Transgenic Expression of the Recombinant Phytase in Rice （Oryza sativa）

In many plants, phytic acid (phytate, 1, 2, 3, 4, 5, 6-hexakisphosphate) is one of the main storage forms of phosphate. About 80% of phosphorus (P) in cereal plants, including rice is stored as phytic acid [1-2]. P in phytic acid can’t be utilized by monogastric animals including human, while it was estimated that only 1/3 of the total P in most of the vegetal feedstuff could be efficiently utilized by the livestock. Therefore, for animal feed with P supplementation is expected to meet the d…     

Optimal Cleavage and Oxidative Folding of α-Conotoxin TxIB as a Therapeutic Candidate Peptide

Alpha6beta2 nicotinic acetylcholine receptors (nAChRs) are potential therapeutic targets for the treatment of several neuropsychiatric diseases, including addiction and Parkinson’s disease. Alpha-conotoxin (α-CTx) TxIB is a uniquely selective ligand, which blocks α6/α3β2β3 nAChRs only, but does not block the other subtypes. Therefore, α-CTx TxIB is a valuable therapeutic candidate peptide. Synthesizing enough α-CTx TxIB with high yield production is required for conducting wide-range testing of its potential medicinal applications. The current study optimized the cleavage of synthesized α-CTx TxIB resin-bounded peptide and folding of the cleaved linear peptide. Key parameters influencing cleavage and oxidative folding of α-CTx TxIB were examined, such as buffer, redox agents, pH, salt, co-solvent and temperature. Twelve conditions were used for cleavage optimization. Fifty-four kinds of one-step oxidative solution were used to assess their effects on each α-CTx TxIB isomers’ yield. The result indicated that co-solvent choices were particularly important. Completely oxidative folding of globular isomer was achieved when the NH₄HCO₃ or Tris-HCl folding buffer at 4 °C contained 40% of co-solvent DMSO, and GSH:GSSG (2:1) or GSH only with pH 8~8.7.     

Structural and Functional Characterization of a Novel α-Conotoxin Mr1.7 from Conus marmoreus Targeting Neuronal nAChR α3β2, α9α10 and α6/α3β2β3 Subtypes

In the present study, we synthesized and, structurally and functionally characterized a novel α4/7-conotoxin Mr1.7 (PECCTHPACHVSHPELC-NH₂), which was previously identified by cDNA libraries from Conus marmoreus in our lab. The NMR solution structure showed that Mr1.7 contained a 3₁₀-helix from residues Pro⁷ to His¹⁰ and a type I β-turn from residues Pro¹⁴ to Cys¹⁷. Electrophysiological results showed that Mr1.7 selectively inhibited the α3β2, α9α10 and α6/α3β2β3 neuronal nicotinic acetylcholine receptors (nAChRs) with an IC₅₀ of 53.1 nM, 185.7 nM and 284.2 nM, respectively, but showed no inhibitory activity on other nAChR subtypes. Further structure-activity studies of Mr1.7 demonstrated that the PE residues at the N-terminal sequence of Mr1.7 were important for modulating its selectivity, and the replacement of Glu² by Ala resulted in a significant increase in potency and selectivity to the α3β2 nAChR. Furthermore, the substitution of Ser¹² with Asn in the loop2 significantly increased the binding of Mr1.7 to α3β2, α3β4, α2β4 and α7 nAChR subtypes. Taken together, this work expanded our knowledge of selectivity and provided a new way to improve the potency and selectivity of inhibitors for nAChR subtypes.     

Content of starch and sugars and in vitro digestion of starch by α-amylase in five minor millets

Five varieties of minor millets were studied for their amylose, soluble amylose, amylopectin, soluble amylopectin, reducing sugar, total sugar and starch contents. Pure starch was isolated from each variety and the enzymic degradation of starch by porcine pancreatic -amylase were examined with and without gelatinisation. Gelatinised sample ofEchinochloa frumentacea (var. K2) showed minimal hydrolysis and gelatinised sample ofPanicum miliaceum (var. CO3) showed maximum hydrolysis of starch by porcine pancreatic -amylase. Gelatinised starch was highly susceptible to enzymic digestion when compared to ungelatinised starch. The extent of starch degradation varied from 71 to 85 percent in gelatinised samples and starch degradation in ungelatinised sample varied from 10 to 18 percent.     

