Brown Pigment Research Articles

Metabolites analysis and new bioactive pigments from a Monascus purpureus strain with low citrinin

A Monascus purpureus strain with high mycelial biomass and no detected citrinin in liquid fermentation was selected from 20 strains. HPLC-DAD-HRMS analysis revealed that the EtOAc extract of the fermented mash contained 2 unknown compounds and 11 known metabolites of Monascus fungi. Isolations with preparative and semi-preparative HPLC resulted in four brownish red pigments. The two unknown pigments were identified with HRMS, CD, ECD, 1D and 2D NMR, and designated as monascuskaolin A (3) and B (8). The two known compounds were verified with 13C NMR as monascusazaphilone C and monasfluol B. Result of bioactivity tests showed that the two new pigments were able to significantly reduce the transcription levels of IL-1β, TNF-α, and TGF-β, and significantly promote the proliferation of 293 T cells, suggesting that they have anti-inflammatory function and may be good for human kidney. Metabolites studies suggested that M. purpureus RCEF7056 is a safe strain with functional food utilization potential.

Entophysalis in the Rhynie chert (Lower Devonian, Scotland): implications for cyanobacterial evolution

AbstractThe ∼407-myr-old Rhynie chert of Scotland contains exquisite body fossils of land plants, animals and microorganisms, which provide our earliest reasonably complete snapshot of a Phanerozoic terrestrial ecosystem. These fossils have been instrumental to our understanding of the ‘greening of the land’, a major transition in the history of the Earth–life system. Among the primary producers preserved in the chert are cyanobacteria, of which only a fraction have been formally described. Here, we report the occurrence of the colony-forming cyanobacterium Eoentophysalis in the Rhynie chert. To our knowledge, this represents the first bona fide record of Entophysalidaceae from any post-Cambrian fossil assemblage or any non-marine fossil assemblage of any age. The Rhynie Eoentophysalis appears remarkably similar in appearance both to modern marine and freshwater Entophysalis ssp. and to Eoentophysalis belcherensis, a shallow-marine fossil from the ∼2 Ga Belcher Group of Canada that is perhaps the oldest convincing cyanobacterium on record. Darkened cell envelopes in the Rhynie Eoentophysalis correspond well with both E. belcherensis and modern Entophysalis, whose cell envelopes often contain the photoprotective brown pigment scytonemin. The occurrence of Eoentophysalis in the Rhynie chert supports previous claims that the fossilisable traits of entophysalid cyanobacteria are evolutionarily static through geological time. These organisms may be such effective generalists that major changes in their environment – in this case, the transition to a fully non-marine habitat – have not imposed significant selection pressure on these traits.

Non-enzymatic browning of lotus rhizome juice during sterilization mediated by 1,2-dicarboxyl and heterocyclic compounds.

Lotus rhizome juice (LRJ) is prone to Maillard reaction (MR) and caramelization, which tend to cause quality decline and lower consumer acceptance of the product. 1,2-dicarbonyl compounds (DCs) and heterocyclic compounds have attracted increasing attention as key intermediates responsible for the formation of brown pigments during MR and caramelization. However, little is known about the effects of these two types of compounds on brown pigments in LRJ during sterilization. This study quantified the changes in brown intensity (A420), DCs, and heterocyclic compounds before and after spiking, and identified the precursors and intermediates for brown pigment formation as well as the formation pathways of the intermediates. The spiking experiments suggested that spiking with fructose resulted in more 3-deoxyglucosone (3-DG) and 2,3-Dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one (DDMP), while that with lysine led to more glucosone (GS) and 2,3-butanedione (2,3-BD) in LRJ. The addition of glucose, asparagine, and glutamine significantly promoted the formation of 5-hydroxymethylfurfural (HMF), while that of glucose, lysine, and asparagine resulted in more norfuraneol. Spiking with reducing sugars and amino acids promoted both glyoxal (GO) and methylglyoxal (MGO), and the effect of glucose on GO was particularly significant. Correlation analysis showed that A420 had the highest correlation with 3-DG in the fructose- and lysine-spiked group, and with HMF in the glucose-, asparagine-, and glutamine-spiked groups. This study revealed that fructose, glucose, asparagine, glutamine, and lysine were essential precursors of MR and caramelization in LRJ during sterilization. 3-DG and DDMP were mainly produced by caramelization with fructose as the primary precursor, whereas GS and 2,3-BD were primarily formed via MR under the catalysis of lysine. MR and caramelization were the main formation pathways of HMF (catalyzed by asparagine and glutamine) and norfuraneol (catalyzed by lysine and asparagine), with glucose as the critical precursor. MGO was mainly produced by MR or caramelization, while caramelization was the main formation pathway of GO with glucose as the precursor. Additionally, for brown pigment formation from fructose and lysine, 3-DG was identified as the most crucial intermediate, while for that from glucose, asparagine, and glutamine, HMF was found to be the most important intermediate. This article is protected by copyright. All rights reserved.

