祁连山5种典型灌丛土壤生态化学计量特征

土壤C、N、P生态化学计量特征是体现生态系统变化过程的重要依据。该研究以分布于祁连山北麓中段的甘青锦鸡儿、鲜黄小檗、金露梅、鬼箭锦鸡儿、吉拉柳等5种典型灌丛群落为研究对象,通过野外调查采样,测定土壤有机C、N、P含量,分析了不同灌丛群落土壤C、N、P含量及其生态化学计量比的垂直分布特征,并探讨了各指标间的耦合关系,为祁连山地区土壤-植物养分关系及退化植被恢复与重建提供理论依据。结果表明:(1)祁连山北麓中段5种灌丛群落土壤有机C(45.29 g/kg)、全N(3.85 g/kg)、全P含量(0.70 g/kg)较高,均高于全国平均水平。(2)相关性分析表明,土壤有机C与全N之间呈极显著正相关(P0.01),但土壤有机C与全P以及全N与全P之间没有明显的相关性,且土壤C、N含量变化几乎完全同步。(3)各灌丛类型土壤有机C、全N含量均表现为表层高于下层,而全P含量土层间差异不显著;各灌丛群落土壤有机C、全N含量均随土层加深呈现"倒金字塔"的分布格局,但不同灌丛类型全P含量随土层加深的变化规律却不一致,且土层对全P含量的影响不显著。(4)5种灌丛群落土壤整体C∶N、C∶P、N∶P(11.29、66.99、5.67)均低于全国平均水平,各灌丛群落土壤C∶P、N∶P随土层加深均呈不同程度的下降趋势,但不同灌丛群落土壤C∶N随土层加深的变化规律有所不同。(5)土壤有机C、全N与C∶N、C∶P、N∶P之间均具有极显著的二次函数关系(P0.01),土壤全P与C∶N、C∶P、N∶P之间关系不显著。研究认为,祁连山北麓中段土壤C∶N和P含量的稳定性较高(CV=3.99%和2.66%),C∶P、N∶P是判断研究区限制性养分的重要指标,祁连山北麓中段灌丛群落土壤主要受N素的限制。     

贵州省凤仙花属6个新记录种

报道了贵州省凤仙花属（Impatiens）6个新记录种（含1变种）,分别是锐齿凤仙花（Impatiens arguta Hook.f.& Thomson.）、线萼凤仙花（Impatiens linearisepala S.Akiyama, H.Ohba & S.K.Wu）、川鄂凤仙花（Impatiens fargesii Hook.f.）、林生凤仙花（Impatiens lucorum Hook.f.）、雅致黄金凤（Impatiens siculifer var. mitis Lingelsheim & Borza）和田林凤仙花（Impatiens tianlinensis S.X.Yu & L.J.Zhang）。该文提供了新记录种形态特征照片和地理分布,凭证标本保存于贵州大学林学院树木标本室（GZAC）。     

EIF1A depletion restrains human pituitary adenoma progression

EIF1A encodes a translation initiation factor in eukaryocyte and aberrant expression of EIF1A is deemed to be associated with dysfunctions in intracranial diseases. The goal of this research was to explore the impacts of EIF1A on progression of human pituitary adenoma (PA). We employed immunohistochemistry to assess the expression of EIF1A in PA and para-carcinoma tissues. After constructing EIF1A-knockdown cell models via lentivirus infection, we examined cell proliferation through CCK-8 assay and Celigo cell counting assay. Flow cytometry was utilized to detect cell apoptosis and the migration ability of experimental cells was estimated using wound-healing assay and Transwell assay. The activity of the apoptosis-related factor, Caspase 3, was also examined via Caspase 3 activity assay. Lastly, in vivo xenograft mouse models were established to verify findings derived from in vitro cell models. Our results affirmed upregulation of EIF1A in PA cells and revealed that depletion of EIF1A could seriously limit cell proliferation and weaken the capacity of cell migration, and also enhance apoptosis of tumor cells. Mechanistically, degradation in cell growth mediated by EIF1A knockdown may involve in activation of MAPK signaling but inactivation of PI3K/AKT signaling pathway. This study indicates EIF1A plays a prominent role in facilitating tumor cell proliferation and migration which may further contribute to PA progression.Key words: EIF1A, Pituitary adenoma, Cell proliferation, Cell migration, MAPK     

A missense mutation in PPARD causes a major QTL effect on ear size in pigs

Chinese Erhualian is the most prolific pig breed in the world. The breed exhibits exceptionally large and floppy ears. To identify genes underlying this typical feature, we previously performed a genome scan in a large scale White Duroc × Erhualian cross and mapped a major QTL for ear size to a 2-cM region on chromosome 7. We herein performed an identical-by-descent analysis that defined the QTL within a 750-kb region. Historically, the large-ear feature has been selected for the ancient sacrificial culture in Erhualian pigs. By using a selective sweep analysis, we then refined the critical region to a 630-kb interval containing 9 annotated genes. Four of the 9 genes are expressed in ear tissues of piglets. Of the 4 genes, PPARD stood out as the strongest candidate gene for its established role in skin homeostasis, cartilage development, and fat metabolism. No differential expression of PPARD was found in ear tissues at different growth stages between large-eared Erhualian and small-eared Duroc pigs. We further screened coding sequence variants in the PPARD gene and identified only one missense mutation (G32E) in a conserved functionally important domain. The protein-altering mutation showed perfect concordance (100%) with the QTL genotypes of all 19 founder animals segregating in the White Duroc × Erhualian cross and occurred at high frequencies exclusively in Chinese large-eared breeds. Moreover, the mutation is of functional significance; it mediates down-regulation of β-catenin and its target gene expression that is crucial for fat deposition in skin. Furthermore, the mutation was significantly associated with ear size across the experimental cross and diverse outbred populations. A worldwide survey of haplotype diversity revealed that the mutation event is of Chinese origin, likely after domestication. Taken together, we provide evidence that PPARD G32E is the variation underlying this major QTL.     

