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Organisms have conversion systems for sulfate ion to take advantage of the chemical features. The use of biologically converted sulfonucleotides varies in an evolutionary manner, with the universal use being that of sulfonate donors. Sulfotransferases have the ability to transfer the sulfonate group of 3′-phosphoadenosine 5′-phosphosulfate to a variety of molecules. Cytosolic sulfotransferases (SULTs) play a role in the metabolism of low-molecular-weight compounds in response to the host organism's living environment. This review will address the diverse functions of the SULT in evolution, including recent findings. In addition to the diversity of vertebrate sulfotransferases, the molecular aspects and recent studies on bacterial and plant sulfotransferases are also addressed. [ABSTRACT FROM AUTHOR]

Polychlorinated biphenyls (PCBs) are persistent organic toxicants derived from legacy pollution sources and their formation as inadvertent byproducts of some current manufacturing processes. Metabolism of PCBs is often a critical component in their toxicity, and relevant metabolic pathways usually include their initial oxidation to form hydroxylated polychlorinated biphenyls (OH-PCBs). Subsequent sulfation of OH-PCBs was originally thought to be primarily a means of detoxication; however, there is strong evidence that it may also contribute to toxicities associated with PCBs and OH-PCBs. These contributions include either the direct interaction of PCB sulfates with receptors or their serving as a localized precursor for OH-PCBs. The formation of PCB sulfates is catalyzed by cytosolic sulfotransferases, and, when transported into the serum, these metabolites may be retained, taken up by other tissues, and subjected to hydrolysis catalyzed by intracellular sulfatase(s) to regenerate OH-PCBs. Dynamic cycling between PCB sulfates and OH-PCBs may lead to further metabolic activation of the resulting OH-PCBs. Ultimate toxic endpoints of such processes may include endocrine disruption, neurotoxicities, and many others that are associated with exposures to PCBs and OH-PCBs. This review highlights the current understanding of the complex roles that PCB sulfates can have in the toxicities of PCBs and OH-PCBs and research on the varied mechanisms that control these roles. [ABSTRACT FROM AUTHOR]

Denne artikkelen undersøker forholdet mellom konflikt og matsikkerhet i Cauca, Colombia. Vi benytter oss av det naturlige eksperimentet som kom i stand som følge av våpenhvilen i 2014 erklært av Colombias revolusjonære væpnede styrker (FARC), den største opprørsgruppen i landet. Våpenhvilen resulterte i en kraftig nedgang i FARC-relatert vold, som ble ytterligere befestet da den colombianske regjeringen og FARC inngikk en fredsavtale i 2016. Vi har gruppert kommunene vi studerer i Cauca i de som var svært utsatt for FARC-relatert vold ved referansetidspunktet (eksponeringsgruppen) og de som var mindre utsatt (kontrollgruppen). Ved å bruke difference-in-differences finner vi at på kort sikt er matsikkerheten større i husholdninger i eksponerte kommuner enn i husholdningene i kontrollkommuner, idet inngåelse av fredsavtalen er assosiert med 51 prosent fall i andelen husholdninger som opplever sult. Effektene varierer innenfor husstanden ved at barn får større forbedringer i sin kostholdskvalitet og matmengde enn voksne. Vi finner også bevis som tyder på at forbedringene i matsikkerhet kan ha vedvart på mellomlang sikt, fem år etter fredsavtalen. Denne casestudien av Cauca fyller et viktig tomrom i litteraturen, da sammenhengenen mellom matsikkerhet og konflikt så langt ikke har blitt studert på lokalt nivå.

Copyright of Internasjonal Politikk is the property of Cappelen Damm Akademisk and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to identify human cytosolic sulfotransferases (SULTs) that are capable of mediating hyperoside sulfation and examine the impact of genetic polymorphisms on their sulfating activity. Of the thirteen known human SULTs analyzed, five (1A1, 1A2, 1A3, 1C2, and 1C4) displayed sulfating activity toward hyperoside. Kinetic parameters of SULT1C4 that showed the strongest sulfating activity were determined. Ten SULT1C4 allozymes previously prepared were shown to display differential sulfating activities toward hyperoside, revealing clearly the functional impact of SULT1C4 genetic polymorphisms. These findings provided a robust biochemical foundation for further studies on the metabolism of hyperoside by sulfation. [ABSTRACT FROM AUTHOR]

The temporary or permanent chemical modification of biomolecules is a crucial aspect in the physiology of all living species. However, while some modules are well characterised also in insects, others did not receive the same attention. This holds true for sulfo-conjugation that is catalysed by cytosolic sulfotransferases (SULT), a central component of the metabolism of endogenous low molecular weight molecules and xenobiotics. In particular, limited information is available about the functional roles of the mosquito predicted enzymes annotated as SULTs in genomic databases. The herein described research is the first example of a biochemical and structural study of a SULT of a mosquito species, in general, and of the malaria vector Anopheles gambiae in particular. We confirmed that the AGAP001425 transcript displays a peculiar expression pattern that is suggestive of a possible involvement in modulating the mosquito reproductive tissues physiology, a fact that could raise attention on the enzyme as a potential target for insect-containment strategies. The crystal structures of the enzyme in alternative ligand-bound states revealed elements distinguishing AgSULT-001425 from other characterized SULTs, including a peculiar conformational plasticity of a discrete region that shields the catalytic cleft and that could play a main role in the dynamics of the reaction and in the substrate selectivity of the enzyme. Along with further in vitro biochemical studies, our structural investigations could provide a framework for the discovery of small-molecule inhibitors to assess the effect of interfering with AgSULT-001425-mediated catalysis at the organismal level.

The regulation of DHEA-sulfate by steroid sulfotransferase (SULT) and steryl-sulfatase (STS) enzymes is a vital process for the downstream formation of many steroid hormones. DHEA-sulfate is the most abundant steroid hormone in the human body; thus, DHEA-sulfate and its hydrolyzed form, DHEA, continue to be evaluated in numerous studies, given their importance to human health. Yet, a basic question of relevance to the reproductive-age female population—whether the two steroid hormones vary across the menstrual cycle—has not been addressed. We applied a validated, multi-step protocol, involving realignment and imputation of study data to early follicular, mid-late follicular, periovulatory, and early, mid-, and late luteal subphases of the menstrual cycle, and analyzed DHEA-sulfate and DHEA serum concentrations using ultraperformance liquid chromatography tandem mass spectrometry. DHEA-sulfate levels started to decrease in the early luteal, significantly dropped in the mid-luteal, and returned to basal levels by the late luteal subphase. DHEA, however, did not vary across the menstrual cycle. The present study deep-mapped trajectories of DHEA and DHEA-sulfate across the entire menstrual cycle, demonstrating a significant decrease in DHEA-sulfate in the mid-luteal subphase. These findings are relevant to the active area of research examining associations between DHEA-sulfate levels and various disease states. [ABSTRACT FROM AUTHOR]

