Senescence and oxidative stress in wallflowers and Arabidopsis

Reactive oxygen species (ROS) together with other signalling molecules including phytohormones regulate plant growth and senescence as well as responses to abiotic stress and pathogens. One aim of this thesis was to investigate how ROS and phytohormones regulate progression of senescence in wallflower petals. A second aim of this thesis was to investigate how SAG21, previously found to be elevated in wallflower petals, functions during development, senescence and stress in the model plant, Arabidopsis thaliana. In wallflowers (Chapter 3), onset of petal senescence was characterized by a rise in ethylene and auxin, followed by ROS accumulation. In parallel, transcript levels for markers of senescence, ethylene biosynthesis and auxin-response also increased with age. However, SAG21 peaked earlier, before visible senescence. Treatments that aimed to increase cytokinin levels or reduce ethylene delayed progression of senescence and time to petal abscission compared to controls. In contrast, ethylene hastened both processes. Marker genes analysed displayed differential expression patterns. Patterns of ROS-related enzyme activity (catalase, ascorbate peroxidase and superoxide dismutase) were also investigated in relation to wallflower petal and leaf senescence. SAG21 (previously named AtLEA5 in Arabidopsis) belongs to the late embryogenesis- associated (LEA) protein family, implicated in growth and redox responses. A SAG21-YFP fusion was localized to Arabidopsis mitochondria (Chapter 4). Over-expression (OEX) of SAG21 in Arabidopsis resulted in increased root and shoot biomass, whereas antisense (AS) lines exhibited reduced biomass. Root and shoot development, flowering and senescence were altered in transgenic lines. Transgenic lines exhibited marked root hair phenotypes (Chapter 5). Abiotic stress induced stress induced SAG21 expression in roots but not leaves. Growth of B. cinerea and of a virulent bacterial pathogen {Pseudomonas syringae pv. tomato) was affected by SAG21 expression, however growth of an avirulent P.syringae strain was unaffected (Chapter 6). These data show that SAG21 is regulated by a complex signalling network.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Senescence and oxidative stress in wallflowers and Arabidopsis

Reactive oxygen species (ROS) together with other signalling molecules including phytohormones regulate plant growth and senescence as well as responses to abiotic stress and pathogens. One aim of this thesis was to investigate how ROS and phytohormones regulate progression of senescence in wallflower petals. A second aim of this thesis was to investigate how SAG21, previously found to be elevated in wallflower petals, functions during development, senescence and stress in the model plant, Arabidopsis thaliana. In wallflowers (Chapter 3), onset of petal senescence was characterized by a rise in ethylene and auxin, followed by ROS accumulation. In parallel, transcript levels for markers of senescence, ethylene biosynthesis and auxin-response also increased with age. However, SAG21 peaked earlier, before visible senescence. Treatments that aimed to increase cytokinin levels or reduce ethylene delayed progression of senescence and time to petal abscission compared to controls. In contrast, ethylene hastened both processes. Marker genes analysed displayed differential expression patterns. Patterns of ROS-related enzyme activity (catalase, ascorbate peroxidase and superoxide dismutase) were also investigated in relation to wallflower petal and leaf senescence. SAG21 (previously named AtLEA5 in Arabidopsis) belongs to the late embryogenesis- associated (LEA) protein family, implicated in growth and redox responses. A SAG21-YFP fusion was localized to Arabidopsis mitochondria (Chapter 4). Over-expression (OEX) of SAG21 in Arabidopsis resulted in increased root and shoot biomass, whereas antisense (AS) lines exhibited reduced biomass. Root and shoot development, flowering and senescence were altered in transgenic lines. Transgenic lines exhibited marked root hair phenotypes (Chapter 5). Abiotic stress induced stress induced SAG21 expression in roots but not leaves. Growth of B. cinerea and of a virulent bacterial pathogen {Pseudomonas syringae pv. tomato) was affected by SAG21 expression, however growth of an avirulent P.syringae strain was unaffected (Chapter 6). These data show that SAG21 is regulated by a complex signalling network.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Senescence and oxidative stress in wallflowers and Arabidopsis

