Purple Pigment Research Articles

Characterization of plant-based meat alternatives blended with anthocyanins, chlorophyll, and various edible natural pigments

ABSTRACT The objective of this study was to characterize the physicochemical, proximal, textural, and visual properties of plant-based meat (PBM) patties blended with natural pigments such as anthocyanin from black beans, Fe-chlorophyll from spinach, and edible red and purple pigments. A comparison was made between these plant-based pigments and the pigments derived from animal-based sources (control). The values of the color coordinates of the developed patties were broadly distributed (L* [lightness], a* [redness], and b* [yellowness] of raw PBMs: 34–53, 2–25, and 4–27; steamed: 29–42, 4–21, and 5–25; and cooked: 28–43, 5–19, and 9–21, respectively). The proximate chemical analysis revealed no (P > .05) significant difference between the PBMs and the control in terms of moisture (63.28–61.25), crude protein (20.98–19.17) crude fat (3.19–2.92) and ash content (3.80–1.71). Nevertheless, significant differences (P < .05) were observed in textural attributes among all samples (S1-S16) in terms of hardness, chewiness, and gumminess. For instance, hardness (6.39–3.72), chewiness (9.27–4.13), and gumminess (3.04–1.60). Conversely, springiness showed considerable variations (P < .05) in a majority of PBM samples except for S1 (dilute red) (3.06) and S4 (paprika) (3.06) than control (3.31). For DPPH radical scavenging activity of patties samples incorporated with, the S10 (Red Cabbage) (19.95), S13 (Grape skin Color) (24.35), S15 (Anthocyanin) (33.12), and S16 (Fe-pheophytin) (18.69) of PBMs had significantly higher activity (P < .05) than the control (5.14). To sum up, the inclusion of natural pigments in PBM resulted in improved overall properties without any deleterious effects.

Covalent Bond between the Lys-255 Residue and the Main Chain Is Responsible for Stable Retinal Chromophore Binding and Sodium-Pumping Activity of Krokinobacter Rhodopsin 2.

Microbial rhodopsins are light-receptive proteins with various functions triggered by the photoisomerization of the retinal chromophore from the all-trans to 13-cis configuration. A retinal chromophore is covalently bound to a lysine residue in the middle of the seventh transmembrane helix via a protonated Schiff base. Bacteriorhodopsin (BR) variants lacking a covalent bond between the side chain of Lys-216 and the main chain formed purple pigments and exhibited a proton-pumping function. Therefore, the covalent bond linking the lysine residue and the protein backbone is not considered a prerequisite for microbial rhodopsin function. To further examine this hypothesis regarding the role of the covalent bond at the lysine side chain for rhodopsin functions, we investigated K255G and K255A variants of sodium-pumping rhodopsin, Krokinobacter rhodopsin 2 (KR2), with an alkylamine retinal Schiff base (prepared by mixing ethyl- or n-propylamine and retinal (EtSB or nPrSB)). The KR2 K255G variant incorporated nPrSB and EtSB as similarly to the BR variants, whereas the K255A variant did not incorporate these alkylamine Schiff bases. The absorption maximum of K255G + nPrSB was 524-516 nm, which was close to the 526 nm absorption maximum of the wild-type + all-trans retinal (ATR). However, the K255G + nPrSB did not exhibit any ion transport activity. Since the KR2 K255G variant easily released nPrSB during light illumination and did not form an O intermediate, we concluded that a covalent bond at Lys-255 is important for the stable binding of the retinal chromophore and formation of an O intermediate to achieve light-driven Na+ pump function in KR2.

A combined diagnostic approach for the investigation of lesions resembling aspergillosis in Caribbean sea fans (Gorgonia spp.).

