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The aim of this study was to investigate the potential of indigenous arsenic-tolerant bacteria to enhance arsenic phytoremediation by the autochthonous pseudometallophyte Betula celtiberica The first goal was to perform an initial analysis of the entire rhizosphere and endophytic bacterial communities of the above-named accumulator plant, including the cultivable bacterial species. B. celtiberica 's microbiome was dominated by taxa related to Flavobacteriales , Burkholderiales , and Pseudomonadales , especially the Pseudomonas and Flavobacterium genera. A total of 54 cultivable rhizobacteria and 41 root endophytes, mainly affiliated with the phyla Proteobacteria , Bacteroidetes , Firmicutes , and Actinobacteria , were isolated and characterized with respect to several potentially useful features for metal plant accumulation, such as the ability to promote plant growth, metal chelation, and/or mitigation of heavy-metal stress. Seven bacterial isolates were further selected and tested for in vitro accumulation of arsenic in plants; four of them were finally assayed in field-scale bioaugmentation experiments. The exposure to arsenic in vitro caused an increase in the total nonprotein thiol compound content in roots, suggesting a detoxification mechanism through phytochelatin complexation. In the contaminated field, the siderophore and indole-3-acetic acid producers of the endophytic bacterial consortium enhanced arsenic accumulation in the leaves and roots of Betula celtiberica , whereas the rhizosphere isolate Ensifer adhaerens strain 91R mainly promoted plant growth. Field experimentation showed that additional factors, such as soil arsenic content and pH, influenced arsenic uptake in the plant, attesting to the relevance of field conditions in the success of phytoextraction strategies. IMPORTANCE Microorganisms and plants have developed several ways of dealing with arsenic, allowing them to resist and metabolize this metalloid. These properties form the basis of phytoremediation treatments and the understanding that the interactions of plants with soil bacteria are crucial for the optimization of arsenic uptake. To address this in our work, we initially performed a microbiome analysis of the autochthonous Betula celtiberica plants growing in arsenic-contaminated soils, including endosphere and rhizosphere bacterial communities. We then proceeded to isolate and characterize the cultivable bacteria that were potentially better suited to enhance phytoextraction efficiency. Eventually, we went to the field application stage. Our results corroborated the idea that recovery of pseudometallophyte-associated bacteria adapted to a large historically contaminated site and their use in bioaugmentation technologies are affordable experimental approaches and potentially very useful for implementing effective phytoremediation strategies with plants and their indigenous bacteria., (Copyright © 2017 American Society for Microbiology.)

In order to investigate the changes in water quality and the bacterial community structure in Qingcaosha Reservoir during water storage and supply period, the microorganisms in water body were studied by microbial culture counting and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DEEG) technique. Results showed that the water quality had been improved significantly and the nitrogen and phosphorus concentrations significantly reduced after the Yangtze River water flowed into the reservoir. The number of culturable microorganisms in the influent and the reservoir changed with the seasons, and there were more microorganisms in the influent than these in the reservoir during spring and summer, and fewer in autumn and winter, and the precipitation of suspended microorganisms in the water caused the increase of organic matter content in the sediment. PCR-DGGE results showed that bacterial community structure in the reservoir changed with the seasons, and the microbial community diversity was the highest in summer and the lowest in autumn. The cluster analysis showed that the similarity of microbial community structure of water and sediment samples was 62% , which might be due to the contribution of the precipitation of the suspended microorganisms. The dominant microbial species in water had high similarity with alpha, beta-Proteobacteria, Flavobacterium, Rheinheimera, Prochlorococcus, Synechococcus and Marine metagenome, indicating that Qingcaosha Reservoir faced the risk of algae bloom and seawater intrusion. The results provide the fundamental understanding on reservoir operation and can be used as reference for future studies.

