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Comparison of concentrations of Rhodococcus equi and virulent R. equi in air of stables and paddocks on horse breeding farms in a temperate climate.

REASONS FOR PERFORMING STUDY: Rhodococcoccus equi is a significant cause of bronchopneumonia in foals worldwide. Infection of the lungs is believed to result from inhalation of virulent R. equi in dust from contaminated environments. A measure of infectious risk in an environment is the level of airborne contamination. OBJECTIVES: To assess and compare the level of airborne virulent R. equi in paddocks and stables. METHODS: Air samples were collected sequentially over the 2003 foaling season from the paddocks and stables on 3 Irish horse breeding farms affected by R. equi pneumonia. Colony blotting and DNA hybridisation techniques allowed quantitation of virulent R. equi. RESULTS: The odds of detecting airborne virulent R. equi in stables were 173 times greater than in paddocks. The median airborne concentration of virulent R. equi was significantly higher (P < 0.001) in stables than in paddocks on all farms. These observations suggested that stables were high-risk areas for infection. CONCLUSIONS AND POTENTIAL RELEVANCE: Our results indicate that contaminated stables are a significant risk factor in the epidemiology of R. equi pneumonia on horse-breeding farms in a temperate climate, such as in Ireland. Management strategies that improve the air hygiene of stables, through better ventilation, use of less fragile bedding material and the use of fogging agents to reduce the airborne concentration of virulent R. equi, may reduce the incidence and severity of R. equi pneumonia on farms.

Actinomycetales Infections↗

Fitness of the marine parasitic nematode Anisakis simplex s. str. in temperate waters of the NE Atlantic.

In temperate waters of the NE Atlantic, third-stage larvae of Anisakis simplex sensu stricto collected from 3 paratenic host species were identified by restriction fragment length polymorphisms. The condition of wild larval infrapopulations was assessed by examining morphometric and growth characteristics. The differentiation patterns and the excretory/secretory products of larvae grown in vitro were also examined. An extensive morphometric, growth and differentiation variability was found between parasite larvae collected from different paratenic host sources. Nematode infrapopulation larvae from the squid comprise those smaller individuals with the lowest values of survival rates and moult success. It may be then concluded that the fitness of A. simplex s. str. larvae is not the best possible in the squid, which impaired the competitiveness of the parasite and its chances of developing into an adult. This suggests that the microenvironments impaired by the paratenic host may provide larval infrapopulations with unique ecological factors probably influencing its recruitment to the final host populations.

Animals↗

Cloning and characterization of the promoters of temperate mycobacteriophage L1.

Four putative promoters of the temperate mycobacteriophage L1 were cloned by detecting the beta-galactosidase reporter expression in E. coli transformants that carried L1 specific operon-fusion library. All of the four L1 promoters were also found to express differentially in the homologous environment of mycobacteria. Of the four promoters, two were suggested to be the putative early promoters of L1 since they express within 0 to 10 min of the initiation of the lytic growth of L1. One of the putative early promoters showed a relatively better and almost identical activity in both E. coli and M. smegmatis. By a sequence analysis, we suggest that the L1 insert that contained the stronger early promoter possibly carries two convergent E. coli sigma70-like L1 promoters, which are separated from each other by about 300 nucleotides. One of them is the early promoter of L1 as it showed a 100% similarity with the early Pleft promoter of the homoimmune phage L5. The second promoter, designated P4, was suggested for its appreciable level of reporter activity in the absence of the -10 element of the Pleft equivalent of L1. By analyzing most of the best characterized mycobacteriophages-specific promoters, including the L1 promoter P4, we suggest that both the -10 and -35 hexamers of the mycobacteriophage promoters are highly conserved and almost similar to the consensus -10 and -35 hexamers of the E. coli sigma70 promoters.

Amino Acid Sequence↗

Cloning and sequencing analysis of the repressor gene of temperate mycobacteriophage L1.

