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At least 1,423 records · Page 79Linked to original sources
PubMed1996

Identification of root rot fungi in nursery seedlings by nested multiplex PCR.

The internal transcribed spacer (ITS) of the ribosomal DNA (rDNA) subunit repeat was sequenced in 12 isolates of Cylindrocladium floridanum and 11 isolates of Cylindrocarpon destructans. Sequences were aligned and compared with ITS sequences of other fungi in GenBank. Some intraspecific variability was present within our collections of C. destructans but not in C. floridanum. Three ITS variants were identified within C. destructans, but there was no apparent association between ITS variants and host or geographic origin. Two internal primers were synthesized for the specific amplification of portions of the ITS for C. floridanum, and two primers were designed to amplify all three variants of C. destructans. The species-specific primers amplified PCR products of the expected length when tested with cultures of C, destructans and C. floridanum from white spruce, black spruce, Norway spruce, red spruce, jack pine, red pine, and black walnut from eight nurseries and three plantations in Quebec. No amplification resulted from PCR reactions on fungal DNA from 26 common contaminants of conifer roots. For amplifications directly from infected tissues, a nested primer PCR using two rounds of amplification was combined with multiplex PCR approach resulting in the amplification of two different species-specific PCR fragments in the same reaction. First, the entire ITS was amplified with one universal primer and a second primer specific to fungi; a second round of amplification was carried out with species-specific primers that amplified a 400-bp PCR product from C. destructans and a 328-bp product from C. floridanum. The species-specific fragments were amplified directly from infected roots from which one or the two fungi had been isolated.

Base Sequence↗
PubMed1997

Molecular microbial diversity in soils from eastern Amazonia: evidence for unusual microorganisms and microbial population shifts associated with deforestation.

Although the Amazon Basin is well known for its diversity of flora and fauna, this report represents the first description of the microbial diversity in Amazonian soils involving a culture-independent approach. Among the 100 sequences of genes coding for small-subunit rRNA obtained by PCR amplification with universal small-subunit rRNA primers, 98 were bacterial and 2 were archaeal. No duplicate sequences were found, and none of the sequences had been previously described. Eighteen percent of the bacterial sequences could not be classified in any known bacterial kingdom. Two sequences may represent a unique branch between the vast majority of bacteria and the deeply branching, predominantly thermophilic bacteria. Five sequences formed a clade that may represent a novel group within the class Proteobacteria. In addition, rRNA intergenic spacer analysis was used to show significant microbial population differences between a mature forest soil and an adjacent pasture soil.

Bacteria↗
PubMed2001

Comparison of endotoxin exposure assessment by bioaerosol impinger and filter-sampling methods.

Environmental assessment data collected in two prior occupational hygiene studies of swine barns and sawmills allowed the comparison of concurrent, triplicate, side-by-side endotoxin measurements using air sampling filters and bioaerosol impingers. Endotoxin concentrations in impinger solutions and filter eluates were assayed using the Limulus amebocyte lysate assay. In sawmills, impinger sampling yielded significantly higher endotoxin concentration measurements and lower variances than filter sampling with IOM inhalable dust samplers. Analysis of variance for repeated measures showed that this association remained after controlling for other factors such as replicate, sawmill, sawmill operation, wood type, and interaction terms. Endotoxin concentrations in the swine barns were 10-fold higher on average than in sawmills. These samples demonstrated comparable endotoxin concentration estimates for impinger and filter methods although the variability was lower using the impinger method. In both occupational settings, side-by-side replicates were more uniform for the impinger samples than for the filter samples. This study demonstrates that impinger sampling is an acceptable method for quantitation of area endotoxin concentrations. Further, when sampling is performed with impingers for airborne microorganism quantitation, these same impinger solutions can yield valid endotoxin exposure estimates, negating the need for additional filter sampling.

Air Pollutants, Occupational↗
PubMed2003

Effects of litter addition on ectomycorrhizal associates of a lodgepole pine (Pinus contorta) stand in Yellowstone National Park.

