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991.
Carmen Fajardo Maria Ludovica Saccà Alicia Gibello María José Martinez-I?igo Mar Nande Carmen Lobo Margarita Martin 《Water, air, and soil pollution》2012,223(6):3385-3392
Fluorescence in situ hybridization (FISH) technique and qPCR analyses, targeting atz genes, were applied to detect the presence of simazine-degrading bacteria in an agricultural soil with a history of herbicide application. atzB-targeted bacteria detected by FISH represented 5% of total soil bacteria with potential capability to metabolize the herbicide. The soil natural attenuation capacity was confirmed in soil microcosms by measuring simazine degradation. Moreover, four bacterial strains were isolated from the soil and identified as Acinetobacter lwoffii, Pseudomonas putida, Rhizobium sp. and Pseudomonas sp. The isolates were able to grow using different s-triazine compounds and related metabolites as the sole carbon source. Growth parameters in presence of simazine were calculated using the Gompertz model. Rhizobium sp. showed the highest simazine degradation (71.2%) and mineralization (38.7%) rates, whereas the lowest values were found to A. lwoffii??50.4% of degradation and 22.4% of mineralization. Results from qPCR analyses of atzA, atzB and atzC genes revealed their presence in Rhizobium sp. and A. lwoffii, being atzB and atzC the most abundant functional genes. Rhizobium sp. showed a higher amount of the three biomarkers compared to A. lwoffii: the atzA, atzB and atzC gene copy number per microlitre were, respectively, 101, 102 and 103-fold higher in the former. Therefore the proposed molecular approaches based on the use of atz genes as biomarkers can be considered as useful tools to evaluate the presence and potential capability of degrading-s-triazines soil microorganisms. 相似文献
992.
Ana Cristina Borba da Cunha Sydney Sabedot Carlos Hoffmann Sampaio Claudete Gindri Ramos Alexandre Rodrigues da Silva 《Water, air, and soil pollution》2012,223(8):4723-4731
The petroleum industry activities provide potential risks to the environment because they can contaminate ecosystems with different organic compounds in the production chain. Several accidents with transport and handling of petroleum and related products occurred in urban areas with harmful effects to the quality of life and economy. In the 1990s, bioremediation and phytoremediation technologies as economically feasible alternatives to repair the environmental damage were developed. In this study, the potential of the willows Salix rubens and Salix triandra were evaluated with regard to the phytoremediation of soils contaminated with petroleum-derived hydrocarbons (total hydrocarbons and polycyclic aromatic hydrocarbons (PAHs)). The PAHs were quantified by extraction from soils and plants using dichloromethane under ultrasonication. The HPLC analysis was performed with GC/MSD equipment. The total hydrocarbons present in uncontaminated soil were quantified by the sum of animal/vegetable oils and greases and mineral oils and greases according to Standard Methods 5520 (1997). The two willows species S. rubens and S. triandra were resistant during the project development. In the contaminated soil, in which both species were planted, the total hydrocarbons concentration was reduced near 98?%. The PAHs content was remarkably reduced as well. Pyrene showed an initial concentration of 23.06???g?kg?1, decreasing in most cases to 0.1???g?kg?1 or to undetectable levels. Chrysene decreased from 126.27???g?kg?1 to undetectable levels. Benzo[k]fluoranthene and benzo[a]pyrene concentrations had also showed a decrease from 28.44 and 3.82???g?kg?1, respectively, to undetectable levels. 相似文献
993.
Chang?Hoon?Lee Sang?Yoon?Kim Maria?B.?Villamil Prabhat?Pramanik Chang?Ok?Hong Pil?Joo?KimEmail author 《Biology and Fertility of Soils》2012,48(4):435-442
Cultivation of green manure plants during the fallow season in rice paddy soil has been strongly recommended to improve soil
properties. However, green manuring may impact greenhouse gas emission, methane (hereafter, CH4) in particular, under the flooded rice cultivation and thus, application of chemical amendments being electron acceptors
can be an effective mitigation strategy to reduce CH4 emissions in irrigated rice (Oryza sativa L.) field amended with green manure. To investigate the effect of iron (Fe) slag silicate fertilizer (hereafter, silicate
fertilizer), which was effective in reducing CH4 emission and increasing rice productivity, in green manure-amended paddy soil, the aboveground biomass of Chinese milk vetch
(hereafter, vetch) was added at rates of 0, 10, 20, and 40 Mg (fresh weight) ha−1 before the application of silicate fertilizer, which was added at rates of 0 and 2.3 Mg ha−1. Silicate fertilization reduced the seasonal CH4 flux by ca. 14.5% and increased rice yield by ca. 15.7% in the control (no vetch application) treatment. However, CH4 production was increased by silicate fertilization in vetch-treated soil particularly at the initial rice growing stage,
which was probably due to the enhanced decomposition of added organic matters by the silicate liming effect. In conclusion,
silicate fertilization is not effective in reducing CH4 production in green manure-amended rice paddy soils and its use should be properly controlled. 相似文献
994.
