Specificity Enhancement of Glutenase Bga1903 toward Celiac Disease-Eliciting Pro-Immunogenic Peptides via Active-Site Modification

Celiac disease is an autoimmune disease triggered by oral ingestion of gluten, with certain gluten residues resistant to digestive tract enzymes. Within the duodenum, the remaining peptides incite immunogenic responses, including the generation of autoantibodies and inflammation, leading to irreversible damage. Our previous exploration unveiled a glutenase called Bga1903 derived from the Gram-negative bacterium Burkholderia gladioli. The cleavage pattern of Bga1903 indicates its moderate ability to mitigate the toxicity of pro-immunogenic peptides. The crystal structure of Bga1903, along with the identification of subsites within its active site, was determined. To improve its substrate specificity toward prevalent motifs like QPQ within gluten peptides, the active site of Bga1903 underwent site-directed mutagenesis according to structural insights and enzymatic kinetics. Among the double-site mutants, E380Q/S387L exhibits an approximately 34-fold increase in its specificity constant toward the QPQ sequence, favoring glutamines at the P1 and P3 positions compared to the wild type. The increased specificity of E380Q/S387L not only enhances its ability to break down pro-immunogenic peptides but also positions this enzyme variant as a promising candidate for oral therapy for celiac disease.

Hydrolysis of Gluten-Derived Celiac Disease-Triggering Peptides across a Broad pH Range by RmuAP1: A Novel Aspartic Peptidase Isolated from Rhodotorula mucilaginosa

An aspartate peptidase with proteolytic activity toward gluten was identified from an isolated red yeast Rhodotorula mucilaginosa strain. This peptidase consists of 425 amino acids, comprising an N-terminal signal peptide, a propeptide, and a C-terminal catalytic domain. The catalytic domain, termed RmuAP1CD, could be secreted by the recombinant oleaginous yeast Yarrowia lipolytica, whose genome contains the expression cassette for RmuAP1CD. RmuAP1CD exhibited optimum activity at pH 2.5 when acting on bovine serum albumin. Moreover, it facilitated the hydrolysis of gluten-derived immunogenic peptides (GIPs), which are responsible for triggering celiac disease symptoms, across a pH range of 3.0-6.0. The preferred cleavage sites are P-Q-Q-↓-P-Q in the 26-mer and P-Q-L-↓-P-Y in the 33-mer GIPs. Conversely, porcine pepsin cannot hydrolyze these two GIPs. The ability of RmuAP1CD to degrade GIPs under acidic conditions of the stomach indicates its potential as a viable oral enzyme therapy for celiac disease.

Harnessing microbial phylum-specific molecular markers for assessment of environmental estrogen degradation

Steroidal estrogens are ubiquitous contaminants that have garnered attention worldwide due to their endocrine-disrupting and carcinogenic activities at sub-nanomolar concentrations. Microbial degradation is one of the main mechanisms through which estrogens can be removed from the environment. Numerous bacteria have been isolated and identified as estrogen degraders; however, little is known about their contribution to environmental estrogen removal. Here, our global metagenomic analysis indicated that estrogen degradation genes are widely distributed among bacteria, especially among aquatic actinobacterial and proteobacterial species. Thus, by using the Rhodococcus sp. strain B50 as the model organism, we identified three actinobacteria-specific estrogen degradation genes, namely aedGHJ, by performing gene disruption experiments and metabolite profile analysis. Among these genes, the product of aedJ was discovered to mediate the conjugation of coenzyme A with a unique actinobacterial C17 estrogenic metabolite, 5-oxo-4-norestrogenic acid. However, proteobacteria were found to exclusively adopt an α-oxoacid ferredoxin oxidoreductase (i.e., the product of edcC) to degrade a proteobacterial C18 estrogenic metabolite, namely 3-oxo-4,5-seco-estrogenic acid. We employed actinobacterial aedJ and proteobacterial edcC as specific biomarkers for quantitative polymerase chain reaction (qPCR) to elucidate the potential of microbes for estrogen biodegradation in contaminated ecosystems. The results indicated that aedJ was more abundant than edcC in most environmental samples. Our results greatly expand the understanding of environmental estrogen degradation. Moreover, our study suggests that qPCR-based functional assays are a simple, cost-effective, and rapid approach for holistically evaluating estrogen biodegradation in the environment.

Targeting histone deacetylase-3 blocked epithelial-mesenchymal plasticity and metastatic dissemination in gastric cancer

BACKGROUND AND PURPOSE

Histone deacetylase (HDAC) inhibitors (HDIs) can modulate the epithelial-mesenchymal transition (EMT) progression and inhibit the migration and invasion of cancer cells. Emerging as a novel class of anti-cancer drugs, HDIs are attracted much attention in the field of drug discovery. This study aimed to discern the underlying mechanisms of Honokiol in preventing the metastatic dissemination of gastric cancer cells by inhibiting HDAC3 activity/expression.

EXPERIMENTAL APPROACH

Clinical pathological analysis was performed to determine the relationship between HDAC3 and tumor progression. The effects of Honokiol on pharmacological characterization, functional, transcriptional activities, organelle structure changes, and molecular signaling were analyzed using binding assays, differential scanning calorimetry, luciferase reporter assay, HDAC3 activity, ER stress response element activity, transmission electron microscopy, immune-blotting, and Wnt/β-catenin activity assays. The in vivo effects of Honokiol on peritoneal dissemination were determined by a mouse model and detected by PET/CT tomography.

KEY RESULTS

HDAC3 over-expression was correlated with poor prognosis. Honokiol significantly abolished HDAC3 activity (Y298) via inhibition of NFκBp65/CEBPβ signaling, which could be reversed by the over-expression of plasmids of NFκBp65/CEBPβ. Treatments with 4-phenylbutyric acid (a chemical chaperone) and calpain-2 gene silencing inhibited Honokiol-inhibited NFκBp65/CEBPβ activation. Honokiol increased ER stress markers and inhibited EMT-associated epithelial markers, but decreased Wnt/β-catenin activity. Suppression of HDAC3 by both Honokiol and HDAC3 gene silencing decreased cell migration and invasion in vitro and metastasis in vivo.

CONCLUSIONS AND IMPLICATIONS

Honokiol acts by suppressing HDAC3-mediated EMT and metastatic signaling. By prohibiting HDAC3, metastatic dissemination of gastric cancer may be blocked. Conceptual model showing the working hypothesis on the interaction among Honokiol, HDAC3, and ER stress in the peritoneal dissemination of gastric cancer. Honokiol targeting HDAC3 by ER stress cascade and mitigating the peritoneal spread of gastric cancer. Honokiol-induced ER stress-activated calpain activity targeted HDAC3 and blocked Tyr298 phosphorylation, subsequently blocked cooperating with EMT transcription factors and cancer progression. The present study provides evidence to demonstrate that HDAC3 is a positive regulator of EMT and metastatic growth of gastric cancer cells. The findings here imply that overexpressed HDAC3 is a potential therapeutic target for honokiol to reverse EMT and prevent gastric cancer migration, invasion, and metastatic dissemination. • Honokiol significantly abolished HDAC3 activity on catalytic tyrosine 298 residue site. In addition, Honokiol-induced ER stress markedly inhibited HDAC3 expression via inhibition of NFκBp65/CEBPβ signaling. • HDAC3, which is a positive regulator of metastatic gastric cancer cell growth, can be significantly inhibited by Honokiol. • Opportunities for HDAC3 inhibition may be a potential therapeutic target for preventing gastric cancer metastatic dissemination.

