共查询到20条相似文献,搜索用时 31 毫秒
1.
Rodolfo Martínez-Mota Carolina Valdespino Juan Arturo Rivera Rebolledo Rupert Palme 《International journal of primatology》2008,29(5):1365-1373
Measuring fecal glucocorticoid metabolites is now a common practice to assess the stress response in primates. Nevertheless,
it is important to validate the utilized immunoassay for each primate species before the technique is applied to populations
in the wild. We determined the stress response of black howlers (Alouatta pigra) via 2 different group-specific enzyme immunoassays (EIAs). 11-oxoetiocholanolone EIAs are suited to assess the stress response
of black howlers via fecal glucocorticoid metabolites. Levels of fecal glucocorticoid metabolites increased after we applied
a stressor, i.e. anesthesia, reaching peak concentrations 24–96 h poststressor. Both basal and stress-induced fecal glucocorticoid
metabolite levels showed individual variations. The increase of fecal glucocorticoid metabolites after the stressor (paralleling
increases in serum) indicates that one can effectively measure adrenocortical activity in Alouatta pigra via these 2 enzyme immunoassays. However, it is important to consider individual variations in the excretion of fecal glucocorticoid
metabolites when planning field endocrinological research on Alouatta pigra. Fecal glucocorticoid metabolite excretion takes 1–3 d poststressor depending on the individual. Further, there is an important
individual variability in the concentrations of glucocorticoid metabolites, which might reflect differences in stress reactivity
or fecal glucocorticoid metabolite metabolism and excretion. 相似文献
2.
Takuya Uehara Hideshi Naka Shigeru Matsuyama Tetsu Ando Hiroshi Honda 《Applied Entomology and Zoology》2012,47(3):227-232
The sex pheromones of two species of hawk moth, Deilephila elpenor lewisii (Butler) and Theretra oldenlandiae oldenlandiae (Fabricius), were analyzed using gas chromatography–electroantennographic detection (GC–EAD) and GC–mass spectrometry (GC–MS). Two and three EAD-active components were found in D. elpenor lewisii and T. oldenlandiae oldenlandiae, respectively. GC–MS analyses using authentic compounds and extracts derivatized by dimethyl disulfide and 4-methyl-1,2,4-triazoline-3,5-dione identified the two components in D. elpenor lewisii as (E)-11-hexadecenal (E11–16:Ald) and (10E,12E)-10,12-hexadecadienal (E10,E12–16:Ald), and the three in T. oldenlandiae oldenlandiae as E11–16:Ald, E10,E12–16:Ald, and (10E,12Z)-10,12-hexadecadienal (E10,Z12–16:Ald). In field-trap tests, no males of either species were attracted to any single components. Male moths of D. elpenor lewisii were specifically attracted to a binary blend of E11–16:Ald and E10,E12–16:Ald at a ratio of 85:15, whereas males of T. oldenlandiae oldenlandiae were attracted to a ternary blend of E11–16:Ald, E10,Z12–16:Ald and E10,E12–16:Ald at a ratio of 30:40:30. We therefore conclude that the sex pheromone of D. elpenor lewisii is a mixture of E11–16:Ald and E10,E12–16:Ald and that of T. oldenlandiae oldenlandiae is E11–16:Ald, E10,Z12–16:Ald and E10,E12–16:Ald. 相似文献
3.
Studies of water stress commonly examine either gas exchange or leaf metabolites, and many fail to quantify the concentration of CO2 in the chloroplasts (Cc). We redress these limitations by quantifying Cc from discrimination against 13CO2 and using gas chromatography–mass spectrometry (GC–MS) for leaf metabolite profiling. Five Eucalyptus and two Acacia species from semi‐arid to mesic habitats were subjected to a 2 month water stress treatment (Ψpre‐dawn = ?1.7 to ?2.3 MPa). Carbohydrates dominated the leaf metabolite profiles of species from dry areas, whereas organic acids dominated the metabolite profiles of species from wet areas. Water stress caused large decreases in photosynthesis and Cc, increases in 17–33 metabolites and decreases in 0–9 metabolites. In most species, fructose, glucose and sucrose made major contributions to osmotic adjustment. In Acacia, significant osmotic adjustment was also caused by increases in pinitol, pipecolic acid and trans‐4‐hydroxypipecolic acid. There were also increases in low‐abundance metabolites (e.g. proline and erythritol), and metabolites that are indicative of stress‐induced changes in metabolism [e.g. γ‐aminobutyric acid (GABA) shunt, photorespiration, phenylpropanoid pathway]. The response of gas exchange to water stress and rewatering is rather consistent among species originating from mesic to semi‐arid habitats, and the general response of metabolites to water stress is rather similar, although the specific metabolites involved may vary. 相似文献
4.
