MELANIN AND URATE ACT TO PREVENT ULTRAVIOLET DAMAGE IN THE INTEGUMENT OF THE SILKWORM,BOMBYX mori

The phenomenon that epidermal cells under the white stripes rather than black stripes contain many uric acid granules was found in larvae of several Lepidopteran species. However, the biological mechanism of this phenomenon is still unknown. In the present study, we take advantage of several silkworm (Bombyx mori) body color mutant strains to investigate the deposition patterns and biological mechanism of urate and melanin in the integuments of these mutant larvae. By imaging with transmission electron microscope, we found that there were some melanin granules in the larval cuticle in black body color mutant plain Black (p^B), but not in background strain plain (p) with white larval body color. In contrast, the larval epidermal cell of background strain had much more urate granules than that of black one. Furthermore, the uric acid content under the black stripes was significantly lower than that under the white stripes in a single individual of mottled stripe (p^S) with black and white stripes in each segment. Ultraviolet A (UVA) exposure experiments showed that the distinct oily (od) mutant individuals with translucent larval integument were more sensitive to the UVA damage than black body color mutant and background strain without any pigmentation in the larval cuticle. This is likely due to the absence of melanin granules and few urate granules in the integument of od mutant. Thus, both the deposited melanin granules in the cuticle and the abundant urate granules in the epidermis cells constitute effective barriers for the silkworm to resist UVA‐induced damage.     

Television Viewing Is Not Predictive of BMI in Black and Hispanic Young Adult Females

Previous studies have observed that television (TV) viewing is predictive of obesity and weight gain. We examined whether the cross‐sectional association between TV viewing and BMI varied by racial/ethnic subgroups among young women in Wave III (collected in 2001–2002) of the National Longitudinal Study of Adolescent Health. We used multivariate linear regression to examine the relationship between TV viewing and BMI among 6,049 females while controlling for sociodemographic and health attributes. We stratified the sample by race/ethnicity to better understand the association between TV viewing and BMI across different groups. Black and Hispanic females had higher BMIs (black: 28.5 kg/m², Hispanic: 27.3 kg/m², white: 26.0 kg/m²) than white females, while black females reported higher numbers of hours spent watching TV (black: 14.7 h/week, Hispanic: 10.6 h/week, white: 11.2 h/week) when compared to their white and Hispanic peers. TV viewing was positively associated with BMI (β = 0.79, P = 0.003 for 8–14 vs. ≤7 h/week; β = 1.18, P = 0.01 for >14 vs. ≤7 h/week) independent of race/ethnicity, age, maternal education, history of pregnancy, parental obesity, and household income. However, in models stratified by race/ethnicity, increased TV viewing was associated with increased BMI only among white females; TV viewing was not predictive of higher BMI in black or Hispanic young adult females. Among black and Hispanic females, counseling to decrease TV viewing may be important but insufficient for promoting weight loss.     

Response of alate aphids to green targets on coloured backgrounds

To study the effect of background colour on aphid landing on green targets (water pan traps), two field experiments were set up in Hessen, Germany, in 2003. Traps were put onto coloured plastic sheets (13 colours, straw mulch, transparent foil, and uncovered soil, Experiment 1). In Experiment 2, green water pans were again put on coloured plastic sheets (red, white, green, and yellow), and the sheets were either sprayed with insect glue or not. Backgrounds and traps were spectrally characterised with a field radiometer (320–950 nm). Aphid catches were highest in the traps on the uncovered background, and lowest in the traps on white or silver backgrounds. For Brevicoryne brassicae, Myzus persicae (Homoptera: Aphididae, Macrosiphini) and five further aphid species, there was a significant negative correlation between UV‐reflectance (320–400 nm) and log(N + 1)‐transformed number of individuals. However, the effect of straw mulch (reduced aphid catches with straw compared to the uncovered background), could not be attributed to differences in UV‐reflectance, as UV was almost identical in soil and straw. High numbers of alate aphids were caught in traps with dark backgrounds (e.g. black, dark green), a result which was attributed to the high contrast between the background and target. The substantially higher aphid numbers from targets with bare soil than from targets with spectrally similar black backgrounds were thought to be caused by the structure of the background surface: for alate aphids, landing close to the target on smooth surfaces may induce probing, and the lack of appropriate substrate will result in take‐off, whereas soil will not induce probing, and aphids will continue to move towards the green targets.     

