Suppression of furylfuramide-induced SOS response by acetophenones using Salmonella typhimurium TA1535/pSK1002 umu test

The recently isolated paeonol (2-hydroxy-4-methoxyacetophenone), as one of the antimutagenic compounds from Discorea japonica, was used as a lead compound for detailed structure-activity relationship studies. Nine acetophenones (2-hydroxy-4-methoxy, 2-hydroxy-5-methoxy, 2-hydroxy-6-methoxy, 4-hydroxy-3-methoxy, o-methoxy, m-methoxy, p-methoxy, and 2,5-dimethoxyacetophenone and acetophenone) were investigated for their ability of suppression of furylfuramide-induced SOS response using Salmonella typhimurium TA1535/pSK1002 in the umu test, against the mutagen, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide). The results showed that 2-hydroxy-6-methoxyacetophenone displayed the strongest activity (EC(50) = 0.6 micromol/mL), and a hydroxyl group at C-2 is necessary feature for acetophenone derivatives to show the suppressive effects of furylfuramide-induced SOS response.     

Suppression of the furylfuramide-induced SOS response by monoterpenoids with a p-menthane skeleton using the Salmonella typhimurium TA1535/pSK1002 Umu test

Suppression of the furylfuramide-induced SOS response by 25 kinds monoterpenoids (hydrocarbons, alcohols, ketones, and aldehydes) with a p-menthane skeleton was studied. Suppression of the SOS-inducing activity by monoterpenoids was determined in the umu test using Salmonella typhimurium TA1535/pSK1002. The terpene alcohols, ketones, and aldehydes had potent suppressive effects, but the hydrocarbons did not. Especially, (+)-menthol, (+)-pulegone, piperitenone, and cuminaldehyde were shown to have the most potent suppressive effects, and the ID(50) (dose for 50% inhibition) was 0.52 micromol/mL.     

Suppression of the SOS-inducing activity of mutagenic heterocyclic amine, Trp-P-1, by triterpenoid from Uncaria sinensis in the Salmonella typhimurium TA1535/pSK1002 Umu test

The methanol extract from Uncaria sinensis showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 3-amino-1,4-dimethyl-5H-pyrido[4,3b]indole (Trp-P-1), which requires liver metabolizing enzymes. The methanol extract from U. sinensis was re-extracted with hexane, CH2Cl2, BuOH, and water, respectively. CH2Cl2 extract showed a suppressive effect. A suppressive compound 1 in CH2Cl2 extract was isolated by SiO2 column chromatography. Compound 1 was identified as ursolic acid by IR, electron ionization EI-MS, and NMR spectroscopy. Suppressive effects of ursolic acid (1) and its derivatives, methyl ursolate (1M), acetylursolic acid (1A), and methyl acetylursolate (1MA), were determined in the umu test. These compounds suppressed 61.3, 37.7, 71.5, and 37.8% of the Trp-P-1-induced SOS response at a concentration of 0.4 micromol/mL, respectively. The ID50 values of compounds 1 and 1A were 0.17 and 0.20 micromol/mL. In addition, these compounds were assayed with the activated Trp-P-1. Suppressive effects on activated Trp-P-1 were decreased as compared with those of Trp-P-1.     

Antimutagenic activity of phenylpropanoids from clove (Syzygium aromaticum)

Phenylpropanoids that possess antimutagenic activity were isolated from the buds of clove (Syzygium aromaticum). The isolated compounds suppressed the expression of the umu gene following the induction of SOS response in the Salmonella typhimurium TA1535/pSK1002 that have been treated with various mutagens. The suppressive compounds were mainly localized in the ethyl acetate extract fraction of the processed clove. This ethyl acetate fraction was further fractionated by silica gel column chromatography, which resulted in the purification and subsequent identification of the suppressive compounds. Electron impact mass spectrometry, IR, and (1)H and (13)C NMR spectroscopy were then used to delineate the structures of the compounds that confer the observed antimutagenic activity. The secondary suppressive compounds were identified as dehydrodieugenol (1) and trans-coniferyl aldehyde (2). When using 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) as the mutagen, compound 1 suppressed 58% of the umu gene expression as compared to the controls at a concentration of 0.60 micromol/mL, with an ID(50) (50% inhibitory dose) value of 0.48 micromol/mL, and compound 2 suppressed 63% of the umu gene expression as compared to the controls at a concentration of 1.20 micromol/mL, with an ID(50) value of 0.76 micromol/mL. Additionally, compounds 1 and 2 were tested for their ability to suppress the mutagenic activity of other well-known mutagens such as 4-nitroquinolin 1-oxide (4NQO) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which do not require liver metabolizing enzymes, and aflatoxin B(1) (AfB(1)) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require liver metabolizing enzymes and activated Trp-P-1 and UV irradiation. Compounds 1 and 2 showed dramatic reductions in their mutagenic potential of all of the aforementioned chemicals or treatment. For the search of the structure-activity relationship, the derivatives of 1 and 2 (1a and 2a-c) were also assayed with all mutagens. Finally, the antimutagenic activities of compounds 1, 1a, 2, and 2a-c against furylfuramide, Trp-P-1, and activated Trp-P-1 were assayed by the Ames test using the S. typhimurium TA100 strain.     

