bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic discontinuities and disequilibria in recently established populations of the plant pathogenic fungus Mycosphaerella fijiensis
Authors: HALKETT F. , COSTE D. , RIVAS PLATERO G. G. , ZAPATER M. F. , ABADIE C. , CARLIER J.
Published: August 2010

Dispersal processes of fungal plant pathogens can be inferred from analysis of spatial genetic structures resulting from recent range expansion. The relative importance of long‐distance dispersal (LDD) events vs. gradual dispersal in shaping population structures depends on the geographical scale considered. The fungus Mycosphaerella fijiensis, pathogenic on banana, is an example of a recent worldwide epidemic. Founder effects in this species were detected at both global and continental scale, suggesting stochastic spread of the disease through LDD events. In this study, we analysed the structure of M. fijiensis populations in two recently (∼1979–1980) colonized areas in Costa Rica and Cameroon. Isolates collected in 10–15 sites distributed along a ∼250‐ to 300‐ km‐long transect in each country were analysed using 19 microsatellite markers. We detected low‐to‐moderate genetic differentiation among populations in both countries and isolation by distance in Cameroon. Combined with historical data, these observations suggest continuous range expansion at the scale of banana‐production area through gradual dispersal of spores. However, both countries displayed specific additional signatures of colonization: a sharp discontinuity in gene frequencies was observed along the Cameroon transect, while the Costa Rican populations seemed not yet to have reached genetic equilibrium. These differences in the genetic characteristics of M. fijiensis populations in two recently colonized areas are discussed in the light of historical data on disease spread and ecological data on landscape features.
The BCCT family of carriers: from physiology to crystal structure
Authors: Ziegler Christine , Bremer Erhard , Krämer Reinhard
Published: August 2010

Increases in the environmental osmolarity are key determinants for the growth of microorganisms. To ensure a physiologically acceptable level of cellular hydration and turgor at high osmolarity, many bacteria accumulate compatible solutes. Osmotically controlled uptake systems allow the scavenging of these compounds from scarce environmental sources as effective osmoprotectants. A number of these systems belong to the BCCT family (betaine‐choline‐carnitine‐transporter), sodium‐ or proton‐coupled transporters (e.g. BetP and BetT respectively) that are ubiquitous in microorganisms. The BCCT family also contains CaiT, an l‐carnitine/γ‐butyrobetaine antiporter that is not involved in osmotic stress responses. The glycine betaine transporter BetP from Corynebacterium glutamicum is a representative for osmoregulated symporters of the BCCT family and functions both as an osmosensor and osmoregulator. The crystal structure of BetP in an occluded conformation in complex with its substrate glycine betaine and two crystal structures of CaiT in an inward‐facing open conformation in complex with l‐carnitine and γ‐butyrobetaine were reported recently. These structures and the wealth of biochemical data on the activity control of BetP in response to osmotic stress enable a correlation between the sensing of osmotic stress by a transporter protein with the ensuing regulation of transport activity. Molecular determinants governing the high‐affinity binding of the compatible solutes by BetP and CaiT, the coupling in symporters and antiporters, and the osmoregulatory properties are discussed in detail for BetP and various BCCT carriers.
ABI domain‐containing proteins contribute to surface protein display and cell division in Staphylococcus aureus
Authors: Frankel Matthew B. , Wojcik Brandon M. , DeDent Andrea C. , Missiakas Dominique M. , Schneewind Olaf
Published: August 2010

The human pathogen Staphyloccocus aureus requires cell wall anchored surface proteins to cause disease. During cell division, surface proteins with YSIRK signal peptides are secreted into the cross‐wall, a layer of newly synthesized peptidoglycan between separating daughter cells. The molecular determinants for the trafficking of surface proteins are, however, still unknown. We screened mutants with non‐redundant transposon insertions by fluorescence‐activated cell sorting for reduced deposition of protein A (SpA) into the staphylococcal envelope. Three mutants, each of which harboured transposon insertions in genes for transmembrane proteins, displayed greatly reduced envelope abundance of SpA and surface proteins with YSIRK signal peptides. Characterization of the corresponding mutations identified three transmembrane proteins with abortive infectivity (ABI) domains, elements first described in lactococci for their role in phage exclusion. Mutations in genes for ABI domain proteins, designated spdA, spdB and spdC (surface protein display), diminish the expression of surface proteins with YSIRK signal peptides, but not of precursor proteins with conventional signal peptides. spdA, spdB and spdC mutants display an increase in the thickness of cross‐walls and in the relative abundance of staphylococci with cross‐walls, suggesting that spd mutations may represent a possible link between staphylococcal cell division and protein secretion.
Recognition of heptameric seed sequence underlies multi‐target regulation by RybB small RNA in Salmonella enterica
Authors: Balbontín Roberto , Fiorini Francesca , Figueroa‐Bossi Nara , Casadesús Josep , Bossi Lionello
Published: August 2010

