Impacts of interactions with soil organisms on the metabolome of ragwort (Senecio jacobaea L.)

Plants need to defend themselves against their natural enemies without compromising their interactions with beneficial organisms. Chemical mechanisms underpin many of these interactions and changes in plant metabolism are critical to both robust defences against antagonists and effective signals to mutualists. Further, such plant responses can be systemic, so mediating interactions between spatially separated organisms above and below ground. This thesis aimed to characterise the changes in the ragwort (Senecio jacobaea L.) metabolome caused by two different belowground organisms, an antagonistic herbivorous nematode (Pratylenchus penetrans (Cobb, 1917) Filipjev & Schuurmans Stekhoven, 1941) and a mutualist arbuscular mycorrhizal fungus (AMF) (Glomus intraradices Smith & Schenck). Initially, vegetative and reproductive stage ragwort plants were sampled in the field and the chemical composition of leaf and flower tissues was assessed using a metabolomic approach. Techniques for the identification of key ragwort secondary metabolites were trialled and results demonstrated that plants of different ages differed in their allocation of within plant defences such as flavanoids, pyrrolizidine alkaloids (PAs) and chlorogenic acids. Subsequent experiments with nematodes and AMF focussed on the analysis of leaf tissues from vegetative stage plants. Feeding by the nematode species P. penetrans resulted in increased concentrations of metabolites associated with plant defence, including the main class of ragwort defence compounds PAs. In contrast, colonisation of root material by AMF caused increases in the concentrations of metabolites associated with the maintenance of the beneficial interaction between plant and fungi, such as a number of apocarotenoids known as blumenols. The findings of both experimental studies detected unexpected and previously unreported changes in plant metabolism, highlighting the importance of an untargeted approach when examining the chemical ecology of plant interactions

The regulation of human fetal gonadal development in the second trimester

Fetal gonadal development is a complex process dependent on maturation and differentiation of several cell types with different functions. Adequate development is important for normal sexual development and fertility potential. However, to date the factors that are involved in the regulation of gonadal growth and differentiation are not well understood. The aim ofthis thesis was to investigate the role of survival and proliferative factors, namely the c-kit proto-oncogene receptor and ligand and the family of neurotrophins in human gonadal development during mid-trimester. The involvement of metalloproteinases (MMPs) and their inhibitors (TIMPs) in tissue remodelling in both human fetal testes and ovaries was also considered. C-kit and its ligand have been demonstrated to be essential to the processes of germ cell migration, proliferation and survival in the rodent and their expression was investigated in human fetal gonads. Expression of c-kit mRNA and the protein was demonstrated in both ovary and testis throughout mid-trimester. Testicular germ cellspecific expression of c-kit mRNA was confirmed using laser capture microscopy and c-kit protein was localised to the germ cells in both ovaries and testes. These data demonstrate that the expression of c-kit mRNA and protein is germ cell specific in human fetal gonads and are consistent with an important role for the c-kit/kit ligand signalling system in germ cell proliferation and survival in the developing human gonad.Neurotrophins are survival and differentiation factors in the nervous system. The presence of neurotrophins and their receptors and their role in germ cell survival was investigated in the human fetal gonads. Expression and localisation of neurotrophins 7 and their receptors was detected throughout mid-trimester in both ovaries and testes. The effects of the tyrosine kinase receptor inhibitor K252a were studied in organ cultures. In the ovary, treatment with K252a resulted in a significant fall in germ cell number and proliferation. In the testis, cell-specific marked decrease in both gonocyte and peritubular cell number and proliferation was seen after treatment with K252a, with little effect on Sertoli cells. These findings therefore demonstrate the expression of neurotrophins and their receptors in human fetal gonads during the second trimester and indicate possible roles in the regulation of proliferation/survival of germ cells and peritubular cellsMMPs and TIMPs are major regulators of tissue remodelling of the extracellular matrix (ECM) and may also be involved in the control of growth factor availability. Their production and localisation was investigated in the human fetal gonad. Tissue was collected and analysed for the presence of MMP-2 and -9 and for TIMP activities using zymographic techniques. These MMPs and in addition, MMP-I and TIMPs were localised using immunohistochemistry. The secretion of MMP-2, -9 and all four TIMPs was demonstrated from both testis and ovary, the predominant gelatinase produced being MMP-2. In both gonads, MMP-I, -2, -9 and all TIMP family members were localised to specific cell types. This therefore indicates that MMPs and TIMPs are likely to play a role in ECM remodelling during fetal gonadal development and also in the cell and matrix interactions that control a range of cellular function

