1,155 research outputs found

    Effects of Mutating CtrA-Binding Sites within the pile Promoter of Caulobacter Crescentus

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    This project investigated the regulation of pilA by the global transcriptional regulator CtrA in the dimorphic bacterium Caulobacter crescentus. The pilA gene encodes the pilin subunits which are polymerized into helical filaments to produce pili, and the gene is directly activated by CtrA such that filaments are produced after cell separation. The pilA promoter harbors three regions that have been shown to bind CtrA (Binding Regions 1, 2, and 3), and multiple CtrA recognition sites are found in these regions, which is unusual for CtrA-dependent promoters. However, none of the binding sites match the CtrA consensus binding sequence. The canonical CtrA recognition sequence most closely matches the DNA sequence of Binding Region 1, and it is at relative variance with the sequences of Binding Regions 2 and 3. To examine the role of different binding sites in pilA activation, different pilA-lacZ constructs bearing isolated or combined binding region sites within the pilA promoter were introduced to C. crescentus. Ligation reactions were implemented to join novel pilA promoter constructs with cleaved reporter vectors (plac290). Heat shock methods were used to transform Escherichia coli with putative pilA-lacZ constructs, and electroporation was used to clone pilA-lacZ vectors into C. crescentus cultures. Beta-galactosidase assays were implemented to measure the strength of the novel pilA promoters in transgenic C. crescentus cells. My results demonstrate that the CtrA binding region bearing the binding site that is closest to the consensus sequence (Binding Region 1) barely induces pilA expression, and the pairing of this region with Binding Region 2 (whose binding sites are far from consensus) augments pilA expression - by more than twenty-fold - to levels which are characteristic of wild type. In addition, my results reveal that (1) the absence of Binding Region 3 enacts no effect on the intensity of pilA expression and (2) Binding Region 2 alone is not sufficient to induce significant pilA expression. In conclusion, my research indicates that the orchestration of multiple binding regions is necessary for effective transcription of pilA

    Linking Land and Water Resource Management in Southern Thailand: Viewing Sustainable Resource Solutions Through a Double Lens

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    Global demands for water continue to rise while at the same time, the availability of reliable water resources are deteriorating. As 70% of the world’s human consumption of water resources is directed towards agricultural production, the need to improve water use efficiency and sustainability in these areas is of utmost importance. In order to tackle these issues, the concept of “Integrated water resource management” (IWRM) has been developed and is currently the most globally accepted and widely implemented strategy for attaining equitable, efficient and sustainable water management. Due to the extensive adoption of IWRM, the need to examine the successes and challenges of this strategy is warranted. This case study, which is set in an agricultural river basin in southern Thailand, will address the question of how government policies in Thailand encouraging palm oil production are influencing the ability of rural communities to effectively manage their water resources. While the Thai government has formally embraced IWRM, its effectiveness in coordinating land and water resource management in the nation across all levels of government is still in question. For many cases of IWRM, one of the most significant obstacles facing practitioners is that of developing full and effective stakeholder engagement. Although this term has been understood as a vital component for IWRM success, the disconnection between ‘ground-up’ local community resource management efforts and ‘top-down’ higher level governmental policies still persist. Through the analysis of this case using Institutional Theory and in particular, the “Institutional Analysis and Development (IAD) Framework”, the results of this study demonstrate that efforts to enhance stakeholder engagement could benefit from a deeper understanding of the local level institutional processes that are at the core of rurally based natural resource management strategies

    Local Protectionism and Regional Specialization: Evidence from China’s Industries

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    This paper uses a dynamic panel estimation method to investigate the determinants of regional specialization in China’s industries, paying particular attention to local protectionism. Less geographic concentration is found in industries where the past tax-plus-profit margins and the shares of state ownership are high, re- flecting stronger local government protection of these industries. The evidence also supports the scale-economies theory of regional specialization. Finally, the overall time trend of regional specialization of China’s industries is found to have reversed an early drop in the mid 1980s, and registered a significant increase in the later years.http://deepblue.lib.umich.edu/bitstream/2027.42/39951/3/wp565.pd

    Local Protectionism and Regional Specialization: Evidence from China’s Industries

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    This paper uses a dynamic panel estimation method to investigate the determinants of regional specialization in China’s industries, paying particular attention to local protectionism. Less geographic concentration is found in industries where the past tax-plus-profit margins and the shares of state ownership are high, re- flecting stronger local government protection of these industries. The evidence also supports the scale-economies theory of regional specialization. Finally, the overall time trend of regional specialization of China’s industries is found to have reversed an early drop in the mid 1980s, and registered a significant increase in the later years.local protectionism, regional specialization, scale economy, external economy.

