Heterochromatin type, amount and distribution in wild species of chili peppers (Capsicum, Solanaceae)

Triple staining with the fluorochromes chromomycin A3, distamycin A and 4′-6-diamidino-2-phenylindole (CMA/DA/DAPI) was applied to somatic metaphases and interphase nuclei of 11 taxa of wild chili peppers (Capsicum), with 2n = 2x = 24 (C. annuum var. glabriusculum, C. cardenasii, C. chacoense, C. flexuosum, C. galapagoense, C. eximium, C. praetermissum and C. tovarii) and 2n = 2x = 26 (C. recurvatum, C. rhomboideum and C. villosum) to analyse heterochromatin type, amount and distribution in wild members of this genus. Heterochromatic banding patterns allowed the identification of all the taxa examined and contributed to their taxonomic grouping. GC-rich heterochromatin (CMA+/DAPI?) was typical in all taxa; only C. praetermissum possessed also AT-rich (CMA?/DAPI+) and mixed GC- and AT-rich (CMA+/DAPI+) bands. Heterochromatin amount (expressed as % of karyotype length) ranged between 1.72 (C. chacoense) and 16.82 (C. flexuosum) and was positively correlated with karyotype length in most of the taxa examined. Heterochromatin located mainly at terminal position of chromosomes but intercalary position prevailed in C. flexuosum. Nucleolus organizer regions (NOR)-associated GC-rich heterochromatin was exclusively terminal and included the distal macrosatellite and a small portion on the corresponding arm. In all the taxa analysed, an equilocal heterochromatin distribution in non-homologous chromosomes of karyotype was observed, suggesting concerted evolution of heterochromatin dispersion in Capsicum.     

New cysteine-S-conjugate precursors of volatile sulfur compounds in bell peppers (Capsicum annuum L. cultivar)

The objective of this study was to verify whether the volatile organic sulfur compounds recently discovered in bell pepper (Capsicum annuum, L. cultivars), such as the mercapto-ketones: 4-sulfanyl-2-heptanone and 2-sulfanyl-4-heptanone, the mercapto-alcohols: 4-sulfanyl-2-heptanol and 2-sulfanyl-4-heptanol, and heptane-2,4-dithiol, originate from their corresponding cysteine-S-conjugates. Analysis of aqueous extracts of red and green bell pepper by ultraperformance liquid chromatography-mass spectrometry with electrospray ionization in the positive mode (UPLC-MS ESI(+)) displayed masses corresponding to the expected cysteine-S-conjugates. To confirm this observation, four cysteine-S-conjugates were prepared as authentic samples: S-(3-hydroxy-1-methylhexyl)-L-cysteine, S-(3-hydroxy-1-propylbutyl)-L-cysteine, S-(3-oxo-1-propylbutyl)-L-cysteine, and (2R,2'R)-3,3'-(4-hydroxyheptane-2,6-diyl)bis(sulfanediyl) bis(2-aminopropanoic acid). By comparison with the fragmentation patterns and retention times of synthetic mixtures of cysteine-S-conjugate diastereoisomers, the natural occurrence of cysteine conjugates was confirmed in bell peppers. In addition, the cysteine-S-conjugates from red and green bell pepper extracts were concentrated by ion exchange chromatography and the fractions incubated with a β-lyase (apotryptophanase). The liberated thiols were concentrated by affinity chromatography, and their occurrence, detected by gas chromatography-mass spectrometry, confirmed our predictions. Moreover, 3-sulfanyl-1-hexanol was also detected and the occurrence of S-(1(2-hydroxyethyl)butyl)-L-cysteine confirmed. A quantitative estimation based on external calibration curves, established by UPLC-MS ESI(+) in selected reaction monitoring mode, showed that cysteine-S-conjugates were present at concentrations in the range of 1 to 100 μg/kg (±20%).     

