Publications search

Background: Centromeres are essential for accurate chromosome segregation, yet sequence conservation is low even among closely related species. Centromere drive predicts rapid turnover because some centromeric sequences may compete better than others during female meiosis. In addition to sequence composition, longer centromeres may have a transmission advantage. Results: We report the first observations of extremely long centromeres, covering on average 34 % of the chromosomes, in the red imported fire ant Solenopsis invicta. By comparison, cytological examination of Solenopsis geminata revealed typical small centromeric constrictions. Bioinformatics and molecular analyses identified CenSol, the major centromeric satellite DNA repeat. We found that CenSol sequences are very similar between the two species but the CenSol copy number in S. invicta is much greater than that in S. geminata. In addition, centromere expansion in S. invicta is not correlated with the duplication of CenH3. Comparative analyses revealed that several closely related fire ant species also possess long centromeres. Conclusions: Our results are consistent with a model of simple runaway centromere expansion due to centromere drive. We suggest expanded centromeres may be more prevalent in hymenopteran insects, which use haplodiploid sex determination, than previously considered.

The 2016 Lasker-DeBakey Clinical Medical Research Award has been presented to Ralf F. W. Bartenschlager, Charles M. Rice, and Michael J. Sofia for the development of a system to study the replication of the virus that causes hepatitis C virus and for use of this system to revolutionize the treatment of this chronic, often lethal disease.

Allostatic load (AL) is a complex clinical construct, providing a unique window into the cumulative impact of stress. However, due to its inherent complexity, AL presents two major measurement challenges to conventional statistical modeling (the field's dominant methodology): it is comprised of a complex causal network of bioallostatic systems, represented by an even larger set of dynamic biomarkers; and, it is situated within a web of antecedent socioecological systems, linking AL to differences in health outcomes and disparities. To address these challenges, we employed case-based computational modeling (CBM), which allowed us to make four advances: (1) we developed a multisystem, 7-factor (20 biomarker) model of AL's network of allostatic systems; (2) used it to create a catalog of nine different clinical AL profiles (causal pathways); (3) linked each clinical profile to a typology of 23 health outcomes; and (4) explored our results (post hoc) as a function of gender, a key socioecological factor. In terms of highlights, (a) the Healthy clinical profile had few health risks; (b) the pro-inflammatory profile linked to high blood pressure and diabetes; (c) Low Stress Hormones linked to heart disease, TIA/Stroke, diabetes, and circulation problems; and (d) high stress hormones linked to heart disease and high blood pressure. Post hoc analyses also found that males were overrepresented on the High Blood Pressure (61.2%), Metabolic Syndrome (63.2%), High Stress Hormones (66.4%), and High Blood Sugar (57.1%); while females were overrepresented on the Healthy (81.9%), Low Stress Hormones (66.3%), and Low Stress Antagonists (stress buffers) (95.4%) profiles. (C) 2015 Wiley Periodicals, Inc.

Outcome measures of IVF success, which account for effectiveness of IVF and perinatal outcome risks, have recently been described. The association between number of embryos transferred in average and poor-prognosis IVF patients, and the chances of having good or poor IVF and perinatal outcomes, was investigated. Good IVF and perinatal outcome was defined as the birth of a live, term, normal-weight infant (>= 2500 g). Poor IVF and perinatal outcome was defined as no live birth or birth of a very low weight neonate (<1500 g) or severe prematurity (birth at <32 weeks gestation). Each neonate was analysed as a separate outcome. A total of 713 IVF cycles in 504 average and poor-prognosis patients from January 2010 to December 2013 were identified. The odds of having good IVF and perinatal outcomes increased by 28% for each additional embryo transferred. The odds of poor IVF and perinatal outcome decreased by 32% with an additional embryo transferred. The likelihood of live birth with good perinatal outcome in average-and poor-prognosis patients after IVF increases with additional embryos being transferred. These data add to recently reported evidence in favour of multiple embryo transfer in older women and those with average or poor IVF prognosis. (C) 2016 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

A vaccine that elicits broadly neutralizing antibodies (bNAbs) against HIV-1 is likely to be protective, but this has not been achieved. To explore immunization regimens that might elicit bNAbs, we produced and immunized mice expressing the predicted germline PGT121, a bNAb specific for the V3-loop and surrounding glycans on the HIV-1 spike. Priming with an epitope-modified immunogen designed to activate germline antibody-expressing B cells, followed by ELISA-guided boosting with a sequence of directional immunogens, native-like trimers with decreasing epitope modification, elicited heterologous tier-2-neutralizing responses. In contrast, repeated immunization with the priming immunogen did not. Antibody cloning confirmed elicitation of high levels of somatic mutation and tier-2-neutralizing antibodies resembling the authentic human bNAb. Our data establish that sequential immunization with specifically designed immunogens can induce high levels of somatic mutation and shepherd antibody maturation to produce bNAbs from their inferred germline precursors.