Two of the ways in which plants cope with water deficits are stomatal closure and “osmotic adjustment”. We sought to assess
the contributions of these processes to maintenance of leaf hydration in field-grown, 7-year-old Eucalyptus marginata. Plants were exposed to their normal summer drought (controls) or supplied with additional water (irrigated). Irrigation
increased photosynthesis by 30% in E. marginata. These increases in photosynthesis were related to an 80% increase in g
s. However, there was no difference in substomatal CO2 concentrations between treatments, or in chloroplast CO2 concentrations, as indicated by carbon isotope composition of leaf soluble sugars. This suggests that impaired mesophyll
metabolism may partially explain slower rates of photosynthesis in plants exposed to their normal summer drought. There was
no difference in concentrations of solutes or osmotic potential between non-irrigated and irrigated individuals, perhaps because
relative water content was the same in non-irrigated and irrigated plants due to stomatal sensitivity to water deficits. Irrespective
of the absence of osmotic adjustment, analysis of leaf solutes gave a clear indication of the major groups of compounds responsible
for maintaining cell osmotic potential. Soluble sugars were three times as abundant as amino acids. Proline, a putatively
osmotically active amino acid, contributed less than 1% of total solutes. These patterns of solutes in E.
marginata are consistent with a growing body of literature arguing a greater role for carbohydrates and cyclitols and lesser role for
amino acids in maintaining osmotic potential. Our data suggest the primary mechanism by which E.
marginata coped with drought was partial stomatal closure; however, we cannot discount the possibility of osmotic adjustment under
more severe water deficits. 相似文献
5.
Summary We manipulated soil fertility and insect attack for two species of Eucalyptus in natural stands of subalpine woodland on shallow, infertile granitic soils. E. pauciflora and E. stellulata responded in similar ways to simultaneous insecticide and fertilizer treatments. Eliminating herbivorous insects produced the largest changes — improved plant growth, increased leaf N and P, and reduced leaf specific density. Fertilizer regime modified some leaf properties, but had little effect on tree growth. E. stellulata trees were initially shorter than E. pauciflora, but grew faster without herbivores; by the end of the experiment both species were the same size when herbivores were removed. Foliage N and P levels increased most in trees with the most balanced fertilizer addition (NPK), and increased in all trees protected from insects, regardless of fertilizer regime. In this system, herbivorous insects exacerbated the effects of nutrientpoor soils, and may affect dominance of Eucalyptus species in mature forests. 相似文献
6.
To understand how Mycobacterium tuberculosis (M. tuberculosis) could survive in human lung, Genomic expression library of M. tuberculosis in Escherichia coli (E. coli) had been prepared. Taking advantage of the genetic simplicity of E. coli and the functional conservation of some prokaryote proteins, a surfactant stress resistant gene Rv0621 was identified, which
encodes a 37 kDa putative membrane protein. The E. coli colony with the partial Rv0621 gene insert, named S1, was able to grow in medium containing 0.4% sodium dodecyl sulfate,
while the strain carried empty vector was unable to grow. The full length of the Rv0621 gene was then cloned into plasmid
pET32a (+) expressed in E. coli BL21 (DE3). Using gas chromatographic–mass spectrometric (GC–MS), the fatty acid composition of the E. coli BL21 (DE3) carrying Rv0621–pET32a (+) and the E. coli BL21 (DE3) carrying empty vector pET32a (+) were compared. E. coli BL21 (DE3) carrying Rv0621–pET32a (+) contained more oleic acid. This suggests the gene may be involved in regulation of
fatty acid synthesis and M. tuberculosis resistance to the surfactant defense of its host. 相似文献
7.
