Carbaryl-induced alterations in biochemical metabolism of the prawn,Macrobrachium malcolmsonii

The present study was performed to investigate the toxic impact of carbaryl on biochemical metabolism in the hemolymph, brain, hepatopancreas, gills and muscle of intermoult juveniles of the economically important prawn, Macrobrachium malcolmsonii. The concentration of glutathione S-transferase (GST) was found to be higher in test prawns when compared with controls. This suggests that a mechanism of detoxification was in operation to neutralise carbaryl toxicity. However, the toxic effect of carbaryl was not fully neutralised, and hence, alterations were recorded in basic biochemical metabolism of test prawns. The concentration of acetylcholinestrase (AchE) was found to be lower in test prawns than that of controls. Carbaryl toxicity resulted in utilisation of major biochemical constituents, such as total carbohydrate, glycogen, protein and lipid to generate required energy as an attempt to withstand the toxic stress. Glycogenolysis resulted in elevation of total free sugar level in the hemolymph of test prawns. While proteolysis led to elevation of total free amino acid level in test prawns. The content of total lipid have also been found lower in test prawns than that of controls. This suggests that carbaryl toxicity resulted in severe energy crises in test prawns. In the present study, toxic effects of carbaryl impair basic metabolic functions and hence pose a threat to the life of M. malcolmsonii.     

Sub-lethal impact of carbaryl on food utilization in the freshwater prawn Macrobrachium malcolmsonii

This study determines the toxic effect of carbaryl (Sevin50% W.P) on the food utilization parameters in intermoult juveniles of the prawn, Macrobrachium malcolmsonii. The prawns (4.5-5.0 cm in length and 1.0-1.25 g wet wt.) were exposed to three sub-lethal concentrations of carbaryl (5.15, 7.73 and 15.47 microgl-1) for duration of 40 days. The toxic medium was renewed daily. The prawns were fed ad libitum with known energy quantity of boiled goat liver on daily basis. The overall wet weight gain was calculated. The energy lost through unconsumed food (15-60%), faeces (15-109%), ammonia excretion (9-27%) and moults (13-26%) of the prawns were calculated. The feeding rate, the rate and efficiency of absorption, the metabolic and food conversion rates and the gross and net food conversions efficiencies were found to be significantly declined (p<0.05) in test prawns when compared to that of the control. The energy lost through faeces, ammonia excretion and exuvia was found to be significantly elevated (p<0.05) in test prawns than that of the control. The effectof carbaryl on the bioenergetics parameters was severe in the highest sub-lethal concentration, less in the intermediate concentration and least in the lowest sub-lethal concentration. The results indicated that decrease in feeding, absorption, metabolism and food conversion are interdependent and toxicity of carbaryl diverting energy from production to maintenance pathways, which ultimately resulting in declined growth of M. malcolmsonii.     

Effects of Hg and Cu on hemocytes-mediated functions in the prawn,Macrobrachium malcolmsonii

Sublethal effects of Hg (9.6, 14.5 and 24.1 microg/l) and Cu (60.5, 90.8 and 150.5 microg/l) on the hemocytes-mediated functions in the juveniles of the economically important freshwater prawns, Macrobrachium malcolmsonii were investigated. The population of total hemocytes, percentile phagocytosis and superoxide anion production were found to be increased in test prawns exposed to the lowest sublethal concentration of these two metals in comparison to controls. This indicates the fact that a mechanism of host-defence was in an active state to encounter metal toxicity. The total hemocytes population, percentile phagocytosis and superoxide anion production were found to be decreased in test prawns exposed to intermediate as well as the highest sublethal concentrations of Hg and Cu when compared with controls. This suggests that high concentrations of both Hg and Cu have inhibitory effects on the immune functions of the hemocytes in the prawn, M. malcolmsonii.     

Hepato and nephrotoxicity in rat exposed to endosulfan

The indiscriminate and injudicious use of pesticides particularly endosulfan in agriculture and animal husbandry practices has considerably increased the risk of human health hazard. The present work was therefore undertaken to evaluate the toxic effect of endosulfan on the vital organs viz. liver and kidney of rat. Oral administration of endosulfan at the dose level of 10 mg/kg b.wt./day for two and four weeks showed toxic interference with the biochemistry and histology of rat liver and kidney. The biochemical parameters viz. Aspartate amino transferase, alanine amino transferase, acid phosphatase, alkaline phosphatase, bilirubin urea and creatinine were increased which clearly showed the hepato and nephrotoxic effect of endosulfan. Histopathologically the size of liver was increased, sinusoidal dilation, pyknotic nuclei, cytoplasmic degranulation and various nuclear aberrations were observed. Similarly pathological alterations viz. chronic glomerulonephritis, glomerulosclerosis, odenoma and glomerulus deposits were observed in the kidney.     

