[Resting state-EEG connectivity and machine learning: towards improved treatment response predictions in psychiatry]. / Innovatieve eeg-analyse voor voorspelling van behandelrespons in de psychiatrie.

BACKGROUND: Innovations in the analysis of resting-state EEG focused on connectivity and network organization, combined with machine learning, offer new opportunities for treatment response predictions in psychiatry. AIM: Introduction of analysis methods in this emerging field, description of some promising results, and critical consideration of possibilities and challenges for implementation in clinical practice. METHOD: Narrative review of the literature. RESULTS: EEG connectivity and network properties may contain predictive information for treatment response to pharmacological interventions, neurostimulation, and psychotherapeutic treatments. However, the results are currently based on studies with small sample sizes and limited validation in independent datasets. Factors such as placebo effects, natural course and treatment adherence during therapy necessitate a cautious interpretation of promising results. CONCLUSION: Independent replication studies and research on implementation are needed to determine whether developed algorithms that predict treatment outcomes based on EEG recordings are of value in clinical practice.

Haloalkane-utilizing Rhodococcus strains isolated from geographically distinct locations possess a highly conserved gene cluster encoding haloalkane catabolism.

The sequences of the 16S rRNA and haloalkane dehalogenase (dhaA) genes of five gram-positive haloalkane-utilizing bacteria isolated from contaminated sites in Europe, Japan, and the United States and of the archetypal haloalkane-degrading bacterium Rhodococcus sp. strain NCIMB13064 were compared. The 16S rRNA gene sequences showed less than 1% sequence divergence, and all haloalkane degraders clearly belonged to the genus Rhodococcus. All strains shared a completely conserved dhaA gene, suggesting that the dhaA genes were recently derived from a common ancestor. The genetic organization of the dhaA gene region in each of the haloalkane degraders was examined by hybridization analysis and DNA sequencing. Three different groups could be defined on the basis of the extent of the conserved dhaA segment. The minimal structure present in all strains consisted of a conserved region of 12.5 kb, which included the haloalkane-degradative gene cluster that was previously found in strain NCIMB13064. Plasmids of different sizes were found in all strains. Southern hybridization analysis with a dhaA gene probe suggested that all haloalkane degraders carry the dhaA gene region both on the chromosome and on a plasmid (70 to 100 kb). This suggests that an ancestral plasmid was transferred between these Rhodococcus strains and subsequently has undergone insertions or deletions. In addition, transposition events and/or plasmid integration may be responsible for positioning the dhaA gene region on the chromosome. The data suggest that the haloalkane dehalogenase gene regions of these gram-positive haloalkane-utilizing bacteria are composed of a single catabolic gene cluster that was recently distributed worldwide.

Interactions of uptake of malate and nitrate into isolated vacuoles from lettuce leaves.

Vacuoles were isolated from leaves of two lettuce (Lactuca sativa L.) genotypes that differed significantly in their nitrate accumulation. The rate of nitrate uptake into the vacuoles did not differ between the genotypes, but the malate-uptake rate did. Fitting a Michaelis-Menten equation, with or without the addition of a linear term, showed that the rates of malate and nitrate uptake can be best described by saturation kinetics for both genotypes. Malate transport across the tonoplast showed a Km value of approx. 40 mM, while the Km value for nitrate uptake was approx. 5 mM. Both malate and nitrate uptake were greatly stimulated by ATP, but not by pyrophosphate. Valinomycin considerably blocked both malate and nitrate uptake while nigericin only slightly affected the rate of malate uptake and had no effect on the nitrate-uptake rate. This indicates that both nitrate and malate transport are driven by the membrane potential, while the pH gradient may play a minor role in malate transport only. The presence of nitrate in the incubation medium inhibited malate uptake (2 mM nitrate caused an inhibition of approx. 50%). In contrast to this, the presence of malate in the incubation medium did not inhibit nitrate uptake. Endogenous nitrate did not affect malate uptake. Thus, we did not find genotypic differences in the uptake pattern which could explain the variation in nitrate accumulation. The possible reason for differences in nitrate accumulation in vivo is discussed.

Direct isolation of vacuoles from leaf tissue of lettuce (Lactuca sativa) retaining protoplasts within the leaves.

A procedure is described in which vacuoles are isolated from leaf tissue of lettuce (Lactuca sativa L.). After incubation in an enzyme solution, the vacuoles are directly extracted from the leaf tissue by osmotic shock using a phosphate buffer. In this method no protoplasts are released from the leaf tissue. This procedure avoids the problems of separating vacuoles from protoplasts with similar density. To evaluate the purity of the vacuoles, the activity of glucan synthetase 11 (EC 2.4.1.34), NAD(P) H-cytochrome c reductase (EC 1.6.99.3) and malate dehydrogenase (EC 1.1.1.37) was measured. To measure vanadate- and nitrate-sensitive ATPase activity (EC 3.6.1.8) vesicles were prepared from the vacuoles and ATP-dependent vesicle acidification was measured as acridine orange quenching. Nitrate inhibited the quenching, while addition of vanadate had no effect. It was concluded that the vacuoles were not contaminated with plasma membranes. To evaluate the viability of the vacuoles [(14) C]-malate uptake was measured. The vacuoles showed a constant rate of [(14) C]-malate uptake during 45 min. This rate was maximal at pH 6.8.