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1.
Polycyclic aromatic hydrocarbons (PAHs) are harmful persistent organic pollutants, while the high-molecular-weight (HMW) PAHs are even more detrimental to the environment and human health. However, microbial anaerobic degradation of HMW PAHs has rarely been reported. One facultative anaerobe Pseudomonas sp. JP1 was isolated from Shantou Bay, Shantou, China, which could degrade a variety of HMW PAHs. After 40 days cultivation with strain JP1, anaerobic biodegradation rate of benzo[a]pyrene (BaP), fluoranthene, and phenanthrene was 30, 47, and 5 %, respectively. Consumption of nitrate as the electron acceptor was confirmed by N-(1-naphthyl) ethylenediamine spectrophotometry. Supplementation of sodium sulfite, maltose, or glycine, and in a salinity of 0–20 ‰ significantly stimulated anaerobic degradation of BaP. Lastly, the anaerobic degradation metabolites of BaP by strain JP1 were investigated using GC/MS, and the degradation pathway was proposed. This study is helpful for further studies on the mechanism of anaerobic biodegradation of PAHs.  相似文献   

2.
Development of successful bioremediation strategies for environments contaminated with recalcitrant pollutants requires in-depth knowledge of the microorganisms and microbial processes involved in degradation. The response of soil microbial communities to three polycyclic aromatic hydrocarbons, phenanthrene (3-ring), fluoranthene (4-ring) and benzo(a)pyrene (5-ring), was examined. Profiles of bacterial, archaeal and fungal communities were generated using molecular fingerprinting techniques (TRFLP, ARISA) and multivariate statistical tools were employed to interpret the effect of PAHs on community dynamics and composition. The extent and rate of PAH removal was directly related to the chemical structure, with the 5-ring PAH benzo(a)pyrene degraded more slowly than phenathrene or fluoranthene. Bacterial, archaeal and fungal communities were all significantly affected by PAH amendment, time and their interaction. Based on analysis of clone libraries, Actinobacteria appeared to dominate in fluoranthene amended soil, although they also represented a significant portion of the diversity in phenanthrene amended and unamended soils. In addition there appeared to be more γ-Proteobacteria and less Bacteroidetes in soil amended with either PAH compared to the control. The soil bacterial community clearly possessed the potential to degrade PAHs as evidenced by the abundance of PAH ring hydroxylating (PAH-RHDα) genes from both gram negative (GN) and gram positive (GP) bacteria in PAH-amended and control soils. Although the dioxygenase gene from GP bacteria was less abundant in soil than the gene associated with GN bacteria, significant (p < 0.001) increases in the abundance of the GP PAH-RHDα gene were observed during phenanthrene and fluoranthene degradation, whereas there was no significant difference in the abundance of the GN PAH-RHDα gene during the course of the experiment. Few studies to-date have examined the effect of pollutants on more than one microbial community in soil. The current study provides information on the response of soil bacterial, archaeal and fungal communities during the degradation of three priority pollutants and contributes to a knowledge base that can inform the development of effective bioremediation strategies for contaminated sites.  相似文献   

3.
Polycyclic aromatic hydrocarbons (PAHs) are xenobiotic compounds, which being degraded by chemical, physical or biological methods. The latter is the safest and the cheapest one. Two bacterial strains ASU-01 and ASU-016 were isolated from different Egyptian petroleum contaminated sites. They were genetically identified based on the analysis of the nucleotide sequences of the 16S ribosomal PNA gene and the phylogenetic tree as Enterobacter hormaechei and Pseudomonas pseudoalcaligenes respectively. When pyrene as high molecular weight (HMW)-PAH was added as a sole carbon source, both strains could degrade it with efficiency 77.7 and 83.7% within 15 days of incubation, respectively. However, when it was mixed with low molecular weight (LMW)-PAHs, two opposite phenomena appeared. The first one was enhancement, which occurred with ASU-01. This strain shifted pyrene efficiency to 98.5%. The second phenomenon was inhibition occurred with ASU-016 which completely retarded pyrene degradation. Naphthalene dioxygenase (nahAc), and catechol dioxygenases (C12O and C23O) genes were detected in the two strains based on PCR. The detected genes were confirmed by determining the different specific activities of their translated protein (enzymes) on different PAHs. The maximum values of biosurfacatant production activity and cell-surface and percentage of cell-surface hydrophobicity (CSH) were detected during the exponential phase. These latter factors increased the bioavailability and consequently, the assimilation of PAHs.  相似文献   

