Influences of Drosophila circadian clock on sugar-mediated physiological changes

It is widely known that high sugar consumption and poor sleep are detrimental to human health. Both are risk factors for obesity, which can lead to conditions such as heart disease. Despite this connection between sugar and sleep, little is known about how circadian clock dysfunction affects the physiological changes caused by increased sugar consumption. In this thesis, a mutant line of the model organism Drosophila melanogaster (ClkJrk, which contains a nonfunctional circadian rhythm gene known as Clk) that leads to circadian dysfunction, was exposed to a high sugar diet to observe how Clk affects sugar-related changes to food consumption, sleep, triglyceride levels, and starvation resistance. Despite previous research suggesting that the circadian rhythm affects feeding, ClkJrk flies did not substantially differ from wild-type flies in terms of food consumption. In addition, both ClkJrk and wild-type flies slept less on low-sugar food. However, unlike wild-type flies, ClkJrk flies did not experience increased starvation resistance on a high sugar diet, suggesting that a functioning Clk gene is essential for flies fed a high sugar diet to survive when starved. Lowered triglyceride levels in ClkJrk flies may explain the reduced starvation resistance of ClkJrk flies fed high sugar diets. The findings from this research provide a greater understanding of how sleep and sugar intertwine to affect health and disease. Future studies should explore the endocrine components of this relationship in Drosophila, particularly the Drosophila Insulin-Like Peptides (DILPs), which regulate nutrient storage and release

The Motion Aftereffect: Mechanisms and Variants

The motion aftereffect causes a visual stimulus to undergo apparent motion. An adapting stimulus, which moves in a specific direction, adapts motion-responsive neurons in the middle temporal area (V5) to that direction of motion. Viewing a second stimulus, a test stimulus, produces apparent motion in the direction opposite that of the initial stimulus. Neural networks involved in attention and working memory are also implicated in the motion aftereffect. There is still little known regarding the mechanisms of the motion aftereffect, despite extensive documentation in the literature. This review discusses established knowledge of the motion aftereffect, focusing primarily on the middle temporal area. Variants of the motion aftereffect that are in line with the established mechanism with be discussed, namely the phantom motion aftereffect and sensory-contingent motion aftereffects, which incorporate color and visual surroundings into the production of the motion aftereffect. This optical illusion provides insight into motion processing as well as memory

The Effects of Alcohol on the Developing Drosophila Nervous System

Ethanol is the most common human teratogen, contributing to fetal alcohol syndrome (FAS) when effects are the most severe. Key effects of fetal alcohol syndrome are observed in the nervous system. The high prevalence of prenatal alcohol exposure necessitates novel treatment and prevention methods. However, ethical issues prevent researching humans in utero. For this reason, the fruit fly Drosophila melanogaster has emerged as a model organism for studying FAS. Because Drosophila is a small and non-placental organism, its environment can be easily controlled, allowing for specific doses and time periods of ethanol exposure to be studied. This review discusses findings related to the impact of alcohol on the developing Drosophila nervous system. Findings related to reactive oxygen species (ROS) exposure, a consequence of prenatal alcohol exposure due to the metabolism of alcohol, are emphasized. Impacts of ethanol on insulin signaling and epidermal growth factors are also mentioned. Further research on Drosophila nervous system development under ethanol exposure may prove beneficial in the treatment and prevention of FAS

Inflammatory Mechanisms of Organ Crosstalk during Ischemic Acute Kidney Injury

Acute kidney injury (AKI) is a common complication during inpatient hospitalization, and clinical outcomes remain poor despite advancements in renal replacement therapy. AKI in the setting of multiple organ failure (MOF) remains a formidable challenge to clinicians and incurs an unacceptably high mortality rate. Kidney ischemia-reperfusion injury (IRI) incites a proinflammatory cascade and releases cellular and soluble mediators with systemic implications for remote organ injury. Evidence from preclinical models cites mechanisms of organ crosstalk during ischemic AKI including the expression of cellular adhesion molecules, lymphocyte trafficking, release of proinflammatory cytokines and chemokines, and modification of the host innate and adaptive immune response systems. In this paper, the influence of kidney IRI on systemic inflammation and distant organ injury will be examined. Recent experimental data and evolving concepts of organ crosstalk during ischemic AKI will also be discussed in detail

Impact of metformin on feeding, behavior, and metabolism in Drosophila melanogaster.

Metformin is a first-line drug used in the treatment of type II diabetes mellitus and is the 4th-most prescribed drug in the United States. It functions in lowering blood glucose levels and increasing insulin sensitivity. Despite its wide scale use, the degree to which it affects aspects of behavior and metabolism unrelated to diabetes is not fully understood. Recent studies have attempted to fill this gap, particularly in the context of metformin’s impact on lifespan. We decided to extend this research by focusing on measurable behaviors as well as traits related to metabolism and physiology. Using the fruit fly Drosophila melanogaster as a model organism, we investigated metformin’s impacts on food consumption, body weight, starvation resistance, and sleep. We observed preliminary evidence of increased feeding in Drosophila when given a metformin-supplemented diet. The same diet had an effect on body weight while making the flies less vulnerable to starvation stress. Metformin did not appear to have a significant impact on sleep patterns, except at low concentrations. These data show that metformin does cause multiple levels of side effects in the whole organism level. Given that the molecular pathways of metformin action are conserved between Drosophila and humans, similar effects on food consumption and weight may be found in human subjects treated with metformin. Future study should include an analysis of the molecular, genetic, and neuronal mechanisms of the above physiological and metabolic changes

