bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of novel genes in the oral pathogen Campylobacter rectus
Authors: LaGier M. J. , Threadgill D. S. 
Published: August 2008

Introduction:  A poorly described bacterium, Campylobacter rectus, has been implicated as an etiological agent of periodontal disease. The aim of this study was to use a comparative genomics approach to identify genes that contribute to the lifestyle of C. rectus as an oral pathogen.Methods:  Suppressive subtractive hybridization was used to identify genes encoded by C. rectus ATCC 33238, but not present in the genome of a related Campylobacter species, Campylobacter jejuni ATCC 11168.Results:  Suppressive subtractive hybridization identified 154 unique DNA sequences from the C. rectus genome. Ninety‐two of the 154 clones were classified as C. rectus‐specific, as they did not show significant sequence homology to genes identified in any strain of C. jejuni (blast E‐value >1E‐3). blast analysis predicted that the 92 C. rectus‐specific gene fragments play a role in a variety of biological processes including signal transduction mechanisms (histidine kinase, response regulators, diguanylate cyclases, chemotaxis receptor) and potentially virulence (S‐layer RTX and cysteine desulfhydrase). Further analysis of the C. rectus‐specific clones showed that 10 genes had Campylobacter homologues that were only found in species that commonly reside within the oral cavity of humans and 10 other fragments shared homology only with non‐campylobacter organisms.Conclusions:  These data provide the first substantial insights into the genomic content of C. rectus, a significant oral pathogen. The genes identified in this study are a valuable resource for initiating new research on the virulence of C. rectus during periodontitis.
Proteome analysis of Porphyromonas gingivalis cells placed in a subcutaneous chamber of mice
Authors: Yoshimura M. , Ohara N. , Kondo Y. , Shoji M. , Okano S. , Nakano Y. , Abiko Y. , Nakayama K. 
Published: August 2008

Introduction:  Porphyromonas gingivalis, an oral anaerobic bacterium, is considered a major pathogen for chronic periodontitis. Pathogenic bacteria usually upregulate or downregulate gene expression to combat the protective responses of their hosts.Methods:  To determine what protein is regulated when P. gingivalis cells invade host tissues, we analyzed the proteome of P. gingivalis cells that were placed in a mouse subcutaneous chamber by two‐dimensional gel electrophoresis and mass spectrometry.Results:  Fourteen proteins were upregulated, while four proteins were downregulated. We focused on three upregulated proteins, PG1089 (DNA‐binding response regulator RprY), PG1385 (TPR domain protein), and PG2102 (immunoreactive 61‐kDa antigen), and constructed mutant strains that were defective in these proteins. Mouse abscess model experiments revealed that the mutant strain defective in PG1385 was clearly less virulent than the wild‐type parent strain.Conclusion:  These results indicate that the PG1385 protein is involved in P. gingivalis virulence and that the method used here is useful when investigating the P. gingivalis proteins responsible for virulence.
Biofilm microbial communities of denture stomatitis
Authors: Campos M. S. , Marchini L. , Bernardes L. A. S. , Paulino L. C. , Nobrega F. G. 
Published: August 2008

Introduction:  Denture stomatitis is a common lesion that affects denture wearers. Its multifactorial etiology seems to depend on a complex and poorly characterized biofilm. The purpose of this study was to assess the composition of the microbial biofilm obtained from complete denture wearers with and without denture stomatitis using culture‐independent methods.Methods:  Samples were collected from healthy denture wearers and from patients with denture stomatitis. Libraries comprising about 600 cloned 16S ribosomal DNA (rDNA) bacterial sequences and 192 cloned eukaryotic internal transcribed spacer (ITS) region sequences, obtained by polymerase chain reactions, were analyzed.Results:  The partial 16S rDNA sequences revealed a total of 82 bacterial species identified in healthy subjects and patients with denture stomatitis. Twenty‐seven bacterial species were detected in both biofilms, 29 species were exclusively present in patients with denture stomatitis, and 26 were found only in healthy subjects. Analysis of the ITS region revealed the presence of Candida sp. in both biofilms.Conclusion:  The results revealed the extent of the microbial flora, suggesting the existence of distinct biofilms in healthy subjects and in patients with denture stomatitis.
Maternal Food Regurgitation to Nymphs in Earwigs (Forficula auricularia)
Authors: Staerkle Michael , Kölliker Mathias 
Published: August 2008

