Presence of Erwinia chrysanthemi in two major river systems and their alpine sources in Australia

C other , E.J. & G ilbert , R.L. 1990. Presence of Erwinia chrysanthemi in two major river systems and their alpine sources in Australia. Journal of Applied Bacteriology 69 , 729–738.
Erwinia chrysanthemi was isolated over three summers by filtration, with or without enrichment, of water samples from the headwaters of the Murray and Murrum-bidgee Rivers and from several locations downstream. The bacterium could not be detected in streams rising adjacent to headwater catchments nor could it be detected in freshly voided faeces of native and domestic animals in the vicinity of the Mur-rumbidgee headwaters. Although it survived passage through the intestinal tract of a guinea pig and fowl, it did not persist in either animal. The bacterium survived for at least 211 days at 16C in sterile distilled water. The specific localities from which the bacterium was isolated and the lack of external sources of inoculum indicate that E. chrysanthemi is most likely a constituent of the sessile bacterial population on stream weeds and sediments and is not a contaminant of this alpine environment.     

Verification of ELISA results by immunomagnetic isolation of antigens from extracts and analysis with SDS-PAGE and Western blotting, demonstrated for Erwinia spp. in potatoes

Isolation of antigens on immunomagnetic beads and subsequent analysis with SDS-PAGE and Western blotting (immunomagnetic isolation-Western blotting (IMI-WB)) was used to verify positive ELISA results for Erwinia chrysanthemi and Erw. carotovora subsp. atroseptica in potato peel extracts. Direct analysis of highly contaminated extracts by Western blotting without previous immuno-isolation resulted in background reactions, whereas immunomagnetic isolation resulted in distinct bands of specific antigens. Target cells as well as antigenic cell products were captured in IMI-WB. Band patterns on IMI-WB of cell-free culture filtrates and cell suspensions were highly similar, but the removal of cells lowered the detection level by 10- to 100-fold. Threshold levels of IMI-WB were generally comparable with those of ELISA.
No differences in threshold levels and band patterns were found between a direct format and an indirect format of immuno-isolation.
In IMI-WB, blotting patterns differed between Erw. chrysanthemi and Erw. carotovora subsp. atroseptica. The patterns were identical for 15 Erw. chrysanthemi strains, isolated from potato peel extracts in The Netherlands. However, one of 15 strains of Erw. carotovora subsp. atroseptica from potato peel extracts in The Netherlands gave an aberrant pattern. Target bacteria could be easily distinguished from those of cross-reacting strains on the basis of band patterns.
Potato peel extracts naturally contaminated with Erw. chrysanthemi gave IMI-WB patterns that were similar to pure cultures of the homologous strains.     

Physiological and pathological characteristics of Erwinia chrysanthemi isolates from potato tubers

Nine isolates of Erwinia chrysanthemi from rotting potato tubers were compared with six type or reference strains of this species. Phenotypic properties of the potato isolates closely agreed with those of Erw. chrysanthemi pv. zeae and with the characteristics proposed for Dickey's infrasubspecific subdivision IV (1979) and Samson & Nassan-Agha's biovar 3 (1978), where Zea mays was among the most common host species. Pathogenicity tests on 20 ornamental and agricultural species showed only Cyclamen sp. and Z. mays to be susceptible. In Ouchterlony double diffusion tests, antisera to whole live cells of one potato strain reacted with four of the six pathovars of Erw. chrysanthemi. Tuber isolates did not produce blackleg symptoms in inoculated stems. The rationale of intensive pathogenicity testing is discussed.     

Analysis of cellular fatty acids in Orientia tsutsugamushi as taxonomic markers

Six Orientia strains including 3 prototype strains such as Gilliam, Karp, and Kato, and 3 strains (Boryong, Pajoo, and Yongworl) isolated in Korea, were studied for the profiles of their cellular fatty acids. All tested strains contained octadecenoic acid C (18: 1) omega 9 c(57.3 +/- 3.5%), octadecanoic acid C (18: 0) (15.3 +/- 1.5%), and hexadecanoic acid C (16: 0) (12.7 +/- 1.7%) as major components; however, interestingly, eicosenoic acid C (20: 1) omega 9 c(2.6 +/- 0.6%) was found in all strains except the Yongworl strain. Furthermore none of the strains contained 3-hydroxy fatty acids. The ratios of total saturated fatty acid (SFA) to total unsaturated fatty acid (UFA) were within the range of 0.34 to 0.54. These results showed that the cellular fatty acid profile should provide more reliable information for the identification of these bacteria.     

