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101.
Cryptococcus species are environmental yeasts, with a worldwide distribution and remarkable environmental adaptation. Although many species do not cause disease, C. neoformans and C. gattii are causative agents of cryptococcosis, a life threatening infection and a significant public health problem worldwide. Infection especially affects immunocompromised animals and humans. In wildlife, cryptococcosis appears to be more prevalent in captive populations. The objective of this study was to assess whether apparently healthy quokkas (Setonix brachyurus) harbor Cryptococcus spp. Using cultural and molecular methods, we studied yeasts isolated from nasal swabs collected from 130 free-ranging quokkas on Rottnest Island (RI, n = 97) and the mainland (n = 33) of Western Australia. Unspeciated Cryptococcus spp. (from four quokkas), C. neoformans var. grubii (serotype A) (two quokkas) and C. magnus (one quokka) were isolated from the nasal lining of apparently healthy quokkas from RI. Cryptococcus neoformans var. grubii was isolated from animals captured in a human-populated area on RI. There was no significant effect of the presence of Cryptococcus on the results of haematology, blood chemistry, peripheral blood cell morphology or clinical examination. To the best of our knowledge, this is the first documented isolation of C. neoformans var. grubii (serotype A) and C. magnus in a free-ranging macropod in Western Australia. The public health implications of this finding should be further explored. 相似文献
102.
Taylor HA Brinton HC Bauer SJ Hartle RE Donahue TM Cloutier PA Michel FC Daniell RE Blackwell BH 《Science (New York, N.Y.)》1979,203(4382):752-754
The first in situ measurements of the composition of the ionosphere of Venus are provided by independent Bennett radio-frequency ion mass spectrometers on the Pioneer Venus bits and orbiter spacecraft, exploring the dawn and duskside regions, respectively. An extensive composition of ion species, rich in oxygen, nitrogen, and carbon chemistry is idenitified. The dominant topside ion is O(+), with C(+), N(+), H(+), and He(+) as prominent secondary ions. In the lower ionosphere, the ionzization peak or F(1) layer near 150 kilometers reaches a concentration of about 5 x l0(3) ions per cubic centimeter, and is composed of the dominant molecular ion, O(2)(+), with NO(+), CO(+), and CO(2)(+), constituting less than 10 percent of the total. Below the O(+) peak near 200 kilometers, the ions exhibit scale heights consistent with a neutral gas temperature of about 180 K near the terminator. In the upper ionosphere, scale heights of all species reflect the effects of plasma transport, which lifts the composition upward to the often abrupt ionopause, or thermal ion boundary, which is observed to vary in height between 250 to 1800 kilometers, in response to solar wind dynamics. 相似文献
103.
It has been suggested that Thaxteriola species and other minute, nonmycelial fungi associated with arthropods have phylogenetic relationships with the Laboulbeniales. However, direct development of the thallus of Thaxteriola from an ascospore of Pyxidiophora has now been discovered. Thaxteriola is specialized for dispersal by mites carried on pine bark beetles; other fungi dispersed by arthropods in this symbiotic assemblage rely primarily on arthropod specializations. 相似文献
104.
Development of the primary antibody repertoire 总被引:109,自引:0,他引:109
The ability to generate a diverse immune response depends on the somatic assembly of genes that encode the antigen-binding portions of immunoglobulin molecules. In this article, we discuss the mechanism and control of these genomic rearrangement events and how aspects of this process are involved in generating the primary antibody repertoire. 相似文献
105.
