Study of selenium enrichment metabolomics in Bacillus subtilis BSN313 via transcriptome analysis.

In this study, the transcriptome analysis was practiced to identify potential genes of probiotic Bacillus subtilis BSN313 involved in selenium (Se) enrichment metabolism. The transcriptomic variation of the strain was deliberated in presence of three different sodium selenite concentrations (0, 3, and 20 µg/mL). The samples were taken at 1 and 13 h subsequent to inoculation of selenite and gene expression profiles in Se metabolism were analyzed through RNA sequencing. The gene expression levels of the pre log phase were lower than the stationary phase. It is because, the bacteria has maximum grown with high concentration of Se (enriched with organic Se), at stationary phase. Bacterial culture containing 3 µg/mL concentration of inorganic Se (sodium selenite) has shown highest gene expression as compared to no or high concentration of Se. This concentration (3 µg/mL) of sodium selenite (as Se) in the medium promoted the upregulation of thioredoxin reductase expression, whereas its higher Se concentration inhibited the formation of selenomethionine (SeMet). The result of 5 L bioreactor fermentation showed that SeMet was also detected in the fermentation supernatant as the growth entered in the late stationary phase and reached up to 857.3 ng/mL. The overall intracellular SeMet enriched content in BSN313 was extended up to 23.4 µg/g dry cell weight. The other two selenoamino acids (Se-AAs), methyl-selenocysteine, and selenocysteine were hardly detected in medium supernatant. From this study, it was concluded that SeMet was the highest content of organic Se byproduct biosynthesized by B. subtilis BSN313 strain in Se-enriched medium during stationary phase. Thus, B. subtilis BSN313 can be considered a commercial probiotic strain that can be used in the food and pharmaceutical industries. This is because it can meet the commercial demand for Se-AAs (SeMet) in both industries.

Development and validation of a 23-gene expression signature for molecular subtyping of medulloblastoma in a long-term Chinese cohort.

PURPOSE: Medulloblastoma is the most common childhood malignant brain tumor and is a leading cause of cancer-related death in children. Recent transcriptional studies have shown that medulloblastomas comprise at least four molecular subgroups, each with distinct demographics, genetics, and clinical outcomes. Medulloblastoma subtyping has become critical for subgroup-specific therapies. The use of gene expression assays to determine the molecular subgroup of clinical specimens is a long-awaited application of molecular biology for this pediatric cancer. METHODS: In the current study, we established a medulloblastoma transcriptome database of 460 samples retrieved from three published datasets (GSE21140, GSE37382, and GSE37418). With this database, we identified a 23-gene signature that is significantly associated with the medulloblastoma subgroups and achieved a classification accuracy of 95.2%. RESULTS: The 23-gene signature was further validated in a long-term cohort of 142 Chinese medulloblastoma patients. The 23-gene signature classified 21 patients as WNT (15%), 41 as SHH (29%), 16 as Group 3 (11%), and 64 as Group 4 (45%). For patients of WNT, SHH, Group 3, and Group 4, 5-year overall-survival rate reached 80%, 62%, 27%, and 47%, respectively (p < 0.0001), meanwhile 5-year progression-free survival reached 80%, 52%, 27%, and 45%, respectively (p < 0.0001). Besides, SHH/TP53-mutant tumors were associated with worse prognosis compared with SHH/TP53 wild-type tumors and other subgroups. We demonstrated that subgroup assignments by the 23-gene signature and Northcott's NanoString assay were highly comparable with a concordance rate of 96.4%. CONCLUSIONS: In conclusion, we present a novel gene signature that is capable of accurately and reliably assigning FFPE medulloblastoma samples to their molecular subgroup, which may serve as an auxiliary tool for medulloblastoma subtyping in the clinic. Future incorporation of this gene signature into prospective clinical trials is warranted to further evaluate its clinical.

Optimized methyl donor and reduced precursor degradation pathway for seleno-methylselenocysteine production in Bacillus subtilis.