Functional allele of a MATE gene selected during domestication modulates seed color in chickpea.

Seed color is one of the key target traits of domestication and artificial selection in chickpeas due to its implications on consumer preference and market value. The complex seed color trait has been well dissected in several crop species; however, the genetic mechanism underlying seed color variation in chickpea remains poorly understood. Here, we employed an integrated genomics strategy involving QTL mapping, high-density mapping, map-based cloning, association analysis, and molecular haplotyping in an inter-specific RIL mapping population, association panel, wild accessions, and introgression lines (ILs) of Cicer gene pool. This delineated a MATE gene, CaMATE23, encoding a Transparent Testa (TT) and its natural allele (8-bp insertion) and haplotype underlying a major QTL governing seed color on chickpea chromosome 4. Signatures of selective sweep and a strong purifying selection reflected that CaMATE23, especially its 8-bp insertion natural allelic variant, underwent selection during chickpea domestication. Functional investigations revealed that the 8-bp insertion containing the third cis-regulatory RY-motif element in the CaMATE23 promoter is critical for enhanced binding of CaFUSCA3 transcription factor, a key regulator of seed development and flavonoid biosynthesis, thereby affecting CaMATE23 expression and proanthocyanidin (PA) accumulation in the seed coat to impart varied seed color in chickpea. Consequently, overexpression of CaMATE23 in Arabidopsis tt12 mutant partially restored the seed color phenotype to brown pigmentation, ascertaining its functional role in PA accumulation in the seed coat. These findings shed new light on the seed color regulation and evolutionary history, and highlight the transcriptional regulation of CaMATE23 by CaFUSCA3 in modulating seed color in chickpea. The functionally relevant InDel variation, natural allele, and haplotype from CaMATE23 are vital for translational genomic research, including marker-assisted breeding, for developing chickpea cultivars with desirable seed color that appeal to consumers and meet global market demand.

Distillery Effluent Melanoidin Decolorization Induced by a Yeast Strain <i>Candida tropicalis</i> (Y-2)

Molasses is used in the manufacturing of ethanol at sugarcane distilleries, which also produces a significant volume of effluent with melanoidin pigment and high BOD, COD, and pH. Melanoidin is a dark brown pigment that may be treated before disposal since it has a number of harmful consequences. This study’s objective was to identify possible melanoidin pigment-decolorizing yeast from natural resources and optimize it for various physiological, chemical, and dietary factors. From the various samples taken from the neighbouring distillery site, a total of 15 yeasts were isolated. Candida tropicalis (Y-2) was the name of the yeast strain that had the most colour decolorization. Within 32 hours of incubation, this strain of yeast displayed maximal decolorization (83%) at 35°C with 0.5% glucose, 0.5% peptone, 0.05% MgSO4, and 0.01% KH2PO4 pH-5. This yeast displayed maximal decolorization in the shortest amount of time while using the least quantity of carbon and nitrogen sources. This yeast strain may be used on an industrial scale to decolorize melanoidin since it is exceedingly successful. This is the first investigation of this unique strain of yeast that decolorizes spent wash.

