Effects of ghrelin on the feeding behavior of Lymantria dispar L. (Lymantriidae) caterpillars

Ghrelin is a 28-amino acid peptide which has significant effects on animal appetite, thus influencing body mass. The aim of our study was to examine the effects of ghrelin on the feeding behavior and physiology 4th instar caterpillars of the pest insect, Lymantria dispar L. Treatment of 4th instar caterpillars with four subpicomolar amounts of ghrelin had a positive influence on daily food intake, frass elimination, body mass. Also, locomotor activity increased, while stadium duration decreased in treated caterpillars. The similarity between the effects of ghrelin on caterpillar physiology and those in mammals suggests that using this model system for further studies of neuroendocrinological processes underlying feeding could lead to essential information about more complex organisms.     

Toxic effects of chlorpyrifos on morphology and acetylcholinesterase activity in the earthworm,Eisenia foetida

The acute toxicity of chlorpyrifos (O, O-diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) was determined in the earthworm, Eisenia foetida. A 48-h contact test as described by the Organization for Economic Cooperation and Development (OECD) guideline 207 was carried out. The LC(50) of chlorpyrifos was 0.063 microg/cm(2). Inhibition of acetylcholinesterase (AChE: EC 3.1.1.7) activity indicated by in vitro neurotoxic potentiality revealed competitive inhibition and altered K(m) values widely in a dose-dependent manner. The K(i) value of chlorpyrifos was 4.20 x 10(-6)M. AChE activity of LC(50)-exposed worms was 62%, 79%, 85%, and 91% inhibited at 12, 24, 36, and 48h, respectively. Scanning electron microscopic studies revealed the morphological abnormalities in the worms. The present study demonstrates a dose- and time-dependent exposure of chlorpyrifos through skin results, morphological abnormalities, and inhibition of AChE in the earthworm, E. foetida.     

Effects of the herbicides clomazone, quinclorac, and metsulfuron methyl on acetylcholinesterase activity in the silver catfish (Rhamdia quelen) (Heptapteridae)

Fingerlings of the silver catfish (Rhamdia quelen) were exposed to three herbicides widely used in rice culture in south Brazil: clomazone, quinclorac, and metsulfuron methyl. LC50 was determined and acetylcholinesterase (AChE) activity was evaluated in brain and muscle tissue of fish exposed to different herbicide concentrations after 96h (short term). The LC50 value (nominal concentration) was 7.32 mg/L for clomazone and 395 mg/L for quinclorac, but was not obtained for metsulfuron-methyl since all fingerlings survived the highest concentration of 1200 mg/L. Brain and muscle AChE activity in unexposed fish were 17.9 and 9.08 micromol/min/g protein, respectively. Clomazone significantly inhibited AChE activity in both tissues, achieving maximal inhibition of about 83% in brain and 89% in muscle tissue. In contrast, quinclorac and metsulfuron methyl caused increases in enzyme activity in the brain (98 and 179%, respectively) and inhibitions in muscle tissue (88 and 56%, respectively). This study demonstrated short-term effects of exposure to environmentally relevant concentrations of rice field herbicides on AChE activity in brain and muscle tissue of silver catfish.     

Histopathological Alterations in Gills of White Shrimp, <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis> (Boone) After Acute Exposure to Cadmium and Zinc

White shrimp, Litopenaeus vannamei, a globally important cultured prawn species, is an ideal animal for studying the impairment caused by the effects of heavy metals that are often detected in coastal areas. In this present study, we detected the acute toxicity of cadmium (Cd) and zinc (Zn) to L. vannamei. Medium lethal time (LT50) values of Cd and Zn on L. vannamei were estimated. Furthermore, we also demonstrated that acute exposure to high concentrations of Cd and Zn resulted in morphological alterations in gills of L. vannamei in this present study.     

