bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aldehyde oxidase is coamplified with the World's most common Culex mosquito insecticide resistance‐associated esterases
Authors: Hemingway J. , Coleman M. , Paton M. , McCarroll L. , Vaughan A. , DeSilva D. 
Published: March 2003

AbstractThe evolution and spread of insecticide resistance is an important factor in human disease prevention and crop protection. The mosquito Culex quinquefasciatus is the main vector of the disease filariasis and a member of a species complex which is a common biting nuisance worldwide. The common insecticide resistance mechanism in this species involves germline amplification of the esterases estα21 and estβ21. This amplification has arisen once and rapidly spread worldwide. Less common and more variable resistance phenotypes involve coamplification of estα3 and estβ1, or individual amplification of a single estβ1, different alleles of the same estα and estβ gene loci. Estα21 and estβ21 are on the same large fragment of amplified DNA (amplicon) 2.7 kb apart. We have now shown that this amplicon contains another full‐length gene immediately 5′ of estα21 which codes for a molybdenum‐containing hydroxylase, with highest homology to aldehyde oxidase (AO) from other organisms. The full‐length putative AO gene is not present on the estα3/estβ1 or estβ1 amplicons, but multiple truncated 5′ ends of this gene are present around the presumed estα3/estβ1 amplicon breakpoint. Polymerase chain reaction (PCR) analysis of insecticide‐susceptible genomic DNA demonstrated that a different allele of the putative AO gene in its non‐amplified form is immediately 5′ of estα. The ‘AO’ gene on the estα21/estβ21 amplicon is expressed and resistant insects have greater AO activity. This AO activity is sensitive to inhibition by an aldehyde‐containing herbicide and pesticide. This enzyme may confer a selective advantage to these insects in the presence of insecticide, as AO in mammals is believed to be important in the detoxification process of several environmental pollutants.
Development of a Sindbis virus expression system that efficiently expresses green fluorescent protein in midguts of Aedes aegypti following per os infection
Authors: Olson K. E. , Myles K. M. , Seabaugh R. C. , Higgs S. , Carlson J. O. , Beaty B. J. 
Published: March 2003

AbstractA double subgenomic Sindbis (dsSIN) virus, MRE/3′2 J/GFP, was constructed to efficiently express green fluorescent protein (GFP) in the midgut of Aedes aegypti following per os infection. The MRE/3′2 J/GFP RNA genome contained the nonstructural genes and cis‐acting sequences of the dsSIN virus, TE/3′2 J/GFP, but had the structural genes of MRE16 SIN virus. MRE/3′2 J/GFP virus, unlike TE/3′2 J/GFP virus, efficiently infected mosquitoes orally. At 1–2 days postinfection, GFP was observed as multiple foci of expression on the lumenal side of the midgut. At 10–12 days postinfection, thirteen of fifteen mosquitoes infected with MRE/3′2 J/GFP virus had high levels of GFP expression in the mosquito midgut. The MRE3′2 J dsSIN expression system should be an important tool for efficient gene expression in Ae. aegypti midguts.
Molecular characterization of a prophenoloxidase cDNA from the malaria mosquitoAnopheles stephensi
Authors: Cui L. , Luckhart S. , Rosenberg R. 
Published: March 2003

AbstractSome refractory anopheline mosquitoes are capable of killingPlasmodium, the causative agent of malaria, by melanotic encapsulation of invading ookinetes. Phenoloxidase (PO) appears to be involved in the formation of melanin and toxic metabolites in the surrounding capsule. A cDNA encodingAnopheles stephensiprophenoloxidase (Ans‐proPO) was isolated from a cDNA library screened with an amplimer produced by reverse transcriptase polymerase chain reaction (RT‐PCR) with degenerate primers designed against conserved proPO sequences. The 2.4‐kb‐long cDNA has a 2058 bp open reading frame encoding Ans‐proPO of 686 amino acids. The deduced amino acid sequence shows significant homology to other insect proPO sequences especially at the two putative copper‐binding domains. InA. stephensi, Ans‐proPO expression was detected in larval, pupal and adult stages. The Ans‐proPO mRNA was detected by RT‐PCR andin situhybridization in haemocytes, fat body and epidermis of adult female mosquitoes. A low level of expression was detected in the ovaries, whereas no expression was detected in the midguts. Semi‐quantitative RT‐PCR analysis of Ans‐proPO mRNA showed that its expression was similar in adult female heads, thoraxes and abdomens. No change in the level of Ans‐proPO expression was found in adult females after blood feeding, bacterial challenge orPlasmodium bergheiinfection. However, elevated PO activity was detected inP. berghei‐infected mosquitoes, suggesting that in non‐selected permissive mosquitoes PO may be involved in limiting parasite infection. Genomic Southern blot and immunoblots suggest the presence of more than one proPO gene in theA. stephensigenome, which is consistent with the findings in other Diptera and Lepidoptera species. The greatest similarity in sequence and expression profile between Ans‐proPO andA. gambiaeproPO6 suggests that they might be homologues. Our results demonstrate that Ans‐proPO is constitutively expressed through different developmental stages and under different physiological conditions, implying that other factors in the proPO activation cascade regulate melanotic encapsulation.
Developing SCAR markers to study predation on Trialeurodes vaporariorum
Authors: Agustí N. , De Vicente M. C. , Gabarra R. 
Published: March 2003