Black garlic particles as a natural pigment and emulsifier in a Pickering emulsion based low fat innovative mayonnaise: Improved rheology and bioactivity

Black garlic is rich in brown pigments and Maillard reaction products are known for antioxidant activity and health promoting effects. In the present investigation, we report a facile strategy for fabricating low-fat innovative mayonnaise (IM) using black garlic particles (BGP) as a natural pigment, and a functional ingredient. Whey protein concentrate and high methoxyl pectin at optimized concentrations were utilized for fabricating an IM which served as a control. IM5 and IM10 were ternary composites constituting whey protein, high methoxyl pectin along with BGP (@5 and 10% respectively). The formulation IM10 (BGP @10%) showed high firmness and low spreadability quotient, hence IM5 was taken forward for fabrication for two more variants namely IM-J (using low methoxyl pectin (LMP) from jackfruit peels) and IM-C (LMP from citrus). The effect of BGP and LMP on the functional quality of IM was confirmed through zeta potential, antioxidant activity, textural, rheological, and microscopic evaluation. Fluorescence microscopy confirmed the presence of solid particles over the fat phase of IM, while interaction of pectin and whey proteins was demonstrated through fluorescence emission spectroscopy which clearly displayed stabilization of IM through the formation of Pickering emulsion. Pronounced difference in color and flavor score with BGP established high sensory scores in IM5, IM-J, and IM-C. Rheology supported the stabilizing effects of LMP in IM-J and IM-C in terms of speedy recovery of thixotropy, with recovering storage modulus (G′). Enhanced viscosity of IM-C and IM-J further corroborated the dual effect of LMP and BGP in improving emulsifying and functional quality of IM. Enhanced oxidative stability of IM was established by reduced peroxide and Totox values. Overall our results suggest the promising applications of black garlic as functional ingredient in protein and pectin based Pickering emulsions.

Unveiling the Secrets of an Artwork through Non-Invasive Investigations—Case Study of a 19th-Century Female Portrait

This article aims to present the results of the investigations performed on a 19th-century oil painting on canvas belonging to the Conservation and Restoration Department of the University of Art and Design in Cluj-Napoca, Romania. The artwork depicting the portrait of a lady originating from an important Irish noble family (Judith Bunbury, 1785–1861) has been investigated using only non-invasive methods. The investigation protocol included digital photography in different light sources at different wavelengths, which was used to document the current condition of the painting, UV fluorescence, which highlighted the previous improper retouches and the presence of a varnish coat, Infrared reflectography, which brought to light the underdrawing made by the artist and X-ray Fluorescence (XRF) spectroscopy, an elemental analysis technique which indicated the chemical composition of the pigments, suggesting the use of lead white, a barium white pigment, yellow and red ochre, vermilion, cobalt blue, and a manganese-based brown pigment. The results of this entirely non-invasive investigation approach helped in choosing the most appropriate conservation and restoration methodology for the artwork.

The genus Schaereria Körb. in Australia

AbstractFive species of Schaereria Körb. are known to occur in Australia (including Tasmania). The new species S. australis Kantvilas is described from alpine Tasmania and New South Wales; it is characterized by a thallus lacking lichen substances, apothecia with only brown pigments, and ellipsoid, uniseriate ascospores, 10−17 × 6−9 μm. Also treated are: S. bullata Kantvilas, endemic to Tasmania; S. dolodes (Nyl. ex Hasse) Schmull & T. Sprib., first described from North America and recorded here for the first time from the Southern Hemisphere (Tasmania); the bipolar S. fuscocinerea (Nyl.) Clauzade & Cl. Roux and the Australian endemic S. xerophila Rambold & H. Mayrhofer, both recorded for the first time from Tasmania. The species are illustrated and an identification key is provided.

