bluuebunny/crossref_metadata_2025 huggingface dataset:
Antiviral Activity of a Small-Molecule Inhibitor of Arenavirus Glycoprotein Processing by the Cellular Site 1 Protease
Authors: Urata Shuzo , Yun Nadezhda , Pasquato Antonella , Paessler Slobodan , Kunz Stefan , de la Torre Juan Carlos
Published: November 2010

Arenaviruses merit interest as clinically important human pathogens and include several causative agents, chiefly Lassa virus (LASV), of hemorrhagic fever disease in humans. There are no licensed LASV vaccines, and current antiarenavirus therapy is limited to the use of ribavirin, which is only partially effective and is associated with significant side effects. The arenavirus glycoprotein (GP) precursor GPC is processed by the cellular site 1 protease (S1P) to generate the peripheral virion attachment protein GP1 and the fusion-active transmembrane protein GP2, which is critical for production of infectious progeny and virus propagation. Therefore, S1P-mediated processing of arenavirus GPC is a promising target for therapeutic intervention. To this end, we have evaluated the antiarenaviral activity of PF-429242, a recently described small-molecule inhibitor of S1P. PF-429242 efficiently prevented the processing of GPC from the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) and LASV, which correlated with the compound's potent antiviral activity against LCMV and LASV in cultured cells. In contrast, a recombinant LCMV expressing a GPC whose processing into GP1 and GP2 was mediated by furin, instead of S1P, was highly resistant to PF-429242 treatment. PF-429242 did not affect virus RNA replication or budding but had a modest effect on virus cell entry, indicating that the antiarenaviral activity of PF-429242 was mostly related to its ability to inhibit S1P-mediated processing of arenavirus GPC. Our findings support the feasibility of using small-molecule inhibitors of S1P-mediated processing of arenavirus GPC as a novel antiviral strategy.
A Transmembrane Serine Protease Is Linked to the Severe Acute Respiratory Syndrome Coronavirus Receptor and Activates Virus Entry
Authors: Shulla Ana , Heald-Sargent Taylor , Subramanya Gitanjali , Zhao Jincun , Perlman Stanley , Gallagher Tom
Published: November 2010

Spike (S) proteins, the defining projections of the enveloped coronaviruses (CoVs), mediate cell entry by connecting viruses to plasma membrane receptors and by catalyzing subsequent virus-cell membrane fusions. The latter membrane fusion requires an S protein conformational flexibility that is facilitated by proteolytic cleavages. We hypothesized that the most relevant cellular proteases in this process are those closely linked to host cell receptors. The primary receptor for the human severe acute respiratory syndrome CoV (SARS) CoV isangiotensin-convertingenzyme2(ACE2). ACE2 immunoprecipitation capturedtransmembraneprotease/serinesubfamily member2(TMPRSS2), a known human airway and alveolar protease. ACE2 and TMPRSS2 colocalized on cell surfaces and enhanced the cell entry of both SARS S-pseudotyped HIV and authentic SARS-CoV. Enhanced entry correlated with TMPRSS2-mediated proteolysis of both S and ACE2. These findings indicate that a cell surface complex comprising a primary receptor and a separate endoprotease operates as a portal for activation of SARS-CoV cell entry.
Classification of 17 newly isolated virulent bacteriophages of Pseudomonas aeruginosa
Authors: Li Lingyan , Yang Hongjiang , Lin Shuxiang , Jia Shiru
Published: November 2010

Seventeen virulent bacteriophages specific to Pseudomonas aeruginosa strains were isolated by screening various environmental samples. These isolated bacteriophages were grouped based on results obtained from restriction fragment analysis of phage genomes, random amplification of polymorphic DNA (RAPD) typing, morphology observations under transmission electron microscope, and host range analysis. All 17 bacteriophages are double-stranded DNA viruses and can be divided into 5 groups based on DNA restriction profiles. A set of 10-mer primers was used in RAPD typing of phages, and similar conclusions were obtained as for restriction fragment analysis. One phage was randomly selected from each of the 5 groups for morphology observations. Four of them had an icosahedral head with a long contractile tail, belonging to the Myoviridae family, and one phage had an icosahedral head with a short tail, thereby belonging to the Podoviridae family. Host range experiments were conducted on 7 laboratory strains and 12 clinical strains of P. aeruginosa. The results showed that 13 phages had the same infection profile, killing 8 out of 19 tested P. aeruginosa strains, and the remaining 4 phages had different and unique infection profiles. This study highlights the diversity of bacteriophages specific to P. aeruginosa in the environment.
Microbiological quality of blue mussels (Mytilus edulis) in Nunavik, Quebec: a pilot study
Authors: Lévesque Benoît , Barthe Christine , Dixon Brent R. , Parrington Lorna J. , Martin Daniel , Doidge Bill , Proulx Jean-François , Murphy Donald
Published: November 2010

