scholarly journals Plasmid-Located Pathogenicity Determinants of Serratia entomophila, the Causal Agent of Amber Disease of Grass Grub, Show Similarity to the Insecticidal Toxins of Photorhabdus luminescens

2000 ◽  
Vol 182 (18) ◽  
pp. 5127-5138 ◽  
Author(s):  
Mark R. H. Hurst ◽  
Travis R. Glare ◽  
Trevor A. Jackson ◽  
Clive W. Ronson

ABSTRACT Serratia entomophila and Serratia proteamaculans cause amber disease in the grass grubCostelytra zealandica (Coleoptera: Scarabaeidae), an important pasture pest in New Zealand. Larval disease symptoms include cessation of feeding, clearance of the gut, amber coloration, and eventual death. A 115-kb plasmid, pADAP, identified in S. entomophila is required for disease causation and, when introduced into Escherichia coli, enables that organism to cause amber disease. A 23-kb fragment of pADAP that conferred disease-causing ability on E. coli and a pADAP-cured strain of S. entomophila was isolated. Using insertion mutagenesis, the pathogenicity determinants were mapped to a 17-kb region of the clone. Sequence analysis of the 17-kb region showed that the predicted products of three of the open reading frames (sepA, sepB, and sepC) showed significant sequence similarity to components of the insecticidal toxin produced by the bacterium Photorhabdus luminescens. Transposon insertions in sepA, sepB, orsepC completely abolished both gut clearance and cessation of feeding on the 23-kb clone; when recombined back into pADAP, they abolished gut clearance but not cessation of feeding. These results suggest that SepA, SepB, and SepC together are sufficient for amber disease causation by S. entomophila and that another locus also able to exert a cessation-of-feeding effect is encoded elsewhere on pADAP.

2000 ◽  
Vol 182 (13) ◽  
pp. 3784-3793 ◽  
Author(s):  
Vincent J. J. Martin ◽  
William W. Mohn

ABSTRACT We have cloned and sequenced the dit gene cluster encoding enzymes of the catabolic pathway for abietane diterpenoid degradation by Pseudomonas abietaniphila BKME-9. Thedit gene cluster is located on a 16.7-kb DNA fragment containing 13 complete open reading frames (ORFs) and 1 partial ORF. The genes ditA1A2A3 encode the α and β subunits and the ferredoxin of the dioxygenase which hydroxylates 7-oxodehydroabietic acid to 7-oxo-11,12-dihydroxy-8,13-abietadien acid. The dioxygenase mutant strain BKME-941 (ditA1::Tn5) did not grow on nonaromatic abietanes, and transformed palustric and abietic acids to 7-oxodehydroabietic acid in cell suspension assays. Thus, nonaromatic abietanes are aromatized prior to further degradation. Catechol 2,3-dioxygenase activity of xylEtranscriptional fusion strains showed induction of ditA1and ditA3 by abietic, dehydroabietic, and 7-oxodehydroabietic acids, which support the growth of strain BKME-9, as well as by isopimaric and 12,14-dichlorodehydroabietic acids, which are diterpenoids that do not support the growth of strain BKME-9. In addition to the aromatic-ring-hydroxylating dioxygenase genes, thedit cluster includes ditC, encoding an extradiol ring cleavage dioxygenase, and ditR, encoding an IclR-type transcriptional regulator. Although ditR is not strictly required for the growth of strain BKME-9 on abietanes, aditR::Kmr mutation in aditA3::xylE reporter strain demonstrated that it encodes an inducer-dependent transcriptional activator of ditA3. An ORF with sequence similarity to genes encoding permeases (ditE) is linked with genes involved in abietane degradation.


2016 ◽  
Vol 4 (4) ◽  
Author(s):  
Leopoldo Palma ◽  
Eleodoro E. Del Valle ◽  
Laureano Frizzo ◽  
Colin Berry ◽  
Primitivo Caballero

Here, we report the draft genome sequence of Photorhabdus luminescens strain DSPV002N, which consists of 177 contig sequences accounting for 5,518,143 bp, with a G+C content of 42.3% and 4,701 predicted protein-coding genes (CDSs). From these, 27 CDSs exhibited significant similarity with insecticidal toxin proteins from Photorhabdus luminescens subsp. laumondii TT01.


