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Heme c is characterized by its covalent attachment to a polypeptide. The attachment is typically to a CXXCH motif in which the two Cys form thioether bonds with the heme, “X” can be any amino acid other than Cys, and the His serves as a heme axial ligand. Some cytochromes c, however, contain heme attachment motifs with three or four intervening residues in a CX3CH or CX4CH motif. Here, the impacts of these variations in the heme attachment motif on heme ruffling and electronic structure are investigated by spectroscopically characterizing CX3CH and CX4CH variants of Hydrogenobacter thermophilus cytochrome c552. In addition, a novel CXCH variant is studied. 1H and 13C NMR, EPR, and resonance Raman spectra of the protein variants are analyzed to deduce the extent of ruffling using previously reported relationships between these spectral data and heme ruffling. In addition, the reduction potentials of these protein variants are measured using protein film voltammetry. The CXCH and CX4CH variants are found to have enhanced heme ruffling and lower reduction potentials. Implications of these results for the use of these noncanonical motifs in nature, and for the engineering of novel heme peptide structures, are discussed. [ABSTRACT FROM AUTHOR]

Here we present the first attempt to test for genetic differentiation among four distinct colour morphs of the Asian golden web spider Nephila antipodiana Walckenaer. Fragments of the 18S rRNA (18S) and cytochrome c oxidase subunit I (COI) genes were sequenced in eight populations of N. antipodiana belonging to four distinct colour morphs: yellow, yellowish green, and two newly discovered morphs, reddish yellow and white-spotted. The nuclear sequences amplified from females of the four colour morphs were identical. The mitochondrial COI sequences, on the other hand, revealed slightly higher variation by recovering three haplotypes belonging to two different clades. Clade I comprises yellow, yellowish green and reddish yellow morphs from the mainland of Southeast Asia and Java, whereas clade II is restricted to white-spotted morph originating from Borneo. The low genetic divergence between both clades, despite being distinctive, undoubtedly provides new insight into the genetic diversity of this polymorphic species. [ABSTRACT FROM AUTHOR]

The steroid superfamily includes a wide range of compounds that are essential for living organisms of the animal and plant kingdoms. Structural modifications of steroids highly affect their biological activity. In this review, we focus on hydroxylation of steroids by bacterial hydroxylases, which take part in steroid catabolic pathways and play an important role in steroid degradation. We compare three distinct classes of metalloenzymes responsible for aerobic or anaerobic hydroxylation of steroids, namely: cytochrome P450, Rieske-type monooxygenase 3-ketosteroid 9α-hydroxylase, and molybdenum-containing steroid C25 dehydrogenases. We analyze the available literature data on reactivity, regioselectivity, and potential application of these enzymes in organic synthesis of hydroxysteroids. Moreover, we describe mechanistic hypotheses proposed for all three classes of enzymes along with experimental and theoretical evidences, which have provided grounds for their formulation. In case of the 3-ketosteroid 9α-hydroxylase, such a mechanistic hypothesis is formulated for the first time in the literature based on studies conducted for other Rieske monooxygenases. Finally, we provide comparative analysis of similarities and differences in the reaction mechanisms utilized by bacterial steroid hydroxylases. [ABSTRACT FROM AUTHOR]

Aryloxypropanolamine plays an important role in several biological activities. It shows multiple actions such as β-blocking, anxiolytic, antihypertensive and inhibition of cytochrome p450. A series of ten aryloxypropanolamine derivatives 6a-6j were synthesized and evaluated for anti-diabetic activity. Two compounds 6b to 6g have shown good anti-diabetic activity. All synthesized compounds (6a-6j) were evaluated for their anti-diabetic activity in STZ induced diabetes model of Wistar rats. [ABSTRACT FROM AUTHOR]

In this study, the main aim was to identify the effects of exposure to 17α-ethinylestradiol-based contraceptives on the ovaries and brain tissues of common carp. For this purpose, histopathological changes were evaluated in ovaries after 21 days of contraceptive exposure. In addition, the expression levels of the CYP1A, CYP3A, FSH, and LH genes were measured in contraceptive-exposed brain tissue and ovaries respectively, using qRT-PCR (p<0.05, p<0.01, and p<0.001, respectively). No histopathological lesions, including inflammation, degeneration, or necrosis in the evaluated ovarian tissue of common carp were found after both high and low levels of exposure to contraceptives. Therefore, it is concluded that these contraceptives were highly dangerous to the reproduction system of common carp; the accumulation of contraceptive waste in the water supply could adversely affect and threat the common carp population. This may indirectly also affect other animals. [ABSTRACT FROM AUTHOR]

Highlights • The effect and mechanism of nano-copper on rat renal function and CYP 450 are proposed. • Nano-copper-induced renal oxidative stress and inflammatory are key factors for inhibiting renal CYP 450. • Nano-copper regulates renal CYP 450 by affecting the expression of relation signaling proteins and nuclear receptors. Abstract Copper nanoparticles (Cu NPs) have widespread application because of their special physicochemical characteristics, however we need to more clearly study the toxicity mechanism of Cu NPs to ensure its safe use in pharmaceutical and animal feed. Thus, the aim of this study was to evaluate the effects and mechanisms of sub-chronic exposure to Cu NPs on renal CYP450 s of rats. In this study, we investigated the effects of Cu NPs on renal oxidative stress, cytokines and histopathology of rats. We found that Cu NPs (200 mg/kg) significantly disordered the function and structure of the kidney and caused a dose-dependent increase in oxidative stress and cytokines, which significantly decreased the levels of mRNA, protein, and activity of CYP450 s. Micro-coppers (Cu MPs) and Cu ions have similar effects, but their effects on CYP450 s were weaker than Cu NPs. The expression of nuclear receptors were inhibited and the expression of Akt, STAT3/5, CREB, p70S6K, NF-κB, P38 and ERK1/2 were activated when the inhibition effects of CYP450 s activity were observed in renal of rats. Therefore, we believe that Cu NPs can activate the STAT, NF-κB and MAPK signaling pathways to down-regulate the expression and activity of CYP450 s by inducing oxidative stress and inflammatory response in rat kidney. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The effect of two second-generation antidepressants escitalopram and venlafaxine on the activity of brain and liver cytochrome P450 2D (CYP2D) involved in the metabolism of psychotropics and neurotransmitters was determined in the chronic mild stress (CMS) model of depression. Escitalopram or venlafaxine (10 mg/kg ip/day each) were administered to control and CMS rats for 5 weeks. The activity of CYP2D was studied by measurement of the rate of bufuralol 1′-hydroxylation in microsomes derived from the liver or different brain structures. The obtained results indicate that CMS and the studied antidepressants had different effects on the CYP2D activity depending on the location of the enzyme. In the brain, CMS produced an increase in the CYP2D activity in the hippocampus. Chronic escitalopram or venlafaxine had no effect on the CYP2D activity in the brain of nonstressed rats, however, the antidepressants increased the enzyme activity in the frontal cortex, hypothalamus and cerebellum of stressed animals. In the liver, CMS did not affect the CYP2D activity, while chronic escitalopram or venlafaxine significantly decreased the CYP2D activity and protein level in nonstressed and stressed rats. We conclude that: 1) CMS stimulates the CYP2D activity in the hippocampus and triggers the stimulatory effect of antidepressants on CYP2D in other brain structures; 2) the local brain metabolism of CYP2D substrates (neurosteroids, neurotransmitters, psychotropics) may be enhanced by CMS and/or antidepressants; 3) in contrast to the brain, the liver metabolism of CYP2D substrates may be slower during long-term treatment with escitalopram or venlafaxine. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Aflatoxin B 1 (AFB 1) is bioactivated by cytochrome P450 (CYP) 3A isoforms in humans to generate the highly reactive epoxide intermediate AFB 1 -8,9-epoxide (AFBO), causing hepatotoxicity and hepatocarcinoma. Due to the unavoidable contamination in their feed, pigs are more likely to be exposed to AFB 1 and indirectly harm human health. Therefore, identifying the porcine CYP3A isoforms involved in AFB 1 -8,9-epoxidation is critical. In this study, we used codon optimization and N-terminal coding sequence modification to modify a CYP3A46 recombinant protein that exhibits good structure and catalytic activities and revealed its strong AFB 1 -8,9-epoxidase activity for the first time. Site-directed mutagenesis, kinetics and docking analyses were performed and demonstrated that residues Phe-108, Ser-119, Phe-215, Phe-304 and Thr-309 play important roles in AFB 1 -8,9-epoxidation and its responsiveness to α-naphthoflavone. Interestingly, we uncovered the dual and reverse roles of Phe-304 in CYP3A46, CYP3A5 and CYP3A4 in AFB 1 oxidation. Unlike the π-π interaction between the Phe-304 phenyl of CYP3A4 and the AFB 1 aromatic ring, Phe-304 of CYP3A46 may function to provide steric hindrance to bind AFB 1. Phe-108 and Phe-215 could stabilize AFB 1 with a potentially productive orientation through van der Waals interactions with AFB 1. Ser-119 and Thr-309 are likely to function to form H-bonds with AFB 1. This study broadens our knowledge of AFB 1 bioactivation in pigs and may contribute to reduce the deleterious effects of AFB 1 in pigs and humans. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract We investigate the mechanism of time-dependent inhibition (TDI) of human cytochrome P450 2D6 (CYP2D6) by 3,4-methylenedioxymethamphetamine (MDMA, ecstasy), one of the most widespread recreational drugs of abuse. In an effort to unravel the kinetic mechanism of the formation of metabolic inhibitory complex (MIC) of CYP2D6 with MDMA-derived carbene we carried out a series of spectrophotometric studies paralleled with registration of the kinetics of time-dependent inhibition (TDI) in CYP2D6-incorporated proteoliposomes. The high amplitude of spectral signal in this system allowed us to characterize the spectral properties of the formed MIC in details and obtain an accurate spectral signature of MIC formation. This information was then used in the studies with CYP2D6-containing microsomes of insect cells (CYP2D6 Supersomes™). Our results demonstrate that in both systems the formation of the ferrous carbene-derived MIC is relatively slow, reversible and is not associated with the accumulation of the ferric carbene intermediate, as takes place in the case of CYP3A4 and podophylotoxin. Furthermore, the limited amplitude of MIC formation suggests that only a fraction (∼50%) of spectrally detectable CYP2D6 in both proteoliposomes and Supersomes participates in the formation of MIC and is therefore involved in the MDMA metabolism. This observation reveals yet another example of a cytochrome P450 that exhibits persistent functional heterogeneity of its population in microsomal membranes. Our study provides a solid methodological background for further mechanistic studies of MIC formation in human liver microsomes and demonstrates that the potency and physiological relevance of MDMA-dependent TDI of CYP2D6 may be overestimated. [ABSTRACT FROM AUTHOR]

