bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinship, inbreeding and fine‐scale spatial structure influence gut microbiota in a hindgut‐fermenting tortoise
Authors: Yuan Michael L. , Dean Samantha H. , Longo Ana V. , Rothermel Betsie B. , Tuberville Tracey D. , Zamudio Kelly R. 
Published: March 2015

AbstractHerbivorous vertebrates rely on complex communities of mutualistic gut bacteria to facilitate the digestion of celluloses and hemicelluloses. Gut microbes are often convergent based on diet and gut morphology across a phylogenetically diverse group of mammals. However, little is known about microbial communities of herbivorous hindgut‐fermenting reptiles. Here, we investigate how factors at the individual level might constrain the composition of gut microbes in an obligate herbivorous reptile. Using multiplexed 16S rRNA gene sequencing, we characterized the faecal microbial community of a population of gopher tortoises (Gopherus polyphemus) and examined how age, genetic diversity, spatial structure and kinship influence differences among individuals. We recovered phylotypes associated with known cellulolytic function, including candidate phylum Termite Group 3, suggesting their importance for gopher tortoise digestion. Although host genetic structure did not explain variation in microbial composition and community structure, we found that fine‐scale spatial structure, inbreeding, degree of relatedness and possibly ontogeny shaped patterns of diversity in faecal microbiomes of gopher tortoises. Our findings corroborate widespread convergence of faecal‐associated microbes based on gut morphology and diet and demonstrate the role of spatial and demographic structure in driving differentiation of gut microbiota in natural populations.
Genetic divergence between the sympatric queen morphs of the antMyrmica rubra
Authors: Leppänen Jenni , Seppä Perttu , Vepsäläinen Kari , Savolainen Riitta 
Published: March 2015

AbstractPairs of obligate social parasites and their hosts, where some of the parasites have recently diverged from their host through intraspecific social parasitism, provide intriguing systems for studying the modes and processes of speciation. Such speciation, probably in sympatry, has also been propounded in the antMyrmica rubraand its intraspecific social parasite. In this species, parasitism is associated with queen size dimorphism, and the small microgyne has become a social parasite of the large macrogyne. Here, we investigated the genetic divergence of the host and the parasite queen morphs in 11 localities in southern Finland, using nuclear and mitochondrial markers of queens and workers. We formulated and tested four speciation‐related hypotheses that differed in the degree of genetic divergence between the morphs. The queen morphs were genetically distinct from each other with little hybridization. In the nuclear data, when localities were nested within queen morphs in the hierarchicalamova, 39% of the genetic variation was explained by the queen morph (standardizedF'CT = 0.63, uncorrectedFCT = 0.39), whereas 18% was explained by the locality (F'SC = 0.39,FSC = 0.29). This result corroborated thehypothesis of advanced sympatric speciation. In contrast, the mitochondrialDNAcould not settle between the hierarchical levels of locality and queen morph, thus substantiating equally thehypotheses of incipientandadvanced sympatric speciation. Together, our results support the view that the microgynous parasite has genetically diverged from its macrogynous host to the level of a nascent species.
PfSR1 controls alternative splicing and steady‐state RNA levels in Plasmodium falciparum through preferential recognition of specific RNA motifs
Authors: Eshar Shiri , Altenhofen Lindsey , Rabner Alona , Ross Phil , Fastman Yair , Mandel‐Gutfreund Yael , Karni Rotem , Llinás Manuel , Dzikowski Ron 
Published: March 2015

SummaryPlasmodium species have evolved complex biology to adapt to different hosts and changing environments throughout their life cycle. Remarkably, these adaptations are achieved by a relatively small genome. One way by which the parasite expands its proteome is through alternative splicing (AS). We recently identified PfSR1 as a bona fide Ser/Arg‐rich (SR) protein that shuttles between the nucleus and cytoplasm and regulates AS in Plasmodium falciparum. Here we show that PfSR1 is localized adjacent to the Nuclear Pore Complex (NPC) clusters in the nucleus of early stage parasites. To identify the endogenous RNA targets of PfSR1, we adapted an inducible overexpression system for tagged PfSR1 and performed RNA immunoprecipitation followed by microarray analysis (RIP‐chip) to recover and identify the endogenous RNA targets that bind PfSR1. Bioinformatic analysis of these RNAs revealed common sequence motifs potentially recognized by PfSR1. RNA‐EMSAs show that PfSR1 preferentially binds RNA molecules containing these motifs. Interestingly, we find that PfSR1 not only regulates AS but also the steady‐state levels of mRNAs containing these motifs in vivo.
Basal glucosuria is ubiquitous in critically ill patients
Authors: Brunner Richard , Kurz Annabella , Adelsmayr Gabriel , Holzinger Ulrike 
Published: March 2015

