Bowman's membrane lenticule tuck-in: A new approach for the management of neurotrophic ulcers.

PURPOSE: To evaluate a new surgical method for managing nonhealing neurotrophic ulcers using a novel technique of tucking-in Bowman's membrane lenticule in the ulcer defect. METHODS: A total of 22 eyes of 22 patients with neurotrophic ulcers of various etiologies and stages were included and underwent a surgical process where a donor Bowman's membrane lenticule was harvested and fashioned according to the lesion and tucked inside the ulcer after making a recess in anterior one-third of stroma all around 360 degrees. The primary outcomes measured were healing (stable epithelialization at 12 months) and best-corrected visual acuity (BCVA) improvement. RESULTS: Twenty-two eyes of 22 patients with neurotrophic ulcers underwent Bowman's membrane lenticule tuck-in procedure. Complete re-epithelialization was achieved in 21 eyes (95.45%). The average healing time was 2.77 ± 0.79 weeks. The mean corneal thickness improved from 267.36 ± 94.56 mm preoperatively to 435.9 ± 47.71 mm at six months postoperatively. The mean BCVA also improved from 0.05 ± 0.07 preoperatively to 0.24 ± 0.24 postoperatively one year. One patient (4.54%) showed recurrence after one month, and the epithelial defect persisted till the end of the study. CONCLUSION: Donor Bowman's membrane lenticule tuck-in for neurotrophic ulcers is a safe and highly effective treatment and requires minimal instruments and expertise.

2-Benzamide Tellurenyl Iodides: Synthesis and Their Catalytic Role in CO2 Mitigation.

Benzamide-derived organochalcogens (chalcogen=S, Se, and Te) have shown promising interest in biological and synthetic chemistry. Ebselen molecule derived from benzamide moiety is the most studied organoselenium. However, its heavier congener organotellurium is under-explored. Here, an efficient copper-catalyzed atom economical synthetic method has been developed to synthesize 2-phenyl-benzamide tellurenyl iodides by inserting a tellurium atom into carbon-iodine bond of 2-iodobenzamides in one pot with 78-95 % yields. Further, the Lewis acidic nature of Te center and Lewis basic nature of nitrogen of the synthesized 2-Iodo-N-(quinolin-8-yl)benzamide tellurenyl iodides enabled them as pre-catalyst for the activation of epoxide with CO2 at 1 atm for the preparation of cyclic carbonates with TOF and TON values of 1447 h-1 and 4343, respectively, under solvent-free conditions. In addition, 2-iodo-N-(quinolin-8-yl)benzamide tellurenyl iodides have also been used as pre-catalyst for activating anilines and CO2 to form a variety of 1,3-diaryl ureas up to 95 % yield. The mechanistic investigation for CO2 mitigation is done by 125 Te NMR and HRMS studies. It seems that the reaction proceeds via formation of catalytically active Te-N heterocycle, an ebtellur intermediate which is isolated and structurally characterized.

Cerebroplacental ratio and aortic isthmus Doppler in early fetal growth restriction.

PURPOSE: To assess the utility of cerebroplacental ratio (CPR) and fetal aortic isthmus (AoI) Doppler in the prediction of perinatal outcome in early fetal growth restriction (FGR). METHODS: A prospective observational cohort study of 70 early FGR cases was conducted through serial Doppler examinations and findings of the last examination were correlated with perinatal outcome. Doppler blood flow measurements of AoI included end diastolic velocity (EDV), peak systolic velocity (PSV), pulsatility index (PI), resistance index (RI), and isthmic flow index (IFI). RESULTS: Significant association of CPR and all Doppler indices of AoI with the overall adverse perinatal outcome was seen. The sensitivity of CPR was moderate (63.64%) but higher than most AoI indices. Most AoI Doppler indices (PI, RI, IFI) had higher specificities (100%). AoI PSV and EDV had higher sensitivities than CPR for the prediction of overall adverse perinatal outcome, with AoI PSV having the highest sensitivity (100%). CONCLUSION: CPR shows significant association and moderate sensitivity for prediction of overall adverse perinatal outcome in early FGR; hence recommended in all cases of early FGR. AoI Doppler also appears to have a role in assessment and decision making in FGR in view of high sensitivity and high specificity of AoI indices in the prediction of perinatal outcome. However, larger studies are required to confirm its utility in the management of early FGR.

