Convolutional neural network assistance significantly improves dermatologists' diagnosis of cutaneous tumours using clinical images.

BACKGROUND: Convolutional neural networks (CNNs) have demonstrated expert-level performance in cutaneous tumour classification using clinical images, but most previous studies have focused on dermatologist-versus-CNN comparisons rather than their combination. The objective of our study was to evaluate the potential impact of CNN assistance on dermatologists for clinical image interpretation. METHODS: A multi-class CNN was trained and validated using a dataset of 25,773 clinical images comprising 10 categories of cutaneous tumours. The CNN's performance was tested on an independent dataset of 2107 images. A total of 400 images (40 per category) were randomly selected from the test dataset. A fully crossed, self-control, multi-reader multi-case (MRMC) study was conducted to compare the performance of 18 board-certified dermatologists (experience: 13/18 ≤ 10 years; 5/18＞10 years) in interpreting the 400 clinical images with or without CNN assistance. RESULTS: The CNN achieved an overall accuracy of 78.45% and kappa of 0.73 in the classification of 10 types of cutaneous tumours on 2107 images. CNN-assisted dermatologists achieved a higher accuracy (76.60% vs. 62.78%, P < 0.001) and kappa (0.74 vs. 0.59, P < 0.001) than unassisted dermatologists in interpreting the 400 clinical images. Dermatologists with less experience benefited more from CNN assistance. At the binary classification level (malignant or benign), the sensitivity (89.56% vs. 83.21%, P < 0.001) and specificity (87.90% vs. 80.92%, P < 0.001) of dermatologists with CNN assistance were also significantly improved than those without. CONCLUSIONS: CNN assistance improved dermatologist accuracy in interpreting cutaneous tumours and could further boost the acceptance of this new technique.

Glutamine Imaging: A New Avenue for Glioma Management.

The glutamine pathway is emerging as an important marker of cancer prognosis and a target for new treatments. In gliomas, the most common type of brain tumors, metabolic reprogramming leads to abnormal consumption of glutamine as an energy source, and increased glutamine concentrations are associated with treatment resistance and proliferation. A key challenge in the development of glutamine-based biomarkers and therapies is the limited number of in vivo tools to noninvasively assess local glutamine metabolism and monitor its changes. In this review, we describe the importance of glutamine metabolism in gliomas and review the current landscape of translational and emerging imaging techniques to measure glutamine in the brain. These techniques include MRS, PET, SPECT, and preclinical methods such as fluorescence and mass spectrometry imaging. Finally, we discuss the roadblocks that must be overcome before incorporating glutamine into a personalized approach for glioma management.

[Analysis of screening results and risk factors of high-risk populations of lung cancer in Nanchang city from 2018 to 2019].

Objective: To collate and analyze the screening results of high-risk lung cancer populations in communities in Nanchang from 2018 to 2019, and to explore the lung-positive nodules and risk factors for lung cancer. Methods: Data of the screening subjects in 8 administrative districts and 15 street health service centers in Nanchang city, Jiangxi province from November 2018 to October 2019 were collected, people at high risk of lung cancer was assessed, clinical screening of high-risk groups of lung cancer was conducted by low-dose helical computed tomography (LDCT), and risk factors for suspected lung cancer and lung-positive nodules were analyzed. Results: Of the 25 871 people participated in screening, 5 220 were at high risk for lung cancer and 15 374 without other malignant tumors were at high risk. There were 2 417 cases participated in clinical LDCT screening, including 193 cases of lung-positive nodules, 67 cases of suspected lung cancer, 912 cases of other lung diseases, the positive rate of lung cancer or lung-positive nodules was 10.76% (260/2 417). Univariate analysis showed that age, coarse grain intake, oil intake, housing heating, passive smoking, alcohol consumption and mental trauma were associated with positive pulmonary nodules or lung cancer (all P<0.05). Multivariate analysis showed that gender, age, housing heating, smoking and drinking were related to the occurrence of lung nodules or lung cancer (all P<0.05). Conclusions: Men are more likely to develop lung cancer or lung-positive nodules than women. The age is an independent risk factor for lung-positive nodules or lung cancer. In a certain range, age will increase the incidence of lung cancer, housing heating may be the protective factor for lung cancer, while smoking and drinking are risk factors.

