Microbial ATP Concentrations Research Articles

Changes in soil microbial biomass C, ATP and microbial ATP concentrations due to increasing soil Cd levels in Chinese paddy soils growing rice (Oryza sativa)

The mean biomass ATP concentration in aerobic soils is around 10–11 μmol ATP g−1 biomass C, within a fairly narrow range. It is much lower in short-term incubated laboratory waterlogged soils. However, the biomass ATP concentration in waterlogged paddy soils under field conditions remains unknown. This is investigated. Soil microbial biomass C (biomass C), ATP, biomass ATP and heavy metal (Cd, Zn, and Cu) concentrations in soil and rice were measured in a Chinese paddy soil growing rice. Soils and plants were analyzed at day 0, 30, 75 and 90, over the 90 day growing period with inputs of inorganic fertilizer, or biochar and manure singly or in combination. Both biomass C and ATP concentrations increased, range from 14.9–30.5% for microbial biomass C and 115.8–160.1% for ATP, from initial values until the end of the experiment following manure or biochar addition. An important result was that the biomass ATP concentration increased throughout the growth period. There were also significant negative correlations (p < 0.05) between total and available Cd and these three microbial parameters, despite the low levels of Cd. Over the same period, total plant Cd concentrations increased, and soil Cd decreased. This suggests that the rice acted as a bioaccumulator. The microbial biomass was then in a continually decreasingly toxic environment and responded rapidly by increasing its size. These results demonstrate clear differences in microbial energy dynamics between aerobic and anaerobic microbial populations. Both ATP and biomass C are useful bioindicators of the effects of cadmium contamination on microbial processes in waterlogged soil.

Mechanisms for Photoinactivation of Enterococcus faecalis in Seawater

Field studies in fresh and marine waters consistently show diel fluctuations in concentrations of enterococci, indicators of water quality. We investigated sunlight inactivation of Enterococcus faecalis to gain insight into photoinactivation mechanisms and cellular responses to photostress. E. faecalis bacteria were exposed to natural sunlight in clear, filtered seawater under both oxic and anoxic conditions to test the relative importance of oxygen-mediated and non-oxygen-mediated photoinactivation mechanisms. Multiple methods were used to assess changes in bacterial concentration, including cultivation, quantitative PCR (qPCR), propidium monoazide (PMA)-qPCR, LIVE/DEAD staining using propidium iodide (PI), and cellular activity, including ATP concentrations and expression of the superoxide dismutase-encoding gene, sodA. Photoinactivation, based on numbers of cultivable cells, was faster in oxic than in anoxic microcosms exposed to sunlight, suggesting that oxygen-mediated photoinactivation dominated. There was little change in qPCR signal over the course of the experiment, demonstrating that the nucleic acid targets were not damaged to a significant extent. The PMA-qPCR signal was also fairly stable, consistent with the observation that the fraction of PI-permeable cells was constant. Thus, damage to the membrane was minimal. Microbial ATP concentrations decreased in all microcosms, particularly the sunlit oxic microcosms. The increase in relative expression of the sodA gene in the sunlit oxic microcosms suggests that cells were actively responding to oxidative stress. Dark repair was not observed. This research furthers our understanding of photoinactivation mechanisms and the conditions under which diel fluctuations in enterococci can be expected in natural and engineered systems.

Bioluminescent assay of microbial ATP in postmortem tissues for the estimation of postmortem interval

To study the relationship between changes of microbial ATP in four kinds of murine tissues and the postmortem interval (PMI), healthy SD rats were sacrificed and their muscles, livers, spleens and kidneys were sampled at different postmortem intervals. The concentration of microbial ATP was detected using bioluminescent assay and the data was statistically analyzed. The concentration of microbial ATP in muscle increased with PMI time. The peak appeared at the 7th day after death, and at the 10th day, microbial ATP in muscle tissue increased again. In internal organs, the peaks of microbial ATP were observed at the 8th day after death and the level decreased during 8-10 d. The differences in microbial ATP concentration in liver, spleen and kidney were not statistically significant. During day 0 to day 9 after death, the correlation was best between PMI and microbial ATP in muscle. With PMI as the independent variable, the cubic polynomial regression equation was Y=0.02X(3)-0.166X(2)-0.666X+13.412 (R (2)=0.989, P<0.01). In internal organs, the best correlation was found between PMI and microbial ATP during day 0 to day 10. With PMI as the independent variable, the cubic polynomial regression equation was Y=0.016X(3)-0.127X(2)-0.809X+13.324 (R (2)=0.986, P<0.01). There existed high correlations between PMI and microbial ATP concentration in rat tissues. Since only a small amount of tissue was needed for the detection and the sample was not affected by self-decomposition, the method may extend the time range of PMI estimation.

Microbial biomass and heterotrophic production of surface flow mesocosm wetlands treating woodwaste leachate: Responses to hydraulic and organic loading and relations with mass reduction

Microbial degradation is the major mechanism for removal of organic carbon from woodwaste leachate in surface flow constructed wetlands. To explore the relations of microbial biomass and heterotrophic production with hydraulic and organic loading rates as well as mass reduction rates, this study examined microbial ATP concentration and leucine incorporation rate in water, epiphytic biofilm and sediment of four surface flow mesocosm wetlands fed at different hydraulic loading rates during two periods with 10× and 3× diluted woodwaste leachate. The hydraulic loading rates from 13 to 49 mm d −1 had no effects on microbial biomass and heterotrophic production. The organic loading rates between 32 and 396 g COD d −1 m −3 had significant, negative correlations with heterotrophic production rate and microbial biomass of sediment, and positive correlations with heterotrophic production rates of water and epiphytic biofilm. Higher organic loading yields greater substrate availability for planktonic and epiphytic bacteria, and may induce inhibitory effect on sedimentary bacteria. Microbial attachment played an important role in the establishment of epiphytic and sedimentary communities. The reduction rates for chemical oxygen demand (COD), tannin and lignin (T&L), and volatile fatty acids (VFAs) were significantly correlated to the heterotrophic production rates of water, epiphytic biofilm and sediment together.

