Nanoengineering Carboxysome Shells for Protein Cages with Programmable Cargo Targeting.

Protein nanocages have emerged as promising candidates for enzyme immobilization and cargo delivery in biotechnology and nanotechnology. Carboxysomes are natural proteinaceous organelles in cyanobacteria and proteobacteria and have exhibited great potential in creating versatile nanocages for a wide range of applications given their intrinsic characteristics of self-assembly, cargo encapsulation, permeability, and modularity. However, how to program intact carboxysome shells with specific docking sites for tunable and efficient cargo loading is a key question in the rational design and engineering of carboxysome-based nanostructures. Here, we generate a range of synthetically engineered nanocages with site-directed cargo loading based on an α-carboxysome shell in conjunction with SpyTag/SpyCatcher and Coiled-coil protein coupling systems. The systematic analysis demonstrates that the cargo-docking sites and capacities of the carboxysome shell-based protein nanocages could be precisely modulated by selecting specific anchoring systems and shell protein domains. Our study provides insights into the encapsulation principles of the α-carboxysome and establishes a solid foundation for the bioengineering and manipulation of nanostructures capable of capturing cargos and molecules with exceptional efficiency and programmability, thereby enabling applications in catalysis, delivery, and medicine.

Humic acid chelated selenium is suitable for wheat biofortification.

BACKGROUND: Selenium rich bread is a good carrier of selenium, but the inorganic selenium used in the actual production process is toxic. It is necessary to develop a new green bread production technology. The extraction and utilization of humic acid chelated selenium from selenium-rich soil is beneficial for reducing resource waste and pollution without destroying the soil ecosystem in selenium-deficient areas. Sodium selenite and nanoselenium were selected as controls because they are commonly used as selenium agronomic enhancers in production. RESULTS: Humic acid chelated selenium can be absorbed and accumulated by wheat leaves, and humic acid chelated selenium had no significant effect on wheat yield, which was also shown in the treatments with nanoselenium and sodium selenite. Excessive accumulation of selenium in wheat grains can lead to a deterioration of processing quality. Among them, the use of excessive nanoselenium at the filling stage inhibited the accumulation of wheat grain protein, whereas humic acid chelated selenium is beneficial to grain protein accumulation and has the least negative effect on the processing quality. The accumulation of excessive selenium in wheat seeds had a negative effect on seed germination and growth; specifically, the seed vigor of wheat treated with humic acid chelated selenium was higher than that of untreated wheat. CONCLUSION: Humic acid chelated selenium is particularly suitable for the whole process of Se-enriched bread wheat production. The seed vigour of wheat treated with humic acid chelated selenium, which supplied a moderate amount of selenium, was higher than that of untreated wheat. Conversely, the accumulation of excessive selenium in wheat seeds reduced germination and seedling growth. © 2023 Society of Chemical Industry.

Identification of a predictive gene signature related to pyroptosis for the prognosis of cutaneous melanoma.

Pyroptosis is a form of inflammatory programmed cell death. However, because of no specific molecular biomarker, pyroptosis has not been considered as a novel therapeutic method to treat cutaneous melanoma (CM). Here, we identified pyroptosis genes that associate with the prognosis of CM patients and constructed an effective model for the prognostic prediction of CM patients. To identify genes related to pyroptosis that are differentially expressed in CM, we obtained gene expression data of CM patients and normal skin tissues from the Cancer Genome Atlas and the Genotype-Tissue Expression databases, and used another cohort obtained from Gene Expression Omnibus database for validation. Three genes (BST2, GBP5, and AIM2) that were associated with prognosis were found and incorporated into our prognostic model. Furthermore, we divided the patients into 2 groups: a high-risk group and a low-risk group. Functional analyses indicated that our model was correlated with patient survival and cancer growth. Multivariate and univariate Cox regressions revealed that the constructed model could serve as an independent prognostic factor for CM patients. Meanwhile, compared with other clinical characteristics, our model significantly improved the diagnostic accuracy. Gene function analysis revealed that pyroptosis genes BST2, GBP5, and AIM2 were differentially expressed in CM patients and positively associated with patient prognosis. Finally, a risk score was used to generate nomograms that displayed favorable discriminatory abilities for CM. In summary, our model could significantly predict the prognosis of CM patients and be used for the development of CM therapy.

Identification of m7G-associated lncRNA prognostic signature for predicting the immune status in cutaneous melanoma.