Effect of Formic Acid on Conversion of Fructose to 5-Hydroxymethylfurfural in Aqueous/Butanol Media

Acid-catalyzed dehydration of carbohydrates into 5-hydroxymethylfurfural (HMF), a valuable biomass-derived intermediate, has received increasing attention. Efficient methods for HMF production are needed for successful commercialization of HMF in the near future. A new process for the dehydration of sugars into 5-hydroxymethylfurfural in aqueous/butanol media enhanced by using formic acid was developed. The effects of formic acid concentration, reaction temperature, and reaction time on the fructose conversion and HMF yield showed the significant influences of these process variables. The optimum conditions were found to be 2.5?mol/L formic acid concentration, 170°C and 70?min. Under such conditions, a fructose conversion of 98.3% with a HMF yield of 69.2% was achieved. The application of the butanol solvent and formic acid led to the conversion of fructose to HMF with high yield. The catalytic system in this study has prospects for commercial application due to its less corrosion and convenient downstream separation.     

Accumulation of β-catenin by lithium chloride in porcine myoblast cultures accelerates cell differentiation

The Wnt/β-catenin signaling pathway regulates cell proliferation and differentiation to determine cell fate during embryogenesis. Lithium chloride (LiCl) is known to activate canonical Wnt signaling by inhibiting glycogen synthetase kinase-3β and consequently stabilizing free cytosolic β-catenin. To understand the role of the Wnt/β-catenin pathway in the regulation of porcine myoblast differentiation, we studied the effects of LiCl on cultured porcine myoblasts and β-catenin expression. A supplementation of 25 mM LiCl induced myoblast differentiation into myotubes over 3 days of culture. By semi-quantitative RT-PCR analyses, levels of mRNA encoding MyoD, Myogenin, Myf5 and several Wnt-responsive genes in the cultured myoblast cells were significantly increased after LiCl treatment. Using Western blotting and immunofluorescence analysis, we found that the protein levels of β-catenin were consistently increased by LiCl. Meanwhile, phosphorylated GSK-3β at Ser9 levels were also increased as an indicator of GSK-3β inactivation. Additionally, the nuclear staining of endogenous β-catenin was also significantly increased in porcine myoblasts 48 h after LiCl treatment. These results provided additional evidence that Wnt/β-catenin is a significant pathway that regulates myogenic differentiation. An enhanced level of β-catenin plays a positive role in porcine myoblast differentiation.     

钙对香蕉采后果实呼吸的影响

本实验对香蕉成熟过程中水溶性钙的变化及CaCl_2溶液真空浸渗处理对香蕉果实呼吸作用的影响进行研究,结果表明,香蕉成熟期间,水溶性钙含量随成熟度的提高而增加,果实呼吸跃变上升前期,水溶性钙的增加尤为明显,果皮和果肉中水溶性钙含量与采后成熟天数呈正相关。以0.05mol/l和0.1mol/l CaCl_2溶液真空浸渗,可使香蕉果实呼吸跃变高峰延迟,但没有明显降低跃变峰值。     

龙眼果实防腐保鲜技术研究

近几年来,我们探讨了不同的贮藏温度、化学防腐剂、气体组分、包装容器及包装方法对不同品种龙眼果实的防腐保鲜效果。结果表明:龙眼品种间的耐贮性有很大差异,按耐贮性排列:泉州本>乌龙岭>普明庵>福眼>赤壳>水涨;最佳的保鲜贮藏温度为3～4℃;仲丁胺、仲丁胺+赤霉素、多菌灵、甲基托布津、苯甲酸、特克多、FISB-1和FISB-2等不同化学防腐剂对泉州本的防腐效果,以FISB-1和FISB-2防腐效果最佳,贮藏40天,好果率分别为95.0％和95.2％,其他防腐剂处理的好果率为80.7％～86.5％;气调贮藏,CO_2为4％～6％,O_2为6％～8％的气体组分可延长贮藏寿命,降低龙眼果实自身损耗;包装容器以塑料周转箱套薄膜袋气调贮藏效果最佳。     

Understanding the key factors for enzymatic conversion of pretreated lignocellulose by partial least square analysis

The relationship between the physicochemical properties of lignocellulosic substrates and enzyme digestion is still not well known. After different pretreatments, cellulase hydrolysis and measurements of physicochemical characteristics by column solute exclusion, particle size analysis, X‐ray diffraction, Fourier transform infrared spectroscopy and solid state ¹³C nuclear magnetic resonance were performed in this study. Partial least squares was then applied to seek the key factors limiting the rate and extent of cellulose digestion. According to the PLS results, the most important factor for cellulose digestion was accessible interior surface area, followed by delignification and the destruction of the hydrogen bonds. The cellulose digestion at 2 and 24 hr were improved with the increased accessibility of interior surface area to the reporter molecules of 5.1‐nm diameter. Removal of lignin and breaking of hydrogen bonds were also found to significantly promote cellulose conversion. Other properties, including the breakdown of intramolecular hydrogen bonds, cellulose crystallinity, and hemicellulose content, had less effect on the efficiency of enzymatic hydrolysis. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010