Comparative analysis of phenotypes in the sea cucumber Cucumaria frondosa from the Arctic and the NW Atlantic

Research on ecologically and economically important sea cucumbers has been focused on temperate and tropical species, leaving those from higher latitudes, such as the Canadian Arctic, understudied. This study compared the phenotypic characters of the sea cucumber Cucumaria frondosa sampled from populations of the Arctic (Hudson Bay, Nunavut) and Northwest Atlantic (Newfoundland). Organ indices and external and internal tissue pigmentation, and various biochemical metrics (proximate composition, lipids, fatty acids, amino acids, lipid-soluble vitamins, carotenoids) were assessed. All sea cucumbers had similar total body weights, but those from Newfoundland had heavier gonads and body walls, while the tissue pigmentation of Nunavut individuals was distinctive (more red and yellow trivium, darker brown pigmentation). Moisture and ash contents of sea cucumbers were similar between locations; however, protein and lipid contents in Nunavut samples were 12 and 50% lower, respectively. Inversely, Nunavut samples contained more ω-3 fatty acids, a greater degree of lipid desaturation, double the concentration of proline and vitamin A, and more carbohydrates and astaxanthin than Northwest Atlantic samples. Examining phenotypic variability across latitudes and longitudes, including into the Arctic, highlights unique physical and biochemical features attributed to this specific environment and may support the sustainable development of sea cucumber fisheries.

The cross-linking ability of dialdo-galactose in food processing condition

Cross-linking is a popular strategy to tailor the mechanical profile of foods and materials. Dialdo-galactose (DAG) is a hetero-sugar bearing two aldehyde groups that could potentially cross-link amino-group rich systems. In this study, we proved even in undesirable Maillard reaction condition, DAG is a very reactive Maillard substrate that could effectively cross-link all the tested foods, enhance their mechanical strength, and generate brown pigments during cross-linking. In particular, DAG treated sea cucumber exhibited good stability against heat-induced deterioration. In addition, DAG treated collagen sausage casing was more elastic and flexible then glutaraldehyde (GA) treated ones. DAG also outperformed GA in generating stronger chitosan hydrogels with higher G’, and the DAG cross-linked chitosan film was more robust against acid-catalyzed decompositions. These results have not only confirmed DAG’s cross-linking ability in food processing condition, but also provided useful information for the development of new food cross-linking agents based on oxidized saccharides.

Proposal of a new dermoscopic criterion for pigmented basal cell carcinoma: a multicentre retrospective study.

Dermoscopy is widely used for the diagnosis of skin cancer and it increases the accuracy of basal cell carcinoma (BCC) detection. BCC dermoscopic criteria have been updated and divided into vascular, pigment-related, and non-vascular/non-pigment-related. Our multicenter retrospective study tested a new dermoscopic pigment-related characteristic to detect pigmented BCC (pBCC) [brown homogeneous blotches (BHB)]. Cases of pBCC were collected from the databases of IDI-IRCCS of Rome and from three Italian private dermatology centers. BHB are confined patches of brown uniform pigmentation without dermoscopic features (net, fat fingers, etc.) or other internal dermoscopic structures, except for occasional vascular ones like arborizing vessels or globules/dots. Melanocytic and non-melanocytic controls were used. We reviewed photos of 270 pigmented lesions (female 145; 51.8%), including 90 histopathologically verified pBCC and 180 control cases (90 melanocytic and 90 non-melanocytic). BHB were found in 61 cases of 90 pBCC patients. The results showed a 67.8 sensitivity, 93.3 specificity, 83.6 positive and 85.3 negative predictive values, posLR 10.2, negLR 0.3, odds ratio 29.4, p<0.001. Our multicentre retrospective analysis suggested the BHB may be a novel dermoscopic pBCC diagnosis criterion.