Aspergillosis of gorgonian sea fans is a Caribbean-wide disease characterized by focal, annular purple pigmentation with central tissue loss. We applied a holistic diagnostic approach including histopathology and a combination of culture and direct molecular identification of fungi to evaluate these lesions with the goal of determining the diversity of associated micro-organisms and pathology. Biopsies were collected from 14 sea fans without gross lesions and 44 sea fans with lesions grossly consistent with aspergillosis in shallow fringing reefs of St. Kitts. Histologically, the tissue loss margin had exposure of the axis and amoebocyte encapsulation with abundant mixed micro-organisms. Polyp loss, gastrodermal necrosis, and coenenchymal amoebocytosis were at the lesion interface (purpled area transitioning to grossly normal tissue) with algae (n = 21), fungus-like hyphae (n = 20), ciliate protists (n = 16), cyanobacteria (n = 15), labyrinthulomycetes (n = 5), or no micro-organisms (n = 8). Slender, septate hyaline hyphae predominated over other morphological categories, but were confined to the axis with little host response other than periaxial melanization. Hyphae were absent in 6 lesioned sea fans and present in 5 control biopsies, questioning their pathogenicity and necessary role in lesion causation. From cultivation, different fungi were isolated and identified by sequencing of the nuclear ribosomal internal transcribed spacer region. In addition, 2 primer pairs were used in a nested format to increase the sensitivity for direct amplification and identification of fungi from lesions, thereby circumventing cultivation. Results suggest mixed and opportunistic infections in sea fans with these lesions, requiring longitudinal or experimental studies to better determine the pathogenesis.

A Simple Characterisation of Violacein Compound Derived from Chromobacterium sp. strain Dyh27s2016 and its Antimicrobial Activity Against Pseudomonas aeruginosa

Chromobacterium sp. strain Dyh27s2016 was isolated from the lake at Manipal International University. Its purple pigmented violacein is hypothesised for a broad spectrum of intriguing biological properties, specifically as an antibacterial agent against Gram-negative bacteria. Hence, the current study aimed to isolate, characterise, and review the antimicrobial property of violacein from the Dyh27s2016 strain against P. aeruginosa. The bacterial strain was cultured in nutrient broth with L-tryptophan (0.1 mg/ml); after 24 h, the bacteria were lysed with methanol (3:1 ratio) and mixed with ethyl acetate (4:1 ratio). The top layer was then separated to obtain a concentrated purple pigment. The pH was changed at varying ranges and measured with UV/Vis to characterize this pigment. Then the antimicrobial test was performed against P. aeruginosa using the microdilution method and gauged its minimal inhibitory concentration (MIC). Violacein pigment derived from Chromobacterium violacein was used as a control in all experiments. For the result, crude violacein from Chromobacterium sp. strain Dyh27s2016 was obtained, and the purple pigment in different pH was observed in varying colours; the compound was particularly decolourised at a highly alkaline solution. The pigment was also able to significantly inhibit the growth of P. aeruginosa from 200 µg/mL - 800 µg/mL. Tests show that this pigment has a maximum absorption of light wavelength at approximately 600 nm and antibiotic test results show that the pigment can be considered a potential antimicrobial drug against P. aeruginosa.

Chromatographic Characterization of Archaeological Molluskan Colorants via the Di-Mono Index and Ternary Diagram

One of the main research questions regarding archaeological molluscan purple pigments and dyes is whether it is possible to determine which malacological species produced these colorants. For this determination of the zoological provenance of the pigment, a multicomponent analysis must be performed, which can only be obtained from the HPLC technique—the optimal method for identifying all the detectable colorants in a sample. In order to find any trends in the compositions of the dye components from various species of purple-producing sea snails, a statistical formulation is needed. Though principal component analysis (PCA) is a powerful statistical tool that has been used in the analysis of these components, it is based on an algorithm that combines all the componential values and produces new two-dimensional parameters whereby the individualities of the original dye component values are lost. To maintain the integrity of the dye compositions in the purple pigments, a very simple formulation was first published in 2008 and applied to a limited number of samples. This property is known as DMI (short for Di-Mono Index), and for each sample, it is simply the ratio of the peak area of DBI relative to that of MBI, evaluated at the standard wavelength of 288 nm, which has been used for such peak calculations. Currently, considerably more modern and archaeological pigments have been analyzed via HPLC; thus, in the current study, the DMI has been expanded to characterize these purple pigments. Furthermore, a ternary diagram comprising the blue, violet, and red components that can be found in purple colorants is presented for both modern and archaeological purple pigments from the three Muricidae species known in antiquity to produce purple pigments. This triangular diagram is intuitive, retains the integrity of the original dyes, and is presented here for the first time. Both the DMI and the ternary diagram can discern whether a Hexaplex trunculus species or perhaps the Bolinus brandaris or Stramonita haemastoma species were used to produce the pigment. Further, these two representations can also determine whether the IND-rich or the DBI-rich varieties, or both, of H. trunculus were used to produce the purple pigment, either as a paint pigment or as a textile dye.

