Post-translational modification of the beta-subunit of the human fibronectin receptor

Monoclonal antibody DH12, directed against the beta-subunit of the fibronectin receptor recognizes a doublet of proteins (100 and 110 kDa) in Western blots of solubilized whole fibroblasts. Pulse-chase experiments with [35S]methionine in human skin fibroblasts suggested that the two proteins might be metabolically related as precursor (100 kDa) and product (110 kDa). Endo H digestion and [3H]fucose labeling suggested that maturation converted the high-mannose oligosaccharides (100 kDa) to the endoglycosidase H resistant complex type (110 kDa). This was supported by N-glycanase digestion and by chemical deglycosylation which showed a single polypeptide. Surface iodination of intact cells labeled only the presumed mature beta-subunit.     

Neutrophil-associated lung injury after the infusion of activated plasma

Previous studies from our laboratory have shown that the infusion of zymosan-activated plasma (ZAP) caused large numbers of neutrophils (PMN) to accumulate in the lung. Although PMN are known to be activated by ZAP, it is unclear whether PMN delayed in the lung by ZAP infusion actually cause lung injury. The present study was designed to examine this question by measuring airway epithelial and endothelial injury. Airway epithelial injury was determined by depositing a known dose of fluorescein isothiocyanate-labeled dextran in the lung and measuring its appearance in the blood, and endothelial injury was measured by injecting colloidal carbon and measuring its accumulation in the microvasculature of the lung. The data show that ZAP infusion caused a mild epithelial and endothelial injury that did not increase either extravascular water or protein. This injury could be prevented either by depleting the animals of PMN or by pretreating them with indomethacin. In addition, the effect of ZAP infusion could be partially restored by transfusing donor PMN into the PMN-depleted animals. We conclude that ZAP infusion produces a mild lung injury that is dependent on PMN and the products of the cyclooxygenase pathway of arachidonic acid metabolism.     

Monocyte kinetics in rabbits

Previous studies of monocytes isolated from peripheral blood have suggested that the lung sequesters these cells and has an important role in monocyte kinetics. However, the lung also provides the first capillary bed encountered by these cells after intravenous injection. A major criticism of the previous reports is that the behavior of monocytes in the lung may be altered as a result of the isolation procedure. The present study addresses this question by comparing the distribution of isolated monocytes (87% pure) in various organs 10 min after they were injected into either the central venous or the arterial circulation. The data show that the extraction of monocytes on the first passage through the lung after intravenous injection was 86.5 +/- 1.5%. After the monocytes had circulated for 10 min, the lungs contained 35.5 +/- 2.5% of the cells after intravenous injection and 29.7 +/- 2.2% after intra-arterial injection (P greater than 0.05). The lung-to-blood recovery ratio after either intravenous or intra-arterial injection showed that the lung contained a marginating pool of monocytes that was five to seven times the size of the circulating pool. The retention of monocytes in a region of the lung was proportional to the regional erythrocyte transit time. The half-life of the radiolabeled monocytes in the circulation was approximately 25 h. We conclude that the lung contains a marginating pool of monocytes and speculate that they concentrate there in preparation for migration into the interstitium and air space of the lung.     

Parental and hybrid Daphnia from the D. longispina complex: long‐term dynamics in genetic structure and significance of overwintering modes

In recent decades, hybridization has become a focus of attention because of its role in evolutionary processes. However, little is known about changes in genetic structure within and between parental species and hybrids over time. Here, we studied processes of genetic change in parental species and hybrids from the Daphnia longispina complex (Crustacea, Cladocera) over a period of six years across ten habitats. These cyclical parthenogens respond to fluctuating environments by switching from asexual to sexual reproduction. Importantly, sexually produced diapausing eggs, which resist extreme conditions such as low temperatures and serve as dispersal stages, are produced to a lower extent by hybrids. Long‐term microsatellite data revealed clear differences between hybrids and parental species. In hybrids, clonal diversity values were lower, whereas heterozygosity and linkage disequilibrium values were higher compared to parental species. Clonal diversity of hybrids responded to the strength of the winter, with cold winters resulting in few genotypes in the following spring. In time windows when only asexual hybrid females survive, priority effects will favour the establishment of the hybrid offspring before hatchlings from parental diapause eggs can enter the community. The constant high levels of heterozygosity maintained by clonal reproduction in hybrids might lead to their successful establishment over time, when they are able to escape competition from both parental species. Although we found evidence that hybrids diversity depends on fluctuating environments, a direct link between hybrid abundance and the strength of winter was missing. Because of reduced adaptability in clonally reproducing hybrids, multiple factors must contribute to promoting their long‐term success in fluctuating environments.     

Sour taste preferences of children relate to preference for novel and intense stimuli

Previous research has suggested that some children have a preference for sour tastes. The origin of this preference remains unclear. We investigated whether preference for sour tastes is related to a difference in rated sour intensity due to physiological properties of saliva, or to an overall preference for intense and new stimuli. Eighty-nine children 7-12 years old carried out a rank-order procedure for preference and category scale for perceived intensity for four gelatins (i.e. 0.0 M, 0.02 M, 0.08 M, 0.25 M added citric acid) and four yellow cards that differed in brightness. In addition, we measured their willingness to try a novel candy and their flow and buffering capacity of their saliva. Fifty-eight percent of the children tested preferred one of the two most sour gelatins. These children had a higher preference for the brightest color (P < 0.05) and were more likely to try the candy with the unknown flavor (P < 0.001) than children who did not prefer the most sour gelatins. Preference for sour taste was not related with differences in rated sour intensity, however those who preferred sour taste had a higher salivary flow (P < 0.05). These findings show that a substantial proportion of young children have a preference for extreme sour taste. This appears to be related to the willingness to try unknown foods and preference for intense visual stimuli. Further research is needed to investigate how these findings can be implemented in the promotion of sour-tasting food such as fruit.     