Arabidopsis SMALL DEFENSE-ASSOCIATED PROTEIN 1 Modulates Pathogen Defense and Tolerance to Oxidative Stress.

Salicylic acid (SA) and reactive oxygen species (ROS) are known to be key modulators of plant defense. However, mechanisms of molecular signal perception and appropriate physiological responses to SA and ROS during biotic or abiotic stress are poorly understood. Here we report characterization of SMALL DEFENSE-ASSOCIATED PROTEIN 1 (SDA1), which modulates defense against bacterial pathogens and tolerance to oxidative stress. sda1 mutants are compromised in defense gene expression, SA accumulation, and defense against bacterial pathogens. External application of SA rescues compromised defense in sda1 mutants. sda1 mutants are also compromised in tolerance to ROS-generating chemicals. Overexpression of SDA1 leads to enhanced resistance against bacterial pathogens and tolerance to oxidative stress. These results suggest that SDA1 regulates plant immunity via the SA-mediated defense pathway and tolerance to oxidative stress. SDA1 encodes a novel small plant-specific protein containing a highly conserved seven amino acid (S/G)WA(D/E)QWD domain at the N-terminus that is critical for SDA1 function in pathogen defense and tolerance to oxidative stress. Taken together, our studies suggest that SDA1 plays a critical role in modulating both biotic and abiotic stresses in Arabidopsis (Arabidopsis thaliana) and appears to be a plant-specific stress responsive protein.

ZnO-Modified g-C3N4: A Potential Photocatalyst for Environmental Application.

Solar energy-driven practices using semiconducting materials is an ideal approach toward wastewater remediation. In order to attain a superior photocatalyst, a composite of g-C3N4 and ZnO (GCN-ZnO) has been prepared by one-step thermal polymerization of urea and zinc carbonate basic dihydrate [ZnNO3]2·[Zn(OH)2]3. The GCN-ZnO0.4 sample showed an evolved morphology, increased surface area (116 m2 g-1), better visible light absorption ability, and reduced band gap in comparison to GCN-pure. The GCN-ZnO0.4 sample also showed enhanced adsorption and photocatalytic activity performance, resulting in an increased reaction rate value up to 3 times that of GCN-pure, which was attributed to the phenomenon of better separation of photogenerated charge carriers resulting because of heterojunction development among interfaces of GCN-pure and ZnO. In addition, the GCN-ZnO0.4 sample showed a decent stability for four cyclic runs and established its potential use for abatement of organic wastewater pollutants in comparison to GCN-pure.

Biogenic mediated Ag/ZnO nanocomposites for photocatalytic and antibacterial activities towards disinfection of water.

The current study reports on investigation of pure ZnO nanoparticles (NPs) and Ag/ZnO nanocomposites (NCs) in which Ag noble metal mixed at different concentration (0.5%, 1.0% and 2.0%) in the presence of Ocimum tenuiflorum (Tulsi) plant seed extract (PSE). The structural, optical, electrical and chemical properties of green synthesized NPs and NCs have been monitored using diffrent analytical techniques such as XRD, SEM, TEM, EDX, UV-Vis, FTIR, EIS and EPR. Further the antimicrobial and dye degradation activity of green synthesized pure ZnO-NPs and 0.5%, 1.0% and 2.0% Ag/ZnO-NCs had been examined. The result showed that synthesized 1.0% Ag/ZnO-NCs possessed a good photocatalytic and antimicrobial activity as compared to pure ZnO-NPs and other prepared Ag/ZnO-NCs. Based on the outcomes of reactive oxygen species (ROS) detection, the improved antimicrobial and dye degradation activities of Ag/ZnO-NCs were attributed due to more ROS formation, as Ag particles on the surface of ZnO are in support of electron transfer, which could improve ROS formation by one-electron reduction of oxygen.

