bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvements in appetite and growth in helminth-infected schoolboys three and seven weeks after a single dose of pyrantel pamoate
Authors: Hadju V. , Stephenson L. S. , Abadi K. , Mohammed H. O. , Bowman D. D. , Parker R. S.
Published: June 2009

Appetite and growth were studied in primary schoolboys (6–10 years) infected withAscaris lumbricoides(86%) andTrichuris trichiura(100%) who received a single dose of pyrantel pamoate (which has little or no effect onTrichuris trichiura) or a placebo. Boys were examined, allocated at random by descendingAscarisegg count to pyrantel (PR,n= 36) or placebo (PL,n= 36) groups, treated, and re-examined 3 and 7 weeks later. The 2 groups did not differ significantly before treatment in helminth infections, appetite, or growth. Three and 7 weeks after treatment, the PR group exhibited significantly greater increases than did the PL group in weight (0·2 kg and 0·4 kg more, respectively) and percentage weight-for-age (0·6% and 1·7% points more, respectively). Appetite increased significantly in the PR group at 3 and 7 weeks (P< 0·0005 andP< 0·01, respectively) but not in the PL group. The prevalence and intensity ofA. lumbricoidesinfection were greatly reduced in the PR group at 3 and 7 weeks (bothP< 0·0001) but not in the PL group. We conclude that treatment with pyrantel pamoate may improve appetite and growth in schoolchildren in areas whereA. lumbricoidesinfections and poor growth are highly prevalent.
The epidemiology of canine visceral leishmaniasis in southern France: classical theory offers another explanation of the data
Authors: Dye Christopher
Published: June 2009

This paper describes a compartmental model incorporating biological details of the transmission of canine visceral leishmaniasis in southern France. In contrast to earlier, empirical models (Jolivet, 1977; Rioux, Croset & Lanotte, 1977) the new model (1) predicts a threshold density of sandflies below which transmission cannot be sustained, (2) suggests that, until better data become available, the maximum prevalence of infection obtained at high sandfly density should be considered an unknown quantity.
Changes in the organization of the surface membrane upon transformation of cercariae to schistosomula of the helminth parasite Schistosoma mansoni
Authors: Foley M. , Kusel J. R. , Garland P. B.
Published: June 2009

Merocyanin 540 (Mc540) is a fluorescent compound which is thought to bind to membranes in which there are substantial amounts of lipid in the lipid-crystalline phase. It is shown here to be of value in detecting the transformation by both mechanical and skin-penetration methods of the cercaria to the schistosomulum. The cercaria does not appear to bind Mc540, but the schistosomulum, binds Mc540 initially, in its anterior region, and at later times over the entire surface. The suggestion that transformation involves changes in the surface membrane lipid phase from gel to liquid-crystalline phase is supported by fluorescence recovery after photobleaching results with 5-N-(octadecanoyl)-amino fluorescein, a lipophilic dye which appears to be immobile in the cercaria, but fully mobile in the 40 min schistosomulum.
Effect of temperature on survival and infectivity of Echinostoma trivolvis cercariae: a test of the energy limitation hypothesis
Authors: Pechenik J. A. , Fried B.
Published: June 2009

Trematode cercariae typically become unable to successfully infect a host many hours before they die. We examined the hypothesis that both time to 50% mortality and time to loss of infective capacity are controlled to the same degree by rates of energy expenditure, by determining the relative effects of temperature on both parameters. Infective capacity was assessed by exposing Echinostoma trivolvis cercariae of different ages to a suitable second intermediate host (the gastropod Biomphalaria glabrata) and counting 1–2 days later the number of metacercarial cysts formed. Temperature had a remarkably similar effect on time to 50% mortality and loss of infective capacity, supporting the hypothesis that both absolute and functional cercarial life-spans are limited by the rates at which energy stores are utilized.
Comparison of the transmission of Theileria parva between different instars of Rhipicephalus appendiculatus
Authors: Ochanda H. , Young A. S. , Wells C. , Medley G. F. , Perry B. D.
Published: June 2009

The transmission of Theileria parva by nymphal and adult Rhipicephalus appendiculatus was compared by the assessment of salivary gland infections in tick batches fed on the same group of infected cattle at the same time. When larval and nymphal R. appendiculatus Muguga ticks were fed concurrently on cattle undergoing acute infection with T. parva Muguga, the resultant nymphae developed a slightly lower prevalence of infection than did the adult ticks. The abundance of infection was 5–20 times higher in the adult ticks than in the nymphae. When larval and nymphal R. appendiculatus Muguga and R. appendiculatus McIlwaine were fed to repletion on cattle infected with T. parva Boleni, a parasite causing subacute infection, resultant adult tick batches had a relatively high prevalence of infection, but infection was not detected in resultant nymphal batches. When cattle that were carriers of 2 stocks of T. parva, Marikebuni and Kiambu 5, were used as the source of infection, the infections developing in adult R. appendiculatus Muguga ticks were much higher than those developing in nymphae. The structure of salivary glands differed between nymphal ticks, adult males and adult females, and this is considered to be an important factor affecting the infection levels. The morphology of the type III acini, the target acini for sporogony, was similar, but the mean numbers of type III acini were different, with 87 in nymphae, 1346 in males and 1736 in females. This difference was correlated with the different infection levels produced in the various instars and sexes. While the process of sporogony in the different tick instars and sexes was similar, the rate of sporogony was fastest in feeding nymphae, taking on average 2–3 days, compared to 3–4 days in females and an irregular period in the males. These results are discussed in relation to the epidemiology of T. parva.
The effect of substrates and inhibitors on the rate of respiration of the infective larvae of Strongyloides ratti Sandground, 1925
Authors: Barrett J.
Published: June 2009

The infective larvae of S. ratti were non-feeding and none of a wide variety of possible substrates had any effect on the respiratory rate of intact worms. Sodium succinate increased the oxygen uptake of larval homogenates.

