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1.
Two thermophilic anaerobic bacterial consortia (ALK-1 and LLNL-1), capable of degrading the aromatic fuel hydrocarbons, benzene,
toluene, ethylbenzene, and the xylenes (BTEX compounds), were developed at 60 °C from the produced water of ARCO'S Kuparuk
oil field at Alaska and the subsurface water at the Lawrence Livermore National Laboratory gasoline-spill site, respectively.
Both consortia were found to grow at 45–75 °C on BTEX compounds as their sole carbon and energy sources with 50 °C being the
optimal temperature. With 3.5 mg total BTEX added to sealed 50-ml serum bottles, which contained 30 ml mineral salts medium
and the consortium, benzene, toluene, ethylbenze, m-xylene, and an unresolved mixture of o- and p-xylenes were biodegraded by 22%, 38%, 42%, 40%, and 38%, respectively, by ALK-1 after 14 days of incubation at 50 °C. Somewhat
lower, but significant, percentages of the BTEX compounds also were biodegraded at 60 °C and 70 °C. The extent of biodegradation
of these BTEX compounds by LLNL-1 at each of these three temperatures was slightly less than that achieved by ALK-1. Use of
[ring-14C]toluene in the BTEX mixture incubated at 50 °C verified that 41% and 31% of the biodegraded toluene was metabolized within
14 days to water-soluble products by ALK-1 and LLNL-1, respectively. A small fraction of it was mineralized to 14CO2. The use of [U-14C]benzene revealed that 2.6%–4.3% of the biodegraded benzene was metabolized at 50 °C to water-soluble products by the two
consortia; however, no mineralization of the degraded [U-14C]benzene to 14CO2 was observed. The biodegradation of BTEX at all three temperatures by both consortia was tightly coupled to sulfate reduction
as well as H2S generation. None was observed when sulfate was omitted from the serum bottles. This suggests that sulfate-reducing bacteria
are most likely responsible for the observed thermophilic biodegradation of BTEX in both consortial cultures.
Received: 12 July 1996 / Received revision: 31 December 1996 / Accepted: 31 January 1997 相似文献
2.
In this study, we investigated the treatability of co-mingled groundwater contaminated with polycyclic aromatic hydrocarbons
(PAHs), gasoline hydrocarbons, and methyl tert-butyl ether (MtBE) using an ex-situ aerobic biotreatment system. The PAHs of interest were naphthalene, methyl-naphthalene, acenaphthene, acenaphthylene, and
carbazole. The gasoline hydrocarbons included benzene, toluene, ethyl benzene, and p-xylene (BTEX). Two porous pot reactors were operated for a period of 10 months under the same influent contaminant concentrations.
The contaminated groundwater was introduced into the reactors at a flow rate of 4 and 9 l/day, resulting in a hydraulic retention
time (HRT) of 32 and 15 h, respectively. In both reactors, high removal efficiencies were achieved for the PAHs (>99%), BTEX
and MtBE (>99.7%). All the PAHs of interest and the four BTEX compounds were detected at concentrations less than 1 μg/l throughout
the study duration. Effluent MtBE from both reactors was observed at higher levels; nevertheless, its concentration was lower
than the 5 μg/l Drinking Water Advisory for MtBE implemented in California. 相似文献
3.
Pakala SB Gorla P Pinjari AB Krovidi RK Baru R Yanamandra M Merrick M Siddavattam D 《Applied microbiology and biotechnology》2007,73(6):1452-1462
A soil bacterium capable of utilizing methyl parathion as sole carbon and energy source was isolated by selective enrichment
on minimal medium containing methyl parathion. The strain was identified as belonging to the genus Serratia based on a phylogram constructed using the complete sequence of the 16S rRNA. Serratia sp. strain DS001 utilized methyl parathion, p-nitrophenol, 4-nitrocatechol, and 1,2,4-benzenetriol as sole carbon and energy sources but could not grow using hydroquinone
as a source of carbon. p-Nitrophenol and dimethylthiophosphoric acid were found to be the major degradation products of methyl parathion. Growth on
p-nitrophenol led to release of stoichiometric amounts of nitrite and to the formation of 4-nitrocatechol and benzenetriol.
