Chloroplast DNA evidence on the ancient evolutionary split in vascular land plants     

Raubeson LA  Jansen RK 《Science (New York, N.Y.)》1992,255(5052):1697-1699

Two groups of extant plants, lycopsids and psilopsids, alternatively have been suggested to be the living representatives of the earliest diverging lineage in vascular plant evolution. The chloroplast DNA (cpDNA) gene order is known to contain an inversion in bryophytes and tracheophytes relative to one another. Characterization of tracheophyte cpDNAs shows that lycopsids share the gene order with bryophytes, whereas all other vascular plants share the inverted gene order. The distribution of this character provides strong support for the fundamental nature of the phylogenetic separation of lycopsids and marks the ancient evolutionary split in early vascular land plants.  相似文献   

Empowered women, social networks and the contribution of qualitative research: broadening our understanding of underlying causes for food and nutrition insecurity     

Lemke S  Vorster HH  van Rensburg NS  Ziche J 《Public health nutrition》2003,6(8):759-764

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A non-destructive selection method for faster growth at suboptimal temperature in common bean (Phaseolus vulgaris)     

E. Drijfhout  J. C. van Oeveren  R. C. Jansen 《Euphytica》1991,58(1):65-70

Summary A non-destructive method has been developed to select common bean (Phaseolus vulgaris L.) plants whose growth is less effected at a suboptimal temperature. Shoot weight was determined at a suboptimal (14°C) and optimal temperature (20°C), 38 days after sowing and accessions identified with a significantly lower than average weight reduction at 14°C compared to their weight at 20°C. Weight of primary leaves and of the shoot was correlated with seed weight at both temperatures, but no correlation was found between shoot weight reduction at 14°C and seed weight.  相似文献   

The response of cassava cultivars to root-knot nematode infestation: An in vitro method     

Rosan Jansen van Vuuren  Barbara Woodward 《Euphytica》2001,120(1):109-113

The aim of this study was to obtain information on the response of cassava(Manihot esculenta Crantz) to root-knot nematode infestation. To achieve this aim, a novel in vitro dual root/nematode culture method was used, where root cultures of several cassava cultivars were inoculated with axenic Meloidogyne javanica eggs. Following an incubation period,cassava roots were stained, weighed and dissected to determine the number of galls produced on the roots, as well as the number of mature females embedded in the galls. The number of eggs and larvae produced during this time were also determined. Results indicated that the modified in vitro nematode culture medium used was suitable for most root cultures of cassava cultivars. It was found that some cassava cultivars were highly susceptible to root-knot nematode infestation, with some cultivars showing very high numbers of galls and up to 50 mature females inside each gall. Some cassava cultivars screened, however, showed low numbers of galls and mature females, even though the presence of larvae was high. Some of these cultivars formed callus-like structures instead of galls, and this may be a resistance mechanism. This method may be useful as a screening tool, to determine the response and resistance or susceptibility of cassava cultivars to root-knot nematode infestation. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Solanum scabrum—a potential source of a coloring plant extract     

Cornelia Lehmann  Christoph Biela  Stefan Töpfl  Gisela Jansen  Rudolf Vögel 《Euphytica》2007,158(1-2):189-199

The objective of this study was to examine the potential of Solanum scabrum to provide a colorant for food. We conducted a field trial with eight accessions from four different sources and recorded both morphological variability and fruit yield differences between accessions. Further, anthocyanin and glucoalkaloid concentrations were determined. The accessions could be assigned to two distinct groups: a leafy vegetable type with toxic fruits used in Africa and a berry type with edible fruits known as Garden Huckleberry in North America, but both types had edible leaves with low glucoalkaloid concentrations. The leafy vegetable type set not much fruit. In contrast, the berry type yielded on average 800–900 g berries per plant with remarkable high anthocyanin concentrations of 8.1–13.9 g kg⁻¹ fresh weight, calculated as petunidin 3-p-(coumaryl-runtinoside)-5-glucoside. Thus, S. scabrum can serve as a source for natural anthocyanin pigments. In particular, two accessions with a high fruit yield were promising candidates as a berry crop. One had the best anthocyanin concentration of the examined material and the other one had a low percentage of unripe berries as a further advantage.  相似文献   

Genetic differences in growth within and between Lycopersicon species     

Pim Lindhout  Gerard Pet  Ritsert Jansen  Hans Jansen 《Euphytica》1991,57(3):259-265