The cytochrome chain inhibitors, sodium cyanide, sodium azide and urethane all reversibly inhibited the respiration of the infective larvae. The inhibition caused by carbon monoxide was photo-reversible and 2,4-dinitrophenol inhibited respiration rather than stimulated it. Methylene blue increased the oxygen uptake of homogenates, but had no effect on the intact larva. Iodoacetamide and sodium arsenite irreversibly inhibited respiration, whilst sodium fluoride, sodium pyrophosphate and sodium malonate were without effect on the intact larvae.

This work was carried out during the tenure of a Medical Research Council Scholarship.
Metamorphosis of Miracidia into Cercariae of Schistosoma mansoni in vitro
Authors: Muftic M.
Published: June 2009

At present our knowledge of the host-parasite relationships of the Schistosomatidae and their snail intermediate hosts is meagre. Because this knowledge is necessary in the search for effective therapeutic and control measures it would be useful to find an in vitro procedure facilitating continuous progenesis of schistosomes without the use of a snail host.
The fine structure of the protonephridial system in the miracidium of Fasciola hepatica
Authors: Wilson R. A.
Published: June 2009

The fine structure of the flame cells, tubules and excretory pore of the miracidium of Fasciola hepatica are described. The tubules are formed from the flattened surfaces of cells rolled round and joined at their tips by a desmosome. Vesicles are present in the wall of the tubule, possibly indicating secretory activity. Clubshaped microvilli are present only in the terminal region near the excretory pore. Possible functions of the system are discussed.
Oogenesis in the hermaphroditic Digenea (Trematoda)
Authors: Gresson R. A. R.
Published: June 2009

During the present century oogenesis and maturation have been extensively studied in the Digenea. The earlier observations, however, were based on limited methods of histological and cytological techniques and were concerned principally with the general features of the germ-cells and with their chromosomes. Consequently, until recently, little information has emerged regarding the extra-nuclear components of oogonia and oocytes and the changes that these cells undergo during oogenesis. The earlier work on the Digenea is reviewed by Cable (1931), Anderson (1935), Rees (1939), and more recent research is cited in the present paper.
The distribution of lipids and glycogen in some female oxyuroids
Authors: Anya A. O.
Published: June 2009

1. The distribution of glycogen and lipids in three oxyuroids (Aspiculuris tetraptera, Enterobius vermicularis and Syphacia obvelata) is described and found to be similar to that in ascarids and other oxyuroids.

2. Evidence is presented for the presence of both polysaccharides (possibly glycogen) and lipids in the cuticle.

3. It is suggested that the chitinous layer of the egg-shell of A. tetraptera contains phospholipids in association with proteins.

4. The distribution of phospholipids is described and it is suggested that their role is mainly structural.

I am grateful to Dr P. Tate for advice and encouragement and to Dr D. L. Lee for much useful discussion and advice.
Preface: Positive interactions between anti-infection drugs and the immune response: an emerging paradigm
Authors: Doenhoff M. J. , Chappell L. H.
Published: June 2009

In the third and fourth decades of this century chemotherapy began to be established as one of the greatest success stories in medicine. Now unfortunately severe problems compromise the efficacy of drugs used to treat infectious diseases, two of the most serious handicaps being the rapidity with which target pathogens can develop drug-resistance and the slow rate at which replacement products are appearing on the market. Increased understanding of the ways in which existing drugs act may help both to prolong their usefulness and to generate novel therapeutic strategies.
On the taxonomic position of the genus Encephalitozoon Levaditi, Nicolau & Schoen, 1923 (Protozoa: Microsporidia)
Authors: Weiser Jaroslav
Published: June 2009

The structure of the spores of Encephalitozoon cuniculi Levaditi, Nicolau & Schoen, 1923, shows that it belongs to the Order Microsporidia Balbiani, 1882 and that the genus Encephalitozoon is a synonym for the older Nosema Nägeli, 1857. Therefore, the species of Microsporidia described from mammals are now: Nosema cuniculi (Levaditi, Nicolau & Schoen, 1923), Nosema rabiei (Manouelian & Viala, 1924) and Nosema chagasi (Torres, 1927). Another microsporidian in mammals is Thelohania apodemi (Doby, Jeannes & Rault, 1963).
The distribution and dynamics of ked populations, Melophagus ovinus Linn.
Authors: Macleod John
Published: June 2009

Observations have been made on the distribution of adult and pupal keds over the body of sheep and lambs, and the seasonal changes in density and distribution have been followed by a series of counts on the same sixteen sheep throughout a period of 13 months.

The method of assessing the adult population by counting the living keds was checked by killing and subsequently counting them, and is believed to give approximately correct results. Pupal estimations by the ‘live-count’ method gave results apparently 50 % below the actual values.

The ked population builds up rapidly during late winter and early spring to a maximum in April and early May. A decline begins in May, and by June the population has decreased very considerably. During summer the unshorn lambs show a continued decrease, which may be due in whole or part to loss by transference to the shorn sheep.

