bluuebunny/crossref_metadata_2025_split huggingface dataset:
SECTORAL ELASTICITY OF SUBSTITUTION AND RETURNS TO SCALE IN SOUTH AFRICA
Authors: Gebreselasie Tewodros G. 
Published: October 2008

AbstractElasticity of substitution and returns to scale are estimated on a sectoral basis for South Africa using panel‐based generalised least square procedure. Apart from sectoral differences in terms of elasticity of substitution, the study found that elasticity of substitution is below unity in all of the sectors. Most of the sectors studied are found to have increasing returns to scale in production. The study further explores the implications of elasticity of factor substitution and returns to scale on growth and employment creation. It is argued that a greater number of jobs can be created from growth of sectors with constant or decreasing returns to scale than from the same level of output growth generated by sectors with increasing returns to scale. This is the case when the employment‐creating potential of the same amount of additional output is compared in all the sectors examined. By virtue of scale economies, a sector like finance, insurance, real estate and business services generates more output with less proportional increase in inputs, which means growth in this sector may not have the desired impact on job creation. However, given the sector's large share (20%) of the country's total output and employment, it may generate more jobs, even if sectors like utilities and construction experience the same level of output growth. Given its importance for growth and employment, the study recommends further investigation into the reasons why elasticity of substitution is lower in sectors like utilities, mining and trade, catering and accommodation services.
THE CONTRIBUTIONS OF MANUFACTURING AND SERVICES TO EMPLOYMENT CREATION AND GROWTH IN SOUTH AFRICA
Authors: Tregenna Fiona 
Published: October 2008

AbstractThis study examines the linkages between the manufacturing and services sectors, and between each of them and the rest of the domestic economy, based on analysis of input‐output tables and employment trends. This reveals that manufacturing is particularly important as a source of demand for the services sector as well as the rest of the economy through its strong backward linkages, which suggests that in this respect a decline in manufacturing could negatively affect future growth. Services are especially important in terms of employment creation, both direct and indirect.
EXCHANGE RATES AND EMPLOYMENT
Authors: Ngandu Stewart 
Published: October 2008

AbstractThe analysis of exchange rates and employment has received scant attention in development economics. This is surprising, since there appears to be a number of well‐defined transmission channels through which exchange rates impact on employment. In South Africa this is particularly important given the rand's higher volatility relative to other emerging economies. The main focus of this paper is to give an overview of the transmission channels through which exchange rates affect employment and to discuss the standard methodological approach to conceptualising the impact of exchange rates on employment. Given the sector‐specific impact of exchange rates which are conditioned by industry characteristics, such as the degree of external orientation, there will always be winners and losers in the face of a currency shock. This means the full impact of exchange rates on employment can only be dealt with in an economy‐wide framework. Results from a computable general equilibrium (CGE) model are presented to demonstrate that even in a country with unreliable employment data such as South Africa, one can still analyse exchange rate and employment issues.
Evidence for Growth of Enterococci in Municipal Oxidation Ponds, Obtained Using Antibiotic Resistance Analysis
Authors: Moriarty Elaine , Nourozi Fariba , Robson Beth , Wood David , Gilpin Brent 
Published: October 2008

ABSTRACT
The Christchurch wastewater treatment plant uses a series of six oxidation ponds to reduce the bacterial load of treated effluent before it is discharged into the local estuary. To ensure that this discharge does not adversely affect water quality in the receiving environment, local regulations specify maximum levels in the discharge for a number of parameters, including enterococci. Between 2001 and 2006, regulations required fewer than 300 enterococci per 100 ml in summer. During this period, the discharge intermittently exceeded this limit, with unexplained levels of enterococci of up to 180,000/100 ml. Characterization of these enterococci by antibiotic resistance analysis showed that enterococci sampled over 4 months had almost identical resistance profiles. In contrast, enterococci from raw sewage and wildfowl from around the oxidation ponds had a diverse range of antibiotic resistance profiles that could be distinguished from each other and also from those of enterococci from the discharge. The hypothesis of a clonal nature of the enterococci in the discharge was supported by molecular genotype analysis, suggesting that these bacteria may have replicated in the pond environment rather than being reflective of breakthrough in the sewage treatment process or the result of recent wildfowl inputs to the ponds. This study highlights the usefulness of antibiotic resistance analysis in identifying this phenomenon and is the first report of apparent replication of a specific type of enterococci in an oxidation pond environment.
Solubilization, Activation, and Insecticidal Activity ofBacillus thuringiensisSerovar thompsoni HD542 Crystal Proteins
Authors: Naimov Samir , Boncheva Rumyana , Karlova Rumyana , Dukiandjiev Stefan , Minkov Ivan , de Maagd Ruud A. 
Published: October 2008

