Publications by authors named "Pradeep K Divakar"

Lichen-forming fungi (LFF) are prolific producers of functionally and structurally diverse secondary metabolites, most of which are taxonomically exclusive and play lineage-specific roles. To date, widely distributed, evolutionarily conserved biosynthetic pathways in LFF are not known. However, this idea stems from polyketide derivatives, since most biochemical research on lichens has concentrated on polyketide synthases (PKSs).

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The genus includes several subcrustose, squamulose, small foliose, and small subfruticose species, primarily in the Southern Hemisphere. Here, we report on the first small foliose species lacking usnic acid in the genus occurring in the Holarctic. The species has been previously known as Nyl.

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Article Synopsis
  • Cryptic species in lichen-forming fungi are prevalent, particularly within the Parmeliaceae family.
  • Researchers focused on asexually reproducing species to clarify their classification and found notable genetic diversity among them.
  • By analyzing genome-wide SNP data, they identified four distinct clades as separate species, including two new species, contributing to a better understanding of their evolutionary relationships.
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Depsides and tridepsides are secondary metabolites found in lichens. In the last 10 years, there has been a growing interest in the pharmacological activity of these compounds. This review aims to discuss the research findings related to the biological effects and mechanisms of action of lichen depsides and tridepsides.

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The lichen species , , and are part of the prominent lichenoflora of the Antarctic territory. In this work, we report the metabolomic identification of ethanolic extracts of these species, their antioxidant and cholinesterase enzyme inhibitory activity, and conduct a molecular docking analysis with typical compounds. Eighteen compounds were identified by UHPLC-ESI-QTOF-MS in , 18 compounds in , and 14 compounds in .

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Oxidative stress is involved in the pathophysiology of many neurodegenerative diseases. Lichens have antioxidant properties attributed to their own secondary metabolites with phenol groups. Very few studies delve into the protective capacity of lichens based on their antioxidant properties and their action mechanism.

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We used molecular data to address species delimitation in a species complex of the parmelioid genus and compare the pharmacological properties of the two clades identified. We used HPLC_DAD_MS chromatography to identify and quantify the secondary substances and used a concatenated data set of three ribosomal markers to infer phylogenetic relationships. Some historical herbarium specimens were also examined.

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The genus s. str. (Parmeliaceae family, Cetrarioid clade) consists of 15 species of mostly erect brown or greenish yellow fruticose or subfoliose thallus.

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Background: Most mammalian cells harbor molecular circadian clocks that synchronize physiological functions with the 24-h day-night cycle. Disruption of circadian rhythms, through genetic or environmental changes, promotes the development of disorders like obesity, cardiovascular diseases, and cancer. At the cellular level, circadian, mitotic, and redox cycles are functionally coupled.

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The worldwide, ecologically relevant lichen-forming genus currently includes 41 accepted species, of which the group (PSULgp) and the group (PSAXgp) have received considerable attention over recent decades; however, phycobiont diversity is poorly known in s. lat. Here, we studied the diversity of microalgae associated with 159 thalli collected from 30 locations, including nine spp.

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Mucormycosis is caused by fungi belonging to the order Mucorales. The term "Black Fungus" has been widely applied to human pathogenic Mucorales in India. They mainly infect the sinuses and brain, lungs, stomach and intestines, and skin.

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Lichens are a symbiotic association between a fungus (mycobiont) and a green algae/- cyanobacterium (photobiont). Lichens are a source of secondary metabolites, most of them being exclusively for these species, among which dibenzofurans are found. Dibenzofurans are a small group (over 35 different identified compounds), being usnic acid the most studied.

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Depsidones are some of the most abundant secondary metabolites produced by lichens. These compounds have aroused great pharmacological interest due to their activities as antioxidants, antimicrobial, and cytotoxic agents. Hence, this paper aims to provide up-to-date knowledge including an overview of the potential biological interest of lichen depsidones.