The greatest concentration during the peak infestation is on the chest, lower shoulder and lower rib wool. In winter and spring the population is more generally distributed, and may show a preference for the upper over the lower side wool. In summer the back is practically deserted and the upper sides only sparsely populated. The throat and chest region is a favoured site the year round, and there is some indication that the throat may be a breeding area.

Generally speaking, the adult and pupal populations are proportionately distributed. In late spring, however, puparia tend to be laid to a greater extent, relative to the adult population, in the lower than the upper surface fleece.

The significance of the seasonal population shifts is discussed, and a method of eradicating keds from a flock by summer dipping of the lambs is outlined.
Experiments with mice and fleas
Authors: Buxton P. A.
Published: June 2009

We need a fuller understanding of the feeding habits of fleas on rodents, both to help in the study of the epidemiology of plague and also in carrying out laboratory experiments on the same subject. In an earlier paper (Buxton, 1938) I described a ‘synthetic mouse hole’ in which I kept a rodent with a population of fleas (Xenopsylla cheopis) under controlled conditions of climate and feeding for periods of many days; with this I obtained some measure of the progeny which resulted under a variety of conditions. There was evidence that the mouse ate a number of the fleas, and I never controlled this variable, which was erratic and sometimes very large. We attempted to avoid the destruction of the fleas by feeding them on a baby mouse, which was changed at intervals, so that there was always one in the experimental vessel. In a postscript to the above paper it was shown that the baby mouse does not consume the fleas, almost all of which are alive when the experiment has lasted a week; in that period the adult mouse may eat about half or more of the fleas. Further experiments are in progress on the factors which determine the destruction of fleas by the mouse, and on the proportion of fleas which are actually found on the mouse under different conditions of temperature and so forth. In the present note, I shall confine myself to studying the baby mouse, as a host of X. cheopis. All the experiments here described were carried out between 1937 and 1939, though it has not till now proved possible to tabulate and consider the results. The execution of the work was in the hands of Mr S. Smith, whose help is acknowledged.
Two new lung nematodes from Near-East mammals
Authors: Gerichter Ch. B.
Published: June 2009

Two new species of lung nematodes from Near-East mammals are described: Crenosoma lophocara from Erinaceus roumanicus sacer and Stenuroides herpestis from Herpestes ichneumon, the latter species giving rise to establishment of a new genus of the subfamily Pseudaliinae. This species is the only known example of pseudaliin nematode parasitizing a terrestrial host.
On the male of Ascarophis morrhuae van Beneden
Authors: Gordon Ann R.
Published: June 2009

Two nematodes, a male and a female, were found in the stomach of a haddock, Gadus aeglefinus Linn.; they were lying close together and protruding from the wall of the stomach into its cavity. They were sent to Mr Stephen Prudhoe of the British Museum (N.H.), who identified them as probably Ascarophis morrhuae van Beneden. The worms were the only two nematodes found in this fish, and on account of their proximity, and the fact that they both belong to the genus Ascarophis, it is assumed that they are a pair. As the male of this species has not apparently been described so far, an account of the single specimen is given below.
A new monostome cercaria from bithynoid snails in Singapore
Authors: Jones T. W. Tyssul
Published: June 2009

Work on larval trematodes has now become worldwide in scope. Investigations have been carried out in Europe, Asia, China, Japan, Africa, the Americas, as well as certain Pacific Islands and countries in the Near East. The writer has not, however, been able to find any record of work on the Malay Peninsula or the island of Singapore. The nearest country to Malaya in which investigations have been carried out is Indo-China, where Lagrange (1923) investigated the trematodes of that country.
Clifford Dobell (1886–1949) In Memoriam
Authors: Mackinnon Doris L. , Hoare Cecil A.
Published: June 2009

When, on 23 December 1949, Clifford Dobell died as the result of an unheralded cerebral haemorrhage, the world of biological science lost a remarkable figure and thisJournalone of the most distinguished of its regular contributors. Dobell's name means much to protistologists all over the world, especially to students of the parasitic Protozoa, who recognize in him a great investigator of the animal microcosm. His contributions to the history of his science, culminating in the famous monograph on Leeu-wenhoek, reveal him also as a man of wide culture and endowed with a sense of the past such as is rare in these days.
Two skin parasites of Rana temporaria: Dermocystidium ranae Guyénot & Naville and Dermosporidium granulosum n.sp.
Authors: Broz O. , Privora M.
Published: June 2009

In the skin of Rana temporaria from Czechoslovakia two unicellular parasites have been found: Dermocystidium ranae Guyénot & Naville and Dermosporidium granulosum n.sp.

Dermocystidium ranae. Two stages were found, one of which is new. An account is given of the morphology, development and occurrence of both stages, including details which have hitherto not been recorded.

