bluuebunny/crossref_metadata_2025_split huggingface dataset:
The phagocytic capacity and immunological potency of human dendritic cells is improved by α2,6‐sialic acid deficiency
Authors: Cabral M. Guadalupe , Silva Zélia , Ligeiro Dário , Seixas Elsa , Crespo Hélio , Carrascal Mylène A. , Silva Mariana , Piteira Ana R. , Paixão Paulo , Lau Joseph T. , Videira Paula A. 
Published: October 2012

SummaryDendritic cells (DCs) play an essential role in immunity against bacteria by phagocytosis and by eliciting adaptive immune responses. Previously, we demonstrated that human monocyte‐derived DCs (MDDCs) express a high content of cell surface α2,6‐sialylated glycans. However, the relative role of these sialylated structures in phagocytosis of bacteria has not been reported. Here, we show that treatment with a sialidase significantly improved the capacity of both immature and mature MDDCs to phagocytose Escherichia coli. Desialylated MDDCs had a significantly more mature phenotype, with higher expression of MHC molecules and interleukin (IL)‐12, tumour necrosis factor‐α, IL‐6 and IL‐10 cytokines, and nuclear factor‐κB activation. T lymphocytes primed by desialylated MDDCs expressed more interferon‐γ when compared with priming by sialylated MDDCs. Improved phagocytosis required E. coli sialic acids, indicating a mechanism of host–pathogen interaction dependent on sialic acid moieties. The DCs harvested from mice deficient in the ST6Gal.1 sialyltransferase showed improved phagocytosis capacity, demonstrating that the observed sialidase effect was a result of the removal of α2,6‐sialic acid. The phagocytosis of different pathogenic E. coli isolates was also enhanced by sialidase, which suggests that modifications on MDDC sialic acids may be considered in the development of MDDC‐based antibacterial therapies. Physiologically, our findings shed new light on mechanisms that modulate the function of both immature and mature MDDCs, in the context of host–bacteria interaction. Hence, with particular relevance to DC‐based therapies, the engineering of α2,6‐sialic acid cell surface is a novel possibility to fine tune DC phagocytosis and immunological potency.
Differential requirements of CD4+T‐cell signals for effector cytotoxic T‐lymphocyte (CTL) priming and functional memory CTL development at higher CD8+T‐cell precursor frequency
Authors: Umeshappa Channakeshava S. , Nanjundappa Roopa H. , Xie Yufeng , Freywald Andrew , Xu Qingyong , Xiang Jim 
Published: October 2012

SummaryIncreased CD8+ T‐cell precursor frequency (PF) precludes the requirement of CD4+ helper T (Th) cells for primary CD8+ cytotoxic T‐lymphocyte (CTL) responses. However, the key questions of whether unhelped CTLs generated at higher PF are functional effectors, and whether unhelped CTLs can differentiate into functional memory cells at higher PF are unclear. In this study, ovalbumin (OVA) ‐pulsed dendritic cells (DCOVA) derived from C57BL/6, CD40 knockout (CD40−/−) or CD40 ligand knockout (CD40L−/−) mice were used to immunize C57BL/6, Iab−/−, CD40−/− or CD40L−/− mice, whose PF was previously increased with transfer of 1 × 106 CD8+ T cells derived from OVA‐specific T‐cell receptor (TCR) transgenic OTI, OTI(CD40−/−) or OTI(CD40L−/−) mice. All the immunized mice were then assessed for effector and memory CTL responses. Following DC immunization, relatively comparable CTL priming occurred without CD4+ T‐cell help and Th‐provided CD40/CD40L signalling. In addition, the unhelped CTLs were functional effectors capable of inducing therapeutic immunity against established OVA‐expressing tumours. In contrast, the functional memory development of CTLs was severely impaired in the absence of CD4+ T‐cell help and CD40/CD40L signalling. Finally, unhelped memory CTLs failed to protect mice against lethal tumour challenge. Taken together, these results demonstrate that CD4+ T‐cell help at higher PF, is not required for effector CTL priming, but is required for functional memory CTL development against cancer. Our data may impact the development of novel preventive and therapeutic approaches in cancer patients with compromised CD4+ T‐cell functions.
Potential cotton aphid, Aphis gossypii, population suppression by arthropod predators in upland cotton
Authors: Shrestha Ram B. , Parajulee Megha N. 
Published: October 2012