Prokaryotic regulatory small RNAs act by a conserved mechanism and yet display a stunning structural variability. In the present study, we used mutational analysis to dissect the functional anatomy of RybB, a σE‐dependent sRNA that regulates the synthesis of major porins in Escherichia coli and Salmonella. Mutations in the chromosomal rybB locus that altered the expression of an ompC–lac fusion were identified. Some of the mutations cluster within a seven‐nucleotide segment at the 5′ end of the sRNA and affect its ability to pair with a sequence 40 nucleotides upstream from ompC translation start site. Other mutations map near the 3′ end of RybB, destabilizing the sRNA or altering its binding to Hfq. The 5′ end of RybB is also involved in ompD regulation. In this case, the sRNA can choose between two mutually exclusive pairing sites within the translated portion of the mRNA. Some of the RybB 5′ end mutations affect the choice between the two sites, resulting in regulatory responses that diverge from those observed in ompC. Further analysis of RybB target specificity identified chiP (ybfM), a gene encoding an inducible chitoporin, as an additional member of the RybB regulon. Altogether, our results indicate that an heptameric ‘seed’ sequence is sufficient to confer susceptibility to RybB regulation.
Multiple metabolic signals influence GAL gene activation by modulating the interaction of Gal80p with the transcriptional activator Gal4p
Authors: Li Yan , Chen Guanjun , Liu Weifeng
Published: August 2010

Transcriptional status of the genes needed for galactose utilization in Saccharomyces cerevisiae is controlled by the interplay between the prototypical transcriptional activator Gal4p and the inhibitor protein Gal80p. Relief of the inhibition from Gal4p requires the interaction between Gal80p and the galactokinase paralog, Gal3p. Here, we present evidence that decrease in the intracellular levels of ATP or NADP(H) impairs the GAL gene expression. All these induction defects are rescued by overproducing Gal3p or producing Gal4p mutants with reduced interaction with Gal80p. We further demonstrate that removal of Gal80p from the GAL gene promoter is impaired in these mutants, and that NADP(H) cooperates with Gal3p in causing the dissociation of Gal80p from the in vitro preformed DNA‐bound Gal80p–Gal4p complex. We also show that Gal80p is only partially removed from the GAL gene promoter in a mitochondria fusion‐deficient mutant where the cotranscriptional mRNA processing is crippled. The efficient dissociation is restored by Gal4p mutants with altered interaction with Gal80p and is correlated with the recovered GAL gene expression. These results indicate that multiple metabolic signals exist to facilitate the efficient and appropriate dissociation of Gal80p from Gal4p by Gal3p to achieve the fully active state of Gal4p in the nucleus.
Membrane association of PspA depends on activation of the phage‐shock‐protein response in Yersinia enterocolitica
Authors: Yamaguchi Saori , Gueguen Erwan , Horstman N. Kaye , Darwin Andrew J.
Published: August 2010

Regulation of the bacterial phage‐shock‐protein (Psp) system involves communication between integral (PspBC) and peripheral (PspA) cytoplasmic membrane proteins and a soluble transcriptional activator (PspF). In this study protein subcellular localization studies were used to distinguish between spatial models for this putative signal transduction pathway in Yersinia enterocolitica. In non‐inducing conditions PspA and PspF were almost exclusively in the soluble fraction, consistent with them forming an inhibitory complex in the cytoplasm. However, upon induction PspA, but not PspF, mainly associated with the membrane fraction. This membrane association was dependent on PspBC but independent of increased PspA concentration. Analysis of psp null, overexpression and altered function mutants further supported a model where PspA is predominantly membrane associated only when the system is induced. Activation of the Psp system normally leads to a large increase in PspA concentration and we found that this provided a second mechanism for its membrane association, which did not require PspBC. These data suggest that basal PspFABC protein levels constitute a regulatory switch that moves some PspA to the membrane when an inducing trigger is encountered. Once this switch is activated PspA concentration increases, which might then allow it to directly contact the membrane for its physiological function.
Repeat regions R1 and R2 in the P97 paralogue Mhp271 ofMycoplasma hyopneumoniaebind heparin, fibronectin and porcine cilia
Authors: Deutscher Ania T. , Jenkins Cheryl , Minion F. Chris , Seymour Lisa M. , Padula Matthew P. , Dixon Nicholas E. , Walker Mark J. , Djordjevic Steven P.
Published: August 2010

Mycoplasma hyopneumoniae, the causative agent of porcine enzootic pneumonia, adheres to ciliated respiratory epithelia resulting in ciliostasis and epithelial cell death. The cilium adhesin P97 (Mhp183) contains two repeat regions, designated R1 and R2, that play key roles in adherence. Eight pentapeptide repeats in R1 are sufficient to bind porcine cilia; however, both R1 and R2 are needed to bind heparin. Mhp271, a paralogue of P97, is the only otherM. hyopneumoniaeprotein to contain both R1 and R2 repeats. These repeats are arranged as a set of three pentapeptide repeats (designated R1A271), two decapeptide repeats (designated R2271), and a second set of six pentapeptide repeats (designated R1B271). To determine their function, recombinant proteins containing R1A271(F1271) and R2271‐R1B271(F2271) were constructed and used inin vitrobinding assays. F2271, but not F1271, bound heparin (KD = 8.1 ± 0.4 nM), fibronectin (KD = 174 ± 13 nM) and porcine cilia. Pre‐incubation of F2271with 100 µM heparin blocked cilium binding by ∼69%. Cell surface shaving with trypsin combined with two‐dimensional liquid chromatography coupled to tandem mass spectrometry analysis identified Mhp271 as surface‐exposed. Our data suggest that both R1 and R2 in Mhp271 are involved in binding to host molecules.
Environmental control of phosphorylation pathways in a branched two‐component system
Authors: López‐Redondo Maria Luisa , Moronta Felix , Salinas Paloma , Espinosa Javier , Cantos Raquel , Dixon Ray , Marina Alberto , Contreras Asunción
Published: August 2010

