bluuebunny/crossref_metadata_2025 huggingface dataset:
Accumulation of Non-Superoxide Anion Reactive Oxygen Species Mediates Nitrogen-Limited Alcoholic Fermentation by
Saccharomyces cerevisiae
Authors: Mendes-Ferreira Ana , Sampaio-Marques Belém , Barbosa Catarina , Rodrigues Fernando , Costa Vítor , Mendes-Faia Arlete , Ludovico Paula , Leão Cecília
Published: October 2010

Throughout alcoholic fermentation, nitrogen depletion is one of the most important environmental stresses that can negatively affect the yeast metabolic activity and ultimately leads to fermentation arrest. Thus, the identification of the underlying effects and biomarkers of nitrogen limitation is valuable for controlling, and therefore optimizing, alcoholic fermentation. In this study, reactive oxygen species (ROS), plasma membrane integrity, and cell cycle were evaluated in a wine strain of
Saccharomyces cerevisiae
during alcoholic fermentation in nitrogen-limiting medium under anaerobic conditions. The results indicated that nitrogen limitation leads to an increase in ROS and that the superoxide anion is a minor component of the ROS, but there is increased activity of both Sod2p and Cta1p. Associated with these effects was a decrease in plasma membrane integrity and a persistent cell cycle arrest at G
0
/G
1
phases. Moreover, under these conditions it appears that autophagy, evaluated by
ATG8
expression, is induced, suggesting that this mechanism is essential for cell survival but does not prevent the cell cycle arrest observed in slow fermentation. Conversely, nitrogen refeeding allowed cells to reenter cell cycle by decreasing ROS generation and autophagy. Altogether, the results provide new insights on the understanding of wine fermentations under nitrogen-limiting conditions and further indicate that ROS accumulation, evaluated by the MitoTracker Red dye CM-H
2
XRos, and plasma membrane integrity could be useful as predictive markers of fermentation problems.
Determination of the Effects of Medium Composition on the Monochloramine Disinfection Kinetics of
Nitrosomonas europaea
by the Propidium Monoazide Quantitative PCR and Live/Dead BacLight Methods
Authors: Wahman David G. , Schrantz Karen A. , Pressman Jonathan G.
Published: October 2010

Various medium compositions (phosphate, 1 to 50 mM; ionic strength, 2.8 to 150 meq/liter) significantly affected
Nitrosomonas europaea
monochloramine disinfection kinetics, as determined by the Live/Dead BacLight (LD) and propidium monoazide quantitative PCR (PMA-qPCR) methods (lag coefficient, 37 to 490 [LD] and 91 to 490 [PMA-qPCR] mg·min/liter; Chick-Watson rate constant, 4.0 × 10
−3
to 9.3 × 10
−3
[LD] and 1.6 × 10
−3
to 9.6 × 10
−3
[PMA-qPCR] liter/mg·min). Two competing effects may account for the variation in disinfection kinetic parameters: (i) increasing kinetics (disinfection rate constant [
k
] increased, lag coefficient [
b
] decreased) with increasing phosphate concentration and (ii) decreasing kinetics (
k
decreased,
b
increased) with increasing ionic strength. The results support development of a standard medium for evaluating disinfection kinetics in drinking water.
Characterization of the Protocatechuate 4,5-Cleavage Pathway Operon in
Comamonas
sp. Strain E6 and Discovery of a Novel Pathway Gene
Authors: Kamimura Naofumi , Aoyama Taichi , Yoshida Rieko , Takahashi Kenji , Kasai Daisuke , Abe Tomokuni , Mase Kohei , Katayama Yoshihiro , Fukuda Masao , Masai Eiji
Published: October 2010

The protocatechuate (PCA) 4,5-cleavage (PCA45) pathway is the essential catabolic route for the degradation of various aromatic acids in the genus
Comamonas
. All of the PCA45 pathway genes,
orf1-pmdKEFDABC
, as well as another PCA 4,5-dioxygenase gene,
pmdA
II
B
II
, were isolated from a phthalate-degrading bacterium,
Comamonas
sp. strain E6. Disruption of
pmdB
and
pmdD
in E6, which code for the β subunit of PCA 4,5-dioxygenase and 2-pyrone-4,6-dicarboxylate (PDC) hydrolase, respectively, resulted in a growth defect on PCA, indicating that these genes are essential for the growth of E6 on PCA. On the other hand, inactivation of
pmdB
II
did not affect the growth of E6 on PCA. Disruption of
pmdK
, which is related to a 4-hydroxybenzoate/PCA transporter of
Pseudomonas putida
, resulted in growth retardation on PCA. The insertional inactivation of
orf1
in E6, whose deduced amino acid sequence has no similarity with proteins of known function, led to the complete loss of growth on PCA and the accumulation of PDC and 4-oxalomesaconate (OMA) from PCA. These results indicated the involvement of
orf1
in the PCA45 pathway, and this gene, designated
pmdU
, was suggested to code for OMA tautomerase. Reverse transcription-PCR analysis suggested that the
pmdUKEFDABC
genes constitute an operon. The transcription start site of the
pmd
operon was mapped at 167 nucleotides upstream of the initiation codon of
pmdU
. The
pmd
promoter activity was enhanced 20-fold when the cells were grown in the presence of PCA. Inducers of the
pmd
operon were found to be PCA and PDC, but PDC was the more effective inducer.
Does Aqueous Fullerene Inhibit the Growth of
Saccharomyces cerevisiae
or
Escherichia coli
?
Authors: Hadduck Alex N. , Hindagolla Vihangi , Contreras Alison E. , Li Qilin , Bakalinsky Alan T.
Published: October 2010

