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151.
Xiao-Hai Feng Fei Chen Hong Xu Bo Wu Jun Yao Han-Jie Ying Ping-Kai Ouyang 《Bioprocess and biosystems engineering》2010,33(9):1077-1085
Propionic acid was produced in a multi-point fibrous-bed (MFB) bioreactor by Propionibacterium freudenreichii CCTCC M207015. The MFB bioreactor, comprising spiral cotton fiber packed in a modified 7.5-l bioreactor, was effective for
cell-immobilized propionic acid production compared with conventional free cell fermentation. Batch fermentations at various
glucose concentrations were investigated in the MFB bioreactor. Based on analysis of the time course of production, a fed-batch
strategy was applied for propionic acid production. The maximum propionic acid concentration was 67.05 g l−1 after 496 h of fermentation, and the proportion of propionic acid to total organic acids was approximately 78.28% (w/w).
The MFB bioreactor exhibited excellent production stability during batch fermentation and the propionic acid productivity
remained high after 78 days of fermentation. 相似文献
152.
153.
The objective was to investigate, using a mouse model, the effects of caffeine on the number of ovulated oocytes, the rate of oocyte maturation, the susceptibility of oocytes to activating stimuli, spindle morphology, and distribution of cortical granules (CGs). Mice were given caffeine (150 mg/kg body weight ip) at various times relative to hCG (-2, 0, and +2h); in an in vitro study, 1, 5 or 10 mM caffeine was added to the maturation culture. Caffeine had no effect on the quality of oocytes in vivo maturation, but caffeine was detrimental to the quality of oocytes matured in vitro. Further studies are needed to determine caffeine concentration in follicles relative to that in culture medium. 相似文献
154.
Bruey JM Bruey-Sedano N Luciano F Zhai D Balpai R Xu C Kress CL Bailly-Maitre B Li X Osterman A Matsuzawa S Terskikh AV Faustin B Reed JC 《Cell》2007,129(1):45-56
Caspases are intracellular proteases that cleave substrates involved in apoptosis or inflammation. In C. elegans, a paradigm for caspase regulation exists in which caspase CED-3 is activated by nucleotide-binding protein CED-4, which is suppressed by Bcl-2-family protein CED-9. We have identified a mammalian analog of this caspase-regulatory system in the NLR-family protein NALP1, a nucleotide-dependent activator of cytokine-processing protease caspase-1, which responds to bacterial ligand muramyl-dipeptide (MDP). Antiapoptotic proteins Bcl-2 and Bcl-X(L) bind and suppress NALP1, reducing caspase-1 activation and interleukin-1beta (IL-1beta) production. When exposed to MDP, Bcl-2-deficient macrophages exhibit more caspase-1 processing and IL-1beta production, whereas Bcl-2-overexpressing macrophages demonstrate less caspase-1 processing and IL-1beta production. The findings reveal an interaction of host defense and apoptosis machinery. 相似文献
155.
Wang B Feng WY Wang M Shi JW Zhang F Ouyang H Zhao YL Chai ZF Huang YY Xie YN Wang HF Wang J 《Biological trace element research》2007,118(3):233-243
It has been demonstrated that inhaled fine (d < 2.5 μm) and ultrafine (d < 100 nm) particles produce more severe toxicity than coarse particles. Some recent data support the concept that the central
nervous system (CNS) may be a target for the inhaled fine particulates. This work describes initial observation of the transport
of intranasally instilled fine ferric oxide (Fe2O3) particles in animal brain. The iron micro-distribution and chemical state in the mice olfactory bulb and brain stem on day
14 after intranasal instillation of fine Fe2O3 particle (280 ± 80 nm) suspension at a single dose of 40 mg/kg body weight were analyzed by synchrotron radiation x-ray fluorescence
and x-ray absorption near-edge structure (XANES). The micro-distribution map of iron in the olfactory bulb and brain stem
shows an obvious increase of Fe contents in the olfactory nerve and the trigeminus of brain stem, suggesting that Fe2O3 particles were possibly transported via uptake by sensory nerve endings of the olfactory nerve and trigeminus. The XANES
results indicate that the ratios of Fe (III)/Fe (II) were increased in the olfactory bulb and brain stem. The further histopathological
observation showed that the neuron fatty degeneration occurred in the CA3 area of hippocampus. Such results imply an adverse
impact of inhalation of fine Fe2O3 particles on CNS. 相似文献
156.
We used a newly synthesized allotetraploid between C. sativus (2n = 2x = 14, n gametic chromosome number, x haploid chromosome number) and C. hystrix (2n = 2x = 24) to study the genomic events in its early generations. Results from cytological characterization of the F1 and the allotetraploid progenies showed that the rate of bivalents in meiotic metaphase I of the F1 was greatly improved by chromosome doubling, and further improved during the selfing process of allopolyploid resulting into
relatively diploid-like meiosis. Extensive genomic changes were detected by amplified fragment length polymorphism analysis.
