Asymmetry in Class II subdivision malocclusion: Assessment based on 3D surface models.

INTRODUCTION: There is currently no consensus in the literature whether the aetiology of a Class II subdivision is dental, skeletal or both. The aim of this study was to identify and quantify skeletal and dental asymmetries in Class II subdivision malocclusions. METHODS: CBCTs from 33 Class II subdivision malocclusion patients were used to construct 3D volumetric label maps. Eighteen landmarks were identified. The original scan and associated 3D volumetric label map were mirrored. Registration of the original and mirrored images relative to the anterior cranial base, maxilla and mandible were performed. Surface models were generated, and 3D differences were quantified. Statistical analysis was performed. RESULTS: Anterior cranial base registration showed significant differences for fossa vertical difference, fossa roll, mandibular yaw, mandibular lateral displacement and lower midline displacement. Regional registrations showed significant differences for antero-posterior (A-P) mandibular length, maxillary roll, A-P maxillary first molar position, maxillary first molar yaw and maxillary first molar roll. Class II subdivision patients also show an asymmetric mandibular length as well as an asymmetric gonial angle. Moderate correlations were found between the A-P molar relationship and fossa A-P difference, mandibular first molar A-P difference, maxillary first molar A-P difference and maxillary first molar yaw. CONCLUSIONS: This study suggests that Class II subdivisions can result from both significant skeletal and dental factors. Skeletal factors include a shorter mandible as well as posterior and higher displacement of the fossa on the Class II side, resulting in mandibular yaw. Dental factors include maxillary and mandibular first molar antero-posterior asymmetry.

Clogmia albipunctata (Williston, 1893) midgut physiology: pH control and functional relationship with Lower Diptera (nematoceran) especially with hematophagous species.

Clogmia albipunctata (Williston, 1893) is a non-hematophagous insect belonging to the order Diptera, suborder Nematocera (Lower Diptera) and family Psychodidae. In the present work, we investigated how C. albipunctata control their midgut pH under different physiological conditions, comparing their midgut physiology with some nematoceran hematophagous species. The C. albipunctata midgut pH was measured after ingestion of sugar, protein and under the effect of the alkalinizing hormone released in the hemolymph of the hematophagous sand fly Lutzomyia longipalpis obtained just after a blood meal. The midgut pH of unfed or sugar-fed C. albipunctata is 5.5-6, and its midgut underwent alkalinization after protein ingestion or under treatment with hemolymph collected from blood fed L. longipalpis. These results suggested that in nematocerans, mechanisms for pH control seem shared between hematophagous and non-hematophagous species. This kind of pH control is convenient for successful blood digestion. The independent evolution of many hematophagous groups from the Lower Diptera suggests that characteristics involved in midgut pH control were already present in non-hematophagous species and represent a readiness for adaptation to this feeding mode.

Na+/K+-ATPase Activation by cAMP in the Midgut of Lutzomyia longipalpis (Lutz & Neiva, 1912; Diptera: Psychodidae).

Lutzomyia longipalpis (Lutz & Neiva, 1912) females have been intensively studied regarding the regulation of midgut pH. The mechanisms involved in pH regulation are complex, and some aspects remain to be clarified. Here, we investigated the role of the Na+/K+-ATPase pump as an electrochemical potential generator and its modulation by the second messenger cAMP in the midgut of female L. longipalpis. Our results suggest that not only may Na+/K+-ATPase be the main generator of an electrochemical potential across membranes in the midgut of female L. longipalpis, but also its activity is positively regulated by cAMP. cAMP-mediated Na+/K+-ATPase pump activity might be necessary to maintain the transport of the nutrients produced during blood digestion.

First report of Y-linked genes in the kissing bug Rhodnius prolixus.