AbstractThe occurrence of parental food regurgitation as a form of parental care in (sub‐) social insects has been little studied and is largely based on anectodal and indirect evidence. However, understanding the behavioural mechanisms mediating the benefit of parental care is critical to advance research on the evolution of family interactions. Here, we report results from a study where we experimentally tested the hypothesis that European earwig (Forficula auricularia) females regurgitate food to their nymphs. We used a simple experimental method based on food dyes as colour markers to separate maternal food regurgitation and nymphal self‐feeding as the two components of food intake by nymphs. Two different food dyes were used to label the food offered to the earwig mother and the nymphs respectively. By analysing the colour of the gut content of the nymphs, we demonstrate significant food transfer from the mother to the nymphs. This study demonstrates unambiguously that maternal food regurgitation exists in earwigs and presents a simple and easily applicable technique to trace maternal food regurgitation in the study of insect parental care and family interactions.
MHC and Preferences for Male Odour in the Bank Vole
Authors: Radwan Jacek , Tkacz Aleksandra , Kloch Agnieszka 
Published: August 2008

AbstractHighly polymorphic major histocompatibility complex (MHC) genes are thought to play a central role in the choice of genetically compatible sexual partners in some vertebrates, although the evidence is variable across species. Here, we investigate the association between similarity in the MHC region and sexual preferences in the bank vole Myodes (=Clethrionomys) glareolus (Arvicollinae) in a laboratory setting. Females in post‐partum oestrus were given the choice between the scents of two males in a Y‐maze. Both males were unrelated to the female, but differed in their MHC similarity to the female. We found that females spent more time near the scent of MHC dissimilar males than those, with whom they shared MHC alleles. This suggests that bank voles use MHC‐related cues to choose compatible mates.
Examining the Role of Cuticular Hydrocarbons in Firefly Species Recognition
Authors: South Adam , LeVan Katherine , Leombruni Lisa , Orians Colin M. , Lewis Sara M. 
Published: August 2008

AbstractDuring animal courtship, multiple signals transmitted in different sensory modalities may be used to recognize potential mates. In fireflies (Coleoptera: Lampyridae), nocturnally active species rely on long‐range bioluminescent signals for species, sex, and mate recognition, while several diurnally active species rely on pheromonal signals. Although in many insects non‐volatile cuticular hydrocarbons (CHC) also function in species and sex discrimination, little is known about the potential role of CHC in fireflies. Here, we used gas chromatography to characterize species and sex differences in the CHC profiles of several North American fireflies, including three nocturnal and two diurnal species. Additionally, we conducted behavioral bioassays to determine whether firefly males (the searching sex) were differentially attracted to extracts from conspecific vs. heterospecific females. Gas chromatography revealed that nocturnalPhotinusfireflies had low or undetectable CHC levels in both sexes, while diurnal fireflies showed higher CHC levels. No major sex differences in CHC profiles were observed for any firefly species. Behavioral bioassays demonstrated that males of the diurnal fireflyEllychnia corruscawere preferentially attracted to chemical extracts from conspecific vs. heterospecific females, while males of the remaining species showed no discrimination. These results suggest that while CHC may function as species recognition signals for some diurnal fireflies, these compounds are unlikely to be important contact signals in nocturnalPhotinusfireflies.
Comparison of Color and Body Condition Between Early and Late Breeding King Penguins
Authors: Stephen Dobson F. , Nolan Paul M. , Nicolaus Marion , Bajzak Catherine , Coquel Anne‐Sophie , Jouventin Pierre 
Published: August 2008