Andrew C. Smith Verena Pfahler Federica Tamburini Martin S. A. Blackwell Steven J. Granger 《植物养料与土壤学杂志》2021,184(1):25-34
Understanding the phosphate oxygen isotope (δ18O‐PO4) composition of bedrock phosphate sources is becoming ever more important, especially in areas of soil research which use this isotope signature as a proxy for biological cycling of phosphorus (P). For many of these studies, obtaining a sample of the source bedrock or applied mineral fertiliser for isotope analysis is impossible; meaning there is now a demand for a comprehensive characterisation of global bedrock δ18O‐PO4 to support this work. Here we compile δ18O‐PO4 data from a wide range of global bedrocks, including 56 new values produced as part of this study and a comprehensive overview of those within the previously existing literature. We present δ18O‐PO4 data from the range of major phosphatic lithologies alongside as much metadata for the samples as could be gathered. Much of the data comes from bedrocks of marine sedimentary origin (< 1 Ma = > +22‰, > 540 Ma = ≈ +12‰), but we also present data from bedrocks associated with guano (range: +19.5 to +15‰) and igneous deposits (range: +12 to –0.8‰), both of which have distinct δ18O‐PO4 signatures due to their formation mechanisms. We show that where repeat measurements of the same formation have been undertaken, regardless of method or exact sample location, there is an average within formation error of ± 1.25‰. This is important, as is constitutes a reasonable level of uncertainty for phosphorus cycling studies which need to estimate bedrock δ18O‐PO4 composition based on the literature. In combination, this data set presents 284 δ18O‐PO4 values from 56 countries; a comprehensive starting point for researchers interested in understanding bedrock end member δ18O‐PO4. 相似文献
106.
107.
Jerry Celumusa Dlamini Eyob Habte Tesfamariam Robert Dunn J. Evans Jane Hawkins Martin Blackwell Adrian Collins Laura Cardenas 《植物养料与土壤学杂志》2023,186(4):406-416
Background
Riparian buffers are primarily implemented for their water quality functions in agroecosystems. Their location in the agricultural landscape allows them to intercept and process pollutants from immediately adjacent agricultural land. Vegetated riparian buffers recycle soil organic matter, which elevates soil carbon (C), which upon processing, processes and releases carbon dioxide (CO2). The elevated soil C and seasonally anoxic environments associated with riparian buffers promote denitrification and fermentation, further increasing soil CO2 production.Aim
Against this context, a replicated plot-scale experiment was established at North Wyke, UK, to measure the extent of soil CO2 emissions in permanent pasture served by grass, willow, and woodland riparian buffers, as well as a no-buffer control.Methods
Soil CO2 was measured using the static chamber technique in conjunction with soil and environmental variables between June 2018 and February 2019.Results
Cumulative soil CO2 fluxes were in the descending order: woodland riparian buffer; 11,927.8 ± 1987.9 kg CO2 ha–1 > no-buffer control; 11,101.3 ± 3700.4 kg CO2 ha–1 > grass riparian buffer; 10,826.4 ± 2551.8 kg CO2 ha–1 > upslope pasture; 10,554.6 ± 879.5 kg CO2 ha–1 > willow riparian buffer; 9294.9 ± 1549.2 5 kg CO2 ha–1. There was, however, no evidence of significant differences among all treatments of the current study.Conclusions
Despite the lack of significant differences, the results from our short-term study show that the woodland riparian buffer had relatively larger soil CO2 emissions than the remainder of the other riparian buffers and the upslope pasture it serves. Our short-term findings may be useful in developing soil CO2 mitigation strategies through careful selection of riparian buffer vegetation and may be useful in calibrating mechanistic models for simulating such emissions from similar agro systems. 相似文献108.
109.
Strategies for educational action to meet veterinary medicine's role in biodefense and public health
Baker J Blackwell M Buss D Eyre P Held JR Ogilvie T Pappaioanou M Sawyer L 《Journal of veterinary medical education》2003,30(2):164-172
It is clear that the profession is not well prepared to respond to society's needs in bio-defense and public health. The imperatives that face the veterinary profession, as emphasized by the agenda for action conference deliberations that are reported in this issue of the journal, require action on many fronts, but possibly none more essential than to address how veterinary education needs to change to meet these challenges. Addressing these needs, participants at the agenda for action conference met in groups of 30 to 50 to shape approaches that would address these key questions. The 161 participants were broadly representative of government, private practice, corporate practice, organized veterinary medicine, and academia (Appendix A). Reported here are the results of those deliberations, with each of the seven sections written up by the discussion leader. Included in the participants were 20 students, representative of eight different veterinary colleges, who both participated in the group discussions and have presented their own report. 相似文献
110.
潘觉敏 《农业图书情报学刊》2011,23(5):158-161,164
从"农家书屋"的现状分析,探究"农家书屋"建设中所存在的问题,并提出进一步推进"农家书屋"科学可持续发展,从而在农村文化建设中发挥更大作用的对策。 相似文献