bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of suspended sediment on fertilization success in the scleractinian coral Pectinia lactuca
Authors: Erftemeijer Paul L.A. , Hagedorn Mary , Laterveer Michael , Craggs Jamie , Guest James R. 
Published: February 2012

The effect of increased levels of suspended sediment on fertilization success in the scleractinian coral Pectinia lactuca was investigated in a laboratory experiment following a mass coral spawning event on reefs off Singapore. Egg–sperm bundles were collected from tank-spawned coral colonies collected from the field several days prior to the anticipated mass spawning. Eggs and sperm from each colony were separated and distributed systematically across replicated treatments (N = 9) with three concentrations of fine suspended sediment. Spawning and embryo development in Pectinia lactuca followed a pattern similar to other scleractinian coral species. There was a significant effect of increased suspended sediment concentration on fertilization success (P < 0.05). Both high- (169 mg l−1) and medium- (43 mg l−1) suspended sediment treatments decreased fertilization success compared to controls. These results imply that increased turbidity levels (whether chronic, such as in the waters around Singapore, or short-term, caused by a dredging operation)—when coinciding with the coral spawning season—may affect the reproductive success of corals and compromise coral recruitment and recovery of degraded reefs.
MicroRNAs: Potentially important regulators for schistosome development and therapeutic targets against schistosomiasis
Authors: CHENG GUOFENG , JIN YOUXIN 
Published: February 2012

SUMMARYMicroRNAs (miRNAs) are small, endogenous non-coding RNA molecules that regulate gene expression post-transcriptionally by targeting the 3′ untranslated region (3′ UTR) of messenger RNAs. Since the discovery of the first miRNA in Caenorhabditis elegans, important regulatory roles for miRNAs in many key biological processes including development, cell proliferation, cell differentiation and apoptosis of many organisms have been described. Hundreds of miRNAs have been identified in various multicellular organisms and many are evolutionarily conserved. Schistosomes are multi-cellular eukaryotes with a complex life-cycle that require genes to be expressed and regulated precisely. Recently, miRNAs have been identified in two major schistosome species, Schistosoma japonicum and S. mansoni. These miRNAs are likely to play critical roles in schistosome development and gene regulation. Here, we review recent studies on schistosome miRNAs and discuss the potential roles of miRNAs in schistosome development and gene regulation. We also summarize the current status for targeting miRNAs and the potential of this approach for therapy against schistosomiasis.
The activity of drug-metabolizing enzymes and the biotransformation of selected anthelmintics in the model tapeworm Hymenolepis diminuta
Authors: BÁRTÍKOVÁ HANA , VOKŘÁL IVAN , SKÁLOVÁ LENKA , KUBÍČEK VLADIMÍR , FIRBASOVÁ JANA , BRIESTENSKÝ DAVID , LAMKA JIŘÍ , SZOTÁKOVÁ BARBORA 
Published: February 2012

SUMMARYThe drug-metabolizing enzymes of some helminths can deactivate anthelmintics and therefore partially protect helminths against these drugs' toxic effect. The aim of our study was to assess the activity of the main drug-metabolizing enzymes and evaluate the metabolism of selected anthelmintics (albendazole, flubendazole, mebendazole) in the rat tapeworm Hymenolepis diminuta, a species often used as a model tapeworm. In vitro and ex vivo experiments were performed. Metabolites of the anthelmintics were detected and identified by HPLC with spectrofluorometric or mass–spectrometric detection. The enzymes of H. diminuta are able to reduce the carbonyl group of flubendazole, mebendazole and several other xenobiotics. Although the activity of a number of oxidation enzymes was determined, no oxidative metabolites of albendazole were detected. Regarding conjugation enzymes, a high activity of glutathione S-transferase was observed. A methyl derivative of reduced flubendazole was the only conjugation metabolite identified in ex vivo incubations of H. diminuta with anthelmintics. The results revealed that H. diminuta metabolized flubendazole and mebendazole, but not albendazole. The biotransformation pathways found in H. diminuta differ from those described in Moniezia expanza and suggest the interspecies differences in drug metabolism not only among classes of helminths, but even among tapeworms.
Assessment of cathepsin D and L-like proteinases of poultry red mite,Dermanyssus gallinae(De Geer), as potential vaccine antigens
Authors: BARTLEY KATHRYN , HUNTLEY JOHN F. , WRIGHT HARRY W. , NATH MINTU , NISBET ALASDAIR J. 
Published: February 2012

