Dual targeting of Myxococcus xanthus protoporphyrinogen oxidase into chloroplasts and mitochondria and high level oxyfluorfen resistance

Much attention has been paid to the signal sequences of eukaryotic protoporphyrinogen oxidases (protoxes); both the organelles targeted by protoxes and the role of protoxes in conferring resistance against protox‐inhibiting herbicides, such as oxyfluorfen, have been examined. However, there have been no reports on the translocation of prokaryotic protoxes. This study investigated the targeting ability of Myxococcus xanthus protox in vitro and in vivo. In an in vitro translocation assay using a dual import system, M. xanthus protein was detected in chloroplasts and mitochondria, suggesting that the M. xanthus protox protein was targeted into both organelles. In order to confirm the in vitro dual targeting ability of M. xanthus, we used a stable transgenic strategy to investigate dual targeting in vivo. In transgenic rice plants overexpressing M. xanthus protox, M. xanthus protox antibody cross‐reacted with proteins with predicted molecular masses of 50 kDa from both chloroplasts and mitochondria, and this in vivo transgene expression corresponded to a prominent increase in chloroplastic and mitochondrial protox activity. Seeds from the transgenic lines M4 and M7 germinated in solid Murashige and Skoog media of up to 500 µm of oxyfluorfen, whereas wild‐type seeds did not germinate in 1 µm . After 4‐week‐old‐rice plants were treated with oxyfluorfen for 3 d, lines M4 and M7 exhibited normal growth, whereas the wild‐type line was severely bleached and necrotized. The herbicidal resistance is attributed to the insignificant accumulation of photodynamic protoporphyrin IX in cytosol because the high chloroplastic and mitochondrial protox activity in oxyfluorfen‐treated transgenic lines, compared with that in oxyfluorfen‐treated and untreated wild‐type plants, metabolizes protoporphyrinogen IX to chlorophyll and heme. A practical application of the dual targeting of M. xanthus protox for obtaining outstanding resistance to peroxidizing herbicides is discussed.     

Double intratibial injection of human tonsil-derived mesenchymal stromal cells recovers postmenopausal osteoporotic bone mass

Background and aims

Osteoporosis, which is a disease characterized by weakening of the bone, affects a large portion of the senior population. The current therapeutic options for osteoporosis have side effects, and there is no effective treatment for severe osteoporosis. Thus, we urgently need new treatment strategies, such as topical therapies and/or safe and effective stem cell therapies.

Mercury‐associated DNA hypomethylation in polar bear brains via the LUminometric Methylation Assay: a sensitive method to study epigenetics in wildlife

In this paper we describe a novel approach that may shed light on the genomic DNA methylation of organisms with non‐resolved genomes. The LUminometric Methylation Assay (LUMA) is permissive for genomic DNA methylation studies of any genome as it relies on the use of methyl‐sensitive and ‐insensitive restriction enzymes followed by polymerase extension via Pyrosequencing technology. Here, LUMA was used to characterize genomic DNA methylation in the lower brain stem region from 47 polar bears subsistence hunted in central East Greenland between 1999 and 2001. In these samples, average genomic DNA methylation was 57.9% ± 6.69 (SD; range was 42.0 to 72.4%). When genomic DNA methylation was related to brain mercury (Hg) exposure levels, an inverse association was seen between these two variables for the entire study population (P for trend = 0.17). After dichotomizing animals by gender and controlling for age, a negative trend was seen amongst male animals (P for trend = 0.07) but no associations were found in female bears. Such sexually dimorphic responses have been found in other toxicological studies. Our results show that genomic DNA methylation can be quantitatively studied in a highly reproducible manner in tissue samples from a wild organism with a non‐resolved genome. As such, LUMA holds great promise as a novel method to explore consequential questions across the ecological sciences that may require an epigenetic understanding.     

Gene therapy for pathological scar with hepatocyte growth factor mediated by recombinant adenovirus vector

Pathologic scar, characterized by excessive dermal fibrosis and scarring, is a common im-portant clinical sequela after wound healing. It often appears during wound healing after deep burn, surgical cutting and other injured skin. Accumulation of extracellular matrix (ECM) proteins is a manifestation of increased collagen synthesis and/or reduced matrix degradation, resulting in excessive scarring with a deformed appearance and dysfunction[1]. To date, treatment modalities to scar include sur…     

纤维素在不同介质中的吸附碱的研究

文中研究了纤维素在不同介质(水、乙醇、吡啶及N,N-二甲基乙酰胺)中吸附碱测定情况并通过对比总结出了纤维素对氢氧化钠随用碱量及介质变化规律:纤维素的吸附碱量随着介质及用碱量不同而有所变化,用水作碱化介质比用有机溶剂/水作碱化介质时的吸附碱量少;在用有机溶剂/水作碱化介质时,纤维素对碱吸附表现出大致相同的变化趋势。     

Capacité caulogène de cellules de cal issues des couches cellulaires minces de type épidermique de ramifications florales de Nicotiana tabacum cv. Wise. 38 Par

Bud formation capacity of callus formed from thin epidermal cell loyers excised from floral branches of Nicotiana tabacum cv. Wise. 38. Subepidermal cells of thin tissue pieces with a few cell layers were capable of forming eitber buds, roots, (lowers or non-organ ogenetic callus. To determine wheiher this calltjs is able to dirferentiate into organs, we transferred it to media inducing eitber flowers, or buds, or roots. In this paper, we study ibe capacity of lbe callus to form buds. In 50% of the cases, the explants (being maintained for I day to 2 years in callus media) can still express the capacity to form buds. This percentage increased with increased agar concentration of the culture media. At the histological level, non-organogenetic callus is characterized by the absence of tracheid differentiation, whereas in the organogenetic callus, iracheids were induced after their transfer into a ‘Bud medium’ and indicate an organogenetic differentiation pattern.     