This pilot study was aimed at documenting the presence of fecal indicators and enteric pathogens in blue mussels ( Mytilus edulis ) from 6 communities in Nunavik, Quebec. One to four 2 kg samples of mussels were collected at low tide in each community. Samples were investigated by enumeration methods for the fecal indicators enterococci, Escherichia coli , F-specific coliphages, Clostridium perfringens , and by molecular identification for the pathogens norovirus, Salmonella spp., Campylobacter jejuni , Campylobacter coli , and Campylobacter lari , verocytotoxin-producing E. coli (particularly serovar O157:H7), Shigella spp., and Yersinia enterocolitica . In 5 communities, the presence of Giardia duodenalis and Cryptosporidium spp. was also tested by microscopy and molecular methods and that of Toxoplasma gondii was tested by molecular methods. Apart from small quantities of Clostridium perfringens in 2 samples, no bacterial or viral pathogens were detected in the mussels. Toxoplasma gondii was also not detected. However, G. duodenalis and Cryptosporidium spp. were present in 18% and 73% of the samples investigated for these pathogens, respectively. When considering the indicators and the viral and bacterial pathogens investigated, the mussels examined were of good microbiological quality, but considering the presence of potentially zoonotic protozoa, it should be recommended that consumers cook the molluscs well before eating them.
Hemolytic phospholipaseRv0183of Mycobacterium tuberculosis induces inflammatory response and apoptosis in alveolar macrophage RAW264.7 cells
Authors: Xu Guangxian , Jia Hao , Li Yong , Liu Xiaoming , Li Min , Wang Yujiong
Published: November 2010

The metabolic pathway of phospholipids is one of the most important physiologic pathways in Mycobacterium tuberculosis , a typical intracellular bacterium. The hemolytic phospholipase lip gene (Rv0183) is one of 24 phospholipase genes that have been demonstrated to play critical roles in the metabolism of phospholipids in M. tuberculosis. Quantitative RT–PCR and flow cytometry were used to elucidate the immunological and pathogenic implications of the Rv0183 gene on the inflammatory response following persistent expression of Rv0183 in mouse alveolar macrophage RAW264.7 cells. Our results demonstrate that a time-course-dependent ectopic expression of Rv0183 significantly elevated the expression of IL-6, NF-κB, TLR-2, TLR-6, TNFα, and MyD88 in these alveolar macrophage cells. Furthermore, the persistent expression of Rv0183 induced RAW264.7 cell apoptosis in vitro. These findings demonstrate that the expression of Rv0183 induces an inflammatory response and cell apoptosis in the host cells, suggesting that Rv0183 may play an important role in the virulence and pathogenesis of M. tuberculosis infection.
Verticillium dahliaealtersPseudomonasspp. populations and HCN gene expression in the rhizosphere of strawberry
Authors: DeCoste Nadine J. , Gadkar Vijay J. , Filion Martin
Published: November 2010

The production of hydrogen cyanide (HCN) by beneficial root-associated bacteria is an important mechanism for the biological control of plant pathogens. However, little is known about the biotic factors affecting HCN gene expression in the rhizosphere of plants. In this study, real-time reverse transcription PCR (qRT–PCR) assays were developed to investigate the effect of the plant pathogen Verticillium dahliae on hcnC (encoding for HCN biosynthesis) gene expression in Pseudomonas sp. LBUM300. Strawberry plants were inoculated with Pseudomonas sp. LBUM300 and (or) V. dahliae and grown in pots filled with nonsterilized field soil. RNA was extracted from rhizosphere soil sampled at 0, 15, 30, and 45 days following inoculation with V. dahliae and used for qRT–PCR analyses. Populations of V. dahliae and Pseudomonas sp. LBUM300 were also monitored using a culture-independent qPCR approach. hcnC expression was detected at all sampling dates. The presence of V. dahliae had a significant stimulation effect on hcnC gene expression and also increased the population of Pseudomonas sp. LBUM300. However, the V. dahliae population was not altered by the presence of Pseudomonas sp. LBUM300. To our knowledge, this study is the first to evaluate the effect of a plant pathogen on HCN gene expression in the rhizosphere soil.
Characterization of a thioredoxin (BbTrx) from the entomopathogenic fungus Beauveria bassiana and its expression in response to thermal stress
Authors: Ying Sheng-Hua , Wang Xiao-Hui , Feng Ming-Guang
Published: November 2010

A thioredoxin (BbTrx) was identified from the entomopathogenic fungus Beauveria bassiana . The cloned nucleotide sequence consisted of a 423-bp open reading frame encoding a 141-amino-acid thioredoxin, a 1011-bp 5′ region, and a 419-bp 3′ region. The deduced protein sequence of BbTrx, including a common 95-amino-acid conserved domain and a unique 46-amino-acid carboxy terminal region, was similar (≤38% identity) to that of other thioredoxins and phylogenetically closest to that from Neurospora crassa . In insulin solution containing dithiothreitol at 25 °C, recombinant BbTrx or a truncated form lacking the carboxy terminal region (BbTrxD) exhibited disulfide reduction activity. BbTrxD was more active after pre-incubation at 40–75 °C, and cells expressing BbTrxD showed significantly higher tolerance to thermal stress (51 °C). The BbTrx expression in B. bassiana was greatly elevated when stressed at 40 °C. The results indicate that the new thioredoxin is a potential target for improving the thermotolerance of B. bassiana formulations.
Comparison of microbial diversity of edible flowers and basil grown with organic versus conventional methods
Authors: Wetzel Kaedra , Lee Jiyoung , Lee Chang Soo , Binkley Margaret
Published: November 2010

