bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of Lateral Flagella of Selenomonas ruminantium
Authors: Haya Shohei , Tokumaru Yuya , Abe Naoki , Kaneko Jun , Aizawa Shin-ichi 
Published: February 2011

ABSTRACT

Selenomonas ruminantium
produces a tuft of flagella near the midpoint of the cell body and swims by rotating the cell body along the cell's long axis. The flagellum is composed of a single kind of flagellin, which is heavily glycosylated. The hook length of
S. ruminantium
is almost double that of
Salmonella
.
Deletion or Overexpression of Mitochondrial NAD
+
Carriers in
Saccharomyces cerevisiae
Alters Cellular NAD and ATP Contents and Affects Mitochondrial Metabolism and the Rate of Glycolysis
Authors: Agrimi Gennaro , Brambilla Luca , Frascotti Gianni , Pisano Isabella , Porro Danilo , Vai Marina , Palmieri Luigi 
Published: February 2011

ABSTRACT

The modification of enzyme cofactor concentrations can be used as a method for both studying and engineering metabolism. We varied
Saccharomyces cerevisiae
mitochondrial NAD levels by altering expression of its specific mitochondrial carriers. Changes in mitochondrial NAD levels affected the overall cellular concentration of this coenzyme and the cellular metabolism. In batch culture, a strain with a severe NAD depletion in mitochondria succeeded in growing, albeit at a low rate, on fully respiratory media. Although the strain increased the efficiency of its oxidative phosphorylation, the ATP concentration was low. Under the same growth conditions, a strain with a mitochondrial NAD concentration higher than that of the wild type similarly displayed a low cellular ATP level, but its growth rate was not affected. In chemostat cultures, when cellular metabolism was fully respiratory, both mutants showed low biomass yields, indicative of impaired energetic efficiency. The two mutants increased their glycolytic fluxes, and as a consequence, the Crabtree effect was triggered at lower dilution rates. Strikingly, the mutants switched from a fully respiratory metabolism to a respirofermentative one at the same specific glucose flux as that of the wild type. This result seems to indicate that the specific glucose uptake rate and/or glycolytic flux should be considered one of the most important independent variables for establishing the long-term Crabtree effect. In cells growing under oxidative conditions, bioenergetic efficiency was affected by both low and high mitochondrial NAD availability, which suggests the existence of a critical mitochondrial NAD concentration in order to achieve optimal mitochondrial functionality.
Cholate-Stimulated Biofilm Formation by Lactococcus lactis Cells
Authors: Zaidi Arsalan Haseeb , Bakkes Patrick J. , Krom Bastiaan P. , van der Mei Henny C. , Driessen Arnold J. M. 
Published: February 2011

ABSTRACT

Bile acid resistance by
Lactococcus lactis
depends on the ABC-type multidrug transporter LmrCD. Upon deletion of the
lmrCD
genes, cells can reacquire bile acid resistance upon prolonged exposure to cholate, yielding the Δ
lmrCD
r
strain. The resistance mechanism in this strain is non-transporter based. Instead, cells show a high tendency to flocculate, suggesting cell surface alterations. Contact angle measurements demonstrate that the Δ
lmrCD
r
cells are equipped with an increased cell surface hydrophilicity compared to those of the parental and wild-type strains, while the surface hydrophilicity is reduced in the presence of cholate. Δ
lmrCD
r
cells are poor in biofilm formation on a hydrophobic polystyrene surface, but in the presence of subinhibitory concentrations of cholate, biofilm formation is strongly stimulated. Biofilm cells show an enhanced extracellular polymeric substance production and are highly resistant to bile acids. These data suggest that non-transporter-based cholate resistance in
L. lactis
is due to alterations in the cell surface that stimulate cells to form resistant biofilms.
Continuous Control of the Flow in Biochemical Pathways through 5′ Untranslated Region Sequence Modifications in mRNA Expressed from the Broad-Host-Range Promoter
Pm
Authors: Lale Rahmi , Berg Laila , Stüttgen Friederike , Netzer Roman , Stafsnes Marit , Brautaset Trygve , Vee Aune Trond Erik , Valla Svein 
Published: February 2011

ABSTRACT

The inducible
Pm
promoter integrated into broad-host-range plasmid RK2 replicons can be fine-tuned continuously between the uninduced and maximally induced levels by varying the inducer concentrations. To lower the uninduced background level while still maintaining the inducibility for applications in, for example, metabolic engineering and synthetic (systems) biology, we report here the use of mutations in the
Pm
DNA region corresponding to the 5′ untranslated region of mRNA (UTR). Five UTR variants obtained by doped oligonucleotide mutagenesis and selection, apparently reducing the efficiency of translation, were all found to display strongly reduced uninduced expression of three different reporter genes (encoding β-lactamase, luciferase, and phosphoglucomutase) in
Escherichia coli
. The ratio between induced and uninduced expression remained the same or higher compared to cells containing a corresponding plasmid with the wild-type UTR. Interestingly, the UTR variants also displayed similar effects on expression when substituted for the native UTR in another and constitutive promoter,
P1
(

