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Honeybees are highly social insects with a rich behavioral repertoire and are a versatile model for neurobiological research. Their gut microbiota comprises a limited number of host-restricted bacterial phylotypes that are important for honeybee health. However, it remains unclear how specific gut members affect honeybee behaviors. Here, we find that antibiotic exposure disturbs the gut community and influences honeybee phenotypes under field conditions. Using laboratory-generated gnotobiotic bees, we show that a normal gut microbiota is required for olfactory learning and memory abilities. Brain transcriptomic profiling reveals distinct brain gene expression patterns between microbiota-free and conventional bees. Subsequent metabolomic analyses of both hemolymph and gut samples show that the microbiota mainly regulates tryptophan metabolism. Our results indicate that host-specific Lactobacillus strains promote memory behavior by transforming tryptophan to indole derivatives that activate the host aryl hydrocarbon receptor. Our findings highlight the contributions of specific gut members to honeybee neurological processes, thus providing a promising model to understand host-microbe interactions. Eusocial honeybee is a versatile model for neurobiological research. Here, the authors established a link between honeybee gut Lactobacillus in bee learning and memory ability via indole derivatives that activate host’s aryl hydrocarbon receptor.

Nitrogen (N) plays a vital role in photosynthesis and crop productivity. Maize plants may be able to increase physiological N utilization efficiency (NUtE) under low-N stress by increasing photosynthetic rate (P n) per unit leaf N, that is, photosynthetic N-use efficiency (PNUE). In this study, we analyzed the relationship between PNUE and N allocation in maize ear-leaves during the grain-filling stage under low N (no N application) and high N (180 kg N ha(-1)) in a 2-year field experiment. Under low N, grain yield decreased while NUtE increased. Low-N treatment reduced the specific N content of ear leaves by 38% without significant influencing P n, thereby increasing PNUE by 54%. Under low-N stress, maize plants tended to invest relatively more N into bioenergetics to sustain electron transport. In contrast, N allocated to chlorophyll and light-harvesting proteins was reduced to control excess electron production. Soluble proteins were reduced to shrink the N storage reservoir. We conclude that optimization of N allocation within leaves is a key adaptive mechanism to maximize P n and crop productivity when N is limited during the grain-filling stage in maize under low-N conditions.

Haematopoietic stem cells (HSCs) are derived early from embryonic precursors, such as haemogenic endothelial cells and pre-haematopoietic stem cells (pre-HSCs), the molecular identity of which still remains elusive. Here we use potent surface markers to capture the nascent pre-HSCs at high purity, as rigorously validated by single-cell-initiated serial transplantation. Then we apply single-cell RNA sequencing to analyse endothelial cells, CD45 − and CD45 + pre-HSCs in the aorta–gonad–mesonephros region, and HSCs in fetal liver. Pre-HSCs show unique features in transcriptional machinery, arterial signature, metabolism state, signalling pathway, and transcription factor network. Functionally, activation of mechanistic targets of rapamycin (mTOR) is shown to be indispensable for the emergence of HSCs but not haematopoietic progenitors. Transcriptome data-based functional analysis reveals remarkable heterogeneity in cell-cycle status of pre-HSCs. Finally, the core molecular signature of pre-HSCs is identified. Collectively, our work paves the way for dissection of complex molecular mechanisms regulating stepwise generation of HSCs in vivo , informing future efforts to engineer HSCs for clinical applications. Successful identification of mouse embryonic pre-haematopoietic stem cells at single-cell resolution. Haematopoietic stem cell formation dissected Fuchou Tang and colleagues have isolated the earliest haematopoietic stem cell (HSC) precursors — rare CD45-negative pre-HSCs — from developing mouse embryos using a combination of surface marker expression and single-cell-based transplantation assays, assessing blood-forming capacity. Single-cell RNA-seq was used to analyse the transcriptomes for five types of cells related to HSC formation, revealing a role for mTOR activation in the emergence of HSCs but not haematopoietic progenitors.