The wild-type and temperature-sensitive (ts) repressor genes were cloned from the temperate mycobacteriophage L1 and its mutant L1cIts391, respectively. A sequencing analysis revealed that the 131st proline residue of the wild-type repressor was changed to leucine in the ts mutant repressor. The 100% identity that was discovered between the two DNA regions of phages L1 and L5, carrying the same sets of genes including their repressor genes, strengthened the speculation that L1 is a minor variant of phage L5 or vice versa. A comparative analysis of the repressor proteins of different mycobacteriophages suggests that the mycobacteriophage-specific repressor proteins constitute a new family of repressors, which were possibly evolved from a common ancestor. Alignment of the mycobacteriophage-specific repressor proteins showed at least 7 blocks (designated I-VII) that carried 3-8 identical amino acid residues. The amino acid residues of blocks V, VI, and some residues downstream to block VI are crucial for the function of the L1 (or L5) repressor. Blocks I and II possibly form the turn and helix 2 regions of the HTH motif of the repressor. Block IV in the L1 repressor is part of the most charged region encompassing amino acid residues 72-92, which flanks the putative N-terminal basic (residues 1-71) and C-terminal acidic (residues 93-183) domains of L1 repressor.

Amino Acid Sequence↗

A point mutation at the C-terminal half of the repressor of temperate mycobacteriophage L1 affects its binding to the operator DNA.

The wild-type repressor CI of temperate mycobacteriophage L1 and the temperature-sensitive (ts) repressor CIts391 of a mutant L1 phage, L1cIts391, have been separately overexpressed in E. coli. Both these repressors were observed to specifically bind with the same cognate operator DNA. The operator-binding activity of CIts391 was shown to differ significantly than that of the CI at 32 to 42 degrees C. While 40-95% operator-binding activity was shown to be retained at 35 to 42 degrees C in CI, more than 75% operator-binding activity was lost in CIts391 at 35 to 38 degrees C, although the latter showed only 10% less binding compared to that of the former at 32 degrees C. The CIts391 showed almost no binding at 42 degrees C. An in vivo study showed that the CI repressor inhibited the growth of a clear plaque former mutant of the L1 phage more strongly than that of the CIts391 repressor at both 32 and 42 degrees C. The half-life of the CIts391-operator complex was found to be about 8 times less than that of the CI-operator complex at 32 degrees C. Interestingly, the repressor-operator complexes preformed at 0 degrees C have shown varying degrees of resistance to dissociation at the temperatures which inhibit the formation of these complexes are inhibited. The CI repressor, but not that of CIts391, regains most of the DNA-binding activity on cooling to 32 degrees C after preincubation at 42 to 52 degrees C. All these data suggest that the 131(st) proline residue at the C-terminal half of CI, which changed to leucine in the CIts391, plays a crucial role in binding the L1 repressor to the cognate operator DNA, although the helix-turn-helix DNA-binding motif of the L1 repressor is located at its N-terminal end.

DNA, Bacterial↗

Serologic evidence of Yersinia pestis infection in small mammals and bears from a temperate rainforest of north coastal California.

From 1983 to 1985, 463 serum samples from 11 species of mammals in Redwood National Park (RNP) (California, USA) were evaluated for antibodies to Yersinia pestis by the passive hemagglutination method. Yersinia pestis antibodies occurred in serum samples from 25 (36%) of 69 black bears (Ursus americanus), one (50%) of two raccoons (Procyon lotor), five (3%) of 170 dusky-footed woodrats (Neotoma fuscipes), and one (less than 1%) of 118 deer mice (Peromyscus maniculatus). Two hundred seventy-three flea pools, consisting of 14 species of fleas, were collected from small mammals and woodrat nest cups. Viable Y. pestis were not isolated from any of the flea pools. Significant between-year variations in the frequencies of seropositive bear or small mammal sera were not observed. A significantly higher frequency of plague antibodies was observed in bear sera taken during September collections. Frequencies of seropositive bear sera did not vary significantly by sex or age group of bears. Significant differences were not observed in the frequencies of seropositive small mammals by forest habitat type in which they were captured. This is the first report of Y. pestis infection in Redwood National Park, and the first detailed report of Y. pestis activity in a temperate rainforest.