BACKGROUND: Seleno-methylselenocysteine (SeMCys) is an effective component of selenium supplementation with anti-carcinogenic potential that can ameliorate neuropathology and cognitive deficits. In a previous study, a SeMCys producing strain of Bacillus subtilis GBACB was generated by releasing feedback inhibition by overexpression of cysteine-insensitive serine O-acetyltransferase, enhancing the synthesis of S-adenosylmethionine as methyl donor by overexpression of S-adenosylmethionine synthetase, and expressing heterologous selenocysteine methyltransferase. In this study, we aimed to improve GBACB SeMCys production by synthesizing methylmethionine as a donor to methylate selenocysteine and by inhibiting the precursor degradation pathway. RESULTS: First, the performance of three methionine S-methyltransferases that provide methylmethionine as a methyl donor for SeMCys production was determined. Integration of the NmMmt gene into GBACB improved SeMCys production from 20.7 to 687.4 µg/L. Next, the major routes for the degradation of selenocysteine, which is the precursor of SeMCys, were revealed by comparing selenocysteine hyper-accumulating and non-producing strains at the transcriptional level. The iscSB knockout strain doubled SeMCys production. Moreover, deleting sdaA, which is responsible for the degradation of serine as a precursor of selenocysteine, enhanced SeMCys production to 4120.3 µg/L. Finally, the culture conditions in the flasks were optimized. The strain was tolerant to higher selenite content in the liquid medium and the titer of SeMCys reached 7.5 mg/L. CONCLUSIONS: The significance of methylmethionine as a methyl donor for SeMCys production in B. subtilis is reported, and enhanced precursor supply facilitates SeMCys synthesis. The results represent the highest SeMCys production to date and provide insight into Se metabolism.

Enhanced selenocysteine biosynthesis for seleno-methylselenocysteine production in Bacillus subtilis.

Seleno-methylselenocysteine (SeMCys) is an effective component for selenium supplementation with anti-carcinogenic potential and can ameliorate neuropathology and cognitive deficits. In this study, we aimed to engineer Bacillus subtilis 168 for the microbial production of SeMCys. First, the accumulation of intracellular selenocysteine (SeCys) as the precursor of SeMCys was enhanced through overexpression of serine O-acetyltransferase, which was desensitized against feedback inhibition by cysteine. Next, the S-adenosylmethionine (SAM) synthetic pathway was optimized to improve methyl donor availability through expression of S-adenosylmethionine synthetase. Further, SeMCys was successfully produced through expression of the selenocysteine methyltransferase in SeCys and SAM-producing strain. The increased expression level of selenocysteine methyltransferase benefited the SeMCys production. Finally, all the heterologous genes were integrated into the genome of B. subtilis, and the strain produced SeMCys at a titer of 18.4 µg/L in fed-batch culture. This is the first report on the metabolic engineering of B. subtilis for microbial production of SeMCys and provides a good starting point for future pathway engineering to achieve the industrial-grade production of SeMCys. KEY POINTS: • Expression of the feedback-insensitive serine O-acetyltransferase provided B. subtilis the ability of accumulating SeCys. • SAM production was enhanced through expressing S-adenosylmethionine synthetase in B. subtilis. • Expression of selenocysteine methyltransferase in SeCys and SAM-accumulating strain facilitated SeMCys production.

Purification, Characterization and Bactericidal Action of Lysozyme, Isolated from Bacillus subtillis BSN314: A Disintegrating Effect of Lysozyme on Gram-Positive and Gram-Negative Bacteria.

In the present study, lysozyme was purified by the following multi-step methodology: salt (ammonium sulfate) precipitation, dialysis, and ultrafiltration. The lysozyme potential was measured by enzymatic activity after each purification step. However, after ultrafiltration, the resulting material was considered extra purified. It was concentrated in an ultrafiltration centrifuge tube, and the resulting protein/lysozyme was used to determine its bactericidal potential against five bacterial strains, including three gram-positive (Bacillus subtilis 168, Micrococcus luteus, and Bacillus cereus) and two gram-negative (Salmonella typhimurium and Pseudomonas aeruginosa) strains. The results of ZOI and MIC/MBC showed that lysozyme had a higher antimicrobial activity against gram-positive than gram-negative bacterial strains. The results of the antibacterial activity of lysozyme were compared with those of ciprofloxacin (antibiotic). For this purpose, two indices were applied in the present study: antimicrobial index (AMI) and percent activity index (PAI). It was found that the purified lysozyme had a higher antibacterial activity against Bacillus cereus (AMI/PAI; 1.01/101) and Bacillus subtilis 168 (AMI/PAI; 1.03/103), compared to the antibiotic (ciprofloxacin) used in this study. Atomic force microscopy (AFM) was used to determine the bactericidal action of the lysozyme on the bacterial cell. The purified protein was further processed by gel column chromatography and the eluate was collected, its enzymatic activity was 21.93 U/mL, while the eluate was processed by native-PAGE. By this analysis, the un-denatured protein with enzymatic activity of 40.9 U/mL was obtained. This step shows that the protein (lysozyme) has an even higher enzymatic potential. To determine the specific peptides (in lysozyme) that may cause the bactericidal potential and cell lytic/enzymatic activity, the isolated protein (lysozyme) was further processed by the SDS-PAGE technique. SDS-PAGE analysis revealed different bands with sizes of 34 kDa, 24 kDa, and 10 kDa, respectively. To determine the chemical composition of the peptides, the bands (from SDS-PAGE) were cut, enzymatically digested, desalted, and analyzed by LC-MS (liquid chromatography-mass spectrometry). LC-MS analysis showed that the purified lysozyme had the following composition: the number of proteins in the sample was 56, the number of peptides was 124, and the number of PSMs (peptide spectrum matches) was 309. Among them, two peptides related to lysozyme and bactericidal activities were identified as: A0A1Q9G213 (N-acetylmuramoyl-L-alanine amidase) and A0A1Q9FRD3 (D-alanyl-D-alanine carboxypeptidase). The corresponding protein sequence and nucleic acid sequence were determined by comparison with the database.

