Octopamine integrates the status of internal energy supply into the formation of food-related memories

The brain regulates food intake in response to internal energy demands and food availability. However, can internal energy storage influence the type of memory that is formed? We show that the duration of starvation determines whether Drosophila melanogaster forms appetitive short-term or longer-lasting intermediate memories. The internal glycogen storage in the muscles and adipose tissue influences how intensely sucrose-associated information is stored. Insulin-like signaling in octopaminergic reward neurons integrates internal energy storage into memory formation. Octopamine, in turn, suppresses the formation of long-term memory. Octopamine is not required for short-term memory because octopamine-deficient mutants can form appetitive short-term memory for sucrose and to other nutrients depending on the internal energy status. The reduced positive reinforcing effect of sucrose at high internal glycogen levels, combined with the increased stability of food-related memories due to prolonged periods of starvation, could lead to increased food intake.

From Natural Behavior to Drug Screening: Invertebrates as Models to Study Mechanisms Associated with Alcohol Use Disorders

Humans consume ethanol-containing beverages, which may cause an uncontrollable or difficult-to-control intake of ethanol-containing liquids and may result in alcohol use disorders. How the transition at the molecular level from "normal" ethanol-associated behaviors to addictive behaviors occurs is still unknown. One problem is that the components contributing to normal ethanol intake and their underlying molecular adaptations, especially in neurons that regulate behavior, are not clear. The fruit fly Drosophila melanogaster and the earthworm Caenorhabditis elegans show behavioral similarities to humans such as signs of intoxication, tolerance, and withdrawal. Underlying the phenotypic similarities, invertebrates and vertebrates share mechanistic similarities. For example in Drosophila melanogaster, the dopaminergic neurotransmitter system regulates the positive reinforcing properties of ethanol and in Caenorhabditis elegans, serotonergic neurons regulate feeding behavior. Since these mechanisms are fundamental molecular mechanisms and are highly conserved, invertebrates are good models for uncovering the basic principles of neuronal adaptation underlying the behavioral response to ethanol. This review will focus on the following aspects that might shed light on the mechanisms underlying normal ethanol-associated behaviors. First, the current status of what is required at the behavioral and cellular level to respond to naturally occurring levels of ethanol is summarized. Low levels of ethanol delay the development and activate compensatory mechanisms that in turn might be beneficial for some aspects of the animal's physiology. Repeated exposure to ethanol however might change brain structures involved in mediating learning and memory processes. The smell of ethanol is already a key component in the environment that is able to elicit behavioral changes and molecular programs. Minimal networks have been identified that regulate normal ethanol consumption. Other environmental factors that influence ethanol-induced behaviors include the diet, dietary supplements, and the microbiome. Second, the molecular mechanisms underlying neuronal adaptation to the cellular stressor ethanol are discussed. Components of the heat shock and oxidative stress pathways regulate adaptive responses to low levels of ethanol and in turn change behavior. The adaptive potential of the brain cells is challenged when the organism encounters additional cellular stressors caused by aging, endosymbionts or environmental toxins or excessive ethanol intake. Finally, to underline the conserved nature of these mechanisms between invertebrates and higher organisms, recent approaches to identify drug targets for ethanol-induced behaviors are provided. Already approved drugs regulate ethanol-induced behaviors and they do so in part by interfering with cellular stress pathways. In addition, invertebrates have been used to identify new compounds targeting molecules involved in the regulation in ethanol withdrawal-like symptoms. This review primarily highlights the advances of the last 5 years concerning Drosophila melanogaster, but also provides intriguing examples of Caenorhabditis elegans and Apis mellifera in support.

Mutation of the Drosophila melanogaster serotonin transporter dSERT impacts sleep, courtship, and feeding behaviors

The Serotonin Transporter (SERT) regulates extracellular serotonin levels and is the target of most current drugs used to treat depression. The mechanisms by which inhibition of SERT activity influences behavior are poorly understood. To address this question in the model organism Drosophila melanogaster, we developed new loss of function mutations in Drosophila SERT (dSERT). Previous studies in both flies and mammals have implicated serotonin as an important neuromodulator of sleep, and our newly generated dSERT mutants show an increase in total sleep and altered sleep architecture that is mimicked by feeding the SSRI citalopram. Differences in daytime versus nighttime sleep architecture as well as genetic rescue experiments unexpectedly suggest that distinct serotonergic circuits may modulate daytime versus nighttime sleep. dSERT mutants also show defects in copulation and food intake, akin to the clinical side effects of SSRIs and consistent with the pleomorphic influence of serotonin on the behavior of D. melanogaster. Starvation did not overcome the sleep drive in the mutants and in male dSERT mutants, the drive to mate also failed to overcome sleep drive. dSERT may be used to further explore the mechanisms by which serotonin regulates sleep and its interplay with other complex behaviors.

Ethanol-guided behavior in Drosophila larvae

Chemosensory signals allow vertebrates and invertebrates not only to orient in its environment toward energy-rich food sources to maintain nutrition but also to avoid unpleasant or even poisonous substrates. Ethanol is a substance found in the natural environment of Drosophila melanogaster. Accordingly, D. melanogaster has evolved specific sensory systems, physiological adaptations, and associated behaviors at its larval and adult stage to perceive and process ethanol. To systematically analyze how D. melanogaster larvae respond to naturally occurring ethanol, we examined ethanol-induced behavior in great detail by reevaluating existing approaches and comparing them with new experiments. Using behavioral assays, we confirm that larvae are attracted to different concentrations of ethanol in their environment. This behavior is controlled by olfactory and other environmental cues. It is independent of previous exposure to ethanol in their food. Moreover, moderate, naturally occurring ethanol concentration of 4% results in increased larval fitness. On the contrary, higher concentrations of 10% and 20% ethanol, which rarely or never appear in nature, increase larval mortality. Finally, ethanol also serves as a positive teaching signal in learning and memory and updates valence associated with simultaneously processed odor information. Since information on how larvae perceive and process ethanol at the genetic and neuronal level is limited, the establishment of standardized assays described here is an important step towards their discovery.

