bluuebunny/crossref_metadata_2025 huggingface dataset:
Antecedents of adult wellbeing: adolescent religiosity and health
Authors: Martin Terence , Kirkcaldy Bruce , Siefen Georg
Published: July 2003

An extant of literature has demonstrated an apparent connection between religiosity and physical and psychological health, yet there is a scarcity of studies focussing on the impact of religion on health among children and adolescents. The current study examined associations between self‐report data on self‐image, physical and psychological health and death‐related cognitions in a large representative sample of German high‐school students. Almost 1,000 German adolescents (aged 14‐18 years) were administered a comprehensive series of questionnaires aimed at assessing anxiety/depression, trait addiction, smoking and drinking behaviour, physical ill‐health reports, and self‐perception of self‐image, parental acceptance and educational attainment. Several statements were incorporated to assess self‐injury and suicidal ideation. Just over half of the adolescents (56.9 per cent) did not attend church at all. Level of school influenced church attendance with secondary school adolescents attending least. Religious denomination also exerted a major role on church attendance with Muslims attending most regularly followed by Roman Catholics and then Protestants. Males were more likely to be non‐attendees. Regular church attendees tended to adopt more healthy life‐styles, they exercised more regularly, smoked less, were more likely to display higher school grades in linguistic – but not mathematical – competency. Conversely, there was some indication that negative affect, reflected by higher scores on the social problems scale was higher among church attenders. Religiosity was scarcely related to suicidal ideation among adolescents.
Seeking success through strategic management development
Authors: Brown Paul
Published: July 2003

Strategic management development (SMD) uses corporate objectives and strategies as drivers for management development and aims to achieve multiple outcomes. Most studies of SMD have concentrated on consultant‐ or practitioner‐based accounts of “best practice”. There has been little development of conceptual frameworks to inform a more rigorous understanding and evaluation of SMD. Considers the usefulness of some existing frameworks and then, based on literature review and synthesis, proposes new conceptual frameworks for SMD. The first of these new frameworks explores the relationships between individual and organisational objectives in the SMD processes. Many management development interventions have both types of objective and other interventions may be more polarised in purpose. These tensions have to be resolved at the level of the individual manager. Because of environmental change account will need to be taken of emergent needs and opportunities. The second framework reflects this showing how a dynamic environment will lead to more organic forms of management development. The third framework considers the barriers and drivers influencing SMD, and proposes the key requirements for success.
Managerial values in local government – Victoria, Australia
Authors: Pullin Len , Haidar Ali
Published: July 2003

This article explores the values that local government senior managers assume in their day‐to‐day relationship with elected officials (councillors). The study is set in the state of Victoria, Australia which, along with the two other levels of Australian government, has a strong historical association with the Westminster system of public management. The findings demonstrate that local government senior managers practice the fundamental values and beliefs of public management neutrality.
The impact on officials of public sector restructuring
Authors: Gauld Robin
Published: July 2003

There has been limited examination of the impact of public sector restructuring on affected officials. This paper seeks to address the imbalance. It discusses the case of the New Zealand Health Funding Authority, dissolved and merged in 2000 as part of a major health sector restructuring programme. The paper overviews literature on change management and organisational mergers, outlines New Zealand's succession of public health sector changes through the 1990s, and details the procedures involved in the health funding authority restructuring. The impact on senior health funding authority staff and their impressions of the change process studied through the lens of a survey conducted in August 2000 are discussed, along with lessons from the New Zealand case.
Research in spirituality, religion, and work
Authors: Lund Dean Kathy , Fornaciari Charles J. , McGee James J.
Published: July 2003

While spirituality and religion in work (SRW) as an inquiry field has been gaining interest in the popular press, it has only recently been recognized by the academic community. Consequently, its relevance to important research and its legitimacy in contributing scholarly work is not ensured. Part of the problem is that many SRW concepts resist being tested with “approved” positivist research models. This paper explores the tension between relevance and legitimacy, focusing on research methods, models, and traditions that may serve both well. It suggests that many methodologies and traditions that support such work already exist. It discusses some of these methods and offers operational blueprints for alternative forms of excellent research. It argues that combining such methodological underpinnings with experimental models and new forms of data representation allows for scholarly work to emerge, thus facilitating SRW's desire to stay true to important research questions while respecting sound research traditions.
Comparing spirituality on three southern California college campuses
Authors: Bradley Jaqui , King Kauanui Sandra
Published: July 2003

Following September 11, 2001, spirituality has become an even more important issue. Research projects have been done to address the need of spirituality in the corporate workplace. The issue of spirituality in the academic workplace is even more vital since it is from within the higher academic institutions that the leaders of tomorrow emerge. Yet, little has been done. This research is an attempt to fulfill this need. This project examined the spirituality of professors and the spiritual culture found in a private secular college, a private Christian college and a state university, all located in southern California. The design of the research was based on the work of Ian Mitroff and Parker Palmer. The results showed that there was a difference in the spiritual culture between these three campuses and that the spirituality of the professors was a reflection of the spiritual culture found on the campuses.
Purification and Characterization of a Novel Erythrose Reductase from
Candida magnoliae
Authors: Lee Jung-Kul , Kim Sang-Yong , Ryu Yeon-Woo , Seo Jin-Ho , Kim Jung-Hoe
Published: July 2003