Laura J. Pollock Michael J. Bayly Paul G. Nevill Peter A. Vesk 《Journal of Biogeography》2013,40(1):155-167
Aim To relate genetic diversity to topographic features and to investigate genetic interactions between Eucalyptus species in a local centre of endemism and diversity in south‐eastern Australia. Location Grampian Ranges, Victoria, Australia. Methods We documented chloroplast DNA (cpDNA) variation for a group of endemic Eucalyptus species (E. serraensis, E. verrucata and E. victoriana) that dominate rocky, high‐elevation ridgelines of the Grampian Ranges and for one closely‐related, widespread species (E. baxteri) occupying flanking slopes and valleys. We documented genetic patterns across the landscape using cpDNA microsatellites, and related them to topographic features (exposed west‐facing versus protected east‐facing slopes and valleys). We also determined the extent of local haplotype sharing between populations of endemic species and neighbouring E. baxteri downslope with cpDNA microsatellites, and haplotype sharing between the endemic group and more distantly related species (E. obliqua, E. pauciflora and E. willisii) with sequences of the JLA+ chloroplast region. Results We detected 26 cpDNA microsatellite haplotypes in a relatively small area of c. 20 km × 50 km. Populations of E. baxteri on east‐facing slopes and valleys had greater cpDNA microsatellite diversity than E. baxteri and endemic species on exposed west‐facing slopes. Endemic species frequently shared chloroplast haplotypes with E. baxteri downslope. Sharing of JLA+ haplotypes with species outside the endemic group was mostly restricted to E. victoriana, which had cpDNA more similar to the species from other sections of Eucalyptus (E. obliqua, E. willisii and E. pauciflora). Main conclusions Intensive sampling of related species on small isolated mountain ranges allowed us to relate genetic diversity to fine‐scale habitats and to document extensive local haplotype sharing between species. This study contributes to a general understanding of the environmental conditions that enable plant population persistence by linking concentrations of genetic diversity to particular habitats. 相似文献
8.
Prashant Kumar Jaiswal Shweta Kohli Madhuban Gopal Indu Shekhar Thakur 《Journal of industrial microbiology & biotechnology》2011,38(4):503-511
An alkalotolerant Pseudomonas strain was enriched and isolated from effluent of the pulp and paper industry. This strain was able to degrade dibenzofuran
and utilize it as a sole source of energy and carbon. The GC–MS based detection of various intermediary metabolites of biodegradation
suggested the involvement of angular as well as lateral pathway of dibenzofuran biodegradation. The GC–MS based detection
of various intermediary metabolites of biodegradation suggested the involvement of angular as well as lateral pathway of dibenzofuran
biodegradation. This diverse dioxygenation property of the strain allowed it to utilize various recalcitrant chlorinated xenobiotics
and PAHs compounds. This strain showed optimum utilization (~85%) of dibenzofuran (200 mg l−1) within 36 h at pH 10 at 40°C. The growth of the strain was supported by a wide range of environmental conditions such as
temperature, pH, and concentration of dibenzofuran, suggesting that it can be used for in situ bioremediation of dioxin-like
compound. 相似文献
9.
Lamosa P Mingote AI Groudieva T Klippel B Egorova K Jabbour D Santos H Antranikian G 《Extremophiles : life under extreme conditions》2011,15(4):463-472
A high proportion of microorganisms that colonise cold environments originate from marine sites; hence, they must combine
adaptation to low temperature with osmoregulation. However, little or nothing is known about the nature of compatible solutes
used by cold-adapted organisms to balance the osmotic pressure of the external medium. We studied the intracellular accumulation
of small organic solutes in the Arctic isolate Carnobacterium strain 17-4 as a function of the growth temperature and the NaCl concentration in the medium. Data on 16S rDNA sequence and
DNA–DNA hybridisation tests corroborate the assignment of this isolate as a new species of the bacterial genus Carnobacterium. The growth profiles displayed maximal specific growth rate at 30°C in medium without NaCl, and maximal values of final biomass
at growth temperatures between 10 and 20°C. Therefore, Carnobacterium strain 17-4 exhibits halotolerant and psychrotolerant behaviours. The solute pool contained glycine-betaine, the main solute
used for osmoregulation, and an unknown compound whose structure was identified as α-glucopyranosyl-(1-3)-β-glucopyranosyl-(1-1)-α-glucopyranose
(abbreviated as gluconeotrehalose), using nuclear magnetic resonance and mass spectrometry. This unusual solute consistently
accumulated to high levels (0.35 ± 0.05 mg/mg cell protein) regardless of the growth temperature or salinity. The efficiency
of gluconeotrehalose in the stabilisation of four model enzymes against heat damage was also assessed, and the effects were
highly protein dependent. The lack of variation in the gluconeotrehalose content observed under heat stress, osmotic stress,
and starvation provides no clue for the physiological role of this rare solute. 相似文献
10.
