甘蓝型油菜中脯氨酸积累的分子调控机制

　　渗透胁迫下植物中游离脯氨酸的积累被普遍认为对植物有保护作用。本文对甘蓝型油菜（Brassica napus）中的脯氨酸积累及其调控机理进行了研究。正常生长条件下幼苗叶中脯氨酸含量最高，根中脯氨酸含量最低，盐胁迫后不同部位脯氨酸积累程度相近。盐浓度200 mM起，幼苗开始有明显脯氨酸积累,并随着浓度的增加而增加。PEG处理后脯氨酸积累要明显高于ABA和盐胁迫处理后脯氨酸积累。在成株中，生殖器官中脯氨酸含量明显高于营养器官中脯氨酸含量。 　　我们克隆了编码Δ1-二氢吡咯啉-5-羧酸合成酶（P5CS）,鸟氨酸转氨酶(OAT)和脯氨酸脱氢酶(PDH)的四个基因的cDNA。通过Southern杂交检测P5CS基因在甘蓝型油菜及其亲本白菜型油菜和甘蓝中的拷贝数，发现杂交条带在4倍体油菜中并没有显著的多于其两个2倍体亲本，推测有可能是在物种进化的过程中发生了基因丢失。 　　利用实时定量PCR的方法检测了渗透胁迫下甘蓝型油菜中BnP5CS，BnOAT和BnPDH等基因的表达水平。在ABA处理，盐处理和干旱处理时，BnP5CS1和BnP5CS2的表达在脯氨酸积累开始前就开始有明显上调，但是BnP5CS1的上调水平要比BnP5CS2高许多。BnOAT在ABA处理后表达水平没有太大的变化，在盐胁迫后甚至有一点下调，在干旱处理后却表现为一定程度的上调。另一方面，BnPDH的表达在ABA处理，盐胁迫和干旱胁迫后都受到了抑制。在成株不同器官相关基因表达的研究中发现，BnOAT在叶中表达量最高，BnP5CS和BnPDH在花蕾和花中的表达水平都比其他器官中要高。 　　我们的结果说明，渗透胁迫下甘蓝型油菜中的脯氨酸积累是脯氨酸合成途径的诱导和脯氨酸降解途径的抑制共同作用的结果。在轻度的渗透胁迫下，谷氨酸合成途径占主导地位，而在较为严重的渗透胁迫后期，谷氨酸合成途径和鸟氨酸合成途径共同起作用。甘蓝型油菜生殖器官花和花蕾中脯氨酸的代谢非常旺盛，说明脯氨酸可能在花发育中起着一定的作用。

A normal force distance regulation scheme for near-field optical microscopy

A near-field optical microscope (NFOM) has been developed that combines the features of a near-field optical microscope and an atomic force microscope. Improved control over tip-sample separation has led to improved optical imaging and independent surface topography information. The tip oscillation is normal to the sample plane thereby reducing lateral forces - important for nonperturbative imaging of soft samples. Both topographic images and reflection near-field optical images are presented which demonstrate the capability of the system. © 1996 American Institute of Physics.

MicroRNA regulation and the variability of human cortical gene expression

Understanding the driving forces of gene expression variation within human populations will provide important insights into the molecular basis of human phenotypic variation. In the genome, the gene expression variability differs among genes, and at prese

Suggestive role of eye-stalk of Macrobrachium gangeticum Bate, 1868 in regulation of its reproductive behaviour

Role of eye-stalk of Macrobrachium gangeticum Bate, 1868 in its reproductive behaviour has been examined by conducting deletion and addition experiments. Eye-stalk ablation induced gonadal maturity in both sexes, leading to change in colour and size of ovaries and increase in GSI and oocyte diameter in females and increased length of testes and diameters of seminiferous tubules in males. Injection of eye-stalk extracts tended to at least partly restrict the effects in both sexes. The experiments thus suggested that the eye-stalk of M. gangeticum released some gonad inhibiting factors.

Dynamic regulation of ARGONAUTE4 within multiple nuclear bodies in Arabidopsis thaliana.

