Setting the basis for transient DNA transformation and transformant selection in the red macroalga Gracilariopsis lemaneiformis

Gracilariopsis lemaneiformis (Gp. lemaneiformis) is an economically important agar-producing red alga applicable in the food and cosmetic industries. The genetic knowledge of this species is, however, limited, and genetic tools for studying and engineering it are lacking. This has limited the understanding of its developmental genetics and hindered the development of new strains, and developing genetic tools would allow to tackle these problems. Here, transient DNA transformation via microparticle bombardment is reported for the first time in this species, as well as efficient exogenous gene expression driven by the CaMV35S promoter, the endogenous GlAct1 promoter, and the Pyropia yezoensis PyAct1 promoter in the transformed branches. Moreover, the Blue Fluorescent Protein (BFP) is demonstrated to be a suitable reporter gene for studies in Gp. lemaneiformis. Screening of antibiotic sensitivity is needed for the development of transient DNA transformation, and selection of transformants is also reported in the alga. Hygromycin B (Hyg) is determined to be the most effective antibiotic for Gp. lemaneiformis selection. The Hyg resistance gene driven by the CaMV35S promoter is shown to confer resistance to Hyg at a concentration of 1 mg.ml-1, but no transformed individual could be regenerated so far. These results are promising for future refining of the experimental conditions, for instance, by using different promoters and developing techniques for facilitating the penetration of the DNA in the cells

Distributed Power Allocation for Sink-Centric Clusters in Multiple Sink Wireless Sensor Networks

Due to the battery resource constraints, saving energy is a critical issue in wireless sensor networks, particularly in large sensor networks. One possible solution is to deploy multiple sink nodes simultaneously. Another possible solution is to employ an adaptive clustering hierarchy routing scheme. In this paper, we propose a multiple sink cluster wireless sensor networks scheme which combines the two solutions, and propose an efficient transmission power control scheme for a sink-centric cluster routing protocol in multiple sink wireless sensor networks, denoted as MSCWSNs-PC. It is a distributed, scalable, self-organizing, adaptive system, and the sensor nodes do not require knowledge of the global network and their location. All sinks effectively work out a representative view of a monitored region, after which power control is employed to optimize network topology. The simulations demonstrate the advantages of our new protocol

Concurrent inhibition of FAK/SRC and MEK overcomes MEK inhibitor resistance in Neurofibromatosis Type I related malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumors (MPNST) are aggressive soft-tissue sarcomas which lack effective drugs. Loss of the RAS GTPase-activating protein NF1 and subsequent overactivation of mitogen-activated protein kinase kinase (MAPK) signaling exist nearly uniformly in MPNST, making MAPK inhibition a promising therapeutic intervention. However, the efficacy of MEK inhibitor (MEKi) monotherapy was limited in MPNST and the relative mechanisms remained largely unexplored. In this study, we generated three MEKi-resistant cell models and investigated the mechanisms of MEKi resistance using high-throughput transcriptomic sequencing. We discovered that cell apoptosis and cell cycle arrest induced by MEKi were rescued in MEKi-resistant cells and the upregulation of LAMA4/ITGB1/FAK/SRC signaling conferred resistance to MEKi. In addition, concurrent inhibition of MAPK signaling and FAK/SRC cascade could sensitize MPNST cells to MEKi. Our findings provide potential solutions to overcome MEKi resistance and effective combination therapeutic strategies for treating MPNSTs

Cell Membrane Is Impaired, Accompanied by Enhanced Type III Secretion System Expression in Yersinia pestis Deficient in RovA Regulator

BACKGROUND: In the enteropathogenic Yersinia species, RovA regulates the expression of invasin, which is important for enteropathogenic pathogenesis but is inactivated in Yersinia pestis. Investigation of the RovA regulon in Y. pestis at 26 °C has revealed that RovA is a global regulator that contributes to virulence in part by the direct regulation of psaEFABC. However, the regulatory roles of RovA in Y. pestis at 37 °C, which allows most virulence factors in mammalian hosts to be expressed, are still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: The transcriptional profile of an in-frame rovA mutant of Y. pestis biovar Microtus strain 201 was analyzed under type III secretion system (T3SS) induction conditions using microarray techniques, and it was revealed that many cell-envelope and transport/binding proteins were differentially expressed in the ΔrovA mutant. Most noticeably, many of the T3SS genes, including operons encoding the translocon, needle and Yop (Yersinia outer protein) effectors, were significantly up-regulated. Analysis of Yop proteins confirmed that YopE and YopJ were also expressed in greater amounts in the mutant. However, electrophoresis mobility shift assay results demonstrated that the His-RovA protein could not bind to the promoter sequences of the T3SS genes, suggesting that an indirect regulatory mechanism is involved. Transmission electron microscopy analysis indicated that there are small loose electron dense particle-like structures that surround the outer membrane of the mutant cells. The bacterial membrane permeability to CFSE (carboxyfluorescein diacetate succinimidyl ester) was significantly decreased in the ΔrovA mutant compared to the wild-type strain. Taken together, these results revealed the improper construction and dysfunction of the membrane in the ΔrovA mutant. CONCLUSIONS/SIGNIFICANCE: We demonstrated that the RovA regulator plays critical roles in the construction and functioning of the bacterial membrane, which sheds considerable light on the regulatory functions of RovA in antibiotic resistance and environmental adaptation. The expression of T3SS was upregulated in the ΔrovA mutant through an indirect regulatory mechanism, which is possibly related to the altered membrane construction in the mutant

