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Multidrug resistance (MDR) is rapidly increasing in prevalence among isolates of the opportunistic pathogen Pseudomonas aeruginosa, leaving few treatment options. Phage lysins are cell wall hydrolases that have a demonstrated therapeutic potential against Gram-positive pathogens; however, the outer membrane of Gram-negative bacteria prevents most lysins from reaching the peptidoglycan, making them less effective as therapeutics. Nevertheless, a few lysins from Gram-negative bacterial phage can penetrate the bacterial outer membrane with the aid of an amphipathic tail found in the molecule's termini. In this work, we took a phylogenetic approach to systematically identify those lysins from P. aeruginosa phage that would be most effective therapeutically. We isolated and performed preliminary characterization of 16 lysins and chose 2 lysins, PlyPa03 and PlyPa91, which exhibited >5-log killing activity against P. aeruginosa and other Gram-negative pathogens (particularly Klebsiella and Enterobacter). These lysins showed rapid killing kinetics and were active in the presence of high concentrations of salt and urea and under pH conditions ranging from 5.0 to 10.0. Activity was not inhibited in the presence of the pulmonary surfactant beractant (Survanta). While neither enzyme was active in 100% human serum, PlyPa91 retained activity in low serum concentrations. The lysins were effective in the treatment of a P. aeruginosa skin infection in a mouse model, and PlyPa91 protected mice in a lung infection model, making these lysins potential drug candidates for Gram-negative bacterial infections of the skin or respiratory mucosa.

The NuRD complex contains both chromatin remodeling and histone deacetylase activities. Mice lacking the MTA2 subunit of NuRD show developmental defects in pro-B, pre-B, immature B, and marginal zone B cells, and abnormal germinal center B cell differentiation during immune responses. Mta2 inactivation also causes a derepression of Igll1 and VpreB1 genes in pre-B cells. Furthermore, MTA2/NuRD interacts directly with AIOLOS/IKAROS and shows a striking overlap with AIOLOS/IKAROS target genes in human pre-B cells, suggesting a functional interdependence between MTA2/NuRD and AIOLOS. Mechanistically, MTA2 deficiency in mice leads to increased H3K27 acetylation at both Igll1 and VpreB1 promoters. Gene profiling analyses also identify distinct MTA2-dependent transcription programs in pro-B and pre-B cells. In addition, we find a strong synergy between MTA2 and OCA-B in repressing Igll1 and VpreB1 at the pre-B cell stage, and in regulating both the pre-B to immature B transition and splenic B cell development.

The dynamics of ecological change following a major perturbation, known

Background: Peripheral blood skin-homing/cutaneous lymphocyte antigen (CLA)(+) T cells emerge as biomarkers of cutaneous immune activation in patients with inflammatory skin diseases (atopic dermatitis [AD] and alopecia areata [AA]). However, blood phenotyping across these subsets is not yet available in patients with vitiligo. Objective: We sought to measure cytokine production by circulating skin-homing (CLA(+)) versus systemic (CLA(-)) "polar'' CD4(+)/CD8(+) ratio and activated T-cell subsets in patients with vitiligo compared with patients with AA, AD, or psoriasis and control subjects. Methods: Flow cytometry was used to measure levels of the cytokines IFN-gamma, IL-13, IL-9, IL-17, and IL-22 in CD4(+)/CD8(+) T cells in the blood of 19 patients with moderate-to-severe nonsegmental/generalized vitiligo, moderate-to-severe AA (n = 32), psoriasis (n = 24), or AD (n = 43) and control subjects (n = 30). Unsupervised clustering differentiated subjects into groups based on cellular frequencies. Results: Patients with Vitiligo showed the highest CLA(+)/CLA(-) T(H)1/type 1 cytotoxic T-cell polarization, with parallel T(H)2/T(H)9/T(H)17/T(H)22 level increases to levels often greater than those seen in patients with AA, AD, or psoriasis (P < .05). Total regulatory T-cell counts were lower in patients with vitiligo than in control subjects and patients with AD or psoriasis (P < .001). Vitiligo severity correlated with levels of multiple cytokines (P < .1), whereas duration was linked with IFN-gamma and IL-17 levels (P < .04). Patients and control subjects grouped into separate clusters based on blood biomarkers. Conclusions: Vitiligo is characterized by a multicytokine polarization among circulating skin-homing and systemic subsets, which differentiates it from other inflammatory/autoimmune skin diseases. Future targeted therapies should delineate the relative contribution of each cytokine axis to disease perpetuation.

Eukaryotic ribosome biogenesis is initiated with the transcription of pre-ribosomal RNA at the 5' external transcribed spacer, which directs the early association of assembly factors but is absent from the mature ribosome. The subsequent co-transcriptional association of ribosome assembly factors with pre-ribosomal RNA results in the formation of the small subunit processome. Here we show that stable rRNA domains of the small ribosomal subunit can independently recruit their own biogenesis factors in vivo. The final assembly and compaction of the small subunit processome requires the presence of the 5' external transcribed spacer RNA and all ribosomal RNA domains. Additionally, our cryo-electron microscopy structure of the earliest nucleolar preribosomal assembly - the 5' external transcribed spacer ribonucleoprotein - provides a mechanism for how conformational changes in multi-protein complexes can be employed to regulate the accessibility of binding sites and therefore define the chronology of maturation events during early stages of ribosome assembly.

