bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contribution of AmyA, an extracellular α‐glucan degrading enzyme, to group A streptococcal host–pathogen interaction
Authors: Shelburne III Samuel A. , Keith David B. , Davenport Michael T. , Beres Stephen B. , Carroll Ronan K. , Musser James M. 
Published: September 2009

Summaryα‐Glucans such as starch and glycogen are abundant in the human oropharynx, the main site of group A Streptococcus (GAS) infection. However, the role in pathogenesis of GAS extracellular α‐glucan binding and degrading enzymes is unknown. The serotype M1 GAS genome encodes two extracellular proteins putatively involved in α‐glucan binding and degradation; pulA encodes a cell wall anchored pullulanase and amyA encodes a freely secreted putative cyclomaltodextrin α‐glucanotransferase. Genetic inactivation of amyA, but not pulA, abolished GAS α‐glucan degradation. The ΔamyA strain had a slower rate of translocation across human pharyngeal epithelial cells. Consistent with this finding, the ΔamyA strain was less virulent following mouse mucosal challenge. Recombinant AmyA degraded α‐glucans into β‐cyclomaltodextrins that reduced pharyngeal cell transepithelial resistance, providing a physiologic explanation for the observed transepithelial migration phenotype. Higher amyA transcript levels were present in serotype M1 GAS strains causing invasive infection compared with strains causing pharyngitis. GAS proliferation in a defined α‐glucan‐containing medium was dependent on the presence of human salivary α‐amylase. These data delineate the molecular mechanisms by which α‐glucan degradation contributes to GAS host–pathogen interaction, including how GAS uses human salivary α‐amylase for its own metabolic benefit.
Platelet‐specific alloantigens and antibodies in Tunisian women after three or more pregnancies
Authors: Skouri H. , Gandouz R. , Kraiem I. , Dridi H. , Bibi M. , Khairi H. , Jemmali M. , Bierling P. 
Published: September 2009

summary.Pregnancy may allow alloimmunization against human platelet antigens (HPA), which can lead to neonatal alloimmune thrombocytopenia (NAIT). The specificities of alloantibodies are closely related to the distribution of the HPA systems. A total of 281 Tunisian multiparous women (mean number of pregnancies: 4.5) were phenotyped for the HPA‐1, ‐3 and ‐5 systems, by monoclonal antibody immobilization of platelet antigens (MAIPA). We searched for antibodies against HPA‐1a, HPA‐3a, HPA‐5b and HPA‐5a in HPA‐1b1b, HPA‐3b3b, HPA‐5a5a and HPA‐5b5b individuals, respectively. The gene frequencies were: 0·83 for HPA‐1a, 0·17 for HPA‐1b, 0·78 for HPA‐3a, 0·22 for HPA‐3b, 0·82 for HPA‐5a and 0·18 for HPA‐5b. Anti‐HPA‐5b antibodies were present in eight sera and anti‐HPA‐3a antibodies were present in one serum. The anti‐HPA‐5b system is the most frequently involved in platelet alloimmunization in Tunisian multiparous women. However, prospective trials are required to confirm this result and to determine the exact frequencies and clinical relevance of platelet alloantibodies in pregnant Tunisian women.
Frequency of Val1016Ile mutation in the voltage‐gated sodium channel gene of Aedes aegypti Brazilian populations
Authors: Martins Ademir Jesus , Lima José Bento Pereira , Peixoto Alexandre Afranio , Valle Denise 
Published: September 2009

SummaryOne of the major insect pyrethroid resistance mechanisms affects its target site, the voltage‐gated sodium channel (Nav). In Aedes aegypti, the Val1016Ile substitution of the AaNav gene is associated to resistance in several Latin American countries. Genotyping of susceptible and resistant mosquitoes from seven Brazilian localities detected the 1016Ile mutation in five populations with a higher frequency of this substitution in resistant specimens in all cases. Furthermore, analysis of nine additional field populations revealed that five also presented the 1016Ile mutation. Our data suggest a recent dissemination and involvement of this substitution with pyrethroid resistance in Brazil.
Underdiagnosis of acute rheumatic fever in primary care settings in a developing country
Authors: Parks Tom , Kado Joseph , Colquhoun Samantha , Carapetis Jonathan , Steer Andrew 
Published: September 2009

