Loss Of Pigmentation Research Articles

Preserving visual acuity: a compelling 12-year case study of controlling neovascular age-related macular degeneration

IntroductionIn neovascular age-related macular degeneration (nAMD) trials, anti-VEGF injection frequency decreases after the first year, while outcomes remain primarily related to the number of injections. To the best of our knowledge, there are no reports of maintaining the best corrected visual acuity (BCVA) for more than 7 years in extension studies.ObjectiveTo report a 12-year follow-up of a real-world case of nAMD where BCVA was preserved from declining.Case descriptionA 67-year-old Caucasian female presented to our department in June 2010 due to decreased vision in her left eye (LE) within the preceding months. Examination showed a BCVA of 85 letters (L) in the right eye (RE) and 35 L in the LE. Fundus examination showed drusen in the macula of both eyes. Macular edema, loss of the macular lutein pigment, macular hypo/hyperpigmentation were observed in the LE. A diagnosis of Type 2 choroidal neovascular membrane (CNV) in the LE was established and within two months a Type 1 CNV developed in the RE. She undergone 9 injections of bevacizumab (six) and ranibizumab (three) within the first year of treatment in the LE and seven injections of ranibizumab within the first year in the RE.ResultsThe LE had a mean of 5.2 injections per year, and the RE had a mean of 7.5 injections per year, from 2010 to 2022. RE's BCVA dropped by 8L (85L to 77L) and central retinal thickness (CRT) increased by 16 μm (276 μm to 292 μm) while LE’s BCVA increased by 28L (35L to 63L) and CRT decreased by 369 μm (680 μm to 311 μm), at the twelfth year.ConclusionsAlthough the final visual outcome depends on baseline BCVA and lesion type or size, the number of injections is paramount in preserving BCVA and achieving favorable functional outcomes in nAMD, even after 12 years of treatment.

Transcutaneous Auricular Vagus Nerve Stimulation Alleviates Monobenzone-Induced Vitiligo in Mice.

Vitiligo is a complex skin disorder that involves oxidative stress and inflammatory responses and currently lacks a definitive cure. Transcutaneous auricular vagus nerve stimulation (taVNS) is a noninvasive method for targeting the auricular branch of the vagus nerve and has gained widespread attention for potential intervention in the autonomic nervous system. Although previous research has suggested that vagus nerve stimulation can potentially inhibit inflammatory responses, its specific role and mechanisms in vitiligo treatment remain unknown. This study aimed to explore the therapeutic effects of taVNS in a mouse model of vitiligo induced by monobenzone. Initially, a quantitative assessment of the treatment effects on vitiligo mice was conducted using a scoring system, revealing that taVNS significantly alleviated symptoms, particularly by reducing the depigmented areas. Subsequent immunohistochemical analysis revealed the impact of taVNS treatment on melanocyte granules, mitigating pigment loss in the skin of monobenzone-induced vitiligo mice. Further analysis indicated that taVNS exerted its therapeutic effects through multiple mechanisms, including the regulation of oxidative stress, enhancement of antioxidant capacity, promotion of tyrosine synthesis, and suppression of inflammatory responses. The conclusions of this study not only emphasize the potential value of taVNS in vitiligo therapy, but also lay a foundation for future research into the mechanisms and clinical applications of taVNS.

Sargassum spp. Ethanolic Extract Elicits Toxic Responses and Malformations in Zebrafish (Danio rerio) Embryos.

