Plantar hypoesthesia alters time-to-boundary measures of postural control

Our purpose was to identify the effect of diminished plantar cutaneous sensation on time-to-boundary (TTB) measures of postural control during double and single limb quiet standing. Thirty-two healthy young adults underwent 10 min of ice immersion of the plantar aspect of the feet prior to balance testing. On a different day, the subjects did not receive this intervention prior to testing. A 2 × 2 vision (eyes open, eyes closed) by sensation (control, hypoesthesia) repeated measures design was used to analyze the TTB measures. In double limb stance, there were significant interactions between sensation and vision for the absolute TTB minimum and the mean of TTB minima in the anteroposterior (AP) direction. There was a significant increase in both measures after sensation was diminished with eyes closed compared to the control, but not with eyes open. In single limb stance, the TTB absolute minimum, the mean of TTB minima in the AP direction, and the standard deviation of TTB minima significantly increased with hypoesthesia regardless of vision. No significant differences were found in the medial–lateral (ML) direction for any of the TTB measures in double or single limb stance. Sensory information from the plantar cutaneous receptors appears to be most important in the maintenance of AP postural control.     

Strain-specific Influence of Microcystis Aeruginosa on Food Ingestion and Assimilation of some Cladocerans and Copepods

Ingestion rates where estimated for daphnids, Cyclops spp. and Bosmina (Eubosmina) coregoni thersites fed hepatotoxic and non-toxic M. aeruginosa either separate or mixed with the readily available food alga Ankistrodesmus falcatus. The ingestion rates of hepatotoxic strains of M. aeruginosa are very low compared with those of A. falcatus or non-toxic M. aeruginosa HUB 5-3 fed to Daphnia magna or D. longispina. However, a close relationship between ingestion rate of different M. aeruginosa strains and their toxicity could not be observed. Addition of the toxic strain M. aeruginosa HUB 5-2-4 reduces the ingestion rates of A. falcatus progressively due to increased food rejection by D. magna. Additionally, the assimilation efficiency of M. aeruginosa HUB 5-2-4 is two times lower compared with A. falcatus and M. aeruginosa HUB 5-3 leading to strong starvation.     

Detection of bird schistosomes in lakes by PCR and filter-hybridization

Many lakes around the world are contaminated with bird schistosome cercariae, which penetrate into human skin, causing an itching dermatitis called "swimmers' itch." Bathers could be forewarned from exposure to the larvae and ecological examinations could be performed, when a sensitive method to detect the parasites in aquatic systems, where lots of organisms hinder microscopic examinations, would be available. For this purpose we cloned, sequenced, and analyzed a 396 bp tandem repeated DNA sequence from Trichobilharzia ocellata (ToSau3A), and employed it for developing molecular detection assays. It hybridized with less than 100 pg DNA from different Trichobilharzia species (T. ocellata, Trichobilharzia franki, and Trichobilharzia regenti), but not with 10 ng DNA from other related or sympatric trematodes. A PCR assay, amplifying this sequence with the same specificity, detected 100 fg T. ocellata DNA, 1 cercaria in 0.5 g plankton, and 2 cercariae in 0.5 g host snail tissues.     

Rapid identification of Arabidopsis insertion mutants by non-radioactive detection of T-DNA tagged genes

To assist in the analysis of plant gene functions we have generated a new Arabidopsis insertion mutant collection of 90 000 lines that carry the T-DNA of Agrobacterium gene fusion vector pPCV6NFHyg. Segregation analysis indicates that the average frequency of insertion sites is 1.29 per line, predicting about 116 100 independent tagged loci in the collection. The average T-DNA copy number estimated by Southern DNA hybridization is 2.4, as over 50% of the insertion loci contain tandem T-DNA copies. The collection is pooled in two arrays providing 40 PCR templates, each containing DNA from either 4000 or 5000 individual plants. A rapid and sensitive PCR technique using high-quality template DNA accelerates the identification of T-DNA tagged genes without DNA hybridization. The PCR screening is performed by agarose gel electrophoresis followed by isolation and direct sequencing of DNA fragments of amplified T-DNA insert junctions. To estimate the mutation recovery rate, 39 700 lines have been screened for T-DNA tags in 154 genes yielding 87 confirmed mutations in 73 target genes. Screening the whole collection with both T-DNA border primers requires 170 PCR reactions that are expected to detect a mutation in a gene with at least twofold redundancy and an estimated probability of 77%. Using this technique, an M2 family segregating a characterized gene mutation can be identified within 4 weeks.     

