摘要：
The original version of this article unfortunately contained a mistake in the Fig. S1 of supplementary material. It is corrected with this erratum.
摘要：
Colletotrichum higginsianum causes anthracnose disease in a wide range of cruciferous crops and has been used as a model system to study plant-pathogen interactions and pathogenicity of hemibiotrophic plant pathogens. Conidiation, hyphae growth, appressorial development and appressorial penetration are significant steps during the infection process of C. higginsianum. However, the mechanisms of these important steps during infection remain incompletely understood. To further investigate the mechanisms of the plant-C. higginsianum interactions during infection progress, we characterized Cyclase-Associated Protein (ChCAP) gene. Deletion of the ChCAP gene resulted in reduction in conidiation and hyphal growth rate. The pathogenicity of DeltaChCAP mutants was significantly reduced with much smaller lesion on the infected leaves compared to that of wild type strain with typically water-soaked and dark necrotic lesions on Arabidopsis leaves. Further study demonstrated that the appressorial formation rate, turgor pressure, penetration ability and switch from biotrophic to necrotrophic phases decreased obviously in DeltaChCAP mutants, indicating that the attenuated pathogenicity of DeltaChCAP mutants was due to these defective phenotypes. In addition, the DeltaChCAP mutants sectored on PDA with abnormal, dark color, vesicle-like colony morphology and hyphae tip. Moreover, the DeltaChCAP mutants had a reduced intracellular cAMP levels and exogenous cAMP can partially rescue the defects of DeltaChCAP mutants in appressorial formation and penetration rate, but not in colony morphology, conidial shape and virulence, indicating that ChCAP is a key component in cAMP signaling pathway and likely play other roles in biology of C. higginsianum. In summary, our findings support the role of ChCAP in regulating conidiation, intracellular cAMP level, hyphal growth, appressorial formation, penetration ability and pathogenicity of this hemibiotrophic fungus.
摘要：
Acinetobacter sp. YT-02, a Gram-negative bacterium isolated from the activated sludge from a sodium N-cyclohexylsulfamate production plant, has the ability to degrade cyclohexylamine. It was classified as a member of Acinetobacter sp., a Gram-negative bacterium, sharing a 16S rRNA gene sequence identity of 99% with Acinetobacter guangdongensis strain 1NM-4. It could degrade 10 mmol/L cyclohexylamine within 22 h. Based on the identified metabolite, the metabolic pathway of cyclohexylamine could be postulated as it was degraded via cyclohexanone. Draft genome sequence of this strain (2,993, 647 bp of chromosome length) is presented here. We further identified the genes encoding the enzymes involved in cyclohexylamine oxidation to cyclohexanone and the subsequent downstream metabolic pathway of cyclohexanone oxidation. Strain YT-02 has the potentiality to be applied in the treatment of the pollutant cyclohexylamine, and it could also be treated as a research material to study the degradation mechanism of cyclohexylamine.
摘要：
The Gram-negative strain of Pseudomonas plecoglossicida NyZ12 isolated from soil has the ability to degrade cyclohexylamine (CHAM). The genes encoding CHAM degradation by gram-negative bacteria, however, have not been reported previously. In this study, ORFs predicted to encode CHAM degradation by NyZ12 were identified by bioinformatics analysis. Differential expression of the proposed ORFs was analyzed via RNA-seq and quantitative reverse transcription-PCR (qRT-PCR), using RNA extracted from NyZ12 cultured with or without CHAM addition. One CHAM-inducible ORF, RK21_02867 predicted to encode a cyclohexanone monooxygenase (ChnB) was disrupted, as were five ORFs, RK21_00425, RK21_02631, RK21_04207, RK21_04637 and RK21_05539, that had weak homology to the only known cyclohexylamine oxidase (CHAO encoded by chaA) found in Brevibacterium oxydans IH-35A. We also found that a tandem array of five ORFs (RK21_02866-02870) shared homology with those in an operon responsible for oxidation of cyclohexanone to adipic acid, although the ORFs in strain NyZ12 were arranged in a different order with previously found in cyclohexane, cyclohexanol or cyclohexanone degradation strains. The ORFs in this cluster were all up-regulated when CHAM was supplied as the sole carbon source. When one of these five genes, RK21_02867 encoding cyclohexanone (CHnone) monooxygenase, was knocked out, NyZ12 could not grow on CHAM, but it accumulated equimolar amounts of CHnone. Our results show that strain NyZ12 metabolized CHAM directly to CHnone which was then further metabolized to adipate. Despite clearly identifying genes encoding the steps for metabolism of CHAM metabolites, not every one of the putative chaAs was differentially expressed in the presence of CHAM and deletion of each one individually did not completely eliminate the capacity of NyZ12 to degrade CHAM, though it did reduce its growth in several instances. Our results suggest that there is genetic redundancy encoding the initial step in the oxidation of CHAM to CHnone in NyZ12 and that its CHAOs differ considerably from the ChaA, originally described in Brevibacterium oxydans IH-35A.