The diel change in abundance and community diversity of the bacterioplankton assemblages within the Pacific Ocean at a fixed location in Monterey Bay, California (USA) were examined with several culture-independent (i.e., nucleic acid staining, fluorescence in situ hybridization {FISH}, and 16S ribosomal RNA gene libraries) approaches over a tidal cycle. FISH analyses revealed the quantitative predominance of bacterial members belonging to the Cytophaga-Flavobacterium cluster as well as two Proteobacteria (α- and γ-) subclasses within the bacterioplankton assemblages, especially during high tide (HT) and outgoing tide (OT) than the other tidal events. While the clone libraries showed that majority of the sequences were similar to the 16S rRNA gene sequences of unknown bacteria (32% to 73%), however, the operational taxonomic units from members of the α-Proteobacteria, Bacteroidetes, Firmicutes, and Cyanobacteria were also well represented during the four tidal events examined. Comparatively, sequence diversity was highest in OT, lowest in low tide, and very similar between HT and incoming tide. The results indicate that the dynamics of bacterial occurrence and diversity appeared to be more pronounced during HT and OT, further indicative of the ecological importance of several environmental variables including temperature, light intensity, and nutrient availability that are also concurrently fluctuating during these tidal events in marine systems.

Three bacteria, Alcaligenes faecalis , Flavobacterium sp., and Providencia vermicola , were isolated from dauer juveniles of Rhabditis blumi . The pathogenic effects of the bacteria against 4th instar larvae of Galleria mellonella were investigated. Providencia vermicola and Flavobacterium sp. showed 100% mortality at 48 h after haemocoelic injection, whereas A. faecalis showed less than 30% mortality. Dauer juveniles showed 100% mortality against G. mellonella larvae, whereas axenic juveniles, which do not harbor associated bacteria, exhibited little mortality. All of the associated bacteria were used as a food source for nematode growth, and nematode yield differed with bacterial species. Among the bacterial species, P. vermicola was most valued for nematode yield, showing the highest yield of 5.2 × 10(4) nematodes/mL in the plate. In bacterial cocultures using two of the three associated bacteria, one kind stimulated the other. The highest total bacterial yield of 12.6 g/L was obtained when the inoculum ratio of P. vermicola to A. faecalis was 10:1. In air-lift bioreactors, the nematode growth rate increased with an increasing level of dissolved oxygen. The maximum nematode yield of 1.75 × 10(5) nematodes/mL was obtained at 192 h with an aeration rate of 6 vvm.

Bacterial community diversity in marine bacterioplankton assemblages were examined in 3 coastal locations along the northeastern Gulf of Mexico (GOM) using 16S rRNA gene libraries and fluorescence in situ hybridization approaches. The majority of the sequences (30%-60%) were similar to the 16S rRNA gene sequences of unknown bacteria; however, the operational taxonomic units from members of the Cyanobacteria, Proteobacteria, and Bacteroidetes were also present at the 3 GOM sites. Overall, sequence diversity was more similar between the Gulf sites of Carrabelle and Ochlockonee than between either of the Gulf sites and Apalachicola Bay. Fluorescence in situ hybridization analyses revealed the quantitative predominance of members of the Alphaproteobacteria subclass and the Cytophaga-Flavobacterium cluster within the bacterioplankton assemblages. In general, the study further reveals the presence of many bacterial taxa that have been previously found to be dominant in coastal marine environments. Differences observed in the representation of the various bacterial phylogenetic groups among the GOM coastal sites could be partly attributed to dynamic variations in several site-specific conditions, including intermittent tidal events, nutrient availability, and anthropogenic influences.

