bluuebunny/crossref_metadata_2025 huggingface dataset:
Pairs of extreme avian personalities have highest reproductive success
Authors: BOTH CHRISTIAAN , DINGEMANSE NIELS J. , DRENT PIET J. , TINBERGEN JOOST M.
Published: July 2005

Intraspecific variation in reproductive decisions is generally considered as a reaction to environmental circumstances. We show that variation in reproductive parameters also covaries with intraspecific variation in personality.

During 4 years, we studied reproductive parameters in a natural population of great tits in association with a personality trait: exploratory behaviour as measured in a novel environment.

Nest success, fledgling size and condition were all correlated with this personality trait. Slow‐exploring females had a higher nest success and largest fledglings. Fledgling condition was affected by the interaction between male and female exploratory behaviour, with assortative pairs at both ends of the behavioural spectrum producing fledglings in best condition. Fast‐exploring males bred in nestboxes that produced heavy fledglings in other years.

We hypothesize that fast‐exploring individuals are better able in defending or obtaining a high quality territory, while slow‐exploring individuals are either better parents or have better chicks which may, in part, explain the patterns in reproductive success. We discuss how these patterns in reproduction can explain earlier reported relationships between offspring recruitment and avian personality and may result in the maintenance of intraspecific genetic variation in personality.
Maternal yolk testosterone does not modulate parasite susceptibility or immune function in great tit nestlings
Authors: TSCHIRREN BARBARA , SALADIN VERENA , FITZE PATRICK S. , SCHWABL HUBERT , RICHNER HEINZ
Published: July 2005

Maternal yolk hormones can enhance the development and phenotypic quality of nestling birds. Nevertheless, within species large differences in yolk androgen concentrations among clutches are observed. This differential allocation of maternal yolk hormones might be explained by a trade‐off between beneficial effects of yolk androgens and their associated costs.

Potential costs include an increased susceptibility to parasites in nestlings exposed to high concentrations of yolk androgens during embryonic development, weaker immune response or increased levels of circulating corticosterone that indirectly reduce immune function.

In a field study, we manipulated yolk testosterone in great tit (Parus major) eggs and tested the nestling's susceptibility to ectoparasites as measured by the parasites’ effect on growth, the cellular immune response, and the levels of circulating corticosterone.

At the end of the nestling period, nestlings originating from testosterone‐injected eggs were heavier than control nestlings. This effect was strongest in nestlings at the end of the size hierarchy, as shown by a significant interaction between hormone treatment and the nestlings’ size rank within nests.

High levels of yolk testosterone promoted growth of the nestling's body mass similarly in parasite‐infested and parasite‐free nests, and neither affected the levels of plasma corticosterone, nor the nestling's cell‐mediated immune response.

In summary, our results do not show negative short‐term effects of high concentrations of yolk testosterone on immune function or parasite susceptibility, but emphasize that maternal investment via deposition of yolk testosterone can promote fitness‐related growth and development of nestlings.
An experimental study on the causes of sex‐biased mortality in the black‐headed gull − the possible role of testosterone
Authors: MÜLLER WENDT , GROOTHUIS TON G. G. , EISING CORINE M. , DIJKSTRA COR
Published: July 2005

During early development male offspring in avian species often suffer from enhanced mortality compared to female offspring. This has been attributed to different nutritional requirements, as sex‐biased mortality has been reported particularly in sexually size‐dimorphic species. However, other traits of the male phenotype, such as the embryonic hormone profile, have been suggested to contribute to this male disadvantage. In particular the negative effects of sex steroids on immune function may be causally involved.

We investigated the role of testosterone in the expression of male phenotype disadvantage through an experimental reduction of the availability of testosterone receptors by in‐ovo injection of an anti‐androgen (Flutamide©). Experimental nests contained a male and a female chick hatching from control treated eggs and a male and a female chick hatching from Flutamide treated eggs.

Male‐biased mortality occurred in control chicks at a stage where the sexes did not yet differ in their growth pattern, suggesting that sex‐specific nutritional requirements are not necessary for male‐biased mortality to occur. Control males and control females did not differ in their cell‐mediated immunity (CMI). This renders it unlikely that the observed skewed mortality was due to sex‐specific differences in the CMI.

Treatment of the eggs with flutamide antagonistically affected males and females. Flutamide treatment positively affected male development in particular through an enhanced growth rate, indicating that testosterone is involved in the expression of the male phenotype disadvantage. Female chicks hatching from Flutamide treated eggs were disadvantaged in growth and CMI. The possible pathways of this sex‐specific effect of Flutamide are discussed with regard to differential consequences of blocking the beneficial effects of maternal androgens and the interference with the process of sexual differentiation in males.
Space–time clustering of cowpox virus infection in wild rodent populations
Authors: CARSLAKE DAVID , BENNETT MALCOLM , BOWN KEVIN , HAZEL SARAH , TELFER SANDRA , BEGON MICHAEL
Published: July 2005

The spatial and temporal scale at which infectious animals pose a transmission risk to others may be inferred by a study of space–time interaction in the clustering of cases of infection.

We analyse the distribution of bank voles and wood mice infectious with cowpox virus, using 7 years of monthly live‐trapping data from a woodland in north‐west England.

A published method,K‐function analysis, is adapted to measure space–time interaction among infectious animals trapped on a grid system, where the populations at risk may vary in density.

We hypothesized that the risk of cowpox transmission from an infectious animal would be contained within a temporal scale of one infectious period and a spatial scale of one home‐range diameter.