Femtosecond photoelectron imaging of NO at 410 nm

The simultaneous measurement of the photoelectron kinetic energy and angular distributions of NO were performed as a function of 410 nm laser intensities by femtosecond photoelectron imaging. The photoelectron kinetic energies are nearly independent of the laser intensities. The insensitivity of the photoelectron kinetic energy to the laser peak intensity suggests that peaks in the photoelectron spectra result from Freemen resonance, characteristic of the occurrence of real population on the intermediate states. The relative amplitudes of photoelectron peaks indicate that lower laser intensities emphasize the resonant population while higher laser intensities favor nonresonant population. The A(2) Sigma(+)(nu = 2) state can be weakly coupled to the B-2 Pi(nu = 4) state, results in a small part of population on B-2 Pi(nu = 4) state transferred from A(2) Sigma(+)(nu = 2) state. The strong field effect leads to more anisotropy of ATI than that of non-ATI. The modulation of populations in electronic states can be achieved by adjusting laser peak intensities. The results can provide some important basis for realizing quantum manipulation of molecules experimentally. (C) 2018 Elsevier GmbH. All rights reserved

Modified duct-to-mucosa versus conventional pancreaticoenterostomy for pancreaticoduodenectomy: a retrospective cohort study based on propensity score matching analysis

Abstract Background Clinically relevant postoperative pancreatic fistula (CR-POPF) remains the most common neopathy after pancreatoduodenectomy (PD). An ideal pancreaticoenterostomy (PE) which can effectively reduce the incidence of CR-POPF and its potential neopathy is needed. We aimed to assess the efficacy of our modified duct-to-mucosa PE in the PD. Method From January 2011 to December 2017, 233 consecutive patients with PD were retrospectively included from Shenzhen People’s Hospital. After propensity score matching (PSM), there were 82 patients in both the modified duct-to-mucosa PE group (group A) and the conventional end-to-side inserting PE group (group B), respectively. The clinical course and the incidence of postoperative neopathy were compared between groups. Logistic regression method was utilized to analyze the association between PE approach and CR-POPF. Results The PE time was shorter in group A (9.3 ± 1.8 min vs. 21.5 ± 2.8 min, P  II) [7.3% (5/82) vs. 17.1% (14/82), P = 0.028] and incidence of CR-POPF [1.2% (1/82) vs. 19.5% (12/82), P < 0.001] than the group B. Our modified duct-to-mucosa PE technique was associated with a reduced risk for CR-POPF (OR, 0.11 [95% CI, 0.02–0.57]; P = 0.009) as compared with the conventional end-to-side inserting PE. Conclusion Compared with conventional end-to-side inserting PE, our modified duct-to-mucosa PE technique can effectively reduce the incidences of postoperative neopathy and CR-POPF. Trial registration Researchregistry3877. Registered 24 March 2018. Retrospectively registered

influenceoffemtosecondlaserparametersonautlertownessplittingofthreelevelladdermolecules

利用三态模型和含时波包法，研究了K2分子在强飞秒泵浦一探测激光场中泵浦／探测场强、波长对光电子能谱Autler—Townes（AT）分裂的影响．通过分别改变两激光场的场强或者波长预测AT峰移和间距，并且首次量化了AT分裂的峰移和间距．光电子能谱在共振时显示为对称双峰，失谐时为非对称双峰。AT分裂间距随泵浦场强增大而增大，但不因探测场强改变而改变

A segmented regime-switching model with its application to stock market indices

This paper evaluates the ability of a Markov regime-switching log-normal (RSLN) model to capture the time-varying features of stock return and volatility. The model displays a better ability to depict a fat tail distribution as compared with using a log-normal model, which means that the RSLN model can describe observed market behavior better. Our major objective is to explore the capability of the model to capture stock market behavior over time. By analyzing the behavior of calibrated regime-switching parameters over different lengths of time intervals, the change-point concept is introduced and an algorithm is proposed for identifying the change-points in the series corresponding to the times when there are changes in parameter estimates. This algorithm for identifying change-points is tested on the Standard and Poor's 500 monthly index data from 1971 to 2008, and the Nikkei 225 monthly index data from 1984 to 2008. It is evident that the change-points we identify match the big events observed in the US stock market and the Japan stock market (e.g., the October 1987 stock market crash), and that the segmentations of stock index series, which are defined as the periods between change-points, match the observed bear-bull market phases.algorithm, change-point, log-normal, log-returns, Markov process, maximum likelihood estimation, segmented regime-switching model, stock market index, time series,