VASCULAR PLANT ONE-ZINC FINGER1 (VOZ1) and VOZ2 Interact with CONSTANS and Promote Photoperiodic Flowering Transition.

In plants, endogenous and environmental signals such as light control the timing of the transition to flowering. Two phytochrome B-interacting transcription factors, VASCULAR PLANT ONE-ZINC FINGER1 (VOZ1) and VOZ2, redundantly promote flowering in Arabidopsis (Arabidopsis thaliana). In the voz1 voz2 mutant, the expression of FLOWERING LOCUS C (FLC) was up-regulated and that of FLOWERING LOCUS T (FT) was down-regulated, which was proposed to be the cause of late flowering in voz1 voz2 However, the detailed mechanism by which the VOZ genes promote flowering is not well understood. Here, we show that neither the reduced FT expression nor the late-flowering phenotype of voz1 voz2 is suppressed in the voz1 voz2 flc triple mutant. Genetic interaction experiments between voz1 voz2 and constans-2 (co-2) mutants reveal that the VOZs and CO work in the same genetic pathway. Using in vitro pull-down, electrophoretic mobility shift, and bimolecular fluorescence complementation assays, we show that VOZ1 and VOZ2 interact with CO. The voz1 voz2 35S::CO:YFP plants show suppression of the early-flowering phenotype induced by CO overexpression, suggesting that CO requires VOZ for the induction of flowering. Determination of the VOZ consensus-binding site followed by genome-wide sequence analysis failed to identify any VOZ-binding sites near known flowering time genes. Together, these results indicate that the VOZ genes regulate flowering primarily through the photoperiod pathway, independent of FLC, and suggest that VOZs modulate CO function to promote flowering.

Loss of Color Pigmentation Is Maintained at High Frequency in a Monkey Flower Population.

Color polymorphisms have long been of evolutionary interest for their diverse roles, including mate choice, predator avoidance, and pollinator attraction. While color variation is often under strong selection, some taxa demonstrate unexpectedly high frequencies of presumed deleterious color forms. Here we show that a genetic variant underlying complete loss of anthocyanin pigmentation has risen to an unexpectedly high frequency of >0.2 in a natural population of the plant Mimulus guttatus. Decreased expression of MYB5 transcription factor is associated with unpigmented morphs. While the allele was found only in heterozygote adults in the wild, suggesting negative selection, experiments were unable to demonstrate a fitness cost for unpigmented plants, suggesting a cryptic selection pressure in the wild. However, life-history differences among morphs suggests that unpigmented individuals benefit from later flowering and clonal growth. Overall, our study highlights the complex interplay of factors maintaining variation in nature, even for genes of major effect.

JMJ27, an Arabidopsis H3K9 histone demethylase, modulates defense against Pseudomonas syringae and flowering time.

Histone methylation is known to dynamically regulate diverse developmental and physiological processes. Histone methyl marks are written by methyltransferases and erased by demethylases, and result in modification of chromatin structure to repress or activate transcription. However, little is known about how histone methylation may regulate defense mechanisms and flowering time in plants. Here we report characterization of JmjC DOMAIN-CONTAINING PROTEIN 27 (JMJ27), an Arabidopsis JHDM2 (JmjC domain-containing histone demethylase 2) family protein, which modulates defense against pathogens and flowering time. JMJ27 is a nuclear protein containing a zinc-finger motif and a catalytic JmjC domain with conserved Fe(II) and α-ketoglutarate binding sites, and displays H3K9me1/2 demethylase activity both in vitro and in vivo. JMJ27 is induced in response to virulent Pseudomonas syringae pathogens and is required for resistance against these pathogens. JMJ27 is a negative modulator of WRKY25 (a repressor of defense) and a positive modulator of several pathogenesis-related (PR) proteins. Additionally, loss of JMJ27 function leads to early flowering. JMJ27 negatively modulates the major flowering regulator CONSTANS (CO) and positively modulates FLOWERING LOCUS C (FLC). Taken together, our results indicate that JMJ27 functions as a histone demethylase to modulate both physiological (defense) and developmental (flowering time) processes in Arabidopsis.