LSZ102 is an orally bioavailable selective oestrogen receptor degrader in clinical development for the treatment of breast cancer. Preclinical studies showed efficacy in xenograft models on oral dosing. However, oral bioavailability was relatively low in several preclinical species (7–33%), and was associated with first-pass metabolism, particularly intestinal first-pass. To investigate metabolism and first-pass effects, metabolites were analysed in human plasma samples after oral dosing of LSZ102 to patients, rat plasma samples after oral dosing of [14C]LSZ102, and in vitro incubations of [14C]LSZ102 with human and rat hepatocytes and intestinal S9 fractions. The kinetics of human sulfotransferase (SULT) enzymes potentially involved in metabolism of LSZ102 was characterised. Sulphate metabolites were found to be the major components in human plasma, as well as in human hepatocytes and intestinal S9 fractions. Contrastingly, glucuronidation was predominant in rat plasma, hepatocytes and intestinal S9. LSZ102 was found to be metabolised by several human SULTs expressed in liver and intestine. The combined metabolism data in rat and human provide supporting evidence for an extensive intestinal first-pass metabolism effect via sulphation in human but glucuronidation in rat. As LSZ102 is metabolised by a number of different SULTs, drug-drug interactions resulting from the inhibition of one SULT are unlikely. Despite the observed species difference in metabolism, the major human metabolites of LSZ102, sulphate M5, glucuronide M4, and secondary glucuronide/sulphate metabolite M12, have no or weak pharmacological activity and are not considered a toxicity risk as they are phase II conjugative metabolites. [ABSTRACT FROM AUTHOR]

For in vitro investigations on human sulfotransferase (SULT) catalyzed phase II metabolism, the costly cofactor 3′-phosphoadenosine-5′-phosphosulfate (PAPS) is generally needed. In the present study, we developed and optimized a new approach that combines SULT-dependent biotransformation using recombinant and permeabilized fission yeast cells (enzyme bags) with PAPS production in situ applying quality by design principles. In the initial application of the procedure, yeast cells expressing human SULT1A3 were used for the production of 4′-hydroxypropranolol-4-O-sulfate from 4-hydroxypropranolol. The optimized protocol was then successfully transferred to other sulfonation reactions catalyzed by SULT2A1, SULT1E1, or SULT1B1. The concomitant degradation of some sulfoconjugates was investigated, and further optimization of the reaction conditions was performed in order to reduce product loss. Also, the production of stable isotope labelled sulfoconjugates was demonstrated utilizing isotopically labelled substrates or 34S-sulfate. Overall, this new approach results in higher space-time yields while at the same time reducing experimental cost.

Doxorubicin is a chemotherapeutic drug widely utilized in cancer treatment. An enzyme critical to doxorubicin metabolism is the cytosolic sulfotransferase (SULT) SULT1C4. This study investigated the functional impact of SULT1C4 single nucleotide polymorphisms (SNPs) on the sulfation of doxorubicin by SULT1C4 allozymes. A comprehensive database search was performed to identify various SULT1C4 SNPs. Ten nonsynonymous SULT1C4 SNPs were selected, and the corresponding cDNAs, packaged in pGEX-2TK expression vector, were generated via site-directed mutagenesis. Respective SULT1C4 allozymes were bacterially expressed and purified by affinity chromatography. Purified SULT1C4 allozymes, in comparison with the wild-type enzyme, were analysed for sulphating activities towards doxorubicin and 4-nitrophenol, a prototype substrate. Results obtained showed clearly differential doxorubicin-sulphating activity of SULT1C4 allozymes, implying differential metabolism of doxorubicin through sulfation in individuals with distinct SULT1C4 genotypes. [ABSTRACT FROM AUTHOR]

The regulation of DHEA-sulfate by steroid sulfotransferase (SULT) and steryl-sulfatase (STS) enzymes is a vital process for the downstream formation of many steroid hormones. DHEA-sulfate is the most abundant steroid hormone in the human body; thus, DHEA-sulfate and its hydrolyzed form, DHEA, continue to be evaluated in numerous studies, given their importance to human health. Yet, a basic question of relevance to the reproductive-age female population—whether the two steroid hormones vary across the menstrual cycle—has not been addressed. We applied a validated, multi-step protocol, involving realignment and imputation of study data to early follicular, mid-late follicular, periovulatory, and early, mid-, and late luteal subphases of the menstrual cycle, and analyzed DHEA-sulfate and DHEA serum concentrations using ultraperformance liquid chromatography tandem mass spectrometry. DHEA-sulfate levels started to decrease in the early luteal, significantly dropped in the mid-luteal, and returned to basal levels by the late luteal subphase. DHEA, however, did not vary across the menstrual cycle. The present study deep-mapped trajectories of DHEA and DHEA-sulfate across the entire menstrual cycle, demonstrating a significant decrease in DHEA-sulfate in the mid-luteal subphase. These findings are relevant to the active area of research examining associations between DHEA-sulfate levels and various disease states.

The phylogenetic diversity of Ochrophyta, a diverse and ecologically important radiation of algae, is still incompletely understood even at the level of the principal lineages. One taxon that has eluded simple classification is the marine flagellate genus Olisthodiscus. We investigated Olisthodiscus luteus K‐0444 and documented its morphological and genetic differences from the NIES‐15 strain, which we described as Olisthodiscus tomasii sp. nov. Phylogenetic analyses of combined 18S and 28S rRNA sequences confirmed that Olisthodiscus constitutes a separate, deep, ochrophyte lineage, but its position could not be resolved. To overcome this problem, we sequenced the plastid genome of O. luteus K‐0444 and used the new data in multigene phylogenetic analyses, which suggested that Olisthodiscus is a sister lineage of the class Pinguiophyceae within a broader clade additionally including Chrysophyceae, Synchromophyceae, and Eustigmatophyceae. Surprisingly, the Olisthodiscus plastid genome contained three genes, ycf80, cysT, and cysW, inherited from the rhodophyte ancestor of the ochrophyte plastid yet lost from all other ochrophyte groups studied so far. Combined with nuclear genes for CysA and Sbp proteins, Olisthodiscus is the only known ochrophyte possessing a plastidial sulfate transporter SulT. In addition, the finding of a cemA gene in the Olisthodiscus plastid genome and an updated phylogenetic analysis ruled out the previously proposed hypothesis invoking horizontal cemA transfer from a green algal plastid into Synurales. Altogether, Olisthodiscus clearly represents a novel phylogenetically distinct ochrophyte lineage, which we have proposed as a new class, Olisthodiscophyceae. [ABSTRACT FROM AUTHOR]

Målet med denne artikkelen er å vise hvordan tekstene til Knut Hamsun reiser over lande- og sjangergrenser, nærmere sagt: hvordan hans episke tekster fungerer på de polske scenene. Artikkelen begynner med en historisk oversikt over Hamsuns verk i polsk oversettelse fra 1890-årene til dagens dato. Deretter blir en liste over alle polske dramatiseringer av romanene hans presentert og omtalt. To av forestillingene, nemlig Tangen (2005, regissert av Łukasz Witt-Michałowski) og Knut Hamsuns sult (Głód Knuta Hamsuna, 2010, gjennomført av Łukasz Witt-Michałowski og Ryszard Kalinowski) blir nærmere analysert med hensyn til tekniske løsninger anvendt i framføringene og eventuelle teaterteorier eller -tilnærminger disse løsningene har sitt opphav i. Artikkelen omtaler også mottakelse av de to forestillingene av polske teaterkritikere og anmeldere.

Artikkelen tar for seg fire sceniske adaptasjoner av Knut Hamsuns Sult. Den teoretiske diskusjonen reflekterer over dramatiseringens vansker og den innfløkte fortellerteknikken i Hamsuns jeg-roman. Med utgangspunkt i moderne adaptasjonsteori som ikke lenger insisterer på foreleggets primat, blir fire ulike sceniske versjoner analysert ut fra hvordan fortellerstemmen, bymiljøet, persongalleriet og kunstnertilværelsen er oversatt fra romanens medium til dramatikk. I artikkelen kommenterer jeg de utvalgte Sult-bearbeidelsene både i sammenligning med det litterære forelegget og på adaptasjonenes egne premisser. Analysen viser at de fleste adaptasjonene har som mål å gestalte Sult-heltens indre monolog på scenen. Skrivesperren og Sult-heltens vandring i storbyen, som er så sentrale motiver i romanen, blir derimot ikke alltid vektlagt. Det overordnede formålet med artikkelen er å høyne den akademiske oppmerksomheten om de tallrike dramatiseringene av Hamsuns romaner.

