An aphid symbiont confers protection against a specialized RNA virus, another increases vulnerability to the same pathogen.

Insects often harbour heritable symbionts that provide defence against specialized natural enemies, yet little is known about symbiont protection when hosts face simultaneous threats. In pea aphids (Acyrthosiphon pisum), the facultative endosymbiont Hamiltonella defensa confers protection against the parasitoid, Aphidius ervi, and Regiella insecticola protects against aphid-specific fungal pathogens, including Pandora neoaphidis. Here, we investigated whether these two common aphid symbionts protect against a specialized virus A.

Variation in adhesion of and in saliva-derived biofilms on raw materials of orthodontic brackets.

Objective: To evaluate differences in the adhesion levels of the most common oral pathogens, and , in human saliva-derived microcosm biofilms with respect to time and raw materials of orthodontic brackets.

Methods: The samples were classified into three groups of bracket materials: 1) monocrystalline alumina ceramic (CR), 2) stainless steel metal (SS), and 3) polycarbonate plastic (PL), and a hydroxyapatite (HA) group was used to mimic the enamel surface. Saliva was collected from a healthy donor, and saliva-derived biofilms were grown on each sample.

Urethane Dimethacrylate Influences the Cariogenic Properties of .

Concerns regarding unbound monomers in dental composites have increased with the increased usage of these materials. This study assessed the biological effects of urethane dimethacrylate (UDMA), a common monomer component of dental composite resins, on the cariogenic properties of . Changes in the growth rate, biofilm formation, interaction with saliva, surface hydrophobicity, adhesion, glucan synthesis, sugar transport, glycolytic profiles, and oxidative- and acid-stress tolerances of were evaluated after growing the cells in the presence and absence of UDMA.

Self-perpetuating ecological-evolutionary dynamics in an agricultural host-parasite system.

Ecological and evolutionary processes may become intertwined when they operate on similar time scales. Here we show ecological-evolutionary dynamics between parasitoids and aphids containing heritable symbionts that confer resistance against parasitism. In a large-scale field experiment, we manipulated the aphid's host plant to create ecological conditions that either favoured or disfavoured the parasitoid.

Effect of Bisphenol A Glycol Methacrylate on Virulent Properties of Streptococcus mutans UA159.

Bisphenol A glycidyl methacrylate (bis-GMA), which is released into the oral environment by dental composites through incomplete polymerization, hydrolysis, and mechanical degradation, can significantly influence oral ecology around resin-based materials. The purpose of this study was to investigate how bis-GMA changes the virulence properties of Streptococcus mutans, a major cariogenic bacterium in humans. The results show that bis-GMA not only inhibited the planktonic growth of cells in medium containing glucose, fructose, or mannose, but also reduced the viability of S.

Breakdown of a defensive symbiosis, but not endogenous defences, at elevated temperatures.

Environmental factors, including temperature, can have large effects on species interactions, including mutualisms and antagonisms. Most insect species are infected with heritable bacterial symbionts with many protecting their hosts from natural enemies. However, many symbionts or their products are thermally sensitive; hence, their effectiveness may vary across a range of temperatures.

Multi-modal defences in aphids offer redundant protection and increased costs likely impeding a protective mutualism.

The pea aphid, Acyrthosiphon pisum, maintains extreme variation in resistance to its most common parasitoid wasp enemy, Aphidius ervi, which is sourced from two known mechanisms: protective bacterial symbionts, most commonly Hamiltonella defensa, or endogenously encoded defences. We have recently found that individual aphids may employ each defence individually, occasionally both defences together, or neither. In field populations, Hamiltonella-infected aphids are found at low to moderate frequencies and while less is known about the frequency of resistant genotypes, they show up less often than susceptible genotypes in field collections.

Compositional differences in multi-species biofilms formed on various orthodontic adhesives.

Objectives: To investigate the aspects of multi-species biofilm formation on various orthodontic adhesives with different surface characteristics.

Methods: Multi-species biofilms using 13 bacterial species were grown on the surfaces of composite, compomer, and resin-modified glass-ionomer cement (RMGI). The changes in Streptococcus mutans (Sm), Streptococcus sobrinus (Ss), Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa), and total bacteria were determined at day 1 (T1) and day 4 (T2) using real-time polymerase chain reaction.

Antimicrobial and physical characteristics of orthodontic primers containing antimicrobial agents.

Objective: To compare the antimicrobial and physical properties of experimental primers containing chlorhexidine (CHX) or ursolic acid (UA) with a commercial primer.

Materials And Methods: Two antibacterial agents, 3 mg each of CHX and UA were incorporated respectively into 1 ml of Transbond XT primer (TX) to form antibacterial primers, TX-CHX and TX-UA. The antimicrobial activity of the three primers (TX, TX-CHX, and TX-UA) against Streptococcus mutans in both planktonic and biofilm phases was analyzed by determining minimum inhibitory and bactericidal concentrations and by performing growth and biofilm assays.

Adhesion of periodontal pathogens to self-ligating orthodontic brackets: An in-vivo prospective study.