BACKGROUND: Due to an abundance of repetitive DNA, the annotation of heterochromatic regions of the genome such as the Y chromosome is problematic. The Y chromosome is involved in key biological functions such as male-fertility and sex-determination and hence, accurate identification of its sequences is vital. The hemipteran insect Rhodnius prolixus is an important vector of Chagas disease, a trypanosomiasis affecting 6-7 million people worldwide. Here we report the identification of the first Y-linked genes of this species. RESULTS: The R. prolixus genome was recently sequenced using separate libraries for each sex and the sequences assembled only with male reads are candidates for Y linkage. We found 766 such candidates and PCR tests with the ten largest ones, confirmed Y-linkage for all of them, suggesting that "separate libraries" is a reliable method for the identification of Y-linked sequences. BLAST analyses of the 766 candidate scaffolds revealed that 568 scaffolds contained genes or part of putative genes. We tested Y-linkage for 36 candidates and found that nine of them are Y-linked (the PCR results for the other 25 genes were inconclusive or revealed autosomal/X-linkage). Hence, we describe in this study, for the first time, Y-linked genes in the R. prolixus genome: two zinc finger proteins (Znf-Y1 and Znf-Y2), one metalloproteinase (Met-Y), one aconitase/iron regulatory protein (Aco-Y) and five genes devoid of matches in any database (Rpr-Y1 to Rpr-Y5). Expression profile studies revealed that eight genes are expressed mainly in adult testis (some of which presented a weak expression in the initial developmental stages), while Aco-Y has a gut-restricted expression. CONCLUSIONS: In this study we showed that the approach used for the R. prolixus genome project (separate sequencing of male and female DNA) is key to easy and fast identification of sex-specific (e.g. Y chromosome sequences). The nine new R. prolixus Y-linked genes reported here provide unique markers for population and phylogenetic analysis and further functional studies of these genes may answer some questions about sex determination, male fertility and Y chromosome evolution in this important species.

Positive and purifying selection on the Drosophila Y chromosome.

Y chromosomes, with their reduced effective population size, lack of recombination, and male-limited transmission, present a unique collection of constraints for the operation of natural selection. Male-limited transmission may greatly increase the efficacy of selection for male-beneficial mutations, but the reduced effective size also inflates the role of random genetic drift. Together, these defining features of the Y chromosome are expected to influence rates and patterns of molecular evolution on the Y as compared with X-linked or autosomal loci. Here, we use sequence data from 11 genes in 9 Drosophila species to gain insight into the efficacy of natural selection on the Drosophila Y relative to the rest of the genome. Drosophila is an ideal system for assessing the consequences of Y-linkage for molecular evolution in part because the gene content of Drosophila Y chromosomes is highly dynamic, with orthologous genes being Y-linked in some species whereas autosomal in others. Our results confirm the expectation that the efficacy of natural selection at weakly selected sites is reduced on the Y chromosome. In contrast, purifying selection on the Y chromosome for strongly deleterious mutations does not appear to be compromised. Finally, we find evidence of recurrent positive selection for 4 of the 11 genes studied here. Our results thus highlight the variable nature of the mode and impact of natural selection on the Drosophila Y chromosome.

Facilitating Direct Bonding for Lingual Retainers.

Directly bonded lingual retainers are not always easy because the available techniques do not keep the wire totally stable in position and there is risk of moist contamination. Indirect methods help to keep a moist-free environment and reduce chair time but have other drawbacks, such as lack of control over the composite placement leading to adhesive-tooth failure or undesirable flow of adhesive to gingival embrasures. The purpose of this report is to show a direct bonding method, helped by a laboratory made acrylic guide, which has benefits of direct and indirect techniques.

Silencing of maternal heme-binding protein causes embryonic mitochondrial dysfunction and impairs embryogenesis in the blood sucking insect Rhodnius prolixus.

