Cholecystokinin and the ontogeny of digestion in the red drum (Sciaenops ocellatus)

textWhile substantial progress has been made in replacing live prey with artificial diets in the feeding of marine fish larvae, it still remains impossible to successfully rear larvae on artificial diets without some period of co-feeding live prey or algae. This study investigated the presence and role of the gastrointestinal hormone cholecystokinin (CCK) in the red drum (Sciaenops ocellatus) to gain a better understanding of the factors limiting the utilization of artificial diets by red drum larvae. Work with other fish species has shown that CCK is the principal hormone which regulates the release of pancreatic enzymes into the gut lumen and emphasizes the potential importance of CCK in early red drum larvae. This work investigated the hypothesis that some signal present in the live prey or algae stimulates CCK and thereby initiates the digestive process in the larvae. First, the nucleotide and amino acid sequence of the putative red drum cholecystokinin precursor was determined and the development of CCK immunoreactive cells was examined. This work showed that red drum CCK is highly similar to CCK in other vertebrates and can be detected in the digestive tract of larval red drum within three days after the initiation of exogenous feeding. Next; postprandial trypsin, CCK, and CCK mRNA responses were quantified in red drum juveniles and larvae over a three hour period. Both CCK and trypsin were increased within thirty minutes following feeding while CCK mRNA levels were increased within the next two to three hours. Finally, the trypsin, CCK, and CCK mRNA responses of red drum larvae to homogenates of live prey and algae were examined. Homogenized rotifers appeared to be sufficient to induce both the CCK and trypsin responses in larval red drum. These results suggest that in addition to other factors, some component of live prey may initiate the release of CCK and prime the digestive process. Understanding these factors and their effects in early larvae may allow us to formulate and produce a prepared diet which will support growth and survival to metamorphosis equal to that provided by live feeds.Marine Scienc

Regulation of branched-chain amino acid metabolism in major metabolic tissues of dairy cows during late pregnancy and early lactation