A study was carried out taking low temperature domestic wastewater as target in laboratory, the composition of bacteria in activated sludge was analyzed and the degradation kinetics of organics was investigated. Six preponderant psychrotrophs were selected out, belonging to Zoogloea, Aeromonas, Flavobacterium, Micrococcus, Bacillus and Pseudomonaus, respectively. Results show that TTC-dehydrogenase activity of the psychrotroph is 25.44 mg/(L x h) which is 20.5 times more than that of ordinary activated sludge at 4 degrees C. The efficiency of COD biodegradation by psychrotrophs at low and normal temperature is 80.9% and 73.4%, respectively. Mesophilic bacteria almost lost their activity at low temperature. Kinetic analysis shows that biodegradation of organics by psychrotrophs at low and mesothermal temperature as well as mesophilic bacteria at mesothermal temperature are in accordance with the model of first-order reaction. Psychrotrophs, which assure the removal efficiency of organic pollutants at low and normal temperature, could keep the uniform reaction velocity as the mesophilic bacteria and also adapt wide ecological amplitude of temperature. Efficient psychrotrophs were immobilized on soft polyurethane foams which acted as carriers in the experiment at 4 degrees C, as a result of that, the removal efficiency of COD was increased about 18% higher than that of mobilized ones at low temperature, the biodegradation kinetics of COD by immobilized psychrotrophs also followed the first-order reaction model. With glucose in water as the source of nutriment, the reaction velocity of immobilized bacteria is 2.35 times higher than that of the mobilized ones. By the immobilized psychrotrophs biodegradation of varied nutriment, the effluent could achieve the first-degree B of pollutants discharge standard for municipal wastewater treatment plant.

Cadmium-resistant bacteria were isolated from the farmland soil in Zhangshi Irrigation Area in Shenyang of Northeast China, an area has been polluted by heavy metals, especially cadmium, for more than 40 years. The cadA gene was detected in 4 Bacillus strains and for the first time in one Flavobacterium strain. The high sequence identity (93%-99%) of cadA gene, shared indels in different bacterial species and genera, and the phylogenetic incongruence between 16S rDNA gene tree and cadA gene tree suggested that lateral gene transfer (LGT) occurred among Bacillus and Flavobacterium spp. The LGT of cadA gene might play a vital role in promoting the spread of cadmium-resistant phenotypes throughout soil microbial communities.

Vertically transmitted bacterial symbionts are common in arthropods. However, estimates of their incidence and diversity are based on studies that test for a single bacterial genus and often only include small samples of each host species. Focussing on ladybird beetles, we collected large samples from 21 species and tested them for four different bacterial symbionts. Over half the species were infected, and there were often multiple symbionts in the same population. In most cases, more females than males were infected, suggesting that the symbionts may be sex ratio distorters. Many of these infections would have been missed in previous studies as they only infect a small proportion of the population. Furthermore, 11 out of the 17 symbionts discovered by us were either in the genus Rickettsia or Spiroplasma, which are rarely sampled. Our results suggest that the true incidence and diversity of bacterial symbionts in insects may be far greater than previously thought.

Bacterial diversity was assessed in water samples collected from several uranium mining wastes in Ger many and in the United States by using 16S rDNA and ribosomal intergenic spacer amplification retrievals. The results obtained using the 16S rDNA retrieval showed that the samples collected from the uranium mill tailings of Schlema/Alberoda, Germany, were predominated by Nitrospina-like bacteria, whereas those from the mill tailings of Shiprock, New Mexico, USA, were predominated by gamma-Pseudomonas and Frauteria spp. Additional smaller populations of the Cytophaga-Flavobacterium-Bacteroides group and alpha- and delta-Proteobacteria were identified in the Shiprock samples as well. Proteobacteria and Cytophaga-Flavobacterium-Bacteroides were also found in the third uranium mill tailings studied, Gittersee/Coschütz, Germany, but the groups of the predominant clones were rather small. Most of the clones of the Gittersee/Coschütz samples represented individual sequences, which indicates a high level of bacterial diversity. The samples from the fourth uranium waste studied, Steinsee Deponie B1, Germany, were predominantly occupied by Acinetobacter spp. The ribosomal intergenic spacer amplification retrieval provided results complementary to those obtained by the 16S rDNA analyses. For instance, in the Shiprock samples, an additional predominant bacterial group was identified and affiliated with Nitrosomonas sp., whereas in the Gittersee/Coschütz samples, anammox populations were identified that were not retrieved by the applied 16S rDNA approach.

