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Results: 1 to 7 of 7

Publication Record


Cyp27c1 Red-Shifts the Spectral Sensitivity of Photoreceptors by Converting Vitamin A1 into A2.
Enright JM, Toomey MB, Sato SY, Temple SE, Allen JR, Fujiwara R, Kramlinger VM, Nagy LD, Johnson KM, Xiao Y, How MJ, Johnson SL, Roberts NW, Kefalov VJ, Guengerich FP, Corbo JC
(2015) Curr Biol 25: 3048-57
MeSH Terms: Amphibian Proteins, Animals, Cytochrome P-450 Enzyme System, Infrared Rays, Photoreceptor Cells, Vertebrate, Rana catesbeiana, Transcriptome, Visual Perception, Vitamin A, Zebrafish, Zebrafish Proteins
Show Abstract · Added March 14, 2018
Some vertebrate species have evolved means of extending their visual sensitivity beyond the range of human vision. One mechanism of enhancing sensitivity to long-wavelength light is to replace the 11-cis retinal chromophore in photopigments with 11-cis 3,4-didehydroretinal. Despite over a century of research on this topic, the enzymatic basis of this perceptual switch remains unknown. Here, we show that a cytochrome P450 family member, Cyp27c1, mediates this switch by converting vitamin A1 (the precursor of 11-cis retinal) into vitamin A2 (the precursor of 11-cis 3,4-didehydroretinal). Knockout of cyp27c1 in zebrafish abrogates production of vitamin A2, eliminating the animal's ability to red-shift its photoreceptor spectral sensitivity and reducing its ability to see and respond to near-infrared light. Thus, the expression of a single enzyme mediates dynamic spectral tuning of the entire visual system by controlling the balance of vitamin A1 and A2 in the eye.
Copyright © 2015 Elsevier Ltd. All rights reserved.
0 Communities
1 Members
0 Resources
11 MeSH Terms
Effect of glucocorticoids on expression of cutaneous antimicrobial peptides in northern leopard frogs (Lithobates pipiens).
Tatiersky L, Rollins-Smith LA, Lu R, Jardine C, Barker IK, Clark ME, Caswell JL
(2015) BMC Vet Res 11: 191
MeSH Terms: Amphibian Proteins, Animals, Antimicrobial Cationic Peptides, Gene Expression Regulation, Glucocorticoids, Methylprednisolone, Rana pipiens, Skin
Show Abstract · Added April 18, 2017
BACKGROUND - Many species of frogs secrete cutaneous antimicrobial peptides that are capable of killing Batrachochytrium dendrobatidis. Some of these species are nonetheless susceptible to chytridiomycosis, suggesting that host factors causing dysregulation of this innate immune response may be important in pathogenesis. Since stresses, such as from environmental perturbations, are a potential cause of such dysregulation, this study investigated the effect of glucocorticoid on cutaneous gene expression of these antimicrobial peptides.
RESULTS - Northern leopard frogs (Lithobates pipiens) were injected with either the corticosteroid methylprednisolone or saline every 48 h. Norepinephrine-elicited cutaneous secretions were collected every 8 days for 40 days. Gene expression of antimicrobial peptides (brevinin-1P and ranatuerin-2P) in the cutaneous secretions was measured relative to the reference genes EF1-α and RPL8 using quantitative RT-PCR. Corticosteroid treatment was associated with a significant increase in brevinin-1P gene expression, which was most notable at 24-40 days of corticosteroid administration. Ranatuerin-2P expression followed a similar but non-significant trend.
CONCLUSION - This treatment protocol, including corticosteroid-administration and frequent norepinephrine-induced secretion, increased AMP gene expression in the skin of L. pipiens under these experimental conditions. The findings do not support the hypothesis that environmental stress predisposes frogs to chytridiomycosis by causing glucocorticoid-induced suppression of antimicrobial peptide defences.
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8 MeSH Terms
Inhibition of HIV infection by caerin 1 antimicrobial peptides.