P
antitet

), indicating a broad application potential of these UTR variants. Two of the selected variants were used to control the production of the C
50
carotenoid sarcinaxanthin in an engineered strain of
E. coli
that produces the precursor lycopene. Sarcinaxanthin is produced in this particular strain by expressing three
Micrococcus luteus
derived genes from the promoter
Pm
. The results indicated that UTR variants can be used to eliminate sarcinaxanthin production under uninduced conditions, whereas cells containing the corresponding plasmid with a wild-type UTR produced ca. 25% of the level observed under induced conditions.
Reduction of Escherichia coli O157:H7 Shedding in Cattle by Addition of Chitosan Microparticles to Feed
Authors: Jeong Kwang Cheol , Kang Min Young , Kang Jihun , Baumler David J. , Kaspar Charles W. 
Published: February 2011

ABSTRACT

Enterohemorrhagic
Escherichia coli
O157:H7 (EHEC) is a significant human pathogen that resides in healthy cattle. It is thought that a reduction in the prevalence and numbers of EHEC in cattle will reduce the load of EHEC entering the food chain. To this end, an intervention strategy involving the addition of chitosan microparticles (CM) to feed in order to reduce the carriage of this pathogen in cattle was evaluated. Experiments with individual Holstein calves and a crossover study found that the addition of CM to feed decreased
E. coli
O157:H7 shedding. In the crossover study, CM resulted in statistically significant reductions in the numbers recovered from rectal swab samples (
P
< 0.05) and the duration of shedding (
P
< 0.05). The effects of feeding CM to calves differed, indicating that the optimal levels of CM may differ between animals or that other factors are involved in the interaction between CM and
E. coli
O157:H7.
In vitro
studies demonstrated that
E. coli
O157:H7 binds to CM, suggesting that the reduction in shedding may result at least in part from the binding of positively charged CM to negatively charged
E. coli
cells. Additional studies are needed to determine the impact of CM feeding on animal production, but the results from this study indicate that supplementing feed with CM reduces the shedding of
E. coli
O157:H7 in cattle.
Improvement of the Efficacy of Linear Undecapeptides against Plant-Pathogenic Bacteria by Incorporation of
d
-Amino Acids
Authors: Güell Imma , Cabrefiga Jordi , Badosa Esther , Ferre Rafael , Talleda Montserrat , Bardají Eduard , Planas Marta , Feliu Lidia , Montesinos Emilio 
Published: February 2011

ABSTRACT

A set of 31 undecapeptides, incorporating 1 to 11
d
-amino acids and derived from the antimicrobial peptide BP100 (KKLFKKILKYL-NH
2
), was designed and synthesized. This set was evaluated for inhibition of growth of the plant-pathogenic bacteria
Erwinia amylovora
,
Pseudomonas syringae
pv. syringae, and
Xanthomonas axonopodis
pv. vesicatoria, hemolysis, and protease degradation. Two derivatives were as active as BP100, and 10 peptides displayed improved activity, with the all-
d
isomer being the most active. Twenty-six peptides were less hemolytic than BP100, and all peptides were more stable against protease degradation. Plant extracts inhibited the activity of BP100 as well as that of the
d
-isomers. Ten derivatives incorporating one
d
-amino acid each were tested in an infectivity inhibition assay with the three plant-pathogenic bacteria by using detached pear and pepper leaves and pear fruits. All 10 peptides studied were active against
E. amylovora
, 6 displayed activity against
P. syringae
pv. syringae, and 2 displayed activity against
X. axonopodis
pv. vesicatoria. Peptides BP143 (KKL
F
KKILKYL-NH
2
) and BP145 (K
K
LFKKILKYL-NH
2
), containing one
d
-amino acid at positions 4 and 2 (underlined), respectively, were evaluated in whole-plant assays for the control of bacterial blight of pepper and pear and fire blight of pear. Peptide BP143 was as effective as streptomycin in the three pathosystems, was more effective than BP100 against bacterial blight of pepper and pear, and equally effective against fire blight of pear.
Lack of Correlation between Turnover of Low-Molecular-Weight Dissolved Organic Carbon and Differences in Microbial Community Composition or Growth across a Soil pH Gradient
Authors: Rousk Johannes , Brookes Philip C. , Glanville Helen C. , Jones David L. 
Published: February 2011

