Sugar receptor response of the food-canal taste sensilla in a nectar-feeding swallowtail butterfly, Papilio xuthus

The feeding behavior in nectar-feeding insects is triggered by a sugar-receptor response in contact chemosensilla. The contact chemosensilla are distributed not only on tarsi and the outside of the proboscis but also on the inside of the food canal in Lepidoptera. Although the chemosensilla inside the food canal are assumed to detect sweet taste during the passage of nectar through the food canal, their electrophysiological function has received little attention. In the nectar-feeding Asian swallowtail butterfly, Papilio xuthus (Lepidoptera: Papilionidae), we found 15- to 30-μm-long sensilla neatly lined up along the inside galea wall, which forms the food canal in the proboscis. The receptor neurons of these sensilla responded to sucrose. We hypothesized that starch and sucrose compete with each other for a taste receptor site on the sensilla. When we added starch and sucrose to the food-canal sensilla, the electrophysiological responses of food-canal sensilla were inhibited in parallel with the food-sucking behavior of the butterflies. These results suggest that the food-canal sensilla are involved in the behavioral control of nectar-sucking in this butterfly species.     

Diploid males, diploid sperm production, and triploid females in the ant Tapinoma erraticum

Under complementary sex determination (CSD), females of Hymenoptera arise from diploid, fertilized eggs and males from haploid, unfertilized eggs. Incidentally, fertilized eggs that inherit two identical alleles at the CSD locus will develop into diploid males. Diploid males are usually unviable or sterile. In a few species, however, they produce diploid sperm and father a triploid female progeny. Diploid males have been reported in a number of social Hymenoptera, but the occurrence of triploid females has hardly ever been documented. Here, we report the presence of triploid females, diploid males, and diploid sperm (produced by diploid males and stored in queen spermathecae) in the ant Tapinoma erraticum. Moreover, we show variations in the frequency of triploids among female castes: Triploid females are more frequent among workers than virgin queens; they are absent among mated, reproductive queens. The frequency of triploid workers also varies between populations and between nests within populations.     

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.     

Potential nitrogen enrichment of soil and surface water by atmospheric ammonia sorption in intensive livestock production areas

Elevated atmospheric NH₃ levels near intensive livestock operations can add significant N to local agroecosystems. In this study, the potential atmospheric NH₃ sorbed by soil and water was assessed over a 2-year period starting October 2000 in an intensive livestock production area in southern Alberta, Canada. Fifty-two uneven grid sampling sites were selected in the 53,905 ha study area. The sorption rate of atmospheric NH₃ was estimated weekly by exposing distilled water and air-dried soil samples to the atmosphere at the sampling sites. The increases in NH₄–N content in the samples after 1-week exposure was regarded as an index of the atmospheric NH₃ sorbed for that week. The NH₃ sorption rates were highly variable across the 52 sites, with water ranging from 4 to 125 kg ha⁻¹ year⁻¹ with a mean of 22 kg N ha⁻¹ year⁻¹ and soil from 5 to 84 kg N ha⁻¹ year⁻¹ with a mean of 20 kg N ha⁻¹ year⁻¹. Considerable variation in NH₃–N sorption across the study area reflects the effects of size, direction (upwind or downwind) and proximity of nearby livestock operations or other NH₃ sources and operators’ activities around the sampling sites. The NH₃ sorption rate at each site also varied considerably in response to weather conditions. The high rate of NH₃ input poses a direct risk of surface water eutrophication in intensive livestock operation areas. If fertilizer recommendations are not reduced to account for NH₃ sorption by soil, excess N may also contribute to eutrophication through runoff and leaching.     

生物滤池净化含铁锰高氨氮地下水试验研究

以中试有机玻璃滤柱反应器进行伴生高浓度氨氮含铁锰地下水生物同步净化试验研究,结果表明,进水氨氮浓度高于2.0mg/L时,溶解氧浓度是限制锰与氨氮去除的主要原因.下向流底部曝气过滤运行(气水逆向)可解决溶解氧不足的问题,但滤柱滤水能力有限;上向流底部曝气过滤(气水同向)同样可以满足铁锰氨氮氧化需氧量,然而曝气扰动作用削弱了滤池过滤截留能力造成铁锰氧化物穿透滤层,致使滤层出水铁锰浓度无法满足标准要求,曝气量越大,其滤池截留能力越弱.     

