bluuebunny/crossref_metadata_2025_split huggingface dataset:
ANTIOXIDANT ACTIVITY OF EXTRACTS OF MALLOTUS PHILIPPINENSIS FRUIT AND BARK
Authors: ARFAN MOHAMMAD , AMIN HAZRAT , KARAMAĆ MAGDALENA , KOSIŃSKA AGNIESZKA , SHAHIDI FEREIDOON , WICZKOWSKI WIESŁAW , AMAROWICZ RYSZARD 
Published: August 2007

ABSTRACT Several extracts from Mallotus philippinensis fruits and bark were prepared and evaluated for their total antioxidant activity (TAA), antiradical activity against DPPH· (2,2‐diphenyl‐1‐picrylhydrazyl radical) and reducing power. The total phenolics and tannin contents in extracts were determined. The extract of the bark showed the strongest antiradical activity and reduction power; its TAA was 5.27 mmol Trolox equivalents/g. The TAA of other extracts ranged from 0.05 to 1.79 mmol Trolox equivalents/g extract. The content of total phenolics in the bark extract was 541 mg/g. The content of tannins in MP‐4, expressed as absorbance units per mg at 500 nm, was found to be 0.412. Several phenolic constituents in the extracts were detected by reverse‐phase high‐performance liquid chromatography using a gradient solvent system with UV‐DAD detection. Acetone was a suitable solvent for extraction of natural antioxidants from M. philippinensis fruits.PRACTICAL APPLICATIONSAn acetonic and methanolic extraction of Mallotus philippinensis fruit and bark affords extracts that have been characterized as possessing strong antioxidant activities; this may open new avenues for the utilization of these extract as nutraceuticals. The biological activity of compounds present in the extracts has been well documented in many studies published in scientific journals. We want to emphasize that a procyanidin‐rich extract from pine (Pinus maritime) bark was patented under the trade name of Pycnogenol (PYC) and is utilized throughout the world as a nutritional supplement and as a phytochemical remedy for various diseases ranging from chronic inflammation to circulatory dysfunction (Packer et al. 1999).
PEANUT SKIN ANTIOXIDANTS
Authors: VAN HA HOANG , POKORNÝ JAN , SAKURAI HIDETOSHI 
Published: August 2007

ABSTRACT Peanut skins isolated from three peanut samples cultivated in China were extracted with hexane, ethyl acetate and methanol. The content of polyphenolic substances was low in hexane extracts, very high in methanolic extracts and intermediate in ethyl acetate extracts. Condensed tannins prevailed in ethyl acetate and methanol extracts, while tocopherols were concentrated in hexane extracts, but only in moderate amounts. The resveratrol content was very low. The antioxidant activity of extracts was rather low in lard and in vegetable oils under conditions of the Schaal oven test, but the free radical‐scavenging activity was very pronounced, especially in methanol extracts. The metal‐chelating activity could contribute to the antioxidant activity of peanut skin extracts. PRACTICAL APPLICATIONSPeanut skins are waste products from peanut processing. As they are rich in phenolic substances, peanut skin extracts could become a cheap and easily available source of antioxidants, especially their methanol and ethyl acetate extracts. Their activity in lard and other bulk fats is only moderate, but they are efficient free radical scavengers and metal chelators. Therefore, they would be efficient in the stabilization of foods containing water and transient metal ions against autoxidation.
FEEDING AWAY INFLAMMATION – CONJUGATED LINOLEIC ACIDS DECREASE PANCREATIC PHOSPHOLIPASE A2 ACTIVITY*
Authors: STACHOWSKA EWA , DZIEDZIEJKO VIOLETTA , SAFRANOW KRZYSZTOF , JAKUBOWSKA KATARZYNA , OLSZEWSKA MARIA , BOBER JOANNA , CHLUBEK DARIUSZ 
Published: August 2007

