共查询到20条相似文献,搜索用时 359 毫秒
1.
Angela Dibenedetto Rosa Lo Noce Carlo Pastore Michele Aresta Carlo Fragale 《Environmental Chemistry Letters》2006,3(4):145-148
A new biotechnological synthetic approach to 4-hydroxybenzoic acid is reported. Thauera aromatica cells produce the phenylphosphate carboxylase enzyme that selectively carboxylates phenylphosphate in the para position, without any formation of the ortho isomer. Here we show that the enzyme also works in supercritical carbon dioxide, opening a new technological solution to the recovery of the products that is a key problem when aqueous media are used. The enzyme shows an activity comparable with that shown under CO2 pressure in aqueous media and does not require the presence of NaHCO3. 相似文献
2.
Olle Anderbrant Donald S. Matteson C. Rikard Unelius Philip S. Pharazyn Ellen M. Santangelo Fredrik Schlyter Göran Birgersson 《Chemoecology》2010,20(3):179-187
Stereoisomers of 4-methyl-3-heptanol (MH) are pheromone components of several Scolytus bark beetles. The elm bark beetle Scolytus laevis (Coleoptera: Scolytidae) has in previous studies been caught in traps baited with commercial MH containing all four stereoisomers,
but the lure has been considered a weak attractant. In this study, we addressed the question whether stereospecific responses
by S. laevis to stereoisomers of MH might contribute to its niche separation from other sympatric Scolytus species. Using GC–MS, we analyzed extracts of hindguts and abdomens from male and female S. laevis and the sympatric S. triarmatus. We also tested all four MH-stereoisomers individually and in combinations in the field to determine their role for S. laevis. All four stereoisomers were synthesized via a boronic ester method with 1,2-dicyclohexylethanediol as chiral director. In
addition, the (3S,4R)-stereoisomer of MH was prepared through enantioselective, lipase-mediated transesterification of a mixture of the four stereoisomers
of MH. Females of both species contained small amounts of syn-MH, and males contained trace amounts of anti-MH. The anti stereoisomer
(3R,4S)-MH was attractive to male and female S. laevis, whereas the syn stereoisomer (3S,4S)-MH acted as an inhibitor or deterrent and reduced the catch when added to the attractive isomer. The syn isomer is the main
aggregation pheromone component of the larger and sympatric S. scolytus and possibly also of S. triarmatus. The avoidance response of S. laevis to the (3S,4S)-stereoisomer may reduce interspecific competition for host trees. 相似文献
3.
Studies were made of some carotenoids extracted from Axinella verrucosa (O. schmidt) (Porifera: Demospongiae), a species which occurs in the Gulf of Naples. -carotene, renieratene, isorenieratene, and an unknown isomer of renieratene have been isolated. 相似文献
4.
The photolysis of the N methyl carbamate pesticide oxamyl (Z isomer) has been studied in aqueous solution. Continuous irradiation at mainly λ = 254 and λ > 290 nm has been performed to characterise the pesticide photochemical behaviour in water at pH = 6.0. Upon monochromatic irradiation, the phototransformation quantum yield was evaluated to be roughly constant, with a value of 0.54 ± 0.08. Upon polychromatic irradiation, a photochemical efficiency has been estimated to be 0.5 ± 0.1 by using phenol as a reference compound. Two main degradation products were identified: the isomer (E) of oxamyl and the nitrile derivative (N,N-dimethyl-2-nitrilo-acetamide). The photolysis of the oximino derivative, an hydrolysis product of oxamyl, was also studied. Upon irradiation at 254 nm, the quantum yield of phototransformation was found to be 0.28. A unique photoproduct was detected: it corresponds to the (E) isomer of the oximino derivative. For prolonged irradiations, a photostationary state was reached between the oximino and its (E) isomer. From kinetics data, the removal of oxamyl and of the oximino derivative during a UV disinfection step used in drinking water production was calculated to be 45 and 13%, respectively. 相似文献
5.