AbstractEarly breeding is associated with greater reproductive success in many species. In king penguins, Aptenodytes patagonicus, laying extends for 6 mo. Early breeders may fledge a single chick at best, but late breeders virtually never fledge a chick. For early and late breeders, we compared colored ornaments known to be important in mate choice: yellow–orange feathers of the breast and auricular areas, and an ultraviolet and yellow–orange beak spot. Our purpose was to discern differences between males and females in this highly sexually monomorphic species, as well as to discern whether colored ornaments are more important for the more successful early breeders (aspects of color were hue, chroma, and brightness). For this, we weighed and measured 130 penguins. Early males had greater reflectance of ultraviolet color from the beak spot than did early females and late breeders of both sexes, and the early males were heavier and in better condition than late breeding males or females. Late breeding females were the yellowest in breast hue, a trait that has been linked to immunocompetence. Within pairs, males and females were significantly correlated in body mass, but only early in the breeding season. We concluded that early in the breeding season when reproductive success was greatest, potential mates were not only more similar in body mass, but also that females may have chosen males that had brighter beak spots and were in better body condition.
Body Weight and Rearing Conditions of Males, Female Choice and Paternities in a Small Mammal, Cavia aperea
Authors: Adrian Oliver , Dekomien Gabriele , Epplen Jörg T. , Sachser Norbert 
Published: August 2008

AbstractPatterns of mate choice may be important determinants of a species’ social organisation and mating system. At least two different aspects of female mate choice can be distinguished: choice of a social partner and choice of the genetic father of the offspring. Different characteristics of males can qualify them for these two roles. Although social and reproductive partners have been shown to differ in many species, social association times are often used in laboratory choice tests to infer reproductive preferences. The traits for which females may choose partners are diverse. Body size can correlate with the male’s strength in defending resources or other abilities benefiting the female and her offspring. In species living in social groups, social skills learned from group members during infancy can be important for later reproductive success. In this laboratory study, we conducted choice tests with wild cavies, Cavia aperea, a harem‐living species of South American rodents, to determine social preferences of females towards two simultaneously available males. For offspring sired during these tests, paternities were determined by microsatellite DNA profiling. Males used in the tests differed in body weight and in rearing conditions: Half of the males had been reared in the presence or absence of their father, respectively. Male rearing conditions had no effect on either female social preferences or paternities. Females significantly preferred heavier males as social partners. In five of six tests, the heavier male also sired the offspring. Sires were in most cases but not consistently socially preferred. Heavier males may be preferable as social partners because they are better able to provide females with resources or have more experience in paternal care or predator avoidance as weight correlates with age. When choosing reproductive partners, females may prefer other male traits and the distribution of paternities may also be influenced by sperm competition.
Age‐Related Changes in Nestling Diet of the Cooperatively Breeding Green Woodhoopoe
Authors: Radford Andrew N. 
Published: August 2008

AbstractIn many socially monogamous bird species, parents of altricial young respond to the increasing demands of growing nestlings by increasing their feeding rate and the size of prey items delivered and by altering the types of prey provided. In some cooperatively breeding species, similar changes in feeding rate and prey size have been documented. However, potential changes in the types of prey delivered, both as nestlings age and by different group members, remain largely unexplored. Moreover, studies rarely compare the diet fed to nestlings with that eaten by the provisioning adults themselves. Here, I show that green woodhoopoe (Phoeniculus purpureus) nestlings receive a smaller proportion of spiders and larger proportions of caterpillars and centipedes as they grow older. Both male and female adults delivered a higher proportion of spiders to young nestlings than they ate while self‐feeding, probably in response to particular nutritional requirements of the chicks. However, only males altered the proportions of caterpillars and centipedes delivered, providing smaller proportions to young nestlings than eaten themselves. These prey items may be too large for young nestlings to handle, and males may make a greater adjustment in provisioning diet than females because they collect more caterpillars and centipedes than do females. Although there were sex differences in provisioning diet, there were no differences between same‐sex breeders and helpers in terms of the overall proportions of prey delivered or the changes with nestling age. Hence, individuals of different reproductive status may be following the same provisioning rules, at least in terms of prey type.
Beech decline in Central Europe driven by the interaction between Phytophthora infections and climatic extremes
Authors: Jung T. 
Published: August 2008

