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991.
Zhen Xing Zhang Qi Xin Zheng Yong Chao Wu Ding Jun Hao 《Biotechnology and Bioprocess Engineering》2010,15(4):545-551
In this study, we evaluated the behavior of neural stem cells (NSCs) using a new peptide hydrogel scaffold named IKVAVmx,
which was made by mixing self-assembling peptide RADA16 and designer peptide RADA16-IKVAV solutions. NSCs derived from rat
cerebral cortex were culture-expanded in neuorobasal medium and seeded on the RADA16 and IKVAVmx hydrogels. Cells could penetrate
the hydrogels and form a 3D cellular network. Compared to pure RADA16 scaffold, we found that IKVAVmx scaffold significantly
promoted cell proliferation and stimulated cell migration into the 3D scaffold. Moreover, Immunocytochemistry and Western
blot analysis indicated that the differentiation ratio of neurons from NSCs in IKVAVmx scaffold was higher than that in pure
RADA16 scaffold. These results suggested that this new hydrogel scaffold provided an ideal substrate for NSCs 3D culture and
suggested its further application for neural tissue engineering. 相似文献
992.
Mao-feng Yue Ren-chao Zhou Ye-lin Huang Guo-rong Xin Su-hua Shi Li Feng 《Journal of Plant Biology》2010,53(2):165-171
High levels of genetic variation enable species to adapt to changing environments and provide plant breeders with the raw
materials necessary for artificial selection. In the present study, six AFLP primer pairs were used to assess the genetic
diversity of Desmodium triflorum (L.) DC. from 12 populations in South China. A high percentage of polymorphic loci (P = 76.16%) and high total gene diversity (H
T = 0.310) were found, indicating that the genetic diversity of D. triflorum is high at the species level. Genetic diversity was also relatively high at the population level (P = 55.85%, H
e = 0.230). The coefficient of gene differentiation among populations (G
ST) was 0.255, indicating that while most genetic diversity resided within populations, there was also considerable differentiation
among populations. AMOVA also indicated 24.29% of the total variation to be partitioned among populations (ΦST = 0.243). UPGMA clustering analysis based on genetic distances showed that the 12 populations could be separated into three
subgroups: an eastern, a western, and a central-southern subgroup. However, a Mantel test revealed no significant correlation
(r = 0.286, p = 0.983) between the geographical distances and genetic distances separating these populations; mountain barriers to gene
flow and human disturbance may have confounded these correlations. The present study has provided some fundamental genetic
data that will be of use in the exploitation of D. triflorum. 相似文献
993.
994.
Using nicking DNA endonuclease (NiDE), we developed a novel technique to clone DNA fragments into plasmids. We created a NiDE cassette consisting of two inverted NiDE substrate sites sandwiching an asymmetric four-base sequence, and NiDE cleavage resulted in 14-base single-stranded termini at both ends of the vector and insert. This method can therefore be used as a ligation-independent cloning strategy to generate recombinant constructs rapidly. In addition, we designed and constructed a simple and specific vector from an Escherichia coli plasmid back-bone to complement this cloning method. By cloning cDNAs into this modified vector, we confirmed the predicted feasibility and applicability of this cloning method. 相似文献
995.
996.
Dietary α-ketoglutarate supplementation ameliorates intestinal injury in lipopolysaccharide-challenged piglets 总被引:2,自引:0,他引:2
Yongqing Hou Lei Wang Binying Ding Yulan Liu Huiling Zhu Jian Liu Yongtang Li Xin Wu Yulong Yin Guoyao Wu 《Amino acids》2010,39(2):555-564
Neonates are at increased risk for inflammatory bowel disease, but effective prevention and treatments are currently limited.
