BackgroundNitrogen limitation can induce neutral lipid accumulation in microalgae, as well as inhibiting their growth. Therefore, to obtain cultures with both high biomass and high lipid contents, and explore the lipid accumulation mechanisms, we implemented nitrogen deprivation in a model diatom Phaeodactylum tricornutum at late exponential phase.ResultsNeutral lipid contents per cell subsequently increased 2.4-fold, both the number and total volume of oil bodies increased markedly, and cell density rose slightly. Transcriptional profile analyzed by RNA-Seq showed that expression levels of 1213 genes (including key carbon fixation, TCA cycle, glycerolipid metabolism and nitrogen assimilation genes) increased, with a false discovery rate cut-off of 0.001, under N deprivation. However, most light harvesting complex genes were down-regulated, extensive degradation of chloroplast membranes was observed under an electron microscope, and photosynthetic efficiency declined. Further identification of lipid classes showed that levels of MGDG and DGDG, the main lipid components of chloroplast membranes, dramatically decreased and triacylglycerol (TAG) levels significantly rose, indicating that intracellular membrane remodeling substantially contributed to the neutral lipid accumulation.ConclusionsOur findings shed light on the molecular mechanisms of neutral lipid accumulation and the key genes involved in lipid metabolism in diatoms. They also provide indications of possible strategies for improving microalgal biodiesel production.

Rhodopsin homeostasis is tightly coupled to rod photoreceptor cell survival and vision. Mutations resulting in the misfolding of rhodopsin can lead to autosomal dominant retinitis pigmentosa (adRP), a progressive retinal degeneration that currently is untreatable. Using a cell-based high-throughput screen (HTS) to identify small molecules that can stabilize the P23H-opsin mutant, which causes most cases of adRP, we identified a novel pharmacological chaperone of rod photoreceptor opsin, YC-001. As a non-retinoid molecule, YC-001 demonstrates micromolar potency and efficacy greater than 9-cis-retinal with lower cytotoxicity. YC-001 binds to bovine rod opsin with an EC50 similar to 9-cis-retinal. The chaperone activity of YC-001 is evidenced by its ability to rescue the transport of multiple rod opsin mutants in mammalian cells. YC-001 is also an inverse agonist that non-competitively antagonizes rod opsin signaling. Significantly, a single dose of YC-001 protects Abca4−/−Rdh8−/− mice from bright light-induced retinal degeneration, suggesting its broad therapeutic potential.

Patients with late-onset Tay-Sachs disease (LOTS) show characteristic abnormalities of saccades but normal afferent visual systems. Hypometria, transient decelerations, and premature termination of saccades suggest disruption of a "latch circuit" that normally inhibits pontine omnipause neurons, permitting burst neurons to discharge until the eye movement is completed. These measurable abnormalities of saccades provide a means to evaluate the effects of novel treatments for LOTS.

Rheumatoid arthritis (RA) is difficult to cure. Many methods have been used for its treatment, among which traditional Chinese medicine (TCM) has been considered as an important strategy. All of the three parts of TCM: Chinese herbs, acupuncture, and massage have been reported with varying degrees of therapeutic effects on RA. Also the mechanism exploration is under process. Many effective ingredients of anti-rheumatic Chinese herbs have been found to inhibit RA development and some of the effective ingredients have been verified. Furthermore, greatly enhanced life quality of RA patients was obtained using acupuncture and massage to relieve pain, expand joint motion and modulate emotion which mainly correlated with the possible modulation of immune system, nerve system, endocrine system, etc. Thus, a systemic review on the therapeutic effect of TCM on RA is necessary. In our paper, the current status of TCM application in the clinic for the therapy of RA was summarized accompanied with the related mechanism exploration using modern test facilities.

