南瓜果实发育过程中肌醇、多糖和还原糖含量的变化

 以印度南瓜和中国南瓜为试材,研究了果实发育过程中肌醇、多糖和还原糖含量的变化。结果表明：不同南瓜品种果实中肌醇、多糖和还原糖的含量随着果实的生长发育逐步增加,肌醇含量,印度南瓜在果实发育45 d 时达到峰值,中国南瓜则在35 d 时达到峰值,此后含量均逐步下降;多糖含量,印度南瓜在果实发育55 d 时达到峰值,中国南瓜则在40 d 时达到峰值,此后含量也均呈下降趋势;还原糖含量,印度南瓜在果实发育25 d 时达到峰值,中国南瓜则在35 d 时达到峰值,随后含量均逐步下降;各品种果实均在采收贮藏10 d 时还原糖含量又开始增加,呈现“升、降、升”的变化趋势;不同南瓜品种果实中肌醇、多糖和还原糖的含量存在差异。     

籽用和肉用南瓜品种果实生长发育过程中营养成分的比较分析

以籽用和肉用南瓜品种为试材,分析果实生长发育过程中主要营养成分及其变化规律。结果表明：籽用南瓜品种和肉用南瓜品种的可溶性糖、β-胡萝卜素和干物质含量在果实生长发育过程中呈现相似的变化趋势,随着果实的逐渐成熟,含量逐渐增加,但各营养成分在不同品种中增长速率不同|淀粉、VC、果胶含量在肉用南瓜品种和籽用南瓜品种果实生长发育过程中变化规律不同,其中印度南瓜籽用品种98-2-2和银辉1号淀粉含量在果实发育过程中呈现不断增长的趋势,而美洲南瓜籽用品种金辉2号、0516-2和印度南瓜肉用品种锦元、红栗淀粉含量呈现先升高后下降的变化趋势|不同类型品种VC含量变化趋势不同,其中印度南瓜籽用品种98-2-2、银辉1号和肉用南瓜品种锦元、红栗VC含量的变化趋势相同,均呈现先降后升的变化趋势,美洲南瓜籽用品种金辉2号和0516-2中VC含量变化趋势大致相同,呈现逐渐下降的变化趋势。除了金辉2号果实中果胶含量呈现逐渐增加的趋势外,其余5个品种果实中果胶含量均呈现先升高后下降的变化趋势。     

贮藏温度对笋瓜（印度南瓜）果实呼吸速率和品质指标的影响

以青农绿栗1号（简称绿栗）和桔栗3号（简称桔栗）两个印度南瓜为材料,研究了常温和低温贮藏条件下印度南瓜品种呼吸速率和品质指标的变化规律。结果表明：低温贮藏条件下供试印度南瓜果实的呼吸速率变化较小|而常温下贮藏的呼吸速率呈上升趋势,并于贮藏后25 d达到高峰。印度南瓜果实中的多糖、淀粉含量均呈现下降的趋势|而类胡萝卜素含量则呈增加的趋势,且以常温贮藏条件下增加较快。可溶性糖、可溶性固形物和可溶性蛋白质含量均呈先上升后下降的趋势。除类胡萝卜素外,绿栗果实中多糖、淀粉、可溶性糖、可溶性固形物和可溶性蛋白质含量均显著高于桔栗。低温贮藏条件下印度南瓜果实多糖、淀粉、可溶性糖、可溶性固形物、类胡萝卜素和可溶性蛋白质含量均高于常温贮藏。     