Background Honey bee gut microbiota transmitted via social interactions are beneficial to the host health. Although the microbial community is relatively stable, individual variations and high strain-level diversity have been detected across honey bees. Although the bee gut microbiota structure is influenced by environmental factors, the heritability of the gut members and the contribution of the host genetics remains elusive. Considering bees within a colony are not readily genetically identical due to the polyandry of the queen, we hypothesize that the microbiota structure can be shaped by host genetics. Results We used shotgun metagenomics to simultaneously profile the microbiota and host genotypes of bees from hives of four different subspecies. Gut composition is more distant between genetically different bees at both phylotype- and “sequence-discrete population” levels. We then performed a successive passaging experiment within colonies of hybrid bees generated by artificial insemination, which revealed that the microbial composition dramatically shifts across batches of bees during the social transmission. Specifically, different strains from the phylotype of Snodgrassella alvi are preferentially selected by genetically varied hosts, and strains from different hosts show a remarkably biased distribution of single-nucleotide polymorphism in the Type IV pili loci. Genome-wide association analysis identified that the relative abundance of a cluster of Bifidobacterium strains is associated with the host glutamate receptor gene specifically expressed in the bee brain. Finally, mono-colonization of Bifidobacterium with a specific polysaccharide utilization locus impacts the alternative splicing of the gluR-B gene, which is associated with an increased GABA level in the brain. Conclusions Our results indicated that host genetics influence the bee gut composition and suggest a gut-brain connection implicated in the gut bacterial strain preference. Honey bees have been used extensively as a model organism for social behaviors, genetics, and the gut microbiome. Further identification of host genetic function as a shaping force of microbial structure will advance our understanding of the host-microbe interactions. 45gpjtUuBYRAxeW78Mk2MG Video abstract

The regulation of reproductive division of labor in eusocial insects is pivotal for the evolution and maintenance of social organization. In Bombus terrestris, dominance hierarchies emerge among orphan workers through repeated agonistic interactions, forming distinct behavioral ranks. To explore the neural basis of this process, we combined behavioral assays with single-nucleus RNA sequencing to profile brain-wide gene expression across α-, β-, and γ-bumblebee workers. Our analyses revealed pronounced transcriptional divergence among Kenyon cells, which exhibited enrichment in synaptic, insulin, and MAPK signaling pathways. Among the neuropeptides examined, Neuroparsin-A was markedly upregulated in the Kenyon cells and glial cells of dominant workers, while its receptor, OR1, showed strong expression within Kenyon populations, suggesting a conserved neuropeptide–receptor axis in social Hymenoptera. Gene regulatory network inference further identified ecdysone-responsive transcription factors, including br, Eip74EF, Hr38, Hr3 and Hr4, as key regulators linked to neural plasticity and behavioral differentiation. Together, our findings uncover a neuroendocrine mechanism in which Neuroparsin-A signaling coordinates brain transcriptional programs associated with dominance hierarchy formation in queenless bumblebee societies, offering new insights into the molecular underpinnings of eusocial behavior.

Copine proteins are highly conserved and ubiquitously found in eukaryotes, and their indispensable roles in different species were proposed. However, their exact function remains unclear. The phytohormone brassinosteroids (BRs) play vital roles in plant growth, development and environmental responses. A key event in effective BR signaling is the formation of functional BRI1-SERK receptor complex and subsequent transphosphorylation upon ligand binding. Here, we demonstrate that BONZAI (BON) proteins, which are plasma membrane-associated copine proteins, are critical components of BR signaling in both the monocot maize and the dicot Arabidopsis. Biochemical and molecular analyses reveal that BON proteins directly interact with SERK kinases, thereby ensuring effective BRI1-SERK interaction and transphosphorylation. This study advances the knowledge on BR signaling and provides an important target for optimizing valuable agronomic traits, it also opens a way to study steroid hormone signaling and copine proteins of eukaryotes in a broader perspective. Brassinosteroids play vital role in plant growth and development. Here, the authors demonstrate that the plasma membrane-associated copine proteins are new components required for the receptor complex functioning in BR signaling in maize and Arabidopsis.

Nitrogen (N) is one of the most important essential macro-elements for plant growth and development, and nitrate represents the most abundant inorganic form of N in soils. The nitrate uptake and assimilation processes are finely tuned according to the available nitrate in the surroundings as well as by the internal finely coordinated signaling pathways. The NIN-like proteins (NLPs) harbor both RWP-RK, and Phox and Bem1 (PB1) domains, and they belong to the well-characterized plant-specific RWP-RK transcription factor gene family. NLPs are known to be involved in the nitrate signaling pathway by activating downstream target genes, and thus they are implicated in the primary nitrate response in the nucleus via their RWP-RK domains. The PB1 domain is a ubiquitous protein–protein interaction domain and it comprises another regulatory layer for NLPs via the protein interactions within NLPs or with other essential components. Recently, Ca2+–Ca2+ sensor protein kinase–NLP signaling cascades have been identified and they allow NLPs to have central roles in mediating the nitrate signaling pathway. NLPs play essential roles in many aspects of plant growth and development via the finely tuned nitrate signaling pathway. Furthermore, recent studies have highlighted the emerging roles played by NLPs in the N starvation response, nodule formation in legumes, N and P interactions, and root cap release in higher plants. In this review, we consider recent advances in the identification, evolution, molecular characteristics, and functions of the NLP gene family in plant growth and development.