Defining the Metabolic Functions and Roles in Virulence of the rpoN1 and rpoN2 Genes in Ralstonia solanacearum GMI1000.

The alternative sigma factor RpoN is a unique regulator found among bacteria. It controls numerous processes that range from basic metabolism to more complex functions such as motility and nitrogen fixation. Our current understanding of RpoN function is largely derived from studies on prototypical bacteria such as Escherichia coli. Bacillus subtilis and Pseudomonas putida. Although the extent and necessity of RpoN-dependent functions differ radically between these model organisms, each bacterium depends on a single chromosomal rpoN gene to meet the cellular demands of RpoN regulation. The bacterium Ralstonia solanacearum is often recognized for being the causative agent of wilt disease in crops, including banana, peanut and potato. However, this plant pathogen is also one of the few bacterial species whose genome possesses dual rpoN genes. To determine if the rpoN genes in this bacterium are genetically redundant and interchangeable, we constructed and characterized ΔrpoN1, ΔrpoN2 and ΔrpoN1 ΔrpoN2 mutants of R. solanacearum GMI1000. It was found that growth on a small range of metabolites, including dicarboxylates, ethanol, nitrate, ornithine, proline and xanthine, were dependent on only the rpoN1 gene. Furthermore, the rpoN1 gene was required for wilt disease on tomato whereas rpoN2 had no observable role in virulence or metabolism in R. solanacearum GMI1000. Interestingly, plasmid-based expression of rpoN2 did not fully rescue the metabolic deficiencies of the ΔrpoN1 mutants; full recovery was specific to rpoN1. In comparison, only rpoN2 was able to genetically complement a ΔrpoN E. coli mutant. These results demonstrate that the RpoN1 and RpoN2 proteins are not functionally equivalent or interchangeable in R. solanacearum GMI1000.

EXTENSIN18 is required for full male fertility as well as normal vegetative growth in Arabidopsis.

EXTENSINS (EXTs) are a 65-member subfamily of hydroxyproline-rich glycoproteins (HRGPs) of which 20 putatively form crosslinking networks in the cell wall. These 20 classical EXTs are involved at the start of new wall assembly as evidenced by a requirement for EXT3 during cytokinesis, and the ability of some EXTs to polymerize in vitro into dendritic patterns. EXT3 was previously shown to form pulcherosine (three Tyrosines) cross-links. Little direct data exists on the other 19 classical EXTs. Here, we describe the phenotypes of ext18 mutants and rescued progeny as well as associated expression profiles of all 20 classical EXT genes. We found that EXT18 is required for full male fertility, as well as for normal vegetative growth. EXT18 has potential to form crosslinking networks via di-iso-di-tyrosine (four Tyrosines) covalent bonds, and not via pulcherosine due to deficit of lone Tyrosines. This together with ext18 defective pollen grains and pollen tubes, and reduced plant size, suggests that EXT18-type EXTs are important contributors to wall integrity, in pollen and other rapidly extending walls. The data also show that a knockout of EXT18 had a pleiotropic affect on the expression of several EXTs, as did the reintroduction of the native EXT18 gene, thus supporting the thesis that transcription of groups of EXTs are co-regulated and work in different combinations to make distinctive inputs into wall assembly of different cell types. These insights contribute to basic knowledge of cell wall self-assembly in different cell types, and potentially enable biotechnological advances in biomass increase and plant fertility control.