Effect of saline stress on the physiology and growth of maize hybrids and their related inbred lines

Salinity is one major abiotic stress that restrict plant growth and crop productivity. In maize (Zea mays L), salt stress causes significant yield loss each year. However, indices of maize response to salt stress are not completely explored and a desired method for maize salt tolerance evaluation is still not established. A Chinese leading maize variety Jingke968 showed various resistance to environmental factors, including salt stress. To compare its salt tolerance to other superior maize varieties, we examined the physiological and growth responses of three important maize hybrids and their related inbred lines under the control and salt stress conditions. By compar- ing the physiological parameters under control and salt treatment, we demonstrated that different salt tolerance mechanisms may be involved in different genotypes, such as the elevation of superoxide dismutase activity and/ or proline content. With Principal Component Analysis of all the growth indicators in both germination and seedling stages, along with the germination rate, superoxide dismutase activity, proline content, malondialdehyde content, relative electrolyte leakage, we were able to show that salt resistance levels of hybrids and their related inbred lines were Jingke968 > Zhengdan958 > X1132 and X1132M > Jing724 > Chang7-2 > Zheng58 > X1132F, respectively, which was consistent with the saline field observation. Our results not only contribute to a better understanding of salt stress response in three important hybrids and their related inbred lines, but also this evaluation system might be applied for an accurate assessment of salt resistance in other germplasms and breeding material

Contamination status and molecular typing of Legionella pneumophila in artificial water environment in Shanghai hospitals from 2019 to 2020

BackgroundThe incidence of Legionnaires' disease is increasing globally and artificial water environment is becoming a common source of outbreaks. Molecular typing techniques can help prevent and control Legionella. ObjectiveTo understand the molecular epidemiological characteristics of Legionella pneumophila in artificial water environment of Shanghai hospitals, and provide a scientific basis for the prevention and control of Legionnaires' disease. MethodsWater samples were collected from artificial water environment in 14 hospitals from May to October each year from 2019 to 2020 in Shanghai. A total of 984 water samples were collected from 8 Grade-A tertiary hospitals and 6 non-Grade-A tertiary hospitals, including 312 samples of cooling water, 72 samples of chilled water, and 600 samples of tap water. The water samples were isolated and serotyped for Legionella pneumophila and preserved, and the positive rate of Legionella pneumophila in the samples was used as an indicator of contamination. The preserved strains were resuscitated and 81 surviving strains were obtained for pulsed field gel electrophoresis (PFGE) typing analysis. ResultsA total of 124 Legionella pneumophila positive water samples were detected, with a positive rate of 12.60%. The positive rate was higher in the Grade-A tertiary hospitals (16.54%, 87/526) than in the non-Grade-A tertiary hospitals (8.08%, 37/458) (χ2=15.91, P<0.001). The positive rate of cooling water (23.40%) was the highest among different types of water samples, and the difference was statistically significant (χ2=61.19, P<0.001). The difference in positive rate of tap water was statistically significant among different hospital departments (χ2=11.37, P<0.05). The positive rate in 2019 (15.06%) was higher than that in 2020 (9.84%) (χ2=6.23, P<0.05). From May to October, August had the highest annual average positive rate (16.46%) and October had the lowest (8.54%), but the difference in positive rates among months was not statistically significant (χ2=5.39, P=0.37). The difference in positive rate among districts was statistically significant (χ2=24.88, P<0.001). A total of 131 strains of Legionella pneumophila were isolated, with serotype 1 (80.15%, 105/131) predominating. Among the 81 surviving strains of Legionella pneumophila subjected to PFGE typing, the band-based similarity coefficients ranged from 41.30% to 100%. Among the 29 PFGE band types (S1-S29) recorded, each band type included 1-10 strains, and S28 was the dominant band type. Four clusters (I-IV) of PFGE band types were identified, accounting for 66.67% (54/81) of all strains and containing 13 band types. ConclusionLegionella pneumophila contamination is present in the artificial water environment of hospitals in Shanghai from 2019 to 2020, and the contamination in tap water deserves attention. The detected serotype of Legionella pneumophila is predominantly type 1, and PFGE typing reveals the presence of genetic polymorphism. Therefore, the monitoring and control of Legionella pneumophila in hospital artificial water environment should be strengthened

Altered RECQ Helicase Expression in Sporadic Primary Colorectal Cancers

AbstractDeregulation of DNA repair enzymes occurs in cancers and may create a susceptibility to chemotherapy. Expression levels of DNA repair enzymes have been shown to predict the responsiveness of cancers to certain chemotherapeutic agents. The RECQ helicases repair damaged DNA including damage caused by topoisomerase I inhibitors, such as irinotecan. Altered expression levels of these enzymes in colorectal cancer (CRC) may influence the response of the cancers to irinotecan. Thus, we assessed RECQ helicase (WRN, BLM, RECQL, RECQL4, and RECQL5) expression in primary CRCs, matched normal colon, and CRC cell lines. We found that BLM and RECQL4 mRNA levels are significantly increased in CRC (P = .0011 and P < .0001, respectively), whereas RECQL and RECQL5 are significantly decreased (P = .0103 and P = .0029, respectively). RECQ helicase expression patterns varied between specific molecular subtypes of CRCs. The mRNA and protein expression of the majority of the RECQ helicases was closely correlated, suggesting that altered mRNA expression is the predominant mechanism for deregulated RECQ helicase expression. Immunohistochemistry localized the RECQ helicases to the nucleus. RECQ helicase expression is altered in CRC, suggesting that RECQ helicase expression has potential to identify CRCs that are susceptible to specific chemotherapeutic agents