外源乙烯利诱导玉米化学防御作用的时间和浓度效应

为探明外源乙烯利对玉米化学防御作用诱导的浓度和时间效应,本文采用化学和分子生物学相结合的方法,研究了不同浓度乙烯利处理玉米后,叶片乙烯释放量及其合成调控关键基因ACS和ACO表达的变化,典型化感物质丁布的含量及其关键调控基因BX1和BX9表达的变化,以及其他调控次生代谢物的关键基因表达的时间动态。结果表明,外源乙烯利处理玉米12h时,玉米叶片中丁布含量明显增加;24h后,丁布含量反而大量降低,48h后对丁布含量影响不大。外源乙烯利对合成丁布的调控基因BX1没有诱导作用,但处理12h和24h对BX9有明显诱导作用。外源乙烯利处理12h能够使ACS和ACO表达量上升,浓度为40μL·L^-1和60μL·L^-1乙烯利处理使玉米叶片丁布含量大量降低,BX1和BX9的表达量有所下调。外源乙烯利能够使蛋白酶抑制剂MPI表达量升高,且乙烯利浓度越高,诱导作用越明显,但对调控挥发物的FPS和TPS基因表达没有影响。说明外源乙烯利能够启动玉米体内的乙烯途径,诱导玉米启动化学防御过程,但这种作用很可能是负反馈型的。     

Differential characteristics in the chemical composition of bananas from Tenerife (Canary Islands) and Ecuador

The contents of moisture, protein, ash, ascorbic acid, glucose, fructose, total sugars, and total and insoluble fiber were determined in cultivars of bananas (Gran Enana and Peque?a Enana) harvested in Tenerife and in bananas (Gran Enana) from Ecuador. The chemical compositions in the bananas from Tenerife and from Ecuador were clearly different. The cultivar did not influence the chemical composition, except for insoluble fiber content. Variations of the chemical composition were observed in the bananas from Tenerife according to cultivation method (greenhouse and outdoors), farming style (conventional and organic), and region of production (north and south). A highly significant (r = 0.995) correlation between glucose and fructose was observed. Correlations of ash and protein contents tend to separate the banana samples according to origin. A higher content of protein, ash, and ascorbic acid was observed as the length of the banana decreased. Applying factor analysis, the bananas from Ecuador were well separated from the bananas produced in Tenerife. An almost total differentiation (91.7%) between bananas from Tenerife and bananas from Ecuador was obtained by selecting protein, ash, and ascorbic acid content and applying stepwise discriminant analysis. By selecting the bananas Peque?a Enana and using discriminant analysis, a clear separation of the samples according to the region of production and farming style was observed.     

Respiration and growth of a fungus, Mortierella isabellina, in response to grazing by Onychiurus armatus (Collembola)

Colonies of the fungus Mortierella isabellina (Oudem) were grazed by the collembolan Onychiurus armatus (Tullb.) for short periods interrupted by incubation without grazing in laboratory experiments. The grazed fungus had a lower respiration than ungrazed when Collembola were present on the mycelium. Fungal respiration was significantly increased with grazing when Collembola were periodically removed from the mycelium. Metal contamination of the substrate increased fungal respiration, regardless of grazing. Length of fungal mycelium was significantly greater in a natural soil in the presence of Collembola but reduced in a metal-polluted soil. Factors that may determine the impact of grazing on fungi are discussed.     

