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African swine fever virus (ASFV) causes hemorrhagic infectious disease in pigs with a fatality rate of nearly 100%. In this study, we developed a visual strand exchange amplification detection assay for ASFV. In the presence of ASFV, DNA amplification products containing multimeric G-quadruplex sequences were amplified by strand exchange amplification. These G-quadruplexes, assembled with hemin to form DNAzyme, displayed enhanced significant "turned-on" colorimetric signals to indicate detection results. The results showed that dimeric DNAzyme had the best visualization effect. Under the optimal reaction parameters, there was a linear relationship between the absorbance of the reaction solution at 417 nm and the logarithm of ASFV concentration ranged from 1 × 10

Cronobacter sakazakii is an important opportunistic food-borne pathogen, and it can cause severe diseases with main symptoms including neonatal meningitis, necrotizing enterocolitis, and sepsis. For the achievement of practical and convenient detection of viable C. sakazakii, a simple and robust strategy based on the cascade signal amplification of RT-PCR triggered G-quadruplex DNAzyme catalyzed reaction was firstly used to develop an effective and sensitive DNAzyme electrochemical assay. Without viable C. sakazakii in the samples there are no RT-PCR and DNAzyme products, which can cause a weak electrochemical response. Once viable C. sakazakii exists in the samples, an obvious enhancement of the electrochemical response can be achieved after the target signal is amplified by RT-PCR and the resulting DNAzyme, which catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 with the assistance of the cofactor hemin. Our novel assay can be performed in a range of 2.4 × 107 CFU mL-1 to 3.84 × 104 CFU mL-1 (R2 = 0.9863), with a detection limit of 5.01 × 102 CFU mL-1. Through the assay of 15 real samples, electrochemical detection assay provided the same results as conventional detection methods. Therefore, detection of viable C. sakazakii based on G-quadruplex DNAzyme electrochemical assay with RT-PCR demonstrates the significant advantages of high sensitivity, low cost and simple manipulation over existing approaches and offers an opportunity for potential application in pathogen detection.

Machine learning algorithms as a powerful tool can efficiently utilize and process large quantities of data generated by high-throughput experiments in various fields. In this work, we used a general ionic salt-assisted synthesis method to prepare oxidase-like Fe-N-C SANs. The possible reason for the excellent enzyme-mimicking activity and affinity of Fe-N-C SANs was further verified by density functional theory calculations. Due to the remarkable oxidase-mimicking activity, the prepared Fe-N-C SANs were used to detect ascorbic acid (AA) with a detection limit of 0.5 μM. Based on the machine learning algorithms, we successfully distinguished six antioxidants (ascorbic acid, glutathione, L-cysteine, dithiothreitol, uric acid, and dopamine) with the same concentration by either one kind of Fe-N-C SANs or three kinds of different Fe-N-C SANs. The usefulness of the Fe-N-C SANs sensor arrays was further validated by the hierarchal cluster analysis, where they also can be correctly identified. More importantly, a SANs-based digital-image colorimetric sensor array has also been successfully constructed and thereby achieved visual and informative colorimetric analysis for practical samples out of the lab. This work not only provides a design synthesis method to prepare SANs but also combines machine learning algorithms with SANs sensors to identify analytes with similar properties, which can further expand to the detection of proteins and cells related to diseases in the future.

For early detection and diagnosis of gastric cancer, a novel, highly sensitive detection of microRNA-378 was developed through rolling circle amplification and DNA-templated silver nanoclusters as a lable-free fluorescent probe. DNA-templated fluorescent silver nanoclusters (DNA/AgNCs) to make target signal cascade amplification were prepared and identified through their fluorescent spectrum. MiRNA-378 trigged rolling circle amplification to obtain the complementary sequence (cDNA) to combine with two DNA/AgNCs in the middle of a sandwich structure to induce the new fluorescent signal at a new wavelength. In the presence of microRNA-378, a large amount of RCA product cDNAs were hybridized with DNA/AgNCs as the fluorescence nanocluster beacon, resulting in fluorescence enhanced “turn-on” phenomenon. This study indicated that amplified fluorescence detection of microRNA-378 is a stable, low-cost, highly specific, and ultra-low as 1.07 fM detectability. The proposed approach of signal synergetic amplification facilitating the fluorescence detection microRNA shows great potential for potentially clinically diagnosis.

