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1.
Ensifer sp. strain AS08 and Pseudomonas sp. strain AS90 degrading short ethoxy (EO) chain-nonylphenol (NP) [NPEOav2.0 containing NP mono- ∼ tetraethoxylates (NP1EO ∼ NP4EO); average 2.0 EO units] were isolated by enrichment cultures. Both strains grew on NP but not on octyl- and nonylphenol polyethoxylates (NPEOs) (average 10 EO units). Growth and degradation of NPEOav2.0 was increased with increased concentrations of yeast extract (0.02–0.5%) in a culture medium. Culture supernatants of both strains grown on NPEOav2.0 were analyzed by high-performance liquid chromatography, showing degradation of NP4EO–NP1EO. The metabolites from nonylphenol diethoxylate (NP2EO) by resting cells of both strains were identified by gas chromatography–mass spectrometry as nonylphenoxyethoxyacetic acid, NP1EO, nonylphenoxyacetic acid (NP1EC), and NP, while those from NP1EO were identified as NP1EC and NP. Cell-free extracts from strain AS08 grown on NPEOav2.0 dehydrogenated NPEOs, NPEOav2.0, NP2EO, NP1EO, and PEG 400, but the extracts were inactive toward di- ∼ tetraethylene glycol. Aldehydes were formed in the reaction mixture of each substrate with cell-free extracts. From these results, the aerobic metabolic pathway for short EO chain-NP is proposed: A terminal alcohol group of the EO chain is oxidized to a carboxylic acid via an aldehyde, and then one EO unit is removed. This process is repeated until NP is produced.English edition: The paper was edited by a native speaker through KN international () 相似文献
2.
Phytochemical composition of Hypericum genus has been investigated for many years. In the recent past, studies on the essential oils (EO) of this genus have been
progressing and many of them have reported interesting biological activities. Variations in the EO composition of Hypericum species influenced by seasonal variation, geographic distribution, phenological cycle and type of the organ in which EO are
produced and/or accumulated have also been reported. Although many reviews attributed to the characterization as well as biological
activities of H. perforatum crude extracts have been published, no review has been published on the EO composition and biological activities of Hypericum species until recently (Crockett in Nat Prod Commun 5(9):1493–1506, 2010; Bertoli et al. in Global Sci Books 5:29–47, 2011). In this article, we summarize and update information regarding the composition and biological activities of Hypericum species EO. Based on experimental work carried out in our laboratory we also mention possible biotechnology approaches envisaging
EO improvement of some species of the genus. 相似文献
3.
Arbuscular mycorrhiza alter the concentration of essential oils in oregano (Origanum sp., Lamiaceae)
The effect of root colonization by Glomus mosseae on the qualitative and quantitative pattern of essential oils (EO) was determined in three oregano genotypes (Origanum sp.). To exclude a simple P-mediated effect through mycorrhization the effect of P application to plants on the EO accumulation was also tested. In two genotypes the leaf biomass was increased through mycorrhization. Root colonization by the arbuscular mycorrhizal fungus (AMF) did not have any significant effect on the EO composition in oregano; however, in two genotypes the EO concentration significantly increased. As EO levels in P-treated plants were not enhanced, we conclude that the EO increase observed in mycorrhizal oregano plants is not due to an improved P status in mycorrhizal plants, but depends directly on the AMF–oregano plant association. 相似文献
4.
A sub-wavelength electro-optic switch based on plasmonic T-shaped waveguide has been proposed and numerically investigated.
The finite-difference time-domain simulation results reveal that the switch based on T-shaped waveguide with two U-shaped
grooves can realize the function of switching single wavelength from one port to the other by an external voltage. The U-shaped
structure is composed of two teeth filled with highly nonlinear organic EO material and one groove filled with 6H-SiC connecting
the two teeth. The switch wavelength can be chosen by adjusting both lengths of the left and right teeth, and the switch voltage
is 3.35 V for the wavelength of λ = 730 nm with the insertion loss around −2.6 dB and the extinction ratio around −20 dB at port 2. 相似文献
5.