Summary Growth analyses were carried out on 88 accessions of five Lycopersicon species. Experiments were conducted in a climate room at 19/14° C day/night temperature which was irradiated at 20 W/m² for eight hours per day. Large differences in plant weights between wild species and the cultivated tomato were observed from 44 to 84 days after sowing. The increase in plant dry weight could be described by a second order polynomial function. When compared at a standardized plant weight of one gram, the relative growth rates (RGR) of the wild and cultivated accessions ranged from 5.3 to 11.8% and 8.5 to 12.2% per day respectively, limiting the use of wild species as sources for strong growth. When expressed at plant weights of one and three g large differences in decrease of the RGR were observed within L. esculentum. The modern hybrid tomato cultivars were among the fastest growing genotypes, with a relatively slow decrease in RGR.  相似文献   

ERdj5 is required as a disulfide reductase for degradation of misfolded proteins in the ER     

Ushioda R  Hoseki J  Araki K  Jansen G  Thomas DY  Nagata K 《Science (New York, N.Y.)》2008,321(5888):569-572

Membrane and secretory proteins cotranslationally enter and are folded in the endoplasmic reticulum (ER). Misfolded or unassembled proteins are discarded by a process known as ER-associated degradation (ERAD), which involves their retrotranslocation into the cytosol. ERAD substrates frequently contain disulfide bonds that must be cleaved before their retrotranslocation. Here, we found that an ER-resident protein ERdj5 had a reductase activity, cleaved the disulfide bonds of misfolded proteins, and accelerated ERAD through its physical and functional associations with EDEM (ER degradation-enhancing alpha-mannosidase-like protein) and an ER-resident chaperone BiP. Thus, ERdj5 is a member of a supramolecular ERAD complex that recognizes and unfolds misfolded proteins for their efficient retrotranslocation.  相似文献   

Review and quantitative assessment of ex situ household rainwater harvesting systems in Ethiopia     

Girma Moges  H. Hengsdijk  H.C. Jansen 《Agricultural Water Management》2011,98(8):1215-1227

Ex situ household rainwater harvesting (RWH) systems have been introduced at a large scale in Ethiopia to increase the water availability for smallholders through supplementary irrigation. The first objective of this paper is to review the performance of these systems in Ethiopia based on various assessment studies. The second objective is to provide quantitative biophysical and socio-economic analyses of ex situ household RWH systems contributing to the better understanding of their performance and the identification of options to improve their performance. Uptake of RWH systems by smallholders in Ethiopia is limited and the available information suggests that this is associated among others with poor planning and implementation, poorly functioning input and output markets and the lack of farmers’ skills to use these systems effectively. Our quantitative meta-analyses illustrate that water availability of three studied RWH systems is low in relation to crop water needs, particularly for maize. The variation in area that can be irrigated across years exposes users of RWH systems to considerable risks as the availability of irrigation water depends on prevailing rainfall conditions. The area that can be irrigated varies greatly depending on amount and distribution of rainfall, type of RWH system and crop type. The economics of onion (cash crop) are promising only for plastic lined RWH systems, but those for maize are unfavourable independent of the studied RWH systems. Associated labour requirements especially for water lifting and application are high and possibly constraining the sustainable use of RWH systems. The potential of ex situ household RWH systems to increase agricultural production and income is site-specific depending on biophysical, institutional and socio-economic conditions, and depends on household-specific conditions.  相似文献   

Your practice; what is your diagnosis?     

Jansen M 《Tijdschrift voor diergeneeskunde》2011,136(12):858

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Monitoring and identification of residues of anabolic preparations in slaughtered cattle by HPLC with diode array detection     

E H Jansen  H van Blitterswijk  R W Stephany 《The Veterinary quarterly》1984,6(2):60-65

The new combination of isocratic high performance liquid chromatography (HPLC) with on line UV spectrum detection via a diode array configuration has been applied to the detection and identification of anabolics present in application sites of cattle. Combination of the characteristic retention time in the HPLC chromatogram and a comparison of the full spectrum between 190-400 nm of the anabolic components with that of a standard resulted in a very reliable identification. By means of this method 117 samples of application sites were investigated for the presence of anabolic residues. Of the xenobiotic anabolics , 19-nortestosterone (NT) was found most frequently (in 96 cases), whereas diethylstilbestrol (DES) was found in only 11 cases. In all samples the identification of NT and DES was confirmed by high resolution gas chromatography-mass spectrometry (GCMS).  相似文献