Molecular-Sensory Decoding of the Citrus latifolia Aroma.

A modified aroma extract dilution approach (AEDA), followed by the determination of flavor dilution (FD) factors, a quantitative analysis and calculation of the relative flavor activity (RFA) and odor activity values (OAVs) as well as recombination experiments were conducted to evaluate the odor- and taste-relevant components of cold-pressed Citrus latifolia peel oil. A 2-fold concentration by distillation and reanalysis, compared with the original oil, revealed relevant components. Partition of the odor-active substances into four reconstitution groups according to their respective FD factors, followed by a recombination, allowed for a better understanding of the contribution of each FD-factor group to the overall aroma. Especially α-pinene, limonene, γ-terpinene, and 7-methoxycoumarin contribute significantly to the distinct aroma profile of C. latifolia. Heptadecanal (CAS 629-90-3) was described for the first time as an odor-active substance in an enriched C. latifolia peel oil. Campherenyl acetate (CAS 18530-07-9) was identified in nature for the first time and described with a herbal, minty and citrus-like odor. The odor profile of the final recombinant mixture, containing 36 components, was similar to cold-pressed C. latifolia peel oil for most descriptors, whereas the taste profile was described as more aldehydic and citral-like.

Separation of Dihydro-Isocoumarins and Dihydro-Stilbenoids from Hydrangea macrophylla ssp. serrata by Use of Counter-Current Chromatography.

Previously, different Hydrangea macrophylla ssp. serrata cultivars were investigated by untargeted LC-MS analysis. From this, a list of tentatively identified and unknown compounds that differ significantly between these cultivars was obtained. Due to the lack of reference compounds, especially for dihydro-isocoumarins, we aimed to isolate and structurally characterise these compounds from the cultivar 'Yae-no-amacha' using NMR and LC-MS methods. For purification and isolation, counter-current chromatography was used in combination with reversed-phase preparative HPLC as an orthogonal and enhanced purification workflow. Thirteen dihydro-isocoumarins in combination with other metabolites could be isolated and structurally identified. Particularly interesting was the clarification of dihydrostilbenoid glycosides, which were described for the first time in H. macrophylla ssp. serrata. These results will help us in further studies on the biological interpretation of our data.

Discovery of Novel Bacterial Chalcone Isomerases by a Sequence-Structure-Function-Evolution Strategy for Enzymatic Synthesis of (S)-Flavanones.

Chalcone isomerase (CHI) is a key enzyme in the biosynthesis of flavonoids in plants. The first bacterial CHI (CHIera ) was identified from Eubacterium ramulus, but its distribution, evolutionary source, substrate scope, and stereoselectivity are still unclear. Here, we describe the identification of 66 novel bacterial CHIs from Genbank using a novel Sequence-Structure-Function-Evolution (SSFE) strategy. These novel bacterial CHIs show diversity in substrate specificity towards various hydroxylated and methoxylated chalcones. The mutagenesis of CHIera according to the substrate binding models of these novel bacterial CHIs resulted in several variants with greatly improved activity towards these chalcones. Furthermore, the preparative scale conversion catalyzed by bacterial CHIs has been performed for five chalcones and revealed (S)-selectivity with up to 96 % ee, which provides an alternative biocatalytic route for the synthesis of (S)-flavanones in high yields.

Ancestral regulatory mechanisms specify conserved midbrain circuitry in arthropods and vertebrates.

Corresponding attributes of neural development and function suggest arthropod and vertebrate brains may have an evolutionarily conserved organization. However, the underlying mechanisms have remained elusive. Here, we identify a gene regulatory and character identity network defining the deutocerebral-tritocerebral boundary (DTB) in Drosophila This network comprises genes homologous to those directing midbrain-hindbrain boundary (MHB) formation in vertebrates and their closest chordate relatives. Genetic tracing reveals that the embryonic DTB gives rise to adult midbrain circuits that in flies control auditory and vestibular information processing and motor coordination, as do MHB-derived circuits in vertebrates. DTB-specific gene expression and function are directed by cis-regulatory elements of developmental control genes that include homologs of mammalian Zinc finger of the cerebellum and Purkinje cell protein 4Drosophila DTB-specific cis-regulatory elements correspond to regulatory sequences of human ENGRAILED-2, PAX-2, and DACHSHUND-1 that direct MHB-specific expression in the embryonic mouse brain. We show that cis-regulatory elements and the gene networks they regulate direct the formation and function of midbrain circuits for balance and motor coordination in insects and mammals. Regulatory mechanisms mediating the genetic specification of cephalic neural circuits in arthropods correspond to those in chordates, thereby implying their origin before the divergence of deuterostomes and ecdysozoans.