2004 ◽  
Vol 70 (11) ◽  
pp. 6587-6594 ◽  
Author(s):  
Susana V�lchez ◽  
Juliette Jacoby ◽  
David J. Ellar

ABSTRACT The successful use of Bacillus thuringiensis insecticidal toxins to control agricultural pests could be undermined by the evolution of insect resistance. Under selection pressure in the laboratory, a number of insects have gained resistance to the toxins, and several cases of resistance in the diamondback moth have been reported from the field. The use of protein engineering to develop novel toxins active against resistant insects could offer a solution to this problem. The display of proteins on the surface of phages has been shown to be a powerful technology to search for proteins with new characteristics from combinatorial libraries. However, this potential of phage display to develop Cry toxins with new binding properties and new target specificities has hitherto not been realized because of the failure of displayed Cry toxins to bind their natural receptors. In this work we describe the construction of a display system in which the Cry1Ac toxin is fused to the amino terminus of the capsid protein D of bacteriophage lambda. The resultant phage was viable and infectious, and the displayed toxin interacted successfully with its natural receptor.


2016 ◽  
Vol 198 (9) ◽  
pp. 1393-1400 ◽  
Author(s):  
Guangyu E. Chen ◽  
Andrew Hitchcock ◽  
Philip J. Jackson ◽  
Roy R. Chaudhuri ◽  
Mark J. Dickman ◽  
...  

ABSTRACTThe major photopigment of the cyanobacteriumAcaryochloris marinais chlorophylld, while its direct biosynthetic precursor, chlorophylla, is also present in the cell. These pigments, along with the majority of chlorophylls utilized by oxygenic phototrophs, carry an ethyl group at the C-8 position of the molecule, having undergone reduction of a vinyl group during biosynthesis. Two unrelated classes of 8-vinyl reductase involved in the biosynthesis of chlorophylls are known to exist, BciA and BciB. The genome ofAcaryochloris marinacontains open reading frames (ORFs) encoding proteins displaying high sequence similarity to BciA or BciB, although they are annotated as genes involved in transcriptional control (nmrA) and methanogenesis (frhB), respectively. These genes were introduced into an 8-vinyl chlorophylla-producing ΔbciBstrain ofSynechocystissp. strain PCC 6803, and both were shown to restore synthesis of the pigment with an ethyl group at C-8, demonstrating their activities as 8-vinyl reductases. We propose thatnmrAandfrhBbe reassigned asbciAandbciB, respectively; transcript and proteomic analysis ofAcaryochloris marinareveal that bothbciAandbciBare expressed and their encoded proteins are present in the cell, possibly in order to ensure that all synthesized chlorophyll pigment carries an ethyl group at C-8. Potential reasons for the presence of two 8-vinyl reductases in this strain, which is unique for cyanobacteria, are discussed.IMPORTANCEThe cyanobacteriumAcaryochloris marinais the best-studied phototrophic organism that uses chlorophylldfor photosynthesis. Unique among cyanobacteria sequenced to date, its genome contains ORFs encoding two unrelated enzymes that catalyze the reduction of the C-8 vinyl group of a precursor molecule to an ethyl group. Carrying a reduced C-8 group may be of particular importance to organisms containing chlorophylld. Plant genomes also contain orthologs of both of these genes; thus, the bacterial progenitor of the chloroplast may also have contained bothbciAandbciB.


2013 ◽  
Vol 57 (6) ◽  
pp. 2603-2612 ◽  
Author(s):  
Narutoshi Uda ◽  
Yasuyuki Matoba ◽  
Takanori Kumagai ◽  
Kosuke Oda ◽  
Masafumi Noda ◽  
...  