Studies reporting on potentially toxic interactions between aqueous fullerene nanoparticles (nC
60
) and microorganisms have been contradictory. When known confounding factors were avoided, growth yields of
Saccharomyces cerevisiae
and
Escherichia coli
cultured in the presence and absence of independently prepared lots of underivatized nC
60
were found not to be significantly different.
Hal4 and Hal5 Protein Kinases Are Required for General Control of Carbon and Nitrogen Uptake and Metabolism
Authors: Pérez-Valle Jorge , Rothe Jessica , Primo Cecilia , Martínez Pastor Mar , Ariño Joaquin , Pascual-Ahuir Amparo , Mulet José Miguel , Serrano Ramón , Yenush Lynne
Published: October 2010

The yeast protein kinases Sat4/Hal4 and Hal5 are required for the plasma membrane stability of the K
+
transporter Trk1 and some amino acid and glucose permeases. The transcriptomic analysis presented here indicates alterations in the general control of the metabolism of both nitrogen and carbon. Accordingly, we observed reduced uptake of methionine and leucine in the
hal4 hal5
mutant. This decrease correlates with activation of the Gcn2-Gcn4 pathway, as measured by expression of the
lacZ
gene under the control of the
GCN4
promoter. However, with the exception of methionine biosynthetic genes, few amino acid biosynthetic genes are induced in the
hal4 hal5
mutant, whereas several genes involved in amino acid catabolism are repressed. Concerning glucose metabolism, we found that this mutant exhibits derepression of respiratory genes in the presence of glucose, leading to an increased activity of mitochondrial enzymes, as measured by succinate dehydrogenase (SDH) activity. In addition, the reduced glucose consumption in the
hal4 hal5
mutant correlates with a more acidic intracellular pH and with low activity of the plasma membrane H
+
-ATPase. As a compensatory mechanism for the low glycolytic rate, the
hal4 hal5
mutant overexpresses the
HXT4
high-affinity glucose transporter and the hexokinase genes. These results indicate that the
hal4 hal5
mutant presents defects in the general control of nitrogen and carbon metabolism, which correlate with reduced transport of amino acids and glucose, respectively. A more acidic intracellular pH may contribute to some defects of this mutant.
A Mutant Defective in Sexual Development Produces Aseptate Ascogonia
Authors: Bloemendal Sandra , Lord Kathryn M. , Rech Christine , Hoff Birgit , Engh Ines , Read Nick D. , Kück Ulrich
Published: October 2010

The transition from the vegetative to the sexual cycle in filamentous ascomycetes is initiated with the formation of ascogonia. Here, we describe a novel type of sterile mutant from
Sordaria macrospora
with a defect in ascogonial septum formation. This mutant, named pro22, produces only small, defective protoperithecia and carries a point mutation in a gene encoding a protein that is highly conserved throughout eukaryotes. Sequence analyses revealed three putative transmembrane domains and a C-terminal domain of unknown function. Live-cell imaging showed that PRO22 is predominantly localized in the dynamic tubular and vesicular vacuolar network of the peripheral colony region close to growing hyphal tips and in ascogonia; it is absent from the large spherical vacuoles in the vegetative hyphae of the subperipheral region of the colony. This points to a specific role of PRO22 in the tubular and vesicular vacuolar network, and the loss of intercalary septation in ascogonia suggests that PRO22 functions during the initiation of sexual development.
Functional Characterization of a New Member of the Cdk9 Family in Aspergillus nidulans
Authors: Bathe Friederike , Kempf Claudia , Osmani Stephen A. , Osmani Aysha H. , Hettinger Sabrina , Wohlmann Elke , Fischer Reinhard
Published: October 2010

Cdk9-like kinases in complex with T-type cyclins are essential components of the eukaryotic transcription elongation machinery. The full spectrum of Cdk9/cyclin T targets, as well as the specific consequences of phosphorylations, is still largely undefined. We identify and characterize here a Cdk9 kinase (PtkA) in the filamentous ascomycete
Aspergillus nidulans
. Deletion of
ptkA
had a lethal effect in later stages of vegetative growth and completely impeded asexual development. Overexpression of
ptkA
affected directionality of polarized growth and the initiation of new branching sites. A green fluorescent protein-tagged PtkA version localized inside the nucleus during interphase, supporting a role of PtkA in transcription elongation, as observed in other organisms. We also identified a putative cyclin T homolog, PchA, in the
A. nidulans
genome and confirmed its interaction with PtkA
in vivo
. Surprisingly, the Pcl-like cyclin PclA, previously described to be involved in asexual development, was also found to interact with PtkA, indicating a possible role of PtkA in linking transcriptional activity with development and/or morphogenesis in
A. nidulans
. This is the first report of a Cdk9 kinase interacting with a Pcl-like cyclin, revealing interesting new aspects about the involvement of this Cdk-subfamily in differential gene expression.
Preclinical Evaluation of the Pht Proteins as Potential Cross-Protective Pneumococcal Vaccine Antigens
Authors: Godfroid Fabrice , Hermand Philippe , Verlant Vincent , Denoël Philippe , Poolman Jan T.
Published: October 2010

