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The red lionfish Pterois volitans is important not only in the aquarium trade but also as an invasive species in the western Atlantic. Introduced to waters off the southeastern coast of the United States, red lionfish have rapidly spread along much of the East Coast and throughout Bermuda, the Bahamas, and much of the Caribbean. Hematology and plasma biochemistry were evaluated in red lionfish captured from the offshore waters of North Carolina to establish baseline parameters for individual and population health assessment. Blood smears were evaluated for total and differential white blood cell counts, and routine clinical biochemical profiles were performed on plasma samples. To improve the interpretive value of routine plasma biochemistry profiles, tissue enzyme activities (alkaline phosphatase [ALP], alanine aminotransferase [ALT], aspartate aminotransferase [AST], gamma-glutamyl transferase [GGT], lactate dehydrogenase [LD], and creatine kinase [CK]) were analyzed from liver, kidney, skeletal muscle, gastrointestinal tract, and heart tissues from five fish. The hematological and plasma biochemical values were similar to those of other marine teleosts except that the estimated white blood cell counts were much lower than those routinely found in many species. The tissue enzyme activity findings suggest that plasma LD, CK, and AST offer clinical relevance in the assessment of red lionfish.

Extracellular matrix in the ovarian follicle has been characterised for several mammalian species but there are no reports that describe the immunolocalisation of the extracellular matrix elements, matrix metalloproteinases, and its relation to plasma 17β estradiol levels and follicular apoptosis during the teleost's reproductive cycle. The present study used immunohistochemistry to characterise the distribution of laminin β2, collagen type IV, fibronectin and matrix metalloproteinases-9 (MMP-9). The TUNEL in situ technique was used to quantify apoptosis and indirect immunofluorimetric to determine plasma 17β estradiol levels. The TUNEL-positive reaction associated with morphological features exhibited follicular apoptosis. During postovulatory follicle involution, the drop in plasma 17β estradiol levels after spawning contributed to the intense apoptosis observed. By immunohistochemical analysis, laminin β2 and collagen type IV were identified as the major constituents of the basement membrane. The loss of integrity of the basement membrane occurred due to lyses of the major constituents, and coincides with increased follicular apoptosis. The integrity of the basement membrane is important for the survival of follicular cells. Furthermore, the MMP-9 results suggest that this enzyme is involved in final oocyte maturation and regression of postovulatory follicles. Fibronectin was observed on the surface of follicular cells of the postovulatory follicle in P. argenteus, this being important for maintaining normal cell adhesion to extracellular matrix. In conclusion, our results suggest that the structure and composition of the extracellular matrix, and plasma 17β estradiol levels related to apoptosis, play an important role during the follicular development and post-spawning involution in teleost fishes.

It has been previously demonstrated that vitellogenin (VTG)--a precursor egg yolk protein--is produced in male fish exposed to estrogenic compounds in wastewater treatment plant (WWTP) effluent. However, little attention has been given to examine whether any patterns of male VTG production exists across fish species on a global scale. We hypothesized that a composite measure of human population size over river discharge would best explain variations of protein levels in male fish. We compiled VTG data in 13 fish species from 43 rivers receiving municipal WWTP effluent on 3 continents. We found that human population size explained 28% of the variation in male VTG concentrations, whereas population/flow rate failed to significantly correlate with VTG. We suggest this result may be explained by the low solubility of estrogenic compounds, resulting in localized contamination near WWTP outfalls, rather than dilution by river water., (Copyright (c) 2010 Elsevier Ltd. All rights reserved.)

ALA-D activity and lead concentrations were measured in blood and liver tissues of the fish Prochilodus lineatus, collected from three locations along the coast of the La Plata River, Argentina. Two of them, Berazategui and Berisso, were located nearby the main ducts that discharge the urban and domestic waste disposal from Buenos Aires and La Plata cities, respectively, while the third station (Atalaya) was free of sewage discharges. For both tissues, the levels of lead in fish from Berazategui and Berisso were higher than those found in the samples from Atalaya. For blood, but not for liver, a significant negative correlation was found between ALA-activity and tissue levels of lead considering all the data. However, no good correlations were observed at each location. Therefore, an enzyme reactivation technique was optimized. The blood enzyme, but not the liver one, could be effectively reactivated with zinc (Zn(II)). The values of the reactivated ALA-D in samples from Berazategui and Berisso, but not from Atalaya, were significantly higher than the original values, indicating that the enzyme was actually inhibited. In addition, the reactivation index showed significant correlations with the blood lead levels. It is proposed that the reactivation index, rather than the ALA-D activity, may reflect better the extent of lead contamination, especially for field monitoring programs where many confounding factors may affect the biomarker response., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Roundup Transorb(RDT) is a glyphosate-based herbicide containing a mixture of surfactants. The objective of this work was to evaluate the effects of this herbicide on the Neotropical fish Prochilodus lineatus. Juvenile fish were acutely exposed (6, 24 and 96 h) to 1 mg L(-1) of RDT (RDT 1), 5 mg L(-1) of RDT (RDT 5) or only water (control) and blood samples for hematological analysis, liver for antioxidants analysis, and brain and muscle for acetylcholinesterase (AChE) determination, were collected. RDT effects were more evident in fish exposed to the higher concentration of the herbicide. Hematologic alterations appeared only after 96 h exposure, when fish showed an increase in the hematocrit and in the number of both red and white blood cells. After 6h exposure fish showed a transient reduction in superoxide dismutase and catalase activity. RDT also inhibited glutathione-S-transferase, after 6 and 24h of exposure. The reduction in these enzymes is probably related to the occurrence of lipid peroxidation (LPO) in fish exposed to the herbicide for 6h. LPO returned to control levels after 24 and 96 h exposure to RDT, when fish showed an increased activity of glutathione peroxidase. The content of reduced glutathione also increased after 96 h exposure. Thus, after 24 and 96 h the antioxidant defenses were apparently enough to combat ROS, preventing the occurrence of oxidative damage. The exposure to RDT for 96 h led to an inhibition of AChE in brain and muscle at rates which may not be considered a life-threatening situation., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

The region of Coatzacoalcos, Veracruz hosts one of the largest and most important industrial areas of Mexico and Latin America. Industrial development and rapid population growth, have triggered a severe impact on aquatic ecosystems of the region. The aim of this study was to determine the levels of POPs in sediment and in muscle tissue of five fish species from different trophic levels in downstream residents of the Coatzacoalcos River, and their integration with DNA damage in the fish, evaluated with the comet assay in whole blood as a biological indicator of stress, in order to obtain a baseline of the ecological condition of the region. The compounds detected in sediment and in muscle tissue were hexachlorobenzene (HCB), α-, β-, γ-hexachlorocyclohexane (HCH), dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), mirex and polychlorinated biphenyls (PCBs). Sediment concentrations of these pollutants (except for mirex) exceeded the values of protection provided by international guidelines, suggesting a potential risk to aquatic life in the region. DNA damage recorded in the fish species is evidence of exposure to a mix of genotoxic pollutants, which combined with exposure to POPs, reflects the degree of environmental stress of aquatic organisms in the region. The results of this study show the importance of determining the presence of contaminants in the environment, the bioaccumulation in tissues and their effects on exposed organisms, providing an integrated approach in assessing the health of aquatic ecosystems.