AbstractDNA markers of Trialeurodes vaporariorum were developed to detect remains of these whitefly in the gut of the predator Dicyphus tamaninii. A 2400‐bp DNA fragment of T. vaporariorum, absent in other closely related prey species and in the predator banding pattern, was identified by random amplified polymorphic DNA (RAPD) analysis. After cloning and sequencing this fragment, two pairs of sequence‐characterized amplified region (SCAR) primers were developed, amplifying single bands of 2100 bp and 310 bp, respectively. Detection of T. vaporariorum DNA in the predator gut was only possible using the primers that amplified the shortest fragment. Specificity tests performed with this pair of primers showed the presence of the 310‐bp band for T. vaporariorum in all stages.
The highly compact structure of the mitochondrial DNA polymerase genomic region ofDrosophila melanogaster: functional and evolutionary implications
Authors: Lefai E. , Fernández‐Moreno M. A. , Kaguni L. S. , Garesse R. 
Published: March 2003

AbstractThe structure of aDrosophila melanogastergenomic region containing five tightly clustered genes has been determined and evaluated with regard to its functional and evolutionary relationships. In addition to the genes encoding the two subunits (α and β) of the DNA polymerase γ holoenzyme, the key enzyme for mitochondrial DNA replication, other genes contained in the cluster may be also involved in the cellular distribution of mitochondria and in the coordination of mitochondrial and nuclear DNA replication. The gene cluster is extremely compact, with very little intergenic space. It contains two bidirectional promoter regions, and particularly notable is the 5′ end overlap detected in two of its genes, an exceptional situation in both prokaryotic and eukaryotic genome organization.
Comparative linkage map development and identification of an autosomal locus for insensitive acetylcholinesterase‐mediated insecticide resistance in Culex tritaeniorhynchus
Authors: Mori A. , Tomita T. , Hidoh O. , Kono Y. , Severson D. W. 
Published: March 2003

AbstractA comparative linkage map for Culex tritaeniorhynchus was constructed based on restriction fragment length polymorphism markers using cDNAs from Aedes aegypti. Linear orders of marker loci in Cx. tritaeniorhynchus were identical to Culex pipiens wherein chromosomes 2 and 3 reflect whole‐arm rearrangements compared to A. aegypti. However, the sex determination locus in Cx. tritaeniorhynchus maps to chromosome 3, in contrast to Cx. pipiens and Ae. aegypti where it is located on chromosome 1. Our results indicate that insensitive acetylcholinesterase (AChE)‐mediated organophosphate resistance is controlled by a single major gene (AChER) on chromosome 2, while the AChE structural gene (Ace) is located on chromosome 1. No evidence for a second Ace gene was observed, even under very low stringency hybridization conditions.
Analysis of expressed sequence tags from subtracted and unsubtracted Ctenocephalides felis hindgut and Malpighian tubule cDNA libraries
Authors: Gaines P. J. , Brandt K. S. , Eisele A. M. , Wagner W. P. , Bozic C. M. , Wisnewski N. 
Published: March 2003

