Predictive value of triple negative breast cancer based on DCE-MRI multi-phase full-volume ROI clinical radiomics model.

BACKGROUND: Since no studies compared the value of radiomics features of distinct phases of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for predicting triple-negative breast cancer (TNBC). PURPOSE: To identify the optimal phase of DCE-MRI for diagnosing TNBC and, in combination with clinical factors, to develop a clinical-radiomics model to well predict TNBC. MATERIAL AND METHODS: This retrospective study included 158 patients with pathology-confirmed breast cancer, including 38 cases of TNBC. The patients were randomly divided into the training and validation set (7:3). Eight radiomics models were built based on eight DCE-MR phases, and their performances were evaluated using receiver operating characteristic curve (ROC) and DeLong's test. The Radscore derived from the best radiomics model was integrated with independent clinical risk factors to construct a clinical-radiomics predictive model, and evaluate its performance using ROC analysis, calibration, and decision curve analyses. RESULTS: WHO classification, margin, and T2-weighted (T2W) imaging signals were significantly correlated with TNBC and independent risk factors for TNBC (P<0.05). The clinical model yielded areas under the curve (AUCs) of 0.867 and 0.843 in the training and validation sets, respectively. The radiomics model based on DCEphase7 achieved the highest efficacy, with an AUC of 0.818 and 0.777. The AUC of the clinical-radiomics model was 0.936 and 0.886 in the training and validation sets, respectively. The decision curve showed the clinical utility of the clinical-radiomics model. CONCLUSION: The radiomics features of DCE-MRI had the potential to predict TNBC and could improve the performance of clinical risk factors for preoperative personalized prediction of TNBC.

Angiotensin-receptor blocker losartan alleviates atrial fibrillation in rats by downregulating frizzled 8 and inhibiting the activation of WNT-5A pathway.

Atrial fibrillation (AF) is a common arrhythmia. Angiotensin-receptor blocker (ARB) is related to AF treatment. This study explored the mechanism of ARB in AF. AF rat models were established by Ach-CaCl2 mixed solution injection. Rats were treated with ARB by gavage and injected with pcDNA3.1-based frizzled homolog 8 (FZD8) overexpression plasmids (oe-FZD8) through the tail vein. The 12-lead electrocardiogram was recorded by biological signal acquisition and processing system and AF duration was recorded, and atrial effective refractory period (AERP) was monitored by electrophysiology. Atrial fibrosis degree, FZD8 messenger RNA and protein levels, collagen I, collagen III, transforming growth factor ß1 (TGF-ß1), fibronectin, α smooth muscle actin (α-SMA), WBT-5B, and p-JNK1/2 levels, interleukin 1 ß (IL-1ß) and interleukin 6 (IL-6) levels were detected by Masson staining, reverse transcription quantitative polymerase chain reaction, western blot assay, immunohistochemistry, and enzyme-linked immunosorbent assay. ACh-CaCl2-induced AF rats showed a large area of fused necrosis, abnormal collagen fibre proliferation, high atrial fibrosis degree, and increased atrial fibrosis area in atrial interstitium, elevated collagen I, collagen III, TGF-ß1, fibronectin, α-SMA, IL-1ß, and IL-6 levels, whereas these trends were averted by ARB treatment. FZD8 was highly expressed in AF rat myocardium. ARB repressed FZD8 expression, prolonged AERP and reduced AF incidence. FZD8 overexpression annulled the effects of ARB on improving AF rat myocardial fibrosis. ARB inactivated the WNT-5A pathway by suppressing FZD8. ARB inactivated the WNT-5A pathway by silencing FZD8, therefore, alleviating AF rat atrial fibrosis.

Iron availability is a key factor for freshwater cyanobacterial survival against saline stress.

