Sublethal effects of a new antifouling candidate on lumpfish (Cyclopterus lumpus L.) and Atlantic cod (Gadus morhua L.) larvae

Abstract

Sublethal effects of medetomidine, a new generation antifouling compound, on lumpfish (Cyclopterus lumpus L.) and cod (Gadus morhua L.) larvae were examined. The effects on respiration rate and on colour adaptation of newly hatched larvae were assessed after 24–96 h exposure. Exposure of lumpfish larvae to the experimental concentrations resulted in a significant decrease in respiration rate (Lowest Observed Effect Concentration (LOEC) = 5–10 nM) and in the percentage of dark larvae (LOEC = 4 nM). However, no effects on respiration rate of cod larvae were detected. In addition to lumpfish larvae being affected at low concentrations of medetomidine, a reversibility of the effects was observed when 96 h-exposed larvae were incubated in clean seawater for 24–48 h. Considerations relating to the future commercialisation of medetomidine for antifouling purposes are discussed.     

Diseases and Injuries Associated with Mortality of Hatchery Reared Baltic Cod (Gadus morhua L.) Larvae

A cod hatching plant was established in 1992 on the island of Bornholm in the Baltic Sea in order to elucidate the possibilites for restocking of cod fry in this brackishwater system. The disease prevalence in 3 batches of hatchery-reared yolksac larvae from the Baltic cod (Gadus morhua L.) was monitored during the posthatch period. High prevalences of bacteriosis/mycosis, lordosis/scoliosis, injuries and protozoan endoparasitism were recorded. Vibrio sp. and Vibrio anguillarum serovar 04, 06, 08 in addition to nontypable strains and saprolegniaceous fungi were isolated from the larvae. The dinoflagellate-like endoparasites were located in the yolksac of the cod larvae.     

菜青虫感染蜡蚧轮枝菌后的组织病理变化

对感病菜青虫Pieris rapae组织切片的观察研究表明, 蜡蚧轮枝菌Verticillium lecanii主要通过昆虫的体壁侵染虫体。菜青虫各龄幼虫在体壁接菌12 h后,附着在虫体表面的孢子即可萌发。2～3龄幼虫,蜡蚧轮枝菌菌丝24 h就可穿透体壁进入血腔,48 h可见脂肪体等器官发生病变; 4～5龄幼虫,36 h菌丝才可穿透体壁,48 h可见虫体内有部分菌丝体。侵入虫体内的菌丝对寄生组织没有选择性。菌丝首先在入侵的血腔中生长,然后侵入脂肪体和肌肉,随菌丝在虫体内的增殖,中肠、马氏管、丝腺等相继被侵染。受侵的组织器管均发生明显的病变,如体壁分离,脂肪体变形、溶解,肌纤维排列松散,中肠上皮细胞脱落并出现许多空泡等。     

Bacterial Colonization of Cod (Gadus morhua L.) and Halibut (Hippoglossus hippoglossus) Eggs in Marine Aquaculture

Aquaculture has brought about increased interest in mass production of marine fish larvae. Problems such as poor egg quality and mass mortality of fish larvae have been prevalent. The intensive incubation techniques that often result in bacterial overgrowth on fish eggs could affect the commensal relationship between the indigenous microflora and opportunistic pathogens and subsequently hamper egg development, hatching, larval health, and ongrowth. Little information about the adherent microflora on fish eggs is available, and the present study was undertaken to describe the microbial ecology during egg development and hatching of two fish species of potential commercial importance in marine aquaculture. Attachment and development of the bacterial flora on cod (Gadus morhua L.) eggs from fertilization until hatching was studied by scanning electron microscopy. The adherent microflora on cod (G. morhua L.) and halibut (Hippoglossus hippoglossus) eggs during incubation was characterized and grouped by cluster analysis. Marked bacterial growth could be demonstrated 2 h after fertilization, and at hatching eggs were heavily overgrown. Members of the genera Pseudomonas, Alteromonas, Aeromonas, and Flavobacterium were found to dominate on the surface of both cod and halibut eggs. The filamentous bacterium Leucothrix mucor was found on eggs from both species. While growth of L. mucor on halibut eggs was sparse, cod eggs with a hairy appearance due to overgrowth by this bacterium close to hatching were frequently observed. Vibrio fischeri could be detected on cod eggs only, and pathogenic vibrios were not detected. Members of the genera Moraxella and Alcaligenes were found only on halibut eggs. Caulobacter and Seliberia spp. were observed attached to eggs dissected from cod ovaries under sterile conditions, indicating the presence of these bacteria in ovaries before spawning. Adherent strains did not demonstrate antibiotic resistance above a normal level. Attempts to regulate the egg microflora by incubation of gnotobiotic eggs with defined antibiotic-producing strains did not result in persistent protection against subsequent colonization by the microflora of the incubator.     

