Pattern Of Color Change Research Articles

Use of liquid crystals as temperature sensors in food processing research

Liquid crystal is a chemical compound which changes its color with temperature. It is useful in non-intrusively visualizing instantaneous surface temperature changes, where other conventional temperature sensors cannot be used. The thermal field visualization can either be (a) qualitative, by observing the pattern of color change, or (b) quantitative by calibrating it with a thermocouple at a known temperature range. The material is available in the temperature range of −30 °C to 115 °C. The minimum and average error values associated with the temperature measurement are 0.01 °C and 0.5 °C, respectively.

Phenotypic Variation in Australian Eurema Species

Australian butterflies in the tropical pierid genus Eurema (the grass yellows) exhibit seasonal phenotypic changes in both size and colour pattern. In four of the five species, smaller adults were present during the summer and autumn wet season than during the cooler winter-spring dry season. The fifth species, E. hecabe, showed the reverse pattern, being largest when it first appeared late in the wet season and becoming smaller as the dry season progressed. When reared in the laboratory, however, all five species produced larger adults when reared at lower temperatures, and at least two of the species also produced larger adults at shorter photoperiods. In the case of E. hecabe, juvenile overcrowding and resource limitation may prevent the potential size increase during the cooler dry season from occurring. All five species had darker markings during the cooler dry season, and in two of them, E. herla and E. laeta, there was also a change in the ground colour of the underwing from yellow to pink or brown. The darker markings may serve a thermoregulatory function, as in other pierids, but the change in colour probably functions to allow E. herla and E. laeta, which diapause as adults during the dry season, to be more cryptic as the grasslands they occupy dry off and change colour. In all species except E. herla, the range of variation in dark markings observed in the field could be reproduced in the laboratory by varying the temperatures and/or photoperiods at which the juvenile stages were reared (darker individuals were produced at lower temperatures and shorter photoperiods). The change in ground colour in E. herla and E. laeta, however, was not reproduced in laboratory rearings, either by changing photoperiod and temperatures, or by rearing animals at low humidities, suggesting that an additional cue may be needed to induce this shift in phenotype.

Evaluating blood flow in full-thickness skin grafts utilizing the laser Doppler.

Full-thickness skin grafts follow a consistent clinical pattern of color and textural changes. Measurements with the Laser Doppler Velocimeter correlate with these observed changes, yielding reproducible temporally associated blood flow rates. Previous physiologic and histologic studies for skin grafts are discussed.

Effect of contact-dehydrating sheet treatment on the color of bigeye tuna muscle.

A dehydrating device called contact-dehydrating sheet, is known to have an excellent capacity in dehydrating foodstuffs when it comes in contact with them. The effect of the sheet treatment on the color of bigeye tuna muscle was studied. Samples of 1.5cm thick were dehydrated by covering the sample slab with the sheet on the top side. After dehydrating for 5, 12h, 1, 2, 3 and 5 days at 3°C, each of the sample slabs wassliced horizontally along the treated side into 3 layers of equal thickness. It was found that the distribution of water removal in tuna muscle was more uniform than what occurred in beef and this uniformity might be due to less adipose and connective tissues. The ratio of metmyoglobin formation inupperlayerof dehydrated sample was the same with that of control and gradually increased with the prolonged treatment time. The iron content of samples rose from about 0.8 to 1.1mg% during the 5-day period dehydration. However, there was not much difference in redness of bigeye tuna muscle with the controls at varied iron content in this range. This phenomenon was thought to be due to the particular pattern of color (Mb) change in bigeye tuna muscle. This pattern was not significantly influenced by the formation of metmyoglobin.

Hybrid zones of Heliconius butterflies in Panama and the stability and movement of warning colour clines

