| aegyptianella ranarum sp. n. (rickettsiales, anaplasmataceae): ultrastructure and prevalence in frogs from ontario. | aegyptianella ranarum sp. n. (rickettsiales, anaplasmataceae) was recorded from bullfrogs (rana catesbeiana shaw), green frogs (rana clamitans latreille) and mink frogs (rana septentrionalis baird) from five sites in southern ontario. the rickettsia occurs within membrane-bound vacuoles in the cytoplasm of erythrocytes with up to 120 organisms in mature inclusions. the pattern of replication of a. ranarum in host erythrocytes and its prevalence over a 3-yr period in frogs from algonquin park, on ... | 1987 | 3493355 |
| alteration of the anterior-posterior embryonic axis: the pattern of gastrulation in macrocephalic frog embryos. | the production of an enlarged head or macrocephaly in frog embryos can be achieved by interspecific hybridization or by injection of the contents of the germinal vesicle (gv), the large nucleus of immature oocytes, into the blastocoels of embryos before they gastrulate. the macrocephalic embryos have large suckers and their neural tubes are larger anteriorly but smaller posteriorly as compared to controls. this abnormal syndrome has previously been thought to arise as a result of an axial struct ... | 1985 | 4038389 |
| purification and characterization of antimicrobial peptides from the skin secretions of the mink frog (rana septentrionalis). | skin secretions were obtained from male, female, and juvenile specimens of the mink frog (rana septentrionalis) by electric stimulation and shown to contain 10 peptides that differentially inhibited the growth of microorganisms. the elution profiles of secretions from the three groups following reverse-phase hplc were almost identical indicating that there were no major sexual or developmental differences in chemical composition. four peptides of the brevinin-1 family, with potent antimicrobial ... | 2004 | 15556063 |
| antimicrobial properties of two purified skin peptides from the mink frog (rana septentrionalis) against bacteria isolated from the natural habitat. | numerous peptides exhibiting antimicrobial properties have been isolated from the skins of many amphibian species. these peptides offer an innate chemical defense system against various microbial agents that exist in the amphibian's environment. amphibian skin peptides are typically tested for antimicrobial activity against microbial strains that are pathogenic to humans, but not on potential pathogenic or opportunistic bacteria that exist in the organism's habitat. two peptides, a brevinin-2-re ... | 2007 | 17499556 |
| antimicrobial properties of brevinin-2-related peptide and its analogs: efficacy against multidrug-resistant acinetobacter baumannii. | brevinin-2 related peptide (b2rp; giwdtiksmg(10)kvfagkilqn(20)l.nh(2)), first isolated from skin secretions of the mink frog lithobates septentrionalis, shows broad-spectrum antimicrobial activity but its therapeutic potential is limited by moderate hemolytic activity. the peptide adopts an alpha-helical conformation in a membrane-mimetic solvent but amphipathicity is low. increasing amphipathicity together with hydrophobicity by the substitutions lys(16)-->leu and lys(16)-->ala increased hemoly ... | 2009 | 19793185 |
| blood parasites of amphibians from algonquin park, ontario. | during a 5 wk period beginning may 25, 1983, 329 amphibians, which included specimens of rana catesbeiana shaw, rana clamitans latreille, rana septentrionalis baird, rana sylvatica leconte, hyla crucifer wied, bufo americanus holbrook, and plethodon cinereus green, from lake sasajewun, algonquin park, ontario, canada were examined for blood parasites. the prevalences of species of trypanosoma, haemogregarina, lankesterella, babesiasoma, and thrombocytozoons in these amphibians were determined. t ... | 1984 | 6492319 |
| micelle bound structure and dna interaction of brevinin-2-related peptide, an antimicrobial peptide derived from frog skin. | brevinin-2-related peptide (br-ii), a novel antimicrobial peptide isolated from the skin of frog, rana septentrionalis, shows a broad spectrum of antimicrobial activity with low haemolytic activity. it has also been shown to have antiviral activity, specifically to protect cells from infection by hiv-1. to understand the active conformation of the br-ii peptide in membranes, we have investigated the interaction of br-ii with the prokaryotic and eukaryotic membrane-mimetic micelles such as sodium ... | 2014 | 25044683 |
| peptidomic analysis of skin secretions from rana heckscheri and rana okaloosae provides insight into phylogenetic relationships among frogs of the aquarana species group. | the members of the aquarana (or rana catesbeiana species group) form a monophyletic group comprising seven species: r. catesbeiana, rana clamitans, rana grylio, rana virgatipes, rana septentrionalis, rana heckscheri and rana okaloosae. previous work has led to structural characterization of the antimicrobial peptides present in electrically-stimulated skin secretions from the first five species listed and this study presents the primary structures of orthologs from the river frog r. heckscheri a ... | 2007 | 17005262 |