Copyright of Nordlit is the property of Universitetet i Tromsoe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nordlit is the property of Universitetet i Tromsoe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Previous studies have revealed sulfation as a major pathway for the metabolism of hesperetin, naringenin and apigenin. The current study was designed to identify the human cytosolic sulfotransferase (SULT) enzyme(s) capable of sulfating these flavonoid compounds. Of the thirteen human SULTs, six (1A1, 1A2, 1A3, 1B2, 1C4, 1E1) displayed significant sulfating activity toward hesperetin, five (1A1, 1A2, 1A3, 1B2, 1C4) displayed sulfating activity towards naringenin, and four (1A1, 1A2, 1A3, 1C4) showed sulfating activity towards apigenin. Of the four human organ specimens tested, liver and intestine cytosols displayed much higher hesperetin-, naringenin- and apigenin-sulfating activity than lung and kidney cytosols. Moreover, sulfation of hesperetin, naringenin and apigenin was shown to take place in HepG2 human hepatoma cells and Caco-2 human colon adenocarcinoma cells under cultured conditions. Taken together, these results provided a biochemical basis underlying the metabolism of hesperetin, naringenin and apigenin through sulfation in humans. [ABSTRACT FROM AUTHOR]

Cytosolic sulfotransferases (SULTs), drug-metabolizing enzymes essential for the metabolism of endogenous biochemicals and foreign compounds, have been characterized in humans, but remain to be investigated in cynomolgus macaques, important species in drug metabolism studies. In this study, based on the genome data, cynomolgus SULT1A1, SULT1A3, SULT1B1, SULT1C2v1, SULT1C2v2, SULT1C4, SULT1E1, and SULT2A1 cDNAs were isolated and characterized. Among these, cynomolgus SULT1C2v2 was highly homologous to human SULT1C2P1 (pseudogene). These cynomolgus SULT cDNAs had high sequence identities (95–97%) to, and closely clustered with their human orthologs in a phylogenetic tree. Gene structure and genomic organization of each cynomolgus SULT were similar to those of the human ortholog. Among the 10 tissue types analyzed, cynomolgus SULTs showed distinct expression patterns similar to human SULTs; more specifically, mRNA was most abundantly expressed in livers (SULT1A1, SULT1C2v2, SULT1C4, and SULT2A1), jejunum (SULT1A3, SULT1B1, and SULT1E1), or kidneys (SULT1C2v1). The most abundant SULT mRNA was SULT2A1, SULT1E1, and SULT1C4 found in livers, jejunum, and kidneys, respectively. Recombinant cynomolgus SULT1A1, SULT1A3, SULT1B1, SULT1C2v1, SULT1C2v2, SULT1C4, SULT1E1, and SULT2A1 in bacterial cytosolic fractions mediated 3′-phosphoadenosine-5′-phosphosulfate-dependent sulfate conjugations of typical human SULT substrates, 1-naphthol, p -nitrophenol, dopamine, dehydroepiandrosterone, and estradiol. Taken together, these results suggest molecular and functional similarities of SULTs between cynomolgus macaques and humans. [ABSTRACT FROM AUTHOR]

Previous studies demonstrated that sulfate conjugation is involved in the metabolism of three commonly used breast cancer drugs, tamoxifen, raloxifene and fulvestrant. The current study was designed to systematically identify the human cytosolic sulfotransferases (SULTs) that are capable of sulfating raloxifene, fulvestrant, and two active metabolites of tamoxifen, afimoxifene and endoxifen. A systematic analysis using 13 known human SULTs revealed SULT1A1 and SULT1C4 as the major SULTs responsible for the sulfation of afimoxifene, endoxifen, raloxifene and fulvestrant. Kinetic parameters of these two human SULTs in catalyzing the sulfation of these drug compounds were determined. Sulfation of afimoxifene, endoxifen, raloxifene and fulvestrant under metabolic conditions was examined using HepG2 human hepatoma cells and MCF-7 breast cancer cells. Moreover, human intestine, kidney, liver, and lung cytosols were examined to verify the presence of afimoxifene/endoxifen/raloxifene/fulvestrant-sulfating activity.

Sulphated cholesterol, like its unsulphated counterpart, is known to be biologically active and serves a myriad of biochemical/physiological functions. Of the 13 human cytosolic sulphotransferases (SULTs), SULT2B1b has been reported as the main enzyme responsible for the sulphation of cholesterol. As such, SULT2B1b may play the role as a key regulator of cholesterol metabolism. Variations in the sulphating activity of SULT2B1b may affect the sulphation of cholesterol and, consequently, the related physiological events. This study was designed to evaluate the impact of the genetic polymorphisms on the sulphation of cholesterol by SULT2B1b. Ten recombinant SULT2B1b allozymes were generated, expressed, and purified. Purified SULT2B1b allozymes were shown to display differential cholesterol-sulphating activities, compared with the wild-type enzyme. Kinetic studies revealed further their distinct substrate affinity and catalytic efficiency toward cholesterol. These findings showed clearly the impact of genetic polymorphisms on the cholesterol-sulphating activity of SULT2B1b allozymes, which may underscore the differential metabolism of cholesterol in individuals with different SULT2B1b genotypes. [ABSTRACT FROM AUTHOR]

Members of the cytosolic sulfotransferase (SULT) SULT2A subfamily are known to be critically involved in the homeostasis of steroids and bile acids. SULT2A8, a 7α-hydroxyl bile acid-preferring mouse SULT, has been identified as the major enzyme responsible for the mouse-specific 7-O-sulfation of bile acids. Interestingly, SULT2A8 lacks a conservative catalytic His residue at position 99th. The catalytic mechanism underlying the SULT2A8-mediated 7-O-sulfation of bile acids thus remained unclear. In this study, we performed a mutational analysis in order to gain insight into this yet-unresolved issue. Results obtained revealed two amino acid residues, His48 and Leu99, that are unique to the mouse SULT2A8, but not other SULTs, are essential for its 7-O-sulfating activity toward bile acids. These findings suggested that substitutions of two amino acids, which might have occurred during the evolution of the mouse SULT2A8 gene, endowed mouse SULT2A8 the capacity to catalyze the 7-O-sulfation of bile acids. [ABSTRACT FROM AUTHOR]

The cytosolic sulphotransferase SULT1C3 remained the most poorly understood human SULT. The SULT1C3 gene has been shown to contain alternative exons 7 and 8, raising the question concerning their evolutionary origin and implying the generation of multiple SULT1C3 variants. Two SULT1C3 splice variants, SULT1C3a and SULT1C3d, were investigated to verify the impact of alternative C-terminal sequences on their sulphating activity. Sequence homology and gene location analyses were performed to verify the orthology of the SULT1C3 gene. The SULT1C3 gene appears to be present only in humans and other primates, but alternative exons 7b and 8b share high degrees of homology with corresponding regions of rodent SULT1C1 genes, implying their evolutionary origin being from a defunct human SULT1C1 gene. Purified recombinant SULT1C3a and SULT1C3d were analyzed for sulphating activities toward a variety of endogenous and xenobiotic compounds. While SULT1C3a displayed weaker activities and strict substrate specificity toward hydroxyl-chlorinated biphenyls, SULT1C3d exhibited broader substrate specificity toward bile acids and thyroid hormones as well as hydroxyl-chlorinated biphenyls. Molecular docking simulation suggested that Tyr249 and Met257 may play an important role in substrate recognition by SULT1C3d. Alternative splicing of exons 7 and 8 sequences resulted in differential catalytic properties of SULT1C3 variants. [ABSTRACT FROM AUTHOR]

