A novel fluorescent sensor for evaluating pH changes in organophosphorus pesticides-treated cells and C. elegans.

pH plays an important role in the evaluation of the healthy status in versatile circumstances. The fluctuation of pH could be affected by complex internal and external stimuli. Especially, the abnormal pH changes is a common characteristic of organophosphorus pesticides (OPs)-caused damage owing to the irreversible inhibition of acetylcholinesterase (AChE) activity. Therefore, the rapid and efficient detection of pH changes is of great significance for predicting the OPs poisoning in living system. However, quick and convenient detecting pH levels in living cells is still limited by the lack of effective chemical tools. Here, a novel fluorescent probe TH-1 based on ESIPT mechanism was synthesized, showing specific fluorescent effects in different pH solutions. Importantly, the AChE catalyzed the hydrolysis product of acetylthiocholine iodide (ATCh) and changed the pH of solution, which influence its fluorescent intensity. Moreover, the probe TH-1 was applied to detecting the pH levels in living cells and C. elegans, providing an efficient chemical sensor for revealing the potential mechanisms of OPs in physiological and pathological processes.

Dynamic organic crystals as exceptionally efficient artificial natural light-harvesting actuators.

Dynamic organic crystal materials that can directly convert solar energy into mechanical work hold the potential to be efficient artificial actuators. However, developing dynamic organic crystals that can efficiently transform natural light energy into mechanical energy is still quite challenging. Herein, a novel dynamic organic crystal whose two polymorphs (Form I and Form II) are both capable of effectively converting natural light into work was successfully synthesized. Under the irradiation of ultraviolet (UV), blue and natural light, the on/off toggling of a photosalient effect could be triggered. Specifically, under UV light irradiation, Form I demonstrates output work densities of about 4.2-8.4 × 104 J m-3 and 1.6-4.9 × 102 J m-3 before and after disintegration, respectively. Form II exhibits output work densities of about 1.3 × 102 to 1.9 × 103 J m-3 by means of photoinduced bending, suggesting that controllable bending may be more favorable for energy harvesting than the photosalient effect. Utilizing the exceptionally high energy transduction efficiency of Form I, we developed a natural light-driven micro-actuator that can realize output work densities of 2.8-5.0 × 104 J m-3. The natural light-harvesting performance of this actuator significantly surpasses those of previously reported photomechanical crystals and could even be comparable to thermal actuators.

SlLTPg1, a tomato lipid transfer protein, positively regulates in response to biotic stresses.

Late blight, caused by Phytophthora infestans (P. infestans), is among the most devastating diseases affecting tomato and other Solanaceae species. Lipid transfer proteins (LTPs) represent a class of small, basic proteins that play a crucial role in combating biotic stresses. Previous studies have shown that SlLTPg1 most strongly responds after P. infestans infestation among the LTPs family in tomato. However, the function of SlLTPg1 in disease resistance remains unclear. Here, we constructed transient overexpression and VIGS-silenced plants of SlLTPg1. Our results revealed that SlLTPg1 plays a regulatory role in enhancing tomato resistance against P. infestans. This enhancement was attributed to the upregulation of defense-related genes and reactive oxygen species (ROS) scavenging genes, as well as increased enzymatic antioxidant activities. Importantly, we found that the SlLTPg1 protein significantly inhibited the growth of Fusarium oxysporum (F. oxysporum) by observing the zone of inhibition. Interestingly, we found smaller lesion diameters and upregulated expression levels of PR genes in transient overexpression SlLTPg1 of tobacco. Therefore, we further constructed transgenic tobacco lines of SlLTPg1, presenting evidence that overexpression of SlLTPg1 could positively regulate the resistance of tobacco to F. oxysporum. These findings revealed the role of SlLTPg1 in tomato resistance to P. infestans and tobacco resistance to F. oxysporum. Moreover, we propose SlLTPg1 as a potential candidate gene for augmenting broad-spectrum plant resistance against pathogens.

Regulatory Peptide Encoded by the Primary Transcript of miR396a Influences Gene Expression and Root Development in Solanum lycopersicum.