The amount of Sargassum spp. arriving in the Caribbean Sea has increased steadily in the last few years, producing a profound environmental impact on the ecological dynamics of the coasts of the Yucatan Peninsula. We characterized the toxicological effects of an ethanolic extract of Sargassum spp. on zebrafish (Danio rerio) embryos (ZFEs) in a 96-h static bioassay using T1 (0.01 mg/L), T2 (0.1 mg/L), T3 (1 mg/L), T4 (10 mg/L), T5 (25 mg/L), T6 (50 mg/L), T7 (75 mg/L), T8 (100 mg/L), T9 (200 mg/L), and T10 (400 mg/L). In this extract, we detected 74 compounds by gas chromatography-mass spectrometry (GC-MS), of which hexadecanoic acid methyl ester, and 2-pentanone 4-hydroxy-4-methyl, were the most abundant. In ZFEs, a median lethal concentration of 251 mg/L was estimated. Exposed embryos exhibited extensive morphological changes, including edema in the yolk sac, scoliosis, and loss of pigmentation, as well as malformations of the head, tail, and eyes. By integrating these abnormalities using the Integrated Biological Response (IBRv2) and General Morphological Score (GMS) indices, we were able to determine that ZFEs exposed to 200 mg/L (T9) exhibited the most pronounced biological response in comparison with the other groups. In the comparative transcriptomic analysis, 66 genes were upregulated, and 246 genes were downregulated in the group exposed to 200 mg/L compared with the control group. In the upregulated genes, we identified several gene ontology-enriched terms, such as response to xenobiotic stimuli, cellular response to chemical stimulus, transcriptional regulation, pigment metabolic process, erythrocyte differentiation and embryonic hemopoiesis, extracellular matrix organization, and chondrocyte differentiation involved in endochondral bone morphogenesis, among others. In the down-regulated genes, we found many genes associated with nervous system processes, sensory and visual perception, response to abiotic stimulus, and the nucleoside phosphate biosynthetic process. The probable connections among the morphological changes observed in the transcriptome are thoroughly discussed. Our findings suggest that Sargassum spp. exposure can induce a wide negative impact on zebrafish embryos. Environ Toxicol Chem 2024;43:1075-1089. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Quality of life, disease burden and healthcare need of patients with vitiligo

With aprevalence of 0.5-2%, vitiligo is one of the most common skin disorders worldwide with loss of pigment. The skin disease has adisfiguring, often stigmatising character and is often associated with psychosocial distress. To provide an overview of the psychosocial impairment, disease burden and resulting health care needs of patients with vitiligo. Narrative review based on aliterature search in PubMed for the years 1996-2022 on disease burden, quality of life and stigmatization is provided. The search yielded 175 relevant original papers including clinical studies, meta-analyses and systematic reviews (n = 65) for the search period. Alarge number of studies document that vitiligo is associated with considerable psychosocial stress and relevant losses in quality of life. Problem areas particularly concern stigmatisation, sexual dysfunction, anxiety, reduced self-esteem and problems at work. The observed increased levels of anxiety and depression correlate with the severity and activity of vitiligo. Often, comorbidity also contributes to reduced self-esteem and social isolation. These factors determine ahigh need for care in arelevant proportion of those affected. Vitiligo is not primarily acosmetic problem, but adisease requiring treatment according to the World Health Organisation's definition of health as physical, mental and social well-being. The benefits of treatment options are to be measured by their effects on patient-reported outcomes.

Effect of Temperature on Photosynthetic Pigment Degradation during Freeze–Thaw Process of Postharvest of Celery Leaves

Celery (Apium graveolens L.) is a kind of green leaf vegetable with a large consumption demand in the food industry. It is a commonly used material in quick-frozen food stuffing such as dumplings and steamed stuffed. Fresh celery leaf blades and petioles are rich in photosynthetic pigments including chlorophyll and carotenoid, their contents are closely related to the quality of celery and its products. In order to explore the effects of freezing and thawing temperature and thawing time on the degradation of photosynthetic pigments in celery leaf blades and petioles, the changes in photosynthetic pigments during thawing storage were measured under different freezing and thawing temperatures. The results showed that lower freezing and thawing temperatures were beneficial to the preservation of photosynthetic pigments in celery leaf blades and petioles, and the loss of photosynthetic pigments enhanced with the increase in thawing temperature and thawing time. Under the cold storage condition of −80 °C, the loss rate of pigment substances can be reduced by nearly 20% compared with that of −18 °C, and −80 °C and 4 °C could be the best temperature combination of freezing and thawing. The content and degradation rate of photosynthetic pigments in celery leaf blades were higher than that in petioles during thawing, with a total chlorophyll loss rate reaching 35% during 6 to 12 h after thawing. The increase in temperature difference between freezing and thawing could aggravate the damage to the cell structure and the degradation of the pigment, as chlorophyll is more sensitive to temperature changes, and the degradation rate is significantly higher than that of carotenoids. From the perspective of delaying the degradation of photosynthetic pigments, the results of this study will provide potential references for the reasonable configuration of freezing and thawing temperatures in the process of storage and transportation of celery products.

Transcriptome analysis reveals molecular mechanisms underlying chloroplast biogenesis in albino Agave angustifolia plantlets.