Myostain is involved in ginsenoside Rb1-mediated anti-obesity.

CONTEXT: Obesity, one of the major public health problems worldwide, has attracted increasing attention. Ginsenoside Rb1 is the most abundant active component of Panax ginseng C.A.Mey (Araliaceae) and is reported to have beneficial effects on obesity and diabetes. However, the mechanisms by which Rb1 regulates obesity remain to be explored. OBJECTIVE: This paper intends to further explore the mechanism of Rb1 in regulating obesity. MATERIALS AND METHODS: The C57BL/6 obese mice were divided into two groups: the control (CTR) and Rb1. The CTR group [intraperitoneally (ip) administered with saline] and the Rb1 group (ip administered with Rb1, 40 mg/kg/d) were treated daily for four weeks. In vitro, Rb1 (0, 10, 20, 40 µM) was added to differentiated C2C12 cells and Rb1 (0, 20, 40 µM) was added to 3T3-L1 cells. After 24 h, total RNA and protein from C2C12 cells and 3T3-L1 cells were used to detect myostatin (MSTN) and fibronectin type III domain-containing 5 (FNDC5) expression. RESULTS: Rb1 reduced the body weight and adipocyte size. Improved glucose tolerance and increased basic metabolic activity were also found in Rb1 treated mice. MSTN was downregulated in differentiated C2C12 cells, 3T3-L1 cells and adipose tissues upon Rb1 treatment. FNDC5 was increased after Rb1 treatment. However, MSTN overexpression attenuated Rb1-mediated decrease accumulation of lipid droplets in differentiated 3T3-L1 adipocytes. DISCUSSION & CONCLUSIONS: Rb1 may ameliorate obesity in part through the MSTN/FNDC5 signalling pathway. Our results showed that Rb1 can be used as an effective drug in the treatment of human obesity.

Quantum simulation of tunable and ultrastrong mixed-optomechanics.

We propose a reliable scheme to simulate tunable and ultrastrong mixed (first-order and quadratic optomechanical couplings coexisting) optomechanical interactions in a coupled two-mode bosonic system, in which the two modes are coupled by a cross-Kerr interaction and one of the two modes is driven through both the single- and two-excitation processes. We show that the mixed-optomechanical interactions can enter the single-photon strong-coupling and even ultrastrong-coupling regimes. The strengths of both the first-order and quadratic optomechanical couplings can be controlled on demand, and hence first-order, quadratic, and mixed optomechanical models can be realized. In particular, the thermal noise of the driven mode can be suppressed totally by introducing a proper squeezed vacuum bath. We also study how to generate the superposition of coherent squeezed state and vacuum state based on the simulated interactions. The quantum coherence effect in the generated states is characterized by calculating the Wigner function in both the closed- and open-system cases. This work will pave the way to the observation and application of ultrastrong optomechanical effects in quantum simulators.

Biosynthesis of Selenium Nanoparticles (via Bacillus subtilis BSN313), and Their Isolation, Characterization, and Bioactivities.