MicroRNAs (miRNAs) are the processing products of primary miRNAs (pri-miRNAs) that regulate the expression of target genes. Recent studies have demonstrated that some pri-miRNAs can encode small peptides (miPEPs) that perform significant biological functions. The function of miPEPs in tomatoes, an important model horticultural crop, remains to be investigated. Here, we characterized the primary sequence of tomato miR396a using 5' RACE and confirmed the presence of miPEP396a in tomato by verifying the translational activity of the start codon. It primarily resides in the nucleus to exert its function and additionally regulates the expression of pri-miR396a, miR396a, and its target genes. Transcriptomic and metabolomic analyses showed that in vitro synthesis of miPEP396a significantly increased the expression of genes related to phenylpropanoid biosynthesis and hormones in tomato. Meanwhile, our in vitro application of miPEP396a in tomato significantly inhibited the elongation of tomato primary roots. In conclusion, our results indicate that miPEP396a regulates root growth in tomato by specifically promoting miR396a expression, provide insight into the function of miPEPs in tomato and potential applications.

Trimodal operation of a robust smart organic crystal.

We describe a dynamic crystalline material that integrates mechanical, thermal, and light modes of operation, with unusual robustness and resilience and a variety of both slow and fast kinematic effects that occur on very different time scales. In the mechanical mode of operation, crystals of this material are amenable to elastic deformation, and they can be reversibly morphed and even closed into a loop, sustaining strains of up to about 2.6%. Upon release of the external force, the crystals resume their original shape without any sign of damage, demonstrating outstanding elasticity. Application of torque results in plastic twisting for several rotations without damage, and the twisted crystal can still be bent elastically. The thermal mode of operation relies on switching the lattice at least several dozen times. The migration of the phase boundaries depends on the crystal habit. It can be precisely controlled by temperature, and it is accompanied by both slow and fast motions, including shear deformation and leaping. Parallel boundaries result in a thermomechanical effect, while non-parallel boundaries result in a thermosalient effect. Finally, the photochemical mode of operation is driven by isomerization and can be thermally reverted. The structure of the crystal can also be switched photochemically, and the generation of a bilayer induces rapid bending upon exposure to ultraviolet light, an effect that further diversifies the mechanical response of the material. The small structural changes, low-energy and weak intramolecular hydrogen bonds, and shear deformation, which could dissipate part of the elastic energy, are considered to be the decisive factors for the conservation of the long-range order and the extraordinary diversity in the response of this, and potentially many other dynamic crystalline materials.

Quantitative determination of amphetamine-type stimulants in sewage and urine by hybrid monolithic column solid-phase microextraction coupled with UPLC-QTRAP MS/MS.

A needle-solid-phase microextraction (SPME) method based on hybrid monolithic column (HMC) was proposed for simultaneous separation and extraction of seven amphetamine-type stimulants (ATSs) (amphetamine, methamphetamine, cathinone, methcathinone, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, and 3,4-methylenedioxyethylamphetamine), combining with ultra-performance liquid chromatography-triple quadrupole/linear ion trap mass spectrometer (UPLC-QTRAP MS/MS). Thiol functionalized HMC (T-HMC) showed high extraction efficiency and excellent elution results towards target analytes, among three kinds of single/bi-functionalized HMCs. Various parameters of SPME operation and analytical performance were investigated systematically. The adsorption mechanism of T-HMC to ATSs was also discussed and explained as a mixed mode of electrostatic and hydrophobic interactions. Under the optimum experimental conditions, the proposed T-HMC needle-SPME-UPLC-QTRAP MS/MS method was rapid and convenient with good accuracy, low sample consumption, high sensitivity and strong anti-interference ability. This method was successfully applied to quantitative determination of seven trace ATSs in complex sewage and urine samples. In view of abundant types of HMCs, the needle-SPME based on functional HMC also had the potential to selectively separating and enriching other tract new psychoactive substances in complex matrices, and could provide a reliable tool for drug monitoring, especially in applications for forensic analysis and drug abuse.

Effects of air environmental audit on reducing air pollutant emissions: evidence from China.

In order to mitigate air pollution, governments have implemented various active measures for air pollution prevention and control, among which the air environmental audit is an essential supervision initiative of air environmental regulation policy. This study aims to focus on and investigate the role of air environmental audit in national governance systems by collecting panel data on air environmental audits and air pollutant emissions from 261 prefecture-level cities across China between 2004 and 2018. Using difference-in-differences (DID) models, we empirically analyzed the policy effects of air environmental audits on reducing air pollutant emissions. The results indicate that air environmental audits have a significant impact on reducing air pollutant emissions, which is robust under multiple scenarios, including propensity score matching and placebo tests. The effect of air environmental audits varies significantly among different air pollutants, with the most significant and rapid effect observed on PM2.5 concentration, while industrial sulfur dioxide and industrial smoke (dust) emissions exhibit a time lag. Moreover, the promotion effect of air environmental audits on air pollution control displays strong heterogeneity based on local economic levels, initial environmental quality, and government competition. Therefore, it is of great significance to intensify the implementation of air environmental audits for air pollution control and to promote and improve the audit work according to pollutant classification and local conditions, thereby fully leveraging the audit's role and further improving air quality continuously.