ABSTRACTWe have recently cloned a DNA fragment containing a gene cluster that is responsible for the biosynthesis of an antituberculosis antibiotic,d-cycloserine. The gene cluster is composed of 10 open reading frames, designateddcsAtodcsJ. Judging from the sequence similarity between each putative gene product and known proteins, DcsC, which displays high homology to diaminopimelate epimerase, may catalyze the racemization ofO-ureidoserine. DcsD is similar toO-acetylserine sulfhydrylase, which generatesl-cysteine usingO-acetyl-l-serine with sulfide, and therefore, DcsD may be a synthase to generateO-ureido-l-serine usingO-acetyl-l-serine and hydroxyurea. DcsG, which exhibits similarity to a family of enzymes with an ATP-grasp fold, may be an ATP-dependent synthetase convertingO-ureido-d-serine intod-cycloserine. In the present study, to characterize the enzymatic functions of DcsC, DcsD, and DcsG, each protein was overexpressed inEscherichia coliand purified to near homogeneity. The biochemical function of each of the reactions catalyzed by these three proteins was verified by thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and, in some cases, mass spectrometry. The results from this study demonstrate that by using a mixture of the three purified enzymes and the two commercially available substratesO-acetyl-l-serine and hydroxyurea, synthesis ofd-cycloserine was successfully attained. Thesein vitrostudies yield the conclusion that DcsD and DcsG are necessary for the syntheses ofO-ureido-l-serine andd-cycloserine, respectively. DcsD was also able to catalyze the synthesis ofl-cysteine when sulfide was added instead of hydroxyurea. Furthermore, the present study shows that DcsG can also form other cyclicd-amino acid analogs, such asd-homocysteine thiolactone.


2001 ◽  
Vol 67 (2) ◽  
pp. 725-732 ◽  
Author(s):  
Daniela Minerdi ◽  
Renato Fani ◽  
Romina Gallo ◽  
Alessandra Boarino ◽  
Paola Bonfante

ABSTRACT In this paper we report the identification and characterization of a DNA region containing putative nif genes and belonging to a Burkholderia endosymbiont of the arbuscular mycorrhizal fungus Gigaspora margarita. A genomic library of total DNA extracted from the fungal spores was also representative of the bacterial genome and was used to investigate the prokaryotic genome. Screening of the library with Azospirillum brasilense nifHDKgenes as the prokaryotic probes led to the identification of a 6,413-bp region. Analysis revealed three open reading frames encoding putative proteins with a very high degree of sequence similarity with the two subunits (NifD and NifK) of the component I and with component II (NifH) of nitrogenase from different diazotrophs. The three genes were arranged in an operon similar to that shown by most archaeal and bacterial diazotrophs. PCR experiments with primers designed on theBurkholderia nifHDK genes and Southern blot analysis demonstrate that they actually belong to the genome of the G. margarita endosymbiont. They offer, therefore, the first sequence for the nif operon described for Burkholderia. Reverse transcriptase PCR experiments with primers designed on theBurkholderia nifH and nifD genes and performed on total RNA extracted from spores demonstrate that the gene expression was limited to the germination phase. A phylogenetic analysis performed on the available nifK sequences placed the endosymbioticBurkholderia close to A. brasilense.


2018 ◽  
Vol 64 (7) ◽  
pp. 483-491 ◽  
Author(s):  
Urmi Bajpai ◽  
Abhishek Kumar Mehta ◽  
Kandasamy Eniyan ◽  
Avni Sinha ◽  
Ankita Ray ◽  
...  

Bacteriophages are being considered as a promising natural resource for the development of alternative strategies against mycobacterial diseases, especially in the context of the wide-spread occurrence of drug resistance among the clinical isolates of Mycobacterium tuberculosis. However, there is not much information documented on mycobacteriophages from India. Here, we report the isolation of 17 mycobacteriophages using Mycobacterium smegmatis as the bacterial host, where 9 phages also lyse M. tuberculosis H37Rv. We present detailed analysis of one of these mycobacteriophages — PDRPv. Transmission electron microscopy and polymerase chain reaction analysis (of a conserved region within the TMP gene) show PDRPv to belong to the Siphoviridae family and B1 subcluster, respectively. The genome (69 110 bp) of PDRPv is circularly permuted double-stranded DNA with ∼66% GC content and has 106 open reading frames (ORFs). On the basis of sequence similarity and conserved domains, we have assigned function to 28 ORFs and have broadly categorized them into 6 groups that are related to replication and genome maintenance, DNA packaging, virion release, structural proteins, lysogeny-related genes and endolysins. The present study reports the occurrence of novel antimycobacterial phages in India and highlights their potential to contribute to our understanding of these phages and their gene products as potential antimicrobial agents.