ABSTRACT
We studied how soil pH (pHs 4 to 8) influenced the mineralization of low-molecular-weight (LMW)-dissolved organic carbon (DOC) compounds, and how this compared with differences in microbial community structure. The mineralization of LMW-DOC compounds was not systematically connected to differences in soil pH, consistent with soil respiration. In contrast, the microbial community compositions differed dramatically. This suggests that microbial community composition data will be of limited use in improving the predictive power of soil C models.
Protein Kinase B Gene Homologue
pkbR1
Performs One of Its Roles at First Finger Stage of Dictyostelium
Authors: Ochiai Hiroshi , Takeda Kosuke , Fukuzawa Masashi , Kato Atsushi , Takiya Shigeharu , Ohmachi Tetsuo 
Published: February 2011

ABSTRACT

Dictyostelium discoideum
has protein kinases AKT/PKBA and PKBR1 that belong to the AGC family of kinases. The protein kinase B-related kinase (PKBR1) has been studied with emphasis on its role in chemotaxis, but its roles in late development remained obscure. The
pkbR1
null mutant stays in the first finger stage for about 16 h or longer. Only a few aggregates continue to the migrating slug stage; however, the slugs immediately go back probably to the previous first finger stage and stay there for approximately 37 h. Finally, the mutant fingers diversify into various multicellular bodies. The expression of the
pkbR1
finger protein probably is required for development to the slug stage and to express
ecmB
, which is first observed in migrating slugs. The mutant also showed no
ST-lacZ
expression, which is of the earliest step in differentiation to one of the stalk cell subtypes. The
pkbR1
null mutant forms a small number of aberrant fruiting bodies, but in the presence of 10% of wild-type amoebae the mutant preferentially forms viable spores, driving the wild type to form nonviable stalk cells. These results suggest that the mutant has defects in a system that changes the physiological dynamics in the prestalk cell region of a finger. We suggest that the arrest of its development is due to the loss of the second wave of expression of a protein kinase A catalytic subunit gene (
pkaC
) only in the prestalk region of the
pkbR1
null mutant.
Role of Four Calcium Transport Proteins, Encoded bynca-1,nca-2,nca-3, andcax, in Maintaining Intracellular Calcium Levels in Neurospora crassa
Authors: Bowman Barry J. , Abreu Stephen , Margolles-Clark Emilio , Draskovic Marija , Bowman Emma Jean 
Published: February 2011

ABSTRACTWe have examined the distribution of calcium inNeurospora crassaand investigated the role of four predicted calcium transport proteins. The results of cell fractionation experiments showed 4% of cellular calcium in mitochondria, approximately 11% in a dense vacuolar fraction, 40% in an insoluble form that copurifies with microsomes, and 40% in a high-speed supernatant, presumably from large vacuoles that had broken. Strains lacking NCA-1, a SERCA-type Ca2+-ATPase, or NCA-3, a PMC-type Ca2+-ATPase, had no obvious defects in growth or distribution of calcium. A strain lacking NCA-2, which is also a PMC-type Ca2+-ATPase, grew slowly in normal medium and was unable to grow in high concentrations of calcium tolerated by the wild type. Furthermore, when grown in normal concentrations of calcium (0.68 mM), this strain accumulated 4- to 10-fold more calcium than other strains, elevated in all cell fractions. The data suggest that NCA-2 functions in the plasma membrane to pump calcium out of the cell. In this way, it resembles the PMC-type enzymes of animal cells, not the Pmc1p enzyme inSaccharomyces cerevisiaethat resides in the vacuole. Strains lacking thecaxgene, which encodes a Ca2+/H+exchange protein in vacuolar membranes, accumulate very little calcium in the dense vacuolar fraction but have normal levels of calcium in other fractions. Thecaxknockout strain has no other observable phenotypes. These data suggest that “the vacuole” is heterogeneous and that the dense vacuolar fraction contains an organelle that is dependent upon the CAX transporter for accumulation of calcium, while other components of the vacuolar system have multiple calcium transporters.
Quantifying the Importance of Galactofuranose in Aspergillus nidulans Hyphal Wall Surface Organization by Atomic Force Microscopy
Authors: Paul Biplab C. , El-Ganiny Amira M. , Abbas Mariam , Kaminskyj Susan G. W. , Dahms Tanya E. S. 
Published: February 2011