Andrew Merchant Stefan K. Arndt Andrew Callister Mark A. Adams 《Environmental and Experimental Botany》2009,65(2-3):296-303
Understanding trees adaptation to arid, saline conditions is a major challenge for catchment revegetation in Australia. The accumulation of low molecular weight solutes is an established response of trees to the effects of salt and/or drought stress. Recent studies have shown that quercitol – a cyclitol – contributes significantly towards the adjustment of osmotic potential in some species of Eucalyptus. The present study investigated the role of quercitol in leaf tissues of Eucalyptus leptophylla (F. Muell) under fluctuating environmental stresses. Analysis of leaf tissues from trees growing at distances between 0 and 125 m from hyper-saline lakes suggests that quercitol contributes significantly to the adjustment of osmotic potential induced by drought in E. leptophylla. The presence of substantial concentrations of quercitol in xylem sap suggests that quercitol plays additional roles in signalling amelioration of osmotic stress in myrtaceous species. Quercitol concentrations fluctuate in both xylem and leaf tissues on a seasonal basis, suggesting a form of environmental regulation of solutes. The capacity of soil profiles to store rainwater, rather than proximity to hyper-saline groundwater largely determined osmotic stress in studied trees. Understanding such avoidance/tolerance mechanisms will be crucial to advance tree selection and breeding for stress tolerance. 相似文献
11.
Mustapha Gorai Mustapha Ennajeh Habib Khemira Mohamed Neffati 《Acta Physiologiae Plantarum》2011,33(3):963-971
The aim of this study was to investigate the effects of NaCl-salinity on the physiological attributes in common reed, Phragmites australis (Cav.) Trin. ex Steudel. Plants grew optimally under salinity treatment with standard nutrient solution without added salt
and at NaCl concentrations up to 100 mM. Applied for 21 days, NaCl-salinity (300 and 500 mM) caused a significant reduction
in growth allocation of all different tissues of P. australis. Shoot growth of reed plants displayed a highly significant correlation with plant–water relations and photosynthetic parameters.
The net photosynthetic rate and stomatal conductance of reed plants treated with NaCl-salinity at varying osmotic potential
(ψπ) of nutrient solutions were positively correlated, and the former variable also had a strong positive relationship with transpiration
rate. Leaf water potential and ψπ followed similar trends and declined significantly as ψπ of watering solutions was lowered. The increase in total inorganic nutrients resulting from increased Na+ and Cl− in all tissues and K+, Ca2+ and Mg2+ concentrations were maintained even at the most extreme salt concentration. Common reed exhibited high K+/Na+ and Ca2+/Na+ selectivity ratios over a wide range of salinities under NaCl-salinity. These findings suggest that reed plants were able
to adapt well to high salinities by lowering their leaf ψπ and the adjustment of osmotically active solutes in the leaves. 相似文献
12.
The impact of water stress was analysed in the xero-halophyte Mediterranean shrub Atriplex halimus using two Tunisian populations originating from a sub-humid coastal site (Monastir) or from a semi-arid area (Kairouan).
Seedlings were exposed for 10 days to nutrient solution containing either 0 or 15% polyethylene glycol. Water potential (Ψw), osmotic potential (Ψs), osmotic potential at full turgor [Ψs(100)], relative water content (RWC), shoot dry weight (DW) and changes in solute concentrations were quantified every 2 days
throughout the stress period and inorganic solutes contents were determined at the end of the treatment. The water deficit
induced a decrease in Ψw, Ψs and RWC in both populations, recorded changes being higher in plants of Monastir than those of Kairouan while the shoot dry
weight was reduced in a similar extent in stressed plants from both populations. Water deficit induced an increase in proline,
glycinebetaine and sugar concentrations. Proline accumulated as early as after the 24-h stress treatment while, glycinebetaine
required more than 6 days of stress to accumulate. At the end of the stress period, the plants of Kairouan population accumulated
higher amounts of proline than those of Monastir, while an opposite trend was reported for glycinebetaine. Both populations
specifically accumulated Na+ in response to drought stress, suggesting that this element could play a physiological role in the stress response of this
xero-halophyte species. Presented results suggest that the non-recyclable osmotic solute glycinebetaine does not necessarily
preferentially accumulates in population facing permanent water stress and that other strategy than osmotic adjustment might
be involved in drought tolerance of A. halimus. 相似文献
13.
