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Tissue optical clearing technology has been developing rapidly in the past decade due to advances in microscopy equipment and various labeling techniques. Consistent modification of primary methods for optical tissue transparency has allowed observation of the whole mouse body at single-cell resolution or thick tissue slices at the nanoscale level, with the final aim to make intact primate and human brains or thick human brain tissues optically transparent. Optical clearance combined with flexible large-volume tissue labeling technology can not only preserve the anatomical structure but also visualize multiple molecular information from intact samples in situ. It also provides a new strategy for studying complex tissues, which is of great significance for deciphering the functional structure of healthy brains and the mechanisms of neurological pathologies. In this review, we briefly introduce the existing optical clearing technology and discuss its application in deciphering connection and structure, brain development, and brain diseases. Besides, we discuss the standard computational analysis tools for large-scale imaging dataset processing and information extraction. In general, we hope that this review will provide a valuable reference for researchers who intend to use optical clearing technology in studying the brain.

Mung bean (Vigna radiate) sprouts are a popular choice among sprouted vegetables in Asia. Currently, the impact of nitrogen sources on the growth of mung bean sprouts remains poorly understood, and the underlying biological mechanisms responsible for the observed nonlinear growth patterns at different nitrogen levels have yet to be elucidated. In this research, in addition to conventional growth monitoring and quality evaluation, a comparative proteomics method was applied to investigate the molecular mechanisms of mung bean in response to 0, 0.025, 0.05, 0.075, and 0.1% urea concentrations. Our results indicated that mung bean sprout height and yield increased with rising urea concentrations but were suppressed beyond the L3 level (0.075% urea). Nitrate nitrogen and free amino acid content rose steadily with urea levels, whereas protein content, nitrate reductase activity, and nitrite levels followed a peak-then-decline trend, peaking at intermediate concentrations. Differential expression protein analysis was conducted on mung bean sprouts treated with different concentrations of urea, and more differentially expressed proteins participated in the L3 urea concentration. Analysis of common differential proteins among comparison groups showed that the mung bean sprouts enhanced their adaptability to urea stress environments by upregulating chlorophyll a-b binding protein and cationic amino acid transporter and downregulating the levels of glycosyltransferase, L-ascorbic acid, and cytochrome P450. The proteomic analysis uncovered the regulatory mechanisms governing these metabolic pathways, identifying 47 differentially expressed proteins (DEPs) involved in the biosynthesis of proteins, free amino acids, and nitrogen-related metabolites.

Amyloid-β (Aβ) readily misfolds into neurotoxic aggregates, generating high levels of reactive oxygen species (ROS), leading to progressive oxidative damage and ultimately cell death. Therefore, simultaneous inhibition of Aβ aggregation and scavenging of ROS may be a promising therapeutic strategy to alleviate Alzheimer’s disease pathology. Based on the previously developed antibody 1F12 that targets all forms of Aβ 42 , we developed an Aβ 42 and ROS dual-targeting nanocomposite using biodegradable mesoporous silica nanoparticles as carriers to load ultra-small cerium oxide nanocrystals (bMSNs@Ce-1F12). By modifying the brain-targeted rabies virus glycoprotein 29 (RVG29-bMSNs@Ce-1F12), this intelligent nanocomposite can efficiently target brain Aβ-rich regions. Combined with peripheral and central nervous system treatments, RVG29-bMSNs@Ce-1F12 can significantly alleviate AD symptoms by inhibiting Aβ 42 misfolding, accelerating Aβ 42 clearance, and scavenging ROS. Furthermore, this synergistic effect of ROS scavenging and Aβ clearance exhibited by this Aβ 42 and ROS dual-targeted strategy also reduced the burden of hyperphosphorylated tau, alleviated glial cell activation, and ultimately improved cognitive function in APP/PS1 mice. Our findings indicate that RVG29-bMSNs@Ce-1F12 is a promising nanodrug that can facilitate multi-target treatment of AD.