Estuaries are among the most productive ecosystems and dynamic environments on Earth. Varying salinity is the most important challenge for phytoplankton survival in estuaries. In order to investigate the role of iron nutrition on phytoplankton survival under salinity stress, a freshwater cyanobacterial strain was cultivated in media added with different proportions of seawater (measured with siderophore activities), and supplied with gel-immobilized ferrihydrite as iron source. Results showed that the strain grew well in media with 0% seawater supplied with ferrihydrite as iron source. Surprisingly, the biomasses in media with 50% seawater, with more newly excreted siderophore, were similar to those with 0% seawater, but better than those with 6.25%, 12.5% and 25% seawater. Smaller iron isotopic discriminations between the cyanobacterial cells associated iron and dissolved iron were observed in media with 0% and 50% seawater suggested that higher fractions of iron uptake from aqueous dissolved iron reservoir by these comparatively larger biomasses. In summary, this study proved that iron availability plays a key role in cyanobacterial survival under varying salinity stress, and suggested that siderophores introduced by seawater may accelerate iron dissolution, increase iron availability, and make cyanobacterial cells overcome the adverse effects of high-salinity, and indicated that siderophore excretion is a kind of survival strategy for phytoplankton in face of salinity stress.

Mutations of Helicobacter pylori RdxA are mainly related to the phylogenetic origin of the strain and not to metronidazole resistance.

OBJECTIVES: Drug resistance of Helicobacter pylori is a major clinical problem worldwide. The objective of the present study was to investigate the prevalence of antibiotic-resistant H. pylori in the city of Shenzhen in China, as well as to identify the genetic mutations specifically associated with drug resistance rather than unrelated phylogenetic signals. METHODS: Antibiotic susceptibility testing was performed on 238 clinical strains successfully isolated from H. pylori-positive dyspeptic patients who underwent gastroscopy at the Department of Gastroenterology in Shenzhen People's Second Hospital. Following WGS of all strains using Illumina technology, mutation and phylogenetic analyses were performed. RESULTS: The resistance rates were 84.9%, 35.3%, 25.2% and 2.1% for metronidazole, clarithromycin, ciprofloxacin and rifampicin, respectively. An A2143G conversion in the 23S rRNA gene was the primary mutation observed in clarithromycin-resistant strains, whilst N87K/I and D91G/N/Y in GyrA were detected in ciprofloxacin-resistant strains. In RdxA, our results demonstrated that only R16H/C and M21A are significant contributors to metronidazole resistance; there were 15 other sites, but these are phylogenetically related and thus unrelated to metronidazole resistance. CONCLUSIONS: There is a high prevalence of metronidazole, clarithromycin and ciprofloxacin resistance and a low prevalence of rifampicin resistance in H. pylori from Shenzhen, China. Omission of phylogenetically related sites will help to improve identification of sites genuinely related to antibiotic resistance in H. pylori and, we believe, other species.

High-precision magnesium isotope analysis of geological and environmental reference materials by multiple-collector inductively coupled plasma mass spectrometry.

RATIONALE: High-precision magnesium (Mg) isotopic analysis for geological and environmental reference materials is a prerequisite to ensure data quality before using Mg isotopes to trace geochemical and environmental processes. However, the Mg-isotopic ratios of many commonly used reference materials, especially sediments, have rarely been reported. Furthermore, published values for some commonly used reference materials exhibit a significant inconsistency across laboratories and thus need more data comparison. METHODS: We developed different Mg purification schemes for silicate rocks, high-Ca carbonates and carbonatites, and high-Mn samples because of their significantly different matrices. We then used synthetic solutions to evaluate potential effects on measurement using multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The accuracy and precision of our procedures were assessed by measurement on both synthetic solutions and well-studied geostandards. RESULTS: The three different schemes for routine, high-Ca, and high-Mn samples can remove matrices efficiently with nearly 100% Mg yield. However, the presence of acid molarity and concentration mismatch, matrix elements, and fluctuations in room temperature can significantly affect the precision and accuracy of Mg isotope analysis, and must be avoided. The Mg isotopic ratios of reference materials obtained in this study are identical to the previously published values within ±0.06‰, verifying that our procedures are robust. CONCLUSIONS: This study presented a thorough set of tests for high precision and accuracy of Mg isotope measurements using MC-ICP-MS, which demonstrate reproducibility and accuracy better than 0.05‰ for δ25 Mg values and 0.06‰ for δ26 Mg values. We reported high-quality Mg isotopic data for 16 geological and environmental reference materials to aid the inter-laboratory calibration of Mg isotope measurements in the future.

