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At least 55 records · Page 3Linked to original sources
USGS2024

Evaluation of anticoagulant rodenticide sensitivity by examining in vivo and in vitro responses in avian species, focusing on raptors

Anticoagulant rodenticides (ARs) are used to control pest rodent species but can result in secondary poisoning of non-target animals, especially raptors. In the present study, differences in AR sensitivity among avian species were evaluated by comparing in vivo warfarin pharmacokinetics and effects, measuring cytochrome P450s (CYPs) expression involved in AR metabolism, and conducting in vitro inhibition assays of the AR target enzyme Vitamin K 2,3-epoxide reductase (VKOR). Oral administration of warfarin at 4 mg/kg body weight did not prolong prothrombin time in chickens ( Gallus gallus ), rock pigeons ( Columba livia ), or Eastern buzzards ( Buteo japonicus ). Rock pigeons and buzzards exhibited shorter plasma half-life of warfarin compared to chickens. For the metabolite analysis, 4′-hydroxywarfarin was predominantly detected in all birds, while 10-hydroxywarfarin was only found in pigeons and raptors, indicating interspecific differences in AR metabolism among birds likely due to differential expression of CYP enzymes involved in the metabolism of ARs and variation of VKOR activities among these avian species. The present findings, and results of our earlier investigations, demonstrate pronounced differences in AR sensitivity and pharmacokinetics among bird species, and in particular raptors. While ecological risk assessment and mitigation efforts for ARs have been extensive, AR exposure and adverse effects in predatory and scavenging wildlife continues. Toxicokinetic and toxicodynamic data will assist in such risk assessments and mitigation efforts.

Environmental Pollution↗
USGS2014

In vitro immune functions in thiamine-replete and -depleted lake trout ( Salvelinus namaycush )

In this study we examined the impacts of in vivo thiamine deficiency on lake trout leukocyte function measured in vitro. When compared outside the context of individual-specific thiamine concentrations no significant differences were observed in leukocyte bactericidal activity or in concanavalin A (Con A), and phytohemagglutinin-P (PHA-P) stimulated leukocyte proliferation. Placing immune functions into context with the ratio of in vivo liver thiamine monophosphate (TMP – biologically inactive form) to thiamine pyrophosphate (TPP – biologically active form) proved to be the best indicator of thiamine depletion impacts as determined using regression modeling. These observed relationships indicated differential effects on the immune measures with bactericidal activity exhibiting an inverse relationship with TMP to TPP ratios, Con A stimulated mitogenesis exhibiting a positive relationship with TMP to TPP ratios and PHA-P stimulated mitogenesis exhibiting no significant relationships. In addition, these relationships showed considerable complexity which included the consistent observation of a thiamine-replete subgroup with characteristics similar to those seen in the leukocytes from thiamine-depleted fish. When considered together, our observations indicate that lake trout leukocytes experience cell-type specific impacts as well as an altered physiologic environment when confronted with a thiamine-limited state.

Fish & Shellfish Immunology↗
USGS2010

The combined influence of sub-optimal temperature and salinity on the in vitro viability of Perkinsus marinus, a protistan parasite of the eastern oyster Crassostrea virginica

Perkinsus marinus is a major cause of mortality in eastern oysters along the Gulf of Mexico and Atlantic coasts. It is also well documented that temperature and salinity are the primary environmental factors affecting P. marinus viability and proliferation. However, little is known about the effects of combined sub-optimal temperatures and salinities on P. marinus viability. This in vitro study examined those effects by acclimating P. marinus at three salinities (7, 15, 25. ppt) to 10 ??C to represent the lowest temperatures generally reached in the Gulf of Mexico, and to 2 ??C to represent the lowest temperatures reached along the mid-Atlantic coasts and by measuring changes in cell viability and density on days 1, 30, 60 and 90 following acclimation. Cell viability and density were also measured in 7. ppt cultures acclimated to each temperature and then transferred to 3.5. ppt. The largest decreases in cell viability occurred only with combined low temperature and salinity, indicating that there is clearly a synergistic effect. The largest decreases in cell viability occurred only with both low temperature and salinity after 30. days (3.5. ppt, 2 ??C: 0% viability), 60. days (3.5. ppt, 10 ??C: 0% viability) and 90. days (7. ppt, 2 ??C: 0.6 ?? 0.7%; 7. ppt, 10 ??C: 0.2 ?? 0.2%). ?? 2010 .

