Polychaete species captured in sediment traps moored in northwestern Mediterranean submarine canyons

Sediment traps were placed in the water column both inside and in the vicinity of three northwestern Mediterranean submarine canyons. The sediment traps with 12 rotary collectors were deployed on mooring lines 30 and 500 m above the sea floor, and were sampled fortnightly. Polychaete worms (Anelida) and hydromedusae (Cnidaria) were the most abundant zoological taxa captured. Whereas hydromedusae and three of the polychaete species were clearly planktonic organisms, 16 polychaete species were adult benthic forms without special adaptations for swimming, and sometimes also had a large biomass. Four of the 19 polychaete species are described as new species: Aricidea (Allia) longisetosa sp. nov. , Paradoneis hirsuta sp. nov. , Ophelina margaleffi sp. nov. , and Exogone (Parexogone) canyonincolae sp. nov. The rich collection of polychaetes obtained leads us to postulate that these animals are supported by a continuous flux of organic matter, and that they are adapted to the rigorous physical conditions that may occur between the seafloor and the bottom water. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 1–21.     

The land–atmosphere water flux in the tropics

Tropical vegetation is a major source of global land surface evapotranspiration, and can thus play a major role in global hydrological cycles and global atmospheric circulation. Accurate prediction of tropical evapotranspiration is critical to our understanding of these processes under changing climate. We examined the controls on evapotranspiration in tropical vegetation at 21 pan-tropical eddy covariance sites, conducted a comprehensive and systematic evaluation of 13 evapotranspiration models at these sites, and assessed the ability to scale up model estimates of evapotranspiration for the test region of Amazonia. Net radiation was the strongest determinant of evapotranspiration (mean evaporative fraction was 0.72) and explained 87% of the variance in monthly evapotranspiration across the sites. Vapor pressure deficit was the strongest residual predictor (14%), followed by normalized difference vegetation index (9%), precipitation (6%) and wind speed (4%). The radiation-based evapotranspiration models performed best overall for three reasons: (1) the vegetation was largely decoupled from atmospheric turbulent transfer (calculated from Ω decoupling factor), especially at the wetter sites; (2) the resistance-based models were hindered by difficulty in consistently characterizing canopy (and stomatal) resistance in the highly diverse vegetation; (3) the temperature-based models inadequately captured the variability in tropical evapotranspiration. We evaluated the potential to predict regional evapotranspiration for one test region: Amazonia. We estimated an Amazonia-wide evapotranspiration of 1370 mm yr⁻¹, but this value is dependent on assumptions about energy balance closure for the tropical eddy covariance sites; a lower value (1096 mm yr⁻¹) is considered in discussion on the use of flux data to validate and interpolate models.     

Organic Matter Stable Isotope (δ13C, δ15N) Response to Historical Eutrophication of Lake Taihu, China

