Cultivation of the agarophyte Gelidium pristoides in Algoa Bay,South Africa

Biofilms were allowed to develop on wooden slides of the River Red Gum (Eucalyptus camaldulensis Dehnh., Myrtaceae) submerged in two billabongs of south-eastern Australia. The slides were placed in the photic zone and the aphotic zone, and the biofilms sampled after eight week's growth over the summer of 1989–1990 and winter of 1990. Bacterial numbers, estimated with epifluorescence microscopy, ranged from 4–78 × 10⁶ cells cm^–2. Bacteria were more abundant in the photic zone than the aphotic zone, and more abundant in summer than winter. Fewer than 0.5% of the bacteria could be cultivated on nutrient agar plates. Concentrations of phospholipids ranged from 8–79 ng cm^–2, which corresponded to bacterial abundances of 2–17 × 10⁶ cells cm^–2. Fifty five phospholipid fatty acids (PLFA) were identified, of which 16:0 (13–29% of total PFLA) was the most common. Other abundant PFLA included 16:17c (6–28%), 18:26 (3–16%), 18:33 (4–12%), 18:19c (3–5%), 18:l7c (5–11%) and 18:0 (2–8%). Minor PLFA included 14:0, i and a 15:0, 15:0, 16:l5c, 16:113c, 18:36, 18:43, 20:46 and 20:53. The PLFA profiles of the biofilms were quite different from those of the sediments and plankton. There was a clear distinction between the PLFA profiles of summer and winter biofilms, but less evidence for unequivocal site or light-regime effects.     

Growth of arbuscular mycorrhizal mycelium in calcareous dune sand and its interaction with other soil microorganisms as estimated by measurement of specific fatty acids

Fatty acid analysis was used for determining the extent of the development of the external mycelium of AM fungi (mixed inoculum from a sand dune) growing from roots of Festuca rubra and Plantago lanceolata in calcareous dune sand. The plants were raised in chambers specially designed to permit the growth of AM mycelium in root-free compartments. In two separate experiments, growth of external mycelium in the root-free compartments was detected and the amount of mycelium was estimated using the indicator of AM fungal biomass, phospholipid fatty acid (PLFA) 16:15. The results showed that the PLFA 16:15 was suitable for estimating the mycelium emerging from the mixed inoculum obtained from the field roots of F. rubra and P. lanceolata.The PLFA 16:15 showed external mycelium to become established in the root-free compartments within a period of 3 weeks and the amount of mycelium to continue to increase at 6 and 9 weeks. Increases in neutral lipid fatty acid (NLFA) 16:15 (indicator of storage lipids) over time were inconsistent between the two experiments, but appeared to follow patterns of sporulation in each experiment.In both experiments, the root-free compartment was colonised by saprophytic fungi to a greater extent in the case of non-mycorrhizal than of AM treatment, as indicated by an increase in PLFA 18:26,9 (indicator of saprophytic fungi). The absence of an increase in the case of AM treatment indicates that AM fungal mycelium can negatively affect the growth of saprophytic fungi in this soil type. This result was, however, only weakly supported by measurements of ergosterol content. The analysis of bacteria specific PLFAs showed that bacterial biomass was not affected by the AM mycelium.     

Physical mechanisms by which low-frequency magnetic fields can affect the distribution of counterions on cylindrical biological cell surfaces

Effects of dc and low-frequency ac magnetic fields on the motion and distribution of counterions on surfaces of cylindrical biological cells are examined. Magnetic fields along the cell axis as well as perpendicular to it are considered. When a dc magnetic field of any physically realizable magnitude is parallel to the cell axis it has no effect on ion motion, since the resulting Lorentz force is much smaller than the counterion-to-ion attractive force. However a dc magnetic field perpendicular to the cell surface will distort any preexisting ion motion and the resulting current (i) perpendicular to the original motion will be much larger than any current induced by a low-frequency ac magnetic field of the same magnitude as the dc field and parallel to it. Nevertheless i will still be much smaller than the current i_o constituting the original ion motion since (i/i_o)=/, where is the ion cyclotron frequency and the effective counterion collision frequency. With no preexisting coherent ion motion (i_o=0) the circulating current induced by a sinusoidally time-varying magnetic field parallel to the cell axis will be well below thermal fluctuation noise as long as only a single cell is considered; however when even an infinitesimal exchange of ions between adjacent cells is assumed the magnetic field will cause a redistribution of counterions on the cell surface. The resulting steady-state distribution becomes independent of the frequency of the applied magnetic field () when , where is 1/2 of the relaxation frequency for counterion diffusion. On the basis of these results it is suggested that whenever modification of cell behavior in response to application of a low-frequency magnetic field is established, measurements of dielectric permittivity versus frequency of the cell preparation be performed. Redistribution of counterions on the cell surface would be a likely cause if the noted effect becomes independent of the frequency of the applied magnetic field above the counterion dielectric relaxation frequency. It is also suggested that in magnetic field exposure of cell preparations the size of the sample (e.g. diameter of Petri dish) and direction of the magnetic field relative to average cell orientation can critically affect experimental results.     

