Photobiomodulation and estrogen stabilize mitochondrial membrane potential in angiotensin–II challenged porcine aortic smooth muscle cells

Rupture of Abdominal aortic aneurysm (AAA) is among the 15 leading causes of death after age 65. Using high frequency ultrasound, we showed that photobiomodulation (PBM) prevents formation and progression of AAA in the angiotensin-II (Ang-II)-infused, apolipoprotein-e-deficient mouse model. In the current study we report that while challenge of porcine aortic Smooth Muscle Cells (SMCs) with Ang-II (1 μM) resulted in a marked decay in mitochondrial membrane potential (MitMP) vs non-challenged cells, treatment with PBM (continuous diode laser, 780 nm, 6.7 mW/cm², 5 minutes, 2 J/cm²) or pre-incubation with estrogen (50 nM, 1 hour) significantly attenuated this deterioration in MitMP. We also report that PBM and estrogen markedly affected porcine aortic SMC contraction and modified mitochondrial dispersion reflecting important influence on SMC function. These studies provide strong evidence of the important underlying role of mitochondria in the preventive effect of PBM on formation and progression of AAA and its reduced incidence and delayed onset in women.     

Dynamics of forager arrivals and nectar renewal in flowers of Anchusa strigosa

Summary Long-tongued Anthophora spp. bees collecting nectar from flowers of Anchusa strigosa (Boraginaceae) exhibit systematic foraging. Successive forager arrivals at individual flowers are not independent, and the time elapsed between successive arrivals at a particular flower is distributed more uniformly than be expected on the basis of a random arrival process. Distributions of inter-arrival time for individual flowers show standard deviation/mean ratios of 0.44–0.79, a range which is consistent with results obtained for two other plant-pollinator systems. The rate at which nectar is renewed between successive forager arrivals is independent of the amount of nectar in the flower, and the renewal process is strongly linear. Practical and theoretical implications of these results are discussed.