Animals↗

Mercy: an insufficient motive for euthanasia. Catholic ethical tradition requires that we temper our motives with reason and care before acting.

Some experts argue that acts of assisted suicide and euthanasia are ethically appropriate because they are merciful. Compelling though it is, this argument is not sufficient for determining the morality of these acts. The ethical tradition that calls for mercy has never suggested that mercy is, by itself, a sufficient criterion for determining an act's moral appropriateness. Human motives are rarely, if ever, pure and objective. For that reason, our ethical tradition has insisted on tempering motives with reason and care. The criteria for determining when it is merciful to assist in another's suicide or engage in an act of euthanasia are, for all practical purposes, impossible to define. Commonly writers refer to a person's hopeless condition to justify the merciful response of assisted suicide or euthanasia. But unless we can agree on whether hopelessness is an objective or subjective reality, and until the criteria to define this reality are evident, it is difficult to see how assisted suicide or euthanasia can be a careful and reasoned expression of mercy. Only by examining one's intention can one judge whether an act that may appear to be merciful in a hopeless situation is appropriate. "Intention" refers to the reasoned decision or judgment one makes about a goal and the means used to achieve that goal. Even if we cannot control our emotional response (our motives) in a particular situation, we can control our judgment (our intentions). Within our moral tradition, we can be sure we are being merciful in a careful and reasoned way when we intend to protect and promote the good of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Altruism↗

The effect of aging on the impact resistance of heat tempered lenses.

Stock sperocylindrical lenses (125) with approximately 2.2-mm center thickness were bevel-edged to 48-mm size in the S-10 standard military lens shape. One time each, 25 lenses were drop balled directly after heat treatment; 25 after 3 months;25 after 6 months; 25 after 9 months; and the final 25 after 1 year. Comparing these samples against each other showed no statistical difference in breakage. All the surviving lenses were then drop balled repeatedly until broken or 25 impacts had been made. After 25 hits, 76.8% of the lenses did not break. There was no statistical difference in breakage when these results were compared with 125 heat-treated lenses of similar specifications that were drop balled for 25 trials, if not broken sooner, just after routine heat-treatment processing. Lenses of approximately 3.0-mm center thickness, with other aspects the same, were also treated. The effect of drop balling nonheat-tempered lenses of dimensions similar to the aged lenses was studied; the first drop had a casualty rate of 75%, and no lens survived more than 8 impacts.

Eyeglasses↗

[Genetic control of Vibrio cholerae pathogenicity: the temperate filamentous phage CTX, coding for cholera toxin and the "island of pathogenicity"].

Reviews modern data on the genetic control of the key factors of Vibrio cholerae pathogenicity: cholera toxin and toxin-coregulated adhesion pili. Pays special attention to the temperate filamentous CTX bacteriophage, whose genome contains structural genes of cholera toxin, and the "pathogenicity island" carrying tcp genes responsible for the most important factor of the human small intestine colonization with V. cholerae. Discusses the mechanism of coordinated regulation of the activity of the main genes of V. cholerae pathogenicity genes.

Bacteriophages↗

[Isolation and general characteristics of a group of Pseudomonas aeruginosa temperate phages].

Eighteen temperate phages were isolated from 38 natural strains of Pseudomonas aeruginosa. The phages belong to five heteroimmune groups according to the ability of lysogenic variants of the strains PAO1 and PAT2 to exclude the growth of the superinfecting phage. Phages of the II and V immunity groups are serologically similar; the remaining phages are not inactivated by antisera against phages B26 (II group) and K1338 (V group). Prophages of the II, IV, and V groups are induced by UV for vegetative growth. Phages belonging to different immunity groups vary in their morphology and particle size as was found by electron microscopy. Phages of the I, II, IV and V groups comprise one morphological type, those of the III group are of another morphological type. Phages of the IV group are not adsorbed on the bacterial mutants resistant to phages of the II and V immunity groups.

