Portable multichannel detection instrument based on time-resolved fluorescence immunochromatographic test strip for on-site detecting pesticide residues in vegetables.

In this work, a portable multichannel detection instrument based on time-resolved fluorescence immunochromatographic test strip (TRFIS) was proposed for on-site detecting pesticide residues in vegetables. Its hardware consisted of a silicon photodiode and excitation light source array, a mainboard of the lower machine with STMicroelectronics 32 (STM32) and a linear stepping motor. While detecting, cardboard with 6-channel TRFIS was pulled into the cassette by the stepping motor. The peak area of the test (T) line and control (C) line of each TRFIS was sampled and calculated by software, then the concentration of the detected pesticide was obtained according to the ratio of the T to C value. This instrument could sample 6-channel TRFIS within 30 s simultaneously, and it exhibited excellent accuracy with a 2.5% average coefficient of variation for each channel (n = 12). In addition, the TRFIS was constructed by using europium oxide time-resolved fluorescent microspheres to label the monoclonal antibody against acetamiprid and form a fluorescent probe, which was fixed on the binding pad. The TRFIS was used for the detection of acetamiprid in celery cabbage, cauliflower and baby cabbage. This instrument was used to complete the qualitative and quantitative analysis of the TRFIS, so as to enhance the practical application of the detection method. This TRFIS possessed excellent linearity ranging from 0.25 mg kg-1 to 1.75 mg kg-1 for the detection of acetamiprid, and the limit of detection were 0.056-0.074 mg kg-1 in the different vegetable matrix. The platform combines the accuracy and portability of traditional test strips with the highly sensitive and efficient fluorescence intensity recognition function of detection equipment, which shows a great application prospect of multi-channel rapid detection of small molecule pollutants in the field.

Paper-based biosensors relying on core biological immune scaffolds for the detection of procymidone in vegetables.

In order to achieve a highly sensitive detection of procymidone in vegetables, three paper-based biosensors based on a core biological immune scaffold (CBIS) were developed, which were time-resolved fluorescence immunochromatography strips with Europium (III) oxide (Eu-TRFICS). Goat anti-mouse IgG and europium oxide time-resolved fluorescent microspheres formed secondary fluorescent probes. CBIS was formed by secondary fluorescent probes and procymidone monoclonal antibody (PCM-Ab). The first type of Eu-TRFICS (Eu-TRFICS-(1)) fixed secondary fluorescent probes on a conjugate pad, and PCM-Ab was mixed with a sample solution. The second type of Eu-TRFICS (Eu-TRFICS-(2)) fixed CBIS on the conjugate pad. The third type of Eu-TRFICS (Eu-TRFICS-(3)) was directly mixed CBIS with the sample solution. They solved the problems of steric hindrance of antibody labeling, insufficient exposure of antigen recognition region and easy loss of activity in traditional methods. They realized multi-dimensional labeling and directional coupling. They replaced the loss of antibody activity. And the three types of Eu-TRFICS were compared, among which Eu-TRFICS-(1) was the best detection choice. Antibody usage was reduced by 25% and sensitivity was increased by 3 times. Its detection range was 1-800 ng/mL, the limit of detection (LOD) was 0.12 ng/mL with the visible LOD (vLOD) of 5 ng/mL.

Loop-Mediated Isothermal Amplification (LAMP) as a Rapid, Affordable and Effective Tool to Involve Students in Undergraduate Research.

