bluuebunny/crossref_metadata_2025_split huggingface dataset:
Osmotically Regulated Synthesis of the Compatible Solute Ectoine in
Bacillus pasteurii
and Related
Bacillus
spp
Authors: Kuhlmann Anne U. , Bremer Erhard 
Published: February 2003

ABSTRACT

By using natural-abundance
13
C-nuclear magnetic resonance spectroscopy and high-performance liquid chromatography (HPLC) analysis we have investigated the types of compatible solutes that are synthesized de novo in a variety of
Bacillus
species under high-osmolality growth conditions. Five different patterns of compatible solute production were found among the 13
Bacillus
species we studied.
Bacillus subtilis
,
B. licheniformis
, and
B. megaterium
produced proline;
B. cereus
,
B. circulans
,
B. thuringiensis
,
Paenibacillus polymyxa
, and
Aneurinibacillus aneurinilyticus
synthesized glutamate;
B. alcalophilus
,
B. psychrophilus
, and
B. pasteurii
synthesized ectoine; and
Salibacillus
(formerly
Bacillus
)
salexigens
produced both ectoine and hydroxyectoine, whereas
Virgibacillus
(formerly
Bacillus
)
pantothenticus
synthesized both ectoine and proline. Hence, the ability to produce the tetrahydropyrimidine ectoine under hyperosmotic growth conditions is widespread within the genus
Bacillus
and closely related taxa. To study ectoine biosynthesis within the group of
Bacillus
species in greater detail, we focused on
B. pasteurii
. We cloned and sequenced its ectoine biosynthetic genes (
ectABC
). The
ectABC
genes encode the diaminobutyric acid acetyltransferase (EctA), the diaminobutyric acid aminotransferase (EctB), and the ectoine synthase (EctC). Together these proteins constitute the ectoine biosynthetic pathway, and their heterologous expression in
B. subtilis
led to the production of ectoine. Northern blot analysis demonstrated that the
ectABC
genes are genetically organized as an operon whose expression is strongly enhanced when the osmolality of the growth medium is raised. Primer extension analysis allowed us to pinpoint the osmoregulated promoter of the
B. pasteurii ectABC
gene cluster. HPLC analysis of osmotically challenged
B. pasteurii
cells revealed that ectoine production within this bacterium is finely tuned and closely correlated with the osmolality of the growth medium. These observations together with the osmotic control of
ectABC
transcription suggest that the de novo synthesis of ectoine is an important facet in the cellular adaptation of
B. pasteurii
to high-osmolarity surroundings.
Enhanced Exopolysaccharide Production by Metabolic Engineering of
Streptococcus thermophilus
Authors: Levander Fredrik , Svensson Malin , Rådström Peter 
Published: February 2003

ABSTRACT

It is possible that the low levels of production of exopolysaccharides (EPSs) by lactic acid bacteria could be improved by altering the levels of enzymes in the central metabolism that influence the production of precursor nucleotide sugars. To test this hypothesis, we identified and cloned the
galU
gene, which codes for UDP glucose pyrophosphorylase (GalU) in
Streptococcus thermophilus
LY03. Homologous overexpression of the gene led to a 10-fold increase in GalU activity but did not have any effect on the EPS yield when lactose was the carbon source. However, when
galU
was overexpressed in combination with
pgmA
, which encodes phosphoglucomutase (PGM), the EPS yield increased from 0.17 to 0.31 g/mol of carbon from lactose. A galactose-fermenting LY03 mutant (Gal
+
) with increased activities of the Leloir enzymes was also found to have a higher EPS yield (0.24 g/mol of carbon) than the parent strain. The EPS yield was further improved to 0.27 g/mol of carbon by overexpressing
galU
in this strain. However, the highest EPS yield, 0.36 g/mol of carbon, was obtained when
pgmA
was knocked out in the Gal
+
strain. Measurements of the levels of intracellular metabolites in the cultures revealed that the Gal
+
strains had considerably higher glucose 1-phosphate levels than the other strains, and the strain lacking PGM activity had threefold-higher levels of glucose 1-phosphate than the other Gal
+
strains. These results show that it is possible to increase EPS production by altering the levels of enzymes in the central carbohydrate metabolism.
Expression of the Xylulose 5-Phosphate Phosphoketolase Gene,
xpkA
, from
Lactobacillus pentosus
MD363 Is Induced by Sugars That Are Fermented via the Phosphoketolase Pathway and Is Repressed by Glucose Mediated by CcpA and the Mannose Phosphoenolpyruvate Phosphotransferase System
Authors: Posthuma Clara C. , Bader Rechien , Engelmann Roswitha , Postma Pieter W. , Hengstenberg Wolfgang , Pouwels Peter H. 
Published: February 2003