Antimycin A-sensitive cyclic electron flow (CEF) was discovered as cyclic phosphorylation by Arnon et al. (1954). Because of its sensitivity to antimycin A, PROTON GRADIENT REGULATION 5 (PGR5)/PGR5-like Photosynthetic Phenotype 1 (PGRL1)-dependent CEF has been considered identical to the CEF of Arnon et al. However, this conclusion still needs additional supportive evidence, mainly because of the absence of definitive methods of evaluating CEF activity. In this study, we revisited the classical method of monitoring cyclic phosphorylation in ruptured chloroplasts to characterize two Arabidopsis mutants: pgr5 , which is defective in antimycin A-sensitive CEF, and chlororespiratory reduction 2-1 ( crr2-1 ), which is defective in chloroplast NDH-dependent CEF. We observed a significant reduction in CEF-dependent pmf formation and consequently ATP synthesis in the pgr5 mutant, although LEF-dependent pmf formation and ATP synthesis were not impaired at photosynthetic photon flux densities below 130 μmol m −2  s −1 . In contrast, the contribution of chloroplast NDH complex to pmf formation and ATP synthesis was not significant. Antimycin A partially inhibited CEF-dependent pmf formation, although there may be further inhibition sites. Unlike in the observation in leaves, the proton conductivity of ATP synthase, monitored as g H + , was not enhanced in ruptured chloroplasts of the pgr5 mutant. [ABSTRACT FROM AUTHOR]

Gene knock-out studies on Geobacter sulfurreducens have shown that the monoheme c -type cytochrome OmcF is essential for the extracellular electron transfer pathways involved in the reduction of iron and uranium oxy-hydroxides, as well as, on electricity production in microbial fuel cells. A detailed electrochemical characterization of OmcF was performed for the first time, allowing attaining kinetics and thermodynamic data. The heterogeneous electron transfer rate constant was determined at pH 7 (0.16 ± 0.01 cm s −1 ) indicating that the protein displays high electron transfer efficiency compared to other monoheme cytochromes. The pH dependence of the redox potential indicates that the protein has an important redox-Bohr effect in the physiological pH range for G . sulfurreducens growth. The analysis of the structures of OmcF allowed us to assign the redox-Bohr centre to the side chain of His 47 residue and its pK a values in the reduced and oxidized states were determined ( pK ox  = 6.73; pK red  = 7.55). The enthalpy, entropy and Gibbs free energy associated with the redox transaction were calculated, pointing the reduced form of the cytochrome as the most favourable. The data obtained indicate that G . sulfurreducens cells evolved to warrant a down-hill electron transfer from the periplasm to the outer-membrane associated cytochrome OmcF. [ABSTRACT FROM AUTHOR]

Abstract: An Escherichia coli whole‐cell biocatalyst for the direct hydroxylation of benzene to phenol has been developed. By adding amino acid derivatives as decoy molecules to the culture medium, wild‐type cytochrome P450BM3 (P450BM3) expressed in E.coli can be activated and non‐native substrates hydroxylated, without supplementing with NADPH. The yield of phenol reached 59 % when N‐heptyl‐ l‐prolyl‐ l‐phenylalanine (C7‐Pro‐Phe) was employed as the decoy molecule. It was shown that decoy molecules, especially those lacking fluorination, reached the cytosol of E. coli, thus imparting in vivo catalytic activity for the oxyfunctionalisation of non‐native substrates to intracellular P450BM3. [ABSTRACT FROM AUTHOR]

The Geobacter metallireducens bacterium can couple the oxidation of a wide range of compounds to the reduction of several extracellular electron acceptors, including pollutants or electrode surfaces for current production in microbial fuel cells. For these reasons, G. metallireducens are of interest for practical biotechnological applications. The use of such electron acceptors relies on a mechanism that permits electrons to be transferred to the cell exterior. The cytochrome PpcA from G. metallireducens is a member of a family composed of five periplasmic triheme cytochromes, which are important to bridge the electron transfer from the cytoplasmic donors to the extracellular acceptors. Using NMR and visible spectroscopic techniques, a detailed thermodynamic characterization of PpcA was obtained, including the determination of the heme reduction potentials and their redox and redox-Bohr interactions. These parameters revealed unique features for PpcA from G. metallireducens compared with other triheme cytochromes from different microorganisms, namely the less negative heme reduction potentials and concomitant functional working potential ranges. It was also shown that the order of oxidation of the hemes is pH-independent, but the protein is designed to couple e-/H+ transfer exclusively at physiological pH. [ABSTRACT FROM AUTHOR]

Ophiopogonin D (OPD) is the chief pharmacological active component of the traditional Chinese herbal prescription drug-Shenmai injection (SMI), which has been used to prevent and treat cardiovascular diseases. In the present study, we investigated whether OPD protectively relieve cardiac hypertrophy against inflammation via inhibiting the expression of NF-κB and examined whether cytochrome P450 2J3 (CYP2J3)was involved in this pathway. H9c2 cells were treated with Angiotensin II (Ang II). Hypertrophy in rat was induced by administration of Ang II infusion. To evaluate the effect of OPD on disease progression and the role of CYP2J3 in this way, inflammatory mediators (NF-κB), specific hypertrophic factors and pathological change were determined in this experiment. Ang II induced hypertrophy with the elevated expression of specific hypertrophy genes and NF-κB signaling molecules. However, these inductive effects were reversed by OPD in conjunction with Ang II. Overexpression of CYP2J3 prevented the excessive expression of NF-κB. In vivo , partial pathological cardiac hypertrophy injuries were relieved after OPD treatment. OPD exerts a positive effect on alleviating cardiac hypertrophy. The mechanism is probably through inhibiting the expression of NF-κB by upregulating CYP2J3 to suppress inflammation. [ABSTRACT FROM AUTHOR]

