Development and validation of a machine learning-based nomogram for predicting HLA-B27 expression.

BACKGROUND: HLA-B27 positivity is normal in patients undergoing rheumatic diseases. The diagnosis of many diseases requires an HLA-B27 examination. METHODS: This study screened totally 1503 patients who underwent HLA-B27 examination, liver/kidney function tests, and complete blood routine examination in First Affiliated Hospital of Guangxi Medical University. The training cohort included 509 cases with HLA-B27 positivity whereas 611 with HLA-B27 negativity. In addition, validation cohort included 147 cases with HLA-B27 positivity whereas 236 with HLA-B27 negativity. In this study, 3 ML approaches, namely, LASSO, support vector machine (SVM) recursive feature elimination and random forest, were adopted for screening feature variables. Subsequently, to acquire the prediction model, the intersection was selected. Finally, differences among 148 cases with HLA-B27 positivity and negativity suffering from ankylosing spondylitis (AS) were investigated. RESULTS: Six factors, namely red blood cell count, human major compatibility complex, mean platelet volume, albumin/globulin ratio (ALB/GLB), prealbumin, and bicarbonate radical, were chosen with the aim of constructing the diagnostic nomogram using ML methods. For training queue, nomogram curve exhibited the value of area under the curve (AUC) of 0.8254496, and C-value of the model was 0.825. Moreover, nomogram C-value of the validation queue was 0.853, and the AUC value was 0.852675. Furthermore, a significant decrease in the ALB/GLB was noted among cases with HLA-B27 positivity and AS cases. CONCLUSION: To conclude, the proposed ML model can effectively predict HLA-B27 and help doctors in the diagnosis of various immune diseases.

Development of Schizochytrium sp. strain HS01 with high-DHA and low-saturated fatty acids production by multi-pronged adaptive evolution.

PURPOSE: Docosahexaenoic acid (DHA) is an important omega-3 unsaturated fatty acid and has been widely applied in medicine, food additives, and feed ingredients. The fermentative production of DHA using microorganisms, including Schizochytrium sp., attracted much attention due to its high production efficiency and environment friendly properties. An efficient laboratory evolution approach was used to improve the strain's performance in this study. METHODS: A multi-pronged laboratory evolution approach was applied to evolve high-yield DHA-producing Schizochytrium strain. We further employed comparative transcriptional analysis to identify transcriptional changes between the screened strain HS01 and its parent strain GS00. RESULTS: After multiple generations of ALE, a strain HS01 with higher DHA content and lower saturated fatty acids content was obtained. Low nitrogen conditions were important for enhancing DHA biosynthesis in HS01. The comparative transcriptional analysis results indicated that during the fermentation process of HS01, the expression of key enzymes in the glycolysis, the pentose phosphate pathway and the tricarboxylic acid cycle were up-regulated, while the expression of polyketide synthase genes and fatty acid synthesis genes were similar to those in GS00. CONCLUSION: The results suggest that the improved DHA production capacity of HS01 is not due to enhancement of the DHA biosynthesis pathway, but rather related to modulation of central metabolism pathways.

Application of machine learning in prediction of bone cement leakage during single-level thoracolumbar percutaneous vertebroplasty.

BACKGROUND: In the elderly, osteoporotic vertebral compression fractures (OVCFs) of the thoracolumbar vertebra are common, and percutaneous vertebroplasty (PVP) is a common surgical method after fracture. Machine learning (ML) was used in this study to assist clinicians in preventing bone cement leakage during PVP surgery. METHODS: The clinical data of 374 patients with thoracolumbar OVCFs who underwent single-level PVP at The First People's Hospital of Chenzhou were chosen. It included 150 patients with bone cement leakage and 224 patients without it. We screened the feature variables using four ML methods and used the intersection to generate the prediction model. In addition, predictive models were used in the validation cohort. RESULTS: The ML method was used to select five factors to create a Nomogram diagnostic model. The nomogram model's AUC was 0.646667, and its C value was 0.647. The calibration curves revealed a consistent relationship between nomogram predictions and actual probabilities. In 91 randomized samples, the AUC of this nomogram model was 0.7555116. CONCLUSION: In this study, we invented a prediction model for bone cement leakage in single-segment PVP surgery, which can help doctors in performing better surgery with reduced risk.

Anti-proliferative tirucallane triterpenoids from gum resin of Boswellia sacra.

