bluuebunny/crossref_metadata_2025 huggingface dataset:
The uptake of radioactive phosphorus from host tissues and fluids by nematode parasites
Authors: Rogers W. P. , Lazarus Marian
Published: June 2009

1. Compared with the mammalian intestine, uterus and blood serum, the corresponding organs and perienteric fluid ofAscaris lumbricoideswere found to have a high phosphorus content. The muscle of the parasite, however, contained little more than half the phosphorus found in the mammalian muscle.

2.A. lumbricoidestook up inorganic ortho-phosphate largely or exclusively through the alimentary tract. Small amounts were taken up by the cuticle and the lateral line system, but did not appear to pass on to other tissues.

3.Nippostrongylus murisin the intestine of the rat took up radioactive phosphorus which had been injected into the host intramuscularly. When the host was dosedper osthe radioactivity appeared in the parasites at a lower concentration than in the host's small intestine.

4.Ascaridia gallifailed to show any radio-activity when host birds were injected intravenously with inorganic orthophosphate containing P32. A sudden rise and fall in the radioactivity of the parasites were found when host birds were dosedper os.

5. It is suggested that nematode parasites have a high demand for phosphate which they take up largelyper os. Ascaridia gallifeeds rapidly, but with poor phosphate absorption, on host gut contents.Nippostrongylus murisfeeds on host tissues. It is suggested that the different feeding habits ofN. murisandAscaridia gallimay have some relation to the efficacy of anthelmintics against these parasites.

The authors are indebted to Dr M. Kamen and Dr E. Reinhard of Washington University, St Louis, for a gift of radioactive phosphorus. Thanks are also due to Mr E. Parrish and Mr L. Turk of the McMaster Laboratory for their capable assistance.
On the gregarineLankesteria culicis(Ross), 1898, from the mosquitoAëdes(Finlaya)geniculatus(Olivier)
Authors: Ganapati P. N. , Tate P.
Published: June 2009

1. The morphology and life history of a gregarineLankesteria culicis(Ross), as it lives in the gut ofAëdes(Finlaya)geniculatus(Olivier), are described. The earlier stages are intra-epithelial in the fore and anterior mid-gut of the larvae. After a period of growth the trophozoites are liberated into the gut lumen where they attach themselves to the epithelium by a well-developed epimerite which functions as a sucker. Cyst formation and further stages in sporogony take place in the malpighian tubules when the larvae develop into the pupae. In the adult mosquito only ripe sporocysts are found, packed in the malpighian tubules and scattered in the hind-gut. The spores escape through the alimentary canal.

2. The systematic position ofLankesteriais reviewed. In view of its true dicystid nature, combining both acephaline and cephaline features, it is suggested that its proper systematic position would be in the dicystid family Lecudinidae Kamm emend. Reichenow, 1929, which includes all forms intermediate in position between the monocystids and the true tricystids.
Notes on the morphology and life history ofSchistocephalus solidus(Cestoda: Diphyllobothriidae)
Authors: Hopkins C. A. , Smyth J. D.
Published: June 2009

Schistocephalus solidusis a small avian pseudophyllidean cestode which, on account of its small size and the ease with which its plerocercoid may be cultured to maturityin vitro, has been used within recent years for the study of cestode physiology.
The structure of the adult and larval stages ofPlagiorchis (Multiglandularis) megalorchisn.nom. from the turkey and an experimental demonstration of the life history
Authors: Rees Gwendolen
Published: June 2009

1. Large numbers ofPlagiorchis (M.) megalorchisn.nom. were found in the intestine of four turkey poults of a total of thirteen which had died on a farm in Radnorshire. Presumably the presence of the parasites was the cause of death.

2. The anatomy of the adult worm is described.

3. The first intermediate host of the parasite isLymnaea pereger, and the second intermediate host any of the following species of insect larvae:Chironomus ripariusMeigen,Culicoides stigmaMeigen,Culicoides nubeculosusMeigen andAnatopynia (Psectrotanypus) variusFabr.

4. The larval stages of the worm are described.

5. The life cycle has been demonstrated experimentally by the feeding of insect larvae containing encysted cercariae to turkey poults.

6. The turkey is probably not the normal host ofPlagiorchis (M.) megalorchis. It is most likely that it occurs naturally in some species of wild bird, but this is not yet known.
β-ionone activates and bleaches visual pigment in salamander photoreceptors
Authors: ISAYAMA TOMOKI , McCABE ENGLAND S.L. , CROUCH R.K. , ZIMMERMAN A.L. , MAKINO C.L.
Published: June 2009

Vision begins with photoisomerization of 11-cis retinal to the all-trans conformation within the chromophore-binding pocket of opsin, leading to activation of a biochemical cascade. Release of all-trans retinal from the binding pocket curtails but does not fully quench the ability of opsin to activate transducin. All-trans retinal and some other analogs, such as β-ionone, enhance opsin’s activity, presumably on binding the empty chromophore-binding pocket. By recording from isolated salamander photoreceptors and from patches of rod outer segment membrane, we now show that high concentrations of β-ionone suppressed circulating current in dark-adapted green-sensitive rods by inhibiting the cyclic nucleotide-gated channels. There were also decreases in circulating current and flash sensitivity, and accelerated flash response kinetics in dark-adapted blue-sensitive (BS) rods and cones, and in ultraviolet-sensitive cones, at concentrations too low to inhibit the channels. These effects persisted in BS rods even after incubation with 9-cis retinal to ensure complete regeneration of their visual pigment. After long exposures to high concentrations of β-ionone, recovery was incomplete unless 9-cis retinal was given, indicating that visual pigment had been bleached. Therefore, we propose that β-ionone activates and bleaches some types of visual pigments, mimicking the effects of light.
Phylogeny of proteolipid proteins: divergence, constraints, and the evolution of novel functions in myelination and neuroprotection
Authors: Möbius Wiebke , Patzig Julia , Nave Klaus-Armin , Werner Hauke B.
Published: June 2009