[Progress on health-related quality of life and its influencing factors in patients with tuberculosis sequelae]

With the emergence of new tuberculosis patients, the number of patients with tuberculosis sequelae is increasing, which not only increases the medical burden of tuberculosis sequelae year by year, but also affects the health-related quality of life (HRQOL) of patients. The HRQOL of patients with tuberculosis sequelae has gradually received attention, but there are few relevant studies. Studies have shown that HRQOL is related to various factors such as post-tuberculosis lung disease, adverse reaction to anti-tuberculosis drugs, decreased physical activity, psychological barriers, low economic status and marital status. This article reviewed the current situation of HRQOL in patients with sequelae of tuberculosis and its influencing factors, in order to provide a reference for improving the quality of life of patients with sequelae of tuberculosis.

An interactive feedback system for increasing hand antisepsis adherence in stationary intensive care

BACKGROUND

Pathogens causing infections are in many cases transmitted via the hands of personnel. Thus, hand antisepsis has strong epidemiological evidence of infection prevention. Depending on various factors, hand antisepsis adherence ranges between 9.1% and 85.2%.

AIM

To evaluate a new transponder system that reminded medical staff to use an alcohol-based hand rub based on indication by giving real-time feedback, to detect hand antisepsis adherence.

METHODS

The monitoring system consisted of three components: a portable transponder detecting alcohol-based hand rub and able to give feedback; a beacon recognizing entries to and exits from the patient's surroundings; and a sensor placed at the hand-rub dispensers to count the number of hand rubs. With these components, the system provided feedback when hand antisepsis was not conducted although it was necessary according to moments 1, 4, and 5 of hand antisepsis. Adherence was measured in two use-cases with five phases, starting with the baseline measurement followed by intervention periods and phases without intervention to test the sustainability of the feedback.

FINDINGS

Using the monitoring system, hand antisepsis adherence was increased by up to 104.5% in comparison to the baseline measurement. When the intervention ceased, however, hand antisepsis adherence decreased to less than or equal to the baseline measurement.

CONCLUSION

A short-term intervention alone is not sufficient to lead to a long-term change in hand antisepsis adherence. Rather, permanent feedback and/or the integration in a multi-modal intervention strategy are necessary.

A viral movement protein co-opts endoplasmic reticulum luminal-binding protein and calreticulin to promote intracellular movement

Intracellular movement is an important step for the initial spread of virus in plants during infection. This process requires virus-encoded movement proteins (MPs) and their interaction with host factors. Despite the large number of known host factors involved in the movement of different viruses, little is known about host proteins that interact with one of the MPs encoded by potexviruses, the triple-gene-block protein 3 (TGBp3). The main obstacle lies in the relatively low expression level of potexviral TGBp3 in hosts and the weak or transient nature of interactions. Here, we used TurboID-based proximity labeling to identify the network of proteins directly or indirectly interacting with the TGBp3 of a potexvirus, Bamboo mosaic virus (BaMV). Endoplasmic reticulum (ER) luminal-binding protein 4 and calreticulin 3 of Nicotiana benthamiana (NbBiP4 and NbCRT3, respectively) associated with the functional TGBp3-containing BaMV movement complexes, but not the movement-defective mutant, TGBp3M. Fluorescent microscopy revealed that TGBp3 colocalizes with NbBiP4 or NbCRT3 and the complexes move together along ER networks to cell periphery in N. benthamiana. Loss- and gain-of-function experiments revealed that NbBiP4 or NbCRT3 is required for the efficient spread and accumulation of BaMV in infected leaves. In addition, overexpression of NbBiP4 or NbCRT3 enhanced the targeting of BaMV TGBp1 to plasmodesmata (PD), indicating that NbBiP4 and NbCRT3 interact with TGBp3 to promote the intracellular transport of virion cargo to PD that facilitates virus cell-to-cell movement. Our findings revealed additional roles for NbBiP4 and NbCRT3 in BaMV intracellular movement through ER networks or ER-derived vesicles to PD, which enhances the spread of BaMV in N. benthamiana.

The Bph45 Gene Confers Resistance against Brown Planthopper in Rice by Reducing the Production of Limonene

Brown planthopper (BPH), a monophagous phloem feeder, consumes a large amount of photoassimilates in rice and causes wilting. A near-isogenic line ‘TNG71-Bph45’ was developed from the Oryza sativa japonica variety ‘Tainung 71 (TNG71) carrying a dominant BPH-resistance locus derived from Oryza nivara (IRGC 102165) near the centromere of chromosome 4. We compared the NIL (TNG71-Bph45) and the recurrent parent to explore how the Bph45 gene confers BPH resistance. We found that TNG71-Bph45 is less attractive to BPH at least partially because it produces less limonene. Chiral analysis revealed that the major form of limonene in both rice lines was the L-form. However, both L- and D-limonene attracted BPH when applied exogenously to TNG71-Bph45 rice. The transcript amounts of limonene synthase were significantly higher in TNG71 than in TNG71-Bph45 and were induced by BPH infestation only in the former. Introgression of the Bph45 gene into another japonica variety, Tainan 11, also resulted in a low limonene content. Moreover, several dominantly acting BPH resistance genes introduced into the BPH-sensitive IR24 line compromised its limonene-producing ability and concurrently decreased its attractiveness to BPH. These observations suggest that reducing limonene production may be a common resistance strategy against BPH in rice.

Chemical and mechanical stability of an ion-exchanged lithium disilicate glass in artificial saliva

Multi-component lithium disilicate (LD) glasses were ion-exchanged in a pure or mixed nitrate salt bath. The surface morphologies, mechanical properties, chemical stability and ion leaching of ion-exchanged LD glasses before and after storage in artificial saliva for 21 days were investigated. It can be found that chemical stability of ion-exchanged LD glass was temperature-dependent. The residual compressive stress induced by ion-exchange increased the chemical potential of alkali ions in glass, and the ion-exchanged LD glass, especially 235 °C/64 h group, chemical stability in artificial saliva for 21 days were deteriorated. Back-exchange treatment could relax the stress on the outermost layer of the ion-exchanged LD glass without deteriorating its strengthening effect, and back-exchanged LD glass presented good chemical and mechanical stability in artificial saliva. The results might help to enhance the service stability of ion-exchanged LD glass-ceramics in the oral condition.

Application Potential of Bacterial Volatile Organic Compounds in the Control of Root-Knot Nematodes

Plant-parasitic nematodes (PPNs) constitute the most damaging group of plant pathogens. Plant infections by root-knot nematodes (RKNs) alone could cause approximately 5% of global crop loss. Conventionally, chemical-based methods are used to control PPNs at the expense of the environment and human health. Accordingly, the development of eco-friendly and safer methods has been urged to supplement or replace chemical-based methods for the control of RKNs. Using microorganisms or their metabolites as biological control agents (BCAs) is a promising approach to controlling RKNs. Among the metabolites, volatile organic compounds (VOCs) have gained increasing attention because of their potential in the control of not only RKNs but also other plant pathogens, such as insects, fungi, and bacteria. This review discusses the biology of RKNs as well as the status of various control strategies. The discovery of VOCs emitted by bacteria from various environmental sources and their application potential as BCAs in controlling RKNs are specifically addressed.

