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Petroleum hydrocarbons are hazardous to ecosystems and human health, commonly containing n-alkanes and polycyclic aromatic hydrocarbons. Previous researches have studied alkane degraders and degrading genes under aerobic or anaerobic conditions, but seldom discussed them in the intermittent saturation zone which is a connective area between the vadose zone and the groundwater aquifer with periodic alteration of oxygen and moisture. The present study investigated the difference in alkane degradation efficiency, bacterial community, and alkane degrading gene diversity in aerobic, anaerobic, and aerobic-anaerobic fluctuated treatments. All biotic treatments achieved over 90% of n-alkane removal after 120 days of incubation. The removal efficiencies of n-alkanes with a carbon chain length from 16 to 25 were much higher in anaerobic scenarios than those in aerobic scenarios, explained by different dominant microbes between aerobic and anaerobic conditions. The highest removal efficiency was found in fluctuation treatments, indicating an accelerated n-alkane biodegradation under aerobic-anaerobic alternation. In addition, the copy numbers of the 16S rRNA gene and two alkB genes (alkB-P and alkB-R) declined dramatically when switched from aerobic to anaerobic scenarios and oppositely from anaerobic to aerobic conditions. This suggested that water level fluctuation could notably change the presence of aerobic alkane degrading genes. Our results suggested that alkane degradation efficiency, soil microbial community, and alkane-degrading genes were all driven by water level fluctuation in the intermittent saturation zone, helping better understand the effects of seasonal water table fluctuation on the biodegradation of petroleum hydrocarbons in the subsurface environment. [ABSTRACT FROM AUTHOR]

Underwater wireless sensor network (UWSN) is one of the effective methods to acquire ocean observation data, and research on underwater routing technology has become a hot spot. However, the lifetime of UWSN is an important factor affecting the overall performance of routing protocols. Due to the uncertain underwater environment and poor link quality, it will affect data integrity and network survival ability. Cooperative communication is an excellent technique for solving such problems. In this communication, the source node forwards data through a cooperative path to improve network throughput, while the destination node receives data packets that do not contain obvious errors. Therefore, this paper provides a cooperative communication method to solve the packet loss problem and lifetime of UWSN. The underwater-layered routing network structure is adopted to divide the network nodes into clusters for energy balance. Compared with the traditional layered protocol, the cooperative communication can better guarantee the link quality of the underwater channel. The k-means algorithm is also used to cluster nodes, and conditional probability can select cluster heads. During data transmission, relay nodes will amplify the signal and backup the data packets to avoid dropping packets. The proposed protocol is simulated and compared with non-cooperative protocols (LDBR and MLCEE), the results show that the proposed protocol outperformed the other protocols in terms of network lifetime, throughput, energy consumption and end-to-end delay. [ABSTRACT FROM AUTHOR]

Microorganisms are an important part of atmospheric particulate matter and are closely related to human health. In this paper, the variations in the characteristics of the chemical components and bacterial communities in PM10 and PM2.5 grouped according to season, pollution degree, particle size, and winter heating stage were studied. The influence of environmental factors on community structure was also analyzed. The results showed that seasonal variations were significant. NO3− contributed the most to the formation of particulate matter in spring and winter, while SO42− contributed the most in summer and autumn. The community structures in summer and autumn were similar, while the community structure in spring was significantly different. The dominant phyla were similar among seasons, but their proportions were different. The dominant genera were no-rank_c_Cyanobacteria, Acidovorax, Escherichia-Shigella and Sphingomonas in spring; Massilia, Bacillus, Acinetobacter, Rhodococcus, and Brevibacillus in summer and autumn; and Rhodococcus in winter. The atmospheric microorganisms in Beijing mainly came from soil, water, and plants. The few pathogens detected were mainly affected by the microbial source on the sampling day, regardless of pollution level. RDA (redundancy analysis) showed that the bacterial community was positively correlated with the concentration of particulate matter and that the wind speed in spring was positively correlated with NO3− levels, NH4+ levels, temperature, and relative humidity in summer and autumn, but there was no clear consistency among winter samples. This study comprehensively analyzed the variations in the characteristics of the airborne bacterial community in Beijing over one year and provided a reference for understanding the source, mechanism, and assessment of the health effects of different air qualities. [ABSTRACT FROM AUTHOR]