ERR and dPECR Suggest a Link Between Neuroprotection and the Regulation of Ethanol Consumption Preference

Reconsumption of ethanol after withdrawal is a hallmark for relapse in recovering patients with alcohol use disorders. We show that the preference of Drosophila melanogaster to reconsume ethanol after abstinence shares mechanistic similarities to human behavior by feeding the antirelapse drug acamprosate to flies and reducing the ethanol consumption preference. The Drosophila cellular stress mutant hangover also reduced ethanol consumption preference. Together with the observation that an increasing number of candidate genes identified in a genome-wide association study on alcohol use disorders are involved in the regulation of cellular stress, the results suggest that cellular stress mechanisms might regulate the level of ethanol reconsumption after abstinence. To address this, we analyzed mutants of candidate genes involved in the regulation of cellular stress for their ethanol consumption level after abstinence and cellular stress response to free radicals. Since hangover encodes a nuclear RNA-binding protein that regulates transcript levels, we analyzed the interactions of candidate genes on transcript and protein level. The behavioral analysis of the mutants, the analysis of transcript levels, and protein interactions suggested that at least two mechanisms regulate ethanol consumption preference after abstinence-a nuclear estrogen-related receptor-hangover-dependent complex and peroxisomal trans-2-enoyl-CoA reductase (dPECR)-dependent component in peroxisomes. The loss of estrogen-like receptor and dPECR in neurons share a protective function against oxidative stress, suggesting that the neuroprotective function of genes might be a predictor for genes involved in the regulation of ethanol reconsumption after abstinence.

Monitoring the quality of frozen-thawed venous segments using bioimpedance spectroscopy

OBJECTIVE

Storage at temperatures as low as -80 °C and below (cryopreservation) is considered a method for long-term preservation of cells and tissues, and especially blood vessel segments, which are to be used for clinical operations such as transplantation. However, the freezing and thawing processes themselves can induce injuries to the cells and tissue by damaging the structure and consequently functionality of the cryopreserved tissue. In addition, the level of damage is dependent on the rate of cooling and warming used during the freezing-thawing process. Current methods for monitoring the viability and integrity of cells and tissues after going through the freezing-thawing cycle are usually invasive and destructive to the cells and tissues. Therefore, employing monitoring methods which are not destructive to the cryopreserved tissues, such as bioimpedance measurement techniques, is necessary. In this study we aimed to design a bioimpedance measurement setup to detect changes in venous segments after freezing-thawing cycles in a noninvasive manner.

APPROACH

A bioimpedance spectroscopy measurement technique with a two-electrode setup was employed to monitor ovine jugular vein segments after each cycle during a process of seven freezing-thawing cycles.

MAIN RESULTS

The results demonstrated changes in the impedance spectra of the measured venous segments after each freezing-thawing cycle.

SIGNIFICANCE

This indicates that bioimpedance spectroscopy has the potential to be developed into a novel method for non-invasive and non-destructive monitoring of the viability of complex tissue after cryopreservation.

Unraveling the Mechanisms of Behaviors Associated With AUDs Using Flies and Worms

Alcohol use disorders (AUDs) are very common worldwide and negatively affect both individuals and societies. To understand how normal behavior turns into uncontrollable use of alcohol, several approaches have been utilized in the last decades. However, we still do not completely understand how AUDs evolve or how they are maintained in the brains of affected individuals. In addition, efficient and effective treatment is still in need of development. This review focuses on alternative approaches developed over the last 20 years using Drosophila melanogaster (Drosophila) and Caenorhabditis elegans (C. elegans) as genetic model systems to determine the mechanisms underlying the action of ethanol (EtOH) and behaviors associated with AUDs. All the results and insights of studies over the last 20 years cannot be comprehensively summarized. Thus, a few prominent examples are provided highlighting the principles of the genes and mechanisms that have been uncovered and are involved in the action of EtOH at the cellular level. In addition, examples are provided of the genes and mechanisms that regulate behaviors relevant to acquiring and maintaining excessive alcohol intake, such as decision making, reward and withdrawal, and/or relapse regulation. How the insight gained from the results of Drosophila and C. elegans models can be translated to higher organisms, such as rodents and/or humans, is discussed, as well as whether these insights have any relevance or impact on our understanding of the mechanisms underlying AUDs in humans. Finally, future directions are presented that might facilitate the identification of drugs to treat AUDs.

Octopamine Shifts the Behavioral Response From Indecision to Approach or Aversion in Drosophila melanogaster

Animals must make constant decisions whether to respond to external sensory stimuli or not to respond. The activation of positive and/or negative reinforcers might bias the behavioral response towards approach or aversion. To analyze whether the activation of the octopaminergic neurotransmitter system can shift the decision between two identical odor sources, we active in Drosophila melanogaster different sets of octopaminergic neurons using optogenetics and analyze the choice of the flies using a binary odor trap assay. We show that the release of octopamine from a set of neurons and not acetylcholine acts as positive reinforcer for one food odor source resulting in attraction. The activation of a subset of these neurons causes the opposite behavior and results in aversion. This aversion is due to octopamine release and not tyramine, since in Tyramine-β-hydroxylase mutants (Tβh) lacking octopamine, the aversion is suppressed. We show that when given the choice between two different attractive food odor sources the activation of the octopaminergic neurotransmitter system switches the attraction for ethanol-containing food odor to a less attractive food odor. Consistent with the requirement for octopamine in biasing the behavioral outcome, Tβh mutants fail to switch their attraction. The execution of attraction does not require octopamine but rather initiation of the behavior or a switch of the behavioral response. The attraction to ethanol also depends on octopamine. Pharmacological increases in octopamine signaling in Tβh mutants increase ethanol attraction and blocking octopamine receptor function reduces ethanol attraction. Taken together, octopamine in the central brain orchestrates behavioral outcomes by biasing the decision of the animal towards food odors. This finding might uncover a basic principle of how octopamine gates behavioral outcomes in the brain.