Neobavaisoflavone (NBIF), a phenolic compound isolated from Psoralea corylifolia L., possesses several significant biological properties. However, the pharmacokinetic behaviors of NBIF have been characterized as rapid oral absorption, high clearance, and poor oral bioavailability. We found that NBIF underwent massive glucuronidation and oxidation by human liver microsomes (HLM) in this study with the intrinsic clearance ( CL int ) values of 12.43, 10.04, 2.01, and 6.99 μL/min/mg for M2, M3, M4, and M5, respectively. Additionally, the CL int values of G1 and G2 by HLM were 271.90 and 651.38 μL/min/mg, respectively, whereas their respective parameters were 59.96 and 949.01 μL/min/mg by human intestine microsomes (HIM). Reaction phenotyping results indicated that CYP1A1, 1A2, 2C8, and 2C19 were the main contributors to M4 (34.96 μL/min/mg), M3 (29.45 μL/min/mg), M3 (13.16 μL/min/mg), and M2 (63.42 μL/min/mg), respectively. UGT1A1, 1A7, 1A8, and 1A9 mainly catalyzed the formation of G1 (250.87 μL/min/mg), G2 (438.15 μL/min/mg), G1 (92.68 μL/min/mg), and G2 (1073.25 μL/min/mg), respectively. Activity correlation analysis assays showed that phenacetin- N -deacetylation was strongly correlated to M3 ( r  = 0.860, p  = 0.003) and M4 ( r  = 0.775, p  = 0.014) in nine individual HLMs, while significant activity correlations were detected between paclitaxel-6-hydroxylation and M2 ( r  = 0.675, p  = 0.046) and M3 ( r  = 0.829, p  = 0.006). There was a strong correlation between β-estradiol-3- O -glucuronide and G1 ( r  = 0.822, p  = 0.007) and G2 ( r  = 0.689, p  = 0.040), as well as between propofol- O -glucuronidation and G1 ( r  = 0.768, p  = 0.016) and G2 ( r  = 0.860, p  = 0.003). Moreover, the phase I metabolism and glucuronidation of NBIF revealed marked species differences, and mice are the best animal model for investigating the metabolism of NBIF in humans. Taken together, characterization of NBIF-related metabolic pathways involving in CYP1A1, 1A2, 2C8, 2C19, and UGT1A1, 1A7, 1A8, 1A9 are helpful for understanding the pharmacokinetic behaviors and conducting in-depth pharmacological studies. [ABSTRACT FROM AUTHOR]

Two types of α- N -heterocyclic piperidylthiosemicarbazone ligands and related Ga(III) complexes were synthesized. The structure of Ga4 and Ga5 were characterized by X-ray single crystal diffraction. We generated the related α- N -heterocycliperidinylthiosemicarbazone analogs to examine the effect of aldehydes or ketones in the Schiff base. The antitumor activity of both type ligands increased after coordination with gallium. Interestingly, the antitumor activity of gallium complexes containing pyridyl groups (first type ligands) is higher than that of pyrazine group-containing (second type ligands) complexes. Gallium complexes significantly depleted cellular iron, resulting in upregulation of transferrin receptor-1 and downregulation of ferritin. They also effectively activate the caspase family proteins (caspase-3/7/9), promote the release of cytochromes from the mitochondria, and ultimately lead to apoptosis. [ABSTRACT FROM AUTHOR]

Abstract: The genus Ochotona (pikas) is a clade of cold‐tolerant lagomorphs that includes many high‐elevation species. Pikas offer a unique opportunity to study adaptations and potential limitations of an ecologically important mammal to high‐elevation hypoxia. We analyzed the evolution of 3 mitochondrial genes encoding the catalytic core of cytochrome c oxidase (COX) in 10 pika species occupying elevations from sea level to 5000 m. COX is an enzyme highly reliant on oxygen and essential for cell function. One amino acid property, the equilibrium constant (ionization of COOH), was found to be under selection in the overall protein complex. We observed a strong relationship between the net value change in this property and the elevation each species occupies, with higher‐elevation species having potentially more efficient proteins. We also found evidence of selection in low‐elevation species for potentially less efficient COX, perhaps trading efficiency for heat production in the absence of hypoxia. Our results suggest that different pika species may have evolved elevation‐specific COX proteins, specialization that may indicate limitations in their ability to shift their elevational ranges in response to future climate change. [ABSTRACT FROM AUTHOR]

Phytophthora capsici is a highly destructive plant pathogen that has spread worldwide. To date, the quinone outside inhibitor (QoI) azoxystrobin has been the choice of farmers for managing this oomycete. In this study, the sensitivity of 90 P. capsici isolates collected from Yunnan, Fujian, Jiangxi, Zhejiang, and Guangdong in southern China to azoxystrobin was assessed based on mycelial growth, sporangia formation, and zoospore discharge. Furthermore, the mitochondrial cytochrome b (cytb) gene from azoxystrobin-sensitive and -resistant P. capsici isolates was compared to investigate the mechanism of QoI resistance. The high values for effective concentration to inhibit 50% of mycelial growth and large variation factor obtained provide strong support for the existence of azoxystrobin-resistant subpopulations in wild populations. The resistance frequency of P. capsici to azoxystrobin was greater than 40%. Sensitive P. capsici isolates were strongly suppressed on V8 medium plates containing azoxystrobin supplemented with salicylhydroxamic acid at 50 µg ml-1, whereas resistant isolates grew well under these conditions. Multiple alignment analysis revealed a missense mutation in the cytb gene that alters codon 137 (GGA to AGA), causing an amino acid substitution of glycine to arginine (G137R). The fitness of the azoxystrobin-sensitive isolate is similar to that of the G137R mutant. Additionally, the P. capsici isolates used in this study exhibited decreased sensitivity to two other QoI fungicides (pyraclostrobin and famoxadone). Necessary measures should be taken to control this trend of resistance to QoI that has developed in P. capsici in southern China. [ABSTRACT FROM AUTHOR]

In mitochondria, copper is a Janus-faced trace element. While it is the essential cofactor of the mitochondrial cytochrome c oxidase, a surplus of copper can be highly detrimental to these organelles. On the one hand, mitochondria are strictly dependent on adequate copper supply for proper respiratory function, and the molecular mechanisms for metalation of the cytochrome c oxidase have been largely characterized. On the other hand, copper overload impairs mitochondria and uncertainties exist concerning the molecular mechanisms for mitochondrial metal uptake, storage and release. The latter issue is of fundamental importance in Wilson disease, a genetic disease characterized by dysfunctional copper excretion from the liver. Prime consequences of the progressive copper accumulation in hepatocytes are increasing mitochondrial biophysical and biochemical deficits. Focusing on this two-sided aspect of mitochondrial copper, we review mitochondrial copper homeostasis but also the impact of excessive mitochondrial copper in Wilson disease. [ABSTRACT FROM AUTHOR]

We aim to investigate the effect of mitochondrial cytochrome c release and its redox state on the mitochondrial-dependent apoptotic pathway and yak meat tenderization during postmortem aging. Results indicated that the internal environment factors considerably decreased, whereas mitochondrial dysfunction increased in the early stage (0–72 h). Moreover, the release of mitochondrial cytochrome c into the cytosol, which was an apoptotic early event and the apoptosome elements in the cytoplasm changed remarkably with the increase of aging time. Meanwhile, N,N,N′,N′-tetramethylphenylene-1, 4-diamine (TMPD) inhibited the mitochondrial apoptotic process and postmortem meat tenderization by influencing the redox state of cytochrome c and apoptotic factors. These findings confirmed that the internal environment factors in the muscles provided essential conditions for mitochondrial cytochrome c, which activated the mitochondrial apoptotic pathway by forming apoptosome complexes. The reduction state of cytochrome c produced by TMPD plays a negative role in the activation of the mitochondrial apoptotic cascade reaction and meat tenderization during postmortem aging. We conclude that mitochondrial cytochrome c release and oxidized cytochrome c plays a significant role in yak meat tenderization by regulating the mitochondrial apoptotic pathway. [ABSTRACT FROM AUTHOR]

We applied a Raman spectroscopy approach to investigate the effect of a cryoprotectant on the redox state of cytochromes on freezing yeast cells. The redox activity of cytochromes was studied using time-resolved photobleaching of the resonance Raman lines. It is found that ice formation causes a drastic change in the redox state of cytochromes in cells frozen without cryoprotectant, whereas in the presence of glycerol the effects of ice formation are more gradual. The photobleaching rate of cells frozen in glycerol solution shows a gradual slowing with temperature decrease and an abrupt slowdown below − 48 °C. This abrupt decrease was interpreted as originating from changes in protein conformational dynamics. Our findings provide important new insights into the transition from active to inactive cytochrome states as cells undergo freezing in the presence and absence of cryoprotectant. [ABSTRACT FROM AUTHOR]

