Cytogenetic bioassays as tools to distinguish between toxic and non-toxic varieties of Jatropha curcas (Euphorbiaceae)

Abstract The tropical and subtropical naturalized physic nut (Jatropha curcas L.), has been explored for biodiesel production in recent times. The oil is extracted from the seeds and, for the production to be feasible, utilization of the residual seed cake is crucial. Although the cake could be employed as a protein source in animal feed, it is rich in phorbol ester, which is toxic for animals. Therefore, breeding programs have been working to reduce or eliminate the phorbol ester content in physic nut. In this context, the present work aimed to evaluate the physic nut oil of toxic and non-toxic varieties (containing known or undetectable amounts of phorbol ester, respectively) with regards to phytotoxicity in a model experiment with Lactuca sativa L. For this, the percentage of germinated seeds was evaluated after 8, 16, 24, 36 and 48 hours of exposure to the treatments with toxic and non-toxic oil at concentrations of 22.5 %, 45 % and 67.5 % of emulsion (physic nut oil energetically mixed with distilled water). Root growth was determined after 48 hours of exposure and the germination speed index was obtained. The different stages of mitotic division as well as possible chromosomal and nuclear alterations were also recorded. The mitotic index was calculated as the number of dividing cells, as a fraction of the total number of cells, and the frequency of chromosome and nuclear alterations, expressed as the percentage of number of alterations divided by the total number of cells. Both varieties exhibited phytotoxicity, inducing significant reductions in percentage of germinated seeds (reduction of 98 %), germination speed index (reduction of 24.44) and root growth (reduction of 8.54 mm). In microscopic analysis, a mitodepressive effect was observed for both oils at the three concentrations used when compared to the negative control; however, it was possible to distinguish between the toxic and the non-toxic varieties based on the more expressive reduction of division promoted by the first, 2.19 %. Significant increments in the frequency of mitotic cells showing chromosome alterations as well, as the presence of condensed nuclei, were observed in the treated cells. However, these parameters were not significantly different from the control in the cells treated with both physic nut oils. In conclusion, the evaluation of root growth and cell division in the plant model L. sativa, can be proposed as an alternative to animal tests to distinguish the varieties with high and low phorbol ester concentration, thus contributing to the detection of toxicity in varieties used in breeding programs.

Resumen Jatropha curcas L., naturalizado tropical y subtropical, ha sido explorado para la producción de biodiesel. El aceite se extrae de las semillas y, para que la producción sea factible, la utilización de la torta de semillas residual es crucial. Aunque la torta se puede emplear como una fuente de proteína en la alimentación animal, es rica en éster de forbol, que es tóxico para los animales. Por lo tanto, los programas de mejoramiento han procurado reducir o eliminar el contenido de éster de forbol de J. curcas. En este contexto, el presente trabajo tuvo como objetivo evaluar el aceite de J. curcas de las variedades tóxicas y no tóxicas (con cantidades conocidas o indetectables de éster de forbol, respectivamente) con respecto a la fitotoxicidad en el modelo Lactuca sativa L. El porcentaje de semillas germinadas se evaluó después de 8, 16, 24, 36 y 48 horas de tratamiento. El crecimiento de la raíz se determinó después de 48 horas de exposición y se obtuvo el índice de velocidad de germinación. Se registraron las diferentes etapas de la división mitótica así como posibles alteraciones cromosómicas y nucleares. El índice mitótico se calculó como el número de células en división como una fracción del número total de células y la frecuencia de las alteraciones cromosómicas y nucleares, expresada como el porcentaje del número de alteraciones dividido entre el número total de células. Ambas variedades exhibieron fitotoxicidad, induciendo reducciones significativas en el porcentaje de semillas germinadas (Reducción del 98 %), índice de velocidad de germinación (Reducción de 24.44) y crecimiento de raíces (Reducción de 8.54 mm). En el análisis microscópico, se observó un efecto mitodepresivo para ambos aceites. Sin embargo, fue posible distinguir entre las variedades tóxicas y las no tóxicas basándose en la reducción más expresiva de la división promovida por la primera, 2.19 %. Se observaron incrementos significativos en la frecuencia de células mitóticas que mostraban alteraciones cromosómicas, así como la presencia de núcleos condensados en las células tratadas. Sin embargo, estos parámetros no fueron significativamente diferentes del control en las células tratadas con ambos aceites de J. curcas. En conclusión, la evaluación del crecimiento de las raíces y la división celular en el modelo L. sativa se puede proponer como una alternativa a las pruebas en animales para distinguir las variedades con concentraciones altas y bajas de éster de forbol, contribuyendo así a la detección de toxicidad en variedades utilizadas en programas de mejoramiento genético.