Einflüsse auf den ruminalen Protozoenbesatz des Rindes (in vitro)

Die Wirkung einer subklinischen Pansenazidose auf die Protozoenpopulation ohne und mit Zusatz von Thiamin wurde in einem Langzeitinkubationssystem (RUSITEC) mit sechs Fermentern überprüft [Versuchsdauer: 25 Tage; Pufferzufluss 180 μl/min zur Einstellung eines pH-Werts < 6; tägliche Beladung Experiment 1, Tag 1- 9: sechs Fermenter mit Heu (HE) + Weizenmehl (WM); Tag 10-17: zwei Fermenter mit HE + WM, vier Fermenter mit HE + WM + 0,3 mg Thiamin; Tag 18-25 wie Tag 1-9; Beladung Experiment 2, Tag 1-9: sechs Fermenter mit HE + WM + 0,3 mg Thiamin; Tag 10-17: zwei Fermenter mit HE + WM + 0,3 mg Thiamin, vier Fermenter mit HE + WM; Tag 18-25 wie Tag 1- 9]. Unter Bedingungen einer subklinischen Pansenazidose (pH-Wert < 6) verschwanden alle Protozoen innerhalb von 14, die mittleren bereits nach acht Tagen (normal 1 × 103 bis 25 × 106 Protozoen/ml Pansensaft, davon anteilig mittelgroße: 6-18%). Bei Thiaminsupplementierung von Versuchsbeginn an hielt sich die Gesamtprotozoenzahl insgesamt auf einem Niveau von > 2,4 × 104 Protozoen/ml Pansensaft. Die mittlere Fraktion ging kontinuierlich bis Tag 11 auf Werte unter 800 Protozoen/ ml Pansensaft zurück. Die großen Protozoen waren während beider Experimente gar nicht zu finden (normal anteilig 0-3% an der Gesamtpopulation). Eine subklinische Pansenazidose wirkt sich offensichtlich negativ auf die Protozoenpopulation aus. Dieser Effekt kann durch die Thiaminsupplementierung kompensiert werden. Der Protozoenverlust im Pansensaft als brauchbarer Parameter zur Aufdeckung subklinischer Pansenazidosen sowie der prophylaktische Einsatz von Thiamin in der Fütterungspraxis hochleistender Wiederkäuer sollte in Erwägung gezogen werden.

Key Odorants Regulate Food Attraction in Drosophila melanogaster

In insects, the search for food is highly dependent on olfactory sensory input. Here, we investigated whether a single key odorant within an odor blend or the complexity of the odor blend influences the attraction of Drosophila melanogaster to a food source. A key odorant is defined as an odorant that elicits a difference in the behavioral response when two similar complex odor blends are offered. To validate that the observed behavioral responses were elicited by olfactory stimuli, we used olfactory co-receptor Orco mutants. We show that within a food odor blend, ethanol functions as a key odorant. In addition to ethanol other odorants might serve as key odorants at specific concentrations. However, not all odorants are key odorants. The intensity of the odor background influences the attractiveness of the key odorants. Increased complexity is only more attractive in a concentration-dependent range for single compounds in a blend. Orco is necessary to discriminate between two similarly attractive odorants when offered as single odorants and in food odor blends, supporting the importance of single odorant recognition in odor blends. These data strongly indicate that flies use more than one strategy to navigate to a food odor source, depending on the availability of key odorants in the odor blend and the alternative odor offered.

The CApillary FEeder Assay Measures Food Intake in Drosophila melanogaster

For most animals, feeding is an essential behavior for securing survival, and it influences development, locomotion, health and reproduction. Ingestion of the right type and quantity of food therefore has a major influence on quality of life. Research on feeding behavior focuses on the underlying processes that ensure actual feeding and unravels the role of factors regulating internal energy homeostasis and the neuronal bases of decision-making. The model organism Drosophila melanogaster, with its great variety of genetically traceable tools for labeling and manipulating single neurons, allows mapping of neuronal networks and identification of molecular signaling cascades involved in the regulation of food intake. This report demonstrates the CApillary FEeder assay (CAFE) and shows how to measure food intake in a group of flies for time spans ranging from hours to days. This easy-to-use assay consists of glass capillaries filled with liquid food that flies can freely access and feed on. Food consumption in the assay is accurately determined using simple measurement tools. Herein we describe step-by-step the method from setup to successful execution of the CAFE assay, and provide practical examples to analyze the food intake of a group of flies under controlled conditions. The reader is guided through possible limitations of the assay, and advantages and disadvantages of the method compared to other feeding assays in D. melanogaster are evaluated.

A Single Pair of Serotonergic Neurons Counteracts Serotonergic Inhibition of Ethanol Attraction in Drosophila

Attraction to ethanol is common in both flies and humans, but the neuromodulatory mechanisms underlying this innate attraction are not well understood. Here, we dissect the function of the key regulator of serotonin signaling—the serotonin transporter–in innate olfactory attraction to ethanol in Drosophila melanogaster. We generated a mutated version of the serotonin transporter that prolongs serotonin signaling in the synaptic cleft and is targeted via the Gal4 system to different sets of serotonergic neurons. We identified four serotonergic neurons that inhibit the olfactory attraction to ethanol and two additional neurons that counteract this inhibition by strengthening olfactory information. Our results reveal that compensation can occur on the circuit level and that serotonin has a bidirectional function in modulating the innate attraction to ethanol. Given the evolutionarily conserved nature of the serotonin transporter and serotonin, the bidirectional serotonergic mechanisms delineate a basic principle for how random behavior is switched into targeted approach behavior.