The heme molecule is the prosthetic group of many hemeproteins involved in essential physiological processes, such as electron transfer, transport of gases, signal transduction, and gene expression modulation. However, heme is a pro-oxidant molecule capable of propagating reactions leading to the generation of reactive oxygen species. The blood-feeding insect Rhodnius prolixus releases enormous amounts of heme during host blood digestion in the midgut lumen when it is exposed to a physiological oxidative challenge. Additionally, this organism produces a hemolymphatic heme-binding protein (RHBP) that transports heme to pericardial cells for detoxification and to growing oocytes for yolk granules and as a source of heme for embryo development. Here, we show that silencing of RHBP expression in female fat bodies reduced total RHBP circulating in the hemolymph, promoting oxidative damage to hemolymphatic proteins. Moreover, RHBP knockdown did not cause reduction in oviposition but led to the production of heme-depleted eggs (white eggs). A lack of RHBP did not alter oocyte fecundation. However, produced white eggs were nonviable. Embryo development cellularization and vitellin yolk protein degradation, processes that normally occur in early stages of embryogenesis, were compromised in white eggs. Total cytochrome c content, cytochrome c oxidase activity, citrate synthase activity, and oxygen consumption, parameters that indicate mitochondrial function, were significantly reduced in white eggs compared with normal dark red eggs. Our results showed that reduction of heme transport from females to growing oocytes by RHBP leads to embryonic mitochondrial dysfunction and impaired embryogenesis.

Low conservation of gene content in the Drosophila Y chromosome.

Chromosomal organization is sufficiently evolutionarily stable that large syntenic blocks of genes can be recognized even between species as distantly related as mammals and puffer fish (450 million years (Myr) of divergence). In Diptera, the gene content of the X chromosome and the autosomes is well conserved: in Drosophila more than 95% of the genes have remained on the same chromosome arm in the 12 sequenced species (63 Myr of divergence, traversing 400 Myr of evolution), and the same linkage groups are clearly recognizable in mosquito genomes (260 Myr of divergence). Here we investigate the conservation of Y-linked gene content among the 12 sequenced Drosophila species. We found that only a quarter of the Drosophila melanogaster Y-linked genes (3 out of 12) are Y-linked in all sequenced species, and that most of them (7 out of 12) were acquired less than 63 Myr ago. Hence, whereas the organization of other Drosophila chromosomes traces back to the common ancestor with mosquitoes, the gene content of the D. melanogaster Y chromosome is much younger. Gene losses are known to have an important role in the evolution of Y chromosomes, and we indeed found two such cases. However, the rate of gene gain in the Drosophila Y chromosomes investigated is 10.9 times higher than the rate of gene loss (95% confidence interval: 2.3-52.5), indicating a clear tendency of the Y chromosomes to increase in gene content. In contrast with the mammalian Y chromosome, gene gains have a prominent role in the evolution of the Drosophila Y chromosome.

Prediction of 3-dimensional pharyngeal airway changes after orthognathic surgery: a preliminary study.

INTRODUCTION: Recent studies have shown some contradictory results when evaluating the consequences of orthodontic-surgical treatments on the pharyngeal airway. Therefore, the purpose of this study was to correlate the amount of jaw displacement with the volume variation and the minimal cross-sectional area of the pharyngeal airway. A comparison was made between the correlations with the percentage and the absolute values of the measurement variations. METHODS: Forty-two patients were divided into 2 groups according to the kind of orthognathic surgery that they had undergone. Group 1 had 22 subjects who had undergone maxillary advancement associated with mandibular setback, and group 2 had 20 patients who had undergone maxillomandibular advancement. The pharyngeal airway was divided into the upper segment and the lower segment, and the sum of these volumetric measures resulted in the total volume. The maxillary and mandibular displacements were assessed using closest point iteration after a voxel-wise cone-beam computed tomography superimposition. Hence, jaw displacements were correlated, using Pearson's correlation and linear regression analysis, to the volume variations of the pharyngeal airway (first time separately and then both groups together) and to the minimal cross-sectional area variation. RESULTS: The strongest correlation found was between maxillary displacement and the upper segment in group 2 (r = 0.898, R(2) = 0.888; P ≤0.001). With the groups' data combined, the variables mandibular displacement and the lower segment showed a linear correlation (r = 0.921, R(2) = 0.914; P ≤0.001). Maxillary displacement showed a strong positive correlation with the minimal cross-sectional area variation in group 2 (r = 0.710, R(2) = 0.604; P ≤0.01). CONCLUSIONS: Correlations with the percentage values were substantially stronger than the correlations with the absolute values. Stronger positive correlations were found between the jaw's displacement and the volume variation of the volume segment that was closer to it in both kinds of surgeries. Only the maxillary displacement is a reliable predictor of the minimal cross-sectional area variation after maxillomandibular advancement.