Surface active adrenoceptor compounds prevent the settlement of cyprid larvae of Balanus improvisus

The barnacle Balanus improvisus is the major fouling macroorganism in Swedish waters and it colonizes most man‐made surfaces submerged in the sea. New or impending legislation restricts the use of traditional, hazardous antifouling coatings based on heavy metals, mainly copper and tin. This calls for the development of new non‐toxic methods that prevent barnacle settlement. In this work several adrenoceptor compounds are shown to be very efficient in preventing the settlement of cyprid larvae of B. improvisus. The settlement rate of laboratory‐reared cyprids was studied in hydrophilised polystyrene dishes containing adrenoceptor antagonists and agonists dissolved in seawater. Two of these drugs, medetomidine and clonidine, repeatedly inhibited settlement at concentrations between 1 nM and 10 nM. In the vertebrate adrenoceptor classification system, which separates pharmacological substances according to their receptor affinity, both of these substances are classified as α₂ adrenoceptor agonists. An inhibiting effect on presyn‐aptic receptors is suggested, but the localization of the receptor effect requires futher studies. Experiments also revealed that the inhibiting effect of medetomidine was reversible. Cyprids incubated with medetomidine for 20 h attached and metamorphosed into juvenile barnacles after washing and transferrence to seawater. The antagonizing compound atipamezole reversed the effect of medetomidine. This observation supports the assumption that this substance acts at the receptor level. Studies of the surface affinity of medetomidine revealed a strong tendency to accumulate in solid/ liquid phase boundaries. This ability makes it particularly attractive as a candidate for the development of a slow‐release carrier in marine coatings. Panels coated with medetomidine in an acrylate polymer and exposed in the field reduced the recruitment of B. improvisus by 96% after 4 weeks and by 70% after 8 weeks.     

Interaction of Metarhizium anisopliae (Metsch.) Sorok., Beauveria bassiana (Bals.) Vuill. and the parasitoid Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae) with larvae of diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae)

Chemical insecticides are broadly applied to control diamondback moth, Plutella xylostella (L.). Diamondback moth is a major pest of cruciferous worldwide, and resistance of this pest to insecticide has been often reported. Thus, this research investigated the interactions among the fungi Metarhizium anisopliae (Metsch.) Sorok., Beauveria bassiana (Bals.) Vuill., and the larval-pupal parasitoid Oomyzus sokolowskii (Kurdjumov) before and after application of the fungi on DBM larvae offered to the parasitoid. The experiment was carried out at 26+/-l degreeC, 75+/- 5% RH and 12h photophase using a completely randomized design, with eight treatments with six replications each. The isolates E9 of M. anisopliae and ESALQ 447 of B. bassiana, were used at the concentration of 10(7) conidia ml(-1). The results showed that M. anisopliae and B. bassiana reduced the parasitism of P. xylostella by O. sokolowskii. Additive effects were found on the mortality of P. xylostella with the different combinations among the fungi and parasitoid, except for the treatment B. bassiana inoculated 24h before exposition of the larvae to O. sokolowskii. The isolates were more efficacious when applied after exposition of the larvae to the parasitoid. The efficiency of O. sokolowskii was negatively influenced by the presence of the fungi, mainly when the fungi were applied 24h before diamondback's larvae were exposed to the parasitoid. The association of the fungi with the parasitoid presents potential to be tested in field. The use of these natural enemies in the integrated management of P. xylostella may economically improve the cabbage productive system, especially for organic farming.     

The ontogeny of complement component C3 in Atlantic cod (Gadus morhua L.)--an immunohistochemical study

The complement system in fish is well developed and plays an important role in the immune response. Very little is known about the ontogeny of C3 in fish and no study has previously been done on the development of C3 in teleosts. In this study we have detected the presence of C3 in cod larvae from the age of 1 day post hatching (p.h.) till 57 days p.h., using immunohistochemistry. The specific primary antibodies used, were produced against the beta-chain of cod C3. Immunostaining on cod larvae sections revealed that C3 is detectable in the yolksac membrane from day 1 p.h., and in liver, brain, kidney and muscle from day 2 p.h. C3 was also detected in other organs such as eye, notochord, stomach, intestines, pancreas, heart and gills at different stages of cod larval development. These findings suggest that complement is not only important in immune defence against invading pathogens but may also play a role in the formation and generation of different organs.     

