Artificial selection for structural color on butterfly wings and comparison with natural evolution

Brilliant animal colors often are produced from light interacting with intricate nano-morphologies present in biological materials such as butterfly wing scales. Surveys across widely divergent butterfly species have identified multiple mechanisms of structural color production; however, little is known about how these colors evolved. Here, we examine how closely related species and populations of Bicyclus butterflies have evolved violet structural color from brown-pigmented ancestors with UV structural color. We used artificial selection on a laboratory model butterfly, B. anynana, to evolve violet scales from UV brown scales and compared the mechanism of violet color production with that of two other Bicyclus species, Bicyclus sambulos and Bicyclus medontias, which have evolved violet/blue scales independently via natural selection. The UV reflectance peak of B. anynana brown scales shifted to violet over six generations of artificial selection (i.e., in less than 1 y) as the result of an increase in the thickness of the lower lamina in ground scales. Similar scale structures and the same mechanism for producing violet/blue structural colors were found in the other Bicyclus species. This work shows that populations harbor large amounts of standing genetic variation that can lead to rapid evolution of scales’ structural color via slight modifications to the scales’ physical dimensions.Organisms produce colors in two basic ways: by synthesizing pigments that selectively absorb light of certain spectral bands so that only light outside the absorption bands is backscattered (chemical color) or by developing nanomorphologies that enhance the reflection of light of certain wavelengths by interference (physical color or structural color). Structural colors play major roles in natural and sexual selection in many species (1) and have a broad range of applications in color display, paint, cosmetics, and textile industries (2). Structural color surveys across widely divergent species have revealed a large diversity of color-producing mechanisms (3–9). However, there has been a lack of systematic study and comparison of how different colors from closely related species or within populations of a single species evolve, even though these colors can vary dramatically. By examining how these species/populations evolve different colors, it is possible to identify the minimal amount of morphological change that results in significant color variation. Furthermore, this research may serve as an inspiration for future application of similar evolutionary principles to the design of photonic devices for color tuning, light trapping, or beam steering (2, 10–20). From an evolutionary biology point of view, we are curious to examine how structural colors respond to selection pressure and whether there is sufficient standing genetic variation in natural populations to allow the rapid evolution of novel colors. Here we focus on determining the morphological changes and the physical mechanisms that cause the evolution of violet structural color in populations of a single species and also across different species within a single genus of butterflies.We focus on the genus Bicyclus (Lepidoptera: Nymphalidae), composed of more than 80 species that predominantly exhibit brown color along with marginal eyespots. Some Bicyclus species, however, have independently evolved transverse bands of bright violet/blue structural color on the dorsal surface of the forewings (black asterisks in Fig. 1A) (21, 22). One species, Bicyclus anynana, has become a model species amenable to laboratory rearing, and multiple aspects of its marginal eyespots (size, relative width of the color rings, shape) have been altered by artificial selection (23–27). However, change of color (hue), either pigmentary or structural, via artificial selection has not been reported. B. anynana does not exhibit bright violet coloration on its wings and therefore provides an excellent opportunity for investigating whether there is genetic potential to produce violet color upon directed selection. We investigated this potential by performing an artificial selection experiment in B. anynana that targeted the color of the specific dorsal wing region that evolved violet/blue coloration in other members of the genus (Fig. 1 B–G).Open in a separate windowFig. 1.Structural color in Bicyclus butterflies and basic wing scale morphology. (A) A phylogenetic estimate of Bicyclus butterfly relationships (modified from ref. 41) illustrating the evolution of color in the genus. The black asterisks mark two clades that evolved violet/blue color independently, represented here by B. sambulos and B. medontias. (B–D) Dorsal wing images of B. sambulos, B. anynana (the region used for artificial selection is marked by white asterisk), and B. medontias. (E–G) Graphs of reflectance spectra of the blue/violet wing band showing reflectance peaks in the 400–450 nm range and in the brown-colored homologous region in B. anynana with a UV reflectance peak centered at 300 nm (colored arrows). (H) 3D illustration of the wing and scales in the selected wing area of B. anynana. (I) Magnified view of the ripped region in H showing how cover (c; brown) and ground (g; green) scales are attached to the wing membrane (m, pink) and alternate along rows. Scales on the other (ventral) side of the wing membrane are visible also. (J) Cross-sectional view of a single scale showing the trabeculae (T) connecting the lower lamina (LL) to the upper lamina that includes ridges (R), microribs (Mr), and crossribs (Cr). Windows (W) are the spaces between the ridges and crossribs. Cover and ground scales have the same basic morphology. [llustrations in H–J courtesy of Katerina Evangelou (Central Saint Martin’s College, London).]B. anynana, like other butterflies, has two types of scales, cover and ground, which alternate within a row with cover scales partially covering the ground scales and the point where both scales attach to the wing membrane (Fig. 1 H and I and Fig. S1) (28). Both cover and ground scales contain a lower lamina with a continuous smooth surface below a region composed of longitudinal ridges and crossribs, collectively referred to as the “upper lamina” and connected to the lower lamina via pillars called “trabeculae” (Fig. 1J and Fig. S1) (6). Previous studies on butterflies showed that structural color can be produced by interference with light reflected from the overlapping lamella that build the longitudinal ridges, from microribs protruding from the sides of the longitudinal ridges, or from the lower lamina, which can vary in thickness and patterning (Fig. 1J) (29, 30). However, it is not clear how the violet/blue color is produced in members of the two Bicyclus clades that separately evolved this color, whether B. anynana can be made to evolve the same violet/blue color via artificial selection, and whether it will generate the color in the same way as the other species. To answer these questions, we conducted detailed optical characterization and structural analysis of butterfly wing scales from three separate species and artificially evolved populations of Bicyclus to illustrate how color is generated and how it has evolved.     

