The Complete Mitochondrial Genome Sequence of the Hornwort <Emphasis Type="Italic">Megaceros</Emphasis><Emphasis Type="Italic">aenigmaticus</Emphasis> Shows a Mixed Mode of Conservative Yet Dynamic Evolution in Early Land Plant Mitochondrial Genomes

Land plants possess some of the most unusual mitochondrial genomes among eukaryotes. However, in early land plants these genomes resemble those of green and red algae or early eukaryotes. The question of when during land plant evolution the dramatic change in mtDNAs occurred remains unanswered. Here we report the first completely sequenced mitochondrial genome of the hornwort, Megaceros aenigmaticus, a member of the sister group of vascular plants. It is a circular molecule of 184,908 base pairs, with 32 protein genes, 3 rRNA genes, 17 tRNA genes, and 30 group II introns. The genome contains many genes arranged in the same order as in those of a liverwort, a moss, several green and red algae, and Reclinomonas americana, an early-branching eukaryote with the most ancestral form of mtDNA. In particular, the gene order between mtDNAs of the hornwort and Physcomitrella patens (moss) differs by only 8 inversions and translocations. However, the hornwort mtDNA possesses 4 derived features relative to green alga mtDNAs—increased genome size, RNA editing, intron gains, and gene losses—which were all likely acquired during the origin and early evolution of land plants. Overall, this genome and those of other 2 bryophytes show that mitochondrial genomes in early land plants, unlike their seed plant counterparts, exhibit a mixed mode of conservative yet dynamic evolution. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Libo Li and Bin Wang contributed equally to this work.     

Reduction of Root-Knot Nematode, Meloidogyne javanica, and Ozone Mass Transfer in Soil Treated with Ozone

Ozone gas (O(3)) is a reactive oxidizing agent with biocidal properties. Because of the current phasing out of methyl bromide, investigations on the use of ozone gas as a soil-fumigant were conducted. Ozone gas was produced at a concentration of 1% in air by a conventional electrical discharge O(3) generator. Two O(3) dosages and three gas flow rates were tested on a sandy loam soil collected from a tomato field that had a resident population of root knot nematodes, Meloidogyne javanica. At dosages equivalent to 50 and 250 kg of O(3)/ha, M. javanica were reduced by 24% and 68%, and free-living nematodes by 19% and 52%, respectively. The reduction for both M. javanica and free-living nematodes was dosage dependent and flow rate independent. The rates of O(3) mass transfer (OMT) through three soils of different texture were greater at low and high moisture levels than at intermediate ones. At any one soil moisture level, the OMT rate varied with soil texture and soil organic matter content. Results suggest that soil texture, moisture, and organic matter content should be considered in determining O(3) dosage needed for effective nematode control.     

The Choice of Translation Initiation Site of the Rep Proteins from Goose Parvovirus P9-Generated mRNA Is Governed by Splicing and the Nature of the Excised Intron

The goose parvovirus (GPV) Rep 1 and Rep 2 proteins are encoded by P9-generated mRNAs that are either unspliced or spliced within the rep gene region, respectively. These mRNAs are present in an approximately equal ratio. The translation of Rep 1 was initiated from the first AUG in unspliced P9-generated mRNA; however, this AUG was bypassed in spliced P9-generated RNA and Rep 2 translation initiated predominately at the next initiating AUG downstream. We show that the choice of the site of initiation of translation of GPV Rep-encoding mRNAs is governed both by the splicing process itself and by the nature of the excised intron.Goose parvovirus (GPV) has identical hairpin termini, is most similar in both nucleotide sequence and protein homology to adeno-associated virus 2 (AAV2), and has been classified as a member of the Dependovirus genus (10-12); however, unlike the AAVs, GPV can replicate efficiently without the aid of a helper virus (12). The RNA expression profile of GPV is a surprising hybrid of features of the Parvovirus and Dependovirus genera of the Parvovirinae (7). Similar to the Dependovirus AAV5, RNAs transcribed from the GPV upstream P9 promoter, which encode the viral Rep protein(s), are polyadenylated at high efficiency at a polyadenylation [(pA)p] site located within the small intron in the center of the genome (7). No promoter analogous to the Dependovirus P19 promoter has been detected; however, similar to minute virus of mice (MVM) and other members of the Parvovirus genus, approximately half of the pre-mRNAs generated from the P9 promoter are additionally spliced within the putative GPV Rep coding region between a donor site located at nucleotide (nt) 814 and an acceptor site at nt 1198 (7). The GPV RNA profile has been shown to be the same in both human 293T and goose CGBQ cells (7). Thus, the mechanism that GPV uses for the expression of its nonstructural gene is more like that used by members of the autonomous Parvovirus group.In this report, we describe the coding strategy for the nonstructural proteins of GPV. We demonstrate that the large Rep 1 protein is encoded uninterruptedly in open reading frame 1 (ORF 1) from the unspliced P9-generated mRNA using an initiating AUG codon at nt 537. The smaller Rep 2 protein is encoded by the spliced P9-generated mRNA; it initiates in ORF 2 at an AUG at nt 650 and continues in ORF 1 after the splice. Strikingly, the first upstream AUG at nt 537 is not utilized in spliced P9-generated mRNA. We show that the choice of initiation site is governed by the splicing process itself and by the nature of the excised intron.     

Kinematics Modeling and Experiments of Pectoral Oscillation Propulsion Robotic Fish

A robotic fish driven by oscillating fins, "Cownose Ray-I", is developed, which is in dorsoventrally flattened shape withouta tail. The robotic fish is composed of a body and two lateral fins. A three-factor kinematic model is established and used in thedesign of a mechanism. By controlling the three kinematic parameters, the robotic fish can accelerate and maneuver. Forwardvelocity is dependent on the largest amplitude and the number of waves in the fins, while the relative contribution of fin beatfrequency to the forward velocity of the robotic fish is different from the usual result. On the other hand, experimental results onmaneuvering show that phase difference has a stronger effect on swerving than the largest amplitude to some extent. In addition,as propulsion waves pass from the trailing edge to the leading edge, the robotic fish attains a backward velocity of 0. 15 m·s^-1.     

疏肝化瘀通络法对初诊2型糖尿病患者血糖及胰岛β细胞功能的影响

目的:观察中医疏肝化瘀通络法治疗初诊2型糖尿病患者的胰岛β细胞及胰岛素抵抗的影响.方法:将60例符合入选标准的新诊断的2型糖尿病患者,随机分组2组(治疗组与对照组),2组在饮食控制和运动治疗方案的基础上,对照组给予口服二甲双胍片;治疗组在口服二甲双胍的基础上加服以疏肝化瘀通络法组方的中药方剂,两组治疗疗程均为12周.观察治疗前后患者血糖、糖化血红蛋白、胰岛素敏感性及胰岛β细胞功能的影响并记录低血糖及其它不良反应.结果:与治疗前相比,二甲双胍+疏肝化瘀通络方治疗后患者空腹、餐后2 h血糖均下降(P＜0.05);HbA1C下降(P＜0.05);体重指数(BMI)下降(P＜0.05);胰岛素敏感性增加;未观察到低血糖或其它不良反应.结论:疏肝化瘀通络法对初诊2型糖尿病患者有良好的临床疗效.可望为2型糖尿病的中西治疗提供新方法,值得进一步深入研究.     

小梨竹核型分析

一定的参考.