Hygienic characteristics of radishes grown in soil contaminated with Stenotrophomonas maltophilia

Background: Stenotrophomonas maltophilia is a plant growth-promoter. This bacterium is also implicated in human diseases. Thus, after the use of this bacterium in agriculture, the safety of the final products has to be verified. Due to the ubiquitous presence of S. maltophilia in soil, in this study a massive contamination was simulated to evaluate the growth and safety of Raphanus sativus L.. Results: Different inoculums and soil treatment conditions were tested. Soils were analysed weekly and the radishes at harvest for their microbial loads and presence/persistence of S. maltophilia LMG 6606. The concentration of the bacterium added in the different trials decreased during the first week, but increased thereafter and determined a significant increase of growth parameters of radishes. Conclusions: The addition of S. maltophilia LMG 6606 to non-autoclaved soil enhanced the productivity of radishes. The bacterium did not internalize in the hypocotyls, but colonized the external surface ensuring the safety of the products. Thus, a sanitizing bath of hypocotyls before consumption is necessary

Wheat seed embryo excision enables the creation of axenic seedlings and Koch’s postulates testing of putative bacterial endophytes

Early establishment of endophytes can play a role in pathogen suppression and improve seedling development. One route for establishment of endophytes in seedlings is transmission of bacteria from the parent plant to the seedling via the seed. In wheat seeds, it is not clear whether this transmission route exists, and the identities and location of bacteria within wheat seeds are unknown. We identified bacteria in the wheat (Triticum aestivum) cv. Hereward seed environment using embryo excision to determine the location of the bacterial load. Axenic wheat seedlings obtained with this method were subsequently used to screen a putative endophyte bacterial isolate library for endophytic competency. This absence of bacteria recovered from seeds indicated low bacterial abundance and/or the presence of inhibitors. Diversity of readily culturable bacteria in seeds was low with 8 genera identified, dominated by Erwinia and Paenibacillus. We propose that anatomical restrictions in wheat limit embryo associated vertical transmission, and that bacterial load is carried in the seed coat, crease tissue and endosperm. This finding facilitates the creation of axenic wheat plants to test competency of putative endophytes and also provides a platform for endophyte competition, plant growth, and gene expression studies without an indigenous bacterial background

Spontaneous Reorientation Is Guided by Perceived Surface Distance, Not by Image Matching Or Comparison

Humans and animals recover their sense of position and orientation using properties of the surface layout, but the processes underlying this ability are disputed. Although behavioral and neurophysiological experiments on animals long have suggested that reorientation depends on representations of surface distance, recent experiments on young children join experimental studies and computational models of animal navigation to suggest that reorientation depends either on processing of any continuous perceptual variables or on matching of 2D, depthless images of the landscape. We tested the surface distance hypothesis against these alternatives through studies of children, using environments whose 3D shape and 2D image properties were arranged to enhance or cancel impressions of depth. In the absence of training, children reoriented by subtle differences in perceived surface distance under conditions that challenge current models of 2D-image matching or comparison processes. We provide evidence that children’s spontaneous navigation depends on representations of 3D layout geometry.National Institutes of Health (U.S.) (Grant HD 23103

Dynamics of Seed-Borne Rice Endophytes on Early Plant Growth Stages

Bacterial endophytes are ubiquitous to virtually all terrestrial plants. With the increasing appreciation of studies that unravel the mutualistic interactions between plant and microbes, we increasingly value the beneficial functions of endophytes that improve plant growth and development. However, still little is known on the source of established endophytes as well as on how plants select specific microbial communities to establish associations. Here, we used cultivation-dependent and -independent approaches to assess the endophytic bacterrial community of surface-sterilized rice seeds, encompassing two consecutive rice generations. We isolated members of nine bacterial genera. In particular, organisms affiliated with Stenotrophomonas maltophilia and Ochrobactrum spp. were isolated from both seed generations. PCR-based denaturing gradient gel electrophoresis (PCR-DGGE) of seed-extracted DNA revealed that approximately 45% of the bacterial community from the first seed generation was found in the second generation as well. In addition, we set up a greenhouse experiment to investigate abiotic and biotic factors influencing the endophytic bacterial community structure. PCR-DGGE profiles performed with DNA extracted from different plant parts showed that soil type is a major effector of the bacterial endophytes. Rice plants cultivated in neutral-pH soil favoured the growth of seed-borne Pseudomonas oryzihabitans and Rhizobium radiobacter, whereas Enterobacter-like and Dyella ginsengisoli were dominant in plants cultivated in low-pH soil. The seed-borne Stenotrophomonas maltophilia was the only conspicuous bacterial endophyte found in plants cultivated in both soils. Several members of the endophytic community originating from seeds were observed in the rhizosphere and surrounding soils. Their impact on the soil community is further discussed

