Effect of leucine on aroma volatiles production from Ceratocystis fimbriata grown in liquid culture

Aroma volatiles produced by Ceratocystis fimbriata on a defined liquid synthetic medium with and without the addition of leucine were identified by gas chromatography–mass spectrometry and quantified by gas chromatography-flame ionisation detection in the liquid medium as well as in the headspace. Volatiles were extracted from the liquid by simultaneous steam distillation–solvent extraction. Ceratocystis fimbriata produced a complex set of volatile intermediary metabolites, of which ethanol was the dominant compound (92–95% of total volatiles). Low molecular weight esters, alcohols, aldehydes, ketones, alkanes, and carboxylic acids were identified in the liquid broth. Alcohols and esters were the most abundant aroma volatiles. Leucine addition effected further growth and higher volatiles production. In the headspace, ethanol and ethyl acetate accounted for 92% of total volatiles over the synthetic medium and 89% when leucine was added. Aroma perception (fruity and banana) correlated closely with liquid and headspace total volatiles.     

Chemical Composition of Lipids from Peat-Forming Leafy Mosses of Eutrophic Swamps of Western Siberia and Altai

The molecular composition of lipids in three samples of leafy mosses (Aulacomnium palustre, Warnstorfia fluitans, and Calliergon giganteum) has been determined. The revealed acyclic compounds included normal and isoprenoid alkanes, isoprenoid alkenes, normal and isoprenoid ketones, carboxylic acids and their esters, alcohols, and aldehydes. Among cyclic compounds, bi-, tri- and tetracyclic polycycloaromatic hydrocarbons (PAHs), bicyclic and pentacyclic terpenoids, steroids and tocopherols have been observed. The identified organic compounds consisted mainly of carbocyclic acids and n-alkanes with the prevalence of C₂₇ homologues. A. palustre is characterized by a reduced content of isoprenoid compounds, alcohols, and ketones, while the content of unsaturated acids, pentacyclic terpenoids, and aldehydes is rather heightened. A. palustre differs from W. fluitans and C. giganteum in the steroid composition and contains eremophylene, a sesquiterpenoid, which is absent in the mosses of the family Amblystegiaceae. Compared to C. giganteum, W. fluitans has a higher content of lycopadiene, carboxylic acids, n-alkanes, phyt-2-ene, aldehydes, esters, squalene, diploptene, α-tocopherol, and triphenyl phosphates.     

SPME‐GC/MS Analysis of Volatile Compounds Contained in the Insect Larvae of Tenebrio molitor and Leptinotarsa decemlineata before and after Using Insecticides

The larvae of two harmful insect species Tenebrio molitor and Leptinotarsa decemlineata were analyzed. The insects were sprayed with insecticides containing the active substances cyfluthrin and deltamethrin (T. molitor), and thiamethoxam and acetamiprid (L. decemlineata). The sprayed insect larvae were left for 24, 48 and 72 h. Samples were then prepared using SPME fiber to identify the volatile compounds contained in the larvae. The determinations were made by gas chromatography coupled with mass spectrometry (GC/MS). Chemical compounds were found in the analyzed samples: alkanes, aldehydes, ketones, esters, terpenes, fatty acids. In the samples prepared from T. molitor larvae, more than 20 % of aldehydes and 8–41 % of alkanes were determined. In the samples from L. decemlineata, fatty acids were 8–65 % depending on the length of time after applying the insecticide.     

Comprehensive volatile organic compounds profiling of Bacillus species with biocontrol properties by head space solid phase microextraction with gas chromatography-mass spectrometry

The eight Bacillus strains, used as biocontrol agents with proven antagonistic effect against plant pathogens, produced antifungal volatile organic compounds (VOCs). Bioassay in sealed dishes revealed that the VOCs from each Bacillus strain significantly inhibited the mycelial growth (56–82%) of Fusarium solani. The effective antifungal VOCs were extracted using headspace solid phase microextraction and further identified by gas chromatography-mass spectrometry technique. The detected volatile compounds could be chemically grouped into ketones, alcohols, aldehydes, pyrazines, acids, esters, pyridines and benzene compounds. The ketones and alcohols were predominant in the VOCs from eight Bacillus strains whereas the ketones, including 3-methyl-2-pentanone, 2-heptanone, 2-octanone, 2-decanone, 5-methyl-2-hexanone, 2-nonanone, 2-dodecanone, 2-undecanone, 5-methyl-2-heptanoneand2-pentanone, were the most common and principal components in all strains. Present results showed that the eight Bacillus strains are rich resources of bioactive volatiles, which may play an important role in the inhibition on F. solani. Studies are under the way to determine effects of those compounds against plant pathogens and to find the possible action mechanisms.     

A surface active protein involved in aerial hyphae formation in the filamentous fungus Schizophillum commune restores the capacity of a bald mutant of the filamentous bacterium Streptomyces coelicolor to erect aerial structures

The filamentous bacterium Streptomyces coelicolor undergoes a complex process of morphological differentiation involving the formation of a dense lawn of aerial hyphae that grow away from the colony surface into the air to form an aerial mycelium. Bald mutants of S. coelicolor, which are blocked in aerial mycelium formation, regain the capacity to erect aerial structures when exposed to a small hydrophobic protein called SapB, whose synthesis is temporally and spatially correlated with morphological differentiation. We now report that SapB is a surfactant that is capable of reducing the surface tension of water from 72 mJ m^?2 to 30 mJ m^?2 at a concentration of 50 μg ml^?1. We also report that SapB, like the surface-active peptide streptofactin produced by the species S. tendae, was capable of restoring the capacity of bald mutants of S. tendae to erect aerial structures. Strikingly, a member (SC3) of the hydrophobin family of fungal proteins involved in the erection of aerial hyphae in the filamentous fungus Schizophyllum commune was also capable of restoring the capacity of S. coelicolor and S. tendae bald mutants to erect aerial structures. SC3 is unrelated in structure to SapB and streptofactin but, like the streptomycetes proteins, the fungal protein is a surface active agent. Scanning electron microscopy revealed that aerial structures produced in response to both the bacterial or the fungal proteins were undifferentiated vegetative hyphae that had grown away from the colony surface but had not commenced the process of spore formation. We conclude that the production of SapB and streptofactin at the start of morphological differentiation contributes to the erection of aerial hyphae by decreasing the surface tension at the colony surface but that subsequent morphogenesis requires additional developmentally regulated events under the control of bald genes.     

Formation of volatile alcohols and esters from aldehydes in strawberries

The aldehydes acetaldehyde, propanal, 2-methylpropanal, butanal, 3-methylbutanal, pentanal and hexanal, were reduced to their corresponding alcohols by incubation with strawberry fruit. The alcohols formed were then converted to their acetate, propionate, n-butyrate, isovalerate and n-caproate esters during the incubation with strawberry fruit. Simultaneous reaction of isobutyric acid, n-valeric acid and isocaproic acid with aldehyde and strawberry fruit resulted in the formation of esters of these acids. In all seven alcohols and 54 esters were produced by means of incubation of aldehydes and volatile fatty acids with strawberry fruit.     

Screening of compounds stimulating spore formation and mycelial growth of pock-forming plasmid-carrying strains in Streptomyces azureus

Summary Sporulation-stimulating compounds were screened by using mutant PK100a of Streptomyces azureus ATCC 14921, in which spore formation was markedly inhibited by the pock-forming plasmid pSA1.1. On agar media, cysteine, bacitracin, glutathione and -NAD induced the formation of coloured spores or spore mass of strain PK100a. These compounds also stimulated the spore formation of the wild-type and its plasmid-cured (good spore-forming) strains and the growth of aerial mycelia of these three strains. This screening method appears to be an effective method for the screening of substances that stimulate spore formation and mycelial growth of streptomycetes or that overcome the inhibitory effect of pock-forming plasmids. Correspondence to: S. Ogata     