Objectives: Several studies have documented that dietary fiber was inversely associated with a variety of diseases, but the association of dietary fiber with the prognosis of older adults with hypertension is unknown. The aim was to assess the association of dietary fiber with all-cause and cardiovascular mortality in older adults with hypertension. Methods: This study enrolled 4906 participants (51.6% were female) aged 65 years or older with hypertension in the National Health and Nutrition Examination Survey (NHANES) 2003–2014 and ascertained mortality through December 31, 2015. Dietary fiber intake data were assessed by using a 24-h recall survey. Participants were grouped by dietary fiber intake quartiles: Q1(fiber < 10.20, g/day), Q2 (10.20 ≤ fiber < 14.45, g/day), Q3 (14.45 ≤ fiber < 19.85, g/day), and Q4 (19.85 ≤ fiber, g/day). Multivariate Cox proportional hazard models were used to evaluate the associations of dietary fiber intake with all-cause and cardiovascular mortality. Kaplan-Meier survival curves and restricted cubic spline models were applied to reveal the relationship between dietary fiber intake and mortality. Results: Over the median follow-up duration of 70 months (interquartile range: 38–100 months), 1369 participants were determined as all-cause mortality (27.9%) and 270 participants were identified as cardiovascular mortality (5.5%). In the fully adjusted model, the higher dietary fiber intake group was associated with relatively lower all-cause (Q4 vs Q1: 0.68 (0.58, 0.80); P for trend <0.001) and cardiovascular mortality (Q4 vs Q1: 0.64 (0.45, 0.92); P for trend =0.010). The non-linear relationship was not observed between dietary fiber intake and all-cause or cardiovascular mortality. Conclusions: Higher dietary fiber intake was significantly associated with decreased all-cause and cardiovascular mortality in older adults with hypertension. Increasing dietary fiber intake may improve the prognosis of older adults with hypertension. [ABSTRACT FROM AUTHOR]

Purpose: Amyloid β (Aβ) drives the accumulation of excess Phosphatase and Tensin Homolog Deleted on Chromosome 10 (PTEN) at synapses, inducing synaptic depression and perturbing memory. This recruitment of PTEN to synapses in response to Aβ drives its interaction with PSD95/Disc large/Zonula occludens-1 (PDZ) proteins and, indeed, we previously showed that an oligo lipopeptide (PTEN-PDZ) capable of blocking such PTEN:PDZ interactions rescues the synaptic and cognitive deficits in a mouse model of Alzheimer's disease. Hence, the PTEN:PDZ interaction appears to be crucial for Aβ-induced synaptic and cognitive impairment. Here we have evaluated the feasibility of using PTEN-PDZ lipopeptides based on the human/mouse PTEN C-terminal sequence, testing their stability in biological fluids, their cytotoxicity, their ability to self-assemble and their in vitro blood-brain barrier (BBB) permeability. Myristoyl or Lauryl tails were added to the peptides to enhance their cell permeability. Methods: Lipopeptides self assembly was assessed using electron microscopy and the thioflavin T assay. Stability studies in mouse plasma (50%), intestinal washing, brain and liver homogenates as well as permeability studies across an all human 2D blood-brain barrier model prepared with human cerebral endothelial cells (hCMEC/D3) and human astrocytes (SC-1800) were undertaken. Results: The mouse lauryl peptide displayed enhanced overall stability in plasma, ensuring a longer half-life in circulation that meant there were larger amounts available for transport across the BBB (Papp0-4h: 6.28 ± 1.85 × 10−6 cm s−1). Conclusion: This increased availability, coupled to adequate BBB permeability, makes this peptide a good candidate for therapeutic parenteral (intravenous, intramuscular) administration and nose-to-brain delivery. Graphical Abstract [ABSTRACT FROM AUTHOR]