For dairy cows, the transition from late pregnancy to early lactation is characterized by dramatic changes in endocrine status, nutrient utilization as well as tissue metabolism. Specific metabolic processes, e.g., in adipose tissue (AT) thereby contribute to the physiological adaptation to the increased nutrient demands imposed by the onset of lactation. Even though AT is known to be a major site for regulating glucose and lipid metabolism, its role in systemic protein and amino acid metabolism in dairy cows is not clear. The branched-chain amino acids (BCAA) are taken up by the mammary gland in excess and are greatly used for the synthesis of (milk) protein as well as the supply of metabolic intermediates and energy. Their cellular transport and break-down are highly regulated key processes, involving the interaction of several metabolic tissues, one of them possibly AT. Yet, studies on the BCAA transporters or degrading enzymes in ruminant tissues are sparse. Thus, one aim of the present thesis was to characterize the potential capacity of bovine AT (along with liver, skeletal muscle and mammary gland) for BCAA metabolism during late gestation and early lactation by analyzing the tissue abundance (and activity) of the most relevant BCAA transporters and catabolic enzymes as well as the concentration of circulating BCAA on selected time points before and after parturition. Moreover, as high BCAA levels have been linked with obesity and certain metabolic dysfunctions such as impaired insulin sensitivity in mammals, we further aimed to investigate the effect of over-conditioning at calving on the aforementioned variables of BCAA metabolism. Overall, AT consistently had the greatest mRNA abundance of the BCAA transporters and the BCAA transaminating enzyme, branched-chain aminotransferase 2 (BCAT2) when compared to most other tissues, but expressed a rather low oxidative capacity for BCAA (more specifically their keto acids), indicating that AT could be an important site of BCAA uptake and initial degradation in dairy cows. Together with the marginal hepatic mRNA abundance of BCAA transporters and BCAT2 and the high mRNA and protein abundance as well as activity of the subsequent oxidative enzyme in liver, the branched-chain α-keto acid dehydrogenase, it seems that BCAA are only degraded in the liver after being deaminated in peripheral tissues, most likely AT. Furthermore, we detected a decrease in circulating BCAA levels around parturition in our studies, which was associated with the reduced feed intake during this time. Both observations were more pronounced for cows that were over-conditioned at calving. Interestingly, despite the lower feed intake, those cows appeared to have a greater ability than normal-conditioned cows to irreversibly catabolize BCAA in AT, especially before parturition. It is likely that, due to a nutrient oversupply, the over-conditioned cows were in a more anabolic situation during late pregnancy and might have used BCAA metabolites in addition to glycolytic metabolites for synthesizing even more body fat. The present thesis thus provides information about a possible anaplerotic link between BCAA and lipid metabolism in AT of over-conditioned dairy cows and might serve as basis for further studies investigating the role of AT in systemic protein and AA metabolism in cattle during different physiological and pathophysiological conditions.Der Übergang von der späten Trächtigkeit zur frühen Laktation ist bei Milchkühen mit drastischen Veränderungen des endokrinen Status, der Nährstoffverwertung sowie des Gewebestoffwechsels verbunden. Spezielle Stoffwechselprozesse, beispielsweise im Fettgewebe (AT), tragen dabei zur physiologischen Anpassung an den durch die einsetzende Laktation erhöhten Nährstoffbedarf bei. Obwohl die regulativen Funktionen des AT im Glukose- und Lipidstoffwechsel bereits bekannt sind, weiß man bisher wenig über dessen Rolle im systemischen Protein- und Aminosäurestoffwechsel bei Milchkühen. Die verzweigtkettigen Aminosäuren (branched-chain amino acids, BCAA) werden im Übermaß von der Milchdrüse aufgenommen und dort verstärkt für die Synthese von (Milch-) Protein sowie für die Zufuhr von Stoffwechselintermediaten und Energie verwendet. Der zelluläre Transport und der Abbau der BCAA sind intensiv regulierte Kernprozesse, welche die Interaktion verschiedener metabolischer Gewebe, darunter möglicherweise auch AT, erfordern. Bislang gibt es jedoch nur wenige Studien, in welchen die BCAA-Transporter oder die BCAA-abbauenden Enzyme auf Gewebeebene bei Wiederkäuern untersucht worden sind. Demzufolge war ein Ziel dieser Arbeit die potenzielle Kapazität von bovinem AT (neben Leber, Skelettmuskulatur und Euter) für den BCAA-Stoffwechsel während der späten Trächtigkeit und frühen Laktation zu charakterisieren. Dies erfolgte durch Analyse der Gewebeexpression (und -aktivität) der relevantesten BCAA-Transporter und katabolen Enzyme sowie durch Messung der BCAA-Konzentration in der Zirkulation an ausgewählten Zeitpunkten vor sowie nach der Kalbung. Ferner, da erhöhte BCAA-Konzentrationen in Verbindung mit Übergewicht und gewissen metabolischen Dysfunktionen wie beispielsweise einer verschlechterten Insulinsensitivität bei Säugetieren stehen könnten, war es ein weiteres Ziel, den Einfluss von Überkonditionierung zum Zeitpunkt der Kalbung auf die zuvor genannten Parameter des BCAA-Stoffwechsels zu untersuchen. Fettgewebe wies generell die höchste mRNA-Expression der BCAA-Transporter und des BCAA-transaminierenden Enzyms branched-chain aminotransferase 2 (BCAT2) im Vergleich zu den meisten anderen Geweben auf, jedoch zeigte es eine recht geringe oxidative Kapazität für die BCAA (genauer deren Ketosäuren). Dies deutet darauf hin, dass AT von großer Bedeutung für die Aufnahme und den initialen Abbau von BCAA bei Milchkühen sein könnte. Zusammen mit der geringen hepatischen mRNA-Expression der BCAA-Transporter und der BCAT2 sowie der erhöhten mRNA- und Proteinexpression und Aktivität des nachfolgenden oxidativen Enzyms, der branched-chain α-keto acid dehydrogenase, in der Leber, weist dies darauf hin, dass BCAA nur in der Leber abgebaut werden können nachdem sie in peripheren Geweben, höchstwahrscheinlich dem AT, deaminiert wurden. Des Weiteren wurde in den dargestellten Studien eine Verringerung der BCAA-Konzentrationen zum Zeitpunkt der Kalbung festgestellt, welche mit der zeitgleich reduzierten Futteraufnahme assoziiert wurde. Diese Beobachtungen waren bei Kühen, welche zum Zeitpunkt der Kalbung überkonditioniert waren, deutlicher ausgeprägt. Interessanterweise schienen diese Tiere, trotz der geringeren Futteraufnahme, ein höheres Vermögen zu besitzen, BCAA irreversibel im AT zu katabolisieren als normalkonditionierte Kühe. Dies traf insbesondere für die Zeit vor der Kalbung zu. Es ist denkbar, dass sich die überkonditionierten Kühe während der späten Trächtigkeit, aufgrund eines Nährstoffüberangebots, in einer mehr anabolen Stoffwechselsituation befanden und demnach zusätzlich zu glykolytischen Stoffwechselprodukten ebenfalls BCAA-Metabolite für den Aufbau von weiterem AT nutzen konnten. Die vorliegenden Ergebnisse zeigen somit eine mögliche anaplerotische Verbindung zwischen BCAA- und Lipidstoffwechsel im AT überkonditionierter Milchkühe auf. Folglich dient diese Arbeit als essentielle Grundlage weiterer Untersuchungen, um die Funktionen des AT im systemischen Protein- und Aminosäurestoffwechsel bei Kühen in verschiedenen physiologischen und pathophysiologischen Stadien zu erforschen