The effect of environmental salinity on hematological parameters of great sturgeon Huso huso juveniles was studied. Five-month-old juveniles (mean body weight 28.3 +/- 2.1 g) were subjected to 0, 3, 6, 9, and 12 ppt salinities. The hematological parameters were assessed after a period of 20 days rearing at these salinities. After transfer from fresh water to brackish water, red blood cells, hematocrit, haemoglobin and mean corpuscular haemoglobin decreased, but mean corpuscular volume increased. Mean corpuscular haemoglobin concentration, white blood cells, monocyte counts, and eosinophil counts showed no significant variations with increase in environmental salinity. An increase was found in lymphocyte counts according to the increase of salinity from 0 to 12 ppt, while the fresh water control group maintained basal levels. Decrease in neutrophil counts was observed in great sturgeon with increase in environmental salinity. These data show significant effect of salinity on the blood parameters of great sturgeon.

Status of serum electrolyte and nonelectrolyte variables can be used for managing sturgeon species cultured in freshwater or living in seawater. The aim of the present study was to evaluate serum biochemical variables in clinically healthy juvenile Persian sturgeon Acipenser persicus cultured in freshwater. Serum samples from 11 females and 10 males were analyzed, and levels (mean +/- SD) of the following variables were compared between sexes: glucose (Glc; 5.58 +/- 1.25 mmol/L for females and 8.56 +/- 1.80 mmol/L for males), total cholesterol (TC; 2.50 +/- 0.45 and 2.40 +/- 0.65 mmol/L), triglyceride (TG; 7.13 +/- 2.68 and 5.14 +/- 1.27 mmol/L), blood urea nitrogen (BUN; 1.28 +/- 0.2 and 1.01 +/- 0.2 mmol/L), total protein (TOP; 55.84 +/- 8.77 and 41.44 +/- 8.62 g/L), inorganic phosphate (P(i); 6.19 +/- 1.02 and 5.23 +/- 0.49 mmol/L), calcium (Ca; 2.80 +/- 0.43 and 2.63 +/- 0.32 mmol/L), magnesium (Mg; 0.9 +/- 0.23 and 0.99 +/- 0.22 mmol/L), sodium (Na; 152.80 +/- 13.81 and 156.38 +/- 12.67 mmol/L), potassium (K; 2.64 +/- 0.58 and 2.27 +/- 0.39 mmol/L), and chloride (Cl; 143 +/- 13.85 and 151.67 +/- 21.08 mmol/L). There were no differences in TC, Ca, Mg, Na, K, or Cl between sexes. The Glc value was lower in female Persian sturgeon than in males, whereas the values of TG, BUN, TOP, and P(i) were higher in females than in males. Freshwater adaptation may affect serum ion concentrations in juvenile Persian sturgeon.

The Acadian redfish (Sebastes fasciatus) is a popular display animal in public aquaria and an important fisheries resource, but hematologic values for this species have not been reported. This study investigated hematocrit, leucocyte counts, and leucocyte differential counts for 29 captive Acadian redfish collected in 2006 and 2008. All fish were judged to be in good health based on behavior, appetite, physical examination, skin cytology, and gill biopsy. Fish were anesthetized with tricaine methanesulfonate (MS-222) for blood collection from the ventral coccygeal vasculature. In 2008, MS-222 was buffered with sodium bicarbonate. Hematocrit values ranged from 27% to 45% (mean = 33% in 2006, mean = 31% in 2008). Leucocyte counts ranged from 670 to 35,000 cells/microl (mean = 6430 cells/microl in 2006, and 13,130 cells/microl in 2008). Lymphocytes were the most numerous of the leucocytes, followed by neutrophils and monocytes. Eosinophils and basophils were not seen. Fish weights were significantly greater in 2006, whereas total leucocyte counts, lymphocyte counts, and monocyte counts were significantly greater in 2008. Differences in leucogram values between the two groups may have been due to differences in size, age, anesthetic method, or other undetected factors. This is the first report of leucogram values for a species of the family Scorpaenidae. In general, values were similar to those of other teleosts, in which leucocyte counts can be quite variable.

Nitric oxide (NO)-mediated angiogenesis may play a role in establishing dense retinal vasculatures of Antarctic hemoglobinless icefishes (suborder: Notothenioidei). We hypothesized that loss of hemoglobin (Hb) leads to elevation in [NO] due to decreased degradation of the compound when the NO-scavenger Hb is absent, thereby inducing vascular growth. We found that total mass of NO metabolites, nitrite plus nitrate (NO(x)), in plasma is greater in icefishes than in red-blooded notothenioids [e.g. C. aceratus (Hb-), 22.7+/-2.9 microM; N. coriiceps (Hb+), 14.7+/-1.7 microM], suggesting a higher NO load in hemoglobinless animals. High NO levels do not appear to be a result of greater NO synthesis; we consistently measured lower activities of the enzyme catalyzing NO production, nitric oxide synthase, in tissues of icefishes than in Hb-expressing notothenioids [e.g. 96+/-10 and 216+/-39 pmol(min g wet wt)(-1) in brain tissue of C. aceratus (Hb-) and G. gibberifrons (Hb+), respectively]. Levels of mRNA for hypoxia-induced (HIF-1alpha and PHD2) and angiogenic genes (VEGF) were similar in red- and white-blooded species, indicating that vascular maintenance in adult animals does not require differences in angiogenic tone. This does not preclude a cause-and-effect relationship between absence of Hb and NO-mediated angiogenesis during earlier ontogenetic stages of icefishes., (Copyright (c) 2010 Elsevier Inc. All rights reserved.)

The Root effect, a reduction in blood oxygen (O(2)) carrying capacity at low pH, is used by many fish species to maximize O(2) delivery to the eye and swimbladder. It is believed to have evolved in the basal actinopterygian lineage of fishes, species that lack the intracellular pH (pH(i)) protection mechanism of more derived species' red blood cells (i.e., adrenergically activated Na(+)/H(+) exchangers; betaNHE). These basal actinopterygians may consequently experience a reduction in blood O(2) carrying capacity, and thus O(2) uptake at the gills, during hypoxia- and exercise-induced generalized blood acidoses. We analyzed the hemoglobins (Hbs) of seven species within this group [American paddlefish (Polyodon spathula), white sturgeon (Acipenser transmontanus), spotted gar (Lepisosteus oculatus), alligator gar (Atractosteus spatula), bowfin (Amia calva), mooneye (Hiodon tergisus), and pirarucu (Arapaima gigas)] for their Root effect characteristics so as to test the hypothesis of the Root effect onset pH value being lower than those pH values expected during a generalized acidosis in vivo. Analysis of the haemolysates revealed that, although each of the seven species displayed Root effects (ranging from 7.3 to 40.5% desaturation of Hb with O(2), i.e., Hb O(2) desaturation), the Root effect onset pH values of all species are considerably lower (ranging from pH 5.94 to 7.04) than the maximum blood acidoses that would be expected following hypoxia or exercise (pH(i) 7.15-7.3). Thus, although these primitive fishes possess Hbs with large Root effects and lack any significant red blood cell betaNHE activity, it is unlikely that the possession of a Root effect would impair O(2) uptake at the gills following a generalized acidosis of the blood. As well, it was shown that both maximal Root effect and Root effect onset pH values increased significantly in bowfin over those of the more basal species, toward values of similar magnitude to those of most of the more derived teleosts studied to date. This is paralleled by the initial appearance of the choroid rete in bowfin, as well as a significant decrease in Hb buffer value and an increase in Bohr/Haldane effects, together suggesting bowfin as the most basal species capable of utilizing its Root effect to maximize O(2) delivery to the eye.

