Comparative Analysis of Five Different Homologous Feeder Cell Lines in the Ability to Support Rhesus Embryonic Stem Cells

我们以前的研究建立了五株猕猴饲养层细胞系来支持猕猴胚胎干细胞(rESCs)的生长:一岁猴耳皮肤成纤维细胞(MESFs)、两岁猴输卵管成纤维细胞(MOFs)、成年猴卵泡颗粒成纤维样细胞(MFGs)、成年猴卵泡颗粒上皮样细胞(MFGEs),以及MESFs的克隆成纤维细胞(CMESFs).我们发现MESFs、CMESFs、MOFs和MFGs,而不足MFGEs支持猕猴胚胎干细胞(rESCs,rhesus embryonic stem cells)的生长.通过半定量PCR的方法,我们在支持性的饲养层细胞中检测到了一些基因的高表达.在本研究中,我们运用Affymetrix公司的GeneChip Rhesus Macaque Genome Array芯片来研究这五株同源饲养层的表达谱,希望发现哪些细胞因子和信号通路在维持rESCs中起到重要作用.结果表明,除MFGE外,包括GREM2、bFGF,、KITLG,、DKK3、GREM1、AREG、SERPINF1和LTBF1等八个基因的mRNA在支持性的饲养层细胞中高表达.本研究结果提示,很多信号通路在支持rESCs的未分化生长和多潜能性方面可能起到了冗余的作用.

Elevated ability to compete for limited food resources by 'all-fish' growth hormone transgenic common carp Cyprinus carpio

Food consumption, number of movements and feeding hierarchy of juvenile transgenic common carp Cyprinus carpio and their size-matched non-transgenic conspecifics were measured under conditions of limited food supply. Transgenic fish exhibited 73 center dot 3% more movements as well as a higher feeding order, and consumed 1 center dot 86 times as many food pellets as their non-transgenic counterparts. After the 10 day experiment, transgenic C. carpio had still not realized their higher growth potential, which may be partly explained by the higher frequency of movements of transgenics and the 'sneaky' feeding strategy used by the non-transgenics. The results indicate that these transgenic fish possess an elevated ability to compete for limited food resources, which could be advantageous after an escape into the wild. It may be that other factors in the natural environment (i.e. predation risk and food distribution), however, would offset this advantage. Thus, these results need to be assessed with caution.

Molecular identification and expression analysis of natural resistance associated macrophage protein (Nramp) cDNA from Japanese flounder (Paralichthys olivaceus)

Natural resistance associated macrophage protein (Nramp) controls partially innate resistance to intracellular parasites. Its function is to enhance the ability of macrophages to kill pathogens. However, little is known about the structure and function of Nramp in lower vertebrates such as teleosts. We have recently isolated a cDNA encoding Nramp from Japanese flounder (Paratichthys olivaceus). The full-length cDNA of the Nramp is 3066 bp in length, including 224 bp 5' terminal UTR, 1662 bp encoding region and 1180 bp 3' terminal UTR. The 1662-nt open reading frame was found to code for a protein with 554 amino acid residues. Comparison of amino acid sequence indicated that Japanese flounder Nramp consists of 12 transmembrane (TM) domains. A consensus transport motif (CTM) containing 20 residues was observed between transmembrane domains 8 and 9. The deduced amino acid sequence of Japanese flounder had 77.30%, 82.71%, 82.67%, 79.64%, 80.72%, 90.97%, 91.16%, 60.14%, 71.48%, 61.69%, 72.37% identity with that of rainbow trout Nramp alpha and beta, channel catfish Nramp, fathead minnow Nramp, common carp Nramp, striped sea bass Nramp, red sea bream Nramp, mouse Nramp 1 and 2, human Nramp 1 and 2, respectively. RT-PCR indicated that Nramp transcripts were highly abundant in spleen, head kidney, abundant in intestine, liver and gill, and less abundant in heart. The level of Nramp mRNA in embryos gradually increases during embryogenesis from 4 h (8 cell stage) to 80 h (hatched stage) after fertilization. (c) 2005 Elsevier Ltd. All rights reserved.

