固定化微生物技术在受污养殖水体和水华水域生物修复中的应用

固定化微生物技术作为一种新型的生物修复技术,具有高效、稳定、生物安全性较高等特点,已经广泛应用于各种污染水体的净化修复之中,也包括受污染日益严峻的近海养殖水体。综述从固定化微生物技术的出现和应用出发,对不同固定方法的优劣及其所擅长降解的污染物类型进行对比,对不同载体的特点进行分析,总结了固定化微生物技术在近海养殖水体污染修复的研究概况,并对当前该技术应用存在的问题进行分析和未来研究的方向进行展望。     

Determination of heavy metals in the fruit of date palm growing at different locations of Riyadh

Exposure of heavy metals to human beings has risen dramatically in the last 50 years. In today’s urban and industrial society, there is no escaping from exposure to toxic chemicals and heavy metals. Humans are more likely to be exposed to heavy metal contamination from the dust that adheres to edible plants than from bioaccumulation. This is because it is very difficult to wash off all the dust particles from the plant material before ingesting them. The objectives of this experiment were to determine the concentrations of lead (Pb) and cadmium (Cd) in washing residues and in the tissues of fruits of date palm growing in 14 sites of Riyadh and also to assess whether the fruits were safe for human consumption. The washing residues and tissue of date palm fruits collected from different sites showed the presence of significant amounts of the Pb and Cd. The concentration of Pb in the dust and fruit tissue increased with increasing anthropogenic sources. Therefore, fruits of date palm might be used as a pollution indicator; it might be recommend that fruits of date palm could be safe for human consumption after washing. The mean concentration of Pb and Cd in all the samples collected from different sites is within the safe limits recommended by FAO/WHO.     

Effect of ionic liquids activation on laccase from Trametes versicolor: Enzymatic stability and activity

The stability and activity of laccase from Trametes versicolor in two water‐soluble ionic liquids (ILs), namely 1‐butyl‐3‐methylimidazolium methyl sulfate, [bmim][MeSO₄] and 1,3‐dimethylimidazolium methyl sulfate, [mmim][MeSO₄], were investigated in this study. Thermal inactivation of laccase was characterized in the presence of these both ILs and as expected first‐order kinetics was followed. Inactivation rate constant (k), half‐life time (t_1/2), and energy of activation (Ea) were determined. Kinetics of 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid) oxidation by laccase in the presence of these ILs was studied and Michaelis–Menten parameters were calculated. There is no enzymatic inactivation since the maximum reaction rate remained constant for IL concentrations up to 25%, and surprisingly, it was found that laccase was activated for concentrations of 35% of ILs, since the reaction rate increased 1.7 times.     

Identification of hot spots within harbour sediments through a new cumulative hazard index. Case study: Port of Bari,Italy

While numerous quality guidelines unquestionably drive the management of harbour sediments, port managers increasingly require easy-to-use tools supporting them in assessing the sediment quality. In this work, a new hazard index, named cumulative Normalized and Weighted Average Concentration (c_NWAC), is proposed, considering the concentrations of main hazardous, toxic and bio-accumulative sediment contaminants. This index is an upgraded version of the previously introduced NWAC index, which considered only the metal concentrations. The c_NWAC values range from 0 to 10 scores, and their visualization on a colour base code map leads to an easy identification of hotspots. The applicability of the new index was verified using a dataset derived from the analyses of 42 samples collected at different depths of the seabed of the Port of Bari (Italy). The concentrations of 58 parameters were considered, namely 11 metals and metalloids, 17 congeners of polychlorinated biphenyls (PCBs), 16 congeners of polycyclic aromatic hydrocarbons (PAHs), further 11 organic micropollutants, total organic carbon (TOC) and nutrients (N_tot, P_tot). For the study area, the obtained c_NWAC values resulted well correlated to the corresponding values of the commonly used mean Effects Range Median quotient (mERMq), and similar hazard categories were developed for the new index, even if the latter do not necessarily explain the real sediment toxicity, because they were derived from a different sediment dataset and different test species.Moreover, the hazard predictive ability of the new index was verified (with satisfactory results) by testing the considered samples by eco-toxicological assays, using three different biological species, and comparing the obtained results to the corresponding hazard categories developed for c_NWAC.     

A model for the time–temperature–mortality relationship in the chill-susceptible beetle, Alphitobius diaperinus, exposed to fluctuating thermal regimes

Exposing insects to a fluctuating thermal regime (FTR) compared with constant low temperature (CLT) significantly reduces cold-induced mortality. The beneficial effects of FTR result from physiological repair during warming intervals. The duration and the temperature experienced during the recovery period are supposed to strongly impact the resulting cold survival; however, disentangling the effects of both recovery variables had not been broadly investigated. In this study, we investigate cold tolerance (lethal time, Lt₅₀) of the polyphagous beetle Alphitobius diaperinus. We examined adult survival under various CLTs (0, 5, 10 and 15 °C), and under 20 different FTR conditions, where the 0 °C exposure alternated with various recovery temperatures (Rt) (5, 10, 15 and 20 °C) combined with various recovery durations (Rds) (0.5, 1, 2, 3 and 4 h). Under CLTs, Lt₅₀ increased with temperature until no mortality occurred above the upper limit of cold injury zone (ULCIZ). Under FTRs, Lt₅₀ increased with both Rt and Rd. The magnitude of the survival gain was clearly boosted when Rt was above the ULCIZ (at 20 °C). Based on a data matrix of lethal times with multiple Rt×Rd combinations, a predictive model showed that cold survival increased exponentially with Rt and Rd. This model was subsequently validated with additional survival tests. We suggest that increasing recovery durations associated with optimal recovery temperatures eventually leads to a progressive chilling compensation.     