Eight new tirucallane triterpenoids (1-2, 5-10) along with two known compounds (3-4) were isolated from the gum resin of Boswellia sacra. Their structures were elucidated by extensive physicochemical and spectroscopic analysis, as well as computational calculations, and single crystal X-ray diffraction. Spirosacraoic acid A (1) and B (2), possess an unusual 6/5/6/5 rearranged spirocyclic carbon skeleton. All the isolates were evaluated for their anti-proliferative activity against two tumor cell lines (HepG2 and HCT-116 cells). Compound 10 displayed remarkable inhibitory activity against HepG2 cells in a dose-dependent manner with the IC50 value of 28.01 µM. High content analysis (HCA) showed that 10 induces apoptosis in HepG2 cells. The western blotting results revealed that 10 could up-regulate the ratio of the expression of Bax/BCL-2, and promote the caspase 3 activation and PARP cleavage. Mechanically, molecular modeling studies demonstrated that 10 could dock into EGFR active site. Meanwhile 10 significantly decreased the protein expression of p-EGFR. Furthermore, inhibition of EGFR by addition of EGFR siRNA enhanced the growth inhibitory effects of 10 on HepG2 cells, indicating that the anti-tumor effect of 10 on HepG2 cells was mediated by inhibition of EGFR.

Pulmonary embolism following the third thoracic tuberculosis surgery: A case report and literature review.

BACKGROUND: The study aimed to analyze the clinical effects of pulmonary embolism succeeding a third surgery conducted for multiple recurrences in thoracic tuberculosis (TB). CASE REPORT: A 74-year-old female patient developed thoracic tuberculosis and was subsequently treated in our hospital in March 2019, October 2020, and February 2021. The third surgical intervention included anterolateral thoracic lesion resection, internal fixation, posterior spinal tuberculous sinus resection, and debridement with suture. The operative time was 172 min resulting in a substantial intraoperative blood loss (2321 ml). Postoperative re-examination of chest CTPA indicated a strip filling defect and pulmonary embolism in the external branch of the right middle lobe of the lung. After completing the active treatment, the D-dimer quantification, WBC, CRP, and ESR values were 1261 ng/ml, 7.71 × 109 /L, 74.66 mg/L, and 63 mm, respectively. Chest CTPA re-examination after the treatment showed no signs of pulmonary embolism. CONCLUSION: Patients with a long-term history of multiple operations, high BMI, cerebral infarction, diabetes, and older age group were more likely to develop pulmonary embolism after spinal tuberculosis surgery. Thus, the possibility of postoperative pulmonary embolism should be thoroughly analyzed before any subsequent surgical treatment in patients with recurrent spinal tuberculosis.

Suitability of 3.5-mm screw for the atlas in children: a retrospective computed tomography analysis.

BACKGROUND: The growth and development of the atlas in children has not been studied to date using a large sample size. OBJECTIVE: To study whether a 3.5-mm screw is suitable for the atlas in children, to explore the anatomical size and development of the atlas in 0-14-year-old children, and to provide morphological basis for lateral mass screw internal fixation. METHODS: A Computed Tomography (CT) morphometric analysis was performed on 420 pediatric atlases. In the atlas, D1, D2, D3, D4, and α of the atlas lateral mass were measured. Statistical analysis was performed using one-way ANOVA and Students' t test. The least square method was used for the regression analysis of the change trend in anatomical structure. The curve with the greatest goodness of fit was used as the anatomic trend regression curve. RESULTS: D1, D2, D3, and D4 generally showed an increasing trend with age. The ranges of averages of D1, D2, D3, D4, and α in 0-14 year-old children were as follows: 4.576-9.202 mm, 9.560-25.100 mm, 3.414-10.554 mm, 11.150-27.895, and 12.41°-20.97°, respectively. The trends of the fitting curves of L1 and L3 were power functions, and those of L2 and L4 were logarithmic curves. CONCLUSIONS: CT examination could help in preoperative decision-making, and 3.5-mm screw was found to be suitable for lateral mass screw internal fixation in children aging 2 years and older. D1-D4 increased with age. This provided a certain reference to perform posterior atlantoaxial fusion in children and is of great significance to design posterior atlantoaxial screw in children.

Blood transfusion risk prediction in spinal tuberculosis surgery: development and assessment of a novel predictive nomogram.