LncRNA DGCR5 promotes non-small cell lung cancer progression via sponging miR-218-5p.

Since this article has been suspected of research misconduct and the corresponding authors did not respond to our request to prove originality of data and figures, "LncRNA DGCR5 promotes non-small cell lung cancer progression via sponging miR-218-5p, by J. Wang, H.-Z. Shu, C.-Y. Xu, S.-G. Guo, published in Eur Rev Med Pharmacol Sci 2019; 23 (22): 9947-9954-DOI: 10.26355/eurrev_201911_19561-PMID: 31799664" has been withdrawn. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/19561.

MiR-16 inhibits pituitary adenoma cell proliferation via the suppression of ERK/MAPK signal pathway.

Since this article has been suspected of research misconduct and the corresponding authors did not respond to our request to prove originality of data and figures, "MiR-16 inhibits pituitary adenoma cell proliferation via the suppression of ERK/MAPK signal pathway, by D.-W. Wang, Y.-Q. Wang, H.-S. Shu, published in Eur Rev Med Pharmacol Sci 2018; 22 (5): 1241-1248-DOI: 10.26355/eurrev_201803_14464-PMID: 29565480" has been withdrawn. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/14464.

LncRNA DGCR5 promotes non-small cell lung cancer progression via sponging miR-218-5p.

OBJECTIVE: Non-small cell lung cancer (NSCLC) is one of the most ordinary malignant tumors worldwide. Recent researches have proved that long noncoding RNAs (lncRNAs) play vital roles in many diseases. The aim of this study was to investigate the exact function of lncRNA DiGeorge syndrome critical region gene 5 (DGCR5) in the development of NSCLC. PATIENTS AND METHODS: Real Time-quantitative Polymerase Chain Reaction (RT-qPCR) was utilized to detect DGCR5 expression in paired NSCLC patients' tissue samples and cell lines. The function of DGCR5 in NSCLC was detected through wound healing assay and transwell assay in vitro. Besides, mechanism assays were conducted to observe the interaction between DGCR5 and microRNA-218-5p (miR-218-5p). RESULTS: DGCR5 was remarkably highly expressed in NSCLC tissues compared to that of adjacent normal tissues. The migration and invasion of NSCLC cells were significantly promoted via overexpression of DGCR5. However, the silence of DGCR5 significantly inhibited NSCLC cell migration and invasion. Moreover, RT-qPCR results revealed that miR-218-5p was down-regulated via overexpression of DGCR5, while miR-218-5p was up-regulated after the knockdown of DGCR5. Further experiments showed that miR-218-5p was a direct target of DGCR5 in NSCLC. CONCLUSIONS: DGCR5 enhances NSCLC cell migration and invasion via targeting miR-218-5p, indicating that DGCR5 may be a potential therapeutic target in NSCLC.

Serum immunoinflammation-related protein complexes discriminate between inflammatory bowel disease and colorectal cancer.

PURPOSE: Inflammatory bowel disease (IBD) is an important risk factor for colon cancer. Novel serum immunoinflammation-related protein complexes (IIRPCs) have shown associations with early cancer detection. Herein, we investigated the potential of serum IIRPCs for discriminating between IBD and colorectal cancer (CRC) patients. METHODS: Serum protein complexes of 65 healthy controls, 57 CRC, 69 (ulcerative colitis) UC, and 67 (Crohn's disease) CD patients were isolated by native-PAGE. The gray values of serum IIRPCs bands in the gel were quantified using Quantity One software. The receiver-operating characteristic (ROC) curves were constructed to assess the discriminating ability by calculating the area under the ROC curve. RESULTS: The serum IIRPCs levels in IBD and CRC patients were significantly elevated compared to healthy controls. ROC analysis indicated certain diagnostic ability of serum IIRPCs in differentiating IBD from CRC. Specifically, "a3" complex discriminated UC from CRC, with an AUC value of 0.722, sensitivity of 69.4% and specificity of 63.8%. Similarly, "b4" complex discriminated UC from CRC, with an AUC value of 0.709, sensitivity of 70.4%, and specificity of 60.0%. In addition, the "a3" complex also discriminated CD from CRC, with an AUC value of 0.785, sensitivity of 73.1%, and specificity of 74.1%, while the "b4" complex showed a tendency to discriminate CD from CRC, with an AUC value of 0.663, sensitivity of 67.9% and specificity of 50.0%. Thus, an equation based on multiple IIRPCs was built to further improve the discriminating power. CONCLUSIONS: Serum IIRPCs can be used to discriminate IBD from CRC and may also be associated with early screening of colitis-associated cancer.

