• Volume 36,Issue 3,2015 Table of Contents
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    • An investigation of resistance genes in bacteria from vegetables adjacent to the swine farms in Southern China

      2015, 36(3):1-7. DOI: 10.7671/j.issn.1001-411X.2015.03.001

      Abstract (1893) HTML (599) PDF 455.15 K (2258) Comment (0) Favorites

      Abstract:【Objective】This experiment was conducted to investigate the resistance genes in bacteria from vegetable samples adjacent to the swine farms in Southern China. 【Method】PCR and sequencing were performed to detect the resistance genes of aminoglycoside, tetracycline, beta lactamase, quinolone, macrolide and clindamycin. 【Result and conclusion】Tetracycline resistance genes had a wide distribution range (the ground detectable rate of this kind of gene was 90% (9/10) both in accessory bacteria and endophytic bacteria). There were different resistance genes between accessory bacteria and endophytic bacteria from vegetables, and accessory bacteria had richer resistance genes than endophytic bacteria. The detectable rates of resistance genes in accessory bacteria of A, B, C, D, E, F, G, H, I and J samples were 77.78% (21/27), 92.59% (25/27), 92.59%(25/27), 51.85% (14/27), 33.33% (9/27), 92.59% (25/27), 77.78% (21/27), 7.41% (2/27), 81.48% (22/27) and 77.78% (21/27), respectively; the detectable rates of resistance genes in endophytic bacteria were 0 (0/27), 11.11% (3/27), 11.11% (3/27), 11.11% (3/27), 29.63% (8/27), 48.15% (13/27), 29.63% (8/27), 33.33% (9/27), 25.93% (7/27) and 22.22% (6/27), respectively. The results indicate that the resistance problem in bacteria, especially accessory bacteria from vegetables, is probably very serious. It can even inhibit the growth of crops and threaten animal and human health through food chain to which enough importance should be attached.

    • Studies on the excretion of robenidine hydrochloride in rabbit urine and feces

      2015, 36(3):8-12. DOI: 10.7671/j.issn.1001-411X.2015.03.002

      Abstract (2189) HTML (536) PDF 1003.56 K (2512) Comment (0) Favorites

      Abstract:【Objective】In order to investigate the excretion quantitation of robenidine in rabbit urine and feces, a high performance liquid chromatography (HPLC) method was developed to detect the concentrations of robenidine hydrochloride. 【Method】Twelve healthy rabbits were administered robenidine hydrochloride orally with a dose of 15 mg·kg-1.After administration, all of their urine and feces were collected at different time intervals and mass were achieved. Feces 0.2 g was extracted using chloroform-methanol [V(chloroform)∶V (methanol)=2∶1]; urine 1 mL was extracted with φ=0.2% acidified ethyl acetate, and the organic phase was separated and evaporated. The residue was redissolved with acetonitrilewater [V (acetonitrile)∶V(water)=30∶70] solution, and cleaned up by solid-phase extraction using CNW HLB after being evaporated to dryness;the residue was redissolved in methanol,and then analyzed by HPLC. 【Result and conclusion】The results showed that the limit of detection (LOD) and the limit of quantitation (LOQ) of robenidine in urine were 0.005 and 0.01 μg·mL-1 respectively, with the proportion of the total administered robenidine being 0.56%; the LOD and the LOQ of robenidine in feces were 0.01 and 0.05 μg·g-1 respectively,with the proportion of the total administered robenidine being 87.17%.The excretion peak time of robenidine in urine and feces was 0-6 and 6-12 h respectively, and the total amount of accumulated excretion was 28.37% and 38.46% respectively after administration. The results indicate that this method can be used to detect the concentration of robenidine in rabbit urine and feces, and most of the administered drug is excreted in the original form of urine and feces.

    • Molecular cloning and sequence analyses of the complete genome of duck Tembusu virus isolated from the Pearl River Delta region