2000 ◽  
Vol 182 (21) ◽  
pp. 6066-6074 ◽  
Author(s):  
Andrew M. Kropinski

ABSTRACT Temperate bacteriophage D3, a member of the virus familySiphoviridae, is responsible for serotype conversion in its host, Pseudomonas aeruginosa. The complete sequence of the double-stranded DNA genome has been determined. The 56,426 bp contains 90 putative open reading frames (ORFs) and four genes specifying tRNAs. The latter are specific for methionine (AUG), glycine (GGA), asparagine (AAC), and threonine (ACA). The tRNAs may function in the translation of certain highly expressed proteins from this relatively AT-rich genome. D3 proteins which exhibited a high degree of sequence similarity to previously characterized phage proteins included the portal, major head, tail, and tail tape measure proteins, endolysin, integrase, helicase, and NinG. The layout of genes was reminiscent of lambdoid phages, with the exception of the placement of the endolysin gene, which parenthetically also lacked a cognate holin. The greatest sequence similarity was found in the morphogenesis genes to coliphages HK022 and HK97. Among the ORFs was discovered the gene encoding the fucosamine O-acetylase, which is in part responsible for the serotype conversion events.


2007 ◽  
Vol 189 (23) ◽  
pp. 8727-8736 ◽  
Author(s):  
David E. Greenberg ◽  
Stephen F. Porcella ◽  
Adrian M. Zelazny ◽  
Kimmo Virtaneva ◽  
Dan E. Sturdevant ◽  
...  

ABSTRACT Chronic granulomatous disease (CGD) is an inherited immune deficiency characterized by increased susceptibility to infection with Staphylococcus, certain gram-negative bacteria, and fungi. Granulibacter bethesdensis, a newly described genus and species within the family Acetobacteraceae, was recently isolated from four CGD patients residing in geographically distinct locales who presented with fever and lymphadenitis. We sequenced the genome of the reference strain of Granulibacter bethesdensis, which was isolated from lymph nodes of the original patient. The genome contains 2,708,355 base pairs in a single circular chromosome, in which 2,437 putative open reading frames (ORFs) were identified, 1,470 of which share sequence similarity with ORFs in the nonpathogenic but related Gluconobacter oxydans genome. Included in the 967 ORFs that are unique to G. bethesdensis are ORFs potentially important for virulence, adherence, DNA uptake, and methanol utilization. GC% values and best BLAST analysis suggested that some of these unique ORFs were recently acquired. Comparison of G. bethesdensis to other known CGD pathogens demonstrated conservation of some putative virulence factors, suggesting possible common mechanisms involved in pathogenesis in CGD. Genotyping of the four patient isolates by use of a custom microarray demonstrated genome-wide variations in regions encoding DNA uptake systems and transcriptional regulators and in hypothetical ORFs. G. bethesdensis is a genetically diverse emerging human pathogen that may have recently acquired virulence factors new to this family of organisms.


2002 ◽  
Vol 184 (12) ◽  
pp. 3194-3202 ◽  
Author(s):  
Takahiro Murata ◽  
Makoto Ohnishi ◽  
Takeshi Ara ◽  
Jun Kaneko ◽  
Chang-Gyun Han ◽  
...  

ABSTRACT Rts1, a large conjugative plasmid originally isolated from Proteus vulgaris, is a prototype for the IncT plasmids and exhibits pleiotropic thermosensitive phenotypes. Here we report the complete nucleotide sequence of Rts1. The genome is 217,182 bp in length and contains 300 potential open reading frames (ORFs). Among these, the products of 141 ORFs, including 9 previously identified genes, displayed significant sequence similarity to known proteins. The set of genes responsible for the conjugation function of Rts1 has been identified. A broad array of genes related to diverse processes of DNA metabolism were also identified. Of particular interest was the presence of tus-like genes that could be involved in replication termination. Inspection of the overall genome organization revealed that the Rts1 genome is composed of four large modules, providing an example of modular evolution of plasmid genomes.


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