排序方式: 共有16条查询结果,搜索用时 15 毫秒
1.
Enhanced bioremediation of n-alkane in petroleum sludge using bacterial consortium amended with rhamnolipid and micronutrients 总被引:9,自引:0,他引:9
Rahman KS Rahman TJ Kourkoutas Y Petsas I Marchant R Banat IM 《Bioresource technology》2003,90(2):159-168
The purpose of the present study was to investigate possible methods to enhance the rate of biodegradation of oil sludge from crude oil tank bottom, thus reducing the time usually required for bioremediation. Enhancement of biodegradation was achieved through bioaugmentation and biostimulation. About 10% and 20% sludge contaminated sterile and non-sterile soil samples were treated with bacterial consortium (BC), rhamnolipid biosurfactant (RL) and nitrogen, phosphorus and potassium (NPK) solution. Maximum n-alkane degradation occurred in the 10% sludge contaminated soil samples. The effects of treatment carried out with the non-sterile soil samples were more pronounced than in the sterile soils. Maximum degradation was achieved after the 56th day of treatment. n-Alkanes in the range of nC8-nC11 were degraded completely followed by nC12-nC21, nC22-nC31 and nC32-nC40 with percentage degradations of 100%, 83-98%, 80-85% and 57-73% respectively. Statistical analysis using analysis of variance and Duncan's multiple range test revealed that the level of amendments, incubation time and combination of amendments significantly influenced bacterial growth, protein concentration and surface tension at a 1% probability level. All tested additives BC, NPK and RL had significant positive effects on the bioremediation of n-alkane in petroleum sludge. 相似文献
2.
3.
The evolutionary origin of the pinnipeds (seals, sea lions, and walruses)
is still uncertain. Most authors support a hypothesis of a monophyletic
origin of the pinnipeds from a caniform carnivore. A minority view suggests
a diphyletic origin with true seals being related to the mustelids (otters
and ferrets). The phylogenetic relationships of the walrus to other
pinniped and carnivore families are also still particularly problematic.
Here we examined the relative support for mono- and diphyletic hypotheses
using DNA sequence data from the mitochondrial small subunit (12S) rRNA and
cytochrome b genes. We first analyzed a small group of taxa representing
the three pinniped families (Phocidae, Otariidae, and Odobenidae) and
caniform carnivore families thought to be related to them. We inferred
phylogenetic reconstructions from DNA sequence data using standard
parsimony and neighbor-joining algorithms for phylogenetic inference as
well as a new method called spectral analysis (Hendy and Penny) in which
phylogenetic information is displayed independently of any selected tree.
We identified and compensated for potential sources of error known to lead
to selection of incorrect phylogenetic trees. These include sampling error,
unequal evolutionary rates on lineages, unequal nucleotide composition
among lineages, unequal rates of change at different sites, and
inappropriate tree selection criteria. To correct for these errors, we
performed additional transformations of the observed substitution patterns
in the sequence data, applied more stringent structural constraints to the
analyses, and included several additional taxa to help resolve long,
unbranched lineages in the tree. We find that there is strong support for a
monophyletic origin of the pinnipeds from within the caniform carnivores,
close to the bear/raccoon/panda radiation. Evidence for a diphyletic origin
was very weak and can be partially attributed to unequal nucleotide
compositions among the taxa analyzed. Subsequently, there is slightly more
evidence for grouping the walrus with the eared seals versus the true
seals. A more conservative interpretation, however, is that the walrus is
an early, but not the first, independent divergence from the common
pinniped ancestor.
相似文献
4.
I. Petsas K. Psarianos A. Bekatorou A.A. Koutinas I.M. Banat R. Marchant 《Biotechnology letters》2002,24(7):557-560
A commercial culture of Kefir grew well at 30°C and 37°C with NaCl up to 4% (w/v) but at 42°C and 4% (w/v) NaCl it grew very slowly. These conditions were selected for the mutation with N-methyl-N-nitrosoguanidine in order to improve cell yield at high temperatures and salt concentration. The mutated cells had higher biomass and growth rate compared with the original culture. The improvement of Kefir at high temperatures and salt concentrations offers advantages for uses in single cell protein production and alcohol production from whey containing high salt. 相似文献
5.
6.
