In vitro cellulolytic activity of the plant pathogen Clavibacter michiganensis subsp. sepedonicus

1995 ◽  
Vol 41 (10) ◽  
pp. 877-888 ◽  
Author(s):  
Debra Baer ◽  
Neil C. Gudmestad

The activity of four Clavibacter michiganensis subsp. sepedonicus strains against various cellulose substrates was investigated. Sixty-seven Clavibacter michiganensis subsp. sepedonicus strains grew well on media amended with carboxymethylcellulose, 64 strains produced zones of hydrolysis. Endoglucanase activity was optimal at 37 °C and pH 6.0 against carboxymethylcellulose incorporated in plate assays. Zymogram and sodium dodecyl sulfate – polyacrylamide gel electrophoresis revealed the presence of a protein band corresponding to the cellulolytic activity in the molecular weight (MW) range of approximately 28 000. Protein bands in the same range were detected in five Clavibacter michiganensis subsp. sepedonicus strains. Studies on crude enzyme extracts of Clavibacter michiganensis subsp. sepedonicus strain N-1-1 revealed that p-nitrophenyl β-D-cellobioside (pNPC) was hydrolyzed, with optimal activity at 37 °C and pH 7.0.Key words: cellulase, endo-1,4-β-glucanase (EC 3.2.1.4), Corynebacterium sepedonicum, Solanum tuberosum.

2006 ◽  
Vol 80 (1) ◽  
pp. 306-313 ◽  
Author(s):  
Rachel L. Roper

ABSTRACT The vaccinia virus A35R gene is highly conserved among poxviruses and encodes a previously uncharacterized hydrophobic acidic protein. Western blotting with anti-A35R peptide antibodies indicated that the protein is expressed early in infection and resolved as a single sharp band of ∼23 kDa, slightly higher than the 20 kDa predicted from its sequence. The protein band appeared to be the same molecular weight on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, whether expressed in an in vitro transcription/translation system without microsomes or expressed in infected cells, suggesting that it was not glycosylated. A mutant virus with the A35R gene deleted (vA35Δ) formed wild-type-sized plaques on all cell lines tested (human, monkey, mouse, and rabbit); thus, A35R is not required for replication and does not appear to be a host range gene. Although the A35R protein is hydrophobic, it is unlikely to be an integral membrane protein, as it partitioned to the aqueous phase during TX-114 partitioning. The protein could not be detected in virus-infected cell supernatants. A35R localized intracellularly to the virus factories, where the first stages of morphogenesis occur. The vA35Δ mutant formed near-normal levels of the various morphogenic stages of infectious virus particles and supported normal acid-induced fusion of virus-infected cells. Despite normal growth and morphogenesis in vitro, the vA35Δ mutant virus was attenuated in intranasal challenge of mice compared to wild-type and A35R rescue virus. Thus, the intracellular A35R protein plays a role in virulence. The A35R has little homology to any protein outside of poxviruses, suggesting a novel virulence mechanism.


1998 ◽  
Vol 88 (4) ◽  
pp. 306-310 ◽  
Author(s):  
C. Alarcón ◽  
J. Castro ◽  
F. Muñoz ◽  
P. Arce-Johnson ◽  
J. Delgado

The gram-positive tomato pathogen Clavibacter michiganensis subsp. michiganensis induced a local necrotic response on four-o'clock (Mirabilis jalapa) and tobacco (Nicotiana tabacum) plants. This necrosis response was characteristic of the hypersensitive response (HR). The cell-free culture supernatant from strain CMM623 also induced a necrosis that was phenotypically similar to that induced by the bacteria. Inhibitors of plant metabolism suppressed the necrotic reaction of both M. jalapa and tobacco. The HR-inducing activity present in the supernatant was heat stable, sensitive to proteases, and had an apparent molecular mass in the range of 35 to 50 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The properties observed for the necrosis-inducing activity resembled harpin and PopA described from gram-negative phytopathogenic bacteria.