      2015, 36(3):13-19. DOI: 10.7671/j.issn.1001-411X.2015.03.003

      Abstract (1730) HTML (485) PDF 582.25 K (2541) Comment (0) Favorites

      Abstract:【Objective】In order to comprehend the molecular characteristics of duck Tembusu virus , the isolations of GDNS2010.1, GDNS2010.2, GDZQ2012, GDPY2013 in the Pearl River Delta region were analyzed.【Method】 From the reference strains (GenBank accession no.JS804), eleven pairs of specific primers were designed and synthesized to amplify genome sequence fragments of GDNS2010.1, GDNS2010.2, GDZQ2012, GDPY2013. The whole genome sequences of these four viruses were obtained.The complete genome sequences of four viruses were obtained by sequencing and splicing. 【Result and conclusion】 Analyses showed that the full length of these four viruses was 10 990 bp, no Ploy (A) tail structure comprising one large ORF, encoding 3 426 amino acids. The 5′ non-coding region (5′UTR) contained 94 bp. Ten bases were missing from 103 395 bp to 103 411 bp of GDNS2010.1 and GDNS2010.2 strains in the 3′ non-coding region (3′UTR). Two sequences of GDHZ2012.1 and GDHZ2012.2 preliminarily determined were joined for a sequence analysis. DNAstar and MEGA6.0 were used to analyze the sequences of six virus strains. Comparisons with other domestic Tembusu viruses recorded in GenBank showed that the similarity of the nucleic acid sequence was more than 98%. In comparison with Ntaya virus, Sitiawan virus, the similarity was about 73%. Compared with West Nile virus, Japanese encephalitis virus and yellow fever virus, the similarities were less than 63%. The similarity for nucleic acid sequence of envelope protein in the six isolates remained between 97.5%-99.9%; the similarity of deduced amino acid sequence was found to be more than 97% whereas isolates from the same area had 99.9% similarity. In the site of E154 in envelope, there are a potential glycosylation site Asn-Try-Ser and a potential virulence loci in E289.

    • Cloning surface protective antigen A gene from Erysipelothrix rhusiopathiae and its expression in Pichia pastoris

      2015, 36(3):20-25. DOI: 10.7671/j.issn.1001-411X.2015.03.004

      Abstract (1797) HTML (465) PDF 816.71 K (2562) Comment (0) Favorites

      Abstract:【Objective】Immunization protection area protein, which lies in the N-terminal protective domain of surface protective antigen A(SpaA) of Erysipelothrix rhusiopathiae, was expressed in Pichia pastoris X-33.【Method】 Using the swine erysipelas, which was isolated from a pig farm in Guangdong as template, a pair of primers was designed according to the cDNA sequence of Spa gene from NCBI.The amino terminal sequence was achieved by PCR amplification, after being inserted into the expression vector pPICZαC to get the recombinant plasmid of pPICZαC-SpaA-N. Recombinant plasmid of pPICZαC-SpaA-N by Sac I enzyme was linearized, and electro transformed it into P. pastoris X-33. The positive transformant,screened by YPDS tablet with ZencinTM and identified by PCR at different concentrations of ZencinTM, achieved the high number of copies which were induced and cultured by methanol. Supernatant was collected by centrifugation at 48, 72, 96 h respectively after induction, and SDS-PAGE and Western-blot tests were carried out.【Result and conclusion】 The SpaA gene was successfully cloned and expressed, and the recombinant plasmid of pPICZαC-SpaA-N was constructed. The immunization protection area protein, which lies in SpaA gene amino terminal of swine E. rhusiopathiae in P. pastoris X-33, was successfully expressed. SpaA gene of swine E. rhusiopathiae has been successfully expressed asimmunization protection area protein in yeast host, which will lay a foundation for the development and the mass production of subunit vaccine of swine E. rhusiopathiae.

    • The influence of soil moisture on plant growth and grain yield in no-tillage rice

      2015, 36(3):26-31. DOI: 10.7671/j.issn.1001-411X.2015.03.005

      Abstract (1673) HTML (384) PDF 445.05 K (2092) Comment (0) Favorites

      Abstract:【Objective】The effect of soil moisture on plant growth characteristic and grain yield of no-tillage rice was investigated to identify the optimal soil moisture for no-tillage rice production. 【Method】 Pot experiments were conducted in the early and late seasons of 2013. In each season, a hybrid rice cultivar Jiyou716 was cultivated under the saturated soil moistures of 95%-100% (W100), 80%-85% (W85) and 65%-70% (W70). 【Result and conclusion】 The grain yield, biomass and harvest index of no-tillage rice under W70 were significantly lower than those under W100 and W85. The reason why the grain yield decreased under W70 was that panicle became small and seed set decreased. The biomass and transportation under W70 were significantly inhibited. The tiller dynamic of no-tillage rice was divided into two stages, and the tiller number first increased and then decreased. The tiller number decreased when soil moisture reduced, and there were significant differences among the three treatments at peak tillering stage, but no significant differences in the end. The plant height decreased when soil moisture reduced, and there were significant differences among the three treatments. The area, length and width of three leaves from top decreased when soil moisture reduced at the elongation stage. The soil water deficiency first influence the leaf width, then the leaf length, and lead to the leaf area decrease in the end at the elongation stage. The area, length and width of three leaves from top under W70 significantly reduced at the heading stage. Therefore, the soil moisture should be not less than 70% of saturated soil moisture in no-tillage rice cultivation.