Sea lamprey (Petromyzon marinus) control in the Laurentian Great Lakes of North America often relies on the application of 3-trifluoromethyl-4-nitrophenol (TFM) and niclosamide mixtures to kill larval sea lamprey. Selectivity of TFM against lampreys appears to be due to differential detoxification ability in these jawless fishes compared to bony fishes, particularly teleosts. However, the proximate mechanisms of tolerance to the TFM and niclosamide mixture and the mechanisms of niclosamide toxicity on its own are poorly understood, especially among non-target fishes. Here, we used RNA sequencing to identify specific mRNA transcripts and functional processes that responded to niclosamide or a TFM:niclosamide mixture in bluegill (Lepomis macrochirus). Bluegill were exposed to niclosamide or TFM:niclosamide mixture, along with a time-matched control group, and gill and liver tissues were sampled at 6, 12, and 24 h. We summarized the whole-transcriptome patterns through gene ontology (GO) term enrichment and through differential expression of detoxification genes. The niclosamide treatment resulted in an upregulation of several transcripts associated with detoxification (cyp , ugt , sult , gst), which may help explain the relatively high detoxification capacity in bluegill. Conversely, the TFM:niclosamide mixture resulted in an enrichment of processes related to arrested cell cycle and growth, and cell death alongside a diverse detoxification gene response. Detoxification of both lampricides likely involves the use of phase I and II biotransformation genes. Our findings strongly suggest that the unusually high tolerance of bluegill to lampricides is due to these animals having an inherently high capacity and flexible detoxification response to such compounds. [Display omitted] • · Sea lamprey control uses TFM (3-trifluoromethyl-4-nitrophenol) & niclosamide as lampricides. • Bluegill were exposed to a TFM:niclosamide mixture or niclosamide for up to 24h; Gill & liver were sampled. • Tissues underwent RNA-seq with transcriptome analyses for differential expression & gene ontogeny (GO) term enrichment. • Niclosamide had minimal impact; Mixture had high detoxification response & enrichment of GO terms with cell death/growth. • Bluegill have a high inherent capacity to detoxify lampricides leading to high lampricide tolerances. [ABSTRACT FROM AUTHOR]

5α-Cyprinol 27-sulfate is the major biliary bile salt present in cypriniform fish including the zebrafish (Danio rerio). The current study was designed to identify the zebrafish cytosolic sulfotransferase (Sult) enzyme(s) capable of sulfating 5α-cyprinol and to characterize the zebrafish 5α-cyprinol-sulfating Sults in comparison with human SULT2A1. Enzymatic assays using zebrafish homogenates showed 5α-cyprinol-sulfating activity. A systematic analysis, using a panel of recombinant zebrafish Sults, revealed two Sult2 subfamily members, Sult2st2 and Sult2st3, as major 5α-cyprinol-sulfating Sults. Both enzymes showed higher activities using 5α-cyprinol as the substrate, compared to their activity with DHEA, a representative substrate for mammalian SULT2 family members, particularly SULT2A1. pH-Dependence and kinetics experiments indicated that the catalytic properties of zebrafish Sult2 family members in mediating the sulfation of 5α-cyprinol were different from those of either zebrafish Sult3st4 or human SULT2A1. Collectively, these results imply that both Sult2st2 and Sult2st3 have evolved to sulfate specifically C 27 -bile alcohol, 5α-cyprinol, in Cypriniform fish, whereas the enzymatic characteristics of zebrafish Sult3 members, particularly Sult3st4, correlated with those of human SULT2A1. [ABSTRACT FROM AUTHOR]

The interindividual variability in drug response is a major issue in clinical practice and in drug development. Sulfoconjugation is an important Phase II reaction catalyzed by cytosolic sulfotransferases (SULTs), playing a major role in homeostatic functions, xenobiotic detoxification, and carcinogen bioactivation. SULT display wide interindividual variability, explained only partially by genetic variation, suggesting that other non-genetic, epigenetic, and environmental influences could be major determinants of variability in SULT activity. This review focuses on the factors known to influence SULT variability in expression and activity and the available evidence regarding the impact of SULT variability on drug response. [ABSTRACT FROM AUTHOR]

In this study, we aimed to obtain a comprehensive account of the human cytosolic sulfotransferases (SULTs) that are capable of sulfating 6- O-desmethylnaproxen ( O-DMN), a major metabolite of naproxen. Of the 13 known human SULTs tested, 7 (SULT1A1, SULT1A2, SULT1A3, SULT1B1, SULT1C2, SULT1C4, and SULT1E1) displayed O-DMN-sulfating activity, when analyzed using an elevated substrate concentration (500 μmol·L−1) together with 14 μmol·L−1 of the sulfate donor, 3′-phosphoadenosine-5′-phosphosulfate (PAPS). At 10 μmol·L−1 O-DMN concentration, however, only SULT1A1 and SULT1A3 displayed detectable activity, with the former being nearly 2 orders of magnitude more active than the latter. A pH-dependence study indicated that SULT1A1 exhibited a broad pH optimum spanning pH 5.5-7. Kinetic parameters of the sulfation of O-DMN by SULT1A1 were determined. The production and release of sulfated O-DMN was demonstrated using cultured human HepG2 hepatoma cells and Caco-2 colon carcinoma cells. Moreover, assays using human organ specimens revealed that the O-DMN-sulfating activities present in the cytosols of liver and small intestine (at 502.5 and 497.2 pmol·min−1·(mg protein)−1, respectively) were much higher than those detected for the cytosols of lung and kidney. Taken together, these results provided relevant information concerning the sulfation of O-DMN both in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Pterygoplichthys is a genus of related suckermouth armoured catfishes native to South America, which have invaded tropical and subtropical regions worldwide. Physiological features, including an augmented resistance to organic xenobiotics, may have aided their settlement in foreign habitats. The liver transcriptome of Pterygoplichthys anisitsi was sequenced and used to characterize the diversity of mRNAs potentially involved in the responses to natural and anthropogenic chemicals. In total, 66,642 transcripts were assembled. Among the identified defensome genes, cytochromes P450 (CYP) were the most abundant, followed by sulfotransferases (SULT), nuclear receptors (NR) and ATP binding cassette transporters (ABC). A novel expansion in the CYP2Y subfamily was identified, as well as an independent expansion of the CYP2AAs. Two expansions were also observed among SULT1. Thirty-two transcripts were classified into twelve subfamilies of NR, while 21 encoded ABC transporters. The diversity of defensome transcripts sequenced herein could contribute to this species' resistance to organic xenobiotics. [ABSTRACT FROM AUTHOR]

