Comparison of photobioreactors and optimal light regime for rapid vegetative propagation of transgenic Undaria pinnatifida gametophytes

BACKGROUND: Previously, tachyplesin gene (tac) has been successfully transferred into Undaria pinnatifida gametophytes using the method of microprojectile bombardment transformation. The objectives of this study were to compare and evaluate the performance of bubble-column and airlift bioreactors to determine a preferred configuration of bioreactor for vegetative propagation of transgenic U. pinnatifida gametophytes, and to then investigate the influence of light on vegetative propagation of these gametophytes, including incident light intensity, photoperiod and light quality to resolve the problems of rapid vegetative propagation within the selected bioreactor. RESULTS: Experimental results showed that final dry cell density in the airlift bioreactor was 12.7% higher than that in the bubble-column bioreactor under the optimal aeration rate of 1.2 L air min(-1) L-1 culture. And a maximum final dry cell density of 2830 mg L-1 was obtained within the airlift bioreactor using blue light at 40 mu mol m(-2) s(-1) with a light/dark cycle of 14/10 (h). Polymerase chain reaction (PCR) analysis indicated that genes (bar and tac) were not lost during rapid vegetative propagation within the airlift bioreactor. CONCLUSION: The airlift bioreactor was shown to be much more suitable for rapid vegetative propagation of transgenic U. pinnatifida gametophytes than the bubble-column bioreactor in the laboratory. The use of blue light allows improvement of vegetative propagation of transgenic U. pinnatifida gametophytes. (C) 2009 Society of Chemical Industry

Microprojectile bombardment of Laminaria japonica gametophytes and rapid propagation of transgenic lines within a bubble-column bioreactor

A human acidic fibroblast growth factor gene, hafgf, was successfully transferred into Laminaria japonica (kelp) gametophytes via microprojectile bombardment using the biolistic PDS-1000/He gene gun. Following phosphinothricin screening, PCR detection and Southern blot analysis, transgenic L. japonica gametophytes were cultivated in an illuminated bubble-column bioreactor to optimize growth conditions. A maximal final dry cell density of 1,695 mg l(-1) was obtained in a batch culture having an initial dry cell density of 129.75 mg l(-1). This was achieved using an aeration rate of 1.08 l air min(-1) l(-1) culture in a medium containing 1.5 mM inorganic nitrate and 0.15 mM phosphate. In addition, the relationship between different nitrogen sources and growth of transgenic gametophytes indicated that both urea and sodium nitrate were effective nitrogen sources for cell growth, while ammonium ions inhibited growth of these gametophytes.

Rapid detection of virulent protease secreted by Vibrio anguillarum by dot enzyme-linked immunosorbent assay

Dot enzyme-linked immunosorbent assay (dot-ELISA), indirect ELISA and Western blot were performed to detect the virulent protease secreted by Vibrio anguillarum which was isolated from the diseased left-eyed flounder, Paralichthys olivaceous. Sensitivity results showed that dot-ELISA is a more sensitive, rapid and simple technique for the protease detection. The minimal detectable amount of protease is about 7 pg in the dot-ELISA test, while 7.8 ng in the indirect ELISA and 6.25 ng in the Western blot respectively. Protease could be detected 2 h after incubation of V. anguillarum in the 2216E liquid medium but enzyme activity was very low at that period. From 6 to 12 h, the amount and enzyme activity of protease increased markedly and reached maximum at stationary phase. Analysis of serum samples periodically collected from the infected flounders showed that after 2 h of infection by V. anguillarum, the pathogenic bacteria could be detected in the blood of the infected flounders but no protease was found. It was 5 similar to 6 h after infection that the protease was detected in blood and then the amount increased as infection advanced. Quantitative detection of protease either incubation in the medium or from the blood of infected flounders could be accomplished in virtue of positive controls of quantificational protease standards ("marker") so that the alterations of protease secretion both in vitro and in vivo could be understood generally. In addition, the indirect ELISA and dot-ELISA were also performed to detect V. anguillarum cells. Results indicated that the sensitivity of indirect ELISA to bacteria cells is higher than that of the dot-ELISA, and that the minimal detectable amount is approximately 10(4) cell/mL in the indirect ELISA, while 10(5) cell/mL in the dot-ELISA.