OBJECTIVE: The present study attempted to predict blood transfusion risk in spinal tuberculosis surgery by using a novel predictive nomogram. METHODS: The study was conducted on the clinical data of 495 patients (167 patients in the transfusion group and 328 patients in the non-transfusion group) who underwent spinal tuberculosis surgery in our hospital from June 2012 to June 2021. The least absolute shrinkage and selection operator (LASSO) and multivariable logistic regression analyses were used to screen out statistically significant parameters, which were included to establish a novel predictive nomogram model. The receiver operating characteristic (ROC) curve, calibration curves, C-index, and decision curve analysis (DCA) were used to evaluate the model. Finally, the nomogram was further assessed through internal validation. RESULTS: The C-index of the nomogram was 0.787 (95% confidence interval: 74.6%-.82.8%). The C-value calculated by internal validation was 0.763. The area under the curve (AUC) of the predictive nomogram was 0.785, and the DCA was 0.01-0.79. CONCLUSION: A nomogram with high accuracy, clinical validity, and reliability was established to predict blood transfusion risk in spinal tuberculosis surgery. Surgeons must prepare preoperative surgical strategies and ensure adequate availability of blood before surgery.

Characterization of Pasteurella multocida isolated from ducks in China from 2017 to 2019.

Pasteurella multocida, an important gram-negative pathogen that mainly inhibits the upper respiratory tracts of domestic and wild animals such as chicken, duck, cattle and pig, which can cause cholera fowl, haemorrhagic septicaemia and infectious pneumonia. Currently, the prevalence and infection of P.multocida is still one of the most serious threats to the poultry industry in China, but studies on its characteristics are still insufficient. Here, this study was conducted to isolate and identify P.multocida in infected ducks and determined the leading serotypes and epidemiology of the diseases this pathogen causes. Results indicated that all the isolates were positive for KMT1 gene and the PCR amplified products were approximately 460 bp, demonstrating that these strains were all P.multocida. Moreover, all the isolated strains were identified as capsular type A and lipopolysaccharide type L1. Virulence factor identification results revealed that all strains possessed genes related to pili, adhesin, iron metabolism and uptake. In contrast, toxin coding gene (toxA) and sialidase encodes genes (nan B and nan H) were not detected in any isolates. The drug susceptibility results indicated that all the isolates were resistant to Lincomycin, Chloramphenicol, Clindamycin and Oxacillin but were sensitive to Ceftriaxone and Cefalotin. The animal experiments were also performed to further determine the pathogenicity of these isolated strains. Animal experiment revealed that the liver, kidney, and heart of infected ducks were swollen and had bleeding spots. We also observed hepatocyte hypertrophy, hepatic sinus congestion and single-cell infiltration in infected ducks through H&E staining. In summary, this study demonstrated that all the isolated strains belong to capsular A and lipopolysaccharide type L1 P.multocida, but their virulence factors, drug resistance and pathogenicity were different.

A Retrospective Study of Factors Associated with Restoration of Thoracic Kyphosis in 43 Patients with Adolescent Idiopathic Scoliosis with Lenke Type 1 Curvature.

BACKGROUND This retrospective study aimed to identify the factors associated with successful surgical correction of thoracic kyphosis (TK) in 43 patients with adolescent idiopathic scoliosis (AIS) with Lenke type 1 curvature, in which the major curve with the largest Cobb angle was mainly in the thoracic region. MATERIAL AND METHODS We collected data from patients with Lenke 1 AIS. The following parameters were measured: Cobb angle, side-bending Cobb angle, cervical lordosis (CL), TK, lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), the sagittal vertical axis (SVA), the center of a C7 plumb line to the center sacral vertical line (C7-CSVL), correction rate, Ponte osteotomy, flexibility, and screw density. Univariate analysis and multivariate logistic regression analyses were performed. RESULTS Among the 43 cases analyzed, the mean postoperative Cobb angle at the last follow-up, C7-CSVL, SVA, CL, TK, LL, PI, SS, and PT were respectively 21.33±9.47°, 10.41±8.45 mm, 19.68±14.33 mm, 16.19±7.45°, 23.12±7.45°, 50.33±11.37°, 49.70±9.83°, 39.42±8.11°, and 10.16±6.63°. Univariate analysis suggested that preoperative TK, preoperative LL, and Ponte osteotomy were statistically significant (P<0.05), and multivariate analysis suggested that preoperative LL and Ponte osteotomy were statistically significant (P<0.05). CONCLUSIONS The results of this study demonstrated that preoperative TK, preoperative LL, and Ponte osteotomy were related factors for maintaining normal TK. Multivariate analysis suggested that preoperative LL and the use of Ponte osteotomy with full-thickness segmental resection of the spinal posterior column resulted in the successful surgical correction of TK in patients with AIS with Lenke type 1 curvature.