Phenomenology as a methodology for Scholarship of Teaching and Learning research

The Scholarship of Teaching and Learning (SoTL) is a rich forum where scholars from different fields and philosophical orientations find space to share their research on teaching and learning in higher education. Within this paper, we will share our individual and collective experiences of why we perceive phenomenology as a methodology well-suited for a broad range of SoTL purposes. Phenomenology is a research approach that focuses on describing the common meaning of the lived experience of several individuals about a particular phenomenon. We will discuss how phenomenology informed our own SoTL research projects, exploring the experiences of faculty and undergraduates in higher education. We will highlight the challenges and affordances that emerged from our use of this methodology. Phenomenology has motivated us to tell our stories of SoTL research and within those, to share the stories that faculty and students shared

Soil governance in the agricultural landscapes of New South Wales, Australia

Soil is a valuable natural resource. In the state of New South Wales, Australia, the governance of soil has evolved since Federation in 1901. Following rapid agricultural development, and in the face of widespread soil degradation, the establishment of the Soil Conservation Service marked a turning point in the management of soil. Throughout the 20th century, advances in knowledge were translated into evolving governance frameworks that were largely reactionary but saw progressive reforms such as water pollution legislation and case studies of catchment-scale land and vegetation management. In the 21st century, significant reforms have embedded sustainable use of agricultural soils within catchment- and landscape-scale legislative and institutional frameworks. What is clear, however, is that a multitude of governance strategies and models are utilised in NSW. No single governance model is applicable to all situations because it is necessary to combine elements of several different mechanisms or instruments to achieve the most desired outcomes. Where an industry, such as the sugar industry, has taken ownership of an issue such as acid sulfate soil management, self-regulation has proven to be extremely effective. In the case of co-managing agricultural soils with other landuses, such as mining, petroleum exploration and urban development, regulation, compliance and enforcement mechanisms have been preferred. Institutional arrangements in the form of independent commissioners have also played a role. At the landscape or total catchment level, it is clear that a mix of mechanisms is required. Fundamental, however, to the successful evolution of soil governance is strategic investment in soil research and development that informs the ongoing productive use of agricultural landscapes while preventing land degradation or adverse environmental effects

