Browsing by Author "Paras Nath Singh"

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Addition of two new genera—Marcstadlera gen. nov. and Neoclypeosphaerella gen. nov. (Mycosphaerellaceae)—based on polyphasic evidence
(Frontiers Media SA, 2025) Gargee Singh; Soumyadeep Rajwar; Sahana Khatoon; S. Yadav; Pooja Kumari; Raghvendra Singh; Kamalesh Kumar; Smriti Mall; Paras Nath Singh; S. Saran Kumar; Uwe Braun
During a survey of foliicolous fungi in India, two interesting anamorphic hyphomycetous fungal specimens were collected from infected leaves of Calotropis spp. and Mallotus philippensis. Calotropis spp. produce fascicles of conidiophores from stromata, accompanied by secondary superficial hyphae bearing solitary conidiophores. The specimen on Mallotus philippensis resembled Mycovellosiella, characterized by secondary superficial hyphae bearing micronematous to semi-macronematous, mononematous, unbranched, and aseptate conidiophores. A polyphasic approach—including morphological, cultural, and multilocus phylogenetic analyses (LSU-Rpb2-ITS), coupled with genealogical concordance phylogenetic species recognition—identified its relationship with cercosporoid fungi within the family Mycosphaerellaceae. The analysis confirmed that these fungal specimens represent distinct lineages without known morphological or DNA sequence counterparts. Consequently, two new genera are proposed: Marcstadlera and Neoclypeosphaerella, with M. malloti comb. nov. and N. calotropidis comb. nov. as their respective type species. Additionally, Clypeosphaerella calotropidis, Clypeosphaerella quasiparkii, and Pseudocercospora malloti are recognized as new synonyms. Several genera in the Mycosphaerellaceae, including Marcstadlera and Neoclypeosphaerella, are monophyletic. The ultrastructure of the conidiogenous loci and hila differs between these two genera. In Marcstadlera, the loci are cylindrical or peg-like, truncate at the apex, while the conidial base is narrowly obconically truncate. In Neoclypeosphaerella, the loci are slightly protuberant and surrounded by a circular rim-like structure, forming a truncated apex with a centrally positioned small apical depression. The conidial base is obconically truncated and also surrounded by a circular rim-like structure. © © 2025 Singh, Rajwar, Khatoon, Yadav, Kumari, Singh, Kumar, Mall, Singh, Kumar and Braun.
Additions to Ochroconis from India
(Magnolia Press, 2019) Archana Singh; Nikhil Kumar Singh; Paras Nath Singh; Raghvendra Singh; Nawal Kishore Dubey
Ochroconis helicteris, a novel species of the oligotrophic genus Ochroconis (Sympoventuriaceae, Venturiales), has been described and illustrated. Morphologically, this species has characters similar to allied species in the genus Ochroconis, but differs in conidial dimensions and shape. Phylogenetic analyses using nuclear ribosomal DNA gene ITS and protein coding gene BT2 revealed it clustering as monophyletic clade which was separated from known Ochroconis species. New species was isolated from leaf surface of medicinal plant Helicteris isora L. Copyright © 2019 Magnolia Press
Antidiabetic activity of standardized extract of Quassia amara in nicotinamide-streptozotocin-induced diabetic rats
(2011) Gulam Mohammed Husain; Paras Nath Singh; Rakesh Kumar Singh; Vikas Kumar
The aim of the present study was to evaluate the efficacy of a standardized methanol extract of Quassia amara L. (Family: Simaroubaceae) in nicotinamide-streptozotocin-induced diabetic rats. Non insulin dependent diabetes mellitus was induced by streptozotocin in rats pre-treated with nicotinamide. Diabetic rats were treated with oral doses of Quassia amara extract (QaE; 100 and 200 mg/kg) or glibenclamide (10 mg/kg; as standard). QaE and glibenclamide were administered as a suspension in 0.3% carboxy methyl cellulose for 14 days. Control animals received an equal volume of vehicle. Blood samples were collected by retro-orbital puncture on day 14, 1 h after last treatment. Plasma glucose, insulin and lipid parameters (total cholesterol, LDL-C, HDL-C and triglycerides) were measured using commercially available biochemical kits. The oral glucose tolerance test was performed to evaluate the effect of the extract on peripheral glucose utilization in normal rats. Both doses of QaE significantly (p < 0.01) reduced elevated fasting blood glucose levels in diabetic rats. In the oral glucose tolerance test, QaE treatment significantly increased (p < 0.05) the glucose tolerance compared with the vehicle. QaE and glibenclamide, effectively normalized dyslipidemia associated with streptozotocin-induced diabetes. The findings of the present study indicate that Quassia amara extract may be potentially valuable in the treatment of diabetes and associated dyslipidemia. Copyright © 2011 John Wiley & Sons, Ltd.
