Analysis of sugar components and identification of SPS genes in citrus fruit development.

Sugar is a primary determinant of citrus fruit flavour, but undergoes varied accumulation processes across different citrus varieties owing to high genetic variability. Sucrose phosphate synthase (SPS), a key enzyme in glucose metabolism, plays a crucial role in this context. Despite its significance, there is limited research on sugar component quality and the expression and regulatory prediction of SPS genes during citrus fruit development. Therefore, we analysed the sugar quality formation process in 'Kiyomi' and 'Succosa', two citrus varieties, and performed a comprehensive genome-wide analysis of citrus CsSPSs. We observed that the accumulation of sugar components significantly differs between the two varieties, with the identification of four CsSPSs in citrus. CsSPS sequences were highly conserved, featuring typical SPS protein domains. Expression analysis revealed a positive correlation between CsSPS expression and sugar accumulation in citrus fruits. However, CsSPS expression displays specificity to different citrus tissues and varieties. Transcriptome co-expression network analysis suggests the involvement of multiple transcription factors in shaping citrus fruit sugar quality through the regulation of CsSPSs. Notably, the expression levels of four CsWRKYs (CsWRKY2, CsWRKY20, CsWRKY28, CsWRKY32), were significantly positively correlated with CsSPSs and CsWRKY20 might can activate sugar accumulation in citrus fruit through CsSPS2. Collectively, we further emphasize the potential importance of CsWRKYs in citrus sugar metabolism, our findings serve as a reference for understanding sugar component formation and predicting CsSPS expression and regulation during citrus fruit development.

Effect of exogenous melatonin on antioxidant properties and fruit softening of 'Fengtang' plum fruit (Prunus salicina Lindl.) during storage at room temperature.

'Fengtang' plums soften quickly and lose flavor after harvest. This study comprehensively evaluated the effect of exogenous melatonin on the fruit quality of 'Fengtang' plums. According to our findings, exogenous melatonin prevented plum fruit from losing water, delayed the decline in firmness, and preserved a high TSS/TA level. Additionally, exogenous melatonin also enhanced the activity of antioxidant enzymes and increased the non-enzymatic antioxidants, thereby further increasing the antioxidant capacity of plum fruit. Notably, exogenous melatonin delayed the degradation of covalent soluble pectin (CSP), cellulose, and hemicellulose, as well as the rise in water-soluble pectin (WSP) concentration and the activity of cell wall degrading enzymes. Further investigation using atomic force microscopy (AFM) revealed that the chain-like structure of ionic-soluble pectin (ISP) and the self-assembly network structures of CSP were depolymerized, and melatonin treatment retarded the depolymerization of pectin structures. Our results showed that exogenous melatonin preserved the postharvest quality of plum fruits by controlling fruit softness and antioxidant capacity during storage.

Intracerebroventricular injection of sclerostin reduced social hierarchy and impaired neuronal dendritic complexity in mice.

An increasing number of studies have demonstrated extensive functional links between bone and the brain. As a novel endocrine organ, bone has received increasing attention for its upregulatory functions in the brain. Sclerostin, a novel bone-derived endocrine molecule, secreted by osteocytes, can inhibit the bone morphogenetic protein (BMP) and wingless/integrated (Wnt) signaling pathways to regulate bone formation, but its effects on the central nervous system and neurosocial behaviors are unknown. This study investigated the effects of intracerebroventricular sclerostin injection on social-emotional behaviors in adult mice. The results showed that acute elevation of sclerostin levels in the brain could induce anxiety-like behaviors and reduce the social hierarchy of mice while reducing the dendritic complexity of pyramidal neurons in the mouse hippocampus. These data suggested that sclerostin may regulate social-emotional behaviors, providing new evidence for the existence of a bone-brain axis, new insights into the regulation of social behaviors by bone-derived endocrine molecules, and a new direction for the study of individual emotional behavior regulation.

Inspiration for the prevention and treatment of neuropsychiatric disorders: New insight from the bone-brain-axis.

Bone is the main supporting structure of the body and the main organ involved in body movement and calcium and phosphorus metabolism. Recent studies have shown that bone is also a potential new endocrine organ that participates in the physiological and pathophysiological processes of the cardiovascular, digestive, and endocrine systems through various bioactive cytokines secreted by bone cells and bone marrow. Bone-derived active cytokines can also directly act on the central nervous system and regulate brain function and individual behavior. The bidirectional regulation of the bone-brain axis has gradually attracted attention in the field of neuroscience. This paper reviews the regulatory effects of bone-derived active cytokines and bone-derived cells on individual brain function and brain diseases, as well as the occurrence and development of related neuropsychiatric diseases. The central regulatory mechanism function is briefly introduced, which will broaden the scope for mechanistic research and help establish prevention and treatment strategies for neuropsychiatric diseases based on the bone-brain axis.

Exogenous microbiota-derived metabolite trimethylamine N-oxide treatment alters social behaviors: Involvement of hippocampal metabolic adaptation.

Increasing evidence indicates that gut microbiota and its metabolites can influence the brain function and the related behaviors. Trimethylamine N-oxide (TMAO), an indirect metabolite of gut microbiota, has been linked to aging, cognitive impairment, and many brain disorders. However, the potential effects of TMAO on social behaviors remain elusive. The present study investigated the effects of early life systemic TMAO exposure and intra-hippocampal TMAO infusion during adulthood on social behaviors in mice. We also analyzed the effects of intra-hippocampus infusion of TMAO during adulthood on levels of metabolites. The results showed that both systemic TMAO exposure in the post-weaning period and intra-hippocampal TMAO infusion during adulthood decreased social rank and reduced sexual preference in adult mice. Data from LC-MS metabolomics analysis showed that intra-hippocampal TMAO infusion induced a total 207 differential metabolites, which belongs to several metabolic or signaling pathways, especially FoxO signaling pathway and retrograde endocannabinoid signaling pathway. These data suggest that TMAO may affect social behaviors by regulating metabolites in the hippocampus, which may provide a new insight into the role of gut microbiota in regulating social behaviors.

Simple weak-acid derivatives of paclitaxel for remote loading into liposomes and improved therapeutic effects.

Liposomes are among the most successful nanocarriers; several products have been marketed, all of which were prepared by active loading methods. However, poorly water-soluble drugs without ionizable groups are usually incorporated into the lipid bi-layer of liposomes by passive loading methods, with serious drug leakage during blood circulation. Furthermore, there have been few improvements in their anti-cancer activity and safety. Herein, we designed and synthesized three weak-acid modified paclitaxel (PTX) derivatives with a one-step reaction for the remote loading of liposomal formulations. By comparison, PTX-succinic acid liposomes (PTX-SA LPs) exhibited the highest encapsulation efficiency (97.2 ± 1.8%) and drug loading (8.84 ± 0.16%); meanwhile, there was almost no change in their particle size or zeta potential within one month. Furthermore, compared with Taxol®, the PTX-SA LPs showed a 4.35-fold prolonged half-time, enhanced tumor accumulation, and an increased maximum tolerated dose (MTD) of more than 30 mg kg-1. As a result, the PTX-SA LPs displayed significantly improved in vivo anti-cancer efficacy in comparison with Taxol®. Therefore, weak-acid modification is proved to be a simple and effective method to achieve remote loading and high encapsulation efficiency of poorly soluble drugs, showing great potential for clinical application.