We explored the use of carbon and nitrogen isotope ratios (δ¹³C, δ¹⁵N) in sediment organic matter as proxy indicators of historical changes in the trophic state of Lake Taihu, the third largest freshwater lake in China. Stable isotope signatures in four sediment cores spanning the 20th century were compared with instrumental records of lake-water trophic state. The comparative study shows that, between ∼ ∼1950 and 1990 AD, the δ¹³C and δ¹⁵N of sediment organic matter throughout Lake Taihu increased along the trophic gradient from oligotrophy to eutrophy due to biological isotopic fractionation. However, in the 1990s, the trophic state of Lake Taihu diverged into two different trophic systems, a hypereutrophic western Lake Taihu dominated by blue-green algae and a mesoeutrophic eastern Lake Taihu dominated by vascular aquatic plants. During the post-1990 AD shift from mesoeutrophic to hypereutrophic state in western Lake Taihu, organic matter δ¹³C and δ¹⁵N decreased sharply in response to pronounced shifts in the aquatic ecosystem. The results indicate that ¹³C-depleted phytoplankton replaced macrophytes in western Lake Taihu. δ¹⁵N values in western Lake Taihu also decreased because of N₂ fixation by cyanobacteria in this highly productive ecosystem. By contrast, in eastern Lake Taihu, organic matter δ¹³C and δ¹⁵N values show a post-1990 AD trend towards slightly lower values, but they remain higher than the long-term average. This recent ¹³C–enrichment of organic matter indicates that periods of high productivity in the restricted eastern sub-basin of Lake Taihu limited aqueous CO₂ availability, causing a decrease in isotopic discrimination during photosynthesis. After ∼ ∼1990 AD, organic matter δ¹⁵N values for eastern Lake Taihu only dropped slightly, suggesting that the contribution of phytoplankton to the sediment organic matter increased slightly. Taken together, the results indicate that nitrogen-fixing cyanobacteria probably played a much smaller role in primary productivity in this part of eastern Lake Taihu, compared with western Lake Taihu. Despite the complexity of carbon and nitrogen cycles in lakes, the agreement between the stable isotope signatures and instrumental records for Lake Taihu suggests that δ¹³C and δ¹⁵N in sediment organic matter are capable of recording important shifts in the spatial and temporal evolution of lake-water trophic state.     

Overexpression of PRE1 and its homologous genes activates Gibberellin-dependent responses in Arabidopsis thaliana

Gibberellins control various aspects of growth and development. Here, we identified a gene, designated paclobutrazol resistance1 (PRE1), by screening Arabidopsis activation-tagged lines. PRE1 encodes a helix-loop-helix protein and belongs to a small gene family. Physiological and genetic analysis indicated that overexpression of PRE1 altered various aspects of gibberellin-dependent responses such as germination, elongation of hypocotyl/petiole, floral induction and fruit development, and suppressed gibberellin-deficient phenotypes of the ga2 mutant. Expression of some gibberellin-responsive genes was also affected by PRE1. Expression of PRE1 was shown to be early gibberellin inducible in the wild-type plants and under control of SPY and GAI, upstream negative regulators of gibberellin signaling. The shortened hypocotyl length phenotype of the gai-1 mutant was suppressed by PRE1 overexpression. Ectopic overexpression of each of the four PRE1-related genes conferred pleiotropic phenotypes similar to PRE1 overexpression, indicative of overlapping functions among the PRE gene family. Our results of gain-of-function studies suggest that PRE genes may have a regulatory role in gibberellin-dependent development in Arabidopsis thaliana.     

Nuclear Multidrug-Resistance Related Protein 1 Contributes to Multidrug-Resistance of Mucoepidermoid Carcinoma Mainly via Regulating Multidrug-Resistance Protein 1: A Human Mucoepidermoid Carcinoma Cells Model and Spearman's Rank Correlation Analysis

Background

Multidrug resistance-related protein 1 (MRP1/ABCC1) and multidrug resistance protein 1 (MDR1/P-glycoprotein/ABCB1) are both membrane-bound drug transporters. In contrast to MDR1, MRP1 also transports glutathione (GSH) and drugs conjugated to GSH. Due to its extraordinary transport properties, MRP1/ABCC1 contributes to several physiological functions and pathophysiological incidents. We previously found that nuclear translocation of MRP1 contributes to multidrug-resistance (MDR) of mucoepidermoid carcinoma (MEC). The present study investigated how MRP1 contributes to MDR in the nuclei of MEC cells.

Methods

Western blot and RT-PCR was carried out to investigate the change of multidrug-resistance protein 1 (MDR1) in MC3/5FU cells after MRP1 was downregulated through RNA interference (RNAi). Immunohistochemistry (IHC) staining of 127 cases of MEC tissues was scored with the expression index (EI). The EI of MDR1 and MRP1 (or nuclear MRP1) was analyzed with Spearman''s rank correlation analysis. Using multiple tumor tissue assays, the location of MRP1 in other tissues was checked by HIC. Luciferase reporter assays of MDR1 promoter was carried out to check the connection between MRP1 and MDR1 promoter.