BDNF promotes human neural stem cell growth via GSK-3ß-mediated crosstalk with the wnt/ß-catenin signaling pathway.

Brain-derived neurotrophic factor (BDNF) plays important roles in neural stem cell (NSC) growth. In this study, we investigated whether BDNF exerts its neurotrophic effects through the Wnt/ß-catenin signaling pathway in human embryonic spinal cord NSCs (hESC-NSCs) in vitro. We found an increase in hESC-NSC growth by BDNF overexpression. Furthermore, expression of Wnt1, Frizzled1 and Dsh was upregulated, whereas GSK-3ß expression was downregulated. In contrast, hESC-NSC growth was decreased by BDNF RNA interference. BDNF, Wnt1 and ß-catenin components were all downregulated, whereas GSK-3ß was upregulated. Next, we treated hESC-NSCs with 6-bromoindirubin-3'-oxime (BIO), a small molecule inhibitor of GSK-3ß. BIO reduced the effects of BDNF upregulation/downregulation on the cell number, soma size and differentiation, and suppressed the effect of BDNF modulation on the Wnt signaling pathway. Our findings suggest that BDNF promotes hESC-NSC growth in vitro through crosstalk with the Wnt/ß-catenin signaling pathway, and that this interaction may be mediated by GSK-3ß.

Preparation, Physicochemical Properties, and Transfection Activities of Tartaric Acid-Based Cationic Lipids as Effective Nonviral Gene Delivery Vectors.

In this work two novel cationic lipids using natural tartaric acid as linking backbone were synthesized. These cationic lipids were simply constructed by tartaric acid backbone using head group 6-aminocaproic acid and saturated hydrocarbon chains dodecanol (T-C12-AH) or hexadecanol (T-C16-AH). The physicochemical properties, gel electrophoresis, transfection activities, and cytotoxicity of cationic liposomes were tested. The optimum formulation for T-C12-AH and T-C16-AH was at cationic lipid/dioleoylphosphatidylethanolamine (DOPE) molar ratio of 1 : 0.5 and 1 : 2, respectively, and N/P charge molar ratio of 1 : 1 and 1 : 1, respectively. Under optimized conditions, T-C12-AH and T-C16-AH showed effective gene transfection capabilities, superior or comparable to that of commercially available transfecting reagent 3ß-[N-(N',N'-dimethylaminoethyl)carbamoyl]cholesterol (DC-Chol) and N-[2,3-dioleoyloxypropyl]-N,N,N-trimethylammonium chloride (DOTAP). The results demonstrated that the two novel tartaric acid-based cationic lipids exhibited low toxicity and efficient transfection performance, offering an excellent prospect as nonviral vectors for gene delivery.

Codon modification for the DNA sequence of a single-chain Fv antibody against clenbuterol and expression in Pichia pastoris.

The expression efficiency was improved for the recombinant single-chain variable fragment (scFv) against clenbuterol (CBL) obtained from mouse and expressed in the methylotrophic yeast Pichia pastoris GS115, by redesigning and synthesizing the DNA sequence encoding for CBL-scFv based on the codon bias of P. pastoris. The codons encoding 124 amino acids were optimized, in which a total of 156 nucleotides were changed, and the G+C ratio was simultaneously decreased from 53 to 47.2 %. Under the optimized expression conditions, the yield of the recombinant CBL-scFv (41 kDa) antibodies was 0.223 g L⁻¹ in shake culture. Compared to the non-optimized control, the expression level of the optimized recombinant CBL-scFv based on preferred codons in P. pastoris demonstrated a 2.35-fold higher yield. Furthermore, the recombinant CBL-scFv was purified by Ni-NTA column chromatography, and the purity was 95 %. The purified CBL-scFv showed good CBL recognition by a competitive indirect enzyme-linked immunoassay. The average concentration required for 50 % inhibition of binding and the limit of detection for the assay were 5.82 and 0.77 ng mL⁻¹, respectively.