This study describes the microbial community structure of three sandy sediment stations that differed with respect to median grain size and permeability in the German Bight of the Southern North Sea. The microbial community was investigated using lipid biomarker analyses and fluorescence in situ hybridization. For further characterization we determined the stable carbon isotope composition of the biomarkers. Biomarkers identified belong to different bacterial groups such as members of the Cytophaga-Flavobacterium cluster and sulfate-reducing bacteria (SRB). To support these findings, investigations using different fluorescent in situ hybridization probes were performed, specifically targeting Cytophaga-Flavobacterium, gamma-Proteobacteria and different members of the SRB. Depth profiles of bacterial fatty acid relative abundances revealed elevated subsurface peaks for the fine sediment, whereas at the other sandy sediment stations the concentrations were less variable with depth. Although oxygen penetrates deeper into the coarser and more permeable sediments, the SRB biomarkers are similarly abundant, indicating suboxic to anoxic niches in these environments. We detected SRB in all sediment types as well as in the surface and at greater depth, which suggests that SRB play a more important role in oxygenated marine sediments than previously thought.

Changes in the soil bacterial community of a coniferous forest were analyzed to assess microbial responses to wildfire. Soil samples were collected from three different depths in lightly and severely burned areas, as well as a nearby unburned control area. Direct bacterial counts ranged from 3.3-22.6 x 10(8) cells/(g.soil). In surface soil, direct bacterial counts of unburned soil exhibited a great degree of fluctuation. Those in lightly burned soil changed less, but no significant variation was observed in the severely burned soil. The fluctuations of direct bacterial count were less in the middle and deep soil layers. The structure of the bacterial community was analyzed via the fluorescent in situ hybridization method. The number of bacteria detected with the eubacteria-targeted probe out of the direct bacterial count varied from 30.3 to 84.7%, and these ratios were generally higher in the burned soils than in the unburned control soils. In the surface unburned soil, the ratios of alpha-, beta- and gamma-proteobacteria, Cytophaga-Flavobacterium group, and other eubacteria groups to total eubacteria were 9.9, 10.6, 15.5, 9.0, and 55.0%, respectively, and these ratios were relatively stable. The ratios of alpha-, beta- and gamma-proteobacteria, and Cytophaga-Flavobacterium group to total eubacteria increased immediately after the wildfire, and the other eubacterial proportions decreased in the surface and middle layer soils. By way of contrast, the composition of the 5 groups of eubacteria in the subsurface soil exhibited no significant fluctuations during the entire period. The total bacterial population and bacterial community structure disturbed by wildfire soon began to recover, and original levels seemed to be restored 3 months after the wildfire.

Dense microbial mats and streamers of various colors developed in an alkaline-hot spring water at 48-76 degrees C and ~0.077 mm sulfide in Nakabusa, Japan. The microbial community structures with a thermal gradient were compared by denaturing gradient gel electrophoresis (DGGE) analysis of the PCR-amplified 16S ribosomal RNA gene fragments. The sequence analysis revealed that a predominant cyanobacterial DGGE band phylogenetically related to Synechococcus elongatus was detected only from green mats at 48 degrees C. Four DGGE bands were detected commonly from green mats at 48 degrees C, orange mats at 58 degrees C and brown mats at 60 degrees C. The sequence analysis revealed that these were phylogenetically related to Chloroflexaceae group, Rhodothermus group, a candidate division OP10, and an unclassified bacterium. On the other hand, Aquificae-, Thermodesulfobacteria-, Thermus group-, and Crenarchaeota-like sequences were detected as a predominant component of DGGE profiling from the streamers only at temperatures over 66 degrees C, but no phototrophic bacterial bands were detected. Thus, the microbial community structure above 60 degrees C was drastically different from that at the lower temperatures. After the addition of hydrogen into in vitro gray streamers with in situ spring water, sulfide production markedly occurred in the presence of ambient sulfate at 66 degrees C. This result suggests that in situ sulfide is partly produced by Thermodesulfobacteria-like sulfate-reducing bacteria in the streamers.

The seasonal dynamics of river biofilm communities in two German rivers, the Elbe and one of its tributaries, the Spittelwasser, were investigated for the first time by using fluorescence in situ hybridization and a standardized biofilm sampling procedure. We show the importance of members of the beta subclass of the class Proteobacteria, which formed the largest single group in the massively polluted Spittelwasser at all times. Clear seasonal peaks of abundance were observed for the planctomycetes and the Cytophaga-Flavobacterium cluster.