New findings on the generation of waste and emissions, and a modified cleaner production assessment approach-illustrated by leather production

New findings on the causes of waste and emissions, which were obtained from analysing numerous material streams in various sectors of industry, are presented in this article. It describes the implications of these findings for the vision of clean production, for formulating environmental policy concerning cleaner production targets, for the opportunities to assess to what extent the cleaner production targets have been met, and for the cleaner production assessment. A modified cleaner production assessment approach is presented, and illustrated using leather production as an example. The consequent implications for the diffusion of cleaner production are discussed.     

Structures and catalytic performances of Me/SAPO-34 (Me = Mn, Ni, Co) catalysts for low-tem perature SCR of NOx by ammonia

Me/SAPO-34 (Me = Mn, Ni, Co) series of catalysts were prepared by a wetness impregnation method and investigated for the selective catalytic reduction of nitrogen oxides with ammonia (NH₃-SCR). Among them, Mn/SAPO-34 catalyst was found as the most promising candidate based on its superior low-temperature activity. The catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy images (TEM), nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction and desorption (TPR and TPD), and diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS) of NH₃/NO_x adsorption. Mn/SAPO-34 is obviously different from Ni/SAPO-34 and Co/SAPO-34 in the active species state and distribution. Surface MnO_x species which play an essential role in NO oxidation and NO₂ adsorption, act as better active sites than nickel and cobalt mostly in the form of the aluminates and silicates.     

A comparison of measurements of atmospheric ammonia by filter packs,transition-flow reactors,simple and annular denuders and fourier transform infrared spectroscopy

Using data obtained during the 1985 Nitrogen Species Methods Comparison Study (1988,Atmospheric Environment22, 1517), several measurement methods for sampling ambient NH₃ are compared. Eight days of continuous measurements at Pomona College, a smog receptor site in Los Angeles, provided an extensive data base for comparing the following methods: Fourier transform i.r. spectroscopy (FTIR), three filter pack configurations, a simple and an annular denuder, and the transition flow reactor. FTIR was defined as the reference method and it reported hourly NH₃ concentrations ranging from > 60 to 2280 nmol m⁻³ (1.5−57ppb) during the course of the study, the highest values coming from the influence of nearby livestock operations.Although only limited quality assurance procedures were carried out, the following conclusions can, nevertheless, be drawn: most of the methods correlated highly with the FTIR method (correlation coefficientr > 0.96); generally, the linear regression slopes were close to unity and the intercepts were insignificantly different from zero at the 95% confidence level); relative to the FTIR average values, (1) for 4–6 h sampling periods, the averages of the three filter packs from three research groups were 83–130% and the annular denuder average was 87%, and (2) for 10–12 h sampling periods, the simple denuder averaged 90% and the two transition flow reactors were 77–98%. Possible reasons for the reported systematic biases are presented, but these are not able to fully explain the large range of differences reported by the various methods.     

A continuous-flow denuder for the measurement of ambient concentrations and surface-exchange fluxes of ammonia

A new diffusion denuder is described for the continuous measurement of atmospheric ammonia. Ammonia is collected in an absorption solution in a rotating denuder, separated from interfering compounds by diffusion through a semi-permeable membrane and detected by conductometry. The method is free from interferences by other atmospheric gases, with the exception of volatile amines. The detection limit is 6 ng m⁻³ for a 30-min integration time. This compact instrument is fully automated and suited for routine deployment in field studies. The precision is sufficiently high for micrometeorological studies of air-surface exchange of ammonia.     

负载量对氨水吸收CO2的影响规律及添加剂的作用研究

进行了氨法脱碳过程中吸收剂中CO2负载量对CO2脱除率影响的实验研究.结果发现,CO2脱除率随着负载量的增大而显著减小,高负载量(≥0.4)时,增加吸收液中总氨质量分数(吸收液中所有包含氨分子和铵离子的物质,并统一换算成NH3的质量分数)并不能有效地提高CO2的脱除率.同时,分别对有机和无机添加剂进行筛选,选取哌嗪(PZ)和十二水磷酸钠(Na3PO4·12H2O)对吸收剂中高CO2负载鼍条件下的氨水溶液进行改性.实验结果表明,当哌嗪(PZ)浓度与总氨浓度之比为0.08,在吸收荆中CO2负载量为0.4、0.5和0.6的条件下,CO2脱除率可分别提高29.4%、31.0%和21.7%;当Na3PO4·12H2O浓度与总氨浓度之比为0.10,在吸收剂中CO2负载量为0.4、0.5和0.6的条件下,CO2脱除率可分别提高11.0%、11.7%和17.1%.     