The consumption and use of edible flowers as food is growing; however, no study has been conducted to evaluate their role in the cause of food-borne illness or in food safety. Recent food-borne outbreaks traced to fresh herbs have raised concern about their processing and handling. Basil, one of the most commonly used fresh herbs, has been identified as a source of food-borne illness. Baseline assessments of microflora were performed, and the microbial diversity between growing methods (organic vs. conventional) was compared. DNA sequencing was used to identify the microbial flora present on fresh edible flower and basil samples. The most predominant species identified were Enterobacter hormaechei (10%), Acinetobacter calcoaceticus (10%), Enterobacter ludwigii (10%), Enterobacter asburiae (6%), and Enterobacter cowanii (6%). Pseudomonas aeruginosa (6%), Salmonella enterica (6%), and Bacillus amyloliquefaciens (2%) were also isolated. Phylogenetic analysis showed that most species of isolated bacteria belonged to the phyla Gammaproteobacteria (81.2%) and Firmicutes (18.8%). Statistical analysis, diversity index for species richness, and lineage-per-time plots showed that for basil, organically grown samples had a higher microbial diversity than conventionally grown samples. Edible flowers and basil are often grown using organic methods and are commonly consumed raw without any washing or cooking, to preserve aesthetic value, but these practices may pose a potential risk for food-borne illness. The baseline assessment, together with phylogenetic and statistical analyses, indicated possible microbial contamination in edible flowers and basil. The use of statistical estimation of molecular diversity based on the 16S rRNA sequences and lineage-per-time plots with phylogenetic analysis well served as a means for comparing microbial diversity in food samples between the growing methods (organic vs. conventional).
Effect of the cortex-lytic enzyme SleC from non-food-borne Clostridium perfringens on the germination properties of SleC-lacking spores of a food poisoning isolate
Authors: Paredes-Sabja Daniel , Sarker Mahfuzur R.
Published: November 2010

The hallmark of bacterial spore germination is peptidoglycan cortex hydrolysis by cortex-lytic enzymes. In spores of Clostridium perfringens wild-type strain SM101, which causes food poisoning, the sole essential cortex-lytic enzyme SleC is activated by a unique serine protease CspB. Interestingly, the non-food-borne wild-type strain F4969 encodes a significantly divergent SleC variant (SleCF4969) and 3 serine proteases (CspA, CspB, and CspC). Consequently, in this study we evaluated the functional compatibility of SleCF4969and SleCSM101by complementing the germination phenotypes of SM101ΔsleC spores with sleCF4969. Our results show that although pro-SleCF4969was processed into mature SleCF4969in the SM101ΔsleC spores, it partially restored spore germination with nutrient medium, with a mixture of l-asparagine and KCl, or with a 1:1 chelate of Ca2+and dipicolinic acid. While the amount of dipicolinic acid released was lower, the amount of hexosamine-containing material released during germination of SM101ΔsleC(sleCF4969) spores was similar to the amount released during germination of SM101 wild-type spores. The viability of SM101ΔsleC(sleCF4969) spores was 8- and 3-fold lower than that of SM101 and F4969 spores, respectively. Together, these data indicate that the peptidoglycan cortex hydrolysis machinery in the food poisoning isolate SM101 is functionally divergent than that in the non-food-borne isolate F4969.
Effect of simvastatin on collagen I deposition in non-infarcted myocardium: role of NF-κB and osteopontin
Authors: Zhang Jianhua , Xu Yan , Pan Lingxin , Chen Ting , Chen Zhiwu , Zhao Ren
Published: November 2010

The novel biological effect of statins in alleviating myocardium fibrosis following infarction has been increasingly recognized, yet the underlying mechanisms are not fully understood. The purpose of this study was to characterize the effect of simvastatin on myocardial fibrosis and collagen I deposition in the non-infarcted region after myocardial infarction (MI) and to identify the role of NF-κB and osteopontin in simvastatin-mediated inhibition of post-MI collagen over-expression. A rat model of MI was generated by ligating the left anterior descending coronary artery. The rats surviving the MI operation were randomly divided into the following 3 groups: myocardial infarction (MI, vehicle), simvastatin (Sim, 30 mg·kg–1·day–1), and pyrrolidine dithiocarbamate (PDTC, an inhibitor of NF-κB, 100 mg·kg–1·day–1). Four weeks after MI, cardiac function, mRNAs, and protein expression in non-infarcted myocardium were analyzed. Myocardial fibrosis and collagen I over-expression were observed following MI, accompanied by an increase of NF-κB and osteopontin. Simvastatin improved post-MI left ventricular dysfunction and ameliorated post-MI associated changes to several cardiac parameters, including the left ventricular end diastolic pressure (LVEDP), the maximal rate of pressure development (+dP/dtmax), and the maximal rate of pressure decline (–dP/dtmax). Concurrently, simvastatin significantly suppressed the over-expression of NF-κB, osteopontin, and collagen I in the non-infarcted region following MI. Inhibition of NF-κB by PDTC also reduced osteopontin over-expression and excessive collagen I production and improved the above functional myocardial parameters. These results show that post-MI myocardial fibrosis and collagen I over-expression in the non-infarcted region is associated with activation of NF-κB and osteopontin up-regulation. The anti-fibrotic effect of simvastatin following MI is associated with the attenuation of the expression of osteopontin and NF-κB. The inhibition of NF-κB activation could be the process upstream of osteopontin suppression in the simvastatin-mediated effect.
Effects of Longevinex (modified resveratrol) on cardioprotection and its mechanisms of action
Authors: Mukherjee Subhendu , Ray Diptarka , Lekli Istvan , Bak Istvan , Tosaki Arpad , Das Dipak K.
Published: November 2010

