diversity and composition of gut microbes in C. molossus from different localities and different developmental stages (Egg, young larvae and old larvae). We discovered that the diversity of gut microbiota of dung beetles varied obviously among different geographical localities and different developmental stages, and we also discussed the potential influencing factors. Interestingly, the microbial community structure within the brood balls is more similar to male dung beetle than to that of females, which is consistent with the observation that the brood ball is constructed by the male dung beetle, with the female laying egg in it at the final step. This unique breeding method facilitates offspring in inheriting microbial communities from both the mother and the father. Initially, the larvae's gut microbiota closely mirrors that of the parental gift in these brood balls. As larvae grow, significant changes occur in their gut microbiota, including an increase in symbiotic bacteria like Lactococcus and Enterococcus. Analysis of the gut bacteria of adult dung beetles across various localities and different developmental stages identified nine core genera in adults, contributing to 67.80% of the total microbial abundance, and 11 core genera in beetles at different developmental stages, accounting for 49.13% of the total. Notably, seven genera were common between these two core groups. Our results suggest that Parental gifts can play a role in the vertical transmission of microbes, and the abundance of probiotics increases with larval development, supporting the hypothesis that "larval feeding behavior occurs in two stages: larvae first feed on parental gifts to acquire necessary microbes, then enrich symbiotic microbiota through consuming their own feces."
Topics: Animals; Coleoptera; Gastrointestinal Microbiome; Female; Male; Larva; RNA, Ribosomal, 16S; Bacteria; Biodiversity; China; Phylogeny
PubMed: 38905245
DOI: 10.1371/journal.pone.0304908