Maria João Verdasca Ana Sofia Leitão Joana Santana Miguel Porto Susana Dias Pedro Beja 《Biological conservation》2012,146(1):14-23
In cultural landscapes there are often negative biodiversity consequences of agricultural abandonment and subsequent scrub and forest encroachment, due to homogenization and the loss of early-successional habitats. The common forestry practice of removing understory vegetation to prevent fire hazard (fuel management) probably has the side-effect of ameliorating these consequences, but it is uncertain whether it effectively restores habitats for early-successional species. Here we examine the influence of time since fuel management and management frequency on butterfly assemblages, using a chronosequence of cork oak (Quercus suber) stands spanning about 70 years. Overall species richness increased immediately after management and abundances peaked about 2–3 years later, while both declined thereafter for about 10–20 years to pre-disturbance levels. Richness and abundances were also much higher in recurrently managed stands. Most life history groups showed successional trends similar to the overall species richness and abundances, though consistent positive effects of fuel management were only observed for species with univoltine life cycle, herbaceous layer feeding, larval overwintering, and intermediate body size. Individual species were largely associated with recent and recurrent management, though a few specialists occurred most often in undisturbed stands. These findings suggest that fuel management at <10 years intervals is strongly positive for butterfly assemblages in landscapes under land abandonment. However, to maintain the overall forest biodiversity it is critical that patches of undisturbed habitat are also retained at the landscape scale. 相似文献
995.
996.
Summary The narrow genetic base of the cultivated potato is a severe constraint for potato breeding. Wild tuber-bearing species constitute
an important source of genes for resistance to diseases and pests as well as abiotic factors. Seven interspecific hybrid populations
were generated from crosses between diploidTuberosum clones and four wild species:Solanum berthaultii, S. gourlayi, S. tarijense andS. vernei, and evaluated in a field experiment in Burgos (Spain) as a way to broaden the genetic base of the cultivated potato. Good
tuberization ability and great variability for yield within the different families were detected. Hybridization with the wild
species resulted in high levels of PVY resistance inS. berthaultii andS. vernei hybrids and a large increase of dry matter content in all populations except theS. berthaultii hybrids. 相似文献
997.
Pilar?Cano Vanessa?Jiménez Maria?P?álvarez Mario?Alvari?o Daniel?P?Cardinali Ana?I?EsquifinoEmail author 《Journal of circadian rhythms》2005,3(1):9
Background
This work describes the effect of a 48-h litter separation on 24-h patterns of plasma prolactin, FSH and LH concentration in female lactating rabbits kept under a 16:8 light-dark photoperiod (lights on at 0800 h). 相似文献998.
Esquifino AI Chacón F Jimenez V Reyes Toso CF Cardinali DP 《Journal of circadian rhythms》2004,2(1):1
BACKGROUND: This work analyzes the effect of social isolation (a mild stressor) on the 24-h variation of pituitary-testicular function in young Wistar rats, assessed by measuring circulating levels of prolactin, FSH, LH and testosterone. METHODS: Animals were either individually caged or kept in groups (4-5 animals per cage) under a 12:12 h light-dark cycle (lights on at 0800 h) for 30 days starting on day 35 of life. Rats were killed at 4-h intervals during a 24-h cycle, beginning at 0900 h. RESULTS: Isolation brought about a decrease in prolactin, LH and testosterone secretion and an increase of FSH secretion. In isolated rats the 24-h secretory pattern of prolactin and testosterone became modified, i.e., the maximum in prolactin seen in control animals at the beginning of the activity span was no longer detected, whereas the maximum in circulating testosterone taking place at 1700 h in controls was phase-delayed to 2100 h in isolated rats. CONCLUSION: Social isolation affects the 24-h variation of pituitary-testicular function in young rats. Secretion of prolactin, LH and testosterone decreases, and secretion of FSH increases, in isolated rats. The maximum in prolactin seen in group-caged rats at the beginning of the activity span is not observed in isolated rats. The maximum in circulating testosterone taking place at the second part of the rest span in controls is phase-delayed to the light-dark transition in isolated rats. 相似文献
999.
Anunciación Lafuente Teresa Cabaleiro Pilar Cano Ana I Esquifino 《Journal of circadian rhythms》2006,4(1):3-9
Background
This work addresses the issue of whether methoxychlor (MTX) exposure may modify the ultradian secretion of prolactin through changes in the synthesis of nitric oxide (NO) induced by Nω-nitro-L-arginine methyl ester (L-NAME) in the hypothalamic-pituitary axis. Associated changes in dopamine (DA) content in the anterior (AH), mediobasal (MBH) and posterior hypothalamus (PH) and median eminence (ME) were evaluated. 相似文献1000.
Jaine H. H. L. de Oliveira Mirna H. R. Seleghim Christoph Timm Achim Grube Matthias K?ck Gislene G.F. Nascimento Ana Claudia T. Martins Elissa G. O. Silva Ana Olívia de Souza Paulo R. R. Minarini Fabio C. S. Galetti Célio L. Silva Eduardo Hajdu Roberto G. S. Berlinck 《Marine drugs》2006,4(1):1-8
Cyclostellettamines A – F (1 – 6) isolated from the sponge Pachychalina sp. and cyclostellettamines G - I, K and L (7 – 11) obtained by synthesis were evaluated in bioassays of antimicrobial activity against susceptible and antibiotic-resistant Staphylococcus aureus, Pseudomonas aeruginosa and antibiotic-susceptible Escherichia coli and Candida albicans, as well as in antimycobacterial activity against Mycobacterium tuberculosis H37Rv bioassays. The results obtained indicated that cyclostellettamines display different antimicrobial activity depending on the alkyl-chain size, suggesting that, if a mechanism-of action is implied, it is dependent on the distance between the two pyridinium moieties of cyclostellettamines. 相似文献