Catchment-scale biogeography of riverine bacterioplankton

Lotic ecosystems such as rivers and streams are unique in that they represent a continuum of both space and time during the transition from headwaters to the river mouth. As microbes have very different controls over their ecology, distribution and dispersion compared with macrobiota, we wished to explore biogeographical patterns within a river catchment and uncover the major drivers structuring bacterioplankton communities. Water samples collected across the River Thames Basin, UK, covering the transition from headwater tributaries to the lower reaches of the main river channel were characterised using 16S rRNA gene pyrosequencing. This approach revealed an ecological succession in the bacterial community composition along the river continuum, moving from a community dominated by Bacteroidetes in the headwaters to Actinobacteria-dominated downstream. Location of the sampling point in the river network (measured as the cumulative water channel distance upstream) was found to be the most predictive spatial feature; inferring that ecological processes pertaining to temporal community succession are of prime importance in driving the assemblages of riverine bacterioplankton communities. A decrease in bacterial activity rates and an increase in the abundance of low nucleic acid bacteria relative to high nucleic acid bacteria were found to correspond with these downstream changes in community structure, suggesting corresponding functional changes. Our findings show that bacterial communities across the Thames basin exhibit an ecological succession along the river continuum, and that this is primarily driven by water residence time rather than the physico-chemical status of the river.     

Mitochondrial DNA variation suggests river capture as a source of vicariance in Gadopsis bispinosus (Pisces: Gadopsidae)

Gadopsis bispinosus from the Australian Capital Territory (ACT) were genetically similar to a population in north-east Victoria, but highly divergent from another population in central Victoria. Upper tributary populations from the Murray and Murrumbidgee Rivers were similar probably due to river capture.     

长江流域鱼类物种多样性大尺度格局研究

作者以长江流域鱼类编目数据库为基础数据,研究了长江流域鱼类物种多样性的大尺度格局。长江流域内共记录了鱼类378种(亚种),隶属于14目32科144属。其中淡水鱼338种(亚种),以鲤形目为主,达到269种(亚种),洄游鱼类11种,河口鱼类29种;流域内特有种和受威胁物种分别有162种(亚种)和69种(亚种)。根据鱼类分布特点,按水系将长江流域分为19个区域,除了江源区和金沙江中上游外,物种数和G-F多样性指数上游高于中下游,但各区域内差异不大,然而特有种比例从上游到下游随海拔降低而逐渐降低。利用Jaccard物种相似性系数对19个区域进行聚类分析,将整个流域分成三部分:(1)江源区和金沙江中上游,地理上属于青藏高原东南部波状平原部分和横断山区,(2)上游其他流域,地理上属于川西高原、云贵高原、四川盆地及秦巴山区,(3)中下游流域,地理上属于淮阳山地、江南丘陵和长江中下游平原,基本反映了流域内自然地理环境及我国大陆地势三级台阶变化的特点。     

Shape variation in the Australian freshwater mussel Alathyria jacksoni Iredale (Bivalvia,Hyriidae)

Different forms of the hydriid mussel Alathyria jacksoni occur in riverine habitats of the Murray-Darling river system, south-eastern Australia. Electrophoretic data for three enzymes (glucose phosphate isomerase, malate dehydrogenase and malic enzyme) support the assumption that these are morphological variants of one species. Shells from the Murray in South Australia are elongate-oval, with the dorsal margin extended posteriorly as a blade or wing, whereas shells from Victoria and New South Wales have a dorsal arch and a postero-ventral inflection. The variation appears to be associated with water velocity. The arched shells have comparatively large, strong adductor muscles; the posterior adductors are elongate and both anterior and posterior adductors are displaced ventrally. These internal modifications are reflected in changing shell shape as size increases. The changes apparently enhance the mussel's ability to maintain an anchorage in a strong current, but lessen the effectiveness of its valve seal. An incidental observation is that the related species A. condola Iredale, known from the Murrumbidgee and Lachlan rivers, may also occur in the middle reaches of the Murray.     

