Identification and characterization of an α-1,3 mannosidase from Elizabethkingia meningoseptica and its potential attenuation impact on allergy associated with cross-reactive carbohydrate determinant.

Core α-1,3 mannose is structurally near the core xylose and core fucose on core pentasaccharide from plant and insect glycoproteins. Mannosidase is a useful tool for characterization the role of core α-1,3 mannose in the composition of glycan related epitope, especially for those epitopes in which core xylose and core fucose are involved. Through functional genomic analysis, we identified a glycoprotein α-1,3 mannosidase and named it MA3. We used MA3 to treat allergen horseradish peroxidase (HRP) and phospholipase A2 (PLA2) separately. The results showed that after MA3 removed α-1,3 mannose on HRP, the reactivity of HRP with anti-core xylose polyclonal antibody almost disappeared. And the reactivity of MA3-treated PLA2 with anti-core fucose polyclonal antibody decreased partially. In addition, when PLA2 was conducted enzyme digestion by MA3, the reactivity between PLA2 and allergic patients' sera diminished. These results demonstrated that α-1,3 mannose was an critical component of glycan related epitope.

A Natural Compound Containing a Disaccharide Structure of Glucose and Rhamnose Identified as Potential N-Glycanase 1 (NGLY1) Inhibitors.

N-glycanase 1 (NGLY1) is an essential enzyme involved in the deglycosylation of misfolded glycoproteins through the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway, which could hydrolyze N-glycan from N-glycoprotein or N-glycopeptide in the cytosol. Recent studies indicated that NGLY1 inhibition is a potential novel drug target for antiviral therapy. In this study, structure-based virtual analysis was applied to screen candidate NGLY1 inhibitors from 2960 natural compounds. Three natural compounds, Poliumoside, Soyasaponin Bb, and Saikosaponin B2 showed significantly inhibitory activity of NGLY1, isolated from traditional heat-clearing and detoxifying Chinese herbs. Furthermore, the core structural motif of the three NGLY1 inhibitors was a disaccharide structure with glucose and rhamnose, which might exert its action by binding to important active sites of NGLY1, such as Lys238 and Trp244. In traditional Chinese medicine, many compounds containing this disaccharide structure probably targeted NGLY1. This study unveiled the leading compound of NGLY1 inhibitors with its core structure, which could guide future drug development.

[Vitamins and Immune System Health].

Keeping the immune system healthy forms an effective way to fight infections. Past experience has shown that, in addition to effective interventions including vaccination, drug therapy, and non-pharmaceutical intervention (NPI), dietary nutrition and mental health are also key factors in maintaining immune system health and combating emerging and sudden outbreaks of infections. As the main dietary nutrients, vitamins are active regulators of the immune response and exert a critical impact on the immunity of the human body. Vitamin deficiency causes increased levels of inflammation and decreased immunity, which usually starts in the oral tissues. Appropriate vitamin supplementation can help the body optimize immune function, enhance oral immunity, and reduce the negative impact of pathogen infection on the human body, which makes it a feasible, effective, and universally applicable anti-infection solution. This review focuses on the immunomodulatory effects of vitamin A, B, C, D, and E and proposes that an omics-based new systemic approach will lead to a breakthrough of the limitations in traditional single-factor single-pathway research and provide the direction for the basic and applied research of vitamin immune regulation and anti-infection in all aspects.

Identification and characterization of a core fucosidase from the bacterium Elizabethkingia meningoseptica.

