Regulierung und Schattenwirtschaft

Die Bedeutung der Steuer- und Abgabenlast für die Entwicklung der Schattenwirtschaft wurde bereits in vielen Studien untersucht. Schwieriger gestaltete sich bislang aufgrund fehlender Daten die systematische empirische Überprüfung des Zusammenhangs zwischen Regulierungen und Schattenwirtschaft. Auf Basis des IWRegulierungsindexes kann nun erstmals der Einfluss von Regulierungen auf die Schattenwirtschaft umfassend ermittelt werden. Dieser Zusammenhang ist sehr stark und bleibt auch bei der Einbeziehung weiterer Faktoren wie Steuer- und Abgabenlast robust. Auf dieser Basis lässt sich unter anderem errechnen, dass in Deutschland bis zu 500.000 Arbeitsplätze legalisiert werden könnten, wenn die Regulierungsdichte auf das angelsächsische Niveau abgesenkt würde

Effects of low seawater pH on the marine polychaete Platynereis dumerilii

An important priority for any organism is to maintain internal cellular homeostasis including acidbase balance. Yet, the molecular level impacts of changing environmental conditions, such as low pH, remain uncharacterised. Herein, we isolate partial Na+/H+ exchangers (NHE), carbonic anhydrase (CA), and calmodulin (CaM) genes from a polychaete, Platynereis dumerilii and investigate their relative expression in acidified seawater conditions. mRNA expression of NHE was significantly down-regulated after 1 h and up-regulated after 7 days under low pH treatment (pH 7.8), indicating changes in acid-base transport. Furthermore, the localisation of NHE expression was also altered. A trend of down regulation in CA after 1 h was also observed, suggesting a shift in the CO2 and HCO3- balance. No change in CaM expression was detected after 7 days exposure to acidified seawater. This study provides insight into the molecular level changes taking place following exposure to acidified seawater in a non-calcifying, ubiquitous, organism

Exposure to low pH induces molecular level changes in the marine worm, Platynereis dumerilii

© 2015 Elsevier Inc. Fossil fuel emissions and changes in net land use lead to an increase in atmospheric CO 2 concentration and a subsequent decrease of ocean pH. Noticeable effects on organisms' calcification rate, shell structure and energy metabolism have been reported in the literature. To date, little is known about the molecular mechanisms altered under low pH exposure, especially in non-calcifying organisms. We used a suppression subtractive hybridisation (SSH) approach to characterise differentially expressed genes isolated from Platynereis dumerilii, a non-calcifying marine polychaeta species, kept at normal and low pH conditions. Several gene sequences have been identified as differentially regulated. These are involved in processes previously considered as indicators of environment change, such as energy metabolism (NADH dehydrogenase, 2-oxoglutarate dehydrogenase, cytochrome c oxidase and ATP synthase subunit F), while others are involved in cytoskeleton function (paramyosin and calponin) and immune defence (fucolectin-1 and paneth cell-specific alpha-defensin) processes. This is the first study of differential gene expression in a non-calcifying, marine polychaete exposed to low pH seawater conditions and suggests that mechanisms of impact may include additional pathways not previously identified as impacted by low pH in other species

Simultaneously hermaphroditic shrimp use lipophilic cuticular hydrocarbons as contact sex pheromones

Successful mating is essentially a consequence of making the right choices at the correct time. Animals use specific strategies to gain information about a potential mate, which is then applied to decision-making processes. Amongst the many informative signals, odor cues such as sex pheromones play important ecological roles in coordinating mating behavior, enabling mate and kin recognition, qualifying mate choice, and preventing gene exchange among individuals from different populations and species. Despite overwhelming behavioral evidence, the chemical identity of most cues used in aquatic organisms remains unknown and their impact and omnipresence have not been fully recognized. In many crustaceans, including lobsters and shrimps, reproduction happens through a cascade of events ranging from initial attraction to formation of a mating pair eventually leading to mating. We examined the hypothesis that contact pheromones on the female body surface of the hermaphroditic shrimp Lysmata boggessi are of lipophilic nature, and resemble insect cuticular hydrocarbon contact cues. Via chemical analyses and behavioural assays, we show that newly molted euhermaphrodite-phase shrimp contain a bouquet of odor compounds. Of these, (Z)-9-octadecenamide is the key odor with hexadecanamide and methyl linoleate enhancing the bioactivity of the pheromone blend. Our results show that in aquatic systems lipophilic, cuticular hydrocarbon contact sex pheromones exist; this raises questions on how hydrocarbon contact signals evolved and how widespread these are in the marine environment

