Publications

TitleAbstractYear
Filter
PMID
Filter
effects of sodium chloride concentration on solubility and electrophoretic characteristics of protein from the eye lens nucleus in a yellowfin tuna (thunnus albacares) and in a desert wood rat (neotoma lepida). 19685758384
factors affecting the seasonal abundance of ground squirrel and wood rat fleas (siphonaptera) in san diego county, california.abiotic and biotic factors affecting the seasonal abundance of 3 species of sylvatic fleas on their hosts were examined at 7 sites in san diego county, california. indices for oropsylla (diamanus) montana (baker) were usually highest on spermophilus beecheyi nudipes (huey) when < 18.4 degrees c (october-december), whereas those for hoplopsyllus anomalus (baker) were highest when > 18.4 degrees c (july-september). o. montana was affected most by ambient temperature (inversely for the coastal site ...19968840686
dermacentor hunteri (acari: ixodidae): seasonal variation in questing adults and on-host juvenile stages, and host associations and feeding behavior of larvae and nymphs.dermacentor hunteri bishopp is the only completely desert adapted tick in the nearctic realm, and chiefly parasitizes desert bighorn sheep (ovis canadensis shaw) as an adult. the remainder of its life history has been unknown. we conducted field investigations in the sonoran desert of the temporal and spatial variation of adult host-seeking ticks and of the host associations of juvenile ticks. additionally, the feeding success of juvenile ticks was assessed in the laboratory. adult ticks were fo ...19989835699
arenavirus antibody in rodents indigenous to coastal southern california.the purpose of this study was to extend our knowledge on the geographic and natural rodent host ranges of new world arenaviruses in california. sera from 1,094 sigmodontine and 112 murine rodents were tested for antibody against whitewater arroyo and amapari viruses. antibody was found in 55 (4.6%) of the 1,206 rodents: 4 from northwestern san diego county, 3 from los angeles county, and 48 from orange county. the antibody-positive rodents included 8 (7.8%) of 103 neotoma fuscipes, 1 (0.6%) of 1 ...200011289675
comparison of detoxification enzyme mrnas in woodrats (neotoma lepida) and laboratory rats.to understand how mammalian herbivores process plant secondary compounds, we examined differences in expression of biotransformation enzyme mrnas among populations of wild woodrats (neotoma lepida) and laboratory rats. we compared expression of mrnas for 10 biotransforming enzymes in five families (cyp, meh, qor, gst, and ugt) by using northern blot analysis. we found significant differences in eight of 10 mrnas tested. we suggest that the differences in mrna expression among populations of wood ...200111446304
a preliminary report on a brucella isolated from the desert wood rat, neotoma lepida thomas. 195713428626
detection and characterization of borrelia bissettii in rodents from the central california coast.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, per ...200415311469
mammal and flea relationships in the great basin desert: from h. j. egoscue's collections.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 spec ...200616729681
epizootiology of tacaribe serocomplex viruses (arenaviridae) associated with neotomine rodents (cricetidae, neotominae) in southern california.the objective of this study was to advance our knowledge of the epizootiology of bear canyon virus and other tacaribe serocomplex viruses (arenaviridae) associated with wild rodents in california. antibody (immunoglobulin g [igg]) to a tacaribe serocomplex virus was found in 145 (3.6%) of 3977 neotomine rodents (cricetidae: neotominae) captured in six counties in southern california. the majority (122 or 84.1%) of the 145 antibody-positive rodents were big-eared woodrats (neotoma macrotis) or ca ...201525700047
detoxification rates of wild herbivorous woodrats (neotoma).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 w ...200616962347
a new species of brucella isolated from the desert wood rat, neotoma lepida thomas. 195713470254
effect of litter size on postnatal growth and survival in the desert woodrat. 19734706251
intestinal absorption in heat and cold acclimated desert woodrats. 1979450914
the development of thermoregulation in two species of woodrats, neotoma lepida and neotoma albigula. 19764272