A Naturally Associated Rhizobacterium of Arabidopsis thaliana Induces a Starvation-Like Transcriptional Response while Promoting Growth

Plant growth promotion by rhizobacteria is a known phenomenon but the underlying mechanisms are poorly understood. We searched for plant growth-promoting rhizobacteria that are naturally associated with Arabidopsis thaliana to investigate the molecular mechanisms that are involved in plant growth-promotion. We isolated a Pseudomonas bacterium (Pseudomonas sp. G62) from roots of field-grown Arabidopsis plants that has not been described previously and analyzed its effect on plant growth, gene expression and the level of sugars and amino acids in the host plant. Inoculation with Pseudomonas sp. G62 promoted plant growth under various growth conditions. Microarray analysis revealed rapid changes in transcript levels of genes annotated to energy-, sugar- and cell wall metabolism in plants 6 h after root inoculation with P. sp. G62. The expression of several of these genes remained stable over weeks, but appeared differentially regulated in roots and shoots. The global gene expression profile observed after inoculation with P. sp. G62 showed a striking resemblance with previously described carbohydrate starvation experiments, although plants were not depleted from soluble sugars, and even showed a slight increase of the sucrose level in roots 5 weeks after inoculation. We suggest that the starvation-like transcriptional phenotype - while steady state sucrose levels are not reduced - is induced by a yet unknown signal from the bacterium that simulates sugar starvation. We discuss the potential effects of the sugar starvation signal on plant growth promotion

Augmented Reality for the assessment of children's spatial memory in real settings