Erythritol biosynthesis is catalyzed by erythrose reductase, which converts erythrose to erythritol. Erythrose reductase, however, has never been characterized in terms of amino acid sequence and kinetics. In this study, NAD(P)H-dependent erythrose reductase was purified to homogeneity from
Candida magnoliae
KFCC 11023 by ion exchange, gel filtration, affinity chromatography, and preparative electrophoresis. The molecular weights of erythrose reductase determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography were 38,800 and 79,000, respectively, suggesting that the enzyme is homodimeric. Partial amino acid sequence analysis indicates that the enzyme is closely related to other yeast aldose reductases.
C. magnoliae
erythrose reductase catalyzes the reduction of various aldehydes. Among aldoses, erythrose was the preferred substrate (
K

m

= 7.9 mM;
k
cat
/
K

m

= 0.73 mM
−1
s
−1
). This enzyme had a dual coenzyme specificity with greater catalytic efficiency with NADH (
k
cat
/
K

m

= 450 mM
−1
s
−1
) than with NADPH (
k
cat
/
K

m

= 5.5 mM
−1
s
−1
), unlike previously characterized aldose reductases, and is specific for transferring the 4-
pro-R
hydrogen of NADH, which is typical of members of the aldo/keto reductase superfamily. Initial velocity and product inhibition studies are consistent with the hypothesis that the reduction proceeds via a sequential ordered mechanism. The enzyme required sulfhydryl compounds for optimal activity and was strongly inhibited by Cu
2+
and quercetin, a strong aldose reductase inhibitor, but was not inhibited by aldehyde reductase inhibitors and did not catalyze the reduction of the substrates for carbonyl reductase. These data indicate that the
C. magnoliae
erythrose reductase is an NAD(P)H-dependent homodimeric aldose reductase with an unusual dual coenzyme specificity.
Characterization and In Situ Carbon Metabolism of Phototrophic Consortia
Authors: Glaeser Jens , Overmann Jörg
Published: July 2003

A dense population of the phototrophic consortium “
Pelochromatium roseum
” was investigated in the chemocline of a temperate holomictic lake (Lake Dagow, Brandenburg, Germany). Fluorescence in situ hybridization revealed that the brown epibionts of “
P. roseum
” constituted up to 37% of the total bacterial cell number and up to 88% of all green sulfur bacteria present in the chemocline. Specific amplification of 16S rRNA gene fragments of green sulfur bacteria and denaturing gradient gel electrophoresis fingerprinting yielded a maximum of four different DNA bands depending on the year of study, indicating that the diversity of green sulfur bacteria was low. The 465-bp 16S rRNA gene sequence of the epibiont of “
P. roseum
” was obtained after sorting of individual consortia by micromanipulation, followed by a highly sensitive PCR. The sequence obtained represents a new phylotype within the radiation of green sulfur bacteria. Maximum light-dependent H
14
CO
3
−
fixation in the chemocline in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea suggested that there was anaerobic autotrophic growth of the green sulfur bacteria. The metabolism of the epibionts was further studied by determining stable carbon isotope ratios (δ
13
C) of their specific biomarkers. Analysis of photosynthetic pigments by high-performance liquid chromatography revealed the presence of high concentrations of bacteriochlorophyll (BChl)
e
and smaller amounts of BChl
a
and
d
and chlorophyll
a
in the chemocline. Unexpectedly, isorenieratene and β-isorenieratene, carotenoids typical of other brown members of the green sulfur bacteria, were absent. Instead, four different esterifying alcohols of BChl
e
were isolated as biomarkers of green sulfur bacterial epibionts, and their δ
13
C values were determined. Farnesol, tetradecanol, hexadecanol, and hexadecenol all were significantly enriched in
13
C compared to bulk dissolved and particulate organic carbon and compared to the biomarkers of purple sulfur bacteria. The difference between the δ
13
C values of farnesol, the major esterifying alcohol of BChl
e
, and CO
2
was −7.1%, which provides clear evidence that the mode of growth of the green sulfur bacterial epibionts of “
P. roseum
” in situ is photoautotrophic.
Dynamics of Fungal Communities in Bulk and Maize Rhizosphere Soil in the Tropics
Authors: Gomes Newton C. Marcial , Fagbola Olajire , Costa Rodrigo , Rumjanek Norma Gouvea , Buchner Arno , Mendona-Hagler Leda , Smalla Kornelia
Published: July 2003

The fungal population dynamics in soil and in the rhizospheres of two maize cultivars grown in tropical soils were studied by a cultivation-independent analysis of directly extracted DNA to provide baseline data. Soil and rhizosphere samples were taken from six plots 20, 40, and 90 days after planting in two consecutive years. A 1.65-kb fragment of the 18S ribosomal DNA (rDNA) amplified from the total community DNA was analyzed by denaturing gradient gel electrophoresis (DGGE) and by cloning and sequencing. A rhizosphere effect was observed for fungal populations at all stages of plant development. In addition, pronounced changes in the composition of fungal communities during plant growth development were found by DGGE. Similar types of fingerprints were observed in two consecutive growth periods. No major differences were detected in the fungal patterns of the two cultivars. Direct cloning of 18S rDNA fragments amplified from soil or rhizosphere DNA resulted in 75 clones matching 12 dominant DGGE bands. The clones were characterized by their
Hin
fI restriction patterns, and 39 different clones representing each group of restriction patterns were sequenced. The cloning and sequencing approach provided information on the phylogeny of dominant amplifiable fungal populations and allowed us to determine a number of fungal phylotypes that contribute to each of the dominant DGGE bands. Based on the sequence similarity of the 18S rDNA fragment with existing fungal isolates in the database, it was shown that the rhizospheres of young maize plants seemed to select the Ascomycetes order Pleosporales, while different members of the Ascomycetes and basidiomycetic yeast were detected in the rhizospheres of senescent maize plants.
Effects of Litter Addition on Ectomycorrhizal Associates of a Lodgepole Pine (
Pinus contorta
) Stand in Yellowstone National Park
Authors: Cullings Kenneth W. , New Michael H. , Makhija Shilpa , Parker V. Thomas
Published: July 2003