On classifying race in Brazil: Example from a study of the functional ability of older people (60+)

Abstract

How should race be categorized? This article investigates the usefulness of having three categories to describe a black‐white racial continuum, focusing on Brazil and the functional ability of elderly (60+) people there. Ironically, even as the U.S. census has started to acknowledge mixed race again, much social research in Brazil has begun not to. Using 1998 national household survey microdata (PNAD) for Brazil, we find it advantageous to use a three‐category scheme that separates a mixed black‐white (pardo) status from black or white when examining the functional ability of elders. We also find the tantalizing possibility of a crossover in which browns actually have more functional ability than white counterparts after controlling for many demographic, geographic, and socioeconomic factors.     

Come to the dark side: habitat selection of larval odonates depends on background visual patterns

1. Determining which environmental traits enable animals to inhabit and choose preferred habitats is key to understanding ecological processes. Habitat complexity and background colour patterns can act as selective pressures on animal behaviour, and ultimately affect habitat choice. 2. To investigate the role of environmental features on habitat selection, this study looked at whether dragonfly and damselfly larvae show a preference between dark/light or complex environments. Last‐instar larvae of Micrathyria didyma (Odonata: Libellulidae) and Acanthagrion lancea (Odonata: Coenagrionidae) were collected in the Neotropical savanna, and five experiments in laboratory conditions were subsequently carried out. The first experiment tested the preference of larvae for leaves in contrast to a white background. The second experiment compared a preference for white and black backgrounds. As both experiments showed a significant preference for darker backgrounds, a predator was included in the black background in the third experiment, and a macrophyte was included in the white background in the fourth experiment. In this way, favourable and unfavourable conditions were included in the habitat of choice. The fifth experiment tested the influence of environmental complexity on habitat choice. 3. The results of these experiments showed that larvae choose darker backgrounds independently of predation risk, and that macrophytes are as attractive as a dark background. They also suggest that the coenagrionid, but not the libellulid, prefer more complex environments. 4. Overall, these findings suggest that larvae exhibit behavioural preferences for background colour and complexity, which may ultimately drive habitat occupation.     

Landing response of Aedes (Stegomyia) polynesiensis mosquitoes to coloured targets

Aedes polynesiensis Marks (Diptera: Culicidae) is the primary vector of lymphatic filariasis (LF) in the island countries and territories of the South Pacific. In the development of a novel control tool, the response of Ae. polynesiensis to six different colours (three solid fabrics, two patterned fabrics and a plastic tarp) was measured using a digital photographic system. Adult mosquitoes were placed into an environmental chamber and allowed to choose between a white target and one of six experimental targets. Mosquito landing frequency and landing duration were calculated. Adult female Ae. polynesiensis preferred all of the experimental targets to the white control target. Mosquito landing frequency was highest for the solid targets (black, navy blue and red) followed in turn by the two colour pattern targets and the polyethylene target. Mosquito landing duration was greater for experimental targets when compared with white control targets. Mosquito landing frequencies did not change over time during the course of the assay. The response of male Ae. polynesiensis was also measured when exposed to a 100% cotton black target. Male mosquitoes preferred the black target to the white control target, although at levels lower than that observed in female mosquitoes. The results suggest that future investigations evaluating the visual responses of Ae. polynesiensis mosquitoes are warranted, with a special emphasis on semi‐field and field‐based experiments.     

Coho Salmon (Oncorhynchus kisutch) Prefer and Are Less Aggressive in Darker Environments

Fish are capable of excellent vision and can be profoundly influenced by the visual properties of their environment. Ambient colours have been found to affect growth, survival, aggression and reproduction, but the effect of background darkness (i.e., the darkness vs. lightness of the background) on preference and aggression has not been evaluated systematically. One-hundred Coho salmon (Oncorhynchus kisutch), a species that is increasing in popularity in aquaculture, were randomly assigned to 10 tanks. Using a Latin-square design, every tank was bisected to allow fish in each tank to choose between all the following colour choices (8 choices in total): black vs. white, light grey, dark grey, and a mixed dark grey/black pattern, as well as industry-standard blue vs. white, light grey, dark grey, and black. Fish showed a strong preference for black backgrounds over all other options (p < 0.01). Across tests, preference strength increased with background darkness (p < 0.0001). Moreover, having darker backgrounds in the environment resulted in less aggressive behaviour throughout the tank (p < 0.0001). These results provide the first evidence that darker tanks are preferred by and decrease aggression in salmonids, which points to the welfare benefits of housing farmed salmon in enclosures containing dark backgrounds.     

