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1.
The effect of phenanthrene, a polycyclic aromatic hydrocarbon (PAH) at concentrations of 0, 10, and 100 mg/kg and the bacterium Sinorhizobium meliloti P221 on root exudation of Sorghum bicolor L. Moench was studied in laboratory vegetative experiments. Inoculation of the bacterium promoted plant resistance to the pollutant stress and increased their acclimation rate and biomass formation. The ability of this microorganism to produce a phytohormone, indolyl-3-acetic acid, and to degrade phenanthrene, resulted in morphological changes of the plant root system and in the changed intensity of root exudation. In root exudates of sorghum, enzyme activities towards the metabolites formed during microbial degradation of PAH were revealed, which is indicative of a direct involvement of plants in PAH degradation in the rhizosphere as well as of the coupled plant-microbial metabolism in the course of xenobiotic degradation in the root zone. In phenanthrene-contaminated soil, sorghum was found to support selectively the development of the S. meliloti P221 population.  相似文献   

2.
From the roots and root exudates of 3-week-old plants of alfalfa (Medicago sativa L.), anionic and cationic peroxidases differing in principal physicochemical and catalytic properties were isolated and purified. Main features of anionic peroxidases detected in the roots and root exudates were identical. Phenanthrene present in the soil used for alfalfa growing influenced the number of forms and activity of peroxidases in crude enzyme preparations but did not affect the properties of pure enzymes. In the presence of a synthetic mediator, purified peroxidases can oxidize phenanthrene and its derivatives, including potential microbial metabolites of polycyclic aromatic hydrocarbons (PAH). The fact that the enzymes excreted in root exudates in a purified form can oxidase PAH proves their participation in degradation of PAH and their microbial metabolites in alfalfa rhizosphere. These new data indicate that the processes of plant and microbial degradation of pollutants in the rhizosphere are coupled; they are relevant to understanding the molecular mechanisms of degradation of persistent pollutants by plant-microbial complexes.  相似文献   

3.
From the leaves of three urban trees (Tilia sp., Acer sp., and Fraxinus sp.), 180 strains degrading phenanthrene, naphthalene, and salicylate were isolated by direct plating and enrichment cultures. The leaves of each tree species were characterized by a specific profile of aromatic hydrocarbon-degrading microflora. Members of the type Actinobacteria were predominant in the case of direct plating on media with phenanthrene and naphthalene. Enrichment cultures with phenanthrene and salicylate were shown to yield microbial consortia, the composition of which changed with time. Members of the type Proteobacteria were predominant in these consortia. No plasmids of polycyclic aromatic hydrocarbon degradation of the P-7 and P-9 incompatibility groups were revealed in the studied strains.  相似文献   

4.
Diversity of the oil-degrading microbial strains isolated from the water and sediments of the Gulf of Finland (Baltic Sea) in winter and in summer was studied. Substrate specificity of the isolates for aliphatic and aromatic hydrocarbons was studied. The isolates belonged to 32 genera of the types Proteobacteria (alpha-, beta-, and gammaproteobacteria), Actinobacteria,Firmicutes, and Bacteroidetes. Seasonal variations of the oil-degrading microbial communities was revealed. The presence of the known genes responsible for the degradation of oil aliphatic and aromatic hydrocarbons was determined. The alkB sequence of the alkane hydroxylase gene was found in ~16% of the studied strains. The sequence of the phnAc phenanthrene 3,4- dioxygenase was found in Sphingobacterium sp. and Arthrobacter sp. isolates retrieved in winter and summer. In five Pseudomonas sp. strains from winter samples, the classical operons of naphthalene degradation (nah) were localized in catabolic plasmids, of which three belonged to IncР-9, one, to IncР-7, and two to an unidentified incompatibility group. Burkholderia and Delftia strains contained the operons for naphthalene degradation via salicylate and gentisate (nag). The presence of nag genes has not been previously reported for Delftia spp. strains. The sequences of the nagG salicylate 5-hydroxylase gene were also found in Achromobacter, Sphingobacterium, and Stenotrophomonas strains.  相似文献   

