The extensive use of sulfonylurea herbicides has raised major concerns regarding their long-term soil residues and agroecological risks despite their role in agricultural protection. Microbial degradation is an important approach to remove sulfonylureas, whereas understanding the associated biodegradation mechanisms, enzymes, and physiological responses remains incomplete. Based on the rapid biodegradation of nicosulfuron by typical fungal isolate Talaromyces flavus LZM1, the dependency on cellular accumulation and environmental conditions, e.g. pH and nutrient supplies, was shown in the study. The biodegradation of nicosulfuron occurred intracellularly and followed the cascade of reactions including hydrolysis, Smile contraction rearrangement, hydroxylation, and opening of the pyrimidine ring. Besides 2-amino-4,6-dimethoxypyrimidine (ADMP) and 2-aminosulfonyl-N,N-dimethylnicotinamide (ASDM), numerous products and intermediates were newly identified and the structural forms of methoxypyrimidine and sulfonylurea bridge contraction rearrangement are predicted to be more toxic than nicosulfuron. The biodegradation should be enzymatically regulated by glycosylphosphatidylinositol transaminase (GPI-T) and P450s, which were manifested with the significant upregulation in proteomics. It is the first time that the hydrolysis of nicosulfuron into ADMP and ASDM have been associated with GPI-T. The integrated pathways of biodegradation were further elucidated through the involvement of various active enzymes. Except for the enzymatic catalysis, the physiological responses verified by metabolo-proteomics were critical not only to regulate material synthesis, uptake, utilization, and energy transfer but also to maintain antioxidant homeostasis, biodegradability, and tolerance of nicosulfuron by the differentially expressed metabolites, such as acetolactate synthase and 3-isopropylmalate dehydratase. The obtained results would help understand the biodegradation mechanism of sulfonylurea from chemicobiology and enzymology and promote the use of fungal biodegradation in pollution rehabilitation.

Red and far-red light-sensing phytochromes are widespread in nature, occurring in plants, algae, fungi, and prokaryotes. Despite at least a billion years of evolution, their photosensory modules remain structurally and functionally similar. Conversely, nature has found remarkably different ways of transmitting light signals from the photosensor to diverse physiological responses. We summarize key features of phytochrome structure and function and discuss how these are correlated, from how the bilin environment affects the chromophore to how light induces cellular signals. Recent advances in the structural characterization of bacterial and plant phytochromes have resulted in paradigm changes in phytochrome research that we discuss in the context of present-day knowledge. Finally, we highlight questions that remain to be answered and suggest some of the benefits of understanding phytochrome structure and function.

Antibiotic shock may potentially impact the performance of promising microalgae-nitrifying bacteria consortia (MNBC) processes. This study investigated physiological behaviors of MNBC under sulfamethoxazole (SMX) shock (mg/L level) and verified a light regulating strategy for improving process performance. Results showed that SMX shock did not affect ammonium removal but caused nitrite accumulation, resulting from combined effects of excessive reactive oxidative species (ROS) production, inhibited microalgal photosynthetic activity, upregulated expressions of amoA and hao, and downregulated expression of nxrA. Moreover, high ammonium concentration aggravated nitrite accumulation and reduced ammonium removal owing to significantly reduced dissolved oxygen (DO). Increasing light intensity enhanced microalgal photo-oxygenation and promoted expressions of all nitrification-related genes, thus improving ammonium removal and alleviating nitrite accumulation. A central composite design coupled with response surface methodology (CCD-RSM) further demonstrated the negative impacts of SMX shock and high ammonium on MNBC and the effectiveness of the light regulation in maintaining stable process performance. This study provides theoretical basis for physiological responses and regulatory strategy of the MNBC process facing short-term antibiotic shock.

Soil is home to microbiota with diverse metabolic activities. These microorganisms play vital roles in many ecological processes. Thus, the assessment of microbial functional diversity is an important quality indicator of soil ecosystems. In this study, we collected soil samples from three distinct forest habitats, i.e., an agroforest, a primary forest (PF), and a secondary forest, within the Angat Watershed Reservation in Bulacan, Northern Philippines. Community-level physiological profiling (CLPP) was done with the BIOLOG EcoPlate™ to analyze the responses of the soil microbial communities from the three forest habitats in the absence or presence of antibiotics. The BIOLOG EcoPlate represents 31 utilizable carbon sources. Based on the CLPP analysis, soil samples from the PF showed significantly higher utilization of most carbon sources than the other forest types (p < 0.05). Thus, less disturbed forest types constitute more functionally diverse microbial communities. The presence of antibiotics significantly decreased the carbon utilization patterns of the soil microbial communities (p < 0.05), indicating the possible use of CLPP in monitoring contamination in soil.