Spatial and temporal dynamics of oviposition behavior of bollworm and three of its predators in Bt and non-Bt cotton fields

Host plants exhibiting insect resistance traits have long been known to influence within‐plant distributions of pests and their natural enemies. Sites and timing of egg deposition are particularly important for synchrony of predators and their prey in the field. Temporal and spatial distribution of eggs of the cotton bollworms [Heliothis virescens (F.) and Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae)] and that of the predators Geocoris punctipes (Say) (Heteroptera: Geocoridae), Chrysoperla rufilabris (Burmeister) (Neuroptera: Chrysopidae), and Micromus spec. (Neuroptera: Hemerobiidae) were determined during three cotton seasons, from 2002 to 2004, by collecting and examining plants throughout each season. Comparisons also were made between Bt and non‐Bt cotton to investigate possible changes in oviposition behavior on Bt cotton. The study was conducted in commercial fields with insecticide use to manage pests when economic thresholds were exceeded in both cotton types. Egg densities for predators and bollworms varied among years, but were similar on Bt and non‐Bt cottons. Oviposition of bollworms and G. punctipes correlated spatially within plants, with most eggs laid on structures in the top five nodes of cotton plants and on the three outermost leaves on lateral branches regardless of cotton type. Bollworm oviposition dynamics exhibited two peaks within the season (early July and early August). Eggs of all predators and bollworms collected from the field and incubated in the laboratory had high hatching rates throughout each season (74–100%). Temporal association of predator with bollworm oviposition showed a significant correlation with green lacewings, a delay of 10 days for big‐eyed bugs, and no correlation with brown lacewings. Furthermore, Bt cotton plants exerted no significant effect on temporal or spatial patterns of oviposition of bollworms or the predators, indicating no change in oviposition behavior of bollworm females within plant structures after almost one decade of widespread planting of Bt cotton.     

Up‐regulation of GhTT2‐3A in cotton fibres during secondary wall thickening results in brown fibres with improved quality

Brown cotton fibres are the most widely used naturally coloured raw materials for the eco‐friendly textile industry. Previous studies have indicated that brown fibre pigments belong to proanthocyanidins (PAs) or their derivatives, and fibre coloration is negatively associated with cotton productivity and fibre quality. To date, the molecular basis controlling the biosynthesis and accumulation of brown pigments in cotton fibres is largely unknown. In this study, based on expressional and transgenic analyses of cotton homologs of ArabidopsisPA regulator TRANSPARENT TESTA 2 (TT2) and fine‐mapping of the cotton dark‐brown fibre gene (Lc1), we show that a TT2 homolog, GhTT2‐3A, controls PA biosynthesis and brown pigmentation in cotton fibres. We observed that GhTT2‐3A activated GhbHLH130D, a homolog of ArabidopsisTT8, which in turn synergistically acted with GhTT2‐3A to activate downstream PA structural genes and PA synthesis and accumulation in cotton fibres. Furthermore, the up‐regulation of GhTT2‐3A in fibres at the secondary wall‐thickening stage resulted in brown mature fibres, and fibre quality and lint percentage were comparable to that of the white‐fibre control. The findings of this study reveal the regulatory mechanism controlling brown pigmentation in cotton fibres and demonstrate a promising biotechnological strategy to break the negative linkage between coloration and fibre quality and/or productivity.     

Interaction and developmental activation of two neuroendocrine systems that regulate light‐mediated skin pigmentation

Lower vertebrates use rapid light‐regulated changes in skin colour for camouflage (background adaptation) or during circadian variation in irradiance levels. Two neuroendocrine systems, the eye/alpha‐melanocyte‐stimulating hormone (α‐MSH) and the pineal complex/melatonin circuits, regulate the process through their respective dispersion and aggregation of pigment granules (melanosomes) in skin melanophores. During development, Xenopus laevis tadpoles raised on a black background or in the dark perceive less light sensed by the eye and darken in response to increased α‐MSH secretion. As embryogenesis proceeds, the pineal complex/melatonin circuit becomes the dominant regulator in the dark and induces lightening of the skin of larvae. The eye/α‐MSH circuit continues to mediate darkening of embryos on a black background, but we propose the circuit is shut down in complete darkness in part by melatonin acting on receptors expressed by pituitary cells to inhibit the expression of pomc, the precursor of α‐MSH.     

