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891.
Simultaneous nitrification and denitrification using a mixed methanotrophic culture was investigated. When both NO3
–-N (108 mg l–1) and NH3-N (59 mg l–1) were added into batch reactors, nitrate removal was complete within 10 h at the rate of 47 mg NO3
–-N g VSS–1 day–1 when dissolved oxygen (DO) concentration was maintained at 2 mg DO l–1. Ammonia removal started simultaneously with nitrate removal at a slower rate of 14 NH3-N g VSS–1 day–1. No significant accumulation of nitrite or nitrate during ammonia utilization suggested the occurrence of simultaneous nitrification and denitrification. 相似文献
892.
Jungdon Bae Hyunsoo Moon Kyeong-Keun Oh Chang-Ho Kim Dae Sil Lee Seung-Wook Kim Suk-In Hong 《Biotechnology letters》2001,23(16):1315-1319
A novel bioreactor with an internal adsorbent was developed for the simultaneous fermentation and recovery of prodigiosin-like pigment produced from Serratia sp. KH-95 as a model product in one bioreactor. The pigment concentration recovered in the internal adsorbent was 13.1 g l–1, which was 1.8-fold higher than that obtained in a bioreactor with an external adsorbent. 相似文献
893.
Ting PC Lee JF Anthes JC Shih NY Piwinski JJ 《Bioorganic & medicinal chemistry letters》2001,11(4):491-494
The NK1 and NK2 receptor activity of a series of 5-[(3,5-bis(trifluoromethyl)phenyl)methoxy]-3-(3,4-dichlorophenyl)-4(Z)-(methoxyimino)pentyl-1-piperidines was evaluated. Compounds 11d, 11e, 11f, 12a, and 12k were found to be our most potent inhibitors. 相似文献
894.
895.
Tae-Young Lee Myoung-Dong Kim Kyu-Yong Kim Kyungmoon Park Yeon-Woo Ryu Jin-Ho Seo 《Biotechnology and Bioprocess Engineering》2000,5(1):27-31
Characteristics of ethanol production by a xylose-fermenting yeast,Pichia stipitis Y-7124, were studied. The sugar consumption rate and specific growth rate were higher in the glucose-containing medium than
in the xylose-containing medium. Specific activities of xylose reductase and xylitol dehydrogenase were higher in the medium
with xylose than glucose, suggesting their induction by xylose. Maximum specific growth rate and ethanol yield were achieved
at 30 g xylose/L concentration without formation of by-products such as xylitol and acetic acid whereas a maximum ethanol
concentration was obtained at 130 g/L xylose. Adding a respiratory inhibitor, rotenone, increased a maximum ethanol concentration
by 10% compared with the control experiment. In order to evaluate the pattern of ethanol inhibition on specific growth rate,
a kinetic model based on Luong’s equations was applied. The relationship between ethanol concentration and specific growth
rate was hyperbolic for glucose and parabolic for xylose. A maximum ethanol concentration at which cells did not grow was
33.6 g/L for glucose and 44.7 g/L for xylose. 相似文献
896.
Genetic diversity and population history of the red panda (Ailurus fulgens) as inferred from mitochondrial DNA sequence variations 总被引:9,自引:0,他引:9
The red panda (Ailurus fulgens) is one of the flagship species in worldwide conservation and is of special interest in evolutionary studies due to its taxonomic uniqueness. We sequenced a 236-bp fragment of the mitochondrial D-loop region in a sample of 53 red pandas from two populations in southwestern China. Seventeen polymorphic sites were found, together with a total of 25 haplotypes, indicating a high level of genetic diversity in the red panda. However, no obvious genetic divergence was detected between the Sichuan and Yunnan populations. The consensus phylogenetic tree of the 25 haplotypes was starlike. The pairwise mismatch distribution fitted into a pattern of populations undergoing expansion. Furthermore, Fu's F(S) test of neutrality was significant for the total population (F(S) = -7.573), which also suggests a recent population expansion. Interestingly, the effective population size in the Sichuan population was both larger and more stable than that in the Yunnan population, implying a southward expansion from Sichuan to Yunnan. 相似文献
897.