Characterization of<Emphasis Type="Italic"> Pseudomonas</Emphasis> sp. HK-6 cells responding to explosive RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine)

The cellular responses of Pseudomonas sp. HK-6 to explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) have been extensively analyzed in this study. The stress shock proteins, which might contribute to enhancing the cellular resistance to the cytotoxic effect of RDX, were induced at different concentrations of RDX used as a substrate for cell culture of Pseudomonas sp. HK-6. The proteins were identified as 70-kDa DnaK and 60-kDa GroEL by SDS-PAGE and Western blot using the anti-DnaK and anti-GroEL monoclonal antibodies. The stress shock proteins induced by RDX were found to increase in proportion to the RDX concentration used for this work. Analysis of membrane fatty acids of strain HK-6 following exposure to RDX showed that the amounts of dominant lipids 16:1 7c/15:0 iso 2OH, 16:0 and 18:1 7c/9t/12t decreased substantially or were not detected in the cells exposed to RDX, while amounts of lipids 10:0 iso, 14:1 5c/5t and 16:10 methyl increased dramatically. Scanning electron microcopy analyses revealed the presence of perforations and irregular rod shapes with wrinkled surfaces for cells treated with 0.135 mM RDX for 12 h, suggesting that RDX has a substantial cytotoxic impact on cells of strain HK-6.     

Seasonal changes in the microbial community of a salt marsh, measured by phospholipid fatty acid analysis

Microbial activity within the environment can have distinct geochemicaleffects, and so changes in a microbial community structure can result ingeochemical change. We examined seasonal changes in both the microbialcommunityand the geochemistry of an inter-tidal salt marsh in north-west England tocharacterise biogeochemical processes occurring at this site.Phospholipid fatty acid (PLFA) analysis of sediment samples collected atmonthly intervals was used to measure seasonal changes in microbial biomass andcommunity structure. The PLFA data were analysed using multivariate techniques(Ward's method and the Mahalanobis distance metric), and we show that the useofthe Mahalanobis distance metric improves the statistical analysis by providingdetailed information on the reasons samples cluster together and identifyingthedistinguishing features between the separate clusters. Five clusters of likesamples were defined, showing differences in the community structure over thecourse of a year.At all times, the microbial community was dominated by PLFA associated withaerobic bacteria, but this was most pronounced in summer (August). Theabundanceof branched fatty acids, a measure of the biomass of anaerobes, started toincrease later in the year than did those associated with aerobes and thefungalbiomarker 18:26 showed a brief late-summer peak.The salt marsh remained mildly oxic throughout the year despite the increase inmicrobial respiration, suggested by the large increases in the abundance ofPLFA, in the warmer months. The conditions therefore remained most favourablefor aerobic species throughout the year, explaining their continual dominanceatthis site. However, as the abundance of PLFA synthesised by anaerobesincreased,increases in dissolved Mn concentrations were observed, which we suggest weredue to anaerobic respiration of Mn(IV) to Mn(II). Overall, the geochemicalconditions were consistent with the microbial community structure and changeswithin it.     

Characteristics of [125I]ω-conotoxin labeling using bifunctional cross linker DSP in crude membranes from chick brain

Characteristic of [¹²⁵I]-conotoxin (-CgTX) labeling using bifunctional cross linker (dithio bis[succinimidyl propionate]: DSP) was systematically investigated in crude membranes from chick whole brain. [¹²⁵I]-CgTX specifically labeled 216 kDa as a main and 236 kDa as a minor bands in the crude membranes under non-reduced condition, but not labeled under reduced condition. We investigated the effect of various Ca channel antagonists on [¹²⁵I]-CgTX labeling with DSP in detail, and found that there is a strong correlation between the effects of Ca channel antagonists on [¹²⁵I]-CgTX labeling of the 216 kDa band and specific [¹²⁵I]-CgTX binding. These results suggest that labeling of the 216 kDa band under non-reduced condition with [¹²⁵I]-CgTX using DSP involves the specific binding sites of [¹²⁵I]-CgTX, perhaps including one of the neuronal N-type Ca channel subunits in the crude membranes.     