Applying weight gain in Pomacea lineata (SPIX 1824) (Mollusca: Prosobranchia) as a measure of herbicide toxicity.

Pomacea lineata, an extremely ubiquitous snail and pest to rice farmers throughout Asia, holds promise as a valuable resource for monitoring water quality in northeast Brazil. In this paper, we present data demonstrating the rate of weight gain in P. lineata neonates as a consistent measure of the stress imposed by sublethal concentrations of the herbicides Paraquat and Round-up. Our secondary agenda is to demonstrate the feasibility of incorporating bioassay into the standard municipal and state procedure of monitoring water quality. Growth data to assess chronic toxicity were generated in experiments of four and four, eight, twelve and sixteen days for Paraquat and Round-up, respectively. We estimated a 96 h no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) for Paraquat of 0.12 and 0.25 mg/L. The 96 h Round-up data yielded NOEC and LOEC values, respectively, of 0.25 and 0.5 mg/L. All concentrations of Round-up tested for the 192 h exposure yielded significantly lower growth than the control. Consequently, no NOEC could be derived. The LOEC was < 0.12 mg/L. Furthermore, there was no mortality during the test. At the lowest concentrations of Paraquat tested (0.005 mg/L) there was a significant increase in growth compared with the controls, suggesting a hormetic effect.     

Physiology and mRNA expression in rainbow trout (Oncorhynchus mykiss) after long-term exposure to the new antifoulant medetomidine

Medetomidine is under evaluation for use as an antifouling agent, and its effects on non-target aquatic organisms are therefore of interest. In this study, rainbow trout was exposed to low (0.5 and 5.0nM) concentrations of medetomidine for up to 54 days. Recently we have reported on effects on paleness and melanophore aggregation of medetomidine in these fish. Here, specific growth rates were investigated together with a broad set of physiological parameters including plasma levels of growth hormone (GH), insulin-like growth factor-I (IGF-I) and leptin, glucose and haemoglobin (Hb), hematocrit (Ht), condition factor, liver and heart somatic indexes (LSI, HSI). Hepatic enzyme activities of CYP1A (EROD activity), glutathione S-transferases (GST) and glutathione reductase (GR) were also measured. Additionally, hepatic mRNA expression was analysed through microarray and quantitative PCR in fish sampled after 31 days of exposure. Medetomidine at both concentrations significantly lowered blood glucose levels and the higher concentration significantly reduced the LSI. The mRNA expression analysis revealed few differentially expressed genes in the liver and the false discovery rate was high. Taken together, the results suggest that medetomidine at investigated concentrations could interfere with carbohydrate metabolism of exposed fish but without any clear consequences for growth.     

In vivo and in vitro activity of venom from the endoparasitic wasp Pimpla turionellae (L.) (Hymenoptera: Ichneumonidae)

The biological activity of venom from Pimpla turionellae L. (Hymenoptera: Ichneumonidae) was examined in vivo toward larvae and pupae of Galleriae mellonella L. (Lepidoptera: Pyralidae), and in vitro toward bacterial and fungal cultures, as well as cultured insect cells. Pupae of G. mellonella were far more susceptible to the venom than larvae. At low doses of venom [0.1 venom reservoir equivalents (VRE)], pupal abdominal mobility was inhibited within 30 min, and by 24 h, all pupae injected with venom concentrations >0.5 VRE were completely paralyzed. These same doses of venom resulted in an inhibition of adult emergence. Host larvae were far less sensitive to wasp venom as evidenced by all venom injected larvae remaining responsive to mechanical stimulation by 1 h post injection, even at concentrations equivalent to 1 venom reservoir. Eventually (>2 h at 25 degrees C), venom-injected larvae became immobile, then flaccid, and all died within 24 h post-injection. At lower concentrations of wasp venom, the onset of paralysis was delayed by comparison to that evoked by 1 VRE, and few host larvae were able to pupate. Development of host larvae to adult emergence was also reduced in a dose-dependent manner, with eclosion completely prevented at high concentrations (>0.5 VRE) of venom. Venom doses <0.5 VRE did not appear to induce paralysis or alter larval development. When venom was incubated with bacterial or fungal cultures, no antimicrobial activity was detected. However, wasp venom was found to be cytotoxic and cytolytic to cultured cells derived from the cabbage looper Trichoplusia ni Hubner (Lepidoptera: Noctuidae) and the yellow fever mosquito, Aedes aegypti (L.) (Diptera: Culcidae). Though both cell types displayed similar susceptibility in terms of LC50s, the lepidopteran cells responded much more rapidly with regard to the onset of morphological changes and the timing of cell death. A possible mode of action for the venom is discussed.     

