Floral flavonoids and pH in Dendrobium orchid species and hybrids

Anthocyanidins were identified in 28 Dendrobium species and hybrids selected for analysis based on colour and suitability in cut flower breeding. Flowers designated pink, red, maroon, orange, bronze, and brown in the trade were placed in RHS colour groups red-purple, purple-violet, violet on yellow, greyed-purple on yellow or yellow-orange, and brown. This colour range contained anthocyanins based on cyanidin, with peonidin occurring as a minor pigment. The colours of three blue genotypes, D. gouldii K280-6, D. biggibum ‘blue’, and D. Kultana ‘blue’, were light violet to purple by RHS standards and contained anthocyanins based on cyanidin. Peach-coloured flowers were classified as red or red-purple and included pelargonidin glycosides. Anthocyanin concentrations ranged from 0.13 to 0.18 μmoles/g FW in light lavender and peach, and up to 3.66 μmoles/g FW in brown. Combined cellular and vacuolar pH ranged narrowly from 4.67 to 5.09 among white, peach, lavender, and brown lines. Predominant copigments were flavonol glycosides based on kaempferol, quercetin, myricetin, and methylated derivatives. Flavonol aglycones and glycosylation sites differed little among two colour forms of D. gouldii and two D. Jaquelyn Thomas hybrids. Accumulation of quercetin, myricetin, and cyanidin indicated flavonoid 3' and 3',5' hydroxylation activities in several Dendrobium. Additional accumulation of isorhamnetin, syringetin, and peonidin indicated active flavonoid 3'- and 3',5'- O-methyltransferase enzymes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cinchonicine-derived alkaloids from the bark of the Peruvian Ladenbergia oblongifolia.

The isolation of cinchonicine-derived alkaloids epicinchonicinol (1), cinchonidicinol (2) and a mixture of dihydrocinchonicinol and dihydrocinchonidicinol (3) from the dried bark of Ladenbergia oblongifolia, is reported along with (1)H and (13)C-NMR data.     

Acrylamide in foods: occurrence,sources, and modeling

Acrylamide in food products-chiefly in commercially available potato chips, potato fries, cereals, and bread-was determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Samples were homogenized with water/dichloromethane, centrifuged, and filtered through a 5 kDa filter. The filtrate was cleaned up on mixed mode, anion and cation exchange (Oasis MAX and MCX) and carbon (Envirocarb) cartridges. Analysis was done by isotope dilution ([D(3)]- or [(13)C(3)]acrylamide) electrospray LC-MS/MS using a 2 x 150 mm (or 2 x 100 mm) Thermo HyperCarb column eluted with 1 mM ammonium formate in 15% (or 10% for the 2 x 100 mm column) methanol. Thirty samples of foods were analyzed. Concentrations of acrylamide varied from 14 ng/g (bread) to 3700 ng/g (potato chips). Acrylamide was formed during model reactions involving heating of mixtures of amino acids and glucose in ratios similar to those found in potatoes. In model reactions between amino acids and glucose, asparagine was found to be the main precursor of acrylamide. Thus, in the reaction between nitrogen-15 (amido)-labeled asparagine and glucose, corresponding (15)N-labeled acrylamide was formed. The yield of the model reaction is approximately 0.1%.     

Localization of amyloid beta protein messenger RNA in brains from patients with Alzheimer's disease

The distribution of cells containing messenger RNA that encodes amyloid beta protein was determined in hippocampi and in various cortical regions from cynomolgus monkeys, normal humans, and patients with Alzheimer's disease by in situ hybridization. Both 35S-labeled RNA antisense and sense probes to amyloid beta protein messenger RNA were used to ensure specific hybridization. Messenger RNA for amyloid beta protein was expressed in a subset of neurons in the prefrontal cortex from monkeys, normal humans, and patients with Alzheimer's disease. This messenger RNA was also present in the neurons of all the hippocampal fields from monkeys, normal humans and, although to a lesser extent in cornu ammonis 1, patients with Alzheimer's disease. The distribution of amyloid beta protein messenger RNA was similar to that of the neurofibrillary tangles of Alzheimer's disease in some regions, but the messenger RNA was also expressed in other neurons that are not usually involved in the pathology of Alzheimer's disease.     