MicroRNA-378 (miRNA-378) is widely regarded as a novel noninvasive serum biomarker for early detection of gastric cancer. In the current study, a T4 DNA ligase-mediated circular template specific to target and a target-triggering rolling circle amplification (RCA) strategy was proposed for gastric cancer biomarker miRNA-378 visual detection. After multiple signal amplification through RCA and DNAzyme, a simple method for colorimetric detection of miRNA-378 was first developed with an ultralow detection limit of 80 fM per reaction by the naked eye, and synergetic signal cascade amplification enables the assay to have extraordinarily high sensitivity and the potential for clinical diagnosis.

Chloramphenicol (CAP) is a kind of broad-spectrum antibiotic, which has been forbidden in food by most countries because of its side effects. In this study, a simple and low-cost biosensor for CAP detection in food was developed. The biosensor consisted of an aptamer specific to CAP and a pair of split probes that could self-assemble as DNAzyme. The detection result could be identified by the naked eye and the visual limit was 10 nM CAP. The absorbance of final reaction products at 417 nm had a linear relationship with the logarithm of the CAP concentration in a range from 10 to 200 nM, and the limit of detection was 87.3 pM. The visual analysis by imageJ also showed a linear detection range between 25 and 200 nM. The entire detection procedure could be completed in about 1.5 h at a cost of about 0.16 dollars per reaction. We believe that the biosensor shows great potential in the rapid and sensitive detection of CAP in food.

Conifers dominate the world's forest ecosystems and are the most widely planted tree species. Their giant and complex genomes present great challenges for assembling a complete reference genome for evolutionary and genomic studies. We present a 25.4-Gb chromosome-level assembly of Chinese pine (Pinus tabuliformis) and revealed that its genome size is mostly attributable to huge intergenic regions and long introns with high transposable element (TE) content. Large genes with long introns exhibited higher expressions levels. Despite a lack of recent whole-genome duplication, 91.2% of genes were duplicated through dispersed duplication, and expanded gene families are mainly related to stress responses, which may underpin conifers' adaptation, particularly in cold and/or arid conditions. The reproductive regulation network is distinct compared with angiosperms. Slow removal of TEs with high-level methylation may have contributed to genomic expansion. This study provides insights into conifer evolution and resources for advancing research on conifer adaptation and development.

Conifers dominate large parts of the world’s forest ecosystems and are the most widely planted tree species. Their huge and highly complex genomes pose great challenges for assembling a complete reference genome for various evolutionary and genomic studies. Here, we present a chromosome-scale genome assembly of Pinus tabuliformis comprising 25.4 gigabases. A total of 80,495 genes were annotated based on massive RNA-seq data from 760 biosamples. These data provides novel insights into conifer unique genomic features and adaptive evolution. We presented the first chromosome-scale methylation maps of huge conifer genome, and revealed a high concordance between TE content and methylation level, yet there was no clear correlation between TE insertion time and the methylation level. These results provide us an unprecedented opportunity to conduct evolutionary and genomics studies on its unique adaptation, developmental and secondary growth, reproductive biology, and genomics-assisted breeding.