Thermodynamic Forecasts of the Mediterranean Sea Acidification

Anthropogenic CO2 is a major driver of the present ocean acidification. This latter is threatening the marine ecosystems and has been identified as a major environmental and economic menace. This study aims to forecast from the thermodynamic equations, the acidification variation (ΔpH) of the Mediterranean waters over the next few decades and beyond this century. In order to do so, we calculated and fitted the theoretical values based upon the initial conditions from data of the 2013 MedSeA cruise. These estimates have been performed both for the Western and for the Eastern basins based upon their respective physical (temperature and salinity) and chemical (total alkalinity and total inorganic carbon) properties. The results allow us to point out four tipping points, including one when the Mediterranean Sea waters would become acid (pH<7). In order to provide an associated time scale to the theoretical results, we used two of the IPCC (2007) atmospheric CO2 scenarios. Under the most optimistic scenario of the “Special Report: Emissions Scenarios” (SRES) of the IPCC (2007), the results indicate that in 2100, pH may decrease down to 0.245 in the Western basin and down to 0.242 in the Eastern basin (compared to the pre-industrial pH). Whereas for the most pessimistic SRES scenario of the IPCC (2007), the results for the year 2100, forecast a pH decrease down to 0.462 and 0.457, for the Western and for the Eastern basins, respectively. Acidification, which increased unprecedentedly in recent years, will rise almost similarly in both Mediterranean basins only well after the end of this century. These results further confirm that both basins may become undersaturated (< 1) with respect to calcite and aragonite (at the base of the mixed layer depth), only in the far future (in a few centuries)

The Classical Limit of Quantum Mechanics and the Fejer Sum of the Fourier Series Expansion of a Classical Quantity

In quantum mechanics, the expectation value of a quantity on a quantum state, provided that the state itself gives in the classical limit a motion of a particle in a definite path, in classical limit goes over to Fourier series form of the classical quantity. In contrast to this widely accepted point of view, a rigorous calculation shows that the expectation value on such a state in classical limit exactly gives the Fej\'{e}r's arithmetic mean of the partial sums of the Fourier series

Inflammatory mechanisms of organ crosstalk during ischemic acute kidney injury

Acute kidney injury (AKI) is a common complication during inpatient hospitalization, and clinical outcomes remain poor despite advancements in renal replacement therapy. AKI in the setting of multiple organ failure (MOF) remains a formidable challenge to clinicians and incurs an unacceptably high mortality rate. Kidney ischemia-reperfusion injury (IRI) incites a proinflammatory cascade and releases cellular and soluble mediators with systemic implications for remote organ injury. Evidence from preclinical models cites mechanisms of organ crosstalk during ischemic AKI including the expression of cellular adhesion molecules, lymphocyte trafficking, release of proinflammatory cytokines and chemokines, and modification of the host innate and adaptive immune response systems. In this paper, the influence of kidney IRI on systemic inflammation and distant organ injury will be examined. Recent experimental data and evolving concepts of organ crosstalk during ischemic AKI will also be discussed in detail

Making Free Trade Fair

Philosophers have done very little work on what makes trade fair. Perhaps the most extensive discussion is Malgorzata Kurjanska and Mathias Risse’s article, “Fairness in Trade II: export subsidies and the fair trade movement.”2 In their article, Kurjanska and Risse consider the case for trade subsidies and the Fair Trade movement. They suggest that it is not permissible for developed countries to give their producers subsidies because doing so does not strike an appropriate balance between meeting the needs of the global poor and protecting domestic workers (Kurjanska and Risse, 2008: 34). Kurjanska and Risse also argue that the case for Fair Trade hinges, primarily, on whether or not it is part of the best development strategy for poor countries. They do not think Fair Trade is part of the best development strategy and, so, they believe purchasing Fair Trade certified goods is only acceptable because doing so does not constitute a large share of the market in traded goods. This chapter argues that the case against subsidies and Fair Trade Kurjanska and Risse present is much weaker than they make out. To the contrary, it argues that giving some subsidies and purchasing some Fair Trade certified goods may even be necessary to make trade fair. Section 11.2 starts by saying a few words about the normative framework Kurjanska and Risse adopt

Climatological variations of total alkalinity and total dissolved inorganic carbon in the Mediterranean Sea surface waters

Abstract. A compilation of data from several cruises between 1998 and 2013 was used to derive polynomial fits that estimate total alkalinity (AT) and total dissolved inorganic carbon (CT) from measurements of salinity and temperature in the Mediterranean Sea surface waters. The optimal equations were chosen based on the 10-fold cross-validation results and revealed that second- and third-order polynomials fit the AT and CT data respectively. The AT surface fit yielded a root mean square error (RMSE) of ± 10.6 μmol kg−1, and salinity and temperature contribute to 96 % of the variability. Furthermore, we present the first annual mean CT parameterization for the Mediterranean Sea surface waters with a RMSE of ± 14.3 μmol kg−1. Excluding the marginal seas of the Adriatic and the Aegean, these equations can be used to estimate AT and CT in case of the lack of measurements. The identified empirical equations were applied on the 0.25° climatologies of temperature and salinity, available from the World Ocean Atlas 2013. The 7-year averages (2005–2012) showed that AT and CT have similar patterns with an increasing eastward gradient. The variability is influenced by the inflow of cold Atlantic waters through the Strait of Gibraltar and by the oligotrophic and thermohaline gradient that characterize the Mediterranean Sea. The summer–winter seasonality was also mapped and showed different patterns for AT and CT. During the winter, the AT and CT concentrations were higher in the western than in the eastern basin. The opposite was observed in the summer where the eastern basin was marked by higher AT and CT concentrations than in winter. The strong evaporation that takes place in this season along with the ultra-oligotrophy of the eastern basin determines the increase of both AT and CT concentrations