Pigmentation and Genotype Effects, Phenotypic Stability for Anthocyanins, Phenolic Compounds and Antioxidant Activity in the Corn Tassel

The tassels of corn can be utilized as a co-product for the production of phytochemicals. The objectives were to assess the impact of pigmentation and genotype on the levels of anthocyanins, phenolic compounds and antioxidant activity, and to determine the phenotypic stability of these traits. Sixteen genotypes were evaluated at two locations over two seasons. Corn genotypes in purple or pink pigmentation group had higher anthocyanin concentration and DPPH radical scavenging activity in tassel than those in normal green group. Tassel color can be used as a selection criterion to improve anthocyanin and antioxidant activity, but the trait is not effective to predict the phenolic concentration in the tassel. Genotype is an important source of variation for all parameters. The sensitivity of corn genotypes with high levels of measured compounds to the environment indicates the importance of choosing suitable locations and seasons for the production of high-quality corn tassels as a co-product of grain and vegetable corn. The findings of this study can be valuable for producers who intend to select genotypes for phytochemical production in corn tassels, as well as to corn breeders who aim to develop improved varieties with high yield and high bioactive phytochemicals in tassel.

Organic-Inorganic Hybrid Pigments Based on Bentonite: Strategies to Stabilize the Quinoidal Base Form of Anthocyanin.

Anthocyanins are one of the natural pigments that humanity has employed the most and can substitute synthetic food dyes, which are considered toxic. They are responsible for most purple, blue, and red pigment nuances in tubers, fruits, and flowers. However, they have some limitations in light, pH, oxygen, and temperature conditions. Combining biomolecules and inorganic materials such as clay minerals can help to reverse these limitations. The present work aims to produce materials obtained using cetyltrimethylammonium bromide in bentonite clay for incorporation and photostabilization of anthocyanin dye. Characterizations showed that the organic molecules were intercalated between the clay mineral layers, and the dye was successfully incorporated at a different pH. Visible light-driven photostability tests were performed with 200 h of irradiation, confirming that the organic-inorganic matrices were efficient enough to stabilize the quinoidal base form of anthocyanin. The pigment prepared at pH 10 was three-fold more stable than pH 4, showing that the increase in the synthesis pH promotes more stable colors, probably due to the stronger intermolecular interaction obtained under these conditions. Therefore, organobentonite hybrids allow to stabilize the fragile color coming from the quinoidal base form of anthocyanin dyes.

Differences in the content of purple pigments, catechinopyranocyanidins A and B, in various adzuki beans, Vigna angularis.

Catechinopyranocyanidins A and B (cpcA, B) are purple pigments isolated from the seed coat of the small red bean called adzuki in Japanese (Vigna angularis). CpcA and B are known to be responsible for the purple color of an-paste. The quality evaluation of the paste is based on its purple color; therefore, it is important to analyze the contents of cpcA and B in various azuki beans, which differ in the cultivar, production area, and cultivation conditions. The extraction of cpcA and B from dried beans was conducted, followed by high-performance liquid chromatography analysis. The content of cpcA and B in various cultivars from Japan, Korea, China, and Nepal was quantified. The cpcA and B content was the highest in the regular adzuki cultivar from Hokkaido Prefecture (Japan), and that of the beans from Korea and China was low. The content of the pale-colored beans from Nepal was the lowest.

Nitrogen Enriched Solid-State Cultivation for the Overproduction of Azaphilone Red Pigments by Penicillium sclerotiorum SNB-CN111

Azaphilones are microbial specialized metabolites employed as yellow, orange, red or purple pigments. In particular, yellow azaphilones react spontaneously with functionalized nitrogen groups, leading to red azaphilones. In this study, a new two-step solid-state cultivation process to produce specific red azaphilones pigments was implemented, and their chemical diversity was explored based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and a molecular network. This two-step procedure first implies a cellophane membrane allowing accumulating yellow and orange azaphilones from a Penicillium sclerotiorum SNB-CN111 strain, and second involves the incorporation of the desired functionalized nitrogen by shifting the culture medium. The potential of this solid-state cultivation method was finally demonstrated by overproducing an azaphilone with a propargylamine side chain, representing 16% of the metabolic crude extract mass.