The algae-lytic ability of bacterium DC10 and the influence of environmental factors on the ability

A lysing-bacterium DC10, isolated from Dianchi Lake of Yunnan Province, was characterized to be Pseudomonas sp. It was able to lyse some algae well, such as Microcystis viridis, Selenastrum capricomutum, and so on. In this study, it was shown that the bacterium lysed the algae by releasing a substance; the best lytic effects were achieved at low temperatures and in the dark. Different concentrations of CaCl2 and NaNO3 influenced the lytic effects; the ability to lyse algae decreased in the following order: pH 4 > pH 9 > pH 7 > pH 5.5. It was significant to develop a special technology with this kind of bacterium for controlling the bloom-forming planktonic microalgae.

ARC/INFOR~接受Surfer图文数据的实现

数据是地理信息系统 (GIS)应用的核心。现实世界的数据具有普遍的多样性 ,关于 GIS接受不同数据的研究已成为当前 GIS研究中的一个难点和热点。本文根据通用 GIS工具软件 ARC/INFO接受外部空间数据的方式和图形分析软件 Surfer的数据格式特征 ,运用特定的处理方法实现了由 Surfer格式数据向 ARC/ INFO矢量格式数据 (Coverage)的转换 ,使 ARC/ INFO接受外部数据格式的范围拓宽 ,数据处理能力增强。

Glass formation ability and mechanical properties of Ti40Cu40Zr10Ni10 alloy

Melt-spun ribbon and bulk samples in cylindrical rod form with diameter ranging from 2 mm to 4 mm of Ti40Cu40Zr10Ni10 alloy were prepared by melt-spinning technique and copper mould casting method, respectively. The microstructure, thermal stability and mechanical properties of the bulk samples were investigated. A completely glassy single phase is formed in the 2 mm rod sample. Increasing the diameter of the rod samples resulted in the formation of CuTi crystalline phase in the 3 mm and 4 mm rod samples.

Near infrared long lasting emission of Yb3+ and its influence on the optical storage ability of Mn2+-activated zinc borosilicate glasses

The near infrared long lasting phosphorescence of Yb3+ is observed in Yb3+ and Mn2+ codoped zinc borosilicate glasses. Compared with the glasses solely activated by Mn2+, when the Yb3+ ion is codoped, the red long lasting phosphorescence of the samples is largely improved in both brightness and persistent time but the photostimulated long lasting phosphorescence is greatly depressed. It is considered that the appearance of the phosphorescence of Yb3+ is due to the alteration of the energy transfer channel; additionally, Yb3+ also changes the trap depth of the glasses with the shallower trap predominating therefrom the red long lasting phosphorescence is improved and the photostimulated long lasting phosphorescence is degraded.

A comparison of electrocatalytic ability of various mediators adsorbed onto paraffin impregnated graphite electrodes for oxidation of reduced nicotinamide coenzymes

Twelve mediators have been modified by adsorption onto the paraffin impregnated graphite electrodes (IGE). The resulting electrodes exhibit electrocatalytic activity of different degrees towards oxidation of 1,4-dihydronicotinamide adenine dinucleotide (NADH). The electrocatalytic ability of the chemically modified electrode (CME) depends mainly on the formal potential and molecular structure of mediator. The formation of the charge transfer complex between NADH and adsorbed mediator has been demonstrated by the experiments using a rotating disk electrode. An electrocatalytic scheme obeying Michaelis-Menten kinetics has been confirmed, and some kinetic parameters were estimated. The solution pH influences markedly the electrocatalytic activity of the modified electrode. Various possible reasons are discussed.

Toughening mechanism of polymer blends: Influence of voiding ability of dispersed-phase particles

The parameters which effect the cavitation strain of polymer blends toughened with a shear yield mechanism have been studied by analysis of the stress acted on the equatorial plane of dispersed-phase particles. As a result, the cavitation strain of polymer blends depends on the Young's modulus and the Poisson's ratio of the dispersed-phase particles and the matrix and also on the break stress of dispersed-phase particles. We tried to provide a criterion for selecting the materials used as dispersed-phase particles which can effectively enhance the toughness of polymer blends. (C) 1996 John Wiley & Sons, Inc.