Serological survey of Bartonella spp., Borrelia burgdorferi, Brucella spp., Coxiella burnetii, Francisella tularensis, Leptospira spp., Echinococcus, Hanta-, TBE- and XMR-virus infection in employees of two forestry enterprises in North Rhine-Westphalia, Germany, 2011-2013

We initiated a survey to collect basic data on the frequency and regional distribution of various zoonoses in 722 employees of forestry enterprises in the German state of North Rhine-Westphalia (NRW) from 2011 to 2013. Exposures associated with seropositivity were identified to give insight into the possible risk factors for infection with each pathogen. 41.2% of participants were found to be seropositive for anti-Bartonella IgG, 30.6% for anti-Borrelia burgdorferi IgG, 14.2% for anti-Leptospira IgG, 6.5% for anti-Coxiella burnetii IgG, 6.0% for anti-Hantavirus IgG, 4.0% for anti-Francisella tularensis IgG, 3.4% for anti-TBE-virus IgG, 1.7% for anti-Echinococcus IgG, 0.0% for anti-Brucella IgG and anti-XMRV IgG. Participants seropositive for B. burgdorferi were 3.96 times more likely to be professional forestry workers (univariable analysis: OR 3.96; 95% CI 2.60-6.04; p<0.001); and participants seropositive for Hantavirus 3.72 times more likely (univariable analysis: OR 3.72; 95% CI 1.44-9.57; p=0.007). This study found a surprisingly high percentage of participants seropositive for anti-B. henselae IgG and for anti-F. tularensis IgG. The relatively high seroprevalence for anti-Leptospira IgG seen in this study could be related to living conditions rather than to exposure at work. No specific risk for exposure to C. burnetii and Echinococcus was identified, indicating that neither forestry workers nor office workers represent a risk population and that NRW is not a typical endemic area. Forestry workers appear to have higher risk for contact with B. burgdorferi-infected ticks and a regionally diverse risk for acquiring Hantavirus-infection. The regional epidemiology of zoonoses is without question of great importance for public health. Knowledge of the regional risk factors facilitates the development of efficient prevention strategies and the implementation of such prevention measures in a sustainable manner.

XRCC5 as a risk gene for alcohol dependence: evidence from a genome-wide gene-set-based analysis and follow-up studies in Drosophila and humans

Genetic factors have as large role as environmental factors in the etiology of alcohol dependence (AD). Although genome-wide association studies (GWAS) enable systematic searches for loci not hitherto implicated in the etiology of AD, many true findings may be missed owing to correction for multiple testing. The aim of the present study was to circumvent this limitation by searching for biological system-level differences, and then following up these findings in humans and animals. Gene-set-based analysis of GWAS data from 1333 cases and 2168 controls identified 19 significantly associated gene-sets, of which 5 could be replicated in an independent sample. Clustered in these gene-sets were novel and previously identified susceptibility genes. The most frequently present gene, ie in 6 out of 19 gene-sets, was X-ray repair complementing defective repair in Chinese hamster cells 5 (XRCC5). Previous human and animal studies have implicated XRCC5 in alcohol sensitivity. This phenotype is inversely correlated with the development of AD, presumably as more alcohol is required to achieve the desired effects. In the present study, the functional role of XRCC5 in AD was further validated in animals and humans. Drosophila mutants with reduced function of Ku80-the homolog of mammalian XRCC5-due to RNAi silencing showed reduced sensitivity to ethanol. In humans with free access to intravenous ethanol self-administration in the laboratory, the maximum achieved blood alcohol concentration was influenced in an allele-dose-dependent manner by genetic variation in XRCC5. In conclusion, our convergent approach identified new candidates and generated independent evidence for the involvement of XRCC5 in alcohol dependence.

Octopamine indirectly affects proboscis extension response habituation in Drosophila melanogaster by controlling sucrose responsiveness

Octopamine is an important neurotransmitter in insects with multiple functions. Here, we investigated the role of this amine in a simple form of learning (habituation) in the fruit fly Drosophila melanogaster. Specifically, we asked if octopamine is necessary for normal habituation of a proboscis extension response (PER) to different sucrose concentrations. In addition, we analyzed the relationship between responsiveness to sucrose solutions applied to the tarsus and habituation of the proboscis extension response in the same individual. The Tyramine-β-hydroxylase (Tβh) mutant lacks the enzyme catalyzing the final step of octopamine synthesis. This mutant was significantly less responsive to sucrose than controls. The reduced responsiveness directly led to faster habituation. Systemic application of octopamine or induction of octopamine synthesis by Tβh expression in a cluster of octopaminergic neurons within the suboesophageal ganglion restored sucrose responsiveness and habituation of octopamine mutants to control level. Further analyses imply that the reduced sucrose responsiveness of Tβh mutants is related to a lower sucrose preference, probably due to a changed carbohydrate metabolism, since Tβh mutants survived significantly longer under starved conditions. These findings suggest a pivotal role for octopamine in regulating sucrose responsiveness in fruit flies. Further, octopamine indirectly influences non-associative learning and possibly associative appetitive learning by regulating the evaluation of the sweet component of a sucrose reward.

Prevalence of suicide attempts in pathological gamblers in a nationwide Austrian treatment sample

BACKGROUND

For pathological gambling (PG), a 12-month prevalence rate of up to 0.66% has been reported. Multiple financial, occupational and relationship problems and losses, humiliation of the person and the environment are possible side effects and may lead to hopelessness, suicidal ideation and suicidal behavior. Suicide attempt rates among pathological gamblers of between 4% and 40% and suicidal ideation of between 12% and 92% have been reported.