Militello M Settanni L Aleo A Mammina C Moschetti G Giammanco GM Blàzquez MA Carrubba A 《Current microbiology》2011,62(4):1274-1281
This study was undertaken to characterize the essential oil (EO) of Artemisia arborescens growing wild in Sicily. EO, extracted by steam distillation, was examined for its chemical composition and for its capability
to inhibit some food-borne pathogen bacteria. A total of 43 compounds (13 monoterpene hydrocarbons, 14 oxygenated monoterpenes,
10 sesquiterpene hydrocarbons, three oxygenated sesquiterpenes and less amount of other three compounds), which account 93.73%
of the total oil, were identified by gas chromatography and gas chromatography–mass spectrometry. Oxygenated monoterpenes
(57.32%) constituted the main fraction, with β-thujone as the main compound (45.04%), followed by the sesquiterpene hydrocarbon
chamazulene (22.71%). Undiluted EO showed a large inhibition spectrum against strains of Listeria monocytogenes (34 out of 44), whilst it was ineffective against enterobacteria and salmonellas. The minimum inhibition concentration (MIC)
was evaluated for the two most sensitive strains (L. monocytogenes 186 and 7BO) at two cellular concentrations (106 and 107 CFU ml−1). The lowest MIC (0.625 μl ml−1, dilution of oil with acetone) was found for strain L. monocytogenes 186 at 106 CFU ml−1. 相似文献
6.
Martín Núñez Aleida J. Sandoval Alejandro J. Müller Guy Della Valle Denis Lourdin 《Food biophysics》2009,4(4):291-303
Gelatinization in excess of water and melting transition for different moisture contents of a ready-to-eat cereal formulation
(RTE blend) and its major components, (i.e., oat flour, rice flour, and an oat–rice flour blend) were studied by differential
scanning calorimetry (DSC) and rapid visco-analyzer (RVA). The highest swelling power was exhibited by the rice flour and
the lowest by the RTE blend. Two endothermic peaks under excess of water were exhibited by all materials, at 53–75 °C and
80–102 °C, and they were associated to gelatinization and cereal protein denaturation, respectively. A third peak appearing
in all materials except in rice flour, at higher temperatures (102–116 °C), was attributed to the melting of the amylose–lipid
complexes. The effect of water in the melting of the flours and blends was well described by the Flory–Huggins equation and
its parameters agreed well with those reported in the literature for starchy products. A theoretical value of the polymer–diluent
(starch–water) interaction factor for starch of 0.36 was calculated from a combined model of Hildebrand empirical approach
to solubility and the Flory–Huggins theory, and reasonably compared with the interaction parameter (χ) obtained for the materials considered in this work. State diagrams for the oat–rice flour blend and for the RTE blend going
through an extrusion process were finally obtained. 相似文献
7.
Arrival time on breeding or non-breeding areas is of interest in many ecological studies exploring fitness consequences of
migratory schedules. However, in most field studies, it is difficult to precisely assess arrival time of individuals. Here,
we use carbon isotope turnover in avian blood as a technique to estimate arrival time for birds switching from one habitat
or environment to another. Stable carbon isotope ratios (δ13C) in blood assimilate to a new equilibrium following a diet switch according to an exponential decay function. This relationship
can be used to determine the time a diet switch occurred if δ13C of both the old and new diet are known. We used published data of captive birds to validate that this approach provides
reliable estimates of the time since a diet switch within 1–3 weeks after the diet switch. We then explored the utility of
this technique for King Eiders (Somateria spectabilis) arriving on terrestrial breeding grounds after wintering and migration at sea. We estimated arrival time on breeding grounds
in northern Alaska (95% CI) from red blood cell δ13C turnover to be 4–9 June. This estimate overlapped with arrival time of birds from the same study site tracked with satellite
transmitters (5–12 June). Therefore, we conclude that this method provides a simple yet reliable way to assess arrival time
of birds moving between isotopically distinct environments. 相似文献
8.
We use a modeling approach to examine ideas derived from physiological network analyses, pertaining to the switch of a motor
control network between two opposite control modes. We studied the femur–tibia joint control system of the insect leg, and
its switch between resistance reflex in posture control and “active reaction” in walking, both elicited by the same sensory
input. The femur–tibia network was modeled by fitting the responses of model neurons to those obtained in animals. The strengths
of 16 interneuronal pathways that integrate sensory input were then assigned three different values and varied independently,
generating a database of more than 43 million network variants. We demonstrate that the same neural network can produce the
two different behaviors, depending on the combinatorial code of interneuronal pathways. That is, a switch between behaviors,
such as standing to walking, can be brought about by altering the strengths of selected sensory integration pathways.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
Nascimento AM Brandão MG Oliveira GB Fortes IC Chartone-Souza E 《Antonie van Leeuwenhoek》2007,92(1):95-100
The activity of Eremanthus erythropappus oil (EO) and some of its compounds and their potential synergistic interaction with ampicillin against different strains
of Staphylococcus aureus were investigated. Determination of chemical composition of EO by gas chromatography-mass spectrometry (GC/MS) and bioguided
chemical fractionation led to the identification of β-bisabolene as the main active compound. A synergistic bactericidal activity
of EO or β-bisabolene with ampicillin against Staphylococcus aureus was observed in a time-kill assay. EO and β- bisabolene have the potential to restore the effectiveness of ampicillin against
resistant S. aureus. 相似文献
10.