Background: The association between uric acid (UA) and coronary artery disease (CAD) was controversial. It was still unclear how the UA level changes with age and gender. Aims: To confirm the relationship between the change of UA with age and gender and CAD, especially in elderly people. Methods: 8285 individuals were investigated. The changes of UA and hyperuricemia in female and male with age were analyzed. The associations of UA, and hyperuricemia with CAD in different age and sex were assessed. Results: Individuals were stratified into four groups according to their age: ≤ 39 years; 40–59 years; 60–79 years, and ≥ 80 years. The level of UA and the proportion of hyperuricemia increased significantly with age in female (P < 0.001), but showed a downward trend in male (P < 0.001). After adjusting for confounding factors, hyperuricemia remained an independent risk factor for the incident of CAD in all women (P = 0.029). In ≥ 80 year groups of female, UA and hyperuricemia became independent risk factors for the incident of CAD in the univariate and multivariate logistic regression analyses (all P ≤ 0.001). Discussion: The level of UA showed significantly different changes with age in different gender. The relationship between UA and CAD showed differences in different age and sex. Conclusions: There were significant correlations between UA, hyperuricemia, and CAD only in female, particularly in the ≥ 80 year elderly women, but not in men. [ABSTRACT FROM AUTHOR]

Fish intestines and livers are usually considered as delicious and nutritious food in China. Acidic polysaccharides are important nutrients in these food of animal origin, but there is currently little information regarding their quantitative distributions. The present study demonstrated a method to quantify acidic polysaccharides simultaneously by analyzing their disaccharides produced from the acid hydrolysis using high-performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry. The recoveries for these acidic polysaccharides were all 97%-115% with relative standard deviation of 3.0%-9.0%. All of the acidic polysaccharides had good linearities. Then this method was applied to determine the composition of acidic polysaccharides in 5 edible fish livers and intestines. Besides well-known glycosaminoglycans (GAGs) including hyaluronic acid (HA), Chondroitin sulfate (CS), dermatan sulfate (DS) and heparin (HP), 4 novel acidic polysaccharides including 2 GAGs and 2 non-GAGs comprised of hexose-hexuronic acid repeating units were also found. CS and HP were the major acidic polysaccharides components in fish intestines and livers, respectively. The absolute amounts of acidic polysaccharides differed greatly in these fish tissues, but their proportions showed similarity in the same type of tissues. The present study demonstrated an effective method for acidic polysaccharides quantification, and revealed acidic polysaccharides compositions of edible fish livers and intestines. [ABSTRACT FROM AUTHOR]

Potential threats exist where groundwater is polluted by high concentrations of oil compounds (980.20 mg L the highest TPHs). An abandoned petrochemical plant in Lanzhou City, where long-term petrochemical products leakage contaminated the groundwater, was used as a field site in this study. To determine the extent of pollution and find an effective solution, chemical techniques combined with molecular biological techniques were used to survey the migration and decomposition of pollutants. Moreover, Illumina Sequencing was employed to reveal the microbial changes of different sites. Light-chain alkanes (mostly C6-C9), most benzene compounds, and some polycyclic aromatic hydrocarbons (naphthalene, 2-methylnaphthalene) mainly polluted the source. C29 to C36 and chlorobenzenes (hexachlorocyclohexane) polluted the secondary polluted sites. Moreover, chloralkane (trichloroethane and dichloroethane), benzene derivatives (trimethylbenzene and butylbenzene), and PAHs (fluorene and phenanthrene) were present in the other longtime-contaminated water. The bacterial genera are closely related with the chemical matters, and different groups of microorganisms gather in the sample sites that are polluted with different kinds of oil. The biodiversity and abundance of observed species change with pollution conditions. The dominant phyla (81%) of the bacterial community structure are Proteobacteria (62.2% of the total microbes), Bacteroidetes (8.85%), Actinobacteria (6.70%), and Choloroflexi (3.03%). Pseudomonadaceae is significant in the oil-polluted source and Comamonadaceae is significant in the secondary polluted (migrated oil) sample; these two genera are natural decomposers of refractory matters. Amycolatopsis, Rhodocyclaceae, Sulfurimonas, and Sulfuricurvum are the dominant genera in the long-migrated oil-polluted samples. Bioavailability of the oil-contaminated place differs with levels of pollution and cleaning the worse-polluted sites by microbes is more difficult. [ABSTRACT FROM AUTHOR]

