Gluconacetobacter sp. gel_SEA623-2, bacterial cellulose producing bacterium isolated from citrus fruit juice

Cellulose producing bacterial strain was isolated from citrus fruit juice fungus. The isolated strain was identified as Gluconacetobacter sp. gel_SEA623-2 based on several morphological characteristics, biochemical tests, and 16S rRNA conducted. Culture conditions for bacterial cellulose production by SEA623-2 were screened in static trays. Conditions were extensively optimized by varying the kind of fruit juice, pH, sugar concentration, and temperature for maximum cellulose production. SEA623-2 has a high productive capacity in citrus processing medium, but not in other fruits. The optimal combination of the media constituents for bacterial cellulose production is as follows: 10% citrus juice, 10% sucrose, 1% acetic acid, and 1% ethanol at 30 °C, pH 3.5. Bacterial cellulose produced by SEA623-2 has soft physical properties, high tensile strength, and high water retention value. The cellulose produced by the selected bacteria is suitable as a cosmetic and medical material.     

Asymmetric Reduction of Ketones by Biocatalysis Using Clementine Mandarin (Citrus reticulata) Fruit Grown in Annaba or by Ruthenium Catalysis for Access to Both Enantiomers

Biocatalytic reduction of prochiral ketones using freshly ripened clementine mandarin (Citrus reticulata) in aqueous medium is reported. High enantioselectivities were observed, especially for the bioreduction of indanone 3 , tetralone 4 , and thiochromanone 5 with respectively 95%, 99%, and 86% enantiomeric excess (ee). Enantioselective bio‐ and metal‐catalyzed reactions were compared. Chiral ruthenium catalysts afforded good asymmetric inductions (>75% ee) in most cases, enantiomeric excesses depending on the nature of substrate and ligand. N‐aminoindanol prolinamide L³ was revealed as the best ligand for most ketones. Interestingly, for several substrates both enantiomers could be obtained using either Citrus reticulata or ruthenium complex. Chirality 27:205–210, 2015. © 2014 Wiley Periodicals, Inc.     

柑橘叶片和果皮总蛋白质提取及双向电泳体系的建立

以春甜橘(Citrus reticulata Blanco‘Chuntianju’)果皮和叶片为材料,分别用Tris-HCl、尿素/硫脲(Thi/Urea)、三氯乙酸/丙酮(TCA)和酚(Phe)等4种方法提取柑橘总蛋白质,从蛋白质产量、单向SDS-PAGE和双向电泳等方面进行比较。结果表明,4种方法的分离效果存在较大差异,不论是以柑橘叶片还是果皮为材料,均以TCA法最好,且双向电泳图谱分辨率较好,蛋白点清晰、均匀、基本没有条纹,且蛋白点多。这说明TCA法不仅能很好地去除柑橘果皮、叶片中存在的大量干扰物质,而且还能得到稳定的蛋白点。     

Evaluation of an organic treatment for post-harvest control of crown rot of banana

An organic treatment for control of crown rot disease of banana was developed and evaluated at EARTH University in Costa Rica. Studies were conducted to evaluate the efficacy of Biocto 6 (seed extract from citrus) in combination with the wax-based adjuvant Verdiol for control of post-harvest crown rot of banana. The standard commercial fungicide treatment (thiabendazol, imazalil and ammonium sulfate) and an untreated control were included for comparison. Bananas with the various treatments were processed using standard commercial procedures and stored in a refrigerated chamber that was modified to simulate commercial transport, distribution and controlled ripening for exported bananas. Fruit clusters were evaluated for percent weight loss, ripening in storage and crown rot disease severity. At the end of the 28-day storage period, there were no significant differences in percent weight loss between any of the treatments. There was no significant difference in ripening (maturity level) between the organic treatment and the commercial fungicide standard in 2 years of testing. In 2003, the untreated control had a significantly higher maturity rating than the organic or standard fungicide treatment. However, there were no significant differences in any of the treatments in maturity level in 2005. There was no significant difference between the organic and standard fungicide treatment for crown rot control and both treatments had significantly less crown rot than the untreated control. Results indicate that Biocto 6 in combination with Verdiol wax provides a new organic alternative for control of post-harvest crown rot of banana.     

琯溪蜜柚汁胞在发育与粒化过程中APX活性变化及其同工酶分析

对不同发育时期的琯溪蜜柚(Citrus grandis'Guanximiyou')汁胞进行APX活性测定及同工酶分析.结果表明,随着汁胞的发育,APX活性增大;而柚子衰老腐烂时,APX活性迅速降低.APX同工酶随着汁胞发育而发生变化,花后150 d的APX同工酶增加了1个组分(迁移率0.66),且随着汁胞的成熟,其表达量增加.花后230 d时柚子开始衰老腐烂,花后242 d已难以看到大部分APX同工酶酶谱.粒化汁胞的APX活性比正常汁胞大,同工酶酶谱亮度和清晰度也大,推测琯溪蜜柚汁胞在粒化过程中APX可清除活性氧61由基,抵抗氧化损伤.     