AbstractInsect hindgut and Malpighian tubule (HMT) tissues regulate the contents of the haemolymph through the excretion of waste products and the specific reabsorption of nutrients. As such, they perform a role that is essential for survival and may contain molecular targets for insect control strategies. In order to discover genes expressed in the HMT tissues of the cat flea, Ctenocephalides felis, expressed sequence tags (ESTs) were generated from an unsubtracted HMT cDNA library and from a subtracted HMT cDNA library that had been enriched for HMT‐specific cDNAs. A total of 4844 ESTs were analysed from both libraries: 3657 from the subtracted library and 1187 from the unsubtracted library. Of the 1418 distinct ESTs identified from both libraries, 953 had significant similarity to other sequences reported in the GenBank™ database. A comparison of the results from the two libraries confirmed that the percentages of genes likely to be involved with metabolism, cell structure, and digestion were reduced by the subtraction procedure, whereas genes likely to be involved with ion transport were enriched. Analysis of the prevalence of three individual cDNAs in each library revealed that the actin cDNA was reduced in the subtracted library whereas the cDNAs encoding allantoinase and a peritrophin‐like protein were greatly enriched in the subtracted library. Northern blot analysis demonstrated that the actin cDNA was expressed in both the HMT and carcass tissues, whereas the allantoinase and peritrophin‐like cDNAs were detected exclusively in the HMT tissues. In total, 97 distinct ESTs that appear to encode proteins involved with ion transport were analysed. Some of these proteins may be directly involved with diuresis or the specific reabsorption of salts and nutrients, and thus may be potential molecular targets for flea control strategies.
Hidden from the host: Spiroplasma bacteria infecting Drosophila do not cause an immune response, but are suppressed by ectopic immune activation
Authors: Hurst Gregory D. D. , Anbutsu Hisashi , Kutsukake Mayako , Fukatsu Takema 
Published: March 2003

AbstractInsects and other arthropods have an effective innate immune system that can clear infections with bacteria and other microorganisms. Despite this ability, one group of bacteria, the spiroplasmas, survive unharmed within the haemolymph of a wide range of arthropod hosts. We investigated the interaction between one member of this clade, a relative of Spiroplasma poulsonii, and the immune system of its Drosophila host. Expression of antimicrobial genes in spiroplasma‐infected flies did not differ from wild‐type controls either in the naturally infected state, nor after septic shock. We therefore concluded that spiroplasma infection did not induce an immune response in its host, but that this absence of response was unlikely to be because the bacterium inhibited response. Further experiments revealed immune reactions induced ectopically did reduce parasite titre. We therefore conclude that this bacterium has a novel form of interaction with its host, being hidden from the host immune system, but potentially suppressible by it.
Isolation and characterization of a termite transferrin gene up‐regulated on infection
Authors: Thompson Graham J. , Crozier Y. Ching , Crozier Ross H. 
Published: March 2003

AbstractPCR‐based subtractive hybridization was used to isolate genes preferentially expressed in a termite (Mastotermes darwiniensis) following exposure to an entomopathogenic fungus. The subtraction procedure yielded a cDNA clone encoding a putative transferrin that, when sequenced to its ends, is the largest (728 amino acids) for any insect transferrin characterized to date. Cysteines and residues comprising putative iron‐binding sites are conserved in both N‐ and C‐terminal lobes, suggesting structural and functional similarity to diferric vertebrate transferrins. A quantitative PCR assay confirmed a significant increase in transferrin expression following infection, suggesting its up‐regulation is part of the innate immune response. However, codon‐based tests for selection among known insect transferrins revealed only a small proportion of codon‐sites positively selected. Thus, unlike certain vertebrate transferrin lineages, no widespread evidence for pathogen‐mediated positive selection was detected at this locus.
Unusual case of bilateral talon cusp associated with dens invaginatus
Authors: De Sousa S. M. G. , Tavano S. M. R. , Bramante C. M. 
Published: March 2003

de Sousa SMG, Tavano SMR, Bramante CM. Unusual case of bilateral talon cusp associated with dens invaginatus (Clinical article). International Endodontic Journal, 32, 494–498 1999.Case report This paper presents a rare case of bilateral talon cusp in permanent maxillary central incisors, one on the labial and another on the lingual surface of each tooth. The condition was associated with dens invaginatus in a maxillary permanent lateralincisor, but no developmental syndrome was identified. The left central incisor required no treatment because the aesthetic appearance was satisfactory and neither occlusal interferences nor caries were present. After careful investigation of the right lateral incisor, a sealant was applied. Root canal treatment was indicated for the right central incisor that had a wide open apex with thin, weak, divergent walls, and an apical radiolucency.
Mechanisms of antimicrobial activity of calcium hydroxide: a critical review
Authors: Siqueira J. F. , Lopes H. P. 
Published: March 2003

