bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aggregatibacter actinomycetemcomitans serotype f O‐polysaccharide mediates coaggregation with Fusobacterium nucleatum
Authors: Rupani D. , Izano E. A. , Schreiner H. C. , Fine D. H. , Kaplan J. B. 
Published: February 2008

Background/aims:  Intergeneric bacterial coaggregation may play an important role in plaque development.Methods:  In this study we investigated the coaggregation reaction between two periodontal pathogens, Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum.Results:  Previous studies showed that A. actinomycetemcomitans serotype b strains coaggregate with F. nucleatum strain PK1594, and that A. actinomycetemcomitans serotype b O‐polysaccharide (O‐PS) is the receptor responsible for coaggregation between A. actinomycetemcomitans and F. nucleatum. A. actinomycetemcomitans serotype f O‐PS has been shown to be structurally and antigenically related to serotype b O‐PS. In the present study we show that A. actinomycetemcomitans strain CU1060N, a serotype f strain, also coaggregated with F. nucleatum PK1594. Like coaggregation between serotype b strains and F. nucleatum, coaggregation between CU1060N and F. nucleatum was inhibited by galactose. An O‐PS mutant of CU1060N failed to coaggregate with F. nucleatum.Conclusion:  We concluded that A. actinomycetemcomitans serotype f O‐PS, like serotype b O‐PS, mediates coaggregation between A. actinomycetemcomitans and fusobacteria.
Age‐Related Immunohistochemical and Ultrastructural Changes in Rat Oculomotor Nerve
Authors: Bahcelioglu M. , Elmas C. , Kurkcuoglu A. , Calguner E. , Erdogan D. , Kadıoglu D. , Gözil R. 
Published: February 2008

SummaryDuring ageing process, multiple changes occur on nervous tissue composed of cells and extracellular matrix. Changes on nervous tissues are usually known as degenerative changes on axon structure and connective tissue covering the nerve such as a decrease in the number of fibre or general structural changes. For this purpose, we have studied age‐dependent ultrastructural changes in the rat oculomotor nerve with electron microscopy and also demonstrated collagen structure of the neural sheaths with immunohistochemical techniques. This study was conducted in Gazi University Faculty of Medicine, Department of Anatomy with a total of nine Wistar albino rats. We observed strong collagen type I immunoreactivity in endoneurium and slight to moderate reactivity in fibroblast cytoplasm in 3‐month‐ and 12‐month‐old groups and mild reactivity in 24‐month‐old group. Collagen type IV immunoreactivity was stronger in endoneurium and perineurium in the 3‐month‐ and 12‐month‐old groups compared with collagen type I and fibroblast cytoplasm showed a very strong reactivity. On the other hand, in the 24‐month‐old group, there was slight reactivity in endoneurium and a strong reactivity in perineurium. NGF staining showed moderate to strong reactivity on Schwann cells of the 3‐month‐old group. The immunoreactivity decreased in the 12‐month‐ and 24‐month‐old groups. In the 3‐month‐old rat group, Schwann cell cytoplasm, mitochondrial structure and neurofilaments were normal. In the 12‐month‐old group, there were no changes in organelle distribution, mitochondrial structure and neurofilaments, but there was an increase in the connective tissue. An inconsiderable number of degenerated myelinated nerves were observed. We detected an important decrease in the collagen type I immunoreactivity, which could suggest that the endoneurium, perineurium and epineurium are less resistant to the age‐related collagen loss and that the peripheral nerve is protected by a weaker barrier in the old group. The collagen type IV immunoreactivity was significantly decreased with age. NGF synthesis decreases with age because of Schwann cell structural degeneration or for different reasons. Thus, this could explain the diminished capacity of regeneration and damage of the myelination of the peripheral nerve.
Effects of induced subacute ruminal acidosis on milk fat content and milk fatty acid profile
Authors: Enjalbert F. , Videau Y. , Nicot M. C. , Troegeler‐Meynadier A. 
Published: February 2008