AbstractThe ‘renal threshold for glucose’ has never been evaluated in critically ill patients. Therefore, we aimed to investigate the renal glucose threshold in this patient group using high‐sensitivity urine glucose assays. In this retrospective analysis of prospectively collected data, we analysed 100 consecutive critically ill patients from a medical intensive care unit (ICU). Arterial blood glucose and spot urine glucose were simultaneously quantified daily during the first week after ICU admission. Three hundred seventy‐three pairs of blood/urine glucose were plotted in five pre‐defined categories of blood glucose (<80, 80–109, 110–139, 140–179 and ≥180 mg/dL). Urine glucose values of the five categories were compared using the Kruskal–Wallis test to assess the relation with blood glucose. Urine glucose was detected in virtually all of the urine samples. Urine glucose showed a positive nonlinear correlation with blood glucose and was significantly elevated at blood glucose levels of 140–179 and ≥180 mg/dL compared with lower blood glucose ranges. Basal glucosuria is ubiquitous in critically ill patients. A ‘soft’ renal threshold for glucose is present at blood glucose levels in the range of 140–179 mg/dL.
Results after sacral nerve stimulation for chronic constipation
Authors: Graf W. , Sonesson A.‐C. , Lindberg B. , Åkerud P. , Karlbom U. 
Published: March 2015

AbstractBackgroundSacral nerve stimulation is an established treatment for fecal incontinence and initial reports describe successful results also in subjects with chronic constipation.MethodsConsecutive patients with slow transit or outlet obstruction type constipation were offered external stimulation through a test electrode inserted in a sacral foramen during a 3‐week period. The symptomatic evaluation was based on the number of bowel movements and a validated obstructed defecation score (ODS). A permanent implant was performed provided an overall 50% decrease in symptoms was observed.Key ResultsIn total, 44 patients with chronic constipation were treated with a 3‐week test stimulation. Fifteen experienced a 50% reduction of symptoms and received a permanent implant. Four of the 15 with permanent implants were explanted during the course of the study. Five subjects (11% of original group) reported sustained symptom relief at final follow‐up after a mean of 24 months (range 4–81). Mean ODS score did not change during the treatment. Patients with predominantly slow transit constipation or outlet obstruction did not differ concerning success rate.Conclusions & InferencesSacral nerve stimulation has limited efficacy in unselected patients with chronic constipation and cannot be recommended for treatment on routine basis.
Acute sacral nerve stimulation reduces visceral mechanosensitivity in Rat through spinal opioid pathway
Authors: Langlois L. , Meleine M. , Ouelaa W. , Caremel R. , Bridoux V. , Benard M. , Dechelotte P. , Ducrotte P. , Grise P. , Leroi A. M. , Gourcerol G. 
Published: March 2015

AbstractBackgroundSacral nerve stimulation (SNS) is an alternative surgical treatment of refractory urge incontinence and/or fecal incontinence. Despite its clinical efficacy, the mechanisms of action of SNS remain poorly understood. The aim of this experimental study was to evaluate the effect of SNS on visceral mechanosensitivity in rats.MethodsAnesthetized Sprague–Dawley rats were treated with SNS or sham stimulation. SNS was performed by implanting an electrode close to the sacral nerve root S1. Rats were administered either a non‐selective opioid receptor antagonist (naloxone) or a nitric oxide synthase inhibitor (L‐NAME). Colonic mechanosensitivity was evaluated using the variation of arterial blood pressure as a spino‐bulbar reflex in response to graded isobaric colorectal distension (CRD). C‐fos immunoreactive neurons were quantified in spinal and supraspinal sites. μ‐opioid receptor (MOR) internalization was counted in the sacral spinal cord with sham or effective SNS in response to CRD.Key ResultsSNS reduced visceral mechanosensitivity in response to CRD. This effect was reversed by intrathecal and intraveinous naloxone administration. In both models, CRD induced increased c‐fos immunoreactivity in the dorsal horn neurons of the sacral spinal cord and supraspinal areas. This increase was prevented by SNS. MOR internalization was significantly higher in stimulated group.Conclusions & InferencesSNS impacts on visceral mechanosensitivity by decreasing the spino‐bulbar reflex in response to CRD. Spinal opioid receptors are likely involved in this effect.
Defensive secretions of larvae of a carabid beetle
Authors: Holliday Alison E. , Mattingly Travis M. , Holliday Neil J. 
Published: March 2015