火龙果果实发育过程中淀粉与可溶性糖含量变化及其相关性分析北大核心

研究金都一号和越南白肉火龙果不同发育时期果实中淀粉与可溶性糖含量变化趋势,旨在为火龙果果实品质提升提供科学依据。以金都一号和越南白肉为试验材料,分别测定7个发育时期的果实中淀粉、蔗糖、果糖和葡萄糖含量等变化趋势。结果表明,金都一号和越南白肉火龙果果实淀粉含量均呈单峰型变化,二者均从花后5 d开始迅速积累淀粉,分别于花后20 d和15 d达到峰值,之后淀粉含量迅速降低,成熟期淀粉含量较少。金都一号火龙果蔗糖含量在花后10 d和30 d分别出现2个高峰值,而越南白肉火龙果的蔗糖含量呈现先降后升再降的变化趋势,二者蔗糖含量均在花后30 d达到最高。2个品种从花后5~15 d期间果实中果糖和葡萄糖含量波动较小,花后20 d果糖和葡萄糖含量均急剧增加。金都一号火龙果果糖和葡萄糖含量分别在花后30 d和35 d达到最高,而越南白肉火龙果的葡萄糖和果糖含量分别在花后30 d和35 d达到最高。相关性分析发现,金都一号火龙果果实淀粉与蔗糖含量变化存在显著负相关关系;越南白肉火龙果的淀粉含量与蔗糖含量呈极显著负相关,与果糖和葡萄糖含量均呈显著负相关。火龙果果实淀粉降解和可溶性糖含量增加存在极显著和显著负相关,为探讨火龙果果实中可溶性糖积累与淀粉降解机制之间的关系提供了理论依据。     

籽用和肉用印度南瓜果实发育过程中淀粉合成途径相关基因的表达分析

以籽用印度南瓜自交系98-2 及肉用印度南瓜自交系312-1 为试材,对印度南瓜果实淀粉含量及淀粉代谢相关基因的表达模式进行研究。结果表明：312-1 和98-2 果实中的总淀粉和支链淀粉积累模式存在明显差异,312-1 中总淀粉和支链淀粉积累模式相似,都是随着果实发育逐渐积累,在授粉后40 d 时达到高峰,随后略有下降,而98-2 中总淀粉和支链淀粉含量一直维持在果实发育初期（授粉后5 d）水平,没有显著积累的过程;在果实发育的各个时期312-1 中总淀粉和支链淀粉含量均极显著高于98-2。2 份材料中直链淀粉的积累模式大致相同,都维持在果实发育初期的积累水平,但在果实发育的各个时期312-1 中直链淀粉含量均显著或极显著高于98-2。在淀粉组成上,2 份材料均是以支链淀粉为主。淀粉合成途径关键酶基因除ISAⅢ、SSSⅡ和SBEⅡ基因外,GPT、AATP、PGM、AGPaseL、GBSSⅠ、SSSⅢ和SBEⅠ基因在2 份材料果实发育过程中的表达趋势相似,其表达量在2 份材料中存在较大差异,结合2 份材料果实中直链淀粉和支链淀粉含量,推测GPT、AATP、AGPaseL、GBSSⅠ、SSSⅡ、SSSⅢ、SBEⅠ和SBEⅡ基因是调控印度南瓜果实中淀粉积累的关键酶基因。     

不同山药品种糖含量的比较分析

采用不同的测定方法,对6个不同山药品种中的还原糖、总糖及粗多糖进行测定。结果表明:不同品种间的糖含量存在一定的差异,其中‘明豆子’中的还原糖、总糖和粗多糖的含量最高,含量分别为0.1485%、0.3812%、0.2246%,其余品种不同的组分含量有所差异,综合分析‘明豆子’的市场开发价值最高。     

南丰蜜桔果实生长发育的研究

本试验以小果系普通南丰蜜桔为试材,研究了其果实的生长发育规律及果实发育期糖、有机酸、维生素C、纤维素及可溶性固形物含量的变化,以探明南丰蜜桔果实发育规律,为改进栽培技术、提高果实品质提供科学依据。研究结果表明:南丰蜜桔果实生长曲线为单S型,相对生长率5月最高,10月最低,成熟前略有回升,总体呈现下降趋势;随着果实的发育,可溶性糖、还原糖及可溶性固形物含量迅速增加且持续到果实成熟时达最高值,而蔗糖含量在9月底10初达到最高值,随后下降,成熟前略有提高;有机酸含量在发育早期增加,8月初至9月中旬达最高值且变化缓慢,之后急剧降低;果实维生素C含量总体表现为先增加后降低,于10月上中旬达最大值;果肉纤维素含量随果实发育逐渐降低,成熟时达最低点。     