| ultrastructural, biochemical and biophysical properties of an erythrocytic virus of frogs from ontario, canada. | frog erythrocytic virus (fev), one of the largest icosahedral viruses, is enveloped, measures up to 450 nm in diameter, and contains double stranded dna. the virus is found in the cytoplasm of erythrocytes of rana catesbeiana, rana septentrionalis, and rana clamitans from algonquin park, ontario (canada). acidophilic inclusions in infected erythrocytes stained with giemsa's stain correspond to viroplasms from which fev buds and forms aggregates of virus particles as seen in the electron microsco ... | 1989 | 2810549 |
| prevalence of skeletal and eye malformations in frogs from north-central united states: estimations based on collections from randomly selected sites. | skeletal malformation rates for several frog species were determined in a set of randomly selected wetlands in the north-central usa over three consecutive years. in 1998, 62 sites yielded 389 metamorphic frogs, nine (2.3%) of which had skeletal or eye malformations. a subset of the original sites was surveyed in the following 2 yr. in 1999, 1,085 metamorphic frogs were collected from 36 sites and 17 (1.6%) had skeletal or eye malformations, while in 2000, examination of 1,131 metamorphs yielded ... | 2003 | 14567211 |
| a regional survey of malformed frogs in minnesota (usa) (minnesota malformed frogs). | in late 1995, school children discovered malformed frogs in a south central minnesota pond. press coverage resulted in numerous citizen reports of frog malformation across minnesota in 1996. after some initial site investigation, 3 affected frog sites and 4 nearby reference sites were selected for more detailed evaluation. field biologists made 89 visits to study sites beginning spring 1997 through fall 1999 to examine the number and type of frog malformations. over 5,100 leopard frogs (rana pip ... | 2003 | 12602621 |
| fatty acid composition of muscle tissue measured in amphibians living in radiologically contaminated and non-contaminated environments. | fatty acid composition was identified as a potential biological indicator of the effects of environmental exposure to radiological contaminants. this end point was measured in muscle tissues of mink frogs ( rana septentrionalis ) obtained from a radiologically contaminated pond and from a non-contaminated pond. it was also measured after the frogs obtained from both ponds were exposed to a 4 gy (60)co γ radiation dose delivered in vivo at a dose rate of approximately 8 gy/min. statistically sign ... | 2012 | 22799633 |
| ambient solar uv radiation causes mortality in larvae of three species of rana under controlled exposure conditions. | recent reports concerning the lethal effects of solar ultraviolet-b (uv-b) (290-320 nm) radiation on amphibians suggest that this stressor has the potential to impact some amphibian populations. in this study embryos and larvae of three anuran species, rana pipiens, rana clamitans and rana septentrionalis, were exposed to full-spectrum solar radiation and solar radiation filtered to attenuate uv-b radiation or uv-b and ultraviolet-a (uv-a) (290-380 nm) radiation to determine the effects of each ... | 2001 | 11547564 |
| effects of the synthetic estrogen ethinylestradiol on early life stages of mink frogs and green frogs in the wild and in situ. | estrogenic contaminants are known to disrupt growth and development in amphibians. field-based research is needed to elucidate their potential impacts on wild populations. hatch success, larval growth and development rates, and gonad development were examined in native amphibians exposed to low ng/l concentrations of 17alpha-ethinylestradiol (ee2) in a whole-lake addition experiment at the experimental lakes area, northwestern ontario, canada. egg masses were reared in situ in the ee2-amended la ... | 2005 | 16152976 |
| densities of mink frogs, rana septentrionalis, in new brunswick forest ponds sprayed with the insecticide fenitrothion. | | 1998 | 9484553 |
| environmentally induced limb malformations in mink frogs (rana septentrionalis). | in recent years, there has been an increase in the incidence of frog deformities throughout many of the northern states of north america. the most readily noticed malformations involve the hindlimbs of peri-metamorphic animals. we have analyzed skeletal preparations of metamorphosing mink frogs (rana septentrionalis) collected from a site in minnesota, in order to develop a better understanding of the possible causes. in this paper we describe the categories of abnormalities found at this site. ... | 1999 | 10404649 |