链霉菌的功能及其在农业上的应用

链霉菌是自然界中大量存在的一类微生物,具有多种多样的功能,其基内菌丝多核有间隔,气生菌丝上附着孢子链,从孢子萌发到孢子释放完成整个生命周期。链霉菌以菌丝体的形式定殖于多种植物体的根、茎、叶等部位而发挥功能,能分泌多种具有促进植物生长与生物防治功能的代谢物。对近几年链霉菌在提升植物营养吸收、促进植物生长、增强植物应对逆境能力、改善土壤结构、恢复污染水体等方面的研究进行了综述,并对今后链霉菌的研究方向和应用前景进行了展望。     

The Influence of n-Propanol on the Growth and Conidiation of Pestalotia rhododendri

Pestalotia rhododendri was exposed to vapours from 1 ml propanol solution in water and linear growth, formation of aerial hyphae and production of conidia were determined. A special Petri dish technique was used and maximum stimulation of conidial formation was induced by the vapours from a propanol concentration of 3–4 % (v/v) at 25°C. When propanol was added directly to the medium, a concentration of 1.2 × 10^?2M was optimal for growth and sporulation at 30°C. Sporulation stimulated by propanol was observed at temperatures from 20–32°C, with an optimum at 30°C. Certain observations indicated that an exposure to propanol for 24 hours was enough to induce a stimulated spore production. The stimulation was noticed on different media at 25°C, and was more pronounced at 30°C. One exception was observed. Propanol did not promote sporulation when the fungus was grown on maltagar at 30°C. Propanol 3 ° (v/v) in combination with the standard medium containing (NH₄)₂-tartrate as sole nitrogen source, inhibited the linear growth at 15–20°C, was inactive at 22.5° and 25°C, and stimulated growth at 27.5–31°C. The stimulatory effect was maximal at 30°C. Other media were tested at 25° and 30°C. At both temperatures stimulations of linear growth caused by propanol were observed with a medium containing KNO₃ as sole nitrogen source, and inhibitions with maltagar and another medium containing l -asparaginc as sole nitrogen source. The linear growth could be either inhibited or stimulated while the sporulation was stimulated.     

Profiles of the Essential Oils and Headspace Analysis of Volatiles from Mandragora autumnalis Growing Wild in Tunisia

Mandragora autumnalis Bertol . (Solanaceae family), synonym of M. officinalis Mill ., occurs in North Africa and grows natively in Northern and Central Tunisia, in humid to sub‐arid climates. The ripe fruits of mandrake are odiferous with a particular, indescribable, specific odor, shared, to a lesser extent, by the leaves and roots. We carried out an investigation of the essential oils (EOs) and of the aromatic volatiles emitted by fresh leaves, roots and ripe fruits of M. autumnalis growing wild in Central Tunisia. The EOs were obtained from freshly collected plant material by hydrodistillation, while the volatile emissions from the powdered M. autumnalis tissues were sampled by headspace solid phase microextraction (HS‐SPME); both types of samples were analyzed by gas chromatography‐mass spectrometry (GC/MS). Fifty‐one compounds representing 96.2–98.6 % of the total oil compositions were identified in the three tissues and belonged to different chemical classes specifically in 16 esters, 12 alcohols, 12 hydrocarbons, 6 ketones, 3 aldehydes and 3 acids. The main constituents were pentadecanoic acid (34.2 %) and hexadecanol (26.3 %). A total of 78 volatile compounds emanating from M. autumnalis tissues, representing 94.1–96.4 % of the total volatile compositions, were identified: 22 esters, 11 alcohols, 9 aldehydes, 14 ketones, 7 nitrogen, 10 hydrocarbons, 2 lactones, 1 sulfur and 2 ethers. Ethyl hexanoate (12.3 %) and 1,3‐butanediol (12.3 %) were at the highest relative percentages. This study characterizes and distinguishes M. autumnalis from Tunisia and attributes the compounds responsible for the intoxicating and particular odor of fruits. Chemosystematic of Mandragora autumnalis based on the identification of essential oils and headspace volatiles of each of its organ can be used to characterize this species according to its geographic distribution.     