Increasing soil nutrients through litter manipulation, pollution, or fertilization can adversely affect ectomycorrhizal (EM) communities by inhibiting fungal growth. In this study, we used molecular genetic methods to determine the effects of litter addition on the EM community of a
Pinus contorta
stand in Yellowstone National Park that regenerated after a stand-replacing fire. Two controls were used; in unmodified control plots nothing was added to the soil, and in perlite plots perlite, a chemically neutral substance, was added to maintain soil moisture and temperature at levels similar to those under litter. We found that (i) species richness did not change significantly following perlite addition (2.6 ± 0.3 species/core in control plots, compared with 2.3 ± 0.3 species/core in perlite plots) but decreased significantly (
P
< 0.05) following litter addition (1.8 ± 0.3 species/core); (ii) EM infection was not affected by the addition of perlite but increased significantly (
P
< 0.001) in response to litter addition, and the increase occurred only in the upper soil layer, directly adjacent to the added litter; and (iii)
Suillus granulatus
,
Wilcoxina mikolae
, and agaricoid DD were the dominant organisms in controls, but the levels of
W. mikolae
and agaricoid DD decreased significantly in response to both perlite and litter addition. The relative levels of
S. granulatus
and a fourth fungus, Cortinariaceae species 2, increased significantly (
P
< 0.01 and
P
< 0.05, respectively) following litter addition. Thus, litter addition resulted in some negative effects that may be attributable to moisture-temperature relationships rather than to the increased nutrients associated with litter. Some species respond positively to litter addition, indicating that there are differences in their physiologies. Hence, changes in the EM community induced by litter accumulation also may affect ecosystem function.
Construction of an Expression System for Site-DirectedMutagenesis of the LantibioticMersacidin
Authors: Szekat Christiane , Jack Ralph W. , Skutlarek Dirk , Färber Harald , Bierbaum Gabriele
Published: July 2003

The
lantibiotic (i.e., lanthionine-containing antibiotic) mersacidin is an
antimicrobial peptide of 20 amino acids which is produced by
Bacillus
sp. strain HIL Y-85,54728. Mersacidin inhibits
bacterial cell wall biosynthesis by binding to the precursor molecule
lipid II. The structural gene of mersacidin (
mrsA
) and the
genes for the enzymes of the biosynthesis pathway, dedicated
transporters, producer self-protection proteins, and regulatory factors
are organized in a biosynthetic gene cluster. For
site-directed mutagenesis of lantibiotics, the engineered genes must be
expressed in an expression system that contains all of the factors
necessary for biosynthesis, export, and producer self-protection. In
order to express engineered mersacidin peptides, a system in which the
engineered gene replaces the wild-type gene on the chromosome was
constructed. To test the expression system, three mutants were
constructed. In S16I mersacidin, the didehydroalanine residue (Dha) at
position 16 was replaced with the Ile residue found in the closely
related lantibiotic actagardine. S16I mersacidin was produced only in
small amounts. The purified peptide had markedly reduced antimicrobial
activity, indicating an essential role for Dha16 in biosynthesis and
biological activity of mersacidin. Similarly, Glu17, which is thought
to be an essential structure in mersacidin, was exchanged for alanine.
E17A mersacidin was obtained in good yields but also showed markedly
reduced activity, thus confirming the importance of the carboxylic acid
function at position 17 in the biological activity of mersacidin.
Finally, the exchange of an aromatic for an aliphatic hydrophobic
residue at position 3 resulted in the mutant peptide F3L mersacidin;
this peptide showed only moderately reduced
activity.
Freshwater Bacteria Can Methylate Selenium through the Thiopurine Methyltransferase Pathway
Authors: Ranjard Lionel , Nazaret Sylvie , Cournoyer Benoit
Published: July 2003

Involvement of the bacterial thiopurine methyltransferase (bTPMT) in natural selenium methylation by freshwater was investigated. A freshwater environment that had no known selenium contamination but exhibited reproducible emission of dimethyl selenide (DMSe) or dimethyl diselenide (DMDSe) when it was supplemented with an organic form of selenium [(methyl)selenocysteine] or an inorganic form of selenium (sodium selenite) was used. The distribution of the bTPMT gene (
tpm
) in the microflora was studied. Freshwater bacteria growing on 10 μM sodium selenite and 10 μM sodium selenate were isolated, and 4.5 and 10% of the strains, respectively, were shown by colony blot hybridization to hybridize with a
Pseudomonas syringae tpm
DNA probe. Ribotyping showed that these strains are closely related. The complete
rrs
sequence of one of the strains, designated Hsa.28, was obtained and analyzed. Its closest phyletic neighbor was found to be the
Pseudomonas anguilliseptica rrs
sequence. The Hsa.28 strain grown with sodium selenite or (methyl)selenocysteine produced significant amounts of DMSe and DMDSe. The Hsa.28
tpm
gene was isolated by genomic DNA library screening and sequencing. BLASTP comparisons of the deduced Hsa.28 bTPMT sequence with
P. syringae
,
Pseudomonas aeruginosa
,
Vibrio cholerae
, rat, and human thiopurine methyltransferase sequences revealed that the levels of similarity were 52 to 71%. PCR-generated
Escherichia coli
subclones containing the Hsa.28
tpm
open reading frame were constructed.
E. coli
cells harboring the constructs and grown with sodium selenite or (methyl)selenocysteine produced significant levels of DMSe and DMDSe, confirming that the gene plays a role in selenium methylation. The effect of strain Hsa.28 population levels on freshwater DMSe and DMDSe emission was investigated. An increase in the size of the Hsa.28 population was found to enhance significantly the emission of methyl selenides by freshwater samples supplemented with sodium selenite or (methyl)selenocysteine. These data suggest that bTPMT can play a role in natural freshwater selenium methylation processes.
Determination of In Situ Bacterial Growth Rates in Aquifers and Aquifer Sediments
Authors: Mailloux Brian J. , Fuller Mark E.
Published: July 2003