All reported α-l-fucosidases catalyze the removal of nonreducing terminal l-fucoses from oligosaccharides or their conjugates, while having no capacity to hydrolyze core fucoses in glycoproteins directly. Here, we identified an α-fucosidase from the bacterium Elizabethkingia meningoseptica with catalytic activity against core α-1,3-fucosylated substrates, and we named it core fucosidase I (cFase I). Using site-specific mutational analysis, we found that three acidic residues (Asp-242, Glu-302, and Glu-315) in the predicted active pocket are critical for cFase I activity, with Asp-242 and Glu-315 acting as a pair of classic nucleophile and acid/base residues and Glu-302 acting in an as yet undefined role. These findings suggest a catalytic mechanism for cFase I that is different from known α-fucosidase catalytic models. In summary, cFase I exhibits glycosidase activity that removes core α-1,3-fucoses from substrates, suggesting cFase I as a new tool for glycobiology, especially for studies of proteins with core fucosylation.

Identification and characterization of a novel glycoprotein core xylosidase from the bacterium Elizabethkingia meningoseptica.

Although core xylose on glycoproteins has been implicated in allergy, infection and other biological processes, research on core xylose modification is rare. The lack of a ß-d-xylosidase that can catalytically remove the core xylose directly from glycoproteins is a reason for this. Through functional genomic analysis, we identified a glycoprotein core xylosidase and named it gpcXase I. gpcXase I is located immediately downstream of glycoprotein core fucosidase cFase I in Elizabethkingia meningoseptica. These two genes form a functional operon for glycoprotein core modifications. Three acidic residues (Asp-200, Asp-304 and Glu-649) were identified as key catalytic sites for gpcXase I activity, suggesting a unique triacdic mechanize for its activity. Asp-200 was identified a novel and essential base catalysts in the catalytic process, Asp-304 and Glu-649 was function as catalytic nucleophiles and acid catalysts, respectively. In addition, IgE-specific reactions were detected in 55% of serum samples collected from 40 allergic patients, and the reactions were significantly attenuated by removal of the core xylose of the allergen by treatment with gpcXase I. gpcXase I is a novel tool for basic and clinical glycomics.

Identification and characterization of a novel prokaryotic peptide: N-glycosidase from Elizabethkingia meningoseptica.

Peptide:N-glycosidase (PNGase) F, the first PNGase identified in prokaryotic cells, catalyzes the removal of intact asparagine-linked oligosaccharide chains from glycoproteins and/or glycopeptides. Since its discovery in 1984, PNGase F has remained as the sole prokaryotic PNGase. Recently, a novel gene encoding a protein with a predicted PNGase domain was identified from a clinical isolate of Elizabethkingia meningoseptica. In this study, the candidate protein was expressed in vitro and was subjected to biochemical and structural analyses. The results revealed that it possesses PNGase activity and has substrate specificity different from that of PNGase F. The crystal structure of the protein was determined at 1.9 Å resolution. Structural comparison with PNGase F revealed a relatively larger glycan-binding groove in the catalytic domain and an additional bowl-like domain with unknown function at the N terminus of the candidate protein. These structural and functional analyses indicated that the candidate protein is a novel prokaryotic N-glycosidase. The protein has been named PNGase F-II.

Diagnosis and treatment of peritoneal dialysis associated mycotic peritonitis caused by Aspergillus fumigatus infection.

Aspergillus peritonitis is a rare but highly severe complication of peritoneal dialysis with a high mortality rate. We report a case of Aspergillus fumigatus peritonitis. Despite early removal of the catheter and oral voriconazole antifungal treatment for 3 weeks, the treatment effect was unsatisfactory, resulting in prolonged hospital stay and affecting the patient's quality of life. After switching to liposomalAmphotericin B, inflammation indicators rapidly decreased and infection was controlled. Liposomalamphotericin B provides an option for treatment of Aspergillus peritonitis.

Identification and characterization of emGalaseE, a ß-1,4 galactosidase from Elizabethkingia meningoseptica, and its application on living cell surface.