Antigen uptake and immunoglobulin production in Atlantic cod (Gadus morhua L.) after intraperitoneal injection of Vibrio anguillarum

Atlantic cod (Gadus morhua L.) were injected intraperitoneally with formalin-killed Vibrio anguillarum bacteria. Immunostaining revealed uptake of V. anguillarum antigens especially in the spleen after intraperitoneal (i.p.) administration. The uptake was time dependent in the interval 1-24 h. Most of the antigen uptake in the spleen was concentrated in areas around small blood vessels, while immunoglobulin producing cells were localised to some thick walled arteries. There was apparently little or no co-localisation of antigens and antibody producing cells. In the heart, some of the high endocardial endothelial cells of the atrium contained bacterial antigens and in head kidney some macrophage-like cells were stained. Very little antigen was found in the pigmented loose connective tissues of the peritoneum. In contrast, endothelial cells of the underlying blood vessels contained substantial amounts. In the heart, peritoneum and anterior kidney the number of antigen positive cells did not seem to change in the time interval 1-24 h. After i.p. immunisation with a mixture of V. anguillarum and Freunds complete adjuvant, the humoral immune response in Atlantic cod was low when tested 21, 42 and 105 days later. There was apparently no enhanced number of immunoglobulin synthesising cells caused by the antigen stimulation.     

Measurements of larval Atlantic cod (Gadus morhua) routine metabolism: temperature effects, diel differences and individual-based modeling

In the present study, dry mass (M_D, μg) and routine respiration rate (R_R) (μl O₂ ind^?1 h^?1) were measured for larval cod, Gadus morhua (L.) that were reared and tested at 5.0, 7.5, and 10.0°C. Bi‐hourly measurements of R_R were made on groups of larvae using a closed‐circuit respirometer over a 24‐h period (14L : 10D light regime) to test temperature and body size effects and whether unfed larvae exhibited diel differences in metabolism. At 10°C, the relationship between mean R_R and mean M_D was: ln R_R = 1.16·lnM_D ? 6.57 (n = 31, r² = 0.883, P < 0.001). The exponential increase in R_R with temperature was described by a Q₁₀ of 3.00. Diel differences in unfed larvae were only apparent in groups of the largest larvae. A comparison of Q₁₀ estimates from this and other studies suggest a linear decrease in the effect of temperature on cod R_R with increasing log M_D for sizes encompassing larvae to large juveniles. The trend may explain, in part, observations of cod juveniles exploiting a wider range of in situ temperatures than larvae. Finally, the two most comprehensive data sets on larval cod R_R compare poorly (approximately five‐fold differences) and our results support the assertion that daily metabolic energy loss in many larval cod individual‐based models were based upon measurements that over‐estimated hourly metabolic rates by a factor of approximately four.     

Removal of chlorpyrifos by water lettuce (Pistia stratiotes L.) and duckweed (Lemna minor L.)

The potential of water lettuce (Pistia stratiotes L.) and duckweed (Lemna minor L.) to remove chlorpyrifos in water was investigated under laboratory greenhouse conditions. At initial chlorpyrifos concentrations of 0.0, 0.1 and 0.5 mg/L, the relative growth rates (RGR) of L. minor and P. stratiotes were not significantly different. In contrast, in the presence of 1 mg/L chlorpyrifos the RGR was significantly inhibited, giving an observed fresh weight based RGR(FW) for P. stratiotes and L. minor from day 0 to 7 of -0.036 and -0.023 mg/g/day, respectively. The maximum removal of chlorpyrifos by P. stratiotes and L. minor, when chlorpyrifos was at an initial culture concentration of 0.5 mg/L, was 82% and 87%, respectively, with disappearance rate constants under these conditions of 2.94, 10.21 and 12.14 microg h(-1) for the control (no plants), and with P. stratiotes and L. minor, respectively, giving actual corrected plant removal rate constants of 7.27 and 9.20 microg h(-1) for P. stratiotes and L. minor, respectively. The bioconcentration factor (BCF) of L. minor was significantly greater than that for P. stratiotes and therefore, at least under these greenhouse-based conditions, L. minor was more efficient than P. stratiotes for the accelerated removal of chlorpyrifos from water.     