Effect of hatching time on larval mortality and survival of the prawn Macrobrachium idae

The prawn Macrobrachium idae Heller carries 40 to 160 eggs depending upon the body size of the mother animal. After incubation, 63, 35 and 2% eggs are hatched on the first, second and third hatching nights, respectively. Mean dry weight of a single larva relased on the first night is 420 g (equivalent to 2.86 cal). Larvae released on the second or third hatching nights weighed 380 g (=2.56 cal) or 308 g (=2.02 cal). The total reserve yolk-energy available in a larva hatched on the first night is 1 cal. There is a definite shift from protein to fat metabolism as hatching is delayed. Oxygen consumption of developing eggs awaiting release on the first or second hatching night is 1.9 l/mg dry weight/h. In comparison to larvae released on the first night, those released on the second night exhibit 2% increase in total body-length and 2.4 or 14.3% decrease in the lengths of the 6th abdominal segment or the orbit. Larvae released on the first, second or third hatching nights, on exposure to starvation stress, survive for 3.8, 2.3 or 1.5 days. The swimming speed of larvae released on the first or second night is 1.0 or 0.6 cm/sec. Larvae released on the subsequent hatching nights committed nearly 2 times greater number of mistakes per cm distance in the horizontal plane. Since hatching of all developing eggs simultaneously on the first hatching night is possible by means of artificial technique(s), it is possible to improve survival rate of decapod larvae.     

Effect of Pseudomonas aeruginosa on the giant freshwater prawn, Macrobrachium rosenbergii--histopathological and electron microscopic study

The giant freshwater prawn Macrobrachium rosenbergii was injected with an inoculum containing LD, 96 hr dose of 10' Pseudomonas aeruginosa (MTCC 1688) to determine the histopathological effects in vivo. The comparison of tissues of both the control and the bacterial endotoxin treated prawns after 96 hr revealed significant degenerative changes in treated prawns. Both light microscopic and electron microscopic observations revealed the infiltration of the tissues of Pseudomonas sp in the muscular and hepatopancreatic tissues of prawn. The muscular tissue changes in the myofibrillar arrangement with blockage at the gap junctions and necrotic lesions were observed. The hepatopancreatic cells were vacuolated with hypertrophied nucleus. Atrophy of hepatopancreatic tubules was conspicuous. The pathogenicity of Pseudomonas aeruginosa is attributed to its infiltration and multiplication inside the tissues and the consequent release of extra-cellular enzymes for its metabolism. The degeneration of host tissues is also attributed to the latter.     

The role of soil humic and fulvic acid in the sorption of endosulfan (alpha and beta)

The sorption behaviour of alpha- and beta-endosulfan in soil organic matter was investigated using standard soil humic acid (HA) and soil fulvic acid (FA) with a modified solubility enhancement method and a dialysis bag technique. For HA, all the experiments were conducted at an ionic strength of 0.001 mol/L, in both the presence and absence of calcium and at an ionic strength of 0.01 mol/L. For FA, the experiments were conducted at two ionic strengths: 0.001 mol/L (with calcium) and 0.01 mol/L. This study is the first to describe the striking differences in the sorption behaviours of the two stereoisomers of endosulfan in HA and in FA. The sorption coefficients of alpha-endosulfan in HA and FA were significantly higher than those of beta-endosulfan. Beta-endosulfan has comparable sorption coefficients (1.5–5.4 L/g) in HA and in FA. Ionic strength and the presence of calcium have no significant effect on the sorption of beta-endosulfan in HA. However, calcium can significantly (p=0.01) enhance the solubility of alpha-endosulfan in HA. Changes in ionic strength by one order of magnitude also affect the solubility of alpha-endosulfan in HA. The sorption coefficients of alpha-endosulfan in HA (10–36 L/g) were greater than those in FA (9–14 L/g). The chirality of the alpha-isomer was hypothesised to be the primary reason behind its higher sorption in soil organic matter relative to the beta-isomer. In the presence of dissolved HA and FA found in natural soil environments, solubility of endosulfan can be increased by five times than the aqueous solubility of endosulfan without HA and FA.     