Journal of Invertebrate Pathology↗
USGS2021

In vitro effects-based method and water quality screening model for use in pre- and post-distribution treated waters

Recent urban public water supply contamination events emphasize the importance of screening treated drinking water quality after distribution. In vitro bioassays, when run concurrently with analytical chemistry methods, are effective tools to evaluating the efficacy of water treatment processes and water quality. We tested 49 water samples representing the Chicago Department of Water Management service areas for estrogen, (anti)androgen, glucocorticoid receptor-activating contaminants and cytotoxicity. We present a tiered screening approach suitable to samples with anticipated low-level activity and initially tested all extracts for statistically identifiable endocrine activity; performing a secondary dilution-response analysis to determine sample EC 50 and biological equivalency values (BioEq). Estrogenic activity was detected in untreated Lake Michigan intake water samples using mammalian (5/49; median: 0.21 ng E2Eq/L) and yeast cell (5/49; 1.78 ng E2Eq/L) bioassays. A highly sensitive (anti)androgenic activity bioassay was applied for the first time to water quality screening and androgenic activity was detected in untreated intake and treated pre-distribution samples (4/49; 0.93 ng DHTEq/L). No activity was identified above method detection limits in the yeast androgenic, mammalian anti-androgenic, and both glucocorticoid bioassays. Known estrogen receptor agonists were detected using HPLC/MS-MS (estrone: 0.72-1.4 ng/L; 17α-estradiol: 1.3-1.5 ng/L; 17β-estradiol: 1.4 ng/L; equol: 8.8 ng/L), however occurrence did not correlate with estrogenic bioassay results. Many studies have applied bioassays to water quality monitoring using only relatively small samples sets often collected from surface and/or wastewater effluent. However, to realistically adapt these tools to treated water quality monitoring, water quality managers must have the capacity to screen potentially hundreds of samples in short timeframes. Therefore, we provided a tiered screening model that increased sample screening speed, without sacrificing statistical stringency, and detected estrogenic and androgenic activity only in pre-distribution Chicago area samples.

Illinois, Indiana↗
USGS2023

SARS-CoV-2 utilization of ACE2 from different bat species allows for virus entry and replication in vitro

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is believed to have a zoonotic origin with bats suspected as a natural host. In this work, we individually express the ACE2 of seven bat species including, little brown, great roundleaf, Pearson's horseshoe, greater horseshoe, Brazilian free-tailed, Egyptian rousette, and Chinese rufous horseshoe in DF1 cells and determine their ability to support attachment and replication of SARS-CoV-2 viruses. We demonstrate that the ACE2 receptor of all seven species made DF1 cells permissible to SARS-CoV-2. The level of virus replication differed between bat species and variants tested. The Wuhan lineage SARS-CoV-2 virus replicated to higher titers than either variant virus tested. All viruses tested grew to higher titers in cells expressing the human ACE2 gene compared to a bat ACE2. This study provides a practical in vitro method for further testing of animal species for potential susceptibility to current and emerging SARS-CoV-2 viruses.

Virology↗
USGS2026

Comparative screening of private, public, and bottled drinking water in vitro bioactivity

This study compares in vitro bioactivity profiles of extracts from private tapwater (51 samples), public tapwater (143 samples), and bottled water (31 samples), using high-throughput, multiplex, transcription factor screening. Of 48 biological end points tested, 25 showed significant (≥50% above the field blank) activity. Frequently detected (≥10% of samples) bioactivities (in decreasing order) included xenobiotic metabolism (pregnane X receptor [ PXR ], aryl hydrocarbon receptor [ AhR ]), antioxidant response (antioxidant response element-binding nuclear factor erythroid 2-related factor 2 [ NRF2 ], activator protein 1 [ AP-1 ]), endocrine signaling (estrogen receptor [ ER ], peroxisome proliferator-activated receptor [ PPAR ]), and metals response (metals response element [ MRE ]). Significant bioactivities were observed across all drinking water supplies, with some statistical differences identified. Bioactivities were moderately to strongly correlated with several individual exposure and corresponding benchmark- or activity-weighted metrics, particularly for disinfection byproducts. Significant (α = 0.05) but weak correlations between measured bioactivity resemblance patterns and those of the inorganic–organic exposure, toxicity-quotient (TQ), and exposure-activity-ratio (EAR) resemblance matrices suggest that key drivers of observed drinking water bioactivity were not captured by the extensive, targeted exposure assessment. Results highlight the need for effects-based monitoring combined with improved exposure analysis to better assess health risks from low-level contaminant mixtures in drinking water.