Although resveratrol has been proven to possess diverse health benefits, several recent reports have demonstrated conflicting results on some aspects of its effects, including its anti-aging properties. Considerable debate appears to exist on the dose and bioavailability of resveratrol, leading to the controversies on its effectiveness. To resolve the problem, we designed a study with a resveratrol formulation that contained resveratrol supplemented with 5% quercetin and 5% rice bran phytate (commercially known as Longevinex). These ingredients were micronized to increase the bioavailability. Sprague–Dawley rats were gavaged with either Longevinex or vehicle (5% quercetin plus 5% rice bran phytate), and rats were sacrificed after 1 or 3 months, when isolated working hearts were subjected to 30 min ischemia followed by 2 h of reperfusion. Longevinex-treated hearts, irrespective of the duration of treatments, revealed superior cardiac performance, reduced infarct size, and induction of survival signals as evidenced by increased Bcl2/Bax ratio and enhanced Akt phosphorylation. In contrast, LC3-II and Beclin were enhanced significantly after 3 months of Longevinex treatment, suggesting that autophagy occurred only after feeding Longevinex to rats for a prolonged period of time. Corroborating with the results of autophagy, Sirt1 and Sirt3 increased significantly only after 3 months of Longevinex treatment, suggesting that enhanced expression of Sirts correlated with induction of autophagy. In concert, Longevinex caused phosphorylation and nuclear translocation of FoxO1, FoxO3a, and FoxO4, indicating involvement of FoxOs with autophagy. Since Sirts and FoxOs are reliable markers of longevity, the results appear to suggest that Longevinex induces longevity after prolonged feeding via induction of autophagy, while it converts death signals into survival signals and provides cardioprotection within a relatively shorter period of time.
Ipomoea obscura ameliorates cyclophosphamide-induced toxicity by modulating the immune system and levels of proinflammatory cytokine and GSH
Authors: Hamsa T. P. , Kuttan Girija
Published: November 2010

Ipomoea obscura L. is a widely used medicinal plant. The objective of this study was to investigate its protective activity against cyclophosphamide (CTX)-induced toxicity in mouse models. Swiss albino mice were treated intraperitoneally with CTX (25 mg/kg body weight) along with I. obscura extract (10 mg/kg body weight) for 10 days. Extract significantly reduced myelosuppression caused by CTX and improved the relative organ weight, total white blood cell count, and bone marrow cellularity. The elevated levels of parameters related to pathophysiology of the liver, namely glutamate pyruvate transaminase, alkaline phosphatase, and lipid peroxidation, were significantly reduced by extract treatment. Reduction of liver and intestinal glutathione levels of CTX-treated animals was reversed by I. obscura. The lowered levels of cytokines, namely IFN-γ, IL-2, and granulocyte–monocyte colony-stimulating factor after CTX treatment were found to be increased in I. obscura treated animals. Treatment with I. obscura could also decrease the level of proinflammatory cytokine TNF-α. The data suggested that I. obscura can act as a potent chemoprotective agent and can be used as an adjuvant in chemotherapeutic applications.
Habitat use by female western roe deer (Capreolus capreolus): influence of resource availability on habitat selection in two contrasting years
Authors: Pellerin M. , Calenge C. , Saïd S. , Gaillard J.- M. , Fritz H. , Duncan P. , Van Laere G.
Published: November 2010

In most previous studies of habitat selection, the use of a given habitat type is assumed to be directly proportional to its availability. However, the use and (or) the selection of a given habitat may be conditional on the availability of that habitat. We aim here to (i) identify the environmental variables involved in habitat selection, (ii) identify classes of individuals with similar patterns of habitat selection, and (iii) assess whether habitat use changes with changing availability of habitat types, within monthly home ranges of female western roe deer ( Capreolus capreolus (L., 1758)). We found that some females adjust their habitat use according to the distribution of resources within habitats. Females with similar home ranges in terms of resource quantity and quality showed similar patterns of habitat selection. Differences in habitat use between 2 years with contrasting resource availability showed that temporal changes of environmental conditions influenced the pattern of habitat selection by female roe deer. Habitat selection also differed between periods of the life cycle likely because of contrasted energy requirements. This study shows that the relationship between habitat use by herbivores and habitat availability is nonproportional, and that the availability of resources influences use mostly at intermediate values.
A distance-based analysis of habitat selection by American black bears (Ursus americanus) on the Bruce Peninsula, Ontario, Canada
Authors: Obbard Martyn E. , Coady Melissa B. , Pond Bruce A. , Schaefer James A. , Burrows Frank G.
Published: November 2010

Because of their wide-ranging habits, conserving large carnivores such as American black bears ( Ursus americanus Pallas, 1780) often depends on understanding habitat needs beyond the boundary of protected areas. We studied habitat selection by black bears in the vicinity of Bruce Peninsula National Park, Ontario — a small, isolated population whose persistence appears dependent on habitat on lands outside the Park. We used an approach based on Euclidean distances to document seasonal habitat selection at two spatial scales and to identify candidate habitat types for protection. Adult females selected dense mixed forests to establish home ranges within the population range, whereas subadults and yearlings selected dense deciduous forests. Within home ranges, adults selected dense mixed forest in spring–summer and dense deciduous forest in late summer – fall. Subadults selected dense deciduous forest, marsh, dense mixed forest, and water during the spring–summer and avoided developed lands and roads. Yearlings selected dense mixed forest, dense deciduous forest, and sparse forests in spring–summer and dense deciduous forest and dense mixed forest in late summer – fall. The selection of dense deciduous and dense mixed forest stands, especially at the broader scale, suggests that strategies to ensure persistence of this isolated population should focus on protecting the integrity of these stands.
Thermal environments of overwintering Eastern Box Turtles (Terrapene carolina carolina)
Authors: Savva Yulia , Swarth Christopher W. , Gupchup Jayant , Szlavecz Katalin
Published: November 2010