Molecular cloning, characterization and expression analysis of a putative C-type lectin (Fclectin) gene in Chinese shrimp Fenneropenaeus chinensis

Lectin is regarded as a potential molecule involved in immune recognition and phagocytosis through opsonization in crustacean. Knowledge on lectin at molecular level would help us to understand its regulation mechanism in crustacean immune system. A novel C-type lectin gene (Fclectin) was cloned from hemocytes of Chinese shrimp Fenneropenaeus chinensis by 3' and 5' rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA consists of 1482 bp with an 861 bp open reading frame, encoding 287 amino acids. The deduced amino acid sequence contains a putative signal peptide of 19 amino acids. It also contains two carbohydrate recognition domains/C-type lectin-like domains (CRD1 and CRD2), which share 78% identity with each other. CRD1 and CRD2 showed 34% and 30% identity with that of mannose-binding lectin from Japanese lamprey (Lethenteron japonicum), respectively. Both CRD1 and CRD2 of Fclectin have I I amino acids residues, which are relatively invariant in animals' C-type lectin CRDs. Five residues at Ca2+ binding site I are conserved in Fclectin. The potential Ca2+/carbohydrate-binding (site 2) motif QPD, E, NP (Gln-Pro-Asp, Glu, Asn-Pro) presented in the two CRDs of Fclectin may support its ability to bind galactose-type sugars. It could be deduced that Fclectin is a member of C-type lectin superfamily. Transcripts of Fclectin were found only in hemocytes by Northern blotting and RNA in situ hybridization. The variation of mRNA transcription level in hemocytes during artificial infection with bacteria and white spot syndrome virus (WSSV) was quantitated by capillary electrophoresis after RT-PCR. An exploration of mRNA expression variation after LPS stimulation was carried out in primarily cultured hemocytes in vitro. Expression profiles of Fclectin gene were greatly modified after bacteria, LPS or WSSV challenge. The above-stated data can provide us clues to understand the probable role of C-type lectin in innate immunity of shrimp and would be helpful to shrimp disease control. (c) 2006 Elsevier Ltd. All rights reserved.

Identification and molecular analysis of a novel C-type lectin from Scophthalmus maximus

C-type lectins are calcium-dependent carbohydrate-binding proteins that play Important roles in innate immunity In this study, a C-type lectin homologue (SmLec1) was identified from turbot (Scophthalmus maximus) and analyzed at expression and functional levels. The open reading frame of SmLec1 is 504 bp, with a 5'-untranslated region (UTR) of 101 bp and a 3'-UTR of 164 bp The deduced amino acid sequence of SmLec1 shares 34%-38% overall identities with the C-type lectins of several fish species In silico analysis identified in SmLec1 conserved C-type lectin features, including a carbohydrate-recognition domain, four disulfide bond-forming cysteine residues, and the mannose-type carbohydrate-binding motif In addition, SmLec1 possesses a putative signal peptide sequence and is predicted to be localized in the extracellular. Expression of SmLec1 was highest in liver and responded positively to experimental challenges with fish pathogens Recombinant SmLec1 (rSmLec1) purified from yeast was able to agglutinate the Gram-negative fish pathogen Listonella anguillarum but not the Gram-positive pathogen Streptococcus uncle The agglutinating ability of rSmLec1 was abolished in the presence of mannose and ethylenediaminetetraacetic acid and by elevated temperature (65 degrees C) Further analysis showed that rSmLec1 could stimulate kidney lymphocyte proliferation and enhance the killing of bacterial pathogen by macrophages Taken together, these results suggest that SmLec1 is a unique mannose-binding C-type lectin that possesses apparent immunomodulating property and is likely to be involved in host defense against bacterial infection (C) 2010 Elsevier Ltd. All rights reserved

A bioaugmentation failure caused by phage infection and weak biofilm formation ability

Two biological aerated filters (BAF) were setup for ammonia removal treatment of the circulation water in a marine aquaculture. One of the BAFs was bioaugmented with a heterotrophic nitrifying bacterium, Lutimonas sp. H10, where the ammonia removal was not improved and the massive inoculation was even followed by a nitrification breakdown from day 9 to 18. The nitrification was remained stable in control BAF operated under the same conditions. Fluorescent in situ hybridization (FISH) with rRNA-targeted probes and cultivable method revealed that Lutimonas sp. H10 almost disappeared from the bioaugomented BAF within 3 d, and this was mainly due to the infection of a specific phage as revealed by flask experiment, plaque assay and transmission electron observation. Analyses of 16S rRNA gene libraries showed that bacterial groups from two reactors evolved differently and an overgrowth of protozoa was observed in the bioaugmented BAR Therefore, phage infection and poor biofilm forming ability of the inoculated strain are the main reasons for bioaugmentation failure. In addition, gazing by protozoa of the bacteria might be the reason for the nitrification breakdown in bioaugmented BAF during day 9-18.