General phytoplasma detection by a q-PCR method using mycoplasma primers.

Phytoplasmas and mycoplasmas are bacteria belonging to the class Mollicutes. In this study, a fine tuning of quantitative polymerase chain reaction (qPCR) with a universal mycoplasma primer pair (GPO3F/MGSO) targeting the 16S rRNA gene was carried out on phytoplasmas. The dissociation curves of DNAs from Catharanthus roseus phytoplasma-infected micropropagated shoots and from phytoplasma field-infected plant samples showed a single peak at 82.5 °C (±0.5) specifically detecting phytoplasmas belonging to several ribosomal groups. Assay specificity was determined with DNA of selected bacteria: 'Candidatus Liberibacter solanacearum', Xylella fastidiosa, Ralstonia solanacearum and Clavibacter michiganensis. No amplification curves were observed with any of these tested bacteria except 'Ca. L. solanacearum' that was amplified with a melting temperature at 85 °C. Absolute quantification of phytoplasma titer was calculated using standard curves prepared from serial dilutions of plasmids containing the cloned fragment GPO3F/MGSO from European stone fruit yellows phytoplasma. Phytoplasma copy number ranged from 106 to 103 according with the sample. The sensitivity evaluated comparing plasmid serial dilutions resulted 10-6 for conventional PCR and 10-7 for qPCR. The latter method resulted therefore able to detect very low concentrations of phytoplasma in plant material.

Imbalanced social-communicative and restricted repetitive behavior subtypes of autism spectrum disorder exhibit different neural circuitry.

Social-communication (SC) and restricted repetitive behaviors (RRB) are autism diagnostic symptom domains. SC and RRB severity can markedly differ within and between individuals and may be underpinned by different neural circuitry and genetic mechanisms. Modeling SC-RRB balance could help identify how neural circuitry and genetic mechanisms map onto such phenotypic heterogeneity. Here, we developed a phenotypic stratification model that makes highly accurate (97-99%) out-of-sample SC = RRB, SC > RRB, and RRB > SC subtype predictions. Applying this model to resting state fMRI data from the EU-AIMS LEAP dataset (n = 509), we find that while the phenotypic subtypes share many commonalities in terms of intrinsic functional connectivity, they also show replicable differences within some networks compared to a typically-developing group (TD). Specifically, the somatomotor network is hypoconnected with perisylvian circuitry in SC > RRB and visual association circuitry in SC = RRB. The SC = RRB subtype show hyperconnectivity between medial motor and anterior salience circuitry. Genes that are highly expressed within these networks show a differential enrichment pattern with known autism-associated genes, indicating that such circuits are affected by differing autism-associated genomic mechanisms. These results suggest that SC-RRB imbalance subtypes share many commonalities, but also express subtle differences in functional neural circuitry and the genomic underpinnings behind such circuitry.

Parieto-frontal gradients and domains underlying eye and hand operations in the action space.

In monkeys, motor intention in its different forms emerges from a parietal-frontal gradient of visual, eye and hand signals, containing discrete dominant domains. These are formed by areas sharing cortical connections and functional properties. Within this gradient, the combination of different inputs determines the tuning properties of neurons, while local and long cortico-cortical connections shape the structure and temporal delays of the network. The pathways linking similar functional domains in parietal and frontal cortex sculpt information processing systems related to different functions, all requiring eye-hand coordination. fMRI experiments show that similar gradients lay at the core of cognitive-motor control in humans as well. This eye-hand matrix provides a framework to address, within a unitary frame, not only basic forms of motor behavior, such as reaching and grasping, but also actions of increasing complexity, such as interception of moving targets, tool use, construction of complex objects, maze analysis and solution, among others. The organization of the cerebral cortex into functional gradients and domains, beyond frontal and parietal cortices, is common to other brain regions, such as prefrontal cortex and hippocampus, and does not support views of the parieto-frontal operations based on specific and strictly segregated eye and hand modules. These can only be found at the eye and hand motor output domains in the frontal cortex, that is in the frontal eye fields and in the primary motor cortex, respectively.

Do non-human primates cooperate? Evidences of motor coordination during a joint action task in macaque monkeys.

Humans are intensively social primates, therefore many of their actions are dedicated to communication and interaction with other individuals. Despite the progress in understanding the cognitive and neural processes that allow humans to perform cooperative actions, in non-human primates only few studies have investigated the ability to interact with a partner in order to reach a common goal. These studies have shown that in naturalistic conditions animals engage in various types of social behavior that involve forms of mutual coordination and cooperation. However, little is known on the capacity of non-human primates to actively cooperate in a controlled experimental setting, which allows full characterization of the motor parameters underlying individual action and their change during motor cooperation. To this aim, we analyzed the behavior of three pairs of macaque monkeys trained to perform solo and joint-actions by exerting a force on an isometric joystick, as to move an individual or a common cursor toward visual targets on a screen. We found that during cooperation monkeys reciprocally adapt their behavior by changing the parameters that define the spatial and temporal aspects of their action, as to fine tune their joint effort, and maximize their common performance. Furthermore the results suggest that when acting together the movement parameters that specify each actor's behavior are not only modulated during execution, but also during planning. These findings provide the first quantitative description of action coordination in non-human primates during the performance of a joint action task.