SummaryObjectives  To determine the incidence rate, characterize the clinical features and assess the diagnostic evaluation of children presenting with features of acute rheumatic fever (ARF) at two clinics in a region of Fiji where rheumatic heart disease is known to be endemic.Methods  We reviewed 5 years (2003–2008) of primary care records from 15 841 patients aged 4–20 years using a pre‐determined case definition for ARF; and we reviewed detailed clinical data from 944 cases with features of possible ARF.Results  The crude incidence of first episodes of definite ARF in this setting among patients aged 4–20 years was 24.9 per 100 000 person‐years. Joint involvement suggestive of a potential first presentation of ARF but not sufficient for a definite retrospective diagnosis was documented in a further 94 records. There were another 514 cases of joint involvement less suggestive of ARF and 316 cases of unexplained fever with no evidence of localized infection. Patients presenting with potential features of ARF seldom had a diagnostic evaluation sufficient to exclude its diagnosis.Conclusions  The incidence of ARF at these clinics is nearly twice that reported in a local hospital‐based study, but it is likely to under‐represent the actual number of cases presenting to primary care. There is a need for better surveillance for ARF and to develop simple and practical approaches to diagnosing ARF in primary care in low‐resource settings.
Analysis of waiting times on Irish renal transplant list
Authors: Phelan P.J. , O’Kelly P. , O’Neill D. , Little D. , Hickey D. , Keogan M. , Walshe J. , Magee C. , Conlon P.J. 
Published: September 2009

Phelan PJ, O’Kelly P, O’Neill D, Little D, Hickey D, Keogan M, Walshe J, Magee C, Conlon PJ. Analysis of waiting times on Irish renal transplant list. Clin Transplant 2010: 24: 381–385. © 2009 John Wiley & Sons A/S.Abstract: Introduction:  A number of recipient variables have been identified which influence waiting list times for a renal allograft. The aim of this study was to evaluate these factors in the Irish population.Methods:  We examined patients accepted onto the transplant list from January 1, 2000 until December 31, 2005. Inclusion criteria were adults listed for kidney only, deceased donor transplants. We included patients previously transplanted. Patients were censored, but still included in the analysis, if they died while on the list, permanently withdrew from the list or if they were not transplanted at the time of the study.Results:  There were a total of 984 patients accepted onto the waiting list during the study period, of which 745 of these were transplanted. Factors significantly associated with longer waiting times included age above 50 yr, blood group O and high peak panel reactive antibodies level. Gender and patient body mass index were not associated with longer waiting times.Conclusion:  We have identified factors associated with a longer waiting time on the Irish cadaveric renal transplant list. This information can help our patients make informed decisions regarding likely waiting times and the merits of living related transplantation.
From kissing to belly stridulation: comparative analysis reveals surprising diversity, rapid evolution, and much homoplasy in the mating behaviour of 27 species of sepsid flies (Diptera: Sepsidae)
Authors: PUNIAMOORTHY N. , ISMAIL M. R. B. , TAN D. S. H. , MEIER R. 
Published: September 2009

AbstractOur understanding of how fast mating behaviour evolves in insects is rather poor due to a lack of comparative studies among insect groups for which phylogenetic relationships are known. Here, we present a detailed study of the mating behaviour of 27 species of Sepsidae (Diptera) for which a well‐resolved and supported phylogeny is available. We demonstrate that mating behaviour is extremely diverse in sepsids with each species having its own mating profile. We define 32 behavioural characters and document them with video clips. Based on sister species comparisons, we provide several examples where mating behaviour evolves faster than all sexually dimorphic morphological traits. Mapping the behaviours onto the molecular tree reveals much homoplasy, comparable to that observed for third positions of mitochondrial protein‐encoding genes. A partitioned Bremer support (PBS) analysis reveals conflict between the molecular and behavioural data, but behavioural characters have higher PBS values per parsimony‐informative character than DNA sequence characters.
Manifold aspects of specificity in a nematode–bacterium mutualism
Authors: Chapuis É. , Emelianoff V. , Paulmier V. , Le Brun N. , Pagès S. , Sicard M. , Ferdy J.‐B. 
Published: September 2009

