Transcriptional response to foraging experience in the honey bee mushroom bodies

Enriched environmental conditions induce neuroanatomical plasticity in a variety of vertebrate and invertebrate species. We explored the molecular processes associated with experience-induced plasticity, using naturally occurring foraging behavior in adult worker honey bees (Apis mellifera). In honey bees, the mushroom bodies exhibit neuroanatomical plasticity that is dependent on accumulated foraging experience. To investigate molecular processes associated with foraging experience, we performed a time-course microarray study to examine gene expression changes in the mushroom bodies as a function of days foraged. We found almost 500 genes that were regulated by duration of foraging experience. Bioinformatic analyses of these genes suggest that foraging experience is associated with multiple molecular processes in the mushroom bodies, including some that may contribute directly to neuropil growth, and others that could potentially protect the brain from the effects of aging and physiological stress.     

Matched-Cohort DNA Microarray Diversity Analysis of Methicillin Sensitive and Methicillin Resistant Staphylococcus aureus Isolates from Hospital Admission Patients

As genotyping of S. aureus is important for epidemiologic research and for hygiene management, methods are required for standardized fast and easily applicable evaluation of closely related epidemic strains with high prevalence in hospitals. In this single centre matched control study we compared a new commercially available DNA microarray (IdentiBAC) with standard spa-typing for S. aureus genotyping. Included in the study was a subgroup of 46 MRSA and matched 46 MSSA nasal isolates of the Saarland University Medical Center collected during a state-wide admission prevalence screening. Microarray (MA) and also spa-typing could easily differentiate the genetically diverse MSSA group. However, due to the predominance of CC5/t003 in the MRSA group a sufficient subtyping required analysis of more complex genetic profiles as was shown here by the MA comprising a total number of 334 different hybridization probes. The genetic repertoire of the MRSA group was characterized by more virulence genes as compared to the MSSA group. The standard evaluation of MA results by the original software into CCs, agr-, SCCmec- and capsule-types was substituted in the present study by implementation of multivariate subtyping of closely related CC5 isolates using three different bioinformatic methods (splits graph, cluster dendrogram, and principal component analysis). Each method used was applicable for standardized and highly discriminative subtyping with high concordance. We propose that the identified S. aureus subtypes with characteristic virulence gene profiles are presumably associated also with virulence and pathogenicity in vivo; however, this remains to be analyzed in future studies. MA was superior to spa-typing for epidemiologic and presumably also provide functional respectively virulence associated characterization of S. aureus isolates. This is of specific importance for the hospital setting. In future, MA could become a new standard test for S. aureus typing in combination with multivariate bioinformatic analysis.     

TRPC3 and TRPC6 are essential for normal mechanotransduction in subsets of sensory neurons and cochlear hair cells

Transient receptor potential (TRP) channels TRPC3 and TRPC6 are expressed in both sensory neurons and cochlear hair cells. Deletion of TRPC3 or TRPC6 in mice caused no behavioural phenotype, although loss of TRPC3 caused a shift of rapidly adapting (RA) mechanosensitive currents to intermediate-adapting currents in dorsal root ganglion sensory neurons. Deletion of both TRPC3 and TRPC6 caused deficits in light touch and silenced half of small-diameter sensory neurons expressing mechanically activated RA currents. Double TRPC3/TRPC6 knock-out mice also showed hearing impairment, vestibular deficits and defective auditory brain stem responses to high-frequency sounds. Basal, but not apical, cochlear outer hair cells lost more than 75 per cent of their responses to mechanical stimulation. FM1-43-sensitive mechanically gated currents were induced when TRPC3 and TRPC6 were co-expressed in sensory neuron cell lines. TRPC3 and TRPC6 are thus required for the normal function of cells involved in touch and hearing, and are potential components of mechanotransducing complexes.     

A mate to die for? A model of conditional monogyny in cannibalistic spiders

Monogynous males in various species actively limit themselves to mating with a single female in their lifetime. Whereas previous models have considered monogyny as an obligate mating strategy, here we explore the potential of monogyny to evolve as a context‐specific (conditional) behavior. Using a state‐dependent dynamic game model based on the biology of the cannibalistic spider Argiope bruennichi, we confirm that conditional monogyny can evolve under broad conditions, including an even sex ratio. We predict that males should make a terminal investment when mating with large, virgin females, especially if population density is low and the encounter occurs late in the season. We encourage empirical tests for the existence of conditional monogyny in all species where monogyny occurs in the absence of strict morphological constraints that would make it obligatory.     

Measles IgG antibody index correlates with T2 lesion load on MRI in patients with early multiple sclerosis

Background

B cells and humoral immune responses play an important role in the pathogenesis and diagnosis of multiple sclerosis (MS). A characteristic finding in patients with MS is a polyspecific intrathecal B cell response against neurotropic viruses, specifically against measles virus, rubella virus, and varicella zoster virus, also known as an MRZ reaction (MRZR). Here, we correlated from the routine clinical diagnostics individual IgG antibody indices (AIs) of MRZR with magnetic resonance imaging (MRI) findings in patients with first MS diagnosis.