Aerolysin is a significant virulent toxin protein secreted by Aeromonas hydrophila; it produces deep wound infections and hemorrhagic septicemia. The complete aerolysin gene (1,482 bp) was amplified from A. hydrophila. Furthermore, it was cloned and expressed into Escherichia coli BL21(DE3) codon plus RP cells using 0.5 mM IPTG for induction. The protein size was 54 kDa as estimated by SDS-PAGE, and it was purified by Ni-NTA affinity chromatography. Anti-His antibodies were used to characterize the expressed aerolysin by Western blotting and showed hemolytic activity with fish red blood cells. Aerolysin may be used as immunoassays for earlier control of A. hydrophila and is also compatible for vaccination.

The teleost fish Leporinus obtusidens (piava) was exposed to different concentrations of Roundup, a commercial herbicide formulation containing glyphosate (0, 1, or 5 mg L(-1)), for 90 days. Acetylcholinesterase (AChE) activity was verified in brain and muscle. Hepatic and muscular metabolic parameters as well as some hematological parameters were determined. The results showed that brain AChE activity was significantly decreased in fish exposed to 5 mg L(-1) Roundup, whereas muscular AChE activity was not altered. Both Roundup concentrations significantly decreased liver glycogen without altering the muscle glycogen content. Hepatic glucose levels were reduced only in fish exposed to 5 mg L(-1) Roundup. Lactate levels in the liver and muscle significantly increased in fish exposed to both Roundup concentrations. Hepatic protein content remained constant at 1 mg L(-1) but increased at 5 mg L(-1) Roundup. In the muscle however, protein content decreased with increasing exposure concentration. The herbicide exposure produced a decrease in hematological parameters at both concentrations tested. The majority of observed effects occur at environmental relevant concentrations, and in summary, the results show that Roundup affects brain AChE activity as well as metabolic and hematologic parameters of piavas. Thus, we can suggest that long-term exposure to Roundup causes metabolic disruption in Leporinus obtusidens.

The aquatic air-breathing fish, Trichogaster microlepis, can be found in fresh water and estuaries. We further evaluated the changes in two important osmoregulatory enzymes, Na(+)/K(+)-ATPase (NKA) and vacuolar-type H(+)-ATPase (VHA), in the gills when fish were subjected to deionized water (DW), fresh water (FW), and salinated brackish water (salinity of 10 g/L). Fish were sampled only 4 days after experimental transfer. The mortality, plasma osmolality, and Na(+) concentration were higher in 10 g/L acclimated fish, while their muscle water content decreased with elevated external salinity. The highest NKA protein abundance was found in the fish gills in 10 g/L, and NKA activity was highest in the DW and 10 g/L acclimated fish. The VHA protein levels were highest in 10 g/L, and VHA activity was highest in the DW treatment. From immunohistochemical results, we found three different cell populations: (1) NKA-immunoreactive (NKA-IR) cells, (2) both NKA-IR and HA-IR cells, and (3) HA-IR cells. NKA-IR cells in the lamellar and interlamellar regions significantly increased in DW and 10 g/L treatments. Only HA-IR cells in the lamellar region were significantly increased in DW. In the interlamellar region, there was no difference in the number of HA-IR cells among the three treated. From these results, T. microlepis exhibited osmoregulatory ability in DW and 10 g/L treatments. The cell types involved in ionic regulation were also examined with immunofluorescence staining; three ionocyte types were found which were similar to the zebrafish model., (Copyright 2009 Elsevier B.V. All rights reserved.)

Hematological studies on fishes have assumed greater significance due to the increasing emphasis on pisciculture and greater awareness of the pollution of natural water resources. Such studies have generally been used as an effective and sensitive index to monitor physiological and pathological changes in fishes, especially in the management of endangered species. This study was undertaken to establish a reference range for six important blood serum enzymes. Serum samples of 40 Acipenser stellatus (20 female and 20 male) were analyzed, and serum enzyme values were determined. The reference ranges for the total samples and also for each sex were determined. The activities of measured enzymes in serum were: aspartate aminotransferase (AST) 265.60 +/- 56.55 IU/l, alanine aminotransferase (ALT) 5.65 +/- 1.18 IU/l, acid phosphatase (ACP) 15.63 +/- 2.59 IU/l, lactate dehydrogenase (LDH) 2007.15 +/- 521.97 IU/l, creatine kinase (CK) 6,596.05 +/- 1,807.19 IU/l, and alkaline phosphatase (ALP) 69.05 +/- 13.04 IU/l. There were significant differences between male and female fish in terms of AST and CK activity (P < 0.05). These may be related to the season of sampling and changing physiological cycles during spawning during which period the sexual hormones and stress are more obvious. However, there were no differences in the activity of ALP, ACP, LDH, and ALT between sexes. The correlations between measured enzymes were also determined.

The effects of heat treatment and concentration of fish serum (FS) on cell growth in a suspension culture of recombinant Chinese hamster ovary (CHO) 1-15(500) (ATCC CRL-9606) cells were investigated. An increase in FS concentration from 1% to 4% markedly increased cell density. On the other hand, heat treatment of FS showed nearly no effect on cell density., (Copyright 2009 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

It is well documented that many coastal and estuarine environments adjacent to developed and industrialized urban centers, such as the San Francisco Bay Area, are significantly contaminated by anthropogenic chemicals. However, it is not well understood to what extent existing contaminants, many with continuing inflows into the environment, may impact exposed wildlife. This study provided an initial characterization of thyroid endocrine-related effects and their relationship to accumulated contaminants in two indigenous fish species sampled from different San Franicsco Bay Area study sites. Plasma concentrations of thyroxine (T4) were significantly reduced in fish sampled from highly impacted locations such as Oakland Inner Harbor and San Leandro Bay as compared with fish from other locations representing relatively lower human impact, including Bodega Bay, Redwood City and a remote site on Santa Catalina Island. Triiodothyronine (T3) levels also varied significantly by location, with differing T3/T4 ratios in fish from some locations suggestive of altered peripheral deiodinase activity. The changes in thyroid endocrine parameters were significantly correlated with hepatic concentrations of certain environmental contaminants. A large number of polychlorinated biphenyl (PCB) congeners, both co-planar (dioxin-like) and non-co-planar, exhibited significant inverse correlations with T4 levels in the fish, while in contrast, T3 and T3/T4 ratio were positively correlated with PCB exposures. The positive correlation between T3/T4 ratio and PCBs supports the hypothesis that environmental PCBs may alter T4 deiodination or turnover, actions of PCBs reported in laboratory experiments. Some relationships between chlorinated pesticides including DDT and chlordanes, but fewer relationships with PAHs, were also observed. Together, these findings indicate that the thyroid endocrine system is exhibiting alterations associated with different aquatic environments in the San Francisco Bay Area, which are significantly related to current-day exposures of the fish to contaminant chemicals such as PCBs., (2009 Elsevier B.V. All rights reserved.)