Rapid optimization of process conditions for cultivation of transgenic Laminaria japonica gametophyte cells in a stirred-tank bioreactor

Batch cultivation for transgenic kelp gametophyte cells was investigated in an online controlled 5 L stirred-tank photo-bioreactor to rapidly optimize the process conditions by monitoring the rate of increase of pH. The transgenic kelp gametophytes with heterologous gene encoding hepatitis B surface antigen (HBsAg) could rapidly grow in the bioreactor. Optimal temperature and agitation rate for bioreactor cultivation of gametophytes were 15 degrees C and 200 rpm. Optimal incident light intensities depended on the initial cell densities. (c) 2006 Elsevier B.V. All fights reserved.

Rapid changes in stocks of ciliate microzooplankton associated with a hurricane in the Bohai Sea (China)

The ciliate community in the Bohai Sea (China) was studied from 23 September to 7 October 1998. A hurricane struck the study area between the 2 grid station investigations; which were 6 d apart. The ciliate biomass decreased drastically after the hurricane. The surface ciliate biomass decreased from 0.2-12.3 to 0.02-2.8 mug C l(-1) and the water column ciliate biomass from 2-136 to 0.01-47 mg C m(-2). The ciliate biomass:chlorophyll ratios in the surface water were calculated to be 0.04 to 4.7 (1.41 on average) during the first grid investigation and 0.01 to 1.18 (0.26 on average) during the second grid investigation. Distinct patterns of temporal changes in ciliate abundances were found at different stations both before and after the hurricane.

Sensitive and Rapid Detection of Genetic Modified Soybean (Roundup Ready) by Loop-Mediated Isothermal Amplification

Using the LAMP method, a highly specific and sensitive detection system for genetically modified soybean (Roundup Ready) was designed. In this detection system, a set of four primers was designed by targeting the exogenous 35S epsps gene. Target DNA was amplified and visualized on agarose gel within 45 min under isothermal conditions at 65 degrees C. Without gel electrophoresis, the LAMP amplicon was visualized directly in the reaction tube by the addition of SYBR Green I for naked-eye inspection. The detection sensitivity of LAMP was 10-fold higher than the nested PCR established in our laboratory. Moreover, the LAMP method was much quicker, taking only 70 min, as compared with 300 min for nested PCR to complete the analysis of the GM soybean. Compared with traditional PCR approaches, the LAMP procedure is faster and more sensitive, and there is no need for a special PCR machine or electrophoresis equipment. Hence, this method can be a very useful tool for GMO detection and is particularly convenient for fast screening.

Experimental warming causes large and rapid species loss, dampened by simulated grazing, on the Tibetan Plateau

We investigated the independent and combined effects of experimental warming and grazing on plant species diversity on the north-eastern Tibetan Plateau, a region highly vulnerable to ongoing climate and land use changes. Experimental warming caused a 26-36% decrease in species richness, a response that was generally dampened by experimental grazing. Higher species losses occurred at the drier sites where N was less available. Moreover, we observed an indirect effect of climate change on species richness as mediated by plant-plant interactions. Heat stress and warming-induced litter accumulation are potential explanations for the species' responses to experimental warming. This is the first reported experimental evidence that climate warming could cause dramatic declines in plant species diversity in high elevation ecosystems over short time frames and supports model predictions of species losses with anthropogenic climate change.

Rapid authentication of ginseng species using microchip electrophoresis with laser-induced fluorescence detection

Ginseng is one of the most expensive Chinese herbal medicines and the effectiveness of ginseng depends strongly on its botanical sources and the use of different parts of the plants. In this study, a microchip electrophoresis method coupled with the polymerase chain reaction (PCR)-short tandem repeats (STR) technique was developed for rapid authentication of ginseng species. A low viscosity hydroxypropyl methylcellulose (HPMC) solution was used as the sieving matrix for separation of the amplified STR fragments. The allele sizing of the amplified PCR products could be detected within 240 s or less. Good reproducibility and accuracy of the fragment size were obtained with the relative standard deviation for the allele sizes less than 1.0% (n = 11). At two microsatellite loci (CT 12, CA 33), American ginseng had a different allele pattern on the electropherograms compared with that of the Oriental ginseng. Moreover, cultivated and wild American ginseng can be distinguished on the basis of allele sizing. This work establishes the feasibility of fast genetic authentication of ginseng species by use of microchip electrophoresis.