载体对镍基氨还原SO-2到元素硫催化剂性能的影响

用不同的载体（ＭｇＯ，α－Ａｌ２Ｏ３，γ－Ａｌ２Ｏ３和ＭｇＡｌ２Ｏ４）制备了４种镍基催化剂并对它们进行了氨还原ＳＯ２到元素硫反应活性评价。活性评价结果表明，由不同的载体制备的催化剂对该反应ＳＯ２的转化率和生成元素硫产率大小的影响次序均为：ＮｉＯ／ＭｇＯ〉ＮｉＯ／ＭｇＡｌ２Ｏ４〉ＮｉＯ／γ－Ａｌ２Ｏ３〉ＮｉＯ／α－Ａｌ２Ｏ３；而对生成硫选择性大小的影响次序则为：ＮｉＯ／ＭｇＯ〉ＮｉＯ／α－Ａｌ２Ｏ３     

闽江口鳝鱼滩芦苇湿地沉积物甲烷产生与氧化潜力对外源物质输入的响应

研究河口湿地沉积物甲烷(CH4)产生和氧化对外源物质输入的响应,对环境保护及温室气体减排具有重要意义.本研究基于室内培养-气相色谱法,探讨了闽江河口半咸水芦苇(Phragmites australis)沼泽湿地沉积物CH4产生与氧化对不同外源物质(底物、电子受体和营养物质)输入的响应.结果表明:CH3OH(500 mg·kg-1)、C3H9N(500 mg·kg-1)和Fe2+(0~500 mg·kg-1)对CH4产生潜力起促进作用(p0.05);NO-3(0~500 mg·kg-1)、NO-2(0~500 mg·kg-1)、Fe3+(50 mg·kg-1)和NH+4(50~500 mg·kg-1)表现为抑制CH4产生潜力(p0.05);而0~50 mg·kg-1的CH3OH和C3H9N、0~500 mg·kg-1的CH3COOH、SO2-4、Mn4+、PO3-4和低剂量的NH+4(0~5 mg·kg-1)对CH4产生的影响不显著(p0.05).实验剂量内(0~500 mg·kg-1),Fe3+和Mn4+的添加可促进CH4氧化(p0.05);CH3COOH、CH3OH、C3H9N、NO-3、NO-2、SO2-4、NH+4和低剂量的PO3-4(0~50 mg·kg-1)对沉积物CH4氧化潜力均有显著的抑制作用(p0.05);而Fe2+对CH4氧化没有显著影响(p0.05).综合分析表明,CH3COOH、CH3OH、C3H9N、NO-3、NO-2、SO2-4、PO3-4、NH+4和Fe2+的输入对沉积物CH4产生和氧化的综合作用为增加CH4排放通量,而Fe3+和Mn4+输入的综合作用则与之相反.     

基于PLFA法分析亚硝氮、硝氮和氨氮对厌氧微生物细菌群落的影响

利用磷脂脂肪酸(PLFA)技术研究了亚硝氮、硝氮和氨氮在不同浓度水平下对中温厌氧颗粒污泥中厌氧细菌群落结构的影响.结果表明,高浓度亚硝氮(360 mg·L-1,以N计)、硝氮(300 mg·L-1,以N计)和氨氮(3000 mg·L-1,以N计)使系统COD去除率分别下降至3.49%、10.85%和71.53%,并使污泥表面主要细菌由杆菌变为球状菌;亚硝氮和硝氮引起厌氧细菌和革兰氏阳性菌的含量下降,氨氮引起革兰氏阴性菌的含量下降;PLFA香农-威尔多样性指数随着亚硝氮和硝氮浓度的升高从1.12分别下降至0.96和1.03,氨氮对PLFA香农-威尔多样性指数无明显影响.     

