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51.
52.
Ovaries of two goats with persistent corpus luteum were studied by histochemical methods. Lutein cells showed moderate alkaline phosphatase and acid phosphatase activity associated with strong delta 5-3β-hydroxysteroid dehydrogenase and succinic tetrazolium reductase activity. The results are interpreted as an indication that the corpus luteum was functioning.  相似文献   
53.
Principal component analysis (PCA) was used to identify the main sources of variation in the Fourier transform infrared (FT-IR) spectra of 329 wines of various styles. The FT-IR spectra were gathered using a specialized WineScan instrument. The main sources of variation included the reducing sugar and alcohol content of the samples, as well as the stage of fermentation and the maturation period of the wines. The implications of the variation between the different wine styles for the design of calibration models with accurate predictive abilities were investigated using glycerol calibration in wine as a model system. PCA enabled the identification and interpretation of samples that were poorly predicted by the calibration models, as well as the detection of individual samples in the sample set that had atypical spectra (i.e., outlier samples). The Soft Independent Modeling of Class Analogy (SIMCA) approach was used to establish a model for the classification of the outlier samples. A glycerol calibration for wine was developed (reducing sugar content < 30 g/L, alcohol > 8% v/v) with satisfactory predictive ability (SEP = 0.40 g/L). The RPD value (ratio of the standard deviation of the data to the standard error of prediction) was 5.6, indicating that the calibration is suitable for quantification purposes. A calibration for glycerol in special late harvest and noble late harvest wines (RS 31-147 g/L, alcohol > 11.6% v/v) with a prediction error SECV = 0.65 g/L, was also established. This study yielded an analytical strategy that combined the careful design of calibration sets with measures that facilitated the early detection and interpretation of poorly predicted samples and outlier samples in a sample set. The strategy provided a powerful means of quality control, which is necessary for the generation of accurate prediction data and therefore for the successful implementation of FT-IR in the routine analytical laboratory.  相似文献   
54.
1. Despite the importance of Llangorse Lake as the largest natural body of fresh water in South Wales, no long‐term limnological project has ever been planned for the lake. 2. A mass of data is available from sampling carried out at intervals since 1961, but these visits were for various reasons and used widely differing levels of expertise. However, from these data some indications of seasonal variations, effects of climate and human interference on the lake system over 30 years have been inferred. 3. Depth soundings revealed the general shallowness of the lake with two deeper basins. Wind action oxygenated the water and stirred up sediments releasing nutrients and resting algal stages into the water column. Periods of thermal stratification were transient in summer. Secchi disc and light readings showed greatest light penetration in April/May. The lake water remained alkaline throughout. Dissolved ammonia values were low in the 1960s, increased in the 1970s and decreased again in the 1980s. Nitrite‐ and nitrate‐nitrogen showed a converse pattern over the years. Phosphate (PO4 P) and silica (SiO2) values were highest in the 1960s, showed a decrease in the 1970s and early‐1980s, and rose again towards the end of the decade, as did the chloride values. Seasonal fluctuations of all nutrients were observed. 4. Diatoms dominated the phytoplankton, with highest production in summer and early autumn. The Cyanobacteria (blue–green algae) produced blooms in the 1960s and 1970s, but Chlorophyta (green algae) increased over the years and dominated in the 1980s after a diversion of sewage from the lake. Diatom production followed a vernal and late summer periodicity common in temperate lakes. Results from diatom stratigraphy of the deep sediment cores indicated a change from epiphytic to planktonic species related to land‐use change and a subsequent increase in soil erosion and turbidity. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   
55.
Journal of Plant Diseases and Protection - In Mexico, okra (Abelmoschus esculentus L.) is grown mainly for export, but its production is affected by various pests and diseases. Plants with mosaic...  相似文献   
56.
狗蔷薇不定根可被噻苯隆(TDZ)高效诱导形成类原球茎,深入探讨其诱导阶段的分子生物学机制,有利于指导切花月季建立类似高效再生和遗传转化体系.快速、准确克隆和筛选狗蔷薇类原球茎发生的关键基因是进行分子生物学水平研究的一个重要前提.利用苹果(Malus×domestica)、桃(Prunus persica)和草莓(Fragaria vesca)高同源性基因5'UTR(非翻译区)的相对保守性,在其内保守区域设计上游简并引物,以M-MLV逆转录酶反转录合成cDNA为模板,直接扩增蔷薇科植物狗蔷薇(Rosa canina)RcPIN1(pin-formed)和RcPLT(plethora)基因5’末端,大大减少了获取众多目的基因全长的时间及成本.结果显示,在狗蔷薇RcPIN1和RcPLT基因与其对应苹果、桃和草莓高同源性基因的5'UTR内,很多区域表现出较高保守性,表明在5'UTR相对保守区域设计上游简并引物扩增目的基因5’末端的合理性.与常规5'CDNA末端快速扩增技术(5’RACE)相比,本方法无需对cDNA模板5’末端加尾同聚物和引入锚定引物,即不必使用昂贵的5’RACE试剂盒,具有快捷、节约等优点,是一种获取蔷薇科植物基因5'末端的可行途径.  相似文献   
57.
