The expression of AmphiTCTP, a TCTP orthologous gene in amphioxus related to the development of notochord and somites

The translationally controlled tumor protein (TCTP) is highly conserved and has been widely found in eukaryotic organisms. Here, we report the phylogenetic analysis and developmental expression of AmphiTCTP, a TCTP homologous gene in cephalochordate amphioxus. Phylogenetic analysis indicates that the putative protein of AmphiTCTP is close to its vertebrate orthologs. The mRNA of AmphiTCTP is found in fertilized eggs, early cleavage embryo and most of the early developmental stages by in situ hybridization and RT-PCR, but its expression is not detectable from late cleavage stage to mid-gastrula. The expression of AmphiTCTP in zygotes and early cleavage stages shows that AmphiTCTP may be a maternal gene. From the early neurula stage onward, AmphiTCTP transcript is localized in the presumptive notochord, presomitic mesoderm, and nascent somites. However, its expression is gradually down-regulated after the notochord and somites have been formed. The expression pattern of AmphiTCTP thus coincides with the differentiation of the notochord and somites, this suggests that AmphiTCTP may not be a housekeeping gene and may play an important role in mesoderm development. (c) 2007 Elsevier Inc. All rights reserved.

Stability Analysis Of The Moving Interface In Piston- And Non-Piston-Like Displacements

From the macroscopic point of view, expressions involving reservoir and operational parameters are established for investigating the stability of moving interface in piston- and non-piston-like displacements. In the case of axi-symmetrical piston-like displacement, the stability is related to the moving interface position and water to oil mobility ratio. The capillary effect on the stability of moving interface depends on whether or not the moving interface is already stable and correlates with the wettability of the reservoir rock. In the case of non-piston-like displacement, the stability of the front is governed by both the relative permeability and the mobility ratio.

Effects of exogenous double-stranded RNA on the basonuclin gene expression in mouse oocytes

In plants and less-advanced animal species, such as C.elegans, introduction of exogenous double-stranded RNA (dsRNA) into cells would trigger degradation of the mRNA with homologous sequence and interfere with the endogenous gene expression. It might represent an ancient anti-virus response which could prevent the mutation in the genome that was caused by virus infection or mobile DNA elements insertion. This phenomenon was named RNA interference, or RNAi. In this study, RNAi was used to investigate the function of basonuclin gene during oogenesis. Microinjection of dsRNA directed towards basonuclin into mouse germinal-vesicle-intact (GV) oocytes brought down the abundance of the cognate mRNA effectively in a time- and concentration-dependent manner. This reduction effect was sequence-specific and showed no negative effect on other non-homologous gene expression in oocytes, which indicated that dsRNA can recognize and cause the degradation of the transcriptional products of endogenous basonuclin gene in a sequence-specific manner. Immunofluorescence results showed that RNAi could reduce the concentration of basonuclin protein to some extent, but the effect was less efficient than the dsRNA targeting towards tPA and cMos which was also expressed in oocytes. This result might be due to the long half life of basonuclin protein in oocytes and the short reaction time which was posed by the limited life span of GV oocytes cultured in vitro. In summary, dsRNA could inhibit the expression of the cognate gene in oocytes at both mRNA and protein levels. The effect was similar to Knock-out technique which was based on homologous recombination. Furthermore, hairpin-style dsRNA targeting basonuclin gene could be produced by transcription from a recombinant plasmid and worked efficiently to deplete the cognate mRNA in oocytes. This finding offered a new way to study the function of basonuclin in the early stage of oogenesis by infection of primordial oocytes with the plasmid expressing hairpin-style basonuclin dsRNA.