The protein composition of myelin in the central nervous system (CNS) has changed at the evolutionary transition from fish to tetrapods, when a lipid-associated transmembrane-tetraspan (proteolipid protein, PLP) replaced an adhesion protein of the immunoglobulin superfamily (P0) as the most abundant constituent. Here, we review major steps of proteolipid evolution. Three paralog proteolipids (PLP/DM20/DMα, M6B/DMγ and the neuronal glycoprotein M6A/DMβ) exist in vertebrates from cartilaginous fish to mammals, and one (M6/CG7540) can be traced in invertebrate bilaterians including the planktonic copepod Calanus finmarchicus that possess a functional myelin equivalent. In fish, DMα and DMγ are coexpressed in oligodendrocytes but are not major myelin components. PLP emerged at the root of tetrapods by the acquisition of an enlarged cytoplasmic loop in the evolutionary older DMα/DM20. Transgenic experiments in mice suggest that this loop enhances the incorporation of PLP into myelin. The evolutionary recruitment of PLP as the major myelin protein provided oligodendrocytes with the competence to support long-term axonal integrity. We suggest that the molecular shift from P0 to PLP also correlates with the concentration of adhesive forces at the radial component, and that the new balance between membrane adhesion and dynamics was favorable for CNS myelination.
The Opisthokonta and the Ecdysozoa may be clades: An update on Philip et al. (2005)
Authors: Prous Marko
Published: June 2009

To test the monophyly of Opisthokonta (animal-fungal clade) and Ecdysozoa (nematode-arthropod clade), Philip et al [Mol. Biol. Evol. 22: 1175–1184 (2005)] used sequence data from 10 eukaryotic genomes (an alveolate, a plant, two ascomycetous yeasts, a nematode, two dipterans, and three vertebrates). Strict criteria were used to select genes for phylogenetic analyses: single-gene families were identified and from these families, genes capable of recovering the uncontroversial parts of the phylogenetic tree (for example animal and vertebrate monophyly) were selected. Only five single-copy genes were found to be universally distributed across the analyzed taxa and capable of recovering all the uncontroversial parts of the tree. Phylogenetic analyses of those genes gave strong support for plant-animal grouping and the monophyly of Coelomata (vertebrate-arthropod grouping). Because numerous additional genome and EST projects have been completed since 2005, it is now possible to test the results of Philip et al using improved taxon sampling. Here, homologues of those five protein-coding genes (prefoldin 2, Tim22, U6 snRNP-associated protein, MAK16, and autophagocytosis protein) were obtained from sequence databases for additional taxa. Phylogenetic analyses of concatenation of those genes, using improved taxon sampling, recovered monophyly of Opisthokonta and Ecdysozoa, as well as Protostomia and Lophotrochozoa. These results again illustrate the importance of increased taxon sampling as shown in numerous previous studies using other datasets.
Sulfur-bound biomarkers of a Monterey shale and a Greenland lake sediment
Authors: Stern Joshua
Published: June 2009

Seeking to reconstruct the biogeochemical processes that produced organic sulfur compounds in two unique depositional environments, we used the nickel boride desulfurization reaction to release hydrocarbons from sulfur-bound macromolecules not otherwise amenable to chromatographic analysis. We desulfurized two geochemical extracts: one sample is a Monterey shale of late Miocene age, and the other sample is a surface sediment from the Greenland lake Brayasø. Both samples contained organic sulfur compounds, but the Monterey shale was biologically and thermally modified after deposition. A comparison of the free and sulfur-bound hydrocarbons from each sample revealed a precursor-product relationship between tocopherol and pristane, for Monterey. Greenland’s composition may indicate that photochemical sulfurization occurs in the Brayasø oxic zone. We found that sulfurization may proceed at different rates for different compound families; for example, we did not see any sulfurized alkenones in Brayasø, but we found an abundance of sulfurized isoprenoids. Greenland’s relatively high overall desulfurization yield suggests that sulfurization in Brayasø occurs in under 40 years. Our Greenland findings suggest that photochemical sulfurization may be more widespread than previously thought, and that sulfurization might not interfere with alkenone paleotemperature reconstructions.
Oxygen: a master regulator of pancreatic development?
Authors: Fraker Christopher A. , Ricordi Camillo , Inverardi Luca , Domínguez‐Bendala Juan
Published: June 2009

Beyond its role as an electron acceptor in aerobic respiration, oxygen is also a key effector of many developmental events. The oxygen‐sensing machinery and the very fabric of cell identity and function have been shown to be deeply intertwined. Here we take a first look at how oxygen might lie at the crossroads of at least two of the major molecular pathways that shape pancreatic development. Based on recent evidence and a thorough review of the literature, we present a theoretical model whereby evolving oxygen tensions might choreograph to a large extent the sequence of molecular events resulting in the development of the organ. In particular, we propose that lower oxygenation prior to the expansion of the vasculature may favour HIF (hypoxia inducible factor)‐mediated activation of Notch and repression of Wnt/β‐catenin signalling, limiting endocrine cell differentiation. With the development of vasculature and improved oxygen delivery to the developing organ, HIF‐mediated support for Notch signalling may decline while the β‐catenin‐directed Wnt signalling is favoured, which would support endocrine cell differentiation and perhaps exocrine cell proliferation/differentiation.
8-Bromo-cyclic inosine diphosphoribose: towards a selective cyclic ADP-ribose agonist
Authors: Kirchberger Tanja , Moreau Christelle , Wagner Gerd K. , Fliegert Ralf , Siebrands Cornelia C. , Nebel Merle , Schmid Frederike , Harneit Angelika , Odoardi Francesca , Flügel Alexander , Potter Barry V. L. , Guse Andreas H.
Published: June 2009

