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| | 1. |
2009 Feb 23 |
Kestrel-Prey Dynamic in a Mediterranean Region: The Effect of Generalist Predation and Climatic Factors
Fargallo, Martínez-Padilla, Viñuela, Blanco, Torre, Vergara, De Neve
PLoS ONE 2009 Feb 23;4(2). published online before print
Abstract
Most hypotheses on population limitation of small mammals and their predators come from studies carried out in northern latitudes, mainly in boreal ecosystems. In such regions, many predators specialize on voles and predator-prey systems are simpler compared to southern ecosystems where predator communities are made up mostly of generalists and predator-prey systems are more complex. Determining food limitation in generalist predators is difficult due to their capacity to switch to alternative prey when the basic prey becomes scarce.
[Pubmed: 19234618]
| | 2. |
2006 Apr |
Mammal and flea relationships in the Great Basin Desert: from H. J. Egoscue's collections.
Bossard RL
J. Parasitol. 2006 Apr;92(2):260-6.
Abstract
Host-parasite association among 58 flea species parasitizing 40 mammal species in the Great Basin Desert of the western United States was investigated. Increased flea species richness was correlated with larger geographic ranges and stable locomotion of hosts. Hosts from habitats of moderately low productivity (sage and grass) and of Peromyscus maniculatus size, 10-33 g, had the highest flea species richness. Larger hosts had fewer flea species, but fleas were more prevalent. Increased host species richness correlated with flea species eye size. Mammals clustered into 3 major and 1 minor ecological groups, and fleas clustered into 2 major groups among rodents, and 6 minor groups, forming 12 host-parasite biocenoses. Factors producing biocenoses were shared burrows of mice and rats; food chains of hares, rabbits, squirrels, and their predators; keystone mammals: Lagurus curtatus, Neotoma lepida, Ochotona princeps, and Spermophilus townsendii; keystone fleas: Megabothris abantis, and Meringis hubbardi; or host isolation, Neotoma cinerea with Oropsylla montana, Sorex vagrans with Corrodopsylla curvata, and Tadarida brasiliensis with Sternopsylla distincta. Although host relatedness accounted for flea prevalence, host sociality explained the presence or absence of mammal-flea relationships.
[Pubmed: 16729681]
| | 3. |
2006 Aug 04 |
Detoxification rates of wild herbivorous woodrats (Neotoma).
Dearing MD, Skopec MM, Bastiani MJ
Comp. Biochem. Physiol., Part A Mol. Integr. Physiol. 2006 Dec;145(4):419-22. Epub 2006 Aug 04.
Abstract
The detoxification systems of mammalian herbivores are thought to have evolved in response to the ingestion of plant secondary compounds. Specialist herbivores consume high quantities of secondary compounds and are predicted to have faster rates of Phase 1 detoxification compared to generalist herbivores. We tested this hypothesis by comparing the performances of a specialist (Neotoma fuscipes) and generalist (Neotoma lepida) herbivore using hypnotic state assays. Herbivores foraging in nature were live trapped and injected with hexobarbital (100 mg/kg). We measured the length of time in the hypnotic state as the time in which the animal was unable to right itself twice in 30 s. The specialist metabolized hexobarbital 1.7 times faster than the generalist (F(1, 19) = 9.31, P = 0.007) as revealed by its significantly shorter time spent in the hypnotic state (56+/-9 min vs. 87+/-8 min, respectively). The results are consistent with the hypothesis that specialists have faster rates of Phase 1 detoxification. This is the first evaluation of the detoxification capability of mammalian herbivores foraging under natural conditions. Hypnotic state assays have broad potential applications to the study of vertebrate-plant interactions.
[Pubmed: 16962347]
| | 4. |
2004 Jul |
Detection and characterization of Borrelia bissettii in rodents from the central California coast.
Vredevoe LK, Stevens JR, Schneider BS
J. Med. Entomol. 2004 Jul;41(4):736-45.
Abstract
This is the first report of Borrelia burgdorferi sensu lato in rodents from San Luis Obispo county, with most isolates obtained from a previously unreported host, Neotoma lepida Thomas. B. burgdorferi sensu lato was identified in seven rodent species, including the California vole, Microtus californicus Peale; dusky-footed woodrat, Neotoma fuscipes Baird; desert woodrat, Neotoma lepida Thomas; brush mouse, Peromyscus boylii Baird; California mouse, Peromyscus californicus Gambel; deer mouse, Peromyscus maniculatus Wagner; and western harvest mouse, Reithrodontomys megalotis Baird. Ear punch biopsies were cultured in BSK-H medium from 179 rodents trapped at six different study sites. Overall, prevalence of rodent infection was 44/179 (24.6%), with 34 of these isolates from N. lepida. Spirochete isolates were obtained from rodents at all study sites, indicating widespread prevalence of B. burgdorferi sensu lato across rodent species and habitats. Nucleotide sequences for 14 of these isolates have been submitted to GenBank. Isolates from three N. lepida and one P. boylii had identical flagellin gene sequences, and phylogenetic analysis placed these spirochetes in B. burgdorferi sensu lato group DN127, now known as B. bissettii Postic, Marti Ras, Lane, Hendson & Baranton. Additional sequencing of the intergenic spacer regions between the 5S and 23S ribosomal genes was performed on three of these isolates. Phylogenetic analysis separated these isolates into two clusters that grouped with Colorado or California isolates. The role of B. bissettii and related species other than B. burgdorferi sensu stricto Johnson, Schmid, Hyde, Steigerwalt & Brenner as human pathogens in the United States warrants further investigation.
