Human 14-3-3 gamma protein results in abnormal cell proliferation in the developing eye of Drosophila melanogaster

During mitosis, correct bipolar chromosome attachment to the mitotic spindle is an essential prerequisite for the equal segregation of chromosomes. The spindle assembly checkpoint can prevent chromosome segregation as long as not all chromosome pairs have obtained bipolar attachment to the spindle. The chromosomal passenger complex plays a crucial role during chromosome alignment by correcting faulty chromosome-spindle interactions (e.g. attachments that do not generate tension). In the process of doing so, the chromosomal passenger complex generates unattached chromosomes, a specific situation that is known to promote checkpoint activity. However, several studies have implicated an additional, more direct role for the chromosomal passenger complex in enforcing the mitotic arrest imposed by the spindle assembly checkpoint. In this review, we discuss the different roles played by the chromosomal passenger complex in ensuring proper mitotic checkpoint function. Additionally, we discuss the possibility that besides monitoring the presence of unattached kinetochores, the spindle assembly checkpoint may also be capable of responding to chromosome-microtubule interactions that do not generate tension and we propose experimental set-ups to study this.     

Role of IgE receptors in IgE antibody-dependent cytotoxicity and phagocytosis of ovarian tumor cells by human monocytic cells

Antibodies directed against tumor-associated antigens are emerging as effective treatments for a number of cancers, although the mechanism(s) of action for some are unclear and still under investigation. We have previously examined a chimeric IgE antibody (MOv18 IgE), against the ovarian tumor-specific antigen, folate binding protein (FBP), and showed that it can direct human PBMC to kill ovarian cancer cells. We have developed a three-color flow cytometric assay to investigate the mechanism by which IgE receptors on U937 monocytes target and kill ovarian tumor cells. U937 monocytes express three IgE receptors, the high-affinity receptor, FcεRI, the low-affinity receptor, CD23, and galectin-3, and mediate tumor cell killing in vitro by two mechanisms, cytotoxicity, and phagocytosis. Our results suggest that CD23 mediates phagocytosis, which is enhanced by upregulation of CD23 on U937 cells with IL-4, whereas FcεRI mediates cytotoxicity. We show that effector : tumor cell bridging is associated with both activities. Galectin-3 does not appear to be involved in tumor cell killing. U937 cells and IgE exerted ovarian tumor cell killing in vivo in our xenograft model in nude mice. Harnessing IgE receptors to target tumor cells suggests the potential of tumor-specific IgE antibodies to activate effector cells in immunotherapy of ovarian cancer. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Can long-distance dispersal shape the local and regional species pool?

Long-distance dispersal events are irregular and their role in shaping plant diversity is often discussed and modeled but rarely studied experimentally. We mimicked long-distance dispersal experimentally by sowing eleven exotic and fourteen native species into a calcareous grassland community in Estonia. Exotic species were randomly chosen from the collection of 500 herbaceous species in the Botanical Garden of the Tartu University. All exotic species were able to complete their life-cycles under the climatic and edaphic conditions in the garden. Native species originated from open dry calcareous habitats in the surroundings of the study site, but did not occur in the experimental grassland. Seven exotic species and seven native species established during the first year. In the third year, there were still three exotic species with five premature individuals, and three sown native species with sixteen individuals in the plots. These results show that long-distance dispersal both within and between regions may have an impact on species composition in target plant communities. If relatively the best established exotic speciesPhyteuma scheuchzeri would be classified as casual, one may conclude that transition among introduction and casual stages corresponds to ten’ rule. The species richness of seedlings, taking both local and sown species into account, was higher in plots with higher native established plant species richness.     

Epidemic Clone I-Specific Genetic Markers in Strains of Listeria monocytogenes Serotype 4b from Foods

Listeria monocytogenes contamination of ready-to-eat foods has been implicated in numerous outbreaks of food-borne listeriosis. However, the health hazards posed by L. monocytogenes detected in foods may vary, and speculations exist that strains actually implicated in illness may constitute only a fraction of those that contaminate foods. In this study, examination of 34 serogroup 4 (putative or confirmed serotype 4b) isolates of L. monocytogenes obtained from various foods and food-processing environments, without known implication in illness, revealed that many of these strains had methylation of cytosines at GATC sites in the genome, rendering their DNA resistant to digestion by the restriction endonuclease Sau3AI. These strains also harbored a gene cassette with putative restriction-modification system genes as well as other, genomically unlinked genetic markers characteristic of the major epidemic-associated lineage of L. monocytogenes (epidemic clone I), implicated in numerous outbreaks in Europe and North America. This may reflect a relatively high fitness of strains with these genetic markers in foods and food-related environments relative to other serotype 4b strains and may partially account for the repeated involvement of such strains in human food-borne listeriosis.     

A maternal influence on the conditioning to plant cues of Aphidius colemani Viereck, parasitizing the aphid Myzus persicae Sulzer

Abstract. The offspring of parasitoids, Aphidius colemani Viereck, reared on Brussels sprouts and emerging from Myzus persicae Sulzer on a fully defined artificial diet, show no preferences in a four-way olfactometer, either for the odour of the diet, the odour of Brussels sprouts, or the odour of two other crucifers (cabbage and Chinese cabbage). A similar lack of odour preferences is shown when the host aphids are exposed for parasitization (for 48 h) on cabbage, Chinese cabbage or wheat. However, if parasitization occurs on Brussels sprouts, a weak but statistically highly significant response to Brussels sprout odour is observed. Although as many as 30–35% of the parasitoids show no response to any odour, another 35% respond positively to the odour of Brussels sprout compared with responses to the odours of cabbage, Chinese cabbage or wheat of only approximately 10%. An analagous result is obtained when the parent parasitoids are reared on cabbage. In this case, significant positive responses of their offspring to cabbage odour occur only if the 48-h parasitization has occurred also on cabbage. However, with parasitoids from Brussels sprouts parasitizing the aphids for 48 h also on Brussels sprouts, the offspring subsequently emerging from pupae excised from the mummies show no preference for Brussels sprout odour. Thus, although the Brussels sprout cue had been experienced early in the development of the parasitoids, they only become conditioned to it when emerging from the mummy. Both male and female parasitoids respond very similarly in all experiments. It is proposed that the chemical cue (probably glucosinolates in these experiments) is most likely in the silk surrounding the parasitoid pupa, and that the mother may leave the chemical in or around the egg at oviposition, inducing chemical defences in her offspring to the secondary plant compounds that the offspring are likely to encounter.     