Correlation between 96-h mortality and 24-h acetylcholinesterase inhibition in three grass shrimp larval life stages

Three life stages of larval grass shrimp were tested to determine whether acetylcholinesterase (AChE) activity expressed as 24-h sublethal effect endpoints (EC20 and EC50) could be used to predict 96-h mortality (lowest observable effect concentration (LOEC) and LC50) for shrimp exposed to three organophosphate insecticides. With regard to mortality, newly hatched larvae and 18-day-old larvae were the most sensitive in the malathion and azinphosmethyl exposures. In the chlorpyrifos exposures, newly hatched larvae and postlarvae were the most sensitive life stages. Results of the 24-h AChE inhibition tests showed that newly hatched larvae were generally more sensitive in the three organophosphate exposures. A regression analysis of the EC50's and LC50's yielded the strongest correlation with R2=0.987 (correlation coefficient=0.994 and 95% confidence intervals 0.969-0.999). The LOEC/EC20 relationship yielded R2=0.962. For these grass shrimp life stages and pesticides, sublethal effect endpoints could be used as a predictor of 96-h mortality.     

Effects of sodium carbonate and sodium bicarbonate on yield and characteristics of Pacific white shrimp (Litopenaeus vannamei)

Effects of sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) on yield and characteristics of Pacific white shrimp (Litopenaeus vannamei) were studied. Shrimp soaked in 2.5% NaCl containing both compounds at different levels of pH (5.5, 7, 8.5, 10 and 11.5) showed an increase in the weight gain and cooking yield and a reduced cooking loss as pH of solutions increased (p<0.05). Increases in pH and salt content in soaked shrimp muscle were obtained with increasing pH (p<0.05). Higher pH of soaking solution partially solubilized proteins in the muscle as well as carotenoproteins. pH of solutions above 8.5 led to the pronounced leaching of pigments, associated with the lowered redness of cooked shrimp. Shear force of raw and cooked shrimp continuously decreased as pH of solution increased (p<0.05). Solution containing 2.5% NaCl and 2.0% NaHCO3 (pH 8.5) was recommended for treatment of white shrimp as a promising alternative for phosphates to increase the yield and to lower cooking loss without any negative effect on sensory properties.     

Heavy metal (Pb, Co, Cd, Cr, Cu, Fe, Mn and Zn) concentrations in harvest-size white shrimp Litopenaeus vannamei tissues from aquaculture and wild source

The present research project was undertaken to determine heavy metal (Pb, Co, Cd, Cr, Cu, Fe, Mn and Zn) concentrations in intensive aquaculture and wild white shrimp tissues (muscle, shell and liver), and to inform aquatic shrimp food safety. The aquaculture samples were obtained from ten intensive farms and wild animals from one station in Zhanjiang Harbour Bay. Heavy metal concentrations (mg kg⁻¹, dry weight; means ± S.D.) in aquaculture white shrimp muscle, shell and liver tissues were, respectively: Cr - 20.86 ± 5.27, 28.70 ± 8.34 and 18.91 ± 5.50, Cu - 24.26 ± 8.36, 30.86 ± 9.84 and 126.42 ± 90.9, Fe - 61.35 ± 30.76, 55.07 ± 17.72 and 124.04 ± 56.15, Mn - 5.33 ± 2.5, 10.72 ± 4.34 and 8.79 ± 5.29, Zn - 171.56 ± 118.74, 51.84 ± 10.94 and 111.74 ± 84.67. Cadmium was observed only in liver tissue at 3.30 ± 1.29 mg kg⁻¹. Lead could not be detected, and cobalt was detected only in wild shrimp liver tissue. Chromium and manganese mean concentrations in shell tissue were significantly higher than levels in muscle tissue (P < 0.05), but the zinc mean concentration was significantly lower than noted in muscle tissue (P < 0.05). Copper and iron mean concentrations in liver tissue were significantly higher than those in muscle or shell tissues (P < 0.05). Overall, only chromium in white shrimp tissue was the primary risk for human health.     

产前互动式培训对母乳喂养率及喂养技巧的影响

目的:探讨产前互动式培训与母乳喂养率及喂养技巧的关系。方法:将参加产前互动式培训的100名健康足月妊娠初产妇设为观察组,未参加产前互动式培训的100名同期健康初产妇设为对照组,两组产妇均接受产后个性化哺乳知识教育,观察两组产妇产后新生儿喂养技巧掌握情况和母乳喂养成功率的差异。结果:观察组产妇与对照组产妇对母乳喂养技巧正确掌握情况差异有统计学意义(P<0.05),同时观察组与对照组母乳喂养率分别为95%和67%,差异有统计学意义(P<0.05)。结论:产前互动式培训和住院个性化宣教能有效提高产妇母乳喂养技巧的掌握和母乳喂养成功率。     