RNA modifications, including RNA methylation, are widely existed in cutaneous melanoma (CM). Among epigenetic modifications, N7-methylguanosine (m7G) is a kind of modification at 5' cap of RNA which participate in maintaining the stability of mRNA and various cell biological processes. However, there is still no study concerning the relationship between CM and m7G methylation complexes, METTL1 and WDR4. Here, long non-coding RNA (lncRNAs) and gene expression data of CM from the Cancer Genome Atlas (TCGA) database were retrieved to identify differentially expressed m7G-related lncRNAs connected with overall survival of CM. Then, Cox regression analyses was applied to construct a lncRNA risk signature, the prognostic value of identified signature was further evaluated. As a result, 6 m7G-associated lncRNAs that were significantly related to CM prognosis were incorporated into our prognostic signature. The functional analyses indicated that the prognostic model was correlated with patient survival, cancer metastasis, and growth. Meanwhile, its diagnostic accuracy was better than conventional clinicopathological characteristics. The pathway enrichment analysis showed that the risk model was enriched in several immunity-associated pathways. Moreover, the signature model was significantly connected with the immune subtypes, infiltration of immune cells, immune microenvironment, as well as several m6A-related genes and tumor stem cells. Finally, a nomogram based on the calculated risk score was established. Overall, a risk signature based on 6 m7G-associated lncRNAs was generated which presented predictive value for the prognosis of CM patients and can be further used in the development of novel therapeutic strategies for CM.

Exosome miR-23a-3p from Osteoblast Alleviates Spinal Cord Ischemia/Reperfusion Injury by Down-Regulating KLF3-Activated CCNL2 Transcription.

BACKGROUND: Spinal cord ischemia/reperfusion injury (SCIRI) is usually caused by spinal surgery or aortic aneurysm surgery and can eventually lead to paralysis or paraplegia and neurological dysfunction. Exosomes are considered as one of the most promising therapeutic strategies for SCIRI as they can pass the blood-spinal barrier. Previous studies have proved that exosomes secreted by osteocytes have a certain slowing effect on SCIRI. AIM: We aimed to explore the effect of osteoblast secreted exosomes on SCIRI. METHODS: First, neurons and osteoblasts were co-cultured under different conditions. GEO database was utilized to detect the expression of miR-23a-3p in osteoblast exosomes. SCIRI cells were treated with exosomes, and the detection was taken to prove whether miR-23a-3p could slow the progression of SCIRI. Downstream gene and the potential regulatory mechanism were explored through database and functional experiments. RESULTS: MiR-23a-3p was highly expressed in exosomes and it slowed down the process of SCIRI. Downstream mRNA KLF3 could bind to miR-23a-3p and was highly expressed in IRI. Moreover, CCNL2 was regulated by KLF3 and was highly expressed in IRI. Rescue experiments verified that miR-23a-3p suppressed the transcription of CCNL2 by targeting KLF3. CONCLUSION: Exosome miR-23a-3p from osteoblast alleviates SCIRI by down-regulating KLF3-activated CCNL2 transcription.

Case Report: Diagnostic Value of Metagenomics Next Generation Sequencing in Intracranial Infection Caused by Mucor.

mNGS(metagenomics Next Generation Sequencing), as a novel culture-independent approach, demonstrated the capability of rapid, sensitive, and accurate pathogen identification. At present, there have been many case reports about the use of mNGS to assist in the diagnosis of bacterial, fungal, viral and parasitic infections and to guide clinicians to determine appropriate treatment. However, the clinical understanding of this technique is not comprehensive, and the experience of using it is relatively limited. We reported a 53-year-old man who was admitted to hospital with a high fever and headache. His inflammatory biomarkers were markedly elevated. Based on the clinical presentation, He was initially diagnosed as having an intracranial infection of unknown etiology and received empirical antibiotics and systemic supportive treatment. But these did not relieve his symptoms. Both the blood and CSF specimens were examined using traditional culture, serological testing, and mNGS. Traditional culture and serological testing produced negative results, while the mNGS revealed the presence of a potential pathogen, mucor, in the CSF specimen. Then targeted antifungal treatment was selected quickly and his temperature gradually returned to normal. Thus, we report the case in which mNGS was an auxiliary method to diagnose mucormycosis, and discuss this case in combination with relevant literature, in order to improve the clinical cognition of this technology.

Homologous Escherichia coli Identified in Cerebrospinal Fluid and Bloodstream.