Can cone-beam computed tomography superimposition help orthodontists better understand relapse in surgical patients?

This case report describes the interdisciplinary treatment of a 19-year-old Brazilian man with a Class I malocclusion, a hyperdivergent profile, an anterior open bite, and signs of temporomandibular joint internal derangement. The treatment plan included evaluation with a temporomandibular joint specialist and a rheumatologist, orthodontic appliances, and maxillomandibular surgical advancement with counterclockwise rotation. Cone-beam computed tomography images were taken before and after surgery at different times and superimposed at the cranial base to assess the changes after orthognathic surgery and to monitor quantitatively the internal derangement of the temporomandibular joints and surgical relapse. Our protocol can improve the orthodontist's understanding of surgical instability, demonstrate the clinical value of cone-beam computed tomography analysis beyond the multiplanar reconstruction, and guide patient management for the best outcome possible.

Inhibition of vertebrate complement system by hematophagous arthropods: inhibitory molecules, mechanisms, physiological roles, and applications.

In arthropods, hematophagy has arisen several times throughout evolution. This specialized feeding behavior offered a highly nutritious diet obtained during blood feeds. On the other hand, blood-sucking arthropods must overcome problems brought on by blood intake and digestion. Host blood complement acts on the bite site and is still active after ingestion, so complement activation is a potential threat to the host's skin feeding environment and to the arthropod gut enterocytes. During evolution, blood-sucking arthropods have selected, either in their saliva or gut, anticomplement molecules that inactivate host blood complement. This review presents an overview of the complement system and discusses the arthropod's salivary and gut anticomplement molecules studied to date, exploring their mechanism of action and other aspects related to the arthropod-host-pathogen interface. The possible therapeutic applications of arthropod's anticomplement molecules are also discussed.

Gut membrane proteins as candidate antigens for immunization of mice against the tick Amblyomma sculptum.

Amblyomma sculptum is widely distributed in Brazil and is the main vector of Rickettsia rickettsii, the causative agent of the Brazilian spotted fever (BSF). Tick gut proteins play an essential role in blood feeding, digestion, and protection of gut epithelium. Therefore, many of these were investigated as potential vaccine targets for tick-control strategies. The present study aimed to select transcripts corresponding to putative immunogenic proteins in the A. sculptum gut epithelial membrane, produce recombinant proteins and evaluate them as antigens against A. sculptum infestations. Three gut proteins - AsMucin, AsAPP, and AsLAMP - and a chimeric protein (rAsChimera) based on 22 peptides containing putative B cell epitopes from seven different gut proteins were evaluated as anti-A. sculptum antigens. Mice immunizations revealed that all recombinant targets elicited humoral response with significantly increased IgG levels compared to controls. For rAsChimera, IgG levels remained significantly higher than controls up to 75 days after the end of the immunization. Challenge trials revealed that vaccination with the chimeric protein was the most effective against A. sculptum, inducing 100 % nymph mortality and reaching 80.8 % efficacy against females. The other three proteins did not induce relevant protection, as AsAPP had only 26.6 % efficacy, whereas AsMucin and AsLAMP induced no protection. These data indicate that targeting gut protein immunogenic regions may be an effective strategy for a vaccine formulation againstA. sculptum.

Evasion of the complement system by Leishmania through the uptake of C4bBP, a complement regulatory protein, and probably by the action of GP63 on C4b molecules deposited on parasite surface.