Cowpox cases among wood mice showed significantly greater spatial clustering than the population at risk at the smallest spatial scale, corresponding to animals caught in the same location. At larger scales, and for bank voles at all scales, cowpox cases showed no spatial clustering beyond that expected from an association with host distribution.

Cowpox cases among wood mice showed strong evidence of temporal clustering beyond that of the host population, indicating short‐lived outbreaks. No such effect was apparent among bank voles.

Significant space–time interaction among cowpox cases was detected at the hypothesized spatial and temporal scales in both host species. This suggests that the risk of transmission is concentrated locally.

Results are discussed in terms of transmission, including consideration of the appropriateness of distance and nearest‐neighbour based clustering tests to infections transmitted by local density and frequency dependent mechanisms.
Habitat‐specific normal and reverse diel vertical migration in the plankton‐feeding basking shark
Authors: SIMS DAVID W. , SOUTHALL EMILY J. , TARLING GERAINT A. , METCALFE JULIAN D.
Published: July 2005

Megaplanktivores such as filter‐feeding sharks and baleen whales are at the apex of a short food chain (phytoplankton–zooplankton–vertebrate) and are sensitive indicators of sea‐surface plankton availability. Even though they spend the majority of their time below the surface it is still not known how most of these species utilize vertical habitat and adapt to short‐term changes in food availability.

A key factor likely to control vertical habitat selection by planktivorous sharks is the diel vertical migration (DVM) of zooplankton; however, no study has determined whether specific ocean‐habitat type influences their behavioural strategy. Based on the first high‐resolution dive data collected for a plankton‐feeding fish species we show that DVM patterns of the basking shark Cetorhinus maximus reflect habitat type and zooplankton behaviour.

In deep, well‐stratified waters sharks exhibited normal DVM (dusk ascent–dawn descent) by tracking migrating sound‐scattering layers characterized by Calanus and euphausiids. Sharks occupying shallow, inner‐shelf areas near thermal fronts conducted reverse DVM (dusk descent–dawn ascent) possibly due to zooplankton predator–prey interactions that resulted in reverse DVM of Calanus.

These opposite DVM patterns resulted in the probability of daytime‐surface sighting differing between these habitats by as much as two orders of magnitude. Ship‐borne surveys undertaken at the same time as trackings reflected these behavioural differences.

The tendency of basking sharks to feed or rest for long periods at the surface has made them vulnerable to harpoon fisheries. Ship‐borne and aerial surveys also use surface occurrence to assess distribution and abundance for conservation purposes. Our study indicates that without bias reduction for habitat‐specific DVM patterns, current surveys could under‐ or overestimate shark abundance by at least 10‐fold.
Correlates of survival rates for 10 African ungulate populations: density, rainfall and predation
Authors: OWEN‐SMITH NORMAN , MASON DARRYL R. , OGUTU JOSEPH O.
Published: July 2005

Through reconciling census totals with population structure, annual survival rates were estimated for the juvenile, yearling and adult stages of 10 ungulate species over 14 years or longer in South Africa's Kruger National Park. During this period four species maintained high abundance levels, while six species declined progressively in abundance.

Multiple regression models fitted to these estimates indicated that juvenile survival was sensitive to annual variability in rainfall for most of these species, especially in the dry season component, but with no density feedback apparent. Rainfall components affected adult survival in several of the declining species, while negative density dependence in adult survival was evident for three of the four species that maintained high abundance. A negative effect of past prey availability, indexing putative changes in predator abundance, on adult survival was more strongly supported statistically among the declining species than the lagged effect of prior rainfall, potentially affecting herbaceous vegetation cover and composition.

The high sensitivity of juvenile survival to environmental variability among these ungulate species was consistent with the general pattern identified for large mammalian herbivores, although the absence of any survival response counteracting the density declines was surprising. The susceptibility of adult survival to environmental influences for the declining species appeared unusual and probably reflected an interaction between nutritional shortfalls and a numerical increase in lions, preying largely upon the adult segment of these species. The ungulate species that persisted at high abundance seemed resistant to effects of rainfall on food resources and evidently drove the changes in predator abundance. The sharp density effect on adult survival among these species could indicate prey switching by lions following changes in their relative availability.

Findings extend past generalizations about the demographic processes underlying the population dynamics of large mammalian herbivores and reveal how the survival rates of particular population segments respond differently to environmental influences. Demographic patterns help reveal the interplay of changing resource supplies, predation pressure and population abundance on population changes.
Decomposing the variation in population growth into contributions from multiple demographic rates
Authors: COULSON TIM , GAILLARD JEAN‐MICHEL , FESTA‐BIANCHET MARCO
Published: July 2005

The decomposition of variation in population growth into the relative contributions from different demographic rates has multiple uses in population, conservation and evolutionary biology. Recent research has favoured methods based on matrix models termed ‘life‐table‐response experiments’ or more generally ‘the retrospective matrix method’, which provide an approximation of a complete demographic decomposition. The performance of the approximation has not been assessed.

We compare the performance of the retrospective matrix method to a complete decomposition for two bighorn sheep populations and one red deer population.

Different demographic rates make markedly different contributions to variation in growth rate between populations, because each population is subject to different types of environmental variation.

The most influential demographic rates identified from decomposing observed variation in population growth are often not those showing the highest elasticity. Consequently, those demographic rates most strongly associated with deterministic population growth are not necessarily strongly associated with temporal variation in population growth.

