bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mycorrhizal symbiosis stimulates endoreduplication in angiosperms
Authors: BAINARD L. D. , BAINARD J. D. , NEWMASTER S. G. , KLIRONOMOS J. N. 
Published: June 2011

ABSTRACTSymbiotic and parasitic relationships can alter the degree of endoreduplication in plant cells, and a limited number of studies have documented this occurrence in root cells colonized by arbuscular mycorrhizal (AM) fungi. However, this phenomenon has not been tested in a wide range of plant species, including species that are non‐endopolyploid and those that do not associate with AM fungi. We grew 37 species belonging to 16 plant families, with a range of genome sizes and a range in the degree of endopolyploidy. The endoreduplication index (EI) was compared between plants that were inoculated with Glomus irregulare and plants that were not inoculated. Of the species colonized with AM fungi, 22 of the 25 species had a significant increase in endopolyploid root nuclei over non‐mycorrhizal plants, including species that do not normally exhibit endopolyploidy. Changes in the EI were strongly correlated (R2 = 0.619) with the proportion of root length colonized by arbuscules. No change was detected in the EI for the 12 non‐mycorrhizal species. This work indicates that colonization by symbiotic fungi involves a mechanism to increase nuclear DNA content in roots across many angiosperm groups and is likely linked to increased metabolism and protein production.
Physiological impact of mitochondrial alternative oxidase on photosynthesis and growth in Arabidopsis thaliana
Authors: YOSHIDA KEISUKE , WATANABE CHIHIRO K. , TERASHIMA ICHIRO , NOGUCHI KO 
Published: June 2011

ABSTRACTThe mitochondrial alternative oxidase (AOX) has been suggested to have a beneficial role in illuminated leaves, but its function has not yet been fully elucidated. In this study, we investigated the effects of a knockout of the AOX1a gene on photosynthesis and growth under several light conditions in Arabidopsis thaliana. The AOX‐deficient aox1a mutant showed a lowered operating efficiency of photosystem II and an enhanced activity of cyclic electron transport around photosystem I (CET‐PSI) at high irradiance. To further address the physiological association of AOX with CET‐PSI, we crossed aox1a with the pgr5 mutant, which is impaired in CET‐PSI activity. In the pgr5 mutant background, AOX deficiency did not affect the apparent photosynthetic efficiency, indicating that the direct contribution of AOX to photosynthesis is not so large compared with CET‐PSI. Nevertheless, the growth of the aox1a pgr5 double mutant was significantly impaired depending on the light intensity under growth conditions. The possibility of a synergistic function of AOX with CET‐PSI in supporting plant growth is discussed.
Understanding the role of H2O2 during pea seed germination: a combined proteomic and hormone profiling approach
Authors: BARBA‐ESPÍN GREGORIO , DIAZ‐VIVANCOS PEDRO , JOB DOMINIQUE , BELGHAZI MAYA , JOB CLAUDETTE , HERNÁNDEZ JOSÉ ANTONIO 
Published: June 2011

ABSTRACTIn a previous publication, we showed that the treatment of pea seeds in the presence of hydrogen peroxide (H2O2) increased germination performance as well as seedling growth. To gain insight into the mechanisms responsible for this behaviour, we have analysed the effect of treating mature pea seeds in the presence of 20 mm H2O2 on several oxidative features such as protein carbonylation, endogenous H2O2 and lipid peroxidation levels. We report that H2O2 treatment of the pea seeds increased their endogenous H2O2 content and caused carbonylation of storage proteins and of several metabolic enzymes. Under the same conditions, we also monitored the expression of two MAPK genes known to be activated by H2O2 in adult pea plants. The expression of one of them, PsMAPK2, largely increased upon pea seed imbibition in H2O2, whereas no change could be observed in expression of the other, PsMAPK3. The levels of several phytohormones such as 1‐aminocyclopropane carboxylic acid, indole‐3‐acetic acid and zeatin appeared to correlate with the measured oxidative indicators and with the expression of PsMAPK2. Globally, our results suggest a key role of H2O2 in the coordination of pea seed germination, acting as a priming factor that involves specific changes at the proteome, transcriptome and hormonal levels.
Redox regulation in plant programmed cell death
Authors: DE PINTO M. C. , LOCATO V. , DE GARA L. 
Published: June 2011