Physaloptera spp. are common nematodes found in the stomach and muscles of mammals, reptiles, amphibians, and birds. Physaloptera spp. have a complicated life cycle with multiple definitive hosts, arthropod intermediate hosts, aberrant infections, and possible second intermediate hosts or paratenic hosts. For example, Physaloptera sp. larvae have been found within the tissues of wild northern bobwhite quail (Colinus virginianus), and it is suspected that quail may serve as paratenic or secondary hosts of these parasites. However, because it is not known what role quail play in the life cycle of Physaloptera spp. and descriptions of Physaloptera spp. larvae are limited, molecular tools may be beneficial when identifying these helminths. In this study, we generated primers using universal nematode primers and obtained a partial mitochondrial cytochrome oxidase 1 (COX 1) sequence. Morphological identification of Physaloptera sp. in bobwhite was confirmed via polymerase chain reaction (PCR), and a phylogenetic tree was constructed using the maximum likelihood method. BLAST analysis revealed a strong identity to other Physaloptera spp. and the phylogenetic tree placed all Physaloptera spp. in the same cluster. We also documented a marked increase in Physaloptera infections in bobwhite from 2017 to 2018, and the similarity of these parasites to Onchocerca volvulus and Wuchereria bancrofti may give insight into the increased prevalence we observed. This study demonstrates the usefulness of molecular techniques to confirm the identity of species that may lack adequate descriptions and provides new insight for the diagnosis and potentially overlooked significance of Physaloptera sp. infections of bobwhite in the Rolling Plains ecoregion of Texas. [ABSTRACT FROM AUTHOR]

A study was conducted to investigate genetic diversity of Echinococcus isolates collected in Hungarian slaughterhouses between 2015 and 2018. Organs of 219 animals with suspected hydatidosis were collected during routine meat inspection and sent to our laboratory. Echinococcus infection was confirmed in 65 animals. These results indicate that prevalence data based on reporting of slaughterhouses are not reliable without the appropriate training of the people responsible for meat inspection. The genetic diversity was evaluated by the DNA sequence analysis of the cytochrome c oxydase subunit 1 (cox1) mitochondrial gene. Echinococcus intermedius (n = 31), Echinococcus granulosus s.s. (n = 2), and Echinococcus multilocularis (n = 3) was identified in swine. In cattle, only E. granulosus s.s. (n = 20) was detected. E. granulosus s.s. (n = 7) was the dominant species in sheep; nevertheless, E. intermedius was also identified in two animals. E. granulosus s.s. (n = 29) and E. intermedius (n = 33) were classified in 13 and three haplotypes, respectively. The genetic diversity and haplotype network of E. granulosus s.s. were similar to that observed in some other countries of Eastern Europe. The genetic diversity of E. intermedius was low with a single dominant haplotype. Cysts were fertile in nine sheep (100%), 22 swine (61%), and three cattle (15%) indicating that all three species play a role in some extent in the epidemiology of cystic echinococcosis in Hungary. Based on the number of animals killed in the slaughterhouses involved in the present study, the rate of infection was 0.013% in sheep, 0.007% in cattle, and 0.001% in swine. As animals with hydatidosis originated from family farms, control programs should mainly focus on these facilities. [ABSTRACT FROM AUTHOR]

Cytochrome (CYP) P450 enzymes have a primary role in antidepressant metabolism and variants in these polymorphic genes are targets for pharmacogenetic investigation. This is the first meta-analysis to investigate how CYP2C19 polymorphisms predict citalopram/escitalopram efficacy and side effects. CYP2C19 metabolic phenotypes comprise poor metabolizers (PM), intermediate and intermediate+ metabolizers (IM; IM+), extensive and extensive+ metabolizers (EM [wild type]; EM+) and ultra-rapid metabolizers (UM) defined by the two most common CYP2C19 functional polymorphisms (rs4244285 and rs12248560) in Caucasians. These polymorphisms were genotyped or imputed from genome-wide data in four samples treated with citalopram or escitalopram (GENDEP, STAR*D, GenPod, PGRN-AMPS). Treatment efficacy was assessed by standardized percentage symptom improvement and by remission. Side effect data were available at weeks 2–4, 6 and 9 in three samples. A fixed-effects meta-analysis was performed using EM as the reference group. Analysis of 2558 patients for efficacy and 2037 patients for side effects showed that PMs had higher symptom improvement (SMD = 0.43, CI = 0.19–0.66) and higher remission rates (OR = 1.55, CI = 1.23–1.96) compared to EMs. At weeks 2–4, PMs showed higher risk of gastro-intestinal (OR = 1.26, CI = 1.08–1.47), neurological (OR = 1.28, CI = 1.07–1.53) and sexual side effects (OR = 1.52, CI = 1.23–1.87; week 6 values were similar). No difference was seen at week 9 or in total side effect burden. PMs did not have higher risk of dropout at week 4 compared to EMs. Antidepressant dose was not different among CYP2C19 groups. CYP2C19 polymorphisms may provide helpful information for guiding citalopram/escitalopram treatment, despite PMs being relatively rare among Caucasians (∼2%). [ABSTRACT FROM AUTHOR]

The extracellular electron transfer (EET) process of Shewanella species is believed to be indispensable for their anaerobic respiration with an electrode. However, the function of outer membrane c -type cytochromes (OM c -Cyts, the primary components of the EET pathway) is still controversial. In this study, we investigated the effect of two OM c -Cyts (MtrC and UndA) of Shewanella putrefaciens CN32 with respect to electricity production and anodic EET efficiency. Deletion of the mtrC gene severely prolonged the microbial fuel cell (MFC) start-up time and decreased electricity production due to depressed flavin-mediated electron transfer, whereas deletion of the undA gene did not have a significant impact. Strikingly, the depression of EET by the deletion of mtrC could be partially relieved by acclimation, which might be due to an increase in the transmembrane transport of electron shuttles and/or the activation of other redox proteins. These results suggested that MtrC may be the primary reductase of flavins to ensure fast indirect EET, which plays a crucial role in MFC electricity generation. [ABSTRACT FROM AUTHOR]

Autoantibodies directed against the P450 side chain cleavage enzyme (P450scc) have been recently described in dogs affected with hypoadrenocorticism, consistent with an immune-mediated pathogenesis of this endocrinopathy. In human autoimmune Addison’s disease, autoantibodies may have a predictive value, being detectable before clinical signs developing, and have been shown to persist for a period of time after diagnosis. Furthermore, an autoantibody positive status post-diagnosis has been associated with successful remission of Addison’s disease following B-cell depletion, suggesting active immunopathology in these cases. The current study was designed to investigate changes in serum P450scc autoantibody status over time in dogs diagnosed with spontaneous hypoadrenocorticism. P450scc autoantibodies were measured using a species-specific radioimmunoprecipitation assay in an initial cohort of 213 dogs, indicating a prevalence of 24%. Thirty two of these dogs had repeat samples (n = 80 in total) available for analysis. Five dogs were consistently P450scc autoantibody positive in all samples, for up to 425 days following first sampling. Three dogs were initially autoantibody positive, then became seronegative at later time points. One dog, a 1 year old female entire standard poodle, was initially negative for P450scc autoantibodies, but seroconverted 18 months after diagnosis. The remaining 23 dogs with multiple samples available were consistently P450scc autoantibody negative. Persistence was not associated with sex (p = .673). This study demonstrates persistence of P450scc autoantibodies in a subset of dogs affected with hypoadrenocorticism and seroconversion over one year post-diagnosis. P450scc autoantibody reactivity in human autoimmune Addison’s disease has been associated with sex, with females having a higher prevalence, possibly due to P450scc expression in the ovary acting as an additional source of antigenic stimulation. However, there was no sex difference in autoantibody persistence in the dogs affected with hypoadrenocorticism. Autontibody persistence in dogs with hypoadrenocorticism might represent persistent pathology, due to residual antigenic stimulation and autoimmune inflammation in the adrenal gland. [ABSTRACT FROM AUTHOR]