Heliconius erato and H. melpomene are warningly coloured tropical butterflies that show mimetic covariation throughout the neotropics. Central American, West Colombian, and North Colombian colour pattern races of both species meet and form hybrid zones in Panama. These hybrid zones were sampled along a transect. The major colour pattern changes are determined by three alleles at a single locus in each species. There is no evidence for hybrid breakdown or mating incompatibility between any of the phenotypes in Panama, and local genotypic frequencies are not significantly different from Hardy-Weinberg expectation. I simulated a single-locus, two-allele warning colour hybrid zone (cline) with dominance. Predator selection on warning colour patterns was assumed to be frequency-dependent, so that, at any point in the cline, a rare phenotype has lower fitness than a common phenotype. Simulation shows that such a cline rapidly reaches a stable slope. Since the model does not depend on selection caused by the abiotic environment, the cline is positionally unstable. Even if the two phenotypes are equally fit “dominance drive” tends to increase the area in which the dominant allele is present. Differences in fitness of the phenotypes and density gradients can also cause cline movement. Hybrid zone movement might either be rapid enough to obliterate patterns that were formed in Pleistocene refugia, or so slow as to make secondary contact a requirement for the existence of hybrid zones. A third possibility is that local variations in population density will normally prevent hybrid zone movement, even if this is potentially rapid. Better estimates of dispersal and selection are needed to resolve this issue.

Adaptations of the reed frog Hyperolius viridiflavus (Amphibia, Anura, Hyperoliidae) to its arid environment : I. The skin of Hyperolius viridiflavus nitidulus in wet and dry season conditions.

Hyperolius viridiflavus nitidulus inhabits parts of the seasonally very hot and dry West African savanna. During the long lasting dry season, the small frog is sitting unhidden on mostly dry plants and has to deal with high solar radiation load (SRL), evaporative water loss (EWL) and small energy reserves. It seems to be very badly equipped to survive such harsh climatic conditions (unfavorable surface to volume ratio, very limited capacity to store energy and water). Therefore, it must have developed extraordinary efficient mechanisms to solve the mentioned problems. Some of these mechanisms are to be looked for within the skin of the animal (e.g. protection against fast desiccation, deleterious effects of UV radiation and overheating). The morphology of the wet season skin is, in most aspects, that of a "normal" anuran skin. It differs in the organization of the processes of the melanophores and in the arrangement of the chromatophores in the stratum spongiosum, forming no "Dermal Chromatophore Unit". During the adaptation to dry season conditions the number of iridophores in dorsal and ventral skin is increased 4-6 times compared to wet season skin. This increase is accompanied by a very conspicuous change of the wet season color pattern. Now, at air temperatures below 35° C the color becomes brownish white or grey and changes to a brilliant white at air temperatures near and over 40° C. Thus, in dry season state the frog retains its ability for rapid color change. In wet season state the platelets of the iridophores are irregularly distributed. In dry season state many platelets become arranged almost parallel to the surface. These purine crystals probably act as quarter-wave-length interference reflectors, reducing SRL by reflecting a considerable amount of the radiated energy input.EWL is as low as that of much larger xeric reptilians. The impermeability of the skin seems to be the result of several mechanisms (ground substance, iridophores, lipids, mucus) supplementing each other.The light red skin at the pelvic region and inner sides of the limbs is specialized for rapid uptake of water allowing the frog to replenish the unavoidable EWL by using single drops of dew or rain, available for only very short periods.

Female Color Change in the Keeled Earless Lizard, Holbrookia propinqua: Relationship to the Reproductive Cycle

The orange and yellow coloration of female Holbrookia propinqua appears to be closely associated with ovarian events, intensifying rapidly during the final stages of vitellogenesis and reaching maximum brightness prior to ovulation. All females having recent corpora lutea or bearing oviducal eggs retained bright colors. Females with the dullest colors lacked orange and yellow pigmen- tation, had relatively small follicles, and were at early stages of the reproductive cycle. Further studies are needed to determine the course of chromatic variation between successive reproductive cycles and to evaluate the turn-on and turn-off hypotheses of the adaptive value of the female reproductive colora- tion. Distinctive changes in color pattern associated with reproduction occur in female iguanid lizards of several genera, including Crotaphytus (Cooper and Ferguson, 1972a, 1972b, 1973),Holbrookia (Clarke, 1965; Judd, 1973), Gambelia (Medica et al., 1975) and Sceloporus (Dixon, 1957). Female reproductive colora- tion may be induced by progesterone or testosterone injections and its onset may be hastened by estrogen injection in Crotaphytus collaris (Cooper and Ferguson, 1972a, 1972b, 1973) and Gambelia wislizeni (Medica et al., 1973). Although a hormonal basis for pigment depositions is well established, possible roles of the colors in reproductive behavior remain speculative and little is known regarding the relationships of the colors to reproductive cycling. Gravid females often show the most intense pigmentation (Judd, 1976; Fitch, 1956; Medica et al., 1973), usually orange to red, but the timing of pigment deposition with respect to courtship, copulation, follicular development, oviposition, and luteal activity remain largely unknown in most species. Only in Crotaphytus and Gambelia have some of these relationships been studied. Female C. collaris develop orange lateral spots, changing from a dull, non-breeding pattern to maximum birght- ness in a single day. This rapid color change occurs in preovulatory females approximately 10-13 days before oviposition (Ferguson, 1976; Fitch, 1956). Max- imal color intensity in G. wislizeni is also established during vitellogenesis, prior to ovulation (Medica et al., 1973). In this paper, intensity of orange and yellow pigmentation is correlated with reproductive state in the keeled earless lizard, Holbrookia propinqua, and impli- cations of this relationship for hypotheses about the adaptive significance of the coloration are discussed.

