Transcription factor OsbZIP10 modulates rice grain quality by regulating OsGIF1.

Understanding and optimizing the process of grain filling helps the quest to maximize rice (Oryza sativa L.) seed yield and quality, yet the intricate mechanisms at play remain fragmented. Transcription factors (TFs) are major players in the gene networks underlying the grain filling process. Here, we employed grain incomplete filling (OsGIF1)/cell wall invertase 2, a key gene involved in grain filling, to explore its upstream TFs and identified a bZIP family TF, OsbZIP10, to be a transcriptional activator of OsGIF1. Rice grains of the knockouts of OsbZIP10 showed increased white-core rates but lower amylose content (AC), leading to better eating and cooking qualities in all genetic backgrounds investigated, though the impact of mutations in OsbZIP10 on grain weight depended on genetic background. Multi-omics analyses suggested that, in addition to OsGIF1, multiple genes involved in different biological processes contributing to grain filling were targeted by OsbZIP10, including OsAGPS1, a gene encoding the ADP-Glc pyrophosphorylase (AGPase) small subunit, and genes contributing to homeostasis of reactive oxygen species. Distinct genetic make-up was observed in OsbZIP10 between japonica and indica rice varieties, with the majority varieties of each subspecies belonging to two different haplotypes that were closely associated with AC. Overexpressing the haplotype linked to high-AC in the low-AC genetic background increased AC. Overall, this study sheds crucial light on the significance of the OsbZIP10-OsGIF1 module in the determination of rice grain quality, offering a potential avenue for genetic engineering of rice to produce seeds with tailored attributes.

OsNAC5 orchestrates OsABI5 to fine-tune cold tolerance in rice.

Due to its tropical origins, rice (Oryza sativa) is susceptible to cold stress, which poses severe threats to production. OsNAC5, a NAC-type transcription factor, participates in the cold stress response of rice, but the detailed mechanisms remain poorly understood. Here, we demonstrate that OsNAC5 positively regulates cold tolerance at germination and in seedlings by directly activating the expression of ABSCISIC ACID INSENSITIVE 5 (OsABI5). Haplotype analysis indicated that single nucleotide polymorphisms in a NAC-binding site in the OsABI5 promoter are strongly associated with cold tolerance. OsNAC5 also enhanced OsABI5 stability, thus regulating the expression of cold-responsive (COR) genes, enabling fine-tuned control of OsABI5 action for rapid, precise plant responses to cold stress. DNA affinity purification sequencing coupled with transcriptome deep sequencing identified several OsABI5 target genes involved in COR expression, including DEHYDRATION-RESPONSIVE ELEMENT BINDING FACTOR 1A (OsDREB1A), OsMYB20, and PEROXIDASE 70 (OsPRX70). In vivo and in vitro analyses suggested that OsABI5 positively regulates COR gene transcription, with marked COR upregulation in OsNAC5-overexpressing lines and downregulation in osnac5 and/or osabi5 knockout mutants. This study extends our understanding of cold tolerance regulation via OsNAC5 through the OsABI5-CORs transcription module, which may be used to ameliorate cold tolerance in rice via advanced breeding.

OsSGT1 promotes melatonin-ameliorated seed tolerance to chromium stress by affecting the OsABI5-OsAPX1 transcriptional module in rice.

Chromium (Cr) pollution threatens plant development and growth. Application of melatonin (Mel) is emerging as an effective ally to resist stress, but how Mel ameliorates seed germination upon exposure to heavy metals is poorly understood. Here, we found (i) that seed priming with Mel considerably alleviated Cr stress during rice (Oryza sativa) seed germination and (ii) that germination performance was significantly improved in suppressor of the G2 allele of skp1 (OsSGT1) overexpression lines, while mutations of OsSGT1 and/or abscisic acid-insensitive 5 (OsABI5) noticeably abrogated such Mel-induced tolerance to Cr. Complementation assays suggested that the restored expression of OsSGT1 could not rescue the weak germination of sgt1-1abi5 under Cr stress, even upon Mel priming, but the expression of OsABI5 driven by the promoter of OsSGT1 significantly restored the Mel-ameliorated germination and the expression of ascorbate peroxidase 1 (OsAPX1) in sgt1-1abi5. Further analysis indicated that OsABI5 directly regulated the transcriptional expression of OsAPX1, whose encoding products promoted H2 O2 scavenging to maintain redox homeostasis, which is essential for germination. Collectively, this work demonstrates that OsSGT1 regulates OsABI5 to target OsAPX1, mediating the stimulatory effects of Mel on germination of Cr-stressed seeds, which provides a guide for the application of Mel in rice production.

