Salvia officinalis flowers extract ameliorates liver and kidney injuries induced by simultaneous intoxication with ethanol/castor oil.

The current study investigated the possible mechanisms of aqueous extract Salvia officinalis flowers (SF-AE) and its protective effects against hepatorenal toxicities produced by simultaneous acute administration of ethanol (EtOH)/castor oil (CO). Healthy male rats (N = 50) were separated into five equal groups: control, Ethanol (EtOH) + Castor oil (CO), doses of increasing orders of SF-AE (50, 100, and 200 mg/kg, b.w., p.o.) during 15 days. Liver and kidney injuries were induced by EtOH (4 g/kg, b.w., p.o.) combined with CO (5 mL/kg, b.w., p.o.). Compared to the control group, SF-AE pretreatment protected against simultaneous administration of EtOH and CO-caused serious histological alterations in liver and kidney tissues. SF-AE also reversed liver and kidney biochemical parameters and lipid profile alterations. More importantly, SF-AE significantly reduced the malondialdehyde (MDA) level and counteracted the depletion of both enzymatic and non-enzymatic antioxidants. SF-AE also prevents against inflammation induced by EtOH combined with CO, expressed by the rise of inflammation biomarkers (C-reactive protein: CRP and alkaline phosphatase: ALP). Additionally, combined EtOH intoxication and CO poisoning exerted an increase in H2 O2 , free iron and calcium levels. Impressively, SF-AE treatment regulated levels of these studied intracellular mediators in a dose-dependent manner. In conclusion, SF-AE can potentially improve liver and kidney injuries associated with biochemical parameter deregulations, possibly by controlling oxidative stress and inflammation.

The Effect of Plasma-Treated Water on Microbial Growth and Biosynthesis of Gamma-Decalactones by Yarrowia lipolytica Yeast.

In recent years, the production of plasma-treated water (PTW) by low-temperature low-pressure glow plasma (LPGP) has been increasingly gaining in popularity. LPGP-treated water changes its physical and physiochemical properties compared to standard distilled water. In this study, a non-conventional lipolytic yeast species Yarrowia lipolytica was cultivated in culture media based on Nantes plasma water with heightened singlet oxygen content (Nantes PW) or in water treated with low-temperature, low-pressure glow plasma while in contact with air (PWTA) or nitrogen (PWTN). The research aimed to assess the influence of culture conditions on castor oil biotransformation to gamma-decalactone (GDL) and other secondary metabolites in media based on nanowater. The Nantes plasma water-based medium attained the highest concentration of gamma-decalactone (4.81 ± 0.51 g/L at 144 h of culture), maximum biomass concentration and biomass yield from the substrate. The amplified activity of lipases in the nanowater-based medium, in comparison to the control medium, is encouraging from the perspective of GDL biosynthesis, relying on the biotransformation of ricinoleic acid, which is the primary component of castor oil. Although lipid hydrolysis was enhanced, this step seemed not crucial for GDL concentration. Interestingly, the study validates the significance of oxygen in ß-oxidation enzymes and its role in the bioconversion of ricinoleic acid to GDL and other lactones. Specifically, media with higher oxygen content (WPTA) and Nantes plasma water resulted in remarkably high concentrations of four lactones: gamma-decalactone, 3-hydroxy-gamma-decalactone, dec-2-en-4-olide and dec-3-en-4-olide.

Regulation of capsule spine formation in castor.

Castor (Ricinus communis L.) is a dicotyledonous oilseed crop that can have either spineless or spiny capsules. Spines are protuberant structures that differ from thorns or prickles. The developmental regulatory mechanisms governing spine formation in castor or other plants have remained largely unknown. Herein, using map-based cloning in 2 independent F2 populations, F2-LYY5/DL01 and F2-LYY9/DL01, we identified the RcMYB106 (myb domain protein 106) transcription factor as a key regulator of capsule spine development in castor. Haplotype analyses demonstrated that either a 4,353-bp deletion in the promoter or a single nucleotide polymorphism leading to a premature stop codon in the RcMYB106 gene could cause the spineless capsule phenotype in castor. Results of our experiments indicated that RcMYB106 might target the downstream gene RcWIN1 (WAX INDUCER1), which encodes an ethylene response factor known to be involved in trichome formation in Arabidopsis (Arabidopsis thaliana) to control capsule spine development in castor. This hypothesis, however, remains to be further tested. Nevertheless, our study reveals a potential molecular regulatory mechanism underlying the spine capsule trait in a nonmodel plant species.

