Cell wall metabolism in gibberellin-treated persimmon fruits

The application of gibberellin [GA₃] to persimmon fruits as an orchard spray, at least 2 weeks prior to harvest, has been shown to delay ripening of the fruit on the tree and its rate of softening after harvest. This effect persisted during and after cold storage. The delay in softening has been attributed to the effect of the phytohormone on cell wall metabolism. To examine this hypothesis, cell walls of GA₃-treated fruit were compared to those of non-treated fruit. Comparison between fruit was from harvest till the termination of post-storage softening. The study included TEM examinations, assay of certain hydrolase activities and determination of compositional changes occurring in the various cell-wall carbohydrate polymers. Our findings indicate that GA₃ either delays or inhibits all of the cell wall changes that were found to accompany fruit softening, including dissolution of the middle lamella, separation of the plasmalemma from the cell-wall, mitigation of the structural coherence and density of the primary cell wall, increases solubilization of pectic polymers, loss of neutral sugars, predominantly arabinose and galactose, and increased activities of exo-polygalacturonase [PG] and endo-1,4--glucanase [EGase]. The principal discernible compositional difference between GA₃-treated fruit and control fruit at harvest was a higher total carbohydrate content in the cell wall material extracted from GA₃-treated fruit, which was due chiefly to an increased amount of cellulose.     

广西柿种质资源果实性状多样性分析与模糊综合评价

为进一步揭示广西柿种质资源信息,运用多样性分析和模糊综合评价法对不同生态气候区的柿种质资源果实性状进行研究和评价。结果表明:不同柿种质的果实性状存在丰富的多样性。86份柿种质的模糊综合评价指数FCI值在1.849～3.947之间,平均2.835。根据FCI取值范围将所调查的柿种质分成5个等级,FCI值最高的第5级种质数量最少,占所调查种质的3.49%;FCI值最低的第1级种质数量最多,占所调查种质的48.84%。月柿、牛心柿、大方柿、京柿、鸡心柿、小方柿和火柿等柿品种及一些实生单株的模糊综合评价指数较高,它们的果实综合性状表现较优,建议作为优良品种和单株加以开发和利用。部分单个性状比较优良的实生单株虽不适合于直接推广种植,但可作为柿品种改良的资源加以利用。     

Expressed sequence tags from stem tissue of the American chestnut, Castanea dentata

Subtracted and size-selected unsubtracted cDNA libraries were created to examine gene expression in the woody tissues of Castanea dentata. A total of 50 clones were sequenced and comparisons were made to the GenBank database. Expression analysis of 20 selected clones revealed that 13 were expressed predominantly in the stem and leaf tissues, while the other seven were present in all tissues examined.     

Analysis of expressed sequence tags from biodiesel plant Jatropha curcas embryos at different developmental stages

Jatropha curcas is considered a potential biodiesel feedstock plant whose seeds contain up to 40% oil. However, little is currently known about the seed biology of Jatropha. Therefore, it would be valuable to understand the mechanisms of development and lipid metabolism in Jatropha seeds. In the present study, three cDNA libraries were constructed with mRNA from Jatropha embryos at different stages of seed development. A total of 9844 expressed sequence tags (ESTs) were produced from these libraries, from which 1070 contigs and 3595 singletons were obtained. One hundred and seven unigenes were found to be differentially expressed in the three cDNA libraries of Jatropha embryos, indicating that these genes may play key roles in seed development. We have identified 59 and 61 unigenes that might be involved in the development and lipid metabolism in Jatropha seeds, respectively. Some of these genes may also play important roles in embryogenesis, morphogenesis, defense response and adaptive mechanisms in plants.     

Strapping and a synthetic cytokinin promote cell enlargement in ‘Hiratanenashi’ Japanese persimmon

The effects of N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) with and without strapping on fruit growth of ‘Hiratanenashi’ Japanese persimmon were evaluated by measuring parenchyma cell size and the number of cell layers in mesocarp throughout fruit development. Three-year-old branches were strapped with a wire 2 weeks before full bloom, and 10 mg l⁻¹ of CPPU was applied to the fruitlet at 10 days after full bloom. CPPU alone prolonged the growth period, resulting in a larger fruit diameter at harvest than the control. Strapping promoted the fruit coloration and increased final fruit diameter. CPPU plus strapping shortened the growth period compared to CPPU alone, and the mature fruit diameter was similar to CPPU alone. The increases in fruit diameter caused by CPPU and strapping were involved with the increases in length of parenchyma cell. The number of cell layers was almost similar among the treatments. These results showed that strapping promotes the rate of parenchyma cell expansion, and CPPU with and without strapping prolong the duration of cell enlargement and promote the rate of the cell expansion.     