When these catabolic intermediates of p-nitrophenol were added to resting cells of Serratia sp. strain DS001 oxygen consumption was detected whereas no oxygen consumption was apparent when hydroquinone was added to
the resting cells suggesting that it is not part of the p-nitrophenol degradation pathway. Key enzymes involved in degradation of methyl parathion and in conversion of p-nitrophenol to 4-nitrocatechol, namely parathion hydrolase and p-nitrophenol hydroxylase component “A” were detected in the proteomes of the methyl parathion and p-nitrophenol grown cultures, respectively. These studies report for the first time the existence of a p-nitrophenol hydroxylase component “A”, typically found in Gram-positive bacteria, in a Gram-negative strain of the genus
Serratia.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
4.
Microrheological properties (aggregation and deformability) of erythrocytes separated by centrifugation at 30000×g density gradient into “young” and “old” (the upper and lower fractions, respectively) were studied. The erythrocytes were
taken from physically active persons (PAP) and from those with elevated arterial pressure (EAP). A significant difference
in microrheological properties of the “young” and “old” erythrocytes was found. The aggregation degree of “old” cells was
nearly twice that of “young” cells. The deformability of the erythrocyte subpopulations was significantly different, though
the difference was not so pronounced as in the case of aggregation. The aggregation of “young” and “old” erythrocytes in the
PAP group was the least (28% lower than in the control). Note, that “old” erythrocytes in the PAP group had better microrheological
properties than in the other groups. All erythrocyte populations in the EAP group were characterized by higher aggregation,
decreased deformability, and decreased capacity for oxygen transport. 相似文献
5.
The fundatrix ofCeratovacuna nekoashi attacks an axillary bud ofStyrax japonica to form a “cat's-paw” gall with a number of completely closed subgalls. Larvae produced early by the fundatrix enter subgalls,
but late-produced ones cannot because the subgalls close too early. The average number of these “outsiders” produced per gall
was 3.81±2.37 (n=26). In spite of their small numbers, outsiders attacked caterpillars placed on the gall. Thus outsiders
function to defend their gall against external attacks such as those from lepidopterous predators. 相似文献
6.
A. J. Willetts 《Antonie van Leeuwenhoek》1973,39(1):585-597
A study was made of the biodegradation of 1-phenylundecane-p-sulphonate and 1-phenyldodecane-p-sulphonate byCladosporium resinae (CMI 88968) which was capable of growth on a number of such alkylbenzene sulphonate homologues as the sole source of carbon
and sulphur. The results from both whole-cell and cell-free systems indicated that the alkyl, aryl and sulphonate moieties
of detergent homologues were metabolised by the fungus. The alkyl side-chain, after a presumed initial oxidation of the terminal
methyl group, was subsequently oxidised by a β-oxidation pathway. Three enzymes of the β-oxidation pathway, i.e. acyl-CoA
synthetase, acyl-CoA dehydrogenase and β-hydroxyacyl-CoA dehydrogenase were identified in detergent-grown cell-free extracts
of the fungus. The sulphonate moiety was released as sulphate by a desulphonating enzyme. The combined results of continuous
sampling programmes monitored by both TLC and sulphate appearance in the growth medium indicated that desulphonation of the
aromatic moiety was an early event in the overall biodegradation of synthetic detergent homologues. The presence of 1-phenylvalerate,
1-phenylpropionate, benzoate,p-hydroxybenzoate and 3,4-dihydroxybenzoate in cells after growth on 1-phenylundecane-p-sulphonate was indicated by GLC analysis. Cells grown on 1-phenyldodecane-p-sulphonate were shown to contain 1-phenylhexanoate, 1-phenylbutyrate, phenylacetate,p-hydroxyphenylacetate and 3,4-dihydroxyphenylacetate. The aromatic nuclei remaining after alkyl side-chain biodegradation
were further metabolised by an oxidation sequence involving an “ortho-cleavage” pathway. An overall metabolic pathway for
the biodegradation of alkylbenzene sulphonates byCladosporium resinae is proposed. 相似文献
7.