Integrative radiomics clustering analysis to decipher breast cancer heterogeneity and prognostic indicators through multiparametric MRI.

Breast cancer diagnosis and treatment have been revolutionized by multiparametric Magnetic Resonance Imaging (mpMRI), encompassing T2-weighted imaging (T2WI), Diffusion-weighted imaging (DWI), and Dynamic Contrast-Enhanced MRI (DCE-MRI). We conducted a retrospective analysis of mpMRI data from 194 breast cancer patients (September 2019 to October 2023). Using 'pyradiomics' for radiomics feature extraction and MOVICS for unsupervised clustering. Interestingly, we identified two distinct patient clusters associated with significant differences in molecular subtypes, particularly in Luminal A subtype distribution (p = 0.03), estrogen receptor (ER) (p = 0.01), progesterone receptor (PR) (p = 0.04), mean tumor size (p < 0.01), lymph node metastasis (LNM) (p = 0.01), and edema (p < 0.01). Our study emphasizes mpMRI's potential in breast cancer by using radiomics-based cluster analysis to categorize tumors, uncovering heterogeneity, and aiding in personalized treatment strategies.

Seismic response of mountain tunnel induced by fault slip.

With the rapid development of Chinese transportation networks, such as the Sichuan-Tibet railway, numerous tunnels are under construction or planned in mountainous regions. Some of these tunnels must traverse or be situated near active fault zones, which could suffer damage from fault slip. In this study, the seismic response of a mountain tunnel subjected to coseismic faulting was analyzed using a fault-structure system in a two-step process. Firstly, a nonuniform slip model was proposed to calculate the ground deformations and internal displacements induced by a specific active fault on a geological scale, considering nonuniform slips on the fault plane. The 1989 Loma Prieta and 2022 Menyuan earthquakes were chosen as case studies to validate the proposed slip model. Secondly, the calculated displacement of the Menyuan earthquake was used as the input load for the discrete-continuous coupling analysis of the Daliang tunnel on an engineering scale. The simulated deformation of the Daliang tunnel aligned with the on-site damage observations following the Menyuan earthquake. Lastly, the effects of different fault conditions on the tunnel seismic response were investigated. The results indicate that the distribution of the peak longitudinal strain of the lining is governed by fault mechanisms, and the degree of fault slip significantly influences the response of the tunnel. A tunnel passing through an active fault with a wider fault fracture zone and smaller dip angle experience less damage.

Magnetic resonance image restoration via least absolute deviations measure with isotropic total variation constraint.

This paper presents a magnetic resonance image deblurring and denoising model named the isotropic total variation regularized least absolute deviations measure (LADTV). More specifically, the least absolute deviations term is first adopted to measure the violation of the relation between the desired magnetic resonance image and the observed image, and to simultaneously suppress the noise that may corrupt the desired image. Then, in order to preserve the smoothness of the desired image, we introduce an isotropic total variation constraint, yielding the proposed restoration model LADTV. Finally, an alternating optimization algorithm is developed to solve the associated minimization problem. Comparative experiments on clinical data demonstrate the effectiveness of our approach to synchronously deblur and denoise magnetic resonance image.

1,7-diphenyl-4-hepten-3-one mitigates Alzheimer's-like pathology by inhibiting pyroptosis via activating the Nrf2 pathway.