Background Dysbiosis or imbalance of gut microbiota in Alzheimer's disease (AD) affects the production of short-chain fatty acids (SCFAs), whereas exogenous SCFAs supplementation exacerbates brain Aβ burden in APP/PS1 mice. Bifidobacterium is the main producer of SCFAs in the gut flora, but oral administration of Bifidobacterium is ineffective due to strong acids and bile salts in the gastrointestinal tract. Therefore, regulating the levels of SCFAs in the gut is of great significance for AD treatment. Methods We investigated the feasibility of intranasal delivery of MSNs- Bifidobacterium (MSNs-Bi) to the gut and their effect on behavior and brain pathology in APP/PS1 mice. Results Mesoporous silica nanospheres (MSNs) were efficiently immobilized on the surface of Bifidobacterium . After intranasal administration, fluorescence imaging of MSNs-Bi in the abdominal cavity and gastrointestinal tract revealed that intranasally delivered MSNs-Bi could be transported through the brain to the peripheral intestine. Intranasal administration of MSNs-Bi not only inhibited intestinal inflammation and reduced brain Aβ burden but also improved olfactory sensitivity in APP/PS1 mice. Conclusions These findings suggested that restoring the balance of the gut microbiome contributes to ameliorating cognitive impairment in AD, and that intranasal administration of MSNs-Bi may be an effective therapeutic strategy for the prevention of AD and intestinal disease.

Aβ 42 is one of the most extensively studied blood and Cerebrospinal fluid (CSF) biomarkers for the diagnosis of symptomatic and prodromal Alzheimer’s disease (AD). Because of the heterogeneity and transient nature of Aβ 42 oligomers (Aβ 42 Os), the development of technologies for dynamically detecting changes in the blood or CSF levels of Aβ 42 monomers (Aβ 42 Ms) and Aβ 42 Os is essential for the accurate diagnosis of AD. The currently commonly used Aβ 42 ELISA test kits usually mis-detected the elevated Aβ 42 Os, leading to incomplete analysis and underestimation of soluble Aβ 42 , resulting in a comprised performance in AD diagnosis. Herein, we developed a dual-target lateral flow immunoassay (dLFI) using anti-Aβ 42 monoclonal antibodies 1F12 and 2C6 for the rapid and point-of-care detection of Aβ 42 Ms and Aβ 42 Os in blood samples within 30 min for AD diagnosis. By naked eye observation, the visual detection limit of Aβ 42 Ms or/and Aβ 42 Os in dLFI was 154 pg/mL. The test results for dLFI were similar to those observed in the enzyme-linked immunosorbent assay (ELISA). Therefore, this paper-based dLFI provides a practical and rapid method for the on-site detection of two biomarkers in blood or CSF samples without the need for additional expertise or equipment. Graphical Abstract

The ubiquitous pathogen Toxoplasma gondii has a complex lifestyle with different metabolic activities at different stages that are intimately linked to the parasitic environments. Here we identified the eukaryotic regulator of cellular homeostasis AMP-activated protein kinase (AMPK) in Toxoplasma and discovered its role in metabolic programming during parasite’s lytic cycle. The catalytic subunit AMPKα is quickly phosphorylated after the release of intracellular parasites to extracellular environments, driving energy-producing catabolism to power parasite motility and invasion into host cells. Once inside host cells, AMPKα phosphorylation is reduced to basal level to promote a balance between energy production and biomass synthesis, allowing robust parasite replication. AMPKγ depletion abolishes AMPKα phosphorylation and suppresses parasite growth, which can be partially rescued by overexpressing wildtype AMPKα but not the phosphorylation mutants. Thus, through the cyclic reprogramming by AMPK, the parasites’ metabolic needs at each stage are satisfied and the lytic cycle progresses robustly. Efficient metabolic regulation is key for parasite growth. Here, the authors report that Toxoplasma alters its AMPK phosphorylation during the lytic cycle, which reprograms parasite’s metabolism to ensure metabolic needs at different stages are met.

Toxoplasma gondii is an extremely successful parasite infecting one third of the human population and numerous animals. It has a complex life cycle with multiple developmental stages that are key for its transmission and pathogenesis. But how the developmental programs are regulated is largely unknown. Here, we screen putative chromatin remodeling proteins in T. gondii and find that a novel complex containing an evolutionarily conserved ATPase SNF2L is critical for programming the parasite’s development. This complex contains four core proteins and conditional depletion of three of them leads to similar expression changes of developmentally regulated genes, including increased transcription of genes involved in sexual commitment and development. Accordingly, depletion of SNF2L causes merogony and out-budding types of division, which are otherwise only observed at the enteroepithelial stages within definitive hosts where sexual reproduction of the parasite occurs. After being recruited to target regions, SNF2L regulates gene expression by modulating local chromatin accessibility or by recruiting accessory proteins to its binding sites, thus ensuring that the gene expression and reproduction patterns are matched to the life cycle stages. Conditional depletion of SNF2L offers an opportunity to study the unique biology of the parasite during pre-sexual and sexual developments in vitro. The zoonotic parasite Toxoplasma has complex developmental programs to accommodate different lifestyles that are important for parasite transmission and pathogenesis. Here, the authors discover a novel chromatin remodeling complex containing SNF2L in Toxoplasma and report its crucial roles in regulating the parasite’s developmental programs.