The interaction of methyl-parathion with serum and albumin of pacu, Piaractus mesopotamicus, was studied, using the fluorescence quenching technique. Pacu is a neo-tropical fish specie inhabitant of rivers from western regions of Brazil. Methyl-parathion (O,O-dimethyl O-p-nitrophenyl phosphorothioate) is an organophosphorous pesticide still used in agriculture and fish farming in many countries. The quenching of fluorescence can be mathematically expressed by the Stern-Volmer equation to calculate quenching constants. Stern-Volmer curves analysis is able to give important information about the pesticide-albumin interaction. Our results showed that the serum quenching reached 10% when the molar ratio of pesticide/albumin was about 7:1 for the three temperatures of the experiment. For the pure albumin quenching of 10%, methyl-parathion concentrations were 6, 7 and 9 times higher than albumin at 20, 25 and 30 degrees C, respectively. The calculated Stern-Volmer constants at 25 degrees C were 9.73x10(3)(+/-4.9x10(2))M(-1) for serum and 9.20x10(3)(+/-2.0x10(2))M(-1) for albumin. It was observed that albumin quenching is the phenomenon contributing to the quenching of the pacu serum fluorescence for methyl-parathion concentration lower than 10microM, suggesting that the protein is the most important carrier for the pesticide in serum.

O-Acetylation is one of the major modifications of sialic acids that significantly alters biological properties of the parent molecule. These O-acetylated forms are components of the cellular membrane and can affect physiological and pathological responses. Understanding the role of N-glycans in physiology is of increasing relevance to cellular biologists in various disciplines who study glycoproteomics yet lack information regarding the function of the attached glycans. However, permethylation, the most common mass spectrometric analytical means, leads to the loss of O-linked acetyl groups in sialic acids. In this chapter, we demonstrated that O-acetylation of sialic acid in Atlantic salmon serum N-glycan can be well investigated by capillary electrophoresis-mass spectrometry.

Adult mortality and low egg hatch rate were observed among American alligators Alligator mississippiensis in Lake Griffin, Florida, between 1998 and 2003. Previous studies show that the alligator mortality is due to neurological impairment associated with thiamine (vitamin Bt) deficiency. This study determined the rate of thiaminase activity in gizzard shad Dorosoma cepedianum, a fish often eaten by alligators, and examined the thiamine status of captive adult alligators fed only gizzard shad. We found that the thiaminase activity of gizzard shad in Lake Griffin is 16,409 +/- 2,121 pmol/g/min (mean +/- 2SEs). This high rate of thiaminase activity was present in most months and across a wide range of shad sizes. Seven alligators were captured in the wild from Lake Griffin and Lake Woodruff, held in captivity, and fed gizzard shad. We monitored blood and muscle thiamine levels throughout the experiment and liver thiamine at the end. Over a period of 6-12 months, all of the alligators maintained weight but blood and muscle thiamine levels decreased to 25-50% of the original (healthy) values. Three animals with the greatest reduction in thiamine died, demonstrating mobility impairment and neural histopathology similar to those seen in wild alligators in Lake Griffin. Two alligators were fed shad for 10 months but then treated with thiamine. These animals showed a reduction in thiamine while eating shad, but treatment restored their thiamine levels to the initial values, which were comparable to those of normal wild Lake Griffin alligators. We demonstrated that thiamine deficiency can be induced by a diet of gizzard shad and cause neurological signs and death in alligators in captivity. We conclude that the thiaminase activity in gizzard shad is high enough to cause thiamine deficiency in wild alligators when shad are a major part of their diet.

The objective of this study was determination and discrimination of biochemical data among three aquaculture-affected marine fish species (sea bass, Dicentrarchus labrax; sea bream, Sparus aurata L., and mullet, Mugil spp.) based on machine-learning methods. The approach relying on machine-learning methods gives more usable classification solutions and provides better insight into the collected data. So far, these new methods have been applied to the problem of discrimination of blood chemistry data with respect to season and feed of a single species. This is the first time these classification algorithms have been used as a framework for rapid differentiation among three fish species. Among the machine-learning methods used, decision trees provided the clearest model, which correctly classified 210 samples or 85.71%, and incorrectly classified 35 samples or 14.29% and clearly identified three investigated species from their biochemical traits.

Specimens of the west African lungfish, Protopterus annectens (mean weight 294.3 g mean length 38.1 cm), procured from Agulu lake at Agulu in Anambra state, Nigeria were removed from the ambient water and exposed to complete aerial life for a period of seven consecutive days after which some of their haematological changes were determined. There were significant polycythaemia, leucocytosis, thrombocythaemia and elevation of haemoglobin contents (p<0.05). The importance of these haematological adjustments which the fish makes whilst subjected to complete aerial habitat prior to aestivation are discussed.

The efficiency of different reductants (reduced glutathione, ascorbic acid, and catalase) and metal chelators [ethylenediaminetetraacetic acid (EDTA), citric acid, sodium tripolyphosphate (STPP), and adenosine-5'-triphosphate (ATP)] to inhibit lipid oxidation promoted by fish hemoglobin was investigated. The inhibitory activity on hemoglobin-catalyzed lipid oxidation was also evaluated for grape oligomeric catechins (proanthocyanidins), which have both reducing and chelating properties. The antioxidant activity was studied in two different lipid oxidation models, liposomes and washed minced fish muscle. Grape proanthocyanidins were found to be significantly more effective than other reductants to prevent hemoglobin-mediated lipid oxidation in both liposomes and washed fish muscle. Reduced glutathione was also efficient to retard lipid oxidation at the same molarity in washed fish muscle, whereas catalase and ascorbic acid showed a lower antioxidant activity. Metal chelators were less active than reductants, and consequently, the former were necessarily evaluated at much higher concentration than grape proanthocyanidins and reducing compounds. STPP was found to be the iron chelator with the strongest efficiency to delay hemoglobin-mediated lipid oxidation followed by EDTA. Citric acid and ATP were ineffective in retarding lipid oxidation in both systems. Grape proanthocyanidins provided the most extensive protection to preserve hemoglobin at ferrous state in washed fish muscle. Our results draw attention to the greater capacity of reducing compounds to prevent fish hemoglobin-mediated lipid oxidation in comparison with iron chelators, suggesting that the free radical scavenging and/or reduction of ferrylHb species are crucial actions to avoid the pro-oxidant capacity of fish hemoglobin.

To our knowledge, this is the first report of concentrations of perfluorooctanesulfonate (PFOS) and other perfluoroalkyl acids (PFAs) in marine organisms from the industrialized region of Korea. Concentrations of eight PFAs were determined in three species of fish (mullet, shad, and rockfish) and three species of marine invertebrates (blue crab, oyster, and mussel) from Lake Shihwa, Korea. This is an area in which relatively great concentrations of PFAs in water and in adjacent industrial effluents have been reported. PFOS was the dominant PFA in marine organisms and most PFOS concentrations were greater than the sum of all other PFAs. The mean concentrations of PFOS were 8.1 x 10 and 3.6 x 10 ng/g, wet weight in liver and blood of fish, respectively. Perfluorocarboxylic acids (PFCAs) were also found in fish, but their concentrations were 10-fold less than those for PFOS. Of the PFCAs measured in fish, concentrations of the longer-chain perfluoroundecanoic acid (PFUnA) were the greatest. Concentrations of PFOS in soft tissues of blue crabs decreased as a function of distance from the shore where inputs from the industrialized areas are discharged into Lake Shihwa. PFOS was the only PFA detectable in mussels and oysters with a mean of 0.5 +/- 0.2 and 1.1 +/- 0.3 ng/g, wet weight, respectively. Concentrations of PFUnA were positively correlated with perfluorodecanoic acid (PFDA) in both the liver and blood of fish, which suggests a common source of these two PFCAs in this area. Hazard quotients developed for fish species were all less than 1.0 for fish collected in Lake Shihwa.