The biological function of terminal galactose on glycoprotein is an open field of research. Although progress had being made on enzymes that can remove the terminal galactose on glycoproteins, there is a lack of report on galactosidases that can work directly on living cells. In this study, a unique beta 1,4 galactosidase was isolated from Elizabethkingia meningoseptica (Em). It exhibited favorable stability at various temperatures (4-37 °C) and pH (5-8) levels and can remove ß-1, 4 linked galactoses directly from glycoproteins. Using Alanine scanning, we found that two acidic residues (Glu-468, and Glu-531) in the predicted active pocket are critical for galactosidase activity. In addition, we also demonstrated that it could cleave galactose residues present on living cell surface. As this enzyme has a potential application for living cell glycan editing, we named it emGalaseE or glycan-editing galactosidase I (csgeGalaseI). In summary, our findings lay the groundwork for further investigation by presenting a simple and effective approach for the removal of galactose moieties from cell surface.

Functional prediction of the potential NGLY1 mutations associated with rare disease CDG.

Genetic diseases are currently diagnosed by functional mutations. However, only some mutations are associated with disease. It is necessary to establish a quick prediction model for clinical screening. Pathogenic mutations in NGLY1 cause a rare autosomal recessive disease known as congenital disorder of deglycosylation (NGLY1-CDDG). Although NGLY1-CDDG can be diagnosed through gene sequencing, clinical relevance of a detected mutation in NGLY1 needs to be further confirmed. In this study, taken NGLY1-CDDG as an example, a comprehensive and practical predictive model for pathogenic mutations on NGLY1 through an NGLY1/Glycopeptide complex model was constructed, the binding sites of NGLY1 and glycopeptides were simulated, and an in vitro enzymatic assay system was established to facilitate quick clinical decisions for NGLY1-CDDG patients. The docking model covers 42 % of reported NGLY1-CDDG missense mutations (5/12). All reported mutations were subjected to in vitro enzymatic assay in which 18 mutations were dysfunctional (18/30). In addition, a full spectrum of functional R328 mutations was assayed and 11 mutations were dysfunctional (11/19). In this study, a model of NGLY1 and glycopeptides was built for potential functional mutations in NGLY1. In addition, the effect of potential regulatory compounds, including N-acetyl-l-cysteine and dithiothreitol, on NGLY1 was examined. The established in vitro assay may serve as a standard protocol to facilitate rapid diagnosis of all mutations in NGLY1-CDDG. This method could also be applied as a comprehensive and practical predictive model for the other rare genetic diseases.

Characterization and Molecular Mechanism of Aminoglycoside-6-Adenyl Transferase Associated with Aminoglycoside Resistance from Elizabethkingia meningoseptica.

Purpose: Elizabethkingia meningoseptica (EM) is a multi-drug-resistant bacterium of global concern for its role in nosocomial infection and is generally resistant to aminoglycoside antibiotics. In the whole genome of an EM strain (FMS-007), an aminoglycoside-6-adenyl transferase gene (ant(6)FMS-007) was predicted. This study aimed to characterize the biochemical function of ANT(6)FMS-007 and analyze the relationship between genotype and phenotype of ant(6) in clinical EM isolates, so as to provide evidence for clinical precision drug use. This study could establish a method for the verification of known or unknown functionally resistant genes. Methods: A total of 42 EM clinical isolates were collected from clinical departments during 2015-2023. The phenotype of aminoglycoside antibiotics was analyzed by broth microdilution (BMD) and Kirby-Bauer (K-B) methods. The whole-length ant(6) from EM clinical isolates was analyzed by polymerase chain reaction (PCR) and sequencing. The biochemical function of predictive ANT(6)FMS-007 from the FMS-007 whole genome was identified by 3D plate experiment and mass spectrometry analysis. Candidate active sites were predicted by multi-species sequence alignment and molecular docking, and other important sites were identified in the comparison of ant(6) genotypes and phenotypes of EM clinical isolates. Drug susceptibility test was used to verify the function of these sites. Results: The predictive ANT(6)FMS-007 protein could inactivate STR by modifying STR with ATP to form STR-AMP. Four active sites (Asp-38, Asp-42, Lys-95, and Lys-213) of ANT(6)FMS-007 were identified. Thirty-one EM clinical isolates (74%) carried the ant(6) gene. Eight EM clinical isolates containing the ant(6) gene had MIC values (<=32µg/mL) lower by at least 16-fold than FMS-007 (512µg/mL) for STR, and N59H and K204Q were the common mutations in the ant(6) gene. Conclusion: This assay verified the biochemical function of the predictive gene ant(6)FMS-007 and could provide an alternative method to study resistant gene function in multi-drug-resistant bacteria. The inconsistency between genotype and phenotype of resistant genes indicated that the combination of resistance gene detection and functional analysis could better provide precision medicine for clinical use.