Pyroptosis-mediated neuron death plays a crucial role in neurodegenerative diseases, such as Alzheimer's disease (AD). However, the effect of 1,7-diphenyl-4-hepten-3-one (C1), a natural diarylheptanoid, on AD is unclear. Herein, we investigated the therapeutic effect of C1 on APP/PS1 mice and ß-amyloid (Aß)-induced HT22 cells. Our findings showed that C1 attenuated cognitive impairment and mitigated pathological damage in APP/PS1 mice. Furthermore, we found that C1 prevented oxidative stress damage and decreased the levels of pyroptosis-related proteins. In vitro experiments showed that C1 can improve the proliferation of Aß-induced HT22 cells and decrease the levels of pyroptosis-related proteins in them. When Nrf2 was silenced, the positive effects of C1 in inhibiting pyroptosis were inhibited. Particularly, the production of pyroptosis-associated proteins, including NLRP3, GSDMD, and caspase-1, and the secretion of pro-inflammatory molecules, including IL-1 and IL-18, were increased. Altogether, these findings indicate that C1 can mitigate AD-like pathology via the inhibition of pyroptosis by activating the Nrf2 pathway. We believe that this study can provide alternative strategies for the prevention and treatment of AD.

The clinical value of dual-energy CT imaging in preoperative evaluation of pathological types of gastric cancer.

BACKGROUND: Gastric cancer (GC) is the fifth most common cancer worldwide and the third leading cause of cancer death. Due to the low rate of early diagnosis, most patients are already in the advanced stage and lose the chance of radical surgery. OBJECTIVE: To investigate the clinical value of computed tomography (CT) dual-energy imaging in preoperative evaluation of pathological types of gastric cancer patients. METHODS: 121 patients with gastric cancer were selected. Dual-energy CT imaging was performed on the patients. The CT values of virtual noncontrast (VNC) images and iodine concentration of the lesion were measured, and the standardized iodine concentration ratio was calculated. The iodine concentration, iodine concentration ratio and CT values of VNC images of different pathological types were analyzed and compared. RESULTS: The iodine concentration and iodine concentration ratio of gastric mucinous carcinoma patients in venous phase and parenchymal phase were lower than those of gastric non-mucinous carcinoma patients, and the differences were statistically significant (P< 0.05). The iodine concentration and iodine concentration ratio of patients with mucinous adenocarcinoma in venous phase and parenchymal phase were lower than those of patients with choriocarcinoma, and the differences were statistically significant (P< 0.05). The iodine concentration and iodine concentration ratio of middle and high differentiated adenocarcinoma patients in venous phase and parenchymal phase were lower than those of low differentiated adenocarcinoma patients, and the differences were statistically significant (P< 0.05). However, there was no significant difference in CT values of VNC images among venous, arterial, and parenchymal phases in all pathological types of gastric cancer patients (P> 0.05). CONCLUSION: Dual-energy CT imaging plays an important role in the preoperative evaluation of patients with gastric cancer. The pathological types of gastric cancer are different, and the iodine concentration will change accordingly. Dual-energy CT imaging can effectively evaluate the pathological types of gastric cancer and has high clinical application value.

Observation and research of deep underground multi-physical fields-Huainan -848 m deep experiment.

Compared with the surface, the deep environment has the advantages of allowing "super-quiet and ultra-clean"-geophysical field observation with low vibration noise and little electromagnetic interference, which are conducive to therealization of long-term and high-precision observation of multi-physical fields, thus enabling the solution of a series of geoscience problems. In the Panyidong Coal Mine, where there are extensive underground tunnels at the depth of 848 m belowsea level, we carried out the first deep-underground geophysical observations, including radioactivity, gravity, magnetic, magne-totelluric, background vibration and six-component seismic observations. We concluded from these measurements that (1) the background of deep subsurface gravity noise in the long-period frequency band less than 2 Hz is nearly two orders ofmagnitude weaker than that in the surface observation environment; (2) the underground electric field is obviously weaker thanthe surface electric field, and the relatively high frequency of the underground field, greater than 1 Hz, is more than two orders of magnitude weaker than that of the surface electric field; the east-west magnetic field underground is approximately the same asthat at the surface; the relatively high-frequency north-south magnetic field underground, below 10 Hz, is at least one order ofmagnitude lower than that at the surface, showing that the underground has a clean electromagnetic environment; (3) in additionto the high-frequency and single-frequency noises introduced by underground human activities, the deep underground spacehas a sig-nificantly lower background vibration noise than the surface, which is very beneficial to the detection of weakearthquake and gravity signals; and (4) the underground roadway support system built with ferromagnetic material interferesthe geomagnetic field. We also found that for deep observation in the "ultra-quiet and ultra-clean" environment, the existinggeophysical equipment and observation technology have problems of poor adaptability and insufficient precision as well asdata cleaning problems, such as the effective separation of the signal and noise of deep observation data. It is also urgent tointerpret and comprehensively utilize these high-precision multi-physics observation data. Electronic Supplementary Material: Supplementary material is available in the online version of this article at 10.1007/s11430-022-9998-2.

