The photosensor protein Ppr of <Emphasis Type="Italic">Rhodocista centenaria</Emphasis> is linked to the chemotaxis signalling pathway

Background  

Rhodocista centenaria is a phototrophic α-proteobacterium exhibiting a phototactic behaviour visible as colony movement on agar plates directed to red light. As many phototrophic purple bacteria R. centenaria possesses a soluble photoactive yellow protein (Pyp). It exists as a long fusion protein, designated Ppr, consisting of three domains, the Pyp domain, a putative bilin binding domain (Bbd) and a histidine kinase domain (Pph). The Ppr protein is involved in the regulation of polyketide synthesis but it is still unclear, how this is connected to phototaxis and chemotaxis.     

A revision of <Emphasis Type="Italic">Gastrodia</Emphasis> (Orchidaceae: Epidendroideae,Gastrodieae) in tropical Africa

The holomycotrophic terrestrial orchids of tropical Africa are reassessed. Two new species of Gastrodia from tropical Africa are described, G. rwandensis from Rwanda and G. ballii from south-central Africa. The genus now comprises three species in tropical Africa. A key is provided to distinguish them from Gastrodia africana Kraenzl.     

Lipid biomarkers indicate different ecological niches and trophic relationships of the Arctic hyperiid amphipods Themisto abyssorum and T. libellula

The hyperiid amphipods Themisto libellula and T. abyssorum are important components of Arctic pelagic ecosystems. Both species are carnivorous and prey on mesozooplankton. They represent a substantial food source for marine vertebrates and are a key link between zooplankton secondary production and higher trophic levels. We present data on the total lipid content, lipid class and fatty acid composition of T. libellula and T. abyssorum from northern Fram Strait and the central Arctic Ocean. Both species had moderate to high lipid contents of 14-42% of body dry mass. In T. abyssorum, total lipid content was correlated to body mass, while T. libellula showed sex-related differences in lipid content. Despite their smaller body size, females of T. libellula had higher lipid contents than males. Wax esters represented the major lipid class in both species with 41-43% of total lipid, while triacylglycerols contributed 23-32%. The fatty acid composition was dominated by the long-chain polyunsaturated moieties 20:5(n-3) and 22:6(n-3), short-chain saturated compounds (16:0 and 14:0) and monounsaturated fatty acids of varying length, i.e. 16:1(n-7), 20:1(n-9), 18:1(n-9) and 22:1(n-11). Species-specific and geographic variations in the fatty acid and alcohol patterns were apparently linked to differences in diet and life-cycle. High amounts of the fatty acids and alcohols 20:1(n-9) and 22:1(n-11) in T. libellula indicate predation on herbivorous Calanus copepodids. In addition, elevated levels of 20:5(n-3) in T. libellula indicate a close connection with ice-algal production and the importance of cryo-pelagic coupling processes (i.e. exchange processes between the sea ice and the pelagic communities) for the nutrition of this high-Arctic epipelagic species. In contrast, T. abyssorum is characterised by lower amounts of 20:5(n-3) and its biomarker ratios indicate a higher trophic level. This observation is consistent with the subarctic-boreal origin of T. abyssorum and its occurrence in deeper layers of the Arctic Ocean, where it may feed on omnivorous and/or carnivorous prey.     

A Highlights from MBoC Selection: Insulin-promoted mobilization of GLUT4 from a perinuclear storage site requires RAB10