Madoka Y Kashiwagi T Hirotsu N Ishimaru K 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,116(5):603-612
Rice (Oryza sativa L.) chromosome segment substitution lines (CSSLs), in which chromosomal segments of the Indian landrace “Kasalath” replace
the corresponding endogenous segments in the genome of the Japanese premium rice “Koshihikari”, are available and together
cover the entire genome. Chromosome regions affecting a trait (CRATs) can be identified by comparison of phenotypes with genotypes of CSSLs. We detected 99 CRATs for 15 agronomic
or morphological traits. “Kasalath” had positively acting alleles in 53 CRATs. Its CRATs increased panicle number per plant
by up to 23.3%, grain number per panicle by up to 30.8%, and total grain number by up to 15.1%, relative to “Koshihikari”.
CRATs were identified for grain size (grain thickness and width), with positive effects of about 5.0%. A CRAT on chromosome 8
almost doubled the weight of roots in uppermost soil layers compared to “Koshihikari”. Additionally, “Kasalath” possessed
CRATs for higher lodging resistance (reduction in plant height and increase in stem diameter). In some cases, multiple CRATs
were detected in the same chromosome regions. Therefore, CSSLs with these chromosome segments might be useful breeding materials
for the simultaneous improvement of multiple traits. Five CRATs, one for plant height on chromosome 1, one for stem diameter
on chromosome 8, and three for heading date on chromosomes 6, 7, and 8 overlapped with the corresponding QTLs that already
had been mapped with back-crossed inbred lines of “Nipponbare” and “Kasalath”. In both “Koshihikari” CRATs and “Nipponbare”
QTLs, “Kasalath” had similar effects.
Both Y. Madoka and T. Kashiwagi have contributed equally to this article. 相似文献
8.
The present work describes investigations on the bacterial degradation of the alicyclic molecule cyclododecane. It represents
a structure where the initial degradative steps have to be similar to a “subterminal” attack as there is no “terminal” part
of the molecule. We were able to show that the gram-positive bacterium Rhodococcus ruber CD4 DSM 44394 oxidizes cyclododecane to the corresponding alcohol and ketone, the latter being subject to ring fission by
a Baeyer-Villiger oxygenase. This key enzyme is an NADPH- and O2-dependent flavoprotein with a substrate specificity for bigger rings. The further metabolism of the resulting lactone gives
rise to an ω-hydroxyalkanoic acid that is susceptible to common β-oxidation. Due to its alicyclic character and its ring size,
cyclododecane is comparable to aliphatic bridge components that are an important element in the coal texture. They contribute
to the three-dimensional coal structure and thus could serve as a valuable target for the oxidative abilities of R. ruber CD4 to reduce the molecular mass of coal.
Received: 2 July 1998 / Received revision: 27 October 1998 / Accepted: 30 October 1998 相似文献
9.
10.
The resurgence of interest in tumor metabolism has led investigators to emphasize the metabolism of proline as a “stress substrate”
and to suggest this pathway as a potential anti-tumor target. Proline oxidase, a.k.a. proline dehydrogenase (POX/PRODH), catalyzes
the first step in proline degradation and uses proline to generate ATP for survival or reactive oxygen species for programmed
cell death. POX/PRODH is induced by p53 under genotoxic stress and initiates apoptosis by both mitochondrial and death receptor
pathways. Furthermore, POX/PRODH is induced by PPARγ and its pharmacologic ligands, the thiazolidinediones. The anti-tumor
effects of PPARγ may be critically dependent on POX/PRODH. In addition, it is upregulated by nutrient stress through the mTOR
pathway to maintain ATP levels. We propose that proline is made available as a stress substrate by the degradation of collagen
in the microenvironmental extracellular matrix by matrix metalloproteinases. In a manner analogous to autophagy, this proline-dependent
process for bioenergetics from collagen in extracellular matrix can be designated “ecophagy”. 相似文献
11.
Inventory, differentiation, and proportional diversity: a consistent terminology for quantifying species diversity 总被引:1,自引:0,他引:1
Almost half a century after Whittaker (Ecol Monogr 30:279–338, 1960) proposed his influential diversity concept, it is time
for a critical reappraisal. Although the terms alpha, beta and gamma diversity introduced by Whittaker have become general textbook knowledge, the concept suffers from several drawbacks. First, alpha
and gamma diversity share the same characteristics and are differentiated only by the scale at which they are applied. However,
as scale is relative––depending on the organism(s) or ecosystems investigated––this is not a meaningful ecological criterion.