ABSTRACT

Purification of xylulose 5-phosphate phosphoketolase (XpkA), the central enzyme of the phosphoketolase pathway (PKP) in lactic acid bacteria, and cloning and sequence analysis of the encoding gene,
xpkA
, from
Lactobacillus pentosus
MD363 are described.
xpkA
encodes a 788-amino-acid protein with a calculated mass of 88,705 Da. Expression of
xpkA
in
Escherichia coli
led to an increase in XpkA activity, while an
xpkA
knockout mutant of
L. pentosus
lost XpkA activity and was not able to grow on energy sources that are fermented via the PKP, indicating that
xpkA
encodes an enzyme with phosphoketolase activity. A database search revealed that there are high levels of similarity between XpkA and a phosphoketolase from
Bifidobacterium lactis
and between XpkA and a (putative) protein present in a number of evolutionarily distantly related organisms (up to 54% identical residues). Expression of
xpkA
in
L. pentosus
was induced by sugars that are fermented via the PKP and was repressed by glucose mediated by carbon catabolite protein A (CcpA) and by the mannose phosphoenolpyruvate phosphotransferase system. Most of the residues involved in correct binding of the cofactor thiamine pyrophosphate (TPP) that are conserved in transketolase, pyruvate decarboxylase, and pyruvate oxidase were also conserved at a similar position in XpkA, implying that there is a similar TPP-binding fold in XpkA.
Detection and Quantification of
Pfiesteria piscicida
by Using the Mitochondrial Cytochrome
b
Gene
Authors: Zhang Huan , Lin Senjie 
Published: February 2003

ABSTRACT

Mitochondrial cytochrome
b
was isolated from the dinoflagellate
Pfiesteria piscicida
, and the utility of the gene for species identification was examined. One of the primer sets designed was shown to be highly specific for
P. piscicida
. A time step PCR protocol was used to demonstrate the potential of this primer set for quantification of this species.
Simple Procedure for Rapid Identification of
Vibrio cholerae
from the Aquatic Environment
Authors: Choopun Nipa , Louis Valérie , Huq Anwar , Colwell Rita R. 
Published: February 2003

ABSTRACT

Biochemical tests commonly used to screen for
Vibrio cholerae
in environmental samples were evaluated, and we found that a combination of alkaline peptone enrichment followed by streaking on thiosulfate citrate bile salts sucrose agar and testing for arginine dihydrolase activity and esculin hydrolysis was an effective rapid technique to screen for aquatic environmental
V. cholerae
. This technique provided 100% sensitivity and ≥70% specificity.
Quantitative relations between exposure to respirable quartz and risk of silicosis
Authors: Buchanan D , Miller B G , Soutar C A 
Published: February 2003

Aims:To reanalyse exposure-response data from a Scottish colliery to gain a more detailed knowledge of the relations between exposure to quartz and risks of silicosis in coal miners, and hence inform the debate on an appropriate occupational standard for respirable quartz.Methods:Detailed data on working times at different quartz concentrations were combined to produce exposure profiles for miners who had provided a full chest radiograph at a follow up survey. Logistic regression methods were used to model profusion of radiographic abnormalities category 2/1+, and a general exposure index was used to compare different quartz exposure measures in these models.Results:Results in 371 men aged 50–74 indicated that cumulative quartz exposure at higher concentrations resulted in proportionally greater risks of abnormalities. One g.h.m−3of cumulative exposure at quartz concentrations greater than 2 mg.m−3was estimated to have equivalent risks to 3 g.h.m−3at lower concentrations. The timing of exposure relative to follow up appeared less important, although the study had limited power to compare different lag periods between exposure and effect.Conclusions:Quantification of the risks of silicosis should take account of variations in quartz exposure intensity, particularly for exposure to concentrations of greater than 1 or 2 mg.m−3, even if exposure is for relatively short periods. The risks of silicosis over a working lifetime can rise dramatically with even brief exposure to such high quartz concentrations. Risk estimates are given, to inform choice of control limits.
Effect of trihalomethane exposure on fetal development
Authors: Wright J M , Schwartz J , Dockery D W 
Published: February 2003

