Selective modulation of chemical and electrical synapses of Helix neuronal networks during in vitro development

BACKGROUND: A large number of invertebrate models, including the snail Helix, emerged as particularly suitable tools for investigating the formation of synapses and the specificity of neuronal connectivity. Helix neurons can be individually identified and isolated in cell culture, showing well-conserved size, position, biophysical properties, synaptic connections, and physiological functions. Although we previously showed the potential usefulness of Helix polysynaptic circuits, a full characterization of synaptic connectivity and its dynamics during network development has not been performed. RESULTS: In this paper, we systematically investigated the in vitro formation of polysynaptic circuits, among Helix B2 and the serotonergic C1 neurons, from a morphological and functional point of view. Since these cells are generally silent in culture, networks were chemically stimulated with either high extracellular potassium concentrations or, alternatively, serotonin. Potassium induced a transient depolarization of all neurons. On the other hand, we found prolonged firing activity, selectively maintained following the first serotonin application. Statistical analysis revealed no significant changes in neuronal dynamics during network development. Moreover, we demonstrated that the cell-selective effect of serotonin was also responsible for short-lasting alterations in C1 excitability, without long-term rebounds. Estimation of the functional connections by means of cross-correlation analysis revealed that networks under elevated KCl concentrations exhibited strongly correlated signals with short latencies (about 5 ms), typical of electrically coupled cells. Conversely, neurons treated with serotonin were weakly connected with longer latencies (exceeding 20 ms) between the interacting neurons. Finally, we clearly demonstrated that these two types of correlations (in terms of strength/latency) were effectively related to the presence of electrical or chemical connections, by comparing Micro-Electrode Array (MEA) signal traces with intracellularly recorded cell pairs. CONCLUSIONS: Networks treated with either potassium or serotonin were predominantly interconnected through electrical or chemical connections, respectively. Furthermore, B2 response and short-term increase in C1 excitability induced by serotonin is sufficient to trigger spontaneous activity with chemical connections, an important requisite for long-term maintenance of firing activity

Photographic database of the European cave salamanders, genus Hydromantes

European Hydromantes are a group of eight salamander species often occurring in subterranean habitats, which are a difficult environment to explore. All Hydromantes are strictly protected species and thus, low-impact methodologies to study these salamanders are strongly needed. Here we used a photographic technique to produce a large dataset of European Hydromantes, providing standardised pictures of 1,052 individuals belonging to the eight species, including hybrids as well. With our methodology we were able to reduce the handling time of individuals, and produce high quality pictures useful to investigate multiple life traits of these endangered species. Furthermore, the standardised photos provided here can be used for future comparisons of individuals from the surveyed populations

High flavonoid accompanied with high starch accumulation triggered by nutrient starvation in bioenergy crop duckweed (Landoltia punctata)

Background: As the fastest growing plant, duckweed can thrive on anthropogenic wastewater. The purple-backed duckweed, Landoltia punctata, is rich in starch and flavonoids. However, the molecular biological basis of high flavonoid and low lignin content remains largely unknown, as does the best method to combine nutrients removed from sewage and the utilization value improvement of duckweed biomass. Results: A combined omics study was performed to investigate the biosynthesis of flavonoid and the metabolic flux changes in L. punctata grown in different culture medium. Phenylalanine metabolism related transcripts were identified and carefully analyzed. Expression quantification results showed that most of the flavonoid biosynthetic transcripts were relatively highly expressed, while most lignin-related transcripts were poorly expressed or failed to be detected by iTRAQ based proteomic analyses. This explains why duckweed has a much lower lignin percentage and higher flavonoid content than most other plants. Growing in distilled water, expression of most flavonoid-related transcripts were increased, while most were decreased in uniconazole treated L. punctata (1/6 x Hoagland + 800 mg center dot L-1 uniconazole). When L. punctata was cultivated in full nutrient medium (1/6 x Hoagland), more than half of these transcripts were increased, however others were suppressed. Metabolome results showed that a total of 20 flavonoid compounds were separated by HPLC in L. punctata grown in uniconazole and full nutrient medium. The quantities of all 20 compounds were decreased by uniconazole, while 11 were increased and 6 decreased when grown in full nutrient medium. Nutrient starvation resulted in an obvious purple accumulation on the underside of each frond. Conclusions: The high flavonoid and low lignin content of L. punctata appears to be predominantly caused by the flavonoid-directed metabolic flux. Nutrient starvation is the best option to obtain high starch and flavonoid accumulation simultaneously in a short time for biofuels fermentation and natural products isolation

Reactive oxygen species regulate activity-dependent neuronal plasticity in Drosophila.