Toxicokinetics and biotransformation of p-nitrophenol in white sturgeon (Acipenser transmontanus)

White sturgeon (Acipencer transmontanus) were exposed to 7.2 microM (1.0 ppm) 14C-labeled p-nitrophenol (PNP) in brackish water for 24 h and then allowed to depurate in clean brackish water for another 24h. Absorption, conditional uptake clearance, and conditional elimination rate constants were 0.08+/-0.04 h(-1), 8.1+/-3.6 mL g(-1) h(-1), and 0.46+/-0.21 h(-1), respectively. A whole-organism total concentration factor of 18.7+/-2.6 was determined from equilibrium tissue and water concentrations. Sturgeon depurated 89.4% of absorbed PNP within 24h, of which 53.0+/-8.3% was unmetabolized parent compound, 9.6+/-3.6% was p-nitrophenyl-beta-d-glucuronide, and 39.1+/-8.3% was p-nitrophenylsulfate.     

Effects of temperature and oxygen concentration in sediment toxicity testing

Joint effects of temperature and oxygen concentrations for the results of sediment toxicity tests were studied at 10 and 20 °C with 40% and 80% dissolved oxygen (DO) saturation. Growth, feeding rate, and reproduction of Lumbriculus variegatus (Oligochaete) and growth, emergence, and survival of Chironomus riparius (Diptera) were tested in a polluted and in a reference sediment. Both the feeding of L. variegatus and the emergence of C. riparius were significantly retarded at low temperature. Additionally, differences in the sex ratio of the emerged adults of C. riparius were observed. The oxygen concentration alone did not have any significant effect on the endpoints, but significant combined effects of polluted sediment and low DO were observed on the biomass of L. variegatus. The standard sediment toxicity tests might offer only limited data for risk assessment of contaminated sediments at sites where the actual conditions largely differ from the laboratory conditions.     

Use of the multispecies freshwater biomonitor to assess behavioral changes of Corophium volutator (Pallas, 1766) (Crustacea, Amphipoda) in response to toxicant exposure in sediment

Automated sediment toxicity testing and biomonitoring has grown rapidly. This study tested the suitability of the marine amphipod Corophium volutator (Pallas, 1766) for sediment biomonitoring using the Multispecies Freshwater Biomonitor (MFB). Two experiments were undertaken to (1) characterize individual behaviors of C. volutator using the MFB and (2) examine behavioral changes in response to sediment spiked with the pesticide Bioban. Four behaviors were visually identified (walking, swimming, grooming and falling) and characterized in the MFB as different patterns of locomotor activity (0-2 Hz range). Ventilation was not visually observed but was detected by the MFB (2-8 Hz). No clear diel activity patterns were detected. The MFB detected an overall increase in C. volutator locomotor activity after Bioban addition to the sediments (56, 100, 121 mg kg(-1)). C. volutator was more active (both locomotion and ventilation) in the water column than the spiked sediment. C. volutator appears a sensitive and appropriate species for behavioral sediment toxicity assessment and biomonitoring.     

Bioaccumulation and toxicity of sediment associated herbicides (ioxynil, pendimethalin, and bentazone) in Lumbriculus variegatus (Oligochaeta) and Chironomus riparius (Insecta)

The benthic macroinvertebrates Lumbriculus variegatus and Chironomus riparius were used in toxicity and bioaccumulation tests to determine the toxic concentrations and accumulation potential of sediment associated herbicides. The tested chemicals were ioxynil, bentazone, and pendimethalin. The bioaccumulation tests with L. variegatus were performed in four different sediments, each having different characteristics. Water-only LC₅₀ tests were performed with both L. variegatus and C. riparius. A sublethal effect of model compounds in sediments was assessed by a C. riparius larvae growth-inhibition test. Of the model compounds, ioxynil appeared to be the most toxic, with LC₅₀ values 1.79 and 2.79 mg L⁻¹ for L. variegatus and C. riparius, respectively. The LC₅₀ water concentrations for bentazone were 79.11 and 62.31 mg L⁻¹ for L. variegatus and C. riparius, respectively. Similarly, ioxynil revealed the highest bioaccumulation potential in bioaccumulation tests. The most important characters affecting chemical fate in the sediment seemed to be the organic matter content and the particle size fraction. The sediments with low organic material and coarse particle size consistently showed high bioaccumulation potential and vice versa. In C. riparius growth tests bentazone had a statistically significant effect on larval growth at sediment concentrations of 1160 and 4650 mg kg⁻¹ (P<0.05). It is noteworthy that standard deviations tend to be greater at high chemical concentrations, which addresses the fact that part of the individuals started to suffer. Ioxynil had an effect on the larval growth in other test sediment at the highest concentration (15.46 mg kg⁻¹ dw), in which head capsule length correlated with larval weight, decreasing toward higher exposure concentrations. The current results show the importance of sediment organic matter as a binding site of xenobiotics.     

