Factors related to the distribution and prevalence of the fungal pathogen Batrachochytrium dendrobatidis in Rana cascadae and other amphibians in the Klamath Mountains     

Jonah Piovia-Scott  Karen L. Pope  Sharon P. Lawler  Esther M. Cole  Janet E. Foley 《Biological conservation》2011,144(12):2913-2921

The fungal pathogen Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis, has been associated with declines and extinctions of montane amphibians worldwide. To gain insight into factors affecting its distribution and prevalence we focus on the amphibian community of the Klamath Mountains in northwest California. The Cascades frog (Rana cascadae), one of the most common amphibians in these mountains, experienced increased mortality as a result of Bd exposure in laboratory trials and has experienced recent, dramatic declines in other parts of California. We surveyed 112 sites in the Klamaths, all of which supported R. cascadae between 1999 and 2002, for amphibians and Bd to (1) determine the distribution of Bd, (2) evaluate changes in the distribution of R. cascadae, and (3) assess associations between potential biotic and abiotic drivers and Bd infection. Bd was widely distributed in the Klamath Mountains – we detected the pathogen at 64% of sites. R. cascadae was found at 79% of sites, and was often infected with Bd. These results suggest that Bd has not caused dramatic declines in R. cascadae in the Klamaths in recent years. Subadult R. cascadae had a higher Bd prevalence than other R. cascadae life stages (subadults: 36%, adults: 25%, metamorphs: 4%, larvae: 1%), and while the probability of infection decreased over the season for adults, it did not for subadults, suggesting that subadults may be more vulnerable to chytridiomycosis than other R. cascadae life stages. Bd prevalence in R. cascadae was highest early in the season at high-elevation sites, which may indicate that populations inhabiting high elevation sites may have a greater risk of being affected by chytridiomycosis. Three other common amphibian species also tested positive for Bd: Pacific chorus frog (Pseudacris regilla), western toad (Anaxyrus boreas), and rough-skinned newt (Taricha granulosa).  相似文献   

Influence of agricultural soils on the growth and reproduction of the bio-indicator Folsomia candida     

Karen Lindsey Nelson  Gilles Boiteau  Rick Daniel Peters 《Pedobiologia》2011,54(2):79-86

Soil organisms have been recommended as bio-indicators of soil quality due to their sensitivity to anthropogenic influences and their high degree of site-specificity. The objectives of this study were to determine if the relationship between the soil Collembola, Folsomia candida, and forest soil could be extended to other soils and, if not, to determine the relationship between its life parameters and soils from the different phases of an agricultural rotation sequence. A comparison of growth, reproduction and survival of 1 day old neonates and 10 day old juveniles subjected to a series of different soils (composted manure, pasture soil, forest soil, sand alone, and sand supplemented with yeast) established that the association between F. candida and forest soil quality cannot be automatically transferred to soils from other ecosystems. The test also showed that neonate (1 d) individuals were more sensitive to the different soil treatments than 10 d old juveniles and should be used in future tests. On this basis, neonate F. candida individuals were used to determine if the species could be employed to characterize the agricultural soils from the different phases of an organic or conventional rotation sequence. Results demonstrated that changes in body growth and reproduction constituted suitable criteria to characterize the soil quality of these different phases. The research required to develop these results as a standard bio-indicator test of agricultural soil quality is discussed.  相似文献   

Long-term plant growth legacies overwhelm short-term plant growth effects on soil microbial community structure     

Andrew Kulmatiski  Karen H. Beard 《Soil biology & biochemistry》2011,43(4):823-830