To explore the significance of the ascorbate–glutathione cycle under drought stress, the leaves of 2-year-old potted apple
(Malus domestica Borkh.) plants were used to investigate the changes of each component of the ascorbate–glutathione cycle as well as the gene
expression of dehydroascorbate reductase (DHAR, EC 1.8.5.1), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase
(GR, EC 1.6.4.2) under drought stress. The results showed that the malondialdehyde (MDA) and H2O2 concentrations in apple leaves increased during drought stress and began to decrease after re-watering. The contents of total
ascorbate, reduced ascorbic acid (AsA), total glutathione and glutathione (GSH) were obviously upregulated in apple leaves
when the soil water content was 40–45%. With further increase of the drought level, the contents of the antioxidants and especially
redox state of AsA and GSH declined. However, levels of them increased again after re-watering. Moreover, drought stress induced
significant increase of the activities of enzymes such as APX, scavenging H2O2, and also of monodehydroascorbate reductase (MDHAR, EC 1.6.5.4), DHAR and GR used to regenerate AsA and GSH, especially when
the soil water content was above 40–45%. During severe drought stress, activities of the enzymes were decreased and after
re-watering increased again. Gene expression of cytoplasmic DHAR, cytoplasmic APX and cytoplasmic GR showed similar changes as the enzyme activities, respectively. The results suggest that the ascorbate–glutathione cycle is
up-regulated in response to drought stress, but cannot be regulated at severe drought stress conditions. 相似文献
14.
Basharat Ali Anjum Nasim Sabri Karin Ljung Shahida Hasnain 《World journal of microbiology & biotechnology》2009,25(3):519-526
Sixteen Bacillus strains isolated from rhizosphere, histoplane and phyllosphere of different plant species were identified by 16S rDNA gene
sequencing and evaluated for in vitro auxin production as well as growth stimulation of Vigna radiata (L.) Wilczek. Auxin production by Bacillus spp. in L-broth medium supplemented with 1,000 μg ml−1
L-tryptophan ranges from 0.60 to 3.0 μg IAA ml−1 as revealed by gas chromatography and mass spectrometric (GC–MS) analysis. Rhizospheric isolates exhibit relatively more
IAA synthesis than histoplane and phyllosphere isolates. Plant microbe interaction experiments conducted under gnotobiotic
conditions recorded 55.55, 46.46 and 46.20% increase in shoot length with Bacillus megaterium MiR-4, B. pumilus NpR-1 and B. subtilis TpP-1, respectively, over control. Bacillus inoculations also increased shoot fresh weight with B. megaterium MiR-4 (60.94%) and B. pumilus NpR-1 (37.76%). Highly significant positive correlation between auxin production analyzed by GC–MS and shoot length (r = 0.687**, P = 0.01) and shoot fresh weight (r = 0.703**, P = 0.01) was noted under gnotobiotic conditions. Similarly, significant correlation was also found between auxin production
by Bacillus spp. (GC–MS analysis) and different growth parameters such as shoot length (r = 0.495*, P = 0.05), number of pods (r = 0.498*, P = 0.05) and grain weight (r = 0.537*, P = 0.05) at full maturity under natural wire house conditions. Results showed that auxin production potential of plant associated
Bacillus spp. can be effectively exploited to enhance the growth and yield of V. radiata. 相似文献
15.