Use of two biomarkers (CYP450 and acetylcholinesterase) in zebra mussel for the biomonitoring of Lake Maggiore (northern Italy)

The use of zebra mussel Dreissena polymorpha as a bioaccumulator for lipophilic compounds is nowadays standardized, but its employment in early warning systems by the biomarker approach is much less frequent. One of the main problems with the biomarker approach is due to natural variation of abiotic factors such as temperature that influence the activity of several enzymes. In this study, we investigated the influence of this environmental parameter on the activities of two different biomarkers: acetylcholinesterase (AChE) (inhibited by organophosphorus compounds) and CYP450 (inversely influenced by planar compounds and heavy metals). We used these two biomarkers to evaluate the environmental pollution of Lake Maggiore (northern Italy). Results showed a strong AChE inhibition in mussel specimens collected in some sampling sites of the lake, indicating heavy pollution by neurotoxic compounds. We also found a twofold effect on CYP450 activity, probably due to the activating effect of planar compounds and the inhibiting effect of trace metals.     

Effects of dietary Cd and Cu on feeding and growth rates of the landsnail Helix engaddensis

Effects of dietary cadmium and copper on feeding and growth rates of adult Helix engaddensis snails were studied for a 1-month period. The concentrations of cadmium were 0, 50, 100, 200, 400, and 800 microg Cd/g dry food, while those of copper were 0, 4, 20, 100, 500, and 2500 microg Cu/g dry food. Both metals inhibited feeding and growth rates significantly after 1 week and 3 weeks of exposure to Cd and Cu, respectively. Inhibition caused by Cd was found to be irreversible, which indicates toxicity, while that of Cu was reversible, indicating starvation because snails identified and refused to consume contaminated food. After 4 weeks of exposure, the NOEC of Cd was 50 microg/g and the LOEC was 100 microg/g, while those for Cu were 20 and 100 microg/g, respectively. EC50,75,90,100 (growth and feeding) values were calculated, and indicated that H. engaddensis snails are suitable for short-term toxicity bioassays.     

Effects of salinity on biomarker responses in Crassostrea rhizophorae (Mollusca, Bivalvia) exposed to diesel oil

Crassostrea rhizophorae is a euryhaline oyster that inhabits mangrove areas, which are widely distributed along the Brazilian coast. The aim of this study was to investigate the effects of salinity (9, 15, 25, and 35ppt) on the activities of glutathione S-transferase (GST), glucose 6-phosphate dehydrogenase (G6PDH), catalase (CAT), and acetylcholinesterase (AChE) in the digestive gland of this species after exposure to diesel oil for 7 days at nominal concentrations of 0.01, 0.1, and 1mlL(-1) and after depuration for 24h and 7 days. GST activity increased in a diesel oil concentration-dependent manner at salinities 25 and 15ppt and remained slightly elevated even after depuration periods of 24h and 7 days. No changes were observed in the activities of G6PDH, CAT, and AChE in the oysters exposed to diesel and depurated. Based on these results, GST activity in the digestive gland of C. rhizophorae might be used as a biomarker of exposure to diesel oil in sites where the salinity is between 15 and 25ppt, values usually observed in mangrove ecosystems.     