ABSTRACTCry15Aa protein, produced byBacillus thuringiensisserovar thompsoni HD542 in a crystal together with a 40-kDa accompanying protein, is one of a small group of nontypical, less well-studied members of the Cry family of insecticidal proteins and may provide an alternative for the more commonly used Cry proteins in insect pest management. In this paper, we describe the characterization of the Cry15Aa and 40-kDa protein's biochemical and insecticidal properties and the mode of action. Both proteins were solubilized above pH 10 in vitro. Incubation of solubilized crystal proteins with trypsin or insect midgut extracts rapidly processed the 40-kDa protein to fragments too small to be detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, whereas the Cry15 protein yielded a stable product of approximately 30 kDa. Protein N-terminal sequencing showed that Cry15 processing occurs exclusively at the C-terminal end. Cry15 protein showed in vitro hemolytic activity, which was greatly enhanced by preincubation with trypsin or insect gut extract. Larvae of the lepidopteran insectsManduca sexta,Cydia pomonella, andPieris rapaewere susceptible to crystals, and presolubilization of the crystals enhanced activity toP. rapae. Activity for all three species was enhanced by preincubation with trypsin. Larvae ofHelicoverpa armigeraandSpodoptera exiguawere relatively insensitive to crystals, and activity against these insects was not enhanced by prior solubilization or trypsin treatment. The 40-kDa crystal protein showed no activity in the insects tested, nor did its addition or coexpression inEscherichia coliincrease the activity of Cry15 in insecticidal and hemolytic assays.
Seagulls of the Berlengas Natural Reserve of Portugal as Carriers of Fecal
Escherichia coli
Harboring CTX-M and TEM Extended-Spectrum Beta-Lactamases
Authors: Poeta Patricia , Radhouani Hajer , Igrejas Gilberto , Gonçalves Alexandre , Carvalho Carlos , Rodrigues Jorge , Vinué Laura , Somalo Sergio , Torres Carmen 
Published: October 2008

ABSTRACT

Escherichia coli
isolates containing the following extended-spectrum beta-lactamases have been detected in 11 of 57 fecal samples (19.3%) in Berlengas Island seagulls: TEM-52 (eight isolates), CTX-M-1 (one isolate), CTX-M-14a (one isolate), and CTX-M-32 (one isolate). Most of the extended-spectrum beta-lactamase-positive isolates harbored class 1 or class 2 integrons, which included different antibiotic resistance gene cassettes.
Selective Removal of Aberrant Extender Units by a Type II Thioesterase for Efficient FR-008/Candicidin Biosynthesis in
Streptomyces
sp. Strain FR-008
Authors: Zhou Yongjun , Meng Qingqing , You Delin , Li Jialiang , Chen Shi , Ding Dazhong , Zhou Xiufen , Zhou Huchen , Bai Linquan , Deng Zixin 
Published: October 2008

ABSTRACT

Gene
fscTE
, encoding a putative type II thioesterase (TEII), was associated with the FR-008/candicidin gene cluster. Deletion of
fscTE
reduced approximately 90% of the FR-008/candicidin production, while the production level was well restored when
fscTE
was added back to the mutant in
trans
. FscTE was unable to compensate for the release of the maturely elongated polyketide as site-directed inactivation of the type I thioesterase (TEI) totally abolished FR-008/candicidin production. Direct biochemical analysis of FscTE in parallel with its homologue TylO from the tylosin biosynthetic pathway demonstrated their remarkable preferences for acyl-thioesters (i.e., propionyl-
S
-
N
-acetylcysteamine [SNAC] over methylmalonyl-SNAC and acetyl-SNAC over malonyl-SNAC) and thus concluded that TEII could maintain effective polyketide biosynthesis by selectively removing the nonelongatable residues bound to acyl carrier proteins. Overexpression of FscTE under the strong constitutive
ermE
*
p
promoter in the wild-type strain did not suppress FR-008/candicidin formation, which confirmed its substrate specificity in vivo. Furthermore, successful complementation of the
fscTE
mutant was obtained with
fscTE
and
tylO
, whereas no complementation was detected with nonribosomal peptide synthetase (NRPS) TEII
tycF
and
srfAD
, reflecting substrate specificities of TEIIs distinctive from those of either polyketide synthases or NRPSs.
Substrate-Specific Clades of Active Marine Methylotrophs Associated with a Phytoplankton Bloom in a Temperate Coastal Environment
Authors: Neufeld Josh D. , Boden Rich , Moussard Hélène , Schäfer Hendrik , Murrell J. Colin 
Published: October 2008

