Perforin Promotes Amyloid Beta Internalisation in Neurons

Studies on the mechanisms of neuronal amyloid-β (Aβ) internalisation are crucial for understanding the neuropathological progression of Alzheimer’s disease (AD). We here investigated how extracellular Aβ peptides are internalised and focused on three different pathways: (i) via endocytic mechanisms, (ii) via the receptor for advanced glycation end products (RAGE) and (iii) via the pore-forming protein perforin. Both Aβ₄₀ and Aβ₄₂ were internalised in retinoic acid differentiated neuroblastoma (RA-SH-SY5Y) cells. A higher concentration was required for Aβ₄₀ (250 nM) compared with Aβ₄₂ (100 nM). The internalised Aβ₄₀ showed a dot-like pattern of distribution whereas Aβ₄₂ accumulated in larger and distinct formations. By confocal microscopy, we showed that Aβ₄₀ and Aβ₄₂ co-localised with mitochondria, endoplasmic reticulum (ER) and lysosomes. Aβ treatment of human primary cortical neurons (hPCN) confirmed our findings in RA-SH-SY5Y cells, but hPCN were less sensitive to Aβ; therefore, a 20 (Aβ₄₀) and 50 (Aβ₄₂) times higher concentration was needed for inducing uptake. The blocking of endocytosis completely inhibited the internalisation of Aβ peptides in RA-SH-SY5Y cells and hPCN, indicating that this is a major pathway by which Aβ enters the cells. In addition, the internalisation of Aβ₄₂, but not Aβ₄₀, was reduced by 55 % by blocking RAGE. Finally, for the first time we showed that pore formation in cell membranes by perforin led to Aβ internalisation in hPCN. Understanding how Aβ is internalised sheds light on the pathological role of Aβ and provides further ideas of inhibitory strategies for preventing Aβ internalisation and the spreading of neurodegeneration in AD.     

Therapeutic efficacy in BALB/C mice of extract from marine alga <Emphasis Type="Italic">Canistrocarpus cervicornis</Emphasis> (Phaeophyceae) against herpes simplex virus type 1

Studies with diterpenes from marine brown alga Canistrocarpus cervicornis showed the antiviral potential of the products from this alga in controlling the replication of HSV-1 and maintaining low cytotoxicity. Hence, the aim of this work was to evaluate the anti-herpetic efficacy of C. cervicornis extract ointment in BALB/c mice. To test the anti-herpetic efficacy in vivo, four groups of BALB/c mice (n?=?5) were used: 1—untreated, 2—extract ointment (2 % or 0.4 mg cm^?2 dose^?1), 3—Acyclovir cream (5 % or 1.0 mg cm^?2 dose^?1), and 4—ointment base. The right midflank of each mouse was clipped and depilated with a chemical depilatory. After 2 days, the skin area was scratched and inoculated with HSV-1. The ointments and cream were applied three times a day over a 16-day period, beginning 1 h after virus inoculation. The development of skin lesions was continuously monitored and scored. To evaluate the effect of C. cervicornis topical treatment on biochemical parameters and on body weight, two uninfected groups were formed: an untreated group and a group treated with ointment C. cervicornis extract (2 %). The signs of infection appeared from the second day after infection, while on the 10th day of the experiment, the ointment base and untreated groups had significantly more severe lesions than did the groups that were treated with extract (p?<?0.05) or acyclovir (p?<?0,01). The topical application of extract ointment did not change body weight, hepatic, or renal function suggesting that the extract has a low toxicity in this route of administration. These results suggest that the extract may be useful in reducing the severity of HSV-1 cutaneous lesions.     

Carbohydrate uptake in Advenella mimigardefordensis strain DPN7T is mediated by periplasmic sugar oxidation and a TRAP‐transport system

In this study, we investigated an SBP (DctP_Am) of a tripartite ATP‐independent periplasmic transport system (TRAP) in Advenella mimigardefordensis strain DPN7^T. Deletion of dctP_Am as well as of the two transmembrane compounds of the tripartite transporter, dctQ and dctM, impaired growth of A. mimigardefordensis strain DPN7^T, if cultivated on mineral salt medium supplemented with d ‐glucose, d ‐galactose, l ‐arabinose, d ‐fucose, d ‐xylose or d ‐gluconic acid, respectively. The wild type phenotype was restored during complementation studies of A. mimigardefordensis ΔdctP_Am using the broad host vector pBBR1MCS‐5::dctP_Am. Furthermore, an uptake assay with radiolabeled [¹⁴C(U)]‐d ‐glucose clearly showed that the deletion of dctP_Am, dctQ and dctM, respectively, disabled the uptake of this aldoses in cells of either mutant strain. Determination of K_D performing thermal shift assays showed a shift in the melting temperature of DctP_Am in the presence of d ‐gluconic acid (K_D 11.76 ± 1.3 µM) and the corresponding aldonic acids to the above‐mentioned carbohydrates d ‐galactonate (K_D 10.72 ± 1.4 µM), d ‐fuconic acid (K_D 13.50 ± 1.6 µM) and d ‐xylonic acid (K_D 8.44 ± 1.0 µM). The sugar (glucose) dehydrogenase activity (E.C.1.1.5.2) in the membrane fraction was shown for all relevant sugars, proving oxidation of the molecules in the periplasm, prior to transport.     

