Metabolic engineering of rice leading to biosynthesis of glycinebetaine and tolerance to salt and cold

Genetically engineered rice (Oryza sativa L.) with the ability to synthesize glycinebetaine was established by introducing the codA gene for choline oxidase from the soil bacterium Arthrobacter globiformis. Levels of glycinebetaine were as high as 1 and 5 micromol per gram fresh weight of leaves in two types of transgenic plant in which choline oxidase was targeted to the chloroplasts (ChlCOD plants) and to the cytosol (CytCOD plants), respectively. Although treatment with 0.15 M NaCl [corrected] inhibited the growth of both wild-type and transgenic plants, the transgenic plants began to grow again at the normal rate after a significantly less time than the wild-type plants after elimination of the salt stress. Inactivation of photosynthesis, used as a measure of cellular damage, indicated that ChlCOD plants were more tolerant than CytCOD plants to photoinhibition under salt stress and low-temperature stress. These results indicated that the subcellular compartmentalization of the biosynthesis of glycinebetaine was a critical element in the efficient enhancement of tolerance to stress in the engineered plants.     

The gain of three mitochondrial introns identifies liverworts as the earliest land plants

The first evidence for the emergence of land plants (embryophytes) consists of mid-Ordovician spore tetrads (approximately 476 Myr old). The identity of the early plants that produced these spores is unclear; they are sometimes claimed to be liverworts, but there are no associated megafossils, and similar spores can be produced by a diversity of plants. Indeed, the earliest unequivocal megafossils of land plants consist of early vascular plants and various plants of uncertain affinity. Different phylogenetic analyses have identified liverworts, hornworts and bryophytes as each being the first lineage of land plants; the consensus of these conflicting topologies yields an unresolved polychotomy at the base of land plants. Here we survey 352 diverse land plants and find that three mitochondrial group II introns are present, with occasional losses, in mosses, hornworts and all major lineages of vascular plants, but are entirely absent from liverworts, green algae and all other eukaryotes. These results indicate that liverworts are the earliest land plants, with the three introns having been acquired in a common ancestor of all other land plants, and have important implications concerning the early stages of plant evolution.     

戈塘卡林型金矿区苔藓植物与维管植物元素相关性研究

利用A Analyst800原子吸收光谱仪和AF-640原子荧光光谱仪（AF-640））对戈塘金矿区的苔藓植物和维管植物进行元素含量测定,应用SPSS统计软件进行相关性分析,发现不同类群植物在卡林型金矿区的元素相关性差异很大,同一类群植物在金矿和煤矿上相关性不同。此结果为探矿植物的研究提供了有力的证据。     

Effects of LaCl3 on the growth and photosynthetic characteristics of Fny-infected tobacco seedlings

Plant growth, gas exchange characteristics, chlorophyll fluorescence, disease index, and disease prevention efficiency of LaCl3 in tobacco (Nicotiana glutinosa) plants infected by Fny-CMV (fny stain of cucumber mosaic virus) strain were determined. Leaf area, chloro-phyll and carotenoid contents, maximum photosynthesis rate, apparent quantum yield, and carboxylation efficiency dramatically decreased after 5 weeks post inoculation. The plants infected by Fny-CMV only presented much severer symptom than those infected in the presence of appropriate concentration of LaCl3. ETR (apparent rate of photosynthetic electron transport), NPQ (nonphotochemical quenching), qP (coef-ficient of photochemical quenching), and yield (II) in infected tobacco plants obviously reduced in higher light intensity after 5 weeks post inoculation. And these fluorescence parameters in Fny-infected plants obviously reduced compared with those in the plants infected by Fny in the presence of LaCl3. Together with the growth status and disease index, it revealed that exogenously appropriate concentration of LaCl3 could significantly alleviate the damage of tobacco seedlings caused by Fny-CMV.     

Efficacy of a self-management program for childhood asthma--a prospective controlled study

Individual plants of Sorghum bicolor mature different adaptive reactions to salinity. The positive correlation between the frequency of specific reactions and the tolerance level of plants with that specific reaction results from adaptive determinism (AD). The effect of complexity in environmental conditions on AD in plants adapting for the first time to salinity, A0, and in their offspring A1 was compared. Environmental complexity increases when uncontrolled factors besides salinity affect plants. The diversity of reactions of plants correlates positively with environmental complexity. AD correlates negatively to environmental complexity in A1. In contrast, environmental complexity has no effect on AD in A0. A1 are more tolerant to salinity than A0: A1 inherited adaptive information. The likelihood that A1 plants are exposed to the same uncontrolled factor as their parent is low, and so the decrease of AD in A1 due to environmental complexity suggests that: (1) the information inherited is specific to saline conditions; (2) AD results mainly from inherited pre-existing information; plants react as informatively closed systems: saline conditions trigger the expression of an adaptive, pre-existing program. For A0, conclusions are: (1) the adaptive reaction is not an expression of pre-existing information; (2) AD emerges during the adaptation process: the environment imprints adaptively the plant's development. In this case, plants react as open systems in terms of information.     