Bacteriophages↗

Detection of single-stranded cohesive ends in the genome of Bacillus thuringiensis temperate phage KK-88.

Cohesive ends (cos sites) were detected in the genome of temperate KK-88 phage in Bacillus thuringiensis after analysis of the phage DNA generated by the 3'-5' exonuclease activity of Klenow fragment of DNA polymerase I. In addition, unlike the 5'-protruding ends of coliphage lambda genome, the ends of KK-88 phage genome were found to be 3'-protruding. The restriction map of the phage genome was also constructed on the basis of position of the cos fragments.

Bacillus thuringiensis↗

The influence of seasonal factors on the incidence of peritonitis in continuous ambulatory peritoneal dialysis in the temperate zone.

Many factors contribute to the development of continuous ambulatory peritoneal dialysis (CAPD) peritonitis. The role of climate in CAPD peritonitis has received relatively little attention. We retrospectively analyzed the incidence of CAPD peritonitis according to temperature and relative humidity. Data from 80 patients were examined. The monthly mean temperature and relative humidity during study period varied between -3.4 degrees C and 25.4 degrees C and between 61% and 81%, respectively. In 1123 patient-months, 53 cases of peritonitis occurred. The occurrence of peritonitis paralleled temperature and relative humidity, being the highest (0.180 episodes/patient-month) in July (mean temperature, 24.6 degrees C; relative humidity, 81%) and lowest (0.013 episodes/patient-month) in November (mean temperature, 6.6 degrees C; relative humidity, 66%). Significant correlations were seen between the monthly frequency of CAPD peritonitis and temperature (r = 0.53, p < 0.05) and relative humidity (r = 0.59, p < 0.05). The incidence was higher in the warm season (months with a mean temperature > or = 15 degrees C, that is, May-September) than in the cold season (months with a mean temperature < 15 degrees C, that is, October-April), at 0.074 episodes/patient-month versus 0.024 episodes/patient-month, p < 0.05. We also found a tendency for gram-negative peritonitis to occur uniformly throughout the year, but for gram-positive peritonitis to increase during hot and humid months, especially the rainy month of July. Gram-positive organisms caused 50% of peritonitis from March to August, but just 17.7% from September to February. Gram-negative organisms caused 7.3% and 29.4% of peritonitis during the same periods (p < 0.05). The results indicate a clear seasonal change in the rate of CAPD peritonitis and in the causative micro-organisms. The observation that CAPD peritonitis increases in the season of high temperature and high humidity suggests the influence of climate on CAPD peritonitis in the temperate zone.

Climate↗

Effects of cultivation on N2O emission and seasonal quantitative variations of related microbes in a temperate grassland soil.

Laboratory and in situ experiments were done to investigate the influences of cultivation on temperate semi-arid grassland (for 17 years spring wheat planted once every two years without fertilisation) on soil N2O emission and quantitative variations of related soil microbes. In the laboratory (25 degrees C and soil moisture 18%), cultivation increased soil transformations of fertilizer nitrogen (100 micrograms N/g as NaNO3, urea, or as urea with dicyandiamide 1 microgram N/g). The N2O emissions from the cultivated and uncultivated soils with or without nitrogen additions were relatively low, and mainly originated from the nitrification. The soil N2O emission due to cultivation decreased somewhat upon no fertilization or NaNO3 addition, but significantly upon urea addition. The role of dicyandiamide as nitrification inhibitor was only considerable in the cultivated soil, and had small influence on decreasing N2O emission in the two soils. The influence of cultivation on soil N2O emission was also reflected by the number variations of microbes related with soil nitrogen transformation in the two soils. Compared to the uncultivated grassland, in situ ammonifiers and denitrifiers in the cultivated grassland quantitatively averagely increased, and aerobic no-symbiotic azotobacters were quantitatively similar, leading to the continued decrease of organic matter content and the decrease of N2O emission from the cultivated grassland soil.

