scholarly journals Hypovirulence-Associated Double-Stranded RNA from Sclerotinia homoeocarpa Is Conspecific with Ophiostoma novo-ulmi Mitovirus 3a-Ld

2003 ◽  
Vol 93 (11) ◽  
pp. 1407-1414 ◽  
Author(s):  
F. Deng ◽  
R. Xu ◽  
G. J. Boland

The nucleotide sequence of the hypovirulence-associated double-stranded RNA (dsRNA) in hypovirulent isolate Sh12B of Sclerotinia homoeocarpa, the causal agent of dollar spot of turf grass, was determined. This large dsRNA (L-dsRNA) is 2,632 bp long and is A and U rich (61.0% A+U residues). One strand of this dsRNA contains an open reading frame (ORF) with the potential to encode a protein of 720 amino acids. This ORF contains 12 UGA codons, predicted to encode tryptophan in ascomycete mitochondria, and has a codon bias typical of mitochondrial genes, which is consistent with a mitochondrial localization of this dsRNA. The amino acid sequence contains conserved motifs typical of RNA-dependent RNA polymerases (RdRps). Sequence analyses of the nucleotide and RdRp-like protein revealed that the L-dsRNA is homologous with previously characterized mitochondrial viruses and dsRNAs from other phytopathogenic fungi, and shares 92.4% nucleotide and 95.1% amino acid sequence identities with the Ophiostoma novo-ulmi mitovirus 3a-Ld from Ophiostoma novo-ulmi, the causal agent of Dutch elm disease. The results indicate that these two dsRNAs are conspecific. This is the first report that a hypovirulence-associated dsRNA virus naturally occurs in two taxonomically distinct fungi, and indicates that horizontal transmission of this dsRNA virus may have occurred between these fungi.

1996 ◽  
Vol 40 (3) ◽  
pp. 616-620 ◽  
Author(s):  
A Bauernfeind ◽  
I Stemplinger ◽  
R Jungwirth ◽  
P Mangold ◽  
S Amann ◽  
...  

Plasmidic extended-spectrum beta-lactamases of Ambler class A are mostly inactive against ceftibuten. Salmonella typhimurium JMC isolated in Argentina harbors a bla gene located on a plasmid (pMVP-5) which confers transferable resistance to oxyiminocephalosporins, aztreonam, and ceftibuten. The beta-lactamase PER-2 (formerly ceftibutenase-1; CTI-1) is highly susceptible to inhibition by clavulanate and is located at a pI of 5.4 after isoelectric focusing. The blaPER-2 gene was cloned and sequenced. The nucleotide sequence of a 2.2-kb insert in vector pBluescript includes an open reading frame of 927 bp. Comparison of the deduced amino acid sequence of PER-2 with those of other beta-lactamases indicates that PER-2 is not closely related to TEM or SHV enzymes (25 to 26% homology). PER-2 is most closely related to PER-1 (86.4% homology), an Ambler class A enzyme first detected in Pseudomonas aeruginosa. An enzyme with an amino acid sequence identical to that of PER-1, meanwhile, was found in various members of the family Enterobacteriaceae isolated from patients in Turkey. Our data indicate that PER-2 and PER-1 represent a new group of Ambler class A extended-spectrum beta-lactamases. PER-2 so far has been detected only in pathogens (S. typhimurium, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis) isolated from patients in South America, while the incidence of PER-1-producing strains so far has been restricted to Turkey, where it occurs both in members of the family Enterobacteriaceae and in P. aeruginosa.


1993 ◽  
pp. 152-170 ◽  
Author(s):  
M. Yaguchi ◽  
M. Pusztai-Carey ◽  
C. Roy ◽  
W. K. Surewicz ◽  
P. R. Carey ◽  
...  

