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1.
Nitration of pyridoindoles (β‐carbolines) was carried out using different nitration methods and structural assignments of these nitro compounds were made using different spectroscopic techniques. The mutagenic activity of these nitro derivatives was studied using Salmonella typhimurium strains TA 98 NR and TA 100 NR in the absence as well as in the presence of S‐9 mix. Only trinitro derivatives were found to be highly mutagenic to strain TA 98 NR.  相似文献   

2.
Two different copolyesters, aliphatic poly(butylene succinate-co-dilinoleate) and aliphatic-aromatic poly(ethylene succinate-co-terephthalate), were used in the preparation of controlled-release fertilizers (CRFs). The properties of the resulting polymer-coated materials were examined via scanning electron microscopy and strength testing machinery, whereas nutrient release was measured in water and soil with the use of photometric method. Both polymer-coated materials meet the criteria of CRFs when their polymer content is higher than 18 wt %. Differences in the results of the experiments performed in soil and water were explained by the discrepancies in the structure and composition of both copolymers and their degradation tendencies. Both polymer-coated materials were proven to be more resistant toward crushing strength than the initial fertilizer. For interpretation of the experimental kinetic data, a sigmoidal equation was successfully applied.  相似文献   

3.
Environmental Geochemistry and Health - The importance of environmental geochemistry baseline in soils of O´Higgins Region, Chile, since it hosts in its eastern area one of the major Cu-Mo...  相似文献   

4.
Eusociality in mammals is defined in the present paper by the following criteria: reproductive altruism (which involves reproductive division of labor and cooperative alloparental brood care), overlap of adult generations, and permanent (lifelong) philopatry. We argue that additional criteria such as the existence of castes, colony size, reproductive skew, and social cohesion are not pertinent to the definition of eusociality in mammals. According to our definition of mammalian eusociality, several rodent species of the African family Bathyergidae can be considered eusocial, including the naked mole-rat (Heterocephalus glaber), Damaraland mole-rat (Cryptomys damarensis), and several additional, if not all, species in the genus Cryptomys. Furthermore, some species of social voles (like Microtus ochrogaster) may also fulfill criteria of mammalian eusociality. Understanding the evolution of eusociality in mole-rats requires answers to two primary questions: (1) What are the preconditions for the development of their eusocial systems? (2) Why do offspring remain in the natal group rather than dispersing and reproducing? Eusociality in mammals is by definition a special case of monogamy (more specifically: monogyny one female breeding), involving prolonged pair bonding for more than one breeding period. We argue that eusociality in mole-rats evolved from a monogamous mating system where cooperative brood care was already established. A tendency for group living is considered to be an ancestral (plesiomorph) trait among African bathyergid mole-rats, linking them to other hystricognath rodents. A solitary lifestyle seen in some genera, such as Bathyergus, Georychus, and Heliophobius, is assumed to be a derived trait that arose independently in different lineages of bathyergids, possibly as a consequence of selective constraints associated with the subterranean environment. In proximate terms, in eusocial mole-rats either puberty is assumed to be developmentally delayed so that under natural conditions most animals die before dispersal is triggered (e.g., in the case of Heterocephalus) or dispersal is induced only by an incidental encounter with an unfamiliar, yet adequate sexual partner (e.g., in the case of Cryptomys). Ultimately, a combination of strategies involving either dispersal and/or philopatry can be beneficial, especially in a highly unpredictable environment. If genetic relatedness among siblings is high (e.g., a coefficient of relatedness of 0.5 or more), then philopatry would not invoke an appreciable loss of fitness, especially if the cost of dispersing is higher than staying within the natal group. High genetic relatedness is more likely in a monogamous mating system or a highly inbred population. In this paper, we argue that the preconditions for eusociality in bathyergid mole-rats were a monogamous mating system and high genetic relatedness among individuals. We argue against the aridity food-distribution hypothesis (AFDH) that suggests a causal relationship between cooperative foraging for patchily distributed resources and the origin of eusociality. The AFDH may explain group size dynamics of social mole-rats as a function of the distribution and availability of resources but it is inadequate to explain the formation of eusocial societies of mole-rats, especially with respect to providing preconditions conducive for the emergence of eusociality.  相似文献   