Objective This study aimed to investigate the clinical efficacy of arthroscopy-assisted absorbable screw combined with Kirschner wire internal fixation in the treatment of Sanders type III displaced intra-articular calcaneal fractures. Methods Eighty patients diagnosed with Sanders type III displaced intra-articular calcaneal fractures and treated at Dongguan Hospital of Guangzhou University of Chinese Medicine in China from December 2020 to June 2023 were enrolled in this study. According to treatment protocol, these patients were divided into the A group ( n  = 40), which underwent subtalar arthroscopic reduction combined with absorbable screw and Kirschner wire internal fixation, and the H group ( n  = 40), which received hollow screw internal fixation via a modified tarsal sinus incision. Intraoperative metrics, including intraoperative blood loss and operation time, were comparatively analysed. Postoperative functional improvement, including parameters such as fracture healing time, pre- and postoperative Visual Analog Scale (VAS), American Orthopedic Foot and Ankle Society Ankle-Hindfoot Score (AOFAS), Maryland Foot Score (MFS), Tegner scores and radiological parameters such as Böhler’s angle, Gissane’s angle and calcaneus height and width, was also evaluated. The incidence and nature of postoperative complications were analysed. Results (1) No significant differences in intraoperative blood loss, operation time and postoperative fracture healing time were observed between the two groups ( P  > 0.05). (2) Postoperative follow-ups revealed significant improvements in VAS scores, AOFAS ankle–hindfoot scores, MFS scores and Tegner scores in both groups ( P  < 0.05). Compared with the H group, the A group demonstrated significantly superior AOFAS ankle–hindfoot and MFS scores at 3 and 12 months post operation and Tegner scores at 12 months post operation and at the last follow-up ( P  < 0.05). No significant differences in postoperative VAS scores were found between the two groups ( P  > 0.05). (3) Significant postoperative improvements were noted in Böhler’s angle, Gissane’s angle and calcaneal dimensions ( P  < 0.05), with no significant intergroup differences during follow-up ( P  > 0.05). (4) The patients in the A group returned to sports activities earlier (7.23 ± 3.4 months) than those in the H group (9.28 ± 3.99 months). (5) The A group exhibited a lower incidence of postoperative complications, with one case of traumatic arthritis (2.5%, 1/40) compared with four cases of peroneal tendonitis (10%, 4/40) in the H group ( P  < 0.05). Conclusion Arthroscopy-assisted absorbable screw combined with Kirschner wire internal fixation provides effective and satisfactory outcomes in terms of internal fixation, foot function and radiological improvements for Sanders type III displaced intra-articular calcaneal fractures. This approach is associated with a low incidence of postoperative complications and a quick return to sports activities. It may potentially obviate the need for secondary surgery for implant removal. Clinical trial number Not applicable.

The protein phosphatase PP2C plays an important role in plant responses to stress. Therefore, the identification of maize PP2C genes that respond to drought stress is particularly important for the improvement and creation of new drought-resistant assortments of maize. In this study, we identified 102 ZmPP2C genes in maize at the genome-wide level. We analyzed the physicochemical properties of 102 ZmPP2Cs and constructed a phylogenetic tree with Arabidopsis. By analyzing the gene structure, conserved protein motifs, and synteny, the ZmPP2Cs were found to be strongly conserved during evolution. Sixteen core genes involved in drought stress and rewatering were screened using gene co-expression network mapping and expression profiling. The qRT-PCR results showed 16 genes were induced by abscisic acid (ABA), drought, and NaCl treatments. Notably, ZmPP2C15 exhibited a substantial expression difference. Through genetic transformation, we overexpressed ZmPP2C15 and generated the CRISPR/Cas9 knockout maize mutant zmpp2c15. Overexpressing ZmPP2C15 in Arabidopsis under drought stress enhanced growth and survival compared with WT plants. The leaves exhibited heightened superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) activities, elevated proline (Pro) content, and reduced malondialdehyde (MDA) content. Conversely, zmpp2c15 mutant plants displayed severe leaf dryness, curling, and wilting under drought stress. Their leaf activities of SOD, POD, APX, and CAT were lower than those in B104, while MDA was higher. This suggests that ZmPP2C15 positively regulates drought tolerance in maize by affecting the antioxidant enzyme activity and osmoregulatory substance content. Subcellular localization revealed that ZmPP2C15 was localized in the nucleus and cytoplasm. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) experiments demonstrated ZmPP2C15’s interaction with ZmWIN1, ZmADT2, ZmsodC, Zmcab, and ZmLHC2. These findings establish a foundation for understanding maize PP2C gene functions, offering genetic resources and insights for molecular design breeding for drought tolerance.

