The FaFlbA mutant of Fusarium asiaticum is significantly increased in nivalenol production.

AIMS: Cereals contaminated with type B trichothecene nivalenol (NIV) and its acetylated derivative 4-acetyl-nivalenol (4-AcNIV) are a global mycotoxicological problem threatening the health of humans and livestock. Toxicological studies, quantitative determinations and screening for biodegrading micro-organisms require massive amounts of pure toxins. However, the low yield from fungal cultures and high prices of NIV and 4-AcNIV limit research progress in these areas. This work aimed to select Fusarium asiaticum mutant strains with enhanced production of NIV and 4-AcNIV. METHODS AND RESULTS: A total of 62 NIV-producing F. asiaticum strains were isolated and compared regarding their ability to produce NIV. Strain RR108 had the highest yield of NIV among 62 field isolates surveyed and was then genetically modified for higher production. Targeted deletion of the FaFlbA gene, encoding a regulator of G protein signalling protein, resulted in a significant increase in NIV and 4-AcNIV production in the FaFlbA deletion mutant ΔFaFlbA. The expression of three TRI genes involved in the trichothecene biosynthetic pathway was upregulated in ΔFaFlbA. ΔFaFlbA produced the highest amount of NIV and 4-AcNIV when cultured in brown long-grain rice for 21 days, and the yields were 2.07 and 2.84 g kg-1 , respectively. The mutant showed reduced fitness, including reduced conidiation, loss of perithecial development and decreased virulence on wheat heads, which makes it biologically safe for large-scale preparation and purification of NIV and 4-AcNIV. CONCLUSIONS: The F. asiaticum mutant strain ΔFaFlbA presented improved production of NIV and 4-AcNIV with reduced fitness and virulence in plants. SIGNIFICANCE AND IMPACT OF THE STUDY: Targeted deletion of the FaFlbA gene resulted in increased NIV and 4-AcNIV production. Our results provide a practical approach using genetic modification for large-scale mycotoxin production.

Nanozyme-strip based on MnO2 nanosheets as a catalytic label for multi-scale detection of aflatoxin B1 with an ultrabroad working range.

Lateral flow immunoassay (LFIA) is the most effective real-time detection method for aflatoxin B1 (AFB1). Here, we constructed a nanozyme-strip based on MnO2 nanosheets (MnO2 NSs) as a catalytic label for detection of AFB1. By taking advantage of the MnO2-TMB catalytic amplified system, the new test achieves rapid detection with high sensitivity and ultrawide range. The limit of detection of the assay was 15 pg mL-1, which was over 100-fold lower than the maximum limit set by the European Union (EU) of AFB1 in foods. In addition, the strip test could offer 7 dynamic detection ranges, spanning 4 orders of magnitude, which could cater to the varieties of limits on AFB1 residues in foods and feeds set by different countries. The estimated recoveries were in the range of 85.67%-106.38% with coefficients of variations (CVs) less than 9.68%. Overall, the developed approach is a rapid, reliable, sensitive and widely available tool for on-site detection of AFB1.

Conductive keratoplasty to correct residual hyperopia after cataract surgery.

PURPOSE: To evaluate the efficacy, predictability, safety, and stability of conductive keratoplasty (CK) for correcting residual hyperopia after cataract surgery with intraocular lens implantation. SETTING: Vissum-Instituto Oftalmologico de Alicante, Alicante, and Vissum-Instituto de Albacete, Albacete, Spain. METHODS: Sixteen eyes of 16 patients had CK for the correction of residual hyperopia after cataract surgery. The CK was performed with the CK View Point Refractec (RCS-200, Refractec, Inc.). The follow-up was 12 months. RESULTS: One year after CK, 10 eyes (62.5%) achieved an uncorrected visual acuity (UCVA) of 0.50 or better. The mean UCVA was 0.50 +/- 0.21 (SD), and the mean best spectacle-corrected visual acuity (BSCVA) was 0.68 +/- 0.24. One eye lost 1 line of BSCVA, and none lost 2 or more lines. The mean spherical equivalent refraction was +0.39 +/- 0.84 D 1 year after CK. No vision-threatening complications occurred. CONCLUSIONS: One-year data show that CK for the correction of low to moderate hyperopia after cataract surgery was safe, stable, relatively predictable, and efficient. No complications occurred when CK was performed after phacoemulsification.