AbstractThe cotton aphid, Aphis gossypii Glover, predation rate of convergent lady beetle, Hippodamia convergens Guerin‐Meneville, was determined by assigning a single predator randomly to each of four prey density treatments in the laboratory. Prey densities included 25, 50, 100, and 200 aphids per Petri dish arena. Predation response was recorded at 1, 4, 8, 16, 24, and 48 h after assigning predators to their prey treatments. Rate of consumption increased through time, with all 25 aphids consumed during the first 4 h of the experiment. At the highest density, adult lady beetle consumed on average 49, 99, 131, 163, 183, and 200 aphids within 1, 4, 8, 16, 24 and 48 h, respectively. Predators showed a curvilinear feeding response in relation to total available time, indicating that convergent lady beetles have the potential to suppress larger populations of aphids through continuous feeding by regulating their predation efficiency during feeding. The analysis of age‐specific mortality in absence of prey revealed that lady beetles could survive for an extended period of time (more than 2 weeks) without prey. The ability of a predator to survive without prey delays or prevents the rebound of pest populations that is a significant factor in natural biological control. A two‐year field sampling of 10 cotton arthropod predator species showed that spiders (27%) were the most dominant foliage dwelling predators in the Texas High Plains cotton followed by convergent lady beetles (23.5%), hooded beetles (13.5%), minute pirate bugs (11%), green lacewings (9.5%), bigeyed bugs (7.5%), scymnus beetles (3%), soft‐winged flower beetles (2%), damsel bugs (1.5%), and assassin bugs (1.5%). A field cage study showed that one H. convergens adult per plant released at prey density of one aphid per leaf kept the aphid population below economic threshold for the entire growing season.
Priming of antiherbivore defensive responses in plants
Authors: Kim Jinwon , Felton Gary W. 
Published: October 2012

AbstractDefense priming is defined as increased readiness of defense induction. A growing body of literature indicates that plants (or intact parts of a plant) are primed in anticipation of impending environmental stresses, both biotic and abiotic, and upon the following stimulus, induce defenses more quickly and strongly. For instance, some plants previously exposed to herbivore‐inducible plant volatiles (HIPVs) from neighboring plants under herbivore attack show faster or stronger defense activation and enhanced insect resistance when challenged with secondary insect feeding. Research on priming of antiherbivore defense has been limited to the HIPV‐mediated mechanism until recently, but significant advances were made in the past three years, including non‐HIPV‐mediated defense priming, epigenetic modifications as the molecular mechanism of priming, and others. It is timely to consider the advances in research on defense priming in the plant–insect interactions.
Locomotion behavior of cao vit gibbon (Nomascus nasutus) living in karst forest in Bangliang Nature Reserve, Guangxi, China
Authors: FAN Pengfei , SCOTT Matthew B. , FEI Hanlan , MA Changyong 
Published: October 2012

AbstractThe cao vit gibbon is a critically endangered species. Only approximately 110 individuals remain in degraded karst forest along the China‐Vietnam border. Karst forest is unusual gibbon habitat. Currently, the canopy height of cao vit gibbon habitat is approximately 10 m. Research on the locomotor behavior of gibbons living in this particular forest type might provide important insight into locomotor stability and variability of gibbons. We used 5 min scan samples to record the locomotion mode, support use and canopy strata of gibbons in 3 groups for 2096 h between January 2008 and December 2009. Although cao vit gibbon habitat has a lower canopy in comparison to that of other forests inhabited by gibbons, cao vit gibbons displayed a similar overall locomotor pattern to other gibbon species (Symphalangus syndactylus, Hylobates lar and Hylobates agilis) in which brachiation dominate their locomotor behavior. Cao vit gibbons spent most of their time travelling on inclined branches (2–10 cm) in the middle stratum through the forest canopy. Adult females appear to more often employ safer modes of locomotion (bridging more often and brachiation less), while adult males choose riskier modes (leaping more and climbing less). As gibbons increased in body weight, as they grew from infant to adult, they tended to use larger supports. This research documented that locomotor behavior in Hylobatidae is strongly determined by anatomical characters, but cao vit gibbons also show the ability to use various supports, enabling them to survive in karst forest.
Melanoma epidemiology, prognosis and trends in Latvia
Authors: Azarjana K. , Ozola A. , Ruklisa D. , Cema I. , Rivosh A. , Azaryan A. , Pjanova D. 
Published: October 2012