5.
The purpose of this study is to evaluate opportunities of the region of Su?la Lake located in Turkey for community-based ecotourism development that enable sustainable landscape and natural resource management as well as livelihood diversification. A participatory research approach was applied by participation of a diverse number of stakeholders (e.g. local communities, local and central governmental bodies and researchers). A set of participatory research tools (e.g. interviews and field surveys), SWOT analysis and the method of Ecotourism Opportunity Spectrum (ECOS) were used to collect and evaluate relevant data. The study consists of four sections. The first section focuses on SWOT analysis by which the advantages and disadvantages of the study area for ecotourism development were examined. In the second section, the most suitable villages for ecotourism development were examined by adapting the method of ECOS based on the 18 parameters by using 1–4 score system. Accordingly, the most suitable five villages for ecotourism development were determined. Major natural and cultural ecotourism resources (e.g. diversity of landforms, spectacular landscapes and traditional lifestyle) of the study area were examined in the third section. In the fourth section, the ecotourism-based livelihood and relevant core capitals were evaluated according to 1–4 score system for the five villages. We hope that the outcomes of this study can draw attention of planners and policymakers to the role of ecotourism for sustainable landscape and natural resource management as well as livelihood diversification in the region and elsewhere.  相似文献   

6.
The interaction of HCH (50 mg/kg) and dietary protein levels on microsomal drug metabolizing enzymes system and liver lipids were studied in the rats for 90 days. The results indicated that rats fed a lower protein diet and HCH has a higher rate of mortality, lower rate of growth and an increased liver weight. A significant induction in the hepatic microsomal aminopyrine‐N‐demethylase, p‐nitroanisole‐O‐dealkylase, benzo(a)pyrene hydroxylase and glutathione‐S‐transferase activity was observed in pesticide treated animals as compared to control animals. The pathological changes observed in liver of HCH treated animals consisted mainly of necrosis and fatty degeneration of hepatocytes. HCH also induced the significant accumulation of cholesterol, triglycerides, phospholipid and total lipid in liver in low protein diet animals. Protein accelerates the metabolism of HCH, resulting in a decrease of HCH concentration with the increase of dietary protein level. A close correlation existed between lipid accumulation, induction of drug metabolizing enzyme system and deposition of HCH in liver.  相似文献   

7.
Summary. Qualitative and quantitative differences among pear cultivars were found in constitutive and Cacopsylla-induced volatiles, depending on experimental treatment of the trees (i.e., uninfested and partly or completely infested by psyllids). Blend differences were also found between pear cultivars and wild-type pear, alder and hawthorn–the latter trees are frequently present in pear orchard hedgerows. ?Interesting differences were found in the presence of methyl salicylate and (E,E)-α-farnesene, two compounds previously found to mediate attraction of predatory bugs towards psyllid-infested pear trees. Methyl salicylate is expressed constitutively and is induced systemically by infestation in the whole plant of all four cultivars. (E,E)-α-farnesene on the other hand showed also systemic induction in Bartlett, NY10355 and Beurré Hardy, but in partially infested Conference trees it was induced locally, only in herbivore-damaged leaves. No methyl salicylate or (E,E)-α-farnesene were identified in honeydew. In field collected headspace samples of alder leaves infested by aphids and leaf beetles we found methyl salicylate but no (E,E)-α-farnesene, whereas in uninfested hawthorn neither were identified. Insight in the variability of damage-related pear volatiles will have important implications for integrated pest management in the field. Received 27 August 2002; accepted 28 November 2002 R1D=" Correspondence to: Petru Scutareanu, e-mail:scuterea@science.uva.nl  相似文献   