1982 ◽  
Vol 2 (4) ◽  
pp. 412-425 ◽  
Author(s):  
S I Reed ◽  
J Ferguson ◽  
J C Groppe

The CDC28 gene was subcloned from a plasmid containing a 6.5-kilobase-pair segment of Saccharomyces cerevisiae DNA YRp7(CDC28-3) by partial digestion with Sau3A and insertion of the resulting fragments into the BamHI sites of YRp7 and pRC1. Recombinant plasmids were obtained containing inserts of 4.4 and 3.1 kilobase pairs which were capable of complementing a cdc28(ts) mutation. R-loop analysis indicated that each yeast insert contained two RNA coding regions of about 0.8 and 1.0 kilobase pairs, respectively. In vitro mutagenesis experiments suggested that the smaller coding region corresponded to the CDC28 gene. When cellular polyadenylic acid-containing RNA, separated by agarose gel electrophoresis after denaturation with glyoxal and transferred to nitrocellulose membrane, was reacted with labeled DNA from the smaller coding region, and RNA species of about 1 kilobase in length was detected. Presumably, the discrepancy in size between the R-loop and electrophoretic determinations is due to a segment of polyadenylic acid which is excluded from the R-loops. By using hybridization of the histone H2B mRNAs to an appropriate probe as a previously determined standards, it was possible to estimate the number of CDC28 mRNA copies per haploid cell as between 6 and 12 molecules. Hybrid release translation performed on the CDC29 mRNA directed the synthesis of a polypeptide of 27,000 daltons, as determined by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. This polypeptide was not synthesized when mRNA prepared from a cdc28 nonsense mutant was translated in a parallel fashion. However, if the RNA from a cell containing the CDC28 gene on a plasmid maintained at a high copy number was translated, the amount of in vitro product was amplified fivefold.


2007 ◽  
Vol 73 (7) ◽  
pp. 2247-2250 ◽  
Author(s):  
Sirinat Srionnual ◽  
Fujitoshi Yanagida ◽  
Li-Hsiu Lin ◽  
Kuang-Nan Hsiao ◽  
Yi-sheng Chen

ABSTRACT Weissella cibaria 110, isolated from the Thai fermented fish product plaa-som, was found to produce a bacteriocin active against some gram-positive bacteria. Bacteriocin activity was not eliminated by exposure to high temperatures or catalase but was destroyed by exposure to the proteolytic enzymes proteinase K and trypsin. The bacteriocin from W. cibaria 110 was purified, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the purified bacteriocin contained one protein band that was approximately 2.5 kDa in size. Mass spectrometry analysis showed the mass of the peptide to be approximately 3,487.8 Da. N-terminal amino acid sequence analysis was performed, and 27 amino acids were identified. Because it has no similarity to other known bacteriocins, this bacteriocin was defined as a new bacteriocin and termed weissellicin 110.


1994 ◽  
Vol 14 (9) ◽  
pp. 6164-6170
Author(s):  
P P Sadhale ◽  
N A Woychik

We identified a partially sequenced Saccharomyces cerevisiae gene which encodes a protein related to the S. cerevisiae RNA polymerase II subunit, RPB7. Several lines of evidence suggest that this related gene, YKL1, encodes the RNA polymerase III subunit C25. C25, like RPB7, is present in submolar ratios, easily dissociates from the enzyme, is essential for cell growth and viability, but is not required in certain transcription assays in vitro. YKL1 has ABF-1 and PAC upstream sequences often present in RNA polymerase subunit genes. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis mobility of the YKL1 gene product is equivalent to that of the RNA polymerase III subunit C25. Finally, a C25 conditional mutant grown at the nonpermissive temperature synthesizes tRNA at reduced rates relative to 5.8S rRNA, a hallmark of all characterized RNA polymerase III mutants.


1977 ◽  
Vol 163 (2) ◽  
pp. 369-378 ◽  
Author(s):  
P R Dunkley ◽  
H Holmes ◽  
R Rodnight

Synaptic-membrane fragments from ox cerebral cortex contain basal and cyclic AMP-stimulated protein kinase(s) that transfer 32P from [gamma-32P]ATP to hydroxyl groups of serine and threonine residues in membrane-protein substrates. In the present work, labelled membrane fragments were partitioned into soluble and insoluble fractions with Triton X-100, Nonidet P. 40, sodium deoxycholate and urea, and the distribution of 32P-labelled protein in the fractions was determined by polyacrylamide-gel electrophoresis and radioautography. A high percentage of phosphorylated protein sustrates remained insoluble, including those whose phosphorylation was most highly stimulated by cyclic AMP. Whole membrane fragments and samples prepared by detergent extraction were fractionated on Sepharose 6B columns in the presence of low concentrations of sodium dodecyl sulphate and pooled fractions were analysed by polyacrylamide-gel electrophoresis and radioautography. Phosphorylated proteins were fractionated on the basis of their molecular weight, but homogeneous protein was not obtained. The results are discussed in relation to the techniques used and the results obtained in other laboratories.


