The degradation of uniformly14C-labelled dibenzofuran (DBF) by the strainPseudomonas sp HH 69 and a consortium consisting of the DBF-degrading Pseudomonas strain NRM and an accompanying Nocardia-like strain NRH, was monitored in liquid-batch cultures and in different soil samples. Experiments involving the strain and a consortium in aereated liquid cultures (batch process) showed that DBF was utilized as a source of energy and carbon. Thereby, more than 65% of DBF is rapidly converted to CO2, about 20% to biomass and only about 10% to slow-degrading intermediate metabolites, respectively. The same microorganisms also exhibited comparable degrees of degradation efficiency in various types of soils contaminated with DBF. For instance, DBF, uniformly distributed in sterile soil samples, in concentrations between 0.2 to 200 ppm, was converted to CO2, within 10 days, to the extent of about 75% by the strainPseudomonas sp. HH 69. 相似文献
In this paper, the effect of pH on biological degradation of Microcystis aeruginosa by alga-lysing bacteria in laboratory-scale sequencing batch biofilm reactors (SBBRs) was investigated. After 10 d filming with waste activated sludge, the biological film could be formed, and the bioreactors in which laid polyolefin resin filler were used to treat algal culture. By comparing the removal efficiency of chlorophyll a at different aerobic time, the optimum time was determined as 5 h. Under pH 6.5, 7.5, and 8.5 conditions, the removal rates of Microcystis aeruginosa were respectively 75.9%, 83.6%, and 78.3% (in term of chlorophyll a), and that of Chemical Oxygen Demand (CODMn) were 30.6%, 35.8%, and 33.5%. While the removal efficiencies of ammonia nitrogen (NH4+ - N) were all 100%. It was observed that the sequence of the removal efficiencies of algae, NH4+ - N and organic matter were pH 7.5>pH 8.5>pH 6.5. The results showed that the dominant alga-lysing bacteria in the SBBRs was strain HM-01, which was identified as Bacillus sp. by Polymerase Chain Reaction (PCR) amplification of the 16S rRNA gene, Basic Local Alignment Search Tool (BLAST) analysis, and comparison with sequences in the GenBank nucleotide database. The algicidal activated substance which HM-01 strain excreted could withstand high temperature and pressure, also had better hydrophily and stronger polarity. 相似文献
Gonadal sex steroid hormones are the principal factors that directly control the gonadal and morphological alterations during
sex change in hermaphrodite fish; however, the physiological mechanism of action by which these hormones govern body coloration
is poorly understood. The protogynous wrasse Pseudolabrus sieboldi is a good model for understanding the physiological mechanisms of gonadal and body color change during sex change in hermaphrodite
fish. To obtain information on the relationship between sex steroids and body color change during the process of gonadal sex
change, we analyzed body color, gonadal histology, and serum levels of sex steroids. Body color was analyzed using a quantitative
analytical method based on the hue value. Compared to other body parts of the fish, the anal fin changed color the most, becoming
increasingly redder in association with gonadal changes that converted ovaries to testes. Levels of serum 11-ketotestosterone
(11KT) increased as the gonadal sex change proceeded, whereas no significant change was observed in estradiol-17β (E2) levels.
Moreover, we found a significant correlation between the hue value of the anal fin and serum 11KT levels, but not E2 levels.