The complement system is a primary component of the vertebrate innate immune system, and its activity is harmful to microorganisms and parasites. To evade complement attack, some pathogens, such as viruses, bacteria, and protozoa, can interact with complement regulatory proteins from their hosts. Our research group has described the ability of Leishmania species to bind Factor H from human serum and use it as a tool to evade the complement system. However, there is no description of the interaction of Leishmania with other complement regulatory proteins, such as the C4b-binding protein (C4bBP), a negative regulator of classical and lectins complement system pathways. The results presented in this manuscript suggest that Leishmania infantum, L. amazonensis, and L. braziliensis recruit C4bBP from human serum. The uptake of C4bBP by L. infantum was studied in detail to improve our understanding of this inhibitory mechanism. When exposed to this complement regulator, parasites with inactivated GP63 bind to C4bBP and inactivate C4b deposited on their surface after serum exposure. This inactivation occurs by the action of Factor I, a complement system protease. In addition to the C4bBP-Factor I inactivation mechanism, the surface parasite protease GP63 can also inactivate soluble C4b molecules and probably that C4b molecules deposited on the parasites surface. This manuscript shows that Leishmania has two independent strategies to inactivate C4b molecules, preventing the progress of classical and lectins pathways. The identification of the C4bBP receptor on the Leishmania membrane may provide a new vaccine target to fight leishmaniasis.

Unravelling the genome of the brackish water malaria vector Anopheles aquasalis.

Malaria is a severe public health problem in several developing tropical and subtropical countries. Anopheles aquasalis is the primary coastal malaria vector in Central and South America and the Caribbean Islands, and it has the peculiar feature of living in water with large changes in salinity. Recent research has recognised An. aquasalis as an important model for studying the interactions of murine and human Plasmodium parasites. This study presents the complete genome of An. aquasalis and offers insights into its evolution and physiology. The genome is similar in size and gene content to other Neotropical anophelines, with 162 Mb and 12,446 protein-coding genes. There are 1387 single-copy orthologs at the Diptera level (eg. An. gambiae, An. darlingi and Drosophila melanogaster). An. aquasalis diverged from An. darlingi, the primary malaria vector in inland South America, nearly 20 million years ago. Proteins related to ion transport and metabolism belong to the most abundant gene families with 660 genes. We identified gene families relevant to osmosis control (e.g., aquaporins, vacuolar-ATPases, Na+/K+-ATPases, and carbonic anhydrases). Evolutionary analysis suggests that all osmotic regulation genes are under strong purifying selection. We also observed low copy number variation in insecticide resistance and immunity-related genes for all known classical pathways. The data provided by this study offers candidate genes for further studies of parasite-vector interactions and for studies on how anophelines of brackish water deal with the high fluctuation in water salinity. We also established data and insights supporting An. aquasalis as an emerging Neotropical malaria vector model for genetic and molecular studies.

Evolution and assembly of Anopheles aquasalis's immune genes: primary malaria vector of coastal Central and South America and the Caribbean Islands.

Anophelines are vectors of malaria, the deadliest disease worldwide transmitted by mosquitoes. The availability of genomic data from various Anopheles species allowed evolutionary comparisons of the immune response genes in search of alternative vector control of the malarial parasites. Now, with the Anopheles aquasalis genome, it was possible to obtain more information about the evolution of the immune response genes. Anopheles aquasalis has 278 immune genes in 24 families or groups. Comparatively, the American anophelines possess fewer genes than Anopheles gambiae s. s., the most dangerous African vector. The most remarkable differences were found in the pathogen recognition and modulation families like FREPs, CLIP and C-type lectins. Even so, genes related to the modulation of the expression of effectors in response to pathogens and gene families that control the production of reactive oxygen species were more conserved. Overall, the results show a variable pattern of evolution in the immune response genes in the anopheline species. Environmental factors, such as exposure to different pathogens and differences in the microbiota composition, could shape the expression of this group of genes. The results presented here will contribute to a better knowledge of the Neotropical vector and open opportunities for malaria control in the endemic-affected areas of the New World.