嗜肺性军团杆菌培养基(BALM)的研究

蓝藻培养液能促进嗜肺性军团杆菌的生长,将此培养滤液适量加入参照硝酸铁培养基配方用国产试剂自制的基础培养基(LM)中,制成蓝藻培养基(BALM)。嗜肺性军团杆菌第6血清型标准株在BALM上形成菌落的能力优于BCYE;第1血清型标准株在两种培养基上的菌落形成能力较接近。从临床标本中分离NANJ-1株的结果表明,该菌株在BALM上的生长时间、菌落大小优于BCYE和其他几种培养基。     

Influence of Copper on the Feeding Rate, Growth and Reproduction of the Golden Apple Snail, Pomacea canaliculata Lamarck

The influence of copper on feeding rate, growth, and reproduction of Pomacea canaliculata Lamarck was evaluated. Ten days of exposure to copper of relatively high concentration (67.5 μg/L) reduced the snails’ feeding rate and retarded their growth. Exposure to 20 μg/L after 36 days increased feeding rate to 28%. After 20 days of exposure at 30 μg/L, snail’s growth was significant but thereafter declined. Growth of all snails including control was negligible by day 50 when snails were in the reproductive state. Copper did not affect reproduction.     

Toxicity of azodrin on the morphology and acetylcholinesterase activity of the earthworm Eisenia foetida

The acute toxicity of azodrin (monocrotophos, an organophosphorus insecticide) was determined on a soil organism, Eisenia foetida. The median lethal concentrations (LC50) were derived from a 48-h paper contact test and from artificial soil tests. The LC50 of azodrin in the paper contact test was 0.46 +/- 0.1 microg cm(-2) (23 +/- 6 mg L(-1)) and those in the 7- and 14-day artificial soil tests were 171 +/- 21 and 132 +/- 20 mg kg(-1), respectively. The neurotoxic potentiality of azodrin was assessed by using a marker enzyme, acetylcholinesterase (AChE; EC 3.1.1.7) in both in vitro and in vivo experiments. The progressive signs of morphological destruction are correlated with percentage inhibition of AChE in the in vivo experiments. The kinetics of AChE activity in the presence and absence of azodrin indicated that the toxicant is competitive in nature. This study demonstrated that azodrin causes concentration-dependent changes in the morphology and AChE activity of the earthworm E. foetida.     

Contamination levels of lead, cadmium and mercury in imported and domestic lobsters and large crab species consumed in France: Differences between white and brown meat

Lead, cadmium and total mercury contents have been determined by atomic absorption spectrometry in white and brown meat of 108 batches of crustaceans (lobsters, spider crabs, common crabs, swimming crabs and king crabs) collected in France between April and December 2009. With mean levels of 0.041, 0.132 and 0.128 mg kg⁻¹ for Pb, Cd and Hg, respectively, concentrations in white meat were systematically below the European legislation maximum level of 0.50 mg kg⁻¹. Cd concentration in the brown meat of common crabs (mean concentration: 11.8 mg kg⁻¹ and maximum of 14.3 mg kg⁻¹) was well above the observed levels for white meat. The consumption of one whole common crab of 1 kg (about 120 g of white and brown meat) would not contribute significantly to the Pb and Hg provisional tolerable weekly intake (PTWI) for adults, but the ingested Cd would greatly exceed the TWI of 2.5 μg kg⁻¹ body weight, which may be a health issue for consumers of brown meat. Therefore, we recommend moderate brown meat consumption.     

Detection of rabbit haemorrhagic disease virus (RHDV) in nonspecific vertebrate hosts sympatric to the European wild rabbit (Oryctolagus cuniculus)

Since its detection in China in 1984, rabbit haemorrhagic disease (RHD) has been the subject of numerous studies. Yet, the evolutionary origin of rabbit haemorrhagic disease virus (RHDV) is still under debate. For example, some aspects related to the epidemiology of the disease are still unknown, such as where the virus is hosted between RHD outbreaks. To detect the presence of RHDV in rabbit-sympatric micromammals, 51 rodents (29 Mus spretus and 22 Apodemus sylvaticus) and 31 rabbits (Oryctolagus cuniculus) from the same location in central Spain were analyzed. In those samples in which the virus was detected, a fragment of the VP60 protein gene from the RHDV capsid was sequenced and the phylogenetic relationships between them and other strains of RHDV in the Iberian Peninsula were analyzed. In total, five viral strains were identified in A. sylvaticus, M. spretus and O. cuniculus. All strains were found to be well supported within the clade of RHDV found in rabbits in the Iberian Peninsula. Moreover, one of the strains was found in all three species under study, which suggests the capability of RHDV to infect other mammals apart from the rabbit which have not yet been investigated. The transmission of the virus is discussed as well as its ecoepidemiological implications.