Effect of Pseudomonas aeruginosa (MTCC 1688) on the tissue phosphatases activity on Macrobrachium rosenbergii (De Man)

A time course study on the endotoxin toxicity of the gram negative bacteria, Pseudomonas aeruginosa MTCC 1688 on the tissue phosphatases activity on the giant freshwater prawn, Macrobrachium rosenbergii was conducted. The results revealed marked elevation of both acid and alkaline phosphatase activity in the haemolymph and body muscle. The hepatopancreas showed reduced phosphatase activity compared to control. The enzymes, being non-specific in action and particularly the acid phosphatase being of lysosomal origin, their increase in muscle and haemolymph has pathogenic significance in the inoculum treated prawns.     

Toxic response of endosulfan to breeding and non-breeding female mosquitofish

To investigate if toxic effects by endosulfan, a commonly used insecticide, are dependent on the breeding condition of an organism, both breeding and non-breeding female western mosquitofish, Gambusia affinis, were exposed to 0.1, 0.5, 1 ppb of endosulfan. After a 5-week exposure period, we examined physical factors such as ovary weight and anal fin length in fish of both reproductive conditions and the size of thyroid follicles in non-breeders. Breeding female fish exposed to endosulfan did not show any significant changes in physical factors, but non-breeding females exposed to endosulfan had a significantly greater ratio of anal fin/ body length and larger thyroid follicles than did control females. These results demonstrate that the response to exposure to environmental contaminants may be dependent upon seasonal reproductive condition.     

Growth inhibition and DNA damage in the earthworm (Eisenia fetida) exposed to perfluorooctane sulphonate and perfluorooctanoic acid

An artificial soil method was applied to study the effects of perfluorooctane sulphonate (PFOS) and perfluorooctanoic acid (PFOA) on earthworms (Eisenia fetida). Survival, growth inhibition and damage to DNA of earthworms were detected after 14 d acute exposure. The 14 d-LC₅₀ of PFOS and PFOA was 478.0?mg·kg^?1 dw and 759.6?mg·kg^?1 dw, respectively, indicating that they were of low toxicity. Both PFOS and PFOA could significantly inhibit the growth of earthworms after 14 d exposure, and growth inhibition rates increased with the greater concentrations of PFOS or PFOA, showing a dose–response relationship (PFOS: r?=?0.951, P r?=?0.962, P?P?50 of PFOS was lower than that of PFOA, the growth inhibition rate of earthworm exposed to PFOS was higher than that exposed to PFOA at the same concentration level, and the median values of TL, CL and OTM in PFOS treatments were also higher than those in PFOA treatments. In conclusion, both these fluorine compounds were moderately toxic to earthworms, but the PFOS effect was greater than that of PFOA.     

Fatty acid composition of organs and tissues of the tiger prawn Penaeus esculentus during the moulting cycle and during starvation

The fatty acids (FA) in neutral lipid (NL) and polar lipid (PL) of digestive gland, muscle and integument of Penaeus esculentus Haswell were analysed and compared during the moulting cycle and during starvation. The prawns were collected from Moreton Bay, Queensland, Australia, by trawling during 1985–1987, and were fed with a standard semi-purified diet. Compared with a natural diet, the artificial diet had much higher levels of 18:1n-9 and 18:2n-6, but only trace amounts of 20:4n-6, but there was no evidence of dietary imbalance. The fatty acid composition (percentage of total lipid) of the digestive gland changed markedly during the moulting cycle and during starvation, but the small changes observed in both muscle and integument suggested that these tissues maintained their composition under both conditions. When the fatty acids were calculated as absolute amounts, muscle composition, as well as that of the digestive gland, changed significantly. In the digestive gland, saturated FA (SFA), monounsaturated FA (MUFA), diunsaturated FA (DUFA) and polyunsaturated FA (PUFA) all increased up to the middle of the moulting cycle and then declined; with starvation all groups decreased. In muscle, SFA, MUFA and DUFA all increased during the moulting cycle; starvation caused SFA, MUFA and PUFA to decrease, whereas DUFA did not vary. Starvation caused both 18:2n-6 (linoleic) and 18:3n-3 (linolenic) in the digestive gland to reach or almost reach zero. The other essential PUFA, 20:4n-6 (arachidonic), 20:5n-3 (eicosapentaenoic) and 22:6n-3 (docosahexaenoic), decreased during the moulting cycle, but during starvation 20:4n-6 did not decrease as much. In muscle, the levels of 18:2n-6 and 18:3n-3 increased, while 20:4n-6, 20:5n-3 and 22:6n-3 remained approximately constant during the moulting cycle. Starvation reduced 20:5n-3 and 22:6n-3 to about 60%. The data suggest that levels of 18:3n-3, 20:4n-6, 20:5n-3 and 22:6n-3 are regulated, and that 20:4n-6 can be synthesised from 18:2n-6. There is no clear evidence that 20:5n-3 and 22:6n-3 are essential in P. esculentus, but tissue catabolism of cell membranes during starvation may have provided sufficient amounts for maintenance.     

