Impact of low dose of organophosphate, monocrotophos on the epithelial cells of gills of Cyprinus carpio communis Linn.--SEM study

The paper deals with the deleterious changes at ultrastructural level of the epithelial cells of gills of Cyprinus carpio communis Linn. upon exposure to 1/10th of LC50 of monocrotophos which is considered to be insignificant concentration from toxicological point of view. The gills of the fish are the primary corridor formolecularexchange between the internal milieu of a fish and its environment. Gills perform numerous functions such as oxygen uptake and CO2 excretion, osmoregulation, acid-basic balance, excretion of nitrogenous compounds and taste. Hazardous chemicals present in water may alter the morphology of the epithelial cells of gills of the fish, which may affect the process of diffusion of gases and ultimately the overall health of the fish. To prove this fact Cyprinus carpio communis Linn. was kept in water for 30 days having low concentration of 0.038 ppm (1\10th of LC50) of monocrotophos and an attempt was made to study the different types of degenerations produced in the epithelial cells of gills as compared to the normal epithelial cells of gills of this culturable fish using Scanning Electron Microscope (SEM) technique. The ultrastructural changes due to the toxic exposure at finer scale were thinning of microridges, upliftment of epithelial cells, development of hyperplasia, decrease in the density of mucous cells which are considered to be the first line of defence and total dystrophy of epithelial tissue. Thus, it is opined that a low concentration of monocrotophos has the potential to bring different type of degenerations at finer scale hence affecting the fish's health drastically and altering the fitness of the fish in water even having insignificant amount of this toxicant in the ambient water     

Feeding and cleaning mechanisms in the suspension feeding bivalve Mytilus edulis

Feeding and pseudofeces formation were studied in intact Mytilus edulis clearing suspensions of graphite particles, and the processes were compared with activities observed in mussels with a severed adductor muscle. Most particulate material in the stomach was present in the suspended state. Ingestion of particles in suspension could take place concurrently with the production of pseudofeces. Severing of the adductor muscle resulted in profuse secretion of mucus that gradually subsided to a constant low level. Addition of graphite particles at concentrations that did not cause mucus secretion in the intact mussels strongly stimulated secretion in the operated mussels, resulting in the accumulation of highly viscid, mucusparticle aggregates. These aggregates were mechanically stable, in contrast to the fragile pseudofeces. It is indicated that normal feeding depends upon hydromechanical mechanisms that produce highly concentrated suspensions of particles for ingestion, and that mucociliary mechanisms serve to clean the gills and other organs of the mantle cavity for excess particulate material. It is further indicated that intact mussels secrete mucus only in the amounts needed to consolidate excess particulate material, and that lesions affect the normal balance between particles in suspension and mucus secretion by enhancing the sensitivity of the mechanisms that control mucus secretion.     

Mode of particle ingestion in five species of suspension-feeding bivalve molluscs

In order to elucidate the mode of particle ingestion and the functional anatomy of the oesophagus in bivalves, a histological study was performed onMytilus edulis (Mytilidae),Crassostrea virginica (Ostreidae),Placopecten magellanicus, Chlamys varia, and juvenilePecten maximus (Pectinidae). Specimens were sampled from various sites in New Brunswick, Canada, and Brittany, France, from 1987 to 1989. The buccal, peribuccal, and oesophageal epithelia of all species contained a dense distribution of actively secreting mucocytes, although these were somewhat less abundant inCrassostrea virginica, which also has the shortest oesophagus. Mucocyte morphology, while constant within a family (Pectinidae), showed clear differences among families. Both acid and neutral mucopolysaccharides were secreted by the epithelial mucocytes of all species. Mucus and mucus-particle masses were observed in the peribuccal and buccal regions, as well as in the oesophageal lumina of all species, even in those specimens which had been maintained without feeding (Placopecten magellanicus) or held out of water for 48 h (C. virginica) prior to dissection and fixation. These results indicate that a basal level of mucus production and transport is continuous on the peribuccal, buccal, and oesophageal ciliated epithelia, regardless of the particle concentration in the external medium. Buccooesophageal glands, generally thought to be absent in the Bivalvia, were observed in one of the species examined (M. edulis). It is concluded that the mode of particle ingestion in these suspension-feeding bivalves is via ciliatransported mucus masses; the presence of buccooesophageal glands inM. edulis suggests a digestive role for the oesophagus in this species.     