5.
Degradation of phenanthrene by strains Pseudomona, Moscow, KMK, 2004simova, I.A. and Chernov, I.s putida BS3701 (pBS1141, pBS1142), Pseudomonas putida BS3745 (pBS216), and Burkholderia sp. BS3702 (pBS1143) were studied in model soil systems. The differences in accumulation and uptake rate of phenanthrene intermediates between the strains under study have been shown. Accumulation of 1-hydroxy-2-naphthoic acid in soil in the course of phenanthrene degradation by strain BS3702 (pBS1143) in a model system has been revealed. The efficiency of phenanthrene biodegradation was assessed using the mathematical model proposed previously for assessment of naphthalene degradation efficiency. The efficiency of degradation of both phenanthrene and the intermediate products of its degradation in phenanthrene-contaminated soil is expected to increase with the joint use of strains P. Putida BS3701 (pBS1141, pBS1142) and Burkholderia sp. BS3702 (pBS1143).  相似文献   

6.
Concentrations of toxic metals viz. mercury (Hg), cadmium (Cd) and lead (Pb) were evaluated in four species of fishes (Sardinella longiceps, Selaroides leptolepis, Epinephelus quoyanus and Lethrinus lentjan), one species of shrimp (Penaeus semisulcatus) and one species of crab (Portunus sanguinolentus) sampled from Thoothukudi, Keelakarai and Veerapandian pattinam of Gulf of Mannar, Southeast coast of India. Results revealed accumulation of these metals in the following order Hg > Cd > Pb. Hg concentration was found to be higher in Po. sanguinolentus followed by E. quoyanus, Pe. semisulcatus and L. lentjan however, the same was absent in Sa. longiceps and Se. leptolepis. Cd concentration was recorded in decreasing order in Po. sanguinolentus > Pe. semisulcatus > L. lentjen > E. quoyanus > Sa. longiceps > Se. leptolepis. Pb was detectable only in four species. Results of One-way ANOVA revealed significant variations (p < 0.05) in accumulation of Cd in Sa. longiceps, Se. leptolepis and Pe. semisulcatus and Hg in E. quoyanus, L. lentjan and Po. sanguinolentus. Variations noted in Pb were not statistically significant throughout.  相似文献   

7.
In a previous study, the synbiotic combination of selected Lactobacillus gasseri strains and Cudrania tricuspidata leaf extract (CT) was shown to significantly improve the functionality of fermented milk, and the greatest synbiotic effect was exhibited with L. gasseri 505. The aim of the present study was to investigate the growth kinetics and fermentation metabolism of this specific synbiotic combination. Fermentation was carried out in synthetic media and milk with or without CT supplementation using L. gasseri 505. Whole genome sequencing and comparative genomics analyses were conducted to verify the novelty of strain. Titratable acidity, pH, microbial population, and organic acid production were measured during the fermentation period. The addition of CT accelerated the acidification rate, supporting the growth of L. gasseri 505, and the production of fermentation metabolites such as lactic acid and pyruvic acid also significantly increased during fermentation of both of CT-supplemented synthetic media and milk. In particular, the formic acid and propionic acid in CT were significantly utilized during fermentation of milk by L. gasseri 505. Moreover, the antioxidant capacity of CT-supplemented fermented milk increased due to the release of bioactive compounds until the exponential growth phase, after which the antioxidant activity declined due to degradation and loss of potency. Therefore, this study established that L. gasseri 505 efficiently utilized the CT-related nutrients during fermentation producing resulting metabolites with health-promoting effects, although it is necessary to control the fermentation time to obtain dairy products with optimum functionality.  相似文献   

