Soil lead concentrations in residential Minnesota as measured by ICP-AES

A total of 2454 samples were collected to evaluate the degree, extent, and distribution of Pb contaminated soil in Minnesota. Samples were collected primarily at locations where susceptible populations were concentrated. Soil Pb concentrations in chilldren's play areas, urban gardens, and at open sites were generally below 100 μg g ^?1 when Pb painted structures were absent. Street side and yard soils typically had Pb concentrations between 10 to 300 μg g^?1, with samples collected near major highways or Pb painted structures exhibiting greater values. The most severely contaminated soils were found in localized areas around the foundations of private residences, where concentrations up to 20 136 μg g^?1 were detected. Exterior Pb based house paint is the major Pb source in these soils, and its presence greatly influences the distribution of contaminated soil in individual yards. Contamination attributable to autoemissions is less concentrated but more widespread than contamination from paint. A higher proportion of soils exceeding 1000 wg g^?1 Pb was found in large cities than elsewhere. However, a sufficient number were detected in small cities and rural areas to confirm that high soil Pb levels are not exclusively an urban phenomenon. By examining the degree, extent, and distribution of Pb contaminated soils in Minnesota, this study provides information useful in guiding response actions to reduce children's exposure to Pb by this pathway.     

Public acceptance as a determinant of management strategies for bovine tuberculosis in free-ranging U.S. wildlife

Mycobacterium marinum is a free-living bacterium that infects fish and amphibians, but is also an opportunistic pathogen in humans. Although in previous studies, the bacterium has shown a small number of Variable Number of Tandem Repeat (VNTR) polymorphic loci, the discriminatory power of the known VNTR loci is unlikely to be sufficient to distinguish such a globally ubiquitous waterborne microorganism, which has a presumably high genetic variance. The object of this study was to test M. marinum isolates from east China for strain diversity using previously described loci as well as novel VNTR loci, and to identify more discriminating VNTR loci that could enrich the genotyping tools for M. marinum. We found that 7 of the 12 tested VNTR loci, of which 5 were known loci and 2 loci were newly identified, showed good discriminatory power for the 14 M. marinum clinical isolates (Hunter-Gaston Index [HGI] value=0.990). The pathogenicity of isolates representing different VNTR clusters was also studied in a zebrafish (Danio rerio) infection model; in this model, 6 isolates representing 4 VNTR clusters induced chronic infections, whereas the American strain ATCC BAA-535 caused acute and lethal infections.     

Organic matter dynamics in a temperate forest soil following enhanced drying

Climate models predict an increase in global surface temperature and a change in precipitation intensity during this century. For Europe, extended drought periods followed by heavy rainfall are expected. The consequences for soil organic matter (SOM) dynamics are poorly understood. In this study, we investigated the effect of changing soil moisture regime on SOM quality under field conditions. For this purpose, a throughfall exclusion (TE) experiment was conducted in the summers 2006 and 2007 on a Haplic Podzol under a 140 years old Norway spruce stand using a roof installation followed by re-wetting compared to non-manipulated control plots. Total organic carbon, lignin (stable carbon pool), plant and microbial sugars (labile carbon pool) and microbial biomass (phospholipid fatty acids) were determined before, during and after the experiment in the L, O, A and B horizons. No significant treatment effects could be observed for SOM quantity. Amounts of lignin and soil microbial biomass were also not affected by the moisture regime but structure of soil microbial community. In the L and organic layers, gram + bacteria and actinomycetes were reduced during water stress, while gram- bacteria, fungi and protozoa increased during drought. Warmer and drier weather led to a dominance of fungi while a cooler and moister regime favoured bacteria, at least in the L horizon. An increasing PLFA (cy17:0 + cy19:0)/(16:1ω7c + 18:1ω7c) ratio in the O layer and A horizon suggests that the microbes suffered from water stress in these horizons. This agrees with a decreasing contribution of microbial sugars to SOM with decreasing water content in the O and A horizons. Although the original plant material exhibited increasing plant sugar content with increasing dryness, the contribution of the plant sugars to total soil organic carbon (SOC) generally decreased with decreasing water content. Physical-chemical changes of soil structure can theoretically change the sugar extractability from soils and/or chemical changes of sugars structure can probably affect the analysis. Therefore, chemical alteration and stabilization could be responsible for sugar decrease in soil with increasing dryness explaining the contrast compared to the original plant material.     