Skin pigmentation improvement with resveratrol microemulsion gel using polyoxyethylene hydrogenated castor oil.

OBJECTIVE: To investigate the safety and efficacy of resveratrol microemulsion gel in improving pigmentation. METHODS: Resveratrol microemulsion gel was prepared by the microemulsion solubilization method, and its quality was evaluated. The transdermal and drug retention rates of resveratrol in vivo were assessed using a transdermal test. The inhibitory effects of resveratrol suspension and microemulsion on tyrosinase activity and melanin production of A375 human melanocytes and zebrafish embryos were compared. A skin patch test was used to investigate the safety of the gel on 15 volunteers. RESULTS: The microemulsion gel was homogeneous and stable. Compared with suspension and microemulsion, the drug penetration rate and skin retention in the microemulsion gel group were significantly increased. Compared with the suspension group, the activity of melanocyte tyrosinase in A375 human melanocyte was significantly inhibited in the microemulsion group, and the melanin production rate of A375 human melanocyte and the melanin area of zebrafish yolk was decreased. All 15 volunteers tested negative for the human skin patch. CONCLUSIONS: The microemulsion gel could significantly enhance the ability of resveratrol to inhibit the formation of melanin without causing side effects. These data provide the experimental basis for developing and applying the preparation for improving pigmentation.

Autophosphorylation Inhibits RcCDPK1, a Dual-Specificity Kinase that Phosphorylates Bacterial-Type Phosphoenolpyruvate Carboxylase in Castor Oil Seeds.

Phosphoenolpyruvate carboxylase (PEPC) is a tightly regulated enzyme that plays a crucial anaplerotic role in central plant metabolism. Bacterial-type PEPC (BTPC) of developing castor oil seeds (COS) is highly expressed as a catalytic and regulatory subunit of a novel Class-2 PEPC heteromeric complex. Ricinus communis Ca2+-dependent protein kinase-1 (RcCDPK1) catalyzes in vivo inhibitory phosphorylation of COS BTPC at Ser451. Autokinase activity of recombinant RcCDPK1 was detected and 42 autophosphorylated Ser, Thr or Tyr residues were mapped via liquid chromatography-tandem mass spectrometry. Prior autophosphorylation markedly attenuated the ability of RcCDPK1 to transphosphorylate its BTPC substrate at Ser451. However, fully dephosphorylated RcCDPK1 rapidly autophosphorylated during the initial stages of a BTPC transphosphorylation assay. This suggests that Ca2+-dependent binding of dephospho-RcCDPK1 to BTPC may trigger a structural change that leads to rapid autophosphorylation and subsequent substrate transphosphorylation. Tyr30 was identified as an autophosphorylation site via LC-MS/MS and immunoblotting with a phosphosite-specific antibody. Tyr30 occurs at the junction of RcCDPK1's N-terminal variable (NTVD) and catalytic domains and is widely conserved in plant and protist CDPKs. Interestingly, a reduced rate and extent of BTPC transphosphorylation occurred with a RcCDPK1Y30F mutant. Prior research demonstrated that RcCDPK1's NTVD is essential for its Ca2+-dependent autophosphorylation or BTPC transphosphorylation activities but plays no role in target recognition. We propose that Tyr30 autophosphorylation facilitates a Ca2+-dependent interaction between the NTVD and Ca2+-activation domain that primes RcCDPK1 for transphosphorylating BTPC at Ser451. Our results provide insights into links between the post-translational control of COS anaplerosis, Ca2+-dependent signaling and the biological significance of RcCDPK1 autophosphorylation.

Carcass characteristics and meat evaluation of cattle finished in temperate pasture and supplemented with natural additive containing clove, cashew oil, castor oils, and a microencapsulated blend of eugenol, thymol, and vanillin.

