The distribution of submerged macrophytes in response to intense solar radiation and salinity reveals hydrogen peroxide as an abiotic stress indicator.

The feasible condition for submerged macrophyte growth is hard to understand as many environmental factors contribute to establishing macrophyte distribution with different intensities generating excess reactive oxygen species (ROS). Among various kinds of ROS, hydrogen peroxide (H2O2) is relatively stable and can be measured accurately. Thus, for the quantification of submerged macrophyte species, H2O2 can be used to evaluate their distribution in a lake. Submerged macrophytes, such as Potamogeton anguillanus, were abundant in Lake Shinji. The largest biomass distribution was around 1.35 m deep, under low solar radiation intensity, and nearly no biomass was found less than 0.3 m deep, where solar radiation was high. Tissue H2O2 concentrations varied in response to the diurnal photosynthetically active radiation (PAR) intensity, which was followed by antioxidant activities, though slightly delayed. Laboratory experiments were conducted with different PAR intensities or salinity concentrations. A stable level of H2O2 was maintained up to about 200 µmol m-2 s-1 of PAR for 30 days, followed by a gradual increase as PAR increased. The H2O2 concentration increased with higher salinity. A change in Chlorophyll a (Chl-a) concentration is associated with an altering H2O2 concentration, following a unique negative relationship with H2O2 concentration. If H2O2 exceeded 45 µmol/gFW, the homeostasis collapsed, and H2O2 and Chl-a significantly declined afterward. The above findings indicate that H2O2 has a negative effect on the physiological condition of the plant. The increase in H2O2 concentration was prevented by antioxidant activities, which elevated with increasing H2O2 concentration.

Increased levels of interleukin-33 associated with bone erosion and interstitial lung diseases in patients with rheumatoid arthritis.

OBJECTIVE: To analyze the levels of interleukin-33 (IL-33) in the serum of patients with rheumatoid arthritis (RA) and investigated its possible pathophysiological importance. METHODS: The concentrations of IL-33 and matrix metalloproteinase (MMP)-3 were measured by enzyme-linked immunosorbent assay (ELISA) in the serum of 121 patients with RA and 47 controls. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), and anticyclic citrullinated peptide (anti-CCP) were measured by standard laboratory techniques. Interstitial lung disease (ILD) was identified on high-resolution computed tomography. Disease activity in RA was scored with the Disease Activity Score 28 based on C-reactive protein levels (DAS28-CRP). The bone erosion of RA patients was evaluated by modified Sharp Score (MSS). RESULTS: Serum levels of IL-33 and MMP-3 were significantly higher in RA patients than in healthy controls. Significant higher levels of IL-33 were found in CCP-positive group and in patients with ILD. There was positive correlation between the levels of IL-33 and RF. Moreover, there was also positive correlation between IL-33 and MMP-3, MSS. CONCLUSION: These data support the hypothesis that IL-33 may be involved in RA pathogenesis and it may partly contribute to the bone erosion in RA patients.

Hydrogen Peroxide Variation Patterns as Abiotic Stress Responses of Egeria densa.

In vegetation management, understanding the condition of submerged plants is usually based on long-term growth monitoring. Reactive oxygen species (ROS) accumulate in organelles under environmental stress and are highly likely to be indicators of a plant's condition. However, this depends on the period of exposure to environmental stress, as environmental conditions are always changing in nature. Hydrogen peroxide (H2O2) is the most common ROS in organelles. The responses of submerged macrophytes, Egeria densa, to high light and iron (Fe) stressors were investigated by both laboratory experiments and natural river observation. Plants were incubated with combinations of 30-200 µmol m-2 s-1 of photosynthetically active radiation (PAR) intensity and 0-10 mg L-1 Fe concentration in the media. We have measured H2O2, photosynthetic pigment concentrations, chlorophyll a (Chl-a), chlorophyll b (Chl-b), carotenoid (CAR), Indole-3-acetic acid (IAA) concentrations of leaf tissues, the antioxidant activity of catalase (CAT), ascorbic peroxidase (APX), peroxidase (POD), the maximal quantum yield of PSII (Fv Fm -1), and the shoot growth rate (SGR). The H2O2 concentration gradually increased with Fe concentration in the media, except at very low concentrations and at an increased PAR intensity. However, with extremely high PAR or Fe concentrations, first the chlorophyll contents and then the H2O2 concentration prominently declined, followed by SGR, the maximal quantum yield of PSII (Fv Fm -1), and antioxidant activities. With an increasing Fe concentration in the substrate, the CAT and APX antioxidant levels decreased, which led to an increase in H2O2 accumulation in the plant tissues. Moreover, increased POD activity was proportionate to H2O2 accumulation, suggesting the low-Fe independent nature of POD. Diurnally, H2O2 concentration varies following the PAR variation. However, the CAT and APX antioxidant activities were delayed, which increased the H2O2 concentration level in the afternoon compared with the level in morning for the same PAR intensities. Similar trends were also obtained for the natural river samples where relatively low light intensity was preferable for growth. Together with our previous findings on macrophyte stress responses, these results indicate that H2O2 concentration is a good indicator of environmental stressors and could be used instead of long-term growth monitoring in macrophyte management.

Elevated IL-37, IL-18 and IL-18BP serum concentrations in patients with primary Sjögren's syndrome.

The objectives of this study were to examine the serum levels of interleukin (IL)-37 and its clinical association in patients with primary Sjögren's syndrome (pSS) and to investigate whether or not IL-37 participates in the regulation of the pathogenesis of pSS. ELISA was used to analyse the serum levels of IL-37, total IL-18 and IL-18 binding protein (IL-18BP). The level of free IL-18 was calculated based on the mass action law. The correlations between the IL-37 serum levels with the laboratory values and the total IL-18 and IL-18BP serum levels were analyzed by a Spearman's correlation test. The serum levels of IL-37 in the patients with pSS were significantly increased compared with the healthy controls (HCs). The levels were especially elevated in the patients with pSS with positive anti-Ro/SSA and/or anti-La/SSB antibodies. Furthermore, the patients with pSS showed high serum levels of total IL-18, free IL-18 and IL-18BP compared with the HCs. Strikingly, the IL-37 levels were significantly positively correlated with the antibody levels in the patients with pSS, including rheumatoid factor, anti-Ro/SSA, and anti-La/SSB and the total IL-18 and IL-18BP serum levels. The serum levels of IL-37, which were correlated with antibody production and the serum levels of total IL-18 and IL-18BP, were elevated in the patients with pSS. IL-37, an important anti-inflammatory cytokine, may participate in the regulation of the pathogenesis of pSS.