The difficulty associated with the cultivation of most microorganisms and the complexity of natural microbial assemblages, such as marine plankton or human microbiome, hinder genome reconstruction of representative taxa using cultivation or metagenomic approaches. Here we used an alternative, single cell sequencing approach to obtain high-quality genome assemblies of two uncultured, numerically significant marine microorganisms. We employed fluorescence-activated cell sorting and multiple displacement amplification to obtain hundreds of micrograms of genomic DNA from individual, uncultured cells of two marine flavobacteria from the Gulf of Maine that were phylogenetically distant from existing cultured strains. Shotgun sequencing and genome finishing yielded 1.9 Mbp in 17 contigs and 1.5 Mbp in 21 contigs for the two flavobacteria, with estimated genome recoveries of about 91% and 78%, respectively. Only 0.24% of the assembling sequences were contaminants and were removed from further analysis using rigorous quality control. In contrast to all cultured strains of marine flavobacteria, the two single cell genomes were excellent Global Ocean Sampling (GOS) metagenome fragment recruiters, demonstrating their numerical significance in the ocean. The geographic distribution of GOS recruits along the Northwest Atlantic coast coincided with ocean surface currents. Metabolic reconstruction indicated diverse potential energy sources, including biopolymer degradation, proteorhodopsin photometabolism, and hydrogen oxidation. Compared to cultured relatives, the two uncultured flavobacteria have small genome sizes, few non-coding nucleotides, and few paralogous genes, suggesting adaptations to narrow ecological niches. These features may have contributed to the abundance of the two taxa in specific regions of the ocean, and may have hindered their cultivation. We demonstrate the power of single cell DNA sequencing to generate reference genomes of uncultured taxa from a complex microbial community of marine bacterioplankton. A combination of single cell genomics and metagenomics enabled us to analyze the genome content, metabolic adaptations, and biogeography of these taxa.

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Vaccinia H1-related phosphatase (VHR) is classified as a dual specificity phosphatase. Unlike typical dual specificity phosphatases, VHR lacks the MAPK-binding domain and shows poor activity against MAPKs. We found that EGF receptor (EGFR) was a direct substrate of VHR and that overexpression of VHR down-regulated EGFR phosphorylation, particularly at Tyr-992 residue. Expression of VHR inhibited the activation of phospholipase C␥ and protein kinase C, both downstream effectors of Tyr-992 phosphorylation of EGFR. Decreasing VHR expression by RNA interference caused higher EGFR phosphorylation at Tyr-992. In addition to EGFR, VHR also directly dephosphorylated ErbB2. Consistent with these results, suppression of VHR augmented the foci formation ability of H1299 non-small cell lung cancer (NSCLC) cells, whereas overexpression of VHR suppressed cell growth in both two-and three-dimensional cultures. Expression of VHR also suppressed tumor formation in a mouse xenograft model. Furthermore, VHR expression was significantly lower in NSCLC tissues in comparison to that in normal lung tissues. Collectively, this study shows that down-regulation of VHR expression enhances the signaling of ErbB receptors and may be involved in NSCLC pathogenesis.Among protein modifications, tyrosine phosphorylation is extensively used only in multicellular, eukaryotic organisms. Protein-tyrosine phosphorylation plays an important role in signaling transduction pathways that are involved in embryogenesis, development, and homeostasis. Disorders in proteintyrosine phosphorylation are found in many human diseases from cancer to immune disorders. Although protein phosphorylation is a balanced action of protein kinases and phosphatases, the experimental data of protein phosphatases is proportionally much less than that of protein kinases. Dual specificity phosphatases (DUSPs) 3 are structurally related to protein-tyrosine phosphatases (PTP) and are initially implicated in the down-regulation of MAPKs (1). Distinct from PTPs, which have a deep catalytic cleft; DUSPs have shallow catalytic sites, which permit the less stringent phospho-amino acid specificity of DUSPs (2-4). Several DUSPs including MAPK phosphatases (MKP)-1 to -7, M3/6 (also called VH5), and VHR have been shown to inactivate one or several MAPKs (5-12). The expression of certain DUSPs is increased by mitogenic signaling (5, 13-15). Both ERK and JNK pathways induce the expression of MKPs (15-17). The induction of MKP expression by MAPK signaling may, in turn, lead to the down-regulation of MAPK activities. Recently, many newly identified DUSPs were found to have little or no phosphatase activity against MAPKs, indicating that MAPK inactivation is not the sole function of DUSPs (18 -21). These novel DUSPs are smaller in size compared with MKPs and lack the MAPK-binding domain. These groups of DUSPs have been classified as atypical DUSPs (1). Others' and our recent studies reveal that atypical DUSPs may play a critical role in the regulation of signaling triggered by protein tyrosine...

Early recognition of this critical infection and early initiation of appropriate antibiotic treatment by surgical intervention or drainage is essential.