These results suggest that androgen, but not estrogen, plays a principle role in the changes in both gonadal morphology and
body color in the transformation from female to male in this species. To our knowledge, this is the first quantitative demonstration
of the relationship between body color and serum steroid levels during sex change in fish. 相似文献
•Steroid hormones could be removed efficiently from mariculture system using seaweed;• Caulerpa lentillifera was the most efficient seaweed for removal of steroid hormones;• More than 90% of E2 or EE2 were removed within 12 h using Caulerpa lentillifera;• The removal included the rapid biosorption and the slow bio-accumulation;•The hormones and nutrients in mariculture wastewater could be simultaneously removed. The removal of steroid hormones from the mariculture system using seaweeds (Caulerpa lentillifera, Ulva pertusa, Gracilaria lemaneiformis, and Codium fragile) was investigated. The results illustrated that both 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) could be removed by the seaweeds at different levels, and the Caulerpa lentillifera was the most efficient one. More than 90% of E2 or EE2 at concentration of 10 μg/L was removed by Caulerpa lentillifera within 12 h. Processes including initial quick biosorption, the following slow accumulation, and biodegradation might explain the removal mechanisms of E2/EE2 by Caulerpa lentillifera. E2/EE2 removal was positively related to the nutrient level and the initial concentration of steroid hormone. A significant linear relationship for E2 and EE2 existed between the initial pollutant concentration and the average removal rate. The highest removal kinetic constant (k) value was obtained at 30°C as 0.34 /h for E2 and at 20°C as 0.28 /h for EE2, demonstrating the promising application potential of Caulerpa lentillifera in the water purification of the industrialized mariculture system with relatively high water temperature. Simultaneous and efficient removal of E2 and EE2 by Caulerpa lentillifera was still achieved after 3 cycles in the pilot-scale experiment. The steroid hormones and nutrients in mariculture wastewater could also be simultaneously removed using Caulerpa lentillifera. These findings demonstrated that Caulerpa lentillifera was the promising seaweed for the removal of steroid hormones in mariculture systems. 相似文献
• A. sydowii strain bpo1 exhibited 99.8% anthracene degradation efficiency.• Four unique metabolic products were obtained after anthracene degradation.• Ligninolytic enzymes induction played vital roles in the removal of anthracene.• Laccase played a crucial role in comparison with other enzymes induced. The present study investigated the efficiency of Aspergillus sydowii strain bpo1 (GenBank Accession Number: MK373021) in the removal of anthracene (100 mg/L). Optimal degradation efficiency (98.7%) was observed at neutral pH, temperature (30℃), biomass weight (2 g) and salinity (0.2% w/v) within 72 h. The enzyme analyses revealed 131%, 107%, and 89% induction in laccase, lignin peroxidase, and manganese peroxidase respectively during anthracene degradation. Furthermore, the degradation efficiency (99.8%) and enzyme induction were significantly enhanced with the addition of 100 mg/L of citric acid and glucose to the culture. At varying anthracene concentrations (100–500 mg/L), the degradation rate constants (k1) peaked with increasing concentration of anthracene while the half-life (t1/2) decreases with increase in anthracene concentration. Goodness of fit (R2 = 0.976 and 0.982) was observed when the experimental data were subjected to Langmuir and Temkin models respectively which affirmed the monolayer and heterogeneous nature exhibited by A. sydwoii cells during degradation. Four distinct metabolites; anthracene-1,8,9 (2H,8aH,9aH)-trione, 2,4a-dihydronaphthalene-1,5-dione, 1,3,3a,7a-tetrahydro-2-benzofuran-4,7-dione and 2-hydroxybenzoic acid was obtained through Gas Chromatography-Mass spectrometry (GC-MS). A. sydowii exhibited promising potentials in the removal of PAHs. 相似文献
Petroleum hydrocarbons, mainly consisting of n-alkanes and polycyclic aromatic hydrocarbons (PAHs), are considered as priority pollutants and biohazards in the environment, eventually affecting the ecosystem and human health. Though many previous studies have investigated the change of bacterial community and alkane degraders during the degradation of petroleum hydrocarbons, there is still lack of understanding on the impacts of soil alkane contamination level. In the present study, microcosms with different n-alkane contamination (1%, 3% and 5%) were set up and our results indicated a complete alkane degradation after 30 and 50 days in 1%- and 3%-alkane treatments, respectively. In all the treatments, alkanes with medium-chain length (C11-C14) were preferentially degraded by soil microbes, followed by C27-alkane in 3% and 5% treatments. Alkane contamination level slightly altered soil bacterial community, and the main change was the presence and abundance of dominant alkane degraders. Thermogemmatisporaceae, Gemmataceae and Thermodesulfovibrionaceae were highly related to the degradation of C14- and C27-alkanes in 5% treatment, but linked to alkanes with medium-chain (C11-C18) in 1% treatment and C21-alkane in 3% treatment, respectively. Additionally, we compared the abundance of three alkane-monooxygenase genes, e.g., alk_A, alk_P and alk_R. The abundance of alk_R gene was highest in soils, and alk_P gene was more correlated with alkane degradation efficiency, especially in 5% treatment. Our results suggested that alkane contamination level showed non-negligible effects on soil bacterial communities to some extents, and particularly shaped alkane degraders and degrading genes significantly. This study provides a better understanding on the response of alkane degraders and bacterial communities to soil alkane concentrations, which affects their biodegradation process.