ABSTRACT

The fungal wall mediates cell-environment interactions. Galactofuranose (Gal
f
), the five-member ring form of galactose, has a relatively low abundance in
Aspergillus
walls yet is important for fungal growth and fitness.
Aspergillus nidulans
strains deleted for Gal
f
biosynthesis enzymes UgeA (UDP-glucose-4-epimerase) and UgmA (UDP-galactopyranose mutase) lacked immunolocalizable Gal
f
, had growth and sporulation defects, and had abnormal wall architecture. We used atomic force microscopy and force spectroscopy to image and quantify cell wall viscoelasticity and surface adhesion of
ugeA
Δ and
ugmA
Δ strains. We compared the results for
ugeA
Δ and
ugmA
Δ strains with the results for a wild-type strain (AAE1) and the
ugeB
deletion strain, which has wild-type growth and sporulation. Our results suggest that UgeA and UgmA are important for cell wall surface subunit organization and wall viscoelasticity. The
ugeA
Δ and
ugmA
Δ strains had significantly larger surface subunits and lower cell wall viscoelastic moduli than those of AAE1 or
ugeB
Δ hyphae. Double deletion strains (
ugeA
Δ
ugeB
Δ and
ugeA
Δ
ugmA
Δ) had more-disorganized surface subunits than single deletion strains. Changes in wall surface structure correlated with changes in its viscoelastic modulus for both fixed and living hyphae. Wild-type walls had the largest viscoelastic modulus, while the walls of the double deletion strains had the smallest. The
ugmA
Δ strain and particularly the
ugeA
Δ
ugmA
Δ double deletion strain were more adhesive to hydrophilic surfaces than the wild type, consistent with changes in wall viscoelasticity and surface organization. We propose that Gal
f
is necessary for full maturation of
A. nidulans
walls during hyphal extension.
Crystal Structure of the Autochaperone Region from the Shigella flexneri Autotransporter IcsA
Authors: Kühnel Karin , Diezmann Dagmar 
Published: February 2011

ABSTRACT

The IcsA (
i
ntra
c
ellular
s
pread gene
A
) autotransporter from
Shigella flexneri
is a key virulence factor. We identified a stable fragment comprising residues 591 to 758, which corresponds to the autochaperone region of the IcsA passenger domain. We showed that thermal unfolding of the autochaperone region is reversible and determined its crystal structure at 2.0-Å resolution.
Elucidation of the Regulon and
cis
-Acting Regulatory Element of HrpB, the AraC-Type Regulator of a Plant Pathogen-Like Type III Secretion System in Burkholderia pseudomallei
Authors: Lipscomb Lyla , Schell Mark A. 
Published: February 2011

ABSTRACT

The human pathogen
Burkholderia pseudomallei
possesses multiple type III secretion system (T3SS) gene clusters. One of these, the
B. pseudomallei
T3SS2 (T3SS2
bp
) gene cluster, which apparently plays no role in animal virulence, is also found in six additional
Burkholderia
spp. and is very similar to T3SSs found in phytopathogenic
Xanthomonas
spp. and
Ralstonia solanacearum
. The T3SS2
bp
gene cluster also encodes an AraC-type regulatory protein (HrpB
bp
) that is an ortholog of HrpB, the master regulator of the
R. solanacearum
T3SS (T3SS
rso
) and its secreted effectors. Transcriptome analysis showed that HrpB
bp
activates the expression of T3SS2
bp
genes, as well as their orthologs in
R. solanacearum
. In addition to activating T3SS2
bp
, HrpB
bp
also upregulates the expression of ∼30 additional
B. pseudomallei
genes, including some that may confer production of adhesive pili, a polyketide toxin, several putative T3SS2
bp
-secreted effectors, and components of a regulatory cascade. T3SS2
bp
promoter regions were found to contain a conserved DNA motif (p2
bp
box) identical in sequence and position to the hrp
II
box required for HrpB-dependent T3SS
rso
transcription activation. The p2
bp
box is also present in the promoter regions of the essentially identical T3SS found in the very closely related species
Burkholderia thailandensis
(T3SS2
bt
). Analysis of p2
bp
box mutants showed that it is essential for HrpB
bp
-mediated transcription activation in both species. Although it has been suggested that T3SS2
bp
and T3SS2
bt
may function in phytopathogenicity, we were unable to demonstrate a phytopathogenic phenotype for
B. thailandensis
in three different plant hosts.
The Regulatory C-Terminal Domain of Subunit ε of F
o
F
1
ATP Synthase Is Dispensable for Growth and Survival of Escherichia coli
Authors: Taniguchi Naohiro , Suzuki Toshiharu , Berney Michael , Yoshida Masasuke , Cook Gregory M. 
Published: February 2011

