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"Acidification"
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Publisher Correction: Farming with crops and rocks to address global climate, food and soil security
In the version of this Perspective originally published, 'acidification' was incorrectly spelt as 'adification' in Fig. 4. This has now been corrected.
Journal Article
Two sets of amino acids of the domain I of Cav2.3 Ca super(2+) channels contribute to their high sensitivity to extracellular protons
Extracellular acidification decreases Ca super(2+) current amplitude and produces a depolarizing shift in the activation potential (Va) of voltage-gated Ca super(2+) channels (VGCC). These effects are common to all VGCC, but differences exist between Ca super(2+) channel types and the underlying molecular mechanisms remain largely unknown. We report here that the changes in current amplitude induced by extracellular acidification or alkalinisation are more important for Cav2.3 R type than for Cav2.1 P/Q-type Ca super(2+) channels. This difference results from a higher shift of Va combined with a modification of channel conductance. Although involved in the sensitivity of channel conductance to extracellular protons, neither the EEEE locus nor the divalent cation selectivity locus could explain the specificity of the pH effects. We show that this specificity involves two separate sets of amino acids within domain I of the Cav alpha subunit. Residues of the voltage sensor domain and residues in the pore domain mediate the effects of extracellular protons on Va and on channel conductance, respectively. These new insights are important for elucidating the molecular mechanisms that control VGCC gating and conductance and for understanding the role of extracellular protons in other channels or membrane-tethered enzymes with similar pore and/or voltage sensor domains.
Journal Article
Individual Pattern Response to COsub.2-Induced Acidification Stress in IHaliotis rufescens/I Suggests Stage-Specific Acclimatization during Its Early Life History
The red abalone Haliotis rufescens is a pivotal marine resource in the context of worldwide abalone aquaculture. However, the species has been listed as critically endangered partly because of the life-history massive mortalities associated with habitat climate changes, including short- and long-term ocean acidification. Because abalone survival depends on its early life history success, figuring out its vulnerability to acidification is the first step to establishing culture management strategies. In the present study, red abalone embryos were reared under long-term CO[sub.2]-induced acidification (pH 7.8 and 7.6) and evaluated. The impairment prevalence was assessed during their larval stages, considering the developmental success, growth and calcification. The result in the stage-specific disturbance suggests that the body abilities evaluated are at the expense of their development stages, of which the critical threshold is found under −0.4 pH units. Finally, the settlement was short-term stressed, displaying the opposite to that observed in the long-term acidification. Thus, the early life history interacts through multiple pathways that may also depend on the acidification challenge (i.e., short or long term). Understanding the tolerance limits and pathways of the stress response provides valuable insights for exploring the vulnerability of H. rufescens to ocean acidification.
Journal Article
Ocean Acidification
The ocean has absorbed a significant portion of all human-made carbon dioxide emissions. This benefits human society by moderating the rate of climate change, but also causes unprecedented changes to ocean chemistry. Carbon dioxide taken up by the ocean decreases the pH of the water and leads to a suite of chemical changes collectively known as ocean acidification. The long term consequences of ocean acidification are not known, but are expected to result in changes to many ecosystems and the services they provide to society. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean reviews the current state of knowledge, explores gaps in understanding, and identifies several key findings.
Like climate change, ocean acidification is a growing global problem that will intensify with continued CO2 emissions and has the potential to change marine ecosystems and affect benefits to society. The federal government has taken positive initial steps by developing a national ocean acidification program, but more information is needed to fully understand and address the threat that ocean acidification may pose to marine ecosystems and the services they provide. In addition, a global observation network of chemical and biological sensors is needed to monitor changes in ocean conditions attributable to acidification.
eBook
Correction to: Impacts of ocean acidification on hermit crab communities through contrasting responses of Pagurus filholi
Figure 2 has been published incorrectly in the original publication of the article.
Journal Article
Assembly of Bio-Nanoparticles for Double Controlled Drug Release: e74679
A critical limiting factor of chemotherapy is the unacceptably high toxicity. The use of nanoparticle based drug carriers has significantly reduced the side effects and facilitated the delivery of drugs. Source of the remaining side effect includes (1) the broad final in vivo distribution of the administrated nanoparticles, and (2) strong basal drug release from nanoparticles before they could reach the tumor. Despite the advances in pH-triggered release, undesirable basal drug release has been a constant challenge under in vivo conditions. In this study, functionalized single walled carbon nanohorn supported immunoliposomes were assembled for paclitaxel delivery. The immunoliposomes were formulated with polyethylene glycol, thermal stable and pH sensitive phospholipids. Each nanohorn was found to be encapsulated within one immunoliposome. Results showed a highly pH dependent release of paclitaxel in the presence of serum at body temperature with minimal basal release under physiological conditions. Upon acidification, paclitaxel was released at a steady rate over 30 days with a cumulative release of 90% of the loaded drug. The drug release results proved our hypothesized double controlled release mechanism from the nanoparticles. Other results showed the nanoparticles have doubled loading capacity compared to that of traditional liposomes and higher affinity to breast cancer cells overexpressing Her2 receptors. Internalized nanoparticles were found in lysosomes.
Journal Article
And on Top of All That
Oceanic and coastal waters are acidifying due to processes dominated in the open ocean by increasing atmospheric CO₂ and dominated in estuaries and some coastal waters by nutrient-fueled respiration. The patterns and severity of acidification, as well as its effects, are modified by the host of stressors related to human activities that also influence these habitats. Temperature, deoxygenation, and changes in food webs are particularly important co-stressors because they are pervasive, and both their causes and effects are often mechanistically linked to acidification. Development of a theoretical underpinning to multiple stressor research that considers physiological, ecological, and evolutionary perspectives is needed because testing all combinations of stressors and stressor intensities experimentally is impossible. Nevertheless, use of a wide variety of research approaches is a logical and promising strategy for improving understanding of acidification and its effects. Future research that focuses on spatial and temporal patterns of stressor interactions and on identifying mechanisms by which multiple stressors affect individuals, populations, and ecosystems is critical. It is also necessary to incorporate consideration of multiple stressors into management, mitigation, and adaptation to acidification and to increase public and policy recognition of the importance of addressing acidification in the context of the suite of other stressors with which it potentially interacts.
Journal Article