The state-of-the-art of steel technology used for chinese power plants and its future

The development and construction of Ultra Super Critical(USC) fossil fired power plants and advanced nuclear power plants are the most important and effective issue to improve national electricity structure in China and to fulfill the national emission aim which had been proposed and promised.Further, steel technology is one of the most imperative fundamentals to ensure the development and construction of USC fossil fired power plants and advanced nuclear power plants.This paper briefly introduced the state-of-the -art and achievement of steel technology used for USC fossil fired power plants and advanced nuclear power plants in China so far.Meanwhile,the authors also analyzed and discussed the potential research and development plans of the important steel technology in China in the near future.     

Frequent occurrence of transgene deletion in transgenic plants

The status of the transgene in tobacco plants transformed by Agrobacterium was analyzed with PCR. Twelve percent of the transgenic plants with the nptII gene showed different levels of transgene deletion, which was also found in transgenic watermelon (10-30%) and carrot (40-60%). It appeared that the percentage of transgenic plants carrying deleted transgenes depended on both the transgene and the plant. It is suggested that the transgene should be inserted between a right border and a selection marker to reduce the number of transgenic plants containing deleted transgenes after selection.     

中国电站用钢技术现状和未来发展

 超超临界火电机组和百万千瓦核电机组建设是我国优化电源结构和实现国家节能减排战略目标的最重要措施。钢铁材料技术是保证超超临界火电机组和百万千瓦核电机组建设顺利进行的最重要基础之一。本文介绍了迄今我国在超超临界火电机组和百万千瓦核电机组用钢方面的研发进展和取得的成就,并与国外同类技术的研发水平进行了对比。同时,本文也分析和讨论了我国超超临界火电机组和百万千瓦核电机组用钢技术的未来发展问题。     

Comparison of Enzyme Activities in Vegetated and Nonvegetated Sediments

This study focuses on the effect of aquatic plants on the changes of enzyme activities in wetland sediments. Wetland plants play essential roles both as a carbon supplier for microbes which synthesize enzymes and as a regulator for enzyme activity by modifying hydrochemistry in the rhizosphere. Although numerous studies have been carried out on soil enzymes, little information is available on the vertical distribution and temporal variation of enzyme activities affected by the presence of plants in wetlands. Our results clearly show that sediments with wetland plants exhibit significantly higher enzyme activities of β-glucosidase, arylsulfatase, phosphatase, and N-acetylglucosaminidase (P<0.05) up to a depth of 15?cm throughout the year, whereas only lower values were observed even at the surface of sediments (0–3?cm) without plants. However, in the field, there were no statistically significant changes of enzyme activities associated with the changes of season and the vertical position along the depth (P<0.05). This indicates that the organic carbon supplemented by root exudates, root debris, and plant residue played an important role in increasing enzyme activities in the sediments with plants. The mechanisms driven by aquatic plants such as oxygen diffusion and transpiration-induced advection did not induce the short-term changes in enzyme activities. Exceptionally, the changes of sulfate availability and the increase of temperature have implications in the changes of arylsulfatase activities depending on the location (vegetated versus nonvegetated sediment) (P = 0.000), season (growing season versus senescence) (P = 0.042), and sediment depth (P = 0.002). Since wetlands treat wastewaters with variable carbon sources, it would be beneficial to maintain increased enzyme activities in the regeneration of inorganic nutrients from organic materials. In addition, the presence of plants would vertically extend the area where the higher enzyme activities are observed and the movement of wastewater takes place and, consequently, could accelerate wetland treatment efficiency.     

Screening for in vitro anti-tumor-promoting activities of edible plants from Indonesia

A total of 135 methanol extracts from 48 plant families (107 species) of edible Indonesian plants were screened for their in vitro anti-tumor-promoting activities using the tumor promoter 12-O-hexadecanoylphorbol-13-acetate (HPA)induced Epstein-Barr virus (EBV) activation test in Raji cells. Examined at a concentration of 200 mg/ml, 71% of the extracts inhibited EBV activation by 30% or more. The rate is comparable to the rate observed in our previous tests of edible Thai (60%) plants and much higher than the rate (26%) observed with Japanese plants. In particular, the plant families Zingiberaceae (13/13 active) and Umbelliferae (7/8 active) are suggested to be desirable sources of effective cancer-preventive agents because of the strikingly high frequency of inhibitory activity. Thus, a high potential of edible Southeast Asian plants for cancer chemoprevention is indicated.     