Single Cell Raman Spectroscopy Deuterium Isotope Probing for Rapid Antimicrobial Susceptibility Test of Elizabethkingia spp.

Nosocomial infection by multi-drug resistance Elizabethkingia spp. is an emerging concern with severe clinical consequences, particularly in immunocompromised individuals and infants. Efficient control of this infection requires quick and reliable methods to determine the appropriate drugs for treatment. In this study, a total of 31 Elizabethkingia spp., including two standard strains (ATCC 13253 and FMS-007) and 29 clinical isolates obtained from hospitals in China were subjected to single cell Raman spectroscopy analysis coupled with deuterium probing (single cell Raman-DIP). The results demonstrated that single cell Raman-DIP could determine antimicrobial susceptibility of Elizabethkingia spp. in 4 h, only one third of the time required by standard broth microdilution method. The method could be integrated into current clinical protocol for sepsis and halve the report time. The study also confirmed that minocycline and levofloxacin are the first-line antimicrobials for Elizabethkingia spp. infection.

Protective Effect of Adalimumab on Diabetic Nephropathy by Regulating TNF-α Signal Pathway.

Background: To evaluate the inhibitory effect of adalimumab on diabetic nephropathy (DN) through animal models. Methods: We carried out the study in Weifang People's Hospital, Weifang 261041, China in December 2020. Streptozotocin was used to induce DN in model animal Sprague-Dawley (SD) rats. The DN animal model was given treatment with adalimumab, and the inhibitory effect of adalimumab on the development process of DN was evaluated by detecting changes in blood glucose and urinary albumin levels. Meanwhile, the content of UN, Cr and CysC of the blood in different experimental groups was tested by weighing the ratio of kidney and performing ELISA to evaluate the protective effect of adalimumab on kidney of DN animal model. In addition, the changes in the transcription and translation levels of tumor necrosis factor alpha (TNF-α) and its downstream regulatory factors MCP-1 and NF-kB in kidney of different experimental groups were detected by fluorescence quantitative PCR and Western blot tests to further reveal the molecular mechanism of adalimumab inhibiting the diabetic nephropathy. Results: adalimumab could significantly downregulate blood glucose and urinary albumin levels (P <0.05). The renal body weight ratio and the contents of UN, Cr and Cysc in blood in the adalimumab group were significantly lower than those in the placebo group (P <0.05). Meanwhile, adalimumab could significantly downregulate the expression of these molecules (P <0.05). Conclusion: adalimumab could exert its therapeutic effect on diabetic nephropathy through its specific targeting TNF-α signaling pathways.

Socioeconomic Status and Risk-Taking Behavior Among Chinese Adolescents: The Mediating Role of Psychological Capital and Self-Control.

Risk-taking behavior is particularly widespread during adolescence, and negatively impacts the healthy growth and social adaptation of adolescents. Utilizing problem-behavior theory (PBT) and the family stress model (FSM), the current study examined the relationship between socioeconomic status (SES) and adolescents' risk-taking behavior, as well as the mediating role of psychological capital and self-control. A total of 1,156 Chinese adolescent students (Mage = 15.51, 48% boys) completed a series of questionnaires anonymously. The results showed that: (1) Socioeconomic status was negatively correlated with adolescents' risk-taking behavior; (2) Both psychological capital and self-control mediated the relationship between SES and adolescents' risk-taking behavior independently; and (3) Psychological capital and self-control also mediated the relationship between SES and the risk-taking behavior of adolescents sequentially. This study reveals the internal mechanism of risk-taking behavior during adolescence and provides theoretical support and empirical evidence for preventing and reducing such behavior in this age group.