Characterization and Fine Mapping of Non-panicle Mutant （nop） in Rice

A mutant of panicle differentiation in rice called non-panicle (nop) was discovered in the progeny of a cross between 93-11 and Nipponbare. The mutant exhibits normal plant morphology but has apparently few tillers. The most striking change in nop is that its panicle differentiation is blocked, with masses of fluffy bract nodes generate from the positions where rachis branches normally develop in wild-type plants. Genetic analysis suggests that nop is controlled by a single recessive gene, which is temporarily named Nop(t). Based on its mutant phenotype, Nop(t) represents a key gene controlling the initiation of inflorescence differentiation. By using simple sequence repeat markers and sequence tagged site markers, Nop(t) gene was fine mapped in a 102-kb interval on the long arm of chromosome 6. These results will facilitate the positional cloning and functional studies of the gene.     

Molecular Cloning and Characterization of Citrate Synthase Gene in Rice （ Oryza sativa）

The full-length OsCS encoding citrate synthase was isolated from rice （Oryza sativa L. subsp, japonica）, OsCS is 1477-bp long and encodes a 474 amino acid polypeptide, Its putative protein sequence is highly identical to Daucus carota, Nicotiana tabacum Beta vulgaris subsp., Arabidopsis thaliana, and Citrus junos （〉70%）. The deduced amino-terminal sequence of OsCS showes characteristics of mitochondrial targeting signal. Southern blot analysis using ORF of the OsCS as the probe indicated that this gene exists in multiple copies in rice genome. The band with predicated size of 82 kD was detected by Western blot after being induced by 0,4 mmol/L IPTG.     

Pre-maturity α-amylase in wheat: The role of abscisic acid and gibberellins

The occurrence of pre-maturity α-amylase (PMA) is a major cause of poor bread-making quality (low Hagberg Falling Number) in wheat grain. In susceptible genotypes, it involves the excessive accumulation of high isoelectric point (pI) α-amylase in mature grain prior to germination and in the absence of pre-harvest sprouting. Several factors regulate PMA formation in developing grain, including genotype, agronomy, and environmental conditions. In particular, a cold period during mid-grain development has been found to be a major stimulus for PMA induction. Although the factors affecting the PMA occurrence are well known, little is known about the molecular mechanism governing its induction. The plant hormones abscisic acid (ABA) and gibberellins (GAs) influence various aspects of grain development, and it has been suggested that PMA involves changes in the amount of these hormones or the sensitivity of the grain to these hormones. This review summarizes recent studies investigating the role of ABA and GAs in PMA induction and PMA occurrence.     

The role of sensitivity to abscisic acid and gibberellin in pre-maturity α-amylase formation in wheat grains

To study the role of abscisic acid (ABA) and gibberellin (GA) sensitivity in regulating pre-maturity α-amylase (PMA) in wheat grains, plants were grown in a glasshouse under cold-shock and ambient conditions. α-amylase activity in response to applied ABA and GA was measured in detached-grains with the embryo removed (in vitro) and in intact-grains attached to the plant (in situ). The in vitro experiment was conducted using Spark (low PMA-susceptible genotype) and Rialto (highly PMA-susceptible genotype), with the aim of defining the time point for GA-sensitivity. The results showed an increase in GA-sensitivity at about 640 degree days after anthesis (DAA) in Rialto. There was no evidence for a change in ABA-sensitivity in either variety. The in situ experiments were conducted using genotypes from a Spark × Rialto doubled haploid population segregating for the Rht-D1a (tall) or Rht-D1b allele and for the presence or absence of 1BS/1RS. For Rht-D1a (tall) or Rht-D1b genotypes with or without 1BS/1RS, the cold-shock significantly increased GA-sensitivity, whereas there was no significant change in ABA-sensitivity. These results show PMA is related to an increase in GA-sensitivity that occurs in the aleurone at around 640 degree DAA, and can be enhanced by environmental factors (e.g. cold-shock).     