4.
A controlled field experiment was conducted to assess the potential for fermentative–methanogenic biostimulation (by ammonium-acetate injection) to enhance biodegradation of benzene, toluene, ethylbenzene and xylenes (BTEX) as well as polycyclic aromatic hydrocarbons (PAHs) in groundwater contaminated with biodiesel B20 (20:80 v/v soybean biodiesel and diesel). Changes in microbial community structure were assessed by pyrosequencing 16S rRNA analyses. BTEX and PAH removal began 0.7 year following the release, concomitantly with the increase in the relative abundance of Desulfitobacterium and Geobacter spp. (from 5 to 52.7 % and 15.8 to 37.3 % of total Bacteria 16S rRNA, respectively), which are known to anaerobically degrade hydrocarbons. The accumulation of anaerobic metabolites acetate and hydrogen that could hinder the thermodynamic feasibility of BTEX and PAH biotransformations under fermentative/methanogenic conditions was apparently alleviated by the growing predominance of Methanosarcina. This suggests the importance of microbial population shifts that enrich microorganisms capable of interacting syntrophically to enhance the feasibility of fermentative–methanogenic bioremediation of biodiesel blend releases.  相似文献   

5.
The effects of benzo(a)pyrene (Bap) (0.03, 0.3 and 3 μg L?1) and chrysene (CHR) (0.3, 2.1 and 14.7 μg L?1) on the function of the immune system of juvenile white shrimp Litopenaeus vannamei were determined under laboratory conditions. This included the total hemocyte count (THC) in the hemolymph, phagocytic activityand pro-phenoloxidase (pro-PO) activity of the hemocyte, phenoloxidase (PO) activity, α2-macroglobulin (α2-M) activity, bacteriolytic activity and antibacterial activity in the hemolymph. The results showed that BaP and CHR could inhibit the immune function of L. vannamei significantly under high concentration BaP and CHR exposure. The results of this study indicated that the immunotoxicity of PAHs in a descending order was BaP>CHR. Moreover, the results indicated the THC in hemolymph, pro-PO activity and phagocytic activity of hemocyte, and bacteriolytic activity in hemolymphcould be used as potentially suitable biomarkersfor early warning indication of PAHs toxicity, this could provide useful information for toxic risk assessment of environmental pollutants.  相似文献   

6.
The co-occurrence of polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) is very common in contaminated environments. It is of paramount importance and great challenge to exploit a bioremediation to remove PAHs in these environments with combined pollution. We approached this question by probing the influence of HMs coexisting with PAHs on the removal of PAHs by Acremonium sp. P0997 possessing metal resistance. A removal capability for naphthalene, fluorene, phenanthrene, anthracene, and fluoranthenepresentalone (98.6, 99.3, 89.9, 60.4, and 70 %, respectively) and in a mixture (96.9, 71.8, 67.0, 85.0, and 87.9 %, respectively) was achieved in mineral culture inoculated with Acremonium sp. P0997, and this strain also displayed high resistance to the individual HMs (Mn2+, Fe2+, Zn2+, Cu2+, Al3+, and Pb2+). The removal of individual PAHs existing in a mixture was differently affected by the separately tested HMs. Cu2+enhanced the partition process of anthracene to dead or alive mycelia and the contribution of the biosorption by this strain but imposed a little negative influence on the contribution of biodegradation to the total removal of anthracene individually in a culture. However, Mn2+ had an inhibitory effect on the partition process of anthracene to dead or alive mycelia and decreased the contributions of both biosorption and biodegradation to the total anthracene removal. This work showcased the value of fungi in bioremediation for the environments with combined pollution, and the findings have major implications for the bioremediation of organic pollutants in metal-organic mixed contaminated sites.  相似文献   