First Report of Leaf Spot Disease on Chamaedorea elegans Caused by Fusarium oxysporum in China.

Chamaedorea elegans, native to Mexico and Guatemala, is a commonly planted indoor and small-scale garden ornamental due to its stately appearance, tolerance of low light levels, and its ability to improve air quality (El-Khateeb et al. 2010). In December 2021, an unknow leaf-spot disease was observed on C. elegans in Ganzhou City of Jiangxi Province, China (25.83 °N, 114.93 °E). The symptoms were small brown spots on the leaves, gradually expanded into irregular dark brown spots with necrotic tissue forming in the center of the lesions (Figure 2 A-1 and A-2). To isolate the pathogen, the diseased leaves were surface sterilized in 75% ethanol for 30 s. Small pieces of tissue (5 × 5 mm) were taken from the margin between diseased and healthy tissue, disinfected 1% NaClO for 45 s, washed three times in sterile water, and then placed on PDA at 25 ± 1°C for 5 days. Later, five isolates were purified from single spores and each of the five isolates has the same properties as described below. The isolates had abundant pale purple flocculent hyphae with purple pigmentation (Figure 2 C-1 and C-2). Macroconidia were falciform, straight or slightly curved, 1-2 septate, 11.75 to 22.99 × 3.06 to 4.44 μm (μ=16.08 μm × 3.37 μm, n=50) (Figure 2 D-1). Microconidia were oval or elliptical, a septate, 4.03 to 9.19 × 1.92 to 3.73 μm (μ=5.88 μm × 2.66 μm, n=50) (Figure 2 D-2). Chlamydospores formed singly or in pairs, and were terminal or intercalary in hyphae (Figure 2 D-3). Based on morphological characteristics, the fungus was preliminarily identified as a Fusarium sp. (Leslie et al. 2006). To confirm the identification, primers ITS1/ITS4 (White et al. 1990), RPB2-5f2/RPB2-7cr (O'Donnell et al. 2010; Liu et al. 1999) and TEF 1-αF/TEF 1-αR (O'Donnell et al. 2000) were used to amplify and sequence apportion of the ITS, RPB2 and TEF (Table 1). The sequences (Genebank accession number: OM780148, OM782679, OM782680) shared 100% idnetity with Fusarium oxysporum (Genebank accession number: MH866024.1, MH484930.1, MH485021.1). The maximum likelihood (ML) phylogenetic analysis of the concantenated ITS, RPB2 and TEF sequences was performed in MEGA7.0. (Sudhir et al. 2016), assigning the isoaltes to the F. oxysporum species complex (Figure 1). To confirm the pathogenicity, nine pots of healthy 3-year-old C. elegans plants were inoculated in the greenhouse (12 h light/12 h dark cycle, RH 90 %, three for wounded inoculation, three for nonwounded inoculation and three for control). Fifty disinfected leaves were wounded with sterile needles and fifty remained unwounded. The wounded (Figure 2 B-1 and B-2) and unwounded leaves were inoculated with a 10 μL spore suspension (1.0 × 106 conidia/ml) which was taken from each of the five isolates cultured for 7 days. Fifty leaves were mock-inoculated with sterile water (Figure 2 B-3 and B-4). After incubation for 7 days, the wounded leaves inoculated with the spore suspension had similar symptoms to the original diseased leaves, while the unwounded leaves and the control leaves did not develop symptoms. The experiment was repeated three times and the pathogens was reisolated from wound-inoculated leaves with the same morphological characteristics to the original pathogens, and identified as F. oxysporum by morphological and molecular analysis, completing Koch's postulates. F. oxysporum, a pathogen with a broad spectrum of hosts, ranks 5th among the top 10 fungal plant pathogens (Amjad et al. 2018.) and has been reported to Carpinus betulus, Citrullus lanatus, Pinus pinea (Mao et al. 2021; Muhammad et al. 2021; Monther et al. 2021). To our knowledge, this is the first report of leaf spot disease on C. elegans caused by F. oxysporum in China. C. elegans is an important ornamental plant in China with high economic value, so the disease has the potential to be a threat to its cultivation industry.