ABSTRACT

Marine microorganisms that consume one-carbon (C
1
) compounds are poorly described, despite their impact on global climate via an influence on aquatic and atmospheric chemistry. This study investigated marine bacterial communities involved in the metabolism of C
1
compounds. These communities were of relevance to surface seawater and atmospheric chemistry in the context of a bloom that was dominated by phytoplankton known to produce dimethylsulfoniopropionate. In addition to using 16S rRNA gene fingerprinting and clone libraries to characterize samples taken from a bloom transect in July 2006, seawater samples from the phytoplankton bloom were incubated with
13
C-labeled methanol, monomethylamine, dimethylamine, methyl bromide, and dimethyl sulfide to identify microbial populations involved in the turnover of C
1
compounds, using DNA stable isotope probing. The [
13
C]DNA samples from a single time point were characterized and compared using denaturing gradient gel electrophoresis (DGGE), fingerprint cluster analysis, and 16S rRNA gene clone library analysis. Bacterial community DGGE fingerprints from
13
C-labeled DNA were distinct from those obtained with the DNA of the nonlabeled community DNA and suggested some overlap in substrate utilization between active methylotroph populations growing on different C
1
substrates. Active methylotrophs were affiliated with
Methylophaga
spp. and several clades of undescribed
Gammaproteobacteria
that utilized methanol, methylamines (both monomethylamine and dimethylamine), and dimethyl sulfide. rRNA gene sequences corresponding to populations assimilating
13
C-labeled methyl bromide and other substrates were associated with members of the
Alphaproteobacteria
(e.g., the family
Rhodobacteraceae
), the
Cytophaga-Flexibacter-Bacteroides
group, and unknown taxa. This study expands the known diversity of marine methylotrophs in surface seawater and provides a comprehensive data set for focused cultivation and metagenomic analyses in the future.
Long-Term Fungal Inhibitory Activity of Water-Soluble Extracts of
Phaseolus vulgaris
cv. Pinto and Sourdough Lactic Acid Bacteria during Bread Storage
Authors: Coda Rossana , Rizzello Carlo G. , Nigro Franco , De Angelis Maria , Arnault Philip , Gobbetti Marco 
Published: October 2008

ABSTRACT

The antifungal activity of proteinaceous compounds from different food matrices was investigated. In initial experiments, water-soluble extracts of wheat sourdoughs, cheeses, and vegetables were screened by agar diffusion assays with
Penicillium roqueforti
DPPMAF1 as the indicator fungus. Water-soluble extracts of sourdough fermented with
Lactobacillus brevis
AM7 and
Phaseolus vulgaris
cv. Pinto were selected for further study. The crude water-soluble extracts of
L. brevis
AM7 sourdough and
P. vulgaris
cv. Pinto had a MIC of 40 mg of peptide/ml and 30.9 mg of protein/ml, respectively. MICs were markedly lower when chemically synthesized peptides or partially purified protein fractions were used. The water-soluble extract of
P. vulgaris
cv. Pinto showed inhibition toward a large number of fungal species isolated from bakeries. Phaseolin alpha-type precursor, phaseolin, and erythroagglutinating phytohemagglutinin precursor were identified in the water-soluble extract of
P. vulgaris
cv. Pinto by nano liquid chromatography-electrospray ionization-tandem mass spectrometry. When the antifungal activity was assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, all three proteins were inhibitory. A mixture of eight peptides was identified from the water-soluble extract of sourdough
L. brevis
AM7, and five of these exhibited inhibitory activity. Bread was made at the pilot plant scale by sourdough fermentation with
L. brevis
AM7 and addition of the water-soluble extract (27%, vol/wt; 5 mg of protein/ml) of
P. vulgaris
cv. Pinto. Slices of bread packed in polyethylene bags did not show contamination by fungi until at least 21 days of storage at room temperature, a level of protection comparable to that afforded by 0.3% (wt/wt) calcium propionate.
The Functional Quality of Soluble Recombinant Polypeptides Produced in
Escherichia coli
Is Defined by a Wide Conformational Spectrum
Authors: Martínez-Alonso Mónica , González-Montalbán Nuria , García-Fruitós Elena , Villaverde Antonio 
Published: October 2008