Background: Escherichia coli is an opportunistic bacterium that causes a wide range of diseases, such as bloodstream infection and central nervous system infection. The traditional culture-based method to detect E. coli usually takes more than 2 days. The object of this study is to explore the value of metagenomic next-generation sequencing (mNGS) in identifying E. coli from human cerebrospinal fluid. In addition, we investigated the infection source of E. coli through whole genome sequencing and phylogenetic analysis. Methods: We combined a clinical example to analyze the function of mNGS in pathogen detection from cerebrospinal fluid. NextSeq 550Dx platform was applied for mNGS. Next, whole genome sequencing was performed to obtain the genomic characterization of E. coli. Furthermore, we screened 20 E. coli strains from the National Center for Biotechnology Information and conducted a phylogenetic analysis. Results: A middle-aged patient who attended our hospital was diagnosed with craniopharyngioma and received surgery. The patient had recurrent fever and persistent lethargy after surgery. Cerebrospinal fluid culture firstly failed to grow the bacteria. Next the cerebrospinal fluid sample was detected by mNGS and the sequence readings of E. coli were identified. Later, E. coli was reported via the second cerebrospinal fluid culture, certifying the result of mNGS. Moreover, we also cultured carbapenem-resistant E. coli from the patient's bloodstream. Through whole genome sequencing and phylogenetic analysis, we found that the E. coli isolated from cerebrospinal fluid and the bloodstream was 100% homologous, indicating the E. coli central nervous system infection was originated from the bloodstream. Conclusion: Metagenomic next-generation sequencing is a valuable tool to identify the pathogens from cerebrospinal fluid, and seeking the infection source is of great significance in clinical diagnosis and treatment. Furthermore, carbapenem-resistant E. coli is a serious problem as the cause of bloodstream infection and central nervous system infection, and effective and adequate measures to prevent and control the present circumstance are urgent.

Assessing and predicting soil carbon density in China using CMIP5 earth system models.

Soil carbon (SC) is a key component of the carbon cycle and plays an important role in climate change; however, quantitatively assessing SC dynamics at the regional scale remains challenging. Earth system model (ESM) that considers multiple environmental factors and spatial heterogeneity has become a powerful tool to explore carbon cycle-climate feedbacks, although the performance of the ESM is diverse and highly uncertain. Thus, identifying reliable ESMs is a prerequisite for better understanding the response of SC dynamics to human activity and climate change. The 16 ESMs that participated in the fifth phase of the Coupled Model Intercomparison Project (CMIP5) were employed to evaluate the skill performance of SC density simulation by comparison with reference data from the International Geosphere-Biosphere Programme Data and Information System (IGBP-DIS). Although ESMs generally reflect spatial patterns with lower SC in northwest China and higher SC in southeast China, 11 of 16 ESMs underestimated the SC in China, and 5 of 16 ESMs overestimated the SC density as most ESMs had large discrepancies in capturing the SC density in the northern high latitudes of China and the Qinghai-Tibet Plateau. According to a series of model performance statistics, SC simulated by Institute Pierre Simon Laplace (IPSL) Coupled Model had a close spatial pattern with IGBP-DIS and showed higher skills for SC predictions in China relative to other CMIP5 ESMs. The multimodel ensemble average obtained by IPSL family ESMs showed that SC density exhibited increasing trends under both the RCP4.5 scenario and RCP8.5 scenario. The SC density increased slowly under RCP8.5 compared with that under RCP4.5 and even displayed a decreasing trend in the late 21st century. The findings of this study can provide a reference for identifying the shortcomings of SC predictions in China and guide SC parameterization improvement in ESMs.

External electric field reduces the explosive sensitivity: a theoretical investigation into the hydrogen transference kinetics of the NH2NO2∙∙∙H2O complex.

Controlling the selectivity of detonation initiation reaction to reduce the explosive sensitivity has been a Holy Grail in the field of energetic materials. The effects of the external electric fields on the homolysis of the N-NO2 bond and initiation reaction dynamics of NH2NO2∙∙∙H2O (i.e., intermolecular and 1,3-intramolecular hydrogen transfers) were investigated at the MP2/6-311++G(2d,p) and CCSD/6-311++G(2d,p)//MP2/6-311++G(2d,p) levels. The results show that the N-NO2 bond is not the "trigger linkage." The notable transiliences of the activation energy of the intermolecular hydrogen transfer are found with the field strength of - 0.012 a.u. along the -x-direction, leading to the conversion of the main reaction between the intermolecular and 1,3-intramolecular hydrogen transference. The activation energies of two kinds of the hydrogen transferences are increased under the external electric fields along the -y-direction. In particular, due to the conversion of the main reaction, the activation energies of the overall reaction are increased significantly along the -x-direction, leading to the significant reduced explosive sensitivities. Therefore, by controlling the field strengths and orientations between the "reaction axis" and external electric field along the y- and x-directions, the selectivity of the initiation reaction could be controlled and the explosive sensitivity could be reduced. Employing AIM (atoms in molecules) and surface electrostatic potentials, the origin of the control of reaction selectivity and the reduction of sensitivity is revealed. This work is of great significance to the improvement of the technology that the external electric fields are added safely into the energetic material system to enhance the explosive performance. Graphical abstract.