I. Poirier P.-A. Maréchal C. Evrard P. Gervais 《Applied microbiology and biotechnology》1998,50(6):704-709
Escherichia coli and Lactobacillus plantarum were subjected to final water potentials of −5.6 MPa and −11.5 MPa with three solutes: glycerol, sorbitol and NaCl. The water
potential decrease was realized either rapidly (osmotic shock) or slowly (20 min) and a difference in cell viability between
these conditions was only observed when the solute was NaCl. The cell mortality during osmotic shocks induced by NaCl cannot
be explained by a critical volume decrease or by the intensity of the water flow across the cell membrane. When the osmotic
stress is realized with NaCl as the solute, in a medium in which osmoregulation cannot take place, the application of a slow
decrease in water potential resulted in the significant maintenance of cell viability (about 70–90%) with regard to the corresponding
viability observed after a sudden step change to same final water potential (14–40%). This viability difference can be explained
by the existence of a critical internal free Na+ concentration.
Received: 20 May 1998 / Received revision: 31 July 1998 / Accepted: 31 July 1998 相似文献
16.
Gas exchange,chlorophyll fluorescence,and osmotic adjustment in two mango cultivars under drought stress 总被引:1,自引:0,他引:1
The responses of photosynthetic gas exchange, chlorophyll fluorescence, content of pigments, main osmolytes, and malondialdehyde
(MDA) to water-withholding for 15 days and re-hydration in seedlings of two mango cultivars (Mangifera indica L. var. “Choke Anand’ and var. “Khieo Sawoei”) under 50% sunlight and full sunlight were investigated. For both cultivars, the water-witholding resulted
in progressively decreases in leaf relative water content, net photosynthesis (P
n), stomatal conductance (g
s), and increases in the conversion of xanthophyll cycle pigments estimated by an index of leaf spectral reflectance (ΔPRI),
carotenoid to chlorophyll ratio, non-photochemical quenching (NPQ), the contents of malondialdehyde (MDA) and compatible solutes
(total soluble sugar and proline). The effect of the water stress was more pronounced in full sunlight than 50% sunlight.
The maximum photochemistry efficiency measured at dawn was fairly constant during the period of the treatment for both cultivars
under both light regimes. The water stress caused less pronounced inhibition of photosynthesis in “Choke Anand” than in “Khieo
Sawoei” cultivar under both light regimes. After re-hydration, the recovery was relatively quicker in “Choke Anand” than in
“Khieo Sawoei” cultivar. Both cultivars in both 50% and full sunlight showed complete recovery in photochemistry after 5 days
of re-watering but photosynthesis did not show a complete recovery as indicated by gas exchange rates. As the results of lower
NPQ, ΔPRI and osmotic adjustment in the cultivar “Khieo Sawoei” compared to the cultivar “Choke Anand”, the former cultivar
was less tolerant to drought than the latter. Our study further showed that partial shading (e.g., 50% of sunlight) significantly
alleviated the harmful effect of drought stress on mango cultivars but in fact stomata of seedlings grown in partial shade
was more responsive to water deficit than in full light. 相似文献
17.
Rui-Yu Zhao Wei Xiao Hai-Li Cheng Ping Zhu Ke-Di Cheng 《Journal of industrial microbiology & biotechnology》2010,37(11):1171-1182
The gene encoding squalene synthase (GfSQS) was cloned from Fusarium fujikuroi (Gibberella fujikuroi MP-C) and characterized. The cloned genomic DNA is 3,267 bp in length, including the 5′-untranslated region (UTR), 3′-UTR,
four exons, and three introns. A noncanonical splice-site (CA-GG, or GC-AG) was found at the first intron. The open reading
frame of the gene is 1,389 bp in length, corresponding to a predicted polypeptide of 462 amino acid residues with a MW 53.4 kDa.
The predicted GfSQS shares at least four conserved regions involved in the enzymatic activity with the SQSs of varied species.
The recombinant protein was expressed in E. coli and detected by SDS–PAGE and western blot. GC–MS analysis showed that the wild-type GfSQS could catalyze the reaction from
farnesyl diphosphate (FPP) to squalene, while the mutant mGfSQS (D82G) lost total activity, supporting the prediction that
the aspartate-rich motif (DTXED) in the region I of SQS is essential for binding of the diphosphate substrate. 相似文献
18.
Buprofezin is a widely used insecticide that has caused environmental pollution in many areas. However, biodegradation of
buprofezin by pure cultures has not been extensively studied, and the transformation pathway of buprofezin remains unclear.