The changes mainly involved loss of parental restriction fragments and gaining of novel fragments. The total detectable changes
were from 11.1 to 32.1%, and the frequency of losing parental fragments was much higher than that of gaining novel fragments.
Some of the changes were initiated as early as in the F1 hybrid, whereas others occurred after chromosome doubling (polyploid formation). No significant differences were detected
in the reciprocal F1 hybrids and S0 generations. But the data showed that the frequency of sequence losing in C. sativus was about two times higher than in the C. hystrix. Our results demonstrated that the sequence elimination was the major event of genomic changes, and it might provide the
physical basis for the diploid-like meiotic behavior in the diploidization of the newly formed allopolyploids. Moreover, the
results suggest that the sequence elimination was not caused by cytoplasmic factors, and might relate to genomic recombination
and to the numbers of parental chromosome. 相似文献
157.
158.
Huang JC Lei ZL Shi LH Miao YL Yang JW Ouyang YC Sun QY Chen DY 《Biochemical and biophysical research communications》2007,354(1):77-83
Histone modifications are thought to play important roles in various cellular functions. In this article, the distribution patterns of acetylation on histone H4, methylation on histone H3 lysine 9, and phosphorylation on histone H3 serine 10 were examined in in vivo and in vitro fertilization (IVF) preimplantation mouse embryos by using indirect immunofluorescence and scanning confocal microscopy. We desired to know whether the IVF, which has been widely used as a routine assisted reproductive technology in animal and human, was safe at the epigenetic level. As results, we found that there was no difference in these histone modification patterns in in vivo and IVF mouse embryos from zygote to blastocyst stage. Moreover, these histone modifications had different distributions at all examined stages, but they were consistent with the mouse embryo developmental stages. 相似文献
159.
Zhu ZY Jiang MX Yan LY Huang JC Lei ZL Jiang Y Ouyang YC Zhang HX Sun QY Chen DY 《Molecular reproduction and development》2007,74(5):655-663
In this study, somatic cell nuclear transfer (SCNT) and intracytoplasmic sperm injection (ICSI) are used as models of agamogony and syngamy, respectively. In order to elucidate the reasons of low efficiency of somatic cell cloning, cytoskeletal and nuclear organization in cloned mouse embryos was monitored before and during the first cell cycle, and compared with the pattern of ICSI zygote. A metaphase-like spindle with alignment of condensed donor chromosomes was assembled within 3 hr after NT, followed by formation of pronuclear-like structures at 3-6 hr after activation, indicating that somatic nuclear remodeling depends on microtubular network organization. The percentage of two (pseudo-) pronuclei in cloned embryos derived from delayed activation was greater than that in immediate activation group (68.5% vs. 30.8%, P<0.01), but similar to that of ICSI group (68.5% vs. 65.5%, P>0.05). The 2-cell rate in NT embryos was significantly lower than that in zygotes produced by ICSI (64.8% vs. 82.5%, P<0.01). Further studies testified that the cloned embryos reached the metaphase of the first mitosis 10 hr after activation, whereas this occurred at 18 hr in the ICSI zygotes. Comparision of the pattern of microfilament assembly in early NT embryos with that in syngamic zygotes suggested that abnormal microfilamental pattern in cloned embryos may threaten subsequent embryonic development. In conclusion, agamogony, in contrast to syngamy, displays some unique features in respect of cytoskeletal organization, the most remarkable of which is that the first cell cycle is initiated ahead distinctly, which probably leads to incomplete organization of the first mitotic spindle, and contributes to low efficiency of cloning. 相似文献
160.
Nan CL Ouyang YC Zhao ZJ Jiang Y Lei ZL Huang JC Song XF Sun QY Chen DY 《Molecular reproduction and development》2007,74(9):1072-1080
This study attempted to investigate the time course of meiotic progression after transferring primary spermatocyte (PS) into ooplasm at different maturing stages. In present experiments, PSs were introduced into maturing ooplasts or oocytes by electrofusion. Higher fusion rate was obtained by phytohemagglutinin (PHA) agglutination than by perivitelline space (PVS) insertion. When the ooplasms prepared at 0, 2, 5, and 8.5 hr of in vitro maturation (IVM) were used as recipients and PSs were used as donors, the reconstructed cells extruded the first polar body (PB1) approximately 8.5, 7, 5.5, and 3 hr after electrofusion, respectively. Especially, when ooplasm cultured for 8.5 hr in vitro after GV removal was fused with PS, the PB1 was emitted 7-11 hr after electrofusion. Additionally, the PB1 extrusions of GV and pro-MI oocytes fertilized with PSs were 2.5 hr earlier than control oocytes. The results suggest that (1) PSs undergo the first meiosis in different time courses when introduced into ooplasm at different maturing stages; (2) GV material plays an important role in determining the timing of PB1 extrusion; and (3) first meiotic division of GV and pro-MI oocytes can be accelerated by introducing PS. 相似文献