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Background Leafy greens are responsible for nearly half of the produce-related Shiga toxin-producing Escherichia coli (STEC) outbreaks in the United States and recent investigations have implicated agricultural water as a potential source. Current FDA detection protocols require extensive analysis time. Development of methods for rapid detection of STECs in the field are imperative to maintain food safety. We aimed to use Oxford Nanopore rapid sequencing kits for an in-field determination of agricultural water microbiome and possible detection and characterization of STECs strain(s) in these samples. Results We tested the performance of the nanopore rapid sequencing kit (RAD004) for fast microbiome determination using the well characterized ZymoBIOMICS mock microbial community and the number of reads for each identified species was present in the expected proportion. Rapid sequencing kit (LRK001 and RAD004) library preparation of DNA extracted from agricultural water resulted in poor nanopore sequencing reactions, with low output (0.3–1.7 M reads), a high proportion of failed reads (50–60%), and highly sheared DNA before and after a magnetic bead clean up. To improve performance, we prepared a DNA library with the ligation kit (LSK109), which includes multiple cleaning steps, reducing inherent inhibitors and producing a better outcome (2.2 M reads, 15% failed reads). Metagenomic composition of four sample sites determined using the ligation kit, showed a highly diverse bacterial community for each site, with 11 total genera identified, including Synechococcus and Cyanobium. No definitive presence of STEC could be confirmed in any of the sites. Approximately 100 reads from each site (0.02% of total reads) were identified as Escherichia coli, but the specific strain or their virulence genes could not be detected. Sites 9, 10, and 12 were found to be positive for STEC presence by microbiological techniques after enrichment. Conclusions The rapid sequencing kits can be appropriate for genus or species level microbial identification, but we recommend the use of the ligation kit for increased sequencing depth and removal of contaminants in agricultural water. However, we were not able to identify any STEC strains in these nanopore microbiome samples, due to low initial concentrations. The results from this pilot study provide preliminary evidence that MinION sequencing of agricultural water using the ligation kit has the potential to be used for rapid microbiome determination in the field with optimal results for water quality surveillance.

This study was conducted to determine the phylogenies of Salmonella strains isolated from cross-sectional studies conducted at hatcheries, broiler farms, processing plants, and retail outlets (broiler production chain) in Trinidad and Tobago over 4 yr (2016-2019). Whole-genome sequencing (WGS) was used to characterize Salmonella isolates. Core genome phylogenies of 8 serovars of public health significance were analyzed for similarities in origin and relatedness. In addition, Salmonella strains isolated from human salmonellosis cases in Trinidad were analyzed for their relatedness to the isolates detected along the broiler production chain. The common source of these isolates of diverse serovars within farms, within processing plants, between processing plants and retail outlets, and among farm-processing plant-retail outlet continuum was well-supported (bootstrap value70%) by the core genome phylogenies for the respective serovars. Also, genome analyses revealed clustering of Salmonella serovars of regional (intra-Caribbean) and international (extra-Caribbean) origin. Similarly, strains of S. Enteritidis and S. Infantis isolated from human clinical salmonellosis in 2019 from Trinidad and Tobago clustered with our processing plant isolates recovered in 2018. This study is the first phylogenetic analysis of Salmonella isolates using WGS from the broiler industry in the Caribbean region. The use of WGS confirmed the genetic relatedness and transmission of Salmonella serovars contaminating chickens in broiler processing, and retailing in the country, with zoonotic and food safety implications for humans.

Mitochondrial adaptation during non-alcoholic fatty liver disease (NAFLD) include remodeling of ketogenic flux and sustained tricarboxylic acid (TCA) cycle activity, which are concurrent to onset of oxidative stress. Over 70% of obese humans have NAFLD and ketogenic diets are common weight loss strategies. However, the effectiveness of ketogenic diets toward alleviating NAFLD remains unclear. We hypothesized that chronic ketogenesis will worsen metabolic dysfunction and oxidative stress during NAFLD. Mice (C57BL/6) were kept (for 16-wks) on either a low-fat, high-fat, or high-fat diet supplemented with 1.5X branched chain amino acids (BCAAs) by replacing carbohydrate calories (ketogenic). The ketogenic diet induced hepatic lipid oxidation and ketogenesis, and produced multifaceted changes in flux through the individual steps of the TCA cycle. Higher rates of hepatic oxidative fluxes fueled by the ketogenic diet paralleled lower rates of de novo lipogenesis. Interestingly, this metabolic remodeling did not improve insulin resistance, but induced fibrogenic genes and inflammation in the liver. Under a chronic “ketogenic environment,” the hepatocyte diverted more acetyl-CoA away from lipogenesis toward ketogenesis and TCA cycle, a milieu which can hasten oxidative stress and inflammation. In summary, chronic exposure to ketogenic environment during obesity and NAFLD has the potential to aggravate hepatic mitochondrial dysfunction.