Dermosporidium granulosum n.sp. This species is represented by cysts situated in the stratum spongiosum corii. They are divided by septa into small chambers containing groups of spherical spores with a central nucleus and with numerous small cytoplasmic inclusions. Within the cyst, the sporoblasts occupy the periphery, while the ripe spores are in the centre.
How big? How fast? Transcendental Reflections on Space, Time and World Models
Authors: Wyller Truls
Published: June 2009

Of what does the size of spatially and temporally extended phenomena consist? The particular, non-conceptual magnitude of a spatial thing is a determinate, world-defining unit size. Correspondingly, natural objects have a definite size in relation to embodied human subjectivity as a global ‘measure of worlds’. As displayed by the occurrence of global models in human life, this relation has an irreducibly indexical character. The particular temporal extension of events is intrinsic to human experience as well – albeit in a different way. As displayed in local models only, it is a conceivable object of practical but not of propositional knowledge. In its role as a global spatial measure, somehow the human body is more than one among the many possible objects of descriptive knowledge. This role is supplied by rational agency – which is then a condition of the world.
PINE-SPARKY: graphical interface for evaluating automated probabilistic peak assignments in protein NMR spectroscopy
Authors: Lee Woonghee , Westler William M. , Bahrami Arash , Eghbalnia Hamid R. , Markley John L.
Published: June 2009

Summary: PINE-SPARKY supports the rapid, user-friendly and efficient visualization of probabilistic assignments of NMR chemical shifts to specific atoms in the covalent structure of a protein in the context of experimental NMR spectra. PINE-SPARKY is based on the very popular SPARKY package for visualizing multidimensional NMR spectra (T. D. Goddard and D. G. Kneller, SPARKY 3, University of California, San Francisco). PINE-SPARKY consists of a converter (PINE2SPARKY), which takes the output from an automated PINE-NMR analysis and transforms it into SPARKY input, plus a number of SPARKY extensions. Assignments and their probabilities obtained in the PINE-NMR step are visualized as labels in SPARKY's spectrum view. Three SPARKY extensions (PINE Assigner, PINE Graph Assigner, and Assign the Best by PINE) serve to manipulate the labels that signify the assignments and their probabilities. PINE Assigner lists all possible assignments for a peak selected in the dialog box and enables the user to choose among these. A window in PINE Graph Assigner shows all atoms in a selected residue along with all atoms in its adjacent residues; in addition, it displays a ranked list of PINE-derived connectivity assignments to any selected atom. Assign the Best-by-PINE allows the user to choose a probability threshold and to automatically accept as “fixed” all assignments above that threshold; following this operation, only the less certain assignments need to be examined visually. Once assignments are fixed, the output files generated by PINE-SPARKY can be used as input to PINE-NMR for further refinements.

Availability: The program, in the form of source code and binary code along with tutorials and reference manuals, is available at http://pine.nmrfam.wisc.edu/PINE-SPARKY.

Contact:  whlee@nmrfam.wisc.edu; markley@nmrfam.wisc.edu
Cloning and DNA sequence analysis of the serC-aroA operon from Salmonella gallinarum; evolutionary relationships between the prokaryotic and eukaryotic aro A-encoded enzymes
Authors: Griffin Hugh G. , Griffin Annette M.
Published: June 2009

Summary: TheserC-aroAoperon ofSalmonella gallinarumwas isolated from a gene library using a labelled oligonucleotide probe and by complementation of anaroA Escherichia colistrain. The nucleotide sequence of a 2Â·6 kbp fragment was determined. The predicted amino acid sequence of thearoAgene product was compared to the equivalent sequence from ten other organisms. Computer-generated evolutionary trees clearly divide the eleven sequences into four different groups: Gram-negative bacteria, Gram-positive bacteria, fungi and plants. These trees depict a close evolutionary relationship between the sequences from Gram-negative bacteria and higher plants.
Molecular cloning and characterization of the aroD gene encoding 3-dehydroquinase from Salmonella typhi
Authors: Servos Spiros , Chatfield Steve , Hone David , Levine Myron , Dimitriadis George , Pickard Derek , Dougan Gordon , Fairweather Neil , Charles Ian
Published: June 2009

The aroD gene from Salmonella typhi, encoding 5-dehydroquinate hydrolyase (3-dehydroquinase), has been cloned into Escherichia coli and the DNA sequence determined. The aroD gene was isolated from a cosmid gene bank by complementation of an S. typhimurium aroD mutant. Analysis of the DNA sequence revealed the presence of an open reading frame capable of encoding a protein of 252 amino acids with a calculated M
r of 27706. Comparison of the deduced S. typhi 3-dehydroquinase protein sequence with that elucidated for E. coli revealed 69 % homology. Alignment of the S. typhi sequence and equivalent Aspergillus nidulans and Saccharomyces cerevisiae sequences showed that homology was lower, at 24%, but still significant. Use of a minicell expression system demonstrated that a polyclonal antibody raised against E. coli 3-dehydroquinase cross-reacted with its S. typhi counterpart.
Differentiation of virescence MLOs using western aster yellows mycoplasma-like organism chromosomal DNA probes and restriction fragment length polymorphism analysis
Authors: Kuske Cheryl R. , Kirkpatrick Bruce C. , Seemüller Erich
Published: June 2009

Summary: Two chromosomal fragments of the severe strain (SAY) of the western aster yellows mycoplasma-like organism (MLO) were cloned in Escherichia coli. These fragments were used to probe Southern blots of DNA extracted from plants infected with geographically and pathologically diverse MLOs. The two SAY probes hybridized with some, but not all, of the virescence-inducing MLOs examined, indicating that some of these MLOs are genetically related. Comparisons of restriction fragment length polymorphisms of MLO DNA established additional relationships within this group. The SAY-MLO probes did not hybridize with decline-inducing MLOs, plant pathogenic spiroplasmas, or healthy plants.
Polar lipids and fatty acids of Pseudomonas caryophylli, Pseudomonas gladioli and Pseudomonas pickettii
Authors: Galbraith Lesley , Wilkinson Stephen G.
Published: June 2009