Current pneumococcal vaccines are composed of capsular polysaccharides (PS) of various serotypes, either as free PS or as protein-PS conjugates. The use of pneumococcus protein antigens that are able to afford protection across the majority of serotypes is envisaged as a relevant alternative and/or complement to the polysaccharides. In this context, based on several studies, the Pht protein family emerged as relevant vaccine candidates. The purpose of the present study was to evaluate the Pht protein family in several preclinical mouse models. Immunization with these antigens was compared with immunization with other pneumococcal antigens, such as CbpA, PspA, and PsaA. In a nasopharyngeal colonization model and in a lung colonization model, the Phts were found to be superior to the other candidates in terms of efficacy of protection and serotype coverage. Likewise, vaccination with PhtD allowed higher animal survival rates after lethal intranasal challenge. Finally, a passive transfer model in which natural anti-PhtD human antibodies were transferred into mice demonstrated significant protection against lethal intranasal challenge. This indicates that natural anti-PhtD human antibodies are able to protect against pneumococcal infection. Our findings, together with the serotype-independent occurrence of the Phts, designate this protein family as valid candidate antigens to be incorporated in protein-based pneumococcal vaccines.
Nontypeable
Haemophilus influenzae
Initiates Formation of Neutrophil Extracellular Traps
Authors: Juneau Richard A. , Pang Bing , Weimer Kristin E. D. , Armbruster Chelsie E. , Swords W. Edward
Published: October 2010

Nontypeable
Haemophilus influenzae
(NTHI) is a leading cause of otitis media infections, which are often chronic and/or recurrent in nature. NTHI and other bacterial species persist
in vivo
within biofilms during otitis media and other persistent infections. These biofilms have a significant host component that includes neutrophil extracellular traps (NETs). These NETs do not mediate clearance of NTHI, which survives within NET structures by means of specific subpopulations of lipooligosaccharides on the bacterial surface that are determinants of biofilm formation
in vitro
. In this study, the ability of NTHI and NTHI components to initiate NET formation was examined using an
in vitro
model system. Both viable and nonviable NTHI strains were shown to promote NET formation, as did preparations of bacterial DNA, outer membrane proteins, and lipooligosaccharide (endotoxin). However, only endotoxin from a parental strain of NTHI exhibited equivalent potency in NET formation to that of NTHI. Additional studies showed that NTHI entrapped within NET structures is resistant to both extracellular killing within NETs and phagocytic killing by incoming neutrophils, due to oligosaccharide moieties within the lipooligosaccharides. Thus, we concluded that NTHI elicits NET formation by means of multiple pathogen-associated molecular patterns (most notably endotoxin) and is highly resistant to killing within NET structures. These data support the conclusion that, for NTHI, formation of NET structures may be a persistence determinant by providing a niche within the middle-ear chamber.
BglJ-RcsB Heterodimers Relieve Repression of theEscherichia coli bglOperon by H-NS
Authors: Venkatesh G. Raja , Kembou Koungni Frant Carlot , Paukner Andreas , Stratmann Thomas , Blissenbach Birgit , Schnetz Karin
Published: October 2010

RcsB is the response regulator of the complex Rcs two-component system, which senses perturbations in the outer membrane and peptidoglycan layer. BglJ is a transcriptional regulator whose constitutive expression causes activation of the H-NS- and StpA-repressedbgl(aryl-β,d-glucoside) operon inEscherichia coli. RcsB and BglJ both belong to the LuxR-type family of transcriptional regulators with a characteristic C-terminal DNA-binding domain. Here, we show that BglJ and RcsB interact and form heterodimers that presumably bind upstream of thebglpromoter, as suggested by mutation of a sequence motif related to the consensus sequence for RcsA-RcsB heterodimers. Heterodimerization of BglJ-RcsB and relief of H-NS-mediated repression ofbglby BglJ-RcsB are apparently independent of RcsB phosphorylation. In addition, we show that LeuO, a pleiotropic LysR-type transcriptional regulator, likewise binds to thebglupstream regulatory region and relieves repression ofbglindependently of BglJ-RcsB. Thus, LeuO can affectbgldirectly, as shown here, and indirectly by activating the H-NS-repressedyjjQ-bglJoperon, as shown previously. Taken together, heterodimer formation of RcsB and BglJ expands the role of the Rcs two-component system and the network of regulators affecting thebglpromoter.
Genomic Island 2 Is an Unstable Genetic Element Contributing toBrucellaLipopolysaccharide Spontaneous Smooth-to-Rough Dissociation
Authors: Mancilla Marcos , López-Goñi Ignacio , Moriyón Ignacio , Zárraga Ana María
Published: October 2010

Brucellais a Gram-negative bacterium that causes a worldwide-distributed zoonosis. The genus includes smooth (S) and rough (R) species that differ in the presence or absence, respectively, of the O-polysaccharide of lipopolysaccharide. In S brucellae, the O-polysaccharide is a critical diagnostic antigen and a virulence determinant. However, S brucellae spontaneously dissociate into R forms, a problem in antigen and S vaccine production. Spontaneous R mutants ofBrucella abortus,Brucella melitensis, andBrucella suiscarried the chromosomal scar corresponding to genomic island 2 (GI-2) excision, an event causing the loss of thewboAandwboBO-polysaccharide genes, and the predicted excised circular intermediate was identified inB. abortus,B. melitensis, andB. suiscultures. Moreover, disruption of a putative phage integrase gene inB. abortusGI-2 caused a reduction in O-polysaccharide loss rates under conditions promoting S-R dissociation. However, spontaneous R mutants not carrying the GI-2 scar were also detected. These results demonstrate that the phage integrase-related GI-2 excision is a cause of S-R brucella dissociation and that other undescribed mechanisms must also be involved. In the RBrucellaspecies, previous works have shown thatBrucella ovisbut notBrucella canislacks GI-2, and a chromosomal scar identical to those in R mutants was observed. These results suggest that the phage integrase-promoted GI-2 excision played a role inB. ovisspeciation and are consistent with other evidence, suggesting that this species andB. canishave emerged as two independent lineages.
Biochemical Characterization of Individual Components of the
Allochromatium vinosum
DsrMKJOP Transmembrane Complex Aids Understanding of Complex Function
In Vivo
Authors: Grein Fabian , Pereira Inês A. C. , Dahl Christiane
Published: October 2010