The N-Terminal Region of Soybean PM1 Protein Protects Liposomes during Freeze-Thaw.

Late embryogenesis abundant (LEA) group 1 (LEA_1) proteins are intrinsically disordered proteins (IDPs) that play important roles in protecting plants from abiotic stress. Their protective function, at a molecular level, has not yet been fully elucidated, but several studies suggest their involvement in membrane stabilization under stress conditions. In this paper, the soybean LEA_1 protein PM1 and its truncated forms (PM1-N: N-terminal half; PM1-C: C-terminal half) were tested for the ability to protect liposomes against damage induced by freeze-thaw stress. Turbidity measurement and light microscopy showed that full-length PM1 and PM1-N, but not PM1-C, can prevent freeze-thaw-induced aggregation of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) liposomes and native thylakoid membranes, isolated from spinach leaves (Spinacia oleracea). Particle size distribution analysis by dynamic light scattering (DLS) further confirmed that PM1 and PM1-N can prevent liposome aggregation during freeze-thaw. Furthermore, PM1 or PM1-N could significantly inhibit membrane fusion of liposomes, but not reduce the leakage of their contents following freezing stress. The results of proteolytic digestion and circular dichroism experiments suggest that PM1 and PM1-N proteins bind mainly on the surface of the POPC liposome. We propose that, through its N-terminal region, PM1 functions as a membrane-stabilizing protein during abiotic stress, and might inhibit membrane fusion and aggregation of vesicles or other endomembrane structures within the plant cell.

Efficient synthesis of piperazinyl amides of 18ß-glycyrrhetinic acid.

In the present study, a practical method to prepare piperazinyl amides of 18ß-glycyrrhetinic acid was developed. Two main procedures for the construction of important intermediate 8 are discussed. One procedure involves the amidation of 1-Boc-piperazine with 3-acetyl-18ß-glycyrrhetinic acid, prepared by the reaction of 18ß-glycyrrhetinic acid with acetic anhydride without any solvent at 130 °C. The other procedure to prepare compound 8 involves the amidation of 18ß-glycyrrhetinic acid followed by the esterification with acetic anhydride. Finally, compound 8 underwent N-Boc deprotection to prepare product 4. To ascertain the scope of the reaction, another C-3 ester derivative 17 was tested under the optimized reaction conditions. Furthermore, the reasons for the appearance of byproducts were elucidated. Crystallographic data of a selected piperazinyl amide is reported.

Effects of high-power ultrasound on microflora, enzymes and some quality attributes of a strawberry drink.

BACKGROUND: The objective of the present work was to study the effect of high-power ultrasound (HPU) on the microflora, enzymes and some quality attributes of a strawberry drink and to provide a theoretical basis for strawberry drink processing conducive to the development of more nutritious and healthier strawberry drinks. RESULTS: Fresh strawberry drink was subjected to HPU treatment at 20 kHz (242, 605 and 968 W cm-2 ) for 2, 4, 6, 8 and 10 min in an ice bath. Results showed that polyphenol oxidase (PPO), pectin methyl esterase (PME) and ß-glucosidase activities were decreased by 44.90, 89.11 and 84.71% respectively at 968 W cm-2 for 10 min. Lower L*, a* and b* values and higher browning degree (BD) were observed in HPU-treated samples, resulting in a significant increase in ΔE value (P < 0.05). HPU treatment caused loss of viscosity and turbidity, while total soluble solids (TSS) and pH of the strawberry drink were stable. Total phenol content and antioxidant capacity increased while anthocyanin content decreased compared with untreated samples. Total aerobic bacteria (TAB) and molds and yeasts (M&Y) were reduced by 2.07 and 1.13 log10 cycles respectively at 968 W cm-2 for 10 min. CONCLUSIONS: HPU can effectively achieve the effect of pasteurization and maintain the nutrients of strawberry drink. © 2018 Society of Chemical Industry.