Listeria monocytogenes is a kind of foodborne pathogen, which can cause meningitis, septicemia, gastroenteritis, and abortion with a fatality rate of up to 30%. Rapid, sensitive, and convenient detection of L. monocytogenes in food is an important strategy for controlling contamination and infection. In this study, an enhanced visual detection assay for L. monocytogenes based on an isothermal amplified peroxidase-mimicking catalytic beacon was developed. When L. monocytogenes existed, G-quadruplex sequences were amplified together with targeted gene sequence by polymerase spiral reaction (PSR). G-quadruplex adequately formed DNAzyme with hemin to have an enhanced peroxidase-like bioactivity with help of Nb. BbvCI nicking endonuclease, which could display significant colorimetric signals for indicating positive results qualitatively. The sensitivity test results determined that our assay enabled the quantitative detection of L. monocytogenes ranging from 10 to 105 CFU mL−1, as well as had a detection limit of 3.1 CFU mL−1, which was lower than previous visual detection assays for L. monocytogenes. Besides, it was notable that this assay could detect L. monocytogenes with the concentration of 2.0 lg CFU/g in artificially contaminated pork samples within about 4 h, with the advantages of high sensitivity, simple operation, and good visual signal output. We believed the improved visual detection assay based on isothermal amplified peroxidase-mimicking catalytic beacon showed great potential for food safety analysis.

Listeria monocytogenes is an important foodborne pathogen, which imposes great burdens on public health. The current methods for detecting L. monocytogene are limited in several ways such as time consuming and lab equipment dependent. In this study, we developed a new electrochemical assay to improve the efficacy. This assay allows us to generate numerous G-quadruplex sequences while loop-mediated isothermal amplification happens. Then, these G-quadruplex sequences form DNAzyme to produce a color change and an electrochemical signal by oxidizing tetramethylbenzidine. This assay could be finished in 2 h, which significantly reduced the detection time. Also, we confirmed the limit of detection of this assay at 6.8 CFU/mL according to 3σ criterion. Our assay shows good sensitivity to detect bacteria range from 52.5 to 5.25 × 104 CFU/mL. This assay’s reliability was also confirmed by detecting artificially contaminated pork samples. Thus, we propose this electrochemical assay for rapid and sensitive detection of L. monocytogenes in food.

COVID-19, a new respiratory infectious disease, was first reported at the end of 2019, in Wuhan, China. Now, COVID-19 is still causing major loss of human life and economic productivity in almost all countries around the world. Early detection, early isolation, and early diagnosis of COVID-19 patients and asymptomatic carriers are essential to blocking the spread of the pandemic. This paper briefly reviewed COVID-19 diagnostic assays for clinical application, including nucleic acid tests, immunological methods, and Computed Tomography (CT) imaging. Nucleic acid tests (NAT) target the virus genome and indicates the existence of the SARS-CoV-2 virus. Currently, real-time quantitative PCR (qPCR) is the most widely used NAT and, basically, is the most used diagnostic assay for COVID-19. Besides qPCR, many novel rapid and sensitive NAT assays were also developed. Serological testing (detection of serum antibodies specific to SARS-CoV-2), which belongs to the immunological methods, is also used in the diagnosis of COVID-19. The positive results of serological testing indicate the presence of antibodies specific to SARS-CoV-2 resulting from being infected with the virus. Viral antigen detection assays are also important immunological methods used mainly for rapid virus detection. However, only a few of these assays had been reported. CT imaging is still an important auxiliary diagnosis tool for COVID-19 patients, especially for symptomatic patients in the early stage, whose viral load is low and different to be identified by NAT. These diagnostic techniques are all good in some way and applying a combination of them will greatly improve the accuracy of COVID-19 diagnostics.

A new troodontid dinosaur, Papiliovenator neimengguensis gen. et sp. nov., from the Upper Cretaceous (Campanian) Wulansuhai Formation at Bayan Manduhu, Inner Mongolia, China, is described here. The holotype (BNMNH-PV030) consists of a nearly complete cranium and fragmentary postcranial bones in semi-articulation and this specimen is inferred as a subadult based on the osteohistological information and the fusion of bones. Papiliovenator neimengguensis is distinguishable from other troodontids based on a suite of features such as the lateral groove of the dentary not posteriorly expanded, a deep surangular fossa anteroventral to the glenoid fossa and hosting the surangular foramen, the ventral ridge of the surangular fossa mainly on the surangular, and a unique anterolaterally broadened and butterfly-shaped neural arch of the anteriormost dorsal vertebrae in dorsal view. Our phylogenetic analysis recovered Papiliovenator neimengguensis at the earliest-diverging branch of a clade including all other Late Cretaceous troodontids except Almas. The discovery of Papiliovenator neimengguensis allows for an improved understanding of troodontid anatomy, as well as the regional variation of troodontids from the Upper Cretaceous of the Gobi Basin.