Anodic ammonium oxidation in microbial electrolysis cell: Towards nitrogen removal in low C/N environment.

Biological nitrogen removal in low C/N environment is challenging in wastewater treatment for a long time. Autotrophic ammonium oxidation is promising due to the no need of carbon source addition, but alternative electron acceptors other than oxygen has to be widely investigated. Recently, microbial electrolysis cell (MEC), which applies a polarized inert electrode as the electron harvester, has been proved effective to oxidize ammonium with electroactive biofilm. That is, anodic microbes stimulated by exogenous low power can extract electron from ammonium and transfer electron to electrodes. This review aims to consolidate the recent advances in anodic ammonium oxidation in MEC. Various technologies based on different functional microbes and mechanisms of these processes are reviewed. Thereafter, the crucial factors influencing the ammonium oxidation technology are discussed. Challenges and prospects of anodic ammonium oxidation in ammonium-containing wastewater treatment are also proposed to provide valuable insights on the technologic reference and potential value of MEC in ammonium-containing wastewater treatment.

A Sustainable Road Transport Decarbonisation: The Scenario Analysis of New Energy Vehicle in China.

Due to the prosperous development of the economy, the emissions of carbon dioxide (CO2) and other greenhouse gases (GHGs) have intensified and attracted attention worldwide. China has set the "dual-carbon" aim to pursue sustainable development in the transport sector. Thus, this study created a generalised Bass model to forecast new energy vehicle (NEV) ownership by introducing a new factor, charging piles, to reflect the infrastructure effects. Using the improved model with the hypothesis of annual mileage, an empirical analysis was conducted with the subject of NEVs in China by using the NEV-related panel data from 2010 to 2020, and the forecast result is outstanding with a goodness-of-fit of 99.7%. With the forecasts, carbon emission reduction was calculated with a bottom-up method. To further discuss the pathway to achieve carbon neutrality in the transport sector of China, a scenario analysis was conducted with ideal, enhanced, and radical constraints. The results show that if all factors remain "as is" until 2050, China will be far from carbon neutrality. Thus, this paper proposes relevant policy implications to assist the government to obtain effective methods to assess carbon reduction benefits and find viable pathways to a sustainable road transport system.

Strigolactones positively regulate Verticillium wilt resistance in cotton via crosstalk with other hormones.

Verticillium wilt caused by Verticillium dahliae is a serious vascular disease in cotton (Gossypium spp.). V. dahliae induces the expression of the CAROTENOID CLEAVAGE DIOXYGENASE 7 (GauCCD7) gene involved in strigolactone (SL) biosynthesis in Gossypium australe, suggesting a role for SLs in Verticillium wilt resistance. We found that the SL analog rac-GR24 enhanced while the SL biosynthesis inhibitor TIS108 decreased cotton resistance to Verticillium wilt. Knock-down of GbCCD7 and GbCCD8b genes in island cotton (Gossypium barbadense) decreased resistance, whereas overexpression of GbCCD8b in upland cotton (Gossypium hirsutum) increased resistance to Verticillium wilt. Additionally, Arabidopsis (Arabidopsis thaliana) SL mutants defective in CCD7 and CCD8 putative orthologs were susceptible, whereas both Arabidopsis GbCCD7- and GbCCD8b-overexpressing plants were more resistant to Verticillium wilt than wild-type (WT) plants. Transcriptome analyses showed that several genes related to the jasmonic acid (JA)- and abscisic acid (ABA)-signaling pathways, such as MYELOCYTOMATOSIS 2 (GbMYC2) and ABA-INSENSITIVE 5, respectively, were upregulated in the roots of WT cotton plants in responses to rac-GR24 and V. dahliae infection but downregulated in the roots of both GbCCD7- and GbCCD8b-silenced cotton plants. Furthermore, GbMYC2 suppressed the expression of GbCCD7 and GbCCD8b by binding to their promoters, which might regulate the homeostasis of SLs in cotton through a negative feedback loop. We also found that GbCCD7- and GbCCD8b-silenced cotton plants were impaired in V. dahliae-induced reactive oxygen species (ROS) accumulation. Taken together, our results suggest that SLs positively regulate cotton resistance to Verticillium wilt through crosstalk with the JA- and ABA-signaling pathways and by inducing ROS accumulation.