The polar lipids and their fatty acid components in Pseudomonas caryophylli, Pseudomonas gladioli and Pseudomonas pickettii have been identified. In addition to diphosphatidylglycerol and phosphatidylglycerol (a trace only for P. pickettii), all three species contained two forms of phosphatidylethanolamine differing in the presence or absence of α-hydroxy fatty acids. This seems to be a distinctive feature of species in Pseudomonas RNA homology group II. Also, P. caryophylli and P. gladioli (but not P. pickettii) produced two forms of ornithine amide lipid, differing in the nature (hydroxy or non-hydroxy) of the ester-linked fatty acid. In all three species, the major non-hydroxy acids were hexadecanoic acid, a hexadecenoic acid, an octadecenoic acid, and cyclopropane derivatives of the monoenoic acids. The α-hydroxy acids were the derivatives of the same components, while the amide-linked acid of the ornithine amide lipids was mainly or entirely 3-hydroxyhexadecanoic acid. The possible taxonomic implications of the data are discussed.
Production and characterization of monoclonal antibodies to outer membrane proteins of Pseudomonas aeruginosa grown in iron-depleted media
Authors: Smith Anthony W. , Wilton Jane , Clark Stuart A. , Alpar Oya , Melling Jack , Brown Michael R. W.
Published: June 2009

The iron uptake systems of pathogenic bacteria provide potential targets for immunological intervention. We have partially purified the high molecular mass, iron-regulated outer membrane proteins (IROMPs) from Pseudomonas aeruginosa and used them to prepare a panel of monoclonal antibodies (mAbs). Five mAbs reacted with an 85 kDa IROMP separated by SDS-PAGE, but gave only low-level binding to whole cells by immunogold electron microscopy. However, iodination of whole cells indicated that the 85 kDa IROMP is surface-exposed. The mAbs were only cross-reactive with clinical isolates representing eight of the 17 International Antigenic Typing Scheme serotypes of P. aeruginosa, suggesting significant heterogeneity with respect to this IROMP.
Involvement of the CDC25 gene product in the signal transmission pathway of the glucose-induced RAS-mediated cAMP signal in the yeast Saccharomyces cerevisiae
Authors: Van Aelst Linda , Jans Arnold W. H. , Thevelein Johan M.
Published: June 2009

Addition of glucose or related fermentable sugars to derepressed cells of the yeast Saccharomyces cerevisiae triggers a RAS-protein-mediated cAMP signal, which induces a protein phosphorylation cascade. Yeast strains without a functional CDC25 gene were deficient in basal cAMP synthesis and in the glucose-induced cAMP signal. Addition of dinitrophenol, which in wild-type strains strongly stimulates in vivo cAMP synthesis by lowering intracellular pH, did not enhance the cAMP level. cdc25 disruption mutants, in which the basal cAMP level was restored by the RAS2
va119 oncogene or by disruption of the gene (PDE2) coding for the high-affinity phosphodiesterase, were still deficient in the glucose- and acidification-induced cAMP responses. These results indicate that the CDC25 gene product is required not only for basal cAMP synthesis in yeast but also for specific activation of cAMP synthesis by the signal transmission pathway leading from glucose to adenyl cyclase. They also show that intracellular acidification stimulates the pathway at or upstream of the CDC25 protein. When shifted to the restrictive temperature, cells with the temperature sensitive cdc25-5 mutation lost their cAMP content within a few minutes. After prolonged incubation at the restrictive temperature, cells with this mutation, and also those with the temperature sensitive cdc25-1 mutation, arrested at the ‘start’ point (in G1) of the cell cycle, and subsequently accumulated in the resting state G0. In contrast with cdc25-5 cells, however, the cAMP level did not decrease and normal glucose- and acidification-induced cAMP responses were observed when cdc25-1 cells were shifted to the restrictive temperature. These results show that, in the original genetic background at least, growth arrest of cdc25-1-bearing cells at the restrictive temperature is not due to cAMP deficiency. Previous experiments have provided evidence for the presence of a glucose-repressible protein in the signalling pathway. Exponential-phase glucose-grown cells of a strain with overexpression of CDC25 unexpectedly showed a glucose-induced cAMP signal. Control experiments, however, indicated that overexpression of CDC25 caused a defect in glucose repression. Introduction of the cat1 derepression mutation in the strain with overexpression of CDC25 restored glucose repression and abolished the glucose-induced cAMP signal, indicating that the CDC25 protein is not the glucose-repressible component of the signalling pathway.
Mutations affecting germination in Myxococcus xanthus
Authors: Elías Montserrat , Murillo Francisco J.
Published: June 2009

Myxococcus xanthus mutants defective in myxospore germination have been isolated both by a selective and by a non-selective method after UV or Tn5-lac-induced mutagenesis. The ability of these mutants to germinate in germinant solutions other than those used for their isolation has been tested. Six of seven mutants isolated behaved as germination-defective in all germinants. Germination of the seventh mutant was conditional on the germinant used, being normal in Casamino acids but defective in a Casitone-based medium. Genetic analysis of the four mutant strains carrying Tn5-lac insertions revealed that the transposon had disrupted a different locus in each mutant, so that the four mutants defined four unlinked loci involved in the germination process (gerA, gerB, gerC, gerD). Strain MR307 was studied in more detail. Cloning of the gene affected in this mutant, gerC, and construction of merodiploids revealed that the wild-type allele is dominant over the mutated one. In vitro construction of lacZ fusions allowed study of gerC expression throughout the M. xanthus life cycle, revealing that the gene affected by insertion at ΩMR307 is developmentally regulated.
Epitopes of Bordetella pertussis lipopolysaccharides as potential markers for typing of isolates with monoclonal antibodies
Authors: Blay Karine Le , Caroff Martine , Blanchard Frédéric , Perry Malcolm B. , Chaby Richard
Published: June 2009