Pseudo CT Estimation using Patch-based Joint Dictionary Learning.

Magnetic resonance (MR) simulators have recently gained popularity; it avoids the unnecessary radiation exposure associated with Computed Tomography (CT) when used for radiation therapy planning. We propose a method for pseudo CT estimation from MR images based on joint dictionary learning. Patient-specific anatomical features were extracted from the aligned training images and adopted as signatures for each voxel. The most relevant and informative features were identified to train the joint dictionary learning-based model. The well-trained dictionary was used to predict the pseudo CT of a new patient. This prediction technique was validated with a clinical study of 12 patients with MR and CT images of the brain. The mean absolute error (MAE), peak signal-to-noise ratio (PSNR), normalized cross correlation (NCC) indexes were used to quantify the prediction accuracy. We compared our proposed method with a state-of-the-art dictionary learning method. Overall our proposed method significantly improves the prediction accuracy over the state-of-the-art dictionary learning method. We have investigated a novel joint dictionary Iearning- based approach to predict CT images from routine MRIs and demonstrated its reliability. This CT prediction technique could be a useful tool for MRI-based radiation treatment planning or attenuation correction for quantifying PET images for PET/MR imaging.

Role of spinal cyclooxygenase-2 and prostaglandin E2 in fentanyl-induced hyperalgesia in rats.

BACKGROUND: Accumulated evidence suggests that spinal cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) may be implicated in the development of opioid-induced hyperalgesia. METHODS: Rats received subcutaneous fentanyl injections at different doses (20-80 µg kg-1), four separate times at 15-min intervals. Some rats only received fentanyl (60 µg kg-1 × 4 doses) with or without surgical incision. Fentanyl-induced hyperalgesia was evaluated via a tail-pressure or paw-withdrawal test. The concentrations of spinal COX-2, EP-1 receptor (EP-1R) mRNA, and PGE2 were measured. The effects of the COX-2 inhibitor, parecoxib (intraperitoneal 10 mg kg-1), or the EP-1R antagonist, SC51089 (intraperitoneal 100 µg kg-1), on hyperalgesia and spinal PGE2 were examined. RESULTS: Acute repeated injections of fentanyl dose-dependently induced mechanical hyperalgesia, which reached a peak at the 1st day and persisted for 1-4 days postinjection. This hyperalgesia could be partly or totally prevented by the pretreatment of either parecoxib or SC51089. Consistently, the levels of spinal COX-2 mRNA and PGE2 were also dose-dependently increased, reaching a peak at the first day and persisting for 2 days postinjection. Pretreatment with parecoxib could block the increase in spinal PGE2 and had no effects on spinal COX-2 and EP-1R mRNA. Fentanyl injection enhanced incision-induced mechanical and thermal hyperalgesia. CONCLUSIONS: Acute repeated fentanyl administration dose-dependently produced mechanical hyperalgesia and augmented surgery induced postoperative hyperalgesia. This behavioural change was paralleled with an increase in spinal COX-2 mRNA and PGE2 after fentanyl administration. Inhibition of COX-2 or blockade of EP-1R can partly or totally prevent hyperalgesia.

MiR-16 inhibits pituitary adenoma cell proliferation via the suppression of ERK/MAPK signal pathway.