cADPR (cyclic ADP-ribose) is a universal Ca2+ mobilizing second messenger. In T-cells cADPR is involved in sustained Ca2+ release and also in Ca2+ entry. Potential mechanisms for the latter include either capacitative Ca2+ entry, secondary to store depletion by cADPR, or direct activation of the non-selective cation channel TRPM2 (transient receptor potential cation channel, subfamily melastatin, member 2). Here we characterize the molecular target of the newly-described membrane-permeant cADPR agonist 8-Br-N1-cIDPR (8-bromo-cyclic IDP-ribose). 8-Br-N1-cIDPR evoked Ca2+ signalling in the human T-lymphoma cell line Jurkat and in primary rat T-lymphocytes. Ca2+ signalling induced by 8-Br-N1-cIDPR consisted of Ca2+ release and Ca2+ entry. Whereas Ca2+ release was sensitive to both the RyR (ryanodine receptor) blocker RuRed (Ruthenium Red) and the cADPR antagonist 8-Br-cADPR (8-bromo-cyclic ADP-ribose), Ca2+ entry was inhibited by the Ca2+ entry blockers Gd3+ (gadolinium ion) and SKF-96365, as well as by 8-Br-cADPR. To unravel a potential role for TRPM2 in sustained Ca2+ entry evoked by 8-Br-N1-cIDPR, TRPM2 was overexpressed in HEK (human embryonic kidney)-293 cells. However, though activation by H2O2 was enhanced dramatically in those cells, Ca2+ signalling induced by 8-Br-N1-cIDPR was almost unaffected. Similarly, direct analysis of TRPM2 currents did not reveal activation or co-activation of TRPM2 by 8-Br-N1-cIDPR. In summary, the sensitivity to the Ca2+ entry blockers Gd3+ and SKF-96365 is in favour of the concept of capacitative Ca2+ entry, secondary to store depletion by 8-Br-N1-cIDPR. Taken together, 8-Br-N1-cIDPR appears to be the first cADPR agonist affecting Ca2+ release and secondary Ca2+ entry, but without effect on TRPM2.
Proteomics identification and annotation of proteins of a cell line of Bombyx mori, BmN cells
Authors: Yao Hui-peng , Chen Lin , Xiang Xingwei , Guo Ai-qin , Lu Xing-meng , Wu Xiao-feng
Published: June 2009

A cell line is an important experimental platform for biological sciences as it can basically reflect the biology of its original organism. In this study, we firstly characterized the proteome of cultured BmN cells, derived from Bombyx mori. Total 1478 proteins were identified with two or more peptides by using 1D (one-dimensional) SDS/PAGE and LTQ-Orbitrap. According to the gene ontology annotation, these proteins presented diverse pI values and molecular masses, involved in various molecular functions, including catalytic activity, binding, molecular transducer activity, motor activity, transcription regulator activity, enzyme regulator activity and antioxidant activity. Some proteins related to virus infection were also identified. These results provided us with useful information to understand the molecular mechanism of B. mori as well as antiviral immunity.
The proper treatment of language acquisition and change in a population setting
Authors: Niyogi Partha , Berwick Robert C.
Published: June 2009

Language acquisition maps linguistic experience, primary linguistic data (PLD), onto linguistic knowledge, a grammar. Classically, computational models of language acquisition assume a single target grammar and one PLD source, the central question being whether the target grammar can be acquired from the PLD. However, real-world learners confront populations with variation, i.e., multiple target grammars and PLDs. Removing this idealization has inspired a new class of population-based language acquisition models. This paper contrasts 2 such models. In the first, iterated learning (IL), each learner receives PLD from one target grammar but different learners can have different targets. In the second, social learning (SL), each learner receives PLD from possibly multiple targets, e.g., from 2 parents. We demonstrate that these 2 models have radically different evolutionary consequences. The IL model is dynamically deficient in 2 key respects. First, the IL model admits only linear dynamics and so cannot describe phase transitions, attested rapid changes in languages over time. Second, the IL model cannot properly describe the stability of languages over time. In contrast, the SL model leads to nonlinear dynamics, bifurcations, and possibly multiple equilibria and so suffices to model both the case of stable language populations, mixtures of more than 1 language, as well as rapid language change. The 2 models also make distinct, empirically testable predictions about language change. Using historical data, we show that the SL model more faithfully replicates the dynamics of the evolution of Middle English.
Extreme inbreeding in
Leishmania braziliensis
Authors: Rougeron Virginie , De Meeûs Thierry , Hide Mallorie , Waleckx Etienne , Bermudez Herman , Arevalo Jorge , Llanos-Cuentas Alejandro , Dujardin Jean-Claude , De Doncker Simone , Le Ray Dominique , Ayala Francisco J. , Bañuls Anne-Laure
Published: June 2009

