Phylogenetics and evolution of the eastern Asian-eastern North American disjunct aphid tribe,Hormaphidini (Hemiptera: Aphididae)

A conspicuous biogeographic pattern of the Northern Hemisphere is the disjunct occurrence of related taxa on different continents. Perhaps best studied in plants, this pattern includes disjunct distributions of genera in eastern Asia and eastern North America. Such continental disjunctions are thought to be the remnants of a mostly continuously distributed, mixed mesophytic forest dating to the Miocene, which subsequently became fragmented by geological and climatic changes. Some highly host-specific insects, namely aphids, live on descendants of the mixed mesophytic forest taxa and exhibit the same disjunct distributions as that of their host plants. We estimated the phylogeny of Hormaphidini aphids, which host-alternate between witch-hazel (Hamamelis; an eastern Asian-eastern North American disjunct genus) and birch (Betula). Based on partial nuclear elongation factor 1alpha and mitochondrial tRNA leucine/cytochrome oxidase II sequences, trees inferred from maximum-parsimony and maximum-likelihood showed strong support for two monophyletic genera (Hamamelistes and Hormaphis), each containing a clade of Japanese and a clade of North American species. The estimated divergence dates of Asian and North American clades in both genera was 20-30 million years ago, consistent with the idea that aphids may have experienced the same vicariance events as those of their host plants.     

The gene for juvenile hyaline fibromatosis maps to chromosome 4q21

Juvenile hyaline fibromatosis (JHF) is an autosomal recessive condition characterized by multiple subcutaneous nodular tumors, gingival fibromatosis, flexion contractures of the joints, and an accumulation of hyaline in the dermis. We performed a genomewide linkage search in two families with JHF from the same region of the Indian state of Gujarat and identified a region of homozygosity on chromosome 4q21. Dense microsatellite analyses within this interval in five families with JHF who were from diverse origins demonstrate that all are compatible with linkage to chromosome 4q21 (multipoint LOD score 5.5). Meiotic recombinants place the gene for JHF within a 7-cM interval bounded by D4S2393 and D4S395.     

CD4+CD25+ regulatory T cells suppress differentiation and functions of Th1 and Th2 cells,Leishmania major infection,and colitis in mice

Regulatory T cells play a major role in modulating the immune response. However, most information on these cells centers on autoimmunity, and there is also considerable controversy on the functional characteristics of these cells. Here we provide direct in vitro and in vivo evidence that CD4+CD25+ regulatory T cells inhibit the differentiation and functions of both Th1 and Th2 cells. Importantly, CD4+CD25+ T cells suppressed the disease development of Leishmania major infection in SCID mice reconstituted with naive CD4+CD25- T cells. Furthermore, CD4+CD25+ T cells inhibited the development of colitis induced by both Th1 and Th2 cells in SCID mice. Our results therefore document that CD4+CD25+ regulatory T cells suppress both Th1 and Th2 cells and that these regulatory T cells have a profound therapeutic potential against diseases induced by both Th1 and Th2 cells in vivo.     

Quality Control Methods in Accelerometer Data Processing: Defining Minimum Wear Time

Background

When using accelerometers to measure physical activity, researchers need to determine whether subjects have worn their device for a sufficient period to be included in analyses. We propose a minimum wear criterion using population-based accelerometer data, and explore the influence of gender and the purposeful inclusion of children with weekend data on reliability.

Methods

Accelerometer data obtained during the age seven sweep of the UK Millennium Cohort Study were analysed. Children were asked to wear an ActiGraph GT1M accelerometer for seven days. Reliability coefficients(r) of mean daily counts/minute were calculated using the Spearman-Brown formula based on the intraclass correlation coefficient. An r of 1.0 indicates that all the variation is between- rather than within-children and that measurement is 100% reliable. An r of 0.8 is often regarded as acceptable reliability. Analyses were repeated on data from children who met different minimum daily wear times (one to 10 hours) and wear days (one to seven days). Analyses were conducted for all children, separately for boys and girls, and separately for children with and without weekend data.

Results

At least one hour of wear time data was obtained from 7,704 singletons. Reliability increased as the minimum number of days and the daily wear time increased. A high reliability (r = 0.86) and sample size (n = 6,528) was achieved when children with ≥ two days lasting ≥10 hours/day were included in analyses. Reliability coefficients were similar for both genders. Purposeful sampling of children with weekend data resulted in comparable reliabilities to those calculated independent of weekend wear.

Conclusion

Quality control procedures should be undertaken before analysing accelerometer data in large-scale studies. Using data from children with ≥ two days lasting ≥10 hours/day should provide reliable estimates of physical activity. It’s unnecessary to include only children with accelerometer data collected during weekends in analyses.     

Patterns of [13N]ammonium uptake and assimilation by Frankia HFPArl3

Nitrogen-starved cells of Frankia strain HFPArl3 incorporated [¹³N]-labeled ammonium into glutamine serine (glutamate, alanine, aspartate), after five-minute radioisotope exposures. High initial endogenous pools of glutamate were reduced, while total glutamine increased, during short term NH _inf4 ^sup+ incubation. Preincubation of cells in methionine sulfoximine (MSX) resulted in [¹³N]glutamine reduced by more than 80%, while [¹³N]glutamate and [¹³N]alanine levels increased. The results suggest that glutamine synthetase is the primary enzyme of ammonium assimilation, and that glutamate dehydrogenase and alanine dehydrogenase may also function in ammonium assimilation at low levels. Efflux of [¹³N]serine and lesser amounts of [¹³N]glutamine was detected from the Frankia cells. The identity of both Ser and Gln in the extracellular compartment was confirmed with gas chromatography/mass spectrometry. Serine efflux may be of significance in nitrogen transfer in Frankia.Abbreviations Pthr phosphothreonine - Aad -amino-adipate - MSX methionine sulfoximine     

Caffeine inhibition of cytokinesis: Ultrastructure of cell plate formation/degradation

Summary Caffeine is a potent inhibitor of cell plate formation in dividing plant cells. Previous studies living cells reveal that the drug always permits the cell plate to arise and grow normally until about 80% complete, but then causes it to break down. In the present investigation we examine this formation/degradation cycle at the ultrastructure level. Our results show that during the formation phase the caffeine treated plate is indistinguishable from untreated controls. Phragmoplast microtubules arise and align in the interzone, Golgi vesicles are produced and aggregate in a line that defines the young cell plate, and considerable fusion of these vesicles occurs to form islands of plate material. However, under the influence of caffeine these islands do not fuse to form the enlarged lamellar expanses characteristic of maturing cell plates. Instead, the partially fused material reverts to small vesicles which appear to become resorbed by the cellular membrane systems. The resorption process continues leaving no evidence of the previously developing plate, although occasionally we observe a stub of fused vesicles attached to the parent wall. Following cell plate disintegration the reformed nuclei move close together and occupy the central region of the cell. These observations focus attention on the consolidation phase of cell plate formation as the one being maximally affected by caffeine.Dedicated to the memory of Professor Oswald Kiermayer