Starch Properties of Roasting Rice from Naturally High-Resistant Starch Rice Varieties.

This study investigates the effects of moisture content control on the characteristics, properties, and in vitro starch digestion of roasted rice powder made from natural high-resistant starch (RS) rice varieties. The results demonstrate that adjusting the moisture content before roasting significantly affects the RS content of the roasted rice powder. Among various moisture levels tested, the addition of 15% water (rice-to-water ratio of 85:15) before roasting resulted in the highest RS content, reaching 22.61%. Several key parameters of the rice samples before and after optimal moisture control were analyzed, including thermal stability, chain length distribution, volatile flavor composition, and scanning electron microscopy. Additionally, in vitro digestion properties were measured. The findings revealed that the volatile flavor compounds in the high-RS roasted rice significantly increased compared to non-roasted rice. Moreover, the thermal stability of the rice samples improved, and the chain length distribution exhibited significant changes. The water absorption and expansion properties were significantly lower in the high-RS roasted rice. Furthermore, the in vitro starch digestion of the roasted flour made from high-RS rice showed a significantly lower digestion rate compared to common rice, indicating a lower starch hydrolysis index in high-RS rice with the sbe-rs genotype. Overall, the roasting process of natural high-RS rice modifies its characteristics, increases the RS content, enhances the flavor, and results in a lower starch digestion rate compared to common rice. This study provides valuable data for the food industry to promote the application of high-RS rice varieties with mutations in the SBEIIb gene, such as Youtangdao2 (YTD2).

Histone demethylase KDM2A suppresses EGF-TSPAN8 pathway to inhibit breast cancer cell migration and invasion in vitro.

Metastasis is a major cause of breast cancer mortality and the current study found histone demethylase, KDM2A, expression to be negatively correlated with breast cancer metastasis. KDM2A knockdown greatly promoted migration and invasion of breast cancer cells. The histone demethylase activity of KDM2A downregulated EGF transcription and suppressed the EGF-TSPAN8 pathway. Inhibition of breast cancer cell migration was also dependent on the histone demethylase activity of KDM2A. A novel mechanism of KDM2A-suppression of the EGF-TSPAN8 pathway which inhibited breast cancer cell migration and invasion is reported.

SNHG8 promotes cell proliferation, migration, and invasion of nasopharyngeal carcinoma cells as an oncogene through miR-588/HMGA2 axis.

Nasopharyngeal carcinoma (NC) poses a threat to the life of patients. Long non-coding RNA (LncRNA) is a novel kind of non-coding RNA, which plays a pivotal role through sponge microRNA (miRNA). Abnormal expression of small nucleolar RNA host gene 8 (SNHG8) is involved in various tumors; however, the role of SNHG8 in NC remains unknown. Quantitative real-time PCR (qRT-PCR) and Western blotting was employed to detect the expression levels of SNHG8, miR-588, and high mobility group A2 (HMGA2). Cell proliferation, migration, and invasion were analyzed by CCK-8 and transwell assays. miR-588 binding sites in SNHG8 were predicted by LncBase analysis. Luciferase reporter and RNA pull-down assay were used to confirm the interaction of SNHG8 and miR-588. SNHG8 was highly expressed in NC cells. The prognosis of the patients with NC in the high expression levels of SNHG8 was poorer than that in the low expression levels. The expression of SNHG8 was closely related to tumor size, TNM stage, and distal metastasis. Knockdown of SNHG8 inhibited cell proliferation, migration, and invasion of NC. SNHG8 targeted miR-588. Inhibition of miR-588 could partially reverse the knockdown of SNHG8 in NC cells, and miR-588 targeted HMGA2. In conclusion, SNHG8 promotes proliferation, migration, and invasion of NC cells through miR-588/HMGA2 in NC as an oncogene.

Melatonin Promotes SGT1-Involved Signals to Ameliorate Drought Stress Adaption in Rice.

