bluuebunny/crossref_metadata_2025_split huggingface dataset:
The impact of ecosystem connectivity on coral reef resilience
Authors: Mumby Peter J , Hastings Alan 
Published: February 2008

Summary

Ontogenetic dispersal of animals has been observed among many ecosystems, but its full ecological significance is poorly understood. By modelling the consequences of ontogenetic reef fish dispersal between Caribbean mangroves and adjacent coral reefs, we quantify the broader implications of ecosystem connectivity for ecosystem function and resilience to climate‐driven disturbance.
Mangrove‐driven enrichment of parrotfish grazing on two coral reef habitats was calculated using empirical data. The consequences of increased grazing were then investigated using a spatial simulation of coral reef dynamics in shallow (depth 3–6 m) and mid‐shelf forereefs (depth 7–15 m).
The largest increase in grazing occurred in shallow reefs, but was found to have negligible consequences for coral population dynamics.
In contrast, relatively weak increases in grazing on deeper reefs had profound consequences: reefs near mangroves were able to experience coral recovery under the most intense hurricane regimes of the Caribbean, whereas those lacking ecosystem connectivity had little capacity for recovery.
This surprising result occurs because reefs exhibit multiple stable equilibria and mangrove enrichment of grazing in mid‐shelf reefs coincides with a zone of system instability. A small increase in grazing shifted the reef beyond a bifurcation point, thereby enhancing resilience massively. A relatively large increase in grazing in shallow reefs had minimal ecosystem consequence because the grazing levels concerned were more than double the levels needed to exceed the corresponding bifurcation point for this habitat.
Synthesis and applications. Caribbean mangroves are being deforested at a faster rate than rainforests, yet their protective role against hurricane damage extends not only shoreward to coastal environments but also seaward to increasing the resilience of offshore coral reefs. Specifically, ontogenetic mechanisms of ecosystem connectivity involving parrotfish may increase the probability that coral populations will recover from climate‐induced changes in hurricane disturbance. Efforts to arrest mangrove deforestation and restore mangrove habitats are likely to increase the likelihood of recovery of corals on mid‐depth (7–15 m) reefs after disturbance. In general, the ecosystem‐level consequences of ontogenetic migration do not correspond necessarily to the magnitude of locally observed effects (i.e. the pattern of grazer enrichment exhibited the opposite pattern to that of its consequences for system resilience). Therefore, caution must be exercised when interpreting the functional significance of changes in species abundance for ecosystem process (e.g. grazing pressure and its implications for coral growth and survival). Impacts of shifting abundance or process are perhaps best appreciated using mechanistic ecosystem models.
Ancient vs. recent processes as factors shaping the genetic variation of the European wild boar: are the effects of the last glaciation still detectable?
Authors: SCANDURA M. , IACOLINA L. , CRESTANELLO B. , PECCHIOLI E. , DI BENEDETTO M. F. , RUSSO V. , DAVOLI R. , APOLLONIO M. , BERTORELLE G. 
Published: February 2008

AbstractThe European wild boar is an important game species, subjected to local extinctions and translocations in the past, and currently enormously and worryingly expanding in some areas where management is urgently required. Understanding the relative roles of ancient and recent events in shaping the genetic structure of this species is therefore not only an interesting scientific issue, but it represents also the basis for addressing future management strategies. In addition, several pig breeds descend from the European wild boar, but the geographical location of the domestication area(s) and the possible introgression of pig genomes into wild populations are still open questions. Here, we analysed the genetic variation in different wild boar populations in Europe. Ten polymorphic microsatellites were typed in 252 wild boars and the mtDNA control region was sequenced in a subset of 145 individuals. Some samples from different pig breeds were also analysed. Our results, which were obtained considering also 612 published mtDNA sequences, suggest that (i) most populations are similarly differentiated, but the major discontinuity is found along the Alps; (ii) except for the Italian populations, European wild boars show the signature of a postglacial demographic expansion; (iii) Italian populations seem to preserve a high proportion of preglaciation diversity; (iv) the demographic decline which occurred in some areas in the last few centuries did not produce a noticeable reduction of genetic variation; (v) signs of human‐mediated gene flow among populations are weak, although in some regions the effects of translocations are detectable and a low degree of pig introgression can be identified; (vi) the hypothesis of an independent domestication centre in Italy is not supported by our data, which in turn confirm that Central European wild boar might have represented an important source for domestic breeds. We can therefore conclude that recent human activities had a limited effect on the wild boar genetic structure. It follows that areas with high variation and differentiation represent natural reservoirs of genetic diversity to be protected avoiding translocations. In this context controlling some populations by hunting is not expected to affect significantly genetic variation in this species.
Congruent population structure inferred from dispersal behaviour and intensive genetic surveys of the threatened Florida scrub‐jay (Aphelocoma cœrulescens)
Authors: COULON A. , FITZPATRICK J. W. , BOWMAN R. , STITH B. M. , MAKAREWICH C. A. , STENZLER L. M. , LOVETTE I. J. 
Published: February 2008