Are invaders disturbance‐limited? Conservation of mountain grasslands in Central Argentina

Abstract. Extensive areas in the mountain grasslands of central Argentina are heavily invaded by alien species from Europe. A decrease in biodiversity and a loss of palatable species is also observed. The invasibility of the tall‐grass mountain grassland community was investigated in an experiment of factorial design. Six alien species which are widely distributed in the region were sown in plots where soil disturbance, above‐ground biomass removal by cutting and burning were used as treatments. Alien species did not establish in undisturbed plots. All three types of disturbances increased the number and cover of alien species; the effects of soil disturbance and biomass removal was cumulative. Cirsium vulgare and Oenothera erythrosepala were the most efficient alien colonizers. In conditions where disturbances did not continue the cover of aliens started to decrease in the second year, by the end of the third season, only a few adults were established. Consequently, disturbances are needed to maintain alien populations in tall‐grass mountain grasslands. Burning also increased the species richness of native species. We conclude that an efficient way to control the distribution of alien species is to decrease grazing pressure while burning as a traditional management tool may be continued.     

Improving efficiency of breeding for higher crop yield

Summary Exclusive selection for yield raises, the harvest index of self-pollinated crops with little or no gain in total bipmass. In addition to selection for yield, it is suggested that efficient breeding for higher yield requires simultaneous selection for yield's three major, genetically controlled physiological components. The following are needed: (1) a superior rate of biomass accumulation. (2) a superior rate of actual yield accumulation in order to acquire a high harvest index, and (3) a time to harvest maturity that is neither shorter nor longer than the duration of the growing season. That duration is provided by the environment, which is the fourth major determinant of yield. Simultaneous selection is required because genetically established interconnections among the three major physiological components cause: (a) a correlation between the harvest index and days to maturity that is usually negative; (b) a correlation between the harvest index and total biomass that is often negative, and (c) a correlation between biomass and days to maturity that is usually positive. All three physiological components and the correlations among them can be quantified by yield system analysis (YSA) of yield trials. An additive main effects and multiplicative interaction (AMMI) statistical analysis can separate and quantify the genotype × environment interaction (G × E) effect on yield and on each physiological component that is caused by each genotype and by the different environment of each yield trial. The use of yield trials to select parents which have the highest rates of accumulation of both biomass and yield, in addition to selecting for the G × E that is specifically adapted to the site can accelerate advance toward the highest potential yield at each geographical site. Higher yield for many sites will raise average regional yield. Higher yield for multiple regions and continents will raise average yield on a world-wide basis. Genetic and physiological bases for lack of indirect selection for biomass from exclusive selection for yield are explained.     

On the forces that govern clonality versus sexuality in plant communities

Although sexuality is considered evolutionarily progressive, clonality is very common in plants and the prevailing means of reproduction in several community types. I discuss what could be the forces that have influenced the selection among sexual versus non-sexual reproduction at community level. I propose that, among others, the probability of self-competition must have been one of the key factors. The probability of meeting one’s own genes for wasteful competition is higher in communities where clonality prevails (and relatively high mean intra-species relatedness is expected), and higher in communities with low species diversity. On the other hand, lower diversity indicates a higher average fitness of species since the (finite) total pool of resources is distributed among fewer population with high density. I show, using four community types with contrasting diversity and clonality that community fitness (average fitness in the assemblage of species) can be expressed as the product of two variables––anti-diversity and degree of sexuality.     

Development of an Accelerometer-Linked Online Intervention System to Promote Physical Activity in Adolescents

Most adolescents do not achieve the recommended levels of moderate-to-vigorous physical activity (MVPA), placing them at increased risk for a diverse array of chronic diseases in adulthood. There is a great need for scalable and effective interventions that can increase MVPA in adolescents. Here we report the results of a measurement validation study and a preliminary proof-of-concept experiment testing the impact of Zamzee, an accelerometer-linked online intervention system that combines proximal performance feedback and incentive motivation features to promote MVPA. In a calibration study that parametrically varied levels of physical activity in 31 12-14 year-old children, the Zamzee activity meter was shown to provide a valid measure of MVPA (sensitivity in detecting MVPA = 85.9%, specificity = 97.5%, and r = .94 correspondence with the benchmark RT3 accelerometer system; all p < .0001). In a subsequent randomized controlled multi-site experiment involving 182 middle school-aged children assessed for MVPA over 6 wks, intent-to-treat analyses found that those who received access to the Zamzee intervention had average MVPA levels 54% greater than those of a passive control group (p < 0.0001) and 68% greater than those of an active control group that received access to a commercially available active videogame (p < .0001). Zamzee’s effects on MVPA did not diminish significantly over the course of the 6-wk study period, and were statistically significant in both females and males, and in normal- vs. high-BMI subgroups. These results provide promising initial indications that combining the Zamzee activity meter with online proximal performance feedback and incentive motivation features can positively impact MVPA levels in adolescents.