A Novel Soft Clustering Method for Detection of Exudates

One of the earliest indications of diabetes consequence is Diabetic Retinopathy(DR),the main contributor to blindness worldwide.Recent studies have proposed that Exudates(EXs)are the hallmark of DR severity.The present study aims to accurately and automatically detect EXs that are difficult to detect in retinal images in the early stages.An improved Fusion of Histogram-Based Fuzzy C-Means Clustering(FHBFCM)by a New Weight Assignment Scheme(NWAS)and a set of four selected features from stages of pre-processing to evolve the detection method is proposed.The features of DR train the optimal parameter of FHBFCM for detecting EXs diseases through a stepwise enhancement method through the coarse segmentation stage.The histogram-based is applied to find the color intensity in each pixel and performed to accomplish Red,Green,and Blue(RGB)color information.This RGB color information is used as the initial cluster centers for creating the appropriate region and generating the homogeneous regions by Fuzzy C-Means(FCM).Afterward,the best expression of NWAS is used for the delicate detection stage.According to the experiment results,the proposed method successfully detects EXs on the retinal image datasets of DiaretDB0(Standard Diabetic Retinopathy Database Calibration level 0),DiaretDB1(Standard Diabetic Retinopathy Database Calibration level 1),and STARE(Structured Analysis of the Retina)with accuracy values of 96.12%,97.20%,and 93.22%,respectively.As a result,this study proposes a new approach for the early detection of EXs with competitive accuracy and the ability to outperform existing methods by improving the detection quality and perhaps significantly reducing the segmentation of false positives.

Effects of maize root exudates and organic acids on the desorption of phenanthrene from soils

The effects of maize root exudates and low-molecular-weight-organic anions （LMWOAs） on the desorption of phenanthrene from eight artificially contaminated soils were evaluated. A significant negative correlation was observed between the amounts of phenanthrene desorbed and the soil organic carbon （SOC） contents （P 〈 0.01）, and the influences of soil pH and clay content on phenanthrene desorption were insignificant （P 〉 0.1）. Neither maize root exudates nor oxalate and citrate anions influenced desorption of phenanthrene with the addition of NaN3. A faster phenanthrene desorption occurred without the addition of NaN3 in the presence of maize root exudates than oxalate or citrate due to the enhanced degradation by root exudates. Without the addition of NAN3, oxalate or citrate at different concentrations could inhibit phenanthrene desorption to different extents and the inhibiting effect by citrate was more significant than by oxalate. This study leads to the conclusion that maize root exudates can not enhance the desorption under abiotic condition with the addition of NaN3 and can promote the desorption of phenanthrene in soils without the addition of NaN3.

Artificial root exudates and soil organic carbon mineralization in a degraded sandy grassland in northern China

Plant root exudates contain various organic and inorganic components that include glucose, citric and oxalic acid. These components affect rhizosphere microbial and microfaunal activities, but the mechanisms are not fully known. Studies concerned from degraded grassland ecosystems with low soil carbon（C） contents are rare, in spite of the global distribution of grasslands in need of restoration. All these have a high potential for carbon sequestration, with a reduced carbon content due to overutilization. An exudate component that rapidly decomposes will increase soil respiration and CO2 emission, while a component that reduces decomposition of native soil carbon can reduce CO2 emission and actually help sequestering carbon in soil. Therefore, to investigate root exudate effects on rhizosphere activity, citric acid, glucose and oxalic acid（0.6 g C/kg dry soil） were added to soils from three biotopes（grassland, fixed dune and mobile dune） located in Naiman, Horqin Sandy Land, Inner Mongolia, China） and subjected to a 24-day incubation experiment together with a control. The soils were also analyzed for general soil properties. The results show that total respiration without exudate addition was highest in grassland soil, intermediate in fixed dune and lowest in mobile dune soil. However, the proportion of native soil carbon mineralized was highest in mobile dune soil, reflecting the low C/N ratio found there. The exudate effects on CO2-C emissions and other variables differed somewhat between biotopes, but total respiration（including that from the added substrates） was significantly increased in all combinations compared with the control, except for oxalic acid addition to mobile dune soil, which reduced CO2-C emissions from native soil carbon. A small but statistically significant increase in pH by the exudate additions in grassland and fixed dune soil was observed, but there was a major decrease from acid additions to mobile dune soil. In contrast, electrical conductivity decreased in grassland and fixed dune soil and increased in mobile dune. Thus, discrete components of root exudates affected soil environmental conditions differently, and responses to root exudates in soils with low carbon contents can differ from those in normal soils. The results indicate a potential for, e.g., acid root exudates to decrease decomposition rate of soil organic matter in low carbon soils, which is of interest for both soil restoration and carbon sequestration.