Carbon assimilation by different developmental stages of Laminaria saccharina

Various stages of the life cycle of the marine brown alga Laminaria saccharina (L.) Lamour. (Laminariales, Phaeophyta) including male and female gametophytes, female gametes, zygotes and young sporophytes of different age were investigated for their potentials of carbon dioxide (¹⁴CO₂) fixation. Rates of photosynthesis attain the same order of magnitude in all stages. Photosynthetic ¹⁴CO₂-fixation is accompanied by a substantial light independent carbon assimilation. This is confirmed by rate determinations of the equivalent carboxylating enzymes present in the plants, ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39) and phosphoenolpyruvate carboxokinase (EC 4.1.1.32) as well as by chromatographic analyses of the appropriate [¹⁴C]-assimilate patterns.Abbreviations RuBP-C ribulose-1,5-bisphosphate carboxylase - PEP-CK phosphoenolpyruvate carboxykinase - PEP phosphoenolpyruvate - PS photosynthesis - DF dark fixation     

A comparison of sequence complexity of nuclear and polysomal poly(A)+ RNA from different developmental stages ofXenopus laevis

Summary Nuclear poly(A)⁺ and polysomal poly(A)⁺ RNA were isolated from gastrula and early tadpole stages of the amphibianXenopus laevis. Complementary DNA was synthesized from all RNA preparations. Hybridization reactions revealed that at least all abundant and probably most of the less frequent nuclear and polysomal poly(A)⁺ RNA species present at the gastrula stage are also present at the early tadpole stage. On the other hand, there are nuclear RNA sequences at the latter stage which appear, if at all, only at lower concentrations at the gastrula stage. The polysomal poly(A)⁺ RNA hybridization reactions suggest the existence of polysomal poly(A)⁺ RNA sequences at early tadpole stages which are not present in the corresponding gastrula stage RNA.By cDNA hybridization with poly(A)^– RNA it could be shown that most of the poly(A)⁺ containing RNA sequences transcribed into cDNA were also present within the poly(A)^– RNA. It was estimated, that these sequences are 10 fold more abundant within the poly(A)^– polysomal RNA and 3–6 more abundant within the poly(A)^– nuclear RNA as compared to the poly(A)⁺ RNAs.     

Cell wall composition in the ascomycete sphaerostilbe repens at different developmental stages

Changes in the biochemical composition of isolated cell walls were analysed during the differentiation of coremia and rhizomorphs in Sphaerostilbe repens.Differentiation was accompanied by exclusively quantitative variations of the wall components: the content in carbohydrates, chitin and free amino sugars increased; on the contrary, amino acids, uronic acids, lipids and mineral substances decreased.Carbohydrates were composed of glucose, galactose and mannose; glucosamine was the main component of amino sugars. The predominant amino acid in the walls was cysteine the amount of which increased during hyphal aggregation, while quantities of the sixteen other determined amino acids decreased.Mineral matter was present in large quantities in the walls of the fungus, especially in vegetative mycelium. Iron, phosphorus and calcium were the most abundant elements.Possible relations between the variations in chemical composition of the wall and the capability of hyphae to aggregate are discussed.     

广叶绣球菌不同生长阶段栽培基质中代谢物差异分析

【背景】栽培基质的利用是广叶绣球菌(Sparassis latifolia)栽培中重要的生理过程，但栽培过程中基质代谢物的变化尚不清楚。【目的】通过不同生长阶段栽培基质中差异代谢物分析挖掘关键代谢物，为广叶绣球菌基质利用机理研究提供理论参考。【方法】利用UHPLC-MS/MS技术分析广叶绣球菌菌丝(Myc)、原基(Pri)和子实体(FB)生长阶段栽培基质中代谢产物的变化，通过不同数据库进行代谢物注释并进行KEGG通路富集分析。利用LC-MS/MS技术检测不同发育阶段绣球菌中植物类激素含量。【结果】三个不同栽培阶段基质中共鉴定出代谢产物1 360个。不同比较组(Pri vs. Myc、FB vs. Myc和FB vs. Pri)间共有的差异代谢产物179个，含量最高的50个代谢物主要包括氨基酸、脂质、吡喃酸、吡喃酮和植物类激素等物质。其中氨基酸含量在Myc、Pri和FB阶段基质中逐渐降低，而吡喃酸和吡喃酮类化合物含量逐渐升高。植物类激素中的赤霉素在Pri和FB阶段基质中含量较高，茉莉酸在Myc阶段基质中含量较高。对不同发育阶段绣球菌植物类激素进行检测，发现赤霉素GA7仅在原基中检测到，1...     