Improving early running-in wear characteristics for dental lithium disilicate glass-ceramics by ion-exchange

OBJECTIVES

This study examined the effects of Li⁺→Na⁺ ion-exchange on the early wear performance of dental lithium disilicate (LD) glass-ceramics.

METHODS

Specimens with different shapes were prepared using IPS e.max Press as the LD glass-ceramics. Ion-exchange was conducted by placing polished specimens in molten salt containing 25% NaNO₃ and 75% KNO₃ at 385 °C for 16 or 64 h. The ion-exchanged specimens were analyzed using X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) to investigate the structure and the elemental distribution. Thereafter, the specimens were tested for flexural strength, Vickers hardness, and fracture resistance. A portion of the specimens were tested with a pin-on-disk tribometer with 10 N for 40 × 10⁴ wear cycles in artificial saliva. Wear analysis of the specimens was performed using a 3D profilometer and analyzed with one-way analyses of variance and Tukey's post hoc pairwise comparisons. Worn surfaces were examined with scanning electron microscopy.

RESULTS

The LD glass-ceramics exhibited strong time-dependent wear behavior, with typical running-in and steady wear stages. Ion-exchange treatments at 385 °C for 16 h and 64 h both enhanced the mechanical properties and decreased the wear rates of early running-in wear stage. The early wear performance of specimens treated with ion-exchange for long time (64 h) was improved significantly.

CONCLUSION

A thicker ion-exchange layer may be obtained by processing ion-exchange for a long time. This protocol improves the early wear performance of the glass-ceramics effectively.

CLINICAL SIGNIFICANCE

Dental restorations may fail prematurely due to excessive wear. It is important to improve the early wear performance of the glass-ceramics. Ion-exchange has the potential to strengthen dental LD glass-ceramics. Understanding the effect of ion-exchange on the early wear performance of glass-ceramics provides insight improving the early wear performance of these restorations.

Effect of Li+/Na+ exchange on mechanical behavior and biological activity of lithium disilicate glass-ceramic

Lithium disilicate (LD) glass-ceramics with a stoichiometric composition were ion-exchanged in pure NaNO₃ or mixed NaNO₃ + KNO₃ molten salt baths below the glass transition temperature (T_g). The microstructures, surface morphologies, mechanical properties and bioactivities of the ion-exchanged glass-ceramics were studied in detail. It was found that the strength and toughness of LD glass-ceramic could be enhanced from 175 MPa to 0.96 MPa m^1/2 before ion-exchange to 546 MPa and 4.31 MPa m^1/2 respectively under a lowered ion-exchange temperature because the less stress relaxation. In addition, a gradient of Na⁺ rich layer in the surface of glass-ceramic was induced by Li⁺/Na⁺ exchange, which could be beneficial to the formation of HA (Hydroxyapatite) with nano-size porous after soaking in SBF (Simulated Body Fluid) solution and exhibited better bioactivity compared with the original LD glass-ceramic. The results might provide a reference for the strengthening and biological activation of LD glass-ceramics in bone restoration applications.

The differential presence of human polyomaviruses, JCPyV and BKPyV, in prostate cancer and benign prostate hypertrophy tissues

Background

Studies have shown that human polyomavirus infection may be associated with various human cancers. We investigated the potential relationship between the prevalence of JCPyVor BKPyV and prostate cancer (PC) in patients from Taiwan.

Methods

Patients with PC and benign prostate hypertrophy (BPH; 76 and 30 patients, respectively) were recruited for this study. Paraffin-embedded tissues and clinical information of the patients were obtained. The tissue sections were used for viral DNA detection and immunohistochemistry analysis was performed for examining viral large T (LT) and VP1 proteins. Regression analysis was used to evaluate the relationship between the clinical characteristics of the patients and the risk of JCPyV/BKPyV infection.

Results

The prevalence of JCPyV/BKPyV DNA was different in PC and BPH tissues (27/76 [35.52%] and 2/30 [6.7%], respectively, p = 0.003)]. The LT and VP1 proteins were detected in 27 (35.52%) and 29 PC (38.2%) specimens, respectively, but neither protein was detected in BPH samples (p < 0.001). PC cells were more susceptible to JCPyV infection than BPH tissues [odds ratio (OR) 7.71, 95% CI: 1.71–34.09, p = 0.003). Patients with PC showing high levels of prostate-specific antigen and high Gleason scores were associated with a high risk of viral infection (ORs 1.1, 95% CI 1.000–1.003; p = 0.045 and ORs 6.18, 95% CI 1.26–30.33, p = 0.025, respectively). The expression of LT protein associated with the risk of PC increased 2923.39-fold (95% CI 51.19–166,963.62, p < 0.001).

Conclusions

The findings indicate that JCPyV infection in PC cells may be associated with prostate cancer progression and prognosis.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08862-w.

[Advances in indocyanine green fluorescence imaging during hepatectomy]

While surgical operation is the preferred treatment for liver malignancies,the postoperative recurrence rate remains high. In the early 21^st century,Japanese scientists first reported the use of indocyanine green(ICG) in liver resection. Follow-up studies also found its potential applications such as identifying tumors,determining surgical margins,delineating segmental boundaries,and preventing bile leakage. At present,ICG fluorescence imaging is applied to some types of hepatectomy with excellent effect and is expected to assist in generating surgical strategies for liver malignancies. However,its safety and efficacy still need further studies to evaluate.

NbPsbO1 Interacts Specifically with the Bamboo Mosaic Virus (BaMV) Subgenomic RNA (sgRNA) Promoter and Is Required for Efficient BaMV sgRNA Transcription

Many positive-strand (+) RNA viruses produce subgenomic RNAs (sgRNAs) in the infection cycle through the combined activities of viral replicase and host proteins. However, knowledge about host proteins involved in direct sgRNA promoter recognition is limited. Here, in the partially purified replicase complexes from Bamboo mosaic virus (BaMV)-infected tissue, we have identified the Nicotiana benthamiana photosystem II oxygen-evolving complex protein, NbPsbO1, which specifically interacted with the promoter of sgRNA but not that of genomic RNA (gRNA). Silencing of NbPsbO1 expression suppressed BaMV accumulation in N. benthamiana protoplasts without affecting viral gRNA replication. Overexpression of wild-type NbPsbO1 stimulated BaMV sgRNA accumulation. Fluorescent microscopy examination revealed that the fluorescence associated with NbPsbO1 was redistributed from chloroplast granal thylakoids to stroma in BaMV-infected cells. Overexpression of a mislocalized mutant of NbPsbO1, dTPPsbO1-T7, inhibited BaMV RNA accumulation in N. benthamiana, whereas overexpression of an NbPsbO1 derivative, sPsbO1-T7, designed to be targeted to chloroplast stroma, upregulated the sgRNA level. Furthermore, depletion of NbPsbO1 in BaMV RdRp preparation significantly inhibited sgRNA synthesis in vitro but exerted no effect on (+) or (-) gRNA synthesis, which indicates that NbPsbO1 is required for efficient sgRNA synthesis. These results reveal a novel role for NbPsbO1 in the selective enhancement of BaMV sgRNA transcription, most likely via direct interaction with the sgRNA promoter. IMPORTANCE Production of subgenomic RNAs (sgRNAs) for efficient translation of downstream viral proteins is one of the major strategies adapted for viruses that contain a multicistronic RNA genome. Both viral genomic RNA (gRNA) replication and sgRNA transcription rely on the combined activities of viral replicase and host proteins, which recognize promoter regions for the initiation of RNA synthesis. However, compared to the cis-acting elements involved in the regulation of sgRNA synthesis, the host factors involved in sgRNA promoter recognition mostly remain to be elucidated. Here, we found a chloroplast protein, NbPsbO1, which specifically interacts with Bamboo mosaic virus (BaMV) sgRNA promoter. We showed that NbPsbO1 is relocated to the BaMV replication site in BaMV-infected cells and demonstrated that NbPsbO1 is required for efficient BaMV sgRNA transcription but exerts no effect on gRNA replication. This study provides a new insight into the regulating mechanism of viral gRNA and sgRNA synthesis.

