Root decomposition of <Emphasis Type="Italic">Artemisia halodendron</Emphasis> and its effect on soil nitrogen and soil organic carbon in the Horqin Sandy Land,northeastern China

Root decomposition is a critical feedback from the plant to the soil, especially in sandy land where strong winds remove aboveground litter. As a pioneer shrub in semi-mobile dunes of the Horqin sandy land, Artemisia halodendron has multiple effects on nutrient capture and the microenvironment. However, its root decomposition has not been studied in terms of its influence on soil organic carbon (SOC) and nitrogen (N). In this study, we buried fine (≤2 mm) and coarse roots in litterbags at a depth of 15 cm below semi-mobile dunes. We measured the masses remaining and the C and N contents at intervals during 434 days of decomposition. The soils below the litterbags were then divided into layers and sampled to measure the SOC and N contents. After rapid initial decomposition, both coarse and fine roots decomposed slowly. After 53 days, 36.2 % of coarse roots and 39.8 % of fine roots had decomposed. In contrast, only 18.4 % of coarse roots and 30.5 % of fine roots decomposed in the following 381 days. Fine roots decomposed significantly faster, and their decomposition rate after the initial rapid decay was strongly related to climate (R ² = 0.716, P < 0.05). Root decomposition increased SOC and N contents below the litterbags, with larger effects for fine roots. The SOC content was more variable between soil layers than the N content. Thus, decomposition of A. halodendron roots cannot be ignored when studying SOC and N feedbacks from plants to the soil, particularly for fine roots.     

谷子不育系及其相应可育系小孢子发育的细胞学观察

以谷子2个品种的不育系及其保持系为材料,对其小孢子发育的细胞形态学进行了观察研究。结果表明:昭盟A花药的外部形态及花粉母细胞的发育过程与昭盟B相似,能形成外观正常的三核花粉,但其花药不能开裂散粉。石炮A表现出了败育时间和方式的多样性,且不育系与保持系间在花药长度上有显著差异。此外,两种不育系的维管束都表现出不同程度的发育不良。不良程度与药囊退化程度相关。     

microRNA-501-5p promotes cell proliferation and migration in gastric cancer by downregulating LPAR1

In spite of the achievement in treatment, the gastric cancer (GC) mortality still remains high. MicroRNAs (miRNAs) are a group of small noncoding RNAs that play a crucial part in tumor progression. In this study, we explored the expression and function of microRNA-501-5p (miR-501-5p) in GC cell lines. Quantitative real-time polymerase chain reaction assay results suggested that miR-501-5p was significantly upregulated in GC tissues and cell lines. And, the Cell Counting Kit-8 colony formation and cell migration assay results showed that the downregulation of miR-501-5p decreased GC cell proliferation and migration. Besides that, we found that GC cell cycle was arrested in G2 phase and cell apoptosis rate was increased by silencing the expression of miR-501-5p in GC cell lines using the flow cytometry. We also found that miR-501-5p could directly target lysophosphatidic acid receptor 1 (LPAR1) and negatively regulate LPAR1 expression in GC cell lines by performing dual-luciferase reporter gene assay and Western blot analysis. And, LPAR1 was significantly downregulated in GC tissues and inversely correlated with miR-501-5p expression. Furthermore, LPAR1 downregulation promoted cell proliferation and migration, which were attenuated by cotransfection of miR-501-5p inhibitor in GC cells. In conclusion, miR-501-5p can promote GC cell proliferation and migration by targeting and downregulating LPAR1. miR-501-5p/LPAR1 may become a potential therapeutic target for GC treatment.     

Modulation of mouse neural crest cell motility by N-cadherin and connexin 43 gap junctions.

Connexin 43 (Cx43alpha1) gap junction has been shown to have an essential role in mediating functional coupling of neural crest cells and in modulating neural crest cell migration. Here, we showed that N-cadherin and wnt1 are required for efficient dye coupling but not for the expression of Cx43alpha1 gap junctions in neural crest cells. Cell motility was found to be altered in the N-cadherin-deficient neural crest cells, but the alterations were different from that elicited by Cx43alpha1 deficiency. In contrast, wnt1-deficient neural crest cells showed no discernible change in cell motility. These observations suggest that dye coupling may not be a good measure of gap junction communication relevant to motility. Alternatively, Cx43alpha1 may serve a novel function in motility. We observed that p120 catenin (p120ctn), an Armadillo protein known to modulate cell motility, is colocalized not only with N-cadherin but also with Cx43alpha1. Moreover, the subcellular distribution of p120ctn was altered with N-cadherin or Cx43alpha1 deficiency. Based on these findings, we propose a model in which Cx43alpha1 and N-cadherin may modulate neural crest cell motility by engaging in a dynamic cross-talk with the cell's locomotory apparatus through p120ctn signaling.     

