Comparative analysis of expressed genes from cacao meristems infected by Moniliophthora perniciosa

BACKGROUND AND AIMS: Witches' broom disease is caused by the hemibiotrophic basidiomycete Moniliophthora perniciosa, and is one of the most important diseases of cacao in the western hemisphere. Because very little is known about the global process of such disease development, expressed sequence tags (ESTs) were used to identify genes expressed during the Theobroma cacao-Moniliophthora perniciosa interaction. METHODS: Two cDNA libraries corresponding to the resistant (RT) and susceptible (SP) cacao-M. perniciosa interactions were constructed from total RNA, using the DB SMART Creator cDNA library kit (Clontech). Clones were randomly selected, sequenced from the 5' end and analysed using bioinformatics tools including in silico analysis of the differential gene expression. KEY RESULTS: A total of 6884 ESTs were generated from the RT and SP cDNA libraries. These ESTs were composed of 2585 singlets and 341 contigs for a total of 2926 non-redundant sequences. The redundancy of the libraries was low and their specificity high when compared with the few other cacao libraries already published. Sequence analysis allowed the assignment of a putative functional category for 54 % of sequences, whereas approx. 22 % of sequences corresponded to unknown function and approx. 24 % of sequences did not show any significant similarity with other proteins present in the database. Despite the similar overall distribution of the sequences in functional categories between the two libraries, qualitative differences were observed. Genes involved during the defence response to pathogen infection or in programmed cell death were identified, such as pathogenesis related-proteins, trypsin inhibitor or oxalate oxidase, and some of them showed an in silico differential expression between the resistant and the susceptible interactions. CONCLUSIONS: As far as is known this is the first EST resource from the cacao-M. perniciosa interaction and it is believed that it will provide a significant contribution to the understanding of the molecular mechanisms of the resistance and susceptibility of cacao to M. perniciosa, to develop strategies to control witches' broom, and as a source of polymorphism for molecular marker development and marker-assisted selection.     

Alterations in Protective Enzymes Against Peroxidation in the Central and Peripheral Nervous System of Control and Dysmyelinating Mutant Mice

The activities of peroxide-detoxifying enzymes such as superoxide dismutase (SOD), glutathione peroxidase, glutathione reductase, and catalase were measured in the nervous system of neurological dysmyelinating mutants: quaking (Qk), shiverer (Shi), and trembler (Tr) mice. Cu/Zn-SOD activity was higher in the cerebellum of Qk and Shi mice (by 53% and 106%, respectively) in comparison with controls, but it was the same in the cerebellum of Tr mice and their corresponding controls. In contrast, there was no difference in the level of Cu/Zn-SOD activity in the cerebrum of Qk, Shi, and Tr mice and their respective controls. Mn-SOD activity was the same among all the mutants compared to control animals in both cerebrum and cerebellum. In Shi cerebellum, glutathione peroxidase and glutathione reductase activities were slightly decreased (a 21.6% and a 13.2% diminution, respectively), whereas catalase activity in cerebrum and cerebellum was the same among mutants and control mice. In the sciatic nerve from Tr mice, all the enzymatic activities were enhanced: sixfold increase for total SOD, and 2.4-fold, 3.5-fold, and 1.8-fold increase for glutathione peroxidase, glutathione reductase, and catalase, respectively.     

Animal behaviour shapes the ecological effects of ocean acidification and warming: moving from individual to community‐level responses

Biological communities are shaped by complex interactions between organisms and their environment as well as interactions with other species. Humans are rapidly changing the marine environment through increasing greenhouse gas emissions, resulting in ocean warming and acidification. The first response by animals to environmental change is predominantly through modification of their behaviour, which in turn affects species interactions and ecological processes. Yet, many climate change studies ignore animal behaviour. Furthermore, our current knowledge of how global change alters animal behaviour is mostly restricted to single species, life phases and stressors, leading to an incomplete view of how coinciding climate stressors can affect the ecological interactions that structure biological communities. Here, we first review studies on the effects of warming and acidification on the behaviour of marine animals. We demonstrate how pervasive the effects of global change are on a wide range of critical behaviours that determine the persistence of species and their success in ecological communities. We then evaluate several approaches to studying the ecological effects of warming and acidification, and identify knowledge gaps that need to be filled, to better understand how global change will affect marine populations and communities through altered animal behaviours. Our review provides a synthesis of the far‐reaching consequences that behavioural changes could have for marine ecosystems in a rapidly changing environment. Without considering the pervasive effects of climate change on animal behaviour we will limit our ability to forecast the impacts of ocean change and provide insights that can aid management strategies.     

The Argasidae, Ixodidae and Nuttalliellidae (Acari: Ixodida): A World List of Valid Tick Names

The world's argasid tick fauna comprises 183 species in four genera, namely Argas, Carios, Ornithodoros and Otobius in the family Argasidae. The ixodid tick fauna consists of 241 species in the genus Ixodes and 442 species in the genera Amblyomma, Anomalohimalaya, Bothriocroton, Cosmiomma, Dermacentor, Haemaphysalis, Hyalomma, Margaropus, Nosomma, Rhipicentor and Rhipicephalus in the family Ixodidae, with the genus Boophilus becoming a subgenus of the genus Rhipicephalus. The family Nuttalliellidae is represented by the monospecific genus Nuttalliella. The species names of these ticks, based on seven previous complete or partial listings, as well as those of recently described new species, are presented in tabular format. This revised version was published online in July 2006 with corrections to the Cover Date.     