ABSTRACT Conjugated linoleic acids (CLAs) are positional and geometric isomers of linoleic acid derived from food, mainly from milk and meat products. CLAs are ligands of peroxisome proliferator‐activated gamma receptors. Phospholipases A2 (PLA2) represent a diverse group of enzymes that catalyze the hydrolysis of ester bonds at the sn‐2 position of membrane phospholipids and release fatty acids and lysophospholipids. The objective of the study was to answer the question whether the release of linoleic acid by pancreatic PLA2 may change in the CLA‐containing environment. In this study, linoleic acid released by pancreatic PLA2 was a substrate for purified lipoxygenase – an enzyme converting it into hydroxylated derivatives including 9‐ and 13‐hydroxyoctadecadienoic acid (9‐,13‐HODE). In this method, the activity of PLA2 was determined by high‐performance liquid chromatography. In vitro incubation of hog PLA2 with CLA contributed to a noticeable fall in the synthesis of HODEs (P = 0.003; Kruskal–Wallis test). The concentration of HODEs decreased by 40.2% (for the cis‐9, trans‐11 CLA isomer; P = 0.007, Mann–Whitney test, n = 5) and by 27% (for the trans‐10, cis‐12 CLA isomer; P = 0.007, Mann–Whitney test, n = 5) as compared with the control (enzyme incubated without CLA). The inhibition exerted by cis‐9, trans‐11 CLA isomer was significantly greater than that by trans‐10, cis‐12 CLA isomer (P = 0.032, Mann–Whitney test, n = 5).PRACTICAL APPLICATIONSThis study is an attempt to clarify the response to the question whether some food ingredients such as conjugated linoleic acid (CLA) may be useful as an agent supporting the treatment of gastrointestinal disorders. It was observed under in vitro conditions that CLA isomers inhibited the phosphatidylcholine hydrolysis. By using purified enzymes, CLA was shown to contribute to local reduction of availability of linoleic acid and its metabolites (9‐ and 13‐hydroxyoctadecadienoic acid) through inhibition of phospholipid hydrolysis.
Effect of Biofilm Formation by
Pseudoalteromonas spongiae
on Induction of Larval Settlement of the Polychaete
Hydroides elegans
Authors: Huang Yi-Li , Dobretsov Sergey , Xiong Hairong , Qian Pei-Yuan 
Published: August 2007

ABSTRACT

The effects of culture conditions and chloramphenicol treatment on the induction of the marine bacterium
Pseudoalteromonas spongiae
to larval settlement of
Hydroides elegans
were investigated. The results showed that
P. spongiae
cells grown in the medium containing both yeast extract and peptone (YP-grown
P. spongiae
) was highly inductive to larval settlement, whereas
P. spongiae
cells grown in the medium containing only peptone (P-grown
P. spongiae
) or YP-grown
P. spongiae
cells treated with chloramphenicol at the onset of biofilm development (YPC-grown
P. spongiae
) did not induce larval settlement. Analysis of biofilm formation, biofilm structure, and the surface protein profile indicated that only the induction-capable YP-grown
P. spongiae
formed a well-developed biofilm, while the P-grown
P. spongiae
and the YPC-grown
P. spongiae
did not. We report here for the first time that bacterial biofilm formation was associated with its induction of larval settlement.
Influence of Lactic Acid Bacteria on Longevity ofCaenorhabditis elegansand Host Defense againstSalmonella entericaSerovar Enteritidis
Authors: Ikeda Takanori , Yasui Chikako , Hoshino Kaori , Arikawa Kentaro , Nishikawa Yoshikazu 
Published: August 2007

ABSTRACTThis study aimed to develop a convenient model to investigate the senescence of host defenses and the influence of food and nutrition. A small soil nematode,Caenorhabditis elegans, was grown for 3 days from hatching on a lawn ofEscherichia coliOP50 as the normal food source, and subsequently some of the nematodes were fed lactic acid bacteria (LAB). The life spans of worms fed LAB were significantly longer than the life spans of those fed OP50. To investigate the effect of age on host defenses, 3- to 7-day-old worms fed OP50 were transferred onto a lawn ofSalmonella entericaserovar Enteritidis for infection. The nematodes died over the course of several days, and the accumulation of salmonella in the intestinal lumen suggested that the worms were infected. The 7-day-old worms showed a higher death rate during the 5 days after infection than nematodes infected at the age of 3 days; no clear difference was observed when the worms were exposed to OP50. We then investigated whether the LAB could exert probiotic effects on the worms' host defenses and improve life span. Seven-day-old nematodes fed LAB from the age of 3 days were more resistant to salmonella than worms fed OP50 until they were infected with salmonella. This study clearly showed that LAB can enhance the host defense ofC. elegansand prolong life span. The nematode appears to be an appropriate model for screening useful probiotic strains or dietetic antiaging substances.
Influence of Antibiotic Selection on Genetic Composition of
Escherichia coli
Populations from Conventional and Organic Dairy Farms
Authors: Walk Seth T. , Mladonicky Janice M. , Middleton Jaclyn A. , Heidt Anthony J. , Cunningham Julie R. , Bartlett Paul , Sato Kenji , Whittam Thomas S. 
Published: August 2007