Collectivist culture, environmental regulation and pollution emissions: evidence from China.

Collectivist culture serves as a significant cultural foundation in China. It could, to some extent, shape public attitudes toward the environment and thus influence the implementation of related policies. To examine this hypothesis, this study constructs the collectivist culture intensity index for 25 Chinese provinces spanning from 2010 to 2020. Through a fixed-effect model, we explore how the collectivist culture intensity affects pollution emissions in China. The empirical results indicate the significance of collectivism in enhancing emission reduction through environmental regulations. This conclusion remains robust even when excluding the impact of endogeneity concerns by adopting the instrumental variable approach. Heterogeneity analysis shows that collectivism is more effective in enhancing market-based environmental regulations rather than those driven by policies. Further mechanism analysis confirms that green innovation is a crucial pathway through which collectivism influences pollution emissions. These findings here will offer guidance to policymakers when formulating environmental policies for contexts with different regional cultures.

The Effect of Air Pollution Control Auditing on Reducing Carbon Emissions: Evidence from China.

Analyzing the carbon-emission-reduction mechanism from the perspective of air pollution control auditing is of great practical significance for China to implement the dual-carbon strategy. Based on the panel data of 30 Chinese provinces from 2004 to 2018, we examine whether and how the auditing of air pollution control has an impact on carbon emission reduction by using multiple regression method and the mediating analysis. Our analyses show that air pollution control auditing can significantly restrain carbon emissions but has no impact on carbon emission intensity. Further research suggests that (1) the bottom-up audit represented by local audit institutions is more effective than the top-down audit represented by the National Audit Office; (2) air pollution control auditing follows a simple and direct method to curb carbon emissions by output reduction, regulation, and shutdown, rather than promoting technological progress and green transformation of enterprises in a high-quality development mode. Those findings provide an improvement direction for air pollution control auditing to contribute to carbon emission reduction and supply relevant policy references for implementing the dual carbon strategy.

Insight of bacteria and archaea in Feammox community enriched from different soils.

Anaerobic ammonium oxidation coupled to Fe(III) reduction, known as Feammox, is a newly discovered nitrogen-cycling process, which serves an important role in the pathways of nitrogen loss in the environment. However, the specific types of microorganisms involved in Feammox currently remain unclear. In this study, we selected two groups of soil samples (paddy and mine), from considerably different habitats in South China, to acclimate Feammox colonies. The Paddy Group had a shorter lag period than the Mine Group, while the ammonium transformation rate was nearly equal in both groups in the mature period. The emergence of the Feammox activity was found to be associated with the increased abundance of iron-reducing bacteria, especially Clostridium_sensu_stricto_12, Desulfitobacterium, Thermoanaerobaculum, Anaeromyxobacter and Geobacter. Ammonium oxidizing archaea and methanogens were dominant among the known archaea. These findings extend our knowledge of the microbial community composition of the potential Feammox microbes from soils under different environmental conditions, which broadens our understanding of this important Fe/N transformation process.

A promising destiny for Feammox: From biogeochemical ammonium oxidation to wastewater treatment.

Ammonium is one of the most common forms of nitrogen that exists in wastewater, and it can cause severe pollution when it is discharged without treatment. New technologies must be developed to effectively remove ammonium because conventional nitrification-denitrification methods are limited by the lack of organic carbon. Anaerobic ammonium oxidation coupled to Fe(III) reduction is known as Feammox, and is a recently discovered nitrogen cycling process. Feammox can proceed under autotrophic or anaerobic conditions and effectively transforms ammonium to stable, innocuous dinitrogen gas, using the ferric iron as an electron acceptor. This method is cost-effective, environmentally friendly, and conducive to joint application with other nitrogen removal reactions in low-C/N municipal wastewater treatments. This review provides a comprehensive survey of Feammox mechanistic investigations and presents studies regarding the functional microorganism colonies. The potential for Feammox to be applied for the removal of nitrogen from various polluted water sources and the combination of the Feammox process with other frontier environmental technologies are also discussed. In addition, future perspectives for removing ammonium using Feammox are presented.

Hot Deformation Behavior of Homogenized Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr Alloy via Hot Compression Tests.