A formulation design and preparation of gold‐free purple of Cassius based on the doped malayaite

AbstractMalayaite (CaSnSiO5) doped with Cr may be used as a cheap gold‐free purple red pigment to substitute the purple of Cassius. Different molar ratios of Ca/Sn malayaite doped with Cr were prepared and various characrizations were employed. The results indicate that the pigment is composed of CaSnSiO5 and SnO2 when the molar ratio of Ca/Sn is 0.8, and the color is close to agate red color. When the molar ratio of Ca/Sn is 1.25, the phases CaSnSiO5, SnO2, and Ca3SnSi2O9 exist simultaneously, while the color is yellow or yellowish colors. Excessive Ca(II) increases the normal calcination temperature of pigment, from 1080°C to 1130°C. The distribution of chromium ions on the sample surface varies greatly with the change in Ca/Sn molar ratio. The theoretical formulation was obtained based on the stoichiometric formula of CaCrxSn1–xSiO5 by using response surface methodology (RSM). According to the RSM model, the relationship between the molar ratio of Cr/Sn/Ca and the color property was established. The desired pigment formulation (rendering agate red) color is that the molar ratio of Cr/Sn/Ca is 0.010:1.003:0.800. The accuracy of the models was confirmed with analysis of variance, the simulation results were verified again by experiments.

Fusarium species in maize grains and stems (Zea mays L.) from subsistence and commercial systems

The objective of this research was the morphomolecular identification of species of the genus Fusarium associated with native and commercial maize genotypes in municipalities of Puebla and Morelos, Mexico, as well as to describe the socioeconomic and cultural importance of maize cultivation. Fusarium species were isolated from grains and stem cuttings with purple, brown, and dark brown pigmentations. They were identified morphomolecularly by using taxonomic keys and the Dinocapture 2.0 software, and by DNA extraction by the CTAB method and amplification of the ITS1 and ITS4 region by PCR. Four species were identified: Fusarium equiseti, Fusarium verticillioides, Fusarium incarnatum and Fusarium napiforme with an identity greater than 98%. The genotypes with the highest incidence of Fusarium spp. were: Pioneer 30F35 in San Miguel, Teotlalco, Puebla by F. verticillioides (A2). The genotypes with the lowest incidence were: Shark from Tetelilla, Morelos by F. incarnatum (A1), F. verticillioides (A6) and F. napiforme (A7). Maize is the main food in many locations in Mexico, however, due to the high consumption of this grain and its derivatives, as well as the high consumption of meat presumably fed with this grain, it could represent a route of ingestion of mycotoxins.

Chamaesiphon fontinalis sp. nov., a new species of unicellular asymmetrically dividing cyanobacteria

Extensive brownish biofilms of algal-bacterial communities were found on stones in streams in the Valdaysky National Park (Russia). The dominant unicellular cyanobacteria in biofilms was determined as Chamaesiphon sp. Although species of this genus often occur in the periphyton of fast-flowing waters, many of them have a geographically limited distribution and occur mainly in mountain streams and rivers in Europe. The strain Chamaesiphon sp. CALU 1864 was isolated from epilithic biofilms in the spring Tekunok. We found that it differs from previously described species not only by its unusual purple pigmentation, but also by morphological features. Molecular-genetic analysis of the primary 16S rRNA sequence and secondary structures of the internal transcribed spacer of the ribosomal operon also confirmed its uniqueness. Phylogenetically, the strain represents an independent lineage on the evolutionary tree. Based on the differences found, which provide strong support for its delineation, we propose to consider strain CALU 1864 as a new species, Chamaesiphon fontinalis sp. nov., first discovered in Russia and described in accordance with the current rules of the International Code of Nomenclature for Algae, Fungi and Plants.

Inheritance studies on different quantitative and qualitative fruit traits in brinjal (Solanum melongena L.)

Generation mean analysis of brinjal lines, GL 401 × BR 104 (CROSS I), GL 401 × W 230 (CROSS II) and W 230 × RMO 1142 (CROSS III) six generation of three crosses viz. highlighted the involvement of epistatic interactions (duplicate) for most of the qualitative traits. However, the number of fruits per plant in CROSS I &amp; III and fruit girth, calyx length, and yield per plant in CROSS II confirmed the occurrence of complementary epistasis. Mainly, additive effect for fruit girth, non-additive effect for calyx length, calyx width, peduncle girth, fruit weight, and fruit length, and both types for peduncle length, number of fruits /cluster, number of fruits/ plant, and yield/ plant were experienced. Additive × dominance or dominance × dominance type of interactions were more prevalent than additive × additive type of interactions for different traits. Cluster bearing was monogenic dominant and green color of calyx as well as peduncle was dominant over purple with the duplicate type of epistasis. Fruit shape was dgenic with incomplete dominance. Fruit color displayed digenic control in CROSS I &amp; II and tri-genic ratio in CROSS III with incomplete dominance of purple and green pigmentations producing variable color intensity in homozygous or heterozygous conditions.