‘红阳’猕猴桃叶盘高频直接再生体系的建立

以‘红阳’猕猴桃雌株幼叶为外植体,直接诱导产生不定芽,并对不定芽增殖以及生根体系进行优化,建立了高频再生体系。结果表明,在MS+3.0 mg/L BA+1.0 mg/L NAA培养基中,不定芽诱导率达100％,平均出芽数达18.67个/叶盘;在MS+2.0 mg/L BA+1.0 mg/L NAA+0.1 mg/L GA3培养基中,增殖率达100％,1~6代不定芽平均繁殖系数达8.63;不定芽在1/2 MS+0.8 mg/L IBA培养基中培养15 d,然后继代至含1/2 MS液体培养基的珍珠岩中培养15 d,生根率达100％,且其根系发育良好;98株试管苗移栽到土壤盆钵中,成活95株,成活率达96.94％。本试验成功建立了红阳猕猴桃叶片高频直接再生体系,该体系诱导产生不定芽周期短,出芽率高,不定芽增殖系数大,生根率高且根系发达,为红阳猕猴桃试管苗的工厂化生产和遗传转化奠定了基础。     

Use of Ca+2 to re-aggregate lipopolysaccharide (LPS) in hemoglobin solutions and the subsequent removal of endotoxin by ultrafiltration

Divalent cations such as Ca⁺² can act as bridges between lipopolysaccharide subunits causing large vesicles to form. During a two-stage ultrafiltration Ca⁺² re-aggregated lipopolysaccharide subunits in protein solutions into large vesicles that could not pass a 300,000 nominal molecular weight cut-off ultrafiltration membrane. Such re-aggregation occurred at concentration ratio of hemoglobin Ao / lipopolysaccharide equal to or less than 17.0, or at concentration ratio of Ca⁺² / hemoglobin Ao / lipopolysaccharide equal to or greater than 8.5.     

产高活性抗凝溶栓双活性蛋白的短小芽孢杆菌的筛选及鉴定

摘要:【目的】筛选可产生抗血栓活性物质的细菌。【方法】利用VY/4平板、酪蛋白平板从水样、土样、兔粪、羊粪、朽木等20多个样品中筛选目的菌株;利用纤维蛋白平板和纤维蛋白试管检测抗血栓活性;利用形态学特征、理化性质、16S rRNA序列同源性鉴定目的菌株。【结果】得到5株可产生抗血栓活性物质的细菌,重点研究了菌株LDS33,发现其分泌的胞外蛋白在纤维蛋白平板上和纤维蛋白试管中均显示出强烈的溶栓活性,通过试管法发现此蛋白质同时具有较强的抗凝活性。结合形态学、理化性质、16S rDNA序列及进化树分析,发现该菌株属于硬壁菌门芽孢杆菌目芽孢杆菌科芽孢杆菌属的短小芽孢杆菌,将其命名为Bacillus pumilus LDS.33。【结论】短小芽孢杆菌LDS33可产生高活性的抗凝溶栓双活性蛋白。     

Compensatory increase in hepatic lipogenesis in mice with conditional intestine-specific Mttp deficiency

Microsomal TG transfer protein (MTTP) is required for the assembly and secretion of TG (TG)-rich lipoproteins from both enterocytes and hepatocytes. Liver-specific deletion of Mttp produced a dramatic reduction in plasma very low density lipoprotein-TG and virtually eliminated apolipoprotein B100 (apoB100) secretion yet caused only modest reductions in plasma apoB48 and apoB48 secretion from primary hepatocytes. These observations prompted us to examine the phenotype following intestine-specific Mttp deletion because murine, like human enterocytes, secrete virtually exclusively apoB48. We generated mice with conditional Mttp deletion in villus enterocytes (Mttp-IKO), using a tamoxifen-inducible, intestine-specific Cre transgene. Villus enterocytes from chow-fed Mttp-IKO mice contained large cytoplasmic TG droplets and no chylomicron-sized particles within the secretory pathway. Chow-fed, Mttp-IKO mice manifested steatorrhea, growth arrest, and decreased cholesterol absorption, features that collectively recapitulate the phenotype associated with abetalipoproteinemia. Chylomicron secretion was reduced dramatically in vivo, in conjunction with an approximately 80% decrease in apoB48 secretion from primary enterocytes. Additionally, although plasma and hepatic cholesterol and TG content were decreased, Mttp-IKO mice demonstrated a paradoxical increase in both hepatic lipogenesis and very low density lipoprotein secretion. These findings establish distinctive features for MTTP involvement in intestinal chylomicron assembly and secretion and suggest that hepatic lipogenesis undergoes compensatory induction in the face of defective intestinal TG secretion.     

应用组织芯片技术研究MMP-9和PCNA在宫颈癌组织中的表达及其意义

目的探讨MMP-9和PCNA在宫颈癌组织中的联合表达、相关性及其临床意义。方法采用组织芯片和免疫组化技术检测143例宫颈浸润癌(ICC)、20例癌旁正常宫颈上皮(NCE)中MMP-9和PCNA的表达,统计分析MMP-9、PCNA表达与病理分级、临床分期和淋巴结转移等临床病理因素的关系。结果 MMP-9、PCNA在宫颈癌组织中的阳性率分别为89.5%(128/143)和93.7%(134/143),较正常宫颈组织中的阳性率40.0%(8/20)和15.0%(3/20)显著增高(P=0.000)。MMP-9的表达与病理分级(r=0.342,P=0.000)、淋巴结转移(r=0.197,P=0.018)和间质浸润深度(r=0.203,P=0.015)呈正相关。PCNA表达与临床分期(r=0.228,P=0.006)、病理分级(r=0.330,P=0.000)呈正相关。MMP-9和PCNA在宫颈癌组织中的表达强度呈正相关(r=0.228,P=0.006),二者表达一致的比例高达87.41%(125/143)。结论MMP-9和PCNA在宫颈癌中的异常表达与肿瘤的分化、侵袭和发展密切相关,联合检测二者的表达对于进一步理解宫颈癌的生物学行为和判断预后有一定价值。