Chitosan nanoparticles of 5-fluorouracil for ophthalmic delivery: Characterization, in-vitro and in-vivo study
(2011) Ramesh Chand Nagarwal; Paras Nath Singh; Shri Kant; Pralay Maiti; Jayanta Kumar Pandit
The aim of this investigation was to develop 5-fluorouracil (5-FU) loaded chitosan nanoparticles (CH-DNPs) for ophthalmic delivery. CH-DNPs were fabricated by ionotropic gelation mechanism using chitosan (CH) and a polyanion (TPP). The nanoparticles were smooth and spherical, confirmed by scanning electron microscopy (SEM) and atomic force microscope (AFM). CH/TPP mass ratio and TPP significantly changed the particles size morphology and encapsulation efficiency. The nanoparticles size ranged from approximately 114 to 192 nm and had a positive zeta potential (30±4 mV). The encapsulation efficiency, loading capacity and recovery of DNPs were 8.12-34.32%, 3.14-15.24% and 24.22 to 67% respectively. Physical characterization was done by Fourier transform infrared (FT-IR) and X-ray diffraction (XRD). No interaction was observed in between drug and polymer and crystallinity of drug was not changed in drug loaded nanoparticles. In-vitro release study of DNPs showed diffusion controlled release. Bioavailability study of batch CS9 was studied in rabbit eye and compare to 5-FU solution. 5-FU level was significantly higher in aqueous humor of rabbit eye. Ocular tolerance was studied in the eye of New Zealand rabbits and tested formulation was non-irritant with no sign of inflammation. © 2011 Pharmaceutical Society of Japan.
Effect of hydroxypropyl-β-cyclodextrin on the ocular bioavailability of dexamethasone from a pH-induced mucoadhesive hydrogel
(2011) Karthikeyan Kesavan; Shri Kant; Paras Nath Singh; Jayanta Kumar Pandit
Purpose: Dexamethasone (DXN) is an effective anti-inflammatory drug in the treatment of acute and chronic eye disease such as uveitis. It is relatively lipophilic and permeates biological membranes quite easily. However, its low aqueous solubility limits its clinical usefulness. To circumvent this problem Hydroxypropyl-β-cyclodextrin (HP-β-CD) was used as solubilizer and penetration enhancer for DXN. The purpose of this study was to develop HP-β-CD based pH-induced mucoadhesive hydrogel for ophthalmic delivery of DXN to treat uveitis. Materials and methods: The formation of inclusion complex of DXN with HP-β-CD was characterized in solution and solid states by phase solubility, X-ray diffractometry and IR spectrum analyses. To improve ocular retention and sustained action Carbopol 980 NF and sodium carboxymethylcellulose (NaCMC) were added to the formulations as phase transition and mucoadhesive agents, respectively. Results: The HP-β-CD-based hydrogel system enhanced the solubility of DXN and the apparent stability constant (k′) of the DXN-HP-β-CD inclusion complex was found to be 258.62M -1. The optimum concentrations of Carbopol 980NF and NaCMC for the mucoadhesive hydrogel were 0.2% (w/v) and 0.4% (w/v), respectively. This mucoadhesive hydrogel could flow freely under non-physiological condition and showed the character of pseudoplastic fluid under both physiological and non-physiological conditions. In vitro release of DXN from the HP-β-CD complex in simulated tear fluid (STF, pH- 7.4), was influenced significantly by the properties and concentration of Carbopol and NaCMC. In vivo studies in rabbit eye showed a marked improvement in anti-inflammatory activity of mucoadhesive hydrogel-treated eye compared with a marketed solution formulation in a uveitis-induced rabbit eye model. Conclusion: The developed HP-β-CD-based mucoadhesive system is a viable alternative to conventional eye drops of DXN due to its ability to enhance bioavailability through its longer precorneal residence time and ability to sustain the release of the drug. © 2011 Informa Healthcare USA, Inc.
Morphology and Phylogeny of a new species Pseudocercospora rauvolfiicola on medicinal plant Rauvolfia serpentina from Sonebhadra Forest, Uttar Pradesh, India
(Magnolia Press, 2022) Archana Singh; Paras Nath Singh; Nawal Kishore Dubey
A new species of Pseudocercospora is discovered causing foliar disease on the medicinal plant Rauvolfia serpentina (Apocynaceae) from India. The new species is described and illustrated on the morphology of asexual-morphs, growth characters and multigene phylogeny. Morphologically, new species has similar characters with allied species in Pseudocercospora but differs in having catenate and branched conidia. Phylogenetic analysis using combined LSU, ITS, ACT and TEF1α data supports the isolate to be a new species of Pseudocercospora (Capnodiales, Mycosphaerellaceae). Copyright © 2022 Magnolia Press.