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Article Synopsis
  • The study focuses on Parmeliaceae, the largest family of lichen-forming fungi, analyzing 250 out of 350 genes to understand its phylogeny across various clades.
  • By employing various analytical methods, the researchers found strong support for the monophyly of two subfamilies and seven major clades within Parmelioideae, as well as notable backbone relationships.
  • The genus Parmotrema was identified as polyphyletic, leading to the proposal of reclassifying some species into a new genus called Crespoa, highlighting the effectiveness of reduced genome-scale data in phylogenetic research.
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Lichen-forming fungi are known to produce a large number of secondary metabolites. Some metabolites are deposited in the cortical layer of the lichen thallus where they exert important ecological functions, such as UV filtering. The fact that closely related lineages of lichen-forming fungi can differ in cortical chemistry suggests that natural product biosynthesis in lichens can evolve independent from phylogenetic constraints.

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Draft genomes of the fungal species , and are presented. is an important lichen forming fungus and is an ambrosia beetle symbiont. and are agriculturally relevant plant pathogens that cause leaf-spots in brassicaceous vegetables and cucurbits respectively.

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Draft genome sequences of five species [including , , , and ], , and are presented. Species of are the causal agents of Eucalyptus leaf blight disease, threatening the growth and sustainability of plantations in China. is the causal agent of stem canker in native and exotic in South Africa.

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Taxonomic identifications in some groups of lichen-forming fungi have been challenge largely due to the scarcity of taxonomically relevant features and limitations of morphological and chemical characters traditionally used to distinguish closely related taxa. Delineating species boundaries in closely related species or species complexes often requires a range of multisource data sets and comprehensive analytical methods. Here we aim to examine species boundaries in a group of saxicolous lichen forming fungi, the Aspiciliella intermutans complex (Megasporaceae), widespread mainly in the Mediterranean.

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Neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease are multifactorial disorders which are increasing in incidence and prevalence over the world without existing effective therapies. The search for new multitarget compounds is the latter therapeutic strategy to address these pathological conditions. Lichens have an important and unknown therapeutic value attributed to their unique secondary metabolites.

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Fungal reproduction is regulated by the mating-type (MAT1) locus, which typically comprises two idiomorphic genes. The presence of one or both allelic variants at the locus determines the reproductive strategy in fungi-homothallism versus heterothallism. It has been hypothesized that self-fertility via homothallism is widespread in lichen-forming fungi.

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Multilocus phylogenetic studies revealed a high level of cryptic diversity within the lichen-forming fungal genus (Protoparmelioideae, Parmeliaceae). Coalescent-based species delimitation suggested that most of the cryptic molecular lineages warranted recognition as separate species. Here we study the morphology and chemistry of these taxa and formally describe eight new species based on phenotypical and molecular characters.

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Article Synopsis
  • Two proposals have been put forward to allow DNA sequences to be used as types for naming certain fungi, which could fundamentally alter the definition of nomenclatural types and lead to various issues in scientific reproducibility and nomenclatural instability.
  • The authors argue against these proposals, suggesting that they would not effectively address the challenges of naming taxa based solely on DNA and propose instead that formulas for naming candidate taxa could be a better solution without changing existing nomenclature rules.
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An understanding of how biotic interactions shape species' distributions is central to predicting host-symbiont responses under climate change. Switches to locally adapted algae have been proposed to be an adaptive strategy of lichen-forming fungi to cope with environmental change. However, it is unclear how lichen photobionts respond to environmental gradients, and whether they play a role in determining the fungal host's upper and lower elevational limits.

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Pertusarialean lichens include more than 300 species belonging to several independent phylogenetic lineages. Only some of these phylogenetic clades have been comprehensively sampled for molecular data, and formally described as genera. Here we present a taxonomic treatment of a group of pertusarialean lichens formerly known as "Pertusaria amara-group", "Monomurata-group", or "Variolaria-group", which includes widespread and well-known taxa such as P.

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