Background Polycystic ovary syndrome (PCOS) is the main cause of anovulatory infertility in women of reproductive age, and low-grade chronic inflammation plays a key role in the occurrence and development of PCOS. However, obesity, as a likely confounding factor, can affect the inflammatory state of PCOS patients. Objective The aim of this study was to comprehensively investigate intra-ovarian inflammatory states and their impact on embryo quality in PCOS patients with a normal BMI undergoing IVF treatment. Methods DIA-mass spectrometry-based proteomics and bioinformatic analysis were combined to comprehensively profile the protein expression of granulosa cells (GCs) from 5 normal-BMI PCOS patients and 5 controls. Thirty-four cytokines were further systematically detected in follicular fluid (FF) from 32 age- and BMI-matched normal-BMI patients using Luminex liquid chip suspension technology. Next, the differentially expressed cytokines were evaluated by enzyme-linked immunosorbent assay (ELISA) in 24 newly recruited subjects, and the relationship between these cytokines and embryo quality in PCOS patients was analysed. Finally, these cytokine levels were compared and evaluated in PCOS patients with different androgen levels. Results Proteomic analysis showed that the suppression of substance metabolism and steroid biosynthesis, more interestingly, resulted in an enhanced immune and inflammatory response in the GCs of normal-BMI PCOS patients and prompted the involvement of cytokines in this process. Luminex analysis further showed that FF macrophage inflammatory protein-1 beta (MIP-1β) and stromal cell-derived factor-1 alpha (SDF-1α) levels were significantly increased in normal-BMI PCOS patients compared to controls ( P  = 0.005; P  = 0.035, respectively), and the ELISA results were consistent with these findings. Besides, FF MIP-1β showed an inverse correlation with the number of D3 good-quality embryos and the good-quality blastocyst rate in patients with PCOS ( P  = 0.006; P  = 0.003, respectively), which remained significant after correction for multiple comparisons. Moreover, SDF-1α levels had no relationship with embryo development in PCOS patients. Additionally, SDF-1α levels were significantly lower in PCOS patients with high androgen levels than in controls ( P  = 0.031). Conclusions Local ovarian inflammation was present in normal-BMI PCOS patients, affecting follicular development, and FF MIP-1β may be a potential biomarker associated with embryo quality in normal-BMI PCOS patients. Graphical abstract

Background Fertilization failure after intracytoplasmic sperm injection continues to affect couples and the etiology is not well-understood. Case presentation We characterized a couple with 2-year history of primary unexplained infertility. Three different assisted reproduction attempts (IVF + rescue ICSI, ICSI and ICSI-AOA) showed repeated fertilization failure for MII oocyte retrieval after controlled ovarian hyperstimulation. After whole-exome sequencing and sanger sequencing of the couple and their family members, variant pathogenicity was assessed using SIFT, PolyPhen2, Mutation Taster, and Human Splicing Finder software. We identified novel compound heterozygous mutations, c.1535 + 3A > G and c.946C > T (p. Leu316Phe), in WEE2 in the female proband. Trios analysis of the variations revealed an autosomal recessive pattern. c.1535 + 3A > G in WEE2 was predicted to break the wild-type donor site and affect splicing, and the missense mutation c.946C > T (p. Leu316Phe) of WEE2 was predicted to be pathogenic. Conclusion A novel compound heterozygous mutation in WEE2 was identified in an infertile female who experienced repeated fertilization failure even after ICSI-AOA. These novel mutations in WEE2 provided genetic evidence for fertilization failure.

Background Lodging is one of the major factors that affect mechanical harvesting and decreases yield and quality of maize. Exploring quantitative trait loci (QTL) or genes underlying lodging resistance is vital for molecular breeding of lodging-resistant maize varieties. Specially, root lodging resistance (RLR) QTLs or genes are rarely reported. Results In this study, to explore the QTLs underlying root lodging resistance, we generated a F 2 population of CIMBL74 and CIMBL145 that have contrastive difference of root architecture and lodging resistance. We performed BSR-seq analysis of the populations and 8 QTLs were identified. Among them, qRLR1 , qRLR4 , qRLR5 and qRLR6 were further confirmed by chromosomal region-based association study (CRAS) and/or linkage mapping. Based on the integrated analysis, 40 and 266 candidate genes, including root development- and cell wall-related genes, were identified in qRLR4 and qRLR6 , respectively. Among them, the ZmNRT5 (encoding a nitrate transporter) located in qRLR6 was identified as a strong candidate gene based on candidate gene association analysis and haplotype analysis. Moreover, the expression level of ZmNRT5 in CIMBL74 was significantly lower than in CIMBL145. Conclusion This study provides valuable QTLs and candidate genes for maize improvement toward enhanced root lodging resistance.