The DsrMKJOP transmembrane complex has a most important function in dissimilatory sulfur metabolism and consists of cytoplasmic, periplasmic, and membrane integral proteins carrying FeS centers and
b
- and
c
-type cytochromes as cofactors. In this study, the complex was isolated from the purple sulfur bacterium
Allochromatium vinosum
and individual components were characterized as recombinant proteins. The two integral membrane proteins DsrM and DsrP were successfully produced in
Escherichia coli
C43(DE3) and C41(DE3), respectively. DsrM was identified as a diheme cytochrome
b
, and the two hemes were found to be in low-spin state. Their midpoint redox potentials were determined to be +60 and +110 mV. Although no hemes were predicted for DsrP, it was also clearly identified as a
b
-type cytochrome. To the best of our knowledge, this is the first time that heme binding has been experimentally proven for a member of the NrfD protein family. Both cytochromes were partly reduced after addition of a menaquinol analogue, suggesting interaction with quinones
in vivo
. DsrO and DsrK were both experimentally proven to be FeS-containing proteins. In addition, DsrK was shown to be membrane associated, and we propose a monotopic membrane anchoring for this protein. Coelution assays provide support for the proposed interaction of DsrK with the soluble cytoplasmic protein DsrC, which might be its substrate. A model for the function of DsrMKJOP in the purple sulfur bacterium
A. vinosum
is presented.
Expression of the
Streptomyces coelicolor
SoxR Regulon Is Intimately Linked with Actinorhodin Production
Authors: Dela Cruz Rica , Gao Yang , Penumetcha Sahitya , Sheplock Rebecca , Weng Katherine , Chander Monica
Published: October 2010

The [2Fe-2S]-containing transcription factor SoxR is conserved in diverse bacteria. SoxR is traditionally known as the regulator of a global oxidative stress response in
Escherichia coli
, but recent studies suggest that this function may be restricted to enteric bacteria. In the vast majority of nonenterics, SoxR is predicted to mediate a response to endogenously produced redox-active metabolites. We have examined the regulation and function of the SoxR regulon in the model antibiotic-producing filamentous bacterium
Streptomyces coelicolor
. Unlike the
E. coli soxR
deletion mutant, the
S. coelicolor
equivalent is not hypersensitive to oxidants, indicating that SoxR does not potentiate antioxidant defense in the latter. SoxR regulates five genes in
S. coelicolor
, including those encoding a putative ABC transporter, two oxidoreductases, a monooxygenase, and a possible NAD-dependent epimerase/dehydratase. Expression of these genes depends on the production of the benzochromanequinone antibiotic actinorhodin and requires intact [2Fe-2S] clusters in SoxR. These data indicate that actinorhodin, or a redox-active precursor, modulates SoxR activity in
S. coelicolor
to stimulate the production of a membrane transporter and proteins with homology to actinorhodin-tailoring enzymes. While the role of SoxR in
S. coelicolor
remains under investigation, these studies support the notion that SoxR has been adapted to perform distinct physiological functions to serve the needs of organisms that occupy different ecological niches and face different environmental challenges.
DosS Responds to a Reduced Electron Transport System To Induce the
Mycobacterium tuberculosis
DosR Regulon
Authors: Honaker Ryan W. , Dhiman Rakesh K. , Narayanasamy Prabagaran , Crick Dean C. , Voskuil Martin I.
Published: October 2010

The DosR regulon in
Mycobacterium tuberculosis
is involved in respiration-limiting conditions, its induction is controlled by two histidine kinases, DosS and DosT, and recent experimental evidence indicates DosS senses either molecular oxygen or a redox change. Under aerobic conditions, induction of the DosR regulon by DosS, but not DosT, was observed after the addition of ascorbate, a powerful cytochrome
c
reductant, demonstrating that DosS responds to a redox signal even in the presence of high oxygen tension. During hypoxic conditions, regulon induction was attenuated by treatment with compounds that occluded electron flow into the menaquinone pool or decreased the size of the menaquinone pool itself. Increased regulon expression during hypoxia was observed when exogenous menaquinone was added, demonstrating that the menaquinone pool is a limiting factor in regulon induction. Taken together, these data demonstrate that a reduced menaquinone pool directly or indirectly triggers induction of the DosR regulon via DosS. Biochemical analysis of menaquinones upon entry into hypoxic/anaerobic conditions demonstrated the disappearance of the unsaturated species and low-level maintenance of the mono-saturated menaquinone. Relative to the unsaturated form, an analog of the saturated form is better able to induce signaling via DosS and rescue inhibition of menaquinone synthesis and is less toxic. The menaquinone pool is central to the electron transport system (ETS) and therefore provides a mechanistic link between the respiratory state of the bacilli and DosS signaling. Although this report demonstrates that DosS responds to a reduced ETS, it does not rule out a role for oxygen in silencing signaling.
Role of Porins in Iron Uptake byMycobacterium smegmatis
Authors: Jones Christopher M. , Niederweis Michael
Published: October 2010

