Two novel species of Russula (Russulaceae, Russulales), namely Russula indosenecis A.Ghosh, D.Chakr., K.Das & Buyck sp. nov. and R. pseudosenecis A.Ghosh, D.Chakr., K.Das & Buyck sp. nov. belonging ...to sect. Ingratae subg. Heterophyllidiae are proposed herein based on their morphological features and nrITS-based phylogenetic inferences. Both species belong to the Asian ʻR. punctipes-senecisʼ complex of sect. Ingratae. The acrid R. indosenecis was collected from subalpine forests associated with Abies densa, whereas the mild R. pseudosenecis associates with tropical forests dominated by Shorea robusta. Both species are distinct from the other species of this species complex in nrITS sequence data and from all other known species in subg. Heterophyllidiae in the strong amyloidity of their suprahilar spot.
Ion channel complexes promote action potential initiation at the mammalian axon initial segment (AIS), and modulation of AIS size by recruitment or loss of proteins can influence neuron excitability. ...Although endocytosis contributes to AIS turnover, how membrane proteins traffic to this proximal axonal domain is incompletely understood. Neurofascin186 (Nfasc186) has an essential role in stabilising the AIS complex to the proximal axon, and the AIS channel protein Kv7.3 regulates neuron excitability. Therefore, we have studied how these proteins reach the AIS. Vesicles transport Nfasc186 to the soma and axon terminal where they fuse with the neuronal plasma membrane. Nfasc186 is highly mobile after insertion in the axonal membrane and diffuses bidirectionally until immobilised at the AIS through its interaction with AnkyrinG. Kv7.3 is similarly recruited to the AIS. This study reveals how key proteins are delivered to the AIS and thereby how they may contribute to its functional plasticity.
Glia are of vital importance for all complex nervous system. One of the many functions of glia is to insulate and provide trophic and metabolic support to axons. Here, using glial-specific RNAi ...knockdown in Drosophila, we silenced 6930 conserved genes in adult flies to identify essential genes and pathways. Among our screening hits, metabolic processes were highly represented, and genes involved in carbohydrate and lipid metabolic pathways appeared to be essential in glia. One critical pathway identified was de novo ceramide synthesis. Glial knockdown of lace, a subunit of the serine palmitoyltransferase associated with hereditary sensory and autonomic neuropathies in humans, resulted in ensheathment defects of peripheral nerves in Drosophila. A genetic dissection study combined with shotgun high-resolution mass spectrometry of lipids showed that levels of ceramide phosphoethanolamine are crucial for axonal ensheathment by glia. A detailed morphological and functional analysis demonstrated that the depletion of ceramide phosphoethanolamine resulted in axonal defasciculation, slowed spike propagation, and failure of wrapping glia to enwrap peripheral axons. Supplementing sphingosine into the diet rescued the neuropathy in flies. Thus, our RNAi study in Drosophila identifies a key role of ceramide phosphoethanolamine in wrapping of axons by glia.
Repeated macrofungal explorations, followed by thorough examination of species through morphology and molecular phylogeny, have made it clear that European and American names of wild mushrooms were ...inadvertently misapplied quite often to Asian lookalikes by mycologists/taxonomists in the past. Therefore, in order to reveal this mushroom treasure, in recent years, taxonomical research on wild mushrooms has been intensified in Asian countries, including India, by undertaking a combined approach of morpho-taxonomy and multigene molecular phylogeny. Boletoid mushrooms (Boletaceae) are no exception. While working on boletoid mushrooms of the Indian Himalayas, authors recently came across six interesting species of boletoid mushrooms. In the present communication, four novel species, namely
,
,
and
, are established based on morphology and molecular phylogenetic estimations. Moreover,
and
are also reported here for the first time in India.
Glial dysfunction has been implicated in a number of neurodegenerative diseases. In this study we investigated the consequences of glial and oligodendrocyte ablation on neuronal integrity and ...survival in Drosophila and adult mice, respectively. Targeted genetic ablation of glia was achieved in the adult Drosophila nervous system using the GAL80-GAL4 system. In mice, oligodendrocytes were depleted by the injection of diphtheria toxin in MOGi-Cre/iDTR double transgenic animals. Acute depletion of oligodendrocytes induced axonal injury, but did not cause neuronal cell death in mice. Ablation of glia in adult flies triggered neuronal apoptosis and resulted in a marked reduction in motor performance and lifespan. Our study shows that the targeted depletion of glia triggers secondary neurotoxicity and underscores the central contribution of glia to neuronal homeostasis. The models used in this study provide valuable systems for the investigation of therapeutic strategies to prevent axonal or neuronal damage.