2002 ◽  
Vol 68 (6) ◽  
pp. 2731-2736 ◽  
Author(s):  
Hirokazu Nankai ◽  
Wataru Hashimoto ◽  
Kousaku Murata

ABSTRACT When cells of Bacillus sp. strain GL1 were grown in a medium containing xanthan as a carbon source, α-mannosidase exhibiting activity toward p-nitrophenyl-α-d-mannopyranoside (pNP-α-d-Man) was produced intracellularly. The 350-kDa α-mannosidase purified from a cell extract of the bacterium was a trimer comprising three identical subunits, each with a molecular mass of 110 kDa. The enzyme hydrolyzed pNP-α-d-Man (Km = 0.49 mM) and d-mannosyl-(α-1,3)-d-glucose most efficiently at pH 7.5 to 9.0, indicating that the enzyme catalyzes the last step of the xanthan depolymerization pathway of Bacillus sp. strain GL1. The gene for α-mannosidase cloned most by using N-terminal amino acid sequence information contained an open reading frame (3,144 bp) capable of coding for a polypeptide with a molecular weight of 119,239. The deduced amino acid sequence showed homology with the amino acid sequences of α-mannosidases belonging to glycoside hydrolase family 38.


1999 ◽  
Vol 26 (5) ◽  
pp. 495 ◽  
Author(s):  
Kazumasa Yoshida ◽  
Kiyoshi Tazaki

Three genomic clones (Rplec2, Rplec5 and Rplec6) and a cDNA clone (LECRPA4) that encoded lectin or lectin-related polypeptides were isolated from Robinia pseudoacacia L. A comparison of the nucleotide sequences of Rplec2 and a previously reported cDNA for the subunit indicated that Rplec2 encoded the 29 kDa subunit of the inner-bark lectin RPbAI. Rplec5 encoded a polypeptide whose deduced amino acid sequence was 96.1% identical to that of a subunit of seed lectin. The amino acid sequence deduced from the open reading frame of Rplec6 showed 61.1% identity to that encoded by Rplec5. LECRPA4 was isolated from an inner bark cDNA library and appeared to encode the 26 kDa subunit of inner-bark lectin RPbAII. The expression patterns of the various genes in tissues were examined by the reverse transcriptase-polymerase chain reaction (RT-PCR) with appropriate primers. Rplec2 transcripts were detected in the inner bark and roots. Rplec5 transcripts were detected in the inner bark, seeds and roots. No Rplec6 transcripts were detected in all tissues examined. LECRPA4 transcripts were found in leaves and in the inner bark. The level of expression of Rplec2 in the inner bark appeared to be similar in samples collected in different years and from different trees, whereas levels of expression of Rplec5 and LECRPA4 varied. These results suggest the differential regulation of expression of members of the lectin gene family in tissues of R. pseudoacacia. The nucleotide sequence data reported herein will appear in the DDBJ, EMBL and GenBank Nucleotide Sequence Databases under the accession numbers AB 012632 (Rplec2), AB012633 (Rplec5), AB012634 (Rplec6) and AB012635 (LECRPA4).


1998 ◽  
Vol 42 (11) ◽  
pp. 2906-2913 ◽  
Author(s):  
James M. Battisti ◽  
Laura S. Smitherman ◽  
D. Scott Samuels ◽  
Michael F. Minnick

ABSTRACT This study describes the first isolation and characterization of spontaneous mutants conferring natural resistance to an antibiotic for any Bartonella species. The Bartonella bacilliformis gyrB gene, which encodes the B subunit of DNA gyrase, was cloned and sequenced. The gyrB open reading frame (ORF) is 2,079 bp and encodes a deduced amino acid sequence of 692 residues, corresponding to a predicted protein of ∼77.5 kDa. Sequence alignment indicates that B. bacilliformis GyrB is most similar to the GyrB protein from Bacillus subtilis (40.1% amino acid sequence identity) and that it contains the longest N-terminal tail (52 residues) of any GyrB characterized to date. The cloned B. bacilliformis gyrB was expressed in an Escherichia coli S30 cell extract and was able to functionally complement a temperature-sensitive E. coli Cour gyrB mutant (strain N4177). We isolated and characterized spontaneous mutants of B. bacilliformis resistant to coumermycin A1, an antibiotic that targets GyrB. Sequence analysis of gyrB from 12 Cour mutants ofB. bacilliformis identified single nucleotide transitions at three separate loci in the ORF. The predicted amino acid substitutions resulting from these transitions are Gly to Ser at position 124 (Gly124→Ser), Arg184→Gln, and Thr214→Ala or Thr214→Ile, which are analogous to mutated residues found in previously characterized resistant gyrB genes fromBorrelia burgdorferi, E. coli,Staphylococcus aureus, and Haloferax sp. The Cour mutants are three to five times more resistant to coumermycin A1 than the wild-type parental strain.