ambient temperature influences tolerance to plant secondary compounds in a mammalian herbivore.growing evidence suggests that plant secondary compounds (pscs) ingested by mammals become more toxic at elevated ambient temperatures, a phenomenon known as temperature-dependent toxicity. we investigated temperature-dependent toxicity in the desert woodrat (neotoma lepida), a herbivorous rodent that naturally encounters pscs in creosote bush (larrea tridentata), which is a major component of its diet. first, we determined the maximum dose of creosote resin ingested by woodrats at warm (28-29°c ...201626763703
warmer ambient temperatures depress liver function in a mammalian herbivore.diet selection in mammalian herbivores is thought to be mainly influenced by intrinsic factors such as nutrients and plant secondary compounds, yet extrinsic factors like ambient temperature may also play a role. in particular, warmer ambient temperatures could enhance the toxicity of plant defence compounds through decreased liver metabolism of herbivores. temperature-dependent toxicity has been documented in pharmacology and agriculture science but not in wild mammalian herbivores. here, we in ...201324046878
structure-function analysis of mammalian cyp2b enzymes using 7-substituted coumarin derivatives as probes: utility of crystal structures and molecular modeling in understanding xenobiotic metabolism.crystal structures of cyp2b35 and cyp2b37 from the desert woodrat were solved in complex with 4-(4-chlorophenyl)imidazole (4-cpi). the closed conformation of cyp2b35 contained two molecules of 4-cpi within the active site, whereas the cyp2b37 structure demonstrated an open conformation with three 4-cpi molecules, one within the active site and the other two in the substrate access channel. to probe structure-function relationships of cyp2b35, cyp2b37, and the related cyp2b36, we tested the o-dea ...201626826176
the draft genome sequence and annotation of the desert woodrat neotoma lepida.we present the de novo draft genome sequence for a vertebrate mammalian herbivore, the desert woodrat (neotoma lepida). this species is of ecological and evolutionary interest with respect to ingestion, microbial detoxification and hepatic metabolism of toxic plant secondary compounds from the highly toxic creosote bush (larrea tridentata) and the juniper shrub (juniperus monosperma). the draft genome sequence and annotation have been deposited at genbank under the accession lzpo01000000.201627408812
ambient temperature-mediated changes in hepatic gene expression of a mammalian herbivore (neotoma lepida).herbivores regularly ingest natural toxins produced by plants as a defence against herbivory. recent work suggests that compound toxicity is exacerbated at higher ambient temperatures. this phenomenon, known as temperature-dependent toxicity (tdt), is the likely result of decreased liver function at warmer temperatures; however, the underlying cause of tdt remains speculative. in the present study, we compared the effects of temperature and dietary plant toxins on differential gene expression in ...201728653444
cytochrome p450 2b diversity and dietary novelty in the herbivorous, desert woodrat (neotoma lepida).detoxification enzymes play a key role in plant-herbivore interactions, contributing to the on-going evolution of ecosystem functional diversity. mammalian detoxification systems have been well studied by the medical and pharmacological industries to understand human drug metabolism; however, little is known of the mechanisms employed by wild herbivores to metabolize toxic plant secondary compounds. using a wild rodent herbivore, the desert woodrat (neotoma lepida), we investigated genomic struc ...201222927909
an oak (quercus agrifolia) specialist (neotoma macrotis) and a sympatric generalist (neotoma lepida) show similar intakes and digestibilities of oak.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 determin ...201718544017
seasonal changes in the water metabolism of woodrats.dusky-footed woodrats (neotoma fuscipes) and desert woodrats (n. lepida) experience pronounced seasonal variations in the aridity of their habitats. the effects of seasonal aridity upon the water conserving abilities of these species were assessed through measurements of water conserving abilities and kidney structure of animals captured in summer and winter, and through measurements of animals' abilities to acclimate to differing water availabilities in the laboratory.urine concentrating abilit ...197928308890
