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961.
Fan H Tansi FL Weihofen WA Böttcher C Hu J Martinez J Saenger W Reutter W 《European journal of cell biology》2012,91(4):265-273
962.
Huang C Jin H Song B Zhu X Zhao H Cai J Lu Y Chen B Lin Y 《Applied microbiology and biotechnology》2012,93(2):777-785
Alterporriol L, a new bianthraquinone derivative, was isolated from a marine fungus Alternaria sp. ZJ9-6B. The cytotoxic activity and anticancer mechanisms of alterporriol L towards breast cancer cells lines were detected
using MTT assay, immunofluorescence, and flow cytometry. Simultaneously, the changes in morphological properties of cells
were detected before and after treatment with alterporriol L by atomic force microscope (AFM) at a nanometer scale. MTT assay
showed that alterporriol L could effectively inhibit the growth and proliferation, and there was a dose-dependent manner of
cell death. Moreover, the alterporriol L could induce cancer cell apoptosis or necrosis. Furthermore, the reactive oxygen
species, mitochondrial membrane potential, and cytosolic free calcium level were changed after treatment with alterporriol
L, suggesting that alterporriol L played vital roles in breast cancer cells through destroying the mitochondrial. And all
these alterations are in accord with changes of morphology detected by AFM, which suggested that the AFM is a useful tool
to detect the morphological changes of the cancer cells. 相似文献
963.
Yuanjing Li Chunjie Tian Hua Tian Jiliang Zhang Xin He Wenxiang Ping Hong Lei 《Applied microbiology and biotechnology》2012,96(6):1479-1487
Nowadays, bacterial cellulose has played more and more important role as new biological material for food industry and medical and industrial products based on its unique properties. However, it is still a difficult task to improve the production of bacterial cellulose, especially a large number of byproducts are produced in the metabolic biosynthesis processes. To improve bacterial cellulose production, ethanol and sodium citrate are added into the medium during the fermentation, and the activities of key enzymes and concentration of extracellular metabolites are measured to assess the changes of the metabolic flux of the hexose monophosphate pathway (HMP), the Embden–Meyerhof–Parnas pathway (EMP), and the tricarboxylic acid cycle (TCA). Our results indicate that ethanol functions as energy source for ATP generation at the early stage of the fermentation in the HMP pathway and the supplementation of ethanol significantly reduces glycerol generation (a major byproduct). While in the EMP pathway, sodium citrate plays a key role, and its supplementation results in the byproducts (mainly acetic acid and pyruvic acid) entering the gluconeogenesis pathway for cellulose synthesis. Furthermore, by adding ethanol and sodium citrate, the main byproduct citric acid in the TCA cycle is also reduced significantly. It is concluded that bacterial cellulose production can be improved by increasing energy metabolism and reducing the formation of metabolic byproducts through the metabolic regulations of the bypasses. 相似文献
964.
Shi Q Luo S Jin H Cai J Jia H Feng L Lu X 《Applied microbiology and biotechnology》2012,94(2):479-486
We successfully differentiated human adipose tissue-derived mesenchymal stem cells (haMSCs) into insulin-producing cells (IPCs)
in vitro and did not use any insulin which might be absorbed by cells during in vitro culture. Expression of insulin gene
was massively increased by 28,000-fold at day 12 compared with haMSCs (P < 0.05). IPCs could secrete insulin after glucose was stimulated. The higher the concentration of glucose, the more production
of insulin was noted. We reported AFM images of IPCs for the first time. AFM images showed that the sizes of cells were similar
to each other, and all IPC surface had a porous structure in the cytoplasm area. In sugar-free group, the size of holes was
similar (diameter, 1,086.98 ± 156.70 nm; depth, 185.22 ± 52.14 nm). In higher sugar-stimulated group, there were more holes
with bigger diameter and smaller depth. (diameter, 3,183.65 ± 2,229.18 nm; depth 109.42 ± 56.26 nm, P < 0.05). We found that the hole diameter and depth could change with the concentration of glucose in media. Concurrently,
laser scanning confocal microscopy images indicated that cortical actin network beneath plasma membrane in IPCs was dense
and continuous. After glucose stimulation, we found the actin web depolymerized and became discontinuous in IPCs. We speculated
that diameter augmentation of holes located in the cytoplasm area in IPCs was one manifestation of excytosis increase. 相似文献
965.
966.
967.
968.
Hu J Sun L Shen F Chen Y Hua Y Liu Y Zhang M Hu Y Wang Q Xu W Sun F Ji J Murray JM Carr AM Kong D 《Cell》2012,149(6):1221-1232
When replication forks stall at damaged bases or upon nucleotide depletion, the intra-S phase checkpoint ensures they are stabilized and can restart. In intra-S checkpoint-deficient budding yeast, stalling forks collapse, and ~10% form pathogenic chicken foot structures, contributing to incomplete replication and cell death (Lopes et al., 2001; Sogo et al., 2002; Tercero and Diffley, 2001). Using fission yeast, we report that the Cds1(Chk2) effector kinase targets Dna2 on S220 to regulate, both in vivo and in vitro, Dna2 association with stalled replication forks in chromatin. We demonstrate that Dna2-S220 phosphorylation and the nuclease activity of Dna2 are required to prevent fork reversal. Consistent with this, Dna2 can efficiently cleave obligate precursors of fork regression-regressed leading or lagging strands-on model replication forks. We propose that Dna2 cleavage of regressed nascent strands prevents fork reversal and thus stabilizes stalled forks to maintain genome stability during replication stress. 相似文献
969.
Lagerstroemia menglaensis C. H. Gu, M. C. Ji & D. D. Ma, a new species of Lythraceae from Xishuangbanna, Yunnan, China is described and illustrated. The morphological characteristics of the new species and two morphologically similar species (L. guilinensis and L. venusta) are compared, and a key to distinguish between them is provided. 相似文献
970.
A new species of Gesneriaceae, Primulina xiziae Fang Wen, Yue Wang & G. J. Hua, from Zhejiang Province, China, is identified, illustrated and described. It resembles the widespread P. eburnea, and the stenochoric P. pseudoeburnea, but differs by the leaf blades being ovate‐elliptic or ovate, chartaceous with ciliate margins, 8.5–13.8 mm long, slender peduncle, ovate, ca 1.2 × 1.0 cm large bracts that are generally withered but persistent before full‐blooming stage, slender tubular‐infundibuliform, ca 25.0 × 7.5 mm corolla tube, limb lobes with acute apices, 3 staminodes, and by forming a dormancy bud in winter. 相似文献