Immunohistochemical expression of Fibrillin-1 in idiopathic epiretinal membranes.

PURPOSE: To investigate the expression patterns of Fibrillin-1 in idiopathic epiretinal membranes (iERM) and identify Fibrillin-1-secreting cells. METHODS: iERM samples were collected via standard 27-gauge vitrectomy and subsequently subjected to flat-mount immunohistochemistry with double staining for the following markers: Fibrillin-1, glial acidic fibrillary protein (GFAP), cellular retinaldehyde-binding protein (CRALBP), retinoid isomerohydrolase RPE65 (RPE65), and α-smooth muscle actin (α-SMA). RESULTS: Fibrillin-1 was detected throughout the iERM. The colocalization of Fibrillin-1 with α-SMA, CRALBP, and RPE65 suggested that myofibroblasts and retinal pigment epithelial (RPE) cells secreted Fibrillin-1. The lack of colocalization between GFAP and Fibrillin-1 indicated that GFAP-positive glial cells did not secrete Fibrillin-1. The colocalization of CRALBP and RPE65 with α-SMA indicated the transformation of RPE cells into myofibroblasts. This suggested that RPE cells transformed into myofibroblasts and secreted Fibrillin-1. The lack of colocalization between GFAP and α-SMA implied that GFAP-positive glial cells did not express α-SMA. CONCLUSIONS: Fibrillin-1 is widely distributed in iERMs, and myofibroblasts were the primary sources of Fibrillin-1 secretion. Additionally, during their transformation into myofibroblasts, RPE cells secreted Fibrillin-1. GFAP-positive glial cells did not express α-SMA nor secrete Fibrillin-1. KEY MESSAGES: What is known Idiopathic epiretinal membranes are a common cause of visual acuity and quality impairment. The protein and cell components of idiopathic epiretinal membrane exhibit diversity. What is new Fibrillin-1 is present throughout the idiopathic epiretinal membrane. Myofibroblasts are the most important source of Fibrillin-1 secretion. Retinal pigment epithelial cells also secrete Fibrillin-1 when transforming into myofibroblast. Glial cells do not transform to myofibroblast and do not secrete Fibrillin-1.

Switching to Intravitreal Brolucizumab after Ranibizumab or Aflibercept Using Treat and Extend Regimen for Neovascular Age-Related Macular Degeneration in Japanese Patients: 1-Year Results and Factors Associated with Treatment Responsiveness.

Objective: To purpose of this study was to retrospectively evaluate the 1-year outcomes and factors associated with the treatment responsiveness of switching to intravitreal brolucizumab (IVBR) for neovascular age-related macular degeneration (nAMD) in Japanese patients refractory to ranibizumab or aflibercept using a treat and extend (TAE) regimen. Methods: A total of 48 eyes of 47 nAMD patients were switched to IVBR, and 36 eyes of 35 patients (27 males and 8 females) underwent 1-year treatment after the switch. Results: The rate of dry macula was significantly higher 12 months after the switch to IVBR (p < 0.001), with a significant decrease in the mean central macular thickness (CMT) and the mean central choroidal thickness (CCT) (p < 0.01 and p < 0.01, respectively). The injection interval was significantly extended from 7.0 ± 1.7 weeks to 10.3 ± 2.5 weeks 12 months after the switch (p < 0.001). In the multivariate analysis, a smaller number of prior anti-VEGF injections (p = 0.025; odds ratio: 0.947; 95% confidence interval: 0.903-0.994) and a pre-switching CCT of less than 250 µm (p = 0.023; odds ratio: 0.099; 95% confidence interval: 0.013-0.731) were associated with the good response group. Conclusions: These results suggest that IVBR may suppress disease activity and prolong the injection interval by switching for AMD patients with an insufficient response to treatment with ranibizumab and aflibercept.

One-Year Outcome of Intravitreal Injection of Ranibizumab Biosimilar for Myopic Choroidal Neovascularization in Japanese Patients.