This cross-sectional study determined the serovars, antimicrobial resistance genes, and virulence factors of

During the normal embryonic-to-neonatal development, the chicken liver is subjected to intense lipid burden from high rates of yolk-lipid oxidation and also from the accumulation of the yolk-derived and newly synthesized lipids from carbohydrates. High rates of hepatic lipid oxidation and lipogenesis are also central features of non-alcoholic fatty liver disease (NAFLD) in both rodents and humans, but is associated with impaired insulin signaling, dysfunctional mitochondrial energetics and oxidative stress. However, these adverse effects are not apparent in the liver of embryonic and neonatal chicken, despite lipid burden. Utilizing comprehensive metabolic profiling, we identify that steady induction of hepatic mitochondrial tricarboxylic acid (TCA) cycle and lipogenesis are central features of embryonic-to-neonatal transition. More importantly, the induction of TCA cycle and lipogenesis occurred together with the downregulation of hepatic β-oxidation and ketogenesis in the neonatal chicken. This synergistic remodeling of hepatic metabolic networks blunted inflammatory onset, prevented accumulation of lipotoxic intermediates (ceramides and diacylglycerols) and reduced reactive oxygen species production during embryonic-to-neonatal development. This dynamic remodeling of hepatic mitochondrial oxidative flux and lipogenesis aids in the healthy embryonic-to-neonatal transition in chicken. This natural physiological system could help identify mechanisms regulating mitochondrial function and lipogenesis, with potential implications towards treatment of NAFLD.

This research examines the role of personality traits beyond the Five-Factor Model (FFM) framework in predicting pro-environmental values and behaviors. A sample of 410 participants completed personality scales and reported both their environmental values and the extent to which they had engaged in a series of pro-environmental behaviors in the preceding 24 h. Small positive correlations were found between environmental values and behaviors with integrity and femininity and negative correlations with religiosity. Overall, the results show limited evidence supporting the personality dimensions measured in predicting pro-environmental values and behaviors. Implications of the findings are discussed.

Salmonella enterica is an important foodborne pathogen worldwide. We used long and short read sequencing to close genomes of eight multidrug resistant (MDR) Salmonella enterica strains, belonging to serovars Infantis (2), Albany, Oranienburg, I 4,[5],12:i:-, Javiana, Schwarzengrund, and Kentucky from broiler chicken farms and processing plants in Trinidad and Tobago. They also belonged to seven different sequence types (STs- 32, 292, 1510, 19, 24, and 96). Seven of the strains demonstrated multi-drug resistance with the presence of at least three AMR genes. Three isolates contained the quinolone resistance gene qnrB19 in plasmids (CFSAN103840, CFSAN103854, and CFSAN103872). The extended spectrum β-lactamase genes blaCTX-M-65 (CFSAN103796) and blaTEM-1 (CFSAN103852) were detected in this study. The genomes closed in this study will be useful for future source tracking and outbreak investigations in Trinidad and Tobago and worldwide.

Shiga toxin-producing Escherichia coli (STEC) contamination of agricultural water might be an important factor to recent foodborne illness and outbreaks involving leafy greens. Whole genome sequencing generation of closed bacterial genomes plays an important role in source tracking. We aimed to determine the limits of detection and classification of STECs by qPCR and nanopore sequencing using enriched irrigation water artificially contaminated with E. coli O157:H7 (EDL933). We determined the limit of STEC detection by qPCR to be 30 CFU/reaction, which is equivalent to 105 CFU/ml in the enrichment. By using Oxford Nanopore’s EPI2ME WIMP workflow and de novo assembly with Flye followed by taxon classification with a k-mer analysis software (Kraken), E. coli O157:H7 could be detected at 103 CFU/ml (68 reads) and a complete fragmented E. coli O157:H7 metagenome-assembled genome (MAG) was obtained at 105-108 CFU/ml. Using a custom script to extract the E. coli reads, a completely closed MAG was obtained at 107-108 CFU/ml and a complete, fragmented MAG was obtained at 105-106 CFU/ml. In silico virulence detection for E. coli MAGs for 105-108 CFU/ml showed that the virulotype was indistinguishable from the spiked E. coli O157:H7 strain. We further identified the bacterial species in the un-spiked enrichment, including antimicrobial resistance genes, which could have important implications to food safety. We propose this workflow could be used for detection and complete genomic characterization of STEC from a complex microbial sample and could be applied to determine the limit of detection and assembly of other foodborne bacterial pathogens.IMPORTANCEFoodborne illness caused by Shiga toxin-producing E. coli (STEC) ranges in severity from diarrhea to hemolytic uremic syndrome and produce-related incidence is increasing. The pervasive nature of E. coli requires not only detection, but also a complete genome to determine potential pathogenicity based on stx and eae genes, serotype, and other virulence factors. We have developed a pipeline to determine the limits of nanopore sequencing for STECs in a metagenomic sample. By utilizing the current qPCR in the FDA Bacteriological Analytical Manual (BAM) Chapter 4A, we can quantify the amount of STEC in the enrichment and then sequence and classify the STEC in less than half the time as current protocols that require a single isolate. These methods have wide implications for food safety, including decreased time to STEC identification during outbreaks, characterization of the microbial community, and the potential to use these methods to determine the limits for other foodborne pathogens.