    • Effects of broadcasting density and seedling strengthen agent on physiological characteristics of rice seedling

      2015, 36(3):32-36. DOI: 10.7671/j.issn.1001-411X.2015.03.006

      Abstract (1741) HTML (474) PDF 417.48 K (2626) Comment (0) Favorites

      Abstract:【Objective】Effects of broadcasting density and seedling strengthen agent on physiological characteristics of rice seedling were studied.【Method】 By conventional dry nursery using an aromatic rice cultivar Nongxiang18 as material, four broadcasting densities,which were 30, 60, 90, 120 g·plate-1, respectively, were designed,and whether seedling strengthen agent was applied or not.【Result and conclusion】 The results showed that leaf area and rice seedling dry mass(leaf dry mass, stem dry mass, root dry mass and dry mass per height) significantly decreased with the increase of broadcasting density when broadcasting density was in the range of 30-120 g·plate-1.The values of leaf area and rice seedling dry mass (leaf dry mass, stem dry mass, root dry mass and dry mass per height) were higher in the broadcasting density of 30 g·plate-1 than those of other treatments whether seedling strengthen agent was applied or not. Compared with the treatment of no seedling strengthen agent, the seedling strengthen agent could increase SPAD value, leaf area, rice seedling dry mass (leaf dry mass, stem dry mass, root dry mass and dry mass per height) and specific leaf mass. And superficial area, average diameter and volume of roots remarkably increased. Furthermore, the activities of superoxide dismutase (SOD) and peroxidase (POD) of rice seedling significantly increased, too. However, the plant height and malondialdehyde (MDA) concentration of rice seedling remarkably decreased. Principal component analysis showed that stronger stem (heavier stem dry mass, bigger width of stem and dry mass per height) and bigger value of root to shoot and heavier leaf dry mass may be considered as better rice seedling qualities rapidly and accurately at the growth stage of rice seedling.

    • Studies on the rice quality and starch RVA profile characteristics of indica rice varieties with national high-quality

      2015, 36(3):37-44. DOI: 10.7671/j.issn.1001-411X.2015.03.007

      Abstract (1967) HTML (488) PDF 1001.70 K (4180) Comment (0) Favorites

      Abstract:【Objective】To understand the grain characteristics of indica rice varieties with national high-quality. 【Method】 Yuejingsimiao2 and other rice varieties were employed to study the grain qualities, including the milling quality, appearance quality, cooking quality, nutritional quality and starch RVA profile. 【Result and conclusion】 The indica rice varieties with national high-quality had advantages of high head rice, narrow grain shape, little white-belly, good transparency, moderate amylose content and long gel consistency. The difference of protein content was not obvious among these indica rice varieties with national high-quality, but the difference of fatty acid content was obvious. The rice varieties of Yuexiuzhan, Bataixiang1 and Yuejingsimiao2 had higher fatty acid contents. In general, the RVA profiles of indica rice varieties with national high-quality had higher breakdown and lower setback values, and their eating qualities were better than those of indica rice varieties with non-national quality. The breakdown and setback values of Yuejingsimiao2,which was an indica rice variety with good eating quality, met the recognized indicators of good eating quality. The amylose content and gel consistency were positively correlated with cool paste viscosity, breakdown and setback values. A RVA profile analysis, particularly combined the selecting of amylose content and gel consistency with the analysis of breakdown and setback values, is helpful to improve the accuracy and efficiency in rice quality breeding.