Objectives: To evaluate the one-year outcomes of intravitreal ranibizumab biosimilar (RBZ-BS) injections for myopic choroidal neovascularization (mCNV) in Japanese patients. Methods: Twenty-one patients (mean age 69.0 years; 4 males, 17 females) with high myopia and mCNV were retrospectively reviewed. Twelve were treatment-naïve, and nine had previous anti-VEGF treatments. Efficacy measures included best-corrected visual acuity (BCVA) and central macular thickness (CMT). Results: The treatment-naïve group showed significant BCVA improvement from 0.55 ± 0.34 at baseline to 0.24 ± 0.28 at 12 months. The previously treated group had no significant BCVA changes. CMT significantly decreased in both groups: from 295.3 ± 105.2 µm to 207.3 ± 63.0 µm in the treatment-naïve group, and from 196.1 ± 62.0 µm to 147.2 ± 50.1 µm in the previously treated group. Dry macula rates were high: 83% at 3 months and 83% at 12 months in the treatment-naïve group, and 67% at 3 months and 89% at 12 months in the previously treated group. No adverse events were reported. Conclusions: These findings indicate that RBZ-BS is an effective and safe treatment for mCNV, particularly in treatment-naïve patients. The use of RBZ-BS offers a cost-effective alternative to original ranibizumab, reducing financial burdens while maintaining high therapeutic efficacy. Further studies with larger sample sizes and longer follow-up periods are needed to confirm these results and evaluate long-term outcomes and cost-effectiveness.

The impact of removing the epiretinal membrane and inner limiting membrane for sustained subretinal fluid by macular neovascularization refractory to anti-VEGF therapy.

Purpose: Anti-vascular endothelial growth factor (VEGF) therapy is the most prevalent intervention for exudative lesions secondary to neovascular age-related macular degeneration (nAMD) and other macular neovascularization (MNV). However, in some cases refractory to the latest anti-VEGF agents is associated with epiretinal membrane (ERM) or vitreomacular traction. We applied a vitrectomy to remove those pathologies which may be effective for reducing the exudation. Observations: In this case report, we present 2 cases with sustained subretinal fluid and macular neovascularization secondary to nAMD or dome-shaped macula that poorly responded to anti-VEGF therapy. In both cases, removing thin ERM or vitreomacular traction with an inner limiting membrane peeling promptly resolved the subretinal fluid and no recurrence was observed thereafter. Conclusions and importance: Vitrectomy could be an effective modality for anti-VEGF drug-resistant MNV cases with vitreomacular traction or ERM even in the anti-VEGF era.

Artificial intelligence-based differential diagnosis of orbital MALT lymphoma and IgG4 related ophthalmic disease using hematoxylin-eosin images.

PURPOSE: To investigate the possibility of distinguishing between IgG4-related ophthalmic disease (IgG4-ROD) and orbital MALT lymphoma using artificial intelligence (AI) and hematoxylin-eosin (HE) images. METHODS: After identifying a total of 127 patients from whom we were able to procure tissue blocks with IgG4-ROD and orbital MALT lymphoma, we performed histological and molecular genetic analyses, such as gene rearrangement. Subsequently, pathological HE images were collected from these patients followed by the cutting out of 10 different image patches from the HE image of each patient. A total of 970 image patches from the 97 patients were used to construct nine different models of deep learning, and the 300 image patches from the remaining 30 patients were used to evaluate the diagnostic performance of the models. Area under the curve (AUC) and accuracy (ACC) were used for the performance evaluation of the deep learning models. In addition, four ophthalmologists performed the binary classification between IgG4-ROD and orbital MALT lymphoma. RESULTS: EVA, which is a vision-centric foundation model to explore the limits of visual representation, was the best deep learning model among the nine models. The results of EVA were ACC = 73.3% and AUC = 0.807. The ACC of the four ophthalmologists ranged from 40 to 60%. CONCLUSIONS: It was possible to construct an AI software based on deep learning that was able to distinguish between IgG4-ROD and orbital MALT. This AI model may be useful as an initial screening tool to direct further ancillary investigations.

The hypothetical molecular mechanism of the ethnic variations in the manifestation of age-related macular degeneration; focuses on the functions of the most significant susceptibility genes.