The retrospective matrix method provides a good approximation of the demographic rate associated most strongly with variation in population growth. However, failure to incorporate the contribution of covariation between demographic rates when decomposing variation in population growth can lead to spurious conclusions.
Pharmacokinetics of morphine and plasma concentrations of morphine‐6‐glucuronide following morphine administration to dogs
Authors: KUKANICH B. , LASCELLES B. D. X. , PAPICH M. G.
Published: July 2005

The purpose of this study was to evaluate the pharmacokinetics of morphine and morphine‐6‐glucuronide (M‐6‐G) following morphine administered intravenously and orally to dogs in a randomized crossover design. Six healthy 3–4‐year‐old Beagle dogs were administered morphine sulfate (0.5 mg/kg) as an i.v. bolus and extended release tablets were administered orally as whole tablets (1.6 ± 0.1 mg/kg) in a randomized crossover design. Plasma concentrations of morphine and M‐6‐G were determined using high‐pressure liquid chromatography and electrochemical coulometric detection. Following i.v. administration all dogs exhibited dysphoria and sedation, and four or six dogs vomited. Mean ± SE values for half‐life, apparent volume of distribution, and clearance after i.v. administration were 1.16 ± 0.15 h, 4.55 ± 0.17 L/kg, and 62.46 ± 10.44 mL/min/kg, respectively. One dog vomited following oral administration and was excluded from the oral analysis. Oral bioavailability was 5% as determined from naïve‐averaged analysis. The M‐6‐G was not detected in any plasma samples following oral or i.v. administration of morphine at a 25 ng/mL the limit of quantification. Computer simulations concluded morphine sulfate administered 0.5 mg/kg intravenously every 2 h would maintain morphine plasma concentrations consistent with analgesic plasma concentrations in humans. Oral morphine is poorly and erratically absorbed in dogs.
Plasma and interstitial fluid pharmacokinetics of enrofloxacin, its metabolite ciprofloxacin, and marbofloxacin after oral administration and a constant rate intravenous infusion in dogs
Authors: BIDGOOD T. L. , PAPICH M. G.
Published: July 2005

Enrofloxacin and marbofloxacin were administered to six healthy dogs in separate crossover experiments as a single oral dose (5 mg/kg) and as a constant rate IV infusion (1.24 and 0.12 mg/h·kg, respectively) following a loading dose (4.47 and 2 mg/kg, respectively) to achieve a steady‐state concentration of approximately 1 μg/mL for 8 h. Interstitial fluid (ISF) was collected with anin vivoultrafiltration device at the same time period as plasma to measure protein unbound drug concentrations at the tissue site and assess the dynamics of drug distribution. Plasma and ISF were analyzed for enrofloxacin, its active metabolite ciprofloxacin, and for marbofloxacin by high performance liquid chromatography (HPLC). Lipophilicity and protein binding of enrofloxacin were higher than for marbofloxacin and ciprofloxacin. Compared to enrofloxacin, marbofloxacin had a longer half‐life, higherCmax, and largerAUC0−∞in plasma and ISF after oral administration. Establishing steady state allowed an assessment of the dynamics of drug concentrations between plasma and ISF. The ISF and plasma‐unbound concentrations were similar during the steady‐state period despite differences in lipophilicity and pharmacokinetic parameters of the drugs.
Pharmacokinetic‐pharmacodynamic integration of moxifloxacin in rabbits after intravenous, intramuscular and oral administration
Authors: FERNÁNDEZ‐VARÓN E. , BOVAIRA M. J. , ESPUNY A. , ESCUDERO E. , VANCRAEYNEST D. , CÁRCELES C. M.
Published: July 2005

The pharmacokinetics of moxifloxacin was studied following intravenous (i.v.), intramuscular (i.m.) and oral dose of 5 mg/kg to healthy white New Zealand rabbits (n = 6). Moxifloxacin concentrations were determined by HPLC assay with fluorescence detection. The moxifloxacin plasma concentration vs. time data after i.v. administration could best be described by a two‐compartment open model. The disposition of i.m. and orally administered moxifloxacin was best described by a one‐compartment model. The plasma moxifloxacin clearance (Cl) for the i.v route was (mean ± SD) 0.80 ± 0.02 L/h·kg. The steady‐state volume of distribution (Vss) was 1.95 ± 0.18 L/kg. The terminal half‐life (t1/2λz) was (mean ± SD) 1.84 ± 0.12, 2.09 ± 0.05 and 2.15 ± 0.07 h after i.v., i.m. and oral, respectively. Minimal inhibitory concentration (MIC) assays of moxifloxacin against different strains ofS. aureuswere performed in order to compute pharmacodynamic surrogate markers. From these data, it is concluded that a 5 mg/kg dose moxifloxacin would be effective by i.m. and oral routes in rabbits against bacterial isolates withMIC ≤ 0.06 μg/mL and possibly forMIC ≤ 0.12 μg/mL, but in the latter case a higher dose would be required.
Liver microsomal biotransformation of albendazole in deer, cattle, sheep and pig and some related wild breeds
Authors: VELÍK J. , BALIHAROVÁ V. , SKÁLOVÁ L. , SZOTÁKOVÁ B. , WSÓL V. , LAMKA J.
Published: July 2005