[Pubmed: 15311469]
| | 5. |
2009 Jun 11 |
Ectomycorrhizal community structure in a healthy and a Phytophthora-infected chestnut (Castanea sativa Mill.) stand in central Italy.
Blom JM, Vannini A, Vettraino AM, Hale MD, Godbold DL
Mycorrhiza. 2009 Jun 11; [Epub ahead of print]
Abstract
Ink disease caused by Phytophthora cambivora is a major disease of sweet chestnut (Castanea sativa). In two C. sativa stands in central Italy, one (Montesanti) that is infected with P. cambivora and the trees showing symptoms of ink disease and another healthy stand (Puzzella), the ectomycorrhizal (ECM) community structure was investigated. On the roots of the surviving trees of the diseased stand, 29 different ECM species were determined compared to 23 in the healthy stand. Eleven ECM species were common to both stands; however, a number of species were unique to one of the stands. Cenococcum geophilum was dominant at both sites, but the percentage colonisation was much higher at Montesanti (40.8%) compared to Puzzella (27.2%). There was a switch in species from Russula vesca, Russula lepida and Russula azurea at Puzzella to Russula nigricans, R. lepida and Russula delica at Montesanti. Both R. vesca and R. azurea were found only at the Puzzella site. At the diseased site, the ECMs formed had a smaller root tip diameter, and the ECM at the healthy site had more abundant extramatrical hyphae.
[Pubmed: 19517140]
| | 6. |
2009 Apr 07 |
Expression of biotransformation genes in woodrat (Neotoma) herbivores on novel and ancestral diets: identification of candidate genes responsible for dietary shifts.
Magnanou E, Malenke JR, Dearing MD
Mol. Ecol. 2009 Jun;18(11):2401-14. Epub 2009 Apr 07.
Abstract
The ability of herbivores to switch diets is thought to be governed by biotransformation enzymes. To identify potential biotransformation enzymes, we conducted a large-scale study on the expression of biotransformation enzymes in herbivorous woodrats (Neotoma lepida). We compared gene expression in a woodrat population from the Great Basin that feeds on the ancestral diet of juniper to one from the Mojave Desert that putatively switched from feeding on juniper to feeding on creosote. Juniper and creosote have notable differences in secondary chemistry, and thus, should require different biotransformation enzymes for detoxification. Individuals from each population were fed juniper and creosote diets separately. After the feeding trials, hepatic mRNA was extracted and hybridized to laboratory rat microarrays. Hybridization of woodrat samples to biotransformation probes on the array was 87%, resulting in a total of 224 biotransformation genes that met quality control standards. Overall, we found large differences in expression of biotransformation genes when woodrats were fed juniper vs. creosote. Mojave woodrats had greater expression of 10x as many biotransformation genes as did Great Basin woodrats on a creosote diet. We identified 24 candidate genes that may be critical in the biotransformation of creosote toxins. Superoxide dismutase, a free radical scavenger, was also expressed to a greater extent by the Mojave woodrats and may be important in controlling oxidative damage during biotransformation. The results are consistent with the hypothesis that biotransformation enzymes limit diet switching and that woodrats in the Mojave have evolved a unique strategy for the biotransformation of creosote toxins.
[Pubmed: 19389177]
| | 7. |
2009 May 5 |
Hormonal and cell division analyses in Watsonia lepida seedlings.
Ascough GD, Novák O, Pěnčík A, Rolčík J, Strnad M, Erwin JE, Van Staden J
J. Plant Physiol. 2009 May 5; [Epub ahead of print]
Abstract
The regeneration ability, cell division activity, auxin and cytokinin content of seedling regions and hypocotyl subsections of Watsonia lepida were studied. A total of 21 different cytokinins or conjugates were found in seedlings, with the highest cytokinin content in meristematic regions (root and shoot apical meristems). The greatest contribution to the cytokinin pool came from the biologically inactive cZRMP, suggesting that significant de novo synthesis was occurring. Five different auxins or conjugates were detected, being concentrated largely in the shoot apical meristem and leaves, IAA being the most abundant. Analysis of hypocotyl subsections (C1-C4) revealed that cell division was highest in subsection C2, although regeneration in vitro was significantly lower than in subsection C1. Anatomically, subsection C1 contains the apical meristem, and hence has meristematic cells that are developmentally plastic. In contrast, subsection C2 has cells that have recently exited the meristem and are differentiating. Despite high rates of cell division, cells in subsection C2 appear no longer able to respond to cues that promote proliferation in vitro. Auxin and cytokinin analyses of these subsections were conducted. Possibly, a lower overall cytokinin content, and in particular the free-base cytokinins, could account for this observed difference.
[Pubmed: 19423185]
| | 8. |
|
"Pharm-ecology" of diet shifting: biotransformation of plant secondary compounds in creosote (Larrea tridentata) by a woodrat herbivore, Neotoma lepida.
Haley SL, Lamb JG, Franklin MR, Constance JE, Dearing MD
Physiol. Biochem. Zool.;81(5):584-93.