Drought has become one of the environmental threats to agriculture and food security. Applications of melatonin (MT) serve as an effective way to alleviate drought stress, but the underlying mechanism remains poorly understood. Here, we found that foliar spray of 100-µM MT greatly mitigated the severe drought stress-induced damages in rice seedlings, including improved survival rates, enhanced antioxidant system, and adjusted osmotic balance. However, mutation of the suppressor of the G2 allele of skp1 (OsSGT1) and ABSCISIC ACID INSENSITIVE 5 (OsABI5) abolished the effects of MT. Furthermore, the upregulated expression of OsABI5 was detected in wild type (WT) under drought stress, irrespective of MT treatment, whereas OsABI5 was significantly downregulated in sgt1 and sgt1abi5 mutants. In contrast, no change of the OsSGT1 expression level was detected in abi5. Moreover, mutation of OsSGT1 and OsABI5 significantly suppressed the expression of genes associated with the antioxidant system. These results suggested that the functions of OsSGT1 in the MT-mediated alleviation of drought stress were associated with the ABI5-mediated signals. Collectively, we demonstrated that OsSGT1 was involved in the drought response of rice and that melatonin promoted SGT1-involved signals to ameliorate drought stress adaption.

The Association of Peripheral T Lymphocyte Subsets Disseminated Infection by Mycobacterium Tuberculosis in HIV-Negative Patients: A Retrospective Observational Study.

Background and Objective: This study was performed to investigate the association of peripheral T lymphocyte subsets with disseminated infection (DI) by Mycobacterium tuberculosis (MTB) in HIV-negative patients. Methods and Materials: The study included 587 HIV-negative tuberculosis (TB) patients. Results: In TB patients with DI, the proportion of CD4+ T cells decreased, the proportion of CD8+ T cells increased, and the ratio of CD4+/CD8+ T cells decreased. According to univariate analysis, smoking, alcohol consumption, rifampicin-resistance, retreatment, and high sputum bacterial load were linked to lower likelihood of developing MTB dissemination. Multivariate analysis indicated that after adjustment for alcohol use, smoking, retreatment, smear, culture, rifampicin-resistance, and CD4+/CD8+, the proportion of CD8+ T cells (but not CD4+ T cells) was independently and positively associated with the prevalence of DI in HIV-negative pulmonary TB (PTB) patients. Conclusions: Examining T lymphocyte subsets is of great value for evaluating the immune function of HIV-negative TB patients, and an increase in the CD8+ T cell proportion may be a critical clue regarding the cause of DI in such patients.

Expression profiling of TRIM gene family reveals potential diagnostic biomarkers for rifampicin-resistant tuberculosis.

The epidemic of pulmonary tuberculosis (TB), especially rifampin-resistant tuberculosis (RR-TB) presents a major challenge for TB control today. However, there is a lack of reliable and specific biomarkers for the early diagnosis of RR-TB. We utilized reverse transcription-quantitative polymerase chain reaction (RT-qPCR) to profile the transcript levels of 72 tripartite motif (TRIM) genes from a discovery cohort of 10 drug-sensitive tuberculosis (DS-TB) patients, 10 RR-TB patients, and 10 healthy controls (HCs). A total of 35 differentially expressed genes (DEGs) were screened out, all of which were down-regulated. The bio functions and pathways of these DEGs were enriched in protein ubiquitination, regulation of the viral process, Interferon signaling, and innate immune response, etc. A protein-protein interaction network (PPI) was constructed and analyzed using STRING and Cytoscape. Twelve TRIM genes were identified as hub genes, and seven (TRIM1, 9, 21, 32, 33, 56, 66) of them were verified by RT-qPCR in a validation cohort of 95 subjects. Moreover, we established the RR-TB decision tree models based on the 7 biomarkers. The receiver operating characteristic (ROC) analyses showed that the models exhibited the areas under the curve (AUC) values of 0.878 and 0.868 in discriminating RR-TB from HCs and DS-TB, respectively. Our study proposes potential biomarkers for RR-TB diagnosis, and also provides a new experimental basis to understand the pathogenesis of RR-TB.

Turbidity compensation method based on Mie scattering theory for water chemical oxygen demand determination by UV-Vis spectrometry.