The aim of this study was to evaluate the effect of rosemary essential oils (REO) and the forage nature on ewes' performances, immune response and lambs' growth and mortality. Forty‐eight dairy ewes (Sicilo‐Sarde) were fed oat‐hay or oat‐silage supplemented with 400 g of concentrate during pregnancy and 600 g during postpartum. The experimental concentrate contained the same mixture as the control (barley, soybean meal and mineral vitamin supplement) more 0.6 g/kg of REO. Two groups were obtained with each forage (Hay groups: H‐C and H‐REO; Silage groups: S‐C and S‐REO). REO increased the dry matter (DM) intake, the nitrogen intake and retention being higher with the silage groups (P < 0.05). REO increased solid non‐fat (P = 0.004) and fat contents of colostrum which was higher with hay (P = 0.002). REO decreased lamb mortality (P < 0.05) which averaged 21% for control groups and 6% for H‐REO, while no mortality was recorded with S‐REO. REO dietary supply improved forage intake and tended to ameliorate colostrum production; it could be a natural additive to improve ewes' performances.  相似文献   
58.
Histochemical techniques were applied to whole mounts, to study the distribution of the enzymes alkaline phosphatase, acid phosphatase, adenosine triphosphatase, 5'-nucleotidase and glucose-6-phosphatase in the organs and tissues of a viviparous monogenean, Macrogyrodactylus clarii Gussev, 1961, from the gills of the North African catfish Clarias gariepinus (Burchell) in Egypt. The following organs and tissues were studied: head region, anterior adhesive glands, mouth region, pharynx, intestine, testis, vesicula seminalis, male accessory gland, male accessory reservoir, copulatory organ, receptaculum seminis, egg-cell forming region, embryonic cells, excretory system, nerve cells, haptor, muscle fibres and subtegumental cell bodies (cytons). The enzymes showed marked differences in their activities among the studied organs and tissues. Alkaline phosphatase and acid phosphatase activities were detected in many organs and tissues, while the activities of adenosine triphosphatase, 5'-nucleotidase and glucose-6-phosphatase were restricted to a few organs. Although no positive reaction for any enzyme was observed in the anterior adhesive gland cells, a positive reaction for acid phosphatase was detected in the anterior adhesive areas. All enzymes showed marked activity in the digestive and excretory systems. The distribution of the enzymes in the tissues and organs of M clarii is compared with those of other monogeneans, including other gyrodactylids parasitizing the same host fish. Some possible functions of the enzymes are discussed.  相似文献   
59.
Phenolic acids, which are generally esterified with tartaric acid, are natural constituents of grape must and wine and can be released as free acids (principally p-coumaric, caffeic, and ferulic acids) by certain cinnamoyl esterase activities during the wine-making process. Some of the microorganisms present in grape can metabolize the free phenolic acids into 4-vinyl and 4-ethyl derivatives. These volatile phenols contribute to the aroma of wine. The Saccharomyces cerevisiae phenyl acrylic acid decarboxylase gene (PAD1) is steadily transcribed, but its encoded product, Pad1p, shows low activity. In contrast, the phenolic acid decarboxylase (PADC) from Bacillus subtilis and the p-coumaric acid decarboxylase (PDC) from Lactobacillus plantarum display substrate-inducible decarboxylating activity in the presence of phenolic acids. In an attempt to develop wine yeasts with optimized decarboxylation activity on phenolic acids, the padc, pdc, and PAD1 genes were cloned under the control of S. cerevisiae's constitutive phosphoglyceratekinase I gene promoter (PGK1(P)()) and terminator (PGK1(T)()) sequences. These gene constructs were integrated into the URA3 locus of a laboratory strain of S. cerevisiae, Sigma1278b. The overexpression of the two bacterial genes, padc and pdc, in S. cerevisiae showed high enzyme activity. However, this was not the case for PAD1. The padc and pdc genes were also integrated into an industrial wine yeast strain, S. cerevisiae VIN13. As an additional control, both alleles of PAD1 were disrupted in the VIN13 strain. In microvinification trials, all of the laboratory and industrial yeast transformants carrying the padc and pdc gene constructs showed an increase in volatile phenol formation as compared to the untransformed host strains (Sigma1278b and VIN13). This study offers prospects for the development of wine yeast starter strains with optimized decarboxylation activity on phenolic acids and the improvement of wine aroma in the future.  相似文献   
60.
The edible mushroom Morchella esculenta is among the most highly prized and morphologically recognizable fungi in the world. We describe the isolation from a polar extract of M. esculenta carpophores of a high-molecular-weight galactomannan, about 1.0 million Da, that exhibits immunostimulatory activity. At 3.0 microg/mL the galactomannan polysaccharide increased NF-kappa B directed luciferase expression in THP-1 human monocytic cells to levels 50% of those achieved by maximal activating concentration (10 microg/mL) of lipopolysaccharide. This galactomannan comprises about 2.0% of the dry fungal material weight, and its glycosyl components include mannose (62.9%) and galactose (20.0%).  相似文献   
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