Outcomes of microincision cataract surgery versus coaxial phacoemulsification.

PURPOSE: To compare outcomes of microincision cataract surgery (MICS) with coaxial phacoemulsification. DESIGN: Prospective randomized consecutive case series. PARTICIPANTS: One hundred eyes of 50 patients with nuclear or corticonuclear cataract (grades 2+ to 4) with Lens Opacities Classification System III. METHODS: One hundred eyes (50 patients) were randomly operated through clear corneal incisions using 2 techniques: coaxial phacoemulsification (50 eyes) and microincision cataract surgery (50 eyes). MAIN OUTCOME MEASURES: Mean phacoemulsification time, total phacoemulsification percent, effective phacoemulsification time (EPT) (calculated by multiplying total phacoemulsification time in seconds by the average power percent used), intraoperative total balanced salt solution (BSS) volume, visual outcome, vectorial astigmatic changes, corneal thickness, endothelial cell count, and anterior chamber flare and cells preoperatively and at 1 day, 1 month, and 3 months. RESULTS: Statistically significant differences were found between MICS and coaxial phacoemulsification regarding mean incision size, mean total phacoemulsification percent, and EPT. There were no significant differences between the techniques regarding the mean percent of endothelial cell loss, anterior chamber cell count and flare, mean phacoemulsification time, pachymetric measures or total BSS volume utilized, or visual outcome. The vectorial astigmatic changes in the MICS group showed a change of < or =0.25 diopters (D) in 35% of the eyes, 0.25 to 0.5 D in 50% of the eyes, and 0.5 to 1.0 D in 15% of the eyes. These changes were induced by the surgery. Vectorial astigmatic changes of >1 D were not observed. In the coaxial phacoemulsification group, vectorial astigmatic changes of <0.25 D were not observed either. Changes of 0.25 to 0.5 D were seen in 20% of the eyes, and changes of 0.5 to 1.0 D were seen in 30%. Fifty percent of the eyes showed changes of >1.0 D. Mean vectorial astigmatic changes were 0.36+/-0.23 D in the MICS group and 1.2+/-0.74 D in the coaxial phacoemulsification group (P<0.001). CONCLUSIONS: Microincision cataract surgery significantly lowered mean phacoemulsification time, mean total phacoemulsification percent, mean EPT, and surgically induced astigmatism when compared with coaxial phacoemulsification.

Conductive keratoplasty for the correction of residual hyperopia after LASIK.

PURPOSE: To report the 6-month results concerning efficacy, safety, predictability, and stability of conductive keratoplasty for the correction of residual hyperopia after corneal refractive surgery. METHODS: A total of 35 eyes (26 patients) with residual hyperopia after corneal refractive surgery ranging between +1.00 to +4.75 diopters (D) of spherical equivalent refraction were enrolled in the study and underwent conductive keratoplasty following a modified nomogram. RESULTS: Variables and data were available for all eyes at 6 months postoperatively. A total of 24 (69%) eyes had uncorrected visual acuity (UCVA) of > or = 20/40, and 10 (29%) eyes had UCVA of 20/20. Manifest refractive spherical equivalent was within +/- 0.50 D in 17 (49%) eyes and within +/- 1.00 D in 25 (71%) eyes in cases of previous hyperopic LASIK; the optical zone was significantly increased. CONCLUSIONS: Using a modified nomogram, conductive keratoplasty for correction of residual hyperopia was effective, but predictability was not satisfactory and safety needs to be established.

Corneal modeling of keratoconus by conductive keratoplasty.

We evaluated the effect of conductive keratoplasty (CK) applications for corneal modeling to treat keratoconus or post-laser in situ keratomileusis (LASIK) corneal ectasia in 3 patients. Treating keratoconus with CK applications resulted in more regular topography with visual improvement.