Annotated check-list of plants occuring in lake Manyara National Park

Volume: 2

Electrochemical immunoassay for the detection of stress biomarkers

A rapid electrochemical immunoassay method was developed to detect and measure stress biomarkers (cortisol and cortisone) in two biological samples (Zebrafish whole-body and artificial saliva). This methodology utilizes an immunoassay approach taking advantage of the lock and key mechanism that is related to the antibody-antigen interaction depending on the reliable immobilization of the antibody labelled with ferrocene tags (Ab-Fc) on a modified tin-doped indium oxide (ITO) electrode using electrochemical instrumentation to build a POC platform. The limit of detection (LOD) obtained for this biosensor was 1.03 pg ml−1 for cortisol and 0.68 pg ml−1 for cortisone, respectively. The correlation coefficient was 0.9852 and 0.9841 for cortisol and cortisone, respectively with a linear concentration from (0-50 ng ml−1) which covers the standard levels of stress hormones in both selected biological samples. The incubation time was investigated and 30 min was found to be the optimum incubation time. This time would be acceptable for the POC system as total process time can be determined within 35 min

Interaction of temperature, salinity and extracellular polymeric substances controls trace element incorporation into tufa calcite

The influence of extracellular polymeric substances on carbonate mineral growth in natural settings remains one of the most poorly understood contributors to the growth of non-marine carbonate sediments. The influences of these materials are complicated by their association with living cells creating local microenvironments via metabolism and enzyme production, and by our uncertainty about the extracellular polymeric substances materials themselves. Different mixtures of extracellular polymeric substance molecules may behave in different ways, and differences in the local physical environment may alter how the mixtures influence mineral formation, and even result in different patterns of polymerization. Here, the influence of extracellular polymeric substances on calcite precipitation rate and Mg/Cacalcite in the absence of cells is investigated using extracts of extracellular polymeric substances from temperate fluvial tufa biofilm. The influence is complex, with the concentration of extracellular polymeric substances in solution altering deposition rate and trace element incorporation. Moreover, the results show interaction of the presence/absence of extracellular polymeric substances and both temperature and salinity. However, despite extracting extracellular polymeric substances from the same parent sample, a uniform influence was not found in these experiments, implying that the mixture is sufficiently variable within a sample for microenvironments within the biofilm to either promote or inhibit mineralization. As sedimentologists, we can no longer take the view that extracellular polymeric substances are a bystander material, or that they have a single set of coherent and predictable or intuitive influences. Rather, the emphasis must be on investigating the specific mixtures present in nature, and their complex and dynamic interaction with both mineral surfaces and hydrochemical conditions

Reduction of Energetic Demands through Modification of Body Size and Routine Metabolic Rates in Extremophile Fish

Citation: Passow, C. N., Greenway, R., Arias-Rodriguez, L., Jeyasingh, P. D., & Tobler, M. (2015). Reduction of Energetic Demands through Modification of Body Size and Routine Metabolic Rates in Extremophile Fish. Physiological and Biochemical Zoology, 88(4), 371-383. doi:10.1086/681053Variation in energy availability or maintenance costs in extreme environments can exert selection for efficient energy use, and reductions in organismal energy demand can be achieved in two ways: reducing body mass or metabolic suppression. Whether long-term exposure to extreme environmental conditions drives adaptive shifts in body mass or metabolic rates remains an open question. We studied body size variation and variation in routine metabolic rates in locally adapted populations of extremophile fish (Poecilia mexicana) living in toxic, hydrogen sulfide-rich springs and caves. We quantified size distributions and routine metabolic rates in wild-caught individuals from four habitat types. Compared with ancestral populations in nonsulfidic surface habitats, extremophile populations were characterized by significant reductions in body size. Despite elevated metabolic rates in cave fish, the body size reduction precipitated in significantly reduced energy demands in all extremophile populations. Laboratory experiments on common garden-raised fish indicated that elevated routine metabolic rates in cave fish likely have a genetic basis. The results of this study indicate that adaptation to extreme environments directly impacts energy metabolism, with fish living in cave and sulfide spring environments expending less energy overall during routine metabolism

Abnormalities in circadian blood pressure variability and endothelial function: pragmatic markers for adverse cardiometabolic profiles in asymptomatic obese adults

