Rosmarinic Acid, as an NHE1 Activator, Decreases Skin Surface pH and Improves the Skin Barrier Function.

Stratum corneum (SC) pH regulates skin barrier functions and elevated SC pH is an important factor in various inflammatory skin diseases. Acidic topical formulas have emerged as treatments for impaired skin barriers. Sodium proton exchanger 1 (NHE1) is an important factor in SC acidification. We investigated whether topical applications containing an NHE1 activator could improve skin barrier functions. We screened plant extracts to identify NHE1 activators in vitro and found Melissa officinalis leaf extract. Rosmarinic acid, a component of Melissa officinalis leaf extract, significantly increased NHE1 mRNA expression levels and NHE1 production. Immunofluorescence staining of NHE1 in 3D-cultured skin revealed greater upregulation of NHE1 expression by NHE1 activator cream, compared to vehicle cream. Epidermal lipid analysis revealed that the ceramide level was significantly higher upon application of the NHE1 activator cream on 3D-cultured skin, compared to application of a vehicle cream. In a clinical study of 50-60-year-old adult females (n = 21), application of the NHE1 activator-containing cream significantly improved skin barrier functions by reducing skin surface pH and transepidermal water loss and increasing skin hydration, compared to patients who applied vehicle cream and those receiving no treatment. Thus, creams containing NHE1 activators, such as rosmarinic acid, could help maintain or recover skin barrier functions.

Dynamic bacterial community response to Akashiwo sanguinea (Dinophyceae) bloom in indoor marine microcosms.

We investigated the dynamics of the bacterial composition and metabolic function within Akashiwo sanguinea bloom using a 100-L indoor microcosm and metagenomic next-generation sequencing. We found that the bacterial community was classified into three groups at 54% similarity. Group I was associated with "during the A. sanguinea bloom stage" and mainly consisted of Alphaproteobacteria, Flavobacteriia and Gammaproteobacteria. Meanwhile, groups II and III were associated with the "late bloom/decline stage to post-bloom stage" with decreased Flavobacteriia and Gammaproteobacteria in these stages. Upon the termination of the A. sanguinea bloom, the concentrations of inorganic nutrients (particularly PO43-, NH4+ and dissolved organic carbon) increased rapidly and then decreased. From the network analysis, we found that the A. sanguinea node is associated with certain bacteria. After the bloom, the specific increases in NH4+ and PO43- nodes are associated with other bacterial taxa. The changes in the functional groups of the bacterial community from chemoheterotrophy to nitrogen association metabolisms were consistent with the environmental impacts during and after A. sanguinea bloom. Consequently, certain bacterial communities and the environments dynamically changed during and after harmful algal blooms and a rapid turnover within the bacterial community and their function can respond to ecological interactions.

Anti-inflammation and Anti-Cancer Activity of Ethanol Extract of Antarctic Freshwater Microalga, Micractinium sp.

Inflammation mediated by the innate immune system is an organism's protective mechanism against infectious environmental risk factors. It is also a driver of the pathogeneses of various human diseases, including cancer development and progression. Microalgae are increasingly being focused on as sources of bioactive molecules with therapeutic potential against various diseases. Furthermore, the antioxidant, anti-inflammatory, and anticancer potentials of microalgae and their secondary metabolites have been widely reported. However, the underlying mechanisms remain to be elucidated. Therefore, in this study, we investigated the molecular mechanisms underlying the anti-inflammatory and anticancer activities of the ethanol extract of the Antarctic freshwater microalga Micractinium sp. (ETMI) by several in vitro assays using RAW 264.7 macrophages and HCT116 human colon cancer cells. ETMI exerted its anti-inflammatory activity by modulating the main inflammatory indicators such as cyclooxygenase (COX)-2, interleukin (IL)-6, inducible nitric oxide synthase (iNOS), tumor necrosis factor (TNF)-α, and nitric oxide (NO) in a dose-dependent manner. In addition, ETMI exerted cytotoxic activity against HCT116 cells in a dose-dependent manner, leading to significantly reduced cancer cell proliferation. Further, it induced cell cycle arrest in the G1 phase through the regulation of hallmark genes of the G1/S phase transition, including CDKN1A, and cyclin-dependent kinase 4 and 6 (CDK4 and CDK6, respectively). At the transcriptional level, the expression of CDKN1A gradually increased in response to ETMI treatment while that of CDK4 and CDK6 decreased. Taken together, our findings suggest that the anti-inflammatory and anticancer activities of the Antarctic freshwater microalga, Micractinium sp., and ETMI may provide a new clue for understanding the molecular link between inflammation and cancer and that ETMI may be a potential anticancer agent for targeted therapy of colorectal cancer.

Effects of temperature and nutrients on changes in genetic diversity of bacterioplankton communities in a semi-closed bay, South Korea.