Growth inhibition by bacterial Cas2Em proteins expressed in mammalian cells.

BACKGROUND: Clustered regularly interspaced short palindromic repeats (CRISPRs) and the CRISPR-associated (Cas) proteins are bacterial adaptive immune system for survival. In our previous study, we demonstrate that polyploid giant bacterial cells (PGBC) induced by Cas2 protein is a step required by new spacer acquisition reaction catalyzed by Cas1/Cas2 complex. We also demonstrated that a carboxyl terminal domain on Cas2Em (the protein Cas2 cloned from Elizabethkingia meningoseptica) is sufficient and enough for PGBC. Thus, the potential role of Cas2Em in microbial-host interaction was explored in this study. METHODS: The impacts of Cas2Em on growth of both CHO-K1 and Hela cells were investigated. The subcellular localization and potential molecular target of Ca2Em were studied. RESULTS: The growth of mammalian cells were inhibited by Cas2Em protein via G1 arresting and apoptosis. In addition, we also demonstrated that Cas2Em was tightly associated with nuclear outer membrane and could be immunoprecipitated with 14-3-3γ through a 30 amino acid domain (homology of CLK2). CONCLUSION: Cas2Em significantly suppressed the growth of mammalian cells indicating Cas2 proteins play an important role in mammalian cells.

Filamentation initiated by Cas2 and its association with the acquisition process in cells.

Cas1-and-Cas2-mediated new spacer acquisition is an essential process for bacterial adaptive immunity. The process is critical for the ecology of the oral microflora and oral health. Although molecular mechanisms for spacer acquisition are known, it has never been established if this process is associated with the morphological changes of bacteria. In this study, we demonstrated a novel Cas2-induced filamentation phenotype in E. coli that was regulated by co-expression of the Cas1 protein. A 30 amino acid motif at the carboxyl terminus of Cas2 is necessary for this function. By imaging analysis, we provided evidence to argue that Cas-induced filamentation is a step coupled with new spacer acquisition during which filaments are characterised by polyploidy with asymmetric cell division. This work may open new opportunities to investigate the adaptive immune response and microbial balance for oral health.

Silencing of ZNF217 gene influences the biological behavior of a human ovarian cancer cell line.

Zinc-finger protein 217 (ZNF217), a candidate oncogene on 20q13.2, can lead cultured human ovarian and mammary epithelial cells to immortalization, which indicates selective expression of ZNF217 affecting 20q13 amplification during critical early stages of cancer progression. In this study, we tested the hypothesis that ZNF217 is a key factor in regulating ovarian cancer proliferation and progression. We examined the effect of the inhibition of ZNF217 expression on proliferation and invasion by establishing the ZNF217 knockdown ovarian cancer cell line using RNA interference (RNAi). Our results showed that silencing of ZNF217 resulted in the effective inhibition of ovarian cancer cell growth and invasive ability. The results suggested that ZNF217 might play a crucial role in the proliferation and invasion of ovarian cancer.

[A clinicopathologic study of dysembryoplstic neuroepithelial tumor].