Adrenoceptor compounds prevent the settlement of marine invertebrate larvae: Balanus amphitrite (Cirripedia), Bugula neritina (Bryozoa) and Hydroides elegans (Polychaeta)

The effects of the neurotransmitter blockers idazoxan and phentolamine on the larval settlement of three marine invertebrate species belonging to three different phyla were investigated by using in vitro concentration-response bioassays. Since neurotransmitters are known to influence metamorphic transitions in invertebrate larvae, neurotransmitter blockers were tested to evaluated their sublethal effects on larvae. The alpha-adrenergic antagonists idazoxan and phentolamine inhibited settlement of Balanus amphitrite (Cirripedia), Bugula neritina (Bryozoa) larvae, and larvae of the polychaete Hydroides elegans (Polychaeta) in a concentration-and taxon-dependent manner. At concentrations of 10(-3) M of both agents, larvae of all three species became immobile and subsequently died within 24 h. While cumulative settlement rates were observed after 48 h for B. amphitrite and H. elegans, and after 5 h for B. neritina, >90% of the larvae that settled did so within 24 h for the first two species and within 1 h for B. neritina. The tendency of the hydrophobic idazoxan and phentolamine to accumulate at solid surfaces most probably contributes to their successful inhibition of larval settlement. This ability makes them particularly attractive as candidates for the development of slow-release carriers in antifouling paints.     

Influence of Dimilin on a microsporidian infection in the gypsy moth Lymantria dispar (L.) (Lepidoptera: Lymantriidae)

Bioassay studies were conducted to investigate the influence of Dimilin (diflubenzuron), a chitinsynthetase inhibitor used for insecticidal control of the gypsy moth, Lymantria dispar, on the development and viability of a microsporidian pathogen of L. dispar. Before or after an infection with a Nosema species, L. dispar larvae were fed Dimilin in sublethal dosages. Dimilin fed to L. dispar larvae at 0.65 ng/cm² diet surface resulted in a total larval mortality of 53%. Although the microsporidian infection alone did not cause high mortality rates (9%), mortality increased to 96% when L. dispar larvae were inoculated with both Dimilin and Nosema spores. When Dimilin was fed to the larvae 24 h before or 6 days after inoculation with the microsporidium, the number of mature spores produced was significantly reduced. When Dimilin was fed to the larvae 24 h after microsporidian inoculation, the number of spores produced was not significantly reduced. Spores that were produced in larvae after Dimilin had been ingested with the diet were less infectious than spores produced in control larvae; the experimental infection rate decreased from 94% when spores obtained from control larvae were used, to 48 or 10% when spores obtained from larvae fed Dimilin 24 h or 6 days after Nosema inoculation, respectively, were used. Mature microsporidian spores washed in Dimilin solution prior to oral inoculation, however, were as infectious as spores stored in liquid nitrogen. We have shown that Dimilin interferes with the establishment of the parasite in its host. In addition, when Nosema sp. succeeds in infecting the L. dispar host despite treatment with Dimilin, the microsporidium does not develop optimally and spore production is reduced.     

Changes in Carbohydrate Levels in Red Kidney Bean (Phaseolus vulgaris L.) Exposed to Sulphur Dioxide

Red kidney bean (Phaseolus vulgaris L.) was exposed to variousconcentrations of SO² for 24 h (16 h light/8 h dark photoperiod)with continuous monitoring of photosynthetic and respiratoryactivity. Plants were harvested at the end of the dark periodinto samples of mature and immature leaf tissue, stems, androots for determination of sugar and starch levels. In all tissue samples the levels of total sugars were increasedby exposure to the lower concentrations of SO², but decreasedby the higher concentrations. Starch levels in leaves followeda similar trend. Increases in sugar and starch levels precededsymptoms of visible injury. Decreasing rates of photosynthesiswere correlated with increasing rates of respiration, the occurrenceof visible injury, and the depletion of sugar and starch levels.     