摘要：
In present study, we showed that the mRNA and protein levels of HO-1 and Hsp70 in solanesol-treated L02 cells were significantly increased. The induction of the HO-1 by solanesol is majorly achieved via enhancing the nuclear translocation and transactivity of Nrf2 through enhancement of Hsp90-Keap1 interaction, while solanesol-elevated Hsp70 is related with promoting the nuclear translocation of HSF1 through the involvement of chaperones interaction. Furthermore, the induction of HO-1 and Hsp70 by solanesol could protect against ethanol-induced liver injury, including significantly suppressing the elevation of the activities of LDH and AST, attenuating ethanol-induced increase of the MDA, ROS level and decrease of the GSH level. Moreover, solanesol also suppressed ethanol-induced apoptosis of L02 cells by inhibition of nuclear morphological damage, procaspase 3 and cleavage of caspase 3 and PARP, suggesting solanesol may be beneficial against ALD. Solanesol also promoted tBHQ-mediated protective effects. However, treatment cells with SnPP or PES markedly abrogated the protective effects of solanesol on ethanol-induced cell injury. These results strongly suggested that solanesol could protect ethanol-induced L02 cell damage, which might be attributed to the activation of HO-1 and Hsp70. (c) 2015 Elsevier Ltd. All rights reserved.
摘要：
A consortium comprised of an engineered Escherichia
coli DH5α and a natural pentachlorophenol (PCP) degrader, Sphingobium
chlorophenolicum ATCC 39723, was assembled for degradation of hexachlorobenzene (HCB), a persistent organic pollutant. The engineered E. coli strain, harbouring a gene cassette (camA
+
camB
+
camC) that encodes the F87W/Y96F/L244A/V247L mutant of cytochrome P-450cam (CYP101), oxidised HCB to PCP. The resulting PCP was then further completely degraded by ATCC 39723. The results showed that almost 40 % of 4 μM HCB was degraded by the consortium at a rate of 0.033 nmol/mg (dry weight)/h over 24 h, accompanied by transient accumulation and immediate consumption of the intermediate PCP, detected by gas chromatography. In contrast, in the consortium comprised of Pseudomonas
putida PaW340 harbouring camA
+
camB
+
camC and ATCC 39723, PCP accumulated in PaW340 cells but could not be further degraded, which may be due to a permeability barrier of Pseudomonas PaW340 for PCP transportation. The strategy of bacterial co-culture may provide an alternative approach for the bioremediation of HCB contamination.
摘要：
Genomic analysis of the catabolic potentialities of Silicibacter pomeroyi DSS-3 against a wide range of natural aromatic compounds and sequence comparisons with the entire genome of this microorganism predicted the existence of at least seven main pathways for the conversion of the aromatic compounds to the intermediates which enter into TCA cycle, that is, the catechol (cat I and cat II genes) and protocatechuate (pca genes) branches of the β-ketoadipate pathway, the phenylacetate pathway (paa genes), the gentisate pathway (gtd genes), the homogentisate pathway (hmg/hppD genes), as well as the homoprotocatechuate pathway (hpc genes). Furthermore, the genes encoding those enzymes involved in the peripheral pathways leading to the β-ketoadipate central pathway were also mapped, i.e., 4-hydroxybenzoate (pob), benzoate (ben), quinate (qui), phenylpropenoid compounds (fcs, ech, vdh, cal, van, acd and act), tyrosine (hpp) and n-phenylalkanoic acids (fad). Evidences showed that S. pomeroyi DSS-3 have versatile abilities to the catabolism of aromatic compounds either in anaerobic or in aerobic pathway, suggesting such a strain might be a model of heuristic value for the study of the genomic organization, the evolution of genes, as well as the catalytic or transcriptional mechanisms of enzymes for aromatic degradation in marine bacteria. Further, it would provide new insights into the biodegradation of aromatic compounds in marine bacteria and marine environments.
