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Annual Review of Genetics Nov 2023Vertebrates exhibit a wide range of color patterns, which play critical roles in mediating intra- and interspecific communication. Because of their diversity and visual... (Review)
Review
Vertebrates exhibit a wide range of color patterns, which play critical roles in mediating intra- and interspecific communication. Because of their diversity and visual accessibility, color patterns offer a unique and fascinating window into the processes underlying biological organization. In this review, we focus on describing many of the general principles governing the formation and evolution of color patterns in different vertebrate groups. We characterize the types of patterns, review the molecular and developmental mechanisms by which they originate, and discuss their role in constraining or facilitating evolutionary change. Lastly, we outline outstanding questions in the field and discuss different approaches that can be used to address them. Overall, we provide a unifying conceptual framework among vertebrate systems that may guide research into naturally evolved mechanisms underlying color pattern formation and evolution.
Topics: Animals; Biological Evolution; Pigmentation; Vertebrates
PubMed: 37487589
DOI: 10.1146/annurev-genet-031423-120918 -
Revista Clinica Espanola May 2024Identify and reach consensus on the variables that affect the measurement of oxygen saturation using pulse oximetry. (Review)
Review
OBJECTIVE
Identify and reach consensus on the variables that affect the measurement of oxygen saturation using pulse oximetry.
METHODS
We applied inclusion and exclusion criteria to select relevant studies in databases such as Ebsco and PubMed. The search strategies, carried out until December 2023, focused on publications that addressed the technology of pulse oximeters and variables that influence their accuracy. We assessed the risk of bias of the included studies and used standardized methods for synthesis of results.
RESULTS
23 studies were included. The synthesis of the results highlighted that equipment with tetrapolar technology showed greater precision in oxygen saturation measurements. Increased skin pigmentation, hemoglobinopathies and high skin temperatures can lead to an overestimation of SpO, while factors such as low perfusion, cold skin temperature, nail polish or tattoos, hypoxemia, anemia and high altitude training, they may underestimate it. On the other hand, motion artifacts, light pollution, frequency >150 beats per minute, electromagnetic interference and location of the sensor can cause distortion of the photoplethymography signal.
CONCLUSIONS
The synthesis of the results highlighted that skin pigmentation and light interference can lead to an overestimation of SpO, while other factors such as low perfusion and altitude tend to underestimate it. The studies presented variability and heterogeneity in their designs, evidencing limitations in the consistency and precision of the evidence. Despite these limitations, the results underscore the importance of considering multiple variables when interpreting pulse oximetry measurements to ensure their reliability. The findings have significant implications for clinical practice and future research.
Topics: Oximetry; Humans; Oxygen Saturation; Reproducibility of Results; Skin Pigmentation
PubMed: 38599519
DOI: 10.1016/j.rceng.2024.04.005 -
Annual International Conference of the... Jul 2023Remote photoplethysmography (rPPG) is an attractive method for noninvasive, convenient and concomitant measurement of physiological vital signals. Public benchmark...
Remote photoplethysmography (rPPG) is an attractive method for noninvasive, convenient and concomitant measurement of physiological vital signals. Public benchmark datasets have served a valuable role in the development of this technology and improvements in accuracy over recent years. However, there remain gaps in the public datasets. First, despite the ubiquity of cameras on mobile devices, there are few datasets recorded specifically with mobile phone cameras. Second, most datasets are relatively small and therefore are limited in diversity, both in appearance (e.g., skin tone), behaviors (e.g., motion) and environment (e.g., lighting conditions). In an effort to help the field advance, we present the Multi-domain Mobile Video Physiology Dataset (MMPD), comprising 11 hours of recordings from mobile phones of 33 subjects. The dataset is designed to capture videos with greater representation across skin tone, body motion, and lighting conditions. MMPD is comprehensive with eight descriptive labels and can be used in conjunction with the rPPG-toolbox [1]. The reliability of the dataset is verified by mainstream unsupervised methods and neural methods. The GitHub repository of our dataset: https://github.com/THU-CS-PI/MMPD_rPPG_dataset.
Topics: Humans; Algorithms; Reproducibility of Results; Skin; Photoplethysmography; Skin Pigmentation
PubMed: 38083085
DOI: 10.1109/EMBC40787.2023.10340857 -
Nature Genetics Feb 2024Skin color is highly variable in Africans, yet little is known about the underlying molecular mechanism. Here we applied massively parallel reporter assays to screen...
