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The editor has retracted the article "Impacts of gully development on vegetation structure of Larrea tridentat-Ambrosia dumosa shrublands in southern Nevada" because the author of this article, Simon A. Lei, has admitted to data fabrication of articles similar to this one. The author was a visiting lecturer in the Education college at the University of Nevada, Las Vegas at the time of the publication of this article and is no longer affiliated with the university. It is recommended that authors no longer cite this article in any work.
Populations of the desert tortoise, Gopherus agassizii, have been severely impacted by upper respiratory tract disease (URTD), a potentially fatal condition caused by Mycoplasma agassizii. Because natural communities of microorganisms in animals may serve as barriers to infection by potential pathogens or may influence the course of a disease, we characterized the bacteria in the nasal passages of captive desert tortoises over an entire season. Tortoises housed in outdoor pens at the Adobe Mountain Wildlife Center in Phoenix, AZ, were divided into four groups: three healthy tortoises that were sampled monthly, three tortoises with signs of URTD that were sampled monthly, three healthy tortoises that were sampled bimonthly, and three healthy tortoises that were sampled once at the end of the season. At each sampling time, the health of each tortoise was assessed and the nares were probed with moistened sterile swabs. The bacteria on the swabs were suspended in sterile saline, serially diluted, and plated on tryptic soy agar medium. Total bacterial counts varied among tortoises from about 104 to 107 per ml and were usually higher in tortoises with signs of URTD. The proportions of different colony types varied from month to month within each tortoise. Although the microbial communities were dominated by pigmented Gram-positive cocci, we also found Gram-positive bacilli, Gram-variable coryneforms, and Gram-negative rods. Many of the same bacteria were recovered from both healthy and URTD tortoises, but others were unique to the URTD tortoises. This study indicates that the nasal passages of desert tortoises contain large continuously changing communities of bacteria and suggests that further analysis of these microorganisms may be useful in assessing the health or stress of populations of desert tortoises and the susceptibility of individual tortoises to URTD.
The Odonata of Ash Meadows National Wildlife Refuge (AMNWR) in southern Nevada were studied bimonthly in 2004 and 2005, revealing 32 species, a moderately high level of diversity for this relatively small, semi-isolated southern Nevada valley. Enallagma civile (Coenagrionidae) was the most regularly encountered species, followed by Rhionaeschna multicolor (Aeshnidae), Argia sedula (Coenagrionidae), and Pachydiplax longipennis (Libellulidae). Fourteen species were detected at three or fewer sites. The assemblage was co-dominated by taxa with ranges centered in North America and western North America, and 25% of the fauna were Mexican-neotropical. We report Macrodiplax balteata as new to Nevada's Odonata list, and six other new Nye County records. Odonata larval density/m2 and overall species richness (but not Shannon-Weiner diversity) were highest in the largest AMNWR wetlands, regardless of whether they were natural or anthropogenic, and were greater in two restored springs. Several of the most regularly detected larval Anisoptera (i.e., Erpetogomphus compositus and Erythemis collocata) were benthic ooze dwellers that have a flattened body morphology, which may allow them to avoid predation by non-native Procambarus clarki crayfish. Geomorphic restoration of springs may increase Odonata production, while augmentation of habitat area may increase species richness.
The surface geology of the Walnut Gulch Experimental Watershed (WGEW), Tombstone, Arizona, is dominated by fan deposits, but in southern and southeastern parts of WGEW a complex history of tectonism has resulted in igneous-intrusive and volcanic rocks, and highly disturbed Paleozoic and Mesozoic rocks in the Tombstone Hills. Soils, which are dominantly sand and gravel loams that vary from deep and well drained to thin and immature, are reflective of the rocks on which they formed. Large landforms are mostly dissected pediments and erosion surfaces, and hills of the volcanic and carbonate rocks. Episodic faulting that began in Precambrian time has resulted in complex geologic and geomorphic conditions that remain poorly understood owing to Basin and Range structural and depositional processes. Small-scale landforms of the watershed are individual hills, undissected remnants of alluvial fans (fan terraces), basin floors, alluvial fans, and recent alluvial sediment of stream channels, flood plains, and terrace-inset deposits. This paper combines the results of previous studies with recent field investigations and analysis of aerial photography to yield a summary of watershed conditions in support of ongoing research.