Results

MRP1 downregulation led to a decreased MDR1 expression in MC3/5FU cells which was caused by decreased activity of MDR1 promoter. IHC study of 127 cases of MEC tissues demonstrated a strong positive correlation between nuclear MRP1 expression and MDR1 expression. Furthermore, IHC study of multiple tumor tissue array sections showed that although nuclear MRP1 widely existed in MEC tissues, it was not found in normal tissues or other tumor tissues.

Conclusions

Our findings indicate that nuclear MRP1 contributes to MDR mainly through regulating MDR1 expression in MEC. And the unique location of MRP1 made it an available target in identifying MEC from other tumors.     

Methyl farnesoate induced ovarian maturation in the spider crab,Libinia emarginata

Summary

To overcome the problem of getting crustaceans to reproduce in captivity, eyestalk ablation or X-organ sinus gland removal is commonly utilized in commercially important species such as shrimp. We have investigated the effect of unilateral and bilateral eyestalk ablation on methyl farnesoate (MF) production by mandibular organs (MOs) and on ovarian maturation in female spider crabs Libinia emarginata, a useful model since these animals are in a terminal molt and are devoid of a functional Y-organ. Non-reproductive, over-wintering female L. emarginata were induced to be reproductive by feeding and increasing the holding temperature to stimulate the endocrine system. In addition, we removed X-organ sinus glands by eyestalk ablation either unilaterally (UEA) or bilaterally (BEA) to further stimulate MF synthesis by MOs. Endogenous MF in the hemolymph was extracted and quantified by means of HPLC and in some cases by GC/MS. Oocyte growth and egg quality were studied simultaneously to determine how they were related to MF levels found during vitellogenesis. The initial MF concentration in unablated controls was low, 0.31 ng/ml of hemolymph, and this increased (p<0.05) to about 1 ng/ml by 2 weeks, remaining at about that level for the remainder of the experiment. Eyestalk ablation significantly stimulated MF concentrations by week 1 to nearly 2 and 3.5ng/ml in the UEA (p <0.01) and BEA (p <0.001) animals, respectively. Oocytes appeared to respond to increased MF levels, as ovarian maturation was initiated from the point at which MF increased (p <0.05). Thereafter, the rate of oocyte growth was directly correlated with the extent of elevation of MF. The gonado-somatic index [(GSI) = gonad weight/body weight × 100] of controls at the start was about 1.5 and increased to 6.5 by week 4. Mature oocytes were reached at a GSI around 7. Oocyte maturation was accomplished at week 2 in BEA, week 3 in UEA, and later than week 4 in controls. After maturation, oocytes started to degrade in some ablated animals, particularly in the bilaterally ablated ones where the highest MF concentrations were observed. These data indicate that MF elevations are required for stimulating ovarian maturation in Crustacea. MF appears to accelerate gonad development during the vitellogenic process, but may be deleterious at high concentrations. These results have a significant and important application and implications for aquaculture.     

Observation of some key stages of the embryonic development of Biomphalaria straminea (Dunker, 1848) (Molluska,Planorbidae)

Summary

Biomphalaria straminea is a freshwater snail and one of the intermediate hosts of the trematode parasite which causes schistosomiasis in Brazil. The main stages of embryonic development were analyzed with confocal laser scanning microscopy (CLSM), using the fluorescent probe DiOC and Nile Red as a vital stain in in vivo preparations. In fixed preparations nuclei were stained by the Feulgen reaction or the fluorescent DNA probe, Höechst 33342. Results obtained from the analysis of embryos at the stages of early cleavage, morula, blastula, gastrula, early trocophore and veliger showed that these stages are similar to those described for Biomphalaria glabrata and Biomphalaria tenagophila. CLSM optical sections of early trochophore showed important morphological structures such as the blastopore, stomodeum and shell gland; and in early veliger, internal organs such as the esophagus, stomach and male and female ducts were also clearly identified.     