Listeria monocytogenes is an important foodborne pathogen, and it can cause severe diseases. Rapid detection of L. monocytogenes is crucial to control this pathogen. A simple and robust strategy based on the cascade of PCR and G-quadruplex DNAzyme catalyzed reaction was used to detect L. monocytogenes. In the presence of hemin and the aptamer formed during PCR, the catalytic horseradish peroxidase-mimicking G-quadruplex DNAzymes allow the colorimetric responses of target DNA from L. monocytogenes. This assay can detect genomic DNA of L. monocytogenes specifically with as low as 50 pg/reaction with the naked eye. Through 20 pork samples assay, visual detection assay had the same results as conventional detection methods, and had a good performance. This is a powerful demonstration of the ability of G-quadruplex DNAzyme to be used for PCR-based assay with significant advantages of high sensitivity, low cost and simple manipulation over existing approaches and offers the opportunity for application in pathogen detection.

Listeria monocytogenes is one of the most common pathogenic bacteria. After infection, the main symptoms of listeriosis are sepsis, meningitis and mononucleosis. A G-quadruplex DNAzyme-based LAMP biosensing platform was developed for the colorimetric detection of L. monocytogenes. Four primers were designed to hybridize against six distinct sequences in the target DNA making the highly specific amplification in the step of LAMP. The G-quadruplex sequence amplified simultaneously in LAMP could form DNAzyme with the addition of hemin. The catalytic horseradish peroxidase-mimicking DNAzymes allowed the colorimetric responses of the target DNA from L. monocytogenes. The response surface methodology was used to screen and optimize the crucial factors affecting the response. This assay could detect L. monocytogenes specifically with as low as 47.5 CFU per reaction by the naked eye. Furthermore, this colorimetric detection assay was successfully applied to detect L. monocytogenes in spiked pork samples. Therefore, the rapid, specific and visual detection of L. monocytogenes has demonstrated potentially broad applicability in food safety.

More and more attentions are paid to the potential effect of graphene oxide (GO) in environment and human beings. In order to evaluate the effect of GO on plant, tobacco BY-2 suspension cells were employed as material, and the physiological effect of GO on tobacco BY-2 suspension cells and its immigration were investigated. The results showed that low concentrations of GO (25 and 50 μg/mL) promoted cells growth (increased by 11.22 % in 50 μg/mL GO), while higher concentrations of GO (100 and 200 μg/mL) induced inhibition in cell growth (decreased by 9.68 % in 200 μg/mL GO). GO caused an increment in activity levels of SOD, POD and CAT, but the activity levels decreased with the extension of culture time in higher concentration. The results showed that GO could make cell nuclei fragment and loose in a higher concentration. These results imply that there is an adverse effect of GO on plant cells, and suggest that nano pollution should be paid attention to.

Phospholipase D (PLD) belongs to a large gene family widely found in plants; it can hydrolyze phospholipids to produce phosphatidic acid (PA) and free polar head groups. The PLD family plays an important role in response to various stresses, such as programmed cell death, freezing tolerance, drought and salt tolerance. In this study, a total of 11 PLD genes in Prunus persica were identified, and their expressions patterns under low temperature stress by quantitative real-time PCR were functionally characterized, and determined. The results showed that the chilling injury incidence was not changed significantly in the early stage of low-temperature storage because of some PLD genes involved in freezing tolerance, but it changed significantly during the late stage of low-temperature storage. This was because some PLD genes participated in the degradation of cell membranes during the latter stage. The expression patterns of the 11 PLD genes changed differently during low-temperature conditioning, indicating different functions of the PLD isoforms.