VanCompernolle S, Smith PB, Bowie JH, Tyler MJ, Unutmaz D, Rollins-Smith LA
(2015) Peptides 71: 296-303
MeSH Terms: Amphibian Proteins, Antimicrobial Cationic Peptides, Dose-Response Relationship, Drug, HIV Infections, HIV-1, Humans, T-Lymphocytes
Show Abstract · Added April 18, 2017
The major mode of transmission of the human immunodeficiency virus (HIV) is by sexual intercourse. In the effort to halt the spread of HIV, one measure that holds great promise is the development of effective microbicides that can prevent transmission. Previously we showed that several amphibian antimicrobial peptides (AMPs) completely inhibit HIV infection of T cells while maintaining good viability of the T cell targets. These peptides also inhibited the transfer of HIV by dendritic cells (DCs) to T cells when added up to 8h after virus exposure. Here we report on the anti-HIV activity of 18 additional structurally related caerin 1 family peptides in comparison with our previous best candidate caerin 1.9. Nine peptides were equally effective or more effective in the inhibition of T cell infection and disruption of the HIV envelope as caerin 1.9. Of those nine peptides, three peptides (caerin 1.2, caerin 1.10, and caerin 1.20) exhibited excellent inhibition of HIV infectivity at low concentrations (12-25μM) and limited toxicity against target T cells and endocervical epithelial cells. There was a direct correlation between the effectiveness of the peptides in disruption of the viral envelope and their capacity to inhibit infection. Thus, several additional caerin 1 family peptides inhibit HIV infection have limited toxicity for vaginal epithelial cells, and would be good candidates for inclusion in microbicide formulations.
Copyright © 2015 Elsevier Inc. All rights reserved.
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1 Members
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7 MeSH Terms
Variations in the expressed antimicrobial peptide repertoire of northern leopard frog (Rana pipiens) populations suggest intraspecies differences in resistance to pathogens.
Tennessen JA, Woodhams DC, Chaurand P, Reinert LK, Billheimer D, Shyr Y, Caprioli RM, Blouin MS, Rollins-Smith LA
(2009) Dev Comp Immunol 33: 1247-57
MeSH Terms: Aeromonas hydrophila, Alleles, Amino Acid Sequence, Amphibian Proteins, Animals, Chytridiomycota, Genetic Variation, Genetics, Population, Microbial Viability, Molecular Sequence Data, Peptides, Ranidae, Skin, Staphylococcus epidermidis, United States
Show Abstract · Added March 10, 2014
The northern leopard frog (Rana pipiens or Lithobates pipiens) is historically found in most of the provinces of Canada and the northern and southwest states of the United States. In the last 50 years, populations have suffered significant losses, especially in the western regions of the species range. Using a peptidomics approach, we show that the pattern of expressed antimicrobial skin peptides of frogs from three geographically separated populations are distinct, and we report the presence of four peptides (brevinin-1Pg, brevinin-1Pl, ranatuerin-2Pb, and ranatuerin-2Pc) that have not previously been found in skin secretions. The differences in expressed peptides reflect differences in the distribution of alleles for the newly described Brevinin1.1 locus in the three populations. When enriched peptide mixtures were tested for their ability to inhibit growth of the pathogenic amphibian chytrid (Batrachochytrium dendrobatidis), peptides from Minnesota or Vermont frogs were more effective that peptides from Michigan frogs. Four of the purified peptides were tested for their ability to inhibit growth of two bacterial pathogens (Aeromonas hydrophila and Staphylococcus epidermidis) and B. dendrobatidis. Three of the four were effective inhibitors of B. dendrobatidis and S. epidermidis, but none inhibited A. hydrophila. We interpret these differences in expression and activity of antimicrobial peptides as evidence to suggest that each population may have been selected to express a suite of peptides that reflects current and past encounters with skin microbes.
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2 Members
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15 MeSH Terms
The role of amphibian antimicrobial peptides in protection of amphibians from pathogens linked to global amphibian declines.
Rollins-Smith LA
(2009) Biochim Biophys Acta 1788: 1593-9
MeSH Terms: Amino Acid Sequence, Amphibian Proteins, Amphibians, Animals, Antimicrobial Cationic Peptides, Fungi, Molecular Sequence Data, Population Dynamics, Skin
Show Abstract · Added May 20, 2014
Amphibian species have experienced population declines and extinctions worldwide that are unprecedented in recent history. Many of these recent declines have been linked to a pathogenic skin fungus, Batrachochytrium dendrobatidis, or to iridoviruses of the genus Ranavirus. One of the first lines of defense against pathogens that enter by way of the skin are antimicrobial peptides synthesized and stored in dermal granular glands and secreted into the mucus following alarm or injury. Here, I review what is known about the capacity of amphibian antimicrobial peptides from diverse amphibians to inhibit B. dendrobatidis or ranavirus infections. When multiple species were compared for the effectiveness of their in vitro antimicrobial peptides defenses against B. dendrobatidis, non-declining species of rainforest amphibians had more effective antimicrobial peptides than species in the same habitat that had recently experienced population declines. Further, there was a significant correlation between the effectiveness of the antimicrobial peptides and resistance of the species to experimental infection. These studies support the hypothesis that antimicrobial peptides are an important component of innate defenses against B. dendrobatidis. Some amphibian antimicrobial peptides inhibit ranavirus infections and infection of human T lymphocytes by the human immunodeficiency virus (HIV). An effective antimicrobial peptide defense against skin pathogens appears to depend on a diverse array of genes expressing antimicrobial peptides. The production of antimicrobial peptides may be regulated by signals from the pathogens. However, this defense must also accommodate potentially beneficial microbes on the skin that compete or inhibit growth of the pathogens. How this delicate balancing act is accomplished is an important area of future research.