The Extraction,Isolation and Identification of Exudates from the Roots of Flaveria bidentis

Large amounts ofFlaveria bidentis＇s root culturing solution were obtained by using DFT （deep flow technique） equipment and these solution which was vacuum concentrated （10, 20 mg mL-~） can have a certain inhibition on Triticum aestivum, Cucumis sativus, Raphanus sativus, Amaranthus retroflexus, Setaria viridis, Chenopodium album, Echinochloa crusgalli and Chloris virgata. This outcome suggested some active compounds in the root exudates ofFIaveria bidentis can inhibit the germination, seedling elongation and root length. The dichloromethane extract of root exudates was identificated by GC-MS, and 29 kinds of compounds, including esters, hydrocarbons, ketones, thiazole, amines, etc. were obtained and the phthalate n-octyl ester, phthalate 2-ethylhexyl ester were proved to be allelochemicals. The culturing solution of root exudates was separated through the resin column and silica gel column and a component inhibiting seedling height, root length and fresh weight of wheat was got. There were 6 kinds of organic compounds in this component including dioctyl phthalate, 1,2-phthalate, mono（2-ethylhexyl） ester by GC-MS.

Accelerated degradation of a variety of aromatic compounds by Spirodela polyrrhiza-bacterial associations and contribution of root exudates released from S. polyrrhiza

Removal experiments of phenol, aniline, 2,4-dichlorophenol, nonylphenol and bisphenol A （BPA） using Spirodela polyrrhiza- bacterial associations revealed that all compounds but BPA underwent accelerated removal. The mechanisms differed depending on the substrates. It was found that S. polyrrhiza has a great ability to release phenolic compound-rich root exudates, and the exudates seem to stimulate bacterial degradation of a variety of aromatic compounds.

Differential Responses of Phytophthora sojae to Seed Exudates of Host Soybean and Non-host Maize

In order to clarify the differential response of Phytophthora sojae to the seed exudates of host soybean and non-host maize and understand the relationship between seed exudates and host selectivity of Phytophthora sojae, non-host maize Suiyu 23 and susceptible host soybean Sloan seed exudates were collected to measure their influence on mycelial growth, formation and germination of oospores, chemotaxis, encystment and germination of zoospores of Phytophthora sojae. The results showed that nonhost maize seed exudates exhibited repellency to zoospores of Phytophthora sojae, it also could significantly inhibited Phytophthora sojae mycelial growth, formation of oospores compared with the control;compared with host soybean, non-host maize seed exudates could significantly inhibited Phytophthora sojae mycelial growth, formation and germination of oospores, germination of cysts, which indicated that the seed exudates was the critical factor to host selectivity of Phytophthora sojae and the maize seed exudates was closely related to its non-host resistance.

Exogenous Inoculation of Microorganisms Effect on Root Exudates and Rhizosphere Microorganism of Tobaccos

Studying the relationship between rhizosphere microorganisms and root exudates is of great significance for the interaction between rhizosphere microorganisms and plants, and the prevention and control of soil-borne diseases. This article analyzed the effects of different microorganisms on tobacco root exudates and rhizosphere microorganisms. It was found that the bacterial wilt pathogen can greatly increase acids and amines, while the probiotic B. amyloliquefaciens ZM9 can eliminate some acids and amines. The results of the study show that the root exudates of pathogenic bacteria may contain a variety of allelochemicals that cause soil-borne diseases.

