scholarly journals Molecular Cloning, Sequencing, Expression, and Characterization of an Immunogenic 43-Kilodalton Lipoprotein of Bartonella bacilliformis That Has Homology to NlpD/LppB

2000 ◽  
Vol 68 (9) ◽  
pp. 4972-4979 ◽  
Author(s):  
Indira Padmalayam ◽  
Timothy Kelly ◽  
Barbara Baumstark ◽  
Robert Massung
Keyword(s):  
Bartonella Henselae ◽  
High Titer ◽  
Polyclonal Antiserum ◽  
Open Reading Frame ◽  
Bartonella Bacilliformis ◽  
Reading Frame ◽  
Dna Library ◽  
Bacillary Angiomatosis ◽  
Genomic Dna Library ◽  
Entire Open Reading Frame

ABSTRACT A recombinant clone expressing an immunoreactive antigen ofBartonella bacilliformis was isolated by screening a genomic DNA library with serum from a patient with the chronic verruga phase of bartonellosis. The clone, pBIPIM-17, contained a partial open reading frame that expressed an immunoreactive fusion protein. Subsequent rescreening of the library by plaque hybridization resulted in the isolation of recombinant clones that contain the entire open reading frame. The open reading frame (ORF-401) is capable of encoding a protein of 401 amino acids with a predicted molecular mass of 43 kDa. The deduced amino acid sequence of the encoded protein was found to be highly homologous to a recently identified bacterial lipoprotein (LppB/NlpD) which has been associated with virulence. Evidence has been provided to show that the 43-kDa antigen of B. bacilliformis is a lipoprotein and that it is likely to use the same biosynthetic pathway as other bacterial lipoproteins. This is the first report to date that characterizes a lipoprotein of B. bacilliformis. The immunogenicity of the B. bacilliformis LppB homologue was demonstrated by Western blot analysis using sera from patients with clinical bartonellosis. Sera from patients who had a high titer forBartonella henselae, the causative agent of bacillary angiomatosis and cat scratch disease, also recognized the recombinant 43-kDa antigen, suggesting that a homologue of this antigen is present in B. henselae. Using a cocktail of synthetic peptides corresponding to predicted major antigenic sites, polyclonal antiserum specific for the LppB homologue of B. bacilliformis was generated. This antiserum did not recognize the NlpD homologue of Escherichia coli or the 43-kDa antigen ofB. henselae.

scholarly journals Isolation and characterization of PEP5, a gene essential for vacuolar biogenesis in Saccharomyces cerevisiae.

Genetics ◽  
1990 ◽  
Vol 125 (4) ◽  
pp. 739-752 ◽  
Author(s):  
C A Woolford ◽  
C K Dixon ◽  
M F Manolson ◽  
R Wright ◽  
E W Jones
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Mass ◽  
Open Reading Frame ◽  
Relative Molecular Mass ◽  
Cell Fractionation ◽  
Calculated Molecular Mass ◽  
Reading Frame ◽  
Dna Library ◽  
Isolation And Characterization ◽  
Genomic Dna Library

Abstract pep5 mutants of Saccharomyces cerevisiae accumulate inactive precursors to the vacuolar hydrolases. The PEP5 gene was isolated from a genomic DNA library by complementation of the pep5-8 mutation. Deletion analysis localized the complementing activity to a 3.3-kb DNA fragment. DNA sequence analysis of the PEP5 gene revealed an open reading frame of 1029 codons with a calculated molecular mass for the encoded protein of 117,403 D. Deletion/disruption of the PEP5 gene did not kill the cells. The resulting strains grow very slowly at 37 degrees. The disruption mutant showed greatly decreased activities of all vacuolar hydrolases examined, including PrA, PrB, CpY, and the repressible alkaline phosphatase. Apparently normal precursors forms of the proteases accumulated in pep5 mutants, as did novel forms of PrB antigen. Antibodies raised to a fusion protein that contained almost half of the PEP5 open reading frame allowed detection by immunoblot of a protein of relative molecular mass 107 kD in extracts prepared from wild-type cells. Cell fractionation showed the PEP5 gene product is enriched in the vacuolar fraction and appears to be a peripheral vacuolar membrane protein.