Shanghai has become an international shipping center in the world. In this study, the multiyear measurements and the high resolution air quality model with hourly ship emission inventory were combined to determine the influence of ship emissions on urban Shanghai. The aerosol time-of-flight mass spectrometer (ATOFMS) measurements were carried out at an urban site from April 2009 to January 2013. During the entire sampling time, most of the half-hourly averaged number fractions of primary ship emitted particles varied between 1.0–10.0%. However, the number fraction could reach up to 50% during the ship plume cases. Ship-plume-influenced periods usually occurred in spring and summer. The simulation of Weather Research and Forecasting/Community Multiscale Air Quality model (WRF/CMAQ) with hourly ship emission inventory provided the highly time-resolved concentrations of ship-related air pollutants during a ship plume case. It showed ships could contribute 20–30% (2–7 μg/m3) of the total PM2.5 within tens of ...

Maize chlorotic mottle virus causes corn lethal necrosis disease, and can be transmitted via infected maize seeds. It remains a challenge to detect this virus to prevent its introduction, infection and wide transmission in fields. For this purpose, a colorimetric assay for the detection of Maize chlorotic mottle virus was developed, which utilises RT-LAMP and hydroxynapthol blue dye (HNB). The reaction was performed for amplification in one step in a single tube at the optimum conditions (64 °C for 60 min, 150 μM HNB and 2 mM MgSO4). Samples infected with MCMV developed a characteristic sky blue color after the reaction but those uninfected with MCMV or infected with other plant pathogenic viruses did not. The results of the HNB staining method were reconfirmed through gel electrophoresis of the RT-LAMP products. The sensitivity of this assay was 4.8 pg μl−1 of RNA of Maize chlorotic mottle virus per reaction, which was approximately 10-fold higher sensitivity over a conventional RT-PCR test. The results indicate that this assay is highly species-specific, simple, low-cost, and visual for easy detection of Maize chlorotic mottle virus in plant tissues. Therefore, colorimetric detection of Maize chlorotic mottle virus is a potentially useful tool for middle or small-scale corporations and entry-exit inspection and quarantine bureaus to detect maize seeds or plant tissues infected with Maize chlorotic mottle virus.

Maize chlorotic mottle virus causes corn lethal necrosis disease and can transmit via infected maize seeds. It remains a challenge to detect this virus to prevent its introduction and infection and spread transmission fields. For this purpose, visual detection of Maize chlorotic mottle virus was investigated in cooperation with a asymmetric polymerase chain reaction and unmodified gold nanoparticles (AuNPs). Detection relies on the fact that the dispersed AuNPs solution is red due to the intense surface plasmon absorption band at 520 nm. The color changed to grey after saline induction; single-stranded DNA (ssDNA) electrostatically adsorbed onto naked AuNPs stabilizes them against salt-induced aggregation, whereas the AuNPs solution in the presence of ssDNA of asymmetric RT-PCR target products of Maize chlorotic mottle virus remains red even after saline induction. A remarkable color change from red to grey immediately occurred in absence of ssDNA amplified from Maize chlorotic mottle virus with asymmetric RT-PCR. After optimization of the asymmetric RT-PCR primer ratios, concentration of NaCl, and evaluation of specificity and sensitivity of a novel assay, visual detection of Maize chlorotic mottle virus using unmodified AuNPs and asymmetric RT-PCR has been developed with simple preparation of samples in our study. Through this assay, as low as 23.9 pg μL−1 of RNA of Maize chlorotic mottle virus was detected visually by the naked eye without the need for any sophisticated, expensive instrumentation and biochemical reagents. The results indicate that this assay is highly species-specific, simple, low-cost, and visible for easy detection of Maize chlorotic mottle virus in plant tissues. Therefore, visual detection of Maize chlorotic mottle virus is a potentially useful tool for middle- or small-scale corporations and entry–exit inspection and quarantine bureaux to detect Maize chlorotic mottle virus in maize seeds or plant tissues.

