Nitrogen and phosphorus requirements for the growth and nodulation of Cajanus cajan in Panamanian soils

Chemical analysis and missing element trials with Sorghum vulgare L. showed that three Panamanian soils, representative of three great soil groups, were deficient in both nitrogen (N) and phosphorus (P). When a greenhouse trial was undertaken to test the response of Cajanus cajan to rhizobial inoculation, N and P fertilization in these soils, no response was obtained in either the Río Hato or Los Santos soils. There was a definite response to P and a slight response to inoculation in the Pacora soil, which had the poorest fertility level. N applications depressed nodulation. The lack of response of Cajanus cajan to P in the Río Hato soil was attributed to the high incidence (55 percent) of VA mycorrhizal infection. Inoculation of Cajanus cajan with both Rhizobium and Glomus may be important in low-fertility soils

Failure of the ammonia oxidation process in two pharmaceutical wastewater treatment plants is linked to shifts in the bacterial communities W.

Aims: To investigate whether two different wastewater treatment plants (WWTPs) – treating the same pharmaceutical influent – select for a different bacterial and/or ammonia oxidizing bacterial (AOB) community. Methods and Results: Molecular fingerprinting demonstrated that each WWTP had its own total bacterial and AOB community structure, but Nitrosomonas eutropha and N. europea were dominant in both WWTP A and B. The DNA and RNA analysis of the AOB communities revealed different patterns; so the most abundant species may not necessarily be the most active ones. Nitritation failures, monitored by chemical parameter analysis, were reflected as AOB community shifts and visualized by denaturing gradient gel electrophoresis (DGGE)-based moving window analysis. Conclusions: This research demonstrated the link between functional performance (nitritation parameters) and the presence and activity of a specific microbial ecology (AOB). Clustering and moving window analysis based on DGGE showed to be valuable to monitor community shifts in both WWTPs. Significance and Impact of the Study: This study of specific community shifts together with functional parameter analysis has potential as a tool for relating functional instability (such as operational failures) to specific-bacterial community shifts