AbstractCoevolution in mutualistic symbiosis can yield, because the interacting partners share common interests, to coadaptation: hosts perform better when associated with symbionts of their own locality than with others coming from more distant places. However, as the two partners of a symbiosis might also experience conflicts over part of their life cycle, coadaptation might not occur for all life‐history traits. We investigated this issue in symbiotic systems where nematodes (Steinernema) and bacteria (Xenorhabdus) reproduce in insects they have both contributed to kill. Newborn infective juveniles (IJs) that carry bacteria in their intestine then disperse from the insect cadaver in search of a new host to infect. We ran experiments where nematodes coinfect insects with bacteria that differ from their native symbiont. In both Steinernema carpocapsae/Xenorhabdus nematophila and Steinernema feltiae/Xenorhabdus bovienii symbioses, we detected an overall specificity which favours the hypothesis of a fine‐tuned co‐adaptation process. However, we also found that the life‐history traits involved in specificity strongly differ between the two model systems: when associated with strains that differ too much from their native symbionts, S. carpocapsae has low parasitic success, whereas S. feltiae has low survival in dispersal stage.
Pattern, process and geographic modes of speciation
Authors: FITZPATRICK B. M. , FORDYCE J. A. , GAVRILETS S. 
Published: September 2009

AbstractThe tradition of classifying cases of speciation into discrete geographic categories (allopatric, parapatric and sympatric) fuelled decades of fruitful research and debate. Not surprisingly, as the science has become more sophisticated, this simplistic taxonomy has become increasingly obsolete. Geographic patterns are now reasonably well understood. Sister species are rarely sympatric, implying that sympatric speciation, it its most general sense, is rare. However, sympatric speciation, even in its most restricted population genetic sense, is possible. Several case studies have demonstrated that divergence has occurred in nature without geographic barriers to gene flow. Obviously, different sets of criteria for sympatric speciation will lead to different numbers of qualifying cases. But changing the rules of nomenclature to make ‘sympatric speciation’ more or less common does not constitute scientific progress. Advances in the study of speciation have come from studies of the processes that constrain or promote divergence, and how they are affected by geography.
Ascites and spontaneous bacterial peritonitis: An Asian perspective
Authors: Lee Jung Min , Han Kwang‐Hyub , Ahn Sang Hoon 
Published: September 2009

AbstractAscites is the most common complication of liver cirrhosis, and it develops as a consequence of portal hypertension and splanchnic vasodilatation. Depending on severity, management of ascites consists of diverse strategy, including dietary sodium restriction, diuretic therapy, repeated large‐volume paracentesis with albumin infusion, transjugular intrahepatic portosystemic shunt, and liver transplantation. Recently, advances in medical therapy have been made with satavaptan, a V2 receptor antagonist, vasoconstrictors, such as clonidine, midodrine, or terlipressin, and other categories of drugs, including docarpamine and Chinese herbs. These drugs may serve as useful adjuncts to conventional diuretics in the management of ascites. Besides ascites itself, serious complications, such as spontaneous bacterial peritonitis (SBP) and hepatorenal syndrome, frequently ensue in decompensated cirrhosis. SBP develops from the translocation of bacteria from the intestine, and successful management with early diagnosis and treatment with proper prevention in patients of high risk is necessary. In summary, ascites is a starting point for more serious complications in liver cirrhosis. Although liver transplantation is the fundamental treatment, it is not always feasible, and consequently various means of treatment should be used. Further study, particularly in Asia where hepatitis B virus‐related cirrhosis is predominant, is warranted to improve the clinical outcome.
Spatial density‐dependent parasitism and specificity in the robber flyMallophora ruficauda(Diptera: Asilidae)
Authors: CASTELO MARCELA K. , CORLEY JUAN C. 
Published: September 2009

AbstractThe density‐dependence in parasitism by the robber flyMallophora ruficauda(Diptera: Asilidae) on scarab beetle larvae (Coleoptera: Scarabaeidae) populations was studied in the present research.Mallophora ruficaudais a pestiferous species common in the open grasslands of the Pampas region of South America. Adults are predators of insects and larvae are solitary parasitoids of third instar larvae of several species of scarab beetle (Coleoptera: Scarabaeidae). In contrast with most studied host‐parasitoid interactions, host searching byM. ruficaudais carried out by both larvae and adults. Typically, robber fly females lay eggs on tall grasses from where larvae drop to the ground, and attack hosts which are buried in the soil. We carried out our study at two spatial scales close to 14 apiaries located in the provinces of Buenos Aires and Entre Ríos (Argentina). We found that parasitism is density‐independent at the larger spatial scale and inversely density‐dependent at the smaller one. We also found thatM. ruficaudaselectsCyclocephala signaticollisamong several scarab beetle species. Specificity is observed both at large and small spatial scales. We discuss the implications of both host specificity and host searching behaviour on the observed parasitism patterns.
Bottom‐up effects on a plant‐endophage‐parasitoid system: The role of flower‐head size and chemistry
Authors: DIAS ANDRÉ T. C. , TRIGO JOSÉ ROBERTO , LEWINSOHN THOMAS M. 
Published: September 2009