Seaweed cultivation can inhibit the occurrence of red tides. However, how seaweed aquaculture interactions with harmful algal blooms will be affected by the increasing occurrence and intensity of marine heatwaves (MHWs) is unknown. In this study, we run both monoculture and coculture systems to investigate the effects of a simulated heatwave on the competition of the economically important macroalga Gracilariopsis lemaneiformis against the harmful bloom diatom Skeletonema costatum. Coculture with G. lemaneiformis led to a growth decrease in S. costatum. Growth and photosynthetic activity (Fv/Fm) of G. lemaneiformis was greatly reduced by the heatwave treatment, and did not recover even after one week. Growth and photosynthetic activity of S. costatum was also reduced by the heatwave in coculture, but returned to normal during the recovery period. S. costatum also responded to the stressful environment by forming aggregates. Metabolomic analysis suggests that the negative effects on S. costatum were related to an allelochemical release from G. lemaneiformis. These findings show that MHWs may enhance the competitive advantages of S. costatum against G. lemaneiformis, leading to more severe harmful algal blooms in future extreme weather scenarios.

Hylurgus ligniperda invaded Shandong, China, through imported forest timber, posing a threat to China\'s forest health. Exotic insects with broad environmental tolerance, including low temperatures, may have a better chance of surviving the winters and becoming invasive. Understanding the cold-tolerance strategies of H. ligniperda may help to design sustainable pest management approaches. In this study, we aim to investigate the cold-tolerance ability and relevant physiological indicators in overwintering H. ligniperda adults to determine any possible overwintering strategies. Supercooling points (SCPs) for adults H. ligniperda differed significantly across months and reached the lowest level in the mid- and post-overwintering period, the minimum SCPs -6.45 ± 0.18 °C. As the cold exposure temperature decreased, the survival rate of adults gradually decreased, and no adult survived more than 1 day at -15 °C, and the LLT50 for 1 day was -7.1 °C. Since H. ligniperda adults can survive internal ice formation, they are freeze-tolerant insects. Throughout the overwintering period, the SCPs and the water, protein, sorbitol, and glycerol content in adults decreased initially and then increased. We reported significant correlations between total protein, sorbitol, trehalose, and glycerol content in the beetles and SCPs. Glycogen, lipid, protein, trehalose, and sorbitol content in adult beetles may directly affect their cold-tolerance capacity and survival during winter. This study provides a physiological and biochemical basis for further study of metabolism and cold-tolerance strategies in H. ligniperda adults, which may help predict population dynamics and distribution potential of pests.

Flooding stress is an increasingly serious problem in wetlands, often affecting large areas of crops and timber production areas. The current study aimed to explore the species differences in responses to flooding stress between Q. nuttallii and Q. palustris in an outdoor environment. All the tested plants survived after a 60-day flooding treatment that left 5 cm of water above the soil surface. This suggests that the two species are flood-tolerant, so they can be applied in the construction of riparian protection forests and wetland restoration. Compared with control conditions, flooding treatment significantly decreased seedling height and diameter and the Pn, Gs, Tr, Fv/Fm, ABS/CSm, TR0/CSm, ET0/CSm, RE0/CSm, IAA, and GA3 content and significantly increased the content of MDA, H2O2, soluble sugars, SOD, POD, ADH, ABA, and JA. Under control conditions, Q. nuttallii showed significantly greater growth and photosynthetic capability than Q. palustris. In contrast, Q. palustris exhibited less inhibition of growth and photosynthesis, oxidative stress levels, and antioxidant enzyme activities than Q. nuttallii under flooding conditions. The findings indicate that Q. palustris has better defense mechanisms against the damage caused by flooding stress than Q. nuttallii. Q. nuttallii was more sensitive and responsive to flooding than Q. palustris.