Albendazole (ABZ) biotransformation was studied in vitro in liver microsomes of adult noncastrated male farm animals (ram, buck, bull and boar), castrated adult males (wether, billy and hog), and free living males (fallow buck, red deer stag, mouflon ram, roe buck and wild boar). Liver microsomal fractions were incubated with either ABZ or racemic albendazole sulphoxide (ABZSO). ABZ was extensively metabolized to the (+) and (−) enantiomers of ABZSO, whereas ABZSO underwent a slow oxidation to albendazole sulphone (ABZSO2) in all species. In all species both ABZSO enantiomers were detected. The chiral ratio, (+)‐ABZSO/(−)‐ABZSO, was greater than one in farm animals, mouflon and wild boar, and less than one in three species of deer. For total ABZ sulphoxidation, deer like species had lower values compared to the other species. Mouflon ram and ram had lower total sulphoxidation rates compared to wethers, as well as ABZ suphoxidation towards (+)‐ABZSO. No significant difference occurred comparing ABZSO formation in mouflon ram and ram, but ABZSO2 formation rate in mouflon ram was higher than in rams and wethers. Roe deer stag, fallow buck and red deer stag did not differ in both total‐ABZSO and (−)‐ABZSO synthesis rates and roe deer stag and fallow buck did not differ in synthesis rates of (+)‐ABZSO and ABZSO2. The bull differed from other species in all metabolites studied, except for red deer stag and boar in (−)‐ABZSO synthesis rate. The extent of ABZSO sulphonation to ABZSO2 in bull microsomes was more than twice that of other species.
Ototoxicity and tolerance assessment of a TrisEDTA and polyhexamethylene biguanide ear flush formulation in dogs
Authors: MILLS P. C. , AHLSTROM L. , WILSON W. J.
Published: July 2005

Clinically healthy mixed breed dogs (n = 20) were used to determine if a Tris (tromethamine)‐buffered test solution, Otinide®(Trademark of Dermcare‐Vet Pty‐Ltd, Australia), containing disodium ethylenediamine tetraacetic acid (EDTA; 1.21 g/L) and polyhexamethylene biguanide (PHMB; 0.22 g/L) caused ototoxicity or vestibular dysfunction. The dogs were randomly assigned to either a control group (group A,n = 10) receiving saline, or a treatment group (group B,n = 10) receiving the test solution. Phase 1 of the study consisted of applying 5.0 mL of saline to both ears of the control group (group A) and 5 mL of test solution to both ears of the test group (group B), for 21 days. A bilateral myringotomy was then performed on each dog under deep sedation. Phase 2 of the study then consisted of applying 2.0 mL of the saline to both ears of the control group (group A) and 2.0 mL of the test solution to both ears of the test group (group B), for 14 days. Throughout the study, dogs were examined for clinical health, and underwent otoscopic, vestibular and auditory examinations. The auditory examinations included brainstem auditory evoked potential (BAEP) threshold and supra‐threshold assessments using both click and 8 kHz tone burst stimuli. The absence of vestibular signs and effects on the BAEP attributable to the test solution suggested the test solution could be applied safely to dogs, including those with a damaged tympanic membrane.
The NusA:RNA polymerase ratio is increased at sites of rRNA synthesis in Bacillus subtilis
Authors: Davies Karen M. , Dedman Amy J. , van Horck Stephanie , Lewis Peter J.
Published: July 2005

Bacterial RNA polymerases (RNAPs) are capable of producing full‐length transcripts in the absence of additional factors using in vitro assays. However, in vivo RNAP can become stalled during the elongation phase of transcription due to the presence of various sequence motifs. Subsequently, a host of elongation factors are required to modulate the activity of RNAP. NusA, the most intensively studied elongation factor, plays a role in increasing RNAP pausing and termination. Conversely, it is also important in transcription of rRNA where it functions as an anti‐termination factor, helping to ensure only full‐length transcripts are produced. Here we show that NusA is closely associated with RNAP within the bacterial nucleoid and that it is preferentially recruited to sites of rRNA synthesis. In vivo and in vitro analyses indicate this results in a change in stoichiometry of NusA:RNAP from 1:1 to approximately 2:1 at the subcellular sites of rRNA synthesis. A model is presented showing how the ratio of NusA:RNAP could affect the activity of the elongation complex so that it functions as an anti‐terminator complex during rRNA synthesis.
Where asymmetry in gene expression originates
Authors: Barák Imrich , Wilkinson Anthony J.
Published: July 2005

A general problem in developmental biology concerns the process by which cells of one type divide to give dissimilar daughter cells. Even though these daughter cells may be genetically identical, they can differ morphologically and physiologically and have different fates. As one of the simplest differentiation processes, Bacillus subtilis sporulation represents an excellent model system for studying cell differentiation. Several decades of study of this process have provided insight into cell cycle regulation and development. This review summarizes important advances in our understanding of asymmetric gene expression during spore formation with an emphasis on developmental stages that lead to asymmetric septum formation and especially to activation of the first compartment‐specific sigma factor –σF.
The phage‐shock‐protein response
Authors: Darwin Andrew J.
Published: July 2005

The phage‐shock‐protein (Psp) system responds to extracytoplasmic stress that may reduce the energy status of the cell. It is conserved in many different bacteria and has been linked to several important phenotypes. Escherichia coli psp mutants have defects in maintenance of the proton‐motive force, protein export by the sec and tat pathways, survival in stationary phase at alkaline pH, and biofilm formation. Yersinia enterocolitica psp mutants cannot grow when the secretin component of a type III secretion system is mislocalized, and have a severe virulence defect in animals. A Salmonella enterica psp mutation exacerbates some phenotypes of an rpoE null mutant and the psp genes of S. enterica and Shigella flexneri are highly induced during macrophage infection. PspA, the most abundant of the Psp proteins, is required for most of the phenotypes associated with the Psp system. Therefore, PspA is probably an effector that may play a role in maintaining cytoplasmic membrane integrity and/or the proton‐motive force. However, PspA is not required for the ability to tolerate secretin mislocalization, which suggests an important physiological role for other Psp proteins. This article summarizes our current understanding of the Psp system: inducing signals, the underlying signal transduction mechanisms, the physiological roles it may play, and a genomic analysis of its conservation.
C‐di‐GMP: the dawning of a novel bacterial signalling system
Authors: Römling Ute , Gomelsky Mark , Galperin Michael Y.
Published: July 2005