Dermoscopy of lichen nitidus: a study of 20 cases

Lichen nitidus (LN) is a chronic inflammatory lichenoid dermatosis, commonly seen in childhood or early adulthood. In this case series, we studied the various dermoscopic features of LN and correlate them with clinical variants, duration of disease and histopathology. A total of 20 patients of LN were studied. The mean age was 25.7 years with 45% and 55% male and female, respectively. The median duration of disease was 6 months. The dermoscopic findings seen on non-polarizing mode were-shiny elevated surface with absence of skin markings (100%), scaling (70%), radial ridges (50%) and central depression (35%). Findings seen on polarizing mode were-hypopigmentation (100%), brown shadow (70%), linear vessels (65%), accentuation of surrounding reticulate pigment network (65%), diffuse erythema (45%). Newer findings seen were central grey-brown structureless areas (30%), speckled brown pigment (40%), curvilinear vessels (50%), branching/serpentine vessels (20%), radial vessels (10%), white dots and streaks (30%) and ring-in-ring appearance (5%). LN presents fairly distinctive dermoscopic features and dermoscopy can be a non-invasive, painless aid in differentiating it from close clinical differentials and avoid the need for a biopsy, especially in children.

Study of clinicodermoscopic features of topical steroid damaged face patients

Background: Topical steroid dependent or damaged face is an alarming upcoming entity rampant in India due to over-the-counter availability of topical corticosteroids containing products. The present study aimed to study the clinical and dermoscopic changes in patients with topical steroid damaged face and to correlate them with potency and duration of application of the TCS. Methods: 80 patients visiting the dermatology OPD &amp; IPD at SAIMS Hospital &amp; PG Institute, Indore, with the chief complains of redness, itching, red raised lesions, burning, swelling, photosensitivity, pigmentation; with a history of application of topical corticosteroids of any potency on face for continuous 7 days or intermittent for 15 or more days were enrolled for the study. Results: Mean age of the patients was 31.5±8.13 years. Male to female ratio was 1:9. Twelve (15.2%) patients abused TCS for more than one year. Presenting complains of the patients were redness (82.5%), itching (66.3%), hypertrichosis (47.5%), pigmentation (66.3%), burning (38.8%) and acne (28.8%). The most common dermoscopy findings i.e., unpatterned brown pigmentation (86.3%), polygonal vessels (73.8%), fine scales (52.5%), hypertrichosis (53.8%), follicular plugs (32.5%), micropustules (15%) and ivory patches (11.3%) were observed in a statistically higher proportion of cases dermoscopically Conclusions: Dermoscopy in TSDF can help dermatologists in a multitude of ways from confirming the diagnosis to differentiating from other causes of red face and predicting the approximate duration of TCS abuse.

Pb(II)-inducible proviolacein biosynthesis enables a dual-color biosensor toward environmental lead.

With the rapid development of synthetic biology, various whole-cell biosensors have been designed as valuable biological devices for the selective and sensitive detection of toxic heavy metals in environmental water. However, most proposed biosensors are based on fluorescent and bioluminescent signals invisible to the naked eye. The development of visible pigment-based biosensors can address this issue. The pbr operon from Klebsiella pneumoniae is selectively induced by bioavailable Pb(II). In the present study, the proviolacein biosynthetic gene cluster was transcriptionally fused to the pbr Pb(II) responsive element and introduced into Escherichia coli. The resultant biosensor responded to Pb(II) in a time- and dose-dependent manner. After a 5-h incubation with Pb(II), the brown pigment was produced, which could be extracted into n-butanol. Extra hydrogen peroxide treatment during n-butanol extract resulted in the generation of a stable green pigment. An increased brown signal was observed upon exposure to lead concentrations above 2.93 nM, and a linear regression was fitted from 2.93 to 3,000 nM. Extra oxidation significantly decreased the difference between parallel groups. The green signal responded to as low as 0.183 nM Pb(II), and a non-linear regression was fitted in a wide concentration range from 0.183 to 3,000 nM. The specific response toward Pb(II) was not interfered with by various metals except for Cd(II) and Hg(II). The PV-based biosensor was validated in monitoring bioaccessible Pb(II) spiked into environmental water. The complex matrices did not influence the regression relationship between spiked Pb(II) and the dual-color signals. Direct reading with the naked eye and colorimetric quantification enable the PV-based biosensor to be a dual-color and low-cost bioindicator for pollutant heavy metal.

Effect of Oxalic Acid on Control of Post-harvest Browning of Litchi (Litchi chinensis L.)

