April - June 2007 - Kasetsart University

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206 To achieve the high fruit quality, high total soluble solid (TSS) at the range of 12-14% and relatively low titratable acidity (TA) of citric acid at the range of 0.4-0.6% in pineapple flesh are recommended for pineapple production in Thailand (Thongtham, 1983). Though TSS and TA are eating quality prediction parameters, TSS is the only parameter suitable as a year-round index (Bartolome et al., 1995). Bartolome et al. (1996) found that TSS in pineapples was positively correlated with total sugars. Beside reflecting fruit quality, TA also indicates the sourness. In pineapples, TA is reported as citric acid, not malic acid. It varies primarily with fruit developmental stages but does not relatively respond to short-term environmental changes, while the malic acid varies with environmental changes especially the light (Singleton and Gortner, 1965). Many factors including ethephon have affected pineapple fruit quality (Bartholomew et al., 2003). An application time and the quantity of ethephon have influences on the quality of fruit. Too early application causes the reduction in size and weight of crown and fruit, whereas low TSS and high TA contents are also found (Audinay, 1970; Chalermglin, 1979). TSS is highly correlated with test-panel eating quality (Smith, 1988) and with total sugars (Bartoleme et al., 1996). In pineapple fruits, fructose, sucrose, and glucose play important roles in flavor characteristics and are major sugars which vary according to the stage of fruit development. Sucrose content is lowest in the flesh during the early stage of fruit growth but rapidly increases at 6 weeks before harvest and becomes predominant in mature fruit. In the early stage, glucose is slightly higher than fructose and remains relatively constant through development while fructose slightly increases at 2 weeks before harvest (Chen and Paull, 2000). The changes in total sugar contents are affected by the developmental stage of fruits, climates, and varieties (Bartoleme et al., 1996), nevertheless the change of each sugar <strong>Kasetsart</strong> J. (Nat. Sci.) 41(2) content in ethephon-treated pineapple fruits has not been reported. In a sink organ, sugar accumulation is related to the presence of sucrose metabolizing enzymes. One of them is sucrose synthase (SuSy) (Taiz and Zeiger, 1998) which reversibly converts sucrose and UDP to fructose and UDP-glucose. SuSy is important in cell metabolism not only in sink strength (Nguyen-Quoc and Foyer, 2001) but also in cell wall synthesis (Nakai et al., 1999; Ruan et al., 2003), and starch synthesis (D / Aoust et al., 1999). Furthermore, it accumulates sucrose in edible tissue of satsuma mandarin fruit (Komatsu et al., 2002) and saves ATP in glycolysis pathway (Huber and Azakawa, 1986). Chen and Paull (2000) reported that in pineapple fruits SuSy activity was higher at young stage, lower at 6 weeks before harvest, and then constant till harvesting time. The change of SuSy activity in ethephon treated fruit has also not been reported. The objective of this work is to answer the question if ethephon could increase TSS, TA, sugar content and SuSy activity in pineapple fruit. MATERIALS AND METHODS Plant and fruit materials Field-grown ‘Pattavia’ pineapple [Ananas comosus L. (Merr.) cv. smooth cayenne] planted at Sam Praya district, Petchburi Province, Thailand, were used. Forcing of pineapple inflorescence was done in the evening of November 18, 2002, by spraying 50 ml of 250 mg/l ethephon (a.i. 48% w/v) including 3% (w/v) urea on shoot. The experimental design used in this study was split plot design. Main plot was ethephon concentration of 0 and 500 mg/l by spraying 50 ml volume per fruit at the age of 110 days after forcing (DAF). Pineapple fruit at this age is pointed-eyes stage 3 according to the Dole Company, Thailand, which is the last stage of pointed-eyes pineapple (immature) and thereafter the eyes will become flatted. Sub-plot was
harvesting time which started from 124 DAF until 152 DAF. Three replications, 8 fruits each, were analyzed. Fruit samples were brought to laboratory and cut transversely into 3 sections after the size and weight of crowns and fruits were measured. Only the flesh of the middle section was used in this study. A half of the flesh was crushed and the juice was then used for determination of TSS and TA. The other half, sliced into small pieces, was used for the determination of the sugar content and sucrose synthase activity. These sliced fleshes of 8 fruits were pooled together as one of three replications at each harvesting time. The tissues were then frozen immediately in liquid nitrogen and stored at -80°C until use. Soluble sugar content TSS was determined from extracted juice using hand sugar refractometer. Soluble sugars in the form of sucrose, fructose and glucose were extracted following the method of Chen and Paull (2000). After extraction, the solution was filtered through a 0.45 mm filter, and 20 ml was injected and analyzed with HPLC by using a Waters 2690 Separation Model instrumented with a Waters 410 Differential Refractometer detector, employing a Sugar-PAK I (Waters Associates, Milford, USA) column of stainless steel (300 mm length × 6.5 mm internal diameters). The eluting buffer was 0.1 mM calcium EDTA and the flow rate was 0.5 ml/min. Experiments were performed at 90°C. Soluble sugars were quantified by comparing the peak areas with external sucrose, glucose and fructose standard solutions (Sigma Co., Ltd.). Titratable acidity TA was analyzed from extracted juice after the determination of TSS contents and reported as citric acid according to AOAC (1990). Sucrose synthase determination Sucrose synthase (SuSy) in frozen flesh tissue was extracted as described by Chen and <strong>Kasetsart</strong> J. (Nat. Sci.) 41(2) 207 Paull (2000). The extracted solution was desalted by Hitrap ® Desalting column (Amersham Biosciences) and 50 µl of desalted mixture was used to determine the enzymatic activity in synthesis direction according to the method of Hubbard et al. (1989), as modified by Chen and Paull (2000). Statistical analysis All data were analyzed the variance (ANOVA) using statistical analysis software of IRRISTAT version 93-3. RESULTS AND DISCUSSION The last harvesting time in this study (152 DAF) was planned to coincide with commercial harvesting time. The commercial harvesting index for cannery fruit industry is apparent when fruits reach full-size and the shell color at the basal portion starts to change. The effects of ethephon and harvesting time on fruit quality, sugar content and SuSy activity after treating at 110 DAF are shown in Table 1. Ethephon concentration did not reduce the size and weight of the crowns and fruits. The crowns and fruits continued to develop after the treatment and the crowns reached a full-size one week (138 DAF) before the fruits did (145 DAF). Maximum growth of the crowns indicated that the fruits were nearly ready for harvest (Paull and Reyes, 1996). The concentration of ethephon plays a significant role in increasing the mean of TSS contents (11.02° Brix) when compared with the mean of untreated fruits (8.90°Brix). The mean of TA and sugar contents including SuSy activity did not change, compared with untreated fruits. The harvesting time at 145 DAF provided the highest TA, TSS and sucrose contents of 0.62% citric acid, 12.16° Brix and 54.12 g/kg FW, respectively (P