Behavioral and electroantennogram analysis of olfactory stimulation inlozenge: ADrosophila mutant lacking antennal basiconic sensilla (Diptera: Drosophilidae)

Two alleles of the mutant lozengeof Drosophila melanogaster, lzand lz³,lack basiconic sensilla on the antennal funiculus. To elucidate the role of these sensilla for the perception of food odors, we studied the locomotor behavior and the electroantennogram (EAG) activity of lozenge flies in response to olfactory stimuli. The significance of basiconic sensilla on the maxillary palps was assessed by testing the locomotion of flies surgically deprived of their palps. The behavioral data suggest that antennal and maxillary basiconic sensilla may be important receptors for short chain alcohols and organic acids but less crucial receptors for acetates, aldehydes, and ketones. In agreement with this interpretation, EAG responses to alcohols (but not to esters) were found to be markedly lower in lozengethan in the wild type.     

Degradation of long chain n-alkanes by mucorales

Summary Extracellular oxidation products isolated from the substrates ofMortierella isabellina (CBS 224. 35) grown on n-dodecane and n-tridecane were primary and secondary isomeric alcohols, isomeric ketones, aldehydes and isomeric esters with the same numbers of carbon atoms presented in the used n-alkanes as detected by combined glass capillary gas chromatography — mass spectrometry. All esters were identified which theoretically could originate in the isomeric ketones by a reaction mechanism resembling a Baeyer-Villinger-type oxidation.     

内生真菌司氏角担子菌B6对尖孢镰刀菌西瓜专化型菌株的拮抗作用

近年来,尽管西瓜产业不断发展壮大,但轮作土壤种植西瓜易产生枯萎病害导致世界范围内的西瓜严重减产。通过对峙培养实验和抑菌实验探讨了重阳木内生真菌司氏角担子菌(Ceratobasidum stevensii)B6菌株对西瓜枯萎病病原菌尖孢镰刀菌西瓜专化型(Fusarium oxysporum f. sp.Niveum,FON)的拮抗作用,并初步分析了其作用机制。平板拮抗试验的结果表明,内生真菌B6生长过程中不是通过产生抑菌带来抑制FON菌丝,而是利用自身的生长优势将FON完全覆盖。显微观察B6与FON菌丝的接触部位,发现FON菌丝外侧附着B6顶端菌丝形成的胞样结构,表明FON菌丝生长仅受到B6菌丝的抑制。抑菌试验结果显示,B6产生的挥发性物质可以抑制FON的生长和产孢,并使其菌丝分枝明显减少;B6的发酵液对FON的生长和产孢没有抑制作用。因此,推测B6主要通过释放某些挥发性物质产生拮抗作用而抑制FON的生长。     

Enantiomer Distribution of Major Chiral Volatile Organic Compounds in Selected Types of Herbal Honeys

In this article, volatile organic compounds in 14 honey samples (rosemary, eucalyptus, orange, thyme, sage, and lavender) were identified. Volatile organic compounds were extracted using a solid phase microextraction method followed by gas chromatography connected with mass spectrometry analysis. The studied honey samples were compared based on their volatile organic compounds composition. In total, more than 180 compounds were detected in the studied samples. The detected compounds belong to various chemical classes such as terpenes, alcohols, acids, aldehydes, ketones, esters, norisoprenoids, benzene and furane derivatives, and organic compounds containing sulfur and nitrogen heteroatom. Ten chiral compounds (linalool, trans‐linalool oxide, cis‐linalool oxide, 4‐terpineol, α‐terpineol, hotrienol, and four stereoisomers of lilac aldehydes) were selected for further chiral separation. Chirality 26:670‐674, 2014. © 2014 Wiley Periodicals, Inc.     