Plant-soil feedbacks are gaining attention for their ability to determine plant community development. Plant-soil feedback models and research assume that plant-soil interactions occur within days to weeks, yet, little is known about how quickly and to what extent plants change soil community composition. We grew a dominant native plant (Pseudoroegneria spicata) and a dominant non-native plant (Centaurea diffusa) separately in both native- and non-native-cultivated field soils to test if these species could overcome soil legacies and create new soil communities in the short-term. Soil community composition before and after plant growth was assessed in bulk and rhizosphere soils using phospholipid fatty acid analyses. Nematode abundance and mycorrhizal colonization were also measured following plant growth. Field-collected, native-cultivated soils showed greater bacterial, Gram (−), fungal, and arbuscular mycorrhizal PLFA abundance and greater PLFA diversity than field-collected, non-native-cultivated soils. Both plant species grew larger in native- than non-native-cultivated soils, but neither plant affected microbial composition in the bulk or rhizosphere soils after two months. Plants also failed to change nematode abundance or mycorrhizal colonization. Plants, therefore, appear able to create microbial legacies that affect subsequent plant growth, but contrary to common assumptions, the species in this study are likely to require years to create these legacies. Our results are consistent with other studies that demonstrate long-term legacies in soil microbial communities and suggest that the development of plant-soil feedbacks should be viewed in this longer-term context.  相似文献   

Primary lacrimal gland adenocarcinoma of the third eyelid in a horse     

Mathes RL  Paige Carmichael K  Peroni J  Anthony Moore P 《Veterinary ophthalmology》2011,14(1):48-54

A 5-year-old Draft Horse gelding presented for evaluation of a large, fleshy, ulcerated third eyelid mass OD of 3 weeks duration. Complete ophthalmic examination, ocular ultrasound and skull radiographs revealed a large soft-tissue mass involving the entire third eyelid OD and extending into the ventral right orbit to the level of the globe equator. No other abnormalities were noted on physical or ophthalmic examination. Surgical removal via exenteration was performed 3 months after initial presentation. A lacrimal adenocarcinoma of the third eyelid was diagnosed based on histopathology. Concurrent asymptomatic intra-ductal and intra-acinar Demodex caballi parasites were found in the eyelid sebaceous glands, likely as an incidental finding. No tumor recurrence or metastasis has occurred 12 months after excision. To the author's knowledge, this case is the first reported primary lacrimal adenocarcinoma in a horse. Complete surgical excision was curative.  相似文献   

Mojave toxin‐type ascending flaccid paralysis after an envenomation by a Southern Pacific Rattlesnake in a dog     

Sarah R. Hoggan DVM  Amy Carr DVM  DACVECC  Karen A. Sausman MS 《Journal of Veterinary Emergency and Critical Care》2011,21(5):558-564

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Bilateral hydronephrosis secondary to endometriosis managed by endoscopic ureteral stent placement in a captive Guinea baboon (Papio papio)     

Dallwig RK  Langan JN  Hatch DA  Terio KA  Demitros C 《Journal of zoo and wildlife medicine》2011,42(4):747-750

Spontaneous endometriosis is an estrogen-dependent, progressive and painful disease that affects a variety of nonhuman primates, including several species of baboons (Papio sp.). This case documents multimodal management of severe endometriosis in a captive female baboon within a zoological institution. An 18-yr-old, intact female Guinea baboon (Papio papio) was found to have an enlarged uterus. Fifteen months post ovariohysterctomy, scarring associated with endometrial tissue resulted in ureteral strictures, bilateral hydronephrosis, and azotemia. Cystoscopic placement of bilateral ureteral stents with fluoroscopy was performed and resulted in short-term clinical improvement. The animal's condition declined and euthanasia was elected 4 mo after ureteral stent placement. Severe endometriosis with secondary inflammation resulting in bilateral hydroureter and hydronephrosis, as well as concurrent cystitis, ureteritis, and pyelonephritis were confirmed at necropsy. Despite possible complications, ureteral stents can be considered a useful therapeutic option in patients with ureteral disease.  相似文献   

Amphibian population declines in montane southern Mexico: resurveys of historical localities     

Karen R. Lips  Joseph R. Mendelson III  Luis Canseco-Márquez 《Biological conservation》2004,119(4):555-564

