Nonvolatiles of commercial lime and grapefruit oils separated by high-speed countercurrent chromatography     

Feger W  Brandauer H  Gabris P  Ziegler H 《Journal of agricultural and food chemistry》2006,54(6):2242-2252

The nonvolatile fractions of cold-pressed peel oils of Key and Persian lime as well as grapefruit were separated by high-speed countercurrent chromatography (HS-CCC). In addition to the isolation of the main coumarins, psoralens and polymethoxyflavones, a number of minor constituents were enriched and successfully characterized by GC-MS and HPLC-UV. 5,7,8-Trimethoxycoumarin and the cyclical acetals of oxypeucedanin hydrate with citral were determined as new nonvolatile trace constituents of lime oils and confirmed by NMR spectroscopy. The citral oxypeucedaninyl acetals were found particularly in Key lime oil type A, which as a result of the juice-oil contact, is exposed to acidic conditions during industrial processing. Some of the confirmed minor constituents, such as pabulenol, isooxypeucedanin, and oxypeucedanin methanolate in lime as well as auraptenol in grapefruit, may have been generated by hydrolysis-sensitive precursors during CCC separation or their respective industrial processing techniques.  相似文献   

ATP release guides neutrophil chemotaxis via P2Y2 and A3 receptors     

Chen Y  Corriden R  Inoue Y  Yip L  Hashiguchi N  Zinkernagel A  Nizet V  Insel PA  Junger WG 《Science (New York, N.Y.)》2006,314(5806):1792-1795

Cells must amplify external signals to orient and migrate in chemotactic gradient fields. We find that human neutrophils release adenosine triphosphate (ATP) from the leading edge of the cell surface to amplify chemotactic signals and direct cell orientation by feedback through P2Y2 nucleotide receptors. Neutrophils rapidly hydrolyze released ATP to adenosine that then acts via A3-type adenosine receptors, which are recruited to the leading edge, to promote cell migration. Thus, ATP release and autocrine feedback through P2Y2 and A3 receptors provide signal amplification, controlling gradient sensing and migration of neutrophils.  相似文献   

Paleoecology. Life's complexity cast in stone     

Kiessling W 《Science (New York, N.Y.)》2006,314(5803):1254-1255

  相似文献   

BKCa-Cav channel complexes mediate rapid and localized Ca2+-activated K+ signaling     

Berkefeld H  Sailer CA  Bildl W  Rohde V  Thumfart JO  Eble S  Klugbauer N  Reisinger E  Bischofberger J  Oliver D  Knaus HG  Schulte U  Fakler B 《Science (New York, N.Y.)》2006,314(5799):615-620

Large-conductance calcium- and voltage-activated potassium channels (BKCa) are dually activated by membrane depolarization and elevation of cytosolic calcium ions (Ca2+). Under normal cellular conditions, BKCa channel activation requires Ca2+ concentrations that typically occur in close proximity to Ca2+ sources. We show that BKCa channels affinity-purified from rat brain are assembled into macromolecular complexes with the voltage-gated calcium channels Cav1.2 (L-type), Cav2.1 (P/Q-type), and Cav2.2 (N-type). Heterologously expressed BKCa-Cav complexes reconstitute a functional "Ca2+ nanodomain" where Ca2+ influx through the Cav channel activates BKCa in the physiological voltage range with submillisecond kinetics. Complex formation with distinct Cav channels enables BKCa-mediated membrane hyperpolarization that controls neuronal firing pattern and release of hormones and transmitters in the central nervous system.  相似文献   

Biogenic potassium salt particles as seeds for secondary organic aerosol in the Amazon     

C Pöhlker  KT Wiedemann  B Sinha  M Shiraiwa  SS Gunthe  M Smith  H Su  P Artaxo  Q Chen  Y Cheng  W Elbert  MK Gilles  AL Kilcoyne  RC Moffet  M Weigand  ST Martin  U Pöschl  MO Andreae 《Science (New York, N.Y.)》2012,337(6098):1075-1078

The fine particles serving as cloud condensation nuclei in pristine Amazonian rainforest air consist mostly of secondary organic aerosol. Their origin is enigmatic, however, because new particle formation in the atmosphere is not observed. Here, we show that the growth of organic aerosol particles can be initiated by potassium-salt-rich particles emitted by biota in the rainforest. These particles act as seeds for the condensation of low- or semi-volatile organic compounds from the atmospheric gas phase or multiphase oxidation of isoprene and terpenes. Our findings suggest that the primary emission of biogenic salt particles directly influences the number concentration of cloud condensation nuclei and affects the microphysics of cloud formation and precipitation over the rainforest.  相似文献   

Cyanophora paradoxa genome elucidates origin of photosynthesis in algae and plants     

Price DC  Chan CX  Yoon HS  Yang EC  Qiu H  Weber AP  Schwacke R  Gross J  Blouin NA  Lane C  Reyes-Prieto A  Durnford DG  Neilson JA  Lang BF  Burger G  Steiner JM  Löffelhardt W  Meuser JE  Posewitz MC  Ball S  Arias MC  Henrissat B  Coutinho PM  Rensing SA  Symeonidi A  Doddapaneni H  Green BR  Rajah VD  Boore J  Bhattacharya D 《Science (New York, N.Y.)》2012,335(6070):843-847

