Social organization of a solitary carnivore: spatial behaviour, interactions and relatedness in the slender mongoose

The majority of carnivore species are described as solitary, but little is known about their social organization and interactions with conspecifics. We investigated the spatial organization and social interactions as well as relatedness of slender mongooses (Galerella sanguinea) living in the southern Kalahari. This is a little studied small carnivore previously described as solitary with anecdotal evidence for male associations. In our study population, mongooses arranged in spatial groups consisting of one to three males and up to four females. Male ranges, based on sleeping sites, were large and overlapping, encompassing the smaller and more exclusive female ranges. Spatial groups could be distinguished by their behaviour, communal denning and home range. Within spatial groups animals communally denned in up to 33% of nights, mainly during winter months, presumably to gain thermoregulatory benefits. Associations of related males gained reproductive benefits likely through increased territorial and female defence. Our study supports slender mongooses to be better described as solitary foragers living in a complex system of spatial groups with amicable social interactions between specific individuals. We suggest that the recognition of underlying ‘hidden' complexities in these apparently ‘solitary' organizations needs to be accounted for when investigating group living and social behaviour

Female-biased dispersal in the solitarily foraging slender mongoose, Galerella sanguinea, in the Kalahari

Sex-biased dispersal is common in most mammals, but a female bias is less so and exceptionally rare in solitary mammals. Here we present genetic and observational evidence for strong female-biased dispersal in a solitary foraging small carnivore, the slender mongoose. We suggest that females benefit from dispersal by avoiding kin competition over local resources and inbreeding, while males can benefit from philopatry through kin cooperation leading to an increased success in female defence. The comparison between our observations and those of a previous study in Tanzania suggest that there is ecologically influenced flexibility in dispersal patterns within this species, influencing sex-specific benefits of dispersal and philopatry. Comparing our results with those on the closely related, more social mongoose species in which both sexes commonly disperse suggests that dispersal patterns are linked to a species' social system by the opportunity, or lack of it, in philopatry to obtain unrelated mating partners and gain indirect fitness benefits

Experimental and computational analyses reveal that environmental restrictions shape HIV-1 spread in 3D cultures

Here, using an integrative experimental and computational approach, Imle et al. show how cell motility and density affect HIV cell-associated transmission in a three-dimensional tissue-like culture system of CD4+ T cells and collagen, and how different collagen matrices restrict infection by cell-free virions

Age and gender as determinants of the bone quality of the greater tuberosity: A HR-pQCT cadaver study

Background: Age-dependent trabecular changes of the humeral head might weaken the fixation of suture anchors used for rotator cuff (RC) repair. This might lead to suture anchor loosening and thus compromise the integrity of the repair. The aim of this study was to analyze whether the trabecular microstructure within the RC footprint is influenced by age, gender or handedness. Methods: Axial HR-pQCT scans (Scanco Medical) of 64 freshly frozen cadaveric human humeral head specimens (age 72.3 +/- 17.4 years) were analyzed to determine the bone volume-to-total volume ratio (BV/TV), trabecular thickness (Trab Th), trabecular number (Trab N) and connectivity density (Conn Dens). Within the RC footprint, 2 volumes of interest (VOI), posteromedial (PM) and anterolateral (AL) and one control VOI in the subarticular bone (SC) were set. Results: The highest BV/TV was found in SC: 0.22 +/- 0.06% vs. PM: 0.04 +/- 0.05% vs. AL: 0.02 +/- 0.04%; p < 0.05. Trab Th accounted for 0.26 +/- 0.05 mu m in SC, 0.23 +/- 0.09 mu m in AL and 0.21 +/- 0.05 mu m in PM. In parallel, Trab N and Conn Dens were found to be the highest in SC. Gender analysis yielded higher values for BV/TV, Trab Th, Trab N and Conn Dens for PM in males compared to females (p < 0.05). There were no significant findings when comparing both sides. We furthermore found a strong inverse correlation between age and BV/TV, which was more pronounced in the female specimens (r = -0.72, p < 0.00001). Conclusions: The presented microarchitectural data allow for future subtle biomechanical testing comprising knowledge on age-and sex-related changes of the tuberosities of the humeral head. Furthermore, the insights on the trabecular structure of the humeral head of the elderly may lead to the development of new fixation materials in bone with inferior bone quality

Micro-endoscopy of the human vas deferens: a feasibility study of a novel device in several ex vivo models

The aim of this study was to show limitation as well as potential of micro-endoscopy techniques as an innovative diagnostic and therapeutic approach in andrology. Two kinds of custom-made micro-endoscopes (ME) were tested in ex vivo vas deferens specimen and in post-mortem whole body. The semi-rigid ME included a micro-optic (0.9mm outer diameter [OD], 10.000 pixels, 120 degrees vision angle [VE], 3-20mm field depth [FD]) and an integrated fibre-optic light source. The flexible ME was composed of a micro-optic (OD=0.6mm, 6.000 pixels, 120 degrees VE, 3-20mm FD). The ex vivo study included retrograde investigation of the vas deferens (surgical specimen n=9, radical prostatectomy n=3). The post-mortem investigation (n=4) included the inspection of the vas deferens via both approaches. The results showed that antegrade and retrograde rigid endoscopy of the vas deferens were achieved as a diagnostic tool. The working channel enabled therapeutic use including biopsies or baskets. Using the flexible ME, the orifices of the ejaculatory ducts were identified. In vivo cadaveric retrograde cannulation of the orifices was successful. Post-mortem changes of verumontanum hindered the examinations beyond. Orifices were identified shaded behind a thin transparent membrane. Antegrade vasoscopy using flexible ME was possible up to the internal inguinal ring. Further advancement was impossible because of anatomical angle and lack adequate vision guidance. The vas deferens interior was clearly visible and was documented by pictures and movies. Altogether, the described ME techniques were feasible and effective, offering the potential of innovative diagnostic and therapeutic approaches for use in the genital tract. Several innovative indications could be expected