Declines of amphibian populations have been well documented in the US, Canada, and Central America, but little is known regarding the status of amphibian populations in Mexico. In 2000, we surveyed 43 transects from 3 upland regions in Guerrero and Oaxaca, Mexico. We found 161 adult amphibians belonging to 39 species, representing only 19-48% of the anuran fauna known from these regions. We found one dead (Eleutherodactylus saltator) and one dying frog (Ptychohyla erythromma) from two different streams near Chilpancingo, Guerrero. Both frogs were infected with Batrachochytridium dendrobatidis, a pathogenic fungus involved in other declines of amphibian populations. We collected 368 tadpoles; 60 (19%) tadpoles from 9 different streams among the three regions were missing mouthparts, which is indicative of infection by chytrid fungus. We report additional data from the state of Chiapas, Mexico, that document declines, disease, and apparent extirpations from that region as well. Overall, we report 31 populations (representing 24 species) that appear to have been extirpated, including populations of as many as 11 endemic species that have been missing for 16-40 years and may be extinct.  相似文献   

New prenylated benzoic acid and other constituents from almond hulls (Prunus amygdalus Batsch).   总被引：2，自引：0，他引：2  

Shengmin Sang  Karen Lapsley  Robert T Rosen  Chi-Tang Ho 《Journal of agricultural and food chemistry》2002,50(3):607-609

One new prenylated benzoic acid derivative, 3-prenyl-4-O-beta-D-glucopyranosyloxy-4-hydroxylbenzoic acid, and three known constituents, catechin, protocatechuic acid, and ursolic acid, have been isolated from the hulls of almond (Prunus amygdalus). Complete assignments of the proton and carbon chemical shifts for the new prenylated benzoic acid derivative were accomplished on the basis of high-resolution 1D and 2D nuclear magnetic resonance data. All of these compounds except ursolic acid are being reported from almond hulls (P. amygdalus) for the first time.  相似文献   

Does shelterwood harvesting have less impact on forest floor nutrient availability and microbial properties than clearcutting?     

Robert L. Bradley  Brian D. Titus  Karen Hogg 《Biology and Fertility of Soils》2001,34(3):162-169

Chemical and microbial properties of the forest floor were measured in 4-year-old shelterwood treatment plots in the montane coastal western hemlock biogeoclimatic zone of British Columbia, Canada, and compared to those in adjacent old-growth and 4-year-old clearcut plots. Forest floor pH, exchangeable Mg, total C and total N concentrations were similar in all three treatments. Bray-extractable P was significantly lower in humus from shelterwood plots, exchangeable Ca was significantly lower in humus from clearcut plots, and exchangeable K was significantly higher in humus from old-growth plots. Indices of available C (basal respiration rate, microbial biomass and metabolic quotient) were significantly higher in old-growth plots than in the two harvested treatment plots. The relative increase in maximum microbial metabolic rate due to the addition of organic nutrients was significantly greater in clearcut plots. Principal component analysis (PCA) ordination of humus samples based on C source utilization patterns of microbial communities (i.e., Biolog assay) showed distinctive clustering by treatment, although indices of substrate richness, evenness and diversity were the same in all three treatments. The relative utilization rates of substrates with the highest factor loadings on PCA axes 1 and 2 were dissimilar in each treatment. We conclude that forest floors can develop under shelterwood harvested stands to exhibit chemical and microbial properties atypical of either clearcut or old-growth plots.  相似文献   

Sphingolipid and other constituents from almond nuts (Prunus amygdalus Batsch)   总被引：3，自引：0，他引：3  

Sang S  Kikuzaki H  Lapsley K  Rosen RT  Nakatani N  Ho CT 《Journal of agricultural and food chemistry》2002,50(16):4709-4712

One sphingolipid, 1-O-beta-D-glucopyranosyl-(2S,3R,4E,8Z)-2-[(2R)-2-hydroxyhexadecanoylamino]-4,8-octadecadiene-1,3-diol, and four other constituents, beta-sitosterol, daucosterol, uridine, and adenosine, have been isolated from the nuts of almond (Prunus amygdalus). Complete assignments of the proton and carbon chemical shifts for the sphingolipid were accomplished on the basis of high-resolution 1D and 2D NMR data. All of these compounds are being reported from almond nuts (P. amygdalus)for the first time.  相似文献