Endothelium Independent Effect of Pelargonidin on Vasoconstriction in Rat Aorta

In this study, we investigated the effects of pelargonidin, an anthocyanidin found in many fruits and vegetables, on endothelium-independent vascular contractility to determine the underlying mechanism of relaxation. Isometric contractions of denuded aortic muscles from male rats were recorded, and the data were combined with those obtained in western blot analysis. Pelargonidin significantly inhibited fluoride-, thromboxane A2-, and phorbol ester-induced vascular contractions, regardless of the presence or absence of endothelium, suggesting a direct effect of the compound on vascular smooth muscles via a different pathway. Pelargonidin significantly inhibited the fluoride-dependent increase in the level of myosin phosphatase target subunit 1 (MYPT1) phosphorylation at Thr-855 and the phorbol 12,13-dibutyrate-dependent increase in the level of extracellular signal-regulated kinase (ERK) 1/2 phosphorylation at Thr202/Tyr204, suggesting the inhibition of Rho-kinase and mitogen-activated protein kinase kinase (MEK) activities and subsequent phosphorylation of MYPT1 and ERK1/2. These results suggest that the relaxation effect of pelargonidin on agonist-dependent vascular contractions includes inhibition of Rho-kinase and MEK activities, independent of the endothelial function.

Hypothermia Inhibits Endothelium-Independent Vascular Contractility via Rho-kinase Inhibition

The present study was undertaken to investigate the influence of hypothermia on endothelium-independent vascular smooth muscle contractility and to determine the mechanism underlying the relaxation. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Hypothermia significantly inhibited fluoride-, thromboxane A2-, phenylephrine-, and phorbol ester-induced vascular contractions regardless of endothelial nitric oxide synthesis, suggesting that another pathway had a direct effect on vascular smooth muscle. Hypothermia significantly inhibited the fluoride-induced increase in pMYPT1 level and phorbol ester-induced increase in pERK1/2 level, suggesting inhibition of Rho-kinase and MEK activity and subsequent phosphorylation of MYPT1 and ERK1/2. These results suggest that the relaxing effect of moderate hypothermia on agonist-induced vascular contraction regardless of endothelial function involves inhibition of Rho-kinase and MEK activities.

Transcriptome characterization of Stellera chamaejasme with Illumina sequencing technology / 中草药

Objective To obtain the transcriptome database and gene sequence, SSR as well as transposon information of Stellera chamaejasme. Methods Using the high-throughput sequencing platform (Illumina HiSeq 2000), a root transcriptome dataset of S. chamaejasme was obtained, and the sequencing results were analyzed with the bioinformatic way. Results With a total of 26 785 872 clean reads, 47 053 unigenes were assembled. All these unigenes were then blasted with Nr, Swiss-Prot, KEGG, COG, and GO databases. There were 11 138 and 24 744 unigenes were annotated with Nr and Swiss-Prot databases, respectively. The unigenes were involved in 36 GO-terms and 119 metabolic pathways. Further analysis showed that 15 unigenes were involved in terpenoids biosynthesis. Using MISA software, the results showed that there were 3 480 SSR from the 47 053 unigenes, and the most type of SSR was mononucleotide (1 986) with the frequency of 57.07%. Moreover, the hexanucleotide only had five repeat SSR and the frequency was only 0.14%. With RepeatMasker online tools to analyze the transposon of the transcriptome sequences, the results indicated that there were 1 497 transposons, and the number of transposons with E < 1×10-5 was 827. All the transposons were grouped into 22 types, and the LINE/L1 type (405) had the highest frequency (48.97%). The DNA/Ginger, DNA/hAT, DNA/PIF-ISL2EU, and LINE/Jockey as well as LTR/Lenti were the least type since each of them has only one transposon. Conclusion In this study, rich sequence information of gene, SSR as well as transposon information of Stellera chamaejasme is helpful to carry out the research of the molecular mechanism of phorbol ester biosynthesis in S. chamaejasme in the future.