Clarification of the molecular pathway of Taiwan local pomegranate fruit juice underlying the inhibition of urinary bladder urothelial carcinoma cell by proteomics strategy.

BACKGROUND: Pomegranate fruit has been shown to exhibit the inhibitory activity against prostate cancer and lung cancer in vitro and in vivo, which might be a resource for chemoprevention and chemotherapy of cancer. Our previous documented findings indicated that treatment of urinary bladder urothelial carcinoma cell with the ethanol extract isolated from the juice of pomegranate fruit grown in Taiwan could inhibit tumor cell. In this study we intended to uncover the molecular pathway underlying anti-cancer efficacy of Taiwan pomegranate fruit juice against urinary bladder urothelial carcinoma. METHODS: We exploited two-dimensional gel electrophoresis coupled with tandem mass spectrometry to find the de-regulated proteins. Western immunoblotting was used to confirm the results collected from proteomics study. RESULTS: Comparative proteomics indicated that 20 proteins were differentially expressed in ethanol extract-treated T24 cells with 19 up-regulated and 1 down-regulated proteins. These de-regulated proteins were involved in apoptosis, cytoskeleton regulation, cell proliferation, proteasome activity and aerobic glycolysis. Further studies on signaling pathway demonstrated that ethanol extract treatment might inhibit urinary bladder urothelial carcinoma cell proliferation through restriction of PTEN/AKT/mTORC1 pathway via profilin 1 up-regulation. It also might evoke cell apoptosis through Diablo over-expression. CONCLUSIONS: The results of this study provide a global picture to further investigate the anticancer molecular mechanism of pomegranate fruit.

Trigeminal nerve direct current stimulation causes sustained increase in neural activity in the rat hippocampus.

BACKGROUND: Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation method that can modulate many brain functions including learning and memory. Recent evidence suggests that tDCS memory effects may be caused by co-stimulation of scalp nerves such as the trigeminal nerve (TN), and not the electric field in the brain. The TN gives input to brainstem nuclei, including the locus coeruleus that controls noradrenaline release across brain regions, including hippocampus. However, the effects of TN direct current stimulation (TN-DCS) are currently not well understood. HYPOTHESIS: In this study we tested the hypothesis that stimulation of the trigeminal nerve with direct current manipulates hippocampal activity via an LC pathway. METHODS: We recorded neural activity in rat hippocampus using multichannel silicon probes. We applied 3 min of 0.25 mA or 1 mA TN-DCS, monitored hippocampal activity for up to 1 h and calculated spikes-rate and spike-field coherence metrics. Subcutaneous injections of xylocaine were used to block TN, while intraperitoneal and intracerebral injection of clonidine were used to block the LC pathway. RESULTS: We found that 1 mA TN-DCS caused a significant increase in hippocampal spike-rate lasting 45 min in addition to significant changes in spike-field coherence, while 0.25 mA TN-DCS did not. TN blockage prevented spike-rate increases, confirming effects were not caused by the electric field in the brain. When 1 mA TN-DCS was delivered during clonidine blockage no increase in spike-rate was observed, suggesting an important role for the LC-noradrenergic pathway. CONCLUSION: These results support our hypothesis and provide a neural basis to understand the tDCS TN co-stimulation mechanism. TN-DCS emerges as an important tool to potentially modulate learning and memory.

Guided isolation of enantiomeric lignans from Cimicifuga heracleifolia Kom. by antioxidant activity and molecular networking.

Under the guidance of antioxidant evaluation combined with molecular networking, six pairs of enantiomeric lignans including seven undescribed ones (1a, 2a/2b-4a/4b), along with five known analogs (1b, 5a/5b-6a/6b) were isolated from Cimicifuga heracleifolia Kom. Their structures were determined by extensive spectroscopic data analysis, including HRESIMS, 1D and 2D NMR, experimental and calculated ECD. All the enantiomeric isolates were evaluated for antioxidation by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2'-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging tests. Compounds 1a and 3a/3b exhibited great DPPH and ABTS scavenging activities. The results are of great value for understanding structurally interesting enantiomeric lignans with antioxidant activity from C. heracleifolia in depth and providing its further development in functional evaluation and drug development.

Age and flexors as risk factors for cervical radiculopathy: A new machine learning method.

