NGHIÊN CỨU SỬ DỤNG MÀNG BAO SINH HỌC TỪ DỊCH CHIẾT VI KHUẨN Pseudomonas putida 199B ĐẾN KHÁNG NẤM Aspergilus flavus T1 TRONG QUÁ TRÌNH BẢO QUẢN HẠT GIỐNG NGÔ

2017 ◽  
Vol 126 (3C) ◽  
Author(s):  
Nguyễn Thỵ Đan Huyền ◽  
Lê Thanh Long ◽  
Trần Thị Thu Hà ◽  
Nguyễn Cao Cường ◽  
Nguyễn Hiền Trang
Keyword(s):  
Pseudomonas Putida ◽  
28S Rrna

Chủng T1 phân lập từ các mẫu ngô nếp NK66 nhiễm nấm mốc tự nhiên được sử dụng để nghiên cứu khả năng kháng nấm của dịch chiết vi khuẩn Pseudomonas putida 199B. Đặc điểm hình thái của chủng T1 đã được quan sát đại thể (màu sắc, hình dáng, kích thước khuẩn lạc) trên môi trường PDA và vi thể (hình dáng bào tử) trên kính hiển vi kết hợp so sánh với loài Aspergilus flavus đối chứng. Kết quả phân tích trình tự gen mã hóa 28S rRNA của chủng T1 cho thấy sự tương đồng trình tự cao với các trình tự tương ứng của loài Aspergilus flavus trên ngân hàng gen. Kết quả khảo sát ảnh hưởng của dịch chiết vi khuẩn P. putida lên sự phát triển của nấm A.  flavus gây bệnh trên hạt ngô sau thu hoạch và bảo quản ở điều kiện in vitro cho thấy, ở nồng độ P. putida 24% đã ức chế 74,50% sự phát triển đường kính tản nấm sau 10 ngày nuôi cấy, ức chế 79,63% sự hình thành sinh khối sợi nấm sau 7 ngày nuôi cấy. Ở điều kiện in vivo, sự nảy mầm của hạt giống ngô sau 30 ngày được tạo màng bao sinh học bằng dịch chiết vi khuẩn P. putida nồng độ 18% đạt 97,91%, tỉ lệ hạt nhiễm nấm mốc giảm còn 20% so với 72% ở mẫu đối chứng.

In Vitro and In Vivo Interactions of Ferredoxin-NADP+ Reductases in Pseudomonas putida

2009 ◽  
Vol 145 (4) ◽  
pp. 481-491 ◽  
Author(s):  
Jinki Yeom ◽  
Che Ok Jeon ◽  
Eugene L. Madsen ◽  
Woojun Park
Keyword(s):  
Pseudomonas Putida

scholarly journals In Vivo and In Vitro Evidence that TtgV Is the Specific Regulator of the TtgGHI Multidrug and Solvent Efflux Pump of Pseudomonas putida

2003 ◽  
Vol 185 (16) ◽  
pp. 4755-4763 ◽  
Author(s):  
Antonia Rojas ◽  
Ana Segura ◽  
María Eugenia Guazzaroni ◽  
Wilson Terán ◽  
Ana Hurtado ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Aromatic Hydrocarbons ◽  
Efflux Pump ◽  
Mobility Shift ◽  
Regulation Of Expression ◽  
High Affinity ◽  
Induced Tolerance ◽  
Background Expression

ABSTRACT The TtgGHI efflux pump of Pseudomonas putida DOT-T1E plays a key role in the innate and induced tolerance of this strain to aromatic hydrocarbons and antibiotics. The ttgGHI operon is expressed constitutively from two overlapping promoters in the absence of solvents and at a higher level in their presence, but not in response to antibiotics. Adjacent to the ttgGHI operon is the divergently transcribed ttgVW operon. In TtgV-deficient backgrounds, although not in a TtgW-deficient background, expression of the ttgGHI and ttgVW operons increased fourfold. This suggests that TtgV represses expression from the ttgG promoters and controls its own. TtgW plays no major role in the regulation of expression of these promoters. Primer extension revealed that the divergent ttgG and ttgV promoters overlap, and mobility shift assays indicated that TtgV binds to this region with high affinity. DNaseI footprint assays revealed that TtgV protected four DNA helical turns that include the −10 and −35 boxes of the ttgV and ttgG promoters.

scholarly journals A DNA Vaccine Encoding the Enterohemorragic Escherichia coli Shiga-Like Toxin 2 A2 and B Subunits Confers Protective Immunity to Shiga Toxin Challenge in the Murine Model

2009 ◽  
Vol 16 (5) ◽  
pp. 712-718 ◽  
Author(s):  
Leticia V. Bentancor ◽  
Marcos Bilen ◽  
Romina J. Fernández Brando ◽  
María Victoria Ramos ◽  
Luis C. S. Ferreira ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Vaccine ◽  
Protective Immunity ◽  
Host Cells ◽  
Therapeutic Interventions ◽  
28S Rrna ◽  
A Subunit ◽  
B Subunits