Short-term memory can be defined as the capacity for holding a small amount of information in mind in an active state for a short period of time. There are no available, specific, and adapted instruments to study the development of memory and spatial orientation in people while they are moving. In this paper, we present the ARSM (Augmented Reality Spatial Memory) task, the first Augmented Reality task that involves a user's movement to assess spatial short-term memory in healthy children. The experimental procedure of the ARSM task was designed to assess the children s skill to retain visuospatial information. They were individually asked to remember the real place where augmented reality objects were located. The children (N=76) were divided into two groups: preschool (5-6 year olds) and primary school (7-8 year olds). We found a significant improvement in ARSM task performance in the older group. The correlations between scores for the ARSM task and traditional procedures were significant. These traditional procedures were the Dot Matrix subtest for the assessment of visuospatial short-term memory of the computerized AWMA-2 battery and a parent s questionnaire about a child s everyday spatial memory. Hence, we suggest that the ARSM task has high verisimilitude with spatial short-term memory skills in real life. In addition, we evaluated the ARSM task s usability and perceived satisfaction. The study revealed that the younger children were more satisfied with the ARSM task. This novel instrument could be useful in detecting visuospatial short-term difficulties that affect school academic achievementFunded by the Spanish Government (MINECO) and European Regional Development Fund (FEDER) in the CHILDMNEMOS project TIN2012-37381-C02-01, Gobierno de Aragon (Dpt. Industria e Innovacion), Fondo Social Europeo, Fundacion Universitaria Antonio Gargallo and Obra Social Ibercaja. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Juan, M.; Mendez Lopez, M.; Pérez Hernández, E.; Albiol Pérez, S. (2014). Augmented Reality for the assessment of children's spatial memory in real settings. PLoS ONE. 9(12):113751-113771. https://doi.org/10.1371/journal.pone.0113751S113751113771912Linn, M. C., & Petersen, A. C. (1985). Emergence and Characterization of Sex Differences in Spatial Ability: A Meta-Analysis. Child Development, 56(6), 1479. doi:10.2307/1130467Simmons, F. R., Willis, C., & Adams, A.-M. (2012). Different components of working memory have different relationships with different mathematical skills. Journal of Experimental Child Psychology, 111(2), 139-155. doi:10.1016/j.jecp.2011.08.011Alloway, T. P., & Alloway, R. G. (2010). Investigating the predictive roles of working memory and IQ in academic attainment. Journal of Experimental Child Psychology, 106(1), 20-29. doi:10.1016/j.jecp.2009.11.003Bavin, E. L., Wilson, P. H., Maruff, P., & Sleeman, F. (2005). Spatio‐visual memory of children with specific language impairment: evidence for generalized processing problems. International Journal of Language & Communication Disorders, 40(3), 319-332. doi:10.1080/13682820400027750Szucs, D., Devine, A., Soltesz, F., Nobes, A., & Gabriel, F. (2013). Developmental dyscalculia is related to visuo-spatial memory and inhibition impairment. Cortex, 49(10), 2674-2688. doi:10.1016/j.cortex.2013.06.007Mammarella, I. C., & Cornoldi, C. (2013). An analysis of the criteria used to diagnose children with Nonverbal Learning Disability (NLD). Child Neuropsychology, 20(3), 255-280. doi:10.1080/09297049.2013.796920Alloway TP (2007) Automated Working Memory Assessment. London: The Psychological Corporation.Oades, R. D., & Isaacson, R. L. (1978). The development of food search behavior by rats: The effects of hippocampal damage and haloperidol. Behavioral Biology, 24(3), 327-337. doi:10.1016/s0091-6773(79)90184-6Morris, R. (1984). Developments of a water-maze procedure for studying spatial learning in the rat. Journal of Neuroscience Methods, 11(1), 47-60. doi:10.1016/0165-0270(84)90007-4Olton, D. S. (1987). The radial arm maze as a tool in behavioral pharmacology. Physiology & Behavior, 40(6), 793-797. doi:10.1016/0031-9384(87)90286-1Méndez-López, M., Méndez, M., López, L., & Arias, J. L. (2009). Sexually dimorphic c-Fos expression following spatial working memory in young and adult rats. Physiology & Behavior, 98(3), 307-317. doi:10.1016/j.physbeh.2009.06.006Munoz M, Morris RGM (2009) Episodic memory in animals. In:Squire LR editor. New Encyclopedia of Neuroscience. Oxford: Academic Press. pp.1173–1182.SHORE, D. I., STANFORD, L., MACINNES, W. J., KLEIN, R. M., & BROWN, R. E. (2001). Of mice and men: Virtual Hebb-Williams mazes permit comparison of spatial learning across species. Cognitive, Affective, & Behavioral Neuroscience, 1(1), 83-89. doi:10.3758/cabn.1.1.83Astur, R. S., Taylor, L. B., Mamelak, A. N., Philpott, L., & Sutherland, R. J. (2002). Humans with hippocampus damage display severe spatial memory impairments in a virtual Morris water task. Behavioural Brain Research, 132(1), 77-84. doi:10.1016/s0166-4328(01)00399-0Astur, R. S., Tropp, J., Sava, S., Constable, R. T., & Markus, E. J. (2004). Sex differences and correlations in a virtual Morris water task, a virtual radial arm maze, and mental rotation☆. Behavioural Brain Research, 151(1-2), 103-115. doi:10.1016/j.bbr.2003.08.024Sturz, B. R., & Bodily, K. D. (2010). Encoding of variability of landmark-based spatial information. Psychological Research, 74(6), 560-567. doi:10.1007/s00426-010-0277-4Cánovas, R., García, R. F., & Cimadevilla, J. M. (2011). Effect of reference frames and number of cues available on the spatial orientation of males and females in a virtual memory task. Behavioural Brain Research, 216(1), 116-121. doi:10.1016/j.bbr.2010.07.026Cimadevilla, J. M., Cánovas, R., Iribarne, L., Soria, A., & López, L. (2011). A virtual-based task to assess place avoidance in humans. Journal of Neuroscience Methods, 196(1), 45-50. doi:10.1016/j.jneumeth.2010.12.026Cheng, K. (1986). A purely geometric module in the rat’s spatial representation. Cognition, 23(2), 149-178. doi:10.1016/0010-0277(86)90041-7Burgess, N., Maguire, E. A., Spiers, H. J., & O’Keefe, J. (2001). A Temporoparietal and Prefrontal