Methamphetamine (MA) is an illicit stimulant that affects the central nervous system. Cytochrome P450 2D6 (CYP2D6) plays an important role in MA metabolism. Numerous allelic variants confer substantial variation in CYP2D6 activity among individuals. In the present study, we examined the frequencies of CYP2D6 alleles, including CYP2D6*1, *2, *4, *5, *10, *14A, *14B, *18, and *36, and multiplication, in 82 forensic autopsy cases of MA abusers and 567 autopsy cases in which MA was not detected (controls). Ultrarapid metabolizer (UM), extensive metabolizer (EM), intermediate metabolizer (IM), and poor metabolizer (PM) phenotypes were predicted from CYP2D6 genotypes. Of MA abusers, 64 subjects were predicted to be EM, 17 were IM, and 1 was UM. No MA abuser had the predicted PM phenotype. No significant differences in CYP2D6 phenotype frequencies were found between MA abusers and controls. MA and amphetamine (AMP) concentrations were measured in the right heart blood, left heart blood, peripheral external iliac blood, urine, pericardial fluid, and bone marrow of MA abusers. MA concentrations in urine and bone marrow were significantly higher in IM than in EM. AMP concentration was not associated with CYP2D6 phenotype in any body fluid. These results suggest that the MA concentration in body fluids is influenced by CYP2D6 phenotypes in the Japanese population. [ABSTRACT FROM AUTHOR]

Desomorphine is reported to be the principal pharmacologically active opioid in Krokodil, a homemade injectable drug that is perceived to be a cheaper alternative to heroin. There have been limited studies regarding its pharmacology or detection in biological matrices. The goal of this study was to contribute further knowledge regarding its metabolism. Recombinant human cytochrome P450 enzymes (rCYPs) and recombinant uridine 5'-diphospho-glucuronosyltransferases (rUGTs) were used to investigate the biotransformational pathways involved. Samples were analyzed by liquid chromatography/quadrupole-time of flight-mass spectrometry (LC-Q/TOF-MS). Seven rCYP (rCYP2B6, rCYP2C8, rCYP2C9, rCYP2C18, rCYP2C19, rCYP2D6 and rCYP3A4) enzymes were found to contribute to desomorphine metabolism and eight phase I metabolites were identified, including nordesomorphine, desomorphine-N-oxide, norhydroxydesomorphine, and five hydroxylated species. Inhibition assays were used to confirm individual rCYP isoenzyme activity. Nine rUGTs (rUGT1A1, rUGT1A3, rUGT1A8, rUGT1A9, rUGT1A10, rUGT2B4, rUGT2B7, rUGT2B15, and rUGT2B17) were found to contribute to the formation of desomorphine-glucuronide. [ABSTRACT FROM AUTHOR]

Abstract: Background: Cytochrome P450 2B6 (CYP2B6) is an important drug‐metabolizing enzyme and is expressed in liver. Although human CYP2B6 variants account for variable enzyme properties among individuals and populations, CYP2B6 genetic variants have not been investigated in cynomolgus macaques, widely used in drug metabolism studies. Methods: CYP2B6 was resequenced in 120 cynomolgus macaques and 23 rhesus macaques by direct sequencing. Results: Twenty‐three non‐synonymous variants were found, of which 12 and 3 were unique to cynomolgus macaques and rhesus macaques, respectively. By functional characterization using the 14 variant proteins, 8 variants (V114I, R253C, M435I, V459M, L465P, C475S, R487C, and R487H) showed different rate (>1.5‐fold) of testosterone 16β‐hydroxylation to wild type. However, the four variants (M435I, L465P, C475S, and R487H) were analyzed in liver microsomes, and the catalytic rates were not substantially different from wild type. Conclusions: Macaque CYP2B6 was polymorphic, and the genotype could partly account for variable enzyme activities of macaque CYP2B6. [ABSTRACT FROM AUTHOR]

Covering: 2000 up to 2018 The cytochromes P450 (P450s) are a superfamily of heme-containing monooxygenases that perform diverse catalytic roles in many species, including bacteria. The P450 superfamily is widely known for the hydroxylation of unactivated C–H bonds, but the diversity of reactions that P450s can perform vastly exceeds this undoubtedly impressive chemical transformation. Within bacteria, P450s play important roles in many biosynthetic and biodegradative processes that span a wide range of secondary metabolite pathways and present diverse chemical transformations. In this review, we aim to provide an overview of the range of chemical transformations that P450 enzymes can catalyse within bacterial secondary metabolism, with the intention to provide an important resource to aid in understanding of the potential roles of P450 enzymes within newly identified bacterial biosynthetic pathways. [ABSTRACT FROM AUTHOR]

The bacterium Geobacter sulfurreducens can transfer electrons to quinone moieties of humic substances or to anthraquinone-2,6-disulfonate (AQDS), a model for the humic acids. The reduced form of AQDS (AH 2 QDS) can also be used as energy source by G. sulfurreducens . Such bidirectional utilization of humic substances confers competitive advantages to these bacteria in Fe(III) enriched environments. Previous studies have shown that the triheme cytochrome PpcA from G. sulfurreducens has a bifunctional behavior toward the humic substance analogue. It can reduce AQDS but the protein can also be reduced by AH 2 QDS. Using stopped-flow kinetic measurements we were able to demonstrate that other periplasmic members of the PpcA-family in G. sulfurreducens (PpcB, PpcD and PpcE) also showed the same behavior. The extent of the electron transfer is thermodynamically controlled favoring the reduction of the cytochromes. NMR spectra recorded for 13 C, 15 N-enriched samples in the presence increasing amounts of AQDS showed perturbations in the chemical shift signals of the cytochromes. The chemical shift perturbations on cytochromes backbone NH and 1 H heme methyl signals were used to map their interaction regions with AQDS, showing that each protein forms a low-affinity binding complex through well-defined positive surface regions in the vicinity of heme IV (PpcB, PpcD and PpcE) and I (PpcE). Docking calculations performed using NMR chemical shift perturbations allowed modeling the interactions between AQDS and each cytochrome at a molecular level. Overall, the results obtained provided important structural-functional relationships to rationalize the microbial respiration of humic substances in G. sulfurreducens . [ABSTRACT FROM AUTHOR]

In chloroplasts, the cytochrome (Cyt) b 6 f complex (plastoquinol-plastocyanin-oxidoreductase) provides connectivity between photosystems (PS) II and I, oxidizing plastoquinol (PQH 2 ) formed in PSII and reducing plastocyanin (electron donor to PSI). The overall rate of the intersystem electron transport is determined by PQH 2 oxidation by the Cyt b 6 f complex. In this work, using the DFT method, we have modeled the first step of PQH 2 oxidation by the iron-sulfur protein (ISP) of the Cyt b 6 f complex. The model system contained the iron–sulfur cluster [Fe 2 S 2 ], surrounding amino acid residues, and 2,3,5-trimethylbenzoquinol (TMBQH 2 ), the tailless analog of PQH 2 . The energy profiles of the H atom transfer from TMBQH 2 to the iron-sulfur protein (ISP) were calculated for two modes of the H-transfer, “ diabatic” and “ adiabatic” . The energies of transient states were estimated as 18.4 and 14.4 kcal mol −1 . The energy effects of the reaction were evaluated as 7.7 and −0.2 kcal mol −1 , respectively. The analysis of partial spin densities and electric charges on the atoms of the model system supports the bidirectional mechanism of the H-transfer reaction: an electron is directed to the Fe(1) atom of the [Fe 2 S 2 ] cluster of the ISP, and a proton is accepted by the N ε atom of the His155 residue liganding the Fe(1) atom. Using the results of DFT computations of the energy profiles for the H-transfer reaction, we estimated the rate constants of quinol oxidation within the framework of the Marcus-Dutton-Crofts approach. Our analysis supports the diabatic model of the H-transfer, which implies that the elementary steps of electron and proton transfer occur much more rapidly than the concomitant changes in the system geometry. The rate constants estimated for this mode of H-transfer are in reasonable agreement with experimental data on the intersystem electron transport in chloroplasts. [ABSTRACT FROM AUTHOR]

We have previously described the identification of indolin-2-one-5-carboxamides as potent PAK4 inhibitors. This study expands the structure-activity relationships on our original series by presenting several modifications in the lead compounds, 2 and 3 . A series of novel derivatives was designed, synthesized, and evaluated in biochemical and cellular assay. Most of this series displayed nanomolar biochemical activity and potent antiproliferative activity against A549 and HCT116 cells. The representative compound 10a exhibited excellent enzyme inhibition (PAK4 IC 50  = 25 nM) and cellular potency (A549 IC 50  = 0.58 μM, HCT116 IC 50  = 0.095 μM). An X-ray structure of compound 10a bound to PAK4 was obtained. Crystallographic analysis confirmed predictions from molecular modeling and helped refine SAR results. In addition, Compound 10a displayed focused multi-targeted kinase inhibition, good calculated drug-likeness properties. Further profiling of compound 10a revealed it showed weak inhibitory activity against various isoforms of human cytochrome P450. [ABSTRACT FROM AUTHOR]