ABSTRACT

We have observed that a soluble recombinant green fluorescent protein produced in
Escherichia coli
occurs in a wide conformational spectrum. This results in differently fluorescent protein fractions in which morphologically diverse soluble aggregates abound. Therefore, the functional quality of soluble versions of aggregation-prone recombinant proteins is defined statistically rather than by the prevalence of a canonical native structure.
Brucella abortus
Strain RB51 Leucine Auxotroph as an Environmentally Safe Vaccine for Plasmid Maintenance and Antigen Overexpression
Authors: Rajasekaran Parthiban , Seleem Mohamed N. , Contreras Andrea , Purwantini Endang , Schurig Gerhardt G. , Sriranganathan Nammalwar , Boyle Stephen M. 
Published: October 2008

ABSTRACT

To avoid potentiating the spread of an antibiotic resistance marker, a plasmid expressing a
leuB
gene and a heterologous antigen, green fluorescent protein (GFP), was shown to complement a leucine auxotroph of cattle vaccine strain
Brucella abortus
RB51, which protected CD1 mice from virulent
B. abortus
2308 and elicited GFP antibodies.
Isolation of
Rhodococcus
sp. Strain ECU0066, a New Sulfide Monooxygenase-Producing Strain for Asymmetric Sulfoxidation
Authors: Li Ai-Tao , Zhang Jian-Dong , Xu Jian-He , Lu Wen-Ya , Lin Guo-Qiang 
Published: October 2008

ABSTRACT

A new and efficient sulfide monooxygenase-producing strain, ECU0066, was isolated and identified as a
Rhodococcus
sp. that could transform phenylmethyl sulfide (PMS) to (
S
)-sulfoxide with 99% enantiomeric excess via two steps of enantioselective oxidations. Its enzyme activity could be effectively induced by adding PMS or phenylmethyl sulfoxide (PMSO) directly to a rich medium at the early log phase (6 h) of fermentation, resulting in over 10-times-higher production of the enzyme. This bacterial strain also displayed fairly good activity and enantioselectivity toward seven other sulfides, indicating a good potential for practical application in asymmetric synthesis of chiral sulfoxides.
Influence of Soil Components on the Biodegradation of Benzene, Toluene, Ethylbenzene, and
o-
,
m-
, and
p
-Xylenes by the Newly Isolated Bacterium
Pseudoxanthomonas spadix
BD-a59
Authors: Kim Jeong Myeong , Le Ngoc Thuan , Chung Bok Sil , Park Jin Ho , Bae Jin-Woo , Madsen Eugene L. , Jeon Che Ok 
Published: October 2008

ABSTRACT

A bacterium designated strain BD-a59, able to degrade all six benzene, toluene, ethylbenzene, and
o-
,
m-
, and
p
-xylene (BTEX) compounds, was isolated by plating gasoline-contaminated sediment from a gasoline station in Geoje, Republic of Korea, without enrichment, on minimal salts basal (MSB) agar containing 0.01% yeast extract, with BTEX as the sole carbon and energy source. Taxonomic analyses showed that the isolate belonged to
Pseudoxanthomonas spadix
, and until now, the genus
Pseudoxanthomonas
has not included any known BTEX degraders. The BTEX biodegradation rate was very low in MSB broth, but adding a small amount of yeast extract greatly enhanced the biodegradation. Interestingly, degradation occurred very quickly in slurry systems amended with sterile soil solids but not with aqueous soil extract. Moreover, if soil was combusted first to remove organic matter, the enhancement effect on BTEX biodegradation was lost, indicating that some components of insoluble organic compounds are nutritionally beneficial for BTEX degradation. Reverse transcriptase PCR-based analysis of field-fixed mRNA revealed expression of the
tmoA
gene, whose sequence was closely related to that carried by strain BD-a59. This study suggests that strain BD-a59 has the potential to assist in BTEX biodegradation at contaminated sites.
Knockout of the Erythromycin Biosynthetic Cluster Gene,
eryBI
, Blocks Isoflavone Glucoside Bioconversion during Erythromycin Fermentations in
Aeromicrobium erythreum
but Not in
Saccharopolyspora erythraea
Authors: Reeves Andrew R. , Seshadri Ramya , Brikun Igor A. , Cernota William H. , Gonzalez Melissa C. , Weber J. Mark 
Published: October 2008

