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921.
Chiappetta A Michelotti V Fambrini M Bruno L Salvini M Petrarulo M Azmi A Van Onckelen H Pugliesi C Bitonti MB 《Planta》2006,223(5):917-931
922.
Mantelin S Desbrosses G Larcher M Tranbarger TJ Cleyet-Marel JC Touraine B 《Planta》2006,223(3):591-603
Both root architecture and plant N nutrition are altered by inoculation with the plant growth-promoting rhizobacteria (PGPR)
Phyllobacterium strain STM196. It is known that NO3− and N metabolites can act as regulatory signals on root development and N transporters. In this study, we investigate the
possible interrelated effects on root development and N transport. We show that the inhibition of Arabidopsis lateral root growth by high external NO3− is overridden by Phyllobacterium inoculation. However, the leaf NO3− pool remained unchanged in inoculated plants. By contrast, the Gln root pool was reduced in inoculated plants. Unexpectedly,
NO3− influx and the expression levels of AtNRT1.1 and AtNRT2.1 genes coding for root NO3− transporters were also decreased after 8 days of Phyllobacterium inoculation. Although the mechanisms by which PGPR exert their positive effects remain unknown, our data show that they can
optimize plant development independently from N supply, thus alleviating the regulatory mechanisms that operate in axenic
conditions. In addition, we found that Phyllobacterium sp. elicited a very strong induction of AtNRT2.5 and AtNRT2.6, both genes preferentially expressed in the shoots whose functions are unknown. 相似文献
923.
Alexander S. de Resende Rogério P. Xavier Octávio C. de Oliveira Segundo Urquiaga Bruno J. R. Alves Robert M. Boddey 《Plant and Soil》2006,281(1-2):339-351
Since the 1970s the area under sugarcane in Brazil has increased from 2 million to over 5 million ha (M ha), and it is expected
to pass the 7 M ha mark in 2007. More than half of the cane is harvested to produce bioethanol as a fuel for light vehicles.
The distilleries produce approximately 13 L of distillery waste (vinasse) for each litre of ethanol produced. In the 1980s
there was considerable concern over the long-term effects of the disposal of this material (containing about 1% carbon and
high in K) on cane yields if it was applied to the field. At the same time there was a growing movement to abandon the practice
of pre-harvest burning and some research was showing that some Brazilian varieties of sugar cane were able to obtain significant
contributions of N from plant-associated biological nitrogen fixation (BNF). For these reasons an experiment was installed
on a cane plantation in the state of Pernambuco, NE Brazil to investigate the long-term effects of vinasse and N fertiliser
additions and the practice of pre-harvest burning on crop and sugar yield, soil fertility parameters, N balance and soil C
stocks. The results showed that over a 16-year period, trash conservation (abandonment of burning) increased cane yields by
25% from a mean of 46 to 58 Mg ha−1. Vinasse applications (80 m3 ha−1 crop−1) increased mean cane and sugar yield by 12 to 13% and the application of 80 kg N ha−1 as urea increased cane yields by 9%, but total sugar yield by less than 6% (from 7.0 to 7.4 Mg ha−1 crop−1). The total N balance for the soil/plant system when only the surface 20 cm of the soil was considered was positive in plots
where no N fertiliser was added. However, the data indicated that during the 16 years of the study considerable quantities
of soil organic matter were accumulated below 20 cm depth such that the N balance considering the soil to 60 cm depth was
strongly positive, except where N fertiliser was added. The data indicated that there were considerable BNF inputs to the
system, which was consistent with its low response to N fertiliser and low N fertiliser-use-efficiency. There were no significant
effects of vinasse or urea addition, or trash conservation on soil C stocks, although the higher yields proportioned by trash
conservation had potentially significant benefits for increased mitigation of CO2 emissions where the main use of the cane was for bioethanol production. 相似文献
924.
Mariac C Luong V Kapran I Mamadou A Sagnard F Deu M Chantereau J Gerard B Ndjeunga J Bezançon G Pham JL Vigouroux Y 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,114(1):49-58
Genetic diversity of crop species in sub-Sahelian Africa is still poorly documented. Among such crops, pearl millet is one of the most important staple species. In Niger, pearl millet covers more than 65% of the total cultivated area. Analyzing pearl millet genetic diversity, its origin and its dynamics is important for in situ and ex situ germplasm conservation and to increase knowledge useful for breeding programs. We developed new genetic markers and a high-throughput technique for the genetic analysis of pearl millet. Using 25 microsatellite markers, we analyzed genetic diversity in 46 wild and 421 cultivated accessions of pearl millet in Niger. We showed a significantly lower number of alleles and lower gene diversity in cultivated pearl millet accessions than in wild accessions. This result contrasts with a previous study using iso-enzyme markers showing similar genetic diversity between cultivated and wild pearl millet populations. We found a strong differentiation between the cultivated and wild groups in Niger. Analyses of introgressions between cultivated and wild accessions showed modest but statistically supported evidence of introgressions. Wild accessions in the central region of Niger showed introgressions of cultivated alleles. Accessions of cultivated pearl millet showed introgressions of wild alleles in the western, central, and eastern parts of Niger.Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.Cedric Mariac and Viviane Luong have contributed equally to this work. 相似文献
925.