The seaside sparrow ( Ammodramus maritimus ) is an abundant and permanent resident of coastal salt marshes impacted by the 2010 BP Deepwater Horizon oil spill. Such terrestrial species are often overlooked in the aftermath of marine spills, despite the potential for long-term oil exposure. We sampled the livers of seaside sparrows residing in oiled and unoiled sites from 2011 to 2014 and quantified expression of cytochrome p450 1A (CYP1A), a gene involved in the metabolism of polycyclic aromatic hydrocarbons (PAHs). In August 2011, CYP1A expression was markedly higher in birds from an oiled site compared to an unoiled site, but differences had disappeared by June 2012. In June 2013, CYP1A expression was elevated compared to 2012 levels on all sites, including those collected from sites that had not been directly oiled during the spill. This rise in CYP1A expression was possibly due to Hurricane Isaac, which made landfall near our sites between the 2012 and 2013 sampling periods. CYP1A expression was significantly attenuated again in June 2014. We also collected sediment samples from the same marshes for a total concentration analysis of PAHs. The PAH concentrations in sediment samples exhibited a similar pattern to the CYP1A data, supporting the link between marsh PAHs and bird CYP1A expression. These results indicate that contamination from marine oil spills can immediately extend to terrestrial ecosystems, and that storms, weather, or other factors may influence subsequent spatial and temporal oil exposure for several additional years. [ABSTRACT FROM AUTHOR]

One of the most prominent glucose dehydrogenases (GDHs) capable of direct electron transfer with electrodes is the FADGDH complex derived from Burkholderia cepacia . This FADGDH complex comprises the following three distinct subunits: the catalytic subunit (α subunit) that has an FAD cofactor in its redox center, a hitch-hiker protein from the bacterial TAT secretion system (γ subunit), and the electron transfer subunit (β subunit). The electron transfer subunit (β subunit) of the FADGDH complex is a three-heme c containing cytochrome c like molecule (heme 1, heme 2 and heme 3 from the N-terminal). In this study, an FADGDH complex harboring a truncated electron transfer subunit composed of only heme 3 was constructed, and its enzymatic activity and electrochemical properties were investigated to elucidate the role of heme 3 and its region. A truncated electron transfer subunit, trβ subunit, was designed using the 3D structures of homologous cytochrome c proteins. The designed trβ subunit was expressed as soluble and functional heme c molecules forming complexes with γα catalytic complexes. Thus, the formed FADGDH complex has inter-molecular electron transfers from the FAD to the trβ subunit, and from the trβ subunit to the external electron acceptor, showing electron transfer subunit-mediated characteristic dye-mediated dehydrogenase activity with a Ru-complex. Therefore, heme 3 in the electron transfer subunit is responsible for accepting the electron from the γα catalytic complex. Moreover, the FADGDH complex harboring the trβ subunit showed DET activity toward the electrode. Spectroelectrochemical observations revealed that the trβ subunit possessed a lower formal potential than any of the 3 hemes in the whole electron transfer subunit. These unexpected electrochemical properties of the heme in the trβ subunit may potentially result in the construction of a DET principle-based glucose sensor, which can be operated at a much lower potential than those achieved using the FADGDH complex with a whole electron transfer subunit. [ABSTRACT FROM AUTHOR]

Background and Objective: A simple approach is proposed to predict drug clearance in children when no paediatric data are available for drugs metabolised by cytochromes.Methods: The maturation functions of cytochrome activity and binding proteins in plasma were combined with several measures of body size to describe drug clearance increase with age. The complete model and different reduced models were evaluated on a large panel of drug clearance data in children. The parameters of the models were estimated by nonlinear regression. Bias and precision of predictions were determined.Results: Two hundred and ten clearance ratios were available for the analysis, corresponding to 53 drugs mainly eliminated by cytochrome metabolism. The age range was 1.5 day to 16 years and there were 30 values for children aged less than 2 years. Fat-free mass at power 0.75 yielded better results than the other body size descriptor tested. The model with the best fit was based on the fat-free mass ratio, the unbound fraction ratio, maturation functions for cytochromes and no maturation function for clearance by other routes. In children aged less than 2 years, the predictive performances were much better with the final model than with the model based on body surface area. The final model was almost unbiased.Conclusions: This model allows the calculation of the maintenance dose of drugs eliminated mainly by cytochromes. After external validation, it could be used in children aged less than 2 years. In older children, the model reduces to a simple approach based on body surface area or preferably on fat-free mass at power 0.75. The model is not suitable for preterm neonates. [ABSTRACT FROM AUTHOR]

Purpose: Early onset preeclampsia (PPE) contributes to life-threatening maternal complications and fetal demise. Pharmacogenomics is a precision medicine, and metabolizing enzymes responsive to antihypertensive remains understudied. The aim of this study was to evaluate the associations of polymorphisms of cytochrome P450, family 2, subfamily D, polypeptide 6 (CYP2D6) and cytochrome P450, family 2, subfamily C, polypeptide 9 (CYP2C9) with PPE and the relationship among CYP2D6, CYP2C9 polymorphisms and response to labetalol therapy.Methods: Totally 105 gravidas diagnosed with PPE (case) and 103 healthy gravidas (control) were recruited between August 2013 and July 2016. Labetalol was given to control blood pressures (BP) with PPE. If labetalol administration alone did not exceed the mean dose and effectively controlled the BP, it would be considered to be valid (n = 75). Genotype and allele frequencies of CYP2C9 gene (rs1057910 and rs4918758) and CYP2D6 gene (rs1065852, rs28371725, rs35742686, and rs3892097) were analyzed by TaqMan PCR. Differences in the genotype and allele frequencies were compared between case-control groups, and the responsive and nonresponsive to labetalol in PPE.Results: Out of six variants, only CC and CT genotypes of the CYP2D6 variants (rs28371725) in PPE were significantly higher than those in the control group [18.1% (19/105) vs 14.6% (15/103); 56.2% (59/105) vs 42.7% (44/103); χ2 = 6.707]. However, there were no differences in maternal age, diastolic pressure, BMI, BW, serum triglyceride, and creatinine were observed among women with CC, CT, or TT genotype of CYP2D6 gene rs28371725 in the experimental group (all P > 0.05). Compared with the gravidas with CT or TT genotype of CYP2D6 gene rs28371725, those with CC genotype had longer gestational age [(32.5 ± 2.1) vs (29.5 ± 1.8) and (29.8 ± 2.2) weeks] and higher plasma albumin [(27.2 ± 9.3) vs (20.3 ± 10.4) and (22.5 ± 7.4) g/L], but lower systolic pressure and 24 h urine protein (LSD test, all P < 0.05). The G allele frequency in CYP2D6 gene rs1065852 nonresponsive to labetalol group was higher than that in responsive labetalol group [93.3% (56/60) vs 76.0% (114/150), χ2 = 8.351, P = 0.004].Conclusions: The polymorphism of CYP2D6 gene rs28371725 may be associated with PPE, and the allele of G in CYP2D6 gene rs1065852 may be associated with the efficacy of labetalol in treatment of PPE. [ABSTRACT FROM AUTHOR]

In this study, complete mitogenomes of P . increta and M . stellatarum (Lepidoptera: Sphingidae) were sequenced and compared with other Sphingidae species. The mitogenomes containing 37 genes and a AT rich region are circular molecules with 15,252 and 15,290 base pairs in length respectively. Except cox1 all 13 protein-coding genes (PCGs) are initiated by ATN codons. Most of PCGs terminate with TAA except nad5 and cox1 in P . increta and nad5 and cox2 in M . stellatarum . Ile and Leu2 are the most frequently used codon families in both species and codons CGC, CCG, TCG and ACG are absent in P . increta while in M . stellatarum CGC, CCG, CTG, AGG are absent. All the tRNA genes could be folded into the typical cloverleaf secondary structure except the trnS1 of P . increta which lost dihydrouridine (DHU) stem. The AT-rich region of both insects includes the motif ATAGA followed by a 18–19 bp polyT stretch and 2–3 short tandem repeats (STRs) of TA, and a poly-A element. Phylogenetic analyses showed that the phylogenetic relationships are ((( Sphinx morio + Manduca sexta ) + ( P . increta + Notonagemia analis scribae )) + ( Agrius convolvuli ) + ( M . stellatarum + ( Ampelophaga rubiginosa + Daphnis nerii )). [ABSTRACT FROM AUTHOR]