Investigations of antiproliferative and antioxidant activity of β-lactam morpholino-1,3,5-triazine hybrids

This article reports for the first time the synthesis of some novel β-lactam morpholino-1,3,5-triazine hybrids by a [2+2]-cycloaddition reaction of imines 7a–c, 9a–c and 11 with ketenes derived from substituted acetic acids. The reaction was totally diastereoselective, leading exclusively to the formation of cis-β-lactams 8a–l, 10a–f and 12a–c. The synthesized compounds were tested for activity towards SW1116, MCF-7 and HepG2 cancer cell lines and non-cancerous HEK-293 cell line by MTT assay. None of the compounds exert an observable effect on HepG2, MCF-7 and HEK-293 cells, but compounds 7b, 8f, 8g, 8l, 10c, and 10e exhibited excellent growth inhibitory activity (IC₅₀ < 5 µM) against SW 1116 cells, comparable to that of doxorubicin (IC₅₀ = 6.9 µM). An evaluation of the antioxidant potential of each of the compounds, performed by diphenylpicrylhydrazyl (DPPH) assay, indicated that 7b, 9a, 9b and 9c have strong free radical scavenging activity. UV absorption titration studies reveal that 7b, 8l, 8g and 8f interact strongly with calf-thymus DNA (CT-DNA) in the order of 8l > 7b > 8f > 8g. Collectively, the in vitro capabilities of some of these morpholino-triazine imines and β-lactams suggest possible applications to development of new antioxidants and DNA binding therapeutics.     

A transient thermal model of the human body–clothing–environment system

This paper reports on a new transient thermal model integrating the heat and moisture transfer through clothing as well as the two-node human physiological model to predict the human physiological responses. For the first time, the model considered clothing ventilation and moisture accumulation on the surface of the skin and inner surface of the underwear. The numerical results of the model agreed well with a set of published experimental data and another set of experimental data from our own experiments.     

Cross Tolerance to Environmental Stressors: Effects of Hypoxic Acclimation on Cardiovascular Responses of Channel Catfish (Ictalurus punctatus) to a Thermal Challenge

Hypoxia and temperature are two major, interactive environmental variables that affect cardiovascular function in fishes. The purpose of this study was to determine if acclimation to hypoxia increases thermal tolerance by measuring cardiovascular responses to increasing temperature in two groups of channel catfish. The hypoxic group was acclimatized to moderate hypoxia (50% air saturation, a P_O2 of approximately 75 Torr) at a temperature of 22 °C for 7 days. The normoxic (i.e. control) group was maintained the same, but under normoxic conditions (a P_O2 of approximately 150 Torr). After acclimation, fish were decerebrated, fitted with dorsal aorta cannulae, and then exposed to increasing temperature while cardiovascular variables were recorded. The endpoint (critical thermal maximum, CTMax) was defined as a temperature at which heart rate and blood pressure sharply decreased, indicating cardiovascular collapse. Fish acclimatized to moderate hypoxia had higher resting heart rate than controls. Hypoxic acclimatized fish had a significantly higher CTMax. Acclimation to hypoxia increases the cardiovascular ability of channel catfish to withstand an acute temperature increase.     

Index of size distribution (ISD): a method of quality assessment for coastal lagoons

A new index was developed as a tool for quantifying the degree of disturbance in lagoons in order to meet the objective of Ecological Quality Status (EcoQ), using the zoobenthos quality element. The Index of Size distribution (ISD) is proposed to assess the ecological quality status of coastal lagoons. It represents the skewness of the distribution of individuals of a benthic community in geometric size (biomass) classes. The ISD was applied in three coastal lagoons with different levels of disturbance and classified them as of good, moderate and poor ecological quality. A scheme for the classification of EcoQ in lagoonal systems is presented. The index showed a strong relationship with the percentage of organic carbon in the sediment, as well as with the dissolved oxygen concentrations. ISD having the advantage of good discriminating power and not demanding high taxonomic resolution, could be a simple and promising tool to be further applied and tested in Mediterranean lagoons.     

Implications of microhabitat selection and patterns of activity on the thermal ecology of high elevation neotropical anurans

This paper focuses on whether microhabitat selection reduces exposure to cold temperatures in highelevation tropical amphibians. I studied the microhabitat associations and thermal ecology of four anurans (Colostethus subpunctatus, Atelopus sp. nov., Eleutherodactylus bogotensis, and Hyla labialis) that live in the Andes of central Colombia. I compared two populations (3500 m and 2900 m) to evaluate the impact of a change in elevation on microhabitat thermal regimes and frog behavior. Ambient temperatures of frequently used microhabitats (soil surface, retreat sites, bogs, and ponds) were significantly lower at 3500 m. However, for each species the microhabitat associations and general patterns of activity were similar at both elevations. Body temperatures of active frogs were mainly determined by the interaction between microhabitat selection and time of the day, therefore frogs at 3500 m had lower activity temperatures than conspecifics at 2900 m. Terrestrial and diurnal anurans (Atelopus sp. nov.) experienced highly variable activity temperatures. Frogs associated with water bodies (C. subpunctatus, and H. labialis) experienced more moderate and less variable temperatures. Terrestrial, nocturnal frogs (E. bogotensis) exhibited the lowest activity temperatures, and their thermal ecology was strongly affected by increase in altitude. The physical nature of high tropical elevations limits the opportunities for behavioral thermoregulation in amphibians, and increases the importance of physiological adjustments to tolerate a wide thermal range. This may partially explain why only a small number of amphibian species, representing genera that are much more diverse at lower elevations, have been able to exploit these environments.