This study aimed to investigate the risk factors for cervical radiculopathy (CR) along with identifying the relationships between age, cervical flexors, and CR. This was a retrospective cohort study, including 60 patients with CR enrolled between December 2018 and June 2020. In this study, we measured C2 to C7 Cobb angle, disc degeneration, endplate degeneration, and morphology of paraspinal muscles and evaluated the value of predictive methods using receiver operating characteristic curves. Next, we established a diagnostic model for CR using Fisher discriminant model and compared different models by calculating the kappa value. Age and cervical flexor factors were used to construct clinical predictive models, which were further evaluated by C-index, receiver operating characteristic curve, calibration curve, and decision curve analysis. Multivariate analysis showed that age and cervical flexors were potential risk factors for CR, while the diagnostic model indicated that both exerted the best diagnostic effect. The obtained diagnostic equation was as follows: y1 = 0.33 × 1 + 10.302 × 2-24.139; y2 = 0.259 × 1 + 13.605 × 2-32.579. Both the C-index and AUC in the training set reached 0.939. Moreover, the C-index and AUC values in the external validation set reached 0.961. We developed 2 models for predicting CR and also confirmed their validity. Age and cervical flexors were considered potential risk factors for CR. Our noninvasive inspection method could provide clinicians with a more potential diagnostic value to detect CR accurately.

Development and validation of a diagnostic model to differentiate spinal tuberculosis from pyogenic spondylitis by combining multiple machine learning algorithms.

This study focused on the development and validation of a diagnostic model to differentiate between spinal tuberculosis (STB) and pyogenic spondylitis (PS). We analyzed a total of 387 confirmed cases, out of which 241 were diagnosed with STB and 146 were diagnosed with PS. These cases were randomly divided into a training group (n = 271) and a validation group (n = 116). Within the training group, four machine learning (ML) algorithms (least absolute shrinkage and selection operator [LASSO], logistic regression analysis, random forest, and support vector machine recursive feature elimination [SVM-RFE]) were employed to identify distinctive variables. These specific variables were then utilized to construct a diagnostic model. The model's performance was subsequently assessed using the receiver operating characteristic (ROC) curves and the calibration curves. Finally, internal validation of the model was undertaken in the validation group. Our findings indicate that PS patients had an average platelet-to-neutrophil ratio (PNR) of 277.86, which was significantly higher than the STB patients' average of 69.88. The average age of PS patients was 54.71 years, older than the 48 years recorded for STB patients. Notably, the neutrophil-to-lymphocyte ratio (NLR) was higher in PS patients at 6.15, compared to the 3.46 NLR in STB patients. Additionally, the platelet volume distribution width (PDW) in PS patients was 0.2, compared to 0.15 in STB patients. Conversely, the mean platelet volume (MPV) was lower in PS patients at an average of 4.41, whereas STB patients averaged 8.31. Hemoglobin (HGB) levels were lower in PS patients at an average of 113.31 compared to STB patients' average of 121.64. Furthermore, the average red blood cell (RBC) count was 4.26 in PS patients, which was less than the 4.58 average observed in STB patients. After evaluation, seven key factors were identified using the four ML algorithms, forming the basis of our diagnostic model. The training and validation groups yielded area under the curve (AUC) values of 0.841 and 0.83, respectively. The calibration curves demonstrated a high alignment between the nomogram-predicted values and the actual measurements. The decision curve indicated optimal model performance with a threshold set between 2% and 88%. In conclusion, our model offers healthcare practitioners a reliable tool to efficiently and precisely differentiate between STB and PS, thereby facilitating swift and accurate diagnoses.

Exosomal circ_CCDC7/gga-miR-6568-3p/Pax7 axis accelerates the differentiation of chicken embryonic stem cells infected with subgroup J avian leukosis virus.