Leishmania
species of the subgenus
Viannia
and especially
Leishmania braziliensis
are responsible for a large proportion of New World leishmaniasis cases. The reproductive mode of
Leishmania
species has often been assumed to be predominantly clonal, but remains unsettled. We have investigated the genetic polymorphism at 12 microsatellite loci on 124 human strains of
Leishmania braziliensis
from 2 countries, Peru and Bolivia. There is substantial genetic diversity, with an average of 12.4 ± 4.4 alleles per locus. There is linkage disequilibrium at a genome-wide scale, as well as a substantial heterozygote deficit (more than 50% the expected value from Hardy−Weinberg equilibrium), which indicates high levels of inbreeding. These observations are inconsistent with a strictly clonal model of reproduction, which implies excess heterozygosity. Moreover, there is large genetic heterogeneity between populations within countries (Wahlund effect), which evinces a strong population structure at a microgeographic scale. Our findings are compatible with the existence of population foci at a microgeographic scale, where clonality alternates with sexuality of an endogamic nature, with possible occasional recombination events between individuals of different genotypes. These findings provide key clues on the ecology and transmission patterns of
Leishmania
parasites.
ABACAS: algorithm-based automatic contiguation of assembled sequences
Authors: Assefa Samuel , Keane Thomas M. , Otto Thomas D. , Newbold Chris , Berriman Matthew
Published: June 2009

Summary: Due to the availability of new sequencing technologies, we are now increasingly interested in sequencing closely related strains of existing finished genomes. Recently a number of de novo and mapping-based assemblers have been developed to produce high quality draft genomes from new sequencing technology reads. New tools are necessary to take contigs from a draft assembly through to a fully contiguated genome sequence. ABACAS is intended as a tool to rapidly contiguate (align, order, orientate), visualize and design primers to close gaps on shotgun assembled contigs based on a reference sequence. The input to ABACAS is a set of contigs which will be aligned to the reference genome, ordered and orientated, visualized in the ACT comparative browser, and optimal primer sequences are automatically generated.

Availability and Implementation: ABACAS is implemented in Perl and is freely available for download from http://abacas.sourceforge.net

Contact:  sa4@sanger.ac.uk
Improved rhizosphere competence in a protoplast fusion progeny of Trichoderma harzianum
Authors: Sivan A. , Harman G. E.
Published: June 2009

The level and pattern of rhizosphere competence of a strain of Trichoderma harzianum (1295-22) derived from fusing protoplasts of auxotrophic mutants of the prototrophic strains T12 and T95 were studied and compared with those of the original strains. Colonization of the rhizosphere by the three strains was tested after treating seeds of cotton and maize with conidia and planting them in soil at a constant moisture content. Propagules of the fungi were removed by a washing technique, Trichoderma spp. were isolated by plating serial dilutions on a selective medium, and individual strains were identified by their characteristic growth on differential media. Both strains T12 and T95 colonized the entire length of maize roots, but strain 1295-22 was more effective in colonizing the middle sections of the roots than either parental strain. All strains colonized cotton roots more poorly than maize roots; strains T12 and T95 were not detected on some root segments of this crop. Strain T95 was, however, found on the root tip, while T12 was absent from this root portion. Conversely, strain 1295-22 colonized all root sections of this crop, and its population levels were higher in the middle root portions than those of either parental strain.
Helicobacter pylori catalase
Authors: Hazell Stuart L. , Evans Doyle J. , Graham David Y.
Published: June 2009

Summary:Helicobacter pyloriis the major aetiological agent of gastroduodenitis in humans. Due to the potential importance of catalase in the growth and survival ofHelicobacter pylorion the surface of inflamed mucosae, we have characterized catalase fromH. pylorias a prelude to further studies on the function of the enzymein vivo. The catalase activity ofH. pyloriwas significantly affected by the presence of blood, serum or erythrocytes in the growth medium: the greatest activity was expressed when the bacterium was grown on medium containing serum.H. pyloricatalase is a tetramer with a subunitMrof 50000. The enzyme had a pI of 9·0–9·3, was active over a broad pH range and was stable at 56 °C. It was non-competitively inhibited by sodium azide, and had no detectable peroxidase activity. TheKmfor the purified catalase was measured as 43 · 3 mm-H2O2and theVas 60 ± 3 mmol H2O2min-1(mg protein)-1. The native catalase has absorption maxima at 280 nm and 405 nm with further minor shoulders or peaks at 510 nm, 535 nm and 625 nm, consistent with the presence of an iron-porphyrin prosthetic group.
Cytolysis of Bacillus subtilis by Fusarium oxysporum
Authors: Grant W. D. , Prosser B. A. , Wakefield St J.
Published: June 2009

Growth of Fusarium oxysporum on heat-killed Bacillus subtilis cells was accompanied by the loss of bacterial cytoplasmic contents, and this ‘cytolysis’ could be catalysed in heat-treated bacteria by the fungal culture fluids. In electron micrographs the bacterial walls appeared undamaged, and the absence of wall-lytic enzymes was confirmed by use of isolated bacterial walls as substrate. Appearance of cytolytic activity in cultures was paralleled by the production of proteolytic activity in the cultures. Proteolysis and cytolysis had similar pH optima at 8·8–9·0. Cultures grown on casein, but not glucose, produced high cytolytic activity. Rapid cytolysis occurred when heat-treated B. subtilis cells were incubated with trypsin, subtilisin or pronase E. Viable bacteria, however, were not attacked, either by concentrated culture fluids or by the commercial protease preparations.
The cytochrome bd quinol oxidase in Escherichia coli has an extremely high oxygen affinity and two oxygen-binding haems: implications for regulation of activity in vivo by oxygen inhibition
Authors: D'mello Rita , Hill Susan , Poole Robert K.
Published: June 2009