Laboratory and field-scale studies with stained cells were performed to monitor cell growth in groundwater systems. During cell division, the fluorescence intensity of the protein stain 5-(and 6-)-carboxyfluorescein diacetate succinimidyl ester (CFDA/SE) for each cell is halved, and the intensity can be tracked with a flow cytometer. Two strains of bacteria,Comamonassp. strain DA001 andAcidovoraxsp. strain OY-107, both isolated from a shallow aquifer, were utilized in this study. The change in the average generation or the average fluorescence intensity of the CFDA/SE-stained cells could be used to obtain estimates of doubling times. In microcosm experiments, the CFDA/SE-based doubling times were similar to the values calculated by total cell counting and were independent of cell concentration. Intact and repacked sediment core experiments with the same bacteria indicated that changes in groundwater chemistry were just as important as growth rates in determining planktonic cell concentrations. The growth rates within the sediment cores were similar to those calculated in microcosm experiments, and preferential transport of the daughter cells was not observed. The experiments indicated that the growth rates could be determined in systems with cell losses due to other phenomena, such as attachment to sediment or predation. Application of this growth rate estimation method to data from a field-scale bacterial transport experiment indicated that the doubling time was approximately 15 days, which is the first known direct determination of an in situ growth rate for bacteria in an aquifer.
Susceptibility and Adaptive Response to Bile Salts in
Propionibacterium freudenreichii
: Physiological and Proteomic Analysis
Authors: Leverrier Pauline , Dimova Diliana , Pichereau Vianney , Auffray Yanick , Boyaval Patrick , Jan Gwénaël
Published: July 2003

Tolerance to digestive stresses is one of the main factors limiting the use of microorganisms as live probiotic agents. Susceptibility to bile salts and tolerance acquisition in the probiotic strain
Propionibacterium freudenreichii
SI41 were characterized. We showed that pretreatment with a moderate concentration of bile salts (0.2 g/liter) greatly increased its survival during a subsequent lethal challenge (1.0 g/liter, 60 s). Bile salts challenge led to drastic morphological changes, consistent with intracellular material leakage, for nonadapted cells but not for preexposed ones. Moreover, the physiological state of the cells during lethal treatment played an important role in the response to bile salts, as stationary-phase bacteria appeared much less sensitive than exponentially growing cells. Either thermal or detergent pretreatment conferred significantly increased protection toward bile salts challenge. In contrast, some other heterologous pretreatments (hypothermic and hyperosmotic) had no effect on tolerance to bile salts, while acid pretreatment even might have sensitized the cells. Two-dimensional electrophoresis experiments revealed that at least 24 proteins were induced during bile salts adaptation. Identification of these polypeptides suggested that the bile salts stress response involves signal sensing and transduction, a general stress response (also triggered by thermal denaturation, oxidative toxicity, and DNA damage), and an alternative sigma factor. Taken together, our results provide new insights into the tolerance of
P. freudenreichii
to bile salts, which must be taken into consideration for the use of probiotic strains and the improvement of technological processes.
Influence of Surface Characteristics on the Stability of
Cryptosporidium parvum
Oocysts
Authors: Butkus Michael A. , Bays J. Timothy , Labare Michael P.
Published: July 2003

Microelectrophoresis is a common technique for probing the surface chemistry of the
Cryptosporidium parvum
oocyst. Results of previous studies of the electrophoretic mobility of
C. parvum
oocysts in which microelectrophoresis was used are incongruent. In this work we demonstrated that capillary electrophoresis may also be used to probe the surface characteristics of
C. parvum
oocysts, and we related the surface chemistry of
C. parvum
oocysts to their stability in water. Capillary electrophoresis results indicated that oocysts which were washed in a phosphate buffer solution had neutrally charged surfaces. Inactivation of oocysts with formalin did not influence their electrophoretic mobility, while oocyst populations that were washed in distilled water consisted of cells with both neutral and negative surface charges. These results indicate that washing oocysts in low-ionic-strength distilled water can impart a negative charge to a fraction of the oocysts in the sample. Rapid coagulation experiments indicated that oocysts did not aggregate in a 0.5 M NaCl solution; oocyst stability in the salt solution may have been the result of Lewis acid-base forces, steric stabilization, or some other factor. The presence of sucrose and Percoll could not be readily identified on the surface of
C. parvum
oocysts by attenuated total reflectance-Fourier transform infrared spectroscopy, suggesting that these purification reagents may not be responsible for the stability of the uncharged oocysts. These findings imply that precipitate enmeshment may be the optimal mechanism of coagulation for removal of oocysts in water treatment systems. The results of this work may help elucidate the causes of variation in oocyst surface characteristics, may ultimately lead to improved removal efficiencies in full-scale water treatment systems, and may improve fate and transport predictions for oocysts in natural systems.
Production of Novel Tetrahydroxyfuranyl Fatty Acids from α-Linolenic Acid by
Clavibacter
sp. Strain ALA2
Authors: Hosokawa Masashi , Hou Ching T. , Weisleder David
Published: July 2003