BACKGROUND: Forty crossbred steers were supplemented with different doses (from 0 control to 6000 mg/animal/day) of natural additive blend containing clove essential oil, cashew oil, castor oil, and a microencapsulated blend of eugenol, thymol, and vanillin for 80 days. Carcass characteristics, drip loss, and antioxidant activity were evaluated 24 h post mortem on longissimus thoracis, and the effects of aging (until 14 days) were evaluated for water losses (thawing/aging and cooking), texture, color, and lipid oxidation. RESULTS: The use of the natural additive blend did not modify (P > 0.05) carcass characteristics but did, however, modify body composition (P < 0.05). Drip losses were unaffected by the treatments tested (P > 0.05). There was an observed quadratic effect (P < 0.05) on losses from thawing/aging on the first day of storage. Regarding the effects of natural additives on cooking losses, there was a quadratic effect (P < 0.05) among the treatments on day 7 of aging. Differences between days of aging were only observed with control treatment. Shear force was similar among treatments on days 1 and 7 of aging. On day 14 a linear effect (P < 0.05) was observed. Also, a linear effect (P < 0.05) appeared on meat lightness, meat from the control group being clearer on day 1. No changes were observed in redness among treatments or days of storage (P > 0.05). Yellowness was not modified by the treatments (P > 0.05)but only by the days of storage in control and the lowest dosage used. CONCLUSION: The blend of natural additives has potential use in pasture feeding and could improve meat quality. However, doses should be adjusted. © 2021 Society of Chemical Industry.

Lupeol Accumulation Correlates with Auxin in the Epidermis of Castor.

Lupeol, a natural lupane-type pentacyclic triterpene, possesses various pharmacological properties, and its production attracts attention. Significant quantities of lupeol are deposited on the castor aerial organ surface and are easily extractable as a predominant wax constituent. Thus, castor might be considered as a potential bioreactor for the production of lupeol. The lupeol biosynthesis pathway is well known, but how it is regulated remains largely unknown. Among large numbers of castor cultivars, we targeted one accession line (337) with high levels of lupeol on its stem surface and low levels thereof on its hypocotyl surface, implicating that lupeol synthesis is differentially regulated in the two organs. To explore the underlying mechanisms, we did comparative transcriptome analysis of the first internode of 337 stem and the upper hypocotyl. Our results show that large amounts of auxin-related genes are differentially expressed in both parts, implying some possible interactions between auxin and lupeol production. We also found that several auxin-responsive cis-elements are present in promoter regions of HMGR and LUS genes encoding two key enzymes involved in lupeol production. Furthermore, auxin treatments apparently induced the expression levels of RcHMGR and RcLUS. Furthermore, we observed that auxin treatment significantly increased lupeol contents, whereas inhibiting auxin transport led to an opposite phenotype. Our study reveals some relationships between hormone activity and lupeol synthesis and might provide a promising way for improving lupeol yields in castor.

Characterization of a PLDζ2 Homology Gene from Developing Castor Bean Endosperm.

Castor oil contains approximately 90% ricinoleic acid (RA) which is stored mainly in the form of tri-ricinoleic acid containing triacylglycerols (TAG). Ricinoleate is synthesized from oleate (18:1n-9) esterified to the sn-2 position of phosphatidylcholine (PtdCho) catalyzed by oleoyl-12-hydroxylase. PtdCho-derived diacylglycerol (DAG) is an important substrate pool for TAG synthesis, and the interconversion between PtdCho and DAG has been shown to play a critical role in channeling hydroxy fatty acids (HFA) to TAG. Although phospholipase D (PLD) has been reported to catalyze the hydrolysis of PtdCho to produce phosphatidic acid which can then be converted to DAG, its potential functions in the channeling of RA from PtdCho to DAG and the assembly of RA on TAG is largely unknown. In the present study, 11 PLD genes were identified from the Castor Bean Genome Database. Gene expression analysis indicated that RcPLD9 is expressed at relatively high levels in developing seeds compared to other plant tissues. Sequence and phylogenetic analyses revealed that RcPLD9 is a homolog of Arabidopsis PLDζ2. Overexpression of RcPLD9 in the Arabidopsis CL7 line producing C18-HFA resulted in RA content reductions in the polar lipid fraction (mainly PtdCho) and mono-HFA-TAG, but increased RA content in di-HFA-TAG. Since part of RA in di-HFA-TAG is derived from HFA-DAG, the results indicated that RcPLD9 facilitates the channeling of RA from PtdCho to DAG for its assembly on TAG in developing seeds.