Vaporization reduction characteristics of aqueous ammonia solutions by the addition of ethylene glycol, glycerol and glycine to the CO2 absorption process

Aqueous ammonia (NH₃) solution can be used as an alternative absorption for the control of CO₂ emitted from flue gases due to its high absorption capacity, fast absorption rate and low corrosion problem. The emission of CO₂ from iron and steel plants requires much attention, as they are higher than those emitted from power plants at a single point source. In the present work, low concentration ammonia liquor, 9 wt.%, was used with various additives to obtain the kinetic properties using the blast furnace gas model. Although a solution with a high ammonia concentration enables high CO₂ absorption efficiency, ammonium ions are lost as ammonia vapor, resulting in reduced CO₂ absorption due to the lower concentration of the ammonia absorbent. To decrease the vaporization of ammonia, ethylene glycol, glycerol and glycine, which contain more than one hydroxyl radical, were chosen. The experiments were conducted at 313 K similar to the CO₂ absorption conditions for the blast furnace gas model.     

Modification of nitrifying biofilm into nitritating one by combination of increased free ammonia concentrations, lowered HRT and dissolved oxygen concentration

Nitrifying biomass on ring-shaped carriers was modified to nitritating one in a relatively short period of time (37 days) by limiting the air supply, changing the aeration regime, shortening the hydraulic retention time and increasing free ammonia (FA) concentration in the moving-bed biofilm reactor (MBBR). The most efficient strategy for the development and maintenance of nitritating biofilm was found to be the inhibition of nitrifying activity by higher FA concentrations (up to 6.5 mg/L) in the process. Reject water from sludge treatment from the Tallinn Wastewater Treatment Plant was used as substrate in the MBBR. The performance of high-surfaced biocarriers taken from the nitritating activity MBBR was further studied in batch tests to investigate nitritation and nitrification kinetics with various FA concentrations and temperatures. The maximum nitrite accumulation ratio (96.6%) expressed as the percentage of NO2??-N/NOx??-N was achieved for FA concentration of 70 mg/L at 36°C. Under the same conditions the specific nitrite oxidation rate achieved was 30 times lower than the specific nitrite formation rate. It was demonstrated that in the biofilm system, inhibition by FA combined with the optimization of the main control parameters is a good strategy to achieve nitritating activity and suppress nitrification.     

Critical review of EPS production, synthesis and composition for sludge flocculation

Extracellular polymeric substances(EPS) produced by microorganisms represent biological macromolecules with unfathomable potentials and they are required to be explored further for their potential application as a bioflocculant in various wastewater sludge treatment. Although several studies already exist on biosynthetic pathways of different classical biopolymers like alginate and xanthan, no dedicated studies are available for EPS in sludge. This review highlights the EPS composition, functionality, and biodegradability for its potential use as a carbon source for production of other metabolites. Furthermore, the effect of various extraction methods(physical and chemical) on compositional, structural, physical and functional properties of microbial EPS has been addressed. The vital knowledge of the effect of extraction method on various important attributes of EPS can help to choose the suitable extraction method depending upon the intended use of EPS. The possible use of different molecular biological techniques for enhanced production of desired EPS was summarized.     

莠去津降解菌HB-5的最佳产酶培养基及发酵条件

从农药厂废水中分离到一株降解莠去滓的节杆菌(Arthrobacter sp.)HB-5,以从该菌中提取到的降解酶对莠去津的降解率为指标,进行最佳产酶培养基及发酵条件的优化研究,对其产酶量进行了评价.通过正交试验和均匀试验,对细菌HB-5的发酵培养基进行了优化研究.运用SAS软件进行结果分析,所获优化培养基配方为:蔗糖3.0g·L-1,莠去津0.38g·L-1,K2HPO40.5g·L-1,KH2PO41.2 g·L-1,MgSO4·7H2O 1.2g·L-1,NaCl 0.1g·L-1,微量元素溶液3.8mL·L-1.得到菌株培养的最佳优化条件为:菌株发酵液培养时间为48h.接种量为2%,发酵液初始pH值为9,250mL三角瓶中装液量为80mL经优化后,降解酶对莠去津的降解率(91.64%)比原培养基(40.67%)提高了125%.