In view of the problem that chemical oxygen demand (COD) measurement in water using UV-Vis spectrometry was easily affected by turbidity, this paper proposed an analytical method for determining the complex refractive index of particles in water based on Lambert-Beer's law and K-K (Kramers-Kronig) relationship. The obtained complex refractive index was used to establish the turbidity compensation model in the COD characteristic spectral region, and the COD concentration inversion were achieved by using the PLS algorithm. The results show that the turbidity compensation method based on Mie scattering theory can improve the accuracy of COD measurement by UV-Vis spectroscopy. Compared with before turbidity compensation, R2 (determination coefficient) between true values and predicted values of COD increased from 0.2274 to 0.9629, and RMSE (root mean square error) of predicted values decreased from 21.73 to 3.12 mg L-1. Compared with 350 nm PC, derivative method, and improved MSC method, the turbidity compensation method for COD measurement based on Mie scattering theory is simple, fast, and highly accurate. And the calculated spectrum can represent the scattering characteristics of the measured spectrum. The average relative error between the fitted spectrum and the original normalized spectrum in the 55 mixed solutions was 0.52%, and the maximum relative error was 6.65%. This method can be useful for online COD measurement. Graphical abstract.

Breeding for three-line japonica hybrid rice combinations with high resistant starch content using molecular marker-assisted selection.

Resistant starch (RS) is beneficial for human health, and especially for diabetics. Considering the high cost and low productivity of the Jiangtangdao 1 rice variety with high RS content, breeding high RS rice varieties exhibiting high productivity is essential. A molecular marker-assisted selection strategy was applied to increase RS content in a three-line hybrid rice variety. The functional rice variety Jiangtangdao 1, which contains sbe3-rs (on chr2) that controls the RS content, was used as the high RS content donor parent. Subsequently, male sterile maintainer and restorer lines containing homozygous sbe3-rs were bred using molecular marker-assisted selection combined with traditional breeding methods. The male sterile line was crossed with the restorer lines to identify the optimal hybrid combination with a high RS content. We obtained four combinations for which the yields were >50% higher than those of the control Jiangtangdao 1. In addition, there was no significant difference in the RS content between the combinations and Jiangtangdao 1. The hybrid rice plants with high RS content exhibited favorable agronomic traits and therefore have broad prospects for commercial application.

Concentration-Emission Matrix (CEM) Spectroscopy Combined with GA-SVM: An Analytical Method to Recognize Oil Species in Marine.

The establishment and development of a set of methods of oil accurate recognition in a different environment are of great significance to the effective management of oil spill pollution. In this work, the concentration-emission matrix (CEM) is formed by introducing the concentration dimension. The principal component analysis (PCA) is applied to extract the spectral feature. The classification methods, such as Probabilistic Neural Networks (PNNs) and Genic Algorithm optimization Support Vector Machine (SVM) parameters (GA-SVM), are used for oil identification and the recognition accuracies of the two classification methods are compared. The results show that the GA-SVM combined with PCA has the highest recognition accuracy for different oils. The proposed approach has great potential in rapid and accurate oil source identification.

On-line analysis of algae in water by discrete three-dimensional fluorescence spectroscopy.

In view of the problem of the on-line measurement of algae classification, a method of algae classification and concentration determination based on the discrete three-dimensional fluorescence spectra was studied in this work. The discrete three-dimensional fluorescence spectra of twelve common species of algae belonging to five categories were analyzed, the discrete three-dimensional standard spectra of five categories were built, and the recognition, classification and concentration prediction of algae categories were realized by the discrete three-dimensional fluorescence spectra coupled with non-negative weighted least squares linear regression analysis. The results show that similarities between discrete three-dimensional standard spectra of different categories were reduced and the accuracies of recognition, classification and concentration prediction of the algae categories were significantly improved. By comparing with that of the chlorophyll a fluorescence excitation spectra method, the recognition accuracy rate in pure samples by discrete three-dimensional fluorescence spectra is improved 1.38%, and the recovery rate and classification accuracy in pure diatom samples 34.1% and 46.8%, respectively; the recognition accuracy rate of mixed samples by discrete-three dimensional fluorescence spectra is enhanced by 26.1%, the recovery rate of mixed samples with Chlorophyta 37.8%, and the classification accuracy of mixed samples with diatoms 54.6%.

Study on Three-Dimensional Fluorescence Spectral Characteristics of Heterocyclic Pesticides in Different Environmental Conditions.