The defining feature of the life cycle in monogonont rotifers such as Brachionus plicatilis (Muller) is alternation of asexual and sexual reproduction (mixis). Why sex is maintained in such life cycles is an important unsolved evolutionary question and one especially amenable to experimental analysis. Mixis is induced by a chemical signal produced by the rotifers which accumulates to threshold levels at high population densities. The chemical features of this signal were characterized using size exclusion, enzymatic degradation, protease protection assays, selective binding to anion ion exchange and C3 reversed phase HPLC columns, and the sequence of 17 N-terminal amino acids. These studies were carried out over two years beginning in 2003 using B. plicatilis Russian strain. When rotifer-conditioned medium was treated with proteinase K, its mixis-inducing ability was reduced by 70%. Proteinase K was added to medium auto-conditioned by 1 female ml−1 where typically 17% of daughters became mictic and mixis was reduced to 1%. A cocktail of protease inhibitors added to conditioned medium significantly reduced degradation of the mixis signal by natural proteases. Conditioned medium subjected to ultrafiltration retained mixis-inducing activity in the >10 kDa fraction, but the <10 kDa fraction had no significant activity. The putative mixis signal bound to an anion exchange column, eluting off at 0.72 M NaCl. These fractions were further separated on a C3 reversed phase HPLC column and mixis-inducing activity was associated with a 39 kDa protein. Seventeen amino acids from the N-terminus have strong similarity to a steroidogenesis-inducing protein isolated from human ovarian follicular fluid. The 39 kDa protein is an excellent candidate for the rotifer mixis induction signal. 相似文献
In recent years, Conogethes pluto (Lepidoptera: Crambidae) has become a major pest of Alpinia and other ornamental gingers in the Northern Territory and Queensland, Australia. This pest damages the flowers and bores into the stems, causing substantial losses to production. Currently, no synthetic sex pheromone is available to monitor or control this pest. This work aims at the identification of the sex pheromone of this pest. Analysis of the sex pheromone gland of female C. pluto by gas chromatography/electroantennogram detector revealed the presence of seven candidate pheromone compounds that elicited electroantennogram responses. Using gas chromatography/mass spectrometry analysis and micro-derivatization reactions, six compounds were identified as (E)-10-hexadecenal, as the main pheromone compound, (Z)-10-hexadecenal, hexadecanal, (E)-10-hexadecen-1-ol, (10E,12E)-hexadeca-10,12-dienal and (3Z,6Z,9Z)-tricosa-3,6,9-triene as minor pheromone compounds. In two-field trapping experiments, C. pluto responded to the six-component blend, and three of six compounds, i.e., (E)-10-hexadecenal, (3Z,6Z,9Z)-tricosa-3,6,9-triene, and (10E,12E)-hexadeca-10,12-dienal were shown to be necessary for attraction. In a subsequent experiment testing various doses (i.e., 0.01, 0.1, and 1 mg) of the six-component blend, the largest number of males was captured in traps baited with a lure loading of 1 mg. The availability of the sex pheromone of C. pluto will enable monitoring and provides the basis for additional control options for this pest. 相似文献
The aim of this study was to identify genes involved in long-chain alkane degradation in Dietzia sp. DQ12-45-1b. Functional genes were annotated by genome analysis. Induction of alkane hydroxylase genes by C28 n-alkane was analyzed by using quantitative real-time PCR in wild-type Dietzia sp. DQ12-45-1b and its alkW1 gene knockout mutant strain M 5-5. From the genome of Dietzia sp. DQ12-45-1b, two homologues, G1 and G2 genes were annotated, which showed 50% amino acid sequence similarity with AlmA from Acinetobacter sp. DSM17874, and 48% amino acid sequence similarity with LadA from Geobacillus thermodenitrificans NG80-2, respectively. In addition, G1 showed 71% amino acid sequence similarity with G1a, and G2 showed 34% and 87% amino acid sequence similarities with G2a and G2ß, respectively, which were annotated from Dietzia sp. E1 genome. In addition, the alkW1 gene knockout strain M 5-5 could grow with C28 n-alkane as the sole carbon source, indicating the presence of potential long-chain alkane hydroxylase gene(s) other than alkW1 in Diezia sp. DQ12-45-1b. Accordingly, induction of G1 and G2 genes was observed when Dietzia ap. DQ12-45-1b and alkW1 knockout mutant strain M 5-5 grew with C28 n-alkane as sole carbon source. The results indicated that G1 and G2 genes are mostly responsible for the degradation of long-chain alkanes in Dietzia sp. DQ12-45-1b, which has unique multiple alkane hydroxylase systems. 相似文献
Ibuprofen (IBU) is widely used in the world as anti-inflammatory drug, which posed health risk to the environment. A bacterium capable of degrading IBU was isolated from activated sludge in a sewage treatment plant. According to its morphological, physiologic, and biochemical characteristics, as well as 16S rRNA sequence analysis, the strain was identified as Serratia marcescens BL1 (BL1). Degradation of IBU required the presence of primary substrate. After a five-day cultivation with yeast powder at 30°C and pH 7, the highest degradation (93.47%±2.37%) was achieved. The process of BL1 degrading IBU followed first-order reaction kinetics. The BL1 strain was applied to a small biological aerated filter (BAF) device to form a biofilm with activated sludge. IBU removal by the BAF was consistent with the results of static tests. The removal of IBU was 32.01% to 44.04% higher than for a BAF without BL1. The indigenous bacterial community was able to effectively remove CODMn (permanganate index) and ammonia nitrogen in the presence of BL1.