Interaction of low-molecular-weight chitosan with mimic membrane studied by electrochemical methods and surface plasmon resonance

Chitosan has shown its potential as a non-viral gene carrier and an adsorption enhancer for subsequent drug delivery to cells. These results showed that chitosan acted as a membrane perturbant. However, there is currently a lack of direct experimental evidence of this membrane perturbance effect, especially for chitosans with low molecular weight (LMW). In this report, the interaction between a lipid (didodecyl dimethylammonium bromide; DDAB) bilayer and chitosan with molecular weight (MW) of 4200 Da was studied with cyclic voltammetry (CV), electrochemical impedance spectroscopy and surface plasmon resonance (SPR). A lipid bilayer was formed by-fusion of oppositely charged lipid vesicles on a mercaptopropionic acid (MPA)-modified gold surface to mimic a cell membrane. The results showed that the LMW chitosan could disrupt the lipid bilayer, and the effect seemed,to be in a concentration-dependent manner.

Non-monophyly of Rhacophorus rhodopus,Theloderma and Philautus albopunctatus Inferred from Mitochondrial 16S rRNA Gene Sequences

测定了4个种(红蹼树蛙、黑蹼树蛙、白斑小树蛙和红吸盘小树蛙)共11个种群的16S rRNA基因片段.双斑树蛙、马来棱皮树蛙、越南棱皮树蛙以及日本溪树蛙的同源序列通过GenBank检索获得.去除所有插入、缺失及模糊位点后,比对序列长度为500 bp,其中变异位点115个,简约信息位点92个.以日本溪树蛙为外群,运用Bayesian法、MP法和ML法构建了系统发育树.结果表明红蹼树蛙和白斑小树蛙在种级水平上均不是单系.红蹼树蛙海南种群与双斑树蛙亲缘关系更近,并且来自云南不同地理种群的红蹼树蛙可以分为两大支系;越南棱皮树蛙与红吸盘小树蛙聚为一支,马来棱皮树蛙嵌套在白斑小树蛙不同地理种群中.进而认为白斑小树蛙是马来棱皮树蛙的同物异名,建议将红吸盘小树蛙并入棱皮树蛙属.

Non-monophyly of fish in the Sinipercidae (Perciformes) as inferred from cytochrome b gene

The sinipercids represent a group of 12 species of freshwater percoid fish, including nine in Siniperca and three species in Coreoperca. Despite several classification attempts and a preliminary molecular phylogeny, the phylogenetic relationships and systematic position of sinipercids remained still unsolved. The complete cytochrome b gene sequences from nine sinipercid species four non-sinipercid fish species were cloned, and a total of 12 cyt b sequences from 10 species of sinipercids and 11 cyt b sequences from 10 species of non-sinipercid fish also in Perciformes were included in the phylogenetic analysis. As expected, the two genera Siniperca and Coreoperca within sinipercids are recovered as monophyletic. However, nine species representing Moronidae, Serranidae, Centropomidae, Acropomatidae, Emmelichtyidae, Siganidae and Centrarchidae included in the present study are all nested between Coreoperca and Siniperca, which provides marked evidence for a non-monophyly of sinipercid fishes. Coreoperca appears to be closest to Centrachus representing the family Centrarchidae. Coreoperca whiteheadi and C. herzi are sibling species, which together are closely related to C. kawamebari. In the Siniperca, the node between S. roulei and the remaining species is the most ancestral, followed by that of S. fortis. S. chuatsi and S. kneri are sibling species, sister to S. obscura. However, the sinipercids do not seem to have a very clear phylogenetic history, for different methods of phylogenetic reconstruction result in different tree topologies, and the only conclusive result in favor of a paraphyletic origin of the two sinipercid genera is the parametric bootstrap test. The paraphyly of Sinipercidae may suggest that the "synapomorphs" such as cycloid scales, upon which this family is based, were independently derived at least twice within sinipercid fishes, and further study should be carried out to include the other two Siniperca species and to incorporate other genes.