AbstractThe delimitation of populations, defined as groups of individuals linked by gene flow, is possible by the analysis of genetic markers and also by spatial models based on dispersal probabilities across a landscape. We combined these two complimentary methods to define the spatial pattern of genetic structure among remaining populations of the threatened Florida scrub‐jay, a species for which dispersal ability is unusually well‐characterized. The range‐wide population was intensively censused in the 1990s, and a metapopulation model defined population boundaries based on predicted dispersal‐mediated demographic connectivity. We subjected genotypes from more than 1000 individual jays screened at 20 microsatellite loci to two Bayesian clustering methods. We describe a consensus method for identifying common features across many replicated clustering runs. Ten genetically differentiated groups exist across the present‐day range of the Florida scrub‐jay. These groups are largely consistent with the dispersal‐defined metapopulations, which assume very limited dispersal ability. Some genetic groups comprise more than one metapopulation, likely because these genetically similar metapopulations were sundered only recently by habitat alteration. The combined reconstructions of population structure based on genetics and dispersal‐mediated demographic connectivity provide a robust depiction of the current genetic and demographic organization of this species, reflecting past and present levels of dispersal among occupied habitat patches. The differentiation of populations into 10 genetic groups adds urgency to management efforts aimed at preserving what remains of genetic variation in this dwindling species, by maintaining viable populations of all genetically differentiated and geographically isolated populations.
Drosophilachemoreceptor gene evolution: selection, specialization and genome size
Authors: GARDINER ANASTASIA , BARKER DANIEL , BUTLIN ROGER K. , JORDAN WILLIAM C. , RITCHIE MICHAEL G. 
Published: February 2008

AbstractChemoperception plays a key role in adaptation and speciation in animals, and the senses of olfaction and gustation are mediated by gene families which show large variation in repertoire size among species. InDrosophila,there are around 60 loci of each type and it is thought that ecological specialization influences repertoire size, with increased pseudogenization of loci. Here, we analyse the size of the gustatory and olfactory repertoires among the genomes of 12 species ofDrosophila. We find that repertoire size varies substantially and the loci are evolving by duplication and pseudogenization, with striking examples of lineage‐specific duplication. Selection analyses imply that the majority of loci are subject to purifying selection, but this is less strong in gustatory loci and in loci prone to duplication. In contrast to some other studies, we find that few loci show statistically significant evidence of positive selection. Overall genome size is strongly correlated with the proportion of duplicated chemoreceptor loci, but genome size, specialization and endemism may be interrelated in their influence on repertoire size.
Electron cryotomography reveals novel structures of a recently cultured termite gut spirochete
Authors: Wolgemuth Charles , Goldstein Stuart F. , Charon Nyles W. 
Published: February 2008

SummaryElectron cryotromography, a relatively new methodology in the field of microbiology, has been exploited by Murphy et al. (in this issue of Molecular Microbiology) in their analysis of the recently isolated termite gut spirochete Treponema primitia. Unique structures (bowls, arcades of hooks, cones at the cell ends, two layers of wall material) were evident from the analysis of its surface and internal constituents. These results, coupled to video microscopy analysis of swimming cells, allowed the authors to propose a model of cell motility. This highly significant paper highlights the importance of electron cryotomography to the field of microbiology. It also illustrates that newly cultured recalcitrant bacteria from complex environments are likely to possess novel structures not previously seen in other species.
Maternal diet and the risk of hypospadias and cryptorchidism in the offspring
Authors: Giordano Felice , Carbone Pietro , Nori Fiammetta , Mantovani Alberto , Taruscio Domenica , Figà‐Talamanca Irene 
Published: February 2008