8.
In this study, autopsy tissue samples from human liver and kidneys were analysed for Cd, Cu, Pb, Zn, Hg and Mn in 25 subjects (16 males and 9 females) ranging in age from 2 to 70 years. Tissue samples that were pathologically normal were obtained at postmortem and concentrations of metals were determined. In both kidneys and liver, the concentrations of metals followed the order Cd > Hg > Pb > Zn > Mn > Cu irrespective of gender and age group, except in female kidneys where the order was Cd > Pb > Hg > Zn > Mn > Cu. Generally, males had higher concentrations of metals in both the kidneys and liver. Significant correlations of the metals were found in kidney and liver tissues.  相似文献   

9.
糖外排转运蛋白(sugars will eventually be exported transporters,SWEET)介导植物光合同化产物蔗糖的跨膜运输.以橄榄(Canarium album(Lour.)Raeusch.)果实为材料,通过气相色谱串联质谱(GC-MS)检测橄榄果实中糖组分及含量变化,利用RT-PCR技术克隆得到CaSWEET7和CaSWEET15基因开放阅读框(ORF)序列.结果表明:CaSWEET7和CaSWEET15基因ORF全长分别为774 bp和951 bp,分别编码长度为257个和316个氨基酸残基,具有2个MtN3_slv结构域;进化树分析表明,CaSWEET7属于CladeⅡ,CaSWEET15属于CladeⅢ.实时荧光定量PCR(qRT-PCR)技术检测其在不同发育时期的果实中相对表达量变化,结果表明,随着果实发育,CaSWEET7和CaSWEET15表达量逐渐递增,且与果实发育蔗糖含量变化呈显著正相关(相关性系数分别为0.931和0.904,P<0.05);利用酵母功能互补证明CaSWEET7和CaSWEET15基因编码的蛋白具有转运蔗糖能力.本研究表明CaSWEET7和CaSWEET15基因可能在橄榄果实蔗糖积累中发挥作用.(图9表2参44)  相似文献   

10.
Whether migrating birds compensate for wind drift or not has been discussed frequently during the last decades. Observed behaviours seem to differ between species and situations. Even though complete compensation allows a bird to fly the shortest distance during its migration, this is not necessarily the optimal solution in all cases. There are certain situations when drifting with the wind, and thus getting higher groundspeed, will be more beneficial, i.e. adaptive drift. In this article, I analyse flight directions of spring migrating barnacle and brent geese, tracked by radar and optical range finder, and compare these with prevailing winds to see if these birds compensate or drift with the wind. I also use wind data from the days when the trackings were made to construct expected flight paths to see whether wind drift or compensation would be the most beneficial behaviour. The geese were found to drift partially with the wind. The drift effect was concluded to be true partial drift, i.e. not pseudodrift or drift forced by strong winds. The drift was not found to be of any obvious adaptive value, as the geese drifted irrespective of the strategy that would have been most beneficial to them. None of the situations in which drift is predicted to be adaptive was applicable to the birds and migration days in this study. A possible explanation for the observed pattern is that since these birds usually have access to favourable winds during their spring migration, selection pressures for adaptive drift or compensation behaviours might be weak.  相似文献   

11.
The flow structure in the aerated region of the roller generated by breaking waves remains a great challenge to study, with large quantities of entrained air and turbulence interactions making it very difficult to investigate in details. A number of analogies were proposed between breaking waves in deep or shallow water, tidal bores and hydraulic jumps. Many numerical models used to simulate waves in the surf zone do not implicitly simulate the breaking process of the waves, but are required to parameterise the wave-breaking effects, thus relying on experimental data. Analogies are also assumed to quantify the roller dynamics and the energy dissipation. The scope of this paper is to review the different analogies proposed in the literature and to discuss current practices. A thorough survey is offered and a discussion is developed an aimed at improving the use of possible breaking proxies. The most recent data are revisited and scrutinised for the use of most advanced numerical models to educe the surf zone hydrodynamics. In particular, the roller dynamics and geometrical characteristics are discussed. An open discussion is proposed to explore the actual practices and propose perspectives based on the most appropriate analogy, namely the tidal bore.  相似文献   