AbstractThe effects of water and nutrient addition on a trophic chain were studied in a plant‐endophage‐parasitoid system comprised of insects associated with flower heads of Chromolaena squalida (Asteraceae). Nine species of endophages associated with C. squalida flower heads were found, belonging to two families of Diptera – Tephritidae (Cecidochares sp1, Cecidochares sp2, Xanthaciura biocellata, X. chrysura, X. sp. and Neomyopites sp.) and Agromyzidae (Melanagromyza sp.), and two families of Coleoptera – Apionidae (Apion sp.) and Anthicidae (Anthicidae sp.). A factorial field experiment with water and nutrient addition showed that resource availability can affect the developmental process of flower heads. Fertilization increased flower‐head diameter and nitrogen and alkaloid concentrations. Although nutrient availability affected the size and chemistry of flower heads, endophage species did not respond consistently to the experimental treatments. This is contrary to other studies where endophages showed preference for larger flower heads. Thus, the plant vigour hypothesis was not corroborated for our study system. Our results also showed that coupled responses of plants to resource availability (i.e. tissue nutritional quality and investment in growth of the structure that serves as shelter for endophages) can represent distinct kinds of indirect interactions with opposing effects on the herbivore‐parasitoid interaction.
Vulnerability of an Australian anuran tadpole assemblage to the toxic eggs of the invasive cane toad (Bufo marinus)
Authors: CROSSLAND MICHAEL R. , SHINE RICHARD 
Published: September 2009

AbstractThe invasion of cane toads (Bufo marinus) across tropical Australia has fatally poisoned many native predators; the most frequent victims may be tadpoles of native frogs, which die when they consume the toxic eggs of the toads. Field studies have documented high and species‐specific mortality of tadpoles following toad spawning. To clarify the determinants of tadpole vulnerability, we conducted 1593 laboratory trials in which single tadpoles were exposed to 10 toad eggs, either with or without an alternative food source (lettuce). At least some tadpoles within all 15 species tested consumed toad eggs. Interspecific variance in survival rates (from 0 to >70%) was driven by feeding responses not by physiological tolerance to toxins: almost all native tadpoles that consumed eggs died rapidly. Tadpole mortality was decreased by the presence of an alternative food source in four species, increased in two species, and not affected in seven species. In three of four taxa where we tested both small (early‐stage) and large (late‐stage) tadpoles, both mean survival rates and the effects of alternative food on survival shifted with tadpole body size. Trials with one species (Limnodynastes convexiusculus) showed no significant inter‐clutch variation in feeding responses or tolerance to toxins. Overall, our data show that cane toad eggs are highly toxic to native anuran tadpoles, but that whether or not a tadpole is killed by encountering toad eggs depends upon a complex interaction between the native anuran's species, its body size, and whether or not alternative food was present. In nature, larval vulnerability also depends upon the seasonal timing and location of spawning events, and habitat selection and foraging patterns of the tadpoles. Our results highlight the complexity of vulnerability determinants, and identify ecological factors (rather than physiology or feeding behaviour) as the primary determinants of cane toad impact on native tadpoles.
Regulation of kinesin light chain 1 level correlates with the development of morphine reward in the mouse brain
Authors: Bilecki Wiktor , Wawrzczak‐Bargiela Agnieszka , Przewłocki Ryszard 
Published: September 2009