SUMMARYVaccination is a feasible strategy for controlling the haematophagous poultry red miteDermanyssus gallinae. A cDNA library enriched for genes upregulated after feeding was created to identify potential vaccine antigens. From this library, a gene (Dg-CatD-1) encoding a 383 amino acid protein (Dg-CatD-1) with homology to cathepsin D lysosomal aspartyl proteinases was identified as a potential vaccine candidate. A second gene (Dg-CatL-1) encoding a 341 amino acid protein (Dg-CatL-1) with homology to cathepsin L cysteine proteinases was also selected for further study. IgY obtained from naturally infested hens failed to detectDg-CatD-1 suggesting that it is a concealed antigen. Conversely,Dg-CatL-1 was detected by IgY derived from natural-infestation, indicating that infested hens are exposed toDg-CatL-1. Mortality rates 120 h after mites had been fed anti-Dg-CatD-1 were significantly higher than those fed control IgY (PF<0·01). In a survival analysis, fitting a proportional hazards model to the time of death of mites, anti-Dg-CatD-1 and anti-Dg-CatL-1 IgY had 4·42 and 2·13 times higher risks of dying compared with controls (PF<0·05).Dg-CatD-1 and L-1 both have potential as vaccine antigens as part of a multi-component vaccine and have the potential to be improved as vaccine antigens using alternative expression systems.
Serine protease inhibitors of parasitic helminths
Authors: MOLEHIN ADEBAYO J. , GOBERT GEOFFREY N. , McMANUS DONALD P. 
Published: February 2012

SUMMARYSerine protease inhibitors (serpins) are a superfamily of structurally conserved proteins that inhibit serine proteases and play key physiological roles in numerous biological systems such as blood coagulation, complement activation and inflammation. A number of serpins have now been identified in parasitic helminths with putative involvement in immune regulation and in parasite survival through interference with the host immune response. This review describes the serpins and smapins (small serine protease inhibitors) that have been identified inAscarisspp.,Brugia malayi, Ancylostoma caninum Onchocerca volvulus, Haemonchus contortus, Trichinella spiralis, Trichostrongylus vitrinus, Anisakis simplex, Trichuris suis, Schistosomaspp.,Clonorchis sinensis, Paragonimus westermaniandEchinococcusspp. and discusses their possible biological functions, including roles in host-parasite interplay and their evolutionary relationships.
Hausdorff dimension for fractals invariant under multiplicative integers
Authors: KENYON RICHARD , PERES YUVAL , SOLOMYAK BORIS 
Published: February 2012

AbstractWe consider subsets of the (symbolic) sequence space that are invariant under the action of the semigroup of multiplicative integers. A representative example is the collection of all 0–1 sequences (xk) such thatxkx2k=0 for allk. We compute the Hausdorff and Minkowski dimensions of these sets and show that they are typically different. The proof proceeds via a variational principle for multiplicative subshifts.
Intrinsic properties and functional circuitry of the AII amacrine cell
Authors: DEMB JONATHAN B. , SINGER JOSHUA H. 
Published: February 2012

AbstractAmacrine cells represent the most diverse class of retinal neuron, comprising dozens of distinct cell types. Each type exhibits a unique morphology and generates specific visual computations through its synapses with a subset of excitatory interneurons (bipolar cells), other amacrine cells, and output neurons (ganglion cells). Here, we review the intrinsic and network properties that underlie the function of the most common amacrine cell in the mammalian retina, the AII amacrine cell. The AII connects rod and cone photoreceptor pathways, forming an essential link in the circuit for rod-mediated (scotopic) vision. As such, the AII has become known as the rod–amacrine cell. We, however, now understand that AII function extends to cone-mediated (photopic) vision, and AII function in scotopic and photopic conditions utilizes the same underlying circuit: AIIs are electrically coupled to each other and to the terminals of some types of ON cone bipolar cells. The direction of signal flow, however, varies with illumination. Under photopic conditions, the AII network constitutes a crossover inhibition pathway that allows ON signals to inhibit OFF ganglion cells and contributes to motion sensitivity in certain ganglion cell types. We discuss how the AII’s combination of intrinsic and network properties accounts for its unique role in visual processing.
The role of starburst amacrine cells in visual signal processing
Authors: TAYLOR W.R. , SMITH R.G. 
Published: February 2012

