A noncoding melanophilin gene (MLPH) SNP at the splice donor of exon 1 represents a candidate causal mutation for coat color dilution in dogs

Coat color dilution in several breeds of dog is characterized by a specific pigmentation phenotype and sometimes accompanied by hair loss and recurrent skin inflammation, the so-called color dilution alopecia or black hair follicular dysplasia. Coat color dilution (d) is inherited as a Mendelian autosomal recessive trait. In a previous study, MLPH polymorphisms showed perfect cosegregation with the dilute phenotype within breeds. However, different dilute haplotypes were found in different breeds, and no single polymorphism was identified in the coding sequence that was likely to be causative for the dilute phenotype. We resequenced the 5'-region of the canine MLPH gene and identified a strong candidate single nucleotide polymorphism within the nontranslated exon 1, which showed perfect association to the dilute phenotype in 65 dilute dogs from 7 different breeds. The A/G polymorphism is located at the last nucleotide of exon 1 and the mutant A-allele is predicted to reduce splicing efficiency 8-fold. An MLPH mRNA expression study using quantitative reverse transcriptase-polymerase chain reaction confirmed that dd animals had only about approximately 25% of the MLPH transcript compared with DD animals. These results provide preliminary evidence that the reported regulatory MLPH mutation might represent a causal mutation for coat color dilution in dogs.

Behavioral dominance between female color morphs of a Lake Victoria cichlid fish

Species that exhibit genetic color polymorphism are suitable for studying the evolutionary forces that maintain heritable phenotypic variation in nature. Male color morphs often differ in behavioral dominance, affecting the evolution of color polymorphisms. However, behavioral dominance among female color morphs has received far less attention. We studied a polymorphic population of the cichlid fish Neochromis omnicaeruleus from Lake Victoria, in which 3 distinct female color morphs coexist, black-and-white blotched (WB), orange blotched (OB), and plain (P) color morphs. First, we investigated dominance relationships among female morphs using triadic and dyadic encounters in the laboratory. In triadic encounters, both WB and OB females dominated plain, whereas WB females dominated OB females. Dominance of WB over OB was confirmed using dyadic encounters. In a second experiment, blotched (WB or OB) and plain full-sib sisters were bred by crossing a blotched and a plain parent. In dyadic encounters, WB female morphs dominated their plain sisters, suggesting that dominance of WB females is a pleiotropic effect of color or that genes coding for color and those influencing behavioral dominance are genetically linked, explaining the association between color and behavioral dominance despite gene flow. We conclude that behavioral dominance asymmetries exist among female color morphs of the fish N. omnicaeruleus, and discuss possible mechanisms that may account for the tight association between color and behavioral dominance.

Polymorphisms within the canine MLPH gene are associated with dilute coat color in dogs

BACKGROUND Pinschers and other dogs with coat color dilution show a characteristic pigmentation phenotype. The fur colors are a lighter shade, e.g. silvery grey (blue) instead of black and a sandy color (Isabella fawn) instead of red or brown. In some dogs the coat color dilution is sometimes accompanied by hair loss and recurrent skin inflammation, the so called color dilution alopecia (CDA) or black hair follicular dysplasia (BHFD). In humans and mice a comparable pigmentation phenotype without any documented hair loss is caused by mutations within the melanophilin gene (MLPH). RESULTS We sequenced the canine MLPH gene and performed a mutation analysis of the MLPH exons in 6 Doberman Pinschers and 5 German Pinschers. A total of 48 sequence variations was identified within and between the breeds. Three families of dogs showed co-segregation for at least one polymorphism in an MLPH exon and the dilute phenotype. No single polymorphism was identified in the coding sequences or at splice sites that is likely to be causative for the dilute phenotype of all dogs examined. In 18 German Pinschers a mutation in exon 7 (R199H) was consistently associated with the dilute phenotype. However, as this mutation was present in homozygous state in four dogs of other breeds with wildtype pigmentation, it seems unlikely that this mutation is truly causative for coat color dilution. In Doberman Pinschers as well as in Large Munsterlanders with BHFD, a set of single nucleotide polymorphisms (SNPs) around exon 2 was identified that show a highly significant association to the dilute phenotype. CONCLUSION This study provides evidence that coat color dilution is caused by one or more mutations within or near the MLPH gene in several dog breeds. The data on polymorphisms that are strongly associated with the dilute phenotype will allow the genetic testing of Pinschers to facilitate the breeding of dogs with defined coat colors and to select against Large Munsterlanders carrying BHFD.