Short-term effects of CO₂-induced low pH exposure on target gene expression in Platynereis dumerilii

Objective: Increasing atmospheric CO₂ concentration are causing changes to the seawater carbonate chemistry, lowering the pH and we study potential impacts of these changes at the molecular level in a non-calcifying, marine polychaete species Platynereis dumerilii. Methods: we investigate the relative expression of carbonic anhydrase (CA), Na+/H+ exchangers (NHE), and calmodulin (CaM) genes from P. dumerilii under acidified seawater conditions (pH 7.8) induced by CO₂ using qPCR. Results: mRNA expression of CA in the CO₂-induced worms was significantly up-regulated at low pH conditions (pH 7.8, 1h), suggesting changes in acid-base balance. In contrast, the expression of NHE and CaM showed no significant change. In addition, we compare these results to a previous study using inorganic acid (HCl)-induced pH changes. Conclusions: results suggest that carbonate chemistry has an impact on gene expression that differs from pH-associated change. To our knowledge, this is the first study that compares low pH exposure experiments using HCl and CO₂ as the inducing agents

Reproductive isolation between two sympatric simultaneous hermaphroditic shrimp, Lysmata wurdemanni and L. boggessi

To investigate pre- and post-zygotic isolation between two sympatric and phylogenetically related species of Lysmata shrimp, two assays were conducted in the laboratory: (1) no specific mate choice where mating between the two species was ‘forced’; (2) specific mate choice or preference where a female had a choice between conspecific and heterospecifc males. Behavioural studies reveal that female L. wurdemanni accepted only conspecific male shrimp, whereas L. boggessi females would mate with an interspecific male if there was no conspecific male present. When males of both species were present, L. boggessi females always mated with the conspecific male. Male L. boggessi in general did not respond to the sex pheromones secreted by female L. wurdemanni and did not display any pre-copulatory behaviour to newly moulted female L. wurdemanni. On the other hand, some male L. wurdemanni responded to female L. boggessi. Although mating was successful between male L. wurdemanni and female L. boggessi, the resulting embryos lived at most for 10 days and failed to hatch. The results indicate that the two species are both pre-zygotically and post-zygotically isolated. Behavioural observation suggests that chemical cues are most likely responsible for pre-zygotic isolation

Experience matters: Females use smell to select experienced males for paternal care

Mate choice and mating preferences often rely on the information content of signals exchanged between potential partners. In species where a female's reproduction is the terminal event in life it is to be expected that females choose high quality males and assess males using some honest indicator of male quality. The Nereidid polychaete, Neanthes acuminata, exhibits monogamous pairing and the release of eggs by females terminates her life and larval success relies entirely on a male's ability to provide paternal care. As such females should have developed reliable, condition-dependent criteria to choose mates to guarantee survival and care for offspring. We show that females actively chose males experienced in fatherhood over others. In the absence of experienced males dominance, as evident from male-male fights, is utilized for mate selection. The preference for experienced males is not affected by previous social interactions between the individuals. We show that the choice of the partner is based on chemical signals demonstrating a 'scent of experience' to females providing evidence for the role of chemical signals in sexual selection for paternal care adding to our understanding of the mechanisms regulating condition-dependent mate choice

Adaptation and acclimatization to ocean acidification in marine ectotherms: an in situ transplant experiment with polychaetes at a shallow CO₂ vent system