Critical care nutrition: routes of feeding

The experiments were carried out with maize (Zea mays L.) seedlings, hybrid Kneja 530, grown hydroponically in a growth chamber. Twelve-day-old plants were foliar treated with putrescine, N1-(2-chloro-4-pyridyl)-N2-phenylurea (4-PU-30), and abscisic acid (ABA) at concentrations of 10(-5) m. Twenty-four hours later the plants were subjected to a water deficit program, induced by 15% polyethylene glycol (PEG; molecular weight, 6,000). Three days after drought stress half of the plants were transferred to nutrient solution for the next 3 days. The effects of the water shortage, rewatering, and plant growth regulator (PGR) treatment on the fresh and dry weights, leaf pigment content, proline level, relative water content (RWC), transpiration rate, activities of catalase and guaiacol peroxidase, hydrogen peroxide content, and level of the products of lipid peroxidation were studied. It was established that the application of PGRs alleviated to some extent the plant damage provoked by PEG stress. At the end of the water shortage program the plants treated with these PGRs possessed higher fresh weight than drought-subjected control seedlings. It was found also that putrescine increased the dry weight of plants. Under drought, the RWC and transpiration rate of seedlings declined, but PGR treatment reduced these effects. The accumulation of free proline, malondialdehyde, and hydrogen peroxide was prevented in PGR-treated plants compared with the water stress control. The results provided further information about the influence of putrescine, 4-PU-30, and ABA on maize plants grown under normal, drought, and rewatering conditions. Key Words. Maize-Putrescine-4-PU-30-ABA-Drought     

Distinct functions of capsid protein in assembly and movement of tobacco etch potyvirus in plants

Tobacco etch potyvirus engineered to express the reporter protein beta-glucuronidase (TEV-GUS) was used for direct observation and quantitation of virus translocation in plants. Four TEV-GUS mutants were generated containing capsid proteins (CPs) with single amino acid substitutions (R154D and D198R), a double substitution (DR), or a deletion of part of the N-terminal domain (delta N). Each modified virus replicated as well as the parental virus in protoplasts, but was defective in cell-to-cell movement through inoculated leaves. The R154D, D198R and DR mutants were restricted essentially to single, initially infected cells. The delta N variant exhibited slow cell-to-cell movement in inoculated leaves, but was unable to move systemically due to a lack of entry into or replication in vascular-associated cells. Both cell-to-cell and systemic movement defects of each mutant were rescued in transgenic plants expressing wild-type TEV CP. Cell-to-cell movement, but not systemic movement, of the DR mutant was rescued partially in transgenic plants expressing TEV CP lacking the C-terminal domain, and in plants expressing CP from the heterologous potyvirus, potato virus Y. Despite comparable levels of accumulation of parental virus and each mutant in symptomatic tissue of TEV CP-expressing transgenic plants, virions were detected only in parental virus- and delta N mutant-infected plants, as revealed using three independent assays. These data suggest that the potyvirus CP possesses distinct, separable activities required for virion assembly, cell-to-cell movement and long-distance transport.     

Transgenic plants expressing potato virus X ORF2 protein (p24) are resistant to tobacco mosaic virus and Ob tobamoviruses

The p24 protein, one of the three proteins implicated in local movement of potato virus X (PVX), was expressed in transgenic tobacco plants (Nicotiana tabacum Xanthi D8 NN). Plants with the highest level of p24 accumulation exhibited a stunted and slightly chlorotic phenotype. These transgenic plants facilitate the cell-to-cell movement of a mutant of PVX that contained a frameshift mutation in p24. Upon inoculation with tobacco mosaic virus (TMV), the size of necrotic local lesions was significantly smaller in p24+ plants than in nontransgenic, control plants. Systemic resistance to tobamoviruses was also evidenced after inoculation of p24+ plants with Ob, a virus that evades the hypersensitive response provided by the N gene. In the latter case, no systemic symptoms were observed, and virus accumulation remained low or undetectable by Western immunoblot analysis and back-inoculation assays. In contrast, no differences were observed in virus accumulation after inoculation with PVX, although more severe symptoms were evident on p24-expressing plants than on control plants. Similarly, infection assays conducted with potato virus Y showed no differences between control and transgenic plants. On the other hand, a considerable delay in virus accumulation and symptom development was observed when transgenic tobacco plants containing the movement protein (MP) of TMV were inoculated with PVX. Finally, a movement defective mutant of TMV was inoculated on p24+ plants or in mixed infections with PVX on nontransgenic plants. Both types of assays failed to produce TMV infections, implying that TMV MP is not interchangeable with the PVX MPs.     