The role of sensitivity to abscisic acid and gibberellin in pre-maturity α-amylase formation in wheat grains

To study the role of abscisic acid (ABA) and gibberellin (GA) sensitivity in regulating pre-maturity α-amylase (PMA) in wheat grains, plants were grown in a glasshouse under cold-shock and ambient conditions. α-amylase activity in response to applied ABA and GA was measured in detached-grains with the embryo removed (in vitro) and in intact-grains attached to the plant (in situ). The in vitro experiment was conducted using Spark (low PMA-susceptible genotype) and Rialto (highly PMA-susceptible genotype), with the aim of defining the time point for GA-sensitivity. The results showed an increase in GA-sensitivity at about 640 degree days after anthesis (DAA) in Rialto. There was no evidence for a change in ABA-sensitivity in either variety. The in situ experiments were conducted using genotypes from a Spark × Rialto doubled haploid population segregating for the Rht-D1a (tall) or Rht-D1b allele and for the presence or absence of 1BS/1RS. For Rht-D1a (tall) or Rht-D1b genotypes with or without 1BS/1RS, the cold-shock significantly increased GA-sensitivity, whereas there was no significant change in ABA-sensitivity. These results show PMA is related to an increase in GA-sensitivity that occurs in the aleurone at around 640 degree DAA, and can be enhanced by environmental factors (e.g. cold-shock).     

Germination of Wheat Grains at Various Temperatures in Relation to the Activities of α-Amylase and Endoprotease

Abstract

Germination percentages of wheat grains sampled at 3 grain-filling stages : yellow-ripe stage (water content 45-50%), dough-ripe stage (35-40%), and full-ripe stage (25-30%), and imbibed in water at 12°C and 20°C were examined in relation to the activities of α-amylase and endoprotease. Wheat varieties studied were Chihoku-komugi, which is susceptible to pre-harvest sprouting, and Satanta, which is resistant. Germination percentage was higher at 12°C than at 20°C in all grains sampled at all stages in both varieties, and was higher in Chihoku-komugi than in Satanta at 20°C. The activity of α-amylase in the grains at the yellow-ripe stage was higher at 12°C than at 20°C in both varieties, but that at the other 2 stages was higher only in Satanta. Endoprotease increased rapidly from 7 to 10 days after the start of imbibition, and exceeded 12 units only at 12°C in Chihoku-komugi grains at the dough and full-ripe stages. The results showed that α-amylase activity was lower than the value equivalent to 300 brabender unit (BU) in amylography when the germination percentage was 0%. Endoprotease activity exceeded 6 units when the germination percentage exceeded 90%.     

Preparation,Evaluation and Characterization of Rutin–Chitooligosaccharide Complex

Plant Foods for Human Nutrition - Rutin possesses a wide range of application prospects with various bioactivities. However, its bitter and water-insoluble properties restrict its application in...     

Expression activity of the CpTI gene in transgenic rice plants

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Characterization of O-β-glucosidase Activity in Vanilla planifolia and the change during the Curing Crocess of Vanilla Beans

香草兰是最重要的食品香料之一,其主要香味成分为香兰素,主要存在于香草兰豆荚中.香兰素一般由成熟豆荚中的香兰素葡萄糖苷经过漫长的发酵过程转化而来.O-β-葡萄糖苷酶在发酵生香的过程中起着关键作用.研究结果表明:香草兰的根、茎、叶和豆荚中都具有O-β-糖苷酶活性,豆荚活性最高,叶片活性最低;来自不同器官的O-β-糖苷酶的底物特异性一致,都能降解香兰素糖苷、2-NPG、4-NPG,都不能降解n-OG及硫代葡萄糖苷;香草兰糖苷酶提取物在50～60℃处理1 min,对酶活性影响很小,70℃处理1 min,酶活性丧失约40％,说明香草兰糖苷酶对高温具有一定耐受性,杀青后剩余糖苷酶活性在漫长的发酵过程中能够满足酶促反应的需求.     

Expression of a barley ABA-responsive protein gene in transgenic rice

A cDNA clone encoding an ABA-responsive protein HVA1, was isolated by differential screening from barley aleurone layers (Hong et al.), Expression of the HVA1 gene is shown to be developmentally regulated, organ specif ic, and ABA and stress-induced (Hong et al.). Transgenlc tobacco plants constitutively expressing HVA1 protein displayed a 4-day delay of leave wilting under drought conditions and a lower water content threshcdd (39% vs 47.6%) at the time point of first wilting. These data indicate that HVA1 protein may play a role in plant tolerance to drought     

Inhibition of Ultraviolet B-Induced Expression of the Proinflammatory Cytokines TNF-α and VEGF in the Cornea by Fucoxanthin Treatment in a Rat Model