Seed Dormancy in Red Rice : VII. Structure-Activity Studies of Germination Stimulants

Many chemically dissimilar substances break dormancy of seeds, but the relationship between chemical structure and physiological activity is unknown. In this study, the concentrations of organic acids, esters, aldehydes, alcohols, and inorganic weak acids required to elicit 50% germination of initially dormant, dehulled red rice seeds (Oryza sativa) were determined. The activity of most substances was very highly and inversely correlated to lipophilicity as measured by octanol/water partition coefficients; chemicals with the highest partition coefficients required the lowest concentrations to elicit the germination response. Relative efficacy was also dependent upon the functional group; generally, monocarboxylic acids were more effective than aldehydes, esters, hydroxyacids, and alcohols. Relative hydrophobicity plots supported a modulating role of the functional group. Dormancy-breaking activity of methyl formate, formic acid, nitrite, azide, and cyanide was higher than predicted based on lipophilicity and apparently was related to molecular size; compounds with smaller molecular widths were required at lower concentrations to achieve the 50% germination response.     

Lipophilic compounds in femoral secretions of males and females of the El Hierro giant lizard Gallotia simonyi (Lacertidae)

Many lizards use femoral gland secretions in reliable intraspecific communication. Based on mass spectra, obtained by GC–MS, we found 57 lipophilic compounds in femoral secretions of males and females of El Hierro giant lizards, Gallotia simonyi (fam. Lacertidae). Compounds included steroids (mainly cholesterol) and fatty acids ranging between n-C₁₆ and n-C₂₂ (mainly hexadecanoic and octadecanoic acids), followed by aldehydes, alcohols, ketones, squalene and waxy esters. There were important intersexual differences in the presence, abundance and number of compounds (more numerous in males). Males had higher proportions of the most odoriferous compounds (fatty acids and aldehydes), while females had higher proportions of more stable compounds (steroids, waxy alcohols, waxy esters and terpenoids). This suggests sexual differences in function of femoral secretions. In addition, some compounds could reflect the physiological state, allowing monitoring health of lizards from secretions samples, which is especially important given the critical conservation status of this lizard.     

Reactive oxygen species contribute to the release of volatile organic compounds from Chlamydomonas reinhardtii during programmed cell death

Acetic acid at pH 5.0 can induce programmed cell death (PCD) in Chlamydomonas reinhardtii cells, and abundant volatile organic compounds (VOCs) were released during the process. In this study, the caspase‐3‐like activity was determined during the PCD, and it was increased significantly after 1 h. During the PCD, the dynamic release of VOCs from the cells was analyzed, and the emissions of total VOCs were raised markedly and reached the highest level at 2 h. Among the seven types of VOCs, such as alkanes, alkenes, terpenoids, alcohols, aldehydes, ketones and esters, three oxygenated compounds (aldehydes, ketones and esters) showed the most significant increase. O₂^‐· and H₂O₂ were rapidly accumulated to high levels in the cells at the beginning of the PCD, but their content was reduced during the process. The activities of antioxidant enzymes were reduced gradually and even disappeared completely, demonstrating that the reduction of reactive oxygen species (ROS) may not be scavenged by the antioxidant enzyme system. ROS have an intense oxidation and scavenging ability to volatile compounds, and the oxidation results in the production of oxygenated compounds. Therefore, the abundant production of oxygenated compounds indicated that ROS may play an important role in the dynamic release of VOCs from C. reinhardtii cells during PCD.     

Expression of secondary alcohol dehydrogenase in methanogenic bacteria and purification of the F420-specific enzyme from Methanogenium thermophilum strain TCI