Corrigendum

Introduction

In the mid-1990s, Cambodia faced one of the fastest growing HIV epidemics in Asia. For its achievement in reversing this trend, and achieving universal access to HIV treatment, the country received a United Nations millennium development goal award in 2010. This article reviews Cambodia’s response to HIV over the past two decades and discusses its current efforts towards elimination of new HIV infections.

Methods

A literature review of published and unpublished documents, including programme data and presentations, was conducted.

Results and discussion

Cambodia classifies its response to one of the most serious HIV epidemics in Asia into three phases. In Phase I (1991–2000), when adult HIV prevalence peaked at 1.7% and incidence exceeded 20,000 cases, a nationwide HIV prevention programme targeted brothel-based sex work. Voluntary confidential counselling and testing and home-based care were introduced, and peer support groups of people living with HIV emerged. Phase II (2001–2011) observed a steady decline in adult prevalence to 0.8% and incidence to 1600 cases by 2011, and was characterized by: expanding antiretroviral treatment (coverage reaching more than 80%) and continuum of care; linking with tuberculosis and maternal and child health services; accelerated prevention among key populations, including entertainment establishment-based sex workers, men having sex with men, transgender persons, and people who inject drugs; engagement of health workers to deliver quality services; and strengthening health service delivery systems. The third phase (2012–2020) aims to attain zero new infections by 2020 through: sharpening responses to key populations at higher risk; maximizing access to community and facility-based testing and retention in prevention and care; and accelerating the transition from vertical approaches to linked/integrated approaches.

Conclusions

Cambodia has tailored its prevention strategy to its own epidemic, established systematic linkages across different services and communities, and achieved nearly universal coverage of HIV services nationwide. Still, the programme must continually (re)prioritize the most effective and efficient interventions, strengthen synergies between programmes, contribute to health system strengthening, and increase domestic funding so that the gains of the previous two decades are sustained, and the goal of zero new infections is reached.     

Ciliated muconodular papillary tumor of the lung: A newly defined peripheral pulmonary tumor with conspicuous mucin pool mimicking colloid adenocarcinoma: A case report and review of literature

We report the case of a 68‐year‐old man with a newly defined rare entity of a peripheral pulmonary tumor, consisting of a nodular papillary lesion with papillary structures containing ciliated columnar and goblet cells, as well as floating tumor cells in the mucin pool. The conspicuous mucin pool was observed to be mimicking colloid adenocarcinoma in a low‐power view, particularly in a frozen section slide. We originally reported it as an adenocarcinoma during intraoperative consultation. Immunohistochemically, the tumor cells exhibited a similar immunophenotype to pulmonary adenocarcinoma, except for the presence of focal ciliated and basaloid cells, which we found using CK5/6 and P63 immunostaining. No KRAS or EGFR mutation was found. We revised the diagnosis to that of a ciliated muconodular papillary tumor (CMPT). Four years after a wedge resection, the patient remained free of tumors. Although the malignant potential of CMPT cannot be ignored, a wedge resection with a safe margin might be a treatment option for CMPT patients.     