Morais CN Carvalho BM Melo WG Lopes EP Domingues AL Jucá NT Souza W Abath FG Montenegro SM 《Memórias do Instituto Oswaldo Cruz》2006,101(Z1):353-354
Evaluation of hepatic fibrosis is usually performed by histopathological examination of biopsies. However, this is an invasive and potentially dangerous procedure. Several studies have proposed serum biological markers of hepatic fibrosis. This communication evaluates the use of serum cytokines as markers of hepatic fibrosis in hepatitis C, schistosomiasis, and co-infection. 相似文献
926.
Stockdale C Bruno M Ferreira H Garcia-Wilson E Wiechens N Engeholm M Flaus A Owen-Hughes T 《Biochemical Society symposium》2006,(73):109-119
In the 30 years since the discovery of the nucleosome, our picture of it has come into sharp focus. The recent high-resolution structures have provided a wealth of insight into the function of the nucleosome, but they are inherently static. Our current knowledge of how nucleosomes can be reconfigured dynamically is at a much earlier stage. Here, recent advances in the understanding of chromatin structure and dynamics are highlighted. The ways in which different modes of nucleosome reconfiguration are likely to influence each other are discussed, and some of the factors likely to regulate the dynamic properties of nucleosomes are considered. 相似文献
927.
928.
929.
Garcia C Robert M Arzul I Chollet B Joly JP Miossec L Comtet T Berthe F 《Diseases of aquatic organisms》2006,70(3):193-199
Viral gametocytic hypertrophy was reported for the first time in 2001 in Pacific oyster Crassostrea gigas in France. Since this date, the number of reported cases and the distribution area have increased every year; however, the cases are not associated with macroscopic signs or increased mortality rates. Both male and female gametes were hypertrophied and basophilic inclusions were observed in gamete nuclei. Transmission electron microscopy revealed the presence of viral particles in these intranuclear basophilic inclusions. These particles had characteristics similar to those of the Papillomaviridae and Polyoma viridae families: they were small, non-enveloped, icosahedral, and 44 to 56 nm in diameter. The viral particles were found in male, female and hermaphrodite oysters and no significant difference in viral infection was observed between those groups. The frequency of detection and the intensity of infection were low and no host defence reaction was recognised, suggesting that the viral particles had a weak impact on C. gigas. The viral particles described in the present study seem to be similar to these described in C. virginica in the USA and Canada and in C. gigas in Korea, but further studies are required to confirm their identity. The issue of a possible emergence of this infection is discussed. 相似文献
930.
Diaz BL Satake Y Kikawada E Balestrieri B Arm JP 《Biochimica et biophysica acta》2006,1761(12):1489-1497
Activation of mouse bone marrow-derived mast cells (BMMC) with stem cell factor (SCF) or IgE and antigen elicits exocytosis and an immediate phase of prostaglandin (PG) D(2) and leukotriene (LT) C(4) generation. Activation of BMMC by SCF, IL-1beta and IL-10 elicits a delayed phase of PGD(2) generation dependent on cyclooxygenase (COX) 2 induction. Cytosolic phospholipase A(2) alpha provides arachidonic acid in both phases and amplifies COX-2 induction. Pharmacological experiments implicate an amplifying role for secretory (s) PLA(2). We used mice lacking the gene encoding group V sPLA(2) (Pla2g5-/-) to definitively test its role in eicosanoid generation by BMMC. Pla2g5-/- BMMC on a C57BL/6 genetic background showed a modest reduction in exocytosis and immediate PGD(2) generation after activation with SCF or with IgE and antigen, while LTC(4) generation was not modified. Delayed-phase PGD(2) generation and COX-2 induction were reduced approximately 35% in C57BL/6 Pla2g5-/- BMMC and were restored by exogenous PGE(2). There was no deficit in either phase of eicosanoid generation by Pla2g5-/- BMMC on a BALB/c background. Thus, group V sPLA(2) amplifies COX-2 expression and delayed phase PGD(2) generation in a strain-dependent manner; it has at best a limited role in immediate eicosanoid generation by BMMC. 相似文献