Visual constraints in foraging bumblebees: Flower size and color affect search time and flight behavior

In optimal foraging theory, search time is a key variable defining the value of a prey type. But the sensory-perceptual processes that constrain the search for food have rarely been considered. Here we evaluate the flight behavior of bumblebees (Bombus terrestris) searching for artificial flowers of various sizes and colors. When flowers were large, search times correlated well with the color contrast of the targets with their green foliage-type background, as predicted by a model of color opponent coding using inputs from the bees' UV, blue, and green receptors. Targets that made poor color contrast with their backdrop, such as white, UV-reflecting ones, or red flowers, took longest to detect, even though brightness contrast with the background was pronounced. When searching for small targets, bees changed their strategy in several ways. They flew significantly slower and closer to the ground, so increasing the minimum detectable area subtended by an object on the ground. In addition, they used a different neuronal channel for flower detection. Instead of color contrast, they used only the green receptor signal for detection. We relate these findings to temporal and spatial limitations of different neuronal channels involved in stimulus detection and recognition. Thus, foraging speed may not be limited only by factors such as prey density, flight energetics, and scramble competition. Our results show that understanding the behavioral ecology of foraging can substantially gain from knowledge about mechanisms of visual information processing.

Null mutation of endothelin receptor type B gene in spotting lethal rats causes aganglionic megacolon and white coat color.

Mutations in the gene encoding the endothelin receptor type B (EDNRB) produce congenital aganglionic megacolon and pigment abnormalities in mice and humans. Here we report a naturally occurring null mutation of the EDNRB gene in spotting lethal (sl) rats, which exhibit aganglionic megacolon associated with white coat color. We found a 301-bp deletion spanning the exon 1-intron 1 junction of the EDNRB gene in sl rats. A restriction fragment length polymorphism caused by this deletion perfectly cosegregates with the sl phenotype. The deletion leads to production of an aberrantly spliced EDNRB mRNA that lacks the coding sequence for the first and second putative transmembrane domains of the G-protein-coupled receptor. Radioligand binding assays revealed undetectable levels of functional EDNRB in tissues from homozygous sl/sl rats. We conclude that EDNRB plays an essential role in the normal development of two neural crest-derived cell lineages, epidermal melanocytes and enteric neurons, in three mammalian species--humans, mice, and rats. The EDNRB-deficient rat may also prove valuable in defining the postnatal physiologic role of this receptor.

Effect of staining solutions and repolishing on color stability of direct composites

OBJECTIVES: The purpose of this study was to assess the color change of three types of composite resins exposed to coffee and cola drink, and the effect of repolishing on the color stability of these composites after staining. MATERIALS AND METHODS: Fifteen specimens (15 mm diameter and 2 mm thick) were fabricated from microhybrid (Esthet-X; Dentsply and Filtek Z-250; 3M ESPE) and high-density hybrid (Surefil; Dentsply) composites, and were finished and polished with aluminum oxide discs (Sof-Lex; 3M ESPE). Color of the specimens was measured according to the CIE L*a*b* system in a refection spectrophotometer (PCB 6807; BYK Gardner). After baseline color measurements, 5 specimens of each resin were immersed in different staining solutions for 15 days: G1 - distilled water (control), G2 - coffee, G3 - cola soft drink. Afterwards, new color measurement was performed and the specimens were repolished and submitted to new color reading. Color stability was determined by the difference (ΔE) between the coordinates L*, a*, and b* obtained from the specimens before and after immersion into the solutions and after repolishing. RESULTS: There was no statistically signifcant difference (ANOVA, Tukey's test; p>0.05) among the ΔE values for the different types of composites after staining or repolishing. For all composite resins, coffee promoted more color change (ΔE>3.3) than distilled water and the cola soft drink. After repolishing, the ΔE values of the specimens immersed in coffee decreased to clinically acceptable values (ΔE<3.3), but remained signifcantly higher than those of the other groups. CONCLUSIONS: No signifcant difference was found among composite resins or between color values before and after repolishing of specimens immersed in distilled water and cola. Immersing specimens in coffee caused greater color change in all types of composite resins tested in this study and repolishing contributed to decrease staining to clinically acceptable ΔE values.