Bis‐(3′‐5′)‐cyclic dimeric guanosine monophosphate (c‐di‐GMP) has come to the limelight as a result of the recent advances in microbial genomics and increased interest in multicellular microbial behaviour. Known for more than 15 years as an activator of cellulose synthase in Gluconacetobacter xylinus, c‐di‐GMP is emerging as a novel global second messenger in bacteria. The GGDEF and EAL domain proteins involved in c‐di‐GMP synthesis and degradation, respectively, are (almost) ubiquitous in bacterial genomes. These proteins affect cell differentiation and multicellular behaviour as well as interactions between the microorganisms and their eukaryotic hosts and other phenotypes. While the role of GGDEF and EAL domain proteins in bacterial physiology and behaviour has gained appreciation, and significant progress has been achieved in understanding the enzymology of c‐di‐GMP turnover, many questions regarding c‐di‐GMP‐dependent signalling remain unanswered. Among these, the key questions are the identity of targets of c‐di‐GMP action and mechanisms of c‐di‐GMP‐dependent regulation. This review discusses phylogenetic distribution of the c‐di‐GMP signalling pathway in bacteria, recent developments in biochemical and structural characterization of proteins involved in its metabolism, and biological processes affected by c‐di‐GMP. The accumulated data clearly indicate that a novel ubiquitous signalling system in bacteria has been discovered.
SpeB–Spi: a novel protease–inhibitor pair fromStreptococcus pyogenes
Authors: Kagawa Todd F. , O'Toole Paul W. , Cooney Jakki C.
Published: July 2005

This study presents evidence for a novel protease–protease inhibitor couple, SpeB–Spi, in the human pathogenStreptococcus pyogenes. The gene for the inhibitor Spi is located directly downstream of the gene for the streptococcal cysteine protease SpeB. Spi is 37% identical and 70% similar to the sequence of the SpeB propeptide, suggesting that Spi and the SpeB propeptide might bind to SpeB in an analogous manner. Secondary structure predictions and molecular modelling suggested that Spi would adopt a structure similar to the SpeB propeptide. Thespigene was co‐transcribed withspeBon the 1.7 knt and 2.2 knt transcripts previously identified forspeB. The Spi protein was purified by SpeB‐affinity chromatography from theS. pyogenescytoplasm. Recombinant Spi was produced and purified, and shown to bind to SpeB and to inhibit its protease activity. Although a similar genetic arrangement of protease and inhibitor is present in staphylococci, this is the first example of an inhibitor molecule that is a structural homologue of the cognate propeptide, and which is genetically linked to the protease gene. Thus, this represents a novel system whereby bacteria may control the intracellular activity of their proteases.
Bacillus anthracis CapD, belonging to the γ‐glutamyltranspeptidase family, is required for the covalent anchoring of capsule to peptidoglycan
Authors: Candela Thomas , Fouet Agnès
Published: July 2005

Several examples of bacterial surface‐structure anchoring have been described, but they do not include polyglutamate capsule. Bacillus anthracis capsule, which is composed only of poly‐γ‐ d‐glutamate, is one of the two major virulence factors of the bacterium. We analysed its anchoring. We report that the polyglutamate is anchored directly to the peptidoglycan and that the bond is covalent. We constructed a capD mutant strain, capD being the fourth gene of the capsule biosynthetic operon. The mutant bacilli are surrounded by polyglutamate material that is not covalently anchored. Thus, CapD is required for the covalent anchoring of polyglutamate to the peptidoglycan. Sequence similarities suggest that CapD is a γ‐glutamyltranspeptidase. Furthermore, CapD is cleaved at the γ‐glutamyltranspeptidase consensus cleavage site, and the two subunits remain associated, as necessary for γ‐glutamyltranspeptidase activity. Other Gram‐positive γ‐glutamyltranspeptidases are secreted, but CapD is located at the Bacillus surface, associated both with the membrane and the peptidoglycan. Polyglutamate is hydrolysed by CapD indicating that it is a CapD substrate. We suggest that CapD catalyses the capsule anchoring reaction. Interestingly, the CapD– strain is far less virulent than the parental strain.
DNA polymerase I acts in translesion synthesis mediated by the Y‐polymerases in Bacillus subtilis
Authors: Duigou Stéphane , Ehrlich S. Dusko , Noirot Philippe , Noirot‐Gros Marie‐Françoise
Published: July 2005