Gastric metastasis of hepatocellular carcinoma via a possible existing retrograde hematogenous pathway

Background and Aim: Hepatocellular carcinoma (HCC) tends to metastasize to extrahepatic organs. Stomach involvement has been seldom reported and has always been considered as direct invasion. This study aims to propose a possible existing pathway for the hematogenous metastasis of HCC to the stomach. Methods: Only seven cases with stomach involvement were found from 8267 HCC patients registered at our hospital between 2000 and 2007. Their laboratory data, the findings of computed tomography and upper endoscopy, therapeutic procedures, such as esophageal variceal banding ligation (EVL), and transhepatic arterial embolization (TAE) were further studied. Results: All seven patients were male. Liver cirrhosis was found in six patients (6/7 = 85.7%), HCC with portal vein thrombosis (PVT) in six patients (6/7 = 85.7%), splenomegaly in five patients (5/7 = 71.4%) and esophageal varices in five patients (5/7 = 71.4%). Six patients underwent TAE and one patient underwent EVL before the development of HCC in the stomach. Four patients had HCC at the cardia, one patient at the anterior wall of the high body and two patients at the greater curvature of the high body, far away from the original HCC. Six patients eventually developed distant metastasis. HCC with gastric metastasis developed 53–126 days after TAE in five patients and 74 days after EVL in one patient. Conclusions: When cirrhotic patients with portal hypertension have HCC with PVT, a hematogenous pathway can exist for gastric metastasis of tumor thrombi involving hepatofugal flow to the stomach after TAE or EVL apart from the major pathway of direct invasion.     

Risk factors associated with having psoriatic arthritis in patients with cutaneous psoriasis

The aim of this study was to determine if the following characteristics were associated with the presence of psoriatic arthritis in a sample of psoriasis patients: race, family history of psoriasis and psoriatic arthritis, age of onset of psoriasis, smoking, alcohol consumption and the maximum body surface area (BSA) affected by psoriasis. This was a case–control study involving 400 psoriasis patients who attended the Psoriasis and Photo‐medicine clinic in the National Skin Center of Singapore over a 1‐year period. Cases were psoriasis patients with psoriatic arthritis while controls were psoriasis patients without psoriatic arthritis. The diagnosis of psoriatic arthritis was made by rheumatologists and participants completed a self‐administered standardized questionnaire. The maximum BSA involved was determined from the case notes. Psoriatic arthritis was not significantly associated with sex, race, age of onset of psoriasis, a family history of psoriasis, smoking and alcohol consumption but was significantly associated with a family history of psoriatic arthritis (P < 0.001) and the maximum body surface involved (P = 0.05). Using multivariate analysis to control for variables, the presence of psoriatic arthritis was significantly associated with a family history of psoriatic arthritis (odds ratio [OR] = 20.5; 95% confidence interval [CI] = 2.49–169.10) and the maximum BSA involved (OR = 2.52; 95% CI = 1.33–4.75). Indian psoriatic patients were more likely to have psoriatic arthritis compared to the other races. A family history of psoriatic arthritis and a greater maximum body surface involved may be associated with having psoriatic arthritis in this study population of psoriasis patients.     