Cathepsin D from Atlantic cod (Gadus morhua L.) liver. Isolation and comparative studies

The isolated cathepsin D-like enzyme from Atlantic cod (Gadus morhua L.) liver was shown to be a monomer with a molecular mass of approximately 40 kDa. It was inhibited by Pepstatin A and had an optimum for degradation of haemoglobin at pH 3.0. The purified enzyme had lower temperature stability than bovine cathepsin D. Antibodies raised against the purified enzyme and against two C-terminal peptides of cod cathepsin D recognized a 40 kDa protein in immunoblotting of the samples from the purification process. Both antisera showed cross reactivity with a similar sized protein in liver from cod, saithe (Pollachius virens L.), Atlantic herring (Clupea harengus L.) and Atlantic salmon (Salmo salar L.). A protein of same size was detected in wolffish (Anarhichas lupus L.) liver with the antibody directed against the purified enzyme. This antibody also recognized the native enzyme and detected the presence of cathepsin D in muscle of cod, saithe, herring and salmon. These antibodies may be useful in understanding the mechanisms of post mortem muscle degradation in fish by comparing immunohistochemical localization and enzyme activity, in particular in cod with different rate of muscle degradation. They may also be used for comparing muscle degradation in different fish species.     

Sitona weevils (Coleoptera: Curculionidae) as agents for rapid transfer of nitrogen from white clover (Trifolium repens L.) to perennial ryegrass (Lolium perenne L.)

The effects of root feeding by larvae of Sitona hispidulus (F.) (a common weevil pest of white clover) on the rate of transfer of nitrogen between plants of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.) were investigated using a nutrient slant board technique. Clover plants, labelled with ¹⁵N were grown adjacent to ryegrass plants and were either infested with Sitona larvae or not infested. Ryegrass plants associated with the infested clover plants had a significantly higher dry matter yield and nitrogen content (75% and 74% respectively) than the uninvested plants, after 33 days exposure to insect herbivory. It was concluded that root feeding insects could play an important role in the cycling of nitrogen in grass/clover swards.     

Temperature induces trade-offs between development and starvation resistance in Aedes aegypti (L.) larvae

Heightened temperature increases the development rate of mosquitoes. However, in Aedes aegypti (Diptera: Culicidae), the larvae of which commonly experience limited access to food in urban habitats, temperature effects on adult production may also be influenced by changes in the capacity of larvae to survive without food. We carried out experiments to investigate the effects of temperatures increasing at intervals of 2 °C from 20 °C to 30 °C on the growth, maturation rate and longevity of optimally fed larvae placed in starvation. Overall, both growth rate and starvation resistance were lower in the first three larval instars (L1-L3) compared with L4, in which growth of >75% occurred. Although increasing the temperature reduced the duration of each instar, it had a U-shaped impact in terms of the effect of initial growth on starvation resistance, which increased from L1 to L2 at 20 °C and 30 °C, remained constant at 22 °C and 28 °C, and decreased at 24 °C and 26 °C. Growth from L2 to L3 significantly increased starvation resistance only from 26 °C to 30 °C. Increased temperature (>22 °C) consistently reduced starvation resistance in L1. In L2-L4, increments of 2 °C decreased starvation resistance between 20 °C and 24 °C, but had weaker and instar-specific effects at >24 °C. These data show that starvation resistance in Ae. aegypti depends on both instar and temperature, indicating a trade-off between increased development rate and reduced starvation survival of early-instar larvae, particularly in the lower and middle temperatures of the dengue-endemic range of 20-30 °C. We suggest that anabolic and catabolic processes in larvae have distinct temperature dependencies, which may ultimately cause temperature to modify the density regulation of Ae. aegypti populations.     

The ontogenic development of innate immune parameters of cod (Gadus morhua L.)

The aim of this study was to monitor the ontogenic development of innate immune parameters of cod (Gadus morhua L.) and to determine the presence of maternal IgM. The general protein composition and enzyme activity was also studied. At intervals, samples were collected of fertilized cod eggs and larvae from 3 days after fertilization until 57 days after hatching. Cell lysates were prepared and analysed by Western blotting using antibodies prepared against cod IgM, the complement component C3 and C-reactive protein (CRP) as well as against cod serum proteins and haemoglobin. Antibodies against salmon cathepsins and against several mammalian proteins of immunological significance were also used. Maternal IgM was not detected but C3 and the closely associated apolipoprotein A-I were present from the time of embryo organogenesis. C-reactive protein was not detected and none of the antibodies against mammalian immune parameters cross-reacted with the cod material. Protein and proteomic analysis showed that the major proteins of the egg samples were vitellogenin derived maternal proteins. Other non-vitellogenin maternal proteins, not yet identified, were also detected in the fertilized eggs. Cathepsin was present in all samples, but other enzyme activity was restricted to larval samples from 4 days after hatching when feeding had commenced. Haemoglobin was not detected until 10 days after hatching.