7.
Microbial polysaccharides have a wide range of functional properties and show high relevance in industrial applications. The possibility to create tailor-made polysaccharides by genetic engineering will further enhance the product portfolio and may open new fields of application. Here, we have examined in detail the recently sequenced genome of the welan-producing strain Sphingomonas sp. ATCC 31555 to identify the complete welan cluster and further genes involved in EPS production. The corresponding genes were compared on the nucleotide and amino acid sequence level to the EPS clusters of the described gellan-producing Sphingomonas elodea ATCC 31461, diutan-producing Sphingomonas sp. ATCC 53159, and the S-88-producing Sphingomonas sp. ATCC 31554 strains. We also compared the previously mentioned strains to each other and included the genes upstream of the main cluster in gellan and welan cluster. The cluster organization of Sphingomonas strain S-7 was also compared based on previous hybridization experiments, without nucleotide sequences. We have found that the occurrence of genes in all biosynthesis clusters is connected to the structures of the various produced sphingans. Along these lines, homologous genes responsible for the assembly of the identical repeating unit generally show high sequence identity, whereas genes for putative side chain attachment urf31, urf31.4, and urf34 vary more in distinct areas. Moreover, gene clusters for biosynthesis of diutan, welan, gellan, and S-88 as well as S-7 are similar in general organization but differ in location and arrangement of some genes. Finally, we summarized genetic and mutational engineering approaches toward modified sphingan variants as described in literature.  相似文献   

8.
The diversity and physiological characteristics of culturable bacteria associated with lichens from different habitats of the Arctic and Antarctica were investigated. The 68 retrieved isolates could be grouped on the basis of their 16S rRNA gene sequences into 26 phylotypes affiliated with the phyla Actinobacteria, Bacteroidetes, Deinococcus-Thermus, and Firmicutes and with the classes Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. Isolates belonging to the Alphaproteobacteria were the most abundant, followed by those belonging to Actinobacteria, Betaproteobacteria, Gammaproteobacteria, Bacteroidetes, Firmicutes, and Deinococcus-Thermus. Phylogenetic analysis showed that approximately 21 % of the total isolates represented a potentially novel species or genus (≤97 % sequence similarity). Strains belonging to the genera Sphingomonas, Frondihabitans, Hymenobacter, and Burkholderia were recovered from lichen samples from both geographic locations, implying common and important bacterial functions within lichens. Extracellular protease activities were detected in six isolates, affiliated with Burkholderia, Frondihabitans, Hymenobacter, Pseudomonas, and Rhodanobacter. Extracellular lipase activities were detected in 37 isolates of the genera Burkholderia, Deinococcus, Frondihabitans, Pseudomonas, Rhodanobacter, Sphingomonas, and Subtercola. This is the first report on the culturable bacterial diversity present within lichens from Arctic and Antarctica and the isolates described herein are valuable resources to decode the functional and ecological roles of bacteria within lichens. In addition, the low similarity (≤97 %) of the recovered isolates to known species and their production of cold-active enzymes together suggest that lichens are noteworthy sources of novel bacterial strains for use in biotechnological applications.  相似文献   

9.
Polycyclic aromatic hydrocarbons (PAHs) are one of the major pollutants in soils in oil exploring areas. Biodegradation is the major process for natural elimination of PAHs from contaminated soils. Functional genes can be used as biomarkers to assess the biodegradation potential of indigenous microbial populations. However, little is known about the distribution of PAH-degrading genes in the environment. The links between environmental parameters and the distribution of PAH metabolic genes remain essentially unclear. The present study investigated the abundance and diversity of naphthalene dioxygenase genes in the oil-contaminated soils in the Shengli Oil Field (China). Spatial variations in the density and diversity of naphthalene dioxygenase genes occurred in this area. Four different sequence genotypes were observed in the contaminated soils, with the predominance of novel PAH-degrading genes. Pearson’s correlation analysis illustrated that gene abundance had positive correlations with the levels of total organic carbon and aromatic hydrocarbons, while gene diversity showed a negative correlation with the level of polar aromatics. This work could provide some new insights toward the distribution of PAH metabolic genes and PAH biodegradation potential in oil-contaminated ecosystems.  相似文献   

