Die räumliche Verteilung der Proteine in Feld- und Hausgrilleneiern

Zusammenfassung Die Proteinmuster verschiedener Eizonen wurden bei Feld- und Hausgrillen mit Hilfe der Disc-Elektrophorese untersucht. Deutliche quantitative wie auch qualitative Unterschiede in der Proteinzusammensetzung vorderer und hinterer Eiabschnitte ergaben sich für alle Arten. Dies gilt sowohl für unbefruchtete Eier als auch für die Entwicklungsstadien bis zur ersten Furchungsteilung. Betrachtet man kleinere Eibezirke (Vorderkappen, Mittelteil, Hinterkappen), läßt sich für einige Eiweiße eine gefälleartige Verteilung in der Eilängsachse nachweisen.

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The distribution of proteins in field and house cricket eggs

Summary The electrophoretic protein patterns of different regions in field and house crickets eggs were studied. All species showed marked quantitative and qualitative differences between anterior and posterior egg regions. This is valid for unfertilized eggs as well as early developmental stages. Investigations of smaller egg zones (anterior, middle, and posterior parts) revealed a gradient-like distribution of some of the proteins.

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Herrn Prof. Dr.Friedrich Seidel zum 70. Geburtstag gewidmet.

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Die vorliegenden Untersuchungen wurden von dem erstgenannten Autor mit Unterstützung der National Science Foundation (Grant G-21759) in dem Department of Biology der University of Virginia in Charlottesville, USA., begonnen. Der Deutschen Forschungsgemeinschaft danken wir für großzügige Unterstützung bei der Weiterführung der Arbeiten in Deutschland.     

Uric Acid and Thiocyanate as Competing Substrates of Lactoperoxidase

The physiological function of urate is poorly understood. It may act as a danger signal, an antioxidant, or a substrate for heme peroxidases. Whether it reacts sufficiently rapidly with lactoperoxidase (LPO) to act as a physiological substrate remains unknown. LPO is a mammalian peroxidase that plays a key role in the innate immune defense by oxidizing thiocyanate to the bactericidal and fungicidal agent hypothiocyanite. We now demonstrate that urate is a good substrate for bovine LPO. Urate was oxidized by LPO to produce the electrophilic intermediates dehydrourate and 5-hydroxyisourate, which decayed to allantoin. In the presence of superoxide, high yields of hydroperoxides were formed by LPO and urate. Using stopped-flow spectroscopy, we determined rate constants for the reaction of urate with compound I (k₁ = 1.1 × 10⁷ m⁻¹ s⁻¹) and compound II (k₂ = 8.5 × 10³ m⁻¹ s⁻¹). During urate oxidation, LPO was diverted from its peroxidase cycle because hydrogen peroxide reacted with compound II to give compound III. At physiologically relevant concentrations, urate competed effectively with thiocyanate, the main substrate of LPO for oxidation, and inhibited production of hypothiocyanite. Similarly, hypothiocyanite-dependent killing of Pseudomonas aeruginosa was inhibited by urate. Allantoin was present in human saliva and associated with the concentration of LPO. When hydrogen peroxide was added to saliva, oxidation of urate was dependent on its concentration and peroxidase activity. Our findings establish urate as a likely physiological substrate for LPO that will influence host defense and give rise to reactive electrophilic metabolites.     

Administrative gatekeeping - a third way between unrestricted patient advocacy and bedside rationing

The inevitable need for rationing of healthcare has apparently presented the medical profession with the dilemma of choosing the lesser of two evils. Physicians appear to be obliged to adopt either an implausible version of traditional professional ethics or an equally problematic ethics of bedside rationing. The former requires unrestricted advocacy of patients but prompts distrust, moral hazard and unfairness. The latter commits physicians to rationing at the bedside; but it is bound to introduce unfair inequalities among patients and lack of political accountability towards citizens. In this paper I shall argue that this dilemma is false, since a third intermediate alternative exists. This alternative, which I term 'administrative gatekeeping', makes it possible for physicians to be involved in rationing while at the same time being genuine advocates of their patients. According to this ideal, physicians are required to follow fair rules of rationing adopted at higher organizational levels within healthcare systems. At the same time, however, they are prohibited from including considerations of cost in their clinical decisions.     

