Alterations in hematological and biochemical parameters, oxidative stress, and immune response in Takifugu rubripes under acute ammonia exposure.

Ammonia is a major pollutant in aquatic environments and poses a considerable threat to the survival of fish. In this study, we investigated the toxic effects of ammonia on the hematological and biochemical parameters, oxidative stress, and immune responses in Takifugu rubripes. Juvenile T. rubripes (average weight 246.17 ± 3.54 g) were exposed to different concentrations of ammonia (0, 5, 50, 100, and 150 mg/L) for 96 h. The results showed that the hematological parameters (hemoglobin, hematocrit, red blood cell, and white blood cell count) were significantly reduced in response to ammonia exposure. Of the plasma components, such as serum total protein, albumin, glucose, glutamic-oxalacetic transaminase, and glutamic-pyruvic transaminase, were significantly altered in response to ammonia exposure. Additionally, the levels of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GPx) were increased after exposure to low concentration ammonia exposure. However, when fish were exposed to a high concentration of ammonia, these parameters showed the opposite trend, suggesting that an increase in antioxidant enzymes during the early stages of ammonia exposure may contribute to the removal of the induced reactive oxygen species (ROS) and protect the cells from oxidative damage. However, as the ammonia concentration and exposure time increased, the overproduction of ROS accelerated the depletion of antioxidant enzymes. Ammonia exposure significantly increased the expression of heat shock proteins (HSP70 and HSP90). Ammonia poisoning elevated gene expressions of TLR-3, TNF-α, IL-6, IL-12, and IL-1ß in the gills, causing an inflammatory response. Our findings provide new insights into the mechanisms involved in ammonia-induced aquatic toxicology in marine fish, which may aid in their captive management.

Impact of nitrite exposure on plasma biochemical parameters and immune-related responses in Takifugu rubripes.

Nitrite is a major environmental pollutant in aquatic environments that negatively affects aquatic species. In this study, we investigated the impact of nitrite exposure on plasma biochemical parameters and immune responses in Takifugu rubripes. Fish were exposed to various concentrations of nitrite (0, 0.5, 1, 3, and 6 mM) for 96 h. After 0, 12, 24, 48, and 96 h of exposure, fish blood samples were collected to assay the levels of total protein (TP), albumin (Alb), glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (ALT), complement C3 (C3), complement C4 (C4), immunoglobulin (IgM), and lysozyme activity (LZM). The gills were sampled to analyze the mRNA levels of heat shock protein 70 (hsp70), heat shock protein 90 (hsp90), tumor necrosis factor α (tnf-α), B-cell activating factor (baff), interleukin-6 (il-6), and interleukin-12 (il-12). Levels of GOT, ALT, C3, and C4 were significantly enhanced in the high nitrite concentration group (3 and 6 mM), whereas those of TP, Alb, LZM, and IgM decreased significantly with the same treatments. Nitrite significantly upregulated hsp70, hsp90, tnf-α, il-6, il-12, and baff mRNA levels after 96 h of exposure. These results indicated that nitrite exposure altered the blood physiological status and immune system response, resulting in dysfunction and immunotoxicity in T. rubripes. Furthermore, our results reveal the possible mechanism of aquatic-nitrite-induced toxicity in fish.

Effect of acute exposure to nitrite on physiological parameters, oxidative stress, and apoptosis in Takifugu rubripes.

In the present study, we evaluated the effects of nitrite exposure on hematological parameters, oxidative stress, and apoptosis in juvenile Takifugu rubripes. The fish were exposed to nitrite (0, 0.5, 1, 3, and 6 mM) for up to 96 h. In the high nitrite concentration groups (i.e., 3 and 6 mM), the concentrations of methemoglobin (MetHb), cortisol, glucose, heat shock protein (Hsp)-70, Hsp-90, and potassium (K+) were significantly elevated. Whereas, the concentrations of hemoglobin (Hb), triglyceride (TG), total cholesterol (TC), and sodium (Na+) and chloride (Cl-) ions were significantly decreased. Compared with those of the control groups, the concentrations of the antioxidant enzymes, namely, superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GPx), in the gills were considerably elevated at 12 and 24 h after exposure to nitrite (1, 3, and 6 mM), but reduced at 48 and 96 h. The increase in the antioxidant enzymes may contribute to the elimination of reactive oxygen species (ROS) induced by nitrite during early nitrite exposure, when the antioxidant system is not sufficiently effective to eliminate or neutralize excessive ROS. In addition, we found that nitrite exposure could alter the expression patterns of some key apoptosis-related genes (Caspase-3, Caspase-8, Caspase-9, p53, Bax, and Bcl-2). This indicated that the caspase-dependent apoptotic pathway and p53-Bax-Bcl-2 pathway might be involved in apoptosis induced by nitrite exposure. Furthermore, our study provides insights into how acute nitrite exposure affects the physiological responses and potential molecular mechanism of apoptosis in marine fish. The results can help elucidate the mechanisms involved in nitrite-induced aquatic toxicology in marine fish.

Exposure to nitrite alters thyroid hormone levels and morphology in Takifugu rubripes.

Nitrite (NO2-) can act as a toxic nitrogenous compound with the potential to disrupt endocrine systems in fish. The aim of the present study was to investigate the effects of nitrite on the thyroid endocrine system of Takifugu rubripes. Fish were exposed to 0, 0.5, 1, 3, and 6 mM nitrite concentrations. Blood was collected to assay the concentrations of thyroid-stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), free thyroxine (FT4), free triiodothyronine (FT3), and 3,3,5'-triiodothyronine (rT3), as well as the activity of iodothyronine deiodinases (Dio1, Dio2, and Dio3,) after 0, 12, 24, 48, and 96 h of exposure to nitrite. The first branchial arch to the third branchial arch of T. rubripes were sampled and fixed, and thyroid morphology was observed. The results showed that exposure to nitrite significantly increased the concentrations of TSH, T3, FT3, and reduced the concentrations of T4, FT4, and rT3. The activity of Dio1 and Dio2 increased significantly, whereas Dio3 activity decreased significantly. Additionally, thyroid follicles degenerated and became blurred and most colloid material disappeared 96 h after exposure to high nitrite concentrations. Based on these results, high nitrite concentration exposure can disturb thyroid hormone homeostasis, alter thyroid follicle morphology, and result in thyroid endocrine toxicity.

[Species composition, distribution and phenological characters of pollen-allergenic plants in Beijing urban area].

In order to know the species composition, distribution pattern, and phenological characteristics of pollen-allergenic plants in Beijing urban area, an investigation was made, combined with literature survey and experts interviews. The results showed that within the fifth ring of Beijing, there were 99 pollen-allergenic plant species belonging to 32 genera and 19 families, among which, 52 species were native plants, accounting for 52.5% of the total, 26 species were introduced from other regions of China, occupying 26.3% of the total, and 21 species were introduced from foreign countries, being 21.2% of the total. The 32 genera of pollen-allergenic plants in Beijing urban area were mainly North Temperate elements, occupying 40.6% , followed by Cosmopolitan and Pantropic elements. In all functional sections of Beijing urban area, the pollen-allergenic plants were most diversified in urban parks, and had the highest proportion in street tree species. The coverage of herbs with strong pollen allergy was in the order of waste lands > gym centers and institution yards > greenbelts > parks > residential areas > squares. The blooming period of pollen-allergenic arbors in Beijing urban area was concentrated in March and April, while that of pollen-allergenic herbs was from July to September.