Induced hypothermia may protect from ischemia reperfusion injury. The mechanism of protection is not fully understood and may include an effect on mitochondria. Here we describe the effect of hypothermia on circulating mitochondrial (mt) DNA in a substudy of a multicenter randomized trial (the Target Temperature Management trial). Circulating levels of mtDNA were elevated in patients with cardiac arrest at all-time points compared to healthy controls. After 24 h of temperature management, patients kept at 33 °C had significantly lower levels of COX3, NADH1 and NADH2 compared to baseline, in contrast to those kept at 36 °C. After regain of temperature, cytochrome - B was significantly reduced in patients kept at 33 °C with cardiac arrest. Cardiac arrest results in circulating mtDNA levels, which reduced during a temperature management protocol in patients with a target temperature of 33 °C. [ABSTRACT FROM AUTHOR]

Conventional proton pump inhibitors (PPIs) are used as a first-line therapy to treat acid-related diseases worldwide. However, they have a number of limitations including slow onset of action, influence by cytochrome P450 polymorphisms, unsatisfactory effects at night, and instability in acidic conditions. Alternative formulations of conventional PPIs have been developed to overcome these problems; however, these drugs have only introduced small advantages for controlling acid secretion compared to conventional PPIs. Potassium-competitive acid blockers (P-CABs) were developed and have beneficial effects including rapid, long-lasting, and reversible inhibition of the gastric hydrogen potassium ATPase, the proton pump of the stomach. Vonoprazan was recently innovated as a novel, orally active P-CAB. It is currently indicated for the treatment of gastric and duodenal ulcers, reflux esophagitis, and prevention of low-dose aspirin-or nonsteroidal anti-inflammatory drug-related gastric and duodenal ulcer recurrence in Japan. Vonoprazan does not require enteric coating as it is acid-stable, and it can be taken without food because it is quickly absorbed. Vonoprazan accumulates in parietal cells under both acidic and neutral conditions. It does not require an acidic environment for activation, has long-term stability at the site of action, and has satisfactory safety and tolerability. Thus, vonoprazan may address the unmet medical need for the treatment of acid-related diseases. [ABSTRACT FROM AUTHOR]

Cyanogenic glucosides are widespread defence compounds in plants, and they are also found in some arthropods, especially within Lepidoptera. The aliphatic linamarin and lotaustralin are the most common cyanogenic glucosides in Lepidoptera, and they are biosynthesised de novo, and/or sequestered from food plants. Their biosynthetic pathway was elucidated in the burnet moth, Zygaena filipendulae, and consists of three enzymes: two cytochrome P450 enzymes, CYP405A2 and CYP332A3, and a glucosyl transferase, UGT33A1. Heliconius butterflies also produce linamarin and lotaustralin and have close homologs to CYP405A2 and CYP332A3. To unravel the evolution of the pathway in Lepidoptera, we performed phylogenetic analyses on all available CYP405 and CYP332 sequences. CYP332 sequences were present in almost all Lepidoptera, while the distribution of CYP405s among butterflies and moths was much more limited. Negative purifying selection was found in both CYP enzyme families, indicating that the biosynthesis of CNglcs is an old trait, and not a newly evolved pathway. We compared CYP405A2 to its close paralog, CYP405A3, which is not involved in the biosynthetic pathway. The only significant difference between these two enzymes is a smaller substrate binding pocket in CYP405A2, which would make the enzyme more substrate specific. We consider it likely that the biosynthetic pathway of CNglcs in butterflies and moths have evolved from a common pathway, perhaps based on a predisposition for detoxifying aldoximes by way of a CYP332. Later the aldoxime metabolising CYP405s evolved, and a UGT was recruited into the pathway to establish de novo biosynthesis of CNglcs. [ABSTRACT FROM AUTHOR]

Deoxynivalenol (DON) is the most prevalent mycotoxin in cereals worldwide. It can cause adverse health effects in humans and animals, and maximum levels in food and feed have been implemented by food authorities based on risk assessments derived from estimated intake levels. The lack of human toxicokinetic data such as absorption, distribution, and elimination characteristics hinders the direct calculation of DON plasma levels and exposure. In the present study, we have, therefore, used in vitro-to-in vivo extrapolation of depletion constants in hepatic microsomes from different species and allometric scaling of reported in vivo animal parameters to predict the plasma clearance [0.24 L/(h × kg)] and volume of distribution (1.24 L/kg) for DON in humans. In addition, we have performed a toxicokinetic study with oral and intravenous administration of DON in pigs to establish benchmark parameters for the in vitro extrapolation approach. The determined human toxicokinetic parameters were then used to calculate the bioavailability (50-90%), maximum concentration, and total exposure in plasma, and urinary concentrations under consideration of typical DON levels in grain-based food products. The results were compared to data from biomonitoring studies in human populations. [ABSTRACT FROM AUTHOR]

A key feature of the modified Q-cycle of the cytochrome bc 1 and related complexes is a bifurcation of QH 2 oxidation involving electron transfer to two different acceptor chains, each coupled to proton release. We have studied the kinetics of proton release in chromatophore vesicles from Rhodobacter sphaeroides , using the pH-sensitive dye neutral red to follow pH changes inside on activation of the photosynthetic chain, focusing on the bifurcated reaction, in which 4H + are released on complete turnover of the Q-cycle (2H + /ubiquinol (QH 2 ) oxidized). We identified different partial processes of the Q o -site reaction, isolated through use of specific inhibitors, and correlated proton release with electron transfer processes by spectrophotometric measurement of cytochromes or electrochromic response. In the presence of myxothiazol or azoxystrobin, the proton release observed reflected oxidation of the Rieske iron‑sulfur protein. In the absence of Q o -site inhibitors, the pH change measured represented the convolution of this proton release with release of protons on turnover of the Q o -site, involving formation of the ES -complex and oxidation of the semiquinone intermediate. Turnover also regenerated the reduced iron-sulfur protein, available for further oxidation on a second turnover. Proton release was well-matched with the rate limiting step on oxidation of QH 2 on both turnovers. However, a minor lag in proton release found at pH 7 but not at pH 8 might suggest that a process linked to rapid proton release on oxidation of the intermediate semiquinone involves a group with a p K in that range. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bacterial peroxidases belong to the widespread CCP_MauG family. • Bacterial peroxidases are divided into classical and non-classical enzymes. • The active P heme has a OH–/His HS coordination in a HS/LS thermal equilibrium. • Activation and catalytic mechanism are reviewed. • Non-classical YhjA structural model shows the architecture of this tri-hemic enzyme. Bacterial peroxidases are responsible for the reduction of hydrogen peroxide to water. Found in the periplasm of gram-negative bacteria, they are one of the defense mechanisms against endogenous and exogenous peroxide stress under low oxygen tensions. Besides being involved in peroxide detoxification, bacterial peroxidases have been proposed to constitute an alternative pathway to the respiratory chain under anoxic conditions, as demonstrated in E. coli that can use hydrogen peroxide as an electron acceptor in the absence of oxygen. Bacterial peroxidases are c -type cytochromes with either two or three c -type hemes bound to the polypeptide chain, being divided into classical or non-classical, respectively. Orthologous to the classical bacterial peroxidases are the MauG enzymes that share some structural, spectroscopic and sequence similarities but have distinct physiological roles (though for most their function remains unknown). The spectroscopic and kinetic data on bacterial peroxidases are reviewed for both classes. Most classical bacterial peroxidases require reductive activation that consists in structural changes so that the catalytic heme becomes accessible to the substrate. However, non-classical enzymes are ready to bind the hydrogen peroxide as their catalytic center is penta-coordinated, which is also observed in their structural model. The few studies that report the involvement of bacterial peroxidases from pathogenic bacteria in biofilms, is an indication that these enzymes might contribute to their infection mechanism and thus can constitute alternative drug targets. [ABSTRACT FROM AUTHOR]