adaptation to oak and other fibrous, phenolic-rich foliage by a small mammal, neotoma fuscipes.neotoma fuscipes, a small mammalian herbivore with apparently generalized food habits, was laboratory tested to determine its degree of dietary specialization. woodrats from both oak woodland and coastal sage communities preferred quercus agrifolia leaves (containing 40% phenolics and about 16% condensed tannin) over foliage from other dominant species. approximately one-third of the oak phenolics and less than 10% of the oak condensed tannin remained in the feces. their performance on pure oak ...198328310547
experimental evidence for asymmetric mate preference and aggression: behavioral interactions in a woodrat (neotoma) hybrid zone.female mate preferences may be under strong selection in zones of contact between closely related species because of greater variation in available mates and the potential costs of hybridization. we studied female mate preferences experimentally in a zone of secondary contact between desert and bryant's woodrat (neotoma lepida and n. bryanti) in the southern foothills of the sierra nevada of california. we tested female preference for conspecific versus heterospecific males in paired choice tria ...201324093823
functional characterization of cytochromes p450 2b from the desert woodrat neotoma lepida.mammalian detoxification processes have been the focus of intense research, but little is known about how wild herbivores process plant secondary compounds, many of which have medicinal value or are drugs. cdna sequences that code for three enzymes of the cytochrome p450 (cyp) 2b subfamily, here termed 2b35, 2b36, and 2b37 have been recently identified from a wild rodent, the desert woodrat (malenke et al., 2012). two variant clones of each enzyme were engineered to increase protein solubility a ...201424361551
"pharm-ecology" of diet shifting: biotransformation of plant secondary compounds in creosote (larrea tridentata) by a woodrat herbivore, neotoma lepida.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 o ...200818752424
creosote bush (larrea tridentata) resin increases water demands and reduces energy availability in desert woodrats (neotoma lepida).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 (neotom ...200415503528
detoxification in relation to toxin tolerance in desert woodrats eating creosote bush.we studied the relationship between the use of three detoxification pathways and urine ph and the tolerance of desert woodrats from two populations to a mixture of naturally occurring plant secondary metabolites (mostly phenolics) in resin from creosote bush (larrea tridentata). the two populations of desert woodrats came from the mojave desert (mojave woodrats), where woodrats consume creosote bush, and from the great basin desert (great basin woodrats), where the plant species is absent. we fe ...200111789959
how do food passage rate and assimilation differ between herbivorous lizards and nonruminant mammals?what digestive adaptations permit herbivorous nonruminant mammals to sustain much higher metabolic rates than herbivorous lizards, despite gross similarity in digestive anatomy and physiology? we approached this question by comparing four herbivorous species eating the same diet of alfalfa pellets: two lizards (chuckwalla and desert iugana) and two mammals (desert woodrat and laboratory mouse). the mammals had longer small and large intestines, greater intestinal surface area, much higher (by an ...19863734193
an in vivo assay for elucidating the importance of cytochromes p450 for the ability of a wild mammalian herbivore (neotoma lepida) to consume toxic plants.an in vivo assay using the cytochrome p450 (p450) suicide inhibitor 1-aminobenzotriazole (abt) and 24-h food intake was developed to determine the relative importance of p450s in two populations of neotoma lepida with respect to biotransformation of plant secondary compounds in the animals' natural diets. the efficacy of abt as a p450 inhibitor was first validated using hypnotic-state assays with and without pretreatment with abt. pretreatment with 100 mg/kg abt by gavage increased hexobarbital ...201723995490
hepatic gene expression in herbivores on diets with natural and novel plant secondary compounds.herbivores are predicted to evolve appropriate mechanisms to process the plant secondary compounds (pscs) in their diet, and these mechanisms are likely specific to particular suites of pscs. changes in diet composition over evolutionary time should select for appropriate alterations in metabolism of the more recent dietary components. we investigated differences in gene expression profiles in the liver with respect to prior ecological and evolutionary experience with pscs in the desert woodrat, ...201323859940