Gonad morphology and sex succession in the protogynous hermaphrodite Hemanthias vivanus (Jordan and Swain)

Hemanthias vivanus, an anthiine serranid common on deep (70–80 m) reefs off eastcentral Florida, is shown to be a protogynous hermaphrodite with observed size ranges as follows: female, 49–77 mm S.L.; transitional 65–74; male, 65–96. Sexes are distinguishable externally as the dorsal spine filaments elongate and colour pattern changes with sex succession. In females, lamellae extend from the lateral and dorsal walls of the bilobed ovary into the lumen. Ova mature within the lamellae and at ovulation pass centrally into the lumen, posteriorly into a common post‐ovarian sinus, and exit through the oviduct. Females possess a discrete tissue band (testicular islets) at the border of the alamellar region, from which testicular tissue proliferates during sex succession and replaces the regressing ovarian tissue. In males, spermatozoa are formed in crypts which drain peripherally into a sperm sinus which forms by rupture of muscular and connective tissue layers surrounding the gonad. The sperm sinus drains posteriorly into the vas deferens which is formed by rupture of collagenous tissue surrounding and posterior to the now vestigial post‐ovarian sinus. The vas deferens and mesonephric duct join within the urogenital papilla. Two smooth muscle bands associated with the infracarinalis medius muscle bands, the collagenous tissue surrounding the gonoduct, and the intestinal lining are implicated in the extrusion of gametes, urine and faeces. At sex succession, ova are resorbed in one of at least three pathways depending upon their stage of development at the onset of sex transformation: unovulated mature ova become encysted with fibroblasts and invaded by cells of an unknown origin; non‐mature yolky ova are invaded and phagocytized by granulosa cells; non‐yolky ova are not invaded but fragment.

Complex Color Changes in Anolis (Reptilia, Lacertilia, Iguanidae)

A complex pattern of color changes is described for Anolis coelestinus involving three basic background colors-gray, green, and brown-and three types of patterns- solid, striped, and mottled. This complex set of changes within one individual cannot be explained given the models and mechanisms for color change described for Anolis carolinensis. In addition, the change from green to brown occurs with the brown being stippled in, suggesting all-or-nothing responses of sets of regularly distributed melanophores. The differential occurrence of the patterns in differing habitat situations indicates camouflage as a primary function in females and juveniles. The frequent use of bright green by male A. coelestinus and the use of a peculiar green/orange pattern by a male A. distichus vinosus emphasize the importance of conspicuous color patterns in male advertisement. * * *

The small nymphs of Diura nanseni (Kempny) (Plecoptera)

AbstractA description of the development of the maxilla and the changes in colour pattern of the immature nymphs of the stonefly Diura nanseni is given. The maxillae of these nymphs differed from the description given for larger nymphs used in keys. The colour pattern of these nymphs was also different.

Color Pattern Changes with Increasing Size in the Western Atlantic Trunkfish Lactophrys trigonus

Color Pattern Changes with Increasing Size in the Western Atlantic Trunkfish Lactophrys trigonus

New sharks from the South China Sea*

Three new species and one new genus of sharks are described from the South China Sea. Cephaloscyllium fasciatum sp. n. (Scyliorhinidae) has a distinctive colour pattern characterized by the presence of dark‐edged blotches and saddles; and by the lobe‐like anterior nasal flap. The colour pattern and certain developmental changes in C. umbratile Jordan and Fowler are discussed. Dichichthys melanobranchus gen. n. and sp. (Scyliorhinidae) combines the distinguishing characters of three distinct genera: Galeus Rafinesque, Parmaturus Garman, and Apristurus Carman. This suggests that Dichichthys may be an ancestral form from which these three genera have evolved. Etmoptems decacuspidatus sp. n. (Squalidae) is distinguished primarily on the basts of the decacuspid teeth to the upper jaw; this unusually high number of cusps is shown not to have been acquired as a result of old age.The vertebral characters of all species are studied radiographically.