Endothelium-Independent Effect of Fisetin on the Agonist-Induced Regulation of Vascular Contractility

Fisetin, a natural flavonoid found in a variety of vegetables and fruits, has been shown to possess many biological functions. The present study was undertaken to investigate the influence of fisetin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Fisetin significantly relaxed fluoride-, thromboxane A2- or phorbol ester-induced vascular contraction suggesting as a possible anti-hypertensive on the agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, fisetin significantly inhibited fluoride-induced increases in pMYPT1 levels and phorbol ester-induced increases in pERK1/2 levels suggesting the mechanism involving the inhibition of Rho-kinase activity and the subsequent phosphorylation of MYPT1 and MEK activity and the subsequent phosphorylation of ERK1/2. This study provides evidence regarding the mechanism underlying the relaxation effect of fisetin on agonist-induced vascular contraction regardless of endothelial function.

The Inhibitory Effect of Shikonin on the Agonist-Induced Regulation of Vascular Contractility

Shikonin, a natural flavonoid found in the roots of Lithospermum erythrorhizon, has been shown to possess many biological functions. The present study was undertaken to investigate the influence of shikonin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Shikonin significantly relaxed fluoride-, thromboxane A2- or phorbol ester-induced vascular contraction suggesting as a possible anti-hypertensive on the agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, shikonin significantly inhibited fluoride-induced increases in pMYPT1 levels and phorbol ester-induced increases in pERK1/2 levels suggesting the mechanism involving the inhibition of Rho-kinase activity and the subsequent phosphorylation of MYPT1 and the inhibition of MEK activity and the subsequent phosphorylation of ERK1/2. This study provides evidence regarding the mechanism underlying the relaxation effect of shikonin on agonist-induced vascular contraction regardless of endothelial function.

The Inhibitory Effect of Apigenin on the Agonist-Induced Regulation of Vascular Contractility via Calcium Desensitization-Related Pathways

Apigenin, a natural flavonoid found in a variety of vegetables and fruits, has been shown to possess many biological functions. The present study was undertaken to investigate the influence of apigenin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Apigenin significantly relaxed fluoride-, thromboxane A2 mimetic- or phorbol ester-induced vascular contraction, which suggests that apigenin could be an anti-hypertensive that reduces agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, apigenin significantly inhibited fluoride-induced increases in pMYPT1 levels and phorbol ester-induced increases in pERK1/2 levels, which suggests the mechanism involving the inhibition of Rho-kinase and MEK activity and the subsequent phosphorylation of MYPT1 and ERK1/2. This study provides evidence regarding the mechanism underlying the relaxation effect of apigenin on agonist-induced vascular contraction regardless of endothelial function.

Chemistry of Phorbol Ester Toxicity in Jatropha curcas Seed – a Review.

The toxicity of Jatropha curcas seeds emanates mainly from phorbol esters. It is known that the seeds are a valuable source of oil, which can be used to produce biodiesel. The cake generated as a by-product, after oil pressing is a protein-rich potential stock for animal feed. Researchers, the world over, have studied these phorbol esters and investigated ways of improving the applications of the seed meal. This review paper outlines the previous research done on the Jatropha curcas plant, the toxicity of phorbol esters and the efforts made to detoxify the seed. It also highlights the knowledge gaps concerning the chemistry of phorbol ester toxicity and the probable areas of future research.

The study of induction and differentiation of leukemic cell by phorbol ester / 白血病·淋巴瘤

12-O-tetradecanoylphorbol-13-acetate (TPA) is an activator of protein kinase C (PKC)extracted from the croton oil, it is one of the most powerful inducers of differentiation as well as a powerful tumor promoter. It is used by the study of induction and differentiation generally, because of it can induce the differentiation of tumor cell and promote the lymphocyte transformation and secrete of lymphokine, meanwhile,it is able to induce many kinds of cell of leukemic cell strain like HL-60, HEL and so on, Some literature reported that TPA had the function of differentiation of primary leukemic cell. The article mainly explains the induction and differentiation of leukemic cell by phorbol ester as well as its mechanisms, which to provide the theory evidence for prevention and cure of leukemia.