Curcumin (CUR) is known to exert numerous health-promoting effects in pharmacological studies, but its low bioavailability hinders the development of curcumin as a feasible therapeutic agent. Piperine (PIP) has been reported to enhance the bioavailability of curcumin, but the underlying mechanism remains poorly understood. In an attempt to find the mechanism by which piperine enhances the bioavailability of curcumin, the dosage ratio (CUR: PIP) and pre-treatment with piperine were hypothesized as key factors for improving the bioavailability in this combination. Therefore, combining curcumin with piperine at various dose ratios (1:1 to 100:1) and pre-dosing with piperine (0.5-8 h prior to curcumin) were designed to investigate their contributions to the pharmacokinetic parameters of curcumin in rats and their effects on the expression of UGT and SULT isoforms. It was shown that the Cmax and AUC0-t of curcumin were slightly increased by 1.29 and 1.67 fold at a ratio of 20:1, while curcumin exposure was enhanced significantly in all the piperine pre-treated rats (0.5-8 h), peaking at 6 h (a 6.09-fold and 5.97-fold increase in Cmax and AUC0-t, p < 0.01), regardless of the unchanged t1/2 and Tmax. Also observed was a time-dependent inhibition of the hepatic expression of UGT1A6, 1A8, SULT1A1, 1A3, and the colonic expression of UGT1A6 that occurred within 6 h of piperine pre-treatment but was reversed at 8 h, which correlated with the changes in curcumin exposure. Similarly, the inhibitory effect of piperine on most of the UGTs and SULTs are time-dependent in Caco-2 and HepG2 cells. It is concluded that piperine pre-treatment time-dependently improves the bioavailability of curcumin through the reversible and selective inhibition of UGTs and SULTs. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The aim of the present study was to identify human cytosolic sulfotransferases (SULTs) that are capable of sulfating benzyl alcohol and to examine whether benzyl alcohol sulfation may occur in cultured human cells as well as in human organ homogenates. A systematic analysis revealed that of the 13 known human SULTs, SULT1A1 SULT1A2, SULTA3, and SULT1B1 are capable of mediating the sulfation of benzyl alcohol. The kinetic parameters of SULT1A1 that showed the strongest benzyl alcohol-sulfating activity were determined. HepG2 human hepatoma cells were used to demonstrate the generation and release of sulfated benzyl alcohol under the metabolic settings. Moreover, the cytosol or S9 fractions of human liver, lung, kidney and small intestine were examined to verify the presence of benzyl alcohol sulfating activity in vivo. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Kaempferol is a well-known flavonoid; however, it lacks extensive pharmacokinetic studies. Phase II metabolic enzymes and efflux transporters play an important role in the disposition of flavonoids. This study aimed to investigate the mechanism by which phase II metabolic enzymes and efflux transporters determine the in vivo exposure of kaempferol. Pharmacokinetic analysis in Sprague-Dawley rats revealed that kaempferol was mostly biotransformed to conjugates, namely, kaempferol-3-glucuronide (K-3-G), kaempferol-7-glucuronide (K-7-G), and kaempferol-7-sulfate, in plasma. K-3-G represented the major metabolite. Compared with that in wild-type mice, pharmacokinetics in knockout FVB mice demonstrated that the absence of multidrug resistance protein 2 (MRP2) and breast cancer resistance protein (BCRP) significantly increased the area under the curve (AUC) of the conjugates. The lack of MRP1 resulted in a much lower AUC of the conjugates. Intestinal perfusion in rats revealed that the glucuronide conjugates were mainly excreted in the small intestine, but 7-sulfate was mainly excreted in the colon. In Caco-2 monolayers, K-7-G efflux toward the apical (AP) side was significantly higher than K-3-G efflux. In contrast, K-3-G efflux toward the basolateral (BL) side was significantly higher than K-7-G efflux. The BL-to-AP efflux was significantly reduced in the presence of the MRP2 inhibitor LTC4. The AP-to-BL efflux was significantly decreased in the presence of the BL-side MRPs inhibitor MK571. The BCRP inhibitor Ko143 decreased the glucuronide conjugate efflux. Therefore, kaempferol is mainly exposed as K-3-G in vivo, which is driven by phase II metabolic enzymes and efflux transporters (i.e., BCRP and MRPs). [ABSTRACT FROM AUTHOR]

1. This study aimed to investigate the involvement of sulfation in the metabolism of 6-hydroxymelatonin (6-OH-Mel), N-acetylserotonin (NAS) and 4-hydroxyramelteon (4-OH-Ram), and to identify and characterize the human cytosolic sulfotransferases (SULTs) capable of sulfating these drug compounds. 2. A systematic analysis using 13 known human SULTs revealed that SULT1A1 displayed the strongest activity in catalyzing the sulfation of 6-OH-Mel and 4-OH-Ram, whereas SULT1C4 exhibited the strongest sulfating-activity towards NAS. pH-dependence and kinetic parameters of these SULT enzymes in mediating the sulfation of respective drug compounds were determined. A metabolic labeling study showed the generation and release of [35S]sulfated 6-OH-Mel, NAS and 4-OH-Ram by HepG2 human hepatoma cells and Caco-2 human colon adenocarcinoma cells labeled with [35S]sulfate in the presence of these drug compounds. Cytosols of human lung, liver, kidney and small intestine were examined to verify the presence of 6-OH-Mel-, NAS- and 4-OH-Ram-sulfating activityin vivo. Of the four human organ samples tested, small intestine and liver cytosols displayed considerably higher 6-OH-Mel-, NAS- and 4-OH-Ram-sulfating activities than those of lung and kidney. 3. Collectively, these results provided a molecular basis for the metabolism of 6-OH-Mel, NAS and 4-OH-Ram through sulfation. [ABSTRACT FROM PUBLISHER]

Sulfation has been reported to be a major pathway for the metabolism and inactivation of rotigotine in vivo. The current study aimed to identify the human cytosolic sulfotransferase (SULT) enzyme(s) capable of mediating the sulfation of rotigotine. Of the 13 known human SULTs examined, 6 of them (SULT1A1, 1A2, 1A3, 1B1, 1C4, 1E1) displayed significant sulfating activities toward rotigotine. pH dependence and kinetic parameters of the sulfation of rotigotine by relevant human SULTs were determined. Of the 6 human organ samples tested, small intestine and liver cytosols displayed considerably higher rotigotine-sulfating activity than did brain, lung, and kidney. Moreover, sulfation of rotigotine was shown to occur in HepG2 human hepatoma cells and Caco-2 human colon adenocarcinoma cells under metabolic conditions. Collectively, the results obtained provided a molecular basis underlying the previous finding of the excretion of sulfated rotigotine by patients undergoing treatment with rotigotine. [ABSTRACT FROM AUTHOR]

Various nitro- and aminotoluenes demonstrated carcinogenic activity in rodent studies, but were inactive or weakly active in conventional in vitro mutagenicity assays. Standard in vitro tests do not take into account activation by certain classes of enzymes. This is true in particular for sulfotransferases (SULTs). These enzymes may convert aromatic hydroxylamines and benzylic alcohols, two major classes of phase-I metabolites of nitro- and aminotoluenes, to reactive esters. Here it is shown that expression of certain human SULTs in Salmonella typhimurium TA1538 or TA100 strongly enhanced the mutagenicity of various nitrotoluenes and nitro- and amino-substituted benzyl alcohols. Human SULT1A1, SULT1A2, and SULT1C2 showed the strongest activation. The observation that some nitrotoluenes as well as some aminobenzyl alcohols were activated by SULTs in the absence of cytochromes P450 implies that mutagenic sulfuric esters were formed at both the exocyclic nitrogen and the benzylic carbon, respectively. Nitroreductase deficiency (using strain YG7131 instead of TA1538 for SULT1A1 expression) did not affect the SULT-dependent mutagenicity of 1-hydroxymethylpyrene (containing no nitro group), moderately enhanced that of 2-amino-4-nitrobenzyl alcohol, and drastically attenuated the effects of nitrobenzyl alcohols without other substituents. The last finding suggests that either activation occurred at the hydroxylamino group formed by nitroreductase or the nitro group (having a strong -M effect) had to be reduced to an electron-donating substituent to enhance the reactivity of the benzylic sulfuric esters. The results pointed to an important role of SULTs in the genotoxicity of nitrotoluenes and alkylated anilines. Activation occurs at nitrogen functions as well as benzylic positions. Environ. Mol. Mutagen. 57:299-311, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Sulphation is known to be critically involved in the metabolism of acetaminophen in vivo. This study aimed to systematically identify the major human cytosolic sulfotransferase (SULT) enzyme(s) responsible for the sulphation of acetaminophen. A systematic analysis showed that three of the twelve human SULTs, SULT1A1, SULT1A3 and SULT1C4, displayed the strongest sulphating activity towards acetaminophen. The pH dependence of the sulphation of acetaminophen by each of these three SULTs was examined. Kinetic parameters of these three SULTs in catalysing acetaminophen sulphation were determined. Moreover, sulphation of acetaminophen was shown to occur in HepG2 human hepatoma cells and Caco-2 human intestinal epithelial cells under the metabolic setting. Of the four human organ samples tested, liver and intestine cytosols displayed considerably higher acetaminophen-sulphating activity than those of lung and kidney. Collectively, these results provided useful information concerning the biochemical basis underlying the metabolism of acetaminophen in vivo previously reported. [ABSTRACT FROM AUTHOR]