ABSTRACT

The widespread agricultural use of antimicrobials has long been considered a crucial influence on the prevalence of resistant genes and bacterial strains. It has been suggested that antibiotic applications in agricultural settings are a driving force for the development of antimicrobial resistance, and epidemiologic evidence supports the view that there is a direct link between resistant human pathogens, retail produce, farm animals, and farm environments. Despite such concerns, little is understood about the population processes underlying the emergence and spread of antibiotic resistance and the reversibility of resistance when antibiotic selective pressure is removed. In this study, hierarchical log-linear modeling was used to assess the association between farm type (conventional versus organic), age of cattle (calf versus cow), bacterial phenotype (resistant versus susceptible), and the genetic composition of
Escherichia coli
populations (
E. coli
Reference Collection [ECOR] phylogroup A, B1, B2, or D) among 678 susceptible and resistant strains from a previously published study of 60 matched dairy farms (30 conventional and 30 organic) in Wisconsin. The analysis provides evidence for clonal resistance (ampicillin resistance) and genetic hitchhiking (tetracycline resistance [Tet
r
]), estimated the rate of compositional change from conventional farming to organic farming (mean, 8 years; range, 3 to 15 years), and discovered a significant association between low multidrug resistance, organic farms, and strains of the numerically dominant phylogroup B1. These data suggest that organic farming practices not only change the frequency of resistant strains but also impact the overall population genetic composition of the resident
E. coli
flora. In addition, the results support the hypothesis that the current prevalence of Tet
r
loci on dairy farms has little to do with the use of this antibiotic.
The Termite Group I Phylum Is Highly Diverse and Widespread in the Environment
Authors: Herlemann Daniel P. R. , Geissinger Oliver , Brune Andreas 
Published: August 2007

ABSTRACT
The bacterial candidate phylum Termite Group I (TG-1) presently consists mostly of “Endomicrobia,” which are endosymbionts of flagellate protists occurring exclusively in the hindguts of termites and wood-feeding cockroaches. Here, we show that public databases contain many, mostly undocumented 16S rRNA gene sequences from other habitats that are affiliated with the TG-1 phylum but are only distantly related to “Endomicrobia.” Phylogenetic analysis of the expanded data set revealed several diverse and deeply branching lineages comprising clones from many different habitats. In addition, we designed specific primers to explore the diversity and environmental distribution of bacteria in the TG-1 phylum.
Mutagenesis of the “Leucine Gate” To Explore the Basis of Catalytic Versatility in Soluble Methane Monooxygenase
Authors: Borodina Elena , Nichol Tim , Dumont Marc G. , Smith Thomas J. , Murrell J. Colin 
Published: August 2007

ABSTRACT
Soluble methane monooxygenase (sMMO) from methane-oxidizing bacteria is a multicomponent nonheme oxygenase that naturally oxidizes methane to methanol and can also cooxidize a wide range of adventitious substrates, including mono- and diaromatic hydrocarbons. Leucine 110, at the mouth of the active site in the α subunit of the hydroxylase component of sMMO, has been suggested to act as a gate to control the access of substrates to the active site. Previous crystallography of the wild-type sMMO has indicated at least two conformations of the enzyme that have the “leucine gate” open to different extents, and mutagenesis of homologous enzymes has indicated a role for this residue in the control of substrate range and regioselectivity with aromatic substrates. By further refinement of the system for homologous expression of sMMO that we developed previously, we have been able to prepare a range of site-directed mutations at position 110 in the α subunit of sMMO. All the mutants (with Gly, Cys, Arg, and Tyr, respectively, at this position) showed relaxations of regioselectivity compared to the wild type with monoaromatic substrates and biphenyl, including the appearance of new products arising from hydroxylation at the 2- and 3- positions on the benzene ring. Mutants with the larger Arg and Trp residues at position 110 also showed shifts in regioselectivity during naphthalene hydroxylation from the 2- to the 1- position. No evidence that mutagenesis of Leu 110 could allow very large substrates to enter the active site was found, however, since the mutants (like the wild type) were inactive toward the triaromatic hydrocarbons anthracene and phenanthrene. Thus, our results indicate that the “leucine gate” in sMMO is more important in controlling the precision of regioselectivity than the sizes of substrates that can enter the active site.
Subtypes of the Plasmid-Encoded Serine Protease EspP in Shiga Toxin-Producing
Escherichia coli
: Distribution, Secretion, and Proteolytic Activity
Authors: Brockmeyer Jens , Bielaszewska Martina , Fruth Angelika , Bonn Marie Luise , Mellmann Alexander , Humpf Hans-Ulrich , Karch Helge 
Published: August 2007