NblS, the most conserved histidine kinase in cyanobacteria, regulates photosynthesis and acclimatization to a variety of environmental conditions. We used in silico, in vivo and in vitro approaches to identify RpaB and SrrA as the cognate response regulators of NblS and to characterize relevant interactions between components of this signalling system. While genetic analysis showed the importance of the NblS to RpaB phosphorylation branch for culture viability in Synechococcus elongatus PCC 7942, in vitro assays indicated a strong preference for NblS to phosphorylate SrrA. This apparent discrepancy can be explained by environmental insulation of the RpaB pathway, achieved by RpaB‐dependent repression of srrA under standard, low light culture conditions. After a strong but transient increase in srrA expression upon high light exposure, negative regulation of srrA and other high light inducible genes takes place, suggesting cooperation between pathways under environmental conditions in which both RpaB and SrrA are present. Complex regulatory interactions between RpaB and SrrA, two response regulators with a common evolutionary origin that are controlled by a single histidine kinase, are thus emerging. Our results provide a paradigm for regulatory interactions between response regulators in a branched two‐component system.
Complete resolution of psoriasis vulgaris after excision of thyroid cancer
Authors: Kano Yoko , Chiba Masako , Yagita Akikuni , Shiohara Tetsuo
Published: August 2010

A 61‐year‐old woman was seen with a 1‐month history of a widespread eruption over the trunk and extremities. She also had an asymptomatic tumor in the neck that had developed 8 years earlier. Examination revealed generalized, erythematous scaling plaques over the trunk, arms, and extremities (Fig. 1). An ultrasound and radioisotope scan of the neck disclosed a soft tissue mass compatible with thyroid carcinoma.

Laboratory tests showed a white cell count of 9.8X109/L, and triiodothyronine, thyroxin, and calcium levels within the normal range. The thyroid‐stimulating hormone (TSH) level was 6.3 μIU/mL (normal range 0.33–3.6 μIU/mL), and thyroglobulin was 320 μg/mL (normal range 14–31 μg/mL).

A skin biopsy specimen from the upper portion of the arm showed hyperkeratosis with focal parakeratosis and elongation of the rete ridges. The dermis showed mild papillary edema and perivascular lymphocytic infiltration compatible with psoriasis vulgaris. After the biopsy, ampicillin, 1000 mg daily, was administered for 21 days; however, the lesions were unchanged. The patient was then operated on with excision of the thyroid cancer and the regional lymph nodes. Histopathologic examination disclosed an adenocarcinoma of the thyroid; the lymph nodes were infiltrated by tumor cells. After the operation, cefazolin, 2000 mg daily, was given for 9 days. At 2 weeks postoperatively, the lesions began to subside without any dermatologic treatment and then resolved completely within 1 month of the operation (Fig. 2). Three weeks after the excision of the tumor, the patient started to receive levothyroxine sodium (T4), 0.1 mg daily, to compensate for low thyroid hormone production. Within the second postoperative month, TSH, triiodothyronine, and thyroglobulin returned to normal. After excision of the carcinoma, her psoriatic lesions, remained in remission for an additional 5 months without any dermatologic treatment.
Immediate and 5‐year cumulative outcome after paediatric intensive care in Sweden
Authors: GULLBERG N. , KALZÉN H. , LUHR O. , GÖTHBERG S. , WINSÖ O. , MARKSTRÖm A. , OLSSON A.‐K. , FROSTELL C. ,   SCANDINAVIAN CRITICAL CARE TRIALS GROUP
Published: August 2010

Background: Little has been reported about intensive care of children in Sweden. The aims of this study are to (I) assess the number of admissions, types of diagnoses and length‐of‐stay (LOS) for all Swedish children admitted to intensive care during the years 1998–2001, and compare paediatric intensive care units (PICUs) with other intensive care units (adult ICUs) (II) assess immediate (ICU) and cumulative 5‐year mortality and (III) determine the actual consumption of paediatric intensive care for the defined age group in Sweden.

Methods: Children between 6 months and 16 years of age admitted to intensive care in Sweden were included in a national multicentre, ambidirectional cohort study. In PICUs, data were also collected for infants aged 1–6 months. Survival data were retrieved from the National Files of Registration, 5 years after admission.

Results: Eight‐thousand sixty‐three admissions for a total of 6661 patients were identified, corresponding to an admission rate of 1.59/1000 children per year. Median LOS was 1 day. ICU mortality was 2.1% and cumulative 5‐year mortality rate was 5.6%. Forty‐four per cent of all admissions were to a PICU.

