Effects of increased UV-B radiation on the lichen Cladonia arbuscula spp. mitis: UV-absorbing pigments and DNA damage

Lichens, a form of symbiosis between a fungal and a photosynthetic partner, are believed to be a group that evolved early in the history of terrestrial life. As a consequence, they probably experienced higher ultraviolet (UV) radiation fluxes than at present. However, in the last two decades, due to the depletion of the stratospheric ozone layer, increasing levels of ultraviolet-B radiation (280-315 nm) are reaching the earth€ surface. In this thesis the effects of enhanced UV-B radiation were studied on the apical (€tips€) and central (€stems€) regions of the podetial thallus of the lichen Cladonia arbuscula ssp. mitis. Effects of UV-B radiation on lichen DNA were investigated by measuring the accumulation of cyclobutane pyrimidine dimers (CPDs) by means of the enzyme-linked immunosorbant assay technique (ELISA). ELISA was also used for assessing the capacity of lichens to repair DNA damage by measuring the decrease in CPD content. UV-absorbing pigment content and changes in penetration of light within the tissue were investigated by means of spectrophotometric measurements of lichen acetone-ethanolic extracts and fibre optic measurements of internal radiation gradients, respectively. After 7 days of exposure to high light (HL; 800 _mol m-2 s-1) with or without enhanced UV-B radiation (13 kJ m-2 day-1) UV-absorbing pigments and CPDs accumulated in both tips and stems of air-dry lichens. However, stems showed a larger increase in total phenolic content and lower CPD accumulation than tips. In an outdoor experiment, after three months exposure to natural sunlight, where the UV-B component had been removed or where supplemental UV-B radiation had been added (simulating 15% ozone depletion), the highest increases in pigment content were found in stems of those lichens grown under supplemental UV-B radiation. Fibre optic measurements showed a decreased light penetration (280 nm) within the thallus of lichens grown under enhanced UV-B radiation. Short-term exposure to UV-B radiation (7.4 kJ m-2 day-1) of hydrated lichen thalli kept at either 25oC or at 2oC resulted in the accumulation of CPDs. Subsequent exposure to photosynthetically active radiation (PAR, 300 _mol m-2 s-1, 400-700 nm) decreased the CPD content only in hydrated lichen thalli kept at 25oC, whereas there was no change in thalli kept at 2oC. Exposure to UV-B radiation in combination with PAR resulted in the absence of accumulation of CPDs in hydrated lichen thalli kept at 25 oC, whereas in hydrated thalli kept at 2oC CPD levels were as high as after exposure to UV-B only. Throughout all experiments stems showed consistently lower levels of CPDs and a higher degree of repair than tips. Monitoring of photolyase repairing activity also showed that a higher percentage of pyrimidine dimers was repaired in stems than in tips. From the results it was evident that water content and temperature represent two important factors in the response of Cladonia arbuscula ssp. mitis to UV-B radiation, since air-dry thalli were more susceptible to UV-induced DNA damage and less capable of repairing CPDs than hydrated thalli. Further, hydrated thalli kept at low temperatures were not able to repair the accumulated DNA damage. An apparent protective mechanism against UV radiation in air-dry lichens was the accumulation of UV-absorbing pigments, which consequently reduced the penetration of light within the thallus. Tips have shown to be those thallus parts most susceptible to damage caused by UV-B radiation as they accumulated the highest amounts of DNA damage, exhibited the least repair capacity and the lowest relative increase in phenolic pigment content

The Interconnectivity of Trust and Appreciative Advising

Academic advisors can harness the interconnectivity of trust-building frameworks and Appreciative Advising to build relationships with students. This article proposes the integration of two trust-building frameworks within the Appreciative Advising Theory-to-Practice Framework (Bloom et al., 2008). Utilizing findings and insights from Frei and Morriss’ (2020) research on trust, the authors discuss ways that authenticity, logic, and empathy support the practice of Appreciative Advising. Exploring research from Brown (2019), the article reviews the roles of boundaries, reliability, accountability, the vault, integrity, non-judgment, and generosity in each of the six phases of Appreciative Advising. A matrix displays the intersections of trust-building actions and the Appreciative Advising phases, and the article presents examples of the impact of trust in an advising context

The effect of oxygen and carbon dioxide on the development of certain cold blooded vertebrates

Ope

Notes from “Why Not Merge the Social Sciences?” Session

The presenter discusses the similarities between natural history and anthropological studies including methods and objectives. She suggests that that the audiences are different hence questions merger

Genetic Diversity and Population Parameters of Sea Otters, \u3cem\u3eEnhydra lutris\u3c/em\u3e, before Fur Trade Extirpation from 1741–1911