Cytochrome bd is a respiratory oxidase in
Escherichia coli
and many other bacteria. It contains cytochromes b
558′
b
595 and d as redox centres, and is thus unrelated to the haem-copper super-family of terminal oxidases. The apparent affinities (K
m) for oxygen uptake by respiring cells and membranes from a mutant lacking the alternative oxidase cytochrome bo’ were determined by deoxygenation of oxyleghaemoglobin as a sensitive reporter of dissolved oxygen concentration. Respiration rates were maximal at oxygen concentrations of 25-50 nM, but the kinetics were complex and indicative of substrate (i.e. oxygen) inhibition. K
m values were in the range 3-8 nM (the lowest recorded for a respiratory oxidase), and K
l values between 0.5 and 1.8 μM were obtained. Low temperature photodissociation of anoxic, CO-ligated membranes confirmed the absence of cytochrome bo’ and revealed a high-spin b-type cytochrome identified as cytochrome b
595 of the cytochrome bd complex. Photodissociation in the presence of oxygen revealed binding of a ligand (presumably oxygen) to cytochrome b
595 at a rate much greater than that of CO binding, and formation of the oxygenated form of cytochrome d. The results confirm that both high-spin haems in the cytochrome bd complex bind CO and demonstrate that oxygen can also react with both haems. Substrate inhibition of oxidase activity, in addition to transcriptional regulation of oxidase synthesis, may play a crucial role in the regulation of partitioning of electron flux between the cytochrome bd- and bo’-terminated respiratory pathways.
Analysis of the EHEC hly operon and its location in the physical map of the large plasmid of enterohaemorrhagic Escherichia coli O157:H7
Authors: Schmidt Herbert , Kernbach Christian , Karch Helge
Published: June 2009

Almost all clinical enterohaemorrhagic
Escherichia coli
(EHEC) O157: H7 isolates harbour a large virulence plasmid designated pO157. In this study, pO157 of EHEC O157:H7 reference strain EDL 933 was characterized at the molecular level. A restriction map was constructed by using seven restriction enzymes, with appropriate gel electrophoretic and hybridization methods. The molecular size of pO157 was determined to be 93.6 kb. By sequencing the DNA region extending in the 3′-direction of the previously described EHEC hlyC and hlyA genes, two further genes were discovered and analysed; these were termed EHEC hlyB and EHEC hlyD. The newly discovered genes together with the EHEC hlyC and hlyA genes constitute a typical RTX (Repeats in ToXin) determinant (EHEC hly operon) with the gene order CABD. The map position of the operon was determined by hybridization experiments. Analysis of a DNA fragment carrying the downstream flanking region of the EHEC hly operon revealed an open reading frame which was highly homologous to orf1 of RepFIB, a basic replicon of IncF plasmids. It was located close to the EHEC hly operon.
The outermost capsular arabinomannans and other mannoconjugates of virulent and avirulent tubercle bacilli
Authors: Ortalo-Magné Annick , Andersen Åse B. , Daffé Mamadou
Published: June 2009

It has been shown that phagocyte mannose receptors play an important role in phagocytosis of virulent tubercle bacilli, but not of avirulent strains. Accordingly, we investigated the occurrence and structure of the outermost mannoconjugates of the capsule of five strains of the tubercle bacillus differing in their degrees of virulence. The extracellular and surface-exposed arabinomannan-containing polysaccharides were chemically characterized as being composed mainly of neutral fatty-acyl-free arabinomannans (AMs) possessing a reducing end consisting of mannose. Although no lipoarabinomannan (LAM) was detected, small amounts of acidic polysaccharides, exhibiting the same electrophoretic mobility as LAM, were identified as succinylated AMs (two to three residues per molecule) lacking the phosphatidylinositol anchor of LAM. AMs from the different strains shared the same structural features, notably the capping of a large portion of the arabinan segments with mannosyl residues. However, no correlation was observed between either the percentage of capping or the amount of AMs and the degrees of virulence of the strains. The occurrence and amounts of other mannoconjugates (phosphatidylinositol mannosides and the mannoseassociated 19 and 38 kDa lipoproteins) in the various tubercle bacilli were also examined. Although both classes of compounds were identified in all the examined strains, a correlation between the amounts of the glycoconjugates and the degrees of virulence of the strains could not be established. These data do not support the implication of these promising mannosylated molecules in the selective phagocytosis of virulent tubercle bacilli and indicate that the involvement of mannose receptors in phagocytosis of virulentM. tuberculosisneeds to be re-investigated.
Bacteriophage receptors on Listeria monocytogenes cells are the N-acetylglucosamine and rhamnose substituents of teichoic acids or the peptidoglycan itself
Authors: Wendlinger Günther , Loessner Martin J. , Scherer Siegfried
Published: June 2009

Different approaches were used to examine the function of teichoic acids (TA) as phage receptors among selected Listeria strains, and to identify and characterize specific receptor structures of host cells belonging to different serovars. This included successive removal of cell wall constituents, preparation and purification of TA, and GLC analysis of TA components. Adsorption of Listeria monocytogenes bacteriophages could be inhibited by polyvalent antisera, specific lectins and addition of purified TA. The results confirmed the necessity of TA in general and of rhamnose and glucosamine in particular for adsorption of Listeria phage A118, which is a temperate Siphovirus (morphotype B1), attacking predominantly serovars 1/2. Host binding of siphoviral phage A500 (predominantly lysing serovars 4b), was also dependent on cell wall TA. A phage-resistant L. monocytogenes strain was shown to lack glucosamine in its TA. These results support the view that TA substituents may play an important role not only in antigenicity of Listeria cells, but also in specificity of host recognition by two temperate Listeria phages. In contrast, the broad-host-range virulent phage A511 (Myovirus, morphotype A1) uses the listerial peptidoglycan as primary receptor. This corresponds well with the observation that A511 is capable of lysing the majority of L. monocytogenes strains.
Use of Siderophores to Type Pseudomonads: The Three Pseudomonas Aeruginosa Pyoverdine Systems
Authors: Meyer Jean-Marie , Stintzi Alain , De Vos Daniel , Cornelis Pierre , Tappe Robert , Taraz Kambiz , Budzikiewicz Herbert
Published: June 2009

