Creating conditions for changes in prey community structure by Chaoborus spp. in a lake in Sweden

In Lake G»rdsjön (Southwest Sweden), liming as an experimental improvement of living conditions for pelagic algae, resulted in a significant increase of algal biomass and a reduction of mean cell size. The algal development was beneficial for small sized filter feeding zooplankton, particularly rotifers, which showed a significant increase. The increase in abundance of small sized zooplankton created better food conditions for the smaller instars, and thus a much better overall survival of Chaoborus larvae. The resulting, 6–7 times larger population of Chaoborus larvae significantly changed the structure of the crustacean zooplankton community. Bosmina coregoni, the fastest swimmer of the crustacean species suffered most and was strongly reduced by the increased predation from Chaoborus. The share of cladocerans decreased, while copepods increased in importance.     

Alarm substance in Gyrinus aeratus (Coleoptera,Gyrinidae)

Gyrinid beetles are common in ponds and lakes in Sweden, where they aggregate in open areas of the surface. Gyrinid beetles have pygidial glands which produce compounds rendering them unpalatable to fish. This study examines whether the pygidial secretion can be used for alarm purposes in addition to other functions. Experiments showed that gyrinid beetles responded to water prepared with the pygidial compounds by evasive behaviour. The beetles did not respond when the compound was mediated by air. One component of the defense system of gyrinids is how they advertise their presence. The aggregation of dark beetles with their typical motion pattern when alerted is very conspicuous and easily identified by an experienced predator. We suggest that this aspect of gyrinid defence can be characterized as aposematic.     

Klinik und Genetik des familiären Darmkrebses

Familial clustering of colorectal cancer (CRC) and early disease onset are indicators of an inherited tumour syndrome. Monogenic dispositions account for 3–5% of all CRC cases and are subdivided into hereditary non-polyposis colorectal cancer (HNPCC/Lynch syndrome) and various gastrointestinal polyposis syndromes. Many of these syndromes are characterised by a broad spectrum of extracolonic tumours. Early detection and accurate classification are essential in providing effective surveillance and treatment. Initial diagnosis is based on endoscopic and histological findings as well as on the presence of extracolonic manifestations and family history. Molecular genetic examination is important for the differential diagnosis, evaluation of recurrence risk, and predictive testing of asymptomatic at risk individuals; it is performed according to largely standardised algorithms. Diagnostic difficulties are common among the hamartomatous polyposes due to their broad phenotypic overlap and frequent uncertainties in histological evaluation, as well as among patients with few adenomas. Risk-adapted surveillance guidelines have been established for HNPCC and for the more frequently observed polyposis syndromes. Beyond established tumour syndromes, familial clustering of CRC (which is often of late onset) or the occurrence of few adenomas is likely to be based upon a multifactorial (complex) etiology. Although identification of the underlying genetic risk factors and biological pathways is still in the early stages, rapid progress is being made due to methodical developments such as genome-wide association studies and CNV analysis.     

Expression and regulation of cyclic nucleotide phosphodiesterases in human and rat pancreatic islets

As shown by transgenic mouse models and by using phosphodiesterase 3 (PDE3) inhibitors, PDE3B has an important role in the regulation of insulin secretion in pancreatic β-cells. However, very little is known about the regulation of the enzyme. Here, we show that PDE3B is activated in response to high glucose, insulin and cAMP elevation in rat pancreatic islets and INS-1 (832/13) cells. Activation by glucose was not affected by the presence of diazoxide. PDE3B activation was coupled to an increase as well as a decrease in total phosphorylation of the enzyme. In addition to PDE3B, several other PDEs were detected in human pancreatic islets: PDE1, PDE3, PDE4C, PDE7A, PDE8A and PDE10A. We conclude that PDE3B is activated in response to agents relevant for β-cell function and that activation is linked to increased as well as decreased phosphorylation of the enzyme. Moreover, we conclude that several PDEs are present in human pancreatic islets.     