Introduction: Our aims were to analyze adhesion of periodontopathogens to self-ligating brackets (Clarity-SL [CSL], Clippy-C [CC] and Damon Q [DQ]) and to identify the relationships between bacterial adhesion and oral hygiene indexes.

Methods: Central incisor brackets from the maxilla and mandible were collected from 60 patients at debonding after the plaque and gingival indexes were measured. Adhesions of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Fusobacterium nucleatum (Fn), and Tannerella forsythia (Tf) were quantitatively determined using real-time polymerase chain reactions.

Specificity of Multi-Modal Aphid Defenses against Two Rival Parasitoids.

Insects are often attacked by multiple natural enemies, imposing dynamic selective pressures for the development and maintenance of enemy-specific resistance. Pea aphids (Acyrthosiphon pisum) have emerged as models for the study of variation in resistance against natural enemies, including parasitoid wasps. Internal defenses against their most common parasitoid wasp, Aphidius ervi, are sourced through two known mechanisms- 1) endogenously encoded resistance or 2) infection with the heritable bacterial symbiont, Hamiltonella defensa.

Changes in salivary periodontal pathogens after orthodontic treatment: An in vivo prospective study.

Objective:   To analyze the initial changes in salivary levels of periodontal pathogens after orthodontic treatment with fixed appliances.

Materials And Methods:   The subjects consisted of 54 adult patients. The Simplified Oral Hygiene Index, Plaque Index, and Gingival Index were measured as periodontal parameters.

Uncovering symbiont-driven genetic diversity across North American pea aphids.

Heritable genetic variation is required for evolution, and while typically encoded within nuclear and organellar genomes, several groups of invertebrates harbour heritable microbes serving as additional sources of genetic variation. Hailing from the symbiont-rich insect order Hemiptera, pea aphids (Acyrthosiphon pisum) possess several heritable symbionts with roles in host plant utilization, thermotolerance and protection against natural enemies. As pea aphids vary in the numbers and types of harboured symbionts, these bacteria provide heritable and functionally important variation within field populations.

Total synthesis of diptoindonesin G via a highly efficient domino cyclodehydration/intramolecular Friedel-Crafts acylation/regioselective demethylation sequence.

A highly efficient total synthesis of diptoindonesin G is described employing a domino dehydrative cyclization/intramolecular Friedel-Crafts acylation/regioselective demethylation reaction of aryloxyketone 7 by the action of BCl(3) wherein the tetracyclic 6H-anthra[1,9-bc]furan-6-one skeleton was constructed via the 3-arylbenzofuran in a one-pot manner. This is the first example of the strategic combination of these three reactions in a cascade fashion. The routes presented here allow for direct access to diptoindonesin G and its analogues.

Substrate binding mechanism of a type I extradiol dioxygenase.

A meta-cleavage pathway for the aerobic degradation of aromatic hydrocarbons is catalyzed by extradiol dioxygenases via a two-step mechanism: catechol substrate binding and dioxygen incorporation. The binding of substrate triggers the release of water, thereby opening a coordination site for molecular oxygen. The crystal structures of AkbC, a type I extradiol dioxygenase, and the enzyme substrate (3-methylcatechol) complex revealed the substrate binding process of extradiol dioxygenase.

Expeditious synthesis of highly substituted indolizinones via a palladium-catalyzed domino sequence.

A direct one-pot approach to polysubstituted indolizinones from tertiary propargylic alcohols using a palladium-catalyzed domino process involving aminopalladation, reductive elimination, and 1,2-shift is described.

Diversity-oriented construction of highly substituted indolizinones.

Rapid generation of a small library of highly functionalized indolizonones was realized by exploiting three palladium-catalyzed cross-coupling reactions of 2-iodoindolizinones which in turn were readily accessed via sequential iodine-mediated cyclization/1,2-shift reactions of propargylic alcohols.

A direct approach to 5-hydroxybenzofurans via a platinum-catalyzed domino rearrangement/5-endo-dig cyclization reaction of quinols.

A highly efficient and atom-economical construction of 2-substituted 5-hydroxybenzofurans was accomplished by employing a platinum-catalyzed domino dienone-phenol rearrangement/5-endo-dig cyclization reaction of quinols bearing alkynes.

A neural network model with feature selection for Korean speech act classification.

A speech act is a linguistic action intended by a speaker. Speech act classification is an essential part of a dialogue understanding system because the speech act of an utterance is closely tied with the user's intention in the utterance. We propose a neural network model for Korean speech act classification.

Evolutionary genomics of inversions in Drosophila pseudoobscura: evidence for epistasis.

Drosophila pseudoobscura harbors a rich polymorphism for paracentric inversions on the third chromosome, and the clines in the inversion frequencies across the southwestern United States indicate that strong natural selection operates on them. Isogenic inversion strains were made from isofemale lines collected from four localities, and eight molecular markers were mapped on the third chromosome. Nucleotide diversity was measured for these loci and formed the basis of an evolutionary genomic analysis.