Conclusions: This study has shown that Sweden has a low immediate ICU mortality, similar in adult ICU and PICU. Patients discharged alive from an ICU had a 20‐fold increased mortality risk, compared with a control cohort for the 5‐year period. Less than half of the paediatric patients admitted for intensive care in Sweden were cared for in a PICU. Studies are needed to evaluate whether a centralization of paediatric intensive care in Sweden would be beneficial to the paediatric population.
The effects of sheep grazing on invertebrate numbers and biomass in unfertilized natural pastures of the New England Tablelands (NSW)
Authors: KING KATHLEEN L. , HUTCHINSON KEITH J.
Published: August 2010

Invertebrate components of natural pastures which were grazed continuously by sheep at three stocking intensities, were sampled each season for more than two years. Grazing resulted in a significant reduction in abundance of litter and topsoil micro‐arthropods. Two samplings for nematodes and enchytraeids showed similar reductions with grazing. Grazing effects on the vertical distribution of mesofauna were not consistent but all sites had greatest numbers in the 0 – 5 cm topmost soil layer. Fresh biomass of large soil and litter dwelling invertebrates also declined with grazing, with proportionally greater reductions occurring for litter animals. Changes in invertebrate populations were associated with changes in living space, microclimate and food supply. Populations of invertebrates on natural pastures were about one‐third those found on previously studied sown, fertilized pastures at Armidale.
Annuals with transient seed banks: the population biology of indigenous Sorghum species of tropical north‐west Australia
Authors: ANDREW MARTIN H. , MOTT JOHN J.
Published: August 2010

Indigenous Sorghum species are a prominent feature of the seasonally‐dry tropics of north‐west Australia. Studies of the dormancy characteristics of these species were undertaken, and measurements of seedling emergence, of plant survival, growth and reproductive success, and of seed bank changes were made for one Sorghum intrans population and for three S. stipoideum populations over two growing seasons.

On wetting, 90% of the non‐dormant, viable seeds of nil species germinated within five days. The temperature range for optimal germination was 25 ‐ 35°C, and germination declined with decreasing water potential. The seeds of all species had high innate dormancy at seedfall, and this was broken down over the ensuing dry season.

For S. intrans and S. stipoideum height and tiller number increased steadily after emergence up to the time of floral initiation, which occurred simultaneously for primary tillers within each population. Most vegetative tillers died after this leaving a single reproductive culm which rapidly elongated to reach 1 – 4 mat maturity, depending on site and season.

Seedfall occurred over a short, c. two‐week period before the rainy season had finished. Seeds were dispersed within 2 m of the parent plant. Seeds were buried to less than 2 cm by the screwing action of their hygroscopically‐active awns.

All these annual Sorghum species appear to have transient seedbanks, formed at seedfall near the end of one rainy season and exhausted by germination following the first rains of the next annual rainy season. We suggest that S. intrans and S. stipoideum persist despite this feature because they mature at the earliest time that the rainy season has been known to end in their respective localities. Persistence is further aided by adaptations which enable individuals to survive the unpredictable short droughts which occur while they are emerging and growing.

S. intrans and S. stipoideum have low fecundity (mean ≃ 8 viable seeds per individual) and high survivorship. They fit Watkinson's (1981) schema relating fecundity to survival for annuals with transient seed banks.
Suburban development and change in vegetation nutritional status
Authors: LAMBERT MARCIA J. , TURNER JOHN
Published: August 2010

In a study of species presence/absence and soil properties in bushland around northern Sydney, Clements (1983) found that species groupings were related to total soil phosphorus. This report presents analysis of foliage nutrient concentrations in species within these groupings. The highest concentrations of phosphorus, calcium, magnesium and potassium occurred in the suburban/disturbed group. The lowest overall concentrations were found in foliage from species in the dry sclerophyll communities. Mean foliage phosphorus was 0.099%, 0.125% and 0.042% for wet sclerophyll, disturbed and dry sclerophyll groups, respectively. Exotic species, particularly in disturbed environments, had the highest foliage nutrient concentrations. Results presented here showed that foliage nutrient concentrations are consistent with definitions of these groups on the basis of total soil phosphorus. These changes are considered to be important for management and conservation of bushland areas around Sydney.
The seasonal abundance and foraging behaviour of honeyeaters and their potential role in the pollination ofBanksia menziesii
Authors: RAMSAY M. W.
Published: August 2010

Seasonal changes in the abundances of five species of honey‐eaters were assessed in relation to the flowering phenology of Banksia menziesii in banksia woodland near Perth, Western Australia. The total number of honeyeaters was significantly correlated to the number of inflorescences ofB. menziesii. New Holland Honeyeaters. Brown Honeyeaters and Western Spinebills were present throughout the year, whereas the larger honeyeaters (Red and Little Wattlebirds) were observed when B. menziesii was flowering.