Among the trace elements, selenium (Se) has great demand as a health supplement. Compared to its other forms, selenium nanoparticles have minor toxicity, superior reactivity, and excellent bioavailability. The present study was conducted to produce selenium nanoparticles (SeNPs) via a biosynthetic approach using probiotic Bacillus subtilis BSN313 in an economical and easy manner. The BSN313 exhibited a gradual increase in Se reduction and production of SeNPs up to 5-200 µg/mL of its environmental Se. However, the capability was decreased beyond that concentration. The capacity for extracellular SeNP production was evidenced by the emergence of red color, then confirmed by a microscopic approach. Produced SeNPs were purified, freeze-dried, and subsequently characterized systematically using UV-Vis spectroscopy, FTIR, Zetasizer, SEM-EDS, and TEM techniques. SEM-EDS analysis proved the presence of selenium as the foremost constituent of SeNPs. With an average particle size of 530 nm, SeNPs were shown to have a -26.9 (mV) zeta potential and -2.11 µm cm/Vs electrophoretic mobility in water. SeNPs produced during both the 24 and 48 h incubation periods showed good antioxidant activity in terms of DPPH and ABST scavenging action at a concentration of 150 µg/mL with no significant differences (p > 0.05). Moreover, 200 µg/mL of SeNPs showed antibacterial reactivity against Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 9027, and Pseudomonas aeruginosa ATCC 25923. In the future, this work will be helpful to produce biogenic SeNPs using probiotic Bacillus subtilis BSN313 as biofactories, with the potential for safe use in biomedical and nutritional applications.

Coordination-Driven Stereospecific Control Strategy for Pure Cycloisomers in Solid-State Diene Photocycloaddition.

To obtain a pure product without the isomer byproducts is a goal that many chemists are pursuing. As one kind of very important synthesis method, the photochemical reaction is simple and straightforward yet low-selective. In this work, a coordination interaction-based oriented synthesis strategy has been proposed to realize the precise stereochemical control of the isomeric cyclic compounds in the photocycloaddition reaction. Through fixing the reactants via coordination interactions, the arrangements and configurations of the reactants can be adjusted, thereby successfully producing all of the related photocycloaddition products without isomer byproducts for the first time. This work not only provides a new route to synthesize the pure cyclic compounds but also expands the application of the photocycloaddition reaction.

Fiber laser spot welding of molybdenum alloy in a hyperbaric environment.

The effect of the growth of ambient pressures on the penetration of laser welded molybdenum (Mo) alloy was explored. It was found that when ambient pressure rose from 0.1 MPa to 1.8 MPa, the penetration of base metal (BM) was significantly reduced, which was only 17% of that obtained under ambient pressure of 0.1 MPa. Moreover, the mechanism underlying the significant reduction of the penetration of BM was analyzed. At first, by using a high-resolution scanning electron microscope (SEM), the size and the number of nano-sized metallic particles generated during laser welding under different ambient pressures were surveyed. Furthermore, the scattering and absorption of the nano-sized metallic particles for laser energy under different ambient pressures were investigated; afterwards, by applying a high-speed camera and a spectrometer, the transient behaviors and spectral signals of plasmas during fiber laser spot welding under different ambient pressures were monitored. On this basis, the inverse bremsstrahlung absorption of plasmas for laser energy under different ambient pressures was explored; finally, fiber laser spot welding test was carried out on glass/metal composite samples under different ambient pressures to survey the influence of the change of ambient pressure on dynamic behaviors of the molten pool during the welding.

Comparison of high-resolution synchrotron-radiation-based phase-contrast imaging and absorption-contrast imaging for evaluating microstructure of vascular networks in rat brain: from 2D to 3D views.

Conventional imaging methods such as magnetic resonance imaging, computed tomography and digital subtraction angiography have limited temporospatial resolutions and shortcomings like invasive angiography, potential allergy to contrast agents, and image deformation, that restrict their application in high-resolution visualization of the structure of microvessels. In this study, through comparing synchrotron radiation (SR) absorption-contrast imaging to absorption phase-contrast imaging, it was found that SR-based phase-contrast imaging could provide more detailed ultra-high-pixel images of microvascular networks than absorption phase-contrast imaging. Simultaneously, SR-based phase-contrast imaging was used to perform high-quality, multi-dimensional and multi-scale imaging of rat brain angioarchitecture. With the aid of image post-processing, high-pixel-size two-dimensional virtual slices can be obtained without sectioning. The distribution of blood supply is in accordance with the results of traditional tissue staining. Three-dimensional anatomical maps of cerebral angioarchitecture can also be acquired. Functional partitions of regions of interest are reproduced in the reconstructed rat cerebral vascular networks. Imaging analysis of the same sample can also be displayed simultaneously in two- and three-dimensional views, which provides abundant anatomical information together with parenchyma and vessels. In conclusion, SR-based phase-contrast imaging holds great promise for visualizing microstructure of microvascular networks in two- and three-dimensional perspectives during the development of neurovascular diseases.