Auxin and the developing root of Arabidopsis thaliana

The plant hormone auxin has long been known to play a crucial role in plant growth and development, but how it affects so many different processes has remained a mystery. Recent evidence from genetic and molecular studies has begun to reveal a possible mechanism for auxin action. In this article we will present an overview with specific emphasis on auxin's role in roots of Arabidopsis thaliana , focusing on cell division, elongation and differentiation.     

Transformation of metals and metal ions by hydrogenases from phototrophic bacteria

The ability of hydrogenases isolated from Thiocapsa roseopersicina and Lamprobacter modestohalophilus to reduce metal ions and oxidize metals has been studied. Hydrogenases from both phototrophic bacteria oxidized metallic Fe, Cd, Zn and Ni into their ionic forms with simultaneous evolution of molecular hydrogen. The metal oxidation rate decreased in the series Zn>Fe>Cd>Ni and depended on the pH. The presence of methyl viologen in the reaction system accelerated this process. T. roseopersicina and L. modestohalophilus cells and their hydrogenases reduced Ni(II), Pt(IV), Pd(II) or Ru(III) to their metallic forms under H₂ atmosphere. These results suggest that metals or metal ions can serve as electron donors or acceptors for hydrogenases from phototrophic bacteria.     

Life Cycle Assessment of Water Supply Plans in Mediterranean Spain

Life cycle assessment (LCA) was used to compare the current water supply planning in Mediterranean Spain, the so‐called AGUA Programme, with its predecessor, the Ebro river water transfer (ERWT). Whereas the ERWT was based on a single interbasin transfer, the AGUA Programme excludes new transfers and focuses instead on different types of resources, including seawater and brackish water desalination and wastewater reuse, among others. The study includes not only water supply but the whole anthropic cycle of water, from water abstraction to wastewater treatment. In addition to standard LCA impact categories, a specific impact category focusing on freshwater resources is included, which takes into account freshwater scarcity in the affected water catchments. In most impact categories the AGUA Programme obtains similar or even lower impact scores than ERWT. Concerning impacts on freshwater resources, the AGUA Programme obtains an impact score 49% lower than the ERWT. Although the current water planning appears to perform better in many impact categories than its predecessor, this study shows that water supply in Spanish Mediterranean regions is substantially increasing its energy intensity and that Mediterranean basins suffer a very high level of water stress due to increasing demand and limited resources.     

Paramagnetic relaxation enhancements in unfolded proteins: Theory and application to drkN SH3 domain

Site‐directed spin labeling in combination with paramagnetic relaxation enhancement (PRE) measurements is one of the most promising techniques for studying unfolded proteins. Since the pioneering work of Gillespie and Shortle (J Mol Biol 1997;268:158), PRE data from unfolded proteins have been interpreted using the theory that was originally developed for rotational spin relaxation. At the same time, it can be readily recognized that the relative motion of the paramagnetic tag attached to the peptide chain and the reporter spin such as ¹H^N is best described as a translation. With this notion in mind, we developed a number of models for the PRE effect in unfolded proteins: (i) mutual diffusion of the two tethered spheres, (ii) mutual diffusion of the two tethered spheres subject to a harmonic potential, (iii) mutual diffusion of the two tethered spheres subject to a simulated mean‐force potential (Smoluchowski equation); (iv) explicit‐atom molecular dynamics simulation. The new models were used to predict the dependences of the PRE rates on the ¹H^N residue number and static magnetic field strength; the results are appreciably different from the Gillespie–Shortle model. At the same time, the Gillespie–Shortle approach is expected to be generally adequate if the goal is to reconstruct the distance distributions between ¹H^N spins and the paramagnetic center (provided that the characteristic correlation time is known with a reasonable accuracy). The theory has been tested by measuring the PRE rates in three spin‐labeled mutants of the drkN SH3 domain in 2M guanidinium chloride. Two modifications introduced into the measurement scheme—using a reference compound to calibrate the signals from the two samples (oxidized and reduced) and using peak volumes instead of intensities to determine the PRE rates—lead to a substantial improvement in the quality of data. The PRE data from the denatured drkN SH3 are mostly consistent with the model of moderately expanded random‐coil protein, although part of the data point toward a more compact structure (local hydrophobic cluster). At the same time, the radius of gyration reported by Choy et al. (J Mol Biol 2002;316:101) suggests that the protein is highly expanded. This seemingly contradictory evidence can be reconciled if one assumes that denatured drkN SH3 forms a conformational ensemble that is dominated by extended conformations, yet also contains compact (collapsed) species. Such behavior is apparently more complex than predicted by the model of a random‐coil protein in good solvent/poor solvent.