Isotope labeling studies on the formation of 5-(hydroxymethyl)-2-furaldehyde (HMF) from sucrose by pyrolysis-GC/MS

Although it is generally assumed that the reactivity of sucrose, a nonreducing sugar, in the Maillard reaction is due to its hydrolysis into free glucose and fructose, however, no direct evidence has been provided for this pathway, especially in dry and high temperature systems. Using specifically (13)C-labeled sucrose at C-1 of the fructose moiety, HMF formation was studied at different temperatures. Under dry pyrolytic conditions and at temperatures above 250 degrees C, 90% of HMF originated from fructose moiety and only 10% originated from glucose. Alternatively, when sucrose was refluxed in acidic methanol at 65 degrees C, 100% of HMF was generated from the glucose moiety. Moreover, the relative efficiency of the known HMF precursor 3-deoxyglucosone to generate HMF was compared to that of glucose, fructose and sucrose. Glucose exhibited a much lower conversion rate than 3-deoxyglucosone, however, both fructose and sucrose showed much higher conversion rates than 3-deoxyglucosone thus precluding it as a major precursor of HMF in fructose and sucrose solutions. Based on the data generated, a mechanism of HMF formation from sucrose is proposed. According to this proposal sucrose degrades into glucose and a very reactive fructofuranosyl cation. In dry systems this cation can be effectively converted directly into HMF.     

Determination of linear response in the detection of aroma compounds by atmospheric pressure ionization-mass spectrometry (API-MS)

Linearity and detection thresholds of atmospheric pressure ionization-mass spectrometry (API-MS) were determined for 11 aroma compounds in air at concentrations ranging from 50 ppb to approximately 450 ppm (moles of volatile per mole of air). In most cases, the protonated molecular ion (i.e., m/z = M + 1) was the base peak throughout the range; however, some compounds showed an increase in fragmentation at lower concentrations. Detection limits varied greatly (from 50 ppb to 14 ppm) depending upon the aroma compound being measured. The linear range was also strongly dependent upon the aroma compound, with values ranging from <10-fold change in concentration to >4000-fold change in concentration depending upon the volatile being studied. The two volatiles with poor detection thresholds also exhibited the smallest linear range. Most compounds had linear ranges of >200. There was no apparent relationship between gas-phase basicity and either detection limit or linear range.     

传染性支气管炎病毒青岛腺胃分离株（SD／97／02）核衣壳蛋白基因的序列测定和分析

传染性支气管炎病毒(IBV)为冠状病毒科,冠状病毒属套式病毒目(Nidovirilaes).此病毒可引起鸡急性、高度接触性传染病.IBV的基因组具有先导--引物转录机制,使病毒具有很高的变异率.现已有呼吸型、肾型、肠型和减蛋型.1995年,中国出现一种以腺胃病变为主要特征的鸡传染病,初步鉴定为IBV的又一变异株.IBV的结构蛋白包括纤突蛋白(s1)、基质蛋白(M)和核衣壳蛋白(N).现在大多数研究的重点集中在使机体诱导特异性的中和抗体.纤突蛋白基因s1亚单位上,S1基因的5′末端的高变区(highvariationregion,HVR)的微小变异即可导致毒株之间不能互相保护甚至产生新的组织嗜型.     

Variations in the chemical composition of cassava ( Manihot esculenta Crantz) leaves and roots as affected by genotypic and environmental variation

The purpose of this study was to assess the quality of cassava cultivars, in terms of cyanogenic potential and composition of macro- and micronutrients, sampled from different locations in rural Mozambique. Total cyanide concentrations in fresh cassava tissues were measured using portable cyanide testing kits, and elemental nutrients were later analyzed from dried plant tissue. Variation in cyanogenic potential and nutrient composition occurred both among cultivars and across locations. The majority of cultivars contained >100 ppm total cyanide, fresh weight, and are therefore considered to be dangerously poisonous unless adequately processed before consumption. Leaf cyanogenic and nutrient content varied with plant water status, estimated using carbon isotope discrimination (δ(13)C). The colonization of roots of all cultivars by arbuscular mycorrhizal fungi was also quantified and found to be high, indicating that mycorrhizas could play a key role in plant nutrient acquisition in these low-input farming systems.     