Genomic Characterization and Expressional Profiles of Autophagy-Related Genes (ATGs) in Oilseed Crop Castor Bean (Ricinus communis L.).

Cellular autophagy is a widely-occurring conserved process for turning over damaged organelles or recycling cytoplasmic contents in cells. Although autophagy-related genes (ATGs) have been broadly identified from many plants, little is known about the potential function of autophagy in mediating plant growth and development, particularly in recycling cytoplasmic contents during seed development and germination. Castor bean (Ricinus communis) is one of the most important inedible oilseed crops. Its mature seed has a persistent and large endosperm with a hard and lignified seed coat, and is considered a model system for studying seed biology. Here, a total of 34 RcATG genes were identified in the castor bean genome and their sequence structures were characterized. The expressional profiles of these RcATGs were examined using RNA-seq and real-time PCR in a variety of tissues. In particular, we found that most RcATGs were significantly up-regulated in the later stage of seed coat development, tightly associated with the lignification of cell wall tissues. During seed germination, the expression patterns of most RcATGs were associated with the decomposition of storage oils. Furthermore, we observed by electron microscopy that the lipid droplets were directly swallowed by the vacuoles, suggesting that autophagy directly participates in mediating the decomposition of lipid droplets via the microlipophagy pathway in germinating castor bean seeds. This study provides novel insights into understanding the potential function of autophagy in mediating seed development and germination.

Lipase-mediated synthesis of ricinoleic acid vanillyl ester and evaluation of antioxidant and antibacterial activity.

Castor oil extracted from castor bean has antibacterial property, and has been used in various folk remedies. The major structural component of castor oil, ricinoleic acid, has actual antibacterial activity. Some phenolic compounds derived from plants have antioxidant property. Among them, vanillyl alcohol from vanilla bean has strong antioxidant activity. As vanillyl alcohol has low solubility in hydrophobic solvents and castor oil has low solubility in hydrophilic solvents, there is practical difficulty in using them. We performed lipase-mediated transesterification using vanillyl alcohol and castor oil, and synthesized ricinoleic acid vanillyl ester (RAVE). 2,2-Diphenyl-1-picrylhydrazyl assay and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) assay revealed that RAVE had a strong antioxidant activity in various organic solvents. RAVE also had antibacterial activity against some food spoilage bacteria. It showed more powerful antibacterial activity for gram positive bacteria than for gram negative bacteria. The critical micelle concentration of RAVE was measured at 7.36 µM and it partitioned exclusively into emulsion phase in water-emulsion system. Zeta potential measurement, membrane release test, and fluorescent microscopy showed that RAVE inserted itself into the bacterial cell membrane, destroyed membrane permeability, and induced cell death. As such, RAVE is a novel multi-functional compound with antioxidant and antibacterial activity, so it can be used as a functional material in the food and cosmetic industries.

Lipase of Pseudomonas guariconesis as an additive in laundry detergents and transesterification biocatalysts.

A newly isolated culture, Pseudomonas guariconesis, is reported for the first time for lipase production. Various process parameters affecting enzyme production were optimized through statistical design experiments. The Plackett-Burman experimental design was used for screening 10 parameters for lipase production, which was further optimized using the central composite design of response surface methodology. Maximum lipase activity of 220 U/ml was obtained after 24 h of incubation in shake-flask cultures with an inoculum concentration of 0.6% v/v, incubation temperature of 30°C, and medium pH 9.0. Castor oil (0.5% v/v) was used as the inducer for lipase production. The enzyme was found to be compatible with five different commercial detergents, indicating its potential to be used in detergent formulations. It also acted as a biocatalyst in a transesterification process. The alkaline enzyme was found to be stable in the presence of bleaching agents, metal ions, and organic solvents as well.

Effects of functional oils on performance and carcass characteristics of broilers under two different temperature environments.