Reactive oxygen species (ROS) have been extensively studied as damaging agents associated with ageing and neurodegenerative conditions. Their role in the nervous system under non-pathological conditions has remained poorly understood. Working with the Drosophila larval locomotor network, we show that in neurons ROS act as obligate signals required for neuronal activity-dependent structural plasticity, of both pre- and postsynaptic terminals. ROS signaling is also necessary for maintaining evoked synaptic transmission at the neuromuscular junction, and for activity-regulated homeostatic adjustment of motor network output, as measured by larval crawling behavior. We identified the highly conserved Parkinson's disease-linked protein DJ-1β as a redox sensor in neurons where it regulates structural plasticity, in part via modulation of the PTEN-PI3Kinase pathway. This study provides a new conceptual framework of neuronal ROS as second messengers required for neuronal plasticity and for network tuning, whose dysregulation in the ageing brain and under neurodegenerative conditions may contribute to synaptic dysfunction.This work was supported by BBSRC research grants (BB/IO1179X/1, BB/M002934/1) to ML, (BB/I012273/1, BB/M002322/1) to STS and (BB/N/014561/1) to RAB

Addressing Cancer Disparities via Community Network Mobilization and Intersectoral Partnerships: A Social Network Analysis

Community mobilization and collaboration among diverse partners are vital components of the effort to reduce and eliminate cancer disparities in the United States. We studied the development and impact of intersectoral connections among the members of the Massachusetts Community Network for Cancer Education, Research, and Training (MassCONECT). As one of the Community Network Program sites funded by the National Cancer Institute, this infrastructure-building initiative utilized principles of Community-based Participatory Research (CBPR) to unite community coalitions, researchers, policymakers, and other important stakeholders to address cancer disparities in three Massachusetts communities: Boston, Lawrence, and Worcester. We conducted a cross-sectional, sociometric network analysis four years after the network was formed. A total of 38 of 55 members participated in the study (69% response rate). Over four years of collaboration, the number of intersectoral connections reported by members (intersectoral out-degree) increased, as did the extent to which such connections were reported reciprocally (intersectoral reciprocity). We assessed relationships between these markers of intersectoral collaboration and three intermediate outcomes in the effort to reduce and eliminate cancer disparities: delivery of community activities, policy engagement, and grants/publications. We found a positive and statistically significant relationship between intersectoral out-degree and community activities and policy engagement (the relationship was borderline significant for grants/publications). We found a positive and statistically significant relationship between intersectoral reciprocity and community activities and grants/publications (the relationship was borderline significant for policy engagement). The study suggests that intersectoral connections may be important drivers of diverse intermediate outcomes in the effort to reduce and eliminate cancer disparities. The findings support investment in infrastructure-building and intersectoral mobilization in addressing disparities and highlight the benefits of using CBPR approaches for such work

The post hoc measurement as a safe and reliable method to age and size plethodontid salamanders

The worldwide biodiversity crisis with the resulting need to increase species protection has led researchers to pursue and select survey methods that guarantee the best quality of data and produce the least negative effects on wild animals. Plethodontids are the most diverse family of salamanders; all species are very sensitive to human handling and noninvasive, but accurate, measurement methods are needed to reduce researchers\u2019 impact. Here, we tested the reliability of a noninvasive post hoc method in estimating the snout\u2013vent length (SVL) from photographs showing salamanders\u2019 dorsal view. The correlation between the estimated snout\u2013vent length (SVLe) and the conventional SVL was high (R2m =.81), and no significant difference occurred between operators with different experience. Finally, we list the numerous advantages for the use of SVLe in terms of data quality and in reducing the stress caused to wild animals

Cryptochrome-dependent magnetic field effect on seizure response in Drosophila larvae

The mechanisms that facilitate animal magnetoreception have both fascinated and confounded scientists for decades, and its precise biophysical origin remains unclear. Among the proposed primary magnetic sensors is the flavoprotein, cryptochrome, which is thought to provide geomagnetic information via a quantum effect in a light-initiated radical pair reaction. Despite recent advances in the radical pair model of magnetoreception from theoretical, molecular and animal behaviour studies, very little is known of a possible signal transduction mechanism. We report a substantial effect of magnetic field exposure on seizure response in Drosophila larvae. The effect is dependent on cryptochrome, the presence and wavelength of light and is blocked by prior ingestion of typical antiepileptic drugs. These data are consistent with a magnetically-sensitive, photochemical radical pair reaction in cryptochrome that alters levels of neuronal excitation, and represent a vital step forward in our understanding of the signal transduction mechanism involved in animal magnetoreception

Ambulation three hours after elective cardiac catheterisation through the femoral artery.

OBJECTIVE: To test whether very early resumption of ambulation after femoral cardiac catheterisation is feasible and safe in patients with stable symptoms. DESIGN: Prospective study in a selected group of men and women undergoing elective cardiac catheterisation, with next day physical inspection. SETTING: Inpatient study. SUBJECTS: Two hundred consecutive ambulant patients submitted to diagnostic cardiac catheterisation through the femoral arterial route using 5F catheters: a femoral right heart study was done at the same time in 40 patients (20%). RESULTS: No patient had major complications during the study. Early ambulation was not allowed in two patients (1%) because of haematoma formation immediately after sheath removal, and in seven (3%) because of poor haemostasis or haematoma on inspection at 3 h. Early ambulation was interrupted in two patients (1%) because of transient arterial hypotension on standing in one, and the patient's preference in the other. Of 189 patients who resumed full ambulation at 3 h, one (0.5%) had a groin haematoma on discharge the next morning. Overall, haematoma 12 h after cardiac catheterisation was present in seven of the 200 patients initially included in the study (3.5%). None of the 191 patients with attempted early mobilisation had signs or symptoms of vascular complications one month or later after discharge. CONCLUSION: Supervised resumption of ambulation 3 h after uncomplicated cardiac studies with 5F femoral arterial catheters is safe and feasible in most ambulant patients undergoing elective cardiac catheterisation