Albino plants display partial or complete loss of photosynthetic pigments and defective thylakoid membrane development, consequently impairing plastid function and development. These distinctive attributes render albino plants excellent models for investigating chloroplast biogenesis. Despite their potential, limited exploration has been conducted regarding the molecular alterations underlying these phenotypes, extending beyond photosynthetic metabolism. In this study, we present a novel de novo transcriptome assembly of an albino somaclonal variant of Agave angustifolia Haw., which spontaneously emerged during the micropropagation of green plantlets. Additionally, RT-qPCR analysis was employed to validate the expression of genes associated with chloroplast biogenesis, and plastome copy numbers were quantified. This research aims to gain insight into the molecular disruptions affecting chloroplast development and ascertain whether the expression of critical genes involved in plastid development and differentiation is compromised in albino tissues of A. angustifolia. Our transcriptomic findings suggest that albino Agave plastids exhibit high proliferation, activation of the protein import machinery, altered transcription directed by PEP and NEP, dysregulation of plastome expression genes, reduced expression of photosynthesis-associated nuclear genes, disruption in the tetrapyrrole and carotenoid biosynthesis pathway, alterations in the plastid ribosome, and an increased number of plastome copies, among other alterations.

Knock-Out Mutatıon of Cat2 Drastıcally Reduced The Melatonın-Medıated Resıstance to Boron Toxıcıty in Arabıdopsıs thalıana

The role of catalase in resistance to boron toxicity after melatonin application (MEL) was investigated in Arabidopsis thaliana plants. Col-0 and cat2-2 plants were exposed to 50 μM MEL followed by boron toxicity (BT) in a medium containing 10 mM H 3BO 3. Pigment loss and accordingly chlorosis were reduced by melatonin under BT conditions, while they were more prominent in cat2-2 mutants. Moreover, TBARS and H 2O 2 contents, which increased due to BT, decreased as a result of melatonin application and the levels of these parameters in cat2-2 mutants were higher than the values in Col-0. Antioxidant enzyme activity of SOD and SOD1 gen transcript were induced by MEL under BT. Conversely, APX4, PER10 and CAT1 transcripts were down-regulated by MEL under BT. In addition, antioxidant enzyme activities and their transcript levels were lower than those of Col-0. Thus, we suggested that MEL scavenged ROS directly under BT. Melatonin also reduced the accumulation of boric acid in leaf tissues of Col-0, but not cat2-2. Finally, even though melatonin application provided a degree of endurance, the cat2 mutation resulted in increased sensitivity to BT.

543 - Early repigmentation of stable vitiligo through point-of-care melanocyte transfer using non-cultured autologous skin cell suspension

Abstract Introduction Vitiligo is an acquired depigmenting skin condition characterized by the loss of skin pigmentation, impacting 0.5% to 2% of the global population.1–3 Vitiligo presents as distinct depigmented patches resulting from autoimmune melanocyte destruction. Individuals with visual vitiligo lesions often experience negative body image, diminished self-confidence, discomfort, and overall lower quality of life (QoL).4 While there are medical treatment options available, these can be associated with poor efficacy and low medication compliance.4 Residual lesions after treatment may require surgical intervention which allows for melanocyte transplantation from an area that is pigmented to one that is lacking functional melanocytes. Through a point-of-care device, a non-cultured autologous skin cell suspension (ACSC) can be prepared using a small skin sample; the ASCS contains healthy melanocytes and is immediately applied onto skin treated with ablative laser to aid in the repigmentation of affected areas. Objective The objective of this study was to evaluate the one-time application of ASCS, with a 1:20 donor to treatment site expansion ratio, for the safe and effective repigmentation of stable vitiligo lesions. Methods A randomized, within-subject controlled, central observer-blinded study was conducted to compare the clinical performance of laser ablation, ASCS, and NB-UVB to NB-UVB alone for repigmentation of stable vitiligo lesions in adults. Subjects received NB-UVB phototherapy on both ASCS-treated and controlled lesions as per recommended by the Vitiligo Working Group. Repigmentation of ASCS-treated and control lesions were categorized by a Central Review Committee (CRC) of blinded dermatologists as one of the following: 0%-25%, 26%-50%, 51%-79%, or 80-100%. The primary effectiveness endpoint was defined as the proportion of lesions achieving ≥80% repigmentation for ASCS-treated versus control areas at Week 24. Early regimentation was assessed at Weeks 4 and 12 as a post hoc analysis. Results A significantly higher proportion of the ASCS-treated areas (36.0%, n = 9) compared to control-treated areas (0.0%) attained ≥80% repigmentation at Week 24 (P = 0.012). At Week 4, 30.4% (n = 7/23) of ASCS-treated areas had ≥26% repigmentation compared to 4.3% (n = 1/23) in the control areas. At Week 12, 56.5% (n = 13/23) of ASCS-treated areas had ≥26% repigmentation compared to 21.7% (n = 5/23) in the control areas. At Week 24, 64% (n = 16/25) of ASCS-treated areas had ≥26% repigmentation compared to 28% (n = 7/25) in the control areas. Conclusion A one-time treatment of ASCS, with the addition of NB-UVB, can result in excellent repigmentation results by 24 weeks, with most subjects seeing ≥26% repigmentation as early as 4 to 12 weeks.