1998 ◽  
Vol 66 (9) ◽  
pp. 4374-4381 ◽  
Author(s):  
John C. McMichael ◽  
Michael J. Fiske ◽  
Ross A. Fredenburg ◽  
Deb N. Chakravarti ◽  
Karl R. VanDerMeid ◽  
...  

ABSTRACT The UspA1 and UspA2 proteins of Moraxella catarrhalisare potential vaccine candidates for preventing disease caused by this organism. We have characterized both proteins and evaluated their vaccine potential using both in vitro and in vivo assays. Both proteins were purified from the O35E isolate by Triton X-100 extraction, followed by ion-exchange and hydroxyapatite chromatography. Analysis of the sequences of internal peptides, prepared by enzymatic and chemical cleavage of the proteins, revealed that UspA1 and UspA2 exhibited distinct structural differences but shared a common sequence including an epitope recognized by the monoclonal antibody 17C7. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), purified UspA1 exhibited a molecular weight of approximately 350,000 when unheated and a molecular weight of 100,000 after being heated for 10 min at 100°C. In contrast, purified UspA2 exhibited an apparent molecular weight of 240,000 by SDS-PAGE that did not change with the length of time of heating. Their sizes as determined by gel filtration were 1,150,000 and 830,000 for UspA1 and UspA2, respectively. Preliminary results indicate the proteins have separate functions in bacterial pathogenesis. Purified UspA1 was found to bind HEp-2 cells, and sera against UspA1, but not against UspA2, blocked binding of the O35E isolate to the HEp-2 cells. UspA1 also bound fibronectin and appears to have a role in bacterial attachment. Purified UspA2, however, did not bind fibronectin but had an affinity for vitronectin. Both proteins elicited bactericidal antibodies in mice to homologous and heterologous disease isolates. Finally, mice immunized with each of the proteins, followed by pulmonary challenge with either the homologous or a heterologous isolate, cleared the bacteria more rapidly than mock-immunized mice. These results suggest that UspA1 and UspA2 serve different virulence functions and that both are promising vaccine candidates.


1983 ◽  
Vol 59 (1) ◽  
pp. 81-103 ◽  
Author(s):  
R. Crossley ◽  
D.V. Holberton

Proteins from the axonemes and disc cytoskeleton of Giardia lamblia have been examined by sodium dodecyl sulphate/polyacrylamide gel electrophoresis. In addition to tubulin and the 30 X 10(3) molecular weight disc protein, at least 18 minor components copurify with the two major proteins in Triton-insoluble structures. The most prominent minor bands have the apparent molecular weights of 110 X 10(3), 95 X 10(3) and 81 X 10(3). Protein of 30 X 10(3) molecular weight accounts for about 20% of organelle protein on gels. In continuous 25 mM-Tris-glycine buffer it migrates mostly as a close-spaced doublet of polypeptides, which are here given the name giardins. Giardia tubulin and giardin have been purified by gel filtration chromatography in the presence of sodium dodecyl sulphate. Well-separated fractions were obtained that could be further characterized. Both proteins are heterogeneous when examined by isoelectric focusing. Five tubulin chains were detected by PAGE Blue 83 dye-binding after focusing in a broad-range ampholyte gel. Giardin is slightly less acidic than tubulin. On gels it splits into four major and four minor chains with isoelectric points in the pI range from 5.8 to 6.2. The amino acid composition of the giardin fraction has been determined, and compared to Giardia tubulin and a rat brain tubulin standard. Giardins are rich in helix-forming residues, particularly leucine. They have a low content of proline and glycine; therefore they may have extensive alpha-helical regions and be rod-shaped. As integral proteins of disc microribbons, giardins in vivo associate closely with tubulin. The properties of giardins indicate that in a number of respects - molecular size, charge, stoichiometry - their structural interaction with tubulin assemblies will be different from other tubulin-accessory protein copolymers studied in vitro.