Cleavage of lambda repressor and synthesis of RecA protein induced by transferred UV-damaged F sex factor

Summary Transfer of a UV-damaged F sex factor to a recipient lysogen induces prophage development. Under these conditions RecA protein synthesis was induced and repressor cleaved, as observed upon direct induction, that is, when the recipient lysogen was directly exposed to UV-light. The efficiency of induction of RecA protein synthesis in recipient bacteria which had received an irradiated F-lac factor was about 80% of that measured upon direct induction. We observed the simultaneous disappearance of repressor and a slight production of cleavage fragments; quantitation by densitometric scanning of the autoradiogram after correction for the efficiency of transfer indicated that 55% of repressor was cleaved. Transfer of UV-damaged Hfr DNA failed to induce RecA protein synthesis. A phage vector carrying oriF, the cloned origin of F plasmid replication, after exposure to UV-light and infection of a recipient lysogen, induced RecA protein synthesis and a moderate but significant cleavage of repressor. Indirect induction by UV-damaged F sex factor or phage oriF resulted in biochemical cellular reactions similar to those observed upon direct induction. LexA repressor that negatively controls RecA protein synthesis appeared more susceptible to cleavage than did repressor.     

Food Quality Constraints in Daphnia: Interspecific Differences in the Response to the Absence of a Long Chain Polyunsaturated Fatty Acid in the Food Source

The effect of the long chain polyunsaturated fatty acid (PUFA) eicosapentaenoic acid (EPA, 20:53) on food quality for Daphnia galeata, Daphnia hyalina and a D. galeata×hyalina hybrid was examined. Somatic growth rates of all three species were determined when growing on EPA-free Scenedesmus obliquus and on S. obliquus which had been supplemented with free EPA prior to the growth experiments. Growth rates on S. obliquus were substantially higher in D. galeata(0.45day^–1) than in D. hyalina(0.27day^–1) and D. galeata×hyalina(0.31day^–1). Supplementary EPA increased growth of D. galeata and D. hyalina, but not of the hybrid. Hence within the D. galeata/hyalina complex species differ in their ability to cope with an EPA-free diet. Analysis of fatty acids revealed that tissue concentrations of 18:33, 18:43, 20:33 and 20:43 were higher in D. galeata than in D. hyalina which indicated higher rates of assimilation and biosynthesis of PUFAs in D. galeata. This was contrasted by lower tissue concentrations of 20:53 D. galeata than in D. hyalina which suggests that 20:53 is metabolised with growth. In the D. galeata×hyalina hybrid high PUFA assimilation and biosynthesis were associated with low growth rates which explains the finding that tissue concentrations of 20:53 were highest and that growth was not constrained by the availability of 20:53.     

A new metabolic pathway from n-dodecane to α, ω-dodecanedioic acid in a mutant of Candida tropicalis

Summary The metabolic formation of ,-dodecanedioic acid via ,-dodecanediol from n-dodecane using a mutant S76 of Candida tropicalis was studied.It was found that resting cells of S76 produce ,-dodecanediol from n-dodecane. This intermediate was identified by different analytical methods. With n-dodecanol as substrate the quantitative changes in the concentrations of ,-dodecanediol as well as other intermediates, e.g. monoacid, -hydroxy acid and ,-dioic acid produced by resting cells of S76 for different periods of time were determined. With ,-dodecanediol as the sole carbon source, quantitative changes of -hydroxy acid and ,-dioic acid produced by S76 were also recorded.The results confirm the existence of a new metabolic pathway via ,-diol in the course of ,-dioic acid formation from n-alkane in the mutant S76 of C. tropicalis.     