As antioxidants such as some functional oils are good candidates to mitigate heat stress, a commercial blend of functional oils (Essential, Oligo Basics USA LLC, Cary, NC; active ingredients: cashew nut shell oil and castor oil) was used to study the effects of two ambient temperatures (moderate and high) on broiler chicken performance and carcass parameters. A total of 2,240 straight-run one-day-old chickens were sorted by weight, randomized among 28 floor pens with 80 chickens per pen and 7 replicates for each treatment. Birds were assigned to one of 4 dietary treatments in a 2 × 2 factorial arrangement with two temperature environments (moderate and high) and without or with Essential supplementation (1.5 kg/ton). Variances for the average temperature, relative humidity, and dew point for the two environments were different (P < 0.001), showing that the high-temperature environment reached higher temperatures and dew points. Essential supplementation increased body weight gain at 42 D of age (2.548 vs. 2.508 kg; P < 0.01) and tended to improve feed conversion (1.621 vs. 1.644; P = 0.09) independent of temperature environment. The high-temperature environment increased mortality (7.5 vs. 12.4%; P = 0.03) and carcass yields (77.5 vs. 76.2%; P < 0.01). Breast yields were affected by an environment by Essential interaction (P < 0.01). Whereas the high-temperature environment decreased breast yield in control birds, it did not decrease breast yield in birds supplemented with Essential. Finally, breast yields were increased by Essential supplementation (23.6 vs. 22.9%; P < 0.01) regardless of the ambient temperature. In conclusion, Essential supplementation improved weight gains and carcass characteristics, and high-temperature environments decreased breast yields when Essential was not supplemented.

Tissue-specific differences in metabolites and transcripts contribute to the heterogeneity of ricinoleic acid accumulation in Ricinus communis L. (castor) seeds.

INTRODUCTION: Castor (Ricinus communis L.) seeds are valued for their production of oils which can comprise up to 90% hydroxy-fatty acids (ricinoleic acid). Castor oil contains mono-, di- and tri- ricinoleic acid containing triacylglycerols (TAGs). Although the enzymatic synthesis of ricinoleic acid is well described, the differential compartmentalization of these TAG molecular species has remained undefined. OBJECTIVES: To examine the distribution of hydroxy fatty acid accumulation within the endosperm and embryo tissues of castor seeds. METHODS: Matrix assisted laser desorption/ionization mass spectrometry imaging was used to map the distribution of triacylglycerols in tissue sections of castor seeds. In addition, the endosperm and embryo (cotyledons and embryonic axis) tissues were dissected and extracted for quantitative lipidomics analysis and Illumina-based RNA deep sequencing. RESULTS: This study revealed an unexpected heterogeneous tissue distribution of mono-, di- and tri- hydroxy-triacylglycerols in the embryo and endosperm tissues of castor seeds. Pathway analysis based on transcript abundance suggested that distinct embryo- and endosperm-specific mechanisms may exist for the shuttling of ricinoleic acid away from phosphatidylcholine (PC) and into hydroxy TAG production. The embryo-biased mechanism appears to favor removal of ricinoleic acid from PC through phophatidylcholine: diacylglycerol acyltransferase while the endosperm pathway appears to remove ricinoleic acid from the PC pool by preferences of phospholipase A (PLA2α) and/or phosphatidylcholine: diacylglycerol cholinephosphotransferase. CONCLUSIONS: Collectively, a combination of lipidomics and transcriptomics analyses revealed previously undefined spatial aspects of hydroxy fatty acid metabolism in castor seeds. These studies underscore a need for tissue-specific studies as a means to better understand the regulation of triacylglycerol accumulation in oilseeds.

Multi-Layered Nanomicelles as Self-Assembled Nanocarrier Systems for Ocular Peptide Delivery.

Despite the great potential of peptides as therapeutics, there is an unmet challenge in sustaining delivery of sufficient amounts in their native forms. This manuscript describes a novel nanocarrier capable of delivering functional small peptides in its native form. Self-assembling multi-layered nanomicelles composed of two polymers, polyoxyethylene hydrogenated castor oil 40 (HCO-40) and octoxynol 40 (OC-40), were designed to combine hydrophilic interaction and solvent-induced encapsulation of peptides and proteins. The polymers are employed to encapsulate peptide or protein in the core of the organo-nanomicelles which are further encapsulated with another layer of the same polymers to form an aqueous stable nanomicellar solution. The size of the multi-layered nanomicelles ranges from ~ 16 to 20 nm with zeta potential close to neutral (~ - 2.44 to 0.39 mV). In vitro release studies revealed that octreotide-loaded multi-layered nanomicelles released octreotide at much slower rate in simulated tear fluid (STF) (~ 27 days) compared to PBST (~ 11 days) in its native form. MTT assay demonstrated negligible toxicity of the multi-layered nanomicelles at lower concentrations in human retinal pigment epithelial (HRPE, D407), human conjunctival epithelial (CCL 20.2), and rhesus choroid-retinal endothelial (RF/6A) cells. This work demonstrates an efficient small peptide delivery platform with significant advantages over existing approaches, as it does not require modification of the peptide, is biodegradable, and has a small size and high loading capacity.

