bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Ultrastructural Characterization of the Ooplasm in Ovarian Follicles of the Immature Ostrich (Struthio camelus)
Authors: Madekurozwa M.‐C. , Kimaro W. H. 
Published: January 2008

SummaryPrimordial, pre‐vitellogenic and vitellogenic follicles were present in the ovary of the immature ostrich. The oocytes of these follicles were composed of a nucleus surrounded by ooplasm. Central, intermediate and cortical regions formed the ooplasm. The organelles present in these ooplasmic regions varied depending on the stage of follicular development. In primordial and small pre‐vitellogenic (100–150 μm in diameter) follicles the central region of the ooplasm was dominated by an accumulation of organelles, which formed Balbiani’s vitelline body. In contrast, the central region in vitellogenic follicles was filled with numerous large yolk spheres, many of which contained lining bodies. Numerous lipid droplets interspersed with mitochondria and small yolk spheres formed the intermediate ooplasmic region in primordial and small pre‐vitellogenic follicles. In large pre‐vitellogenic (150–400 μm in diameter) and vitellogenic follicles the intermediate region contained a greater density of mitochondria and small yolk spheres. Small yolk spheres were observed in the cortical region of pre‐vitellogenic follicles. An interesting feature of the cortical region in vitellogenic follicles was the frequent occurrence of Golgi complexes. The results of the study indicate that although the ovarian follicles in the immature ostrich are not ovulated, the components and composition of the ooplasm are similar to those observed in the mature follicles of other avian species.
Bilateral Lymphangiomatous Testicular Lesions in a Lamb
Authors: Brown P , Smith K , Bazely K , Glover M , Barr F 
Published: January 2008

ContentsBilateral testicular enlargement was recognized in a young lamb; both gonads were largely replaced by a mass composed of multiple cystic spaces. Positive immunohistochemical staining for factor VIII‐related protein indicated that the cysts were lined by endothelial cells. The precise nature and origin of the lesions is unclear; they might represent hamartomas or benign tumours or may be a result of lymphatic obstruction.
EhaA is a novel autotransporter protein of enterohemorrhagic Escherichia coli O157:H7 that contributes to adhesion and biofilm formation
Authors: Wells Timothy J. , Sherlock Orla , Rivas Lucy , Mahajan Arvind , Beatson Scott A. , Torpdahl Mia , Webb Richard I. , Allsopp Luke P. , Gobius Kari S. , Gally David L. , Schembri Mark A. 
Published: January 2008

SummaryAutotransporter (AT) proteins have been identified in many Gram‐negative pathogens and are unique in that their primary sequence is sufficient to direct their transport across the bacterial membrane system. Where characterized they are uniformly associated with virulence. Using conserved AT motifs as a search tool, four putative AT proteins were identified in the Enterohemorrhagic Escherichia coli O157:H7 EDL933 genome. The genes encoding these proteins (z0402/ehaA, z0469/ehaB, z3487/ehaC and z3948/ehaD) were PCR amplified, cloned and expressed in an E. coli K‐12 MG1655flu background. Preliminary characterization revealed that ehaA, ehaB and ehaD encode proteins associated with increased biofilm formation. One of these genes (ehaA) resides on a genomic island in E. coli O157:H7 strains EDL933 and Sakai. Over‐expression of EhaA in E. coli K‐12 demonstrated it is located at the cell surface and resulted in the formation of large cell aggregates, promoted significant biofilm formation and mediated adhesion to primary epithelial cells of the bovine terminal rectum. The expression of ehaA was demonstrated in E. coli EDL933 by RT‐PCR. An EhaA‐specific antibody revealed the EhaA protein was expressed in 24/50 generic Shiga toxin‐producing E. coli (STEC) strains of various serotypes including O157:H7. However, the deletion of ehaA from E. coli EDL933 and a STEC strain from serotype O111:H– did not affect biofilm growth. Our results suggest that EhaA may contribute to adhesion, colonization and biofilm formation by E. coli O157:H7 and possibly other STEC serotypes.
Expression and use of superfolder green fluorescent protein at high temperatures in vivo: a tool to study extreme thermophile biology
Authors: Cava Felipe , De Pedro Miguel Angel , Blas‐Galindo Emilio , Waldo Geoffrey S. , Westblade Lars F. , Berenguer José 
Published: January 2008