Morphology and phylogeny of Pseudocercospora morigena sp. nov. on Morus alba from Vindhya Range, India
(Magnolia Press, 2023) Archana Singh; Paras Nath Singh; Ravindra Nath Kharwar; Nawal Kishore Dubey
Pseudocercospora morigena (Mycosphaerellaceae, Mycosphaerellales) was discovered causing severe foliar leaf spot disease of Morus alba. Identity of the new species is based on morphology, culture characteristics and molecular analyses from three gene regions, internal transcribed spacer regions with intervening 5.8S nrRNA gene (ITS), translation elongation factor 1-alpha gene (TEF1-α) and actin gene (ACT). Morphologically, the present species differs from the allied species reported on the same host genus by the presence of superficial mycelium giving rise to solitary conidiophore, stromata filling stomatal opening and geniculate conidiophores. Copyright © 2023 Magnolia Press.
Morphology and phylogeny of Pseudocercospora trifoliorum sp. nov. (Mycosphaerellaceae) on Grona triflora from India
(Magnolia Press, 2025) Soumyadeep Rajwar; Raghvendra Singh; S. Saran Kumar; Paras Nath Singh; Alok Kumar Singh
Pseudocercospora trifoliorum, a newly discovered foliicolous hyphomycetous fungus on Grona triflora (Fabaceae), is taxonomically described and illustrated. Its phylogeny was determined using LSU, RPB2, and ITS regions to analyze evolutionary relationships. The taxon is compared to closely related Pseudocercospora species through morphological traits and molecular analysis, improving insights into its classification and evolutionary relationships. © 2025 Magnolia Press.
Mucoadhesive chitosan-coated cationic microemulsion of dexamethasone for ocular delivery: In vitro and in vivo evaluation
(2013) Karthikeyan Kesavan; Shri Kant; Paras Nath Singh; Jayanta Kumar Pandit
Purpose: Dexamethasone (DXN) is an effective anti-inflammatory drug in the treatment of acute and chronic eye disease such as uveitis. However, its low aqueous solubility limits its clinical usefulness. The purpose of this study was to investigate the mucoadhesive chitosan-coated cationic microemulsions (CH-MEs) for ophthalmic delivery of DXN to treat uveitis. Materials and methods: The pseudo-ternary phase diagrams were developed and various MEs were prepared using isopropyl myristate as oil, Tween 80 as a surfactant, propylene glycol as a co-surfactant and distilled water. MEs were prepared and coated with chitosan by the dropwise addition of chitosan solution in the ME dispersion. Physicochemical parameters (globule size, zetapotential, drug content, viscosity, refractive index and pH), mucoadhesive properties and the in vitro release of MEs were studied. The in vivo efficacy of prepared formulations and the marketed drug solution were studied by administering them topically to endotoxin-induced uveitis rabbit model. Results: All formulations displayed an average globule size less than 200 nm and a positive surface charge. The developed CH-MEs showed acceptable physico-chemical behavior, good mucoadhesive properties, good stability for three months and exhibited sustained drug release. In vivo studies in rabbit eye showed a marked improvement in the anti-inflammatory activity of mucoadhesive CH-ME-treated eye compared with a marketed suspension formulation in a uveitis-induced rabbit eye model. Conclusion: The developed CH-MEs are a viable alternative to conventional eye drops for its ability to enhance bioavailability through its longer precorneal residence time and its ability to sustain the release of the drug. © 2013 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.
Neokamalomyces indicus gen. nov., sp. nov. (Mycosphaerellaceae)—a Septoria-like genus from India
(Magnolia Press, 2022) Sanjay Yadav; Sanjeet Kumar Verma; Raghvendra Singh; Vinay Kumar Singh; Balmukund Chaurasia; Paras Nath Singh; Shambhu Kumar
A new hyaline coelomycetous fungus discovered on living leaves of Ficus benghalensis (Moraceae) is described and illustrated. Morphologically, it is similar to Septoria or septoria-like genus, but based on cultural characteristics and multigene (LSU-RPB2-ITS) phylogenetic analysis this strain represents an additional lineage in Mycosphaerellaceae. Hence, a new genus and species, Neokamalomyces indicus is proposed. Copyright © 2022 Magnolia Press.
Phylogeny and taxonomy of a novel species of Pseudocercospora from India
(Turkiye Klinikleri, 2021) Archana Singh; Paras Nath Singh; Gopal Nath; Nawal Kishore Dubey
A new species of Pseudocercospora is described causing leaf spot disease on Crotalaria assamica from India. The identity of isolate was based on asexual morphs, cultural characteristics and phylogenetic analyses of partial nuclear ribosomal 28S large subunit and complete internal transcribed spacer rDNA sequence data with high statistical support value. Morphologically this species has characters similar to allied species in genus Pseudocercospora but differs in having catenate and branched conidia. Phylogenetic analysis using LSU and ITS reveals it a new species of Pseudocercospora (Capnodiales, Mycosphaerellaceae). © TÜBITAK.