Aims:To examine the effect of trimester specific and pregnancy average total trihalomethane (TTHM) exposure on infant birth weight, low birth weight, and intrauterine growth retardation in term births, as well as gestational age and preterm delivery in all births.Methods:Cross sectional analysis of 56 513 singleton infants born to residents of Massachusetts during 1990. City specific aggregate data were used to estimate maternal exposure to TTHM concentration; individual maternal information was used to adjust for confounding.Results:Increased pregnancy average and second trimester TTHM exposure were associated with small for gestational age and reductions in birth weight after adjusting for potential confounding variables. Compared to ≤60 μg/l, pregnancy average TTHM exposure over 80 μg/l was associated with a 32 g reduction in birth weight. There was a 23 g reduction in birth weight in infants born to mothers exposed to greater than 80 μg/l TTHM during the second trimester. For each 20 μg/l increase in TTHM, the estimated reduction in birth was 2.8 g for pregnancy average exposure and 2.6 g for second trimester exposure. An increased risk of small for gestational age births was found for pregnancy average (odds ratio (OR) 1.14; 95% CI 1.02 to 1.26) and second trimester (OR 1.13, 95% CI 1.03 to 1.24) TTHM levels greater than 80 μg/l. There was no evidence of an association between preterm delivery and increased TTHM levels, but there were slight increases in gestational duration associated with TTHM concentrations.Conclusions:Maternal exposure to THMs may be associated with fetal growth retardation. Our findings are consistent with most previous work, although we generally found smaller effects of TTHMs on low birth weight and intrauterine growth retardation.
Mental health of British farmers
Authors: Thomas H V , Lewis G , Thomas D Rh , Salmon R L , Chalmers R M , Coleman T J , Kench S M , Morgan-Capner P , Meadows D , Sillis M , Softley P 
Published: February 2003

Aims:To estimate the prevalence of neurotic symptoms in a sample of British farmers, to investigate whether farming characteristics are associated with psychiatric morbidity, and to test the hypothesis that British farmers have a higher prevalence of depression and thoughts of life not worth living than the British household population.Methods:A total of 425 farmers from Hereford, Norwich, and Preston completed the Revised Clinical Interview Schedule (CIS-R) by computer between March and July 1999. The comparison cohort consisted of 9830 private householders aged 16–64 from the Office of Population Censuses and Surveys National Psychiatric Morbidity Surveys of Great Britain carried out in 1993 in which the CIS-R was administered. All analyses used the commands developed specifically for survey data available in Stata version 6.0.Results:Taking a threshold of an overall score of 12 or more on the CIS-R, only 6% of farmers reported clinically relevant psychiatric morbidity. Psychiatric morbidity was not significantly associated with farm type or size in this study. Farmers reported a lower prevalence of psychiatric morbidity than the general population but were more likely to report thinking that life is not worth living, particularly after the low prevalence of psychiatric morbidity had been taken into account (odds ratio 2.56, 95% CI 1.39 to 4.69). When restricting the comparison to only rural or semirural householders, this increased risk was even more pronounced (odds ratio 3.26, 95% CI 1.51 to 7.02).Conclusions:The relation between depression and suicidal ideation seems to be quite different among farmers and the general population and warrants further investigation. We have shown it is possible to measure mental health systematically in a sample of British farmers. This study should be repeated in the aftermath of the foot and mouth crisis.
Lymphohaematopoietic system cancer incidence in an urban area near a coke oven plant: an ecological investigation
Authors: Parodi S , Vercelli M , Stella A , Stagnaro E , Valerio F 
Published: February 2003