ES&T Water↗
USGS2006

Temperature comparisons for antibody production in vitro by plaque-forming cells from trout Salmo gairdneri (Richardson), and mice

Anterior kidney and splenic cells were taken from rainbow trout and splenic cells from BALB/c mice immunized with a T-dependent (sheep red blood cells) or T-independent (DNP-Ficoll) antigen. The cells were incubated at different temperatures in Jerne plaque assays (direct or passive haemolytic plaque assays). The optimum numbers of in vitro plaque-forming cells (PFC) after incubation with homologous complement were directly correlated with normal body temperatures of the respective species. The optimum incubation temperature was 37°C for mouse cells and 10°C for fish cells. Incubation of mouse cells at lower temperatures of 30, 20, 10, 4 or 0°C appeared to yield a direct line reduction in numbers of PFC. Trout cells developed significantly fewer PFC at 4 and 20°C and none at 30°C or above; however, significant numbers still appeared at 0°C. More PFC per million white blood cells were obtained from the anterior kidney; however, related to temperatures, no differences in development of numbers of PFC could be seen between the spleen and anterior kidney cells of trout. When the incubation time was lengthened for both trout and mouse cells held at low temperatures, the numbers of PFC approached those of the cells incubated at the optimum temperatures for 10 h.

Journal of Fish Biology↗
USGS2017

In-vitro replication of Chelonid herpesvirus 5 in organotypic skin cultures from Hawaiian green turtles (Chelonia mydas)

Fibropapillomatosis (FP) is a tumor disease of marine turtles associated with Chelonid herpesvirus 5 (ChHV5) that has historically been refractory to growth in tissue culture. Here, we show for the first time de novo formation of ChHV5-positive intranuclear inclusions in cultured green turtle cells, which is indicative for active lytic replication of the virus. The minimal requirements to achieve lytic replication in cultured cells included 1) either in-vitro culturing of ChHV5-positive tumor biopsies (plugs) or organotypic cultures (rafts) consisting of ChHV5-positive turtle fibroblasts in collagen rafts seeded with turtle keratinocytes and 2) keratinocyte maturation induced by raising raft or biopsy cultures to the air-liquid interface. Virus growth was confirmed by detailed electron microscopic studies revealing intranuclear sun-shaped capsid factories, tubules, various stages of capsid formation, nuclear export by budding into the perinuclear space, tegumentation, and envelopment to complete de novo virus production. Membrane synthesis was also observed as a sign for active viral replication. Interestingly, cytoplasmic particles became associated with keratin filaments, a feature not seen in conventional monolayer cell cultures where most studies of herpesvirus replication have been performed. Our findings draw a rich and realistic picture of ChHV5 replication in cells derived from its natural host and may be crucial not only to better understand ChHV5 circulation but also to eventually complete Koch's postulates for FP. Moreover, the principles described here may serve as model to culture other viruses that are resistant to replication in conventional cell culture.

Hawai'i↗
USGS2024

Evaluation of in vitro treatments against the causative agent of Diadema antillarum scuticociliatosis (DaSc)

ABSTRACT: In the 1980s, a mass die-off of the long-spined sea urchin Diadema antillarum occurred on Florida and Caribbean coral reefs. D. antillarum populations largely did not recover, and in 2022, remaining populations experienced another mass mortality event. A ciliate most similar to Philaster apodigitiformis was identified as the causative agent of the 2022 event, which was named D. antillarum scuticociliatosis (DaSc). Here, we investigated possible treatments for this pathogen. We tested the efficacy of 10 compounds at final concentrations of 100, 50, 25, 12.5, 6.25, and 3.13 µM, or a 10-fold serial dilution series, against ciliates cultured from an infected D. antillarum specimen. Of the tested compounds, 8 induced 100% ciliate mortality at some dose after 24 h. The most effective (defined as those requiring the lowest dose to induce 100% ciliate mortality) were quinacrine and tomatine (both effective at 12.5 µM), followed by furaltadone and plumbagin (25 µM), bithionol sulfoxide and 2’4’ dihydroxychalcone (50 µM), and oxyclozanide and carnidazole (100 µM). Toltrazuril and a commercially available anticiliate product containing naphthoquinones were not effective at any dose tested. Shortened (15 min) time trials were performed using ciliate cultures reared in natural seawater to better reflect natural environmental conditions, and revealed that 2 of the compounds (quinacrine and tomatine) induced 100% ciliate mortality at 100 µM, with tomatine also effective at 50 µM. This study identified several treatments effective against the causative agent of DaSc in vitro , but their toxicity and utility in vivo remain unknown.