Metabolic rate determines the physiological and life-history performances of ectotherms. Thus, the extent to which such rates are sensitive and plastic to environmental perturbation is central to an organism's ability to function in a changing environment. Little is known of long-term metabolic plasticity and potential for metabolic adaptation in marine ectotherms exposed to elevated pCO₂. Consequently, we carried out a series of in situ transplant experiments using a number of tolerant and sensitive polychaete species living around a natural CO₂ vent system. Here, we show that a marine metazoan (i.e. Platynereis dumerilii) was able to adapt to chronic and elevated levels of pCO₂. The vent population of P. dumerilii was physiologically and genetically different from nearby populations that experience low pCO₂, as well as smaller in body size. By contrast, different populations of Amphiglena mediterranea showed marked physiological plasticity indicating that adaptation or acclimatization are both viable strategies for the successful colonization of elevated pCO₂ environments. In addition, sensitive species showed either a reduced or increased metabolism when exposed acutely to elevated pCO₂. Our findings may help explain, from a metabolic perspective, the occurrence of past mass extinction, as well as shed light on alternative pathways of resilience in species facing ongoing ocean acidification

Regulierung, Arbeitsplatzsicherheit und Wohlbefinden

Zur Beurteilung der individuellen Wohlfahrt wird oftmals auf Einkommensgrößen zurückgegriffen. Nichtmonetäre Bestimmungsgründe des subjektiven Wohlbefindens bleiben dabei außen vor. Diese Lücke sollen Befragungen zur Lebenszufriedenheit schließen, die von Faktoren wie Gesundheit, soziale Beziehungen und auch der empfundenen Arbeitsplatzsicherheit beeinflusst wird. Ein internationaler Vergleich zeigt, dass in Deutschland die Arbeitsplatzsicherheit als geringer empfunden wird als in fast allen untersuchten europäischen Ländern – obwohl über staatliche Regulierungsmaßnahmen der deutsche Gesetzgeber versucht, diese Sicherheit zu erhöhen. Höhere Regulierung trägt entgegen der Intention jedoch nicht zu mehr Arbeitsplatzsicherheit bei, sondern wirkt diesem subjektiven Sicherheitsempfinden eher entgegen. Wichtig für die subjektive Arbeitsplatzsicherheit erweisen sich in einem Ländervergleich die generelle Arbeitsmarktsituation und das individuelle Qualifikationsniveau

Targeted disruption of the Kcnj5 gene in the female mouse lowers aldosterone levels.

Aldosterone is released from adrenal zona glomerulosa (ZG) cells and plays an important role in Na and K homoeostasis. Mutations in the human inwardly rectifying K channel CNJ type (KCNJ) 5 (KCNJ5) gene encoding the G-coupled inwardly rectifying K channel 4 (GIRK4) cause abnormal aldosterone secretion and hypertension. To better understand the role of wild-type (WT) GIRK4 in regulating aldosterone release, we have looked at aldosterone secretion in a Kcnj5 knockout (KO) mouse. We found that female but not male KO mice have reduced aldosterone levels compared with WT female controls, but higher levels of aldosterone after angiotensin II (Ang-II) stimulation. These differences could not be explained by sex differences in aldosterone synthase (Cyp11B2) gene expression in the mouse adrenal. Using RNAseq analysis to compare WT and KO adrenals, we showed that females also have a much larger set of differentially expressed adrenal genes than males (395 compared with 7). Ingenuity Pathway Analysis (IPA) of this gene set suggested that peroxisome proliferator activated receptor (PPAR) nuclear receptors regulated aldosterone production and altered signalling in the female KO mouse, which could explain the reduced aldosterone secretion. We tested this hypothesis in H295R adrenal cells and showed that the selective PPARα agonist fenofibrate can stimulate aldosterone production and induce Cyp11b2. Dosing mice in vivo produced similar results. Together our data show that Kcnj5 is important for baseline aldosterone secretion, but its importance is sex-limited at least in the mouse. It also highlights a novel regulatory pathway for aldosterone secretion through PPARα that may have translational potential in human hyperaldosteronism