What are the types of polyhedrosis?
Subsequently, two different types of polyhedrosis diseases were distinguished: those in which the polyhedra developed in nuclei called nuclear polyhedroses (NPVs), and those with occlusion bodies present in the cytoplasm (Figure 2) called cytoplasmic polyhedroses (CPVs) (4).
How does nuclear polyhedrosis virus work?
The virus enters the nucleus of infected cells and reproduces until the cell begins to produce crystals in the fluids of the host. These crystals can transmit the virus from one host to another. The host becomes visibly swollen with fluid containing the virus, and eventually dies, turning black with decay.
Which disease is caused by nuclear polyhedrosis?
Bombyx mori nucleopolyhedrovirus (BmNPV) causes a disease referred to as nuclear polyhedrosis, jaundice, or blood-type grasserie (from the French word “grasse”, which means thick and sticky and describes the exudates seen in dead silkworms).
What is a helical virus?
In the case of a helical virus, the viral nucleic acid coils into a helical shape and the capsid proteins wind around the inside or outside of the nucleic acid, forming a long tube or rod-like structure (Fig. 2.4 ). The nucleic acid and capsid constitute the nucleocapsid.
What is polyhedrosis in zoology?
: any of numerous diseases that affect specific insect larvae or decapod crustaceans, that are caused by double-stranded DNA viruses of a family (Baculoviridae) or by reoviruses of a genus (Cypovirus), and that are characterized by dissolution of tissues and accumulation of virus-containing granules in the resultant …
What is NPV and GV?
NPV has multiple virions in polyhedral form occlusion bodies while GV has single virion in granule form. NPV strains defined as having a single or multiple nucleocapsid in an envelope. (B) Infection cycle of baculoviruses. 1. Baculoviruses are ingested by insect larvae.
What causes NPV?
As more caterpillars eat the virus particles and die, the virus spreads exponentially. NPV – Imagine this out in a garden, all those drips of liquid splashing everywhere and insects carrying the dissolved caterpillar elsewhere. These were all wild Gulf Fritillary caterpillars brought in for photo purposes.
What is BT mode of action?
Bt has to be eaten to cause mortality. The Bt toxin dissolve in the high pH insect gut and become active. The toxins then attack the gut cells of the insect, punching holes in the lining. The Bt spores spills out of the gut and germinate in the insect causing death within a couple days.
What is spherical virus?
Icosahedral. These viruses appear spherical in shape, but a closer look actually reveals they are icosahedral. The icosahedron is made up of equilateral triangles fused together in a spherical shape. This is the most optimal way of forming a closed shell using identical protein sub-units.
What is NPV disease?
NPV (nucleopolyhedrovirus) is a viral disease of caterpillars that occurs naturally in Australia. As a pesticide, NPV is highly specific, safe and environmentally friendly (does not harm humans, wildlife or other insects), making it ideally suited to include in an integrated pest management approach.
How does Bt protein work?
The Bt toxin dissolve in the high pH insect gut and become active. The toxins then attack the gut cells of the insect, punching holes in the lining. The Bt spores spills out of the gut and germinate in the insect causing death within a couple days.
Is TMV a helical virus?
Helical viruses are typified by the tobacco mosaic virus (TMV) which was one of the first viruses to be understood at a structural level. The capsid of this RNA-containing virus is comprised of 2130 subunits of a single structural protein consisting of 157 amino acids with a molecular weight = 17,400.
Which is tadpole shaped virus?
A typical bacteriophage is like a tadpole shaped consists of a head, enclosing the nucleic acid, a base plate and a tail having tail fiber. The structure has been adopted from Yap et al. [128] Bacteriophages (phages/viruses) need host bacteria to replicate and propagate.
What is cytoplasmic polyhedrosis virus (CPV)?
Cytoplasmic polyhedrosis viruses (CPVs) from the Cypovirus genus infect a variety of insect species. The most studied and economically important CPV is Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) as it causes mortality in silkworm ( Jiang and Xia, 2014 ).
What is a cytoplasmic virus?
Cypovirus (family Reoviridae, subfamily Spinareovirinae) are cytoplasmic polyhedrosis viruses that are commonly isolated from insects, particularly from Lepidoptera. Sixteen species have been reported so far (ICTV, 2014 ).
What is the structure of a virus?
The viruses replicate in the cytoplasm and have a linear double-stranded RNA genome composed of 10 segments. The virions are nonenveloped icosahedrons, embedded in a protein matrix to form occlusion bodies.
What is Payne’s 1976 Provisional classification of cytoplasmic polyhedrosis viruses?
Payne, C.C., and Rivers, C.F., 1976, A provisional classification of cytoplasmic polyhedrosis viruses based on the sizes of the RNA genome segments, J. Gen. Virol. 33 :71. PubMed Google Scholar