DNA methylation directed by 24-nucleotide small RNAs involves the small RNA-binding protein ARGONAUTE4 (AGO4), and it was previously shown that AGO4 localizes to nucleolus-adjacent Cajal bodies, sites of snRNP complex maturation. Here we demonstrate that AGO4 also localizes to a second class of nuclear bodies, called AB-bodies, which are found immediately adjacent to condensed 45S ribosomal DNA (rDNA) sequences. AB-bodies also contain other proteins involved in RNA-directed DNA methylation including NRPD1b (a subunit of the RNA Polymerase IV complex, RNA PolIV), NRPD2 (a second subunit of this complex), and the DNA methyltransferase DRM2. These two classes of AGO4 bodies are structurally independent--disruption of one class does not affect the other--suggesting a dynamic regulation of AGO4 within two distinct nuclear compartments in Arabidopsis. Abolishing Cajal body formation in a coilin mutant reduced overall AGO4 protein levels, and coilin dicer-like3 double mutants showed a small decrease in DNA methylation beyond that seen in dicer-like3 single mutants, suggesting that Cajal bodies are required for a fully functioning DNA methylation system in Arabidopsis.

Mesh regulation in backwater prawn fishing gear

Size grade composition of different species of prawn caught by various back water fishing gear have been enumerated. 57 to 75% of P. indicus captured was less than 10 cm in length. M. dobsoni and M. monoceros captured were less than 10 cm in length. A cod end mesh size of 20-25 mm has been recommended for stake nets for the capture of P. indicus of 10 cm length along with other species.

Evolution of conserved secondary structures and their function in transcriptional regulation networks

Background: Many conserved secondary structures have been identified within conserved elements in the human genome, but only a small fraction of them are known to be functional RNAs. The evolutionary variations of these conserved secondary structures in h

Interaction of corticosterone and nicotine in regulation of prepulse inhibition in mice

The aim of the present Study was to investigate if different levels of circulating corticosterone (CORT) modulate the effect of nicotine on prepulse inhibition (PPI), a measure of sensorimotor gating that is disrupted in schizophrenia and other mental illnesses. Four groups of mice were investigated: sham-operated, adrenalectomized (ADX) and implanted with a cholesterol pellet, ADX and implanted with a 10 mg CORT pellet, or ADX and 50 mg, of CORT. Different CORT levels or doses of nicotine did not significantly affect startle responses. Baseline PPI was significantly reduced in mice implanted with the highest dose of CORT. In ADX mice implanted with cholesterol, nicotine treatment influenced PPI depending on the prepulse intensity. In ADX mice implanted with 50 mg of CORT, treatment with 10 mg/kg of nicotine caused a significant increase in PPI at all prepulse intensities. Binding studies showed that corticosterone treatment had significantly affected nicotinic acetylcholine receptor (nAChR) density in the mouse brain. Treatment with 50 mg CORT decreased I-125-epibatidine binding in the globus pallidus and I-125-alpha-bungarotoxin binding in the claustrum. These results suggest a possible interaction of corticosterone and nicotine at the level of the alpha4- and alpha7-type nAChR in the regulation of PPI. In situations of high circulating levels of corticosterone, nicotine may be beneficial to restore disruption of PPI. (C) 2004 Elsevier Ltd. All rights reserved.

Regulation: A Burden in Biopharmaceutical Industry? The Case of EU-Risk Management Plans

The generation of new medicinal products is both a contributor to global economic growth and a source of valuable benefits to human health. Given their direct responsibility for public health, regulatory authorities monitor closely both the development and exploitation of the underlying technologies and the products derived from them. The manner in which such regulation is implemented can result in regulators constraining or facilitating the generation of new products. This paper will study as an example the impact of EU Risk Management Plans (EU-RMPs), which have been mandatory for the approval of new medicines since 2005, on both the industry and regulatory authorities. In interviews, the responses of those who had experience of the implementation of EU-RMPs were mixed. Although the benefits of a more structured and predictable approach to the evaluation of risk were appreciated, some respondents perceived the regulation as an excessive burden on their organisations. The exploration of factors that influence how EU-RMP regulation affects individual firms provides new insights for both regulators and managers, and demonstrates one aspect of the complexity of the process by which new medicinal products are brought to market.