Recent studies indicate that mineral nanoparticles (NPs) form spontaneously in human body fluids. These biological NPs represent mineral precursors that are associated with ectopic calcifications seen in various human diseases. However, the parameters that control the formation of mineral NPs and their possible effects on human cells remain poorly understood. Here a nanomaterial approach to study the formation of biomimetic calcium phosphate NPs comparable to their physiological counterparts is described. Particle sizing using dynamic light scattering reveals that serum and ion concentrations within the physiological range yield NPs below 100 nm in diameter. While the particles are phagocytosed by macrophages in a size-independent manner, only large particles or NP aggregates in the micrometer range induce cellular responses that include production of mitochondrial reactive oxygen species, caspase-1 activation, and secretion of interleukin-1β (IL-1β). A comprehensive proteomic analysis reveals that the particle-bound proteins are similar in terms of their identity and number, regardless of particle size, suggesting that protein adsorption is independent of particle size and curvature. In conclusion, the conditions underlying the formation of mineralo-protein particles are similar to the ones that form in vivo. While mineral NPs do not activate immune cells, they may become pro-inflammatory and contribute to pathological processes once they aggregate and form larger mineral particles.

Fengycin, a lipopeptidic antibiotic, is synthesized nonribosomally by five fengycin synthetases (FenC, FenD, FenE, FenA, and FenB) in Bacillus subtilis F29-3. This work demonstrates that these fengycin synthetases interlock to form a chain, which coils into a 14.5-nm structure. In this chain, fengycin synthetases are linked in the order FenC-FenD-FenE-FenA-FenB by interactions between the C-terminal region of an upstream enzyme and the N-terminal region of its downstream partner enzyme, with their amino acid activation modules arranged colinearly with the amino acids in fengycin. This work also reveals that fengycin is synthesized on this fengycin synthetase chain, explaining how fengycin is synthesized efficiently and accurately. The results from this investigation demonstrate that forming a peptide synthetase complex is crucial to nonribosomal peptide synthesis.

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The spontaneous formation of serum-derived NPs and their internalization by cells may have overlooked effects on cultured cells in vitro as well as potential pathophysiological consequences in vivo.

Background With the development of laser‐assisted platforms, the outcomes of cataract surgery have been improved by automating several procedures. The cataract‐extraction step continues to be manually performed, but due to deficiencies in sensing capabilities, surgical complications such as posterior capsule rupture and incomplete cataract removal remain. Methods An optical coherence tomography (OCT) system is integrated into our intraocular robotic interventional surgical system (IRISS) robot. The OCT images are used for preoperative planning and intraoperative intervention in a series of automated procedures. Real‐time intervention allows surgeons to evaluate the progress and override the operation. Results The developed system was validated by performing lens extraction on 30 postmortem pig eyes. Complete lens extraction was achieved on 25 eyes, and “almost complete” extraction was achieved on the remainder due to an inability to image small lens particles behind the iris. No capsule rupture was found. Conclusion The IRISS successfully demonstrated semiautomated OCT‐guided lens removal with real‐time supervision and intervention.