Binding Properties of the Galactose-detecting Lectin Pseudomonas aeruginosa Agglutinin (PA-IL) to Skeletal Muscle Fibres. Quantitative Precipitation and Precipitation Inhibition Assays

Pseudomonas aeruginosa agglutinin (PA-IL) staining and the influence of various carbohydrates on lectin binding to muscle sections were investigated quantitatively using a scanning and integrating microspectrophotometre. A strong dose-dependent inhibition of PA-IL staining in the sections was recorded with galabiose (Gal1-4Gal) while lactose (Gal1-4Glc) had no inhibitory effect. The affinity of PA-IL to Gal1 carbohydrates was studied by ELISA using immobilized glycoconjugates in which Gal1 glycans were attached to bovine serum albumin or ceramide. PA-IL exhibited strong binding to both simple glycoconjugates having a single Gal moiety and to di- and trisaccharides with terminal Gal1 at the non-reducing end. In all cross-sectioned muscle fibres incubated with PA-IL, the staining was present as a honeycomb-shaped network through the entire cytoplasm. Further, a dense punctuate staining could be shown in most fibres. A similar staining pattern was noticed after incubation with a monoclonal antibody against ryanodine receptors and with biotinylated ryanodine suggesting that the network could represent the sarcoplasmic reticulum. Further, Western blots of a sarcoplasmic reticulum preparation showed multiple bands after incubation with PA-IL. It may therefore be proposed that glycoconjugates carrying terminal Gal1 show affinity for PA-IL and are located to the sarcoplasmic reticulum.     

Similarities of omega gliadins from<Emphasis Type="Italic"> Triticum urartu</Emphasis> to those encoded on chromosome 1A of hexaploid wheat and evidence for their post-translational processing

The -gliadins encoded on chromosome 1 of the A genome were purified from Triticum aestivum L. (2n=6x=42, AABBDD) cv. Butte86, nullisomic 1D-tetrasomic 1A of cv. Chinese Spring (CS N1DT1A), and the diploid T. urartu (2n=2x=14, AA). Reverse-phase high-performance liquid chromatography combined with sodium dodecyl sulfate-polyacrylamide gel electrophoresis of gliadin extracts from CS nullisomic-tetrasomic (NT) lines confirmed the assignment to chromosome 1A. The purified -gliadins were characterized by mass spectrometry and N-terminal sequencing. The 1A-encoded -gliadins were smaller than 1B- or 1D-encoded -gliadins. The N-terminal amino acid sequences for 1A -gliadin mature peptides were nearly identical to those for the T. urartu -gliadins and were more similar to 1D -gliadin sequences than to sequences for T. monococum -gliadins, barley C-hordeins, or rye -secalins. They diverged greatly from the N-terminal sequences for the 1B -gliadins. The data suggest that T. urartu is the A-genome donor, and that post-translational cleavage by an asparaginyl endoprotease produces those -gliadins with N-terminal sequences beginning with KEL.Communicated by J. Dvorak     

Microbial colonization of seston and free bacteria in an impounded river

A headwater river-reservoir system was studied from March–November, 1982 to determine effects of impoundment on seston quality. We used epifluorescent microscopy to compate and contrast microbial colonization of seston and abundance of free microbes. There was a significant relationship between colonization density and particle size at all sites. Smaller particles were colonized more densely by bacteria than larger particles. Total counts of bacteria (free plus attached) did not differ significantly beween sites. However there were significantly more free bacteria (# ml^–1) in the reservoir and 5 km below the dam than upstream of the impoundment. Density of attached bacteria (# µm^–2) was similar upstream and downstream of the reservoir but slightly higher at lentic sites. Proportionally, attached bacteria were more important upstream (mean 42–45% of total counts) than in the reservoir and downstream (19–31%). We concluded that reservoir seston was of higher quality than riverine seston and major downstream effects included decreases in seston concentration (due to sedimentation) and shifts in proportional abundance of free and attached bacteria. Seston consumers capable of using ultrafine particles (<25 µm), including free bacteria, had higher quality food resources below the dam than in upstream areas.     

Inserted sequence in the mitochondrial 23S ribosomal RNA gene of the yeast Saccharomyces cerevisiae.

Summary The sequence organization of the yeast mit-DNA region carrying the large ribosomal RNA gene and the polar locus was examined. Hybridization studies using rho^- deletion mutants and electron microscopy of the heteroduplexes formed between 23S rRNA and the appropriate restriction fragments, lead to the conclusion that the 23S rRNA¹ gene of the ⁺ strains is split by an insertion sequence of 1,000–1,100 bp. In contrast, no detactable insertion was found in the 23S rRNA gene of the ^- strains. The size and the location of the insert found in the 23S rRNA gene of the ⁺ strains appear to be identical to those of the sequence which had previously been found to characterize the difference (at the locus) between the mitDNA of the wild type strains carrying the ⁺ or ^- alleles (Jacq et al., 1977).     