The blue light-dependent LOV-protein LdaP of Dinoroseobacter shibae acts as antirepressor of the PpsR repressor, regulating photosynthetic gene cluster expression.

In the marine α-proteobacterium Dinoroseobacter shibae more than 40 genes of the aerobic anoxygenic photosynthesis are regulated in a light-dependent manner. A genome-wide screen of 5,605 clones from a D. shibae transposon library for loss of pigmentation and changes in bacteriochlorophyll absorbance identified 179 mutant clones. The gene encoding the LOV-domain containing protein Dshi_1135 was identified by its colorless phenotype. The mutant phenotype was complemented by the expression of a Dshi_1135-strep fusion protein in trans. The recombinantly produced and chromatographically purified Dshi_1135 protein was able to undergo a blue light-induced photocycle mediated by bound FMN. Transcriptome analyses revealed an essential role for Dshi_1135 in the light-dependent expression of the photosynthetic gene cluster. Interactomic studies identified the repressor protein PpsR as an interaction partner of Dshi_1135. The physical contact between PpsR and the Dshi_1135 protein was verified in vivo using the bacterial adenylate cyclase-based two-hybrid system. In addition, the antirepressor function of the Dshi_1135 protein was demonstrated in vivo testing of a bchF-lacZ reporter gene fusion in a heterologous Escherichia coli-based host system. We therefore propose to rename the Dshi_1135 protein to LdaP (light-dependent antirepressor of PpsR). Using the bacterial two-hybrid system, it was also shown that cobalamin (B12) is essential for the interaction of the antirepressor PpaA with PpsR. A regulatory model for the photosynthetic gene cluster in D. shibae was derived, including the repressor PpsR, the light-dependent antirepressor LdaP and the B12-dependent antirepressor PpaA.

The Transposition of Insertion Sequences in Sigma-Factor- and LysR-Deficient Mutants of Deinococcus geothermalis.

Some insertion sequence (IS) elements were actively transposed using oxidative stress conditions, including gamma irradiation and hydrogen peroxide treatment, in Deinococcus geothermalis, a radiation-resistant bacterium. D. geothermalis wild-type (WT), sigma factor gene-disrupted (∆dgeo_0606), and LysR gene-disrupted (∆dgeo_1692) mutants were examined for IS induction that resulted in non-pigmented colonies after gamma irradiation (5 kGy) exposure. The loss of pigmentation occurred because dgeo_0524, which encodes a phytoene desaturase in the carotenoid pathway, was disrupted by the transposition of IS elements. The types and loci of the IS elements were identified as ISDge2 and ISDge6 in the ∆dgeo_0606 mutant and ISDge5 and ISDge7 in the ∆dgeo_1692 mutant, but were not identified in the WT strain. Furthermore, 80 and 100 mM H2O2 treatments induced different transpositions of IS elements in ∆dgeo_0606 (ISDge5, ISDge6, and ISDge7) and WT (ISDge6). However, no IS transposition was observed in the ∆dgeo_1692 mutant. The complementary strain of the ∆dgeo_0606 mutation showed recovery effects in the viability assay; however, the growth-delayed curve did not return because the neighboring gene dgeo_0607 was overexpressed, probably acting as an anti-sigma factor. The expression levels of certain transposases, recognized as pivotal contributors to IS transposition, did not precisely correlate with active transposition in varying oxidation environments. Nevertheless, these findings suggest that specific IS elements integrated into dgeo_0524 in a target-gene-deficient and oxidation-source-dependent manner.

Tumor Pigmentation Does Not Affect Light-Activated Belzupacap Sarotalocan Treatment but Influences Macrophage Polarization in a Murine Melanoma Model.