大肠杆菌 LT B亚基基因表达载体对犬细小病毒VP2 DNA疫苗免疫应答的增强作用

【目的】通过融合基因表达载体和共免疫基因表达载体研究大肠杆菌不耐热肠毒素(LT)B亚基基因对犬细小病毒VP2DNA疫苗免疫应答的影响。【方法】提取大肠杆菌44815菌株基因组DNA,通过PCR方法从基因组DNA中扩增LTB基因,同时采用PCR方法从含有犬细小病毒VP2基因的质粒中扩增VP2的主要抗原表位基因(VP2-70,编码70个氨基酸)。将上述基因分别连接到含有人CD5信号肽序列的载体pcDNA-CD5sp上,分别构建成它们的分泌型真核表达载体,pcDNA-CD5sp-LTB和pcDNA-CD5sp-VP2-70。再利用酶切连接的方法构建LTB与VP2-70融合的真核表达载体pcDNACD5sp-LTB-VP2-70。然后用pcDNACD5sp-VP2-70(VP2-70组)、pcDNACD5sp-LTB-VP2-70(VP2-LTB融合组)、pcDNA-CD5sp-LTB/pcDNACD5sp-VP2-70(VP2-LTB共免疫组)和pcDNA3.1A(空载体对照组)分别免疫小鼠。免疫后用间接ELISA检测不同时间小鼠血清的抗体水平,用MTT方法检测小鼠免疫5周后脾脏淋巴细胞的增殖活性。【结果】经过测序表明本研究扩增的LTB和VP2基因序列和构建的相关表达载体结构正确。通过Western-blot检测证明构建的表达载体均能介导相应基因在真核细胞进行分泌表达。ELISA检测结果表明,3组实验组小鼠接受VP2DNA疫苗免疫后均能产生特异的体液免疫应答反应,特别是VP2-LTB基因融合组小鼠的抗体水平在第5周时高达1:5120,明显高于其它两组(P<0.01)。3组免疫小鼠抗体的亚型均表现IgG1抗体水平明显高于IgG2a抗体水平(P<0.01)。淋巴细胞增殖实验结果表明,在ConA的刺激下,3组免疫小鼠的淋巴细胞刺激指数均明显高于对照组(P<0.01),说明VP2DNA疫苗能够引起淋巴细胞的增殖。但3组免疫小鼠之间的刺激指数没有明显差异(P>0.05)。【结论】在小鼠体内,LTB基因表达载体可明显提高CPVVP2DNA疫苗的体液免疫应答水平。     

Hybrid speciation in sparrows II: a role for sex chromosomes?

Homoploid hybrid speciation in animals is poorly understood, mainly because of the scarcity of well‐documented cases. Here, we present the results of a multilocus sequence analysis on the house sparrow (Passer domesticus), Spanish sparrow (P. hispaniolensis) and their proposed hybrid descendant, the Italian sparrow (P. italiae). The Italian sparrow is shown to be genetically intermediate between the house sparrow and Spanish sparrow, exhibiting genealogical discordance and a mosaic pattern of alleles derived from either of the putative parental species. The average variation on the Z chromosome was significantly reduced compared with autosomal variation in the putative parental species, the house sparrow and Spanish sparrow. Additionally, divergence between the two species was elevated on the Z chromosome relative to the autosomes. This pattern of variation and divergence is consistent with reduced introgression of Z‐linked genes and/or a faster‐Z effect (increased rate of adaptive divergence on the Z). F_ST‐outlier tests were consistent with the faster‐Z hypothesis: two of five Z‐linked loci (CHD1Z and PLAA) were identified as candidates for being subject to positive, divergent selection in the putative parental species. Interestingly, the two latter genes showed a mosaic pattern in the (hybrid) Italian sparrow; that is, the Italian sparrow was found to be fixed for Spanish sparrow alleles at CHD1Z and to mainly have house sparrow alleles at PLAA. Preliminary evidence presented in this study thus suggests that sex chromosomes may play a significant role in this case of homoploid hybrid speciation.