Post-harvest browning of litchi is a common phenomenon that occurs due to enzymatic and non-enzymatic reactions. Enzymatic browning is primarily caused by polyphenol oxidase (PPO) activity, leading to the formation of brown pigments. Non-enzymatic browning is caused by the Maillard reaction between reducing sugars and amino acids. Factors such as temperature, humidity, and mechanical damage can accelerate browning. Proper handling, storage, and the use of antioxidants can help minimize post-harvest browning, extending the shelf life and maintaining the visual appeal of litchi fruits. The present investigation was laid out in the post-harvest laboratory of horticulture department, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj during the year 2022-2023. The experiment was laid out in the CRBD with 8 treatments and 3 replications. Litchi fruit, Cv. Purvi (about 80%- matured stage), were harvest from a Local market Prayagraj, fruit was selected for uniformity of size and colour, and blemished and diseased fruit were discarded. The selected fruit were dipped in different oxalic acid concentration solution (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0mM) and Bavistin (0.05mg) as the control) for 10 mint 4 h of harvest, and then air dried. Each 10 fruit of the treated fruit was packed into a plastic punnet and wrapped with a 0.2-mm polyethylene bag, and then stored in an ambient condition. Post-harvest storage studies revealed that under ambient and refrigerated storage conditions T8 Oxalic acid (4.0mM) + Bavistin (0.05%) treatment showed slower rate of reduction on fruit length (cm) and fruit weight (g), browning (%) were significantly affected by treatments. There was significant effect of treatments on chemical parameters like pH, TSS (0Brix), acidity (%), ascorbic acid (mg100g), reducing sugar under ambient and refrigerated storage at different day’s intervals.

Streptomyces marispadix sp. nov., isolated from marine beach sediment.

A novel actinomycetal strain, designated M600PL45_2T, was isolated from marine sediments obtained from Ingleses beach, Porto, on the Northern Coast of Portugal and was subjected to a polyphasic taxonomic characterisation study. The here described Gram-reaction-positive strain is characterised by the production of a brown pigment in both solid and liquid medium and forms typical helical hyphae that differentiate into smooth spores. The results of a phylogenetic analysis based on the 16S rRNA gene sequence indicated that M600PL45_2T has a high similarity to two members of the genus Streptomyces, Streptomyces bathyalis ASO4wetT (98.51 %) and Streptomyces daqingensis NEAU ZJC8T (98.44 %). The genome of M600PL45_2T has a size of 6 695 159 bp, a DNA G+C content of 70.71 mol% and 5538 coding sequences. M600PL45_2T grows at 15-37 °C and with a maximal growth rate between 25 °C and 30 °C. Growth at pH 6.0 to 9.0 with the optimal range between 6.0 and 7.5 was observed. M600PL45_2T showed a high salinity tolerance, growing with 0-10 % (w/v) NaCl, with best growth with 1-3% (w/v) NaCl. Major cellular fatty acids are iso-C15:0 (25.03 %), anteiso-C15:0 (17.70) and iso-C16:0 (26.90 %). The novel isolate was able to grow in media containing a variety of nitrogen and carbon sources. An antimicrobial activity screening indicated that an extract of M600PL45_2T has inhibitory activity against Staphylococcus aureus. On the basis of the polyphasic data, M600PL45_2T (= CECT 30365T = DSM 114036T) is introduced as the type strain of a novel species, that we named Streptomyces marispadix sp. nov.