Pigmentation in uveal melanoma is associated with increased malignancy and is known as a barrier for photodynamic therapy. We investigated the role of pigmentation in tumor behavior and the response to light-activated Belzupacap sarotalocan (Bel-sar) treatment in a pigmented (wild type) and nonpigmented (tyrosinase knock-out [TYR knock-out]) cell line in vitro and in a murine model. The B16F10 (TYR knock-out) was developed using CRISPR/Cas9. After the treatment with light-activated Bel-sar, cytotoxicity and exposure of damage-associated molecular patterns (DAMPs) were measured by flow cytometry. Treated tumor cells were co-cultured with bone marrow-derived macrophages (BMDMs) and dendritic cells (DCs) to assess phagocytosis and activation. Both cell lines were injected subcutaneously in syngeneic C57BL/6 mice. Knock-out of the tyrosinase gene in B16F10 led to loss of pigmentation and immature melanosomes. Pigmented tumors contained more M1 and fewer M2 macrophages compared with amelanotic tumors. Bel-sar treatment induced near complete cell death, accompanied with enhanced exposure of DAMPs in both cell lines, resulting in enhanced phagocytosis of BMDMs and maturation of DCs. Bel-sar treatment induced a shift to M1 macrophages and delayed tumor growth in both in vivo tumor models. Following treatment, especially the pigmented tumors and their draining lymph nodes contained IFN-gamma positive CD8+T cells. Pigmentation influenced the type of infiltrating macrophages in the tumor, with more M1 macrophages in pigmented tumors. Belzupacap sarotalocan treatment induced immunogenic cell death and tumor growth delay in pigmented as well as in nonpigmented models and stimulated M1 macrophage influx in both models.

Early Repigmentation of Stable Vitiligo through Point-of-Care Melanocyte Transfer Using Non-Cultured Autologous Skin Cell Suspension

Introduction: Vitiligo is an acquired depigmenting skin condition characterized by the loss of skin pigmentation, impacting 0.5% to 2% of the global population.1,2 Vitiligo presents as distinct depigmented patches resulting from autoimmune melanocyte destruction. Individuals with visual vitiligo lesions often experience negative body image, diminished self-confidence, discomfort, and overall lower quality of life (QoL).3 While there are medical treatment options available, these can be associated with poor efficacy and low medication compliance.4 Residual lesions after treatment may require surgical intervention which allows for melanocyte transplantation from an area that is pigmented to one that is lacking functional melanocytes. Through a point-of-care device, a non-cultured autologous skin cell suspension (ACSC) can be prepared using a small skin sample; the ASCS contains healthy melanocytes and is immediately applied onto skin treated with ablative laser to aid in the repigmentation of affected areas. The objective of this study was to evaluate the one-time application of ASCS, with a 1:20 donor to treatment site expansion ratio, for the safe and effective repigmentation of stable vitiligo lesions. Methods: A randomized, within-subject controlled, central observer-blinded study was conducted to compare the clinical performance of laser ablation, ASCS, and NB-UVB to NB-UVB alone for repigmentation of stable vitiligo lesions in adults. Subjects received NB-UVB phototherapy on both ASCS-treated and controlled lesions as per recommended by the Vitiligo Working Group. Repigmentation of ASCS-treated and control lesions were categorized by a Central Review Committee (CRC) of blinded dermatologists as one of the following: 0%-25%, 26%-50%, 51%-79%, or 80-100%. The primary effectiveness endpoint was defined as the proportion of lesions achieving ≥80% repigmentation for ASCS-treated versus control areas at Week 24. Early regimentation was assessed at Weeks 4 and 12 as a post hoc analysis. Results: A significantly higher proportion of the ASCS-treated areas (36.0%, n = 9) compared to control-treated areas (0.0%) attained ≥80% repigmentation at Week 24 (P = 0.012). At Week 4, 30.4% (n = 7/23) of ASCS-treated areas had ≥26% repigmentation compared to 4.3% (n = 1/23) in the control areas. At Week 12, 56.5% (n = 13/23) of ASCS-treated areas had ≥26% repigmentation compared to 21.7% (n = 5/23) in the control areas. At Week 24, 64% (n = 16/25) of ASCS-treated areas had ≥26% repigmentation compared to 28% (n = 7/25) in the control areas. Conclusion: A one-time treatment of ASCS, with the addition of NB-UVB, can result in excellent repigmentation results by 24 weeks, with most subjects seeing ≥26% repigmentation as early as 4 to 12 weeks.