Insulin controls glucose uptake into muscle and fat cells by inducing a net redistribution of glucose transporter 4 (GLUT4) from intracellular storage to the plasma membrane (PM). The TBC1D4-RAB10 signaling module is required for insulin-stimulated GLUT4 translocation to the PM, although where it intersects GLUT4 traffic was unknown. Here we demonstrate that TBC1D4-RAB10 functions to control GLUT4 mobilization from a trans-Golgi network (TGN) storage compartment, establishing that insulin, in addition to regulating the PM proximal effects of GLUT4-containing vesicles docking to and fusion with the PM, also directly regulates the behavior of GLUT4 deeper within the cell. We also show that GLUT4 is retained in an element/domain of the TGN from which newly synthesized lysosomal proteins are targeted to the late endosomes and the ATP7A copper transporter is translocated to the PM by elevated copper. Insulin does not mobilize ATP7A nor does copper mobilize GLUT4, and RAB10 is not required for copper-elicited ATP7A mobilization. Consequently, GLUT4 intracellular sequestration and mobilization by insulin is achieved, in part, through utilizing a region of the TGN devoted to specialized cargo transport in general rather than being specific for GLUT4. Our results define the GLUT4-containing region of the TGN as a sorting and storage site from which different cargo are mobilized by distinct signals through unique molecular machinery.     

‘One Can Always Say No.’ Enriching the Bioethical Debate on Antisocial Behaviour,Neurobiology and Prevention: Views of Juvenile Delinquents

Genomic and neuro‐scientific research into the causes and course of antisocial behaviour triggers bioethical debate. Often, these new developments are met with reservation, and possible drawbacks and negative side‐effects are pointed out. This article reflects on these scientific developments and the bioethical debate by means of an exploration of the perspectives of one important stakeholder group: juveniles convicted of a serious crime who stay in a juvenile justice institution. The views of juveniles are particularly interesting, as possible applications of current and future scientific findings are considered to be most effective if applied early in life. Based on their statements we come to the following provisional conclusions. Concerns about labelling and stigmatization are recognized and widely shared. Possible effects on one's identity are acknowledged too. Yet, a possible biological underpinning of one's antisocial behaviour is not considered to result in the development of a criminal identity. Nonetheless, psychopharmacological interventions are experienced as endangering one's current self. Concerns regarding the refusal of responsibility and the blaming of one's genes or brain can be put into perspective. Instead, participants emphasize the motive of own choice as underlying their criminal behaviour. Moreover, bioethical debate should pay attention to the role of parents of children at risk and the parent‐child relationship in families at‐risk. We argue that the short‐term and long‐term interests of children at risk, as well as their interests and those of society at large, may conflict. In order to deal appropriately with newly arising dilemmas, a normative framework needs to be developed.     

DNS-Reduplikationsmuster der Somatischen Chromosomen von Cricetus cricetus (L.)

The patterns of terminal DNA synthesis of the autosomes and sex chromosomes of Cricetus cricetus were studied. Characteristic late replicating segments are found on all chromosomes allowing identification of most autosomes. The sex chromosomes of both sexes behave similarly; in the male, half of the X and the entire Y are late replicating and heteropycnotic, in the female, half of one X and the whole of the other X. The isopycnotic part of the X-chromosome comprises about 5% of the haploid female complement.

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Wesentliche Teile der vorliegenden Arbeit werden von Fräulein Dorothee Hepp als Dissertation der Medizinischen Fakultät der Universität Freiburg i. Br. vorgelegt.

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Wir danken Dr. Susumu Ohno für kristiche des Munuskriptes und Fräulein Elke Faisst für ihre bei den experimentellen Arbeiten.     

Laypeople's Risky Decisions in the Climate Change Context: Climate Engineering as a Risk-Defusing Strategy?

This study explores the development of laypeople's preferences for newly emerging climate engineering technology (CE). It examines whether laypeople perceive CE to be an acceptable back-up strategy (plan B) if current efforts to mitigate CO₂ emissions were to fail. This idea is a common justification for CE research in the scientific debate and may significantly influence future public debates. Ninety-eight German participants chose their preferred climate policy strategy in a quasi-realistic scenario. Participants could chose between mitigation and three CE techniques as alternative options. We employed a think-aloud interview technique, which allowed us to trace participants’ informational needs and thought processes. Drawing on Huber's risk management decision theory, the study addressed whether specific CE options are more likely to be accepted if they are mentally represented as a back-up strategy. Results support this assumption, especially for cloud whitening. This result is especially relevant considering the high prevalence of the plan B framing in CE appraisal studies and its implications for public opinion-formation processes.