Alpha and gamma diversity can instead be grouped together under the term “inventory diversity.” Out of the three levels proposed
by Whittaker, beta diversity is the one which receives the most contradictory comments regarding its usefulness (“key concept”
vs. “abstruse concept”). Obviously beta diversity means different things to different people. Apart from the large variety
of methods used to investigate it, the main reason for this may be different underlying data characteristics. A literature
review reveals that the multitude of measures used to assess beta diversity can be sorted into two conceptually different
groups. The first group directly takes species distinction into account and compares the similarity of sites (similarity indices,
slope of the distance decay relationship, length of the ordination axis, and sum of squares of a species matrix). The second
group relates species richness (or other summary diversity measures) of two (or more) different scales to each other (additive
and multiplicative partitioning). Due to that important distinction, we suggest that beta diversity should be split into two
levels, “differentiation diversity” (first group) and “proportional diversity” (second group). Thus, we propose to use the
terms “inventory diversity” for within-sample diversity, “differentiation diversity” for compositional similarity between
samples, and “proportional diversity” for the comparison of inventory diversity across spatial and temporal scales.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
13.
Masayoshi Maehata 《Ichthyological Research》2001,48(3):283-287
The mating behavior of the rock catfish Silurus lithophilus (Siluriformes: Siluridae), a species endemic to the Lake Biwa system, was observed from May to July in 1989–1994 along the
rocky shore of the lake's outlet, the Seta River. The mating behavior of S. lithophilus involved a certain behavioral sequence: “chasing,”“clinging,” and “enfolding” while “squeezing” by the male; and “circling”
by the spawned pair. The mating behavior of this species was basically similar to that of S. biwaensis, but greatly different from that of S. asotus, which spawns in running water (in ditches). The mating behavior of S. lithophilus (and S. biwaensis) might have developed as an adaptation to lentic environments such as the shores of the large river or the lake.
Received: October 25, 2000 / Revised: February 25, 2001 / Accepted: March 8, 2001 相似文献
14.
Singh AK Chaudhary P Macwan AS Diwedi UN Kumar A 《Applied microbiology and biotechnology》2007,76(4):895-901
The chlorinated insecticide γ-hexachlorocyclohexane (γ-HCH) is sequentially metabolized by the products of linA, linB, linC, linD, linE, and linF genes to β-ketoadipate, which is subsequently mineralized. Two or more copies of these genes are present in the bacterium
Pseudomonas aeruginosa ITRC-5 that was isolated earlier by selective enrichment on technical-HCH. At least one copy of linA, linB, linC, linD, and possibly linE is lost from ITRC-5 upon its growth on γ-HCH. All the lin genes, however, are lost when the bacterium was grown in Luria–Bertani (LB) medium. The loss of lin genes is accompanied with the loss/rearrangement of insertion sequence IS6100 genes. Concomitant to the loss of lin genes, the degradation of HCH-isomers by “γ-HCH grown cells” is slower, when compared with “technical-HCH grown cells”, and
is completely lost by “LB-grown cells”. The selective loss of lin genes during different growth conditions has not been reported before and is expected to help in understanding the dynamism
of degradative genes. 相似文献
15.
Somaclonal variation in oil palm (Elaeis guineensis Jacq.): the DNA methylation hypothesis 总被引:2,自引:0,他引:2
Elaeis guineensis Jacq.) currently hampers the scaling-up of clonal plant production. In order to investigate the relationship between the
“mantled” somaclonal variant and possible alterations in genomic DNA methylation rate, two complementary approaches have been
used. HPLC quantification of relative amounts of 5-methyl-deoxycytidine has shown that global methylation in leaf DNA of abnormal
regenerants is 0.5–2.5% lower than in their normal counterparts (20.8% vs 22%, respectively). When comparing nodular compact
calli and fast growing calli, yielding respectively 5% and 100% of “mantled” plantlets, this decrease was up to 4.5% (from
23.2 to 18.7%). An alternative method, the SssI-methylase accepting assay, based on the enzymatic saturation of CG sites with methyl groups, gave convergent results. This
work demonstrates that a correlation exists between DNA hypomethylation and the “mantled” somaclonal variation in oil palm.