All existing sea otter, Enhydra lutris, populations have suffered at least one historic population bottleneck stemming from the fur trade extirpations of the eighteenth and nineteenth centuries. We examined genetic variation, gene flow, and population structure at five microsatellite loci in samples from five pre-fur trade populations throughout the sea otter’s historical range: California, Oregon, Washington, Alaska, and Russia. We then compared those values to genetic diversity and population structure found within five modern sea otter populations throughout their current range: California, Prince William Sound, Amchitka Island, Southeast Alaska and Washington. We found twice the genetic diversity in the pre-fur trade populations when compared to modern sea otters, a level of diversity that was similar to levels that are found in other mammal populations that have not experienced population bottlenecks. Even with the significant loss in genetic diversity modern sea otters have retained historical structure. There was greater gene flow before extirpation than that found among modern sea otter populations but the difference was not statistically significant. The most dramatic effect of pre fur trade population extirpation was the loss of genetic diversity. For long term conservation of these populations increasing gene flow and the maintenance of remnant genetic diversity should be encouraged

The effect of ethylene on MAPKinase-like activity in Arabidopsis thaliana

AbstractProtein kinase activity was studied in cytosolic extracts from leaves of wild type Arabidopsis thaliana, the ethylene-insensitive mutant, etr1, and the constitutive triple-response mutant, ctr1. Treatment of wild type with ethylene resulted in increased myelin basic protein (MBP) phosphorylation. In etr1, constitutive protein kinase activity was lower than in wild type, but in ctr1, activity was enhanced. A protein of Mr∼47 kDa associated with MBP-phosphorylating activity was detected using in gel protein kinase assays and phosphorylation of this protein was promoted by ethylene treatment in wild type while activity in the mutants reflected that of MBP phosphorylation. Both MAPKinase (ERK 1) and phosphotyrosine antibodies immunoprecipitated MBP-phosphorylating activity and detected a polypeptide band at Mr∼47 kDa. Immunoprecipitated MBP-phosphorylating activity was again much lower in etr1 compared to wild type but much higher in ctr1. Antibodies to phosphorylated MAPKinase recognised proteins at ∼47 kDa and the signal was upregulated in response to ethylene. The data obtained suggest that the detected protein(s) is a MAPKinase and provide further evidence confirming that a MAPKinase cascade(s) is involved in ethylene signal transduction

Background resources and references for “The Oregon Coast before the arrival of Europeans”

Keywords: Holocene, Oregon coast, natural resources, native culture, archaeolog

Anthropological Energetics 2017: A Proposal

In the twenty-first century, energy in all its manifestations became the issue of the day. As new insights about Earth’s geo-history emerged, so did worldwide concern about human consumption of fossil energy as a force in global climate change. These insights and concerns added another dimension to anthropological examinations of how energy and energetics have affected human biological evolution and how they impact cultural developments. It is time to consider how our discipline can integrate these understandings into our anthropological worldview and practice. This paper reviews these topics and argues for an active anthropological role in shaping public perspectives on the history of Homo sapiens and the responsibilities of our species in the years ahead

Using the affective priming paradigm to explore the attitudes underlying walking behaviour

Objectives. Walking is poorly represented in memory, making it difficult to measure using self-report and even harder to predict. To circumvent this, we used the affective priming paradigm (Fazio, Sanbonmatsu, Powell, & Kardes, 1986) to assess implicit attitudes towards walking. Methods. Royal Air Force trainee aircraftsmen (N ¼ 188) wore pedometers for 1 week prior to completing the affective priming paradigm, questionnaire and interview. The affective priming paradigm involved a computer-based response latency task containing physical activity words as primes followed by adjectives as targets to be evaluated. Targets were drawn from two bipolar dichotomies, good–bad (the original Fazio et al. items) and happy–sad (mood). Results. Priming for mood items was related to levels of physical activity with high frequency participants priming for the positive (happy) pole and low frequency participants priming for the negative (sad). Both groups primed for the negative element of the Fazio (good–bad) dichotomy. Regarding walking and running, there was no differentiation on the basis of participation level. Instead, facilitated responses to happy targets contrasted with inhibited responses to sad targets for both types of locomotion. There was weak evidence that intentions to run were associated with priming of positive target items, irrespective of category. Conclusions. The relationship between implicit attitudes and behaviour is complex. Whereas implicit attitudes were related to overall exercise participation, they were not related to the specific activity of walking, despite the behaviour being mainly under automatic control.</p

Genetic Diversity and Population Parameters of Sea Otters, Enhydra lutris, before Fur Trade Extirpation from 1741–1911

All existing sea otter, Enhydra lutris, populations have suffered at least one historic population bottleneck stemming from the fur trade extirpations of the eighteenth and nineteenth centuries. We examined genetic variation, gene flow, and population structure at five microsatellite loci in samples from five pre-fur trade populations throughout the sea otter's historical range: California, Oregon, Washington, Alaska, and Russia. We then compared those values to genetic diversity and population structure found within five modern sea otter populations throughout their current range: California, Prince William Sound, Amchitka Island, Southeast Alaska and Washington. We found twice the genetic diversity in the pre-fur trade populations when compared to modern sea otters, a level of diversity that was similar to levels that are found in other mammal populations that have not experienced population bottlenecks. Even with the significant loss in genetic diversity modern sea otters have retained historical structure. There was greater gene flow before extirpation than that found among modern sea otter populations but the difference was not statistically significant. The most dramatic effect of pre fur trade population extirpation was the loss of genetic diversity. For long term conservation of these populations increasing gene flow and the maintenance of remnant genetic diversity should be encouraged