Investigations into the Natural Occurrence of 1-Phenylethyl Acetate (Styrallyl Acetate).

So far, the occurrence of the flavor constituent 1-phenylethyl acetate in a natural source has not been unambiguously confirmed. The present work provides the detailed identification of 1-phenylethyl acetate from clove (Syzygium aromaticum (L.) Merr. & L.M. Perry) buds. In addition, headspace solid-phase microextraction-gas chromatography/mass spectrometry (GC/MS) analysis revealed further occurrence of 1-phenylethyl acetate in cocoa pulp and grape hyacinth flowers. A total of 15.2 g of essential oil was recovered from 7.2 kg of clove buds by simultaneous distillation-extraction followed by vacuum distillation. The distillate obtained was fractionated by silica column chromatography, whereby a significant enrichment of 1-phenylethyl acetate was achieved. The fraction containing the target analyte was further purified by preparative high-performance liquid chromatography, resulting in a final purity of ∼93.0%, yielding a total of 1 to 2 mg of 1-phenylethyl acetate. Identification of the isolated compound was achieved by GC/MS, infrared spectroscopy, enantioselective GC, isotope ratio MS, and nuclear magnetic resonance spectroscopy. Enantioselective GC/MS analysis revealed an enantiomeric excess of 60% (1S)-(-)-1-phenylethyl acetate in the isolate. The δ13CV-PDB value of -32.5 ± 0.5‰ was in accordance with that of C3-plants and other constituents found in genuine clove extracts.

Prospective validation of prognostic and diagnostic syncope scores in the emergency department.

BACKGROUND: Various scores have been derived for the assessment of syncope patients in the emergency department (ED) but stay inconsistently validated. We aim to compare their performance to the one of a common, easy-to-use CHADS2 score. METHODS: We prospectively enrolled patients ≥ 40 years old presenting with syncope to the ED in a multicenter study. Early clinical judgment (ECJ) of the treating ED-physician regarding the probability of cardiac syncope was quantified. Two independent physicians adjudicated the final diagnosis after 1-year follow-up. Major cardiovascular events (MACE) and death were recorded during 2 years of follow-up. Nine scores were compared by their area under the receiver-operator characteristics curve (AUC) for death, MACE or the diagnosis of cardiac syncope. RESULTS: 1490 patients were available for score validation. The CHADS2-score presented a higher or equally high accuracy for death in the long- and short-term follow-up than other syncope-specific risk scores. This score also performed well for the prediction of MACE in the long- and short-term evaluation and stratified patients with accuracy comparative to OESIL, one of the best performing syncope-specific risk score. All scores performed poorly for diagnosing cardiac syncope when compared to the ECJ. CONCLUSIONS: The CHADS2-score performed comparably to more complicated syncope-specific risk scores in the prediction of death and MACE in ED syncope patients. While better tools incorporating biochemical and electrocardiographic markers are needed, this study suggests that the CHADS2-score is currently a good option to stratify risk in syncope patients in the ED. TRIAL REGISTRATION: NCT01548352.

Direct comparison of high-sensitivity-cardiac troponin I vs. T for the early diagnosis of acute myocardial infarction.

AIM: It is unknown whether cardiac troponin (cTn) I or cTnT is the preferred biomarker in the early diagnosis of acute myocardial infarction without ST segment elevation (NSTEMI). METHODS AND RESULTS: In a prospective multicentre study, we measured cTnI and cTnT using clinically available high-sensitivity assays (hs-cTnI Abbott and hs-cTnT Roche) and compared their diagnostic and prognostic accuracies in consecutive patients presenting to the emergency department with acute chest pain. The final diagnosis was adjudicated by two independent cardiologists using all information pertaining to the individual patient. The mean follow-up was 24 months. Among 2226 consecutive patients, 18% had an adjudicated final diagnosis of NSTEMI. Diagnostic accuracy at presentation as quantified by the area under the receiver-operating-characteristics curve (AUC) for NSTEMI was very high and similar for hs-cTnI [AUC: 0.93, 95% confidence interval (CI) 0.92-0.94] and hs-cTnT (0.94, 95% CI: 0.92-0.94) P = 0.62. In early presenters (<3 h since chest pain onset) hs-cTnI showed a higher diagnostic accuracy (AUC: 0.92, 95% CI: 0.89-0.94) when compared with hs-cTnT AUC (0.89, 95% CI: 0.86-0.91) (P = 0.019), while hs-cTnT was superior in late presenters [AUC hs-cTnT 0.96 (95% CI: 0.94-0.96)  vs. hs-cTnI 0.94 (95% CI: 0.93-0.95); P = 0.007]. The prognostic accuracy for all-cause mortality, quantified by AUC, was significantly higher for hs-cTnT (AUC: 0.80; 95% CI: 0.78-0.82) when compared with hs-cTnI (AUC: 0.75; 95% CI: 0.73-0.77; P < 0.001). CONCLUSION: Both hs-cTnI and hs-cTnT provided high diagnostic and prognostic accuracy. The direct comparison revealed small but potentially important differences that might help to further improve the clinical use of hs-cTn.