scholarly journals Freshwater Bacteria Can Methylate Selenium through the Thiopurine Methyltransferase Pathway

2003 ◽  
Vol 69 (7) ◽  
pp. 3784-3790 ◽  
Author(s):  
Lionel Ranjard ◽  
Sylvie Nazaret ◽  
Benoit Cournoyer
Keyword(s):  
Pseudomonas Syringae ◽  
Sodium Selenite ◽  
Blot Hybridization ◽  
Sodium Selenate ◽  
Thiopurine Methyltransferase ◽  
Freshwater Environment ◽  
Reading Frame ◽  
Dna Library ◽  
Freshwater Bacteria ◽  
Genomic Dna Library

ABSTRACT Involvement of the bacterial thiopurine methyltransferase (bTPMT) in natural selenium methylation by freshwater was investigated. A freshwater environment that had no known selenium contamination but exhibited reproducible emission of dimethyl selenide (DMSe) or dimethyl diselenide (DMDSe) when it was supplemented with an organic form of selenium [(methyl)selenocysteine] or an inorganic form of selenium (sodium selenite) was used. The distribution of the bTPMT gene (tpm) in the microflora was studied. Freshwater bacteria growing on 10 μM sodium selenite and 10 μM sodium selenate were isolated, and 4.5 and 10% of the strains, respectively, were shown by colony blot hybridization to hybridize with a Pseudomonas syringae tpm DNA probe. Ribotyping showed that these strains are closely related. The complete rrs sequence of one of the strains, designated Hsa.28, was obtained and analyzed. Its closest phyletic neighbor was found to be the Pseudomonas anguilliseptica rrs sequence. The Hsa.28 strain grown with sodium selenite or (methyl)selenocysteine produced significant amounts of DMSe and DMDSe. The Hsa.28 tpm gene was isolated by genomic DNA library screening and sequencing. BLASTP comparisons of the deduced Hsa.28 bTPMT sequence with P. syringae, Pseudomonas aeruginosa, Vibrio cholerae, rat, and human thiopurine methyltransferase sequences revealed that the levels of similarity were 52 to 71%. PCR-generated Escherichia coli subclones containing the Hsa.28 tpm open reading frame were constructed. E. coli cells harboring the constructs and grown with sodium selenite or (methyl)selenocysteine produced significant levels of DMSe and DMDSe, confirming that the gene plays a role in selenium methylation. The effect of strain Hsa.28 population levels on freshwater DMSe and DMDSe emission was investigated. An increase in the size of the Hsa.28 population was found to enhance significantly the emission of methyl selenides by freshwater samples supplemented with sodium selenite or (methyl)selenocysteine. These data suggest that bTPMT can play a role in natural freshwater selenium methylation processes.

scholarly journals The genes YNI1 and YNR1, encoding nitrite reductase and nitrate reductase respectively in the yeast Hansenula polymorpha, are clustered and co-ordinately regulated

1996 ◽  
Vol 317 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Nélida BRITO ◽  
Julio AVILA ◽  
M. Dolores PEREZ ◽  
Celedonio GONZALEZ ◽  
José M. SIVERIO
Keyword(s):  
Nitrate Reductase ◽  
Nitrite Reductase ◽  
Reductase Activity ◽  
Hansenula Polymorpha ◽  
Enzymic Activity ◽  
Wild Type ◽  
Reading Frame ◽  
Dna Library ◽  
Genomic Dna Library ◽  
Nitrate And Nitrite

The nitrite reductase-encoding gene (YNI1) from the yeast Hansenula polymorpha was isolated from a lambda EMBL3 H. polymorpha genomic DNA library, using as a probe a 481 bp DNA fragment from the gene of Aspergillus nidulans encoding nitrite reductase (niiA). An open reading frame of 3132 bp, encoding a putative protein of 1044 amino acids with high similarity with nitrite reductases from fungi, was located by DNA sequencing in the phages λNB5 and λJA13. Genes YNI1 and YNR1 (encoding nitrate reductase) are clustered, separated by 1700 bp. Northern blot analysis showed that expression of YNI1 and YNR1 is co-ordinately regulated; induced by nitrate and nitrite and repressed by sources of reduced nitrogen, even in the presence of nitrate. A mutant lacking nitrite reductase activity was obtained by deletion of the chromosomal copy of YNI1. The mutant does not grow in nitrate or in nitrite; it exhibits a similar level of transcription of YNR1 to the wild type, but the nitrate reductase enzymic activity is only about 50% of the wild type. In the presence of nitrate the Δyni1::URA3 mutant extrudes approx. 24 nmol of nitrite/h per mg of yeast (wet weight), about five times more than the wild type.