Cornulin, a marker of late epidermal differentiation, is down-regulated in eczema

Background:  Eczema is a common chronic inflammatory skin disorder which shows strong genetic predisposition. To identify new potential molecular determinants of the disease pathogenesis, we performed a gene expression study in an eczema mouse model. This analysis identified a marked down regulation of the cornulin gene ( CRNN ), a member of the epidermal differentiation complex, in the eczema-like skin. We then investigated CRNN as an eczema candidate gene and studied its polymorphism and the expression in the skin of eczema patients.
Methods:  An eczema-like phenotype was induced in mice by allergen (Der p2) patching. Gene expression analysis was performed with the subtractive suppression hybridization method and validated by real time PCR and the transmission disequilibrium test was used to test for genetic associations in 406 multiplex eczema families.
Results:  Der p 2 patched mice developed a localized eczema and a Th 2 skewed systemic response. Real time PCR analysis confirmed a down regulation of CRNN mRNA in eczema-like skin in the mouse model and in human eczema. The CRNN polymorphism rs941934 was significantly associated with atopic eczema in the genetic analysis ( P  = 0.006), though only as part of an extended haplotype including a known associated variant (2282del4) in the filaggrin gene.
Conclusions:  CRNN mRNA expression is decreased in eczematous skin. Further studies are needed to verify whether the associated cornulin polymorphism contribute to the genetic susceptibility in eczema.     

Incidence,mortality and survival patterns of prostate cancer among residents in Singapore from 1968 to 2002

Background  

From 1968 to 2002, Singapore experienced an almost four-fold increase in prostate cancer incidence. This paper examines the incidence, mortality and survival patterns for prostate cancer among all residents in Singapore from 1968 to 2002.     

内窥镜鼻内视神经管减压治疗重症球后视神经炎

目的 观察内窥镜经鼻内视神经管减压治疗重症球后视神经炎的疗效.方法 回顾分析1995年-2007年经眼科药物治疗16-20d其疗效欠佳转来我科的10例16眼资料(其中4例单眼,6例双眼),仅对视力极差的10例10眼施行减压治疗.结果 对10眼视力无光感-30cm数指减压治疗.术后继续药物治疗16-20d,视力恢复到0.3-0.7.经1-8年观察视力0.5-1.0,眼底视乳头色泽正常,而未手术的6眼,视力无光感-20cm数指,眼底视乳头苍白萎缩,血管细小,呈鲜明对比,疗效迥然不同.结论 经眼科药物治疗16-20d,视力仍无光感-眼前数指,CT,MRI检查,排除颅内病变而球后视神经明显增粗的重症病例,应行减压治疗,可恢复较好的视力.     

Development of a Cervical Cancer Control Intervention Program for Cambodian American Women

Southeast Asian immigrants have lower levels of Pap testing than any other racial/ethnic group in the US, and are particularly unfamiliar with western culture and biomedical concepts of prevention. We completed an ethnographic study (N = 42) focusing on cervical cancer screening among Cambodian American women. We also conducted a community-based survey (N = 413) to examine the generalizability of our qualitative results. This report summarizes the results, and describes how we used our findings to influence the content of a multifaceted intervention program targeting Cambodian immigrants. The following constructs were found to be barriers to cervical cancer control: a traditional orientation to the prevention, causation, and treatment of disease; lack of familiarity with western early detection concepts; low levels of knowledge about cervical cancer; concerns about the Pap testing procedure; and health care access issues. In general, the quantitative results confirmed our ethnographic findings. The intervention program, which is delivered by bicultural outreach workers, includes home visits, presentations at small group meetings, barrier-specific counseling, use of a Khmer-language video, and tailored logistic assistance (e.g., transportation and medical interpretation). Both the video and presentation provide cultural context while simultaneously addressing multiple barriers to screening (e.g., women's fear of surgery and preference for female providers). Outreach workers are trained to counsel women about 10 potential barriers including avoidance of biomedicine, perceptions that gynecologic exams are embarrassing, and lack of English proficiency. Our results reinforce the importance of considering health problems within the context of a population's traditional belief systems and daily routines.     

Labelling of cervival and thoracic spinal neurones following injections of horseradish peroxidase in the leg muscles of rats

Following injection of horseradish peroxidase (HRP) solution in the gastrocnemius muscle or the extensor digitorum longus muscle in neonatal and developing albino rats, some neurones in the cervical enlargement, mid-thoracic region and sacral region were labelled in addition to the region of the spinal cord from where the sciatic nerves emerged. The labelling was most probably the result of diffusion of HRP solution from the site of injection to nearby structures.