bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of the Thermostability Properties of Three Acid Phosphatases from Molds:
Aspergillus fumigatus
Phytase,
A. niger
Phytase, and
A. niger
pH 2.5 Acid Phosphatase
Authors: Wyss Markus , Pasamontes Luis , Rémy Roland , Kohler Josiane , Kusznir Eric , Gadient Martin , Müller Francis , van Loon Adolphus P. G. M. 
Published: December 2019

ABSTRACT

Enzymes that are used as animal feed supplements should be able to withstand temperatures of 60 to 90°C, which may be reached during the feed pelleting process. The thermostability properties of three histidine acid phosphatases,
Aspergillus fumigatus
phytase,
Aspergillus niger
phytase, and
A. niger
optimum pH 2.5 acid phosphatase, were investigated by measuring circular dichroism, fluorescence, and enzymatic activity. The phytases of
A. fumigatus
and
A. niger
were both denatured at temperatures between 50 and 70°C. After heat denaturation at temperatures up to 90°C,
A. fumigatus
phytase refolded completely into a nativelike, fully active conformation, while in the case of
A. niger
phytase exposure to 55 to 90°C was associated with an irreversible conformational change and with losses in enzymatic activity of 70 to 80%. In contrast to these two phytases,
A. niger
pH 2.5 acid phosphatase displayed considerably higher thermostability; denaturation, conformational changes, and irreversible inactivation were observed only at temperatures of ≥80°C. In feed pelleting experiments performed at 75°C, the recoveries of the enzymatic activities of the three acid phosphatases were similar (63 to 73%). At 85°C, however, the recovery of enzymatic activity was considerably higher for
A. fumigatus
phytase (51%) than for
A. niger
phytase (31%) or pH 2.5 acid phosphatase (14%). These findings confirm that
A. niger
pH 2.5 acid phosphatase is irreversibly inactivated at temperatures above 80°C and that the capacity of
A. fumigatus
phytase to refold properly after heat denaturation may favorably affect its pelleting stability.
Degradation of Phthalate and Di-(2-Ethylhexyl)phthalate by Indigenous and Inoculated Microorganisms in Sludge-Amended Soil
Authors: Roslev Peter , Madsen Peter L. , Thyme Jesper B. , Henriksen Kaj 
Published: December 2019

ABSTRACT

The metabolism of phthalic acid (PA) and di-(2-ethylhexyl)phthalate (DEHP) in sludge-amended agricultural soil was studied with radiotracer techniques. The initial rates of metabolism of PA and DEHP (4.1 nmol/g [dry weight]) were estimated to be 731.8 and 25.6 pmol/g (dry weight) per day, respectively. Indigenous microorganisms assimilated 28 and 17% of the carbon in [
14
C]PA and [
14
C]DEHP, respectively, into microbial biomass. The rates of DEHP metabolism were much greater in sludge assays without soil than in assays with sludge-amended soil. Mineralization of [
14
C]DEHP to
14
CO
2
increased fourfold after inoculation of sludge and soil samples with DEHP-degrading strain SDE 2. The elevated mineralization potential was maintained for more than 27 days. Experiments performed with strain SDE 2 suggested that the bioavailability and mineralization of DEHP decreased substantially in the presence of soil and sludge components. The microorganisms metabolizing PA and DEHP in sludge and sludge-amended soil were characterized by substrate-specific radiolabelling, followed by analysis of
14
C-labelled phospholipid ester-linked fatty acids (
14
C-PLFAs). This assay provided a radioactive fingerprint of the organisms actively metabolizing [
14
C]PA and [
14
C]DEHP. The
14
C-PLFA fingerprints showed that organisms with different PLFA compositions metabolized PA and DEHP in sludge-amended soil. In contrast, microorganisms with comparable
14
C-PLFA fingerprints were found to dominate DEHP metabolism in sludge and sludge-amended soil. Our results suggested that indigenous sludge microorganisms dominated DEHP degradation in sludge-amended soil. Mineralization of DEHP and PA followed complex kinetics that could not be described by simple first-order equations. The initial mineralization activity was described by an exponential function; this was followed by a second phase that was described best by a fractional power function. In the initial phase, the half times for PA and DEHP in sludge-amended soil were 2 and 58 days, respectively. In the late phase of incubation, the apparent half times for PA and DEHP increased to 15 and 147 days, respectively. In the second phase (after more than 28 days), the half time for DEHP was 2.9 times longer in sludge-amended soil assays than in sludge assays without soil. Experiments with radiolabelled DEHP degraders suggested that a significant fraction of the
14
CO
2
produced in long-term degradation assays may have originated from turnover of labelled microbial biomass rather than mineralization of [
14
C]PA or [
14
C]DEHP. It was estimated that a significant amount of DEHP with poor biodegradability and extractability remains in sludge-amended soil for extended periods of time despite the presence of microorganisms capable of degrading the compound (e.g., more than 40% of the DEHP added is not mineralized after 1 year).
Purification, Characterization, and Molecular Analysis of Thermostable Cellulases CelA and CelB from
Thermotoga neapolitana
Authors: Bok Jin-Duck , Yernool Dinesh A. , Eveleigh Douglas E. 
Published: December 2019

