Cyanobacteria as photosynthetic factories: Synthetic biology methods in the development of next-generation production platforms

The aim of the project is to use synthetic biology to generate improved cyanobacterial cell factories for the production of desired metabolites directly from CO2 and water using sun as the sole energy source with the emphasis specifically on the production efficiency of the systems. Importantly, the project generates a framework which can be used to assemble and optimize many different kinds of pathways in the cyanobacterial host Synechocystis sp PCC 6803. Significant effort has been placed on the development of assembly systems and characterization of carefully selected genetic components in Synechocystis. This system allows (i) flexible assembly of complex expression constructs in a relatively high throughput manner, (ii) quantitative evaluation of the systems in vivo using selected fluorescent markers, (iii) generation of optimized synthetic pathways with validated genetic regulatory systems. This study combines the power of the synthetic biology tools developed in the current work, and bioinformatics analysis of potential pathways to generate potentially interesting end-product

SOFT TISSUE GROWTH & REMODELLING: APPLICATION IN LEFT VENTRICLE POSTMYOCARDIAL INFARCTION

Cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity today, myocardial infarction (MI) an effect of IschaemicHeartDisease (IHD) contributes to the majority of such cases, accounting for upto 31 % of global mortality. Advancements in medical diagnostics, interventions, therapies and prognosis are hindered by the complex dynamics within tissuemicro-structure due to observed changes after the onset of a disease. Modelling and simulation of soft tissue growth and remodelling proves to be a significant tool to simulate instances of disease progression and provide results helpful towards the medical field. A 1D novel constrained mixture model of the left ventricular myocardiumis presented using an incompressible, isotropic, elastic, sphericalmembrane approximation, taking into consideration the micro-structural constituents i.e. ground matrix, cardiomyocytes and collagen fibres. The constituents are assigned strain energy functions, along with mass density terms to account for their quantitative presence in the tissue. Collagen fibre stretches are represented with a distribution function accounting for their existence in different stretches in the tissue. Scenarios are presented where the homoeostatic state of the collagen fibres adapt via evolution of the distribution function, which provide understanding on the configurations and mass changes that could be simulated to understand their implications on the structure and function of the tissue. It was observed that the model simulates plausible changes in the tissue function when collagen fibres are configured in the load bearing configuration rather than in the crimped form. A soft tissue growth and remodelling framework (STGRF) developed in Python, around the finite element simulation package (ANSYS ® Mechanical APDL) provides us with tools to develop biomechanical problems pertaining to the built-in fibre-reinforced, hyperelastic, incompressible soft tissue material model; employing stress-based differential equations for simulating tissue remodelling and growth. A key feature is the abstraction of the underlying coding using high level Python scripts, to ease the end-user into focussing on their research problem rather than be encumbered by programming ideologies. The STGRF, sees it’s applications in two distinct problems in this thesis. (A) An idealised LV subjected to myocardial infarction, using stressbased formulations to simulate tissue extra-cellular matrix adaptation to the progression of the disease. A fibroblast field, mediated by the collagen fibre stretches is introduced to regulate growth/ atrophy of the collagen mass density in the myocardium. Two cases are explored to understand the impact of evolving homoeostatic Cauchy stresses for each volume element, versus, a constant homoeostatic Cauchy stress state which the tissue attempts to maintain throughout the time period of the disease. Lower dilatations in the wall structure and lower mass deposition is observed when evolving the homoeostatic stress. (B) A finite element model of the medial gastrocnemiusmuscle subjected to sustained overstretch is considered and remodelling of the muscle and tendinous regions is observed. The novelty lies in the definition of themuscle, tendon and aponeurosis regions, reflected in the material parameter ascription to said regions. Using stress-based differential equations, remodelling of the muscle and tendinous regions are observed with varying rate constants. The model is purely exploratory in terms of remodelling of the distinct regions in the gastrocnemius muscle and future sophistications could aid in better understanding rehabilitation therapies, surgical techniques involved in muscle extension or purely adaptation to a variety of external mechanical stimuli and environments. Mathematical and computational modelling enables us replicate models based on specific elements in disease which are difficult to capture experimentally or clinically. This sheds light on the possiblemechanisms in play and delineate the processes in order to better understand the changes in tissue structure and function