8.
The study was aimed to analyze the relation between individual genotypes and allelic variants of SNPs g.2141C>G of growth hormone gene, g.914T>A and g.257A>G of growth hormone receptor gene with growth and reproduction traits and to evaluate the populationgenetic structure in Aberdeen-Angus cattle (Bos taurus L., 1758) sample of Eastern Ukraine according SNPs studied. Allele C of SNP g.2141C>G has a positive correlation with birth weight, body stature, bigger rump, udder and total exterior evaluation score, shorter calving interval and better calve birth weight and negative correlation with calve average daily gain. Allele T of SNP g.914T>A has positive correlation with the muscle and udder size; live weight in each age, average daily gain, weight and average daily gain of calves born conform to the principle AA>TTTA. SNP g.257A>G showed a positive correlation for G allele with muscle size. The population is in equilibrium for SNPs g.2141C>G and g.257A>G, and in disequilibrium for SNP g.914T>A. The analysis showed no linkage disequilibrium between SNPs g.914T>A and g.257A>G. Inbreeding coefficient FST in Aberdeen-Angus group studied was 16.1%.  相似文献   

9.
Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae) is a serious pest that attacks both germinating and seedling stages of a variety of cruciferous crops grown in the Central Coast of California. B. hilaris feeding on germinating seeds can cause severe stunting and plant mortality, and little is known about the feeding preference of B. hilaris for germinating seeds of major cruciferous hosts and varieties of hosts. No-choice and choice experiments were conducted in which germinating seeds in soilless and soil settings were exposed to B. hilaris adults for 7 days. Susceptibility scores were developed using B. hilaris feeding injury sites, distorted leaves, and deformed and dead plants to determine the overall B. hilaris preference for germinating host seeds. Based on the scores, the order of preference was arugula (Eruca sativa L.)?>?turnip (B. rapa L. var. rapa)?>?mizuna (B. rapa L. nipposinica)?>?kale (B. oleracea L. acephala)?>?choi (Brassica rapa L. var. chinensis)?>?broccoli (B. oleracea var. italica Plenck)?>?cauliflower (B. oleracea L. var. botrytis)?>?lettuce (Lactuca sativa L.)?>?sweet alyssum (Lobularia maritima [L.] Desv.). The lowest feeding injury was recorded on germinating lettuce and sweet alyssum seeds. Furthermore, no-choice and choice experiments were conducted with four varieties each of arugula and mizuna, twelve varieties each of kale and choi, and nine varieties/types of leafy Asian greens. The arugula varieties ‘Wild Rocket’ and ‘Spirit’ were more damaged by B. hilaris than other varieties tested. Among mizuna varieties, ‘Beira F1’ was more attractive to B. hilaris than ‘Scarlet’ or ‘Starbor F1.’ The choi varieties ‘Tokyo Bekana,’ ‘Feng Qing Choi F1,’ ‘Joi Choi F1,’ and ‘Win-Win Choi F1’ were more attractive than ‘Rosie F1.’ The leafy Asian greens variety ‘Carlton F1’ was more attractive to B. hilaris than ‘Yukina Savon,’ ‘Tatsoi OG,’ ‘Komatsuna Summerfest F1,’ ‘Red Rain F1,’ and ‘Shungiku.’ Therefore, the results suggest that not all varieties were equally susceptible to B. hilaris feeding and possibly be utilized for further field evaluation as a trap crop or developing more resistant varieties to B. hilaris.  相似文献   

10.
In order to study the mechanisms regulating the phenanthrene degradation pathway and the intermediate-metabolite accumulation in strain S. paucimobilis 20006FA, we sequenced the genome and compared the genome-based predictions to experimental proteomic analyses. Physiological studies indicated that the degradation involved the salicylate and protocatechuate pathways, reaching 56.3% after 15 days. Furthermore, the strain degraded other polycyclic aromatic hydrocarbons (PAH) such as anthracene (13.1%), dibenzothiophene (76.3%), and fluoranthene. The intermediate metabolite 1-hydroxy-2-naphthoic acid (HNA) accumulated during phenanthrene catabolism and inhibited both bacterial growth and phenanthrene degradation, but exogenous-HNA addition did not affect further degradation. Genomic analysis predicted 126 putative genes encoding enzymes for all the steps of phenanthrene degradation, which loci could also participate in the metabolism of other PAH. Proteomic analysis identified enzymes involved in 19 of the 23 steps needed for the transformation of phenanthrene to trichloroacetic-acid intermediates that were upregulated in phenanthrene cultures relative to the levels in glucose cultures. Moreover, the protein-induction pattern was temporal, varying between 24 and 96 h during phenanthrene degradation, with most catabolic proteins being overexpressed at 96 h—e. g., the biphenyl dioxygenase and a multispecies (2Fe–2S)-binding protein. These results provided the first clues about regulation of expression of phenanthrene degradative enzymes in strain 20006FA and enabled an elucidation of the metabolic pathway utilized by the bacterium. To our knowledge the present work represents the first investigation of genomic, proteomic, and physiological studies of a PAH-degrading Sphingomonas strain.  相似文献   

11.
12.