The impact analysis of different environments on the fluorescence emission spectrum of pesticides is critical in detecting the concentration of pesticides. In this paper, three kinds of pesticides, carbendazim, carbaryl and fuberidazole, were selected as the research objects. Under different environment, such as different pH values and the presence of different common anion or cation, three-dimensional fluorescence spectral emission (EEM) characteristic of pesticides were analyzed. The experimental results showed that the primary fluorescence peaks for three kinds of pesticides were at λex/λem=280/300, 310/340 and 280/335 nm (respectively); Carbendazim and fuberidazole had a secondary peak at 245/305 nm (PeakB) and 250/340 nm (PeakB). We can come to the conclusion that with the change of pH value, the characteristic of fluorescence emission of carbendazim and fuberidazole is similar. We can find that the fluorescence intensities of carbendazim and fuberidazole were enhanced with the declining of the solution acidity or alkalinity and the fluorescence intensity of carbaryl had not changed with the declining of the solution acidity, but it increased with the declining of the solution alkalinity; the fluorescence emission spectra of the three kinds of pesticides had good fluorescence characteristics with the scope of the pH varying from 6.16 to 7.4. Twelve common ions in water (CO2-3，SO2-4，NO-3，Cl-，HPO2-4，HCO-3，Mg2+，Zn2+，NH+4，Na+，Ca2+，K+) had no significant effect on fluorescence emission characteristics of carbendazim and fuberidazole. The fluorescence intensities were seriously influenced by Fe3+ and Cu2+. The results showed that the pesticides fluorescence intensities were decreased with the ion concentration increasing. It was necessary to consider the quenching effects on pesticides of Fe3+ and Cu2+for the analytic results. The obtained results provided the basic research for improving the accuracy of the heterocyclic pesticides measurement in water.

[Rapid Quantitative Detection of Bacterial in Water Based on Multi-Wavelength Scattering Spectra].

The structures of bacterial cells are analyzed in this paper. The scattering components of individual cell were divided into two parts including external structure and internal structure. The interpretation model of bacteria about scattering light is established. The model is used to analyze the scattering light of Escherichia coli in the region of 400~900 nm. The average size of external structure and the internal structure can be obtained, and the ratio of the two parts is also obtained. According to the relationship of the optical density of single cell and the overall measurement, the concentration of bacterial can be obtained quickly. The maximum difference in all the concentrations of the bacteria repeated measurements is 1.83%; compared with the plate culture method, the measurement results were in the same order of magnitude, with relative error of 3.43%. The scattering light of Escherichia coli and Klebsiella pneumoniae are analyzed in different growth stages, the curves of the concentration and the size of the two species bacteria over time are obtained. The results can provide a quick way for the study of bacterial growth and technical support for rapid detection of bacteria in the water.

In vivo HMRS and lipidomic profiling reveals comprehensive changes of hippocampal metabolism during aging in mice.

Aging is characterized by various cellular changes in the brain. Hippocampus is important for systemic aging and lifespan control. There is still a lack of comprehensive overview of metabolic changes in hippocampus during aging. In this study, we first created an accelerated brain aging mice model through the chronic administration of d-galactose. We then performed a multiplatform metabolomic profiling of mice hippocampus using the combination of in vivo 9.4 T HMRS and in vitro LC-MS/MS based lipidomics. We found N-acetylaspartic acid (NAA), gama-aminobutyric acid (GABA), glutamate/glutamine, taurine, choline, sphingolipids (SMs), phosphatidylethanolamines (PEs), phosphatidylinositols (PIs), phosphatidylglycerols (PGs) and phosphatidylserines (PSs), all of them decreasing with the aging process in mice hippocampus. The changes of sphingolipids and phospholipids were not limited to one single class or molecular species. In contrast, we found the significant accumulation of lactate, myoinositol and phosphatidylcholines (PCs) along with aging in hippocampus. SM (d18:1/20:2), PE (36:2), PG (34:1), PI (36:4), PS (18:0/20:4) and PC (36:0) have the most significant changes along with aging. Network analysis revealed the striking loss of biochemical connectivity and interactions between hippocampal metabolites with aging. The correlation pattern between metabolites in hippocampus could function as biomarkers for aging or diagnosis of aging-related diseases.

Efficient generation of marker-free transgenic rice plants using an improved transposon-mediated transgene reintegration strategy.

