Visualizing Escherichia coli Sub-Cellular Structure Using Sparse Deconvolution Spatial Light Interference Tomography

Studying the 3D sub-cellular structure of living cells is essential to our understanding of biological function. However, tomographic imaging of live cells is challenging mainly because they are transparent, i.e., weakly scattering structures. Therefore, this type of imaging has been implemented largely using fluorescence techniques. While confocal fluorescence imaging is a common approach to achieve sectioning, it requires fluorescence probes that are often harmful to the living specimen. On the other hand, by using the intrinsic contrast of the structures it is possible to study living cells in a non-invasive manner. One method that provides high-resolution quantitative information about nanoscale structures is a broadband interferometric technique known as Spatial Light Interference Microscopy (SLIM). In addition to rendering quantitative phase information, when combined with a high numerical aperture objective, SLIM also provides excellent depth sectioning capabilities. However, like in all linear optical systems, SLIM's resolution is limited by diffraction. Here we present a novel 3D field deconvolution algorithm that exploits the sparsity of phase images and renders images with resolution beyond the diffraction limit. We employ this label-free method, called deconvolution Spatial Light Interference Tomography (dSLIT), to visualize coiled sub-cellular structures in E. coli cells which are most likely the cytoskeletal MreB protein and the division site regulating MinCDE proteins. Previously these structures have only been observed using specialized strains and plasmids and fluorescence techniques. Our results indicate that dSLIT can be employed to study such structures in a practical and non-invasive manner

Nonlinear Time Series Analysis of Nodulation Factor Induced Calcium Oscillations: Evidence for Deterministic Chaos?

Legume plants form beneficial symbiotic interactions with nitrogen fixing bacteria (called rhizobia), with the rhizobia being accommodated in unique structures on the roots of the host plant. The legume/rhizobial symbiosis is responsible for a significant proportion of the global biologically available nitrogen. The initiation of this symbiosis is governed by a characteristic calcium oscillation within the plant root hair cells and this signal is activated by the rhizobia. Recent analyses on calcium time series data have suggested that stochastic effects have a large role to play in defining the nature of the oscillations. The use of multiple nonlinear time series techniques, however, suggests an alternative interpretation, namely deterministic chaos. We provide an extensive, nonlinear time series analysis on the nature of this calcium oscillation response. We build up evidence through a series of techniques that test for determinism, quantify linear and nonlinear components, and measure the local divergence of the system. Chaos is common in nature and it seems plausible that properties of chaotic dynamics might be exploited by biological systems to control processes within the cell. Systems possessing chaotic control mechanisms are more robust in the sense that the enhanced flexibility allows more rapid response to environmental changes with less energetic costs. The desired behaviour could be most efficiently targeted in this manner, supporting some intriguing speculations about nonlinear mechanisms in biological signaling

Chemotherapy-induced hyaluronan production: a novel chemoresistance mechanism in ovarian cancer

Background: Hyaluronan (HA) an important component of the extracellular matrix, has been linked to tumor progression and drug resistance in several malignancies. However, limited data is available for ovarian cancer. This study investigated the role of hyaluronan (HA) and a potential link between the HA-CD44 pathway and membrane ATP binding cassette (ABC) transporter proteins in ovarian cancer chemoresistance. Methods: We investigated the ability of HA to block the cytotoxic effects of the chemotherapy drug carboplatin, and to regulate the expression of ABC transporters in ovarian cancer cells. We also examined HA serum levels in ovarian cancer patients prior to and following chemotherapy and assessed its prognostic relevance. Results: HA increased the survival of carboplatin treated ovarian cancer cells expressing the HA receptor, CD44 (OVCAR-5 and OV-90). Carboplatin significantly increased expression of HAS2, HAS3 and ABCC2 and HA secretion in ovarian cancer cell conditioned media. Serum HA levels were significantly increased in patients following platinum based chemotherapy and at both 1st and 2nd recurrence when compared with HA levels prior to treatment. High serum HA levels (>50 μg/ml) prior to chemotherapy treatment were associated with significantly reduced progression-free (P = 0.014) and overall survival (P = 0.036). HA production in ovarian cancer cells was increased in cancer tissues collected following chemotherapy treatment and at recurrence. Furthermore HA treatment significantly increased the expression of ABC drug transporters (ABCB3, ABCC1, ABCC2, and ABCC3), but only in ovarian cancer cells expressing CD44. The effects of HA and carboplatin on ABC transporter expression in ovarian cancer cells could be abrogated by HA oligomer treatment. Importantly, HA oligomers increased the sensitivity of chemoresistant SKOV3 cells to carboplatin. Conclusions: Our findings indicate that carboplatin chemotherapy induces HA production which can contribute to chemoresistance by regulating ABC transporter expression. The HA-CD44 signaling pathway is therefore a promising target in platinum resistant ovarian cancer.Carmela Ricciardelli, Miranda P Ween, Noor A Lokman, Izza A Tan, Carmen E Pyragius, and Martin K Oehle

Recent advances reveal IL-8 signaling as a potential key to targeting breast cancer stem cells