Identification of essential β-oxidation genes and corresponding metabolites for oestrogen degradation by actinobacteria

Steroidal oestrogens (C₁₈) are contaminants receiving increasing attention due to their endocrine‐disrupting activities at sub‐nanomolar concentrations. Although oestrogens can be eliminated through photodegradation, microbial function is critical for removing oestrogens from ecosystems devoid of sunlight exposure including activated sludge, soils and aquatic sediments. Actinobacteria were found to be key oestrogen degraders in manure‐contaminated soils and estuarine sediments. Previously, we used the actinobacterium Rhodococcus sp. strain B50 as a model microorganism to identify two oxygenase genes, aedA and aedB, involved in the activation and subsequent cleavage of the estrogenic A‐ring respectively. However, genes responsible for the downstream degradation of oestrogen A/B‐rings remained completely unknown. In this study, we employed tiered comparative transcriptomics, gene disruption experiments and mass spectrometry‐based metabolite profile analysis to identify oestrogen catabolic genes. We observed the up‐regulation of thiolase‐encoding aedF and aedK in the transcriptome of strain B50 grown with oestrone. Consistently, two downstream oestrogenic metabolites, 5‐oxo‐4‐norestrogenic acid (C₁₇) and 2,3,4‐trinorestrogenic acid (C₁₅), were accumulated in aedF‐ and aedK‐disrupted strain B50 cultures. Disruption of fadD3 [3aα‐H‐4α(3'‐propanoate)‐7aβ‐methylhexahydro‐1,5‐indanedione (HIP)‐coenzyme A‐ligase gene] in strain B50 resulted in apparent HIP accumulation in oestrone‐fed cultures, indicating the essential role of fadD3 in actinobacterial oestrogen degradation. In addition, we detected a unique meta‐cleavage product, 4,5‐seco‐estrogenic acid (C₁₈), during actinobacterial oestrogen degradation. Differentiating the oestrogenic metabolite profile and degradation genes of actinobacteria and proteobacteria enables the cost‐effective and time‐saving identification of potential oestrogen degraders in various ecosystems through liquid chromatography–mass spectrometry analysis and polymerase chain reaction‐based functional assays.

Mechanistic and phylogenetic insights into actinobacteria-mediated oestrogen biodegradation in urban estuarine sediments

Steroidal oestrogens are often accumulated in urban estuarine sediments worldwide at microgram per gram levels. These aromatic steroids have been classified as endocrine disruptors and group 1 carcinogens. Microbial degradation is a naturally occurring mechanism that mineralizes oestrogens in the biosphere; however, the corresponding genes in oestrogen-degrading actinobacteria remain unidentified. In this study, we identified a gene cluster encoding several putative oestrogen-degrading genes (aed; actinobacterial oestrogen degradation) in actinobacterium Rhodococcus sp. strain B50. Among them, the aedA and aedB genes involved in oestrogenic A-ring cleavage were identified through gene-disruption experiments. We demonstrated that actinobacterial oestrone 4-hydroxylase (AedA) is a cytochrome P450-type monooxygenase. We also detected the accumulation of two extracellular oestrogenic metabolites, including pyridinestrone acid (PEA) and 3aα-H-4α(3'-propanoate)-7aβ-methylhexahydro-1,5-indanedione (HIP), in the oestrone-fed strain B50 cultures. Since actinobacterial aedB and proteobacterial edcB shared < 40% sequence identity, 4-hydroxyestrone 4,5-dioxygenase genes (namely aedB and edcB) could serve as a specific biomarker to differentiate the contribution of actinobacteria and proteobacteria in environmental oestrogen degradation. Therefore, 4-hydroxyestrone 4,5-dioxygenase genes and the extracellular metabolites PEA and HIP were used as biomarkers to investigate oestrogen biodegradation in an urban estuarine sediment. Interestingly, our data suggested that actinobacteria are active oestrogen degraders in the urban estuarine sediment.

A novel dentin bonding scheme based on extrafibrillar demineralization combined with covalent adhesion using a dry-bonding technique

Dentin bonding is a dynamic process that involves the penetration of adhesive resin monomers into the extrafibrillar and intrafibrillar demineralized collagen matrix using a wet-bonding technique. However, adhesive resin monomers lack the capacity to infiltrate the intrafibrillar space, and the excess water that is introduced by the wet-bonding technique remains at the bonding interface. This imperfectly bonded interface is inclined to hydrolytic degradation, severely jeopardizing the longevity of bonded clinical restorations. The present study introduces a dentin bonding scheme based on a dry-bonding technique, combined with the use of extrafibrillar demineralization and a collagen-reactive monomer (CRM)-based adhesive (CBA). Selective extrafibrillar demineralization was achieved using 1-wt% high-molecular weight (MW) carboxymethyl chitosan (CMCS) within a clinically acceptable timeframe to create a less aggressive bonding substance for dentin bonding due to its selectively extrafibrillar demineralization capacity. CMCS demineralization decreased the activation of in situ collagenase, improved the shrinking resistance of demineralized collagen, and thus provided stronger and more durable bonding than traditional phosphoric acid etching. The new dentin bonding scheme that contained CMCS and CBA and used a dry-bonding technique achieved an encouraging dentin bonding strength and durability with low technical sensitivity. This bonding scheme can be used to improve the stability of the resin-dentin interface and foster the longevity of bonded clinical restorations.

Efficient Hydrolysis of Gluten-Derived Celiac Disease-Triggering Immunogenic Peptides by a Bacterial Serine Protease from Burkholderia gladioli

Celiac disease is an autoimmune disorder triggered by toxic peptides derived from incompletely digested glutens in the stomach. Peptidases that can digest the toxic peptides may formulate an oral enzyme therapy to improve the patients’ health condition. Bga1903 is a serine endopeptidase secreted by Burkholderia gladioli. The preproprotein of Bga1903 consists of an N-terminal signal peptide, a propeptide region, and an enzymatic domain that belongs to the S8 subfamily. Bga1903 could be secreted into the culture medium when it was expressed in E. coli. The purified Bga1903 is capable of hydrolyzing the gluten-derived toxic peptides, such as the 33- and 26-mer peptides, with the preference for the peptide bonds at the carbonyl site of glutamine (P1 position). The kinetic assay of Bga1903 toward the chromogenic substrate Z-HPQ-pNA at 37 °C, pH 7.0, suggests that the values of Km and k_cat are 0.44 ± 0.1 mM and 17.8 ± 0.4 s⁻¹, respectively. The addition of Bga1903 in the wort during the fermentation step of beer could help in making gluten-free beer. In summary, Bga1903 is usable to reduce the gluten content in processed foods and represents a good candidate for protein engineering/modification aimed to efficiently digest the gluten at the gastric condition.

