Annotated lipids in <i>C</i>. <i>reinhardtii</i> under nitrogen and sulfur stress conditions.

<p>^a: represented these lipids only can be annotated using Lipidblast;</p><p>^b: represented these lipids only can be annotated using MS2Analyzer;</p><p>^c: represented these lipids can be annotated by both databases.</p><p>The reverse dot product represents the level of confidence from in silico-MS/MS library search. Compound annotations without reverse dot product were annotated using MS2Analyzer.</p

Univariate box-whisker plots of triacylglycerol and betaine lipid species in <i>C</i>. <i>reinhardtii</i> in temporal response to nitrogen deprivation.

<p>Arithmetic mean values with ±S.E. as box and ±1.96 S.E. as whiskers.</p

Common lipid species reported for <i>Chlamydomonas reinhardtii</i> cells.

<p>Labels R1, R2 and R3 represent different fatty acid acyl residues.</p

Annotation of complex lipids in algae by matching nanoelectrospray-linear ion trap MS/MS low resolution fragment spectra against the UC Davis LipidBlast library.

<p>Mass accuracy is <0.4 Da. Upper left panel: Annotation of the MS/MS spectrum from precursor m/z 750.9 Da as betaine lipid DGTS 35:2 (16:0/19:2); Upper right panel: Annotation of betaine lipid DGTS 36:2 (18:0/18:2); Lower left panel: Annotation of triacylglycerol TAG 56:0 (16:0/20:0/20:0); Lower right panel: Annotation of triacylglycerol TAG 61:0 (20:0/20:0/21:0).</p

Lipidomic Analysis of <i>Chlamydomonas reinhardtii</i> under Nitrogen and Sulfur Deprivation

<div><p><i>Chlamydomonas reinhardtii</i> accumulates lipids under complete nutrient starvation conditions while overall growth in biomass stops. In order to better understand biochemical changes under nutrient deprivation that maintain production of algal biomass, we used a lipidomic assay for analyzing the temporal regulation of the composition of complex lipids in <i>C</i>. <i>reinhardtii</i> in response to nitrogen and sulfur deprivation. Using a chip-based nanoelectrospray direct infusion into an ion trap mass spectrometer, we measured a diversity of lipid species reported for <i>C</i>. <i>reinhardtii</i>, including PG phosphatidylglycerols, PI Phosphatidylinositols, MGDG monogalactosyldiacylglycerols, DGDG digalactosyldiacylglycerols, SQDG sulfoquinovosyldiacylglycerols, DGTS homoserine ether lipids and TAG triacylglycerols. Individual lipid species were annotated by matching mass precursors and MS/MS fragmentations to the in-house LipidBlast mass spectral database and MS2Analyzer. Multivariate statistics showed a clear impact on overall lipidomic phenotypes on both the temporal and the nutrition stress level. Homoserine-lipids were found up-regulated at late growth time points and higher cell density, while triacyclglycerols showed opposite regulation of unsaturated and saturated fatty acyl chains under nutritional deprivation.</p></div

Univariate box-whisker plots of triacylglycerol, betaine and sulfoquinovosyl lipid species in <i>C</i>. <i>reinhardtii</i> in temporal response to sulfur deprivation.

<p>Arithmetic mean values with ±S.E. as box and ±1.96 S.E. as whiskers.</p

Growth curves of <i>C</i>. <i>reinhardtii</i> after transfer to nitrogen-deprived (left panel) or sulfur-deprived media (right panel).

<p>The values are averages ±SE (standard deviation) for six replicate culture flasks.</p

Protein Microspheres with Unique Green and Red Autofluorescence for Noninvasively Tracking and Modeling Their in Vivo Biodegradation

Bovine serum albumin (BSA) microspheres were prepared through a facile and low-cost route including a high-speed dispersion of BSA in cross-linking solution followed by spray drying. Interestingly the as-prepared BSA microspheres possess unique blue-green, green, green-yellow, and red fluorescence when excited by specific wavelengths of laser or LED light. The studies of UV–visible reflectance spectra and fluorescence emission spectra indicated that four classes of fluorescent compounds are presumably formed during the fabrication processes. The formation and the potential contributors for the unique green and red autofluorescence were also discussed and proposed though the exact structures of the fluorophores formed remain elusive due to the complexity of the protein system. The effect of spray-drying conditions on the morphology of spray-dried samples was investigated and optimized. FTIR was further employed to characterize the formation of the functional groups in the as-prepared autofluorescent microspheres. Good in vitro and in vivo biocompatibility was demonstrated by the cytotoxicity test on the A549 cancer cells and tissue histological analysis, respectively. The autofluorescent BSA microspheres themselves were then applied as a novel tracer for convenient tracking/modeling of the biodegradation of autofluorescent BSA microspheres injected into mouse model based on noninvasive, time-dependent fluorescence images of the mice, in which experimental data are in good agreement with the proposed mathematical model. All these studies indicate that the as-developed protein microspheres exhibiting good biocompatibility, biodegradability, and unique autofluorescence, can significantly broaden biomedical applications of fluorescent protein particles

Long Circulating Self-Assembled Nanoparticles from Cholesterol-Containing Brush-Like Block Copolymers for Improved Drug Delivery to Tumors

Amphiphilic brush-like block copolymers composed of polynorbonene-cholesterol/poly­(ethylene glycol) (P­(NBCh9-<i>b</i>-NBPEG)) self-assembled to form a long circulating nanostructure capable of encapsulating the anticancer drug doxorubicin (DOX) with high drug loading (22.1% w/w). The release of DOX from the DOX-loaded P­(NBCh9-<i>b</i>-NBPEG) nanoparticles (DOX-NPs) was steady at less than 2% per day in PBS. DOX-NPs were effectively internalized by human cervical cancer cells (HeLa) and showed dose-dependent cytotoxicity, whereas blank nanoparticles were noncytotoxic. The DOX-NPs demonstrated a superior <i>in vivo</i> circulation time relative to that of free DOX. Tissue distribution and <i>in vivo</i> imaging studies showed that DOX-NPs preferentially accumulated in tumor tissue with markedly reduced accumulation in the heart and other vital organs. The DOX-NPs greatly improved survival and significantly inhibited tumor growth in tumor-bearing SCID mice compared to that for the untreated and free DOX-treated groups. The results indicated that self-assembled P­(NBCh9-<i>b</i>-NBPEG) may be a useful carrier for improving tumor delivery of hydrophobic anticancer drugs