Food-Grade Bacteria Combat Pathogens by Blocking AHL-Mediated Quorum Sensing and Biofilm Formation.

Disrupting bacterial quorum sensing (QS) signaling is a promising strategy to combat pathogenic biofilms without the development of antibiotic resistance. Here, we report that food-associated bacteria can interfere with the biofilm formation of a Gram-negative pathogenic bacterium by targeting its AHL (acyl-homoserine lactone) QS system. This was demonstrated by screening metabolic end-products of different lactobacilli and propionibacteria using Gram-negative and biofilm-forming Chromobacterium violaceum as the QS reporter and our anti-QS microscale screening platform with necessary modifications. The method was optimized in terms of the inoculation technique and the concentrations of D-glucose and L-tryptophan, two key factors controlling the synthesis of violacein, a purple pigment indicating the activation of the QS system in C. violaceum. These improvements resulted in ca. 16-times higher violacein yields and enabled revealing anti-QS effects of Lactobacillus acidophilus, Lentilactobacillus kefiri, Lacticaseibacillus rhamnosus and Propionibacterium freudenreichii, including new cheese-associated strains. Our findings also suggest that acetate and propionate excreted by these species are the main factors that interrupt the QS-mediated signaling and subsequent biofilm growth without affecting the cell viability of the C. violaceum reporter. Thus, the present study reports a revised anti-QS screening method to accurately define new bacteria with an ability to combat pathogens in a safe and sustainable way.

Genetic Diversity of Black Amaranth (Amaranthus quitensis Kunth) Landraces of Ecuadorian Highlands: Association Genotypes—Color Morphotypes

Black amaranth (Amarantus quitensis Kunth) is an ancestral crop of the Ecuadorian Andean region, where traditionally it is called ataco or sangorache. Nowadays, there is some information about the phenotypic diversity of black amaranth landraces, but there are no data about their genetic diversity. In this study, we evaluated the genetic diversity of 139 black amaranth accessions collected twice (1981–1986 and 2014–2015) in three representative Ecuadorian Andean provinces for this crop (Imbabura, Tungurahua, and Cañar) using nine simple sequence repeats (SSR) markers. We detected low genetic diversity levels; only a total of 36 alleles were amplified in 139 accessions, with a mean allelic richness of 4.0 per marker, observed heterozygosity of 0.014, expected heterozygosity of 0.134, and Shannon’s information index of 0.297. In addition, only 17 genotypes were found, with a predominant genotype (83.6%) and up to 12 accession-unique genotypes. Moreover, a certain genetic diversity decrease was observed over the last decades, especially in Tungurahua and Cañar, where today practically only the predominant genotype exists. The ataco germplasm is genetically structured into two well-defined genotype clusters and could constitute two different genetic lineages. Furthermore, a clear association of each genotype group with a different color morphotype defined in a previous agromorphological characterization was observed. The accessions of the majority group of genotypes showed purple pigmentation in stems, leaves, and inflorescences, whereas those of the other genotype group showed less intense pigmentation (pink stems, inflorescences, and green leaves). Molecular information obtained in this study may be useful for the suitable management and conservation of this underutilized genetic plant resource that is of great food and cultural significance for indigenous farming communities of the Ecuadorian highlands.

Transcriptomic analyses provide new insights into green and purple color pigmentation in Rheum tanguticum medicinal plants.

Rheum tanguticum Maxim. ex Balf is a traditional Chinese medicinal plant that is commonly used to treat many ailments. It belongs to the Polygonacae family and grows in northwest and southwest China. At high elevations, the color of the plant's young leaves is purple, which gradually changes to green during the growth cycle. Anthraquinone, which is known for various biological activities, is the main bioactive compound in R. tanguticum. Although a significant amount of research has been done on R. tanguticum in the past, the lack of transcriptome data limits our knowledge of the gene regulatory networks involved in pigmentation and in the metabolism of bioactive compounds in Rheum species. To fill this knowledge gap, we generated high-quality RNA-seq data and performed multi-tissue transcriptomic analyses of R. tanguticum. We found that three chlorophyll degradation enzymes (RtPPH, RtPao and RtRCCR) were highly expressed in purple samples, which suggests that the purple pigmentation is mainly due to the effects of chlorophyll degradation. Overall, these data may aid in drafting the transcriptional network in the regulation and biosynthesis of medicinally active compounds in the future.

