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Microglia contribute to the outcomes of various pathological conditions including Parkinson's disease (PD). Microglia are heterogenous, with a variety of states recently identified in aging and neurodegenerative disease models. Here, we delved into the diversity of microglia in a preclinical PD model featuring the G2019S mutation in LRRK2, a known pathological mutation associated with PD. Specifically, we investigated the ‘dark microglia’ (DM) and the ‘disease-associated microglia’ (DAM) which present a selective enrichment of CLEC7A expression. In the dorsal striatum - a region affected by PD pathology - extensive ultrastructural features of cellular stress as well as reduced direct cellular contacts, were observed for microglia from old LRRK2 G2019S mice versus controls. In addition, DM were more prevalent while CLEC7A-positive microglia had extensive phagocytic ultrastructural characteristics in the LRRK2 G2019S mice. Furthermore, our findings revealed a higher proportion of DM in LRRK2 G2019S mice, and an increased number of CLEC7A-positive cells with age, exacerbated by the pathological mutation. These CLEC7A-positive cells exhibited a selective enrichment of ameboid morphology and tended to cluster in the affected animals. In summary, we provide novel insights into the occurrence and features of recently defined microglial states, CLEC7A-positive cells and DM, in the context of LRRK2 G2019S PD pathology.

Autism spectrum disorder (ASD) is a neurodevelopmental condition often associated with mitochondrial dysfunction, including increased mitochondrial DNA (mtDNA) copy number and impaired energy production. This study investigates the role of the mitochondrial replisome-specifically, the genes TFAM, TWNK, POLG, and TOP1MT-in mtDNA replication and its potential contribution to ASD pathophysiology. We analyzed samples from the oral mucosa of children with ASD and typically developing (TD) controls, assessing mtDNA copy number, gene expression, and protein levels. Our findings revealed a significant increase in mtDNA copy number in the oral mucosa of ASD children, along with partially deleted mtDNA molecules. However, there were no significant changes in the expression of TFAM, TWNK, POLG, or MT-TL1 genes between ASD and TD samples. Additionally, TFAM protein levels, including monomeric, dimeric, and trimeric forms, did not differ significantly. We also observed increased oxidative stress and inflammatory markers in the oral mucosa of ASD children, suggesting that mitochondrial alterations may be linked to inflammation and oxidative damage in ASD. To further investigate the functional impact of TFAM, we overexpressed it in human HEK293 cells and cortical neurons (CN1.4). TFAM overexpression led to increased mtDNA copy number, cell proliferation, and ATP production in HEK293 cells, but did not significantly alter mitochondrial gene expression, protein oxidation, or mtDNA integrity. In CN1.4 neurons, TFAM overexpression increased mitochondrial membrane potential and length, indicating potential changes in mitochondrial dynamics. Overall, our study suggests that while mtDNA alterations are present in ASD, they are not directly driven by changes in mitochondrial replisome gene expression. These findings highlight the complexity of mitochondrial dysfunction in ASD and suggest the need for further investigation into the underlying molecular mechanisms., (© 2024 International Society for Autism Research and Wiley Periodicals LLC.)

Microglia contribute to the outcomes of various pathological conditions including Parkinson's disease (PD). Microglia are heterogenous, with a variety of states recently identified in aging and neurodegenerative disease models. Here, we delved into the diversity of microglia in a preclinical PD model featuring the G2019S mutation in LRRK2, a known pathological mutation associated with PD. Specifically, we investigated the 'dark microglia' (DM) and the 'disease-associated microglia' (DAM) which present a selective enrichment of CLEC7A expression. In the dorsal striatum - a region affected by PD pathology - extensive ultrastructural features of cellular stress as well as reduced direct cellular contacts, were observed for microglia from old LRRK2 G2019S mice versus controls. In addition, DM were more prevalent while CLEC7A-positive microglia had extensive phagocytic ultrastructural characteristics in the LRRK2 G2019S mice. Furthermore, our findings revealed a higher proportion of DM in LRRK2 G2019S mice, and an increased number of CLEC7A-positive cells with age, exacerbated by the pathological mutation. These CLEC7A-positive cells exhibited a selective enrichment of ameboid morphology and tended to cluster in the affected animals. In summary, we provide novel insights into the occurrence and features of recently defined microglial states, CLEC7A-positive cells and DM, in the context of LRRK2 G2019S PD pathology., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Humpback whale song chorusing dominates the marine soundscape in Hawai'i during winter months, yet little is known about spatio-temporal habitat use patterns of singers. We analysed passive acoustic monitoring data from five sites off Maui and found that ambient noise levels associated with song chorusing decreased during daytime hours nearshore but increased offshore. To resolve whether these changes reflect a diel offshore-onshore movement or a temporal difference in singing activity, data from 71 concurrently conducted land-based theodolite surveys were analysed. Non-calf pods ( n = 3082), presumably including the majority of singers, were found further offshore with increasing time of the day. Separately, we acoustically localized 217 nearshore singers using vector-sensors. During the day, distances to shore and minimum distances among singers increased, and singers switched more between being stationary and singing while travelling. Together, these findings suggest that the observed diel trends in humpback whale chorusing off Maui represent a pattern of active onshore-offshore movement of singers. We hypothesize that this may result from singers attempting to reduce intraspecific acoustic masking when densities are high nearshore and avoidance of a loud, non-humpback, biological evening chorus offshore, creating a dynamic of movement of singers aimed at increasing the efficiency of their acoustic display., Competing Interests: We declare we have no competing interests., (© 2024 The Authors.)

This research analyzes for the first time in the Pacific Tropical-Subtropical Convergence off Mexico during June 2010 the relationships among the δ 13 C and δ 15 N signal distribution in the bulk zooplankton, water masses, and mesoscale structures. The environmental analysis showed that the California Current Water (CCW) and Transitional Water (TrW) converge where the 22 °C isotherm and 34.6 g kg -1 isohaline were observed (22°N). Two cyclonic eddies were detected: one in CCW at 24°N about 70 km in diameter, the other one located in TrW at 21°N with 150 km in diameter. A cluster analysis defined three zooplankton isoscapes with significant differences. Isoscape 1, immerses in CCW - the lowest δ 13 C (-22.37 ± 0.89 ‰) and δ 15 N (9.89 ± 1.32 ‰) - showed temperature (19.86 ± 1.97 °C), salinity (34.08 ± 0.37 g kg -1 ) values, the deepest thermocline (77.93 ± 25.51 m) and oxygen minimum zone (164.78 ± 44.96 m). The CCW was relatively oligotrophic without important mesoscale features in the sampled time within the sampled area. Isoscape 2, a cyclonic eddy in CCW - relatively enriched zooplankton δ 13 C values (-16.78 ± 1.95 ‰) due to the entry of enriched coastal biota- reflected in high chlorophyll a and subsequently assimilated into zooplankton tissues. Isoscape 3, a cyclonic eddy immerses in TrW - the highest δ 15 N (13.14 ± 1.60 ‰), salinity (34.76 ± 0.19 g kg -1 ) and temperature (19.90 ± 2.27 °C) values and shallowest thermocline (32.27 ± 18.63 m), and oxygen minimum zone (66.82 ± 37.68 m) in depth. Likely, this 15 N-enriched recycled nitrate was pumped from the deoxygenated subsurface to the surface, reflected in the zooplankton bulks. The results showed that the isotopic signals in bulk zooplankton may be a good water mass and mesoscale activity tracer., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)