Three hybridomas (P1P3, D7 and 60.5) producing monoclonal antibodies (mAbs) against Bordetella pertussis lipopolysaccharide (LPS) were established. All reacted with the LPS from a typical, vaccine strain of B. pertussis (1414), but not with that of a variant strain (A100). Two of these mAbs (P1P3 and 60.5) cross-reacted with a B. bronchiseptica LPS; only one (P1P3) reacted with a B. parapertussis LPS. ELISA reactivities with intact LPSs, and defined partial structures covalently linked to bovine serum albumin, were compared. mAb 60.5 bound to the terminal region of a distal trisaccharide consisting of N-acetylated amino sugars. D7 reacted with a substructure which can be modified in the B. parapertussis and B. bronchiseptica LPSs by addition of a polymeric O-chain. P1P3 bound to a nonacetylated glucosamine substituted with L-glycero-D-manno-heptose, present in the ‘core’ of the B. pertussis LPS. These mAbs may be useful for rapid typing of Bordetella in clinical isolates.
A Bacillus Cereus Member of the SNF2 Family
Authors: Lindbäck Toril , Kolstø Anne-Brit
Published: June 2009

The complete sequence of a Bacillus cereus member of the SNF2 family of putative helicases showed conservation of all seven motifs typical of this family. Bcsnf predicted a protein of 1064 aa where the conserved SNF2 domain was located at the carboxy terminus, whereas the 633 amino-terminal aa showed no homology to any protein in the databases. A putative transcriptional start was identified by primer extension, indicating that Bcsnf is not a part of a larger operon. No phenotypical changes were observed after insertional inactivation of Bcsnf. The completely sequenced genomes of Mycoplasma genitalium and Haemophilus influenzae contain one ORF each with similarity to the SNF2 family: MG018 and HI0616, respectively. A phylogenetic tree of the SNF2 family showed that BcSNF and MG018 were most closely related, and appeared closer to the eukaryotic members of the SNF2 family than to the two other bacterial members of the family, HepA from Escherichia coli and HI0616.
The IdhA Gene Encoding the Fermentative Lactate Dehydrogenase of Escherichia Coli
Authors: Bunch Pamela K. , Mat-Jan Fairoz , Lee Norizan , Clark David P.
Published: June 2009

Under anaerobic conditions, especially at low pH, Escherichia coli converts pyruvate to D-lactate by means of an NADH-linked lactate dehydrogenase (LDH). This LDH is present in substantial basal levels under all conditions but increases approximately 10-fold at low pH. The IdhA gene, encoding the fermentative lactate dehydrogenase of E. coli, was cloned using λ10E6 of the Kohara collection as the source of DNA. The IdhA gene was subcloned on a 2.8 kb MIuI-MIuI fragment into a multicopy vector and the region encompassing the gene was sequenced. The IdhA gene of E. coli was highly homologous to genes for other D-lactate-specific dehydrogenases but unrelated to those for the L-lactate-specific enzymes. We constructed a disrupted derivative of the IdhA gene by inserting a kanamycin resistance cassette into the unique KpnI site within the coding region. When transferred to the chromosome, the IdhA::Kan construct abolished the synthesis of the D-LDH completely. When present in high copy number, the IdhA gene was greatly overexpressed, suggesting escape from negative regulation. Cells expressing high levels of the D-LDH grew very poorly, especially in minimal medium. This poor growth was largely counteracted by supplementation with high alanine or pyruvate concentrations, suggesting that excess LDH converts the pyruvate pool to lactate, thus creating a shortage of 3-carbon metabolic intermediates. Using an IdhA-cat gene fusion construct we isolated mutants which no longer showed pH-dependent regulation of the IdhA gene. Some of these appeared to be in the pta gene, which encodes phosphotransacetylase, suggesting the possible involvement of acetyl phosphate in IdhA regulation.
The Lipid a Biosynthesis Deficiency of the Escherichia Coli Antibiotic-Supersensitive Mutant LH530 is Suppressed by a Novel Locus, ORF195
Authors: Hirvas Laura , Nurminen Marjatta , Helander Ilkka M. , Vuorio Riitta , Vaara Martti
Published: June 2009

A new mutant of Escherichia coli K-12 supersensitive to both hydrophobic and large hydrophilic antibiotics was isolated and characterized. The mutant grew well at 28 °C, poorly at 37 °C, and did not grow at 42 °C. The rate of its lipid A biosynthesis was reduced as compared to that of the parent strain. This deficiency was rescued by a novel locus, ORF195, the function of which has not been elucidated. ORF195 is located in the 76 min region in the E. coli chromosome and encodes a hypothetical 21.8 kDa protein with no signal sequence. ORF195 isolated from the mutant strain had an identical sequence to the wild-type allele, indicating a suppressor function of the gene product.
Transcriptional control of several aerobically induced cytochrome structural genes in Rhodobacter sphaeroides
Authors: Flory Janice E. , Donohue Timothy J.
Published: June 2009