Network for Retrieving the Spatial Context of Lifelike Events. NeuroImage, 14(2), 439-453. doi:10.1006/nimg.2001.0806Burgess, N., Maguire, E. A., & O’Keefe, J. (2002). The Human Hippocampus and Spatial and Episodic Memory. Neuron, 35(4), 625-641. doi:10.1016/s0896-6273(02)00830-9Passolunghi, M. C., & Mammarella, I. C. (2011). Selective Spatial Working Memory Impairment in a Group of Children With Mathematics Learning Disabilities and Poor Problem-Solving Skills. Journal of Learning Disabilities, 45(4), 341-350. doi:10.1177/0022219411400746Thomas, E., Reeve, R., Fredrickson, A., & Maruff, P. (2011). Spatial memory and executive functions in children. Child Neuropsychology, 17(6), 599-615. doi:10.1080/09297049.2011.567980SPOONER, D., & PACHANA, N. (2006). Ecological validity in neuropsychological assessment: A case for greater consideration in research with neurologically intact populations. Archives of Clinical Neuropsychology, 21(4), 327-337. doi:10.1016/j.acn.2006.04.004Juan, M. C., Alcaniz, M., Monserrat, C., Botella, C., Banos, R. M., & Guerrero, B. (2005). Using Augmented Reality to Treat Phobias. IEEE Computer Graphics and Applications, 25(6), 31-37. doi:10.1109/mcg.2005.143Furió, D., González-Gancedo, S., Juan, M.-C., Seguí, I., & Costa, M. (2013). The effects of the size and weight of a mobile device on an educational game. Computers & Education, 64, 24-41. doi:10.1016/j.compedu.2012.12.015Juan MC, Furió D, Alem L, Ashworth P, Cano J (2011) ARGreenet and BasicGreenet: Two mobile games for learning how to recycle. Proceedings of the 19th International Conference on Computer Graphics, Visualization and Computer Vision. pp.25–32.Furió, D., González-Gancedo, S., Juan, M.-C., Seguí, I., & Rando, N. (2013). Evaluation of learning outcomes using an educational iPhone game vs. traditional game. Computers & Education, 64, 1-23. doi:10.1016/j.compedu.2012.12.001Albrecht, U.-V., Folta-Schoofs, K., Behrends, M., & von Jan, U. (2013). Effects of Mobile Augmented Reality Learning Compared to Textbook Learning on Medical Students: Randomized Controlled Pilot Study. Journal of Medical Internet Research, 15(8), e182. doi:10.2196/jmir.2497Liu, P.-H. E., & Tsai, M.-K. (2012). Using augmented-reality-based mobile learning material in EFL English composition: An exploratory case study. British Journal of Educational Technology, 44(1), E1-E4. doi:10.1111/j.1467-8535.2012.01302.xBaddeley AD (1986) Working memory. Oxford: Clarendon Press.Alloway TP (2012) Working Memory Assessment. Second Edi. London: Pearson Assessment.Kamphaus KW, Perez-Hernandez E, Sanchez-Sanchez F (2014) Cuestionario de Evaluación Clínica de la Memoria. In press. Madrid: TEA Ediciones.Smith, A. D., Gilchrist, I. D., & Hood, B. M. (2005). Children’s Search Behaviour in Large-Scale Space: Developmental Components of Exploration. Perception, 34(10), 1221-1229. doi:10.1068/p5270Piccardi, L., Palermo, L., Leonzi, M., Risetti, M., Zompanti, L., D’Amico, S., & Guariglia, C. (2014). The Walking Corsi Test (WalCT): A Normative Study of Topographical Working Memory in a Sample of 4- to 11-Year-Olds. The Clinical Neuropsychologist, 28(1), 84-96. doi:10.1080/13854046.2013.863976Gathercole, S. E., Pickering, S. J., Ambridge, B., & Wearing, H. (2004). The Structure of Working Memory From 4 to 15 Years of Age. Developmental Psychology, 40(2), 177-190. doi:10.1037/0012-1649.40.2.177Best, J. R., & Miller, P. H. (2010). A Developmental Perspective on Executive Function. Child Development, 81(6), 1641-1660. doi:10.1111/j.1467-8624.2010.01499.xBianchini, F., Incoccia, C., Palermo, L., Piccardi, L., Zompanti, L., Sabatini, U., … Guariglia, C. (2010). Developmental topographical disorientation in a healthy subject. Neuropsychologia, 48(6), 1563-1573. doi:10.1016/j.neuropsychologia.2010.01.025Iaria, G., & Barton, J. J. S. (2010). Developmental topographical disorientation: a newly discovered cognitive disorder. Experimental Brain Research, 206(2), 189-196. doi:10.1007/s00221-010-2256-9Lowe, P. A., Mayfield, J. W., & Reynolds, C. R. (2003). Gender differences in memory test performance among children and adolescents. Archives of Clinical Neuropsychology, 18(8), 865-878. doi:10.1093/arclin/18.8.865Barnfield, A. M. C. (1999). Development of Sex Differences in Spatial Memory. Perceptual and Motor Skills, 89(1), 339-350. doi:10.2466/pms.1999.89.1.339Alloway, T. P., Gathercole, S. E., Kirkwood, H., & Elliott, J. (2009). The working memory rating scale: A classroom-based behavioral assessment of working memory. Learning and Individual Differences, 19(2), 242-245. doi:10.1016/j.lindif.2008.10.003Injoque-Ricle, I., Calero, A. D., Alloway, T. P., & Burin, D. I. (2011). Assessing working memory in Spanish-speaking children: Automated Working Memory Assessment battery adaptation. Learning and Individual Differences, 21(1), 78-84. doi:10.1016/j.lindif.2010.09.012Jones, A., Scanlon, E., Tosunoglu, C., Morris, E., Ross, S., Butcher, P., & Greenberg, J. (1999). Contexts for evaluating educational software. Interacting with Computers, 11(5), 499-516. doi:10.1016/s0953-5438(98)00064-2Mayes, J. ., & Fowler, C. . (1999). Learning technology and usability: a framework for understanding courseware. Interacting with Computers, 11(5), 485-497. doi:10.1016/s0953-5438(98)00065-4Squires, D., & Preece, J. (1999). Predicting quality in educational software: Interacting with Computers, 11(5), 467-483. doi:10.1016/s0953-5438(98)00063-0Sun, P.-C., Tsai, R. J., Finger, G., Chen, Y.-Y., & Yeh, D. (2008). What drives a successful e-Learning? An empirical investigation of the critical factors influencing learner satisfaction. Computers & Education, 50(4), 1183-1202. doi:10.1016/j.compedu.2006.11.007Lee, S. J., Srinivasan, S., Trail, T., Lewis, D., & Lopez, S. (2011). Examining the relationship among student perception of support, course satisfaction, and learning outcomes in online learning. The Internet and Higher Education, 14(3), 158-163. doi:10.1016/j.iheduc.2011.04.001Lyons KE, Zelazo PD (2011) Monitoring, metacognition, and executive function: elucidating the role of self-reflection in the development of self-regulation. In:Benson Jeditor. Advances in Child Development and Behavior. Burlington: Academic Press. pp.379–412