The intestinal microbiome modulates host susceptibility to enteric pathogens, but the specific protective factors and mechanisms of individual bacterial species are not fully characterized. We show that secreted antigen A (SagA) from Enterococcus faecium is sufficient to protect Caenorhabditis elegans against Salmonella pathogenesis by promoting pathogen tolerance. The NlpC/p60 peptidoglycan hydrolase activity of SagA is required and generates muramyl-peptide fragments that are sufficient to protect C. elegans against Salmonella pathogenesis in a tol-1-dependent manner. SagA can also be heterologously expressed and secreted to improve the protective activity of probiotics against Salmonella pathogenesis in C. elegans and mice. Our study highlights how protective intestinal bacteria can modify microbial-associated molecular patterns to enhance pathogen tolerance.

The expression of extracellular matrix protein periostin (POSTN) was attenuated in Med1(-/-) mouse embryonic fibroblasts (MEFs), which exhibited a decreased capability to support hematopoietic progenitor cells (HPCs) in vitro. When bone marrow (BM) cells were cocultured with mitomycin C-treated Med1(+/+) MEFs, or OP-9 or MS-5 BM stromal cells, in the presence of anti-POSTN antibody, the growth of BM cells and number of long-term culture-initiating cells (LTC-ICs) were attenuated. When BM cells were cocultured with Med1(-/-) MEFs in the presence of recombinant POSTN, the growth of BM cells and the number of LTC-ICs were restored. Moreover, antibody-mediated blockage of stromal cells-derived POSTN markedly reduced the growth and cobblestone formation, a leukemic stem cell feature, of stromal cell dependent MB-1 myeloblastoma cells. POSTN was expressed both in BM cells and variably in different BM stromal cells. Expression in the latter cells was increased by physical interaction with hematopoietic cells. The receptor for POSTN, integrin alpha v beta 3, was expressed abundantly in BM stromal cells. The addition of recombinant POSTN to BM stromal cells induced intracellular signaling downstream of integrin alpha v beta 3. These results suggest that stromal cell POSTN supports both normal HPCs and leukemia-initiating cells in vitro, at least in part, indirectly by acting on stromal cells in an autocrine or paracrine manner. (C) 2016 Elsevier Inc. All rights reserved.

The level of activity of many animals including humans rises and falls with a period of similar to 24 hours. The intrinsic biological oscillator that gives rise to this circadian oscillation is driven by a molecular feedback loop with an approximately 24 hour cycle period and is influenced by the environment, most notably the light: dark cycle. In addition to the circadian oscillations, behavior of many animals is influenced by multiple oscillations occurring at fasterultradian-time scales. These ultradian oscillations are also thought to be driven by feedback loops. While many studies have focused on identifying such ultradian oscillations, less is known about how the ultradian behavioral oscillations interact with each other and with the circadian oscillation. Decoding the coupling among the various physiological oscillators may be important for understanding how they conspire together to regulate the normal activity levels, as well in disease states in which such rhythmic fluctuations in behavior may be disrupted. Here, we use a wavelet-based cross-frequency analysis to show that different oscillations identified in spontaneous mouse behavior are coupled such that the amplitude of oscillations occurring at higher frequencies are modulated by the phase of the slower oscillations. The patterns of these interactions are different among different individuals. Yet this variability is not random. Differences in the pattern of interactions are confined to a low dimensional subspace where different patterns of interactions formclusters. These clusters expose the differences among individuals-males and females are preferentially segregated into different clusters. These sex-specific features of spontaneous behavior were not apparent in the spectra. Thus, our methodology reveals novel aspects of the structure of spontaneous animal behavior that are not observable using conventional methodology.

In Texas, Arizona, and New Mexico, colonias refer to unincorporated rural settlements along the U.S. Mexico border. Colonias lack governance and public services normally provided by local government (Ward, 1999). Residents typically rely on well water or hauled water stored in above-ground containers. This study attempted to quantify and compare water-related perceptions and practices of colonia residents. No significant differences were observed between colonia residents using well water versus hauled-stored water for water quality perceptions and water use practices. Most, however, had negative perceptions of their water supply; a majority perceived daily water supplies as not potable. Significant paradoxical discrepancies between perceptions and practice were identified. This study adds to a small but growing literature on subjective dimensions of quality of life indicators for colonia residents. Additional studies are needed to quantify the type and level of health risks posed by compromised water supplies for this vulnerable population. Understanding differences in perceptions and practices associated with water sources could help to identify which subpopulations of colonia residents are in greatest need of water infrastructure or remediation.