Methods/Results

MRZR was determined in 68 patients with a clinically isolated syndrome (CIS) or early relapsing-remitting MS (RRMS). Absolute AI values for measles virus, rubella virus, and varicella zoster virus were correlated with T2 lesion load and gadolinium enhancing lesions on cerebral MRI (cMRI) and cMRI combined with spinal MRI (sMRI). Measles virus AI correlated significantly with T2 lesion load on cMRI (p = 0.0312, Mann-Whitney U test) and the sum of lesions on cMRI and sMRI (p = 0.0413). Varicella zoster virus AI also showed a correlation with T2 lesion load on cMRI but did not reach statistical significance (p = 0.2893).

Conclusion

The results confirm MRZR as part of the polyspecific immune reaction in MS with possible prognostic impact on MRI and clinical parameters.Furthermore, the data indicate that intrathecal measles virus IgG production correlates with disease activity on cMRI and sMRI in patients with early MS.     

Open Source Tracking and Analysis of Adult Drosophila Locomotion in Buridan's Paradigm with and without Visual Targets

Background

Insects have been among the most widely used model systems for studying the control of locomotion by nervous systems. In Drosophila, we implemented a simple test for locomotion: in Buridan''s paradigm, flies walk back and forth between two inaccessible visual targets [1]. Until today, the lack of easily accessible tools for tracking the fly position and analyzing its trajectory has probably contributed to the slow acceptance of Buridan''s paradigm.

Methodology/Principal Findings

We present here a package of open source software designed to track a single animal walking in a homogenous environment (Buritrack) and to analyze its trajectory. The Centroid Trajectory Analysis (CeTrAn) software is coded in the open source statistics project R. It extracts eleven metrics and includes correlation analyses and a Principal Components Analysis (PCA). It was designed to be easily customized to personal requirements. In combination with inexpensive hardware, these tools can readily be used for teaching and research purposes. We demonstrate the capabilities of our package by measuring the locomotor behavior of adult Drosophila melanogaster (whose wings were clipped), either in the presence or in the absence of visual targets, and comparing the latter to different computer-generated data. The analysis of the trajectories confirms that flies are centrophobic and shows that inaccessible visual targets can alter the orientation of the flies without changing their overall patterns of activity.

Conclusions/Significance

Using computer generated data, the analysis software was tested, and chance values for some metrics (as well as chance value for their correlation) were set. Our results prompt the hypothesis that fixation behavior is observed only if negative phototaxis can overcome the propensity of the flies to avoid the center of the platform. Together with our companion paper, we provide new tools to promote Open Science as well as the collection and analysis of digital behavioral data.     

Ecological importance of large-diameter trees in a temperate mixed-conifer forest

Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. Although both scaling theory and competition theory make predictions about the relative composition and spatial patterns of large-diameter trees compared to smaller diameter trees, these predictions are rarely tested. We established a 25.6 ha permanent plot within which we tagged and mapped all trees ≥1 cm dbh, all snags ≥10 cm dbh, and all shrub patches ≥2 m(2). We sampled downed woody debris, litter, and duff with line intercept transects. Aboveground live biomass of the 23 woody species was 507.9 Mg/ha, of which 503.8 Mg/ha was trees (SD?=?114.3 Mg/ha) and 4.1 Mg/ha was shrubs. Aboveground live and dead biomass was 652.0 Mg/ha. Large-diameter trees comprised 1.4% of individuals but 49.4% of biomass, with biomass dominated by Abies concolor and Pinus lambertiana (93.0% of tree biomass). The large-diameter component dominated the biomass of snags (59.5%) and contributed significantly to that of woody debris (36.6%). Traditional scaling theory was not a good model for either the relationship between tree radii and tree abundance or tree biomass. Spatial patterning of large-diameter trees of the three most abundant species differed from that of small-diameter conspecifics. For A. concolor and P. lambertiana, as well as all trees pooled, large-diameter and small-diameter trees were spatially segregated through inter-tree distances <10 m. Competition alone was insufficient to explain the spatial patterns of large-diameter trees and spatial relationships between large-diameter and small-diameter trees. Long-term observations may reveal regulation of forest biomass and spatial structure by fire, wind, pathogens, and insects in Sierra Nevada mixed-conifer forests. Sustaining ecosystem functions such as carbon storage or provision of specialist species habitat will likely require different management strategies when the functions are performed primarily by a few large trees as opposed to many smaller trees.     

Biological flora of Central Europe: Ceratocapnos claviculata (L.) Lidén

The eu-oceanic therophytic woodland herb Ceratocapnos claviculata has been expanding north- and eastwards into north temperate and subcontinental regions during the past decades. The rapid range expansion of the species may be an example of a species which is strongly profiting from global change. Against this background, in the present paper we review the taxonomy, morphology, distribution, habitat requirements, life cycle and biology of the species.