    Differential expression of stem cell-like proteins in normal, hyperplastic and dysplastic oral epithelium

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    Objective The identification of stem cells (SC) remains challenging. In the human oral mucosal epithelium, these cells are believed to be in the basal layer (stem cell niche), but their exact location is unclear. The aim of this study was to examine the dysplastic oral epithelium for these SC-like proteins in order to assess their diagnostic value as biomarkers complementing the histological grading of dysplasia. Material and Methods Thirty oral epithelial dysplasia (OED), 25 oral lichen planus (OLP), 10 oral hyperkeratosis and 5 normal oral epithelium (OE) were immunohistochemically examined for four SC markers [integrin β1, neuron-glial-2 (NG2), notch 1 (N1) and keratin 15 (K15)]. Results Three of four SC markers were heterogeneously detected in all samples. K15 overexpression in the lower two-thirds of severe OED suggests an expanded SC niche. Integrin β1 distribution pattern was not measurably different between OEDs and control. NG2 was almost negative to absent in all samples examined. N1 expression was weak and highly variable in normal and dysplastic epithelium, making it an unreliable epithelial stem cell marker. Conclusions Present findings suggest that these markers were unable to identify individual epithelial stem cells. Instead, subpopulations of cells, most probably stem cells and transit amplifying cells with stem cell-like properties were identified in the dysplastic oral epithelium. The characteristic expressions of K15 might be of diagnostic value for oral dysplasia and should be investigated further

    The 5'-3' exoribonuclease pacman is required for epithelial sheet sealing in Drosophila and genetically interacts with the phosphatase puckered

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    Background information. Ribonucleases have been well studied in yeast and bacteria, but their biological significance to developmental processes in multicellular organisms is not well understood. However, there is increasing evidence that specific timed transcript degradation is critical for regulation of many cellular processes, including translational repression, nonsense-mediated decay and RNA interference. The Drosophila gene pacman is highly homologous to the major yeast exoribonuclease XRN1 and is the only known cytoplasmic 5′–3′ exoribonuclease in eukaryotes. To determine the effects of this exoribonuclease in development we have constructed a number of mutations in pacman by P-element excision and characterized the resulting phenotypes. Results. Mutations in pacman resulted in flies with a number of specific phenotypes, such as low viability, dull wings, crooked legs, failure of correct dorsal/thorax closure and defects in wound healing. The epithelial sheet movement involved in dorsal/thorax closure is a conserved morphogenetic process which is similar to that of hind-brain closure in vertebrates and wound healing in humans. As the JNK (c-Jun N-terminal kinase) signalling pathway is known to be involved in dorsal/thorax closure and wound healing, we tested whether pacman affects JNK signalling. Our experiments demonstrate that pacman genetically interacts with puckered, a phosphatase that negatively regulates the JNK signalling pathway. Conclusions. These results reveal that the 5′–3′ exoribonuclease pacman is required for a critical aspect of epithelial sheet sealing in Drosophila. Since these mutations result in specific phenotypes, our data suggest that the exoribonuclease Pacman targets a specific subset of mRNAs involved in this process. One of these targets could be a member of the JNK signalling pathway, although it is possible that a parallel pathway may instead be affected. The exoribonuclease pacman is highly conserved in all eukaryotes, therefore it is likely that it is involved in similar morphological processes, such as wound healing in human cells

    Antimicrobial activity of copper kaolinite and surfactant modified copper kaolinite against gram positive and gram negative bacteria

