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At least 127 records · Page 7Linked to original sources
USGS1981

Plasma corticosterone and thyroxine concentrations during chronic ingestion of crude oil in mallard ducks ( Anas platyrhynchos )

1. Blood samples were collected from mallard ducks after 6, 12, and 18 weeks of dietary exposure to mash containing 0.015%, 0.150%, and 1.500% crude oil. 2. Plasma corticosterone concentrations in ducks fed mash containing 0.150% or 1.500% Alaskan Prudhoe Bay crude oil were uniformly depressed when compared to values in untreated control birds. 3. Plasma thyroxine concentration was not altered in ducks chronically exposed to crude oil. 4. The observed alteration in corticosterone concentration could reduce tolerance to temperature and dietary fluctuations in the environment.

Comparative Biochemistry and Physiology, Part C: C↗
USGS1982

Organophosphate inhibition of avian salt gland Na, K-ATPase activity

1. Adult black ducks ( Anas rubripes ) were given freshwater or saltwater (1.5% NaCl) for 11 days and half of each group was also given an organophosphate (17 p.p.m. fenthion) in the diet on days 6–11. 2. After 11 days, ducks drinking saltrwater had lost more weight and had higher plasma Na and uric acid concentration and osmolalities than birds drinking freshwater. 3. Saltwater treatment stimulated the salt gland to increased weight and Na, K-ATPase activity. 4. Fenthion generally reduced plasma and brain cholinesterase activity and depressed cholinesterase and Na, K-ATPase activities in salt glands of birds drinking saltwater.

Comparative Biochemistry and Physiology, Part C: C↗
USGS1984

Avian species differences in the intestinal absorption of xenobiotics (PCB, dieldrin, Hg 2+ )

1. Intestinal absorption of a polychlorinated biphenyl, dieldrin, and mercury (from HgCl 2 ) was measured in adult Northern bobwhites, Eastern screech owls, American kestrels, black-crowned night-herons and mallards in vivo by an in situ luminal perfusion technique. 2. Bobwhites, screech owls and kestrels absorbed much more of each xenobiotic than black-crowned night-herons and mallards. 3. Mallards absorbed less dieldrin and mercury than black-crowned night-herons. 4. Mercury absorption by kestrels was more than twice that in screech owls and eight times that observed in mallards. 5. Pronounced differences in xenobiotic absorption rates between bobwhites, screech owls and kestrels on the one hand, and black-crowned night-herons and mallards on the other, raise the possibility that absorptive ability may be associated with the phylogenetic classification of birds.

Comparative Biochemistry and Physiology, Part C: C↗
USGS1985

Biochemical and hematological effects of lead ingestion in nestling American kestrels ( Falco sparverius )

1. One-day old American kestrel ( Faico sparverius ) nestlings were orally dosed daily with 5 μl/g of corn oil (controls), 25, 125 or 625 mg/kg of metallic lead in corn oil for 10 days. 2. Forty per cent of the nestlings receiving 625 mg/kg of lead died after 6 days and growth rates were significantly depressed in the two highest lead dosed groups. At 10 days hematocrit values were significantly lower in the two highest lead treated groups, and hemoglobin content and red blood cell (δ-aminolevulinic acid dehydratase (ALAD) activity was depressed in all lead treated groups. Plasma creatine phosphokinase decreased in the two highest treatment groups. 3. Brain, liver and kidney ALAD activities, brain RNA to protein ratio and liver protein concentration decreased after lead exposure whereas liver DNA, DNA to RNA ratio and DNA to protein ratio increased. Brain monoamine oxidase and ATPase were not significantly altered. 4. Measurements of the ontogeny of hematological variants and enzymes in normal development, using additional untreated nestlings, revealed decreases in red blood cell ALAD, plasma aspartate amino transferase, lactate dehydrogenase, brain DNA and RNA and liver DNA, whereas hematocrit, hemoglobin, plasma alkaline phosphatase, brain monoamine oxidase, brain ALAD and liver ALAD increased during the first 10 days of posthatching development. 5. Biochemical and hematological alterations were more severe than those reported in adult kestrels or precocial young birds exposed to lead. Alterations may be due in part to delayed development.