Previous studies have demonstrated the metabolism of ritodrine through sulfation. The current study was designed to identify the human SULTs that are capable of sulfating ritodrine and to investigate how genetic polymorphism of the major ritodrine-sulfating SULT, SULT1A3, may affect its sulfating activity. A systematic analysis revealed that of the 13 known human SULTs, SULT1A1, SULT1A3, and SULT1C4, were capable of mediating the sulfation of ritodrine, with SULT1A3 displaying the strongest sulfating activity. Effects of genetic polymorphism on the sulfating activity of SULT1A3 were examined. By employing site-directed mutagenesis, 4 SULT1A3 allozymes were generated, expressed, and purified. Purified SULT1A3 allozymes were shown to exhibit differential sulfating activity toward ritodrine. Kinetic studies further demonstrated differential substrate affinity and catalytic efficiency among the SULT1A3 allozymes. Collectively, these results provided useful information concerning the differential metabolism of ritodrine through sulfation in different individuals. [ABSTRACT FROM AUTHOR]

The cytosolic sulfotransferases (SULTs) are dimeric enzymes that catalyze the transformation of hydrophobic drugs and hormones into hydrophilic sulfate esters thereby providing the body with an important pathway for regulating small molecule activity and excretion. While SULT dimerization is highly conserved, the necessity for the interaction has not been established. To perform its function, a SULT must efficiently bind the universal sulfate donor, 3'-phosphoadenosine- 5'-phosphosulfate (PAPS), and release the byproduct, 3', 5'-diphosphoadenosine (PAP), following catalysis. We hypothesize this efficient binding and release of PAPS/PAP may be connected to SULT dimerization. To allow for the visualization of dynamic protein interactions critical for addressing this hypothesis and to generate kinetically testable hypotheses, molecular dynamic simulations (MDS) of hSULT1B1 were performed with PAPS and PAP bound to each dimer subunit in various combinations. The results suggest the dimer subunits may possess the capability of communicating with one another in a manner dependent on the presence of the cofactor. PAP or PAPS binding to a single side of the dimer results in decreased backbone flexibility of both the bound and unbound subunits, implying the dimer subunits may not act independently. Further, binding of PAP to one subunit of the dimer and PAPS to the other caused increased flexibility in the subunit bound to the inactive cofactor (PAP). These results suggest SULT dimerization may be important in maintaining cofactor binding/release properties of SULTs and provide hypothetical explanations for SULT half-site reactivity and substrate inhibition, which can be analyzed in vitro. [ABSTRACT FROM AUTHOR]

The current study was designed to examine the sulfation of eight opioid drugs, morphine, hydromorphone, oxymorphone, butorphanol, nalbuphine, levorphanol, nalorphine, and naltrexone, in HepG2 human hepatoma cells and human organ samples (lung, liver, kidney, and small intestine) and to identify the human SULT(s) responsible for their sulfation. Analysis of the spent media of HepG2 cells, metabolically labeled with [35S]sulfate in the presence of each of the eight opioid drugs, showed the generation and release of corresponding [35S]sulfated derivatives. Five of the eight opioid drugs, hydromorphone, oxymorphone, butorphanol, nalorphine, and naltrexone, appeared to be more strongly sulfated in HepG2 cells than were the other three, morphine, nalbuphine, and levorphanol. Differential sulfating activities toward the opioid drugs were detected in cytosol or S9 fractions of human lung, liver, small intestine, and kidney, with the highest activities being found for the liver sample. A systematic analysis using eleven known human SULTs and kinetic experiment revealed SULT1A1 as the major responsible SULTs for the sulfation of oxymorphone, nalbuphine, nalorphine, and naltrexone, SULT1A3 for the sulfation of morphine and hydromorphone, and SULT2A1 for the sulfation of butorphanol and levorphanol. Collectively, the results obtained imply that sulfation may play a significant role in the metabolism of the tested opioid drugs in vivo. [ABSTRACT FROM AUTHOR]

1. This study elucidated the species differences between rats and humans in the inhibitory potential of drugs against sulfation and glucuronidation, and whether such differences depend on the inhibition parameter adopted. 2. With 14 non-steroidal anti-inflammatory drugs (NSAIDs) as model inhibitors and three flavanoids baicalein, wogonin and oroxylin A as model substrates, three common inhibition parameters percentage of control, IC50 and Ki were determined in rat liver cytosols (RLCs), human liver cytosols (HLCs), rat liver microsomes (RLMs) and human liver microsomes (HLMs). The closeness of the inhibition parameters from rat liver preparations to that from human liver preparations was analyzed by geometric mean fold error (GMFE) and statistical comparisons. 3. The percentage of control in RLC/RLM was not significantly different from that in HLC/HLM, with a GMFE of 0.85 (RLC-HLC) and 1.03 (RLM-HLM); whereas the IC50 and Ki in RLC/RLM were significantly different from that in HLC/HLM. The trend of difference was consistent between IC50 and Ki, where these parameters in RLC and RLM underestimated (GMFE <0.5) and overestimated (GMFE >2) that in HLC and HLM, respectively. 4. In conclusion, the inhibitory potentials of NSAIDs against sulfation and glucuronidation in rats and humans were different and depended on the adopted inhibition parameters. [ABSTRACT FROM AUTHOR]

[Display omitted] Many drug oxidations and conjugations are mediated by a variety of cytochromes P450 (P450) and non-P450 enzymes in humans and non-human primates. These non-P450 enzymes include aldehyde oxidases (AOX), carboxylesterases (CES), flavin-containing monooxygenases (FMO), glutathione S -transferases (GST), arylamine N -acetyltransferases (NAT),sulfotransferases (SULT), and uridine 5′-diphospho-glucuronosyltransferases (UGT) and their substrates include both endobiotics and xenobiotics. Cynomolgus macaques (Macaca fascicularis , an Old-World monkey) are widely used in preclinical studies because of their genetic and physiological similarities to humans. However, many reports have indicated the usefulness of common marmosets (Callithrix jacchus , a New World monkey) as an alternative non-human primate model. Although knowledge of the drug-metabolizing properties of non-P450 enzymes in non-human primates is relatively limited, new research has started to provide an insight into the molecular characteristics of these enzymes in cynomolgus macaques and common marmosets. This mini-review provides collective information on the isoforms of non-P450 enzymes AOX, CES, FMO, GST, NAT, SULT, and UGT and their enzymatic profiles in cynomolgus macaques and common marmosets. In general, these non-P450 cynomolgus macaque and marmoset enzymes have high sequence identities and similar substrate recognitions to their human counterparts. However, these enzymes also exhibit some limited differences in function between species, just as P450 enzymes do, possibly due to small structural differences in amino acid residues. The findings summarized here provide a foundation for understanding the molecular mechanisms of polymorphic non-P450 enzymes and should contribute to the successful application of non-human primates as model animals for humans. [ABSTRACT FROM AUTHOR]