ABSTRACT Production of verocytotoxin or Shiga-like toxin (Stx), particularly Stx2, is the basis of hemolytic uremic syndrome, a frequently lethal outcome for subjects infected with Stx2-producing enterohemorrhagic Escherichia coli (EHEC) strains. The toxin is formed by a single A subunit, which promotes protein synthesis inhibition in eukaryotic cells, and five B subunits, which bind to globotriaosylceramide at the surface of host cells. Host enzymes cleave the A subunit into the A1 peptide, endowed with N-glycosidase activity to the 28S rRNA, and the A2 peptide, which confers stability to the B pentamer. We report the construction of a DNA vaccine (pStx2ΔAB) that expresses a nontoxic Stx2 mutated form consisting of the last 32 amino acids of the A2 sequence and the complete B subunit as two nonfused polypeptides. Immunization trials carried out with the DNA vaccine in BALB/c mice, alone or in combination with another DNA vaccine encoding granulocyte-macrophage colony-stimulating factor, resulted in systemic Stx-specific antibody responses targeting both A and B subunits of the native Stx2. Moreover, anti-Stx2 antibodies raised in mice immunized with pStx2ΔAB showed toxin neutralization activity in vitro and, more importantly, conferred partial protection to Stx2 challenge in vivo. The present vector represents the second DNA vaccine so far reported to induce protective immunity to Stx2 and may contribute, either alone or in combination with other procedures, to the development of prophylactic or therapeutic interventions aiming to ameliorate EHEC infection-associated sequelae.

Processing of truncated mouse or human rRNA transcribed from ribosomal minigenes transfected into mouse cells

1994 ◽  
Vol 14 (6) ◽  
pp. 4044-4056
Author(s):  
K V Hadjiolova ◽  
A Normann ◽  
J Cavaillé ◽  
E Soupène ◽  
S Mazan ◽  
...  
Keyword(s):  
18S Rrna ◽  
Processing System ◽  
Rrna Genes ◽  
In Vitro Assays ◽  
Rrna Gene ◽  
28S Rrna ◽  
Rrna Processing ◽  
Mouse Cells

The processing of pre-rRNA in eukaryotic cells involves a complex pattern of nucleolytic reactions taking place in preribosomes with the participation of several nonribosomal proteins and small nuclear RNAs. The mechanism of these reactions remains largely unknown, mainly because of the absence of faithful in vitro assays for most processing steps. We have developed a pre-rRNA processing system using the transient expression of ribosomal minigenes transfected into cultured mouse cells. Truncated mouse or human rRNA genes are faithfully transcribed under the control of mouse promoter and terminator signals. The fate of these transcripts is analyzed by the use of reporter sequences flanking the rRNA gene inserts. Both mouse and human transcripts, containing the 3' end of 18S rRNA-encoding DNA (rDNA), internal transcribed spacer (ITS) 1, 5.8S rDNA, ITS 2, and the 5' end of 28S rDNA, are processed predominantly to molecules coterminal with the natural mature rRNAs plus minor products corresponding to cleavages within ITS 1 and ITS 2. To delineate cis-acting signals in pre-rRNA processing, we studied series of more truncated human-mouse minigenes. A faithful processing at the 18S rRNA/ITS 1 junction can be observed with transcripts containing only the 60 3'-terminal nucleotides of 18S rRNA and the 533 proximal nucleotides of ITS 1. However, further truncation of 18S rRNA (to 8 nucleotides) or of ITS 1 (to 48 nucleotides) abolishes the cleavage of the transcript. Processing at the ITS 2/28S rRNA junction is observed with truncated transcripts lacking the 5.8S rRNA plus a major part of ITS 2 and containing only 502 nucleotides of 28S rRNA. However, further truncation of the 28S rRNA segment to 217 nucleotides abolishes processing. Minigene transcripts containing most internal sequences of either ITS 1 or ITS 2, but devoid of ITS/mature rRNA junctions, are not processed, suggesting that the cleavages in vivo within either ITS segment are dependent on the presence in cis of mature rRNA sequences. These results show that the major cis signals for pre-rRNA processing at the 18S rRNA/ITS 1 or the ITS2/28S rRNA junction involve solely a limited critical length of the respective mature rRNA and adjacent spacer sequences.

scholarly journals Analysis of Pseudomonas putida KT2440 Gene Expression in the Maize Rhizosphere: In Vitro Expression Technology Capture and Identification of Root-Activated Promoters

2005 ◽  
Vol 187 (12) ◽  
pp. 4033-4041 ◽  
Author(s):  
María Isabel Ramos-González ◽  
María Jesús Campos ◽  
Juan L. Ramos
Keyword(s):  
Pseudomonas Putida ◽  
Defense Mechanism ◽  
Essential Gene ◽  
Cell Envelope ◽  
Original Position ◽  
Pseudomonas Putida Kt2440 ◽  
Maize Rhizosphere ◽  
Semialdehyde Dehydrogenase