AbstractBackground Melanoma incidence and mortality rates are increasing worldwide within the white population. Clinical and histological factors have been usually used for the prognosis and assessment of the risk for melanoma.Objectives The aim of the study was to describe the clinical and histopathological features of the cutaneous melanoma (CM) in the Latvian population, to test the association between melanoma features and patient survival, and to assess the time trends for melanoma incidence.Methods We undertook a descriptive, retrospective analysis of archive data of 984 melanoma patients treated at the largest oncological hospital of Latvia, Riga East University Hospital Latvian Oncology Centre (LOC), between 1998 and 2008. Cox proportional hazards model was used to analyse patient survival and autoregressive models were applied to detect trends in melanoma incidence over time for various categories of melanoma.Results The study showed a significant ascending trend in melanoma incidence in Latvia during the time period from 1998 to 2008 (ß = 1.83, 95% CI = 1.15‐2.91, P = 0.011). Nodular melanoma was the most common tumour subtype with a frequency of 39.2%. Ulceration was present in 45.2% of melanomas. The mean Breslow thickness was 6.0 mm (6.8 mm) and no significant decline in median Breslow thickness was observed during the study period (P = 0.609). A better overall prognosis was detected for females in comparison with males (HR = 1.49; 95% CI = 1.22–1.81; P < 0.001).Conclusions There is a steady increase in melanoma incidence in Latvia with the majority of melanomas diagnosed at late stages with poor prognosis for survival.
Unique gene alterations are induced in FACS‐purified Fos‐positive neurons activated during cue‐induced relapse to heroin seeking
Authors: Fanous Sanya , Guez‐Barber Danielle H. , Goldart Evan M. , Schrama Regina , Theberge Florence R. M. , Shaham Yavin , Hope Bruce T. 
Published: October 2012

AbstractCue‐induced heroin seeking after prolonged withdrawal is associated with neuronal activation and altered gene expression in prefrontal cortex (PFC). However, these previous studies assessed gene expression in all neurons regardless of their activity state during heroin seeking. Using Fos as a marker of neural activity, we describe distinct molecular alterations induced in activated versus non‐activated neurons during cue‐induced heroin seeking after prolonged withdrawal. We trained rats to self‐administer heroin for 10 days (6 h/day) and assessed cue‐induced heroin seeking in extinction tests after 14 or 30 days. We used fluorescent‐activated cell sorting (FACS) to purify Fos‐positive and Fos‐negative neurons from PFC 90 min after extinction testing. Flow cytometry showed that Fos‐immunoreactivity was increased in less than 10% of sparsely distributed PFC neurons. mRNA levels of the immediate early genes fosB, arc, egr1, and egr2, as well as npy and map2k6, were increased in Fos‐positive, but not Fos‐negative, neurons. In support of these findings, double‐label immunohistochemistry indicated substantial coexpression of neuropeptide Y (NPY)‐ and Arc‐immunoreactivity in Fos‐positive neurons. Our data indicate that cue‐induced relapse to heroin seeking after prolonged withdrawal induces unique molecular alterations within activated PFC neurons that are distinct from those observed in the surrounding majority of non‐activated neurons.
Protease‐activated receptor‐1 modulates hippocampal memory formation and synaptic plasticity
Authors: Almonte Antoine G. , Qadri Laura H. , Sultan Faraz A. , Watson Jennifer A. , Mount Daniel J. , Rumbaugh Gavin , Sweatt J. David 
Published: October 2012

AbstractProtease‐activated receptor‐1 (PAR1) is an unusual G‐protein coupled receptor (GPCR) that is activated through proteolytic cleavage by extracellular serine proteases. Although previous work has shown that inhibiting PAR1 activation is neuroprotective in models of ischemia, traumatic injury, and neurotoxicity, surprisingly little is known about PAR1's contribution to normal brain function. Here, we used PAR1−/− mice to investigate the contribution of PAR1 function to memory formation and synaptic function. We demonstrate that PAR1−/− mice have deficits in hippocampus‐dependent memory. We also show that while PAR1−/− mice have normal baseline synaptic transmission at Schaffer collateral‐CA1 synapses, they exhibit severe deficits in N‐methyl‐d‐aspartate receptor (NMDAR)‐dependent long‐term potentiation (LTP). Mounting evidence indicates that activation of PAR1 leads to potentiation of NMDAR‐mediated responses in CA1 pyramidal cells. Taken together, this evidence and our data suggest an important role for PAR1 function in NMDAR‐dependent processes subserving memory formation and synaptic plasticity.
Variance in Coronary Venous Anatomy: A Critical Determinant in Optimal Candidate Selection for Cardiac Resynchronization Therapy
Authors: RANDHAWA ARPANDEEP , SAINI ABHIMANYU , AGGARWAL ANJALI , ROHIT MANOJ K. , SAHNI DAISY 
Published: October 2012