The abundance, food and feeding biology of Clarias albopunctatus was studied over a period of 17 months in the lower River
Anambra, Nigeria. The catfish was more abundant in late dry season (January–March) and early rainy season (April–June) than
in other periods of the year in the small-sized Akwu pond than in other habitats. Feeding intensity was higher at night and
at dawn (20.00–05.00 h) than during the day (08.00–17.00 h) in the 151–200 mm TL size class and during the rainy season (April–September).
There was no sex-dependent variation in feeding intensity. Insects were the predominant food, followed by crustaceans. Of
primary importance were Chironomidae (mainly Chironomus spp. and Tanypus sp.), Odonata nymphs, Dytiscus sp., mosquito larvae
and pupae, Gyrinus sp., Daphnia sp., Ostracoda and Tilapia fry. Qualitative food composition and food richness were size,
but not sex – or season-dependent. Diet breadth increased with catfish size and during the rainy season. The feeding behaviour
of the catfish include foraging, shovelling and surface feeding. Abundant food and ability to switch to more available items
enable C. albopunctatus to maintain its abundance in the River Anambra.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
Pottayil G. Sasikumar Maria Kempe 《International journal of peptide research and therapeutics》2007,13(1-2):129-141
Paramagnetic versions of the CLEAR supports were prepared by entrapment of magnetite particles during suspension polymerization
of allylamine, trimethylolpropane ethoxylate (14/3 EO/OH) triacrylate, and trimethylolpropane trimethacrylate. Swelling studies
in a broad range of solvents showed comparable swelling of magnetic beads and regular CLEAR beads. The application of the
magnetic beads as the support in solid-phase synthesis of peptides (Leu-enkephalinamide, substance P, acyl carrier protein
(65–74) amide, and amyloid β-protein (34–42) amide) and small organic affinity ligands based on the s-triazine scaffold was
demonstrated. Adequate stability of the beads and retention of their magnetic properties were observed throughout the synthesis
steps.
Abbreviations used for amino acids follow the IUPAC-IUB Commission of Biochemical Nomenclature (Jones, J. Pept. Sci., 12 (2006) 1). All amino acids used were of the L-configuration unless otherwise stated. All solvent ratios are volume/volume.
A preliminary report of portions of this work was presented at the 19th American Peptide Symposium in San Diego, CA, 2005
(Sasikumar and Kempe, 2006).
Dedicated to the memory of Bruce Merrifield (July 15, 1921–May 14, 2006). 相似文献
12.
The 37/67-kDa human laminin receptor (LamR) is a cell surface protein that interacts with molecules located in the extra-cellular
matrix. In particular, interactions between LamR and laminins play a major role in mediating changes in the cellular environment
that affect cell adhesion, neurite outgrowth, tumor growth and metastasis. The exact interaction mode of laminin-1 and LamR
is not fully understood. Laminin-1 is thought to bind to LamR through interaction with the so-called peptide G (residues 161–180)
and the C-terminal helix (residues 205–229). Here we performed 100-ns atomistic force field-based molecular dynamics simulations
to explore the structure and dynamics of LamR related to laminin-1 interactions. Our main finding is that loop 188–197 in
the C-terminal region is highly flexible. It undergoes a major change resulting in a conformational switch that partially
solvent exposes the R180 residue in the final part of the G peptide. So, R180 could contribute to laminin-1 binding. Projection
of the simulations along the first two principal components also confirms the importance of this conformational switch in
the LamR. This may be a basic prerequisite to clarify the key structural determinants of the interaction of LamR with laminin-1. 相似文献
13.