Literature review The primary function of calcium hydroxide as a routine intracanal medicament is to provide antimicrobial activity. However, the mechanisms of antimicrobial activity of calcium hydroxide are not well known. Physicochemicalproperties of this substance may limit its effectiveness in disinfecting the entire root canal system. In addition, calcium hydroxide is not effective against all bacterial species found in root canal infections. Association with other medicaments may enhance the efficacy of the intracanal medication in eliminating residual bacteria in the root canal system.
Cyclic fatigue of ProFile rotary instruments after clinical use
Authors: Yared G. M. , Dagher F. E. Bou , Machtou P. 
Published: March 2003

Aim  The purpose of this study was to evaluate cyclic fatigue of .06 ProFile Ni‐Ti rotary instruments after clinical use in molar teeth.Methodology  In group 1, instruments size 40–15 were used in a crown‐down technique using 2.5% NaOCl as an irrigant. Fifty‐two molars were included and 13 sets of Profile Ni‐Ti rotary instruments were used. Each set of instruments was used in four molars, and was steam autoclaved before each use. Group 2 (10 sets of new ProFile Ni‐Ti rotary instruments) was the control group. Cyclic fatigue was tested by rotating the instruments in a 908 metallic tube until they broke.Results  One‐way analysis of variance did not show any statistically significant differences amongst the files from both groups regarding cyclic fatigue.Conclusions  It was concluded that sterilization and clinical use in the presence of NaOCl did not lead to a decrease in the number of rotations to breakage of the files.
The use of 3D computerized reconstruction for the study of coronal microleakage
Authors: Lyroudia K. , Pantelidou O. , Mikrogeorgis G. , Chatzikallinikidis C. , Nikopoulos N. , Pitas I. 
Published: March 2003

AbstractAimThe purpose of this study was to evaluate a new method for studying coronal microleakage associated with root‐filled teeth.MethodologyTwenty human mandibular posterior teeth were prepared chemomechanically with the stepback technique and then divided into two groups of 10 teeth each. The canals were filled using lateral condensation of gutta‐percha points; Roth’s 801 was used as a sealer for the first group, and Ketac‐Endo for the second. After 48 h, the temporary fillings in the access cavities were removed, the roots coated with three layers of nail polish and then the teeth were exposed to artificial saliva for 40 days. Subsequently, the crowns of the teeth were placed into Indian ink for 4 days before the coating was removed and the teeth embedded in a two‐phase polyester resin. Serial cross sections were taken from each specimen using a microtome, and each cross section photographed under a stereoscopic microscope. The photographs of the cross sections were digitized using an image scanner and the contours of the external surface of the teeth, the obturated root canals and the boundaries of dye penetration were followed. Finally, a three‐dimensional surface representation was achieved using the triangulation method.ResultsAlthough the sample size and the experimental methods were not designed to form valid groups, the results showed that all roots obturated with Ketac‐Endo sealer had dye microleakage, whilst only three teeth of the Roth’s 801 group had dye microleakage.ConclusionsThe 3D reconstruction of dye microleakage proved to be an interesting method and a useful tool for the evaluation of coronal microleakage when using different types of root canal sealers.
Shaping ability of Hero 642 rotary nickel–titanium instruments in simulated root canals: Part 1
Authors: Thompson S. A. , Dummer P. M. H. 
Published: March 2003

AbstractAimTo determine the general efficacy and shaping ability of Hero 642 nickel–titanium rotary instruments during the preparation of simulated canals. Part 1 of this two‐part report describes the efficacy of the instruments in terms of three‐dimensional canal form.MethodologyA total of 40 simulated root canals made up of four different shapes in terms of angle and position of curvature were prepared by Hero 642 instruments using a crown‐down preparation sequence. The efficacy of the instruments was assessed in terms of preparation time, instrument failure, canal blockages and loss of canal length. Intra‐canal impressions were taken of the prepared canals in order to assess three‐dimensional canal form.ResultsThe mean time for canal preparation was 8.6 min and was influenced significantly (P < 0.05) by canal shape. Two instruments fractured and eight instruments deformed; significant differences were observed between canal shapes (P < 0.05). All of the canals remained patent. Fifteen canals (39.5%) maintained the correct working distance, 15 lost distance and eight canals gained length. Examination of intracanal impressions demonstrated that the majority of canals (79%) had apical stops; canal shape had a significant influence (P < 0.001) on the quality of apical stops. With one exception all canals had smooth canal walls and all of the canals showed good flow characteristics. Taper was poor in 30 canals (79%) and good in eight canals (21%).ConclusionsHero 642 rotary nickel–titanium instruments prepared simulated canals rapidly but with a three‐dimensional form that lacked adequate taper.
A ‘one‐bottle’ adhesive system for bonding a fibre post into a root canal: an SEM evaluation of the post–resin interface
Authors: Ferrari M. , Mannocci F. 
Published: March 2003

