CRISPR-Cas9-mediated knockout of CYP79D1 and CYP79D2 in cassava attenuates toxic cyanogen production.

Cassava (Manihot esculenta) is a starchy root crop that supports over a billion people in tropical and subtropical regions of the world. This staple, however, produces the neurotoxin cyanide and requires processing for safe consumption. Excessive consumption of insufficiently processed cassava, in combination with protein-poor diets, can have neurodegenerative impacts. This problem is further exacerbated by drought conditions which increase this toxin in the plant. To reduce cyanide levels in cassava, we used CRISPR-mediated mutagenesis to disrupt the cytochrome P450 genes CYP79D1 and CYP79D2 whose protein products catalyze the first step in cyanogenic glucoside biosynthesis. Knockout of both genes eliminated cyanide in leaves and storage roots of cassava accession 60444; the West African, farmer-preferred cultivar TME 419; and the improved variety TMS 91/02324. Although knockout of CYP79D2 alone resulted in significant reduction of cyanide, mutagenesis of CYP79D1 did not, indicating these paralogs have diverged in their function. The congruence of results across accessions indicates that our approach could readily be extended to other preferred or improved cultivars. This work demonstrates cassava genome editing for enhanced food safety and reduced processing burden, against the backdrop of a changing climate.

Toxin-Triggered Interleukin-1 Receptor Signaling Enables Early-Life Discrimination of Pathogenic versus Commensal Skin Bacteria.

The host must develop tolerance to commensal microbes and protective responses to infectious pathogens, yet the mechanisms enabling a privileged relationship with commensals remain largely unknown. Skin colonization by commensal Staphylococcus epidermidis facilitates immune tolerance preferentially in neonates via induction of antigen-specific regulatory T cells (Tregs). Here, we demonstrate that this tolerance is not indiscriminately extended to all bacteria encountered in this early window. Rather, neonatal colonization by Staphylococcus aureus minimally enriches for antigen-specific Tregs and does not prevent skin inflammation upon later-life exposure. S. aureus α-toxin contributes to this response by stimulating myeloid cell production of IL-1ß, which limits S. aureus-specific Tregs. Loss of α-toxin or the IL-1 receptor increases Treg enrichment, whereas topical application of IL-1ß or α-toxin diminishes tolerogenic responses to S. epidermidis. Thus, the preferential activation of a key alarmin pathway facilitates early discrimination of microbial "foe" from "friend," thereby preventing tolerance to a common skin pathogen.

The use of lipid-lowering therapy for secondary prevention in patients undergoing percutaneous coronary intervention.

BACKGROUND: Recent literature suggests that lipid-lowering therapy may have an early beneficial effect among patients undergoing percutaneous coronary intervention (PCI) because the therapy decreases cardiac mortality, morbidity and possibly restenosis. OBJECTIVE: The primary objective of the present study was to determine the proportion of PCI patients receiving lipid-lowering therapy at a large, tertiary-care referral centre. METHODS: Patients undergoing a first PCI between August 2000 and August 2002 with corresponding inpatient medication information were included in the study. Patient demographics, procedural variables, and lipid-lowering and other evidence-based cardiac medication data were collected. A multiple logistical regression model was constructed to evaluate the factors associated with the use of lipid-lowering therapy. RESULTS: Of the 3254 cases included in the analyses, 52% were elective, 44% were urgent or salvage, and 4% were emergent. The mean patient age was 63 years, and 73% of patients were male. Over 76% of patients were receiving lipid-lowering therapy at the time of PCI. Patient use of other medications was as follows: acetylsalicylic acid in 96%, beta-blocker in 80% and angiotensin-converting enzyme inhibitor in 59%. In the multiple regression analysis, variables significantly associated with lipid-lowering therapy use included hypercholesterolemia, beta-blocker use, angiotensin-converting enzyme inhibitor use, case urgency, prior coronary artery bypass graft surgery, age and sex. CONCLUSION: Lipid-lowering therapy use rates exceeded those previously reported in the literature. Women and patients undergoing elective procedures appear to be treated less often with lipid-lowering therapy. There remains an opportunity to further optimize use in this high-risk cohort at time of PCI.

Anti-Xa monitoring of enoxaparin for acute coronary syndromes in patients with renal disease.

BACKGROUND: There are limited data on dosing of enoxaparin in patients with renal disease due to the routine exclusion of this population in clinical trials. To account for the potentially delayed drug elimination in these patients, we developed guidelines for adjusting enoxaparin dosing based on anti-Xa monitoring. OBJECTIVE: To evaluate anti-Xa level monitoring, resulting from the standards of practice as set out by our hospital's guidelines for enoxaparin dosing in renally impaired patients. METHODS: A total of 72 separate acute coronary syndrome patient admissions were retrospectively reviewed. All patients had anti-Xa levels taken and creatinine clearance values <30 mL/min during enoxaparin therapy. RESULTS: The average trough anti-Xa level at the once- and twice-daily doses was 0.40 and 0.72 IU/mL, respectively. With twice-daily dosing, only 6% of the trough concentrations were in the target range of 0.2-0.3 IU/mL compared with 36% with once-daily dosing. Of the 22 patients who had a change of dosing frequency from twice to once daily, 5% of trough anti-Xa levels were