This study examined the effects of season-long exposure of Chinese pine (Pinus tabulaeformis) to elevated carbon dioxide (CO2) and/or ozone (O3) on indole-3-acetic acid (IAA) content, activities of IAA oxidase (IAAO) and peroxidase (POD) in needles. Trees grown in
open-top chambers (OTC) were exposed to control (ambient O3, 55 nmol mol−1 + ambient CO2, 350 μmol mol−1, CK), elevated CO2 (ambient O3 + high CO2, 700 μmol mol−1, EC) and elevated O3 (high O3, 80 ± 8 nmol mol−1 + ambient CO2, EO) OTCs from 1 June to 30 September. Plants grown in elevated CO2 OTC had a growth increase of axial shoot and needle length, compared to control, by 20% and 10% respectively, while the growth
in elevated O3 OTC was 43% and 7% less respectively, than control. An increase in IAA content and POD activity and decrease in IAAO activity
were observed in trees exposed to elevated CO2 concentration compared with control. Elevated O3 decreased IAA content and had no significant effect on IAAO activity, but significantly increased POD activity. When trees
pre-exposed to elevated CO2 were transferred to elevated O3 (EC–EO) or trees pre-exposed to elevated O3 were transferred to elevated CO2 (EO–EC), IAA content was lower while IAAO activity was higher than that transferred to CK (EC–CK or EO–CK), the change in
IAA content was also related to IAAO activity. The results indicated that IAAO and POD activities in Chinese pine needles
may be affected by the changes in the atmospheric environment, resulting in the change of IAA metabolism which in turn may
cause changes in Chinese pine’s growth.
An erratum to this article can be found at 相似文献
14.
All-optical plasmonic switches based on a novel coupled nano-disk cavity configuration containing nonlinear material are proposed
and numerically investigated. The finite difference time domain simulation results reveal that the single-disk plasmonic structure
can operate as an “on–off” switch with the presence/absence of pumping light. We also demonstrate that the proposed T-shaped
plasmonic structure with two disk cavities can switch signal light from one port to another under an optical pumping light,
functioning as a bidirectional switch. The proposed nano-disk cavity plasmonic switches have many advantages such as compact
size, requirement of low pumping light intensity, and ultra-fast switching time at a femto-second scale, which are promising
for future integrated plasmonic devices for applications such as communications, signal processing, and sensing. 相似文献
15.
The marine phage ϕHSIC has been previously reported to enter into a pseudolysogenic-like interaction with its host Listonella pelagia. This phage–host system displays behaviors that are characteristic of both pseudolysogeny and lysogeny including a high rate of spontaneous induction and chromosomal integration of the prophage. To determine what parameters may influence the transition from lysogenic to lytic existence in the ϕHSIC/L. pelagia phage–host system, cultures of this organism were incubated under different environmental conditions, while host cell growth and bacteriophage production were monitored. The environmental parameters tested included salinity, temperature, a rapid temperature shift, and degree of culture aeration. The highest titers of phage were produced by HSIC-1a cells grown in high-salinity nutrient artificial seawater media (67 ppt with a natural salinity equivalent of 57 ppt) or those cultured in highly aerated nutrient artificial seawater media (cultures shaken at 300 rpm). Conversely, the lowest titers of phage were produced under low salinity or rate of aeration. In general, conditions that stimulated growth resulted in greater lytic phage production, whereas slow growth favored lysogeny. These results indicate that elevated salinity and aeration influenced the switch from lysogenic to lytic existence for the phage ϕHSIC. These results may have implications for environmental controls of the lysogenic switch in natural populations of marine bacteria. 相似文献
16.
Lin Ke Hong Liu Sok Yee Yew Peh Kangnuo Connor Eunice Leong Surani Bin Dolmanan Jing Hua Teng 《Plasmonics (Norwell, Mass.)》2012,7(1):19-24
Confinement of exciton–polaritons using ridge–trench structures filled with fluorescent dye materials was investigated on
the basis of geometrical analysis as well as plasmonic behavior analysis. It was found that the photoluminescence intensity
of the dye increased significantly in the trench than on the ridge due to geometry confinement. However, with silver layer
deposited between the ridge–trench structure on Si substrate and the fluorescence dye, apparent photoluminescence peaks due
to surface plasmon resonance centered at 360 nm (3.45 eV) were generated while the photoluminescence peaks of the dye materials
centered at 580 nm (2.14 eV) quenched in the trench. Competition of spontaneous emission coupled into external electromagnetic
modes and plasmon modes is the cause for the quench in photoluminescence. Our results show a direct energy transfer from low-energy
photoluminescence to higher energy photoluminesence in dye materials due to plasmonic resonance effects. 相似文献
17.