Composite resin color stability: influence of light sources and immersion media

OBJECTIVE: This study evaluated the influence of light sources and immersion media on the color stability of a nanofilled composite resin. MATERIAL AND METHODS: Conventional halogen, high-power-density halogen and high-power-density light-emitting diode (LED) units were used. There were 4 immersion media: coffee, tea, Coke® and artificial saliva. A total of 180 specimens (10 mm x 2 mm) were prepared, immersed in artificial saliva for 24 h at 37±1ºC, and had their initial color measured with a spectrophotometer according to the CIELab system. Then, the specimens were immersed in the 4 media during 60 days. Data from the color change and luminosity were collected and subjected to statistical analysis by the Kruskall-Wallis test (p<0.05). For immersion time, the data were subjected to two-way ANOVA test and Fisher's test (p<0.05). RESULTS: High-power-density LED (ΔE=1.91) promoted similar color stability of the composite resin to that of the tested halogen curing units (Jet Lite 4000 plus - ΔE=2.05; XL 3000 - ΔE=2.28). Coffee (ΔE=8.40; ΔL=-5.21) showed the highest influence on color stability of the studied composite resin. CONCLUSION: There was no significant difference in color stability regardless of the light sources, and coffee was the immersion medium that promoted the highest color changes on the tested composite resin.

Evaluation of iris color stability in ocular prosthesis

Accurate iris reproduction in the fabrication of ocular prosthesis in order to match the remaining eye is a key factor to mask the loss and achieve an esthetic outcome for anophthalmic patients. This study evaluated the stability of acrylic paints used for replicating iris color in ocular prostheses by the analysis of two factors: the temperature of the acrylic resin polymerization cycle during prosthesis fabrication and the incidence of sun light, which is the main photodegrading agent undermining the longevity of ocular prostheses. An accelerated aging assay was used for both analyses. Specimens simulating the prosthetic iris in the colors blue, yellow, black, brown and green were fabricated, and were submitted to a colorimetric reading before and after undergoing the thermal conditions of acrylic resin polymerization. Next, the specimens were submitted to an artificial accelerated aging assay with ultraviolet radiation A and weekly colorimetric readings during a 3-week period. The color change (??*) values for the four specimens painted with the same color paint were averaged and the resulting values were considered for statistical analysis. Levine's test and Student's t-test were used to analyze the influence of the temperature of the polymerization cycle during prosthesis fabrication on the color stability of each acrylic resin paint. Friedman's test for three dependent samples was used for analysis of color photodegradation as function of time. Significance level was set at 0.05 for all analyses. It was observed that, after the action of the temperature of the polymerization cycle, alteration above clinically acceptable level of ??*> 3.3 was observed only for the yellow color. After the accelerated aging assay, there were statistically significant differences (p<0.05) as a function of time in the green, brown, black and blue colors. Changes were clinically acceptable for the brown and black colors; slightly above the clinically acceptable limit for the green color; and significantly high and impracticable from a clinical standpoint for the blue color. There was no statistically significant differences (p>0.05) for the yellow color, which presented color change only a little above the clinically acceptable limit. In conclusion: 1. Only the yellow color presented alterations above the clinically acceptable levels after the polymerization cycle; 2. After accelerated aging, there was no changes in the yellow color above the clinically acceptable levels; 3. For the green color, degradation was significant and slightly above the clinically acceptable levels; 4. The black, brown and blue colors presented significant alterations as function of time; the alterations of the brown and black colors were within acceptable clinical levels, while the blue color presented a more accentuated degradation over time.

Diagnostic agreement between panoramic radiographs and color doppler images of carotid atheroma

The aim of this study was to investigate the agreement between diagnoses of calcified atheroma seen on panoramic radiographs and color Doppler images. Our interest stems from the fact that panoramic images can show the presence of atheroma regardless of the level of obstruction detected by color Doppler images. Panoramic and color Doppler images of 16 patients obtained from the archives of the Health Department of the city of Valença, RJ, Brazil, were analyzed in this study. Both sides of each patient were observed on the images, with a total of 32 analyzed cervical regions. The level of agreement between diagnoses was analyzed using the Kappa statistics. There was a high level of agreement, with a Kappa value of 0.78. In conclusion, panoramic radiographs can help detecting calcifications in the cervical region of patients susceptible to vascular diseases predisposing to myocardial infarction and cerebrovascular accidents. If properly trained and informed, dentists can refer their patients to a physician for a cardiovascular evaluation in order to receive proper and timely medical treatment.