The Siberian tiger, Panthera tigris altaica, is an endangered species, and much more work is needed to protect this species, which is still vulnerable to extinction. Conservation efforts may be supported by the genetic assessment of wild populations, for which highly specific microsatellite markers are required. However, only a limited amount of genetic sequence data is available for this species. To identify the genes involved in the lung transcriptome and to develop additional simple sequence repeat (SSR) markers for the Siberian tiger, we used high-throughput RNA-Seq to characterize the Siberian tiger transcriptome in lung tissue (designated 'PTA-lung') and a pooled tissue sample (designated 'PTA'). Approximately 47.5 % (33,187/69,836) of the lung transcriptome was annotated in four public databases (Nr, Swiss-Prot, KEGG, and COG). The annotated genes formed a potential pool for gene identification in the tiger. An analysis of the genes differentially expressed in the PTA lung, and PTA samples revealed that the tiger may have suffered a series of diseases before death. In total, 1062 non-redundant SSRs were identified in the Siberian tiger transcriptome. Forty-three primer pairs were randomly selected for amplification reactions, and 26 of the 43 pairs were also used to evaluate the levels of genetic polymorphism. Fourteen primer pairs (32.56 %) amplified products that were polymorphic in size in P. tigris altaica. In conclusion, the transcriptome sequences will provide a valuable genomic resource for genetic research, and these new SSR markers comprise a reasonable number of loci for the genetic analysis of wild and captive populations of P. tigris altaica. [ABSTRACT FROM AUTHOR]

Triptolide is a bioactive component of Chinese herbal plant Tripterygium wilfordii Hook F that has recently been noted to attenuate hepatic and cerebral ischemia/reperfusion (I/R) injuries in rodents. To investigate whether triptolide could protect against myocardial I/R injuries, triptolide (25, 50 or 100 μg/kg) was administrated in Wistar rats that underwent left anterior descending coronary artery ligation in this study. Our data showed that triptolide pretreatment could attenuate myocardial infarction, increase the fractional shortening and left ventricular systolic pressure and decrease the left ventricular end-diastolic pressure in ischemic rats. Also, triptolide was noted to inhibit the activities of lactate dehydrogenase and creatine kinase in I/R rats. Moreover, triptolide administration suppressed macrophage infiltration, inhibited the overproduction of tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and malondialdehyde (MDA) in reperfused myocardium tissues and upregulated the activities of antioxidative superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GPx). In addition, nuclear accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and the activity of its downstream target Heme oxygenase-1 (HO-1) in ischemic myocardium tissues were enhanced by triptolide pretreatment. In addition, the HO-1 inhibitor, zinc protoporphyrin-IX, abrograted the cardiac protection mediated by triptolide. Our study reveals a novel cardioprotective effect of triptolide in rats with I/R injuries, wherein the activation of Nrf2/HO-1 signaling was involved. [ABSTRACT FROM AUTHOR]

The connection between microbial community structure and spatial variation and pollution in river waters has been widely investigated. However, water and sediments together have rarely been explored. In this study, Illumina high-throughput sequencing was performed to analyze microbes in 24 water and sediment samples from natural to anthropogenic sources and from headstream to downstream areas. These data were used to assess variability in microbial community structure and diversity along in the Fenghe River, China. The relationship between bacterial diversity and environmental parameters was statistically analyzed. An average of 1682 operational taxonomic units was obtained. Microbial diversity increased from the headstream to downstream and tended to be greater in sediment compared with water. The water samples near the headstream endured relatively low Shannon and Chao1 indices. These diversity indices and the number of observed species in the water and sediment samples increase downstream. The parameters also differ in the two river tributaries. Community structures shift based on the extent of nitrogen pollution variation in the sediment and water samples. The four most dominant genera in the water community were Escherichia, Acinetobacter, Comamonadaceae, and Pseudomonas. In the sediments, the most dominant genera were Stramenopiles, Flavobacterium, Pseudomonas, and Comamonadaceae. The number of ammonia-oxidizing archaea in the headstream water slightly differed from that in the sediment but varied considerably in the downstream sediments. Statistical analysis showed that community variation is correlated with changes in ammonia nitrogen, total nitrogen, and nitrate nitrogen. This study identified different microbial community structures in river water and sediments. Overall this study emphasized the need to elucidate spatial variations in bacterial diversity in water and sediments associated with physicochemical gradients and to show the effects of such variation on waterborne microbial community structures. [ABSTRACT FROM AUTHOR]