Exosome-mediated horizontal and vertical transmission of subgroup J avian leukosis virus (ALV-J) in poultry flocks can lead to growth inhibition and severe immunosuppression. However, there are few reports on the early infection of chicken embryonic stem cells (cESCs) with ALV-J. In this study, we confirmed that early infection with ALV-J can accelerate the differentiation of cESCs and promote the secretion of exosomes. To investigate the modulation strategy of ALV-J in cESCs, circRNA sequencing was performed for further analysis. A total of 305 differentially expressed circRNAs (DECs) were obtained, including 71 upregulated DECs. Circ-CCDC7 was found to be the most upregulated DEC and was assessed by qRT-PCR, with the result consistent with the result of circRNA-seq. Based on qRT-PCR, gga-miR-6568-3p was found to be the target of the top 3 DECs, including circ-CCDC7, and the stem cell marker gene Pax7 was identified as the target gene of gga-miR-6568-3p. This study demonstrated that exosomal circ-CCDC7/gga-miR-6568-3p/Pax7 accelerates the differentiation of cESCs after early infection with ALV-J.

Synthesis of fluorescent gold nanodot-liposome hybrids for detection of phospholipase C and its inhibitor.

We report the synthesis of fluorescent 11-mercaptoundecanoic acid-gold nanodot-liposome (11-MUA-Au ND/Lip) hybrids by incorporation of gold nanoparticles (∼3 nm) and 11-MUA molecules in hydrophobic phospholipid membranes that self-assemble to form small unilamellar vesicles. A simple and homogeneous fluorescence assay for phospholipase C (PLC) was developed on the basis of the fluorescence quenching of 11-MUA-Au ND/Lip hybrids in aqueous solution. The fluorescence of the 11-MUA-Au ND/Lip hybrids is quenched by oxygen (O2) molecules in solution, and quenching is reduced in the presence of PLC. PLC catalyzes the hydrolysis of phosphatidylcholine units from Lip to yield diacylglycerol (DAG) and phosphocholine (PC) products, leading to the decomposition of Lip. The diacylglycerol further interacts with 11-MUA-Au NDs via hydrophobic interactions, leading to inhibition of O2 quenching. The 11-MUA-Au ND/Lip probe provides a limit of detection (at a signal-to-noise ratio of 3) of 0.21 nM for PLC, with high selectivity over other proteins, enzymes, and phospholipases. We have validated the practicality of using this probe for the determination of PLC concentrations in breast cancer cells (MCF-7 and MDA-MB-231 cell lines) and nontumor cells (MCF-10A cell line), revealing that the PLC activity in the first two is at least 1.5-fold higher than that in the third. An inhibitor assay using 11-MUA-Au ND/Lip hybrids demonstrated that tricyclodecan-9-yl potassium xanthate (D609) inhibits PLC (10 nM) with an IC50 value of 3.81 ± 0.22 µM. This simple, sensitive, and selective approach holds great potential for detection of PLC in cancer cells and for the screening of anti-PLC drugs.

Detection of adenosine triphosphate through polymerization-induced aggregation of actin-conjugated gold/silver nanorods.

We have developed a simple and selective nanosensor for the optical detection of adenosine triphosphate (ATP) using globular actin-conjugated gold/silver nanorods (G-actin-Au/Ag NRs). By simply mixing G-actin and Au/Ag NRs (length ~56 nm and diameter ~12 nm), G-actin-Au/Ag NRs were prepared which were stable in physiological solutions (25 mM Tris-HCl, 150 mM NaCl, 5.0 mM KCl, 3.0 mM MgCl2 and 1.0 mM CaCl2; pH 7.4). Introduction of ATP into the G-actin-Au/Ag NR solutions in the presence of excess G-actin induced the formation of filamentous actin-conjugated Au/Ag NR aggregates through ATP-induced polymerization of G-actin. When compared to G-actin-modified spherical Au nanoparticles having a size of 13 nm or 56 nm, G-actin-Au/Ag NRs provided better sensitivity for ATP, mainly because the longitudinal surface plasmon absorbance of the Au/Ag NR has a more sensitive response to aggregation. This G-actin-Au/Ag NR probe provided high sensitivity (limit of detection 25 nM) for ATP with remarkable selectivity (>10-fold) over other adenine nucleotides (adenosine, adenosine monophosphate and adenosine diphosphate) and nucleoside triphosphates (guanosine triphosphate, cytidine triphosphate and uridine triphosphate). It also allowed the determination of ATP concentrations in plasma samples without conducting tedious sample pretreatments; the only necessary step was simple dilution. Our experimental results are in good agreement with those obtained from a commercial luciferin-luciferase bioluminescence assay. Our simple, sensitive and selective approach appears to have a practical potential for the clinical diagnosis of diseases (e.g. cystic fibrosis) associated with changes in ATP concentrations.