放线菌素D和环已亚胺对伊贝母胚性愈伤组织中胚性细胞团和球形胚发生及大分子代谢动态的影响

伊贝母(F.pallidiflora Schrenk)胚性愈伤组织接种于NAA 1.0mg/L+6-BA2.0 mg/L的MS培养基上,在培养10天前可产生大量单细胞到多细胞胚性细胞团,培养10至15天,逐渐形成大量球形胚。利用这样一个实验体系,在培养0、1、2、3和4天后加入放线菌素D(AMD,20μg/ml)和环己亚胺(CHM,20μg/ml),继续培养至第6天,分析大分子代谢动态和观察胚性细胞团的形成情况;培养6和10天后加入同样浓度的AMD和CHM。继续培养至第15天,分析大分子代谢动态及观察球形胚形成情况。结果表明:(1)培养0、1、2、3和4天加入AMD的分别抑制胚性细胞团的100%、63%和45%,加入CHM的抑制100%、85%和75%,培养6和10天后加入CHM抑制球形胚的100%和75%;(2)DNA、RNA和蛋白质在胚性细胞团和球形胚形成时出现两个峰值,其中RNA变化剧烈,最早出现峰值。AMD和CHM分别抑制RNA和蛋白质的合成;(3)过氧化物酶同工酶带在胚性细胞团和球形胚形成过程中顺序表达,AMD和CHM分别在转录和转译水平上对其进行规律性抑制。根据以上结果,本文对伊贝母体细胞胚胎发生的机制进行了初步讨论。     

紫米基因与RFLP标记的连锁分析

选用种皮呈紫黑色的水稻体细胞无性系变异体黑珍米和其种皮呈无色的原始亲本Ｂａｓｍａｔｉ３７０配制组合,同时应用１２１个ＤＮＡ探针检测了黑珍米与Ｂａｓｍａｔｉ３７０之间的ＲＦＬＰ。应用Ｆ２和Ｆ３群体研究了紫色种皮的遗传控制。结果表明,有一个显性主效基因控制着黑珍米和Ｂａｓｍａｔｉ３７０在种皮颜色上的差异。通过多态性ＤＮＡ探针与种皮颜色的共分离分析,发现该基因与水稻第四染色体上的ＤＮＡ标记ＲＧ３２９和ＲＧ２１４连锁,与ＲＧ３２９和ＲＧ２１４的遗传图距分别为１８．９ｃＭ和２６．３ｃＭ。     

The Leptin Gene Family and Colorectal Cancer: Interaction with Smoking Behavior and Family History of Cancer

Background

Pathologic condition associated with metabolic syndrome traits seems to increase the risk of colorectal cancer. One mechanism underlying this relationship may involve the growth-promoting effects of the circulation hormones associated with obesity and insulin resistance, such as leptin.

Methodology/Principal Findings

A two-stage case-control study was used to explore the role of polymorphisms of Leptin (LEP) and Leptin receptor (LEPR), either alone or in combination with environmental factors in colorectal carcinogenesis. In stage 1, 20 single nucleotide polymorphisms (SNPs) that tag common SNPs in these two genes were genotyped among 470 cases and 458 controls. In stage 2, another population with 314 cases and 355 controls were genotyped for the two most promising SNPs from stage 1. LEPR rs12037879 only presented modestly increased colorectal cancer risk, with odds ratios of 1.41 (95% confidence interval [CI] 1.13–1.76) and 1.74 (95%CI 1.08–2.81) for GA and AA genotype when compared with GG genotype in combined population. Smokers carrying LEPR rs12037879 A allele presented 1.67-fold (95%CI 1.39-fold to 2.01-fold) increased colorectal cancer risk when compared with non-smokers carrying GG genotype in combined analysis. Individuals with family history of cancer harboring LEPR rs12037879 A allele showed 1.52-fold (95%CI: 1.24-fold to 1.86-fold) increased colorectal cancer risk, compared with individuals without family history of cancer harboring GG genotype. Multifactor gene-environment interaction analysis revealed significant interactions among LEPR rs12037879, LEPR rs6690625, smoking status and family history of cancer, exhibiting a gradient of increased colorectal cancer risk along with the increasing number of risk factors (P = 9.82×10⁻¹⁰).

Conclusions/Significance

Our research supports that polymorphisms in LEPR may be associated with marginal increase in the risk for colorectal cancer. Moreover, this association could be strengthened by cigarette smoking and family history of cancer.     

Identification and evaluation of reference genes for quantitative real-time PCR analysis in Passiflora edulis under stem rot condition

Molecular Biology Reports - Passion fruit (Passiflora edulis), an important tropical and subtropical fruit, has a high edible and medicinal value. Stem rot disease is one of the most important...     