Marker rescue studies of the transfer of recombinant DNA to Streptococcus gordonii in vitro, in foods and gnotobiotic rats

A plasmid marker rescue system based on restoration of the nptII gene was established in Streptococcus gordonii to study the transfer of bacterial and transgenic plant DNA by transformation. In vitro studies revealed that the marker rescue efficiency depends on the type of donor DNA. Plasmid and chromosomal DNA of bacteria as well as DNA of transgenic potatoes were transferred with efficiencies ranging from 8.1 x 10(-6) to 5.8 x 10(-7) transformants per nptII gene. Using a 792-bp amplification product of nptII the efficiency was strongly decreased (9.8 x 10(-9)). In blood sausage, marker rescue using plasmid DNA was detectable (7.9 x 10(-10)), whereas in milk heat-inactivated horse serum (HHS) had to be added to obtain an efficiency of 2.7 x 10(-11). No marker rescue was detected in extracts of transgenic potatoes despite addition of HHS. In vivo transformation of S. gordonii LTH 5597 was studied in monoassociated rats by using plasmid DNA. No marker rescue could be detected in vivo, although transformation was detected in the presence of saliva and fecal samples supplemented with HHS. It was also shown that plasmid DNA persists in rat saliva permitting transformation for up to 6 h of incubation. It is suggested that the lack of marker rescue is due to the absence of competence-stimulating factors such as serum proteins in rat saliva.     

Genome-Based Identification of Active Prophage Regions by Next Generation Sequencing in Bacillus licheniformis DSM13

Prophages are viruses, which have integrated their genomes into the genome of a bacterial host. The status of the prophage genome can vary from fully intact with the potential to form infective particles to a remnant state where only a few phage genes persist. Prophages have impact on the properties of their host and are therefore of great interest for genomic research and strain design. Here we present a genome- and next generation sequencing (NGS)-based approach for identification and activity evaluation of prophage regions. Seven prophage or prophage-like regions were identified in the genome of Bacillus licheniformis DSM13. Six of these regions show similarity to members of the Siphoviridae phage family. The remaining region encodes the B. licheniformis orthologue of the PBSX prophage from Bacillus subtilis. Analysis of isolated phage particles (induced by mitomycin C) from the wild-type strain and prophage deletion mutant strains revealed activity of the prophage regions BLi_Pp2 (PBSX-like), BLi_Pp3 and BLi_Pp6. In contrast to BLi_Pp2 and BLi_Pp3, neither phage DNA nor phage particles of BLi_Pp6 could be visualized. However, the ability of prophage BLi_Pp6 to generate particles could be confirmed by sequencing of particle-protected DNA mapping to prophage locus BLi_Pp6. The introduced NGS-based approach allows the investigation of prophage regions and their ability to form particles. Our results show that this approach increases the sensitivity of prophage activity analysis and can complement more conventional approaches such as transmission electron microscopy (TEM).     

Do urban canyons influence street level grass pollen concentrations?

In epidemiological studies, outdoor exposure to pollen is typically estimated using rooftop monitoring station data, whilst exposure overwhelmingly occurs at street level. In this study the relationship between street level and roof level grass pollen concentrations was investigated for city centre street canyon environments in Aarhus, Denmark, and London, UK, during the grass pollen seasons of 2010 and 2011 respectively. For the period mid-day to late evening, street level concentrations in both cities tended to be lower than roof-level concentrations, though this difference was found to be statistically significant only in London. The ratio of street/roof level concentrations was compared with temperature, relative humidity, wind speed and direction, and solar radiation. Results indicated that the concentration ratio responds to wind direction with respect to relative canyon orientation and local source distribution. In the London study, an increase in relative humidity was linked to a significant decrease in street/roof level concentration ratio, and a possible causative mechanism involving moisture mediated pollen grain buoyancy is proposed. Relationships with the other weather variables were not found to be significant in either location. These results suggest a tendency for monitoring station data to overestimate exposure in the canyon environment.