OBJECTIVE: Extracellular signal-regulated kinase (ERK)/mitogen activated protein kinase (MAPK) signal pathway participates in cell proliferation, cycle, and apoptosis. MiR-16 is down-regulated in the pituitary tumor. This study investigated the role and related mechanism of miR-16 on pituitary tumor proliferation, cycle, and apoptosis. PATIENTS AND METHODS: Dual-luciferase reporter assay was conducted to demonstrate the targeted regulation between miR-16 and MEK1. MiiR-16, MEK1, p-ERK1/2, Survivin and Cyclin D1 expression were compared between normal embryonic pituitary cells, HP75 tumor cells. Flow cytometry detection measured cell proliferation and cycle. Cultured HP75 cells were divided into four groups: miR-NC, miR-16 mimic, si-NC, and si-MEK1. Expressions of miR-16, MEK1, p-ERK1/2, Survivin, and Cyclin D1 were compared, and cell proliferation, cycle, and apoptosis were tested by flow cytometry. RESULTS: Bioinformatics analysis showed complementary binding sites between miR-16 and MEK1. Dual luciferase reporter assay validated the direct regulation between miR-16 and MEK1. Compared to that of normal pituitary tissues, significantly lower miR-16 expression, but higher MEK1 level were found in adenoma tissues. Compared to normal embryonic pituitary cells, the level of miR-16 was decreased, while the expressions of p-ERK1/2, Survivin, and Cyclin D1, along with cell proliferation or S or G2/M phase ratio were up-regulated in the group of HP75 cells. Transfection of miR-16 mimic or si-MEK1 remarkably suppressed the expressions of MEK1, p-ERK1/2, Survivin or Cyclin D1 in HP75 cells, inhibited cell proliferation and induced apoptosis and cycle arrest. CONCLUSIONS: MiR-16 inhibited ERK/MAPK pathway activity via the suppression of MEK1 expression, and further suppressed proliferation of pituitary tumor cells.

[An analysis of clinical characteristics of twelve cases of mesenteric panniculitis].

Objective: Mesenteric panniculitis is an idiopathic, uncommon disease involving the adipose tissue of mesentery. The etiology, diagnosis and treatment are still unnoticed. We thus reported a case series to improve the understanding of this rare disorder. Methods: We retrospectively analyzed the clinical data of 12 patients with mesenteric panniculitis including manifestation, diagnosis, treatment and prognosis. Results: We found a male predominance (M∶F 3∶1) with the median age of 58 years old at diagnosis. The most common symptom was abdominal pain (9/12), followed by abdominal distension (3/12) and weight loss (3/12). Physical examination was unremarkable in the majority of patients (8/12). C reactive protein (9/12) and erythrocyte sedimentation rate (10/12) were normal in majority of patients. CT findings were of much diagnostic value. All patients had small intestinal mesentery involvement and multi-nodular appearance with increased fat density. Pseudo-capsule sign (8/12) and fat halo sign (6/12) were common. Pathological diagnosis was obtained in 4 cases showing fat tissue inflammation with local necrosis and fibrosis. Six cases all received prednisone, 2 with combined cyclophosphamide, 1 with azathioprine, 1 with tripterygium wilfordii. Short-term clinical response was achieved in all cases, but two patients relapsed. Conclusions: Mesenteric panniculitis occurs predominantly in middle-aged and elderly. Abdominal pain is the leading symptom. Inflammatory markers are often normal while computed tomography is the most important diagnostic tool. Surgery combined with cortical steroid and immunosuppressant agents is effective.

Immunohistochemical profiling including beta-catenin in conjunctival melanocytic lesions.

Conjunctival melanocytic lesions encompass a group of clinically diverse, benign to malignant, neoplasms that may contain overlapping histopathological features, making definitive diagnosis challenging in some cases. In this series, we compared multiple immunohistochemical (IHC) markers in 11 conjunctival nevi, 10 primary acquired melanosis (PAM) lesions, and 11 conjunctival melanomas. Immunostains included the melanocytic markers HMB-45 and Melan-A, as well as the proliferative marker Ki-67. Loss of beta-catenin expression has been associated with more aggressive clinical disease in cutaneous melanoma, but its status in conjunctival melanocytic lesions is not known, therefore we incorporated beta-catenin immunohistochemical staining in our study. In this series, conjunctival melanomas had a higher Ki-67 proliferative index and HMB-45 immunoreactivity than did PAM lesions and conjunctival nevi (P<0.001). Melan-A was highly expressed in all 3 groups. Beta-catenin was more strongly expressed in melanomas and nevi than in PAM (P<0.001). There was high inter-grader reliability (Kappa=0.53). Overall, IHC labeling of HMB-45 and Ki-67 is increased in conjunctival melanomas compared to PAM or conjunctival nevi. Beta-catenin, an IHC marker previously unstudied in conjunctival melanocytic lesions, is not preferentially expressed in benign lesions and may play a different role in conjunctival atypia than it does in cutaneous melanoma.