AbstractSecretions of an eversible gland on the metathorax of larvae of Chlaenius cordicollis Kirby (Coleoptera: Carabidae) are investigated by headspace analysis using solid phase microextraction followed by gas chromatography‐mass spectrometry (GC‐MS). Larvae from Manitoba, Canada and Pennsylvania, U.S.A., are sampled. Nine presumed defensive compounds are detected when the gland is everted, and this represents the first characterization of defensive secretions of larvae of a carabid beetle. With the exception of a single component (2‐methoxy‐4‐methylphenol), these compounds are distinct from those found in the defensive secretion of adult C. cordicollis. However, seven are more oxidized versions of the alkylphenolic compounds secreted by adult beetles: three hydroquinones (hydroquinone, methylhydroquinone and 2,3‐dimethylhydroquinone) and four quinones (p‐benzoquinone, toluquinone, 2,3‐dimethylquinone and ethyl‐p‐benzoquinone). An additional alkoxyphenol (2‐methoxy‐4‐ethylphenol) is also detected. Two patterns of composition are observed: in one, p‐benzoquinone and hydroquinone are undetectable and the ratio of toluquinone : 2,3‐dimethylquinone is 1 : 4.6 ± 0.6 (mean ± SE); in the other, all nine compounds are detectable and the ratio of toluquinone : 2,3‐dimethylquinone is 1 : 1.0 ± 0.2. These differences in pattern do not appear to be related to geographical source, sex or age of the larvae.
Involvement of endothelins in deoxycorticosterone acetate–salt hypertension through the modulation of noradrenergic transmission in the rat posterior hypothalamus
Authors: Abramoff Tamara , Guil María J. , Morales Vanina P. , Hope Sandra I. , Höcht Christian , Bianciotti Liliana G. , Vatta Marcelo S. 
Published: March 2015

New Findings

What is the central question of this study?
Does ex vivo administration of endothelin‐1 and endothelin‐3 regulate noradrenergic transmission in the posterior hypothalamus of deoxycorticosterone acetate–salt hypertensive rats compared with normotensive rats?

What is the main finding and its importance?
Endothelin‐1 and endothelin‐3 enhanced diverse mechanisms leading to increased noradrenergic transmission in the posterior hypothalamus of deoxycorticosterone acetate–salt hypertensive rats. Unveiling the role of brain endothelins in hypertension would probably favour the development of new therapeutic targets for the treatment of essential hypertension, which still represents a challenging disease with high mortality.

