Isolation and Characterization of a Yellow Xanthophyll Pigment-Producing Marine Bacterium, Erythrobacter sp. SDW2 Strain, in Coastal Seawater

Xanthophylls, a yellow pigment belonging to the carotenoid family, have attracted much attention for industrial applications due to their versatile nature. We report the isolation of a homo xanthophyll pigment-producing marine bacterium, identified as the Erythrobacter sp. SDW2 strain, from coastal seawater. The isolated Erythrobacter sp. SDW2 strain can produce 263 ± 12.9 mg/L (89.7 ± 5.4 mg/g dry cell weight) of yellow xanthophyll pigment from 5 g/L of glucose. Moreover, the xanthophyll pigment produced by the SDW2 strain exhibits remarkable antioxidative activities, confirmed by the DPPH (73.4 ± 1.4%) and ABTS (84.9 ± 0.7%) assays. These results suggest that the yellow xanthophyll pigment-producing Erythrobacter sp. SDW2 strain could be a promising industrial microorganism for producing marine-derived bioactive compounds with potential for foods, cosmetics, and pharmaceuticals.

Hydroxyl Safflower Yellow Pigment A (HSYA) Improves Vascular Endothelial Injury Induced by Lipopolysaccharide In Vitro Study

Aim: This research was to investigate the effects and mechanisms of HSYA in vascular endothelial injury by vitro study. Methods: Dividing HUVECs as Normal Control (NC), Model (LPS treated) group, HSYA-L, HSYA-M and HSYA-H groups. Cells in the HSYA treatment groups were treated with LPS, followed by 40 mg/ml, 80 mg/ml, and 120 mg/ml HSYA intervention (HSYA-L, HSYA-M, and HSYA -H groups), respectively. Measuring the cell proliferation, apoptosis, relative proteins and mRNA (TLR4, MyD88 and NF-κB(p65)) expressions by MTT, Flow cytometry, WB and RT-qPCR assay. Using cellular immunofluorescence to evaluate NF-κB(p65) nuclear volume of difference groups. Results: With HSYA supplement, the cell proliferation rates were significantly up-regulation with cell apoptosis significantly down-regulation with TLR4 relatived mRNA and proteins and NF-κB(p65) nuclear significantly depressed with dose-dependent (P <0.05, respectively). Conclusion: HSYA improved vascular endothelial injury induced by LPS via TLR4 pathway In Vitro.

Comparative Analysis of Flavonoid Metabolites in Foxtail Millet (Setaria italica) with Different Eating Quality

Foxtail millet (Setaria italica) is an important minor cereal crop in China. The yellow color of the de-husked grain is the most direct aspect for evaluating the foxtail millet quality. The yellow pigment mainly includes carotenoids (lutein and zeaxanthin) and flavonoids. To reveal the diversity and specificity of flavonoids in foxtail millet, we chose three high eating quality and two poor eating quality varieties as research materials. A total of 116 flavonoid metabolites were identified based on Ultra Performance Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry (UPLC-ESI-MS/MS) system. The tested varieties contained similar levels of flavonoid metabolites, but with each variety accumulating its unique flavonoid metabolites. A total of 33 flavonoid metabolites were identified as significantly discrepant between high eating quality and poor eating quality varieties, which were mainly in the flavonoid biosynthesis pathway and one of its branches, the flavone and flavonol biosynthesis pathway. These results showed the diversified components of flavonoids accumulated in foxtail millets and laid the foundation for further research on flavonoids and the breeding for high-quality foxtail millet varieties.

A Homeodomain-Containing Transcriptional Factor PoHtf1 Regulated the Development and Cellulase Expression in Penicillium oxalicum

Homeodomain-containing transcription factors (Htfs) play important roles in animals, fungi, and plants during some developmental processes. Here, a homeodomain-containing transcription factor PoHtf1 was functionally characterized in the cellulase-producing fungi Penicillium oxalicum 114-2. PoHtf1 was shown to participate in colony growth and conidiation through regulating the expression of its downstream transcription factor BrlA, the key regulator of conidiation in P. oxalicum 114-2. Additionally, PoHtf1 inhibited the expression of the major cellulase genes by coordinated regulation of cellulolytic regulators CreA, AmyR, ClrB, and XlnR. Furthermore, transcriptome analysis showed that PoHtf1 participated in the secondary metabolism including the pathway synthesizing conidial yellow pigment. These data show that PoHtf1 mediates the complex transcriptional-regulatory network cascade between developmental processes and cellulolytic gene expression in P. oxalicum 114-2. Our results should assist the development of strategies for the metabolic engineering of mutants for applications in the enzymatic hydrolysis for biochemical production.

Multidrug Resistance Behaviors of Clinical Pseudomonas aeruginosa Strains Associated to Pigment Coloration

Pseudomonas aeruginosa is an adaptable bacterial pathogen that infects various organs, including the respiratory tract, vascular system, urinary tract, and central nervous system leading to high morbidity and mortality. Our primary focus of this study was to characterize P. aeruginosa clinical strains on the basis of pigment color production, determine its association to multidrug resistance behavior and ability to form biofilm. We identified yellow (30.1%), green (39.8%) and no pigment (30.1%) producing strains from a total of 143 clinical isolates. Yellow pigment producing strains presented significant resistance to a class of antibiotics including &beta;-lactam (91.5%), aminoglycosides (70.5%), and carbapenems (51.9%) compared to green and non-pigmented strains. Importantly, 16.3% of yellow pigment producing strains was resistant to colistin where only 2.3% of non-pigmented and 1.8% of green pigmented strains were resistant to this agent. Moreover, yellow pigment producing strain were frequent producers of &beta;-lactamase group of enzymes, ESBL (55.6%), MBL (55.6%), and AmpC (50%) and displayed higher frequency of efflux positive group (64.2%) compared to green (7.14%) and non-pigmented one (28.5%). Notably, green pigment producing strains when compared to non-pigmented groups also displayed antibiotic susceptibility behavior similar to yellow pigment producing strains. Although yellow pigment producing strains were strong biofilm producers, no significant association was identified between pigment and biofilm formation. Among pigmented and non-pigmented strains, majority of yellow pigment producing strains have shown MIC levels greater than the green and non-pigmented strains. Our study has demonstrated the impact of pigment coloration on susceptibility to antimicrobial agents where yellow pigment producing strains represent considerably a serious problem as due to lack of alternative agents against such transformed strain may collectively be associated with multidrug resistance development.