Effects of influent strength on microorganisms in surface flow mesocosm wetlands

To choose an appropriate dilution ratio to treat woodwaste leachate without inhibition on heterotrophic bacteria, microbial ATP concentration and the rates of heterotrophic leucine incorporation and acetate uptake were compared across surface flow mesocosm wetlands fed with different strengths of influent. Abundances of protozoa and respiring bacteria were investigated in two mesocosm wetlands to elucidate the effects of influent strength on heterotrophic bacteria. The strongest influent or the raw leachate did not show a significant inhibitory effect on leucine incorporation and acetate uptake. Instead, leucine incorporation rates by bacteria in water, epiphytic biofilm and sediment were higher in mesocosm wetlands fed with a stronger influent. There were significantly more respiring planktonic bacteria (451×10 5 mL −1) and fewer nanoflagellates (3.8×10 3 mL −1) in the mesocosm fed with a strong influent, while fewer respiring planktonic bacteria (38.7×10 5 mL −1) and more nanoflagellates (15.4×10 3 mL −1) in the mesocosm fed with a weak influent. The majority of the total microbial ATP was attributed to sedimentary bacteria, of which >96% were inactive. Heterotrophic activity and its distribution among water, epiphytic biofilm and sediment in the mesocosm wetlands were affected by availability of bacterial substrates and grazing pressure of nanoflagellates.

ATP - bioluminescence as a technique to evaluate the microbiological quality of water in food industry

ATP-bioluminescence was used to evaluate the microbiological quality of water samples collected from the water supply, the water treatment system and from a dairy plant, including ammonia-cooling water and industrial water. For industrial water, there was relation between the ATP-bioluminescence technique and microbial count. There were no differences (p&gt;0.05) between water supply and ammonia-cooling water samples for total and free ATP concentrations nor for the microbial counts. Different microbial ATP concentrations were found for these water samples. The results suggested that the physical chemical quality of ammonia cooling water decreased the RLU measurements slightly. It could be concluded that the total ATP concentration was the most effective technique to evaluate the microbiological quality of water used in the food indsutry by ATP-bioluminescence.

Inhibition of potassium transport and growth of mycobacteria exposed to clofazimine and B669 is associated with a calcium-independent increase in microbial phospholipase A2 activity.

Altered phospholipase A2 (PLA2) activity and its relationship to cation (K+, Ca2+) uptake and growth were investigated in mycobacteria exposed to the riminophenazine antimicrobial agents, clofazimine and B669 (0.15-2.5 mg/L). Microbial PLA2 activity was measured using a radiometric thin-layer chromatography procedure, whereas K+ and Ca2+ transport were measured using 86Rb+ or 42K+ and 45Ca2+, respectively. Short-term exposure (15-30 min) of Mycobacterium aurum A+ or the virulent and avirulent isolates of Mycobacterium tuberculosis H37R to the riminophenazines resulted in dose-related enhancement of microbial PLA2 activity, which was associated with inhibition of K+ influx and growth. Uptake of Ca2+ by mycobacteria was unaffected, or minimally affected, by the riminophenazines at concentrations of < or = 0.6 mg/L, whereas higher concentrations resulted in increased uptake of the cation in the setting of decreased microbial ATP concentrations. The results of kinetic studies using a fixed concentration (2.5 mg/L) of B669 demonstrated that riminophenazine-mediated enhancement of PLA2 activity and inhibition of K+ uptake in mycobacteria are rapid and probably related events that precede, by several minutes, any detectable effects on microbial ATP concentrations and uptake of Ca2+. Inclusion of the extracellular and intracellular Ca2+-chelating agents EGTA (0.2-7.2 g/L) and BAPTA/FURA-2 (0.2-9.5 mg/L), individually or in combination, did not prevent the effects of B669 on mycobacterial PLA2 activity or K+ transport, whereas alpha-tocopherol, which neutralizes PLA2 primary hydrolysis products, antagonized the inhibitory effects of the riminophenazines on microbial K+ uptake and growth. These results demonstrate that the antimycobacterial activities of clofazimine and B669 are related to a Ca2+-independent increase in mycobacterial PLA2, leading to interference with microbial K+ transport.

Studies on pH, number of protozoa and microbial ATP concentrations in rumen-incubated nylon bags with different pore sizes

A number of factors affect predictions of rumen degradability of feedingstuffs when using thein saccotechnique (Lindberg, 1983). One factor which exerts a great influence is the bag cloth aperture (Lindberg &amp; Knutson, 1981; Lindberg &amp; Varvikko, 1982). Without doubt part of the difference in degradation between pore sizes can be explained by differences in particulate matter losses (Lindberg &amp; Knutsson, 1981; Lindberg &amp; Varvikko, 1982). It has, however, also been suggested that the differences between pore sizes are due to the combined effect of differences in liquid exchange between the bags and the rumen contents and on the selection of microbes entering the bags (Lindberg &amp; Varvikko, 1982).