CLINICAL CASE OF RECURRENT NEVUS

Abstract. Introduction. Recurrent nevus is a benign proliferation of melanocytes that occurs at the site of non-radical removal of a previously existing nevus. Recurrence rates range from 0.3% to 28% and most often occur within 6 weeks to 6 months after removal. Clinically recurrent nevus is characterized by uneven pigmentation with uneven edges in the area of the scar.&#x0D; Walton et al. began researching the phenomenon of recurrent nevus in 1957. In 1975, Kornberg and Ackerman reported that a pigmented recurrent nevus can resemble superficially spreading melanoma both clinically and histologically, and proposed the term pseudomelanoma to describe this benign phenomenon. Currently, the term is rarely used, but it motivates a thorough examination of patients with such a problem.&#x0D; Case presentation. Patient A. complained about the presence of a formation in the area of the outer surface of the right forearm, which has existed for many years, it was injured several times, but has recently changed the colour. On examination, a nodule up to 0.5 cm in size, heterogeneously pigmented, with peripheral erythema was found in the indicated place. During dermoscopy, chaotic unevenly distributed pigmentation, consisting of dots, globules, forming a cellular structure in a scattered manner is determined, zones of segmental radial lines are present as well. The vascular pattern in the central part of the formation is not defined, on the periphery it is represented by slightly noticeable point vessels. Digital post-processing using machine learning technology was carried out to improve visualization of blood supply. Multiple point, curved, and convoluted vessels with few branches around the formation, and several central vessels in the pigment cells are determined. Surgical removal of the tumor was performed with involvement of the erythema zone, taking into account the peculiarities of pigmentation and vascular pattern. The pathogistological structure is presented in the photomicrograph. The epidermis has a typical structure, with areas of slight acanthosis; hyperpigmentation of the basal layer is also observed. In the dermis, foci of brown pigment deposition, single lymphocytes, there are areas of intradermal lobular-horizontal fibrosis with angiomatosis and scattered lymphocytic infiltration. Taking into account the clinical data, there is a recurrence of a melanocytic nevus on the background of a skin scar (Recurrent neavus).&#x0D; Teaching point. Dermoscopy allows obtaining additional data for the differential diagnosis of recurrent nevus and recurrent melanoma. A recurrent nevus is characterized by relative symmetry of formation and a pattern of segmental radial lines. The formation is limited to the area of the scar and does not go beyond it. Also, in the case of recurrent melanoma, a continuous growth in dynamics and a later appearance of recurrence from the moment of intervention will be obvious.&#x0D; Conclusions. As clinical practice demonstrates, under certain circumstances, recurrent pigmentation can be observed in cases of nevi that have been traumatized. It will be visible both dermoscopically and pathohistologically. Sometimes it is difficult even for experts to distinguish between a highly irritated nevus and a melanoma.

Cutaneous Malignant Melanoma with Testicular Metastases in a Wild Rabbit (Oryctolagus cuniculus).

Melanocytic skin tumours have been rarely described in pet rabbits, and exposure to UV light in sparsely haired areas has been hypothesised to play a cancerogenic role. Here, we describe a case of cutaneous malignant melanoma arising from the skin of the scrotum in an 8-year-old male wild rabbit, with testicular metastases as an unusual metastatic site for melanoma reported in humans to date. The tumour was nearly 5 cm in size, firm, and highly pigmented, with multifocal superficial ulcerations and large areas of intratumoural necrosis. The adjacent testis was 1.5 cm, multinodular, and black, obscuring tissue morphology. Histologically, the dermis was expanded by an infiltrative, densely cellular neoplasm composed of nests and sheets of polygonal to spindle neoplastic melanocytes, supported by scant fibrovascular stroma. Neoplastic cells showed intermediate N/C ratio, moderate basophilic cytoplasm, often obscured by abundant brownish granular pigment, and eccentric nuclei with prominent nucleoli. Cellular pleomorphism and nuclear atypia were severe, and high mitotic activity was observed. Diffuse dermal lymphovascular invasion was also observed. The testis was delimited by a thin tunica albuginea, and the parenchyma was largely obscured in its morphology by densely packed neoplastic cells. Seminiferous tubules, lined with a thin basement membrane and containing neoplastic and scattered spermatogenic cells, were occasionally observed. Neoplastic cells within the skin and the testis were positive for HMB-45, Melan-A, and S-100. The growing popularity of rabbits as pets allows for a greater ability to accumulate data on the spontaneous occurrence of tumours in these animals. Furthermore, descriptions of the biological aspects of spontaneously occurring tumours may serve to improve current knowledge in animal species and humans in which the same neoplasm may occur.

