The antioxidant ability of thiol compounds has been the subject of much of the current research about oxidative stress. The direct scavenging of hydroxyl radicals by thiols has been suggested as their protection mechanisms. Nevertheless, the interaction of thiols with reactive radicals can generate thiyl radicals, which, in turn, may impart a pro-oxidant function. The purpose of this study has been to establish the effect of the thiol compounds N-acetyl-L-cysteine (NAC) and glutathione (GSH) against the peroxidative processes involving membrane lipids. The results obtained support the ability of NAC and GSH to suppress the 2,2 0 -azobis-(2-amidinopropane) dihydrochloride (AAPH)-dependent or to enhance the Fe 2+ /H 2 O 2 -dependent oxidative actions. The evaluation of thiobarbituric acid reactive substances (TBARS) production, the study of the influence of oxidants on membrane fluidity and the measurements of the changes in the fluorescence of bilayer probes, such as 3-( p-(6-phenyl)-1,3,5-hexatrienyl)phenylpropionic acid (DPH-PA), have shown the antioxidant and pro-oxidant effects of both NAC and GSH. Also their dependence on the nature of the radicals generated by the oxidative systems used has been shown. The use of ESR spectroscopy has allowed us to establish the ability of these compounds to scavenge the AAPH-derived radicals, to determine the formation of thiyl radicals in the iron-mediated oxidation and to evaluate the enhanced production of hydroxyl radicals by NAC and GSH.

Recently, there have been discussions of the relative merits of passage of fishes around hydroelectric dams on three rivers (Au Sable, Manistee, and Muskegon) in Michigan. A hazard assessment was conducted to determine the potential for adverse effects on bald eagles that could consume such fishes from above and below dams on the three primary rivers. The hazard assessments were verified by comparing the reproductive productivities of eagles nesting in areas where they ate primarily fish from either above or below dams on the three primary rivers, as well as on two additional rivers in Michigan, the Menominee and Thunder Bay. Concentrations of organochlorine insecticides (OCI), polychlorinated biphenyls (total PCBs), 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ), and total mercury (Hg) were measured in composite samples of fishes from above and below hydroelectric dams on the Manistee and Muskegon Rivers, which flow into Lake Michigan, and the Au Sable River, which flows into Lake Huron. Mean concentrations of OCI, total PCBs, and TCDD-EQ were all greater in fishes from below the dams than in those from above. The hazard assessment indicated that current concentrations of Hg and OCI other than DDT (DDT+DDE+DDD) in fish from neither above nor below dams would present a significant hazard to bald eagles (Haliaeetus leucocephalus). Both total PCBs and TCDD-EQ in fishes from below the dams currently present a significant hazard to bald eagles, since their mean hazard quotients (HQ) were all greater than one.

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Reintroduction of the threatened red-crowned crane has been unsuccessful. Although gut microbiota correlates with host health, there is little information on gut microbiota of cranes under different conservation strategies. The study examined effects of captivity, artificial breeding and life stage on gut microbiota of red-crown cranes. The gut microbiotas of wild, captive adolescent, captive adult, artificially bred adolescent and artificially bred adult cranes were characterized by next-generation sequencing of 16S rRNA gene amplicons. The gut microbiotas were dominated by three phyla: Firmicutes (62.9%), Proteobacteria (29.9%) and Fusobacteria (9.6%). Bacilli dominated the ‘core’ community consisting of 198 operational taxonomic units (OTUs). Both captivity and artificial breeding influenced the structures and diversities microbiota of the gut. Especially, wild cranes had distinct compositions of gut microbiota from captive and artificially bred cranes. The greatest alpha diversity was found in captive cranes, while wild cranes had the least. According to the results of ordination analysis, influences of captivity and artificial breeding were greater than that of life stage. Overall, captivity and artificial breeding influenced the gut microbiota, potentially due to changes in diet, vaccination, antibiotics and living conditions. Metagenomics can serve as a supplementary non-invasive screening tool for disease control.

Photodynamic therapy (PDT) requires photosensitizer, light, and oxygen to induce cell death. The majority of efforts to advance PDT focus only on the first two components. Here, we employ perfluorocarbon nanoemulsions to simultaneously deliver oxygen and photosensitizer. We find that the implementation of fluorous soluble photosensitizers enhances the efficacy of PDT. Phototherapeutics are emerging avenues to mitigate side-effects of treatments due to the spatiotemporal control that can be achieved with light. 1 Photodynamic therapy (PDT), a classic phototherapeutic, employs a photosensitizer to generate reactive oxygen species (ROS) that induce local cell death (Figure 1A). 1 Current clinical uses of PDT include treatment of actinic keratosis, small cell carcinoma, pleural mesothelioma, oesophageal, non-small cell lung and skin cancer with other applications on the horizon as new photosensitizers and endoscopic technologies are developed. 2 Photosensitizer optimization and expanding the scope of tissue that can be irradiated with light contribute to the majority of advancements in PDT. 3 These are critical components; however, the direct therapeutic effect of PDT is a result of ROS such as singlet oxygen (1 O 2). 4 Hypoxia is a hallmark of many tumors 5 and limits the amount of ROS that can be generated even if ample light and photosensitizer are present. The ideal therapeutic for PDT is one that simultaneously delivers oxygen and photosensitizer to the disease site. Perfluorocarbon (PFC) nanoemulsions, droplets of fluorous solvent stabilized by a surfactant, are a compelling platform for PDT owing to the high oxygen content in perfluorocarbons (Figure 1B). 6 Previously, we have shown that fluorophores can be localized inside PFC nanoemulsions when fluorous chains are appended to the chromophore scaffold. 7 We imagined that a similar strategy could be employed to load PFC nanoemulsions with a photosensitizer to result in an exceptional nanomaterial for PDT (Figure 1C). Efforts to enhance PDT with perfluorocarbons began in 1988 when Henderson and co-workers co-injected a porphyrin photosensitizer with PFC nanoemulsions. 8 Despite promising results, this approach remained dormant for 25 years until cyanine dyes were embedded into the surfactant layer of PFC nanoemulsions to facilitate dual oxygen and photosensitizer delivery. 9 Contemporary variants of co-administration of photosensitizer and PFC nanoemulsions have also been pursued. 10 Figure 1. (A) Photodynamic therapy (PDT) involves the introduction of a photosensitizer which generates reactive oxygen species (ROS) upon irradiation with light to result in cell death. (B) Perfluorocarbon (PFC) nanoemulsions are droplets of fluorous solvent stabilized with surfactant. They have high oxygen content. (C) One step formulation of PFC nanoemulsions for PDT. Collectively, these reports demonstrate the potential of PFC nanoemulsions for PDT. However, organic photosensitizers are not compatible with the fluorous solvent, which can lead to inefficient photosensitization ...