J. W. Farrington B. W. Tripp J. M. Teal G. Mille K. Tjessem A. C. Davis 《毒物与环境化学》2013,95(3-4):331-346
Investigations into the fate of petroleum compounds in the marine environment were carried out using experimental microcosms of two sizes and designs. Aromatic hydrocarbons or No. 2 fuel oil were spiked to the water of a 13 m3 continuous flow system and to a 2281 recycled flow system. The transport and alteration of this oil was traced in the sediment and benthic organisms (Glycera americana, Crepidula sp., and Nephtys incisa) of these microcosms. Measurable contamination was found in both sample types. The aromatic hydrocarbon distribution, including relative isomeric distribution (e.g., C2‐phenanthrenes) was found to be different in sediment and in organisms from that which was originally introduced to the experimental microcosm. Differences in isomer distribution between Glycera and Crepidula were also detected. Based on the experimental data: molecular weight and specific isomeric form, biochemical processes, solubility, and particle adsorption/desorption influence the fate of petroleum compounds in benthic ecosystems. 相似文献
6.
Variations in pigment contents of the diatom Phaeodactylum tricornutum during growth 总被引:1,自引:0,他引:1
Changes in the amounts of chlorophyll a, chlorophyll c, fucoxanthin, diadinoxanthin and -carotene were determined during Phaeodactylum tricornutum growth. The transition of the culture from the logarithmic to the stationary phase is accompanied by an increase in the carotenoids: chlorophyll a ratio, associated with variations in the percentage of individual carotenoids. While fucoxanthin content decreases with the age of the culture, diadinoxanthin content increases and -carotene remains almost constant. The furanoid isomer of diadinoxanthin, absent during logarithmic growth, appears increasingly during the nutrient-deficient period. Changes in the amounts of chlorophyll a, chlorophyll c and fucoxanthin are quite similar. 相似文献
7.
K. M. Nowak V. N. Kouloumbos A. Schäffer P. F.-X. Corvini 《Environmental Chemistry Letters》2008,6(1):53-58
We studied the accumulation of p353-nonylphenol residues in the biomass of grass grown in soil amended with sewage sludge
submitted to various conditioning/dewatering treatments. Incubation experiments were conducted growing Poa pratensis in sludge-amended soils and applying one 14C-labelled isomer of nonylphenol in the different systems. More metabolites than parent compounds were recovered in both roots
and leaves of the grass. The type of sludge conditioning and dewatering treatment had a slight effect on the bioaccumulation
of nonylphenol and its metabolites. When the grass was cultivated in soils amended with dewatered sludge without conditioning
pretreatment, an increased accumulation was observed in the roots, while the final biomass of the grass was lower. 相似文献
8.
The purpose of this study was to examine the sublethal and/or lethal effects produced by exposure of teleostean fish Solea senegalensis to γ isomer of lindane, γ-hexachlorocyclohexane (γ-HCH). S. senegalensis was exposed to 0.1, 1 or 10 mg L?1 of lindane for 96 h. Samples of different tissues (gills, liver and kidney) were extracted and processed for histopathological observations. The 72 h LC50 value of pesticide was found to be 0.16 ± 0.04 mg L?1 γ-HCH. Histological observations including aneurysms and hypertrophy of lamellar epithelia in gills, blood stagnation and vacuolization in liver and alterations in the hematopoietic tissue in kidney were observed. The results of the study show the sensitivity of juvenile of S. senegalensis to lindane and histology as a reliable tool to detect the sublethal effects of pollutants on the environment and aquatic biota. The toxicological implications arising from these results are the subject for further multi-concentration tests useful in establishing water quality criteria. 相似文献
9.
Growth, photosynthetic capacity and chlorophyll a content of the marine diatom Phaeodactylum tricornutum Bohlin were observed after exposure to the aromatic hydrocarbon 9–10 dihydroanthracene and its biodegradation products. Growth was inhibited after exposure to the aromatic hydrocarbon, whereas no inhibition occurred in the presence of the biodegradation products alone. The degradation products were found to enhance the chlorophyll a cellular content. Synergistic effects between dihydroanthracene and its biodegradation products increased the toxicity of this aromatic hydrocarbon. 相似文献
10.
