White Pigmentation Research Articles

Molecular phylogenetics of Fouquieriaceae: evidence from nuclear rDNA ITS studies

Molecular sequence data from the 18S-26S rDNA internal transcribed spacer (ITS) region support the monophyly of Fouquieria sensu lato (Fouquieriaceae) and the three subgenera (subg. Fouquieria, subg. Bronnia, subg. Idria) previously recognized within it. Resolution within subg. Fouquieria differs somewhat between parsimony and maximum likelihood (ML) trees. Section Fouquieria and sect. Ocotilla within subg. Fouquieria are not well supported as monophyletic groups. Uncertainty regarding placement of the root within Fouquieriaceae makes discussion of character evolution within the family difficult. Three root positions are consistent with rate-constant evolution of ITS sequences: (1) along the branch to subg. Idria, (2) along the branch to subg. Bronnia, and (3) along the branch to subg. Fouquieria. The first root position listed is equivalent to an outgroup rooting. The third root position listed is equivalent to a midpoint rooting. Of the three root positions above, only the third is along a branch that may be sufficiently long to act as a long-branch attractor. The first two root positions would result in character reconstruction suggesting that succulent growth forms and white floral pigmentation are ancestral within the family, with shifts to woody growth forms and to red floral pigmentation. The third root position results in equivocal reconstruction of the ancestral growth form, equivocal reconstruction of ancestral floral pigmentation in parsimony trees, and a suggestion of white floral pigmentation as ancestral in ML trees. Two previous hypotheses of polyploid origins are compatible with the molecular data presented here: (1) origin of the tetraploid F. diguetii from F. macdougalii, and (2) allopolyploid origin of the hexaploid F. burragei from the tetraploid F. diguetii and a diploid species similar to F. splendens. Direct descent of the hexaploid F. columnaris from the subg. Bronnia lineage is not supported by our data. An amphiploid origin of F. columnaris involving a member of the subg. Bronnia lineage and an extinct taxon outside subg. Bronnia, however, cannot be ruled out.

Geographical dispersal and optimum release size of hatchery-reared Japanese flounder Paralichthys olivaceus released in Ishikari Bay, Hokkaido, Japan

The dispersal and optimum release size of Japanese flounder stocked in Ishikari Bay, the most northern area where fry was stocked, were examined by tagging and marking experiments and market surveys of commercial landings. In Ishikari Bay, 17,055 tagged flounder (mean TL = 13 cm) were released in September 1988, and 59,600 (mean TL = 8 cm) and 72,900 (mean TL = 6 cm) fin-clipped flounder were stocked between July and August 1989. Hatchery-reared flounder have an abnormal white and black pigmentation on the anocular side, which easily distinguishes them from wild flounder. The recovery rate of a released group of flounder with an average length of 8 cm (8.2%) was 2.4 times that of a group with an average length of 6 cm (3.2%). In the tagging experiment, a total of 330 (1.9%) recoveries were recorded between October 1988 and November 1991. The tagging experiment showed that the distribution of the stocked flounder extended southward to the Tsushima Current; no fish were recaptured to the north of the release site. The numbers of stocked flounder in the landings decreased with increasing distance from the release area and 75% of recaptured flounder were caught within Ishikari Bay. The tagging experiment also showed that 68% of the fish which recruited to the fishery at ≥25 cm TL were captured inside Ishikari Bay.

Uric Acid in Anopheles Mosquitoes (Diptera: Culicidae): Effects of Collarless, Stripe, and White Mutations

Anopheles mosquito larvae and pupae often have a layer of white pigment visible beneath the transparent cuticle on the dorsum of the abdomen and thorax. This pigment occurs in granules that are highly concentrated in ameboid-shaped cells of the parietal fat body. Mutations that affect the pattern or abundance, or both, of this pigment in A. albimanus Wiedemann and A. gambiae Giles are characterized by differences in the abundance of uric acid, whose levels range from 1.86 to 3.13 μg per larvae in individuals of 4 phenotypes having white pigmentation. Uric acid concentrations are higher in A. albimanus stripe + individuals which also have the most prominent white pigment. Two other mutants, A. gambiae collarless and A. albimanus white eye, contain no detectable uric acid nor any white pigment. None of the mutants examined has reduced xanthine dehydrogenase activity nor altered XDH electrophoretic mobility. We suggest that the prominent white pigment is precipitated uric acid contained within specialized fat-body cells similar to urocytes. We discuss the genetic basis of mutants affecting uric acid deposition, and the pleiotropic effects of the eye-color mutations such as white.

