scholarly journals Role of environmental factors on phytoplankton bloom initiation under landfast sea ice in Resolute Passage, Canada

2014 ◽  
Vol 497 ◽  
pp. 39-49 ◽  
Author(s):  
CJ Mundy ◽  
M Gosselin ◽  
Y Gratton ◽  
K Brown ◽  
V Galindo ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Sea Ice ◽  
Phytoplankton Bloom ◽  
Landfast Sea Ice

scholarly journals The biogeochemical role of a microbial biofilm in sea ice

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Arnout Roukaerts ◽  
Florian Deman ◽  
Fanny Van der Linden ◽  
Gauthier Carnat ◽  
Arne Bratkic ◽  
...  
Keyword(s):  
Sea Ice ◽  
Algal Blooms ◽  
Nutrient Concentrations ◽  
Community Attachment ◽  
Microbial Biofilm ◽  
Autotrophic Biomass ◽  
High Concentrations ◽  
Landfast Sea Ice ◽  
Carbon Concentrations

A paradox is commonly observed in productive sea ice in which an accumulation in the macro-nutrients nitrate and phosphate coincides with an accumulation of autotrophic biomass. This paradox requires a new conceptual understanding of the biogeochemical processes operating in sea ice. In this study, we investigate this paradox using three time series in Antarctic landfast sea ice, in which massive algal blooms are reported (with particulate organic carbon concentrations up to 2,600 µmol L–1) and bulk nutrient concentrations exceed seawater values up to 3 times for nitrate and up to 19 times for phosphate. High-resolution sampling of the bottom 10 cm of the cores shows that high biomass concentrations coexist with high concentrations of nutrients at the subcentimeter scale. Applying a nutrient-phytoplankton-zooplankton-detritus model approach to this sea-ice system, we propose the presence of a microbial biofilm as a working hypothesis to resolve this paradox. By creating microenvironments with distinct biogeochemical dynamics, as well as favoring nutrient adsorption onto embedded decaying organic matter, a biofilm allows the accumulation of remineralization products (nutrients) in proximity to the sympagic (ice-associated) community. In addition to modifying the intrinsic physicochemical properties of the sea ice and providing a substrate for sympagic community attachment, the biofilm is suggested to play a key role in the flux of matter and energy in this environment.

Questions on the role of biofilms for the adaptation of microorganisms to unfavorable environmental factors by the example of P. aeruginosa

2020 ◽  
Vol 99 (4) ◽  
pp. 379-383
Author(s):  
Vasily N. Afonyushkin ◽  
N. A. Donchenko ◽  
Ju. N. Kozlova ◽  
N. A. Davidova ◽  
V. Yu. Koptev ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Environmental Factors ◽  
Barrier Function ◽  
Infectious Agent ◽  
Antagonistic Activity ◽  
The Body ◽  
Main Function ◽  
Pathogenic Potential ◽  
The Face

Pseudomonas aeruginosa is a widely represented species of bacteria possessing of a pathogenic potential. This infectious agent is causing wound infections, fibrotic cystitis, fibrosing pneumonia, bacterial sepsis, etc. The microorganism is highly resistant to antiseptics, disinfectants, immune system responses of the body. The responses of a quorum sense of this kind of bacteria ensure the inclusion of many pathogenicity factors. The analysis of the scientific literature made it possible to formulate four questions concerning the role of biofilms for the adaptation of P. aeruginosa to adverse environmental factors: Is another person appears to be predominantly of a source an etiological agent or the source of P. aeruginosa infection in the environment? Does the formation of biofilms influence on the antibiotic resistance? How the antagonistic activity of microorganisms is realized in biofilm form? What is the main function of biofilms in the functioning of bacteria? A hypothesis has been put forward the effect of biofilms on the increase of antibiotic resistance of bacteria and, in particular, P. aeruginosa to be secondary in charcter. It is more likely a biofilmboth to fulfill the function of storing nutrients and provide topical competition in the face of food scarcity. In connection with the incompatibility of the molecular radii of most antibiotics and pores in biofilm, biofilm is doubtful to be capable of performing a barrier function for protecting against antibiotics. However, with respect to antibodies and immunocompetent cells, the barrier function is beyond doubt. The biofilm is more likely to fulfill the function of storing nutrients and providing topical competition in conditions of scarcity of food resources.

Role of environmental factors in the etiology of hepatocellular carcinoma

2010 ◽  
Vol 151 (28) ◽  
pp. 1132-1136 ◽  
Author(s):  
István Tornai
Keyword(s):  
Hepatocellular Carcinoma ◽  
Hepatitis B Virus ◽  
Environmental Factors ◽  
Hepatitis B ◽  
Hepatitis A ◽  
Virus Hepatitis ◽  
B Virus