  相似文献   

Compartmentalized control of skin immunity by resident commensals     

S Naik  N Bouladoux  C Wilhelm  MJ Molloy  R Salcedo  W Kastenmuller  C Deming  M Quinones  L Koo  S Conlan  S Spencer  JA Hall  A Dzutsev  H Kong  DJ Campbell  G Trinchieri  JA Segre  Y Belkaid 《Science (New York, N.Y.)》2012,337(6098):1115-1119

Intestinal commensal bacteria induce protective and regulatory responses that maintain host-microbial mutualism. However, the contribution of tissue-resident commensals to immunity and inflammation at other barrier sites has not been addressed. We found that in mice, the skin microbiota have an autonomous role in controlling the local inflammatory milieu and tuning resident T lymphocyte function. Protective immunity to a cutaneous pathogen was found to be critically dependent on the skin microbiota but not the gut microbiota. Furthermore, skin commensals tuned the function of local T cells in a manner dependent on signaling downstream of the interleukin-1 receptor. These findings underscore the importance of the microbiota as a distinctive feature of tissue compartmentalization, and provide insight into mechanisms of immune system regulation by resident commensal niches in health and disease.  相似文献   

Comment on "Nonreciprocal light propagation in a silicon photonic circuit"     

Fan S  Baets R  Petrov A  Yu Z  Joannopoulos JD  Freude W  Melloni A  Popović M  Vanwolleghem M  Jalas D  Eich M  Krause M  Renner H  Brinkmeyer E  Doerr CR 《Science (New York, N.Y.)》2012,335(6064):38; author reply 38

We show that the structure demonstrated by Feng et al. (Reports, 5 August 2011, p. 729) cannot enable optical isolation because it possesses a symmetric scattering matrix. Moreover, one cannot construct an optical isolator by incorporating this structure into any system as long as the system is linear and time-independent and is described by materials with a scalar dielectric function.  相似文献   

Seizure activity in dogs is associated with enhanced TIMP-2 expression of microglia     

Stein VM  Genini S  Puff C  Baumgärtner W  Tipold A 《Veterinary immunology and immunopathology》2012,146(2):101-105

In the pathogenesis of epilepsy aberrant synaptic plasticity plays an important role. Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) are responsible for nervous tissue remodelling resulting in synaptic plasticity in the central nervous system (CNS) and might therefore be crucially involved in epileptogenesis. To assess the potential pathogenetic role of microglial MMPs and TIMPs in seizure induction, twenty-four dogs suffering from different intracranial diseases with and without seizure activity were comparatively examined. Microglial cells were isolated by density gradient centrifugation and their expression profiles of MMP-2, MMP-9, MMP-12, MMP-13, MMP-14, TIMP-1, TIMP-2, and RECK (reversion-inducing cysteine-rich protein with Kazal motifs) were examined via quantitative real-time PCR (qPCR). Interestingly, a significant up-regulation of TIMP-2 expression was found for the first time in dogs suffering from seizures. In conclusion, microglial TIMP expression might be involved in seizure generation.  相似文献   

Establishment of diagnostic criteria for feline nonflea-induced hypersensitivity dermatitis     

Favrot C  Steffan J  Seewald W  Hobi S  Linek M  Marignac G  Olivry T  Beco L  Nett C  Fontaine J  Roosje P  Bergvall K  Belova S  Koebrich S  Pin D  Kovalik M  Meury S  Wilhelm S 《Veterinary dermatology》2012,23(1):45-50, e11

Hypersensitivity dermatitides (HD) are commonly seen in cats, and they are usually caused by environmental, food and/or flea allergens. Affected cats normally present with one of the following clinical reaction patterns: head and neck excoriations, usually symmetrical self-induced alopecia, eosinophilic skin lesions or miliary dermatitis. Importantly, none of these clinical presentations is considered to be pathognomonic for HD skin diseases, and the diagnosis of HD is usually based on the exclusion of other pruritic diseases and on a positive response to therapy. The objectives of this study were to propose sets of criteria for the diagnosis of nonflea-induced HD (NFHD). We recruited 501 cats with pruritus and skin lesions and compared clinical parameters between cats with NFHD (encompassing those with nonflea, nonfood HD and those with food HD), flea HD and other pruritic conditions. Using simulated annealing techniques, we established two sets of proposed criteria for the following two different clinical situations: (i) the diagnosis of NFHD in a population of pruritic cats; and (ii) the diagnosis of NFHD after exclusion of cats with flea HD. These criteria sets were associated with good sensitivity and specificity and may be useful for homogeneity of enrolment in clinical trials and to evaluate the probability of diagnosis of NFHD in clinical practice. Finally, these criteria were not useful to differentiate cats with NFHD from those with food HD.  相似文献