Microbial oxidation of arsenite and occurrence of arsenite‐oxidizing bacteria in acid mine water from a sulfur‐pyrite mine

The acid mine waters (pH 2.0–2.4) discharged from the Matsuo sul‐fur‐pyrite mine contained high concentrations of dissolved inorganic arsenic (2–13 ppm). Arsenic in the superficial acid mine waters was predominantly in the (V) state (arsenate); however, the element in the water from a deep mine drift was almost in the (III) state (arsenite). Microbial arsenite oxidation occurred in the acid mine waters and along the stream of the river, which was contaminated with a large volume of the mine drift water. Arsenite (500 ppm As)‐resistant bacteria (0–27 colonies/ml) were detected in the water samples and 208 slant cultures were obtained. Arsenite‐oxidizing activities of all the cultures were determined and six strains with strong arsenite‐oxidizing activity were isolated. These bacteria were acidophilic (optimum growth pH, 3—4), gram‐negative, aerobic, and rod‐shaped. They could not oxidize ferrous iron and elemental sulfur as a sole energy source and not derive the energy for chemoautotrophic growth from arsenite oxidation.     

Changes in agricultural intensity and river health along a river continuum

1. The impact of agricultural activities on waterways is a global issue, but the magnitude of the problem is often not clearly recognized by landowners, and land and water management agencies. 2. The Pomahaka River in southern New Zealand represents a typical lowland catchment with a long history of agricultural development. Fifteen sites were sampled along a 119-km stretch of the river. Headwater sites were surrounded by low-intensity sheep farming, with high-intensity pasture and dairying occurring in the mid-reach and lower reaches. 3. Water clarity decreased significantly from about 6 m in the headwaters to less than 2 m in the lower reaches. Benthic sediment levels increased significantly downriver, peaking at 35 mg m^??2 below several tributaries with high-intensity agriculture in their catchments. Periphyton levels were also significantly greater in the lower reaches than the headwaters, and coincided with increased nitrogen (DIN) and phosphorus (SRP) concentrations. 4. Macro-invertebrate species richness did not change significantly throughout the river, but species composition did with Ephemeroptera, and to a lesser extent, Plecoptera and Trichoptera dominating the headwater sites (where there was high water clarity, and low nutrient and periphyton levels). Downriver these assemblages were replaced by molluscs, oligochaetes and chironomids. 5. Canonical correspondence analysis indicated that agricultural intensity and physical conditions associated with agriculture activity (e.g. impacted waters, high turbidity and temperature) were strongly associated with the composition of benthic assemblages at differing reaches down the Pomahaka River. 6. The present results indicate that quantifying agricultural intensity within a catchment, particularly relative livestock densities, may provide a useful tool for identifying threshold levels above which river health declines.     

Bovine Bile Resistance Increases Leuconostoc oenos 44.40 Viability upon Lyophilization

A screening method based on the selection of strains of Leuconostoc oenos 44.40 resistant to bovine bile was developed to obtain strains of the organism more resistant to lyophilization damage. These strains could be used as starter cultures in the malolactic fermentation of wine. The strain resistant to bovine bile was 20% more viable after lyophilization than strains not resistant to bovine bile. This was confirmed in both laboratory-scale production (100 ml) and pilot-scale production (100 liters). Lyophilized cells of strains sensitive and resistant to bovine bile were inoculated into wine, and the malate metabolism by the organism was monitored in the wine. Resistance to bovine bile did not change the malate metabolism characteristic of the organism. A comparison was made of the fatty acid compositions of the two strains. There was a difference in the fatty acid distribution pattern for these two strains. The bovine bile-resistant strain contained more dodecanoic, hexadecanoic, and octadecanoic acid and less tetradecanoic and hexadecanoic acid than did the bovine bile-sensitive strain. Both strains contained high levels of C-19 cyclopropane fatty acid.     

Frequency and diversity of antibiotic production by putative Erwinia herbicola strains

The frequency and diversity of antibiotic production by putative Erwinia herbicola strains were investigated. Of 346 putative Erw. herbicola strains isolated from plants in various regions of France, 42% produced antibiotics on a glycerol-ammonium medium that were inhibitory to Erw. amylovora , the fire-blight pathogen. Of the 90 strains studied in detail that produced antibiotics, 84 produced types of antibiotics that were not toxic to Erw. amylovora (strain CFBP3051) in the presence of different amino acids. On the basis of the amino acids that inhibited the toxicity of the antibiotics to CFBP3051, the 90 strains could be divided into 13 different groups. It is suggested that the effectiveness of an antibiotic in inhibiting Erw. amylovora in vivo may depend on the free amino acid composition of the plant.     