Cytochrome P450s (CYP) represent a superfamily of b -type hemoproteins catalyzing oxifunctionalization of a vast array of endogenous and exogenous compounds. The present review focuses on assessment of the topology of prospective determinants in substrate entry and product release channels of mammalian P450s, steering the conformational dynamics of substrate accessibility and productive ligand orientation toward the iron-oxene core. Based on a generalized, CYP3A4-related construct, the sum of critical elements from diverse target enzymes was found to cluster within the known substrate recognition sites. The majority of prevalent substrate access/egress tunnels revealed to be of fairly balanced functional importance. The hydrophobicity profile of the candidates revealed to be the most salient feature in functional interaction throughout the conduits, while bulkiness of the residues imposes steric restrictions on substrate traveling. Thus, small amino acids such as prolines and glycines serve as hinges, driving conformational flexibility in ligand passage. Similarly, bottlenecks in the tunnel architecture, being narrowest encounter points within the CYP3A4 model, have a vital function in substrate selectivity along with clusters of aromatic amino acids acting as gatekeepers. In addition, peripheral patches in conduits may house determinants modulating allosteric cooperativity between remote and central domains in the P450 structure. Remarkably, the bulk critical residues lining tunnels in the various isozymes reside in helices B′/C and F/G inclusive of their interhelical turns as well as in helix I. This suggests these regions to represent hotspots for targeted genetic engineering to tailor more sophisticated mammalian P450s exploitable in industrial, biotechnological and medicinal areas. A generalized picture of substrate access channels in mammalian cytochrome P450 enzymes boardered by determinants housed in the six known substrate recognition sites is presented. Key elements ruling substrate entry and passage of the compounds toward the catalytic site were identified. Genetic manipulation of these residues may foster biotechnological exploitation. [Display omitted] • A generalized construct of substrate access/egress channels in mammalian cytochromes P450 was created. • Critical residues boardering the conduits were uncovered. • Functional importance of these elements was analyzed. • Genetic engineering of the key players may open new vistas in biotechnological exploitation of mammalian P450s. [ABSTRACT FROM AUTHOR]

The catalytic cycle of cytochrome c oxidase (COX) couples the reduction of oxygen to the translocation of protons across the inner mitochondrial membrane and involves several intermediate states of the heme a 3 -Cu B binuclear center with distinct absorbance properties. The absorbance maximum close to 605 nm observed during respiration is commonly assigned to the fully reduced species of hemes a or a 3 (R). However, by analyzing the absorbance of isolated enzyme and mitochondria in the Soret (420–450 nm), alpha (560–630 nm) and red (630–700 nm) spectral regions, we demonstrate that the Peroxy (P) and Ferryl (F) intermediates of the binuclear center are observed during respiration, while the R form is only detectable under nearly anoxic conditions in which electrons also accumulate in the higher extinction coefficient low spin a heme. This implies that a large fraction of COX (>50 %) is active, in contrast with assumptions that assign spectral changes only to R and/or reduced heme a. The concentration dependence of the COX chromophores and reduced c -type cytochromes on the transmembrane potential (ΔΨ m) was determined in isolated mitochondria during substrate or apyrase titration to hydrolyze ATP. The cytochrome c -type redox levels indicated that soluble cytochrome c is out of equilibrium with respect to both Complex III and COX. Thermodynamic analyses confirmed that reactions involving the chromophores we assign as the P and F species of COX are ΔΨ m -dependent, out of equilibrium, and therefore much slower than the ΔΨ m -insensitive oxidation of the R intermediate, which is undetectable due to rapid oxygen binding. • Reduction of mitochondrial cytochrome c oxidase hemes not detected during respiration. • Spectral fitting identifies absorbance peaks as species formed after oxygen binding. • Cytochrome c redox state shows electron transfer to oxygen is out of equilibrium. • Membrane potential slows conversion rate of intermediates relative to oxygen binding. [ABSTRACT FROM AUTHOR]

Abstract: We report a unique strategy for the development of a H2O2‐dependent cytochrome P450BM3 system, which catalyzes the monooxygenation of non‐native substrates with the assistance of dual‐functional small molecules (DFSMs), such as N‐(ω‐imidazolyl fatty acyl)‐ l‐amino acids. The acyl amino acid group of DFSM is responsible for bounding to enzyme as an anchoring group, while the imidazolyl group plays the role of general acid–base catalyst in the activation of H2O2. This system affords the best peroxygenase activity for the epoxidation of styrene, sulfoxidation of thioanisole, and hydroxylation of ethylbenzene among those P450–H2O2 system previously reported. This work provides the first example of the activation of the normally H2O2‐inert P450s through the introduction of an exogenous small molecule. This approach improves the potential use of P450s in organic synthesis as it avoids the expensive consumption of the reduced nicotinamide cofactor NAD(P)H and its dependent electron transport system. This introduces a promising approach for exploiting enzyme activity and function based on direct chemical intervention in the catalytic process. [ABSTRACT FROM AUTHOR]

Inhibition of androgen biosynthesis is clinically effective for treating androgen-responsive prostate cancer. Abiraterone is a clinical first-in-class inhibitor of cytochrome P450 17A1 (CYP17A1) required for androgen biosynthesis. However, abiraterone also causes hypertension, hypokalemia, and edema, likely due in part to off-target inhibition of another steroidogenic cytochrome P450, CYP21A2. Abiraterone analogs were designed based on structural evidence that B-ring substituents may favorably interact with polar residues in binding CYP17A1 and sterically clash with residues in the CYP21A2 active site. The best analogs increased selectivity of CYP17A1 inhibition up to 84-fold compared with 6.6-fold for abiraterone. Cocrystallization with CYP17A1 validated the intended new contacts with CYP17A1 active site residues. Docking these analogs into CYP21A2 identified steric clashes that likely underlie decreased binding and CYP21A2 inhibition. Overall, these analogs may offer a clinical advantage in the form of reduced side effects. [ABSTRACT FROM AUTHOR]

Aquatic organisms are usually exposed to a mixture of pesticides instead of individual chemicals. However, risk assessment of pesticides is traditionally based on toxicity data of individual compounds. In this study, we aimed to examine the joint toxicity of two fungicides cyprodinil (CYP) and kresoxim-methyl (KRM) to zebrafish ( Danio rerio ) using a systematic experimental approach. Results from 96-h semi-static test indicated that the LC 50 values of KRM to D. rerio at multiple life stages (embryonic, larval, juvenile and adult stages) ranged from 0.034 (0.015–0.073) to 0.61 (0.39–0.83) mg a.i. L −1 , which were higher than those of CYP ranging from 1.05 (0.88–1.52) to 4.42 (3.24–6.02) mg a.i. L −1 . Pesticide mixtures of CYP and KRM exhibited synergistic effect on embryonic zebrafish. The activities of carboxylesterase (CarE) and cytochrome P450 (Cyp450) were significantly altered in most of the individual and combined exposures compared with the control group. The expressions of seven genes ( Mnsod , cyp17 , crhr 2 , crh , gnrhr 4 , gnrhr 1 and hmgrb ) were significantly altered upon exposure to combined pesticides compared with their individual pesticides. Collectively, these findings suggested joint effects should be considered in the risk assessment of pesticides and development of water quality criteria for the protection of aquatic environment. [ABSTRACT FROM AUTHOR]

Background Tardive dyskinesia (TD) is a severe condition that can affect almost 1 out of 4 patients on current or previous antipsychotic treatment, including both first-generation antipsychotics (FGAs) and second-generation antipsychotics (SGAs). While two novel vesicular monoamine transporter inhibitors, deutetrabenazine and valbenazine, have shown acute efficacy for TD, the majority of patients do not remit, and TD appears to recur once treatment is withdrawn. Hence, prevention of TD remains a crucial goal. Methods We provide a clinically oriented overview of risk factors for TD, dividing them into patient-, illness- and treatment-related variables, as well as nonmodifiable and modifiable factors. Results Unmodifiable patient-related and illness-related risk factors for TD include older age, female sex, white and African descent, longer illness duration, intellectual disability and brain damage, negative symptoms in schizophrenia, mood disorders, cognitive symptoms in mood disorders, and gene polymorphisms involving antipsychotic metabolism and dopamine functioning. Modifiable comorbidity-related and treatment-related factors include diabetes, smoking, and alcohol and substance abuse, FGA vs SGA treatment, higher cumulative and current antipsychotic dose or antipsychotic plasma levels, early parkinsonian side effects, anticholinergic co-treatment, akathisia, and emergent dyskinesia. Discussion Clinicians using dopamine antagonists need to consider risk factors for TD to minimize TD and its consequences. [ABSTRACT FROM AUTHOR]