Competencies: a cure for pre-med curriculum     

Anderson WA  Amasino RM  Ares M  Banerjee U  Bartel B  Corces VG  Drennan CL  Elgin SC  Epstein IR  Fanning E  Guillette LJ  Handelsman J  Hatfull GF  Hoy RR  Kelley D  Leinwand LA  Losick R  Lu Y  Lynn DG  Neuhauser C  O'Dowd DK  Olivera T  Pevzner P  Richards-Kortum RR  Rine J  Sah RL  Strobel SA  Walker GC  Walt DR  Warner IM  Wessler S  Willard HF  Zare RN 《Science (New York, N.Y.)》2011,334(6057):760-761

  相似文献   

Vitamin D and sterol composition of 10 types of mushrooms from retail suppliers in the United States     

Phillips KM  Ruggio DM  Horst RL  Minor B  Simon RR  Feeney MJ  Byrdwell WC  Haytowitz DB 《Journal of agricultural and food chemistry》2011,59(14):7841-7853

Vitamin D(2) (ergocalciferol) and sterols were analyzed in mushrooms sampled nationwide in the United States to update the USDA Nutrient Database for Standard Reference. Vitamin D(2) was assayed using HPLC with [(3)H]-vitamin D(3) internal standard and sterols by GC-FID mass spectrometric (MS) confirmation. Vitamin D(2) was low (0.1-0.3 μg/100 g) in Agaricus bisporus (white button, crimini, portabella) and enoki, moderate in shiitake and oyster (0.4-0.7 μg/100 g), and high in morel, chanterelle, maitake (5.2-28.1 μg/100 g) and UV-treated portabella (3.4-20.9 μg/100 g), with significant variability among composites for some types. Ergosterol (mg/100 g) was highest in maitake and shiitake (79.2, 84.9) and lowest in morel and enoki (26.3, 35.5); the range was <10 mg/100 g among white button composites but 12-50 mg/100 g among samples of other types. All mushrooms contained ergosta-5,7-dienol (22,23-dihydroergosterol) (3.53-18.0 mg/100 g) and (except morel) ergosta-7-enol. Only morel contained brassicasterol (28.6 mg/100 g) and campesterol (1.23-4.54 mg/100 g) and no ergosta-7,22-dienol. MS was critical in distinguishing campesterol from ergosta-7,22-dienol.  相似文献   

Vitamin D mushrooms: comparison of the composition of button mushrooms (Agaricus bisporus) treated postharvest with UVB light or sunlight     

Simon RR  Phillips KM  Horst RL  Munro IC 《Journal of agricultural and food chemistry》2011,59(16):8724-8732

This study compared the compositional changes in mushrooms exposed to sunlight with those occurring after commercial ultraviolet (UV) light processing. Button mushrooms (75 kg) were processed in the presence or absence of UVB light; a third group was exposed to direct sunlight. Mushroom composition was evaluated using chemical analyses. Vitamin D concentrations were 5, 410, and 374 μg/100 g (dw) in control, UVB, and sunlight groups, respectively. On a dry weight basis, no significant changes in vitamin C, folate, vitamins B(6), vitamin B(5), riboflavin, niacin, amino acids, fatty acids, ergosterol, or agaritine were observed following UVB processing. Sunlight exposure resulted in a 26% loss of riboflavin, evidence of folate oxidation, and unexplained increases in ergosterol (9.5%). It was concluded that compositional effects of UVB light are limited to changes in vitamin D and show no detrimental changes relative to natural sunlight exposure and, therefore, provide important information relevant to the suitability and safety of UVB light technology for vitamin D enhanced mushrooms.  相似文献   

Assessment of a point‐of‐care cardiac troponin I test to differentiate cardiac from noncardiac causes of respiratory distress in dogs     

Edward E. Payne DVM  Brian K. Roberts DVM  DACVECC  Nick Schroeder DVM  DACVIM  Ronald L. Burk DVM  MS  DACVR  Thomas Schermerhorn VMD  DACVIM 《Journal of Veterinary Emergency and Critical Care》2011,21(3):217-225