Utility of C-terminal proendothelin in the early diagnosis and risk stratification of patients with suspected acute myocardial infarction.

BACKGROUND: Endothelial dysfunction plays a major role in cardiovascular diseases, including acute myocardial infarction (AMI). However, its quantification has not been available as a clinical tool. METHODS: In a prospective international multicentre study, we analyzed the diagnostic and prognostic utility of endothelial dysfunction as quantified by C-terminal proendothelin-1 (CT-proET-1) in 658 consecutive patients presenting with suspected AMI. The final diagnosis was adjudicated by 2 independent cardiologists. Patients were followed long-term for mortality. RESULTS: The adjudicated final diagnosis was AMI in 145 patients (22%). The diagnostic performance of CT-proET-1 for AMI was moderate; its area under the receiver operating characteristic (ROC) curve amounted to 0.66 (95% confidence interval [CI], 0.61-0.72; P < 0.001). There was no significant increase in the AUC when CT-proET-1 was added to either cardiac troponin T (cTnT) or high-sensitivity cTnT (hs-cTnT). Seventy four percent of patients who died during the first 24 months (n = 50) were in the fourth quartile of the CT-proET-1 presentation value (>82 pmol/L). The prognostic accuracy of CT-proET-1 regarding mortality was tantamount to that of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and outperformed cTnT and hs-cTnT both in patients with AMI and in patients without acute coronary syndrome. CT-proET-1 at presentation yielded high prognostic accuracy that was similar to that of the Thrombolysis in Myocardial Infarction (TIMI) and Global Registry of Acute Coronary Events (GRACE) risk scores. The TIMI risk score could be significantly improved by adding CT-proET-1 (integrated discriminatory improvement [IDI] of 0.074 P = 0.004). CONCLUSIONS: Use of CT-proET-1 improves risk stratification of unselected patients with suspected AMI. CT-proET-1 did not provide additional diagnostic value.

Normal presenting levels of high-sensitivity troponin and myocardial infarction.

OBJECTIVE: To analyse whether levels of high-sensitivity cardiac troponin (hs-cTn) below their respective 99th percentile can be used as a single parameter to rule out acute myocardial infarction (AMI) at presentation. DESIGN: Prospective, multicentre study. MAIN OUTCOME MEASURES: We measured hs-cTn using four different methods (hs-cTnT Roche, hs-cTnI Siemens, hs-cTnI Beckman Coulter and hs-cTnI Abbott) in consecutive patients presenting to the emergency department with acute chest pain. Two independent cardiologists adjudicated the final diagnosis. Patients were followed for death or AMI during a mean period of 24 months. RESULTS: Among 2072 consecutive patients with hs-cTnT measurements available, 21.4% had an adjudicated diagnosis of AMI (sensitivity 89.6%, 95% CI 86.4% to 92.3%, negative predictive value (NPV): 96.5%, 95% CI 95.4% to 97.4%). Among 1180 consecutive patients with hs-cTnI Siemens measurements available, 20.0% had AMI (sensitivity 94.1%, 95% CI 90.3% to 96.7%, NPV: 98.0%, 95% CI: 96.6% to 98.9%). Among 1151 consecutive patients with hs-cTnI Beckman Coulter measurements available, 19.7% had AMI (sensitivity 92.1%, 95% CI 87.8% to 95.2%, NPV: 97.5%, 95% CI 96.0% to 98.5%). Among 1567 consecutive patients with hs-cTnI Abbott measurements available, 20.0% had AMI (sensitivity 77.2%, 95% CI 72.1% to 81.7%, NPV: 94.3%, 95% CI 92.8% to 95.5%). CONCLUSIONS: Normal hs-cTn levels at presentation should not be used as a single parameter to rule out AMI as 6%-23% of adjudicated AMI cases had normal levels of hs-cTn levels at presentation. Our data highlight the lack of standardisation among hs-cTnI assays resulting in substantial differences in sensitivity and NPV at the 99th percentile.

Expression and function of the empty spiracles gene in olfactory sense organ development of Drosophila melanogaster.