Summary. To gain insight into the evolution of the sex pheromone communication system in Ostrinia (Lepidoptera Pyralidae), the sex pheromone of the burdock borer, O. zealis was analyzed by means of gas chromatography-electroantennographic detection (GC-EAD), GC-mass spectrometry and a series of
bioassays. Four EAD-active compounds were detected in the female sex pheromone gland extract, and these were identified as
tetradecyl acetate (14:OAc), (Z)-9-tetradecenyl acetate (Z9–14:OAc), (E)-11-tetradecenyl acetate (E11-14:OAc) and (Z)-11-tetradecenyl acetate (Z11-14:OAc). The average amounts (ratio) of the four compounds in single sex pheromone glands were 2.5 ng (13%), 11.6 ng (61%),
4.1 ng (21%) and 0.9 ng (5%), respectively. In a wind-tunnel bioassay, the ternary blend of Z9-, E11- and Z11-14:OAc at a ratio found in the sex pheromone gland elicited the same behavioral responses from the males as did virgin
females. 14:OAc did not show any enhancement or inhibition of the males’ behavioral responses when added to the ternary blend.
The attractiveness of the 3-component lure to O. zealis males was also confirmed by field trapping experiments. Based on these results, we concluded that the sex pheromone of O. zealis is composed of Z9-14:OAc, E11-14:OAc and Z11-14:OAc at a ratio of 70:24:6. The evolutionary changes of the sex pheromones in Ostrinia are also discussed based on the presently available information on the sex pheromones and phylogenetic relationships of Ostrinia spp.
Received 25 September 1998; accepted 2 December 1998. 相似文献
Early androgen exposure is known to have long-lasting effects on phenotype, behaviour and even fitness, but difficulties in
measuring the exposure hinders the study of its importance in evolutionary context. Digit ratios have been highlighted as
a potential easy-to-measure indicator of early steroid exposure, as they have been suggested to reflect steroid, mainly testosterone
levels during prenatal development. However, evidence for digit ratios reflecting early steroid levels is weak, as experimental
studies, especially in wild populations, are scarce. We studied the association between maternally derived yolk androgens
and digit ratios (2D:4D, 2D:3D and 3D:4D) using both correlative data and a rather high level of experimental elevation of
yolk androgens in a passerine bird, the pied flycatcher (Ficedula hypoleuca). We also examined whether digit ratios have indicator value in an evolutionary context by studying correlations between
digit ratios and reproductive traits, secondary sexual traits and exploratory behaviour. We did not find any association between
digit ratios and yolk androgen level either in correlative or experimental data. Digit ratios were neither related to any
of the reproductive and secondary sexual traits or exploratory behaviour measured. There was, however, a sex difference in
2D:3D and 3D:4D of adult birds (due to second and fourth digits being shorter in females), which was not apparent in fledglings
or captivity-raised juveniles. This suggests that either the sex difference may develop as late as during the sexual maturation
for breeding. These results indicate that, in this species, digit ratios are not reliable markers of maternally derived yolk
androgen exposure and that they bear little relevance as correlates of the adaptive traits we measured. 相似文献