Breast cancer stem-like cells (CSCs) are an important therapeutic target as they are purported to be responsible for tumor initiation, maintenance, metastases, and disease recurrence. Interleukin-8 (IL-8) is upregulated in breast cancer compared with normal breast tissue and is associated with poor prognosis. IL-8 is reported to promote breast cancer progression by increasing cell invasion, angiogenesis, and metastases and is upregulated in HER2-positive cancers. Recently, we and others have established that IL-8 via its cognate receptors, CXCR1 and CXCR2, is also involved in regulating breast CSC activity. Our work demonstrates that in metastatic breast CSCs, CXCR1/2 signals via transactivation of HER2. Given the importance of HER2 in breast cancer and in regulating CSC activity, a pathway driving the activation of these receptors would have important biological and clinical consequences, especially in tumors that express high levels of IL-8 and other CXCR1/2-activating ligands. Here, we review the IL-8 signaling pathway and the role of HER2 in maintaining an IL-8 inflammatory loop and discuss the potential of combining CXCR1/2 inhibitors with other treatments such as HER2-targeted therapy as a novel approach to eliminate CSCs and improve patient survival

A field study on monitoring of blasting-induced vibrations of tunnels and its possible use for in-situ stress interferences

ISRM International Symposium - EUROCK 2016 -- 29 August 2016 through 31 August 2016 -- -- 144475The authors performed ground motion measurements during blasting operations at several tunnels in association of rehabilitating the intercity roadways in Turkey in Zonguldak. The authors have been monitoring the blasting-induced vibrations in adjacent tunnel near at Üzülmez tunnel excavated through an urbanized area to see the effects of blasting on adjacent tunnels and ground surface. In this study, the outcomes of monitoring of vibrations in tunnels and at ground surface are presented and some empirical attenuation relations used for assessing the effects of blasting on the adjacent structures are proposed. The authors also attempted to infer in-situ stresses using the damage of blasted-holes. The authors utilized the fault striation method (Aydan 2000) and blasted hole damage method (BHMD) (Aydan 2013). Aydan (2013) proposed a method to estimate the stress state from the damage zone around blasted holes. This method was applied to damage zone around blasted holes and some stress inferences made for the tunnel face. Estimations of in-situ stress estimations from different methods were compared. Finally, the outcomes of the field monitoring of blasting-induced vibrations of tunnels and their environmental effects are presented and discussed. © 2016 Taylor & Francis Group, LondonBülent Ecevit Üniversitesi :2013-981-50330-03The authors sincerely acknowledge 15th Regional Section of Turkish General Directorate of Highways (KGM) for permission to publish this article, Bülent Ecevit University for financial support to the Scientific Research Unit (Project No:2013-981-50330-03). Furthermore, the help given by KGM Control Engineer Suat Cüre, Selçuk Genç of ENEZ Construction Project Director, and Prof.Aydın Bilgin of Middle East Technical University during field measurements and investigations

Pull-driven construction of high-rise apartment buildings

Construction of high-rise apartment buildings is made complex by the myriad possibilities for clients to adapt their apartments to suit their individual needs and preferences; traditional construction planning practice of progressing upwards from floor to floor breaks down in the face of the arbitrary sequence in which clients finalize their decisions. The results are long cycle times for delivery of completed apartments and corollary high levels of work in progress (WIP), budget and schedule overruns, and general dissatisfaction with the process on the part of the contractors, subcontractors and the clients. This paper presents a management model that applies lean thinking to this problem. The model was first formulated in theory, then tested using a management simulation game, and subsequently developed for practical application by a dedicated team composed of university researchers and construction company personnel. It is now being tested in a large construction company

Preparation and photoluminescence properties of aluminate phosphors produced by combustion synthesis

WOS:000454462500009PubMed:30248589In this work, Eu, Nd co-doped MAl2O4:Eu, Nd (M = Ca, Sr, Ba) phosphors were synthesized at low temperatures (550 degrees C) by the combustion method. The crystallinity of the phosphors was monitored by X-ray diffraction (XRD) and the morphology was examined by scanning electron microscope (SEM). Synthesis of phosphors, the effect of lanthanide concentrations on light emission intensity and duration investigated by using photoluminescence (PL) measurements. Narrow orange-red emissions from 500 to 750 nm in the PL spectra are assigned to D-5(0) -> F-7(j)) (j = 0,1,2,3,...) transitions of Eu3+ ion. In contrast, the broad luminescence band of the samples in the range of 400-500 rim are attributed to the 5d-4 f transitions of Eu3+ ion in the same host materials. Investigated the effects of radiation on the severity of the trap depths of these structures. The decay curves of these phosphors show how long the phosphors are attenuated. Thermoluminescence (TL) glow curves have been recorded from room temperature to 300 degrees C at a constant heating rate of 1 degrees C/s after preheat process at 130 degrees C for 10 s using lexsyg smart TL/OSL reader. Nd3+ trap levels can be thought of as the lanthanide element that causes long composition in the phosphorescence structure at room temperature