A novel method for detection of hard exudates from fundus images based on SVM and improved FCM

Diabetic retinopathy(DR) is one of the most important causes of visual impairment. Automatic recognition of DR lesions, like hard exudates(EXs), in retinal images can contribute to the diagnosis and screening of the disease. To achieve this goal, an automatically detecting approach based on improved FCM(IFCM) as well as support vector machines(SVM) was established and studied. Firstly, color fundus images were segmented by IFCM, and candidate regions of EXs were obtained. Then, the SVM classifier is confirmed with the optimal subset of features and judgments of these candidate regions, as a result hard exudates are detected from fundus images. Our database was composed of 126 images with variable color, brightness, and quality. 70 of them were used to train the SVM and the remaining 56 to assess the performance of the method. Using a lesion based criterion, we achieved a mean sensitivity of 94.65% and a mean positive predictive value of 97.25%. With an image-based criterion, our approach reached a 100% mean sensitivity, 96.43% mean specificity and 98.21% mean accuracy. Furthermore, the average time cost in processing an image is 4.56 s. The results suggest that the proposed method can efficiently detect EXs from color fundus images and it could be a diagnostic aid for ophthalmologists in the screening for DR.

Com parison of Amino Acids in Root Exudates of Flue-cured Tobacco Varieties with Different Resistances against Black Shank

In order to explore the differences of amino acids in root exudates and plant tissues, we selected four flue-cured tobacco varieties [ Yunyan 87 （ Ⅰ）, K326 （Ⅱ）, NC102（Ⅲ）, Hongda （Ⅳ）] as the test materials and studied the components and mass fractions of amino acids in rhizosphere soil, non rhizosphere soil, roots and leaves via high performance capillary zone electrophoresis. Ten amino acids were detected out from four varieties, including histidine, lysine, tryptophan, phenylalanine, valine, threonine, proline, serine, alanine and glycine. The mass fractions of amino acids in leaves and roots were higher than those in rhizosphere soil and non rhizosphere soil. In rhizosphere soil and non-rhizosphere soil, the mass fractions of lysine, phenylalanine, threonine, proline and glycine in susceptible varieties （ Ⅲ, Ⅳ） were higher than those in resistant varieties （ Ⅰ, Ⅱ）. In rhizosphere soil, the total amino acids successively were Ⅳ 〉 Ⅲ 〉 Ⅰ 〉 Ⅱ, and in non rhi- zosphere soil were Ⅲ 〉 Ⅳ 〉 Ⅰ 〉 Ⅱ. The total amino acids in roots of variety Ⅳ was the highest, up to 6 359. 195 μg/g. In leaves, the total amino acids in varieties I and If were higher than those in varieties IfI and IV. The results indicated that amino acids could secrete to rhizosphere via root secretion, and the compositions and mass fractions of amino acids varied with flue-cured tobacco varieties, thus the secretion amount of susceptible varieties was higher than that of resistant varieties.

Segmentation and texture analysis with multimodel inference for the automatic detection of exudates in early diabetic retinopathy

Diabetic retinopathy (DR) is an eye disease caused by the increase of insulin in blood and may cause blindness if not treated at an early stage. Exudates are the primary sign of DR. Currently there is no fully automated method to detect exudates in the literature and it would be useful in large scale screening if fully automatic method is available. In this paper we developed a novel method to detect exudates that based on interactions between texture analysis and segmentation with mathematical morphological technique by using multimodel inference. The texture analysis involves three components: they are statistical texture analysis, high order spectra analysis, and fractal analysis. The performance of the proposed method is assessed by the sensitivity, specificity and accuracy using the public data DIARETDB1. Our results show that the sensitivity, specificity and accuracy are 95.7%, 97.6% and 98.7% (SE = 0.01), respectively. It is shown that the proposed method can be run automatically and also improve the accuracy of exudates detection significantly over most of the previous methods.