Enhancement in the synthesis of novel feruloyl lipids (feruloyl butyryl glycerides) by enzymatic biotransformation using response surface methodology

Response surface methodology was successfully employed to optimize lipase-catalyzed synthesis of feruloyl butyryl glycerides (FBGs). The effects of the reaction parameters, including the reaction time, reaction temperature, enzyme concentration, substrate molar ratio, and water activity, and the interaction parameters were examined. The analysis suggested that the conversion of the FBGs was significantly (p < 0.05) affected by independent factors of reaction time, reaction temperature, substrate molar ratio, and water activity as well as interactive terms of reaction temperature/reaction time, reaction temperature/enzyme concentration, substrate molar ratio/reaction temperature, water activity/reaction temperature, reaction time/enzyme concentration, and enzyme concentration/water activity. The highest conversion yield of FBGs was 81.2% at the following optimized reaction conditions: reaction temperature of 53.6 degrees C, reaction time of 5.5 days, enzyme concentration of 50.8 mg/mL, water activity of 0.14, and substrate molar ratio of 2.9. The conversion is higher as compared to that at the conditions before optimization.     

Thresholds in selection of breeding habitat by the Eurasian treecreeper (Certhia familiaris)

Assessment of habitat thresholds is a topical issue in ecology, both from theoretical and applied perspectives. We examined how forest structure influences selection of breeding habitat in the Eurasian treecreeper (Certhia familiaris). It is an old-growth forest passerine, which can be considered an umbrella species. Habitat selection data, covering five breeding seasons, were collected from a study area across three spatial scales: (a) territory core scale (a radius of 30 m), (b) territory scale (a radius of 200 m) and (c) large scale (a radius of 500 m). Logistic regression analyses revealed that the radii of 30 and 200 m from the nest were the most important spatial scales for the forest patch occupancy. A loss of forest habitat and a low circumference of stems within the territory decreased the probability of occupancy. There was a distinct threshold in the amount of forest cover on forest patch occupancy when the volume of timber was taken into account. At low timber volumes (0-151 m³/ha) the amount of forest cover was negatively related to the occupancy rate of forest patches. This negative relationship changed abruptly when the volume of timber exceeded 152 m³/ha, after which forest cover had a positive effect on the occupancy rate of forest patches. This is a new way to examine habitat thresholds in relation to forest cover. Furthermore, as debated in recent literature, treecreepers also tend to respond to habitat loss rather than to changes in habitat configuration, which stresses the need for habitat restoration and conservation. Moreover, our results emphasize the importance of within-territory structure over the characteristics of the habitat matrix in selection of breeding habitat.     

CACTFTPPCA1 (YACT)、Dof (AAAG)、MYB可能参与甘蓝型油菜对氮胁迫的响应

  【目的】  油菜需氮量高但氮素利用率低,氮素源库分配效率被认为是调控植物氮素利用效率的关键因子。在拟南芥中,NRT1.7基因介导了植物韧皮部硝酸盐由衰老叶片向幼嫩叶片和角果中的再转运过程。通过分析鉴定油菜中的NRT1.7基因及其对供氮水平的响应,为进一步系统研究NRT1.7基因提供参考依据。  【方法】  以AtNRT1.7基因序列为基础序列,采用生物信息学方法鉴定了白菜、甘蓝和甘蓝型油菜中NRT1.7的同源基因,预测和分析了该基因拷贝数、系统进化、进化选择压力、分子特征、保守基序、跨膜结构域、染色体定位、基因结构及其启动子区域所能结合的顺式作用元件,同时采用荧光定量PCR分析了甘蓝型油菜BnaNRT1.7s的组织表达模式及其对氮胁迫的响应。氮素响应试验以甘蓝型油菜幼苗为材料,在NO₃?-N 9.0 mmol/L溶液中培养10天后,直接测定NRT1.7基因表达量;转入NO₃?-N 0.3 mmol/L 溶液中 (低氮胁迫) 或在无氮溶液中饥饿处理3天后,恢复NO₃?-N 9.0 mmol/L 溶液培养,再测定NRT1.7基因表达量。  【结果】  甘蓝型油菜NRT1.7s家族包含6个成员,系统进化分析表明BnaNRT1.7s与拟南芥进化相似,分布在相近的分支。BnaNRT1.7s家族所有基因成员的Ka/Ks值均小于1.0,受到强烈的纯化选择作用。BnaNRT1.7s家族所有基因成员均属于稳定的两性蛋白,含12～13个跨膜结构域。基因结构相似,均含有3个内含子,且CACTFTPPCA1 (YACT)、Dof (AAAG)、MYB是启动子上丰度较大的顺式作用原件,可能参与了植物对氮素的响应。实时荧光定量PCR结果表明,甘蓝型油菜中NRT1.7基因会受到不同氮素水平的调控。长期 (72 h) 低氮处理,根部BnaA7.NRT1.7b和BnaC6.NRT1.7b基因的表达上调而抑制地上部BnaCn.NRT1.7基因的表达,共同调控植物对低氮胁迫的适应能力。氮饥饿3天后供氮6 h,地上部和根部BnaNRT1.7的基因表达均受到抑制。基因共表达网络分析显示,低氮胁迫下,BnaCn.NRT1.7和BnaC6.NRT1.7b基因分别在地上部和根部氮素再分配中起主导作用。  【结论】  甘蓝型油菜NRT1.7蛋白进化过程相对保守,基因结构相似,启动子上的顺式作用原件CACTFTPPCA1 (YACT)、Dof (AAAG)、MYB可能参与了甘蓝型油菜对氮胁迫的响应。     