Short pulse of 1080 improves the survival of brown kiwi chicks in an area subjected to long-term stoat trapping

Many mainland populations of kiwi are declining because stoats (Mustela erminea) kill most of their chicks. Stoats are often trapped during conservation programmes, but the long-term effectiveness of trapping has not been measured. During continuous trapping of mammalian predators in the 9800?ha Whangarei Kiwi Sanctuary, the survival of brown kiwi (Apteryx mantelli) chicks declined over time. Following the use of sodium fluoroacetate (1080) to kill rats (Rattus spp.) and possums (Trichosurus vulpecula) and likely secondary poisoning of stoats, chick survival at Riponui increased from 5% to 56%, and the 62% chick survival at Rarewarewa was better than the 20% recorded in a trapped-only area nearby. We suggest that untrappable stoats accumulate in areas subjected to continuous predator trapping. Conservation managers should build into their long-term pest control programmes a periodic pulse of an alternative tool to kill pests that, for whatever reason, actively avoid the primary control tool.     

Metagenomic and geochemical characterization of pockmarked sediments overlaying the Troll petroleum reservoir in the North Sea

ABSTRACT: BACKGROUND: Pockmarks (depressions in the seabed) have been discovered throughout the world's oceans and are often related to hydrocarbon seepage. Although high concentrations of pockmarks are present in the seabed overlaying the Troll oil and gas reservoir in the northern North Sea, geological surveys have not detected hydrocarbon seepage in this area at the present time. In this study we have used metagenomics to characterize the prokaryotic communities inhabiting the surface sediments in the Troll area in relation to geochemical parameters, particularly related to hydrocarbon presence. We also investigated the possibility of increased potential for methane oxidation related to the pockmarks. Five metagenomes from pockmarks and plain seabed sediments were sequenced by pyrosequencing (Roche/454) technology. In addition, two metagenomes from seabed sediments geologically unlikely to be influenced by hydrocarbon seepage (the Oslofjord) were included. The taxonomic distribution and metabolic potential of the metagenomes were analyzed by multivariate analysis and statistical comparisons to reveal variation within and between the two sampling areas. RESULTS: The main difference identified between the two sampling areas was an overabundance of predominantly autotrophic nitrifiers, especially Nitrosopumilus, and oligotrophic marine Gammaproteobacteria in the Troll metagenomes compared to the Oslofjord. Increased potential for degradation of hydrocarbons, especially aromatic hydrocarbons, was detected in two of the Troll samples: one pockmark sample and one from the plain seabed. Although presence of methanotrophic organisms was indicated in all samples, no overabundance in pockmark samples compared to the Oslofjord samples supports no, or only low level, methane seepage in the Troll pockmarks at the present time. CONCLUSIONS: Given the relatively low content of total organic carbon and great depths of hydrocarbon containing sediments in the Troll area, it is possible that at least part of the carbon source available for the predominantly autotrophic nitrifiers thriving in this area originates from sequential prokaryotic degradation and oxidation of hydrocarbons to CO2. By turning CO2 back into organic carbon this subcommunity could play an important environmental role in these dark oligotrophic sediments. The oxidation of ammonia to nitrite and nitrate in this process could further increase the supply of terminal electron acceptors for hydrocarbon degradation.     

科尔沁沙地蒙古族和汉族庭园植物群落垂直结构与种类组成比较——以内蒙古科尔沁左翼后旗为例

在内蒙古通辽市科尔沁左翼后旗蒙古族居住地区采用随机抽样和农户推荐选择30个农户,同时在邻近地区的汉族选择了10个农户作为对比分析。庭园样方取样为整个庭园面积,设立40个样方进行调查。结果表明,内蒙古通辽市科尔沁左翼后旗蒙古族庭园和邻近地区汉族庭园植物垂直结构主要有0~1 m、1~2 m、2~5 m、5~10 m、10 m等五类,其中不论是小规模庭园还是大规模庭园,5 m以下的阶层占优势;两个民族庭园植物种植模式研究结果阐明科尔沁左翼后旗蒙古族与邻近汉族相比,目前很少栽培观赏植物,仍停留在与日常生活相关的蔬菜植物栽培的水平上,而邻近的汉族已开始注重栽培美化环境的庭园植物。此外,本研究运用MVSP统计软件分析庭园类型表明科尔沁左翼后旗蒙古族庭园主要有4种类型,邻近的汉族庭园有3种类型,并且当地蒙古族与邻近的汉族庭园有所差异,这些差异是由两个民族间农耕文化传统以及畜牧业植物文化差异、庭园面积、庭园历史及庭园管理水平、传统植物利用知识的差异所造成。