Good quality deoxyribonucleic acid (DNA) is the pre-requisite for its downstream applications. The presence of high concentrations of polysaccharides, polyphenols, proteins, and other secondary me- tabolites in mango leaves poses problem in getting good quality DNA fit for polymerase chain reaction (PCR) applications. The problem is exacerbated when DNA is extracted from mature mango leaves. A reliable and modified protocol based on the cetyl- trimethylammonium bromide (CTAB) method for DNA extraction from mature mango leaves is described here. High concentrations of inert salt were used to remove polysaccharides; Polyvinylpyrrolidone (PVP) and β-mercaptoethanol were employed to manage phenolic compounds. Extended chloroform-isoamyl alcohol treatment followed by RNase treatment yielded 950?1050 μg of good quality DNA, free of protein and RNA. The problems of DNA degradation,contamination, and low yield due to irreversible binding of phenolic compounds and coprecipitation of polysaccharides with DNA were avoided by this method. The DNA isolated by the modified method showed good PCR amplification using simple se- quence repeat (SSR) primers. This modified protocol can also be used to extract DNA from other woody plants having similar problems. 相似文献
Educational Research for Policy and Practice - Much has been written, published, and presented about the important role and uses of technology in English language teaching (ELT) today and the... 相似文献
The present study explored the direct and indirect (serial multiple mediation of math self-efficacy and math enjoyment) effects of perceived parental math support on middle school students’ math engagement. A total of 374 middle school students ranging the age of 11 to 15 years completed a set of questionnaires assessing perceived parental math support, math self-efficacy, math enjoyment, and math engagement. In the analysis of structural model, a multiple-step multiple mediation analysis was employed. The findings indicated that perceived parental math support was directly and positively associated with math engagement. Additionally, math self-efficacy and math enjoyment sequentially mediated the relationship between parental math support and math engagement. The limitations and implications of the results are discussed and suggestions for future research are proposed.
ABSTRACTContemporary anti-Islamic discourses in Australia construct Islam as an uncivilised belief system and its Muslim followers as homogenous unassimilable Others. Within these discourses, the diversity among Muslim women has been overshadowed, and they are constructed as a monolithic ‘veiled’ woman. Drawing on 20 conversational interviews with veiled and unveiled Australian Muslim women from various cultural backgrounds, this paper explores the diverse ways in which Muslim women resist and challenge anti-Islamic discourses on Islam, Muslims and Muslim women. Guided by intersectional theories on identity and resistance, our analysis show that the women drew on discursive and performative strategies to contest anti-Islamic representations that homogenise and vilify Muslims and construct Muslim women as veiled and oppressed. The findings also show that the ways in which women contested hegemonic anti-Islamic representations were diverse and informed by intersecting power and social locations, including race, ethnicity, gender and sexuality. Implications for research on resistance and identity negotiations of minority groups are discussed. 相似文献
The purpose of the current study was to investigate the effectiveness of interacting with animations using mobile devices on grade 12 students’ spatial and reasoning abilities. The study took place in a grade 12 context in Oman. A quasi-experimental design was used with an experimental group of 32 students and a control group of 28 students. The experimental group studied chemistry using mobile tablets that had a digital instructional package with different animation and simulations. There was one tablet per student. A spatial ability test and a scientific reasoning test were administered to both groups prior and after the study, which lasted for 9 weeks. The findings showed that there were significant statistical differences between the two groups in terms of spatial ability in favour of the experimental group. However, there were no differences between the two groups in terms of reasoning ability. The authors reasoned that the types of animations and simulations used in the current study featured a wide range of three-dimensional animated illustrations at the particulate level of matter. Most probably, this decreased the level of abstractness that usually accompanies chemical entities and phenomena and helped the students to visualize the interactions between submicroscopic entities spatially. Further research is needed to decide on types of scientific animations that could help students improve their scientific reasoning. 相似文献
Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X. nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage. 相似文献