BackgroundKnowledge of coronary sinus (CS) anatomy and its variations is one of the important factors determining the final position of left ventricle pacing lead during cardiac resynchronization therapy.MethodsCoronary venous system anatomy, including number, diameter, and opening angles of tributaries, was studied in 50 normal formalin‐fixed adult cadaveric hearts.ResultsThebesian valve (TV) and Vieussens valve were present in 64% and 60% cases, respectively. CS ostium coverage of ≥75% by TV was seen in 25% (8/32) cases. Number of prominent tributaries lying between anterior interventricular vein and middle cardiac vein varied from 1–4. In 28% of hearts, only one prominent tributary was present. Midlateral vein (average diameter 1.75 ± 0.66 mm) with an average distance of 43.5 ± 12.2 mm from coronary ostium was present in 58% (29/50) hearts, of which it formed an acute angle with CS axis in four (13.39%) cases. Posterolateral vein (average diameter 1.62 ± 0.45 mm) with an average distance of 33.4 ± 11.7 mm from coronary ostium was found in 72% (36/50) cases and formed an acute angle with CS in three (8.33%) cases.ConclusionsRestrictive TV covering ≥75% CS ostium (25% cases), presence of single prominent tributary (28% cases), and formation of acute angle of tributary with CS axis (1/4 cases with anterolateral vein, 4/29 cases with midlateral vein, 3/36 cases with posterolateral vein, and 3/28 cases with posterior veins of the left ventricle) can impede successful cannulation of CS.(PACE 2013; 36:94–102)
Palaeoceanography of Lower Cretaceous Alpine platform carbonates
Authors: FÖllmi Karl B. , Godet Alexis 
Published: October 2012

AbstractShallow‐water carbonate platforms evolve in an interplay of local, regional and global dynamics, thereby generating a detailed record of environmental conditions. Platform sediments constitute important archives of past environmental change and, as such, they are increasingly analysed for the information they contain on wider‐scale patterns. The integration of this information with palaeoceanographic data obtained from deeper‐water sediments provides a powerful tool to develop a more diverse and complete image of past environmental change. In this contribution, the remains of the northern Tethyan carbonate platform of Early Cretaceous age cropping out in the western Swiss Jura and the Helvetic Alps are used to illustrate the advantage of a palaeoceanographic approach in their interpretation. The tools applied are biostratigraphy and chemostratigraphy (carbon and strontium isotopes) in order to obtain a precise age model for correlation with (hemi‐)pelagic sediments in adjacent basins, sequence stratigraphy as a means to reconstruct the impact of sea‐level change, phosphorus stratigraphy as a proxy for trophic levels, facies and microfacies analyses as a gateway to gain better insight into the carbonate factory, and the detailed analysis of platform‐drowning unconformities as an indicator of wider‐scale palaeoenvironmental change. It is shown that changes from periods of predominantly photozoan to predominantly heterozoan carbonate production near the Berriasian–Valanginian boundary and middle early Aptian coincided with substantial increases in phosphorus burial rates and major carbon‐isotope excursions. Furthermore, the majority of the platform‐drowning episodes occurred just prior to and during episodes of major palaeoenvironmental change and, last but not least, the platform itself may have influenced the chemistry of adjacent basins and the carbon‐isotope composition of associated carbonates by the export of periplatform ooze.
Association of phosphate with rhyolite glass in marine Neogene tuffs from Patagonia, Argentina
Authors: Rubinstein Nora , Fazio Ana M. , Scasso Roberto A. , Carey Steven 
Published: October 2012

AbstractThe precipitation/replacement of Ca‐phosphate is a complex process that commonly takes place during the early diagenesis in marine sediments. The unusual occurrence of shallow marine, early diagenetic phosphatic deposits associated with glassy tuffs in the Neogene Gaiman Formation, in the Chubut Province, Patagonia, Argentina, constitutes a good case example for the study of replacement and precipitation of Ca‐phosphate on an unstable substrate. Isocon diagrams illustrate that chemical changes during glass diagenesis include gains in loss on ignition and Ca, and losses of K. These changes are the result of glass hydration during sea water–glass interaction, together with adsorption and diffusion of ions into the bulk shard; combined, these represent an incipient process of volcanic glass replacement by Ca‐phosphate. Subsequent early diagenetic P enrichment in the pore solutions led to phosphate precipitation, associated with pitting on the glass shards and pumice. The associated development of a reactive surface promoted the incorporation of P and Ca into their margins. Lastly, precipitation of calcium phosphate filled the vesicles and other open cavities, inhibiting further glass dissolution. The high porosity and reactivity of the volcanic glass provided an appropriate substrate for phosphate precipitation, leading to the development of authigenic apatite concretions in the volcanic‐glass bearing strata of the Gaiman Formation. This research is of significance for those concerned with marine phosphatic deposits and sheds light on the processes of early diagenetic phosphate precipitation by replacement of an atypical, unstable substrate like hydrated volcanic glass.
The pollen tube: a soft shell with a hard core
Authors: Vogler Hannes , Draeger Christian , Weber Alain , Felekis Dimitris , Eichenberger Christof , Routier‐Kierzkowska Anne‐Lise , Boisson‐Dernier Aurélien , Ringli Christoph , Nelson Bradley J. , Smith Richard S. , Grossniklaus Ueli 
Published: October 2012