transcriptome sequencing and microarray development for the woodrat (neotoma spp.): custom genetic tools for exploring herbivore ecology.massively parallel sequencing has enabled the creation of novel, in-depth genetic tools for nonmodel, ecologically important organisms. we present the de novo transcriptome sequencing, analysis and microarray development for a vertebrate herbivore, the woodrat (neotoma spp.). this genus is of ecological and evolutionary interest, especially with respect to ingestion and hepatic metabolism of potentially toxic plant secondary compounds. we generated a liver transcriptome of the desert woodrat (ne ...201323496907
assessment of mercury concentrations in small mammals collected near las vegas, nevada, usa.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 highe ...200617091502
expression of biotransformation genes in woodrat (neotoma) herbivores on novel and ancestral diets: identification of candidate genes responsible for dietary shifts.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 ...200919389177
plant secondary metabolites alter the feeding patterns of a mammalian herbivore (neotoma lepida).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 ...200516163555
using the specialization framework to determine degree of dietary specialization in a herbivorous woodrat.to be considered a dietary specialist, mammalian herbivores must consume large quantities of a plant species considered "difficult" with respect to nutrient or toxin content, and possess specialized adaptations to deal with plant defensive compounds or low nutritional content. populations of neotoma lepida in the great basin consume juniperus osteosperma, a plant heavily defended by terpenes, but a detailed dietary analysis of this population is lacking. therefore, we investigated the extent of ...201526631406
evidence for functional convergence in genes upregulated by herbivores ingesting plant secondary compounds.nearly 40 years ago, freeland and janzen predicted that liver biotransformation enzymes dictated diet selection by herbivores. despite decades of research on model species and humans, little is known about the biotransformation mechanisms used by mammalian herbivores to metabolize plant secondary compounds (pscs). we investigated the independent evolution of psc biotransformation mechanisms by capitalizing on a dramatic diet change event-the dietary inclusion of creosote bush (larrea tridentata) ...201425123454
gut microbes of mammalian herbivores facilitate intake of plant toxins.the foraging ecology of mammalian herbivores is strongly shaped by plant secondary compounds (pscs) that defend plants against herbivory. conventional wisdom holds that gut microbes facilitate the ingestion of toxic plants; however, this notion lacks empirical evidence. we investigated the gut microbiota of desert woodrats (neotoma lepida), some populations of which specialise on highly toxic creosote bush (larrea tridentata). here, we demonstrate that gut microbes are crucial in allowing herbiv ...201425040855
new host and locality records of coccidia (apicomplexa: eimeriidae) from rodents in the southwestern and western united states.one hundred forty-seven murid and heteromyid rodents were collected from various sites in the southwestern and western united states (arizona, colorado, new mexico, texas, and utah) and baja california norte, mexico, and their feces were examined for coccidial parasites. of these, 53 (36%) were infected with at least 1 coccidian; 45 of 53 (85%) of the infected rodents harbored only 1 species of coccidian. infected rodents included: 10 of 22 (45%) neotoma albigula, 3 of 11 (27%) neotoma floridana ...19911779282
detection of coccidioidal antibodies in serum of a small rodent community in baja california, mexico.coccidioidomycosis (valley fever) represents a serious threat to inhabitants of endemic areas of north america. despite successful clinical isolations of the fungal etiological agent, coccidioides spp., the screening of environmental samples has had low effectiveness, mainly because of the poor characterization of coccidioides ecological niche. we explored valle de las palmas, baja california, mexico, a highly endemic area near the u.s.-mexico border, where we previously detected coccidioides vi ...201424607357
