Denning behaviour of ship rats (Rattus rattus) on Taukihepa,a seabird breeding island

Abstract

Den sites of 14 ship rats (Rattus rattus) were located daily during the rat breeding season on Taukihepa (Big South Cape), a seabird island southwest of Rakiura (Stewart Island). In contrast to other New Zealand studies, no arboreal dens were found. Den sites on Taukihepa were in ferns, under logs, in woodpiles, or underground in sooty shearwater (Puffinusgriseus) breeding burrows. The number of times known den sites used was positively related to the amount of leaf litter and woodpiles near the den sites. Overall, 24% of radio‐tagged rats were sharing den sites on any given day. While there was considerable individual variation in the number of times den sites were used, female rats tended to reuse den sites more than males. Many rats were found in dens alone, but frequently males and females shared. Occasionally two females and one male denned together, as did two females, whereas males never denned with another male.     

Disturbance and Resilience in Tropical American Palm Populations and Communities

We review resilience to natural and anthropogenic disturbance of palm populations and communities in tropical America. Response of palms to disturbance depends on their morphological traits, their reproductive strategies and the impacts of these traits and strategies on phenology and gene flow. Human impact induces changes in genetic structure, increasing endogamy and genetic drift in fragmented populations. Forest fragmentation and harvest of palm organs are well documented whereas effects of intermediate disturbance like selective logging, hunting or fire remain poorly known. We recommend emphasis on long-term experiments and on the use of mechanistic approaches in future research to facilitate integration of available data into a theoretical ecological framework.     

Palm Management in South America

We reviewed information on management of useful palms in South America. We documented management for 96 species, from incidental activities intended to increase populations of wild palms to the inclusion of palms in complex agroforestry systems. Two species, Bactris gasipaes and Parajubaea cocoides, are domesticated. Managed species are remarkably fewer than species used in the region, which suggests that harvesters often disregard the fate of the species they use. The best way of managing palms is to employ harvest methods that do not decimate the populations. Although a variety of harvesting techniques have been documented, overharvest is common, and mismanagement prevails – unnecessary felling of palms in order to harvest leaves or fruits is a widespread practice. Research should focus on assessing production in response to management practices, but eradicating the habit of destructive harvest is an obvious priority. Research on palm management must be combined with actions addressed to all stakeholders of the palm/humans system.     

Heart fatty acid binding protein and Aβ-associated Alzheimer’s neurodegeneration

Background

Epidemiological and molecular findings suggest a relationship between Alzheimer’s disease (AD) and dyslipidemia, although the nature of this association is not well understood.

Results

Using linear mixed effects models, we investigated the relationship between CSF levels of heart fatty acid binding protein (HFABP), a lipid binding protein involved with fatty acid metabolism and lipid transport, amyloid-β (Aβ), phospho-tau, and longitudinal MRI-based measures of brain atrophy among 295 non-demented and demented older individuals. Across all participants, we found a significant association of CSF HFABP with longitudinal atrophy of the entorhinal cortex and other AD-vulnerable neuroanatomic regions. However, we found that the relationship between CSF HABP and brain atrophy was significant only among those with low CSF Aβ_1–42 and occurred irrespective of phospho-tau_181p status.

Conclusions

Our findings indicate that Aβ-associated volume loss occurs in the presence of elevated HFABP irrespective of phospho-tau. This implicates a potentially important role for fatty acid binding proteins in Alzheimer’s disease neurodegeneration.

