bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of Maltogenic Amylase and Pullulanase in Maltodextrin and Glycogen Metabolism of
Bacillus subtilis
168
Authors: Shim Jae-Hoon , Park Jong-Tae , Hong Jung-Sun , Kim Ki Woo , Kim Myo-Jeong , Auh Jung-Hyuk , Kim Young-Wan , Park Cheon-Seok , Boos Winfried , Kim Jung-Wan , Park Kwan-Hwa 
Published: May 2009

ABSTRACT

The physiological functions of two amylolytic enzymes, a maltogenic amylase (MAase) encoded by
yvdF
and a debranching enzyme (pullulanase) encoded by
amyX
, in the carbohydrate metabolism of
Bacillus subtilis
168 were investigated using
yvdF
,
amyX
, and
yvdF amyX
mutant strains. An immunolocalization study revealed that YvdF was distributed on both sides of the cytoplasmic membrane and in the periplasm during vegetative growth but in the cytoplasm of prespores. Small carbohydrates such as maltoheptaose and β-cyclodextrin (β-CD) taken up by wild-type
B. subtilis
cells via two distinct transporters, the Mdx and Cyc ABC transporters, respectively, were hydrolyzed immediately to form smaller or linear maltodextrins. On the other hand, the
yvdF
mutant exhibited limited degradation of the substrates, indicating that, in the wild type, maltodextrins and β-CD were hydrolyzed by MAase while being taken up by the bacterium. With glycogen and branched β-CDs as substrates, pullulanase showed high-level specificity for the hydrolysis of the outer side chains of glycogen with three to five glucosyl residues. To investigate the roles of MAase and pullulanase in glycogen utilization, the following glycogen-overproducing strains were constructed: a
glg
mutant with a wild-type background,
yvdF glg
and
amyX glg
mutants, and a
glg
mutant with a double mutant (DM) background. The
amyX glg
and
glg
DM strains accumulated significantly larger amounts of glycogen than the
glg
mutant, while the
yvdF glg
strain accumulated an intermediate amount. Glycogen samples from the
amyX glg
and
glg
DM strains exhibited average molecular masses two and three times larger, respectively, than that of glycogen from the
glg
mutant. The results suggested that glycogen breakdown may be a sequential process that involves pullulanase and MAase, whereby pullulanase hydrolyzes the α-1,6-glycosidic linkage at the branch point to release a linear maltooligosaccharide that is then hydrolyzed into maltose and maltotriose by MAase.
Oleate Hydratase Catalyzes the Hydration of a Nonactivated Carbon-Carbon Bond
Authors: Bevers Loes E. , Pinkse Martijn W. H. , Verhaert Peter D. E. M. , Hagen Wilfred R. 
Published: May 2009

ABSTRACT

The hydration of oleic acid into 10-hydroxystearic acid was originally described for a
Pseudomonas
cell extract almost half a century ago. In the intervening years, the enzyme has never been characterized in any detail. We report here the isolation and characterization of oleate hydratase (EC 4.2.1.53) from
Elizabethkingia meningoseptica
.
Characterization of a Gene Cluster Involved in 4-Chlorocatechol Degradation byPseudomonas reinekeiMT1
Authors: Cámara Beatriz , Nikodem Patricia , Bielecki Piotr , Bobadilla Roberto , Junca Howard , Pieper Dietmar H. 
Published: May 2009