Cronobacter sakazakii is a typical food-borne bacterium that causes clinical symptoms including necrotizing enterocolitis, bacteremia, and meningitis with a mortality rate of 40 %–80 %. In this study, a pair of split G-rich DNA probes was assembled into the DNAzyme capable of mimicking peroxidase. The assembly was utilized to provide a simple, low-cost, highly specific, and sensitive method for rapid detection of viable C. sakazakii. In the absence of viable C. sakazakii, the two split G-rich DNA probes formed DNAzyme, mimicked the activity of peroxidase and displayed colorimetric signals to indicate detection results. In the presence of viable C. sakazakii, specific recognition by the aptamer results in the destruction of the DNAzyme-aptamer complex, and subsequently the colorimetric signal is “turned-off” due to the decrease in DNAzyme bioactivity. Under the optimal reaction conditions, there is a linear relationship between absorption intensity at 418 nm and logarithmic concentration of C. sakazakii in the range of 2–1200 CFU/mL (R2 = 0.9839), with a detection limit of 1.2 CFU/mL. This is the highest sensitivity ever reported for viable C. sakazakii detection. Artificially contaminated samples were assayed by this novel sensor, and numerous advantages were discovered, including ultra-low sensitivity, low-cost, simple operation, and good performance, compared to existing methods. We believe the DNAzyme shows great potential for food safety applications.

Loop-mediated isothermal amplification (LAMP) based on lmo0460 sequence in genome of Listeria monocytogenes (L. monocytogenes) was designed for detection of L. monocytogenes, which is an important foodborne kind of pathogenic bacteria causing human and animal disease. The primers set for lmo0460 sequence encoding membrane-associated lipoprotein consist of four specific primers targeting six regions on specific fragment. The LAMP assay could be optimized and the optimum condition was in 50 min at 63°C. Amplification products were visualized by 2% agarose gel electrophoresis. Sensitivity of the LAMP assay for detection of L. monocytogenes in pure cultures was 1.7 cfu per reaction. The LAMP assay was 147-fold higher sensitive than that of the conventional polymerase chain reaction (PCR) assay (251 cfu/reaction). Fifty chicken samples were detected for L. monocytogenes in the method, and the accuracy of LAMP was shown to be 100% when compared with culture biotechnical, while the PCR assay failed to detect L. monocytogenes in one of the positive samples. It is shown that LAMP assay based on lmo0460 sequence can be a highly sensitive, efficient and easy-to-perform useful detection tool for L. monocytogenes and will be a potential useful and powerful tool for detection foodborne pathogens. Practical Applications L. monocytogenes contamination in chicken samples has been reported. In developing countries, such as China, the LAMP assay is a suitable, useful tool for rapid detection of L. monocytogenes in food because it is more cost-effective, simple and high sensitive than PCR.

Listeria monocytogenes (L. monocytogenes) causes listeriosis in people and animals. After infection, the main symptoms of listeriosis are sepsis, meningitis and mononucleosis. For this purpose, visual detection of L. monocytogenes was developed with unmodified gold nanoparticles. Species-specific probes, in the presence of PCR target products of L. monocytogenes, cause the gold nanoparticles to aggregate irreversibly, producing a red to purple colorimetric change. As little as 1.304 fg µl−1 of DNA of L. monocytogenes were thus detected visually, by the naked eye, without the need for any sophisticated, expensive instrumentation and biochemical reagents, which shows that the method has approximately seventy-fold higher sensitivity than the conventional PCR gel electrophoresis method. The results indicate that this assay is highly species-specific, simple, low-cost, and visual for easy detection of L. monocytogenes.