SummaryDuring the past decade, and in particular after the wet year 2002 and the dry year 2003, an increasing number of trees and stands of European beech (Fagus sylvatica L.) in Bavaria were showing symptoms typical for Phytophthora diseases: increased transparency and crown dieback, small‐sized and often yellowish foliage, root and collar rot and aerial bleeding cankers up to stem heights of >20 m. Between 2003 and 2007 134 mature beech stands on a broad range of geological substrates were surveyed, and collar rot and aerial bleeding cankers were found in 116 (86.6%) stands. In most stands the majority of beech trees were declining and scattered or clustered mortality occurred. Bark and soil samples were taken from 314 trees in 112 stands, and 11 Phytophthora species were recovered from 253 trees (80.6%) in 104 stands (92.9%). The most frequent species were P. citricola, P. cambivora and P. cactorum. Primary Phytophthora lesions were soon infected by a series of secondary bark pathogens, including Nectria coccinea, and wood decay fungi. In addition, infected trees were often attacked by several bark and wood boring insects leading to rapid mortality. Bark necroses were examined for their probable age in order to determine whether the onset of the current Phytophthora epidemic was correlated to rainfall rates recorded at 22 Bavarian forest ecosystem monitoring stations. A small‐scale survey in nine Bavarian nurseries demonstrated regular infestations of all beech fields with the same range of Phytophthora species. The results indicate that (1) Phytophthora species are regularly associated with beech decline and may also be involved in the complex of ‘Beech Bark Disease’, (2) excessive rainfalls and droughts are triggering the disease, and (3) widespread Phytophthora infestations of nursery stock might endanger current and future silvicultural projects aiming on the replacement of non‐natural conifer stands by beech dominated mixed stands.
Group I mGluRs increase locomotor network excitability in Xenopus tadpoles via presynaptic inhibition of glycinergic neurotransmission
Authors: Chapman Rebecca J. , Issberner Jonathan P. , Sillar Keith T. 
Published: August 2008

AbstractThe group I metabotropic glutamate receptor agonist (S)‐3,5‐dihyroxyphenylglycine (DHPG) increases the frequency of rhythmic swimming activity in Xenopus tadpoles. This study explores the possibility that group I receptor modulation occurs in part via depression of inhibitory synaptic transmission. Applications of the glycine receptor antagonist strychnine occluded the effects of DHPG, providing preliminary evidence that group I receptors affect motor network output by reducing glycinergic transmission. This evidence was supported further by intracellular and whole‐cell patch‐clamp recordings from presumed motorneurons. DHPG applications produced two prominent effects: (i) during swimming activity, glycinergic mid‐cycle IPSPs were reduced in amplitude; and (ii) during quiescent periods, the frequency of spontaneous miniature IPSPs was also reduced. No change in membrane potential or input resistance following group I receptor activation was detected. The reduction in fast synaptic inhibition provides a plausible explanation for the increased excitability of the locomotor network, although other contributory mechanisms activated in parallel by group I receptors cannot be discounted. Aspects of this work have been published previously in abstract form [R. J. Chapman & K. T. Sillar (2003) SFN Abstracts 277.8].
Hypothalamic sites responding to predator threats – the role of the dorsal premammillary nucleus in unconditioned and conditioned antipredatory defensive behavior
Authors: Cezario A. F. , Ribeiro‐Barbosa E. R. , Baldo M. V. C. , Canteras N. S. 
Published: August 2008

