环境科学与生态学最新文献

Perfluorononanoic acid (PFNA) is a perfluoroalkyl acid containing nine carbon chains, with an additional carbon‑fluorine bond that makes it more stable and toxic. Studies have shown that PFNA can harm the reproductive, immune, and nervous systems, as well as many organs, which can increase the risk of cancer. In this study, zebrafish embryos were treated with 0 and 100 μM PFNA for 72 and 96 hpf, and their angiogenesis and haematopoiesis were observed under laser confocal microscopy using Tg (fli1:EGFP) and Tg (gata1:DsRed) transgenic zebrafish. The data showed that PFNA exposure decreased heart rate and slowed blood flow in zebrafish. PFNA was found to inhibit erythropoiesis by O-dianisidine staining. RNA-seq analysis was used to compare gene expression changes in zebrafish from control and 100 μM PFNA-exposed groups at 72 hpf. KEGG results showed significant enrichment of PPAR signaling pathway, fatty acid metabolism, steroid biosynthesis and apoptosis. The RNA-seq results were validated by real-time fluorescence quantitative PCR (RT-qPCR). Oil red O staining and Filipin staining showed increased lipid accumulation after PFNA exposure, and TUNEL staining showed that PFNA exposure led to apoptosis. In conclusion, exposure to PFNA may cause toxic effects in zebrafish by affecting cardiovascular development, causing lipid accumulation and promoting apoptosis.

Lake management actions are required to protect lake ecosystems that are being threatened by climate change. Freshwater lakes in semiarid regions are of upmost importance to their region. Simulations of the subtropical Lake Kinneret project that rising temperatures will cause change to phytoplankton species composition, including increased cyanobacteria blooms, endangering lake ecosystem services. Using lake ecosystem models, we examined several management actions under climate change, including two alternatives of desalinated water introduction into the lake, hypolimnetic water withdrawal, watershed management changes and low versus high lake water level. To account for prediction uncertainty, we utilized an ensemble of two 1D hydrodynamic-biogeochemical lake models along with 500 realizations of meteorological conditions. Results suggest that supplying desalinated water for local use, thus releasing more natural waters through the Jordan River, increasing nutrient flow, may reduce cyanobacteria blooms, mitigating climate change effects. However, these results are accompanied by considerable uncertainty.

The interplay of climate change, upstream hydropower development, and local water engineering interventions for agricultural production contributes substantially to the transformation of waterscapes and water scarcity in the Vietnamese Mekong Delta. This paper aims to examine how these dynamics are linked to the paradigm shift in water management in An Giang and Ben Tre, the two ecologically distinct provinces that face serious water scarcity in the delta. We used the adaptive management concept to examine how state-led policy directions from food security towards water security enable change in water management that gives priority to water retention. While policy learning is evident, questions remain about how this ad-hoc solution could help address the presently acute water scarcity and water security over the long term. The paper advocates achieving water security should focus not only on diplomatic interventions into upstream climate-development complexities but also local water-livelihood politics.

In this perspective, we present and discuss four major causes of the worldwide nature conservation failure: 1) ideologies based on nature-culture dualism, 2) the bias prioritising forests in conservation, 3) the illusory objectiveness of selected biological indicators, and 4) the mismanagement of rural agricultural landscapes. All of these relate to ignorance of historical ecology and neglect of the role past plays in shaping landscapes and fostering biodiversity. These led to a false anthropology focussed on the broader human economy (including agriculture) as the absolute culprit of biodiversity loss. It is believed, therefore, that biodiversity preservation depends on conservation policies and actions providing protection against human activities, such as farming. In this way, nature conservation has been detached from the rich experiences of long and fruitful coexistence of people with other elements of nature. The bio-cultural legacy includes biodiversity-rich rural landscapes, whose habitats are often either neglected or wrongly interpreted as "remnants of natural ecosystems". Consequently, conservation efforts are frequently ineffective or worse still, counter-effective. In the face of policies favouring subsidised intensive agribusiness at the cost of destroying smallholder family farming, even expensive conservation projects are usually nothing more than a "fig leaf" to cover failure. We advocate re-focussing of conservation planning to put more emphasis on landscapes' historical ecology responsible for their bio-cultural diversity. It implies the need for new principles in policies necessary to secure the economic and cultural sovereignty of local socio-ecological systems responsible for the world's bio-cultural diversity.