SummaryTwo lactating dairy cows fitted with a rumen cannula received successively diets containing 0%, 20%, 34% and again 0% of wheat on a dry matter basis. After 5, 10 and 11 days, ruminal pH was measured between 8:00 and 16:00 hours, and milk was analysed for fat content and fatty acid profile. Diets with 20% and 34% wheat induced a marginal and a severe subacute ruminal acidosis respectively. After 11 days, diets with wheat strongly reduced the milk yield and milk fat content, increased the proportions of C8:0 to C13:0 even‐ or odd‐chain fatty acids, C18:2 n‐6 and C18:3 n‐3 fatty acids but decreased the proportions of C18:0 and cis‐9 C18:1 fatty acids. Wheat also increased the proportions of trans‐5 to trans‐10 C18:1, the latter exhibiting a 10‐fold increase with 34% of wheat compared with value during the initial 0% wheat period. There was also an increase of trans‐10, cis‐12 C18:2 fatty acid and a decrease of trans‐11 to trans‐16 C18:1 fatty acids. The evolution during adaptation or after return to a 0% wheat diet was rapid for pH but much slower for the fatty acid profile. The mean ruminal pH was closely related to milk fat content, the proportion of odd‐chain fatty acids (linear relationship) and the ratio of trans‐10 C18:1/trans‐11 C18:1 (nonlinear relationship). Such changes in fatty acid profile suggested a possible use for non‐invasive diagnosis of subacute ruminal acidosis.
Prefertilization barriers to interspecific hybridization involving Gossypium hirsutum and four diploid wild species
Authors: Ganesh Ram S. , Hari Ramakrishnan S. , Thiruvengadam V. , Kannan Bapu J. R. 
Published: February 2008

AbstractInterspecific hybridization among species of cotton has lead to improvement in productivity, earliness, fibre quality and resistance to pests and diseases. However, wide crosses is often limited by the operation of either pre‐ or/and post‐fertilization barriers. An investigation on pollen tube behaviour of four wild species in the pistils of Gossypium hirsutum was taken up. Pollen germination was normal in crosses involving Gossypium triphyllum and Gossypium armourianum and markedly inhibited in the crosses involving Gossypium davidsonii and Gossypium thurberi. Pollen tubes reached the pistils and fertilization was accomplished within 8 h after pollination (HAP) in control cross. Even though delay in pollen tube was a common phenomenon in all the four crosses successful fertilization was observed in crosses involving G. triphyllum and G. armourianum, as they reached the ovary at 24 HAP. In crosses with G. davidsonii and G. thurberi, pollen tubes failed to reach the ovary even at 24 HAP indicating the presence of strong stylar and ovarian incompatibility. Measures to overcome such barriers to interspecific hybridization in the incompatible crosses are discussed.
Street children and their relationship with the police
Authors: Ribeiro M.O. 
Published: February 2008

Background:  This paper explores and analyses the experiences of school‐age street children. It specifically addresses the relationship of the street children who live on the streets of São Paulo (a large Brazilian metropolis), in relation to their experiences, with the policemen.Methods:  The paper is a secondary analysis of date previously collected in 1999. The data were collected through individual semi‐structured interviews, with 14 school‐age children frequenting two city public refuges, with their legal guardians' consent. The text from transcribed interviews was organized according to the validity norms of ‘thematic analysis’, a technique of contents analysis method. The decomposing and reconstructing process of that analysis gave rise to thematic categories (among which ‘the police category’) that represented the reconstruction of the difficulties faced by the children in their development.Results and discussion:  The children portrayed the police as an enemy, a fearful figure and one of the most agonizing street experiences. Rarely did the police have a positive image to them. According to the children, police violence occurs in three forms: through systematic police persecution in an effort to remove the children from the streets against their will; actions that had the deliberate intent to humiliate them with verbal or physical aggression; and through alleged sexual abuse, revealed by the children in a veiled manner. The authority that is supposedly intended to protect them is portrayed as one of the most feared social agents.Conclusion:  The reported hostile behaviour of the policemen shows the state of vulnerability of those children living on the street. This situation must be focused like a health problem because it causes injury to development of children. Nurses can help them through organizing assistance to children in situation of personal and social risk in the school nursing and health institution.
How many potential prey species account for the bulk of the diet of mammalian predators? Implications for stable isotope paleodietary analyses
Authors: Pérez‐Claros J. A. , Palmqvist P. 
Published: February 2008