Abstract
Diet switching in mammalian herbivores may necessitate a change in the biotransformation enzymes used to process plant secondary compounds (PSCs). We investigated differences in the biotransformation system in the mammalian herbivore, Neotoma lepida, after a radical shift in diet and secondary compound composition. Populations of N. lepida in the Mojave Desert have evolved over the past 10,000 years to feed on creosote (Larrea tridentata) from an ancestral state of consuming juniper (Juniperus osteosperma). This dietary shift represents a marked change in the dietary composition of PSCs in that creosote leaves are coated with phenolic resin, whereas juniper is high in terpenes but lacks phenolic resin. We quantified the enzyme activity of five major groups of biotransformation enzymes (cytochrome P450s, NAD(P)H:quinone oxidoreductase, glutathione conjugation, sulfation, and glucuronidation) recognized for their importance to mammalian biotransformation for the elimination of foreign compounds. Enzyme activities were compared between populations of Mojave and Great Basin woodrats fed control and creosote diets. In response to creosote, the Mojave population had greater levels of cytochrome P450s (CYP2B, CYP1A) and glutathione conjugation liver enzymes compared with the Great Basin population. Our results suggest that elevated levels of cytochrome P450s and glutathione conjugation enzymes in the Mojave population may be the underlying biotransformation mechanisms that facilitate feeding on creosote.
[Pubmed: 18752424]
| | 9. |
|
An oak (Quercus agrifolia) specialist (Neotoma macrotis) and a sympatric generalist (Neotoma lepida) show similar intakes and digestibilities of oak.
Skopec MM, Haley S, Torregrossa AM, Dearing MD
Physiol. Biochem. Zool.;81(4):426-33.
Abstract
Dietary specialization is thought to be rare in mammalian herbivores as a result of either a limitation in their detoxification system to metabolize higher doses of plant secondary compounds or deficiencies in nutrients present in a diet composed of a single species of plant. Neotoma macrotis is an oak specialist, whereas Neotoma lepida is a dietary generalist when sympatric with N. macrotis. We hypothesized that N. macrotis would have a higher tolerance for and digestibility of oak. We determined the two species' tolerances for oak by feeding them increasing concentrations of ground oak leaves until they could no longer maintain body mass. The highest concentration on which both species maintained body mass was 75% oak. There were no differences between the species in their abilities to digest dry matter, nitrogen, or fiber in the oak diets. The species' similar tolerances for oak were probably due to their similar abilities to digest and potentially assimilate the ground oak leaves.
[Pubmed: 18544017]
| | 10. |
2007 Oct 11 |
Xenobiotic metabolism of plant secondary compounds in oak (Quercus agrifolia) by specialist and generalist woodrat herbivores, genus Neotoma.
Haley SL, Lamb JG, Franklin MR, Constance JE, Dearing MD
J. Chem. Ecol. 2007 Nov;33(11):2111-22. Epub 2007 Oct 11.
Abstract
The challenge of consuming plant compounds that are recognized to have toxic physiological effects is an unavoidable consequence of an herbivorous diet and requires mechanisms to metabolize and eliminate them after consumption. We took a pharmacological approach to understanding how an oak (Quercus agrifolia) specialist (Neotoma macrotis) and generalist (N. lepida) herbivores process the same dietary toxins. Oak contains polyphenolic compounds considered toxic to most other mammals. N. macrotis includes up to 85% of oak in their diet. N. lepida includes oak as a portion of the diet but is considered a generalist in areas where sympatric with N. macrotis. Xenobiotic metabolizing enzyme activities of N. macrotis and N. lepida were investigated after animals were fed a 70% oak diet and a toxin-free control diet. Biotransformation activities of five major enzymes [cytochrome P450s (CYP), NAD(P)H/quinone oxidoreductase (QOR), UDP-glucuronosyltransferase (UGT), sulfotransferase (SULT), and glutathione S-transferase (GST)] and three specific CYP isozymes (CYP1A, CYP2B, and CYP3A) were investigated. The results indicate that, with the exception of CYP2B induction, N. macrotis and N. lepida enzyme activities are not changed by an oak diet. The major differences in enzyme activities were constitutive. The specialist, N. macrotis, had higher constitutive activity of QOR, UGT, and GST. The generalist, N. lepida, had higher constitutive activity levels of CYP1A and SULT.
[Pubmed: 17929091]
| | 11. |
|
Aorto-enteric fistula: CT findings.
Mylona S, Ntai S, Pomoni M, Kokkinaki A, Lepida N, Thanos L
Abdom Imaging.;32(3):393-7.
Abstract
The objective of this pictorial essay is to present the different CT findings encountered in patients with aorto-enteric fistulas (AEFs). An AEF is a rare and sometimes disastrous occurrence, responsible for intermittent or massive gastrointestinal hemorrhage and hematemesis. CT provides fast and effective evaluation in hemodynamically stable patients suspected of having an AEF.
[Pubmed: 17021648]
| | 12. |
2006 Dec |
Assessment of mercury concentrations in small mammals collected near Las Vegas, Nevada, USA.
Gerstenberger SL, Cross CL, Divine DD, Gulmatico ML, Rothweiler AM
Environ. Toxicol. 2006 Dec;21(6):583-9.
Abstract
Mercury concentrations in liver and hair tissue were determined for five species of small mammals captured near Las Vegas, Nevada, USA. These data were then used to evaluate the suitability of using hair as a noninvasive technique for determining body burdens of mercury. A total of 104 small mammals were captured and analyzed; four main species were examined and included: Dipodomys merriami, Chaetodipus penicillatus, Peromyscus eremicus, and Neotoma lepida. Mean mercury concentrations were highest in N. lepida, followed by D. merriami, C. penicillatus, and P. eremicus respectively. Positive associations were found between hair and liver taken from D. merriami (r = 0.647) and C. penicillatus (r = 0.533) indicating that hair may be a suitable indicator of body burdens in these two species.
[Pubmed: 17091502]
| | 13. |
2005 Oct 27 |
Plant secondary metabolites alter the feeding patterns of a mammalian herbivore (Neotoma lepida).