Dynamic Calibration and Verification Device of Measurement System for Dynamic Characteristic Coefficients of Sliding Bearing.

The identification accuracy of dynamic characteristics coefficients is difficult to guarantee because of the errors of the measurement system itself. A novel dynamic calibration method of measurement system for dynamic characteristics coefficients is proposed in this paper to eliminate the errors of the measurement system itself. Compared with the calibration method of suspension quality, this novel calibration method is different because the verification device is a spring-mass system, which can simulate the dynamic characteristics of sliding bearing. The verification device is built, and the calibration experiment is implemented in a wide frequency range, in which the bearing stiffness is simulated by the disc springs. The experimental results show that the amplitude errors of this measurement system are small in the frequency range of 10 Hz-100 Hz, and the phase errors increase along with the increasing of frequency. It is preliminarily verified by the simulated experiment of dynamic characteristics coefficients identification in the frequency range of 10 Hz-30 Hz that the calibration data in this frequency range can support the dynamic characteristics test of sliding bearing in this frequency range well. The bearing experiments in greater frequency ranges need higher manufacturing and installation precision of calibration device. Besides, the processes of calibration experiments should be improved.

Flagellin modulates TIM4 expression in mast cells.

T-helper (Th) 2 polarization functions in a number of immune diseases, but their pathogenesis needs further investigation. Some microbial products or components are strong adjuvants in the creation of mouse models of Th2 polarization. T cell immunoglobulin mucin molecule (TIM) 4 is a facilitator in the initiation of Th2 response. This study looks at the role of one of the microbial products, flagellin (FGN), in the induction of TIM4 expression in mast cells. Bone marrow derived mast cells (BMMC) were generated. Induction of TIM4 in mast cells was assessed in both experiments in vitro and in vivo. The signal transducer and activator of transcription 6 (Stat6) phosphorylation in BMMC were assessed by Western blotting. A coculture model with FGN-primed BMMC and naïve CD4(+) T cells was employed to assess FGN in facilitating the expression of TIM4 in mast cells. After exposure to FGN, TIM4 levels were significantly increased in BMMC and mast cells of the mouse intestine, which was accompanied by increased STAT6 phosphorylation. Culture with FGN-primed BMMC, naïve CD4(+) T cells developed into Th2 cells by a TIM4-dependent manner. We conclude that FGN can induce mast cells to express TIM4, which helps initiate Th2 polarization.

CD98 positive eosinophils contribute to T helper 1 pattern inflammation.

BACKGROUND AND AIMS: The pathogenesis of inflammatory bowel disease (IBD) has not been fully understood yet. Eosinophils (Eo) are one type of the major proinflammatory cells of the chronic inflammation in the intestine. CD98 is involved in the pathogenesis of a number of inflammations. This study aims to elucidate the role of CD98(+) Eos in the initiation of intestinal inflammation. METHODS: The colon biopsies were collected from 60 patients with IBD. The expression of CD98 in the biopsies was examined by immunohistochemistry. The serum levels of the flagellin (FGN) antibody and Eo-derived mediators in the culture supernatants were assessed by enzyme-linked immunosorbent assay. The role of FGN on Eo activation was examined in a cell culture model. The role of FGN in the induction of colitis was observed in a mouse model. RESULTS: Compared to normal controls, the frequency of CD98(+) Eos was markedly increased in the IBD colon mucosa. FGN were detected in the colon biopsies and in the sera of IBD patients. Exposure to FGN induced the expression of galectin 3 (the ligand of CD98) in dendritic cells. The exposure to galectin 3 activated the CD98(+) Eos. After treatment with FGN intrarectally, mice with eosinophilia showed severe inflammation in the colon. CONCLUSIONS: The interaction of galectin 3 and CD98 can induce Eos to release chemical mediators that contributes to the initiation of the intestinal inflammation.