The foraging behaviours of the Little Wattlebirds, New Holland Honeyeaters, Brown Honeyeaters and Western Spinebills were similar and all were likely to effect pollination of B. menziesii florets. Differences in their foraging position at an inflorescence, number and direction of foraging probes, and the time spent at an inflorescence were minimal. Western Spinebills used inflorescences lower in the tree crown than the other species. Movements to inflorescences on different plants were inversely related to honeyeater size. Smaller honeyeaters were frequently chased from inflorescences by the larger species, increasing the proportion of distant foraging movements made by the smaller species. Also these interrupted visits were of shorter duration than uninterrupted visits. Visitation by smaller species, especially the Brown Honeyeater, may result in more cross pollinations although the effect on the reproductive success of B, menziesii is unknown.
Movement and modelling of buried seed of the invasive perennial Chrysanthemoides monilifera in coastal dunes and biological control
Authors: NOBLE I. R. , WEISS P. W.
Published: August 2010

Movement in the soil of seeds of the invasive shrub Chrysanthemoides monilifera was studied in relation to the success of proposed biological control treatments. Marked seeds were buried at depths from 0 to 6 cm and recovered after periods of 3–24 months. Survival declined with time but was higher for more deeply buried seeds. The average movement of seeds was 0.7 cm per year downwards which enhances their survival but also tends to remove them from the zone of highest likelihood of germination.

A model was constructed to predict the size of the pool of potentially germinable seed under treatments including pre‐dispersal predation and burning. It indicated that satisfactory control with a pre‐dispersal seed predator will be achieved only if there is a < 95% reduction in seed‐fall to the soil surface over the entire year. A control agent that is 100% effective for most of the year will probably be unsatisfactory if its rate of predation drops to > 90% for a part of the year (e.g. during winter when seed‐fall is abundant). The effectiveness of the control could be enhanced by using intense fires to reduce the soil seed‐pool and to kill many of the mature shrubs. However, the feasibility of this combination of treatments will depend on the reaction of the biological control agent to fire.
The contribution of grazing to plant diversity in alpine grassland and heath
Authors: WILSON SCOTT D.
Published: August 2010

Abstract
Grazing on transplants of a grass, a forb and a tree was examined in low‐diversity grassland and more diverse heath in Australia's Snowy Mountains. Transplants were surrounded by 2 mm mesh netting. In one grassland plot, grazers (probably soil invertebrates) attacked 40–90% of tree and forb seedlings but no grass seedlings. In heath, which had about half the grass cover of grassland, grazers consumed grasses but not trees or forbs. The results suggest that grazers can depress diversity in grassland by attacking species other than grass. In heath, they may promote diversity by attacking only grass and releasing other species from competition.
The sugar and nitrogen content of the gums of Acacia species in the Mountain Ash and Alpine Ash forests of central Victoria and its potential implications for exudivorous arboreal marsupials
Authors: LINDENMAYER D. B. , BOYLE S. , BURGMAN M. A. , MCDONALD D. , TOMKINS B.
Published: August 2010

Abstract
Chemical analysis of the total sugar and total nitrogen content of Acacia dealbata, Acacia obliquinervia and Acacia frigescens gum exudate was completed. These trees were located within stands of 53 year old Mountain Ash, Eucalyptus regnans and Alpine Ash, Eucalyptus delegatensis forest in the Central Highlands of Victoria, southeastern Australia. Values for sugar content ranged from 24 to 68% per sample. Gum samples that were collected in E. regnans forests had a significantly lower (P<0.05) sugar content than those from stands dominated by E. delegatensis. Statistical analyses using Scheffe's S‐test indicated that there was a significant difference in the sugar content of gums between A. dealbata and A. frigescens but not between A. dealbata and A. obliquinervia or A. obliquinervia and A. frigescens. Values for the nitrogen content of Acacia gum varied from 0.2 to 0.7% per sample. Statistical analyses revealed that nitrogen content was significantly influenced (P<0.05) by a combination of three interacting factors: (i) Acacia species; (ii) tree diameter; and (iii) forest type. Therefore, the findings of this study indicate that the sugar and nitrogen content of Acacia gum may vary between forest types and tree species. The gum of Acacia species is an important source of food for several species of arboreal marsupials, and differences in sugar and nitrogen content could be a factor potentially influencing the distribution and abundance of these animals.
Patterns of bird species richness and composition on islands off Arnhem Land, Northern Territory, Australia
Authors: Woinarski J. C. Z. , Fisher A. , Brennan K. , Morris I. , Chatto R.
Published: August 2010

The bird faunas of the adjacent Wessel and English Company island chains were sampled at two scales (0.25 ha quadrats and entire islands). Ninety‐six species were recorded from 226 quadrats, with the most frequently recorded species being mistletoebird Dicaeum hirundinaceum, brown honeyeater Lichmera indistincta, silver‐crowned friarbird Philemon argenticeps, bar‐shouldered dove Geopelia humeralis, northern fantail Rhipidura rufiventris and yellow white‐eye Zosterops lutea. At the quadrat scale, vegetation type was a major determinant of the abundance of individual species (and hence species composition), species richness and total bird abundance. Bird species composition and richness at the quadrat scale was also significantly affected by island isolation (particularly the amount of land within 20 km of the island perimeter). Island size had no effect on quadrat‐scale richness or total abundance. However, the abundance of 10 of the 38 most frequently recorded individual species was significantly related to island size, in most cases even when the comparison was restricted to similar habitats. The most striking cases were rufous fantail Rhipidura rufifrons, mangrove golden whistler Pachycephala melanura, brown honeyeater and yellow white‐eye, which were all significantly more abundant on smaller islands. One hundred and seventy‐one species were recorded from the 62 islands sampled. There was a very tight relationship between island size and the number of terrestrial species (73% of deviance explained) and of all species (84% of deviance explained). This relationship was improved (marginally) when isolation was included in the model. Ordination of islands by their terrestrial bird species composition was related to island size and isolation, and suggested an erratic species composition on small islands.
Photosynthesis and water‐use efficiency: A comparison between invasive (exotic) and non‐invasive (native) species
Authors: MCALPINE KATE G. , JESSON LINLEY K. , KUBIEN DAVID S.
Published: August 2010