    • Effects of 15-day continuously shading treatment after flowering on grain yield, quality and aroma of aromatic rice

      2015, 36(3):45-48. DOI: 10.7671/j.issn.1001-411X.2015.03.008

      Abstract (2074) HTML (452) PDF 386.31 K (1699) Comment (0) Favorites

      Abstract:【Objective】To investigate the effects of 15-day continuously shading treatment after flowering on yield, quality and major aromatic compound 2-acetyl-1-pyrroline (2-AP).【Method】 Two conventional aromatic rice cultivars of Yuxiangyouzhan and Nongxiang18 were treated by 15-day continuously shading after flowering and natural light in the field. The yield,quality, 2-acetyl-1-pyrroline content and other indexes of aromatic rice were measured.【Result and conclusion】 The results showed that compared with natural light, the 15-day continuously shading treatment after flowering significantly increased the contents of 2-acetyl-1-pyrroline and protein in grains, and significantly decreased 1000-grain mass, seed setting rate and yield as well as head rice rate. Therefore,low-light stress plays a positive role in the aroma enhancement of aromatic rice but leads to a yield reduction. The effects of shading on other grain quality traits are different due to different varieties.

    • Studies on maize haploid inducing and chemical doubling monoploids

      2015, 36(3):49-53. DOI: 10.7671/j.issn.1001-411X.2015.03.009

      Abstract (2036) HTML (670) PDF 413.22 K (3351) Comment (0) Favorites

      Abstract:【Objective】To induce maize haploid and double monoploids.【Method】The F1 generation hybrids of high resistance head smut inbred line K88 and high sense of head smut inbred line G115 of North corn regional were chose as female parents, which hybridized with male parents of 5 haploid inducers (JS6-11 - JS6-15) conduct maize haploid inducing test. Colchicine was used as maize haploid artificial chromosome doubling agent. Four approaches (dipping root method and dipping bud method, dipping heart leaf method and acupuncturing growing point method) were taken to conduct maize haploid doubling test and each set 3 concentration gradients (0.2, 0.4, 0.6 mg·mL-1), using DMSO at volume fraction of 2%+glycerol solution 5% as auxiliary reagents.【Result and conclusion】 Filament lengths and the time of pollination had significant effects on the haploid induction. The haploid induced rate of longer silk (≥7 cm) pollination was 17.0% on average, almost 3.3 times higher than that of shorter silk (≤4 cm) pollination. Haploid induced rate of pollination was 18.4% on average after midsummer, almost 3.4 times higher than that in midsummer pollination. The results showed that late pollination and low temperature increased haploid inducing frequency. Maize haploid doubling tests showed that the plant survival rates of dipping root were lower than 50%. Acupuncturing growing point method at concentration of 0.6 mg·mL-1 and dipping heart leaf method at concentration of 0.4 mg·mL-1 with the fertility rate of plants 45.9% and 28.9%, respectively, with maturing rate of two methods, 15.2% and 11.1%, respectively. Acupuncturing growing point and dipping heart leaf methods are better options for chromosome doubling.

    • Effects of different levels of phosphorus availability on growth and phosphorus absorption of “Chinese Long” sequenced cucumber genotype

      2015, 36(3):54-58. DOI: 10.7671/j.issn.1001-411X.2015.03.010

      Abstract (1542) HTML (331) PDF 1.05 M (2293) Comment (0) Favorites

      Abstract:【Objective】To explore the responses of “Chinese long” sequenced cucumber genotype to different phosphorus (P) availability, and to screen an optimal low-P-treatment concentration for cucumber germplasms screening for P efficiency under a hydropoic condition. 【Method】 Hydroponic culture was used to test effects of different P availability on the growth and P absorption of “Chinese Long”. 【Result and conclusion】 The results showed that with the decrease in P availability, cucumber plants became shorter and smaller, and new leaves became smaller and old leaves became yellow. Severe P deficiency (10 and 1 μmol·L-1) significantly inhibited the cucumber plant growth, even resulting in abnormal fruits. Low P availability decreased the biomass and P uptake efficiency of “Chinese Long”, but increased its ratio of root to shoot, which preferably allocated carbonhydrate to root. Furthermore, under P deficiency, “Chinese Long” also formed finer roots with a small root diameter, thus increasing the contact area with nutrients in the growth medium. The P concentration of 10-100 μmol·L-1, for example 50 μmol·L-1, can be used to screen the cucumber germplasms for P efficiency.