Sorensen JS, Heward E, Dearing MD
Oecologia. 2005 Dec;146(3):415-22. Epub 2005 Oct 27.
Abstract
Mammalian herbivores are predicted to regulate concentrations of ingested plant secondary metabolites (PSMs) in the blood by modifying the size and frequency of feeding bouts. It is theorized that meal size is limited by a maximum tolerable concentration of PSMs in the blood, such that meal size is predicted to decrease as PSM concentration increases. We investigated the relationship between PSM concentration in the diet and feeding patterns in the herbivorous desert woodrat (Neotoma lepida) fed diets containing phenolic resin extracted from creosote bush (Larrea tridentata). Total daily intake, meal size and feeding frequency were quantified by observing the foraging behavior of woodrats on diets containing increasing concentrations of creosote resin. Desert woodrats reduced meal size as resin concentration in the diet increased, resulting in an overall reduction in daily intake and regulation of resin intake. Moreover, desert woodrats were able to detect resin concentrations in the diet and regulate the intake of resin very rapidly. We suggest that the immediate and sustained ability to detect and regulate the intake of resin concentrations during each foraging bout provides a behavioral mechanism to regulate blood concentrations of resin and allows desert woodrats to make "wise" foraging decisions.
[Pubmed: 16163555]
| | 14. |
2005 Jun 01 |
Prevalence and intensity of blood and intestinal parasites in a field population of a Mediterranean lizard, Lacerta lepida.
Amo L, Fargallo JA, Martínez-Padilla J, Millán J, López P, Martín J
Parasitol. Res. 2005 Aug;96(6):413-7. Epub 2005 Jun 01.
Abstract
We describe the blood and intestinal parasites in the Ocellated lizard, Lacerta lepida, examining the factors that determine the prevalence and intensity of infection of haemogregarines, and the prevalence of coccidia and nematodes. In relation to haemogregarines, no juveniles were detected as being infected, whereas 71.7 % of adults were infected. The prevalence of infection was positively related to the size of the adults. There were no differences between seasons or sexes in the prevalence or intensity of infection in adults. There were no significant differences in the prevalence of infection by nematodes between ages or sexes, nor in relation to the size of adult lizards, but adult lizards excreting coccidian oocysts tend to be smaller. During the mating period, reproductive activities lead to a decrease in the body condition. However, neither the intensity of haemogregarine's infection nor the prevalence of intestinal parasites was related to the lizards' body condition.
[Pubmed: 15928907]
| | 15. |
2002 Dec |
Molecular systematics of the genus Neotoma.
Edwards CW, Bradley RD
Mol. Phylogenet. Evol. 2002 Dec;25(3):489-500.
Abstract
DNA sequences from the mitochondrial DNA cytochrome-b gene were used to infer the systematic relationships of 13 species of wood rats (genus Neotoma). Parsimony, likelihood, and neighbor-joining analyses produced similar topologies in most cases and produced six systematic conclusions. First, results of previous studies were supported in the recognition of N. floridana magister as distinct species (N. magister). Second, evidence was provided for the recognition of cryptic species within N. albigula (N. albigula and N. leucodon) and N. mexicana (N. mexicana, N. isthmica, and N. picta). Third, the subgenus Neotoma is composed of four species groups (floridana, lepida, mexicana, and micropus). Fourth, support was provided for placement of N. stephensi within the lepida species group. Fifth, support was provided for the recognition of Hodomys as a separate genus, sister to Xenomys. Sixth, support for the elevation of the subgenus Teonoma to generic status is discussed.
[Pubmed: 12450753]
| | 16. |
2009 Nov 10 |
Phylogenetic relationships in the genus Cyprinella (Actinopterygii: Cyprinidae) based on mitochondrial and nuclear gene sequences.
Schönhuth S, Mayden RL
Mol. Phylogenet. Evol. 2009 Nov 10; [Epub ahead of print]
Abstract
Members of the genus Cyprinella are abundant and broadly distributed cyprinids in central and eastern rivers of North America. Currently, 30 species are placed in this genus, including seven species restricted to Mexico and three barbeled species formerly placed in different genera (Hybopsis, Erimonax). Phylogenetic analyses were performed for all recognized species of Cyprinella plus species from 14 related genera using complete nucleotide sequences of one mitochondrial (cytochrome b) and one nuclear (Rag1) gene. Cyprinella revealed high levels of genetic divergence between species in both genes compared with species from other related genera examined. Analyses of mitochondrial sequences from 98 specimens of Cyprinella revealed the gene trees of some species as non-monophyletic (i.e., C. venusta, C. lepida, C. nivea, C. lutrensis, C. whipplei). Mitochondrial analyses recovered nine well-supported species groups within a main clade inclusive of most species of Cyprinella, although resolution regarding the monophyly of the genus or its relationships with other genera was poorly resolved, except for C. callistia and C. monacha, two species that are apparently not part of the genus. Analyses of nuclear gene sequences from selected distinctive mitochondrial clades also recovered these nine clades and resulted in shorter branches but greater resolution at more basal nodes. Nuclear data also rejected the inclusion of C. monacha in Cyprinella and indicated that Cyprinella is not monophyletic if Tampichthys and Codoma are recognized as valid genera. A major Clade A (formed by Cyprinella, Tampichthys, Codoma) is more closely related to Pimephales, Opsopoeodus, Hybognathus and some Notropis than to Luxilus and Lythrurus as previously hypothesized. Although mitochondrial data are highly informative phylogenetically, our research revealed fundamental conflicts among mitochondrial and nuclear data for several species of Cyprinella. Interestingly, nuclear trees recovered some species resolved as polyphyletic with mitochondrial variation as monophyletic. While we remain highly supportive of phylogenetic studies using mitochondrial genes and genomes, this study does highlight the utility of nuclear data by identifying issues of possible hybridization or retained ancestral polymorphisms and lineage sorting that can yield erroneous hypothesis in studies using only mit-DNA analyses, while shedding invaluable light on the phylogeny of this controversial group of shiners.