ABSTRACT

We investigated the prevalence, distribution, and structure of
espP
in Shiga toxin-producing
Escherichia coli
(STEC) and assessed the secretion and proteolytic activity of the encoded autotransporter protein EspP (extracellular serine protease, plasmid encoded).
espP
was identified in 56 of 107 different STEC serotypes. Sequencing of a 3,747-bp region of the 3,900-bp
espP
gene distinguished four alleles (
espP
α,
espP
β,
espP
γ, and
espP
δ), with 99.9%, 99.2%, 95.3%, and 95.1% homology, respectively, to
espP
of
E. coli
O157:H7 strain EDL933. The
espP
β,
espP
γ, and
espP
δ genes contained unique insertions and/or clustered point mutations that enabled allele-specific PCRs; these demonstrated the presence of
espP
α,
espP
β,
espP
γ, and
espP
δ in STEC isolates belonging to 17, 16, 15, and 8 serotypes, respectively. Among four subtypes of EspP encoded by these alleles, EspPα (produced by enterohemorrhagic
E. coli
[EHEC] O157:H7 and the major non-O157 EHEC serotypes) and EspPγ cleaved pepsin A, human coagulation factor V, and an oligopeptide alanine-alanine-proline-leucine-para-nitroaniline, whereas EspPβ and EspPδ either were not secreted or were proteolytically inactive. The lack of proteolysis correlated with point mutations near the active serine protease site. We conclude that
espP
is widely distributed among STEC strains and displays genetic heterogeneity, which can be used for subtyping and which affects EspP activity. The presence of proteolytically active EspP in EHEC serogroups O157, O26, O111, and O145, which are bona fide human pathogens, suggests that EspP might play a role as an EHEC virulence factor.
Multilocus Sequence Typing ofLactobacillus caseiReveals a Clonal Population Structure with Low Levels of Homologous Recombination
Authors: Diancourt Laure , Passet Virginie , Chervaux Christian , Garault Peggy , Smokvina Tamara , Brisse Sylvain 
Published: August 2007

ABSTRACTRobust genotyping methods forLactobacillus caseiare needed for strain tracking and collection management, as well as for population biology research. A collection of 52 strains initially labeledL. caseiorLactobacillus paracaseiwas first subjected torplBgene sequencing together with reference strains ofLactobacillus zeae,Lactobacillus rhamnosus, and other species. Phylogenetic analysis showed that all 52 strains belonged to a single compactL. casei-L. paracaseisequence cluster, together with strain CIP107868 (= ATCC 334) but clearly distinct fromL. rhamnosusand from a cluster withL. zeaeand CIP103137T(= ATCC 393T). The strains were genotyped using amplified fragment length polymorphism, multilocus sequence typing based on internal portions of the seven housekeeping genesfusA,ileS,lepA,leuS,pyrG,recA, andrecG, and tandem repeat variation (multilocus variable-number tandem repeats analysis [MLVA] using nine loci). Very high concordance was found between the three methods. Although amounts of nucleotide variation were low for the seven genes (π ranging from 0.0038 to 0.0109), 3 to 12 alleles were distinguished, resulting in 31 sequence types. One sequence type (ST1) was frequent (17 strains), but most others were represented by a single strain. Attempts to subtype ST1 strains by MLVA, ribotyping, clustered regularly interspaced short palindromic repeat characterization, and single nucleotide repeat variation were unsuccessful. We found clear evidence for homologous recombination during the diversification ofL. caseiclones, including a putative intragenic import of DNA into one strain. Nucleotides were estimated to change four times more frequently by recombination than by mutation. However, statistical congruence between individual gene trees was retained, indicating that recombination is not frequent enough to disrupt the phylogenetic signal. The developed multilocus sequence typing scheme should be useful for future studies ofL. caseistrain diversity and evolution.
The Diversity of Coliphages and Coliforms in Horse Feces Reveals a Complex Pattern of Ecological Interactions
Authors: Golomidova Alla , Kulikov Eugene , Isaeva Alina , Manykin Anatoly , Letarov Andrey 
Published: August 2007