scholarly journals Regulation of an Osmoticum-Responsive Gene in Anabaena sp. Strain PCC 7120

1998 ◽  
Vol 180 (23) ◽  
pp. 6332-6337 ◽  
Author(s):  
Steven H. Schwartz ◽  
Todd A. Black ◽  
Karin Jäger ◽  
Jean-Michel Panoff ◽  
C. Peter Wolk
Keyword(s):  
Genomic Sequence ◽  
Response Regulator ◽  
Sequence Similarity ◽  
Open Reading Frame ◽  
Response Regulators ◽  
Reading Frame ◽  
Regulatory Systems ◽  
Entire Open Reading Frame ◽  
Anabaena Sp ◽  
Pcc 7120

ABSTRACT Salt-induced genes in the cyanobacterium Anabaena sp. strain PCC 7120 were identified by use of a Tn5-based transposon bearing luxAB as a reporter. The genomic sequence adjacent to one site of insertion of the transposon was identical in part to the sequence of thelti2 gene, which was previously identified in a differential screen for cold-induced transcripts in Anabaena variabilis. The lti2-like gene was induced by sucrose and other osmotica and by low temperature, in addition to salt. Regulatory components necessary for the induction of this gene by osmotica were sought by a further round of transposon mutagenesis. One mutant that displayed reduced transcriptional activity of thelti2-like gene in response to exposure to osmotica had an insertion in an open reading frame, which was denoted orrA, whose predicted product showed sequence similarity to response regulators from two-component regulatory systems. The corresponding mutation was reconstructed and was shown, like the second-site transposon mutation, to result in reduced response to osmotic stress. Induction of the lux reporter gene by osmotica was restored by complementation with a genomic fragment containing the entire open reading frame for the presumptive response regulator, whereas a fragment containing a truncated copy of the open reading frame for the response regulator did not complement the mutation.

scholarly journals Recombinant GRA4 or ROP2 Protein Combined with Alum or the gra4 Gene Provides Partial Protection in Chronic Murine Models of Toxoplasmosis

2004 ◽  
Vol 11 (4) ◽  
pp. 704-710 ◽  
Author(s):  
Valentina Martin ◽  
Alicia Supanitsky ◽  
Pablo C. Echeverria ◽  
Silvana Litwin ◽  
Tamara Tanos ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Open Reading Frame ◽  
Interleukin 4 ◽  
Murine Models ◽  
Protective Level ◽  
Partial Protection ◽  
Reading Frame ◽  
C3h Mice ◽  
Entire Open Reading Frame ◽  
Brain Cysts

ABSTRACT The efficacy of vaccination with Toxoplasma gondii recombinant GRA4 (rGRA4) and ROP2 (rRPO2) proteins and a mix of both combined with alum were evaluated in C57BL/6 and C3H mice. In C57BL/6 mice, rGRA4 and rGRA4-rROP2 immunizations generated similar levels of immunoglobulin G1 (IgG1) and IgG2a isotypes against GRA4, whereas immunizations with rROP2 and the mix induced a predominant IgG1 production against ROP2. All groups of C3H vaccinated mice exhibited higher levels of IgG1 than IgG2a. rGRA4-stimulated splenocytes from vaccinated mice produced primarily gamma interferon while those stimulated with rROP2 produced interleukin-4. Challenge of rGRA4- or rGRA4-rROP2-vaccinated mice from both strains with ME49 cysts resulted in fewer brain cysts than the controls, whereas vaccination with rROP2 alone only conferred protection to C3H mice. Immunization with a plasmid carrying the entire open reading frame of GRA4 showed a protective level similar to that of rGRA4 combined with alum. These results suggest that GRA4 can be a good candidate for a multiantigen anti-T. gondii vaccine based on the use of alum as an adjuvant.