Effect of soil bacteria on the ability of polycyclic aromatic hydrocarbons (PAHs) removal by Trametes versicolor and Irpex lacteus from contaminated soil

The effect of bacteria represented by indigenous soil microflora or a mixture of soil bacteria Pseudomonas aeruginosa and Rhodococcus erythropolis on fungal growth, extracellular enzyme production and polycyclic aromatic hydrocarbons (PAHs) biodegradation efficiency in soil of white-rot fungi Trametes versicolor and Irpex lacteus was investigated. Both fungi were able to colonize soil. The growth yields measured by ergosterol were about two-fold in I. lacteus after 10 weeks. Laccase was produced in T. versicolor cultures in the presence or absence of bacteria but live bacteria reduced the laccase levels in soil about 5 times. Manganese-dependent peroxidase (MnP) was not detected in T. versicolor cultures. The amounts of MnP and laccase in I. lacteus cultures were not affected by the presence of bacteria. T. versicolor was more efficient in PAH removal for all PAHs tested although its capacity to colonize soil was lower. The removal rates of PAHs by T. versicolor in sterile soil were 1.5-fold, 5.8-fold and 1.8-fold for 2-3-ring, 4-ring and 5-6-ring PAHs, compared to I. lacteus, respectively. I. lacteus showed a low efficiency of removal of pyrene, benzo[a]anthracene and benzo[k]fluoranthene, compared to T. versicolor, whereas chrysene and benzo[b]fluoranthene were degraded by neither fungus. The main effect of the presence of the indigenous microflora or R. erythropolis and P. aeruginosa was a significant decrease of degradation of total PAHs by both T. versicolor and I. lacteus. Weak fungal/bacterial synergistic effects were observed in the case of removal of acenapthylene, benzo[a]pyrene, dibenzo[a,h]anthracene and benzo[g,h,i]perylene by I. lacteus and acenapthylene by T. versicolor. However, the bacterial effects were different in the two fungi. PAH abiotic losses represented 15 and 21% of the total PAHs after 5 and 10 weeks, respectively; naphthalene and acenaphthene were removed from the soil due to volatilization.     

Pollination of the invasive exotic shrub Lupinus arboreus (Fabaceae) by introduced bees in Tasmania

Exotic plant invasions threaten ecological communities world-wide. Some species are limited by a lack of suitable pollinators, but the introduction of exotic pollinators can facilitate rapid spread. In Tasmania, where many non-native plants are naturalised, exotic honeybees (Apis mellifera) and bumblebees (Bombus terrestris) have become established. We determined how these species affect the pollination of Lupinus arboreus, an invasive, nitrogen-fixing shrub, which is rarely visited by native pollinators. The proportion of flowers setting seed and the number of ovules fertilised per flower were positively related to the visitation rates of both exotic bee species. There was no effect of bee visitation rates on the proportion of seeds aborted prior to maturity, possibly due to post-fertilisation environmental constraints. We conclude that the spread of B. terrestris may not alter the fecundity of L. arboreus because of the pollination service provided by A. mellifera, and discuss potential interactions between these two bee species.     