LncRNA MINCR attenuates osteoarthritis progression via sponging miR-146a-5p to promote BMPR2 expression.

The purposes of this study are to explore the function and regulatory mechanism of a novel lncRNA MYC-Induced Long non-coding RNA (MINCR) in osteoarthritis (OA). The expression of lncRNA MINCR, miR-146a-5p, and bone morphogenetic protein receptor 2 (BMPR2), Sry-type high-mobility-group box 9 (SOX9), collagen type II alpha 1 (COL2A1), Aggrecan, metalloproteinase with thrombospondin motifs-4 (ADAMTS-4), Matrix metalloproteinase 3 (MMP3), MMP13, COL2A1, and Aggrecan were determined using quantitative real-time PCR (qRT-PCR), western blot, immunohistochemistry (IHC) and immunofluorescence (IF) in vitro and in vivo. And distribution and expression of MINCR were examined by fluorescence in situ hybridization (FISH). Cell proliferation and apoptosis were detected by cell counting kit-8 (CCK-8) assay, 5-Ethynyl-2'-deoxyuridine (EdU) staining, Annexin V-FITC/Propidium Iodide (PI), and Terminal Deoxynucleotidyl transferase-mediated dUTP Nick-End Labeling (TUNEL) staining in vitro and in vivo. The anterior cruciate ligament transection (ACLT) rat model was constructed to analyze the MINCR/miR-146a-5p/BMPR2 axis in vivo. The cartilage degeneration was determined by pathological staining with Hematoxylin and Eosin (H&E) and Safranin O staining. The binding relationship between MINCR and miR-146a-5p, and between miR-146a-5p and BMPR2 were determined by a dual-luciferase reporter gene, RNA Immunoprecipitation (RIP) assay, and RNA-pull down assays. Here, MINCR and BMPR2 were downregulated whereas miR-146a-5p was upregulated in OA cartilage tissues compared with control as well as IL-1ß-induced chondrocytes compared with normal chondrocytes. Function experiments indicated that MINCR upregulation promoted cell proliferation and inhibited apoptosis and extracellular matrix (ECM)-degeneration. We also proved the binding relationship between MINCR and miR-146a-5p, and the BMPR2 acted as a target of miR-146a-5p. Mechanism analysis using rescue experiments in vitro and in vivo, MINCR silencing reversed the effects of miR-146a-5p downregulation in OA. Overexpression of miR-146a-5p also reversed the function of BMPR2 overexpression in OA. These data indicated that MINCR prevented OA progression via targeting miR-146a-5p to promote BMPR2 expression.

Identification of core genes as potential biomarkers for predicting progression and prognosis in glioblastoma.