BRCA1-associated protein 2 (BRAP2) is known to interact with the kinase suppressor of Ras 1 (KSR1), inhibiting the ERK signal transduction cascade. This study found that an Epstein-Barr virus (EBV) immediate-early protein, Rta, is a binding partner of BRAP2 in yeast and confirmed the binding in vitro by a glutathione S-transferase pull-down assay and in vivo by coimmunoprecipitation in 293(maxi-EBV) cells. Binding studies also showed that Rta and KSR1 interacted with the C-terminal 202 aa region in BRAP2. Additionally, Rta appeared to prevent the binding of KSR1 to BRAP2, activating the ERK signal transduction pathway and the transcription of an EBV immediate-early gene, BZLF1. Activation of the ERK signal transduction pathway by Rta may be critical for the maintenance of the lytic state of EBV. INTRODUCTIONEpstein-Barr virus (EBV) is a human herpesvirus that infects lymphoid and epithelial cells. Although EBV infection is commonly asymptomatic, infection by this virus also causes infectious mononucleosis (Diehl et al., 1968) and is closely associated with many neoplastic disorders (Einhorn et al., 1970;Gunven et al., 1970;Johansson et al., 1970;Klein et al., 1970). Although EBV typically remains latent after infection of B lymphocytes, the virus must enter a lytic cycle to produce virus particles. During the onset of the lytic cycle, the virus expresses the proteins Rta and Zta, encoded by BRLF1 and BZLF1, respectively, to activate the genes required for the viral lytic cycle (Chevallier-Greco et al., 1986;Chiu et al., 2007;Feederle et al., 2000;Granato et al., 2006;Hardwick et al., 1988;Lu et al., 2006). Although the exact means by which the EBV lytic cycle is activated in vivo is unknown, activation in vitro occurs after latently infected cells are exposed to 12-Otetradecanoylphorbol-13-acetate (TPA), calcium ionophores, transforming growth factor (TGF)-b1 or anti-IgG (Daibata et al., 1990; Faggioni et al., 1986;zur Hausen et al., 1978). TPA, anti-IgG and TGF-b1 are known to activate the ERK signal transduction pathway (Fahmi et al., 2000;Fenton & Sinclair, 1999;Gao et al., 2001;Satoh et al., 1999), which ultimately activates transcription of BZLF1 and the EBV lytic cycle (Borras et al., 1996;Flemington & Speck, 1990).It is known that EBV must express Zta to activate its lytic genes (Chevallier-Greco et al., 1986;Chiu et al., 2007;Feederle et al., 2000). Earlier studies have established that Rta upregulates transcription of the Zta gene, BZLF1 (Adamson et al., 2000;Ragoczy et al., 1998;Zalani et al., 1996). This activation is associated with activation of the p38 and JNK signal transduction pathway, causing the phosphorylation of ATF1/2 and the activation of transcription through an ATF1/ 2 site in the ZII region of the promoter (Adamson et al., 2000). However, the exact means by which Rta activates these signal transduction cascades is unknown. In this study, we used a yeast two-hybrid analysis to show that Rta interacts with BRCA1-associated protein 2 (BRAP2, also known as IMP), a protein that is known to i...

Background: Stack-of-radial multiecho gradient-echo MRI is promising for free-breathing liver R * 2 quantification and may benefit children. Purpose: To validate stack-of-radial MRI with self-gating motion compensation in phantoms, and to evaluate it in children. Study Type: Prospective. Phantoms: Four vials with different R * 2 driven by a motion stage. Subjects: Sixteen pediatric patients with suspected nonalcoholic fatty liver disease or steatohepatitis (five females, 13 ± 4 years, body mass index 29.2 ± 8.6 kg/m 2). Field Strength/Sequences: Stack-of-radial, and 2D and 3D Cartesian multiecho gradient-echo sequences at 3T. Assessment: Ungated and gated stack-of-radial proton density fat fraction (PDFF) and R * 2 maps were reconstructed without and with self-gating motion compensation. Stack-of-radial R * 2 measurements of phantoms without and with motion were validated against reference 2D Cartesian results of phantoms without motion. In subjects, free-breathing stack-ofradial and reference breath-hold 3D Cartesian were acquired. Subject inclusion for statistical analysis and region of interest placement were determined independently by two observers. Statistical Tests: Phantom results were fitted with a weighted linear model. Demographic differences between excluded and included subjects were tested by multivariate analysis of variance. PDFF and R * 2 measurements were compared using Bland-Altman analysis. Interobserver agreement was assessed by the intraclass correlation coefficient (ICC). Results: Ungated stack-of-radial R * 2 inside moving phantom vials showed a significant positive bias of 64.3 s −1 (P < 0.00001), unlike gated results (P > 0.31). Subject inclusion decisions for statistical analysis from two observers were consistent. No significant differences were found between four excluded and 12 included subjects (P = 0.14). Compared to breath-hold Cartesian, ungated and gated free-breathing stack-of-radial exhibited mean R * 2 differences of 18.5 s −1 and 3.6 s −1. Mean PDFF differences were 1.1% and 1.0% for ungated and gated measurements, respectively. Interobserver agreement was excellent (ICC for PDFF = 0.99, ICC for R * 2 = 0.90; P < 0.0003).

Semi-automated lens extraction procedures were evaluated using the Intraocular Interventional Surgical System (IRISS) on 30 post-mortem pig eyes. No posterior capsule rupture was reported and complete lens removal was achieved in 25 trials without significant surgical complications.