[A retrospective case-control study of immunoglobulin G4-related disease combined with malignancy].

IgG4-related disease (IgG4-RD) has been proved to be associated with malignancy.The incidence and risk factors of malignancy development in IgG4-RD were not clear. Nine IgG4-RD patients with malignancies and 27 IgG4-RD control cases were analyzed for risk factors and clinical features. The incidence of malignancy in IgG4-RD was 3.3%, higher than age-controlled general population. Smoking history was significantly more common in patients with malignancies than in the control group (9/9 vs 16/27, P<0.05). A total of 6/9 malignancies occurred within the first year after the diagnosis of IgG4-RD. Colorectal, biliary and thyroid cancers were the leading types. Smoking history is a risk factor for IgG4-RD associated malignancy. Careful vigilance to monitor malignancy needs to be paid during follow-up.

Phosphatidylinositol-3 kinase-dependent translational regulation of Id1 involves the PPM1G phosphatase.

Id1 is a helix-loop-helix transcriptional modulator that increases the aggressiveness of malignant glial neoplasms. Since most glioblastomas (GBMs) show increased phosphatidylinositol-3 kinase (PI-3K) signaling, we sought to determine whether this pathway regulates Id1 expression. Higher basal Id1 expression correlates with dysregulated PI-3K signaling in multiple established GBM cell lines. Further characterization of PI-3K-dependent Id1 regulation reveals that chemical or genetic inhibition of PI-3K signaling reduces Id1 protein but not mRNA expression. Overall, PI-3K signaling appears to enhance Id1 translation with no significant effect on its stability. PI-3K signaling is known to regulate protein translation through mTORC1-dependent phosphorylation of 4E-BP1, which reduces its association with and inhibition of the translation initiation factor eIF4E. Interestingly, while inhibition of PI-3K and AKT lowers 4E-BP1 phosphorylation and expression of Id1 in all cases, inhibition of TORC1 with rapamycin does not consistently have a similar effect, suggesting an alternative mechanism for PI-3K-dependent regulation of Id1 translation. We now identify a potential role for the serine-threonine phosphatase PPM1G in translational regulation of Id1 protein expression. PPM1G knockdown by siRNA increase both 4E-BP1 phosphorylation and Id1 expression and PPM1G and 4E-BP1 co-associates in GBM cells. Furthermore, PPM1G is a phosphoprotein and this phosphorylation appears to be regulated by PI-3K activity. Finally, PI-3K inhibition increases PPM1G activity when assessed by an in vitro phosphatase assay. Our findings provide the first evidence that the PI-3K/AKT signaling pathway modulates PPM1G activity resulting in a shift in the balance between hyper- and hypo-phosphorylated 4E-BP1 and translational regulation of Id1 expression.

Right miniparasternotomy may be a good minimally invasive alternative to full sternotomy for cardiac valve operations: a propensity-adjusted analysis.