Aims:To evaluate the incidence risk of lymphohaematopoietic cancers for the 1986–94 period in Cornigliano, a district of Genoa (Italy), where a coke oven is located a few hundred metres from the residential area.Methods:The whole of Genoa and one of its 25 districts (Rivarolo) were selected as controls. The trend of risk around the coke oven was evaluated via Stone’s method, while the geographic pattern of such risks across the Cornigliano district was evaluated by computing full Bayes estimates of standardised incidence ratio (FBE-SIR).Results:In males, elevated relative risks (RR) were observed for all lymphohaematopoietic cancers (RR 1.7vRivarolo and 1.6vGenoa), for NHL (RR 2.4vRivarolo and 1.7vGenoa), and for leukaemia (RR 2.4vRivarolo and 1.9vGenoa). In females, statistically non-significant RR were observed. In males no excess of risk was found close to the coke oven. In females, a rising risk for NHL was observed approaching the plant, although statistical significance was not reached, while the risk for leukaemia was not evaluable due to the small number of cases. Analysis of the geographic pattern of risk suggested the presence of a cluster of NHL in both sexes in the eastern part of the district, where a foundry had been operational until the early 1980s. A cluster of leukaemia cases was observed in males in a northern part of the area, where no major sources of benzene seemed to be present.Conclusions:The estimated risks seem to be slightly or not at all related to the distance from the coke oven. The statistically significant higher risks observed in males for NHL and leukaemia, and the clusters of leukaemia in males and of NHL in both sexes deserve further investigations in order to trace the exposures associated with such risks.
Coverage of work related fatalities in Australia by compensation and occupational health and safety agencies
Authors: Driscoll T , Mitchell R , Mandryk J , Healey S , Hendrie L , Hull B 
Published: February 2003

Aims:To determine the levels of coverage of work related traumatic deaths by official occupational health and safety (OHS) and compensation agencies in Australia, to allow better understanding and interpretation of officially available statistics.Methods:The analysis was part of a much larger study of all work related fatalities that occurred in Australia during the four year period 1989 to 1992 inclusive and which was based on information from coroners’ files. For the current study, State, Territory, and Commonwealth OHS and compensation agencies were asked to supply unit record information for all deaths identified by the jurisdictions as being due to non-suicide traumatic causes and which were identified by them as being work related, using whatever definitions the agencies were using at the relevant time. This information was matched to cases identified during the main study.Results:The percentage of working deaths not covered by any agency was 34%. Only 35% of working deaths were covered by an OHS agency, while 57% were covered by a compensation agency. The OHS agencies had minimal coverage of work related deaths that occurred on the road (to workers (8%) or commuters (3%)), whereas the compensation system covered these deaths better than those of workers in incidents that occurred in a workplace (65% versus 53%). There was virtually no coverage of bystanders (less than 8%) by either type of agency. There was marked variation in the level of coverage depending on the industry, occupation, and employment status of the workers, and the type of injury event involved in the incident.Conclusions:When using data from official sources, the significant limitations in coverage identified in this paper need to be taken into account. Future surveillance, arising from a computerised National Coroners Information System, should result in improved coverage of work related traumatic deaths in Australia.
Radiographic (ILO) readings predict arterial oxygen desaturation during exercise in subjects with asbestosis
Authors: Lee Y C G , Singh B , Pang S C , de Klerk N H , Hillman D R , Musk A W 
Published: February 2003

Background:Exercise impairment is common in subjects with asbestosis. Arterial oxygen desaturation during exercise is an important contributor to exercise limitation. The International Labour Office (ILO) classification of plain chest radiographs correlates with resting pulmonary function, but its value in predicting abnormal ventilatory responses to exercise, including desaturation, has not been explored.Aims:To determine in subjects with asbestosis (1) if radiographic profusion scores and the extent of small irregular shadows on plain chest radiographs correlate with resting lung function and abnormal ventilatory responses to exercise; and (2) if radiographic scores add value to resting lung function tests in predicting abnormal ventilatory responses to exercise.Methods:Thirty eight male subjects with asbestosis were included. Plain chest radiographs were read according to the ILO classification independently by three observers. All subjects underwent assessment of lung function and an incremental exercise test.Results:Profusion scores and number of affected zones correlated significantly with the percentage predicted values of single breath diffusing capacity (DLCO), forced vital capacity (FVC), and total lung capacity (TLC). Arterial oxygen desaturation occurred in 29% of the subjects. The severity of desaturation correlated significantly with profusion and the number of affected zones. The combined use of number of affected zones, FEV1/FVC ratio and DLCO predicted desaturation during exercise with an explained variance of 41%. VO2max was significantly related only to DLCO but was not predicted by the ILO score.Conclusion:Arterial oxygen desaturation correlated with the profusion and extent of parenchymal abnormality on chest radiographs. The addition of morphological indices to physiological measurements is valuable for predicting oxygen desaturation during exercise but not for VO2max. Refinement of the radiographic scoring system and the addition of more sophisticated imaging techniques may further improve the predictive power.
Volcanic ash and respiratory symptoms in children on the island of Montserrat, British West Indies
Authors: Forbes L , Jarvis D , Potts J , Baxter P J 
Published: February 2003