Juan Camilo Marín Loaiza Carlos L. Céspedes Till Beuerle Claudine Theuring Thomas Hartmann 《Chemoecology》2007,17(2):109-115
Summary. The occurrence of pyrrolizidine alkaloids (PAs) in Pittocaulon (ex Senecio) praecox (Asteraceae) a species endemic to Mexico was established. The aboveground plant organs contain the 1,2-saturated monoester
7-angeloyl-dihydroxyheliotridane together with a small proportion of its 9-angeloyl isomer as major alkaloid. The monoesters
are accompanied by the macrocyclic otonecine derivative senkirkine. Roots contain only related macrocyclic PAs with senecionine,
senkirkine and platyphylline as major components; monoesters are absent. The broom-like succulent stems of P. praecox are infested by the scale insect Ceroplastes albolineatus conspicuously visible by its huge wax cover. All life-history stages, i.e. females, eggs, first instar nymphs (crawlers)
and the wax cover were found associated with PAs. The measured PA concentrations clearly indicate sequestration. The highest
PA concentrations (mg / g dry weight) reached are: mature females, 0.44; eggs, 0.58; crawlers, 0.37; wax cover, 0.08. The
host plant as well as in the infesting scale insect contain the PAs exclusively as free bases. As a phloem-feeder C. albolineatus must acquire the PAs with the ingested phloem sap. This appears plausible since in Senecio species PA are transmitted and circulated through the phloem path. It is suggested that PAs may protect particularly the
crawlers as the most endangered stage in the life-cycle of the scale insect. 相似文献
11.
Shinsuke Tanabe Narayanan Kannan Tadaaki Wakimoto Ryo Tatsukawa Taku Okamoto Yoshito Masuda 《毒物与环境化学》2013,95(4):215-231
In the light of new discoveries on the extremely toxic non‐ortho coplanar 3,3’,4,4'‐tetra‐ (T4CB), 3,3’,4,4’,5‐penta‐(P5CB) and 3,3'4,4’,5,5'‐hexachlorobiphenyl (H6CB) and their mono‐ and di‐ortho analogs, tissue samples of a Yusho poisoning victim and Yusho causal oils were subjected to a thorough congener/isomer‐specific investigation for polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo‐p‐dioxins (PCDDs). Among the many PCB congeners detected in Yusho oil, non‐ortho coplanar T4CB constituted 3.1%, P5CB‐0.17% and H6CB‐0.0072% in total PCBs. Their concentrations in liver and adipose tissue were 130–700 (T4CB), 54–720 (P5CB) and 50–380 (H6CB) pg/g on wet weight basis. The observed concentrations in adipose tissue were two to four fold higher than that detected in unexposed individuals. Among the PCDFs identified, toxic 2,3,7,8‐substituted isomers including 2,3,4,7,8‐P5CDF were the dominant ones. Tetra‐ through hepta‐CDDs were detected in the oil, whereas octa‐CDD was the dominant isomer in the patient. A comparison with KC‐400 revealed enrichment of coplanar PCBs in Yusho oil along with toxic PCDFs. Enrichment was highest for 3,3'4,4'5,5'‐H6CB followed by 3,3’,4,4'5‐P5CB. A comparative toxic evaluation of these chemical groups in Yusho patient's adipose tissue based on “2,3,7,8‐T4CDD Toxic Equivalent Analysis” revealed accountable toxic contribution from coplanar PCBs. This analysis also confirmed that 2,3,4,7,8‐P5CDF was the principal causative agent in Yusho poisoning. 相似文献
12.
Nataliya Voloshchuk Mona Knop Thomas Colby Erich Kombrink Lothar Hennig Diana Hofmann Dieter Sicker Andrej Gryganski Margot Schulz 《Chemoecology》2007,17(1):1-12
Summary. Doratomyces stemonitis (Hyphomycetales, Dematiaceae) is a saprotrophic fungus belonging to the mycobiota of the cereal rhizosphere. The fungus is
able to metabolize benzoxazolin-2-(3H)-one and a variety of its derivatives including higher plant detoxification products, microbial degradation products and
the chemically rather stable 2-amino-(3H)-phenoxazin-3-one. D. stemonitis can use all of these compounds as sole C-sources but their utilization, especially that of microbial degradation products
and 2-amino-(3H)-phenoxazin-3-one, seems to be highly energy consuming, resulting in slow mycelium growth and a change of colony morphology.
Benzoxazolin-2-(3H)-one derived compounds induce the synthesis of different isoforms of a glycosylated protein with sequence homologies to the
endo-1,3-β-glucanase Asp f2, an allergen from Aspergillus fumigatus and other Asp f2-like proteins e.g., from Verticillium dahliae or PRA1 antigen from Candida albicans. The induction of the protein is regarded as a stress response. 相似文献
13.