This study was conducted with the lipopolysaccharide (LPS)-challenged piglet model to determine the effects of dietary supplementation
with α-ketoglutarate (AKG) on the intestinal morphology and function. Eighteen 24-day-old pigs (weaned at 21 days of age)
were assigned randomly to control, LPS, and LPS + AKG groups. The piglets in the control and LPS groups were fed a corn-
and soybean meal-based diet, whereas the LPS + AKG group was fed the basal diet supplemented with 1% AKG. On days 10, 12,
14, and 16, piglets in the LPS and LPS + AKG groups received intraperitoneal administration of LPS (80 μg/kg BW), whereas
piglets in the control group received the same volume of saline. On day 16, d-xylose was orally administrated to all pigs at the dose of 0.1 g/kg BW, 2 h after LPS or saline injection, and blood samples
were collected 3 h thereafter. Twenty-four hours post-administration of LPS or saline, pigs were killed to obtain intestinal
mucosae for analysis. Compared with the control group, LPS challenge reduced (P < 0.05) protein levels, the ratio of villus height to crypt depth, and the ratio of phosphorylated mTOR to total mTOR in
duodenal, jejunal, and ileal mucosa. These adverse effects of LPS were attenuated (P < 0.05) by AKG supplementation. Moreover, AKG prevented the LPS-induced increase in intestinal HSP70 expression. Collectively,
these novel results indicate that dietary supplementation with 1% AKG activates the mTOR signaling, alleviates the mucosal
damage, and improves the absorptive function of the small intestine in LPS-challenged piglets. The findings not only help
understand the mode of AKGs actions in the neonatal gut but also have important implications for infant nutrition under inflammatory
conditions. 相似文献
997.
Xin Wu Zheng Ruan Yunling Gao Yulong Yin Xihong Zhou Lei Wang Meimei Geng Yongqing Hou Guoyao Wu 《Amino acids》2010,39(3):831-839
This study determined effects of dietary supplementation with l-arginine (Arg) or N-carbamylglutamate (NCG) on intestinal health and growth in early-weaned pigs. Eighty-four Landrace × Yorkshire pigs (average
body weight of 5.56 ± 0.07 kg; weaned at 21 days of age) were fed for 7 days one of the three isonitrogenous diets: (1) a
corn- and soybean meal-based diet (CSM), (2) CSM + 0.08% NCG (0.08%), and (3) CSM + 0.6% Arg. There were four pens of pigs
per diet (7 pigs/pen). At the end of a 7-day feeding period, six piglets were randomly selected from each treatment for tissue
collections. Compared with the control group, Arg or NCG supplementation increased (P < 0.05): (1) Arg concentrations in plasma, (2) small-intestinal growth, (3) villus height in duodenum, jejunum and ileum,
(4) crypt depth in jejunum and ileum, (5) goblet cell counts in intestinal mucosae, and (6) whole-body weight gain in pigs.
Real-time polymerase chain reaction and western blotting analyses revealed that both mRNA and protein levels for heat shock
protein-70 (HSP70) were higher (P < 0.05) in the intestinal mucosae of Arg- or NCG-supplemented pigs than in the control group. Furthermore, the incidence
of diarrhea in the NCG group was 18% lower (P < 0.01) than that in the control group. Collectively, these results indicate that dietary supplementation with 0.6% Arg or
0.08% NCG enhances intestinal HSP70 gene expression, intestinal growth and integrity, and the availability of dietary nutrients
for whole-body weight gain in postweaning pigs fed a CSM-based diet. Thus, Arg or NCG is a functional ingredient in the weaning
diet to improve nutrition, health, and growth performance of these neonates. 相似文献
998.
Germ cells and somatic cells have the identical genome. However, unlike the mortal fate of somatic cells, germ cells have the unique ability to differentiate into gametes that retain totipotency and produce an entire organism upon fertilization. The processes by which germ cells differentiate into gametes, and those by which gametes become embryos, involve dramatic cellular differentiation accompanied by drastic changes in gene expression, which are tightly regulated by genetic circuitries as well as epigenetic mechanisms. Epigenetic regulation refers to heritable changes in gene expression that are not due to changes in primary DNA sequence. The past decade has witnessed an ever-increasing understanding of epigenetic regulation in many different cell types/tissues during embryonic development and adult homeostasis. In this review, we focus on recent discoveries of epigenetic regulation of germ cell differentiation in various metazoan model organisms, including worms, flies, and mammals. 相似文献
999.
1000.
Li Ben Eric Dale Jones Enkun Zhou Chen Li Dean Cameron Baylis Shanghai Yu Miao Wang Xing He Jonathan Alan Victor Coates David Ian Rhodes Gang Pei John Joseph Deadman Xin Xie Dawei Ma 《Bioorganic & medicinal chemistry letters》2010,20(14):4012-4014
A novel series of CCR5 antagonists has been identified, utilizing the lead, nifeviroc, which were further modified based on bioisosteric principles. Lead optimization was pursued by balancing potential toxicity and potency. Potent analogues with low toxic properties were successfully developed by formation of urea and amide bonds at the nitrogen at position 4- of the pyrrolidine ring. 相似文献