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    The aim of this research was to determine the antimicrobial activity of kaolinite modified with antimicrobial compounds against Gram positive and Gram negative bacteria. Copper kaolinite (Cu-kaolinite) was prepared by loading raw kaolinite with copper nitrate trihydrate (CuNO3) while surfactant modified Cu-kaolinite (SM-Cu-kaolinite) was prepared by adding cationic surfactants hexadecyltrimethyl ammonium (HDTMA) on Cu-Kaolinite. Samples was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyzer. The antimicrobial activity of the samples was tested against Gram negative bacteria (Escherichia coli ATCC 11229 and Pseudomonas aeruginosa ATCC 15442), and Gram positive bacteria (Staphylococcus aureus ATCC 6538 and Enterococcus faecalis ATCC 29212) through disc diffusion technique (DDT) and minimum inhibition concentration (MIC). The results showed that the antimicrobial activity of Cu-kaolinite increased after modified with HDTMA due to the synergistic effects of Cu ions and HDTMA molecules on the kaolinite. The antimicrobial activity for surfactant modified Cu-kaolinite was greater for Gram positive bacteria compared to Gram negative bacteria. In conclusion, the attachment of HDTMA on Cu-kaolinite contributed to the enhanced antimicrobial activity against wide spectrum of bacteria (Gram positive and Gram negative bacteria)

    An examination of the perceived impact of a continuing interprofessional education experience on opiate prescribing practices

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    Chronic pain is increasingly recognized as a public health problem. We assessed the effectiveness of a multi-modal, interprofessional educational approach aimed at empowering healthcare professionals to make deliberative changes, especially in opiate prescribing practices. Education activities included enduring webcasts, regional interprofessional roundtable events, and state-level conference presentations within targeted Kentucky and West Virginia regions of the United States. Over 1,000 participants accessed the various activities. For the live events, the largest groups reached included nurses (38.1%), nurse practitioners (31.2%), and physicians (22.1%). In addition to our reach, higher levels of educational effectiveness were measured, specifically, learner’s intentions to change practice patterns, confidence in meeting patient’s needs, and knowledge of pain management guidelines. The majority of the conference (58%) and roundtable (69%) participants stated they intend to make a practice change in one or more areas of chronic pain patient management in post-event evaluation. Differences in pre- and post-activity responses on the measures of confidence and knowledge, with additional comparison to a control population who were not in attendance, were analyzed using non-parametric tests of significance. While neither activity produced significant changes in confidence from pre-activity, participants were more confident post-activity than their control group peers. There were significant changes in knowledge for both live event and webcast participants. Impactful chronic pain continuing the education that emphasizes collaborative care is greatly needed; these results show that the approaches taken here can impact learner’s knowledge and confidence, and hold potential for creating change in how opioid prescribing is managed

    Surrogates for myocardial power and power efficiency in patients with aortic valve disease

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    We aimed to assess surrogate markers for left ventricular (LV) myocardial power and efficiency in patients with isolated aortic stenosis (AS) and combined stenosis/regurgitation (AS/AR). In AS (n = 59), AS/AR (n = 21) and controls (n = 14), surrogates for LV myocardial power and circulatory/external myocardial efficiency were obtained from cardiac MRI. Median surrogate LV myocardial power was increased in AS, 7.7 W/m2 (interquartile range 6.0-10.2; p = 0.010) and AS/AR, 10.8 W/m2 (8.9-13.4; p < 0.001) when compared to controls, 5.4 W/m2 (4.2-6.5), and was lower in AS than AS/AR (p < 0.001). Surrogate circulatory efficiency was decreased in AS, 8.6% (6.8-11.1; p < 0.001) and AS/AR, 5.4% (4.1-6.2; p < 0.001) when compared to controls, 11.8% (9.8-16.9). Surrogate external myocardial efficiency was higher in AS, 15.2% (11.9-18.6) than in AS/AR, 12.2% (10.1-14.2; p = 0.031) and was significantly lower compared to controls, 12.2% (10.7-18.1) in patients with reduced ejection fraction (EF), 9.8% (8.1-11.7; p = 0.025). In 16% of all cases, left ventricular mass/volume indices and EF were within normal ranges, wheras surrogate LV myocardial power was elevated and patients were symptomatic. Although influenced by pressure/volume load, the myocardium is additionally affected by remodelling processes. Surrogates for circulatory efficiency and LV myocardial power gradually reflect alterations in patients with AS and AS/AR, even when surrogate external myocardial efficiency, EF, mass and volume indices still remain compensated
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