Previously, it was reported that a newly isolated microbial culture,
Clavibacter
sp. strain ALA2, produced trihydroxy unsaturated fatty acids, diepxoy bicyclic fatty acids, and tetrahydroxyfuranyl fatty acids (THFAs) from linoleic acid (C. T. Hou, J. Am. Oil Chem. Soc. 73:1359-1362, 1996; C. T. Hou and R. J. Forman III, J. Ind. Microbiol. Biotechnol. 24:275-276, 2000; C. T. Hou, H. Gardner, and W. Brown, J. Am. Oil Chem. Soc. 75:1483-1487, 1998; C. T. Hou, H. W. Gardner, and W. Brown, J. Am. Oil Chem. Soc. 78:1167-1169, 2001). In this study, we found that
Clavibacter
sp. strain ALA2 produced novel THFAs, including 13,16-dihydroxy-12-THFA, 15-epoxy-9(
Z
)-octadecenoic acid (13,16-dihydroxy-THFA), and 7,13,16-trihydroxy-12, 15-epoxy-9(
Z
)-octadecenoic acid (7,13,16-trihydroxy-THFA), from α-linolenic acid (9,12,15-octadecatrienoic acid). The chemical structures of these products were determined by gas chromatography-mass spectrometry and proton and
13
C nuclear magnetic resonance analyses. The optimum incubation temperature was 30°C for production of both hydroxy-THFAs. 13,16-Dihydroxy-THFA was detected after 2 days of incubation, and the concentration reached 45 mg/50 ml after 7 days of incubation; 7,13,16-trihydroxy-THFA was not detected after 2 days of incubation, but the concentration reached 9 mg/50 ml after 7 days of incubation. The total yield of both 13,16-dihydroxy-THFA and 7,13,16-trihydroxy-THFA was 67% (wt/wt) after 7 days of incubation at 30°C and 200 rpm. In previous studies, it was reported that
Clavibacter
sp. strain ALA2 oxidized the C-7, C-12, C-13, C-16, and C-17 positions of linoleic acid (n-6) into hydroxy groups. In this case, the bond between the C-16 and C-17 carbon atoms is saturated. In α-linolenic acid (n-3), however, the bond between the C-16 and C-17 carbon atoms is unsaturated. It seems that enzymes of strain ALA2 oxidized the C-12-C-13 and C-16-C-17 double bonds into dihydroxy groups first and then converted them to hydroxy-THFAs.
Isolation of Tetracycline-Resistant
Megasphaera elsdenii
Strains with Novel Mosaic Gene Combinations of
tet
(O) and
tet
(W) from Swine
Authors: Stanton Thaddeus B. , Humphrey Samuel B.
Published: July 2003

Anaerobic bacteria insensitive to chlortetracycline (64 to 256 μg/ml) were isolated from cecal contents and cecal tissues of swine fed or not fed chlortetracycline. A nutritionally complex, rumen fluid-based medium was used for culturing the bacteria. Eight of 84 isolates from seven different animals were identified as
Megasphaera elsdenii
strains based on their large-coccus morphology, rapid growth on lactate, and 16S ribosomal DNA sequence similarities with
M. elsdenii
LC-1
T
. All eight strains had tetracycline MICs of between 128 and 256 μg/ml. Based on PCR assays differentiating 14
tet
classes, the strains gave a positive reaction for the
tet
(O) gene. By contrast, three ruminant
M. elsdenii
strains recovered from 30-year-old culture stocks had tetracycline MICs of 4 μg/ml and did not contain
tet
genes. The
tet
genes of two tetracycline-resistant
M. elsdenii
strains were amplified and cloned. Both genes bestowed tetracycline resistance (MIC = 32 to 64 μg/ml) on recombinant
Escherichia coli
strains. Sequence analysis revealed that the
M. elsdenii
genes represent two different mosaic genes formed by interclass (double-crossover) recombination events involving
tet
(O) and
tet
(W). One or the other genotype was present in each of the eight tetracycline-resistant
M. elsdenii
strains isolated in these studies. These findings suggest a role for commensal bacteria not only in the preservation and dissemination of antibiotic resistance in the intestinal tract but also in the evolution of resistance.
Anaerobic Transformation of Alkanes to Fatty Acids by a Sulfate-Reducing Bacterium, Strain Hxd3
Authors: So Chi Ming , Phelps Craig D. , Young L. Y.
Published: July 2003

Strain Hxd3, an alkane-degrading sulfate reducer previously isolated and described by Aeckersberg et al. (F. Aeckersberg, F. Bak, and F. Widdel, Arch. Microbiol. 156:5-14, 1991), was studied for its alkane degradation mechanism by using deuterium and
13
C-labeled compounds. Deuterated fatty acids with even numbers of C atoms (C-even) and
13
C-labeled fatty acids with odd numbers of C atoms (C-odd) were recovered from cultures of Hxd3 grown on perdeuterated pentadecane and [1,2-
13
C
2
]hexadecane, respectively, underscoring evidence that C-odd alkanes are transformed to C-even fatty acids and vice versa. When Hxd3 was grown on unlabeled hexadecane in the presence of [
13
C]bicarbonate, the resulting 15:0 fatty acid, which was one carbon shorter than the alkane, incorporated a
13
C label to form its carboxyl group. The same results were observed when tetradecane, pentadecane, and perdeuterated pentadecane were used as the substrates. These observations indicate that the initial attack of alkanes includes both carboxylation with inorganic bicarbonate and the removal of two carbon atoms from the alkane chain terminus, resulting in a fatty acid one carbon shorter than the original alkane. The removal of two terminal carbon atoms is further evidenced by the observation that the [1,2-
13
C
2
]hexadecane-derived fatty acids contained either two
13
C labels located exclusively at their acyl chain termini or none at all. Furthermore, when perdeuterated pentadecane was used as the substrate, the 14:0 and 16:0 fatty acids formed both carried the same numbers of deuterium labels, while the latter was not deuterated at its carboxyl end. These observations provide further evidence that the 14:0 fatty acid was initially formed from perdeuterated pentadecane, while the 16:0 fatty acid was produced after chain elongation of the former fatty acid with nondeuterated carbon atoms. We propose that strain Hxd3 anaerobically transforms an alkane to a fatty acid through a mechanism which includes subterminal carboxylation at the C-3 position of the alkane and elimination of the two adjacent terminal carbon atoms.
Degradation of Benzo[
a
]pyrene by the Litter-Decomposing Basidiomycete
Stropharia coronilla
: Role of Manganese Peroxidase
Authors: Steffen Kari T. , Hatakka Annele , Hofrichter Martin
Published: July 2003