     

The chemical interactome space between the human host and the genetically defined gut metabotypes

The bacteria that colonize the gastrointestinal tracts of mammals represent a highly selected microbiome that has a profound influence on human physiology by shaping the host''s metabolic and immune system activity. Despite the recent advances on the biological principles that underlie microbial symbiosis in the gut of mammals, mechanistic understanding of the contributions of the gut microbiome and how variations in the metabotypes are linked to the host health are obscure. Here, we mapped the entire metabolic potential of the gut microbiome based solely on metagenomics sequencing data derived from fecal samples of 124 Europeans (healthy, obese and with inflammatory bowel disease). Interestingly, three distinct clusters of individuals with high, medium and low metabolic potential were observed. By illustrating these results in the context of bacterial population, we concluded that the abundance of the Prevotella genera is a key factor indicating a low metabolic potential. These metagenome-based metabolic signatures were used to study the interaction networks between bacteria-specific metabolites and human proteins. We found that thirty-three such metabolites interact with disease-relevant protein complexes several of which are highly expressed in cells and tissues involved in the signaling and shaping of the adaptive immune system and associated with squamous cell carcinoma and bladder cancer. From this set of metabolites, eighteen are present in DrugBank providing evidence that we carry a natural pharmacy in our guts. Furthermore, we established connections between the systemic effects of non-antibiotic drugs and the gut microbiome of relevance to drug side effects and health-care solutions.     

Primary liver cancer incidence and survival in ethnic groups in England, 2001–2007

Background: The patterns of primary liver cancer incidence and survival are not known for detailed ethnic groups within the UK. Methods: Data on patients resident in England diagnosed with primary liver cancer (ICD-10 C22) between 2001 and 2007 were extracted from the National Cancer Data Repository. Age-standardised incidence rate ratios (IRRs) were calculated for different ethnic groups separately for males and females, using the White ethnic groups as baselines. Overall survival was analysed using Cox regression, adjusting sequentially for age, socioeconomic deprivation and co-morbidity. Results: Ethnicity data were available for 75% (13,139/17,458) of primary liver cancer patients. Compared with the White male baseline, Chinese males had the highest IRR. Black African, Bangladeshi, Pakistani and Indian men also had statistically significant high IRRs. Black Caribbean men had a marginally elevated incidence rate compared with White men. In comparison with White women, Pakistani women had the highest IRR. Bangladeshi, Chinese, Black African and Indian women also had high IRRs. As observed in men, Black Caribbean women had an incidence rate closer to that of White women. Pakistani men and women, Black African women and Chinese men had statistically significantly better survival compared with their White counterparts. Conclusion: The variation found in the incidence of primary liver cancer, could be due to established risk factors such as hepatitis B and C infection being more prevalent among certain ethnic groups. Country of birth, age at migration and length of stay in England are likely to be important factors in this disease, and future research should examine these where possible.     

Anti‐hypertensive treatment preserves appetite suppression while preventing cardiovascular adverse effects of tesofensine in rats

Objective:

Tesofensine is a novel triple monoamine reuptake inhibitor which is in development for the treatment of obesity. Preclinical and clinical data suggest that appetite suppression is an important mechanism by which tesofensine exerts its robust weight reducing effect. Notably, the strong hypophagic response to tesofensine treatment is demonstrated to be linked to central stimulation of noradrenergic and dopaminergic neurotransmission. The sympathomimetic mode of action of tesofensine may also associate with the elevated heart rate and blood pressure observed in clinical settings, and we therefore sought experimentally to address this issue.

Design and Methods:

The anorexigenic and cardiovascular effects of tesofensine were studied simultaneously in telemetrized conscious rats in a combined real‐time food intake and cardiovascular telemetry monitoring system.

Results:

Acute administration of tesofensine caused a dose‐dependent hypophagic effect as well as increased heart rate and blood pressure. Interestingly, combined treatment with metoprolol (b₁ adrenoceptor blocker, 10‐20 mg/kg, p.o.) fully prevented the cardiovascular sympathetic effects of tesofensine while leaving the robust inhibitory efficacy on food intake unaffected. Similarly, the angiotensin AT₁ receptor antagonist telmisartan (1.0‐3.0 mg/kg, p.o.) did not interfere with the anti‐obesity effects of tesofensine, however, telmisartan only partially reversed the increase in systolic blood pressure and had no effect on the elevated heart rate induced by tesofensine.

Conclusion:

These data suggests that tesofensine causes elevations in heart rate and blood pressure by increasing sympathetic activity, and that different adrenoceptor subtypes may be responsible for the anti‐obesity and cardiovascular effects of tesofensine.