Using a mixed-effects model for 21 Eastern Box Turtles ( Terrapene carolina carolina (L., 1758)) over three winters in Maryland, USA, we demonstrate that overwintering-site temperature was mainly related to air temperature. After controlling for air temperature, between-year variation accounted for 7%, between-turtle variation accounted for 3%, and variation owing to age class accounted for 1% of the total variation in overwintering-site temperature. Turtles showed overwintering-site fidelity and the location of overwintering sites did not depend on sex or age. According to the developed function, air temperature would have to increase by 3 °C over the overwintering period to raise the temperature of overwintering sites by about 1 °C, assuming no changes in other environmental factors; this level of warming is not expected until 2070–2090 according to general climate circulation models.
The diving behaviour of mammal-eating killer whales (Orcinus orca): variations with ecological not physiological factors
Authors: Miller Patrick James O’Malley , Shapiro Ari Daniel , Deecke Volker Bernt
Published: November 2010

Mammal-eating killer whales ( Orcinus orca (L., 1758)) are a rare example of social predators that hunt together in groups of sexually dimorphic adults and juveniles with diverse physiological diving capacities. Day–night ecological differences should also affect diving as their prey show diel variation in activity and mammal-eating killer whales do not rely on echolocation for prey detection. Our objective was to explore the extent to which physiological aerobic capacities versus ecological factors shape the diving behaviour of this breath-hold diver. We used suction-cup-attached depth recorders (Dtags) to record 7608 dives of 11 animals in southeast Alaska. Analysis of dive sequences revealed a strong bout structure in both dive depth and duration. Day–night comparisons revealed reduced rates of deep dives, longer shallow dives, and shallower long-duration dives at night. In contrast, dive variables did not differ by age–sex class. Estimates of the aerobic dive limit (cADL) suggest that juveniles exceeded their cADL during as much as 15% of long dives, whereas adult males and females never exceeded their cADL. Mammal-eating killer whales in this area appear to employ a strategy of physiological compromise, with smaller group members diving nearer their physiological limits and large-bodied males scaling down their physiological performance.
Nutrient allocation for egg production in six Atlantic seabirds
Authors: Bond Alexander L. , Diamond Antony W.
Published: November 2010

How species allocate nutrients to egg production is an important question in contaminant analyses. Seabird eggs are sampled frequently in such studies, so it is important to know the source of nutrients in these eggs if the source of the contaminants is to be traced. We used a stable-isotope approach to evaluate the relative importance of locally derived nutrients (income breeding) and stored nutrient reserves (capital breeding) in six species of Atlantic seabirds (Arctic Tern, Sterna paradisaea Pontoppidan, 1763; Common Tern, Sterna hirundo L., 1758; Atlantic Puffin, Fratercula arctica (L., 1758); Common Murre, Uria aalge (Pontoppidan, 1763); Razorbill, Alca torda L., 1758; Leach’s Storm-Petrel, Oceanodroma leucorhoa (Vieillot, 1818)) breeding in the Bay of Fundy. We found that all species either were income breeders or adopted an intermediate strategy whereby varying proportions of locally derived nutrients were incorporated into eggs. Each species’ migratory behaviour is likely a main factor in determining the amount of endogenous nutrients used in egg formation.
DEFORMABLE QUANTUM INDUCTANCE (RING) INTERACTING WITH A PHONON FIELD: PERSISTENT ELECTRICAL CURRENTS RE-VISITED ((qe/ℏ) VERSUS (2qe/ℏ))
Authors: CALCINA M. , FLORES J. C.
Published: November 2010

The Hamiltonian of a flexible purely inductive quantum circuits, with discrete charge (qe), coupled to the vibrational degrees of a lattice (phonons) is presented. In the static regime, when the inductance is threaded by an external fixed magnetic flux, the usual periodic behavior in the persistent electrical current (frequency qe/ℏ) becomes altered. A new harmonic appears which is twice that of the fundamental (2qe/ℏ). All this is the consequence of the geometric static deformation in the inductance produced by the persistent electrical current itself (Lorentz force).
STRUCTURE AND MAGNETIC PROPERTIES OF MANGANESE OXIDE NANOPARTICLES PREPARED BY ARC SUBLIMATION
Authors: SI P. Z. , WANG H. X. , JIANG W. , LEE J. G. , CHOI C. J. , SOHNEL T.
Published: November 2010

Manganese oxide nanoparticles with narrow size distribution were prepared in large scale by arc sublimation of bulk MnO . Although MnO is antiferromagnetic, the as-prepared manganese oxide nanoparticles exhibit ferromagnetic behaviors with coercivity and exchange bias up to 417,065 A/m and 162,099 A/m at 5 K, respectively. We attribute these anomalous magnetic properties to the presence of ferrimagnetic Mn 3 O 4, uncompensated surface spins and their coupling to the antiferromagnetic MnO .
MATCHING PRECLUSION AND CONDITIONAL MATCHING PRECLUSION FOR AUGMENTED CUBES
Authors: CHENG EDDIE , JIA RANDY , LU DAVID
Published: November 2010

The matching preclusion number of a graph is the minimum number of edges whose deletion results in a graph that has neither perfect matchings nor almost-perfect matchings. For many interconnection networks, the optimal sets are precisely those incident to a single vertex. Recently, the conditional matching preclusion number of a graph was introduced to look for obstruction sets beyond those incident to a single vertex. It is defined to be the minimum number of edges whose deletion results in a graph with no isolated vertices that has neither perfect matchings nor almost-perfect matchings. In this paper, we find this number and classify all optimal sets for the augmented cubes, a class of networks designed as an improvement of the hypercubes.
Cell physiology at the Mount Desert Island Biological Laboratory: a brief look back and forward
Authors: Strange Kevin
Published: November 2010