Translesion synthesis (TLS) across damaged DNA bases is most often carried out by the ubiquitous error‐prone DNA polymerases of the Y‐family. Bacillus subtilis encodes two Y‐polymerases, Pol Y1 and Pol Y2, that mediate TLS resulting in spontaneous and ultraviolet light (UV)‐induced mutagenesis respectively. Here we show that TLS is a bipartite dual polymerase process in B. subtilis, involving not only the Y‐polymerases but also the A‐family polymerase, DNA polymerase I (Pol I). Both the spontaneous and the UV‐induced mutagenesis are abolished in Pol I mutants affected solely in the polymerase catalytic site. Physical interactions between Pol I and either of the Pol Y polymerases, as well as formation of a ternary complex between Pol Y1, Pol I and the β‐clamp, were detected by yeast two‐ and three‐hybrid assays, supporting the model of a functional coupling between the A‐ and Y‐family polymerases in TLS. We suggest that the Pol Y carries the synthesis across the lesion, and Pol I takes over to extend the synthesis until the functional replisome resumes replication. This key role of Pol I in TLS uncovers a new function of the A‐family DNA polymerases.
MsmR, a specific positive regulator of the Streptococcus pyogenes FCT pathogenicity region and cytolysin‐mediated translocation system genes
Authors: Nakata Masanobu , Podbielski Andreas , Kreikemeyer Bernd
Published: July 2005

As a prerequisite for colonization or causing local infections, Streptococcus pyogenes (group A streptococci, GAS) need to specifically adhere to eukaryotic cell surfaces. Predominantly responsible adhesin genes are contained in a genotype‐specific pattern within the FCT region of the GAS genome. In this study, MsmR, belonging to AraC/XylS type transcriptional regulators, was identified in the FCT region as a positive regulator of the major fibronectin‐binding adhesin protein F2 in a serotype M49 strain. Compared with the wild‐type strain, the msmR mutant showed reduced binding to immobilized fibronectin and decreased adherence to and internalization into human pharyngeal epithelial cells. These results suggested that altered levels of fibronectin‐binding proteins in the mutant affect eukaryotic cell attachment and internalization. Complete transcriptome and reporter fusion assay data revealed that MsmR positively regulates FCT region genes including Nra and cytolysin‐mediated translocation system genes. Consistent with the genetic data, the mutant showed attenuated streptolysin O activity and eukaryotic cell cytotoxity. Direct binding of recombinant MsmR to nga, nra/cpa and prtF2 promoter regions was confirmed by EMSA assays. As prior analysis demonstrated the Nra regulator negatively affects gene expression from the FCT region, MsmR and Nra appear to adversely control crucial virulence factor expression in GAS and thus contribute to a fine‐tuned balance between local destructive process and metastatic spreading of the bacteria.
HilD, HilC and RtsA constitute a feed forward loop that controls expression of the SPI1 type three secretion system regulator hilA in Salmonella enterica serovar Typhimurium
Authors: Ellermeier Craig D. , Ellermeier Jeremy R. , Slauch James M.
Published: July 2005

Salmonella enterica serovar Typhimurium invades intestinal epithelial cells using a type three secretion system (TTSS) encoded on Salmonella Pathogenicity Island 1 (SPI1). The SPI1 TTSS injects effector proteins into the cytosol of host cells where they promote actin rearrangement and engulfment of the bacteria. We previously identified RtsA, an AraC‐like protein similar to the known HilC and HilD regulatory proteins. Like HilC and HilD, RtsA activates expression of SPI1 genes by binding upstream of the master regulatory gene hilA to induce its expression. HilA activates the SPI1 TTSS structural genes. Here we present evidence that hilA expression, and hence the SPI1 TTSS, is controlled by a feedforward regulatory loop. We demonstrate that HilC, HilD and RtsA are each capable of independently inducing expression of the hilC, hilD and rtsA genes, and that each can independently activate hilA. Using competition assays in vivo, we show that each of the hilA regulators contribute to SPI1 induction in the intestine. Of the three, HilD has a predominant role, but apparently does not act alone either in vivo or in vitro to sufficiently activate SPI1. The two‐component regulatory systems, SirA/BarA and OmpR/EnvZ, function through HilD, thus inducing hilC, rtsA and hilA. However, the two‐component systems are not responsible for environmental regulation of SPI1. Rather, we show that ‘SPI1 inducing conditions’ cause independent activation of the rtsA, hilC and hilD genes in the absence of known regulators. Our model of SPI1 regulation provides a framework for future studies aimed at understanding this complicated regulatory network.
Post‐Flowering Photoperiod Effects on Reproductive Development and Agronomic Traits of Long‐Day and Short‐Day Crops
Authors: Han T. , Wu C. , Mentreddy R. S. , Zhao J. , Xu X. , Gai J.
Published: July 2005

Pre‐flowering photoperiod effects on floral initiation, flowering time and yield components of various crops have been well studied, but the post‐flowering photoperiod effects on major field crops are not clearly understood. A controlled environment study was carried out using six long‐day (LD) crops, flax, sugar beet, broad bean, triticale, wheat, and rapeseed, and seven short‐day (SD) crops including Adzuki bean, potato, rice, peanut, mungbean, cotton and corn with a major objective of evaluating the post‐flowering photoperiod effects on their reproductive development and yield components. There were significant inter‐ and intra‐specific differences in their response to post‐flowering photoperiod treatments. The effects of short days on LD crops were similar to LD effects on SD crops. The post‐flowering duration was prolonged by short photoperiod in LD crops and long photoperiod in SD crops. There was, however, significant genotypic variation within a species for such effects. The post‐flowering LD treatment caused abscission of flowers and pods and the resumption of vegetative growth in Adzuki bean. The post‐flowering LD treatment also delayed the shoot senescence of one of the two potato varieties and decreased the number of tubers per plant in both varieties. The LD treatment delayed maturation of rice and mungbean, and decreased seed yield and 100‐seed weight of peanut, although the shoot senescence of peanut was not apparently affected. Rapeseed, wheat, cotton and corn genotypes in this study did not show any sensitivity to post‐flowering photoperiod. In triticale (an LD crop) exposure to short photoperiod post‐flowering increased the number of spikes per plant perhaps due to a greater assimilate accumulation over a longer duration. The results from the current study as well as those from our previous experiments suggest that post‐flowering photoperiod responses do exist in diverse field crops, and that there are strong genotypic differences in sensitivity and magnitude of response to post‐flowering photoperiod. Photoperiod after flowering substantially regulates the source/sink relationship, and promotes partitioning and accumulation of assimilates to storage organs of crops when it favours the reproductive development of crops.
Barley Autotoxicity as Influenced by Varietal and Seasonal Variation
Authors: Oueslati O. , Ben‐Hammouda M. , Ghorbal M. H. , Guezzah M. , Kremer R. J.
Published: July 2005