In Drosophila, the cephalic gap gene empty spiracles plays key roles in embryonic patterning of the peripheral and central nervous system. During postembryonic development, it is involved in the development of central olfactory circuitry in the antennal lobe of the adult. However, its possible role in the postembryonic development of peripheral olfactory sense organs has not been investigated. Here, we show that empty spiracles acts in a subset of precursors that generate the olfactory sense organs of the adult antenna. All empty spiracles-expressing precursor cells co-express the proneural gene amos and the early patterning gene lozenge. Moreover, the expression of empty spiracles in these precursor cells is dependent on both amos and lozenge. Functional analysis reveals two distinct roles of empty spiracles in the development of olfactory sense organs. Genetic interaction studies in a lozenge-sensitized background uncover a requirement of empty spiracles in the formation of trichoid and basiconic olfactory sensilla. MARCM-based clonal mutant analysis reveals an additional role during axonal targeting of olfactory sensory neurons to glomeruli within the antennal lobe. Our findings on empty spiracles action in olfactory sense organ development complement previous studies that demonstrate its requirement in olfactory interneurons and, taken together with studies on the murine homologs of empty spiracles, suggest that conserved molecular genetic programs might be responsible for the formation of both peripheral and central olfactory circuitry in insects and mammals.

Identification of bisprenylated benzoic acid derivatives from yerba santa (Eriodictyon ssp.) using sensory-guided fractionation.

Due to certain off-flavor problems and lacking bitter masking effects with Yerba Santa (Eriodictyon angustifolium and E. californicum) extracts, which are also described as bitter, herbal, medicinal, phenolic, or astringent, methanolic extracts were fractionated and evaluated for their taste properties using a high temperature liquid chromatography (HTLC)-based approach. The taste-guided fractionation led to the identification of a series of novel bisprenylated benzoic acids (erionic acids A (1), B (2), C (3), D (4), E (5), and F (6) and eriolic acids A (7), B (8), C (9), and D (10), respectively), along with the known flavonoids eriodictyol, homoeriodictyol, hesperetin, and chrysoeriol. The new compounds were isolated in larger amounts for characterization from Narrow Leaf Yerba Santa (E. angustifolium) and California Yerba Santa (E. californicum), respectively, using fast centrifugal partition chromatography (FCPC) and HTLC. The structures were elucidated using one and two-dimensional NMR spectroscopy and high resolution mass spectrometry (HR-MS). For E. californicum, data regarding seasonal and climatic variation of the eriolic acid contents and of the flavonoids were collected. The flavor properties of some of the isolated new compounds were evaluated; they showed strong off-flavor characteristics, such as bitter, astringent, phenolic, or woody, and may contribute to the sensory effects observed for crude Yerba Santa extracts. Erionic acid C (3) was not only able to increase the absolute bitterness but also to extinguish the bitter masking effect of homoeriodictyol in a caffeine solution.

Coral emx-Am can substitute for Drosophila empty spiracles function in head, but not brain development.

The ems/Emx genes encode homeodomain transcription factors that have conserved actions in anterior embryonic patterning in bilaterian animals ranging from insects to mammals. Recently, genes of the ems/Emx family have been identified in cnidarians raising the possibility that some of their developmental functions might be conserved throughout the Eumetazoa. To determine to what extent functions of a cnidarian ems/Emx protein have been retained across phyla, we carried out cross-phylum rescue expression experiments in which the coral Acropora emx-Am gene was misexpressed in Drosophila ems mutants. Our findings demonstrate that coral emx-Am can substitute for fly ems in embryonic head development and rescue the open head defect and the loss of segmental engrailed expression domains in Drosophila ems mutants. In contrast, the coral emx-Am gene can not substitute for fly ems in embryonic brain development. Even when a hexapeptide motif of the type present in the Drosophila ems gene is inserted into the coral emx-Am gene, rescue of the developmental brain defects in fly ems mutants fails. These findings have implications for understanding the evolutionary origins of head versus brain patterning mechanisms.

Liquid chromatography/mass spectrometry and liquid chromatography/nuclear magnetic resonance as complementary analytical techniques for unambiguous identification of polymethoxylated flavones in residues from molecular distillation of orange peel oils (Citrus sinensis).

Liquid chromatography/mass spectrometry and liquid chromatography/nuclear magnetic resonance techniques with ultraviolet/diode array detection were used as complementary analytical tools for the reliable identification of polymethoxylated flavones in residues from molecular distillation of cold-pressed peel oils of Citrus sinensis. After development of a liquid chromatographic separation procedure, the presence of several polymethoxy flavones such as sinensetin, nobiletin, tangeretin, quercetogetin, heptamethoxyflavone, and other derivatives was unambiguously confirmed. In addition, proceranone, an acetylated tetranortriterpenoid with limonoid structure, was identified for the first time in citrus.