BACKGROUND: Cardiovascular disease (CVD) risk, although perceived to be high, is often difficult to demonstrate in disease free (healthy) obese adults. HYPOTHESIS: Changes in circadian blood pressure variability (CBPV) and endothelial function (EF) may be early correlates of cardiometabolic disorders. METHODS: Asymptomatic men and women in 3 groups: normal weight (n = 10), overweight (n = 10) and obese (n = 15) were evaluated. Blood pressure and heart rate were recorded over 7 days: every 30 minutes during the day and every 60 minutes during the night, by automatic ambulatory monitoring. Resting EF was assessed in a fasting state between 8-10 AM by brachial ultrasound. Anthropometric and cardiometabolic indicators were measured and correlations with CBPV and EF were investigated. RESULTS: The 3 groups had (Mean(SD)) BMI: 22.6(1.6), 27(3) and 34(5) kg/m(2), respectively, weight: 64(16), 79(14), 95(16) kg and waist circumference: 79(9), 93(10), 107(13) cm. None in normal-weight or overweight groups had abnormal CBPV, while 8 of 15 obese adults had one or more CBPV abnormities (p < 0.05). Obese adults with CBPV abnormalities had elevated hs-CRP (15.3(9.3) mg/L), fibrinogen (593(97) mg/dl), fasting serum glucose (102(16) mg/dL), and cardiac risk ratios (Total-C/HDL-C: 5.2(1.9), LDL-C/HDL-C: 3.1(1.4)). Adults in the 3 respective groups who did not have CBPV abnormalities had flow-mediated brachial artery dilatation (FMD) of 0.22(0.06); 0.20(0.04), 0.23(0.02) mm over resting diameter. Obese participants with CBPV abnormalities (Mesor-hypotension, circadian hyper amplitude tension, elevated pulse pressure), had attenuated FMD at 78, 52, and 56% of resting reference diameter (means 0.18(0.07), 0.12(0.08), and 0.13(0.05) mm; p < 0.05), respectively. CONCLUSIONS: Asymptomatic obese adults with abnormal CBPV and EF exhibit unfavorable cardiometabolic profiles

New professionals in formation: how do student teachers conceptualize their own learning?

We examine how beginning teachers in the UK conceptualise their own learning to teach, using the 'Conceptual Change' approach (Vosniadou, 2013). Our sample of 37 from three university centres includes primary and secondary beginning teachers on undergraduate and postgraduate routes, and a new school-based route into teaching ('School Direct'). We conducted interviews in the middle and at the end of their teacher education programmes. We identified six dimensions within beginning teachers conceptions of learning to teach. Our analysis indicates that a high degree of self-determination was associated with reflection on ‘being a teacher’ and a view of knowledge for teaching as uncertain. Many student teachers did not appear to change their conception at all and others regressed from a more complex conception of learning to teach to being recipients of 'good ideas'. Those who experienced co-construction seemed to be more open to conceptualizing learning to teach as complex. This matters for teacher educators who, we believe, should pay careful attention to what they are encouraging student teachers to focus on in their reflection and should aim to create conditions for learning in which student teachers experience co-construction

A new liver perfusion and preservation system for transplantation Research in large animals

A kidney perfusion machine, model MOX-100 (Waters Instruments, Ltd, Rochester, MN) was modified to allow continuous perfusion of the portal vein and pulsatile perfusion of the hepatic artery of the liver. Additional apparatus consists of a cooling system, a membrane oxygenator, a filter for foreign bodies, and bubble traps. This system not only allows hypothermic perfusion preservation of the liver graft, but furthermore enables investigation of ex vivo simulation of various circulatory circumstances in which physiological perfusion of the liver is studied. We have used this system to evaluate the viability of liver allografts preserved by cold storage. The liver was placed on the perfusion system and perfused with blood with a hematocrit of approximately 20% and maintained at 37°C for 3 h. The flows of the hepatic artery and portal vein were adjusted to 0.33 mL and 0.67 mL/g of liver tissue, respectively. Parameters of viability consisted of hourly bile output, oxygen consumption, liver enzymes, electrolytes, vascular resistance, and liver histology. This method of liver assessment in large animals will allow the objective evaluation of organ viability for transplantation and thereby improve the outcome of organ transplantation. Furthermore, this pump enables investigation into the pathophysiology of liver ischemia and preservation. © 1990 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted