Evaluation of Characteristic Aroma Compounds of Citrus natsudaidai Hayata (Natsudaidai) Cold-Pressed Peel Oil

The characteristic aroma compounds of Citrus natsudaidai Hayata essential oil were evaluated by a combination of instrumental and sensory methods. Sixty compounds were identified and quantified, accounting for 94.08% of the total peel oil constituents. Limonene was the most abundant compound (80.68%), followed by γ-terpinene (5.30%), myrcene (2.25%) and α-pinene (1.30%). Nineteen compounds which could not be identified in the original oil were identified in the oxygenated fraction. Myrcene, linalool, α-pinene, β-pinene, limonene, nonanal, γ-terpinene, germacrene D, and perillyl alcohol were the active aroma components (FD-factor > 3⁶), whereas β-copaene, cis-sabinene hydrate and 1-octanol were suggested as characteristic aroma compounds, having a Natsudaidai-like aroma in the GC effluent. Three other compounds, heptyl acetate, (E)-limonene oxide and 2,3-butanediol, which each showed a high RFA value (>35) were considered to be important in the reconstruction of the original Natsudaidai oil from pure odor chemicals. The results indicate that 1-octanol was the aroma impact compound of C. natsudaidai Hayata peel oil.     

Volatile Compounds of Bacterial Origin: Structure,Biosynthesis, and Biological Activity

Microbiology - Microorganisms produce various volatile compounds, including volatile organic compounds and complex combinations of volatile compounds. The ecological and functional role of these...     

MPTA对柑橘果皮类胡萝卜素形成的影响

以宽皮柑橘“本地早”为试材 ,研究了 2 (4 甲基苯氧 )三乙基胺 (MPTA)处理对柑橘果实外观颜色的影响 ,并探讨其与相关类胡萝卜素消长的关系及与糖含量变化的可能联系。结果表明 :MPTA处理促进柑橘果皮组织中类胡萝卜素 (主要为番茄红素 )的生物合成 ,使果皮颜色由淡橙黄色转为红色 ;随着番茄红素的积累 ,其上游前体物质葡萄糖含量下降 ,而其下游产物β 隐黄质、玉米黄素的合成不受影响     

早熟金柚果皮挥发油的提取及GC-MS分析

采用水蒸气蒸馏法提取早熟金柚果皮挥发油,通过正交实验优选获得早熟金柚果皮挥发油提取的工艺参数,结果表明：早熟金柚果皮挥发油的最佳提取工艺是将柚皮粉碎60 s,加水5倍,提取6 h。采用GC-MS联用技术对早熟金柚果皮挥发油的化学成分进行分离鉴定,共分离出44个峰,鉴定出了其中的25种化合物,占峰面积的98.43%。用面积归一化法测定了各个组分的相对百分含量,其主要成分有柠檬烯（65.82%）、β-月桂烯（25.52%）、4-侧柏烯（1.78%）、紫苏烯（0.44%）、氧化芳樟醇（0.42%）。     

印度酸桔与飞龙枳属间体细胞杂种的胞质遗传分析

对印度酸桔（Citrus reticulata） 飞龙枳（Poncirus trifoliata）属间体细胞杂种的3棵8年生植株及其融合亲本的胞质基因组进行了CAPS（Cleaved Amplified Polymorphic Sequences）和RFLP分析。用5对叶绿体和5对线粒体通用引物对（universal primer pairs）对杂种及亲本的总DNA进行PCR扩增,都没有检测到多态性,但扩增产物分别用11种限制性内切酶酶切后,发现3个有多态性的叶绿体CAPS标记和1个线粒体CAPS标记。结果表明杂种的叶绿体都来源于飞龙枳,而线粒体都来源于印度酸桔。为了证实CAPS分析结果的可靠性,用5种限制性内切酶对总DNA进行单酶切,分别与1个叶绿体探针和5个线粒体探针杂交,结果与CAPS分析一致。初步证实该组合体细胞杂种的胞质遗传组成为“印度酸桔的线粒体 飞龙枳的叶绿体”。结果表明细胞融合确实能导致细胞核、线粒体和叶绿体的重新组合,为柑桔体细胞杂种中线粒体偏向来源于悬浮亲本而叶绿体偏向来源于叶肉亲本的胞质分配现象提供了新的证据,并为通过体细胞融合技术定向转移柑桔胞质基因的品种改良思路提供了重要理论依据。     

The Quantitative Growth of Young Seedlings of the Citrus Rootstocks Citrus sinensis (L.) Osbeck, Poncirus trifoliata (L.) Raf. and their hybrid, Carrizo citrange

An 18 months' growth analysis of three citrus rootstocks revealedconsiderable differences in absolute and relative growth-ratesand in the allometric growth of leaf, stem, thorn, and root. Over the whole period the order of the average absolute growth-rateswas citrange > sinensis > trifoliata, and of the relativegrowth-rates citrange > sinensis = trifoliata. Although sinensisachieved the highest R.G.R. this was maintained over a shortperiod only. Sinensis had relatively most leaf, trifoliata moststem, and citrange most root. The deciduousness of trifoliataproduced only an intermittent deviation in the allometric line,the leaf proportion returning to the average course within afew weeks of the start of spring growth. The time course of these changes was not sufficiently regularfor phases of maximum growth to be characterized. During thewinter period of minimum growth there was a loss in weight ofthe roots (in sinensis, and trifoliata) and stem (citrange).     

Molecular characterization of cytoplasmic and nuclear genomes in phenotypically abnormal Valencia orange (Citrus sinensis) + Meiwa kumquat (Fortunella crassifolia) intergeneric somatic hybrids

Organelle DNA inheritance of four 10-year-old somatic hybrid trees between Valencia orange [Citrus sinensis (L.) Osbeck] and Meiwa kumquat (Fortunella crassifolia Swingle) was analyzed by cleaved amplified polymorphic sequence (CAPS) and restriction fragment length polymorphisms (RFLPs). Five chloroplast (cp) and three mitochondrial (mt) universal primer pairs were amplified, but no polymorphisms were detected. When the polymerase chain reaction products were digested by 15 restriction enzymes, four polymorphic cpDNA-CAPS and two mtDNA-CAPS markers were found. Both the cpDNA and mtDNA in the somatic hybrids were derived from Valencia orange (the embryogenic suspension parent). Genomic DNA of the somatic hybrids and corresponding parents was digested by five restriction endonucleases and hybridized with one chloroplast probe (RbcL- RbcL) and nine mitochondrial probes (coxI, coxII, c oxIII, c ob, atpA, tyr, proI, atp6 and atp9). The results indicated that three hybrid plants shared one strong cpDNA band with both parents and that the remaining one plant had two additional novel bands besides the shared band, while their mtDNA was identical to that of Valencia orange plus non-parental bands. When data on the mtDNA banding patterns were combined with observations on phenotypic performance in the field, it was found that the more complex mtDNA banding pattern coincided with increased vigor of the plant. The stability of the organelle genomes was studied by extracting the genomic DNA of one hybrid plant at monthly intervals for 1 year and then analyzing it using RFLPs. Before the dieback of the shoots, two fragments of the mtDNA were lost while the cpDNAs remained stable. Ploidy analysis by flow cytometry showed that all of the hybrids were stable tetraploids. Four simple sequence repeat primer pairs were applied to detect microsatellite alleles of the four hybrid plants, both parents and the 12 DNA samples from one plant. The results showed that all hybrids had biparental bands uniformly, which indicated that they had the same nuclear background. These results suggest that the mtDNA pattern is correlated with the phenotypic abnormality of Valencia and kumquat somatic hybrid plants and that nuclear-cytoplasm incompatibility may be the cause of dieback.     

Refinement of the Citrus Tristeza Virus Resistance Gene (Ctv) Positional Map in Poncirus trifoliata and Generation of Transgenic Grapefruit (Citrus paradisi) Plant Lines with Candidate Resistance Genes in this Region

Citrus tristeza virus (CTV) is a major pathogen of Citrus. A single dominant gene Ctv present in the trifoliate relative of Citrus, Poncirus trifoliata confers broad spectrum resistance against CTV. Refinement of genetic maps has delimited this gene to a 121 kb region, comprising of ten candidate Ctv resistance genes. The ten candidate genes were individually cloned in Agrobacterium based binary vector and transformed into three CTV susceptible grapefruit varieties. Two of the candidate R-genes, R-2 and R-3 are exclusively expressed in transgenic plants and in Poncirus trifoliata, while five other genes are also expressed in non-transformed Citrus controls. Northern blotting with a CTV derived probe for assessment of infection in virus inoculated plants over a span of three growth periods, each comprising of six to eight weeks, indicates either an absence of initiation of infection or it’s slow spread in R-2 plant lines or an initial appearance of infection and it’s subsequent obliteration in some R-1 and R-4 plant lines. Limited genome walk up- and downstream form R-1 gene, based on it’s 100% sequence identity between Poncirus and Citrus, indicates promoter identity of 92% between the two varieties. Further upstream and downstream sequencing indicates the presence of an O-methyl transferase and a Copia like gene respectively in Citrus instead of the amino acid transporter like gene upstream and a sugar transporter like gene downstream in Poncirus. The possibility of recombinations in the resistance locus of Citrus and the need for consistent monitoring for virus infection and gene expression in the transgenic Citrus trees is discussed. Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.     

丙酮体系中柑橘皮中类胡萝卜素与VC及VE的协同抗氧化性研究

研究了避光条件下柑橘皮类胡萝止素提取物与VC及VE在丙酮溶剂体系中的协同抗氧化性,初步探讨了协同效应产生的条件以及机理。结果表明,在VC浓度为100mg／mL,类胡萝卜素起始浓度与VC浓度的比值小于或等于0．05时,或、VE浓度为O．384mg／mL,类胡萝卜素起始浓度与、VE浓度的比值小于或等于1．5时,类胡萝卜素与VC或、VE在丙酮体系中存在显著的助氧化作用;当体系中VC或VE浓度较低时,随反应时间延长,VC或VE可促进类胡萝卜素的氧化降解。     

Morphology and Volatile Compounds of Metathoracic Scent Gland in Tessaratoma papillosa (Drury) (Hemiptera: Tessaratomidae)

Tessaratoma papillosa (Drury) (Hemiptera: Tessaratomidae) is a serious insect pest of litchi and longan in South China. When disturbed, this insect could release large quantities of disagreeable odorous volatiles from its scent gland. Knowledge on the scent gland and its secretion is crucial for developing the semiochemical methods to manage this pest. Morphology and ultrastructure of the metathoracic scent glands (MTGs) were studied under stereo and scanning electron microscopy, and the volatile compounds of MTGs from both male and female T. papillosa were analyzed with coupled gas chromatography?Cmass spectrometry (GC?CMS). The MTG complex is located between the metathorax and the first abdominal segment at the ventral surface of the insect, which has a well-developed single double valve cystic-shaped orange median reservoir, paired colorless lateral glands in both sides, and a long and wavy tubular accessory gland that inlays tightly into the ventral edge around the median reservoir. The MTG opens to the body surface through paired ostioles located between the meso- and metacoxae of the evaporatorium with mushroom bodies. The GC?CMS analyses showed that female and male adults have nine major volatile components in common. Tridecane is the most abundant in both females and males, reaching up to 47.1% and 51.8% of relative amount, respectively. The minor component is benzophenone with only 0.28% and 0.14%. Furthermore, undecane, tetradecane, 3-methyl-tridecane, and cyclopentadecane were found only in males. The possible function of volatile compounds of MTG contents in T. papillosa is addressed.     

Volatile flavor components of ripe and overripe ki-mikans (Citrus flaviculpus Hort. ex Tanaka) in comparison with Hyuganatsu (Citrus tamurana Hort. ex Tanaka)

The volatile flavor components of ripe and overripe ki-mikan (Citrus flaviculpus Hort. ex Tanaka) peel oil samples, which had been isolated by cold-pressing, were investigated by capillary GC and GC-MS, and compared with the Hyuganatsu (Citrus tamurana Hort. ex Tanaka) flavor. Limonene (ripe fruit, 82.44%; overripe fruit, 73.10%) was the most abundant compound in the ki-mikan oil, this being followed by gamma-terpinene (8.83% and 13.74%), trans-beta-farnesene (1.76% and 3.12%) and myrcene (1.54% and 1.13%). The composition of overripe ki-mikan oil was characterized by higher amounts of aliphatic and sesquiterpene hydrocarbons, monoterpene and sesquiterpene alcohols, ketones and esters than that of ripe ki-mikan oil. Monoterpene hydrocarbons, especially limonene (84.78%), were predominant in Hyuganatsu oil. The CPO composition of ki-mikan was qualitatively similar to that of Hyuganatsu, but differed quantitatively. The content of sesquiterpene hydrocarbons was higher in the ki-mikan oil samples than in Hyuganatsu oil, while ketones showed the opposite predominance. These differences were more evident in the trans-beta-farnesene and l-carvone contents. The ratio of both these compounds could be used to distinguish ki-mikan oil from Hyuganatsu oil.     