Since 2000, reports have documented the challenges faced by many Americans in receiving oral health care and the consequences of inadequate care such as high levels of dental caries among many U.S. children. To help address this problem, many dental schools now include community-based dental education (CBDE) in their curricula, placing students in extramural clinics where they provide care in underserved communities. CBDE is intended to both broaden the education of future oral health professionals and expand care for patients in community clinics. The aim of this study was to develop a three-year profile of the patients seen and the care provided by students at extramural clinics associated with one U.S. dental school. Three student cohorts participated in the rotations: final-year students in the Doctor of Dental Surgery, Bachelor of Science in Dental Hygiene, and Master of Dental Therapy programs. The study was a retrospective analysis of data retrieved from the school's database for three consecutive academic years. The data included patients' demographics and special health care needs status (based on information collected by students from their patients) and procedures students performed while on rotations. For the three-year period, the results showed a total of 43,128 patients were treated by 418 student providers. Approximately 25% of all encounters were with pediatric patients. Students completed 5,908 child prophylaxis, 5,386 topical fluoride varnish, and 7,678 sealant procedures on pediatric patients. Annually, 7% of the total patients treated had special health care needs. The results show that these students in CBDE rotations provided a substantial amount of oral health care at extramural sites and gained additional experience in caring for a diverse population of patients and performing a wide range of procedures.

For mice, a maternal vitamin A (VA) deficient diet initiated from mid-gestation (GVAD) produces serum retinol deficiency in mature offspring. We hypothesize that the effects of GVAD arise from pre-weaning developmental changes. We compare the effect of this GVAD protocol in combination with a post-weaning high fat diet (HFD) or high carbohydrate diet (LF12). Each is compared to an equivalent VA sufficient combination. GVAD extensively decreased serum retinol and liver retinol, retinyl esters, and retinoid homeostasis genes (Lrat, Cyp26b1, and Cyp26a1). These suppressions were each more effective with LF12 than with HFD. Post-weaning initiation of VA deficiency with LF12 depleted liver retinoids, but serum retinol was unaffected. Liver retinoid depletion, therefore, precedes serum attenuation. Maternal LF12 decreased the obesity response to the HFD, which was further decreased by GVAD. LF12 fed to the mother and offspring extensively stimulated genes marking stellate activation (Col1a1, Timp2, and Cyp1b1) and novel inflammation markers (Ly6d, Trem2, Nupr1). The GVAD with LF12 diet combination suppressed these responses. GVAD in combination with the HFD increased these same clusters. A further set of expression differences on the HFD when compared to a high carbohydrate diet were prevented when GVAD was combined with HFD. Most of these GVAD gene changes match published effects from deletion of Nr0b2/Shp, a retinoid-responsive, nuclear co-repressor that modulates metabolic homeostasis. The stellate and inflammatory increases seen with the high carbohydrate, LF12 diet may represent postprandial responses. They depend on retinol and Shp, but the regulation reverses with a HFD.