Improved reliability of mechanical behavior for a thermal tempered lithium disilicate glass-ceramic by regulating the cooling rate

Traditional thermal tempering was applied to lithium disilicate (LD) glass-ceramic specimens with bar-like and disc-like shapes. The tempering process was conducted by heating the specimens to a temperature below the dynamic softening point, and then rapid cooling in silicone oil with different temperatures ranging from room-temperature to 300 °C to regulate the cooling rate. Effect of the oil-temperature on mechanical behavior of the tempered glass-ceramic was investigated. For the tempering at the lower oil-temperature (e.g., at room-temperature), it was found that the LD glass-ceramic specimens with both the bar-like and disc-like shapes could be remarkably strengthen and toughen, however, obvious anisotropy in fracture toughness was displayed by the specimens with the bar-like shape. With increasing the oil-temperature up to 250 °C, the mechanical anisotropy of the bar-like specimens could be significantly alleviated without much loss of the strengthening effect. The results can provide references for improving reliability of mechanical behavior for the tempered LD glass-ceramic by regulating the cooling condition according to specimen geometry.

Proliferating Cell Nuclear Antigen Suppresses RNA Replication of Bamboo Mosaic Virus through an Interaction with the Viral Genome

Bamboo mosaic virus (BaMV), a member of the Potexvirus genus, has a monopartite positive-strand RNA genome on which five open reading frames (ORFs) are organized. ORF1 encodes a 155-kDa nonstructural protein (REPBaMV) that plays a core function in replication/transcription of the viral genome. To find out cellular factors modulating the replication efficiency of BaMV, a putative REPBaMV-associated protein complex from Nicotiana benthamiana leaf was isolated on an SDS-PAGE gel, and a few proteins preferentially associated with REPBaMV were identified by tandem mass spectrometry. Among them, proliferating cell nuclear antigen (PCNA) was particularly noted. Overexpression of PCNA strongly suppressed the accumulation of BaMV coat protein and RNAs in leaf protoplasts. In addition, PCNA exhibited an inhibitory effect on BaMV polymerase activity. A pulldown assay confirmed a binding capability of PCNA toward BaMV genomic RNA. Mutations at D41 or F114 residues, which are critical for PCNA to function in nuclear DNA replication and repair, disabled PCNA from binding BaMV genomic RNA as well as suppressing BaMV replication. This suggests that PCNA bound to the viral RNA may interfere with the formation of a potent replication complex or block the replication process. Interestingly, BaMV is almost invisible in the newly emerging leaves where PCNA is actively expressed. Accordingly, PCNA is probably one of the factors restricting the proliferation of BaMV in young leaves. Foxtail mosaic virus and Potato virus X were also suppressed by PCNA in the protoplast experiment, suggesting a general inhibitory effect of PCNA on the replication of potexviruses.IMPORTANCE Knowing the dynamic interplay between plant RNA viruses and their host is a basic step toward first understanding how the viruses survive the plant defense mechanisms and second gaining knowledge of pathogenic control in the field. This study found that plant proliferating cell nuclear antigen (PCNA) imposes a strong inhibition on the replication of several potexviruses, including Bamboo mosaic virus, Foxtail mosaic virus, and Potato virus X Based on the tests on Bamboo mosaic virus, PCNA is able to bind the viral genomic RNA, and this binding is a prerequisite for the protein to suppress the virus replication. This study also suggests that PCNA plays an important role in restricting the proliferation of potexviruses in the rapidly dividing tissues of plants.

Improving the wear performance of feldspathic veneering porcelain by ion-exchange strengthening

OBJECTIVES

The present study examined the effects of Na⁺→K⁺ ion-exchange on the wear performance of feldspathic veneering porcelain.

METHODS

Bar and disk specimens were prepared using IPS classic as the feldspathic veneering porcelain. After ion-exchange by immersion of the specimens in melted KNO₃ at two temperatures for different time-periods, the bars were tested for flexural strength and Vickers surface hardness. The disks were paired with zirconia antagonists and tested with a pin-on-disk tribometer with 10 N for 70☓10⁴ wear cycles in artificial saliva. Wear analysis of the porcelain and zirconia was performed using 3D profilometer and analysed with one-way analysis of variance and Tukey's post-hoc pairwise comparison procedures. Worn surfaces were examined with scanning electron microscopy.

RESULTS

The feldspathic veneering porcelain exhibited strong time-dependent wear behaviour, with typical running-in and steady wear stages. Ion-exchange treatments at 380 °C and 440 °C both enhanced the mechanical properties, decreased the wear rates of running-in wear and steady wear. The wear performance of porcelain treated by ion-exchange at lower temperature (380 °C) was improved significantly, especially reducing the wear rate of the running-in stage.

CONCLUSION

A thicker ion-exchange layer with less stress relaxation may be obtained by ion-exchange at lower exchange temperature for a long processing time. Such a protocol improves the wear performance of the porcelain effectively.

CLINICAL SIGNIFICANCE

Restorations with veneering porcelain may fail prematurely due to excessive wear. It important to improve the wear performance of the porcelain. Ion-exchange has the potential to strengthen dental veneering porcelain. Understanding the effect of ion-exchange on the wear performance of porcelain provides insight improving the wear performance of these restorations.

A novel polysaccharide obtained from Craterellus cornucopioides enhances immunomodulatory activity in immunosuppressive mice models via regulation of the TLR4-NF-κB pathway

The immunoregulatory effect of a novel Craterellus cornucopioides polysaccharide (CCP) with a triple-helix structure on immunosuppressive BALB/c mice models was investigated; moreover, the immune response of BALB/c mice models in the preventive and therapeutic treatment groups treated with CCP was explored, and its molecular mechanism was elucidated. It was found that the BALB/c mice models in the preventive groups treated with CCP (120 and 240 mg kg^-1 d^-1) had better immunoregulatory activity. The spleen and thymus weight indices of the BALB/c mice models were significantly increased, and the histopathological analysis indicated a protective function of CCP against the immunosuppression induced by cyclophosphamide (CTX). Moreover, CCP displayed definite and clear synergistic effects on the T- or B-lymphocyte proliferation induced by ConA or LPS, respectively, promoted the natural killer (NK) cell activity and significantly increased phagocytic activity to activate peritoneal macrophages in immunosuppressive mice. The western blot and quantitative real-time polymerase chain reaction (qRT-PCR) results provided comprehensive evidence that CCP could upregulate the protein expression of the G-protein-coupled cell membrane receptor TLR4 and the production of its downstream protein kinases (TRAF6, TK1, p-IKKα/β and NF-κB p50); this, in turn, enhanced the production of cytokines (IL-2, IL-6, TNF-α and IFN-α) through both preventive and therapeutic treatments via regulation of the TLR4-NFκB pathway in the peritoneal macrophage of immunosuppressive mice.

