MMP-2、MMP-9及TIMP-1、TIMP-2在TPV感染OMK细胞中的表达及其与感染的关系

【目的】研究在特纳河痘病毒(Tanapox virus,TPV)感染枭猴肾上皮细胞(Owl monkey kidney epi-thelial cells,OMK)过程中,基质金属蛋白酶-2(Matrix metalloproteinase-2,MMP-2)、MMP-9和其组织抑制剂(Tissueinhibitor of metalloproteinase,TI MP)TI MP-1、TI MP-2的表达变化及其与感染的关系。【方法】用MMPs高特异性抑制剂(MMP-2Ⅱ、MMP-9Ⅰ)降低MMP-2或MMP-9的活性,研究其对TPV感染的影响和对OMK细胞的毒性。采用明胶酶谱法检测MMP-9和MMP-2在TPV感染过程中蛋白质水平的变化,并应用实时荧光定量PCR方法检测TPV感染中TI MP-1和TI MP-2 mRNA表达水平的变化。【结果】MMP-2和MMP-9的高特异性抑制剂对TPV感染具有显著抑制效果,且对OMK细胞没有毒性作用。在TPV感染OMK细胞过程中,MMP-2和MMP-9蛋白水平升高,而TI MP-1和TI MP-2的mRNA表达水平下降。【结论】MMP-2和MMP-9参与TPV感染,可能对病毒的感染具有促进作用。MMP-2、MMP-9和TI MP-1、TI MP-2比例失衡,造成MMP-2和MMP-9相对"过盛",这可能是MMPs促进TPV感染的重要机制。     

Starch and dry matter content of Netted Gem in relation to French fry texture

Studies were made on the relation of French-fry texture to solids content and to starch granule size in stored Netted Gem potatoes. Texture as evaluated both by a sensory panel and by an objective method was positively correlated with the percentages of starch granules in the 31–44 and 22–31 micron ranges. The usual positive correlations of texture with starch content, dry matter content, and specific gravity were in evidence. In limited trials, greater starch viscosiy and swelling power were associated with poorer texture. Heating time required to reach maximum viscosity was also related to texture, the longer heating times being associated with better texture.     

Simcoe: A new early-maturing,chipping potato variety

Simcoe, a round, white, early potato variety with excellent boiling, baking and chipping qualities, was released by the University of Guelph, Agriculture Canada and the Ontario Ministry of Agriculture and Food in 1981. Yield is comparable to that of Norchip while the chip color ratings and specific gravity are higher. Simcoe is resistant to mild mosaic and late blight, moderately resistant to common scab and moderately susceptible toRhizoctonia. It is susceptible to virus leafroll but resistant to net necrosis from current season infection.     

Response of three cereal crops in continuous arable or ley-arable rotations to fertilizer nitrogen and soil nitrogen at Rothamsted's Woburn Ley-arable experiment

Rothamsted's Woburn Ley-arable experiment, started in 1938 on a sandy loam soil, provides valuable real-world data on the effects of all-arable and ley-arable rotations. In this study, six rotations were compared from 1973 to 2001. Two had 3-year arable “treatment” crops, two had 3-year leys, and two had 8-year leys; the leys being all-grass given fertilizer nitrogen (Ln3 and Ln8), or grass/clover (Lc3 and Lc8). Here, we present the yields of two test crops, winter wheat (1981–2000) followed by spring barley (1982–1991) or winter rye (1997–2001) in each of the six rotations, and their response to four rates of fertilizer N and soil N. From fitted yield/N response curves, we show that maximum wheat yields were least (7.10 t ha⁻¹) in the AB rotation, slightly higher, but not significantly so (7.65 t ha⁻¹) following Ln leys but significantly higher (8.12 t ha⁻¹) following Lc leys. Significantly less fertilizer N (30 kg ha⁻¹) was needed to achieve the higher yields following Lc leys. Yields of the second cereal following the leys were 0.3–0.8 t ha⁻¹ higher than those in the AB rotation; these increases were not statistically significant. However, significantly less fertilizer N, 26–38 kg N ha⁻¹, was required to achieve those yields. There was no difference found between the type of ley. The initial benefit of the Lc leys was short-lived. If leys are to be introduced into mainly arable farming systems, they may need to be subsidized to make them financially viable.     

Importance of Protein‐Rich Components in Emulsifying Properties of Corn Fiber Gum

Purified corn fiber gum (CFG‐F) isolated from fine (kernel endosperm‐derived) corn fiber that contained ≈2% residual protein was extracted with 70% aqueous ethanol. The aqueous ethanol extract (AEE), which contained 19.5% of the total CFG, contained a high percentage of the proteinaceous material present in the original gum sample. The AEE gum contained 6.81% protein by weight. The residue (R), which constituted 66% of the total CFG‐F, contained only 0.55% of protein. The emulsifying properties of R and AEE in a model oil‐in‐water emulsification system were studied by measuring turbidity after 1, 2, and 3 weeks, particle size after 4 weeks, and by confocal laser scanning microscopy after three months of storage at room temperature. These gums were compared with the standard well‐known emulsifiers native acacia gum (NAG) and modified acacia gum (MAG). The results indicate that although AEE contains protein‐rich components, it is not as good an emulsifier as the residue which contains only 0.55% of protein. However, emulsions prepared with the whole (unfractionated) CFG‐F under similar conditions were more stable showing higher turbidity and smaller particles size than those prepared with either R or AEE.     

DETERMINATION OF CANINE PROSTATIC VOLUME USING TRANSABDOMINAL ULTRASONOGRAPHY

The prostate gland from cadavers of 12 intact adult male dogs euthanized less than 3 hour were used to compare prostatic volume measured by ultrasonography to volume measured by water displacement, and to determine specific gravity of the canine prostate. Prostate glands were scanned by transabdominal ultrasonography with a 4-7 MHz curved linear array transducer. The greatest craniocaudal (L), transverse (W), and dorsoventral (D) diameters of the prostate were recorded. Prostatic volume was calculated using formulas for an ellipsoid and for a box. Prostate glands were removed, and the prostate weight was measured and prostatic volume was measured by water displacement. The mean +/- SD specific gravity of the prostate was 1 +/- 0.05 (range = 0.90 to 1.09) g/cm. There were positive correlations (R2 = 0.94) between prostatic volume calculated from ultrasound measurement and measured volume. Measured prostatic volume (VM) can be predicted using the formula: VM = [1/2.6 (L x W x D)] + 1.8 (cm3).