Abstract  Invasive species have been hypothesized to out‐compete natives though either a Jack‐of‐all‐trades strategy, where they are able to utilize resources effectively in unfavourable environments, a master‐of‐some, where resource utilization is greater than its competitors in favourable environments, or a combination of the two (Jack‐and‐master). We examined the invasive strategy of Berberis darwinii in New Zealand compared with four co‐occurring native species by examining germination, seedling survival, photosynthetic characteristics and water‐use efficiency of adult plants, in sun and shade environments. Berberis darwinii seeds germinated more in shady sites than the other natives, but survival was low. In contrast, while germination of B. darwinii was the same as the native species in sunny sites, seedling survival after 18 months was nearly twice that of the all native species. The maximum photosynthetic rate of B. darwinii was nearly double that of all native species in the sun, but was similar among all species in the shade. Other photosynthetic traits (quantum yield and stomatal conductance) did not generally differ between B. darwinii and the native species, regardless of light environment. Berberis darwinii had more positive values of δ13C than the four native species, suggesting that it gains more carbon per unit water transpired than the competing native species. These results suggest that the invasion success of B. darwinii may be partially explained by combination of a Jack‐of‐all‐trades scenario of widespread germination with a master‐of‐some scenario through its ability to photosynthesize at higher rates in the sun and, hence, gain a rapid height and biomass advantage over native species in favourable environments.
Global warming and amphibian extinctions in eastern Australia
Authors: LAURANCE WILLIAM F.
Published: August 2010

Abstract  Pounds et al. recently argued that the dramatic, fungal pathogen‐linked extinctions of numerous harlequin frogs (Atelopus spp.) in upland rainforests of South America mostly occurred immediately following exceptionally warm years, implicating global warming as a likely trigger for these extinctions. I tested this hypothesis using temperature data for eastern Australia, where at least 14 upland‐rainforest frog species have also experienced extinctions or striking population declines attributed to the same fungal pathogen, and where temperatures have also risen significantly in recent decades. My analyses provide little direct support for the warm‐year hypothesis of Pounds et al., although my statistical power to detect effects of small (0.5°C) temperature increases was limited. However, I found stronger support for a modified version of the warm‐year hypothesis, whereby frog declines were likely to occur following three consecutive years of unusually warm weather. This trend was apparent only at tropical latitudes, where rising minimum temperatures were greatest. Although much remains uncertain, my findings appear consistent with the notion that global warming could predispose some upland amphibian populations to virulent pathogens.
Territory acquisition in a polymorphic lizard: An experimental approach
Authors: HEALEY M. , OLSSON M.
Published: August 2010

Males of the colour polymorphic Australian painted dragon lizard Ctenophorus pictus occur in red or yellow head colouration. In a previous experiment, we showed that red is associated with a higher probability of winning staged contests for resources (females or space) and that manipulation of male colouration by painting males in the opposing morph changed the dynamics of staged interactions by prolonging them 30‐fold. Thus, colour is linked to behavioural differences between males and is involved in information transfer between competing males. This inherent red dominance could result in yellow males being marginalized to poorer quality territories in terms of access to females, food, perch sites or shade. With an experiment in the wild, we test to what extent this prediction is upheld, and how colour manipulation affects morph‐specific success in territory acquisition when male body size, territory quality and emergence time from hibernation are controlled through manipulation or randomization. There was no significant effect of colour category per se, although on average red males remained closer to the release sites (our proxy for territory acquisition ability) than yellow males and artificially altered morphs moved the furthest away. There was a significant interaction effect between colour category and experimental release position, which may be linked to differences in how exposed (or not) these positions were and morph‐specific ability to cope with such exposure (e.g. ‘boldness’). Our data show that territory acquisition success is not merely a function of competitive ability but a composite outcome of a suite of factors, including signal perception.
The habitat requirements of four sympatric rock‐dwelling macropods of the Australian monsoon tropics
Authors: TELFER WENDY R. , GRIFFITHS ANTHONY D. , BOWMAN DAVID M. J. S.
Published: August 2010