Brain catecholamines participate in diverse biological functions regulated by the hypothalamus. We have previously reported that endothelin‐1 and endothelin‐3 (ET‐1 and ET‐3) modulate catecholaminergic activity in the anterior and posterior hypothalamus of normotensive rats. The aim of the present study was to evaluate the interaction between endothelins and noradrenergic transmission in the posterior hypothalamus of deoxycorticosterone acetate (DOCA)–salt hypertensive rats. We assessed the effects of ET‐1 and ET‐3 on tyrosine hydroxylase activity and expression, neuronal noradrenaline (NA) release, neuronal NA transporter (NAT) activity and expression, monoamine oxidase activity and NA endogenous content and utilization (as a marker of turnover) in the posterior hypothalamus of DOCA–salt hypertensive rats. In addition, levels of ETA and ETB receptors were assayed in normotensive and hypertensive rats. Results showed that tyrosine hydroxylase activity and total and phosphorylated levels, NAT activity and content, NA release, monoamine oxidase activity and NA utilization were increased in DOCA–salt rats. Both ET‐1 and ET‐3 further enhanced all noradrenergic parameters except for total tyrosine hydroxylase level and NA endogenous content and utilization. The expression of ETA receptors was increased in the posterior hypothalamus of DOCA–salt rats, but ETB receptors showed no changes. These results show that ET‐1 and ET‐3 upregulate noradrenergic activity in the posterior hypothalamus of DOCA–salt hypertensive rats. Our findings suggest that the interaction between noradrenergic transmission and the endothelinergic system in the posterior hypothalamus may be involved in the development and/or maintenance of hypertension in this animal model.
Contractile properties and sarcoplasmic reticulum calcium content in type I and type II skeletal muscle fibres in active aged humans
Authors: Lamboley C. R. , Wyckelsma V. L. , Dutka T. L. , McKenna M. J. , Murphy R. M. , Lamb G. D. 
Published: March 2015

Key points
Muscle weakness in old age is due in large part to an overall loss of skeletal muscle tissue, but it remains uncertain how much also stems from alterations in the properties of the individual muscle fibres.
This study examined the contractile properties and amount of stored intracellular calcium in single muscle fibres of Old (70 ± 4 years) and Young (22 ± 3 years) adults.
The maximum level of force production (per unit cross‐sectional area) in fast twitch fibres in Old subjects was lower than in Young subjects, and the fibres were also less sensitive to activation by calcium.
The amount of calcium stored inside muscle fibres and available to trigger contraction was also lower in both fast‐ and slow‐twitch muscle fibres in the Old subjects.
These findings indicate that muscle weakness in old age stems in part from an impaired capacity for force production in the individual muscle fibres.
AbstractThis study examined the contractile properties and sarcoplasmic reticulum (SR) Ca2+ content in mechanically skinned vastus lateralis muscle fibres of Old (70 ± 4 years) and Young (22 ± 3 years) humans to investigate whether changes in muscle fibre properties contribute to muscle weakness in old age. In type II fibres of Old subjects, specific force was reduced by ∼17% and Ca2+ sensitivity was also reduced (pCa50 decreased ∼0.05 pCa units) relative to that in Young. S‐Glutathionylation of fast troponin I (TnIf) markedly increased Ca2+ sensitivity in type II fibres, but the increase was significantly smaller in Old versus Young (+0.136 and +0.164 pCa unit increases, respectively). Endogenous and maximal SR Ca2+ content were significantly smaller in both type I and type II fibres in Old subjects. In fibres of Young, the SR could be nearly fully depleted of Ca2+ by a combined caffeine and low Mg2+ stimulus, whereas in fibres of Old the amount of non‐releasable Ca2+ was significantly increased (by > 12% of endogenous Ca2+ content). Western blotting showed an increased proportion of type I fibres in Old subjects, and increased amounts of calsequestrin‐2 and calsequestrin‐like protein. The findings suggest that muscle weakness in old age is probably attributable in part to (i) an increased proportion of type I fibres, (ii) a reduction in both maximum specific force and Ca2+ sensitivity in type II fibres, and also a decreased ability of S‐glutathionylation of TnIf to counter the fatiguing effects of metabolites on Ca2+ sensitivity, and (iii) a reduction in the amount of releasable SR Ca2+ in both fibre types.
Extensor motoneurone properties are altered immediately before and during fictive locomotion in the adult decerebrate rat
Authors: MacDonell C. W. , Power K. E. , Chopek J. W. , Gardiner K. R. , Gardiner P. F. 
Published: March 2015

