Selection of Anti-Sulfadimidine Specific ScFvs from a Hybridoma Cell by Eukaryotic Ribosome Display

BACKGROUND:Ribosome display technology has provided an alternative platform technology for the development of novel low-cost antibody based on evaluating antibiotics derived residues in food matrixes. METHODOLOGY/PRINCIPAL FINDINGS:In our current studies, the single chain variable fragments (scFvs) were selected from hybridoma cell lines against sulfadimidine (SM(2)) by using a ribosome library technology. A DNA library of scFv antibody fragments was constructed for ribosome display, and then mRNA-ribosome-antibody (MRA) complexes were produced by a rabbit reticulocyte lysate system. The synthetic sulfadimidine-ovalbumin (SM(2)-OVA) was used as an antigen to pan MRA complexes and putative scFv-encoding genes were recovered by RT-PCR in situ following each panning. After four rounds of ribosome display, the expression vector pCANTAB5E containing the selected specific scFv DNA was constructed and transformed into Escherichia coli HB2151. Three positive clones (SAS14, SAS68 and SAS71) were screened from 100 clones and had higher antibody activity and specificity to SM(2) by indirect ELISA. The three specific soluble scFvs were identified to be the same molecular weight (approximately 30 kDa) by Western-blotting analysis using anti-E tag antibodies, but they had different amino acids sequence by sequence analysis. CONCLUSIONS/SIGNIFICANCE:The selection of anti-SM(2) specific scFv by in vitro ribosome display technology will have an important significance for the development of novel immunodetection strategies for residual veterinary drugs

Seasonal patterns and environmental drivers of nirS- and nirK-encoding denitrifiers in sediments of Daya Bay, China

Summary: The seasonal patterns of the denitrifiers (denitrifying bacteria) in the sediment of Daya Bay, southern China, were examined using quantitative PCR and high-throughput MiSeq sequencing methods in spring, summer and winter. The abundance and diversity of nirS-encoding denitrifiers were much higher than that of nirK-encoding denitrifiers, indicating that the former probably dominated the denitrification processes in sediments of Daya Bay. The average abundance and diversity of nirS-encoding denitrifiers were much higher in spring than that in summer and winter, on the other hand, the abundance of nirK-encoding denitrifiers showed the opposite pattern. The species composition of nirS-encoding denitrifiers community in spring differed significantly from that in summer and winter, whereas, no significant difference existed between summer and winter. The dominant environmental drivers for the diversity of community species were NO2−, NO3− and DO concentrations. The abundances of dominant genera of nirS- encoding denitrifiers, Accumulibacter sp. and Cuprizvidus sp., were significantly higher in summer and winter than that in spring, and were negatively correlated with NO2−, NO3−, and DO concentrations (p < 0.05). In contrast, the abundances of Azoarcus sp. and Halomonas sp., were highest in spring, and were positively correlated with NO3− and NO2− content (p < 0.05). For nirK-encoding denitrifiers, a significant difference in community composition was observed between spring and winter. No obvious correlation was found between community composition of nirK-encoding denitrifiers and environmental parameters. Keywords: Abundance, Community structure, nirS-encoding denitrifiers, nirK-encoding denitrifiers, Sediment, Daya Ba

A first description of ciliate assemblages in a subtropical, eutrophic bay, South China Sea: species assemblage and environmental correlates

The ciliate community together with physical-chemical variables was investigated in a subtropical, eutrophic bay of the South China Sea from January 7–10 (dry season) and April 27–30 (wet season), 2012. Both temperature and salinity exhibited typical seasonality. A total of 27 species of ciliates belonging to 19 genera were identified, and the dominant species were Strombidium globosaneum in January and Codonella rapa in April. The composition and abundance exhibited spatial and temporal fluctuations, with total mean abundance of ciliates in April (1219 ± 919 ind l-1), was much higher than that in January (283 ± 137 ind l-1). Spatially, high species numbers were found mainly near the mouth of the estuary, and the abundance decreased from inside to the mouth of the bay. Statistical analysis showed that ciliate assemblages were closely related to the environmental variables. The distribution patterns of salinity and chlorophyll a concentration were similar, suggesting that, prey abundance may correlate significantly with ciliate abundance, and salinity may not be the main factor explaining the spatial variation in the ciliate community in the study area

