Analysis of free and esterified ergosterol in tomato products

A new extraction and chromatographic procedure to quantify free and esterified ergosterol in tomato products was devised. The extraction solution was composed of a dichloromethane/methanol mixture in a 2:1 (v/v) ratio. This extraction solvent allowed for higher ergosterol recovery from tomato products (an average of 25% more) compared to hexane, which is frequently employed for ergosterol extraction. Both free and esterified ergosterol were determined by HPLC reverse-phase chromatography employing a Nova-Pak C-18 column (300 x 3.9 mm), filled with 4 mm average particle size and a guard column of the same material. The elution was performed at a flow rate of 1 mL. min(-1) with a linear gradient of solvent A (methanol/water, 80:20, v/v) and solvent B (dichloromethane). The gradient, starting at sample injection, was from 0 to 50% B for 20 min for the free ergosterol analysis and additional 15 min at 50% B to analyze the ergosterol esters. This technique has proven to be more sensitive for ergosterol determination than other reported chromatographic procedures. Moreover, ergosterol esters, extracted from various fungal sources, separated well and were easily quantified.     

Ellagic acid, vitamin C, and total phenolic contents and radical scavenging capacity affected by freezing and frozen storage in raspberry fruit

The ellagic acid, total phenolic, and vitamin C contents in four raspberry cultivars (Heritage, Autumn Bliss, Rubi, and Zeva) grown in Spain were detected and quantified by HPLC in fresh, just frozen, and stored fruits at -20 degrees C for a one year period. Ellagic acid [207-244 mg kg(-)(1) of fresh weight (fw)], total phenolic (137-1776 mg kg(-)(1) of fw), and vitamin C (221-312 mg kg(-)(1) of fw) contents in raw material were higher in the late cultivars Zeva and Rubi than in the early cultivars Autumn Bliss and Heritage. The freezing process slightly affected the values of extracted ellagic acid, total phenolic, and vitamin C content. At the end of long-term frozen storage (12 months), no significant change of total phenolic content extracted was observed, but significant decreases of 14-21% in ellagic acid and of 33-55% in vitamin C were quantified. Free radical scavenging capacity measured as antiradical efficiency (AE) depends on the seasonal period of harvest. Late cultivars, Rubi (6.1 x 10(-)(4)) and Zeva (10.17 x 10(-)(4)), showed higher AE than early cultivars, Heritage (4.02 x 10(-)(4)) and Autumn Bliss (4.36 x 10(-)(4)). The freezing process produced a decrease of AE values in the four cultivars ranging between 4 and 26%. During the frozen storage, the AE values reached after the freezing process remained unchanged.     

Relative abundance and activity of melanized hyphae in different soil ecosystems

Here we report on the frequency of melanized fungal hyphae in 323 soils, covering different land use types. The proportion of total hyphae that was melanized averaged 61%. Arable fields with loamy sand, heathlands and city parks on sandy soils had the highest percentage of melanized hyphae. In addition to the frequency determinations, a microcosm study was performed on the role of melanized hyphae in two different ecosystems: an ex-arable field and a forest. Melanized hyphae appeared to be part of the active hyphae in the forest soil but not in the ex-arable soil. In conclusion, our results indicate that (1) melanized hyphae represent a large proportion of the total fungal biomass in soils and that (2) their function might differ between ecosystems.     

银杏外种皮综合利用的研究

从银杏外种皮中提取的银杏酚酸和白果酚有杀虫、杀菌作用。银杏酚酸和银杏黄素、银杏异黄素混合物对致病性真菌生长有明显抑制作用 ,且有抗过敏、抗炎等作用。同时测定了银杏外种皮中萜内酯的含量和微量元素、氨基酸、蛋白质的含量。结果表明 :银杏外种皮有综合利用和开发的前景     

Galaxies, human eyes, and artificial neural networks

The quantitative morphological classification of galaxies is important for understanding the origin of type frequency and correlations with environment. However, galaxy morphological classification is still mainly done visually by dedicated individuals, in the spirit of Hubble's original scheme and its modifications. The rapid increase in data on galaxy images at low and high redshift calls for a re-examination of the classification schemes and for automatic methods. Here are shown results from a systematic comparison of the dispersion among human experts classifying a uniformly selected sample of more than 800 digitized galaxy images. These galaxy images were then classified by six of the authors independently. The human classifications are compared with each other and with an automatic classification by an artificial neural network, which replicates the classification by a human expert to the same degree of agreement as that between two human experts.     