Rapid and inexpensive sorting of bacterial isolates may be achieved using Fourier transform infrared spectroscopy (FT-IR), a method that has hitherto been applied to identification and classification. The comprehensive characterization of environmental samples requires the isolation of large numbers of isolates using different growth media and growth conditions. In such cases, sorting the isolates is critical before isolates are subjected to more detailed studies. Using FT-IR, isolates are grown under standardized conditions, and 100 strains can be tested within less than 8 h. Chemotaxonomic and molecular characterization of members of clusters emerging from FT-IR analysis either at a level of spectral distance values below 20-30 (analysis of region 600-800 cm(-1), average linkage algorithm) or at spectral heterogeneity values below 75 (regions 1,200-900, 3,000-2,798 and 901-698, scaling to first region, Ward's algorithm) reveals great similarities in fatty acids and 16S rDNA sequences. As judged from riboprinting analyses and fatty acid analyses, FT-IR analysis is able to unravel intraspecific subclustering. The example used in this study of 100 isolates from a mat system, Lake Fryxell, Dry Valleys, Antarctica, selected from a larger number of isolates, picked mainly on the basis of colony pigmentation and form, reveals the utility of the method for identifying the number of putative species quickly. The method described is able to select strains rapidly that represent clusters at the specific and intraspecific level for subsequent characterization.

Dilution cultures are a common technique for measuring the growth of bacterioplankton communities. In this study, the taxonomic composition of marine bacterioplankton dilution cultures was followed in water samples from Plymouth Sound and the English Channel (UK). Bacterial abundances as well as protein and DNA content were closely monitored by flow cytometry. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR)-amplified 16S rDNA fragments and fluorescence in situ hybridization (FISH) were applied directly to the water samples and to cells sorted from the dilution cultures based on their protein and DNA content. As expected, a rapid activation of bacteria occurred. However, molecular techniques showed that the community developed in the dilution culture within 1 day was significantly different from that in the original water samples. Whereas in the original samples, cells detectable by FISH were dominated by members of the Cytophagal Flavobacterium (CF) cluster, in dilution cultures, gamma-proteobacteria accounted for the majority of cells detected, followed by alpha-proteobacteria. An actively growing and an apparently non-growing population with average cellular protein contents of 24 and 4.5 fg respectively, were sorted by flow cytometry. FISH indicated mostly gamma- (64%) and alpha-proteobacteria (33%) in the first active fraction and 78% members of the CF cluster in the second fraction. Sequencing of DGGE bands confirmed the FISH assignments of the latter two groups. The data presented clearly show that even relatively short-term dilution experiments do not measure in situ growth, but rather growth patterns of an enrichment. Furthermore, it was demonstrated that the combination of flow cytometric analysis and sorting combined with FISH and DGGE analysis presented a fairly rapid method of analysing the taxonomic composition of marine bacterioplankton.

Conjugal transfer of a multiresistance plasmid from Pseudomonas fluorescens to halophilic and halotolerant bacteria was studied under in vitro and in situ conditions. Mating conducted in broth as well as on plates yielded a plasmid transfer frequency of as high as 10(-3). Among these two, plate mating facilitated conjugal transfer of plasmid, because the cell-to-cell contact is more in plate mating. When P. fluorescens was incubated in seawater, the organism progressively lost its colony forming activity within 15 days. Microscopic examination revealed the presence of very short rods, indicating that the cells have become viable but nonculturable (VNC). Mating conducted in natural seawater without any added nutrients revealed that the conjugal transfer is influenced by the physical state of the donor and the recipients as well as the availability of nutrients. But a plasmid transfer frequency of 10(-7) was obtained even after the donor cells have become VNC suggesting that the nonculturable state and nutrient deprived condition may not limit plasmid transfer. The results suggest that the terrestrial bacteria entering into the seawaters with antibiotic resistance plasmids may be responsible for the prevalence of resistance genes in the marine environment.