Community-based dental education (CBDE) has the potential to positively impact the educational process in a manner that both contributes to educational outcomes and shapes the learner's behavior. The aim of this study was to determine the correlation between dental students' intended practice location and the size of their hometown and to assess any impact their CBDE rotation in a rural location had on practice location intention. From March 7, 2016, to August 12, 2018, fourth-year students at one U.S. dental school were invited to complete a ten-item questionnaire prior to and after their four-week clinical rotations at a rural clinic. Of the 123 dental students on rotation at the clinic during this time, 106 completed the pre-rotation survey and 112 the post-rotation survey, for response rates of 86% and 91%, respectively. Prior to the rotation, 58.6% selected one of the rural locations as an ideal practice location, and that percentage increased slightly to 61.4% after the rotation; the difference was not statistically significant (p=0.984). The results did show a significant increase from pre to post rotation for women intending to practice in rural communities (p=0.0413). This study found that students' intent to practice in a rural location was not significantly affected by a clinical rotation in a rural clinic; however, there was strong evidence that students from rural communities intended to practice in rural communities after graduation.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants that are metabolized to carcinogenic dihydrodiol epoxides (PAHDE) by cytochrome P450 1B1 (CYP1B1). This metabolism occurs in bone marrow (BM) mesenchymal stem cells (MSC), which sustain hematopoietic stem and progenitor cells (HSPC). In BM, CYP1B1-mediated metabolism of 7, 12-dimethylbenz[a]anthracene (DMBA) suppresses HSPC colony formation within 6 h, whereas benzo(a)pyrene (BP) generates protective cytokines. MSC, enriched from adherent BM cells, yielded the bone marrow stromal, BMS2, cell line. These cells express elevated basal CYP1B1 that scarcely responds to Ah receptor (AhR) inducers. BMS2 cells exhibit extensive transcriptome overlap with leptin receptor positive mesenchymal stem cells (Lepr+ MSC) that control the hematopoietic niche. The overlap includes CYP1B1 and the expression of HSPC regulatory factors (Ebf3, Cxcl12, Kitl, Csf1 and Gas6). MSC are large, adherent fibroblasts that sequester small HSPC and macrophage in the BM niche (Graphic abstract). High basal CYP1B1 expression in BMS2 cells derives from interactions between the Ah-receptor enhancer and proximal promoter SP1 complexes, boosted by autocrine signaling. PAH effects on BMS2 cells model Lepr+MSC niche activity. CYP1B1 metabolizes DMBA to PAHDE, producing p53-mediated mRNA increases, long after the in vivo HSPC suppression. Faster, direct p53 effects, favored by stem cells, remain possible PAHDE targets. However, HSPC regulatory factors remained unresponsive. BP is less toxic in BMS2 cells, but, in BM, CYP1A1 metabolism stimulates macrophage cytokines (Il1b > Tnfa> Ifng) within 6 h. Although absent from BMS2 and Lepr+MSC, their receptors are highly expressed. The impact of this cytokine signaling in MSC remains to be determined., Graphic abstract HSPC, in vivo, are controlled in the BM vascular niche by Lepr+MSC. The mouse BMS2 line models Lepr+MSC regulation, with parallel CYP1B1, HSPC support factors (Cxcl12, Kitl, Ebf3) and cytokine receptor expression. PAHs can produce opposing effects. Rapid suppression of HSPC, effected by CYP1B1-mediated PAH metabolism to PAHDE in MSC (blue), is marked in BMS2 cells by p53-mediated gene activations (DMBA> > BP). Protection arises from in vivo BP metabolism by CYP1A1 that stimulates cytokines from local macrophage (Il1b, Tnf, Ifng), each with corresponding Lepr+MSC receptors. PAH quinones are the probable CYP1A1-mediated protectants.Unlabelled Image, Highlights • BMS2 and Lepr+MSC cells co-express CYP1B1 and 12 functional niche activity markers. • CYP1B1 mRNA in BMS2 cells depends on activation of SP1 coupled to an AhR enhancer unit. • DMBA metabolism by CYP1B1 activates p53 gene targets in BMS2 cells far more than BP. • HSPC suppression by CYP1B1 generation of PAHDE requires rapid, non-genomic targets. • BMS2 and Lepr+MSC share receptors activated by BP stimulation of macrophage cytokines.