    • A comparative study of postharvest physiology and nutrient components between Guiken 3 and Hass avocado fruits

      2015, 36(3):59-64. DOI: 10.7671/j.issn.1001-411X.2015.03.011

      Abstract (1702) HTML (649) PDF 464.04 K (2405) Comment (0) Favorites

      Abstract:【Objective】Guiken 3 and Hass are the two main avocado, Persea ameriana, cultivars in China. The differences in postharvest physiology and nutrient components between Guiken 3 and Hass avocado during the ripening process were compared. 【Method】 The fruits of Guiken 3 and Hass were harvested and allowed to ripen at 20 ℃. The physiological changes in postharvest and nutrient components during the fruit ripening process were determined.【Result and conclusion】 A climacteric ethylene peak of Guiken 3 was observed on the 5th day,one day earlier than that in Hass, and the peak value was about 5 times higher than that of Hass. During the ripening process, pectinmethylesterase and cellulase activities of Guiken 3 pulp were higher than those in Hass, and propectin pectin and soluble pectin contents were lower than those in Hass. Moreover, cell membrane permeability of Guiken 3 pulp was higher and the pulp firmness was lower than those of Hass. The oil, protein and carotenoid contents increased during the fruit ripening process, while soluble carbohydrate content decreased. The oil content of Hass pulp remained at a higher level during the ripening process than that of Guiken 3 pulp. The oil content reached 21.0% and 11.7% in the ripened Hass and Guiken 3 fruits, respectively. But the soluble protein, soluble carbonhydrate and carotenoid contents of Hass pulp remained at lower levels compared with those of Guiken 3. In the ripened Hass fruits, the contents of soluble protein and carotenoid reached 9.1 mg·g-1 and 6.2 μg·g-1, respectively, while in Guiken 3, they were 17.7 mg·g-1 and 7.8 μg·g-1, respectively. These results indicate that Guiken 3 avocado fruits ripen and soften more quickly than Hass, and Hass has a higher contents of oil, while Guiken 3 has higher contents of soluble protein and carotenoid.

    • The antifungal activity and crop growth stimulation of growth-promoting rhizobacteria from banana rhizosphere soil

      2015, 36(3):65-70. DOI: 10.7671/j.issn.1001-411X.2015.03.012

      Abstract (1894) HTML (622) PDF 485.68 K (2162) Comment (0) Favorites

      Abstract:【Objective】To investigate the inhibitory effects of four banana growth-promoting rhizobacteria (PGPR) on Fusarium oxysporum f. sp. cubense race 4 and several other important crop pathogens.【Method】 The antifungal activity of PGPR was evaluated in petri dish. The promoting effect of PGPR fermented broth on plant growth was determined in a pot experiment.【Result and conclusion】Four strains of PGPR including Bacillus subtilis , B. amyloliquefaciens , Pseudomonas otitidis and Ps. choloeaphtis isolated from rhizosphere soil of a healthy banana orchard showed a strong inhibitory effect on Fusarium oxysporum f. sp. cubense race 4, a causal agent of banana Fusarium wilt. The four bacteria also displayed antifungal activities against other tested crop pathogens including Alternaria solani, Rhizoctonia solani, Colletotrichum gloeosporioides Penz., C. musarum, F.oxysporum(Schl.) f.sp cucumerinum Owen, F. graminearum and Penorophythora litchi Chen. Ps. otitidis grew much faster than the other three bacteria, and the growth radius of Ps. otitidis was 2.75-, 2.61- and 2.70-fold relative to B. subtilis, B. amyloliquefaciens and Ps. choloeaphtis respectively. Ps. otitidis showed the best inhibitory effect on the tested crop pathogens, and the pathogen inhibition rate of Ps. otitidis to Fusarium oxysporum f. sp. cubense race 4, A.solani, R. solani, C. gloeosporioides Penz., C. musae, F.oxysporum (Schl.) f.sp cucumerinum Owen, F. graminearum and Pe. litchi was 50.70%, 62.95%, 70.85%, 68.10%, 58.58%, 59.30%, 51.34% and 63.08% respectively. The fermented broth of Ps. otitidis stimulated the seedling growth of tomatoes and corns, and it increased their shoot height by 16% and 33% respectively. It also increased the chlorophyll content of tomatoes by 40%. These results suggest that Ps. otitidis has strong antifungal activity against crop pathogens and also stimulate the growth of tomatoes and corns.