Sanctuaries

Sanctuaries navigates the environment of home via interrelated essays and vignettes personal to my upbringing in rural Southwest Indiana. By exploring my own childhood, youth, and family traumas and successes, I have crafted a collection that speaks volumes about seeing the world from a perspective both privileged and underprivileged simultaneously. I uncover my lineage\u27s numerous bouts with physical and mental illness and unrealized dreams, but I also bring to light our traditions of spreading kindness, treading lightly in the world, and preparing inordinate amounts of food and festive cheer to balance out times of hardship. Few writers have attempted to paint the Southern-Midwest\u27s landscape and to characterize its people as more than caricatures caught between the factories of the north and the tobacco fields of the south, so I rose to that challenge. What results is an essay collection rife with excess and squalor, abandon and abandonment, humor and deep sorrow, atheism and fervent belief in the supernatural, and snippets of what it really means, by my home region\u27s estimation, to be part of a family

Evaluation of an automated ankle brachial pressure index calculator in a nurse-led leg ulcer clinic

The Dopplex Ability® is a new automated ankle brachial pressure index (ABPI) calculator, the increased use of which the authors are witnessing in clinical practice. Proposed benefits over the traditional hand-held Doppler machine and manual blood pressure (BP) sphygmomanometer include: ease of use, reduced procedure time and reduced time lying flat for patient, which may lead to more cost- effective treatment outcomes. Since it is routine practice in a number of clinical areas for two members of staff to carry out the holistic leg ulcer assessment process, an additional benefit may be the ability of a single member of staff with minimum training to use the Dopplex Ability. An evaluation of the Dopplex Ability was carried out at a busy nurse-led community leg ulcer clinic over a period of 3 months. A total of 22 patients who attended the clinic for Doppler assessment consented to participate. Participants underwent ABPI calculation using both the Dopplex Ability and the hand-held Doppler. Overall 56% of readings were marginally higher with the Dopplex Ability than with the hand-held Doppler; 9% of readings were lower and 34% were equal. ABPI readings from the Dopplex Ability equipment were on average 0.067 higher than corresponding readings taken from hand-held equipment; this difference was statistically significant (p=0.014). Differences between methods were greater in patients who had readings taken by the Dopplex Ability first than in patients who had hand-held readings taken first. The majority of patients found the Dopplex Ability to be tolerable and staff found it easy to use. The Dopplex Ability was found to be a useful adjuvant to the hand-held Doppler

Expression, Purification, Crystallization and Preliminary X-Ray Analysis of \u3cem\u3ePseudomonas aeuginosa\u3c/em\u3e AlgX

AlgX is a periplasmic protein required for the production of the exopolysaccharide alginate in Pseudomonas sp. and Azotobacter vinelandii. AlgX has been overexpressed and purified and diffraction-quality crystals have been grown using iterative seeding and the hanging-drop vapor-diffusion method. The crystals grew as flat plates with unit-cell parameters a=46.4, b=120.6, c=86.9Å, β=95.7°. The cyrstals exhibited the symmetry of space group P21 and diffracted to a minimimum d-spacing of 2.1Å. On the basis of the Matthews coefficient (VM=2.25Å3 Da-1), two molecules were estimated to be present in the asymmetric unit

Targeting of ricin A chain into pea chloroplasts

AbstractAchimaeric gene was constructed encoding the pre-sequence of the 33 kDa oxygen-evolving complex protein from wheat (a thylakoid lumen protein) linked to ricin A chain. The fusion protein is efficiently imported by isolated pea chloroplasts and localised partly in the stroma, with the remainder bound to the stromal surface of the thylakoids. The imported protein is fully processed by both the stromal and thylakoidal processing peptidases, indicating that partial or complete translocation across the thylakoid membrane has taken place