Origin and evolution of Y chromosomes: Drosophila tales.

Classically, Y chromosomes are thought to originate from X chromosomes through a process of degeneration and gene loss. Now, the availability of 12 Drosophila genomes provides an opportunity to study the origin and evolution of Y chromosomes in an informative phylogenetic context. Surprisingly, the majority of Drosophila Y-linked genes are recent acquisitions from autosomes and Y chromosome gene gains are more frequent than gene losses. Moreover, the Drosophila pseudoobscura Y chromosome lacks homology with the Y of most Drosophila species. Thus, the Drosophila Y has a different evolutionary history from canonical Y chromosomes (such as the mammalian Y) and it also might have a different origin.

Recent Technological Advances and Strategies for Arbovirus Vector Control.

In recent decades, we have seen the emergence and re-emergence of many arthropod-transmitted viruses (arboviruses) that pose important public health challenges worldwide [...].

Prevalence of malocclusion in public school students in the mixed dentition phase and its association with early loss of deciduous teeth.

OBJECTIVE: To determine the prevalence of malocclusion and its association with the early loss of deciduous teeth and other factors in children in the mixed dentition phase, aged six to eight years, enrolled in public schools in southern Brazil. METHODS: A cross-sectional study was conducted with a representative sample of 528 children from municipal public schools in 2009. Data collection involved a clinical examination for the determination of early tooth loss, dental caries, tongue pressure and malocclusion (outcome), as well as the administration of a questionnaire. Poisson regression analysis with robust variance was used to model the association between malocclusion and the independent variables. RESULTS: The prevalence of malocclusion and early tooth loss was 69.1% and 21.8%, respectively. In the raw data analysis, malocclusion was associated with age, early tooth loss, dental caries and tongue pressure. After the adjustment, the likelihood of malocclusion was greater among children older than eight years, those who exerted tongue pressure on the teeth and those with early tooth loss. The likelihood of malocclusion was 24% greater among children with early tooth loss, compared to those without tooth loss. CONCLUSION: The early loss of deciduous teeth was associated with the occurrence of malocclusion in the children studied.

An updated catalog of lipocalins of the chagas disease vector Rhodnius prolixus (Hemiptera, Reduviidae).

The haematophagy process by arthropods has been one of the main targets of studies in the parasite-host interaction, and the kissing-bug Rhodnius prolixus, vector of the protozoan Trypanosoma cruzi, has been one of the main models for such studies. Still in the 1980s, it was identified that among the salivary proteins for disrupting vertebrate host homeostasis, lipocalins were among the most relevant proteins for this process. Since then, 30 lipocalins have been identified in the salivary glands of R. prolixus, that promotes vasodilatation, prevents inflammation, act as anticoagulants and inhibits platelet aggregation. The present work aims to identify new lipocalins from R. prolixus, combining transcriptome and genome data. Identified new genes were mapped and had their structure annotated. To infer an evolutionary relationship between lipocalins, and to support the predicted functions for each lipocalin, all amino acid sequences were used to construct phylogenetic trees. We identified a total of 29 new lipocalins, 3 new bioaminogenic-biding proteins (which act to inhibit platelet aggregation and vasodilation), 9 new inhibitors of platelet aggregation, 7 new apolipoproteins and 10 lipocalins with no putative function. In addition, we observed that several of the lipocalins are also expressed in different R. prolxius tissues, including gut, central nervous system, antennae, and reproductive organs. In addition to newly identified lipocalins and a mapping the new and old lipocalins in the genome of R. prolixus, our study also carried out a review on functional status and nomenclature of some of the already identified lipocalins. Our study reinforces that we are far from understanding the role of lipocalins in the physiology of R. prolixus, and that studies of this family are still of great relevance.