The effects of paternal reproductive tactic and rearing environment on juvenile variation in growth as mediated through aggression and foraging behaviours of Chinook salmon (Oncorhynchus tshawytscha)

In species with indeterminate growth, differential growth rates can lead to animals adopting alternative reproductive tactics such as sneak–guard phenotypes, which is partially predicted by variation in growth during the juvenile life‐history stage. To investigate sources of growth variation, we examined the independent and joint effects of paternal reproductive tactic (G) and rearing environment (E) on juvenile growth in Chinook salmon (Oncorhynchus tshawytscha), hypothesizing G and E effects are partially mediated through differences in behaviour such as aggressive interactions and resulting foraging behaviours. We created maternal half‐sibling families with one‐half of the female's eggs fertilized by the milt of a sneaker “jack” and the other half by a guarder “hooknose”. At the exogenous feeding stage, each split‐clutch family was then divided again and reared in a rationed diet or growth‐promotion diet environment for approximately 6 months, during which growth parameters were measured. Before saltwater transfer at 9 months of age, social interactions were observed in groups of six fish of various competitor origins. We found ration restricts growth rate and juvenile mass, and evidence of genetic effects on growth depensation, where jack‐sired individuals grew less uniformly over time. These growth‐related differences influenced an individual's level of aggression, with individuals raised on a restricted diet and those whose families experienced greatest growth being most aggressive. These individuals were more likely to feed than not and feed most often. Jack‐sired individuals were additionally aggressive in the absence of food, and when raised on a rationed diet outcompeted others to feed most. These results show how individuals may achieve higher growth rates via intrinsic (G) or induced (E) aggressive behavioural phenotypes, and eventually attain the threshold body size necessary during the saltwater phase to precociously sexually mature and adopt alternative reproductive phenotypes.     

Patterns of sorafenib and TACE treatment of unresectable hepatocellular carcinoma in a Chinese population: subgroup analysis of the GIDEON study

To analyze safety and efficacy of patterns of sorafenib and TACE therapy under real-life clinical practice conditions. A total of 338 Chinese patients with unresectable hepatocellular carcinoma (HCC) from the international database of the GIDEON non-interventional trial were included in this analysis. Endpoints were overall survival (OS), progression-free survival (PFS), time to progression (TTP) and safety. Two major patterns in the use of sorafenib observed in current Chinese clinical practice were: sorafenib administration subsequent to transarterial chemoembolization (TACE) treatment (n?=?226, 66.9%) and sorafenib administration concomitant to TACE (n?=?80, 35.4%). Patients receiving TACE prior to sorafenib had worse liver function (43.8% BCLC stage Cat diagnosis and 62.1% BCLC stage C at study entry) than those receiving TACE concomitant to sorefenib (35.0% BCLC stage C at diagnosis and 51.3% BCLC stage three at study entry). For patients undergoing prior TACE and concomitant TACE treatment, median OS time was 354 days vs. 608 days, PFS time was 168 days vs. 201 days, and TTP was 214 days vs. 205 days; and the percentage of patients who experienced drug-related adverse effects after sorafenib therapy in these two groups were 33.3 and 50.0%, respectively. Sorafenib treatment is usually administered in cases of tumor progression or poor liver function status after TACE treatment in China. Under such conditions, patients still gained a relatively satisfactory survival outcome. In addition, the present study suggests that concomitant sorafenib and TACE treatments may lead to a better prognosis, although differences in baseline characteristics may have contributed in part to the better outcomes.     

Genetic variation in the Red-Listed moss Ditrichum cornubicum Paton (Ditrichaceae) and implications for its conservation

Ditrichum cornubicum is a rare and threatened acrocarpous moss found on copper-rich mine waste, characteristic of the EU protected habitat ‘Calaminarian grassland of the Violetalia calaminariae’. The species was once thought to be a British endemic, being known from two former copper/tin mine sites in Cornwall, until the discovery of a population in 2006 at Allihies Mountain Mine, Co. Cork, Ireland, a former copper mine. In light of this discovery, two theories of possible introduction from Britain to Ireland were put forward: (1) an introduction from the 1800s and (2) a more recent introduction (2000s). Only male plants of the species are known, and reproduction and dispersal are therefore solely through asexual propagules and fragmentation. In order to address the conservation questions of the origin of the Irish population and to determine whether diversity exists within this rare species, genetic fingerprinting (amplified fragment length polymorphism) was carried out on the three known global populations. Percent polymorphism was found to be 7.29% and Nei's total gene diversity (H_T) was 0.0356. AMOVA revealed that, of the small amount of variation found, the majority was among the three populations (98%). The presence of five private alleles in the Allihies population suggests a longer period of isolation than would fit either theory of introduction. Cluster analyses reveal that the Allihies population is more genetically distinct than the two British populations are to each other, thus heightening the conservation priority for this population.     