Growing evidences show that matrix metalloproteinase 1 (MMP1) plays important roles in tumorigenesis and cancer metastasis. MMP1 −1607 1G>2G is a single nucleotide polymorphism in the promoter region of MMP1 and affects MMP1 production. Analysis of previous studies on the association of −1607 1G>2G polymorphism with different cancer types remained to be illustrated. To further assess the effect of −1607 1G>2G polymorphism on cancer risk, we performed this meta-analyses, up to September 8, 2014, of 10,640 cases and 10,915 controls from 42 published case-control designed studies. Statistical analyses were performed using STATA 11.0 software. Crude odds ratios (ORs) with 95 % confidence intervals (CIs) were used to assess the strength of associations. ORs with 95 % CIs for the polymorphism MMP1 −1607 1G>2G and cancer were estimated using fixed and random effects models when appropriate. Significantly increased risks were found in overall under the models of 2G vs.1G, 2G2G vs. 1G1G, 2G2G/1G2G vs. 1G1G, and 2G2G vs. 2G1G/1G1G. Significantly elevated risks were observed in colorectal adenoma under the models of 2G vs. 1G, 2G2G vs. 1G1G, 2G2G/1G2G vs. 1G1G, and 2G2G vs. 2G1G/1G1G and lung cancer and head and neck cancer under the models of 2G vs. 1G. We found that significantly elevated risks were observed in Asian population and hospital-based studies in most comparison models tested. Thus, this meta-analysis indicates that the polymorphism MMP1 −1607 1G>2G is significantly associated with a significantly increased risk of cancers and may provide evidence-based medical certificate to study the cancer susceptibility. [ABSTRACT FROM AUTHOR]

Confocal microscopy is a powerful and effective tool for in vivo elucidation of the molecular basis of biological molecules. Chemical labeling of non-ultraviolet or non-fluorescent carbohydrate with fluorescent tag is an essential step that makes intra-cellular microscopic inspection possible. However, current labeling methods have proved unsuitable for functional pectin-derived oligogalacturonic acid due to the low fluorescence intensity and/or the formation of lactone byproducts. Here, fluorescein-5-thiosemicarbazide (FTSC) was employed for fluorescent labeling of pectin-derived oligogalacturonic acid under mild and neutral reaction conditions to avoid the generation of lactone byproducts. ESI-MS and LC-MS data displayed that pectin-derived pentagalacturonic acid, GalA, could be quantitatively labeled with FTSC to afford thiosemicarbazones, without any lactone byproducts yielded. Moreover, GalA-FTSC thiosemicarbazone showed good stability and desirable fluorescence characteristics and exhibited rather low levels of cytotoxicity against sensitive rat thymus cells. Additionally, we have achieved successful fluorescent imaging of GalA-FTSC thiosemicarbazones transported in living SW-620 and HepG2 cells. The assay illustrates methodological significance in structure-activity elucidation study of functional carbohydrates especially acid oligo-/polysaccharides. [ABSTRACT FROM AUTHOR]

Mucin-type O-linked glycoproteins are known for regulating many aspects of cell activity but remains a challenge to detect under physiological conditions which is due to the diversity of O-glycosylation and the lack of universal method. Here a direct labeling strategy for in situ visualizing of mucin-type O-linked glycoproteins on living cells has been developed. The strategy utilizes the combination of metabolic engineering and chemical probing technologies. Treating cells with an unnatural sugar, 2-keto AcGalNAc analogue (2-keto isostere of GalNAc) to generate keto groups upon cells, followed by chemoselective ligation of keto groups on cells with a fluorescent tag, fluorescein-5-thiosemicarbazide (FTSC), provides a promising platform to probing mucin-type O-glycosylation on living cells. The FTSC conjugates illustrated very similar fluorescent spectra as FITC, a fluorescent tag widely used in proteomics, indicating good compatibility with commonly used fluorescent equipments. The established method eliminated the need of an additional fluorescent amplification step. Cells after being treated with the method maintained a rather high level of viability of 84.3 %. Finally, the assay has been successfully applied to image the expression of mucin-type O-linked glycoproteins within CHO and HeLa cells. [ABSTRACT FROM AUTHOR]