Reactive oxygen species (ROS) together with other signalling molecules including phytohormones regulate plant growth and senescence as well as responses to abiotic stress and pathogens. One aim of this thesis was to investigate how ROS and phytohormones regulate progression of senescence in wallflower petals. A second aim of this thesis was to investigate how SAG21, previously found to be elevated in wallflower petals, functions during development, senescence and stress in the model plant, Arabidopsis thaliana. In wallflowers (Chapter 3), onset of petal senescence was characterized by a rise in ethylene and auxin, followed by ROS accumulation. In parallel, transcript levels for markers of senescence, ethylene biosynthesis and auxin-response also increased with age. However, SAG21 peaked earlier, before visible senescence. Treatments that aimed to increase cytokinin levels or reduce ethylene delayed progression of senescence and time to petal abscission compared to controls. In contrast, ethylene hastened both processes. Marker genes analysed displayed differential expression patterns. Patterns of ROS-related enzyme activity (catalase, ascorbate peroxidase and superoxide dismutase) were also investigated in relation to wallflower petal and leaf senescence. SAG21 (previously named AtLEA5 in Arabidopsis) belongs to the late embryogenesis- associated (LEA) protein family, implicated in growth and redox responses. A SAG21-YFP fusion was localized to Arabidopsis mitochondria (Chapter 4). Over-expression (OEX) of SAG21 in Arabidopsis resulted in increased root and shoot biomass, whereas antisense (AS) lines exhibited reduced biomass. Root and shoot development, flowering and senescence were altered in transgenic lines. Transgenic lines exhibited marked root hair phenotypes (Chapter 5). Abiotic stress induced stress induced SAG21 expression in roots but not leaves. Growth of B. cinerea and of a virulent bacterial pathogen {Pseudomonas syringae pv. tomato) was affected by SAG21 expression, however growth of an avirulent P.syringae strain was unaffected (Chapter 6). These data show that SAG21 is regulated by a complex signalling network

Influence of leadership emotional intelligence on employees' job satisfaction in the Malaysian public sector

The main purpose of this study was to determine the relationship between emotional intelligence and employees' job satisfaction in the Malaysian public sector. Result of this study found that leadership emotional intelligence has a moderate relationship with employee job satisfaction. The study also found that there is no significant difference on gender perception of their leader's emotional intelligence in that both male and female employees perceive their leaders as having a moderately high level of emotional intelligence. This shows that leaders in the public service are able to utilize their emotional intelligence to understand, manage and have a good relationship with their employees. More so, these leaders seem to be able to express positive emotions, thoughts and attitude towards their employees making their employees feel satisfied at the workplace

Utilization of Low-grade Iron Ore in Ammonia Decomposition

AbstractDue to its cleanliness, fast energy cycle, and convenience of energy conversion, hydrogen has been regarded as the new energy source. Conventional process to produce hydrogen yield large amount of CO as byproduct. Moreover, the hydrogen storage and transportation have become the drawbacks in hydrogen economy. Thus, there has been increased interest in the hydrogen transportation medium as alternatives from the conventional process to produce and transport hydrogen. Ammonia has drawn worldwide attention as the most reliable hydrogen transportation medium. Through the decomposition of ammonia, hydrogen and nitrogen gas were produces as the byproduct without any CO or CO2 emission. In this experiment, the ore were introduced as the medium for ammonia decomposition. The ore were put into quartz tube reactor and were dehydrated at 400°C for 1 hour, then hydrogen reduced for 2hours before and undergone ammonia decomposition at 500-700°C for 3hours. The effects of temperature to the % conversion of ammonia decomposition were also studied. Ammonia decomposition at higher temperature gives higher conversion. As seen in the results, the NH3 conversion decreased with increasing time and the value after 3hours of reaction increased in the sequence of 500°C<600°C< 700°C. During ammonia decomposition, nitriding of iron occurred. The relation between temperature and the nitriding potential, KN is also investigated. The purpose of this study is to investigate the utilization of low-grade ore as medium for ammonia decomposition to produce hydrogen

Bio-succinic acid production: Escherichia coli strains design from genome-scale perspectives