ABSTRACTProgrammed cell death (PCD) is a genetically controlled process described both in eukaryotic and prokaryotic organisms. Even if it is clear that PCD occurs in plants, in response to various developmental and environmental stimuli, the signalling pathways involved in the triggering of this cell suicide remain to be characterized. In this review, the main similarities and differences in the players involved in plant and animal PCD are outlined. Particular attention is paid to the role of reactive oxygen species (ROS) as key inducers of PCD in plants. The involvement of different kinds of ROS, different sites of ROS production, as well as their interaction with other molecules, is crucial in activating PCD in response to specific stimuli. Moreover, the importance is stressed on the balance between ROS production and scavenging, in various cell compartments, for the activation of specific steps in the signalling pathways triggering this cell suicide process. The review focuses on the complexity of the interplay between ROS and antioxidant molecules and enzymes in determining the most suitable redox environment required for the occurrence of different forms of PCD.
Glycinebetaine enhances the tolerance of tomato plants to high temperature during germination of seeds and growth of seedlings
Authors: LI SHUFEN , LI FENG , WANG JIANWEI , ZHANG WEN , MENG QINGWEI , CHEN TONY H. H. , MURATA NORIO , YANG XINGHONG 
Published: June 2011

ABSTRACTTomato (Lycopersicon esculentum cv. ‘Moneymaker’) was transformed with a codA gene, from Arthrobacter globiformis, for choline oxidase that had been modified to allow targeting to both chloroplasts and the cytosol. Glycinebetaine (GB) accumulated in seeds of transformed plants up to 1 µmol g−1 dry weight (DW), while no detectable GB was found in wild‐type (WT) seeds. The codA‐transgenic seeds germinated faster and at higher frequency than WT seeds with high temperature treatment. After heat stress, levels of expression of a mitochondrial small heat‐shock protein (MT‐sHSP), heat‐shock protein 70 (HSP70) and heat‐shock cognate 70 (HSC70) were higher in transgenic seeds than in WT seeds during heat stress, and the accumulation of HSP70 was more prominent in codA‐transgenic seeds than in WT seeds. Addition of GB to the germination medium or imbibition of seeds in a solution of GB enhanced the tolerance of WT seeds to high temperatures. WT seeds treated with exogenous GB also expressed heat‐shock genes at elevated levels and accumulated more HSP70 than controls. Our results suggest that GB, either applied exogenously or accumulated in vivo in codA‐transgenic seeds, enhanced the expression of heat‐shock genes in and improved the tolerance to high temperature of tomato seeds during germination.
An Arabidopsis (malectin‐like) leucine‐rich repeat receptor‐like kinase contributes to downy mildew disease
Authors: HOK SOPHIE , DANCHIN ETIENNE G. J. , ALLASIA VALÉRIE , PANABIÈRES FRANCK , ATTARD AGNÈS , KELLER HARALD 
Published: June 2011