Objectives – To (1) determine a reference interval for cardiac troponin I (cTnI) using a point‐of‐care device in normal dogs and compare the results with those published by the manufacturer and (2) determine if cTnI differs among dogs with cardiogenic and noncardiogenic respiratory distress. Design – Prospective observational study. Setting – Emergency and referral veterinary hospital. Animals – Twenty‐six clinically normal dogs and 67 dogs in respiratory distress. Interventions – All dogs underwent whole blood sampling for cTnI concentrations. Measurements and Results – Normal dogs had a median cTnI concentration of 0.03 ng/mL (range 0–0.11 ng/mL). Thirty‐six dogs were diagnosed with noncardiogenic respiratory distress with a median cTnI concentration of 0.14 ng/mL (range 0.01–4.31 ng/mL). Thirty‐one dogs were diagnosed with cardiogenic respiratory distress with a median cTnI concentration of 1.74 ng/mL (range 0.05–17.1 ng/mL). A significant difference between cTnI concentrations in normal dogs and dogs with noncardiogenic respiratory distress was not detected. Significant differences in cTnI concentrations were found between normals versus cardiogenic and cardiogenic versus noncardiogenic respiratory distress groups. Significant differences in cTnI concentrations were identified in >10 when compared with the <5 and the 5–10 years of age groups. Receiver operating curve analysis identified cTnI concentrations >1.5 ng/mL as the optimal “cut‐off point” having a sensitivity of 78% and specificity of 51.5%. The area under the receiver operating curve was 0.72. Overall test accuracy was 65%. Conclusions – cTnI concentrations were significantly increased in dogs with cardiogenic respiratory distress versus dogs with noncardiogenic respiratory distress and normal dogs. A significant difference between normal dogs and dogs with noncardiogenic causes of respiratory distress was detected. Although highly sensitive when cTnI concentrations exceed 1.5 ng/mL, the test has low specificity. Assessment of cTnI by the methodology used cannot be recommended as the sole diagnostic modality for evaluating the cause of respiratory distress in dogs.  相似文献   

Anthocyanin and proanthocyanidin content in selected white and red wines. Oxygen radical absorbance capacity comparison with nontraditional wines obtained from highbush blueberry     

Sánchez-Moreno C  Cao G  Ou B  Prior RL 《Journal of agricultural and food chemistry》2003,51(17):4889-4896

Antioxidant capacity, as measured by oxygen radical absorbance capacity (ORAC(PE)), total phenolic, total and individual anthocyanins, and proanthocyanidin fraction contents were evaluated in red and white wines from grapes. A comparison in terms of antioxidant capacity is made with nontraditional wines made from highbush blueberry. Blueberries are among fruits that are best recognized for their potential health benefits. In red wines, total oligomeric proanthocyanidin content, including catechins, was substantially higher (177.18 +/- 96.06 mg/L) than that in white wines (8.75 +/- 4.53 mg/L). A relative high correlation in red wines was found between ORAC(PE) values and malvidin compounds (r = 0.75, P < 0.10), and proanthocyanidins (r = 0.87, P < 0.05). In white wines, a significant correlation was found between the trimeric proanthocyanidin fraction and peroxyl radical scavenging values (r = 0.86, P < 0.10). A moderate drink (1 drink per day, about 140 mL) of red wine, or white wine, or wine made from highbush blueberry corresponds to an intake of 2.04 +/- 0.81 mmol of TE, 0.47 +/- 0.15 mmol of TE, and 2.42 +/- 0.88 mmol of TE of ORAC(PE)/day, respectively.  相似文献   

Screening of foods containing proanthocyanidins and their structural characterization using LC-MS/MS and thiolytic degradation     

Gu L  Kelm MA  Hammerstone JF  Beecher G  Holden J  Haytowitz D  Prior RL 《Journal of agricultural and food chemistry》2003,51(25):7513-7521

A normal-phase HPLC-MS/MS method was applied to screen for proanthocyanidins in 88 different kinds of foods. Thirty-nine foods were found to contain proanthocyanidins. These foods include 19 kinds of fruits, eight cereals/beans, seven nuts, two beverages, two spices, and one vegetable. Twenty-five kinds of foods were found to contain both oligomeric (DP 10), and the other 14 foods contained only oligomers. Procyanidins with B-type linkages were detected as the only components in 21 foods and also as principal components in the others. Propelargonidins were identified in pinto bean, raspberry, strawberry, and almond, etc. Plum, avocado, peanut, curry, and cinnamon were identified as potential sources of A-type proanthocyanidins in addition to cranberry. Thiolytic degradation and MS/MS analyses indicated that the A-type linkages are present as a terminal unit in plum or between the extension units in curry, cinnamon, and avocado, whereas A-type linkages exist at both positions in cranberry and peanut.  相似文献   

Vegetation redistribution: A possible biosphere source of CO2 during climatic change     