A hazard quotient approach for assessing the risk to non-target arthropods from

The EU Plant Protection Product Directive 91/414/EEC recommends the EPPO/CoE Arthropod Natural Enemies Risk Assessment Scheme for guidance on how to conduct risk assessments for terrestrial non-target arthropods. This scheme is currently in the process of being revised by EPPO/ CoE. A major change will be the recommendation for the generation and use of ’Dose Response’ toxicity data instead of limit test data. In addition, the revised EPPO/CoE Non-target Arthropods Risk Assessment Scheme will replace the current arbitrary 30% threshold trigger value applied to limit test data, with a Hazard Quotient (HQ; = Ratio Application Rate/LC50 on Glass)), comparable to the successful approach adopted in the EPPO/CoE ’Honeybee Risk Assessment Scheme’. However, in order for this new approach to be implemented under 91/414/EEC, an appropriate regulatory HQ trigger value needs to be derived. Such an HQ trigger value has been established by calculating HQ values for the 2 recommended sensitive indicator species (T pyri andAphidius) for a wide range of products and validating opposite robust semi-field/field data. This validation indicated that an HQ trigger value of ≥ 12 forT pyri and ≥ 8 forAphidius spp., should be used to trigger higher-tier risk assessment and/or higher-tier testing for non-target arthropods. As these trigger values were validated with realistic semi-field/ field data they apply for both lethal and sub-lethal effects as well as single and multiple application scenarios. Due to the worst case assumptions used in this HQ validation analysis, no further uncertainty factors need to be applied for in-crop risk assessment. Whilst a small amount of uncertainty exists regarding the comparative sensitivity ofT pyri andAphidius spp. for off-crop non-target arthropod guilds of arthropods, this is balanced by the fact that the off-crop exposure assessment used in the HQ derivation, is at least an order of magnitude higher than that realistically likely in the field. This HQ approach and trigger value is an appropriate and conservative tool for tier 1 risk assessment, which should reduce the number of false positive results leading to unnecessary higher-tier testing.     

Modelling the transport of lobster (Homarus americanus) larvae and postlarvae in the Gulf of Maine

We used a coupled physical–biological model to examine potential distances between hatching and settlement locations for lobsters in the Gulf of Maine. The physical model is based on a finite-element mesh and climatological averages of the seasonally evolving temperature and density fields. Larval trajectories from coastal and offshore hatching sites (21–224 m deep) were calculated for early, middle and late-season hatching by coupling temperature-dependent development rates and depth (the biological model) to the circulation. Model results showed large spatial differences in larval development times (from 18 to 38 days) and distances transported (19–280 km) for the early hatch. Development time and transport decreased markedly by mid-season at most sites, but strong spatial differences persisted. The eastern Maine coast appears to experience stronger removal and less resupply of larvae than other regions, consistent with observed lower recruitment. Inverse solutions of the model for larvae arriving in mid-coastal Maine indicate that they originate from a broad section of the eastern coast 'upstream', with those nearest the shoreline generally travelling the shortest distances. The postlarval stage is neustonic (living near the surface), and a simple inverse model demonstrates that a diurnal coastal sea breeze can contribute substantially to inshore movement during this final planktonic stage. Thus, offshore reproduction may be linked to inshore recruitment.     

绵羊的疫苗接种

兽医疾病调查资料的统计学分析结果表明 ,在过去 1 0年 ,绵羊最常见的死因 ,按死亡率从高到低排列 ,依次是 :绵羊地方流行性流产 (EAE)、弓浆虫病、巴氏杆菌病、梭状芽胞杆菌病、流行性魏氏梭菌病和羔羊痢疾。通过疫苗接种 ,所有这些疫病均可得到预防和控制。1　疫苗控制的绵羊疫病在英国 ,绵羊与其它家畜不同 ,可利用疫苗防止细菌、病毒和原生动物的感染。除上述疫病外 ,临床上常见的传染性脓疱皮炎和腐蹄病 ,尽管在兽医疾病调查资料的统计学分析中因其死亡率低未专门列出 ,但也往往造成大批绵羊发病 ,通过接种疫苗 ,虽不能根除 ,却可得…     

Morphoagronomic and biochemical variation in an Argentinean landrace of wheat

A sample of an Argentinean landrace of wheat showed considerable variation in most of the evaluated morphological and agronomic characters. However, analyses with high molecular glutenins and two isozyme systems, known to be highly polymorphic among current cultivars, revealed very little or no variation, respectively. The large difference in the observed variation between morphoagronomic and biochemical characters is discussed.