Waist Circumference,BMI, and Visceral Adipose Tissue in White Women and Women of African Descent

Although waist circumference (WC) is a marker of visceral adipose tissue (VAT), WC cut‐points are based on BMI category. We compared WC‐BMI and WC‐VAT relationships in blacks and whites. Combining data from five studies, BMI and WC were measured in 1,409 premenopausal women (148 white South Africans, 607 African‐Americans, 186 black South Africans, 445 West Africans, 23 black Africans living in United States). In three of five studies, participants had VAT measured by computerized tomography (n = 456). Compared to whites, blacks had higher BMI (29.6 ± 7.6 (mean ± s.d.) vs. 27.6 ± 6.6 kg/m², P = 0.001), similar WC (92 ± 16 vs. 90 ± 15 cm, P = 0.27) and lower VAT (64 ± 42 vs. 101 ± 59 cm², P < 0.001). The WC‐BMI relationship did not differ by race (blacks: β (s.e.) WC = 0.42 (.01), whites: β (s.e.) WC = 0.40 (0.01), P = 0.73). The WC‐VAT relationship was different in blacks and whites (blacks: β (s.e.) WC = 1.38 (0.11), whites: β (s.e.) WC = 3.18 (0.21), P < 0.001). Whites had a greater increase in VAT per unit increase in WC. WC‐BMI and WC‐VAT relationships did not differ among black populations. As WC‐BMI relationship did not differ by race, the same BMI‐based WC guidelines may be appropriate for black and white women. However, if WC is defined by VAT, race‐specific WC thresholds are required.     

Trace fossils of the Jurassic,blue Lias,Lyme Regis,Southern England

The Lower Jurassic, Blue Lias Formation at Lyme Regis, Dorset, England is rhythmically bedded with symmetrical rhythms consisting of laminated black shale followed by dark then pale marls (sometimes cemented into pale limestones) and back to laminated black shale. Its trace fossil fauna includes nine ichno‐genera and represents a shallow shelf paleoenviron‐ment. The ichnofauna occurs in three assemblages named after consistently occurring ichnogenera. A Chondrites assemblage (diversity = 1 ichnogenus) and a Chondrites‐Arenicolites assemblage (diversity = 2–3 ichnogenera) are typical of dark marls but may penetrate tops of laminated black shales. A thalassi‐noides‐Chondrites‐Arenicolites assemblage (diversity up to 7 ichnogenera) is typical of pale marls or limestones. Blue Lias limestones are diagenetic: dark laminated limestones and pale bioturbated limestones are cemented equivalents of laminated black shales and pale marls, respectively. However, pale burrow fills in darker sediments and vice versa confirm the rhythms are primary. Rhythms represent redox cycles, fluctuating from anoxic laminated black shales lacking mac‐robenthos or infauna (bioturbation index = 0) to oxic, bioturbated, pale marls or limestones with large mac‐robenthos such as Gryphaea or Plagiostoma and diverse infauna (bioturbation index = 5).     

Postharvest Fruit rot of Persimmon (Diospyros kaki) in Spain Caused by Lasiodiplodia theobromae and Neofusicoccum spp.

Three different fungi (isolates IVIA QCV‐1, IVIA QCV‐3 and IVIA QCV‐4) were isolated as potential causal agents of postharvest decay losses observed on sweet persimmons (Diospyros kaki L.) cv. ‘Rojo Brillante’ from commercial packinghouses in the Valencia area (Spain). Disease symptoms were irregular brownish and soft lesions mainly located under and surrounding the fruit calyx (stem‐end) that expanded rapidly at room temperature and turned to dark brown or black colour producing apparent and in some cases abundant white to grey mycelium. The identification of Lasiodiplodia theobromae, Neofusicoccum mediterraneum and Neofusicoccum luteum by macroscopic and microscopic morphological observations was confirmed with the amplification and subsequent sequencing of the ribosomal DNA ITS2 region. Representative nucleotide sequences were deposited in GenBank. Pathogenicity of all three isolates was demonstrated by fulfilling Koch's postulates.     