Diseases of Aquatic Organisms↗
USGS2011

In vitro and in vivo antioxidant activity of a water-soluble polysaccharide from dendrobium denneanum

The water-soluble crude polysaccharide (DDP) obtained from the aqueous extracts of the stem of Dendrobium denneanum through hot water extraction followed by ethanol precipitation , was found to have an average molecular weight (Mw) of about 484.7 kDa. Monosaccharide analysis revealed that DDP was composed of arabinose, xylose, mannose, glucose and galactose in a molar ratio of 1.00:2.66:8.92:34.20:10.16. The investigation of antioxidant activity both in vitro and in vivo showed that DDP is a potential antioxidant.

Molecules↗
USGS1994

In vitro growth of the bacterial kidney disease organism Renibacterium salmoninarum on a nonserum, noncharcoal-based "homospecies-metabolite" medium

Laboratory and field trials were conducted to evaluate in vitro growth of Renibacterium salmoninarum in media without serum or charcoal. Growth of this bacterium, the cause of bacterial kidney disease (BKD) in salmonids, is accelerated by addition of a growth enhancing “metabolite” of unknown composition to KDM2 medium, the medium commonly used for isolation of R. salmoninarum . KDM2 medium supplemented with greater than 1% (v/v) metabolite enhanced growth even without addition of either serum or charcoal. Medium containing 5% metabolite (denoted Five-M) allowed optimal growth in laboratory studies and was further evaluated as a primary plating medium for recovery of the bacterium isolated from chinook salmon ( Oncorhynchus tshawytscha ) exhibiting clinical BKD. Recovery rates of R. salmoninarum using Five-M medium were 4% and 36% higher, respectively, than comparable rates using a serum-based medium for the two salmon populations evaluated. Five-M medium is an effective, inexpensive alternative to serum-based or charcoal-based media.

Journal of Wildlife Diseases↗
USGS1998

Fish thymocyte viability, apoptosis and necrosis: In-vitro effects of organochlorine contaminants

The thymus is believed to be a central component of haematopoiesis and immune function in teleosts. Hence, chemically-elicited adverse effects to the thymus may result in immunomodulation and organ dysfunction. The objective of this research was to assess the levels of active (apoptotic) and passive (necrotic) cell death in untreated and organochlorine treated fish thymocytes. Lake trout ( Salvelinus namaycush ) thymocytes were challenged with Aroclor 1254 (concentration range 1·5–10·5 μg ml −1 ) and alpha, beta, gamma, delta isomers of hexachlorocyclohexane (concentration range 10–100 μ M ). The resulting maintenance or loss of viability was assessed by cytofluorometry (expression of phosphatidylserine and exclusion of propidium iodide) and confirmed with fluorescence microscopy. The results indicate that 20–60% of thymocytes in healthy fish undergo apoptosis, whereas thymocytes treated for 6–24 h with organochlorines exhibit increased levels of apoptotic cell death. This study demonstrates that given sufficient concentration, contact time and cellular receptors, organochlorines such as Aroclor 1254 and hexachloro-cyclohexanes may induce direct or indirect toxicity, altered functionality, or cell death to an organ important for fish immunocompetence.

Fish and Shellfish Immunology↗
USGS1999

Cloning, in Vitro expression, and novel phylogenetic classification of a channel catfish estrogen receptor

We obtained two channel catfish estrogen receptor (ccER) cDNA from liver of female fish using RT–PCR. The two fragments were identical in sequence except that the smaller one had an out-of-frame deletion in the E domain, suggesting the existence of ccER splice variants. The larger fragment was used to screen a cDNA library from liver of a prepubescent female. A cDNA was obtained that encoded a 581-amino-acid ER with a deduced molecular weight of 63.8 kDa. Extracts of COS-7 cells transfected with ccER cDNA bound estrogen with high affinity ( K d = 4.7 nM) and specificity. Maximum parsimony and Neighbor Joining analyses were used to generate a phylogenetic classification of ccER on the basis of 18 full-length ER sequences. The tree suggested the existence of two major ER branches. One branch contained two clearly divergent clades which included all piscine ER (except Japanese eel ER) and all tetrapod ERα, respectively. The second major branch contained the eel ER and the mammalian ERβ. The high degree of divergence between the eel ER and mammalian ERβ suggested that they also represent distinct piscine and tetrapod ER. These data suggest that ERα and ERβ are present throughout vertebrates and that these two major ER types evolved by duplication of an ancestral ER gene. Sequence alignments with other members of the nuclear hormone receptor superfamily indicated the presence of 8 amino acids in the E domain that align exclusively among ER. Four of these amino acids have not received prior research attention and their function is unknown. The novel finding of putative ER splice variants in a nonmammalian vertebrate and the novel phylogenetic classification of ER offer new perspectives in understanding the diversification and function of ER.

General and Comparative Endocrinology↗