Background: Glioblastoma is a common malignant neuroepithelial neoplasm with poor clinical outcomes and limited treatment options. It is extremely important to search and confirm diverse hub genes that are effective in the advance and prediction of glioblastoma. Methods: We analyzed GSE50161, GSE4290, and GSE68848, the three microarray datasets retrieved from the GEO database. GO function and KEGG pathway enrichment analyses for differentially expressed genes (DEGs) were performed using DAVID. The PPI network of the DEGs was analyzed using the Search Tool for the Retrieval of Interacting Genes database and visualized by Cytoscape software. Hub genes were identified through the PPI network and a robust rank aggregation method. The Cancer Genome Atlas (TCGA) and the Oncomine database were used to validate the hub genes. In addition, a survival curve analysis was conducted to verify the correlation between the expression of hub genes and patient prognosis. Human glioblastoma cells and normal cells were collected, and then RT-PCR, Western blot, and immunofluorescence were conducted to validate the expression of the NDC80 gene. A cell proliferation assay was used to detect the proliferation of glioma cells. The effects of NDC80 expression on migration and invasion of GBM cell lines were evaluated by conducting scratch and transwell assays. Results: A total of 716 DEGs were common to all three microarray datasets, which included 188 upregulated DEGs and 528 downregulated DEGs. Furthermore, we found that among the common DEGs, 10 hub genes showed a high degree of connectivity. The expression of the 10 hub genes in TCGA and the Oncomine database was significantly overexpressed in glioblastoma compared with normal genes. Additionally, the survival analysis showed that the patients with low expression of six genes (BIR5C, CDC20, NDC80, CDK1, TOP2A, and MELK) had a significantly favorable prognosis (p < 0.01). We discovered that NDC80, which has been shown to be important in other cancers, also has an important role in malignant gliomas. The RT-PCR, Western blot, and immunofluorescence results showed that the expression level of NDC80 was significantly higher in human glioblastoma cells than in normal cells. Moreover, we identified that NDC80 increased the proliferation and invasion abilities of human glioblastoma cells. Conclusion: The six genes identified here may be utilized to form a panel of disease progression and predictive biomarkers of glioblastoma for clinical purposes. NDC80, one of the six genes, was discovered to have a potentially important role in GBM, a finding that needs to be further studied.

Functional analysis of a rice late pollen-abundant UDP-glucose pyrophosphorylase (OsUgp2) promoter.

OsUgp2, a rice UDP-glucose pyrophosphorylase gene, has previously been shown to preferentially express in maturing pollens and plays an important role in pollen starch accumulation. Here, a 1943 bp promoter fragment (P1943) of OsUgp2 was characterized by 5' deletion and gain-of-function experiments. P1943 and its 5' deletion derivatives (P1495, P1005, P665 and P159) were fused to GUS reporter gene and stably introduced into rice plants. Histochemical analyses of different tissues and pollens at different developmental stages of the transgenic plants showed that P1943 could only direct GUS expression in binucleate pollens. P1495 and P1005 could still drive GUS expression in binucleate pollens but at a lower level. On the other hand, neither P665 nor P159 transformant exhibited any GUS activity in pollens. Gain-of-function analyses showed that the region (-1005 to -665 relative to translation start site) combined with a minimal CaMV 35S promoter could direct GUS expression in pollens. Further analysis of 5' deletion truncated at -952, -847 and -740 delimited a 53 bp region (-1005 to -952) essential for pollen-specific expression. The 53 bp sequence contains two motifs of TTTCT and TTTC, which were known to be pollen-specific cis-elements. In addition, the same P1943-GUS fusion construct was introduced into tobacco to analyze its specificity in dicotyledon. Interestingly, the GUS expression pattern in transgenic tobacco was quite different from that in rice. High level of GUS expression was detected in mature pollens as well as leaves, roots, sepals and stigmas. These findings suggested a complicated transcriptional regulation of OsUgp2.

Atomically Dispersed Co2+ Sites Incorporated into a Silicalite-1 Zeolite Framework as a High-Performance and Coking-Resistant Catalyst for Propane Nonoxidative Dehydrogenation to Propylene.