Background & Aims

Oak seedling establishment is difficult and may be partly explained by litter-mediated interactions with neighbors. Litter effects can be physical or chemical and result in positive or negative feedback effects for seedlings. Mediterranean species leaves contain high levels of secondary metabolites which suggest that negative litter effects could be important.

Methods

Seedlings of Quercus ilex and Quercus pubescens were grown for two years in pots with natural soil and litter inputs from 6 Mediterranean woody species, artificial litter (only physical effect) or bare soil.

Results

Litter types had highly different mass loss (41–80%), which correlated with soil organic C, total N and microbial activity. Litter of Q. pubescens increased soil humidity and oak seedlings aerial biomass. Litters of Cotinus coggygria and Rosmarinus officinalis, containing high quantities of phenolics and terpenes respectively, decomposed fast and led to specific soil microbial catabolic profiles but did not influence oak seedling growth, chemistry or mycorrhization rates.

Conclusions

Physical litter effects through improved soil humidity seem to be predominant for oak seedling development. Despite high litter phenolics content, we detected no chemical effects on oak seedlings. Litter traits conferring a higher ability to retain soil moisture in dry periods deserve further attention as they may be critical to explain plant-soil feedbacks in Mediterranean ecosystems.
  相似文献   

13.
Tartary buckwheat (Fagopyrum tataricum Gaertn.) is highly nutritious and an excellent dietary source of flavonoid compounds. Chalcone synthase (CHS) is the first key enzyme involved in flavonoid biosynthesis. Here, three putative CHS genes (designated as FtCHS1 (GU172165), FtCHS2 (KT284884), and FtCHS3 (KT284885) were isolated from tartary buckwheat. Nucleotide sequence analysis indicated that FtCHS1 and FtCHS2 each contained one intron of 444 bp and 157 bp, respectively. FtCHS3 included two introns, one of 86 bp and another of 73 bp. The results of quantitative real-time PCR (qRT-PCR) showed the FtCHSs expression presented the same pattern in the stems and flowers, with FtCHS1>FtCHS3>FtCHS2. A different tendency was found in leaves, with FtCHS3>FtCHS2>FtCHS1. However, there was no direct correlation between the three CHS expression and total flavonoids. Furthermore, high-performance liquid chromatography (HPLC) performance reveals rutin is the most abundant flavonoid in all tissues, leaves should be the main location for quercetin storage in tartary buckwheat.  相似文献   

14.
Necrotizing enterocolitis (NEC) is one of the most severe and unpredictable complications of prematurity. There are two possible mechanisms involved in the pathogenesis of NEC: individual inflammatory response and impaired blood flow in mesenteric vessels with secondary ischemia of the intestine. The aim of this study was to evaluate the possible relationship between polymorphisms: Il-1β 3953C>T, Il-6 ?174G>C and ?596G>A, TNFα ?308G>A, and 86 bp variable number tandem repeat polymorphism of interleukin-1 receptor antagonist (Il-1RN VNTR 86 bp) and three polymorphisms that may participate in arteries tension regulation and in consequence in intestine blood flow impairment: eNOS (894G>T and ?786T>C) and END-1 (5665G>T) and NEC in 100 infants born from singleton pregnancy, before 32 + 0 weeks of gestation, exposed to antenatal steroids therapy, and without congenital abnormalities. In study population, 22 (22%) newborns developed NEC. Surgery-requiring NEC was present in 7 children. Statistical analysis showed 20-fold higher prevalence of NEC in infants with the genotype TT [OR 20 (3.71–208.7); p = 0.0004] of eNOS 894G>T gene polymorphism. There was a higher prevalence of allele C carriers of eNOS 786T>C in patients with surgery-requiring NEC [OR 4.881 (1.33–21.99); p = 0.013]. Our investigation did not confirm any significant prevalence for NEC development in another studied genotypes/alleles. This study confirms the significant role of polymorphisms that play role in intestine blood flow. Identifying gene variants that increase the risk for NEC development may be useful in screening infants with inherent vulnerability and creating strategies for individualized care.  相似文献   