AbstractPersistent changes that take place during the development of opioid addiction are thought to be due to reorganization of synaptic connections in relevant brain circuits. This neuronal plasticity requires trafficking of signaling molecules that are controlled by kinesins. In neurons, kinesin light chain 1 (KLC1) acts as the primary regulator of kinesin action. We observed that KLC1 was enriched in sub‐cortical regions of the brain in C57Bl/6J mice. KLC1 expression was especially enriched in the striatum, hippocampus and amygdala, which are known to be involved in opioid addiction. Our study revealed that conditioning of C57Bl/6J mice with morphine elevated KLC1 levels in the amygdala, frontal cortex and hippocampus, but not in the striatum. Further study revealed that alterations in KLC1 protein levels in the studied brain regions correlated with the expression of morphine‐induced conditioned place preference. In the cortex, hippocampus and amygdala, KLC1 co‐localized with calcium/calmodulin‐dependent protein kinase II (CaMKII), suggesting that KLC1 was present in the cell bodies and dendrites of pyramidal neurons. Our findings indicate that KLC1, a molecule involved in dendritic and axonal transport in the brain, is affected during chronic morphine treatment and may be involved in the development of opioid addiction.
Neuroanatomical correlates of impaired decision‐making and facial emotion recognition in early Parkinson’s disease
Authors: Ibarretxe‐Bilbao Naroa , Junque Carme , Tolosa Eduardo , Marti Maria‐Jose , Valldeoriola Francesc , Bargallo Nuria , Zarei Mojtaba 
Published: September 2009

AbstractDecision‐making and recognition of emotions are often impaired in patients with Parkinson’s disease (PD). The orbitofrontal cortex (OFC) and the amygdala are critical structures subserving these functions. This study was designed to test whether there are any structural changes in these areas that might explain the impairment of decision‐making and recognition of facial emotions in early PD. We used the Iowa Gambling Task (IGT) and the Ekman 60 faces test which are sensitive to the integrity of OFC and amygdala dysfunctions in 24 early PD patients and 24 controls. High‐resolution structural magnetic resonance images (MRI) were also obtained. Group analysis using voxel‐based morphometry (VBM) showed significant and corrected (P < 0.05 FEW‐small volume correction) gray matter (GM) loss in the right amygdala and bilaterally in the OFC in PD patients. Volumetric analyses were also performed but did not yield significant differences between groups. Left lateral GM volume in OFC showed a slight correlation with the IGT, and bilateral OFC GM was strongly correlated with Ekman test performance in PD patients. We conclude that: (i) impairment in decision‐making and recognition of facial emotions occurs at the early stages of PD, (ii) these neuropsychological deficits are accompanied by degeneration of OFC and amygdala, and (iii) bilateral OFC reductions are associated with impaired recognition of emotions, and GM volume loss in left lateral OFC is related to decision‐making impairment in PD.
Activation of nicotinic acetylcholine receptors enhances a slow calcium‐dependent potassium conductance and reduces the firing of stratum oriens interneurons
Authors: Griguoli Marilena , Scuri Rossana , Ragozzino Davide , Cherubini Enrico 
Published: September 2009

AbstractA large variety of distinct locally connected GABAergic cells are present in the hippocampus. By releasing GABA into principal cells and interneurons, they exert a powerful control on neuronal excitability and are responsible for network oscillations crucial for information processing in the brain. Here, whole‐cell patch clamp recordings in current and voltage clamp mode were used to study the functional role of nicotinic acetylcholine receptors (nAChRs) on the firing properties of stratum oriens interneurons in hippocampal slices from transgenic mice expressing enhanced green fluorescent protein in a subpopulation of GABAergic cells containing somatostatin (GIN mice). Unexpectedly, activation of nAChRs by nicotine or endogenously released acetylcholine strongly enhanced spike frequency adaptation. This effect was blocked by apamin, suggesting the involvement of small calcium‐dependent potassium channels (SK channels). Nicotine‐induced reduction in firing frequency was dependent on intracellular calcium rise through calcium‐permeable nAChRs and voltage‐dependent calcium channels activated by the depolarizing action of nicotine. Calcium imaging experiments directly showed that nicotine effects on firing rate were correlated with large increases in intracellular calcium. Furthermore, blocking ryanodine receptors with ryanodine or sarcoplasmic–endoplasmic reticulum calcium ATPase with thapsygargin or cyclopiazonic acid fully prevented the effects of nicotine, suggesting that mobilization of calcium from the internal stores contributed to the observed effects. By regulating cell firing, cholinergic signalling through nAChRs would be instrumental for fine‐tuning the output of stratum oriens interneurons and correlated activity at the network level.