Oxidative stress in Microcystis aeruginosa as a consequence of global climate change

Cyanobacteria are phototrophic organisms with great ecological and economical importance.Species of the genus Microcystis are known for their potential ability to synthesize toxins, notably microcystins.There is a growing interest in the evaluation of oxidative stress in relation to the impact of global climate change on natural ecosystems in different trophic levels. Several studies have focused on the analysis of organismal responses to mitigate the damage by controlling the generation of reactive oxygen species. Variations in environmentalfactors caused by climate change generate a situation of oxidative damage in Microcystis aeruginosa as a direct or indirect consequence. In this study we evaluate the effects of ultraviolet radiation and temperature on physiological and biochemical responses of a native M. aeruginosa (strain CAAT 2005-3). The results from the exposure to ultraviolet radiation doses and temperature changes suggest a high ability of M. aeruginosa to detect a potential stress situation as a consequence of reactive species production and to rapidly initiate antioxidant defenses. Increased catalase activity is an antioxidant protection mechanism in M. aeruginosa for short and long term exposure to different changes in environmental conditions. However, we found a ultraviolet-B radiation threshold dose above which oxidative stress exceeds the antioxidant protection and damage occurs. In additionour results are in agreement with recent findings suggesting that microcystins may act as protein-modulating metabolites and protection against reactive oxygen species.It is concluded that cyanobacteria have adaptative mechanisms that could lead to the replacement of species highly susceptible to oxidative stress by others with a higher system of antioxidant protection.Facultad de Ciencias Exacta

Leveraging PET to image folate receptor α therapy of an antibody-drug conjugate

Background: The folate receptor α (FRα)-targeting antibody-drug conjugate (ADC), IMGN853, shows great antitumor activity against FRα-expressing tumors in vivo, but patient selection and consequently therapy outcome are based on immunohistochemistry. The aim of this study is to develop an antibody-derived immuno-PET imaging agent strategy for targeting FRα in ovarian cancer as a predictor of treatment success. Methods: We developed [89Zr]Zr-DFO-M9346A, a humanized antibody-based radiotracer targeting tumorassociated FRα in the preclinical setting. [89Zr]Zr-DFO-M9346A’s binding ability was tested in an in vitro uptake assay using cell lines with varying FRα expression levels. The diagnostic potential of [89Zr]Zr-M9346A was evaluated in KB and OV90 subcutaneous xenografts. Following intravenous injection of [89Zr]Zr-DFO-M9346A (~90 μCi, 50 μg), PET imaging and biodistribution studies were performed. We determined the blood half-life of [89Zr]Zr-DFO-M9346A and compared it to the therapeutic, radioiodinated ADC [131I]-IMGN853. Finally, in vivo studies using IMG853 as a therapeutic, paired with [89Zr]Zr-DFO-M9346A as a companion diagnostic were performed using OV90 xenografts. Results: DFO-M9346A was labeled with Zr-89 at 37 °C within 60 min and isolated in labeling yields of 85.7 ± 5.7%, radiochemical purities of 98.0 ± 0.7%, and specific activities of 3.08 ± 0.43 mCi/mg. We observed high specificity for binding FRα positive cells in vitro. For PET and biodistribution studies, [89Zr]Zr-M9346A displayed remarkable in vivo performance in terms of excellent tumor uptake for KB and OV xenografts (45.8 ± 29.0 %IA/g and 26.1 ± 7.2 %IA/g), with low non-target tissue uptake in other organs such as kidneys (4.5 ± 1.2 %IA/g and 4.3 ± 0.7 %IA/g). A direct comparison of the blood half life of [89Zr]Zr-M9346A and [131I]-IMGN853 corroborated the equivalency of the radiopharmaceutical and the ADC, paving the way for a companion PET imaging study. Conclusions: We developed a new folate receptor-targeted 89Zr-labeled PET imaging agent with excellent pharmacokinetics in vivo. Good tumor uptake in subcutaneous KB and OV90 xenografts were obtained, and ADC therapy studies were performed with the precision predictor

Social capital and pet ownership – A tale of four cities☆

Highlights • Pet ownership is significantly associated with higher levels of social capital. • Social capital was associated with pet ownership in the U.S. and Australia. • Results are not confined to dog owners nor dog walkers. • Pets are an under-recognized conduit for building social capital

The Grizzly, October 13, 1992

Homecoming 1992 • A Question of Queens • U.C.\u27s Past Meets its Present • AFAC Dampens Coffee House Plans • U.C. Alum to Speak on Venusian Voyage • Philadelphia Renaissance Wind Band to Perform at Ursinus • Conversations with The Dead • Photographs From Total Silence • Movie Reviews: Singles; Bob Roberts • Cafferty Band Tickets on Sale • Jam Sessions Sparked By Chartreuse Walrus • TV or no TV • Question the Pain and Suffering • Letters to the Editor • Dean Kane on Homecoming • Field Hockey Has Up-and-Down Week • Arroliga Wins McIntyre Award • V-Ballers Beat All Opponents • Football Falls in Final Seconds • Soccer Wins Two Straighthttps://digitalcommons.ursinus.edu/grizzlynews/1301/thumbnail.jp