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1 Members
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9 MeSH Terms
Structural diversity in the catecholamine transporter gene family: molecular cloning and characterization of an L-epinephrine transporter from bullfrog sympathetic ganglia.
Blakely RD, Apparsundaram S
(1998) Adv Pharmacol 42: 206-10
MeSH Terms: Amphibian Proteins, Animals, Base Sequence, Binding, Competitive, Carrier Proteins, Cloning, Molecular, Conserved Sequence, Dopamine Uptake Inhibitors, Epinephrine, Ganglia, Sympathetic, Genetic Variation, HeLa Cells, Humans, Kinetics, Models, Structural, Multigene Family, Neurons, Norepinephrine, Protein Structure, Secondary, Rana catesbeiana, Recombinant Proteins, Transfection
Added July 10, 2013
1 Communities
1 Members
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22 MeSH Terms
Molecular cloning and characterization of an L-epinephrine transporter from sympathetic ganglia of the bullfrog, Rana catesbiana.
Apparsundaram S, Moore KR, Malone MD, Hartzell HC, Blakely RD
(1997) J Neurosci 17: 2691-702
MeSH Terms: Amino Acid Sequence, Amphibian Proteins, Animals, Base Sequence, Carrier Proteins, Cattle, Cloning, Molecular, Conserved Sequence, DNA Primers, Dopamine Plasma Membrane Transport Proteins, Epinephrine, Ganglia, Sympathetic, HeLa Cells, Humans, Kinetics, Membrane Glycoproteins, Membrane Transport Proteins, Mice, Molecular Sequence Data, Nerve Tissue Proteins, Norepinephrine Plasma Membrane Transport Proteins, Organ Specificity, Polymerase Chain Reaction, Rana catesbeiana, Rats, Recombinant Proteins, Sequence Homology, Amino Acid, Serotonin Plasma Membrane Transport Proteins, Symporters, Transfection
Show Abstract · Added July 10, 2013
Chemical signaling by dopamine (DA) and L-norepinephrine (L-NE) at synapses is terminated by uptake via specialized presynaptic transport proteins encoded by the DA transporter (DAT) and L-NE transporter (NET) genes, respectively. In some vertebrate neurons, particularly the sympathetic neurons of amphibians, L-NE is converted to L-epinephrine (L-Epi, adrenaline) and released as the primary neurotransmitter. Although evidence exists for a molecularly distinct L-Epi transporter (ET) in the vertebrate brain and peripheral nervous system, a transporter specialized for extracellular L-Epi clearance has yet to be identified. To pursue this issue, we cloned transporter cDNAs from bullfrog (Rana catesbiana) paravertebral sympathetic ganglia and characterized functional properties via heterologous expression in non-neuronal cells. A cDNA of 2514 bp (fET) was identified for which the cognate 3.1 kb mRNA is highly enriched in frog sympathetic ganglia. Sequence analysis of the fET cDNA reveals an open reading frame coding for a protein of 630 amino acids. Inferred fET protein sequence bears 75, 66, and 48% amino acid identity with human NET, DAT, and the 5-hydroxytryptamine transporter (SERT), respectively. Transfection of fET confers Na+- and Cl--dependent catecholamine uptake in HeLa cells. Uptake of [3H]-L-NE by fET is inhibited by catecholamines in a stereospecific manner. L-Epi and DA inhibit fET-mediated [3H]-L-NE uptake more potently than they inhibit [3H]-L-NE uptake by human NET (hNET), whereas L-NE exhibits equivalent potency between the two carriers. Moreover, fET exhibits a greater maximal velocity (Vmax) for the terminal products of catecholamine biosynthesis (L-Epi > L-NE > DA), unlike hNET, in which a Vmax rank order of L-NE > DA > L-Epi is observed. fET-mediated transport of catecholamines is sensitive to cocaine and tricyclic antidepressants, with antagonist potencies significantly correlated with hNET inhibitor sensitivity. Amino acid conservation and divergence of fET with mammalian catecholamine transporters help define residues likely to be involved in catecholamine recognition and translocation as well as blockade by selective reuptake inhibitors.
1 Communities
2 Members
0 Resources
30 MeSH Terms