Page 1 and 2: April - June 2007 Volume 41 Number
Page 3 and 4: KASETSART JOURNAL NATURAL SCIENCE T
Page 5: Kasetsart J. (Nat. Sci.) 41 : 205 -
Page 9 and 10: y Chen and Paull (2000). Figure 1 a
Page 11 and 12: pineapple fruit allowed the accumul
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Page 15 and 16: Kasetsart J. (Nat. Sci.) 41(2) 215
Page 17 and 18: Cluster analysis Cluster analysis u
Page 21 and 22: Table 3 (Continued) 1 2 3 4 5 6 7 8
Page 25 and 26: CONCLUSION AFLP markers classified
Page 29 and 30: difference of soil texture used in
Page 31 and 32: under wet soil condition planting.
Page 33 and 34: tropics. Following the expansion, w
Page 35 and 36: sealed in a plastic box with 1 cm w
Page 37 and 38: moisture content increment after so
Page 39 and 40: Frequency Frequency 30 20 10 0 20.0
Page 41 and 42: School, Kasetsart University. The a
Page 43 and 44: for combining ability of lines (Lam
Page 45 and 46: selective mass sibbing within indiv
Page 47 and 48: Although most of S 2-interfamily hy
Page 49 and 50: composite sets as used in this stud
Page 53 and 54: days. The numbers of calli producin
Page 55 and 56: the report of Ching (1982) showing
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clearly amplified bands generated b
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caused by either the recombination
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Kuhlmann, V. and B. Foroughi-Wehr.
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Xanthomonas fuscans subsp. aurantif
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Kasetsart J. (Nat. Sci.) 41(2) 265
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was collected and washed with 70% e
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expected size was amplified with 35
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eaction technique has been used for
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Schaad, N.W., D. Opgenorth and P. G
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MATERIALS AND METHODS Model descrip
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calculated TF value calculated TF v
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sincere gratitude and deep apprecia
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1989). In monogastrics, the inclusi
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of all LLS samples in this study we
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Melbourne, Parkville, Victoria. Goe
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considered responsible for low prod
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mineral supplementation suggested b
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Body weight chane (kg/head) 32 30 2
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CONCLUSION AND RECOMMENDATION With
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SAS. (Statistical Analysis System).
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genes covering a variety of desirab
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mg/l NAA and 0.5 mg/l zeatin) incub
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5. Purification by various sucrose
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as the culture period increased. So
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culture, pp. 1-20. In L.C. Fowke an
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Kasetsart J. (Nat. Sci.) 41 : 311 -
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GC. Analytical methods Total carboh
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ash. The crude hot water polysaccha
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spirulan (H-SP), and a desulfated c
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cells often displayed an increased
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LITERATURE CITED Bell, T.A. and D.V
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for alternative sources of supply.
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BR2.1.2 formed the same clade with
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supplement with glutamate (Iida et
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optimal for S. limacinum BR2.1.2 fo
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fluorescent lamp at 1.5 kLux develo
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Wisconsin, USA). Total extracted RN
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RESULTS Cloning and sequencing of m
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Expression of rmIL-2 and purificati
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other strains of mice have differen
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dose interleukin-2 therapy promotes
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The chitosano-oligosaccharides are
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enzyme and cells were maximized by
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of crude chitosanases. Fortunately,
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Relative activity (%) 100 80 60 40
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Uchida, K. Tateishi, O. Shida and K
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MATERIALS AND METHODS 1. Materials
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without coating and coated with pec
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in Table 5-7. It was found that the
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the cultures at 10,200 × g for 15
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incubation and reached the final pH
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y lysine- and tyrosine-decarboxylas
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during the stages of ripening as su
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As the 25 companies were divided in
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All the data comes up with informat
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as piece “A” or straight as pie
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et al. (1998); Zeng (2000); and Tal
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p 1, i * Kasetsart J. (Nat. Sci.) 4
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c ≤ c2 jq2 j n q p k p * 2, j , ,
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algorithm would consider RM 5, prio
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the maximum deviation of about 10%.
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Stock Quantities Using Heuristic Op
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which dynamically and automatically
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2. Framework architecture and compo
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Risk (VaR) calculation which was im
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Throughput (job/sec) 7 6 5 4 3 2 1
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Speed up 40 35 30 25 20 15 10 5 0 F
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and discovery, resource selection a
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April - June 2007 - Kasetsart University

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