1999 ◽  
Vol 65 (12) ◽  
pp. 5546-5553 ◽  
Author(s):  
Kazuhiro Iwashita ◽  
Tatsuya Nagahara ◽  
Hitoshi Kimura ◽  
Makoto Takano ◽  
Hitoshi Shimoi ◽  
...  

ABSTRACT We cloned the genomic DNA and cDNA of bglA, which encodes β-glucosidase in Aspergillus kawachii, based on a partial amino acid sequence of purified cell wall-bound β-glucosidase CB-1. The nucleotide sequence of the cloned bglA gene revealed a 2,933-bp open reading frame with six introns that encodes an 860-amino-acid protein. Based on the deduced amino acid sequence, we concluded that the bglA gene encodes cell wall-bound β-glucosidase CB-1. The amino acid sequence exhibited high levels of homology with the amino acid sequences of fungal β-glucosidases classified in subfamily B. We expressed the bglA cDNA inSaccharomyces cerevisiae and detected the recombinant β-glucosidase in the periplasm fraction of the recombinant yeast.A. kawachii can produce two extracellular β-glucosidases (EX-1 and EX-2) in addition to the cell wall-bound β-glucosidase.A. kawachii in which the bglA gene was disrupted produced none of the three β-glucosidases, as determined by enzyme assays and a Western blot analysis. Thus, we concluded that thebglA gene encodes both extracellular and cell wall-bound β-glucosidases in A. kawachii.


2000 ◽  
Vol 78 (6) ◽  
pp. 725-730 ◽  
Author(s):  
Francis Choy ◽  
Lisa Sharp ◽  
Derek A Applegarth

The H-protein is one of the four essential components (H-, L-, P-, and T-proteins) of the mammalian glycine cleavage enzyme complex, the major degradative pathway of glycine. We have isolated the full-length cDNA of the H-protein gene from the rabbit (Oryctolagus caniculus) by reverse transcription of liver poly-A mRNA and determined its nucleotide sequence (GenBank Acc. No. BankIt 318281 AF 231451). Similar to that in human, the rabbit H-protein gene possesses a 519-bp open reading frame that translates a 173-amino-acid (aa) protein. This reading frame is comprised of a 48-aa mitochondrial targeting sequence and a 125-aa residue that constitutes the mature mitochondrial matrix protein. In the mature protein region, there is a 95.5% nucleotide and 98.4% amino-acid sequence similarity to human. This conservation was also noted in the mature protein of the cow (Bos taurus) and chicken (Gallus domesticus), where there are a 94.1% and 85.3% nucleotide similarities, and 95.2% and 85.6% amino-acid sequence similarities, respectively. However, the targeting region is not as well conserved. Comparison of the rabbit targeting sequence to that in human, cow, and chicken reveals 84.0%, 79.2%, and 72.9% nucleotide, and 72.9%, 75.0%, and 54.2% amino-acid sequence similarities, respectively. These findings suggest that within the H-protein gene, the regions encoding the mitochondrial targeting and matrix protein may have evolved differently. Gene diversification in the former may reflect the species specificity in targeting proteins destined for the mitochondria, whereas homology in the latter suggests a very similar structure-function of the mature H-protein among these species. This homology in structure-function likely accounts for the observation that non-human H-protein can replace the human protein in the activity assay of the glycine cleavage enzyme system. This includes the biochemical diagnosis of non-ketotic hyperglycinemia (NKH) resulting from defects other than the H-protein, e.g., mutation(s) in the P-protein.Key words: glycine cleavage enzyme, H-protein, sequence comparison, non-ketotic hyperglycinemia.


2004 ◽  
Vol 70 (3) ◽  
pp. 1570-1575 ◽  
Author(s):  
Dae Heoun Baek ◽  
Jae Jun Song ◽  
Seok-Joon Kwon ◽  
Chung Park ◽  
Chang-Min Jung ◽  
...  