ABSTRACTPseudomonas reinekeiMT1 has previously been reported to degrade 4- and 5-chlorosalicylate by a pathway with 4-chlorocatechol, 3-chloromuconate, 4-chloromuconolactone, and maleylacetate as intermediates, and a gene cluster channeling various salicylates into an intradiol cleavage route has been reported. We now report that during growth on 5-chlorosalicylate, besides a novel (chloro)catechol 1,2-dioxygenase, C12OccaA, a novel (chloro)muconate cycloisomerase, MCIccaB, which showed features not yet reported, was induced. This cycloisomerase, which was practically inactive with muconate, evolved for the turnover of 3-substituted muconates and transforms 3-chloromuconate into equal amounts ofcis-dienelactone and protoanemonin, suggesting that it is a functional intermediate between chloromuconate cycloisomerases and muconate cycloisomerases. The corresponding genes,ccaA(C12OccaA) andccaB(MCIccaB), were located in a 5.1-kb genomic region clustered with genes encodingtrans-dienelactone hydrolase (ccaC) and maleylacetate reductase (ccaD) and a putative regulatory gene,ccaR, homologous to regulators of the IclR-type family. Thus, this region includes genes sufficient to enable MT1 to transform 4-chlorocatechol to 3-oxoadipate. Phylogenetic analysis showed that C12OccaAand MCIccaBare only distantly related to previously described catechol 1,2-dioxygenases and muconate cycloisomerases. Kinetic analysis indicated that MCIccaBand the previously identified C12OsalD, rather than C12OccaA, are crucial for 5-chlorosalicylate degradation. Thus, MT1 uses enzymes encoded by a completely novel gene cluster for degradation of chlorosalicylates, which, together with a gene cluster encoding enzymes for channeling salicylates into theortho-cleavage pathway, form an effective pathway for 4- and 5-chlorosalicylate mineralization.
Biosynthesis of Aliphatic Polyketides by Type III Polyketide Synthase and Methyltransferase in
Bacillus subtilis
Authors: Nakano Chiaki , Ozawa Hiroki , Akanuma Genki , Funa Nobutaka , Horinouchi Sueharu 
Published: May 2009

ABSTRACT

Type III polyketide synthases (PKSs) synthesize a variety of aromatic polyketides in plants, fungi, and bacteria. The bacterial genome projects predicted that probable type III PKS genes are distributed in a wide variety of gram-positive and -negative bacteria. The gram-positive model microorganism
Bacillus subtilis
contained the
bcsA
-
ypbQ
operon, which appeared to encode a type III PKS and a methyltransferase, respectively. Here, we report the characterization of
bcsA
(renamed
bpsA
, for
Bacillus
pyrone synthase, on the basis of its function) and
ypbQ
, which are involved in the biosynthesis of aliphatic polyketides. In vivo analysis demonstrated that BpsA was a type III PKS catalyzing the synthesis of triketide pyrones from long-chain fatty acyl-coenzyme A (CoA) thioesters as starter substrates and malonyl-CoA as an extender substrate, and YpbQ was a methyltransferase acting on the triketide pyrones to yield alkylpyrone methyl ethers. YpbQ thus was named BpsB because of its functional relatedness to BpsA. In vitro analysis with histidine-tagged BpsA revealed that it used broad starter substrates and produced not only triketide pyrones but also tetraketide pyrones and alkylresorcinols. Although the aliphatic polyketides were expected to localize in the membrane and play some role in modulating the rigidity and properties of the membrane, no detectable phenotypic changes were observed for a
B. subtilis
mutant containing a whole deletion of the
bpsA-bpsB
operon.
Identification of a Catabolite-Responsive Element Necessary for Regulation of the
cry4A
Gene of
Bacillus thuringiensis
subsp.
israelensis
Authors: Kant Sashi , Kapoor Rupam , Banerjee Nirupama 
Published: May 2009

ABSTRACT

Bacillus thuringiensis
subsp.
israelensis
produces a potent mosquitocidal protein, Cry4A. We have identified a 15-bp catabolite responsive element (
cre
), overlapping the −35 element of the
cry4A
promoter. Changing a guanine to adenine at position −49 in the promoter abolished glucose catabolite repression of
cry4A
and enhanced promoter activity two- to threefold. This
cis
regulatory element is essential for controlled toxin synthesis, vital to evolutionary success of
B. thuringiensis
subsp.
israelensis
.
Molecular Characterization and Lytic Activities of
Streptococcus agalactiae
Bacteriophages and Determination of Lysogenic-Strain Features
Authors: Domelier Anne-Sophie , van der Mee-Marquet Nathalie , Sizaret Pierre-Yves , Héry-Arnaud Geneviève , Lartigue Marie-Frédérique , Mereghetti Laurent , Quentin Roland 
Published: May 2009