Age-related macular degeneration (AMD) is the leading sight-threatening disease in developed countries. On the other hand, recent studies indicated an ethnic variation in the phenotype of AMD. For example, several reports demonstrated that the incidence of drusen in AMD patients is less in Asians compared to Caucasians though the reason has not been clarified yet. In the last decades, several genome association studies have disclosed many susceptible genes of AMD and revealed that the association strength of some genes was different among races and AMD phenotypes. In this review article, the essential findings of the clinical studies and genome association studies for the most significant genes CFH and ARMS2/HTRA1 in AMD of different races are summarized, and theoretical hypotheses about the molecular mechanisms underlying the ethnic variation in the AMD manifestation mainly focused on those genes between Caucasians and Asians are discussed.

Stromal area differences with epithelial-mesenchymal transition gene changes in conjunctival and orbital mucosa-associated lymphoid tissue lymphoma.

Purpose: To examine the molecular biological differences between conjunctival mucosa-associated lymphoid tissue (MALT) lymphoma and orbital MALT lymphoma in ocular adnexa lymphoma. Methods: Observational case series. A total of 129 consecutive, randomized cases of ocular adnexa MALT lymphoma diagnosed histopathologically between 2008 and 2020.Total RNA was extracted from formalin-fixed paraffin-embedded tissue from ocular adnexa MALT lymphoma, and RNA-sequencing was performed. Orbital MALT lymphoma gene expression was compared with that of conjunctival MALT lymphoma. Gene set (GS) analysis detecting for gene set cluster was performed in RNA-sequence. Related proteins were further examined by immunohistochemical staining. In addition, artificial segmentation image used to count stromal area in HE images. Results: GS analysis showed differences in expression in 29 GS types in primary orbital MALT lymphoma (N=5,5, FDR q-value <0.25). The GS with the greatest difference in expression was the GS of epithelial-mesenchymal transition (EMT). Based on this GS change, immunohistochemical staining was added using E-cadherin as an epithelial marker and vimentin as a mesenchymal marker for EMT. There was significant staining of vimentin in orbital lymphoma (P<0.01, N=129) and of E-cadherin in conjunctival lesions (P=0.023, N=129). Vimentin staining correlated with Ann Arbor staging (1 versus >1) independent of age and sex on multivariate analysis (P=0.004). Stroma area in tumor were significant difference(P<0.01). Conclusion: GS changes including EMT and stromal area in tumor were used to demonstrate the molecular biological differences between conjunctival MALT lymphoma and orbital MALT lymphoma in ocular adnexa lymphomas.

Relationship between vitreous interleukin-6 levels and vitreous particles findings on widefield optical coherence tomography in posterior uveitis.

PURPOSE: To investigate relationship between vitreous interleukin-6 levels and vitreous particles findings on widefield optical coherence tomography in posterior uveitis. METHODS: This retrospective study examined vitreous inflammatory cells (hyperreflective particles) of posterior uveitis on widefield optical coherence tomography (WOCT). We examined the number of hyperreflective particles (possibility of vitreous inflammatory cells) observed on WOCT and the correlations with interleukin-6 (IL-6) levels. The relationship between vitreous IL-6 levels and image findings from WOCT from 37 eyes (34 patients) with posterior uveitis were analyzed. Mean patient age was 63.4±15.7 years. (Mean± standard deviation) IL-6 concentration in vitreous humor was 79.9±7380.9 pg/mL Uveitis was infectious in 9 cases and non-infectious in 28 cases with multiplex polymerase chain reaction system. We measured the number and size of vitreous cells in the posterior vitreous, defined as the space between the upper vitreous and the internal limiting membrane on WOCT at the macular, upper, and lower regions. Image analysis software was also used for cell counting. RESULTS: A strong correlation was seen between human and software counts. Pearson's correlation coefficient (PCC) was performed to compare categorial variables (on macular +0.866; upper cavity +0.713; lower cavity +0.568; total vitreous cavity +0.834; P<0.001 each). IL-6 levels correlated with both vitreous cell counts and cell counts observed on macular WOCT (human-counted group +0.339, P = 0.04; software-counted group +0.349, P = 0.03). Infectious uveitis showed higher IL-6 levels (P = 0.016) and high cell counts compared with non-infectious uveitis (P = 0.04). CONCLUSIONS: Vitreous number of hyperreflective particles (cells) findings on WOCTcorrelated well with human and software cell counts. Vitreous cells findings on WOCT also correlated with IL-6 concentrations on macular.