Russula subsection Amoeninae is morphologically defined by a dry velvety pileus surface, a complete absence of cystidia with heteromorphous contents in all tissues, and spores without amyloid ...suprahilar spot. Thirty-four species within subsection Amoeninae have been published worldwide. Although most
Russula
species in South Korea have been assigned European or North American names, recent molecular studies have shown that
Russula
species from different continents are not conspecific. Therefore, the present study aims to: 1) define which species of Russula subsection Amoeninae occur on each continent using molecular phylogenetic analyses; 2) revise the taxonomy of Korean
Amoeninae
. The phylogenetic analyses using the internal transcribed spacer (ITS) and multilocus sequences showed that subsection Amoeninae is monophyletic within subgenus Heterophyllidiae section Heterophyllae. A total of 21 Russula subsection Amoeninae species were confirmed from Asia, Australia, Europe, North America, and Central America, and species from different continents formed separate clades. Three species were recognized from South Korea and were clearly separated from the European and North American species. These species are
R. bella
, also reported from Japan, a new species described herein,
Russula orientipurpurea
, and a new species undescribed due to insufficient material.
During the course of macrofungal forays, we collected several wood-rotting fungi from three states in India: Bihar, Jharkhand, and Maharashtra. We identified some of these macrofungal collections as
...Favolus roseus
Lloyd. A critical literature survey and taxonomic investigation established that this is the first report of F. roseus from India. We give a detailed morphological description, illustration, and molecular phylogeny of the species, along with taxonomic note and extended biogeographical distributional map.
Russula lakhanpalii is a wild edible mushroom, collected from Pedkhal block of Pauri Garhwal, India. The nutritional composition, antioxidant activity (AOA), and antibacterial activity (ABA) of R. ...lakhanpalii were analyzed for the first time in this study. Dried fruiting bodies of R. lakhanpalii were reported to contain 17.7% ash, 10% crude fiber, 13.4% protein, 30.9% carbohydrate, and 5% unsaturated lipids. In addition, 10.22-72.56% DPPH scavenging activity also confirmed the good antioxidant nature of R. lakhanpalii. The methanolic extract of R. lakhanpalii fruiting bodies inhibited the growth of five pathogenic bacteria in vitro; Klebsiella pneumoniae (MTCC 4030), Micrococcus luteus (MTCC 1809), Staphylococcus aureus (MTCC 1144), Escherichia coli (MTCC 68), and Streptococcus pneumoniae (MTCC 655). The maximum and minimum zone of inhibitions (ZOIs) reported were 17.8 ± 1.04 mm (K. pneumoniae) and 11.16 ± 0.76 mm, (E. coli), respectively. The noticeable feature of the extract was the inhibition of erythromycin-resistant E. coli and M. luteus by it, which were resistant to 15 μg/disc concentration of erythromycin. Dietary components, antibacterial and antioxidant potentials of R. lakhanpalii suggested its nutraceutical and medicinal applications.
Vertebrate nervous systems rely on rapid nerve impulse transmission to support their complex functions. Fast conduction depends on ensheathment of nerve axons by myelin-forming glia and the ...clustering of high concentrations of voltage-gated sodium channels (Nav) in the axonal gaps between myelinated segments. These gaps are the nodes of Ranvier. Depolarization of the axonal membrane initiates the action potential responsible for impulse transmission, and the Nav help ensure that this is restricted to nodes. In the central nervous system, the formation of nodes and the clustering of Nav in nodal complexes is achieved when oligodendrocytes extend their processes and ultimately ensheath axons with myelin. However, the mechanistic relationship between myelination and the formation of nodal complexes is unclear. Here we review recent work in the central nervous system that shows that axons, by assembling distinct cytoskeletal interfaces, are not only active participants in oligodendrocyte process migration but are also significant contributors to the mechanisms by which myelination causes Nav clustering. We also discuss how the segregation of membrane protein complexes through their interaction with distinct cytoskeletal complexes may play a wider role in establishing surface domains in axons.
JAK2-V617F-positive chronic myeloproliferative neoplasia (CMN) commonly displays dysfunction of integrins and adhesion molecules expressed on platelets, erythrocytes, and leukocytes. However, the ...mechanism by which the 2 major leukocyte integrin chains, β1 and β2, may contribute to CMN pathophysiology remained unclear. β1 (α4β1; VLA-4) and β2 (αLβ2; LFA-1) integrins are essential regulators for attachment of leukocytes to endothelial cells. We here showed enhanced adhesion of granulocytes from mice with JAK2-V617F knockin (JAK2+/VF mice) to vascular cell adhesion molecule 1- (VCAM1-) and intercellular adhesion molecule 1-coated (ICAM1-coated) surfaces. Soluble VCAM1 and ICAM1 ligand binding assays revealed increased affinity of β1 and β2 integrins for their respective ligands. For β1 integrins, this correlated with a structural change from the low- to the high-affinity conformation induced by JAK2-V617F. JAK2-V617F triggered constitutive activation of the integrin inside-out signaling molecule Rap1, resulting in translocation toward the cell membrane. Employing a venous thrombosis model, we demonstrated that neutralizing anti-VLA-4 and anti-β2 integrin antibodies suppress pathologic thrombosis as observed in JAK2+/VF mice. In addition, aberrant homing of JAK2+/VF leukocytes to the spleen was inhibited by neutralizing anti-β2 antibodies and by pharmacologic inhibition of Rap1. Thus, our findings identified cross-talk between JAK2-V617F and integrin activation promoting pathologic thrombosis and abnormal trafficking of leukocytes to the spleen.
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