Yield,development, and quality response of dual‐toxin Bt cotton to Helicoverpa spp. infestations in Australia

To verify current thresholds for Bollgard II^® cotton in Australia, the impact of Helicoverpa spp. (Lepidoptera: Noctuidae) larvae on yield, development, and quality under various infestation intensities and durations, and stages of growth, was tested using small plot field experiments over two seasons. Infestation with up to 80 eggs m^?1 of Helicoverpa armigera (Hübner) and Helicoverpa punctigera Wallengren showed that species, infestation level, and stage of growth had no significant effect on yields of seed‐cotton or lint and on maturity and fibre quality. The duration of infestation of white flowers with H. punctigera neonates (maximum of every day for up to 4 weeks) had no impact on the yield of seed‐cotton or lint, maturity, and fibre quality, but when 100% of flowers were infested (compared with 0 or 50%), seed‐cotton and lint yields were significantly reduced and maturity was delayed. Infestation with up to 18 medium H. armigera larvae m^?1 at several plant stages did not significantly affect yields of seed‐cotton and lint, maturity, and fibre quality. A heliocide spray applied on a commercial farm at the current threshold resulted in a significantly higher lint yield, compared with a farm where no spray was applied. In conclusion, Bollgard II^® cotton is highly resistant to Helicoverpa spp. infestation.     

Mating behavior and rapid concealing of nuptial coloration in males of the Fishgod Blenny <Emphasis Type="Italic">Malacoctenus ebisui</Emphasis> (Teleostei: Blenniiformes)

Courting males often face the trade-off of attracting the attention of both females and predators. Rapid color change, a relatively simple solution to this dilemma, is described for nuptial males of the Fishgod Blenny Malacoctenus ebisui (Teleostei: Blenniiformes) from direct observations at three rocky reefs in the Mexican Pacific. Nuptial males showed three dark bars on a white background that covered the anterior part of the body, and three dark bars posteriorly forming a solid dark patch along the midline. The head was black with a prominent white area on the lower portion of the iris of each eye, two white patches on the upper jaw, and one central white patch on the lower jaw. When an intensely colored male was disturbed the white patches on the eyes quickly disappeared, while the other white markings became muted apparently by rapid expansion of melanophores. This relatively simple system permits males of the Fishgod Blenny to rapidly suppress their conspicuous coloration in response to perceived threats. Mating behavior of the Fishgod Blenny observed at Bahia Chamela is similar to that reported for other labrisomid blennies, with males repeatedly nudging the side of the female and both sexes alternately performing quivering movements.     

Changes in cardiovascular disease risk factors from age 9 to 19 and the influence of television viewing

Objective:

The purpose of this study was to determine if time spent watching television is associated with changes in cardiovascular disease (CVD) risk factors from age 9 to 19.

Design and Methods:

Participants were girls enrolled in the NHLBI Growth and Health Study (n = 1,702), and CVD risk factors were measured at ages 10, 12, 14, 16, and 19. Longitudinal quantile regression was used to determine if television viewing was associated with changes in CVD risk factors over time at the 10th, 25th, 50th, 75th, and 90th percentiles of the CVD risk factors.

Results:

In black girls, television viewing (h/wk) was positively associated with sum of skinfolds (mm) at the 75th (0.22, 99% CI, 0.06‐0.38) and 90th percentiles (0.21, 99% CI, 0.05‐0.36), but not at the 10th, 25th, or 50th percentiles. In white girls, television viewing (h/wk) was positively associated with sum of skinfolds (mm) with the strength of the associations progressively stronger toward the upper tail of the skinfold distribution, adjusting for physical activity and other covariates (10th percentile: 0.08, 99% CI, 0.03‐0.13; 90th percentile: 0.42, 99% CI, 0.24‐0.59). All associations were adjusted for physical activity, dietary factors, sleep, and maturation. No associations were observed between television viewing and changes in systolic blood pressure, triglycerides, or cholesterol levels in black or white girls.

Conclusion:

Girls who spent more time watching television had greater increases in sum of skinfolds from age 9 to 19, independent of physical activity levels and other covariates. The associations observed were stronger at the upper tail of the skinfold distribution.     

Juvenile white sturgeon (Acipenser transmontanus) habitat and distribution in the Lower Fraser River, downstream of Hope, BC, Canada

The primary objective of this study was to identify and characterize juvenile white sturgeon (Acipenser transmontanus) habitat in the Lower Fraser River downstream of Hope, BC, Canada. A secondary objective was to estimate the juvenile white sturgeon population in the Lower Fraser River. A total of 1867 white sturgeon was captured with gill nets at 26 sites in the Lower Fraser River. The greatest numbers of sturgeon were caught in three sloughs; all but three sturgeon were captured in the June to August period. These three sloughs all had water deeper than 5 m and current that was multidirectional. Turbidity ranged greatly from 1.5 NTU (Nephelometric Units) to 67.0 NTU and the substrate of most sites was fine sediments, fine sand, silt and clay. Stomach contents were mysid shrimp (Mysidacea), midge larvae (Chironomidae) and peamouth chub (Mylocheilus caurinus). We identified three of 26 sites with appreciable numbers of juvenile sturgeon, identified water quality parameters of these sites, identified any incidental species that might be prey and also determined that between 1985 and 1993 the juvenile white sturgeon population had declined.     