黑莓果实转色至成熟进程中相关激素含量的变化

以果实硬度差异明显的‘Arapaho’和‘Boysen’黑莓品种为试材,分析比较了二者小核果形成后内源激素乙烯(ETH)、脱落酸(ABA)及油菜素甾醇(BR)含量在果实转色至成熟进程不同发育时期中的动态变化,以期为揭示黑莓果实成熟过程中激素的调控作用提供参考依据。试验表明:高硬度‘Arapaho’和低硬度‘Boysen’分别在花后12d和24d开始转色,转色后各生长发育指标均持续快速增加。‘Arapaho’ETH含量在花后21d和33~36d表现小高峰,完熟时明显下降;‘Boysen’ETH含量在花后15、24、30~33d及完熟时均出现峰值,完熟时ETH含量最高。‘Arapaho’和‘Boysen’果实ABA含量均在小核果形成后初期较低,之后在发育中后期均出现2次峰值,完熟时ABA含量均明显下降。‘Arapaho’和‘Boysen’果实BR含量在小核果形成后初期均逐渐下降,之后在发育中后期均表现为先下降后上升,果实接近完熟及完熟时BR含量均显著下降。试验表明,在‘Arapaho’和‘Boysen’果实发育成熟进程中,3种激素均参与其中,ETH和ABA在果实后期快速发育时含量较高,ABA与黑莓果实完全成熟启动关系更密切,2个品种在ETH含量变化动态上差异较大,而在ABA和BR含量变化动态趋势上具一定相似性。     

早春栽培的印度南瓜果实淀粉积累相关酶的活力

为选育果实淀粉含量高、适于早春日光温室栽培的印度南瓜,以Agol、雪2父、S8844、无名绿4份高代自交系种质为试材,研究果实发育期间(授粉后14、21、28、35、42 d)淀粉含量动态变化及其与AGPase、GBSS、SSS、SBE、α-淀粉酶、β-淀粉酶等酶活力的相关性.结果表明,果实发育42 d后,高淀粉含量种...     

西瓜果实发育过程中不同糖含量的变化

对不同西瓜品种果实发育过程中果糖、葡萄糖、蔗糖和总糖含量的动态变化进行了分析,以探讨西瓜不同糖的变化规律,旨在为西瓜品质改良提供依据。结果表明:西瓜果实总糖、果糖和葡萄糖含量变化趋势基本一致,幼果期较低,随后缓慢积累,果实膨大期有所下降,成熟过程迅速积累,完熟期到达峰值,过熟期含量开始下降;西瓜果实蔗糖含量基本呈"S"型曲线变化,幼果期含量较低,随后缓慢积累,果实膨大期迅速积累,完熟期达到峰值,过熟期含量开始下降。西瓜果实中总糖、果糖、葡萄糖在授粉后33d左右达到峰值,蔗糖含量在授粉后30d左右达到峰值。     

Relationship between renal hypertension and cardiac α1-adrenoceptor autoantibodies in rats

AIM: To examine the autoantibody against α₁-adrenoceptor and its biologic activities during the development of renal hypertension. METHODS: Renal hypertension of rat was achieved by clipped renal artery, the titre of autoantibody to α₁-adrenoceptor was detected using ELISA immunoassay. Furthermore, the biological offects of these autoantibodies on cultured cardiomyocytes were also examined. RESULTS: After two weeks of clipping renal arteries, both the frequency of occurrence and the titre of autoantibodies to cardiac α₁-adrenergic receptor were significantly increased as compared with the control of pre-treatment. The increased autoantibodies lasted for several weeks and then automatically decreased gradually to the pre-clipping level at 12 weeks. The biological effects of these autoantibodies displayed an "agonistic-like" activities on the beating frequency of cultured neonatal cardiomyocytes. CONCLUSION: Autoantibodies against α₁-adrenoceptor may play a role in the elevation of peripheral vascular resistance and in the development of cardiac hypertrophy in rats with renal hypertension.     