In four species of methanogens able to grow with secondary alcohols as hydrogen donors the expression and properties of secondary alcohol dehydrogenase (sec-ADH) were investigated. Cells grown with 2-propanol and CO₂ immediately started to oxidize secondary alcohols to ketones if transferred to new media. In the presence of H₂, such cells reduced ketones or aldehydes to alcohols. In the absence of H₂, aldehydes were dismutated (without growth) to primary alcohols and fatty acids. None of these reactions was catalyzed by cells grown with only H₂ and CO₂ at non-limiting concentration. This indicated an induction or derepression of sec-ADH by its substrate. Apparently, sec-ADH in all strains enabled not only the reduction of ketones or aldehydes, but also the dismutation of the latter. Sec-ADH was also expressed if strains were grown on H₂ and CO₂ in the presence of non-oxidizable, tertiary alcohols. Methanogenium thermophilum expressed sec-ADH even without added alcohol when H₂ became limiting. From this species, an F₄₂₀-specific sec-ADH was purified; the final gel filtration chromatography yielded a single protein peak that coincided with the activity. The enrichment was 12-fold, the activity recovery 26%. SDS polyacrylamide gel electrophoresis indicated that the enzyme was a homodimer with an apparent M _r of 79,000. At the pH optimum around 4.2, the specific activity for oxidation of 2-propanol (130 mM) and reduction of acetone (20 mM) was 176 and 110 mol/ min·mg, respectively (40°C). The apparent K _m for 2-propanol and acetone (with 15 M F₄₂₀) was 2.5 and 0.25 mM, respectively. Aldehydes also were reduced.Non-standard abbreviations ADH alcohol dehydrogenase - Bis-Tris bis(2-hydroxyethyl)imino-tris(hydroxymethyl)methane - F₄₂₀ N-(N-L-lactyl--L-glutamyl)-L-glutamic acid phosphodiester of 7,8-didemethyl-8-hydroxy-5-deazariboflavin-5-phosphate - Mb. Methanobacterium - Mg. Methanogenium - Ms. Methanospirillum - OD₅₇₈ optical density at 578 nm - SDS sodium dodecyl sulfate     

Characterization of alcohol dehydrogenase 1 and 3 from <Emphasis Type="Italic">Neurospora crassa</Emphasis> FGSC2489

Alcohol dehydrogenase (ADH) is a key enzyme in the production and utilization of alcohols. Some also catalyze the formation of carboxylate esters from alcohols and aldehydes. The ADH1 and ADH3 genes of Neurospora crassa FGSC2489 were cloned and expressed in recombinant Escherichia coli to investigate their alcohol dehydrogenation and carboxylate ester formation abilities. Homology analysis and sequence alignment of amino acid sequence indicated that ADH1 and ADH3 of N. crassa contained a zinc-binding consensus sequence and a NAD⁺-binding motif and showed 54–75% identity with fungi ADHs. N. crassa ADH1 was expressed in E. coli to give a specific activity of 289 ± 9 mU/mg using ethanol and NAD⁺ as substrate and cofactor, respectively. Corresponding experiments on the expression and activity of ADH3 gave 4 mU/mg of specific activity. N. crassa ADH1 preferred primary alcohols containing C3–C8 carbons to secondary alcohols such as 2-propanol and 2-butanol. N. crassa ADH1 possessed 5.3 mU/mg of specific carboxylate ester-forming activity accumulating 0.4 mM of ethyl acetate in 18 h. Substrate specificity of various linear alcohols and aldehydes indicated that short chain-length alcohols and aldehydes were good substrates for carboxylate ester production. N. crassa ADH1 was a primary alcohol dehydrogenase using cofactor NAD⁺ preferably and possessed carboxylate ester-forming activity with short chain alcohols and aldehydes.     

yatay椰子果实和果汁芳香成分分析

yatay椰子〔Butia yatay(M art.)Becc.〕原产于阿根廷、乌拉圭、巴拉圭及巴西南部,树干高3~6 m,直径约40 cm,羽状叶,叶柄两侧有齿状刺,雌雄同株,-7℃下能生存[1,2],属耐寒性椰子。果实黄色,秋天成熟,直径4~5 cm,能散发出强烈的香气;果肉酸甜可口,与柑橘和橙子味道相近。在巴西,yatay椰子除作为水果食用外,还可经发酵制成具有椰子香气的酒类饮料。除Rodenste in[3]曾经报道过yatay椰子果实的核与果肉的物化特性外,几乎没有关于yatay椰子的相关研究报道。为此,作者利用顶空吸附萃取-气相色谱-质谱〔HSSE(Head space sorptive extraction)-…