Synthesis and phosphodiesterase 5 inhibitory activity of novel phenyl ring modified sildenafil analogues. 总被引:2,自引:0,他引:2
D K Kim N Lee J Y Lee D H Ryu J S Kim S H Lee J Y Choi K Chang Y W Kim G J Im W S Choi T K Kim J H Ryu N H Kim K Lee 《Bioorganic & medicinal chemistry》2001,9(6):1609-1616
New sildenafil analogues containing an ether ring fused into the phenyl moiety, 6a--d and 7a--d, were efficiently synthesized from the readily available starting materials, 1a--d and 2, in five steps. Ab initio calculations indicated that introduction of a cyclic ether to the phenyl group might enhance the co-planarity of the molecule. The torsional angles were calculated to be 2--3 degrees for the 5-membered cyclic ether derivatives, 6a, 6c, 7a, and 7c, and 12--16 degrees for the 6-membered ones, 6b, 6d, 7b, and 7d. On the other hand, sildenafil showed the least co-planarity with the torsional angle of 23 degrees compared with the target compounds, 6a--d and 7a--d. In the enzyme assay, however, the in vitro PDE 5 inhibitory activity was found out to be inversely related to the degree of co-planarity. In other words, the least planar sildenafil showed the highest activity, and the most planar 5-membered cyclic ether derivatives were least active by 100--200-fold compared with sildenafil. Our study clearly demonstrated that the open chain 2'-alkoxy group of the phenyl ring, although less effective for inducing the co-planarity, seemed to act as a much better lipophilic requirement than the cyclic alkoxy moiety. 相似文献
898.
Different classes of photoreceptor neurons (R cells) in the Drosophila compound eye connect to specific targets in the optic lobe. Using a behavioral screen, we identified LAR, a receptor tyrosine phosphatase, as being required for R cell target specificity. In LAR mutant mosaic eyes, R1-R6 cells target to the lamina correctly, but fail to choose the correct pattern of target neurons. Although mutant R7 axons initially project to the correct layer of the medulla, they retract into inappropriate layers. Using single cell mosaics, we demonstrate that LAR controls targeting of R1-R6 and R7 in a cell-autonomous fashion. The phenotypes of LAR mutant R cells are strikingly similar to those seen in N-cadherin mutants. 相似文献
899.
Neuronal localization of the TNFalpha converting enzyme (TACE) in brain tissue and its correlation to amyloid plaques 总被引:6,自引:0,他引:6
The tumor necrosis factor (TNF)-alpha converting enzyme (TACE) can cleave the cell-surface ectodomain of the amyloid-beta precursor protein (APP), thus decreasing the generation of amyloid-beta (Abeta) by cultured non-neuronal cells. While the amyloidogenic processing of APP in neurons is linked to the pathogenesis of Alzheimer's disease (AD), the expression of TACE in neurons has not yet been examined. Thus, we assessed TACE expression in a series of neuronal and non-neuronal cell types by Western blots. We found that TACE was present in neurons and was only faintly detectable in lysates of astrocytes, oligodendrocytes, and microglial cells. Immunohistochemical analysis was used to determine the cellular localization of TACE in the human brain, and its expression was detected in distinct neuronal populations, including pyramidal neurons of the cerebral cortex and granular cell layer neurons in the hippocampus. Very low levels of TACE were seen in the cerebellum, with Purkinje cells at the granular-molecular boundary staining faintly. Because TACE was localized predominantly in areas of the brain that are affected by amyloid plaques in AD, we examined its expression in a series of AD brains. We found that AD and control brains showed similar levels of TACE staining, as well as similar patterns of TACE expression. By double labeling for Abeta plaques and TACE, we found that TACE-positive neurons often colocalized with amyloid plaques in AD brains. These observations support a neuronal role for TACE and suggest a mechanism for its involvement in AD pathogenesis as an antagonist of Abeta formation. 相似文献
900.
Park SM Yan BC Park JH Choi JH Yoo KY Lee CH Baek YY Kim YM Kang IJ Won MH 《Cellular and molecular neurobiology》2012,32(3):423-434
Tetanus toxin (TeT), an exotoxin, has been studied to cause tetanus in mammalian brains, and it can block the release of some
neurotransmitters and affect seizure propagation. In the present study, we investigated neuronal damage/death and glial changes
in the mouse hippocampus after systemic administration (intraperitoneal injection) of TeT 10 and 100 ng/kg. In both the 10
and 100 ng/kg TeT-treated groups, no neuronal death occurred in any subregions of the mouse hippocampus until 24 h post-treatment;
however, there were changes in glia in the hippocampus depending on time course and dosage. The morphology of GFAP-immunoreactive
astrocytes and Iba-1-immunoreactive microglia was apparently changed in the 100 ng/kg TeT treated-group compared to the 10 ng/kg
TeT treated-group. In the 100 ng/kg TeT treated-group, they were increased in size and their immunoreactivity was distinctively
increased from 12 h post-treatment. We also found that their protein levels were increased in the hippocampus at 12 h post-treatment
of 100 ng/kg TeT. In conclusion, these results indicate that the systemic administration of 100 ng/kg TeT induced a distinctive
microglia changes in the mouse hippocampus without any neuronal death/damage. 相似文献