Comparative Biochemistry and Physiology, Part C: C↗
USGS1986

Depression of plasma luteinizing hormone concentration in quail by the anticholinesterase insecticide parathion

1. To examine the effects of parathion on basal plasma luteinizing hormone (LH) concentration, male Japanese quail ( Coturnix japonica ) were orally intubated with 0, 5 or 10 mg/kg parathion and sacrificed after 4, 8 and 24 hr. 2. At the 5 mg/kg dose, plasma LH levels were reduced at 4 and 8 hr, but returned to control values by 24 hr. Brain acetylcholinesterase activity was substantially reduced by 10 mg/kg parathion (52, 75 and 37% inhibition at 4, 8 and 24 hr, respectively) and plasma LH concentration remained depressed through the 24-hr period. 3. These findings suggest that the organophosphorus insecticide parathion may alter plasma LH concentration in a manner which might impair reproductive activity, and provide indirect evidence for a cholinergic component in the regulation of LH secretion in quail.

Comparative Biochemistry and Physiology, Part C: C↗
USGS1993

Comparative cardiovascular effects of four fishery anesthetics in spinally transected rainbow trout, oncorhynchus mykiss

1. We compared the effects of four anesthetics on heart rate, dorsal and ventral aortic blood pressure, and electrocardiograms of rainbow trout ( Oncorhynchus mykiss ). 2. Exposure to the local anesthetics tricaine methanesulfonate (MS-222) and benzocaine hydrochloride (BZH) produced minimal cardiovascular alterations. Mean dorsal aortic pressure (DAP) decreased during exposure to MS-222, and mean DAP and mean ventral aortic pressure (VAP) increased 15% during recovery from BZH. 3. Exposure to the general anesthetic 2-phenoxyethanol (2-PE) or the hypnotic agent etomidate (ET) dramatically decreased heart rate and blood pressures and altered EKG patterns. 4. During recovery, VAP and DAP increased above baseline for an extended period. Heart rate and EKG patterns rapidly returned to normal.

Comparative Biochemistry and Physiology, Part C: C↗
USGS1994

A review of lead poisoning in swans

Nearly 10,000 swans of six species or subspecies from 14 countries have died from poisoning caused by lead that originated from ingestion of fishing weights, shotgun pellets (shot), or contaminated vegetation or sediments associated with mining and smelting wastes. Lead contamination in mute swans in England caused local population declines during the late 1970s and 1980s. More tundra swans died from lead poisoning than any other species. The extreme record involved an estimated 7200 tundra swans that died over five winters at one locality in North Carolina. The recent legislation to ban lead fishing weights in most of England and Wales and recent replacement of lead shot with steel shot for waterfowl hunting in the United States and a few areas of Europe, including Denmark, are expected to reduce the incidence of lead poisoning in swans.

Comparative Biochemistry and Physiology, Part C: P↗
USGS1996

Regional cholinesterase activity in white-throated sparrow brain is differentially affected by acephate (Orthene®)

Effects of a 14-day dietary exposure to an organophosphorus pesticide, acephate (acetylphosphoramidothioic acid O,S-dimethyl ester), were determined on cholinesterase activity in three regions (basal ganglia, hippocampus, and hypothalamus) of the white-throated sparrow, Zonotrichia albicollis , brain. All three regions experienced depressed cholinesterase activity between 0.5–2 ppm acephate. The regions exhibited cholinesterase recovery at 2–16 ppm acephate; however, cholinesterase activity dropped and showed no recovery at higher dietary levels (>16 ppm acephate). Evidence indicates that the recovery is initiated by the magnitude of depression, not the duration. In general, as acephate concentration increased, differences in ChE activity among brain regions decreased. Three terms are introduced to describe ChE response to acephate exposure: 1) ChE resistance threshold, 2) ChE compensation threshold, and 3) ChE depression threshold. It is hypothesized that adverse effects to birds in the field may occur at pesticide exposure levels customarily considered negligible.

Comparative Biochemistry and Physiology, Part C: P↗
USGS2006

Conservation of Toll-like receptor signaling pathways in teleost fish

In mammals, toll-like receptors (TLR) recognize ligands, including pathogen-associated molecular patterns (PAMPs), and respond with ligand-specific induction of genes. In this study, we establish evolutionary conservation in teleost fish of key components of the TLR-signaling pathway that act as switches for differential gene induction, including MYD88, TIRAP, TRIF, TRAF6, IRF3, and IRF7. We further explore this conservation with a molecular phylogenetic analysis of MYD88. To the extent that current genomic analysis can establish, each vertebrate has one ortholog to each of these genes. For molecular tree construction and phylogeny inference, we demonstrate a methodology for including genes with only partial primary sequences without disrupting the topology provided by the high-confidence full-length sequences. Conservation of the TLR-signaling molecules suggests that the basic program of gene regulation by the TLR-signaling pathway is conserved across vertebrates. To test this hypothesis, leukocytes from a model fish, rainbow trout ( Oncorhynchus mykiss ), were stimulated with known mammalian TLR agonists including: diacylated and triacylated forms of lipoprotein, flagellin, two forms of LPS, synthetic double-stranded RNA, and two imidazoquinoline compounds (loxoribine and R848). Trout leukocytes responded in vitro to a number of these agonists with distinct patterns of cytokine expression that correspond to mammalian responses. Our results support the key prediction from our phylogenetic analyses that strong selective pressure of pathogenic microbes has preserved both TLR recognition and signaling functions during vertebrate evolution.