AIM

This study aims at assessing the prevalence of suicide attempts in PG and at elucidating differences between the patients with and without suicide attempt history (SAH) in a large nationwide Austrian sample.

METHODS

Between 2002 and 2011, the Austrian Society for the Research of Non-Substance Related Addiction collected 862 questionnaires of pathological gamblers undergoing outpatient and inpatient treatment for PG in Austria.

RESULTS

(a) Of all pathological gamblers, 9.7% had an SAH. (b) The SAH group suffered significantly more from a comorbid disorder and was more often in previous inpatient treatments. (c) The SAH patients had a longer time of an abstinence period in their PG career.

DISCUSSION

One in 10 pathological gamblers has an SAH, demonstrating the relevance of suicidality in this population. Significant differences for several parameters were found for PG with and without SAH. However, a regression analysis only explained 15% of the variance. This suggests that suicidality must be considered in pathological gamblers in general.

A systems medicine research approach for studying alcohol addiction

According to the World Health Organization, about 2 billion people drink alcohol. Excessive alcohol consumption can result in alcohol addiction, which is one of the most prevalent neuropsychiatric diseases afflicting our society today. Prevention and intervention of alcohol binging in adolescents and treatment of alcoholism are major unmet challenges affecting our health-care system and society alike. Our newly formed German SysMedAlcoholism consortium is using a new systems medicine approach and intends (1) to define individual neurobehavioral risk profiles in adolescents that are predictive of alcohol use disorders later in life and (2) to identify new pharmacological targets and molecules for the treatment of alcoholism. To achieve these goals, we will use omics-information from epigenomics, genetics transcriptomics, neurodynamics, global neurochemical connectomes and neuroimaging (IMAGEN; Schumann et al. ) to feed mathematical prediction modules provided by two Bernstein Centers for Computational Neurosciences (Berlin and Heidelberg/Mannheim), the results of which will subsequently be functionally validated in independent clinical samples and appropriate animal models. This approach will lead to new early intervention strategies and identify innovative molecules for relapse prevention that will be tested in experimental human studies. This research program will ultimately help in consolidating addiction research clusters in Germany that can effectively conduct large clinical trials, implement early intervention strategies and impact political and healthcare decision makers.

Neuronal basis of innate olfactory attraction to ethanol in Drosophila

The decision to move towards a mating partner or a food source is essential for life. The mechanisms underlying these behaviors are not well understood. Here, we investigated the role of octopamine - the invertebrate analogue of noradrenaline - in innate olfactory attraction to ethanol. We confirmed that preference is caused via an olfactory stimulus by dissecting the function of the olfactory co-receptor Orco (formally known as OR83b). Orco function is not required for ethanol recognition per se, however it plays a role in context dependent recognition of ethanol. Odor-evoked ethanol preference requires the function of Tbh (Tyramine β hydroxalyse), the rate-limiting enzyme of octopamine synthesis. In addition, neuronal activity in a subset of octopaminergic neurons is necessary for olfactory ethanol preference. Notably, a specific neuronal activation pattern of tyraminergic/octopaminergic neurons elicit preference and is therefore sufficient to induce preference. In contrast, dopamine dependent increase in locomotor activity is not sufficient for olfactory ethanol preference. Consistent with the role of noradrenaline in mammalian drug induced rewards, we provide evidence that in adult Drosophila the octopaminergic neurotransmitter functions as a reinforcer and that the molecular dissection of the innate attraction to ethanol uncovers the basic properties of a response selection system.

Inter-leg coordination in the control of walking speed in Drosophila

Legged locomotion is the most common behavior of terrestrial animals and it is assumed to have become highly optimized during evolution. Quadrupeds, for instance, use distinct gaits that are optimal with regard to metabolic cost and have characteristic kinematic features and patterns of inter-leg coordination. In insects, the situation is not as clear. In general, insects are able to alter inter-leg coordination systematically with locomotion speed, producing a continuum of movement patterns. This notion, however, is based on the study of several insect species, which differ greatly in size and mass. Each of these species tends to walk at a rather narrow range of speeds. We have addressed these issues by examining four strains of Drosophila, which are similar in size and mass, but tend to walk at different speed ranges. Our data suggest that Drosophila controls its walking speed almost exclusively via step frequency. At high walking speeds, we invariably found tripod coordination patterns, the quality of which increased with speed as indicated by a simple measure of tripod coordination strength (TCS). At low speeds, we also observed tetrapod coordination and wave gait-like walking patterns. These findings not only suggest a systematic speed dependence of inter-leg movement patterns but also imply that inter-leg coordination is flexible. This was further supported by amputation experiments in which we examined walking behavior in animals after the removal of a hindleg. These animals show immediate adaptations in body posture, leg kinematics and inter-leg coordination, thereby maintaining their ability to walk.

[Treatment of complications after arteriovenous access surgery]

The choice of potential options for an arteriovenous (AV) access is limited for each individual patient. Complications shorten the maximum life span of any AV access. This paper stresses the importance of recognizing complications in time so as to initiate early and adequate therapy which are explained in further detail. Existing vascular accesses should be used as long as possible while maintaining further alternatives for future AV access surgery.

Reduced soluble receptor for advanced glycation end-products (sRAGE) scavenger capacity precedes pre-eclampsia in Type 1 diabetes

OBJECTIVE

Increased advanced glycation end-products (AGEs) and their soluble receptors (sRAGE) have been implicated in the pathogenesis of pre-eclampsia (PE). However, this association has not been elucidated in pregnancies complicated by diabetes. We aimed to investigate the serum levels of these factors in pregnant women with Type 1 diabetes mellitus (T1DM), a condition associated with a four-fold increase in PE.