酸沉降影响下重庆马尾松林的健康监测及调控技术研究

酸沉降影响下重庆马尾松(Pinus massoniana)林的衰退一直受到研究者的重视,并取得一定成果,但森林健康监测和调控技术等方面的研究还很少。以重庆铁山坪马尾松纯林为研究对象,采用欧洲叶量损失率的划分标准,选择叶量损失率为0～20%、20%～40%、40%～60%和60%～99%的优势木,分析其树冠下的土壤化学性质及针叶元素含量;采用随机区组设计,设立在土壤表面撒施石灰石粉0(不撒施石灰石粉,对照)、1、2、3和4t·hm-25个处理,探讨不同石灰石粉剂量处理对优势木针叶元素含量和生长的影响。结果表明:不同叶量损失率的马尾松优势木树冠下的土壤化学性质基本相似,0～60cm土层的pH平均值在3.59～3.80,盐基饱和度平均值低于10%,土壤严重酸化,随叶量损失率的增加,一年生针叶内K、Na、Ca、Mg、Al、P、S、N等元素含量并无明显差异。针叶内P缺乏是营养限制因子。撒施石灰石粉165d后,1、2、3t·hm-2处理的优势木一年生针叶中P、Mg含量增加,增幅以2t·hm-2处理最高,比对照分别增加30.26%和12.65%;所有撒施石灰石粉处理的N含量增加,Ca含量有增有减,变化规律不明显。撒施石灰石粉一年后,各处理优势木的树高和胸径生长量增加,针叶损失率下降,主轴顶梢长度和一年生针叶长度增加。短期内从一年生针叶中P、Mg含量及林木生长和健康情况变化综合来看,石灰石粉一次撒施量以2t·hm-2效果最佳。     

Feed utilisation and growth in juveniles of Labeo rohita under the stress of endosulfan

The objective of the present study is to evaluate the nutrition and growth of Labeo rohita under the sublethal stress of endosulfan. It has been observed that the feed utilisation and growth were inferior in the fish under the stress of the toxicant. It was more so in the test fish under the influence of higher sublethal concentration. The food conversion ratio was higher suggesting that the nutrients are wasted.     

Phylogenetic diversity of Archaea in prawn farm sediment

The structure and diversity of the Archaea collected from prawn farm sediment were investigated for the first time. A partial 16S ribosomal DNA library was constructed with Archaea-specific primers. Subsequently, 80 randomly selected archaeal clones from the library were analyzed by restriction fragment length polymorphism (RFLP), and resulted in 50 different RFLP patterns. Sequence analysis of representatives from each unique RFLP type revealed high diversity in the archaeal populations, and the majority of archaeal clones were either members of novel lineages or most closely related to uncultured clones. In the phylogenetic analysis, the archaeal clones could be grouped into discrete phylogenetic lineages within the two kingdoms Crenarchaeota and Euryarchaeota. Euryarchaeota dominated in our archaeal library, with up to 72.2% of the total clones, and Crenarchaeota represented 27.8%. Of all the Euryarchaeota clones, three clones (5.6%) were affiliated with Methanosarcinales, four clones (7.4%) were related to Methanomicrobiales, three clones (5.6%) were related to Halobacterium (with 93% similarity), and the remaining clones (81.5%) were related to those uncultured Euryarchaeota in the aquatic sediment ecosystem. None of the crenarchaeal clones were associated with any known cultured lineages. The selective dispersal of the archaeal population indicates that their ecological niches are associated with environmental characteristics. Novel phylotypes of Archaea would expand our understanding of the genetic diversity of Archaea in aquatic sediment systems and would be significant in the phylogenetic study of Archaea.Communicated by O. Kinne, Oldendorf/Luhe     