scholarly journals Low-Temperature Lipase from Psychrotrophic Pseudomonas sp. Strain KB700A

2001 ◽  
Vol 67 (9) ◽  
pp. 4064-4069 ◽  
Author(s):  
Naeem Rashid ◽  
Yuji Shimada ◽  
Satoshi Ezaki ◽  
Haruyuki Atomi ◽  
Tadayuki Imanaka
Keyword(s):  
Lipase Activity ◽  
Lipase Gene ◽  
Reading Frame ◽  
Cold Environments ◽  
Dna Library ◽  
Gene Sequence Analysis ◽  
Genomic Dna Library ◽  
Lipase A ◽  
Chain Lengths ◽  
Sigmoidal Growth

ABSTRACT We have previously reported that a psychrotrophic bacterium,Pseudomonas sp. strain KB700A, which displays sigmoidal growth even at −5°C, produced a lipase. A genomic DNA library of strain KB700A was introduced into Escherichia coli TG1, and screening on tributyrin-containing agar plates led to the isolation of the lipase gene. Sequence analysis revealed an open reading frame (KB-lip) consisting of 1,422 nucleotides that encoded a protein (KB-Lip) of 474 amino acids with a molecular mass of 49,924 Da. KB-Lip showed 90% identity with the lipase fromPseudomonas fluorescens and was found to be a member of Subfamily I.3 lipase. Gene expression and purification of the recombinant protein were performed. KB-Lip displayed high lipase activity in the presence of Ca2+. Addition of EDTA completely abolished lipase activity, indicating that KB-Lip was a Ca2+-dependent lipase. Addition of Mn2+ and Sr2+ also led to enhancement of lipase activity but to a much lower extent than that produced by Ca2+. The optimal pH of KB-Lip was 8 to 8.5. The addition of detergents enhanced the enzyme activity. When p-nitrophenyl esters and triglyceride substrates of various chain-lengths were examined, the lipase displayed highest activity towards C10 acyl groups. We also determined the positional specificity and found that the activity was 20-fold higher toward the 1(3) position than toward the 2 position. The optimal temperature for KB-Lip was 35°C, lower than that for any previously reported Subfamily I.3 lipase. The enzyme was also thermolabile compared to these lipases. Furthermore, KB-Lip displayed higher levels of activity at low temperatures than did other enzymes from Subfamily I.3, indicating that KB-Lip has evolved to function in cold environments, in accordance with the temperature range for growth of its psychrotrophic host, strain KB700A.

Cloning and analysis of the aroB gene encoding dehydroquinate synthase from Corynebacterium glutamicum

1999 ◽  
Vol 45 (10) ◽  
pp. 885-890 ◽  
Author(s):  
Min-Ah Han ◽  
Heung-Shick Lee ◽  
Choong-Ill Cheon ◽  
Kyung-Hee Min ◽  
Myeong-Sok Lee
Keyword(s):  
Escherichia Coli ◽  
Corynebacterium Glutamicum ◽  
Auxotrophic Mutant ◽  
Gene Products ◽  
Gene Encoding ◽  
Reading Frame ◽  
E Coli ◽  
Dna Library ◽  
Genomic Dna Library ◽  
Dehydroquinate Synthase

The aroB gene encoding dehydroquinate synthase of Corynebacterium glutamicum has been cloned by complementation of an aro auxotrophic mutant of Escherichia coli with the genomic DNA library. The recombinant plasmid contained a 1.4-kb fragment that complemented the Escherichia coli dehydroquinate-synthase-deficient mutant. The nucleotide sequences of the subcloned DNA has been determined. The sequences contain an open reading frame of 360 codons, from which a protein with a molecular mass of about 38 kDa could be predicted. This is consistent with the size of the AroB protein expressed in E. coli. Alignment of different prokaryotic and eukaryotic aroB gene products reveals an overall identity ranging from 29 to 57% and the presence of several highly conserved regions.Key words: Corynebacterium glutamicum, aromatic amino acid biosynthetic gene, dehydroquinate synthase, aroB gene.

scholarly journals Cloning and Characterization of the Lipooligosaccharide Galactosyltransferase II Gene ofHaemophilus ducreyi