SummaryMale genital tract birth defects have been associated in previous studies with several prenatal exposures to environmental and dietary risk factors. The purpose of this study was to explore the association between hypospadias and cryptorchidism, and the dietary habits of an agricultural population in Italy. A population‐based case–control study was conducted in the Sicilian Province of Ragusa. Cases (n = 90) and controls (n = 202) included births for the period 1998–2002. Data on dietary habits of the mothers, as well as health‐related social, occupational and environmental exposures prior to and during the index birth, were collected through interviews. Adjusted odds ratios (OR) were calculated by logistic regression after adjustment for confounding variables.Increased ORs were observed for mothers of children with hypospadias who, during pregnancy, frequently consumed fish (OR = 2.33 [95% confidence interval (CI) 1.03, 5.31]) and market‐purchased fruit (OR = 5.10 [95% CI 1.31, 19.82]). For cryptorchidism, increased risk was observed in mothers consuming liver (OR = 5.21 [95% CI 1.26, 21.50]), and smoked products (OR = 2.46 [95% CI 1.15, 5.29]). For the two malformations pooled together, increased risk was associated with maternal consumption of liver (OR = 4.38 [95% CI 1.34, 14.26]) and with frequent consumption of wine (OR = 1.98 [95% CI 1.01, 3.86]). This study suggests that some maternal dietary factors may play a role in the development of congenital defects of the male reproductive tract. In particular, our data indicate that further research may be warranted on the endocrine‐disrupting effects resulting from the bioaccumulation of contaminants (fish, liver), pesticides (marketed fruit, wine) and/or potentially toxic food components (smoked products, wine, liver).
Dual function of Arabidopsis glucan synthase‐like genes GSL8 and GSL10 in male gametophyte development and plant growth
Authors: Töller Armin , Brownfield Lynette , Neu Christina , Twell David , Schulze‐Lefert Paul 
Published: February 2008

SummaryMembers of the glucan synthase‐like (GSL) family are believed to be involved in synthesis of the cell‐wall component callose in specialized locations throughout the plant. We identified two members of the Arabidopsis GSL gene family, GSL8 and GSL10, that are independently required for male gametophyte development and plant growth. Analysis of gsl8 and gsl10 mutant pollen during development revealed specific malfunctions associated with asymmetric microspore division. GSL8 and GSL10 are not essential for normal microspore growth and polarity, but play a role in entry of microspores into mitosis. Impaired function of GSL10 also leads to perturbation of microspore division symmetry, irregular callose deposition and failure of generative‐cell engulfment by the cytoplasm of the vegetative cell. Silencing of GSL8 or GSL10 in transgenic lines expressing gene‐specific dsRNAi constructs resulted in a dwarfed growth habit, thereby revealing additional and independent wild‐type gene functions for normal plant growth.
Chilling response of plants: importance of galactolipase, free fatty acids and free radicals*
Authors: Kaniuga Z. 
Published: February 2008

AbstractThe chilling response of plants is complex and based on the interplay of two important metabolic processes – lipolytic degradation of membrane lipids and a set of oxidative reactions leading to lipid peroxidation and membrane damage evoked in chilling‐sensitive (CS) plants subjected to low temperature and light. The effects of chilling of detached leaves and intact plants differ and are often neglected during experiments. In closely‐related species, the activity of several constitutive enzymes (i.e. superoxide dismutase, ascorbate peroxidase and glutathione reductase) appears to be higher in chilling‐tolerant (CT) than in CS species; while in several native, closely‐related CS species, lipid acyl hydrolase (galactolipase) activity is higher than in CT species. Moreover, in chilling‐insensitive (CI) plants, galactolipase activity is very low and is neither activated by detachment of leaves nor under stress conditions in growing plants. Dark and low‐temperature treatments of detached leaves of CS species and post‐chilling recovery of growing plants in the light activate galactolipase, which is responsible for the release of free fatty acids (FFA), the main substrates of peroxidation by lipoxygenase and free radicals. In several CS species, increased galactolipase activity is an important factor contributing to chilling susceptibility. Thus, it seems likely that enhancement of chilling tolerance may be achieved by genetically suppressing galactolipase in order to reduce both the degradation of chloroplast lipids and the level of released FFA, and thereby avoiding the deleterious action of their peroxidation products on plant tissues.
Pollination ofCypripedium plectrochilum(Orchidaceae) byLasioglossumspp. (Halictidae): the roles of generalist attractantsversusrestrictive floral architecture
Authors: Li P. , Luo Y. , Bernhardt P. , Kou Y. , Perner H. 
Published: February 2008