Key points
This is the first report, in adult decerebrate rats, to examine intracellular hindlimb motoneurone properties during quiescence, fictive locomotion and a tonic period immediately before fictive locomotion that is characterized by increased peripheral nerve activity.
It is shown for the first time during fictive locomotion that motoneurones become more responsive in the tonic period, suggesting that the motoneurone pool becomes primed before patterned motor output commences.
Spike frequency adaptation exists in quiescence and during fictive locomotion during constant excitation with injected current but not during centrally driven fictive locomotion.
Motoneurones within the extensor motor pool show changes in excitability even when they are not directly involved in locomotion.
The data show increased responsiveness of motoneurones during locomotion via a lowered threshold for spike initiation and decreased rheobase.
AbstractThis study examined motoneurone properties during fictive locomotion in the adult rat for the first time. Fictive locomotion was induced via electrical stimulation of the mesencephalic locomotor region in decerebrate adult rats under neuromuscular blockade to compare basic and rhythmic motoneurone properties in antidromically identified extensor motoneurones during: (1) quiescence, before and after fictive locomotion; (2) the ‘tonic’ period immediately preceding locomotor‐like activity, whereby the amplitude of peripheral flexor (peroneal) and extensor (tibial) nerves are increased but alternation has not yet occurred; and (3) locomotor‐like episodes. Locomotion was identified by alternating flexor–extensor nerve activity, where the motoneurone either produced membrane oscillations consistent with a locomotor drive potential (LDP) or did not display membrane oscillation during alternating nerve activity. Cells producing LDPs were referred to as such, while those that did not were referred to as ‘idle’ motoneurones. LDP and idle motoneurones during locomotion had hyperpolarized spike threshold (Vth; LDP: 3.8 mV; idle: 5.8 mV), decreased rheobase and an increased discharge rate (LDP: 64%; idle: 41%) during triangular ramp current injection even though the frequency–current slope was reduced by 70% and 55%, respectively. Modulation began in the tonic period immediately preceding locomotion, with a hyperpolarized Vth and reduced rheobase. Spike frequency adaptation did not occur in spiking LDPs or firing generated from sinusoidal current injection, but occurred during a sustained current pulse during locomotion. Input conductance showed no change. Results suggest motoneurone modulation occurs across the pool and is not restricted to motoneurones engaged in locomotion.
Dose domain regularization of MLC leaf patterns for highly complex IMRT plans
Authors: Nguyen Dan , O'Connor Daniel , Yu Victoria Y. , Ruan Dan , Cao Minsong , Low Daniel A. , Sheng Ke 
Published: March 2015

Purpose:The advent of automated beam orientation and fluence optimization enables more complex intensity modulated radiation therapy (IMRT) planning using an increasing number of fields to exploit the expanded solution space. This has created a challenge in converting complex fluences to robust multileaf collimator (MLC) segments for delivery. A novel method to regularize the fluence map and simplify MLC segments is introduced to maximize delivery efficiency, accuracy, and plan quality.Methods:In this work, we implemented a novel approach to regularize optimized fluences in the dose domain. The treatment planning problem was formulated in an optimization framework to minimize the segmentation‐induced dose distribution degradation subject to a total variation regularization to encourage piecewise smoothness in fluence maps. The optimization problem was solved using a first‐order primal‐dual algorithm known as the Chambolle‐Pock algorithm. Plans for 2 GBM, 2 head and neck, and 2 lung patients were created using 20 automatically selected and optimized noncoplanar beams. The fluence was first regularized using Chambolle‐Pock and then stratified into equal steps, and the MLC segments were calculated using a previously described level reducing method. Isolated apertures with sizes smaller than preset thresholds of 1–3 bixels, which are square units of an IMRT fluence map from MLC discretization, were removed from the MLC segments. Performance of the dose domain regularized (DDR) fluences was compared to direct stratification and direct MLC segmentation (DMS) of the fluences using level reduction without dose domain fluence regularization.Results:For all six cases, the DDR method increased the average planning target volume dose homogeneity (D95/D5) from 0.814 to 0.878 while maintaining equivalent dose to organs at risk (OARs). Regularized fluences were more robust to MLC sequencing, particularly to the stratification and small aperture removal. The maximum and mean aperture sizes using the DDR were consistently larger than those from DMS for all tested number of segments.Conclusions:The fluence map to MLC segmentation conversion problem was formulated as a secondary optimization problem in the dose domain to minimize the smoothness‐regularized dose discrepancy. The large scale optimization problem was solved using a primal‐dual algorithm that transformed complicated fluences into maps that were more robust to the MLC segmentation and sequencing, affording fewer and larger segments with minimal degradation to dose distribution.