Comparative Biochemistry and Physiology, Part D: G↗
USGS2007

Peptidomic analysis of skin secretions supports separate species status for the tailed frogs, Ascaphus truei and Ascaphus montanus

The tailed frog Ascaphus truei Stejneger, 1899 is the most primitive extant anuran and the sister taxon to the clade of all other living frogs. The species occupies two disjunct ranges in the Northwest region of North America: the Cascade Mountains and coastal area from British Columbia to Northern California, and an inland range in the northern Rocky Mountains and the Blue and Wallowa mountains. A previous study led to the isolation of eight peptides with antimicrobial activity (termed the ascaphins) from skin secretions of A. truei from the coastal range. The present study has used peptidomic analysis to identify the products of orthologous ascaphin genes in electrically-stimulated skin secretions from inland range specimens. Structural characterization of the peptides demonstrated that ascaphins from the inland range contained the following amino acid substitutions compared with orthologs from the coastal range frogs: ascaphin-1 (Ala 12 → Glu), ascaphin-3 (Asp 4 → Glu), ascaphin-4 (Ala 19 → Ser), ascaphin-5 (Lys 12 → Thr), and ascaphin-7 (Gly 8 → Ser and Ser 20 → Asn). Orthologs of ascaphins-2, -6, and -8 were not identified but a paralog of ascaphin-5, identical to ascaphin-5 from coastal range frogs, was found. The data support the claims, derived from analysis of the nucleotide sequences of mitochondrial genes, that the inland populations of the tailed frog should be recognized as a distinct species, the Rocky Mountain tailed frog Ascaphus montanus and that the divergence of the species from A. truei probably occurred in the late Miocene (approximately 10 Mya).

Comparative Biochemistry and Physiology, Part D: G↗
USGS2007

Gene expression in the liver of rainbow trout, Oncorhynchus mykiss , during the stress response

To better appreciate the mechanisms underlying the physiology of the stress response, an oligonucleotide microarray and real-time RT-PCR (QRT-PCR) were used to study gene expression in the livers of rainbow trout ( Oncorhynchus mykiss ). For increased confidence in the discovery of candidate genes responding to stress, we conducted two separate experiments using fish from different year classes. In both experiments, fish exposed to a 3 h stressor were compared to control (unstressed) fish. In the second experiment some additional fish were exposed to only 0.5 h of stress and others were sampled 21 h after experiencing a 3 h stressor. This 21 h post-stress treatment was a means to study gene expression during recovery from stress. The genes we report as differentially expressed are those that responded similarly in both experiments, suggesting that they are robust indicators of stress. Those genes are a major histocompatibility complex class 1 molecule ( MHC1 ), JunB , glucose 6-phosphatase ( G6Pase ), and nuclear protein 1 ( Nupr1 ). Interestingly, Nupr1 gene expression was still elevated 21 h after stress, which indicates that recovery was incomplete at that time.

Comparative Biochemistry and Physiology, Part D: G↗
USGS2012

Transcriptional profiling of the parr–smolt transformation in Atlantic salmon

The parr–smolt transformation in Atlantic salmon ( Salmo salar ) is a complex developmental process that culminates in the ability to migrate to and live in seawater. We used GRASP 16K cDNA microarrays to identify genes that are differentially expressed in the liver, gill, hypothalamus, pituitary, and olfactory rosettes of smolts compared to parr. Smolts had higher levels of gill Na + /K + -ATPase activity, plasma cortisol and plasma thyroid hormones relative to parr. Across all five tissues, stringent microarray analyses identified 48 features that were differentially expressed in smolts compared to parr. Using a less stringent method we found 477 features that were differentially expressed at least 1.2-fold in smolts, including 172 features in the gill. Smolts had higher mRNA levels of genes involved in transcription, protein biosynthesis and folding, electron transport, oxygen transport, and sensory perception and lower mRNA levels for genes involved in proteolysis. Quantitative RT-PCR was used to confirm differential expression in select genes identified by microarray analyses and to quantify expression of other genes known to be involved in smolting. This study expands our understanding of the molecular processes that underlie smolting in Atlantic salmon and identifies genes for further investigation.