BackgroundCytochrome P450 1b1 (Cyp1b1) deletion and dietary retinol deficiency during pregnancy (GVAD) affect perinatal liver functions regulated by Srebp. Cyp1b1 is not expressed in perinatal liver but appears in the E9.5 embryo, close to sites of retinoic acid (RA) signaling.HypothesisParallel effects of Cyp1b1 and retinol on postnatal Srebp derive from effects in the developing liver or systemic signaling.ApproachCluster postnatal increases in hepatic genes in relation to effects of GVAD or Cyp1b1 deletion. Sort expression changes in relation to genes regulated by Srebp1 and Srebp2.Test these treatments on embryos at E9.5, examining changes at the site of liver initiation. Use in situ hybridization to resolve effects on mRNA distributions of Aldh1a2 and Cyp26a1 (RA homeostasis); Hoxb1 and Pax6 (RA targets). Assess mice lacking Lrat and Rbp4 (DKO mice) that severely limits retinol supply to embryos.ResultsAt birth, GVAD and Cyp1b1 deletion stimulate gene markers of hepatic stellate cell (HSC) activation but also suppress Hamp. These treatments then selectively prevent the postnatal onset of genes that synthesize cholesterol (Hmgcr, Sqle) and fatty acids (Fasn, Scd1), but also direct cholesterol transport (Ldlr, Pcsk9, Stard4) and retinoid synthesis (Aldh1a1, Rdh11). Extensive support by Cyp1b1 is implicated, but with distinct GVAD interventions for Srebp1 and Srebp2. At E9.5, Cyp1b1 is expressed in the septum transversum mesenchyme (STM) with β-carotene oxygenase (Bco1) that generates retinaldehyde. STM provides progenitors for the HSC and supports liver expansion. GVAD and Cyp1b1-/- do not affect RA-dependent Hoxb1 and Pax6. In DKO embryos, RA-dependent Cyp26a1 is lost but Hoxb1 is sustained with Cyp1b1 at multiple sites.ConclusionCyp1b1-/- suppresses genes supported by Srebp. GVAD effects distinguish Srebp1 and Srebp2 mediation. Srebp regulation overlaps appreciably in cholesterol and retinoid homeostasis. Bco1/Cyp1b1 partnership in the STM may contribute to this later liver regulation.

OBJECTIVES: Elevated circulating branched chain amino acid (BCAA) levels are correlated with the development of insulin resistance and type 2 diabetes mellitus in humans. On the other hand, BCAA supplementation has been shown to be beneficial in improving insulin resistance during chronic liver disease. Furthermore, there is recent evidence of significant crosstalk between BCAA and mitochondrial lipid metabolism. Considering the central role of dysfunctional mitochondrial lipid metabolism in diet-induced obesity and non-alcoholic fatty liver disease (NAFLD), our objective was to determine the impact of dietary BCAA supplementation on hepatic mitochondrial function, in a diet-induced mouse model of NAFLD. We hypothesized that the dietary supplementation of BCAA, together with a high fat diet, will exacerbate hepatic mitochondrial dysfunction during NAFLD. METHODS: C57BL/6NJ mice were fed with a control (10% kcal fat), high fat (HF; 60% kcal fat), or HF diet supplemented with BCAA (BA; 60% kcal fat; 1.5X BCAA) diet for 16 weeks. Livers from these mice were used for mitochondrial isolation, total liver and mitochondrial protein estimation, determination of amino acids and Kreb's cycle intermediates by mass spectrometry, and gene expression profiles. RESULTS: While the liver weights (g ± SEM) of HF fed mice (2.6 ± 0.36) were significantly higher than the control mice (1.5 ± 0.19), BCAA supplemented mice had significantly lower liver weights than the HF fed mice (1.8 ± 0.28). Hepatic mitochondrial protein content (µg/g liver ± SEM) was enriched in BCAA supplemented mice compared to their HF diet fed counterparts (BA, 3858 ± 476; HF, 2635 ± 394; P ˂ 0.05). Many of the organic acid intermediates of the Kreb's cycle were significantly lower in the liver of HF fed mice. Interestingly, BCAA supplementation (BA) with HF feeding restored hepatic organic acid intermediates to similar levels observed in control mice. Further, HF and BA feeding, both downregulated lipogenic gene expression (e.g., Fasn, Scd1, Acly) in the liver. CONCLUSIONS: Our results suggest that BCAA supplementation enhanced hepatic mitochondrial biogenesis and oxidative metabolism in the liver of mice with NAFLD. High-fat diets which significantly suppressed the rates of de novo lipogenesis, could have provided the BCAAs, a metabolic milieu favorable for the induction of mitochondrial activity. FUNDING SOURCES: National Institutes of Health (R01).