Physiological responses and toxin production of Microcystis aeruginosa in short-term exposure to solar UV radiation

The aim of this study was to evaluate the effects of short-term (hours) exposure to solar UV radiation (UVR, 280-400 nm) on the physiology of Microcystis aeruginosa. Three solar radiation treatments were implemented: (i) PAR (PAR, 400-700 nm), (ii) TUVA (PAR + UVAR, 315-700 nm) and (iii) TUVR (PAR + UVAR + UVBR, 280-700 nm). Differential responses of antioxidant enzymes and the reactive oxygen species (ROS) production to UVR were observed. Antioxidant enzymes were more active at high UVR doses. However, different responses were observed depending on the exposure to UVAR or UVBR and the dose level. No effects were observed on the biomass, ROS production or increased activity of superoxide dismutase (SOD) and catalase (CAT) compared to the control when UVR + PAR doses were lower than 9875 kJ m-2. For intermediate doses, UVR + PAR doses between 9875 and 10 275 kJ m-2, oxidative stress increased while resistance was imparted through SOD and CAT in the cells exposed to UVAR. Despite the increased antioxidant activity, biomass decrease and photosynthesis inhibition were observed, but no effects were observed with added exposure to UVBR. At the highest doses (UVR + PAR higher than 10 275 kJ m-2), the solar UVR caused decreased photosynthesis and biomass with only activation of CAT by UVBR and SOD and CAT by UVAR. In addition, for such doses, a significant decrease of microcystins (MCs, measured as MC-LR equivalents) was observed as a consequence of UVAR. This study facilitates our understanding of the SOD and CAT protection according to UVAR and UVBR doses and cellular damage and reinforces the importance of UVR as an environmental stressor. In addition, our results support the hypothesized antioxidant function of MCs.Facultad de Ciencias Exacta

The Grizzly, November 17, 1992

Ann Landers at Founder\u27s Day • Dr. Clayton Speaks on Education • An Active MSU • Elliot Speaks on Racism • Dinosaurs and Meteors • What Wismer Can Do For You • Greeks Grow With Chi Rho Psi • Top Ten Reasons Ursinus Needs a Coffeehouse • Catch of the Week • Shoulder Dancing to Depeche Mode • Voyages to Freedom Exhibit and the Jewish Experience in America • Messiah • In Their Own Words • Let\u27s See How They Like It • Concert and Jazz Bands to Perform • A Push for Physically Challenged Accessibility • Who\u27s on First? • Letters to the Editor • The Editorial Mission: Our Relationship to The Grizzly • UC Men\u27s Basketball For \u2792-\u2793 • Senior Billitto Glad He Transferred to UC • Field Hockey \u2792: A Look Back • Football Ends Tough Yearhttps://digitalcommons.ursinus.edu/grizzlynews/1305/thumbnail.jp

The Temperature Distribution of Dense Molecular Gas in the Center of NGC 253

[abridged] We present interferometric maps of ammonia (NH3) of the nearby starburst galaxy NGC 253 [star formation rate: ~2.8 Mo yr^(-1)]. The observations have been taken with the Australia Telescope Compact Array and include the para-NH3 (1,1), (2,2), and the ortho-NH3 (3,3) and (6,6) inversion lines. Six major complexes of dense ammonia are identified, three of them on either side of the starburst center, out to projected galactocentric radii of \~250 pc. [...] The application of radiative transfer large velocity gradient models reveals that the bulk of the ammonia molecules is embedded in a one-temperature gas phase. Kinetic temperatures of this gas are ~200 and 140 K toward the south-west and north-east [of the nucleus of NGC 253], respectively. The temperatures under which ammonia was formed in the past are with >~30 K also warmer toward the south-west than toward the north-east (~15-20 K). This is indicated by the ortho-to-para ammonia ratio which is ~1 and 1.5-2.5 toward the south-west and north-east, respectively. Ammonia column densities in the brightest complexes are in the range of 6-11x10^(14) cm^(-2), which adds up to a total ammonia mass of ~20 Mo, about evenly distributed toward both sides of the nucleus. [...] Toward the center of NGC 253, NH3 (1,1), (2,2), and (6,6) is detected in absorption against an unresolved continuum source. At the same location, however, ammonia (3,3) is found in emission which indicates maser activity. This would be the first detected extragalactic NH3 maser. Evidence for an expanding shell in the south-western complex is provided. [...] The shell and X-ray properties can be reproduced by the energy input of a highly obscured young stellar cluster with a mass of ~10^5 Mo which also heats the dense gas.Comment: 42 pages including 13 figures, accepted for publication in Ap