A total of 736 strains were isolated from samples taken from three different saline habitats: solar saltern, saline soils and the sea, near Alicante (Spain). For a further study 60 moderately halophilic nonmotile rods were selected and studied for 57 phenotypic characteristics. The highest proportion of moderately halophilic nonmotile rods were isolated from saline soils and in media with 10 or 20% salts, being very scarce in sea water samples. All were Gram-negative rods and were included in two groups: 33 oxidase positive strains could be assigned to the genus Flavobacterium and 24 oxidase negative strains to the genus Acinetobacter.

The groundwater, polluted with hydrocarbons, showed large cell numbers during one year of examination: 10(3)-10(4) CFU/ml grown on N-agar after 5 days at 20 degrees C, 10(4)-10(5) CFU/ml grown on water-agar after 8 weeks at 20 degrees C and total cell numbers of 10(5)-10(7)/ml. The bacteria, which were isolated from N-agar, were chiefly Pseudomonas, Flavobacterium, Acinetobacter, and other gramnegative species, Arthrobacter and Bacillus as members of grampositive bacteria. Furthermore the following "physiological' groups were found in the groundwater: ammonium-oxidizing bacteria (MPN 10(1)-10(2)/ml), sulfur-oxidizing bacteria (MPN 10(1)-10(4)/ml), nitrate-reducing bacteria (MPN 10(3)-10(6)/ml), denitrifying bacteria (MPN 10(1)-10(4)/ml), spores of aerobe spore-forming bacteria (2-30/ml), spores of anaerobe spore-forming bacteria (0.2-0.4/ml), manganese-oxidizing bacteria (10(3)-10(4) CFU/ml) and Actinomycetes (0.1-1.0 CFU/ml).

Two types of cultures normally expected to be sterile, i.e., urine and blood, were chosen for review at a large university hospital. The bacteria isolated from urine cultures during 1966-70 and from blood cultures from 1966-73 are listed. Two organisms, Flavobacterium meningosepticum and Pseudomonas cepacia, were selected for more detailed study and review. The antibiotic susceptibility patterns for these two organisms are presented.

In a study of a lake having a higher concentration of salts than the Dead Sea, all of the heterotrophic bacteria isolated were aerobes; no strictly anaerobic strains were found. Ninety percent of the strains were euryhalines and ten percent were strict halophiles. The extreme halophiles belonged to the species Halobacterium trapanicum and Halococcus morrhuae.

Water treatment processes such as aeration, gravel filtration, ozonation, activated-carbon filtration and chlorination causes variation in the number of bacteria as well as the development or die off of specific species. The number of bacteria was always reduced to a large extent if ozone or chlorine were applied whereas after filtration process often an increasing number of bacteria could be observed in the effluent. Despite of the differing bacterial counts a reduction of the variety of species was found during all treatment process. Whereas the raw water contained a heterogeneous spectrum of copiotrophic and oligotrophic bacteria the treated water contained mainly slow growing oligotrophic bacteria which didn't express any physiological activities.

Selected surfaces from the Command Module, Lunar Module (ascent and descent stages), Instrument Unit, Saturn S-4B engine, and Spacecraft Lunar Module Adapter comprised the various components of four Apollo spacecraft which were assayed quantitatively and qualitatively for microorganisms. In addition, the first Lunar Roving Vehicle was assayed. Average levels of microbial contamination (10(4) per square foot of surface) on the Command Module, Instrument Unit, and Saturn S-4B engine were relatively consistent among spacecraft. The first postflight sampling of interior surfaces of the Command Module was possible due to elimination of the 21-day back-contamination quarantine period. Results of the pre- and postflight samples revealed increases in the postflight samples of 3 logs/inch(2). A total of 5,862 microbial isolates was identified; 183 and 327 were obtained from the Command Module at preflight and postflight sampling periods, respectively. Although the results showed that the majority of microorganisms isolated were those considered to be indigenous to humans, an increase in organisms associated with soil and dust was noted with each successive Apollo spacecraft.