[Pubmed: 19903533]
| | 17. |
2009 May 07 |
Instrumental analysis of terminal-conjugated dienes for reexamination of the sex pheromone secreted by a nettle moth, Parasa lepida lepida.
Islam MD, Yamakawa R, Do ND, Numakura N, Suzuki T, Ando T
Biosci. Biotechnol. Biochem. 2009 May;73(5):1156-62. Epub 2009 May 07.
Abstract
Conjugated dienyl compounds make one of the main groups of lepidopteran sex pheromones, and GC has been frequently used to determine the configurations of the double bonds. However, the separation of two geometric isomers of a terminal-conjugated diene, such as 7,9-decadien-1-ol secreted by a nettle moth Parasa lepida lepida (Limacodidae), is assumed to be difficult. In order to clarify the chromatographic separation of the terminal dienes, 7,9-decadienyl and 9,11-dodecadienyl compounds (alcohols, acetates, and aldehydes) were analyzed by GC and HPLC. On a capillary GC column, the (E)-isomers flowed out slightly faster than the corresponding (Z)-isomers, but their peaks almost overlapped. On the other hand, HPLC equipped with an ODS column completely separated the two geometric isomers examined and the (Z)-isomers eluted from the column faster than the (E)-isomers without dependence on a functional group. In addition to undergoing direct HPLC analysis without derivatization, the dienyl alcohols were converted into 3,5-dinitrobenzoates and analyzed by LC-ESI-MS operated under the same reversed-phase condition. The two separated geometric isomers were sensitively monitored by negative ions at m/z 211, M, M+1, M+17, and M+31, which were characteristically derived from the benzoates. Based on these results, a pheromone extract of P. l. lepida was examined, and it was confirmed that the female moths exclusively produced the (Z)-isomer of the 7,9-diene. Furthermore, a GC-EAD analysis and a field evaluation with both geometrical isomers indicated that the mating communication of P. l. lepida is predominantly mediated with the (Z)-isomer.
[Pubmed: 19420704]
| | 18. |
2004 Jul |
Creosote bush (Larrea tridentata) resin increases water demands and reduces energy availability in desert woodrats (Neotoma lepida).
Mangione AM, Dearing MD, Karasov WH
J. Chem. Ecol. 2004 Jul;30(7):1409-29.
Abstract
Although many plant secondary compounds are known to have serious consequences for herbivores, the costs of processing them are generally unknown. Two potential costs of ingestion and detoxification of secondary compounds are elevation of the minimum drinking water requirement and excretion of energetically expensive metabolites (i.e., glucuronides) in the urine. To address these impacts, we studied the costs of ingestion of resin from creosote bush (Larrea tridentata) on desert woodrats (Neotoma lepida). The following hypotheses were tested: ingestion of creosote resin by woodrats (1) increases minimum water requirement and (2) reduces energy available by increasing fecal and urinary energy losses. We tested the first hypothesis, by measuring the minimum water requirement of woodrats fed a control diet with and without creosote resin. Drinking water was given in decreasing amounts until woodrats could no longer maintain constant body mass. In two separate experiments, the minimum drinking water requirement of woodrats fed resin was higher than that of controls by 18-30% (about 1-1.7 ml/d). We tested several potential mechanisms of increased water loss associated with the increase in water requirement. The rate of fecal water loss was higher in woodrats consuming resin. Neither urinary water nor evaporative water loss was affected by ingestion of resin. Hypothesis 2 was tested by measuring energy fluxes of woodrats consuming control vs. resin-treated diets. Woodrats on a resin diet had higher urinary energy losses and, thus, metabolized a lower proportion of the dietary energy than did woodrats on control diet. Fecal energy excretion was not affected by resin. The excretion of glucuronic acid represented almost half of the energy lost as a consequence of resin ingestion. The increased water requirement and energy losses of woodrats consuming a diet with resin could have notable ecological consequences.
[Pubmed: 15503528]
| | 19. |
2010 Apr 24 |
Multimodal sexual signals in male ocellated lizards Lacerta lepida: vitamin E in scent and green coloration may signal male quality in different sensory channels.
Martín J, López P
Naturwissenschaften. 2010 Jun;97(6):545-53. Epub 2010 Apr 24.
Abstract
The mechanisms that confer honesty to multiple sexual signals of vertebrates remain less known. We suggest that vitamin E in the scent (femoral secretions) and carotenoids in coloration of Lacerta lepida lizards might advertise quality because they are relevant in metabolism as major antioxidants and have a dietary origin. Results showed that there may be similar trade-offs between immunity and both chemical and visual signaling, as males with more vitamin E in secretions and those with more greenish, darker, and saturated carotenoid-dependent colorations had a higher immune response. This suggests that only high-quality males can divert from metabolism and allocate enough vitamin E to secretions and enough carotenoids to coloration. Therefore, information provided by visual and chemical signals is congruent. The use of multiple sensory channels may allow signaling a male quality under different circumstances or reinforce the reliability of the signal when both signals are perceived simultaneously. However, we also found that characteristics of carotenoid-dependent coloration mirror the amounts of vitamin E in secretions. This might support that carotenoids, which are not true antioxidants in the organism, would just reflect and "inform" on the actual contents of metabolic antioxidant vitamin E, which is part of the true system that prevent oxidation. We suggest that the metabolic roles of vitamins might be the actual basis of honesty of many sexual displays, and that carotenoid-based signals might be just the visible part of the whole system.