Combined structure, function and molecular dynamics studies of human cytosolic sulfotransferases (SULT1A1 and 2A1) have revealed that these enzymes contain a ∼30-residue active-site cap whose structure responds to substrates and mediates their interactions. The binding of 3′-phosphoadenosine 5′-phosphosulfate (PAPS) gates access to the active site by a remodeling of the cap that constricts the pore through which acceptors must pass to enter the active site. While the PAPS-bound enzyme spends the majority (∼95%) of its time in the constricted state, the pore isomerizes between the open and closed states when the nucleotide (PAPS) is bound. The dimensions of the open and closed pores place widely different steric constraints on substrate selectivity. Nature appears to have crafted these enzymes with two specificity settings - a closed-pore setting that admits a set of closely related structures, and an open setting that allows a far wider spectrum of acceptor geometries. The specificities of these settings seem well matched to the metabolic demands for homeostatic and defensive SULT functions. The departure of nucleotide requires that the cap open. This isomerization dependent release can explain both the product bursts and substrate inhibition seen in many SULTs. Here, the experimental underpinnings of the cap-mechanism are reviewed, and the advantages of such a mechanism are considered in the context of the cellular and metabolic environment in which these enzymes operate. [ABSTRACT FROM AUTHOR]

The cytosolic sulfotransferases (SULTs) are a multigene family of enzymes that catalyze the transfer of a sulfonate group from the physiologic sulfate donor, 3′-phosphoadenosine-5′-phosphosulfate, to a nucleophilic substrate to generate a polar product that is more amenable to elimination from the body. As catalysts of both xenobiotic and endogenous metabolism, the SULTs are major points of contact between the external and physiological environments, and modulation of SULT-catalyzed metabolism can not only affect xenobiotic disposition, but it can also alter endogenous metabolic processes. Therefore, it is not surprising that SULT expression is regulated by numerous members of the nuclear receptor (NR) superfamily that function as sensors of xenobiotics as well as endogenous molecules, such as fatty acids, bile acids, and oxysterols. These NRs include the peroxisome proliferator-activated receptors, pregnane X receptor, constitutive androstane receptor, vitamin D receptor, liver X receptors, farnesoid X receptor, retinoid-related orphan receptors, and estrogen-related receptors. This review summarizes current information about NR regulation of SULT expression. Because species differences in SULT subfamily composition and tissue-, sex-, development-, and inducer-dependent regulation are prominent, these differences will be emphasized throughout the review. In addition, because of the central role of the SULTs in cellular physiology, the effect of NR-mediated SULT regulation on physiological and pathophysiological processes will be discussed. Gaps in current knowledge that require further investigation are also highlighted. [ABSTRACT FROM AUTHOR]

Feed additives such as ractopamine and salbutamol are pharmacologically active compounds, acting primarily as β-adrenergic agonists. This study was designed to investigate whether the sulfation of ractopamine and salbutamol may occur under the metabolic conditions and to identify the human cytosolic sulfotransferases (SULTs) that are capable of sulfating two major feed additive compounds, ractopamine and salbutamol. A metabolic labelling study showed the generation and release of [35S]sulfated ractopamine and salbutamol by HepG2 human hepatoma cells labelled with [35S]sulfate in the presence of these two compounds. A systematic analysis using 11 purified human SULTs revealed SULT1A3 as the major SULT responsible for the sulfation of ractopamine and salbutamol. The pH dependence and kinetic parameters were analyzed. Moreover, the inhibitory effects of ractopamine and salbutamol on SULT1A3-mediated dopamine sulfation were investigated. Cytosol or S9 fractions of human lung, liver, kidney and small intestine were examined to verify the presence of ractopamine-/salbutamol-sulfating activity in vivo. Of the four human organs, the small intestine displayed the highest activity towards both compounds. Collectively, these results imply that the sulfation mediated by SULT1A3 may play an important role in the metabolism and detoxification of ractopamine and salbutamol. [ABSTRACT FROM AUTHOR]

Abstract: By searching the GenBank database, we identified sequences encoding three new zebrafish cytosolic sulfotransferases (SULTs). These three new zebrafish SULTs, designated SULT1 ST9, SULT3 ST4, and SULT3 ST5, were cloned, expressed, purified, and characterized. SULT1 ST9 appeared to be mostly involved in the metabolism and detoxification of xenobiotics such as β-naphthol, β-naphthylamine, caffeic acid and gallic acid. SULT3 ST4 showed strong activity toward endogenous compounds such as dehydroepiandrosterone (DHEA), pregnenolone, and 17β-estradiol. SULT3 ST5 showed weaker, but significant, activities toward endogenous compounds such as DHEA and corticosterone, as well as xenobiotics including mestranol, β-naphthylamine, β-naphthol, and butylated hydroxyl anisole (BHA). pH-dependency and kinetic constants of these three enzymes were determined with DHEA, β-naphthol, and 17β-estradiol as substrates. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to examine the expression of these three new zebrafish SULTs at different developmental stages during embryogenesis, through larval development, and on to maturity. [Copyright &y& Elsevier]

Abstract: Steroids play important roles in regulating many physiological functions in marine and freshwater fish. Levels of active steroid in blood and tissues are determined by the balance between synthetic and catabolic processes. This review examines what is known about pathways of catabolism of steroids, primarily sex steroids, in marine and freshwater fish. Cytochrome P450 (P450) isoforms present in hepatic microsomes catalyze steroid hydroxylation to metabolites with lower or no activity at estrogen or androgen receptors. Important pathways of steroid catabolism to readily excreted metabolites are glucuronidation and sulfonation of hydroxyl groups. Estradiol, testosterone, DHEA and hydroxylated metabolites of these and other steroids readily form glucuronide and sulfate conjugates in those fish species where these pathways have been examined. Little is known, however, of the structure and function of the UDP-glucuronosyltransferase (UGT) and sulfotransferase (SULT) enzymes involved in steroid conjugation in fish. Glucuronide and sulfate conjugates of steroids may be transported into and out of cells by organic anion transporter proteins and multi-drug resistance proteins, and there is growing evidence that these proteins play important roles in steroid conjugate transport and elimination. Induction or inhibition of any of these pathways by environmental chemicals can result in alteration of the natural balance of steroid hormones and could lead to disruption of the endocrine system. Recent studies in this area are presented, with particular focus on phase II (conjugative) pathways. [Copyright &y& Elsevier]

Abstract: Large libraries of randomly mutated genes are applied in directed evolution experiments in order to obtain sufficient variability. These libraries, however, contain mostly inactive variants, and the very low frequency of improved variants can only be isolated by high-throughput screening. Small but efficient libraries comprise an attractive alternative. Here, we describe the application of ancestral libraries—libraries based on mutations predicted by phylogenetic analysis and ancestral inference. We designed and constructed such libraries using serum paraoxonases and cytosolic sulfotransferases (SULTs) as model enzymes. Both of these enzyme families exhibit a range of activities in drug metabolism and detoxification of xenobiotics. The ancestral serum paraoxonase and SULT libraries were screened by low-throughput means, including HPLC, using substrates and/or reactions with which all family members exhibit low activity. The libraries showed a remarkably high frequency of highly polymorphic and functionally diverse variants. Screening of as few as 300 variants enabled the isolation of mutants with up to 50-fold higher activity than the starting point enzyme. Structural and kinetic characterizations of an evolved SULT variant show how few ancestral mutations reshaped the active site and modulated the enzyme''s specificity. Ancestral libraries therefore comprise a means of focusing diversity to positions and mutations that readily trigger changes in substrate and/or reaction specificity, thereby facilitating the isolation of new enzyme variants for a variety of different substrates and reactions by medium-throughput or even low-throughput screens. [Copyright &y& Elsevier]