AbstractThe pollination ofCypripedium plectrochilumFranch. was studied in the Huanglong Nature Reserve, Sichuan, China. Although large bees (Bombus,Apis), small bees (Ceratina, Lasioglossum), ants (Formicasp.), true flies (Diptera) and a butterfly were all found to visit the flowers, only small bees, including threeLasioglossumspp. (L. viridiclaucum, L. sichuanenseandL.sp.; Halictidae) and oneCeratinasp., carried the flower’s pollen and contacted the receptive stigma. Measurements of floral architecture showed that interior floral dimensions best fit the exterior dimensions ofLasioglossumspp., leading to the consistent deposition and stigmatic reception of dorsally‐placed, pollen smears. The floral fragrance was dominated by one ketone, 3‐methyl‐Decen‐2‐one. The conversion rate of flowers into capsules in open (insect) pollinated flowers at the site was more than 38%. We conclude that, while pigmentation patterns and floral fragrance attracted a wide variety of insect foragers, canalization of interior floral dimensions ultimately determined the spectrum of potential pollinators in this generalist, food‐mimic flower. A review of the literature showed that the specialised mode of pollination‐by‐deceit inC. plectrochilum, limiting pollinators to a narrow and closely related guild of ‘dupes’ is typical for other members of this genus.
Reproductive biology and pollination mechanisms ofEpidendrum secundum(Orchidaceae). Floral variation: a consequence of natural hybridization?
Authors: Pansarin E. R. , Amaral M. C. E. 
Published: February 2008

AbstractThe phenology, flower morphology, pollination mechanism and reproductive biology ofEpidendrum secundumwere studied in a semi‐deciduous forest at the Serra do Japi (SJ), and in the Atlantic rain forest of Picinguaba, both natural reserves in the State of São Paulo, southeastern Brazil.E. secundumflowers all year round, with a flowering peak between September and January. This species is either a lithophytic or terrestrial herb in the SJ, whereas, in Picinguaba, it grows mainly in disturbed areas along roadsides.E. secundumis pollinated by several species of diurnal Lepidoptera at both study sites. In Picinguaba, whereE. secundumis sympatric withE. fulgensand both share the same pollinators, pollen transference between these two species was recorded.E. secundumis self‐compatible but pollinator‐dependent. It is inter‐compatible withE. fulgens,producing fertile seeds. In contrast to the population of the SJ, in the Picinguaba region, floral morphology is quite variable among plants and some individuals present flowers with characteristics in‐between both sympatric species, suggesting that natural hybridization occasionally occurs. The anthropogenic perturbation is probably the cause of the occurrence ofE. secundumin the Picinguaba region, enabling its contact withE. fulgens.
Effects of elevated CO2 on intra‐specific competition in Sinapis alba: an examination of the role of growth responses to red:far‐red ratio
Authors: Cowan J. E. , Reekie E. G. 
Published: February 2008

AbstractResponse of plants to elevated CO2 differs markedly between individually‐ and competitively‐grown plants, both in terms of mean size and variation about the mean. Using Sinapis alba, we explored whether these contrasting effects are a consequence of the effect of competition on the red:far red (R:FR) light ratio. Plants were grown at both ambient and elevated (700 μl·l−1) CO2 in competitive stands, and as individuals at either a low (0.7) or high (1.25) R:FR ratio at a constant photosynthetic photon fluence rate. Elevated CO2 increased stand biomass by enhancing the growth of canopy dominants, but not the subordinates. As a consequence, elevated CO2 increased the coefficient of variation in size within the stands. Elevated CO2 did not enhance the growth of individually‐grown plants at the low R:FR ratio, but did at the high R:FR ratio. Both the poor response of subordinate plants to elevated CO2 and the increased size inequalities of individuals within the stand can be explained in terms of the effect of the R:FR ratio on CO2 responsiveness. The effect of the R:FR ratio on CO2 response may be related to its effect on allocation patterns and nutrient uptake.
RNA editing in the anticodon of tRNALeu (CAA) occurs before group I intron splicing in plastids of a moss Takakia lepidozioides S. Hatt. & Inoue
Authors: Miyata Y. , Sugita C. , Maruyama K. , Sugita M. 
Published: February 2008