抱茎蓼挥发油成分及其抗菌活性的研究

水蒸气蒸馏法从抱茎蓼全草中提取挥发油,用气相色谱-质谱联用技术对其挥发油组分进行分离和鉴定,运用气相色谱面积归一化法确定各组分的相对含量,并利用正构烷烃系列物质对各组分进行定性确定,从抱茎蓼全草的挥发油中检出41个组分,占全油的99.21%,鉴定出38个组分,其主要组分是石竹烯(16.98%)、3-己烯-1-醇(14.69%)、3-辛烯-3醇(8.89%)、a-里哪醇(7.13%)、β-环柠檬醛(6.36%)等。对抱茎蓼全草的挥发油做了抗菌试验,其挥发油对大肠埃希菌(ATCC25922株)、肠炎沙门菌(50040株)、金黄色葡萄球菌(ATCC25925株)有显著地抑制和灭活作用。     

Chemotaxonomic study of the genusTabernaemontana (Apocynaceae) based on their indole alkaloid content

According to their alkaloidal products species of the new genusTabernaemontana can be partly differentiated. This differentiation is in agreement with the old genera classification. From the chemotaxonomic point of view a subdivision of subfam.Plumerioideae of theApocynaceae is proposed.     

Influence of Mn Deficiency on Growth,Chlorophyll Content,Physiology, and Essential Monoterpene Oil(s) in Genotypes of Spearmint (Mentha Spicata L.)

At various intervals after inoculation of the roots of groundnut plants with the fungus Macrophomina phaseoli, ¹⁴CO₂ was administered to branch 2 (from the base) of the plants in the light. The effects of the disease on the translocation of ¹⁴C-photosynthates out of the source branch to the rest of the plant were studied 24 h after labelling. As the plant aged and the disease symptom development became more evident, an increasing percentage of the fixed ¹⁴C-photosynthates was exported from branch 2 of the inoculated plants (IP) compared to the non-inoculated plants (NIP). The apex, main stem, and branch 1 of NIP imported more of the total fixed ¹⁴C throughout the developmental stages of the plant except for day 10 after inoculation when branch 1 of IP imported almost 76 % of the total fixed ¹⁴C. The roots of IP were the major sink and imported higher percent of the total fixed ¹⁴C than the roots of NIP. This revised version was published online in August 2006 with corrections to the Cover Date.     

Nematicidal Activity of Cassia and Cinnamon Oil Compounds and Related Compounds toward Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae)

The nematicidal activity of two cassia, Cinnamomum cassia, oils (Especial and true), four cinnamon, Cinnamomum zey-lanicum, oils (technical, #500, bark and green leaf), and their compounds (e.g., trans-cinnamaldehyde and trans-cinnamic acid) toward adult Bursaphelenchus xylophilus was examined by a direct contact bioassay. Results were compared with those of 34 related compounds. As judged by 24-hour LC₅₀ values, two cassia oils (0.084–0.085 mg/ml) and four cinnamon oils (0.064–0.113 mg/ml) were toxic toward adult B. xylophilus. Of 45 test compounds, trans-cinnamaldehyde (0.061 mg/ml) was the most active nematicide, followed by ethyl cinnamate, α-methyl-trans-cinnamaldehyde, methyl cinnamate and allyl cinnamate (0.114–0.195 mg/ml). Potent nematicidal activity was also observed with 4-methoxycinnamonitrile, trans-4-methoxycinnamaldehyde, trans-2-methoxy-cinnamaldehyde, ethyl α-cyanocinnamate, cinnamonitrile and cinnamyl bromide (0.224–0.502 mg/ml). Structure-activity relationships indicate that structural characteristics, such as types of functional groups, saturation and carbon skeleton, appear to play a role in determining the toxicities to adult B. xylophilus. Cassia and cinnamon oils and test compounds described merit further study as potential nematicides or leads for the control of pine wilt disease caused by B. xylophilus.     

代代花挥发油的超临界萃取及其在烟草中的应用

为了开发新的天然烟用香料,采用超临界流体萃取技术萃取代代花并优化了萃取工艺,GC-MS对挥发油成分进行了分离鉴定,并对其进行了卷烟加香试验.结果表明:①超临界萃取代代花的最佳工艺为:萃取压力40 MPa、萃取温度50℃萃取时间15 min、改性剂为20%乙醇;②代代花挥发油中共鉴定出45种挥发性成分,主要成分为柠檬烯、...     

The Genetic Structure of an Invasive Pest,the Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae)

The Asian citrus psyllid Diaphorina citri is currently the major threat to the citrus industry as it is the vector of Candidatus Liberibacter, the causal agent of huanglongbing disease (HLB). D. citri is native to Asia and now colonizes the Americas. Although it has been known in some countries for a long time, invasion routes remain undetermined. There are no efficient control methods for the HLB despite the intensive management tools currently in use. We investigated the genetic variability and structure of populations of D. citri to aid in the decision making processes toward sustainable management of this species/disease. We employed different methods to quantify and compare the genetic diversity and structure of D. citri populations among 36 localities in Brazil, using an almost complete sequence of the cytochrome oxidase I (COI) gene. Our analyses led to the identification of two geographically and genetically structured groups. The indices of molecular diversity pointed to a recent population expansion, and we discuss the role of multiple invasion events in this scenario. We also argue that such genetic diversity and population structure may have implications for the best management strategies to be adopted for controlling this psyllid and/or the disease it vectors in Brazil.     

Identification of the Volatile Compounds Produced in Sterile Fish Muscle (Sebastes melanops) by Pseudomonas fragi

Volatile compounds produced by Pseudomonas fragi strain 18 in sterile fish muscle (Sebastes melanops) were identified by combined gas-liquid chromatography and mass spectrometry. Compounds positively identified included dimethyl sulfide, acetaldehyde, ethyl acetate, ethyl alcohol, and dimethyl disulfide. Methyl mercaptan, ethyl butyrate, ethyl hexanoate, and butanone were tentatively identified by relative retention times of the authentic compounds. The fruity odor that developed in fish muscle during incipient spoilage was attributed to a synergistic flavor interaction involving the ethyl esters of acetate, butyrate, and hexanoate.     

Genetic Differentiation,Niche Divergence,and the Origin and Maintenance of the Disjunct Distribution in the Blossomcrown Anthocephala floriceps (Trochilidae)

Studies of the origin and maintenance of disjunct distributions are of special interest in biogeography. Disjunct distributions can arise following extinction of intermediate populations of a formerly continuous range and later maintained by climatic specialization. We tested hypotheses about how the currently disjunct distribution of the Blossomcrown (Anthocephala floriceps), a hummingbird species endemic to Colombia, arose and how is it maintained. By combining molecular data and models of potential historical distributions we evaluated: (1) the timing of separation between the two populations of the species, (2) whether the disjunct distribution could have arisen as a result of fragmentation of a formerly widespread range due to climatic changes, and (3) if the disjunct distribution might be currently maintained by specialization of each population to different climatic conditions. We found that the two populations are reciprocally monophyletic for mitochondrial and nuclear loci, and that their divergence occurred ca. 1.4 million years before present (95% credibility interval 0.7–2.1 mybp). Distribution models based on environmental data show that climate has likely not been suitable for a fully continuous range over the past 130,000 years, but the potential distribution 6,000 ybp was considerably larger than at present. Tests of climatic divergence suggest that significant niche divergence between populations is a likely explanation for the maintenance of their disjunct ranges. However, based on climate the current range of A. floriceps could potentially be much larger than it currently is, suggesting other ecological or historical factors have influenced it. Our results showing that the distribution of A. floriceps has been discontinous for a long period of time and that populations exhibit different climatic niches have taxonomic and conservation implications.