Wettability, Shrinkage and Color Changes of Araucaria angustifolia After Heating Treatment

The effects of thermal treatment on the wettability and shrink resistance of Araucaria angustifolia (Parana pine) were studied from 20 to 200 °C. The contact angles of water droplets on untreated and heat-treated samples were measured by the sessile drop method in the grain of heartwood and sapwood cut in the radial, longitudinal, and tangential directions. A significant increase of the contact angles was verified for the samples from room temperature to 120 °C, in particular in the radial and tangential directions; at higher temperatures, the contact angles assumed almost constant values. From 120 to 200 °C, the sapwood of Araucaria angustifolia showed better dimensional stability and lower thermal resistance when compared to the heartwood. Variations of color were also studied by using the CIELab system, which showed to be capable of accurately distinguishing samples treated at different temperatures.

Non-coding RNAs in schistosomes: an unexplored world

Non-coding RNAs (ncRNAs) were recently given much higher attention due to technical advances in sequencing which expanded the characterization of transcriptomes in different organisms. ncRNAs have different lengths (22 nt to >1, 000 nt) and mechanisms of action that essentially comprise a sophisticated gene expression regulation network. Recent publication of schistosome genomes and transcriptomes has increased the description and characterization of a large number of parasite genes. Here we review the number of predicted genes and the coverage of genomic bases in face of the public ESTs dataset available, including a critical appraisal of the evidence and characterization of ncRNAs in schistosomes. We show expression data for ncRNAs in Schistosoma mansoni. We analyze three different microarray experiment datasets: (1) adult worms' large-scale expression measurements; (2) differentially expressed S. mansoni genes regulated by a human cytokine (TNF-α) in a parasite culture; and (3) a stage-specific expression of ncRNAs. All these data point to ncRNAs involved in different biological processes and physiological responses that suggest functionality of these new players in the parasite's biology. Exploring this world is a challenge for the scientists under a new molecular perspective of host-parasite interactions and parasite development.

Color/race inequalities in oral health among Brazilian adolescents

This study assessed oral health outcomes (perceived dental treatment need, untreated dental caries, gingival bleeding, periodontal pockets, and pain in teeth and gums), in relation to color/race inequalities among adolescents in each Brazilian region. The database included dental examination and interview of 16,833 15-19-year-old adolescents, surveyed by the Brazilian health authority, from May 2002 to October 2003, in accordance with international diagnostic criteria standardized by the World Health Organization. Prevalence ratios estimated by Poisson regression, and controlled by socioeconomic status and access to fluoridated piped water, assessed oral health differentials among color/race groups and country's regions. Except for periodontal pockets, prevalence figures were higher in the North and Northeast: perceived dental treatment needs, untreated dental caries, gingival bleeding at probing and pain in teeth and gums varied between 80-83%, 75-76%, 38-43%, and 17-18%, respectively, in these regions. Adolescents living in the Southeast - the richest Brazilian region - presented a better general profile of oral health than their counterparts living in the remaining regions; they had a lower prevalence of untreated dental caries (54%) and unfavorable gingival status (29%). However, the Southeast presented color/race inequalities in all oral health outcomes, with a poorer profile systematically affecting browns or blacks, depending on the oral health condition under consideration. These results reinforce the need for expanding the amplitude of health initiatives aimed at adolescent oral health. Socially appropriate health programs should concurrently aim at the reduction of levels of oral disease and its inequalities.