AbstractRNA editing of cytidine (C) to uridine (U) transitions occurs in plastids and mitochondria of most land plants. In this study, we amplified and sequenced the group I intron‐containing tRNALeu gene, trnL‐CAA, from Takakia lepidozioides, a moss. DNA sequence analysis revealed that the T. lepidozioides tRNALeu gene consisted of a 35‐bp 5′ exon, a 469‐bp group I intron and a 50‐bp 3′ exon. The intron was inserted between the first and second position of the tRNALeu anticodon. In general, plastid tRNALeu genes with a group I intron code for a TAA anticodon in most land plants. This strongly suggests that the first nucleotide of the CAA anticodon could be edited in T. lepidozioides plastids. To investigate this possibility, we analysed cDNAs derived from the trnL‐CAA transcripts. We demonstrated that the first nucleotide C of the anticodon was edited to create a canonical UAA anticodon in T. lepidozioides plastids. cDNA sequencing analyses of the spliced or unspliced tRNALeu transcripts revealed that, while the spliced tRNA was completely edited, editing in the unspliced tRNAs were only partial. This is the first experimental evidence that the anticodon editing of tRNA occurs before RNA splicing in plastids. This suggests that this editing is a prerequisite to splicing of pre‐tRNALeu.
Paraheliotropism in Robinia pseudoacacia L.: an efficient strategy to optimise photosynthetic performance under natural environmental conditions
Authors: Arena C. , Vitale L. , De Santo A. Virzo 
Published: February 2008

AbstractWe assessed the contribution of leaf movements to PSII photoprotection against high light and temperature in Robinia pseudoacacia. Gas exchange and chlorophyll a fluorescence measurements were performed during the day at 10:00, 12:00, 15:00 and 18:00 hours on leaves where paraheliotropic movements were restrained (restrained leaves, RL) and on control unrestrained leaves (UL). RL showed a strong decrease of net photosynthesis (An), stomatal conductance (gsH2O), quantum yield of electron transport (ΦPSII), percentage of photosynthesis inhibited by O2 (IPO) and photochemical quenching (qP) in the course of the day, whereas, a significant increase in Ci/Ca and NPQ was observed. Contrary to RL, UL had higher photosynthetic performance that was maintained at elevated levels throughout the day. In the late afternoon, An, gsH2O, ΦPSII and qP of RL showed a tendency to recovery, as compared to 15:00 hours, even if the values remained lower than those measured at 10:00 hours and in UL. In addition, contrary to UL, no recovery was found in Fv/Fm at the end of the study period in RL. Data presented suggest that in R. pseudoacacia, leaf movements, by reducing light interception, represent an efficient, fast and reversible strategy to overcome environmental stresses such as high light and temperature. Moreover, paraheliotropism was able to protect photosystems, avoiding photoinhibitory damage, leading to a carbon gain for the plant.
A possible role of prolyl oligopeptidase during Linum usitatissimum (flax) seed development
Authors: Gutierrez L. , Castelain M. , Verdeil J.‐L. , Conejero G. , Van Wuytswinkel O. 
Published: February 2008

AbstractInvolvement of prolyl oligopeptidases (POPs) in the control of several mammalian peptide hormone signalling pathways has been studied extensively in recent years. POPs are ubiquitous enzymes, but little attention has been paid to understanding their function in plants. Using a cDNA‐AFLP approach, two flax (Linum usitatissimum) POP ESTs were identified as being specifically expressed in the early stages of flax seed development. This specific expression was confirmed using real time RT‐PCR and in situ hybridisation approaches. Seed expression of Arabidopsis POP genes was measured and showed no specificity. Comparison between results obtained with flax and Arabidopsis is discussed in order to address a hypothetic function for POPs during seed formation. These results provide the first insights into POP gene expression and hypothetical function in plants.