Barley (Hordeum vulgare L.) is widely cultivated in the semi‐arid region of Tunisia for grain production and grazing, which often occurs during the same season. We previously demonstrated autotoxic effects of barley among varieties. The present study was conducted to test the effects of barley variety and seasonal variation on the expression of autotoxicity by barley. Four barley varieties were grown in a field experiment over three growing seasons (1999–2000, 2000–01, 2001–02). In the laboratory, germination and seedling growth bioassays were used to assess autotoxicity potential of field‐harvested barley. Barley autotoxicity was fully expressed based on inhibition of radicle growth detected in seedling bioassays. Stems were often the most allelopathic plant component. Allelopathic activity of the barley varieties differed across growing seasons suggesting the influence of a seasonal effect due to the extent of water deficit during the dry season and monthly rainfall variability. The results suggest that when planning to integrate barley within cropping sequences, barley producers should carefully select appropriate barley varieties to minimize autotoxicity, which can be more severe under drought conditions.
Effects of Seed Treatment and Foliar Fungicides on Helminthosporium Leaf Blight and on Performance of Wheat in Warmer Growing Conditions
Authors: Sharma‐Poudyal D. , Duveiller E. , Sharma R. C.
Published: July 2005

As the wheat (Triticum aestivum L.) cultivars of south Asia are susceptible to Helminthosporium leaf blight (HLB) caused by Cochliobolus sativus and Pyrenophora tritici‐repentis, chemical control through seed treatment and foliar fungicides could increase yields. A field study was conducted in 2002 and 2003 to determine the effect of seed treatment and foliar fungicides on disease and performance of wheat. Presown seed infection by the pathogen was determined in a laboratory test. Seed was treated with Vitavax® 200B, Bavistin® and Simonis carbendazim in 2002, and Areestin® instead of Simonis carbendazim in 2003. One and two foliar sprays with Opus®, Allegro®, Horizon® and Tilt® were tested, along with a control treatment. Cochliobolus sativus was isolated from 8 and 34% presown seeds in 2002 and 2003, respectively, and no P. tritici‐repentis was found. Seed treatments were not equally effective: Vitavax® 200B increased germination by up to 43% in both years and reduced seedling infection by C. sativus in 2003. The foliar fungicides reduced HLB severity and increased grain yield. Compared with the control, the highest reduction in area under disease progress curve (AUDPC) was 53% in 2002 and 63% in 2003. The highest increase in grain yield over the control due to fungicide spray was 38% in 2002 and 83% in 2003. Grain infection in 2002 (39%) and 2003 (70%) in the control plot was reduced to 16 and 24%, respectively, thanks to the application of foliar fungicides. Two fungicide sprays in most cases did not reduce the AUDPC and grain infection and increased grain yield any more than did one spray. The results show that seed treatment was not effective in reducing HLB severity and increasing grain yield, but foliar fungicide spray was. The cost–benefit analysis shows that one spray could be cost‐effective for all four fungicides when a susceptible cultivar is planted under high HLB severity.
Peroxidase and Pectin Methylesterase Activities in Cocoyam (Xanthosoma sagittifolium L. Schott) Roots upon Pythium myriotylum Inoculation
Authors: Boudjeko T. , Omokolo N. A. , Driouich A. , Balangé A. P.
Published: July 2005

Cocoyam (Xanthosoma sagittifolium) is an important source of energy food for humid and semihumid tropic populations and consists of three cvs distinguished by the colour of their flesh, their productivity and their root rot disease scores: one sensitive (white), one intermediate (red) and one resistant (yellow). Changes in peroxidase (POD; EC 1.11.1.7) and pectin methylesterase (PME; EC 3.1.1.11) activities from roots of the three cvs were examined by isoelectrofocusing (IEF), polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulphate (SDS)‐PAGE upon inoculation with Pythium myriotylum. The evaluation of total POD activity shows the existence of a correlation between the sensitivity to P. myriotylum and POD activity. After 2 days of inoculation, POD activity of yellow cv. increased by 41.5%, while in the white and the red cvs the increase was only 13.4% and 7.5% respectively. In the soluble fractions of the resistant cv., the patterns of POD isozymes showed three new bands (Rf = 0.25; 0.38 and 0.85) and in ionically bound fraction, a new acidic (Rf = 0.2) specifically in inoculated root. The study of substrate specificity of POD with chlorogenic acid (C‐POD), ferulic acid (F‐POD) and indole acetic acid (IAA‐POD) showed an induction of C‐POD and F‐POD and a decrease in IAA‐POD in cocoyam roots after inoculation with P. myriotylum. Constitutively, ionically bound C‐POD and F‐POD activities were higher in roots of the yellow (11.6 and 11.7 EU/g Fw) than in those of the red (5.3 and 7.0 EU/g Fw) and the white (2.3 and 4.2 EU/g Fw) cvs. In addition, isoelectric‐focusing analysis of PME revealed an alteration of their profile correlated with inoculation. After inoculation, the appearance of a strong (pI: 9.7) and low (pI: 7.6) PME activities in the roots of yellow cv. were detected. Our findings suggest that POD and PME might be involved in the defence mechanism of cocoyam against P. myriotylum.
Occurrence in Elx, SE Spain of Inflorescence Rot Disease of Date Palms Caused by Mauginiella scaettae
Authors: Abdullah S. K. , Asensio L. , Monfort E. , Gomez‐Vidal S. , Palma‐Guerrero J. , Salinas J. , Lopez‐Llorca L. V. , Jansson H.‐B. , Guarro J.
Published: July 2005