ABSTRACTBiotrophic filamentous plant pathogens frequently establish intimate contact with host cells through intracellular feeding structures called haustoria. To form and maintain these structures, pathogens must avoid or suppress defence responses and reprogramme the host cell. We used Arabidopsis whole‐genome microarrays to characterize genetic programmes that are deregulated during infection by the biotrophic' oomycete downy mildew pathogen, Hyaloperonospora arabidopsidis. Marked differences were observed between early and late stages of infection, but a gene encoding a putative leucine‐rich repeat receptor‐like kinase (LRR‐RLK) was constantly up‐regulated. We investigated the evolutionary history of this gene and noticed it being one of the first to have emerged from a common ancestral gene that gave rise to a cluster of 11 genes through duplications. The encoded LRR‐RLKs harbour an extracellular malectin‐like (ML) domain in addition to a short stretch of leucine‐rich repeats, and are thus similar to proteins from the symbiosis receptor‐like kinase family. Detailed expression analysis showed that the pathogen‐responsive gene was locally expressed in cells surrounding the oomycete. A knockout mutant showed reduced downy mildew infection, but susceptibility was fully restored through complementation of the mutation, suggesting that the (ML‐)LRR‐RLK contributes to disease. According to the mutant phenotype, we denominated it Impaired Oomycete Susceptibility 1 (IOS1).
Effect of ammonium/nitrate ratio in nutrient solution on control of Fusarium wilt of tomato by Trichoderma asperellum T34
Authors: Borrero C. , Trillas M.I. , Delgado A. , Avilés M. 
Published: June 2011

The behaviour of Fusarium oxysporum f.sp. lycopersici (Fol) and the effectiveness of the microbial control agent Trichoderma asperellum strain T34 were examined in hydroponically grown tomato plants under five ammonium/nitrate ratios. The results showed that disease severity was reduced by the action of T34 under increasing concentrations of ammonia. Furthermore, rhizosphere F. oxysporum populations decreased with T34 application. The presence of T34 augmented leaf nitrogen concentration in treatments infested with Fol. In addition, T34 application reduced iron concentration in tomato leaves at high ammonium/nitrate ratios and reduced the severity of Fusarium wilt at high iron and nitrogen leaf concentrations.
Similar Superantigen Gene Profiles and Superantigen Activity in Norwegian Isolates of Invasive and Non‐Invasive Group A Streptococci
Authors: Michaelsen T. E. , Andreasson I. K. G. , Langerud B. K. , Caugant D. A. 
Published: June 2011

AbstractGroup A streptococcus (GAS) harbours several virulence factors, including M protein (coded by the emm gene) and superantigens (SAgs). SAgs are extracellular toxins that directly activate the immune system by cross‐binding to the HLA class II molecule and T cell receptor (TCR), thereby causing activation of up to 30% of the T cells and subsequent massive secretion of cytokines. Forty‐eight GAS strains isolated from patients at Norwegian hospitals between 1988 and 2004 were included in this study. Of these, 24 were invasive streptococcal toxic shock syndrome (STSS) or necrotizing fasciitis (NF) isolates and 24 were non‐invasive pharyngitis isolates, matched for having the same T‐type and year of isolation as the invasive isolates. The isolates were characterized by emm sequence typing, multilocus sequence typing (MLST) and SAg gene profiles. A correlation between T‐type, emm type, sequence type and SAg gene profile was revealed. No difference between invasive and non‐invasive isolates regarding serotype or genotype was demonstrated. Selected invasive and non‐invasive isolates with identical SAg gene profiles were analysed for SAg activity in bacterial growth culture media with and without human cell culture media added. A human T cell proliferation assay was used as measurement for SAg activity and simultaneously we also measured the cytokine content in normal human peripheral blood leucocyte cell culture media. The results revealed that invasive and non‐invasive isolates did not differ significantly in SAg activity as it is present in semipurified bacterial culture medium.
The Ammarnäs Complex in the central Scandinavian Caledonides: an allochthonous basin fragment in the foreland of the Sveconorwegian orogen?
Authors: Grimmer J. C. , Greiling R. O. , Gerdes A. 
Published: June 2011