ABSTRACT

The application of mitomycin C induction to 114 genetically diverse
Streptococcus agalactiae
strains generated 36 phage suspensions. On electron microscopy of the phage suspensions, it was possible to assign the phages to the
Siphoviridae
family, with three different morphotypes (A, B, and C). Phage genetic diversity was evaluated by a PCR-based multilocus typing method targeting key modules located in the packaging, structural, host lysis, lysogeny, replication, and transcriptional regulation clusters and in the integrase genes and by DNA digestion with EcoRI, HindIII, and ClaI. Thirty-three phages clustering in six distantly related molecular phage groups (I to VI) were identified. Each molecular group was morphotype specific except for morphotype A phages, which were found in five of the six phage groups. The various phage groups defined on the basis of molecular group and morphotype had specific lytic activities, suggesting that each recognized particular host cell targets and had particular lytic mechanisms. Comparison of the characteristics of lysogenic and propagating strains showed no difference in the serotype or clonal complex (CC) identified by multilocus sequence typing. However, all the lysogenic CC17 and CC19 strains presented catabolic losses due to a lack of catabolic decay of
dl
-alpha-glycerol-phosphate substrates (CC17) and of alpha-
d
-glucose-1-phosphate (CC19). Moreover, the phages from CC17 lysogenic strains displayed lytic replication in bacterial hosts from all
S. agalactiae
phylogenetic lineages other than CC23, whereas phages obtained from non-CC17 lysogenic strains lysed bacteria of similar evolutionary origin. Our findings suggest that the adaptive evolution of
S. agalactiae
exposed the bacteria of this species to various phage-mediated horizontal gene transfers, which may have affected the fitness of the more virulent clones.
Characterization of γ-Butyrolactone Autoregulatory Signaling Gene Homologs in the Angucyclinone Polyketide WS5995B ProducerStreptomyces acidiscabies
Authors: Healy Frank G. , Eaton Kevin P. , Limsirichai Prajit , Aldrich Joel F. , Plowman Alaina K. , King Russell R. 
Published: May 2009

ABSTRACTOrganisms belonging to the genusStreptomycesproduce numerous important secondary metabolites and undergo a sophisticated morphological differentiation program. In many instances these processes are under the control of γ-butyrolactone (GBL) autoregulatory systems.Streptomyces acidiscabiesstrain 84.104 produces the secondary metabolite aromatic angucyclinone polyketide WS5995B. In order to explore the role of GBL regulatory circuitry in WS5995B production and morphogenesis inS. acidiscabies, a gene cluster encoding GBL autoregulatory signaling homologs was identified and characterized. Two GBL receptor homologs,sabRandsabS, were found flanking a GBL synthase homologsabA. Strains carrying mutations insabSproduced elevated levels of WS5995B and displayed conditional morphological defects reminiscent of defects seen inStreptomyces bldAmutants. Notably,sabSpossesses a TTA codon predicted to be recognized by tRNAleu.sabAmutants produced higher levels of WS5995B than the wild-type strain but to a lesser extent than the levels of WS5995B seen insabSmutants. Purified recombinant SabR and SabS were tested for their abilities to bind predicted AT-rich autoregulatory element (ARE) boxes within thesabRASregion. SabS did not bind any DNA sequences in this region, while SabR bound an ARE box in the region upstream ofsabS. Quantitative reverse transcription-PCR analysis revealed higher levels ofsabStranscript insabRmutants than in the wild-type strain, suggesting thatsabSexpression is repressed by SabR. Based on these data, we propose that theS. acidiscabies sabRASgenes encode components of a signaling pathway which participates in the regulation of WS5995B production and morphogenesis.
Nucleotide Excision Repair Is a Predominant Mechanism for Processing Nitrofurazone-Induced DNA Damage in
Escherichia coli
Authors: Ona Katherine R. , Courcelle Charmain T. , Courcelle Justin 
Published: May 2009

ABSTRACT

Nitrofurazone is reduced by cellular nitroreductases to form
N
2
-deoxyguanine (
N
2
-dG) adducts that are associated with mutagenesis and lethality. Much attention recently has been given to the role that the highly conserved polymerase IV (Pol IV) family of polymerases plays in tolerating adducts induced by nitrofurazone and other
N
2
-dG-generating agents, yet little is known about how nitrofurazone-induced DNA damage is processed by the cell. In this study, we characterized the genetic repair pathways that contribute to survival and mutagenesis in
Escherichia coli
cultures grown in the presence of nitrofurazone. We find that nucleotide excision repair is a primary mechanism for processing damage induced by nitrofurazone. The contribution of translesion synthesis to survival was minor compared to that of nucleotide excision repair and depended upon Pol IV. In addition, survival also depended on both the RecF and RecBCD pathways. We also found that nitrofurazone acts as a direct inhibitor of DNA replication at higher concentrations. We show that the direct inhibition of replication by nitrofurazone occurs independently of DNA damage and is reversible once the nitrofurazone is removed. Previous studies that reported nucleotide excision repair mutants that were fully resistant to nitrofurazone used high concentrations of the drug (200 μM) and short exposure times. We demonstrate here that these conditions inhibit replication but are insufficient in duration to induce significant levels of DNA damage.
Extracytoplasmic Function σ Factors with Overlapping Promoter Specificity Regulate Sublancin Production in
Bacillus subtilis
Authors: Luo Yun , Helmann John D. 
Published: May 2009