Racial and ethnic differences in secular trends for childhood BMI, weight, and height

Objectives: The prevalence of childhood overweight in the United States has markedly increased over the last 30 years. We examined differences in the secular trends for BMI, weight, and height among white, black, and Mexican‐American children. Research Methods and Procedures: Analyses were based on nationally representative data collected from 2 to 17 year olds in four examinations (1971–1974 through 1999–2002). Results: Overall, black children experienced much larger secular increases in BMI, weight, and height than did white children. For example, over the 30‐year period, the prevalence of overweight increased ～3‐fold (4% to 13%) among 6‐ to 11‐year‐old white children but 5‐fold (4% to 20%) among black children. In most sex‐age groups, Mexican‐American children experienced increases in BMI and overweight that were between those experienced by blacks and whites. Race/ethnicity differences were less marked among 2 to 5 year olds, and in this age group, white children experienced the largest increase in overweight (from 4% to 9%). In 1999–2002, the prevalence of extreme BMI levels (≥99th percentile) reached 6% to 7% among black girls and Mexican‐American boys. Discussion: Because of the strong tracking of childhood BMI levels into adulthood, it is likely that the secular increases in childhood overweight will greatly increase the burden of adult disease. The further development of obesity interventions in different racial/ethnic groups should be emphasized.     

Mineral concentrations in serum/plasma and liver tissue of captive and free‐ranging Rhinoceros species

Mineral implications in health issues of captive rhinos have received much attention lately. This study was undertaken to establish reference values for the mineral status of rhinos. Serum/plasma samples of free‐ranging black (Diceros bicornis) and white (Ceratotherium simum) rhinos and of captive black, white, Indian (Rhinoceros unicornis), and Sumatran (Dicerorhinus sumatrensis) rhinos, as well as liver tissue samples of captive black, white, and Indian rhinos were analyzed for mineral content. Circulating mineral levels of free‐ranging animals were subject to variation according to region. In free‐ranging animals, high molybdenum (Mo) values compared to horse normals were striking. Captive animals displayed even higher circulating Mo concentrations. The significance of iron (Fe) overload in captive specimens of the browsing rhinos (black and Sumatran) was confirmed. Hepatic Fe levels increased in blacks with age. Although this Fe overload is suspected to be linked with diets, the data indicate that this is not due solely to an excessive dietary Fe supply. Whereas the grazing species (white and Indian) had high liver copper (Cu) levels, the browsing species had low to marginal liver Cu concentrations. Liver concentrations of K, Mg, Co, and Mo increased with age in captive black rhinos. Additional findings include high circulating Se levels in all rhino species. Future research should be directed at investigating factors leading to high Fe levels, and at investigating Cu metabolism in captive rhinoceros species. Zoo Biol 24:51–72, 2005. © 2005 Wiley‐Liss, Inc.     

Effect of Glycemic Load on Peptide‐YY Levels in a Biracial Sample of Obese and Normal Weight Women

Black women suffer a disproportionately higher rate of obesity than their white counterparts. Reasons for this racial disparity may reflect underlying differences in the appetite suppressing peptide‐YY (PYY). The PYY response to food is differentially influenced by macronutrient content but the effect of glycemic load on PYY response is unknown. This study examined whether glycemic load influences fasting and postprandial PYY levels and whether fasting and postprandial PYY levels are lower in obese black women compared to normal weight black women and to white women. Data were collected from 40 women (20 black, 20 white; 10 each normal weight vs. obese) at the University of North Carolina Clinical and Translational Research Center (CTRC). Participants completed in counterbalanced order two 4½‐day weight‐maintenance, mixed macronutrient high vs. low glycemic load diets followed by a test meal of identical composition. Total PYY levels were assessed before and after each test meal. Results show no differences in fasting PYY levels but significantly less postprandial PYY area under the curve (PYY_AUC) in the group of obese black women compared to each other group (race × obesity interaction, P < 0.04). PYY_AUC was positively related to insulin sensitivity (P < 0.004) but was not affected by glycemic load (main and interactive effects, P > 0.27). These findings indicate that postprandial PYY secretion is not affected by glycemic load but is blunted in obese black women compared with normal weight black women and with white women; additionally, they begin to address whether blunted PYY secretion contributes uniquely to the pathogenesis of obesity in black women.