BACKGROUND: Limited real-world data existed for mini-parasternotomy approach with good sample size in Asian cohorts and most previous studies were eclipsed by case heterogeneity. The goal of this study was to compare safety and quality outcomes of cardiac non-coronary valve operations by mini-parasternotomy and full sternotomy approaches on risk-adjusted basis. METHODS From our hospital database, we retrieved the cases of non-coronary valve operations from 1 January 2005 to 31 December 2012, including re-do, emergent, and combined procedures. Estimated EuroScore-II and propensity score for choosing mini-parasternotomy were adjusted for in the regression models on hospital mortality, complications (pneumonia, stroke, sepsis, etc.), and quality parameters (length of stay, ICU time, ventilator time, etc.). Non-complicated cases, defined as survival to discharge, ventilator use not over one week, and intensive care unit stay not over two weeks, were used for quality parameters. RESULTS: There were 283 mini-parasternotomy and 177 full sternotomy cases. EuroScore-II differed significantly (medians 2.1 vs. 4.7, P<0.001). Propensity scores for choosing mini-parasternotomy were higher with lower EuroScore-II (OR=0.91 per 1%, P<0.001), aortic regurgitation (OR=2.3, P=0.005), and aortic non-mitral valve disease (OR=3.9, P<0.001). Adjusted for propensity score and EuroScore-II, mini-parasternotomy group had less pneumonia (OR=0.32, P=0.043), less sepsis (OR=0.31, P=0.045), and shorter non-complicated length of stay (coefficient=-7.2 (day), P<0.001) than full sternotomy group, whereas Kaplan-Meier survival, non-complicated ICU time, non-complicated ventilator time, and 30-day mortality did not differ significantly. CONCLUSION: The propensity-adjusted analysis demonstrated encouraging safety and quality outcomes for mini-parasternotomy valve operation in carefully selected patients.

MicroRNA-219-5p functions as a tumor suppressor partially by targeting platelet-derived growth factor receptor alpha in colorectal cancer.

Platelet-derived growth factor receptor (PDGFR) signaling pathway was involved in the progress of colorectal cancer (CRC). By using the bioinformatic system online, we found that PDGFRα is a potential target of miR-219-5p. However, the expression pattern and underlying mechanisms of miR-219-5p had not been elucidated in CRC. Herein, we first evaluated the expression of miR-219-5p in tumor tissues by real-time polymerase chain reaction. Next, we confirmed that PDGFRα is the target of miR-219-5p by using luciferase report. And then, we investigated the biological functions of miR-219-5p in vitro in cell proliferation and apoptosis as well as cell cycle by gain and loss of function strategies. Data shown that miR-219-5p is down-regulated in CRC tissues compared with the corresponding matched normal tissues. PDGFRα was a direct target of miR-219-5p. Overexpression of miR-219-5p could inhibit cell proliferation, promote cell apoptosis and induce cell cycle arrest at the G1 phase. Furthermore, miR-219-5p suppressed the activation of the phosphatidylinositol 3-kinase/Akt signaling pathway and downregulated G1 cell-cycle-related protein cyclin D1, cyclin-dependent kinase (CDK) 4, and CDK6. Taken together, our results demonstrate that miR-219-5p functions as a tumor suppressor partially by targeting PDGFRα in colorectal cancer.

Hypoxia upregulates Rab11-family interacting protein 4 through HIF-1α to promote the metastasis of hepatocellular carcinoma.

Hypoxic microenvironment is a powerful driving force for the invasion and metastasis of hepatocellular carcinoma (HCC). Hypoxia-inducible factor 1α (HIF-1α), as a crucial regulator of transcriptional responses to hypoxia, induces the expression of multiple target genes involved in different steps of HCC metastatic process. It is critical to find target genes associated with metastasis under hypoxia for shedding new light on molecular mechanism of HCC metastasis. In this study, we uncovered that hypoxia could induce the upregulation of Rab11-family interacting protein 4 (Rab11-FIP4) and activation of Rab11-FIP4 promoter by HIF-1α. The overexpression of Rab11-FIP4 significantly enhanced the mobility and invasiveness of HCC cells in vitro, also contributed to distant lung metastasis in vivo, whereas silencing of Rab11-FIP4 decreased the ability of migration and invasion in HCC cells in vitro and suppressed lung metastasis in vivo. Rab11-FIP4 facilitated HCC metastasis through the phosphorylation of PRAS40, which was regulated by mTOR. Furthermore, the expression level of Rab11-FIP4 was significantly increased in HCC tissues and high expression of Rab11-FIP4 was closely correlated with vascular invasion and poor prognosis in HCC patients. A markedly positive correlation between the expression of Rab11-FIP4 and HIF-1α was observed in HCC tissues and combination of Rab11-FIP4 and HIF-1α was a more valuable predictor of poor prognosis for HCC patients. In conclusion, Rab11-FIP4 is a target gene of HIF-1α and has a pro-metastatic role in HCC, suggesting that Rab11-FIP4 may be a promising candidate target for HCC treatment.