Many bacteria rely on siderophores to extract iron from the environment. However, acquisition of iron-loaded siderophores is dependent on high-affinity uptake systems that are not produced under high-iron conditions. The fact that bacteria are able to maintain iron homeostasis in the absence of siderophores indicates that alternative iron acquisition systems exist. It has been speculated that such low-affinity uptake of iron in Gram-negative bacteria includes diffusion of iron ions or chelates across the outer membrane through porins. The outer membrane of the saprophyticMycobacterium smegmatiscontains the Msp family of porins, which enable the diffusion of small and hydrophilic solutes, such as monosaccharides, amino acids, and phosphate. However, it is unknown how cations cross the outer membrane of mycobacteria. Here, we show that the Msp porins ofM. smegmatisare involved in the acquisition of soluble iron under high-iron conditions. Uptake of ferric ions by a triple porin mutant was reduced compared to wild-type (wt)M. smegmatis. An intracellular iron reporter indicated that derepression of iron-responsive genes occurs at higher iron concentrations in the porin mutant. This was consistent with the finding that the porin mutant produced more siderophores under low-iron conditions than wtM. smegmatis. In contrast, uptake of the exochelin MS, the main siderophore ofM. smegmatis, was not affected by the lack of porins, indicating that a specific outer membrane siderophore receptor exists. These results provide, to our knowledge, the first experimental evidence that general porins are indeed the outer membrane conduit of low-affinity iron acquisition systems in bacteria.
The Putative Assembly Factor CcoH Is Stably Associated with the
cbb
3
-Type Cytochrome Oxidase
Authors: Pawlik Grzegorz , Kulajta Carmen , Sachelaru Ilie , Schröder Sebastian , Waidner Barbara , Hellwig Petra , Daldal Fevzi , Koch Hans-Georg
Published: October 2010

Cytochrome oxidases are perfect model substrates for analyzing the assembly of multisubunit complexes because the need for cofactor incorporation adds an additional level of complexity to their assembly.
cbb
3
-type cytochrome
c
oxidases (
cbb
3
-Cox) consist of the catalytic subunit CcoN, the membrane-bound
c
-type cytochrome subunits CcoO and CcoP, and the CcoQ subunit, which is required for
cbb
3
-Cox stability. Biogenesis of
cbb
3
-Cox proceeds via CcoQP and CcoNO subcomplexes, which assemble into the active
cbb
3
-Cox. Most bacteria expressing
cbb
3
-Cox also contain the
ccoGHIS
genes, which encode putative
cbb
3
-Cox assembly factors. Their exact function, however, has remained unknown. Here we analyzed the role of CcoH in
cbb
3
-Cox assembly and showed that CcoH is a single spanning-membrane protein with an N-terminus-out-C-terminus-in (N
out
-C
in
) topology. In its absence, neither the fully assembled
cbb
3
-Cox nor the CcoQP or CcoNO subcomplex was detectable. By chemical cross-linking, we demonstrated that CcoH binds primarily via its transmembrane domain to the CcoP subunit of
cbb
3
-Cox. A second hydrophobic stretch, which is located at the C terminus of CcoH, appears not to be required for contacting CcoP, but deleting it prevents the formation of the active
cbb
3
-Cox. This suggests that the second hydrophobic domain is required for merging the CcoNO and CcoPQ subcomplexes into the active
cbb
3
-Cox. Surprisingly, CcoH does not seem to interact only transiently with the
cbb
3
-Cox but appears to stay tightly associated with the active, fully assembled complex. Thus, CcoH behaves more like a bona fide subunit of the
cbb
3
-Cox than an assembly factor
per se
.
Instability ofackA(Acetate Kinase) Mutations and Their Effects on Acetyl Phosphate and ATP Amounts inStreptococcus pneumoniaeD39
Authors: Ramos-Montañez Smirla , Kazmierczak Krystyna M. , Hentchel Kristy L. , Winkler Malcolm E.
Published: October 2010

Acetyl phosphate (AcP) is a small-molecule metabolite that can act as a phosphoryl group donor for response regulators of two-component systems (TCSs). The serious human respiratory pathogenStreptococcus pneumoniae(pneumococcus) synthesizes AcP by the conventional pathway involving phosphotransacetylase and acetate kinase, encoded byptaandackA, respectively. In addition, pneumococcus synthesizes copious amounts of AcP and hydrogen peroxide (H2O2) by pyruvate oxidase, which is encoded byspxB. To assess possible roles of AcP in pneumococcal TCS regulation and metabolism, we constructed strains with combinations ofspxB,pta, andackAmutations and determined their effects on ATP, AcP, and H2O2production. Unexpectedly, ΔackAmutants were unstable and readily accumulated primary suppressor mutations in spxBor its positive regulator,spxR, thereby reducing H2O2and AcP levels, and secondary capsule mutations incps2Eorcps2C. ΔackAΔspxBmutants contained half the cellular amount of ATP as a ΔspxBorspxB+strain. Acetate addition and anaerobic growth experiments suggested decreased ATP, rather than increased AcP, as a reason that ΔackAmutants accumulatedspxBorspxRsuppressors, although experimental manipulation of the AcP amount was limited. This finding and other considerations suggest that coping with endogenously produced H2O2may require energy. Starting with a ΔspxBmutant, we constructed Δpta, ΔackA, and ΔptaΔackAmutants. Epistasis and microarray experiment results were consistent with a role for the SpxB-Pta-AckA pathway in expression of the regulons controlled by the WalRKSpn, CiaRHSpn, and LiaSRSpnTCSs involved in sensing cell wall status. However, AcP likely does not play a physiological role in TCS sensing inS. pneumoniae.
Genome of
Helicobacter pylori
Strain 908
Authors: Devi Singamaneni Haritha , Taylor Todd D. , Avasthi Tiruvayipati Suma , Kondo Shinji , Suzuki Yutaka , Megraud Francis , Ahmed Niyaz
Published: October 2010