Glyphosate, a pesticide commonly found in aquatic ecosystems, affects this habitat and nontarget organisms such as fish. The increase in water temperature, linked to factors such as climate change, poses a considerable threat. Despite extensive ecotoxicological research, we still do not know the real individual and specific consequences of continued exposure to glyphosate and high temperatures, simulating a scenario where the aquatic environment remains contaminated and temperatures continue to rise. Therefore, in this study, we examined the effects of exposure to environmentally relevant concentrations of glyphosate, active ingredient glyphosate (GAI), and glyphosate-based herbicide (GBH) in combination with high temperature (34 °C) in adult zebrafish (Danio rerio). The fish were acclimated to 28 or 34 °C for 96 h. The exposure to 225 and 450 μg L^-1 (GBH or GAI) at 28 or 34 °C for 7 days. We analyzed behavioral endpoints (anxiety-like response, sociability, and aggressivity) and biochemical biomarkers of the brain and muscle (oxidative stress). Anxiety-like responses and decreased sociability were disrupted by the combination of glyphosate and high temperature. Furthermore, there is a decrease in Acetylcholinesterase activity in the brain, and an increase in Lipid Peroxidation, Protein Carbonylation, Acetylcholinesterase activity, and Glutathione S-Transferase activity in the muscle. These results demonstrated oxidative stress, anxiety-like behavior and decreased sociability caused by glyphosate and high temperature. We concluded that the combined effects of glyphosate and high temperature affected redox homeostasis and behavior, emphasizing that the field of glyphosate pollution should be carefully considered when evaluating the effects of climate change.

Numerous environmental pollutants exhibit ototoxicity and cause damage to the lateral line structures in fish, including the neuromast and its hair cells. The lateral line is used to detect hydrodynamic changes and is thought to play a significant role in aggressive interactions. Fighting behaviors in fish are crucial for establishing social hierarchy and obtaining limited resources. In this study, we ablated the function of hair cells using a commonly used ototoxin, neomycin, to evaluate the impact of this ototoxic pollutant on fighting behavior through damaging the lateral line. Our results showed that the number of wins and the duration of dyadic fight behavior decreased in zebrafish with lateral line ablation. These zebrafish also exhibited increased anxiety and biting frequencies. On the other hand, social preferences and fitness were not affected in lateral line-ablated zebrafish. In conclusion, the lateral line mechanosensory system is crucial for fish to gather sufficient information and make correct decisions during conflicts and fighting behaviors. Impairment of hair cell function can affect aggressive behaviors and decision-making in fish, subtly altering their behavioral patterns and leading to significant impacts on the aquatic ecosystem.

Cathelicidin is a family of antimicrobial peptides in vertebrates that plays an important role in resistance and immunization against pathogenic microorganisms. In the present study, the full-length cDNA sequences of four novel cathelicidins (cathelicidin-1 to cathelicidin-4) in the tiger frog Hoplobatrachus rugulosus, encoding 153, 188, 132, and 160 amino acids, respectively, were firstly cloned by rapid amplification of the cDNA ends (RACE) technique. Sequence comparison and phylogenetic tree analysis indicated that the structures of the four cathelicidins are highly diverse. Afterwards, the tissue distribution profiles and antimicrobial patterns of cathelicidins in H. rugulosus were determined by real-time PCR. The four cathelicidins showed tissue-specific distribution patterns in the healthy frogs, and the transcriptional levels of cathelicidins exhibited a tissue- and time-dependency profile in the frogs challenged with pathogenic bacteria Aeromonas hydrophila for 72 h. The synthetic peptides of cathelicidin-1 and cathelicidin-2 exhibited broad-spectrum in vitro antimicrobial activity, and cathelicidins exerted antimicrobial activities through excessive induction of reactive oxygen species and direct disruption of the microbial membrane structure. In addition, the intraperitoneal injection of cathelicidin proteins significantly increased the marine medaka Oryzias melastigma resistance to bacterial challenges. The existence of multiple cathelicidins, their distinct tissue distribution patterns, and the inducible expression profiles suggest a sophisticated, highly redundant, and multilevel network of antimicrobial defense mechanisms in tiger frogs. This study provides evidence that cathelicidins have antimicrobial and immunomodulatory activities, and cathelicidins derived from H. rugulosus have potential therapeutic applications against pathogenic infections in aquaculture.