AbstractStable isotopes are useful tools for estimating the relative contribution of different prey to the diet of an extinct predator. Several approaches have been proposed for quantifying these contributions as percentages, but the linear mixing models provide the most reliable estimates. However, these models only yield unique solutions if the number of analyzed isotopes is equal to the number of dietary sources minus one. If stable isotopes from bone collagen (δ13C, δ15N) are used, this implies that a maximum of three prey must account for the bulk of the predator's diet. Here we show that this requirement holds only for the five extant hypercarnivorous canids and probably also for the cheetah (a cursor) and the lynxes among felids, because for these species the dietary contribution of prey sources in terms of biomass is, on average, equal or higher than 55% for the first, 20% for the second and around 10% for the third. However, five to seven prey species account for the bulk of the diet of most stalking felids and also for those omnivorous canids that are not pack hunters. The conclusion is that the linear mixing models will only provide well‐defined solutions using two isotopic ratios in the dietary reconstruction of extinct hypercarnivorous canids, which tend to rely very heavily on only three prey, and probably also in extremely specialized felids with cursorial adaptations or living in temperate habitats.
Strong immune function: a benefit promoting the evolution of sociality?
Authors: Lutermann H. , Bennett N. C. 
Published: February 2008

AbstractLife‐history theory suggests that breeding effort leads to lowered subsequent fecundity and survival. Immunity is a major physiological mechanism regulating survival and trade‐offs between reproductive effort and immune function may be expected. In cooperatively breeding species, breeders may benefit from non‐breeders that perform energetically costly tasks by increased survival. However, this has never been related to immune function. In mammals trade‐offs between reproductive effort and immune function are likely to be mediated through energy that can be stored in adipose tissue. We compared fat mass and immune function measured as spleen mass between breeders and non‐breeders and among the sexes in cooperatively breeding Natal mole‐rats Cryptomys hottentotus natalensis. Assuming that larger spleen size indicates a stronger immune function, we hypothesized that reproductive effort leads to reduced energy stores and thus smaller spleen mass in breeders and expected females to have a larger fat and spleen mass than males. We could establish a relationship between energy stores and spleen mass but found the expected sex‐specific difference only in breeders. Spleen mass was similar between breeders and non‐breeders. The energy cost of reproduction may be compensated for by the contribution of non‐breeders in this cooperative breeder. We suggest that non‐breeders reduce work loads for breeders and thereby allow breeders a higher investment in immune function that may result in improved survival. This could also explain increased survival in mole‐rats and possibly other cooperative vertebrates.
Variation in body size and metamorphic traits of Iberian spadefoot toads over a short geographic distance
Authors: Marangoni F. , Tejedo M. 
Published: February 2008

AbstractDeterminants of geographic variation in body size are often poorly understood, especially in organisms with complex life cycles. We examined patterns of adult body size and metamorphic traits variation in Iberian spadefoot toad (Pelobates cultripes) populations, which exhibit an extreme reduction in adult body size, 71.6% reduction in body mass, within just about 30 km at south‐western Spain. We hypothesized that size at and time to metamorphosis would be predictive of the spatial pattern observed in adult body size. Larvae from eight populations were raised in a common garden experiment at two different larval densities that allow to differentiate whether population divergence was genetically based or was simply a reflection of environmental variation and, in addition, whether this population divergence was modulated by differing crowding larval environments. Larger adult size populations had higher larval growth rates, attaining larger sizes at metamorphosis, and exhibited higher survival than smaller‐sized populations at both densities, although accentuated at a low larval density. These population differences appeared to be consistent once embryo size variation was controlled for, suggesting that this phenotypic divergence is not due to maternal effects. Our results suggest considerable genetic differentiation in metamorphic traits that parallels and may be a causal determinant of geographic variation in adult body size.
An integrative approach to specialization: relationships among feeding morphology, mechanics, behaviour, performance and diet in two syntopic snakes
Authors: Mori A. , Vincent S. E. 
Published: February 2008