[Pubmed: 20419284]
| | 20. |
2010 Apr 6 |
First isolation and characterization of a novel lectin with potent antitumor activity from a Russula mushroom.
Zhang G, Sun J, Wang H, Ng TB
Phytomedicine. 2010 Apr 6; [Epub ahead of print]
Abstract
To date only a ribonuclease and a protein with anti-HIV-1 reverse transcriptase activity have been isolated from mushrooms of the genus Russula. In this study a novel lectin, with a molecular weight of 32kDa, and a unique N-terminal sequence different from other lectins, was isolated from the mushroom Russula lepida. It represents the first lectin isolated from Russula mushrooms. The purification scheme involved (NH(4))(2)SO(4) precipitation, ion exchange chromatography on diethylaminoethyl DEAE-cellulose and SP-Sepharose, and fast protein liquid chromatography-gel filtration on Superdex 75. The hemagglutinating activity of the lectin (RLL) was inhibited by inulin and O-nitrophenyl-beta-D-galacto-pyranoside. The lectin was stable at temperatures up to 70 degrees C (half of the activity was preserved at 80 degrees C), and in the presence of NaOH or HCl solutions up to a concentration of 12.5mM. Its hemagglutinating activity was reduced in the presence of Mn(2+), Co(2+), and Hg(2+) ions, and enhanced by Cu(2+) ions. It exhibited antiproliferative activity toward hepatoma Hep G2 cells and human breast cancer MCF-7 cells with an IC(50) of 1.6muM and 0.9muM, respectively. Daily intraperitoneal injections of RLL (5.0mg/kg body weight/day for 20 days) brought about 67.6% reduction in the weight of S-180 tumor. RLL was devoid of antifungal, ribonuclease, and HIV-1 reverse transcriptase inhibitory activities.
[Pubmed: 20378319]
| | 21. |
2010 Nov 22 |
Multiple approaches to detect outliers in a genome scan for selection in ocellated lizards (Lacerta lepida) along an environmental gradient.
Nunes VL, Beaumont MA, Butlin RK, Paulo OS
Mol. Ecol. 2011 Jan;20(2):193-205. Epub 2010 Nov 22.
Abstract
Identification of loci with adaptive importance is a key step to understand the speciation process in natural populations, because those loci are responsible for phenotypic variation that affects fitness in different environments. We conducted an AFLP genome scan in populations of ocellated lizards (Lacerta lepida) to search for candidate loci influenced by selection along an environmental gradient in the Iberian Peninsula. This gradient is strongly influenced by climatic variables, and two subspecies can be recognized at the opposite extremes: L. lepida iberica in the northwest and L. lepida nevadensis in the southeast. Both subspecies show substantial morphological differences that may be involved in their local adaptation to the climatic extremes. To investigate how the use of a particular outlier detection method can influence the results, a frequentist method, DFDIST, and a Bayesian method, BayeScan, were used to search for outliers influenced by selection. Additionally, the spatial analysis method was used to test for associations of AFLP marker band frequencies with 54 climatic variables by logistic regression. Results obtained with each method highlight differences in their sensitivity. DFDIST and BayeScan detected a similar proportion of outliers (3-4%), but only a few loci were simultaneously detected by both methods. Several loci detected as outliers were also associated with temperature, insolation or precipitation according to spatial analysis method. These results are in accordance with reported data in the literature about morphological and life-history variation of L. lepida subspecies along the environmental gradient.
[Pubmed: 21091562]
| | 22. |
2011 Jun 17 |
Phylogeography and demographic history of Lacerta lepida in the Iberian Peninsula: multiple refugia, range expansions and secondary contact zones.
Miraldo A, Hewitt GM, Paulo OS, Emerson BC
BMC Evol Biol. 2011 Jun 17;11(1):170. Epub 2011 Jun 17.
Abstract
ABSTRACT: BACKGROUND: The Iberian Peninsula is recognized as an important refugial area for species survival and diversification during the climatic cycles of the Quaternary. Recent phylogeographic studies have revealed Iberia as a complex of multiple refugia. However, most of these studies have focused either on species with narrow distributions within the region or species groups that, although widely distributed, generally have a genetic structure that relates to pre-Quaternary cladogenetic events. In this study we undertake a detailed phylogeographic analysis of the lizard species, Lacerta lepida, whose distribution encompasses the entire Iberian Peninsula. We attempt to identify refugial areas, recolonization routes, zones of secondary contact and date demographic events within this species. RESULTS: Results support the existence of 6 evolutionary lineages (phylogroups) with a strong association between genetic variation and geography, suggesting a history of allopatric divergence in different refugia. Diversification within phylogroups is concordant with the onset of the Pleistocene climatic oscillations. The southern regions of several phylogroups show a high incidence of ancestral alleles in contrast with high incidence of recently derived alleles in northern regions. All phylogroups show signs of recent demographic and spatial expansions. We have further identified several zones of secondary contact, with divergent mitochondrial haplotypes occurring in narrow zones of sympatry. CONCLUSIONS: The concordant patterns of spatial and demographic expansions detected within phylogroups, together with the high incidence of ancestral haplotypes in southern regions of several phylogroups, suggests a pattern of contraction of populations into southern refugia during adverse climatic conditions from which subsequent northern expansions occurred. This study supports the emergent pattern of multiple refugia within Iberia but adds to it by identifying a pattern of refugia coincident with the southern distribution limits of individual evolutionary lineages. These areas are important in terms of long-term species persistence and therefore important areas for conservation.