10.
11.
Complex molecular changes that occur during prostate cancer (PCa) progression have been described recently. Whole genome sequencing of primary PCa samples has identified recurrent gene deletions and rearrangements in PCa. Specifically, these molecular events disrupt the gene loci of phosphatase and tensin homolog (PTEN) and membrane-associated guanylate kinase inverted-2 (MAGI2). In the present study, we analyzed the expression profile of MAGI2 gene in a cohort of clinical PCa (n = 45) and benign prostatic hyperplasia (BPH) samples (n = 36) as well as three PCa cell lines. We also studied the expression of PCa-related genes, including PTEN, NKX3.1, SPINK1, DD3, AMACR, ERG, and TMPRSS2-ERG fusion in the same samples. The expression of MAGI2 mRNA was significantly down-regulated in PC3, LNCaP and DU-145 PCa cell lines (p = 0.000), and also in clinical tumor samples (Relative expression = 0.307, p = 0.002, [95 % CI 0.002–12.08]). The expression of PTEN, NKX3.1, SPINK1, DD3, and AMACR genes was significantly deregulated in prostate tumor samples (p range 0.000–0.044). A significant correlation was observed between MAGI2 and NKX3.1 expression in tumor samples (p = 0.006). Furthermore, the inclusion of MAGI2 in the gene panel improved the accuracy for discrimination between PCa and BPH samples with the sensitivity and specificity of 0.88 [CI 0.76–0.95] and 0.83 [CI 0.68–0.92], respectively. The data presented here suggest that MAGI2 gene can be considered as a novel component of gene signatures for the detection of PCa.  相似文献   

12.
Effect of hydrocortisone, NaF, and FeSO4 on ligninolytic and phosphatase activity of the fungus Lentinus (Panus) tigrinus VKM F-3616D was investigated. Hydrocortisone and NaF were shown to inhibit the enzymes of the ligninolytic complex—laccase (EC 1.10.3.2), secretory peroxidase (EC 1.11.1.7), and Mn peroxidase (EC 1.11.1.13). FeSO4 exhibited no significant effect on the activity of these enzymes. Decreased activity of the enzymes of the ligninolytic complex was associated with inhibition of the activity and changes in the substrate specificity of phospholipase A2 (EC 3.1.1.4) in the presence of hydrocortisone of NaF. Cultivation of L. tigrinus in the presence of these compounds resulted in higher affinity of this enzyme to saturated fatty acids, while in the control and in the presence of FeSO4 affinity to unsaturated fatty acids was higher.  相似文献   

13.
The genetic factors of cancer predisposition remain elusive in the majority of familial and/or early-onset cases of breast cancer (BC). This type of BC is promoted by germ-line mutations that inactivate BRCA1 or BRCA2. On the other hand, recent studies have indicated that alterations in the levels of miRNA expression are linked to this disease. Although BRCA1 and BRCA2 gene mutations have been reported to commonly lead to alterations in genes that encode cancer-related proteins, little is known regarding the putative impact of these mutations on noncoding miRNAs. In the present study, we aimed to determine whether miRNA dysregulation is involved in the pathogenesis of BRCA-mutated BC. An expression analysis of 14 human miRNAs previously shown to be related to BC diagnosis, prognosis, and drug resistance was conducted using tissues from 60 familial and/or early-onset patients whose peripheral blood samples had been screened for BRCA1 and BRCA2 mutations through sequence analysis. Let-7a and miR-335 expression levels were significantly downregulated in the tumors of patients with a BRCA mutation compared with those of patients without a BRCA mutation (P = 0.04 and P = 0.02, respectively). Our results defined the associations between the expression status of let-7a and miR-335 and BRCA mutations. The expression analysis of these miRNAs might be used as biomarkers of the BRCA mutation status of early-onset and/or familial BC.  相似文献   