Increased sodium fluorescein transport by corticosteroids is inhibited by a LAT-1 specific inhibitor in retinal pigment epithelial cells in vitro.

To investigate whether aldosterone (ALD) and hydrocortisone (HC) change the gene expression of SLC7A5, which encodes the large neutral amino acid transporter small subunit 1 (LAT1), and the transport activity of LAT1 in the retinal pigment epithelium (RPE) in vitro. ARPE-19 cells were grown to confluence. After withdrawing the serum, ALD or HC was added with several doses and incubated, and SLC7A5 gene expression was measured. The influx and efflux transport of sodium fluorescein (Na-F) were evaluated using the Transwell culture system. SLC7A5 gene expression was upregulated by ALD and downregulated by HC in a dose-dependent manner. Both ALD and HC significantly increased the influx and efflux Na-F transport of RPE cells at a dose that did not change the expression of SLC7A5. JPH203, a specific inhibitor of LAT1, significantly reduced accelerated Na-F transport. Both ALD and HC increased the gene expression of zonula occludin-1 (ZO-1) although they did not change the immunoreactivity of ZO-1 in RPE cells. LAT1 may play an important role in increasing Na-F transport associated with ALD and HC administration. A specific LAT1 inhibitor may effectively regulate the increased material transport of RPE induced by ALD and HC.

Astaxanthin: Past, Present, and Future.

Astaxanthin (AX), a lipid-soluble pigment belonging to the xanthophyll carotenoids family, has recently garnered significant attention due to its unique physical properties, biochemical attributes, and physiological effects. Originally recognized primarily for its role in imparting the characteristic red-pink color to various organisms, AX is currently experiencing a surge in interest and research. The growing body of literature in this field predominantly focuses on AXs distinctive bioactivities and properties. However, the potential of algae-derived AX as a solution to various global environmental and societal challenges that threaten life on our planet has not received extensive attention. Furthermore, the historical context and the role of AX in nature, as well as its significance in diverse cultures and traditional health practices, have not been comprehensively explored in previous works. This review article embarks on a comprehensive journey through the history leading up to the present, offering insights into the discovery of AX, its chemical and physical attributes, distribution in organisms, and biosynthesis. Additionally, it delves into the intricate realm of health benefits, biofunctional characteristics, and the current market status of AX. By encompassing these multifaceted aspects, this review aims to provide readers with a more profound understanding and a robust foundation for future scientific endeavors directed at addressing societal needs for sustainable nutritional and medicinal solutions. An updated summary of AXs health benefits, its present market status, and potential future applications are also included for a well-rounded perspective.

Machine Learning Model with Texture Analysis for Automatic Classification of Histopathological Images of Ocular Adnexal Mucosa-associated Lymphoid Tissue Lymphoma of Two Different Origins.

PURPOSE: The purpose of this study was to develop artificial intelligence algorithms that can distinguish between orbital and conjunctival mucosa-associated lymphoid tissue (MALT) lymphomas in pathological images. METHODS: Tissue blocks with residual MALT lymphoma and data from histological and flow cytometric studies and molecular genetic analyses such as gene rearrangement were procured for 129 patients treated between April 2008 and April 2020. We collected pathological hematoxylin and eosin-stained (HE) images of lymphoma from these patients and cropped 10 different image patches at a resolution of 2048 × 2048 from pathological images from each patient. A total of 990 images from 99 patients were used to create and evaluate machine-learning models. Each image patch of three different magnification rates at ×4, ×20, and ×40 underwent texture analysis to extract features, and then seven different machine-learning algorithms were applied to the results to create models. Cross-validation on a patient-by-patient basis was used to create and evaluate models, and then 300 images from the remaining 30 cases were used to evaluate the average accuracy rate. RESULTS: Ten-fold cross-validation using the support vector machine with linear kernel algorithm was identified as the best algorithm for discriminating between conjunctival mucosa-associated lymphoid tissue and orbital MALT lymphomas, with an average accuracy rate under cross-validation of 85%. There were ×20 magnification HE images that were more accurate in distinguishing orbital and conjunctival MALT lymphomas among ×4, ×20, and ×40. CONCLUSION: Artificial intelligence algorithms can successfully distinguish HE images between orbital and conjunctival MALT lymphomas.