Spatial heterogeneity and peptide availability determine CTL killing efficiency in vivo

The rate at which a cytotoxic T lymphocyte (CTL) can survey for infected cells is a key ingredient of models of vertebrate immune responses to intracellular pathogens. Estimates have been obtained using in vivo cytotoxicity assays in which peptide-pulsed splenocytes are killed by CTL in the spleens of immunised mice. However the spleen is a heterogeneous environment and splenocytes comprise multiple cell types. Are some cell types intrinsically more susceptible to lysis than others? Quantitatively, what impacts are made by the spatial distribution of targets and effectors, and the level of peptide-MHC on the target cell surface? To address these questions we revisited the splenocyte killing assay, using CTL specific for an epitope of influenza virus. We found that at the cell population level T cell targets were killed more rapidly than B cells. Using modeling, quantitative imaging and in vitro killing assays we conclude that this difference in vivo likely reflects different migratory patterns of targets within the spleen and a heterogeneous distribution of CTL, with no detectable difference in the intrinsic susceptibilities of the two populations to lysis. Modeling of the stages involved in the detection and killing of peptide-pulsed targets in vitro revealed that peptide dose influenced the ability of CTL to form conjugates with targets but had no detectable effect on the probability that conjugation resulted in lysis, and that T cell targets took longer to lyse than B cells. We also infer that incomplete killing in vivo of cells pulsed with low doses of peptide may be due to a combination of heterogeneity in peptide uptake and the dissociation, but not internalisation, of peptide-MHC complexes. Our analyses demonstrate how population-averaged parameters in models of immune responses can be dissected to account for both spatial and cellular heterogeneity

Comparative studies on the structure of an upland African stream ecosystem

Upland stream systems have been extensively investigated in Europe, North America and Australasia and many of the central ideas concerning their function are based on these systems. One central paradigm, the river continuum concept is ultimately derived from those North American streams whose catchments remain forested with native vegetation. Streams of the tropics may or may not fit the model. They have been little studied. The Amani Nature Reserve in the East Usambara Mountains of north-eastern Tanzania offers an opportunity to bring these naturally forested systems to the attention of the ecological community. This article describes a comparison made between two lengths of the River Dodwe in this area. The work was carried out by a group of postgraduate students from eighteen European and African countries with advice from five staff members, as part of a course organised by the Tropical Biology Association. Rigorous efforts were made to standardise techniques, in a situation where equipment and laboratory facilities were very basic, through a management structure and deliberate allocation of work to specialists in each area.The article offers a summary of invertebrate communities found in the stream and its biomass. Crabs seem to be the key organism in both sections of the streams

Decreased levels of BAG3 in a family with a rare variant and in idiopathic dilated cardiomyopathy.

The most common cause of dilated cardiomyopathy and heart failure (HF) is ischemic heart disease; however, in a third of all patients the cause remains undefined and patients are diagnosed as having idiopathic dilated cardiomyopathy (IDC). Recent studies suggest that many patients with IDC have a family history of HF and rare genetic variants in over 35 genes have been shown to be causative of disease. We employed whole-exome sequencing to identify the causative variant in a large family with autosomal dominant transmission of dilated cardiomyopathy. Sequencing and subsequent informatics revealed a novel 10-nucleotide deletion in the BCL2-associated athanogene 3 (BAG3) gene (Ch10:del 121436332_12143641: del. 1266_1275 [NM 004281]) that segregated with all affected individuals. The deletion predicted a shift in the reading frame with the resultant deletion of 135 amino acids from the C-terminal end of the protein. Consistent with genetic variants in genes encoding other sarcomeric proteins there was a considerable amount of genetic heterogeneity in the affected family members. Interestingly, we also found that the levels of BAG3 protein were significantly reduced in the hearts from unrelated patients with end-stage HF undergoing cardiac transplantation when compared with non-failing controls. Diminished levels of BAG3 protein may be associated with both familial and non-familial forms of dilated cardiomyopathy

FLNC Gene Splice Mutations Cause Dilated\ua0Cardiomyopathy

OBJECTIVE: To identify novel dilated cardiomyopathy (DCM) causing genes, and to elucidate the pathological mechanism leading to DCM by utilizing zebrafish as a model organism. BACKGROUND: DCM, a major cause of heart failure, is frequently familial and caused by a genetic defect. However, only 50% of DCM cases can be attributed to a known DCM gene variant, motivating the ongoing search for novel disease genes. METHODS: We performed whole exome sequencing (WES) in two multigenerational Italian families and one US family with arrhythmogenic DCM without skeletal muscle defects, in whom prior genetic testing had been unrevealing. Pathogenic variants were sought by a combination of bioinformatic filtering and cosegregation testing among affected individuals within the families. We performed function assays and generated a zebrafish morpholino knockdown model. RESULTS: A novel filamin C gene splicing variant (FLNC c.7251+1 G>A) was identified by WES in all affected family members in the two Italian families. A separate novel splicing mutation (FLNC c.5669-1delG) was identified in the US family. Western blot analysis of cardiac heart tissue from an affected individual showed decreased FLNC protein, supporting a haploinsufficiency model of pathogenesis. To further analyze this model, a morpholino knockdown of the ortholog filamin Cb in zebrafish was created which resulted in abnormal cardiac function and ultrastructure. CONCLUSIONS: Using WES, we identified two novel FLNC splicing variants as the likely cause of DCM in three families. We provided protein expression and in vivo zebrafish data supporting haploinsufficiency as the pathogenic mechanism leading to DCM