Helicobacter pylori is a spiral-shaped, Gram-negative, microaerophilic and fastidious bacterium. It is the main cause of chronic gastritis as well as gastric and duodenal ulcers. The diagnosis of H. pylori infection is significant for the selection of therapy and for the follow up of eradication success. A simple and robust strategy based on the cascade of PCR and DNAzyme catalyzed reaction was utilized to detect H. pylori. The design of the primer pair would enable PCR to synthesize aptamer of DNAzyme at the 3' end of PCR products. G-quadruplex DNAzyme as a color label can exhibit peroxidase-like activity to amplify the specific signal and demonstrate a colorimetric signal to indicate the diagnostic result. This assay can detect genomic DNA of H. pylori specifically with as low as 100 pg/reaction by the naked eye. This is a powerful demonstration of G-quadruplex DNAzyme to be used for PCR-based assay with significant advantages of high sensitivity, low cost and simple manipulation over existing approaches and offers the potential opportunity for clinical application.

Our study has identified and analyzed the VvARF gene family that may be associated with the development of grape berry and other tissues. Auxin response factors (ARFs) are transcription factors that regulate the expression of auxin responsive genes through specific binding to auxin response elements (AuxREs). The ARF genes are represented by a large multigene family in plants. Until now, many ARF families have been characterized based on genome resources. However, there is no specialized research about ARF genes in grapevine (Vitis vinifera). In this study, a comprehensive bioinformatics analysis of the grapevine ARF gene family is presented, including chromosomal locations, phylogenetic relationships, gene structures, conserved domains and expression profiles. Nineteen VvARF genes were identified and categorized into four groups (Classes 1, 2, 3 and 4). Most of VvARF proteins contain B3, AUX_RESP and AUX_IAA domains. The VvARF genes were widely expressed in a range of grape tissues, and fruit had higher transcript levels for most VvARFs detected in the EST sources. Furthermore, analysis of expression profiles indicated some VvARF genes may play important roles in the regulation of grape berry maturation processes. This study which provided basic genomic information for the grapevine ARF gene family will be useful in selecting candidate genes related to tissue development in grapevine and pave the way for further functional verification of these VvARF genes.

Maize chlorotic mottle virus (MCMV) infects maize plants and causes significant losses in corn production worldwide. In this study, a real-time TaqMan RT-PCR assay for efficient detection of MCMV was described. A pair of primers amplifying a 131-bp DNA fragment and a TaqMan probe was designed targeting the novel molecular marker based on MCMV genome analysis sequences. The assay designed was highly specific, producing no signal from other viruses, and the sensitivity of the assay was 0.16 fg/reaction of total RNA, which was approximately 252-fold higher than conventional RT-PCR gel electrophoresis method. Compared with the real-time TaqMan reverse transcription PCR targeting coat protein gene, the novel assay has more specificity and sensitivity to detect MCMV in maize. Therefore, the assay is a useful tool for large or middle-scale corporations and entry-exit inspection and quarantine bureau to detect MCMV in maize seeds or plant tissues.

Cucumber green mottle mosaic virus (CGMMV)causes a severe mosaic symptom of watermelon and cucumber, and can be transmitted via infected cucumber seeds, leaves and soil. It remains a challenge to detect this virus to prevent its introduction and infection and spread in fields. For this purpose, a simple and sensitive label-free colorimetric detection method for CGMMV has been developed with unmodified gold nanoparticles (AuNPs) as colorimetric probes. The method is based on the finding that the presence of RT-PCR target products of CGMMV and species-specific probes results in color change of AuNPs from red to blue after NaCl induction. Normally, species-specific probes attach to the surface of AuNPs and thereby increasing their resistance to NaCl-induced aggregation. The concentration of sodium, probes in the reaction system and evaluation of specificity and sensitivity of a novel assay, visual detection of Cucumber green mottle mosaic virus using unmodified AuNPs has been carried out with simple preparation of samples in our study. Through this assay, as low as 30pg/μL of CGMMV RNA was thus detected visually, by the naked eye, without the need for any sophisticated, expensive instrumentation and biochemical reagents. The specificity was 100% and exhibited good reproducibility in our assays. The results note that this assay is highly species-specific, simple, low-cost, and visual for easy detection of CGMMV in plant tissues. Therefore, visual assay is a potentially useful tool for middle or small-scales corporations and entry-exit inspection and quarantine bureau to detect CGMMV in cucumber seeds or plant tissues.