ABSTRACT A new thermostable dipeptidase gene was cloned from the thermophile Brevibacillus borstelensis BCS-1 by genetic complementation of the d-Glu auxotroph Escherichia coli WM335 on a plate containing d-Ala-d-Glu. Nucleotide sequence analysis revealed that the gene included an open reading frame coding for a 307-amino-acid sequence with an M r of 35,000. The deduced amino acid sequence of the dipeptidase exhibited 52% similarity with the dipeptidase from Listeria monocytogenes. The enzyme was purified to homogeneity from recombinant E. coli WM335 harboring the dipeptidase gene from B. borstelensis BCS-1. Investigation of the enantioselectivity (E) to the P1 and P1′ site of Ala-Ala revealed that the ratio of the specificity constant (k cat /Km ) for l-enantioselectivity to the P1 site of Ala-Ala was 23.4 � 2.2 [E = (k cat /Km ) l,d /(k cat /Km ) d,d ], while the d-enantioselectivity to the P1′ site of Ala-Ala was 16.4 � 0.5 [E = (k cat /Km ) l,d /(k cat /Km ) l,l ] at 55�C. The enzyme was stable up to 55�C, and the optimal pH and temperature were 8.5 and 65�C, respectively. The enzyme was able to hydrolyze l-Asp-d-Ala, l-Asp-d-AlaOMe, Z-d-Ala-d-AlaOBzl, and Z-l-Asp-d-AlaOBzl, yet it could not hydrolyze d-Ala-l-Asp, d-Ala-l-Ala, d-AlaNH2, and l-AlaNH2. The enzyme also exhibited β-lactamase activity similar to that of a human renal dipeptidase. The dipeptidase successfully synthesized the precursor of the dipeptide sweetener Z-l-Asp-d-AlaOBzl.


Genetics ◽  
1992 ◽  
Vol 131 (3) ◽  
pp. 531-539 ◽  
Author(s):  
C Bornaes ◽  
J G Petersen ◽  
S Holmberg

Abstract The catabolic L-serine (L-threonine) dehydratase of Saccharomyces cerevisiae allows the yeast to grow on media with L-serine or L-threonine as sole nitrogen source. Previously we have cloned the CHA1 gene by complementation of a mutant, cha1, lacking the dehydratase activity. Here we present the DNA sequence of a 1,766-bp fragment of the CHA1 region encompassing an open reading frame of 1080 bp. Comparison of the predicted amino acid sequence of the CHA1 polypeptide with that of other serine/threonine dehydratases revealed several blocks of sequence homology. Thus, the amino acid sequence of rat liver serine dehydratase (SDH2) and the CHA1 polypeptide are 44% homologous allowing for conservative substitutions, while 36% similarity is found between the catabolic threonine dehydratase (tdcB) of Escherichia coli and the CHA1 protein. This strongly suggests that CHA1 is the structural gene for the yeast catabolic serine (threonine) dehydratase. S1-nuclease mapping of the CHA1 mRNA ends showed a major transcription initiation site corresponding to an untranslated leader of about 19 nucleotides, while a major polyadenylation site was located about 86 nucleotides downstream from the open reading frame. Furthermore, we have mapped the chromosomal position of the CHA1 gene to less than 0.5 kb centromere proximal to HML on the left arm of chromosome III.


1999 ◽  
Vol 6 (3) ◽  
pp. 392-399 ◽  
Author(s):  
Jere W. McBride ◽  
Xue-jie Yu ◽  
David H. Walker

ABSTRACT A gene encoding a 28-kDa protein of Ehrlichia canis was cloned, sequenced, and expressed, and a comparative molecular analysis with homologous genes of E. canis, Cowdria ruminantium, and Ehrlichia chaffeensis was performed. The complete gene has an 834-bp open reading frame encoding a protein of 278 amino acids with a predicted molecular mass of 30.5 kDa. An N-terminal signal sequence was identified, suggesting that the protein undergoes posttranslational modification to a mature 27.7-kDa protein (P28). The E. canis p28 gene has significant nucleic acid and amino acid sequence homologies with the E. chaffeensisouter membrane protein-1 (omp-1) gene family, with theCowdria ruminantium map-1 gene, and with other E. canis 28-kDa-protein genes. Southern blotting revealed the presence of at least two additional homologous p28 gene copies in the E. canis genome, confirming thatp28 is a member of a polymorphic multiple-gene family. Amino acid sequence analysis revealed that E. canis P28 has four variable regions, and it shares similar surface-exposed regions, antigenicity, and T-cell motifs with E. chaffeensis P28. The p28 genes from seven different E. canisisolates were identical, indicating that the gene for this major immunoreactive protein is highly conserved. In addition, reactivity of sera from clinical cases of canine ehrlichiosis with the recombinant P28 demonstrated that the recombinant protein may be a reliable serodiagnostic antigen.


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