12.
Some ecotoxic metals such as Cd, Pb, and Cu in Tessaria absinthioides were quantified to study its possible use as a bio‐indicator and/or bio‐monitor of these metals. This plant was chosen for its abundance in the area under study, along Chile and even in southern Latin America. For Cd, Pb, and Cu in all three parts of the plant (leaves, stems and roots) a different concentration pattern in each sampling areas was observed. In sampling areas Coya Sur and La Cascada copper and cadmium concentration decrease in order: leaves > roots > stems. In samples collected in Xalquincha the lowest concentrations of Cd and Pb were observed in stems. A maximum of cadmium concentration (9ug/gd.w. in leaves) was found in samples from La Cascada, a inflow to river Loa in Calama. High concentrations of lead were found in roots and leaves. Collected data demonstrate that the main pathway for cadmium is from ground water via roots into the plant. Some data obtained for lead and copper indicate that the influence of dust particles adsorbed on leaves and stems can be higher than uptake from ground water.  相似文献   

13.
This investigation was carried out to determine the hydrogeochemical characteristics of the Kirkgeçit and Ozancik hot springs. The study areas are located northeast and southwest of the town of Çan, Çanakkale. During the investigation, geological maps of the hot springs and its surroundings were prepared, and hot waters and rock samples were collected from the study sites. The Paleogene–Neogene aged andesite, trachyandesite, andesitic tuff, silicified tuff and tuffites form the basement rocks in the Ozancik hot spring area. In the Kirkgeçit hot spring area, there are Lower Triassic aged mica and quartz schists at the basement rocks. The unit is covered by limestones and marbles of the same age. They are overlain by Quaternary alluvial deposits. A chemical analysis of the Kirkgeçit hot water indicates that it is rich in SO4 2– (1200.2 mg L–1), Cl (121.7 mg L–1), HCO3 (32.5 mg L–1), Na+ (494 mg L–1), K+ (30.2 mg L–1), Ca2+ (102 mg L–1), Mg2+ (15.2 mg L–1), and SiO2 (65.22 mg L–1). Chemical analysis of the Ozancik hot water indicates that it is rich in SO4 2– (575 mg L–1), Cl (193.2 mg L–1), HCO3 (98.5 mg L–1), Na+ (315 mg L–1), K+(7.248 mg L–1), Ca2+ (103 mg L–1), Mg2+ (0.274 mg L–1), and SiO2(43.20 mg L–1). The distribution of ions in the hot waters on the Schoeller diagram has an arrangement of r(Na++K+)>rCa2+>rMg2+ and r(SO4 2–)>rCl>r(HCO3 ). In addition, the inclusion of Fe2+, Cu2+, Cr3+, Mn2+, Ni2+ and Hg2+ in the hot water samples indicates potential natural inorganic contamination. The water analysis carried out following the ICPMS-200 technique was evaluated according to the World Health Organisation and Turkish Standards. The use and the effects of the hot water on human health are also discussed in the paper.  相似文献   

14.
Anaerobic ammonium oxidation (Anammox) is a biological process that has the advantages of saving energy and being highly efficient. However, there are some problems with it such as slow proliferation and activity inhibition of Anammox bacteria in practical applications. First, we introduce the inhibitory effects of Anammox by substrate and non-substrate materials, including nitrite, organic and inorganic substances, and others, and elaborated on activity recovery approaches such as controlling the operation parameters and adding sludge. The effects of the addition of inorganic carbon, Anammox intermediates, Fe, and conductive materials on Anammox are then reviewed in detail, and three Anammox metabolic pathways are summarized. Finally, we discuss the problems (including NOB inhibition and low temperature) and countermeasures when Anammox is applied for wastewater treatment as a mainstream technology, and we summarized the measures of NOB washout by free ammonia and free nitrite solutions and methods to cope with low temperatures, including selecting suitable reactor types and culture methods. Meanwhile, we analyzed the interactions among the intermediates and the synergy between Anammox and denitrification and suggest the potential of applying Anammox for flue gas denitrification and anaerobic aromatic hydrocarbon biodegradation. Further studies are suggested regarding multifactor composite inhibition, Anammox physiological characteristics, and intermediate metabolic mechanisms as well as regarding methods for avoiding adverse factors in mainstream wastewater treatment. © 2018 Science Press. All rights reserved.  相似文献   