    • Attractions of volatiles from wax-apple fruit to the oriental fruit fly

      2015, 36(3):71-77. DOI: 10.7671/j.issn.1001-411X.2015.03.013

      Abstract (2069) HTML (317) PDF 550.24 K (2290) Comment (0) Favorites

      Abstract:【Objective】To study the attractions of volatiles from Syzyzgium samarangense (Blume) fruit to Bactrocera dorsalis (Hendel). 【Method】 The ripe fruits of five wax-apple varieties (black pearl, Indian red, big leaf, Thailand red diamond, palm) and five different developmental stages of the black pearl fruit were selected as materials. The behavioral responses of the oriental fruit fly to their volatiles were examined with the Y-tube olfactometer, and ovipositional preference of the insect to five wax-apple varieties were conducted. The volatile components from the ripe fruit of five wax-apple varieties were analyzed with the method of solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) technology. Based on the change of volatile components of different developmental stages of black pearl and combined with the volatile components of five varieties, lure experiments of B. dorsalis to 9 types of synthetic monomer compounds were performed. 【Result and conclusion】 Five wax-apple varieties and different developmental stages of the black pearl fruit had no attraction to males (P>0.05). Different varieties had different degrees of attractions to females: black pearl (40.75%)>Indian red (39.40%)>big leaf (34.76%)>Thailand red diamond (23.02%)>palm (15.54%). Attractions of different developmental stages of the black pearl fruit to mature females increased gradually with the maturity. The results of ovipositional preference [black pearl (517.0), Indian red (433.0), big leaf (357.0), Thailand red diamond (305.7), palm (200.0)] were basically the same as olfactory responses. Main components and relative contents of volatiles were black pearl (12, 80.27%), Indian red (6, 23.56%), big leaf (6, 69.90%), Thailand red diamond (11, 96.97%) and palm (9, 95.1%),which indicated that their volatile components had great differences. Isobutyl acetate, decanal, β-caryophyllene and camphor had significant attractions to females. γ-terpinene, α-farnesene and 1,2-benzenedicarboxylic acid bis(2-methylpropyl) ester had obvious attractions to the mature females. Isobutyl acetate, γ-terpinene and camphor had attractions to males. As for the same compound, the attraction to the mature adults was stronger than that to the immature adults, while the attraction to females was considerably greater than that to males, with the attraction to the mature females being the strongest.

    • Screening of phosphorus-solubilizing strain Burkholderia cenocepacia and optimizing of phosphate-dissolving culture condition

      2015, 36(3):78-82. DOI: 10.7671/j.issn.1001-411X.2015.03.014

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      Abstract:【Objective】To isolate and screen phosphorus-solubilizing strains from the rhizospheric soil in phosphate ore zone and to optimize its phosphorus-solubilizing condition.【Method】 Dilution and plating were applied to screen and purify phosphorus-solubilizing strains. The whole-cell fatty acid was analyzed by gas chromatography and 16S rDNA sequence was identified. The orthogonal design test was used in optimizing phosphorus-solubilizing condition.【Result and conclusion】 Total 22 phosphorus-solubilizing strains were obtained by the traditional methodologies. YN2014102 strain showed a strong ability to dissolve phosphate, which could get 244.75 mg·L-1 available phosphorus from the 10 g·L-1 phosphate rock medium.YN2014102 strain was identified as Burkholderia cenocepacia based on its gas chromatography analysis of whole-cell fatty acid and 16S rDNA sequencing. When the bacterium was cultured in the 10 g·L-1 phosphate rock powder medium at 28 ℃ in a shaker with 180 r·min-1 for 5 days, the dissolve effect of solubilizing phosphorus was the best,which can obtain 277.08 mg·L-1 of available phosphorus in the medium.

    • Differences of GS gene family members expression and analyses of GS activation in different parts of three types of soybean at whole growth stage

      2015, 36(3):83-90. DOI: 10.7671/j.issn.1001-411X.2015.03.015

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      Abstract:【Objective】The purpose of this study was to explore the expression differences of glutamine synthetase (GS) gene family members in 3 types of soybean during growth stages and understand the characteristics of protein formation of soybean with high protein content. 【Method】GS gene expression quantity and glutamine synthetase activaty (GSA) in root, stem, leaf and root nodul from three tested materials, Glycine max, G. max with high protein content and G. soja with high protein content, were investigated at whole growth stage, respectively. 【Result and conclusion】The results were two as follows: the expression of each GS gene member in different organs of three types of soybean was obviously different. GSβ1 in root, stem,leaf and root nodules all expressed high. The expression quantity of GS2 in leaf was significantly higher than that of the other two organs and root nodules. The expression of GSγ1 in nodule increased, while the expression of GSγ1 in roots, stems, leaf was very low. The expression quantity of GSβ1 in root, stem, leaf and root nodules in whole growth period, GS2 in leaf, GSγ1 in root no-dule and the general expression quantity of GS genes at V3-R3 stages were higher in high protein soybean variety than those of normally cultivated soybean variety. This variation was consistent with the variational rule of GSA of three types of soybean. Compared with G. max, effectively regulating the expression of GS gene family members and obtaining high GSA in the whole growth period are characteristics of high protein content soybean.