Gene expression profiling of human liver carcinoma (HepG2) cells exposed to the marine toxin okadaic acid

The marine toxin, okadaic acid (OA) is produced by dinoflagellates of the genera Prorocentrum and Dinophysis and is the causative agent of the syndrome known as diarrheic shellfish poisoning. In addition, OA acts as both a tumor promoter, attributed to OA-induced inhibition of protein phosphatases as well as an inducer of apoptosis. To better understand the potentially divergent toxicological profile of OA, the concentration-dependent cytotoxicity and alterations in gene expression on the human liver tumor cell line HepG2 upon OA exposure were determined using RNA microarrays, DNA fragmentation, and cell proliferation assays as well as determinations of cell detachment and cell death in different concentrations of OA. mRNA expression was quantified for approximately 15,000 genes. Cell attachment and proliferation were both negatively correlated with OA concentration. Detached cells displayed necrotic DNA signatures but apoptosis also was broadly observed. Data suggest that OA has a concentration dependent effect on cell cycle, which might explain the divergent effects that at low concentration OA stimulates genes involved in the cell cycle and at high concentrations it stimulates apoptosis.     

Oxidative stress in the freshwater cyprinid crucian carp (Carassius carassius L.) upon chronic exposure to endosulfan

Oxidative stress and antioxidant responses of crucian carp, upon chronic exposure to endosulfan, were evaluated in vivo. The lethal concentration (LC_50–96?h) was 70 μg L^?1; on its basis, the fish were exposed to endosulfan at 20, 35, and 50 μg L^?1 and autopsy was done on days 1, 2, 3, 4, 7, 14, 21, 28, and 35. Lipid peroxidation was induced in a concentration-dependent manner, being highest at 50 μg L^?1 (3/4 LC_{50–96 h}, sub-lethal concentration-I, SL-I) on day 4 (720% versus control), followed in its extent (490%) at 30 μg L^?1 (1/2 LC_{50–96 h}, sub-lethal concentration-II, SL-II) on day 7 and lowest (260%) at 10 μg L^?1 (1/4 LC_{50–96 h}, sub-lethal concentration-III, SL-III) on day 14. Glutathione showed a concentration- and time-dependent elevation in the initial phase, with highest level on day 4 (180%) at SL-I, but showed significant reduction in all test concentrations from day 21 of post-exposure. Superoxide dismutase was decreased significantly throughout the study, with highest reduction (63%) on day 4 at SL-I; catalase increased in all test concentrations up to day 14 but showed a significant decrease from the day 28 of post-exposure. The potential role of these parameters as indicators of pesticide pollution in aquatic systems is discussed.     

Setal development,moult-staging and ecdysis in the banana prawn Penaeus merguiensis

Specimens of juvenile Penaeus merguiensis de Man (1888) were captured by seine netting from the shores of Cleveland Bay, Townsville, Queensland Australia between February 1980 and November 1981. Accurate determination of moult cycle stage can be achieved rapidly by microsopical examination of setal development in an excised whole pleopod. Four major stages and 5 substages within premoult were clearly defined. The rate of setogenesis varies along the length of a pleopod, precluding the examination of only one specific location on the pleopod for accurate moult cycle staging. The process of ecdysis lasts for no more than 40 s.     

Structure and function of the chelate pereiopods of the banana prawn Penaeus merguiensis

Penaeus merguiensis de Man systematically searches the substratum and removes small particles of food from it using the small chelae of the first three pairs of pereiopods. One or more chelae are used to transfer food particles to the mouth. The propus and dactylus of these limbs bear numerous setae arranged in discrete groups along the length of the segments. The tip of each seta is elaborately sculptured and has a large sub-terminal pore. It is probable that these are chemosensory organs responsible for discriminating edible from non-edible material. Proximal to almost every setal group is a much-branched seta (rarely two) which probably measures the depth to which the chela has been inserted into the substratum. At the articulation of the propus and carpus of the first pereiopod are three groups of differently sculptured setae, whose function is to clean the other chelate pereiopods. An elaborate system of pegs and a ridge on the apposable fringes of the chelae might be a mechano-receptive device with a particle size discriminating function. The ridges merge into opposable terminal denticulate pads whose function is to grasp food and other particles, which may be quite small (10 to 20 m upwards).