A high diversity of rock‐dwelling macropod species inhabit the tropics of the Northern Territory, Australia. Within this region, individual species have varied distributions, with ranges variously being widespread, restricted, or geographically disjunct with variable levels of sympatry between them. The cause of these patterns is unknown and little is known of the ecology of these rock‐dwelling macropods. We hypothesized that differences in the habitat requirements is the key to understanding the biogeography and sympatry of the species. We examined this hypothesis at both regional and local scales. We analysed records of occurence of Petrogale brachyotis, P. concinna, Macropus bernardus and M. robustus and environmental correlates (such as geology type, vegetation type, distance to drainage and distance to ‘rugged’ terrain) throughout the monsoon tropics using geographic information systems and generalized linear modelling. We surveyed 80 sites across the tropics of the Northern Territory and collected presence‐absence data using scats and environmental correlates to examine fine‐scale habitat requirements. From the regional scale analysis, it was clear that distance to rugged terrain strongly influences presence of all four species. Responses to this variable suggest M. bernardus and P. concinna have greater requirements for rugged terrain, whereas M. robustus and P. brachyotis are found across a broader range of habitats. The local scale analysis suggested presence of M. robustus is primarily driven by vegetation type, M. bernardus by the cover of outcrops, boulders and large rocks, and P. brachyotis by the density of caves. Although these species overlap in their use of habitats, there are also differences in their habitat requirements that are likely to play a role in their niche separation and in some cases their biogeography. However, it is apparent that the distributions of the species have also been influenced by historical factors given the absence of these species from some apparently suitable sites.
Terrestrial activity, movements and spatial ecology of an Australian freshwater turtle, Chelodina longicollis, in a temporally dynamic wetland system
Authors: ROE JOHN H. , GEORGES ARTHUR
Published: August 2010

Animal movements, use of space, activity patterns and habitat use are in part determined by proximal factors such as the landscapes they occupy, seasonal or environmental cues and individual attributes such as sex and body size. Using radio‐telemetry and a drift fence, we examined the contribution of these factors to variation in movements, use of space and terrestrial activity in a freshwater turtle, Chelodina longicollis (Testudines: Chelidae), in south‐east Australia. Movements and use of space depended strongly on landscape attributes, while sex and body size were less important. Movements and use of space also varied seasonally and were partly correlated with rainfall. The high overall vagility of turtles, irrespective of sex and adult body size (13.8 ± 2.8 ha (±SE) home range, 2608 ± 305 m total distance moved, 757 ± 76 m range length), probably reflects a common need to be mobile in a landscape characterized by fluctuating resources in temporary wetlands. Use of temporary wetlands also drives C. longicollis into terrestrial habitats for movements between wetlands and extended refuge. Timing of inter‐wetland movements was associated with rainfall, but most notably for immature individuals and for those moving towards temporary wetlands. Movements of adults, evacuation of the drying wetland and periods of extended refuge (i.e. aestivation) were less dependent upon rainfall if at all. We conclude that movements about and use of the landscape by C. longicollis are under the strong influence of several interacting factors such as patch configuration, seasonal and environmental cues, and in part, body size. We argue that such behaviours are also ultimately under selection from the costs and benefits of these behaviours in the context of fluctuating resources.
Innovation and dynamism
Authors: Kornai János
Published: August 2010

Literature on post‐socialist transformation usually deals with the political, economic and social sides of it, although there have also been important changes in the field of technical advance in the last twenty years. One of capitalism's main virtues is the strong incentive it gives to dynamism, enterprise and the innovation process. Every revolutionary new product (for civilian use) has been brought about by the capitalist system. The socialist system was capable at most of developing new military products. The article analyzes how far the radical difference can be explained by the innate tendencies and basic attributes of the two systems. Our daily lives have been transformed by these new products (for instance, the sphere of information and communications by the computer, the mobile phone and the internet). While many people see all these as favourable changes, fewer discern the causal relation between the capitalist system and rapid technical progress. Yet the usual syllabus of microeconomics does not enlighten students on this important virtue of capitalism, neither it is not adequately emphasized in the statements of leading politicians.
The growth and development of the overwintering larvae in the ant Lasius flavus (Hymenoptera: Formicidae)
Authors: Peakin G. J.
Published: August 2010

The growth and development of the larvae of the ant Lasius flavus (F.) have been traced from the autumn to the following summer. The changes in fresh weight, dry weight, protein content and food reserves in the form of fats and carbohydrates are given. The course of development of the larvae is discussed in relation to the production of queens, workers and males.
The effect of behaviour and body weight on the mechanical design of horns
Authors: Kitchener Andrew
Published: August 2010

A review of the behaviour of bovids and cervids when fighting suggests that it is only the dimensions of the base of horns and antlers which are important mechanically in their design. A fourth power function of the diameter of the base of a horn (the second moment of area (I)) increases linearly with body weight so that there is the same maximum stress in the horn during fighting. This is consistent with the efficient use of materials and is found to be the case for different types of fighting. Sheep and goats fight most forcefully and have a higher ratio of I to body weight than antelopes and deer, which tend to use less forceful wrestling.
The food and feeding ecology of Adélie penguins (Pygoscelis adeliae) and Chinstrap penguins (P. antarctica) at Signy Island, South Orkney Islands
Authors: Lishman G. S.
Published: August 2010

Adélie Pygoscelis adeliae and Chinstrap P. antarctica penguins are important consumers of Southern Ocean marine resources. The stomach contents of adult penguins at Signy Island, South Orkney Islands, were analysed quantitatively throughout the chick‐rearing period. They consisted almost exclusively of Antarctic krill Euphausia superba, Adélies eating 35–63% by number and 23–28% by weight of juvenile krill and Chinstraps 72–87% by number and 90–95% by weight of mature krill, as well as small amounts offish and amphipods. Interspecific dietary differences may partly be attributable to Adélies starting breeding one month before Chinstraps but, as they persist when both are simultaneously rearing chicks, the two species may also forage in somewhat different areas.