Suitability of two seaweeds, Gracilaria lemaneiformis and Sargassum pallidum, as feed for the abalone Haliotis discus hannai Ino

The suitability of two algae species, Gracilaria lemaneiformis and Sargassum pallidum, for use as food sources for the abalone Haliotis discus hannai Ino was evaluated. Abalones were fed one of five experimental diets: 1) kelp Laminari japonica: 2) G. lemaneiformis: 3) S. pallidum; 4) a mixed diet of L. japonica and G. lemaneiformis (1:1); and 5) a mixed diet of L. japonica and S. pallidum (1:1) for a period of 4 months. The survival, growth (shell length and body weight), condition index (body weight/shell length), and feed utilization were measured. Survival was excellent (100%) in all groups. Growth rate (body weight) was highest in the abalone fed kelp exclusively, followed by the mixed diet of kelp and G. lemaneiformis. The abalone fed S. pallidum had the lowest increase in body weight and the lowest feed intake. The mixed diet of kelp and G. lemaneiformis yielded the biggest increase in shell length. There were no significant differences in the condition index among all the treatment groups. The mean daily feed intake of L japonica was highest, followed by the mixed diets of kelp and G. lemaneiformis, and was lowest for S. pallidum. Abalone exhibited a preference for L japonica. The feed conversion efficiency was highest for G. lemaneiformis. Results suggest that G. lemaneiformis can be used as a partial substitute for kelp in the diet of cultured abalone. (C) 2010 Elsevier B.V. All rights reserved.The suitability of two algae species, Gracilaria lemaneiformis and Sargassum pallidum, for use as food sources for the abalone Haliotis discus hannai Ino was evaluated. Abalones were fed one of five experimental diets: 1) kelp Laminari japonica: 2) G. lemaneiformis: 3) S. pallidum; 4) a mixed diet of L. japonica and G. lemaneiformis (1:1); and 5) a mixed diet of L. japonica and S. pallidum (1:1) for a period of 4 months. The survival, growth (shell length and body weight), condition index (body weight/shell length), and feed utilization were measured. Survival was excellent (100%) in all groups. Growth rate (body weight) was highest in the abalone fed kelp exclusively, followed by the mixed diet of kelp and G. lemaneiformis. The abalone fed S. pallidum had the lowest increase in body weight and the lowest feed intake. The mixed diet of kelp and G. lemaneiformis yielded the biggest increase in shell length. There were no significant differences in the condition index among all the treatment groups. The mean daily feed intake of L japonica was highest, followed by the mixed diets of kelp and G. lemaneiformis, and was lowest for S. pallidum. Abalone exhibited a preference for L japonica. The feed conversion efficiency was highest for G. lemaneiformis. Results suggest that G. lemaneiformis can be used as a partial substitute for kelp in the diet of cultured abalone. (C) 2010 Elsevier B.V. All rights reserved

Safety Risk and Strategy Analysis of On-Board Hydrogen System of Hydrogen Fuel Cell Vehicles in China

Hydrogen fuel cell vehicles (HFCVs) represent an important breakthrough in the hydrogen energy industry. The safe utilization of hydrogen is critical for the sustainable and healthy development of hydrogen fuel cell vehicles. In this study, risk factors and preventive measures are proposed for on-board hydrogen systems during the process of transportation, storage, and use of fuel cell vehicles. The relevant hydrogen safety standards in China are also analyzed, and suggestions involving four safety strategies and three safety standards are proposed

Research on the Algorithm Model for Measuring Ocean Waves Based on Satellite GPS Signals in China