Pace capture and adenosine triphosphate provocation are complementary rather than mutually exclusive methods to ensure durable pulmonary vein isolation.

INTRODUCTION: Adenosine triphosphate (ATP)-provoked dormant conduction (DC) and pacing for unexcitability are used to identify conduction gaps along the ablation lines after circumferential pulmonary vein isolation (CPVI). We aim to determine whether ATP provocation and pacing are interchangeable as endpoints for ablation of paroxysmal atrial fibrillation (PAF). METHODS AND RESULTS: A total of 107 patients with PAF were randomly divided into two groups after completion of CPVI. In group I (A-P group, n = 53), ATP was administered first. If DC was uncovered, additional ablation was performed until ATP tests were negative. Bipolar pacing along the ablation line was performed subsequently. In group II (P-A group, n = 54), the same protocol was used, but the pacing and the ATP tests were performed in the opposite sequence. The 12-month ablation outcomes of all patients were compared with those of a historical control group of 107 patients with PAF in whom only ATP test was performed. Regardless of which test was performed first, the other modality still identified conduction gaps. In group I, pacing maneuvers identified gaps in 49% (n = 26) of patients who had negative ATP tests. In group II, ATP tests uncovered DC in 18.5% (n = 10) of patients in whom pacing identified no gaps. After 12 months, a higher proportion of patients (91.6%) were free from atrial tachyarrhythmias compared with the historical control group (81.3%; P = 0.031). CONCLUSION: Pacing along the ablation lines and ATP provocation are complementary tests for evaluating the durability of CPVI and can lead to better long-term outcomes when used in combination.

Oxidation of Sodium Deoxycholate Catalyzed by Gold Nanoparticles and Chiral Recognition Performances of Bile Salt Micelles.

Au nanoparticles (NPs) were prepared by UV light irradiation of a mixed solution of HAuCl4 and sodium deoxycholate (NaDC) under alkaline condition, in which NaDC served as both reducing agent and capping agent. The reaction was monitored by circular dichroism (CD) spectra, and it was found that the formed gold NPs could catalyze the oxidation of NaDC. A CD signal at ~283 nm in the UV region was observed for the oxidation product of NaDC. The intensity of the CD signal of the oxidation product was enhanced gradually with the reaction time. Electrospray ionization (ESI) mass spectra and nuclear magnetic resonance (NMR) spectra were carried out to determine the chemical composition of the oxidation product, revealing that NaDC was selectively oxidized to sodium 3-keto-12-hydroxy-cholanate (3-KHC). The chiral discrimination abilities of the micelles of NaDC and its oxidation product, 3-KHC, were investigated by using chiral model molecules R,S-1,1'-Binaphthyl-2,2'-diyl hydrogenphosphate (R,S-BNDHP). Compared with NaDC, the micelles of 3-KHC displayed higher binding ability to the chiral model molecules. In addition, the difference in binding affinity of 3-KHC micelles towards R,S-isomer was observed, and S-isomer was shown to preferentially bind to the micelles.

[Research on contents of anthraquinones,dianthrones and tannins in Rheum tanguticum on PCA and CA].

Anthraquinones,dianthrones and tannins are the main active ingredients of Rheum tanguticum. In this study the three components were determined by HPLC,and the results were analyzed by multiple comparisons,principal components analysis(PCA)and correspondence analysis(CA). The results showed that the contents of components in different growing areas and types(wild and cultivated) reached a significant level(P<0. 05). Baiyu county,Xiaojin county and Ruoergai county had obvious advantages in the accumulation of catechin hydrate,rhien and sensenoside A respectively. The principal component was different in two growing type and the wild environment was conducive to combined anthraquinones accumulation. For active components,normalized planting was better than retail cultivating. Therefore,the effect on the accumulation of chemical components in Rh. tangusticum,should be taken into full account in the selection of the cultural base of Rh. tanguticum. The standardized cultivating is superior to retail cultivating in terms of the accumulation of active ingredients,and standardized planting is inferior to the wild.

Pgas, a Low-pH-Induced Promoter, as a Tool for Dynamic Control of Gene Expression for Metabolic Engineering of Aspergillus niger.