Helicobacter pylori
is a genetically diverse and coevolved pathogen inhabiting human gastric niches and leading to a spectrum of gastric diseases in susceptible populations. We describe the genome sequence of
H. pylori
908, which was originally isolated from an African patient living in France who suffered with recrudescent duodenal ulcer disease. The strain was found to be phylogenetically related to
H. pylori
J99, and its comparative analysis revealed several specific genome features and novel insertion-deletion and substitution events. The genome sequence revealed several strain-specific deletions and/or gain of genes exclusively present in HP908 compared with different sequenced genomes already available in the public domain. Comparative and functional genomics of HP908 and its subclones will be important in understanding genomic plasticity and the capacity to colonize and persist in a changing host environment.
Genome Sequence of the Biocontrol Agent
Pantoea vagans
Strain C9-1
Authors: Smits Theo H. M. , Rezzonico Fabio , Kamber Tim , Goesmann Alexander , Ishimaru Carol A. , Stockwell Virginia O. , Frey Jürg E. , Duffy Brion
Published: October 2010

Pantoea vagans
is a Gram-negative enterobacterial plant epiphyte of a broad range of plants. Here we report the 4.89-Mb genome sequence of
P. vagans
strain C9-1 (formerly
Pantoea agglomerans
), which is commercially registered for biological control of fire blight, a disease of pear and apple trees caused by
Erwinia amylovora.
Genome Sequence of the Obligate Methanotroph
Methylosinus trichosporium
Strain OB3b
Authors: Stein Lisa Y. , Yoon Sukhwan , Semrau Jeremy D. , DiSpirito Alan A. , Crombie Andrew , Murrell J. Colin , Vuilleumier Stéphane , Kalyuzhnaya Marina G. , Op den Camp Huub J. M. , Bringel Françoise , Bruce D. , Cheng J.-F. , Copeland A. , Goodwin Lynne , Han Shunsheng , Hauser Loren , Jetten Mike S. M. , Lajus Aurélie , Land M. L. , Lapidus A. , Lucas S. , Médigue Claudine , Pitluck S. , Woyke Tanja , Zeytun Ahmet , Klotz Martin G.
Published: October 2010

Methylosinus trichosporium
OB3b (for “oddball” strain 3b) is an obligate aerobic methane-oxidizing alphaproteobacterium that was originally isolated in 1970 by Roger Whittenbury and colleagues. This strain has since been used extensively to elucidate the structure and function of several key enzymes of methane oxidation, including both particulate and soluble methane monooxygenase (sMMO) and the extracellular copper chelator methanobactin. In particular, the catalytic properties of soluble methane monooxygenase from
M. trichosporium
OB3b have been well characterized in context with biodegradation of recalcitrant hydrocarbons, such as trichloroethylene. The sequence of the
M. trichosporium
OB3b genome is the first reported from a member of the
Methylocystaceae
family in the order
Rhizobiales
.
Genome Sequence of
Leuconostoc argentinum
KCTC 3773
Authors: Nam Seong-Hyeuk , Choi Sang-Haeng , Kang Aram , Kim Dong-Wook , Kim Ryong Nam , Kim Aeri , Park Hong-Seog
Published: October 2010

Leuconostoc argentinum
is one of the most prevalent lactic acid bacteria present during the manufacturing process of kimchi, the best-known traditional Korean dish. Here, we present the draft genome sequence of type strain KCTC 3773 of
Leuconostoc argentinum
(1,720,683 bp, with a G+C content of 42.9%), which consists of 98 large contigs (>100 bp in size).
Profit from prevention
Authors: Jevring Caroline
Published: October 2010

Today's veterinary surgeon should measure professional success not by the number of 'interesting cases' or conditions diagnosed and treated, but by the number of animals on the practice records that are enjoying perfect health, says CAROLINE JEVRING. Here, she discusses the value of preventive health care in small animal practice
Diagnosis and management of glaucoma
Authors: Renwick Peter
Published: October 2010

GLAUCOMA is one of the most common causes of blindness seen in small animal practice. It can be considered to be a complex of pathological events which arises as a result of prolonged elevation of the intraocular pressure. The optic nerve head and retina are particularly sensitive to elevated intraocular pressure and damage to these neural tissues may rapidly become irreversible. In addition, pain is often a significant feature of the condition and can be difficult to control. It is therefore of utmost importance that glaucoma is diagnosed in its early stages and that appropriate therapy is instituted if blindness and unnecessary discomfort are to be avoided.
Handling farmed deer
Authors: Fletcher John
Published: October 2010

DEER farming has been developing steadily in Britain since the early 1970s and over the past few years the handling of farmed deer has become commonplace. Veterinary surgeons may become involved with deer on the farm, in quarantine premises, in semen and embryo collection centres and/or at the abattoir. This article is aimed primarily at those handling red deer. Fallow deer have a reputation for being more ‘flighty’, though with a correctly designed system they, too, can be handled smoothly and quickly.
Maintaining a vet‐rep rapport
Authors: Pepper David
Published: October 2010

ACCORDING to a recent survey of veterinary surgeons, an ideal company sales representative is one who has visited the practice for many years and gradually over that time has become a valued friend. The real measure of a good rep, the survey says, is that he or she doesn't try to sell to you…
Shoot to still
Authors: Ware Stephen
Published: October 2010

IN terms of their construction, dart guns could hardly be simpler. By contrast, the legal framework surrounding their use could hardly be more constraining.
Diagnosis of pyrexia of unknown origin
Authors: Bennett David
Published: October 2010

