Biodegradation of phenoxyacetic acid in soil by Pseudomonas putida PP0301(pR0103), a constitutive degrader of 2, 4–dichlorophenoxyacetate

The efficacy of using genetically engineered microbes (GEMs) to degrade recalcitrant environmental toxicants was demonstrated by the application of Pseudomonas putida PP0301(pR0103) to an Oregon agricultural soil amended with 500 u.g/g of a model xenobiotic, phenoxyacetic acid (PAA). P. putida PP0301(pR0103) is a constitutive degrader of 2, 4–dichlorophenoxyacetate (2, 4–D) and is also active on the non–inducing substrate, PAA. PAA is the parental compound of 2, 4–dichlorophenoxyacetic acid (2, 4–D) and whilst the indigenous soil microbiota degraded 500 ng/g 2, 4–D to less than 10 J–g/g, PAA degradation was insignificant during a 40–day period. No significant degradation of PAA occurred in soil inoculated with the parental strain P. putida PP0301 or the inducible 2, 4–D degrader P. putida PP0301(pR0101). Moreover, co–amendment of soil with 2, 4–D and PAA induced the microbiota to degrade 2, 4–D; PAA was not degraded. P. putida PP0301–(pR0103) mineralized 500–Μg/g PAA to trace levels within 13 days and relieved phytotoxicity of PAA to Raphanus sativus (radish) seeds with 100% germination in the presence of the GEM and 7% germination in its absence. In unamended soil, survival of the plasmid–free parental strain P. putida PP0301 was similar to the survival of the GEM strain P. putida PP0301(pR0103). However, in PAA amended soil, survival of the parent strain was over 10 000–fold lower (< 3 colony forming units per gram of soil) than survival of the GEM strain after 39 days.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75471/1/j.1365-294X.1992.tb00160.x.pd

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

Aim The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. Methods This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. Results Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P &lt; 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. Conclusion One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease