取代苯甲酸在天然河流中的生物降解及其定量结构--生物降解性相关研究

以天然河流水作为微生物源 ,采用碘量法测定了 2 0种苯甲酸类化合物的 5日生化需氧量 ,并以其占理论需氧量的百分数作为表征生物降解性的参数 ,得出各类取代苯甲酸类化合物的生物降解能力为 :羟基 >氨基 >羧基 >甲氧基 >氯基 >硝基 ;对于同一种取代基 ,对位取代基化合物生物降解能力最大 ,而邻位、间位取代基化合物生物降解能力大体相同。计算了苯甲酸类化合物的分子连接性指数 ,并以 5日生化需氧量占理论需氧量的百分数为参数建立了 QSBR模型。分析结果表明 ,分子连接性指数5Xvpc、5Xp- 5Xvp 能较好地反映取代苯甲酸的生物降解性     

Water solubility enhancements of PAHs by sodium castor oil sulfonate microemulsions

Water solubility enhancements of naphthalene( Naph), phenantherene(Phen) and pyrene(Py) in sodium castor oil sulfonate(SCOS) microemulsions were evaluated. The apparent solubilities of PAHs are linearly propertional to the concentrations of SCOS microemulsion, and the enhancement extent by SCOS solutions is greater than that by ordinary surfactants on the basis of weight solubilization ratio(WSR). ThelogKcm values of Naph, Phen, and Py are 3.13, 4.44 and 5.01 respectively, which are about the same as the logKow values. At 5000 mg/L of SCOS conccentration, the apparent solubilities are 8.80, 121, and 674 times as the intrinsic solubilities for Naph, Phen, and Py. The effects of inorganic ions and temperature on the solubilization of solutes are also investigated. The solubilization is improved with a moderate addition of Ca^2 , Na^ , NH4^ and the mixture of Na^ , K^ , Ca^2 , Mg^2 and NH4^ . WSR values are enhanced by 22.0% for Naph,23.4% for Phen, and 24.6% for Py with temperature increasing by 5~C. The results indicated that SCOS microemulsions improve the performance of the surfactant-enhanced remediation(SER) of soil, by increasing solubilities of organic pollutants and reducing the level of surfactant pollution and remediation expenses.     

The effect of metapleural gland secretion on the growth of a mutualistic bacterium on the cuticle of leaf-cutting ants

In Acromyrmex octospinosus leaf-cutting ants the metapleural glands produce an array of antibiotic compounds that serve as a general defence against unwanted microbes on the cuticle. Leaf-cutting ants also grow mutualistic Pseudonocardiaceae bacteria on their cuticle that produce antibiotics controlling a microfungal parasite of their fungus gardens. Interaction between this bacterium and gland secretion therefore seems unavoidable. We document the typical development of bacterial growth on the cuticle of young major workers, show that growth starts a few days after eclosion, and that the maximal cover is reached after 2–3 weeks and gradually declines when workers mature. Experimental closure of the metapleural glands had no effect on the initial exponential growth phase of the bacterium, but significantly reduced the cover during the decline phase. The age-dependent abundance of the bacterium and its partial dependence on metapleural gland secretion support the hypothesis that the abundance of this mutualist is actively regulated.     

The influence of sewage sludge properties on sludge-borne metal availability

With the advent of more stringent controls on wastewater treatment, sewage sludge production in Europe and many parts of the world is increasing. With this increase comes the problem of sludge disposal, and recycling to land arguably offers an economically and environmentally sustainable option. However, a major limitation of sewage sludge reuse is the potential release of heavy metals from the sludge and heavy metal accumulation to toxic levels in topsoils. The properties of the sludge play a crucial role in determining the initial release and subsequent availability of heavy metals in amended soils. Bioavailable forms of heavy metals in recently amended soils are most likely to be those that are bioavailable in the sewage sludge. In this paper, published research on the importance of sewage sludge characteristics on metal release and bioavailability will be reviewed and contrasted with original research. A selection of sludges from around Australia has been collected for this purpose. Through the use of incubation studies, isotope dilution techniques, ion-selective electrode measurements and ¹³C-NMR spectroscopy, the importance of a range of sludge properties on heavy metal behaviour in sludges and sludge-amended soils is addressed.     

Trace element speciation in selected smelter-contaminated soils in Anaconda and Deer Lodge Valley, Montana, USA

Long-term copper smelting in the Anaconda and Deer Lodge Valley area of Montana has resulted in an extensive area of trace element contamination. Aerial extent of contamination is generally established, but total analysis of soils does not correlate to relative degree of impact on vegetation growth. Three pedons (Beaverell, Cetrack and Judco) were analyzed by routine soil characterization methods, aqua regia microwave digestion, sequential chemical extraction, and X-ray diffraction analysis with the objective of providing a better understanding of chemical forms and potential reactivity of selected trace elements (Cd, Co, Cr, Cu, Hg, Mn, Ni, P, Pb). Surface horizons of soils are more acidic than subsoils, with pH for all horizons ranging from 4.0 to 8.7. Beaverell is the most contaminated in the upper 20 cm with the sum of total extractable (SUM_TE) trace elements by microwave digestion ranging from 1836 to 3605 mg kg⁻¹, largest H₂O-soluble (WS) and exchangeable (EX) fractions (e.g. 1.6 and 9.3%, respectively), and smallest residual (RES) fraction (e.g. 14.3%). Cetrack has greater SUM_TE elements than Judco, though a lower WS+EX fraction due to the effects of alkaline pH, carbonates and high P. Oxide (OX), organic matter/sulfide (OM/S), and RES fractions predominate over WS, EX, and specially-sorbed/carbonate-bound fractions (SS/CAR) for all horizons. Copper, Zn, Pb and Cd are elevated in surface over subsurface horizons in these latter fractions, indicating these elements were anthropogenic additions. X-ray data indicate that Pb, Cu, Cr and Cd partially exists as both OX and sulfide mineral forms.     

Gamergates in the myrmicine genus <Emphasis Type="Italic">Metapone</Emphasis> (Hymenoptera:Formicidae)

Gamergates (i.e. mated reproductive workers) are mostly known from ant species within the Ponerinae. We report here the discovery of gamergates in two species of the subfamily Myrmicinae. Until now, mated reproductive females in colonies of myrmicine species have been considered morphologically distinct from the worker caste. However, in two species of the myrmicine Metapone (Metapone madagascarica and a newly discovered, not yet described Metapone species) all workers have six ovarioles and a spermatheca; and some of them are mated. There are no morphological differences between mated and non-mated workers. Field observations and laboratory studies indicate that colonies of the Metapone species can reproduce with gamergates only.     

Transient division of labor and behavioral specialization in the ant Formica schaufussi

Cooperative prey retrieval in the monomorphic ant Formica schaufussi is carried out by workers that perform functionally distinct roles which persist only for the duration of a single retrieval event. A forager (scout) that locates prey too large to retrieve individually organizes cooperative prey transport by recruiting nestmates (recruits) to assist in retrieval. The scout and recruit roles appear to be determined by whether a worker activates recruitment or is recruited from the nest. Scouts organize recruitment and play a key role in maintaining the cohesion of the retrieval group. If a scout that has initiated group transport is experimentally removed, the recruited workers composing the retrieval group typically abandon the prey and cooperative foraging is terminated. In this context, recruits are unable to function as scouts and reorganize group transport. Individuals marked as recruits in one prey retrieval, however, can switch and act as scouts in subsequent retrievals. Because the roles of individuals persist within but not between retrieval events, the specialization involved in cooperative prey retrieval cannot easily be explained as a response associated with age-related or genetic predispositions. This transient division-of-labor, in which individual roles may persist only for the duration of a single group action, represents a novel type of short-term individual specialization.     

Occurrence,functions and biosynthesis of polyamides in microorganisms and biotechnological production

Microorganisms are able to synthesize three different polyamides by enzymatic processes independently from ribosomal protein biosynthesis: poly(gamma-D-glutamic acid), poly(epsilon-L-lysine) and multi-L-arginyl-poly(L-aspartic acid) which is also referred to as cyanophycin. These polyamides, which occur mainly in Bacillus spp. (and only a few other eubacteria and the nematocysts of Cnidaria, in Streptomyces albulus or in cyanobacteria, respectively), have recently attracted considerable interest of the chemical industry and may be suitable for various applications. This review summarizes our current knowledge on the occurrence, biosynthesis, physiological functions, and biodegradation as well as on the properties and putative applications of these polyamides. Emphasis is placed on the enzymology of the polymerization and on the genes encoding the polymerizing enzymes, which have only recently become available for cyanophycin synthetases. Prospects for novel production processes. in particular for cyanophycin, are also presented.     

Sustainable development pattern and the strategy in the three Gorges Reservoir Areas

The development pattern,development situation,and existing problems of land exploitation in Zigui County,Three Gorges Reservoir Areas of China were presented.The sustainable development mode and its strategy in the Three Gorges Reservoir Areas was also discussed.A sustainable development framework for low mountain regions,middle mountain regions and high mountain regions was developed,and management countermeasures for structural optimization of complex ecosystems were advanced.     

佳木斯台形变观测对东北地区几次浅震“场兆”异常的探讨

大地震在主破裂前往往行成地壳变形,高应力作用下进入峰值后的变形阶段,反映到地倾斜观测日均值曲线上,表现为固体潮形变趋势异常,这些异常能否指示远距离的地震,近年来不少研究者发现,远场前兆往往出现在对应力、应变变化反应灵敏的特殊构造部位。佳木斯台可能处于这种特殊的构造部位,对东北地区浅源地震短期前兆异常“场兆”的趋势性变化具有一定的意义。