Fungal inflorescence rot of date palms, caused by Mauginiella scaettae, was detected at all four sites surveyed in Elx, SE Spain. There was a higher incidence of the disease in male than in female inflorescences. The pathogen responsible for the disease was isolated and identified as M. scaettae. Sequencing of the internal transcribed spacer (ITS) region of this fungus demonstrated that it is close to Phaeosphaeria.
Determination of Trichothecene Chemotypes of Fusarium graminearum Strains Isolated in Hungary
Authors: Szécsi Á. , Bartók T. , Varga M. , Magyar D. , Mesterházy Á.
Published: July 2005

A total of 42 strains of Fusarium graminearum isolated from cereals, maize, grasses and air were screened for their ability to produce 8‐ketotrichothecenes [deoxynivalenol (DON), 3‐acetyldeoxynivalenol (ADON), 15‐ADON, nivalenol (NIV)]. The isolates were grown on the solid substrate of rice grains in the dark at 25 and 10°C for 28 days. Toxin analyses were made by gas chromatography mass spectrometry (GC‐MS) technique. The GC‐MS was more suitable for qualitative and quantitative determination of acetyl‐DONs, than high‐performance liquid chromatographic (HPLC) technique. Of the 42 F. graminearum isolates, 39 produced DON, 34 produced both 3‐ and 15‐ADON and one produced DON‐NIV. The quantity of DON varied with isolates (46–6840 mg/kg). Our results suggest that strains of F. graminearum prevailing in Hungarian cereal‐ and maize‐growing regions belong to DON chemotype.
An In vitro Study on the Postinfection Activities of Hydrated Lime and Lime Sulphur against Apple Scab (Venturia inaequalis)
Authors: Montag J. , Schreiber L. , Schönherr J.
Published: July 2005

The activities of hydrated lime and lime sulphur to stop infections of apple scab (Venturia inaequalis) were evaluated at 20°C using an in vitro test system based on isolated cuticles and scab conidia. Treatments were applied 24 or 48 h after inoculation that is 16 or 40 h after a predicted infection period, respectively. Efficacy of the postinfection treatments was assessed 72 h after inoculation by counting living primary stromata, which fluoresced brightly green when stained with fluorescein diacetate (FDA). A suspension of hydrated lime (5 g/l) as well as lime sulphur (1.5%) applied 16 h after infection killed early infection structures and stopped further development. Lime sulphur reduced the percentage of penetration to below 10% even with treatments 40 h after infection. The activity of hydrated lime is due to its alkaline pH of 12.45. Suspensions of calcium carbonate (6.75 g/l) showed no effect on percentage of penetration. Up to pH 12.0 effects of potassium hydroxide solutions on vitality of germinated conidia and percentage of penetration were weak. Values of pH 12.4 or higher were necessary to kill germinated conidia of V. inaequalis and their primary penetration structures. At pH 12.4 activity of KOH was comparable with the effect of hydrated lime. It is argued that the high pH disrupts the spore membranes. This is supported by the fact that dead spores and germ tubes did not fluoresce with FDA, which requires integrity of the membranes. For an individual spore the disruption of the spore membrane is an all‐or‐nothing event.
Immunohistochemical Detection of Parainfluenza Type 3 Virus Antigens in Paraffin Sections of Pneumonic Caprine Lungs
Authors: Yener Z. , Sağlam Y. S. , Timurkaan N. , Ilhan F.
Published: July 2005

Pneumonia is a leading cause of loss to ruminants throughout the world. Parainfluenza type‐3 virus (PI‐3) is one of the most important respiratory pathogens of bovine and ovine. In this study, prevalence of PI‐3 virus infection as causative agent of pneumonia in goats was investigated. For this purpose, a total of 1505 goat lungs slaughtered in Bitlis and Van slaughterhouses were grossly examined and pneumonia was detected in 74 cases (4.91%). Lesions were more frequently encountered in anteroventral lobes than caudal lobes. With the exception of verminous pneumonia observed in 32 cases, immunohistochemical examinations were performed on 42 pneumonic lungs. Formalin‐fixed and paraffin‐embedded lung tissue samples were immunohistochemically stained by the avidin–biotin–peroxidase complex procedure using polyclonal antibodies to detect PI‐3 viral antigens. The presence of PI‐3 viral antigens was detected in 28 (66.6%) of 42 pneumonic lungs. Viral antigens were found most frequently in the cytoplasm of bronchiolar epithelial cells, type II pneumocytes, and less frequently in the epithelial cells of bronchial glands, syncytial cells, alveolar macrophages, and lymphocytes and plasma cells. In conclusion, it was found that there was a close relationship between the pneumonia in goats and the presence of PI‐3 viral antigens. Incidence of PI‐3 virus in pneumonic lungs of goats was detected to be very high in the present study performed in the region of Bitlis and Van, Turkey.