To decipher how the synthesis of energy-transducing enzymes responds to environmental cues, the response of three Rhodobacter sphaeroides aerobic cytochrome gene promoters was analysed under different conditions. Two of these promoters are upstream of structural genes (ctaD and coxII) for individual subunits of the cytochrome aa
3 respiratory complex. The third promoter is that for the cycFG operon, which encodes two c-type cytochromes of unknown function, cytochrome c
554 and CycG. Primer extension analysis identified a single oxygen-responsive transcription start site for each gene. Utilizing operon fusions to Escherichia coli lacZ as a measure of promoter activity, transcription from the ctaD, coxII and cycFG promoters was approximately twofold higher when cells were grown at high (30%) oxygen tensions than under low (2%) oxygen or anaerobic (photosynthetic) conditions. Analysis of promoter function using specific host mutations indicated that loss of the R. sphaeroides FNR homologue, FnrL, causes a small, but reproducible, increase in cycFG and coxII transcription when cells are grown at 2% oxygen. However, neither the ΔFnrL mutation nor alterations in sequences related to a consensus target site for the E. coli FNR protein increased function of any of these three promoters to that seen under aerobic conditions in wild-type cells. From this we conclude that FnrL is not solely responsible for reduced transcription of these three aerobic cytochrome genes under low oxygen or anaerobic conditions. When activity of these three promoters was monitored after cells were shifted from anaerobic (photosynthetic) conditions to a 30% oxygen atmosphere, it took several cell doublings for LacZ levels to increase to those found in steady-state 30% oxygen cultures. From these results, it appears that activity of these promoters is also regulated by a stable molecule whose synthesis or function responds slowly to the presence of high oxygen tensions.
The immunoreactive 116 kDa surface protein of Mycoplasma pneumoniae is encoded in an operon
Authors: Duffy Michael F. , Walker Ian D. , Browning Glenn F.
Published: June 2009

Sera from 10 patients infected withMycoplasma pneumoniaewere used in Western blot analysis of Triton-X-114-soluble protein preparations ofM. pneumoniae.All 10 sera were reactive with a protein antigen of 116 kDa. Sera from another 17 patients were used in Western blot analysis of whole-cellM. pneumoniaeproteins; 15 of these sera were reactive with the 116 kDa protein. Trypsin digestion of wholeM. pneumoniaecells demonstrated the surface location of this protein. Sequencing of DNA which contained the gene for this protein identified an ORF of 3093 bp encoding a protein with a predicted molecular mass of 116013 Da. The ORF for the 116 kDa protein had 99·8% nucleotide identity with theM. pneumoniaegene G07_orf1030 and 61% nucleotide identity with the Mycoplasma genitalium ORF MG075 of unassigned function. An ORF which was identified 5' to the 116 kDa protein ORF coded for a 16 kDa protein and had 99·8% nucleotide identity with theM. pneumoniaegene G07_orf135 and 58·4% nucleotide identity with the ORF MG074 ofM. genitalium.Analysis of mRNA detected a 3·7 kb transcript with a single initiation site 5' to the ORF encoding the 16 kDa protein. The coding sequences for both the 16 kDa protein and the 116 kDa protein were present in this transcript, indicating that they were part of an operon and suggesting a possible functional relationship.
Sequencing and functional annotation of the Bacillus subtilis genes in the 200 kb rrnB-dnaB region
Authors: Lapidus Alia , Galleron Nathalie , Sorokin Alexei , Ehrlich S. Dusko
Published: June 2009

The 200 kb region of the Bacillus subtilis chromosome spanning from 255 to 275° on the genetic map was sequenced. The strategy applied, based on use of yeast artificial chromosomes and multiplex Long Accurate PCR, proved to be very efficient for sequencing a large bacterial chromosome area. A total of 193 genes of this part of the chromosome was classified by level of knowledge and biological category of their functions. Five levels of gene function understanding are defined. These are: (i) experimental evidence is available of gene product or biological function; (ii) strong homology exists for the putative gene product with proteins from other organisms; (Hi) some indication of the function can be derived from homologies with known proteins; (iv) the gene product can be clustered with hypothetical proteins; (v) no indication on the gene function exists. The percentage of detected genes in each category was: 20, 28, 20, 15 and 17, respectively. In the sequenced region, a high percentage of genes are implicated in transport and metabolic linking of glycolysis and the citric acid cycle. A functional connection of several genes from this region and the genes close to 140° in the chromosome was also observed.
Quorum sensing and Chromobacterium violaceum: exploitation of violacein production and inhibition for the detection of N-acylhomoserine lactones
Authors: McClean Kay H. , Winson Michael K. , Fish Leigh , Taylor Adrian , Chhabra Siri Ram , Camara Miguel , Daykin Mavis , Lamb John H. , Swift Simon , Bycroft Barrie W. , Stewart Gordon S. A. B. , Williams Paul
Published: June 2009