Background. Melatonin suppresses breast cancer cell proliferation by inhibiting the upregulation of estrogen-induced cyclin D1 via its G-protein-coupled receptor MT1. Additionally, melatonin stimulates the expression of the estrogen sulfotransferase, SULT1E1. However, metabolism of melatonin via 6-hydroxylation by CYP1A1/1A2 and subsequent sulfonation by SULT1A1/1A3 decreases its intracellular concentration. This could have a negative impact on its oncostatic action in breast cancer. Patients and methods. In this pilot study, we performed immunohistochemical (IHC) analysis of MT1 and cyclin D1 in breast cancer specimens from 33 patients. Also, we investigated the expression of CYP1A1/1A2, SULT1A1/1A3/1E1, and cyclin D1 in cancer (CANC) and adjacent non-cancer (NCANC) specimens from 10 representative breast cancer patients using quantitative real-time reverse transcription polymerase chain reaction. Results. CYP1A1-mRNA-expression was found only in three CANC and in one NCANC. CYP1A2 mRNA was below the detection limit in all patients. SULT1A1 was observed only in two of the 10 CANC and one of the 10 NCANC specimens. But, all 10 CANC and NCANC samples showed high SULT1A3 levels. Cyclin D1 mRNA levels were found in all 10 CANC and NCANC specimens. Furthermore, IHC-staining of cyclin D1 was observed in 27 of 33 CANC and correlated positively with estrogen receptor positivity ( p == 0.015). Conclusion. The low or even absent expression of CYP1A1 or CYP1A2 in breast cancer specimens suggested that melatonin might be involved in cell cycle arrest. [ABSTRACT FROM AUTHOR]

Marked gender differences in the expression of sulfotransferases (Sults) are known to exist in several species including rats, mice and hamsters. However, the mechanism for this gender difference is not known. Therefore, in the present study, it was determined whether sex and/or growth hormone (GH) are responsible for the gender difference in the expression of Sults using gonadectomized (GNX), hypophysectomized (HX) and GH-releasing hormone receptor-deficient little (lit/lit) mouse models. Sult1a1 and Papss2 in liver and kidney, and Sult1d1 in liver are female-predominant in mice because of suppressive effects of both androgens and male-pattern GH secretion. Sult2a1/a2 is the most markedly female-predominant Sult in mouse liver due to suppressive effects of androgens and male-pattern GH secretion, as well as stimulatory effects by estrogens and female-pattern GH secretion. Sult3a1 is female-predominant in mouse liver due to suppressive effects of androgens as well as stimulatory effects of estrogens and female-pattern GH secretion. Sult1c1 expression is male-predominant in mouse liver and kidney because of stimulatory effects of androgens in males. Sult4a1 expression is female-predominant in mouse brain due to stimulatory effects of estrogens. In conclusion, gender-divergent Sults are mostly female-predominant and Sult1c1 is the only male-dominant Sult. The gender differences in expression of various mouse Sults are influenced by various mechanisms involving sex and/or GHs. [ABSTRACT FROM AUTHOR]

Dextromethorphan is widely used in over-the-counter cough and cold medications. Its efficacy and safety for infants and young children remains to be clarified. The present study was designed to use zebrafish as a model to investigate the potential toxicity of dextromethorphan during embryonic and larval development. Three sets of zebrafish embryos/larvae were exposed to dextromethorphan at 24, 48 and 72 h post fertilization (hpf), respectively, during the embryonic/larval development. Compared with the 48 and 72 hpf exposure sets, the embryos/larvae in the 24 hpf exposure set showed much higher mortality rates which increased in a dose-dependent manner. Bradycardia and reduced blood flow were observed for the embryos/larvae treated with increasing concentrations of dextromethorphan. Morphological effects of dextromethorphan exposure, including yolk sac and cardiac edema, craniofacial malformation, lordosis, non-inflated swim bladder and missing gill, were also more frequent and severe among zebrafish embryos/larvae exposed to dextromethorphan at 24 hpf. Whether the more frequent and severe developmental toxicity of dextromethorphan observed among the embryos/larvae in the 24 hpf exposure set, as compared with the 48 and 72 hpf exposure sets, is due to the developmental expression of the phase I and phase II enzymes involved in the metabolism of dextromethorphan remains to be clarified. A reverse transcription-polymerase chain reaction analysis, nevertheless, revealed developmental stage-dependent expression of mRNAs encoding SULT3 ST1 and SULT3 ST3, two enzymes previously shown to be capable of sulfating dextrorphan, an active metabolite of dextromethorphan. Copyright © 2010 John Wiley & Sons, Ltd. The zebrafish was used as a model to investigate the toxicity of dextromethorphan during the embryonic and larval development. Bradycardia and reduced blood flow were observed for the embryos/larvae treated with increasing concentrations of dextromethorphan. Morphological effects of dextromethorphan exposure, including yolk sac and cardiac edema, craniofacial malformation, lordosis, non-inflated swim bladder, and missing gill, were also observed. [ABSTRACT FROM AUTHOR]

Hepatocyte nuclear factor 4 alpha (HNF4a) is a liver-enriched master regulator of liver function. HNF4a is important in regulating hepatic expression of certain cytochrome P450s. The purpose of this study was to use mice lacking HNF4a expression in liver (HNF4a-HNull) to elucidate the role of HNF4a in regulating hepatic expression of phase II enzymes and transporters in mice. Compared with male wild-type mice, HNF4a-HNull male mouse livers had (1) markedly lower messenger RNAs (mRNAs) encoding the uptake transporters sodium taurocholate cotransporting polypeptide, organic anion transporting polypeptide (Oatp) 1a1, Oatp2b1, organic anion transporter 2, sodium phosphate cotransporter type 1, sulfate anion transporter 1, sodium-dependent vitamin C transporter 1, the phase II enzymes Uridine 5′-diphospho (UDP)-glucuronosyltransferase (Ugt) 2a3, Ugt2b1, Ugt3a1, Ugt3a2, sulfotransferase (Sult) 1a1, Sult1b1, Sult5a1, the efflux transporters multidrug resistance–associated protein (Mrp) 6, and multidrug and toxin extrusion 1; (2) moderately lower mRNAs encoding Oatp1b2, organic cation transporter (Oct) 1, Ugt1a5, Ugt1a9, glutathione S-transferase (Gst) m4, Gstm6, and breast cancer resistance protein; but (3) higher mRNAs encoding Oatp1a4, Octn2, Ugt1a1, Sult1e1, Sult2a2, Gsta4, Gstm1-m3, multidrug resistance protein (Mdr) 1a, Mrp3, and Mrp4. Hepatic signaling of nuclear factor E2–related factor 2 and pregnane X receptor appear to be activated in HNF4a-HNull mice. In conclusion, HNF4a deficiency markedly alters hepatic mRNA expression of a large number of phase II enzymes and transporters, probably because of the loss of HNF4a, which is a transactivator and a determinant of gender-specific expression and/or adaptive activation of signaling pathways important in hepatic regulation of these phase II enzymes and transporters. [ABSTRACT FROM AUTHOR]