Abstract Ferrari M, Mannocci F. A ‘one‐bottle’ adhesive system for bonding a fibre post into a root canal: an SEM evaluation of the post‐resin interface. International Endodontic Journal, 33, 397–400, 2000.AimThis report presents a case in which a ‘one‐bottle’ adhesive system was used in combination with proprietary resin cement for bonding a fibre post.MethodologyThe fibre post was placed into the root canal of a fractured root under clinical conditions and then extracted 1 week later. Using scanning electron microscopy, half of the root was evaluated for hybrid layer formation and the other half for assessing resin tags.ResultsThe investigation demonstrated that a ‘one‐bottle’ system can infiltrate etched dentine.ConclusionsThe ‘one‐bottle’ system tested in this study can create a mechanical interlocking with root etched dentine under clinical conditions.
Effects of four Ni–Ti preparation techniques on root canal geometry assessed by micro computed tomography
Authors: Peters O. A. , Schönenberger K. , Laib A. 
Published: March 2003

AbstractAim The aim of this study was to compare the effects of four preparation techniques on canal volume and surface area using three‐dimensionally reconstructed root canals in extracted human maxillary molars. In addition, µCT data was used to describe morphometric parameters related to the four preparation techniques.Methodology  A micro computed tomography scanner was used to analyse root canals in extracted maxillary molars. Specimens were scanned before and after canals were prepared using Ni–Ti – K‐Files, Lightspeed instruments, ProFile .04 and GT rotary instruments. Differences in dentine volume removed, canal straightening, the proportion of unchanged area and canal transportation were calculated using specially developed software.Results Instrumentation of canals increased volume and surface area. Prepared canals were significantly more rounded, had greater diameters and were straighter than unprepared canals. However, all instrumentation techniques left 35% or more of the canals’ surface area unchanged. Whilst there were significant differences between the three canal types investigated, very few differences were found with respect to instrument types.Conclusions Within the limitations of the µCT system, there were few differences between the four canal instrumentation techniques used. By contrast, a strong impact of variations of canal anatomy was demonstrated. Further studies with 3D‐techniques are required to fully understand the biomechanical aspects of root canal preparation.
Apical extrusion of debris and irrigants using two hand and three engine‐driven instrumentation techniques
Authors: Ferraz C. C. R. , Gomes N. V. , Gomes B. P. F. A. , Zaia A. A. , Teixeira F. B. , Souza‐Filho F. J. 
Published: March 2003

AbstractAimTo evaluate the weight of debris and irrigant volume extruded apically from extracted teeth in vitro after endodontic instrumentation using the balanced force technique, a hybrid hand instrumentation technique, and three engine‐driven techniques utilizing nickel–titanium instruments (ProFile .04, Quantec 2000 and Pow‐R).MethodologyFive groups of 20 extracted human teeth with single canals were instrumented using one or other of five techniques: balanced force, hybrid, Quantec 2000, ProFile .04, or Pow‐R. Debris extruded from the apical foramen during instrumentation were collected into preweighed 1.5 mL tubes. Following instrumentation, the volume of extruded irrigant fluid was determined by visual comparison to control centrifuge tubes filled with 0.25 mL increments of distilled water. The weight of dry extruded dentine debris was also established.ResultsOverall, the engine‐driven techniques extruded less debris than the manual ones. However, there was no statistical difference between the balanced force technique and the engine‐driven methods. The volume of irrigant extruded through the apex was directly associated with the weight of extruded debris, except within the ProFile group. The hybrid technique was associated with the greatest extrusion of both debris and irrigant.ConclusionsOverall, the engine‐driven nickel–titanium systems were associated with less apical extrusion.