Hydrogen-deuterium exchange mass spectrometry (HDX-MS) is an established, powerful tool for investigating protein-ligand interactions, protein folding, and protein dynamics. However, HDX-MS is still an emergent tool for quality control of biopharmaceuticals and for establishing dynamic similarity between a biosimilar and an innovator therapeutic. Because industry will conduct quality control and similarity measurements over a product lifetime and in multiple locations, an understanding of HDX-MS reproducibility is critical. To determine the reproducibility of continuous-labeling, bottom-up HDX-MS measurements, the present interlaboratory comparison project evaluated deuterium uptake data from the Fab fragment of NISTmAb reference material (PDB: 5K8A) from 15 laboratories. Laboratories reported similar to 89 800 centroid measurements for 430 proteolytic peptide sequences of the Fab fragment (similar to 78 900 centroids), giving similar to 100% coverage, and similar to 10 900 centroid measurements for 77 peptide sequences of the Fc fragment. Nearly half of peptide sequences are unique to the reporting laboratory, and only two sequences are reported by all laboratories. The majority of the laboratories (87%) exhibited centroid mass laboratory repeatability precisions of < s(Lab)> <= (0.15 +/- 0.01) Da (1 sigma((x) over bar)). All laboratories achieved < s(Lab)> <= 0.4 Da. For immersions of protein at T-HDx = (3.6 to 25) degrees C and for D2O exchange times of t(HDX) = (30 s to 4 h) the reproducibility of back-exchange corrected, deuterium uptake measurements for the 15 laboratories is sigma(Laboratories)(reproducibility15) (t(HDX)) = (9.0 +/- 0.9) % (1 sigma). A nine laboratory cohort that immersed samples at T-HDX = 25 degrees C exhibited reproducibility of sigma(25C cohort)(reproducibility) (t(HDX)) = (6.5 +/- 0.6) % for back-exchange corrected, deuterium uptake measurements.

Background: Inflammatory activation of CD8(+) T cells can, when left unchecked, drive severe immunopathology. Hyperstimulation of CD8(+) T cells through a broad set of triggering signals can precipitate hemophagocytic lymphohistiocytosis (HLH), a life-threatening systemic inflammatory disorder. Objective: The mechanism linking CD8(+) T-cell hyperactivation to pathology is controversial, with excessive production of IFN-gamma and, more recently, excessive consumption of IL-2, which are proposed as competing hypotheses. We formally tested the proximal mechanistic events of each pathway in a mouse model of HLH. Methods: In addition to reporting a complete autosomal recessive IFN-gamma receptor 1-deficient patient with multiple aspects of HLH pathology, we used the mouse model of perforin (Prf1)(KO) mice infected with lymphocytic choriomeningitis virus to genetically eliminate either IFN-gamma production or CD25 expression and assess the immunologic, hematologic, and physiologic disease measurement. Results: We found a striking dichotomy between the mechanistic basis of the hematologic and inflammatory components of CD8(+) T cell-mediated pathology. The hematologic features of HLH were completely dependent on IFN-gamma production, with complete correction after loss of IFN-gamma production without any role for CD8(+) T cell-mediated IL-2 consumption. By contrast, the mechanistic contribution of the immunologic features was reversed, with no role for IFN-gamma production but substantial correction after reduction of IL-2 consumption by hyperactivated CD8(+) T cells. These results were complemented by the characterization of an IFN-gamma receptor 1-deficient patients with HLH-like disease, in whom multiple aspects of HLH pathology were observed in the absence of IFN-gamma signaling. Conclusion: These results synthesize the competing mechanistic models of HLH pathology into a dichotomous pathogenesis driven through discrete pathways. A holistic model provides a new paradigm for understanding HLH and, more broadly, the consequences of CD8(+) T-cell hyperactivation, thereby paving the way for clinical intervention based on the features of HLH in individual patients.

Data on stocks and flows of international migration are necessary to understand migrant patterns and trends and to monitor and evaluate migration-relevant international development agendas. Many countries do not publish data on bilateral migration flows. At least six methods have been proposed recently to estimate bilateral migration flows between all origin-destination country pairs based on migrant stock data published by the World Bank and United Nations. We apply each of these methods to the latest available stock data to provide six estimates of five-year bilateral migration flows between 1990 and 2015. To assess the resulting estimates, we correlate estimates of six migration measures from each method with equivalent reported data where possible. Such systematic efforts at validation have largely been neglected thus far. We show that the correlation between the reported data and the estimates varies widely among different migration measures, over space, and over time. We find that the two methods using a closed demographic accounting approach perform consistently better than the four other estimation approaches.

The AAA proteins are a family of enzymes that play key roles in diverse dynamic cellular processes, ranging from proteostasis to directional intracellular transport. Dysregulation of AAA proteins has been linked to several diseases, including cancer, suggesting a possible therapeutic role for inhibitors of these enzymes. In the past decade, new chemical probes have been developed for AAA proteins including p97, dynein, midasin, and ClpC1. In this review, we discuss how these compounds have been used to study the cellular functions and conformational dynamics of AAA proteins. We discuss future directions for inhibitor development and early efforts to utilize AAA protein inhibitors in the clinical setting.