Corneal manifestations and treatment among patients with COVID-19-associated rhino-orbito-cerebral mucormycosis.

Purpose: TO report the corneal manifestations in patients with COVID-19-associated rhino-orbito-cerebral mucormycosis (ROCM). Methods: This study was a retrospective, observational, and record-based analysis of patients of ROCM with corneal involvement. Results: A total of 220 patients were diagnosed with ROCM over a period of 3 months. Thirty-two patients had developed corneal manifestations. The mean age at diagnosis was 52.84 ± 12.8 years. The associated risk factors were systemic mucormycosis, uncontrolled diabetes, recent COVID-19 infection, and injudicious use of systemic steroids. Twenty-nine patients were known diabetics, 32 had recent COVID-19 infection, and 13 gave a history of injudicious use of steroids. The right eye (RE) was affected in nine patients, the left eye (LE) in 20 patients, and both eyes in three patients. Nine patients had a round-oval corneal ulcer. One patient each had a perforated corneal ulcer with uveal prolapse, sealed perforated corneal ulcer, spontaneously healed limbal perforation, diffuse corneal haze with hyphemia, panophthalmitis, diffuse corneal stromal abscess, limbal ischemia, anterior uveitis with posterior synechiae, inferior corneal facet, and filamentary keratitis. Three patients each had a corneal melt and inferior conjunctival xerosis with chemosis. Orbital exenteration was performed in six patients. Five patients with corneal ulcers healed. Topical eye drops of amphotericin (0.5 mg/ml) cycloplegic, antiglaucoma medications, and lubricant eye drops were started along with systemic antifungals. Conclusion: Central corneal ulcer was the most common manifestation of mucormycosis. A concentration as low as 0.5 mg/ml of amphotericin eye drops was effective in the treatment.

Light acts as a stressor and influences abiotic and biotic stress responses in plants.

Light is important for plants as an energy source and a developmental signal, but it can also cause stress to plants and modulates responses to stress. Excess and fluctuating light result in photoinhibition and reactive oxygen species (ROS) accumulation around photosystems II and I, respectively. Ultraviolet light causes photodamage to DNA and a prolongation of the light period initiates the photoperiod stress syndrome. Changes in light quality and quantity, as well as in light duration are also key factors impacting the outcome of diverse abiotic and biotic stresses. Short day or shady environments enhance thermotolerance and increase cold acclimation. Similarly, shade conditions improve drought stress tolerance in plants. Additionally, the light environment affects the plants' responses to biotic intruders, such as pathogens or insect herbivores, often reducing growth-defence trade-offs. Understanding how plants use light information to modulate stress responses will support breeding strategies to enhance crop stress resilience. This review summarizes the effect of light as a stressor and the impact of the light environment on abiotic and biotic stress responses. There is a special focus on the role of the different light receptors and the crosstalk between light signalling and stress response pathways.

Role of chromatin modification and remodeling in stem cell regulation and meristem maintenance in Arabidopsis.

In higher plants, pluripotent stem cells reside in the specialized microenvironment called stem cell niches (SCNs) harbored at the shoot apical meristem (SAM) and root apical meristem (RAM), which give rise to the aerial and underground parts of a plant, respectively. The model plant Arabidopsis thaliana (Arabidopsis) has been extensively studied to decipher the intricate regulatory mechanisms involving some key transcriptions factors and phytohormones that play pivotal roles in stem cell homeostasis, meristem maintenance, and organ formation. However, there is increasing evidence to show the epigenetic regulation of the chromatin architecture, gene expression exerting an influence on an innate balance between the self-renewal of stem cells, and differentiation of the progeny cells to a specific tissue type or organ. Post-translational histone modifications, ATP-dependent chromatin remodeling, and chromatin assembly/disassembly are some of the key features involved in the modulation of chromatin architecture. Here, we discuss the major epigenetic regulators and illustrate their roles in the regulation of stem cell activity, meristem maintenance, and related organ patterning in Arabidopsis.