ABSTRACT

Two thermostable endocellulases, CelA and CelB, were purified from
Thermotoga neapolitana
. CelA (molecular mass, 29 kDa; pI 4.6) is optimally active at pH 6.0 at 95°C, while CelB (molecular mass, 30 kDa; pI 4.1) has a broader optimal pH range (pH 6.0 to 6.6) at 106°C. Both enzymes are characterized by a high level of activity (high
V
max
value and low apparent

K
m

value) with carboxymethyl cellulose; the specific activities of CelA and CelB are 1,219 and 1,536 U/mg, respectively. With
p
-nitrophenyl cellobioside the
V
max
values of CelA and CelB are 69.2 and 18.4 U/mg, respectively, while the

K
m

values are 0.97 and 0.3 mM, respectively. The major end products of cellulose hydrolysis, glucose and cellobiose, competitively inhibit CelA, and CelB. The

K
i

values for CelA are 0.44 M for glucose and 2.5 mM for cellobiose; the

K
i

values for CelB are 0.2 M for glucose and 1.16 mM for cellobiose. CelB preferentially cleaves larger cellooligomers, producing cellobiose as the end product; it also exhibits significant transglycosylation activity. This enzyme is highly thermostable and has half-lives of 130 min at 106°C and 26 min at 110°C. A single clone encoding the
celA
and
celB
genes was identified by screening a
T. neapolitana
genomic library in
Escherichia coli
. The
celA
gene encodes a 257-amino-acid protein, while
celB
encodes a 274-amino-acid protein. Both proteins belong to family 12 of the glycosyl hydrolases, and the two proteins are 60% similar to each other. Northern blots of
T. neapolitana
mRNA revealed that
celA
and
celB
are monocistronic messages, and both genes are inducible by cellobiose and are repressed by glucose.
Isolation, Purification, and Characterization of the PR Oxidase from
Penicillium roqueforti
Authors: Chang Shenq-Chyi , Lei Wen-Yee , Tsai Ying-Chieh , Wei Yau-Huei 
Published: December 2019

ABSTRACT

The PR oxidase, an extracellular enzyme, involved in the conversion of PR toxin into PR acid, was purified from the culture broth of
Penicillium roqueforti
ATCC 48936. The enzyme has a pI of 4.5 and a molecular mass of approximately 88 kDa, and it is a monomer. The optimum pH for this enzyme is ca. 4.0, and the optimum temperature is 50°C.
Detection of
Mycoplasma hyopneumoniae
by Air Sampling with a Nested PCR Assay
Authors: Stärk Katharina D. C. , Nicolet Jacques , Frey Joachim 
Published: December 2019