Structure characterization, physicochemical property and immunomodulatory activity on RAW264.7 cells of a novel triple-helix polysaccharide from Craterellus cornucopioides

In the study, a new triple-helix polysaccharide with favorable stability was purified from C. cornucopioides. Its structural characterization, stability and solution behavior were investigated by the GC-MS, periodate oxidation-smith degradation, FT-IR, 1D and 2D NMR spectroscopy, methylation analysis, Scanning electron microscope, Congo-red, CD, TGA and DSC analysis. The results showed that Craterellus cornucopioide polysaccharide (CCP) possessed the molecular weight of 1.97 × 10³ kDa, is mainly composed of mannose (48.73%), galactose (17.37%), glucose (15.97%) and xylose (17.93%), respectively. It was a heteroglycan with (1 → 3)‑linked‑β‑d‑Manp‑(1 → 6)‑linked α‑d‑Galp backbone distributed by (1 → 4)‑linked‑α‑d‑Xylp‑t‑α‑d‑Manp and t‑β‑d‑Glup units at O-6. The result of TGA and DSC assay indicated that CCP has a favorable thermal stability. MTT and Scanning electro microscopy (SEM) assay showed that CCP could significantly improve the proliferation activity and induce cells activation of RAW264.7 in a certain range of concentrations and period.

Mitogen-activated protein kinase phosphatase 1 reduces the replication efficiency of Bamboo mosaic virus in Nicotiana benthamiana

In plants, the mitogen-activated protein kinase (MAPK) cascades are the central signaling pathways of the complicated defense network triggered by the perception of pathogen-associated molecular patterns to repel pathogens. The Arabidopsis thaliana MAPK phosphatase 1 (AtMKP1) negatively regulates the activation of MAPKs. Recently, the AtMKP1 homolog of Nicotiana benthamiana (NbMKP1) was found in association with the Bamboo mosaic virus (BaMV) replication complex. This study aimed to investigate the role of NbMKP1 in BaMV multiplication in N. benthamiana. Silencing of NbMKP1 increased accumulations of the BaMV-encoded proteins and the viral genomic RNA, although the same condition reduced the infectivity of Pseudomonas syringae pv. tomato DC3000 in N. benthamiana. On the other hand, overexpression of NbMKP1 decreased the BaMV coat protein accumulation in a phosphatase activity-dependent manner in protoplasts. NbMKP1 also negatively affected the in vitro RNA polymerase activity of the BaMV replication complex. Collectively, the activity of NbMKP1 seems to reduce BaMV multiplication, inconsistent with the negatively regulatory role of MKP1 in MAPK cascades in terms of warding off fungal and bacterial invasion. In addition, silencing of NbMKP1 increased the accumulation of Foxtail mosaic virus but decreased Potato virus X. The discrepant effects exerted by NbMKP1 on different pathogens foresee the difficulty to develop plants with broad-spectrum resistance through genetically manipulating a single player in MAPK cascades.

Galangin Induces p53-independent S-phase Arrest and Apoptosis in Human Nasopharyngeal Carcinoma Cells Through Inhibiting PI3K-AKT Signaling Pathway

BACKGROUND/AIM

Anti-cancer activity of 3,5,7-trihydroxyflavone (galangin) has been documented in a variety of cancer types; however, its effect on human nasopharyngeal carcinoma (NPC) cells remains undetermined.

MATERIALS AND METHODS

Human NPC cell lines were treated with galangin. Apoptosis was analyzed by assessing nuclear condensation, cleavage of pro-caspase-3 and poly ADP-ribose polymerase (PARP), and DNA fragmentation. Short hairpin RNA-mediated silencing of p53 was used for characterizing the role of p53 in the anti-cancer activity of galangin. Phosphatidylinositol 3-kinase (PI3K) inhibitor, protein kinase B (AKT) inhibitor, and ectopic expression of wild type p85α or p85α mutant lacking p110α-binding ability were utilized to confirm the involvement of PI3K/AKT inactivation in galangin-induced apoptosis.

RESULTS

Galangin induces apoptosis and S-phase arrest by attenuating the PI3K/AKT signaling pathway. Silencing of p53 did not block the anti-cancer activity of galangin on NPC cells.

CONCLUSION

Galangin effects on apoptosis and S-phase arrest in NPC cells are mediated via interfering with the PI3K-AKT signaling pathway in a p53-independent manner.

[Investigation of sagittal root position in relation to the anterior maxillary alveolar bone: a cone-beam CT study in 300 cases with normal occlusion]

Objective: To investigate the sagittal root position and apical bone height of the maxillary anterior teeth in order to provide anatomical information for immediate implant placement in the esthetic region. Methods: Cone-beam CT (CBCT) data from 300 randomly selected patients who met the inclusion criteria were included in this study. After three-dimensional reconstruction, the sagittal plane (the sagittal plane through the long axis of the tooth) was determined. The positions and angulations of the tooth roots were classified with reference to the alveolar process. By comparing the buccal and palatal bone thickness at the mid-root level, the toot positions with reference to the mid-alveolar line were defined and classified as follows, type B (closer to the buccal alveolar surface), type M (midway between the buccal and palatal alveolar surface) and type P (closer to the palatal alveolar surface). By comparing the angulations of the alveolar process with the long axis of the roots, the angulations were classified as follows, type 1 (root apex angulated toward the palatal side or parallel to the alveolus), type 2 (root apex angulated toward the buccal side with the long axis passing posterior to point A) and type 3 (root apex angulated toward the buccal side with the long axis passing anterior to point A). The frequency of each category was counted and the apical bone height was measured. The subjects were divided into three age groups, 19-30 years, 31-50 years and 51-75 years. Results: The overall mean apical bone height of the healthy maxillary central incisors was (9.2±3.0) mm, the lateral incisors was (10.0±2.9) mm and the canine was (8.1±3.1) mm. There was no significant difference in the height of apical bone between central incisors and lateral incisors (P>0.05). There was no significant difference in the height of apical bone between male and female (P>0.05). The height of apical bone in group 31-50 years and 51-75 years were greater than that in group 19-30 years (P<0.05), respectively. The proportion of the maxillary anterior teeth type B, M, P was 98.5% (1 774/1 800), 0.3% (5/1 800) and 1.2% (21/1 800) respectively. The proportion of type 1, 2, 3 was 2.6% (46/1 800), 58.6% (1 055/1 800) and 38.8% (699/1 800) respectively. Conclusions: There was enough apical bone height in the area of maxillary anterior teeth, but the majority of roots positioned more buccally.

Function and Structural Organization of the Replication Protein of Bamboo mosaic virus

The genus Potexvirus is one of the eight genera belonging to the family Alphaflexiviridae according to the Virus Taxonomy 2015 released by International Committee on Taxonomy of Viruses (www.ictvonline.org/index.asp). Currently, the genus contains 35 known species including many agricultural important viruses, e.g., Potato virus X (PVX). Members of this genus are characterized by flexuous, filamentous virions of 13 nm in diameter and 470-580 nm in length. A potexvirus has a monopartite positive-strand RNA genome, encoding five open-reading frames (ORFs), with a cap structure at the 5' end and a poly(A) tail at the 3' end. Besides PVX, Bamboo mosaic virus (BaMV) is another potexvirus that has received intensive attention due to the wealth of knowledge on the molecular biology of the virus. In this review, we discuss the enzymatic activities associated with each of the functional domains of the BaMV replication protein, a 155-kDa polypeptide encoded by ORF1. The unique cap formation mechanism, which may be conserved across the alphavirus superfamily, is particularly addressed. The recently identified interactions between the replication protein and the plant host factors are also described.