Eighty-eight Pseudomonas aeruginosa isolates, most of them from the Collection of Bacterial Strains of the Institut Pasteur, Paris, were analysed for their pyoverdine-mediated iron incorporation system by different methods, including pyoverdine isoelectrofocusing analysis, pyoverdine-mediated growth stimulation, immunoblot detection of (ferri)pyoverdine outer-membrane receptor and pyoverdine-facilitated iron uptake. The same grouping of the strains was reached by each of these methods, resulting in the classification of the P. aeruginosa isolates, even those which were devoid of pyoverdine production, into three different siderophore types. Forty-two percent of the strains were identified with the type-strain P. aeruginosa ATCC 15692 (group I). 42% were identical with the second type-strain P. aeruginosa ATCC 27853 (group II) and 16% reacted identically with the clinical isolate P. aeruginosa Pa6, whose pyoverdine was recognized in this study to be identical in structure to the pyoverdine produced by a natural isolate, P. aeruginosa strain R. No new pyoverdine species was detected among these strains.
TNF-a, IL-1a, IL-6 and ICAM-1 Expression in Human Keratinocytes Stimulated in Vitro with Escherichia Coli Heat-Shock Proteins
Authors: Marcatili Antonella , de I'Ero Gabriella Cipollaro , Galdiero Marilena , Folgore Antonio , Petrillo Giulio
Published: June 2009

Bacterial heat-shock proteins (HSPs) fromEscherichia coli(GroES, GroEL and DnaK) were studied for their ability to induce by themselves the expression and release of tumour necrosis factor-a (TNF-a), interleukin-6 (IL-1a), interleukin-6 (IL-6) and intercellular adhesion molecule-1 (ICAM-1) by cultured human keratinocytes. The surface expression of ICAM-1 was also investigated. In the supernatants of untreated cells none or a minimal amount of these molecules was found. After 48 h of stimulation with GroEL significant amounts of TNF-a, IL-1a, IL-6 and soluble ICAM-1 were detected, reaching maximum concentrations at 1 g ml-1. The same effect was elicited by DnaK but to a lesser extent. Treatment of keratinocytes with GroEL and DnaK also increased TNF-a, IL-1a, IL-6 and ICAM-1 mRNA levels. GroES showed significant activity only on the expression and release of IL-6. GroEL and DnaK were also able to up-regulate the surface expression of ICAM-1 on keratinocytes. The effects on ICAM-1 expression seemed to be directly due to HSPs and not mediated via cytokines. Furthermore, these effects were due to the properties of HSPs because they were inhibited by specific monoclonal antibodies. These findings support the potential role of HSPs in modulating cell interactions during immunological and inflammatory responses in the skin.
Structural analysis of the 6 kb cryptic plasmid pFAJ2600 from Rhodococcus erythropolis NI86/21 and construction of Escherichia coli-Rhodococcus shuttle vectors
Authors: De Mot René , Nagy István , De Schrijver Adinda , Pattanapipitpaisal Pranee , Schoofs Geert , Vanderleyden Jos
Published: June 2009

The complete nucleotide sequence of the 5936 bp cryptic plasmid pFAJ2600 from Rhodococcus erythropolis NI86/21 was determined. Based on the characteristics of its putative replication genes, repA and repB, pFAJ2600 was assigned to the family of pAL5000-related small replicons identified in Mycobacterium (pAL5000), Corynebacterium (pXZ10142), Brevibacterium (pRBL1), Bifidobacterium (pMB1) and Neisseria (pJD1). The replication systems of these plasmids show striking similarities to the ones used by the ColE2 family of plasmids from Enterobacteria with respect to both trans-acting factors and ori sequences. Two possible plasmid stabilization systems are encoded on pFAJ2600: a site-specific recombinase (PmrA) related to the Escherichia coli Xer proteins for plasmid multimer resolution and an ATPase (ParA) related to the A-type of proteins in sop/par partitioning systems. The proposed replication termination region of pFAJ2600 has features in common with the Ter loci of Bacillus subtilis. Chimeras composed of a pUC18-Cmr derivative inserted in the parA-repA intergenic region of vector pFAJ2600 produced vectors that could be shuttled between Escherichia coli and several Rhodococcus species (R. erythropolis, R. fascians, R. rhodochrous, R. ruber). The pFAJ2600-based shuttle vector pFAJ2574 was stably maintained in R. erythropolis and R. fascians growing under non-selective conditions.
Functional and genetic characterization of mcpC, which encodes a third methyl-accepting chemotaxis protein in Bacillus subtilis
Authors: Müller Jakob , Schiel Stacey , Ordal George W. , Saxild Hans H.
Published: June 2009