ABSTRACT

This article describes the first successful detection of airborne
Mycoplasma hyopneumoniae
under experimental and field conditions with a new nested PCR assay. Air was sampled with polyethersulfone membranes (pore size, 0.2 μm) mounted in filter holders. Filters were processed by dissolution and direct extraction of DNA for PCR analysis. For the PCR, two nested pairs of oligonucleotide primers were designed by using an
M. hyopneumoniae
-specific DNA sequence of a repeated gene segment. A nested PCR assay was developed and used to analyze samples collected in eight pig houses where respiratory problems had been common. Air was also sampled from a mycoplasma-free herd. The nested PCR was highly specific and 10
4
times as sensitive as a one-step PCR. Under field conditions, the sampling system was able to detect airborne
M. hyopneumoniae
on 80% of farms where acute respiratory disease was present. No airborne
M. hyopneumoniae
was detected on infected farms without acute cases. The chance of successful detection was increased if air was sampled at several locations within a room and at a lower air humidity.
Photometric Application of the Gram Stain Method To Characterize Natural Bacterial Populations in Aquatic Environments
Authors: Saida H. , Ytow N. , Seki H. 
Published: December 2019

ABSTRACTThe Gram stain method was applied to the photometric characterization of aquatic bacterial populations with a charge-coupled device camera and an image analyzer.Escherichia coliandBacillus subtiliswere used as standards of typical gram-negative and gram-positive bacteria, respectively. A mounting agent to obtain clear images of Gram-stained bacteria on Nuclepore membrane filters was developed. The bacterial stainability by the Gram stain was indicated by the Gram stain index (GSI), which was applicable not only to the dichotomous classification of bacteria but also to the characterization of cell wall structure. The GSI spectra of natural bacterial populations in water with various levels of eutrophication showed a distinct profile, suggesting possible staining specificity that indicates the presence of a particular bacterial population in the aquatic environment.
Characterization of the Cricket Hindgut Microbiota with Fluorescently Labeled rRNA-Targeted Oligonucleotide Probes
Authors: Santo Domingo Jorge W. , Kaufman Michael G. , Klug Michael J. , Tiedje James M. 
Published: December 2019

ABSTRACT

Most cricket hindgut microorganisms (60 to 80%) were detected with a universal fluorescent rRNA-targeted probe and found to be eubacteria. Group-specific probes showed that the hindguts of five different cricket species harbor similar bacterial groups, although in different proportions, and that different diets shifted the structure of the hindgut microbial community. The
Bacteroides-Prevotella
probe, of the eight eubacterial probes tested, stained the largest percentage of cells in all crickets.
Detection of mRNA by Reverse Transcription-PCR as an Indicator of Viability in
Escherichia coli
Cells
Authors: Sheridan G. E. C. , Masters C. I. , Shallcross J. A. , Mackey B. M. 
Published: December 2019

ABSTRACT

The relationship between the detection of mRNA and cellular viability in
Escherichia coli
was investigated in cells killed by heat or ethanol. Reverse transcription-PCR (RT-PCR) methods were developed for detecting mRNA from
rpoH
,
groEL
, and
tufA
genes. mRNA from all three genes was detected immediately after the cells had been killed by heat or ethanol but gradually disappeared with time when dead cells were held at room temperature. In heat-killed cells, some mRNA targets became undetectable after 2 to 16 h, whereas after ethanol treatment, mRNA was still detected after 16 h. In contrast, 16S rRNA was detected by RT-PCR in all samples containing dead cells and did not disappear during a subsequent incubation of 16 h at room temperature. Of the different types of nucleic acid, mRNA is the most promising candidate for an indicator of viability in bacteria, but its persistence in dead cells depends on the inactivating treatment and subsequent holding conditions.
Effect of Temperature on Adhesion of
Vibrio
Strain AK-1 to
Oculina patagonica
and on Coral Bleaching
Authors: Toren A. , Landau L. , Kushmaro A. , Loya Y. , Rosenberg E. 
Published: December 2019