ABSTRACT Pseudomonas putida KT2440, a paradigm organism in biodegradation and a good competitive colonizer of the maize rhizosphere, was the subject of studies undertaken to establish the genetic determinants important for its rhizospheric lifestyle. By using in vivo expression technology (IVET) to positively select single cell survival, we identified 28 rap genes (root-activated promoters) preferentially expressed in the maize rhizosphere. The IVET system had two components: a mutant affected in aspartate-β-semialdehyde dehydrogenase (asd), which was unable to survive in the rhizosphere, and plasmid pOR1, which carries a promoterless asd gene. pOR1-borne transcriptional fusions of the rap promoters to the essential gene asd, which were integrated into the chromosome at the original position of the corresponding rap gene, were active and allowed growth of the asd strain in the rhizosphere. The fact that five of the rap genes identified in the course of this work had been formerly characterized as being related to root colonization reinforced the IVET approach. Up to nine rap genes encoded proteins either of unknown function or that had been assigned an unspecific role based on conservation of the protein family domains. Rhizosphere-induced fusions included genes with probable functions in the cell envelope, chemotaxis and motility, transport, secretion, DNA metabolism and defense mechanism, regulation, energy metabolism, stress, detoxification, and protein synthesis.

scholarly journals Outer membrane vesicles catabolize lignin-derived aromatic compounds in Pseudomonas putida KT2440

2020 ◽  
Vol 117 (17) ◽  
pp. 9302-9310 ◽  
Author(s):  
Davinia Salvachúa ◽  
Allison Z. Werner ◽  
Isabel Pardo ◽  
Martyna Michalska ◽  
Brenna A. Black ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Outer Membrane ◽  
Aromatic Compounds ◽  
Value Added ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Pseudomonas Putida Kt2440 ◽  
Rich Media

Lignin is an abundant and recalcitrant component of plant cell walls. While lignin degradation in nature is typically attributed to fungi, growing evidence suggests that bacteria also catabolize this complex biopolymer. However, the spatiotemporal mechanisms for lignin catabolism remain unclear. Improved understanding of this biological process would aid in our collective knowledge of both carbon cycling and microbial strategies to valorize lignin to value-added compounds. Here, we examine lignin modifications and the exoproteome of three aromatic–catabolic bacteria: Pseudomonas putida KT2440, Rhodoccocus jostii RHA1, and Amycolatopsis sp. ATCC 39116. P. putida cultivation in lignin-rich media is characterized by an abundant exoproteome that is dynamically and selectively packaged into outer membrane vesicles (OMVs). Interestingly, many enzymes known to exhibit activity toward lignin-derived aromatic compounds are enriched in OMVs from early to late stationary phase, corresponding to the shift from bioavailable carbon to oligomeric lignin as a carbon source. In vivo and in vitro experiments demonstrate that enzymes contained in the OMVs are active and catabolize aromatic compounds. Taken together, this work supports OMV-mediated catabolism of lignin-derived aromatic compounds as an extracellular strategy for nutrient acquisition by soil bacteria and suggests that OMVs could potentially be useful tools for synthetic biology and biotechnological applications.

scholarly journals Study on the In vitro and In vivo Antifungal Activities of Nano-silver against Mycoleptodiscus indicus causing Leaf Blight on Lotus in Vietnam

2021 ◽  
Author(s):  
Hoang Thi Kim Hong ◽  
Nguyen Quang Hoang Vu ◽  
Nguyen Thi Ngoc Hanh ◽  
Tran Thi Ha ◽  
Le Quang Tien Dung
Keyword(s):  
Pathogenic Fungi ◽  
Leaf Blight ◽  
28S Rrna ◽  
Minimal Inhibition Concentration ◽  
Nano Silver ◽  
Inhibition Concentration ◽  
Rrna Sequencing ◽  
Lotus Leaves

Background: Lotus, Nelumbo nucifera Gaertn is Vietnam’s symbol and Buddhism’s flower and plays an essential part in rural Vietnam’s economy as all aspects of lotus could bring benefits to farmers. But, unfortunately, lotus yield in Vietnam is seriously affected by various plant diseases. Among them, leaf blight is currently emerging as one of the primary diseases devastating lotus crops in Vietnam, in which there are large necrotic parts on lotus leaves, flowers and seeds. Methods: Aloe barbadensis extract was used for synthesizing silver nanoparticles. Leaf blight lotus leaves were collected to isolate pathogenic fungi-infection of isolated pathogenic fungi on the healthy lotus and then identify hidden mold by 28S rRNA sequencing. Determination of in vitro minimal inhibition concentration of nano-silver was conducted according to Azizi. The reduction of disease symptoms and biological characteristics of the treated lotus was observed. Result: Morphological analysis and molecular identification of 28S rRNA sequencing showed that the pathogenic microorganism was Mycoleptodiscus indicus (M. indicus). Both in vitro antifungal activity and in vivo treatment of leaf blight lotus using a nano-silver solution showed that 30 ppm of nano-silver was the minimal inhibition concentration (MIC) for totally eradicating M. indicus growth. This was the first time M. indicus was reported to infect and cause leaf blight on a lotus. Previously, M. indicus was a well-known plant pathogen that could cross-kingdom infect humans and animals. Thus, the fact that lotus is widely cultured in Vietnamese rural could increase the chance for M. indicus to spread; hence, this raised the alarm about its potential harm to plants, humans and animals. And, significantly, it revealed nano-silver as a possible approach to prevent M. indicus.

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