Received: 9 July 1999 / Revision received: 15 October 1999 / Accepted: 26 October 相似文献
16.
François Mankessi Aubin R. Saya Frédéric Boudon Yann Guédon Fabienne Montes Marc Lartaud Jean-Luc Verdeil Olivier Monteuuis 《Trees - Structure and Function》2010,24(4):743-752
Shoot apical meristem (SAM) domes derived from five different outdoor and in vitro sources of juvenile and mature Eucalyptus urophylla × Eucalyptus grandis akin genotypes were compared. Overall measurements of SAM dome height H and diameter D ranged from 2 to 35 μm and 20 to 80 μm, with significant differences according to the various physiological origins of plant
material investigated. SAM domes from the mature trees “Mat” were taller than those from the rejuvenated ministock plants
“Rej”; from the in vitro microcuttings “IVM” of the same clone and also from the in vitro juvenile seedlings “IVJ”, whereas
outdoor seedlings “Juv” exhibited intermediate SAM dome height. SAM domes from the rejuvenated material “Rej”, from the in
vitro mature “IVM” and juvenile “IVJ” origins were also narrower than those from the outdoor seedlings “Juv” and to lesser
extent than those from the mature trees “Mat”. Overall, the mature source “Mat” displayed bigger and somehow sharper hemispherical
domes than those from “Rej” and “Juv”, physiologically more juvenile, or those from the in vitro origins “IVM” and “IVJ” which
looked flatter and smaller. SAM dome height, diameter D and H/D values varied also significantly according to the plastochron. More specifically, H, D, and H/D SAM differences between the five origins were not significant during the early plastochron phase corresponding to leaf initiation,
to become more salient as leaf structures started to elongate and to differentiate. This was particularly obvious for mature
tree “Mat” SAM dome shapes which showed at this stage much higher H/D values than the other SAM sources. A shape index S used for characterizing more accurately dome shape confirmed these trends. These observations provide additional arguments
to the view that juvenility in trees becomes more and more time- and shoot-tip restricted as ageing increases in the course
of time during the ontogenetical process and could be ultimately confined to the most organogenic phase of SAM, from which
shoot characteristics derive. 相似文献
17.
We recently classified 23 bacteria into two types based on their complete genomes; “S-type” as represented by Staphylococcus aureus and “E-type” as represented by Escherichia coli. Classification was characterized by concentrations of Arg, Ala or Lys in the amino acid composition calculated from the
complete genome. Based on these previous classifications, not only prokaryotic but also eukaryotic genome structures were
investigated by amino acid compositions and nucleotide contents. Organisms consisting of 112 bacteria, 15 archaea and 18 eukaryotes
were classified into two major groups by cluster analysis using GC contents at the three codon positions calculated from complete
genomes. The 145 organisms were classified into “AT-type” and “GC-type” represented by high A or T (low G or C) and high G
or C (low A or T) contents, respectively, at every third codon position. Reciprocal changes between G or C and A or T contents
at the third codon position occurred almost synchronously in every codon among the organisms. Correlations between amino acid
concentrations (Ala, Ile and Lys) and the nucleotide contents at the codon position were obtained in both “AT-type” and “GC-type”
organisms, but with different regression coefficients. In certain correlations of amino acid concentrations with GC contents,
eukaryotes, archaea and bacteria showed different behaviors; thus these kingdoms evolved differently. All organisms are basically
classifiable into two groups having characteristic codon patterns; organisms with low GC and high AT contents at the third
codon position and their derivatives, and organisms with an inverse relationship. 相似文献
18.