Increasing soil nutrients through litter manipulation, pollution, or fertilization can adversely affect ectomycorrhizal (EM) communities by inhibiting fungal growth. In this study, we used molecular genetic methods to determine the effects of litter addition on the EM community of a Pinus contorta stand in Yellowstone National Park that regenerated after a stand-replacing fire. Two controls were used; in unmodified control plots nothing was added to the soil, and in perlite plots perlite, a chemically neutral substance, was added to maintain soil moisture and temperature at levels similar to those under litter. We found that (i) species richness did not change significantly following perlite addition (2.6 +/- 0.3 species/core in control plots, compared with 2.3 +/- 0.3 species/core in perlite plots) but decreased significantly (P < 0.05) following litter addition (1.8 +/- 0.3 species/core); (ii) EM infection was not affected by the addition of perlite but increased significantly (P < 0.001) in response to litter addition, and the increase occurred only in the upper soil layer, directly adjacent to the added litter; and (iii) Suillus granulatus, Wilcoxina mikolae, and agaricoid DD were the dominant organisms in controls, but the levels of W. mikolae and agaricoid DD decreased significantly in response to both perlite and litter addition. The relative levels of S. granulatus and a fourth fungus, Cortinariaceae species 2, increased significantly (P < 0.01 and P < 0.05, respectively) following litter addition. Thus, litter addition resulted in some negative effects that may be attributable to moisture-temperature relationships rather than to the increased nutrients associated with litter. Some species respond positively to litter addition, indicating that there are differences in their physiologies. Hence, changes in the EM community induced by litter accumulation also may affect ecosystem function.

Aluminum Oxide↗
PubMed2004

A study of logger fatalities from 1992-2000.

OBJECTIVES: To determine if certain loggers are at increased risk of death during logging operations. METHODS: Statistical analysis of 780 logger fatalities for a nine year period (1992-2000). RESULTS: The major findings are: (1) treefallers suffer nearly 63% of all fatalities, (2) the region where the fatality occurred and the size of the employer were not significant factors that contributed to a high percentage of treefaller fatalities, and (3) the Northeast and Midwest regions showed a higher percentage of fatalities compared with the South and West regions. CONCLUSIONS: Overall, the logger fatality rate for 1992-2000, compared with 1980-88 has decreased slightly; however, treefallers continue to be the group of loggers who suffer the highest fatality rate.

Accidents, Occupational↗
PubMed2002

Effect of de-industrialisation on working conditions and self reported health in a sample of manufacturing workers.

STUDY OBJECTIVE: To explore the impact of de-industrialisation over a 20 year period on working conditions and health among sawmill workers, in the province of British Columbia (BC), Canada. DESIGN AND SETTING: This investigation is based on a sample of 3000 sawmill workers employed in 1979 (a year before the beginning de-industrialisation) and interviewed in 1998. The sample was obtained by random selection from an already gathered cohort of approximately 28 000 BC sawmill workers. Change in working conditions from 1979 to 1998 are described. Self reported health status, in 1998, was used as a dependent variable in logistic regression after controlling for confounders. MAIN RESULTS: Downsizing in BC sawmills eliminated 60% of workers between 1979 and 1998. Working conditions in 1998 were better for those who left the sawmill industry and obtained re-employment elsewhere. Workers who remained employed in restructuring sawmills were approximately 50% more likely to report poor health than those re-employed elsewhere. CONCLUSIONS: Working conditions and health status were better for workers who, under pressure of de-industrialisation, left the sawmill industry and obtained re-employment outside this sector.

Adult↗
PubMed2006

Costs and compensation of work-related injuries in British Columbia sawmills.

OBJECTIVE: To estimate the costs of work-related injury in a cohort of sawmill workers in British Columbia from the perspective of the workers' compensation system. METHODS: Hospital discharge records were extracted from 1989 to 1998 for a cohort of 5786 actively employed sawmill workers. A total of 173 work-related injury cases were identified from these records using the International classification of diseases-ninth revision (ICD-9) external cause of injury codes and the responsibility of payment schedule. Workers' compensation records were extracted and matched with hospital records by dates and ICD-9 diagnosis codes. All costs were converted into 1995 constant Canadian dollars using the Provincial General Consumer Price Index for the non-healthcare costs and Medical Consumer Price Index for the healthcare costs. A 5% discounting rate was applied to adjust for the time value of money. For the uncompensated cases, costs were imputed from the compensated cases using the median cost for a similar nature of injury. RESULTS: 370 hospitalisation events due to injury were captured, and by either of the two indicators (E Codes or payment schedules), 173 (47%) hospitalisation events due to injury, were identified as work related. The median healthcare cost was 4377 dollars and the median non-healthcare cost was 16,559 dollars for a work-related injury. The median non-healthcare and healthcare costs by injury were falls, 19,978 dollars and 5185 dollars; struck by falling object, 32,398 dollars and 8625 dollars; struck against, 12,667 dollars and 5741 dollars; machinery related, 26,480 dollars and 6643 dollars; caught in or between, 24,130 dollars and 4389 dollars; and overexertion, 7801 dollars and 2710 dollars. The total cost was 10,374,115 dollars for non-healthcare and 1,764,137 dollars for healthcare. The compensation agency did not compensate 874,871 dollars (8.4%) of the non-healthcare costs and 200,588 dollars (11.4%) of the healthcare costs. CONCLUSION: Eliminating avoidable work-related injury events can save valuable resources.

Accidents, Occupational↗