The Mount Desert Island Biological Laboratory (MDIBL) has played important roles in the development of modern physiological concepts and tools, particularly in the fields of kidney and epithelial cell physiology. Over the last decade, MDIBL has undergone remarkable growth and evolution. This article will briefly review MDIBL's past and outline its future directions. It is hoped that this overview will renew and stimulate interest in MDIBL and, in particular, will encourage an even wider community of physiologists to participate in its ongoing growth and development.
Paracrine modulation of cholangiocyte serotonin synthesis orchestrates biliary remodeling in adults
Authors: Omenetti Alessia , Yang Liu , Gainetdinov Raul R. , Guy Cynthia D. , Choi Steve S. , Chen Wei , Caron Marc G. , Diehl Anna Mae
Published: November 2010

Paracrine signaling between cholangiocytes and stromal cells regulates biliary remodeling. Cholangiocytes have neuroepithelial characteristics and serotonin receptor agonists inhibit their growth, but whether they are capable of serotonin biosynthesis is unknown. We hypothesized that cholangiocytes synthesize serotonin and that cross talk between liver myofibroblasts (MF) and cholangiocytes regulates this process to influence biliary remodeling. Transwell cultures of cholangiocytes ± MF, and tryptophan hydroxylase-2 knockin (TPH2KI) mice with an inactivating mutation of the neuronal tryptophan hydroxylase (TPH) isoform, TPH2, were evaluated. Results in the cell culture models confirm that cholangiocytes have serotonin receptors and demonstrate for the first time that these cells express TPH2 and produce serotonin, which autoinhibits their growth but stimulates MF production of TGF-β1. Increased TGF-β1, in turn, counteracts autocrine inhibition of cholangiocyte growth by repressing cholangiocyte TPH2 expression. Studies of TPH2KI mice confirm that TPH2-mediated production of serotonin plays an important role in remodeling damaged bile ducts because mice with decreased TPH2 function have reduced biliary serotonin levels and exhibit excessive cholangiocyte proliferation, accumulation of aberrant ductules and liver progenitors, and increased liver fibrosis after bile duct ligation. This new evidence that cholangiocytes express the so-called neuronal isoform of TPH, synthesize serotonin de novo, and deploy serotonin as an autocrine/paracrine signal to regulate regeneration of the biliary tree complements earlier work that revealed that passive release of serotonin from platelets stimulates hepatocyte proliferation. Given the prevalent use of serotonin-modulating drugs, these findings have potentially important implications for recovery from various types of liver damage.
Fructose-maltodextrin ratio in a carbohydrate-electrolyte solution differentially affects exogenous carbohydrate oxidation rate, gut comfort, and performance
Authors: O'Brien Wendy J. , Rowlands David S.
Published: November 2010

Solutions containing multiple carbohydrates utilizing different intestinal transporters (glucose and fructose) show enhanced absorption, oxidation, and performance compared with single-carbohydrate solutions, but the impact of the ratio of these carbohydrates on outcomes is unknown. In a randomized double-blind crossover, 10 cyclists rode 150 min at 50% peak power, then performed an incremental test to exhaustion, while ingesting artificially sweetened water or one of three carbohydrate-salt solutions comprising fructose and maltodextrin in the respective following concentrations: 4.5 and 9% (0.5-Ratio), 6 and 7.5% (0.8-Ratio), and 7.5 and 6% (1.25-Ratio). The carbohydrates were ingested at 1.8 g/min and naturally 13C-enriched to permit evaluation of oxidation rate by mass spectrometry and indirect calorimetry. Mean exogenous carbohydrate oxidation rates were 1.04, 1.14, and 1.05 g/min (coefficient of variation 20%) in 0.5-, 0.8-, and 1.25-Ratios, respectively, representing likely small increases in 0.8-Ratio of 11% (90% confidence limits; ±4%) and 10% (±4%) relative to 0.5- and 1.25-Ratios, respectively. Comparisons of fat and total and endogenous carbohydrate oxidation rates between solutions were unclear. Relative to 0.5-Ratio, there were moderate improvements to peak power with 0.8- (3.6%; 99% confidence limits ± 3.5%) and 1.25-Ratio (3.0%; ±3.7%) but unclear with water (0.4%; ±4.4%). Increases in stomach fullness, abdominal cramping, and nausea were lowest with the 0.8- followed by the 1.25-Ratio solution. At high carbohydrate-ingestion rate, greater benefits to endurance performance may result from ingestion of 0.8- to 1.25-Ratio fructose-maltodextrin solutions. Small perceptible improvements in gut comfort favor the 0.8-Ratio and provide a clearer suggestion of mechanism than the relationship with exogenous carbohydrate oxidation.
Mechanisms of reflex bladder activation by pudendal afferents
Authors: Woock John P. , Yoo Paul B. , Grill Warren M.
Published: November 2010

