scholarly journals The presence of usnic acid does not protect the lichen Cladina arbuscula subsp. mitis against the long-term copper excess

2015 ◽  
Vol 100 ◽  
pp. 94-100 ◽  
Author(s):  
M. Bačkorová ◽  
I. Biľová ◽  
T. Kimáková ◽  
M. Bačkor
Keyword(s):  
Usnic Acid ◽  
Copper Excess

scholarly journals A clonal fresh water plants acquires transgenerational stress resistance under recurring copper excess

2021 ◽  
Author(s):  
Meret Huber ◽  
Saskia Gablenz ◽  
Martin Höfer
Keyword(s):  
Stress Responses ◽  
Plant Ecology ◽  
Copper Accumulation ◽  
Plant Fitness ◽  
Genetic Inheritance ◽  
Spirodela Polyrhiza ◽  
Transgenerational Plasticity ◽  
Copper Excess ◽  
Water Plants

ABSTRACTAlthough non-genetic inheritance is thought to play an important role in plant ecology and evolution, evidence for adaptive transgenerational plasticity is scarce. Here, we investigated the consequences of copper excess on offspring defences and fitness in the giant duckweed (Spirodela polyrhiza) across multiple asexual generations. We found that exposing large monoclonal populations (>10,000 individuals) for 30 generations to copper excess decreased plant fitness during the first few generations but increased their fitness in consecutive generations under recurring stress when plants were grown for 5 generations under control conditions prior recurring conditions. Similarly, propagating individual plants as single descendants for 5 or 10 generations under copper excess decreased plant fitness when 5 generations and improved plant fitness when 10 generations passed between initial and recurring stress; thus, transgenerational stress responses likely contributed to the observed variations in offspring fitness of long-term copper exposed populations. Fitness benefits under recurring stress were partially associated with avoidance of excessive copper accumulation, which in turn correlated with transgenerationally modified flavonoid concentrations. Taken together, these data demonstrate time-dependent adaptive transgenerational responses under recurring stress, which highlights the importance of non-genetic inheritance for plant ecology and evolution.

Photosynthesis and Water Relations in Tomato Plants Cultivated Long-Term in Media Containing (+)-Usnic Acid

2006 ◽  
Vol 32 (9) ◽  
pp. 2053-2066 ◽  
Author(s):  
E. Latkowska ◽  
Z. Lechowski ◽  
J. Bialczyk ◽  
J. Pilarski
Keyword(s):  
Water Relations ◽  
Usnic Acid ◽  
Tomato Plants

scholarly journals Simulated global warming increases usnic acid but reduces perlatolic acid in the mat-forming terricolous lichen Cladonia stellaris

2017 ◽  
Vol 49 (3) ◽  
pp. 269-274 ◽  
Author(s):  
Johan ASPLUND ◽  
Andy SIEGENTHALER ◽  
Yngvar GAUSLAA
Keyword(s):  
Global Warming ◽  
Extreme Environments ◽  
Usnic Acid ◽  
Secondary Compounds ◽  
Growing Season ◽  
Ambient Conditions ◽  
Symbiotic Associations ◽  
Slow Growing ◽  
Terricolous Lichen

AbstractLichens as sessile and slow-growing symbiotic associations have evolved various carbon-based secondary compounds (CBSCs) to mitigate the effects of some stressors in the extreme environments in which they often grow. The mat-forming lichen Cladonia stellaris, an important fodder for reindeer, produces usnic acid in the outermost layer and perlatolic acid in the medulla. Here, we studied effects of simulated global warming on these CBSCs in C. stellaris cultivated in climate chambers with: 1) ambient conditions as control or 2) ambient conditions +4°C. The chambers simulated, at an hourly resolution, an averaged 10-year growing season dynamic from a long-term monitored boreal mire in northern Sweden. After two months of acclimation, +4°C warming in one simulated growing season increased the concentration of usnic acid by 31% compared with ambient conditions, whereas the warming decreased the concentration of perlatolic acid by 14%. Since lichen CBSCs play important roles in ecosystem processes such as lichenivory and decomposition, these changes may profoundly affect lichen-dominated ecosystems.

scholarly journals Sustained release of usnic acid from graphene coatings ensures long term antibiofilm protection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Santosh Pandit ◽  
Shadi Rahimi ◽  
Abderahmane Derouiche ◽  
Athmane Boulaoued ◽  
Ivan Mijakovic
Keyword(s):  
Sustained Release ◽  
Bacterial Colonization ◽  
Usnic Acid ◽  
Bacterial Biofilm ◽  
Second Phase ◽  
Burst Release ◽  
Medical Sector ◽  
Important Challenge ◽  
Biofilm Development

AbstractProtecting surfaces from bacterial colonization and biofilm development is an important challenge for the medical sector, particularly when it comes to biomedical devices and implants that spend longer periods in contact with the human body. A particularly difficult challenge is ensuring long-term protection, which is usually attempted by ensuring sustained release of antibacterial compounds loaded onto various coatings. Graphene have a considerable potential to reversibly interact water insoluble molecules, which makes them promising cargo systems for sustained release of such compounds. In this study, we developed graphene coatings that act as carriers capable of sustained release of usnic acid (UA), and hence enable long-term protection of surfaces against colonization by bacterial pathogens Staphylococcus aureus and Staphylococcus epidermidis. Our coatings exhibited several features that made them particularly effective for antibiofilm protection: (i) UA was successfully integrated with the graphene material, (ii) a steady release of UA was documented, (iii) steady UA release ensured strong inhibition of bacterial biofilm formation. Interestingly, even after the initial burst release of UA, the second phase of steady release was sufficient to block bacterial colonization. Based on these results, we propose that graphene coatings loaded with UA can serve as effective antibiofilm protection of biomedical surfaces.