Toxoplasma gondii infects almost all warm-blooded animals, and metabolic flexibility is deemed critical for its successful parasitism in diverse hosts. Glucose and glutamine are the major carbon sources to support parasite growth. In this study, we found that Toxoplasma is also competent in utilizing lactate and alanine and, thus, exhibits exceptional metabolic versatility. Notably, all these nutrients need to be converted to pyruvate to fuel the lytic cycle, and achieving a continued pyruvate supply is vital to parasite survival and metabolic flexibility. Although pyruvate can be generated by two distinct pyruvate kinases, located in cytosol and apicoplast, respectively, the cytosolic enzyme is the main source of subcellular pyruvate, and cooperative usage of pyruvate among multiple organelles is critical for parasite growth and virulence. These findings expand our current understanding of carbon metabolism in Toxoplasma gondii and related parasites while providing a basis for designing novel antiparasitic interventions. Toxoplasma gondii is a widespread intracellular pathogen infecting humans and a variety of animals. Previous studies have shown that Toxoplasma uses glucose and glutamine as the main carbon sources to support asexual reproduction, but neither nutrient is essential. Such metabolic flexibility may allow it to survive within diverse host cell types. Here, by focusing on the glycolytic enzyme pyruvate kinase (PYK) that converts phosphoenolpyruvate (PEP) into pyruvate, we found that Toxoplasma can also utilize lactate and alanine. We show that catabolism of all indicated carbon sources converges at pyruvate, and maintaining a constant pyruvate supply is critical to parasite growth. Toxoplasma expresses two PYKs: PYK1 in the cytosol and PYK2 in the apicoplast (a chloroplast relict). Genetic deletion of PYK2 did not noticeably affect parasite growth and virulence, which contrasts with the current model of carbon metabolism in the apicoplast. On the other hand, PYK1 was refractory to disruption. Conditional depletion of PYK1 resulted in global alteration of carbon metabolism, amylopectin accumulation, and reduced cellular ATP, leading to severe growth impairment. Notably, the attenuated growth of the PYK1-depleted mutant was partially rescued by lactate or alanine supplementation, and rescue by lactate required lactate dehydrogenase activity to convert it to pyruvate. Moreover, depletion of PYK1 in conjunction with PYK2 ablation led to accentuated loss of apicoplasts and complete growth arrest. Together, our results underline a critical role of pyruvate homeostasis in determining the metabolic flexibility and apicoplast maintenance, and they significantly extend our current understanding of carbon metabolism in T. gondii . IMPORTANCE Toxoplasma gondii infects almost all warm-blooded animals, and metabolic flexibility is deemed critical for its successful parasitism in diverse hosts. Glucose and glutamine are the major carbon sources to support parasite growth. In this study, we found that Toxoplasma is also competent in utilizing lactate and alanine and, thus, exhibits exceptional metabolic versatility. Notably, all these nutrients need to be converted to pyruvate to fuel the lytic cycle, and achieving a continued pyruvate supply is vital to parasite survival and metabolic flexibility. Although pyruvate can be generated by two distinct pyruvate kinases, located in cytosol and apicoplast, respectively, the cytosolic enzyme is the main source of subcellular pyruvate, and cooperative usage of pyruvate among multiple organelles is critical for parasite growth and virulence. These findings expand our current understanding of carbon metabolism in Toxoplasma gondii and related parasites while providing a basis for designing novel antiparasitic interventions.