An EMG-based, muscle driven forward simulation of single support phase of gait

This paper describes the process used to generate lower limb kinematics during single limb stance phase of gait, using musculoskeletal modelling, muscle driven forward simulation and gradient based optimisation techniques (including design of experiment techniques).Initial inputs to the forward simulation process were the normalised quantified muscle activation patterns of 22 muscles, and the initial segmental configuration (both angles and angular velocity) derived from Winter (The biomechanics and motor control of human gait, 1987, University of Waterloo Press, pp. 1-72). Two distinct musculoskeletal models (one including 6 DOF, the other 7 DOF) were defined and a muscle driven forward simulation was implemented.A series of optimisation sequences then were executed to modify the muscle activation patterns and initial segmental configuration, until the system output of the forward simulation approximated the angle data reported by. The accuracy and effectiveness of the analysis sequence proposed and the model response obtained using two distinct musculoskeletal models were verified and analysed with respect to the kinesiology of normal walking.     

Aquarium und Museum für Fischzucht, 1906–1937 in Brüssel,Belgien

In the beginning of last century an aquarium opened in Brussels where besides fishes also a collection of amphibians and reptiles was shown to the public. A small museum was also included. This aquarium was started with the aim just to show freshwater fishes but shortly after the opening also marine species were part of the collection.Curious inhabitants of Brussels who wanted to get acquainted with the unknown animal world and people who were interested in the scientific aspects of fishes, pisciculture, marine life and freshwater world found what they were looking for in the small aquarium and museum. Shortly after the inauguration it was described as ‘…a useful aquarium not only for the scientist who looks for information about all facets of live in water but also for the average visitors who want to get new impressions and enjoys the silence but also want to learn something. Families and schools as well have the possibility to let children and students learn about animals in a total new way’. A few renowned specialists and hydro biologists gave support but the aquarium had to face different problems and the interest of the public dropped off. A short time before World War II the aquarium was closed.     

Genetic Structure of Daphnia galeata Populations in Eastern China

This study presents the first examination of the genetic structure of Daphnia longispina complex populations in Eastern China. Only one species, D. galeata, was present across the eight investigated lakes; as identified by taxon assignment using allelic variation at 15 microsatellite loci. Three genetically differentiated D. galeata subgroups emerged independent of the type of statistical analysis applied. Thus, Bayesian clustering, discriminant analysis based on results from factorial correspondence analysis, and UPGMA clustering consistently showed that populations from two neighbouring lakes were genetically separated from a mixture of genotypes found in other lakes, which formed another two subgroups. Clonal diversity was high in all D. galeata populations, and most samples showed no deviation from Hardy-Weinberg equilibrium, indicating that clonal selection had little effect on the genetic diversity. Overall, populations did not cluster by geographical origin. Further studies will show if the observed pattern can be explained by natural colonization processes or by recent anthropogenic impact on predominantly artificial lakes.     

Immunological roles of Pasteurella multocida toxin (PMT) using a PMT mutant strain

The immunological role of the Pasteurella multocida toxin (PMT) in mice was examined using a PMT mutant strain. After a nasal inoculation, the mutant strain failed to induce interstitial pneumonia. Moreover, PMT had no significant effect on the populations of CD4+, CD8+, CD3+, and CD19+ immunocytes in blood or on the populations of CD4+ and CD8+ splenocytes (P<0.01). However, there was a significant increase in the total number of cells in the BAL samples obtained from the wild-type P. multocida-inoculated mice. On the other hand, the level of IL-1 expression decreased when the macrophages from the bronchio-alveolar lavage were stimulated with PMT. Overall, PMT appears to play some role (stimulating and/or inhibiting) in the immunological responses but further studies will be required to confirm this.     

Plasmid-based genetic modification of human bone marrow-derived stromal cells: analysis of cell survival and transgene expression after transplantation in rat spinal cord

Background

Swine is an important agricultural commodity and biomedical model. Manipulation of the pig genome provides opportunity to improve production efficiency, enhance disease resistance, and add value to swine products. Genetic engineering can also expand the utility of pigs for modeling human disease, developing clinical treatment methodologies, or donating tissues for xenotransplantation. Realizing the full potential of pig genetic engineering requires translation of the complete repertoire of genetic tools currently employed in smaller model organisms to practical use in pigs.

Results

Application of transposon and recombinase technologies for manipulation of the swine genome requires characterization of their activity in pig cells. We tested four transposon systems- Sleeping Beauty, Tol2, piggyBac, and Passport in cultured porcine cells. Transposons increased the efficiency of DNA integration up to 28-fold above background and provided for precise delivery of 1 to 15 transgenes per cell. Both Cre and Flp recombinase were functional in pig cells as measured by their ability to remove a positive-negative selection cassette from 16 independent clones and over 20 independent genomic locations. We also demonstrated a Cre-dependent genetic switch capable of eliminating an intervening positive-negative selection cassette and activating GFP expression from episomal and genome-resident transposons.

Conclusion

We have demonstrated for the first time that transposons and recombinases are capable of mobilizing DNA into and out of the porcine genome in a precise and efficient manner. This study provides the basis for developing transposon and recombinase based tools for genetic engineering of the swine genome.