Skin color is highly variable in Africans, yet little is known about the underlying molecular mechanism. Here we applied massively parallel reporter assays to screen 1,157 candidate variants influencing skin pigmentation in Africans and identified 165 single-nucleotide polymorphisms showing differential regulatory activities between alleles. We combine Hi-C, genome editing and melanin assays to identify regulatory elements for MFSD12, HMG20B, OCA2, MITF, LEF1, TRPS1, BLOC1S6 and CYB561A3 that impact melanin levels in vitro and modulate human skin color. We found that independent mutations in an OCA2 enhancer contribute to the evolution of human skin color diversity and detect signals of local adaptation at enhancers of MITF, LEF1 and TRPS1, which may contribute to the light skin color of Khoesan-speaking populations from Southern Africa. Additionally, we identified CYB561A3 as a novel pigmentation regulator that impacts genes involved in oxidative phosphorylation and melanogenesis. These results provide insights into the mechanisms underlying human skin color diversity and adaptive evolution.
Topics: Humans; Skin Pigmentation; Melanins; Alleles; Genomics; Pigmentation; Polymorphism, Single Nucleotide; Repressor Proteins; Albinism, Oculocutaneous
PubMed: 38200130
DOI: 10.1038/s41588-023-01626-1 -
Cell Reports Aug 2023Hanly et al. and Nishida et al. use distinct approaches to provide exceptional lessons regarding the genetic, molecular, morphological, and biochemical bases of...
Hanly et al. and Nishida et al. use distinct approaches to provide exceptional lessons regarding the genetic, molecular, morphological, and biochemical bases of butterfly wing pigmentation. These mechanistic insights collectively have important implications for our understanding of phenotype evolution.
Topics: Animals; Butterflies; Pigmentation; Phenotype
PubMed: 37594895
DOI: 10.1016/j.celrep.2023.112981 -
Plant, Cell & Environment Dec 2023For many fruit crops, the colour of the fruit outwardly defines its eating quality. Fruit pigments provide reproductive advantage for the plant as well as providing... (Review)
Review
For many fruit crops, the colour of the fruit outwardly defines its eating quality. Fruit pigments provide reproductive advantage for the plant as well as providing protection against unfavourable environmental conditions and pathogens. For consumers these colours are considered attractive and provide many of the dietary benefits derived from fruits. In the majority of species, the main pigments are either carotenoids and/or anthocyanins. They are produced in the fruit as part of the ripening process, orchestrated by phytohormones and an ensuing transcriptional cascade, culminating in pigment biosynthesis. Whilst this is a controlled developmental process, the production of pigments is also attuned to environmental conditions such as light quantity and quality, availability of water and ambient temperature. If these factors intensify to stress levels, fruit tissues respond by increasing (or ceasing) pigment production. In many cases, if the stress is not severe, this can have a positive outcome for fruit quality. Here, we focus on the principal environmental factors (light, temperature and water) that can influence fruit colour.
Topics: Fruit; Anthocyanins; Carotenoids; Pigmentation; Water; Gene Expression Regulation, Plant; Plant Proteins
PubMed: 37555620
DOI: 10.1111/pce.14684 -
Pigment Cell & Melanoma Research Sep 2023The epigenetic repressor BMI1 plays an integral role in promoting the self-renewal and proliferation of many adult stem cell populations, and also tumor types, primarily...
The epigenetic repressor BMI1 plays an integral role in promoting the self-renewal and proliferation of many adult stem cell populations, and also tumor types, primarily through silencing the Cdkn2a locus, which encodes the tumor suppressors p16 and p19 . However, in cutaneous melanoma, BMI1 drives epithelial-mesenchymal transition programs, and thus metastasis, while having little impact on proliferation or primary tumor growth. This raised questions about the requirement and role for BMI1 in melanocyte stem cell (McSC) biology. Here, we demonstrate that murine melanocyte-specific Bmi1 deletion causes premature hair greying and gradual loss of melanocyte lineage cells. Depilation enhances this hair greying defect, accelerating depletion of McSCs in early hair cycles, suggesting that BMI1 acts to protect McSCs against stress. RNA-seq of McSCs, harvested before onset of detectable phenotypic defects, revealed that Bmi1 deletion derepresses p16 and p19 , as observed in many other stem cell contexts. Additionally, BMI1 loss downregulated the glutathione S-transferase enzymes, Gsta1 and Gsta2, which can suppress oxidative stress. Accordingly, treatment with the antioxidant N-acetyl cysteine (NAC) partially rescued melanocyte expansion. Together, our data establish a critical function for BMI1 in McSC maintenance that reflects a partial role for suppression of oxidative stress, and likely transcriptional repression of Cdkn2a.