The litter-decomposing basidiomycete
Stropharia coronilla
, which preferably colonizes grasslands, was found to be capable of metabolizing and mineralizing benzo[
a
]pyrene (BaP) in liquid culture. Manganese(II) ions (Mn
2+
) supplied at a concentration of 200 μM stimulated considerably both the conversion and the mineralization of BaP; the fungus metabolized and mineralized about four and twelve times, respectively, more of the BaP in the presence of supplemental Mn
2+
than in the basal medium. This stimulating effect could be attributed to the ligninolytic enzyme manganese peroxidase (MnP), whose activity increased after the addition of Mn
2+
. Crude and purified MnP from
S. coronilla
oxidized BaP efficiently in a cell-free reaction mixture (in vitro), a process which was enhanced by the surfactant Tween 80. Thus, 100 mg of BaP liter
−1
was converted in an in vitro reaction solution containing 1 U of MnP ml
−1
within 24 h. A clear indication was found that BaP-1,6-quinone was formed as a transient metabolite, which disappeared over the further course of the reaction. The treatment of a mixture of 16 different polycyclic aromatic hydrocarbons (PAHs) selected by the U.S. Environmental Protection Agency as model standards for PAH analysis (total concentration, 320 mg liter
−1
) with MnP resulted in concentration decreases of 10 to 100% for the individual compounds, and again the stimulating effect of Tween 80 was observed. Probably due to their lower ionization potentials, poorly bioavailable, high-molecular-mass PAHs such as BaP, benzo(
g
,
h
,
i
)perylene, and indeno(1,2,3-
c
,
d
)pyrene were converted to larger extents than low-molecular-mass ones (e.g., phenanthrene and fluoranthene).
Quantifying Mold Biomass on Gypsum Board: Comparison of Ergosterol and Beta-
N
-Acetylhexosaminidase as Mold Biomass Parameters
Authors: Reeslev M. , Miller M. , Nielsen K. F.
Published: July 2003

Two mold species,
Stachybotrys chartarum
and
Aspergillus versicolor
, were inoculated onto agar overlaid with cellophane, allowing determination of a direct measurement of biomass density by weighing. Biomass density, ergosterol content, and beta-
N
-acetylhexosaminidase (3.2.1.52) activity were monitored from inoculation to stationary phase. Regression analysis showed a good linear correlation to biomass density for both ergosterol content and beta-
N
-acetylhexosaminidase activity. The same two mold species were inoculated onto wallpapered gypsum board, from which a direct biomass measurement was not possible. Growth was measured as an increase in ergosterol content and beta-
N
-acetylhexosaminidase activity. A good linear correlation was seen between ergosterol content and beta-
N
-acetylhexosaminidase activity. From the experiments performed on agar medium, conversion factors (CFs) for estimating biomass density from ergosterol content and beta-
N
-acetylhexosaminidase activity were determined. The CFs were used to estimate the biomass density of the molds grown on gypsum board. The biomass densities estimated from ergosterol content and beta-
N
-acetylhexosaminidase activity data gave similar results, showing significantly slower growth and lower stationary-phase biomass density on gypsum board than on agar.
Temporal Stability and Biodiversity of Two Complex Antilisterial Cheese-Ripening Microbial Consortia
Authors: Maoz Ariel , Mayr Ralf , Scherer Siegfried
Published: July 2003

The temporal stability and diversity of bacterial species composition as well as the antilisterial potential of two different, complex, and undefined microbial consortia from red-smear soft cheeses were investigated. Samples were collected twice, at 6-month intervals, from each of two food producers, and a total of 400 bacterial isolates were identified by Fourier-transform infrared spectroscopy and 16S ribosomal DNA sequence analysis. Coryneform bacteria represented the majority of the isolates, with certain species being predominant. In addition,
Marinolactobacillus psychrotolerans
,
Halomonas venusta
,
Halomonas variabilis
,
Halomonas
sp. (10
6
to 10
7
CFU per g of smear), and an unknown, gram-positive bacterium (10
7
to 10
8
CFU per g of smear) are described for the first time in such a consortium. The species composition of one consortium was quite stable over 6 months, but the other consortium revealed less diversity of coryneform species as well as less stability. While the first consortium had a stable, extraordinarily high antilisterial potential in situ, the antilisterial activity of the second consortium was lower and decreased with time. The cause for the antilisterial activity of the two consortia remained unknown but is not due to the secretion of soluble, inhibitory substances by the individual components of the consortium. Our data indicate that the stability over time and a potential antilisterial activity are individual characteristics of the ripening consortia which can be monitored and used for safe food production without artificial preservatives.
Mutants and Intersexual Heterokaryons of
Blakeslea trispora
for Production of β-Carotene and Lycopene
Authors: Mehta Bina J. , Obraztsova Irina N. , Cerdá-Olmedo Enrique
Published: July 2003