Comparative Biochemistry and Physiology, Part D: G↗
USGS2016

Transcriptome discovery in non-model wild fish species for the development of quantitative transcript abundance assays

Environmental studies increasingly identify the presence of both contaminants of emerging concern (CECs) and legacy contaminants in aquatic environments; however, the biological effects of these compounds on resident fishes remain largely unknown. High throughput methodologies were employed to establish partial transcriptomes for three wild-caught, non-model fish species; smallmouth bass ( Micropterus dolomieu ), white sucker ( Catostomus commersonii ) and brown bullhead ( Ameiurus nebulosus ). Sequences from these transcriptome databases were utilized in the development of a custom nCounter CodeSet that allowed for direct multiplexed measurement of 50 transcript abundance endpoints in liver tissue. Sequence information was also utilized in the development of quantitative real-time PCR (qPCR) primers. Cross-species hybridization allowed the smallmouth bass nCounter CodeSet to be used for quantitative transcript abundance analysis of an additional non-model species, largemouth bass ( Micropterus salmoides ). We validated the nCounter analysis data system with qPCR for a subset of genes and confirmed concordant results. Changes in transcript abundance biomarkers between sexes and seasons were evaluated to provide baseline data on transcript modulation for each species of interest.

Comparative Biochemistry and Physiology, Part D: G↗
USGS2008

Effects of ACTH, capture, and short term confinement on glucocorticoid concentrations in harlequin ducks ( Histrionicus histrionicus )

Little is known about baseline concentrations of adrenal hormones and hormonal responses to stress in sea ducks, although significant population declines documented in several species suggest that sea ducks are exposed to increased levels of environmental stress. Such declines have been observed in geographically distinct harlequin duck populations. We performed an adrenocorticotropic hormone (ACTH) challenge to evaluate adrenal function and characterize corticosterone concentrations in captive harlequin ducks and investigated the effects of capture, surgery, and short term confinement on corticosterone concentrations in wild harlequin ducks. Harlequin ducks responded to the ACTH challenge with an average three-fold increase in serum corticosterone concentration approximately 90 min post injection, and a four- to five-fold increase in fecal glucocorticoid concentration 2 to 4 h post injection. Serum corticosterone concentrations in wild harlequin ducks increased within min of capture and elevated levels were found for several hours post capture, indicating that surgery and confinement maintain elevated corticosterone concentrations in this species. Mean corticosterone concentrations in wild harlequin ducks held in temporary captivity were similar to the maximum response levels during the ACTH challenge in captive birds. However, large variation among individuals was observed in responses of wild birds, and we found additional evidence suggesting that corticosterone responses varied between hatch year and after hatch year birds.

Comparative Biochemistry and Physiology, Part A: M↗
USGS2010

Annual sex steroid and other physiological profiles of Pacific lampreys ( Entosphenus tridentatus )

We documented changes in plasma levels of estradiol 17-β (E2), progesterone (P), 15α-hydroxytestosterone (15α-T), thyroxine (T4), triiodothyronine (T3), protein, triglycerides (TGs), and glucose in adult Pacific lampreys ( Entosphenus tridentatus ) held in the laboratory in two different years. Levels of E2 in both sexes ranged from 0.5 to 2 ng/mL from September to March, peaked in late April (2–4 ng/mL), and decreased in May, with levels higher in males than in females. Levels of P were low from September through April, but then increased substantially during May (2–4 ng/mL), with levels again highest in males. Levels of 15α-T in males were around 0.75 ng/mL through the winter before exceeding 1 ng/mL in April and decreasing thereafter, whereas females showed a gradual increase from 0.25 ng/mL in November to 0.5 ng/mL in April before decreasing. Thyroxine concentrations differed between fish in each year, with most having levels ranging from 0.75 to 2.5 ng/mL in the fall and winter, and only fish in 2003 showing distinct peaks (3–4 ng/mL) in early April or May. Plasma T3 was undetectable from November through mid-March before surging dramatically in April (ca. 150 ng/mL) and decreasing thereafter. Levels of protein, TGs, and glucose decreased or were stable during the fall and winter with TGs and glucose surging in late April to early May for some fish. Our study is the first to document long-term physiological changes in Pacific lampreys during overwintering and sexual maturation and increases our understanding of the life history of this unique fish.