AbstractStarburst amacrine cells (SBACs) within the adult mammalian retina provide the critical inhibition that underlies the receptive field properties of direction-selective ganglion cells (DSGCs). The SBACs generate direction-selective output of GABA that differentially inhibits the DSGCs. We review the biophysical mechanisms that produce directional GABA release from SBACs and test a network model that predicts the effects of reciprocal inhibition between adjacent SBACs. The results of the model simulations suggest that reciprocal inhibitory connections between closely spaced SBACs should be spatially selective, while connections between more widely spaced cells could be indiscriminate. SBACs were initially identified as cholinergic neurons and were subsequently shown to contain release both acetylcholine and GABA. While the role of the GABAergic transmission is well established, the role of the cholinergic transmission remains unclear.
Involvement of G protein and purines inRhinella arenarumoocyte maturation
Authors: Zelarayán L.I. , Ajmat M.T. , Bonilla F. , Bühler M.I. 
Published: February 2012

SummaryWe investigated the participation of Gαiprotein and of intracellular cAMP levels on spontaneous and progesterone-mediated maturation inRhinella arenarumfully grown follicles and denuded oocytes.Although progesterone is the established maturation inducer in amphibians,Rhinella arenarumoocytes obtained during the reproductive period (competent oocytes) resume meiosis with no need for an exogenous hormonal stimulus if deprived of their enveloping follicular cells, a phenomenon called spontaneous maturation. In amphibian oocytes, numerous signalling mechanisms have been involved in the rapid, non-genomic, membrane effects of progesterone, but most of these are not fully understood.The data presented here demonstrate that activation of the Gαiprotein by Mas-7 induced maturation in non-competent oocytes and also an increase in GVBD (germinal vesicle breakdown) in competent oocytes. Similar results were obtained with intact follicles independent of the season. The activation of adenylyl cyclase (AC) by forskolin seems to inhibit both spontaneous and progesterone-induced GVBD. In addition, the high intracellular levels of cAMP caused by activation of AC by forskolin treatment or addition of db-cAMP inhibited maturation that had been induced by Mas-7 and in a dose-dependent manner. Treatment with H-89, a protein kinase A (PKA) inhibitor, was able to trigger GVBD in a dose-dependent manner in non-competent oocytes and increased the percentages of GVBD in oocytes competent to mature spontaneously. The results obtained with whole follicles and denuded oocytes were similar, which suggested that effects on AC and PKA were not mediated by follicle cells. The fact that Mas-7 was able to induce maturation in non-competent oocytes in a similar manner to progesterone and to increase spontaneous maturation suggests that Gαiactivation could be an important step in meiosis resumption. Thus, the decrease in cAMP as a result of the regulation of the G proteins on AC and the inactivation of PKA by H-89 could contribute to the activation of MPF (maturation promoting factor) and induce maturation of the oocytes ofRhinella arenarum.
Sample dilation and fracture in response to high pore fluid pressure and strain rate in quartz‐rich sandstone and siltstone
Authors: French M. E. , Boutt D. F. , Goodwin L. B. 
Published: February 2012

Natural hydraulic fractures (NHFs) are inferred to form where pore pressure exceeds the least compressive stress by an amount equal to the tensile strength of the rock. We improved upon an experimental protocol that meets the NHF criterion within cylindrical samples with the most tensile effective stress parallel to the sample axis. The effective tensile stresses achieved during these experiments ranged from 17–47 MPa. The pore fluids used had higher viscosities than water and the axial strain rate was rapid (∼10−3s−1) to delay dissipation of fluid pressure by flow. Four experiments on St. Peter Sandstone samples and two on an Abo Formation siltstone sample were performed under these conditions and under drained conditions. None of the drained experiments resulted in failure, but all of the sandstone and one of the siltstone samples fractured in response to elevated pore pressures. Consistent with field and theoretical studies, mechanical heterogeneity was a first order control on fracture location. In the absence of mesoscopic heterogeneity, fracture location coincided with the maximum pore pressure. Samples responded to elevated pore pressures and differential stresses by dilating, the magnitude of which was sufficient to achieve atmospheric pore pressure. Samples failed 2 to 250 s after experiencing the greatest pore pressures, when the effective stresses were no longer tensile. Thus, the high pore pressures and effective tensile stresses experienced early in the experiments were sufficient to fracture the rocks, even though they were not sustained until failure. These results provide insight into processes of fluid‐driven fracture formation.
Estimates of stress and strain rate in mylonites based on the boundary between the fields of grain‐size sensitive and insensitive creep
Authors: Okudaira Takamoto , Shigematsu Norio 
Published: February 2012