Effect of mesenchymal stem cell on the rate of Th1/Th2 with different stimulations / 基础医学与临床

Objective To investigate the effect of mesenchymal stem cell(MSC) on the balance of Th1/ Th2 with different stimulations.Methods To inoculate MSC in 24-well tissue culture plates.after 3 days, added T lymphocytes co-stimulated by PMA and Ionomycin,or the MSC were added to the two-way mixed lymphocyte culture according to different proportion.The subsets and cytokines of T lymphocytes were analyzed by flow cytomety.Results Differentiation into Th1 of T lymphocytes activated by co-stimulation can be inhibited MSC;In MLC,CD8~+T cell subsets and Th1 were evidently decreased.But Th2 cells were slightly increased.Conclusion MSC can significantly suppress CD8~(+)T cell,Th1,increase Th2.MSC has potentialities of alleviating acute graft-versus-host disease(aGVHD) and maintaining graft versus leukemia(GVL).

Expression of Human Melanocyte Markers in PMA-containing Medium and Physiologic Mitogen-containing Medium / 대한피부과학회지

BACKGROUND: There are many growth media for cultivation of human melanocytes (MGM), depending on the supplements added, and the growth of cells is closely related to these components. To understand melanocytes in vivo, it is necessary to find out the biological or biochemical characteristics of melanocytes grown in physiologic growth medium (P-MGM) and phorbol-12-myristate 13-acetate (PMA)-containing medium (C-MGM). OBJECTIVE: To investigate the expression of different biochemical markers of melanocytes grown in C-MGM and in P-MGM. METHODS: C-MGM is basically composed of PMA (10 ng/ml), and bFGF (3 ng/ml), and is now commercially available for melanocyte culture. P-MGM is a physiologic growth medium containing physiologic mitogens such as bFGF (10 ng/ml), ET-1 (10 nM), and alpha-MSH (12 nM). The cell proliferation and the expression of biochemical markers were measured in cultured human melanocytes which were grown in either C-MGM or P-MGM. RESULTS: In this study, there was significant difference in cell proliferation between cells grown in C-MGM and P-MGM (p<0.01). The tyrosinase activity and melanin contents were significantly increased in C-MGM. The expression of TRP1, MART-1 and p53 in mRNA level was higher in C-MGM than in P-MGM. The up-regulation of p53 protein expression was also observed in C-MGM. CONCLUSION: The proliferation and expression of p53, at both transcriptional and translational levels were increased when melanocytes were grown in C-MGM, compared to P-MGM. This data suggests that p53-mediated melanization is to some degree related with phorbol ester, and should further be elucidated.

Caffeic Acid Phenethyl Ester Inhibits the PKC-Induced IL-6 Gene Expression in the Synoviocytes of Rheumatoid Arthritis Patients

To gain insight on the role of pro-inflammatory cytokines in the pathogenesis and treatment of rheumatoid arthritis (RA), the phorbol 12-myristate 13-acetate (PMA) -induced IL-6 gene expression and the effect of caffeic acid phenethyl ester (CAPE) on the PMA-induced IL-6 gene expression were investigated in human fibroblast-like synoviocytes (FLSs). Synovial tissue samples were obtained from rheumatoid arthritis patients, and FLSs were isolated. The cells were stimulated with PMA (100 nM) for 6 hrs to induce IL-6 gene. The cells were pretreated with CAPE (20, 50, 100 microM) prior to PMA treatment. PMA increased IL-6 RNA expression, binding activities of transcription factors (NF-kappaB, AP-1) to IL-6 promoter, and IL-6 promoter activity. However, CAPE inhibited PMA-induced IL-6 mRNA expression in dose-dependent manner, and also inhibited the increased binding activities of transcription factors to IL-6 promoter and IL-6 promoter activity. These results suggest that CAPE might regulate PKC-mediated IL-6 expression and inflammatory reactions in RA.