AbstractTheoretically, dietary specialists should be morphologically, behaviourally and physiologically specialized to feed efficiently on a subset of the available prey. Yet, relatively few studies have actually tested each of these links in specialist predators, especially in terrestrial vertebrates. We address this issue here by comparing the relationships among feeding morphology, mechanics, swallowing duration and realized diet for a dietary generalist versus a specialist snake when feeding on seasonally abundant frog prey in syntopy. Previous work has shown that the dietary generalist (Elaphe quadrivirgata) consumes both frogs and hard‐bodied prey such as lizards and snakes, whereas the specialist (Rhabdophis tigrinus) feeds primarily on bulky frogs. We thus predicted that the generalist should have a higher bite force to better manipulate hard‐bodied prey, and the specialist should have a larger gape to better handle bulky frogs. Second, we predicted that the increased gape in the specialist should lead to shorter swallowing times and to larger consumed frog sizes in nature. As predicted, the specialist had relatively larger gapes and the generalist had relatively higher potential bite forces, and the specialist swallowed frogs faster than the generalist. Furthermore, field data showed that adult females of the specialist consumed significantly larger frogs than the generalist in syntopy. Overall, this study shows that dietary specialization is tightly linked to phenotypic specialization in a terrestrial vertebrate predator.
Predictors of male residence patterns in groups of black howler monkeys
Authors: Jones C. B. , Milanov V. , Hager R. 
Published: February 2008

AbstractMales may share access to fertilizable females (polygynandry) in one environment while, under other conditions, polygynous (one‐male or ‘harem’) mating is the norm. However, few studies in mammals have empirically investigated the factors predicting when males will coexist in bisexual reproductive units rather than live in one‐male associations with females. We examined patterns of male group membership in a population of black howler monkeys Alouatta pigra residing in two habitats (deciduous and riparian) of a tropical moist forest environment in Belize, Central America. Using general linear and logistic regression modeling, we evaluated nine variables as possible predictors of male residence patterns (one‐male groups or multimale groups). Our results suggest that adult sex ratio and group size are the best predictors of male residence patterns in both habitats. Our findings provide empirical support for theoretical expectations that male reproductive strategies will be a function of habitat‐related demographic patterns and the subsequently varying potential of males to monopolize females in heterogeneous regimes. This study may have important implications for our understanding of features of mammalian societies in which males compete directly for access to females.
Electrophysiological correlates of direct selection by color
Authors: Vierck Esther , Miller Jeff 
Published: February 2008

AbstractWe report an experiment using event‐related potentials (ERPs) to study selection by color uncontaminated from selection by location. Participants monitored an RSVP sequence for a given target letter that could appear in upper‐ or lowercase. Prior to the sequence, a cue indicated the most likely color of the target letter. Replicating E. Vierck and J. Miller (2005), upper‐/lowercase discrimination accuracy was higher following valid than invalid color cues. Within the ERPs, the target onset produced a negative component between 150 and 350 ms at occipital sites, with shorter latencies following valid than invalid cues. We also found larger amplitude components for valid than invalid color cues at central and parietal sites between 150 and 325 ms. The results not only demonstrate clear effects of color cuing on both behavior and ERPs but also suggest that the observed ERP differences between valid versus invalid trials mediate the behavioral effects.
Teenager–peer interaction and its contribution to a family purchase decision: the mediating role of enduring product involvement
Authors: El Aoud Nibrass Hajtaïeb , Neeley Sabrina M. 
Published: February 2008

AbstractThe influencing roles of teenager–peer interaction and enduring product involvement on a teen's contribution to a family purchase decision are examined using survey data from 1008 Tunisian teens. Results demonstrate that enduring product involvement mediates the relationship between teenager–peer interaction and the teenager's contribution. A structural equation model with supporting Bootstrap procedure is presented. Implications, limitations and suggestions for future research are discussed.
Interleukin‐1β up‐regulates TACE to enhance α‐cleavage of APP in neurons: resulting decrease in Aβ production
Authors: Tachida Yuriko , Nakagawa Kazuhiro , Saito Takashi , Saido Takaomi C. , Honda Takashi , Saito Yuko , Murayama Shigeo , Endo Tamao , Sakaguchi Gaku , Kato Akira , Kitazume Shinobu , Hashimoto Yasuhiro 
Published: February 2008