The first non-mammalian CXCR3 in a teleost fish: Gene and expression in blood cells and central nervous system in the grass carp (Ctenopharyngodon idella)

A novel fish chemokine receptor gene, chemokine (C-X-C motif) receptor 3 (CXCR3)-like was isolated from the grass carp Ctenopharyngodon idella , with its full-length genomic sequence. The cDNA of grass carp CXCR3-like (gcCXCR3-like) consists of 1261 bp with a 49bp 5'-UTR and a 189 bp 3'-UTR. An open reading frame of 1023 bp encodes a 341-amino acid peptide, with seven transmembrane helices. The deduced amino acid sequence showed the same sequence identities (37.8%) with its counterparts in goat and human. The gcCXCR3-like gene consists of two exons, with one intervening intron, spaced over approximately 2 kb of genomic sequence. Phylogenetic analyses clearly demonstrated that the gcCXCR3-like resembles the CXCR3s of other vertebrates. Real-time PCR analysis showed that gcCXCR3-like was expressed in all tested organs except heart and the expression level of gcCXCR3-like was highest in brain. Flow cytometric analyses showed the positive rate of labelled leukocytes from the healthy grass carp was 17.3%, and the labelled leukocytes were divided into three types by cell sorting. Immunohistochemical localization revealed that gcCXCR3-like expressed in whole brain regions including cerebel, diencephalon, medulla oblongata, optic lobe, and rhinencephalon, and that the labelled leukocytes are actually populations of monocyte and/or phagocyte, lymphocyte and the granulocyte. It is considered that fish CXCR expression and their function may need to be investigated in both nervous and immune systems. (c) 2006 Elsevier Ltd. All rights reserved.

Pre-irradiation with low-dose C-12(6+) beam significantly enhances the efficacy of AdCMV-p53 gene therapy in human non-small lung cancer

The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to low-dose heavy ion beam enhances the suppression of AdCMV-p53 on non-small lung cancer (NSLC), the cells pre-irradiated or non-irradiated were infected with 20, 40 MOI of AdCMV-p53. Survival fraction and the relative biology effect (RBE) were determined by clonogenic assay. The results showed that the proportions of p53 positive cells in C-12(6+) beam induced AdCMV-p53 infected cells were more than 90%, which were significantly more than those in gamma-ray induced AdCMV-p53 infected cells. The pre-exposure to low-dose 12C6+ beam significantly prevented the G(0)/G(1) arrest and activated G(2)/M checkpoints. The pre-exposure to C-12(6+) beam significantly improved cell to apoptosis. RBEs for the C-12(6+)+ AdCMV-p53 infection groups were 30%-60%,20% -130% and 30%-70% more than those for the C-12(6+)_irradiated only, AdCMV-p53 infected only, and gamma-irradiation induced AdCMVp53 infected groups, respectively. The data suggested that the pre-exposure to low-dose C-12(6+) beam significantly promotes exogenous p53 expression in NSLC, and the suppression of AdCMV-p53 gene therapy on NSLC.

The Liquefaction and Displacement of Highly Saturated Sand under Water Pressure Oscillation

In order to investigate the characteristics of water wave induced liquefaction in highly saturated sand in vertical direction, a one-dimensional model of highly saturated sand to water pressure oscillation is presented based oil the two-phase continuous media theory. The development of the effective stresses and the liquefaction thickness are analyzed. It is shown that water pressure oscillating loading affects liquefaction severely and the developing rate of liquefaction increases with the decreasing of the sand strength or the increasing of the loading strength. It is shown also that there is obvious phase lag in the sand Column. If the sand permeability is non-uniform, the pore pressure and the strain rise sharply at which the smallest permeability occurs. This solution may explain Why the fracture occurs in the sand column in some conditions.

Liquefaction and Displacement of Saturated Sand Under Vertical Vibration Loading

In order to investigate the influence of the vertical vibration loading on the liquefaction of saturated sand, one dimensional model for the saturated sand with a vertical vibration is presented based on the two phase continuous media theory. The development of the liquefaction and the liquefaction region are analyzed. It is shown that the vertical vibration loading could induce liquefaction. The rate of the liquefaction increases with the increase of the initial limit strain or initial porosity or amplitude and frequency of loading, and increases with the decrease of the permeability or initial modulus. It is shown also that there is a phase lag in the sand column. When the sand permeability distribution is non-uniform, the pore pressure and the strain will rise sharply where the permeability is the smallest, and fracture might be induced. With the development of liquefaction, the strength of the soil foundation becomes smaller and smaller. In the limiting case, landslides or debris flows could occur.