Effects of radiation from 188Re on smooth muscle cell proliferation

AIM: Although endovascular radiotherapy inhibits neointimal hyperplasia, the exact alterations induced by β-particles irradiation remain to be elucidated. The objective of this study was to investigate the ability and the cellular mechanism of local β^-particles emission from ¹⁸⁸Re to inhibit vascular smooth muscle cells (SMCs). METHODS: The SMCs in vitro were irradiated by ¹⁸⁸Re with single doses of 2.6 Gy-25.8 Gy. The effects of β-particles on SMCs, such as effective irradiate doses, the period of inhibition for SMCs proliferation, the changes of cell proliferation rate and DNA synthesis rate, cell cycle progression and related gene expression, were investigated by cell count, [³H]-TdR incorporation, cell cycle progression analysis, cell viability and immunocytochemistry, respectivecy. RESULTS: β-particles irradiation with dose of 5.2 Gy could inhibit significantly SMCs proliferation. At dose of 20.6 Gy DNA synthesis inhibitory rate was 92%, SMCs proliferation rate was only 3%. Renoval of ¹⁸⁸Re did not abolish the inhibitory effects of β-particles on SMCs proliferation. The expression of P53 was up regulation and PCNA was down regulation after irradiation. CONCLUSION: β-particles from ¹⁸⁸ Re was significantly effective and permanent in inhibiting SMCs proliferation, and inhibitory effect was in dose-dependet manner ED50was 5 Gy, the best dose to inhibit SMCs proliferation was 20 Gy. β-particles irradiation induced SMCs to occur G₀/G₁ arrest, damaged the ability of SMCs reproliferation and led to cell clonogenic death. P53 and PCNA had regulatiory effects on SMCs proliferation after β-particles irradiation.     

Influence of Mineral Nutrients on Strawberry Fruit Quality and Their Accumulation in Plant Organs

Abstract

This review is based partly on complete articles and partly on abstracts. Three of the 60 articles deal with the total uptake of elements in strawberry plant organs in two different strawberry production systems, both considered as optimal concerning amount and balance of elements. The effect on fruit quality may be dramatic if the level of a particular element is outside this range, but there may also be effects initiated by differences within the optimal range of elements. Most articles refer to product oriented quality, but some focus on consumer oriented quality, as discussed by Shewfelt (1999). The discussion here is on a general basis, so one should keep in mind that there are cultivar differences and that specification of nutrition ideally should mirror the needs of a single cultivar, or a group of cultivars with similar requirements. Also, to get a complete understanding of the subject future reviews should embrace a broader access of information including the effect on plant development of individual elements, such as the role of calcium in fruit firmness and its importance in cell wall structure. However, the intention here is to narrow the information to results that suggest a direct connection between nutrient uptake and fruit quality.     

Effect of L-Arg on plasma content of endothelin and expression of c-fos mRNA in the left ventricle of rats with renovascular hypertensive hypertrophy

AIM:To study the effect of L-Arg on plasma content of endothelin (ET) and the expression of proto-oncogene c-fos mRNA in the left ventricle of rats with renovascular hypertensive hypertrophy. METHODS: The level of c-fos mRNA were measured by in situ hybridization. The ET in plasma were measured by radioimmunoassay. RESULTS:After eight weeks of treatment with L-Arg, the expression of c-fos decreased markedly (P＜0.01). The ET content in plasma also decreased significantly by L-Arg(P＜0.01).CONCLUSION: Plasma ET content and the expression of c-fos in the left ventricle of rats with renovascular hypertensive hypertrophy could be decreased by L-Arg administration.     