A Case report of Oral Pigmentation - Post-inflammatory or Psoriasiform lesions.

Intraoral pigmentation occurs in various physiologic and pathologic conditions. Many of these are the manifestations of systemic diseases that too dermatologic conditions in specific. Here with reporting a case of intraoral brownish pigmentation in a young adult female who was treated for mild dermal lesions of psoriasis which was reported to be either post inflammatory pigmentation or psoriasiform oral manifestations. The pattern of mucosal pigmentation is nonspecific and there is lack of recent research regarding etiopathogenesis.

First Report of Fusarium citri Causing Postharvest Fruit Rot of Chayote in Mexico.

In November 2018, symptoms of brown rot were observed on chayote (Sechium edule) var. nigrum spinosum with a 20% disease incidence of 120 harvested fruits in the National Germplasm Bank of Sechium edule, located in the Centro Regional Universitario Oriente (CRUO) from the Chapingo Autonomous University (Huatusco, Veracruz, Mexico). For fungal isolation, pieces from symptomatic fruits were surface disinfected by immersion in a 1.5% NaClO solution for 2 min, rinsed in sterile distilled water, placed in Petri plates containing potato dextrose agar (PDA) amended with kanamycin sulfate, and incubated at 25ºC. Fusarium-like colonies were consistently isolated on PDA and five monoconidial isolates were obtained. A representative isolate was selected for morphological characterization, phylogenetic analysis, and pathogenicity tests. On PDA, colonies exhibited white and fluffy aerial mycelia, with diffused pale brown pigment in the center at 7 days of incubation at 25℃ in darkness. Macroconidia (n= 100) were hyaline, falcate, with 4 to 5 septa, measuring 23.9 to 31.9 × 2.9 to 4.2 μm, and foot-shaped basal cells. Microconidia and chlamydospores were absent. Morphological features were consistent with the description of the Fusarium incarnatum-equiseti species complex (Xia et al. 2019). The isolate was deposited as FUS2 in the Culture Collection of Phytopathogenic Fungi of the Laboratory of Plant Pathology at the Colegio de Postgraduados. For molecular identification, genomic DNA was extracted, and the internal transcribed spacer (ITS) region, partial sequences of translation elongation factor 1-alpha (EF1-α), and the second-largest subunit of RNA polymerase II (rpb2) genes were amplified, and sequenced with the primer sets ITS5/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone and Kohn 1999), and RBP2-5F/RPB2-7R (Liu et al. 1999), respectively. DNA sequences were edited in BioEdit 7.2 and compared with those in the NCBI nucleotide database. Alignments were implemented in MEGA X using reference sequences from Fusarium spp. A phylogenetic tree, including published ITS, EF1-α, and rpb2 sequence data, was constructed for the Fusarium incarnatum-equiseti species complex (FIESC) based on Maximum Likelihood. The sequences were deposited in GenBank (accession nos. ON878083, ON890421, and ON890420). The phylogenetic analysis grouped the isolate FUS2 within the F. citri clade. Pathogenicity of the fungus was verified on 10 healthy chayote fruits var. nigrum spinosum previously disinfested by immersion in a 1% NaClO solution for 3 min and washed in sterile water. A total of 5 mL of a conidial suspension (1 × 106 spores/ml) was sprayed on each whole fruit. Ten control fruit were sprayed with sterile distilled water. The fruits were kept in a moist plastic chamber at 25°C and 12 h light/dark for 30 days. All inoculated fruits developed water-soaked brown lesions (3 to 5 cm in diameter) covered with white mycelium at 15 days after inoculation, whereas no symptoms were observed on the control fruits. The fungus was consistently re-isolated only from the diseased fruits and found to be morphologically identical to the isolate used for inoculation, fulfilling Koch´s postulates. Fusarium citri has been associated with Capsicum sp. and mandarin orange in China, Triticum sp. in Iran, alfalfa in Denmark, and lettuce in the Czech Republic and Italy (Farr and Rossman 2022). To our knowledge, this is the first report of F. citri causing postharvest fruit rot of chayote in Mexico and worldwide.