ABSTRACT

Laboratory aquarium experiments demonstrated that
Vibrio
strain AK-1 caused rapid and extensive bleaching of the coral
Oculina patagonica
at 29°C, slower and less-complete bleaching at 23°C, and no bleaching at 16°C. At 29°C, the application of approximately 100
Vibrio
strain AK-1 cells directly onto the coral caused 50 and 83% bleaching after 10 and 20 days, respectively. At 16°C, there was no bleaching, even with an initial inoculum of 1.2 × 10
8
bacteria. To begin to understand the effect of seawater temperature on bleaching of
O. patagonica
by
Vibrio
strain AK-1, adhesion of the bacteria to the coral as a function of temperature was studied. Inoculation of 10
7
Vibrio
strain AK-1 organisms into flasks containing 20 ml of seawater at 25°C and a fragment of
O. patagonica
resulted in net levels of bacterial adhesion to the coral of 45, 78, and 84% after 2, 6, and 8 h, respectively. The adhesion was inhibited 65% by 0.001%
d
-galactose and 94% by 0.001% methyl-β-
d
-galactopyranoside (β-M-Gal). After the incubation of
Vibrio
strain AK-1 with the coral for 6 h, 42% of the input bacteria were released from the coral with 0.01% β-M-Gal, compared to less than 0.2% when β-M-Gal was present during the adhesion step. Adhesion did not occur when
Vibrio
strain AK-1 was grown at 16°C, regardless of whether the corals were maintained at 16 or 25°C, whereas bacteria grown at 25°C adhered to corals maintained at 16 or 25°C. Bacteria grown at 25°C adhered avidly to Sepharose beads containing covalently bound β-
d
-galactopyranoside but failed to bind if grown at 16°C. These data suggest that elevated seawater temperatures may cause coral bleaching by allowing for the expression of adhesin genes of
Vibrio
strain AK-1.
Transformation of
Acinetobacter
sp. Strain BD413 by Transgenic Sugar Beet DNA
Authors: Gebhard Frank , Smalla Kornelia 
Published: December 2019

ABSTRACT

The ability of
Acinetobacter
sp. strain BD413(pFG4Δ
npt
II) to take up and integrate transgenic plant DNA based on homologous recombination was studied under optimized laboratory conditions. Restoration of
npt
II, resulting in kanamycin-resistant transformants, was observed with plasmid DNA, plant DNA, and homogenates carrying the gene
npt
II. Molecular analysis showed that some transformants not only restored the 317-bp deletion but also obtained additional DNA.
Biodegradation of Aliphatic-Aromatic Copolyesters by
Thermomonospora fusca
and Other Thermophilic Compost Isolates
Authors: Kleeberg Ilona , Hetz Claudia , Kroppenstedt Reiner Michael , Müller Rolf-Joachim , Deckwer Wolf-Dieter 
Published: December 2019

ABSTRACT

Random aliphatic-aromatic copolyesters synthesized from 1,4-butanediol, adipic acid, and terephthalic acid (BTA) have excellent thermal and mechanical properties and are biodegradable by mixed cultures (e.g., in compost). Over 20 BTA-degrading strains were isolated by using compost as a microbial source. Among these microorganisms, thermophilic actinomycetes obviously play an outstanding role and appear to dominate the initial degradation step. Two actinomycete strains exhibited about 20-fold higher BTA degradation rates than usually observed in a common compost test. These isolates were identified as
Thermomonospora fusca
strains. They appeared to be particularly suitable for establishment of rapid degradation tests and were used in comparative studies on the biodegradation of various polyesters.
Transcriptional Activation of the
Aspergillus nidulans gpdA
Promoter by Osmotic Signals
Authors: Redkar Rajendra J. , Herzog Roland W. , Singh Narendra K. 
Published: December 2019

