Study on effects of physical, biological and chemical parameters on growth and bloom-forming of dinoflagellates Cochlodinium polykrikoides

The red tide, as a natural phenomenon, has been frequently occurred in the Persian Gulf and Oman Sea coastal waters. Harmful algal blooms of Cochlodinium polykricoiedes were first observed in August 2007 and coincided with massive aquatic organisms’ mortalities and have caused substantial economic losses and negative effects on the aquatic environment in the Persian Gulf. The objective of this study was to evaluate direct control or mitigation of C. polykricoiedes blooms through physical (flocculation with clay; 0.5, 1.0, 1.5, 2, 4 and 10 g L^-1), biological [6 seaweeds; fresh and extract (aqueous and methanol)] and chemical (hydrogen peroxide, potassium permanganate, copper sulfate, acetic acid and sodium hypochlorite; 0.05, 0.1, 0.5, 1 and 1.5 g L^-1) treatments. The results of the physical assay showed that the growth of C. polykricoiedes was strongly inhibited by using clay slurry in 4 or 10 g L^-1. The removal efficiency of C. polykricoiedes by clay was 99% after 24 hour. The seaweeds showed the most mitigation effect on C. polykricoiedes using aqueous extract was C. sinnosa, using mixed aqueous and methanol were S. illicifolium , U. lactuca and G. corticata, fresh tissue were E.intistialis، C.sinuosa, H.valentiea, and culture filtrate of E. intistialis. The results clearly showed that the flocculants; potassium permanganate, copper sulfate, acetic acid and sodium hypochlorite had the highest removal efficiency (100%) of C. polykricoiedes cells in the lowest concentration (0.05 g L^-1). Overall, our experiments suggest that using clay and seaweeds as a control strategies could be considered for HABs in the Persian Gulf coastal waters

Depletion and activation of microglia impact metabolic connectivity of the mouse brain

AimWe aimed to investigate the impact of microglial activity and microglial FDG uptake on metabolic connectivity, since microglial activation states determine FDG-PET alterations. Metabolic connectivity refers to a concept of interacting metabolic brain regions and receives growing interest in approaching complex cerebral metabolic networks in neurodegenerative diseases. However, underlying sources of metabolic connectivity remain to be elucidated.Materials and methodsWe analyzed metabolic networks measured by interregional correlation coefficients (ICCs) of FDG-PET scans in WT mice and in mice with mutations in progranulin (Grn) or triggering receptor expressed on myeloid cells 2 (Trem2) knockouts ((-/-)) as well as in double mutant Grn(-/-)/Trem2(-/-) mice. We selected those rodent models as they represent opposite microglial signatures with disease associated microglia in Grn(-/-) mice and microglia locked in a homeostatic state in Trem2(-/-) mice;however, both resulting in lower glucose uptake of the brain. The direct influence of microglia on metabolic networks was further determined by microglia depletion using a CSF1R inhibitor in WT mice at two different ages. Within maps of global mean scaled regional FDG uptake, 24 pre-established volumes of interest were applied and assigned to either cortical or subcortical networks. ICCs of all region pairs were calculated and z-transformed prior to group comparisons. FDG uptake of neurons, microglia, and astrocytes was determined in Grn(-/-) and WT mice via assessment of single cell tracer uptake (scRadiotracing).ResultsMicroglia depletion by CSF1R inhibition resulted in a strong decrease of metabolic connectivity defined by decrease of mean cortical ICCs in WT mice at both ages studied (6-7 m;p = 0.0148, 9-10 m;p = 0.0191), when compared to vehicle-treated age-matched WT mice. Grn(-/-), Trem2(-/-) and Grn(-/-)/Trem2(-/-) mice all displayed reduced FDG-PET signals when compared to WT mice. However, when analyzing metabolic networks, a distinct increase of ICCs was observed in Grn(-/-) mice when compared to WT mice in cortical (p < 0.0001) and hippocampal (p < 0.0001) networks. In contrast, Trem2(-/-) mice did not show significant alterations in metabolic connectivity when compared to WT. Furthermore, the increased metabolic connectivity in Grn(-/-) mice was completely suppressed in Grn(-/-)/Trem2(-/-) mice. Grn(-/-) mice exhibited a severe loss of neuronal FDG uptake (- 61%, p < 0.0001) which shifted allocation of cellular brain FDG uptake to microglia (42% in Grn(-/-) vs. 22% in WT).ConclusionsPresence, absence, and activation of microglia have a strong impact on metabolic connectivity of the mouse brain. Enhanced metabolic connectivity is associated with increased microglial FDG allocation

Polygenic burden associated to oligodendrocyte precursor cells and radial glia influences the hippocampal volume changes induced by aerobic exercise in schizophrenia patients

Hippocampal volume decrease is a structural hallmark of schizophrenia (SCZ), and convergent evidence from postmortem and imaging studies suggests that it may be explained by changes in the cytoarchitecture of the cornu ammonis 4 (CA4) and dentate gyrus (DG) subfields. Increasing evidence indicates that aerobic exercise increases hippocampal volume in CA subfields and improves cognition in SCZ patients. Previous studies showed that the effects of exercise on the hippocampus might be connected to the polygenic burden of SCZ risk variants. However, little is known about cell type-specific genetic contributions to these structural changes. In this secondary analysis, we evaluated the modulatory role of cell type-specific SCZ polygenic risk scores (PRS) on volume changes in the CA1, CA2/3, and CA4/DG subfields over time. We studied 20 multi-episode SCZ patients and 23 healthy controls who performed aerobic exercise, and 21 multi-episode SCZ patients allocated to a control intervention (table soccer) for 3 months. Magnetic resonance imaging-based assessments were performed with FreeSurfer at baseline and after 3 months. The analyses showed that the polygenic burden associated with oligodendrocyte precursor cells (OPC) and radial glia (RG) significantly influenced the volume changes between baseline and 3 months in the CA4/DG subfield in SCZ patients performing aerobic exercise. A higher OPC- or RG-associated genetic risk burden was associated with a less pronounced volume increase or even a decrease in CA4/DG during the exercise intervention. We hypothesize that SCZ cell type-specific polygenic risk modulates the aerobic exercise-induced neuroplastic processes in the hippocampus