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31.
Engineering photosynthetic light capture: impacts on improved solar energy to biomass conversion 总被引:1,自引:0,他引:1
Mussgnug JH Thomas-Hall S Rupprecht J Foo A Klassen V McDowall A Schenk PM Kruse O Hankamer B 《Plant biotechnology journal》2007,5(6):802-814
The main function of the photosynthetic process is to capture solar energy and to store it in the form of chemical 'fuels'. Increasingly, the photosynthetic machinery is being used for the production of biofuels such as bio-ethanol, biodiesel and bio-H2 . Fuel production efficiency is directly dependent on the solar photon capture and conversion efficiency of the system. Green algae (e.g. Chlamydomonas reinhardtii ) have evolved genetic strategies to assemble large light-harvesting antenna complexes (LHC) to maximize light capture under low-light conditions, with the downside that under high solar irradiance, most of the absorbed photons are wasted as fluorescence and heat to protect against photodamage. This limits the production process efficiency of mass culture. We applied RNAi technology to down-regulate the entire LHC gene family simultaneously to reduce energy losses by fluorescence and heat. The mutant Stm3LR3 had significantly reduced levels of LHCI and LHCII mRNAs and proteins while chlorophyll and pigment synthesis was functional. The grana were markedly less tightly stacked, consistent with the role of LHCII. Stm3LR3 also exhibited reduced levels of fluorescence, a higher photosynthetic quantum yield and a reduced sensitivity to photoinhibition, resulting in an increased efficiency of cell cultivation under elevated light conditions. Collectively, these properties offer three advantages in terms of algal bioreactor efficiency under natural high-light levels: (i) reduced fluorescence and LHC-dependent heat losses and thus increased photosynthetic efficiencies under high-light conditions; (ii) improved light penetration properties; and (iii) potentially reduced risk of oxidative photodamage of PSII. 相似文献
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Foo LC Allen NJ Bushong EA Ventura PB Chung WS Zhou L Cahoy JD Daneman R Zong H Ellisman MH Barres BA 《Neuron》2011,71(5):799-811
The inability to purify and culture astrocytes has long?hindered studies of their function. Whereas astrocyte progenitor cells can be cultured from neonatal brain, culture of mature astrocytes from postnatal brain has not been possible. Here, we report a new method to prospectively purify astrocytes by immunopanning. These astrocytes undergo apoptosis in culture, but vascular cells and HBEGF promote their survival in serum-free culture. We found that some developing astrocytes normally undergo apoptosis in?vivo and that the vast majority of astrocytes contact blood vessels, suggesting that?astrocytes are matched to blood vessels by competing for vascular-derived trophic factors such as HBEGF. Compared to traditional astrocyte cultures, the gene profiles of the cultured purified postnatal astrocytes much more closely resemble those of in?vivo astrocytes. Although these astrocytes strongly promote synapse formation and function, they do not secrete glutamate in response to stimulation. 相似文献
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Duan M Kazmierski WM Chong PY Deanda F Edelstein M Ferris R Peckham J Wheelan P Xiong Z Zhang H Nishizawa R Takaoka Y 《Bioorganic & medicinal chemistry letters》2011,21(21):6470-6475
A novel series of pyridyl carboxamide-based CCR5 inhibitors was designed, synthesized, and demonstrated to be highly potent against HIV-1 infection in both HOS and PBL assays. Attempts to evaluate this series of compounds in a rat PK model revealed its instability in rat plasma. A hypothesis for this liability was proposed, and strategies to overcome this issue were pursued, leading to discovery of highly potent 40 and 41, which featured dramatically improved rat PK profiles. 相似文献
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Tallant MD Duan M Freeman GA Ferris RG Edelstein MP Kazmierski WM Wheelan PJ 《Bioorganic & medicinal chemistry letters》2011,21(5):1394-1398
We describe the synthesis and potency of a novel series of N-substituted 2-phenyl- and 2-methyl-2-phenyl-1,4-diaminobutane- based CCR5 antagonists. Compounds 7a and 12f were found to be potent in anti-HIV assays and bioavailable in the low-dose rat PK model. 相似文献
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Natarajan JV Chattopadhyay S Ang M Darwitan A Foo S Zhen M Koo M Wong TT Venkatraman SS 《PloS one》2011,6(9):e24513
Topical medication remains the first line treatment of glaucoma; however, sustained ocular drug delivery via topical administration is difficult to achieve. Most drugs have poor penetration due to the multiple physiological barriers of the eye and are rapidly cleared if applied topically. Currently, daily topical administration for lowering the intra-ocular pressure (IOP), has many limitations, such as poor patient compliance and ocular allergy from repeated drug administration. Poor compliance leads to suboptimal control of IOP and disease progression with eventual blindness. The delivery of drugs in a sustained manner could provide the patient with a more attractive alternative by providing optimal therapeutic dosing, with minimal local toxicity and inconvenience. To investigate this, we incorporated latanoprost into LUVs (large unilamellar vesicles) derived from the liposome of DPPC (di-palmitoyl-phosphatidyl-choline) by the film hydration technique. Relatively high amounts of drug could be incorporated into this vesicle, and the drug resides predominantly in the bilayer. Vesicle stability monitored by size measurement and DSC (differential scanning calorimetry) analysis showed that formulations with a drug/lipid mole ratio of about 10% have good physical stability during storage and release. This formulation demonstrated sustained release of latanoprost in vitro, and then tested for efficacy in 23 rabbits. Subconjunctival injection and topical eye drop administration of the latanoprost/liposomal formulation were compared with conventional daily administration of latanoprost eye drops. The IOP lowering effect with a single subconjunctival injection was shown to be sustained for up to 50 days, and the extent of IOP lowering was comparable to daily eye drop administration. Toxicity and localized inflammation were not observed in any treatment groups. We believe that this is the first demonstration, in vivo, of sustained delivery to the anterior segment of the eye that is safe and efficacious for 50 days. 相似文献
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Yuan Q Ouyang S Wang A Zhu W Maiti R Lin H Hamilton J Haas B Sultana R Cheung F Wortman J Buell CR 《Plant physiology》2005,139(1):18-26
We have developed a rice (Oryza sativa) genome annotation database (Osa1) that provides structural and functional annotation for this emerging model species. Using the sequence of O. sativa subsp. japonica cv Nipponbare from the International Rice Genome Sequencing Project, pseudomolecules, or virtual contigs, of the 12 rice chromosomes were constructed. Our most recent release, version 3, represents our third build of the pseudomolecules and is composed of 98% finished sequence. Genes were identified using a series of computational methods developed for Arabidopsis (Arabidopsis thaliana) that were modified for use with the rice genome. In release 3 of our annotation, we identified 57,915 genes, of which 14,196 are related to transposable elements. Of these 43,719 non-transposable element-related genes, 18,545 (42.4%) were annotated with a putative function, 5,777 (13.2%) were annotated as encoding an expressed protein with no known function, and the remaining 19,397 (44.4%) were annotated as encoding a hypothetical protein. Multiple splice forms (5,873) were detected for 2,538 genes, resulting in a total of 61,250 gene models in the rice genome. We incorporated experimental evidence into 18,252 gene models to improve the quality of the structural annotation. A series of functional data types has been annotated for the rice genome that includes alignment with genetic markers, assignment of gene ontologies, identification of flanking sequence tags, alignment with homologs from related species, and syntenic mapping with other cereal species. All structural and functional annotation data are available through interactive search and display windows as well as through download of flat files. To integrate the data with other genome projects, the annotation data are available through a Distributed Annotation System and a Genome Browser. All data can be obtained through the project Web pages at http://rice.tigr.org. 相似文献