Transmission of F'lac plasmid from Escherichia coli K-12 to bacteria of the genus Erwinia]

The F'lac plasmid was transferred by conjugation from Escherichia coli K-12 W1655 to 21 lac- strains of Erwinia spp. (5.2 . 10(-6) to 6.8 . 10(-2) lac+ exconjugants per donor cell). Erw. herbicola and Erw. chrysanthemi were the better recipients than others. The degree of the stability of lac+ genes in Erwinia exconjugants depends on the strains. Stable exconjugants of Erwinia, which harbored F'lac plasmid, were able to utilize lactose, to transfer lac genes by conjugation to Erwinia spp. and E. coli, and were sensitive to the F-specific phages f1, f2, Qbeta. The F'lac plasmid was eliminated from the exconjugants by the treatment with acridine orange, which indicates that this genetic element is not integrated into the Erwinia chromosome.     

Pseudomonas japonica sp. nov., a novel species that assimilates straight chain alkylphenols

A bacterial strain, WL(T), which was isolated from an activated sludge, was able to degrade alkylphenols. 16S rDNA sequence analysis indicated that strain WL(T) belonged to the genus Pseudomonas (sensu stricto) and formed a monophyletic clade with the type strain of Pseudomonas graminis and other members in the Pseudomonas putida subcluster with sequence similarity values higher than 97%. Genomic relatedness based on DNA-DNA hybridization of strain WL(T) to these strains is 2-41%. Strain WL(T) contained ubiquinone-9 as the main respiratory quinone, and the G+C content of DNA was 66 mol%. The organism contained hexadecanoic acid (16:0), hexadecenoic acid (16:1) and octadecenoic acid (18:1) as major cellular fatty acids. The hydroxy fatty acids detected were 3-hydroxydecanoic acid (3-OH 10:0), 3-hydroxydodecanoic acid (3-OH 12:0) and 2-hydroxydodecanoic acid (2-OH 12:0). These results, as well as physiological and biochemical characteristics clearly indicate that the strain WL(T) represents a new Pseudomonas species, for which the name Pseudomonas japonica is proposed. The type strain is strain WL(T) (=IAM 15071T=TISTR 1526T).     

Relationship of Cellular Fatty Acid Composition to Survival of Lactobacillus bulgaricus in Liquid Nitrogen

Concentrated cultures of Lactobacillus bulgaricus were prepared by resuspending cells grown in semisynthetic media in sterile 10% non-fat milk solids. The concentrated cultures were frozen in liquid nitrogen for 24 h. The cell suspensions exhibited decreased viability after storage, and the amount of death varied among the different strains tested. Storage stability of all strains examined was improved by supplementing the growth medium with sodium oleate. Radioisotopes were used to study the fate of sodium oleate with L. bulgaricus NCS1. [1-(14)C]sodium oleate was incorporated solely into the lipid portion of the cells, including both neutral and polar lipids. The fatty acid composition of L. bulgaricus NCS1, NCS2, NCS3, and NCS4 grown with and without sodium oleate was studied. The major fatty acids of strains NCS1, NCS2, and NCS3 grown without sodium oleate were dodecanoic, tetradecanoic, hexadecanoic, hexadecenoic, and octadecenoic acids. In addition to these, strain NCS4 contained C(19) cyclopropane fatty acid. The major fatty acids of all strains grown with sodium oleate were tetradecanoic, hexadecanoic, hexadecenoic, octadecenoic, and C(19) cyclopropane fatty acids. All strains grown in broth containing sodium oleate contained larger amounts of octadecenoic and C(19) cyclopropane fatty acid, and less saturated fatty acids than when grown without sodium oleate. Statistical analyses indicated that C(19) cyclopropane fatty acid was most closely related to stability of the lactobacilli in liquid nitrogen. A negative regression line that was significant at P < 0.001 was obtained when the cellular content of this fatty acid was plotted against death.     

Polymerase chain reaction for verification of fluorescent colonies of Erwinia chrysanthemi and Pseudomonas putida WCS358 in immunofluorescence colony staining

The potential of polymerase chain reaction (PCR) for verifying the identity of colonies stained by the immunofluorescence colony-staining (IFC) procedure was investigated. Using primers directed against conserved sequences of the pectate lyase-genes coding for isozymes PLa, PLd and PLe of Erwinia chrysanthemi , the authors confirmed the identity of 96% of 20 fluorescent target colonies, punched from IFC-stained samples with pure cultures. In pour plates with mixtures of Erw. chrysanthemi and non-target colonies from potato peel extracts, the identity of 90% of 113 target colonies was confirmed.
Using primers directed against sequences of the ferric-pseudobactin receptor gene pupA of Pseudomonas putida WCS358, the identity of 96% of 22 target colonies was confirmed in IFC-stained samples with pure cultures. In pour plates with mixtures of Ps. putida WCS358 and non-target bacteria from compost extracts, the identity of 59% of 108 fluorescent colonies was confirmed by PCR. It was shown that components from non-target bacteria lowered the threshold level of PCR for Ps. putida WCS358     