China↗

[Landscape changes of ecotone of temperate and sub-tropical zone and its ecological importance].

The change process of ecotone of temperate and subtropical zone and its effect on development, transformation and permeation of chinese agriculture and techniques were discussed in this paper from the viewpoint of landscape ecology. In historical time, the boundary of the ecotone changed northward and southward as climate changed, which changed southward 1-2 latitude in cold period and northward 1-2 latitude in warm period. The ecotone had an obvious environment diversity and strong sensibility, and played important role as a landscape conduit and barrier in aspects of chinese agricultural heterogeneous permeation and heterogeneity creation of agricultural techniques and cultures.

Agriculture↗

[Stable carbon isotope characteristics of some woody plants in warm temperate zone].

It was found that the delta 13C values of the foliar, trunk, flower, and fruit of some woody plants in broad-leaved forest in warm temperate zone were affected by many factors, and showed a great interspecific difference and temporal and spatial heterogeneity. The intraspecific variation of delta 13C values was also great, with the order of Vitex negundo var. heterophylla 6.549@1000(-22.226@1000(-)-28.775@1000), Fraxinus rhynchophylla 5.706@1000(-23.687@1000(-)-29.393@1000), Jugans mandshurica 5.229@1000 (-26.146@1000-31.375@1000), Quercus liaotungensis 3.333@1000 (-24.324@1000(-)-27.657@1000), Syringa pekinensis 2.414@1000(-25.655@1000(-)-28.070@1000), and Prunus armeniaca var. ansu 2.296@1000 (-23.436@1000(-)-26.432@1000). Different organs of the same species had different delta 13C values: trunk and root barks had the low, while xylem had the highest delta 13C value. According to the relationship analysis between delta 13C value of Prunus armeniaca var. ansu xylem and environment factors, it was found that delta 13C value was strongly affected by annual mean temperature and followed by annual precipitation, mean temperature and precipitation in growth season.

Carbon Isotopes↗

[Temperate bacteriophage ZF40 of Erwinia carotovora: phage particle structure and DNA restriction analysis].

Structural organization of the temperate bacteriophage ZF40 of Erwinia carotovora was studied. Phage ZF40 proved to be a typical member of the Myoviridae family (morphotype A1). Phage particles consist of an isometric head 58.3 nm in diameter and a contractile 86.3-nm-long tail with a complex basal plate and short tail fibers (31.5 nm). Phage tail sheath, a truncated cone in shape, is characterized by specific packaging of structural subunits. The ZF40 phage genome is 45.8 kb in size, as determined by restriction analysis, and contains DNA cohesive ends. The ZF40 phage of Erwinia carotovora is assumed to be a new species of bacteriophages specific for enterobacteria.

DNA, Viral↗

Chilling resistances of isolates of Pythium ultimum var. ultimum from the Arctic and Temperate Zones.

Chilling resistances in moss pathogenic fungi, Pythium ultimum var. ultimum, from Longyearbyen, Svalbard (78 degree N, 15 degree E), located in the Arctic Zone and in the same isolates from Temperate Zone, were determined. Both strains had similar optimum growth temperatures. However, the strains from Svalbard could grow and survive at 0 - 5 degrees C. In addition, chilling treatment induced irregular mycelial morphology in the Arctic isolates. On the other hand, the isolates from Japan did not grow at temperatures below 5C and were destroyed after chilling stress (0 degree C for 3 days or at 4 degrees C for 1 week). The results suggested that isolates from Svalbard highly adapted to the severe spring condition in Polar environments.

Arctic Regions↗