Treatment with propionic and butyric acid enhances expression variegation and promoter methylation in plant transgenes.

Two phenotypic marker genes (A1 and GUS) were employed to monitor the influence of small chain fatty acids on transgene expression in petunia and tobacco. In plants homozygous with respect to the A1 transgene, which normally carry red flowers due to A1 expression, fatty acid treatment induced a range of variegated and white pigmentation patterns which persisted for several months after terminating the treatment. The inhibitory effect was clearly less pronounced for heterozygous plants of the same transgenic line. In all cases the reduction of transgene activities correlated with an increase in transgene promoter methylation. Contrary to evidence reported for mammals and Drosophila, we do not observe an increase in gene expression, but an enhancement of DNA methylation and epigenetic variegation. The inhibition of transgene activity was also observed in several tobacco transformants cultured on fatty acid containing media. Some tobacco transformants carrying Gus-coding regions driven by either 35S or 1'2' promoters responded with a significant reduction in GUS activity. This study suggests that, rather than exerting a general response on all chromatin regions, fatty acids appear to affect genes in a labile epigenetic surrounding or all genes in a susceptible chromatin configuration. Thus, application of these agents may be useful to screen and monitor transgenes prone to epigenetic instabilities.

Two New Species of Centrolenid Frogs from the Amazonian Slope of the Cordillera Oriental, Ecuador

Two new species of centrolenid frogs are described from the Amazonian slopes of the Cordillera Oriental of the Andes in Provincia Morona-Santiago, Ecuador. The first species is a member of the Centrolene prosoblepon group and is distinguished from all other members of the group by having a lateral row of large enameled tubercles that extends from below the eye to just posterior to the insertion of the arm. The condition of the humerus was compared with that of other species of the C. prosoblepon group from Ecuador and was found to be most similar to the condition of C. audax. The second species is a member of the Cochranella ocellata group and is distinguished from all other members of the group by possessing white visceral pigmentation on the esophagus, a first finger shorter than second, and lacking vomerine teeth

Pigmented and transparent, highly impact‐resistant PVC for outdoor use

AbstractBased on the high standard of quality of EVA‐modified PVC, Hüls has developed an impact‐modified acrylate‐base PVC which can be processed over a wider range, thus meeting the high demands made with regard to processability.The excellent light stability and resistance to weathering of this material, with its technological properties being retained at the same time, were achieved in white and brown pigmentation within a wide range of stabilizations. This is supported by comprehensive findings from open‐air weathering stations located in various climate zones as well as by findings obtained from Weather‐Ometer and QUV testing.One phenomenon which has been observed in connection with white‐pigmented PVC, but which has been accorded little attention in the technical literature, is the discolouring of weathered samples when stored in a dark room. This phenomenon, which can also be simulated in a Weather‐Ometer, has an impact on the evaluation of PVC materials for out door usage and of ten leads to false conclusions.In addition to this pigmented, impact‐resistant PVC Hüls has also developed a highly transparent, impact‐resistant PVC for out door use which is also acrylate‐modified. Here the selection of stabilizers and of the graft copolymer is limited from the beginning due to the high demands made with regard to the technological properties of the final product, i.e. light stability and resistance to weathering, high transparency as well as impact resistance. Despite this, Hüls has been successful in developing an impact‐modified graft polymer which, when suitably compounded, meets the exacting requirements made by the market.

Predation, thermoregulation, and wing color in pierid butterflies.