Serum vitamin A concentrations in captive sea otters (Enhydra lutris)

Individual dietary preferences and difficulty with animal training create challenges and nutritional concerns when evaluating a captive sea otter (Enhydra lutris) diet. The importance of vitamin A within the body reflects the necessity that it be ingested in adequate amounts to ensure optimal health. To compare levels of serum vitamin A concentrations from captive sea otters on daily oral vitamin A supplementation, serum samples from eight adult sea otters from three institutions were evaluated for serum vitamin A concentrations. The eight animals were fed a total of four different diets and received oral supplementation via three different methods. Multiple diet items were analyzed for vitamin A content and were found to have low to nondetectable levels of vitamin A. Oral vitamin A supplementation, as a slurry with dietary items, was shown to be effective and a mean serum concentration of approximately 170 +/- 51 microg/L was obtained for serum vitamin A concentrations in captive sea otters. Captive diets can be modified to increase vitamin A concentration and supplementation and, if accepted, can be used as a means to ensure adequate vitamin A intake.     

Bovine leukocyte phagocytosis and bacteria killing monitored by intracellular acridine orange fluorescence and extracellular fluorescence quenching

The time course of phagocytosis and intracellular killing of serum-opsonized Escherichia coli K12 and Staphylococcus aureus SG511 by glass-adherent bovine peripheral blood polymorphonuclear leukocytes (PMNLs) and cultured monocytes (macrophages) was monitored by fluorescence microscopy of single cells using the acridine orange (AO)/crystal violet (CV) technique. After interaction of glass-adherent leukocytes (20, 40, 60 min, 37 degrees C) with opsonized bacteria, cells were stained with the fluorescent dye AO. Living bacteria stained green, dead bacteria stained orange. The addition of CV to AO-stained bacteria quenched the fluorescence of extracellular bacteria only. CV does not penetrate living bovine PMNLs which allows the discrimination of ingested (fluorescent) and extracellular (nonfluorescent) bacteria during attachment and phagocytosis of bacteria by adherent PMNLs. We investigated quantitatively phagocytosis and intracellular killing of serum-opsonized bacteria by bovine PMNLs from 22 bulls of 4 different Swiss dairy breeds. Within 60 min maximum uptake (approximately 12 bacteria/PMNL) and killing (approximately 80%) of serum-opsonized Escherichia coli K12 and Staphylococcus aureus SG511 were achieved. The AO/CV technique was also used to quantify the uptake and intracellular killing of serum-opsonized Escherichia coli K12 by cultured monocytes (macrophages). Within 60 min maximum uptake of bacteria (approximately 16/MO) was achieved; approximately 83% of bacteria were killed.     

Fish diseases in Switzerland. A statistical evaluation of the diagnostic materials of the fish research laboratory from 1979-1988. I. General aspects]

The entire diagnostic material of the Fish Disease Laboratory at the University of Berne from 1979 to 1988, a total of more than 3800 cases, is presented. Not included is material of import controls and material from experimental work. The following criteria were evaluated: fish species, origin and length of fish, season, infectious and noninfectious diseases. Furthermore, the results were investigated for changes of the composition of fish species and number of diseases within the ten-year period and for a seasonal influence on the outbreak of diseases. More than 40% of all fish investigated were rainbow trout, followed by brown trout, omamental fish and cyprinids. Over 40% of fish originated from private fishfarms whereas 20% were of governmental origin (governmental fishfarms, rivers, lakes) and 20% from aquaria. Parasites were present in more than 40% of all cases. Bacterial infections were diagnosed in nearly 30%, viral infections in 6% and fungal diseases in 5% of all cases. 20% of all cases concerning noninfectious diseases were caused by unfavourable environmental conditions whereas the incidence of diseases related to nutrition was less than 10%. The occurrence of the different diseases was waxing and waning over the period of ten years but no definite tendencies could be emphasized. However, most of the diseases investigated demonstrated a significant seasonal influence.     

Further investigation of lead exposure as a potential threatening process for a scavenging marsupial species

There is a growing recognition of the harmful effects of lead exposure on avian and mammalian scavengers. This can lead to both lethal and non-lethal effects which may negatively impact wildlife populations. Our objective was to assess medium-term lead exposure in wild Tasmanian devils (Sarcophilus harrisii). Frozen liver samples (n = 41), opportunistically collected in 2017–2022, were analysed using inductively coupled plasma mass spectrometry (ICP-MS) to determine liver lead concentrations. These results were then used to calculate the proportion of animals with elevated lead levels (>5 mg/kg dry weight) and examine the role of explanatory variables that may have influenced the results. The majority of samples analysed were from the south-east corner of Tasmania, within 50 km of Hobart. No Tasmanian devil samples were found to have elevated lead levels. The median liver lead concentration was 0.17 mg/kg (range 0.05–1.32 mg/kg). Female devils were found to have significantly higher liver lead concentrations than males (P = 0.013), which was likely related to lactation, but other variables (age, location, body mass) were not significant. These results suggest that wild Tasmanian devil populations currently show minimal medium-term evidence of exposure to lead pollution, although samples were concentrated in peri-urban areas. The results provide a baseline level which can be used to assess the impact of any future changes in lead use in Tasmania. Furthermore, these data can be used as a comparison for lead exposure studies in other mammalian scavengers, including other carnivorous marsupial species.