Stereoisomer libraries: Total synthesis of all 16 stereoisomers of the pine sawfly sex pheromone by a fluorous mixture-synthesis approach

All 16 stereoisomers of the sex pheromone of pine sawfly (3,7,11-trimethylundecanol propanoate ester) have been synthesized on a 10- to 20-mg scale by a split-parallel fluorous mixture-synthesis approach. Spectral data obtained for all 32 compounds (16 alcohols and the corresponding propionates) matched well with published data, thereby validating the fluorous-tag encoding of diastereoisomers. This fluorous-tag encoding method is recommended for the efficient synthesis of multiple stereoisomers for spectroscopic studies, biological tests, or other structure-function relationships

MERCURY POISONING AND MANAGEMENT: A SYSTEMATIC REVIEW

ABSTRACTA great number of literatures have been documented the destructive effects of the heavy metal toxin on the brain, kidneys, and nervous systems.Mercury is one of such chemicals of the environmental toxin which produces adverse effects causing mercury poisoning a leads to accumulation in thetissues of the body. Mercury occurs in various forms even though they are interchangeable which is the deadly feature of this chemical which is thecause for this mercury poisoning. That is, there are three types, namely, elemental, organic, and inorganic mercury. So, mercury has different effectsin the body according to its chemical forms. Exposure to this chemical occurs in two ways through environmental exposure or due to occupationalexposure. Different forms of mercury target different vital organs of the body, on failure of these organs are crucial for the body which might lead tothe death of the individual. Diagnosis of different types of mercury poisoning can be done by analyzing the samples of hair, urine, whole blood, andcertain tissues of the body. This analysis also gives us the results of recent exposure to the chemical. According to the lab diagnostic report and throughpreliminary clinic examination, the patient is treated according to the duration and dosage of mercury exposed to.Keywords: Mercury poisoning, Environmental toxin, Mercury, Occupational hazards

Microbial production of 1-octanol: a naturally excreted biofuel with diesel-like properties

The development of sustainable, bio-based technologies to convert solar energy and carbon dioxide into fuels is a grand challenge. A core part of this challenge is to produce a fuel that is compatible with the existing transportation infrastructure. This task is further compounded by the commercial desire to separate the fuel from the biotechnological host. Based on its fuel characteristics, 1-octanol was identified as an attractive metabolic target with diesel-like properties. We therefore engineered a synthetic pathway specifically for the biosynthesis of 1-octanol in Escherichia coli BL21(DE3) by over-expression of three enzymes (thioesterase, carboxylic acid reductase and aldehyde reductase) and one maturation factor (phosphopantetheinyl transferase). Induction of this pathway in a shake flask resulted in 4.4 mg 1-octanol L(-1) h(-1) which exceeded the productivity of previously engineered strains. Furthermore, the majority (73%) of the fatty alcohol was localised within the media without the addition of detergent or solvent overlay. The deletion of acrA reduced the production and excretion of 1-octanol by 3-fold relative to the wild-type, suggesting that the AcrAB-TolC complex may be responsible for the majority of product efflux. This study presents 1-octanol as a potential fuel target that can be synthesised and naturally accumulated within the media using engineered microbes

AMP-Activated Protein Kinase:Friend or Foe in Cancer

The AMP-activated protein kinase (AMPK) is activated by energy stress and restores homeostasis by switching on catabolism, while switching off cell growth and proliferation. Findings that AMPK acts downstream of the tumor suppressor LKB1 have suggested that AMPK might also suppress tu-morigenesis. In mouse models of B and T cell lymphoma in which genetic loss of AMPK occurred before tumor initiation, tumorigenesis was accelerated , confirming that AMPK has tumor-suppressor functions. However, when loss of AMPK in a T cell lymphoma model occurred after tumor initiation , or simultaneously with tumor initiation in a lung cancer model, the disease was ameliorated. Thus, once tumorigenesis has occurred, AMPK switches from tumor suppression to tumor promotion. Analysis of alterations in AMPK genes in human cancers suggests similar dichotomies, with some genes being frequently amplified while others are mutated. Overall, while AMPK-activating drugs might be effective in preventing cancer, in some cases AMPK inhibitors might be required to treat it