[Pubmed: 21682856]
| | 23. |
2011 Aug 4 |
Association of Mc1r variants with ecologically relevant phenotypes in the European ocellated lizard, Lacerta lepida.
Nunes VL, Miraldo A, Beaumont MA, Butlin RK, Paulo OS
J Evol Biol. 2011 Aug 4; [Epub ahead of print]
Abstract
A comprehensive knowledge on the genetic basis of coloration is crucial to understand how new colour phenotypes arise and how they contribute to the emergence of new species. Variation in melanocortin-1 receptor (Mc1r), a gene that has been reported as a target for repeated evolution in a wide range of vertebrate taxa, was assessed in European ocellated lizards (Lacerta lepida) to search for associations with melanin-based colour phenotypes. Lacerta lepida subspecies' distribution is associated with the three major bio-climatic regions in the Iberian Peninsula. A nonconserved and derived substitution (T162I) was associated with the L. l. nevadensis phenotype (prevalence of brown scales). Another substitution (S172C) was associated with the presence of black scales in both L. l. lepida and L. l. iberica, but no mutations were found to be associated with the higher proportion of black in L. l. iberica. Extensive genotyping of Mc1r along the contact zone between L. l. nevadensis and L. l. lepida revealed low gene flow (only two hybrids detected). The implications of these findings are discussed in the context of previous knowledge about the evolutionary history of ocellated lizards.
[Pubmed: 21812853]
| | 24. |
2011 May 04 |
Current and historical hybridization with differential introgression among three species of cyprinid fishes (genus Cyprinella).
Broughton RE, Vedala KC, Crowl TM, Ritterhouse LL
Genetica. 2011 May;139(5):699-707. Epub 2011 May 04.
Abstract
Hybridization is common among freshwater fishes, particular among the Cyprinidae. We used two mitochondrial genes and one nuclear gene to characterize hybridization among two species pairs of Cyprinella in southwestern North America. Genalogical patterns revealed that C. lutrensis and C. venusta are currently hybridizing in several localities producing apparent F(1), F(2) and backcross generations, yet there was no evidence for introgression outside of local hybrid zones. Alternatively, mitochondrial haplotypes from C. lutrensis appear to have introgressed into a C. lepida population in the Nueces River completely replacing the native C. lepida haplotype. There was no evidence of introgression of nuclear DNA and there does not appear to be ongoing hybridization. The population of C. lepida from the nearby Frio River exhibits no evidence of hybridization with C. lutrensis. Thus, contact between C. lutrensis and C. venusta results in the formation of localized hybrid swarms, while contact between C. lutrensis and C. lepida has resulted in complete mitochondrial introgression in the Nueces River or no apparent hybridization in the Frio River. The three different outcomes of contact between these species illustrate the variable nature of interspecific reproductive interactions and provide an excellent system in which to better understand the factors influencing hybridization among freshwater fishes.
[Pubmed: 21541803]
| | 25. |
2004 Jul |
[The roles of the NANA and LEPIDA genes in regulating the stem growth in Arabidopsis thaliana].
Lebedeva OV, Skliarova OA, Ezhova TA
Genetika. 2004 Jul;40(7):940-8.
Abstract
Genetic, physiological, and morphological studies of dwarf mutants of Arabidopsis thaliana (L.) Heynh. from the collection of the Department of Genetics and Breeding, Moscow State University, showed that the NA and LE genes are involved in regulating elongation of internode cells and sensitivity to various hormones. The na mutation suppressed stem growth only in the presence of the active LE gene. The absence of the LE activity (in the lele homozygote) restored stem growth of the na mutant to the level characteristic of the le-2 mutant, and a decrease in LE activity (in LEle heterozygote) almost completely suppressed the na phenotype. Phenotypic analysis of homozygous double mutants and heterozygotes obtained by crossing the na and le-2 mutants showed that the recessive le-2 allele has an epistatic effect on the semidominant na allele and that the genes possibly control consecutive steps of one biochemical pathway or one morphogenetic process. A hypothetical scheme was proposed for the interaction of the NA and LE gene products.
[Pubmed: 15458205]
| | 26. |
|
[A rare cause of superior vena cava syndrome].
Lepida A, Berghmans T, Sculier JP, Meert AP
Rev Med Brux.;32(5):481-3.
Abstract
A 85-year old patient with an history of low grade follicular lymphoma was admitted in the hospital with a superior vena cava (SVC) syndrome. The computed tomography scan of the thorax and the trans-esophageal echocardiography revealed a voluminous mass in the right atrium, extending to the origin of the SVC. A transvenous biopsy was done under echocardiographic control. The immunohistology showed a diffuse large B cell lymphoma. He received chemotherapy associating rituximab, doxorubicine, cyclophosphamide, vincristine and prednisone. The clinical response after the second cycle was remarkable with a near complete regression of the SVC syndrome. The tumor was no longer visible in imaging after four cycles of treatment.
[Pubmed: 22165527]
| | 27. |
2012 Jan 04 |
Numts help to reconstruct the demographic history of the ocellated lizard (Lacerta lepida) in a secondary contact zone.