AbstractThe proinflammatory cytokine interleukin (IL)‐1β is up‐regulated in microglial cells surrounding amyloid plaques, leading to the hypothesis that IL‐1β is a risk factor for Alzheimer’s disease. However, we unexpectedly found that IL‐1β significantly enhanced α‐cleavage, indicated by increases in sAPPα and C83, but reduced β‐cleavage, indicated by decreases in sAPPβ and Aβ40/42, in human neuroblastoma SK‐N‐SH cells. IL‐1β did not significantly alter the mRNA levels of BACE1, ADAM‐9, and ADAM‐10, but up‐regulated that of TACE by threefold. The proform and mature form of TACE protein were also significantly up‐regulated. A TACE inhibitor (TAPI‐2) concomitantly reversed the IL‐1β‐dependent increase in sAPPα and decrease in sAPPβ, suggesting that APP consumption in the α‐cleavage pathway reduced its consumption in the β‐cleavage pathway. IL‐1Ra, a physiological antagonist for the IL‐1 receptor, reversed the effects of IL‐1β, suggesting that the IL‐1β‐dependent up‐regulation of α‐cleavage is mediated by the IL‐1 receptor. IL‐1β also induced this concomitant increase in α‐cleavage and decrease in β‐cleavage in mouse primary cultured neurons. Taken together we conclude that IL‐1β is an anti‐amyloidogenic factor, and that enhancement of its signaling or inhibition of IL‐1Ra activity could represent potential therapeutic strategies against Alzheimer’s disease.
Physiological regulation of tau phosphorylation during hibernation
Authors: Su Bo , Wang Xinglong , Drew Kelly L. , Perry George , Smith Mark A. , Zhu Xiongwei 
Published: February 2008

AbstractThe microtubule‐associated protein tau is abnormally hyperphosphorylated in the brains of individuals with Alzheimer disease and other tauopathies, and is believed to play a critical role in the pathogenesis of these diseases. While the mechanisms leading to abnormal tau phosphorylation remain elusive, the recent demonstration of reversible tau phosphorylation during hibernation provides an ideal physiological model to study this critical processin vivo. In this study, arctic ground squirrels (AGS) during hibernation were used to study mechanisms related to tau hyperphosphorylation. Our data demonstrate that tau is hyperphosphorylated at all six sites (S199, T205, S214, S262, S396, and S404) examined in hibernating AGS. Interestingly, only three of these sites (S199, S262, and S404) are dephosphorylated in aroused animals, suggesting a reversible phosphorylation at selective sites. Summer‐active AGS demonstrated the lowest tau phosphorylation at all these sites. To explore the mechanisms underlying increased tau phosphorylation during hibernation, the expression level and enzyme activity of various potential tau kinases and protein phosphatases were examined. The kinetic analysis of enzyme activity at different temperatures revealed differential changes in enzyme activity with temperature decline. Specifically, increased protein kinase A activity, decreased protein phosphatase 2A activity, as well as substantial contribution from glycogen synthase kinase‐3β, likely play a key role in increased tau phosphorylation during hibernation in AGS.
Increased APLP1 expression and neurodegeneration in the frontal cortex of manganese‐exposed non‐human primates
Authors: Guilarte Tomás R. , Burton Neal C. , Verina Tatyana , Prabhu Vinaykumar V. , Becker Kevin G. , Syversen Tore , Schneider Jay S. 
Published: February 2008

AbstractChronic manganese (Mn) exposure produces a neurological syndrome with psychiatric, cognitive, and parkinsonian features. Gene expression profiling in the frontal cortex of Cynomologous macaques receiving 3.3–5.0 mg Mn/kg weekly for 10 months showed that 61 genes were increased and four genes were decreased relative to controls from a total of 6766 genes. Gene changes were associated with cell cycle regulation, DNA repair, apoptosis, ubiquitin‐proteasome system, protein folding, cholesterol homeostasis, axonal/vesicular transport, and inflammation. Amyloid‐β (Aβ) precursor‐like protein 1, a member of the amyloid precursor protein family, was the most highly up‐regulated gene. Immunohistochemistry confirmed increased amyloid precursor‐like protein 1 protein expression and revealed the presence of diffuse Aβ plaques in Mn‐exposed frontal cortex. Cortical neurons and white matter fibers from Mn‐exposed animals accumulated silver grains indicative of on‐going degeneration. Cortical neurons also exhibited nuclear hypertrophy, intracytoplasmic vacuoles, and apoptosis stigmata. p53 immunolabeling was increased in the cytoplasm of neurons and in the nucleus and processes of glial cells in Mn‐exposed tissue. In summary, chronic Mn exposure produces a cellular stress response leading to neurodegenerative changes and diffuse Aβ plaques in the frontal cortex. These changes may explain the subtle cognitive deficits previously demonstrated in these same animals.