Peter Witzgall Jean-Pierre Chambon Marie Bengtsson C. Rikard Unelius Monica Appelgren Gyorgy Makranczy N. Muraleedharan Darwin W. Reed Klaus Hellrigl Hans-Ruedi Buser Eric Hallberg Gunnar Bergström Miklos Tóth Christer Löfstedt Jan Löfqvist 《Chemoecology》1996,7(1):13-23
Summary The geometric isomers (E,E)-, (E,Z)-, (Z,E)-, and (Z,Z)-8,10-dodecadien-1-yl acetate were identified as sex pheromone components or sex attractants in the tribes Eucosmini and Grapholitini of the tortricid subfamily Olethreutinae. Species belonging to the more ancestral Tortricinae were not attracted. Each one isomer was behaviourally active in males ofCydia andGrapholita (Grapholitini), either as main pheromone compound, attraction synergist or attraction inhibitor. Their reciprocal attractive/antagonistic activity in a number of species enables specific communication with these four compounds.Pammene, as well as otherGrapholita andCydia responded to the monoenic 8- or 10-dodecen-1-yl acetates. Of the tribes Olethreutini and Eucosmini,Hedya, Epiblema, Eucosma, andNotocelia trimaculana were also attracted to 8,10-dodecadien-1-yl acetates, but several otherNotocelia to 10,12-tetradecadien-1-yl acetates. The female sex pheromones ofC. fagiglandana, C. pyrivora, C. splendana, Epiblema foenella andNotocelia roborana were identified. (E,E)- and (E,Z)-8,10-dodecadien-1-yl acetate are producedvia a commonE9 desaturation pathway inC. splendana. CallingC. nigricana andC. fagiglandana females are attracted to wingfanning males. 相似文献
14.
The dechlorination of OCDD, OCDF and 1,2,3,4,7,8‐H6CDD is studies on an alumina support impregnated with activated carbon, copper chloride and potassium chloride. There is a high correlation between the isomer pattern found after dechlorination and molecular structure properties. We also found a substantial correlation between the isomer pattern and the Gibbs free energy of formation of the individual isomers. This suggests a thermodynamically controlled process. 相似文献
15.
Terpenes react quite rapidly with ambient ozone and lead via ozonides to highly oxidizing radicals and consecutive products forming aerosols. In the presence of SO2 sulphur containing compounds, mainly as sulphate, are formed. By means of gas chromatography/mass spectrometry and by comparison with known spectra the main products of the reaction of ß‐pinene (as a model compound) with ozone and sulphur dioxide could be identified. Reaction of terpenes with NO3‐radicals, which build up in the atmosphere at night‐time, leads to the formation of organic nitrates that form aerosols. The kinetics as well as the products of the reaction between NO3‐radicals and ß‐pinene have been studied by FTIR and MS. 相似文献
16.
Ecological and physiological studies focused on dietary preferences, lipid biochemistry and energetics within the three Antarctic
chaetognaths Eukrohnia hamata, E. bathypelagica and E. bathyantarctica from meso- and bathypelagic depths. Eukrohnia hamata and E. bathypelagica respired 0.15 μL O2 mg dry mass (DM)−1 h−1, which translates to an average metabolic loss of only <1.1% of body carbon per day. Lipid storage was not substantial in
E. bathypelagica (mean 11.5 ± 6.5% DM) and E. bathyantarctica (mean 15.4 ± 4.1% DM) during summer and winter, suggesting year-round feeding of these predators mainly on copepods. In E. bathypelagica, total fatty acids were dominated by the fatty acids 16:0, 20:5(n-3) and 22:6(n-3) and in E. bathyantarctica also by 18:1(n-9), a fatty acid usually found in storage lipids. Only the latter species was characterized by significant
amounts of wax esters, consisting largely of the common fatty alcohols 16:0, 20:1(n-9) and the unusual fatty alcohol isomer
22:1(n-9). 相似文献
17.
Summary. We have isolated a caffeoylcyclohexane-1-carboxylic acid derivative, 3-caffeoyl-muco-quinic acid (3-CmQA), as a contact oviposition stimulant for the zebra swallowtail butterfly, Eruytides marcellus (Papilionidae), from the foliage of its primary host plant, Asimina triloba (Annonaceae). This compound alone was as active in stimulating oviposition by females as were the parent ethanolic plant
extract and the host plant itself. Other tested isomers of 3-CmQA, including 5-caffeoylquinic acid (5-CQA or trans-chlorogenic acid), were inactive. We found, however, that experienced female butterflies responded strongly to host volatiles,
which enhanced landing rates and hence oviposition.? This is the first report of an oviposition stimulant for a swallowtail
butterfly of the tribe Graphiini. We found 3-CmQA to be the major caffeoylcyclohexane-1-carboxylic acid isomer in plants of the genus Asimina. These plants lack appreciable amounts of 5-CQA, which has been shown previously to be one of the oviposition stimulants
for certain Rutaceae- or Apiaceae-feeding swallowtails of the related tribe Papilionini.? Our findings, along with earlier
results from the tribes Troidini and Papilionini, suggest that responses by swallowtails to hydroxycinnamic acid derivatives
as oviposition cues date back at least to the ancestor of the subfamily Papilioninae.