Pattern of Color Change Emerges from 3-Year Storage Study of Cotton Grades

Pattern of Color Change Emerges from 3-Year Storage Study of Cotton Grades

A Comparison of the Larvae of Five Northeastern Species of Ambystoma (Amphibia, Caudata)

regularly metamorphoses throughout its geographic range and has a life history adjusted to summer rains characteristic of western Mexico. The variation and ontogenetic changes in color pattern have particular reference to their use in the systematics of rosaceum and related forms. It is suggested that A. fluvinatum, A. rosaceum nigrum and A. r. sonoraensis be relegated to the synonymy of A. rosaceum since all of the characters utilized to distinguish these forms were based on larvae and fall within the range of population and age variation in large series of rosaceum larvae from Chihuahua and Durango.

Gamma irradiation of potatoes: Effects on sugar content, chip color, germination, greening, and susceptibility to mold

Russet Burbank potatoes that had been stored at 40°F. for 5 months after harvest were irradiated with 5,200 and 14,000 rad of Co60 gamma rays. In general, irradiation caused an accumulation of sugars. At 40°F., the sucrose level rose to nearly 3 times that of the control in 16 days following irradiation. Fructose and glucose showed smaller increases and the latter did not accumulate significantly in the tubers given the higher dose of gamma rays. At 70°F., the levels of sucrose and glucose in the irradiated tubers rose above those in the controls, the difference reaching a maximum in 4 days and then declining. Irradiation had no effect on loss of fructose at this temperature. Color of potato chips processed from the irradiated potatoes was in general darker than that of chips from control tubers. The storage-time pattern of color change resembled that of the reducing rather than total sugar. Fourteen thousand rad did not prevent initiation of germination in the tubers but did destroy their sprout-growth apparatus. Although the lower dosage did not prevent initiation and subsequent growth, it prevented the formation of secondary tubers, which appeared on the sprouted control tubers. Furthermore, unlike the controls, the low-dosage potatoes developed branching hair sprouts with no tendency toward apical dominance during the early stages of sprouting. The rate of greening of gamma-irradiated and illuminated tubers was significantly less than that of unirradiated illuminated controls. Evidence is presented that irradiation may increase the susceptibility of potatoes to attack by molds under some conditions.

The pigment changes in frog larvae deprived of the epithelial hypophysis

It has been known for a considerable time that in the fishes, amphibia and reptilia remarkable changes in color pattern or external appearance occur. It is also generally known that these effects are due to the reciprocal interplay of alterations in at least two great systems of pigment-bearing cells, the bearers of dark pigment (melanophores) and the bearers of various other pigments, many of them metallic lustered (xantholeucophores). To the latter class of pigments the trout owes its silvery appearance. Somewhat over two years ago the author, followed shortly by B. M. Allen, showed that peculiar silvery frog larvæ were invariably produced when the epithelial portion of the hypophysis was removed in early embryonic stages. For the sake of brevity these individuals were designated “albinos” and are always in conspicuous contrast to the darker, normal specimens. As might be expected from our introductory remarks, both of the great groups of pigment-bearing cells contribute to produce this strange effect; but no mention of the iridescent cells (the xantholeucophores) was made by the writer at the time of his early communications on this subject and it is noteworthy that in both of the subsequent papers by B. M. Allen and in the recent communication by W. J. Atwell these cells have received no attention whatever. It can be demonstrated easily that the silvery, or albinous, condition, as is the case in so many instances of the color change in animals, is participated in by both groups of cells, melanophores and xantholeucophores. Furthermore, it is indeed a fact that under normal conditions no change in the condition of one of these sets of cells takes place without a reciprocal alteration in the other. This conception was forced home to the writer not merely by a reexamination of the anatomical causes for the albinos, but by extensive physiological and pharmacological experiments on normal and albinous specimens.