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Conventional ultrasonographic examination of the bovine ovary is based on a sequence of two-dimensional (2D) cross-section images. Day-to-day estimation of the number, size, shape and position of the ovarian follicles is one of the most important aspects of ovarian research. Computer-assisted follicle segmentation of ovarian volume can relieve physicians from the tedious manual detection of follicles, provide objective assessment of spatial relationships between the ovarian structures and therefore has the potential to improve accuracy. Modern segmentation procedures are performed on 2D images and the three-dimensional (3D) visualization of follicles is obtained from the reconstruction of a sequence of 2D segmented follicles. <p>The objective of this study was to develop a semi-automatic 3D follicle segmentation method based on seeded region growing. The 3D datasets were acquired from a sequence of 2D ultrasound images and the ovarian structures were segmented from the reconstructed ovarian volume in a single step. A seed is placed manually in each follicle and the growth of the seed is controlled by the algorithm using a combination of average grey-level, standard deviation of the intensity, newly-developed volumetric comparison test and a termination criterion. One important contribution of this algorithm is that it overcomes the boundary leakage problem of follicles of conventional 2D segmentation procedures. The results were validated against the aspiration volume of follicles, the manually detected follicles by an expert and an existing algorithm.<p>We anticipate that this algorithm will enhance follicular assessment based on current ultrasound techniques in cases when large numbers of follicles (e.g. ovarian superstimulation) obviate accurate counting and size measurement.

Pentachlorophenol (PCP) is a priority environmental pollutant in North America that was widely used as a wide-spectrum biocide in the last century. Pentachlorophenol 4-monooxygenase (PcpB) is the first and rate-limiting enzyme in the PCP biodegradation pathway in <i>Sphingobium chlorophenolicum</i> ATCC 39723.<p> Pentachlorophenol 4-monooxygenase (PcpB) catalyzes the hydroxylation of pentachlorophenol in the pentachlorophenol biodegradation pathway in Sphingobium chlorophenolicum. Previous studies from two different research groups proposed oppositely that the catalytic product of PcpB was tetrachlorohydroquinone (TCHQ) and tetrachlorobenzoquinone (TCBQ). We re-examined the identity of the catalytic product of PcpB, because TCHQ and TCBQ are present in a redox-equilibrium in aqueous solutions and the chemical reagents NADPH, ethyl acetate and glutathione used for the product detection in the previous studies may shift the redox-equilibrium. In this study, we investigated the effects of NADPH, ethyl acetate and glutathione on the redox-equilibrium and product distribution. Under newly designed experimental conditions, we confirmed unambiguously that the catalytic product of PcpB is TCHQ instead of TCBQ. We also propose that TCBQ may be produced non-specifically by peroxidases within the bacterial cells and that TCBQ reductase (PcpD) might act as a self-protective rather than a PCP-degradation enzyme. <p> There is no glutathione S-transferase (GST) activity for wild type of PcpC, PcpC (C13S) mutant and a surface loop deletion mutant PcpC (LD). In the crystallization studies, PcpC (C13S), PcpB and PcpA were over-expressed and purified to >95% purity using Ni-NTA based affinity chromatography. Initial crystallization conditions have been obtained for all three enzymes from both in-house screening using the screening kits from Qiagen-Nextal and high throughput screening at the Hauptman-Woodward Institute, Buffalo, New York. Further structural determination studies will be undertaken upon obtaining large crystals suitable for X-ray diffraction data collection.

Thesis--Auburn University, 2009. / Abstract. Includes bibliographic references.

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