2005 ◽  
Vol 4 (11) ◽  
pp. 1951-1958 ◽  
Author(s):  
Felix D. Bastida-Corcuera ◽  
Cheryl Y. Okumura ◽  
Angie Colocoussi ◽  
Patricia J. Johnson

ABSTRACT The extracellular human pathogen Trichomonas vaginalis is covered by a dense glycocalyx thought to play a role in host-parasite interactions. The main component of the glycocalyx is lipophosphoglycan (LPG), a polysaccharide anchored in the plasma membrane by inositol phosphoceramide. To study the role of LPG in trichomonads, we produced T. vaginalis LPG mutants by chemical mutagenesis and lectin selection and characterized them using morphological, biochemical, and functional assays. Two independently selected LPG mutants, with growth rates comparable to that of the wild-type (parent) strain, lost the ability to bind the lectins Ricinnus comunis agglutinin I (RCA120) and wheat germ agglutinin, indicating alterations in surface galactose and glucosamine residues. LPG isolated from mutants migrated faster than parent strain LPG on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting the mutants had shorter LPG molecules. Dionex high-performance anion exchange chromatography with pulsed amperometric detection analyses revealed galactosamine, glucosamine, galactose, glucose, mannose/xylose, and rhamnose as the main monosaccharides of T. vaginalis parent strain LPG. LPG from both mutants showed a reduction of galactose and glucosamine, corresponding with the reduced size of their LPG molecules and inability to bind the lectins RCA120 and wheat germ agglutinin. Mutant parasites were defective in attachment to plastic, a characteristic associated with avirulent strains of T. vaginalis. Moreover, the mutants were less adherent and less cytotoxic to human vaginal ectocervical cells in vitro than the parental strain. Finally, while parent strain LPG could inhibit the attachment of parent strain parasites to vaginal cells, LPG from either mutant could not inhibit attachment. These combined results demonstrate that T. vaginalis adherence to host cells is LPG mediated and that an altered LPG leads to reduced adherence and cytotoxicity of this parasite.


2005 ◽  
Vol 79 (12) ◽  
pp. 7283-7290 ◽  
Author(s):  
Tomoichiro Oka ◽  
Kazuhiko Katayama ◽  
Satoko Ogawa ◽  
Grant S. Hansman ◽  
Tsutomu Kageyama ◽  
...  

ABSTRACT The genome of Sapovirus (SaV), a causative agent of gastroenteritis in humans and swine, contains either two or three open reading frames (ORFs). Functional motifs characteristic to the 2C-like NTPase (NTPase), VPg, 3C-like protease (Pro), 3D-like RNA-dependent RNA polymerase (Pol), and capsid protein (VP1) are encoded in the ORF1 polyprotein, which is afterwards cleaved into the nonstructural and structural proteins. We recently determined the complete genome sequence of a novel human SaV strain, Mc10, which has two ORFs. To investigate the proteolytic cleavage of SaV ORF1 and the function of protease on the cleavage, both full-length and truncated forms of the ORF1 polyprotein either with or without mutation in 1171Cys to Ala of the GDCG motif were expressed in an in vitro coupled transcription-translation system. The translation products were analyzed directly by sodium dodecyl sulfate-polyacrylamide gel electrophoresis or by immunoprecipitation with region-specific antibodies. The ORF1 polyprotein was processed into at least 10 major proteins: p11, p28, p35, p32, p14, p70, p60, p66, p46, and p120. Seven of these products were arranged in the following order: NH2-p11-p28-p35(NTPase)-p32-p14(VPg)-p70(Pro-Pol)-p60(VP1)-COOH. p66, p46 and p120 were precursors of p28-p35 (NTPase), p32-p14 (VPg), and p32-p14 (VPg)-p70 (Pro-Pol), respectively. Mutagenesis in the 3C-like protease motif fully abolished the proteolytic activity. The cleavage map of SaV ORF1 is similar to those of other heretofore known members of the family Caliciviridae, especially to rabbit hemorrhagic disease virus, a member of the genus Lagovirus.


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