DESIGN

Prospective study in women with T1DM at 12.2 ± 1.9, 21.6 ± 1.5 and 31.5 ± 1.7 weeks of gestation [mean ± standard deviation (SD); no overlap] before PE onset.

SETTING

Antenatal clinics.

POPULATION

Pregnant women with T1DM (n = 118; 26 developed PE) and healthy nondiabetic pregnant controls (n = 21).

METHODS

Maternal serum levels of sRAGE (total circulating pool), N(ε)-(carboxymethyl)lysine (CML), hydroimidazolone (methylglyoxal-modified proteins) and total AGEs were measured by immunoassays.

MAIN OUTCOME MEASURES

Serum sRAGE and AGEs in pregnant women with T1DM who subsequently developed PE (DM PE+) versus those who remained normotensive (DM PE-).

RESULTS

In DM PE+ versus DM PE-, sRAGE was significantly lower in the first and second trimesters, prior to the clinical manifestation of PE (P < 0.05). Further, reflecting the net sRAGE scavenger capacity, sRAGE:hydroimidazolone was significantly lower in the second trimester (P < 0.05) and sRAGE:AGE and sRAGE:CML tended to be lower in the first trimester (P < 0.1) in women with T1DM who subsequently developed PE versus those who did not. These conclusions persisted after adjusting for prandial status, glycated haemoglobin (HbA1c), duration of diabetes, parity and mean arterial pressure as covariates.

CONCLUSIONS

In the early stages of pregnancy, lower circulating sRAGE levels, and the ratio of sRAGE to AGEs, may be associated with the subsequent development of PE in women with T1DM.

Three dopamine pathways induce aversive odor memories with different stability

Animals acquire predictive values of sensory stimuli through reinforcement. In the brain of Drosophila melanogaster, activation of two types of dopamine neurons in the PAM and PPL1 clusters has been shown to induce aversive odor memory. Here, we identified the third cell type and characterized aversive memories induced by these dopamine neurons. These three dopamine pathways all project to the mushroom body but terminate in the spatially segregated subdomains. To understand the functional difference of these dopamine pathways in electric shock reinforcement, we blocked each one of them during memory acquisition. We found that all three pathways partially contribute to electric shock memory. Notably, the memories mediated by these neurons differed in temporal stability. Furthermore, combinatorial activation of two of these pathways revealed significant interaction of individual memory components rather than their simple summation. These results cast light on a cellular mechanism by which a noxious event induces different dopamine signals to a single brain structure to synthesize an aversive memory.

New moves in motor control

Motor behaviour results from information processing across multiple neural networks acting at all levels from initial selection of the behaviour to its final generation. Understanding how motor behaviour is produced requires identifying the constituent neurons of these networks, their cellular properties, and their pattern of synaptic connectivity. Neural networks have been traditionally studied with neurophysiological and neuroanatomical approaches. These approaches have been highly successful in particularly suitable 'model' preparations, typically ones in which the numbers of neurons in the networks were relatively small, neural network composition was unvarying across individual animals, and the preparations continued to produce fictive motor patterns in vitro. However, analysing networks without these characteristics, and analysing the complete ensemble of networks that cooperatively generate behaviours, is difficult with these approaches. Recently developed molecular and neurogenetic tools provide additional avenues for analysing motor networks by allowing individual or groups of neurons within networks to be manipulated in novel ways and allowing experiments to be performed not only in vitro but also in vivo. We review here some of the new insights into motor network function that these advances have provided and indicate how these advances might bridge gaps in our understanding of motor control. To these ends, we first review motor neural network organisation highlighting cross-phylum principles. We then use prominent examples from the field to show how neurogenetic approaches can complement classical physiological studies, and identify additional areas where these approaches could be advantageously applied.

Haloarchaeal myovirus φCh1 harbours a phase variation system for the production of protein variants with distinct cell surface adhesion specificities

The φCh1 myovirus, which infects the haloalkaliphilic archaeon Natrialba magadii, contains an invertible region that comprises the convergent open reading frames (ORFs) 34 and 36, which code for the putative tail fibre proteins gp34 and gp36 respectively. The inversion leads to an exchange of the C-termini of these proteins, thereby creating different types of tail fibres. Gene expression experiments revealed that only ORF34 is transcribed, indicating that φCh1 produces tail fibre proteins exclusively from this particular ORF. Only one of the two types of tail fibres encoded by ORF34 is able to bind to Nab. magadii in vitro. This is reflected by the observation that during the early phases of the infection cycle, the lysogenic strain L11 carries its invertible region exclusively in the orientation that produces that specific type of tail fibre. Obviously, Nab. magadii can only be infected by viruses carrying this particular type of tail fibre. By mutational analysis, the binding domain of gp34 was localized to the C-terminal part of the protein, particularly to a galactose-binding domain. The involvement of galactose residues in cell adhesion was supported by the observation that the addition of α-D-galactose to purified gp34 or whole virions prevented their attachment to Nab. magadii.

The serotonin transporter expression in Drosophila melanogaster

The serotonin transporter is an important regulator of serotonergic signaling. In order to analyze where the Drosophila melanogaster ortholog of the mammalian serotonin transporter (dSERT) is expressed in the nervous system, a dSERT antibody serum was used. Ectopic expression studies and loss of function analysis revealed that the dSERT antibody serum specifically recognizes dSERT. It was shown that in the embryonic nervous system dSERT is expressed in a subset of Engrailed-positive neurons. In the larval brain, dSERT is exclusively expressed in serotonergic neurons, all of which express dSERT. dSERT-positive neurons surround almost all brain neuropiles. In the mushroom body of the adult brain, extrinsic serotonergic neurons expressing dSERT engulf the mushroom body lobes. These neurons show regional differences in dSERT and serotonin expression. At the presynaptic terminals, serotonin release is sterically linked to serotonin reuptake. In contrast to this, there are other areas in serotonergic neurons where dSERT expression and/or function are uncoupled from synaptic neurotransmitter recycling and serotonin release. The localization pattern of dSERT can be employed to further understanding and analysis of serotonergic networks.