scholarly journals Physiological responses of Xanthoria parietina to longterm copper excess: Role of the extracellular secondary metabolite parietin

2019 ◽  
Vol 43 (2) ◽  
pp. 133-142
Author(s):  
Ivana Biľová ◽  
Michal Goga ◽  
Martin Backor
Keyword(s):  
Secondary Metabolite ◽  
Chlorophyll A ◽  
De Novo ◽  
Physiological Parameters ◽  
Term Experiment ◽  
Xanthoria Parietina ◽  
Long Term Experiment ◽  
Lichen Thallus ◽  
Copper Excess

Xanthoria parietina is a common lichen that is widespread around the world. Tolerance of heavy metal pollution in this lichen is well known. Xanthoria parietina contains the secondary metabolite parietin, which protects the photobiont from high UV- radiation. Secondary metabolites of lichens have been found to form complexes with metal cations. In a long-term experiment (lasting 8 weeks), we tested the resistance of X. parietina with and without the secondary metabolite parietin against two concentrations of Cu (50 ?M and 500 ?M). Removal of parietin did not affect the measured physiological parameters. However, it caused higher accumulation of intracellular Cu. De novo synthesis of parietin in the lichen thallus after removal of the metabolite was not observed. Physiological parameters (chlorophyll a fluorescence, chlorophyll a integrity, content of soluble proteins, ergosterol levels, TBARS production) were affected by the higher dose of Cu during the long-term experiment. It seems that the secondary metabolite parietin does not protect the lichen against Cu excess.

scholarly journals Insecticidal and Antiprotozoal Properties of Lichen Secondary Metabolites on Insect Vectors and Their Transmitted Protozoal Diseases to Humans

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 342
Author(s):  
Arthur M. Muhoro ◽  
Edit É. Farkas
Keyword(s):  
Secondary Metabolites ◽  
Morphological Changes ◽  
Usnic Acid ◽  
Bibliographic Databases ◽  
Insect Vectors ◽  
Negative Effects ◽  
Parasitic Protozoa ◽  
Larval Stages ◽  
Synthetic Chemicals

Since the long-term application of synthetic chemicals as insecticides and the chemotherapy of protozoal diseases have had various negative effects (non-target effects, resistance), research on less harmful biological products is underway. This review is focused on lichens with potential insecticidal and antiprotozoal activity. Literature sources (27) were surveyed from five bibliographic databases and analyzed according to the taxonomic group of the insect, the protozoal disease and the lichen, the type of bioactive compounds (including method of application and mount applied), and the potential bioactivity based on mortalities caused after 24 h of exposure on insects and on parasitic protozoa. Six species of protozoa and five species of mosquitoes, three kinds of larval stages of insects and three protozoa stages were tested. Insecticidal and antiprotozoal effects of crude extracts and seven lichen secondary metabolites (mostly usnic acid) of 32 lichen species were determined. Physiological and morphological changes on parasitic protozoa were observed. Mortality rates caused by LSMs on insect vectors closer to (or somewhat above) the WHO threshold were considered to be insecticides. The results are based on laboratory experiments; however, the efficacy of metabolites should be confirmed in the field and on non-human primates to control the insect vectors and human protozoal diseases transmitted by insects.

Therapy and prevention for mental health: What if mental diseases are mostly not brain disorders?

2019 ◽  
Vol 42 ◽  
Author(s):  
John P. A. Ioannidis
Keyword(s):  
Mental Health ◽  
Mental Disease ◽  
Brain Disorders ◽  
Social Stressors ◽  
Labor Education ◽  
Mental Diseases ◽  
Long Term Follow Up ◽  
Political Decisions

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

Brief summary of Kleť photographic search programme for minor planets

1999 ◽  
Vol 173 ◽  
pp. 189-192
Author(s):  
J. Tichá ◽  
M. Tichý ◽  
Z. Moravec
Keyword(s):  
Ccd Camera ◽  
Minor Planet ◽  
Minor Planets ◽  
Main Belt

AbstractA long-term photographic search programme for minor planets was begun at the Kleť Observatory at the end of seventies using a 0.63-m Maksutov telescope, but with insufficient respect for long-arc follow-up astrometry. More than two thousand provisional designations were given to new Kleť discoveries. Since 1993 targeted follow-up astrometry of Kleť candidates has been performed with a 0.57-m reflector equipped with a CCD camera, and reliable orbits for many previous Kleť discoveries have been determined. The photographic programme results in more than 350 numbered minor planets credited to Kleť, one of the world's most prolific discovery sites. Nearly 50 per cent of them were numbered as a consequence of CCD follow-up observations since 1994.This brief summary describes the results of this Kleť photographic minor planet survey between 1977 and 1996. The majority of the Kleť photographic discoveries are main belt asteroids, but two Amor type asteroids and one Trojan have been found.

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