Microstructural analyses of mylonites next to the Median Tectonic Line (MTL), SW Japan, reveal a transition in the dominant deformation mechanism of quartz from grain‐size‐insensitive dislocation creep to grain‐size‐sensitive grain‐boundary sliding (GBS). The transition occurred under greenschist‐facies conditions (∼300–400°C) during grain‐size reduction by dynamic recrystallization. The stereologically corrected grain size for the transition is approximately 4.3 μm. At the boundary between the fields of dislocation creep and GBS, as calculated from creep constitutive relations, the differential stress and strain rate for this corrected grain size are estimated to be ∼280 MPa and 1.2 × 10−11 s−1 for 300°C, and ∼110 MPa and 1.0 × 10−10 s−1 for 400°C. The strain rates estimated for the mylonites next to the MTL are much higher than those estimated for the surrounding metamorphic rocks (∼10−14 s−1), and the displacement rates calculated based on the thickness of high‐strain mylonites and their strain rates are comparable with the average slip rates of the most active intraplate faults in Japan. These inferences suggest that the high‐strain mylonite zones next to the MTL are the exhumed downward extension of a seismogenic fault in the ductile region. The zones were highly localized (<10 m) and experienced very high strain rates (10−11 to 10−10 s−1).
Shelf‐basin exchange times of Arctic surface waters estimated from 228Th/228Ra disequilibrium
Authors: Rutgers van der Loeff M. , Cai P. , Stimac I. , Bauch D. , Hanfland C. , Roeske T. , Moran S. B. 
Published: February 2012

The transpolar drift is strongly enriched in 228Ra accumulated on the wide Arctic shelves with subsequent rapid offshore transport. We present new data of Polarstern expeditions to the central Arctic and to the Kara and Laptev seas. Because 226Ra activities in Pacific waters are 30% higher than in Atlantic waters, we correct 226Ra for the Pacific admixture when normalizing 228Ra with 226Ra. The use of 228Ra decay as age marker critically depends on the constancy in space and time of the source activity, a condition that has not yet adequately been tested. While 228Ra decays during transit over the central basin, ingrowth of 228Th could provide an alternative age marker. The high 228Th/228Ra activity ratio (AR = 0.8–1.0) in the central basins is incompatible with a mixing model based on horizontal eddy diffusion. An advective model predicts that 228Th grows to an equilibrium AR, the value of which depends on the scavenging regime. The low AR over the Lomonosov Ridge (AR = 0.5) can be due to either rapid transport (minimum age without scavenging 1.1 year) or enhanced scavenging. Suspended particulate matter load (derived from beam transmission and particulate 234Th) and total 234Th depletion data show that scavenging, although extremely low in the central Arctic, is enhanced over the Lomonosov Ridge, making an age of 3 years more likely. The combined data of 228Ra decay and 228Th ingrowth confirm the existence of a recirculating gyre in the surface water of the eastern Eurasian Basin with a river water residence time of at least 3 years.
Cytosolic Ca2+ regulates the energization of isolated brain mitochondria by formation of pyruvate through the malate–aspartate shuttle
Authors: Gellerich Frank Norbert , Gizatullina Zemfira , Trumbekaite Sonata , Korzeniewski Bernard , Gaynutdinov Timur , Seppet Enn , Vielhaber Stefan , Heinze Hans-Jochen , Striggow Frank 
Published: February 2012

The glutamate-dependent respiration of isolated BM (brain mitochondria) is regulated by Ca2+cyt (cytosolic Ca2+) (S0.5=225±22 nM) through its effects on aralar. We now also demonstrate that the α-glycerophosphate-dependent respiration is controlled by Ca2+cyt (S0.5=60±10 nM). At higher Ca2+cyt (&gt;600 nM), BM accumulate Ca2+ which enhances the rate of intramitochondrial dehydrogenases. The Ca2+-induced increments of state 3 respiration decrease with substrate in the order glutamate&gt;α-oxoglutarate&gt;isocitrate&gt;α-glycerophosphate&gt;pyruvate. Whereas the oxidation of pyruvate is only slightly influenced by Ca2+cyt, we show that the formation of pyruvate is tightly controlled by Ca2+cyt. Through its common substrate couple NADH/NAD+, the formation of pyruvate by LDH (lactate dehydrogenase) is linked to the MAS (malate–aspartate shuttle) with aralar as a central component. A rise in Ca2+cyt in a reconstituted system consisting of BM, cytosolic enzymes of MAS and LDH causes an up to 5-fold enhancement of OXPHOS (oxidative phosphorylation) rates that is due to an increased substrate supply, acting in a manner similar to a ‘gas pedal’. In contrast, Ca2+mit (intramitochondrial Ca2+) regulates the oxidation rates of substrates which are present within the mitochondrial matrix. We postulate that Ca2+cyt is a key factor in adjusting the mitochondrial energization to the requirements of intact neurons.
Mineralogical effects on the detectability of the postperovskite boundary
Authors: Grocholski Brent , Catalli Krystle , Shim Sang-Heon , Prakapenka Vitali 
Published: February 2012