Wechselbeziehungen zwischen dem Milchleistungsniveau, der Fruchtbarkeit und dem Krankheitsgeschehen bei Holstein Friesian Milchkühen

Abstract. Title of the paper: Relationship between milk yield, fertility and amount of disease of Holstein Friesian dairy cows Data of 1 841 lactations of 353 Holstein Friesian dairy cows and data according to their reproductive fertility and diseases were analysed over a period of five years in a breeding farm in Thüringen (Germany). As a result the lowest success of first service has been achieved at a lactation (ranged) between 9 000 and 11 000 kg. The time between calving and the following first service varied according to the first disease in last lactation. With rising milk yield the frequency of diseases and the success of first service tend to decrease. Cows achieving a 305 day milk yield of more than 11 000 kg showed with 56 % the lowest frequency of diseases. In average 60 % of all dairy cows need to be treated once in a lactation. The diseases of highest prevalence are in the field of reproductive fertility and udder health. For heifers a decreased success of first service has been detected if they showed an increased prevalence of illness.

The influence of Adh function on ethanol preference and tolerance in adult Drosophila melanogaster

Preference determines behavioral choices such as choosing among food sources and mates. One preference-affecting chemical is ethanol, which guides insects to fermenting fruits or leaves. Here, we show that adult Drosophila melanogaster prefer food containing up to 5% ethanol over food without ethanol and avoid food with high levels (23%) of ethanol. Although female and male flies behaved differently at ethanol-containing food sources, there was no sexual dimorphism in the preference for food containing modest ethanol levels. We also investigated whether Drosophila preference, sensitivity and tolerance to ethanol was related to the activity of alcohol dehydrogenase (Adh), the primary ethanol-metabolizing enzyme in D. melanogaster. Impaired Adh function reduced ethanol preference in both D. melanogaster and a related species, D. sechellia. Adh-impaired flies also displayed reduced aversion to high ethanol concentrations, increased sensitivity to the effects of ethanol on postural control, and negative tolerance/sensitization (i.e., a reduction of the increased resistance to ethanol's effects that normally occurs upon repeated exposure). These data strongly indicate a linkage between ethanol-induced behavior and ethanol metabolism in adult fruit flies: Adh deficiency resulted in reduced preference to low ethanol concentrations and reduced aversion to high ones, despite recovery from ethanol being strongly impaired.

Array-CGH and quantitative PCR genetic analysis in a case with bilateral hypoplasia of pulmonary arteries and lungs and simultaneous unilateral renal agenesis

We describe the clinical course and have characterised anatomically and genetically a unique case of a newborn with bilateral hypoplasia of pulmonary arteries, consecutive extremely hypoplastic lung tissue and associated unilateral renal agenesis. Intrauterine oxygenation by the placenta seemed to have allowed normotrophic body maturity but immediately after delivery, in the third trimester, progressive hypoxemia developed and the newborn succumbed to acute respiratory failure. Genetic analysis by array-based comparative genomic hybridisation and quantitative PCR revealed duplication of 1p21, which, however, might not be the disease causing aberration. This case might represent an extreme form of previously reported, rare cases with simultaneous dysorganogenesis of lungs and kidneys.

'Imported' melioidosis in Germany: relapse after 10 years

A 62-year-old German patient with insulin-dependent diabetes and diverticulitis was hospitalized for abdominal pain of the left lower quadrant. Further examination revealed an abdominal abscess, which was punctured. Presumptively a Pseudomonas species was identified, but further examination revealed Burkholderia pseudomallei as the causative agent. Most probably this infection was acquired in 1996 during a trip to Thailand, where the patient had been hospitalized. After combined chemotherapy and surgical revision of the abscess, the patient's condition improved. Clinicians and microbiologists have to keep in mind that in some tropical infections such as melioidosis relapse may occur after such a long time.

Enhanced pulmonary expression of the TrkB neurotrophin receptor in hypoxic rats is associated with increased acetylcholine-induced airway contractility

AIM

We have recently reported that hypoxia stimulates transcription of the TrkB neurotrophin receptor in cultured cells via stabilization of hypoxia-inducible factor-1alpha. Here we investigated whether the expression of TrkB and other neurotrophin receptors is oxygen-sensitive also in vivo, and explored the functional consequences of an oxygen-regulated TrkB expression.

METHODS

Rats were exposed either to 21% O(2) or 8% O(2) for 6 h and TrkB was analysed by reverse transcription real-time PCR, in situ mRNA hybridization, and immunological techniques. The importance of the brain-derived neurotrophic factor (BDNF)-TrkB pathway in the control of mechanical airway function was assessed on isolated tracheal segments from normoxic and hypoxic rats.

RESULTS

TrkB transcripts were increased approx. 15-fold in the lungs of hypoxic rats, and the respiratory epithelium was identified as the site of enhanced TrkB expression in hypoxia. The TrkB ligand, BDNF, significantly increased the contractile response to acetylcholine (ACh) of isolated tracheal segments from hypoxic but not from normoxic rats. This effect of BDNF was prevented by pre-incubation of the tissue specimens with the tyrosine kinase inhibitor K252a and by mechanical removal of the TrkB containing airway epithelium. Likewise, the nitric oxide (NO) synthase inhibitor l-NAME abrogated the influence of BDNF on ACh-induced contractions of isolated tracheal segments from hypoxic rats.

CONCLUSION

These results demonstrate that systemic hypoxia stimulates expression of the TrkB neurotrophin receptor in the airway epithelium. Furthermore, activation of TrkB signalling by BDNF in hypoxia enhances mechanical airway contractility to ACh through a mechanism that requires NO.