Botanische Gärten in der Zeit des Kolonialismus. Auf der Jagd nach dem “Grünen Gold”

Plant Transfer and Botanical Gardens in Colonial Times A constant of economic history is the need of natural resources – in the past often of vegetable origin and available only from the countries of natural distribution. These countries often tried to protect their interests against the traders or users by declaring monopoles. Between these both poles botanic gardens acted very successfully and by far not according to modern ethic standards. Results of their activities were the transcontinental movements of plants and the initiation of new agricultural based industries. These should be exemplified by the British botanical gardens and species as tea shrub, rubber tree, and cinchona tree.     

Fueling phocids: Divergent exploitation of primary energy sources and parallel ontogenetic diet switches among three species of subarctic seals

Determining how marine predators partition resources is hindered by the difficulty in obtaining information on diet and distribution. Stable isotopes (SI) of carbon (¹³C/¹²C, δ¹³C) and nitrogen (¹⁵N/¹⁴N, δ¹⁵N) provide a two‐dimensional estimate of the dietary space of consumers; an animal's isotopic composition is directly influenced by what they consume and where they feed. Harp (Pagophilus groenlandicus) and hooded (Cystophora cristata) seals are abundant phocid species found in the North Atlantic. We measured and contrasted SI values between seals sampled at nearshore and offshore sites to test for effects of sampling location, sex, age‐class, and body size to gain insight into how these species partition space and prey resources. In addition we contrasted previously published results for gray seals (Halichoerus grypus). Isotope values differed significantly by age class and location in harp and hooded seals. We found significant differences in SI values (mean δ¹³C and δ¹⁵N ± SE) between all species. Hooded seals, a continental shelf‐edge, deep‐diving species, exhibited low SI values (juveniles: ?20.9‰ ± 0.03‰, 13.36‰ ± 0.05‰; adults: ?20.41‰ ± 0.03‰, 14.81‰ ± 0.04‰) characteristic of feeding on meso‐ to bathypelagic prey. Harp seals, which dive to moderate depths primarily on the shelf had intermediate SI values (juveniles: ?20.53‰ ± 0.01‰, 13.91‰ ± 0.01‰; adults: ?20.13‰ ± 0.01‰, 14.96‰ ± 0.01‰) characteristic of feeding on epipelagic prey, whereas gray seals, which feed on or near the sea floor in shallow shelf waters, had high SI values (juveniles: ?19.74‰ ± 0.04‰, 17.51‰ ± 0.05‰; adults: ?18.86‰ ± 0.01‰, 17.23‰ ± 0.02‰) characteristic of feeding on demersal prey. In all species, δ¹³C values increased with body size and age in the same manner, indicating that seals exploit or forage in deeper habitats as they get larger and older. We hypothesize that the consistent ontogenetic shift in foraging niche, despite large differences between species in their diving behavior, geographic range and habitat use, not only reflects increased access to different prey due to increased diving capacity, but a progressive adjustment to balance energy budgets by reducing foraging costs.     

Mosaike bei monogenen Erkrankungen

Mosaicism is defined as the simultaneous presence of cells with different genotypes that originate from a common zygote. Mutations can either be present in germline or somatic cells. Monogenic disorders apparently caused by a de novo mutation may show a recurrence risk due to germline mosaicism in a parent. Duchenne muscular dystrophy is a well investigated example with a high frequency of germline mosaicism and the estimation for the risk of recurrence is based on theoretical models and empirical data. Recently, somatic mutations have been uncovered in various syndromic disorders, such as Proteus syndrome or hemimegalencephaly and respective mutations often show gain-of-function properties. Genetic testing is mainly based on next generation sequencing technologies but still remains challenging; however, detection of somatic mosaicism is expected to be of increasing relevance in the diagnosis of monogenic disorders. Somatic mosaicism may also play a hitherto underestimated role in common disorders.     

Chemical cues from the invertebrate predator Leptodora kindtii affect the development of cyclomorphic traits in Eubosmina coregoni gibbera

The induction of two cyclomorphic traits, antennule length andcarapace height, in Eubosmina coregoni gibbera by the cladoceranpredator Leptodora kindtii was investigated in an experimentalstudy. It was found that both carapace height and antennulelength were significantly larger when the predator cues werepresent. However, antennule length only differed in adults,while juveniles showed no difference in antennule length betweenthe treatments. Our results indicate that morphological anti-predatortraits can reduce the vulnerability of adults, whereas the smallsize of juveniles may prevent the anti-predator traits frombeing effective.