Flexi-chambers and 3D photogrammetry effectively measure coral fragment physiology in situ

Non-invasive techniques for measuring the physiological performance of corals in situ are important for understanding responses to changing environmental conditions. Two such methods are the ‘flexi-chamber’ and three-dimensional (3D) photogrammetry. While these have been verified for coral colonies, they have not been tested on coral fragments which are commonly used in field experiments. This study aimed to determine if these methods can effectively measure respiration, photosynthesis, and growth of fragments of massive and sub-massive coral species in the intertidal and subtidal habitats in Park Rynie, South Africa (30.3167° S, 30.7333° E). Differences in respiration and photosynthesis rates between species and habitat were successfully measured using the flexi-chambers. The coral fragments did not show any visual signs of stress (excess mucus production or loss of pigmentation) during the 3-h incubations or an hour after the incubations. 3D models were successfully constructed for all fragments. This study showed that flexi-chambers and 3D photogrammetry can be effectively used to measure the respiration, photosynthesis, and growth of individual coral fragments (3 cm > 4 cm) of different morphology and habitats. The combination of the two methods permits measures of fundamental physiological processes to be attained at relatively low cost and low complexity. This will facilitate studies of a wide range of coral species in situ generating more knowledge on responses to environmental variability.

High temporal resolution of hydrogen peroxide (H2O2) dynamics during heat stress does not support a causative role in coral bleaching

Human-induced climate change is causing ocean warming that triggers the breakdown of the coral–algal symbiosis. The proximate cause of this phenomenon, known as coral bleaching, is commonly attributed to the overproduction of reactive oxygen species (ROS) by the thermally stressed photosynthetic algal symbionts. However, direct evidence that algal ROS production (e.g., in the form of H2O2) and coral physiological stress are the ultimate cause of bleaching remains ambiguous. Here, we investigated the temporal dynamics of H2O2 and oxygen (O2) concentrations during thermally induced coral bleaching to disentangle cause from consequence. Microsensors at the tissue interface of Pocillopora damicornis measured H2O2 and O2 concentrations while exposing single nubbins to baseline temperatures (30 °C) and to minor (33 °C), moderate (36 °C), and high (39 °C) levels of acute heat stress using the Coral Bleaching Automated Stress System (CBASS). We show that a temporary decline in O2 concentration, accompanied by a declining photosynthetic efficiency and loss of Symbiodiniaceae and pigmentation, is the initial response to moderate thermal stress. This response was neither provoked nor followed by an increased H2O2 concentration at the coral tissue interface. A steady light-independent increase of H2O2 was only detected during high heat stress, resulting in the complete and permanent loss of photosynthetic activity. Our findings do not support a direct connection between algal photodamage and an increase in H2O2 concentration during thermally induced bleaching and suggest that more research on the function of H2O2 is warranted. This notion is further substantiated by the observation of an additional source of H2O2, likely oxidative bursts, that were common at the baseline temperature and under minor heat stress, while their occurrence decreased at moderate and high heat stress. Resolving the multifaceted and dynamic roles of H2O2 in coral bleaching is critical to better understand the response of the coral holobiont to thermal stress and identifying the processes underlying the breakdown of the coral–algal symbiosis.

Natural and artificial selection of multiple alleles revealed through genomic analyses.

Genome-to-phenome research in agriculture aims to improve crops through in silico predictions. Genome-wide association study (GWAS) is potent in identifying genomic loci that underlie important traits. As a statistical method, increasing the sample quantity, data quality, or diversity of the GWAS dataset positively impacts GWAS power. For more precise breeding, concrete candidate genes with exact functional variants must be discovered. Many post-GWAS methods have been developed to narrow down the associated genomic regions and, ideally, to predict candidate genes and causative mutations (CMs). Historical natural selection and breeding-related artificial selection both act to change the frequencies of different alleles of genes that control phenotypes. With higher diversity and more extensive GWAS datasets, there is an increased chance of multiple alleles with independent CMs in a single causal gene. This can be caused by the presence of samples from geographically isolated regions that arose during natural or artificial selection. This simple fact is a complicating factor in GWAS-driven discoveries. Currently, none of the existing association methods address this issue and need to identify multiple alleles and, more specifically, the actual CMs. Therefore, we developed a tool that computes a score for a combination of variant positions in a single candidate gene and, based on the highest score, identifies the best number and combination of CMs. The tool is publicly available as a Python package on GitHub, and we further created a web-based Multiple Alleles discovery (MADis) tool that supports soybean and is hosted in SoyKB (https://soykb.org/SoybeanMADisTool/). We tested and validated the algorithm and presented the utilization of MADis in a pod pigmentation L1 gene case study with multiple CMs from natural or artificial selection. Finally, we identified a candidate gene for the pod color L2 locus and predicted the existence of multiple alleles that potentially cause loss of pod pigmentation. In this work, we show how a genomic analysis can be employed to explore the natural and artificial selection of multiple alleles and, thus, improve and accelerate crop breeding in agriculture.

