The results showed that cadmium, nickel and arsenic had a negative influence on the growth of B. Furthermore, it was shown that growth totally recovered when microorganism grown in the presence of metal were inoculated in metal free medium.It is assumed that the metals initially bound to different cell structures, dissociate in the absence of the different metals.
Historically, the only known sites of classical methanogenesis in the surface ocean were the anaerobic microenvironments of faecal matter and the guts of certain fish or plankton in Trichodesmium erythraeum IMS101 that show induction of C–P lyase genes under P starvation and subsequent methane production from MPn.Environmental and laboratory studies have elucidated the forms of dissolved organic matter Pelagibacterales bacteria use, including reduced sulphur compounds, amino acids, one-carbon compounds, organic acids (reviewed in Tripp, strategies for acquiring P appear to vary between Pelagibacterales isolates.For example, compared with the northeast Pacific Ocean isolate, ‘Candidatus Pelagibacter ubique’ strain HTCC1062 (str. HTCC7211 used a broad range of alternate compounds for P nutrition, including P esters (phosphoserine, glucose 6-phosphate and ribose 5-phosphate), phosphonates (2-aminoethylphosphonic acid and MPn) and reduced inorganic P (phosphite) (Fig. In all cases, diauxic growth was observed when str.Gene transcripts encoding phosphonate transport and hydrolysis proteins are upregulated under phosphate limitation, suggesting a genetic basis for the methanogenic phenotype.Strain HTCC7211 can also use 2-aminoethylphosphonate and assorted phosphate esters for phosphorus nutrition.In conclusion, the investigated metals had a bacteriostatic and fungistatic effect on Bacillus mucilaginosus and Aspergillus niger respectively and worked in no way as a bactericide or fungicide.
Both microorganisms exhibited strongly adaptation abilities and presented the potentials to be used in the bioleaching of heavy metal loaded materials, and were good indicator organisms for further research concerning bioleaching approaches.
Metals which exhibited negative effects on the growth of the microorganisms in this first test were further investigated in liquid batch cultures.
Growth curves were prepared using conventional bacterial/fungal growth counting techniques such as plate counting, optical density measurement and dry biomass determination, and were compared with growth curves obtained under normal conditions. These influences were however only characterized by a delayed or reduced growth, and in neither of the batch cultures a total inactivation or dying off of the microorganisms was seen for the concentrations being used (namely 100 ppm metal component).
HTCC7211’s phn I gene, suggesting that Pelagibacterales members mediate a large portion of the C–P lyase activity in the Sargasso Sea.
Using a metric called ‘multiplicity per cell,’ Coleman and Chisholm analysed metagenomic data from the Sargasso Sea (collected in October of 2006) and calculated that ~\n52% of all Pelagibacterales cells contained phn J, a marker gene used to infer the presence of the C–P lyase gene suite production potential of ca. As MPn is part of a complex milieu of dissolved organophosphorus compounds that Pelagibacterales can use (for example, those illustrated in Fig. HTCC7211 cells, previously grown in media with MPn as the sole P source, were used to inoculate sterile, BSA-coated glass serum bottles containing growth media amended with 10 μM MPn as the sole P source. HTCC7211 cells, previously grown in media with P as the sole P source.
1), the actual CH production rates are probably a function of (i) MPn supply relative to the total bioavailable DOP pool accessible to the Pelagibacterales; (ii) the relative efficiency with which MPn is used when multiple substrates are simultaneously available; and (iii) the percent of the Pelagibacterales population that contain C–P lyase genes. 32) were revived from 10% glycerol stocks and propagated in artificial seawater medium for SAR11 (AMS1) production (described below), were grown in acid-washed and autoclaved polycarbonate flasks. Serum bottles (60 ml) were filled with 55 ml culture, leaving a 5-ml headspace, capped with Viton septa, crimped with aluminum seals and incubated horizontally in the conditions described in ‘Cultivation details.’ Cell counts for each treatment were obtained from single bottles used solely for cell counts. The authors declare no competing financial interests.