Undergraduate research (UR) is a high-impact practice (HIP) to engage undergraduate student in science, technology, engineering and mathematics (STEM), especially from underrepresented groups. UR experiences (UREs) can be integrated into the classroom, making authentic research experiences inclusive and available to all students. However, developing UR pedagogy can be challenging for faculty in resource-limited labs, such as community colleges and small liberal arts colleges. Often molecular biology research methods are expensive, time-consuming and need equipment not readily available or affordable in small schools. Polymerase chain reaction (PCR) is one of the most commonly used techniques in research labs and many UREs. We have investigated loop-mediated isothermal amplification (LAMP) as an inexpensive, accessible alternative to PCR for DNA amplification enabling the identification of microorganisms in the context of UREs. LAMP does not require expensive instrumentation or reagents and uses equipment commonly found in teaching labs. By performing the technique, students learn several key scientific skills that will be useful in their undergraduate or graduate STEM careers. We designed guided independent research experiences for several undergraduates that included the use of LAMP. Students successfully applied the technique to culture samples of common environmental bacteria, including Escherichia coli, Salmonella spp., Staphylococcus aureus, and Enterococcus, and were in addition, able to detect both Salmonella and Enterococcus in directly sampled environmental waters. To highlight the accessibility and affordability of this URE, a simple boiling method was used for DNA preparation from environmental samples. Student response data show positive attitudes toward UR when LAMP is utilized as a research tool to tackle relevant biological questions. The feasibility of using simplified LAMP in UREs points to a potential, more expanded application to public engagement with science and broader and more inclusive interactions with the research community.

Chromatin remodeling complexes are involvesd in the regulation of ethanol production during static fermentation in budding yeast.

The budding yeast Saccharomyces cerevisiae remains a central position among biofuel-producing organisms. However, the gene expression regulatory networks behind the ethanol fermentation is still not fully understood. Using a static fermentation model, we have examined the ethanol yields on biomass of deletion mutants for all yeast nonessential genes encoding transcription factors and their related proteins in the yeast genome. A total of 20 (about 10%) transcription factors are identified to be regulators of ethanol production during fermentation. These transcription factors are mainly involved in cell cycling, chromatin remodeling, transcription, stress response, protein synthesis and lipid synthesis. Our data provides a basis for further understanding mechanisms regulating ethanol production in budding yeast.

[Association between severe preeclampsia and single nucleotide polymorphism of macrophage migration inhibitory factors -173G/C].

OBJECTIVE: To investigate whether single nucleotide polymorphism (SNP) of macrophage migration inhibitory factor (MIF) gene -173G/C is associated with severe preeclampsia. METHODS: Totally 124 severe preeclampsia patients and 160 healthy pregnant women (control group) were included in our study who were recruited consecutively from Affiliated Hospital of Qingdao University Medical College between March 2010 and March 2011. The SNP was detected through SYBR Green PCR. The levels of fasting blood glucose (FBG), fasting insulin (FIN), and serum total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL) and light density lipoprotein (LDL) were determined in every participants. The homeostasis model assessment-insulin resistance (HOMA-IR) was calculated. The allele and genotype frequencies between severe preeclampsia patients and control group were compared. The FBG, FIN, body mass index (BMI), HOMA-IR, TC, TG, HDL and LDL in different genotype were compared. RESULTS: (1) The MIF -173G/C SNP genotype frequencies of GG, CG, and CC were 62.1% (77/124), 30.6% (38/124), 7.3% (9/124), the allelic frequencies of G and C were 77.4% (192/248) and 22.6% (56/248), respectively, in severe preeclampsia patients; the MIF -173G/C SNP genotype frequencies of GG, CG, and CC were 64.4% (103/160), 30.6% (49/160), 5.0% (8/160), the allelic frequencies of G and C were 79.7% (255/320) and 20.3% (65/320), respectively, in the control group. No significant differences were observed in the genotypes and allele distributions of MIF -173G/C SNP between the severe preeclampsia patients and control group (all P > 0.05). (2) The severe preeclampsia patients with CG and CC genotypes had higher BMI compared with the GG genotype [(25 ± 4) versus (22 ± 4) kg/m(2); t = 3.96, P < 0.05].(3) The severe preeclampsia patients with CG and CC genotypes had higher FIN level and higher HOMA-IR compared with the GG genotype [(15.7 ± 2.9) versus (13.6 ± 4.0) mmol/L, 3.3 ± 0.5 versus 2.7 ± 0.6; t = 3.17, t = 5.58, all P < 0.05]. (4) There was no significant difference in FBG, TC, TG, HDL and LDL levels in severe preeclampsia patients with different genotypes (all P > 0.05). CONCLUSIONS: The present study suggests that the MIF -173G/C SNP is associated with insulin resistance in severe preeclampsia patients. The CG and CC genotypes increase the degree of insulin resistance, but it is may not associate with susceptibility among severe preeclampsia patients of Han Chinese women.