Terra Nova, 23, 270–279, 2011AbstractThe Ammarnäs Complex is a tectonic unit in the Middle Allochthon of the central Scandinavian Caledonides and consists of several hundred metres of thick uniform meta‐greywacke successions of greenschist metamorphic grade containing kilometre‐scale lenses of pre‐Caledonian crystalline basement rocks. Meta‐greywacke samples were analysed for major and trace elements and U‐Pb isotopes. Lithoclasts and geochemical data indicate that the greywackes were derived from granitic–granodioritic rocks. Detrital zircon dating yielded 7% Neoproterozoic, 52% Mesoproterozoic and 41% Palaeoproterozoic 207Pb/206Pb ages with two prominent age peaks at 1.64 and 1.5 Ga and a broad distribution of Sveconorwegian (1140–900 Ma) and ‘pre‐Sveconorwegian’ (1340–1140 Ma) ages. We interpret the Ammarnäs Complex as a former Neoproterozoic basin in the foreland of the Sveconorwegian orogen, which escaped major pre‐Caledonian magmatism–metamorphism and which was most likely deposited between c. 920 and 630 Ma.Terra Nova, 00, 1–10, 2011
The charophycean green algae provide insights into the early origins of plant cell walls
Authors: Sørensen Iben , Pettolino Filomena A. , Bacic Antony , Ralph John , Lu Fachuang , O’Neill Malcolm A. , Fei Zhangzhun , Rose Jocelyn K. C. , Domozych David S. , Willats William G. T. 
Published: June 2011

SummaryNumerous evolutionary innovations were required to enable freshwater green algae to colonize terrestrial habitats and thereby initiate the evolution of land plants (embryophytes). These adaptations probably included changes in cell‐wall composition and architecture that were to become essential for embryophyte development and radiation. However, it is not known to what extent the polymers that are characteristic of embryophyte cell walls, including pectins, hemicelluloses, glycoproteins and lignin, evolved in response to the demands of the terrestrial environment or whether they pre‐existed in their algal ancestors. Here we show that members of the advanced charophycean green algae (CGA), including the Charales, Coleochaetales and Zygnematales, but not basal CGA (Klebsormidiales and Chlorokybales), have cell walls that are comparable in several respects to the primary walls of embryophytes. Moreover, we provide both chemical and immunocytochemical evidence that selected Coleochaete species have cell walls that contain small amounts of lignin or lignin‐like polymers derived from radical coupling of hydroxycinnamyl alcohols. Thus, the ability to synthesize many of the components that characterize extant embryophyte walls evolved during divergence within CGA. Our study provides new insight into the evolutionary window during which the structurally complex walls of embryophytes originated, and the significance of the advanced CGA during these events.
Arabidopsis thaliana alpha1,2‐glucosyltransferase (ALG10) is required for efficient N‐glycosylation and leaf growth
Authors: Farid Akhlaq , Pabst Martin , Schoberer Jennifer , Altmann Friedrich , Glössl Josef , Strasser Richard 
Published: June 2011

SummaryAssembly of the dolichol‐linked oligosaccharide precursor (Glc3Man9GlcNAc2) is highly conserved among eukaryotes. In contrast to yeast and mammals, little is known about the biosynthesis of dolichol‐linked oligosaccharides and the transfer to asparagine residues of nascent polypeptides in plants. To understand the biological function of these processes in plants we characterized the Arabidopsis thaliana homolog of yeast ALG10, the α1,2‐glucosyltransferase that transfers the terminal glucose residue to the lipid‐linked precursor. Expression of an Arabidopsis ALG10–GFP fusion protein in Nicotiana benthamiana leaf epidermal cells revealed a reticular distribution pattern resembling endoplasmic reticulum (ER) localization. Analysis of lipid‐linked oligosaccharides showed that Arabidopsis ALG10 can complement the yeast Δalg10 mutant strain. A homozygous Arabidopsis T‐DNA insertion mutant (alg10‐1) accumulated mainly lipid‐linked Glc2Man9GlcNAc2 and displayed a severe protein underglycosylation defect. Phenotypic analysis of alg10‐1 showed that mutant plants have altered leaf size when grown in soil. Moreover, the inactivation of ALG10 in Arabidopsis resulted in the activation of the unfolded protein response, increased salt sensitivity and suppression of the phenotype of α‐glucosidase I‐deficient plants. In summary, these data show that Arabidopsis ALG10 is an ER‐resident α1,2‐glucosyltransferase that is required for lipid‐linked oligosaccharide biosynthesis and subsequently for normal leaf development and abiotic stress response.
Corn hybrids display lower metabolite variability and complex metabolite inheritance patterns
Authors: Lisec Jan , Römisch‐Margl Lilla , Nikoloski Zoran , Piepho Hans‐Peter , Giavalisco Patrick , Selbig Joachim , Gierl Alfons , Willmitzer Lothar 
Published: June 2011