15.
The white rot fungi are members of Basidiomycota, which can degrade lignin and form white rot. They are high producers of extracellular laccases. In the present study, pure culture strain of high-temperature and high-laccase production types (numbered as BUA-01) was isolated from the fruiting bodies of a white rot fungus collected in the campus of Beijing University of Agriculture. The taxonomic characteristic was determined based on morphological and ITS sequence analysis. Furthermore, the optimal culture conditions for the mycelia were determined, including carbon source, nitrogen source, C/N ratio, growth factors, temperature, and pH. Extracellular laccase production was investigated in liquid fermentation with different concentrations of Cu (CuSO4) as inducer. Decolorizing activity of the fermentation broth was assayed using three azo dyes: Evans blue, methyl orange, and eriochrome black T. The results showed that the strain possessed the highest homology toward Trametes hirsuta, with the homology ratio of 100% and the genetic distance of 0, suggesting that the strain BUA-01 belonged to the genus Trametes. The culture condition investigated revealed that the optimal condition for mycelia growth included the following: carbon source, starch; nitrogen source, soybean powder and yeast extract; C/N ratio, 40/1 and 10/1; temperature, 37 °C; and pH, 6.0-7.0. The assayed growth factors had no significant effect on mycelial growth. It demonstrated high laccase activity in liquid fermentation. The highest extracellular laccase activity of 1 081.33 ± 6.3 U/mL was observed in the broth with a Cu adjunction concentration of 0.25 mmol/L after a 96-h culture period. It was about 26-fold higher than that of the control group. The isolated strain exhibited significant decolorizing activity toward the azo dyes Evans blue, methyl orange, and eriochrome black T, with the decolorization rate at 12 h of 93.31% ± 0.16%, 92.37% ± 0.42%, 79.25% ± 0.64%, respectively. This suggests that the strain possesses potential applications in laccase production and dye degradation. © 2018 Science Press. All rights reserved.  相似文献   

16.
Predation influences the ecology and behaviour of prey species and it is well known that the risk of predation affects prey’s decision making. We investigated whether predation risk through moon phase and exposure to the faecal odour of a natural predator, the red fox Vulpes vulpes, affect feeding behaviour and physiological response in wood mice (Apodemus sylvaticus). Antipredatory response was studied by live trapping under new and full moon in odourless control areas and areas experimentally manipulated with red fox fresh faeces. Food intake by individuals was determined as the amount of bait remaining in each trap and the physiological response was measured non-invasively analysing faecal corticosterone metabolites (FCM). Traps treated with faeces of red fox were the most avoided, and this avoidance was more significant during full moon. Food intake by wood mice varied according to the moon phase being significantly lower under full moon nights. We found sex, breeding condition and weight of individuals explaining the variation found in FCM concentrations, but no changes in FCM levels due to moon phase or exposure to red fox faeces were detected. These results indicate that wood mice avoid red fox faecal odour and this antipredatory response as well as feeding behaviour are significantly influenced by moon phase. However, no physiological response was found due to predation risk suggesting that wood mice do not take these predation cues enough reliable to experience physiological changes.  相似文献   

17.
The predominant pathway for human exposure to chromium in non‐occupationally exposed individuals is via food with a daily intake of around 30–100 μgd–1, with vegetables providing a major contribution. Unlike reports of chromium essentiality to man and animals, plants appear not to require chromium in spite of some early reports of a stimulatory growth effect.

Most reports on chromium in plants have been concerned with their growth on soils amended with sewage sludge, pF‐ash, tannery waste, or on ultra basic soils, which contain extreme concentrations of the element. Experimental studies with plants grown in hydroponic solution have often been undertaken at unrealistically high concentrations to examine the uptake of chromium in various forms, either as CrIII or CrVI at different pHs. In most cases, reports on chromium in plants deal with element concentrations and plant/soil relationships rather than detailed biochemical and physiological processes.

In general, chromium is largely retained in the roots of plants, although the oxidation state of chromium, pH, presence of humates and fulvates and plant species, affect plant uptake and transport. Leaves usually contain higher concentrations than grains. The uptake of CrIII is largely a passive process, whereas CrVI uptake is a metabolically mediated process via the sulphate pathway and is thus readily transported around the plant. The presence of a compound similar to trioxalate CrIII has been recorded while little chromium has been reported to be associated with cell organelles or soluble proteins.  相似文献   

18.
19.
In the present study, fruiting bodies of a wild medicinal mushroom, 'Huaier, ' were collected from Populus canadensis in the Beijing Xiangshan Park. The pure culture strain was obtained from fruiting bodies using the tissue isolation method. It was stored and numbered as XS-01. It was systematically classified using morphological and ITS identification. Further studies were focused on mycelia optimum culture conditions and laccase production by liquid fermentation. A 598-bp partial ITS region sequence (GenBank accession number KY93348) was obtained using PCR method. Phylogenetic tree and genetic distance analysis were performed using the MEGA 6.0 software. The present strain possessed the highest homology (100%) with Perenniporia robiniophila, and the genetic distances were 0.000. Based on the ITS sequencing and morphological characteristics of fruiting bodies and mycelia, XS-01 was identified as P. robiniophila. Based on mycelial growth rate and quality, mycelia optimum culture conditions were revealed to be as follows: the optimum carbon sources were starch and maltose, the optimum nitrogen source was yeast extracts, the optimum C/N ratio range was 30/1 - 60/1, the best growth temperature was 32 °C, the optimum pH was 7, and the optimum growth factor was VB1. Further study of Cu2+ on extracellular laccase production revealed that 1.0 mmol/L Cu2+ could significantly enhance the enzyme production, with the highest activity of 417.5 U/mL when cultured for 96 h and an increase ratio of 93.4% to the control. On the other hand, 2.0 mmol/L Cu2+ can markedly decrease the enzyme production laccase activity at 96 h to 79.0 U/mL, which was 36.6% of that of the control. In conclusion, a pure strain of T. robiniophila with high extracellular laccase activity was obtained, suggesting its potential application for artificial cultivation and laccase production. © 2018 Science Press. All rights reserved.  相似文献   

20.
Toxicity,degradation and analysis of the herbicide atrazine   总被引:3,自引:0,他引:3  
Excessive use of pesticides and herbicides is a major environmental and health concern worldwide. Atrazine, a synthetic triazine herbicide commonly used to control grassy and broadleaf weeds in crops, is a major pollutant of soil and water ecosystems. Atrazine modifies the growth, enzymatic processes and photosynthesis in plants. Atrazine exerts mutagenicity, genotoxicity, defective cell division, erroneous lipid synthesis and hormonal imbalance in aquatic fauna and nontarget animals. It has threatened the sustainability of agricultural soils due to detrimental effects on resident soil microbial communities. The detection of atrazine in soil and reservoir sites is usually made by IR spectroscopy, ELISA, HPLC, UPLC, LC–MS and GC–MS techniques. HPLC/LC–MS and GC–MS techniques are considered the most effective tools, having detection limits up to ppb levels in different matrices. Biodegradation of atrazine by microbial species is increasingly being recognized as an eco-friendly, economically feasible and sustainable bioremediation strategy. This review presents the toxicity, analytical techniques, abiotic degradation and microbial metabolism of atrazine.  相似文献   

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