CASES referred to as fever or pyrexia of unknown origin often present a diagnostic challenge to practitioners. The main approach to diagnosis is to identify the reason for the pyrexia. Clinical signs are often non‐specific and may fluctuate in severity and alter with chronicity. Although it is theoretically desirable not to instigate any treatment before a full investigation has been carried out, in practice this is often difficult and a response to specific therapies can help in the diagnosis. If there are no localising signs, a series of simple screening tests is necessary to try to identify a septic, inflammatory or neoplastic focus.
The art and science of managing clients
Authors: Orpin Peter
Published: October 2010

THE scenic 1940s country practice described by James Herriot fulfilled the basic needs of the client. Friendly reassurance, good humour and simple solutions to every animal problem were all that was required. The vet was respected as a professional, and the art of veterinary practice was central to its success. In the 1990s, a variety of diagnostic imaging and surgical solutions (the science of practice) exists for the treatment of most conditions. However, it is still important not to neglect the art of practice.
Collection of tracheal respiratory secretions in the horse
Authors: Dixon Paddy
Published: October 2010

IN the investigation of equine pulmonary disease, ancillary diagnostic aids, such as tracheal respiratory secretion examinations, are performed, first, when clinical signs of pulmonary disease are inconclusive, to confirm if pulmonary disease is present, and, secondly, where there is overt pulmonary disease, to help establish the type of disease present. Additionally, in the case of pulmonary bacterial infections, respiratory secretion examinations can identify the type and sensitivity of the causal organisms.
Amputation of the ovine digit
Authors: Scott Phil
Published: October 2010

THE main indication for digit amputation in the sheep is septic pedal arthritis which occurs not uncommonly, affecting individual animals on intensively managed sheep units. It results in chronic severe lameness, reduced production and rapid loss of body condition. As such, it represents a serious welfare concern. Deep penetrating wounds of the sole or deep infections secondary to solar ulceration, meanwhile, are very uncommon in sheep, although infection may result from traumatic injury ‐ particularly if an object penetrates at the coronary band and is directed distally.
Diagnosis and treatment of the equine sarcoid
Authors: Knottenbelt Derek , Edwards Susan , Daniel Elizabeth
Published: October 2010

THE term ‘sarcoid’ is derived from the apparent sarcomatous appearance of the lesions as well as their tendency to recur following excision. The numbers of sarcoid (previously called 'warts') on any individual case, their character, distribution and extent, have a major bearing on the selection of the available treatment options. Clearly, the frustrations felt by many generations of veterinary surgeons have continued up to the present time; the equine sarcoid is probably the most common cutaneous reason for euthanasia and the loss to the equine industry is considerable. Horses in which there are few localised superficial lesions are usually amenable to any of the treatment options, although inadequate application will yield a poor result with a high rate of recurrence at the site and possible extension to other sites. No effective means of treating the malevolent type of sarcoid has yet been found and interfering with this particularly aggressive form merely exacerbates the signs.
Differential diagnosis of nasal disease in cats
Authors: Willoughby Kim , Coutts Alison
Published: October 2010

NASAL disease is one of the most commonly recognised problems in the cat. The likely aetiology can often be established from the history and clinical signs, although further investigation is required in more difficult cases. Diseases of the ear and throat will be discussed in an article in the next issue.
Differential diagnosis of recumbency in the neonatal calf
Authors: Scott Phil
Published: October 2010

Recumbency, commonly seen in calves less than one week old, poses a diagnostic challenge to the cattle practitioner. This article describes some of the reasons why a calf may be recumbent from birth (often related to trauma during second stage labour) or may subsequently become recumbent at some point following delivery. As with all clinical investigations, it is essential first to obtain an accurate history of the animal and to establish if it was ever able to raise itself and stand unaided. If so, when did the calf become recumbent? Other factors to be considered include the use of traction during parturition and whether the calf became hip‐locked during delivery.
If in doubt, ask
Authors: Lazarus Penny
Published: October 2010

CANVASSING client opinion can be a valuable exercise, giving the veterinary surgeon the opportunity to discover what clients think of the practice and how the services offered may be enhanced. This article considers the reasons for asking client opinion and the pros and cons of the methods available to you for gathering information.
Problems of extensive sheep farming systems
Authors: Winter Agnes
Published: October 2010

OF all the common farmed species in the UK, sheep are probably perceived by the non‐farming public as being the most 'naturally' kept, particularly when farmed extensively on vast areas such as the Pennines, the moors of Devon and Cornwall, the Lake District, the Scottish Highlands and the mountains of Wales. Hardy breeds such as the Herdwick, Swaledale, Welsh Mountain and Scottish Blackface have been developed over centuries to survive the harsh conditions commonly encountered during the long winter months. However, such a system of farming has many risks associated with it, in spite of its generally perceived 'green' image.
Partnership prospects
Authors: Pepper David
Published: October 2010

IT is a cliche of most professions that a partnership is like a marriage, but much more difficult to handle. It might be flattering to be asked to become involved in either relationship, but flattery is as poor a basis for deciding to say 'Yes, please' as it is to say 'I do'. This article hopes to make the selection of a partnership less haphazard than choosing a spouse. It is far better viewed as an arranged marriage, where an informed decision is taken rather than a gamble.
Taxation changes ‐ are you ready?
Authors: Houghton Peter
Published: October 2010

AS discussed in an earlier issue, the Government has begun a complete reform of the system for dealing with personal tax (Trickey 1994). The new system concentrates on two main areas ‐ self assessment and a current year basis of assessment. This article looks at the new current year basis of assessment and the significant impact the changes have on the way in which partnerships are taxed.
Investigation and management of recurrent colic in the horse
Authors: Schramme Michael
Published: October 2010