The expression of genes coding for distinct types of glycine-rich proteins varies according to the biology of three metastriate ticks, Rhipicephalus (Boophilus) microplus, Rhipicephalus sanguineus and Amblyomma cajennense

Background: Ticks secrete a cement cone composed of many salivary proteins, some of which are rich in the amino acid glycine in order to attach to their hosts' skin. Glycine-rich proteins (GRPs) are a large family of heterogeneous proteins that have different functions and features; noteworthy are their adhesive and tensile characteristics. These properties may be essential for successful attachment of the metastriate ticks to the host and the prolonged feeding necessary for engorgement. In this work, we analyzed Expressed Sequence Tags (ESTs) similar to GRPs from cDNA libraries constructed from salivary glands of adult female ticks representing three hard, metastriate species in order to verify if their expression correlated with biological differences such as the numbers of hosts ticks feed on during their parasitic life cycle, whether one (monoxenous parasite) or two or more (heteroxenous parasite), and the anatomy of their mouthparts, whether short (Brevirostrata) or long (Longirostrata). These ticks were the monoxenous Brevirostrata tick, Rhipicephalus (Boophilus) microplus, a heteroxenous Brevirostrata tick, Rhipicephalus sanguineus, and a heteroxenous Longirostrata tick, Amblyomma cajennense. To further investigate this relationship, we conducted phylogenetic analyses using sequences of GRPs from these ticks as well as from other species of Brevirostrata and Longirostrata ticks. Results: cDNA libraries from salivary glands of the monoxenous tick, R. microplus, contained more contigs of glycine-rich proteins than the two representatives of heteroxenous ticks, R. sanguineus and A. cajennense (33 versus, respectively, 16 and 11). Transcripts of ESTs encoding GRPs were significantly more numerous in the salivary glands of the two Brevirostrata species when compared to the number of transcripts in the Longirostrata tick. The salivary gland libraries from Brevirostrata ticks contained numerous contigs significantly similar to silks of true spiders (17 and 8 in, respectively, R. microplus and R. sanguineus), whereas the Longirostrata tick contained only 4 contigs. The phylogenetic analyses of GRPs from various species of ticks showed that distinct clades encoding proteins with different biochemical properties are represented among species according to their biology. Conclusions: We found that different species of ticks rely on different types and amounts of GRPs in order to attach and feed on their hosts. Metastriate ticks with short mouthparts express more transcripts of GRPs than a tick with long mouthparts and the tick that feeds on a single host during its life cycle contain a greater variety of these proteins than ticks that feed on several hosts.

Report of a chimeric origin of transposable elements in a bovine-coding gene

Despite the wide distribution of transposable elements (TEs) in mammalian genomes, part of their evolutionary significance remains to be discovered. Today there is a substantial amount of evidence showing that TEs are involved in the generation of new exons in different species. In the present study, we searched 22,805 genes and reported the occurrence of TE-cassettes in coding sequences of 542 cow genes using the RepeatMasker program. Despite the significant number (542) of genes with TE insertions in exons only 14 (2.6%) of them were translated into protein, which we characterized as chimeric genes. From these chimeric genes, only the FAST kinase domains 3 (FASTKD3) gene, present on chromosome BTA 20, is a functional gene and showed evidence of the exaptation event. The genome sequence analysis showed that the last exon coding sequence of bovine FASTKD3 is similar to 85% similar to the ART2A retrotransposon sequence. In addition, comparison among FASTKD3 proteins shows that the last exon is very divergent from those of Homo sapiens, Pan troglodytes and Canis familiares. We suggest that the gene structure of bovine FASTKD3 gene could have originated by several ectopic recombinations between TE copies. Additionally, the absence of TE sequences in all other species analyzed suggests that the TE insertion is clade-specific, mainly in the ruminant lineage.

Color-flavor locked strange matter and strangelets at finite temperature

It is possible that a system composed of up, down, and strange quarks exists as the true ground state of nuclear matter at high densities and low temperatures. This exotic plasma, called strange quark matter (SQM), seems to be even more favorable energetically if quarks are in a superconducting state, the so-called color-flavor locked state. Here we present calculations made on the basis of the MIT bag model, considering the influence of finite temperature on the allowed parameters characterizing the system for stability of bulk SQM (the so-called stability windows) and also for strangelets, small lumps of SQM, both in the color-flavor locking scenario. We compare these results with the unpaired SQM and also briefly discuss some astrophysical implications of them. Also, the issue of the strangelet's electric charge is discussed. The effects of dynamical screening, though important for nonpaired SQM strangelets, are not relevant when considering pairing among all three flavors and colors of quarks.