Mendes GC Brandão TR Silva CL 《Journal of industrial microbiology & biotechnology》2011,38(9):1535-1543
Ethylene oxide is currently a dominant agent in medical device sterilization. This work intends to study the main effects
and interactions of temperature, ethylene oxide concentration, and relative humidity on commercial spore strips of Bacillus subtilis, var. niger (ATCC 9372) inactivation, the most common microorganism used in controlling the efficacy of the process. Experiments were
carried out using a full factorial experimental design at two levels (23 factorial design). Limit target exposure conditions for ethylene oxide concentration, temperature, and relative humidity
were 250–1,000 mg EO/l, 40–60°C, and 50–90%, respectively. Adopting a different approach from the first-order kinetics, a
Gompertz model was successfully applied in data fitting of the inactivation curves. Bacillus subtilis kinetic behavior presented a sigmoidal inactivation with an initial shoulder (λ), followed by a maximum inactivation rate
(kmax), these being model parameters. It was concluded that temperature and ethylene oxide concentration were the most significant
factors and consequently, additional experiments were carried out aiming at describing the parameters' dependence on these
process factors. Mathematical relations describing such dependences were successfully developed and included in the Gompertz
kinetic model. The predictive ability of this integrated model was assessed, and its adequacy in predicting B. subtilis inactivation was proven. 相似文献
18.
The structures of ZnO graphene–like nanosheets (ZnOGLNS), i.e., ZnO aromatic–like (AL–ZnONS), naphthalene–like (NLL–ZnONS),
pyrene–like (PRL–ZnONS), coronene–like (CNL–ZnONS) and circumcoronene–like (CCL–ZnONS) and their oxygen adsorptions were obtained
using the B3LYP/LanL2DZ method. Adsorption energies of O2 on AL–ZnONS, NLL–ZnONS, PRL–ZnONS, CNL–ZnONS and CCL–ZnONS are reported. The bond strengths of the most inner Zn–O bonds
of ZnOGLNSs are in order: CCL–ZnONS > CNL–ZnONS > PRL–ZnONS. It was found that chemisorptions of O2 occur on the hydride atoms of zinc–hydride in the ZnOGLNSs. Physisorptions of O2 only occurring over the plane of ZnOGLNS were found. All the ZnOGLNSs are oxygen sensitive materials and would be developed
to be oxygen sensor based on electrical conductivity. 相似文献
19.
Sunflower seeds and its products are widely consumed as fodder and vegetable oil in India. The mycobiota is known to produce
hazardous effects to the consumer by producing toxins. Hence the mycobiota starting from seed stage to kernel, Oiled Cake
(OC), De-Oiled Cake (DOC), Solvent Extracted Oil (SEO), Expeller Oil (EO) and Refined Oil (RO) were studied using Czapek-Dox
agar. Altogether 24 non-xerophilic species belonging to 12 genera were isolated. The fungus Aspergillus flavus was found to be predominant in seeds with 22.3 % contribution to the total. In the kernel, Mucor racemosus was dominant and contributed 31.6 %. In OC and DOC, Rhizopus stolonifer was dominant with 31.1 % and 45.9 % respectively. In EO and SEO, Aspergillus flavus and A. japonicus were dominant with 21 % and 32.4 % respectively. It was found that there was no fungal growth in RO. The study was conducted
between the periods 2000–2001. 相似文献
20.
Iron and citrate are essential for the metabolism of most organisms, and regulation of iron and citrate biology at both the
cellular and systemic levels is critical for normal physiology and survival. Mitochondrial and cytosolic aconitases catalyze
the interconversion of citrate and isocitrate, and aconitase activities are affected by iron levels, oxidative stress and
by the status of the Fe–S cluster biogenesis apparatus. Assembly and disassembly of Fe–S clusters is a key process not only
in regulating the enzymatic activity of mitochondrial aconitase in the citric acid cycle, but also in controlling the iron
sensing and RNA binding activities of cytosolic aconitase (also known as iron regulatory protein IRP1). This review discusses
the central role of aconitases in intermediary metabolism and explores how iron homeostasis and Fe–S cluster biogenesis regulate
the Fe–S cluster switch and modulate intracellular citrate flux. 相似文献