Bronchopleural fistula after lung ablation: Experience in two cases and literature review

BACKGROUND

Bronchopleural fistula (BPF) complicating lung tumor ablation is rare but severe. The purpose of this article was to study its characteristics and treatments.

MATERIALS AND METHODS

Two of 682 (0.3%) sessions of lung microwave ablation (MWA) were complicated with BPF and documented. Two electronic databases were searched for reported cases of BPF after lung tumor ablation. Case selection and data collection were done by 3 independent reviewers.

RESULTS

A 56-year-old man and a 61-year-old woman developed BPF after MWA and died. Thirteen cases (mean age 63.8, 61.5% male) of BPF with adequate information were identified from 8 articles. Of the 13 cases, 5 (38.5%) had pulmonary co-morbidity, 3 (23.1%) had a history of pulmonary surgery, 7 (53.8%) had a target tumor adjacent or abutting pulmonary pleura, and 6 (46.2%) developed severe infections. After chest tube placement, pleurodesis, endoscopic therapy, surgery, and other treatments, 12 were cured and 1 died of BPF and pneumonia.

CONCLUSION

BPF is a rare but severe complication of lung ablation, and the management needs a multidisciplinary and individualized treatment strategy.

Association between monoamine oxidase B A644G polymorphism and Parkinson's disease risk: a meta-analysis in the Chinese population

Although various individual studies have evaluated the correlation between monoamine oxidase B (MAOB), polymorphism, and Parkinson's disease (PD), the results remain inconclusive. Therefore, we performed a meta-analysis in the Chinese population to provide comprehensive data on the association between the MAOB polymorphism and PD. Eligible studies were identified via databases such as PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure, and Chinese Biology Medicine, throughout November 2015. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strengths of these associations. Eight studies documenting a total of 1385 cases of PD and 1426 controls were included in this meta-analysis. Overall, no significant association was found between the MAOB A644G polymorphism and PD risk in the Chinese population. However, in subgroup analyses, where results were stratified by geographical areas and source of controls, increased risk for PD in Northern China was observed (allele A vs G: OR = 1.33, 95%CI = 1.11-1.58; AA vs GG: OR = 1.46, 95%CI = 1.09-1.97; AA + AG vs GG: OR = 1.42, 95%CI = 1.06-1.90). Similarly, population-based studies also showed significant association between the MAOB A644G polymorphism and PD risk among different populations (allele A vs G: OR = 1.29, 95%CI = 1.11-1.51; AA vs GG: OR = 1.41, 95%CI = 1.09-1.82; AA + AG vs GG: OR = 1.34, 95%CI = 1.04- 1.71). In conclusion, this meta-analysis provided evidence that the MAOB A644G polymorphism may contribute to PD development in Northern China. Further studies conducted in other ethnic groups are required for definite conclusions.

Shp2 suppresses the adipogenic differentiation of preadipocyte 3T3-L1 cells at an early stage

Tyrosine phosphatase protein Shp2 is a potential therapeutic target for obesity. However, the mechanism of Shp2 during adipogenesis is not fully understood. The present study investigated the role of Shp2 in the terminal differentiation of preadipocytes. The results showed that Shp2 suppressed adipocyte differentiation in 3T3-L1 cells; overexpression of Shp2 reduced lipid droplet production in 3T3-L1 cells, whereas Shp2 knockdown increased lipid droplet production in 3T3-L1 cells. Furthermore, inhibition of Shp2 activity also enhanced adipocyte differentiation. Interestingly, Shp2 expression was specifically decreased early during differentiation in response to stimulation with the dexamethasone–methylisobutylxanthine–insulin (DMI) hormone cocktail. During the first 2 days of differentiation, Shp2 overexpression impaired the DMI-induced phosphorylation of signal transducer and activator of transcription 3 (STAT3) in 3T3-L1 cells and blocked the peak expression of CCAAT/enhancer-binding proteins β and δ during preadipocyte differentiation. In conclusion, Shp2 downregulated the early stages of hormone-induced differentiation of 3T3-L1 cells and inhibited the expression of the first wave of transcription factors by suppressing the DMI-induced STAT3 signaling pathway. These discoveries point to a novel role of Shp2 during adipogenesis and support the hypothesis that Shp2 could be a therapeutic target for the control of obesity.

Artificial pneumothorax for pain relief during microwave ablation of subpleural lung tumors

BACKGROUND

When microwave ablation (MWA) is used for subpleural lesions, severe pain was the common side effect under the local anesthesia conditions during the procedure and postprocedure. To study the pain relief effect of artificial pneumothorax in the treatment of subpleural lung tumors with MWA.

MATERIALS AND METHODS

From February 2012 to October 2014, 37 patients with 40 subpleural lung tumors underwent MWA, including 17 patients of 19 sessions given artificial pneumothorax prior to MWA (group-I), and 20 patients of 21 sessions without artificial pneumothorax (group-II). Patient's pain assessment scores (10-point visual analog scale [VAS]) at during-procedure, 6, 12, 24, and 48 h after the MWA procedure and mean 24 h morphine dose were compared between the two groups. Complications of the artificial pneumothorax were also summarized.

RESULTS

Pain VAS were 0.53, 0.65, 1.00, 0.24, and 0.18 at during-procedure, 6, 12, 24, and 48 h for group-I and 5.53, 2.32, 2.82, 1.21, and 0.21 for group-II, respectively. Pain VAS in group I was significantly decreased at during-procedure, 6, 12, and 24 h after the MWA (P < 0.001). No statistical pain VAS difference was observed at 48 h after the MWA between the two groups (P > 0.05). The mean 24 h morphine dose was 5.00 mg in group-I and 12.63 mg in group-II (P = 0.000). "Artificial pneumothorax" related complications occurred in two patients from group-I, including one pleural effusion and one minor hemoptysis. No patient in group-I and group-II died during the procedure or in 30 days after MWA.

CONCLUSION

Artificial pneumothorax is a safe and effective method for pain relief during MWA of subpleural lung tumors.

Promotion of Bamboo Mosaic Virus Accumulation in Nicotiana benthamiana by 5'→3' Exonuclease NbXRN4

Bamboo mosaic virus (BaMV) has a 6.4-kb (+) sense RNA genome with a 5' cap and a 3' poly(A) tail. ORF1 of this potexvirus encodes a 155-kDa replication protein responsible for the viral RNA replication/transcription and 5' cap formation. To learn more about the replication complex of BaMV, a protein preparation enriched in the 155-kDa replication protein was obtained from Nicotiana benthamiana by a protocol involving agroinfiltration and immunoprecipitation. Subsequent analysis by SDS-PAGE and mass spectrometry identified a handful of host proteins that may participate in the viral replication. Among them, the cytoplasmic exoribonuclease NbXRN4 particularly caught our attention. NbXRN4 has been shown to have an antiviral activity against Tomato bushy stunt virus and Tomato mosaic virus. In Arabidopsis, the enzyme could reduce RNAi- and miRNA-mediated RNA decay. This study found that downregulation of NbXRN4 greatly decreased BaMV accumulation, while overexpression of NbXRN4 resulted in an opposite effect. Mutations at the catalytically essential residues abolished the function of NbXRN4 in the increase of BaMV accumulation. Nonetheless, NbXRN4 was still able to promote BaMV accumulation in the presence of the RNA silencing suppressor P19. In summary, the replication efficiency of BaMV may be improved by the exoribonuclease activity of NbXRN4.

