Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Infrared-Visible Image Fusion Based on Semantic Guidance and Visual Perception

Infrared-visible fusion has great potential in night-vision enhancement for intelligent vehicles. The fusion performance depends on fusion rules that balance target saliency and visual perception. However, most existing methods do not have explicit and effective rules, which leads to the poor contrast and saliency of the target. In this paper, we propose the SGVPGAN, an adversarial framework for high-quality infrared-visible image fusion, which consists of an infrared-visible image fusion network based on Adversarial Semantic Guidance (ASG) and Adversarial Visual Perception (AVP) modules. Specifically, the ASG module transfers the semantics of the target and background to the fusion process for target highlighting. The AVP module analyzes the visual features from the global structure and local details of the visible and fusion images and then guides the fusion network to adaptively generate a weight map of signal completion so that the resulting fusion images possess a natural and visible appearance. We construct a joint distribution function between the fusion images and the corresponding semantics and use the discriminator to improve the fusion performance in terms of natural appearance and target saliency. Experimental results demonstrate that our proposed ASG and AVP modules can effectively guide the image-fusion process by selectively preserving the details in visible images and the salient information of targets in infrared images. The SGVPGAN exhibits significant improvements over other fusion methods

Tumor vasculature-targeted recombinant mutated human TNF-α enhanced the antitumor activity of doxorubicin by increasing tumor vessel permeability in mouse xenograft models.

OBJECTIVE: Increasing evidence suggests that, when used in combination, tumor necrosis factor-α (TNF-α) synergizes with traditional chemotherapeutic drugs to exert a heightened antitumor effect. The present study investigated the antitumor efficacy of recombinant mutated human TNF-α specifically targeted to the tumor vasculature (RGD-rmhTNF-α) combined with the chemotherapeutic agent doxorubicin in 2 murine allografted tumor models. METHODS: Mice bearing hepatoma or sarcoma allografted tumors were treated with various doses of RGD-rmhTNF-α alone or in combination with doxorubicin (2 mg/kg). We then evaluated tumor growth and tumor vessel permeability as well as intratumoral levels of RGD-rmhTNF-α and doxorubicin. RESULTS: RGD-rmhTNF-α treatment enhanced the permeability of the tumor vessels and increased intratumoral doxorubicin levels. In addition, intratumoral RGD-rmhTNF-α levels were significantly higher than that of rmhTNF-α. In both of the tested tumor models, administering RGD-rmhTNF-α in combination with doxorubicin resulted in an enhanced antitumor response compared to either treatment alone. Double-agent combination treatment of doxorubicin with 50,000 IU/kg RGD-rmhTNF-α induced stronger antitumor effects on H22 allografted tumor-bearing mice than the single doxorubicin agent alone. Moreover, doxorubicin with 10,000 IU/kg RGD-rmhTNF-α synergized to inhibit tumor growth in S180 allografted tumor-bearing mice. CONCLUSIONS: These results suggest that targeted delivery of low doses of RGD-rmhTNF-α into the tumor vasculature increases the antitumor efficacy of chemotherapeutic drugs

Transcriptional regulation of epithelial-mesenchymal transition

It has become increasingly obvious that the notion of a terminally differentiated cell is likely a simplified concept. Epithelial-mesenchymal transition (EMT), during which epithelial cells assume a mesenchymal phenotype, is a key event occurring during normal development and pathological processes. Multiple extracellular stimuli and transcriptional regulators can trigger EMT, but how such distinct signaling pathways orchestrate the complex cellular events that facilitate EMT is not well understood. In this issue of the JCI, Venkov et al. report on their examination of fibroblasts resulting from EMT and describe a novel protein-DNA complex that is essential for transcription of fibroblast-specific protein 1 (FSP1) and sufficient to induce early EMT events (see the related article beginning on page 482). Collectively, their results suggest that this complex is an important regulator of the EMT transcriptome

Distribution of RGD-rmhTNF-α and rmhTNF-α in tumors and serum of S180-bearing ICR mice.

<p>Equimolar amounts of RGD-rmhTNF-α (5.89 µg/kg weight) and rmhTNF-α (5.52 µg/kg weight) were i.v. injected into the tail vein of S180 hepatoma-bearing ICR mice. TNF-α levels were detected in serum and tumor homogenates by ELISA at 5, 20, and 60 min post-dosing (n = 6 mice/time point. Data are represented as the mean ± SD from 3 experiments. Numbers above bars indicate relative fold changes between the groups.</p

Effect of RGD-rmhTNF-α on tumor vessel permeability, and the effect of doxorubicin combined with RGD-rmhTNF-α on the tumor-growth inhibition rate when administered via different routes.