The synthetic liver X receptor agonist GW3965 reduces tissue factor production and inflammatory responses in human islets in vitro

AIMS/HYPOTHESIS

Optimising islet culture conditions may be one strategy for reducing islet loss prior to, and immediately after, islet transplantation. Liver X receptor (LXR) agonism has previously been shown to increase insulin release from pancreatic islets and reduce inflammation in leucocytes. Our aim was to investigate whether the synthetic LXR agonist GW3965 could modulate the inflammatory status of human pancreatic islets.

METHODS

Levels of pro-inflammatory cytokines and tissue factor in isolated human islets were determined by TaqMan low density array and/or real-time quantitative RT-PCR (mRNA levels) and enzyme immunoassay (EIA) (protein levels). Islet viability was measured using intracellular ATP content, ADP/ATP ratio, mitochondrial dehydrogenase activity (XTT assay) and insulin secretion in a dynamic glucose-challenge model. Apoptosis was determined by EIA measurement of histone-DNA complexes present in cytoplasm and by assaying caspase-3/-7 activity.

RESULTS

Treatment of LPS-stimulated human islets with the synthetic LXR agonist GW3965 (1 micromol/l) for 24 h reduced mRNA and protein levels of selected pro-inflammatory cytokines (IL-8, monocyte chemotactic protein-1 and tissue factor). Moreover, GW3965 had no adverse effect on insulin secretion, islet viability or apoptosis. No excess of lipid accumulation could be detected with the dosage and exposure time used.

CONCLUSIONS/INTERPRETATION

LXR activation suppresses inflammation in human islets in vitro without adverse effects on islet viability. Short-term moderate activation of LXR prior to islet transplantation may represent a possible strategy for improving post-transplant islet survival.

Mapping quantitative trait Loci for left-sided displacement of the abomasum in German Holstein dairy cows

A whole-genome scan using an affected paternal half-sib design was utilized to detect quantitative trait loci (QTL) for left-sided displaced abomasum (LDA) in German Holsteins. A total of 360 animals from 14 paternal half-sib families were genotyped, for a total of 306 polymorphic microsatellites. For a whole-genome scan, 221 markers were equally distributed over all 29 bovine autosomes, with an average distance of 13.7 cM. For fine-mapping, a total of 85 additional microsatellites were used. We identified genome-wide significant QTL on Bos taurus autosome (BTA) 1 (54.6 to 58.3 cM) and on BTA3 (5.9 cM). Furthermore, 3 chromosome-wide significant QTL were located on bovine chromosomes 21, 23, and 24. In addition, we found 11 QTL that cosegregated in grandsire families but that were not significant in the across-family analysis. These QTL were located on BTA5, 6, 10, 12, 15, 16, 17, 19, 23, and 26. This study is the first report on QTL for LDA and is a first step toward identifying single nucleotide polymorphisms for LDA-QTL.

Anti-angiogenic factors and pre-eclampsia in type 1 diabetic women

AIMS/HYPOTHESIS

Elevated anti-angiogenic factors such as soluble fms-like tyrosine kinase 1 (sFlt1), a soluble form of vascular endothelial growth factor receptor, and endoglin, a co-receptor for TGFbeta1, confer high risk of pre-eclampsia in healthy pregnant women. In this multicentre prospective study, we determined levels of these and related factors in pregnant women with type 1 diabetes, a condition associated with a fourfold increase in pre-eclampsia.

METHODS

Maternal serum sFlt1, endoglin, placental growth factor (PlGF) and pigment epithelial derived factor were measured in 151 type 1 diabetic and 24 healthy non-diabetic women at each trimester and at term.

RESULTS

Approximately 22% of the diabetic women developed pre-eclampsia, primarily after their third trimester visit. In women with pre-eclampsia (diabetic pre-eclampsia, n = 26) vs those without hypertensive complications (diabetic normotensive, n = 95), significant changes in angiogenic factors were observed, predominantly in the early third trimester and prior to clinical manifestation of pre-eclampsia. Serum sFlt1 levels were increased approximately twofold in type 1 diabetic pre-eclampsia vs type 1 diabetic normotensive women at the third trimester visit (p < 0.05) and the normal rise of PlGF during pregnancy was blunted (p < 0.05). Among type 1 diabetic women, third trimester sFlt1 and PlGF were inversely related (r(2) = 42%, p < 0.0001). Endoglin levels were increased significantly in the diabetic group as a whole vs the non-diabetic group (p < 0.0001).

CONCLUSIONS/INTERPRETATION

Higher sFlt1 levels, a blunted PlGF rise and an elevated sFlt1/PlGF ratio are predictive of pre-eclampsia in pregnant women with type 1 diabetes. Elevated endoglin levels in women with type 1 diabetes may confer a predisposition to pre-eclampsia and may contribute to the high incidence of pre-eclampsia in this patient group.

Intoxicated fly brains: neurons mediating ethanol-induced behaviors

In free nature, animals rarely become alcoholics. Only when humans interfere do they develop some aspects of dependence. In humans, it is thought that 40-60% of the risk to become an alcoholic is influenced by genetic factors. The interplay between the genetic predisposition and the environment is thought to promote addictive behaviors to ethanol (Schuckit, 2000). Animal models are widely used to functionally dissect behaviors that are associated with alcohol dependence and to characterize the related ethanol responsive genes (Lovinger & Crabbe, 2005). Thus, brain regions and neurons have been identified that mediate ethanol-induced behaviors (Rothenfluh & Heberlein, 2002). This review aims to give an overview of ethanol-induced behaviors and the correlating neurons/neuronal structures in Drosophila melanogaster mediating these behaviors and discusses the possible significance of these results.