This paper explores two hypotheses about the relationships among predation, thermoregulation, and wing color in butterflies: First, that butterflies are susceptible to predation during thermally marginal periods (e.g., cool weather) when effective thermoregulation and flight are not possible; second, that Pieris butterflies are relatively unpalatable to visual predators, supporting the idea that the white wing pigment of Pieris represents aposematic coloration. Field experiments with Pieris and Colias in 1984 and 1985 demonstrate that substantial predation may occur during the morning period before butterflies are able to actively fly. Circumstantial evidence is presented to suggest that at least some of the predation is by small, cursorial mammals. Feeding experiments in the field using Grey Jays as predators indicate that Pieris napi and P. occidentalis are less palatable than other sympatric butterflies, including confamial Colias alexandra. These and previous results suggest that Pieris are edible but less preferred as prey by birds, and that the degree of palatibility may vary among Pieris species. The relatively low palatability of these Pieris is consistent with the hypothesis that their white pigmentation represents aposematic coloration; however, the cues by which potential bird predators might discriminate against Pieris have not been established.

Factors affecting perithecial production in Gibberella (Fusarium) tricincta

Three pigmentation types (brown, red, and white) of Fusarium tricinctum (Corda) Sacc. were observed when an isolated mass culture from leaf spots on English ivy (Hedera helix L.) was single spored. Perithecia of the heterothallic fungus Gibberella tricincta El-Gholl were produced at 20 and 27 °C on stem pieces of Cynodon dactylan Pers. resting on water agar, under 12-h alternating light and dark when certain pigmentation types were paired. Pairing of red and brown pigmentation types yielded significantly (P < 0.05) more perithecia than red and white pairings at 20 and 27 °C. Perithecia were formed only in combinations of red with brown or white pigmentation types. In both sets of pairings, significantly (P < 0.05) more perithecia were produced at 27 than at 20 °C. No perithecia were formed in constant darkness. Occasionally, the red pigmentation type became white after subsequent transfers and never reverted to the red pigmentation on various media and failed to produce perithecia with any pigmentation type. Continuous darkness slightly favored red pigment formation over continuous light as detected by the Munsell color codes. Increasing temperatures from 20 to 32 °C decreased the colony growth diameter of the red-pigmented cultural type. At 32 °C a change in hue was noted with corresponding changes in color codes. Red mycelial pigmentation was intensified by the addition of copper, iron, manganese, and zinc to a basal medium. The addition of 0.1% yeast extract favored mycelial development and caused a more pronounced red mycelial pigmentation in the presence of heavy metals.

Inheritance of tip sterility in relation to auricle pigmentation and waxy bloom in three crosses of hexaploid wheat (<i>Triticum aestivum</i> L.)

Two Bangladeshi varieties, Aghrani and Ananda were found with normal spikes, pink auricle and non-waxy blooms. The variety Akbar resembled these characters except the auricle colour, where it was white. On the contrary, the selected line FM-147 was found with tip sterile, white auricle, and waxy bloom characters. The F1s in three different crosses (AG × FM-147, AN × FM-147) were found with normal spikes, white auricle, and non-waxy bloom. The F1 population of three crosses were found to segregate in the proportion of 3:1 with normal and tip sterile plants. Backcross progenies were found to segregate into 1:1 ratio with normal and tip sterile plants. These results indicated that a recessive gene controls the tip sterility. The auricle pigmentation in F2s of the crosses between AG × FM-147 and AN × FM- 147 was found to show the ratio 3:1 with auricle of pink and white pigmentation. Backcross progenies showed also the ratio 1:1. The inheritance of auricle pigmentation was also found to be governed by a single recessive gene. The F2s in three crosses showed the ratio 3:1 with waxy bloom and non- waxy bloom. Backcross progenies showed also the ratio 1:1 for these two characters. The F2 populations for two characters at a time were found to segregate into a dihybrid ratio of 9:3:3:1 indicating the absence of any linkage between these two characters. Keywords: Inheritance; tip sterility; hexaploid wheat. DOI: 10.3329/bjar.v35i3.6460Bangladesh J. Agril. Res. 35(3) : 535-541

A stripe character in Anopheles albimanus (Diptera: Culicidae) and its linkage relationships to sex and dieldrin resistance.

A strain of Anopheles albimanus Wiedemann with a mutant character involving a dorsal white stripe on the thorax and abdomen of larvae, pupae and adults was selected from field populations originating in Haiti. Genetic crosses with a nonstriped strain indicated that the stripe character is controlled by a single semidominant autosomal gene, varying in expressivity in the heterozygote in width of the stripe and intensity of white pigmentation. Toxicological tests with dieldrin on the larvae provided evidence that the genes for stripe and dieldrin resistance are situated on the same chromosome.