Modulation of energy homeostasis in maize and Arabidopsis to develop lines tolerant to drought, genotoxic and oxidative stresses

Abiotic stresses cause crop losses worldwide that reduce the average yield by more than 50%. Due to the high energy consumed to enhance the respiration rates, the excessive reactive oxygen species release provokes cell death and, ultimately, whole plant decay. A metabolic engineering approach in maize (Zea mays) altered the expression of two poly(ADP-ribosyl)ation metabolic pathway proteins, poly(ADP-ribose) polymerase (PARP) and ADP-ribose-specifIc Nudix hydrolase (NUDX) genes that play a role in the maintenance of the energy homeostasis during stresses. By means of RNAi hairpin silencing and CRISPR/Cas9 gene editing strategies, the PARP expression in maize was downregulated or knocked down. The Arabidopsis NUDX7 gene and its two maize homologs, ZmNUDX2 and ZmNUDX8, were overexpressed in maize and Arabidopsis. Novel phenotypes were observed, such as significant tolerance to oxidative stress and improved yield in Arabidopsis and a trend of tolerance to mild drought stress in maize and in Arabidopsis. Key words: poly(ADP-ribose) polymerase, Nudix hydrolase, CRISPR/Cas9, maize, oxidative stress, drought stress

Increased MicroRNA-34b and -34c Predominantly Expressed in Stromal Tissues Is Associated with Poor Prognosis in Human Colon Cancer

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Basic Study of Susceptibility-Weighted Imaging at 1.5T

With the aim of sequence optimization in susceptibility-weighted imaging (SWI), 2 image acquisition parameters (slice thickness and matrix size) and 2 image processing conditions (number of slices per minimum intensity projection (MIP) and Sliding Window) were investigated using a 1.5-T magnetic resonance imaging (MRI) system. The subjects were 12 healthy volunteers and the target region for scanning was the whole brain. Informed consent was obtained from all subjects. First, susceptibility-weighted images were acquired with various slice thicknesses from 1mm to 5mm and various matrix sizes from 256x256 to 512x512, and the images were assessed in terms of the contrast-to-noise ratio (CNR) and were also visually evaluated by three radiologists. Then, the number of slices per MIP and the usefulness of the Sliding Window were investigated. In the study of the optimal slice thickness and matrix size, the results of visual evaluation suggested that a slice thickness of 3mm and a matrix size of 448x448 are optimal, while the results of evaluation based on CNR were not significant. As regards the image processing conditions, the results suggested that the number of slices per MIP should be set to a minimum value of 2 and that the use of Sliding Window is effective. The present study provides useful reference data for optimizing SWI sequences.</p

STUDENT TEAM ACHIEVEMENT DIVISION (STAD) TECHNIQUE IN TEACHING READING COMPREHENSION

Due to students’ problems and difficulties to learn English text, it is the teachers’ job to choose a suitable method in teaching reading comprehension. Student Team Achievement Division (STAD) is one method that is considered appropriate in making the students feel happy and enjoy their learning. When they are taught by using an enjoyable method, they will be able to enrich their reading comprehension easily and, in turn, they are expected to be able to master reading comprehension well. The problem and difficulties in learning reading comprehension were faced by the students at MTs Aswaja Tunggangri Kalidawir, and, thus, a study aimed at knowing the effectiveness of student team achievement division (STAD) technique in teaching reading comprehension was conducted in this school. The research design of this research was Pre-experimental design. The research finding in this research showed the difference between the averages of students’ score reading comprehension when they were taught without student team achievement division (STAD) technique (72,55 %) and when they were taught using student team achievement division (STAD) technique (77,6 %). Statistical calculation using T-test showed that the score of T count (10.254) was greater than that of T table (1.725) with significant level 5 % and degree of freedom of 32. It was concluded that student team achievement division (STAD) technique is an effective method in teaching reading comprehension to junior high school, especially for eight grade at MTs Aswaja Tunggangri Kalidawir