SummarySuperfolder GFP (sGFP) is a variant of the Green Fluorescent Protein that folds efficiently when fused to poorly folded proteins. In this study, we show that sGFP, but not enhanced GFP, is functional in vivo at 70°C in the extreme thermophile Thermus thermophilus (Tth); thus, permitting the use of sGFP as a localization tag in vivo. We created a suite of plasmids that allow the expression of carboxy‐terminal sGFP fusion proteins in both Escherichia coli and Tth. In order to demonstrate the facility of sGFP as an in vivo localization tag in Tth, we tagged GroES (the small subunit of the bacterial GroES/GroEL chaperone), NarC (a membrane component of the nitrate respiration apparatus) and PhoA (a TAT‐secreted periplasmic protein), and visualized the distribution of the sGFP fusion proteins using confocal microscopy. Fusions to NarC and PhoA produced enzymatically active proteins that complemented both the narC and the phoA strains respectively. Observation of the distribution of the GroES‐sGFP protein by confocal microscopy revealed a homogeneous fluorescence in the cells, which is in full agreement with the cytoplasmic nature of GroES, whereas the NarC‐sGFP protein was localized to the membrane. Finally, a combination of confocal microscopy and biochemistry revealed that PhoA is localized in the periplasm. We suggest that sGFP will be broadly applicable in characterizing various extreme thermophile systems.
Global features of the Alcanivorax borkumensis SK2 genome
Authors: Reva Oleg N. , Hallin Peter F. , Willenbrock Hanni , Sicheritz‐Ponten Thomas , Tümmler Burkhard , Ussery David W. 
Published: January 2008

SummaryThe global feature of the completely sequenced Alcanivorax borkumensis SK2 type strain chromosome is its symmetry and homogeneity. The origin and terminus of replication are located opposite to each other in the chromosome and are discerned with high signal to noise ratios by maximal oligonucleotide usage biases on the leading and lagging strand. Genomic DNA structure is rather uniform throughout the chromosome with respect to intrinsic curvature, position preference or base stacking energy. The orthologs and paralogs of A. borkumensis genes with the highest sequence homology were found in most cases among γ‐Proteobacteria, with Acinetobacter and P. aeruginosa as closest relatives. A. borkumensis shares a similar oligonucleotide usage and promoter structure with the Pseudomonadales. A comparatively low number of only 18 genome islands with atypical oligonucleotide usage was detected in the A. borkumensis chromosome. The gene clusters that confer the assimilation of aliphatic hydrocarbons, are localized in two genome islands which were probably acquired from an ancestor of the Yersinia lineage, whereas the alk genes of Pseudomonas putida still exhibit the typical Alcanivorax oligonucleotide signature indicating a complex evolution of this major hydrocarbonoclastic trait.
The characterization of functions involved in the establishment and maturation of Klebsiella pneumoniae in vitro biofilm reveals dual roles for surface exopolysaccharides
Authors: Balestrino Damien , Ghigo Jean‐Marc , Charbonnel Nicolas , Haagensen Janus A. J. , Forestier Christiane 
Published: January 2008

SummaryThe ability to form biofilm is seen as an increasingly important colonization strategy among both pathogenic and environmental Klebsiella pneumoniae strains. The aim of the present study was to identify abiotic surface colonization factors of K. pneumoniae using different models at different phases of biofilm development. A 2200 K. pneumoniae mutant library previously obtained by signature‐tagged mutagenesis was screened in static and dynamic culture models to detect clones impaired at early and/or mature stages of biofilm formation. A total of 28 mutants were affected during late phases of biofilm formation, whereas 16 mutants displayed early adhesion defect. These mutants corresponded to genes involved in potential cellular and DNA metabolism pathways and to membrane transport functions. Eight mutants were deficient in capsule or LPS production. Gene disruption and microscopic analyses showed that LPS is involved in initial adhesion on both glass and polyvinyl‐chloride and the capsule required for the appropriate initial coverage of substratum and the construction of mature biofilm architecture. These results give new insight into the bacterial factors sequentially associated with the ability to colonize an abiotic surface and reveal the dual roles played by surface exopolysaccharides during K. pneumoniae biofilm formation.
Co‐occurrence of β‐N‐methylamino‐l‐alanine, a neurotoxic amino acid with other cyanobacterial toxins in British waterbodies, 1990–2004
Authors: Metcalf James S. , Banack Sandra Anne , Lindsay Jaime , Morrison Louise F. , Cox Paul Alan , Codd Geoffrey A. 
Published: January 2008