Ultraviolet B (UVB) irradiation is the most common cause of radiation damage to the eyeball and is a risk factor for human corneal damage. We determined the protective effect of fucoxanthin, which is a carotenoid found in common edible seaweed, on ocular tissues against oxidative UVB-induced corneal injury. The experimental rats were intravenously injected with fucoxanthin at doses of 0.5, 5 mg/kg body weight/day or with a vehicle before UVB irradiation. Lissamine green for corneal surface staining showed that UVB irradiation caused serious damage on the corneal surface, including severe epithelial exfoliation and deteriorated epithelial smoothness. Histopathological lesion examination revealed that levels of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α) and vascular endothelial growth factor (VEGF), significantly increased. However, pretreatment with fucoxanthin inhibited UVB radiation-induced corneal disorders including evident preservation of corneal surface smoothness, downregulation of proinflammatory cytokine expression, and decrease of infiltrated polymorphonuclear leukocytes from UVB-induced damage. Moreover, significant preservation of the epithelial integrity and inhibition of stromal swelling were also observed after UVB irradiation in fucoxanthin-treated groups. Pretreatment with fucoxanthin may protect against UVB radiation-induced corneal disorders by inhibiting expression of proinflammatory factors, TNF-α, and VEGF and by blocking polymorphonuclear leukocyte infiltration.     

Facilitation of α-polylysine in TGase-mediated crosslinking modification for gluten and its effect on properties of gluten films

In this study, α-polylysine was used to enhance the cross-linking effect of TGase on gluten and its effects on properties of gluten films were investigated. The amount of free ammonia released from the cross-linking reaction of gluten induced by TGase at the presence of α-polylysine obviously increased, and more polymers with higher molecular weight were formed from the SDS-PAGE results, which indicated that the TGase-mediated cross-linking reaction ability of gluten was strengthened with the incorporation of α-polylysine. The tensile strength of the films from gluten modified with TGase (20 units/g wheat gluten) and 2% α-polylysine (g/g gluten) for 3 h increased from 4.02 ± 0.09 MPa to 5.28 ± 0.14 MPa, which was more effective than that treated with TGase alone (in which the tensile strength of the films was 4.49 ± 0.10 MPa). The TGase treatment with α-polylysine of gluten improved the water stability of the films much more than that treated with TGase alone. A rougher surface and a more compact cross-section structure were observed by SEM for the films from TGase-α-polylysine treated gluten. The contact angles between the gluten films surface and a water droplet increased because of TGase-mediated cross-linking modification.     

The location of disulphide bonds in α-type gliadins

Gliadin prepared from gluten of the cultivar Rektor by extraction with 70% (v/v) aqueous ethanol adjusted to pH 5.5 was separated by RP-HPLC. Amongst 23 components obtained, two α-type gliadins (α3- and α8-gliadin) were selected for the determination of disulphide bonds. After both proteins were digested with thermolysin, differential RP-HPLC (chromatography prior to and after reduction of disulphide bonds) was used for the detection of cystine peptides. Two cystine peptides from α3-gliadin and three cystine peptides from α8-gliadin were isolated by RP-HPLC. The resulting peptides were reduced and alkylated with 4-vinylpyridine, separated by RP-HPLC and their amino acid sequences determined. The cystine peptides from both α-type gliadins had similar structures, and the corresponding fragments had homologous sequences. One cystine peptide of each gliadin was composed of three fragments linked by two disulphide bonds. The second cystine peptide consisted of two fragments linked by one disulphide bond. The third cystine peptide derived from α8-gliadin was different from the second peptide in one position of the sequences (glutamic acid instead of glutamine). Comparing complete sequences of α-type gliadins described in the literature, the cystine peptides from α3- and α8-gliadins were identical with corresponding sequences of clones A1235 and A212, respectively¹¹. The structures of the cystine peptides analysed indicate one intramolecular disulphide bond within domain III of α-type gliadins and two disulphide bonds between domains III and V. The linkages found correspond to homologous linkages determined for low M_r subunits of glutenin and glutenin-bound γ-type gliadins⁶. Obviously, these intramolecular disulphide bonds are not linked randomly, but are strongly directed.     

Expression of indica rice resistant sources to Brown planthopper（BPH） in indica-japonica hybrids and their utillzation

We studied the genetic mode in transferring BPH-resistance genes from indica varieties to japonica varieties January 1988 to December 1989 in Nanjing, Jiangsu Province. Indica varieties selected on a basis of BPH-resistance genes, i.e., Yankeng 2 (japonica), 02428 (japonica), 40316 (indica-japonica progeny),