Activation of pudendal afferents can evoke bladder contraction or relaxation dependent on the frequency of stimulation, but the mechanisms of reflex bladder excitation evoked by pudendal afferent stimulation are unknown. The objective of this study was to determine the contributions of sympathetic and parasympathetic mechanisms to bladder contractions evoked by stimulation of the dorsal nerve of the penis (DNP) in α-chloralose anesthetized adult male cats. Bladder contractions were evoked by DNP stimulation only above a bladder volume threshold equal to 73 ± 12% of the distension-evoked reflex contraction volume threshold. Bilateral hypogastric nerve transection (to eliminate sympathetic innervation of the bladder) or administration of propranolol (a β-adrenergic antagonist) decreased the stimulation-evoked and distension-evoked volume thresholds by −25% to −39%. Neither hypogastric nerve transection nor propranolol affected contraction magnitude, and robust bladder contractions were still evoked by stimulation at volume thresholds below the distension-evoked volume threshold. As well, inhibition of distention-evoked reflex bladder contractions by 10 Hz stimulation of the DNP was preserved following bilateral hypogastric nerve transection. Administration of phentolamine (an α-adrenergic antagonist) increased stimulation-evoked and distension-evoked volume thresholds by 18%, but again, robust contractions were still evoked by stimulation at volumes below the distension-evoked threshold. These results indicate that sympathetic mechanisms contribute to establishing the volume dependence of reflex contractions but are not critical to the excitatory pudendal to bladder reflex. A strong correlation between the magnitude of stimulation-evoked bladder contractions and bladder volume supports that convergence of pelvic afferents and pudendal afferents is responsible for bladder excitation evoked by pudendal afferents. Further, abolition of stimulation-evoked bladder contractions following administration of hexamethonium bromide confirmed that contractions were generated by pelvic efferent activation via the pelvic ganglion. These findings indicate that pudendal afferent stimulation evokes bladder contractions through convergence with pelvic afferents to increase pelvic efferent activity.
O-GlcNAcylation: a novel pathway contributing to the effects of endothelin in the vasculature
Authors: Lima Victor V. , Giachini Fernanda R. , Hardy David M. , Webb R. Clinton , Tostes Rita C.
Published: November 2010

Glycosylation with O-linked β- N-acetylglucosamine ( O-GlcNAc) or O-GlcNAcylation on serine and threonine residues of nuclear and cytoplasmic proteins is a posttranslational modification that alters the function of numerous proteins important in vascular function, including kinases, phosphatases, transcription factors, and cytoskeletal proteins. O-GlcNAcylation is an innovative way to think about vascular signaling events both in physiological conditions and in disease states. This posttranslational modification interferes with vascular processes, mainly vascular reactivity, in conditions where endothelin-1 (ET-1) levels are augmented (e.g. salt-sensitive hypertension, ischemia/reperfusion, and stroke). ET-1 plays a crucial role in the vascular function of most organ systems, both in physiological and pathophysiological conditions. Recognition of ET-1 by the ETAand ETBreceptors activates intracellular signaling pathways and cascades that result in rapid and long-term alterations in vascular activity and function. Components of these ET-1-activated signaling pathways (e.g., mitogen-activated protein kinases, protein kinase C, RhoA/Rho kinase) are also targets for O-GlcNAcylation. Recent experimental evidence suggests that ET-1 directly activates O-GlcNAcylation, and this posttranslational modification mediates important vascular effects of the peptide. This review focuses on ET-1-activated signaling pathways that can be modified by O-GlcNAcylation. A brief description of the O-GlcNAcylation biology is presented, and its role on vascular function is addressed. ET-1-induced O-GlcNAcylation and its implications for vascular function are then discussed. Finally, the interplay between O-GlcNAcylation and O-phosphorylation is addressed.
Transgenic mice: beyond the knockout
Authors: Miller R. Lance
Published: November 2010

Transgenic mice have had a tremendous impact on biomedical research. Most researchers are familiar with transgenic mice that carry Cre recombinase (Cre) and how they are used to create conditional knockouts. However, some researchers are less familiar with many of the other types of transgenic mice and their applications. For example, transgenic mice can be used to study biochemical and molecular pathways in primary cultures and cell suspensions derived from transgenic mice, cell-cell interactions using multiple fluorescent proteins in the same mouse, and the cell cycle in real time and in the whole animal, and they can be used to perform deep tissue imaging in the whole animal, follow cell lineage during development and disease, and isolate large quantities of a pure cell type directly from organs. These novel transgenic mice and their applications provide the means for studying of molecular and biochemical events in the whole animal that was previously limited to cell cultures. In conclusion, transgenic mice are not just for generating knockouts.
Differential Effects of Axon Initial Segment and Somatodendritic GABAAReceptors on Excitability Measures in Rat Dentate Granule Neurons
Authors: Rojas Patricio , Akrouh Alejandro , Eisenman Lawrence N. , Mennerick Steven
Published: November 2010

GABAAreceptors are found on the somatodendritic compartment and on the axon initial segment of many principal neurons. The function of axonal receptors remains obscure, although it is widely assumed that axonal receptors must have a strong effect on excitability. We found that activation of GABAAreceptors on the dentate granule neuron axon initial segment altered excitability by depolarizing the voltage threshold for action potential initiation under conditions that minimally affected overall cell input resistance. In contrast, activation of somatic GABAAreceptors strongly depressed the input resistance of granule neurons without affecting the voltage threshold of action potential initiation. Although these effects were observed over a range of intracellular chloride concentrations, average voltage threshold was unaffected when EClrendered GABAAaxon initial segment responses explicitly excitatory. A compartment model of a granule neuron confirmed these experimental observations. Low ambient agonist concentrations designed to activate granule neuron tonic currents did not stimulate axonal receptors sufficiently to raise voltage threshold. Using excitatory postsynaptic current (EPSC)-like depolarizations, we show physiological consequences of axonal versus somatic GABAAreceptor activation. With axonal inhibition, individual excitatory postsynaptic potentials (EPSPs) largely retained their amplitude and time course, but EPSPs that were suprathreshold under basal conditions failed to reach threshold with GABAAactivation. By contrast, somatic inhibition depressed individual EPSPs because of strong shunting. Our results suggest that axonal GABAAreceptors have a privileged effect on voltage threshold and that two major measures of neuronal excitability, voltage threshold and rheobase, are differentially affected by axonal and somatic GABAAreceptor activation.
Characteristics of Calcium Currents in Rat Geniculate Ganglion Neurons
Authors: Nakamura Shiro , Bradley Robert M.
Published: November 2010