SummaryThe neurotoxic amino acid, β‐N‐methylamino‐l‐alanine, was found to be present in all of 12 analysed samples of cyanobacterial blooms, scums and mats, which had been collected in seven years between 1990 and 2004 inclusive and stored at −20°C. BMAA identification was by high performance liquid chromatography with fluorescence detection and by triple quadrapole mass spectrometry after derivatization. The samples originated from 11 freshwater lakes and 1 brackish waterbody, used either for drinking water, recreation, or both. BMAA was present at between 8 and 287 μg g−1 cyanobacterial dry weight and was present as both the free amino acid and associated with precipitated proteins. Ten of the samples contained additional cyanotoxins (including microcystins, anatoxin‐a, nodularin and saxitoxin) at the time of sample collection. Five of the samples were associated with animal deaths, attributable at the time of sample collection, to microcystins, nodularin or anatoxin‐a. The data demonstrate the presence of BMAA by high performance liquid chromatography and mass spectrometry in a diverse range of cyanobacterial bloom samples from high resource waterbodies. Furthermore, samples collected over several years shows that BMAA can co‐occur with other known cyanotoxins in such waterbodies. Health risk assessment of cyanobacterial BMAA in waterbodies is suggested.
Major differences of bacterial diversity and activity inside and outside of a natural iron‐fertilized phytoplankton bloom in the Southern Ocean
Authors: West Nyree J. , Obernosterer Ingrid , Zemb Olivier , Lebaron Philippe 
Published: January 2008

SummaryOne of the first comparisons of a natural iron fertilized bloom with a high‐nutrient low‐chlorophyll (HNLC) site was undertaken during the Kerguelen ocean and plateau compared study (KEOPS) cruise. To understand better the bacteria–phytoplankton relationship in the context of natural iron fertilization, bacterial diversity and activity was investigated in the bloom and in the adjacent HNLC region by 16S rDNA clone libraries and by single strand conformation polymorphism (SSCP) analysis. Both libraries were dominated by Alphaproteobacteria, Gammaproteobacteria and the Cytophaga‐Flavobacteria‐Bacteroides group. Cluster analysis at 99% sequence similarity yielded several microdiverse clusters and revealed striking differences between the two libraries. In the bloom, the dominant operational taxonomic units (OTUs) were the Roseobacter NAC11‐7 cluster, SAR92 and a Cytophaga‐Flavobacteria‐Bacteroides cluster related to the agg58 group, whereas in the HNLC region, SAR11, Roseobacter RCA and Polaribacter dominated. SSCP analysis of 16S rDNA and 16S rRNA revealed contrasting dynamics of three different Roseobacter OTUs. Roseobacter NAC11‐7 and NAC11‐6 had higher relative abundances and activities in the bloom compared with the HNLC site and NAC11‐6 was only detected at the decline of the bloom concomitant with a shift in phytoplankton composi tion. In contrast, Roseobacter RCA was relatively abundant and active both inside and outside of the bloom. These results suggest that the different OTUs within the Roseobacter group represent functional groups that each play an important role in the cycling of carbon.
Think big – giant genes in bacteria
Authors: Reva Oleg , Tümmler Burkhard 
Published: January 2008