Marker-free transgenic plants can be developed through transposon-mediated transgene reintegration, which allows intact transgene insertion with defined boundaries and requires only a few primary transformants. In this study, we improved the selection strategy and validated that the maize (Zea mays) Activator/Dissociation (Ds) transposable element can be routinely used to generate marker-free transgenic plants. A Ds-based gene of interest was linked to green fluorescent protein in transfer DNA (T-DNA), and a green fluorescent protein-aided counterselection against T-DNA was used together with polymerase chain reaction (PCR)-based positive selection for the gene of interest to screen marker-free progeny. To test the efficacy of this strategy, we cloned the Bacillus thuringiensis (Bt) δ-endotoxin gene into the Ds elements and transformed transposon vectors into rice (Oryza sativa) cultivars via Agrobacterium tumefaciens. PCR assays of the transposon empty donor site exhibited transposition in somatic cells in 60.5% to 100% of the rice transformants. Marker-free (T-DNA-free) transgenic rice plants derived from unlinked germinal transposition were obtained from the T1 generation of 26.1% of the primary transformants. Individual marker-free transgenic rice lines were subjected to thermal asymmetric interlaced-PCR to determine Ds(Bt) reintegration positions, reverse transcription-PCR and enzyme-linked immunosorbent assay to detect Bt expression levels, and bioassays to confirm resistance against the striped stem borer Chilo suppressalis. Overall, we efficiently generated marker-free transgenic plants with optimized transgene insertion and expression. The transposon-mediated marker-free platform established in this study can be used in rice and possibly in other important crops.

Quantifying PAHs in water by three-way fluorescence spectra and second-order calibration methods.

It is still difficult to determine the concentrations of polycyclic aromatic hydrocarbons accurately in natural water by fluorescence technique because of their low solubility, different fluorescent intensity, and the complex interferents from water environments. In this work, three-way fluorescence spectra combined with three methods including three-way parallel factor analysis, multi-way partial least square with residual bilinearization and unfolded partial least square with residual bilinearization were used to predict the concentrations of polycyclic aromatic hydrocarbons at the µg L-1 level in reservoir and river water, respectively. The prediction abilities of these methods on different analytes were evaluated by validation sets. The results demonstrate that unfolded partial least square with residual bilinearization yields the optimal results with relative error less than or equal to 6% for phenanthrene, pyrene, anthracene and fluorene, and 35% for acenaphthene and fluoranthene in different water backgrounds.

A single amino acid mutation of OsSBEIIb contributes to resistant starch accumulation in rice.

Foods rich in resistant starch can help prevent various diseases, including diabetes, colon cancers, diarrhea, and chronic renal and hepatic diseases. Variations in starch biosynthesis enzymes could contribute to the high content of resistant starch in some cultivars of rice (Oryza sativa L.). Our previously published work indicated that the sbe3-rs gene in the rice mutant line, 'Jiangtangdao1' was a putative allele of the rice starch branching enzyme gene SBEIIb (previously known as SBE3); sbe3-rs might control the biosynthesis of the high resistant starch content in the rice line. Biomolecular analysis showed that the activity of SBEs was significantly lower in soluble extracts of immature seeds harvested from 'Jiangtangdao1' 15 days after flowering than in the extracts of the wild-type rice line 'Huaqingdao'. We performed gene complementation assays by introducing the wild-type OsSBEIIb into the sbe3-rs mutant 'Jiangtangdao1'. The genetically complemented lines demonstrated restored seed-related traits. The structures of endosperm amylopectin and the morphological and physicochemical properties of the starch granules in the transformants recovered to wild-type levels. This study provides evidence that sbe3-rs is a novel allele of OsSBEIIb, responsible for biosynthesis of high resistant starch in 'Jiangtangdao1'.

[Laser Induced Time-Resolved Fluorescence Spectroscopy Characteristics of Fluoranthene in Ethanol with Eanosecond Laser of 355 nm].

Polycyclic Aromatic Hydrocarbons (PAHs) have been widely investigated in environmental field, for most of them are mutagenic (carcinogenic, teratogenic, mutagenic). The influence of delay time and gate width on the time-resolved fluorescence spectroscopy of fluoranthene in ethanol was studied in this paper. Furthermore, laser induced time-resolved fluorescence spectroscopy of fluoranthene with different concentration were also researched. According to the results, fluorescence kinetics decay curves and fluorescence lifetime of fluoranthene matched. The research results showed that there was closely relationship between the fluorescence spectrum of fluoranthene and the delay time and gate width of detector. When the delay time was fixed, the fluorescence intensity of fluoranthene grew increased as the gate width increased. When the gate width was fixed, the fluorescence intensity of fluoranthene increased first and then decreased with the delay time increases. The process of the attenuation of fluorescence intensity of fluoranthene with time delay conformed to the exponential decay process. The stepwise dilution of fluoranthene ethanol solution was also studied. With increasing dilution, the fitting of fluoranthene fluorescence lifetime increased. The results of this paper can provide a technical basis for the detection of PAHs in the environment, due to the different characteristics of the fluorescent substance having fluorescence lifetime.