Hemoglobin (Hb) from rainbow trout (Oncorhynchus mykiss), Atlantic cod (Gadus morhua), and herring (Clupea harengus) were evaluated in terms of capacity to generate hydroperoxide-derived free radicals in aqueous solution at pH 6.8. Cumene hydroperoxide (CumOOH) was used as a model for preformed lipid hydroperoxides, and free radicals were monitored by stabilizing with the spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) and further detection by electron spin resonance spectroscopy. The generation of hydroperoxide-derived free radicals was found to be Hb concentration-dependent, and intermediate Hb concentrations corresponding to hydroperoxide/Hb molar ratios of roughly 200 were found most active. The results indicated the following relative activity in the formation of hydroperoxide-derived free radicals under low and medium hydroperoxide levels (hydroperoxide/Hb molar ratios < or =5): cod Hb approximately herring Hb > trout Hb. This free radical generating-activity was not affected by heating fish hemoglobins at 70 degrees C for 10 and 45 min in aqueous solution. Cod and herring Hb also exhibited faster autoxidation rates and stronger redox instability in the presence of hydroperoxides compared to trout Hb. According to their ability to generate hydroperoxide-derived free radicals, hemoglobin from cod and herring showed more activity than trout Hb as catalysts of lipid oxidation in lecithin liposomes. These data emphasize the central contribution of the free radicals formed through hydroperoxide-decomposition on the hemoglobin-mediated lipid oxidation.

The effects of acute stressors on physiological responses of juvenile great sturgeon or beluga Huso huso L. were investigated in two experiments. In the first experiment, fish were handled by placing them in containers at either low density (LD, one fish l(-1)) or high density (HD, four fish l(-1)) for 60 s. Concentrations of plasma cortisol, glucose and lactate were determined from blood collected at 0, 1, 3, 6 and 12 h after application of the stressor. Plasma cortisol concentrations increased after the disturbance in H. huso from both handling treatments, but changes were not significant. Plasma glucose rose significantly by 22.9 and 31.6% in LD and HD handling treatments, respectively, after 3 h. Significant increases in plasma lactate occurred within 1 h in both treatment groups, but that of the HD group was much higher. In the second experiment, fish were held at two different densities, LD (2 kg m(-2) tank bottom surface area) and HD (7 kg m(-2)), for 8 weeks and then subjected to an aerial emersion handling stressor in a net for 60 s; blood samples were taken before handling (resting, 0 h) and at 1, 3, 6 and 9 h after handling. Plasma cortisol increased significantly in fish from the HD treatment from 8.8 +/- 0.3 to 19.2 +/- 2.4 ng ml(-1) (mean +/-s.e.) by 1 h after stress, but post-handling changes in the LD group were not significant. Significant increases in both plasma glucose and lactate were observed by 1 h in both treatment groups, with peak levels of plasma glucose evident at 3 h [69.4 +/- 2.9 and 60.9 +/- 1.7 mg dl(-1) (mean +/-s.e.) in LD and HD groups, respectively]. Plasma glucose levels were significantly higher in the LD group than in the HD group at 3 and 6 h. Post-handling haemoglobin content increased by 1 h and white blood cell numbers were reduced by 3 and 6 h in the HD treatment group compared with resting values, but changes in these blood features in the LD group were not significant. Acute handling did not affect haematocrit in either treatment. The results suggest that H. huso is relatively resistant to handling and confinement, and could tolerate normal hatchery practices associated with aquaculture. Because changes in cortisol concentrations were relatively low compared with those in most teleosts, glucose and lactate concentrations may be more useful as stress indicators in juvenile H. huso. This study also demonstrated that prior exposure to a chronic stressor, specifically high stocking density, could alter the physiological response to subsequent acute handling in H. huso.

In the event of an influenza pandemic, anti-viral medications such as oseltamivir (Tamiflu) are expected to be used in high amounts over a duration of several weeks. Oseltamivir has been predicted to reach high concentrations in surface waters and sewage works. New oseltamivir environmental fate and toxicity studies permit an environmental risk assessment (ERA) under seasonal- and pandemic-use scenarios. The environmental fate data for sewage works (no removal), surface waters (no significant degradation), and water/sediment systems (>50% primary degradation in 100 days) were used for the derivation of new predicted environmental concentrations (PECs) for western Europe and the River Lee catchment in the UK. Existing worst-case PECs for western Europe, the River Lee catchment in the UK and the Lower Colorado basin in the USA under pandemic conditions (< or =98.1 microg/L for surface waters, < or =348 microg/L for sewage works) were also considered for the ERA. PECs were compared with predicted no-effect concentrations (PNECs) based on new chronic ecotoxicity data (no observed effect concentration for algae, daphnia, and fish > or =1 mg/L). Based on all PEC/PNEC risk ratios, no significant risk is evident to surface waters or sewage works during both regular seasonal-use and high pandemic-use of oseltamivir.

The hemolytic activity of the dinoflagellate Cochlodinium polykrikoides from Bahía de La Paz, Gulf of California was investigated as part of the ichthyotoxic mechanism of this microalga. Two different kinds of erythrocytes, fish and human, were tested for the hemolytic assay. Since fatty acids have been associated with hemolytic activity in C. polykrikoides, the composition of fatty acids of this dinoflagellate was also analyzed. The concentration of C. polykrikoides causing 50% hemolysis (HE(50)) was 4.88 and 5.27x10(6) cellsL(-1), for fish and human erythrocytes, respectively. According to the standard curve of saponin, an equivalence between the hemolytic activity of saponin and the dinoflagellate concentration was found with 1mug saponinmL(-1) equivalent to 1x10(6) cellsL(-1) of C. polykrikoides. The polyunsaturated fatty acids: hexadecaenoic (16:0), docosahexaenoic (22:6 n3) and octadecapentaenoic (18:5 n3) were found in an abundance of approximately 62% of total fatty acids.

Antarctic fish live in very cold water and have adapted to this exceptional environment. Hemoglobin is absent or very low; yet these fish still have erythrocytes, and from these we prepared ghost-like membranes. We studied for the first time the lipid composition of ghost membranes and of plasma in Antarctic fish (C. hamatus and T. bernacchii) and compared our results with those obtained for temperate-water fish (C. auratus and A. anguilla taken from Lake Trasimeno, Perugia, Italy). The membranes of Antarctic fish were richer in glycerophospholipid (especially phosphatidylethanolamine), whereas the membranes of temperate-water fish were richer in sphingomyelin. Unsaturated fatty acids were particularly abundant in Antarctic fish: C. hamatus had long-chain unsaturated fatty acid (especially C22:6 omega-3), whereas T. bernacchii had shorter unsaturated fatty acyl chains (c16:1, omega-7). On the other hand, C. auratus and A. anguilla were particularly rich in C16:0, which constituted more than one-half of the total fatty acid. Plasma lipids (both phospholipid and cholesterol) were much more abundant in temperate-water fish. The differences in phospholipid content were mainly due to choline glycerolipids. Measures of membrane fluidity inferred from the fluorescence anisotropy of DPH indicated that the membranes from Antarctic fish were more fluid at any measured temperature than those obtained from fish living in temperate waters. The ability to live in a very cold environment has therefore been achieved by the two Antarctic species tested in this paper by different strategies, but with the same results on fluidity.