A review of fractionations of rare earth elements in plants

Studies were carried out on several aspects of rare earth elements （REEs）, such as the theory and practice of their applications in agriculture, their geochemical behaviors in natural and agricultural ecosystems, the mechanisms for the increase of crop yield using REE fertilizer, and their toxicology. However, limited knowledge was available for the transfer processes and the features and mechanisms of distribution and fractionations of REEs inside plants. The characteristics of REE fractionations in plants can be used to ＂trace＂ the pathway of REE transportation from soils （solution） to plants. A better understanding of the mechanisms of REE fractionations was helpful to investigate the controlling factors, including both the internal and the external ones. The characteristics and mechanisms of REE fractionations in plants and their significance were reviewed. Furthermore, the prospect for these fields was discussed, in hope of providing a new way in studying the bioavailability of REEs and heavy metals.     

Bcl-2 inhibits cell death of serum-free mouse embryo cells caused by epidermal growth factor deprivation

China has accumulated a rich body of empirical knowledge of the use of medicinal plants for the treatment of various diseases throughout its long history. Chemical studies on Chinese medicinal plants provide a valuable material base for the discovery and development of new drugs of natural origin. In this article recent chemical work on various Chinese medicinal plants is reviewed, including Mussaenda pubescens (Rubiaceae), Isatis indigotica (Cruciferae), Euphorbia fischeriana, and E. ebracteolata (Euphorbiaceae), and Stemona species (Stemonaceae). The structural diversity of the medicinal chemical constituents of the above plants is discussed.     

Organ-specific and Agamous-regulated expression and glycosylation of a pollen tube growth-promoting protein

Transmitting tissue-specific (TTS) protein is a pollen tube growth-promoting and attracting glycoprotein located in the stylar transmitting tissue extracellular matrix of the pistil of tobacco. The TTS protein backbones have a deduced molecular mass of about 28 kDa, whereas the glycosylated stylar TTS proteins have apparent molecular masses ranging between 50 and 100 kDa. TTS mRNAs and proteins are ectopically produced in transgenic tobacco plants that express either a cauliflower mosaic virus (CaMV) 35S promoter-TTS2 transgene or a CaMV 35S-promoter-NAG1 (NAG1 = Nicotiana tabacum Agamous gene) transgene. However, the patterns of TTS mRNA and protein accumulation and the quality of the TTS proteins produced are different in these two types of transgenic plants. In 35S-TTS transgenic plants, TTS mRNAs and proteins accumulate constitutively in vegetative and floral tissues. However, the ectopically expressed TTS proteins in these transgenic plants accumulate as underglycosylated protein species with apparent molecular masses between 30 and 50 kDa. This indicates that the capacity to produce highly glycosylated TTS proteins is restricted to the stylar transmitting tissue. In 35S-NAG transgenic plants, NAG1 mRNAs accumulate constitutively in vegetative and floral tissues, and TTS mRNAs are induced in the sepals of these plants. Moreover, highly glycosylated TTS proteins in the 50- to 100-kDa molecular mass range accumulate in the sepals of these transgenic, 35S-NAG plants. These results show that the tobacco NAGI gene, together with other yet unidentified regulatory factors, control the expression of TTS genes and the cellular capacity to glycosylate TTS proteins, which are normally expressed very late in the pistil developmental pathway and function in the final stage of floral development. The sepals in the transgenic 35S-NAG plants also support efficient pollen germination and tube growth, similar to what normally occurs in the pistil, and this ability correlates with the accumulation of the highest levels of the 50- to 100-kDa glycosylated TTS proteins.     

Differential regulation of trichome formation on the adaxial and abaxial leaf surfaces by gibberellins and photoperiod in Arabidopsis thaliana (L.) Heynh

In wild-type (WT) Columbia and Landsberg erecta ecotypes of Arabidopsis thaliana (L.) Heynh., trichomes are present on the adaxial surfaces of all rosette leaves but are absent from the abaxial surfaces of the first-formed leaves. We have determined that both long-day (LD) photoperiod and gibberellin (GA) stimulate trichome formation. WT plants grown in LD conditions produce the first abaxial trichome on earlier leaves than plants grown in short-day (SD) conditions. Photoperiod sensitivity of abaxial trichome formation on WT plants develops gradually over time, reaching the maximum sensitivity about 24 d after germination. Application of gibberellic acid to WT plants growing in SD conditions accelerates the onset of abaxial trichomes. Conversely, application of 20 to 80 mg L-1 paclobutrazol, a GA biosynthesis inhibitor, to wild-type plants suppresses trichome initiation on the abaxial epidermis. The GA-deficient mutants ga1-5 and ga4-1 and the GA-insensitive mutant gai-1 exhibit delayed onset of abaxial trichomes when grown in LD conditions. The null mutant ga1-3 produces completely glabrous leaves when grown in SD conditions. Application of gibberellic acid to glabrous ga1-3 plants consistently induces earlier formation of trichomes on the adaxial epidermis than on the abaxial epidermis, demonstrating a difference between the adaxial and abaxial surfaces in their response to GA with regard to trichome formation.