15.
We assessed drivers of ecological success along resource availability gradients for three invasive woody species: Prunus serotina Ehrh., Quercus rubra L. and Robinia pseudoacacia L. We aimed to check how much of invasion success, measured by invader biomass, is explained by propagule pressure and plant community invasibility. Using 3 years of observations from 372 study plots (100 m2 each) in temperate forests of Wielkopolski National Park (Poland) we investigated the hierarchy of predictors and partial dependencies using the random forest method. Our study indicated that propagule pressure explained more variance in success of invaders than invasibility—describing availability of resources and competitors in understory vegetation. We also found different responses of seedlings and saplings, connected with dependence on stored carbohydrates, which decreased seedling responses to resource availability gradients. However, resource availability (light and leaf litter predictors) had greater influence than predictors describing understory vegetation. Based on importance and response strength the species studied may be arranged by decreasing requirements for soil fertility and acidity: P. serotina?<?Q. rubra?<?R. pseudoacacia, whereas for light requirements and competition vulnerability the order is: P. serotina?>?Q. rubra?>?R. pseudoacacia. However, low light requirements of R. pseudoacacia may be biased by high proportion of sprouts supplied by parental trees. Results provide guidelines for effective management of invasive woody species in forest ecosystems and describe complex interactions between factors studied on ecological success of invaders.  相似文献   

16.
The effect of copper and nickel ions at concentrations of 1, 10, 25, 50, and 100 mg/L on morphometric and pigment indicators of the seedlings of narrowleaf water-plantain Alisma gramineum and seashore dock Rumex maritimus was studied. It was found that the pigment characteristics were more sensitive to nickel and copper than the morphometric characteristics. It was noted that copper started to be toxic at relatively low concentrations and lead to a significant degradation of the pigment complex compared with nickel. An inverse correlation was found in seedlings between metal concentrations in the medium and chlorophyll a (Chl a). It was shown that the synthesis of chlorophyll a was inhibited by metal salts more strongly than by chlorophyll b and carotenoids, and seedlings of seashore dock were more resistant to the action of the factors studied than seedlings of the narrowleaf water-plantain.  相似文献   

17.
The indigenous microorganisms responsible for degrading phenanthrene (PHE) in activated biosludge were identified using DNA-based stable isotope probing. Besides the well-known PHE degraders Burkholderia, Ralstonia, Sinobacteraceae and Arthrobacter, we for the first time linked the taxa Paraburkholderia and Kaistobacter with in situ PHE biodegradation. Analysis of PAH-RHDα gene detected in the heavy DNA fraction of 13C-PHE treatment suggested the mechanisms of horizontal gene transfer or inter-species hybridisation in PAH-RHD gene spread within the microbial community. Additionally, three cultivable PHE degraders, Microbacterium sp. PHE-1, Rhodanobacter sp. PHE-2 and Rhodococcus sp. PHE-3, were isolated from the same activated biosludge. Among them, Rhodanobacter sp. PHE-2 is the first identified strain in its genus with PHE-degrading ability. However, the involvement of these strains in PHE degradation in situ was questionable, due to their limited enrichment in the heavy DNA fraction of 13C-PHE treatment and lack of PAH-RHDα gene found in these isolates. Collectively, our findings provide a deeper understanding of the diversity and functions of indigenous microbes in PHE degradation.  相似文献   