Geniculate ganglion (GG) cell bodies of chorda tympani (CT), greater superficial petrosal (GSP), and posterior auricular (PA) nerves transmit orofacial sensory information to the rostral nucleus of the solitary tract (rNST). We used whole cell recording to study the characteristics of the Ca2+ channels in isolated Fluorogold-labeled GG neurons that innervate different peripheral receptive fields. PA neurons were significantly larger than CT and GSP neurons, and CT neurons could be further subdivided based on soma diameter. Although all GG neurons possess both low voltage–activated (LVA) “T-type” and high voltage–activated (HVA) Ca2+ currents, CT, GSP, and PA neurons have distinctly different Ca2+ current expression patterns. Of GG neurons that express T-type currents, the CT and GSP neurons had moderate and PA neurons had larger amplitude T-type currents. HVA Ca2+ currents in the GG neurons were separated into several groups using specific Ca2+ channel blockers. Sequential applications of L, N, and P/Q-type channel antagonists inhibited portions of Ca2+ current in all CT, GSP, and PA neurons to a different extent in each neuron group. No difference was observed in the percentage of L- and N-type Ca2+ currents reduced by the antagonists in CT, GSP, and PA neurons. Action potentials in GG neurons are followed by a Ca2+ current initiated afterdepolarization (ADP) that may influence intrinsic firing patterns. These results show that based on Ca2+ channel expression the GG contains a heterogeneous population of sensory neurons possibly related to the type of sensory information they relay to the rNST.
Developmental Nicotine Exposure Alters Neurotransmission and Excitability in Hypoglossal Motoneurons
Authors: Pilarski Jason Q. , Wakefield Hilary E. , Fuglevand Andrew J. , Levine Richard B. , Fregosi Ralph F.
Published: November 2010

Hypoglossal motoneurons (XII MNs) control muscles of the mammalian tongue and are rhythmically active during breathing. Acetylcholine (ACh) modulates XII MN activity by promoting the release of glutamate from neurons that express nicotinic ACh receptors (nAChRs). Chronic nicotine exposure alters nAChRs on neurons throughout the brain, including brain stem respiratory neurons. Here we test the hypothesis that developmental nicotine exposure (DNE) reduces excitatory synaptic input to XII MNs. Voltage-clamp experiments in rhythmically active medullary slices showed that the frequency of excitatory postsynaptic currents (EPSCs) onto XII MNs from DNE animals is reduced by 61% (DNE = 1.7 ± 0.4 events/s; control = 4.4 ± 0.6 events/s; P < 0.002). We also examine the intrinsic excitability of XII MNs to test whether cells from DNE animals have altered membrane properties. Current-clamp experiments showed XII MNs from DNE animals had higher intrinsic excitability, as evaluated by measuring their response to injected current. DNE cells had high-input resistances (DNE = 131.9 ± 13.7 MΩ, control = 78.6 ± 9.7 MΩ, P < 0.008), began firing at lower current levels (DNE = 144 ± 22 pA, control = 351 ± 45 pA, P < 0.003), and exhibited higher frequency–current gain values (DNE = 0.087 ± 0.012 Hz/pA, control = 0.050 ± 0.004 Hz/pA, P < 0.02). Taken together, our data show previously unreported effects of DNE on XII MN function and may also help to explain the association between DNE and the incidence of central and obstructive apneas.
Superior Thyroid Cornu Anatomical Variation Causing Globus Pharyngeous and Dysphagia
Authors: Hajiioannou Jiannis K. , Florou Vasiliki , Kousoulis Panagiotis
Published: November 2010

Objective. Rare case presentation of thyroid cartilage variation causing globus sensation and dysphagia.Method. Case report and review of the literature concerning thyroid cartilage variant of clinical significance.Results. Middle-aged male patient presented with globus sensation and painful swallow without previous injury of the larynx. Clinical examination and diagnostic procedures revealed a rare anatomic aberrance of the thyroid cartilage. Surgical treatment was declined by the patient who accepted a yearly followup.Conclusion. Morphometric studies do not report the dislocation of the superior thyroid cornu, and very few cases have been described either of which were attributed to trauma or to unknown cause. The present case is to be added to the very few cases of superior thyroid cornu dislocation of unknown aetiology. Clinicians should be aware of this rare variation using CT neck as the imaging study of choice. Direct endoscopy rules out any synchronous disease or malignancies.
A Rare Devastating Complication of Lasik: Bilateral Fungal Keratitis
Authors: Taylan Sekeroglu H. , Erdem E. , Yar K. , Yağmur M. , Ersoz T. R. , Uguz A.
Published: November 2010

Purpose. To report an unusual case of severe bilateral fungal keratitis following laser in situ keratomileusis (LASIK).Method. A 48-year-old man developed bilateral diffuse corneal infiltration two weeks after LASIK. The corneal scrapings revealed fungal filaments but cultures were negative.Results. The corneal ulceration was improved on the left eye whereas spontaneous perforation occurred and finally evisceration was needed on the right eye despite topical and systemic antifungal treatment.Conclusions. Fungal keratitis, especially with bilateral involvement, is a very rare and serious complication of LASIK surgery. Clinical suspicion is crucial because most of fungal keratitis are misdiagnosed as bacterial keratitis and can lead serious visual results, even eye loss.