A 3135 bp DNA segment downstream of the spl gene on the Bacillus subtilis chromosome was cloned and its nucleotide sequence determined. An open reading frame capable of encoding a putative protein of 654 amino acids with a calculated molecular mass of 72.1 kDa was identified. The deduced amino acid sequence was similar to the McpA and McpB proteins of B. subtilis. McpA and McpB encode different methyl-accepting chemotaxis proteins (MCPs). A mutant strain containing an antibiotic resistance DNA cassette inserted into the region containing the MCP-like reading frame suffered a complete loss of taxis to the amino acids cysteine, proline, threonine, glycine, serine, lysine, valine and arginine. The open reading frame was designated mcpC. The wild-type and an mcpC mutant strain were analysed for their content of methylated proteins and it was found that mcpC encodes a methylated membrane protein that has previously been designated H3. These results show that mcpC encodes a third MCP in B. subtilis. The transcription start site upstream of the mcpC gene was determined by primer extension analysis and it was found to be preceded by a potential promoter sequence that is recognized by the β
D
form of RNA polymerase. The level of β-gaiactosidase expressed from a transcriptional mcpC-lacZ fusion was increased threefold when cells entered the stationary phase. No β-gaiactosidase could be detected in a sigD genetic background.
Sequencing and mutagenesis of genes from the erythromycin biosynthetic gene cluster of Saccharopolyspora erythraea that are involved in L-mycarose and D-desosamine production
Authors: Summers Richard G. , Donadio Stefano , Staver Michael J. , Wendt-Pienkowski Evelyn , Hutchinson C. Richard , Katz Leonard
Published: June 2009

The nucleotide sequence on both sides of the eryA polyketide synthase gene of the erythromycin-producing bacterium Saccharopolyspora erythraea reve the presence of ten genes that are involved in L-mycarose (eryB) and D-desosamine (eryC) biosynthesis or attachment. Mutant strains carrying targeted lesions in eight of these genes indicate that three (eryBIV, eryBV an eryBVI) act in L-mycairose biosynthesis or attachment, while the other five (eryCII, eryCIII, eryCIV, eryCV and eryCVI) are devoted to D-desosamine biosynthesis or attachment. The remaining two genes (eryBII and eryBVII) appear to function in L-mycarose biosynthesis based on computer analysis an earlier genetic data. Three of these genes, eryBII, eryCIII and eryCII, lie between the eryAIII and eryG genes on one side of the polyketide synthase genes, while the remaining seven, eryBIV, eryBV, eryCVI, eryBVI, eryCIV, eryC and eryBVII lie upstream of the eryAI gene on the other side of the gene cluster. The deduced products of these genes show similarities to: aldohexos 4-ketoreductases (eryBIV), aldoketo reductases (eryBII), aldohexose 5-epimerases (eryBVII), the dnmT gene of the daunomycin biosynthetic pathwa of Streptomyces peucetius (eryBVI), glycosyltransferases (eryBV and eryCIII), the AscC 3,4-dehydratase from the ascarylose biosynthetic pathway of Yersin pseudotuberculosis (eryCIV), and mammalian N-methyltransferases (eryCVI). The eryCII gene resembles a cytochrome P450, but lacks the conserved cysteir residue responsible for coordination of the haem iron, while the eryCV gene displays no meaningful similarity to other known sequences. From the predicted function of these and other known eryB and eryC genes, pathways for the biosynthesis of L-mycarose and D-desosamine have been deduced.
Production of putative virulence factors by Renibacterium salmoninarum grown in cell culture
Authors: Mcintosh D. , Flaño E. , Grayson T. H. , Gilpin M. L. , Austin B. , Villena A. J.
Published: June 2009

A cell culture system, employing the fish cell line Epithelioma papillosum cyprini (EPC), was developed to study the synthesis of intracellular antigen and the expression of putative virulence factors by Renibacterium salmoninarum. EPC cultures infected with R. salmoninarum could be maintained for 7 weeks, during which the pathogen multiplied intracellularly. Immunohistochemical examination of infected cultures revealed the production of the p57 antigen, haemolysin and cytolysin. The intracellular nature of the infection was confirmed by transmission electron microscopic examination of EPC monolayers. A comparison of the relative virulence of bacterial cells cultured in EPC cells and on agar plates revealed that the former were markedly more virulent in challenge experiments with juvenile rainbow trout (Oncorhynchus mykiss Walbaum). The EPC cell culture model provided a system for the study of R. salmoninarum under more natural conditions than those achieved with plate culture techniques.
A 12-cistron Escherichia coli operon (hyf) encoding a putative proton-translocating formate hydrogenlyase system
Authors: Andrews Simon C. , Berks Ben C. , McClay Joseph , Ambler Andrew , Quail Michael A. , Golby Paul , Guest John R.
Published: June 2009

The nucleotide sequence has been determined for a twelve-gene operon ofEscherichia colidesignated thehyfoperon (hyfABCDEFGHIR-focB). Thehyfoperon is located at 55.8-56.0 min and encodes a putative nine-subunit hydrogenase complex (hydrogenase four or Hyf), a potential formate- and σ54dependent transcriptional activator, HyfR (related to FhlA), and a possible formate transporter, FocB (related to FocA). Five of the nine Hyf-complex subunits are related to subunits of both theE. colihydrogenase-3 complex (Hyc) and the proton-translocating NADH:quinone oxidoreductases (complex I and Nuo), whereas two Hyf subunits are related solely to NADH:quinone oxidoreductase subunits. The Hyf components include a predicted 523 residue [Ni-Fe] hydrogenase (large subunit) with an N-terminus (residues 1-170) homologous to the 30 kDa or NuoC subunit of complex I. It is proposed that Hyf, in conjunction with formate dehydrogenase H (Fdh-H), forms a hitherto unrecognized respiration-linked proton-translocating formate hydrogenlyase (FHL-2). It is likely that HyfR acts as a formate-dependent regulator of thehyfoperon and that FocB provides the Hyf complex with external formate as substrate.
Functional redundancy of genes for sulphate activation enzymes in Rhizobium sp. BR816
Authors: Laeremans T. , Coolsaet N. , Verreth C. , Snoeck C. , Hellings N. , Vanderleyden J. , Martínez-Romero E.
Published: June 2009