Kenichi Ohara Momoko Hotta Daisuke Takahashi Takashi Asahida Hitoshi Ida Tetsuya Umino 《Ichthyological Research》2009,56(4):373-379
The genetic diversity and relationship among four morphotypes of Rhinogobius sp. OR, Gobiidae (“Tōshoku,” “Shinjiko,” “Gi-tōshoku,” and “Shimahire”) were investigated with seven microsatellite DNA loci,
and amphidromy of these morphotypes was verified by strontium (Sr) and calcium (Ca) deposition in the otolith. Samples of
“Tōshoku,” “Shinjiko,” “Gi-tōshoku,” and “Shimahire” were collected from, respectively, three, three, two, and four locations
in Japan. Microsatellite analysis detected high genetic diversity (based on the number of alleles, allelic richness, and average
observed heterozygosity) in the “Tōshoku” and “Shinjiko” morphotypes relative to the “Shimahire” morphotype; the “Gi-tōshoku”
morphotype had an intermediate level of variation. Almost all pairwise F
ST values were significantly different from zero (P < 0.001), except between two populations of “Tōshoku.” Clear genetic independence was observed between the “Shinjiko” and
“Shimahire” morphotypes in the Maruyama River. A principle component analysis based on microsatellite data indicated that
the “Tōshoku,” “Shinjiko,” and “Gi-tōshoku” morphotypes were genetically similar. Furthermore, the three populations of “Tōshoku”
were closely related each other, and two of those collected from the Lake Biwa system were a single population. There was,
however, a high degree of genetic differentiation between “Shimahire” and the other morphotypes; moreover, there was high
genetic divergence among four populations of the “Shimahire” morphotype. Amphidromous migratory histories were indicated by
Sr:Ca ratios in two of three populations of the “Shinjiko” morphotype and in one of two “Gi-tōshoku” morphotypes, whereas
all populations of the “Shimahire” morphotype were freshwater residents. The large genetic divergence and low genetic diversity
in “Shimahire” are likely related to migration history. 相似文献
19.
The Macrotermitinae are a large and successful subfamily of fungus-growing termites, characterised by their symbiotic association
with white-rot fungi of the genus Termitomyces. The taxonomy of the subfamily, and in particular of the largest genus Odontotermes, is problematic. We used sequences of the mitochondrial 16S gene from termites occurring in East Africa and Malawi to explore
the phyletic relationships within the genus Odontotermes and to place the genus in the broader context of other fungus-growing termites. We also interpret this phylogeny in relation
to classical morphological taxonomy in the form of absolute and relative dry weights of the sterile castes, and in relation
to innate behaviour as shown by nest architecture and fungus comb structure. This work lays the foundations of a complete
taxonomic revision of the Macrotermitinae.
The phylogeny supports one clear subdivision, here called the “tanganicus” group, within the genus Odontotermes. It also supports the significance of field observations on the structure of fungus combs, as the whole “tanganicus” group
builds fungus combs of the sponge type (or modified forms thereof) which are hardly known elsewhere. Other phyletic relationships
are less clear, the residual sequences being referred to as the “latericius” group. We recognise three probable miniature
species within the “tanganicus” group and another possible one in the residual “latericius group”.
Received 16 January 2007; revised 30 October 2007 and 11 March 2008; accepted 4 April 2008. 相似文献
20.
Scales of lily bulbs are swollen petioles. Lily scale fragments cultured in vitro regenerate bulblets consisting of scales that may or may not carry a leaf blade. The bulblets are dormant and require a cold
treatment to sprout. We added the gaseous plant growth regulator methyl jasmonic acid (MeJA) in the headspace of the tissue-culture
container and studied the effect on plantlet morphology (scale/leaf-blade formation) and dormancy development in three lilies,
Lilium speciosum “Rubrum No. 10,” L. longiflorum “Snow Queen,” and the Asiatic hybrid “Connecticut King.” Methyl jasmonic acid strongly reduced leaf-blade formation in Lilium longiflorum and Connecticut King. This was a specific effect as scale formation was affected much less. The specific inhibition of leaf-blade
formation was not observed in Lilium speciosum. In this lily, high concentrations of methyl jasmonic acid (MeJA) inhibited leaf-blade and scale formation to similar extents.
Methyl jasmonic acid reduced dormancy development in all three lilies, with the largest effect observed in Connecticut King.
In this Asiatic hybrid, almost all bulblets that had regenerated at 300 or 1000 μl l−1 MeJA in the headspace, did not require a dormancy-breaking treatment to achieve sprouting after planting in soil. Previously,
it has been found in lily that treatments that reduce leaf-blade formation promote dormancy development. The present findings
with MeJA do not agree with this. In the three lilies, the various parameters that were studied—regeneration, scale weight,
leaf-blade weight, and dormancy development—were very differently affected by MeJA. 相似文献