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51.
Cláudia Maria Luz Lapa Teixeira Fabiana Vasconcelos Kirsten Pedro Celso Nogueira Teixeira 《Journal of applied phycology》2012,24(3):557-563
Microalgal biofuel alternatives have been hindered by their cost and energy intensive production. In the microalgal harvesting process, the intermediate step of flocculation shows potential in drastically reducing the need for costly centrifugation processes. Moringa oleifera seeds, which have been used for water treatment due to their high flocculation potential, low cost and low toxicity, are presented in this paper as strong candidate for flocculating Chlorella vulgaris, a microalgae with high biodiesel production potential. Early results of our group showed a very high flocculation (around 85% of biomass recovery). The aim of this work was to investigate the influence of Moringa oleifera seed flour concentration, sedimentation time and pH on the flocculation efficiency. Cell suspensions treated with Moringa seed flour (1 g L-1) had their flocculation significantly increased with the rise of pH, reaching 89% of flocculation in 120 min at pH 9.2. Sedimentation time of 120 min and a concentration of 0.6 g L-1 proved to be ample for substantial flocculation efficiency. In spite of the need for more research to ensure the economic viability and sustainability of this process, these results corroborate Moringa oleifera seeds as a strong candidate as a bioflocculant for Chlorella vulgaris cells and indicate optimal pH range of its action. 相似文献
52.
The most telomeric class I region of the MHC in rat and mouse is the M region, which contains about 20 class I genes or gene fragments. The central part carries three class I genes—M4, M5, and M6—which are orthologous between the two species. M4 and M6 are pseudogenes in the mouse but transcribed, intact genes in the rat. To analyze the pseudogene status for the mouse genes in more detail, we have sequenced the respective exons in multiple representative haplotypes. The stop codons are conserved in all mouse strains analyzed, and, consistent with the pseudogene status, all strains show additional insertions and deletions, taking the genes further away from functionality. Thus, M4 and M6 indeed have a split status. They are silent in the mouse but intact in the closely related rodent, the rat.GenBank accession numbers: AF057065 to AF057072 (exon 3 of H2-M4 of reported mouse strains), AF057976 to AF057985 (exon 3 of RT1.M4 of reported rat strains), AF058923 and AF058924 (exon 2 of RT1.M4 of strains PVG and BN), AY286080 to AY286092 (exon 4 of H2-M6 of reported mouse stains), and AY303772 (full-length genomic sequence of RT1.M6-1l) 相似文献
53.
Chiou TT Bonhomme B Jin H Miralles CP Xiao H Fu Z Harvey RJ Harvey K Vicini S De Blas AL 《The Journal of biological chemistry》2011,286(25):22456-22468
Collybistin promotes submembrane clustering of gephyrin and is essential for the postsynaptic localization of gephyrin and γ-aminobutyric acid type A (GABA(A)) receptors at GABAergic synapses in hippocampus and amygdala. Four collybistin isoforms are expressed in brain neurons; CB2 and CB3 differ in the C terminus and occur with and without the Src homology 3 (SH3) domain. We have found that in transfected hippocampal neurons, all collybistin isoforms (CB2(SH3+), CB2(SH3-), CB3(SH3+), and CB3(SH3-)) target to and concentrate at GABAergic postsynapses. Moreover, in non-transfected neurons, collybistin concentrates at GABAergic synapses. Hippocampal neurons co-transfected with CB2(SH3-) and gephyrin developed very large postsynaptic gephyrin and GABA(A) receptor clusters (superclusters). This effect was accompanied by a significant increase in the amplitude of miniature inhibitory postsynaptic currents. Co-transfection with CB2(SH3+) and gephyrin induced the formation of many (supernumerary) non-synaptic clusters. Transfection with gephyrin alone did not affect cluster number or size, but gephyrin potentiated the clustering effect of CB2(SH3-) or CB2(SH3+). Co-transfection with CB2(SH3-) or CB2(SH3+) and gephyrin did not affect the density of presynaptic GABAergic terminals contacting the transfected cells, indicating that collybistin is not synaptogenic. Nevertheless, the synaptic superclusters induced by CB2(SH3-) and gephyrin were accompanied by enlarged presynaptic GABAergic terminals. The enhanced clustering of gephyrin and GABA(A) receptors induced by collybistin isoforms was not accompanied by enhanced clustering of neuroligin 2. Moreover, during the development of GABAergic synapses, the clustering of gephyrin and GABA(A) receptors preceded the clustering of neuroligin 2. We propose a model in which the SH3- isoforms play a major role in the postsynaptic accumulation of GABA(A) receptors and in GABAergic synaptic strength. 相似文献
54.
55.
Kristiansen Kell Ørnstrup Holger Brandt Kirsten 《Plant Cell, Tissue and Organ Culture》1999,56(3):145-153
The objective was to reduce in vitro production costs while retaining or improving plant quality, in particular the suitability
for pot plant production. Plants were grown at photosynthetic photon flux densities (PPFD) of 0–40 μmol m-2 s-1 and sucrose concentrations of 3–7% during the multiplication phase and the effects of sucrose, BA, and NAA during root formation
were investigated. Ex vitro growth were tested in both experiments. A small reduction in the rhizome multiplication rate was
found with increasing PPFD and sucrose concentration. Increasing sucrose concentration reduced the number of aerial shoots.