香龙血树真菌病害的鉴定

1997-2000年在广州地区的香龙血树[Dracaena fragrans(L.)Ker-Gaw.]种植单位共调查到9种真菌病害，即：可可球二孢茎枯病，顶多毛孢叶斑病，弯孢霉灰斑病，弯孢霉褐斑病，炭疽病，拟盘多毛孢叶斑病，拟茎点霉灰斑病，拟茎点霉叶斑病和球壳孢叶枯病，其病原菌分别被鉴定为：可可球二孢（Botryodiplodia theobromaePat.)、龙血树顶多毛孢（Bartalinia dracaenaeaP.G.Xi,Z.D.JiangetP.K.Chi)，弯孢霉[Gurvularia lunata(Walker)Boedijn]、塞河弯孢霉[Curvularia senegalensis(Speg.)Subram]、围小丛壳[Glomerella cingulata(Stonem)Spauld,etSchrenk]，棒孢拟盘多毛孢[Pestalotiopsis clavispora(Atk)Stey]、龙血树拟茎点霉（phomopsis dracaenae Sahni)，龙血树生拟茎点霉（Phomop-sis dracaenicola Z.D.Jiang,P.G.XietP.K.Chi)，龙血树球壳孢（Sphaeropsis dracaenaeP.G.XietP.K.Chi)，对生产影较大的是由可可球二孢引起的茎枯病和由围小丛壳引起的叶部炭疽病。     

苎麻苗期封行期植株营养诊断及调节施肥研究

以“养分指数”为依据对新栽麻和成龄麻苗期、封行期进行植株养分平衡营养诊断,结果表明,各时期养分元素障碍因子对产量与品质的限制程度依次为(1)苗期新栽麻B>Fe>Cu>S,成龄麻N>B>P>Fe>Cu>S;(2)封行期基础肥力较好的土壤上新栽麻Mg,B>Zn>K>Ca,成龄麻Mg,B>Zn>N,P>K>Ca;基础肥力较差的土壤上新栽麻与成龄麻Mg,B>Zn>N,P>K>Ca>     

发展农产品快速检测技术确保饮食安全

发展农产品快速检测技术是一项利国利民的大事 ,不仅是保护消费者利益的重大举措 ,也是推进农业结构调整 ,提高农产品市场竞争力 ,增加农民收入的有效措施。建立与国际接轨的农产品及其加工品质量标准体系和检测监督机制、措施 ,进行农产品品质检测重要性的宣传 ,同时认真贯彻执行《中华人民共和国产品质量法》。引进、吸收和消化国外先进的农产品检测技术和设备 ,利用我国农产品生产和加工的人才优势 ,通过政府资助开展农产品检测研究。加速制定有利于无公害食品发展的扶持政策 ,包括对无公害食品的生产、加工、流通等方面的政策扶持 ,确保广大人民吃上放心食品     

Two reported cytotypes of the emergent orchid model species <Emphasis Type="Italic">Erycina pusilla</Emphasis> are two different species

Each species is characterized by a specific set of chromosomes, which is described as the chromosome portrait or karyotype. In general, such a karyotype is the same for all individuals in the population. An exception to that rule has recently been found in the orchid Erycina pusilla, which has been reported to have two cytotypes with chromosome numbers of 2n = 10 and 2n = 12. Here, we examined the karyotypes of the two cytotypes and found differences in arm ratios and heterochromatin patterns as well as in the presence of satellite chromosomes and in the number and location of rDNA and telomeric repeat sites. These differences are extensive and would have required multiple chromosome rearrangements to generate the differences between the two karyotypes. We also found that F1 hybrids between the parents with the two different chromosome numbers resulted in sterile offspring, in accordance with our previous findings. The combination of hybrid sterility and extensively rearranged chromosomes supports the hypothesis that these two reported cytotypes are, in fact, two different species.