Effects of some trace heavy metals on Poecilia reticulata (Peters)

Three trace heavy metals viz., nickel, copper and zinc were studied for their toxic action against Poecilia retriculata (Peters). Among these, copper was found to be most active followed by zinc and nickel. Accumulations of these metals as well as behavioural studies were carried out after exposing fish to sub-lethal concentration of LC20. It was found that the highest quantity of nickel was accumulated in the fish body followed by zinc and copper. After exposure to sub-lethal concentration of metals some behavioural changes in fish were observed due to stress, such as mucus like secretion over gills, excessive excretion, anoretic condition and increased distance between gills and operculum. In all the cases fin movement was observed. Role and use of such changes as biological indicators or as biological early warning system in water quality assessment has been discussed.     

Management of nematocysts in the alimentary tract and in cnidosacs of the aeolid nudibranch gastropod<Emphasis Type="Italic"> Cratena peregrina</Emphasis>

The nudibranch gastropod Cratena peregrina (Opisthobranchia: Aeolidaceae), when feeding on polyps of the hydrozoan Eudendrium racemosum (Cnidaria: Anthoathecata), devours masses of small microbasic eurytele and holotrichous isorhiza nematocysts. Large proportions of these nematocysts were found undischarged in the alimentary tracts of the snails. Feeding experiments in this study tracked the fate of nematocysts as they passed through the alimentary canal to the digestive gland in the dorsal appendages, the cerata, to the cnidosacs, and finally in the faeces. In digestive cells, many structurally intact nematocysts were present in large phagosomes that remained unaffected even after 2 days fasting, and phagosomes containing nematocysts were found in the faeces. Thus, it is inferred that fusion of nematocyst-containing phagosomes with lysosomes and subsequent digestion of nematocysts is blocked. Masses of exposed, undigested and structurally intact nematocysts were discarded in the faeces. In the tips of the cerata, other nematocysts were phagocytosed by cnidophages and stored in the cnidosacs. After release, in contact with seawater, cnidosac nematocysts were able to discharge. When cnidophore tentacles of E. racemosum with only holotrichous isorhizas were fed to the snails, the isorhizas arrived in the cnidosacs about 2 h after feeding and mixed with existing small euryteles. Some cnidosacs also contained very large microbasic eurytele or large macrobasic eurytele nematocysts, possibly from Eudendrium ramosum and Eudendrium glomeratum, respectively. This indicates that the various types of nematocysts from food were all incorporated into the cnidosacs. Evidence for a selection process or digestion of a certain nematocyst type in the cnidophages was not obtained. It is concluded that a large proportion of the nematocysts ingested with the food are not digested, but are eliminated, structurally and functionally intact, via the alimentary canal and the tips of the cerata.     

柴油污染土壤生物修复对土壤酶活性的影响

在柴油污染土壤的生物修复过程中,分析了土壤中柴油降解菌数量和3种土壤酶活性(过氧化氢酶、脱氢酶和脂酶)等生物活性指标与土壤中柴油去除率的相关性.结果表明,土壤受到柴油污染后的一段时间后过氧化氢酶、脱氢酶和脂酶的活性上升,而后随着土壤中石油烃的降解,脂酶又不断降低.进一步分析表明脂酶活性与柴油降解率及柴油降解菌数量都具有很好的正相关性,可以采用土壤脂酶活性来指示柴油生物降解成效.     

雏鸭鸭瘟诊断初探

鸭瘟是对养鸭业危害很大的一种病毒性传染病，具有高度的传染性和致死率．常见有肿头、流泪、体温升高的典型症状以及消化道充血、出血、纤维素性坏死性炎症和肝脏坏死灶、出血等典型病变．本文报告一例鸭瘟病例的发病和诊断．     

Alkyl polyglucosides as cell surface modification factors: influence of the alkyl chain length

The use of surfactants in a bioremediation process is aimed at increasing the efficiency of the removal of hydrophobic contaminants from the environment. The subjects of the study were three alkyl polyglucosides (APGs) of different alkyl chain length: Glucopon 215 CS UP, Glucopon 600 CS UP, and Glucopon 650 EC. The impact of these surfactants on the surface properties of the test strain Pseudomonas fluorescens ATCC 14700, as well as on the biodegradation of diesel was tested. It was observed, that the length of alkyl chain has an influence on the cell surface properties. The modification of the cell surface hydrophobicity and the electrokinetic potential on the bacteria cells is dependent on the structure of Glucopon molecules. The elongation of alkyl chains in surfactant molecule caused an increase of the hydrophobic properties and a reduction of the electrokinetic potential on the bacteria cells. Moreover, the use of APGs below critical micelle concentration caused an increase of diesel oil biodegradation, especially in the case of Glucopons with longer alkyl chain (Glucopon 600 CS UP and 650 EC). The better diesel oil removal by tested strain after surfactant addition was correlated with the hydrophobic properties of bacteria strain.     