Functional receptive fields of neurons in sensory cortices undergo progressive refinement during development. Such refinement may be attributed to the pruning of non-optimal excitatory inputs, reshaping of the excitatory tuning profile through modifying the strengths of individual inputs, or strengthening of cortical inhibition. These models have not been directly tested because of the technical difficulties in assaying the spatiotemporal patterns of functional synaptic inputs during development. Here we apply in vivo whole-cell voltage-clamp recordings to the recipient layer 4 neurons in the rat primary auditory cortex (A1) to determine the developmental changes in the frequency–intensity tonal receptive fields (TRFs) of their excitatory and inhibitory inputs. Surprisingly, we observe co-tuned excitation and inhibition immediately after the onset of hearing, suggesting that a tripartite thalamocortical circuit with relatively strong feedforward inhibition is formed independently of auditory experience. The frequency ranges of tone-driven excitatory and inhibitory inputs first expand within a few days of the onset of hearing and then persist into adulthood. The latter phase is accompanied by a sharpening of the excitatory but not inhibitory frequency tuning profile, which results in relatively broader inhibitory tuning in adult A1 neurons. Thus the development of cortical synaptic TRFs after the onset of hearing is marked by a slight breakdown of previously formed excitation–inhibition balance. Our results suggest that functional refinement of cortical TRFs does not require a selective pruning of inputs, but may depend more on a fine adjustment of excitatory input strengths. [ABSTRACT FROM AUTHOR]

Synaptic inputs underlying spike receptive fields are important for understanding mechanisms of neuronal processing. Using whole-cell voltage-clamp recordings from neurons in mouse primary visual cortex, we examined the spatial patterns of their excitatory and inhibitory synaptic inputs evoked by On and Off stimuli. Neurons with either segregated or overlapped On/Off spike subfields had substantial overlaps between all the four synaptic subfields. The segregated receptive-field structures were generated by the integration of excitation and inhibition with a stereotypic 'overlap-but-mismatched' pattern: the peaks of excitatory On/Off subfields were separated and flanked colocalized peaks of inhibitory On/Off subfields. The small mismatch of excitation/inhibition led to an asymmetric inhibitory shaping of On/Off spatial tunings, resulting in a great enhancement of their distinctiveness. Thus, slightly separated On/Off excitation, together with intervening inhibition, can create simple-cell receptive-field structure and the dichotomy of receptive-field structures may arise from a fine-tuning of the spatial arrangement of synaptic inputs. [ABSTRACT FROM AUTHOR]

The evolution of activated sludge settleability and its relationship to membrane fouling in a submerged membrane bioreactor were studied at a lab-scale equipment fed with synthetic wastewater. It was found that sludge volume index (SVI) gradually increased and the sludge settleability was reduced, which was caused by the propagation of filamentous bacteria. With increasing SVI, the average increasing rate of trans-membrane pressure increased, the stable filtration period was shortened, and the two stages (smooth stage and accelerating stage) of the trans-membrane pressure were more obvious. At the same time, the increasing rate of trans-membrane pressure at the smooth stage decreased and the rate at the accelerating stage increased with SVI, respectively. The observation by using scanning electronic microscopes showed the cake layer with loose structure and large thickness formed on the membrane surface due to the appearance of filamentous bacteria and high SVI in sludge. Influence of the sludge settleability on the trans-membrane pressure was related to the structure and thickness of the cake layer on the membrane. [ABSTRACT FROM AUTHOR]

A dual-channel ratiometric method is presented for improved colorimetric and fluorometric visualization of the fungicide cymoxanil (CYM). It is based on the use of a mixture of dually emitting carbon dots (CDs) and citrate-stabilized silver nanoparticles (AgNPs). The CDs, under photoexcitation at 350 nm, display dual (blue and green) fluorescence, with peaks at 435 and 520 nm. In mixed aqueous suspension of CDs and AgNPs, the intensity of blue fluorescence of CDs is reduced due to internal filter effect (IFE). This is due to the spectral overlap between the emission of CDs and the absorption of yellow AgNPs. After the addition of CYM to the mixture, CYM triggers the aggregation of AgNPs due to electrostatic attraction and hydrogen bonding interactions. The aggregated AgNPs have an orange color with an absorption whose maximum is shifted to around 510 nm. Hence, it overlaps the green emission of CDs. This causes an IFE on the green fluorescence, while the blue fluorescence is recovered. The colorimetric is performed by ratioing the absorbances at 515 and 390 nm. The ratiometric fluorometric assay is based on ratioing the emissions at 435 and 520 nm. The assay has a wide detection range (0.01–0.55 μΜ) and a low limit of detection (2 nM at S/N = 3). The assay was applied to the determination of CYM in spiked real samples (natural river water, soil and plant epidermis). Recoveries ranged between 97 and 105%. The method enables assays to perform on-site and visual detection by observing fluorescence color shades in either aqueous solutions and on wetted filter paper strips. [ABSTRACT FROM AUTHOR]