Relationship between Vitreous IL-6 Levels, Gender Differences and C-Reactive Protein (CRP) in a Blood Sample of Posterior Uveitis.

This study retrospectively determined the relationship between vitreous IL-6 levels and clinical and laboratory data collected from uveitis patients. We examined an unknown cause of posterior uveitis, collecting vitreous fluid to investigate vitreous IL-6 levels. The samples were analyzed in consideration of clinical and laboratory factors, such as the male/female ratio. The present study included 82 eyes from 77 patients with a mean age of 66.20 ± 15.41 years. The IL-6 concentrations of the vitreous specimens were 6255.0 ± 14,108.3 pg/mL in males and 277.6 ± 746.3 pg/mL in females, which was found to be a statistically significant difference (p = 0.048) (n = 82). There was also a statistically significant correlation between vitreous IL-6 concentrations, serum C-reactive protein (CRP) value and white blood cell counts (WBCs) (n = 82). In multivariate analysis, vitreous IL-6 levels were significantly correlated with gender and CRP in all cases (p = 0.048 and p < 0.01, respectively) and were also significantly correlated with CRP in non-infectious uveitis (p < 0.01). In infectious uveitis, there were no significant differences between IL-6 level and several variables. Vitreous IL-6 concentrations were higher in males than in females in all cases. In non-infectious uveitis, vitreous IL-6 levels were correlated with serum CRP. These results might suggest that intraocular IL-6 levels depend on gender differences in posterior uveitis, and intraocular IL-6 levels in non-infectious uveitis may reflect systemic inflammations, including increased serum CRP.

Reconstruction of the Native Biosynthetic System of Carotenoids in E. coli─Biosynthesis of a Series of Carotenoids Specific to Paprika Fruit.

Capsanthin, capsorubin, cucurbitaxanthin A, and capsanthin 3,6-epoxide, a series of carotenoids specific to the red fruit of paprika (Capsicum annuum), were produced in pathway-engineered Escherichia coli cells. These cells functionally expressed multiple genes for eight carotenogenic enzymes, two of which, paprika capsanthin/capsorubin synthase (CaCCS) and zeaxanthin epoxidase (CaZEP), were designed to be located adjacently. The biosynthesis of these carotenoids, except for capsanthin, was the first successful attempt in E. coli. In a previous study, the levels of capsanthin synthesized were low despite the high expression of the CaCCS gene, which may have been due to the dual activity of CaCCS as a lycopene ß-cyclase and CCS. An enhanced interaction between CaCCS and CaZEP that supplies antheraxanthin and violaxanthin, substrates for CaCCS, was considered to be crucial for an efficient reaction. To achieve this, we adapted S·tag and S-protein binding. The S·tag Thrombin Purification Kit (Novagen) is merchandized for in vitro affinity purification, and S·tag-fused proteins in the E. coli lysate are specifically trapped by S-proteins fixed on the agarose carrier. Furthermore, S-proteins have been reported to oligomerize via C-terminal swapping. In the present study, CaCCS and CaZEP were individually fused to the S·tag and designed to interact on oligomerized S-protein scaffolds in E. coli, which led to the biosynthesis of not only capsanthin and capsorubin but also cucurbitaxanthin A and capsanthin 3,6-epoxide. The latter reaction by CaCCS was assigned for the first time. This approach reinforces the scaffold's importance for multienzyme pathways when native biosynthetic systems are reconstructed in microorganisms.

En-face widefield optical coherence tomography angiography for understanding vascular networks changes in two cases of acute retinal necrosis.

PURPOSE: The present study assesses the utility of en-face widefield optical coherence tomography angiography (OCTA) imaging for evaluating the retinal vascular network during the course of treatment in acute retinal necrosis(ARN). OBSERVATIONS: OCTA images of two cases of acute retinal necrosis were analyzed. Case 1 was a 15-year-old male with visual crowding in his right eye who had best-corrected visual acuity of 16/20 and intraocular pressure of 25 mmHg in his right eye on initial evaluation. Case 2 was a 57-year-old male with visual crowding in his left eye who had best-corrected visual acuity of 20/20 in his left eye on initial examination and intraocular pressure of 19.3 mmHg. In both patients, dynamic changes could be tracked by en-face ultra-widefield OCTA imaging before and up to 1 year after surgical treatment. The images showed arteriovenous anastomosis and the nonperfused area on the surface of the retina. CONCLUSIONS AND IMPORTANCE: En-face widefield OCTA is useful for monitoring the structure of retinal vessels over time in acute retinal necrosis. Wide-angle OCTA is used to non-invasively examine retinal vascular dynamic changes in ARN. OCTA artifacts due to intraocular inflammation appeared, making interpretation difficult. These will remain as issues in the future. It seems difficult for a while to completely replace FA due to the problem of image clarity.