Phlomis fruticosa is one of the main species of post-fire Mediterranean communities, occupying areas with post-fire grazing or altered precipitation
pattern and consequently water stress imposed on seedlings of co-occurring species. Seedlings of woody perennials often differ
from their mature individuals regarding their resistance of photosynthetic performance to environmental stresses. Such differences
have been reported for tree species but there is a lack of information regarding shrub species. In the present study, we tried
to detect changes in (PSII) activity imposed by water stress in P. fruticosa seedlings as well as its capability for recovery after rehydration. Maximum PSII photochemical efficiency decreased only
under severe water stress exactly as in mature plants in the field. However, leaf chlorophyll (Chl) content was almost stable
regardless of leaf relative water content (RWC). We assume that the photoprotective chlorophyll loss process, reported for
many mature Mediterranean species (including P. fruticosa), has not yet been developed at the seedling stage. On the other hand, photoprotection through an increase of the relative
amount of non-QB-reducing centers was found during dehydration. Non-photochemical quenching (NPQ) contributed to protection from photodamage
until moderate water stress but was significantly suppressed under severe water stress. Both processes were reversed after
rehydration. The above characteristics enabled seedlings not only to survive during aggravating drought but also to maintain
a considerable part of their effective quantum yield and perform significant electron transport even at extremely low relative
water content (RWC). This was confirmed with measurements in a semi-natural environment (pots) and under real steady state
conditions regarding adaptation of the photosynthetic machinery to prevailing light intensities. 相似文献
7.
Nikolaos Petsas Emanuele Tinelli Delia Lenzi Valentina Tomassini Emilia Sbardella Francesca Tona Eytan Raz Valter Nucciarelli Carlo Pozzilli Patrizia Pantano 《PloS one》2013,8(6)
Objectives
Examination of sensorimotor activation alone in multiple sclerosis (MS) patients may not yield a comprehensive view of cerebral response to task stimulation. Additional information may be obtained by examining the negative BOLD response (deactivation). Aim of this work was to characterize activation and deactivation patterns during passive hand movements in MS patients.Methods
13 relapsing remitting-MS patients (RRMS), 18 secondary progressive-MS patients (SPMS) and 15 healthy controls (HC) underwent an fMRI study during passive right-hand movements. Activation and deactivation contrasts in the three groups were entered into ANOVA, age and gender corrected. Post-hoc analysis was performed with one-sample and two-sample t-tests. For each patient we obtained lesion volume (LV) from both T1- and T2-weighted images.Results
Activations showed a progressive extension to the ipsilateral brain hemisphere according to the group and the clinical form (HC<RRMS<SPMS). Significant deactivation of the ipsilateral cortical sensorimotor areas was reduced in both patient groups with respect to HC. Deactivation of posterior cortical areas belonging to the default mode network (DMN), was increased in RRMS, but not in SPMS, with respect to HC. The amount of activation in the contralateral sensorimotor cortex was significantly correlated with that of deactivation in the DMN in HC and RRMS, but not in SPMS. Both increased activation and decreased deactivation patterns correlated with LV.Conclusion
In RRMS patients, increased cortical activation was associated with increased deactivation of the posterior cortex suggesting a greater resting-state activity in the DMN, probably aimed at facilitating sensorimotor circuit engagement during task performance. In SPMS the coupling between increased sensorimotor activation/increased DMN deactivation was not observed suggesting disorganization between anticorrelated functional networks as a consequence of a higher level of disconnection. 相似文献8.
9.
A. Makrigiannakis M. Karamouti G. Petsas N. Makris G. Nikas A. Antsaklis 《Histochemistry and cell biology》2009,132(2):159-167
Pinopodes represent the morphological and integrins, the biomollecular markers of endometrial receptivity. We studied using
scanning electron microscopy, the expression of pinopodes on tubal samples and their corresponding endometria, from 21 women
of reproductive age (7 from proliferative phase, 7 from day LH +5 and 7 from day LH +7). In addition, we examined the immunohistochemical
staining of integrins αvβ3, αvβ5 and their ligands, fibronectin (FN) and osteopontin (OPN) in the same tubal epithelium samples.
Pinopodes were detected on the tubal epithelium exclusively during day LH +7, coincident with their formation in the endometrium
and synchronous to αvβ3 sharp increase in the oviduct epithelium, suggesting a regulation similar to the endometrium. In contrast,
αvβ5, FN and OPN remained unchanged during the cycle. These results show for the first time the formation of pinopodes in
the tubal epithelium at the time of endometrial receptivity and correlate it with the upregulation of the intact dimmer αvβ3
in the tubes. 相似文献
10.
Stuart A Suttie Alan GK Li Martha Quinn Kenneth GM Park 《World journal of surgical oncology》2007,5(1):1-9