Effect of Diesel Fuel on Growth of Selected Plant Species

Diesel oil is a complex mixture of hydrocarbons with an average carbon number of C8–C26. The majority of components consist of alkanes, both straight chained and branched and aromatic compounds including mono-, di- and polyaromatic hydrocarbons. Regardless of this complexity, diesel oil can be readily degraded by a number of soil microorganisms making it a likely candidate for bioremediation. The concept of using plants to enhance bioremediation, termed phytoremediation, is a relatively new area of scientific interest. It is particularly applicable to diesel oil contamination as diesel oil generally contaminates the top few metres of soil (surface soil) and contamination is not uniform throughout the site. By encouraging plants to grow on diesel oil contaminated soil, conditions are improved for the microbial degradation of the contaminant. During this study, establishing plants on diesel oil contaminated soil proved difficult. Diesel oil is phytotoxic to plants at relatively low concentrations. At concentrations below this phytotoxic level, the development of plants grown in diesel oil contaminated soil differs greatly from plants grown in uncontaminated soil. Tolerance of plants to diesel oil and ability to germinate in diesel oil contaminated soil varied greatly between plant species as well as within plant species. The broadest differences in germination were seen within the grasses with certain species thriving in low levels of contamination (e.g. Creeping bent) while others were intolerant of diesel oil contamination (e.g. Rough meadow grass). The herbs, legumes and commercial crops screened appeared to be largely unaffected by low levels of diesel oil contamination (25g dieselkg^–1). At the higher level of contamination (50g dieselkg^–1), half of the twenty two plants species screened failed to reach a germination rate equal to 50% of the control rate. Two species of grass failed to germinate at all at this contamination level. Plant species that successfully germinated and grew were studied further to determine the effect of diesel oil contamination on the later stages of plant development. This work investigates the effect of diesel oil on plant growth and development.     

Histology and ultrastructure of the skin of Lepadichthys lineatus (Gobiesocidae: Teleostei)

The skin of the Red Sea clingfish Lepadichthys lineatus Briggs, 1966, which lives on shallow-water crinoids, consists of a continuous layer of giant mucus-producing cells. Upon stimulation, these cells are able, in seconds, to envelope the fish entirely with a thick layer of their secretion. The cells are 75 to 290 high, and are enveloped by septa of compressed epithelium. They rest on a strong collagenous layer, and extend to the skin surface, where they open. The nuclei of the giant cells are large, and irregularly shaped; their cytoplasm has a very extensive endoplasmic reticulum and undergoes deep structural changes during maturation. Their ability to produce large amounts of mucus seems to be an adaptive device to protect the fish from contact with the rough surface of the crinoid host.     

Effects of UV-B radiation on the gills of Catla catla during early development

Scanning electron microscopic (SEM) study of gills of Catla catla catla (17-day-old) exposed to UV-B radiation (145?µW?cm^?2 at the water surface) for three different exposure times: 5, 10 and 15?min was conducted. Fish without UV-B exposure served as control. UV-B radiation damaged both gill filaments and lamellae. The intensity of damage was minimal in 5?min exposed fish, followed by 10?min exposed fish and maximal in 15?min. The gill epithelium was severely damaged in 15?min irradiated fish compared to control. Pavement cells (PVCs) were damaged and the numbers of microridges within PVCs decreased. The deep boundary of PVC was not clear. In some area of gill epithelium, PVCs were destroyed and mitochondrion-rich cells (MRCs) were exposed. The 5?min exposure reduced the number of microridges in the PVCs, but the boundary of PVCs was still visible. MRCs in the gill epithelium were not exposed in 5?min exposed fish. The damage to PVCs and subsequent exposure of MRCs in UV-B irradiated fish may hamper respiratory functions and disturb osmoregulation in catla.     