Perfluorooctanesulfonic acid (PFOS) and sodium nitrite may have complex adverse effects on aquatic animals. This study assessed the interactive effects of PFOS and sodium nitrite on Chinese mitten crab (Eriocheir sinensis). A 2 × 3 factorial experiment with 0, 0.1, and 5 mg/L PFOS and 0, 3.50 mg/L sodium nitrite evaluated impacts on growth, behavior, oxygen consumption, health, energy metabolism, and hepatopancreas transcriptome. PFOS <0.1 mg/L with 3.50 mg/L nitrite significantly decreased PFOS accumulation in the hepatopancreas and improved feeding rates and hepatopancreas structure (P < 0.05). Under 5 mg/L PFOS and nitrite, survival, weight gain, hepatosomatic index, and feeding rate significantly decreased (P < 0.05). PFOS (0.1 mg/L) with nitrite significantly prolonged righting response time and increased locomotion speed (P < 0.05). PFOS (5 mg/L) significantly decreased serum triglyceride and lactate levels, while PFOS and nitrite decreased glucose, triglyceride, and glycogen levels and increased lactate in hepatopancreas (P < 0.05). Transcriptomic analysis indicated that PFOS affects p53 signaling, cell cycle and neurotransmission pathways, with notable changes in cell proliferation genes (pcna, ccna, cdk1, cdk2, rbx1) primarily downregulated by PFOS. Overall, PFOS disrupts neurotransmitter regulation and causes hepatopancreatic damage, while nitrite can reduce the toxicity of PFOS by decreasing its hepatopancreas accumulation. However, high levels of PFOS combined with sodium nitrite exacerbate toxicity, emphasizing the need for comprehensive assessment of environmental pollutant interactions.

It has been reported that enrofloxacin (ENR) disrupts metabolic pathway of steroid in female crucian carp, promoting testosterone (T) synthesis through stimulating expression of luteinizing hormone (LH) and inhibiting conversion of T to estradiol (E₂) through repressing aromatase A expression. To further learn effect of ENR on steroid metabolism in fish, this work investigated effect of ENR on central E₂ synthesis and the involved mechanisms in female crucian carp through evaluating contents of T and E₂ in blood and brain, expression of secretogranin 2a (scg2a), gonadotrophin 2 β (gth 2β, namely LH) and aromatase B (cyp19a1b) genes in brain, and activation of PI3K/Akt pathway in brain of ENR exposed female crucian carp. Results revealed that ENR promoted steroid metabolism in brain of female crucian carp, stimulated synthesis of T synthesis but inhibited conversion of T to E₂ through promoting expression of scg2a and gth 2β but repressing expression of cyp19a1b, PI3K/Akt signaling pathway participated in regulating the biological process.

As temperatures rise due to increasingly severe global warming, the effect of high temperatures on wildlife, including green sea turtles, is one of the issues that must be addressed to ensure the conservation of biodiversity. In the current study, we found that green sea turtle cell death due to apoptosis occurred at 37 °C, which suppressed cell proliferation. We also found that high temperature-induced heat stress led to the accumulation of DNA damage in green sea turtle cells. DNA damage is a key factor for the induction of apoptosis. Therefore, heat stress-mediated DNA damage can trigger green sea turtle cell apoptosis. Based on these results, we predict that high temperatures, such as 37 °C, would adversely impact green sea turtles, resulting in death or health-related challenges. Importantly, this information can facilitate the conservation of green sea turtles because cellular and molecular studies regarding the effects of global warming effects remain limited.