The dynamic control of gene expression is important for adjusting fluxes in order to obtain desired products and achieve appropriate cell growth, particularly when the synthesis of a desired product drains metabolites required for cell growth. For dynamic gene expression, a promoter responsive to a particular environmental stressor is vital. Here, we report a low-pH-inducible promoter, Pgas, which promotes minimal gene expression at pH values above 5.0 but functions efficiently at low pHs, such as pH 2.0. First, we performed a transcriptional analysis of Aspergillus niger, an excellent platform for the production of organic acids, and we found that the promoter Pgas may act efficiently at low pH. Then, a gene for synthetic green fluorescent protein (sGFP) was successfully expressed by Pgas at pH 2.0, verifying the results of the transcriptional analysis. Next, Pgas was used to express the cis-aconitate decarboxylase (cad) gene of Aspergillus terreus in A. niger, allowing the production of itaconic acid at a titer of 4.92 g/liter. Finally, we found that Pgas strength was independent of acid type and acid ion concentration, showing dependence on pH only.IMPORTANCE The promoter Pgas can be used for the dynamic control of gene expression in A. niger for metabolic engineering to produce organic acids. This promoter may also be a candidate tool for genetic engineering.

Association analyses identify two susceptibility loci 5q31 and 5q22.1 for atopic dermatitis in Chinese Han population.

BACKGROUND: Atopic dermatitis (AD) and other atopic diseases often share some common genetic and pathogenic bases. Recent genome-wide association studies (GWAS) have identified several loci associated with atopic diseases, allergic sensitization and asthma in different populations. The aim of this study was to investigate whether these susceptibility loci were related to AD in Chinese Han population. METHODS: Eight single nucleotide polymorphisms (SNPs) from recent atopic diseases and allergic sensitization GWAS were genotyped in 3,013 AD patients and 5,483 healthy controls in Chinese Han population using Sequenom MassArray system. Data was analyzed with PLINK 1.07 software. RESULTS: We identified that the susceptibility loci at 5q31 (RAD50/IL13, rs2158177, P = 1.08×10-3, OR = 1.15) and 5q22.1 (TSLP, rs1837253, P = 2.66×10-3, OR = 0.91) were significantly associated with AD. Genotype-based association testing revealed that the dominant model provided the best fit for both rs2158177 (P = 3.75×10-3) and rs1837253 (P = 5.30×10-3). Pathway analysis conformed that both loci were associated with the JAK-STAT signaling pathway. CONCLUSIONS: We identified two susceptibility loci 5q31 and 5q22.1 for AD that might bear candidate genes conferring susceptibility to AD.

Study on COD removal mechanism and reaction kinetics of oilfield wastewater.

The chemical oxygen demand (COD) removal mechanism and reaction kinetics were mainly studied in the treatment of oilfield oily sewage containing polymer by three-dimensional electrode reactor. The results proved that the residual active oxides O3, H2O2, •OH and active chlorine in the system of electrochemical reaction could be effectively detected, and the COD removal mechanism was co-oxidation of active oxides; Under these experimental conditions: the electrolysis current of 6 A, surface/volume ratio of 6/25(cm2·L-1), the reaction time of 50 min, the CODcr of treated sewage was no more than 50 mg·L-1; the removal reaction of COD conformed to apparent second-order reaction kinetic model, the correlation coefficient R2 was 0.9728, and the apparent reaction rate constant was k = 3.58 × 10-4 (L·min-1·mg-1·m-2). To reach the goal, the CODcr was no more than 50 mg·L-1 in treated sewage, and the theory minimum processing time was 45.73 min. The verification of experimental results was consistent with kinetic equations.

Discrimination of GMOs Using Terahertz Spectroscopy and CS-SVM.

This paper develops an effective identification method to discriminate genetically modified (GM) and non-GM organisms. The method is proposed based on terahertz (THz) spectroscopy and support vector machines optimized by Cuckoo Search algorithm (CS-SVM). In this study, the THz spectra of three GM and non-GM soya seed samples were obtained by using terahertz time-domain spectroscopy (THz-TDS) system between 0.2 and 1.2 THz. Then, the SVM model is employed to distinguish GM and non-GM soya seeds, in which the two crucial parameters, including the penalty factor and kernel parameter, are optimized by CS algorithm. The experimental results show that THz spectroscopy combined with CS-SVM can provide a rapid, reliable and non-invasive method for GMOs and non-GMOs discrimination.