Phenotypic plasticity and characterization of Chromobacterium isolates from aquatic environment

The genus Chromobacterium spp. are gram-negative bacilli, which may or may not have characteristic purple pigmentation, and are mainly isolated from soil, water and infected patients. The main representative species of this genus is C. violaceum, responsible for a high mortality rate among those infected. The aim of this study was to genetically characterize and broadly compare phenotypic characteristics between the genus Chromobacterium species described in the literatureand bacterial isolates. This study is an experimental research, in which sequencing and phenotypic tests of bacterial isolates were carried out for comparison with species of the genus Chromobacterium. Two strains were identified, CRJL01 and CRJL02 that have characteristics of Chromobacterium spp species. These isolates showed high resistance to antibiotics, tolerance and resistance to metals, biochemical and physiological versatility of the CRJL01 and CRJL02 strains. In the sequencing of the 16S rRNA gene, the CRJL01 strain showed similarity with the C. piscinae strain. The CRJL02 strain showed similarity with the C. subtsugae strain. This work is the first report in 40 years of Chromobacterium spp. in the Brazilian Midwest – Goiás, in water samples. This isolated genus has a wide applicability for the pharmaceutical, food and cosmetic industries, due to the production of its purple/violet pigment known as violacein, and its bioprospecting is of great importance. Thus, this study is a kick-off for exploring your produced pigment.

Perceptions of Power: Purple in Archaic Greek, Ancient Mesopotamian Inscriptions, and the Hebrew Bible

Purple in the ancient world held common characteristics: symbolic of power, wealth, and beneficence. Purple was also thought to be produced and imported from the Phoenician area, situated along the Levantine coastal shore. Yet between different literature circles, the specifics of purple diverged widely. This article explores the social function of purple-material (and its inherent purple-colour) in the Hebrew Bible in light of wider ancient Near East and eastern Mediterranean texts. As with any given cultural material, the meaning of purple is relative; it is differentially significant according to audience, context, subject matter, and the qualities of the material. By utilising a sociological and comparative approach, in the following I consider the use of purple in Homeric epic, ancient Mesopotamian inscriptions and biblical texts. I demonstrate that purple pigments and dyes, as well as the purple-colour of the object to which the pigments/dyes is applied, is a key means to communicate something culturally-specific. In so doing, this ultimately provides fresh insight into the texts and offers a glimpse into the thought processes of ancient society.

A Mutation in the MYBL2-1 Gene Is Associated with Purple Pigmentation in Brassica oleracea.

Anthocyanins are well-known antioxidants that are beneficial for plants and consumers. Dihydroflavonol-4-reductase (DFR) is a key gene of anthocyanin biosynthesis, controlled by multiple transcription factors. Its expression can be enhanced by mutations in the negative regulator of anthocyanin biosynthesis myeloblastosis family transcription factor-like 2 (MYBL2). The expression profiles of the DFR gene were examined in 43 purple and green varieties of Brassica oleracea L., Brassica napus L., Brassica juncea L., and Brassica rapa L. MYBL2 gene expression was significantly reduced in purple varieties of B. oleracea, and green varieties of B. juncea. The MYBL2 gene sequences were screened for mutations that can affect pigmentation. Expression of the DFR gene was cultivar-specific, but in general it correlated with anthocyanin content and was higher in purple plants. Two single nucleotide polymorphysms (SNPs) were found at the beginning of the DNA-binding domain of MYBL2 gene in all purple varieties of B. oleracea. This mutation, leading to an amino acid substitution and the formation of a mononucleotide repeat (A)8, significantly affects RNA structure. No other noteworthy mutations were found in the MYBL2 gene in green varieties of B. oleracea and other studied species. These results bring new insights into the regulation of anthocyanin biosynthesis in genus Brassica and provide opportunities for generation of new purple varieties with precise mutations introduced via genetic engineering and CRISPR/Cas.