2000 ◽  
Vol 182 (8) ◽  
pp. 2292-2298 ◽  
Author(s):  
Shuhua Sun ◽  
Birgit Schilling ◽  
Laurie Tarantino ◽  
Michael V. Tullius ◽  
Bradford W. Gibson ◽  
...  
Keyword(s):  
Sodium Dodecyl ◽  
Etiologic Agent ◽  
Pasteurella Haemolytica ◽  
Published Data ◽  
Reading Frame ◽  
Ulcer Disease ◽  
Dna Library ◽  
Binding Epitope ◽  
Galactose Residue ◽  
Genomic Dna Library

ABSTRACT Haemophilus ducreyi is the etiologic agent of chancroid, a genital ulcer disease. The lipooligosaccharide (LOS) is considered to be a major virulence determinant and has been implicated in the adherence of H. ducreyi to keratinocytes. Strain A77, an isolate from the Paris collection, is serum sensitive, poorly adherent to fibroblasts, and deficient in microcolony formation. Structural analysis indicates that the LOS of strain A77 lacks the galactose residue found in the N-acetyllactosamine portion of the strain 35000HP LOS as well as the sialic acid substitution. From an H. ducreyi 35000HP genomic DNA library, a clone complementing the defect in A77 was identified by immunologic screening with monoclonal antibody (MAb) 3F11, a MAb which recognizes theN-acetyllactosamine portion of strain 35000HP LOS. The clone contained a 4-kb insert that was sequenced. One open reading frame which encodes a protein with a molecular weight of 33,400 was identified. This protein has homology to glycosyltransferases ofHaemophilus influenzae, Haemophilus somnus,Neisseria species, and Pasteurella haemolytica. The putative H. ducreyi glycosyltransferase gene was insertionally inactivated, and an isogenic mutant of strain 35000HP was constructed. The most complex LOS glycoform produced by the mutant has a mobility on sodium dodecyl sulfate-polyacrylamide gel identical to that of the LOS of strain A77 and lacks the 3F11-binding epitope. Structural studies confirm that the most complex glycoform of the LOS isolated from the mutant lacks the galactose residue found in theN-acetyllactosamine portion of the strain 35000HP LOS. Although previously published data suggested that the serum-sensitive phenotype of A77 was due to the LOS mutation, we observed that the complemented A77 strain retained its serum-sensitive phenotype and that the galactosyltransferase mutant retained its serum-resistant phenotype. Thus, the serum sensitivity of strain A77 cannot be attributed to the galactosyltransferase mutation in strain A77.

scholarly journals Discovery of a 382-nt deletion during the early evolution of SARS-CoV-2

2020 ◽  
Author(s):  
Yvonne CF Su ◽  
Danielle E Anderson ◽  
Barnaby E Young ◽  
Feng Zhu ◽  
Martin Linster ◽  
...  
Keyword(s):  
Genetic Variants ◽  
Human Population ◽  
Host Adaptation ◽  
Open Reading Frame ◽  
N Gene ◽  
Regulatory Sequence ◽  
Reading Frame ◽  
Replicative Fitness ◽  
Similar Variation ◽  
Entire Open Reading Frame

To date, the SARS-CoV-2 genome has been considered genetically more stable than SARS-CoV or MERS-CoV. Here we report a 382-nt deletion covering almost the entire open reading frame 8 (ORF8) of SARS-CoV-2 obtained from eight hospitalized patients in Singapore. The deletion also removes the ORF8 transcription-regulatory sequence (TRS), which in turn enhances the downstream transcription of the N gene. We also found that viruses with the deletion have been circulating for at least four weeks. During the SARS-CoV outbreak in 2003, a number of genetic variants were observed in the human population [1], and similar variation has since been observed across SARS-related CoVs in humans and bats. Overwhelmingly these viruses had mutations or deletions in ORF8, that have been associated with reduced replicative fitness of the virus [2]. This is also consistent with the observation that towards the end of the outbreak sequences obtained from human SARS cases possessed an ORF8 deletion that may be associated with host adaptation [1]. We therefore hypothesise that the major deletion revealed in this study may lead to an attenuated phenotype of SARS-CoV-2.

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