分子标记鉴定常山胡柚优良基因型的初步研究

本研究利用RAPD和ISSR分子标记对常山胡柚的优良基因型进行鉴定,并探讨常山胡柚的起源。从100个RAPD引物中筛选出12个多态性引物用于正式扩增,共得到117条DNA带,其中多态性DNA带64条,占扩增片段的54．7%;从105个ISSR引物中筛选出11个多态性引物用于正式扩增,共得到94条DNA带,其中多态性DNA带58条,占扩增片段的61．7%。RAPD和ISSR分析揭示了常山胡柚及其近缘种的一些特异性条带。ISSR共产生了15条特异条带,RAPD共产生12特异性条带。实验数据用AMOVA软件计算遗传距离,用NTSYS-pc软件构建UPGMA聚类树状图。结果显示,所有的基因型及不同种之间均能够彼此区分,分析得到的指纹图谱对常山胡柚种和基因型的鉴定具有潜在的应用价值,可用于优良基因型的鉴定。聚类分析结果显示常山胡柚和甜柚聚为一枝,确定了甜柚是杂交亲本之一,但是常山胡柚和柚的遗传距离较远,说明常山胡柚可能是甜橙、柚和柑桔属其他种的多重自然杂交的结果。     

柑桔种间体配融合及培养研究

“平户”文旦（柚）（Ｃｉｔｒｕｓｇｒａｎｄｉｓ）Ｏｓｂｅｃｋ的四分体经酶解,分离出原生质体。ＰＥＧ（聚乙二醇）诱导这类原生质体与二倍体“伏令夏”甜橙（Ｃ．ｓｉｎｅｎｓｉｓ）胚性悬浮细胞系的原生质体融合。融合后的原生质体培养于ＢＨ３／ＥＭＥ培养基中。２天后,观察到花粉管生长现象。不同处理的结果显示,这一现象来源于异核体细胞。这种具花粉管生长的细胞可进一步分裂,形成多细胞团及球形和心形胚状体。对再生的胚状体进行染色体数检查,证明１３．１％的胚状体为三倍体,２ｎ＝３ｘ＝２７。而起始悬浮细胞系为二倍体,检查的３９２个细胞,未发现有染色体倍性变异。     

Pectin methyl esterase from orange fruit: characterization and localization by in-situ hybridization and immunohistochemistry

Pectin methyl esterase (PME) from orange (Citrus sinensis L.) fruit peels has been purified by ammonium sulphate precipitation, and ion-exchange and gel-filtration chromatography. Characterization of the enzyme revealed a 36-kDa protein with an isoelectric point >9, a pH optimum at 7 and temperature optimum at 50 °C. The substrate specificity and kinetic experiments showed that the affinity of PME for pectin was highly dependent on the degree of esterification (DE) of the pectin, with K _m values of 0.7 mg ml^-1 for pectin with a DE of 70% and 17 mg ml^-1 for pectin with a DE of 25%. The sequences of the NH₂-terminal end of digested peptides from the mature protein were obtained. A DNA fragment of 501 bp was cloned by polymerase chain reaction amplification using degenerate primers and was further used for screening of a cDNA library. Two cDNA clones were isolated encoding PMEs of 584 amino acids and 362 amino acids, respectively, including a putative signal peptide. The deduced amino acid sequence showed full identity to the sequenced peptides. Polyclonal antibodies raised against orange peel PME were used for immunohistochemistry. The main localization of PMEs was in the outer cell layers of the juice vesicles, in the outer cell layers of the lamellae between the segments and in the inner cell layers of the albedo in the peel. In-situ hybridization showed that the mRNA is very abundant in the fruit and was found in the same cell layers as the native enzyme. A very intensive staining for PME mRNA was also seen in the core and in the flavedo close to the oil glands. Received: 15 November 1997 / Accepted: 7 April 1998     

Nitrogen fertilization in citrus orchards

Summary The purpose of this review was to evaluate critically the results obtained in citrus nitrogen fertilization experiments in Israel and in other parts of the world, in order to increase our understanding of the processes involved and to improve the recommendations to growers. Mature citrus trees contain 1–2 kg N/tree, 30–60% of which is in the annual parts (leaves and fruits). 30g N is deposited annually in the tree skeleton. Based on these results and on a review of long-term fertilization experiments with citrus from various parts of the world, it was concluded that 200 kg N/ha applied annually is sufficient to sustain good citrus yields and tree development, about half of which is incorporated in the fruits and one-tenth deposited in the tree, the balance being made up by leaching and gaseous losses. Experiments with¹⁵N labeled fertilizer applications showed that the highest N-uptake rate occurred during fruit set and that in winter the uptake was very low. N reserves in the older tissues played an important part in the development of new leaves and flowers in the spring, when the uptake from the soil was still low. It was concluded that the nitrogen contained in the soil organic matter (2 Mg/ha) and in the mature trees (1 Mg/ha) plays an important part in the regulation of N supply to the growing parts of the tree. More N is derived from these parts with low N fertilization than with an abundant supply. The purpose of fertilization is to ensure proper development of the tree, not the current fruit yield. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 1770-E. 1986 series.