Study of the metallome and transcriptome of a degenerating cellular model of the retinal pigment epithelium

Aims/Purpose: To study the changes on the metallome and transcriptome of a cellular model of the retinal pigment epithelium (RPE) during its in vitro degeneration after 4 months in culture.Methods: Primary cultures of human fetal RPE cells were established in P12 transwell inserts and cultured for 4 months. Cell pigmentation and barrier function was followed up using optical microscopy and measurement of the transepithelial electrical resistance (TEER). Samples were collected at 21, 91 and 133 days in culture and analysed for gene expression, metal homeostasis of Ca, Na, P, Mg and P, and extracellular deposit formation through RNA sequencing (RNA‐Seq), elemental mass spectrometry (ICP‐MS) and immunocytochemistry assays, respectively.Results: RPE cells formed a differentiated monolayer at 21 days in culture, expressing specific genes and proteins of RPE and giving increasing TEER values. However, after 133 days in culture, loss of tight junction proteins (i.e. CLDN19 and BEST1) and electrical resistance was seen, together with loss of pigmentation and increase of apolipoprotein E deposition in the extracellular space. Gene expression analysis showed an enrichment on apoptotic processes, biomolecule phosphorylation, and signs of epithelial‐to‐mesenchymal transition (EMT). Degeneration of RPE cells concurred with an increase of Na and P content in the cytosol and decrease of Mg, while a decrease of Mg, P and Cu was determined in the insoluble fraction of cells. Time‐dependent changes of metals were accompanied with the alteration of metal transporters and antioxidant enzymes using metals as cofactors.Conclusions: Degeneration of RPE cells in culture was characterized by depigmentation of cells, improper barrier function, downregulation of antioxidant protection, loss of epithelial phenotype, and changes on the levels of Na, P, Mg and Cu, as well as of the expression of their homeostatic proteins.

Chemical composition and antifungal activity of Capsicum pepper aqueous extracts against plant pathogens and food spoilage fungi.

Capsicum pepper is a rich source of phytochemical compounds such as capsaicinoids, phenols, flavonoids, and so forth. Due to their antimicrobial and antioxidant potential all of these compounds have been assessed and used for both human and plant health benefits. Herein, three fresh varieties of Capsicum annuum (Cacho de Cabra, Bell pepper, and Hungarian Wax varieties) and one fresh and ripe variety of C. baccatum (Cristal) were evaluated. Capsaicin, dihydrocapsaicin, nordihydrocapsaicin and the phenolic content of Capsicum spp. extracts were characterised. The antifungal potential of capsaicinoids and antioxidant activities, and the ecotoxicity of each Capsicum spp. extract, using the model Galleria mellonella, were also evaluated. Phytochemical analyses showed that the Cristal and Hungarian Wax varieties presented the highest amount of capsaicin, dihydrocapsaicin, and nordihydrocapsaicin; while Bell Pepper had the highest phenol content and antioxidant activity. Capsaicinoids' standards and Capsicum spp. extracts showed fungistatic activity against the fungal strains assessed. For the fungal strains assessed, the fungistatic activities of capsaicinoids' standards were higher than those observed in Capsicum spp. extracts. The Hungarian Wax extracts inhibited slightly the growth of Aspergillus niger MUM05.11 and Fusarium oxysporum MUM16.143. Similarly, A. niger, F. oxysporum, Rhizopus arrhizus MUM16.05 and Alternaria sp. UFRO17.178 had their growth retarded by the use of Cacho de Cabra and Cristal extracts. Noticeable changes were observed in the fungal strains' morphologies, such as the presence of fragile fungal structures, pigmentation loss, variation in the reproductive structures size and the conidia number. Capsicum extracts weaken the growth of fungi, indicating their fungistatic potential. Considering the fungistatic potential and non-ecotoxicity of these extracts, it is possible to suggest their use as a tool for pest management in the agri-food sector, controlling the growth and reproduction of fungi without posing a risk to non-target biodiversity.