Aerial shoots were etiolated when cultured in darkness and their number increased with increasing PPFD at 3% sucrose, whereas
PPFD did not affect the number of aerial shoots at 5 or 7% sucrose. During the multiplication phase a synergistic promoting
effect of PPFD and sucrose was observed on root formation. Root formation after transfer to rooting medium was affected by
sucrose and PPFD during the multiplication phase. PPFD did not influence root formation after propagation on 7% sucrose, whereas
on 3 or 5 % sucrose root formation was gradually inhibited when PPFD was decreased below 17 μmol m-2 s-1. The formation of thick roots was promoted by propagation in light, and not influenced by sucrose concentration. Ex vitro
growth was not affected by in vitro conditions, except for 7% sucrose during the multiplication phase that reduced flowering.
Root formation on rooting medium was reduced by BA and promoted both by NAA and high levels of sucrose. The root inhibiting
effect of BA could not completely be overcome by simultaneous application of NAA and high sucrose concentrations. Thick roots
were only produced in the presence of NAA, and not affected by sucrose treatment. Ex vitro flowering was negatively influenced
by the presence of BA during root formation and by high levels of sucrose if BA was absent in the rooting medium. High sucrose
levels and NAA could partially compensate for the negative effect of BA on flowering.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
56.
Frense D 《Applied microbiology and biotechnology》2007,73(6):1233-1240
Taxol is a valuable plant-derived drug showing activity against various cancer types. Worldwide efforts had been made to overcome
the supply problem, because the supply by isolation from the bark of the slow-growing yew trees is limited. Plant cell cultures
as well as chemical and biotechnological semisynthesis are processes, which are intensively investigated for the production
of taxanes paclitaxel (Taxol) and docetaxel (Taxotere) in the last few years. This article provides a comparison of the current
research on taxane biosynthesis and production in yew cell cultures. 相似文献
57.
Rescue of foot-and-mouth disease viruses that are pathogenic for cattle from preserved viral RNA samples 总被引:1,自引:0,他引:1
Background
Foot and mouth disease is an economically important disease of cloven-hoofed animals including cattle, sheep and pigs. It is caused by a picornavirus, foot-and-mouth disease virus (FMDV), which has a positive sense RNA genome which, when introduced into cells, can initiate virus replication.Principal Findings
A system has been developed to rescue infectious FMDV from RNA preparations generated from clinical samples obtained under experimental conditions and then applied to samples collected in the “field”. Clinical samples from suspect cases of foot-and-mouth disease (FMD) were obtained from within Pakistan and Afghanistan. The samples were treated to preserve the RNA and then transported to National Veterinary Institute, Lindholm, Denmark. Following RNA extraction, FMDV RNA was quantified by real-time RT-PCR and samples containing significant levels of FMDV RNA were introduced into susceptible cells using electroporation. Progeny viruses were amplified in primary bovine thyroid cells and characterized using antigen ELISA and also by RT-PCR plus sequencing. FMD viruses of three different serotypes and multiple lineages have been successfully rescued from the RNA samples. Two of the rescued viruses (of serotype O and Asia 1) were inoculated into bull calves under high containment conditions. Acute clinical disease was observed in each case which spread rapidly from the inoculated calves to in-contact animals. Thus the rescued viruses were highly pathogenic. The availability of the rescued viruses enabled serotyping by antigen ELISA and facilitated genome sequencing.Conclusions
The procedure described here should improve the characterization of FMDVs circulating in countries where the disease is endemic and thus enhance disease control globally. 相似文献58.
59.
Cyclooxygenase 2 (COX2) is the inducible isozyme of COX, a key enzyme in arachidonate metabolism and the conversion of arachidonic acid (AA) to prostaglandins (PGs) and other eicosanoids. Previous studies have demonstrated that the COX2 protein is up-regulated in prostate cancer cells after irradiation and that this results in elevated levels of PGE(2). In the present study, we further investigated whether radiation-induced COX2 up-regulation is dependent on the redox status of cells from the prostate cancer cell line PC-3. l-Buthionine sulfoximine (BSO), which inhibits gamma glutamyl cysteine synthetase (gammaGCS), and the antioxidants alpha-lipoic acid and N-acetyl-l-cysteine (NAC) were used to modulate the cellular redox status. BSO decreased the cellular GSH level and increased cellular reactive oxygen species (ROS) in PC-3 cells, whereas alpha-lipoic acid and NAC increased the GSH level and decreased cellular ROS. Both radiation and the oxidant H(2)O(2) had similar effects on COX2 up-regulation and PGE(2) production in PC-3 cells, suggesting that radiation-induced COX2 up-regulation is secondary to the production of ROS. The relative increases in COX2 expression and PGE(2) production induced by radiation and H(2)O(2) were even greater when PC-3 cells were pretreated with BSO. When the cells were pretreated with alpha-lipoic acid or NAC for 24 h, both radiation- and H(2)O(2)-induced COX2 up-regulation and PGE(2) production were markedly inhibited. These results demonstrate that radiation-induced COX2 up-regulation in prostate cancer cells is modulated by the cellular redox status. Radiation-induced increases in ROS levels contribute to the adaptive response of PC-3 cells, resulting in elevated levels of COX2. 相似文献
60.