Virology: Current Research

This study aimed to evaluate the utility and efficiency of the Flinders Technology Associates (FTA®) Elute Card (Whatman®) as a sampling device and storage platform for RNA from Betanodavirus infected biological sample (viz., cell culture supernatant). The retrieval of target RNA from FTA Elute Card discs with a diameter ranging from 1.2 - 2 mm was found to be satisfactory for detection of Betanodavirus by reverse transcription-nested polymerase chain reaction (RT-nPCR). The viral RNA on the cards could be detected by RT-nPCR for a minimum period of 30 days of storage at 4°C, though at lower efficiency after 21 days of storage. In conclusion, FTA cards protocol provides a supplementary method for quick and easy collection of samples, preservation of RNA on a dry storage basis and detection of Betanodavirus infected fish.

Leaf samples (seven) from carrot plants exhibiting witches’ broom symptoms were collected from the farmers’ fields of Bangalore Rural and Chikkamaglore Districts of Karnataka, India. The presence of the causal agent was identified through PCR using the 16SrRNA, Ribosomal protein (rp) and SecY gene-specific primers. The seven carrot samples gave positive amplification for the phytoplasma specific primers. The amplified products were cloned and sequenced. The sequence analysis showed that the 16SrRNA, rep gene and SecY gene of seven CarWB phytoplasma isolates shared highest not identity of 94.5 to 97.0%, 94.2 to 98.8% and 99.1 to 99.5% with 16SrRNA, rep and SecY gene of Ca. P. australasiae (16SrII) group isolates reported so far. This result is well supported by close clustering of CarWB phytoplasma isolates in the current study with Ca. P. australasiae (16SrII) group isolates in the phylogenetic analysis. The virtual RFLP pattern generated for the CarWB phytoplasma revealed seven out of six isolates infecting carrot were different (similarity coefficient is ranged from 0.87 to 0.93) with respect to the nine enzymes from the reference pattern of the Ca. P. australasiae (16SrII) subgroups reported so far. Based on the threshold similarity coefficient for the new subgroup, delineation is set at 0.97. Therefore, the six CarWB phytoplasmas may be considered as a new subgroup under Ca. P. australasiae 16SrII group. This is the first the report of a phytoplasma associated with the little leaf disease of carrot from India

The recent discovery of a nuclear giant virus that infects chaetognaths (small marine invertebrates) led us to reanalyze the surprising structures previously observed in this taxon. These elements, initially thought to be bristles and, later, bacteria, have been observed in two species and are in fact viral particles that likely correspond to two host-specific species. All of these viral particles have a spindle (fusiform) shape, an outer envelope and a tegument-like structure surrounding one internal membrane delimiting a compartment containing the genome and proteins. Electron photographs have provided a view of the sequential viral assembly and egress processes, which are concomitant and occur through the cytoplasmic membrane. During viral budding, the tegument-like wall self-assembles from a ring structure. Moreover, in the cell cytoplasm, the viral nucleoid is surrounded by two membranes. The virions that infect Paraspadella gotoi have a length range of ~2.5-3.1 μm and are not completely covered by the envelope revealing a kind of small "paintbrush" that is probably protein in nature. This structure does not appear in the viral particles infecting Spadella cephaloptera, who’s the size of a virus exceeds 4 μm, which is approximately twice the length of the bacterium E. coli and represents the longest known length of a virus. Moreover, they are perhaps the first known photographs of giant viruses (1967). Future genomic studies and further ultra-structural investigations are needed to improve knowledge of these viruses, which may represent a novel virus family for we provisionally propose the name Klothoviridae and the type species Klothovirus casanovai.