Sleeping site ecology,but not sex,affect ecto- and hemoparasite risk,in sympatric,arboreal primates (<Emphasis Type="Italic">Avahi occidentalis</Emphasis> and <Emphasis Type="Italic">Lepilemur edwardsi</Emphasis>)

Background

A central question in evolutionary parasitology is to what extent ecology impacts patterns of parasitism in wild host populations. In this study, we aim to disentangle factors influencing the risk of parasite exposure by exploring the impact of sleeping site ecology on infection with ectoparasites and vector-borne hemoparasites in two sympatric primates endemic to Madagascar. Both species live in the same dry deciduous forest of northwestern Madagascar and cope with the same climatic constraints, they are arboreal, nocturnal, cat-sized and pair-living but differ prominently in sleeping site ecology. The Western woolly lemur (Avahi occidentalis) sleeps on open branches and frequently changes sleeping sites, whereas the Milne-Edward’s sportive lemur (Lepilemur edwardsi) uses tree holes, displaying strong sleeping site fidelity. Sleeping in tree holes should confer protection from mosquito-borne hemoparasites, but should enhance the risk for ectoparasite infestation with mites and nest-adapted ticks. Sex may affect parasite risk in both species comparably, with males bearing a higher risk than females due to an immunosuppressive effect of higher testosterone levels in males or to sex-specific behavior. To explore these hypotheses, ectoparasites and blood samples were collected from 22 individuals of A. occidentalis and 26 individuals of L. edwardsi during the dry and rainy season.

Results

L. edwardsi, but not A. occidentalis, harbored ectoparasites, namely ticks (Haemaphysalis lemuris [Ixodidae], Ornithodoros sp. [Argasidae]) and mites (Aetholaelaps trilyssa, [Laelapidae]), suggesting that sleeping in tree holes promotes infestation with ectoparasites. Interestingly, ectoparasites were found solely in the hot, rainy season with a prevalence of 75% (N = 16 animals). Blood smears were screened for the presence and infection intensity of hemoparasites. Microfilariae were detected in both species. Morphological characteristics suggested that each lemur species harbored two different filarial species. Prevalence of microfilarial infection was significantly lower in L. edwardsi than in A. occidentalis. No significant difference in infection intensity between the two host species, and no effect of season, daytime of sampling or sex on prevalence or infection intensity was found. In neither host species, parasite infection showed an influence on body weight as an indicator for body condition.

Conclusions

Our findings support that sleeping site ecology affects ectoparasite infestation in nocturnal, arboreal mammalian hosts in the tropics, whereas there is no significant effect of host sex. The influence of sleeping site ecology to vector-borne hemoparasite risk is less pronounced. The observed parasite infections did not affect body condition and thus may be of minor importance for shaping reproductive fitness. Findings provide first evidence for the specific relevance of sleeping site ecology on parasitism in arboreal and social mammals. Further, our results increase the sparse knowledge on ecological drivers of primate host-parasite interactions and transmission pathways in natural tropical environments.

     

Predator and prey: the role of the round goby Neogobius melanostomus in the western Baltic

Different studies on the position of the non-indigenous species Neogobius melanostomus within the coastal food web of the Pomeranian Bay (western Baltic) were performed, resulting in a quantitative and qualitative species list of prey organisms found in the stomachs of the invader and an estimation concerning the importance of round goby as prey for different resident predators. It seems that the colonization process is not fully completed yet, but the results reveal that the species is already established in the food web 16 years after the first observation within the study area. The results show that N. melanostomus feed upon a wide range of different resident organisms. While a direct predation effect on native fish species appears rather unlikely, indirect effects such as competition cannot yet be excluded. In addition, our results reveal an ontogenetic diet shift and that the round goby itself already serves as an important prey for piscivorous fish and seabirds. Finally, we formulate different hypotheses based on our results which will require further research.     

Intracoronary allogeneic cardiosphere‐derived stem cells are safe for use in dogs with dilated cardiomyopathy

Cardiosphere‐derived cells (CDCs) have been shown to reduce scar size and increase viable myocardium in human patients with mild/moderate myocardial infarction. Studies in rodent models suggest that CDC therapy may confer therapeutic benefits in patients with non‐ischaemic dilated cardiomyopathy (DCM). We sought to determine the safety and efficacy of allogeneic CDC in a large animal (canine) model of spontaneous DCM. Canine CDCs (cCDCs) were grown from a donor dog heart. Similar to human CDCs, cCDCs express CD105 and are slightly positive for c‐kit and CD90. Thirty million of allogeneic cCDCs was infused into the coronary vessels of Doberman pinscher dogs with spontaneous DCM. Adverse events were closely monitored, and cardiac functions were measured by echocardiography. No adverse events occurred during and after cell infusion. Histology on dog hearts (after natural death) revealed no sign of immune rejection from the transplanted cells.