Automated Exudates Detection in Retinal Fundus Image Using Morphological Operator and Entropy Maximization Thresholding

Blindness which is considered as degrading disabling disease is the final stage that occurs when a certain threshold of visual acuity is overlapped. It happens with vision deficiencies that are pathologic states due to many ocular diseases. Among them, diabetic retinopathy is nowadays a chronic disease that attacks most of diabetic patients. Early detection through automatic screening programs reduces considerably expansion of the disease. Exudates are one of the earliest signs. This paper presents an automated method for exudates detection in digital retinal fundus image. The first step consists of image enhancement. It focuses on histogram expansion and median filter. The difference between filtered image and his inverse reduces noise and removes background while preserving features and patterns related to the exudates. The second step refers to blood vessel removal by using morphological operators. In the last step, we compute the result image with an algorithm based on Entropy Maximization Thresholding to obtain two segmented regions (optical disk and exudates) which were highlighted in the second step. Finally, according to size criteria, we eliminate the other regions obtain the regions of interest related to exudates. Evaluations were done with retinal fundus image DIARETDB1 database. DIARETDB1 gathers high-quality medical images which have been verified by experts. It consists of around 89 colour fundus images of which 84 contain at least mild non-proliferative signs of the diabetic retinopathy. This tool provides a unified framework for benchmarking the methods, but also points out clear deficiencies in the current practice in the method development. Comparing to other recent methods available in literature, we found that the proposed algorithm accomplished better result in terms of sensibility (94.27%) and specificity (97.63%).

Effects of Tobacco Pathogens and Their Antagonistic Bacteria on Tobacco Root Exudates

The research on relationship between rhizosphere microbes and root exudates has a great significance on discussion of interaction between rhizosphere microbes and plants, as well as control of soil-borne diseases and insect pest. GC-MS was used to analyze changes of tobacco root exudates under the antagonistic action of tobacco bacterial wilt and black shank. It turned out that when pathogens of tobacco bacterial wilt and black shank in tobacco root microorganisms increase, tobacco root exudates augmented rapidly among of which organic acids have the biggest growth, followed by amines. When the pathogens of tobacco bacterial wilt and black shank are inhibited by the active substance of antagonistic antibacterial, 20 - 23 kinds of root exudates are added;besides, the content of 7 substances was reduced to 0. Another inter-esting finding was that the fluctuations of phthalic acid, isophthalic acid and benzoic acid, which have caused continuous cropping obstacles, were very dis-tinct. The results of this study have provided novel clues for the exploration of continuous tobacco cropping obstacles and soil-borne diseases.

Identification of Diabetic Retinal Exudates in Digital Color Images Using Support Vector Machine

Support vector machine (SVM) has become an increasingly popular tool for machine learning tasks involving classification. In this paper, we present a simple and effective method of detect and classify hard exudates. Automatic detection of hard exudates from retinal images is worth-studying problem since hard exudates are associated with diabetic retinopathy and have been found to be one of the most prevalent earliest signs of retinopathy. The algorithm is based on Discrete Cosine Transform (DCT) analysis and SVM makes use of color information to perform the classification of retinal exudates. We prospectively assessed the algorithm performance using a database containing 1200 retinal images with variable color, brightness, and quality. Results of the proposed system can achieve a diagnostic accuracy with 97.0% sensitivity and 98.7% specificity for the identification of images containing any evidence of retinopathy.

Study on the antibiosis of exudate JK-91-b against rice sheath blight (SHB)

Antagonistic bacterial strain 91-b possessedstronger antagonistic ability against SHBinfection. The control effects of the bacterizationagainst SHB were 58.1% in greenhouse and 45.1%in paddy. The effect of antibiosis JK-91-b exudat-ed by strain 91-b was studied in the present re-search.Bacterial strain 91-b was inoculated into

Interspecific plant interaction via root exudates structures the disease suppressiveness of rhizosphere microbiomes