One-pot conjugated linoleic acid production from castor oil by Rhizopus oryzae lipase and resting cells of Lactobacillus plantarum.

Conjugated linoleic acid (CLA) has attracted as novel type of fatty acids having unusual health-promoting properties such as anticarcinogenic and antiobesitic effects. The present work employed castor oil as substrate for one-pot production of CLA using washed cells of Lactobacillus plantarum (L. plantarum) and lipases as catalysts. Among the screened lipases, the lipase Rhizopus oryzae (ROL) greatly assisted resting cells to produce CLA. Mass spectral analysis of the product showed that two major isomers of CLA were produced in the reaction mixture i.e. cis-9, trans-11 56.55% and trans-10, cis-12 43.45%. Optimum factors for CLA synthesis were found as substrate concentration (8 mg/mL), pH (6.5), washed cell concentration (12% w/v), and incubation time of 20 h. Hence, the combination of ROL with L. plantarum offers one pot production of CLA selectively using castor oil as a cost-effective substrate.

Regulatory Phosphorylation of Bacterial-Type PEP Carboxylase by the Ca2+-Dependent Protein Kinase RcCDPK1 in Developing Castor Oil Seeds.

Phosphoenolpyruvate carboxylase (PEPC) is a tightly controlled cytosolic enzyme situated at a crucial branch point of central plant metabolism. In developing castor oil seeds (Ricinus communis) a novel, allosterically desensitized 910-kD Class-2 PEPC hetero-octameric complex, arises from a tight interaction between 107-kD plant-type PEPC and 118-kD bacterial-type (BTPC) subunits. The native Ca2+-dependent protein kinase (CDPK) responsible for in vivo inhibitory phosphorylation of Class-2 PEPC's BTPC subunit's at Ser-451 was highly purified from COS and identified as RcCDPK1 (XP_002526815) by mass spectrometry. Heterologously expressed RcCDPK1 catalyzed Ca2+-dependent, inhibitory phosphorylation of BTPC at Ser-451 while exhibiting: (i) a pair of Ca2+ binding sites with identical dissociation constants of 5.03 µM, (ii) a Ca2+-dependent electrophoretic mobility shift, and (iii) a marked Ca2+-independent hydrophobicity. Pull-down experiments established the Ca2+-dependent interaction of N-terminal GST-tagged RcCDPK1 with BTPC. RcCDPK1-Cherry localized to the cytosol and nucleus of tobacco bright yellow-2 cells, but colocalized with mitochondrial-surface associated BTPC-enhanced yellow fluorescent protein when both fusion proteins were coexpressed. Deletion analyses demonstrated that although its N-terminal variable domain plays an essential role in optimizing Ca2+-dependent RcCDPK1 autophosphorylation and BTPC transphosphorylation activity, it is not critical for in vitro or in vivo target recognition. Arabidopsis (Arabidopsis thaliana) CPK4 and soybean (Glycine max) CDPKß are RcCDPK1 orthologs that effectively phosphorylated castor BTPC at Ser-451. Overall, the results highlight a potential link between cytosolic Ca2+ signaling and the posttranslational control of respiratory CO2 refixation and anaplerotic photosynthate partitioning in support of storage oil and protein biosynthesis in developing COS.

Enzymatic incorporation of caffeoyl into castor oil to prepare the novel castor oil-based caffeoyl structured lipids.

In this work, a novel castor oil-based caffeoyl structured lipids was successfully prepared by the enzymatic transesterification using castor oil (CO) as caffeoyl acceptor. During the structured lipids preparation, two competitive reactions, the hydrolysis of CO to form hydrophilic caffeoyl glycerols (CG)+dicaffeoyl glycerols (DCG) and the transesterification of CO with ethyl caffeate (EC) to form lipophilic caffeoyl mono- and di-acylglycerols (CMAG and CDAG), were found. Reaction progress was monitored using HPLC-ESI-MS and HPLC-UV. The effects of by-product ethanol removal and reaction variables on the transesterification and reaction selectivity were evaluated. Results showed that, the activation energies for the transesterification and for the selective formations of CMAG+CDAG and CG+DCG were 57.60kJ/mol, 58.86kJ/mol, and 60.53kJ/mol, respectively. Under the optimal reaction conditions (enzyme load 23%, 90°C, 1:3 molar ratio of EC to CO, and 46.5h), EC conversion and the yield of CMAG+CDAG were 93.68±2.52% and 78.11±1.35%, respectively.