Relationship between ultra-widefield optical coherence tomography and ophthalmoscopy for detecting posterior inflammation in posterior uveitis and panuveitis.

PURPOSE: To confirm the utility of ultra-widefield optical coherence tomography (W-OCT) for diagnosing uveitis. METHOD: We retrospectively studied patients who had been diagnosed with uveitis and had undergone W-OCT. All patients had visited at Osaka Metropolitan University between January 2019 and January 2022. On W-OCT, vitreous opacity ("W-OCT VO") and the presence of vitreous cells ("W-OCT Cells") were identified by three specialists. We compared findings from ophthalmoscopy ("Ophthalmoscopic findings") and fluorescein angiography ("FAG findings") with those from W-OCT. RESULTS: This study investigated 132 eyes from 68 patients (34 males, 34 females; mean age, 53.97±22.71 years). Vitreous cells in posterior uveitis and panuveitis differed significantly between "W-OCT Cells" and "Ophthalmoscopic findings" for all cases (P = 0.00014). Vitreous opacities in posterior uveitis and panuveitis did not differ significantly between "W-OCT VO" and "Ophthalmoscopic findings" (P = 0.144) for all cases. Compared to "Ophthalmoscopic findings", "W-OCT Cells" offered 51.1% sensitivity and 66.7% specificity for all cases (p<0.01). Compared to "Ophthalmoscopic findings", "W-OCT VO" offered 78.6% sensitivity and 30% specificity for all cases (p = 0.19). In addition, "W-OCT Cells" did not differ significantly from "FAG findings" for all cases (P = 0.424). CONCLUSION: W-OCT was shown to offer significantly greater sensitivity than ophthalmoscopy for detecting vitreous cells. The results of this study may add an option for the evaluation of uveitis.

Synthetic-biological approach for production of neoxanthin in Escherichia coli.

Carotenoids are isoprenoid pigments produced typically in plants, algae, and part of bacteria and fungi. Violaxanthin, neoxanthin, and lutein are xanthophylls biosynthesized specifically in land plants and part of algae. Nowadays, it is feasible to produce violaxanthin and lutein in Escherichia coli by pathway engineering, whereas there is no report to synthesize neoxanthin in E. coli. So far, several genes have been reported to code for neoxanthin synthases, e.g., NSY (NXS), ABA4 and VDL, which were assigned to catalyze a reaction for forming neoxanthin from violaxanthin. However, neither gene of these was common in plants or algae that biosynthesize neoxanthin, nor was confirmed by the E. coli complementation system. This study showed that the algal VDL gene (PtVDL1) was functional in recombinant E. coli cells accumulating violaxanthin to produce neoxanthin, whereas the E. coli cells failed to generate neoxanthin, when the NSY or ABA4 gene was introduced there instead of VDL. This result notes that VDL is one of veritable neoxanthin synthase genes.

En Face Images Using Ultra-Widefield Optical Coherence Tomography in 2 Cases of Traumatic Hypotony Maculopathy before and after Surgical Intervention.

The aim was to investigate the structural changes of the retina using en face ultra-widefield optical coherence tomography (OCT) images during the treatment of hypotony maculopathy with traumatic cyclodialysis. Case 1 was a 43-year-old male patient with visual crowding in his left eye (metallic wire injury that occurred 3 weeks previously) who was referred to our department. Although best-corrected visual acuity was 20/20 in his left eye on initial evaluation, intraocular pressure was 6 mm Hg. Case 2 was a 20-year-old male patient with visual crowding in his left eye (baseball ball injury that occurred 4 weeks previously) who was referred to our department. Although best-corrected visual acuity was 16/20 in his left eye on initial examination, intraocular pressure was 5 mm Hg. Surgical interventions were performed in both cases. En face ultra-widefield OCT images were able to be used to trace dynamic changes before the intervention and up to 1 year later. The images obtained in these two cases made it possible to confirm the progress from wrinkles on the surface of the retina to normalization of vascular structure and improvement of ellipsoid zone disruption. En face ultra-widefield OCT is useful for monitoring multilayer structures of the retina in hypotony maculopathy cases.