Quorum quenching activity of endophytic Bacillus sp. EBS9 from Tecomella undulata and its biocontrol applications

This study investigates the quorum quenching (QQ) activity of an endophytic bacterium, Bacillus sp. EBS9, isolated from the native medicinal plant Tecomella undulata of Rajasthan, and its biocontrol potential against the soft rot pathogen Pectobacterium carotovorum subsp. carotovorum (Pcc). QQ activity was confirmed by the loss of violacein pigment in Chromobacterium violaceum (MCC 2290). Quorum quenching metabolites were extracted using ethyl acetate, and the Quorum Quenching Extract (QQE) demonstrated positive activity in assays with C. violaceum CV026 (MCC 2216). HRLC-MS analysis identified diketopiperazines, L,L-Cyclo (leucylprolyl) and Cyclo (L-Phe-L-Pro), which are N-acyl homoserine lactones (AHLs) antagonists competing for LuxR receptor binding sites. In vitro and in planta assays evaluated QQB's biocontrol potential using treatment I (Pcc), treatment II (Pcc + QQB), and a control (sterile water). In the in vitro soft rot attenuation assay showed that treatment I caused severe maceration in vegetable slices, particularly in radish, exhibiting the highest maceration diameter (25.33 ± 3.52 mm) and percentage (46.14 ± 5.70 %). However, co-inoculation with QQB significantly reduced maceration across all tested vegetables. In the plate assay, germination rates decreased to approximately 50 % in both Vigna radiata and Raphanus sativus for treatment I, but improved to 86.67 % in treatment II. The seed vigour and germination indices also improved with QQB treatment in both plant species. In the pot assay after 30 days, in contrast to a 50 % decrease in root and shoot lengths in treatment I, treatment II led to a substantial recovery, with root lengths increase by 112.07 % and 138.76 %, while shoot length by 315.65 % and 163.63 % in V. radiata and R. sativus, respectively. This study highlights the QQ and biocontrol potential of Bacillus sp. EBS9 against P. carotovorum (Pcc), suggesting its promise in effective management of phytopathogens, which is crucial for agricultural productivity while minimizing environmental impact.

Transposon insertion in pmel17 rewired skin and muscle transcriptomes in Mozambique tilapia

The pmel17 gene plays a crucial role in melanin pigmentation. Our previous studies showed that in Mozambique tilapia, a transposon inserted into the 3′ untranslated region (3′ UTR) of pmel17 resulted in the silencing of pmel17 and led to the loss of melanin pigments (golden mutant phenotype). Additionally, the transposon insertion caused reduced growth performance and increased locomotion. In this study, to investigate the mechanisms underlying these phenotypic changes, we sequenced transcriptomes of the skin and muscle samples collected from wildtype and mutant tilapias. A total of 51 and 141 differentially expressed genes (DEGs) were identified in the skin and muscle transcriptomes, respectively. DEGs in the skin were primarily down-regulated in golden genotypes and associated with neural crest development and melanin pigmentation pathways. Besides these DEGs involved in the classic melanin pigmentation pathway of vertebrates, 14 DEGs were also observed to be related to melanogenesis. In muscle transcriptomes, there was an enrichment of GO terms associated with growth factors and cellular lipid catabolic processes. Specifically, DEGs related to growth factor binding exhibited a down-regulation, while those related to lipid metabolism showed an up-regulation in mutant genotypes. These findings agree with observed phenotypic changes. Furthermore, several DEGs associated with muscle function and mobility were up-regulated. Our study sheds light on how a single mutation in a gene can modulate multiple phenotypes by rewiring gene regulation networks. The research also provides valuable insights into the complex genetic mechanisms underlying the regulation of diverse phenotypic traits by a single gene.

SIRT7 Inhibits Melanin Synthesis of PIG1 and PIG3V by Suppressing the Succinylation of EZR.

Vitiligo is an autoimmune disease characterized by loss of skin pigmentation and currently has no effective treatment. This study aimed to investigate the function of SIRT7, being an important desuccinylase mediating multiple disease progression, and its mechanism in vitiligo progression. Normal human melanocytes (NHM) PIG1 and vitiligo human melanocytes (VHM) PIG3V were utilized in this research. The role of sirtuin 7 (SIRT7) and Ezrin (EZR) on melanin synthesis was investigated by detecting tyrosinase activity, melanin content, α-MSH levels, and the protein levels of melanin-related markers. The function of EZR was identified via rescue experiments, while the underlying mechanism was investigated via bioinformatic analysis, co-immunoprecipitation (co-IP), immunoprecipitation (IP), and Western blot techniques. Results showed that only SIRT7 was highly expressed in vitiligo human melanocytes, where knockingdown SIRT7 translated into increased melanin synthesis in melanocytes. Mechanistically, SIRT7 knockdown promoted the succinylation of EZR at the Lys (K)60 site. Moreover, overexpressing EZR induced higher melanin synthesis in melanocytes, while its knocking down exerted the opposite effect by inhibiting SIRT7 knockdown-induced melanin synthesis. SIRT7 inhibited melanin synthesis in melanocytes by suppressing the succinylation of EZR. These findings are envisaged to provide a novel theoretical basis for vitiligo treatment.