The effects of capture (chasing, netting and air exposure) on cortisol, glucose, chloride, sodium, potassium and calcium concentrations, osmolality, hematocrit, hemoglobin concentration, red blood cells count (RBC) and mean corpuscular volume (MCV) were investigated in pacu (Piaractus mesopotamicus). A total of 132 fish (49.7 +/- 11.7 g) were subjected to capture and 3 minutes air exposure and capture and 5 minutes air exposure. Nine fish at each treatment were sampled at 5, 15, 30, 60 minutes and 24 hours after the procedure. Nine undisturbed fish were sacrificed before the handling and used as controls. Capture resulted in a rise in blood cortisol and glucose 30 and 5 minutes, respectively, after both air exposures. Both indicators returned to resting levels 24 hours after capture. In both fish groups, plasma chloride decreased 60 minutes after capture, not recovering the resting levels within 24 hours after, and serum sodium rose at 15 and 30 minutes and recovered the resting levels 24 hours later. There were no significant changes neither in potassium, calcium and osmolality nor in hematocrit, hemoglobin, RBC and MCV as a consequence of capture. The sequential stressors imposed to pacu during capture activated the brain-pituitary-interrenal axis (cortisol and glucose responses) but the activation of the brain-sympathetic-chromaffin cell axis was apparently moderate (ionic and hematological responses).

We have undertaken comparative studies of the number and phenotypes of erythrocytes in the peripheral blood of red crucian carp (RCC), blunt snout bream (BSB), and their hybrids, including triploids, tetraploids, and pentaploids. The results indicate that the mean nuclear volume of erythrocytes in peripheral blood increases regularly with increasing ploidy. Furthermore, many more mature erythrocytes have a dumbbell nucleus in the peripheral blood of polyploid hybrids compared with their diploid parents. With the increase in ploidy level, the percentage of such erythrocytes increases. The polyploid hybrids also have a large number of erythrocytes with abnormal shapes. For example, round and tear-shaped erythrocytes have been observed in the peripheral blood of polyploid hybrids. Since the erythrocytes in polyploid hybrids with their larger volume and lower specific surface area are unfavorable for the conveyance of oxygen, morphological variations of erythrocytes might improve defective blood circulation.

A biosensor system was developed for continuous estimation of blood glucose in fish. Because it is difficult to measure blood components in real-time due to decreased sensor output resulting from blood coagulation and coalescing blood proteins at the sensor placement site, we used the eyeball scleral interstitial fluid (EISF) as the site of sensor implantation. Evaluation of the relationship between EISF and blood glucose concentrations revealed that the blood glucose concentration correlated closely with the EISF glucose concentration (y=2.2996+0.9438x, R=0.960, n=112). To take advantage of the close correlation between blood and EISF glucose, we prepared a needle-type enzyme sensor for implantation in the fish sclera using a flexible wire electrode. The sensor provided a rapid response, good linearity, and reproducibility. Continuous glucose monitoring could be carried out by implanting this needle-type glucose sensor onto the eye. The findings indicated that the glucose concentration increased with sensor output current over time, and that changes in the blood glucose were continuously reflected in the EISF. The glucose concentration was estimated based on the one-point or two-point calibration methods. The two-point calibration method yielded the most accurate glucose monitoring (blood glucose range of 70-420 mg dL(-1)) over 160 min. Sensor-estimated glucose and whole blood glucose values were highly correlated (y=0.4401+0.8656x, R=0.958).

We examined for the first time the hemoglobin components of the blood of the Australian lungfish, Neoceratodus forsteri and their functional responses to pH and the allosteric modulators adenosine triphosphate (ATP), guanosine triphosphate (GTP), 2,3-bisphosphoglyceric acid (BPG) and inositol hexaphosphate (IHP) at 25 degrees C. Lysates prepared from stripped, unfractionated hemolysate produced sigmoidal oxygen equilibrium curves with high oxygen affinity (oxygen partial pressure required for 50% hemoglobin saturation, p(50)=5.3 mmHg) and a Hill coefficient of 1.9 at pH 7.5. p(50) was 8.3 and 4.5 mmHg at pH 6 and 8, respectively, which corresponded to a modest Bohr coefficient (Delta log p(50)/Delta pH) of -0.13. GTP increased the pH sensitivity of oxygen binding more than ATP, such that the Bohr coefficient was -0.77 in the presence of 2 mmol L(-1) GTP. GTP was the most potent regulator of hemoglobin affinity, with concentrations of 5 mmol L(-1) causing an increase in p(50) from 5 to 19 mm Hg at pH 7.5, while the order of potency of the other phosphates was IHP>ATP>BPG. Three hemoglobin isoforms were present and each contained both alpha and beta chains with distinct molecular weights. Oxygen affinity and pH-dependence of isoforms I and II were essentially identical, while isoform III had a lower affinity and increased pH-dependence. The functional properties of the hemoglobin system of Neoceratodus appeared consistent with an active aquatic breather adapted for periodic hypoxic episodes.

DNA-protein cross-links (DPXs) in fish erythrocytes represent a potential biomarker for exposure to metal cations, such as hexavalent chromium (Cr[VI]) and divalent nickel (Ni[II]). Species-specific sensitivities to DPX formation were studied by coexposure of juvenile specimens of rainbow trout, hybrid bluegill, and channel catfish to waterborne metals, such as Cr(VI) and Ni(II). In a species comparison, 4 days of exposure to 2 ppm Cr(VI) induced highest DPXs in bluegill erythrocytes, followed by trout and catfish, at 186%, 97%, and 48% above controls, respectively. A similar pattern of species sensitivity was observed following co-exposure of the fish to 15 ppm Ni(II) for 4 days, with 237%, 124%, and 82% increased DPXs above control bluegill, trout, and catfish, respectively. Biological stability of Cr(VI)-induced DPXs was demonstrated in Cr(VI)-exposed bluegill, as DPX levels remained elevated for up to 20 days after discontinuation of exposure. Similar results were found following exposure of catfish to Ni(II), with detectable DPXs found 10 days after acute exposure. In both bluegill and catfish, a continued increase in DPX formation in erythrocytes was seen for 5-10 days after Cr(VI) was removed from tank water, suggesting that residual Cr(VI) may be involved in DPX formation following acute exposure of fish.

Chemical risk assessment procedures assign a major role to standardized toxicity tests, in which the response of a particular organism to a single test substance is determined under otherwise constant and favorable conditions in the laboratory. This approach fails to consider the potential for chemical interactions, as well as failing to consider how the toxicological response varies, depending on the conditions of exposure. As yet, the issue of confounding factors on chemically mediated effects in wildlife has received little attention, despite the fact that a range of physicochemical parameters, including temperature, water quality, and pH, are known to modify chemical toxicity. Here, we consider how the estrogenic response of fish varies with regard to hypoxia. Fathead minnows (Pimephales promelas) were exposed to a mixture of estrogenic chemicals under hypoxic or normoxic conditions. Their estrogenic response was characterized using an in vivo assay, involving the analysis of the egg yolk protein, vitellogenin (VTG). The results revealed that there was no effect of hypoxia on the VTG response in either treatment group at the end of the exposure period. This suggests that this end point is robust and relatively insensitive to the effects of any physiological changes that arise as a result of hypoxia. The implications of these negative findings are discussed in terms of their relevance with regard to the development of risk assessment policy.