0~#柴油和流花原油对斑节对虾(Penaeus monodon)幼体的急性毒性效应

溢油污染导致的原油和燃料油入海,会对海洋生物的生长发育过程产生影响。为研究溢油污染对海洋虾类的毒性效应,以斑节对虾(Penaeus monodon)为研究对象,比较了不同浓度0#柴油和南海流花原油(LH原油)乳化液对斑节对虾不同发育阶段幼体的急性毒性效应。结果表明,3.59 mg·L~(-1)0#柴油和0.77 mg·L~(-1)LH原油乳化液可以显著降低斑节对虾无节幼体变态率(P0.05),且对无节幼体变态具有延迟效应。较之0#柴油,LH原油乳化液对斑节对虾无节幼体发育的影响更为明显。0#柴油对斑节对虾无节幼体、蚤状幼体、糠虾和仔虾的48或96小时半致死浓度(48 h/96 h-LC50)分别为0.55 mg·L~(-1)、0.42 mg·L~(-1)、0.95 mg·L~(-1)和1.09 mg·L~(-1),其对应的安全浓度分别为0.05 mg·L~(-1)、0.04 mg·L~(-1)、0.10 mg·L~(-1)和0.11 mg·L~(-1);LH原油对上述幼体的48 h/96 h-LC50则依次为0.62 mg·L~(-1)、0.51 mg·L~(-1)、1.05 mg·L~(-1)和1.42 mg·L~(-1),对应的安全浓度分别为0.06 mg·L~(-1)、0.05mg·L~(-1)、0.11 mg·L~(-1)和0.14 mg·L~(-1)。斑节对虾不同发育阶段幼体对0#柴油和LH原油的耐受力依次为:仔虾糠虾无节幼体蚤状幼体,0#柴油和LH原油乳化液对斑节对虾的毒性大小为0#柴油LH原油。上述结果为深入研究石油类污染对海洋生物的毒性效应提供了基础数据和理论依据。     

Physiology of the digestive tract of the sedentary polychaete Terebellides stroemi

The digestive tract of the sedentary polychaete Terebellides stroemi, collected from 88 m depth on the French Catalan Coast, was studied using histological, biochemical, cytological and spectrographic techniques. The ciliated oesophagus possesses a ventral pharyngeal pouch with a muscle bulb. The stomach is divided into two parts, the fore stomach is ciliated, but the hind stomach takes the place of a gizzard with a thick peritrophic membrane and a thick muscle mantle. The digestive gland enters the digestive tract at the boundary of the two stomachal areas; it is comprised of epithelial lamellae with a glandular epithelium. The gland cells contain a spherocrystal secretion with a high calcium and phosphorus content. The cells are also absorbant due to their microvillar brush border and to the storage of glycogen and lipids in the basal epithelium. A biochemical study using the Apizym System confirmed the secretion of enzymes such as phosphatases, esterases and various carbohydrases. Tryptic and chymotryptic enzymes were visualized by biochemical hydrolysis of synthetic substrates. The epithelium of the fore intestine is similar in appearance to the epithelium of the digestive gland, but consists of a single epithelial layer. Hind intestine and rectum are only excretory systems. The presence of this digestive gland does not seem to have been described elsewhere in polychaetes but is similar to the Morren's gland of some oligochaetes. The study was carried out during 1982 and 1983.     

Tissular localization of the digestive proteases in the sedentary polychaetous annelid Sabellaria alveolata

The digestive tract of Sabellaria alveolata (L.) is partitioned into 4 main regions: oesophagus, gizzard, intestine and rectum. Histoenzymologic study of the repartition of the protease activities along the digestive tract has shown that the proteases are secreted in the anterior intestine, where numerous serous gland cells are present. These cells display many histochemical and cytological characteristics similar to those of the gland cells previously described in digestive organs of other polychaetes. The role of the other regions of the digestive tract is discussed.     

A study of mucus from the solitary coral Fungia fungites (Scleractinia: Fungiidae) in relation to photobiological UV adaptation

The ultraviolet (UV)-absorbance spectrum (300 to 360 nm) of mucus obtained from Fungia fungites (L. 1758, collected in Tahiti in 1991) after being exposed to air for up to 5 min was measured, and UV-absorbing compounds were demonstrated to be present in the mucus, with a peak at 332 nm. The concentration of these UV-absorbing compounds was at a maximum in the first 2 min of secretion and decreased thereafter. Concentration was significantly related to the weight of the coral. Also, as corals were adapted to bathymetric levels of UV radiation, mucus concentration of UV-absorbing compounds decreased significantly with increasing depth.     

Water quality of the King Abdullah Canal/Jordan–impact on eutrophication and water disinfection

The King Abdullah Canal (KAC) is an artificial water conveyor serving as raw water source for drinking water supply of Amman and for irrigation purposes in the Jordan Valley. The main water sources for KAC originate from the Yarmouk River, the Mukheiba Wells, and the Peace Conveyor. Water samples were collected from December 2002 to May 2004 to investigate changes in physicochemical parameters and parameters related to eutrophication along KAC. The catchment area of KAC is highly heterogeneous in terms of topography, climate, geologic conditions, and land use, resulting in great variations in the physicochemical composition of the canal water. The Yarmouk River and the Mukheiba Wells reflect the water quality of precipitation without much dissolution of halides, whereas the Peace Conveyor shows a groundwater characteristic. Main dischargers of N and P compounds are the Yarmouk River, and dams and wadis along KAC. The concentrations in the canal are mostly above eutrophication level for N and P. Along KAC there is an increase in chlorophyll a concentration and plankton counts. The formation potentials for trihalomethanes (THMs) and for integrated organically bound halogens are determined by chlorination to evaluate the consequences of water disinfection. Due to relatively high bromide concentration mainly brominated THMs are formed.     