OBJECTIVES: With 90% of the energy derived from yolk lipid oxidation in late-term embryos, and the dramatic induction of lipogenesis post-hatch, the liver is subjected to intense lipid burden during embryonic to post-hatch transition in chicken. Interestingly, unlike in rodents and humans with non-alcoholic fatty liver disease, this metabolic milieu in chicken embryos and hatchlings is not thought to promote metabolic syndrome or oxidative stress. We hypothesized that the optimal coupling of hepatic mitochondrial oxidative metabolism and lipogenesis will support insulin signaling and prevent onset of oxidative stress. METHODS: Fertile eggs (64 ± 3 g) were incubated at 38 °C and 45% relative humidity. At embryonic days (e), e14, e18 and post-hatch days (ph), ph3 and ph7, serum and tissues were collected for metabolic analysis. Hepatic mitochondria was isolated and incubated with [(13)C(3)]pyruvate to determine tricarboxylic acid (TCA) cycle activity and reactive oxygen species (ROS) production. RESULTS: Serum ketones (µM ± SEM) were significantly higher (P

OBJECTIVES: Plasma branched-chain amino acids (BCAAs; leucine, isoleucine, and valine) are elevated during insulin resistance and are robust predictors of future onset of type 2 diabetes mellitus (T2DM). Further, recent evidence points to a significant cross talk between BCAAs and lipid metabolism, which is disrupted during lipid metabolic disorders. Indeed, dysfunctional mitochondrial lipid metabolism is a central feature of non-alcoholic fatty liver disease (NAFLD). Considering the metabolic and molecular mechanisms of BCAA action on central metabolic pathways, we hypothesized that excess BCAAs during insulin resistance can interfere with mitochondrial function, by altering lipid oxidation, gluconeogenesis, and insulin signaling in the liver. METHODS: Mice (C57BL/6) were either fed a control (10% kcal from fat) or high fat (HF; 60% kcal from fat) diet for 16 weeks. Mice were then overnight fasted and challenged with either a saline or BCAA infusion (15.59 µmole/hour) for 8-hrs. Glucose and ketone turnover rates were determined from the dilution of [(13)C(6)]glucose and [(13)C(4)]3-hydroxybutyrate tracers. Plasma and tissues were collected and stored for metabolic profiling and gene and protein expression analysis. RESULTS: Infusion of BCAAs in mice resulted in a 2-fold elevation of circulating BCAAs (Control 179 ± 7 µM vs. 375 ± 21 µM, P

Cyp1b1 deletion and gestational vitamin A deficiency (GVAD) redirect adult liver gene expression. A matched sufficient pre- and post-natal diet, which has high carbohydrate and normal iron content (LF12), increased inflammatory gene expression markers in adult livers that were suppressed by GVAD and Cyp1b1 deletion. At birth on the LF12 diet, Cyp1b1 deletion and GVAD each suppress liver expression of the iron suppressor, hepcidin (Hepc), while increasing stellate cell activation markers and suppressing post-natal increases in lipogenesis. Hepc was less suppressed in Cyp1b1−/− pups with a standard breeder diet, but was restored by iron supplementation of the LF12 diet. Conclusions . The LF12 diet delivered low post-natal iron and attenuated Hepc. Hepc decreases in Cyp1b1−/− and GVAD mice resulted in stellate activation and lipogenesis suppression. Endothelial BMP6, a Hepc stimulant, is a potential coordinator and Cyp1b1 target. These neonatal changes in Cyp1b1−/− mice link to diminished adult obesity and liver inflammation.

Cytochrome P450 1b1 (Cyp1b1) is expressed in endothelia, stellate cells and pre-adipocytes, but not hepatocytes. Deletion alters liver fatty acid metabolism and prevents obesity and hepatic steatosis. This suggests a novel extra-hepatocyte regulation directed from cells that express Cyp1b1. To characterize these mechanisms, microarray gene expression was analyzed in livers of normal and congenic Cyp1b1-ko C57BL/6 J mice fed either low or high fat diets. Cyp1b1-ko gene responses indicate suppression of endogenous PPARα activity, a switch from triglyceride storage to mitochondrial fatty acid oxidation and decreased oxidative stress. Many gene responses in Cyp1b1-ko are sexually dimorphic and correspond to increased activity of growth hormone mediated by HNF4α. Male responses stimulated by GH pulses are enhanced, whereas responses that decline exhibit further suppression, including Cyp regulation by PPARα, CAR and PXR. These effects of Cyp1b1 deletion overlap with effects caused by deletion of the small heterodimeric partner, a suppressor of these nuclear factors. Redirection of gene expression associated with liver fat homeostasis in Cyp1b1-ko mice that directs hypothalamic control of GH and leptin. Cyp1b1-ko suppresses neonatal Scd1 and delays adult maturation of dimorphic GH/HNF4α signaling. Alternatively, deletion may diminish hypothalamic metabolism of estradiol, which establishes adult GH regulation.