Mg-Gd-Y-Zn-Zr Mg alloys show excellent performance in high-end manufacturing due to its strength, hardness and corrosion resistance. However, the hot deformation and dynamic recrystallization (DRX) behaviors of Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr were not studied. For this article, hot compression behavior of homogenized high rare-earth (RE) content Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr (wt%) alloy was investigated by using the Gleeble-3500D thermo-simulation test machine under the temperature of 350⁻500 °C and the strain rate of 0.001⁻1 s-1. It was found that the high flow stress corresponded to the low temperature and high strain rate, which showed DRX steady state curve during the hot compression. The hot deformation average activation was 263.17 kJ/mol, which was obtained by the analysis of the hyperbolic constitutive equation and the Zener-Hollomon parameter. From observation of the microstructure, it was found that kink deformation of long period stacking ordered (LPSO) phase was one of the important coordination mechanisms of hot deformation at low temperature. The processing map with the strain of 0.5 was established under the basis of dynamic material model (DMM); it described two high power dissipation domains: one appearing in the temperature range of 370⁻440 °C and the strain rate range of 0.001⁻0.006 s-1, the other appearing in the temperature range of 465⁻500 °C and strain rate range of 0.001⁻0.05 s-1, in which dynamic recrystallization (DRX) mainly ocurred. The highest degree of DRX was 18% from the observation of the metallographic.

Effect of high-salt diet on vascular relaxation and oxidative stress in mesenteric resistance arteries.

This study tested the hypothesis that superoxide levels are elevated in isolated mesenteric resistance arteries (100-300 microm) from rats fed a short-term high-salt (HS) diet (4% NaCl for 3 days) compared to controls fed a low-salt (LS) diet (0.4% NaCl). Vascular relaxation induced by the superoxide dismutase mimetic tempol (4-hydroxytetramethylpiperidine-1-oxyl), the NADPH oxidase inhibitor apocynin and the xanthine/xanthine oxidase inhibitor oxypurinol was significantly larger in mesenteric arteries from animals fed HS diet compared to arteries from animals fed LS diet. Basal superoxide levels assessed via dihydroethidine (DHE) fluorescence were significantly elevated in arteries from rats fed HS diet, and were reduced by tempol, apocynin and oxypurinol, but not by L-NAME. Basal and methacholine-induced NO production (assessed by DAF-2T fluorescence) was significantly reduced in arteries from rats fed HS diet versus arteries from rats on LS diet. Impaired methacholine-induced NO release and vascular relaxation were restored by tempol and apocynin, but not by oxypurinol. These data suggest that the elevated production of superoxide by NADPH oxidase and xanthine/xanthine oxidase contribute to elevated basal superoxide levels, reduced NO release and impaired vascular relaxation in mesenteric resistance arteries of rats fed HS diet.

TNF-alpha-induced impairment of mitochondrial integrity and apoptosis mediated by caspase-8 in adult ventricular myocytes.

Tumor necrosis factor (TNF)-alpha has been shown to induce apoptosis in a variety of cell types including cardiac myocytes. Sphingosine/ceramide and nitric oxide have been associated with apoptosis induced by TNF-alpha; however, signaling mechanisms of TNF-alpha-induced apoptosis in cardiac myocytes are not well defined. This study examined whether alterations in mitochondrial integrity are involved in TNF-alpha-induced apoptosis in adult ventricular myocytes (ARVM) and determined the roles of caspase-8 (an upstream mediator of TNF-alpha receptor-associated signaling) in this process. After incubation for 24-48 h in serum-free culture medium, ARVM underwent spontaneous apoptosis, which remained stable and was not affected by Z-IETD-FMK, a selective caspase-8 inhibitor. Meanwhile, exposure to TNF-alpha resulted in an increase in apoptosis that was detectable at 6 h and became significant after 12 h, when compared to time-controls. After 24-h exposure, TNF-alpha increased caspase-8 activities, mitochondrial cytochrome C (Cyt C) release to the cytosol, accompanied by loss of mitochondrial transmembrane potential (delta psi(m)). Inhibition of caspase-8 activation in the presence of Z-IETD-FMK abolished the TNF-alpha-induced increases in mitochondrial Cyt C release, loss of delta psi(m) and apoptosis. Therefore, these results suggest that TNF-alpha-induced increase in apoptosis in ARVM results from caspase-8-dependent impairment of mitochondrial integrity.

Role of superoxide and angiotensin II suppression in salt-induced changes in endothelial Ca2+ signaling and NO production in rat aorta.