Krill data from net hauls indicate a substantial overlap in the size of krill taken by scientific, and probably also commercial, operations and by Adélie and Chinstrap penguins.

Chicks were fed c. 300 g of food 0–5‐0‐8 times per day, Chinstrap chicks without a sibling being fed most frequently. Chicks of both species were most often fed in the late afternoon, and from estimates of swimming speed and feeding frequency adults may feed quite extensively at night.
Soil microarthropods from the Chihuahuan Desert of New Mexico
Authors: Kamill Bernardette W. , Steinberger Y. , Whitford W. G.
Published: August 2010

An account is given of the soil‐ and litter‐dwelling microarthropods collected under three species of desert shrub in southern New Mexico. Particular attention is paid to the acarine component which represents 80% of the microarthropod fauna. Comparisons made with samples collected one hour after wetting show that only the Collembola respond rapidly to changes in the moisture content of the soil. The results of the study suggest that the depth and stability of the surface litter determine the degree to which microarthropod activity is affected by the application of water.
The adhesive organ of the blowfly, Calliphora vomitoria: a functional approach (Diptera: Calliphoridae)
Authors: Walker G. , Yulf A. B. , Ratcliffe J.
Published: August 2010

The external morphology of the terminal region of the fifth tarsal segment of the blowfly, Calliphora vomitoria (L.) has been studied using light and scanning electron microscopy (S.E.M.). The pulvilli, with their numerous tenent hairs of spatulate form projecting from the ventral surface, are responsible for adhesion to smooth surfaces. The two large claws are believed to be important in clinging to irregularities in surfaces. Two footplates, possibly sensory organs, lie in close association with the base of the large ventral seta, the empodium. Blowflies release a non‐volatile lipid secretion on to the spatulate ends of the tenent hairs and this secretion is essential to the adhesion process on smooth surfaces. The force of adhesion has been measured for tethered blowflies on glass using both vertical and lateral pulls; lateral pulls gave much greater forces. It is concluded that surface tension of the lipid secretion under tenent hairs is sufficient to enable successful adhesion to smooth surfaces by blowflies.
An efficient method by which to determine age of carnivores, using dentine rings
Authors: Driscoll Karen M. , Jones G. S. , Nichy F.
Published: August 2010

An efficient, inexpensive technique for cross‐sectioning teeth by means of a low‐speed diamond saw is described. Age determination by means of dentine rings is also discussed and documented.
Larval development and metamorphosis in the marine pulmonate Amphibola crenata (Mollusca: Pulmonata)
Authors: Little C. , Stirling Penny , Pilkington Margaret , Pilkington J.
Published: August 2010

The development of the free‐swimming veliger of Amphibola is followed from hatching to settlement, and the larval structures compared with those of post‐metamorphic juveniles and adult snails. Observations of living specimens and light‐microscope sections were combined with scanning electron microscopy to build up a composite picture of veliger structure.

Four stages in the development of veligers are recognized, each being characterized by the appearance of organ systems such as the mantle cavity, larval heart, adult heart and kidney, and larval pallial gland. At or after metamorphosis, the larval systems (heart, kidney and pallial gland) disappear, and the developing adult organs move to the positions characteristic of adult snails.

Organogenesis in Amphibola veligers is compared with that of prosobranch and opisthobranch larvae, and with that of pulmonate larvae with direct development. The closest similarity is seen to be with opisthobranch veligers.
Influences of weather on reproductive function in male Song sparrows, Melospiza melodia
Authors: Wingfield John C.
Published: August 2010

The avian reproductive cycle is integrated and timed by a variety of environmental factors that include day length, availability of food, nest sites, presence of a mate, etc. However, reproduction can be delayed or disrupted by inclement weather and, until recently, the endocrine responses of avian species to storms were entirely unknown. This communication describes changes in endocrine state in free‐living male Song sparrows, Melospiza melodia, during gonadal recrudescence after a severe winter, and in response to storms in early spring and summer. Both the severe winter weather and an early spring snow storm delayed testicular development, and depressed circulating levels of testosterone. The sparrows did not appear to be stressed, however, since body mass and fat deposits were higher than in birds sampled during the previous spring after a less severe winter.

A second storm occurred in late May and early June when Song sparrows were feeding young. Curiously, plasma levels of testosterone were not affected, but the sparrows did appear to be stressed since there was a significant decline in body mass, and a marked increase in circulating levels of corticosterone. These data suggest that the effects of inclement weather on reproductive function can vary in relation to the stage in the reproductive cycle when the storm strikes, and that the endocrine mechanisms underlying acclimatization to severe meteorological conditions are also different.