The availability of whole-genome sequences for a variety of vertebrates is making it possible to reconstruct the step-by-step evolution of complex phenomena such as blood coagulation, an event that in mammals involves the interplay of more than two dozen genetically encoded factors. Gene inventories for different organisms are revealing when during vertebrate evolution certain factors first made their appearance in or, on occasion, disappeared from some lineages. The whole-genome sequence databases of two protochordates and seven nonmammalian vertebrates were examined in search of approximately 20 genes known to be associated with blood clotting in mammals. No genuine orthologs were found in the protochordate genomes (sea squirt and amphioxus). As for vertebrates, although the jawless fish have genes for generating the thrombin-catalyzed conversion of fibrinogen to fibrin, they lack several clotting factors, including two thought to be essential for the activation of thrombin in mammals. Fish in general lack genes for the "contact factor" proteases, the predecessor forms of which make their first appearance in tetrapods. The full complement of factors known to be operating in humans does not occur until pouched marsupials (opossum), at least one key factor still absent in egg-laying mammals such as platypus.

The African (Protopterus sp.) and South American lungfish (Lepidosiren paradoxa) inhabit shallow waters, that seasonally dry out, which induces aestivation and cocoon formation in Protopterus. Differently, L. paradoxa has no cocoon, and it aestivates in a simple burrow. In water PaCO(2) is 21.8+/-0.4mmHg (mean values+/-S.E.M.; n=5), whereas aestivation for 20 days increased PaCO(2) to as much as 37.6+/-2.1mmHg, which remained the same after 40 days (35.8+/-3.3mmHg). Concomitantly, the plasma [HCO(3)(-)]-values for animals in water were 22.5+/-0.5mM, which after 20 days increased to 40.2+/-2.3mM and after 40 days to 35.8+/-3.3mM. Initially in water, PaO(2) was 87.7+/-2.0mmHg, but 20 days in aestivation reduced the value to 80.5+/-2.2 and later (40 days) to 77.1+/-3.0mmHg. Meanwhile, aestivation had no effect on pHa and hematocrit. The blood pressures were equal for animals in the water or in the burrow (P(mean) approximately 30mmHg), and cardiac frequency (f(H)) fell from 31beats min(-1) to 22beats min(-1) during 40 days of aestivation. The osmolality (mOsmkgH(2)O(-1)) was elevated after 20 and 40 days of aestivation but declined upon return to water. The transition from activity to aestivation involves new set-points for the variables that determine the acid-base status and PaO(2) of the animals, along with a reduction of cardiac frequency.

Perfluorinated compounds (PFCs) were measured in zooplankton and five fish species collected from Gaobeidian Lake, which receives discharge from wastewater treatment plant (WWTP) in Beijing, China. The mean total PFCs in five fish were in the order: crucian carp>common carp>leather catfish>white semiknife carp>tilapia. Perfluorooctane sulfonate (PFOS) occurred at the greatest concentrations, with mean concentrations ranging from 5.74 to 64.2 ng/ml serum. Perfluorodecanoic acid (PFDA) was the second dominant PFC in fish samples except for common carp in which perfluorooctane sulfonamide (PFOSA) was dominant. A positive linear relationship (r(2)=0.85, p<0.05) was observed between lnPFOS concentrations (ln ng/ml) and trophic level (based on delta15N) if tilapia was excluded. The risk assessment showed that PFOS might not pose an immediate risk to fish in Gaobeidian Lake.

A lipoprotein-like antifreeze protein (type IV AFP) has previously been isolated only from the blood plasma of the longhorn sculpin. However, the plasma antifreeze activity in all individuals of this species tested from Newfoundland and New Brunswick waters ranges from low to undetectable. A close relative of the longhorn sculpin, the shorthorn sculpin, does have appreciable antifreeze activity in its blood but this is virtually all accounted for by the alpha-helical, alanine-rich type I AFP, other isoforms of which are also present in the skin of both fishes. We have characterized a putative ortholog of type IV AFP in shorthorn sculpin by cDNA cloning. This 12.2-kDa Gln-rich protein is 87% identical to the longhorn sculpin's type IV AFP. Recombinant versions of both orthologs were produced in bacteria and shown to have antifreeze activity. Immunoblotting with antibodies raised to type IV AFP shows this protein present in longhorn sculpin plasma at levels of less than 100 microg/mL, which are far too low to protect the blood from freezing at the temperature of icy seawater. This confirms the results of direct antifreeze assays on the plasmas. It appears that type IV AFP has the potential to develop as a functional antifreeze in these fishes but may not have been selected for this role because of the presence of type I AFP. Consistent with this hypothesis is the observation that the type IV AFP gene has not been amplified the way functional antifreeze protein genes have in all other species examined.

A simplified method for quantitative analysis of fatty acids in various matrices by gas chromatography is proposed as an alternative to the conventional method and the variables of the protocol examined to optimize the processing conditions. The modified method involves direct methylation of fatty acids in homogenized samples with boron trihalide (BF(3) or BCl(3) in methanol) followed by extraction with hexane. The addition of hexane to the reaction mixture after the methylation process can enhance the efficiency of fatty acid methylation and is critical for those samples that contain high levels of triglycerides. A mechanism underlying this effect is proposed.

The aim of this research was to study how high water temperatures impair the reproductive activity of pejerrey Odontesthes bonariensis, an inland-water atherinopsid fish species from the pampasic region of Argentina. Adult pejerrey of both sexes were kept under a control-temperature regime (19 degrees C) and two experimental temperatures (23 degrees and 27 degrees C) for 8 d. The effect of elevated temperature on the pituitary-gonad axis was analyzed in terms of the expression of gonadotropin (GtH) subunits: follicle-stimulating hormone beta, luteinizing hormone beta (LH-beta), glycoprotein hormone alpha, and GtH receptors FSH-R and LH-R by semiquantitative reverse transcriptase polymerase chain reaction, plasma levels of sexual steroids by radioimmunoassay, and reproductive status by gonadal histology. The results of this work clearly indicate that short periods of exposure to high water temperatures disrupt pejerrey reproduction. This effect was observed in spawning activity, at the histological level, and in the reduction of plasma estradiol in females and testosterone in males. The mRNA levels of GtH subunits and GtH receptors generally decreased in proportion to the increase in temperature for both sexes. However, the differences between groups were statistically significant only for LH-beta and for FSH-R expression in pejerrey females. Thus, the gonads of pejerrey appear to be the primary target of high water temperature. Analysis of the air temperature in this region over the past 40 yr indicated an increase of 1.74 degrees C in mean annual temperature. This increase, coupled with the mechanism of high-temperature sensitivity shown in this study, may be one of the reasons for the decline in pejerrey populations observed in this region over recent decades.

The environment impacts on the physiology and psychology of animals in a wide variety of ways. If we can develop an understanding of how different environmental factors affect different processes we may be able to predict these changes and avoid or moderate deleterious events and the resultant changes in fish health and disease resistance. In this review, advances in the understanding of environmental impacts were identified in relation to specific areas of immune function. The trends, where they can be identified, showed that increases in light, temperature, salinity, oxygen, pH or particulates results in a general increase in immune function.