14.
The mahseers are an important group of fishes endemic to Asia with most species considered threatened. Conservation plans to save declining wild populations are hindered by unstable taxonomy, and detailed systematic review could form a solid platform for future management and conservation. D-loop and cytochrome c oxidase I (COI) mtDNA sequences were examined in nine mahseer species of Tor, Neolissochilus, and Naziritor. Pseudogenes amplified in a portion of the species limited the utility of the D-loop region. ABGD analysis, NJ, ML, and MP methods and genetic distance (TrN?+?I?+?G) using COI data revealed concordant species delimiting patterns. The three genera were monophyletic, separated as distinct clades (TrN?+?I?+?G 0.064 to 0.106), and Naziritor was flagged as a separate genus, distinct from Puntius (TrN?+?I?+?G 0.196). Out of seven nominal species known for Tor cogeners from India, only five were recovered with mtDNA data (TrN?+?I?+?G 0.000 to 0.037) and two species could not be distinguished with the molecular data set employed. Tor mosal, synonymized as Tor putitora, was rediscovered as a distinct species (TrN?+?I?+?G 0.031) based on its type locality. Tor mussulah was confirmed as a separate species (TrN?+?I?+?G 0.019 to 0.026). Two valid species, Tor macrolepis and T. mosal mahanadicus, were not distinct from T. putitora (TrN?+?I?+?G 0.00). The high divergence with mtDNA data failed to validate T. mosal mahanadicus as a subspecies of T. mosal (TrN?+?I?+?G 0.031). Morphological outliers discovered within the distribution range of Tor tor (TrN?+?I?+?G 0.022 to 0.025) shared the same lineage with T. putitora (TrN?+?I?+?G 0.002 to 0.005), indicating a new extended distribution of the Himalayan mahseer T. putitora in the rivers of the Indian central plateau. The findings indicate the need for integrating molecular and morphological tools for taxonomic revision of the Tor and Naziritor genera, so that taxa are precisely defined for accurate in situ and ex situ conservation decisions.  相似文献   

15.
The N 1-methyladenosine residue at position 58 of tRNA is found in the three domains of life, and contributes to the stability of the three-dimensional L-shaped tRNA structure. In thermophilic bacteria, this modification is important for thermal adaptation, and is catalyzed by the tRNA m1A58 methyltransferase TrmI, using S-adenosyl-l-methionine (AdoMet) as the methyl donor. We present the 2.2 Å crystal structure of TrmI from the extremely thermophilic bacterium Aquifex aeolicus, in complex with AdoMet. There are four molecules per asymmetric unit, and they form a tetramer. Based on a comparison of the AdoMet binding mode of A. aeolicus TrmI to those of the Thermus thermophilus and Pyrococcus abyssi TrmIs, we discuss their similarities and differences. Although the binding modes to the N6 amino group of the adenine moiety of AdoMet are similar, using the side chains of acidic residues as well as hydrogen bonds, the positions of the amino acid residues involved in binding are diverse among the TrmIs from A. aeolicus, T. thermophilus, and P. abyssi.  相似文献   

16.
Bioaerosols are transported from warm regions and lower latitudes of the planet to colder regions and higher latitudes, such as the Chilean Patagonia. The role of bioaerosols deposition in remote lake ecosystems is a potentially important process, but it has not yet been fully studied. The aim of this study was to detect and characterize potentially pathogenic viable microorganisms in bioaerosols in a pristine area. Samples were collected from the air, at three remote lakes in the Chilean Patagonia, using a sterile filtration system equipped with 0.2-μm-pore-size nitrocellulose filters. The bacterial community present in bioaerosols was studied using scanning electron microscopy (SEM) and denaturing gradient gel electrophoresis. Isolates were identified and characterized for phenotypic and 16S rDNA analysis and antibiotic resistance. SEM observations of samples from each lake showed the presence of bacteria with different morphologies, and after culturing, the identification results revealed that they were strains of Acinetobacter, Alcaligenes, Edwarsiella, Pseudomonas, Burklolderia, Moraxella, Sphingomonas and CDC NO-1. CDC NO-1, uncommonly isolated worldwide, stands out from the rest of the isolates because it is a rarely found bacterium so far associated with dog and cat bites and was found at two out of three pristine lakes studied (Alto and Verde). This work demonstrates, for the first time, the presence of CDC NO-1, a clinically important Gram-negative microorganism, in bioaerosols and first report of CDC-NO1 isolation in Chile. Besides its presence in remote lakes, its antibiotic resistance is worth mentioning.  相似文献   