Miraldo A, Hewitt GM, Dear PH, Paulo OS, Emerson BC
Mol. Ecol. 2012 Feb;21(4):1005-18. Epub 2012 Jan 04.
Abstract
In northwestern Iberia, two largely allopatric Lacerta lepida mitochondrial lineages occur, L5 occurring to the south of Douro River and L3 to the north, with a zone of putative secondary contact in the region of the Douro River valley. Cytochrome b sequence chromatograms with polymorphisms at nucleotide sites diagnostic for the two lineages were detected in individuals in the region of the Douro River and further north within the range of L3. We show that these polymorphisms are caused by the presence of four different numts (I-IV) co-occurring with the L3 genome, together with low levels of heteroplasmy. Two of the numts (I and II) are similar to the mitochondrial genome of L5 but are quite divergent from the mitochondrial genome of L3 where they occur. We show that these numts are derived from the mitochondrial genome of L5 and were incorporated in L3 through hybridization at the time of secondary contact between the lineages. The additional incidence of these numts to the north of the putative contact zone is consistent with an earlier postglacial northward range expansion of L5, preceding that of L3. We show that genetic exchange between the lineages responsible for the origin of these numts in L3 after secondary contact occurred prior to, or coincident with, the northward expansion of L3. This study shows that, in the context of phylogeographic analysis, numts can provide evidence for past demographic events and can be useful tools for the reconstruction of complex evolutionary histories.
[Pubmed: 22221514]
| | 28. |
2011 Aug 5 |
A catalogue of Lithuanian beetles (Insecta, Coleoptera)
Tamutis, Tamutė, Ferenca
Zookeys 2011 Aug 5;(121):1-494. published online before print
Abstract
This paper presents the first complete and updated list of all 3597 species of beetles (Insecta: Coleoptera) belonging to 92 familiesfound and published in Lithuania until 2011, with comments also provided on the main systematic and nomenclatural changes since the last monographic treatment in two volumes (Pileckis and Monsevičius 1995, 1997). The introductory section provides a general overview of the main features of the territory of Lithuania, the origins and formation of the beetle fauna and their conservation, the faunistic investigations in Lithuania to date revealing the most important stages of the faunistic research process with reference to the most prominent scientists, an overview of their work, and their contribution to Lithuanian coleopteran faunal research.
[Pubmed: 22461725]
| | 29. |
2011 Dec |
Incidental findings in focused assessment with sonography for trauma in hemodynamically stable blunt trauma patients: speaking about cost to benefit.
Sgourakis G, Lanitis S, Korontzi M, Kontovounisios C, Zacharioudakis C, Armoutidis V, Karaliotas C, Dedemadi G, Lepida N, Karaliotas C
J Trauma. 2011 Dec;71(6):E123-7.
Abstract
The purpose of this study was to identify which age-related groups of hemodynamically stable blunt trauma patients will present a positive cost-to-benefit ratio, in regard to the screening of incidental findings on Focused Assessment with Sonography for Trauma (FAST).
[Pubmed: 22182913]
| | 30. |
2007 Oct |
Secondary metabolites from higher fungi in China and their biological activity.
Liu JK
Drug Discov Ther. 2007 Oct;1(2):94-103.
Abstract
As a part of our search for naturally occurring bioactive metabolites from higher fungi, we investigated the chemical constituents of basidiomycetes and ascomycetes fungi (Albatrellus confluens, Albatrellus dispansus, Boletus edulis, Boletopsis grisea, Bondarzewia berkeleyi, Cortinarius tenuipes, Cortinarius vibratilis, Daldinia concentrica, Engleromyces goetzii, Hydnum repandum, Hebeloma versipelle, Hygrophorus eburnesus, Lactarius deliciosus, Lactarius hatsudake, Lactarius hirtipes, Lactarius mitissimus, Lactarius rufus, Paxillus panuoides, Pulveroboletus ravenelii, Russula cyanoxantha, Russula foetens, Russula lepida, Russula nigricans, Sarcodon laevigatum, Sarcodon scabrosus, Shiraia bambusicola, Thelephora aurantiotincta, Thelephora ganbajun, Tricholomopsis rutilans, Tylopilus virens, Tuber indicum, Xylaria euglossa, etc.), and isolated a number of novel terpenoids, phenolics, and nitrogen-containing compounds. The isolation, structural elucidation, and biologically activity of the new compounds are discussed.
[Pubmed: 22504394]
| | 31. |
2012 Jun 20 |
Experience matters: prior exposure to plant toxins enhances diversity of gut microbes in herbivores.
Kohl KD, Dearing MD, van Dam N
Ecol. Lett. 2012 Sep;15(9):1008-15. Epub 2012 Jun 20.
Abstract
For decades, ecologists have hypothesised that exposure to plant secondary compounds (PSCs) modifies herbivore-associated microbial community composition. This notion has not been critically evaluated in wild mammalian herbivores on evolutionary timescales. We investigated responses of the microbial communities of two woodrat species (Neotoma bryanti and N. lepida). For each species, we compared experienced populations that independently converged to feed on the same toxic plant (creosote bush, Larrea tridentata) to naïve populations with no exposure to creosote toxins. The addition of dietary PSCs significantly altered gut microbial community structure, and the response was dependent on previous experience. Microbial diversity and relative abundances of several dominant phyla increased in experienced woodrats in response to PSCs; however, opposite effects were observed in naïve woodrats. These differential responses were convergent in experienced populations of both species. We hypothesise that adaptation of the foregut microbiota to creosote PSCs in experienced woodrats drives this differential response.
[Pubmed: 22715970]
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