Efficiency of fertilizer formulation,stock solution volume and media on chili (Capsicum annum kulai F1)

The growth of the greenhouse chili industry is rapidly increasing in the world including Malaysia. Currently, compost is the most popular growing media. Four fertilizer formulations commonly used by farmers (Local), including the recommended Cooper, Bennoit and Cooper Modified formulation, were evaluated in combination with two volumes (400 and 750 L) for enhancement fruit yield of chili in soilless culture. The results indicate that, the day of blooming and fruiting was reduced by 91% and 50% in media containing coconut dust (CD) + empty fruit bunch (EFB) compared with CD alone. Yield with CD+EFB was increased 36% compared with CD while volume of water shows insignificant difference. Interestingly, Cooper, Local and Cooper Modified formulation enhanced 32, 28 and 19% of yield, respectively. As conclusion, combination of CD+EFB with Cooper, Local and Cooper Modified were more efficient in yield production compared with CD alone for future research.     

New volatile sulfur-containing constituents in a simultaneous distillation-extraction extract of red bell peppers (Capsicum annuum)

An extract of red bell peppers ( Capsicum annuum) was prepared by simultaneous distillation-extraction (SDE, Likens-Nickerson). In addition to the already known (3 E)-3-hepten-2-one ( 1), the unsaturated C9-ketones 1-nonen-4-one ( 2), (2 E)-2-nonen-4-one ( 3), and (2 E,5 E)-2,5-nonadien-4-one ( 4), 2-methoxy-3-isobutylpyrazine ( 5), and heptane-2-thiol ( 6), we identified 19 new thiols (the aliphatic saturated and unsaturated thiols 14- 16, and 22- 27, the mercapto-ketones 12 and 13, the mercapto-alcohols 17, 18, and 30, the dithiols 19 and 28, the methylthio-thiols 20 and 21, and the thiophene-thiol 31) and the two new dithiolanes 10 and 29. All of them are structurally related to the unsaturated C7- and C9-ketones 1- 4. The free thiols were enriched using Affi-Gel 501 ( p-aminophenyl-mercuric acetate grafted on an agarose gel). The new compounds were confirmed by syntheses and were organoleptically evaluated.     

Difference in folate content of green and red sweet peppers (Capsicum annuum) determined by liquid chromatography-mass spectrometry

Folic acid (pteroylmonoglutamic acid) is used in enriched foods; however, very little folic acid occurs naturally in fruits and vegetables. For the U.S. Department of Agriculture's National Food and Nutrient Analysis Program, a number of fruits and vegetables have been assayed for endogenous folates, by a liquid chromatography-mass spectrometry method, to evaluate the accuracy of existing data for total folate determined by standard microbiological analysis. Folate in red and green sweet peppers (Capsicum annuum) differed notably (70.2 and 20.7 microg/100 g, respectively) and exceeded existing values determined by microbiological assay (18 and 11 microg/100 g, respectively). 5-Methyltetrahydrofolate was the predominant vitamer, but a significant amount of 5-formyltetrahydrolfolate and some 10-formylfolate were present. These findings may assist in making dietary recommendations or developing research diets related to folate. The data from this study have been used to update the folate values in release 19 of the USDA Nutrient Database for Standard Reference.     

Carotenoid composition in the fruits of red paprika (Capsicum annuum var. lycopersiciforme rubrum) during ripening; biosynthesis of carotenoids in red paprika

The changes in the carotenoid pigments of the Capsicum annuum var. lycopersiciforme rubrum during maturation have been investigated quantitatively by means of a HPLC technique. In all of the chromatograms, 40 peaks were detected; 34 carotenoids were identified. The total carotenoid content of the ripe fruits was about 1.3 g/100 g of dry weight, of which capsanthin constituted 37%, zeaxanthin was 8%, cucurbitaxanthin A was 7%, capsorubin constituted 3.2%, and beta-carotene accounted for 9%. The remainder was composed of capsanthin 5,6-epoxide, capsanthin 3,6-epoxide, 5,6-diepikarpoxanthin, violaxanthin, antheraxanthin, beta-cryptoxanthin, and several cis isomers and furanoid oxides. The possible biosynthetic routes for the formation of minor carotenoids containing 3,5,6-trihydroxy-beta-, 3,6-epoxy-beta-, and 6-hydroxy-gamma-end groups are described.