SummaryLong genes should be rare in archaea and eubacteria because of the demanding costs of time and resources for protein production. The search in 580 sequenced prokaryotic genomes, however, revealed 0.2% of all genes to be longer than 5 kb (absolute number: 3732 genes). Eighty giant bacterial genes of more than 20 kb in length were identified in 47 taxa that belong to the phyla Thermotogae (1), Chlorobi (3), Planctomycetes (1), Cyanobacteria (2), Firmicutes (7), Actinobacteria (9), Proteobacteria (23) or Euryarchaeota (1) (number of taxa in brackets). Giant genes are strain‐specific, differ in their tetranucleotide usage from the bulk genome and occur preferentially in non‐pathogenic environmental bacteria. The two longest bacterial genes known to date were detected in the green sulfur bacterium Chlorobium chlorochromatii CaD3 encoding proteins of 36 806 and 20 647 amino acids, being surpassed in length only by the human titin coding sequence. More than 90% of bacterial giant genes either encode a surface protein or a polyketide/non‐ribosomal peptide synthetase. Most surface proteins are acidic, threonine‐rich, lack cystein and harbour multiple amino acid repeats. Giant proteins increase bacterial fitness by the production of either weapons towards or shields against animate competitors or hostile environments.
Phenazines and biosurfactants interact in the biological control of soil‐borne diseases caused by Pythium spp.
Authors: Perneel Maaike , D'hondt Liesbet , De Maeyer Katrien , Adiobo Amayana , Rabaey Korneel , Höfte Monica 
Published: January 2008

SummaryIn this study, the putative role of phenazines and rhamnolipid‐biosurfactants, antagonistic metabolites produced by Pseudomonas aeruginosa PNA1, was tested in the biological control of Pythium splendens on bean (Phaseolus vulgaris L) and Pythium myriotylum on cocoyam (Xanthosoma sagittifolium L Schott). A rhamnolipid‐deficient and a phenazine‐deficient mutant of PNA1 were used either separately or jointly in plant experiments. When the mutants were applied separately, no disease‐suppressive effect was observed, although both mutants still produced one of the antagonistic compounds (phenazines or rhamnolipids). When the mutants were concurrently introduced in the soil, the biocontrol activity was restored to wild‐type levels. Bean seeds developed significantly less pre‐emergence damping‐off caused by P. splendens when treated with a mixture of purified phenazine‐1‐carboxamide and rhamnolipids than with any of the chemicals alone. When phenazines and rhamnolipids were combined at concentrations that had no observable effects when the metabolites were applied separately, mycelial growth of P. myriotylum was significantly reduced. In addition, microscopic analysis revealed substantial vacuolization and disintegration of Pythium hyphae after incubation in liquid medium amended with both metabolites. Results of this study indicate that phenazines and biosurfactants are acting synergistically in the control of Pythium spp.
Cultivation of a thermophilic ammonia oxidizing archaeon synthesizing crenarchaeol
Authors: De La Torre José R. , Walker Christopher B. , Ingalls Anitra E. , Könneke Martin , Stahl David A. 
Published: January 2008

SummaryThe widespread occurrence and diversity of ammonia oxidizing Archaea suggests their contribution to the nitrogen cycle is of global significance. Their distribution appeared limited to low‐ and moderate‐temperature environments until the recent finding of a diagnostic membrane lipid, crenarchaeol, in terrestrial hot springs. We report here the cultivation of a thermophilic nitrifier (‘Candidatus Nitrosocaldus yellowstonii’), an autotrophic crenarchaeote growing up to 74°C by aerobic ammonia oxidation. The major core lipid of this archaeon growing at 72°C is crenarchaeol, providing the first direct evidence for its synthesis by a thermophile. These findings greatly extend the upper temperature limit of nitrification and document that the capacity for ammonia oxidation is broadly distributed among the Crenarchaeota.
Ecology of type II secretion in marine gammaproteobacteria
Authors: Evans Flavia F. , Egan Suhelen , Kjelleberg Staffan 
Published: January 2008

SummaryCompelling findings on the direct association of the type II secretion (T2S) system with different ecological functions in marine bacteria have challenged the traditional view of the T2S pathway, the function of which has been mostly studied in pathogenic bacteria. The availability of a number of whole‐genome sequence data sets enabled the analysis of the genetic composition of the T2S system across a number of Vibrios and Alteromonads. The widespread Gammaproteobacteria, in particular the Alteromonadales and the Vibrionales group, are recognized to play significant roles in the cycling of nutrients in coastal and pelagic marine ecosystems and are also found associated with marine eukaryotes. The combined analysis of the role and the genetic composition of the T2S system in Gammaproteobacteria provides important evidence for the significance of the T2S pathway in the ecology of environmental bacteria.
The Effect of the Size of the Military on Stock Market Performance in the United States and the UK
Authors: DiPietro William R. , Anoruo Emmanuel , Sawhney Bansi 
Published: January 2008