Pumas (Puma concolor) have long been considered transient species in southwestern Arizona. A sighting of three pumas in 2003 on the Kofa National Wildlife Refuge was the first verifiable record since 1944 and prompted further investigation into the presence and distribution of pumas on the refuge. Refuge personnel compiled 76 photographs of pumas since January 2004 and documented presence of five individuals, including a breeding female, in 2006 and 2007.
Here we describe an undergraduate microbiology laboratory exercise that examines differences between an anthropogenic and a natural soil microbial community. These two microbiological communities were analyzed using community level physiological profiling, a quantitative method for describing the microbial composition of the bacterial community using carbon source utilization. Specifically, Biolog EcoPlate Microplates were used to determine quantitatively the use of 31 different carbon sources for oxidative respiration by each community. Carbon source utilization was compared between communities and within communities using univariate statistical techniques. The utility of this exercise in teaching how statistical analysis is informative in the biological sciences is discussed, as well as strategies to include a range of statistical analysis from descriptive and univariate techniques to multivariate approaches.
White Muscle Disease (WMD) is a well-recognized degenerative muscle disease found in neonatal lambs. Pathogenesis is by deficiency of selenium and/or vitamin E. Morbidity and mortality in young lambs is common in areas where selenium and/or vitamin E are deficient. Arizona is not known as a deficient area yet older lambs are diagnosed with WMD during the hot summer months. Lambs affected with WMD cannot be brought to market and are a major economic concern for Arizona producers. We propose that the extreme heat experienced in central Arizona creates an unusually high demand for vitamin E not seen elsewhere. We propose this condition be termed Heat Stress Syndrome. Little is known about the prevention of heat induced WMD or Heat Stress Syndrome. This study will review the records of a local producer to investigate the efficacy of prophylactic megadose vitamin E treatment of vitamin E in reducing Heat Stress Syndrome (HSS). Specifically, the question of whether prophylactic treatment with vitamin E reduces the incidence of HSS in older lambs will be addressed. Such therapy options would be a welcome addition to the veterinarian's therapeutic portfolio and of economic interest throughout the region.
We report an unusual case of post-travel fever, extreme headache, chills, nausea, vomiting, profuse diarrhea and clinical sepsis. The patient had been in excellent health prior to a month-long rotation in Samoa and American Samoa where he had direct patient contact. He also traveled to remote villages, frequently ate local food and swam in both fresh and saltwater. Symptoms developed 5 days post return and on day eight the patient was hospitalized and resuscitated with intravenous fluids. Antibiotics administered empirically included IV levofloxacin, IV metronidazole and IV vancomycin. His condition gradually improved with normalization of lab values. However AST and ALT levels remained elevated. Despite advances in diagnosis, post-travel fevers remain a challenging clinical problem. Lessons learned from this patient's care will inform readers of current methods of diagnosis and treatment. Implications for travel to remote locales are discussed.
In vitro antibacterial activity of herbal products commonly used by the Mexican-American community was analyzed in this study. Traditional uses for these herbal products include general tonics and over-the-counter medications used to treat specific conditions or diseases. The present study examined the antibacterial activity of 74 herbal products using the disk diffusion method as part of the process of understanding the chemistry, toxicity and efficacy of these plant products. Ethanol extracts of the herbs were examined using a standard antimicrobial disk diffusion method. Extracts were tested against both Gram positive (Bacillus subtilis, Micrococcus luteus, and Staphylococcus aureus) and Gram negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. This present pilot study data with herbal products from Phoenix resulted in 4 plants being active against Staphylococcus aureus and 1 active against Pseudomonas aeruginosa out of the 74 plants tested. These results served to validate our procedures and indicate the need for the present study. Implications of these results for bioactivity and drug discovery potential of herbal products are discussed. This study serves as basis for further research on these herbs.