ABSTRACT

Bacillus subtilis
harbors seven extracytoplasmic function (ECF) σ factors. At least three ECF σ factors (σ
M
, σ
W
, and σ
X
) are induced by, and provide resistance to, antibiotics and other agents eliciting cell envelope stress. Here, we report that ECF σ factors also contribute to antibiotic production.
B. subtilis
168 strains that are lysogenic for the SPβ bacteriophage produce sublancin, which inhibits the growth of other, nonlysogenic strains. Genetic studies demonstrate that synthesis of sublancin is largely dependent on σ
X
, with a smaller contribution from σ
M
. A
sigM sigX
double mutant is unable to produce sublancin. This defect is primarily due to the fact that the sublancin biosynthesis is positively activated by the transition state regulator and AbrB paralog Abh, which counteracts transcriptional repression of the sublancin biosynthesis operon by AbrB. Ectopic expression of
abh
bypasses the requirement for σ
M
or σ
X
in sublancin synthesis, as does an
abrB
mutation. In addition to their major role in regulating sublancin expression by activating
abh
transcription, σ
X
and σ
M
also have a second role as positive regulators of sublancin expression that is independent of AbrB and Abh. Since sublancin resistance in nonlysogens is largely dependent on σ
W
, ECF σ factors control both sublancin production and resistance.
Biochemical Evidence for ToxR and ToxJ Binding to the
tox
Operons of
Burkholderia glumae
and Mutational Analysis of ToxR
Authors: Kim Jinwoo , Oh Jonghee , Choi Okhee , Kang Yongsung , Kim Hongsup , Goo Eunhye , Ma Jun , Nagamatsu Tomohisa , Moon Jae Sun , Hwang Ingyu 
Published: May 2009

ABSTRACT

Burkholderia glumae
produces toxoflavin, a phytotoxin with a broad host range, which is a key virulence factor in bacterial rice grain rot. Based on genetic analysis, we previously reported that ToxR, a LysR-type regulator, activates both the
toxABCDE
(toxoflavin biosynthesis genes) and
toxFGHI
(toxoflavin transporter genes) operons in the presence of toxoflavin as a coinducer. Quorum sensing regulates the expression of the transcriptional activator ToxJ that is required for
tox
gene expression. Here, we used gel mobility shift and DNase I protection analyses to demonstrate that both ToxR and ToxJ bind simultaneously to the regulatory regions of both
tox
operons. ToxR and ToxJ both bound to the
toxA
and
toxF
regulatory regions, and the sequences for the binding of ToxR to the regulatory regions of both
tox
operons possessed T-N
11
-A motifs. Following random mutagenesis of
toxR
, 10 ToxR mutants were isolated. We constructed a reporter strain, S6K34 (
toxR
′
A
′::Ω
toxF
::Tn
3
-
gusA34
) to evaluate which amino acid residues are important for ToxR activity. Several single amino acid substitutions identified residues that might be important for ToxR binding to DNA and toxoflavin binding. When various toxoflavin derivatives were tested to determine whether toxoflavin is a specific coinducer of ToxR in the S6K34 strain, ToxR, together with toxoflavin, conferred
toxF
expression, whereas 4,8-dihydrotoxoflavin did so only slightly. With these results, we have demonstrated biochemically that
B. glumae
cells control toxoflavin production tightly by the requirement of both ToxJ and toxoflavin as coinducers of ToxR.
Staphylococcal pyrogenic toxins in infant urine samples: a possible marker of transient bacteraemia
Authors: Harrison L M , Morris J A , Lauder R M , Telford D R 
Published: May 2009