The calcium-dependent protein kinase RcCDPK2 phosphorylates sucrose synthase at Ser11 in developing castor oil seeds.

Imported sucrose is cleaved by sucrose synthase (SUS) as a critical initial reaction in the biosynthesis of storage end-products by developing seeds. Although SUS is phosphorylated at a conserved seryl residue by an apparent CDPK (Ca2+-dependent protein kinase) in diverse plant tissues, the functions and mechanistic details of this process remain obscure. Thus, the native CDPK that phosphorylates RcSUS1 (Ricinus communis SUS1) at Ser11 in developing COS (castor oil seeds) was highly purified and identified as RcCDPK2 by MS/MS. Purified RcSUS1-K (-kinase) and heterologously expressed RcCDPK2 catalyzed Ca2+-dependent Ser11 phosphorylation of RcSUS1 and its corresponding dephosphopeptide, while exhibiting a high affinity for free Ca2+ ions [K0.5(Ca2+) < 0.4 µM]. RcSUS1-K activity, RcCDPK2 expression, and RcSUS1 Ser11 phosphorylation peaked during early COS development and then declined in parallel. The elimination of sucrose import via fruit excision triggered RcSUS1 dephosphorylation but did not alter RcSUS1-K activity, suggesting a link between sucrose signaling and posttranslational RcCDPK2 control. Both RcCDPK2-mCherry and RcSUS1-EYFP co-localized throughout the cytosol when transiently co-expressed in tobacco suspension cells, although RcCDPK2-mCherry was also partially localized to the nucleus. Subcellular fractionation revealed that ∼20% of RcSUS1-K activity associates with microsomal membranes in developing COS, as does RcSUS1. In contrast with RcCDPK1, which catalyzes inhibitory phosphorylation of COS bacterial-type phosphoenolpyruvate carboxylase at Ser451, RcCDPK2 exhibited broad substrate specificity, a wide pH-activity profile centered at pH 8.5, and insensitivity to metabolite effectors or thiol redox status. Our combined results indicate a possible link between cytosolic Ca2+-signaling and the control of photosynthate partitioning during COS development.

High light exposure on seed coat increases lipid accumulation in seeds of castor bean (Ricinus communis L.), a nongreen oilseed crop.

Little was known on how sunlight affects the seed metabolism in nongreen seeds. Castor bean (Ricinus communis L.) is a typical nongreen oilseed crop and its seed oil is an important feedstock in industry. In this study, photosynthetic activity of seed coat tissues of castor bean in natural conditions was evaluated in comparison to shaded conditions. Our results indicate that exposure to high light enhances photosynthetic activity in seed coats and consequently increases oil accumulation. Consistent results were also reached using cultured seeds. High-throughput RNA-Seq analyses further revealed that genes involved in photosynthesis and carbon conversion in both the Calvin-Benson cycle and malate transport were differentially expressed between seeds cultured under light and dark conditions, implying several venues potentially contributing to light-enhanced lipid accumulation such as increased reducing power and CO2 refixation which underlie the overall lipid biosynthesis. This study demonstrated the effects of light exposure on oil accumulation in nongreen oilseeds and greatly expands our understanding of the physiological roles that light may play during seed development in nongreen oilseeds. Essentially, our studies suggest that potential exists to enhance castor oil yield through increasing exposure of the inflorescences to sunlight either by genetically changing the plant architecture (smart canopy) or its growing environment.

Lipase catalyzed transesterification of castor oil by straight chain higher alcohols.

Biolubricants from Castor oil were produced enzymatically by transesterification with higher alcohols using a lipase mixture of immobilized Mucor miehei (RMIM) and immobilized Candida antarctica lipase B (Novozym 435) under low water conditions. The conversions were in the range of 80-95% under the optimized conditions.