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Purpose The Diabetic Macular Edema Treated with Ozurdex (DMEO) Trial measured aqueous pro-permeability factors (PPFs) in diabetic macular edema (DME) patients before and after injection of dexamethasone implant or vascular endothelial growth factor (VEGF)-neutralizing protein and correlated changes in levels with changes in excess foveal thickness (EFT) to identify potential PPFs contributing to DME. Design Prospective, randomized cross-over clinical trial Methods Twenty DME patients randomized to dexamethasone implant or VEGF-neutralizing protein had aqueous taps and spectral domain-optical coherence tomography (SD-OCT) at baseline and every 4 weeks for 28 weeks. Aqueous levels of 55 vasoactive proteins were measured with protein array. Cross-over at week 16 provided changes in protein levels after each intervention in all 20 patients. Results After dexamethasone implant there was significant correlation between changes in levels of 13 vasoactive proteins with changes in EFT, including three known PPFs, angiopoietin-2 (r=0.40, p=0.001), hepatocyte growth factor (HGF, r=0.31, p=0.02), and endocrine gland-VEGF (EG-VEGF, r=0.43, p<0.001). Reduction of prolactin, insulin-like growth factor binding protein-3, and matrix metalloproteinase-9 correlated with edema reduction after injection of a VEGF-neutralizing protein as well as dexamethasone implant suggesting their modulation is likely secondary to changes in edema rather than causative. Conclusions Correlation of edema reduction with reduction in the PPFs angiopoietin-2, HGF, and EG-VEGF provides potential insight into the multi-factorial molecular mechanism by which dexamethasone implants reduce edema and suggest that additional study is needed to investigate the contributions of these 3 factor to chronic DME.

Objectives: To measure vertical and horizontal responses to optokinetic (OK) stimulation and investigate directional abnormalities of quick phases in progressive supranuclear palsy (PSP). Methods: Saccades and OK nystagmus were studied in six PSP patients, five with Parkinson's disease (PD), and 10 controls. The OK stimulus subtended 72˚horizontally, 60˚vertically, consisted of black and white stripes, and moved at 10-50˚/s. Results: All PSP patients showed slowed voluntary vertical saccades and nystagmus quick phases compared with PD or controls. Small, paired, horizontal saccadic intrusions (SWJ) were more frequent and larger in PSP during fixation. Vertical saccades were transiently faster at the time of SWJ and horizontal saccades in PSP. During vertical OK nystagmus, small quick phases were often combined with horizontal SWJ in all subjects; in PSP the vector was closer to horizontal. Vertical OK slow phase gain was reduced in PSP but, in most PD patients, was similar to normals. The average position of gaze shifted in the direction of vertical OK stimulus in PSP patients with preserved slow phase responses but impaired quick phases. Conclusions: Vertical OK responses in PSP show impaired slow phase responses, and quick phases that are slowed and combined with SWJ to produce an oblique vector. SWJ facilitate vertical saccades and quick phases in PSP, but it is unclear whether this is an adaptive process or a result of the disease. A large OK stimulus is useful to induce responses that can be quantitatively analysed in patients with limited voluntary range of vertical gaze.

Adaptive responses to low oxygen (O 2 ) tension (hypoxia) are mediated by the heterodimeric transcription factor hypoxia inducible factor (HIF). When stabilized by hypoxia, bHLH-PAS a-and b-(HIF-1b or ARNT) HIF complex regulate the expression of multiple genes, including vascular endothelial growth factor (VEGF). To investigate the mechanism(s) through which hypoxia contributes to blood vessel development, we used embryonic stem cell (ESC) differentiation cultures that develop into embryoid bodies (EBs) mimicking early embryonic development. Significantly, low O 2 levels promote vascular development and maturation in wild-type (WT) ESC cultures measured by an increase in the numbers of CD31 1 endothelial cells (ECs) and sprouting angiogenic EBs, but refractory in Arnt 2/2 and Vegf 2/2 ESC cultures. Thus, we propose that hypoxia promotes the production of ECs and contributes to the development and maturation of vessels. Our findings further demonstrate that hypoxia alters the temporal expression of VEGF receptors Flk-1 (VEGFR-2) and the membrane and soluble forms of the antagonistic receptor Flt-1 (VEGFR-1). Moreover, these receptors are distinctly expressed in differentiating Arnt 2/2 and Vegf 2/2 EBs. These results support existing models in which VEGF signaling is tightly regulated during specific biologic events, but also provide important novel evidence that, in response to physiologic hypoxia, HIF mediates a distinct stoichiometric pattern of VEGF receptors throughout EB differentiation analogous to the formation of vascular networks during embryogenesis. STEM CELLS 2010;28:799-809 Disclosure of potential conflicts of interest is found at the end of this article.