A krónikus vírushepatitisek jelentik ma a legismertebb okokat a hepatocellularis carcinoma (HCC) kialakulásában. A krónikus B- és C-vírus-hepatitis a májrákok körülbelül 40-50%-át okozza. A nyugati típusú társadalmakban a HCC előfordulása folyamatosan növekvő tendenciát mutat. Az alkohol számít a környezeti tényezők közül a legfontosabbnak, bár az alkoholfogyasztás a legtöbb országban csökken. Ez aláhúzza az egyéb környezeti tényezők fontosságát is. Az elfogyasztott alkoholmennyiséggel egyenes arányban növekszik a cirrhosis és a következményes HCC gyakorisága nőkben és férfiakban egyaránt. A kémiai anyagok közül a legismertebb a Kínában és Afrikában elterjedt aflatoxin, amely a gabonaféléket szennyező mycotoxin. Hasonló területeken endémiás, mint a hepatitis B-vírus, együtt szinergista hatást fejtenek ki. A dohányzás is egyértelműen bizonyított hepatocarcinogen hatással rendelkezik. Ez is jelentősen fokozódik, ha alkoholfogyasztással vagy vírushepatitisszel társul. Társadalmilag talán a legfontosabb az elhízás, a következményes nem alkoholos zsírmáj, illetve steatohepatitis és a 2-es típusú cukorbetegség, amelyek prevalenciája egyre fokozódik. Feltehetően ezek állnak a növekvő HCC-gyakoriság hátterében. Az inzulinrezisztencia és az oxidatív stressz képezik a legfontosabb patogenetikai lépéseket a májsejtkárosodásban. További fontos rizikótényező az orális fogamzásgátlók elterjedt használata. Egyes foglalkozások esetén a tartós szervesoldószer-expozíció is növeli a HCC rizikóját. Védelmet jelenthetnek az antioxidánsok, a szelén, a gyógyszerek közül a statinok és a feketekávé-fogyasztás.

Trends in Arctic sea ice and the role of atmospheric circulation

2013 ◽  
Vol 14 (2) ◽  
pp. 97-101 ◽  
Author(s):  
Masayo Ogi ◽  
Ignatius G. Rigor
Keyword(s):  
Sea Ice ◽  
Atmospheric Circulation ◽  
Arctic Sea Ice ◽  
Arctic Sea

scholarly journals Impact of Environmental Factors on Stilbene Biosynthesis

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 90
Author(s):  
Alessio Valletta ◽  
Lorenzo Maria Iozia ◽  
Francesca Leonelli
Keyword(s):  
Environmental Factors ◽  
Biosynthetic Pathway ◽  
In Planta ◽  
Organ Cultures ◽  
Related Plant ◽  
Valuable Compounds ◽  
Stilbene Compounds ◽  
Stilbene Biosynthesis ◽  
Abiotic Environmental Factors

Stilbenes are a small family of polyphenolic secondary metabolites that can be found in several distantly related plant species. These compounds act as phytoalexins, playing a crucial role in plant defense against phytopathogens, as well as being involved in the adaptation of plants to abiotic environmental factors. Among stilbenes, trans-resveratrol is certainly the most popular and extensively studied for its health properties. In recent years, an increasing number of stilbene compounds were subjected to investigations concerning their bioactivity. This review presents the most updated knowledge of the stilbene biosynthetic pathway, also focusing on the role of several environmental factors in eliciting stilbenes biosynthesis. The effects of ultraviolet radiation, visible light, ultrasonication, mechanical stress, salt stress, drought, temperature, ozone, and biotic stress are reviewed in the context of enhancing stilbene biosynthesis, both in planta and in plant cell and organ cultures. This knowledge may shed some light on stilbene biological roles and represents a useful tool to increase the accumulation of these valuable compounds.

scholarly journals Spectral albedo of coastal landfast sea ice in Prydz Bay, Antarctica

2020 ◽  
pp. 1-11
Author(s):  
Guanghua Hao ◽  
Roberta Pirazzini ◽  
Qinghua Yang ◽  
Zhongxiang Tian ◽  
Changwei Liu
Keyword(s):  
Sea Ice ◽  
Near Infrared ◽  
Elevation Angle ◽  
Early Summer ◽  
Prydz Bay ◽  
Katabatic Wind ◽  
Surface Conditions ◽  
Zhongshan Station ◽  
Landfast Sea Ice ◽  
Two Phases

Abstract The surface spectral albedo was measured over coastal landfast sea ice in Prydz Bay (off Zhongshan Station), East Antarctica from 5 October to 26 November of 2016. The mean albedo decreased from late-spring to early-summer, mainly responding to the change in surface conditions from dry (phase I) to wet (phase II). The evolution of the albedo was strongly influenced by the surface conditions, with alternation of frequent snowfall events and katabatic wind that induce snow blowing at the surface. The two phases and day-to-day albedo variability were more pronounced in the near-infrared albedo wavelengths than in the visible ones, as the near-infrared photons are more sensitive to snow metamorphism, and to changes in the uppermost millimeters and water content of the surface. The albedo diurnal cycle during clear sky conditions was asymmetric with respect to noon, decreasing from morning to evening over full and patchy snow cover, and decreasing more rapidly in the morning over bare ice. We conclude that snow and ice metamorphism and surface melting dominated over the solar elevation angle dependency in shaping the albedo evolution. However, we realize that more detailed surface observations are needed to clarify and quantify the role of the various surface processes.

scholarly journals The Implications of Pruritogens in the Pathogenesis of Atopic Dermatitis

2021 ◽  
Vol 22 (13) ◽  
pp. 7227
Author(s):  
Lai-San Wong ◽  
Yu-Ta Yen ◽  
Chih-Hung Lee
Keyword(s):  
Atopic Dermatitis ◽  
Environmental Factors ◽  
Immune Responses ◽  
Immune Cells ◽  
Inflammatory Disease ◽  
Targeted Therapies ◽  
Skin Barrier ◽  
Skin Barrier Function ◽  
Inflammatory Molecules

Atopic dermatitis (AD) is a prototypic inflammatory disease that presents with intense itching. The pathophysiology of AD is multifactorial, involving environmental factors, genetic susceptibility, skin barrier function, and immune responses. A recent understanding of pruritus transmission provides more information about the role of pruritogens in the pathogenesis of AD. There is evidence that pruritogens are not only responsible for eliciting pruritus, but also interact with immune cells and act as inflammatory mediators, which exacerbate the severity of AD. In this review, we discuss the interaction between pruritogens and inflammatory molecules and summarize the targeted therapies for AD.

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