Escherichia coli (E. coli) has been established to be a native producer of succinic acid (a platform chemical with different applications) via mixed acid fermentation reactions. Genome-scale metabolic models (GEMs) of E. coli have been published with capabilities of predicting strain design strategies for the production of bio-based succinic acid. Proof-of-principle strains are fundamentally constructed as a starting point for systems strategies for industrial strains development. Here, we review for the first time, the use of E. coli GEMs for construction of proof-of-principles strains for increasing succinic acid production. Specific case studies, where E. coli proof-of-principle strains were constructed for increasing bio-based succinic acid production from glucose and glycerol carbon sources have been highlighted. In addition, a propose systems strategies for industrial strain development that could be applicable for future microbial succinic acid production guided by GEMs have been presented

Strength, water absorption and thermal comfort of mortar bricks containing crushed ceramic waste

This present study investigated the crushed ceramic waste utilisation as sand replacement in solid mortar bricks. The percentage of crushed ceramic waste used were 0% (CW0), 10% (CW10), 20% (CW20) and 30% (CW30) from the total weight of sand. The dimension prescribed of mortar bricks are 215 mm x 102.5 mm x 65 mm as followed accordance to MS 2281:2010 and BS EN 771-1:2011+A1:2015. Four (4) tests were conducted on mortar bricks namely crushing strength, water absorption, compressive strength of masonry units and thermal comfort. The incorporation of ceramic waste in all designated mortar bricks showed the increment of crushing strength between 23% and 46% at 28 days of curing and decrement water absorption between 34% and 44% was recorded corresponding to control mortar bricks. The prism test of masonry units consists of mortar bricks containing ceramic waste indicated the high increment of compressive strength at about 200% as compared to mortar brick without ceramic waste. The thermal comfort test of ceramic mortar bricks were also showed the good insulation with low interior temperature. Therefore, the ceramic waste can be utilised as a material replacement to fine aggregate in mortar brick productions due to significant outcomes performed

Chemical composition of eurycoma longifolia (Tongkat Ali) and the quality control of its herbal medicinal products

Eurycoma longifolia which is known as Tongkat Ali is commonly found in Asian countries such as Malaysia, Indonesia, Thailand, Myanmar and Cambodia. This plant is famously known for its various pharmacological activities. The plant is also reported to consist of various types of important bioactive compounds such as quassinoids, canthine-6-one alkaloids, triterpenes, squalene derivatives, $-carboline alkaloids etc which are mostly found in the root part. The presence of these important phytochemicals contributes to their different types of therapeutic effects more especially in terms of aphrodisiac properties which have resulted in a massive increase in demand and production of their Herbal Medicinal Products (HMP). These situations have resulted in the production of E. longifolia HMPs whose quality are questionable, which might be as a result of restricted of sources that might lead to some unethical activities carried out by suppliers and manufacturers in order to gain more profit. Therefore, this review focused on adulteration issues such as contamination and substitution of E. longifolia HMP. The review also includes the possible solutions on how to improve the quality of these HMP so as they can be safe for consumption. Embracing pharmacovigilance in the preparation of the HMP, proper implementation of agricultural practices such as Good Agricultural and Collection Practices (GACP) and Good Manufacturing Practices (GMP) together with the establishment of effective regulatory bodies would undoubtedly improve the quality of E. longifolia HMP sold in the market. The detailed knowledge about the main composition of the E. longifolia HMP will help to ascertain their quality, efficacy and safety as these are very important toward quality control

Review: DNA Barcoding and Chromatography Fingerprints for the Authentication of Botanicals in Herbal Medicinal Products

In the last two decades, there has been a tremendous increase in the global use of herbal medicinal products (HMPs) due to their claimed health benefits. This has led to increase in their demand and consequently, also, resulted in massive adulteration. This is due to the fact that most of the traditional methods cannot identify closely related species in a process product form. Therefore the urgent need for simple and rapid identification methods resulted in the discovery of a novel technique. DNA barcoding is a process that uses short DNA sequence from the standard genome for species identification. This technique is reliable and is not affected by external factors such as climates, age, or plant part. The difficulties in isolation of DNA of high quality in addition to other factors are among the challenges encountered using the DNA barcoding in the authentication of HMP. These limitations indicated that using DNA barcoding alone may ineffectively authenticate the HMP. Therefore, the combination of DNA barcoding with chromatographic fingerprint, a popular and generally accepted technique for the assessment and quality control of HMP, will offer an efficient solution to effectively evaluate the authenticity and quality consistency of HMP. Detailed and quality information about the main composition of the HMPs will help to ascertain their efficacy and safety as these are very important for quality control