Mixed-severity fire regime in a high-elevation forest of Grand Canyon,Arizona, USA

Fire regime characteristics of high-elevation forests on the North Rim of the Grand Canyon, Arizona, were reconstructed from fire scar analysis, remote sensing, tree age, and forest structure measurements, a first attempt at detailed reconstruction of the transition from surface to stand-replacing fire patterns in the Southwest. Tree densities and fire-/non-fire-initiated groups were highly mixed over the landscape, so distinct fire-created stands could not be delineated from satellite imagery or the oldest available aerial photos. Surface fires were common from 1700 to 1879 in the 4,400 ha site, especially on S and W aspects. Fire dates frequently coincided with fire dates measured at study sites at lower elevation, suggesting that pre-1880 fire sizes may have been very large. Large fires, those scarring 25% or more of the sample trees, were relatively infrequent, averaging 31 years between burns. Four of the five major regional fire years occurred in the 1700s, followed by a 94-year gap until 1879. Fires typically occurred in significantly dry years (Palmer Drought Stress Index), with severe drought in major regional fire years. Currently the forest is predominantly spruce-fir, mixed conifer, and aspen. In contrast, dendroecological reconstruction of past forest structure showed that the forest in 1880 was very open, corresponding closely with historical (1910) accounts of severe fires leaving partially denuded landscapes. Age structure and species composition were used to classify sampling points into fire-initiated and non-fire-initiated groups. Tree groups on nearly 60% of the plots were fire-initiated; the oldest such groups appeared to have originated after severe fires in 1782 or 1785. In 1880, all fire-initiated groups were less than 100 years old and nearly 25% of the groups were less than 20 years old. Non-fire-initiated groups were significantly older (oldest 262 years in 1880), dominated by ponderosa pine, Douglas-fir, or white fir, and occurred preferentially on S and W slopes. The mixed-severity fire regime, transitioning from lower-elevation surface fires to mixed surface and stand-replacing fire at higher elevations, appeared not to have been stable over the temporal and spatial scales of this study. Information about historical fire regime and forest structure is valuable for managers but the information is probably less specific and stable for high-elevation forests than for low-elevation ponderosa pine forests.This revised version was published online in May 2005 with corrections to the Cover Date.     

Compositional and Functional Properties of Saskatoon Berry and Blueberry

Abstract

Saskatoon berry (Amelanchier alnifolia Nutt., Rosaceae) and blueberry (Vaccinium corymbosum L., Ericaceae) are substantially equivalent in all characteristics that are important to the consumer, including fruit color, shape, size, nutrition, texture, and uses. In addition, both fruits are native to North America and they have practically identical historical uses and known health benefits. Their composition, processing, nutritional value and metabolism, intended uses, and levels of undesirable substances are compared.     

瓜叶绿素降解关键酶基因PPH和PAO cDNA片段的克隆与表达初步分析

 以西双版纳黄瓜和‘华黄5号’黄瓜叶片为试验材料,研究了衰老过程中两种黄瓜叶片叶绿素含量变化及脱镁叶绿素脱镁叶绿酸水解酶基因PPH和脱镁叶绿酸a加氧酶基因PAO的表达。结果表明：随着叶片衰老,叶绿素a和叶绿素b含量显著降低,叶绿素a与叶绿素b的比值在0.5左右,推测叶绿素b的含量可能对黄瓜叶片保绿起到重要作用。荧光定量RT-PCR分析结果显示：PPH和PAO在西双版纳黄瓜叶片生长35 d时表达量最高,分别为5.50和1.86;PPH在‘华黄5号’叶片35 d时表达量最高,为7.14,而PAO在35和45 d表达量都很高,分别为3.90和3.91;PPH和PAO在西双版纳黄瓜叶片中的表达量低于在‘华黄5号’中。     

Effects of simvastatin on PDGF-BB and serum-induced proliferation of vascular smooth muscle cells and on the expression of tumor suppressor gene PTEN

