Development of quantitative PCR and metagenomics-based approaches for strain quantification of a defined mixed-strain starter culture

Although the strain composition of mixed cultures may hugely affect production of various fermented foods, such as e.g. cheese, tools for investigating it have so far been limited.     

Sex and Caste-Specific Variation in Compound Eye Morphology of Five Honeybee Species

Ranging from dwarfs to giants, the species of honeybees show remarkable differences in body size that have placed evolutionary constrains on the size of sensory organs and the brain. Colonies comprise three adult phenotypes, drones and two female castes, the reproductive queen and sterile workers. The phenotypes differ with respect to tasks and thus selection pressures which additionally constrain the shape of sensory systems. In a first step to explore the variability and interaction between species size-limitations and sex and caste-specific selection pressures in sensory and neural structures in honeybees, we compared eye size, ommatidia number and distribution of facet lens diameters in drones, queens and workers of five species (Apis andreniformis, A. florea, A. dorsata, A. mellifera, A. cerana). In these species, male and female eyes show a consistent sex-specific organization with respect to eye size and regional specialization of facet diameters. Drones possess distinctly enlarged eyes with large dorsal facets. Aside from these general patterns, we found signs of unique adaptations in eyes of A. florea and A. dorsata drones. In both species, drone eyes are disproportionately enlarged. In A. dorsata the increased eye size results from enlarged facets, a likely adaptation to crepuscular mating flights. In contrast, the relative enlargement of A. florea drone eyes results from an increase in ommatidia number, suggesting strong selection for high spatial resolution. Comparison of eye morphology and published mating flight times indicates a correlation between overall light sensitivity and species-specific mating flight times. The correlation suggests an important role of ambient light intensities in the regulation of species-specific mating flight times and the evolution of the visual system. Our study further deepens insights into visual adaptations within the genus Apis and opens up future perspectives for research to better understand the timing mechanisms and sensory physiology of mating related signals.     

A new single nucleotide polymorphism in the rabbit (Oryctolagus cuniculus) myostatin (MSTN) gene is associated with carcass composition traits

This study aimed at the identification of genetic variations in the myostatin (MSTN) gene and testing their effects on carcass quality traits. We comparatively sequenced Giant Grey (GG) and New Zealand White (NZW) rabbits that were founders of a cross‐bred population. Alignment of our sequence data with the GenBank sequence of the rabbit MSTN gene (Ensembl Gene ID ENSOCUG00000012663) identified three single nucleotide polymorphisms (SNPs). The two novel SNPs (c.?125T>C, c.373+234G>A) and one known SNP (c.747+34C>T) were subsequently analysed for linkage with carcass composition traits in 363 F₂ animals of the cross GG × NZW. Significant linkage was found between c.373+234G>A and nine carcass composition traits (P < 0.05). No significant effects were found for c.?125T>C and c.747+34C>T. Because the linked SNP is located in intron 1 and no genetic variation was found in the coding region, further investigations are necessary to understand the functional effect of the c.373+234G>A variant on the variability of the traits.     

Extracting key information from historical data to quantify the transmission dynamics of smallpox

Background  

Quantification of the transmission dynamics of smallpox is crucial for optimizing intervention strategies in the event of a bioterrorist attack. This article reviews basic methods and findings in mathematical and statistical studies of smallpox which estimate key transmission parameters from historical data.     

Genetic diversity of Syrian Arabian horses

Although Arabian horses have been bred in strains for centuries and pedigrees have been recorded in studbooks, to date, little is known about the genetic diversity within and between these strains. In this study, we tested if the three main strains of Syrian Arabian horses descend from three founders as suggested by the studbook. We examined 48 horses representing Saglawi (n = 18), Kahlawi (n = 16) and Hamdani (n = 14) strains using the Equine SNP70K BeadChip. For comparison, an additional 24 Arabian horses from the USA and three Przewalski's horses as an out group were added. Observed heterozygosis (H_o) ranged between 0.30 and 0.32, expected heterozygosity (H_e) between 0.30 and 0.31 and inbreeding coefficients (F_is) between ?0.02 and ?0.05, indicating high genetic diversity within Syrian strains. Likewise, the genetic differentiation between the three Syrian strains was very low (F_st < 0.05). Hierarchical clustering showed a clear distinction between Arabian and Przewalski's horses. Among Arabian horses, we found three clusters containing either horses from the USA or horses from Syria or horses from Syria and the USA together. Individuals from the same Syrian Arabian horse strain were spread across different sub‐clusters. When analyzing Syrian Arabian horses alone, the best population differentiation was found with three distinct clusters. In contrast to expectations from the studbook, these clusters did not coincide with strain affiliation. Although this finding supports the hypothesis of three founders, the genetic information is not consistent with the currently used strain designation system. The information can be used to reconsider the current breeding practice. Beyond that, Syrian Arabian horses are an important reservoir for genetic diversity.     

Imaging of Orthotopic Glioblastoma Xenografts in Mice Using a Clinical CT Scanner: Comparison with Micro-CT and Histology

PurposeThere is an increasing need for small animal in vivo imaging in murine orthotopic glioma models. Because dedicated small animal scanners are not available ubiquitously, the applicability of a clinical CT scanner for visualization and measurement of intracerebrally growing glioma xenografts in living mice was validated.ResultsTumor volumes (mean±SD mm³) were similar between both CT-modalities (micro-CT: 19.8±19.0, clinical CT: 19.8±18.8; Wilcoxon signed-rank test p = 0.813). Moreover, between reader analyses for each modality showed excellent agreement as demonstrated by correlation analysis (Spearman-Rho >0.9; p<0.01 for all correlations). Histologically measured tumor volumes (11.0±11.2) were significantly smaller due to shrinkage artifacts (p<0.05). CNR and SNR were 2.1±1.0 and 1.1±0.04 for micro-CT and 23.1±24.0 and 1.9±0.7 for the clinical CTscanner, respectively.ConclusionClinical CT scanners may reliably be used for in vivo imaging and volumetric analysis of brain tumor growth in mice.