How do root fungi of Alnus nepalensis and Schima wallichii recover during succession of abandoned land?

Alnus nepalensis and Schima wallichii are native tree species accompanying succession in abandoned agricultural land in the middle mountainous region of central Nepal. To understand how root fungi recover during spontaneous succession, we analyzed the diversity and composition of arbuscular mycorrhizal (AM), ectomycorrhizal (ECM), and total fungi in tree fine roots from three land use types, short-term abandoned land (SA), long-term abandoned land (LA), and regenerated forest (RF) as a reference. Additionally, ECM morphotypes were examined. The results showed different speeds of succession in the studied fungal groups. While the change in the AM fungal community appears to be rapid and LA resembles the composition of RF, the total fungi in the abandoned land types are similar to each other but differed significantly from RF. Interestingly, the relative abundance of Archaeosporaceae followed a trend differing between the tree species (SA < LA in A. nepalensis, but SA > LA in S. wallichii). Unlike AM and total fungi, there was no significant difference in the ECM community of A. nepalensis between land use types, probably due to their low species diversity (9 ECM morphotypes, 31 ECM operational taxonomic units). However, Cortinarius sp. was significantly more abundant in RF than in the other land use types, whereas Alnicola, Tomentella, and Russula preferred young stages. Our results suggest that for both studied tree species the AM fungal succession could reach the stage of regenerated forest relatively fast. In the case of total fungi, because of hyperdiversity and composed of species specialized to a variety of environments and substrates, the transition was expected to be delayed in abandoned land where the vegetation was still developing and the ecosystem was not as complex as that found in mature forests.

Host-pathogen interactome analysis of Chikungunya virus envelope proteins E1 and E2.

The envelope proteins of Chikungunya virus (CHIKV) are known to play crucial roles in viral infection and spread. Although the role of envelope proteins in viral infection has been studied, the cellular interactors of these proteins are still elusive. In the present study, the ectodomains of CHIKV envelope proteins (E1 and E2) have been used for a high throughput yeast two-hybrid (Y2H) screening to identify the interacting host protein partners. Following a comparative analysis between the viral-host protein interaction data generated from Y2H and computational approach, five host proteins interacting with E1 and three host proteins interacting with E2 common to both datasets were identified. These associations were further verified independently by pull down and protein interaction ELISA. The identified interactions shed light on the possible cellular machinery that CHIKV might be employing during viral entry, trafficking, and evasion of immune system.

Network mapping among the functional domains of Chikungunya virus nonstructural proteins.

Formation of virus specific replicase complex is among the most important steps that determines the fate of viral transcription and replication during Chikungunya virus (CHIKV) infection. In the present study, the authors have computationally generated a 3D structure of CHIKV late replicase complex on the basis of the interactions identified among the domains of CHIKV nonstructural proteins (nsPs) which make up the late replicase complex. The interactions among the domains of CHIKV nsPs were identified using systems such as pull down, protein interaction ELISA, and yeast two-hybrid. The structures of nsPs were generated using I-TASSER and the biological assembly of the replicase complex was determined using ZRANK and RDOCK. A total of 36 interactions among the domains and full length proteins were tested and 12 novel interactions have been identified. These interactions included the homodimerization of nsP1 and nsP4 through their respective C-ter domains; the associations of nsP2 helicase domain and C-ter domain of nsP4 with methyltransferase and membrane binding domains of nsP1; the interaction of nsP2 protease domain with C-ter domain of nsP4; and the interaction of nsP3 macro and alphavirus unique domains with the C-ter domain of nsP1. The novel interactions identified in the current study form a network of organized associations that suggest the spatial arrangement of nsPs in the late replicase complex of CHIKV.

Virtual screening of inhibitors against Envelope glycoprotein of Chikungunya Virus: a drug repositioning approach.

Chikungunya virus (CHIKV) a re-emerging mosquito-borne alpha virus causes significant distress which is further accentuated in the lack of specific therapeutics or a preventive vaccine, mandating accelerated research for anti-CHIKV therapeutics. In recent years, drug repositioning has gained recognition for the curative interventions for its cost and time efficacy. CHIKV envelope proteins are considered to be the promising targets for drug discovery because of their essential role in viral attachment and entry in the host cells. In the current study, we propose structure-based virtual screening of drug molecule on the crystal structure of mature Chikungunya envelope protein (PDB 3N41) using a library of FDA approved drug molecules. Several cephalosporin drugs docked successfully within two binding sites prepared at E1-E2 interface of CHIKV envelop protein complex with significantly low binding energies. Cefmenoxime, ceforanide, cefotetan, cefonicid sodium and cefpiramide were identified as top leads with a cumulative score of -67.67, -64.90, -63.78, -61.99, and - 61.77, forming electrostatic, hydrogen and hydrophobic bonds within both the binding sites. These shortlisted leads could be potential inhibitors of E1-E2 hetero dimer in CHIKV, hence might disrupt the integrity of envelope glycoprotein leading to loss of its ability to form mature viral particles and gain entry into the host.