Terrestrial plants can affect the growth and health of adjacent plants via interspecific interaction.Here,we studied the mechanism by which plant root exudates affect the recruitment of the rhizosphere microbiome in adjacent plants—with implications for plant protection—using a tomato(Solanum lycopersicum)–potatoonion(Allium cepa var.agrogatum)intercropping system.First,we showed that the intercropping system results in a disease-suppressive rhizosphere microbiome that protects tomato plants against Verticillium wilt disease caused by the soilborne pathogen Verticillium dahliae.Second,16S rRNA gene sequencing revealed that intercropping with potatoonion altered the composition of the tomato rhizosphere microbiome by promoting the colonization of specific Bacillus sp.This taxon was isolated and shown to inhibit V.dahliae growth and induce systemic resistance in tomato plants.Third,a belowground segregation experiment found that root exudates mediated the interspecific interaction between potatoonion and tomato.Moreover,experiments using split-root tomato plants found that root exudates from potatoonion,especially taxifolin—a flavonoid compound—stimulate tomato plants to recruit plant-beneficial bacteria,such as Bacillus sp.Lastly,ultra-high-pressure liquid chromatography–mass spectrometry analysis found that taxifolin alters tomato root exudate chemistry;thus,this compound acts indirectly in modulating root colonization by Bacillus sp.Our results revealed that this intercropping system can improve tomato plant fitness by changing rhizosphere microbiome recruitment via the use of signaling chemicals released by root exudates of potatoonion.This study revealed a novel mechanism by which interspecific plant interaction modulates the establishment of a disease-suppressive microbiome,thus opening up new avenues of research for precision plant microbiome manipulations.

Root exudates increased arsenic mobility and altered microbial community in paddy soils

Root exudates are crucial for plants returning organic matter to soils,which is assumed to be a major source of carbon for the soil microbial community.This study investigated the influence of root exudates on the fate of arsenic(As)with a lab simulation experiment.Our findings suggested that root exudates had a dose effect on the soil physicochemical properties,As speciation transformation and the microbial community structure at different concentrations.The addition of root exudates increased the soil pH while decreased the soil redox potential(Eh).These changes in the soil pH and Eh increased As and ferrous(Fe(Ⅱ))concentrations in soil porewater.Results showed that 40 mg/L exudates addition significantly increased arsenite(As(Ⅲ))and arsenate(As(Ⅴ))by 541 and 10 times respectively within 30 days in soil porewater.The relative abundance of Fe(Ⅲ)-reducing bacteria Geobacter and Anaeromyxobacter increased with the addition of root exudates,which enhanced microbial Fe reduction.Together these results suggest that investigating how root exudates affect the mobility and transformation of As in paddy soils is helpful to systematically understand the biogeochemical cycle of As in soil-rice system,which is of great significance for reducing the health risk of soil As contamination.

RIN enhances plant disease resistance via root exudate-mediated assembly of diseasesuppressive rhizosphere microbiota

The RIPENING-INHIBITOR(RIN)transcriptional factor is a key regulator governing fruit ripening.While RIN also affects other physiological processes,its potential roles in triggering interactions with the rhizosphere microbiome and plant health are unknown.Here we show that RIN affects microbiome-mediated disease resistance via root exudation,leading to recruitment of microbiota that suppress the soil-borne,phytopathogenic Ralstonia solanacearum bacterium.Compared with the wild-type(WT)plant,RIN mutants had different root exudate profiles,which were associated with distinct changes in microbiome composition and diversity.Specifically,the relative abundances of antibiosis-associated genes and pathogensuppressing Actinobacteria(Streptomyces)were clearly lower in the rhizosphere of rin mutants.The composition,diversity,and suppressiveness of rin plant microbiomes could be restored by the application of 3-hydroxyflavone and riboflavin,which were exuded in much lower concentrations by the rin mutant.Interestingly,RIN-mediated effects on root exudates,Actinobacteria,and disease suppression were evident from the seedling stage,indicating that RIN plays a dual role in the early assembly of diseasesuppressive microbiota and late fruit development.Collectively,our work suggests that,while plant disease resistance is a complex trait driven by interactions between the plant,rhizosphere microbiome,and the pathogen,it can be indirectly manipulated using"prebiotic"compounds that promote the recruitment of disease-suppressive microbiota.