Supplement of 5-hydroxytryptophan before induction suppresses inflammation and collagen-induced arthritis

Background

Evidence is accumulating that a preclinical phase is present before the onset of clinical signs and symptoms of rheumatoid arthritis (RA). This phase represents an important therapeutic window within which interventions can dramatically modulate outcomes. An agent able to prevent RA for high risk individuals in this phase is therefore desired. In this study, we investigated whether tryptophan metabolite, 5-hydroxytryptophan (5-HTP) or 5-methoxytryptophan (5-MTP), can act as such an agent for primary prevention of collagen-induced arthritis (CIA).

Methods

Mouse splenocytes were pretreated with 5-HTP or 5-MTP and activated by anti-CD3 plus anti-CD28 antibodies in vitro. The percentages of interferon-γ (IFNγ)⁺CD4⁺ T cells and interleukin-17 (IL-17)⁺CD4⁺ T cells were measured by flow cytometry. The production of pro-inflammatory cytokines, serotonin and kynurenine was measured by enzyme-linked immunosorbent assay. A CIA model was used to investigate the in vivo effects of 5-HTP on the prevention of arthritis.

Results

5-HTP decreased the percentages of IFNγ⁺CD4⁺ T cells and IL-17⁺CD4⁺ T cells and suppressed the production of IL-2, IL-4, IL-6, IL-17, tumor necrosis factor-α (TNFα) and IFNγ in activated splenocytes. 5-HTP administered before induction decreased the disease activities in CIA mice and suppressed the production of TNFα, IL-6 and cyclooxygenase-2 in arthritic joints. 5-HTP also increased serotonin, but decreased kynurenine in the CIA mice.

Conclusions

5-HTP suppresses inflammation and arthritis through decreasing the production of pro-inflammatory mediators. 5-HTP supplement before induction ameliorates arthritis in a CIA model.

Isolation, characterization, and complete genome analysis of P1312, a thermostable bacteriophage that infects Thermobifida fusca

Thermobifida fusca is a moderately thermophilic and cellulolytic actinobacterium. It is of particular interest due to its ability to not only produce a variety of biotechnologically relevant enzymes but also serve as an alternative host for metabolic engineering for the production of valuable chemicals from lignocellulosic agricultural wastes. No bacteriophage that infects T. fusca has been reported, despite its potential impacts on the utilization of T. fusca. In this study, an extremely thermostable bacteriophage P1312 that infects T. fusca was isolated from manure compost. Electron microscopy showed that P1312 has an icosahedral head and a long flexible non-contractile tail, a characteristic of the family Siphoviridae. P1312 has a double-stranded DNA genome of 60,284 bp with 93 potential ORFs. Thirty-one ORFs encode proteins having putative biological functions. The genes involved in phage particle formation cluster together in a region of approximately 16 kb, followed by a segment containing genes presumably for DNA degradation/modification and cell wall disruption. The genes required for DNA replication and transcriptional control are dispersed within the rest of the genome. Phylogenetic analysis of large terminase subunit suggests that P1312 is a headful packaging phage containing a chromosome with circularly permuted direct terminal repeats.

A novel binding of GTP stabilizes the structure and modulates the activities of human phosphoglucose isomerase/autocrine motility factor

Phosphoglucose isomerase (PGI) catalyzes the interconversion between glucose 6-phosphate and fructose 6-phosphate in the glycolysis pathway. In mammals, the enzyme is also identical to the extracellular proteins neuroleukin, tumor-secreted autocrine motility factor (AMF) and differentiation and maturation mediator for myeloid leukemia. Hereditary deficiency of the enzyme causes non-spherocytic hemolytic anemia in human. In the present study, a novel interaction between GTP and human PGI was corroborated by UV-induced crosslinking, affinity purification and kinetic study. GTP not only inhibits the isomerization activity but also compromises the AMF function of the enzyme. Kinetic studies, including the Yonetani-Theorell method, suggest that GTP is a competitive inhibitor with a K_i value of 63 μM and the GTP-binding site partially overlaps with the catalytic site. In addition, GTP stabilizes the structure of human PGI against heat- and detergent-induced denaturation. Molecular modelling and dynamic simulation suggest that GTP is bound in a syn-conformation with the γ-phosphate group located near the phosphate-binding loop and the ribose moiety positioned away from the active-site residues.

Phosphorylation of coat protein by protein kinase CK2 regulates cell-to-cell movement of Bamboo mosaic virus through modulating RNA binding

In this study, we investigated the fine regulation of cell-to-cell movement of Bamboo mosaic virus (BaMV). We report that the coat protein (CP) of BaMV is phosphorylated in planta at position serine 241 (S241), in a process involving Nicotiana benthamiana casein kinase 2α (NbCK2α). BaMV CP and NbCK2α colocalize at the plasmodesmata, suggesting that phosphorylation of BaMV may be involved in its movement. S241 was mutated to examine the effects of temporal and spatial dysregulation of phosphorylation on i) the interactions between CP and viral RNA and ii) the regulation of cell-to-cell movement. Replacement of S241 with alanine did not affect RNA binding affinity but moderately impaired cell-to-cell movement. A negative charge at position 241 reduced the ability of CP to bind RNA and severely interfered with cell-to-cell movement. Deletion of residues 240 to 242 increased the affinity of CP to viral RNA and dramatically impaired cell-to-cell movement. A threonine at position 241 changed the binding preference of CP toward genomic RNA and inhibited cell-to-cell movement. Together, these results reveal a fine regulatory mechanism for the cell-to-cell movement of BaMV, which involves the modulation of RNA binding affinity through appropriate phosphorylation of CP by NbCK2α.

Deletion of the gene encoding the reductase component of 3-ketosteroid 9α-hydroxylase in Rhodococcus equi USA-18 disrupts sterol catabolism, leading to the accumulation of 3-oxo-23,24-bisnorchola-1,4-dien-22-oic acid and 1,4-androstadiene-3,17-dione

The gene encoding the putative reductase component (KshB) of 3-ketosteroid 9α-hydroxylase was cloned from Rhodococcus equi USA-18, a cholesterol oxidase-producing strain formerly named Arthrobacter simplex USA-18, by PCR according to consensus amino acid motifs of several bacterial KshB subunits. Deletion of the gene in R. equi USA-18 by a PCR-targeted gene disruption method resulted in a mutant strain that could accumulate up to 0.58 mg/ml 1,4-androstadiene-3,17-dione (ADD) in the culture medium when 0.2% cholesterol was used as the carbon source, indicating the involvement of the deleted enzyme in 9α-hydroxylation of steroids. In addition, this mutant also accumulated 3-oxo-23,24-bisnorchola-1,4-dien-22-oic acid (Δ^1,4-BNC). Because both ADD and Δ^1,4-BNC are important intermediates for the synthesis of steroid drugs, this mutant derived from R. equi USA-18 may deserve further investigation for its application potential.