The discovery of a phase transition in Mg-silicate perovskite (Pv) to postperovskite (pPv) at lowermost mantle pressure-temperature (
P
-
T
) conditions may provide an explanation for the discontinuous increase in shear wave velocity found in some regions at a depth range of 200 to 400 km above the core-mantle boundary, hereafter the D
′′
discontinuity. However, recent studies on binary and ternary systems showed that reasonable contents of Fe
2+
and Al for pyrolite increase the thickness (width of the mixed phase region) of the Pv - pPv boundary (400–600 km) to much larger than the D
′′
discontinuity (≤ 70 km). These results challenge the assignment of the D
′′
discontinuity to the Pv - pPv boundary in pyrolite (homogenized mantle composition). Furthermore, the mineralogy and composition of rocks that can host a detectable Pv → pPv boundary are still unknown. Here we report in situ measurements of the depths and thicknesses of the Pv → pPv transition in multiphase systems (San Carlos olivine, pyrolitic, and midocean ridge basaltic compositions) at the
P
-
T
conditions of the lowermost mantle, searching for candidate rocks with a sharp Pv - pPv discontinuity. Whereas the pyrolitic mantle may not have a seismologically detectable Pv → pPv transition due to the effect of Al, harzburgitic compositions have detectable transitions due to low Al content. In contrast, Al-rich basaltic compositions may have a detectable Pv - pPv boundary due to their distinct mineralogy. Therefore, the observation of the D
′′
discontinuity may be related to the Pv → pPv transition in the differentiated oceanic lithosphere materials transported to the lowermost mantle by subducting slabs.
Urinary albumin excretion in heart failure with preserved ejection fraction: an interim analysis of the CHART 2 study
Authors: Miura Masanobu , Shiba Nobuyuki , Nochioka Kotaro , Takada Tsuyoshi , Takahashi Jun , Kohno Haruka , Shimokawa Hiroaki ,   on behalf of the CHART‐2 Investigators
Published: February 2012

AimsHeart failure with preserved ejection fraction (HFpEF) is characterized by multiple co‐morbidities, including chronic kidney disease that is one of the prognostic risks for these patients. This study was performed to evaluate the value of determination of albuminuria using a urine dipstick test (UDT), combined with estimated glomerular filtration rate (eGFR), for predicition of mortality in HFpEF.Methods and resultsWe enrolled 2465 consecutive patients with overt HF with EF ≥50% in our Chronic Heart Failure Analysis and Registry in the Tohoku District 2 (CHART‐2) study (NCT00418041). We defined trace or more UDT as positive. We divided the patients into the following four groups based on eGFR and UDT; group 1 (G1) (eGFR ≥60, negative UDT), G2 (eGFR ≥60, positive UDT), G3 (eGFR <60, negative UDT), and G4 (eGFR <60, positive UDT). In total, 29.5% of the HFpEF patients had a positive UDT. HFpEF patients with a positive UDT were characterized by higher brain natriuretic peptide levels and frequent histories of hypertension or diabetes. During a mean follow‐up of 2.5 years, HFpEF patients with a positive UDT showed higher mortality in each stratum of eGFR levels. A multivariable adjusted Cox model showed that when compared with G1 (reference), the hazard ratio of all‐cause death for G2, G3, and G4 was 2.44 (95% confidence interval 1.47–4.05, P=0.001), 1.43 (0.92–2.23, P=0.12), and 2.71 (1.72–4.27, P<0.001), respectively. Furthermore, the prognostic value of a positive UDT was robust for both cardiovascular and non‐cardiovascular deaths.ConclusionsThese results indicate that measurement of albuminuria in addition to eGFR is useful for appropriate risk stratification in HFpEF patients.