Received 24 March 1998; accepted 27 May 1998. 相似文献
18.
The bacterium Serratia marsescens strain JAS16 was isolated from agricultural soil which had prior exposure to monocrotophos for three years. The strain JAS16 tolerated up to 1200 mg L–1 monocrotophos and degraded the insecticide (1000 mg L–1) at a degradation rate constant of 136 d?1 (DT50 = 3.7 d). In soil, the degradation rate constant was 105 d?1 (DT50 = 4.8 d). A schematic pathway is being proposed from the degraded products derived from gas chromatography--mass spectrometry (GC-MS). The phytotoxicity of degradation products to Vigna radiata, Vigna unguiculata, and Macrotyloma uniflorum and the genotoxicity to Allium cepa roots were found to be low. A cost-effective powder-based formulation was achieved with the isolate. The isolate remained viable during the storage and also multiplied with a higher colony forming units (CFU) load g–1 for over a period of seven weeks of storage. 相似文献
19.
Total lipid of Meganyctiphanes norvegica (M. Sars) contained 53% triacylglycerols and traces of wax esters, that of Thysanoessa raschi (M. Sars) contained 44% triacylglycerols and 10% wax esters and that of T. inermis (Krøyer) contained 28% triacylglycerols and 40% wax esters. The triacylglycerols of M. norvegica were relatively rich in 20:1 and 22:1 fatty acids and its traces of wax esters resembled those of calanoid copepods. The triacylglycerols of both Thysanoessa species were deficient in 20:1 and 22:1 fatty acids but were richer in 16:1(n-7) and 18:1 (n-7) acids than those of M. norvegica. The wax esters of T. raschi contained phytol as almost the only fatty alcohol and were rich in 16:0 and 18:1 (n-9) fatty acids. The wax esters of T. inermis contained mainly 16:0 and 14:0 fatty alcohols with lesser amounts of phytol and their dominant fatty acid was 18:1, especially the (n-9) isomer. The triacylglycerols of T. inermis had 18:4 (n-3) as the major polyunsaturated fatty acid. From these and other aspects of fatty acid and fatty alcohol analyses it is concluded that a major foodstuff of M. norvegica in Balsfjorden is wax ester-rich calanoid copepods. T. raschi and especially T. inermis are concluded to have much more preference for phytoplanktonic food. Results are discussed in terms of current knowledge of the lipid chemistry of krill in the northern and southern hemispheres. 相似文献
20.
Summary. The basic chemical structure of the sex
pheromone of the pine sawfly Microdiprion pallipes
(Fallén) has earlier been identified as the propionate
ester of (2S,3S,7R/S,11R/S)/(2R,3R,7R/S,11R/S)-3,7,11-
trimethyl-2-tridecanol. We now report the results from
further investigations on the male response to individual
stereoisomers and to blends of stereoisomers, both in electroantennographic
(EAG) recordings and in field trapping
experiments. We also present our attempts to determine the
stereochemistry of the compounds present in females of
M. pallipes. By comparing gas chromatograms and mass
spectra obtained from natural extracts with those from synthetic
compounds it was found that the females contain one
or more of the four (2S,3S,7R/S,11R/S)-3,7,11-trimethyl-2-
tridecanol isomers (SS++-1). The active pheromone component
is the corresponding propionate ester 2. In EAG
experiments, males responded most strongly to five propionate
ester samples, namely two four-isomer blends: SS++-2
and SR++-2, and three individual stereoisomers: SSSR-,
SRRR- and SRSR-2. In a series of field trapping experiments
it was found that males were attracted to the SR++-2
four-isomer blend and to the individual isomer SSSR-2.
Based on the EAG-recordings and field responses of males
and the stereoisomers found in the females, we suggest that
the propionate ester of (2S,3S,7S,11R)-3,7,11-trimethyl-2-
tridecanol (SSSR-2) is used as a main component of the sex
pheromone in M. pallipes. Apparently the males react to
other stereoisomers in addition to that or those produced by
the females. 相似文献