The industrial production of β-carotene with the zygomycete
Blakeslea trispora
involves the joint cultivation of mycelia of opposite sex in the presence of β-ionone and other chemical activators. We have obtained improved strains by mutation and heterokaryosis. We chose wild strains on the basis of their growth and carotene content in single and mated cultures. Following exposure of their spores to
N
-methyl-
N
′-nitro-
N
-nitrosoguanidine, we obtained high-carotene mutants, which were more productive than their parents but similar to them in having β-carotene as the main product. Further increases in carotene content were obtained after a new round of mutagenesis in one of the mutants. The production was shifted to lycopene in cultures incubated in the presence of nicotine and in lycopene-rich mutants derived from the wild strains. The highest production levels were achieved in intersexual heterokaryons, which contained mutant nuclei of opposite sex. These contained up to 39 mg of β-carotene or 15 mg of lycopene per g (dry mass) under standard laboratory conditions in which the original wild strains contained about 0.3 mg of β-carotene per g (dry mass). β-Ionone did not increase the carotene content of these strains. Not all wild strains lent themselves to these improvements, either because they produced few mutants or because they did not increase their carotene production in mated cultures.
Toxicity of Al to
Desulfovibrio desulfuricans
Authors: Amonette J. E. , Russell C. K. , Carosino K. A. , Robinson N. L. , Ho J. T.
Published: July 2003

The toxicity of Al to
Desulfovibrio desulfuricans
G20 was assessed over a period of 8 weeks in a modified lactate C medium buffered at four initial pHs (5.0, 6.5, 7.2, and 8.3) and treated with five levels of added Al (0, 0.01, 0.1, 1.0, and 10 mM). At pH 5, cell population densities decreased significantly and any effect of Al was negligible compared to that of the pH. At pHs 6.5 and 7.2, the cell population densities increased by 30-fold during the first few days and then remained stable for soluble-Al concentrations of <5 × 10
−5
M. In treatments having total-Al concentrations of ≥1 mM, soluble-Al concentrations exceeded 5 × 10
−5
M and limited cell population growth substantially and proportionally. At pH 8.3, soluble-Al concentrations were below the 5 × 10
−5
M toxicity threshold and cell population density increases of 20- to 40-fold were observed. An apparent cell population response to added Al at pH 8.3 was attributed to the presence of large, spirilloidal bacteria (accounting for as much as 80% of the cells at the 10 mM added Al level). Calculations of soluble-Al speciation for the pH 6.5 and 7.2 treatments that showed Al toxicity suggested the possible presence of the Al
13
O
4
(OH)
24
(H
2
O)
12
7+
“tridecamer” cation and an inverse correlation of the tridecamer concentration and the cell population density. Analysis by
27
Al nuclear magnetic resonance spectroscopy, however, yielded no evidence of this species in freshly prepared samples or those taken 800 days after inoculation. Exclusion of the tridecamer species from the aqueous speciation calculations at pHs 6.5 and 7.2 yielded inverse correlations of the neutral Al(OH)
3
and anionic Al(OH)
4
−
monomeric species with cell population density, suggesting that one or both of these ions bear primary responsibility for the toxicity observed.
Contributions of Atmospheric CO and Hydrogen Uptake to Microbial Dynamics on Recent Hawaiian Volcanic Deposits
Authors: King Gary M.
Published: July 2003

A series of sites were established on Hawaiian volcanic deposits ranging from about 18 to 300 years old. Three sites occurred in areas that supported tropical rain forests; the remaining sites were in areas that supported little or no plant growth. Sites >26 years old consumed atmospheric CO and hydrogen at rates ranging from about 0.2 to 5 mg of CO m
−2
day
−1
and 0.1 to 4 mg of H
2
m
−2
day
−1
, respectively. Respiration, measured as CO
2
production, for a subset of the sites ranged from about 40 to >1,400 mg of CO
2
m
−2
day
−1
. CO and H
2
accounted for about 13 to 25% of reducing equivalent flow for all but a forested site, where neither substrate appeared significant. Based on responses to chloroform fumigation, hydrogen utilization appeared largely due to microbial uptake. In contrast to results for CO and hydrogen, methane uptake occurred consistently only at the forest site. Increasing deposit age was generally accompanied by increasing concentrations of organic matter and microbial biomass, measured as phospholipid phosphate. Exoenzymatic activities (acid and alkaline phosphatases and α- and β-glucosidases) were positively correlated with deposit age in spite of considerable variability within sites. The diversity of substrates utilized in Biolog Ecoplate assays also increased with deposit age, possibly reflecting changes in microbial community complexity.
Identification of a New Ribosomal Protection Type of Tetracycline Resistance Gene,
tet
(36), from Swine Manure Pits
Authors: Whittle Gabrielle , Whitehead Terence R. , Hamburger Nathan , Shoemaker Nadja B. , Cotta Michael A. , Salyers Abigail A.
Published: July 2003