In recent years, the GPS wave buoy has been developed for in situ wave monitoring based on satellite GPS signals. Many research works have been completed on the GPS-based wave measurement technology and great progress has been achieved. The basic principle of the GPS wave buoy is to calculate the movement velocity of the buoy using the Doppler frequency shift of satellite GPS signals, and then to calculate the wave parameters from the movement velocity according to ocean wave theory. The shortage of the GPS wave buoy is the occasional occurrence of some unusual values in the movement velocity. This is mainly due to the fact that the GPS antenna is occasionally covered by sea water and cannot normally receive high-quality satellite GPS signals. The traditional solution is to remove these unusual movement velocity values from the records, which requires furthering extend the acquisition time of satellite GPS signals to ensure there is a large enough quantity of effective movement velocity values. Based on the traditional GPS wave measurement technology, this paper presents the algorithmic flow and proposes two improvement measures. On the one hand, the neural network algorithm is used to correct the unusual movement velocity data so that extending the acquisition time of satellite GPS signals is not necessary and battery power is saved. On the other hand, the Gaussian low-pass filter is used to correct the raw directional wave spectrum, which can further eliminate the influence of noise spectrum energy and improve the measurement accuracy. The on-site sea test of the SBF7-1A GPS wave buoy, developed by the National Ocean Technology Center in China, and the gravity-acceleration-type DWR-MKIII Waverider buoy are highlighted in this article. The wave data acquired by the two buoys are analyzed and processed. It can be seen from the processed results that the ocean wave parameters from the two kinds of wave buoys, such as wave height, wave period, wave direction, wave frequency spectrum, and directional wave spectrum, are in good consistency, indicating that the SBF7-1A GPS wave buoy is comparable to the traditional gravity-acceleration-type wave buoy in terms of its accuracy. Therefore, the feasibility and validity of the two improvement measures proposed in this paper are confirmed

Genome-Wide Analysis of Auxin Response Factors in Lettuce (Lactuca sativa L.) Reveals the Positive Roles of LsARF8a in Thermally Induced Bolting

Warm temperatures induce plant bolting accompanied by flower initiation, where endogenous auxin is dynamically associated with accelerated growth. Auxin signaling is primarily regulated by a family of plant-specific transcription factors, AUXIN RESPONSE FACTORS (ARFs), which either activate or repress the expression of downstream genes in response to developmental and environmental cues. However, the relationship between ARFs and bolting has not been completely understood in lettuce yet. Here, we identified 24 LsARFs (Lactuca sativa ARFs) in the lettuce genome. The phylogenetic tree indicated that LsARFs could be classified into three clusters, which was well supported by the analysis of exon&ndash;intron structure, consensus motifs, and domain compositions. RNA-Seq analysis revealed that more than half of the LsARFs were ubiquitously expressed in all tissues examined, whereas a small number of LsARFs responded to UV or cadmium stresses. qRT-PCR analysis indicated that the expression of most LsARFs could be activated by more than one phytohormone, underling their key roles as integrative hubs of different phytohormone signaling pathways. Importantly, the majority of LsARFs displayed altered expression profiles under warm temperatures, implying that their functions were tightly associated with thermally accelerated bolting in lettuce. Importantly, we demonstrated that silencing of LsARF8a, expression of which was significantly increased by elevated temperatures, resulted in delayed bolting under warm temperatures, suggesting that LsARF8a might conduce to the thermally induced bolting. Together, our results provide molecular insights into the LsARF gene family in lettuce, which will facilitate the genetic improvement of the lettuce in an era of global warming

Contrasting roles of Bi-doping and Bi 2 Te 3 alloying on the thermoelectric performance of SnTe

Previous studies have revealed that both Bi doping and Bi2Te3 alloying are successful strategies to optimize the thermoelectric performance of SnTe; however, detailed and thorough investigations on exactly how they differ in modulating the band structure and microstructure were seldom given. Through a systematic comparison between Bi-doped and Bi2Te3-alloyed SnTe, we find in this work that despite the fact that they both contribute to the valence band convergence of SnTe, Bi2Te3 alloying induces little effect on the hole concentration unlike the typical n-type feature of Bi-doping; moreover, Bi2Te3 alloying tends to produce dense dislocation arrays at micron-scale grain boundaries which differs significantly from the substitutional point defect character upon Bi-doping. It was then found that Bi2Te3 alloying exhibits a relatively higher quality factor (B ∼ μw/κlat) at higher temperatures than Bi-doping. Subsequent Ge-doping in Bi2Te3-alloyed samples results in further valence band convergence and hole concentration optimization and eventually results in a maximum figure of merit ZT of 1.4 at 873 K in the composition of (Sn0.88Ge0.12Te)0.97-(BiTe1.5)0.03