In this paper, a buprofezin co-metabolizing strain of DFS35-4 was isolated from a buprofezin-polluted soil in China. Strain
DFS35-4 was preliminarily identified as Pseudomonas sp. based on its morphological, physiological, and biochemical properties, as well as 16S rRNA gene analysis. In the presence
of 2.0 g l−1 sodium citrate, strain DFS35-4 degraded over 70% of 50 mg l−1 buprofezin in 3 days. Strain DFS35-4 efficiently degraded buprofezin in the pH range of 5.0–10.0 and at temperatures between
20 and 30°C. Three metabolites, 2-imino-5-phenyl-3-(propan-2-yl)-1,3,5-thiadiazinan-4-one, 2-imino-5-phenyl-1,3,5-thiadiazinan-4-one,
and methyl(phenyl) carbamic acid, were identified during the degradation of buprofezin using gas chromatography–mass spectrometry
(GC–MS) and tandem mass spectrometry (MS/MS). A partial transformation pathway of buprofezin in Pseudomonas sp. DFS35-4 was proposed based on these metabolites. 相似文献
19.
Koek MM van der Kloet FM Kleemann R Kooistra T Verheij ER Hankemeier T 《Metabolomics : Official journal of the Metabolomic Society》2011,7(1):1-14
Due to the complexity of typical metabolomics samples and the many steps required to obtain quantitative data in GC × GC–MS
consisting of deconvolution, peak picking, peak merging, and integration, the unbiased non-target quantification of GC × GC–MS
data still poses a major challenge in metabolomics analysis. The feasibility of using commercially available software for
non-target processing of GC × GC–MS data was assessed. For this purpose a set of mouse liver samples (24 study samples and
five quality control (QC) samples prepared from the study samples) were measured with GC × GC–MS and GC–MS to study the development
and progression of insulin resistance, a primary characteristic of diabetes type 2. A total of 170 and 691 peaks were quantified
in, respectively, the GC–MS and GC × GC–MS data for all study and QC samples. The quantitative results for the QC samples
were compared to assess the quality of semi-automated GC × GC–MS processing compared to targeted GC–MS processing which involved
time-consuming manual correction of all wrongly integrated metabolites and was considered as golden standard. The relative
standard deviations (RSDs) obtained with GC × GC–MS were somewhat higher than with GC–MS, due to less accurate processing.
Still, the biological information in the study samples was preserved and the added value of GC × GC–MS was demonstrated; many
additional candidate biomarkers were found with GC × GC–MS compared to GC–MS. 相似文献
20.
Symbiotic effectiveness and response to mannitol-mediated osmotic stress of various chickpea–rhizobia associations 总被引:1,自引:1,他引:0
Haythem Mhadhbi Moez Jebara Adel Zitoun Férid Limam Mohamed Elarbi Aouani 《World journal of microbiology & biotechnology》2008,24(7):1027-1035
Thirty-six symbiotic associations involving six chickpea cultivars against six rhizobial strains were evaluated for symbiotic
performance and responses to osmotic stress applied by mannitol (50 mM) in aerated hydroponic cultures. Analyses in different
symbioses were focused on biomass production, nodulation, nitrogen fixation, and their modulation under osmotic stress conditions,
as well as expression of nodular antioxidant enzymes. Mesorhizobium ciceri reference (835) and local (CMG6) strains, as well as the local (C11) M. mediterraneum allowed the best symbiotic efficiency for all chickpea cultivars. The osmotic stress induces severe decrease ranging 30–50%
in aerial biomass and 50–70% for nitrogen fixation. Nevertheless, plants inoculated with M. ciceri (835) and M. mediterraneum (C11) preserve a relatively high growth (4 g plant−1) with nitrogen-fixing activity (25 μmols h−1 plant−1). The bacterial partner was the most important factor of variance of the analysed parameters in osmotic stress or physiological
conditions where it gets to 60–85%. The strains allowing the best competent symbioses were proposed for field assays. Under
osmotic stress, nodular peroxidase (POX) and ascorbate peroxidase (APX) activities were significantly enhanced. The increase
of POX and APX was inversely correlated with the inhibition of aerial biomass production (p = 0.05) and nitrogen-fixing capacity (p = 0.01), suggesting a protective role of these enzymes in nodules. Superoxide dismutase (SOD) was also activated in stressed
nodules. However, the spectacular decrease in catalase (CAT) activity discounts its involvement in osmotic stress response. 相似文献