UNLABELLED: OBJECTIVE To study the clinicopathologic features, radiologic findings, treatment modalities and prognosis of dysembryoplastic neuroepithelial tumor (DNT). METHODS: The clinical features, histopathologic findings, immunohistochemistry and electron microscopy of 18 cases of DNT were analyzed. Results Among the 18 cases studied, 14 were males and 4 females. The age of these patients ranged from 3 to 46 (mean age = 22. 8 years). Partial seizure was the main presenting symptom in all patients. The history of epilepsy could be as long as 17 years. On magnetic resonance imaging (MRI) study, the tumor was hypodense on T1 and hyperdense on T2. There was neither edema nor mass effect. All but 2 cases were supratentorial and intracortical in location. Ten cases were treated by complete surgical excision and the remaining 8 tumors were partially excised. In the 14 patients with follow-up data available, 13 survived for 1.4 to 11 years after the operation (with more than 10 years survival observed in 2 patients). The average survival period was 5.5 years. None of the cases showed tumor recurrence after operation. Histologically, all tumors demonstrated a multinodular architecture and were intracortical in location, sometimes with extension into the white matter. The characteristic "glioneuronal constituent" was an essential feature for making the diagnosis of DNT. The tumor was formed by an admixture of oligodendrocyte-like cells, mature neurons and astrocytes, with obvious microcystic changes. These neurons were often dispersed singly in the mucoid matrix. In most cases, the foci of cortical dysplasia were found in adjacent areas. Immunohistochemical study demonstrated positivity for synaptophysin, neurofilament and S-100 protein in the neurons and some oligodendrocyte-like cells. The staining of glial fibrillary acidic protein in the oligodendrocyte-like cells was negative. Electron microscopy showed early neuronal, astrocytic and oligodendroglial differentiation of the oligodendrocyte-like cells. CONCLUSIONS: DNT is a benign tumor (corresponding to WHO grade I) that can be cured by surgical excision, despite sometimes incomplete tumor removal. A correct diagnosis of this entity requires thorough understanding of the clinical, radiologic, histologic and immunohistochemical features.

Complete Genome Sequence of Elizabethkingia meningoseptica, Isolated from a T-Cell Non-Hodgkin's Lymphoma Patient.

An Elizabethkingia meningoseptica infection was detected at the end stage of a patient with T-cell non-Hodgkin's lymphoma. The complete genome of this isolated strain, FMS-007, was generated in one contig with a total size of 3,938,967 bp. A preliminary screening indicated that the genome contains drug resistance genes to aminoglycosides and ß-lactams. A clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated proteins (CRISPR/Cas) system with 16 direct repeats and 15 spacers was identified.

[A clinicopathological and prognostic study of 22 cases central neurocytoma].

OBJECTIVE: To investigate the clinicopathological features and prognosis of 22 cases of central neurocytoma (CNC), representing 0.48% of a series of 4 528 patients undergoing biopsy for central nervous system tumors. METHODS: The histopathological, ultrastructral, immunohistochemical and clinical features of CNC were studied by electron microscopic examination and immunohistochemical stain for Synaptophysin (Syn), neuron special enolase (NSE), Leu-7, glial fibrillary acid protein (GFAP), MBP and proliferating cell nuclear antigen (PCNA). RESULTS: The age of the cases ranged from 4 to 44 (average 27.9 years) with all tumors localized in the ventricles. In the 18 patients followed up, 14 were alive for 8 months to 14 years and 11 months after the operation, and 4 died. The average survival period was 70.7 months. Histologically, the tumor in all 22 cases had the oligodendroglioma-like pattern with honeycomb appearance and cell-free islands of eosinophilic matrix. Cellular anaplasia, mitosis and necrotic areas were rarely seen in the tumors. Immunohistochemical study demonstrated strong positivity for Syn, NSE and Leu-7, and negative for GFAP and MBP. Ultrastructural features showed presence of round tumor cells with abundant cell processes containing microtubules, neurosecretory granules, clear vesicles and lysosome-like structures. CONCLUSIONS: The differential diagnosis between CNC and oligodendroglioma could not be established by routine light microscopy. The importance of immunohistochemical and electron microscopic studies for making a correct diagnosis is emphasized. The prognosis of patients is usually favorable, even if the tumor was resected subtotally. The relationship between the presence of anaplastic histological features in CNC and patient outcome remains unclear.