Response of wetland plant communities to inundation within floodplain landscapes

Summary Many floodplain wetlands in south‐eastern Australia have become isolated from the main river channel as a consequence of reduced high flows and associated flood events following river regulation. In the Central Murray region of south‐eastern Australia, many temporary wetlands would have received water once every five years or so, with large floods maintaining floodplain connectivity every decade, under natural conditions. Now, the River Murray is highly regulated and many of these wetland areas have not been flooded for periods of up to 30 years. Consequently, these wetlands are becoming degraded and the biodiversity of the area is in decline. From 2001–2003, 21 Black Box depression wetlands in the Central Murray region were each watered once. Plant communities in each wetland were monitored for changes in abundance (assessed as percentage cover) before and during the wetting and drying phases. Wetlands were watered during spring or early summer with the length of inundation ranging from 6 to 19 weeks. After watering, the percentage cover of native plant taxa and native plant functional groups in most wetlands increased. In general, there was a decrease in the percentage number of terrestrial plants present and an increase in the percentage cover of aquatic plants. Introduced species were a minor component. Although these wetlands are all located in the Central Murray region, individual wetlands developed plant communities that contained taxa specific to individual wetlands despite initial similarities. These results indicate that wetland plant biodiversity within the landscape can be promoted and maintained by ensuring there is a diversity of wetlands with varying flood regimes within the landscape.     

Genetic Diversity of Escherichia coli Isolated from Urban Rivers and Beach Water

Repetitive element anchored PCR was used to evaluate the genetic profiles of Escherichia coli isolated from surface water contaminated with urban stormwater, sanitary sewage, and gull feces to determine if strains found in environmental samples reflect the strain composition of E. coli obtained from host sources. Overall, there was less diversity in isolates collected from river and beach sites than with isolates obtained from human and nonhuman sources. Unique strain types comprised 28.8, 29.2, and 15.0% of the isolate data sets recovered from stormwater, river water, and beach water, respectively. In contrast, 50.4% of gull isolates and 41.2% of sewage isolates were unique strain types. River water, which is expected to contain E. coli strains from many diffuse sources of nonpoint source pollution, contained strains most closely associated with other river water isolates that were collected at different sites or on different days. However, river sites impacted by sewage discharge had approximately 20% more strains similar to sewage isolates than did sites impacted by stormwater alone. Beach sites with known gull fecal contamination contained E. coli most similar to other beach isolates rather than gull isolates collected at these same sites, indicating underrepresentation of possible gull strains. These results suggest large numbers of strains are needed to represent contributing host sources within a geographical location. Additionally, environmental survival may influence the composition of strains that can be recovered from contaminated waters. Understanding the ecology of indicator bacteria is important when interpreting fecal pollution assessments and developing source detection methodology.     

Genetic diversity of Escherichia coli isolated from urban rivers and beach water

Repetitive element anchored PCR was used to evaluate the genetic profiles of Escherichia coli isolated from surface water contaminated with urban stormwater, sanitary sewage, and gull feces to determine if strains found in environmental samples reflect the strain composition of E. coli obtained from host sources. Overall, there was less diversity in isolates collected from river and beach sites than with isolates obtained from human and nonhuman sources. Unique strain types comprised 28.8, 29.2, and 15.0% of the isolate data sets recovered from stormwater, river water, and beach water, respectively. In contrast, 50.4% of gull isolates and 41.2% of sewage isolates were unique strain types. River water, which is expected to contain E. coli strains from many diffuse sources of nonpoint source pollution, contained strains most closely associated with other river water isolates that were collected at different sites or on different days. However, river sites impacted by sewage discharge had approximately 20% more strains similar to sewage isolates than did sites impacted by stormwater alone. Beach sites with known gull fecal contamination contained E. coli most similar to other beach isolates rather than gull isolates collected at these same sites, indicating underrepresentation of possible gull strains. These results suggest large numbers of strains are needed to represent contributing host sources within a geographical location. Additionally, environmental survival may influence the composition of strains that can be recovered from contaminated waters. Understanding the ecology of indicator bacteria is important when interpreting fecal pollution assessments and developing source detection methodology.