Aim:To screen infant urine for staphylococcal pyrogenic toxins as a possible marker for a toxigenic, transient bacteraemia.Methods:Nasopharyngeal swabs, skin swabs, stool and urine samples were collected from 30 infants at 2 weeks, 10 weeks and 7 months of age when the infants were healthy, and from infants of 7 months of age when they had a cold. Samples were cultured andStaphylococcusaureusisolates identified. Isolates were tested for the production of staphylococcal enterotoxin B (SEB), staphylococcal enterotoxin C (SEC) and toxic shock syndrome toxin (TSST-1). Urine samples were analysed for the presence of these toxins by ELISA.Results:Nasopharyngeal carriage ofS aureusdecreased with age from 50% at 2 weeks of age to 13% in healthy infants at 7 months of age. Carriage was increased in infants over 7 months of age with a cold (36%). Stool carriage remained constant (37–40%) in healthy infants but increased significantly in infants over 7 months of age with a cold (82%). 13.9% of the isolates produced SEB, 16.7% produced SEC and 18% produced TSST-1. Some isolates produced more than one toxin. 43% of infants were colonised at some time with a toxigenicS aureusstrain.S aureustoxins were detected in 9/101 urine samples. The proportion of positive samples was increased with infection and at 10 weeks of age.Conclusions:Infants are exposed early in life toS aureuspyrogenic toxins, which can be detected in infant urine samples. Age and infection affect the proportion of positive samples. The pattern of results can be explained by episodes of transient bacteraemia.
High prevalence of autoantibodies in hepatitis A infection: the impact on laboratory profiles
Authors: Moon H W , Noh J K , Hur M , Yun Y M , Lee C H , Kwon S Y 
Published: May 2009

Aims:In the absence of IgM antibodies against hepatitis A virus (HAV), HAV infections can be regarded as autoimmune hepatitis when they show positive autoantibodies by indirect immunofluorescence and lack other viral markers. The aim of this study was to evaluate the prevalence, titres and impact of autoantibodies in Korean patients with HAV infection.Methods:The study involved a retrospective review of the electronic medical records of 73 patients with HAV at Konkuk University Hospital from August 2005 to September 2008. The presence and pattern of anti-nuclear antibody, anti-smooth muscle antibody, anti-mitochondrial antibody and anti-liver/kidney microsomal antibody were assessed by indirect immunofluorescence on Hep-2 cells and mouse/kidney sections.Results:Of the 73 patients with hepatitis A, 65 (89.0%) showed positive indirect immunofluorescence tests. Of note, most of the positive tests (95.5%) showed a cytoplasmic pattern with filamentous staining of cytoplasmic fibres. There was no significant difference between groups in age or sex. In patients positive for autoantibodies, alanine aminotransferase and leucocyte count were significantly higher, while the increase in globulin was not statistically significant. In terms of titres, globulin was significantly higher in patients with ⩾1:160 titres than in those with ⩽1:80 titres (mean (SD) 3.4 (0.5) versus 2.8 (0.4) g/dl, respectively; p = 0.000).Conclusions:The study demonstrated a high prevalence of anticytoplasmic autoantibodies in patients with acute hepatitis A. These data would be useful to aid interpretation of indirect immunofluorescence testing in patients with acute hepatitis, especially in areas with a high prevalence of HAV.
Automobile industry occupations and bladder cancer: a population-based case-control study in southeastern Michigan, USA
Authors: Kobrosly R W , Meliker J R , Nriagu J O 
Published: May 2009

Objectives:To determine whether employees in the automobile industry in Michigan are at elevated risk of urinary bladder cancer.Methods:The authors conducted a population-based case-control study including 418 cases and 571 controls. History of employment within the automobile industry was coded according to the US Census Bureau Index of Occupations. Logistic regression analyses were adjusted for age at interview, cigarette smoking status, and highest education level, and used to assess associations between bladder cancer and (1) ever working in particular occupations within the automobile industry; and (2) usual occupation — defined as occupation of longest duration for each subject.Results:Ever having worked in the automobile industry and usual employment within the industry exhibited elevated non-significant risks for bladder cancer among assembly line workers, painters and foremen. A higher risk was seen for those who worked for 20 or more years on the assembly line (OR  =  2.10, 95% CI 1.15 to 3.80). Statistical interaction between usual employment on the assembly line and smoking status (>5 pack-years) was demonstrated (OR  =  6.19, 95% CI 2.69 to 14.24).Conclusions:Among workers on the assembly line for at least 20 years, we observed an approximately twofold risk for bladder cancer. Heavy smokers working on the assembly line experience a sixfold risk for bladder cancer. Further research is necessary to verify this finding, identify the exposures that might be contributing to bladder cancer on the assembly line, and examine whether those exposures continue to persist in today’s workplace.