Bacterioplankton communities in a semi-closed bay (Jangmok Bay, South Korea) were analysed using a 16S rDNA multiplex 454 pyrosequencing approach. Diversity and operational taxonomic units of bacterioplankton communities in the Jangmok Bay are highest in cold water seasons and lowest in warm water ones. During cold seasons, α-proteobacteria respond rapidly to pulses of the concentration of inorganic nutrients, while γ-proteobacteria during warm water seasons are the most active type of bacterioplankton resent in the prevailing conditions, which include high dissolved organic carbon, chemical oxygen demand and primary production. Cyanobacteria, a minor group constituting 4.58% of the total bacterioplankton, are more abundant at low temperature. Flavobacteria are more abundant in nutrient-rich conditions and the abundance of this group also demonstrated a delayed decline following summer phytoplankton blooms. The pronounced seasonal oscillations in phosphorus concentration and temperature exert strong selection pressure on bacterioplankton communities.

Utilizing the algicidal activity of aminoclay as a practical treatment for toxic red tides.

In recent decades, harmful algal blooms (HABs) - commonly known as red tides - have increasingly impacted human health, caused significant economic losses to fisheries and damaged coastal environments and ecosystems. Here, we demonstrate a method to control and suppress HABs through selective algal lysis. The approach harnesses the algicidal effects of aminoclays, which are comprised of a high density of primary amine groups covalently bonded by metal cation backbones. Positively charged colloidals of aminoclays induce cell lysis in HABs within several minutes exposure but have negligible impact on non-harmful phytoplankton, zooplankton and farmed fish. This selective lysis is due to the ammonium characteristics of the aminoclay and the electrostatic attraction between the clay nanoparticles and the algal cells. In contrast, yellow loess clay, a recognized treatment for HABs, causes algal flocs with little cell lysis. Thus, the aminoclay loading can be effective for the mitigation of HABs.

Mesocosm study on weathering characteristics of Iranian Heavy crude oil with and without dispersants.

The environmental fate of Iranian Heavy crude oil (IHC) with and without an added oil spill dispersant (OSD) has been studied using a 1000 kL capacity in situ mesocosm. Physical weathering and chemical composition changes of the oil were monitored for 77 days. Compound-specific effects of the OSD could be observed as changes over time in the content of the total petroleum hydrocarbon (TPH), unresolved complex mixture (UCM), alkanes, polycyclic aromatic hydrocarbons (PAHs), hopanes and steranes in the oil. As oil weathers, most hydrocarbons showed a rapid decreasing phase followed by a slowdown and stabilization. Recalcitrant biomarkers, however, showed a different trend. An increase in hydrocarbon contents in the form of UCM occurred after OSD treatment. The enhanced solubility of the low molecular weight PAHs by the OSD decreased the half-life of the alkylated PAHs in the OD. After 77 days of exposure at the sea surface, both the oils with and without the OSD exhibited moderate weathering. Most of the source diagnostic indices maintained their source information, and the weathering indices indicated that evaporation, dissolution, and dispersion were the major weathering processes. The mass balance of the weathered oil was calculated using laboratory and mesocosm data and the results demonstrate the importance of using a mesocosm for the production of environmentally realistic data.

Stronger impact of dispersant plus crude oil on natural plankton assemblages in short-term marine mesocosms.

To assess the effects of crude oil and dispersant on marine planktonic ecosystems, analyses were performed in 1000-L mesocosm over a period of nine days. Triplicate experiments were conducted for two different treatments, namely, addition of crude oil alone and oil plus dispersant. In the mesocosm with oil plus dispersant, high concentrations of total petroleum hydrocarbon (TPH) were soon found in the bottom layer. In addition, most planktonic communities responded drastically to the presence of dispersant acting to disperse TPH: total bacterial abundances increased for the first two days and then decreased rapidly for the remainder of the experiment. The abundance of heterotrophic flagellates increased rapidly in association with the increase in bacterial cells. The abundance of phytoplankton and zooplankton communities decreased clearly within two days. Time-delayed relationship also revealed that the TPH concentration had a significant negative relationship with phyto- and zooplankton communities within two days. However, most planktonic communities were affected less adversely in the mesocosms treated with crude oil alone than in those treated with both crude oil and dispersant. The present results demonstrate that the planktonic ecosystem was damaged more severely by the introduction of dispersant than by the harmful effects of crude oil itself. Therefore, caution should be taken when considering the direct application of dispersant in natural environments, even though it has the advantage of rapidly removing crude oil.

Effects of crude oil on marine microbial communities in short term outdoor microcosms.

To assess the effects of crude oil spills on marine microbial communities, 10 L outdoor microcosms were manipulated over an exposure period of 8 days. The responses of microbial organisms exposed to five crude oil concentrations in 10 to 10,000 ppm (v/v) were monitored in the microcosms. The abundance of microalgae and copepods decreased rapidly upon the addition of crude oil at concentrations over 1,000 ppm, whereas the total density of heterotrophic bacteria increased dramatically at the higher concentrations. Bacterial diversity, determined by denaturing gradient gel electrophoresis, was increased at higher concentrations. In particular, the intensity of the bands representing Jannaschia sp. and Sulfitobacter brevis increased with the addition of oil. These results indicate that crude oil spills with concentrations over 1,000 ppm seriously affected the structure of the microbial communities.