Radiomic signature of the FOWARC trial predicts pathological response to neoadjuvant treatment in rectal cancer

Background We aimed to develop a radiomic model based on pre-treatment computed tomography (CT) to predict the pathological complete response (pCR) in patients with rectal cancer after neoadjuvant treatment and tried to integrate our model with magnetic resonance imaging (MRI)-based radiomic signature. Methods This was a secondary analysis of the FOWARC randomized controlled trial. Radiomic features were extracted from pre-treatment portal venous-phase contrast-enhanced CT images of 177 patients with rectal cancer. Patients were randomly allocated to the primary and validation cohort. The least absolute shrinkage and selection operator regression was applied to select predictive features to build a radiomic signature for pCR prediction (rad-score). This CT-based rad-score was integrated with clinicopathological variables using gradient boosting machine (GBM) or MRI-based rad-score to construct comprehensive models for pCR prediction. The performance of CT-based model was evaluated and compared by receiver operator characteristic (ROC) curve analysis. The LR (likelihood ratio) test and AIC (Akaike information criterion) were applied to compare CT-based rad-score, MRI-based rad-score and the combined rad-score. Results We developed a CT-based rad-score for pCR prediction and a gradient boosting machine (GBM) model was built after clinicopathological variables were incorporated, with improved AUCs of 0.997 [95% CI 0.990–1.000] and 0.822 [95% CI 0.649–0.995] in the primary and validation cohort, respectively. Moreover, we constructed a combined model of CT- and MRI-based radiomic signatures that achieve better AIC (75.49 vs. 81.34 vs.82.39) than CT-based rad-score (P = 0.005) and MRI-based rad-score (P = 0.003) alone did. Conclusions The CT-based radiomic models we constructed may provide a useful and reliable tool to predict pCR after neoadjuvant treatment, identify patients that are appropriate for a 'watch and wait' approach, and thus avoid overtreatment. Moreover, the CT-based radiomic signature may add predictive value to the MRI-based models for clinical decision making

Implications of Epigenetic Drift in Colorectal Neoplasia

NIH grants U01CA182940 (G.E. Luebeck, W.D. Hazelton, W.M. Grady, S.K. Madden, K. Curtius), U01CA199336 (G.E. Luebeck, W.D. Hazelton); Barts Charity grant 472-2300, London (K. Curtius) and UK Medical Research Council Rutherford fellowship (K. Curtius); and NIH grants (P30CA15704, U01CA152756, R01CA194663, R01CA220004, U54CA143862, P01CA077852),R.A.C.E. Charities, Cottrell Family Fund, R03CA165153, Listwin Family Foundation, Seattle Translational Tumor Research program, Fred Hutchinson Cancer Research Center (S.K. Madden, M. Yu, K.T. Carter, and W.M. Grady), R01CA189184 (C. Lee, C.M. Ulrich, S.K.Madden, M. Yu, K.T. Carter, and W.M. Grady), R01CA112516, R01CA114467, R01CA120523 (C.M. Ulrich, S.K. Madden, M. Yu, K.T. Carter, and W.M. Grady), Huntsman Cancer Foundation, U01 CA206110, R01CA189184 R01CA 207371 and P30CACA042014 (C.M. Ulrich). U24CA074794 (P.A. Newcomb, S.K. Madden, M. Yu, K.T. Carter, and W.M. Grady). This material is the result of work supported in part by resources from the VA Puget Sound Health Care System and the ColoCare Study

Speciation of trace metals in natural waters

The speciation of trace metals in natural waters has been extensively studied owing to their potential effects on geochemical, biological and environmental processes. Chemical speciation modeling provides a useful approach to interpret and predict the speciation of trace metals in natural waters. This dissertation focuses on examining the ionic interactions between trace metals and inorganic ligands in natural waters using ionic interaction model. The models include ion pairing and specific interactions of metals and ligands. The models can be used to examine the interactions of ions as a function of ionic strength and temperature. The models require reliable stability constants (beta *n) for the formation of metal complexes over a wide range of temperature (0 to 50°C) and ionic strength (0 to 6 m). At the present the knowledge on effect of ionic strength and temperature on the stability constants is limited. This study examines the interaction of the trace metals (Mn2+, YREE and Pb2+) with inorganic ligands (CO32-, F and Cl-) over a wide range of temperature and ionic strength. These studies include: (1) Solubility of Rhodochrosite (MnCO3) in NaCl solutions (Journal of Solution Chemistry, 2003, 32 , 405--416) (2) Effects of temperature and ionic strength on the stabilities of the first and second fluoride complexes of yttrium and the rare earth elements (Geochim. Cosmochim. Acta, 2004, 68, 4301--4308) (3) Stability constants for the formation of lead chloride complexes as a function of temperature and ionic strength (Geochim. Cosmochim. Acta, in press)Different techniques (solubility measurements, cation exchange on resins, and spectrophotometry) were used to determine the stability constants of the metal complexes as a function of temperature (0 to 50°C) and ionic strength (0 to 6 m). The temperature effect has been examined using the Van\u27t Hoff equation to determine the enthalpies for the formation of the metal complexes. The measurements as a function of ionic strength have been analyzed using ion pairing and the Pitzer specific interaction models. The resulting Pitzer coefficients and stability constants of the metal complexes can be used in ionic interaction models to better understand metal speciation in natural waters over a wide range of temperature and ionic strength