Engineering tobacco to remove mercury from polluted soil.

Tobacco is an ideal plant for modification to remove mercury from soil. Although several transgenic tobacco strains have been developed, they either release elemental mercury directly into the air or are only capable of accumulating small quantities of mercury. In this study, we constructed two transgenic tobacco lines: Ntk-7 (a tobacco plant transformed with merT-merP-merB1-merB2-ppk) and Ntp-36 (tobacco transformed with merT-merP-merB1-merB2-pcs1). The genes merT, merP, merB1, and merB2 were obtained from the well-known mercury-resistant bacterium Pseudomonas K-62. Ppk is a gene that encodes polyphosphate kinase, a key enzyme for synthesizing polyphosphate in Enterobacter aerogenes. Pcs1 is a tobacco gene that encodes phytochelatin synthase, which is the key enzyme for phytochelatin synthesis. The genes were linked with LP4/2A, a sequence that encodes a well-known linker peptide. The results demonstrate that all foreign genes can be abundantly expressed. The mercury resistance of Ntk-7 and Ntp-36 was much higher than that of the wild type whether tested with organic mercury or with mercuric ions. The transformed plants can accumulate significantly more mercury than the wild type, and Ntp-36 can accumulate more mercury from soil than Ntk-7. In mercury-polluted soil, the mercury content in Ntp-36's root can reach up to 251 µg/g. This is the first report to indicate that engineered tobacco can not only accumulate mercury from soil but also retain this mercury within the plant. Ntp-36 has good prospects for application in bioremediation for mercury pollution.

The construction of an engineered bacterium to remove cadmium from wastewater.

The removal of cadmium (Cd) from wastewater before it is released from factories is important for protecting human health. Although some researchers have developed engineered bacteria, the resistance of these engineered bacteria to Cd have not been improved. In this study, two key genes involved in glutathione synthesis (gshA and gshB), a serine acetyltransferase gene (cysE), a Thlaspi caerulescens phytochelatin synthase gene (TcPCS1), and a heavy metal ATPase gene (TcHMA3) were transformed into Escherichia coli BL21. The resistance of the engineered bacterium to Cd was significantly greater than that of the initial bacterium and the Cd accumulation in the engineered bacterium was much higher than in the initial bacterium. In addition, the Cd resistance of the bacteria harboring gshB, gshA, cysE, and TcPCS1 was higher than that of the bacteria harboring gshA, cysE, and TcPCS1. This finding demonstrated that gshB played an important role in glutathione synthesis and that the reaction catalyzed by glutathione synthase was the limiting step for producing phytochelatins. Furthermore, TcPCS1 had a greater specificity and a higher capacity for removing Cd than SpPCS1, and TcHMA3 not only played a role in T. caerulescens but also functioned in E. coli.

Tobacco arabinogalactan protein NtEPc can promote banana (Musa AAA) somatic embryogenesis.

Banana is an important tropical fruit worldwide. Parthenocarpy and female sterility made it impossible to improve banana varieties through common hybridization. Genetic transformation for banana improvement is imperative. But the low rate that banana embryogenic callus was induced made the transformation cannot be performed in many laboratories. Finding ways to promote banana somatic embryogenesis is critical for banana genetic transformation. After tobacco arabinogalactan protein gene NtEPc was transformed into Escherichia coli (DE3), the recombinant protein was purified and filter-sterilized. A series of the sterilized protein was added into tissue culture medium. It was found that the number of banana immature male flowers developing embryogenic calli increased significantly in the presence of NtEPc protein compared with the effect of the control medium. Among the treatments, explants cultured on medium containing 10 mg/l of NtEPc protein had the highest chance to develop embryogenic calli. The percentage of lines that developed embryogenic calli on this medium was about 12.5 %. These demonstrated that NtEPc protein can be used to promote banana embryogenesis. This is the first paper that reported that foreign arabinogalactan protein (AGP) could be used to improve banana somatic embryogenesis.