wild-caught rodents retain a majority of their natural gut microbiota upon entrance into captivity.experiments conducted on captive animals allow scientists to control many variables; however, these settings are highly unnatural. previous research has documented a large difference in microbial communities between wild animals and captive-bred individuals. however, wild-caught animals brought into captivity might retain their natural microbiota and thus provide a better study system in which to investigate the ecology of the gut microbiome. we collected individuals of the desert woodrat (neoto ...201424596293
rational re-engineering of the oxidation of 7-alkoxycoumarin derivatives by cytochromes p450 2b from the desert woodrat neotoma lepida.based on recent functional and structural characterization of cytochromes p450 2b from the desert woodrat (neotoma lepida), the 7-alkoxycoumarin and 7-alkoxy-4-(trifluoromethyl)coumarin o-dealkylation profiles of cyp2b35 and 2b37 were re-engineered. point mutants interchanging residues at seven positions in the enzyme active sites were created and purified from an e. coli expression system. cyp2b37 i363a showed significantly reduced dealkylation of short chain 7-substituted coumarins and increas ...201728375626
larvae of the woodrat fleas anomiopsyllus amphibolus and atyphlocerus echis echis (siphonaptera: hystrichopsyllidae).the external morphology of anomiopsyllus amphibolus wagner, 1936 and atyphloceras echis echis jordan and rothschild, 1915 larvae (siphonaptera: hystrichopsyllidae) from woodrat (neotoma lepida) nests is described. among known flea larvae, the genus anomiopsyllus (anomiopsyllinae, anomiopsyllini) is as distinctive in larval form as are the adults. among other distinctive features, only anomiopsyllus are known to have only two ventrolateral setae. atyphloceras (hystrichopsyllinae, hystrichopsyllin ...19902201770
seasonal variation in na+-k+-atpase in tissues of field acclimatized woodrats, neotoma lepida.woodrats, neotoma lepida, were captured in the field over a 12 month period. the masses of the liver, kidney and intrascapular brown adipose tissue (ibat) were lowest during the latter part of the summer as was the specific activity of na+-k+-atpase in the liver and kidney. with cooling temperatures in the fall, liver mass and the na+-k+-atpase activity of both liver and kidney increased significantly. during the coldest months, december and january, the mass of ibat increased above the low summ ...19836138180
hormonal and sensory control of scent-marking in the desert woodrat (neotoma lepida lepida).in experiment 1, the marking behavior of adult male and female woodrats was tested in a neutral environment. males showed higher levels of ventral rubbing than females, whereas the reverse was true for the body-rolling response. in experiment 2, the influence of testosterone propionate and estradiol-17 on scent-marking in female and male gonadectomized experimental animals was investigated. animals were given a series of marking tests prior to an during social encounters with conspecifics. ventr ...19806993505
weight maintenance of the desert woodrat (neotoma lepida) on some natural foods. 19715545555
inoculation of tannin-degrading bacteria into novel hosts increases performance on tannin-rich diets.it has been hypothesized that herbivores host tannin-degrading bacteria (tdb) to overcome the toxic challenges posed by plant tannins. while tdb have been isolated from the guts of numerous mammals, their functional significance to their hosts has never been explicitly tested. we introduced tdb into lab rats, which do not host tdb, and measured host performance on tannin-rich diets. we first isolated three species of tdb, escherichia coli, bacillus subtilis and enterococcus faecalis, from the gu ...201625753857
the evolutionary dynamics of the desert woodrat, neotoma lepida. 197028562990
protein differences in the lens nucleus from the desert woodrat (neotoma lepida). 19751153581
the taxonomic properties of brucellae isolated from neotoma lepida thomas (brucella neotomae stoenner). 19674971180
[catenotaenia neotomae sp. n. (cestoda: dilepidae), a parasite of neotoma lepida (rodentia: cricetidae) in nevada, u.s.a]. 20066362681
intracellular invasion and survival of brucella neotomae, another possible zoonotic brucella species.in 1967, brucella neotomae was first isolated from neotoma lepida, the dessert wood rat, in utah. with little infection data since its discovery, the zoonotic potential of this brucella species is largely unknown. recent reports of isolation from human cerebrospinal fluid, along with current literature suggest that b. neotomae has the ability to infect various hosts and cell types. in this report we extend the knowledge of b. neotomae atcc 23459's intracellular invasion and survival abilities to ...201930943213
Displaying items 1 - 52 of 52