<p>(A) RGD-rmhTNF-α increases tumor-vessel permeability. Mice-bearing S180 cells (n = 8/group) were treated with or without RGD-rmhTNF-α (0.1 mL, i.m.), followed 2 h later by administration of Evans Blue dye (0.1%, 0.2 mL, i.v.) or doxorubicin (2 mg/kg, i.p.). After 2 h, mice were sacrificed, tumors were excised, and the concentration of Evans blue or doxorubicin was measured within the tumor (µg/g tumor tissue). The relative increase in concentration was calculated and statistically analyzed (*<i>p</i><0.05, RGD-rmhTNF-α+Evans Blue or RGD-rmhTNF-α+doxorubicin compared with Evans Blue or doxorubicin alone, respectively). (B) The effect of RGD-rmhTNF-α combined with doxorubicin on tumor-growth inhibition rate was similar between the i.m. and i.p. administration routes of RGD-rmhTNF-α. Animals bearing S180 allografted tumors (n = 16/group,n = 24 in DOX alone group) were i.m. or i.p. treated every 2 days with various doses of RGD-rmhTNF-α combined with doxorubicin starting on day 10 after tumor implantation. Saline was used as negative control. Mice received a total of 6 consecutive treatments and were sacrificed; tumors were immediately excised and weighed. The inhibition rate was calculated based on the tumor growth of mice in the saline-treated group. Data are represented as the mean (%) ± SD from 3 experiments. (C) Picture showing tumors excised from mice used to calculate the data shown in B. 1, Saline; 2, DOX alone (2 mg/kg); 3–7, DOX+RGD-rmhTNFα (10,000, 22,360, 50,000, 111,800, and 250,000 IU/kg, respectively), i.m.; 8–12, DOX+RGD-rmhTNFα (10,000, 22,360, 50,000, 111,800, and 250,000 IU/kg, respectively), i.p.</p

Pericyte Depletion Results in Hypoxia-Associated Epithelial-to-Mesenchymal Transition and Metastasis Mediated by Met Signaling Pathway

The functional role of pericytes in cancer progression remains unknown. Clinical studies suggest that low numbers of vessel-associated pericytes correlated with a drop in overall survival of patients with invasive breast cancer. Using genetic mouse models or pharmacological inhibitors, pericyte depletion suppressed tumor growth but enhanced metastasis. Pericyte depletion was further associated with increased hypoxia, epithelial-to-mesenchymal transition (EMT), and Met receptor activation. Silencing of Twist or use of a Met inhibitor suppressed hypoxia and EMT/Met-driven metastasis. In addition, poor pericyte coverage coupled with high Met expression in cancer cells speculates the worst prognosis for patients with invasive breast cancer. Collectively, our study suggests that pericytes within the primary tumor microenvironment likely serve as important gatekeepers against cancer progression and metastasis.National Institutes of Health (U.S.) (NIH Grant CA125550)National Institutes of Health (U.S.) (NIH grant CA155370)National Institutes of Health (U.S.) (NIH Grant CA151925)National Institutes of Health (U.S.) (NIH Grant DK81576)National Institutes of Health (U.S.) (NIH Grant CA163191)National Institutes of Health (U.S.) (NIH grant DK55001)Champalimaud Foundation (Champalimaud metastasis programme)Champalimaud Foundation (Champalimaud investigator)National Institutes of Health (U.S.) (NRSA F32 Ruth Kirschstein Postdoctoral Fellowship from NIH/NIDDK (5F32DK082119-02))National Institutes of Health (U.S.) (NIH Research Training Grant in Gastroenterology (2T32DK007760-11))National Institutes of Health (U.S.) (NIH Research Training Grant in Cancer Biology (5T32CA081156-08))United States. Dept. of Defense (DoD Breast Cancer Research Predoctoral Traineeship Award (W81XWH-09-1-0008))National Institutes of Health (U.S.) (NIH Research Training Grant in Cardiovascular Medicine (5T32HL007374-30))United Negro College Fund/Merck (Postdoctoral Science Research Fellowship)National Institutes of Health (U.S.) (NIH supplemental grant (CA125550)