Previously, only one ribosome protection type of a tetracycline resistance gene,
tetQ
, had been identified in
Bacteroides
spp. During an investigation of anaerobic bacteria present in swine feces and manure storage pits, a tetracycline-resistant
Bacteroides
strain was isolated. Subsequent analysis showed that this new
Bacteroides
strain,
Bacteroides
sp. strain 139, did not contain
tetQ
but contained a previously unidentified tetracycline resistance gene. Sequence analysis showed that the tetracycline resistance gene from
Bacteroides
sp. strain 139 encoded a protein (designated Tet 36) that defines a new class of ribosome protection types of tetracycline resistance. Tet 36 has 60% amino acid identity over 640 aa to TetQ and between 31 and 49% amino acid identity to the nine other ribosome protection types of tetracycline resistance genes. The
tet
(36) region was not observed to transfer from
Bacteroides
sp. strain 139 to another
Bacteroides
sp. under laboratory conditions. Yet
tet
(36) was found in other genera of bacteria isolated from the same swine manure pits and from swine feces. Phylogenetic analysis of the
tet
(36)-containing isolates indicated that
tet
(36) was present not only in the
Cytophaga-Flavobacter-Bacteroides
group to which
Bacteroides
sp. strain 139 belongs but also in gram-positive genera and gram-negative proteobacteria, indicating that horizontal transfer of
tet
(36) is occurring between these divergent phylogenetic groups in the farm environment.
Saprotrophic and Mycoparasitic Components of Aggressiveness of
Trichoderma harzianum
Groups toward the Commercial Mushroom
Agaricus bisporus
Authors: Williams Josie , Clarkson John M. , Mills Peter R. , Cooper Richard M.
Published: July 2003

We examined the mycoparasitic and saprotrophic behavior of isolates representing groups of
Trichoderma harzianum
to establish a mechanism for the aggressiveness towards
Agaricus bisporus
in infested commercial compost. Mycoparasitic structures were infrequently observed in interaction zones on various media, including compost, with cryoscanning electron microscopy.
T. harzianum
grows prolifically in compost in the absence or presence of
A. bisporus
, and the aggressive European (Th2) and North American (Th4) isolates produced significantly higher biomasses (6.8- and 7.5-fold, respectively) in compost than did nonaggressive, group 1 isolates. All groups secreted depolymerases that could attack the cell walls of
A. bisporus
and of wheat straw, and some were linked to aggressiveness. Growth on mushroom cell walls in vitro resulted in rapid production of chymoelastase and trypsin-like proteases by only the Th2 and Th4 isolates. These isolates also produced a dominant protease isoform (pI 6.22) and additional chitinase isoforms. On wheat straw, Th4 produced distinct isoforms of cellulase and laminarinase, but there was no consistent association between levels or isoforms of depolymerases and aggressiveness. Th3's distinctive profiles confirmed its reclassification as
Trichoderma atroviride.
Proteases and glycanases were detected for the first time in sterilized compost colonized by
T. harzianum
. Xylanase dominated, and some isoforms were unique to compost, as were some laminarinases. We hypothesize that aggressiveness results from competition, antagonism, or parasitism but only as a component of, or following, extensive saprotrophic growth involving degradation of wheat straw cell walls.
Quantum Dots as Strain- and Metabolism-Specific Microbiological Labels
Authors: Kloepfer J. A. , Mielke R. E. , Wong M. S. , Nealson K. H. , Stucky G. , Nadeau J. L.
Published: July 2003

Biologically conjugated quantum dots (QDs) have shown great promise as multiwavelength fluorescent labels for on-chip bioassays and eukaryotic cells. However, use of these photoluminescent nanocrystals in bacteria has not previously been reported, and their large size (3 to 10 nm) makes it unclear whether they inhibit bacterial recognition of attached molecules and whether they are able to pass through bacterial cell walls. Here we describe the use of conjugated CdSe QDs for strain- and metabolism-specific microbial labeling in a wide variety of bacteria and fungi, and our analysis was geared toward using receptors for a conjugated biomolecule that are present and active on the organism's surface. While cell surface molecules, such as glycoproteins, make excellent targets for conjugated QDs, internal labeling is inconsistent and leads to large spectral shifts compared with the original fluorescence, suggesting that there is breakup or dissolution of the QDs. Transmission electron microscopy of whole mounts and thin sections confirmed that bacteria are able to extract Cd and Se from QDs in a fashion dependent upon the QD surface conjugate.
Temperature-Regulated Bleaching and Lysis of the Coral
Pocillopora damicornis
by the Novel Pathogen
Vibrio coralliilyticus
Authors: Ben-Haim Yael , Zicherman-Keren Maya , Rosenberg Eugene
Published: July 2003

Coral bleaching is the disruption of symbioses between coral animals and their photosynthetic microalgal endosymbionts (zooxanthellae). It has been suggested that large-scale bleaching episodes are linked to global warming. The data presented here demonstrate that
Vibrio coralliilyticus
is an etiological agent of bleaching of the coral
Pocillopora damicornis
. This bacterium was present at high levels in bleached
P. damicornis
but absent from healthy corals. The bacterium was isolated in pure culture, characterized microbiologically, and shown to cause bleaching when it was inoculated onto healthy corals at 25°C. The pathogen was reisolated from the diseased tissues of the infected corals. The zooxanthella concentration in the bacterium-bleached corals was less than 12% of the zooxanthella concentration in healthy corals. When
P. damicornis
was infected with
V. coralliilyticus
at higher temperatures (27 and 29°C), the corals lysed within 2 weeks, indicating that the seawater temperature is a critical environmental parameter in determining the outcome of infection. A large increase in the level of the extracellular protease activity of
V. coralliilyticus
occurred at the same temperature range (24 to 28°C) as the transition from bleaching to lysis of the corals. We suggest that bleaching of
P. damicornis
results from an attack on the algae, whereas bacterium-induced lysis and death are promoted by bacterial extracellular proteases. The data presented here support the bacterial hypothesis of coral bleaching.