Thermoregulation of water foraging honeybees—Balancing of endothermic activity with radiative heat gain and functional requirements

Foraging honeybees are subjected to considerable variations of microclimatic conditions challenging their thermoregulatory ability. Solar heat is a gain in the cold but may be a burden in the heat. We investigated the balancing of endothermic activity with radiative heat gain and physiological functions of water foraging Apis mellifera carnica honeybees in the whole range of ambient temperatures (T_a) and solar radiation they are likely to be exposed in their natural environment in Middle Europe.The mean thorax temperature (T_th) during foraging stays was regulated at a constantly high level (37.0-38.5 °C) in a broad range of T_a (3-30 °C). At warmer conditions (T_a = 30-39 °C) T_th increased to a maximal level of 45.3 °C. The endothermic temperature excess (difference of T_body − T_a of living and dead bees) was used to assess the endogenously generated temperature elevation as a correlate of energy turnover. Up to a T_a of ∼30 °C bees used solar heat gain for a double purpose: to reduce energetic expenditure and to increase T_th by about 1-3 °C to improve force production of flight muscles. At higher T_a they exhibited cooling efforts to get rid of excess heat. A high T_th also allowed regulation of the head temperature high enough to guarantee proper function of the bees’ suction pump even at low T_a. This shortened the foraging stays and this way reduced energetic costs. With decreasing T_a bees also reduced arrival body weight and crop loading to do both minimize costs and optimize flight performance.     

How City Dwellers Affect Their Resource Hinterland

This article links databases on household consumption, industrial production, economic turnover, employment, water use, and greenhouse gas emissions into a spatially explicit model. The causal sequence starts with households demanding a certain consumer basket. This demand requires production in a complex supply-chain network of interdependent industry sectors. Even though the household may be confined to a particular geographical location, say a dwelling in a city, the industries producing the indirect inputs for the commodities that the household demands will be dispersed all over Australia and probably beyond. Industrial production represents local points of economic activity, employment, water use, and emissions that have local economic, social, and environmental impacts. The consumer basket of a typical household is followed in Australia's two largest cities—Sydney and Melbourne—along its upstream supply chains and to numerous production sites within Australia. The spatial spread is described by means of a detailed regional interindustry model. Through industry-specific emissions profiles, industrial production is then translated into local impacts. We show that annually a typical household is responsible for producing approximately 80 tonnes of greenhouse gas emissions, uses around 3 million liters of water, causes about A$140,000 to circulate in the wider economy, and provides labor worth just under three full-time employment-years. We also introduce maps that visually demonstrate how a very localized household affects the environment across an entire continent. Our model is unprecedented in its spatial and sectoral detail, at least for Australia.     

Thermoregulation of water foraging wasps (Vespula vulgaris and Polistes dominulus)

A comparison of the thermoregulation of water foraging wasps (Vespula vulgaris, Polistes dominulus) under special consideration of ambient temperature and solar radiation was conducted. The body surface temperature of living and dead wasps was measured by infrared thermography under natural conditions in their environment without disturbing the insects’ behaviour. The body temperature of both of them was positively correlated with T_a and solar radiation. At moderate T_a (22–28 °C) the regression lines revealed mean thorax temperatures (T_th) of 35.5–37.5 °C in Vespula, and of 28.6–33.7 °C in Polistes. At high T_a (30–39 °C) T_th was 37.2–40.6 °C in Vespula and 37.0–40.8 °C in Polistes. The thorax temperature excess (T_th–T_a) increased at moderate T_a by 1.9 °C (Vespula) and 4.4 °C (Polistes) per kW⁻¹ m⁻². At high T_a it increased by 4.0 °C per kW⁻¹ m⁻² in both wasps. A comparison of the living water foraging Vespula and Polistes with dead wasps revealed a great difference in their thermoregulatory behaviour. At moderate T_a (22–28 °C) Vespula exhibited distinct endothermy in contrast to Polistes, which showed only a weak endothermic activity. At high T_a (30–39 °C) Vespula reduced their active heat production, and Polistes were always ectothermic. Both species exhibited an increasing cooling effort with increasing insolation and ambient temperature.     

Hypercapnia is a Possible Determinant of the Function of the Blood-Cerebrospinal Fluid Barrier in Amyotrophic Lateral Sclerosis

Elevated cerebrospinal fluid (CSF)/serum quotients of albumin (Q_Alb) may occur in motor neuron diseases (MND) including amyotrophic lateral sclerosis (ALS), but the pathophysiologic mechanisms underlying these alterations are unclear. Evidence from animal experiments suggests that the arterial carbon dioxide level might affect the Q_Alb, i.e. the function of the blood-CSF barrier (BCB). We therefore compared basic CSF parameters in different forms of MND (ALS, n = 105; lower motor neuron diseases, n = 12; and upper motor neuron diseases, n = 7) and investigated the relationship between elevated Q_Alb and the arterial partial pressure of carbon dioxide (pCO₂) in ALS where respiratory insufficiency leads to hypercapnia in the course of the disease. Pathologic elevations of Q_Alb occurred in 32 of 124 MND patients. In ALS, Q_Alb significantly correlated with the arterial pCO₂ (r = 0.454; P = 0.001; n = 45). These data indicate that BCB dysfunction is a frequent finding in different forms of MND and may reflect distinct pathophysiological mechanisms. In ALS, an important underlying mechanism might be the influence of the arterial pCO₂ which may alter the CSF flow.