ABSTRACT

The diversity of coliphages and indigenous coliform strains (ICSs) simultaneously present in horse feces was investigated by culture-based and molecular methods. The richness of coliforms (as estimated by the Chao1 method) is about 1,000 individual ICSs distinguishable by genomic fingerprinting present in a single sample of feces. This unexpectedly high value indicates that some factor limits the competition of coliform bacteria in the horse gut microbial system. In contrast, the diversity of phages active against any selected ICS is generally limited to one to three viral genotypes present in the sample. The sensitivities of different ICSs to simultaneously present coliphages overlap only slightly; the phages isolated from the same sample on different ICSs are usually unrelated. As a result, the titers of phages in fecal extract as determined for different
Escherichia coli
strains and ICSs may differ by several orders of magnitude. Summarizing all the data, we propose that coliphage infection may provide a selection pressure that maintains the high level of coliform diversity, restricting the possibility of a few best competitors outgrowing other ICSs. We also observed high-magnitude temporal variations of coliphage titers as determined using an
E. coli
C600 test culture in the same animal during a 16-day period of monitoring. No correlation with total coliform count was observed. These results are in good agreement with our hypothesis.
Effect of Biotic and Abiotic Factors on In Vitro Proliferation, Encystment, and Excystment of
Pfiesteria piscicida
Authors: Saito Keiko , Drgon Tomás , Krupatkina Danara N. , Drgonova Jana , Terlizzi Daniel E. , Mercer Natalia , Vasta Gerardo R. 
Published: August 2007

ABSTRACT

Pfiesteria
spp. are mixotrophic armored dinoflagellates populating the Atlantic coastal waters of the United States. They have been a focus of intense research due to their reported association with several fish mortality events. We have now used a clonal culture of
Pfiesteria piscicida
and several new environmental isolates to describe growth characteristics, feeding, and factors contributing to the encystment and germination of the organism in both laboratory and environmental samples. We also discuss applied methods of detection of the different morphological forms of
Pfiesteria
in environmental samples. In summary,
Pfiesteria
, when grown with its algal prey,
Rhodomonas
sp., presents a typical growth curve with lag, exponential, and stationary phases, followed by encystment. The doubling time in exponential phase is about 12 h. The profiles of proliferation under a standard light cycle and in the dark were similar, although the peak cell densities were markedly lower when cells were grown in the dark. The addition of urea, chicken manure, and soil extracts did not enhance
Pfiesteria
proliferation, but crude unfiltered spent aquarium water did. Under conditions of food deprivation or cold (4°C),
Pfiesteria
readily formed harvestable cysts that were further analyzed by PCR and scanning electron microscopy. The germination of
Pfiesteria
cysts in environmental sediment was enhanced by the presence of live fish: dinospores could be detected 13 to 15 days earlier and reached 5- to 10-times-higher peak cell densities with live fish than with artificial seawater or f/2 medium alone. The addition of ammonia, urea, nitrate, phosphate, or surprisingly, spent fish aquarium water had no effect.
Combined Imaging of Bacteria and Oxygen in Biofilms
Authors: Kühl Michael , Rickelt Lars F. , Thar Roland 
Published: August 2007

ABSTRACT

Transparent sensors for microscopic O
2
imaging were developed by spin coating an ultrathin (<1- to 2-μm) layer of a luminescent O
2
indicator onto coverslips. The sensors showed (i) an ideal Stern-Volmer quenching behavior of the luminescence lifetime towards O
2
levels, (ii) homogeneous measuring characteristics over the sensor surface, and (iii) a linear decline of luminescence lifetime with increasing temperature. When a batch of such coverslip sensors has been characterized, their use is thus essentially calibration free at a known temperature. The sensors are easy to use in flow chambers and other growth devices used in microbiology. We present the first application for combined imaging of O
2
and bacteria in a biofilm flow chamber mounted on a microscope equipped with a spinning-disk confocal unit and a luminescence lifetime camera system.