RECURRENT colic refers to the occurrence of repeated bouts of abdominal discomfort. This definition is vague as it does not specify the duration of the periods of remission, nor the patient's overall condition during these periods. The distinction between recurrent colic and chronic colic, in which pain may wax and wane with variable intensity for more than 48 hours without signs of strangulation, can be difficult and is merely based on the subjective assessment of the attending clinician. However, for the sake of this article, recurrent colic will be defined as two or more episodes of abdominal pain, separated by a period of remission of at least several days.
Simple mastitis bacteriology for the practice
Authors: Buswell John
Published: October 2010

VETERINARY practitioners can be greatly assisted in their knowledge of mastitis by the laboratory examination of aseptically taken milk samples. The pathogens, the scale of the problem and the success of the prescribed therapy can be assessed using simple laboratory techniques. It is essential, however, that certain principles are adopted and followed consistently. This article covers the basic techniques for sampling and culturing and the simple identification of the principal mastitis milk pathogens, while advising on the methods and interpretation of the results.
Supportive therapy of generalised endotoxaemia in cattle using hypertonic saline
Authors: Sargison Neil , Scott Phil
Published: October 2010

ENDOTOXAEMIA in adult cattle commonly results from peracute Gram‐negative bacterial infections including [i]Escherichia coli[/i] mastitis, severe endometritis, septic peritonitis and acute abdominal catastrophes where disruption of the intestinal mucosal barrier may allow absorption of endotoxin. This practice tip describes the technique of hypertonic saline infusion, which has proved to be a useful adjunct in the treatment of generalised endotoxaemia.
Surgical asepsis: principles and protocols
Authors: Baines Stephen
Published: October 2010

WOUND infections have been a major problem since surgery began and, despite improved techniques to avoid and combat them, they remain an important complication of surgery. This article discusses the stages in the prevention of wound contamination. The basic principle of aseptic technique is that microbiological contamination and subsequent infection cannot occur if microorganisms are totally excluded from a wound. The reality of aseptic technique is a working set of complementary and independent technologies and operating room protocols designed to prevent or minimise microbiological contamination of the surgical wound. All items that come into contact with the wound should be sterile. If an item cannot be made sterile, it is rendered surgically clean by washing with antiseptics or disinfectants which destroy most, but not all, microorganisms.
Credit control in equine practice
Authors: Green Peter
Published: October 2010

PARTNERS in mixed practices will tell you that equine clients are the most demanding, hardest to satisfy and are less loyal to the practice than farmers or small animal clients. To make matters worse, so the story goes, they do not pay their bills. If these opinions have a basis in fact, practices which generate the majority or all of their income from equine work must surely suffer more from the problems associated with slow payment and high client debt to the practice. Credit control in equine practice is affected by the nature of the relationships between veterinary surgeon, client and patient since some of the features of these relationships are not encountered in either small animal or farm practice.
It shouldn't happen to a vet…
Authors: Tindall John
Published: October 2010

THE case described in this article illustrates the confusion surrounding the legal requirements demanded when a veterinary surgeon is called out to an emergency and is required to act as an ‘agent of necessity’.
A Clinician's approach to the investigation of otitis externa
Authors: Little Chris
Published: October 2010

INFLAMMATION of the ear canal is one of the most common clinical problems encountered in small animal practice. There are many causes ‐ the ear canal is lined by skin so that virtually any dermatopathy can initiate otitis externa. Once the ear canal becomes inflamed and obstructed by debris, and self‐trauma starts to play a part in perpetuating the problem, diagnosis of the cause frequently becomes difficult and frustrating. This article, the first of three on otitis externa, highlights some causes and aims to lay out an easy approach to its investigation. The second article, which will be published in the next issue, will consider medical therapy and the third article, surgery.
Partners' cars ‐ profile versus practicality
Authors: Gunn Dixon
Published: October 2010

THE value of the cars owned by a practice normally forms only a small part of the total value of the assets of the whole practice. However, the problems caused by cars are often out of all proportion to their value. Rationality is never used in a debate on an emotive subject, and partners' cars are, most certainly, an emotive issue.
Wound management in small animal practice
Authors: Anderson Davina
Published: October 2010

TRAUMATIC wounds are a common presentation in small animal practice. Prolonged healing times of these injuries are expensive and distressing for the client and patient. The normal healing process is efficient and an understanding of the cellular physiology of the healing wound enables the surgeon to make objective decisions to manipulate the process to the patient's advantage; for example, performing a surgical reconstruction or skin graft may be less expensive in terms of dressings and time than allowing a wound to heal by second intention. Broadly, the aims of wound management are: a functional and cosmetic repair; relief of pain and distress to the animal; economic and time efficient procedures; and prompt decision making in the event of signs of delayed healing. This article covers some of the aspects of managing wounds in the early stages.
Approaching the bank
Authors: Matthews Keith
Published: October 2010

AFTER qualifying and spending time gaining valuable experience, many assistants eventually decide to reap the rewards of joining a partnership, acquiring an established practice or starting a new business. Whichever the case, the initial excitement will be tinged with apprehension about raising the necessary capital because, although rich in knowledge, the majority may well be poor in asset terms. There are specialist lenders who understand and are equipped to deal with the needs of the veterinary profession, but the traditional lending source is a bank where an account will probably have been maintained since student days. This article discusses what information should be presented to the bank when asking for financial backing.
Greening veterinary practice
Authors: Foster John
Published: October 2010

THE time has come for environmental consciousness in veterinary practice, says John Foster. Here, he gives some hints on how to achieve targets which will have environmental benefits and cost saving implications.