Topics: Mice; Animals; Cyclin-Dependent Kinase Inhibitor p16; Melanoma; Proto-Oncogene Proteins; Skin Neoplasms; Stem Cells; Polycomb Repressive Complex 1; Pigmentation; Melanocytes; Hair
PubMed: 37132544
DOI: 10.1111/pcmr.13088 -
Biology Letters Aug 2023Disruptive markings are common in animal patterns and can provide camouflage benefits by concealing the body's true edges and/or by breaking the surface of the body into...
Disruptive markings are common in animal patterns and can provide camouflage benefits by concealing the body's true edges and/or by breaking the surface of the body into multiple depth planes. Disruptive patterns that are accentuated by high contrast borders are most likely to provide false depth cues to enhance camouflage, but studies to date have used visual detection models or humans as predators. We presented three-dimensional-printed moth-like targets to wild bird predators to determine whether: (1) three-dimensional prey with disrupted body surfaces have higher survival than three-dimensional prey with continuous surfaces, (2) two-dimensional prey with disruptive patterns or enhanced edge markings have higher survival than non-patterned two-dimensional prey. We found a survival benefit for three-dimensional prey with disrupted surfaces, and a significant effect of mean wing luminance. There was no evidence that false depth cues provided the same protective benefits as physical surface disruption in three-dimensional prey, perhaps because our treatments did not mimic the complexity of patterns found in natural animal markings. Our findings indicate that disruption of surface continuity is an important strategy for concealing a three-dimensional body shape.
Topics: Humans; Animals; Pigmentation; Predatory Behavior; Birds; Moths; Cues
PubMed: 37528728
DOI: 10.1098/rsbl.2022.0596 -
Experimental Cell Research Jan 2024The voltage-dependent anion channel 1 (VDAC1) forms an oligomeric structure on the mitochondrial outer membrane, which plays critical roles in many physiological...
The voltage-dependent anion channel 1 (VDAC1) forms an oligomeric structure on the mitochondrial outer membrane, which plays critical roles in many physiological processes. Research studies have demonstrated that the knockout of VDAC1 increases pigment content and up-regulates the expression of melanogenic genes. Due to its involvement in various physiological processes, the depletion of VDAC1 has significant detrimental effects on cellular functions and the inhibition of VDAC1 oligomerization has recently emerged as a promising strategy for the treatment of several diseases. In this study, we found that VDAC1 oligomerization inhibitors, VBIT-12 and NSC-15364, promote melanogenesis, dendrite formation and melanosome transport in human epidermal melanocytes (HEMCs). Mechanistically, treatment of HEMCs with an oligomerization inhibitor increased the level of cytoplasmic calcium ions, which activated calcium-calmodulin dependent protein kinase (CaMK) and led to the phosphorylation of CREB and the nuclear translocation of CREB-regulated transcription coactivators (CRTCs). Subsequently, CRTCs, p-CREB and CREB-binding protein (CBP) in the nucleus cooperatively recruit the transcription machinery to initiate the transcription of MITF thus promoting pigmentation. Importantly, our study also demonstrates that VDAC1 oligomerization inhibitors increase pigmentation in zebrafish and in human skin explants, highlighting their potential as a therapeutic strategy for skin pigmentation disorders.
Topics: Animals; Humans; Pigmentation Disorders; Voltage-Dependent Anion Channel 1; Calcium; Zebrafish; Melanocytes; Melanins; Pigmentation; Microphthalmia-Associated Transcription Factor
PubMed: 38070860
DOI: 10.1016/j.yexcr.2023.113874 -
Journal of Translational Medicine Apr 2024Melanocytes are dendritic cells localized in skin, eyes, hair follicles, ears, heart and central nervous system. They are characterized by the presence of melanosomes... (Review)
Review
Melanocytes are dendritic cells localized in skin, eyes, hair follicles, ears, heart and central nervous system. They are characterized by the presence of melanosomes enriched in melanin which are responsible for skin, eye and hair pigmentation. They also have different functions in photoprotection, immunity and sound perception. Melanocyte dysfunction can cause pigmentary disorders, hearing and vision impairments or increased cancer susceptibility. This review focuses on the role of melanocytes in homeostasis and disease, before discussing their potential in regenerative medicine applications, such as for disease modeling, drug testing or therapy development using stem cell technologies, tissue engineering and extracellular vesicles.
Topics: Regenerative Medicine; Melanocytes; Pigmentation; Melanins; Hair Follicle
PubMed: 38589876
DOI: 10.1186/s12967-024-05113-x