Impact of biochar produced from post-harvest residue on the adsorption behavior of diesel oil on loess soil

The primary objective of this study was to investigate the effect of biochar, produced from wheat residue at different temperatures, on the adsorption of diesel oil by loess soil. Kinetic and equilibrium data were processed to understand the adsorption mechanism of diesel by biochar-affected loess soil; dynamic and thermodynamic adsorption experiments were conducted to characterize this adsorption. The surface features and chemical structure of biochar, modified at varying pyrolytic temperatures, were investigated using surface scanning electron microscopy and Fourier transform infrared analysis. The kinetic data showed that the adsorption of diesel oil onto loess soil could be described by a pseudo-second-order kinetic model, with the rate-controlling step being intraparticle diffusion. However, in the presence of biochar, boundary layer control and intraparticle diffusion were both involved in the adsorption. Besides, the adsorption equilibrium data were well described by the Freundlich isothermal model. The saturated adsorption capacity weakened as temperature increased, suggesting a spontaneous exothermic process. Thermodynamic parameter analysis showed that adsorption was mainly a physical process and was enhanced by chemical adsorption. The adsorption capacity of loess soil for diesel oil was weakened with increasing pH. The biochar produced by pyrolytic wheat residue increased the adsorption behavior of petroleum pollutants in loess soil.

     

影响石油污染物挥发行为的因素

进行了4种不同石油制品在不同温度时的挥发试验,并对其挥发量与挥发时间的关系进行了模拟,试验结果表明,柴油和煤油的挥发量与挥发时间呈二次多项式关系,而90#汽油的挥发量与挥发时间呈对数关系,混合芳烃的挥发量与挥发时间呈线性关系。柴油经过不同程度的挥发后,其物理性质如粘度和比重发生了改变,其中柴油粘度随着挥发而增加,并且柴油的粘度与挥发质量分数有很好的正相关性,相关系数为0.988。     

Investigating the potential for different scooter and car exhaust emissions to cause cytotoxic and (pro-)inflammatory responses to a 3D in vitro model of the human epithelial airway

The aim of this study was to compare the cytotoxicity and the (pro-)inflammatory responses of two-stroke (direct injection and carburetor technology) and four-stroke scooter and diesel car exhaust emissions on lung cells in vitro. This was analyzed by exposing a 3D in vitro model of the epithelial airway (consisting of human bronchial epithelial cells (cell line 16HBE14o^?) combined with human whole blood monocyte-derived macrophages and dendritic cells) to physically characterized exhaust emissions. Biological endpoints of cytotoxicity (lactate dehydrogenase release), as well as pro-inflammatory cytokine (tumor necrosis factor (TNF)-α) and inflammatory chemokine (interleukin(IL)-8) stimulation were examined. Two-stroke direct injection scooter exhaust contained the highest particle number concentration and nitrogen oxides (NO _x ) concentrations and the emissions from the two-stroke carburetor scooter contained the highest hydrocarbon and lowest NO _x concentrations. The four-stroke scooter emitted the highest carbon monoxide concentration whereas the cars emitted the lowest. The combination of various technical optimizations for the two-stroke direct injection scooter (particle filter, oxidative catalyst, better oil and fuel) reduced the total emissions strongly and the TNF-α concentration significantly (p?相似文献   

紫花苜蓿在柴油污染土壤中的萌发状况

选择以柴油作为土壤污染物，以单-外源环境因子污染水平为主要调控因子，采用室内盆栽试验的方法并且以不同质量分数的柴油污染土壤，在此情况下观察不同土壤柴油污染质量分数控制下紫花苜蓿种子的萌发与生长情况。结果表明，紫花苜蓿种子发芽抑制率与土壤柴油污染质量分数呈现指数线性相关关系，并且发现苜蓿发芽之后，高质量分数柴油处理组的幼苗出现黄叶和干枯现象。文章最后从土壤内柴油和柴油在土壤-大气界面间的迁移对种子萌发的影响进行了探讨。