    • Cloning and prokaryotic expression of hexokinase gene from Dimocarpus longan

      2015, 36(3):91-97. DOI: 10.7671/j.issn.1001-411X.2015.03.016

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      Abstract:【Objective】Hexokinase gene (named DlHXK) was cloned from longan, Dimocarpus longan cv. Shixia, fruit. The bioinformatics and prokaryotic expression of DlHXK were analyzed.【Method】 Total RNA extracted from longan fruit was used as a template. The full length cDNA of the gene was cloned using a combination of RT-PCR and RACE-PCR. Prokaryotic expression vector pET-32a-DlHXK was constructed and transformed into Escherichia coli Rosetta (DE3) to induce expression.【Result and conclusion】 The full length cDNA of DlHXK was cloned and its NCBI GeneBank accession number was KF776906.1,which has 2 101 bp nucleotides including a 1 488 bp ORF. It was predicted to encode 495 amino acids. It had the highest homology with the Citrus unshiu (82%) through the NCBI and evolutionary tree analysis. The results of quantitative RT-PCR showed that DlHXK gene expression increased gradually during the longan fruit maturation. Induced by IPTG and determinated by SDS-PAGE, the inducing expressed recombinant protein from prokaryotic expression vector was consistent with the putative protein of DlHXK. Therefore, the full length of DlHXK has been cloned and its prokaryotic expression vector has been constructed successfully. It was induced to express effectively in E. coli Rosetta (DE3).

    • Identification of a new strain of Tricholoma giganteum by ITS and optimization of culture medium for mycelium

      2015, 36(3):98-103. DOI: 10.7671/j.issn.1001-411X.2015.03.017

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      Abstract:【Objective】A new wild strain of Tricholoma giganteum was identified and the culture medium of mycelium was optimized. 【Method】 The pure mycelium of T. giganteum was obtained from the wild fruitbody by the tissue isolation and identified by molecular biological techniques. The culture condition of the mycelium was researched by measuring mycelial growth rate and growth vigor. The optimum growth medium of mycelium was determined by the uniform-design-method. The method of quadratic polynomial step regression analysis was employed for analyzing the experiment results. 【Result and conclusion】 The wild strain was identified as T. giganteum, named as SCAU3. The accession number of ITS sequence was JX193694 in GeneBank. The results show that the optimum carbon source and nitrogen source for mycelium growth are maltose and yeast extract respectively. The optimum temperature is 30-32 ℃, and the optimum pH in medium was 7-8. The optimum medium for mycelial growth is maltose 26 g·L-1, yeast extract 2 g·L-1, MgSO4 2.7 g·L-1, KH2PO4 1.8 g·L-1, vitamin B1 16 mg·L-1, pH7.7.

    • Establishment and optimization of SRAP-PCR system in Melia azedarach

      2015, 36(3):104-108. DOI: 10.7671/j.issn.1001-411X.2015.03.018

      Abstract (1820) HTML (245) PDF 714.31 K (2107) Comment (0) Favorites

      Abstract:【Objective】In order to study the genetic diversity and evaluate the germplasm resources of Melia azedarach using SRAP markers, the concentration of DNA template, dNTPs,Mg2+, primer and Taq polymerase were tested to determine their optimal levels and establish the optimal SRAP reaction system in M. azedarach.【Method】Five factors, each with 8 concentration levels, were conducted to screen their feasible concentration range using single factor experiment, and then the orthogonal experiment L16(45) was carried out and the optimized system was determined.【Result and conclusion】The concentration range of DNA template was wider in SRAP system in M. azedarach. When the concentration of dNTPs ranged from 0.1 to 0.2 mmol·L-1, the bands were steady; when the concentration of Mg2+ was around 2.0 mmol·L-1, more bands were amplified and clear. The band type was consistent and clear when the primer concentration ranged from 0.48 to 0.64 μmol·L-1. When the Taq polymerase ranged from 0.50 to 2.00 U, more bands were amplified and clear. The optimum SRAP-PCR system was established on the basis of orthogonal experiment, which was DNA template 30 ng, dNTPs 0.125 mmol·L-1, Mg2+ 2.25 mmol·L-1, primers 0.48 μmol·L-1, and Taq DNA polymerase 0.75 U in the 25 μL reaction system.