Comparative Biochemistry and Physiology, Part A: M↗
USGS2016

Salinity effects on plasma ion levels, cortisol, and osmolality in Chinook salmon following lethal sampling

Studies on hydromineral balance in fishes frequently employ measurements of electrolytes following euthanasia. We tested the effects of fresh- or salt-water euthanasia baths of tricaine mesylate (MS-222) on plasma magnesium (Mg 2+ ) and sodium (Na + ) ions, cortisoland osmolality in fish exposed to saltwater challenges, and the ion and steroid hormone fluctuations over time following euthanasia in juvenile spring Chinook salmon ( Oncorhynchus tshawytscha ). Salinity of the euthanasia bath affected plasma Mg 2+ and Na + concentrations as well as osmolality, with higher concentrations in fish euthanized in saltwater. Time spent in the bath positively affected plasma Mg 2+ and osmolality, negatively affected cortisol, and had no effect on Na + concentrations. The difference of temporal trends in plasma Mg 2+ and Na + suggests that Mg 2+ may be more sensitive to physiological changes and responds more rapidly than Na + . When electrolytes and cortisol are measured as endpoints after euthanasia, care needs to be taken relative to time after death and the salinity of the euthanasia bath.

Comparative Biochemistry and Physiology, Part A: M↗
USGS2018

Shifts in the relationship between mRNA and protein abundance of gill ion-transporters during smolt development and seawater acclimation in Atlantic salmon (Salmo salar)

Smolting Atlantic salmon exhibit a seasonal increase in seawater tolerance that is associated with changes in the abundance of major gill ion-transporter transcripts and proteins. In the present study, we investigate how the transcript and protein abundance of specific ion-transporter isoforms relate to each other during smolt development and seawater acclimation, and how each correlates to seawater tolerance. We show that during smolt development both mRNA and protein abundance of gill Na + /K + -ATPase α1a subunit (NKAα1a) decreased but the decrease in the mRNA was five-times greater than that of the protein. Gill NKAα1b mRNA levels increased only slightly (1.5-fold) throughout development whereas protein abundance increased 30-fold at its peak. Gill Na + /K + /2Cl − co-transporter 1 (NKCC1) increased at the mRNA and protein level (5- and 12-fold) in smolts. The abundance of a gill ion-transporter's mRNA and protein changed in the same direction through development and after seawater transfer, but the changes were not always strongly correlated: NKAα1a ( r = 0.768), NKAα1b ( r = 0.40), and NKCC1 ( r = 0.898). The maintenance of plasma chloride concentration correlated most strongly with the abundance of NKAα1a mRNA, and the ratio of NKAα1b to NKAα1a mRNA and protein. Growth performance after seawater transfer correlated most strongly with the abundance of NKAα1b protein and the ratio of NKAα1b to NKAα1a protein. Our results indicate that the abundance of ion-transporter mRNA and protein do not always correlate well and a decrease in the abundance of gill NKAα1a mRNA and increase in NKAα1b protein are strong predictors of seawater tolerance and growth performance after seawater transfer.

Comparative Biochemistry and Physiology, Part A: M↗
USGS2024

Dopaminergic and anti-estrogenic responses in juvenile steelhead (Oncorhynchus mykiss) exposed to bifenthrin

The frequency of detection and concentrations of bifenthrin, a pyrethroid insecticide, in the waterways inhabited by the endangered species, steelhead trout ( Oncorhynchus mykiss ), has become a significant concern for regulatory agencies. Endocrine disruption has been observed with estrogenic and anti-estrogenic responses in fish species at different life stages. Since several studies have indicated alterations in dopaminergic signaling associated with endocrine responses, juvenile steelhead were exposed to environmentally relevant concentrations of 60 or 120 ng/L bifenthrin for two weeks. Fish brains were assessed for dopamine levels and the expression of genes involved in dopaminergic and estrogenic processes, such as catechol- o -methyltransferase ( comt ) and monoamine oxidase ( mao ). Vitellogenin ( vtg ) and estrogenic receptors ( ERα1 , ERβ1 , and ERβ2 ) were also evaluated in livers of the animals. Dopamine concentrations were significantly higher in fish brains following bifenthrin exposure. Consistent with a reduction in dopamine clearance, there was a significant decrease in the mRNA expression of comt with increased bifenthrin concentration. Hepatic expression of ERα1 and ERβ2 mRNA was significantly decreased with increased bifenthrin concentration. These data support the possible mechanism of bifenthrin altering the dopaminergic pathway at low ng/L concentrations, in juvenile steelhead, which could interfere with endocrine feedback loops. These findings support the need for and importance of identifying species and life stage differences in pesticide modes of action to reduce uncertainties in risk assessments.

Comparative Biochemistry and Physiology Part C: To↗