Background:In July 1995 the volcano on the West Indian island of Montserrat erupted after being inactive for several hundred years. Since then, clouds of ash have been released intermittently from the volcano. Some of this ash is <10 μm in diameter and therefore respirable. Concerns were raised that the particles might cause respiratory problems.Aims:To evaluate whether ashfalls had any effect on the respiratory health of children in Montserrat.Methods:A survey of asthma diagnoses, respiratory symptoms, exercise induced bronchoconstriction (EIB), and current and previous exposure to volcanic ash was carried out in schools in Montserrat during February 1998.Results:Questionnaire information was available for nearly 80% of the 443 children on the school rolls. The prevalence of wheeze symptoms in the previous 12 months was 18% in children aged 12 years and under and 16% in children aged 13 years and over. In children aged 12 and under, the prevalence of wheeze was greater in those who had ever been heavily or moderately exposed to volcanic ash compared with the group who had only ever been exposed to low levels (wheeze in last 12 months: odds ratio (OR) 4.30; wheeze ever: OR 3.45). The prevalence of EIB in 8–12 year olds was about four times higher in those who were currently heavily exposed to volcanic ash (OR 3.85) compared to those currently exposed to low levels.Conclusions:Volcanic ash emissions adversely affected the respiratory health of Montserrat children. The findings emphasise the need to limit exposures of children to volcanic ash and ensure the appropriate management of respiratory symptoms.
Memory one month after acute carbon monoxide intoxication: a prospective study
Authors: Deschamps D , Géraud C , Julien H , Baud F J , Dally S 
Published: February 2003

Background:Serious delayed neuropsychological sequelae may complicate carbon monoxide intoxication. The existence of minor manifestations, especially memory disturbances, is not well documented.Aims:To study several memory functions after carbon monoxide intoxication.Methods:In a prospective study, 32 poisoned patients without risk factors for cognitive disturbances were compared to 32 paired control subjects one month after acute carbon monoxide intoxication (blood carbon monoxide concentration at least 1.0 mmol/l), who had been treated with standard conventional therapy. Psychometric tests included Buschke’s verbal memory testing, verbal digit span, Corsi’s visuospatial span, reaction times, Stroop’s colours decoding test, and verbal fluency test.Results:(1) Memory functions in poisoned subjects were not worse than in the control group and were even better in some areas: learning, word recall, and quality of learning by Buschke’s verbal memory testing. Attention was also better in the patients, in whom visual reaction time was shorter than in controls. (2) Results of several memory functions—quality of learning and immediate visual memory—were positively correlated with the initial carbon monoxide level.Conclusions:In a highly selected subset of patients devoid of risk factors for memory impairment, memory, objectively evaluated by psychometric testing, was not worse one month after carbon monoxide intoxication in patients undergoing standard treatment than in paired control subjects.
Pain tolerance in upper limb disorders: findings from a community survey
Authors: Mitchell S , Reading I , Walker-Bone K , Palmer K , Cooper C , Coggon D 
Published: February 2003

Aims:To test the hypothesis that non-specific upper limb pain arises from altered pain perception with reduced tolerance of sensory stimuli.Methods:Subjects undergoing clinical examination as part of a community based survey of upper limb disorders were invited to return for an assessment of pain tolerance. A standardised algorithm was used to classify the 94 participants according to whether they had specific upper limb disorders (n = 22), non-specific arm pain (n = 15), or no arm pain (n = 57). Pain tolerance was assessed at three anatomical sites in each arm in response to electrocutaneous stimulation with alternating currents up to a maximum of 10 mA at three frequencies (5, 250, and 2000 Hz). A proportional odds model was used to compare pain tolerance thresholds according to sex, age, and diagnosis.Results:Women were less tolerant of pain than men (OR 0.13) and tolerance also declined with age (OR for one year increase in age 0.97). After allowance for sex and age, there was no indication that pain tolerance was lower in subjects with non-specific arm pain than in those with specific upper limb disorders or those who had no arm pain.Conclusions:The study hypothesis was not supported. However, before the hypothesis is dismissed, it should be tested further in patients with more severe and disabling arm pain.