SUMMARYThis paper uses regression analysis to investigate the relationship between military expenditure and stock market performance for the United States and the United Kingdom. Specifically, the study applies the Bierens‐Guo unit root procedures to ascertain the time series properties of the variables in the study. The standard OLS technique is employed to determine the influence of military expenditure on stock markets for the period 1914 through 2001. The results from the unit root tests indicate that the military expenditure, military personnel, stock market, and energy consumption series are level stationary. The results from the OLS equations suggest that military expenditure has significantly positive effect on stock market performance for the United States and the United Kingdom. The implication of this finding is that high‐income class and people in power are less likely to oppose increases in military spending even though such expenditures are not in the best interest of the society.
Is Contemporary Interest Rate in Conflict with Islamic Ethics?
Authors: Kula Erhun 
Published: January 2008

SUMMARYThis paper considers whether the modern interest rate theory is in conflict with Islamic values. Unfortunately, the issue is not sufficiently debated in economic and cognate literature and thus a mist surrounds the Islamic concept of interest (riba) and its use in the Moslem world that contains about 1.3 billion people and hundreds of billions of dollars of surplus funds. A substantial part of this money has not been made available to the commercial banking system as Islamists in particular keep their savings in the form of gold, precious stones or durable foreign currency, in residential or other safe places, believing that earning interest on savings is against the principles of Islam. This attitude by creating a shortage of funds for investment projects is hampering the economic development of many Moslem countries where standards of living are generally low. The finding of the paper is that only one component part of the time preference rate, namely pure time discount, may be objectionable from the Islamic as well as from secular viewpoints; the rest does not appear to be against Muslim ethics. However, a truly competitive financial market structure is likely to wipe away the excessive pure time discount rate leaving the market interest rate free from any objectionable parameter.
Macro‐Determinants of Gambling in Industrialized Nations
Authors: Pryor Frederic L. 
Published: January 2008

SUMMARYThis study investigates some of the macro‐determinants of commercial gambling in 21 industrialized nations. Of the possible economic determinants, two seem particularly important: the per capita income of the country since gambling represents a larger share of the income of low‐income people than high‐income people; and the general uncertainty of the economic environment, as measured by annual fluctuations in the GDP. Of the possible cultural determines, two also seem particularly important: the values held by the population, as measured by a factor analysis of a number of questions from the World Value Study; and the degree to which the society insures against risk through social welfare expenditures. For the OECD nations in the early part of the 21st century, all four variables prove to be significantly related to the ratio of gambling expenditures to disposable income.
Critical Legal Studies versus Critical Legal Theory: A Comment on Method
Authors: MUNGER FRANK , SERON CARROLL 
Published: January 2008

Over the last decade the Conference on Critical Legal Studies (CCLS) has rekindled an important debate about the study of legal ideologies. The work by scholars within this movement is provocative because it demands that we take seriously the contradictory needs and ideological parameters of liberal legalism. The growing body of work associated with this movement has not, however, included a criticism of the ideological underpinnings of legal methods in general and doctrinal analysis in particular. We begin with the premise that scholarship must include a self‐critical method.In Part I—The Political‐Economic Constraints of Liberal Legal Scholarship—we explore why questions of methods, i. e. of how one asks and answers questions, has not been a central issue within CCLS. In Part II—Reformulation of Method—we present a beginning toward a framework for developing a self‐critical method for understanding legal ideologies.
The Dilemmas of Legal Mobilization: Ideologies and Strategies of Mental Patient Liberation Groups
Authors: MILNER NEAL 
Published: January 2008

The decision to participate in the legal process depends in part upon the ideologies of the potential participants. The ideology that has dominated the rights movement during the past two decades is what Stuart Scheingold describes as the myth of rights. But participation in litigation, including rights evolution litigation, has also been colored by other and sometimes conflicting ideologies. Thus the mobilization of legal resources can be seen as the ways participants in litigation cope with multiple ideologies.This paper looks at the mental patient liberation movement in this way. That movement has been very much affected by a myth of rights ideology, as well as by a liberation ideology that is quite contradictory to the tenets of the myth of rights. The paper documents these ideologies, looks at the way the movement has tried to reconcile them, and shows how this problematic reconciliation affects the nature of mental health rights litigation.