Changes of Crocin and Other Crocetin Glycosides in Saffron Through Cooking Models, and Discovery of Rare Crocetin Glycosides in the Yellow Flowers of Freesia Hybrida.

Crocetin glycosides such as crocin are noted as functional food materials since the preventive effects of crocin have been reported against chronic disease and cancer. However, it is unclear how these apocarotenoids are structurally changed through cooking for our intake. We examined such changes in crocetin glycosides (crocin, tricrocin, and crocin-3) contained in saffron (stigmas of Crocus sativus) through cooking models. These glycosides were almost kept stable in boiling for 20 min (a boiled cooking model), while hydrolysis of the ester linkage between glucose and the crocetin aglycone occurred in a grilled cooking model (180°C, 5 min), along with a 13-cis isomerization reaction in a part of crocetin subsequently generated. We further here revealed that the yellow petals of freesia (Freesia x hybrida) with yellow flowers accumulate two unique crocetin glycosides, which were identified to be crocetin (mono)neapolitanosyl ester and crocetin dineapolitanosyl ester. A similar result as above was obtained on their changes through the cooking models. Utility applications of the freesia flowers as edible flowers are also suggested in this study. Additionally, we evaluated singlet oxygen (1O2)-quenching activities of the crocetin glycosides contained in saffron and freesia, and crocetin and 13-cis crocetin contained in the grilled saffron, indicating that they possessed moderate 1O2-quenching activities (IC50 24-64 µM).

Carotenoids: Carotenoid and apocarotenoid analysis-Use of E. coli to produce carotenoid standards.

Authentic samples of many carotenoids are commercially available, but are often too expensive and of insufficient purity. As an alternative, a wide range of carotenoids can be biosynthesized in recombinant Escherichia coli strains. E. coli cells naturally produce the carotenoid biosynthetic precursors and provide a blank slate for manufacturing different target carotenoids, depending on the introduced genes encoding carotenoid biosynthetic enzymes. This chapter presents a series of plasmids that carry genes encoding carotenoid biosynthetic enzymes and methods to produce in E. coli 21 different carotenoids and two apocarotenoids, which can be used as authentic standards. For the structural confirmation of these carotenoids or apocarotenoids, we show their individual spectral data containing MS/MS and UV-visible, along with their biosynthetic routes in the E. coli transformants.

Orange protein, phytoene synthase regulator, has protein disulfide reductase activity.

Orange protein (OR) is known to interact with phytoene synthase (PSY) that commits the first step in carotenoid biosynthesis, and functions as a major post-transcriptional regulator on PSY. We here tried to reveal enzymatic characteristics of OR, that is, protein disulfide reductase (PDR) activity of the Arabidopsis thaliana OR protein (AtOR) was analyzed using dieosin glutathione disulfide (Di-E-GSSG) as a substrate. The AtOR part containing only the zinc (Zn)-finger motif was found to show PDR activity, with an apparent Km of 12,632 nM, Kcat of 11.85 min-1, and KcatKm-1 of 15.6 × 103 M-1sec-1. To evaluate the significance of the N-terminal region of AtOR, we examined the kinetic parameters of a fusion protein composed of the N-terminal region and the Zn-finger motif from AtOR. Consequently, the fusion protein had lower values for Km (2,074 nM) and Kcat (3.18 min-1) and higher catalytic efficiency (25.9 × 103 M-1sec-1) than that of only the Zn-finger motif part, suggesting that the N-terminal region of AtOR should be important for substrate affinity and catalytic efficiency of PDR activity. Complementation experiments with E. coli further demonstrated that AtOR containing the N-terminal region and the Zn-finger motif increases phytoene synthase activity of AtPSY especially under reduced circumstances retaining a NADPH- and H+-regeneration system.