Trilayered Fibrous Dressing with Wettability Gradient for Spontaneous and Directional Transport of Massive Exudate and Wound Healing Promotion

Excessive exudate at wound sites increases treatment difficulty and severely decelerates the healing process.In wound exu-date management,dressings with unidirectional liquid transport capability have exhibited enormous potential.However,it remains challenging to improve the one-way liquid transport efficiency.Herein,a trilayered fibrous dressing is constructed by sequentially electrospinning polyurethane(PU)and polyvinylidene fluoride(PVDF)onto cotton fabric.Through hot pressing,a stable wettability gradient is formed across the PVDF/PU/cotton dressing due to the melting and bridging of PU nanofib-ers.The trilayered dressing exhibited rapid unidirectional transport with water penetrating from the hydrophobic side to the hydrophilic side in 6 s.The hydrostatic pressure from the hydrophilic side to the hydrophobic side is 569%higher than that from the hydrophobic side to the hydrophilic side,indicating that the dressing has a profound unidirectional conductivity.In vivo experiments demonstrates that the trilayered dressing can accelerate the wound healing process,especially in the early stages of wound occurrence,by quickly draining the excessive exudate.This study provides a new method to construct wound dressings with wettability gradients,which are advantageous for efficient exudate removal.

Bioassay and Identification of Root Exudates of Three Fruit Tree Species

A laboratory bioassay was designed to determine the aileiopathic potential of root exudates of three fruit tree species on apple germination. The results showed that root exudates of apple （Malus pumila L.） and peach （Prunus persica L.）, each at concentrations of 0.02 and 0.2 mg/L, inhibited germination and radicle growth of apple seeds by 56.7%, 60.7%, 51.5%, and 59.3%, respectively. The corresponding shoot growth inhibition rate was 49.5%, 46.7%, 36. 4%, and 44%, respectively. Root exudates of jujube （Ziziphus jujuba Mill.） had no significant effect on apple seeds. Qualitative determination of root exudates of apple, peach, and jujube tree was developed with gas chromatography-mass spectrometry. The root exudates of apple seedlings mainly contain organic acids, glycol, esters, and benzenphenol derivatives. Peach root exudates contained phenolic acids and benzenphenoi derivatives in addition to two unidentified compounds. The root exudates of jujube did not contain any phenolic acids.

Subcellular distribution and chemical form of Pb in hyperaccumulator Arenaria orbiculata and response of root exudates to Pb addition

Solution culture was conducted in order to understand accumulation characteristics and chemical forms of Pb in Arenaria orbiculata （A. orbiculata） and the response of root exudates to Pb addition. The results showed that： 1） Pb contents in the shoot and root of A. orbiculata increased with increasing in Pb concentrations in solution. 2） The contents of Pb chemical forms under Pb addition followed as： HAc extractable fraction＇（FriAC）〉 HC1 extractable fraction （FHcl）〉 NaCl extractable fraction （FNacl） 〉 ethanol-extractable fraction （FE） 〉 water extractable fraction （Fw）. 3） Increased Pb level in the medium caused increases in Pb contents in the four subcellular fractions of shoots and roots, with most accumulation in FIV （Fraction ＇IV, sbluble fraction） in shoots and FI （Fraction I, cell wall fraction） in roots. 4） Contents of soluble sugar and free amino acid of root exudates increased with increasing Pb concentration in solution. Significantly positive correlations between Pb and contents of soluble sugar and free amino acid were observed. 5） With Pb concentrations in solution, low molecular weight organic acids （LMWOAs） contents followed the tendency： tartaric acid 〉 acetic acid 〉 malic acid 〉 citric acid. Significantly positive correlation was observed between Pb and citric acid contents. The results indicate that soluble sugars, free amino acid and citric acid in root exudates of A.orbiculata facilitate the absorption and accumulation of Pb, which exist in NaCl-, HCI- and HAc- extractable Pb forms, FI and FIV fractions, resulting in tolerance of A.orbiculata to Pb.