MnemoCity Task: Assessment of Childrens Spatial Memory Using Stereoscopy and Virtual Environments

[EN] This paper presents the MnemoCity task, which is a 3D application that introduces the user into a totally 3D virtual environment to evaluate spatial short-term memory. A study has been carried out to validate the MnemoCity task for the assessment of spatial short-term memory in children, by comparing the children s performance in the developed task with current approaches. A total of 160 children participated in the study. The task incorporates two types of interaction: one based on standard interaction and another one based on natural interaction involving physical movement by the user. There were no statistically significant differences in the results of the task using the two types of interaction. Furthermore, statistically significant differences were not found in relation to gender. The correlations between scores were obtained using the MnemoCity task and a traditional procedure for assessing spatial short-term memory. Those results revealed that the type of interaction used did not affect the performance of children in the MnemoCity task.This work was funded mainly by the Spanish Ministry of Economy and Competitiveness (MINECO) through the CHILDMNEMOS project (TIN2012-37381-C02-01) and confinanced by the European Regional Development Fund (FEDER). Other financial support was received from the Gobierno de Aragon (Departamento de Industria e Innovacion), and Fondo Social Europeo for Aragon.Rodríguez-Andrés, D.; Juan, M.; Mendez Lopez, M.; Pérez Hernández, E.; Lluch Crespo, J. (2016). MnemoCity Task: Assessment of Childrens Spatial Memory Using Stereoscopy and Virtual Environments. PLoS ONE. 11(8):1-28. https://doi.org/10.1371/journal.pone.0161858S12811