AbstractIn this study we provide a comprehensive analysis of the hypothalamic activation pattern during exposure to a live predator or an environment previously associated with a predator. Our results support the view that hypothalamic processing of the actual and the contextual predatory threats share the same circuit, in which the dorsal premammillary nucleus (PMd) plays a pivotal role in amplifying this processing. To further understand the role of the PMd in the circuit organizing antipredatory defensive behaviors, we studied rats with cytotoxic PMd lesions during cat exposure and examined the pattern of behavioral responses as well as how PMd lesions affect the neuronal activation of the systems engaged in predator detection, in contextual memory formation and in defensive behavioral responses. Next, we investigated how pharmacological blockade of the PMd interferes with the conditioned behavioral responses to a context previously associated with a predator, and how this blockade affects the activation pattern of periaqueductal gray (PAG) sites likely to organize the conditioned behavioral responses to the predatory context. Behavioral observations indicate that the PMd interferes with both unconditioned and conditioned antipredatory defensive behavior. Moreover, we have shown that the PMd influences the activation of its major projecting targets, i.e. the ventral part of the anteromedial thalamic nucleus which is likely to influence mnemonic processing, and PAG sites involved in the expression of antipredatory unconditioned and conditioned behavioral responses. Of particular relevance, this work provides evidence to elucidate the basic organization of the neural circuits integrating unconditioned and contextual conditioned responses to predatory threats.
Retinal ganglion cells – spatial organization of the receptive field reduces temporal redundancy
Authors: Tokutake Yoichiro , Freed Michael A. 
Published: August 2008

AbstractAccording to the ‘redundancy reduction’ hypothesis, a visual neuron removes correlations from an image to reduce redundancy in the spike train, thus increasing the efficiency of information coding. However, all elaborations of this general hypothesis have treated spatial and temporal correlations separately. To investigate how a retinal ganglion cell responds to combined spatial and temporal correlations, we selected those cells with center–surround receptive field and presented a stimulus with strong spatiotemporal correlations: we presented a random sequence of intensities (of white noise) to the receptive field center and then activated the surround with the same sequence. We found that, for most cells, activating the surround reduced temporal redundancy in the spike train. Although the surround often reduced the information rate of the spike train it always increased the amount of information per spike. However, when the surround was modulated by a different white‐noise sequence than the center, eliminating spatial–temporal correlations, the surround no longer reduced redundancy or increased information per spike. The proposed mechanism for redundancy reduction is based on the temporal properties of the center and surround: the surround signal is delayed behind the center signal and subtracted from it; this implements a differentiator which removes low frequencies from the stimulus, thus reducing redundancy in the spike train. These results extend the redundancy reduction hypothesis by indicating that the spatial organization of the receptive field into center and surround can reduce temporal redundancy within the spike train of a ganglion cell.
Functional organization of inferior parietal lobule convexity in the macaque monkey: electrophysiological characterization of motor, sensory and mirror responses and their correlation with cytoarchitectonic areas
Authors: Rozzi Stefano , Ferrari Pier Francesco , Bonini Luca , Rizzolatti Giacomo , Fogassi Leonardo 
Published: August 2008

AbstractThe general view on the functional role of the monkey inferior parietal lobule (IPL) convexity mainly derives from studies carried out more than two decades ago and does not account for the functional complexity suggested by more recent neuroanatomical findings. We investigated this issue by recording multi‐ and single units in the IPL convexity of two monkeys and characterizing their somatosensory, visual and motor responses, using a naturalistic (ethologically relevant) approach. These properties were then matched with IPL cytoarchitectonic parcellation. A further aim of this study was to describe the general properties and the localization of IPL mirror neurons, until now not investigated in detail. Results showed that each studied cytoarchitectonic subdivision of the IPL (PF, PFG, PG) is characterized by specific sensory and motor properties. A key feature of the recorded motor neurons is that of coding goal‐directed motor acts. Motor responses are somatotopically organized in a rostro‐caudal fashion, with mouth, hand and arm represented in PF, PFG and PG, respectively, with a certain degree of overlap between adjacent representations. In each subdivision the motor activity is associated with specific somatosensory and visual responses, suggesting that each area organizes motor acts in different space sectors. Mirror neurons have been found mainly in area PFG and their general features appear to be very similar to those of ventral premotor mirror neurons. The present data suggest that the IPL plays an important role in both action organization and action understanding and should be considered part of the motor system.