ABSTRACT

Isoflavone glucosides are valuable nutraceutical compounds and are present in commercial fermentations, such as the erythromycin fermentation, as constituents of the soy flour in the growth medium. The purpose of this study was to develop a method for recovery of the isoflavone glucosides as value-added coproducts at the end of either
Saccharopolyspora erythraea
or
Aeromicrobium erythreum
fermentation. Because the first step in isoflavone metabolism was known to be the conversion of isoflavone glucosides to aglycones by a β-glucosidase, we chose to knock out the only β-glucosidase gene known at the start of the study,
eryBI
, to see what effect this had on metabolism of isoflavone glucosides in each organism. In the unicellular erythromycin producer
A. erythreum
, knockout of
eryBI
was sufficient to block the conversion of isoflavone glucosides to aglycones. In
S. erythraea
, knockout of
eryBI
had no effect on this reaction, suggesting that other β-glucosidases are present. Erythromycin production was not significantly affected in either strain as a result of the
eryBI
knockout. This study showed that isoflavone metabolism could be blocked in
A. erythreum
by
eryBI
knockout but that
eryBI
knockout was not sufficient to block isoflavone metabolism in
S. erythraea
.
TFIIIC Binding Sites Function as both Heterochromatin Barriers and Chromatin Insulators in
Saccharomyces cerevisiae
Authors: Simms Tiffany A. , Dugas Sandra L. , Gremillion Jason C. , Ibos Megan E. , Dandurand M. Nicole , Toliver Tasha T. , Edwards Daniel J. , Donze David 
Published: October 2008

ABSTRACT

Chromosomal sites of RNA polymerase III (Pol III) transcription have been demonstrated to have “extratranscriptional” functions, as the assembled Pol III complex can act as chromatin boundaries or pause sites for replication forks, can alter nucleosome positioning or affect transcription of neighboring genes, and can play a role in sister chromatid cohesion. Several studies have demonstrated that assembled Pol III complexes block the propagation of heterochromatin-mediated gene repression. Here we show that in
Saccharomyces cerevisiae
tRNA genes (tDNAs) and even partially assembled Pol III complexes containing only the transcription factor TFIIIC can exhibit chromatin boundary functions both as heterochromatin barriers and as insulators to gene activation. Both the
TRT2
tDNA and the
ETC4
site which binds only the TFIIIC complex prevented an upstream activation sequence from activating the
GAL
promoters in our assay system, effectively acting as chromatin insulators. Additionally, when placed downstream from the heterochromatic
HMR
locus,
ETC4
blocked the ectopic spread of Sir protein-mediated silencing, thus functioning as a barrier to repression. Finally, we show that
TRT2
and the
ETC6
site upstream of
TFC6
in their natural contexts display potential insulator-like functions, and
ETC6
may represent a novel case of a Pol III factor directly regulating a Pol II promoter. The results are discussed in the context of how the TFIIIC transcription factor complex may function to demarcate chromosomal domains in yeast and possibly in other eukaryotes.
H3K9 Methylation Regulates Growth and Development in
Aspergillus fumigatus
Authors: Palmer Jonathan M. , Perrin Robyn M. , Dagenais Taylor R. T. , Keller Nancy P. 
Published: October 2008

ABSTRACT

In most species, chromatin remodeling mediates critical biological processes ranging from development to disease states. In fungi within the genus
Aspergillus
, chromatin remodeling may regulate expression of metabolic gene clusters, but other processes regulated by chromatin structure remain to be elucidated. In many eukaryotic species, methylation of lysine 9 of histone 3 (H3K9) is a hallmark of heterochromatin formation and subsequent gene silencing. The sole H3K9 methyltransferase in
Schizosaccharomyces pombe
is Clr4. We report that disruption of the Clr4 homolog in the pathogenic mold
Aspergillus fumigatus
(ClrD), which is involved in both mono- and trimethylation of H3K9, results in several growth abnormalities. Developmental defects in ΔAf
clrD
include reduction in radial growth, reduction in conidial production, and delayed conidiation after developmental competence mediated by delayed expression of
brlA
, the master regulator of conidiophore development. Sensitivity of ΔAf
clrD
to 6-azauracil suggests that ClrD influences transcriptional processing in
A. fumigatus
. Despite growth abnormalities, macrophage assays suggest ClrD may be dispensable for host interactions.