The stable metabolite of nitric oxide in plasma is NOx, the sum of nitrite plus nitrate. Measures of plasma NOx may provide information about the nitric oxide tonus of the entire endothelium including capillary microvessels. Although data are available for mammalian species, plasma NOx measurements in early vertebrate species are scarce. The purpose of this study was to test the hypothesis that plasma NOx would be similar to the NO in the water environment for fish in early classes (Agnatha and Chondrichthye) and would exceed water NOx levels in the known nitrite-sensitive fish (Osteichthye). Plasma samples were obtained from 18 species of adult fish (n=167) and from their housing or natural water environment. NOx was measured by using chemiluminescence. Plasma NO was detected in all species and ranged from 0.5 nmol/ml (skate) to 453.9 nmol/ml (shortnose gar). Average plasma NOx was significantly higher in sea lamprey than in Atlantic hagfish whereas that of little skate was 3-fold lower than in spiny dogfish shark. Plasma NO differed significantly among early bony fish (paddlefish, pallid sturgeon, gar) yet was similar among modern bony fish, with the exception of rainbow trout. Plasma NOx reflected water NO in only 2 species (hagfish and shark), and levels did not coincide with nitrite sensitivity. This study provides an expanded comparative view of plasma NO, levels across 3 groups of early fish. The data obtained suggest a nitric oxide system in early and modern fish.

We investigated the effect of environmental salinity on the upper thermal tolerance of green sturgeon (Acipenser medirostris), a threatened species whose natural habitat is vulnerable to temperature and salinity variation as a result of global climate change. Freshwater (FW)-reared sturgeon were gradually acclimated to salinities representing FW, estuary water (EST), or San Francisco Bay water (BAY) at 18 degrees C, and their critical thermal maximum (CTMax) was measured by increasing temperature 0.3 degrees C/min until branchial ventilation ceased. CTMax was 34.2+/-0.09 degrees C in EST-acclimated fish, with FW- and BAY-acclimated fish CTMax at 33.7+/-0.08 and 33.7+/-0.1 degrees C, respectively. Despite the higher CTMax in EST-acclimated fish, FW-acclimated sturgeon ventilation rate reached a peak that was 2 degrees C higher than EST- and BAY-acclimated groups and had a greater range of temperatures within which they exhibited normal ventilatory function as assessed by Q10 calculation. The osmoregulatory consequences of exposure to near-lethal temperatures were assessed by measuring plasma osmolality and hematocrit, as well as white muscle, brain, and heart tissue water contents. Hematocrit was increased following CTMax exposure, most likely owing to the elevated metabolic demands of temperature increase, and plasma osmolality was significantly increased in EST- and BAY-acclimated fish, which was likely the result of a greater osmotic gradient across the gill as metabolism increased. To our knowledge, this represents the first evidence for an effect of salinity on the upper thermal tolerance of sturgeon, as well as the first investigation of the osmoregulatory consequences of exposure to near-lethal temperatures., (Copyright 2008 Wiley-Liss, Inc.)

Organochlorine (OC) pesticide concentrations in blood plasma samples from 88 juvenile white sturgeon collected from the lower Columbia River were measured and compared to plasma sex steroid and OC tissue levels previously measured in corresponding fish. Significant squared correlation coefficients between summation operator DDT concentrations in sturgeon plasma and gonads and livers were 0.37 and 0.32, respectively. Significant negative correlations between plasma testosterone concentration and plasma Sigma DDT concentration in male fish (r(2)=0.26), plasma 17beta estradiol concentration and plasma Sigma DDT concentration in female fish (r(2)=0.38) and condition factor and plasma Sigma DDT concentration in all fish were found (r(2)=0.17). These results suggest that blood plasma may be a suitable nondestructive method for monitoring adult sturgeon population for persistent OC contaminants.

Parameters of the antioxidant defense systems of Brycon amazonicus (matrinxã--a neotropical fish) exposed to phenol for 96 h plus the recovery over 1 and 2 weeks were studied in erythrocytes and liver. Hematocrit increase was observed during phenol exposure and recovery for 1 week. Total superoxide dismutases (SOD), glutathione peroxidase (GPx) and reduced glutathione (GSH) did not change during phenol exposure. Erythrocyte glucose-6-phosphate dehydrogenase (G6PDH) increased during that period while catalase (CAT) activity decreased during phenol exposure and recovery for 2 weeks. In the liver, SOD and CAT did not change, whereas GPx increased in the first week of recovery and decreased after 2 weeks. A late response was observed for G6PDH activity which increased only at the second week. Ascorbate concentration in the brain decreased during phenol exposure and increased over recovery. From our results it appears that the oxidative stress was limited in matrinxã exposed to phenol, but seemed to occur during the recovery period.

The aim of this study was to describe the effect of hypoxia on whole body ion fluxes and hematological parameters in two Amazonian teleosts: Serrasalmus eigenmanni and Metynnis hypsauchen. The increase of Na+ and Cl- effluxes on M. hypsauchen exposed to hypoxia may be related to an increase of gill ventilation and effective respiratory surface area, to avoid a reduction in the oxygen uptake, and/or with the decrease of pHe, that could inhibit Na+ and Cl- transporters and, therefore, reduce influx of these ions. Effluxes of Na+ and Cl- were lower in hypoxia than in normoxia for S. eigenmanni, possibly because in hypoxia this species would reduce gill ventilation and oxygen uptake, which would lead to a decrease of gill ion efflux and, consequently, reducing ion loss. The increase on hematocrit (Ht) during hypoxia in M. hypsauchen probably was caused by an increase of the red blood cell volume (MCV). For S. eigenmanni the increase on glucose possibly results from the usage of glucose reserve mobilization. Metynnis hypsauchen showed to be more sensitive to hypoxia than Serrasalmus eigenmanni, since the first presented more significant alterations on these osmoregulatory and hematological parameters. Nevertheless, the alterations observed for both species are strategies adopted by fishes to preserve oxygen supply to metabolizing tissues during exposure to hypoxia.

Blood proteins of true sturgeons of three genera Acipenser, Huso, and Pseudocaphirhynchus preserving unidirectional variability in ontogenesis regardless of peculiarities of the fish ecology can indicate unity of origin of the current species. Age-related protein transformations have heterochronous character. The slowest ontogenetic development lasting 4-6 years is peculiar to one of antigens of beta-globulins. Analysis of variability of beta-globulins in the age diapason beginning from the 4-month-old fry and including adult spawned individuals indicates different functional significance of their individual components. The beta A-globulin absent at early postembryonic stages becomes the second, after albumin, quantitatively predominant antigen in the adult fish blood. The amount of beta B-globulin, like antigens of alpha 1- and alpha 2-globulins preserving relative ontogenetic stability, can decrease significantly in freshwater sturgeons due to their preparation for spawning.

In this study we measured plasma cortisol, plasma glucose, plasma sodium and potassium, and liver and gill hsp70 levels in juvenile matrinxã (Brycon amazonicus) subjected to a 96 h exposure to phenol (0, 0.2, and 2.0 ppm), and the effect of this exposure on their ability to respond to a subsequent handling stress. Fish were sampled prior to initiation of exposure and 96 h, and at 1, 6, 12, and 24 h post-handling stress. During the 96 h exposure, plasma cortisol and glucose levels remained unchanged in all treatments. While plasma sodium levels were significantly reduced in all groups, plasma potassium levels only decreased in fish exposed to 0 and 0.2 ppm of phenol. Liver hsp70 levels decreased significantly at 96 h in fish exposed to 2.0 ppm of phenol. All groups, except fish exposed to 0.2 ppm of phenol, were able to increase plasma cortisol and glucose levels after handling stress. Fish exposed to 2.0 ppm of phenol showed decreased gill and liver hsp70 levels after the handling stress. Our data suggest that exposure to phenol may compromise the ability of matrinxã to elicit physiological responses to a subsequent stressor.