Liver size and lipid content differences between BALB/c and BALB/cJ mice on a high-fat diet are due,in part,to Zhx2

Mammalian Genome - BALB/cJ mice exhibit considerable phenotypic differences with other BALB/c substrains. Some of these traits involve the liver, including persistent postnatal expression of genes...     

Potential of intestinal electrical stimulation for obesity: a preliminary canine study

Objective: The aims of this study were to investigate the therapeutic potential of intestinal electrical stimulation (IES) for obesity. Experiments were performed to investigate the effects of IES on food intake, gastric tone, gastric accommodation, and its possible pathway. Research Methods and Procedures: Ten normal dogs and six dogs with truncal vagotomy were used in this study. Each dog was equipped with a gastric cannula for the measurement of gastric tone and accommodation by barostat and one pair of duodenal serosal electrodes for IES. The experiment on food intake was composed of both control session without IES and IES session after a 28‐hour fast. The experiment on gastric tone and accommodation was performed in the fasting and fed states and composed of three sessions: control, IES, and IES with N^G‐nitro‐l ‐arginine. Results: IES significantly reduced food intake in the normal dogs (459.0 vs. 312.6 grams, p < 0.001). The food intake was negatively correlated with the fasting gastric volume during IES. IES significantly decreased fasting gastric tone in the normal dogs reflected as a decrease in gastric volume (89.1 vs. 261.3 mL, p < 0.01), which was abolished by vagotomy and N^G‐nitro‐l ‐arginine. Discussion: IES reduces food intake and inhibits gastric tone in the fasting state. The inhibitory effect of IES on gastric tone is mediated by both vagal and nitrergic pathway.     

Mapping of qGL7-2,a grain length QTL on chromosome 7 of rice

A residual heterozygous line(RHL)carrying a heterozygous segment between two SSR loci RM11 and RM134 on the rice chromosome 7 was selected from a set of recombinant inbred lines from the cross D50(javanica)/HB277(indica).The former parent produces much longer grains than the latter.Selfed progenies of this selection were analyzed genotypically(SSRs)and phenotypically(grain length).Grain length was discontinuously variable in the mapping populations,allowing for the placement of this QTL qGL7-2 within a～4.8 cM interval defined by RM351 and RM234.A set of new markers within this region were developed,which narrowed the QTL to a 278 kb region defined by the markers Indel1 and RM21945.This region contains 49 predicted genes.The results also suggest that the novel allele for grain length will be used for the application of marker assisted selection for the improvement of grain length.     

Inhibitory effects of intestinal electrical stimulation on food intake, weight loss and gastric emptying in rats

The aim was to investigate the effects of intestinal electrical stimulation (IES) on food intake, body weight, and gastric emptying in rats. An experiment on food intake and weight change was performed in 22 rats on a control diet and 10 diet-induced obese (DIO) rats for 4 wk with IES or sham IES. The effect of IES on gastric emptying was performed in another 20 rats in the control group. We found that 1) in control rats, 4-wk IES resulted in a reduction of 18.2% in the total amount of food intake compared with sham-IES (P = 0.02); the rats treated with IES had a weight change of -1 +/- 7.8g (P = 0.03), which was equivalent to a weight loss of 6.2% due to IES when adjusted for normal growing. 2) Acute IES delayed gastric emptying by 20% in the control rats (P < 0.01). 3) In the DIO rats, 1-wk IES with the same parameters as those used in the control rats resulted in a significant reduction in the total amount of food intake (126.6 +/- 6.3 g vs. 116.9 +/- 3.2 g, P < 0.01). More reduction in food intake was noted, and a significant weight change was also observed when stimulation energy was increased. 4) No adverse events were observed in any of the experiments. In conclusion, IES delays gastric emptying, reduces food intake, and decreases weight gain in control growing rats. These data suggest that it is worthy to explore therapeutic potentials of IES for obesity.     

外来入侵植物的氮代谢及其土壤氮特征

研究了4种外来入侵植物(五爪金龙、南美蟛蜞菊、金腰箭和马缨丹)和1种本地植物鸡矢藤(对照)的氮代谢及其土壤氮特征.结果表明:外来人侵植物的组织硝酸还原酶活性、根际土壤NH4-N、NO3-N含量、蛋白酶活性和脲酶活性均较高,分别为鸡矢藤的1.65～4.34、1.56～2.15、1.72～3.11、1.43～3.23和1.41～3.33倍,而植物组织硝态氮含量则较低,仅为鸡矢藤的17.5%～50.6%.相关分析表明:植物组织硝酸还原酶活性与根际土壤总氮、NH4-N、NO3-N含量呈显著正相关(P<0.05),与蛋白酶活性和脲酶活性呈极显著正相关(P<0.01).这说明,外来植物入侵使土壤氮代谢加快,氮的生物有效性增强,氮同化能力提高,并且较好地将植物体氮素代谢与土壤氮素代谢协调起来.因此,较强的氮素同化能力与加速土壤氮素的转化可能是植物成功入侵的重要机制之一.