Male Sprague-Dawley rats were maintained on a low-salt (LS) diet (0.4% NaCl) or changed to a high-salt (HS) diet (4% NaCl) for 3 days. Increases in intracellular Ca2+ ([Ca2+]i) in response to methacholine (10 microM) and histamine (10 microM) were significantly attenuated in aortic endothelial cells from rats fed a HS diet, whereas thapsigargin (10 microM)-induced increases in [Ca2+]i were unaffected. Methacholine-induced nitric oxide (NO) production was eliminated in endothelial cells of aortas from rats fed a HS diet. Low-dose ANG II infusion (5 ng x kg(-1) x min(-1) iv) for 3 days prevented impaired [Ca2+]i signaling response to methacholine and histamine and restored methacholine-induced NO production in aortas from rats on a HS diet. Adding Tempol (500 microM) to the tissue bath to scavenge superoxide anions increased NO release and caused N(omega)-nitro-L-arginine methyl ester-sensitive vascular relaxation in aortas from rats fed a HS diet but had no effect on methacholine-induced Ca2+ responses. Chronic treatment with Tempol (1 mM) in the drinking water restored NO release, augmented vessel relaxation, and increased methacholine-induced Ca2+ responses significantly in aortas from rats on a HS diet but not in aortas from rats on a LS diet. These findings suggest that 1) agonist-induced Ca2+ responses and NO levels are reduced in aortas of rats on a HS diet; 2) increased vascular superoxide levels contribute to NO destruction, and, eventually, to impaired Ca2+ signaling in the vascular endothelial cells; and 3) reduced circulating ANG II levels during elevated dietary salt lead to elevated superoxide levels, impaired endothelial Ca2+ signaling, and reduced NO production in the endothelium.

Salt-induced ANG II suppression impairs the response of cerebral artery smooth muscle cells to prostacyclin.

Recent studies have demonstrated that cerebral arteries from rats fed a high-salt (HS) diet exhibit impaired vasodilation and altered electrophysiological response to reduction in PO2. The present study examined whether an increase in salt intake alters the response of vascular smooth muscle cells (VSMC) to prostacyclin, a crucial mediator of hypoxic dilation in cerebral arteries. VSMC were isolated from cerebral arteries of male Sprague-Dawley rats maintained on an HS (4% NaCl) or a low-salt diet (0.4% NaCl) for 3 days. The stable prostacyclin analog iloprost (10 ng/ml) inhibited serotonin (0.1-10 microM)-induced contractions and the increase in intracellular Ca2+ concentration ([Ca2+]i) in VSMC isolated from arteries of animals fed the low-salt diet. In contrast, iloprost had no effect on serotonin-induced contractions and increases in [Ca2+]i in VSMC isolated from arteries of rats fed the HS diet. Preventing the fall in ANG in rats fed the HS diet by infusion of a low dose of ANG II (5 ng.kg(-1).min(-1) i.v.) restored the inhibitory effect of iloprost on serotonin-induced contractions and increases in [Ca2+]i in VSMC from animals fed the HS diet. These effects were reversed by AT1 receptor blockade with losartan. These results indicate that ANG II suppression secondary to elevated dietary salt intake impairs vascular relaxation and Ca2+ regulation by prostacyclin.

Expression of cytochrome P450-4A isoforms in the rat cremaster muscle microcirculation.

OBJECTIVE: This study sought to identify any specific cytochrome P450 (CYP450) -4A enzyme isoforms expressed in arterioles and/or the surrounding parenchymal tissue of the rat cremaster muscle. METHODS: RT-PCR was used to detect the presence of specific CYP450-4A isoforms in isolated muscle fibers and arterioles from the cremaster muscle of Sprague-Dawley rats; CYP450-4A protein expression was determined by Western blotting. RESULTS: CYP450-4A3 mRNA was expressed in isolated muscle fibers and in cremasteric arterioles, while CYP450-4A8 mRNA was expressed only in cremasteric arterioles. CYP450-4A1 and CYP450-4A2 mRNA were not expressed in arterioles and skeletal muscle cells, although all four isoforms were strongly expressed in the liver. CYP450-4A protein was detected in both the isolated muscle fibers and in the isolated arterioles. CONCLUSIONS: The present study identifies the specific pattern of cytochrome P450-4A isoform expression in arterioles and parenchymal cells of the skeletal muscle microcirculation, and supports the hypothesis that the cytochrome P-450 enzymes may play a role in the regulation of microvascular function in the skeletal muscle microcirculation.