The group of organisms often labelled as "slow-growing pigmented water bacteria" may include various species of the Xanthomonas, Cytophoga, Pseudomonas, Aeromonas and Flavobacterium genera. Due to their slow growth, this group is usually overlooked in the average clinical laboratory since the pigmented colonies are most easily noted on membrane filter pads or on surface streaked agar plates, but only after 5-15 days of incubation at room temperature. Although present at low levels in free-flowing domestic water supplies (less than 1 per ml), they can be easily isolated by swabbing sink faucets, drinking fountain heads, surgical scrub sink heads and aerators, dental chair spray units, and from the air water interface in humidifiers, nebulizers, water baths, and reservoirs where the water may remain static for weeks. Although not considered primary pathogens, several strains have been implicated in infections in nurseries and among patients in intensive care units. Contamination control in critical research and patient care areas demands scrupulous sanitation practices, regular cleaning and decontamination of all equipment, and the use of bacteria-free water whenever possible.

A total of 51 samples from 32 different kinds of mineral water were examined to investigate their microbial facies in view of a possible relationship with ionic composition. No difference was found between mineral and oligomineral waters. The genera most represented were Pseudomonas, Flavobacterium and Alcaligenes; only rarely could members of these genera be assigned precisely to a defined species, because many strains showed intermediate patterns. The authors suggest widening the microbiological examination of mineral waters and improving ecological and taxonomic knowledge of the autochthonous species in all processing phases in order to evaluate not only their compliance with the law, but also the variations imposed on microflora by different conditions related to container materials, time and temperature of storage.

The investigations are concerned with bacteria which had been isolated from use-surface disinfectant solutions originated from 19 disinfection dosage apparatus of different hospitals and from 8 taps of a centralised disinfection dosage apparatus in an other hospital. The greatest part of the isolated bacteria belonged to the genus Pseudomonas. Beyond it there were yellow-pigmented bacteria like Xanthomonas, Flavobacterium and Micrococcus. After subculture on solid peptone-containing media most of the isolated bacteria turned out to be sensitive to the disinfection solutions in a concentration range, that had been applied in the dosage apparatus. The examination of 6 disinfectants showed, that there were considerable differences in the efficiency to kill the bacteria. Even one preparation pointed out to be absolutely ineffective at applied concentrations.

Bacterial populations increased in juice of healthy tissue of sugarbeet roots stored at 5 C. Average counts showed a sixfold increase after 150 days of storage. Invert sugar levels increased over threefold in "American 4 Hybrid A" and remained fairly constant in "Mono-Hy D-2." The former cultivar also had significantly higher bacterial colony counts than the latter before 90 days of storage. Of 36 isolates identified, 16 were Pseudomonas spp. including P. chlororaphis; 6 Bacillus spp. including B. subtilis; 5 Arthrobacter spp. including A. globiformis; 4 yeasts; 2 Erwinia spp; 2 Flavobacterium spp. including F. aquatile; and Streptomyces longisporus. Isolates of all genera except S. longisporus were able to hydrolyze sucrose in vitro.

Conditions were studied for the coagulation of aggregation-stable Bacillus subtilis, Flavobacterium rigens and Escherichia coli cell dispersions. Their aggregative stability decreased when montmorillonite, a clay mineral, was added to a weakly acid medium or in the presence of Al3+ ions. Bacterial heterocoagulation under the action of montmorillonite can be used as a universal strategy for biomass isolation from aqueous dispersion media.

The microbial populations in chlortetracycline (CTC)-treated (50, 100, 200, and 500 ppm), frozen (-15 C), and irradiated (0.1 Mrad) ocean perch (Sebastodes alutus) were compared. The control sample spoiled at 7 C, primarily because of the growth of Pseudomonas. Irradiation changed this to Achromobacter-dominated spoilage. Freezing or CTC treatment altered the spoilage pattern very little. CTC was particularly effective against ultraviolet fluorescent Pseudomonas species at the higher concentrations. Freezing and CTC were not effective against "coryneforms."