Fatty acid content in wild type and WZSL mutant of Euglena gracilis

The effects of growth conditions on fatty acid profilewere examined in the photosynthetic wild type and inthe spontaneous non-photosynthetic WZSL mutant of theunicellular flagellate Euglena gracilis. Inthe light, the amount of polyunsaturated fatty acids(PUFAs) is higher in the wild type than in the mutant,independent of the carbon source. Among importantPUFAs, linolenic acid (18:3 3) is present inhigh amount only in wild type cells grown in the lightwith any of the tested carbon sources. The content ofother PUFAs, such as arachidonic acid (20:46), EPA (20:5 3) and DHA (22:63), is not correlated with the presence oflight or chloroplasts.The main effect of the dark in both strains is tolower the content of PUFAs and mono-unsaturated fattyacids and to increase the content of saturated fattyacids with all the carbon sources.     

Plant Uncoupling Mitochondrial Protein Activity in Mitochondria Isolated from Tomatoes at Different Stages of Ripening

In the present study we have observed a higher state of coupling in respiring mitochondriaisolated from green as compared to red tomatoes (Lycopersicon esculentum, Mill.). Greentomato mitochondria produced a membrane potential () high enough to phosphorylate ADP,whereas in red tomato mitochondria, BSA and ATP were required to restore to the levelof that obtained with green tomato mitochondria. This supports the notion that such uncouplingin red tomato mitochondria is mediated by a plant uncoupling mitochondrial protein (PUMP;cf. Vercesi et al., 1995). Nevertheless, mitochondria from both green and red tomatoes exhibitedan ATP-sensitive linoleic acid (LA)-induced decrease providing evidence that PUMP isalso present in green tomatoes. Indeed, proteoliposomes containing reconstituted green or redtomato PUMP showed LA uniport and LA-induced H⁺ transport. It is suggested that the higherconcentration of free fatty acids (PUMP substrates) in red tomatoes could explain the lowercoupling state in mitochondria isolated from these fruits.     

Characteristics of specific125I-ω-conotoxin GVIA binding in rat whole brain

Characteristics of specific¹²⁵I-omega-conotoxin (-CgTX) binding were systematically investigated in crude membranes from rat whole brain. Kd and Bmax Values for the binding were 49.7 pM and 181.5 fmol/mg of protein, respectively. The effects of various types of Ca channel antagonists on the binding were investigated. Dynorphin A (1–13), in particular, specifically inhibited¹²⁵I--CgTX binding, but not that of [³H](+)PN200-110. Spider venom fromPlectreurys tristes did not specifically inhibit specific binding of¹²⁵I--CgTX, because the venom also inhibited the binding of [³H](+)PN200-110 to a similar degree. The amount of specific binding of¹²⁵I--CgTX was less in the cerebellum than that in any other area of whole brain. The cross-linker disuccinimidyl suberate did not label with¹²⁵I--CgTX and its binding sites in rat whole brain, although it did in chick whole brain, which was used as a positive control. These findings suggested that dynorphine A (1–13) was a selective blocker of -CgTX-sensitive Ca channels in crude membranes from rat whole brain and that -CgTX-sensitive Ca channels were mainly present a rat brain except cerebellum.     

Formation ofα,ω-dodecanedioic acid andα,ω-tridecanedioic acid from different substrates by immobilized cells of a mutant ofCandida tropicalis

Summary The metabolic formation of either,-dodecanedioic acid or,-tridecanedioic acid from the individual n-alkane, n-alcohol, n-monoacid and,-diol with corresponding carbon chain length using K-carrageenan entrapped mutants S76 ofCandida tropicalis was studied. The immobilized cells of S76 could also directly produce-hydroxy acid and,-dioic acid from,-diol. With n-alcohol and n-monoacid as substrate, the amount of-hydroxy acid and,-dioic acid produced was also a function of the incubation time.The results demonstrated that in the immobilized cells of S76 the formation of,-dioic acid from n-alcohol can also run both via n-monoacid and via,-diol as well as in the normal cells of S76.     