AIM:To observe the effect of simvastatin on the proliferation of vascular smooth muscle cells(VSMCs) induced by serum and growth factor PDGF-BB and the effect of simvastatin on the expression of PTEN,a important regulator of G₁/S cell cycle transition. METHODS:The DNA synthesis was determined by [³H]-TdR incorporation, cell cycle was examined with flow cytometry, the protein level of PTEN was measured by Western blot method. RESULTS: (1)Simvastatin inhibited [³H]-TdR incorporation in a dose dependent manner. (2) Flow cytometric DNA analysis revealed that simvastatin induced significantly enhancement of G₀/G₁ phase and decrease in S phase VSMCs.(3)Simvastatin increased protein level of PTEN and mevalonate, a metabolite of HMG-COA, reversed the effect of simvastatin on PTEN protein expression. CONCLUSION:Simvastatin may inhibit proliferation of VSMCs and retarded cell cycle in G₀/G₁ phase by increasing PTEN expression through inhibiting synthesis of mevalonate.     

Cryopreservation of shoot apices of hawthorn in vitro cultures originating from East Asia

The objective of this study was to establish a cryopreservation protocol for hawthorn shoot apices (Crataegus pinnatifida Bge.). Cryopreservation was carried out via encapsulation–dehydration, vitrification, and encapsulation–vitrification on shoot apices excised from in vitro cultures. We began by showing that cold-acclimation enhanced the regrowth of cryopreserved apices from 10.0 to 65.5% in encapsulation–dehydration. We then decided that the encapsulation–dehydration method was an optimal cryopreservation method for hawthorn shoot apices in terms of its high recovery after cryopreservation as well as its ease of use compared with vitrification and encapsulation–vitrification. In encapsulation–dehydration, the protocol leading to optimal regrowth was as follows: after cold-acclimation at 5 °C in the dark for 2 weeks, excised shoot tips were pretreated for 24 h at 25 °C on hormone-free Murashige and Skoog [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiol. Plant. 15, 473–497] (MS) basal medium with 0.4 mol/L sucrose, then encapsulated and precultured in liquid MS medium with 0.8 mol/L sucrose for 16 h at 25 °C. Precultured beads were dehydrated for 6 h at 25 °C in the dessicator containing 50 g silica gel to a moisture content of 15.3% (fresh-weight basis) before cryostorage for 1 h. In addition, we examined the effect of adding glycerol to both the alginate beads and loading solution to enhance regrowth after cryopreservation in encapsulation–dehydration. In the present study, it was shown that adding 0.5 mol/L glycerol resulted in high regrowth percentages (82.5–90.0%) in four Crataegus species.     

Relationships of landscape,prey and agronomic variables to the abundance of generalist predators in cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis>) fields

A two-year field study investigated the possible effects of grain sorghum (Sorghum bicolor [L.] Moench) and uncultivated areas on the abundance of generalist predators in commercially-managed cotton (Gossypium hirsutum L.) fields in Texas, USA. From 63 to 70 fields were sampled for pests and predators over nine consecutive weeks during early stages of cotton development. Additional data on agronomic practices and landscape composition at three spatial scales were also collected for each field. Stepwise regression analyses were used to determine the relationships of landscape, agronomic and prey variables to the abundance of generalist predators. Because the variables most closely linked to predator levels could vary over time, separate regressions were conducted for three time periods corresponding to stages of grain sorghum growth (half-bloom, hard-dough, maturity) in each year. Significant relationships between predator abundance and agricultural landscape composition appear in both years and in all three time periods, but the specific relationships of landscape variables to cotton predator levels differed between and within years. At maturity in 2001, predator levels rose as the amount of uncultivated land from 1.6 to 3.2 km distant and the perimeter shared with grain sorghum increased. During 2002, the area of grain sorghum (half-bloom) and uncultivated land (hard-dough) within 1.6 km of cotton fields were both positively related to predator numbers. Cotton planting dates and the abundance of cotton fleahoppers (Pseudatomoscelis seriatus [Reuter]) were also strongly linked to predator numbers during both years. Results suggest that the total amount of grain sorghum or uncultivated land in an area is more important than the presence of these habitats adjacent to cotton fields, and that landscape composition may sometimes be the most important factor in determining predator abundance.