17.
18.
Hepatocellular carcinoma (HCC) is a very aggressive neoplasia requiring early and accurate diagnosis to improve patient outcomes with timely treatment. The liver is also very frequently colonized by metastases, and the most frequent differential diagnosis is HCC against intrahepatic cholangiocarcinoma or metastatic adenocarcinoma. Metabolomics is a powerful tool for identification of altered biomarkers in cancer, and to evaluate the efficacy of drug treatments. Here we analyzed by HILIC-MS/MS methylated arginines, basic amino acids (Arg, Cit, Orn), and their ratios in the extracts of primary HCC tissues, liver metastases from colorectal carcinoma (MET), cirrhotic related hepatitis-C-virus (CIR), and non-cirrhotic normal liver (NT) adjacent tissues. We found high levels of Arg (p < 0.0001) and Arg/Orn (p < 0.01) in MET compared to other tissues. In MET, compared to NT and CIR, Arg concentration was fivefold higher, while in HCC it was twofold higher. ADMA increased twofold compared to NT and CIR, while in HCC it was 50 % higher. Arg/Cit and ADMA/SDMA ratios were significantly higher in MET compared to NT and CIR (p < 0.005). Arg/Orn, Arg/Cit, and ADMA/SDMA ratios increased progressively from NT, CIR, HCC, to MET tissues. Arg/Cit correlated significantly with Arg/Orn ratios (r = 0.77; p < 0.0001), and discriminates tumor from non-tumor samples. In addition, the discriminant lactate/glucose ratio we previously found by NMR, also correlated significantly with the Arg levels (r = 0.64; p < 0.0001), and discriminated MET from all other tissues. The results indicated that Arg in MET is higher than other tissue classes, suggesting that, together with the lactate/glucose ratio, it can be considered a further biomarker for HCC-metastases differentiation.  相似文献   

19.
This study was conducted to determine effects of dietary supplementation with 1 % l-glutamine for 14 days on the abundance of intestinal bacteria and the activation of intestinal innate immunity in mice. The measured variables included (1) the abundance of Bacteroidetes, Firmicutes, Lactobacillus, Streptococcus and Bifidobacterium in the lumen of the small intestine; (2) the expression of toll-like receptors (TLRs), pro-inflammatory cytokines, and antibacterial substances secreted by Paneth cells and goblet cells in the jejunum, ileum and colon; and (3) the activation of TLR4-nuclear factor kappa B (NF-κB), mitogen-activated protein kinases (MAPK), and phosphoinositide-3-kinases (PI3K)/PI3K-protein kinase B (Akt) signaling pathways in the jejunum and ileum. In the jejunum, glutamine supplementation decreased the abundance of Firmicutes, while increased mRNA levels for antibacterial substances in association with the activation of NF-κB and PI3K-Akt pathways. In the ileum, glutamine supplementation induced a shift in the Firmicutes:Bacteroidetes ratio in favor of Bacteroidetes, and enhanced mRNA levels for Tlr4, pro-inflammatory cytokines, and antibacterial substances participating in NF-κB and JNK signaling pathways. These results indicate that the effects of glutamine on the intestine vary with its segments and compartments. Collectively, dietary glutamine supplementation of mice beneficially alters intestinal bacterial community and activates the innate immunity in the small intestine through NF-κB, MAPK and PI3K-Akt signaling pathways.  相似文献   

20.
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