The Role of Protein Kinase C and Its Effect on GHRH in the Regulation of Hormone Secretion by Somatotrophinomas / 华中科技大学学报（医学）（英德文版）

Phorbol ester-induced release of growth hormone (GH) and prolactin (PRL) from human somatotrophic tumors was examined in vitro. 12-O-tetradecanoyl-phorbol-13- acetate (TPA)strongly stimulated GH and PRL secretion and showed an additive effect on GH secretion if used in combination with GH releasing hormone (GHRH). In contrast, staurosporine exerted a variable inhibitory effect on GH release. There was no correlation between such effects and gsp mutations.The findings suggested that TPA doesn't act directly through cAMP signal transduction system.

The Role of Protein Kinase C and Its Effect on GHRH in the Regulation of Hormone Secretion by Somatotrophinomas / 华中科技大学学报（医学）（英德文版）

Phorbol ester-induced release of growth hormone (GH) and prolactin (PRL) from human somatotrophic tumors was examined in vitro. 12-O-tetradecanoyl-phorbol-13- acetate (TPA)strongly stimulated GH and PRL secretion and showed an additive effect on GH secretion if used in combination with GH releasing hormone (GHRH). In contrast, staurosporine exerted a variable inhibitory effect on GH release. There was no correlation between such effects and gsp mutations.The findings suggested that TPA doesn't act directly through cAMP signal transduction system.

Endothelin-1 induced sustained contractions of tracheal smooth muscle involve an activation of protein kinase C.

Endothelin-1, a potent vasoconstrictor peptide produces concentration dependent contractions in lamb tracheal smooth muscle. These contractions are not inhibited by low doses (up to 20 μM) of trifluoroperazine and W-7, the calmodulin/myosin light chain kinase (MLCK) inhibitors. At higher concentrations (200 μM), a delayed and poor reversal of isometric tensions results. These relaxations are coupled with a partial dephosphorylation of regulatory myosin light chain (MLC). Preincubation of fiber strips in MLCK inhibitors (200 μM) results in a delayed and attenuated contractile response but without a dephosphorylation of MLC. H-7, a putative protein kinase C antagonist (25–100 μM) abolishes endothelin-1 induced contractile effects rapidly (50% relaxation within 1–3 min). Moreover, such relaxations are accompanied by complete dephosphorylation of MLC. Phorbol 12, 13-dibutyrate, an exogenous activator of protein kinase C potentiates the endothelin induced contractions. Inactive phorbol ester, 4α-phorbol ester does not elicit any contractile response in the muscle. The down regulation of protein kinase C, on the other hand suppresses such potentiated contractile responses. These results suggest that endothelin-1 induced contractile tensions in tracheal smooth muscle are mediated by a mechanism that involves an activation of enzyme protein kinase C.

Phorbol Ester Modulates th Action of Acetylcholine in Rabbit Carotid Artery

Authors studied the regulatory mechanism of protein kinase C on the action of acetylcholine in rabbit carotid artery. The arterial rings were myographied isometrically in an isolated organ bath. In this study, acetylcholine relaxed phenylephrine-induced contraction of rabbit carotid artery in the presence of endothelium. In the pretreatment of methylene blue or nitro-L-arginine, the action of acetylchioline was reduced. Pretreatment of phorbol 12-myristate 13-acetate(PMA) attenuated the action of acetylcholine, but PMA did not attenuated it in the presence of staurosporine, suggesting that protein kinase C suppressed the action of acetylcholine. The potency of phorbol ester on the action of acetylcholine was PMA>phorbol 12, 13-dibutyrate(PDBu)>phorbol 12,13-diacetate(PDA), but the direct effect of phorbol on the contraction of arterial rings was PDBu>PMA>PDA. This implied that protein kinase C involved in the contraction of smooth muscle and the attenuation of the action of acetylcholine were different. PMA did not affect on A23187- and sodium nitroprusside-induced vasorelaxation. Acetylcholine increased tissue cGMP contents, which was reduced by PMA. These results suggest that in rabbit carotid artery protein kinase C reduce acetylcholine-stimuated endothelium derived relaxing factor(EDRF) release by affecting membrane receptor, and do not affect on the function of EDRF and cGMP production in the smooth muscle.