Propane nonoxidative dehydrogenation (PDH) is a promising route to produce propylene with the development of shale gas exploration technology. Co-based catalysts with low cost and low toxicity could activate C-H effectively, but they suffer from deactivation with coke formation. In this work, a catalyst formed by incorporating highly dispersed Co sites into a Silicalite-1 zeolite framework (Co-Silicalite-1) is synthesized by a hydrothermal protocol in the presence of ammonia, which exhibits superior propane dehydrogenation catalytic performance with 0.0946 mmol C3H6·s-1·gCo-1 and propylene selectivity higher than 98.5%. It also shows outstanding catalytic stability and coking resistance in a 3560 min time-on-stream. Combined characterization results demonstrate that the tetrahedrally coordinated Co2+ site serves as the PDH catalytic active site, which is stabilized by Si-O units of the zeolite framework. Incorporation of Co sites into the zeolite framework could avoid the reduction of Co species to metallic Co. Moreover, the catalytic performance is improved by the enhanced propane adsorption and propylene desorption.

A re-testing range is recommended for 13C- and 14C-urea breath tests for Helicobacter pylori infection in China.

BACKGROUND: The urea breath test (UBT) is widely used for diagnosing Helicobacter pylori infection. In the Shenzhen Kuichong People's Hospital, some UBT findings were contradictory to the histology outcomes, therefore this study aimed to assess and compare the diagnostic performance of both 13C- and 14C-UBT assays. METHODS: We recruited 484 H. pylori-treatment naïve patients, among which 217 and 267 were tested by the 13C-UBT or 14C-UBT, respectively. The cutoff value for H. pylori positivity based on manufacturer's instruction was 4% delta over baseline (DOB) for the 13C-UBT, and 100 disintegrations per minute (DPM) for the 14C-UBT. Gastric biopsies of the antrum and corpus were obtained during endoscopy for histopathology. RESULTS: In patients who were tested using the 13C-UBT kit, histopathology was positive in 136 out of 164 UBT-positive patients (82.9% concordance), and negative in 46 out of 53 UBT-negative cases (86.8% concordance). For the 14C-UBT-tested patients, histopathology was positive for H. pylori in 186 out of 220 UBT-positive patients (84.5% concordance), and negative in 41 out of 47 UBT-negative cases (87.2% concordance). While the 13C-UBT and 14C-UBT each had a high sensitivity level of 95.1% and 96.9%, respectively, their specificity was low, at 62.2% and 54.7%, respectively. By using new optimal cutoff values and including an indeterminate range (3-10.3% DOB for 13C-UBT and 87-237 DPM for 14C-UBT), the specificity values can be improved to 76.7% and 76.9% for the 13C- and 14C-UBT, respectively. CONCLUSIONS: The establishment of an indeterminate range is recommended to allow for repeated testing to confirm H. pylori infection, and thereby avoiding unnecessary antibiotic treatment. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2000041570. Registered 29 December 2020- Retrospectively registered, http://www.chictr.org.cn/edit.aspx?pid=66416&htm=4.

Expression and purification of an anti-clenbuterol single chain Fv antibody in Escherichia coli.

Recombinant antibodies with desirable characteristics that can replace polyclonal or monoclonal antibodies are important for enzyme-linked immunosorbent assay (ELISA) of residues of clenbuterol (CBL), an illicit veterinary drug. Here, we report our work on expression and purification of a mouse-derived anti-CBL single chain Fv (scFv) antibody in Escherichia coli (E. coli). An expression plasmid pBV220-CBL was constructed and transformed into E. coli BL21 (DH3) strain cells. After induction by temperature, the 6x His-tagged anti-CBL scFv antibodies were expressed with the yield of 31%. The solubilized inclusion bodies were extracted, denatured and then purified by Ni-NTA column chromatography. The purified recombinant target protein was analyzed by high performance liquid chromatography, SDS-PAGE and Western blotting, respectively. The results showed the prepared anti-CBL scFv antibodies posed HRP-anti-His-tag antibody-recognized activity and their purity was up to 96%. Moreover, an indirect competitive ELISA based on the anti-CBL scFv antibodies revealed that the limit of detection for CBL was 0.5 ng/ml and the linear range was 1.5-10.6 ng/ml. Taken together, these findings suggest that the prepared recombinant antibody can be used for future immunoassay detection for CBL.