Since the (111)In labeled DTPA is known to be stable, the instabi

Since the (111)In labeled DTPA is known to be stable, the instability in both cases must be due to some unstable association

of DTPA to the cMORF, presumably unstable association to some endogenous sites in cMORF. Based on this assumption, a postconjugation-prepurification heating step was introduced, and labeling efficiency and stability were again investigated. By introducing the heating step, the side products were dissociated, and after purification and labeling, the NH(2)-cMORF conjugate provided a stable label and high labeling efficiency with no need for postlabeling purification. The biodistribution of this radiolabeled conjugate in normal mice showed significantly lower backgrounds compared with the labeled unstable native cMORF conjugate. learn more In conclusion, the conventional conjugation procedure to attach the p-SCN-Bn-DTPA to NH(2)-cMORF resulted in side product(s) that were responsible for the (111)In label instability. Adding a postconjugation-prepurification heating step dissociated the side products, improved the label stability and lowered tissue backgrounds buy EPZ-6438 in mice. (C) 2011 Elsevier Inc. All rights reserved.”
“Aim:

The goal of this study was to compare the degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by three Rhodococcus strains under anaerobic, microaerophilic

(< 0 center dot 04 mg l-1 dissolved oxygen) and aerobic (dissolved oxygen (DO) maintained at 8 mg l-1) conditions.

Methods and Results:

Three Rhodococcus strains were incubated with no, low and ambient concentrations of oxygen in minimal

media with succinate as the carbon source and RDX as the sole nitrogen source. RDX and RDX metabolite concentrations were measured over time. Under microaerophilic conditions, the bacteria degraded RDX, albeit about 60-fold slower than under fully aerobic conditions. Only the breakdown product, 4-nitro-2,4-diazabutanal (NDAB) accumulated GDC-0449 datasheet to measurable concentrations under microaerophilic conditions. RDX degraded quickly under both aerated and static aerobic conditions (DO allowed to drop below 1 mg l-1) with the accumulation of both NDAB and methylenedinitramine (MEDINA). No RDX degradation was observed under strict anaerobic conditions.

Conclusions:

The Rhodococcus strains did not degrade RDX under strict anaerobic conditions, while slow degradation was observed under microaerophilic conditions. The RDX metabolite NDAB was detected under both microaerophilic and aerobic conditions, while MEDINA was detected only under aerobic conditions.

Impact and Significance of the Study:

This work confirmed the production of MEDINA under aerobic conditions, which has not been previously associated with aerobic RDX degradation by these organisms. More importantly, it demonstrated that aerobic rhodococci are able to degrade RDX under a broader range of oxygen concentrations than previously reported.

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