Figures of persimmons for the world's top ten persimmon producing countries are about 4000,000 tons in 2011 and are increasing every year according to FAO statistics. However, there is not any report on pectin production by microbial with persimmon peel as the source. Optimization of fermentation conditions of pectin production from Aspergillus terreus in submerged culture and partial characterization of pectin were carried out in the work. An optimum fermentation condition for pectin production was obtained through a central composite rotatable design in response surface methodology as follows: fermentation time, 30.09 h, temperature, 25.00 °C and the initial pH in the fermentation medium, 6.90, respectively and the pectin yield reached the maximal value 0.449 g/g. Persimmon peel pectin had highly methoxylated (62.51%), high galacturonic acid content (82.28%) than citrus pectin, and was classified as the highly methoxylated pectin, the results indicated that persimmon peel had potential good resources for pectin production. The investigation can make it available to utilize persimmon peel to produce high methoxyl pectin for food industry, pharmacy and cosmetic manufacture.

A strain SHPP01, which produces a protopectinase and has the ability of tannin tolerance, was screened from Shanghai University campus with protopectin as the solo carbon source. It was identified as Aspergillus terreus, and designated as A. terreus SHPP01 based on its morphology and internal transcriptional spacer sequence. Tannin tolerance assay was carried out later to explore the effect on the characters of SHPP01; the result showed the dry weight of A. terreus SHPP01 increased about 1.39 times, when tannin concentration increased from 2 to 10 g/L. With tannin concentration increasing protopectinase production decreased firstly, and increased later, the result showed that tannin concentration below 10 g/L has not significantly affected protopectinase production, and A. terreus SHPP01 has the good ability of tannin tolerance than others in previous literatures. This study provides the foundation to utilize A. terreus SHPP01 to extract pectin from persimmon peel in microbial fermentation. Key words Molecular identification, tannin tolerance, Aspergillus terreus, protopectinase.

The quantitative effects of polyethylene glycol (PEG) 6000 and tripotassium phosphate on protopectinase partition in the aqueous two-phase systems were investigated using response surface methodology. With an increase in PEG 6000 less than about 3.6 g protopectinase partition increased and decreased later beyond about 4.75 g. Furthermore, protopectinase partition improved continually and reached the maximum with the increase of K3PO4 at the range of about 1.40 to 1.70 g, the statistic analysis showed that the effect of PEG (P < 0.0089) had significant effects on protopectinase partition, but the effects of the tripotassium phosphate (P < 0.9475) and the interaction of PEG 6000 and tripotassium phosphate (P < 0.2712) were not significant at the significance level of 0.05. The experimental values were shown to be in good agreement with predicted values since the correlation coefficient was 0.9410. At the optimal partition condition (4.14 g PEG 6000 and 1.71 g tripotassium phosphate in 10 ml two-phase systems), the maximum of protopectinase activity was 17.27 U/ml, which is about 2.27 folds than the other one. Key words: Central composite design (CCD), two-phase systems, polyethylene glycol/tripotassium phosphate, protopectinase partition.

With the research and development of chess robot and machine vision, chess robot with visual function has recently received an increasing interest in the community. This paper introduces the chess system of dual-robot coordination based on vision and the process of visual system structure, gives the coordinates translation from computer and image coordinates to actual coordinates. And in the process of pieces identification, it firstly gives the character segmentation method and training process based on BP neural network, and then identifies the pieces. All the work contributes to the chess system of dual-robot coordination based on vision.