Genome Analysis of Bacillus aryabhattai to Identify Biosynthetic Gene Clusters and In Silico Methods to Elucidate its Antimicrobial Nature

International Journal of Peptide Research and Therapeutics - Biosurfactants such as lipopeptides, lipoketides, and peptides produced by Bacillus species exhibit antimicrobial properties. In the...     

A Leaf Curl Disease in Germplasm of Rapeseed‐Mustard in India: Molecular Evidence of a Weed‐Infecting Begomovirus–Betasatellite Complex Emerging in a New Crop

Evaluation of 130 accessions of rapeseed‐mustard germplasm grown at the National Bureau of Plant Genetic Resources, New Delhi, India during the winter season (2011–2012) revealed the occurrence of a leaf curl disease in seven accessions. The occurrence of the disease was observed in another 62 of 525 accessions evaluated during 2012–2013. The association of a monopartite begomovirus and betasatellite was established with the symptomatic plants by whitefly transmission and PCR amplification. The complete nucleotide sequences of the begomovirus (JX270684, 2745 nucleotides), obtained by rolling circle amplification, showed the highest sequence identity (98.1%) with the weed‐infecting begomovirus, Croton yellow vein mosaic virus. Analysis of recombination indicated the probable occurrence of many overlapping inter‐ and intraspecific recombination events. The sequence of betasatellite (JX270685, 1355 nucleotides) showed the highest sequence identity (95.7%) with Croton yellow vein mosaic betasatellite. Begomoviruses were not previously known to naturally infect rapeseed‐mustard. This is the first report of the emergence of a weed‐infecting begomovirus–betasatellite complex in rapeseed‐mustard germplasm in India and raises the concern on utilization of such susceptible germplasm in crop improvement programmes.     

Involvement of thermoplasmaquinone-7 in transplasma membrane electron transport of Entamoeba histolytica trophozoites: a key molecule for future rational chemotherapeutic drug designing

The quinone composition of the transplasma membrane electron transport chain of parasitic protozoa Entamoeba histolytica was investigated. Purification of quinone from the plasma membrane of E. histolytica and its subsequent structural elucidation revealed the structure of the quinone as a methylmenaquinone-7 (thermoplasmaquinone-7), a napthoquinone. Membrane bound thermoplasmaquinone-7 can be destroyed by UV irradiation with a concomitant loss of plasma membrane electron transport activity. The abilities of different quinones to restore transplasma membrane electron transport activity in UV irradiated trophozoites were compared. The lost activity was recovered completely by the addition of thermoplasmaquinone-7, but ubiquinones are unable to restore the same. These findings clearly indicate that thermoplasmaquinone-7 acts as a lipid shuttle in the plasma membrane of the parasite to mediate electron transfer between cytosolic reductant and non permeable electron acceptors. This thermoplasmaquinone-7 differs from that of the mammalian host and can provide a novel target for future rational chemotherapeutic drug designing.     

Bayesian Total Internal Reflection Fluorescence Correlation Spectroscopy Reveals hIAPP-Induced Plasma Membrane Domain Organization in Live Cells

Amyloid fibril deposition of human islet amyloid polypeptide (hIAPP) in pancreatic islet cells is implicated in the pathogenesis of type II diabetes. A growing number of studies suggest that small peptide aggregates are cytotoxic via their interaction with the plasma membrane, which leads to membrane permeabilization or disruption. A recent study using imaging total internal reflection-fluorescence correlation spectroscopy (ITIR-FCS) showed that monomeric hIAPP induced the formation of cellular plasma membrane microdomains containing dense lipids, in addition to the modulation of membrane fluidity. However, the spatial organization of microdomains and their temporal evolution were only partially characterized due to limitations in the conventional analysis and interpretation of imaging FCS datasets. Here, we apply a previously developed Bayesian analysis procedure to ITIR-FCS data to resolve hIAPP-induced microdomain spatial organization and temporal dynamics. Our analysis enables the visualization of the temporal evolution of multiple diffusing species in the spatially heterogeneous cell membrane, lending support to the carpet model for the association mode of hIAPP aggregates with the plasma membrane. The presented Bayesian analysis procedure provides an automated and general approach to unbiased model-based interpretation of imaging FCS data, with broad applicability to resolving the heterogeneous spatial-temporal organization of biological membrane systems.     

Complementation between Two Tospoviruses Facilitates the Systemic Movement of a Plant Virus Silencing Suppressor in an Otherwise Restrictive Host

Background

New viruses pathogenic to plants continue to emerge due to mutation, recombination, or reassortment among genomic segments among individual viruses. Tospoviruses cause significant economic damage to a wide range of crops in many parts of the world. The genetic or molecular basis of the continued emergence of new tospoviruses and new hosts is not well understood though it is generally accepted that reassortment and/or genetic complementation among the three genomic segments of individual viruses could be contributing to this variability since plants infected with more than one tospovirus are not uncommon in nature.

Methodology/Principal Findings

Two distinct and economically important tospoviruses, Iris yellow spot virus (IYSV) and Tomato spotted wilt virus (TSWV), were investigated for inter-virus interactions at the molecular level in dually-infected plants. Datura (Datura stramonium) is a permissive host for TSWV, while it restricts the movement of IYSV to inoculated leaves. In plants infected with both viruses, however, TSWV facilitated the selective movement of the viral gene silencing suppressor (NSs) gene of IYSV to the younger, uninoculated leaves. The small RNA expression profiles of IYSV and TSWV in single- and dually-infected datura plants showed that systemic leaves of dually-infected plants had reduced levels of TSWV N gene-specific small interfering RNAs (siRNAs). No TSWV NSs-specific siRNAs were detected either in the inoculated or systemic leaves of dually-infected datura plants indicating a more efficient suppression of host silencing machinery in the presence of NSs from both viruses as compared to the presence of only TSWV NSs.

Conclusion/Significance

Our study identifies a new role for the viral gene silencing suppressor in potentially modulating the biology and host range of viruses and underscores the importance of virally-coded suppressors of gene silencing in virus infection of plants. This is the first experimental evidence of functional complementation between two distinct tospoviruses in the Bunyaviridae family.