SummaryPlant cell expansion is controlled by a fine‐tuned balance between intracellular turgor pressure, cell wall loosening and cell wall biosynthesis. To understand these processes, it is important to gain in‐depth knowledge of cell wall mechanics. Pollen tubes are tip‐growing cells that provide an ideal system to study mechanical properties at the single cell level. With the available approaches it was not easy to measure important mechanical parameters of pollen tubes, such as the elasticity of the cell wall. We used a cellular force microscope (CFM) to measure the apparent stiffness of lily pollen tubes. In combination with a mechanical model based on the finite element method (FEM), this allowed us to calculate turgor pressure and cell wall elasticity, which we found to be around 0.3 MPa and 20–90 MPa, respectively. Furthermore, and in contrast to previous reports, we showed that the difference in stiffness between the pollen tube tip and the shank can be explained solely by the geometry of the pollen tube. CFM, in combination with an FEM‐based model, provides a powerful method to evaluate important mechanical parameters of single, growing cells. Our findings indicate that the cell wall of growing pollen tubes has mechanical properties similar to rubber. This suggests that a fully turgid pollen tube is a relatively stiff, yet flexible cell that can react very quickly to obstacles or attractants by adjusting the direction of growth on its way through the female transmitting tissue.
Identification of the Enzyme Responsible forN-Acetylation of Norfloxacin by Microbacterium sp. Strain 4N2-2
Authors: Kim Dae-Wi , Feng Jinhui , Chen Huizhong , Kweon Ohgew , Gao Yuan , Yu Li-Rong , Burrowes Vanessa J. , Sutherland John B. 
Published: October 2012

ABSTRACTMicrobacteriumsp. 4N2-2, isolated from a wastewater treatment plant, converts the antibacterial fluoroquinolone norfloxacin toN-acetylnorfloxacin and three other metabolites. BecauseN-acetylation results in loss of antibacterial activity, identification of the enzyme responsible is important for understanding fluoroquinolone resistance. The enzyme was identified as glutamine synthetase (GS);N-acetylnorfloxacin was produced only under conditions associated with GS expression. The GS gene (glnA) was cloned, and the protein (53 kDa) was heterologously expressed and isolated. Optimal conditions and biochemical properties (KmandVmax) of purified GS were characterized; the purified enzyme was inhibited by Mn2+, Mg2+, ATP, and ADP. The contribution of GS to norfloxacin resistance was shown by using a norfloxacin-sensitiveEscherichia colistrain carryingglnAderived fromMicrobacteriumsp. 4N2-2. The GS ofMicrobacteriumsp. 4N2-2 was shown to act as anN-acetyltransferase for norfloxacin, which produced low-level norfloxacin resistance. Structural and docking analysis identified potential binding sites for norfloxacin at the ADP binding site and for acetyl coenzyme A (acetyl-CoA) at a cleft in GS. The results suggest that environmental bacteria whose enzymes modify fluoroquinolones may be able to survive in the presence of low fluoroquinolone concentrations.
n
-Alkane Chain Length Alters Dietzia sp. Strain DQ12-45-1b Biosurfactant Production and Cell Surface Activity
Authors: Wang Xing-Biao , Nie Yong , Tang Yue-Qin , Wu Gang , Wu Xiao-Lei 
Published: October 2012

ABSTRACT

Upon growth on
n
-hexadecane (C
16
),
n
-tetracosane (C
24
), and
n
-hexatriacontane (C
36
),
Dietzia
sp. strain DQ12-45-1b could produce different glycolipids, phospholipids, and lipopeptides. Interestingly, cultivation with C
36
increased cell surface hydrophobic activity, which attenuated the negative effect of the decline of the emulsification activity. These results suggest that the mechanisms of biosurfactant production and cell surface hydrophobicity are dependent upon the chain lengths of the
n
-alkanes used as carbon sources.