Ronald P. Neilson 《Water, air, and soil pollution》1993,70(1-4):659-673

A new biogeographic model, MAPSS, predicts changes in vegetation leaf area index (LAI), site water balance and run off, as well as changes in Biome boundaries. Potential scenarios of equilibrium vegetation redistribution under 2 × CO₂ climate from five different General Circulation Models (GCMs) are presented. In general, large spatial shifts in temperate and boreal vegetation are predicted under the different scenarios; while, tropical vegetation boundaries are predicted (with one exception) to experience minor distribution contractions. Maps of predicted changes in forest LAI imply drought-induced losses of biomass over most forested regions, even in the tropics. Regional patterns of forest decline and dieback are surprisingly consistent among the five GCM scenarios, given the general lack of consistency in predicted changes in regional precipitation patterns. Two factors contribute to the consistency among the GCMs of the regional ecological impacts of climatic change: 1) regional, temperature-induced increases in potential evapotranspiration (PET) tend to more than offset regional increases in precipitation; and, 2) the unchanging background interplay between the general circulation and the continental margins and mountain ranges produces a fairly stable pattern of regionally specific sensitivity to climatic change. Two areas exhibiting among the greatest sensitivity to drought-induced forest decline are eastern North America and eastern Europe to western Russia. Drought-induced vegetation decline (losses of LAI), predicted under all GCM scenarios, will release CO₂ to the atmosphere; while, expansion of forests at high latitudes will sequester CO₂. The imbalance in these two rate processes could produce a large, transient pulse of CO₂ to the atmosphere.  相似文献   

Rock phosphate-P enhances biomass and nitrogen accumulation by legumes in upland crop production systems in humid West Africa     

Eklou A. Somado  Kanwar L. Sahrawat  Ronald F. Kuehne 《Biology and Fertility of Soils》2006,43(1):124-130

Experiments were conducted during 1996–1998 in screen house and in the field in the humid forest zone of Côte d’Ivoire, to evaluate the effects of phosphorus (P) from phosphate rock (PR) on the performance of the root nodulating legume Crotalaria micans grown for 8 weeks. The experimental soils were acid Ultisols with <4 mg/kg extractable Bray-1 P. Tilemsi PR from Mali and triple superphosphate (TSP) were applied at 60 kg P ha^?1 (screen house) and 90 kg P ha^?1 (field) to the legume. Legume N-fixed (BNF) was estimated by the ¹⁵N-isotope dilution and δ ¹⁵N natural abundance methods, using Cassia obtusifolia L. as a non-fixing legume reference plant. Without P supply, and under the field conditions, C. micans produced less than 1 tonne of biomass and accumulated 29 kg N/ha. The application of PR-P enhanced legume N by about fourfold over the unfertilised control. There was no significant difference between the effects of TSP and PR. Phosphorus application mainly affected the total amount of N accumulated rather than the percentage derived from the atmosphere (%N dfa) per se. Furthermore, the cumulative effects of PR-P on the performance of C. micans greatly improved with time in the screen house. This study confirms that Tilemsi PR is an agronomically effective source of P for short-duration legume green manure (GM) even in the first year of its application to acid P-deficient soils in the West African humid zone.  相似文献   

Recent trends in the acid-base status of surface waters in Maine,USA     

Jeffrey S. Kahl  Terry A. Haines  Stephen A. Norton  Ronald B. Davis 《Water, air, and soil pollution》1993,67(3-4):281-300

Data from the EPA Long Term Monitoring Program lakes at the Tunk Mountain Watershed, Maine, indicate that decreases of ≤1 Μeq L^?1 yr^?1 in SO₄, and increases of ≤2 Μeq L^?1 yr^?1 in ANC occurred in the 1980s. The sum of base cations also increased. These changes in aquatic chemistry were coincident with decreased concentrations of all solutes in precipitation during the 1980s. Other data on lakes and streams in Maine collected between the 1930s and 1990 generally confirm these trends and further indicate that larger increases in ANC may have occurred in some lowland lakes since 1940. Paleolimnologic studies indicate that decreases of 0.1 to 0.5 pH units occurred in a few small mountain lakes during the past 20 to 70 yr. However, ongoing acidification of lakes is indicated based on available data. Only lakes that were already at least marginally acidic (pH ≤5.8, ANC approximately 0) appear to have acidified.  相似文献   

Methyl esterification divergently affects the degradability of pectic uronosyls in nonlignified and lignified maize cell walls     

Grabber JH  Hatfield RD 《Journal of agricultural and food chemistry》2005,53(5):1546-1549

Nonlignified cell walls from Zea mays (L.) cell suspensions were incubated with and without pectin methylesterase (PME) and a portion were artificially lignified to assess how methyl esters influence the release of pectic uronosyls and total sugars from cell walls by fungal enzymes. Treatment with PME reduced uronosyl concentrations from 97 to 92 mg/g, reduced uronosyl methylation from 57% to 21%, and increased Klason lignin concentrations in artificially lignified cell walls from 99 to 116 mg/g. Although PME treatment slightly enhanced uronosyl release from nonlignified cell walls, it reduced uronosyl release from artificially lignified cell walls by 55% after 4 h and by 7% after 72 h of enzymatic hydrolysis. Pectin hydrolysis in PME treated cell walls was probably impaired by enhanced benzyl ester cross-linking of uronosyls to lignin via quinone methide intermediates. Variations in uronosyl methylation had little effect on the overall release of total sugars from cell walls.  相似文献