Ecology of soil springtails (Collembola, Insecta) from pine woods and Rhododendron shrublands in the Central and Eastern Pyrenees (North Spain)

The collembological composition of samples from the Central and Western Pyrenees (Northern Spain) was studied. Soils from two biotopes (pine forest and Rhododendron shrub) were studied in Nuria and Vallibierna, using different diversity indices and multivariate analyses. Ten species were found that were endemic to the Iberian Peninsula. Three of these are exclusive to the Pyrenees: Ceratophysella elegans, Hypogastrura dasiensis and Protachorutes pyrenaeus. The greatest diversity was observed in the soils of Rhododendron, above all at Nuria. Collembola were most poorly represented in the pine forest of Vallibierna, where the endemic Hypogastrura meridionalis was the dominant species. Multivariate analyses indicated that the latter species characterizes this pine forest and separates it from all other biotopes studied. The evenness (E) was most pronounced in Nuria, where Folsomia manolachei was the characteristic species.     

Do Ural owls (Strix uralensis) suffer from the lack of nest sites in managed forests?

Nest site availability, preferences and quality for Ural owls (Strix uralensis) were studied in managed forests and a large nature reserve in Estonia. The owl's density was relatively higher in the reserve. Ural owls bred in tree cavities and stick nests, but preferred the cavities. Suitable cavities were very rare compared to stick nests, and most cavities were found in the reserve. Pairs having no suitable cavities in their territories started to breed less frequently, but no difference was detected in young produced per breeding attempt between cavity nests and stick nests. Used cavities and stick nests as well as unused stick nests were situated in similar stands and landscapes, but nest tree and nest characteristics of cavity nests were distinct. The study shows that in managed forests the lack of large snags and tree cavities may limit the numbers of Ural owls, which accept these structures for breeding more readily than stick nests. Retention of large cavity-forming trees in forestry operations may be an effective conservation strategy for this species.     

嗜水气单胞菌外膜蛋白（OMP）的原核表达及其对BALB/c小鼠的免疫保护研究

为确定嗜水气单胞菌(Aeromonas hydrophila,Ah)AS1.927株外膜蛋白(OMP)的原核表达产物是否具有抗原性及其对小鼠的免疫保护力.本研究根据GenBank上嗜水气单胞菌外膜蛋白ompA基因序列(GenBank登录号:AF146597)设计1对引物,克隆出ompA全长基因1020 bp(GenBank登录号:EU309491),经Sal Ⅰ和Xhol Ⅰ双酶切后连接pET-30a(+),转化大肠杆菌(Escherichia cDli)BL21,IPTG诱导表达,并进行SDS-PAGE及Westernblot分析鉴定.结果显示重组基因工程菌E.coli[pET-30a-ompA]表达的融合蛋白分子量约为40.7kD,可以被鼠抗嗜水气单胞菌外膜蛋白抗血清识别.将重组基因工程菌Ecoli[pET-30a-om-pA]口服免疫BALB/c小鼠(Mus mussulus);末次免疫1周后用放射免疫分析小鼠肠粘膜分泌型免疫球蛋白A(sIgA)水平,检测结果揭示,该重组基因工程菌能提高sIgA的分泌(P<0.05);同时在小鼠血清中测出特异性抗体IgG(P<0.05).末次免疫2周后用100 LD50的Ah AS1.927(3.3×105> cfu/mL)腹腔注射攻击小鼠,口服重组菌对小鼠的相对免疫保护力(relative percent survival,RPS)为75%,表明重组基因工程菌可诱导小鼠对AhAS1.927产生一定的免疫保护作用.     

Generation of decarboxylated and dehydrogenated betacyanins in thermally treated purified fruit extract from purple pitaya (Hylocereus polyrhizus) monitored by LC-MS/MS

Pigments of purple pitaya [Hylocereus polyrhizus (F.A.C. Weber) Britton and Rose] fruits were submitted to extraction and were decarboxylated during heating experiments in acidified ethanolic and aqueous solutions. Groups of betacyanins with different decarboxylation levels were identified in the heating products by LC-DAD and LC-MS/MS. The main decarboxylation products were 2-decarboxy-betacyanins, 17-decarboxy-betacyanins, and 2,17-bidecarboxy-betacyanins. The structures of other compounds were assigned to 2,15,17-tridecarboxy-betacyanins and 14,15-dehydrogenated derivatives (neo-derivatives) of all decarboxylated betacyanins found.