The broad-host-range, heat-tolerant Rhizobium strain BR816 produces sulphated Nod metabolites. Two ORFs highly homologous to the Sinorhizobium meliloti nodPQ genes were isolated and sequenced. It was found that Rhizobium sp. BR816 contained two copies of these genes; one copy was localized on the symbiotic plasmid, the other on the megaplasmid. Both nodP genes were interrupted by insertion of antibiotic resistance cassettes, thus constructing a double nodP1P2 mutant strain. However, no detectable differences in Nod factor TILC profile from this mutant were observed as compared to the wild-type strain. Additionally, plant inoculation experiments did not reveal differences between the mutant strain and the wild-type. It is proposed that a third, functionally homologous locus complements mutations in the Nod factor sulphation genes. Southern blot analysis suggested that this locus contains genes necessary for the sulphation of amino acids.
Identification of salivary basic proline-rich proteins as receptors for Candida albicans adhesion
Authors: O'Sullivan Justin M. , Cannon Richard D. , Sullivan Patrick A. , Jenkinson Howard F.
Published: June 2009

The adherence of Candida albicans cells to oral surfaces is believed to be an important step in the development of oral candidosis. Electrophoretically separated parotid salivary proteins were transferred to nitrocellulose membranes and incubated with [35S]methionine-radiolabelled C. albicans cells in a cell overlay adherence assay. A subset of four proteins with apparent molecular masses of 17, 20, 24 and 27 kDa (designated bands A-D) acted as receptors for cells of C. albicans ATCC 10261 and four clinical C. albicans isolates, in overlay assays. The N-terminal amino acid sequence of bands A-D indicated that these proteins were members of the basic proline-rich protein (bPRP) family. Digestion of protein A with endoproteinase Glu-C resulted in a single band (designated Ap) detected by Coomassie blue staining after SDS-PAGE. This band was not bound by C. albicans cells in overlay assays and comprised two fragments, designated ApN and ApC. These fragments had N-terminal sequences corresponding to the N-terminal and post endoproteinase Glu-C cleavage site sequences of bPRP IB-6 and had molecular masses of 618S and 4261 Da as determined by mass spectrometry. Thus intact bPRP IB-6, and other bPRPs, may act as receptors for C. albicans adhesion.
The topoisomerase I gene from Candida albicans
Authors: Jiang Weidong , Gerhold David , Kmiec Eric B. , Hauser Melinda , Becker Jeffrey M. , Koltin Yigal
Published: June 2009

We report here the cloning of the Candida albicans genomic topoisomerase I gene (TOP1) by use of PCR and subsequent hybridization. The predicted protein sequence shared 58.8% identity with the Saccharomyces cerevisiae topoisomerase I and 30-50% identity with other eukaryotic topoisomerase I proteins. A conditional gene disruption strain (CWJ477) was constructed so that one copy of TOP1 was deleted and the other copy of TOP1 was placed under a regulatable promoter. Under repressed conditions, cells grew slowly and cell morphology was abnormal. The virulence of CWJ477 was markedly reduced in a mouse model system, and that of the single gene knockout strain was slightly attenuated, indicating that TOP1 might play a role in the infection of C. albicans in mice in a dose-dependent manner. Despite the reduced virulence of both the single and double knockout strains, viable cells of the pathogen were recovered from the kidneys as late as 22 d post-infection.
An oligopeptide transport gene from Candida albicans
Authors: Lubkowitz Mark A. , Hauser Loren , Breslav Michael , Naider Fred , Becker Jeffrey M.
Published: June 2009

A Candida albicans oligopeptide transport gene, OPT1, was cloned from a C. albicans genomic library through heterologous expression in the Saccharomyces cerevisiae di-/tripeptide transport mutant PB1X-9B. When transformed with a plasmid harbouring OPT1, S. cerevisiae PB1X-9B, which did not express tetra-/pentapeptide transport activity under the conditions used, was conferred with an oligopeptide transport phenotype, as indicated by growth on the tetrapeptide Lys-Leu-Leu-Gly, sensitivity to toxic tetra- and pentapeptides, and an increase in the initial uptake rate of the radiolabeled tetrapeptide Lys-Leu-Gly-[3H]Leu. The level of oligopeptide transport was found to be influenced in the heterologous host by the source of nitrogen used for growth. The entire 3.8 kb fragment containing the oligopeptide transport activity was sequenced and an ORF of 2349 nucleotides containing a 58 nucleotide intron was identified. The deduced protein product of 783 amino acid residues contained 12 hydrophobic regions suggestive of a membrane transport protein. Sequence comparisons revealed that similar proteins are encoded by genes from S. cerevisiae and Schizosaccharomyces pombe and that OPT1 is not a member of the ABC or PTR membrane transport families.
Investigation of space flight effects on Escherichia coli and a proposed model of underlying physical mechanisms
Authors: Klaus David , Simske Steven , Todd Paul , Stodieck Louis
Published: June 2009

Previous investigations have reported that space flight may produce a stimulating effect on microbial metabolism; however, the specific underlying mechanisms associated with the observed changes have not yet been identified. In an effort to systematically evaluate the effect of space flight on each phase of microbial growth (lag, exponential and stationary), a series of experiments was carried out using in vitro suspension cultures of Escherichia coli aboard seven US Space Shuttle missions. The results indicated that, as a result of space flight, the lag phase was shortened, the duration of exponential growth was increased, and the final cell population density was approximately doubled. A model was derived from these cumulative data in an attempt to associate gravity-dependent, extracellular transport phenomena with unique changes observed in each specific phase of growth. It is suggested that a cumulative effect of gravity may have a significant impact on suspended cells via their fluid environment, where an immediate, direct influence of gravity might otherwise be deemed negligible.