Quorum sensing relies upon the interaction of a diffusible signal molecule with a transcriptional activator protein to couple gene expression with cell population density. In Gram-negative bacteria, such signal molecules are usually N-acylhomoserine lactones (AHLs) which differ in the structure of their N-acyl side chains. Chromobacterium violaceum, a Gram-negative bacterium commonly found in soil and water, produces the characteristic purple pigmen violacein. Previously the authors described a violacein-negative, mini-Tn5 mutant of C. violaceum (CV026) in which pigment production can be restored by incubation with supernatants from the wild-type strain. To develop this mutant as a general biosensor for AHLs, the natural C. violaceum AHL molecule was first chemically characterized. By using solvent extraction, HPLC and mass spectrometry, a single AHL, N-hexanoyl-L-homoserine lactone (HHL), was identified in wild-type C. violaceum culture supernatants which was absent from CV026. Since the production of violacein constitutes a simple assay for the detection of AHLs, we explored the ability of CV026 to respond to a series of synthetic AHL and N-acylhomocysteine thiolactone (AHT) analogues. In CV026, violacein is inducible by ail the AHL and AHT compounds evaluated with N-acyl side chains from C4 to C8 in length, with varying degrees of sensitivity. Although AHL compounds with N-acyl side chains from C10 to C14 are unable to induce violacein production, if an activating AHL (e.g. HHL) is incorporated into the agar, these long-chain AHLs can be detected by their ability to inhibit violacein production. The versatility of CV026 in facilitating detection of AHL mixtures extracted from culture supernatants and separated by thin-layer chromatography is also demonstrated. These simple bioassays employing CV026 thus greatly extend the ability to detect a wide spectrum of AHL signa molecules.
Cytochemical studies of cell viability and gene expression in Bacillus subtilis macrofibres
Authors: Mendelson Neil H. , Salhi Bachira , Sundahl Katherine E.
Published: June 2009

The viability of cells and the expression of a reporter gene in Bacillus subtilis macrofibres have been examined using cytochemical approaches. Previous studies have shown that macrofibres grow at an exponential rate in fluid environments and undergo complex dynamic motions as they elongate but the behaviour of individual cells in them has never been examined. A fluorescence staining procedure that distinguishes living cells from dead cells was used in the experiments described to examine cells in both left- and right-handed macrofibres. Very few dead cells were found in individual fibres. Their locations appeared to be random, suggesting that neither the extreme shape deformation imposed upon cells in the loop ends of fibres, nor the entrapment of cells in the interior of a fibre compromise viability. In related experiments, initial studies of reporter gene expression during fibre morphogenesis were conducted using a strain previously studied as conventional colonies. Spatial and temporal differences in the appearance of the blue cleavage product of X-Gal were found, suggesting that differential gene expression may arise in macrofibres in contrast to the results found in colonies. Two conclusions may be drawn from the findings: (i) virtually all cells in macrofibres are viable and (ii) all the cells in macrofibres do not always behave in an identical manner.
Effect of carbon substrate and aeration on nitrate reduction and expression of the periplasmic and membrane-bound nitrate reductases in carbon-limited continuous cultures of Paracoccus denitrificans Pd1222
Authors: Sears Heather J. , Spiro Stephen , Richardson David J.
Published: June 2009

The expression andin situactivity of the membrane-bound and periplasmic nitrate reductases have been assayed inParacoccus denitrificansPd1222 grown under a range of aeration regimes in malate-limited or butyrate-limited chemostat cultures. In butyrate-limited cultures the expression of periplasmic nitrate reductase and the rate ofin situnitrate reduction were high at all oxygen concentrations measured between 0% and 100% air saturation. By contrast, in malate-limited cultures expression of the periplasmic nitrate reductase was low at 80-100% air saturation but increased to a maximum between 20% and 50% air saturation. Aerobic nitrate reduction was much higher in butyrate-limited than in malate-limited cultures, demonstrating a significant role for this process during butyrate metabolism. The rate of nitrate respiration increased in both the malate- and butyrate-limited cultures as aerobic metabolism switched completely to anaerobic metabolism. Expression of the membrane-bound nitrate reductase could be detected in butyrate-limited chemostat cultures maintained at an oxygen level of 100% air saturation. No membrane-bound nitrate reductase was detectable under similar conditions in malate-limited cultures but expression was detected at oxygen concentrations of 50% air saturation and below. Taken together, the results show that the nature of the carbon substrate and oxygen concentration can both influence expression of the periplasmic and membrane-bound nitrate reductases. The conditions under which expression of the periplasmic nitrate reductase and aerobic nitrate respiration are maximal can be rationalized in terms of a role for the periplasmic nitrate reductase in dissipating excess reductant generated during oxidative metabolism of reduced carbon substrates.
The haemagglutinin of Clostridium botulinum type C progenitor toxin plays an essential role in binding of toxin to the epithelial cells of guinea pig small intestine, leading to the efficient absorption of the toxin
Authors: Fujinaga Yukako , Inoue Kaoru , Watanabe Sadahiro , Yokota Kenji , Hirai Yoshikazu , Nagamachi Eiko , Oguma Keiji
Published: June 2009

Binding of the purified type C 7S (neurotoxin), 12S and 16S botulinum toxins to epithelial cells of ligated small intestine or colon of the guinea pig (in vivotest) and to pre-fixed gastrointestinal tissue sections (in vitrotest) was analysed. The 16S toxin bound intensely to the microvilli of epithelial cells of the small intestine in bothin vivoandin vitrotests, but did not bind to cells of the stomach or colon. The neurotoxin and 12S toxin did not bind to epithelial cells of the small intestine or to cells of the stomach or colon. Absorption of the toxins was assessed by determining the toxin titre in the sera of guinea pigs 6-8 h after the intra-intestinal administration of the toxins. When the 16S toxin [1 x 105minimum lethal dose (MLD)] was injected, 200-660 MLD ml-1was detected in the sera, whereas when the 12S toxin (2 x 105MLD) or 7S toxin (2 x 105MLD) was injected, little toxin activity was detected in the sera. Therefore, the haemagglutinin of type C 16S toxin is apparently very important in the binding and absorption of botulinum toxin in the small intestine.