18.
Types of the daily course of transpiration rate were studied in two-year old seedlings ofPinus silvestris L.,Picea excelsa L.,Larix decidua L.,Tilia cordata Mill., andAlnus glu-tinosa (L.) Gaertn. The curves illustrating the daily development of transpiration rate (Figs. 3 - 8) may be grouped in two types, showing a midday maximum (one-peak curves) and a midday depression (two-peak curves). Unlike herbaceous plants, the seedlings ofPinus silvestris L. were found to show, during the night-time, lower but not negligible values for the rate of transpiration (see Figs. 3 and 8). The following times are considered most suitable in determining the rate of transpiration for both herbs and woody species during the daylight: 09.0, 12.0, 14.0, and 17.0 hours. For the forest species seedlings further times are suitable for the night-time, as follows: 23.0, 01.0, and 06.0 hours. The rate of transpiration in the seedlings of Pinus silvestris attained very low levels at 3 and between 6 and 8 a.m. and between 6 and 8 p.m. (see Figs 3 and 8).  相似文献   

19.
Protective effect of the extracellular peptide fraction (reactivating factors, RF) produced by yeasts of various taxonomic groups (Saccharomyces cerevisiae, Kluyveromyces lactis, Candida utilis, and Yarrowia lipolytica) on probiotic lactic acid bacteria (LAB) Lactobacillus casei, L. acidophilus, and L. reuteri under bile salt (BS)-induced stress was shown. RF of all yeasts were shown to be of peptide nature; the active component of the S. cerevisiae RF was identified as a combination of low-molecular polypeptides with molecular masses of 0.6 to 1.5 kDa. The protective and reactivating effects of the yeast factors were not species-specific and were similar to those of the Luteococcus japonicus subsp. casei RF. In BS-treated cells of the tester bacteria, a protective effect was observed after 10-min preincubation of the LAB cell suspension with yeast RF: the number of surviving cells (CFU) was 2 to 4.5 times higher than in the control. The reactivating effect was observed when RF was added to LAB cell suspensions not later than 15 min after stress treatment. It was less pronounced than the protector effect, with the CFU number 1 to 3 times that of the control. Both the protector and the reactivating effects were most pronounced in the S. cerevisiae and decreased in the row C. utilis > K. lactis > Y. lipolytica. The efficiency of protective action of yeast RF was found to depend on the properties of recipient LAB cells, with the L. casei strain being most sensitive to BS treatment. In both variants, the highest protective effect of RF (increase in the CFU number) was observed for L. acidophilus, while the least pronounced one was observed for L. casei. The reasons for application of the LAB strains combining high stress resistance and high response to stress-protecting metabolites, including RF factors, as probiotics, is discussed.  相似文献   

20.
Metamifop is universally used in agriculture as a post-emergence aryloxyphenoxy propionate herbicide (AOPP), however its microbial degradation mechanism remains unclear. Consortium ME-1 isolated from AOPP-contaminated soil can degrade metamifop completely after 6 days and utilize it as the carbon source for bacterial growth. Meanwhile, consortium ME-1 possessed the ability to degrade metamifop stably under a wide range of pH (6.0–10.0) or temperature (20–42 °C). HPLC–MS analysis shows that N-(2-fluorophenyl)-2-(4-hydroxyphenoxy)-N-methyl propionamide, 2-(4-hydroxyphenoxy)-propionic acid, 6-chloro-2-benzoxazolinone and N-methyl-2-fluoroaniline, were detected and identified as four intermediate metabolites. Based on the metabolites identified, a putative metabolic pathway of metamifop was proposed for the first time. In addition, the consortium ME-1 was also able to transform or degrade other AOPP such as fenoxaprop-p-ethyl, clodinafop-propargyl, quizalofop-p-ethyl and cyhalofop-butyl. Moreover, the community structure of ME-1 with lower microbial diversity compared with the initial soil sample was investigated by high throughput sequencing. β-Proteobacteria and Sphingobacteria were the largest class with sequence percentages of 46.6% and 27.55% at the class level. In addition, 50 genera were classified in consortium ME-1, of which Methylobacillus, Sphingobacterium, Bordetella and Flavobacterium were the dominant genera with sequence percentages of 25.79, 25.61, 14.68 and 9.55%, respectively.  相似文献   

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