The first high-amplitude delta Scuti star in an eclipsing binary system

We report the discovery of the first high-amplitude delta Scuti star in an eclipsing binary, which we have designated UNSW-V-500. The system is an Algol-type semi-detached eclipsing binary of maximum brightness V = 12.52 mag. A best-fitting solution to the binary light curve and two radial velocity curves is derived using the Wilson-Devinney code. We identify a late A spectral type primary component of mass 1.49+/-0.02 M_sun and a late K spectral type secondary of mass 0.33+/-0.02 M_sun, with an inclination of 86.5+/-1.0 degrees, and a period of 5.3504751+/-0.0000006 d. A Fourier analysis of the residuals from this solution is performed using PERIOD04 to investigate the delta Scuti pulsations. We detect a single pulsation frequency of f_1 = 13.621+/-0.015 c/d, and it appears this is the first overtone radial mode frequency. This system provides the first opportunity to measure the dynamical mass for a star of this variable type; previously, masses have been derived from stellar evolution and pulsation models.Comment: 7 pages, 6 figures, 2 tables, for submission to MNRAS, v2: paper size change, small typographical changes to abstrac

Effectiveness of TED Stockings on Circulation and Blood Clotting

Circulatory issues can stem from many disease that cause blood clots specifically in the legs, adding compression is known to help reduce blood clotting. The goal of this research project is to better understand the purpose and effectiveness of TED stocking on circulation and blood clotting and whether it is still an effective practice. The outcome of this research project is to improve our practice through the use of TED stockings for circulation and blood clotting

Feedback and Feed-Forward for Promoting Problem-Based Learning in Online Learning Environments

Purpose - The study aimed to (1) review the literature to construct conceptual models that could guide instructional designers in developing problem/project-based learning environments while applying effective feedback strategies, (2) use the models to design, develop, and implement an online graduate course, and (3) assess the efficiency of the models. Method - Quantitative and qualitative data were gathered during the implementation of an online graduate-level course that was designed and developed using the two proposed conceptual models. Eleven students were enrolled in the course. Multiple sources of data and analytical strategies were used to collect, analyze, and interpret the data. Findings - The results show that the characteristics and strategies suggested in the proposed models supported student achievement in course projects and activities. The timely and frequent feedback allowed students to make necessary changes to their final project parts and improve performance. The motivating, informative/ specific feedback and feed-forward goals appeared to provide a reference for areas of student improvement. A balance of the three types of feedback, along with metacognitive questioning, supported student improvement. Because the frequency of feedback was dependent upon student request, those who needed more frequent feedback during the acquisition of learning benefited from that, but those who did not need it received the moderate amount necessary to be successful. Significance - The study brings to light the importance of three types of formative feedback in problem or project-based learning. It offers two conceptual frameworks for instructional designers and curriculum developers. The models could be used to provide all forms of feedback including feed up, feedback and feed-forward to support student success in PBL learning environments

Phenomenology as a methodology for Scholarship of Teaching and Learning research

The Scholarship of Teaching and Learning (SoTL) is a rich forum where scholars from different fields and philosophical orientations find space to share their research on teaching and learning in higher education. Within this paper, we will share our individual and collective experiences of why we perceive phenomenology as a methodology well-suited for a broad range of SoTL purposes. Phenomenology is a research approach that focuses on describing the common meaning of the lived experience of several individuals about a particular phenomenon. We will discuss how phenomenology informed our own SoTL research projects, exploring the experiences of faculty and undergraduates in higher education. We will highlight the challenges and affordances that emerged from our use of this methodology. Phenomenology has motivated us to tell our stories of SoTL research and within those, to share the stories that faculty and students shared

The UNSW Extrasolar Planet Search: Methods and First Results from a Field Centred on NGC 6633

We report on the current status of the University of New South Wales Extrasolar Planet Search project, giving details of the methods we use to obtain millimagnitude precision photometry using the 0.5m Automated Patrol Telescope. We use a novel observing technique to optimally broaden the PSF and thus largely eliminate photometric noise due to intra-pixel sensitivity variations on the CCD. We have observed 8 crowded Galactic fields using this technique during 2003 and 2004. Our analysis of the first of these fields (centred on the open cluster NGC 6633) has yielded 49 variable stars and 4 shallow transit candidates. Follow-up observations of these candidates have identified them as eclipsing binary systems. We use a detailed simulation of our observations to estimate our sensitivity to short-period planets, and to select a new observing strategy to maximise the number of planets detected.Comment: 16 pages, 9 figures, version published in MNRAS Updated figures, references, and additional discussion in section