SummaryWe conducted a comparative analysis of the root metabolome of six parental maize inbred lines and their 14 corresponding hybrids showing fresh weight heterosis. We demonstrated that the metabolic profiles not only exhibit distinct features for each hybrid line compared with its parental lines, but also separate reciprocal hybrids. Reconstructed metabolic networks, based on robust correlations between metabolic profiles, display a higher network density in most hybrids as compared with the corresponding inbred lines. With respect to metabolite level inheritance, additive, dominant and overdominant patterns are observed with no specific overrepresentation. Despite the observed complexity of the inheritance pattern, for the majority of metabolites the variance observed in all 14 hybrids is lower compared with inbred lines. Deviations of metabolite levels from the average levels of the hybrids correlate negatively with biomass, which could be applied for developing predictors of hybrid performance based on characteristics of metabolite patterns.
The APC/C subunit 10 plays an essential role in cell proliferation during leaf development
Authors: Eloy Nubia B. , de Freitas Lima Marcelo , Van Damme Daniël , Vanhaeren Hannes , Gonzalez Nathalie , De Milde Liesbeth , Hemerly Adriana S. , Beemster Gerrit T. S. , Inzé Dirk , Ferreira Paulo C. G. 
Published: June 2011

SummaryThe largest E3 ubiquitin‐ligase complex, known as anaphase‐promoting complex/cyclosome (APC/C), regulates the proteolysis of cell cycle regulators such as CYCLIN B and SECURIN that are essential for sister‐chromatid separation and exit from mitosis. Despite its importance, the role of APC/C in plant cells and the regulation of its activity during cell division remain poorly understood. Here, the Arabidopsis thaliana APC/C subunit APC10 was characterized and shown to functionally complement an apc10 yeast mutant. The APC10 protein was located in specific nuclear bodies, most probably resulting from its association with the proteasome complex. An apc10 Arabidopsis knockout mutant strongly impaired female gametogenesis. Surprisingly, constitutive overexpression of APC10 enhanced leaf size. Through kinematic analysis, the increased leaf size was found to be due to enhanced rates of cell division during the early stages of leaf development and, at the molecular level, by increased APC/C activity as measured by an amplification of the proteolysis rate of the mitotic cyclin, CYCB1;1.
The pathway of triacylglycerol synthesis through phosphatidylcholine in Arabidopsis produces a bottleneck for the accumulation of unusual fatty acids in transgenic seeds
Authors: Bates Philip D. , Browse John 
Published: June 2011