Expressed sequence tags from the red imported fire ant, Solenopsis invicta: annotation and utilization for discovery of viruses

An expression library was created and 2304 clones sequenced from a monogyne colony of Solenopsis invicta. The primary intention of the project was to utilize homologous gene identification to facilitate discovery of viruses infecting this ant pest that could potentially be used in pest management. Additional genes were identified from the ant host and associated pathogens that serve as an important resource for studying these organisms. After assembly and removal of mitochondrial and poor quality sequences, 1054 unique sequences were yielded and deposited into the GenBank database under Accession Nos. EH412746 through EH413799. At least nine expressed sequence tags (ESTs) were identified as possessing microsatellite motifs and 15 ESTs exhibited significant homology with microsporidian genes. These sequences most likely originated from Thelohania solenopsae, a well-characterized microsporidian that infects S. invicta. Six ESTs exhibited significant homology with single-stranded RNA viruses (3B4, 3F6, 11F1, 12G12, 14D5, and 24C10). Subsequent analysis of these putative viral ESTs revealed that 3B4 was most likely a ribosomal gene of S. invicta, 11F1 was a single-stranded RNA (ssRNA) virus contaminant introduced into the colony from the cricket food source, 12G12 appeared to be a plant-infecting tenuivirus also introduced into the colony as a field contaminant, and 3F6, 14D5, and 24C10 were all from a unique ssRNA virus found to infect S. invicta. The sequencing project illustrates the utility of this method for discovery of viruses and pathogens that may otherwise go undiscovered.     

A systematic study on hemocyte identification and plasma prophenoloxidase from Culex pipiens quinquefasciatus at different developmental stages

Culexpipiens quinquefasciatus (C. quinquefasciatus) is an important vector that can transmit human diseases such as West Nile virus, lymphatic filariasis, Japanese encephalitis and St. Louis encephalitis. However, very limited research concerning the humoral and cellular immune defenses of C. quinquefasciatus has been done. Here we present the research on hemocyte identification and plasma including hemocyte prophenoloxidase from C. quinquefasciatus at all developmental stages in order to obtain a complete picture of C. quinquefasciatus innate immunity. We identified hemocytes into four types: prohemocytes, oenocytoids, plasmatocytes and granulocytes. Prophenoloxidase (PPO) is an essential enzyme to induce melanization after encapsulation. PPO-positive hemocytes and plasma PPO were observed at all developmental stages. As for specific hemocyte types, prophenoloxidase was found in the plasmatocytes at larval stage alone and in the smallest prohemocytes during almost all developmental stages. Moreover, the granulocytes were PPO-positive from blood-fed female mosquitoes and oenocytoids were observed PPO-positive in pupae and in adult females after blood-feeding. As for plasma, there were different patterns of PPO in C. quinquefasciatus at different developmental stages. These results are forming a basis for further studies on the function of C. quinquefasciatus hemocytes and prophenoloxidase as well as their involvement in fighting against mosquito-borne pathogens.     

Analysis of expressed sequence tags (ESTs) from Lentinula edodes

The 1,031 expressed sequence tags (ESTs) from the basidiomycete Lentinula edodes were generated as a pilot experiment to see distribution of genes expressed in L. edodes. Among them, genes for hydrophobin, which are specifically found in filamentous fungi, were the most frequently obtained ESTs (33 times), suggesting that they are highly expressed in L. edodes. In addition to known hydrophobin 1 and 2 types, our analysis revealed the existence of novel types of hydrophobin, which we named hydrophobin 3, 4, and 5. The second and the third most highly obtained ESTs were phosphatidylserine decarboxylase and formate dehydrogenase, which were obtained eight and seven times, respectively. It should be noted that two important genes (argonaute and RNA-dependent RNA polymerase) involved in the RNAi pathway were found, suggesting a future application for gene knock-down by RNA interference. The 53 ESTs were identical with the sequences already reported in L. edodes. The 433 ESTs were found to show significant sequence similarity (E value <1 x 10(-5)) with the proteins reported (or predicted) in other species. In total, 387,952 bp were sequenced and registered in DDBJ/GenBank (accession number BJ998097-BJ999127).     

Expressed sequence tags of Trichinella spiralis muscle stage larvae

In order to obtain greater insight into the relevant genomic expression patterns of Trichinella spiralis, 992 expressed sequence tags (ESTs) were collected from a cDNA library of T. spiralis muscle stage larvae and assembled into 60 clusters and 385 singletons. Of them, 445 (44.7%) ESTs were annotated to their homologous genes, and small fractions were matched to known genes of nematodes. The annotated ESTs were classified into 25 eukaryotic orthologous groups (KOG). Cytochrome C oxidase (34 clones) was found to be most frequent species.