Purification and characterization of hydroxycinnamoyl-coenzyme A: ω-hydroxypalmitic acid O-hydroxycinnamoyltransferase from tobacco (Nicotiana tabacum L.) cell-suspension cultures

An acyltransferase hydroxycinnamoyl-Coenzyme A: -hydroxypalmitic acid O-hydroxycinnamoyltransferase (HHT; EC 2.3.1.-), which transfers hydroxycinnamic acids from hydroxycinnamoyl-CoA thioesters to several hydroxylated fatty acid derivatives, was characterized from tobacco (Nicotiana tabacum L. cv. Xanthi nc) cell-suspension cultures. It exhibited the same properties as the enzyme previously detected in wound-healing potato tuber discs (Lotfy et al., 1994, Phytochemistry 35: 1419–1424), and especially a marked specificity for -hydroxypalmitic acid and feruloyl-CoA. It was purified 300-fold to near homogeneity from late logarithmic-phase cell suspensions. The apparent molecular mass of the native protein was 55 kDa and its isoelectric point, estimated by electrofocusing, was 4.6. The purified enzyme conjugated ferulic acid to -hydroxypalmitic acid and to 1-tetradecanol, its main lipidic substrates, suggesting that the same enzyme probably synthesizes the different esters of 1-alkanols and of -hydroxy fatty acids which are formed in vitro.Abbreviations ABA abscisic acid - IEF isoelectric focusing - HHT hydroxycinnamoyl-Coenzyme A: -hydroxypalmitic acid O-hydroxycinnamoyltransferase - pI isoelectric point     

ALTERNATIVE PSYCHOTHERAPEUTIC PRACTICE AMONG MIDDLE CLASS AMERICANS: II: SOME CONCEPTUAL AND PRACTICAL COMPARISONS

This article will contextualize ethnographic and clinicalfeatures that distinguish one particular alternativehealing method (Self-Acceptance Training) frommainstreampsychotherapeutic procedures. Factors common to manypsychotherapies are listed and a series of contrasts andcomparisons made by examining definitions of: (1) presentingproblems, (2) inciting events, (3) phasic development, (4)taxonomic classifications, (5) therapeutic interventions,and (6) prognostic formulations. The alternative method oftreatment described in a companion publication(SAT) is used to makesome specific comparisons (Zatzick and Johnson 1997).Baschs (1980) concise recording of a dynamic therapy isborrowed for purposes of a comparative hypothetical treatmentof his patient through a Self-Acceptance Training session.Some directions for future work are suggested.     

Phospholipid Fatty Acid Composition and Heavy Metal Tolerance of Soil Microbial Communities along Two Heavy Metal-Polluted Gradients in Coniferous Forests

The effects of long-term heavy metal deposition on microbial community structure and the level of bacterial community tolerance were studied along two different gradients in Scandinavian coniferous forest soils. One was near the Harjavalta smelter in Finland, and one was at Ronnskar in Sweden. Phospholipid fatty acid (PLFA) analysis revealed a gradual change in soil microbial communities along both pollution gradients, and most of the individual PLFAs changed similarly to metal pollution at both sites. The relative quantities of the PLFAs br18:0, br17:0, i16:0, and i16:1 increased with increasing heavy metal concentration, while those of 20:4 and 18:2(omega)6, which is a predominant PLFA in many fungi, decreased. The fungal part of the microbial biomass was found to be more sensitive to heavy metals. This resulted in a decreased fungal/bacterial biomass ratio along the pollution gradient towards the smelters. The thymidine incorporation technique was used to study the heavy metal tolerance of the bacteria. The bacterial community at the Harjavalta smelter, exposed mainly to Cu deposition, exhibited an increased tolerance to Cu but not to Cd, Ni, and Zn. At the Ronnskar smelter the deposition consisting of a mixture of metals increased the bacterial community tolerance to all tested metals. Both the PLFA pattern and the bacterial community tolerance were affected at lower soil metal concentrations than were bacterial counts and bacterial activities. At Harjavalta the increased Cu tolerance of the bacteria and the change in the PLFA pattern of the microbial community were found at the same soil Cu concentrations. This indicated that the altered PLFA pattern was at least partly due to an altered, more metal-tolerant bacterial community. At Ronnskar, where the PLFA data varied more, a correlation between bacterial community tolerance and an altered PLFA pattern was found up to 10 to 15 km from the smelter. Farther away changes in the PLFA pattern could not be explained by an increased community tolerance to metals.