Improvement of abiotic stress tolerance and calcium-deficiency disorder resistance of tomato plants

Doctor of PhilosophyDepartment of Horticulture, Forestry, and Recreation ResourcesSunghun ParkPlants are continuously exposed to numerous abiotic stresses, which adversely affect plant growth, development, and yield. Plants have developed different signaling pathways to cope with abiotic stresses, and some of the pathways converge to help plants tolerate simultaneous stresses. Here, we report ectopic expression of an Arabidopsis glutaredoxin AtGRXS17 that confers tolerance to multiple abiotic stresses in tomato plants. In yeast assays, AtGRXS17 co-localized with yeast ScGrx3 in the nucleus and suppressed the sensitivity of yeast grx3grx4 double mutants to oxidative stress and heat shock. In plants, GFP-AtGRXS17 fusion proteins initially localized in the cytoplasm but migrated to the nucleus during heat stress. Ectopic expression of AtGRXS17 in tomato plants minimized photo-oxidation of chlorophyll and reduced oxidative damage of cell membrane systems under heat stress. Furthermore, expression of the heat shock transcription factor (HSF) and heat shock protein (HSP) genes was up-regulated in AtGRXS17-expressing tomato plants during heat stress when compared to wild-type controls. Under cold, drought, and oxidative stress conditions, AtGRXS17-expressing tomato plants also displayed more vigorous growth and less physiological damage than those of the wild-type control plants. Quantitative real-time PCR (qRT-PCR) analysis indicated that expression of AtGRXS17 alters multiple stress defense signaling pathways, including the Abscisic Acid (ABA) and C-Repeat Binding Factors (CBF) pathways. The results revealed a conserved function for a glutaredoxin protein in abiotic stress adaptation, and manipulation of AtGRXS17 may be a useful approach to improve crop stress tolerance and understand plant signaling under abiotic stress conditions. Deregulated expression of an Arabidopsis H[superscript]+/Ca[superscript]2[superscript]+ antiporter (sCAX1) in agricultural crops increases total calcium (Ca[superscript]2[superscript]+) but may result in yield loses due to calcium-deficiency like symptoms. Here we demonstrate that co-expression of a maize calreticulin (CRT, a Ca[superscript]2[superscript]+ binding protein located at endoplasmic reticulum) in sCAX1-expressing plants mitigated these adverse effects while maintaining enhanced Ca[superscript]2[superscript]+ content. Co-expression of CRT and sCAX1 could alleviate the hypersensitivity to ion imbalance in tobacco plants. Furthermore, blossom-end rot (BER) in tomato may be linked to changes in CAX activity and enhanced CRT expression mitigated BER in sCAX1 expressing lines. These findings suggest that co-expressing Ca[superscript]2[superscript]+ transporters and binding protein at different intracellular compartments can alter the content and distribution of calcium within the plant matrix

Predicting Academic Performance via Machine Learning Methods

Machine learning has been a heavily researched area in recent years, and many machine-learning methods for data analysis have been proposed in literature. The goal of this research was to explore various machine-learning methods for the purpose of predicting the future performance of Electrical Engineering majors based on their academic records from the common year in the College of Engineering. Machine-learning methods make predictions solely based on historical data, and no external biases are involved in the decision-making process. Therefore, such predictions can be much more objective than those offered through in-person meeting and “eyeball” tests. In our work, we used the final grades from ECEN 214 Electrical Circuit Theory as the primary indicator of future performance. Our research showed that both the Naïve Bayesian and Random Forest methods could lead to accurate predictions of the ECEN 214 final grade based on the student’s academic records from the common year. Our research also revealed the courses that have the most predictive power in the future performance of Electrical Engineering majors

Construction of Clinical Biobanks and the Medical Ethics

Nowadays, various types and forms of clinical biobanks have been gradually established worldwide, which have become one of the important components and research platforms of life science and related disease researches in the medical system. This article mainly introduces the construction, management and operation of clinical biobanks, and discusses the medical ethics faced by it

Effect of dry-wet cycles on dynamic properties and microstructures of sandstone: Experiments and modelling

Underground pumped storage power plant (UPSP) is an innovative concept for space recycling of abandoned mines. Its realization requires better understanding of the dynamic performance and durability of reservoir rock. This paper conducted ultrasonic detection, split Hopkinson pressure bar (SHPB) impact, mercury intrusion porosimetry (MIP), and backscatter electron observation (BSE) tests to investigate the dynamical behaviour and microstructure of sandstone with cyclical dry-wet damage. A coupling FEM-DEM model was constructed for reappearing mesoscopic structure damage. The results show that dry-wet cycles decrease the dynamic compressive strength (DCS) with a maximum reduction of 39.40%, the elastic limit strength is reduced from 41.75 to 25.62 MPa. The sieved fragments obtain the highest crack growth rate during the 23rd dry-wet cycle with a predictable life of 25 cycles for each rock particle. The pore fractal features of the macropores and micro-meso pores show great differences between the early and late cycles, which verifies the computational statistics analysis of particle deterioration. The numerical results show that the failure patterns are governed by the strain in pre-peak stage and the shear cracks are dominant. The dry-wet cycles reduce the energy transfer efficiency and lead to the discretization of force chain and crack fields

On the Construction of Biobank in General Hospitals

Objective: Discussion on a series of biospecimen related issues are conducted, such as collection and preservation, quality control, as well as management and application, during the construction of human tissue biobank in a general hospital. Methods: To develop a set of standardized operational procedures and to collect tissue samples, such as whole blood, serum, plasma, fresh frozen tissues, cerebrospinal fluid, and paraffin-embedded tissues, which were classified and made aliquots according to different requirements, and stored at -80℃ temperature refrigerator or in liquid nitrogen. At the same time, a set of information management software was used to realize management of the biobank. Results: Currently, there are more than 20,000 specimens of various benign and malignant cases, which cover 380 diseases, being collected in the biological database in our hospital. These specimens include paraffin-embedded tissue, fresh frozen tissue, femoral head, whole blood, plasma, serum and cerebrospinal fluid, etc. A large number of these specimensare beneficial is used in clinical research at present. Conclusion: The establishment of biological sample bank can maximize the value of non-reborn human tissue specimens, and provide normal control standards as well as benign and malignant disease standards for clinical diagnosis and treatment, which is of great significance to the research of disease pathogenesis and the development of detection technology