UV-B is an important environmental factor that differentially affects plant growth and secondary metabolites. The effects of supplemental ultraviolet-B (sUV-B) exposure (T1, 1.40 kJ·m-2·day-1; T2, 2.81 kJ·m-2·day-1; and T3, 5.62 kJ·m-2·day-1) on the growth biomass, physiological characteristics, and secondary metabolites were studied. Our results indicated that leaf thickness was significantly (p < 0.05) reduced under T3 relative to the control (natural light exposure, CK); The contents of 6-BA and IAA were significantly reduced (p < 0.05); and the contents of ABA, 10-deacetylbaccatin III, and baccatin III were significantly (p < 0.05) increased under T1 and T2. The paclitaxel content was the highest (0.036 ± 0.0018 mg·g-1) under T3. The cephalomannine content was significantly increased under T1. Hmgr gene expression was upregulated under T1 and T3. The gene expressions of Bapt and Dbtnbt were significantly (p < 0.05) upregulated under sUV-B exposure, and the gene expressions of CoA, Ts, and Dbat were significantly (p < 0.05) downregulated. A correlation analysis showed that the 6-BA content had a significantly (p < 0.05) positive correlation with Dbat gene expression. The IAA content had a significantly (p < 0.05) positive correlation with the gene expression of Hmgr, CoA, Ts, and Dbtnbt. The ABA content had a significantly (p < 0.05) positive correlation with Bapt gene expression. Dbat gene expression had a significantly (p < 0.05) positive correlation with the 10-deacetylbaccatin content. Hmgr gene expression was positively correlated with the contents of baccatin III and cephalomannine. Bapt gene expression had a significantly (p < 0.01) positive correlation with the paclitaxel content. A factor analysis showed that the accumulation of paclitaxel content was promoted under T2, which was helpful in clarifying the accumulation of taxane compounds after sUV-B exposure.

Hypoxia is a globally pressing environmental problem in aquatic ecosystems. In the present study, a comprehensive analysis was performed to evaluate the effects of hypoxia on physiological responses (hematology, cortisol, biochemistry, hif gene expression and the HIF pathway) of hybrid sturgeons (Acipenser schrenckii ♂ × Acipenser baerii ♀). A total of 180 hybrid sturgeon adults were exposed to dissolved oxygen (DO) levels of 7.00 ± 0.2 mg/L (control, N), 3.5 ± 0.2 mg/L (moderate hypoxia, MH) or 1.00 ± 0.1 mg/L (severe hypoxia, SH) and were sampled at 1 h, 6 h and 24 h after hypoxia. The results showed that the red blood cell (RBC) counts and the hemoglobin (HGB) concentration were significantly increased 6 h and 24 h after hypoxia in the SH group. The serum cortisol concentrations gradually increased with the decrease in the DO levels. Moreover, several serum biochemical parameters (AST, AKP, HBDB, LDH, GLU, TP and T-Bil) were significantly altered at 24 h in the SH group. The HIFs are transcription activators that function as master regulators in hypoxia. In this study, a complete set of six hif genes were identified and characterized in hybrid sturgeon for the first time. After hypoxia, five out of six sturgeon hif genes were significantly differentially expressed in gills, especially hif-1α and hif-3α, with more than 20-fold changes, suggesting their important roles in adaptation to hypoxia in hybrid sturgeon. A meta-analysis indicated that the HIF pathway, a major pathway for adaptation to hypoxic environments, was activated in the liver of the hybrid sturgeon 24 h after the hypoxia challenge. Our study demonstrated that hypoxia, particularly severe hypoxia (1.00 ± 0.1 mg/L), could cause considerable stress for the hybrid sturgeon. These results shed light on their adaptive mechanisms and potential biomarkers for hypoxia tolerance, aiding in aquaculture and conservation efforts.

Selenium (Se) is crucial for both plants and humans, with plants acting as the main source for human Se intake. In plants, moderate Se enhances growth and increases stress resistance, whereas excessive Se leads to toxicity. The physiological mechanisms by which Se influences rice seedlings\' growth are poorly understood and require additional research. In order to study the effects of selenium stress on rice seedlings, plant phenotype analysis, root scanning, metal ion content determination, physiological response index determination, hormone level determination, quantitative PCR (qPCR), and other methods were used. Our findings indicated that sodium selenite had dual effects on rice seedling growth under hydroponic conditions. At low concentrations, Se treatment promotes rice seedling growth by enhancing biomass, root length, and antioxidant capacity. Conversely, high concentrations of sodium selenite impair and damage rice, as evidenced by leaf yellowing, reduced chlorophyll content, decreased biomass, and stunted growth. Elevated Se levels also significantly affect antioxidase activities and the levels of proline, malondialdehyde, metal ions, and various phytohormones and selenium metabolism, ion transport, and antioxidant genes in rice. The adverse effects of high Se concentrations may directly disrupt protein synthesis or indirectly induce oxidative stress by altering the absorption and synthesis of other compounds. This study aims to elucidate the physiological responses of rice to Se toxicity stress and lay the groundwork for the development of Se-enriched rice varieties.