Resolving the breakpoints of the 17q21.31 microdeletion syndrome with next-generation sequencing

Recurrent deletions have been associated with numerous diseases and genomic disorders. Few, however, have been resolved at the molecular level because their breakpoints often occur in highly copy-number-polymorphic duplicated sequences. We present an approach that uses a combination of somatic cell hybrids, array comparative genomic hybridization, and the specificity of next-generation sequencing to determine breakpoints that occur within segmental duplications. Applying our technique to the 17q21.31 microdeletion syndrome, we used genome sequencing to determine copy-number-variant breakpoints in three deletion-bearing individuals with molecular resolution. For two cases, we observed breakpoints consistent with nonallelic homologous recombination involving only H2 chromosomal haplotypes, as expected. Molecular resolution revealed that the breakpoints occurred at different locations within a 145 kbp segment of >99% identity and disrupt KANSL1 (previously known as KANSL1). In the remaining case, we found that unequal crossover occurred interchromosomally between the H1 and H2 haplotypes and that this event was mediated by a homologous sequence that was once again missing from the human reference. Interestingly, the breakpoints mapped preferentially to gaps in the current reference genome assembly, which we resolved in this study. Our method provides a strategy for the identification of breakpoints within complex regions of the genome harboring high-identity and copy-number-polymorphic segmental duplication. The approach should become particularly useful as high-quality alternate reference sequences become available and genome sequencing of individuals'' DNA becomes more routine.     

Pseudopod growth and evolution during cell movement is controlled through SCAR/WAVE dephosphorylation

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Highlights? SCAR/WAVE is constitutively phosphorylated at four sites in the acidic domain ? SCAR dephosphorylation is not essential, but greatly stimulates pseudopod growth ? Dephosphorylated SCAR is hyperactive and very unstable ? SCAR is controlled by autoinhibition even when assembled in its regulatory complex     

静磁场对单株人体体表正常菌生长影响的研究

本文通过40mT和120mT两种静磁场作用下表皮葡萄球菌生长过程的研究,发现试验所选强度静磁场加速了表皮葡萄球菌在对数生长期的生长速率,而在进入稳定生长期后其生长速率反而低于对照组,但就整个生长周期而言,静磁场作用下表皮葡萄球菌的总量大于对照组,表明了试验所选静磁场对表皮葡萄球菌生长有一定促进作用.     

Kinetics of anaerobic degradation of glycol-based Type I aircraft deicing fluids

The kinetics of anaerobic degradation of glycol-based Type I aircraft deicing fluids (ADFs) were characterized using suspended-growth fill-and-draw reactors. Both Type I ADFs tested showed near-complete anaerobic degradability. First-order degradation rate constants of 3.5 d^-1 for the propylene glycol-based Type I ADF and 5.2 d^-1 for the ethylene glycol-based Type I ADF were obtained through continuous-culture means under mesophilic conditions (35 °C). Fill-and-draw operation at lower temperatures affected anaerobic degradability only minimally down to 25 °C but substantially below 25 °C. High Type I ADF feed concentrations substantially affected degradability. Batch testing of fill-and-draw reactors resulted in first-order degradation rate constants of 1.9 d^-1 for propylene glycol-based Type I ADF and 3.5 d^-1 for ethylene glycol-based Type I ADF.     

Decreased ascorbic acid levels and brown core development in pears (Pyrus communis L. cv. Conference)

Changes in ascorbic acid content are measured in the cortex tissue of Conference pears stored at various compositions of carbon dioxide and oxygen. Enhanced carbon dioxide levels cause ascorbic acid concentrations to decline. Soon after ascorbic acid has declined below a certain value, browning of the core tissue can be observed. Reducing carbon dioxide levels before this value is reached causes ascorbic acid levels to increase again and prevents browning to a great extent. In preliminary experiments with a photoacoustic laser-based detection system, it was shown that pears that show browning produce ethane, which is most likely a result of membrane peroxidation. Storage conditions, ascorbic acid levels and browning in pears are discussed in relation to diffusion characteristics, energy metabolism and energy maintenance levels of the fruit.