SummaryEngineering of oilseed plants to accumulate unusual fatty acids (FAs) in seed triacylglycerol (TAG) requires not only the biosynthetic enzymes for unusual FAs but also efficient utilization of the unusual FAs by the host‐plant TAG biosynthetic pathways. Competing pathways of diacylglycerol (DAG) and subsequent TAG synthesis ultimately affect TAG FA composition. The membrane lipid phosphatidylcholine (PC) is the substrate for many FA‐modifying enzymes (desaturases, hydroxylases, etc.) and DAG can be derived from PC for TAG synthesis. The relative proportion of PC‐derived DAG versus de novo synthesized DAG utilized for TAG synthesis, and the ability of each pathway to utilize unusual FA substrates, are unknown for most oilseed plants, including Arabidopsis thaliana. Through metabolic labeling experiments we demonstrate that the relative flux of de novo DAG into the PC‐derived DAG pathway versus direct conversion to TAG is ∼14/1 in wild‐type Arabidopsis. Expression of the Ricinus communis FA hydroxylase reduced the flux of de novo DAG into PC by ∼70%. Synthesis of TAG directly from de novo DAG did not increase, resulting in lower total synthesis of labeled lipids. Hydroxy‐FA containing de novo DAG was rapidly synthesized, but it was not efficiently accumulated or converted to PC and TAG, and appeared to be in a futile cycle of synthesis and degradation. However, FA hydroxylation on PC and conversion to DAG allowed some hydroxy‐FA to accumulate in sn‐2 TAG. Therefore, the flux of DAG through PC represents a major bottleneck for the accumulation of unusual FAs in TAG of transgenic Arabidopsis seeds.
Red cell concentrate storage and transport temperature
Authors: Hancock V. , Cardigan R. , Thomas S. 
Published: June 2011

Background and Objectives: This study investigated the current UK guidelines for storage and transport of red cell concentrates (RCC) in saline, adenine, glucose and mannitol (SAGM). The guidelines stipulate storage at 2–6 °C but allow exposure to between 1–10 °C core temperature in a single occurrence of less than 5 h and a surface temperature of 2–10 °C for no more than 12 h during transportation.Methods and Materials: Twenty RCC units in SAGM were selected on the day of blood collection (day 0) and in vitro quality was tested pre‐ and post‐temperature deviation at 10 °C and up to day 42 of storage. Each group of 10 RCC units was incubated for either 12 h or for both 5 and 12 h.Results: Haemolysis was below the 0·8% UK limit at day 42 in all units, although there was an unexpected trend towards lower haemolysis in packs incubated for 5 and 12 h rather than just 12 h alone. Supernatant potassium was significantly higher than reference data on day 35 (P < 0·05) with a maximum of 58 mmol L−1 and day 42 (P < 0·001). All units incubated at 10 °C had comparable levels of adenosine triphosphate and, 2,3‐diphosphoglycerate to reference data from previous studies, throughout storage.Conclusion: These results suggest that exposure to 10 °C for 12 h or for 5 and 12 h did not adversely affect in vitro red cell quality for the remainder of the components shelf life.
Applying lessons learnt from the ‘DOTS’ Tuberculosis Model to monitoring and evaluating persons with diabetes mellitus in Blantyre, Malawi
Authors: Allain Theresa J. , van Oosterhout Joep J. , Douglas Gerald P. , Joukes Sabine , Gadabu Oliver J. , Darts Christopher , Kapur Anil , Harries Anthony D. 
Published: June 2011

SummaryThe global burden of diabetes mellitus (DM) is immense and predicted to reach 438 million by 2030, with 80% of the cases being in the developing world. The management of chronic non‐communicable diseases like DM is poor in most resource‐limited settings, and the ‘directly observed therapy, short course’ (DOTS) framework for tuberculosis control has been proposed as a feasible way to improve this situation. In late 2009, aspects of the DOTS model were applied to the management of persons with DM in the diabetes clinic in Queen Elizabeth Central Hospital, Blantyre, Malawi, and a point‐of‐care electronic medical record system was set up to support and monitor patients in care. This is the first quarterly and cumulative report of persons with DM registered for care stratified by treatment outcomes, complications and medication history up to 31 December 2010. There were 170 new patients registered between October and December 2010, with 1864 ever registered by 31 December 2010. Most patients were alive and in care; 3 died, 53 defaulted and 3 transferred out. Of those on oral hypoglycaemic agents, metformin was most commonly used. Complications were common. The monitoring and evaluation will be further refined, and at the same time, the systems developed in Blantyre will be expanded to other parts of the country.