ABSTRACT

A differentially expressed
gpdA
cDNA clone was isolated from NaCl-adapted
Aspergillus nidulans
(FGSC359) and identified as glyceraldehyde-3-phosphate dehydrogenase (
gpdA
) on the basis of its nucleotide sequence. The level of
gpdA
RNA substantially increased in cultures gradually adapted to NaCl but was greatly reduced in cultures exposed briefly to a high concentration of NaCl. A
pyrG
auxotroph of
A. nidulans
(A773) was cotransformed with a
gpdA-uidA
construct and a plasmid containing the
Neurospora crassa pyr4
gene as a selectable marker. One
pyrG
+
β-glucuronidase-positive (GUS
+
) transformant was selected, and stable integration of the
gpdA-uidA
construct into the genome was confirmed by Southern blot analysis. Gradual adaptation to increasing concentrations of NaCl resulted in an increase in GUS activity to 2.7-fold. GUS activity was reduced after a 2-h exposure of an unadapted culture to 2 M NaCl but gradually increased to a maximum of twofold after 24 h. GUS activity also increased by 8.4-fold in Na
2
SO
4
-adapted cultures, 4.9-fold in polyethylene glycol-adapted cultures, and 7.5-fold in KCl-adapted cultures. These results are consistent with the hypothesis that the
A. nidulans gpdA
promoter is transcriptionally activated by osmotic signals.
Growth of
Geobacter sulfurreducens
with Acetate in Syntrophic Cooperation with Hydrogen-Oxidizing Anaerobic Partners
Authors: Cord-Ruwisch Ralf , Lovley Derek R. , Schink Bernhard 
Published: December 2019

ABSTRACT

Pure cultures of
Geobacter sulfurreducens
and other Fe(III)-reducing bacteria accumulated hydrogen to partial pressures of 5 to 70 Pa with acetate, butyrate, benzoate, ethanol, lactate, or glucose as the electron donor if electron release to an acceptor was limiting.
G. sulfurreducens
coupled acetate oxidation with electron transfer to an anaerobic partner bacterium in the absence of ferric iron or other electron acceptors. Cocultures of
G. sulfurreducens
and
Wolinella succinogenes
with nitrate as the electron acceptor degraded acetate efficiently and grew with doubling times of 6 to 8 h. The hydrogen partial pressures in these acetate-degrading cocultures were considerably lower, in the range of 0.02 to 0.04 Pa. From these values and the concentrations of the other reactants, it was calculated that in this cooperation the free energy change available to
G. sulfurreducens
should be about −53 kJ per mol of acetate oxidized, assuming complete conversion of acetate to CO
2
and H
2
. However, growth yields (18.5 g of dry mass per mol of acetate for the coculture, about 14 g for
G. sulfurreducens
) indicated considerably higher energy gains. These yield data, measurement of hydrogen production rates, and calculation of the diffusive hydrogen flux indicated that electron transfer in these cocultures may not proceed exclusively via interspecies hydrogen transfer but may also proceed through an alternative carrier system with higher redox potential, e.g., a
c
-type cytochrome that was found to be excreted by
G. sulfurreducens
into the culture fluid. Syntrophic acetate degradation was also possible with
G. sulfurreducens
and
Desulfovibrio desulfuricans
CSN but only with nitrate as electron acceptor. These cultures produced cell yields of 4.5 g of dry mass per mol of acetate, to which both partners contributed at about equal rates. These results demonstrate that some Fe(III)-reducing bacteria can oxidize organic compounds under Fe(III) limitation with the production of hydrogen, and they provide the first example of rapid acetate oxidation via interspecies electron transfer at moderate temperature.
Mycobacterium aviumBacilli Grow Saprozoically in Coculture withAcanthamoeba polyphagaand Survive within Cyst Walls
Authors: Steinert Michael , Birkness Kristin , White Elizabeth , Fields Barry , Quinn Frederick 
Published: December 2019