ABSTRACT

The C-terminal domain of subunit ε of the bacterial F
o
F
1
ATP synthase is reported to be an intrinsic inhibitor of ATP synthesis/hydrolysis activity
in vitro
, preventing wasteful hydrolysis of ATP under low-energy conditions. Mutants defective in this regulatory domain exhibited no significant difference in growth rate, molar growth yield, membrane potential, or intracellular ATP concentration under a wide range of growth conditions and stressors compared to wild-type cells, suggesting this inhibitory domain is dispensable for growth and survival of
Escherichia coli
.
A UDP-HexNAc:Polyprenol-P GalNAc-1-P Transferase (WecP) Representing a New Subgroup of the Enzyme Family
Authors: Merino Susana , Jimenez Natalia , Molero Raquel , Bouamama Lamiaa , Regué Miguel , Tomás Juan M. 
Published: February 2011

ABSTRACT

The
Aeromonas hydrophila
AH-3 WecP represents a new class of UDP-HexNAc:polyprenol-P HexNAc-1-P transferases. These enzymes use a membrane-associated polyprenol phosphate acceptor (undecaprenyl phosphate [Und-P]) and a cytoplasmic UDP-
d
-
N
-acetylhexosamine sugar nucleotide as the donor substrate. Until now, all the WecA enzymes tested were able to transfer UDP-GlcNAc to the Und-P. In this study, we present
in vitro
and
in vivo
proofs that
A. hydrophila
AH-3 WecP transfers GalNAc to Und-P and is unable to transfer GlcNAc to the same enzyme substrate. The molecular topology of WecP is more similar to that of WbaP (UDP-Gal polyprenol-P transferase) than to that of WecA (UDP-GlcNAc polyprenol-P transferase). WecP is the first UDP-HexNAc:polyprenol-P GalNAc-1-P transferase described.
On the relevance of personal responsibility in priority setting: a cross-sectional survey among Norwegian medical doctors
Authors: Bringedal Berit , Feiring Eli 
Published: February 2011

The debate on responsibility for health takes place within political philosophy and in policy setting. It is increasingly relevant in the context of rationing scarce resources as a substantial, and growing, proportion of diseases in high-income countries is attributable to lifestyle. Until now, empirical studies of medical professionals' attitudes towards personal responsibility for health as a component of prioritisation have been lacking. This paper explores to what extent Norwegian physicians find personal responsibility for health relevant in prioritisation and what type of risk behaviour they consider relevant in such decisions. The proportion who agree that it should count varies from 17.1% (‘Healthcare priority should depend on the patient's responsibility for the disease’) to 26.9% (‘Access to scarce organ transplants should depend on the patient's responsibility for the disease’). Higher age and being male is positively correlated with acceptance. The doctors are more willing to consider substance use in priority setting decisions than choices on food and exercise. The findings reveal that a sizeable proportion have beliefs that conflict with the norms stated in the Norwegian Patient Act. It may be possible that the implementation of legal regulations can be hindered by the opposing attitudes among doctors. A further debate on the role personal responsibility should play in priority setting seems warranted. However, given the deep controversies about the concept of health responsibility and its application, it would be wise to proceed with caution.DesignNationally representative cross-sectional study.SettingPanel-data.Participants1072 respondents, response rate 65%.
Economic costs attributable to smoking in China: update and an 8-year comparison, 2000–2008
Authors: Yang Lian , Sung Hai-Yen , Mao Zhengzhong , Hu Teh-wei , Rao Keqin 
Published: February 2011

ObjectiveTo estimate the health-related economic costs attributable to smoking in China for persons aged 35 and older in 2003 and in 2008 and to compare these costs with the respective results from 2000.MethodsA prevalence-based, disease-specific approach was used to estimate smoking-attributable direct and indirect economic costs. The primary data source was the 2003 and 2008 China National Health Services Survey, which contains individual participant's smoking status, healthcare use and expenditures.ResultsThe total economic cost of smoking in China amounted to $17.1 billion in 2003 and $28.9 billion in 2008 (both measured in 2008 constant US$). Direct smoking-attributable healthcare costs in 2003 and 2008 were $4.2 billion and $6.2 billion, respectively. Indirect economic costs in 2003 and 2008 were $12.9 billion and $22.7 billion, respectively. Compared to 2000, the direct costs of smoking rose by 72% in 2003 and 154% in 2008, while the indirect costs of smoking rose by 170% in 2003 and 376% in 2008.ConclusionsThe economic burden of cigarette smoking has increased substantially in China during the past decade and is expected to continue to increase as the national economy and the price of healthcare services grow. Stronger intervention measures against smoking should be taken without delay to reduce the health and financial losses caused by smoking.