    • Anatomical characteristics and fiber morphology of cassava stems

      2015, 36(3):109-113. DOI: 10.7671/j.issn.1001-411X.2015.03.019

      Abstract (1525) HTML (443) PDF 2.76 M (2555) Comment (0) Favorites

      Abstract:【Objective】The aim of this research was to study anatomical features and the adaptations of fiber cells of the cassava stem for pulp-making of paper and fiberboard. 【Method】Anatomical structure and fiber morphology of the cassava stems were studied using optical microscopy and scanning electron microscope. 【Result and conclusion】The pith dimension of a cassava stem near the root was smaller than its upper part. Perennial cassava stems with branches were well lignified, and the volume ratio of pith was far below that of annual ones. Cassava stems were composed of diffuse porous wood. Their cells consisted of duct, wood fiber cells and xylem ray, and most of them were radial multiple pores. There were alternate pitting and scalariform pitting in the duct. The wood had uniseriate wood ray, a few fiber cells with bordered pit, and abundant starch granule in wood ray and fiber cells. The perennial stem fiber cell wall was 1.5 times thicker than that of the branches, and was over 2 times thicker than that of annual ones. Fiber cell length was 638-661 μm, and length-width ratio was 36.22-37.43. The ratio of wall-thickness to lumen-diameter of fiber cells was 0.14-0.32, mostly in 500-900 and 10-25 μm,thus belonging to the thin cell wall and short fiber type and meeting the requirements of paper and fiberboard industry for raw material.

    • Cooling characteristics of different precooling methods for litchi

      2015, 36(3):114-119. DOI: 10.7671/j.issn.1001-411X.2015.03.020

      Abstract (1619) HTML (579) PDF 1.14 M (2937) Comment (0) Favorites

      Abstract:【Objective】To study the cooling characteristics of different precooling methods for litchi. 【Method】 A pressure-difference precooling test chamber was established. Four precooling methods, including ice water(L1), cold storage(L2), pressure-difference(L3) and forced-air pressure-difference with high humidity (L4), were adopted for “Huaizhi” litchi. 【Result and conclusion】 The results showed that L1, L2, L3 and L4 spent 35, 55, 64 and 345 min respectively to precool the litchi down to the target temperature (5 ℃). The cooling procedure of litchi fruit at different positions for L1 performed no significant difference. L2 took 195, 258 and 228 min to precool litchi at left and right positions and top layer respectively. However, the fruit temperature at middle and bottom layer and middle position were still up to 5.37, 6.16 and 7.37 ℃ respectively after 345 min precooling; and the cooling procedure of litchi fruit showed significant differences between the left, right position and its middle position. L3 took 39, 52, 42 min to precool litchi at the left and right positions and top layer respectively. However, the fruit temperature at middle and bottom layers and middle position were still up to 6.03, 5.67 and 9.03 ℃ respectively after 55 min precooling. The cooling procedure of litchi fruit showed significant difference among the top layer, left position and its middle and bottom layers. L4 spent 39 and 41 min to precool litchi at the left position and top layer respectively. However, the fruit temperature at the middle and bottom layers, middle and right positions were still respectively up to 5.86,8.83, 7.87 and 6.63 ℃ after 64 min precooling. The cooling procedure of litchi fruit showed a significant difference between the left position and its middle position. L1 has high cooling efficiency and good fruit temperature uniformity,which is suitable for cooling litchi.

    • Design and optimization of rotary drum combing type of litchi picking machine

      2015, 36(3):120-124. DOI: 10.7671/j.issn.1001-411X.2015.03.021

      Abstract (1581) HTML (495) PDF 899.88 K (2403) Comment (0) Favorites

      Abstract:【Objective】To design a rotary drum combing type litchi picker and optimize structures of picking parts. 【Method】 The four-factor and three-level orthogonal experiment was conducted, using the amount of tooth profile plate, the bend angle of tooth profile plate, the amount of blade and the drum rotation speed as influencing factors, and productivity, picking rate and crushing rate as picking indexes. 【Result and conclusion】 The optimal parameter combination was 4 for the amount of tooth profile plate, 120° for the bend angle of tooth profile plate, 13 for the amount of blade and 44 r·min-1 for the drum rotation speed The productivity reached 2.604 kg·min-1 based on the optimal parameter combination. The results provide reference for design and development of litchi picking machine.