ABSTRACTProtozoans are gaining recognition as environmental hosts for a variety of waterborne pathogens. We compared the growth ofMycobacterium avium, a human pathogen associated with domestic water supplies, in coculture with the free-living amoebaAcanthamoeba polyphagawith the growth ofM. aviumwhen it was separated from amoebae by a 0.1-μm-pore-size polycarbonate membrane (in a parachamber). Although viable mycobacteria were observed within amoebal vacuoles, there was no significant difference between bacterial growth in coculture and bacterial growth in the parachamber. This suggests thatM. aviumis able to grow saprozoically on products secreted by the amoebae. In contrast,Legionella pneumophila, a well-studied intracellular parasite of amoebae, multiplied only in coculture. A comparison of amoebae infected withL. pneumophilaand amoebae infected withM. aviumby electron microscopy demonstrated that there were striking differences in the locations of the bacteria within amoebal cysts. WhileL. pneumophilaresided within the cysts,M. aviumwas found within the outer walls of the double-walled cysts ofA. polyphaga. These locations may provide a reservoir for the bacteria when environmental conditions become unfavorable.
Comparison of Membrane Filtration and Multiple-Tube Fermentation by the Colilert and Enterolert Methods for Detection of Waterborne Coliform Bacteria,
Escherichia coli
, and Enterococci Used in Drinking and Bathing Water Quality Monitoring in Southern Sweden
Authors: Eckner Karl F. 
Published: December 2019

ABSTRACT

A total of 338 water samples, 261 drinking water samples and 77 bathing water samples, obtained for routine testing were analyzed in duplicate by Swedish standard methods using multiple-tube fermentation or membrane filtration and by the Colilert and/or Enterolert methods. Water samples came from a wide variety of sources in southern Sweden (Skåne). The Colilert method was found to be more sensitive than Swedish standard methods for detecting coliform bacteria and of equal sensitivity for detecting
Escherichia coli
when all drinking water samples were grouped together. Based on these results, Swedac, the Swedish laboratory accreditation body, approved for the first time in Sweden use of the Colilert method at this laboratory for the analysis of all water sources not falling under public water regulations (A-krav). The coliform detection study of bathing water yielded anomalous results due to confirmation difficulties.
E. coli
detection in bathing water was similar by both the Colilert and Swedish standard methods as was fecal streptococcus and enterococcus detection by both the Enterolert and Swedish standard methods.
Beauvericin Production by
Fusarium
Species
Authors: Logrieco A. , Moretti A. , Castella G. , Kostecki M. , Golinski P. , Ritieni A. , Chelkowski J. 
Published: December 2019

ABSTRACT

Beauvericin is a cyclohexadepsipeptide mycotoxin which has insecticidal properties and which can induce apoptosis in mammalian cells. Beauvericin is produced by some entomo- and phytopathogenic
Fusarium
species (
Fusarium proliferatum
,
F. semitectum
, and
F. subglutinans
) and occurs naturally on corn and corn-based foods and feeds infected by
Fusarium
spp. We tested 94
Fusarium
isolates belonging to 25 taxa, 21 in 6 of the 12 sections of the
Fusarium
genus and 4 that have been described recently, for the ability to produce beauvericin. Beauvericin was produced by the following species (with the number of toxigenic strains compared with the number of tested strains given in parentheses):
Fusarium acuminatum
var.
acuminatum
(1 of 4),
Fusarium acuminatum
var.
armeniacum
(1 of 3),
F. anthophilum
(1 of 2),
F. avenaceum
(1 of 6),
F. beomiforme
(1 of 1),
F. dlamini
(2 of 2),
F. equiseti
(2 of 3),
F. longipes
(1 of 2),
F. nygamai
(2 of 2),
F. oxysporum
(4 of 7),
F. poae
(4 of 4),
F. sambucinum
(12 of 14), and
F. subglutinans
(3 of 3). These results indicate that beauvericin is produced by many species in the genus
Fusarium
and that it may be a contaminant of cereals other than maize.